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International Conference on Advances in Radiation Oncology #ICARO2


The International Atomic Energy Agency (IAEA) is organizing the second International Conference on Advances in Radiation Oncology (ICARO2), following the success of the first conference (ICARO), which was held in 2009. The advances in radiotherapy in the last years have been striking, although numerous challenges are still to be faced, including achieving access to high standard cancer care in many countries. New radiotherapy techniques have been implemented in the past decade, including three-dimensional conformal therapy, stereotactic radiotherapy, intensity modulated radiation therapy, image guided radiation therapy, tomotherapy, new brachytherapy and unsealed-source techniques, and proton and heavy ion therapy. The increased use of these complex techniques, coupled with the need to treat more patients in less time, will continue to drive a reliance on high-end technologies and impose a financial burden on health care programmes. In addition, the development and implementation of a quality assurance programme for these new techniques is a major challenge in Member States.

The conference will give health care professionals an opportunity to review the current developments in clinical applications in the fields of radiation oncology, radiation biology and medical physics, with a view to addressing the challenge of cancer management in Member States.

It will also critically examine the pivotal role of emerging radiotherapy techniques in tackling the health challenges common to many Member States.

An appropriate number of accredited continuing medical education (CME) credits will be awarded to participants.

ICARO2 Flyer
ICARO2 Poster
  • Ruben Gomez
    • Registration Gate 1

      Gate 1

    • Session 1 - Opening ceremony M1


      • 1
      • 2
      • 3
    • Session 2 - From ICARO-1 to ICARO-2 M1


      Learning objectives:
      1. To know the advances in radiation oncology since ICARO1 (2009)
      2. To understand the challenges in the field of radiation oncology in the near future

      Conveners: Dr Eduardo Zubizarreta (Section Head ARBR - NAHU - IAEA) , Mr Geoffrey Ibbott, Ms May Abdel-Wahab (IAEA)
      • 4
        From ICARO1 to ICARO2: the radiation oncologist perspective
        Advances in the understanding of the etiology of cancer and its treatment continue to happen, but they are gradual and slower than desirable. Radiotherapy continues to be one of the three main pillars of cancer treatment and is still very relevant in the treatment of some of the most common adult cancers. These include head-and-neck tumours, lung, esophagus, breast, rectum, prostate and gynecological malignancies particularly cervical cancer. Progress in radiation oncology has been largely due to developments in three fronts: [1] clinical trials, [2] biology and radiobiology and [3] technological advances in computing, imaging and radiotherapy delivery systems. The current paradigm of evidence-based medicine makes prospective randomized trials and meta-analysis powerful tools to generate knowledge which is then applied in clinical practice. The use of cisplatin as a radiosensitizer in cervical cancer has become standard and has improved outcomes, and is the result of such clinical trials. The use of hypofractionation in certain sites also reflects the impact of clinical research. Dose escalation in localized prostate cancer as well as combination of RT with hormone therapies is the result of a long series of well-planned trials. Radiotherapy in breast conservation as well as post-mastectomy and the irradiation of lymph nodes groups is another of many examples, as is the role of radiotherapy for organ/function preservation in laryngeal, bladder and rectal cancers. The combination of radiotherapy and targeted therapies seems a promising approach, particularly with the inhibitors of the EGFR pathway and anti-vascular treatments, and require the continuation and intensification of clinical trials. Advances in computerized treatment planning and in the delivery equipment have had a great positive impact. The development of three-dimensional conformal radiotherapy (3D-CRT) has definitively improved clinical outcomes and should be the standard approach to curative radiotherapy. Subsequent refinements of the 3-D approach such as IMRT, IGRT, SBRT have become established in developed as well as developing countries. These techniques allow not only a more precise deposition of dose in the target volumes, but this is achieved with reduced toxicity levels. Further improvements in the planning and delivery of radiation allowed techniques such as intensity modulated arc therapy; helical tomotherapy and robotic radiotherapy which have become very popular although at present, their high cost limits further deployment in countries with limited resources. The dosimetry of small radiation beams, associated with these modalities is developing fast. The clinical realization of MRI-guided radiotherapy could represent the ultimate breakthrough in real-time image guidance – offering soft-tissue-based imaging throughout beam delivery. As such, researchers have been working for more than a decade to overcome the substantial technical obstacles required to integrate an MRI scanner with a linear accelerator. These systems are now under clinical testing. The use of positively charged light ion beams in radiotherapy –mainly the proton beam, but to a more limited extent also carbon ion radiotherapy -has generated enormous interest and development. At this time there are 61 operational proton facilities and 10 carbon ion facilities and a total of 43 facilities are under construction. There are encouraging clinical results of the use of the proton beam and a preferential indication for protons exists in about 14-15% of patients requiring radiotherapy. Laser-accelerated proton beam radiotherapy is under development. Efforts are underway at CERN to develop a mini-accelerator for particles for medical use. The “mini-RFQ” can produce low-intensity beams, with no significant losses, of just a few microamps that are grouped at a frequency of 750 MHz. These specifications make the “mini-RFQ” a perfect injector for the new generation of high-frequency, compact linear accelerators used for the treatment of cancer with protons. Clearly, particle radiotherapy will be part of the future of radiation oncology.
        Speaker: Eduardo Rosenblatt (IAEA)
      • 5
        From ICARO1 to ICARO2: the medical physicist perspective
        Speaker: Geoffrey Ibbott
    • Tuesday morning - Poster Presentations - Screen1
      Convener: Mr Oleg Belyakov (IAEA)
      • 6
        A centralized model of effective radiation oncology service development:the Azerbaijan Republic experience
        The history of radiotherapy in Azerbaijan starts in 1940with the establishment of the Scientific Research Institute of Roentgenology and Radiology (SRIRR). At that time Azerbaijan was part of the former USSR. In the beginning,the Institute was equipped with X-ray orthovoltage machines and one teletherapy machine with cesium source.Radium sources were used for brachytherapy.. In 1956 the first cobalt unit was installed. Thereafter and up to the collapse of the USSR, four more cobalt machines and several X-ray machines of soviet manufacture were provided which yielded to western analogs. In 1985 the first and only afterloading brachytherapy unit was installed, which got out of order in a few months and has never since been repaired. The crisis of the Soviet system led to the deterioration of economic and social spheres including healthcare in general, and radiotherapy in particular in all republics of the former Soviet Union. Isolation from the rest of the world and absence of cooperation of our oncologists with specialists outside the USSR did not allow gettingaccess to updated information on the latest radiotherapy developments. As a result, in early 2003 there were only three othovoltage X-ray machines and two cobalt machines which sources had not been changed for 18 years. For this reason the treatment of one patient lasted up to 40 minutes. After Azerbaijan’s independence we could only avoid a complete collapse of radiotherapy services due to awareness of the importance of radiation oncology by the management of the National Center of Oncology (the former SRIRR) who raised the problem before high level Government authorities. Since then, the situation has dramatically changed. This was followed by the Azerbaijan Republic presidential decree "On the cancer care", which served as an additional boost for the development of radiation therapy. In 2003 the Azerbaijan Government signed a cooperation agreement with the International Atomic Energy Agency (IAEA) one of the tasks of which was improvement of radiotherapy services quality in the country. As a result, the National Cancer Care Program was established covering prevention, early detection, effective treatment and palliation of oncological patients. It also includeda radiation therapy development program. A very important factor in our case is the existence of a close interaction between state legislative, financial structures and healthcare authorities. This was the basis for making appropriate and goal oriented decisions taking into account radiotherapy service demands defined by specialists in radiation oncology with a public health perspective. The Radiation therapy development program incorporates a policy of carefully planned, stepwise implementation of modern methods of radiation therapy in practice. Especially the technological developments in radiotherapy we have witnessed in the past 10 years. It has become clear that the only right way to achieve a goal in this area, is the combination of factorssuch as: governmental support (both legislative and financial support taking into consideration the heavy expenses for equipment and facilities),investment in staff education and training and the guidance and recommendations of experienced international organizations like the IAEA, WHO, and ESTRO.Taking into account the relative complexity and costliness of radiotherapy service in general, relatively small population (about 10 million) and short travel distances in our countryand after thorough discussions with health care administration of the Republic we have decided to adopta so called centralized system of radiotherapy service in Azerbaijan. Following the Radiation therapy development program,for 2003 to 2013,a high level dedicated radiation oncology center was established on the basis of the existing radiotherapy department of the National Center of Oncology (NCO) of the Ministry of Health of the Azerbaijan Republic. The most conformal and precise treatment modalities such as 3D conformal radiotherapy, IMRT, VMAT, SBRT, IGRT, SRS, 3D image guided interstitial brachytherapy are now implemented at NCO with a flow of 2000-2500 patients per year. Two additional radiotherapy centers were established in other regions equippedwith orthovoltage machines and cobalt units. These units are significantly less expensive and easier in their operation and service. The vast majority of palliative treatments in the country are carried out in these two satellite centers. Conclusion. The centralized radiotherapy service is feasible from both organizational and effective treatment points of view in relatively small countries like Azerbaijan.Long-term strategic planning and purposeful progressive implementation according to objective demands in radiotherapy techniques, governmental support, close interaction between state legislative and financial structures, country’s medical society and authorized international organizations are keyfactors for the successful development of an effective radiotherapy service in a country.
        Speaker: Isa Isayev
      • 7
        Audit of the radiotherapy waiting times for patients in Malta
        ***Introduction*** The Radiotherapy Patient Pathway (RPP) outlining the major stages involved from date of patient consultation to treatment was established for Sir Anthony Mamo Oncology Centre (SAMOC) for all patients receiving radiotherapy. Figure 1 below is an illustration of the main stages, as a subset of the RPP, which were included in this audit. An audit of the established RPP was performed to determine the waiting times at specific stages and the overall waiting time. Waiting times were also sub-divided per treatment site. ![Figure 1: An illustration of the main stages of the RPP][1] ***Method*** A sample of 290 patients, based on a 95% confidence interval and 5% margin of error, was randomly generated as a representation of the patient population of 1 year. Records were selected both retrospectively and prospectively over a 7 month period. A proportional sampling method was used to subdivide patients into 6 treatment sites: Palliative; Breast; Prostate; Pelvis; Abdomen/Thorax; Head&Neck. Each patient journey was mapped on the RPP and the date of arrival at each stage was recorded. Statistical analysis was performed to determine the weighted mean, median and mode waiting times for all records analysed. ***Results*** Results indicate an overall total weighted mean waiting time of 36 days with a maximum of 62 days for Prostate and a minimum of 19 days for Palliative. Analysis of the waiting time between specific stages of the RPP showed a total weighted mean of 8 days from Consultation to date of CT scan; 13 days from date of CT scan to arrival at the Medical Physics department; 15 days in the Medical Physics department, and 8 days from the Pre-Treatment stage to the Treatment Date. ***Conclusions*** Methods of decreasing patient waiting times across the RPP should be explored in order to provide a more timely radiotherapy service at SAMOC. Recommendations for a more efficient workflow include the further development of an existing oncology information system MosaiqTM, and developing and re-engineering the organisation structure within the context of a multidisciplinary team. [1]:
        Speaker: Chantelle Said
      • 8
        Trend of availability and use of Intensity-Modulated Radiotherapy(IMRT) in Thailand, statistical report from 2008 to 2015.
        **Introduction of the study** Since the introduction of IMRT in late 1990, it gradually becomes a standard or recommended radiotherapy techniques for many kinds of cancer. However, its implementation needs a lot of resources which preventing its availability in developing country like Thailand. This study is aimed to report the growth of availabilty and use of Intensity-Modulated Radiotherapy (IMRT) in Thailand and tried to find the resource factors which are associated with the use of IMRT. **Methodology** Annual statistical reports published by Thai Association of Radiation Oncology(THASTRO) were used for analyses. Availability of IMRT-capable machines were drawn from machine statistics and the use of IMRT was analysed by number of patients, number of patients per available machines and as a percentage of IMRT patients. Analyses were performed in overall data and grouped by geographic location and type of radiotherapy center. Manpower and other resource factors were also analyses. **Results** The first implementation of IMRT in Thailand was in 2003 but the annual statistical reports were available only from 2008 to 2015. Overall from 2008 to 2015, Availability of IMRT-capable machines was increasing from 9 machines to 42 machines and the use of IMRT was increasing from 615 patients (2.5%) to 4083 patients(12.52%). When considered with geographic distribution, the growth of IMRT availability and use were mostly observed in Bangkok (Capital of Thailand). IMRT-capable machines in Bangkok was increasing from 7 machines to 28 machines compared to 2 machines to 14 machines in the rest of country. Growth of IMRT use was also different, it was increasing from 559 patients(5.22%) to 3296 patients(19.81%) in Bangkok compared with 56 patients(0.41%) to 787 patients(4.92%) in the rest of country. Interestingly, the effiency of IMRT use per IMRT-capable machines were better in Bangkok, the average number of IMRT patients per machine in 2015 were 106.61 and 51.65 in Bangkok and the rest of country, respectively(p=0.05). This difference might be explained by the significant higher workload for radiation oncologist and medical physicist, the average number of patients per one radiation oncologist and medical physicist were 158.3 and 223.22 for centers in Bangkok compared to 316.09 and 552.82 for centers in the rest of country (p=0.0024 and 0.0058, respectively) **Conclusion** Availability and use of IMRT in Thailand was gradually increased but mostly concentrated in Bangkok. This should urge the attention of policy makers to improve the assessibility and distribution of IMRT in Thailand. **Acknowledgement** The authors thank Dr. Temsak Phungrassami and all THASTRO coordinators of THASTRO annual survey for the statistic reports.
        Speaker: Poompis Pattaranutaporn (Ramathibodi Hospital)
      • 9
        Radiotherapy in cancer treatment in Ghana: from the past to present
        Cancer is a complex disease and should be a concern for all since we are all at risk of any type of cancer at a point in our lives. Early detection coupled with effective treatment is almost impossible without the existence of the requisite equipment and trained personnel. The world has made a huge progress in cancer treatments, research and advocacy and Ghana is no different. Radiotherapy is a form of treatment for cancer that uses carefully measured and controlled high energy X-rays to kill cancer cells. Radiotherapy forms a greater percentage of cancer treatment, which is one of the most cost-effective. Although the number of radiotherapy facilities in the country are inadequate, Ghana has made some strides in the development of its radiotherapy facilities. According to the World Health Organisation, over 50% of all cancer patients require Radiotherapy at one stage or the other in the course of the disease for treatment and 40% of all the cancer cures result directly from the use of Radiotherapy. In Ghana, cancer of cervix is currently the most common cancer among women, and Radiotherapy plays a major role in its management. Radiotherapy is a specialised treatment and is not available in every hospital. In Ghana, Radiotherapy Services can be assessed at Korle-bu Teaching Hospital in Accra, Komfo Anokye teaching Hospital in Kumasi, both public facilities and the Sweden Ghana Medical Centre in Accra which is a private centre. Radiotherapy was introduced to Ghana in 1992 when the first radium brachytherapy was performed with the aid of the German Government. Before this, there had been unsuccessful attempts to establish a radiotherapy centre in Ghana since 1960. During that period a cobalt machine was donated by the Canadian Government to be used for medical purposes. However, because of lack of funds to house it, the machine was donated to the Lagos University Hospital in Nigeria. Korle-bu Teaching Hospital radiotherapy centre became operational in 1997 and the Komfo Anokye Teaching Hospital radiotherapy centre started treatment in June 2005 both with a strong support from the International Atomic Energy Agency through the Ghana Atomic Energy Commission. Presently, external and internal radiotherapy are available at both hospitals with low dose rate (Cesium-37) in Kumasi and high dose rate (cobalt-60) in Accra. The Korle-Bu and Komfo Anokye Teaching Hospitals’ Radiotherapy Centres now provide a comprehensive service, treating over 1000 patients a year. A lot of patients have been treated so far with radiotherapy in Ghana, over a quarter of whom are women with cervical cancer. Many of them are farmers especially at the Komfo Anokye Teaching Hospital.The high number of patients is further exacerbated by the fact that the neighbouring countries of Côte d’Ivoire, Burkina Faso, Togo, Benin and Sierra Leone have no Radiotherapy treatment facilities of their own. Hence most of their cancer patients who require radiotherapy are referred to Ghana for treatment. The establishment of these centres have also reduce the number of patients who travel abroad for radiotherapy services. Ghanaians can therefore have the luxury of being treated in the country by fellow Ghanaians. Due to the high cancer cases coupled with lack of accessibility and modernisation in Radiotherapy practice there is the need for further development in this specialty. The Population of Ghana has since increased from the time this centres were established. The population of Ghana is currently estimated to be approximately 25million, with a male to female ratio of 49:51. Where a 70% of this population is living in the south of the country with the majority of these, living in the Ashanti and Coastal regions. The two major radiotherapy centres are 250km apart making accessibility a challenge. In response to this challenge the Government of Ghana recently acquired a $13.5 million from the OPEC Fund and the Arab Bank for Economic Development in Africa for the upgrading and expansion of the two radiotherapy centres in Accra and Kumasi. Under this expansion project, the old cobalt units are being replaced with 2 Linacs and a new cobalt unit. A 6 MV Linac along with the new cobalt unit are being installed in Accra, while a dual energy 6/10 MV Linac is being installed in Kumasi. Due to the advancement in radiotherapy, linacs are mostly the standardised machines used in all modern Radiotherapy Centres in the World. Moreover, other obsolete equipment will be replaced and the human resource will be strengthened. In all these the IAEA has been very instrumental with alot of projects in the country. Currently two staffs of Komfo Anokye Teaching Hospital are currently on International Atomic Energy Agency fellowship on advance radiotherapy training in partnership with the International Centre for theoretical physics(I.C.T.P) in Italy.
        Speaker: Emmanuel Worlali FIAGBEDZI (Komfo Anokye Teaching Hospital)
      • 10
        The risk for developing a second primary tumor in long surviving cancer patients
        Introduction: Survival rate in cancer patients has increased in recent years and it is still growing. In these patients, there is a significant risk for developing a second primary tumor because of risk factors like genetic background, unhealthy behaviors or side effects from the therapy of first cancer. The goal of this study was to evaluate the frequency of incidence of different cancer types diagnosed in readmitted long-term survivors. An additional goal was to assess the risk for developing a metachronous cancer in patients with long-term survival. Methodology: From the patients admitted tothe Oncology Insitute, Cluj-Napoca,Romania, in 2014-2015,we selected only those patients who were first admitted to the same inistitute at least 5 years prior to 2014-2015. For these patients we evaluated the reasons of the first presentation, as well as those for the 2014-2015 readmission. Furthermore, we analyzed every case with metachronous tumor by considering the location of the first and second primary tumour. Results: Between2014 and 2015 a total of 5080 cancer patients were admitted to the Oncology Institute Cluj-Napoca, Romania. 110 (2.17%) of these patients were first admitted more than 5 years ago. 25 (22.7%) of these 110 patients had no signs of oncologic disease, 21 (19.1 %) had a continuous disease progression, 20 (18.2%) had a relapse after a free disease period, and 44 (40%) had a second primary tumor. Median age in this group was 65, with a median survival of 12 years after the diagnosis of the first malignancy. The female to male ratio F : M was 1.3:1. In the men’s subgroup, head and neck cancers were found in 11 patients (23% of the cases), lung cancer in 7 (14.6%), central nervous system cancer in 5 (10.4%), and each of colon and urinary bladder cancer in 3 (6.3%) patients. In the women’s subgroup, breast cancer was diagnosed in 14 patients (23.3% of the cases), cervical cancer in 8 (13.3%), endometrial cancer in 7 (11,7%), ovarian cancer in 6 (10%), and each of head and neck and soft tissue cancer in 4 (6,7%) cases. In men with long-term survival (more than 5 years), 45% of those who were previously diagnosed with head and neck cancer developed in time a second primary cancer (5 of 11). Similar results for lung and prostate cancer patients were 28.5% (2 of 7) and 25% (2 of 8) respectively. None of the 5 cases of long term survivors of brain tumors developed second cancer. In the women’s subgroup, 12 of 14 (85%) of the patients who had breast cancer were diagnosed with a second malignancy. The corresponding data for cervical cancer was 4 of 8 (50%), for endometrial cancer 3 of 7 (42.8%), and for ovarian cancer 1 of 6 (16.66%).When common primary cancer sites are compared for both sexes, head and neck cancer was found to be significantly more frequent in men (23% vs 6.7%, p=0.01); for lung cancer it was (14.6% vs 3.3%, p=0.03) and for urinary bladder cancer it was 6.3% vs 0%, with a p value of p=0.05. Conclusion: 4 of 10 of the long-term survivors readmitted in the Oncology Institute were diagnosed with a second malignancy. In men, the most frequent first cancer was head and neck, and breast cancer was women's most frequent malignancy. A comparison of common cancer sites for both sexes show the following: head and neck, lung and urinary bladder cancers were more common in men. Almost half of the men surviving for more than 5 years after being diagnosed with a tumor on the head and neck were diagnosed with a second cancer. The same situation was found for almost a third of the men who were previously diagnosed with lung cancer and a quarter of those who were previously diagnosed with prostate cancer. In women, the reason for readmission for 85% of the patients with breast cancer diagnosis more than 5 years ago was the occurrence of a second primary tumor. Cervical cancer and endometrial cancer also represented an increased risk (around 50%) of developing a new primary cancer.
        Speaker: Monica-Emilia Chirila (Institute of Gastroenterology, Department of Internal Medicine, Cluj-Napoca, Romania)
    • 10:30 AM
      Coffee break and e-Poster presentations
    • Tuesday morning - Poster Presentations - Screen2
      Convener: Mr Oleg Belyakov (IAEA)
      • 11
        Cost of radiotherapeutic management of patients with cancer in regional cancer center in India
        Introduction: With around 10,00,000 new patients with cancer annually, India accounts for more than half of burden of cancer patients in developing countries. Multi-modality management of cancer, technologic and skill intensive diagnosis and therapy causes significant strain on already burdened health-care system of developing countries. Grant-in-aid is provided by government, various national and international organizations to facilitate prevention and management of cancer in resource-poor countries like India. However optimal utilization of these resources requires computation of cost of cancer management of individual cancer by site / system and histology. Political pressure has become drivers in reducing waiting time and provision of any radiotherapy to patients presenting to oncology centers. In such milieu, we need to compute the cost of radiotherapy in developing countries to plan for future budget outlay and investment. Methods: Data regarding technology/technique required to start any radiotherapy for patients with cancer was obtained from radiotherapy planning register. Data of patients with cancer treated by single radiation oncologist in Department of Radiation Oncology, Kidwai Memorial Institute of Oncology, Bangalore from August 2012 to October 2016 was collected. Results: Cost of 3D conformal radiotherapy management of 12 pediatric tumor, 50 brain tumors, 70 head and neck cancer, 20 thoracic malignancies, 6 breast cancer and 5 gynecologic malignancies were INR 2,40,000, 32,10,000, 53,40,000, 15,00,000, 4,10,000 and 3,40,000 respectively. Cost for radiotherapy management of around 480 patients is 8400000, 1080000, 1176000 and 192000 for Co-60 teletherapy, HDR brachytherapy, LDR brachytherapy and x-ray simulation respectively. Conclusion: 3D conformal radiotherapy for nearly 160 patients costed INR 1,10,40,000 and treatment by Co-60 teletherapy for management of 480 patients costed INR 8400000 over the period of four years. Treatment by 3D conformal radiotherapy is 3 to 4.5 times more expensive that that by Co-60 teletherapy equipment. However, malignancies of brain, lung, nasal cavity, nasopharynx, stomach, pancreas, gall bladder, prostate, pediatric tumors are best managed by 3D CRT or IMRT.
        Speaker: Ramaiah Vinay Kumar (Kidwai Memorial Institute of Oncology)
      • 12
        Photon boost after lumpectomy in breast cancer and acute toxicities in NwGH & RC
        Introduction: One of the common methods in radiation therapy of Breast cancer is whole breast irradiation followed by tumor cavity boost (TCB) with electron therapy. The tumor cavity boost following Whole Breast Irradiation (WBI) is well-defined and there are numerous delivery methods of radiation therapy. In our institution we don’t have the facility of electron, so our study comprised of experiencing the TCB with photons. Although photon boosts have been discouraged because of excess normal tissue toxicity. In our study we have analyzed acute skin reactions and lung doses for the level at 2Gy. Methods: Patients (n=19) of post-lumpectomy breast cancer for both left and right sided node negative were scanned for this study. Mean age for the patients was 47 year .All women were planned for 50 Gy for the whole breast irradiation via tangents followed by TCB irradiation of 10 Gy with standard fractionation. Contouring of breast, cavity, lungs and heart were done in all the cases. Mean volume of breast and cavity were 1000 cm3 and 60 cm3 respectively. These patients were observed for skin toxicity during radiotherapy as per RTOG skin toxicity criteria. Results: The mean lung volume receiving 2 Gy was 27cm3 and V20 for lung is 10% volume for 60 Gy plan. Out of total 19 patients, 75 % patients had grade-II skin reaction at treatment completion and 25 % patients had grade-I skin reaction. Mean heart dose for 60 Gy plans were 100 cGy. While dosimetric analysis it has been found that conformality, dose homogeneity index (DHI) and Tumor cavity coverage was significantly covering up to 95%. Conclusion: Although electrons can be used for TCB but in our centre electron beam therapy is not available and TCB is done with photon beam following the tangential beams. In the adjuvant treatment of breast cancer therapy, whole breast radiation followed by conformal photon boost seems to be acceptable in focus of the skin toxicity, TCB dose distribution and OAR less excessive doses.
        Speaker: Muhammad Aqeel Hussain (Northwest General hospital & Research Centre)
      • 13
        Atypical meningiomas: is there a role for post-operative radiotherapy?
        **Purpose**: The optimal post-surgical management of atypical meningiomas remains controversial. The aim of this study was to review the long-term outcomes of patients with atypical meningioma following surgery and to identify potential prognostic factors for disease progression. **Materials and Methods**: From August 1992 to August 2013, 72 patients with atypical meningioma were treated at our institution. Patients with multiple tumors, neurofibromatosis type 2 or inadequate imaging follow-up were not eligible. We performed pre- and post-operative serial measurements of tumor volume from magnetic resonance imaging. We assessed age, gender, tumor location, bone involvement, extent of resection, tumor growth rates, use of adjuvant post-operative radiation therapy (PORT), and tumor volume at time of radiation therapy (RT) using uni- and multivariate analysis to determine their impact on disease recurrence. Pathology was reviewed in all patients using the WHO 2007 classification. All patients underwent surgical resection at our institution. The extent of surgical resection was established by post-operative imaging and by the surgeon’s assessment at time of surgery based on Simpson’s grading system. RT was delivered either in the adjuvant post-operative setting (PORT) or at time of tumor recurrence or progression. When used, RT was planned with a gross target volume (GTV) including any residual disease and the surgical cavity, based on a post-operative MRI or on MRI findings at time of disease recurrence. Typically, a clinical target volume (CTV) was created by adding a radial 1 cm margin without cropping-off the meningeal barriers and with inclusion of the inner plate of the skull, if applicable. An additional 3-5 mm was usually added for the planning target volume (PTV). A median dose of 54 Gy (range: 52.2-59.4) at 1.8 Gy per fraction was delivered using different techniques. In case of tumor failure, hypo-fractionated schedules or SRS were used, typically 40 Gy in 16 fractions or single fraction SRS of 8 Gy or 12 Gy, respectively. One patient received concomitant Temozolomide and RT after experiencing a third post-surgical failure. **Results**: Gross total resection (GTR) was achieved in 42 patients (58%) and subtotal resection (STR) was achieved in 30 (42%). PORT was delivered to 12 patients (28.6%) in the GTR cohort and in four (13%) in the STR cohort. The 5-year recurrence-free survival rates for GTR patients with or without PORT were 100% and 30.6%, respectively (p<0.01). Whereas disease control rate for STR patients +/- PORT were 75% and 4%, respectively (p=0.0038). Multivariate analysis revealed that the only significant independent prognostic factors for disease progression were lack of PORT and STR with a HR of 6.83 (95%CI 1.94-24) and 6.21 (95%CI 2.69-14.36), respectively. Residual tumor volume greater than 8.76 cm3 at time of RT was associated with a reduced recurrence-free survival (6.7% vs 44.4 %, p=0.0013). In patients not receiving RT, the median relative growth rate was 115.75%/year, the median absolute growth rate was 4.23 cm3/year and tumor doubling time was 9 months. Post-RT these indices were reduced to 74.5%/year, 2.49 cm3/year and 21 months, respectively. We detected tumor failure earlier on follow-up imaging studies by performing volumetric rather than planimetric measurements. We observed a median time lag between the two detection methods of failure of 18 months. At time of tumor failure diagnosis, the median disease volume on volumetric measurement was 4.89 cm3 compared to a median of 12.3 cm3 for planimetric measurement (i.e. the tumor volume will be already at least 50% larger by the time of planimetric detection), p = 0.0003. Treatments were well-tolerated no no grade 3 or higher toxicity being recorded. **Conclusion**: PORT was associated with improved recurrence-free survival in patients with GTR atypical meningioma. Our study provides new information on the importance of using volume measurement to determine tumor failure and also establishes parameters on tumor growth indices that may aid physicians in identifying patients who may benefit from a more aggressive post-operative management either on the adjuvant setting or at time of recurrence.Our results suggest that patients with residual tumor volume larger than 8.76 cm3 have an increased failure rate and should be considered for early RT. Further prospective, randomized studies are definitively needed to unequivocally establish the role of RT in atypical meningiomas..
        Speaker: Luis Souhami (McGill University Health Centre)
      • 14
        Roadmap for setting up a comprehensive state of the art radiation oncology facility at Mbingo Baptist Hospital (MBH) Cameroon
        INTRODUCTION: Radiotherapy is an essential cancer treatment which according to experts suggestions contributes to four in ten cases where cancer is cured.1 It is a relatively cheap, safe, 2 cost-effective treatment that is associated with high levels of patient satisfaction 3. Yet radiotherapy is still lacking in many African countries. Cameroon with a population of 22.3 million inhabitants has two radiotherapy units, however these services do not get the due attention they deserve compared to other cancer treatment modalities. Considering the growing global burden of non-communicable diseases, particularly cancer, which has become a leading cause of mortality and disability in low- and middle-income countries, with more people across the world developing cancer than ever before, and with over two-thirds of all cancer-related deaths occurring in developing countries, there is an urgent need to get into action to fight for a better cancer health care in underserved areas. METHOD: The first step was a comprehensive assessment of the necessity of Radiation Therapy at a selected hospital. The Mbingo Baptist Hospital (MBH) is a 300 bed hospital located in the North West province of Cameroon in Central Africa. Due to the broad spectrum of treatment modalities being offered at this hospital and the fact that patients come in from all over Cameroon, the hospital is being developed into a referral, teaching hospital. As concerns management of cancer, surgery is being offered. There is a pathology unit and also the possibility of receiving Chemotherapy on site. These and more make MBH one of the advanced centers in Cameroon where diagnosing cancer is possible and at least two treatment options can be administered. The hospital records show that close to 2000 patients have been diagnosed of cancer. The most common cancer cases seen are breast, cervical, kaposi sarcoma and now due to a specialized training program in Head and Neck Surgery many of the patients treated in this program have some form of cancer. Unfortunately, Radiotherapy, being an inevitable treatment modality in the successful treatment of advanced stages of Head and Neck cancer and cervical cancer, does not exist at this hospital. To follow up with the establishment of a comprehensive cancer care program at MBH: - Colleagues from the US and Germany in the field of Radiation Oncology (Doctors, Medical physicists and specialists in Radiation protection) first met to assess the need and feasibility of such a project on site. - Get in contact with already existing facilities in Douala and Yaounde. - Meet with the authorities of the hospital to address the need and importance of such an infrastructure. - Involve the Dean and staff of the medical school at the Capital for cooperation. - Visit the National Radiation Protection Agency in Yaounde as concerns safety regulation standards. -Make an estimate of the financial burden required to complete such a project, work on the project’s blueprint and set a deadline for project completion. RESULTS: At the end of the journey, it was clear that MBH will not be able to carry the burden of such a project in totality. A roadmap created for establishing a comprehensive cancer center at Mbingo. Radiation oncology health professionals from Germany and the USA have committed to the project with plans to support in training of local staff. After brainstorming on different ways to assist the funding of the project, it was concluded that the diaspora and international partners get involved and making sure that MBH guarantees for a reliable stable source of power was outlined. It was also concluded that such a facility will need housing possibility also for the relatives of patients being treated at the center. To guarantee sustainability, long term strategies of collaboration via internet and Telemedicine with colleagues abroad would be mandatory. CONCLUSION: The project is at its initial stage but the initiators and driving forces of it have the strong will to see it successful. To our knowledge, this is the first attempt for a mission hospital to come up with a radiation oncology project in Cameroon and we believe the success of this project will be a motivation for others to follow. For the success of this project, we rely on financial assistance from persons and organizations of goodwill.
        Speaker: Rebecca Buecker (Klinikum Lippe)
      • 15
        Radiotherapy in Hue: journey and effort
        PHAM NGUYEN TUONG, MD, PhD* PHAM NHU HIEP, PhD, A. Prof. ** (*)Vice- director of Oncology Center, Head of Radiotherapy Department Hue Central Hospital, Vietnam (**) Director of Hue Central Hospital With a population over 90 millions, the cancer incidence rate in Viet Nam is having more than 150,000 new cases diagnosed every year. National strategy has been implementing, including the development of breast and cervical cancer screening projects, in order to control the cancer growing trend. Initiatives on improving the mortality rate of cancer patients, like enhancing hospital’s infrastructure on cancer treatment facility, allocating extra resources in training programs for medical professionals, are also in progress. Hue Central Hospital, a public regional hospital belonged to Ministry of Health located in central Vietnam providing oncology clinical services including radiotherapy to cancer patients. Oncology Center, formerly known as oncology department, was established in 1995, with just 30 beds. In the beginning, we had a Cobalt-60 radiation therapy machine which treating for about 30 cancer patients per day with 2D techniques. Over the time, the number of patients has been increasing, at peak time this machine (over 2 times of source replacement) covered the treatment for approximately 70 to 90 patients/day. Realizing the treatment overloading, and that the Cobalt-60 machine was becoming obsolete, which specially did not ensure the quality of treatment, we decided to invest a new machine. However, one problem that we had to face to was that the investment capital was limited. Although Hue Central Hospital is a public one, but then, in 2010, the government was not enough money to invest for the the upgrading. Our leaders decided to invest by the socializing model (a private company was responsible for machine installing and maintenance, hospital team was responsible for operation, 40- 60 ratio invesment income sharing). So we had got the Elekta Pricise machine for treatment. Also in that year, the project of upgrading equipments for the oncology center was launched, with ODA (Official Development Assistance) loans from Austrian government with 25 million euros worth. We realized this was an extremely valuable opportunity to strengthen the investment equipments for cancer treatment. With this great project, we equipped with new-generation LINAC radiation therapy systems of Elekta Axesse, modern planning software immobilisation devices, image guidance system.... At the same time with the deployment of equipments, the radiotherapy team has also attended many radiotherapy training courses in Austria, Singapore, Thailand ... to learn more about advanced technique radiation therapy, such as volumes contouring, planning and operation of equipment. The system was put into operation in May of 2015 at time of inaugurating the 8-storey building of oncology center. With this system we have implemented advanced techniques such as IMRT, VMAT, SRS, SRT ... and SBRT recently. Every day there are about 30 patients treated with these techniques. Looking back 20 years of developing cancer radiotherapy in Hue, we found a great effort of overcoming a lot of immanent difficulties to improve continuously the quality of radiotherapy in order to meet the increasing demands of Vietnamese cancer patients.
        Speaker: Nguyen Tuong Pham (Hue Central Hospital)
    • Tuesday morning - Poster Presentations - Screen3
      Convener: Mr Oleg Belyakov (IAEA)
      • 16
        Radiotherapy in Peru: shortage and inequities in access and solution proposal
        Cancer is a health problem in the world and Peru, because of the increased incidence, from 154.5 (estimated GLOBOCAN 2012) to 216.9 (Lima Cancer Registry 2010-2012). Since 2012, the “National Plan for Comprehensive Cancer Care and Improved Access for Oncological Services in Peru” (Plan Esperanza)of Health Ministry offers full coverage of treatment cost by the Seguro Integral de Salud (SIS). The lack of geographical access is shortage and centralization of radiotherapy, with 7 machines in the whole country. It causes treatment delay or abandon due to the long waiting times, high transportation costs, stay, food and laboral absentism of the patient and relatives, among other issues. The purpose of this poster is to propose the decentralization of public radiotherapy in Peru, improving geographic and economic access for cancer patients. SIS affiliates in the country at September 2016 count 17´497,944. Lima is on first place with 22.5%. The 6 northern and southern regions have 29.7% and 17%, respectively. Jungle regions with only have aerial access, Loreto and Ucayali; represent 4.9 and 2.4% respectively. According the IAEA and WHO reccomendations, Peru need 52 Megavoltaje units(MU), distribuited as follows: 11.8 in Lima, 3.6 in Cajamarca, 3.5 in Piura, 3.1 in La Libertad, 2.8 in Cusco, 2.6 in Loreto, 2.5 in Puno, 2.3 in Junin and Ancash, 2.2 in Lambayeque, 2.1 in San Martin, 2.1 in Huanuco, 1.6 in Ayacucho, 1.5 in Arequipa, 1.3 in Callao, 1.2 in Ucayali, 1.1 in Amazonas and Apurimac, 1 in Huancavelica and Ica, 0.5 in Pasco, Tumbes and Tacna, 0.3 in Madre de Dios and Moquegua. We propose in short time (first phase) to setting up of radiotherapy facilities in the hospitals and to distribute 37 MU in 7 regions grouped considering population, preexistence of other oncological services and land transport facilities: 4 MU in Piura, 4 MU in Lambayeque, 2 MU in Loreto, 3 MU in La Libertad, 12 MU in Lima, 4 Mu in Junin, 4 MU in Cusco and 4 MU in Arequipa (see figure). One unit of high dose rate brachytherapy per installation is highly recommended, considering high gynecological cancer incidence. In the medium-long term (second phase), the facility program should continue and expand to other regions with population demand and availability of the other oncological services (chemotherapy, oncologic surgery), such as Cajamarca, San Martin, Ancash, Puno and others.
        Speaker: Paola Carolina Guerrero-Leon (Ministry of Health, Peru)
      • 17
        Clinical outcomes and beam quality correlations on skin cancer radiotherapy management in Mexico: A national institute experience: 2000-2013
        **Purpose**: To evaluate the outcome of radiotherapy for nonmelanoma skin cancer of Mexican population in terms of the radiation therapy modality received and local relapse-free survival. To show the cost-effectiveness benefit of kV therapy compared to linac based electron therapy.**Introduction**: Nowadays non-melanoma skin cancer (NMSC) is the most frequent malignant disease. Radiotherapy (RT) is a useful noninvasive alternative for some types of NMSC. It represents a valuable method for a minority histologically confirmed NMSC, in patients older than 60 years, where the patient’s medical conditions contraindicate surgery procedures, or if the patient refuses surgery or if surgery would result in unacceptable morbidity. We summarize the Mexican population epidemiological data of NMSC patients of thirteen years from a main reference cancer center of Mexico, Instituto Nacional de Cancerología (INCan). RT modalities for NMSC are brachytherapy (BT), superficial x-ray (ST), electron beam (ET) and orthovoltage radiotherapy (OT). We studied the role of different RT modalities mainly kV therapy (ST/OT) vs ET or a combination of different beam qualities.The use of kV units for RT in Mexico has been decreasing in last decades. Nowadays only 6 kV units are installed, 3 in private hospitals and 3 in public hospitals as IMSS (recently in disuse), INCan (now in disuse) and INCMNSZ (recent acquisition and operation). On the other hand, linear accelerators with a wide range of high energy (MeV) electron beams (26 units) are the choice of most facilities for treating superficial tumors including NMSC. The main goal of this study was to compare the efficacy, considered as overall survival (OS), disease-free survival (DFS) and recurrence-free survival (RFS) in terms of the quality of radiation beam utilized. A simple cost-effectiveness study was carried on as well.**Material and Methods**: We made a retrospective chart review of RT management on NMSC on a period of 13 years at the INCan. A total of 1224 patients treated with RT (palliative, radical or post-surgical intention) during 2000 to 2013 for NMSC were collected. Patient data included demographics (age at treatment date, gender, occupation, histology, surgical treatment, zone and lesion diameter). The median age was 72 years and 56% were female patients. Most patients (57%) were treated with kV therapy, the rest with ET (23%) and a combination of Co-60, electron and orthovoltage beams (20%). 24.1% of patients were treated with surgery, followed by RT and 67.2% were treated only with RT. We compared two groups of patients those who were treated with kV therapy and those treated with ET. All patients were treated with one single electron beam (4-6 MeV) in a Varian Linac or kV photon beams (50-200 kV) in a Gulmay kV unit. Radiotherapy data included the total absorbed dose (30-70 Gy) and fractionation scheme (10-35 fractions). The mean operational costs of 15 fractions in 2015 were $$4,448.00MXN and $17,751.30MXN for kV and ET, respectively. We studied the success/fail according to local failure and survival rate. U-Mann Whitney and Chi2 tests were used in order to find independency and correlations between groups. Kaplan-Meier curves were obtained for estimation of overall, disease-free and recurrence survival. Multi variate analysis was made also in order to analyze other factors contributing the outcome such as surgery. The statistical analyses were performed using v.23 of IBM SPSS Statistics software.**Results and conclusions**: The mean follow-up was 48 months. Population balance in terms on histological subtype were 75% basal and 30% epidermoid. There are few reports illustrating the outcomes of RT for NMSC. Our review includes a heterogeneous sample of beam quality management and it could be the first one in our country. We found a significant correlation (chi2 test, p<0.03) when we compare kV vs. ET in terms of clinical outcomes. The test of equality on free-recurrence survival distributions for different levels of RT modality had a significant result (Log-Rank Mantel-Cox p=0.019) with a best median of 15 months for kV therapy (12 months for ET and 9 for ET+kV). This finding suggests that the kV therapy should be the best decision for RT in NMSC. Moreover, our simple analysis comparing the costs and benefits of each modality enhance this conclusion, being the cost of ET triple expensive than kV therapy. Our finding suggests that keeping and increasing kV units in our country is necessary for a not cure rates reduction alternative. It is important to recognize that this simple technology is allocated to treat superficial lesions and discharge a linac machine for more complex and costly treatments.
        Speaker: Evangelina Figueroa-Medina (Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (México))
      • 18
        The past, present and future directions of radiotherapy in Asia: linking technology and the fight against cancer
        Introduction Asia is a heterogeneous and diverse continent having a population of 4.2 billion at present. The total incidence of cancer cases in Asia is 6.7 million which is almost 48% of the global incidence. In the 2015 statistics from a survey done by the Federation of Asian Organizations in Radiation Oncology (FARO), approximately 1.6 million cancer patients per year are being treated with radiotherapy from the 11 participating Asian countries. There are 7,984 radiation facilities in the FARO region with an estimated 200 cancer patients treated annually per radiotherapy facility. Currently, among the radiotherapy equipment being used, there are 564 cobalt-60 teletherapy, 3405 linear accelerators (LINAC), 1,671 2-D simulators, 1301 CT simulators, 4,001 treatment planning systems, 29 LDR and 978 HDR brachytherapy units. As the cancer burden is estimated to increase to 10.7 million in 2030, radiotherapy should meet this growing demand by improving accessibility, availability and support for these advances in technology.   Methodology Radiotherapy developed over 4 major eras: Discovery Era (1895-1925’s), Orthovoltage Era (late1920’s–1950), Megavoltage Era (1950-1985) and Computer-Assisted Era (1996-2012). The future is the Ion Beams Era with the development of proton and carbon ions. These advancements in technology have the primary goal of delivering high doses of radiation in order to target the tumor while minimizing doses to the surrounding normal organs at risks. This results in better tumor control, decrease in local failure rates, improvement in survival and improvement in the quality of life.   Current trends and technological advancements in Asia include: Stereotactic Radiosurgery (SRS), Stereotactic Body Radiotherapy (SBRT/SABR), Image-Guided Radiotherapy (IGRT), Image-Guided Brachytherapy (IGBT), Intraoperative Radiotherapy (IORT), Proton Beam Therapy and Carbon-Ion Radiotherapy. Many countries in Asia have started to use these or are already utilizing highly-advanced technologies in radiotherapy. Different local and regional radiation oncology societies such as JASTRO, SEAROG, Tri-lateral, FARO, etc, together with other international organizations like IAEA, ASTRO, ESTRO, are establishing linkages in order to improve the current state of radiotherapy in Asia through education and training, development of practice guidelines, research, and quality assurance programs. International cooperation and networking is important in conducting these activities primarily for the best interest of our patients. Conclusion Therefore, radiotherapy in Asia continues to evolve in order to address the demands of the growing cancer burden. Treatment-related toxicities are important issues that need our attention. Socioeconomic factors in an ever-increasing population are adding to the complexities of the cancer problem in the region.  Other important components in the fight against cancer include prevention, screening, and collaboration with a multi-disciplinary team of surgeons, medical oncologists and other related specialists. Strategic and concrete planning is necessary in order to assure the availability of these advancements in every place in Asia.
        Speaker: Miriam Joy Calaguas (Jose R. Reyes Memorial Medical Center-Department of Radiotherapy, Philippines)
    • Tuesday morning - Poster Presentations - Screen4
      Convener: Mr Oleg Belyakov (IAEA)
      • 19
        Automated treatment planning system commissioning: error reduction and improved efficiency for low and middle income countries come Countries
        In this work we propose standardization and automation of treatment planning system (TPS) commissioning for the purpose of error reduction, improved efficiency, and cost savings. This “new era of automation” is relevant and necessary given the global call-to-action for improving access to and investment in radiotherapy facilities for underserved populations in developing regions worldwide. As new treatment centers with limited resources are brought online, the global medical physics community will benefit from our proposed automated commissioning process that utilizes an application program interface and preloaded CPU with standard premodeled beam data, digital phantoms, and automated commissioning test suite to streamline verification testing and benchmark for ongoing QA. Current conventional procedures for treatment planning system commissioning are compared to the proposed automated commissioning process and assessed for potential risks and failures.
        Speaker: Amy Wexler (University of Missouri - Columbia)
      • 20
        Status of Radiotherapy and results of TLD postal dose quality audit in Ukraine
        Radiation therapy (RT) is one of the main treatment modalities for cancer patients. The effectiveness of radiation therapy depends on highly specialized equipment, the accuracy of delivery of absorbed dose to target tumor and staff qualification. The population of Ukraine is approximately 43 million. According to Ukrainian Cancer Registry statistics (Bulletin № 17, 2016) there were 125 424 new cancer cases registered in 2015. Crude incidence rate was 345.9 per 100 000 of population (356.8/100 000 males and 336.5/100 000 females). Currently, there are 53 Oncology сenters in Ukraine with radiotherapy equipment including four private Oncology clinics. The information about status of radiotherapy in Ukraine has been collected by the IAEA's annual survey DIRAC for all Ukrainian radiotherapy departments through National Coordinator – Grigorev Institute for Medical Radiology (IMR). The summarized data on radiotherapy equipment is presented. There are 103 teletherapy units in radiotherapy departments, including 80 Cobalt units (Co-60 radiation source) and 23 linear accelerators. Currently 45 Cobalt units (56.3 %) are in use for about 20 years or more and only 23 units (28.8 %) – less than 10 years. More than 50% of Cobalt radiotherapy units have the radiation sources Co-60 with the lifetime more than 10 years. There are also 42 brachytherapy units (6 units with Ir-192 source and 36 units with Co-60 sources) in Ukraine. Nine of them are not operational due to the absence of radiation sources. There are 36 CT and 5 conventional (X-ray) simulators in use. In total 18 radiotherapy departments are operation without simulators. There are 60 treatment planning systems (TPS) in radiotherapy in 35 Oncology centers (66 % of total). In the remaining 34 % oncology centers the dose calculation for patient irradiation is still performed manually. One of the ways to detect possible errors of the delivered dose in radiotherapy is to conduct independent external audits of the dose calibration quality for radiation beams. Ukraine participates in IAEA/WHO TLD postal audit of dose calibration quality for radiotherapy beams since 1998 (IMR – National Coordinator). During the period 1998-2015 the 48 Oncology Сenters took part in IAEA/WHO TLD -audit. A total number of checked radiation beams were 356 (15-25 beams per year). The results of the audit showed that about 25-30% of teletherapy units exceeded the 5% acceptance error limit. According to the national survey of radiotherapy departments the clinical dosimetry carried out not in all departments due to absence of modern dosimetric equipment, irregularly maintenance of teletherapy machines and low qualification of staff. In the framework of National TC-Project UKR/6/010 “Developing and Implementing a National Quality Control System by Strengthening the Knowledge and Capacity of Medical Physics at Radiotherapy Departments” (2012-2013) there were three training workshops organized for medical physicists of Oncology сenters: the two workshops on topic - Radiotherapy Practice at the Oncology (Clinical dosimetry) and one on topic - Commissioning and QA of Treatment Planning Systems. Also 25 complete sets of the equipment for clinical dosimetry were provided for radiotherapy departments of Regional and Municipal Oncology Hospitals of Ukraine under this IAEA TC-project. After IAEA technical support (training of medical physicists, implementation of International Code of Practice TRS № 398, and the use of modern clinical dosimetry sets) the results of TLD-audit in 2014 demonstrated the positive impact on improvement of the quality of clinical dosimetry in RT departments. The limit of acceptance error 5% was exceeded only for two teletherapy units (about 6% of total number audited units). The annual DIRAC survey of radiotherapy departments gives a possibility to monitor and assess the situation regarding equipment and staff in RT departments of Ukraine. Unfortunately at present the level of radiotherapy facilities is not sufficient for quality treatment for patients requiring radiotherapy. The main priority needs of radiotherapy departments in Ukraine identified through DIRAC survey and TLD-audit include are: replacement of radiation sources for Cobalt radiotherapy units; modernization of equipment using for radiotherapy – CT simulators and treatment planning systems; creation and implementation of a National Protocol to determine the absorbed dose in the external beam radiotherapy and permanent training of medical staff including medical physicists.
        Speaker: Tetiana Pidlubna (State Clinical Hospital Feofaniya)
      • 21
        Challenges and solutions of establishing advanced radiation oncology services in low and middle income (LMI) countries
        Purpose: To address the challenges that face LMI countries (LMIC) and how radiation oncology service (ROS) professional; medical physicists (MPs) and radiation oncologists (ROs), from 5 different LMIC practically overcame these challenges. Challenges and solutions: The multiple clinical and administrative challenges in our LMIC are a result of either lack of or insufficiency in the following 4 categories: 1] Number of qualified ROS professionals, 2] Academic education and clinical training, 3] National regulations including official recognition of the ROS professions, 4] Availability of modern equipment and required maintenance. The first two are most important from clinical point of view, whereas the remaining two show the level of maturity and awareness of the ROS professions in the country. To address challenges in categories#1 and #2, several LMIC presented in this study have resorted to collaborative agreements with reputed regional or international cancer institutions. Examples include the agreements between MD Anderson Cancer Center (MDACC) with each Jordan’s King Hussein Cancer Center (KHCC) and Egypt’s National Cancer Institute (NCI); between Zhianawa Cancer Center (ZCC) and West Virginia University and between King Hamad University Hospital (KHUH) and Turkey’s Erciyes hospital. These agreements result in implementation of clinical services and treatment techniques as well as local staff training. Regional collaboration among LMI institutions is also sought after; as an example the collaboration between Jordan’s KHCC with each Egypt’s NCI and Iraq’s ZCC in which MP and RO experts are exchanged. In addition to institutional agreements, networking with regional or international experts is also used to augment certain aspects of clinical service, such as ZCC using King Faisal Specialist Hospital and Research Center (KFSH&RC) MP experts and KFSH&RC using MP experts from McGill University. The second category poses a more difficult challenge. Currently, the Asia part of Arabic countries along with Egypt, a population of approximately 240 million, have few clinical training programs. There is a handful of RO residency programs available one in each country (Egypt, Iraq, Jordan, Lebanon and Saudi Arabia). For MPs, the situation is worse with one residency program in Saudi Arabia. Almost all physicists in our region get on-the-job-training. To mend this severe lack of training, extensive clinical workshops are continuously conducted in the region. The nature of these workshops is hands-on training and each focuses on a particular clinical aspect. Regional countries have adopted a synergistic approach in which each contributes its experts in particular field to train others. These workshops serve as a main source of knowledge transfer and training. To add another layer of challenge, national regulations and recognition of the medical physics (MP) profession is lacking, with the exception of Egypt and Saudi Arabia (SA). In the former the MPs have an official title of “specialist scientist” while in the latter the MPs are fully recognized with preferences for board certification, though itself lacks a board certification scheme/body, even while it hosts the region’s only residency program. It is interesting that neither specialties, MP or RO are available among the list of specialty studies (thirty in total) in the Arab Board of Health Specializations, Due to lack of national guidelines, large institutions in LMIC are left to develop their own QA protocols adopted from other bodies such as AAPM, IAEA and ESTRO and then pass them on to smaller institutions through training workshops and regional expert visits. Results: The implementation of the above solutions namely agreements with regional and international institutions and reaching out to individual experts have resulted in many success stories; implementation of SBRT, SRS, VMAT and IMRT techniques in most centers, and improvement in on-going services such as pediatric oncology and brachytherapy in others. The most important impact of these outreach efforts is in regards to training and education of the staff. Graduates of the handful RO residency programs are now practicing in many local LMIC, including Bahrain, Egypt, Palestine (Gaza Strip), Iraq, Jordan, Saudi Arabia and one in the UK. The single MP residency program has graduates working in Jordan, Oman, Saudi Arabia and Yamen. Conclusion: There is no one-single global solution in establishing safe state-of-art treatment techniques in LMI countries. However, we found that the one successful and cost-worthy solution adopted by professionals in the 5 countries presented in this study is networking and outreach to regional and non-regional institutions and individual experts. LMI states have to adopt a synergistic solution in which each one benefit the other where expertise is lacking. Leading regional institutions should shoulder the burden of passing on the knowledge and provide for training for others. National guidelines and recognition of the ROS professions by the local authorities remain the big challenge that require efforts on the political and global scale.
        Speaker: Belal Moftah (King Faisal Specialist Hospital and Research Center)
      • 22
        Broken machines or broken systems – The ugandan experience, on accessing/maintaining radiotherapy services, in low and middle-income countries
        Introduction: By 2020, about 70% of new cancer cases will occur in LMICs. According to DIRAC, 27 African countries have no radiotherapy and only 26 countries have. The expected number of new cancer cases in Africa in 2015 was 700,000. Over 50% of cancer patient’s benefit from radiotherapy alone or in combination with surgery or chemotherapy, implying that over 350,000 would require radiotherapy. Common malignancies including cervical, head&neck, etc mainly presenting in advanced stages – are incurable without radiotherapy, especially in the absence of highly-specialized surgery and chemotherapy. Despite this enormous need, access to radiotherapy is inadequate for most cancer patients and machine down-time remains high. The Machines per Million Population (MMP), in LMICs range from 0.1-0.3, which is very low compared to developed countries (4.0–6.0). Case in point Currently, Uganda has no functional external beam radiotherapy services. The single Cobalt-60 machine, installed at Mulago in 1995 stopped functioning beyond repair in March 2016, a feature that attracted international attention. The number of new cancer patients worked on this machine gradually increased from 292 in 1995 to 1920 in 2015; treating a total of 25,465 patients (≈ 600,000 sessions) over the 21 year period. In comparison to a Linac, that can treat 312500 - 375000 sessions. Efforts for the expansion of radiotherapy services in Uganda started as early as 2000. It was planned to have 2 more EBRT units at Mulago and 3 centres in regional hospitals. However, due to budgetary constraints, this expansion program was postponed every year until it was dropped. Plans for the replacement of the broken Cobalt unit started in 2005, three years after a major overhaul that included source exchange. The department made several consultations and expert missions were sought from IAEA: (1) Assessment of Cobalt-60 machine and current capabilities in the Department by Jan Karl Hough December 2008 (2) Design and construction of a bunker for expansion of radiotherapy services by Frederic Johannes Lange, December, 2011 Despite all these recommendations, there were no tangible outcomes as far as expansion of radiotherapy services in the country. There were numerous administrative/managerial factors that hindered progress in radiotherapy, e.g. (1) Between 2010 and 2011, the Mulago hospital administration identified a contractor to construct a new bunker, procure and install a new Cobalt-60 machine. However, before this process was completed, there was a change in administration in April 2011 that resulted in halting the process. (2) Between 2011 and 2013 the new administration came up with a relocation plan of the department, worked on designs for the radiotherapy bunkers (2 EBRT/1 HDR and other auxiliary facilities). However, before the process was concluded, the department was transferred administratively to be under the Uganda Cancer Institute (UCI), in June 2013. This was in fulfilment of PACT recommendation, with the aim of creating an integrated cancer treatment centre. The UCI administration noted inaccuracies with the designs and the process was halted, however construction started in June 2016. The above scenarios are characteristics of system breakdown, which in this context is a collapse of responsible authorities to perform, organise, maintain and support services following a fixed plan or set of rules. Government owned facilities are more affected than those that are privately owned. Irabor et al (2016) reported the stagnation of radiation oncology resources in Nigeria. It was reported that as of Jan 2016: only 2 of the 9 commissioned radiotherapy centres were functional, that 2 of the 5 linear accelerators installed in 2010 were not functional and that there were fewer brachytherapy (HDR +LDR) units than in 2001. The blame was put on the Nigeria economic and political climate, lack of trained servicing engineers, procurement of equipment with minimal input from end users and no servicing contracts. Johanna et al (2016) also reported on how the challenges of resourcefulness were affecting radiotherapy in the Philippines. The Kenya’s main hospital has a functional Cobalt-60 unit where the source has not been replaced since its installation, over 17 years ago. The Zambia’s only radiotherapy centre installed a Cobalt-60 unit in 2013 that is not yet utilised due to procurement mishaps – unfortunately the source is decaying. Conclusions: Machine breakdown, downtime and decommissioning are some of the many events in a radiotherapy department. There is need for support for partnership and systems of care, more vigorous mechanisms to ensure that radiotherapy is part of planning for cancer care and control in LMICs. There are essential requirements that need much bigger budget, staff and mandate to ameliorate the numerous logistical complexities of acquiring and maintaining radiotherapy services. The lessons from Uganda and other LMICs emphasize the fact that it’s not that machines break, but systems do.
        Speaker: Awusi Kavuma (Uganda Cancer Institute)
      • 23
        Radiotherapy utilization in developing countries: an IAEA study.
        Radiotherapy utilization in developing countries: an IAEA study Eduardo Rosenblatt, Elena Fidarova, Eduardo H. Zubizarreta, Michael Barton, Glenn W. Jones, William J. Mackillop, Lisbeth Cordero, Joel Yarney, Gerard Lim John V. Gan, Valentin Cernea, Susana Stojanovic-Rundic, Primoz Strojan, Lotfi Kochbati, Aldo Quarneti Background The planning and monitoring of national radiotherapy services requires a thorough knowledge of the national cancer epidemiology profile, the radiotherapy utilization (RTU) rates and a realistic future projection of these data. Previous studies have established RTU rates in high income countries. Methods The IAEA conducted a project to investigate the optimal and actual RTU rates in 9 middle-income countries. The aim was to estimate the actual RTU rate and compare it with the optimal RTU in each country to estimate the gaps in service provision. The countries selected for the study were Costa Rica, Ghana, Malaysia, Philippines, Romania, Serbia, Slovenia, Tunisia and Uruguay. Optimal RTU (oRTU) was determined following the epidemiological evidence-based method using cancer incidence data from Globocan-2012 and radiotherapy indication trees from the CCORE group. The actual RTU (aRTU) rates were calculated dividing the total number of new notifiable patients treated with radiotherapy in 2012 by the total number of cancer patients diagnosed in the same year. An analysis of the characteristics of patients and treatments in a series of 300 consecutive patients receiving RT shed light on the particular patient, diseases profile and techniques used in the participating countries. Results The calculated median oRTU rate for the group of 9 countries was 52% (Table 1). There was a difference of 9% between the lowest oRTU in Costa Rica (47%) and the highest in Tunisia (56%). This was due to variations in the incidence of some cancer types treatable with radiotherapy that have a lower incidence in Costa Rica than in Tunisia. The aRTU rate for the 9 countries was a median of 28% with a range from 9% (Ghana) to 46% (Tunisia). The results show that the actual proportion of cancer patients receiving RT is lower than the optimal RTU with a rate difference between 10% (Tunisia) and 42.7% (Philippines). The median percent unmet need was 47% (range 18-82.3%). Patient’s mean age at diagnosis was 55 years and the gender distribution m/f was 36/64%. Mean delay caused by the medical system was 280 days, and mean delay caused by internal center’s procedures was 73.5 days. 67% of patients were treated with palliative, and 33% with curative intent. A mean 54% of patients had previous surgery and 21% received concomitant chemo-radiotherapy. From the RT technique viewpoint and out of the total of 2549 patients analyzed, 49.1% were treated with 2D, 42.6% with 3D, 3.2% with IMRT and 4.9% with other techniques. 16% of patients were treated with hypofractionated regimens. The median re-irradiation rate was 11% and the most frequent irradiated sites were: pelvis (27.3%), breast (26.8%), head-and-neck (12.8%), CNS (11.8%) and “other” (11.1%). Conclusions The optimal RTU rate in this group of middle-income countries did not differ significantly from that previously found in high income countries. The actual RTU rates were consistently lower than the optimal, ranging from 9% to 46%. The gap between optimal and actual RTU rates in these 9 middle-income countries as well as the calculated percent of unmet need could be explained by obstacles in access to existing RT services and other factors. National radiotherapy services should be rationally planned in order to improve access to RT.
        Speaker: Eduardo Rosenblatt (IAEA)
    • Tuesday morning - Poster Presentations - Screen5
      Convener: Mr Oleg Belyakov (IAEA)
      • 24
        Challenges and solutions, advantages and disadvantages of launching 1st 3-Dimensional brachytherapy in a developing war-torn country (Iraq) using Co-60 High Dose Rate (HDR) source
        Background: Brachytherapy (BT) is a well-known part of radiotherapy services for cancer treatment globally for almost a century and can be generally of low dose rate (LDR) or high dose rate (HDR) via using different radioactive isotopes. This service was used to be in Iraqi radiotherapy institutes till 1990s when the wars and embargo started to affect all the aspects of life. All the patients who were in need for this modality of treatment had to travel abroad, incurring great cost as they did so. Recently, this service became available again free of charge inside Iraq. In this paper, we will describe the challenges and solutions, advantages and disadvantages of launching the 1st 3-Dimensional BT in a developing war-torn country using Co-60 HDR source. Methods: Zhianawa Cancer Center (ZCC), a public radiotherapy facility established in 2009 in Sulaymaniyah city – Kurdistan – Iraq, wanted to add BT to the list of treatment modalities offered. We had to choose between delivering BT through LDR or HDR in addition to choosing the type of source. All while trying to overcome multi-layers of challenges. Results: 1. The choice of the HDR after-loader over LDR was made for two reasons: HDR delivers similar clinical outcome as LDR but without the hassle of hospitalizing the patient. An important challenge to keep in mind as our facility is a stand-alone RT clinic and lacks the required in-patient care for the LDR implants. 2. Once the choice of after-loader was made, we had to look at the type of source to buy. The popular iridium, Ir-192, vs the more recent Cobalt, Co-60, source. Co-60 has a half-life that is about 26 times that of Ir-192, 5.26years vs 74 days. This means that we have to worry about the difficulties and the red-tape of exporting a radioactive material once every few years. The bureaucratic delays and multi-layers red tapes that are abundant the public health system in Iraq, makes purchasing equipment very difficult. Other advantages of using a long-lived source is less transport difficulties and less need for performing source exchanges and hence acceptance testing. 3. The center does not have a Well-chamber to measure the source activity when it arrives, so we requested that the appropriate set of quality assurance tools be delivered with the machine. We were surprised to receive the Krieger Phantom. The vendor delivered the Co-60 after-loader and its control and planning systems, along with that we received an electrometer, a 0.6cc ion chamber and the Krieger Phantom. As this phantom is not very popular outside Germany, we had to contact many experts and search many protocols (some in German) to know how to use the phantom for source measurement. This alone, took a good part of 2 years. 4. Two decades of war and embargo had led to a severe lack of local expertise in brachytherapy physics and clinical services. To overcome this situation, we setup multiple in-house workshops and training courses, experts from the region and internationally provided hands-on training for our staff. To gain enough knowledge and to be confident, this part also took some 2 years. A regional expert was present during the treatment of the first HDR patient. The machine was available on site in 2013, however, the first patient was treated in mid-2016, and since we have treated 10 patients for gynecological tumors, each for 2-5 sessions. Conclusions: In spite of the difficult challenges, BT was successfully re-started in Iraq. As of now, our center in Kurdistan is the only one delivering such service to the entire population of Iraq free of charge. In this synopsis, challenges and solutions, advantages and disadvantages of using the Co-60 HDR BT were explored. The authors believe that this piece of knowledge might be of interest to the colleagues in the international communities who are facing similar challenges.
        Speaker: Hawbir O. Ghafour (Zhianawa Cancer Center)
      • 25
        Availability of radiotherapy in Africa: past and present of an unsolved problem
        Purpose/objective To present data on availability of megavoltage (Mv) units (cobalt machines (Co) and linacs) in Africa from 1991 to 2015 and the additional resources needed to reach full capacity, including a cost analysis. Material and methods The list and income classification of countries were taken from the World Bank, Country and Lending Groups, 2017 fiscal year [1]. Data on population, number of cancer cases per country, and number of cancer cases for each cancer site was obtained from GLOBOCAN 2012 [2]. The number of radiotherapy courses needed to treat all patients with an indication for radiotherapy was calculated using the methodology form the Collaboration for Cancer Outcomes Research and Evaluation (CCORE) [3,4]. Data on availability of radiotherapy (RT) equipment was obtained from the IAEA Directory of Radiotherapy Centres (DIRAC) [5]. For the cost analysis we used an internally produced Excel sheet with data from December 2013. 51 countries were included in the analysis. Historical data was obtained from different published data [6,7,8,9]. Most of the other variables used for the calculations were taken from the GTFRCC report [10]. Results The population in Africa is 1.07 billion, with a weighted GNI per capita of US$ 2,086, and it is calculated that 438,000 cancer cases need radiotherapy annually. Mv units were 103 in 1991 (71 Co and 32 linacs), 155 in 1998 (93 Co and 62 linacs), 277 in 2010 (88 Co and 189 linacs), 278 in 2013 (84 Co and 194 linacs), and 291 in 2015 (86 Co and 205 linacs), representing an increase of 283% in almost 25 years (fig 1). The proportion of Co units decreased from 69% to 30% in that period (fig 1). A total of 813 Mv units are required to treat 438,000 cancer patients needing RT. Only 149,000 can be treated with the installed capacity, which represents a coverage of 34% of the needs. Low income countries can only treat 4,800 cases, 3% of the needs.
        Speaker: Eduardo Zubizarreta (Section Head ARBR - NAHU - IAEA)
      • 26
        Radiotherapy in Nepal: a view from medical physics
        In October 2016 a team comprising three Radiation Oncologists and one Medical Physicist made a visit to Kathmandu, Nepal. The purpose of the visit was to deliver a Radiotherapy Treatment Planning course to trainees, Consultant Radiation Oncologists and Physicists. Visits were made to three radiotherapy centres in Kathmandu : Bir Hospital Kathmandu (1 Co60), Kathmandu Cancer Centre(1 linac) and the Nepal Cancer Centre (1 linac). This paper provides a snapshot of the challenges facing the delivery of Radiotherapy services in Nepal. There is a shortage of trained Medical Physicists. Each of the centres visited has only one Physicist for all treatment planning and machine related activities. The staff are enthusiastic, eager to learn and, like physicists worldwide, aspire to deliver high quality treatment using the latest technologies. However, the lack of support in both human and material resources presents significant challenges to delivering safe and timely radiotherapy. This results in a large workload for individuals and limits the process and workflow to a single person environment. Due to a lack of access to healthcare most treatments are palliative and, while cancer incidence is expected to rise, Radiotherapy is not a public health priority in Nepal. The expansion of services are only taking place in the private sector. The course was delivered in two sessions to staff from the three centres. The topics covered included: the physics of photon and electron beams, 3D conformal planning and plan evaluation, planning volumes, contouring (H&N and cervical), breast planning, Quality Assurance, protocols and guidelines.
        Speaker: Paul Hill (Cork University Hospital, Ireland)
      • 27
        Small cell lung cancer: A retrospective study of 70 cases
        Small cell lung cancer: A retrospective study of 70 cases Background: Small-cell lung carcinoma (SCLC) is an aggressive form of lung cancer. Therapeutic strategies are chemotherapy (CT), radiotherapy (RT) and supportive care. This study aims to investigate the clinicopathologic characteristics, therapy methods and prognosis of SCLC. Methods: We conducted a retrospective study of 70 cases of SCLC collected in the department of medical oncology of Salah Azaiz institute in Tunis over a period of 6 years (2008-2013) Results: The study population comprised 66 men and 4 women. The median age was 58 years. All patients were smokers. At presentation, the vast majority of patients were symptomatic. Pathological diagnosis was obtained essentially by the performance of bronchoscopic biopsy .It revealed a lung small cell neuroendocrine carcinoma .50℅ of tumors were immunoreactive for TTF-1 , 90℅ for keratin and 73℅ for EMA .Tumors cells stained positively for markers of neuroendocrine differentiation including chromogranin A , synaptophysin and CD56 . The disease was metastatic in 75℅ of cases. According to the VALCSG classification ,the tumor was staged as limited-stage disease in 15 cases and extensive-stage disease in 55 cases .13 patients received a curative –intent CT : 10 patients had induction CT before RT and 3 patients had concomitant radio-chemotherapy .Etoposide with cisplatin (EP) was the used regimen. The median overall survival (OS) in the limited-stage disease group was 16 months. 81℅ of patients with extensive-stage disease received palliative chemotherapy. The main regimens were EP, etoposide with carboplatin and CAV (cyclophosphamide, doxorubicin and vincristine). 17 patients received second line CT. Only 6 patients had third- line CT. A whole brain RT, thoracic RT, analgesic RT and RT of spinal cord compression were administrated in respectively 35℅, 28℅, 11 ℅ and 6℅ of cases. The median OS in this group was 9.3 months .91℅ of patients received morphine.30 ℅of patients were oxygen dependent. Evacuative thoracentesis was performed in 24 ℅of cases. The median overall survival of the study population was 10.32 months. Conclusion: Small cell lung cancer has poor prognosis. Developing prognosis biomarkers and experimenting new agents are needed to improve outcomes.
        Speaker: Hajer Kammoun (Institut Salah Azaiez de Cancerologie, Tunis)
      • 28
        Two Dimensional (2D) vsThree dimensional (3D) treatment planning in Paediatric Radiation Oncology. Less technology can be acceptable?
        Introduction: In our country and others Low Income Countries (LIC) the difficulty to access technology cause delay in Radiotherapy (RT) and decrease survival. Children have their treatments delayed especially if their treatments include 3D plannings. We thought that could be educative to evaluate when 2D plannings could be used safely in paediatric radiation oncology cases. During a project supported by IAEA –PRON- Optimization of radiotherapy in low resource settings: pediatric cancer patients”– we compared 2D and 3D plannings in patients that had agreed to participate and/or performed also 2D planning for any reason. The goal was compare inside of the same patient the two different modalities 2D vs 3D to detect in which situations would be acceptable to perform a 2D planning. Methodology: All patients were planned at the AccuityVarian digital simulator using planar RX (2D). The physician defined fields and protections based in bone marks and/or Computed Tomography (CT), magnetic resonance image (MRI) to evaluate the target, margins and OAR. All the 2D plannings were performed first. After the procedure at the simulator, all the patients were also submitted to CT planning and all the structures (GTV, CTV, PTV and OAR) were contoured by the same physician in the TPS. The patients were then planned to 3D treatement. They were planned using a TPS Eclipse Varian to calculate the 2D and 3D plannings. The fields and MLCS defined by the physician at the Simulator were copied to the CT of the patients and the 2D planning reconstructed and calculated in TPS. The comparison of the 2 plannings (2D vs 3D) were performed at the TPS and the doses to the targets and OARs analyzed using dose volume histogram data. Statistic analysis were done using Wilcoxon Non parametric Test. BioEstat 5.0 software - p≤ 0.05. Results: We studied 28 patients, 15 male, 13 female, (18 months to 21 years old), mean age 8,5 years. We had different cases and sites: Cranio-Spine Irradiation (CSI)(4) leukemia (Brain to C2-3 irradiation) (3); lymphoma (2) , wilm´s tumor(5)(whole abdominal irradiation (WAI+ boost) (3), Whole lung irradiation WLI (2); combined sites (1); Soft tissue tumors (STT) (6): face (2) extremities (2), thorax (2), combined sites (2); Central Nervous System(CNS) tumors (8). We observed that: In CSI and Leukemia cases 2/7 (28,5%) of cases the cribriform plate was not well covered 70%vol with dose prescription, but the difference in coverage were not significant p = 0,06. The dose to the lens and eyes were increased in 3D plannings. The dose to the caudal extent of thecal salc was efficient in all the four patients. The dose to the kidneys were significantly reduced with 3D planning (volume 23Gy – decreased 40%). The coverage of CTV and PTV were not statistically significant different, p = 0,25. Lymphomas cases plannings – the dose to the GTV, CTV and PTV were similar however the dose to the lungs was increased in 2D plannings – V20 –50%, V15 30% V5 15%. Wilm’s tumor cases plannings to WLIand WAI followed by boost showed no difference in terms of target coverture between 2D vs 3D planning. The OAR doses were lower with 3D but not significantly different p = 0,056. Soft tissue tumor cases (STT) – STT face- The dose to the GTV were unsatisfactory, in general 20% lower than 3D planning. The doses to the OAR were in general increased with 2D in special optic nerves and optic chiasm. Dose to CTV and PTV was unacceptable 30 to 40%lower than 3D. The coverage of PTV and CTV was statistically significant better to 3DP = 0.034. STTs extremities – The coverture of GTV and CTV were acceptable in extremities but the PTV had lower doses 80% vs 93% coverture. The STT thorax planning showed the 20 to 30% lower coverture to CTV and PTV in and the OAR (heart nd lung) had increased doses with 2D. CNS tumors cases plannings showed the dose to GTV were lower with 2D but not significant p =0,64 mean dose to CTV and PTV were significantly better to 3D p = 0,04 and p = 0,02 respectively. Significant protection to optic chiasm was observed with 3D. Brain, temporal lobe dose were not significant different. Conclusions: Based in this cases. 2D plannings of WLI, WAI in Wilm’s tumor and STT of extemities are safe and acceptable, CSI and leukemia 2D plannings can be done relatively safe but with care to cribriform plate coverture. Plannings of STT face, STT thorax and lymphomas were unacceptable. The worst situation was the CNS tumors to perform 2D plannings.
        Speaker: Rosangela Villar (Centro Infantil Boldrini)
    • Session 3 - Global cancer challenges and role of RT M1


