Name: International Symposium on Trends in Radiopharmaceuticals (ISTR-2019)
Start: 2019-10-28T08:00:00+01:00
End: 2019-11-01T18:00:00+01:00
Location: Vienna International Centre

International Symposium on Trends in Radiopharmaceuticals (ISTR-2019)

from Monday, 28 October 2019 (08:00) to Friday, 1 November 2019 (18:00)

Monday, 28 October 2019

08:00

08:00 - 09:30
Room: Foyer

09:30

09:30 - 10:30
Room: M1

10:30 Coffee Break
Coffee Break
10:30 - 11:00
Room: Foyer
11:00 Production of medical radioisotopes: Research Reactor
Production of medical radioisotopes: Research Reactor
11:00 - 12:30
Room: M1
Contributions

11:00 M. Venkatesh: Production of reactor based radioisotopes: An international portfolio (IS) - Meera Venkatesh

11:25 R. Mikolajczak: Production and supply of medical radioisotopes: A Polish experience (IS)

11:45 Selective separation of no carrier added 47Sc from reactor irradiated Ca using zirconium vanadate gel for nuclear medical applications (9) - Mohamed Gizawy (Lecturer at Radioisotopes Production Facility (RPF), Egyptian Second Research Reactor (ETRR-2), Egyptian Atomic Energy Authority (EAEA), Cairo, Egypt)

12:00 Synthesis and neutron activation of Lu2O3 nanoparticles functionalized with target specific peptides - Guillermina Ferro-Flores

12:15 Towards a robust supply chain for medical radioisotopes - Titus Tielens (PALLAS)
12:30 Lunch Break
Lunch Break
12:30 - 14:00
14:00 Production of medical radioisotopes: Accelerators
Production of medical radioisotopes: Accelerators
14:00 - 15:35
Room: M1
Contributions

14:00 S.M. Qaim: Accelerator based production of non-conventional positron emitters and therapeutic radionuclides (IS)

14:25 S. Lapi: Production of radiometals using medical cyclotron (IS)

14:45 A. Abrunhosa: Application and development of liquid targets for PET radiopharmacy (IS)

15:05 J.Hoon Park: Radioisotope production and development with 30MeV cyclotron (IS)

15:20 V. Radchenko: Production and application of 225Ac/213Bi: TRIUMF experience and perspectives (IS)
15:30 Coffee Break
Coffee Break
15:30 - 16:00
16:00 Production of medical radioisotopes: Generators
Production of medical radioisotopes: Generators
16:00 - 17:30
Room: M1
Contributions

16:00 C. Cutler: Supply of 99Mo: Focus on US

16:20 B. Zhujkov: Successes and problems in the development of radioisotope generators

16:40 J. Harvey: Production of 99Mo: North Star projects

17:00 J. Osso: Role of the IAEA on the supply of 99Mo

17:15 Safeguards on the production of medical radioisotopes
18:00 Welcome Reception
Welcome Reception
18:00 - 19:30
19:45 Test A - Vojna ngjeqari
Test A
- Vojna ngjeqari
19:45 - 20:00
test abstract for acceptance
Tuesday, 29 October 2019
09:00 Production of radiopharmaceuticals: PET
Production of radiopharmaceuticals: PET
09:00 - 10:30
Room: M1
Contributions

09:00 J. Lewis: Development and application of monoclonal antibody based radiopharmaceuticals (IS)

09:25 C. Decristoforo: Theranostic Radiopharmacy (IS)

09:45 Innovative medical radioisotopes for theranostic application, and how they are produced - Vadim Gadelshin (AG LARISSA, Institute of Physics, Johannes Gutenberg University Mainz (Germany))

10:00 Preparation and Preclinical Evaluation of 64Cu-NOTA-anti MUC1 as a Radioimmunoconjugate for Diagnosis of MUC1+ breast cancer by PET - Behrouz Alirezapour (Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, IRAN)

10:15 Development of a new prostate cancer theranostic radiopharmaceutical - Laura Melendez-Alafort (Veneto Institute of Oncology IOV-IRCCS)
10:30 Coffee Break
Coffee Break
10:30 - 11:00
Room: Foyer
11:00 Production of radiopharmaceuticals: SPECT
Production of radiopharmaceuticals: SPECT
11:00 - 12:30
Contributions