      Learning objectives:
      1. To identify the more relevant challenges in global cancer management
      2.To identify the role of radiotherapy in the global management of cancer

      Conveners: Mr Brendan Healy (International Atomic Energy Agency) , Dr Eduardo Zubizarreta (Section Head ARBR - NAHU - IAEA) , Ms Mary Gospodarowicz
      • 29
        Challenges in cancer control
        Speaker: Mrs Mary Gospodarowicz (Princess Margaret Hospital (Canada))
      • 30
        Sustainability of radiotherapy in LMICs
        Speaker: Mr Alfredo Polo (IAEA)
      • 31
        Innovating to meet the demand for RT
        Speaker: Mr David Jaffray
      • 32
        Reimbursement in HIC
        Speaker: Mrs Yolande Lievens (University Hospital Ghant (Belgium))
      • 33
        Auditing advanced technologies
        Speaker: Dr David Followill (MD Anderson Cancer Center)
      • 34
        Discussion, Q&A
    • Session 4 - DIrectory of RAdiotherapy Centres - DIRAC M1


      Convener: Dr Eduardo Zubizarreta (Section Head ARBR - NAHU - IAEA)
      • 35
        DIrectory of Radiotherapy Centers (DIRAC)
        Speaker: Dr Joanna Izewska (International Atomic Energy Agency)
    • Session 5a - Contouring Workshop (Lung cancer) M3


      Learning objectives:
      1. To learn how to contour the GTV and CTV in lung cancer
      2. To learn how to contour OAR in lung cancer

      Convener: Dr Billy Loo
      • 36
        e-Contouring Workshop: Lung Cancer
        Speaker: Mr Billy W. Loo
    • Session 5b - Paediatric RT M1


      1. To understand the particularities of pediatric radiotherapy
      2. To learn how to implement a pediatric radiotherapy programme
      • 37
        Paediatric medulloblastoma
        Speaker: Prof. Mohamed Zaghloul (Children's Cancer Hospital, Egypt &amp; National Cancer Institute, Cairo University)
      • 38
        Benefits of High Technology applied to Paediatric Radiation Oncology
        Speaker: Ms Rosangela Villar (Centro Infantil Boldrini)
      • 39
        Paediatric intraoperative electron radiotherapy: results and innovations
        Speaker: Mr Felipe Calvo
      • 40
    • Session 5c - Industry Lunch Symposium: Technologies in External Beam Radiotherapy M7


      Learning objective:
      1.To identify the latest technologies in external beam radiotherapy

      Convener: Mr Brendan Healy (International Atomic Energy Agency)
      • 41
      • 42
      • 43
      • 44
      • 45
      • 46
        Discussion, QA
    • Session 6 - Requirements for safe and effective transition to new/appropiate technologies M1


      Learning objectives:
      1. To discuss the need for a transition to new technologies
      2. To identify the basic requirements to make this transition safe and effective

      Conveners: Mr Belal Moftah, Dr Debbie Gilley (IAEA) , Dr Debbie van der Merwe (University of the Witwatersrand) , Mr Pierre Scalliet
      • 47
        Panellist - 1
        Speaker: Mr Pierre Scalliet
      • 48
        Panellist - 2
        Speaker: Prof. Jacob Van Dyk (Departments of Oncology and Medical Biophysics, Western University, London, Ontario, Canada)
      • 49
        Panellist - 3
        Speaker: Dr Debbie van der Merwe (University of the Witwatersrand)
      • 50
        Panellist - 4
        Speaker: Ms Mary Coffey
      • 51
        Discussion, Q&A
    • Session 7 - Health economics of cancer M1


      Learning objectives:
      1. To understand the basics of health economics of cancer