11:00 A. Duatti: Revisting 99mTc Radiopharmaceuticals with recent advances in chemistry & imaging tools (IS)

11:25 G. Ferro-Flores: Production of radiolabelled peptides for SPECT-based theranostics (IS)

11:45 Radiopharmacy and growth of nuclear medicine in developing countries - Salah Bouyoucef (Department of nuclear medicine ) Amel Fellah (Nuclear medicine department )

12:00 Selective αvβ3 integrin detection using [99mTc(N)PNP43]-tagged RGDechi Peptides: synthesis and pharmacological studies - Cristina Bolzati (ICMATE-CNR)

12:15 The past, present and future trends in radiopharmaceuticals production in Brazil - Efrain Araujo Perini (Nuclear and Energy Research Institute (IPEN), Brazilian Nuclear Energy Commission (CNEN))
12:30 Lunch Break
Lunch Break
12:30 - 14:00

12:45 Ultra-High-Performance Synergistic PET, SPECT, Optical & X-ray CT for Preclinical Theranostic Research
Ultra-High-Performance Synergistic PET, SPECT, Optical & X-ray CT for Preclinical Theranostic Research
12:45 - 13:45

14:00 Poster Session Tuesday
Poster Session Tuesday
14:00 - 15:30
Room: M02

15:30 Coffee Break
Coffee Break
15:30 - 16:00
Room: M1
16:00 Production of radiopharmaceuticals: Therapy
Production of radiopharmaceuticals: Therapy
16:00 - 17:30
Room: M1
Contributions

16:00 M.R.A. Pillai: Production and quality control of beta emitters bone pain paliation agents (IS)

16:25 Comparison of promising new short range therapeutic radiopharmaceuticals using 225Ac, 213Bi and 161Tb - Zeevaart Jan Rijn (Necsa, Radiochemistry)

16:45 FREEZE-DRIED KIT FOR QUICK AND EFFICIENT PREPARATION OF 188ReN-DEDC/LIPIODOL IN HOSPITAL RADIOPHARMACY - Viju Chirayil (Bhabha Atomic Research Centre)

17:00 Production of Theranostic 153Samarium-labelled Polystyrene Microspheres for Hepatic Radioembolization - Chai Hong Yeong (Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia)

17:15 Radiolabeling and Pre-Clinical Evaluation of Y-90-DOTATATE - Formulated Using Y-90-Acetate from High Level Liquid Waste - Avik Chakrabotry (Radiation Medicine Centre, BARC, Mumbai, India)
18:00 Indian Permanent Mission
Indian Permanent Mission
18:00 - 19:30
Room: M1
21:15 IN VIVO STUDY OF RADIOLABELED FLAVONOID 99mTc-QUERCETIN AS CANCER RADIOTRACER ON NORMAL BALB/C MICE - eva maRIA widyasari (batan)
IN VIVO STUDY OF RADIOLABELED FLAVONOID 99mTc-QUERCETIN AS CANCER RADIOTRACER ON NORMAL BALB/C MICE
- eva maRIA widyasari (batan)
21:15 - 21:30
IN VIVO STUDY OF RADIOLABELED FLAVONOID 99mTc-QUERCETIN AS CANCER RADIOTRACER ON NORMAL BALB/C MICE Rizky Juwita Sugiharti, Eva Maria Widyasari, Maula Eka Sriyani, Iswahyudi, Iim Halimah, Endah Rosyidiyah, Ahmad Kurniawan Center for Applied Nuclear Science and Technology – National Nuclear Energy Agency Jl. Tamansari No 71, Bandung, West Java, Indonesia – 40132 Abstract [OBJECTIVE] Cancer is a major health problem and it is estimated that more than 10 million new cases of cancer diagnosed worldwide with more than 4 million deaths, annually. Chemotherapy is still the primary choice in cancer modality that uses chemotherapeutic drugs to eradicate and inhibit the growth of cancer cells. This treatment has excellent reliability and effective to kill cancer cell, but its cost is high. Therefore, patient tends to seek alternative treatment such as consuming traditional herbal medicine. Abundant presence of flavonoid in natural product used as traditional herbal medicines that have an interesting bioactivities needs to be studied. Quercetin (3,3ʹ,4ʹ,5,7-pentahydroxyl-flavone) is a flavonoid compound found in many fruits and vegetables that have antioxidant activity. As an antioxidant compound, quercetin will protect the body from free radical that can increase the risk of disease. However, as traditional herbal medicine, its effectiveness is not yet been fully established due to the lack of scientific information. Many in-vitro studies have proven the effectiveness of quercetin as an anticancer compound, but the data from in-vivo study is still limited. In recent years, several radioisotopes have been utilized for biodistribution studies of biologically important natural product because nuclear medicine techniques provide some advantages over conventionally used methods in term of detection sensitivity and availability. This study was conducted as a preliminary study to understand biodistribution pattern of 99mTc-quercetin on normal balb/c mice. In vivo data from this study would provide meaningful biological and pharmacological information of 99mTc-quercetin for understanding its effectiveness as for development of quercetin as anticancer agent. [METHODS] 99mTc-quercetin was prepared by addition of 30 µl (1 mg/ 1 mL) of solution SnCl2.2H2O into a glass vial containing 320 µL quercetin solution (0,5 mg/320 µL) and 200 µL 0.2 M phosphate buffer pH 7.5. pH of the mixture was adjusted to 7.5 by addition of NaOH 0,1 N and final volume of the mixture was carried out into 600 uL by addition of bidistilled water. Thereafter, 400µL (± 0,5 mCi) of freshly eluted 99mTcO4- was added into the vial and incubated within 5 minutes in room temperature. Radiochemical yield of 99mTc-quercetin was determined using thin layer chromatography using TLC-SG F254 strips with two solvent systems to distinguish and quantify the amounts of radioactive contaminants (free 99mTcO4, 99mTcO2). Chromatography system of TLC-SG F254 / acetone was used to separate impurities of 99mTcO2, while TLC-SG F254/NaCl 0.9 % was used to separate free 99mTcO4. Radioactivity on chromatograms strips was measured using TLC-scanner (AR-2000, BIOSCAN). Animal studies were conducted in accordance with our institutional guidelines and were approved by Ethics Committee for Care and Use of Experimental Animal - National Nuclear Energy Agency. Biodistribution studies were performed by intravenous administration of a 0.1 mL 99mTc-quercetin (2.6 μCi/100 μL) to 5-week-balb/C mice (BIOFARMA). Groups of three mice were used for the experiments. Organs of interest were removed, weighed, and the radioactivity was determined with an automatic-well γ counter (2470 Wizard, PERKIN ELMER) at 15 minutes, 1, 3, and 24 h post-injection. Urine and feces were collected for 24 h post injection, and the radioactivity counts were determined [RESULTS AND DISCUSSION]: Labeling efficiency of the 99mTc-quercetin was assessed by thin layer paper chromatography. In TLC-SG F254 using saline as the solvent, free 99mTc moved with the solvent front, while 99mTc-quercetin and 99mTcO2 remained at the spotting point. 