      Conveners: Mr David Jaffray, Dr Eduardo Zubizarreta (Section Head ARBR - NAHU - IAEA)
      • 52
        Health economics of cancer
        Speaker: Ms Yolande Lievens
      • 53
        Question and Answers
    • 3:30 PM
      Coffee Break
    • Tuesday afternoon - Poster Presentations - Screen1
      Convener: Mr Oleg Belyakov (IAEA)
      • 54
        High dose rate surface Brachytherapy for skin with Flap applicator. Technique and discussion of a case
        Introduction of the study: The Freiburg Flap from ELEKTA is a flexible mesh still surface mould for skin or intraoperative surface treatment. The mould can be easily adapted to any shape. It ensures a constant distance of the treatment catheter to the skin of 5mm for reproducible dosimetry, treatment channels are set 10 mm a part from each others. Cutter, flexible implant tubes are introduced in the Flap. The mould provides an excellent alternative for orthovoltage or electron beams treatment in case of superficial macroscopic tumor irradiation depth ≤ 1 cm or in case of microscopic disease with marginal limits. Methodology: We describe the technique of irradiation in one case treated in the department of Radiotherapy at the National Institute of Oncology in Rabat. This is a patient aged 66 years, operated for a T3 well-differentiated squamous cell carcinoma of the scalp. The resection was marginal at 1mm from the deep plan; hence the indication of adjuvant therapy with brachytherapy is retained. The tumor bed was delineated with ink on the surface with 0.5cm margin and radio-opaque wire is applied. The Flap applicator is fixed over an aquaplast base frame and shielding is used to make better contact. The target volume is delineated on the CT images and intended dose is prescribed to an approximate depth of 3mm from the skin surface. Treatment planning (reconstruction of catheters, prescription of the dose, activation of dwell positions and optimization to create conformal plan) is done on CT images with Treatment Planning System of ONCENTRA BRACHY .The plan is validated on 3D views and DVH tables. We used for treatment nine Cutter flexible implant tubes. A procedure of Quality Control has been followed for each tube before clinical use. It consists on checking the first dwell position with the source position simulator set, this value is the indexer that should be introduced on the TPS and this first dwell position must be checked with gafchromic films. The patient is treated with 6 fractions of 5Gy each, twice a week over two weeks. Results Low acute dermal reactions were noted, the patient will be followed 15 days after brachytherapy, 1 month and then every 3 months during 2 years. Conclusion Our initial experience with 3 dimensional topographic applicator skin brachytherapy is especially encouraging with an easier and safety use, an adaptative application for each fraction, feasibility for all sites and excellent dosimetric conformity.
        Speaker: Hanae Bakkali (Institut National d'Oncologie, Rabat)
      • 55
        Hypofractionated radiation for pediatric diffuse intrinsic pontine glioma (DIPG) is non-inferior to conventional fractionation: a prospective randomized trial including 222 children
        Background: Pediatric diffuse intrinsic pontine glioma (DIPG) remains for the last decades as a dismal disease though of the rigorous attempts to improve results through adding chemotherapy, immunotherapy or target therapy in different combination, scheduling and intensity to the already established conventional radiation therapy. We previously reported that hypofractionated radiotherapy, in a dose of 39 Gy in 2.6 weeks, had similar clinical end-results to conventional 54 Gy in 6 weeks. Aim of the work: to confirm the non-inferiority of hypofractionated to conventional fractionation in treating pediatric DIPG and to explore the optimum dose level for such treatment to achieve better overall (OS), progression-free survival (PFS) and toxicity profile. Methodology: Tow hundred twenty-two children fulfilling the typical clinical and MR imaging features of DIPG were randomized into 3 groups: 1. Hypofractionated 39 Gy in 13 fractions (300 cGy/fraction), 2. Hypofractionated 45 Gy in 15 fractions (300 cGy/fraction) and 3. Conventional 54 Gy in 30 fractions (180 cGy/ fraction). Results: The distribution of patients’ characteristics in the 3 groups were even and did not show any statistically significant differences. The median overall survival (OS) of all patients was 8.5 months (95% CI: 7.6 – 9.4) while the progression-free survival (PFS) was 6.8 months (5.9 -7.6). The median OS of the 3 groups (39, 45 and 54 Gy) were 9.6 (7.6 -11.6), 7.7 (6.2 -9.3) and 8.6 (7.3 – 9.9) months respectively. The 18-months OS for the 3 groups were 14.0 ± 4.7%, 14.5 ± 4.4% and 9.7± 4.3% respectively revealing non-inferiority of either hypofractionated group to the conventional group. Furthermore, the median PFS in the 2 hypofractionated (39 and 45 Gy groups) were 8.0 months (6.4 -9.6) and 5.8 months (4.8 – 6.9) respectively compared to 6.9 months (5.9 – 8.0) for the conventional group. These PFS results of either hypofractionated group proved to be non-inferior to that of conventional fractionated group. The toxicity profile was similar in the 3 treatment groups. Both median OS, PFS and the 18-months OS and PFS were not affected by the patient gender nor age. However, it was noticed that young patients (below 5 years old) had better treatment outcome (OS and PFS) though not statistically significant. Conclusion: Hypofractionated radiotherapy clinical outcome is non-inferior to conventional fractionation for the treatment of pediatric DIPG. It seems that no optimal dose level for hypofractionated radiotherapy of DIPG. These results may establish hypofractionated radiotherapy as the standard of care for such aggressive disease to minimize the burden on the child, the family and treating institution without jeopardizing the results of treatment including OS, PFS and toxicity.
        Speaker: Mohamed Zaghloul (Children's Cancer Hospital,Egypt & National Cancer Institute, Cairo University)
      • 56
        Dosimetric comparison of dose to contralateral breast in postmestectomy patients treated using different treatment techniques
        Purpose Postoperative radiotherapy significantly reduces the risk of loco-regional failure and improves disease-free survival. However, peripheral dose to the contralatral breast is cause of concern due to its higher radiosensitivity towards radiation induced second malignancy. The present study aimed to measure the contralatral breast dose from the post mastectomy radiotherapy (PMRT) using conventional asymmetric jaw and 3D conformal radiation therapy (3DCRT) treatment techniques separately. A comprehensive analysis of data of contralatral breast dose was made to determine methods if radiation could be delivered safely and effectively with a reduced contralatral breast doses. Materials and methods: Fifty breast cancer patients with post mastectomy were included in the study, which underwent external beam therapy on cobalt-60 teletherapy machine and linear accelerator machine. Patients were planned to treat to the chest wall (CW) to a dose of 50 Gy/ 25# with opposed tangents, Supra Clavicular Field. Of these, twenty five patients treated with PMRT on Bhabhatron-II TAW telecobalt machine using asymmetric jaws with conventional medial and lateral tangential fields were treated on alternate days. Rest twenty five treated on Siemens Oncor Expression linear accelerator using 3DCRT technique with medial and lateral tangential fields daily. The contralatral breast doses in assessed using optically stimulated luminescence dosimeter (OSLD) which was placed at the level of contralatral breast nipple prior to start of the treatment. The dose contribution was measured only for tangential fields; SCF doses were not included in the study. Results and discussions: The dose measured at the contralateral breast nipple for patients treated on telecobalt machine was observed between 114.25 to 193.12 cGy for total primary breast dose of 5000 cGy in 25 equal fractions which accounted to be 2.28-3.86% of total dose to ipsilateral breast while for the patients treated on linear accelerator the dose measured at the contralateral breast nipple was observed between 73.75-171.00 cGy for total primary breast dose of 5000 cGy in 25 equal fractions which accounted to be 1.47-3.42% of total dose to ipsilateral breast. The cause of higher doses observed in patients treated on telecobalt machine is due to fact that the beam modification was achieved with asymmetric jaw in the cobalt-60 teletherapy machine while in linear accelerator the beam modification was achieved with the help of multileaf collimator (MLC), which resulting in a reduced scatter dose to contralateral breast dose. Further, it was observed that the maximum contribution of contralateral breast dose was due to medial tangential (MT) fields, which was about two times higher than dose contribution due to the lateral tangential (LT) field. Conclusions: Though the use of MLC in 3DCRT treatment showed acceptable coverage of PTV provides excellent normal tissue sparing with a reduced dose to contralatral breast. However, MLC does not seem to be suitable for PBRT with unacceptably tight margins of PTV. The use of telecobalt machine with asymmetric jaws is a good choice for PMRT considering socioeconomically factors, at a cost of slightly higher dose to contralatral breast.
        Speaker: Gourav Kumar Jain (Department of Radiological Physics, SMS Medical College & Hospital, Jaipur)
      • 57
        Role of radiotherapy in multiple myeloma; a multicentric experience
        Background: Multiple myeloma (MM) is hematologic malignancy characterized by the accumulation of malignant plasma cells in the bone marrow. Recently, MM remains uniformly fatal with a median survival of approximately 50 months after diagnosis. MM is extremely susceptible to radiation treatment and targeted radiotherapy including bone-seeking radiopharmaceuticals, monoclonal antibodies conjugated to radionuclides (radioimmunotherapy), and radiotargeted gene therapy using recombinant oncolytic viruses (radiovirotherapy) now offers a new paradigm to target this systemic malignancy. Palliative irradiation of osteolytic lesions is a considerable component in the treatment for patients with multiple myeloma. The aim of this study was to assess indications for RT as well as its effectiveness in MM patients. Patients and methods: 67 patients were retrospectively analyzed with MMs who was admitted to multi-centric Institutes of Cancer during 5 years period. According to the staging system of Durie & Salmon 50 patients were classified as stage III. Nearly seventy present of patients (47/67) were treated with radiotherapy of at least one and up to 6 bony lesions at different times. Evaluation for the effect of local radiotherapy on pain relief and bone re-calcification was performed. Complete information on dose, fractionation and volume of radiotherapy was available from 35 patients treated in 56 target volumes for pain relief, and from 32 patients treated in 48 target volumes for recalcification. Total radiation doses varied between 8 Gy to 50 Gy (median dose 25 Gy in 2.5 Gy fractions, 5 times a week). Results: Radiotherapy resulted in complete local pain relief in 20(29.9%) and partial local pain relief in 36(53.7%) of the patients. The higher total radiation doses and higher age at the time of radiotherapy were significantly associated with a higher likelihood of pain relief, whereas no significant association was detected for concurrent systemic treatment, type and stage of myeloma and location of bone lesions. Re-calcification was observed in 47.9% of irradiated bone lesions. The higher radiation doses were significantly associated with an increased likelihood of re-calcification. Side effects of radiotherapy were generally mild. Conclusions: Despite the introduction of novel effective agents in the treatment of MM, RT remains a major therapeutic component for the management in 70% of patients. It continues to play a prominent role in the palliative treatment and it effectively provides pain control. However, the therapeutic measures appear to develop a better analgesic effect in elderly. Higher total biological radiation doses were associated with better pain relief and re-calcification in MM patients. Keywords: Multiple myeloma, Radiation therapy, Analgesic effect, Re-calcification, Side effects.
        Speaker: AYA ABAZA (Assistant Prof. of Safety and Prevention of Oncology at ENRRA)
    • Tuesday afternoon - Poster Presentations - Screen2
      Convener: Mr Oleg Belyakov (IAEA)
      • 58
        Measurement of testicular dose during the treatment of Ewing Sarcoma patient underwent External Beam Radiotherapy
        Purpose The present investigation aimed to measure testicular dose during the treatment of Ewing Sarcoma patient underwent external beam radiotherapy. Materials and methods A right sided pelvis Ewing Sarcoma patient aged 17 years with pubertal status was chosen for the study. The patient was planned to treat with external beam radiotherapy with radiation dose prescription of a total of 60 Gy/30#. The treatment plan of patient was planned on TiGRT treatment planning system (LinaTech). The patient was treated with 3DCRT on Siemens Oncor Expression machine. The thermoluminesense dosimeter system used in the study is a commercial TL reader system with CaSO4: Dy discs, manufactured by Nucleonix, India. Thermoluminesence dosimeters were used to measure the testicular dose during the external beam radiotherapy treatment. Results The TPS calculated testicular volume of right and left testicle was found to be 20.01 and 12.20 cc respectively. The TPS calculated doses for right and left testicle were found to be 1.40 cGy and 0.80 cGy respectively. The measurements were made for right and left testicle dose and observed doses were found to be 1.31±0.03 cGy and 1.03±0.12 cGy respectively. The cumulative dose to testes in whole treatment was estimated to 35.03 cGy. The percentage deviation between TPS calculated dose and TLD measured dose were observed 7% and 20% for right and left testes respectively. Conclusion TLD has been proven to be a promising dosimeter for in vivo dosimetry. The cumulative dose to testes in whole EBRT treatment was found lesser than the ICRP recommended threshold absorbed dose for occurrence of deterministic effect of radiation. Our results of dose to right gonad showed that the measurement of dose at the surface of testicular is sufficient to evaluate the dose to testicle during radiotherapy. However, TLD calculated dose for left gonad indicating the non reliability of TPS calculated dose for distant OARs from the radiation field.
        Speaker: Gourav Kumar Jain (Department of Radiological Physics, SMS Medical College & Hospital, Jaipur)
      • 59
        Early results and toxicity profile of Glioblastoma multiforme patients treated with hypofractionated Radiotherapy along with concurrent Temozolomide.
        Introduction: Glioblastoma multiforme (GBM) is one of the most aggressive and most common glial tumors. Maximal safe surgical resection followed by 6 weeks of adjuvant partial brain radiation (RT) with concurrent and adjuvant temozolomide (TMZ) is the standard of care. The present study assessed the acute toxicity and tolerance of a hypofractionated schedule of concurrent RT with Temozolomide in patients with GBM. Materials and Methods: From September 2012 to August 2016, 20 GBM patients were treated using various hypofractionation schedules, along with concurrent oral Temozolomide at a dose of 75mg/m2. Clinical information regarding patient demographics, tumor characteristics and treatment outcomes was assembled. Acute toxicity during radiation, reflected by unplanned discontinuation of RT, reduction in RT dose or treatment breaks due to haematological toxicity were assessed. Results: The median age of 20 evaluated patients was 48 years (range 22-68 years). The median Karnofsky Performance Status (KPS) was 80. The schedules used were 55Gy in 25 fractions (n=10), 50Gy in 20 fractions (n=5), 56.25Gy in 25 fractions (n=3), 51.75Gy in 23 fractions(n=1) and 52.8Gy in 24 fractions(n=1). Seventeen patients (85%) were treated with Volumetric Modulated Arc Therapy (VMAT), while three (15%) were treated using Intensity Modulated Arc Therapy (IMRT). Mean PTV volume (cc) was 270cc (range 77.7cc- 438.8cc). All patients completed the planned treatment course without any treatment interruption. Total treatment duration for 6 patients (30%) was ≤ 28 days and 29-36 days for the remaining 14 patients (70%). Fourteen patients (70%) were seen to have grade I CNS toxicity, while 3 patients (15%) experienced grade II CNS toxicity. Grade II alopecia was seen in 11 patients (55%) and all patients (100%) had Grade I skin toxicity at RT conclusion. No event of Grade II or higher haematological toxicity was seen in any patient. Conclusion: This retrospective study suggests that hypofractionated RT along with concurrent Temozolomide is safe and well tolerated. Such schedules can be used to decrease overall treatment times, logistically benefitting the patient and healthcare resources.
        Speaker: Nilaxi Khataniar (Fortis Memorial Research institute)
      • 60
        Biomarker predictors of radiotherapy response in head and neck tumors
        Biomarker Predictors of Radiotherapy Response in Head and Neck Tumor Misleidy Nápoles Morales, Xiomara Escobar, Rodolfo Alfonso Laguardia, Adianis Perez Calvo, Fanny López Reina National Institute of Oncology and Radiobiology Havana, Cuba. Email: Biomarker is defined as a molecule, a substance or process that is altered qualitatively or quantitatively as a result of a precancerous condition or cancer, detectable by a laboratory test in blood, body fluids or tissues. Biomarkers are useful in the diagnoses process, histological identification and therefore may contribute to the correct staging and further patient management. In head and neck tumors many biomarkers have been utilized as predictors of radiotherapy response. In a study conducted at the Oncology Institute of Havana from March 2014 to June 2016, a set of biomarkers (EGFR, Ki67,Bcl2 and P16) have been studied in a group of patients that received radiotherapy for head and neck cancer. The main goal was to recognize the relation between tumor response and expression of biomarkers. It have been reported that a positive EGFR, Ki67 and Bcl2 are associated with tumor progression, poor survival and more aggressive tumor. At the moment of this report, a total of fifty (50) Head and Neck (mesopharynx) patients that needed Radiotherapy have been included in this study upon informed consent. The abovementioned biomarkers were evaluated for all cases. The tumor biopsy was acquired and analyzed by the inmunohistochemical Lab of the Institute and the results were available before the radiation treatment started. All the patients were treated with 6 MV photons IMRT, based in the use of few static segments of fairly large areas, no less than 3x3 cm, and a reasonable dose per segment (> 3 MU). In the treatment planning system the weight of the segments is found using Cimmino’s algorithm. The irradiation beams setup was chosen with 9 co-planar equally spaced beams distributed around the patient. All patients were immobilized with the 5 points standard mask for head and neck used regularly at the department. The current status of the 50 patients is presented in Figure 1. Most of patients (72%), had a complete response to radiotherapy treatment, among them 41.6% expressed P16. The group of patients with the combination of: P16+, EGFR- , Ki67>20 and bcl2- shown a better response to radiotherapy than the patients with P16-, EGFR- Ki67>20 y bcl2+ combination. from this second combination 36% of patients had partial response (see Table 1) Given that all the histologies were classified as squamous carcinoma, it is surprising, however that the EGFR was positive only in the 6% of the cases. The use of predictor biomarkers in radiotherapy is an essential tool in the prognosis of the patient response to the treatment and the probability of tumor control. In low resources clinics, the identification of the higher impact biomarkers may contribute to optimize the procurement process.
        Speaker: Misleidy Nápoles Morales (INOR)
      • 61
        Treatment options in resource sparing setting for post-prostatectomy salvage radiotherapy: biochemical nadir and toxicity results from a non-randomized observational study
        Background: Limited information is available for hypofractionated radiotherapy after prostatectomy. We aimed to compare hypofractionated and conventionally fractionated radiotherapy regimens in salvage setting for biochemically recurrent prostate cancer after previous prostatectomy and record acute and late toxicity results. Methods: A retrospective analysis was performed in a total of 112 patients with proven PSA recurrence treated with radiotherapy to the prostate bed. Patients were non-randomly, in an alternating fashion, subjected to either 52.5 Gy in 20 fractions of 2.625 Gy over 4 weeks (N=60, hypofractionated group) or 66 Gy in 33 fractions of 2 Gy over 6.5 weeks (N=52, conventionally fractionated group). There was no statistically significant difference in pathologic T-stage and Gleason score distribution between the groups. In the conventionally fractionated group there were more patients with positive margins (p=0.01), more prevalent concomitant hormonal therapy (51.9% vs 62.2%, p=0.001), but less long-term hormonal therapy (20% vs 84%, p<0.001), compared to the hypofractionated arm. Median follow-up was 22 months (range 6-38 months). Treatment failure was defined as biochemical PSA nadir + 0.2. Failure rates between the groups were compared using Cox proportional hazards model. Acute genitourinary and gastrointestinal toxic effects were scored according to RTOG scoring scale from case report forms and patients' self-assessment questionnaires, at baseline, twice during radiotherapy, 3 months and 12 months after completion of radiotherapy. Results: At this early point, 15 patients (25%), and 7 patients (13%) experienced biochemical treatment failure in the hypofractionated group and conventionally fractionated group, respectively (HR 3.3, 95%CI (1.1-6.1). Due to the different fractionation regimes the dose volume histograms (DVH) have been analyzed in both arms. In the hypofractionated arm the following objectives were followed: bladder V40<80%, V48<50%; rectum V24<80%, V32<70%, V40<60%, V48<50%, V52.5<30%, and in the conventionally fractionated group: bladder V65<50%; rectum V50<50%, V60<35%, V65<25%. There were no difference in acute toxicity outcomes and no correlation between results of the DVH analysis and recorded side effects in both groups. More late grade 2 gastrointestinal and genitourinary side-effects were observed in the conventionally fractionated arm. No grade 3 toxicities were observed. Conclusion: A higher rate of biochemical failures was observed in the hypofractionated regimen compared to the conventionally fractionated regimen (non-significant; p=0.1), in salvage radiotherapy of biochemical failure following prostatectomy, despite a higher proportion of patients with positive margins in the latter group. Baseline heterogeneity between the groups and short follow-up preclude any causal conclusions of differential efficacy between these two schedules. Both radiotherapy regimes had similar grade 2 acute and late genitourinary and gastrointestinal toxicities. We plan to conduct a randomized phase II trial to prospectively compare these two regimens controlling for possible confounders.
        Speaker: Fröbe Ana (Department of Oncology and Nuclear Medicine University Hospital Center Sestre Milosrdnice University of Zagreb Medical School, Zagreb, Croatia)
      • 62
        Features of 18-FDG PET/CT application for recurrence detection, radiation therapy planning and its effectiveness monitoring in patients with tumors of the anorectal localization
        Background. Experience of 18f-FDG PET/CT clinical application confirms the usefulness of this imaging in oncology, namely: for the differential diagnosis, staging before surgery or radiation therapy, restaging after treatment. Also 18-FDG PET/CT showed high sensitivity for the efficacy monitoring of chemotherapy and radiotherapy. The numerous studies on the use of 18-of FDG PET/CT images for further dynamic control and radiotherapy planning proved higher results’ accuracy of systemic and loco-regional staging compared with conventional CT and MRI techniques. It was found that the macroscopic tumor volume determined by PET/CT is statistically significantly larger in the CT MPO with mean difference of 25%. Materials and methods. Between 11/2011 and 01/2016 the 18 FDG PET/CT was performed in 277 patients with colorectal cancer. Of them men were 154, women - 123; patients age was from 24 to 82 years. In overall 388 examinations were performed in 277 patients, including 94 without contrast and 294 with contrast. Average activity per injection was 373.98 MBq; in men - 402.75 MBq, in women - 332.62 MBq. We used Cyclotron Siemens Eclipse RDS for obtaining radiopharmaceuticals 18-FDG; and PET/CT Scanner Siemens Biograph 64. Results. Functional 18-FDG PET/CT images were used during planning of radiotherapy for rectum and anal canal carcinomas (Fig. 1). It is found that the PET/CT by sensitivity and specificity is more informative compared with conventional structural imaging techniques. Mean sensitivity and specificity of 18-FDG PET/CT for the main focus were 83% and 91%, respectively, while the corresponding indices for the basic CT method were respectively 64% and 74%. The sensitivity of lymph node involvement evaluation using CT method was 65% and PET/CT - 53%. It should also be taken into account the risks of false-negative results of PET/CT for lesions in the lungs less than 1.0 cm, small lesions in the upper sections of liver, located predominantly subcapsularly, and in histological tumor type - mucinous adenocarcinoma. It was found that applying PET/CT for staging caused changes of the treatment tactics in 55.4% of patients, of them in 15 – due to higher disease stage, and in 5 - scheduled surgery was not performed. Fig. 1. Planning of radiotherapy for rectum and anal canal carcinomas. Conclusions. 1. It was found that the 18 FDG PET/CT method possesses significant advantages concerning the disease recurrence detection and restaging in the cases when CT and MRI data are inconclusive. 2. It was proved that by sensitivity and specificity the PET/CT method is more informative for planning radiotherapy compared with conventional structural imaging techniques.
        Speaker: Oksana Solodyannikova (National institute of cancer)
    • Tuesday afternoon - Poster Presentations - Screen3
      Convener: Mr Oleg Belyakov (IAEA)
      • 63
        Comparison of points and volumetric doses using CT and MR images for 3D planning brachytherapy: A Brazilian experience
        Introduction Uterine cervix cancer, one of the most common tumors in the female population worldwide, is where brachytherapy plays a major role for local control and survival of these patients. Due the high dose-gradient of brachytherapy, it is possible to achieve the major challenge in radiation therapy to treat lesions with a high effective dose, while minimizing the dose in adjacent normal tissue or organs at risk (OAR). Image-guided (IGBT) or 3D gynaecological brachytherapy, that uses plans based on computed tomography or magnetic resonance has the potential to improve local control and survival in these patients, since it is possible evaluate the dose volume and then optimize the cost-benefit ratio between dose at tumor and organs at risk. Materials and Methods Alternated magnetic resonance images (MRI)and computed tomographies (CT)were performed for 12 patients that were treated for cervix cancer with 2D planning brachytherapy from April to September of 2010 using ring and tandemCT/MRI compatible applicator Nucletron®. Totally, 23 CT and 22 MR acquisitions were made after the insertion and fixation of the applicator in a specific support. The patients were then immobilized with the applicators in place in a vac-fix. For treatment, bladder was fulfilled with 50 cm3 of saline solution and a urinary catheter with a balloon with 5 cm3 of saline solution and 2 cm3 of contrast solution. 3D plans were performed on TPS OncentraMasterPlanNucletron®, using TC and MR images and applicatorsreconstruction were based on applicators library and prescription dose was 7 Gy at point A. However, this system was not commissioned at the beginning of this work, in such a way that all patients were treated with 2D planning performed on TPS Plato Nucletron®. The 2D evaluation points, ICRU points (ICRU 38, 1999), bladder (ICRUBladder) and rectum (ICRURectum), and sigmoid point (Sig) (Guimarães, et al, 2009) were added in 3D images in order to compare to a dose volume in each organ at risk (OAR). The volumetric comparison was made for 0.1 cm3 (D0.1cc) and 2 cm3 (D2cc) (Pötter, et al, 2006). Results The data analysis showed that CT and MRI based plans were statistically equal when comparing dose delivered to OAR´s, so the comparison was made using all data. Table 1 presents the results of the comparison of points and volumes doses. Table 1: Comparison of points and volumetric doses for OAR´s in CT and MRI based plans. The dose delivered to points in 2D plans was different from the volumetric dose in the OAR´s (p<0.05). The bladder point received dose lower than the volumetric dose for this specific organ, because when fulfilled, the bladder falls over the applicator in a high dose region while the vesical balloon stays in a low dose region. Even if the bladder point doesnot estimate the volumetric dose, it is still important to use this point when 2Dplans are performed in order to try to decrease the dose delivered to the bladder. The dose delivered to the rectum point was higher than the dose delivered to 0.1cc and lower than dose delivered to 2 cc, probably due to the fact that the rectum is an organ with less mobility. Therefore the rectum point is more representative of volume dose. The sigmoid is an organ with high mobility and the sigmoid dose point did not correspond to the volumetric dose for the organ. Conclusion 3D plans based on CT or MRIfor brachytherapy can help to spare OAR. In terms of OAR´s dose evaluation, the use of CT or MR showed to be equivalent. As consequence, both of them can be used to decrease volumetric dose at OAR´s. Since the points used in 2D plan did not show great correlation to volumetric dose, D0.1cc and D2cc respectively, the implementation of a 3D planning for brachytherapy seems to be very promising in order to improve gynecological brachytherapy treatment.
        Speaker: Camila Pessoa de Sales (Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo)
      • 64
        Age and insulin levels in breast cancer women and healthy women
        Introduction: Breast cancer is a common type of cancers among women; it is a heterogeneous disease lead to cause morbidity and mortality. Role of insulin in breast cancer etiology and prognosis has received attention. Insulin is an important hormone that controls blood sugar, fat and protein metabolism. Insulin release has reported to decrease with increasing age. However, age is considering the strongest risk factor for breast cancer after gender. Aim of this study to determine the age and serum insulin levels in breast cancer women and healthy women among Sudanese subjects. Methods: 130 newly diagnosed breast cancer women selected randomly in age range between 20-80 years, and 109 normal women in same age range as control. Population study classified to six age groups as (20-29),(30-39),(40-49),(50-59),(60-69)and ≥70 years . Excluding criteria includes diabetes, hypertension, heart diseases, thyroid diseases and fertility disorders. Information from questionnaire for patients and control group include dietary habits and physical activity. Insulin level measured by using radioimmunoassay, the normal range of insulin serum level is 4.0-16.8 mIU/L. Results: Insulin serum levels were normal in two age groups of (60-69) and ≥70 years for breast cancer patients. Elevation of insulin levels in breast cancer patients observed in age group of (20-29) years and decline seem to be constant in age groups of (30-39), (40-49) and (50- 59) years. All breast cancer patients were lake physical activity and low nutrients intake. Among control groups, the normal levels of insulin observed in two age groups of (20-29) and ≥70 years, insulin levels were normal in young women have physical activity and good nutrition. Women in old age ≥70 years have normal levels of insulin due to physiology of elderly such as menopause or β cell function. While, serum insulin levels elevated gradually in age groups of (30-39), (40-49) and (50- 59) years , and then decline in age group of (60-69) years , serum insulin levels were elevated with age increasing due to the nature of work, a lot of responsibilities and stress in these age stages. All these factors lead to low exercise activities and poor habits dietary. The mean levels of insulin among breast cancer women and healthy women explain in figure1. Figure 1: Insulin levels in different age groups among study population Conclusion: Elevation of serum insulin levels observed in both breast cancer women and healthy women,these results not support that high serum insulin level is directly associated to breast cancer; further studies need to clarify whether cases of high insulin levels enhance cell proliferation and associated to breast cancer etiology. Constant of insulin levels in age range between 30-59 years in newly diagnosis breast cancer that may link positively to hypoxia, and then after therapy the concentrations of insulin in blood circulation may increase significantly with acute hypoxia. This findings suggest that, future studies recommended to explain the association between hyperinsulinemia and hypoxia intermediated with nutrient agents like trace elements, especially those are affect insulin levels as chromium, zinc, copper and selenium, beside others minerals as iron. Pharmacology should be considered for hyperinsulinemia to improve outcome of radiotherapy for breast cancer patients, and to protect the women having high insulin levels from breast cancer development. Several factors may increase breast cancer risk by affecting insulin levels combined to lifestyle factors include lacking physical activity and poor nutrition. It is important to care with health in all ages of life.
        Speaker: Alkhansa Mahmoud (Sudan Atomic Energy Commission)
      • 65
        Breast cancer recurrence monitoring a corroding to tumour subtypes: Role of serum tumour markers CA 15-3 and CEA using radioimmunoassay
        Introduction: Breast cancer is one of the most common types of cancer worldwide, with increasing incidence and mortality. Breast cancer patients concerned to avoid of breast cancer recurrence. Tumor markers are substances found in the body and produced by cancer cells. Tumor markers and imaging tests such as Computed Tomography (CT) , Positron emission tomography (PET) and bone scans have been used for monitoring breast cancer recurrence after therapy, these imaging have risk and cost, while tumor markers is easy and cost-effective. The aim of this study to detect the early breast cancer recurrence using tumor markers Cancer Antigen15-3 (CA 15-3) and Carcinoembryonic Antigen (CEA) during therapy Methods: Forty six of breast cancer women in age ranged between 17 and 65 years, were selected randomly to participate in this study, 23 of them were on treatment for 3 months (Chemotherapy doses) and 23 were complete the first line of therapy about 6 months (Ionizing radiation and chemotherapy doses /or complete chemotherapy regime). Clinical data information including age at diagnosis, stage , estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status. Radioimmunoassay used for measuring the concentration of serum CA 15-3 and CEA in breast cancer patients, the reference range of serum CA 15-3 is < 30 U/Ml and CEA is < 3.0 ng/ml. Patients were followed up by observed them in the clinic for 24 months. Results The mean and standard deviation of CA 15-3 of breast cancer patients on treatment were (18.0 ± 11.3), while in the patients after treatment were (16.0 ± 9.0). The mean and standard deviation of CEA for the patients on treatment and after treatment were (4.3 ±5.0) and (4.5 ±5.5) respectively. Twenty-two patients were luminal B and Twenty-four patients were triple negative subtypes. Twenty of the patients suffered the early recurrence in a period less than 24 months. High levels of CA 15-3 seen only in five patients in stage3 and luminal B subtype (ER+, PR+/ PR-, HER2+). While elevation of CEA levels observed in, tow patients were luminal B and twelve patients were tribal negative breast cancer subtypes. However, three patients suffered distance recurrence in bone and lung, were have normal serum levels of tumor markers CA15-3 and CEA during treatment, and tow patients of them died during follow-up period . Figure (1) explains the mean levels of CA15-3 and CEA among breast cancer subtypes in this study. Figure1: Mean levels of Tumour Markers CA15-3 and CEA among breast cancer subypes Conclusion CA 15-3 may be useful for monitoring breast cancer recurrence at initial recurrence diagnosis in luminal B subtype. Elevated CEA serum levels during treatment were associated with early recurrence in luminal B and tribal negative breast cancer subtypes. Tumor markers CA 15-3 and CEA cannot monitor breast cancer recurrence in some cases such as distance recurrence in bone or lung.
        Speaker: Alkhansa Mahmoud (Sudan Atomic Energy Commission)
      • 66
        Hypofractionated conformal radiotherapy and chemotheapy in treatment of malignant gliomas
        Background: patients with high-grade gliomas are generally elderly patients with poor performance status and associated morbidities. We compared results of hypofractionated radiotherapy with standard fractionated radiotherapy. Hypofractionated radiotherapy with or without chemotherapy could be an appropriate treatment option for these patients with poor life expectancy. Patients and Methods: Sixty -five patients with malignant gliomas, treated in our Institute between 2005 and 2010, have been identified for this study. Median age was 69 years (between 65 and 81 years). Karnofsky Index (KI) was more than 70% in 38 patients (58.46%) and equal or less than 70% in 27 patients (41.54%), better for patients under 74 years old. Most frequent associated morbidities have been high blood pressure, cardiovascular diseases and diabetes, 54 patients (83,1%). Depending on histological types there have been 44 patients with glioblastoma multiforme (67.69%) and 7 patients with anaplastic astrocytomas (10.77%) and 14 patients (21.46%) with less frequent histological types. Complete resection of tumor was performed in 50 patients (76.9%), partial resection in 13 patients (20%) and biopsy in 2 patients (3.1%). Postoperative treatment was performed as radiotherapy and chemotherapy in 41 patients (63.08%) and radiotherapy only in 24 patients (36.92%). Radiotherapy (RT) was performed as standard fractionated conformal radiotherapy (CRT) with median total dose of 58,5 Gy (minimum 40 Gy, maximum 60 Gy) with 2Gy/fr in 22 patients and hypofractionated CRT with median total dose 30.0 Gy, (minimum 16 Gy, maximum 45 Gy) with 2.66 to 4 Gy/fr, in 43 patients. Chemotherapy with temozolomide was performed in 41 patients (64.08%): concomitant and adjuvant in 22 patients (33.85%), concomitant only with RT in 15 patients (23.08%) and adjuvant to RT in 4 patients (6.15%). The following parameters have been observed: 1) KI, measured at the beginning and the end of treatment; 2) toxicity of RT, appreciated using RTOG scale and 3) toxicity of chemotherapy (hematological, digestive, renal and other) during concomitant and adjuvant phase, appreciated after CTCAE version 3.0. The end points of treatment have been overall survival and toxicities of treatment. Results: The median follow-up was 32.6 months with 55 deaths and 10 patients alive. Overall survival (OS) at 36 months was 13% (CI: 7%-25%) for the entire group of patients. The OS depending on treatment type was: 20% for patients treated with RT and concomitant chemotherapy; 16% for those treated with radiotherapy only and 7% at 36 months for concomitant and adjuvant chemotherapy, p=0.35 (NS). The shortest survival was seen in patients treated with adjuvant chemotherapy to RT, less than 1 year. The OS versus type of RT was 20% for patients treated with standard fractionated RT and 9% for those with hypofractionated RT, differences not statistically significant (p=0.02). Toxicity of radiotherapy (RTOG scale) was 0 and 1 in 41 patients (63.07%) and 2 and 3 in 24 patients (36.92%) with no statistically significant differences between the two types of fractionation: p=0.25. OS depending on toxicities was between 16% and 11% at 36 months, p=0.10. There have been 7 patients with grade 3 and 4 toxicities in chemotherapy treated group (41 patients): 4 in concomitant phase and 3 in adjuvant phase. Conclusions: Hypofractionated radiotherapy was well tolerated with or without chemotherapy with acceptable toxicities and could be a good treatment option for elderly patients with high-grade gliomas. Important decisions factors for fractionation type and total dose administered are performance status, associated diseases and generally life expectancy of patients.
        Speaker: Dana Michaela Cernea (Oncology Institute "Prof. Dr. ION CHIRICUTA")
      • 67
        Neutron-gamma mixed field dosimetry on a child phantom under therapeutic proton irradiation using TL dosimeters
        Introduction: During proton therapy energetic proton beams deliver a highly conformal dose to the primary tumor mass; thereby, reducing unwanted radiation exposure to the neighboring healthy tissue. These unique characteristics provide significant therapeutic advantages in comparison to the well-established photon-therapy. However, a significant number of secondary particles, predominantly fast neutrons and gamma-rays, are produced by the interaction of the main proton beam with the beam shaping and modifying devices located inside the beam delivery nozzle as well as from the irradiated volume itself. This results in an unwanted increase in radiation exposure of sensitive organs located outside of the treated volume, thereby increasing the risk of second cancer incidence. Children are more vulnerable to 2nd cancer risk than adults due to longer life expectancy, shorter distance between organ at risk and primary radiation source and higher cell differentiation rate of organ tissues of interest. This paper presents the application of twin-TLD (TLD-500 and TLD-700) dosimetry technique developed at WPE for in-situ estimation of the out-of-field neutron and gamma dose equivalents. The TLD pairs were placed on selected organ locations of an anthropomorphic phantom while a simulated 125 cm3 skull based tumor was irradiated with protons in uniform scanning (US) mode. A prescribed dose of 2 Gy in a single fraction was delivered in three fields. The results and dosimetry protocol from this benchmark experiment could be used to estimate the neutron and gamma dose equivalents during proton irradiation of a child phantom, emulating a pediatric cancer patient. Methods: Commonly used TLD-700 (7LiF:Ti,Mg) dosimeters are highly sensitive to gamma rays. On the other hand, the high-temperature region (HTP) of the TL-glow curve of TLD-700 is also responsive to fast neutrons, however, contaminated with gamma background. Hence, a method to eliminate the gamma background of the HTP region using primarily gamma sensitive TLD-500 (Al2O3:C) dosimeters has been developed. A polystyrene plate phantom (20 cm x 20 cm x 30 cm) was bombarded with 170 MeV protons to produce high-energy neutrons of similar energy distribution like neutrons generated during proton treatment of tumors. A Wide Energy Neutron Detection Instrument WENDI 2 (capable for dose equivalent estimation of neutrons from thermal to 5 GeV energies) was used to cross calibrate the TLD chips. The TLD chips were evaluated using a hospital based TLD reader and annealed thereafter. The annealed pairs of TLD-500 and TLD-700 chips were attached to the location of Left/Right Eye, Thyroid, Left/Right Lungs, Stomach and Gonad of the child phantom. A simulated skull-base tumor (125 cm^3) was irradiated with a single fraction 2 Gy proton dose. Results: The gamma background correction factor (kG), gamma (fG) and neutron (fN) dose equivalent conversion factors are given as: kG = TLD700AHTP /TLD500AMP (1) fG (mSv/nC) = calibHG/TLD700AMP (2) fN (mSv/nC) = calibHN/(TLD700AHTP-kG xTLD500AMP) (3) Where, TLD700AHTP and TLD500AMP are the high-temperature peak of TLD-700 and main peak of TLD-500 chips respectively. Furthermore, calibHG and calibHN are the calibration gamma and neutron doses delivered to TLD-500 and TLD-700 chips respectively. By substituting the numerical values in equations 1, 2 and 3 the gamma (FG) and neutron (fN) dose equivalent calibration factors were evaluated to be 1.68 x 10^-5 and 1.22 x 10^-4 mSv/nC respectively. The organ specific out-of-field gamma (OrganHG/DP) and neutron (OrganHN/DP) dose equivalent per delivered proton dose (DP) were calculated as follows: OrganHG/DP (mSv/Gy) = fG x TLD700AMP (4) OrganHN/DP (mSv/Gy) = fN x (TLD700AHTP-kGxTLD500AMP) (5) Using the TLD readings the organ specific gamma and neutron dose equivalents were estimated explicitly and the results are depicted in Figure 1. Conclusion: During proton therapy predominantly high-energy neutrons with energies up to excess of 100 MeV prevail outside the treatment volume. These high-energy neutrons essentially contribute to risk of second cancer at out-of-field organs. The risk is higher in child patients due their smaller physical size and longer life expectancy. The twin-TLD method for explicit estimation of out of field gamma and neutron dose equivalents requires a common hospital/clinic based TLD reader and an annealing oven. Technicians can conveniently sterilize the tiny dosimeter holders sealed in pouches prior to routine clinical applications. The technique is ideally suited for dosimetry procedures where high spatial resolution (i.e. small detector size) and direction-independence of detector response are required, in particular for pediatric proton therapy cases. At West German Proton Therapy Center Essen (WPE) the results of these benchmark measurements have already been implemented to study the second cancer risk of pediatric patients of various cancer indications, ages and genders.
        Speaker: Bhaskar Mukherjee
    • Tuesday afternoon - Poster Presentations - Screen4
      Convener: Mr Oleg Belyakov (IAEA)
      • 68
        Survival and prognostic factors in non metastatic breast cancer
        Issue: Breast cancer is the most common cancer of women in Tunisia and in the world. It represents a serious public health problem. Several studies have identified its standardized incidence, including two medical doctoral theses supervised by the radiotherapy department of the Salah Azaiz Institute of Tunis. Data about the prognosis and the evolutivity of this disease are not current. The study of survival and prognostic factors is essential to improve the prognosis of this disease. Purpose: The aim of this study was to describe the clinical and therapeutic features of non-metastatic breast cancer, to calculate the overall survival at 5 years and 10 years, to investigate the prognostic factors of overall survival and disease-free survival, and to compare our results to those of a similar Tunisian study performed in 1994. Materials and methods: This is a retrospective study of 474 patients with non-metastatic breast cancer diagnosed between January 1, 2004 and December 31, 2004, treated and followed at the Salah Azaiz Institute. Clinical, histological, therapeutic data have been collected. The patients have been divided into Groups according to T stage (Group 1: T0, T1, T2 and T3, Group 2: T4a, and T4b T4c, Group 3: T4d tumors) in accordance to the grouping method used in 1994. Our series of patients were also classified into Stages according to the classification of the AJCC 2010. Overall survival factors were studied for groups 1 and 2 and the disease-free survival factors were studied for the group 1, in order to compare our results with those of 1994. Similarly, overall survival factors were studied in the different stages in order to compare our results to the literature data. Univariate statistical analysis has been done by the Kaplan-Meier method and multivariate analysis by Cox regression method. Results: Our study concerned 474 patients, including 12 (2.5%) men. The mean age was 51.8 years. The average clinical size was 39 mm. Stage II was the most common (55.9% of cases). Stage III accounted for 26.8% of the patients and inflammatory tumors 4.4% of the population. The median follow-up was 93 months. Distant failure was the most frequent way of relapse since 28.9% of patients developed metastasis during 10 years of follow up. Overall survival was 74.4% at 5 years and 54% at 10 years for all stages with an average survival of 95.8 months. There was a statistically significant difference between the different stages in terms of overall survival and disease-free survival (p <0.05). Independent factors of overall survival in stage II were tumor size, hormonal status, surgical limits and metastatic relapse. In stage III, we have retained the hormonal status and metastatic relapse as independent factors for overall survival. After univariate analysis, younger age and high grade SBR were the significant factors of local recurrence after conservative surgery (p ≤ 0.05). Yet, extracapsular extension in involved lymph nodes, was the only significant factor for local recurrence after mastectomy (p ≤ 0.05). ). Young age, tumor size, an in situ component, extracapsular extension, hormonal status and local recurrence were significant factors for lymph node recurrence in the group of localized tumors (p ≤ 0.05). Prognostic factors for metastatic recurrence-free survival were searched in stages I and II. In univariate analysis, we have retained tumor size, lymph node status, number of involved lymph nodes, hormonal status, local recurrence and regional recurrence as significant factors for distant relapse in stage II. In stage III, age, time between surgery and radiotherapy and nodal status have emerged as significant factors for metastasis free survival. A comparative study between our results and those of the 1994 cohort has found a gain of 20% in terms of overall survival as the overall survival rate at 5 years was 53.2% in 1994. The difference in survival between two periods was statistically significant and was also observed at the specific survival. This survival benefit would be due to a decrease in tumor size at diagnosis (52 mm in 1994 vs 39 mm en 2004) and consequently a decrease in the rate of stage III tumors and especially the rate of inflammatory breast cancer (10% in 1994 vs 4 4% in 2004). It would also be due to a decrease in the rate of lymph node invasion (76.8% in 1994 vs. 59% in 2004) and to a greater use of conservative surgery, chemotherapy, and endocrine therapy for the series of 2004 compared to the year1994. Conclusion: The prognosis of our patients was particularly related to the stage of the disease and the quality of care reflecting some shortcomings of the health system. The improvement of prognosis between 1994 and 2004 was encouraging and impels to multiply efforts to establish early diagnosis and better health care.
        Speaker: Semia ZARRAA
      • 69
        Comparative study of two techniques for spinalcord irradiation with 3D conformational planning
        **Comparative Study of two techniques for Spinalcord irradiation with 3D conformational planning** **Introduction of the study** Craniospinal irradiation (CSI) remains technically challenging because clinical target volume coverage is not a simple matter, that includes whole brain and whole length of the spinal axis and covering meninges.  The traditional position of delivering CSI has been with the patient in the prone position, using lateral opposed fields covering the whole brain and upper cervical spine matched to posterior direct fields covering the caudal extent of the spine.  Conventional treatment of adult spine usually exceeds the maximum field size available in standard linear accelerators and requires two matched spinal fields, typically accomplished with a skin gap between them. However, the gap or overlap between the fields can yield unacceptable dose heterogeneity and potentially be responsible for compromising the optimum tumor control. At our centre, we compare the conventional CSI technique using gaps and a modified 4-field technique, which employs column fields with table rotation angle and gantry angle in order to eliminate the divergence between them and allow a closer matching. **Methodology** Our CSI patients were planned using computed tomography (CT) simulation, with the patient in the prone position lying on a Styrofoam plate in order to maintain the head position in the same level of whole spine, minimizing the curvature of the cervical spine and eliminating potential skin folds. The arms are placed down to the body side and the head is supported on a standard headrest besides thermoplastic mask immobilization. CSI treatment planning is performed using Eclipse treatment planning system (Varian, Palo Alto, CA). Two separate treatment plans were generated for each patient, with the aim of comparing the traditional technique and the 4-field modified technique (see Fig.1). For both techniques, the 2 opposed cranium field isocenter was positioned toward the patient feet as possible, i.e. using asymmetric collimator jaws with cranial superior border in the maximum size available. The inferior border was set limited by shoulder, including in the cranium fields as much as possible of the cervical spine and avoiding irradiating the mandible, oral cavity and larynx by the exit of spinal field. Efforts were made to spare the lenses using gantry rotation. We also employed couch rotation to eliminate the divergence in the direction of column fields. In the traditional technique (Fig. 1(a)), cranium field collimator angle is set zero, once the upper part of column is treated by a half-beam blocked field with isocenter localized in the cranium-spinal junction. Treatment of bottom part of the column is delivered by a direct field and the amount of overlap caused by the divergence of the upper and lower column fields is eliminated by the imposition of a skin gap so that both fields match in treatment depth. The cranial fields in the modified technique (Fig. 1(b)), in turn, employs also angle collimator in addition to the gantry and table angle. The purpose is to follow the direction of the superior upper column edge field, whose divergence is in the cephalic direction. In this technique, upper column field isocenter is located 20cm shifted longitudinally in relation to the edge of the cranial field, so that the blocked half of the half-beam field eliminates the divergence in the direction of bottom column field. Finally, the bottom column field is treated with 90º couch rotation, eliminating divergence of bottom field and providing a perfect match without gaps in whole column. **Results** We made qualitative dose distribution evaluation in the axial, coronal and sagittal planes for both techniques. For adult patients, whose extension column exceeds the maximum size available field on the accelerator, the dose distribution in the modified technique was qualitatively higher by the absence of underdose (before normalization depth) and overdose regions (after normalization depth) in the mediastinum of the patient. DVH evaluation also indicated a better and more homogeneous coverage of clinical target volume. Quantitative evaluation through indicators such as cold and hot spots, and homogeneity index (following the description of ICRU83) revealed that both techniques are comparable. **Conclusion** In contrast to traditional technique used in spinalcord irradiation, the modified technique previously described has the ability to eliminate the use of undesirable gaps between the fields, so that the whole clinical target can receive more homogeneous dose without compromising tumor control. The major difference between them is that the modified 4-field technique requires couch rotation to treat column fields, and it is simple to plan and easy to incorporate into the workload of radiotherapy department.
        Speakers: Milena Sereno (Hospital Heliopolis) , Valeria Ferreira (Hospital Heliopolis)
      • 70
        Prevention and treatment of acute radiation injuries of the head and neck region
        The main dose-limiting factor in radiation therapy (RT) is a toxic effect of ionizing radiation on human body. One of the pressing issues in radiation oncology is prevention and treatment of mucositis arising during radiotherapy. This issue still remains important in radiation oncology not only for developing countries. The influence of consequences of severe acute injuries was demonstrated by Sonis S.T. in 2004 by US data showing the 6-30% mortality rates of patients with radiation-induced mucositis. In addition, the development of severe mucositis is a major cause of forced deviations from planned volume and regime of treatment. The aim of this study is to investigate the frequency and severity of mucositis and dermatitis arising in the dynamics of radiotherapy of patients with the head and neck squamous cell carcinoma (HNSCC). Materials Work is based on results of treatment of 1423 patients with HNSCC, treated in Armenian National Oncology Center from 2000 to 2014. The analysis of incidence and degree of severity of acute radiation toxicity depending on applied treatment methods is performed. The radiotherapy was conducted on the basis of a two-dimensional planning to all patients. The curative course of conventional RT has been assigned to 796 patients, including 107 patients after tracheostomy. The total dose was 60-66 Gy. In addition, another 194 patients underwent synchronous chemoradiation therapy. Adjuvant RT course received 433 patients. Median age of patients was 60 years. The ratio of men to women was 8.5/1, and dramatically varied depending on tumor site and age of patients. Thus, the median age for nasopharyngeal tumors was 53 years, and the ratio m/f ═ 2.8/1, while in the laryngeal cancer, the rate of the median age increased to 62 years, and the rate of the ratio m/f to 37.5/1, respectively. Results The severity of mucositis and dermatitis was evaluated by RTOG toxicity scale. The toxic manifestation of radiation 0 - III degrees was detected in almost all patients. Only 13 (0.91%) of 1423 patients completed the course of RT without acute effects of radiation damage. The fourth degree of toxicity was not registered. Mucositis began to appear after 7 - 15 days after the start of RT. The data on the frequency and severity of mucositis registered is shown in Table 1 in dependence of type of treatment. The detection rate of mucositis of second and third degrees is considerably increasing in the cases of RT after surgery and when it is combined with chemotherapy. This fact can be explained by deterioration of local blood flow after surgery and the treatment of surgical wound by chemically active substances, also by toxic influence of chemotherapy agents to mucosal covers. Additive interaction of two toxic agents at their simultaneous appointment with RT leads to an increase in frequency of mucositis II-III degrees. The compelled breaks of treatment course, caused by acute mucositis, were registered in 313 patients, with duration 5-18 days. Also, treatment course was not finished in planned volume in 21 cases, because of dramatically decrease of performance status, including three cases with acute cerebral circulatory disorders and two cases due to the acute coronary insufficiency. To avoid the compelled interruption of RT, 183 patients administered conventional means with preventive purpose: mouth rinse by herbs broths and different anti-inflammatory medicines. Decoction of developed by us prescription of medicinal plants was used in 69 cases for prevention of radiation induced mucositis. All of these 69 patients completed the course of curative RT without forced interruption. Same recipe in form of inhalations, rinse was prescribed not only preventive but also for therapeutic purposes in already developed mucositis, however, in this case it turned out to be ineffective. Since 2009, we used a new recipe of herbs in 74 patients, which had a pronounced therapeutic effect in different grades of mucositis, shortening forced break of treatment up to 2 - 3 days. Conclusions 1. The degree of mucosal and skin damage doesn`t affect life expectancy, if the forced break doesn`t exceed 15 days. 2. It is recommended to all patients to start administration of the prophylactic complex for mucositis and dermatitis prior to RT, regardless of the condition of the mucosa of the upper parts of air-digestive tract. 3. The proposed collection of medicinal plants has proven effective not only for prevention of mucositis, but also can be recommended for treatment after their development during RT. 4. The use of the proposed methods of prevention and treatment of radiation dermatitis and mucositis allows to achieve the planned volume and doses of RT on the tolerable acute toxicity without the use of high technology (3D-CRT, IMRT). 5. Sharp deviation in the ratio of male/female and the median age is revealed, depending on tumor location.
        Speaker: Nerses Karamyan (Radiation Oncologist, National Centre of Oncology, Armenia)
      • 71
        Evaluation of BEBIG HDR+® dose optimization methods: A case study of HDR brachytherapy cervical plans
        **Introduction:** High dose rate brachytherapy (HDR) has taken an important place in the treatment of cervical cancer. Treatment planning system is required to calculate dwell time and position. Many methods are used to optimize those parameters such as manual method and automatic method. The aim of this work is to compare graphical (GRO) and inverse planning by simulated annealing (IPSA) optimization methods offered by BEBIG HDR+® for cervical plans considering dosimetry and planning time. **Methodology:** Ten retrospective cervical brachytherapy patients were chosen for this study. Manual GRO and IPSA plans were generated for each patient. Plans were compared using dose-volume histograms (DVH) and dose coverage metrics including; conformal index (COIN), and homogeneity index (HI). Approximate planning time was also recorded. **Results:** There was significant difference between GRO and IPSA in terms of mean COIN of 1.34 and 1.18 (p=0.04) and no significant difference in terms of mean HI of 0.32 and 0.44 (p=0.09) respectively. Mean GRO planning times were greater than 20 min while average IPSA planning times were less than 10 min. **Conclusion:** For the same dosimetrical plan, IPSA offers a reduced planning time compared to GRO.
        Speaker: Ismail ZERGOUG (Radiotherapy department-EHSO Emir Abdelkader Oran)
      • 72
        Evaluation of radiation doses to organs at risk and comparison the toxicity with application of modern techniques radiotherapy of treatment patients for prostate cancer
        **Keywords:** Hypofractionated radiotherapy, IMRT, prostate cancer, toxicity. Background: Cancer of the prostate is one of the most important medical problems facing the male population. Radiotherapy (RT) is one of the major methods of treatment for prostate cancer. **Purpose**. The aim of this study was to compare doses for the bladder and the rectum and to estimate manifestations of acute genitourinary toxicity (GU) and gastrointestinal toxicity (GI) with application three-dimensional conformal RT (3D-CRT) and intensity modulated RT (IMRT) with using the classic mode of fractionation and hypofractionation regime. **Material and Methods:** 102 patients with intermediate-risk prostate cancer were treated 5 days per week: using 3D-CRT 74 Gy in 37 fractions (n=33), using IMRT with classic mode 76 Gy in 38 fractions (n=32) and using IMRT with hypofractionation regime 67.5 Gy in 27 fractions (n=35). Compare the medium doses for the bladder and the rectum was performed using dose-volume histogram. Acute local toxicity was assessed with the scale RTOG/EORTC. Acute toxicity scores were recorded weekly during treatment and 3 months after radiotherapy. **Results:** Median dose for the bladder was: 3D-CRT 55.10±8,65 Gy, IMRT with using the classic mode of fractionation 44.84±9.10 Gy, with using hypofractionation regime 44.31±4.36 Gy . Median dose for the rectum was: 3D-CRT 52.39±6.88 Gy, IMRT with using the classic mode of fractionation 44.19±8.49 Gy, with using hypofractionation regime 42.29±8.83 Gy. GU toxicity grade 1 was 3D-CRT for 21 evaluated patients (65.6.9 %), IMRT with using the classic mode of fractionation – 18 (56.3 %), IMRT with using hypofractionation regime – 19 (51.4 %). Also grade 2 was 3D-CRT – 7 (21.9 %), IMRT with using the classic mode of fractionation – 6 (18.6 %), IMRT with using hypofractionation regime – 7 (20.0 %). And grade 3 was 3D-CRT – 2 (6.25 %). GI toxicity grade 1 was 3D-CRT for 22 (66.8 %) patiens, IMRT with using the classic mode of fractionation – 20 (62.5 %), IMRT with using hypofractionation regime – 20 (57.1 %)/ Also grade 2 was 3D-CRT – 8 (24.2 %), IMRT with using the classic mode of fractionation – 5 (15.6%), IMRT with using hypofractionation regime – 6 (17.1 %). And grade 3 was 3D-CRT – 3 (9.0 %). The median follow-up was 22•0 months (IQR 14•4–38•2). **Conclusions:** According to the survey, with 3D-CRT dose to organs of risk more than an average of 11.0 Gy to the bladder (U-test, p<0.05) and 9.0 Gy - to the rectum (U-test, p<0.05). Analysis dose to organs of risk proves that using IMRT with using hypofractionation regime the values of radiation dose comparable to IMRT with using the classic mode of fractionation. Only in the group 3D-CRT we observed acute toxicity grade 3.
        Speaker: Olena Safronova (Clinical Hospitale "Feofaniya")
    • Tuesday afternoon - Poster Presentations - Screen5
      Convener: Mr Oleg Belyakov (IAEA)
      • 73
        Impact on dose and volume on irradiated brain on recurrence and survival of patients with glioblastoma multiformae
        **Introduction:** Glioblastoma multiformae is the most common and the most aggressive brain tumor. Despite the major advantages in personalization and precision of the treatment, median survival of patients is approximately 12 to 16 months. Today standard of care for patients with glioblastoma is postoperative radiotherapy with temozolomide followed by adjuvant temozolomide. Radiation is corner stone of the treatment and with highest benefit of all modalities of the treatment. **Methods:** Dosimetric analysis of treatment plan data has been performed on 70 patients with glioblastoma, treated with postoperative radiochemotherapy with temozolomide, followed by adjuvant temozolomide. Patients were treated with 2 different treatment approaches, regarding definition of treatment volumes and prescription of radiation dose. First group of patients has been treated with one treatment volume receiving 60 Gy in 2 Gy daily fraction (31 patients) and second group of the patients has been treated with “cone down” technique, which encompass of two phases of treatment, first phase 46 Gy in 2 Gy fraction followed by “cone down” boost of 14 Gy in 2 Gy fraction (39 patients). Quantification of “V57Gy”, volume receiving 57 Gy and more and ratio between brain volume and “V57Gy” has been done. Average values of both parameters have been taken as a threshold value and patients have been split into 2 groups for each parameter (smaller and lager than threshold value). **Results:** Mean value for Volume “V57 Gy” was 593,39 cm3 (range 166,94 to 968,60 cm3), Mean value for brain volume has been measured as 1332,86 cm3 (range 1047,00 to 1671,90 cm3) and mean value for ratio of brain and “V57Gy” has been 2,46 (range 1,42 to 7,67). Time to progression and overall survival of patients has been analyzed using Kaplan-Meir methodology. There was no significant difference between two groups for both “V57Gy” and ratio between brain volume and “V57Gy”. **Conclusion:** Irradiated volume with dose more than 57Gy (“V57Gy) and ration between whole brain volume and “V57Gy” does not have any impact on recurrence and survival of patients with glioblastoma.
        Speaker: Igor Stojkovski (University Clinic of Radiotherapy and Oncology)
      • 74
        An audit of nasopharyngeal rapidArc radiotherapy planning against ICRU 83 target volume homogeneity and conformity guidelines: a single center study
        Introduction: The ICRU reports number 50 and 62 guidelines for dose homogeneity and dose conformity on the PTV to be confined within 95% to 107% of the prescribed dose is difficult to be maintained for IMRT plans, and it is almost impossible for VMAT. ICRU 83 recommends assessing the target volume homogeneity by evaluating the high- and low-dose regions using dose-volume quantities such as D2% and D98%. However, the report did not elaborate on specifics limits for these quantities. The variation of these quantities may vary depending on the disease site as the geometrical configuration of target volumes and organs at risks (OARs) varies, and IMRT technique due to its different capabilities in delivering and confirm the radiation dose. Nasopharyngeal cancer (NPC) is a rare malignancy in most parts of the world, however other populations with elevated rates include Southeast Asia, the natives of the Artic region, and the Arabs of North Africa and parts of the Middle East. In treatment planning of NPC patients with IMRT techniques, three different dose levels are usually delineated to cover the high-risk, intermediate, and low-risk disease regions. A concomitant boost radiotherapy is usually used to deliver 70 Gy to high-risk target volume (PTV70), 63 Gy to intermediate target volume (PTV63), and 56 Gy to low-risk target volume (PTV56) in a total of 35 fractions. Several publications proved the superiority of volumetric modulated arc therapy (VMAT) over other modern delivery techniques such as intensity modulated radiotherapy (IMRT), and Tomo therapy for NPC radiotherapy treatment. In these comparative studies, the judgment on the better technique was based on dose volume histogram (DVH) comparison with no correlation nor compliance with any international recommendation due to the lake of it. Methodology: In this study we accessed our clinical practice in treating NPC patients using RapidArc delivery technique. All NPC patients treated with RapidArc for the past three years were evaluated (n= 115). The dose volume histograms (DVH) for the three target volumes were exported and a number of target coverage dosimetric parameters were determined and analyzed using an in-house MATLAB code. All the plans were clinically accepted and all OARs doses were within the QUANTEC constrains. These dosimetric parameters included volume parameters such as volume receiving 107%, 95%, 100% of the prescribed dose and total volume size (V107%, V95%, V100%, and Vtotal respectively), and dose parameters such as dose to 2%, 98%, 50%, and 1 cc of the target volume (D2%, D98%, D50%, D100% and D1cc respectively), and dosimetric indexes such as conformity index (CI), homogeneity index (HI), and quality of coverage (Q). All dose and volume percentages were calculated according the prescribed dose and volume for each individual target volume. Results: The average target-volume sizes recorded (mean ± SD) were 243.5 ± 151.2, 284.6 ± 127.4, and 363.3 ± 170.5 cm3 for PTV70, PTV63, and PTV56 respectively. The average D2% as an indicator for high-dose region was 107.5 ± 1.7 % (range: 102.6 – 112.6) for PTV70 while it was 111.3 ± 2.6 %, and 110.7 ± 3.5 % for PTV63 and PTV56 respectively. Moreover, the average V107% were 10.6 ± 13.9, 29.3 ± 21.2, and 25.2 ± 22.5 % and the D1cc were 106.0 ± 8.4, 101.1 ± 6.5, and 110.3 ± 4.7 % for PTV70, PTV63, and PTV56 respectively. On the other hand, the average D98% as an indicator for low-dose region were 96.3 ± 3.9 %, 95.7 ± 3.8 %, and 96.4 ± 3.9% and the average V95% were 98.6 ± 2.3, 97.9 ± 2.5, and 95.7 ± 14.4 % for PTV70, PTV63, and PTV56 respectively. The volume coverage parameter V100% and the dose coverage parameter D100% were 89.5 ± 10 % and 89.8 ± 7.7 %, 89.5 ± 9.3 % and 79.5 ± 7.3 %, and 89.5 ± 18.2 % and 72.4 ± 8.7 % for PTV70, PTV63, and PTV56 respectively. The best HI and Q were recorded for the high-risk volume (0.11 ± 0.03 and 0.98 ± 0.05 respectively) compared to intermediate and low-risk volumes (0.14 ± 0.05 & 0.14 ± 0.06 and 0.96 ± 0.05 & 0.97 ± 0.05 respectively). The CI was found to be 0.97 ± 0.16 for the PTV70. Conclusion: An average D2 was found to be 107% for high-risk target volume and 111% for both intermediate and low-risk target volume while an average D98 was found to be 96% for all target volumes. An evidence for possibility to get a target volume dose homogeneity within 10 – 15 % in NPC is presented and the need for similar studies from other centers is emerging to confirm these findings.
        Speakers: Moamen M.O.M. Aly (1 Medical Physics Section, Radiation Oncology Department, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia.3 Radiotherapy and Nuclear Medicine Department, South Egypt Cancer Institute, Assiut University, Assiut, Egypt.) , Mukhtar Al-Shanqity (1 Medical Physics Section, Radiation Oncology Department, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia.)
      • 75
        Conformal and intensity modulated radiotherapy in head and neck cancer in South America
        Introduction: Head and neck carcinomas are a group of malignant tumors with a common location. Conformal Radiotherapy and Intensity Modulated Radiotherapy conform the dose and protect organs at risk. A descriptive study of patients with squamous cell carcinomas of the head and neck treated with these radiations techniques in South America was conducted. Materials and methods: A retrospective observational study was realized. Cases were defined as adults with histology diagnosis of head and neck carcinoma in all stages, treated with Conformal Radiotherapy or Intensity Modulated Radiotherapy in the Instituto Nacional de Cancerología, Bogotá, D.C., between January 2005 and December 2012. Information about social, demographic, clinical variables, complications and outcomes were recorded. Kaplan-Meier test was done for overall and free-progression survival. Results: 59 patients were included (69.5% men). 20 patients received 3DCRT and 39 patients received IMRT. The median total dose received was 66 Gy. 96.6% of patients presented acute complications during treatment. 100% of patients treated with 3DCRT and 94% of patients treated with IMRT presented any acute complication. 40% of patients treated with 3DCRT and 15.4% of patients treated with IMRT. More common toxicities were radiodermatitis and mucositis. 52.5% of patients have late complications. 50% patients in 3DCRT group and 51.3% patients in IMRT group have a complete response. Mean overall survival rate was 42.7 months (CI 95% 24.5-60.7 months) in 3DCRT patients and 46.4 months (CI 95% 37.4-55.4 months) in IMRT patients. Mean relapse free survival rate was 42.8 months (CI 95% 25.2 to 60.4 months) in 3DCRT patients and 59.9 months (CI 95% 25.2 to 60.4 months) in IMRT patients. Conclusion: Patients with head and neck carcinomas treated in our center with 3DCRT or IMRT showed outcomes compared to others studies reported, prospective studies are still needed to proved benefit of IMRT over 3DCRT.
        Speaker: Martha Cotes (Instituto Nacional de Cancerologia, Bogotá)
      • 76
        Potential biomarkers for personalized oncology radiation in uterine cervical cancer
        Uterine cervical cancer (UCC) is one of the most prevalent malignant neoplasms in the world. UCC develops beyond the stage in situ and is frequently treated by a combination of intracavitary radiation therapy and external beam radiation therapy; 30 to 40% of patients with similar prognosis factors not respond equally to a comparable standard treatment. Therefore, the study and identification of prognostic biomarkers, which indicate the probable course of the disease in an untreated individual, and predictive biomarkers, which allow identification of subpopulations of patients most likely to respond to a given therapy, would be extremely useful in the selection of patients for the development of innovative and effective therapies for locally advanced, metastatic and refractory uterine cervical cancer. A comparative analysis of UCC in the context of other cancers may reveal that it is relatively smaller number of targeted molecular agents that have been tested. Some studies indicate that there may be a significant association between the response to treatment and the tumor phenotype, characterized by changes in gene, protein and metabolic expression. The phenotypes that characterize the tumor microenvironment are hypoxia (HIF-1α), glycolysis increase (GLUT1, HKII, GAPDH) and acidosis (CAIX). Activation of the IGF system (IGF1, IGFII, IGF1R) by ionizing radiation induces accelerated cellular senescence. Activation of IGF-1R can result in signaling through two pathways, PI3K/AKT and Ras/MAPK, and as a consequence increases proliferation, protein synthesis and glucose metabolism, and decreased apoptosis. The development of therapeutic approaches directed against IGF1R and signaling pathways related to accelerate cellular senescence can reduce radiation-mediated tissue damage. IGF1R&EGFR may be considered as potential targets for radiosensitization within DNA repair pathways. Within work that we have been developing, reported that gene expression of IGF1R is a strong predictive marker for lack of response to radiotherapy (p=0.018, 95% CI(1.7-41.2)), patients (HPV16 (+), European variants (+), Non-European variants (+)) have 28.6 times higher risk of failure treatment; the presence of anemic hypoxia (hemoglobin (Hgb) ≤11 g/dl) and the expression of GLUT1 and/or HKII influence treatment response and are associated with a lower overall and disease free survival; GAPDH overexpression and co-expressing IGF2 and IGF1R in the presence of Hgb≤11g/dl suggest a possible role of GAPDH as a regulator of tissue response to hypoxia (p=0.04). Objective: To determine whether expression of IGF-IR, GAPDH, HIF-1 alpha, Survivin, GLUT1, CAIX, HKII, presence of HPV16 variants and clinicopathological parameters can be used as prognostic and predictive biomarkers to treatment outcome and as possible molecular targets. Patients & Methods: This prospective cohort study included 149 patients with squamous cell carcinomas of the uterine cervix in FIGO stages IIB (n=53) and IIIB (n=96) between 2008 and 2011. The mean age was 46 years. Of the 149 patients, 61 were treated with radiotherapy and 88 with concurrent radiochemotherapy. Expression of the proteins CAIX, GLUT-1, HIF1α, HKII, IGF-IRα, IGF-IRβ and Survivin, was determined by immunohistochemistry, and presence of HPV16 variants was detected by PCR-SSCP and Reverse line Blot in biopsies taken before treatment. Results: The highest increase was found in expression of GAPDH (100%), Survivin (87%), followed of, IGF-IRα (76.5%), IGF-IRβ (74.5%), IGF-IRα and IGF-IRβ concordance in the expression(73%), HIF1α (74.1%); strong expression was observed with low frequency for GLUT-1 (31.1%), CAIX (16.2%), HKII (10.6%). Hgb level was significantly correlated with treatment response (p=0.01). With a median follow-up of 2.1years, OS was decreased for patients over-expressing IGF-1R β (p=0.04). A similar trend with GLUT-1 over-expression was observed (p=0.18). The OS of the sub-group of patients with anemia (Hgb < 11g/dL) and concomitantly over-expressing IGF-1R and GLUT-1 was significantly decreased compared to the opposite control group (p=0.015). The European variants of HPV16 was identified in 88% and non-European variants in 12%. Greater presence of European variants E-350G and non-European (eg.AA) with overexpression of IGF1R in the non-complete response group compared to the complete response group was observed. Conclusions: The presence of E-G350 and non-european (eg. AA) variants and overexpression of IGF1R in the non-complete response group could be related with radio-resistance. The expression of GLUT-1, IGF-1R and Hgb (≤ 11g/dl) are associated with poor prognosis, and thus appear to be interesting biomarkers of radiation resistance. If pre-clinical studies suggested such proteins to be part of the biological pathways leading to radio-resistance, the present clinical study confirms their role among UCC patients. Using the expression of GLUT1, IGF-1Rß and Hgb (≤ 11g/dl) as therapeutic molecular targets could contribute to an appropriate therapeutic management as individualized neoadjuvant treatment.
        Speaker: Pablo Moreno-Acosta (Research Group in Radiobiology Clinical, Molecular and Cellular, National Cancer Institute, Bogota, Colombia)
      • 77
        Feasibility of 27 Gray in 5 daily fractions adjuvant radiotherapy in breast cancer ladies – 1st report from an Iraqi institution
        Background: Breast cancer (BC) is the most common cancer in Iraqi ladies and the need for the adjuvant (Adj) Radio-Therapy (RT) as part of the breast cancer treatment, is important in many of the cases. RT centers are few in this war-torn country (10 in total) and they are over-loaded with the cancer patients and under-equipped with the required machines and staff (16 functioning linear accelerators in total for around 35 million of population while the ideal requirement is around 70 machines, ie, less than 23% of the requirement). Subsequently, most of the patients have to wait for long time reaching to eight months in our center in order to get the treatment, and few are being able to travel abroad to seek the required care in-time. The standard Adj. RT in BC is ranging from 40 Gray (Gy) / 15 fractions (fr) / 3 weeks (wk) as in the British institutions, to 50 Gy / 25 fr / 5 wk as in the American institutions. The practice of short-course adj. RT in BC (5 fr, once a day, over one week or once a week over five weeks, to a total of 26 - 30 Gy) has been studied previously by some colleagues and was a reasonable option in general, this is beside the extensive studies in Accelerated Partial Breast Irradiation approaches via brachytherapy or external beam radiotherapy. By mid of 2016, we launched a short course protocol in breast RT and we would like to share our modest knowledge here, as we feel that its feasibility outcomes can be of interest to some colleagues in RT community who are facing similar challenges. Methods: Descriptive report of the patients who received Adj. RT for BC, in a dose of 27 Gy in 5 daily fr., in Zhianawa Cancer Center (ZCC). Field of radiation was either whole breast or chest wall, with or without regional nodes with an additional boost as indicated. Tolerability of this study was assessed by checking the willingness of the participants to be managed in this approach. The trial design is a single arm feasibility study. Primary end point was the percentage of patients receiving the full course of treatment as planned. We assumed that more than 80% [CI: 60-80] of the participants will tolerate and complete the full course. We estimate that we will have 0.9 power to demonstrate the feasibility using 45 number of patients. The protocol concept of the study was discussed at / and accepted by the ASCO International Clinical Trials Workshop (ICTW) in Istanbul, May 7-8, 2016 and we started to recruit patients after that. Results: 20 ladies with a mean age of 51 year (range 27-79) were managed according to this study for curative adj. intention during the period of June to early November 2016 (the remaining 25 required patients will be collected in the coming months till the time of the ICARO in June 2017). Half of them underwent breast conserving surgery (BCS) and the other half with modified radical mastectomy (MRM). 90% with invasive ductal carcinoma (IDC) and 50% with grade II and 55% of right side BC. All received 27 Gy in 5 fr. (5.4 Gy daily fr. size) in one week and 4 of them received an additional boost that ranged from 3-4 Gy times 3 fr. All the patients tolerated the treatment well without any interruption (100% compliance from the starting date to the date of the last fraction). Conclusions: In this provisional report, 27 Gy in 5 fr. seems a feasible approach in BC to deal with the great shortage of RT machines in Iraq in general and in ZCC in particular. In spite of the scarce literatures in this approach, our study revealed that this fractionation is well tolerable with encouraging outcomes. Further follow-up is required in our study and more international phase three trials are warranted in this regard.
        Speaker: Kamaran A. Mohammad (Zhianawa Cancer Center)
    • Session 8 - Education and training

      Learning objectives:
      1. Compare national and international challenges in education and training of radiotherapy professionals
      2. Discuss solutions and perspectives of education and training of radiotherapy professionals
      3. Analyse the role of technology in education and training and professional development

      Conveners: Giorgia Loreti (IAEA) , Ms Mary Coffey, Mr Oleg Belyakov (IAEA) , Mr Richard Poetter
      • 78
        IAEA Education and Training activities in Radiotherapy
        Speaker: Giorgia Loreti (IAEA)
      • 79
        ESTRO - School
        Speaker: Mr Richard Poetter
      • 80
        ICTP, Trieste University, italian and croatian medical physics: a training opportunity for young physicists from developing countries
        Introduction The Abdus Salam International Centre for Theoretical Physics (ICTP) and the Trieste University have initiated in 2014 a Master of Advanced Studies in Medical Physics a two-years training programme in Medical Physics. The programme is designated to provide young promising graduates in physics, mainly from developing countries, with a post-graduated theoretical and clinical training suitable to be recognised as Clinical Medical Physicist in their countries. Presently, the 3 cycles of the programme have seen 49 participants from 33 Countries: Africa (19), Asia (11), Central and South America (14), and Europe (5), selected from more than 400 applicants per year. Scholarships are awarded to candidates from developing countries with support of the IAEA, TWAS (Third World Academy of Sciences), KFAS (Kuwait Foundation for the Advancement of Sciences), ACS (American Cancer Society), IOMP, EFOMP and ICTP. Material and methods The programme is developed following the recommendations of IOMP and IAEA for education and clinical training. In the first year 332 lectures and 228 hours of exercises are devoted to all main fields of medical physics: Anatomy and physiology as applied to medical physics, Radiobiology, Radiation physics, Radiation dosimetry, Statistics, Monte Carlo simulation, Physics of nuclear medicine, Medical physics imaging fundamentals, Physics of diagnostic and interventional radiology (X rays, US, MRI, Hybrid systems), Physics of radiation oncology, Radiation protection, Information technology in medical physics. Each course has a final written or oral exam. The second year is spent in one of the 19 Medical physics department of the hospitals’ network for the clinical training in: radiation oncology or diagnostic and nuclear medicine, on a programme developed adapting the IAEA (TCS 37, TCS 47 and TCS 50) and the AFRA guidelines. The clinical training is developed following a pre-defined Portfolio of activities, adapted for each Resident according to their previous experience in the field. The recommended time devoted to each sub-topic of Radiation Oncology is reported in the table 1. Conclusions IOMP, EFOMP and IAEA are seeing this initiative, a unique experience at the world level, as an answer to the growing demand of Medical Physicists in developing Countries. The programme has been recently received an international accreditation by IOMP and represents an important contribution of the European medical physics community to the development of medical physics in the developing world.
        Speaker: Renato Padovani (ICTP)
      • 81
        Accreditation of education and professional standards of medical physicists
        Introduction Medical physicists practicing in clinical environment, as defined by IOMP and in IAEA International Basic Safety Standards 2014, are health professionals with education and specialist training in the concepts and techniques of applying physics in medicine, competent to practice independently in one or more of the subfields of medical physics. The need for medical physicists and their important roles and responsibilities in radiation oncology are well defined by IOMP and in IAEA Human Health Series No. 25. Medical physicists practicing in radiotherapy are key members of an interdisciplinary team in the radiation oncology department dedicated to providing safe and effective treatment of cancer. Their ability and performance has a direct impact on the quality and safety of the radiotherapy services. Hence, they should be well qualified with professional knowledge and competence and be able to apply appropriately and effectively the principles of radiation physics in the clinics and to make major contribution to radiotherapy service. IOMP advocates the need for medical physicists practicing in medical institutions be qualified by going through an appropriate system of education, professional training and professional accreditation in a similar manner as other health professionals. IOMP also advocates the need for all medical physicists in different parts of the world to be qualified in a similar manner and practicing with the same standard of professional competency. The work of the IOMP pertaining to maintaining a high standard of practice by the medical physicists across the world is described in this presentation. Methodology A global uniformity in standard of practice of the medical physicists is important in the battle against cancers as this ensures that all patients can receive safe and effective treatments. To achieve this objective, there is a need to apply and maintain equivalent standard of education, training and professional development for medical physicists in different countries. Unfortunately, as reported by IAEA Human Health Series No. 25, there is a large variation in the requirement and format of education and training for medical physicists from different countries. Although, guidance on education and professional training of medical physicists has been issued by IAEA and IOMP, formal education and clinical training of medical physicists are yet to be established in many countries. IOMP in collaboration with a number of its member organizations established an international system of professional certification, the International Medical Physics Certification Board (IMPCB). Medical physicists certified by the IMPCB for instance in radiation oncology physics are considered qualified to practice independently in this sub-fields of medical physics. IOMP considers it more appropriate for medical physicists to be certified by their own national certification board as this could incorporate in the certification examinations country specific requirements and characteristics, such as local regulatory requirements, country specific clinical practice, and national language. Instead of certifying the individual medical physicists, IMPCB conduct accreditation on national certification boards. Only in situations where formation of national certification board is impractical, e.g. due to small number of practicing medical physicists, that IMPCB may consider certifying individual medical physicists. In addition, IOMP recommends that medical physics education and training programmes be subject to independent accreditation or audit. Such activities exist in a number of developed countries, but do not exist on international level. The Organization has established an Accreditation Board for accreditation of medical physics education programme. The Board has completed a pilot accreditation on established programmes. Full implementation of the accreditation programme will soon be launched, what will greatly help maintaining the medical physics educational standards in many small countries. IOMP is also considering to set up in future an Accreditation Board for audit of medical physics clinical training programmes. As stated in its Policy Statement No. 2, IOMP considers continuing professional development (CPD) an essential part of the professional credential of the medical physicists. The quality of the CPD programme on offer to medical physicists by a national organization is evaluated during accreditation of national certification board. Conclusion In an attempt aiming to improve the standard of practice of the medical physicists to better support radiation therapy service and other medical physics activities on a global basis, an international system of quality audit on standard of education, training and professional practice of medical physicists is being implemented by IOMP. The audit system consists of three parts, namely, (1) professional certification of medical physicist and this has already been implemented by IOMP in collaboration with IMPCB; (2) accreditation of medical physics education programmes and a pilot run of this has been completed by IOMP; and (3) accreditation of medical physics clinical training programmes, a future task of the IOMP. These audit programmes will likely have significant positive impact on standard of practice of the medical physicists and quality of radiation therapy service across the world.
        Speaker: Kin Yin Cheung (International Organization for Medical Physics (IOMP))
      • 82
        Addressing global radiation medicine human resource gaps through educational innovation
        Background: With the rapidly growing number of cancer patients globally, addressing gaps in cancer care services is now an acute need. Radiotherapy is critical to the management of cancer patients. However, the majority of patients in low-income countries do not have access to radiotherapy. The gap in radiotherapy access around the world is huge and there is a need for >200,000 new health professionals by 2035 to meet the demand for radiotherapy services (Lancet Oncol, Sept 2015). We considered the challenges and gaps in health professional training using current training models and the opportunities to address this health human resource shortfall through innovative educational methods, models and technology. Methods: To address the current and growing gaps in available health professionals we have an obligation to explore innovations in all aspects of education and re-imagine curricula from the current “industrial model” into a “systems-based” (Frenk, Lancet, 2010) approach using a competency-based foundation. Traditional professional boundaries and scopes of practice must be challenged and new scopes of practice defined. New training models should leverage local skills and leadership while promoting global credentialing and practice standards. These models will promote local talent retention and expansion. Results: The authors propose to explore and pilot new educational models to address three main areas for innovation: 1) professional scopes of practice and task shifting; 2) a systems-based competency model for curriculum development and 3) maximized use of educational technology in a blended curriculum. Professional scopes of practice are evolving in multiple jurisdictions; e.g.; introduction of a Clinical Specialist Radiation Therapist (CSRT) program in Ontario, Canada, the incorporation of Physician Assistants into cancer in the United States, and the development and integration of automation technologies. The scope of practice for radiation medicine professionals must be reviewed in each local/regional context and task shifting or re-distribution of roles and responsibilities accomplished to maximize the use of scarce resources. Efficiency models may be used to simulate the optimal distribution of tasks among professionals and automated technologies. The principles of such new models should be to maximize high quality and safe radiotherapy delivery while maximizing resources and access to treatment. A systems-based core curricula grounded in competency-based principles should be developed to address the all aspects of the radiation treatment process for the new professional scopes of practice. This new curriculum should articulate the new professional roles in a care environment which is capitalizing on the use of automation technologies. This curricula should encompass global standards for cancer care while allowing for local and regional contextualization, customization and challenging the status quo. Innovative curricular models must be leveraged through excellent clinical teachers and rigorously tested and evaluated through educational research. The merits of global certifications, facilitating a portable radiation medicine workforce, in the local context should be explored. A train-the-trainer knowledge translation plan should be simultaneously developed with the curriculum to promote rapid expansion of human resources for cancer care by leveraging local expertise. Blended learning approaches are likely to maximize learning and the sharing of educational resources as global public goods. Blended learning is the combination of on-line or digital learning with face-to-face learning. To facilitate this a review of potential barriers to end-users of on-line/digital content in local environments is needed as well as proposed strategies to mitigate these barriers. The on-line/digital content requires a sustainability strategy and should be developed as global public goods without cost for use. Conclusions: The educational innovations outlined in this paper require local feasibility assessment and a systematic resource development plan to address expanding global shortages in health professionals and to address training disparities around the globe.
        Speaker: Meredith Giuliani (Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Canada)
      • 83
        Implementation of the Brazil’s National Training Program for Radiotherapy Technicians - Preliminary results
        INTRODUCTION In Brazil, there is a shortage of radiotherapy machine in relation to the number of cancer cases to be treated. To reduce patient waiting time, the Brazilian Ministry of Health has decided to buy eighty linear accelerators to be installed throughout the country. As consequence it became urgent to train professionals to work in these Health Facilities, such as radiological oncologists, medical physicists, radiotherapy technicians, nurses. In this way, the National Radiotherapy Training was conceived by the Cancer Foundation and developed in partnership with National Cancer Institute and Universidade Estadual do Rio de Janeiro in order to supplement the training and updating courses for radiotherapy area professional. OBJECTIVE The goal is to prepare professionals qualified to work in radiotherapy. Particularly, the Professional Qualification Course for Radiotherapy Technicians (PQCRT) will train 80 radiotherapy technicians, divided in four classes. METHODOLOGY The Program’s PQCRT has the characteristics: • 1040 hours of activities, divided into 3 Modules: - Basic (345 h): theoretical-practical - Intermediate (350 h): internship in teletherapy - Advanced (345 h): internship in advanced teletherapy and brachytherapy • Target audience: radiology technicians • Duration: four group of 20 students are distributed in two years with each course lasting six months After the Basic Module, the students were sent to several institutions to have the clinical experience under the supervision of a local preceptor. The coordinator and tutor of the course follows the students' performance through detailed weekly reports on the practices. The main objective is to reinforce all concepts, treatment techniques, in-depth safety barriers, information transfer, etc. The emphasis has been on detailing the processes in teletherapy and brachytherapy: Simulation, Planning, Treatment and patient care. In addition, they need to follow and describe the local Quality Assurance program with special attention safety barriers implemented during the treatment of the patient. The Intermediate and Advanced Modules are focused in the different phases of the radiotherapy routine process and reported weekly to the Coordinator. Local visits to the training site were conducted when needed. RESULTS The PQCRT finalized the first course 19 radiotherapy technicians. Evaluating the internship with weekly reports, many students became aware to the fact that what they learned in classes were not observed the health services where they trained. They began to describe, within each topic studied, what they had learned in the Basic Module comparing with what they were following in patients' treatments. What was be perceived is that many Brazilian radiotherapy services did not follow the national norms some of them presented below: • Fail to reproduce the simulation and treatment • Extremely short time scheduled to attend each patient. • Lack of information about simulation data in the Treatment Chart • The patient is not assisted when entering or leaving treatment. • Treatments with IMRT and RAPID ARC, sometimes are performed even with doubts about the procedure, endangering the quality of the treatment and the patient safety. • Generally, there is one technician per turn on each machine. • The technologist is the one who performs double check, not the second physicist. • In brachytherapy, when X-ray equipment was under maintenance, individual planning has not been performed, and only some templates recorded in the source to release system was being used. • Two scans are performed on computed tomography because the displacement is done with a ruler and redone for treatment area visualization. CONCLUSION The students finished the course with sufficient technical and physical background and can already work in the Radiotherapy Services. With the routine reports they presented, one may conclude that, there is an urgent need to implement a continuous education program to professionals already working in the radiotherapy centers. The results clearly show the lack of a comprehensive Quality Assurance Program in the services resulting in the expected positive clinical outcome and the patient safety. However, students who have successfully gone through the program, have shown sufficient proficiency to treat the patients with the working knowledge as required by the recommended quality standards of practice.
        Speaker: Tania Furquim (Cancer Foundation)
      • 84
        Competency-based education of RTT’s in Romania: changing the paradigm to prepare the future
        Background: In Romania cancer patient’s access to radiotherapy services is far below the standard of EU countries. Access to radiotherapy of cancer patients is currently approximately 30% compared to 47-50% according to international recommendations. Radiotherapy centers network in Romania is currently in development in both the public and private sectors. Cobalt devices have been replaced in most centers, 3D conformal techniques are standard in most of them and in some centers IMRT techniques are used. In these circumstances the training of human resources involved in radiotherapy services (doctors, medical physicists, RTT’s) should be a major concern of universities and other institutions providing services is education. Competency based RTT’s education Traditionally RTT training in Romania was not specific for radiotherapy most of these specialists being educated as radiology technicians. University of Medicine and Pharmacy "Iuliu Hatieganu" in Cluj-Napoca is still educate since 2000’s radiology technicians in the frame of a study program of 180 European Credit Transfer and Accumulation System (ECTS) Beginning with the academic year 2016-2017 curricula of training of this study program was restructured to include more theoretical concepts and practical applications dedicated to radiotherapy. The total number of 180 ECTS is preserved and is performed over 3 years. The umber of hours of courses and internships to develop skills related to radiotherapy has been increased and represents 40 ECTS, which is double compared to the previous curricula. To establish the new curricula, the IAEA recommendation for training and education of RTT was used. The purpose of these changes was to provide future professionals a basic level of skills that enable them on the one hand a safe practice of radiotherapy activities and on the other hand to possess the cognitive skills necessary for lifelong learning in a professional environment in constant change. Beginning in academic year 2017 is scheduled to introduce a master program degree study for RTT’s order to increase competencies specific to radiotherapy after graduation. Conclusion The development of technical infrastructure of radiotherapy departments in Romania requires adapting the educational offer to the needs of the labor market. RTT’s must have knowledge and practical abilities to adapt to a complex work environment. At the University of Medicine and Pharmacy in Cluj Napoca there is a study program of 180 ECTS that has been modernized starting with academic year 2016 to include an increased number of courses and practical activities dedicated to radiotherapy. It is so far the only University in Romania that offers such a program of study and we believe that extending it to other Universities will be mandatory in the coming years as a necessity required by the practical realities of the development of radiotherapy activities.
        Speaker: Ioan Valentin CERNEA (University of Medicine and Pharmacy "Iuliu Hatieganu" Cluj-Napoca, ROMANIA)
      • 85
        Competency based education and training in radiation oncology
        Introduction As in any field, errors happen in radiation oncology despite our best efforts to prevent them. It is well known, and well documented, that appropriate, adequate training can reduce the likelihood of errors.. The World Health Organization (WHO) published the manual Radiotherapy Risk Profile in 2008 and in this manual it lists competency assessment as one of the top three interventions that is likely to be an effective safety barrier. But what is competence? Competence is the ability to do something successfully and efficiently. Hence, competency based education and training must offer comprehensive training as well as be able to determine whether an individual can successfully complete a task independently and do so in an efficient manner. Radiation oncology is a technology centered specialty that is continuously evolving and requires continued education and training to stay up to date with current technology, improved techniques, and/or to increase efficiency as well as improve overall safety. Methodology An online system was setup in order to establish specific training modules and track users’ progress throughout their competency development. Various media was used to convey information to users such as text files, presentation slides, and videos. Additionally, certain modules included quizzes based on educational material as well as assigned clinical observations where an individual would be followed and assessed in the clinic for a particular procedure. To test which media was most effective at communicating information, members of the department of radiation oncology was randomly assigned to 1 of two groups. Each group was assigned a general radiation safety module, where one group’s assignment was text/slide based and the other group’s assignment was video based. Each group had the same quiz administered after the content was reviewed. Additionally, brachytherapy modules were given to new medical physics residents with no prior brachytherapy experience. Program compliance and overall assessment was measured and residents were surveyed about the program. Results The online system was deployed in the department with various module assignments given to specific groups. Various metrics were measured including program compliance, individual assessment after the program (competence), and survey feedback from users and will also be discussed. Conclusion An online competency based education system utilizing multimedia content, along with hands on assessment, is an efficient and effective tool to implement in radiation oncology.
        Speaker: Daniel Scanderbeg (University of California, San Diego)
      • 86
        International Radiotherapy Plan Competition: A step towards better planning and global transfer of knowledge
        Purpose: The quality of any plan for a radiotherapy patient is as good as the planner. Achieving optimum plans require both knowledge in the capabilities of the treatment planning system (TPS) and the clinical expertise of the planner. The aim of this competition is to challenge planners worldwide to do their best plan and then compare their dose objectives with others using the same or another TPS. Global transfer of knowledge is then shared through webinar sessions in which top planners from each TPS category share their planning tips and techniques. The major outcome of this initiative is to distribute global knowledge and best practices among the radiotherapy planners, which will lead to better plan qualities for cancer patients. in the whole world, knowledge sharing is worldwide and so is the impact. Methods and Materials: A left sided breast case with axilla and supraclavicular lymph nodes was put for the challenge. The dose scheme is 50 Gy to PTV_TOT_EVAL delivered in 25 fractions. Around 400 participants from 50 countries have registered from different geographic regions (36% from Asia, 4% from Africa, 38% from Europe, 5% from South America, and 10% from North America). The quality metrics, generated by the Plan IQ software (Sun Nuclear Corp.) were extracted from the RTOG protocol 1304 with even tighter tumor conformity and homogeneity indicators and tighter organ at risk (OAR) sparing criteria. All participants received the same dataset package: The CT DICOM image set, DICOM structure set, set of dose quality metrics, and the general planning rules that define certain practical aspects of the plan, i.e. allowed max number of fields, field arrangements and angles, energy, dose calculation algorithm, use of advanced heterogeneity correction, and size of dose calculation grid. The participants were given two weeks to submit their plans, which were evaluated by the PlanIQ software and were given scores out of 100 points. Results: Around 220 plans generated by different commercial TPS’s, Varian-Eclipse, Elekta-Monaco, Philips-Pinnacle, Accuray-Tomotherapy, RaySearch-RayStation, and others. Of which, only 180 plans were evaluated using the Plan IQ software. The plans submitted per TPS were as follows: 93 Eclipse plans (51.6%) 30 Monaco plans (16.7%), 19 Pinnacle plans (10.5%), 13 Tomotherapy plans (7.2%), 10 RayStation plans (5.6%), and 15 plans from other vendors (8.3%). The scores’ statistics per TPS were as follows: Eclipse’s mean score was 58.3% (STD= 13.5% with mean deviation of 11.1%); Monaco’s mean score was 62.1% (STD= 13.8% with mean deviation of 10.9%); Pinnacle’s mean score 73.1% (STD= 17.4% with mean deviation of 13.9%). RayStation’s mean score was 89.6% (STD= 11.3% with mean deviation of 8.4%); and for Tomotherapy the mean score was 66.5% (STD= 20.1% with mean deviation of 16.7%). The highest score was 98.2/100. Following the announcement of the results, a series of webinars was arranged with the 3 top planners from each TPS category. The webinars are free of charge and were attended by planners using the same TPS as well others who wanted to learn planning tricks. Each webinar lasted for 1 hour, 20 minute per presenter, followed by questions and answers session. The feedback from the participants was overwhelmingly positive in regards to the knowledge shared that a WhatsApp group was initiated in which participants and others who came later keep on sharing their questions and solutions when it comes to clinical treatment planning. A youtube channel was also initiated to allow others to watch the webinars and other materials. Conclusions: In the 21st century knowledge transfer and learning is not confined to physical sites. We have initiated a plan competition that metamorphed into a truly global knowledge sharing and training tools. We noticed that the competition raised the awareness of TPS capabilities and participants who scored low have resubmitted plans that got high scores. Social media was used to create a community of planners to keep the momentum of learning and knowledge transfer going strong. In 2017, another case will be presented in the 2nd edition of the plan competition and this will kick start another round of educational webinars. Our aim is to hold these competitions and the subsequent educational webinars annually, each competition will feature new difficult cases or testing new features of TPSs such as the auto-planning capability. The ultimate goal is better patients’ plans through increasing both clinical and TPS knowledge.
        Speaker: Ahmad Nobah (King Faisal Specialist Hospital & Research Centre)
      • 87
        Questions and answers
    • Session 9a - From GTV to PTV M3


      Learning objectives:
      1. To understand the basic ICRU concepts in volume definition
      2. To learn about the various methods for volume delineation

      Conveners: Mr Alfredo Polo (IAEA) , Dr Nuria Jornet
      • 88
        Revisiting ICRU volume definitions
        Speaker: Dr Eduardo Rosenblatt (IAEA)
      • 89
        How to incorporate clinical information and natural tumor history in CTV definition
        Speaker: Mr Kenneth Hu
      • 90
        ITV and PTV margins for IGRT
        Speaker: Mr Joep Stroom
      • 91
        Autoplanning in the IGRT era
        Speaker: Mr Ben Heijmen
      • 92
        Questions and answers
    • Session 9b - Small field dosimetry

      Learning objective:
      1. Learn about the new IAEA/AAPM small field Code of Practice

      Conveners: Prof. Jan Seuntjens (McGill University) , Dr Karen Christaki (IAEA)
      • 93
        Physics of small fields
        Speaker: Prof. Pedro Andreo (Karolinska University Hospital, Stockholm, Sweden)
      • 94
        Small field Code of Practice
        Speaker: Mr Hugo Palmans
      • 95
        Questions and answers
    • Session 9c - Radiotherapy Plan Competition Initiative M2


      Conveners: Dr Ahmad Nobah, Giorgia Loreti (IAEA)
      • 96
        Radiation Knowledge Initiative
        Speaker: Mr Ahmad Nobah
      • 97
        2017 Radiotherapy Plan Competition
        Speaker: Mr Ahmad Nobah
      • 98
        Winners Announcements
        Speaker: Mr Ahmad Nobah
      • 99
        Radiation Knowledge ... What's Next?
        Speaker: Mr Ahmad Nobah
      • 100
        Questions and answers
    • ICEC M2


      Closed meeting

      Convener: Dr Norman Coleman
    • Session 10a - Breast and Cervix

      Learning objectives:
      1. To learn latest developments in radiotherapy for breast cancer
      2. To learn latest developments in radiotherapy for cervix cancer

      Conveners: Mr Brendan Healy (International Atomic Energy Agency) , Dr Elena Fidarova (IAEA) , Dr Gerry Hanna, Dr Richard Potter
      • 101
        Recent advances and current status of radiotherapy for breast cancerCurrent status of radiotherapy for breast cancer
        Speaker: Mr Gerard Hanna
      • 102
        Left breast radiation therapy - institutional analysis of doses to heart and LAD
        Background. Respiratory motions and free breathing during radiation therapy treatment of sites in the proximity of lungs, influence significantly on treatment of tumor volumes (in terms of sizes of PTV margins and also in possible under dosage of tumor volumes). It also influences the dose received by normal tissues surrounding the tumor volumes. This is particularly important in patients undergoing radiation therapy of the left breast, since these patients have long life expectancy in one hand, and on the other hand, the unintended irradiation of the heart and LAD artery, may cause later cardiac failure and other cardiac side effects. Since one of four cancer patients, in Serbia and its northern province of Vojvodina, in female population is suffering from the breast cancer, and approximately half of them are left breast patients, we have conducted retrospective analysis of treatment plans of patients treated in our center in 2007-2010. These patients will be examined by cardiologists in following 3 years, and their current status evaluated, and if necessary treated cardiologically in order to prevent cardiac failure or other cardiac problems. Another prospective study which follows in future months, will show how current practice in radiation therapy treatment planning is reflecting in the doses to critical organs, and this will be also presented to public. Another step which is planned to be conducted based on the results of the study, is to prepare protocol and implement the deep inspiration breath hold, for the left breast patients whenever possible, in order to exclude the critical structures from the treatment field. Methods and materials. The patients presented in this study were treated during 2009. Treatment was delivered by linear accelerators of Radiotherapy Clinic, Institute of oncology Vojvodina, Sremska Kamenica. The machines were manufactured by Varian Medical Systems, and accelerators are of series 2100C and 600 DBX. The treatment planning system used, was of manufacturer Elekta, XIO v 4.62. The treatment planning system was verified according to the IAEA recommendations, and machines are regularly calibrated, and checked biannually in IAEA TLD audits. There were in total 114 left breast patients in 2009, of which 92 could be successfully de-archived 7 years after treatment, and returned to treatment planning system, without any error during de-archiving procedure. Since at the time of treatment planning for these patients, in 2009, the LAD artery was not delineated, the radiation oncologists delineated LAD structure on de-archived plans as they could recognize it, or where it should be anatomically (if not visible), and re-delineated heart, according to current practice and protocols at the Institute. Accordingly, the treatment plans were re-calculated and reviewed by medical physicists, to obtain doses to these two new structures, and results noted. Results. The results of evaluation of radiation therapy treatment plans, of left breast patients, whose patient plans were generated during the period January 1st 2009-December 31st 2009 are presented. The patients were prescribed different therapeutic doses, from 50 Gy to 60 Gy, depending on the stage and type of illness. The dose range to the heart was maximum 62.4 Gy and minimum dose was 3.6 Gy, while mean dose to heart as whole organ was 3.9 Gy. The mean volume of the heart was 687 cm3. As for the left lung, the maximum dose found was 65.5 Gy, minimum dose 0 Gy, and mean dose 6.9 Gy. Left anterior descending artery (LAD), which was newly delineated, after the de-archiving of the treatment plans, has received a dose range of: maximum dose 62.1 Gy and minimum dose 0.2 Gy, while mean dose was 20.3 Gy. The volume of delineated LAD was 4.8 cm3. We did not record distances of the heart to the treatment field edge at this stage, which will be done in the next weeks. Discussion. Breast cancer is the most common cancer throughout the world female population. It is nowadays illness which can be treated successfully, and life expectancy is long after treatment. If a patient is treated in such a way that she is free of cancer after treatment, and another life threatening illness is caused by the treatment of primary disease, then the result of cancer treatment is practically annulled. The dose to the neighbouring tissues depend mainly on anatomical structure of the patient, but there are now techniques which can improve the outcome to heart, LAD and lungs, as the most affected organs. This study will be continued, and these results are preliminary.
        Speaker: Borislava Petrovic (Institute of oncology Vojvodina, University of Novi Sad, Novi Sad, Serbia)
      • 103
        “Hybrid” 3D/VMAT technique for irradiation of patients with breast cancer and unfavorable anatomy. Preliminary dosimetric study.
        Introduction. Breast cancer irradiation improves local control and survival. Currently, there is a tendency towards an increase of full node irradiation (FNI), including the fossa supraclavicular nodes, with or without axillary nodes and the internal mammary nodes (IMN), even for early stage, high-risk patients. However, besides the low morbidity of this approach, most of the patients may present a long life-expectancy (> 10 years) and are at higher risk for late toxicity with the larger irradiated volumes. The objective of this study was to perform a dosimetric comparison between a “hybrid” volumetric modulated arc technique (3D/VMAT) and 3D conformal technique in the irradiation of patients with breast cancer where FNI was indicated. Methodology. Five patients with indication of adjuvant radiotherapy of the breast or chest wall and FNI were evaluated. Three presented left side disease. Contours were based on the RTOG recommendation. Planning target volumes (PTV) were defined with 5mm margin from the Clincal Target Volumes (CTV) and, when applicable, a 5 mm margin was cropped from the skin surface for dosimetric evaluation. PTV margins for the IMN were 3 mm. Prescribed dose was 50 Gy in 25 fractions (4 patients) and 50,4 Gy in 28 fractions (1 patient). All but one received a 10 Gy boost (5 x 2 Gy). Patients were first planned according to the departments’ routine: 3D conformal planning combined with modulated field-in-field technique. VMAT was indicated mainly when appropriate coverage of the IMN was not achieved with the 3D technique, respecting the organs at risk (OAR) constraints, due to unfavorable anatomy of the patients. A hybrid VMAT technique was developed and consists of two 3D conformal tangent fields delivering around 50% of the prescribed dose to the breast only and three partial VMAT arcs added to deliver the full dose to the IMN and fossa supraclavicular, and complement the dose to the breast. Patients were treated using image-guidance (IGRT). Eclipse v.10 planning system (Varian Medical Systems) was used for calculations with Analytical Anisotropic Algorithm (AAA). Results. Dose-volume histograms parameters with both techniques were generated and analyzed. Table 1 presents the results of targets coverage and dose at OAR using both techniques. Table 1. Mean values of the respective studied parameters (n = 5 patients). Dosimetric parameters 3D field-in-field Hybrid VMAT Relative difference (%) PTV D95 D90 D2 Dmax 45.2 Gy 48.7 Gy 61.6 Gy 62.9 Gy 45.5 Gy 47.7 Gy 60.8 Gy 64.5 Gy 0.7 - 2.1 - 1.3 2.5 SCN D95 D90 Dmax 45.6 Gy 46.9 Gy 48.6 Gy 49.3 Gy 50.4 Gy 50.8 Gy 7.5 6.9 4.3 IMN D95 D90 Dmax 31.4 Gy 36.2 Gy 56.3 Gy 46.5 Gy 49.3 Gy 59.2 Gy 32.5 26.6 4.9 Ipsilateral lung V5 V10 V20 Dm 53.1 % 50.2 % 42.6 % 21.0 Gy 93.1 % 59.1 % 30.3 % 15.9 Gy 43.0 15.0 - 40.6 - 32.1 Heart V10 V20 Dm 7.4 % 4.8 % 4.7 % 2.8 % 12.8 % 5.5 % - 164.3 62.5 14.5 Contralateral breast Dmax 36.9 Gy 18.6 Gy - 98.4 Contralateral lung V5 0.1 % 37.5 % 99.7 Both lungs V20 20.8 % 13.6 % - 52.9 Legend: PTV = Planning Target Volume; SCN = Supraclavicular ∕ axillary levels 2 and 3 nodes; IMN = Internal mammary nodes; Dxx = Dose received by xx% of the respective volume; Dmax = Maximum dose; Dm = Mean dose; Vxx = Volume that receives xx dose (Gy). Conclusions. Both techniques achieved adequate coverage of the breast or chest wall and the supraclavicular∕axillary nodes. However, IMN were better covered with hybrid VMAT. Overall, OAR dose constraints were respected, but V20 and Dm of the ipsilateral lung were higher with 3D technique. The lung volumes receiving low dose and the heart mean dose, independent of the side of disease, were higher with hybrid VMAT. On the other hand, contralateral breast maximum dose was lower with hybrid VMAT. Hybrid VMAT may be an option for better coverage of the IMN when FNI is indicated in patients with unfavorable anatomy.
        Speaker: Cecilia Maria Kalil Haddad (Sirio Libanes Hospital)
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        Recent advances and current status of radiotherapy for cervix cancer
        Speaker: Mr Richard Poetter
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        Nodal doses during image-guided adaptive brachytherapy for cervical cancer and implication to simultaneous integrated boost
        Purpose/Objective The use of image-guided adaptive brachytherapy (IGABT) in cervical cancer has allowed safer and more conformal delivery of higher tumor doses leading to better local control. The use of simultaneous integrated boost (SIB) to pelvic adenopathies is increasingly being used to improve regional control. Significant nodal doses during brachytherapy have been previously demonstrated and must be integrated in the SIB plan. This study aims to report the BT-delivered doses to adenopathies in different pelvic nodal regions and to propose SIB dose-fractionation regimens. Material and methods Patients with locally advanced cervical cancer comprising pelvic nodal involvement and treated with chemoradiation followed by image-guided adaptive pulsed-dose rate BT were included. During brachytherapy, GEC-ESTRO recommendations for target volume delineation and optimization constraints were followed. Nodal coverage was not included in the planning objectives. The adenopathies were delineated on 3-mm thick simulation scans to determine physical doses delivered. Physical D100, D98, D90 and D50 were reported and converted to 2-Gy equivalents (EQD2), using the linear quadratic model with an α/β of 10 Gy. Results Ninety-one patients were identified, allowing the evaluation of dose delivered in 226 adenopathies. The majority of the studied nodes were located in the external iliac (48%), common iliac (25%), and internal iliac (16%) regions. Overall, the EQD2 contribution was 3.6 ±2.2, 4.1 ±1.6, 4.4 ±3.3, and 5.2 ±3.9 Gy for the D100, D98, D90, and D50, respectively. The EQD2 D98 values were 4.4±1.9 Gy, 5.4±3.1 Gy, 4.3±2.1 Gy for obturator, internal iliac and external iliac nodes respectively, and 2.8±2.5 Gy for the common iliac. Whereas no significant difference was observed between the brachytherapy contributions of external and internal iliac nodes, the doses delivered in common iliac adenopathies were significantly lower (p<0.001). Furthermore, dose variations were noted among individual nodes within regions, due to differences in relative distances between the node and the implant. Legend to attached figure: Descriptive statistics of D98 of pathologic nodes according to regions. Ext: external iliac, Int: internal iliac, Ing: inguinal, Com: common iliac, Obt: obturator, Sac: presacral, Cent: central (pararactal or parametrial). Red cross: mean value, blue diamond: minimal and maximal values, lower limit of the box: first quartile, upper limit of the box: third quartile, central horizontal bar: median, whiskers: from minimal value to 1.5 x box length. Finally, to deliver a cumulative EQD2 ≥60 Gy to pathologic nodes accounting a pelvic external beam radiation dose of 45 Gy in 25 fractions (44.3 in EQD2) and these nodal dose estimations, we propose nodal SIB of 2.2 Gy x 25 (55 Gy, 55.9 in EQD2) in the obturator, external and internal iliac nodes, 2.3 Gy x 25 (57.5 Gy, 58.9 in EQD2) in the common iliac nodes, and 2.4 Gy x 25 (60 Gy, 62 Gy in EQD210) in the para-aortic nodes (where the BT contribution can be considered as negligible). Conclusion The contribution of brachytherapy to the treatment of pelvic nodes is significant - around 5 Gy in the obturator, internal iliac, and external iliac areas and 2.5 Gy in the common iliac, and should be considered in planning the simultaneous integrated boost. However, important individual variations have been observed and evaluation of the actual brachytherapy contribution is recommended.
        Speaker: Warren Bacorro (University of Santo Tomas Hospital - Benavides Cancer Institute)
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        Multi-institutional clinical studies of chemoradiotherapy for cervical cancer among Asian countries under the framework of Forum for Nuclear Cooperation in Asia (FNCA)
        The Forum for Nuclear Cooperation in Asia is a Japan-led cooperation framework for peaceful and safe use of nuclear science and technology in Asia. Eleven Asian countries have been participating in the project. The purposes of the project are to establish safe and effective treatments for predominant cancers in Asia and to improve the treatment outcomes. Since 1995, four international clinical studies of radiotherapy and chemoradiotherapy for cervical cancer have been conducted in the project. At the first clinical study, there were many difficulties, including wide differences in the cultural and socio-economic status among countries, wide differences in cancer imaging, poor compliance with the protocol, and poor follow-up rate. With the dedicated efforts of the study group members, the recent clinical studies of chemoradiotherapy (the 3rd and 4th studies) were well-controlled, and favorable treatment outcomes were obtained from the studies.
        Speaker: Shingo Kato (Saitama Medical University, International Medical Centre)
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        Dose-volume effects in pathologic lymph nodes in cervical cancer
        **Purpose/Objective.** The advent of intensity-modulated radiotherapy (IMRT) and image-guided adapted brachytherapy (IGABT) has allowed for safe delivery of higher doses in the treatment of locally advanced cervical cancer, translating to better local control. Moreover, nodal boosts are increasingly being used in order to improve regional control. However, while dose-volume relationships have been defined for the primary tumor and organs at risk, the optimal dose threshold for the treatment of pathologic lymph nodes remains uncertain. The objective was to identify planning objectives for pathologic nodes. **Material and Methods.** Patients with node-positive non-metastatic cervical carcinoma treated curatively with combined external beam radiotherapy (EBRT) and IGABT were identified. Pelvic EBRT was carried out to 45.0 - 46.0 Gy, using three-dimensional conformal radiotherapy (3DCRT) or IMRT techniques, with concomitant chemotherapy. Nodal boosts were performed sequentially or using the simultaneous integrated boost (SIB) technique depending on the EBRT technique used. IGABT was conducted within two weeks after completion of pelvic EBRT, using pulsed-dose rate (PDR) techniques and personalized vaginal mold applicators. The contributions of EBRT, IGABT (D98) and nodal boosts were converted in 2-Gy equivalent (α/β=10 Gy) and summated. The nodes were individually followed from diagnosis to relapse. Resected nodes during para-aortic node surgical staging were not considered. Statistical analyses comprised log-rank tests (univariate analyses), Cox proportional model (factors with p ≤0.1 in univariate), and Probit analyses. **Results.** One hundred and fifteen patients were included, with a total number of nodes of 288 (2.5 per patient). All patients had a staging CT and MRI. PET-CT was performed in 90.6% of the patients; para-aortic dissection in 53.8%. Histologic subtypes comprised squamous cell carcinomas (SCC) in 88.9%, adenocarcinomas in 8.5% and adenosquamous in 2.6%. The mean pathologic node volume at diagnosis was 3.4±5.8 cm3. The mean EBRT and nodal boost doses were 44.3±0.9 Gy and 10.0±2.9 Gy respectively. The mean IGABT contribution to pelvic nodes was 4.2±2.6 Gy. Finally the mean total dose to lymphadenopathies was 55.3±5.6 Gy. Concomitant chemotherapy was administered in 96.5% of the patients. After a median follow-up of 33.5 months, 20 patients (17.4%) experienced relapses in nodes initially considered pathologic at diagnosis (local relapse). Among them, recurrences were observed in a total of 44 nodes (15.3%). The mean time from treatment completion to relapse was 9.0±11.8 months. There was no significant relationship between the dose delivered to pathologic nodes and local control probability (p=0.38). Univariate analyses tested various factors: subtypes (SCC versus others, p=0.35), concomitant chemotherapy (p=0.39), use of SIB (p=0.07), volume at diagnosis (threshold: 3 cm3, p<0.0001) and dose (≥ 57.5 Gy, p=0.039). The last three factors were entered in a multivariate analysis. Volume (HR=8.2, 4.0-16.6, p<0.0001) and dose (HR=2, 1.05-3.9, P=0.034) remained independent, whereas SIB was not (p=0.99). Subsequent Probit analysis combining dose and volume showed significant relationships with the probability of local control (Figure). **Conclusion.** The initial volume was the main prognostic factor of control in pathologic lymph nodes. A dose superior to 57.5 Gy was also associated with a better local control probability. Further studies are required to refine these findings.
        Speaker: Warren Bacorro (University of Santo Tomas Hospital - Benavides Cancer Institute)
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        Questions and answers
    • Session 10b - Small field dosimetry

      Learning objectives:
      1.Review the ICRU small field dosimetry activities
      2. Implementation of small field dosimetry in the clinic

      Conveners: Prof. Jan Seuntjens (McGill University) , Dr Karen Christaki (IAEA)
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        Brief summary of IAEA/AAPM small field Code of Practice
        Speaker: Prof. M. Saiful Huq (UPMC CancerCenter)
      • 110
        Initial experiences in testing: the IAEA/AAPM code of practice on small field dosimetry
        **Purpose:** ------------ The International Atomic Energy Agency (IAEA) has established a coordinated research project focusing on clinical testing of the procedures described in the upcoming IAEA/AAPM code of practice on small field dosimetry. The initial task was the determination of beam quality based on square fields with different sizes using a standard MLC shaped 6 MV photon beams. Additionally, field output factors ($Ω_{Q_{clin},Q}^{f_{clin},f_{ref}}$) were determined for field sizes ranging from 10 x 10 cm² down to 0.5 x 0.5 cm². **Materials and Methods:** -------------------------- Thirteen participants from different countries were asked to experimentally determine the $TPR_{20,10}(S)$ or $\%dd(10,S)_{X}$ in a 4 x 4 cm² ($S=4$) and 6 x 6 cm² ($S=6$) 6 MV flattened photon field. The 4 x 4 cm² and 6 x 6 cm² fields were assumed to be "virtual" machine specific reference fields. The participants had to apply the formalism proposed in the IAEA/AAPM code of practice on small field dosimetry in order to determine $TPR_{20,10}(10)$ or $\%dd(10,10)_{X}$, respectively. These calculated beam quality specifiers were compared to the experimentally determined beam quality specifiers $TPR_{20,10}$ or $\%dd(10)_{X}$ determined in the 10 x 10 cm² field. Furthermore, the centers were asked to determine field output factors according to the IAEA/AAPM code of practice on small field dosimetry for field sizes ranging from 0.5 x 0.5 cm² to 10 x 10 cm² in a 6 MV flattened photon beam using at least three different detectors. For each center, the standard deviation with respect to the mean value of the field output factors measured with these three different detectors was calculated for each field as a measure for the agreement amongst the determined field output factors. **Results:** ------------ So far, the data of eight machines using $TPR_{20,10}$ and seven machines using $\%dd(10)_{X}$ were collected. The $TPR_{20,10}$ values ranged between 0.667 and 0.685 while the $\%dd(10)_{X}$ values ranged between 66.4% and 67.6%. The mean value of the differences between calculated $TPR_{20,10}(10)$ and experimentally determined $TPR_{20,10}$ in the 10 x 10 cm² field was -0.05% with a standard deviation of 0.4%. The mean value of the differences between calculated $\%dd(10,10)_{X}$ and experimentally determined $\%dd(10)_{X}$ in the 10 x 10 cm² field was -0.05% with a standard deviation of 0.6%. The differences of the individual centers did not exceed 1.1% and 1.2% for $TPR_{20,10}(10)$ and $\%dd(10,10)_{X}$, respectively. For the relative dosimetry task, the data of eight centers was been received so far. As depicted in Figure 1, for the majority of centers the standard deviations of field output factors was below 1 % over a wide range of field widths. An increase of the standard deviation with decreasing field width over the 1 % threshold was observed for five centers at a field width of 1 x 1 cm². For two of these centers the standard deviation dropped below 1 % at the 0.5 x 0.5 cm² field. In total, five centers submitted a sufficient number of field output factors for the 0.5 x 0.5 cm² field. The standard deviations of these field output factors was below 1%. **Conclusion:** --------------- The formalism proposed in the IAEA/AAPM code of practice on small field dosimetry for determination of beam quality in a 10 x 10 cm² based on experimental data in machine specific reference fields can be applied with a sufficient degree of accuracy. The slightly larger differences between the calculated and experimentally determined beam quality specifiers observed for $\%dd(10,10)_{X}$ might be related to uncertainties associated with automated scanning phantoms. The increasing variation of field output factors with decreasing field size might be attributed to positioning uncertainties of the detectors and uncertainties of the applied correction factors. Further investigation regarding this topic is necessary.
        Speaker: Wolfgang Lechner (Department of Radiation Oncology, Division Medical Physics, Medical University Vienna, 1090 Vienna, Austria)
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        Application of output correction factors for three small beam radiation detectors: comparison of results for a TrueBeam Stx linac
        Purpose ------- To compare and analyze the corrected out factors resulting from three different radiation detectors for small fields of a TrueBeam STx® linac. Materials and Methods ------- Detector signal ratios ($M_{Qclin}^{fclin}/ M_{Qmsr}^{fmsr}$) were measured for a 6 MV WFF (with flatting filter) photon beam of a TrueBeam STx linac. The following nominal square field sizes were used: 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, and 10 cm$^2$. The small fields were set by the jaw collimators and their actual size was verified and recorded. The radiation measurements were performed in liquid water at 10 cm depth with a source to surface distance of 100 cm. The detectors used were a synthetic diamond (model PTW-60019, manufactured by PTW-Freiburg, Germany), a mini-ionization chamber (model PTW-31016, manufactured by PTW-Freiburg, Germany) and a silicon diode detector (model SFD, manufactured by IBA-Dosimetry, Germany). The operation and characteristics of each detector can be found elsewhere on the literature. Each detector is referenced in this work by its commercial name: microDiamond (PTW-60019), SFD (SFD silicon diode) and PinPoint 3D (PTW-31016). A UNIDOS electrometer (PTW-Freiburg, Germany) was used to measure the detector signal. In the case of the ionization chamber, all the measured signals were corrected by the influence quantities. The signal ratios were corrected by applying the specific correction factors for each detector and field size. The output correction factors ( $k^{fclin,fmsr}_{Qclin,Qmsr}$ ) were taken from TABLE 26 of TRS 483 draft from a linear interpolation as a function of the actual field size used in this work. The msr field was set to 10 cm$^2$. The resulting corrected output factors were compared for each detector. The metrics used for comparison were the statistical dispersion of the data, and the mutual difference of the output factors ($\Omega^{fclin,fmsr}_{Qclin,Qmsr}$) for each detector. Also, a brief comparison of the output correction factors with the daisy correction method was performed for the 4 and 6 cm$^2$ field sizes. Results ------- The actual field sizes show a variation up to 10% for field sizes greater than 1 cm$^2$. For the smaller field size (0.5 cm$^2$), it was impossible to perform the measurement. This field size was redefined with different jaw settings to allow the measurement. The Figure 1a shows $M_{Qclin}^{fclin}/ M_{Qmsr}^{fmsr}$ as a function of the actual field size expressed as the equivalent square field size. It can be observed the typical behavior of the signal ratios for each detector. The differences between the measurements are greater for the smaller field sizes (< 1.0 cm2), up to 5.6% for 0.5 cm2 field size. The Figure 1b shows the corrected out factors ($\Omega^{fclin,fmsr}_{Qclin,Qmsr}$). It can be observed an agreement between the $\Omega^{fclin,fmsr}_{Qclin,Qmsr}$ better than 1% for all field sizes. However, it can be observed that the field size of 1.0 cm2 shows the higher dispersion of the results 0.8%. The mutual difference analysis shows that the microDiamond detector has a difference up to 2.3% relative to the other detectors at the 1.0 cm$^2$ field size. Also, the comparison of the daisy chain $k^{fclin,fmsr}_{Qclin,Qmsr}$ with those from TRS 483 showed a good agreement better than 0.7%. Conclusions -------- The application of the output correction factors to the signal ratio for each detector to obtain the corrected output factors, shows an overall excellent agreement (<1%) between the radiation detectors and field sizes used in this work. The 1.0 cm$^2$ field size showed the highest dispersion, 0.8%. The mutual difference analysis showed that the output factors measured with the microDiamond detector differ from the other detectors up to 2.3% for the 1.0 cm2 field size. The comparison of the daisy chain $k^{fclin,fmsr}_{Qclin,Qmsr}$ with those from TRS 483 showed a good agreement better than 0.7%. In the near future more detectors will be added to this work.
        Speaker: Jose Manuel LARRAGA-GUTIERREZ (Instituto Nacional de Neurologia y Neurocirugia)
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        Application of the PTW microDiamond in small field dosimetry on different accelerators: Comparative measurements and Monte Carlo calculations
        **Introduction -** Volume averaging and detector mass-density effects are crucial for dosimetry in radiotherapy photon beams with small field size. Although for solid state detectors as silicon diodes and diamond detectors the two effects tend to balance each other, correction factors are in general required for field output factor measurements of small beams. Recently several studies have been published on output correction factors for the PTW 60019 microDiamond (mD) and a good agreement is observed for results referring to field sizes down to 1 cm. On the contrary results for very small field sizes are sometimes controversial thus requiring further investigation. In this study output correction factors for the microDiamond are determined by Monte Carlo (MC) calculation and applied to detector measurements (OFdet) perfomed by a set of ten mD detectors, in 6 MV photon beams produced by different clinical accelerators. The study mainly aims at: i) assessing up to what extent the accelerator type and collimation choice affect the mD response; ii) evaluating the variability of the dosimetric properties among the investigated mD detectors; iii) checking the consistency of MC calculation for the mD by comparing the corrected OFdet results obtained both by the set of investigated mDs and commercial silicon diodes. **Materials and Methods -** 6 MV beams from three linear accelerators were used: a Varian DHX, an Elekta Synergy and a CyberKnife M6 system. Nominal square field-sides of 100, 60, 30, 16, 10, 8 and 6 mm were obtained from the Varian and the Elekta accelerators. For the CyberKnife system, circular beams with a field diameter of 60, 30, 15, 12.5, 10, 7.5 and 5 mm were obtained by using fixed collimators. The accelerator outputs in terms of absorbed dose to water in reference conditions were determined by means of a Farmer-type ionization chamber according to the IAEA TRS 398 dosimetry protocol. For CyberKnife, a specific MC correction factor was applied to account for the use of 60 mm diameter as reference field size. The mD detectors, provided with calibration factor in terms of absorbed dose to water for the Co-60 quality, were used in the clinical beams. Two PTW 60017 unshielded Ediodes were also used in the clinical beams for comparison. Using the Co-60 calibration factors and the measurements in the accelerator reference field, the variation of mD response from Co-60 quality to 6 MV clinical beams was evaluated. Field output factors were obtained from the ratio of the detector readings in the non-reference and the reference fields applying MC output correction factors specifically determined for each beam using the EGSnrc code. The 6 MV beams produced by the three accelerators were independently simulated by means of the BEAMnrc code. The phase-space files obtained for all the field sizes considered for experimental measurements were used as input sources in the EGSnrc/egs_chamber code for calculating the output correction factors of the two types of detectors. To this purpose, the mD and the Ediode were modelled according to the blueprints provided by the manufacturer. The output correction factors were determined by calculating the absorbed dose in the detector sensitive volume and in a small voxel of water for the reference field and each non-reference field. **Results –** Very homogeneous results were obtained by the ten mD detectors, with a standard deviations of OFdet values within 0.5% for all the considered field sizes. A response variation of about 2% was observed between the Co-60 quality and the clinical 6 MV beams with a maximum deviation among individual detectors below 1%. Preliminary results on mD output correction factors show a weak dependence on accelerator type and collimation system. Correction factors are within 2% for field sizes down to 5 mm. Larger corrections, up to about 5%, were obtained for the Ediode. Applying the MC calculated correction factors, field output factors obtained by the mDs and the Ediodes agree within 1% for the CyberKnife system and preliminary results confirm such an agreement for the Varian and the Elekta accelerators as well. **Conclusions -** The results of this study show that very similar dosimetric properties are obtained from ten mD detectors, thus indicating a good reproducibility of their fabrication process. On the basis of the present results, the MC method is proved to be capable of providing reliable output correction factors for the mD detector. A set of mD output correction factors is provided, with an uncertainty estimate including contributions accounting for differences among individual detectors and beams produced with different accelerators.
        Speaker: Maria Pimpinella (ENEA - National Institute of Ionizing Radiation Metrology, I-00123 Rome, Italy)
      • 113
        Monte Carlo calculated correction factors for nine detectors in Leksell Gamma Knife Perfexion unit
        **Introduction:** The Leksell Gamma Knife (LGK) Perfexion unit is a radiosurgical device delivering a single high dose of radiation and small radiation fields. The dosimetry of LGK should be based on the formalism for the reference dosimetry of small and nonstandard fields since the reference conditions of TG-51 or TRS-398 cannot be established on this unit. There are few published studies on reference dosimetry of the LGK Perfexion. The goal of the present study is to calculate the $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ factors, introduced in the small field formalism, for nine detectors used in the reference dosimetry of the LGK Perfexion using Monte Carlo simulation. This study provides a comparison of EGSnrc and PENELOPE for the calculation of $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ factors for two possible orientations of the detector. **Methodology:** Nine chamber types including Exradin-A1SL, A14SL, A14, A16, IBA-CC04, CC01, PTW-31010, 31014 and 31016 were simulated in EGSnrc using the specifications provided by the manufacturers. Five of them including: Exradin-A1SL, A14, A14SL, A16 and IBA-CC04 were also modeled in PENELOPE. For the machine specific reference field (*msr*) set-up, the water phantom, the Solid Water phantom and the Elekta Acrylonitrile Butadiene Styrene (ABS) phantom were modeled as 16-cm diameter sphere made of water, Solid Water and ABS respectively. The reference point of the chamber was positioned at the center of each spherical phantom. In the ABS phantom, calculations were performed for two orientations of chambers with the chamber stem positioned parallel and perpendicular to the symmetry axis of the collimator block. The mean absorbed dose to the air cavity of chamber was calculated for both the reference set-up ($D_{\text{det},Q_{\text{0}}}^{f_{\text{ref}}}$) and the *msr* set-up ($D_{\text{det},Q_{\text{msr}}}^{f_{\text{msr}}}$). The dose to a 3 mm diameter spherical water volume was also calculated in both set-ups independently ($D_{\text{w},Q_{\text{0}}}^{f_{\text{ref}}}$ and $D_{\text{w},Q_{\text{msr}}}^{f_{\text{msr}}}$). Using the following equation and the mentioned quantities, $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ was determined. $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}} \approx \frac{D_{\text{w},Q_{\text{msr}}}^{f_{\text{msr}}}/D_{\text{det},Q_{\text{msr}}}^{f_{\text{msr}}}}{D_{\text{w},Q_{\text{0}}}^{f_{\text{ref}}}/D_{\text{det},Q_{\text{0}}}^{f_{\text{ref}}}}$ **Results:** Figure 1 shows the calculated $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ values for all chambers in the water phantom. The uncertainties on $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ factors shown in figure 1 are type A and less than 0.1% (one standard deviation). Depending on the chamber type, the difference between EGSnrc and PENELOPE data of this study varies between 0.02-0.49% in the water phantom. Given that both codes are algorithmically self-consistent with respect to their own cross sections (i.e., they pass the Fano test at the 0.2% level) and the geometries modeled were identical, this difference may be due to slight cross section differences or differences in cross section implementation details in both codes. The EGSnrc and PENELOPE calculated $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ values for all chambers in Solid Water and ABS phantoms are given in table 1. The difference between $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ values in parallel and perpendicular orientations is largest for PTW-31010 (3.5%) and 31014 (2.3%). It is smallest for Exradin-A1SL (0.4%) and A14SL (0.5%). This is due to the cavity lengths to radius ratio, which is the largest for the PTW-31010 and 31014 chambers as well as the fact that these chambers have electrodes made of Aluminum. **Conclusion:** $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ factors introduced in the small field formalism were calculated for nine detectors and three phantoms using Monte Carlo simulation. Good agreement is observed between $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ values determined with EGSnrc and PENELOPE. The %RMS deviation between EGSnrc and PENELOPE calculated $k_{Q_{\text{msr}},Q_{\text{0}}}^{f_{\text{msr}},f_{\text{ref}}}$ values for Exradin-A1SL, A14, A14SL, A16 and IBA-CC04 chambers studies in this work was found to be 0.4%.
        Speaker: Lalageh Mirzakhanian (McGill University, Medical Physics Unit, Montreal, QC H4A 3J1, Canada)
      • 114
        Influence of detector specific correction factors in dose distributions for small photon beams
        Introduction ------------ The problems related to the dosimetry of small photon radiotherapy beams are highlighted in the literature (Das 2008). To perform the dosimetry of such beams, the detectors employed with more frequency are silicon diodes. Nerveless, these detectors over-respond in non-equilibrium conditions. For that reason, it is necessary to apply correction factors according with the new formalism for small photon beam dosimetry. Particularly, the interest of this work is the application of the correction factors to depth and off-axis dose curves. The goal of this work was to assess the influence of theses correction factors in clinical dose distributions. Material and Methods -------------------- This study was divided in three steps: i) the collection of dosimetric data for circular collimators using a silicon diode (model SFD, IBA-Dosimetry, Germany), ii) the Monte Carlo calculation of depth and off-axis correction factors, and iii) the incorporation of the commissioning data sets into the planning system (iPlan RT 4.1, BrainLAB, Germany). The dosimetric measurements were performed in a Novalis® linac (BranLAB, Germany) with nominal energy of 6 MV. For calculating of correction factors the Monte Carlo codes used were DOSXYZnrc and DOSRZnrC. The parameters used for the simulation Novalis were: 6.1 Mev monoenergetic with a circular symmetric Gaussian FWHM for 1.5 mm. The correction factors were calculated based in formalism proposed by Alfonso et al, and Francescon et al. to the total scatter factors (TSF), tissue phanom-ratios (TPR) and off-axis ratios (OAR). Finally, a clinical treatment plan was simulated based on an arbitrary patient head. The calculated dose distributions in the treatment planning system was compared and analyzed as following: a) measured data sets and Monte Carlo calculations, b) dose distributions analysis with and without corrections factors and finally c) monitor unit (MU) analysis. Results ------- The correction factors calculated in this work show a similar behavior to those reported in the literature, a quantitative comparison was not possible because there are no data reported for the accelerator and detector used in this work. The comparison of measured data sets and Monte Carlo calculations was done by an analysis of percentage differences for TSF and TPR. Particularly for OAR, a gamma index 1D analysis was made and a full width at half maximum (FWHM), the 80%–20% penumbrae and 90%–10% beam penumbrae comparison. All results of these data sets show no significant differences. For dose distributions, the gamma index analysis criteria employed 1%/1mm, 1%/3mm, 1%/5mm, 2%/2mm, 2%/3mm and 3%/3 mm. In all case except in 1%/1mm, the gamma index analysis show that 100% of the points meet the established criteria. Finally, the results of MU show a percentage difference up to 6%. The UM analysis shown the biggest differences found in this study. Conclusions ---------- The new formalism for small photon beam established the necessary correct the response with a detector specific beam correction factors. In this work, evaluation of the influence of theses correction factors in dose distribution was performed. The biggest percentage difference was to MU. The rest of the analysis show no significant differences for the calculation dose distributions with and without correction factors. Therefore, these results suggest that the correction factors have influence on the TSF.
        Speaker: Olivia Amanda GARCIA-GARDUÑO (Instituto Nacional de Neurologia y Neurocirugia)
      • 115
        Nationwide audit of small fields output calculations in Poland
        Introduction Modern radiotherapy is mostly based on the modulation of the beam intensity and on the sterotactic dose delivery. These techniques require very accurate imaging of the patient and very accurate tumour delineation. They also require very accurate dose distribution calculation by the treatment planning systems (TPS). The calculation algorithms use the basic data such as multileaf collimator parameters and beam output factors. Of special importance are the output factors for small field sizes since they are extensively used in stereotactic techniques and in the intensity-modulated radiation therapy. Since the measurements of the output factors for small field size is not an easy task and cannot be properly performed in every radiotherapy facility, a set of such basic data would be of great value. Such a set of data has been prepared by the Radiological Physics Center (RPC), the University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA) and published by Followill et al. The RPC has gathered multiple small field size output factor datasets for X-ray beam qualities, ranging from 6 to 18 MV, from Varian, Siemens and Elekta linear accelerators. These datasets were measured at 10 cm depth and ranged from 10×10 cm2 to 2×2 cm2. The RPC’s measured small field output factors provide institutions with a standard dataset against which to compare their TPS calculated values. Within the framework of the CRP E2.40.16 project "Development of Quality Audits for Radiotherapy Dosimetry for Complex Treatment Techniques", run by the Health Section of the international Atomic Energy Agency (IAEA), a methodology of the audit of small field output performance was established. Material and Methods The participants had to calculate the output factors for the beams formed by the multi-leaf collimator (MLC), using their planning software. The results of their calculations were compared with the reference RPC data. All 35 Polish radiotherapy departments invited to take part in the audit, and 32 of them responded and provided their results. In Poland, there are medical accelerators from three manufacturers: Varian; Elekta, and Siemens. In total, 65 beams were audited: 20 from Elekta, 15 from Siemens and 30 from Varian accelerators. In some cases, the calculations were performed with different TPS or calculation algorithms for the same beams. The participants of the audit were asked to calculate the number of monitor units (MU) for the delivery of a prescribed dose to water with square fields of different sizes. A dose of 10 Gy was prescribed to a reference point at 10 cm depth on the central axis, at 100 cm source-to-phantom distance (SFD). The output factors for five field sizes, 10×10 , 6×6 , 4×4 , 3×3 and 2×2 cm2, shaped by a multileaf collimator (MLC), were calculated. Numbers of MU, obtained for specified field size f and beam quality Q, were then normalized to (divided by) the numbers of MU calculated for a field size of 10×10 and for the same beam quality, thus providing the normalized output factor. A number of treatment planning systems (TPS) were examined during the audit. The participants were obliged to use the clinically used TPS together with an approved beam model for the calculations. The following TPS and related calculation algorithms were examined : Monaco – Monte Carlo (MC), XiO – Convolution (CV) and Superposition (SP), Oncentra MasterPlan – Pencil Beam Convolution (PBC) and Collapsed Cone Convolution (CCC) , Pinnacle and Prowess Panther – CCC and Eclipse – PBC, Analytical Anisotropic Algorithm (AAA) and Acuros XB (AXB). Results For Elekta accelerators, all the calculation results show a deviation from the reference values lower than 3%. For Siemens and Varian accelerators, the resulting calculations for fields larger than 2×2 cm2 differ less than 4%. For 2×2 cm2 large fields formed by Siemens and Varian MLC, the differences between the calculated and measured output factors often exceed 5%, but still are below 10%. Conclusions The set of measured small field output factors provided by the RPC is a very good tool for QA of the treatment planning systems. A comparison of particular institution's data with the RPC data is very helpful in quality assurance of IMRT treatments. Such quality control should be performed before the IMRT is used in clinical practice. In Poland, the results of the audit were found very useful for the participants who should carefully investigate any detected discrepancies between the standard dataset and calculated values, with attention to the specific beam model.
        Speaker: Wojciech Bulski (The Maria Skłodowska Curie Memorial Cancer Centre and Institute of Oncology)
    • 10:30 AM
      Coffee break
    • Wednesday morning - Poster Presentations - Screen1
      Convener: Mr Oleg Belyakov (IAEA)
      • 116
        Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology
        Background of the study: In the last two decades, quantum dots nanomaterial have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way than crystals in macro scale, in many branches of human life. It was already showed that the negatively charged CdTe QDs (–21.63±0.91 mV), with good dispersity and fluorescence stability, were rapidly internalized via endocytosis by HUVECs. Methodology: Cadmium telluride quantum dots (CdTe QDs) were labeled by 68Ga radio nuclide for fast in vivo targeting and Coincidence imaging of tumors. Using instant thin layer chromatography method, the physicochemical properties of the Cadmium telluride quantum dots labeled by 68Ga NPs (68Ga@ CdTe QDs) were found high enough stable in organic phases, e.g. a human serum, to be reliably used in bioapplications. In vivo biodistribution of the 68Ga@ CdTe QDs nanoconposite was investigated in rats bearing fibro sarcoma tumor after various post injection periods of time. Results: The 68Ga NPs nanocomposite exhibited a rapid as well as high tumor uptake in a very short period of time (less than 10 min), resulted in an efficient tumor targeting/imaging. Meantime, the low lipophilicity of the 68Ga NPs caused to its fast excretion throughout the body by kidneys (as also confirmed by the urinary tract). Conclusion: Because of the short half-life of 68Ga radionuclide, the 68Ga@ CdTe QDs with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy.
        Speaker: Seyed Yousef Fazaeli hoseini Nezhad (AEOI)
      • 117
        The use of hypofractionated radiotherapy after breast conservative surgery or mastectomy in Albanian women with breast cancer
        Background: After the results of prospective randomized trials, hypofractionated external beam radiotherapy replaced the conventional dose fractionation in women with early stage breast cancer after breast-conserving surgery. However, its efficacy and toxicity after mastectomy is still under evaluation and not routinely used. The aim of this study was to demonstrate our experience in using hypofractionated radiotherapy in breast cancer women, and evaluation of acute toxicity profile. Methods and materials: Between May and October 2016, all 55 consecutive women with breast cancer referred to the Oncology Service of the University Hospital Center “Mother Theresa”, received hypofractionated 3D conformal radiotherapy (40.5Gy in 15 fractions) via a Linear Accelerator of 6 and 18 MV. 23 patients were irradiated to the whole breast with an additional boost dose of 10Gy in 5fractions at the tumor bed and 32 others to the chest wall. From all treated women, 33 of them were also irradiated concomitantly to the supraclavicular fossa. The dosimetric parameters and exposure to heart and lung were analyzed. Acute toxicity assessment was done based on RTOG toxicity criteria. Results: Hypofractionated radiotherapy was well tolerated by all patients, without interruptions. The mean age was 54 years (range 29-79 years) and 64% of women were postmenopausal. Early stage disease (Stage I and II) constituted 53%, while locally advanced 47%. The majority of patients (79%) had prior chemotherapy. The maximum radiotherapy dose received was on average 42.61Gy (range 41.84-43.38Gy). The mean lung dose was 7.39Gy and V20 was 16%. The mean V25 to the heart was 3.3% for left side and 0% for right side tumors. Acute toxicities were mostly skin toxicities of grade 1 in 73% of patients and grade 2 in 18% of them. Dysphagia and hematological toxicity grade 1 was seen in 2 and 3 patients respectively. No one had ≥ grade 3 toxicity. Conclusions: Hypofractionated external beam radiotherapy seems to be a feasible treatment for women with breast cancer not only after breast conserving surgery but also after mastectomy and treatment of supraclavicular fossa. It has shown low acute toxicities. However further follow-up is needed for better evaluation of patient’s outcome. Key words: Breast cancer, hypofractionation, radiotherapy, toxicity
        Speaker: Elvisa Kozma (Oncology Service, University Hospital Center Mother Theresa)
      • 118
        Adjuvant chemoradiotherapy (ACHR) for gastric cancer
        Aims & Objectives. Evaluation of ACHRT in improving local control and survival in patients with resectable gastric cancers. Materials & Methods. Between 2008-2015, 254 patients with gastric cancer (stage IB-IV), were prospectively randomly assigned to two groups. 122 patients underwent ACHRT combined with radical gastrectomy (ACHRT group) and 133 patients underwent radical gastrectomy without ACHRT (control group). From 4 to 6 weeks after radical surgery, the ACHRT was applied by using a hypofractionated radiotherapy, dose per fraction 4 Gy, 8 fractions, total dose 32 Gy in combination with daily oral administration of phtorafurum at 10-15 mg/kg followed by phthorafurum (tegafur) monochemotherapy (MCT) during 4.5 months. Results. During ACHRT, no grade IV side effects were recorded. In the course of administering the phtorafurum MCT, gastrointestinal toxicities (anorexia and nausea) of grade III (at CTCAE v.3 scale) were observed in 5 patients (4,5%). Discontinuation of treatment was observed in 29 patients (26.1%). Grade III hematological toxicities (neutropenia and thrombocytopenia) were registered in 4 patients (3.6%). None of the patients died due to the treatment administered. We noted survival improvement in the ACHRT-treated group. Overall 5-year survival (Kaplan-Meier) for the ACHRT group was 58.6±5.4%, that for the control group was 45.4±4.9 % [p=0.0466]. 5-year disease-free survival for ACHR group was 53.8±5.6%, that for the control group was 41.6±4.9 % [p=0.0228]. Loco-regional control was higher in 3.46 times in ACHRT group [p=0.002]. Distant metastases were occurred more often in 3.05 time in group without ACHRT [p=0.041]. Conclusions. ACHRT using dose hypofractionation regimen of radiotherapy can be an useful and effective treatment approach in certain cases of gastric cancer due to improving survival rate among gastric cancer patients. The treatment results in low toxicity and good tolerability.
        Speaker: Elena Slobina (Russian Scientific Center of RoentgenoRadiology)
      • 119
        A study on safety and efficacy of hypofractionated radiotherapy in post-operative breast cancer patients
        【Introduction】 FNCA (Forum for Nuclear Cooperation in Asia) is a Japan-led cooperation framework for peaceful use of nuclear technology in Asia. The cooperation consists of FNCA meetings and the project activities with the participation of Australia, Bangladesh, China, Indonesia, Kazakhstan, Korea, Malaysia, Mongolia, Philippines, Thailand and Vietnam. Radiation oncology project is one of ten projects, and conducting multicenter cooperative clinical trials on radiotherapy for common cancers in Asia have been carried out since 1994. The object of this joint group is to establish safe and effective, technically feasible and economically reasonable treatment in Asian countries. 【Objective】 We have been conducted clinical trial of hypofractionated radiotherapy for post-operative breast cancer since 2013. The aim of this protocol is to prove that hypofractionated whole breast irradiation (HF-WBI) in breast conserving thrapy (BCT) and hypofractionated post mastectomy regional radiothetapy (HF-PMRT) are as safe and as effective as conventionally fractionated radiotherapy and superior in terms of convenience. If the hypofractionated radiotherapy is equally useful for Asian patients, more patients will be able to receive radiotherapy in radiotherapy resource-poor countries. 【Methods】 The eligibility criteria for HF-WBI are patients who have undergone breast conserving surgery and have been histopathologically confirmed to have breast cancer, tumor size is either Tis, T1 or T2, undergone a lymph node dissection (including sentinel lymph node biopsy) and has been histopathologically confirmed to have 3 positive lymph nodes or less. The eligibility criteria for HF-PMRT are patients who have undergone mastectomy and have been histopathologically confirmed to have breast cancer, without positive margin, undergone a lymph node dissection (including sentinel lymph node biopsy) and has been histopathologically confirmed to have less than 8 positive lymph nodes. Patients with parasternal lympnode metastasia are excluded. Radiotherapy consisted of 2.7 Gy per fraction, 16 times, up to the total dose of 43.2 Gy to conserving breast on HF-WBI, or chest wall and supraclavicular fossa on HF-PMRT. The patients who have high grade factors, which are age less than 50, positive axillary lymph node metastasis, lymph vascular invasion, positive surgical margin are added 3 times boost irradiation to the tumor bed up to the total dose of 51.3 Gy. The accumulation number of cases was set as 200 cases in both arms. 【Results】From February 2013 to October 2016, 184 cases of HF-WBI and 131 cases of HF-PMRT were registered. In HF-WBI arm, the median age was 50 years old (range, 24–79). The clinical stage was 0 in 21 patients (11%), 1A in 100 (54%), 1B in 2 (1%), 2A in 42 (23%), and 2B in 19 (10%), respectively. One hundred five patients with high risk factors received boost radiotherapy to tumor bed. The median treatment duration was 26 days (range, 18–54). Acute dermatitis of grade 2 or more have been observed in 30 patients (17%) and grade 2 acute subcutaneous toxicity in 6 patients (3%). In regards to the late toxicity, grade 2 lung toxicity was observed in 2 patients, grade 2 skin toxicity in 1, grade 2 subcutaneous toxicity in 1, grade 1 heart toxicity in 5, and grade 2 heart toxicity in 2. One loco-regional recurrence, 2 distant metastases and 1 breast cancer death have been observed. In HF-PMRT arm, the median age was 48 years old (range, 24–74). The clinical stage was 2A in 50 patients (38%), 2B in 50 (38%), 3A in 27 (21%), 3B in 3 (2%), and 3C in 1 (1%), respectively. The median treatment duration was 21 days (range, 19–49). Acute dermatitis of grade 2 or more have been observed in 6 patients (5%) and grade 2 acute subcutaneous toxicity has been observed in one patient (1%). Acute grade 1 heart toxicity has been observed in 15 patients (11%) and late grade 1 heart toxicity in 6 patients (5%). Three loco-regional recurrence, 7 distant metastases and 3 breast cancer deaths have been observed. 【Conclusion】In the intermediate analysis, HF-WBI and HF-PMRT have almost the same effectiveness and safety as conventional fractionation. Additional registration and longer follow up must be needed to obtain final results.
        Speaker: Kumiko Karasawa (Tokyo Women's Medical University)
    • Wednesday morning - Poster Presentations - Screen2
      Convener: Mr Oleg Belyakov (IAEA)
      • 120
        Use of volumetric arc therapy for nodal boosting in cervical cancer radiotherapy.
        Background.Cervical cancer is the second most common malignancy affecting females in Azerbaijan and one of the main mortality causesin the female population in developing countries. In addition to its high morbidity rate in the developing world,cervical canceris usually diagnosed at late, locally advanced stages: 74% of new cases are IIB – IVA stage and this determines a higher risk of pelvic and para-aortic lymph node metastasis. Radiotherapy remains an integralcomponent of the standard treatment for locally advanced cervical cancer and a combination of megavoltage external beam radiotherapy (EBRT) and intracavitary brachytherapy (ICBT) with concurrent cisplatin-based chemotherapy is the accepted definitive modality of treatment. Brachytherapy allows increasing the dose delivered to the primary tumor while for metastatic lymph nodesit is possible only by external beam boostingup to a total dose of 60 Gy (by 2Gy fractionation equivalent dose, EQD2). But the main limitation for EBRT nodal boost is the proximity of surrounding normal tissues and organs like rectum, femoral heads, small and large intestine,, bladder and pelvic bones. Recent advances in radiotherapy techniques like volumetric modulated arc therapy (VMAT) make it possible to deliver higher radiation doses to targets while sparing organs at risk. On the other hand it is well known that prolongation of the overall treatment time could adversely affect radiation therapy results. Taking into account the above, we decided to use a VMAT-based integrated boost method for the treatment of node positive cervical cancer patients. Objective.The aim of this research was to document the treatment results of metastatic lymph node cervical cancer patients treated by VMAT-based integrated EBRT boost. Material and methods. We analyzed radiotherapy results of 52 patients treated in the Department of Radiotherapy of the National Center of Oncology, Baku, Azerbaijan from 2014 to 2016. Planning was done in automatic regimen and the dose distribution was improved (more conformal) if two dynamic arcs with 6 MV photon beams were used. The total number of fractions was 25. The fraction dose prescribed to the pelvis (primary tumor and regional zone up to the aortic bifurcation or L1-L2 interspace) was 2.0 Gy while the fraction dose prescribed to the metastatic lymph nodes was 2.3 Gy during the same treatment, thus reachinga total dose of 50 Gy and 59 Gy respectively (EQD2 by α/β = 10). From the first day of treatment patients received concurrent weekly cisplatin at the dose of 40 mg/m2 (max. 70 mg), 5 infusions. After 46 Gy of EBRT we started high dose rate (HDR)3D image guided brachytherapy which consisted of four weekly 7.0 Gy fractions to the high risk clinical target volume (HR-CTV). Results.Implementation of a VMAT-based integrated boost technique allowed reducing the total treatment time by one week in comparison with the sequential boost approach.Also, arc therapy having shorter irradiation time in comparison with traditional static field 3D conformal radiotherapy and IMRT procured an improved patient set up. We analyzed close results of the treatment which were assessed one month after the course was completed. Complete regression, partial regression and stabilization of the tumor occurred in 88.5% (n=46), 9.6% (n=5), and 1.9% (n=1) cases respectively. Conclusion: VMAT EBRT with integrated boost, HDR brachytherapy and concurrent cisplatin appears to be a safe and effective treatment modality for pelvic lymph node metastatic uterine cervical carcinoma providing high rate local tumor control and acceptable toxicity. It also could provide improved radiobiological conditions such asa shorter overall treatment time and higher fraction sizes. These may be especially important for radiotherapy of relatively hypoxic tumor cells in metastatic lymph nodes. But to reach final conclusions we need a longer follow up
        Speaker: Kamal Akbarov
      • 121
        Clinical implementation of intracranial stereotactic radiotherapy with non dedicated linear accelerator in a developing country: the cuban experience
        Purpose: To introduce stereotactic treatment performed with a general purpose LINAC for brain lesions management. Methods and Materials: Between April 2008 and august 2016, 35 patients underwent SRS (26) and SRT (9). The patients’ average age was 51 years old. The indications were: primary treatment in 21 cases (10-meningiomas; 8-schwanomas; 1-ependymoma; 1-pineal germinoma; 1-glomus) and 14 cases as post- whole brain radiotherapy ( 5-breast, 7-lung, 1-nasopharingeal and 1-colon brain metastases). Stereotactic treatment was delivered with 6MV general purpose LINAC. The techniques used were dynamic non-coplanar arcs with micro-multileaf collimator for 27 patients and non coplanar arcs using cones for other 4 patients. The treatment planning systems used were Elekta Ergo ++ and Elekta Monaco version 5.0. In the case of benign tumors, the average dose prescribed was 16 Gy (range, 13-17 Gy) for single fraction SRS and 8 Gy for 2 sessions of SRT. In the case of metastatic lesions, the average dose was 18 Gy (range, 16-19 Gy) for single fraction SRS and 7Gy for 3 sessions of SRT. In all cases the prescription selected curve was the 90% of the dose distribution. Plans were evaluated using: target coverage, conformity index (CI), homogeneity index (HI) doses in critical structures, in planning target volume (PTV). Results and Conclusions: Both treatments (SRS / SRT) were well tolerated. The assessed parameters were in agreement with the international reported levels, taking into account our technology and expertise. The multidisciplinary team, showed their capability of successfully handling these treatments.
        Speaker: Ivonne Chon Rivas (INOR)
      • 122
        Development of a BNCT facility based on axial Deuterium–Deuterium (D–D) neutron generator using MCNP code
        The Boron Neutron Capture Therapy (BNCT) is a promising method to treat malignant brain tumors. The basic principle of this technique is to irradiate the boron-containing tumor with epithermal neutrons. Optimization of the Beam Shaping Assembly (BSA) assembly for BNCT has been performed using the Monte Carlo N-Particle Transport Code (MCNP6) to shape the 2.45 MeV neutrons that are produced in the axial Deuterium-Deuterium (D-D) neutron generator developed at Adelphi Technology, Inc with a radio frequency (RF) driven ion source and nominal yield of about 1010 fast neutrons per second. Different materials and Beam Shaping Assemblies (BSA) are investigated and an optimized configuration is proposed. The feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-D neutron generators, TiF3 and Al2O3 as moderators, Pb as reflector, Ni as shield and Li-Poly as collimator to guide neutrons toward the patient position. Also a simulated Snyder head phantom was used to evaluate dose profiles due to the irradiation of designed beam. The neutron beam quality is defined by the standard free beam parameters, calculated averaging over the collimator aperture. The results are discussed and compared with the performances of other facilities.
        Speaker: kaouther BERGAOUI (National Center of Nuclear Sciences and Technologies)
      • 123
        Mathematical modeling and optimization of radiation therapy dose-time treatment scheme
        Optimization of radiation therapy treatment scheme using mathematical modeling is one of the topical problems in modern radiation oncology. For these purposes formalized description of dynamic processes in clinical radiobiology is used. Task of justification of radiotherapy dose fractionation schedules can be formulated in terms of the optimal control theory. For example, we fix a total radiation dose value D Gy and duration of radiation therapy treatment T. Then the optimization task can be formalized as follows: it is possible to reduce the number of survived cancer cells using radiotherapy dose fractionation schedule, provided that the total radiotherapy dose does not exceed D Gy and radiotherapy duration is Т days. Let consider the main biological assumptions used in mathematical models: 1. Cancer tumor consists both oxygenated and hypoxic cells. The volume of oxygenated fraction consisting of X cancer cells is Хoxygen/Х=exp(-b∙Х), b=const. 2. The fraction of oxygenated cancer cells consists of cells in different phases of the cell cycle - G1, S, G2, M phases. Hypoxic cells are in G0 phase. 3. Conventional survival equations are used for description of radiation effects on tumor cells at different stages of the cell cycle G1, S, G2, M, G0. Cells in G0 phase are more resistant to radiation therapy. 4. Radiotherapy induces arrest of proliferative activity of tumor cells, which is proportionate to the radiation dose delivered. With account of the above assumptions of mathematical models various scenarios of dose fractionation were examined. On figure 1 survival of cancer cells following delivery of equal-dose fractions (2 Gy/day) and nonuniform dose fractions (increasing fraction size up to 5 Gy/day) is presented. In both cases the total dose D is 50 Gy, the treatment period T is 5 weeks. It is seen that due to the use of dynamic fractionation of total radiation therapy dose the number of survived tumor cells can be reduced by a factor of 10 as compared to the original number (1010 cancer cells). So, modern methods of mathematical and computer modeling in clinical radiobiology are effective tools for optimization of radiation therapy dose-time. treatment scheme.
        Speaker: Aleksandr Meniailo (A. Tsyb Medical Radiological Research Centre - branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation)
      • 124
        Intensity modulated radiotherapy benefits comparing to conventional radiotherapy for locally recurrent nasopharyngeal carcinoma
        Purpuse : Locally recurrent nasopharyngeal carcinoma (NPC) can be salvaged by reirradiation with a substantial degree of radiation related complications. The aim of this study was to evaluate the dosimetric advantage of intensity modulated radiotherapy (IMRT) in treating locally recurrent NPC. Methods : Between January 2015 and September 2016, six patients with no metastatic locally recurrent NPC were re-irradiated with concomitant chemotherapy. The median prescrepted dose was 60 Gy with 2 Gy per fraction. Treatment planning of each patient was performed for tow techniques : Three dimensional Conformal radiotherapy (3D CRT) and Intensity modulated radiotherapy (IMRT). The minimum dose (Dmin), the maximuim dose (Dmax) and the volume that received 95% of the dose prescrepted (D95%) of the planning target volume (PTV) and doses to the organs at risk (Spinal cord and brainstem) were calculated and compared for the tow techniques. Results : All two techniques delivered adequate doses to the PTV. The average Dmin was 48Gy for the two techniques, the average Dmax was 67,5 Gy vs 64,2 Gy respectively for IMRT and 3D CRT (p=0,41) and D95% was 96%. Concerning the organs at risk, the Dmax for the brainstem was significantly higher for 3D CRT (22 Gy vs 14 Gy, p= 0,003). This finding were similar for the spinal cord (20Gy vs 7,8 Gy). But, the difference was not statically significant (p=0,12). Conclusion: Based on the dosimetric comparaison, IMRT was optimal by delivering a conformal and homogenous dose to the PTV with significant better sparing of critical organs than 3D CRT. In this regard, re-irradiation using IMRT may be a very attractive technique for locally recurrent NPC.
        Speaker: Hend Daoud (Radiotherapy department of University Habib Bourguiba Hospital)
      • 125
        An investigation of partial volumetric arc therapy versus 3D conformal radiation therapy for early stage larynx cancer
        Larynx cancer is the one of the most common head and neck malignancy and almost half of these malignancies present at an early stage (T1T2N0). This disease is includes several effective treatment modalities;radiation therapy, endoscopic resection,open partial laryngectomy. The goal of any therapy is cure with larynx preservation, high voicequality, and minimal morbidity. High dose radiation to the carotid arteries can lead to vascular disease. Using conventional techniques can cause carotid artery stenosis and increase the risk of ischemic stroke. The dose to the planning target volume (PTV) in all patients was 6300cGy in 225cGy per fraction.Target delineation of CTV to PTV margins as low as 0.3 cm have been utilized. The entire spinal cord, the bilateral carotid arteries were contoured as organs at risk (OAR). The plans were normalized such that the PTV and CTV D95 was equal to the prescription dose. 4 patients with partial volumetric arc therapy and 3 patient with 3D conformal therapy were compared. PVMAT plans were planned with 2 arcs between 110 and 250 degrees. D95 of the PVMAT and 3D plans were 6355, 6300, 6318, 6306cGy and 6302, 6303, 6337 cGy, respectively. The mean right carotid artery dose was 2331, 2642, 2323,2923cGy and 6230,6266,6329 cGy in the PWMAT, 3Dplans, respectively. The mean left carotid artery dose was 1878, 2657, 1883, 3088cGy and 6278,6316,6299 cGy in the PWMAT, 3Dplans, respectively. Dmax of spinal cord of the PVMAT and 3D plans were 1209, 2932, 2812, 2136cGy and 1083,3820, 780 cGy, respectively. PVMAT seems to have increased OAR sparing with nearly same spinal cord preserving and same tumor coverage. This will help to increase tumor control in head and neck tumors by allowing for dose escalation and better target coverage.
        Speaker: Nur KODALOGLU (Hacettepe University-Numune Research and Training Hospital)
    • Wednesday morning - Poster Presentations - Screen3
      Convener: Mr Oleg Belyakov (IAEA)
      • 126
        Tunable compact monochromatic X-ray synchrotron radiation source based on inverse compton scattering for advanced radiological applications
        Radiation protection of patients and physicians are the main concern of radiation protection program adopted in any radiological facility. The usage of conventional X-ray sources in radiological facilities is usually associated with exposure to wide spectrum of X-ray energies although only a narrow band of the X-ray spectrum is used in diagnostic/treatment process, while the remained spectrum is considered to be parasitic and non avoidable. In some radiological applications this parasitic portion contributes significantly to the total dose delivered to the patients as well as the physicians. Accordingly, developing and implementing new advanced diagnostic/therapeutic technology that use tunable mono-energetic (monochromatic) X-ray source without generating such parasitic portion of conventional X-ray sources will lead to significant decrease in the dose delivered to both patient and physician; this in turn will enhance the radiation protection program significantly. In that context, there were a plenty of research papers already proved the fascinating use of monochromatic X-ray synchrotron radiation in many radiological applications. Figure 1 represents an example of such outstanding applications of monochromatic X-ray radiation in early diagnostics of breast cancer; more details will be introduced in the full paper of this synopsis. However, high brightness monochromatic X-ray synchrotron radiation is traditionally obtainable exclusively in giant facilities like 3rd generation light source when ultra relativistic electron beam (GeV) passes through a periodic magnetic structure (undulator). This unluckily limits the dissemination of the radiological applications of X-ray synchrotron radiation within the synchrotron facilities only. In order to disseminate this technology worldwide, a novel and compact system should be developed in order to be hosted in ordinary hospitals. Many research efforts have been conducted during last decade to develop a compact system that offers the opportunity to produce high-brilliance X-ray synchrotron radiation with a laboratory-scale when a relativistic electron beam from linear accelerator (LINAC) collide with high power laser via Inverse Compton Scattering (ICS) interaction. Unfortunately, so far, no system has been produced in commercial scale due to some technological difficulties related mainly to the linear accelerator (LINAC) which is the main core of that system. In this contribution we propose a certain compact (≈ 1 m) traveling wave X-band (12 GHz) LINAC that can produces up to 50 MeV electrons suitable for ICS source. This X-band LINAC has been proposed in specific since a similar structure has been already designed and fabricated in cooperation with CERN, Paul Sherrer Institute (PSI) and Italian synchrotron facility ELETTRA; one of the authors has been involved in developing such LINAC. The CERN-PSI-ELETTRA structure is based on cutting edge technologies such as mode launcher and alignment monitors that overcomes the most known shortcomings associated with other versions of X-band LINACs; many unites are already fully functioning at the premises of aforementioned facilities without any significant technological problems; this nominates such X-band LINAC as a best solution for ICS source. Usually, the output electron beam parameters will be significantly affected by the operating conditions of LINACs such as the field gradient, initial & final beam energy, length of LINAC & its type, operating mode, shunt impedance, etc. Accordingly the output electron beam parameters will be significantly different form purpose to another. To prove the suitability of the proposed X-band LINAC to be used for ICS source, the LINAC resonance cavities have been simulated using SUPERFISH code and the output electromagnetic field mappings have been used to investigate the electron beam dynamics along the LINAC using ASTRA code. Finally, the monochromatic X-ray that is produced by collision between the electron beam with Table Top Terra Watt (T3W) laser has been simulated using CAIN code. The simulation results show that the resultant monochromatic X-ray is very convenient for many advanced radiological applications such as Dynamic Intra Venous Coronary Arterio Graphy, early diagnosis of breast cancers and Auger Cascade Radiotherapy. We conclude that, the CERN-PSI-ELETTRA X-band LINAC and similar LINACS proposed in this study is the best candidate for ISC source and eventually a quantum leap in achieving a stable and compact ISC source is at the reach of hands in very near future.
        Speaker: Mostafa ELASHMAWY (Nuclear and Radiological Regulatory Authority)
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        Novel hybrid pixel detector design for the use in continuous on-line dose monitoring in radiotherapy.
        The description of the design of a lower resolution hybrid silicon pixel detector, designed specifically for the purpose of continuous spatial on-line dose monitoring during the whole treatment.
        Speaker: Gordon Neue (UJP PRAHA a.s.)
        Slides source
      • 128
        Characterization of a Cobalt-60 radiotherapy unit upgrade: BEST Theratronics T780C to Equinox100
        Introduction: We have been investigating Cobalt-60 (Co60) based radiation treatment for some time through measurements on a Theratron 780C (T780C) Co60 teletherapy unit (Best Theratronics, Kanata, ON, Canada) installed at the Cancer Centre of Southeastern Ontario. Purpose built equipment was added to the unit to emulate serial tomotherapy dose delivery and enable imaging with electronic portal imaging devices. The research was complemented by Monte Carlo simulations. Results clearly indicated that modern radiation delivery is achievable using a Co60 source. In the past year our T780C unit has been upgraded by Best Theratronics to an Equinox External Beam Therapy System (Equinox100). This is the first full upgrade of an existing T780C unit into an advanced computerised Co60 unit (see Figure 1). The upgraded unit has an increased source-to-axis distance of 100 cm (previously 80 cm), new beam collimation and motion control, a motorized 60° wedge, and a new Avanza Patient Positioning Table (couch). The Equinox upgrade allows the unit to be equipped with a DICOM-RT compatible multi-leaf collimator (MLC), which is being incorporated into the unit. The MLC will enhance the unit’s three dimensional conformal radiotherapy capabilities and provide the potential for intensity modulated dose deliveries on the unit. At installation, the upgraded unit passed all acceptance tests specified by Best Theratronics for a new Equinox100 unit. In this paper we present the results of further commissioning tests performed to assess the upgraded unit’s readiness for clinical use. Methods: The commissioning of the upgraded Equinox100 unit closely followed the process and procedures used for clinical linear accelerators at our centre. Steps included testing of mechanical and radiation beam/dosimetric parameters of the system critical to accurate treatment delivery. Mechanical testing included evaluation of the accuracy of optical distance and field size indicators along with couch position and gantry, collimator, and couch angle readouts. Couch deflection was measured with a distributed load of 75 kg. Comparisons of gantry, collimator and couch mechanical and radiation isocentres were performed using EBT3 Gafchromic film (Ashland Specialty Ingredients, Bridgewater, NJ, USA). Radiochromic film was also used to evaluate the coincidence of radiation and light fields. Percent depth dose for different field sizes and in-plane and cross-plane dose profiles at multiple depths were measured using an ion chamber in a Blue Phantom2 water tank (IBA Dosimetry GmbH, Schwarzenbruck, Germany). Dose profiles were also recorded with the 60° wedge in place. Relative dose factors (RDF) were determined at depths of 0.5 cm and 5 cm. All measurements were repeated for the relevant range of square fields (3x3 cm2 to 40x40 cm2). Additional data is being acquired to commission the unit in the Eclipse external beam treatment planning system (Varian Medical Systems, Palo Alto, CA, USA). Results: Optical Distance Indicator (ODI) readings were in agreement with mechanical measurements within tolerances of 1mm at 80 cm and 100 cm and 4 mm at 120 cm. Field size readouts were found to be accurate to within 1 mm for all field sizes. Light and radiation fields were found to be coincident within 2 mm for 5x5, 10x10 and 20x20 cm2 fields. At all positions, couch, collimator and gantry angle readouts were found to be accurate within 0.5°. Couch positioning was accurate to within 1 mm over a range of ±20 cm from isocentre in all three directions. A distributed load of 75 kg produced a maximum couch deflection of 8 mm. Radiochromic film measurements showed radiation isocentre sizes of 0.23 mm, 0.44 mm and 0.05 mm for the gantry, collimator and couch systems, respectively. Radiation isocentre, indicated by starshot film measurements, to mechanical isocentre distances were measured as 0.56 mm, 0.70 mm and 0.19 mm for the gantry, collimator and couch systems, respectively. Measured percent depth dose curves showed good agreement with reference data published in the British Journal of Radiology Supplement 25. RDFs compared to the output at depth of maximum dose (0.5 cm) of a 10x10 cm2 field measured for the upgraded Equinox100 varied by less than 0.75% from the RDFs of the pre-upgrade T780C unit. Conclusions: All tests indicate that performance from the upgraded T780C unit was equivalent to that expected from a newly installed Equinox100 unit. In all mechanical testing the upgraded Equinox100 met or exceeded the manufacturer’s acceptance testing tolerances. Dosimetric measurement results show that the beam is identical to Co60 units referenced in medical physics literature as well as the pre-upgrade T780C unit. This confirms the expected advantage of Co60 radiation therapy: units have consistent well established radiation delivery properties. Current work is underway to extend measurements to MLC defined radiation beams on the Equinox100, incorporating and validating the upgraded Equinox100 in our Monte Carlo modelling, and evaluating various commercial treatment planning systems.
        Speaker: Chandra Joshi (Cancer Centre of Southeastern Ontario)
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        Standardisation of treatment planning in frameless stereotactic radiosurgery and radiotherapy using volumetric modulated arc therapy (VMAT) beams
        Aim: To standardise stereotactic treatment planning for new cases through compiling and categorization of a large number of treatment plans for a variety of clinical scenarios and automating plan selection from this plan library based on patient specific parameters. Materials and methods: One hundred and seventeen patients who were treated by stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) in our clinic for their intracranial lesions between March 2013 and December 2015 were included in this study. In all, 120 VMAT-based stereotactic plans (SRS/SRT) were generated for these patients and were pooled together to create a library of plans. All the plans were done in MONACO (v 5.00.04) treatment planning system (TPS) using the Monte Carlo dose calculation engine. These plans were categorized on the basis of eight different parameters: (i) Number of PTVs (ii) Prescription dose (iii) laterality (left /right) (iv) tumour volume (v) Whether PTV dose coverage was challenged by presence of organ at risk (OAR) or not, (vi) shortest distance between OAR and PTV (vii) centre to centre distance between OARs and PTV and (viii) lateral dimension of external contour (brain). Subsequently, for every new patient, the most appropriate plan was chosen from this library of plans on the basis of above categorisation using an ensemble mapping auto-select technique. The programming was done with a macro-enabled Excel worksheet. The auto-selected treatment plan (ATP) from the library of plans was ‘copied’ to the new patient keeping all beam and optimization parameters unchanged and placing the isocenter at the center of the new patient’s PTV. Optimization and dose calculation was carried out in the MONACO TPS with no or very minimal changes in the optimization constraints and arc lengths. In addition to this ATP, another individualized treatment plan (ITP) was generated by an experienced medical physicist independently without taking into consideration the library plan. The two sets of plans were compared. The ATP and the IP were evaluated for PTV receiving 98% prescription dose (V98%), Paddick conformity index (PCI) , dose spillage in terms of volumes receiving 50% and 20% of prescription dose (V50%, V20%) and OAR doses. Results: For 43.3% (52 out of 120) patients it was observed that dose coverage to PTV was not challenged by the presence of any OAR. Validation results for ensemble mapping technique showed that the Excel program could select an appropriate plan from the plan library for the new patient in question. Although the program could select the appropriate plan and ATP could be generated for the new patients, the independent plans were marginally better than the auto-select plans in PTV coverage and dose conformity. The mean PTV volume receiving 98% prescription dose (V98%) was 98.7±1.1% and 97.5±1.3% for the IP and auto-select plans respectively. Similarly the mean value for PTV’s conformity index was slightly better in ITP (0.712) as compared to that for auto-selected plans (0.693). However both PTV V98% and PCI were not statistically different between two sets. For the largest prescription dose group (12 Gy in 1#, 64 patients) brainstem 0.5 cc volume exhibited mean doses of 873.1±134.2 cGy and 854.5±122.4 cGy for ITP and ATP respectively. Mean 0.2 cc optic chiasm dose were 690.1±78.3 cGy and 734.0±67.8 cGy for ITP and ATP respectively. MU difference was very nominal with ITP showing a mean excess MU of 67.3 (3.7%) over ATP. ITP required on average 3.5 optimizations/dose calculation which ranged from 3.5 to 5 hrs, where as ATP required not more than 1.5 to 2 hrs. Conclusion: ATP validation results indicated multidimensional ensemble mapping mechanism can pick up the appropriate plan from the library of plans accurately for new cases. ATP plans, even though marginally inferior in plan quality to the ITP, can fulfil all the required clinical conditions and dose constraints. ATP plans save considerable planning time and is not dependent on the treatment planner’s skills and expertise.
        Speaker: Tharmarnadar GANESH (Fortis Memorial Research Institute)
    • Wednesday morning - Poster Presentations - Screen4
      Convener: Mr Oleg Belyakov (IAEA)
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        Analysis of setup incertanties generated in 6D ExacTrac X-Ray system for patients in hypofractionated treatments of intracranial radiosurgery
        **Introduction** With the growing technology in radiotherapy, the complexity of treatment planning has been increasing and higher doses have been delivered to tumor, so it is necessary to assess the accuracy of patient setup in order to guarantee better compliance of tumor with greater protection of healthy tissues. To achieve this goal, image guided radiotherapy (IGRT) is mandatory role, especially for hipofrationated treatments, such as cranial radiosurgery. The ExacTrac X-Ray 6D BrainLAB is an IGRT system that uses an infrared (IR) system for pre-positioning, robotic table with six degrees of freedom and two orthogonal X-rays tubes for imaging. Using IGRT it is possible to reduce PTV margin to minimize dose delivered to normal tissue, but it is necessary to reduce setup uncertainties. These uncertainties can be separated into random and systematic errors. A systematic error may be understood as an average variation occurred during the treatment. A random error on the other hand, can be defined as the dispersion of systematic errors over time of treatment. The purpose of this study is to evaluate setup uncertainties for patients treated with radiosurgery intracranial hypofractionated using IGRT with ExacTrac. **Materials and Methods** *Exactrac System* Treatments localization based on the ExacTrac X-Ray 6D system includes two steps: a pre-positioning using IR and X-ray verification images. The IR component has two emissors of IR waves and two cameras installed on the ceiling to read the signal that is reflected by reflective beads distributed on the surface of the patient or on a localization box. Using this information an automatic setup can be easily determined by moving the table to coincide with the positioning marks determined by the CT image. The X-ray component consists of two orthogonal X-ray tubes installed on the floor and two panels on the ceiling. Two orthogonal X-rays images are obtained and compared with reference bone anatomy using automatic fusion to DRR images generated by exactrac software. The result of comparison gives the setup uncertainty in six degrees of freedom: three translational and three rotational. *Treatment* We evaluated 36 patients treated with intracranial hypofractionated radiosurgery from August 2015 to October 2016 in a Varian linear accelerator 6EX. The dose prescribed was 25-30 Gy in 5 fractions for 30 patients and 12-18 Gy single fraction for 6 patients. Immobilization of the patient was taken with BrainLab masks. This mask is comprised of three reinforcement strips of thermoplastic material arranged in the forehead, nose and chin. The treatment isocenter were pre-localized using the localization box and correct the positioning after taken X-Ray images. The first image deviations were not considered in the analysis. During the treatment, in each angle of table it was taken images and the variations calculated were corrected if it was outside limits acceptable range (0,7 mm for translation and 1º for rotation). The corrections were recorded for future analyses. Deviations generated in the translational coordinates (vertical, lateral and longitudinal) and rotational (roll, pitch and yaw) were analyzed and expressed in terms of mean values and their standard deviations. The random error distribution (RMS(σi)),variation in systematic error (Σ(μi)) and overall distribution of setup corrections (Σoverall) were determined as presented by Infusino, Erminia et al. **Results** We had a total of 656 X-Ray images. All these measurements were used to calculate the errors presented on Table 1. The systematic error in the lateral, longitudinal and vertical was very small, 0.14, 0.26 and 0.15 mm respectively. Random component was a little larger, ranging from 0.3 to 0.6 mm, probably because small internal movements of the brain, fixation power of the mask, inaccuracy of the fusion algorithm of the Exactrac, inclusion or exclusion of certain anatomic features, inter-observer variation in the interpretation of daily images. The maximum overall error was 0.6 mm. Additionally, the rotational correction were relatively small, ranging from 0.1 to 0.6º. The 3D vector could be calculated for the translational components, the value found was 0.9 mm. **Conclusions** The magnitude of the random, systematic and overall errors was quantified. The random component was larger than systematic one, opposite to that expected by the literature, showing as the Exactrac system is able to reduce the magnitude of systematic errors, so that the random error demands a little more attention, even because this kind of error is naturally difficult to minimize. But, even with larger random errors, the value of the 3D vector was sub millimeter (0.9 mm). This study emphasizes the importance of daily IGRT and the importance of monitoring setup error for treatments with high dose per fraction. [1]:
        Speaker: Camila Pessoa de Sales (Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo)
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        Stereotactic body radiation therapy in a public oncologic hospital in Brazil: a five years experience
        Introduction: The challenge of implementing a new technology in a developing country is huge in many aspects. Personnel training and updating are cornerstones in this process. Brazil has an incidence of about 596,000 new cases of cancer per year. In May 2008, the Instituto do Câncer do Estado de São Paulo (ICESP) Octavio Frias de Oliveira, a public institution linked to University of São Paulo, was established. The radiation oncology department started its’ activities in 2010. With 6 linear accelerators, 1 high dose-rate brachytherapy equipment and 1 computed tomography (CT) simulator, about 300 patients are treated per day using different techniques (conventional, 3D-conformal, intensity modulated radiation therapy, volumetric modulated arc therapy – VMAT, conventional and 3D image-guided brachytherapy). In 2011 the first case of stereotatic body radiation therapy (SBRT) was performed. The technique has potential benefits, as improvement of the quality of life of patients (by reducing the numbers of visits to the hospital and promoting better tumor control), and the possibility of treating a larger number of patients in busy departments likes ours (due to the potential more vacancy in the machines). On the other hand, requires high radiotherapy technology and appropriate personnel training. The clinical protocol, for such treatment, includes a CT scan with appropriate immobilization (eg thermoplastic mask, body fix), image fusion when indicated, delineation according to international protocols. Treatment planning is performed with Monaco® software, followed by quality assurance using an ionization chamber (0.125 cc) and a matrix detector (PTW 729®). Irradiation is delivered with Elekta Axesse® linear accelerator and daily cone beam CT. The purpose of this study is to analyze the evolution of the use of SBRT in the institution after the implementation of the technology and personnel training. Methodology: treatment records of the institution were reviewed and all SBRT treatments were selected. The numbers of procedures, the treated sites and respective treatment techniques were verified. Results: From September 2011 to September 2016, 106 treatments in 94 patients were performed (Figure1). The mean age of the patients was 68 years. Treatment sites were lung (60) followed by liver (22), bone metastases (15), pancreas (5), soft tissue sarcomas (2), and isolated lymphatic relapse (2). There are two clinical studies being developed: one for hepatocellular carcinoma and another one for soft tissue sarcoma. VMAT was used to treat 79 % of the cases, the number of fractions ranged from 1 to 8. The most used dose/fraction was 7.5 Gy (range: 5 – 20 Gy) with total doses ranging from 18 to 60 Gy. The number of procedures performed in the last two years (66) is higher than the sum of all other years (40). In 2016, a mean of at least 3 procedures/month was performed. This runs in parallel with the end of personnel training (2014) as well. Conclusions: after implementation of SBRT, the number of procedures increased exponentially during the observed period. The personnel training and learning curve may be related to these findings. There is still potential to grow in the field. This is a landmark for our institution that is offering and delivering high quality ablative treatments in the public context.
        Speaker: Julio Marcassa (Instituto do Cancer do Estado de Sao Paulo)
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        On the way to paperless – a multi-professional project in radiation therapy
        The installation of Mosaiq 2.62 (Elekta) in the Radiotherapy Department at IPOCFG, E.P.E. was preceded by a rigorous process of planning and configuration. A multi-professional working group was appointed to work out the complete workflow of a radiation treatment, trying to meet the usual followed procedures with an optimized sequence. Receptionists, secretaries, nurses, radiation oncologists, dosimetrists, medical physicists and radiation technologists have worked together for around three months prior to any software installation. The complete workflow of the patient through the treatment process in external radiation therapy (ERT) was discussed and structured, including all the forms and documents usually kept in paper support, for records. The process was led by a medical physicist. The purpose of this work is to present the result of this process which aimed at installing an Oncology Information System (OIS) that could regulate, control and register all the steps followed by the patient since his/her entrance in the RT Dept. towards his/her hospital discharge, including medical and nursing appointments, image acquisition procedures with positioning and immobilization requirements, structures delineation, treatment planning and optimization, treatment verifications and treatment delivery sessions, image review, nursing care procedures, medication prescription and clinical assessment of treatment outcome. The major ambition of this project was to make it paperless. RT Dept. staff includes 12 radiation oncologists, 3 residents, 25 RTTs, 10 clinical secretaries, 5 receptionists and more than 30 nurses. Six medical physicists and 5 dosimetrists, belonging to an independent Medical Physics Dept. give permanent support to the RT Dept. The major equipment integrates 2 Siemens Oncor linear accelerators, 1 Tomotherapy HD unit, 1 Simulix Evolution (Elekta) conventional simulator and 1 CT-simulator Siemens Sensation Open. A MR unit belonging to the Radiology Dept. is connected via PACS. The brachytherapy (BT) sector has one Flexitron (Elekta) afterloader for breast, gynae and prostate HDR implants. Also LDR prostate seed implants are performed with Prolink Bard system. Overall around 1500 patients are treated per year. The previous use of Lantis R&V system has facilitated the first approach to Mosaiq. The database conversion from Lantis to Mosaiq was done with no major problems. Mosaiq 2.62 installation required the upgrade of Syngo RT Therapist platforms of the Oncor linacs. The tools available in Mosaiq 2.62 made it possible to structure and configure the external radiotherapy (ERT) sequence for the first implementation phase of the Mosaiq project. IQ Scripts engine enables the use of logical building blocks to define patient pathways and clinical protocols according to the department clinical practice and the structured workflow. For ERT, the patient pathway included 76 Quality Check Lists (QCL) which correspond to the same number of task descriptions – e.g. booking of a clinical appointment, perform some nursing assessments, delineate structures, etc. Through IQ scripts these 76 tasks have been grouped by automation in 14 building blocks where one initial task triggers off for the intended staff or location a sequential list of tasks including the automated generation of the needed documents like dose prescription form or positioning and immobilization form. The sequential completion of each task drives the following steps of the process. At the end, the RT patient chart contains all the relevant information and approved documentation concerning his/her complete pathway through the RT Dept. Patient related documents can be either imported (like treatment planning documents, independent MU calculation or other patient specific QA documentation) or automatically generated and presented to the user for filling in (like dose prescription form, immobilization and positioning form, or the technical reception form through which the RTT welcomes the patient and registers some preference for daily treatment hours, for instance). The first type of documents is eScan whereas the second is eScribe. The latter requires Word configuration and may include merging fields to be automatically filled in upon, for instance, completing assessments in earlier steps in the workflow. ERT workflow configuration and testing in Mosaiq required one month full time of a dedicated medical physicist supported by Elekta applications specialist. An intensive training program was also organized for all professionals. Staff was divided in multi-professional groups and the configured ERT workflow was simulated with test patients. Connectivity to the general Hospital Information System (HIS) and the hospital electronic patient chart was assured by dedicated solutions that prevent task and registry duplication. This integration is a dynamic process that can evolve with the natural HIS development. The GoLive of paperless Mosaiq project took place on October 10, 2016. With less than one month of practice, it still requires a close daily monitoring. A daily 30 minutes briefing including a multi-professional team is a fundamental pillar of the successful implementation of such an ambitious project. Brachytherapy and Radiosurgery patient pathways have already been configured and will soon be tested and implemented.
        Speaker: Maria do Carmo LOPES (IPOCFG, E.P.E.)
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        Quality control, dosimetric measurement and clinical experience with intraoperative radiation therapy (IORT) - Intrabeam device
        INTRODUCTION: On February 2016 our department started to use an Intraoperative Radiation Therapy System (IORT) Intrabeam PRS 500 con XRS4. Carl Zeiss, with delivery energy of 50 Kv; as the same as other radiation therapy treatment requires position and safety during the treatment. In our service we developed a radio-protection manual and quality control program required by regulatory entities in Peru, independent measures were done with conventional techniques as ionizing chambers and radiocromic fields in solid water getting the absolute dose and isotropy for all applicators use in clinical practice. The INTRABEAM device 50 kV of X Rays have different kind of applicators as spherical shape, surface, flat and needle with different sizes from 1 to 6 cm, what allows us many different kind of medical uses as treatment in breast, skin, brain, pancreatic, liver, vertebral metastases. It is described key dosimetric parameters as relative and absolute dose and isotropy for each applicator, also the dose rate in different key points 1 and 2 meters from the applicator, to estimate the biological dose in Sv presents during treatment time and then established the radio protection plan. In Our Experience we have treated 22 cases where 68 % were breast, every treatment it is done the intrinsic control specified by the manufacturer what allow us measure the equipment stability. MATERIALS AND METHODS: All treatments were carried out with a IORT Device from the manufacturer Carl Zeiss Meditec AG, INTRABEAM model, with 50kV energy, measurements were made using ionization chambers PTW TN23342A, Electrometer PTW Unidos E model and dosimetric sheets EDR2, recommended manufacturer test are: ● Probe Centering: Tolerance 1mm ● Dynamic Deviation: Tolerance -0.5mm/0.5mm(1mm) ● PDA Control: IRM ±15.0% ● Output Control: ±10.0% Alternative procedures carried out in addition to those recommended by the manufacturer were: ● Isotropy (For circular devices). ● Dose in a reference point. ● Dose to 1mm of surface. This test were carried out using dosimetric sheets EDR2, ionization chambers mentioned. Solid water chamber RW3 phantom. Sheet Scanner ScanMarker 9800XL Plus Microtech. Regarding to quality guarantee we established a procedure program for radioprotection optimization such as where to place the leaded glass, sterile field X-Drape® D-110 use for getting rid of disperse radiation in 98%, and patient identification and also dose prescription. We evaluate beam stability that not exceed 1% been 10 times below established by the manufacturer. (Table N°1) and values in the time of mean IMR are 1.2% (Table N°2) at maximum 1.2% (Table N°2) at maximum that in comparison with the manufacturer gives is 12 times below of the tolerance. With regard to the clinical experience up to now so far we are treated 29 patients with good clinical results in slide A, B and C a magnetic resonance, Tumoral Bed post resection, and Intrabeam Spherical applicator that fits the cavity. CONCLUSIONS: 1. We confirmed that the use of sterile field attenuates in great percentage disperse dose. 2. Alternative Tests confirmed that the dose given to patients and prescription are within acceptance tolerance gaps. 3. As the correct the applicator is placed in contact to the surface to treat, the better the treatment will be, because 1mm of air or minimal inclination, the dose can vary up to 20%.
        Speaker: Roberto Carlos CHUMBIMUNI CONTRERAS (ONCOSALUD)
    • Wednesday morning - Poster Presentations - Screen5
      Convener: Mr Oleg Belyakov (IAEA)
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        Comparison of CT and PET-CT based gross tumor volume (GTV) and organs at risk (OAR) in IMRT of head and neck cancers: institutional experience
        Aim- To compare the gross tumor volume **(GTV)** and organ at risk **(OAR)** identified on CT to that obtained from fusion of PET and CT images i.e. hybrid PET-CT in IMRT planning for head and neck cancer. Material and Methods - Twenty five patients with primary carcinoma of the oropharynx and hypopharynx were included in this study after thorough history, physical examination, laboratory, histological and imaging testing. Patient immobilization was done by four clamp thermoplastic device. Separate CT and PET-CT simulation was done. Target volume (GTV) and Organs at risk (OAR) delineation was done by the same physician on separate CT and PET-CT images. A treatment margin was added to the CT GTV and PET-CT GTV separately to create the PTV. The planning dose prescribed for the study was 66Gy/33#@ 2Gy per fraction to the PTV containing the gross tumor volume. Different PTV pertaining to the macroscopic extension and microscopic extension (low dose PTV) were drawn. Two different IMRT plans were made for PET_CT and CT. Two different plans were made, one for the CT_PTV and other PET-CT_PTV and DVHs were generated for all critical normal structures. All the plans were generated with the standard dose prescriptions and the dose constraints of all the organs at risk were respected according to QUANTEC. Observations and Results – The following parameters were observed- - The effect of PET and CT image fusion on change in Staging, - Gross Tumor Volume - Dosimetric Comparisons of Organs At Risk between the CT only and PET-CT Plans. Hybid PET/CT imaging led to a change in staging in 7 out of 25 patients i.e. 28% as compared to CT alone in our study. Out of these 7 patients, Upstaging was seen in 5 patients and the remaining 2 were downstaged. In the rest of 18 patients i.e. 72% there was no change in the staging. The mean target volume of GTV as defined by CT alone, PET alone and PET/CT combined is 28.52 ± 15.08, 19.35 ±9.31 and 32.42 ± 15.92 cc. PET-GTV was smaller than CT-GTV in 20 out of 25 cases i.e. 80% and larger than CT-GTV in 5 out of 25 cases i.e. 20%. The mean CT-PTV AND PET-CT-PTV were found to be 252.17 ± 91.74 cc and that of pet-ct-ptv was 228.90 cc. The statistical tests between the CT-GTV & PET-CT-GTV and CT-PTV and PET-CT-PTV were found to be significant (p value 0.004 and 0.017 respectively ).The mean dose received by different organs at risk as a result of CT and PET-CT based planning was calculated and found to be significantly different for spinal cord, pharyngeal muscles and both cochlea ( ‘p’ value 0.057, 0.06 and 0.02 respectively).However, that of brainstem and bilateral parotid was found to be insignificant.( ‘p’ value – 0.34 and 0.58 ). CT is still considered the standard for treatment planning volumes and PET can be used for greater target delineation to avoid the geographical misses. But the larger gross tumour volumes would also put greater demands on complex planning to reduce the dose to organ at risk. Thus the added benefit of including the geographical misses can be impacted negatively by the close approximation of dose to the critical organs and this needs further prospective studies. With the advent of adaptive radiotherapy, using the fusion of PET and CT images during the course of radiotherapy is a promising approach to changing dose distributions and can be utilised for dose escalation strategies. Conclusion- 18F-FDG in oncology is a Gold standard as non-invaive functional imaging. In head and neck cancer, it has not been recommended for primary tumour as a lone modality, but only in conjunction with CT/MRI. Fusion of PET and CT images i.e. combined PET-CT can improve the GTV delineated on CT alone, highlight the unknown areas of disease and prevent geographical misses which possibly can over a long time, reduce the local recurrences and FDG- avid nodes can also be used for dose escalation. Based on our data as well as review of literature results, the incorporation of PET information may act as an adjuvant for radiotherapy planning and allow usage of highly conformal and biologically effective treatment.
        Speaker: Mridul Anand (Gujarat Cancer Research Institute)
      • 135
        Dosimetric Influence of translational and rotational motion correction using a robotic couch in the linear accelerator based stereotactic radio surgery and radiotherapy dose delivery
        Introduction: The linear accelerator based radiosurgery is initially started with invasive frame, like Lakshell frame and BRW frame. However in recent times improvement of setup imaging and other accessories like six dimensional motion enabled couch empower the community to move towards a frameless radiosurgery. Stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) deserves a very high degree of accuracy in reproducibility. While treatment, after placing the patient in couch due to the weight of the head, cranial side goes down due to fulcrum affect. In an invasive frame based case the head is attached to a couch mount with a three screws governing the rotational and translational motion able to provide all six dimensional motions to bring the head back in the appropriate position. However in a frameless SRS/SRT it is not possible. Therefore the couch six-dimensional motion is used for reproducing the patient position. The advantage of stereotactic localisation using an invasive frame can be completely or partially obtained by the cone beam imaging and six dimensional couch movements. In this study we would like to evaluate the dosimetric error in absence of couch motion. Materials and Method: 30 patients of either stereotactic radiotherapy or radiosurgery with 33 PTVs were planned in Monaco or iPlan Treatment planning system (TPS) and delivered in Elekta Axesse (Elekta, Stockholm, Sweden) linear accelerator equipped with uniform 4 mm width multileaf collimator (MLC). After placing the patient in the couch a cone-beam CT (CBCT) was performed yielding a set of positional correction values (called as primary correction values). Patient positional error translational (lateral, longitudinal and vertical) and rotational corrections (roll, pitch, yaw) obtain by CBCT was performed using the robotic couch to obtain the correct isocentre as well as alignment of the patient. Further another CBCT was acquired to verify the couch enable patient positional correction. Positional correction obtained in the second CBCT (called as residual correction) and either cannot be corrected further or having no dosimetric influence. Planner fluence was verified using 729/octavious Phantom with and without applying the primary and residual shifts in the couch and matched with the TPS obtained values. Further gamma index evaluation was done with the TPS generated planner dose (without shift) and measured planner dose with primary and residual corrections. Result Dose distribution was analysed using the gamma index used as sealing function. The mean difference between the {TPS-Measured with no couch shift} –{TPS-Measured with CBCT shift} and its standard deviation for a large range of γ (4.2-0.14) shows a very high variation of dose with a mean difference of 15.6% and maximum of 29.6% and minimum of 1.1%. The maximum, minimum and mean SD were 25.9% and 3.4% and 17.4% respectively. Mean 1%-1mm, 2%-2mm gamma passing when compared between TPS fluence and measurement obtained using a couch movement using primary correction values were 73.1±3.5% and 83.5±2.3% respectively. Same gamma criteria between TPS fluence and measurement obtained from applying the residual table correction yields 95.1±2.4% and 98.2±1.7% respectively. Discussion: Brainlab Elekta has come together for first time in our centre for offering the frameless stereotactic solution. However due to the specific design that brainlab base plate can only be fixed with the Elekta couch extension but not with the main couch a significant shift in the patient position was observed. As the couch extension is not firmly adhere with the main couch its acting as a lever of first kind; while putting the patient on the couch the cranial end goes down due to fulcrum effect. Sometime the movement in more than 1 cm. This movement of the cranial end may lead to a complete geometrical miss of the tumour. This problem appear for invasive frame stereotaxy as well and corrected using the roll, pitch, yaw rotation screws attached to the frame base. These rotational corrections attributed to the patient head weight and fulcrum effect is correctable only in terms of couch rotation and movement. As result shows the gamma passing with the primary table correction is significantly high and not suitable for therapy delivery. Nevertheless, positional error substantially decrease to an acceptable limits after applying the rotational and translational shifts to the table. Conclusion: Conclusively it can be stated that a imaging system having capability of 6D patient position matching and a couch system having capability of correcting the 6D motion should be used for the correction in frameless stereotactic therapy. Without the six dimensional motions enable robotic couch it’s not possible to correct the positional error properly and hence we strongly recommend the use of robotic couch during the frameless stereotactic radiotherapy and surgery.
        Speaker: Jayapriya Gupta (FMRI)
      • 136
        Enhancement of the biological effectiveness in the bragg peak: a nanodosimetric perspective
        In proton therapy, a constant relative biological effectiveness (RBE) of 1.1 is currently recommended and used in clinics. This is despite the fact that this quantity varies (for example with the depth of the proton beam) in a medium, which also causes a change in the biological beam range. Various authors have noted that it is worth considering these variations in treatment planning, especially for beams pointing towards or passing laterally adjacent to organs at risk. These variations are strongly dependent on the physical properties of the beam as well as on absorbed dose and the biological properties of the irradiated tissue. To study the physical properties of proton tracks, we examined biological effectiveness in terms of novel nanodosimetric quantities related to track structure based on the formation of ionisation clusters in target volumes, comparable in mass per unit area, to a DNA segment. The track structure of different ionising radiations can be characterised by nanodosimetric quantities derived through measurements and numerical simulations. In this study we present an investigation of the variation of nanodosimetric parameters with depth in the proton beam leading up to the Bragg peak region, which is an indication of the variation in biological effectiveness. Simulations are performed using the GEANT4-DNA extension toolkit that can simulate physics processes using models that can track step-by-step interactions of particles in liquid water down to the eV scale. The DNA target is modeled by a cylindrical volume of water with dimensions comparable to a DNA segment of 10 base pairs. These targets are placed at various positions in and around the track to map out the variation of nanodosimetric parameters. The results of this investigation demonstrate an ionisation cluster size distribution that shows an enhanced biological effectiveness at track ends (Bragg peak region). The enhancement of the biological effectiveness is observed in and off track axis. This result is in contrast to the clinically accepted use of a constant RBE value of 1.1 for protons.
        Speaker: Sonwabile Ngcezu (National Metrology Institute of South Africa & University of Witwatersrand)
      • 137
        Planning study of comparison of dose in target volumes and volumes of organs at risk in patients with high grade glioma. Intensity Modulated Radiotherapy versus Three-dimensional Conformal radiotherapy (3D-CRT).
        **Introduction:** Postoperative radiotherapy, together with surgery and temozolomide chemotherapy is one of the treatment modalities with curative intent in patients with high grade glioma (HGG, WHO Grade III). Survival of these patients is significantly longer compared with patients with WHO Grade IV tumors and long term CNS toxicity could be expected after radiotherapy treatment in this group of patients. Recent clinical data on long term survivals in group of high grade glioma patients is showing that decreasing dose in region of hippocampus could have positive impact on mental function in this group of patients. In our institution, standard treatment of patients with high grade glioma is 3D-CRT radiotherapy. **Methodology:** In our study we made retrospective planning study on 15 previously treated patients with HGG with 3D CRT. For this purpose we made treatment plan using same CT dataset with MR fusion and performed IMRT planning using inverse planning algorithm on Varian Eclipse Treatment Planning System (TPS). Comparison of 3D-CRT and IMRT plan data has been done. Dose volume analysis of following structures has been done: V57 Gy (volume receiving dose of 57 Gy and more), maximal dose in brain stem, maximal doses in optic lenses, maximal dose in eye bulbus, maximal dose in hippocampus, maximal dose in optic nerves, optic chiasm and cochlea. **Results:** Statistical analysis on patient data has been done and statistically significant difference in favor of IMRT Plans has been shown in V57 Gy volume (p=0.0461) and maximal dose in right cochlea (p=0,0431). Other critical structures has been shown decreased dose in organs of risk, but without any statistical significance. Maximal dose in right hippocampus has shown highest decrease but without statistical significance (p=0.0547) **Conclusion:** IMRT treatment of patients is feasible and decrease of dose is possible in some of the organs at risk. Selection of appropriate clinical cases is important to prove value of IMRT in treatment of patients with high grade glioma.
        Speaker: Igor Stojkovski (University Clinic of Radiotherapy and Oncology)
      • 138
        Dosimetric optimization of BATD-3D interstitial prostate treatments with 60Co and Multi-image technique
        INTRODUCTION: It is presented an efficient and quick method to dosimetric optimization using multi-imaging technique for intersticial prostate cancer HDR brachytherapy (BATD-3D) with 60Co Source- BEBIG. MATERIALS AND METHODS: Establish an optimization process for interstitial needle placement, target volume contour, Organs at risk contour, and treatment planning with the use of different image thechniques (MRI, CT and US) that optimize application time, planning time, and treatment total time. Also it is done dosimetric planification evaluation using different index such as COIN, Paddick Index (PI), conformity/gradient Index (CGI). RESULTS: In table 1 it is seen that dosimetrical values obtained for each organ at risk, achieving constraints for each case. In Table 2 it is also shown quality index to CTV coverage, observing a COINprom=0.738 and stablish the use of the Paddick PIprom=0.757 and accordance/gradient Index ICGprom=78.7%. This way we could see to parameters to quality control for a correct treatment placement. CONCLUSIONS: The correct use of Multi – Imaging optimize the different procedures in the application of interstitial HDR Prostate Brachytherapy (Fig. 1), as well using quality index such as (COIN, PI and ICG) in order to assure a correct treatment dosimetry. Organs at risk dosimetry needs to be in a narrow relation with CTV quality index, achieving the constraints for prostate volumetric treatments in our centre: • Rectum: D0.1cc≤80%, D1cc≤70% y D0.1cc≤60% • Bladder: D0.1cc<90%, D1cc≤60% y D0.1cc≤50% • Urethra: D0.1cc≤120%, D1cc≤70% y D0.1cc≤10%
        Speaker: Gustavo Sarria Bardales (ONCOSALUD - RED AUNA)
    • Session 11a - Personalized Medicine M3


      Learning objectives:
      1. To understand the concept and limits of personalized radiotherapy
      2. To learn the components of personalized radiotherapy

      Conveners: Dr Kirsten Hopkins (IAEA) , Dr Pedro Lara (Hospital Universitario Gran Canaria (Spain))
      • 139
        Personalized radiotherapy
        Speaker: Mr Soren Bentzen
      • 140
        Discussion, Q&A
    • Session 11b - Quality in Radiotherapy: various dimensions M1


      1. To review various quality dimensions in radiotherapy
      2. To discuss the role of quality audits in radiotherapy.

      Conveners: Dr Joanna Izewska (International Atomic Energy Agency) , Dr Nuria Jornet
      • 141
        The critical importance of high quality radiation therapy
        Speaker: Mr Kry Stephen F.
      • 142
        IAEA experiences with QUATRO audits
        Speaker: Dr Joanna Izewska (International Atomic Energy Agency)
      • 143
        Quality Assurance Team for Radiation Oncology (QUATRO): The National Center for Cancer Care & Research (NCCCR) experience
        **Introduction:** In 2009, the National Center for Cancer Care & Research (NCCCR)-Qatar underwent major upgrade of its facility and manpower. This upgrade included the commissioning of new equipment, the implementation of new techniques and modalities as well as recruiting new staff. In order to ensure that the quality of care provided meets international standards it was essential to solicit an independent external auditor. Due to the lack of national quality audit system in Qatar it has been decided that all the activities of the radiation oncology department will be audited by the group QUATRO. **Purpose:** This work describes our QUATRO experience as part of a comprehensive external audit of our radiation therapy facility. **Materials & Methods:** A detailed description of the tasks performed during both the preparation and execution phases is described. A team was first formed including leaders, technicians and administrative staff and a work plan that includes specific goals has been established. The first task was to familiarize our department with this type of audit and thus ensure a smooth running of the visit of the QUATRO group. This was done during one month prior to their visit through the study and the analysis of some documents sent by the group and through the completion of a questionnaire containing information about our department including the techniques used for treatment, patient information and staff specification and their qualifications. After this preparation step, the five-day visit of the team was organized and the main program of the visit was outlined. The visit started with a presentation addressed to the QUATRO group in which the history of our department, information about patients, treatment techniques and personnel was detailed. A presentation was then given by the QUATRO group underlying the goals of the audit procedure. In addition to observing the procedures applied in our department, a validation of our measurements was carried out by comparing them with those conducted by the group using their own equipment. At the end of this visit, a document was drafted by the group listing the outcome of the audit including the points on which improvements are recommended. **Results:** Although the QUATRO team stressed the fact that our department is capable to provide radiation therapy of very advanced technology and in consequence complies with the criteria of the IAEA for a center of competence, the auditing report of QUATRO group highlighted few areas of improvement. Since then, some of these recommendations have been implemented. The structure of Multi-discipline Teams (MDTs) has been reorganized and expanded. The site specific relevant MDTs are now attended by radiation oncologists to support patient accrual. In addition, further guidelines have been developed for target and Organs At Risk (OAR) definition and this process is now peer-reviewed. ICD codes have also been implemented. **Discussion:** The importance of this work lies in the fact that this is the first quality control audit in our department, carried out by an approved external organization. The classification of our department by the audit team as a center of competence for the next 5 years enabled us to validate the procedures practiced in our department and thus to strengthen our confidence level.
        Speaker: Adam Charles Shulman (Hamad Medical Corporation)
      • 144
        Quality Assurance Team for Radiation Oncology (QUATRO) audit to the Institute of Oncology and Radiology of Serbia: example of good impact on the development of radiotherapy in the institution
        Institute of Oncology and Radiology of Serbia (IORS) is the largest oncology institution in Serbia, dealing with cancer prevention, health care and treatment of malignant disease. Also IORS serves as a teaching base for Faculty of Medicine. Due to external and internal problems in Serbia in the last decade of the twentieth century, the problems and difficulties have been accumulated in field of radiotherapy. We were partially aware of our drawbacks so we requested a QUATRO audit from the IAEA. The main goal was to get an objective evaluation of the current situation and facilities, and to get guidelines for improvement of our radiotherapy department according to IAEA/ ESTRO established standards. The QUATRO audit was approved and conducted in March 2006 (13-17th) by an IAEA audit team. Auditors had full disclosure to all documents, facilities and protocols. All our staff members were very cooperative, active and answered to all given questions and requests from the auditors. IAEA Audit team report was completely objective and according to our situation in Radiotherapy Department. It revealed a significant amount of shortcomings in our protocols, QA/ QC procedures and guidelines. Moreover, auditors had many negative comments on our equipment and the lack of some essential radiotherapy devices and staff. After the IAEA mission we made some steps forward in order to improve the technology infrastructure in IORS and to adjust the clinical practice according to the established standards and suggested policy by the IAEA. We arranged many meetings with Government authorities in the attempt to acquire more funding. That resulted in the purchase of new crucial equipment suggested in the IAEA report: a CT simulator, Ro simulator, 3 new LINACs, dosimetry, QA and mould room equipment. On our part we made new written protocols and procedures; redesigned treatment sheets; continued to create institutional RT protocols; started implementing 3DCRT in most localizations; employed more RTT, physicists and physicians; devised a quality management system; defined the new educational programme for RT technicians according to ESTRO curriculum and started a postgraduate study in radiation oncology. We also planned to start a postgraduate study for medical physicist. We requested a follow-up audit to asses our development. The follow-up audit was approved and conducted from 7-9 December 2009 by the same audit team as in the first visit. The QUATRO team observed positive developments in our department. Substantial improvement in developing the infrastructure, logistics, and equipment upgrades had been achieved. Moreover, the audit team observed outstanding performance in some treatment units and concluded that our equipment is up-to-date. The overall impression of the follow-up visit was that IORS has been able to implement the recommendations of the lst QUATRO audit for significant improvement of both in technology and practice. The audit team concluded that with similar compliance to the recommendations of the follow up audit, there is a good chance to develop the department further with the goal of achieving the level of practice that fulfils the requirements of a center of competence. We are still working hard to further improve the situation in the Radiotherapy department of IORS and still use the QUATRO report recommendations as guidelines to achieve our goals to become a highly professional and effective service of evidence-based radiotherapy which follows the IAEA, ICRU and ESTRO criteria.
        Speaker: Suzana Stojanovic-Rundic (Department of Radiotherapy, Institute for Oncology and Radiology of Serbia; Faculty of Medicine University of Belgrade)
      • 145
        Moving a large and complex radiotherapy department: a medical physics perspective
        Introduction: On June 23, 2016, Peter MacCallum Cancer Centre in Australia moved to a new site in Melbourne close to Melbourne University and a large teaching hospital. The new centre opened on 27 June with four new (Varian Truebeam) and two relocated linear accelerators (21iX, Truebeam STX) in addition to a full suite of brachytherapy and special services such as total body irradiation. Seventy patients were part way through treatment at transition. We describe the project planning stages and the lessons learned from the project of moving a large radiotherapy department over a single weekend. Of particular interest are the role of medical physicists and the quality assurance measures put in place to ensure the safe transition. Methods: Preparations for the move commenced several years before the actual move; however, medical physicists only became involved intensively about 18 months prior with focus on radiation safety and commissioning. Fortnightly and in the last three months weekly meetings were held by a senior multidisciplinary steering group to review progress against the transition plan. Additional resources were obtained for medical physics as two temporary positions for 12 months and new equipment including a scanning water phantom. All new machines were commissioned or re-commissioned following national and international guidelines and independently checked by the Australian Clinical Dosimetry Service (ACDS). Of the transfer patients, sixty had treatment plans created using Varian Eclipse (mostly IMRT) and ten ELEKTA Xio. About the same number of new patients started treatment in the first two weeks of operation including 10MV, FFF beams and VMAT as new treatment modalities. All plans were checked using Mobius M3D plan check software and verified by analysing the MLC delivery files using Mobius FX. Additional patient specific QA measurements were carried out for all transferred IMRT patients using physical measurements (ArcCheck diode array). Results: While activities such as acceptance testing and commissioning were well predicted the implications of moving a complete radiotherapy service over one weekend created significant unexpected workload in particular in the weeks after the move. The use of new equipment and the introduction of new features required training and creation of documentation ‘on the fly’. The need to treat patients sequentially on more than one campus created additional patient specific QA requirements and the demand for new services increased faster than anticipated. Areas that were found to be under-resourced were radiation safety and IT support. A particularly interesting process was the development of a security plan for high consequence sources (HDR brachytherapy) as part of a heightened public awareness of the risk of nuclear terrorism. Similarly, the new IT infrastructure had not adequately accounted for the complexity and criticality of moving multiple planning systems and a radiotherapy information system (ELEKTA Mosaiq) while maintaining continuity of operation not just for the main site but also four satellite centres. Full or partial patient specific QA results over the transition time were analysed for 147 IMRT and VMAT patients. Mobius provided an efficient process for plan review (M3D) and verification of treatment delivery (MFX) based on independent beam data and incorporates patient specific heterogeneities. There was good correlation between M3D and MFX results verifying accurate MLC movements. The ArcCheck physical measurements, particularly the ion chamber in the centre provide an additional layer of confidence in the actual delivery even if their passing rates of a 3mm/3% gamma criterion did not correlate with the same criteria for the same plan in Mobius. The workload particularly for senior physicists familiar with the local procedures increased significantly due to moving over a single weekend. As some complex services (total body irradiation, stereotactic procedures and intraoperative radiotherapy) had been partially restricted prior to the move, demand for these physics intensive services built up very quickly. The time required for senior staff not only to ensure safe introduction of new services but to prepare adequate documentation in parallel was underestimated as was the need for training provision. The fact that the move occurred in the middle of winter, a time prone to people falling sick, did add to staff shortages. Finally, the near miss of a major accident caused significant strain in investigation, rectifying, reporting and documentation but highlighted the importance of a thorough quality assurance program. Conclusion: The successful move of a large and complex radiotherapy department required a lot of input from medical physicists. The move over a single weekend caused some interesting challenges for staff. In the transition planning process more attention should have been paid to the first three months after the transition when new procedures have to be implemented and new documentation developed. The availability of an independent dose calculation system proved to be an efficient process for the large number of plans to be reviewed and checked under considerable time pressure.
        Speaker: Tomas Kron (Peter MacCallum Cancer Centre)
      • 146
        IT safety requirements in the Radiation Therapy field: risks and solutions all over the process
        **Introduction** An impressive evolution of the Information Technology (IT) tools and systems since the invention of computers has radically modified Radiation Therapy. From standalone systems with limited and dedicated functionalities, to networks of all equipment through a common system, all these developments have resulted in a tremendous enlargement of the IT area, of the data transfer capacities and of the interactions between modalities (linacs, software, imaging devices). Maintaining this growth over the last half-century has been successful thanks to safety and security methodology. From aviation to nuclear power plants, from pharmaceutical process to surgery, from basic manual manufactures to complexes automatic industries, … everywhere checklists have been introduced to ensure an optimal level of process quality achievement. On the way to improve safety and efficiency in our Radiation Oncology department, we initiated an in-house software development in 2004. The need emerged from the sharp increase in complexity when IMRT was introduced as a routine treatment. The need was to keep a constant overview of the workflow as well as the detailed “to do lists” to be completed, at the right time and in the right order. A permanent flow of information is exchanged between systems, requiring specific quality control procedures of the accuracy of these transfers. **Material and methods** A web-based, open-source software has been developped, which is able to display the list of all the patients currently supported in the Radiation Oncology department. The system is called iTherapy Process (iTP, figure 1). The patients are distributed in various steps of the process (from the first consultation to the last radiotherapy session). Each step consists of a checklist relative to the process. Each step has also a colour code indicating which group of staff is in charge (for example planning in orange for physicists, or contouring in green for physicians). Whenever a step is completed, the person in charge validates it, and the name of the patient appears in the next step. This allows for immediate warning of the next person in charge that the file is ready to progress (from simulation to contouring for example). Some steps consist of checklist to verify the accuracy of digital data transfer. This is considered an efficient safety measure in a domain where risk is frequently underestimated. The different key points of the development story of this open source (AGPL Licence) software will be discussed, focusing on the pros and cons. The current challenges and our needs for the future will also be addressed. **Results** This software entered in production in 2005; it has been completely redesigned in 2012, and is called now iTherapy Process (iTP). Patient workflows are deeply detailed and frequently brought up-to-date by an ad-hoc department standing working party (the iTP committee). Next to the workflow management by checklists, several iTP steps contribute to automatize, standardize and centralise control tools (existing in the past as separate “Excel” sheets), like in-vivo dosimetry, brachytherapy sources management, patient delivery quality assurance, eNal protocol, communication book, incident reporting system, team planning, breakdown database and downtime calculation, … From the CT-scan room, where the Hounsfield Unit (HU) must be well known and calibrated, to the treatment delivery, our daily activities are supported by the digital world (IT) which has, in the end, an impact on the treatment delivery itself and his quality. The safety and quality of the treatments is a permanent goal but a perpetual challenge. We face today a high level of complex process. The checklists help to keep the teams on the right track. **Discussion and conclusions** Working on a complex process within a multi-disciplinary team calls for a very well organized “information transfer system”. Interaction between systems (TPS, OIS, Image viewer, linacs, …) usually works fine. But what is the safety level of those data transfers? How far can we trust the standard protocols (Dicom-RT, HL7, …), our storage areas, the modules used to transfer dosimetric information? Trustable data exchange protocols, automated and cross-check tools, standardizations, are currently lacking or are insufficient. iTP is an attempt to help the user to verify, after data transfer from a system to another one that the data have been transferred appropriately. But, in the long term, solutions to strengthen the big data world still need to be developed. Different area like aeronautic, chemistry, nuclear industry, banking or pharmaceuticals have developed (from the business as well as the legal point of view) a strong “safety and QA” oriented on the data transfer side. The medical world just starts to think about it. With all the technologies at our disposal, we must open our minds to new risks, to new challenges and also to new ways of working.
        Speaker: Maxime Coevoet (Cliniques universitaires St-Luc)
      • 147
        Cost-effective public procurements of equipment for radiotherapy: starting point of patient's safety
        Introduction Preparation of tender documentation for public procurement of expensive radiological equipment (e.g. linear accelerators, MRI and CT systems, etc.) is an important and highly demanding task. Involvement of senior professionals with broad knowledge, expertise and understanding of radiation therapy procedures and technology is essential for optimal outcome of the particular procurement. Hence, Radiation Oncologist, Medical Physics Experts (MPE) and Radiotherapy Technologist usually work as a team, which governs procedures related to such public tenders. Among them, MPE has pronounced role and responsibility for the preparation of technical specifications for the equipment as well as for the evaluation of offers. The competency of MPE has been underlined also in the latest ‘International Basic Safety Standards’ (IAEA, 2014) as well as within the European ‘Basic Safety Standards’ (EU Council Directive 2013/59/ EURATOM). In addition to technical specifications, it is worthwhile that tender documentation contains also a binding and cost-effective post-warranty maintenance contract sample, to assure, that the equipment performance remains at a high level throughout its life-period. Such approach could enhance the output of health service, shorten waiting lists and contribute to the overall well-being and safety of patients as well as to assure a higher quality of radiological procedures. The aim of this work was to find a simple analytical evaluation point system for a public tendering process when medical radiological equipment needed in radiotherapy is to be purchased. Such system should be fair and transparent on one hand and financially acceptable for hospitals on the other. Methodology It is assumed that apart from technical specifications, the price for the equipment and for the post-warranty maintenance contract are the most important parameters for the evaluation of offers for medical radiological equipment. Transparent tender procedures along with adequate management policy and system for the financial evaluation of bids is of paramount importance in a nowadays very fragile economic situation in many countries. Three main criteria were followed in our attempt to find adequate point system for the evaluation of bids: (i) it should simple, transparent and fair (ii) it should reflect hospitals’ needs (iii) it should be structured in such a way to eliminate the possibility of unreasonably high prices of the equipment or post-warranty maintenance. These considerations were analysed in order to find adequate formulas for the evaluation of final bids and to fulfil the aim of this work. Results (i) Our goal, to construct a system which is simple, transparent and fair was achieved in elaborating formulas which are linear without containing any complex analytical function. Such approach eliminates possibilities of misunderstanding or misinterpretations of the system. In addition, having in mind manufacturers of the equipment, transparency and fairness can be achieved by publishing complete evaluation system together with needed explanations already within the official public tender documentation. (ii) Hospital needs and available financial resources have to be identified and consequently, technical specifications for the equipment shall follow demands of modern radiation therapy and comply with financial restrictions. Hence, it is obvious, that management of the hospital and professional staff have to work hand in hand to use their financial assets in a cost-effective way, ultimately for the benefit of patients. It was assumed, that tender specifications are written in a way which allows, that at least two bidders (manufacturers) can fulfil all technical requests, considering also the conditions for the specific and general functionality of the equipment. (ii) Most challenging part of the evaluation point system was the question, how to avoid potentially unreasonably high prices of the equipment and post-warranty maintenance contracts. To overcome this problem, we have provided two sets of formulas. Within the first set, points are granted on the basis of normalising particular price to the average price of all bids. Within the second set of equations, prices for maintenance contracts are included in such a way to encourage bidders to offer financially acceptable prices. Taking into account both sets of formulas, it is virtually impossible that financially unfavourable bids would receive a high number of points. Formulas for the evaluation point system of bids are presented in Table 1. Conclusion Governing public procurements of expensive radiological equipment is demanding task for hospitals. On one hand, hospital management has to take care of financial sustainability of their services, on the other hand, a rapid development of technology in radiation oncology forces radiotherapy professionals to strive for best possible equipment and technical support for their patients in order to raise overall cancer cure rate. Within our study, simple formulas are presented, which could help hospitals to avoid high pricing and to purchase expensive equipment for the reasonable and competitive price. Additionally, such system provides a warranty that also the prices for post-warranty maintenance will be kept at reasonable and acceptable level.
        Speaker: Božidar Casar (Institute of Oncology Ljubljana)
      • 148
        Quality of radiotherapy services in post-soviet countries: an IAEA survey
        Background The fall of the “iron curtain” and dissolution of the Soviet Union represented a dramatic turning point for the countries involved. In the area of radiotherapy services, it is convenient to discuss the Soviet era as opposed to the post-Soviet/ modern era. The emphasis in the Soviet Union was on providing universally available free medical care, and this appears to have been achieved to a large extent. The post-Soviet countries had inherited the Soviet Semashko system of health care but, despite its achievements, many expressed discontent with what they saw as its poor quality, inefficiency and lack of responsiveness. There have been calls for change by national authorities, but they were less clear about how to address it, especially at a time of severe fiscal constraints and lack of personnel trained in concepts of modern medicine. Methods This Project was organized as a systematic gathering of information on the present status of radiotherapy practice in countries in Eastern Europe/Central Asia. The countries included in this study were: Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Republic of Moldova, Russian Federation, Tajikistan, Ukraine and Uzbekistan. Uzbekistan provided only general data on infrastructure, but did not participate in the survey. No reliable data on Turkmenistan could be obtained. Objectives of the Project were: [1]to assess the current radiotherapy infrastructure in a group of 12 post-Soviet countries, [2]to assess the quality of radiotherapy services in these countries through the use of validated quality indicators(QI), and [3]identify nonstandard radiotherapy practices. The survey collated information on the country’s radiotherapy infrastructure as well as the quality of practice in each individual RT centre. It was based on two sets of validated QIs of structure and process in radiotherapy: the Australasian Clinical Indicator Report 2004-2011, and the Italian set validated and published by Cionini et al.(R&O,2007). These sets were adapted to the practice in the region so that a few of the indicators were not used. Results The survey was sent to a total of 184 centres. 108 radiotherapy centres (59%) replied. The collection of data using the survey tool faced logistical obstacles in the Russian Federation. Of the total of 119 radiotherapy centres in the Russian Federation with available contact information, 80 acknowledged that they have received the survey, out of which 19 centres (16%) returned the requested data. Although the sample cannot be considered representative of this country, it gives an approximate idea of the realities and obstacles faced by Russian centres. From the quality of services viewpoint, the results showed that in many aspects of patient care and RT treatment chart management the indicators were up to international standards. However, some issues in individual countries were identified. Waiting time for RT was found acceptable. 90-100% of patients sign informed consent for treatment. Most cases are discussed among various disciplines; however, these are either consecutive consultations or organized ad-hoc (“consiliums”) for difficult cases, and not well-established multidisciplinary tumour boards. Mean 42.5% of RT courses are planned using CT and the proportion of curative/palliative cases is 2.7. Only in AZB and GEO most patients are treated using an MLC. The ratio of unplanned maintenance downtime/planned maintenance in days was 3.4 for Co-60 units and 5 for LINACs (benchmark should be ≤1). Except for Georgia, all other countries practice mostly 2D-radiotherapy planning and delivery, but some had a significant fraction of patients treated with 3D-CRT and a few with IMRT. The mean number of fractions for curative courses was 31, for palliative 14, and overall 23 fractions/RT course. At the time of the survey, two countries lacked brachytherapy systems. Many brachytherapy units using large Co-60 sources are still in use. Split-course RT is routinely used in 9/10 countries studied. This is done to avoid toxicity and is required by the local treatment protocols in H&N, cervix, lung and prostate cancers. The naming and task profile of RT professions is different than in western countries. Training in radiation oncology tends to be much shorter and in the majority of countries not well-structured. The specialty of medical physicist is not recognized in 9/10, and the specialty of RTT is not recognized in all countries. Appropriate training programmes for medical physicists and RTTs are lacking. Conclusions Strengths and weaknesses of radiotherapy services were identified. Most countries need modernization of the RT infrastructure coupled with adequate staffing numbers and education programmes. Some radiotherapy practices are not in line with what is considered modern practice in other regions. More attention is required to the areas of quality systems and safety. Quality systems should include regular independent audits as well as the use of radiation oncology-specific quality indicators over time.
        Speaker: Eduardo Rosenblatt (IAEA)
    • Session 11c - Toward a radical treatment of oligometasteses M3


      Learning objectives:
      1.Discuss the clinical evidence for treating oligometastases in lung
      2. Examine the challenges faced in the target definition and treatment of oligometastases

      Conveners: Dr Felipe Calvo, Dr Karen Christaki (IAEA) , Dr Kirsten Hopkins (IAEA)
      • 149
        Introduction to the treatment of Oligometastases
        Speaker: Mr Felipe Calvo
      • 150
        Imaging and treatment delivery from a Medical Physics perspective.
        Speaker: Mr M. Saiful Huq (UPMC CancerCenter)
      • 151
        Treatment delivery and clinical evidence for the treatment of oligometastases
        Speaker: Mr Gerard Hanna
      • 152
    • Session 12a - Contouring Workshop (Head and neck cancer) M3


      Learning objectives:
      1. To learn how to contour the GTV and CTV in head and neck cancer
      2. To learn how to contour OAR in head and neck cancer

      Convener: Dr Kenneth Hu
      • 153
        ASTRO on H&N cancer
        Speaker: Dr Kenneth Hu
    • Session 12b - Industry Lunch Symposium: Motion Management in External Beam Radiotherapy M1


      Learning objectives:
      1. To identfiy the latest technologies and strategies in motion management for radiotherapy

      Convener: Mr Brendan Healy (International Atomic Energy Agency)
      • 154
        Introductory remarks
        Speaker: Mr Brendan Healy (International Atomic Energy Agency)
      • 155
        Vendor presentation (Elekta)
      • 156
        Vendor presentation (Varian)
      • 157
        Vendor presentation (TBD)
      • 158
      • 159
        Concluding remarks
    • Session 12c - Industry Lunch Symposium: Image-Guided Brachytherapy M2


      Learning objectives:
      1. To understand the concept of image-guided brachytherapy
      2. To learn about the latest developments in image-guided brachytherapy

      Conveners: Mr Alfredo Polo (IAEA) , Mr Tomislav Bokulic (Dosimetry Laboratory, DMRP, NAHU, IAEA)
      • 160
        Introductory remarks
        Speaker: Mr Alfredo Polo (IAEA)
      • 161
      • 162
      • 163
      • 164
      • 165
        Concluding remarks
        Speaker: Mr Tomislav Bokulic (Dosimetry Laboratory, DMRP, NAHU, IAEA)
    • Session 13a - Access to high quality care: Challenges and possible solutions M1


      Learning objectives:
      1. To identify the problems to access high quality care
      2. To learn about the possible solutions to the problem of access

      Conveners: Dr Elena Fidarova (IAEA) , Dr Karen Christaki (IAEA) , Dr William Mackillop
      • 166
        Speaker: Dr William Mackillop
      • 167
        Speaker: Mr Kennedy Lishimpi
      • 168
      • 169
        Speaker: Dr Karen Christaki (IAEA)
      • 170
    • Session 13b - The role of international organizations and professional societies - Part 1 M3


      Learning objectives:
      1. To understand the role of professional societies in the global health agenda
      2. To identify opportunities for professional development

      Conveners: Mr Alfredo Polo (IAEA) , Dr Eduardo Zubizarreta (Section Head ARBR - NAHU - IAEA) , Takashi Nakano
      • 171
        Speaker: Ms Yolande Lievens
      • 172
        Speaker: Prof. Takashi Nakano (Department of Radiation Oncology, Gunma University Graduate School of Medicine)
      • 173
        Speaker: Ms Mary Evans-Gospodarowicz
      • 174
        Speaker: Ms Surbhi Grover
      • 175
        Speaker: Ms Soehartati Gondhowiardjo
      • 176
        Speaker: Mr Francis Chin
      • 177
        Speaker: Ms Lotfi Kochbati
      • 178
        Speaker: Mr Kenneth Hu
      • 179
        Speaker: Mr Hugo Marsiglia
      • 180
        Speaker: Mr Tomas Cobo
      • 181
    • Session 13c - Imaging for planning and treatment delivery in External Beam Radiotherapy - Part 1

      Learning objectives:
      1. To learn about the imaging modalities available for planning and treatment delivery

      Conveners: Mr Brendan Healy (International Atomic Energy Agency) , Prof. Dietmar Georg (Medical University of Vienna) , Dr Rajiv Prasad (IAEA)
      • 182
        Imaging for planning and treatment delivery in EBRT
        Speaker: Mr Tomas Kron
      • 183
        Questions and answers
    • 3:30 PM
      Coffee break
    • Wednesday afternoon - Poster Presentations - Screen1
      Convener: Mr Oleg Belyakov (IAEA)
      • 184
        Electro-hyperthermia as a radiosensitiser for locally advanced HIV positive and negative cervical cancer patients in South Africa
        INTRODUCTION: 5-year survival rates for cervical cancer can be as much as 50% lower in developing countries than in developed countries. The treatment of cervical cancer patients in State facilities in South Africa is complicated by the advanced stage of disease at presentation, limited resources in the facilities and high HIV incidence amongst patients. These challenges contribute to the poorer prognosis of State patients in South Africa. The high morbidity and mortality rates associated with cervical cancer increases the socio-economic burden of the disease on the community and the healthcare system. The investigation of a feasible radiosensitiser which can be used in conjunction with cisplatin to improve clinical outcomes for locally advanced cervical cancer is therefore warranted. The aim of this study is to determine the clinical and economic benefit of the addition modulated electro-hyperthermia to standard treatment protocols for locally advanced HIV positive and negative cervical cancer patients in State healthcare in South Africa. METHODS: This is an ongoing phase III randomised clinical trial with a target sample size of 236 participants. The trial is being conducted at the Charlotte Maxeke Johannesburg Academic Hospital in South Africa. Eligibility criteria include female participants between 18 and 70 years of age with FIGO stage IIB (initial distal parametrium involvement) to IIIB cervical cancer. HIV positive participants with a CD4 count above 200/µL and who have been on ARVs for at least 6 months are included. Participants with bilateral hydronephrosis or a creatinine clearance below 60 mL/min are excluded. Participants are being randomised into a “Hyperthermia” group and a “Control” group. Randomisation stratum: HIV status, age and stage of disease. Participants in both groups are treated with 50Gy of external beam radiation administered in 25 fractions, 3 doses of 8Gy HDR and up to 3 doses of cisplatin (80mg/m2). Participants in the Hyperthermia group are treated two local electro-hyperthermia (EHT) sessions per week, each lasting 55 minutes at 130W. EHT sessions are administered directly before external beam radiation using the EHY 2000 Plus capacitive coupling technique (device is supplied by Onotherm Gmbh). The measured outcomes are local disease control, quality of life, early and late toxicity and 2 year survival. Local disease control is assessed by Positron Emission Tomography (PET) scans and toxicity is graded according to the CTCAE version 4. EORTC and EuroQoL forms are used for the assessment of quality of life. RESULTS: Our preliminary results show a benefit in local disease control in the hyperthermia group without the addition of any unexpected early toxicities or adverse events and without a large increase in treatment costs. CONCLUSION: mEHT appears to be a safe an effective radiosensitiser which may be used in low resource settings to improve clinical outcomes.
        Speaker: Carrie Minnaar (University of the Witwatersrand)
      • 185
        Dose distribution characteristics and initial clinical results of two different dynamic tracking techniques for stereotactic body radiation therapy for solitary lung tumors
        Purpose / Objectives Recently, stereotactic body radiation therapy (SBRT) using dynamic tumor tracking (DTT) techniques has been increasingly used. DTT technique has been successful in reducing the size of the PTV and doses to the normal tissue. In our hospital, we have been performing two different DTT techniques, namely, robot arm-based DTT (RA-DTT; CyberKnife System) and gimbal-based DTT (G-DTT; Vero-4DRT System). We investigated the dose distribution differences between the two techniques and the initial results of SBRT for solitary lung tumors treated with these DTT techniques. Materials / Methods Between March 2013 and December 2015, 28 cases received DTT SBRT in our hospital. Among them 10 received with RA-DTT and the other 18 received with G-DTT. There were 15 primary lung tumors and 13 metastatic lung tumors. Twenty-seven tumors were located in the lower lobe. Their median age was 73 (range: 40-88). The male to female ratio was 20 to 8. The TNM stages for primary lung cancers were T1a in 6, T1b in 6 and T2a in 3. Histologically, there were 6 adenocarcinomas, 4 Squamous, 2 NSCLC, and 3 histologically unknown tumors. As for the primary site of metastatic lung cancers, there were 4 H&N, 3 esophagus, 2 colon cancers, etc. Regarding the reasons for declining surgery, there were metastatic tumors in 13, poor respiratory function in 8, old age in 6, refusal of surgery in 3, etc. CTV ranged from 1.2 ml to 32.5ml (average 12.9+/-11.7ml). Average CTV of RA-DTT was 10.6+/-7.9ml and that of G-DTT was 14.1+/-13.4ml (p=0.4). Average total normal lung volume (TNLV) was 2654+/-714ml. Average TNLV of RA-DTT was 2882+/-865ml and that of G-DTT was 2489+/-565ml (p=0.22). Average respiratory tumor movement was 16.9 +/- 6.4 mm (range: 6.7 ~ 31.2 mm). Fractionation regimen was 50Gy/4fr/1wk with the prescription point of D95 of PTV. Eighty to 100 beams were used for RA-DTT SBRT and 7 to 8 beams were used for G-DTT. Median follow-up period was 21.6 months (range: 2.6 to 37.7 months). Results Regarding dose distributions, average of maximum tumor dose was higher in RA-DTT (66.5+/-4.7 Gy vs. 59.1+/-2.9 Gy p<0.0001). Lung V20 was smaller in RA-DTT (4.9+/-1.6% vs. 8.0+/-4.9%; p<0.025). Lung V5 was similar in both techniques (25.3+/-6.9% vs.21.7+/-11.7%). Thus, the ratio V5/V20 was significantly smaller in G-DTT (5.36+/-1.65 vs. 3.00+/-0.90; p<0.0006). Overall local control rate at 2 year (LCR2) was 96.3%. LCR2 was 100% for primary lung cancers, and 91.7% for metastatic lung cancers. Regarding overall survival rate at 2years, it was 87.5% for primary lung cancers and 75% for metastatic lung cancers. As for toxicities, 2 grade 3 radiation pneumonitis have been occurred. One of them was primary lung cancer and the other was metastatic. Lung V20 value of both cases was greater than 15%. Conclusions By dose distribution intercomparison, with the same D95 prescription, RA-DTT gives higher maximum tumor dose. The ratio of lung V5/V20 is higher in RA-DTT. Although our clinical results are preliminary, DTT SBRT for solitary moving lung tumors might be promising with high local control rate and acceptable toxicity. However, higher lung V20 value (> 15%) might cause severe radiation pneumonitis even if this technique has been reported to decrease V20 values significantly compared with static SBRT.
        Speaker: Katsuyuki Karasawa (Dept. of Radiology, Tokyo Metro. Cancer and Infectious Diseases Ctr. Komagome Hospital)
      • 186
        MRTDosimetry - Metrology for clinical implementation of dosimetry in molecular radiotherapy
        In the last few years there has been an increase in Europe in the development and use of radiopharmaceuticals for treating cancer as well as an increase in the number of molecular radiotherapy (MRT) clinical trials that are expected to start in the near future. Currently, MRT provides a valuable treatment modality to around 50 000 to 100 000 cancer patients per year in Europe, including patients whose cancer responds poorly to all other types of treatment (e.g. neuroendocrine tumours). A similar number of treatments are estimated to be given for non-cancer diseases such as hyperthyroidism and joint effusions. However, in spite of the growing acceptance that an accurate knowledge of the radiation absorbed dose to critical tissues would provide a more effective targeted use of MRT, most patient treatments still follow the historical practice of administering a nominal activity of the radiopharmaceutical with a standard activity determined on the basis of Phase I or I/II clinical trials in order to find the activity level that causes serious normal tissue damage to less than an acceptable fraction of the clinical trial population (typically 5 %). The EC Directive 2013/59/EURATOM, Article 56 states that “For all medical exposure of patients for radiotherapeutic purposes, exposures of target volumes shall be individually planned and their delivery appropriately verified taking into account that doses to non-target volumes and tissues shall be as low as reasonably achievable and consistent with the intended radiotherapeutic purpose of the exposure.” The main objective of the European Metrology Programme for Innovation and Research (EMPIR) project MRTDosimetry is to provide metrology for clinical implementation of absorbed dose calculations in Molecular Radiotherapy (MRT). The focus of this project is on clinical implementation and is strongly directed by the involvement of leading scientists at MRT clinics across Europe while building on metrology expertise and involving stakeholders. This will be achieved by • determining branching ratios and emission probabilities for 90Y and 166Ho in order to enable improved quantitative imaging (QI) accuracy and dose estimation for these radionuclides, and to exploit new technologies in order to develop a suitable transfer instrument optimised for accuracy of measurements of the activity of MRT agents in clinics and radiopharmaceutical companies • developing 3D printing methods in order to generate a range of quasi-realistic anthropomorphic phantoms containing compartments fillable with known activities of radioactive liquid or standardised sealed radioactive test sources, having a range of geometrical complexity for validation of multimodal QI or absorbed dose measurement, and estimation of the uncertainties of measurement • generating multimodal images either from SPECT or PET-CT phantom measurements or Monte Carlo (MC) simulations to provide material for an open-access database of reference images to be used as reference data for commissioning and Quality Control (QC) of QI using SPECT or PET-CT • improving the accuracy and metrological traceability in the calculation of dose from time-sequences of QI measurements • determining uncertainties in relation to the full MRT dose measurement chain from a primary standard to a range of commercial and non-commercial dosimetry calculation platforms • facilitating the take up by healthcare professionals (clinical centres) and industry (scanner manufacturers and software developers) of the technology and measurement infrastructure developed by the project. MRT dosimetry, as currently performed, has no traceability to primary standards of absorbed dose. Therefore there is an urgent need to achieve traceability and to validate the calculation methods used for dose. Further to this, and central to any recommendations for dosimetry methods, is knowledge of the overall uncertainty associated with any particular method. Hence, the uncertainties in relation to the full MRT dose measurement chain (i.e. from a primary standard to a dosimetry calculation platform) also need to be determined. The MRT community has an urgent need for dosimetry calibration standards, validation methods, and clear guidance on how to implement MRT dosimetry in every European clinic offering MRT. Without this, it will not be possible to comply with EC Directive 2013/59/EURATOM, Article 56, which states that individual dose planning for radiotherapy patients (including MRT) must be enforced in legislation by EU member states by 6 February 2018. The current, main source of uncertainty in MRT dosimetry is in taking the step from dose measurements on simple reference geometries to QI measurements of the complex and varying geometries of the activity localised in real patients, as well as activity measurements over the time of treatment. All these issues will be addressed by this project using SPECT and PET methods, through the development of 3D printed quasi-realistic anthropomorphic phantoms and by creating a database of reference images of geometries covering typical clinical situations. The presentation will visualize the objectives and results of MRTDosimetry and invite the community to participate and share their knowledge.
        Speaker: Hannah Wiedner (BEV)
      • 187
        Uncertainties in measuring absorbed dose from a low-energy miniature X-ray source
        ## Introduction ## In brachytherapy, miniature low-energy X-ray sources offer a number of advantages over traditional radioactive sources. These include their ease of portability, and reduced regulatory and shielding requirements. However, the dosimetry of these devices is challenging due to their steep dose gradients, soft X-ray spectra (< 100 kV) and influence of target spectral lines. Accurate and precise knowledge of the absorbed dose would allow for better confidence in target dose delivery, tracking of dose to organs at risk and optimisation of treatment plans. A greater understanding of the delivered dose is also important for combining modalities (i.e. brachytherapy with external beam radiotherapy), and for exploring treatments with these devices in other cancer sites. In this work, we evaluate the uncertainties in the measurement of absorbed dose to water from a commercially available miniature X-ray system, the INTRABEAM System (Carl Zeiss, Germany). The dose measurement method investigated was an air-kerma calibrated ionization chamber situated in a water phantom with the INTRABEAM. ## Methodology ## Depth-dose rate measurements were performed with the INTRABEAM System X-ray source (XRS) using a dedicated water phantom offered by Zeiss. The self-shielded phantom includes a platform stage for mounting and positioning the XRS, and two waterproof holders for mounting a soft X-ray ionization chamber (PTW 34013 parallel plate chamber) connected to an electrometer. Charge measurements were performed at depths between 1.7 to 20 mm from the source tip. The absorbed dose rate to water was calculated from the measured charge by two different methods: the absorbed dose formula recommended by Zeiss, and our own derived dose formalism for ionization chambers calibrated in terms of air-kerma. This dose formalism relies on a Monte Carlo (MC) calculated conversion factor, $C_Q$, to go from air-kerma in a reference beam to absorbed dose to water at a beam quality of interest. This conversion factor was calculated using the EGSnrc particle transport code. The sources of uncertainty investigated in the dose measurement were: - source positioning accuracy - uncertainty in the geometry of the PTW 34013 ionization chamber in the calculation of $C_Q$ - MC statistical uncertainty in the calculation of $C_Q$ The dose uncertainty associated with source positioning error was determined by calculating the percent difference in dose due to a depth shift of 0.1 mm. The uncertainty due to geometry tolerance was evaluated by calculating $C_Q$ with the maximum and minimum chamber cavity dimensions as specified by the manufacturer. Assuming a rectangular distribution, an uncertainty was extracted from these extreme values. Lastly, the statistical uncertainty of $C_Q$ was estimated by the standard error in the tally statistics as reported by EGSnrc. The total combined uncertainty in measured dose was estimated by adding these effects in quadrature. ## Results ## Due to the steep dose gradients near the INTRABEAM source, the dominant source of uncertainty was determined to be in the source positioning. A positioning error of 0.1 mm led to an uncertainty of 7 % in absorbed dose at a depth of 3 mm in water. This uncertainty decreased as a function of depth to 1.4 % at 20 mm. In the calculation of $C_Q$, the dimensional tolerance of the PTW 34014 ionization chamber had a significant contribution to the uncertainty, ranging from 5.6 to 1.8 %. The MC statistical uncertainties were kept below 1.2 %, and could be further reduced by increasing the total number of particle histories in the simulations. The total uncertainty in measured dose was found to range from 8.9% at 3 mm, to 2.8 % at 15 mm depth in water. However, the absorbed dose as calculated using the recommended formula was shown to disagree with the results from our method by up to 14.8 %, going beyond the uncertainties investigated in this work. ## Conclusion ## Despite all their advantages, accurate dosimetry of miniature low-energy X-ray sources remains a challenge. Steep dose gradients lead to large dose uncertainties, both from source positioning error and ionization chamber dimension variations. The results of this work show a measurement uncertainty of up to 8.9 % at 3 mm depth, which reduces with increasing distance from the source (2.8 % at 15 mm). To reduce this uncertainty further, another ionization chamber with tighter dimension tolerances could be investigated.
        Speaker: Peter Watson (McGill University)
      • 188
        Can desktop 3D printers be used to build patient specific heterogeneous phantoms for QA purposes?
        Purpose: To investigate the feasibility of making a heterogeneous humanoid phantom from the CT DICOM image set of actual patient using a commercially available desktop 3D printer and cost effective materials that have radiological characteristics of human tissue and bone Methods and Materials: gMAX 1.5XT+ Desktop 3D printer (gCreate, NY) was used to build a 3D model reconstructed from a portion of the CT of the CIRS-Thorax phantom model 002LFC (CIRS Inc). The filament type used to print this phantom is PLA (PolyLactic Acid), which is a biodegradable plastic. The 3DSlicer (3DSlicer, MA), which is a free open source software package for visualization and image analysis, was software used to convert DICOM image CT to a Stereolithographic (STL) format, which is the format of 3D object compatible with all 3D printers The 3DSlicer can extract or segment a specific density with specific Hounsfield Unit (HU) object from any DICOM CT image set, and then this segmented object can be imported by the 3D printing software to prepare it for printing. In this study, the bone structure of the CIRS phantom was extracted from the CT image set in order to keep only the tissue medium. There are many printing parameters that control the printing process and the filament consumption as well. In order to save the amount of filaments, we have selected very low (2%) infill ratio (defined as how much a solid model should be filled-in with material when printed), this will save us time and reduce the amount of filament consumed to print this phantom. with bone and air materials were extracted from the image and replaced by empty space. Then a silicon solid gel material was used to fill the tissue equivalent areas and left for an hour to dry. The bony area (extracted) was filled with gypsum powder (hydrated calcium sulfate CaSO4·2H2O) that was mixed with water. Results: The processes of printing 4 cm thick slice of the CIRS phantom with 2% infill ratio and 100 mm/sec print speed took 3-4 hours. The infill ratio used to generate a wall that is strong enough to contain the materials added inside the phantom (i.e. silicon in tissue equivalent regions gypsum in bone equivalent regions). Figure 1 shows the axial slice of the actual CIRS phantom and that of the 3D printed one. As a last step, a CT Image set was acquired for our phantom, the HU value was ranging from -8 to 10, with relative electron density of 0.984 up to 0.998. Whereas for gypsum material, the HU value was ranging from 1070 to 1150, with relative electron density of 1.63 up to 1.72, which represents the relative electron density of cortical bones (1.65-1.7). Conclusions: The process of making a portion of heterogeneous humanoid phantom from the CT image set of every specific patient is possible and can be optimized to be cost and time effective. The air gaps showing on the CT image of the 3D printed CIRS phantom (figure 2) can be avoided by using casting liquid silicon, which will fill all the space without air bubbles and without leaking outside the 3D printed phantom. By mixing water with gypsum in different proportion, we can obtain different bone type (spongy, cortical, etc.). All difficulties faced in our first trail will be avoided in our next 3D printed phantom, especially when the casting silicon liquid arrives.
        Speaker: Ahmad Nobah (King Faisal Specialist Hospital & Research Centre)
      • 189
        Evaluation of IGRT techniques in prostate cancer patients with registration of bony anatomy and implanted gold markers
        Introduction Our IGRT protocol for external beam radiotherapy for low and intermediate-risk prostate cancer patients requires registration of internal fiducial gold markers implanted in the prostate. On the other hand, registration of images of the setup fields at high-risk prostate cancer patients are based on bony structures without using gold markers, which might require larger margin for the prostate. The aim of this study is to determine the accurate CTV-PTV margin of the prostate for patients treated without gold markers. Methodology In this retrospective study, 10 low and intermediate-risk prostate cancer patients with 3 implanted internal fiducial gold markers were selected for evaluation. Varian TrueBeam linear accelerator was used for the treatments and the patient position verifications were based on a kV-kV image pair before each fraction. In agreement with our protocol, either simultaneously integrated boost or traditional sequential irradiation technique was applied, thus 28-39 sets of image pairs were registered for each patient. The patients were treated after online matching using the gold markers. Varian Offline Review option was used by two independent observers with manual matching in 3 directions on two perpendicular images according to bony anatomy (Figure1). Vertical (VERT), longitudinal (LONG) and lateral (LAT) differences between the online and offline matched positions were calculated. Differences between skin-marked setup position and online corrected position were also read out in order to calculate margins if daily image guidance is not available. According to the van Herk equation, standard deviations of the systematic and random treatment set-up errors for all patients in all three directions were calculated. Finally, CTV-PTV margins for prostate were determined for the two scenarios. We investigated if the overall mean population errors are greater than the standard deviation of the errors. Results On average, 31 sets of kV image pairs were involved in the study. In case of daily image guidance, the systematic set-up errors were found 3 mm, 2 mm and 1 mm and the population inter-fraction random errors were 2 mm, 2 mm and 1 mm in VERT, LONG and LAT directions, respectively. The overall mean systematic errors for all patients were 0.1 mm, 0.4 mm and 0.1 mm in VERT, LONG and LAT directions, respectively. Without image guidance, the systematic and inter-fraction random errors were 4 mm, 4 mm, 2 mm and 5 mm, 3 mm, 2 mm in VERT, LONG and LAT directions, respectively. For this scenario, the overall mean systematic errors were 1 mm in VERT direction and 0 in the other two directions. These values resulted in 9 mm, 7 mm, 3 mm and 11 mm, 12 mm, 7 mm margins for the prostate in VERT, LONG and LAT directions if daily image guidance is applied or not, respectively. Currently, our clinical protocol requires 8 mm and 10 mm uniform margin in case of the above mentioned two scenarios. The standard deviation of the sampling distribution in each direction was determined and no statistically significant systematic errors were detected. Conclusion The results show that applying daily image guidance and matching the image sets according to bony structures without internal fiducials could reduce the margin with 2 mm, 5 mm and 4 mm in VERT, LONG and LAT directions. Besides, if internal fiducials are applicable and daily image guidance is available, on average an additional uniform 3 mm margin reduction is applicable. The overall mean systematic errors do not indicate any large inaccuracy in our set-up procedure, however further investigation with larger population is recommended for statistically stronger results.
        Speaker: Barbara Bencsik (National Institute of Oncology)
    • Wednesday afternoon - Poster Presentations - Screen2
      Convener: Mr Oleg Belyakov (IAEA)
      • 190
        Comparison of two techniques for irradiation of the breast and the regional lymphatics - helical tomotherapy and 3D conformal radiotherapy
        Purpose: The breast cancer is the most common malignancy among women in our country. In the National Hospital of Oncology we have been treated about 600 patients per year. The purpose of the study is to present treatment planning protocols for left and right site breast irradiation, when the planning target volume include the involved breast (PTV), and supraclavicular lymph nodes (PTV_SCLN) using helical tomotherapy and to compare with “one isocenter” 3D conformal radiotherapy. Methods and Materials: The irradiation was planned for 10 real patients with left and 10 with right breast cancer using “one isocenter” technique, which is our protocol for irradiation with an isocenter situated at the lower edge of the supraclavicular part of the target volume, and asymmetrically irregularly MLC collimated beams. Tomo Helical plan was developed for the same patients using field with – 5.048 cm, pitch 0.22 cm and Modulation Factor 3. The fall-off of the dose was controlled by help contours at a distance of 1,5cm form PTV and PTV_SCLN. Directional blocking was applied to the heart and contralateral breast and lung. The planned total treatment dose was 50 Gy for both PTV and PTV_SCLN. The critical organs were: contralateral breast, ipsilateral and contralateral lung, heart and liver. For evaluation dose volume histograms were used. Results: The average results with standard deviation (SD) for Tomo helical and 3D CRT plans are presented in Table1. The averaged minimum dose for PTV in 2 ccm (Dmin2ccm) increased from 25.9 ± 6 Gy for 3D plans to 39.7 ± 1 Gy for tomo helical and for PTV_SCLN from 37.8 ± 1.6 Gy to 45.4 ± 0.6 Gy. The maximum dose in 2ccm (Dmax2ccm) decreased for PTV from 54.51 ± 0.6 Gy for CRT plans to 52.7 ± 0.4 Gy for tomo, and from 55.2 ± 0.6 Gy to 51.8 ± 0.2 Gy for PTV_SCLN. The homogeneity index (HI=(D_(2%)-D_(98%))/D_mean ) was HIPTV_tomo = 0.09 ± 0.01; HIPTV_SCLN_tomo = 0.06 ± 0.01, respectively HIPTV_3DCRT = 0.29 ± 0.04 and HIPTV_SCLN_3DCRT = 0.23 ± 0.05. The conformity index for PTV+PTV_SCLN (CI=V_(98%)/V_PTV ) was CITomo = 1.03 ± 0.1; CI3DCRT = 0.94 ± 0.1. For both techniques, ipsilateral lung received the same middle dose - 13 Gy (+0.3Gy; -0.7 Gy), the volume obtained 30 Gy was 8.5% higher in the CRT plans but the dose received in 65% of the lung volume was 3 Gy more for Tommo helical. The middle dose for contralateral lung was 3.5 Gy lower for 3D CRT (1.2 Gy vs 4.8 Gy). Heart’s average dose for left breast cases was 5 Gy greater for helical plans, but in 3D CRT plans Dmax was10 Gy more and V30Gy was 3.6% vs 0.6%. The average dose in contralateral breast was 2.5 Gy more in tomo helical plans. The liver in right breast cases with 3D CRT plans got 5 Gy less average dose but 7 Gy more for Dmax. The average irradiation time for 3D CRT with gantry rotation was 5.2 minutes, for tomo helical - 6.5. Conclusion: The conformity and homogeneity of PTVs were better for helical tomotherapy plans than the 3D CRT for both left and right breast tumor with regional lymph node involvement. The organs at risk: ipsilateral lung, contralateral lung, contralateral breast, heart and liver received a higher average dose in tomo helical plans, but lower maximum dose and a low dose in adjacent to PTVs part of their volume. There was no significant difference in irradiation time. Key words: Treatment planning, Breast cancer, 3D conformal radiotherapy, Helical tomotherapy
        Speaker: Neli Gesheva-Atanasova (National Hospital of Oncology)
      • 191
        Multiple brain metastases treatment, dosimetric comparison of IMRT vs VMAT, is there any gain?
        INTRODUCTION: Volumetric Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) have been used in brain radiosurgery in terms of non coplanar rotational arc beams with the aid of circular cones to provide beam collimation. The goal of this study is to evaluate two treatment techniques VMAT and IMRT in the treatment of intracranial metastases and to compare results between them. The issues discussed in this study with regard to not only the beam characteristics but also the dosimetry features. Both the pros and cons of both techniques are presented. 37 Lesions in 10 patients treated with VMAT were re-calculated in IMRT, for its comparison in parameters of dosimetric homogeneity, target conformation, organs at risk (OAR) protection, monitor units used, treatment time per fraction used in the 2 described techniques, PTV volumes >14 cc and target dose 40 Gy in 10 Fractions. MATERIALS AND METHODS: We evaluate the mean dose to normal brain tissue, maximum dose to OARs. Patients were simulated in Computed tomography (CT) simulation General Electric (GE) Optima model, slides acquisition 1.25 mm; Magnetic Resonance was also done in a Siemens de 1.5T with 1 mm slices in contrast enhanced T1 MPR, T2 Flair, T2 Ciss, Diffusion, Perfusion, DTI Tractography; image fusion for PTV and OAR contouring; calculation were done in Monaco® planning system version 5.10.02 with Monte Carlo algorithms; treatment delivery were make in a LINAC Elekta Infinity™ with Agility™ head with 160 interdigitating leaves with 0.5 cm width at isocenter; positioning verification XVI versión 4.5.1 b141. Dosimetric analysis were made in regard to conformity Index RTOG (CI-RTOG), homogeneity index (HI-RTOG), Paddick inverse conformity Index (PCI), Dmean. OARs were analyzed in terms of Dmax and Dmean. RESULTS: Treatments were assessed regarding to the on beam time. Dosimetric conformity, homogeneity and OAR were comparable between IMRT and VMAT single Arc, Treatment Delivery time 16 +/- 1.30 minutes for IMRT and 2 +/- 0.20 minutes for VMAT 1 arc. Mean MU were 1130 and 903 for IMRT, and VMAT 1 arc plans, respectively. CONCLUSIONS: Data found in this study suggest that VMAT and IMRT plans are clinically comparable in terms of CI, HI, and OAR restrictions. However there is a substantial difference on beam time and fewer MU for VMAT compared to IMRT. This MU reduction is important due to limits in the exposition time to the resultant leakage radiation even though it is minimum due to Agility™ head used for the treatment. Fewer on beam time limits the inter-fraction potential uncertainties due to OAR and PTV movements, what could lead considerable dosimetric variations. This important clinical advantage makes VMAT a safe and efficient treatment technique for multiple brain metastases more than 14 cc volume with controlled extracranial disease.
        Speakers: David Antonio Martinez Perez (Radiation Oncology Department, Medical Resident, Oncosalud, AUNA - Lima, Peru) , Gustavo Sarria Bardales (Radiation Oncology Department, Principal Professor; Oncosalud, AUNA - Lima, Peru)
      • 192
        The “CLAWS” – An applicator for whole-eye radiotherapy
        Introduction: Ophthalmic tumors are fairly rare and diverse and their diagnosis and treatment usually requires special expertise and equipment, including patient care by a multidisciplinary team. Brachytherapy is the preferred radiation treatment modality for various intraocular tumors and the most commonly used radionuclide is I-125. The “Claws” is a gold applicator that is loaded with I-125 seeds for localized whole-eye radiotherapy. It was designed at Groote Schuur Hospital. The applicator is mainly used to treat retinoblastoma, a childhood cancer of the eye. Methods: Under general anaesthesia, a pericorneal ring is attached to the four extra-ocular muscles, and four appendages, each loaded with I-125 seeds, are inserted beneath the conjunctiva in-between each pair of muscles and attached anteriorly to the ring. The applicator has an inside diameter of 22 mm. Current dose calculations approximate each I-125 seed as a point source, and a project is underway to improve the dose calculations, and particularly the dose to critical structures in and around the eye, based on Monte Carlo calculations. Spectra of the OncoSeed IMC6711 seed at different angles were measured in air using a silicon drift detector. Seed measurements in specially designed phantoms were done using thermoluminescent dosimeters and gafchromic film. A CAD model of the “Claws” was designed and used to manufacture a PVC model in a milling machine, which was then micro-CT scanned at a 20 µm resolution. The CAD model was also cut into 20 µm slices; these will be edited and used as input for Monte Carlo simulations. Results: The applicator irradiates the eye with minimal dose to the surrounding bony orbit, extraocular optic nerve, eyelids and lacrimal gland. Certain seeds may be omitted to reduce the dose to the unaffected parts of the eye. A typical treatment prescription is 40 Gy given over four days to the centre of the eye. General anaesthesia is also required for the removal of the applicator. Conclusion: The applicators are cost-effective because they can be re-used. The I-125 seeds are regularly used for other eye plaques and implants. The eye does not need fixation during treatment and cosmesis is excellent. The Monte Carlo simulations will take into account the gold shielding of the applicator and the anisotropic dose distribution around the I-125 seeds, which will give a better estimation of the dose to the organs at risk.
        Speaker: Christoph Trauernicht (Groote Schuur Hospital)
      • 193
        Planning implementation of a hybrid VMAT (H-VMAT) in radiation therapy treatments of head and neck cancer cases; a dosimetric comparison with IMRT and VMAT; should we move on?
        INTRODUCTION: For head and neck cancer (H&N) It was compared three treatment techniques as volumetric modulated arc therapy (VMAT), Intensity Modulated Radiotherapy modality sliding Windows (IMRTsw), and Hybrid treatment thechnique (H-VMAT), the latter consists in blend both techniques VMAT and IMRTsw and give different weights for each during planning. The research is to compare the dosimetric distributions, and observed gains with regard to dose distribution, treatment time and scattered radiation imparted to the patient. MATERIALS AND METHODS: For a patient with a Head and Neck Cancer diagnose we decided to compare treatments described above, patient was simulated in supine position, inmobilized by using thermoplastic mask, in all cases positioning was verified by using cone beam (XVI), patients were planned with the three treatment techniques to the case of VMAT (1 arc) and for IMRTsw (5 fields). Patients were simulated in Computed tomography (CT) simulation General Electric (GE) Optima model, slides acquisition 1.25 mm; Magnetic Resonance was also done in a Siemens de 1.5T with 1 mm slices in contrast enhanced T1 MPR, T2 Flair, T2 Ciss, Diffusion, Perfusion; image fusion for PTV and OAR contouring; calculation were done in Monaco® planning system version 5.10.02 with Monte Carlo algorithms; treatment delivery were make in a LINAC Elekta Infinity™ with Agility™ head with 160 interdigitating leaves with 0.5 cm width at isocenter; positioning verification XVI versión 4.5.1 b141, Calculations were verified with PTW OCTAVIUS System. H-VMAT treatment modality consist in use IMRT fields and VMAT Archs blended with with the new bias dose option (B) This allows us to account for doses previously planned for a patient in a new plan during the optimization proccess, and different weights deliver treatments to achieve lower dispersion and higher tumor dose conformality. When compare dose distribution shown in figure 1, it is observed that 5% (Blue) dose is less in H-VMAT; what reflects less scattered radiation, with regard to 5% scattered dose is less with H-VMAT as is with the hot points as well. Dosimetric analysis were made in regard to conformity Index RTOG (CIRTOG), homogeneity index (HIRTOG), Paddick inverse conformity Index (PCI), Dmean. OARs were analyzed in terms of Dmax and Dmean. Ptv: volume tratement planification Conformidad index: (ICRTOG) Homogeneity index (HIRTOG) Dmax: Maximun Dose Dmin: Minimun Dose Dmean: Mean Dose Paddick inverse conformity Index (PCI): Table N°1 It is observed for H-VMAT that CI, HI, Paddick Index, are better than those for IMRT or VMAT alone, nor for MU that are in between of the mean values. Table N° 2 it is observed the values distribution in Gy, between PTV volume in H-VMAT compared to IMRT 5 Field and VMAT 1 Arc, showing 2%, 50% and 95% volume isodose distribution; and it is seen that cGy given to PTV are less in H-VMAT leading to a better isodose distribution and homogeneity, having in count that the prescribed dose is 6600cGy. Table 3 Shows patient dose distribution, 5% Isodose (330cGy) for H-Vmat the % is fewer compared in volume cc, to IMRT and VMAT alone, that allow us to control more efficiently the possible colateral effects that its could lead to. Also it is observed a gain in the 50% isodose being less for H-VMAT. It is observed that the maximum dose distributed in IMRT is bigger, and mean dose is closer to the prescribed dose in H-VMAT. In Table N°4. Dose max is less for HMAT in comparison with VMAT and IMRT. In conclusion the hybrid H-VMAT technique shows improvments from the treatment time compared to IMRT, dose distribution and less scattering to VMAT, making it a good option in the Radiation therapy planning for head and neck cancers.
        Speaker: Bertha GARCIA (RED AUNA - Clinica Delgado)
      • 194
        Implementation of IMRT technique in treatment of prostate cancer Experience of oncology radiotherapy department of Habib Bourguiba Hospital
        Purpose : The aim of our study was to share our transition experience from 3D conformal radiotherapy to intensity modulated radiotherapy (IMRT) in treatment of prostate cancer. Patients and methods : From 2011 to 2016, 84 patients were consequently treated with curative intent for localized prostate cancer with 3D conformal radiotherapy in 46 cases (group 1) and IMRT in 38 cases (group 2). The median age was 69.5 years (50-81 years). According to D'Amico classification, 25 patients (54.3%) and 29 patients (76.3%) were at High risk in group 1 and 2 respectively. The positioning control was made by repeated portal imagery (PI). The objective was to carry out a PI per week for the 3D technique and at least 3 PI per week for the IMRT technique. Patients were followed weekly during treatment to determine the acute toxicities which were graded according to the Common Terminology Criteria for Adverse Events (CTCAE) v.4. Results : The dose of radiation was greater or equal to 74 Gy in 19 patients (41.3%) of the first group and 31 patients (81.7%) of the second group. No patient in the first group had prophylactic lymph node radiotherapy against 20 patients (52.6%) of the 2nd group. The median number of PI during treatment was 8 (3-11) for the first group and 15,5 (6-40) for the second group. We note that for the first 7 patients treated with IMRT IP was repeated almost daily to a better control. During radiotherapy 42 patients (91.3%) in group 1 had developed urinary toxicity, including three patients with Grade 3 toxicity. In addition, 18 patients (39.1%) had gastrointestinal toxicity, mainly grade 1 (17 patients). For the second group, 36 patients (94.7%) had developed urinary toxicity grade 1 in the majority of cases (73%). Gastrointestinal toxicity was found in 18 patients (47.3%), mainly from grade 1 (14 patients). No grade ≥ 3 toxicity was noted. The difference was not significant between the 2 groups. Conclusions : The results of our study show that IMRT allows dose escalation beyond 74 Gy and prophylactic lymph nodes irradiation without increasing incidence and grade of acute toxicities with essentially the absence of acute toxicities ≥ grade 3. On the other hand the IMRT was associated with an increase of the time of occupation of the treatment machine especially in relation, with the repetition of the PI.
        Speaker: Hend Daoud
      • 195
        Dosimetric evaluation of dose distributions delivered to an in-house developed respiratory chest phantom
        **Introduction** In radiotherapy, intra-fractional movement of organs can cause important discrepancies between planned and delivered dose distributions. The magnitude of the discrepancy will depend on several factors, including the range and direction of organ movement, the margins of the planned distribution, the algorithm used for the dose calculation and the type of treatment, among others. The photon radiotherapy treatments of tumors located in the lungs are therefore especially prone to face this challenge. There are several techniques that have been clinically implemented to deal with the issue of organ motion during the delivery of the treatment; respiratory-gating is one of those. **Objectives** The purpose of the study was to assess the impact of the respiratory motion on the delivered dose distributions to an in-house developed respiratory phantom by using different dosimetric systems, planning strategies and delivery conditions, including respiratory-gating. **Materials and methods** The chest phantom consisted in a rigid plastic frame with two cavities simulating the lungs mounted in a platform which allowed the installation of motor powered mechanical systems that moved a simulated tumor inside the lung and a vertical platform above the surface of the phantom. The simulated tumor target was a 4 cm diameter sphere made of plastic. This was able to move in different directions (longitudinal and rotational) for user defined waveforms, as it was connected through an insert to the external mechanical system. The platform simulating the chest surface, where markers are placed to act as surrogates of tumor motion, moved vertically also following a predefined waveform. The movement of the target and the platform was computer controlled by a program developed in LabView, allowing the user to control the waveform parameters and correlation between the surface and tumor motion. Inside the tumor, it was possible to measure the delivered dose using different dosimetric systems: a photon diode, TLDs and radiochromic films. The phantom was scanned and different treatment plans were elaborated. The plans included different strategies for motion management: no motion consideration, increased margins and respiratory gating. The dose was computed using pencil beam, collapsed cone and Monte Carlo based algorithms and then delivered to the phantom in static and dynamic modes. The dose calculated by the treatment planning system for the target was compared with measurements made by the detectors inside the tumor and evaluated. **Results** It was found that the abrupt changes in density between the target material and the air surrounding it made it very challenging for the calculation algorithm to reproduce the delivered dose, generating values that overestimated the dose within the target, even in static conditions. The differences were up to 8% in the center of the target, where the discrepancies between algorithms were smaller compared to the borders of the target. Therefore for the rest of the study only Monte Carlo based calculations were used, as it was the only algorithm able to reproduce the delivered dose in the experimental conditions. As expected, important differences from the prescribed dose were found if no motion compensation strategy was applied (up to 20%) for a longitudinal movement of 8 mm range. For the gated-therapy case, a very good agreement between measured and planned distributions was found (within 2%). The discrepancies for the gated case indicated that its implementation would not increase the uncertainty in the delivered dose, as the differences between measurements and calculation for a static plan (no motion management) and delivery were of the same order. **Conclusions** The study confirms the importance of using an adequate dose calculation algorithm when dose calculations are performed in the presence of inhomogeneities where there are abrupt changes of electron densities. Otherwise, the dose can be overestimated for the target and underestimated in the surrounding healthy tissues, in lung tumor cases. The phantom was useful to reproduce clinically relevant conditions and to evaluate the effect of intra-fractional target motion. Its design would additionally allow for the estimation of dose uncertainties related to the implementation of other motion management techniques such as tracking and respiratory gating using only an external surrogate, such as a reflective marker or a pressure belt.
        Speaker: Paola Caprile (Pontificia Universidad Católica de Chile)
    • Wednesday afternoon - Poster Presentations - Screen3
      Convener: Mr Oleg Belyakov (IAEA)
      • 196
        Dosimetric evaluation of newly developed well-type ionization chamber for use in the calibration of brachytherapy sources
        PURPOSE: To evaluate the dosimetric characteristics of newly developed well-type ionization chamber and to compare the results with the commercially available calibrated well-type ionization chambers that are being used for the calibration of brachytherapy sources. METHOS AND MATERIALS: The newly developed well-type ionization chamber (BDS 1000) has been designed for convenient use in brachytherapy. The chamber has a volume of 240 cm3, weight of 2.5 Kg and the chamber is open to atmospheric conditions. The chamber characteristics such as leakage current, stability, scattering effect, ion collection efficiency, air-kerma strength and nominal response with energy were studied with the BDS 1000 well-type ionization chamber. The evaluated characteristics of BDS1000 well-type ionization chamber were compared with two other commercially available well-type ionization chambers. RESULTS: The measured leakage current observed was negligible for the newly developed BDS 1000 well-type ionization chamber. The ion collection efficiency was close to 1 and the response of the chamber was found to be very stable. The determined sweet spot was 42 mm from bottom of the chamber insert. The overall dosimetric characteristics of BDS 1000 well-type ionization chamber were in good agreement with the dosimetric characteristics of other two well-type ionization chambers. CONCLUSION: The study shows that the newly developed BDS 1000 well-type ionization chamber is high in sensitivity and reliable chamber for air-kerma strength calibration. The results obtained confirm that this chamber can be used for the calibrations of HDR and LDR brachytherapy sources.
        Speaker: Sathiyan Saminathan (Kidwai Memorial Institute of Oncology)
      • 197
        Evaluation of metallic implant artefact on photon beam calculation algorithms: a study using CIRS thorax phantom
        The aim of this study was to evaluate the effect of metallic artifact on dose calculations for patients with metallic implants and to find ways in reducing the errors associated with actual dose delivered. The error magnitude in dose calculations using two different treatment planning system (TPS) algorithms and dose measurements in a CIRS (Model 002LFC) IMRT thorax phantom with a metal insert in the spine was assessed for two different CT window settings. As described in figure 1, the CIRS phantom was CT scanned using an adult thorax routine for two sets of images (i.e. Mediastinum and Osteo window settings). A 3D anterior-posterior (APPA) conformal treatment plans (using 6MV and then 15MV photon beams) was done using a typical 2 Gy to a target volume (point 5 on the CIRS phantom) with a Collapsed Cone (CC) and Pencil Beam (PB) calculation algorithms for both CT image sets. Maintaining the same parameters, the plans were recalculated using a corrected image set (overriding the metal density in the artifact region with that of water). Doses to the selected point of interest in the phantom were measured using a calibrated PTW Farmer ionization chamber TM 30010 and a PTW UNIDOS webline electrometer based on the techniques as described in IAEA TRS 398 and compared with the TPS calculations. Average discrepancies of 2.4% and 5.2% for 6MV and 4.6% and 4.5% for 15MV between calculated and measured doses were observed for collapsed cone and pencil beam algorithms respectively using the mediastinum CT window setting. For the Osteo window setting, discrepancies of 2.7% and 3.1% for 6MV and 5.0% and 2.7% for 15MV between calculated and measured doses were observed for collapsed cone and pencil beam algorithms respectively. Correcting for the metal artifact by overriding its densities in CT sets during planning gave higher average dose discrepancies of 16% for both energies. This suggests that caution should be exercised when using only corrected metal artifact CT scans for dose calculations in TPS as it only gives superior isodose coverage but not the actual dose to selected point of interest. The results as captured in table 1 of this study indicated the shortcomings of the PB algorithm and higher photon energy for the test case performed and, therefore the use of the CC algorithm and low photon energy is highly desirable. There was no statistically significant difference according to the kinds of CT window settings used. In addition, it will be necessary in the future to consider the use commercial metal artifact reduction tool for clinical routine to help avoid misinterpretation of dose distributions during planning.
        Speaker: George Felix Acquah (Sweden Ghana Medical Centre)
      • 198
        Workshop summary - Design characteristics of novel radiotherapy technology for challenging environments: improving access to radiotherapy
        Many low-to-middle income countries (LMICs) suffer from a debilitating lack of radiotherapy. This problem will only be exacerbated with the increase in cancer incidence expected in these nations. The Global Task Force on Radiotherapy for Cancer Control, a Commission of the Lancet Oncology, estimated 12 600 megavoltage treatment machines are needed to meet the radiotherapy demands in LMICs by 2035. Limiting factors to the development and implementation of radiotherapy in lower resourced nations include cost of equipment and infrastructure and the shortage of trained personnel to deliver high quality treatment. The Lancet report was one of several publications that discuss the need for radiotherapy in LMICs, however less frequent in the literature are insights into how these barriers can be overcome. CERN and the International Cancer Expert Corps will be hosting a workshop on November 7 and 8, 2016 to have a fulsome discussion on the needs for radiotherapy and possible solutions to conquer the challenges faced by LMICs. The two day workshop will bring together a group of invited experts in radiation oncology, engineering, telecommunications, and particle accelerator technology to discuss the design requirements of linear accelerators and other technologies in LMICS. The 11 distinct sessions in the workshop explore all facets of issues faced by LMICs who want to include external beam radiotherapy as part of their cancer control strategy. The wide breath of topics include a description of the global radiotherapy gap, reviewing past experiences of implementing radiotherapy into LMICs, understanding what technology requirements are essential for radiation treatments in low resourced environments, and exploring novel techniques to develop a skilled workforce. Advances in particle accelerators, designed to function in areas with limited infrastructure, will be presented by members of CERN followed by discussions on the practicalities around bringing innovations to these settings. Findings from the meeting will be summarized in a subsequent report – its contents will be the subject of this session.
        Speaker: David Jaffray (University Health Network)
      • 199
        Frameless volumetric intracraneal stereotactic radiosurgery with non coplanar arcs: clinical experience, accuracy and dosimetric evaluation
        INTRODUCTION: In the last decades technological advances are increasing with the development of new treatment techniques and ways to deliver cranial radiosurgery (SRS), that is based into precision and accuracy, Volumetric Arc Therapy (VMAT) have been used in brain radio surgery in terms of non coplanar rotational arc beams with the aid of multi-leaf (MLC) to provide beam collimation. Using the traditional Leksell Stereotactic System, the time to do a treatment in average was around 6 hours; however the workflow using a frameless system decreases the mean treatment time in less than an hour, turning out to be a resources optimization for its realization, all this with the help of all accessories, quality assurance that should be made before deliver a proper treatment. The goal of this study is to show our clinical experience doing frameless SRS, with VMAT technique in the treatment of Arteriovenous Malformations (AVMs), Brain Metastases (BM), Meningiomas, among others. The issues discussed in this study with regard to not only the clinical features, but also beam characteristics, and dosimetric features.
        Speaker: Bertha GARCIA (RED AUNA - CLINICA DELGADO)
      • 200
        Evaluation and validation of the Fast Superposition, Superposition and FFT Convolution algorithms for IMRT of low density treatment sites on CMS XiO Treatment Planning System.
        Dose calculating algorithms play an important role in patient treatment planning in radiotherapy. Morden complex treatment techniques for example intensity modulated radiotherapy (IMRT) require accurate and fast dose calculating algorithm to enhance delivery of quality in the treatment of low density sites. The study evaluated three algorithms used in IMRT and these include Superposition, Fast Fourier Transform (FFT) Convolution and fast Superposition. These algorithms were evaluated when applied to low density treatment sites, which include larynx, stomach and lung. An inhouse phantom with low density material was designed and constructed for use in both point dose and planar dose distribution measurements using ionisation chamber and MapCHECK 2 respectively. The evaluation involved a comparison and quantification of deviation between the TPS predicted dose and that experimentally measured, for each algorithm and treatment site. The percentage deviation of the ionometric measurements was between ±2.09% and ±6.03%, while the gamma index method had > 80% points satisfying the acceptance criteria of (3%/ 3mm). Therefore the outcome of the IMRT treatment is affected by the choice of the algorithm per each treatment site. An affordable inhouse phantom can be used for algorithm evaluation.
        Speaker: Walter Nyakodzwe (The Cancer Center Bahamas)
      • 201
        Is there a role for Cobalt-60 radiation therapy in the world
        Introduction: The invention of the cobalt-60 (Co-60) treatment unit in the 1950’s established high energy radiation therapy, but the use of Co-60 treatment began to decline in the late 1970s. At that time linear accelerator based radiation treatment became prevalent, especially in the developed world where today utilization standards recommend that 50% of cancer patients would benefit from radiation therapy at some time during their care. Recently, the World Health Organization has reported that low and middle income countries (LMICs) account for over 60% of the world’s new annual cases of cancer and over 70% of the world’s cancer deaths. However, despite being home to 85% of the world’s population, LMICs have less than 35% of the world’s radiotherapy facilities. It is evident that most cancer patients in LMICs do not have access to beneficial radiation treatment. Until recently Co-60 units still served a dominant role in many LMICs, mainly because these reliable devices are simple and robust, and require manageable maintenance programs and little facility infrastructure. But Co-60 based radiation therapy has dwindled also in LMICs and its use is not considered even in areas that could benefit from it. We postulate that this can be attributed to a lack of development of Co-60 treatment machines and, until recently, a lack of evidence that modern dose delivery techniques are feasible with Co 60. In this paper we will present results of our research advancing modern Co-60 radiation therapy along with reports of image guided conformal treatment delivery with the MRIdian Co-60 unit (ViewRay, Cleveland OH), and developments of dedicated units (e.g. for breast treatment and total body irradiation), to support recommendations for further Co-60 development. Methods and Results: We have been investigating Co-60 based radiation treatment for 15 years through measurements on a Theratron 780C (T780C) Co-60 teletherapy unit (Best Theratronics) installed at the Cancer Centre of Southeastern Ontario (CCSEO). Additional equipment, such as the binary MIMiC multileaf collimator (MLC; Nomos Corp., Pittsburgh, PA), and the XRD1640 (Perkin Elmer Optoelectronics, Fremont, CA) and aSi500 (Varian Medical Systems Palo Alto, CA) electronic portal imaging devices (EPIDs) were added to the unit to emulate serial tomotherapy conformal dose delivery and enable MV imaging. The beam characterization was complemented by EGSnrc Monte Carlo simulations enabling the development of an in-house inverse treatment planning program. Results will be presented that indicate that modern radiation delivery is achievable using an existing gantry-mounted Co-60 source (Figure 1, right). Rotational treatment delivery with beam parameters modeled in a treatment planning system (including profiles under open leaves across the binary MLC) enable planned delivery to compensate for the Co-60 penumbra and penetration issues often cited as barriers to conformal delivery. Investigations of EPID imaging of anthropomorphic head, torso and pelvis phantoms (Figure 1, left) indicated that basic image guidance could be incorporated into Co-60 units. The potential for advanced image guided radiation therapy has also been clinically proven in a number of centres using the MRIdian Co-60 treatment unit. Discussion and Conclusions: The widespread perception that Co-60 devices are unable to provide suitable modern radiation treatment is incorrect. Yet this viewpoint is strong and hinders the appropriate reception of Co-60 treatment units, particularly in regions where a significant patient population may have restricted access to radiation therapy. A suitable approach to ensure that radiation therapy is made more available worldwide includes further development of conventional gantry based single source Co-60 units. Furthermore, our analysis of the current status of Co-60 radiation therapy suggests the development of three classes of Co-60 based systems: (1) fully IMRT and IGRT capable machines to provide modern state of the art treatments in clinics that require this technology, at a lower cost than linear accelerators; (2) less elaborate versions with basic imaging and conformal delivery hardware to provide basic but efficient conformal therapy, possibly through an upgrade path for clinics with basic cobalt units; and finally, (3) simple, robust Co-60 machines that can be quickly deployed in regions that currently lack any form of radiotherapy and that have limited infrastructure to enable the deployment of linear accelerators. Arguments for each of these three classes of Co-60 units will be presented.
        Speaker: L. John Schreiner (Cancer Centre of Southeastern Ontario at KGH)
    • Wednesday afternoon - Poster Presentations - Screen4
      Convener: Mr Oleg Belyakov (IAEA)
      • 202
        Radiobiological effects of cisplatin in carbon-irradiated cancer and bystander normal cells: the involvement of gap junction communication and NRF2 antioxidant system
        **Introduction** Glioblastoma multiforme (GBM) is the most common and most aggressive human brain tumor. Because most of GBM patients die of their disease and the median overall survival is approximately 1 year. In addition, GBM is difficult to treat since the tumors contain many different types of cell. To this end, the treatment plans for GBM may combine several approaches. Generally, GBM patients are treated with surgical resection together with a combination of radiotherapy and chemotherapy. Even though the plan is implemented, it does not effectively enough to prevent the recurrence and resistance of the tumor during the course follow-up. To date, the mechanisms for recurrence and resistance of GBM to radiochemotherapy that occurs within the irradiated field are not fully examined. To overcome this problem, carbon ions radiotherapy is a promising treatment modality of GBM because it is able to provide a high dose of radiation given to the tumor without the excess damage to normal tissue. Therefore, it would significantly improve survival rates in patients. However, its mechanism of action with chemotherapy in the non-irradiated bystander normal cells surrounding carbon-irradiated cancer cells has not been investigated. To address this question, we perform the in-depth investigation of the effect of combined radiochemotherapy with cisplatin in co-cultured with carbon-irradiated human GBM (T98G) cells and non-irradiated bystander human skin fibroblasts (NB1RGB) with particular emphasis on the role of gap-junction intercellular communication (GJIC) and Nuclear factor (erythroid-derived 2)-like 2 (Nrf2). **Materials and Methods** The layered tissue culture strategy that allows isolation of pure non-irradiated bystander normal cells and carbon-irradiated cancer cells was used (Fig. 1). Briefly, confluent T98G cells were treated with cisplatin, followed by carbon ions (Dose 6 Gy, LET 76 keV/um) at the biology experiment port of the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS) in Japan. Within 15-20 min following exposure, carbon-irradiated T98G cells were trypsinzied and seeded on the top of insert with normal human NB1RGB cells in the presence and absence of gap-junction inhibitor (AGA) at the bottom of it. Following co-culture for 5 h, T98G and NB1RGB cells were then harvest and assayed for colony formation, micronucleus formation and western blot. **Results** Using this co-culture system our results clearly indicate that GJIC enhances cisplatin toxicity in carbon-irradiated T98G cells and bystander NB1RGB cells. However, the cytotoxicity in the bystander NB1RGB cells can be partially suppressed by inhibiting of GJIC with AGA. The protective mechanism of AGA against the toxic effect of radiochemotherapy was assessed based on the restoration of the antioxidant defenses via activation of Nrf2. With the result obtained, it can be inferred that the activation of Nrf2 might facilitate accumulation of antioxidant enzymes within cells and can affect cell survival by increasing the repair capacity in a community of cells. Therefore, GJIC and Nrf2 significantly influence in the propagation of damaging effects of high-LET carbon ions combined with cisplatin from irradiated cancer cells to non-irradiated bystander normal cells. **Conclusion** The finding provides further insight into the radiobiological aspect of high-LET carbon ions for GBM patients that entails potential implications for clinical radiation oncology. Additional research is needed to focus on new drug with the inclusion of cisplatin that could potentially further improve the overall prognosis of GBM patients. **Acknowledgments** The author would like to thank Drs. Masao Suzuki, Teruaki Konishi, Cuihua Liu, Takeshi Murakami and the staffs in HIMAC at NIRS for their excellent support. These studies were supported by a grant from The JSPS Kakenhi, NIRS-HIMAC, The Higher Education Research Promotion, Northern Thai Research Group of Therapeutic Radiology and Oncology (NTRG-TRO), National Research University Project of Thailand (Chiang Mai University-Gynecologic Cancer Research Cluster), Office of The Higher Education Commission and Chiang Mai University.
        Speaker: Narongchai Autsavapromporn (Chiang Mai University)
      • 203
        Leakage radiation of ARTISTE LINAC machine
        INTRODUCTION Leakage radiation evaluation, as a part of acceptance tests during linac commissioning, is of paramount importance regarding patient and staff radiation protection. In this study, leakage tests were performed for a newly installed linac according to IEC 6061. METHODS I) Photon beam a) Photons leakage from head and beam transport system: In order to measure the potential leakage from the linac waveguide and the source,EDR-2 films were used to wrap around the linac head, covering all the sides of linac head except the collimator.The films should be marked to permit the determination of theirposition on the machine after they are exposed and processed. Next, a long enough exposure of 1000 MU was delivered using the 15MV photon beams in a situation that the jaws and MLC leaves were fully closed, Gantry=0, Collimator=0.In the next step, after developing the films, the leakage was measured inany area with density greater than the background or fog using an ionization chamber-style survey meter. b) Photon leakage from beam limiting system and reaching outside the useful beam: First, a 0.6 cc Farmer ion chamber(withappropriate buildup caps) was placed at SSD=100 in a 10×10 cm² field size to be exposed 1000 Monitor Unit for three times using the highest available energy. The ion chamber should be positioned along an arc of 1 meter radius circle to repeat delivering the same exposure. Finally, the results compared with the reading collected at the reference condition. II) Electron beam Cone leakage: In order to evaluate the leakage from electron cone, a ROOS ion chamber was positioned in center of radiation field at SSD=100 cm. The gantry, couch and collimator angles were set zero. The position of the ion chamber should be changed in a line 2 cm and 4 cm outside the periphery of the geometrical radiation field. 100 MU was delivered using 18 MeV exposure in each position for each measurement point. This procedure should be performed for all available applicators. RESULTS According to the head leakage test, there were no hot spots on films.Dose due to photons leakage outside the useful beam, ranged from 0.01 percent to 0.03 percentof maximum absorbed dose measured at isocentre plane in a 10×10 radiation field. As far as electron beam tests are concerned, the maximum ratio of dose at 2 cm and 4 cm from useful beam edge to dose at isocenterwere5.01% for applicator 20×20 and 2.16% for 15×15 applicator, respectively. DISCUSSION From this study, it has been found that: 1- Leakage radiation at 1 meter along the path of the electrons between gun and target not exceed 0.1 percent of the maximum dose measured at isocentre of a reference radiation field. 2- Leakage radiation at any point outside the maximum useful beam and in a circular plane of radius 1 m from isocenter also not exceed 0.2% of the isocenter. 3- Absorbed dose at 2cm outside the 18 MeV useful beam area for all applicators not Exceed 10% max absorbed dose on the reference axis at SSD=100. CONCLUSION The newly installedARTISTE linac was allowed to be used for clinical applications asall the radiation leakageparameters were within the tolerance limit specified by theIEC60-61 requirements. It is suggested that measurement of radiation leakage should be necessary during acceptancetesting of a linac machine, especially for new type machines such as the ARTISRE, toensure patient and staff safety.
        Speaker: Fatemeh Akbari (Department of medical physics, Reza Radiation Oncology Center, Mashhad, Iran)
      • 204
        A novel technique for postal intercomparison of beam Quality Assurance criterion of Proton Therapy facilities using radiochromic film EBT3
        **Introduction:** Validation of therapeutic proton field bases on daily quality assurance (QA) procedure is imperative to routine proton therapy. The ratio of delivered and measured proton dose at the reference point under “standard condition” is defined as primary QA criterion. The standard condition (R20M10) is characterized as follows: (a) proton beam energy corresponding to a range (R) of 20 cm in water, (b) beam modulation (M) depth, known as spread out Bragg Peak (SOBP) of 10 cm, (c) Field size of 10 cm x 10 cm, (d) Air-gap of 20 cm, (e) dosimetry point (reference) located at the center of the SOBP and (f) proton dose of 2 Gy delivered in a single fraction using uniform scanning (US) mode. The proton dose under standard condition in a water or polystyrene pate phantom are commonly evaluated using various active devices, including Flat plate ionization chamber (FPIC), Multi layer ionisation chamber (MLIC) or a compact QA dosimetry device (Model: QA3; Manufacturer: Sun Nuclear Corp., Florida, USA). At WPE/IBA Group in Essen, Germany we have developed a passive method of proton dosimetry under standard condition using radiochromic film (Model: EBT3; Manufacturer: International Speciality Product, Wayne, USA). A handheld optical densitometer (Model: Unilight D; Manufacturer: IBA Dosimetry, Schwrzenbrück, Germany) was used for film readout purpose. The technique does not require and active electrical power hence, ideally suited for inter-facility proton beam QA inter-comparison studies. **Methods:** We cut out six sections (8cm x 8cm) from a standard sheet (25cm x 10cm) of Gafchromic EBT3 film using a pair of sharp scissors. The sensitivity of EBT3 films depends on their orientations i.e. Landscape (LSC) or Portrait (POR) mode. In order to compensate this effect we stacked two film sections with LSC and POR orientations at right angles (90o) to each other. We have prepared six batches EBT3 dosimeter each incorporating three stacks. Five dosimeter batches were mailed to five proton therapy centres in Europe and USA operating PROTEUS Plus and PROTEUS One Medical Cyclotrons of IBA. The 6th batch was exposed under standard conditions at WPE as benchmark. The beam Quality Assurance Criterion (QAC) is defined as the ratio of net (background subtracted) optical density (NOD) of the 1st film stack exposed to a proton dose of 2Gy at the Proton Therapy Centre of interest (NODx) and the NOD of the 2nd film stack of the same batch exposed to a proton dose of 2Gy at WPE (NODwpe**strong text**) under standard condition. The optical density (OD) of the 3rd film stack (control) was used for background subtraction: QAC = (NODx/NODwpe)2Gy (1) **Results:** We have duly received the samples exposed to protons under standard conditions from ProCure Proton Therapy Center (PCPTC), Oklahoma City, USA operating a PROTEUS Plus cyclotron like ours at WPE. The delivery of exposed film samples from four PT centres are still pending. The NOD was evaluated at three spots in the central zone of the films using IBA Unilight D densitometer. The QAC was calculated using equation 1. Results are depicted in Figure 1. **Conclusion:** We have developed a robust and simple method for postal intercomparison of quality assurance criterion of proton therapy facilities. The method is based on radiochromic films widely used by medical physics fraternity. The inherent shortcomings of radiochromic films namely, orientation dependence of sensitivity and batch inhomogeneity were resolved. The usage of TLD has the pitfalls like fading, complex evaluation routine and requirements of expensive TLD reader and annealing oven. Our method outperforms the postal dose intercomparison studies using TLD. A worldwide implementation of this novel technique in commercial basis is envisaged.
        Speaker: Bhaskar Mukherjee
      • 205
        The effect of high energy photons emitted from cobalt - 57 source on extrinsic uniformity test
        Aim: During extrinsic uniformity test, to show FWHM limit excess can be observed due to using hot Co- 57 source and this excess doesn’t affect clinical imaging. Materials and Methods: One of the most important parameters that determine the performance of the gamma camera system is the deterioration of the detector homogeneity. The test is used to evaluate the collimator homogeneity is extrinsic uniformity.Cobalt -57 flood source used to evaluate the extrinsic uniformity, uniformly dispersed in an epoxy matrix fully sealed in a high integrity ABS encapsulation. Radionuclide purity is greater than 99.9% (combined Co-56/Co-58 is less than 0.08% at source reference date). Co-56 isotope emits 0.416 MeV gamma rays. Co-58 isotope emits 810keV gamma ray with 99% probability.In our clinic, extrinsic uniformity test were done for GE Infinia Hawkeye 4 – SPECT/CT on 7 December 2015 with using Co-57 10 mCi(370MBq) (source reference date 1 December 2015) on H mode by collecting 8000 kcts.For D1 detector, Co-57 flood source placed on the top of the D2 detector and measurements were done for 3, 17, 25, 30, 35 , 40 cm distances, respectively.The same procedure with same distances repeated for D2. Results: For detector D1 FWHM values were found as 12.5%, 11.1%, 10.8%, 10.7%, 10.6%, 10.6% for measurements done at 3, 17, 25, 30, 35, 40cm distances from the source, respectively.For detector D2 FWHM values were found as 12.5%, 11.2%, 11%, 10.9%, 10.8%, 10.8% for measurements done at 3, 17, 25, 30, 35, 40 cm distances from the source, respectively.FWHM value was read 12.5%, for the closest distance between detector and source, which should have been maximum 12% for extrinsic uniformity test. While increasing the distance between detector and source, this FWHM value decreased to 10.6% for D1 and 10.8% for D2. Conclusion: Exceeding the limit value of the FWHM means measurements were taken from energies outside the specified energy window range.The counting of high-energy rays emitted from the hot Co- 57 source with detectors causes FWHM to be measured beyond the value of 12% limit.Thus, waiting long enough after the date of reference calibration in direct proportion to the half-live, these differences are not observed.Besides, in clinic, these observed differences do not affect the image quality.
        Speaker: Nur KODALOGLU (Hacettepe University-Numune Research and Training Hospital)
      • 206
        Abscopal effects with non-ionizing radiation
        Introduction Radiation therapy in oncology is in most of the cases local. The malignancy (counting the circulation cancer cells and the micro- and macro-metastases) is systemic, causing controversy with the local actions in curative basis. The abscopal effect of low intensity ionizing radiation is well-known. Our objective is to show the abscopal effect with local non-ionizing radiation, action on blocking the invasion of cells to the blood-stream and together with immune-stimuli extends the local method to systemic therapy. Method Non-ionizing modulated RF radiation (mEHT, trade name: oncothermia) is used. This technology is impedance controlled capacitive coupling with amplitude modulation by the time-fractal pattern. mEHT selectively targets the rafts of transmembrane proteins on the cell membrane of malignant cells. The nano-selection is based on the certain deviations of metabolic-processes which enriches the ionic species in the extracellular electrolyte increasing the local conductivity and guiding the RF-flow. The missing or rearranged cellular organizing pattern of malignant cells also makes the selection of the irregular cells possible. Finally the cell-killing energy absorption is connected to the beta and delta absorption in the cell-membranes. There were various in-vitro and in-vivo immune-histochemical studies proving this selection and its effects. Results Significant tumor-cell death shown by TUNEL caused by mEHT. Mitochondrial Bax and release of Cytochrome C and nuclear translocation of apoptosis inducing factor AIF are measured [3]. Immunohistochemistry and apoptosis protein array proved elevated hsp70 and hsp90 expression and released them from the cell. Earlier cytoplasmic to cell membrane exposure of calreticulin and later release of HMGB1 protein from cell nuclei were observed. The set of molecules in the measured apoptotic processes form damage associated molecular pattern (DAMP) concluding to immunogenic cell-death (ICD) [4]. The abscopal effect is proven by the in-vivo experiment using an intratumoral dendritic cell (DC) injection together with the mEHT for C3H/He mice inoculated with tumor in femoral region. The non-treated tumor in the abdomen was measured. The whole body antitumor effects are proven, [5]. Furthermore, mEHT plus DC administration significantly inhibits the CT26 tumor growth in BALB/c mice, while even the re-challenging of the tumor inoculation became impossible, [6]. In this case the abscopal effect works like vaccination. The combined mEHT-DC treatment increases the leucocytes and macrophages with increased eosinophils, organizing specific T-cell response. Together with the experimental research level multiple clinical results show the efficacy of the method and feasibility of the new abscopal approach. The method is combined with most of the major oncotherapies. The main observable indicators of the results are the elongation of the survival time and at the same time improvement the quality of life. There are case-reports, Phase I and Phase II trials that approve the promising technique, including lesions: Bone (metastatic); Breast; Colorectal; Gliomas; Head & neck; Brain (metastatic), Kidney; Liver (metastatic and primary); Lung (NSCLC, and SCLC); Pancreas; Cervix; Ovary; Prostate; Soft-tissue sarcoma; Stomach; Urinary-bladder; Uterus. Conclusion Method of mEHT induces tumor cell apoptosis and enhances the release of Hsp70, unlike conventional hyperthermia. The consequence of the selective heating of the membrane rafts induces DAMP and ICD. mEHT can create a favorable tumor microenvironment for an immunological chain reaction that improves the success rate of intratumoral DC immunotherapy inducing abscopal effect by tumor specific immune reaction. The main medical advantages of the method are its personalized targeting together with the effective selection and distortion of the malignant cells. The new direction of application focuses on the blocking of their dissemination, as well as promoting the bystander (abscopal) effect acting on far distant metastases by local treatment. The method is successfully developed in the direction of the immune-support, pointing an exciting area: cancer-vaccination. These effects are well indicated in clinical practice but due to the proper funding the Phase III clinical trial is missing yet. For further development of the method the Phase III clinical trial is warranted.
        Speaker: Oliver Szasz (St. Istvan University, Biotechnics Department)
    • Wednesday afternoon - Poster Presentations - Screen5
      Convener: Mr Oleg Belyakov (IAEA)
      • 207
        Electrometers intercomparison using ionization chamber and radioactive check source
        Introduction Radiophysics department of the Institute of Oncology Ljubljana, use different electrometers for absolute dosimetry. They are from two different vendors PTW Freiburg GmbH and IBA Dosimetry GmbH. Intercomparison study was carried out in which a total of nine electrometers were compared by using a radioactive check source. An electrometer used by the Institute of Occupational Safety was used as a reference as the institute is approved by national authority to perform external dosimetry audits in the field of radiotherapy. Materials and methods In the study we used five electrometers from PTW (2 PTW Unidos and 3 PTW UnidosWebline) and four from IBA Dosimetry (3 IBA Dose1 and 1 IBA Dose2) (figure 1). The 0.6 cm3 Farmer type chamber (PTW 30013) was inserted in a Sr-90 radioactive check device (PTW T48012-0444) with an activity of 33 MBq from 15/2/2010. The chamber was connected with a triaxial extension cable to the electrometer. Collected charge at bias voltage +400V for the time of 180 s was measured. The ambient temperature and air pressure were monitored during the measurements to be able to correct the results. With each electrometer we carried out 3 measurements to ensure the stability as well as to minimize the statistic error. Results From the results in the table 1 we can see that the PTW electrometers collected charge is positive while for IBA electrometers charge is negative, even though the voltage was set to +400V. The reasons for these discrepancies are the differences in conventions expressing the polarity of the voltage of the two manufactures. In IBA electrometers a central electrode of the chamber is positive when you apply +400V while for the PTW electrometers central electrode is charged to -400V. Discovering this difference the measurements were repeated in a physically correct way. The repeated results as well as the difference regarding to the electrometer of the Institute of Occupational Safety are shown in the table 1. During the measurements the temperature and the pressure were stable therefore no correction was necessary. Conclusion This study showed an excellent agreement between the electrometers for the same vendor and series. As we could expect, there is a minor difference between the manufactures which is very low and can be neglected. We have to emphasize in the results we did not consider the uncertainty of the measurements. However we discovered that the oldest electrometers (PTW Unidos) used in our test had the largest difference to a reference and a manufacture recalibration should be considered. Unfortunately the manufactures do not use the same convention for the definition of the polarity of central electrode which can lead to larger discrepancies when measuring the absolute dose.
        Speaker: Attila SARVARI (Institute of Oncology Ljubljana)
      • 208
        Low dose-rate prostate brachytherapy: do different seeds manufacturers matters?
        Introduction: Prostate cancer is the most common cancer in males, excluding non-melanoma skin cancers. Clinical presentation is variable and the disease is classified as having low, intermediate or high-risk. The main modalities of treatment are radical prostatectomy (RP), brachytherapy (BT), and external beam radiation therapy (EBRT), with or without androgen deprivation. Brachytherapy is a treatment option with the same efficacy as EBRT or RP alone in patients with newly diagnosed low- or intermediate-risk prostate. In Brazil, there are few centers (23) performing low dose rate (LDR) BT, using about 25,000 seeds/year. We started our program at the Hospital Sírio-Libanês (HSL) in 1998 and currently we have already treated 1043 patients with LDR BT. The source description in the planning system has an important role for the treatment, because the source geometries, including encapsulation and internal structure leads us to use different parameters of dose rate constants, radial dose and anisotropy functions. AAPM Recommendations Regarding Clinical calibration of seeds, ask for calibration of at least 10% of the seeds prior to the implant, for every implant. Clinical calibration agreement with manufacturer should be within 3% of batch mean and 5% maximum deviation from mean. For the past 18 years, this was the procedure at HSL using the OncoSeed® 6711, produced by Amersham using Well Chamber (Standard Imaging HDr Plus) with calibration factor for 6711 seeds model. In March 2016, after a government motion, all the centers performing LDR BT started to use Best® seeds model 2301, for the first time in the country. When performing the clinical calibration of this new seed, a difference of 17%, between the certificated one and our measurement was observed. At this time we were using the same dosimetry system. In Brazil there is no Accredited Laboratory and no possibility to obtain the calibration factor for Iodine-125 seeds Best model 2301. In addition, the dose calculations for treatment were generated by the Variseed® treatment planning system (TPS) using the parameters of the two sources and the dose distribution was different between them. The objectives of this study were to determine the correct calibration factor of our well chamber for the Best 2301 seeds and to determine the clinical source calibration of these seeds; to evaluate the interchangeability of the two commercially available 125I sources by assessing the dosimetric effect in the implant dose distribution and how this affects our daily practice. Methodology: Three sources with different activities : 0.502 mCi , 1.001 mCi . and 1.194 mCi were sent to Instituto de Pesquisas Energéticas e Nucleares (IPEN) by Best Company. The seeds were calibrated by National Institute of Standards and Technology (NIST). With the known sources activities, we performed cross-calibration measurements and the new calibration factor was set for our well chamber. Calculations using the available sources geometries, radial dose functions and anisotropy distributions were performed with both manufacturers’ seeds and the results were compared. The Variseed TPS was used for calculations. Results: The dose-volume histogram generated for each manufacturer showed marked differences mainly in the high-dose regions. The measured difference in the calibration for the two sources was 17%. Using this new factor, a difference of only 1 to 3% between the certified value and our calibration was observed. When comparing the dose distribution in the volume receiving 100% of the prescribed dose, differences of up to 10% mainly in the high dose region within the implant were observed.The reason of this can be explained by source geometries differences, including encapsulation and internal structure leads to different parameters of dose rate constants, radial dose and anisotropy functions . Conclusions: Chamber calibration factor for the specific manufacturer is necessary for the clinical source calibration and In the absence of an Accredited Laboratory , like in Brazil, the cross-calibration measurements is a reasonable solution. The dose distribution for two source designs presented important differences mainly in the volume within the internal high-dose regions and may affect the dose received by non-target internal sites . A simple interchangeability of sources from different manufacturers is not recommended without the appropriate clinical calibration and dosimetric evaluation.
        Speaker: Cecilia Maria Kalil Haddad (Sirio Libanes Hospital)
      • 209
        Audit of VMAT delivery techniques in the Baltic States
        Purpose: To evaluate VMAT planning and dosimetric delivery accuracy in the Baltic States through on site visits with the PTW Octavius 4D 1500 system. Methods: The data (CT images with contours in DICOM RT format) for three patients (prostate, pelvic nodes, head & neck) was send to participants to be planned on local Treatment Planning System (TPS). The target dose objectives and critical organ dose constrains were specified in the planning instructions. The verification plans for 3 cases were created for PTW Octavius 4D phantom. During on site visit the prepared treatment plans were reviewed and measured with PTW Octavius 4D 1500 system which was brought in to each site and results were analyzed using PTW Verisoft 6.1 software using 3D gamma method with 3% (local and global dose) and 3 mm criteria. 6MV beam from Varian linacs was used in all centers and Varian Eclipse TPS was used in 3 centers and Elekta Monaco TPS was used in one center. Results: The audit was carried out in 4 hospitals that performed VMAT during 2015. The audit measurements took approximately 4-5 hours in each hospital and were performed after clinical work. The gamma pass-rates are shown at Figure 1. Conclusion: The audit showed acceptable dose distribution results for the implementation of VMAT delivery in the visited centers. It has also showed the feasibility of using commercial 2D array with the phantom for on-site visit types of audit.
        Speaker: Eduard Gershkevitsh (North Estonia Medical Centre)
      • 210
        Establishment of National Radiotherapy audit program at NMISA.
        **Introduction** Morden radiotherapy treatment of cancer involves different modalities. Some of these modalities have limited number of referral literatures. These modalities include advanced treatment like IMRT, Stereotactic, RapidArc, Gamma knife etc. Radiotherapy dosimetry audits play an important role in verifying the treatment chain of all these techniques. The National Metrology Institute of South Africa (NMISA) has embarked on establishing a national audit programme for radiotherapy. Five pilot centres were identified for performing on site audit measurements with procedures and protocols drafted and tested during measurements. For postal dosimetry audits, a Dose Ace system using radiophotoluminescent (RPL) glass dosimeters has been purchased by NMISA. This system will replace the Thermoluminescent dosimetry (TLD) system currently used by IAEA/WHO for audits. **Methodology** On site Audit measurements were carried out for reference conditions, non-reference conditions and end to end using a CIRS phantom. For reference conditions, the IAEA TRS 398 protocol for absorbed dose to water was followed. Measurement were carried out using a Farmer type chamber for photons and an Advanced Markus chamber for electrons. A water phantom was used for photon beam measurements and a Perspex phantom for electron. Non-reference measurements were carried out for Wedge factors and Output factors. The auditing procedure for end to end entailed using a CIRS thorax phantom. The phantom was scanned using a CT scanner on site and data transferred to the treatment planning system (TPS) for verification. The planning staff were requested to create a plan per procedure provided and plan was transferred to treatment system upon completion. Staff members responsible for treatment were requested to execute the plan using the CIRS phantom. Farmer type ionization chamber was placed on different positions and the delivered dose was measured and compared with measured dose from TPS. **Results** The action limits for reference conditions was 2% and for non-reference conditions it was 3%. For reference conditions measured doses were within 2% and for end to end dosimetry audit the maximum deviation was observed on areas with low electron density. However total contribution to a selected reference point was within 5% for most pilot centres. Commissioning of the RPL glass dosimeter system is still an ongoing project and the results will be presented in the conference. **Conclusions** The establishment of onsite dose audit methodology for radiotherapy centres in South Africa using the ionization chamber was successful. All protocols were drafted and tested for consistency and reproducibility. Some of the challenges encountered during pilot study was the breakdown of the units, unwilling cooperation from some staff members and less understanding of the objectives of dosimetry audit by some staff members. A steering committee consisting of representatives from Oncologists, Radiation Therapists, Medical Physicists and regulatory has been formed. They regularly meet to discuss the progress for the establishment of the project and evaluate the procedures. They will also be responsible for any unresolved discrepancies in measurement results.
        Speaker: Humbulani Vincent Maselesele
      • 211
        Image comparison of 3 different known geometrical shapes contoured on different imaging modalities on a phantom for stereotactic frameless procedure of AVM
        Objective: To compare the accuracy of 3 different known geometry objects drawn on CT (Computed tomography), MR (Magnetic Resonance) and DSA (Digital subtraction Angiography) images on a phantom with stereotactic frameless mask on Brainlab iPlan RT Image contouring workstation. Methods and material: A phantom study was done for images registration and contouring accuracy for SRS case of Arterio-Venous Malformation (AVM) treatment. Phantom was designed in such a way that it contains 3 different shapes; 1. Spherical plastic ball filled with water, 2. Egg shaped (ellipsoidal) gel ball, 3. Irregular electron p-orbital shaped (px, py, pz) structure made with olive oil capsule. All three different shapes material were chosen in such a way that all contains hydrogenous material which could be imaged in MR machine and at the same time DSA and CT images could also be acquired of the same material. DSA images were taken with two standard anterio-posterior and lateral pair. CT was taken with 1 mm slice thickness in Philips CT scanner, and MR was taken in sagittal section with 3 Tesla MRI machine (Philips). All images were imported in iPlan RT image (v 4.1.1) contouring workstation. CT images were localised using Brainlab head and neck localiser, afterward standard x-Ray pair were imported, localised with CT-Angio localiser and at last MR images were imported, fused with CT images. All the three imaging modalities CT, MR and x-Ray pair were fused and localised. Thus, contouring on any imaging modalities would reflect on other modalities also. All different objects were contoured independently on MRI, CT and DSA and their volumes were measured and noted. Afterward intersecting volumes between all three structures were measured by creating intersecting objects between images over all the 3 imaging modalities (CT, MRI and DSA). So total 9 single objects images and 9 intersecting images were generated and their volumes were calculated. The intersection volumes denoted the accuracy between two different imaging modalities that two volumes look like similar on both. Result: It was found that standard x-Ray pair could not form irregular images, they were good for spherical and ellipsoidal objects but for irregular tumor they were providing only outer boundaries and the actual tumor could be drawn on 3-dimensional set of images obtained from MR and CT. The volume of spherical ball in CT, MR and DSA image were 37.4 cc, 30.9 cc, 32.9 cc respectively and the volumes of ellipsoidal ball were 62.4 cc, 57.2 cc, 51.6 cc respectively and volume of p-shaped orbital structure were 5.9 cc, 3.2 cc and 6.6 cc respectively. The intersection volumes between MR and CT for ellipsoidal, spherical and p-orbital shape were 56.8 cc, 30.7 cc, and 2.5 cc respectively. The intersection volume for MR and DSA images for ellipsoidal, spherical and p-orbital shape were 49.7 cc, 30.4 cc, 2.1 cc respectively. The intersection volume in CT and DSA for ellipsoidal, spherical and p-orbital shape was 51.4 cc, 32.9 cc, 3.7 cc respectively. Conclusion: The study concluded that for contouring of irregular tumor on DSA will not give the precise picture of tumor, although it can provide an envelope around tumour which can further be contoured on MRI and CT imaging modalities more accurately.
        Speaker: Tharmar Ganesh (Fortis Memorial Research Institute Gurgaon Haryana)
      • 212
        Clinical implementation from the regional (AFRA) training course on quality assurance of record and verify systems
        In equipping clinical medical physicists across the African Member States with both theoretical and practical information on the quality assurance (QA) procedure of records and verify systems (R&VSs), the International Atomic Energy Agency (IAEA) organized a regional (AFRA) training course. The main focus of the course was to equip participants to validate data integrity that will be followed for patients from the time of finalizing a treatment plan until just before and during treatment. The participants from Ghana and Kenya with similar radiotherapy setup carried out a joint comprehensive R&VS QA and an end-to-end test (i.e. from TPS to R&VS) after the course. A CIRS thorax phantom was CT scanned head first supine and imported into Oncentra MasterPlan Treatment Planning System (TPS). 3D treatment plans were generated to include different fields to test all relevant geometric settings of the treatment unit that are applied clinically. The approved plans were exported from the TPS and imported into MosaiQ R&VS. The plans were then transferred unto the Linac treatment console and treatment fields set up and checked. These checks were classified as general (demographic), geometric and dosimetric, and dose delivered error sections. The transfer of fundamental treatment parameters (e.g. energy, gantry angle, collimator angle, couch angle, field size, wedge, MU) were manually checked by comparing the data in the R&VS with TPS printouts prior to the treatment. The light field (e.g. X and Y jaws and MLC) pattern on the treatment unit was verified against printouts of the light field projection generated in the TPS. From a total of 30 items checked with the end-to-end test, no mismatch between treatment planning system data and R&VS data were observed. For the R&VS QA, out of a total of 34 tests conducted, the relative discrepancies of items checked were 8.5% in the general section, 13.3% in the geometric and dosimetric section, and 4.9% in the dose delivered section. There was a high data integrity observed for the end-to-end test between the TPS and R&VS due to the two systems sharing a single DICOM database. The observed discrepancies in the QA test points out the system’s inability to totally eradicate all errors, hence extra vigilance on the part of radiotherapists and medical physicists. These QAs and tests contributed to achieving a better understanding of the system and helped resolved issues related to its data integrity.
        Speaker: George Felix Acquah (Sweden Ghana Medical Centre)
    • Session 14a - Imaging for planning and treatment delivery in External Beam Radiotherapy - Part 2

      Learning objectives:
      1. To learn about the imaging modalities available for planning and treatment delivery

      Conveners: Mr Brendan Healy (International Atomic Energy Agency) , Prof. Dietmar Georg (Medical University of Vienna) , Dr Rajiv Prasad (IAEA)
      • 213
        PET-CT for radiotherapy planning in lung cancer: current recommendations and future directions
        Speaker: Mr Gerard Hanna
      • 214
        The role of the radiation therapist (RTT) in image guided radiotherapy (IGRT)
        Speaker: Ms Michelle Leech
      • 215
        Image registration methodology to quantify ROIS’ volume transform accuracy
        *Introduction*Medical images registration is the process of superimposing two or more images of the same scene taken at different times, from different points of view, and / or by different sensors. This geometrically aligns two images, the reference one and the detected (mobile) image. In radiotherapy, the clinical evaluation of a treatment plan is performed by various methods, such as image analysis or patient's clinical condition, among others. At the Radiotherapy Department of Hospital Oncologico Cordoba - Argentina, a rather recurrent problem is a noticeable change in patient's anatomy during the normal course of his radiant treatment. This situation requires a new CT scan to go through a second or third stage in the treatment planning. Consequently, there are differences between the sets of tomographic images captured at different moments due to the discrepancies in conditions of imaging, either because of difficulties in reproducing the original positioning of the patient or because of the obvious change in some of its structures. Image registration plays a fundamental role in all medical image analysis tasks. From the TPS it is possible carry out a visual analysis of the images, and in some cases the volumes of the regions of interest (ROIs), structures that are linked to the tomography, are observed. This analysis is subjective and qualitative compared to the treatment planning topographies’. Then, three goals are to be achieved: 1. to obtain suitable reference frames to merge tomographic images obtained in different stages and / or positions; 2. to find a correlation between the volumes of organs at risk from both sets of tomographic images through the use of co-registration and image fusion methods; 3. to obtain a systematized tool that allows to make this comparison of volumes involved.*Materials and methods* This work was carried out using a computer-based tool of free accessibility, known as 3D-Slicer, which is able to perform co-registrations by different methods: for instance, Mutual Information, co-registration based on structures delineated by the physician, or Self-segmentation, fiducial registration, Landmarks, etc. Thus, an analysis of the recorded images and their delineated structures (ROIs) is obtained. Then, by calculating the percentage error in structures’ volume of organs at risk (EV%), it is possible to quantify the discrepancies committed in the delineation of the structures of interest between tomographic images with and without registration. The transformation after registration is considered to induce deformation, but not a change in the volume of structures of organs at risk. In addition it is possible to quantify the change in the volume of ROIs generated by the transformations after the registration has been applied.*Results*Some image registration algorithms are sensitive to the deformations induced by the applied transformations, such as the General Registration (BRAINS), semi-automatic register and Affin Transformation, which were discarded for being unreliable. The search for a systematized co-registration tool capable to quantify errors leads us to answer the questions raised in each objective proposed, and the use of the Fiducial Registry and the EV% calculation method to quantify the accuracy of the registry and its precision, respectively. A measure of quantification in the co-registration of medical images was obtained using the structures related to the tomography as reference frame. Analyzing its deformation and its volume change after the registration, an accuracy assessment was obtained by means of the RMS error provided by the fiducial record, which gives us an idea of exactly how the method used, by the strategic location of Landmarks on bone or anatomical landmarks at tomography. Using the EV% calculation method as a versatile and simple tool for the quantification of the accuracy of the registration process and its transformation, it is possible to contrast the results obtained in unexpected volume changes (ROIs) in the transformations, and also in the selection of the chosen registry: Fiducial and Surface Registration (with Rigid and Similarity transformations).*Conclusions* It was possible to obtain the reference’ frames and quantify the accuracy of the probable measurement as well as the precision of a registration algorithm and its transformations, from the study of structures of organs at risk. The results obtained could open the way of subsequent analyzes linked to Dose Volume Histograms (DVH), dosimetric validation by measurements and the use of other software to verify the reproducibility of the results.
        Speaker: Graciela R. VELEZ (Hospital Oncologico Cordoba)
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        Feasibility of prompt gamma imaging for passive-scatter proton radiotherapy treatments
        During proton beam radiotherapy, an ideal treatment plan has all the primary protons stopping at the edge of the tumour volume. Due to the sharp fall-off at the end of the Bragg peak, an in-vivo verification of the delivered dose has become a priority to ensure minimal radiation damage to the normal tissue surrounding the tumour and to ensure uniform dose deposition within the tumour. However, there are no primary particles exiting the patient to be used to develop an imaging device for in-vivo treatment verification. An alternate option is to use secondary radiation, like the prompt gammas produced by proton-nuclei inelastic collisions. Several detector designs have been proposed that use prompt gammas produced within the patient. These prompt gamma emissions mainly depend on the clinical proton energy and the atomic composition of the tissue, producing a wide energy range of possible gammas. For passive-scatter proton therapy, there is the additional challenge of extensive background radiation from the passive-scatter beam. The primary aim of this work is to investigate the feasibility of prompt gamma imaging in the passive-scattering proton therapy context, specifically for high-dose, low-fraction treatments, using a Monte Carlo simulation method with the Geant4 (v9.6.04) radiation transport code. The initial experiment measurements for this work were carried out at the proton therapy facility at iThemba LABS in Cape Town, South Africa. Detection of the prompt gammas produced by a 200 MeV passively scattered proton beam was performed with a LaBr3 detector surrounded by lead shielding. The detected prompt gamma energy spectra emitted from the water target is shown in Figure 1(a). This measurement looked at the discrete prompt gammas emitted from the dominant element $^{16}O$ found in water. The 6.13 MeV gamma-ray emission line with its first and second escape peaks is clearly visible as well as the emission line at 4.44 MeV due to the $^{16}O(p, \alpha)^{12}C^*$ reaction. A Monte Carlo model for iThemba passive-scatter proton treatment nozzle was built for comparison to the above-mentioned prompt gamma measurements. The model was validated using experimental depth and lateral dose data for clinical dose delivery. The Precompound model was selected for proton inelastic nuclear reaction and optimised against available experimental cross section data$^1$. The water target, the LaBr$_3$ detector and the lead shielding was added to the Geant4 beamline simulation to replicate the experimental results, shown in Figure 1(b). While the Monte Carlo model under-estimates the background radiation, the relevant prompt gamma peaks are clearly visible and provide a good validation for the Geant4 simulation. This prompt gamma Geant4 model was then used to evaluate the prompt gamma production from a typical brain arteriovenous malformation (BVM) treatment. A typical BVM treatment at iThemba LABS delivers 54.5 Gy over 3 fractions to a 5 x 4 cm cylindrical volume using a 10-cm water equivalent proton beam. Unfortunately, ethical clearance has not yet been granted to use patient data, so a simple model of bone, water, and tissue was used to mimic a patient. The prompt gamma production from several single-material targets (bone, water, tissue, lung, fat) was also simulated. These results will be discussed as well as the feasibility and the challenges of PGI for a passive-scatter proton therapy treatment. Figure 1: (a) Detected prompt gamma energy spectra (b) Comparison between measured and simulated energy spectra emitted from water target for proton energy corresponding to a 24-cm range in water. [1] Jeyasingam Jeyasugiththan and Stephen W Peterson "Evaluation of proton inelastic reaction models in Geant4 for prompt gamma production during proton radiotherapy" 2015 Physics in Medicine & Biology 60, 7617–7635.
        Speaker: Jeyasingam Jeyasugiththan (Department of Nuclear Science, University of Colombo)
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        Digital portal imaging in Cobalt-60 radiation therapy
        Introduction: Prior to the introduction of on-board kilovoltage X-ray imaging, portal imaging (that is, radiographic imaging with the megavoltage (MV) treatment beam) was the most effective way to verify the patient’s position for external beam radiation therapy. Portal imaging began with film based detectors and evolved to digital detectors known commonly as electronic portal imaging detectors (EPIDs). While the use of EPID based portal imaging has diminished somewhat in modern radiotherapy delivered on kV imaging equipped linear accelerators, MV portal imaging continues to play an important role since it directly relates the treatment beam geometry to the patient boney anatomy. Cobalt-60 (Co-60) therapy machines (which are still in widespread use in many parts of the world, due to their simplicity, reliability and relatively low cost) are generally not equipped for digital portal imaging. In this work, we show that the Co 60 unit’s large source size and high energy are not insurmountable obstacles to effective digital portal imaging. An amorphous silicon EPID whose output is sharpened and histogram-equalized, produces Co 60 digital portal images that clearly show the necessary bony anatomy in the pelvic, thoracic and cranial regions. These results suggest a simple EPID-based workflow for treatment verification that is compatible with conventional x-ray simulation for treatment planning. Methods: The experimental setup comprised of a Theratron 780C cobalt-60 irradiator (BEST Theratonics, Kanata, ON) equipped with amorphous silicon EPIDs mounted on a free-standing cart. The EPID was either a XRD1640 panel (Perkin Elmer Optoelectronics, Fremont, CA) or an aSi500 unit (Varian Medical Systems Palo Alto, CA). The phantoms to be imaged were mounted on a 3-axis computer controlled positioning stage. The phantom and the panel were positioned at various source to axis/source to detector distances to investigate effects of imaging geometry. Specifically, SAD/SDD was set at 80/100, 80/120, 100/125 and 100/140 (dimensions in cm). The frame integration time for EPID acquisition was 133ms for the XRD1640 experiments (100ms for aSi500 runs) and 4 frames were averaged for each image. The phantoms imaged were the anthropomorphic CIRS 801-P pelvis (CIRS, Norfolk, VA) and SBU-4 (Kyoto Scientific Specimens). These phantoms are designed to be representative of natural human anatomy. Raw images from the EPID required post-processing to yield viewable images of acceptable quality. Image processing was done using in-house software written in MATLAB (Mathworks, Natick, MA). Global contrast adjustments (window and level) were found to be important, but not always sufficient, for extracting useful images from the raw EPID data. Additional techniques, such as iterative deconvolution and contrast-limited adaptive histogram equalization (CLAHE) were used to enhance images. For comparison, some images were also taken on a Varian 6MV linear accelerator with a built-in aSi500 panel. Results: Qualitatively, it was found that the post-processed Co-60 images were comparable to the ones obtained with the 6MV portal imager and that they are sufficient to identify bony anatomy. Deconvolution sharpening increased image quality as determined by measured point spread functions. CLAHE processing improved local contrast, thus overcoming the two main disadvantages one would expect of imaging using the Co 60 source. Conclusions: These results suggest that portal imaging in the treatment beam of a cobalt 60 unit, using modern amorphous silicon EPIDs, is possible and potentially useful. With some post-processing to enhance sharpness and contrast, the image quality achievable with the Co-60 system approaches that of a 6 MV linear accelerator’s portal imager, and is adequate to identify key parts of the bony anatomy relative to the treatment beam. It is not necessary to have a fully integrated, gantry-mounted EPID system to achieve some of the benefits of portal imaging. An independent EPID mounted on a mobile stand would be sufficient to produce portal images and double-exposure fields like those shown here. The only electrical interface required between the EPID and the Co-60 unit would be a source-out synchronization pulse.
        Speaker: L. John Schreiner (Cancer Centre of Southeastern Ontario at KGH)
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        Discussion, Q&A
    • Session 14b - The Role of professional societies and international organizations - 2
      Conveners: Mr Alfredo Polo (IAEA) , Prof. Jacob Van Dyk (Departments of Oncology and Medical Biophysics, Western University, London, Ontario, Canada)
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        Speaker: Mr Norman Coleman
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        Speaker: Mr Rengaswamy Sankaranarayanan
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        ESTRO (Physics)
        Speaker: Ms Nuria Jornet
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        Speaker: Prof. M. Saiful Huq (UPMC CancerCenter)
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        Speaker: Prof. Tomas Kron (Peter MacCallum Cancer Centre)
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        Speaker: Mr Kin Yin Cheung
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        Speaker: Mr Stefano Gianolini
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        Speaker: Prof. Jacob Van Dyk (Departments of Oncology and Medical Biophysics, Western University, London, Ontario, Canada)
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        Speaker: Mr FRANCIS HASFORD (Ghana Atomic Energy Commission)
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        Speaker: Mr Rodolfo Alfonso Laguardia
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        Questions and answers