99mTcO2 was determined by using TLC-SG F254 / acetone as the mobile phase where the 99mTcO2 at the point of spotting while free 99mTc and 99mTc-quercetin moved with the solvent front. The radiochromatogram of 99mTc-rutin was presented in Fig 1. and 2. 99mTc-quercetin had labelling efficiency > 90 % and can be used to carry out in vivo test. Figure 1. Chromatogram profile of 99mTc-quercetin and TcO4- with TLC-SG F254 /saline Figure 2. Chromatogram profile of 99mTc-quercetin and TcO2 with TLC-SG F254 /acetone Figure 3. Biodistribution study of 99mTc-quercetin Biodistribution study in normal mice showed that the radioactivity levels in the stomach were below 1%ID up to 24 h post-injection, indicating that 99mTc-quercetin was stable in vivo. The uptake of 99mTc-quercetin in kidney in 15 minutes was 6.13±1.05 %ID/g and remain 3.31±0.29 %ID/g at 24 hour post injection. After 15 minutes, 1 hour, 3 hour and 24 hour post injection the radioactivity levels on blood was 3.39±0.21 %ID/g, 1.81±0.54 %ID/g 1.59±0.30 %ID/g and 0.46±0.07 %ID/g respectively. These results suggested that 99mTc-quercetin had fast rate of plasma clearance after administration. The biodistribution study of 99mTc-quercetin also demonstrated that high radioactivity accumulation was found on liver at all post injection time points, indicating that 99mTc-quercetin was lipophilic compound. Moreover the radioactivity was observed in intestine for 15 minutes, 1 hour, and 3 hours that is 1.63±1.96 %ID/g, 1.53±0.33 %ID/g, and 1.44±0.53 %ID/g then the uptake value was decreased after 24 hours to 0.54±0.20 %ID/g. This study also showed that 99mTc-quercetin was excreted through urinary and fecal excretion. Those result in the current study demonstrated that intravenously injected of 99mTc-quercetin was metabolized in the liver and moved to intestine via the bile duct. [CONCLUSION] This study gave preliminary biodistribution data of 99mTc-quercetin in normal mice. Further studies on target accumulation of 99mTc-quercetin in animal model with cancer would provide a good basis for developing radiolabeled flavonoid as radiotracer to understand the mechanism of quercetin as anticancer. [REFERENCE] 1. Hosseinimehr, SJ., Ahmadi, A., & Taghvai, R.,2010, “Preparation and Biodistribution Study of Technetium-99m-labeled quercetin as a potential radical scavenging agent”. “J. Radioanal Nucl Chem”, 284 : 563 – 566. 2. F. Yurt Lambrecht, O. Yilmaz, E. Bayrak, G. Kocagozoglu, K. Durkan, 2010, “Could be radiolabeled flavonoid used to evaluate infection?”, J Radioanal Nucl Chem, 283:503–506 3. Sriyani, M. E., Utami, D. A., Widyasari, E. M., Marzuki, M., 2015, “Iodination Method of Quercetin for Synthesis of Anticancer Labelled Compound”. Elsevier. 16 (1): 245-250. 4. Qinghua Xie, Xia Li, Guangquan Wang, Xuan Hou, Yujun Wang, Hongbo Yu, Changfa Qu, Shunzhong Luo, Yali Cui, Chuanqin Xia, Ruibing Wang, 2017, “Preparation and evaluation of 131I-quercetin as a novel radiotherapy agent against differentiated thyroid cancer”, J Radioanal Nucl Chem, 1697–1708 5. Widyasari, E. M, Sriyani, M. E., Daruwati, I., Halimah, I, Nuraeni, W., 2019, PHYSICOCHEMICAL CHARACTERISTIC OF LABELED COMPOUND 99mTc-QUERCETIN.”Indonesian Journal of Nuclear Science and Technology”, 20 (1): 9-18 6. Widyasari, E. M, Simarmata, M.Y.A., Marzuki, M., Sriyani, M. E., Sugiharti, R.J., Nuraeni, W, 2019, PREPARATION OF 99mTc-QUERCETIN AS CANCER RADIOTRACER IN DRUG DISCOVERY, Rasayan J. Chem., 12(1), 278-283.
21:30 The critical parameters of Ga-68 labelling of POLATOM’s PSMA-11 kit. - Michal Maurin (National Centre for Nuclear Research, Radioisotope Centre POLATOM)
The critical parameters of Ga-68 labelling of POLATOM’s PSMA-11 kit.
- Michal Maurin (National Centre for Nuclear Research, Radioisotope Centre POLATOM)
21:30 - 21:45
Introduction. Development of the universal radiopharmaceutical kit, which would contain the active ingredient, i.e. PSMA-11 (nazwę chemiczną tutaj), and excipients allowing its efficient radiolabeling with 68Ga eluate regardless the type of 68Ge/68Ga generator used, remains a challenge. The aim of the study was to determine the critical quality parameters of our earlier y developed kit for 68Galabelling of PSMA-11 and the investigation of limitations in the radiolabelling conditions. Methods. The study was performed using sterile and endotoxin free dry kits, which have been developed in our lab, each containing 20 µg of PSMA-11 and 60 mg of sodium acetate. To investigate the labelling conditions (pH, radioactivity, volume) the kits were labelled with 68Ga eluted from the different 68Ge/68Ga generators (manufactured by ITG, Eckert&Ziegler and IRE) in volumes ranging from 1 to 5 ml and radioactivity from 200 MBq up to 1.2 GBq. The labelling yield and radiochemical purity were checked by HPLC (Kinetex C18 150mm; A: 0.1%TFA/H2O, B: 0.1%TFA/CAN, 5-50% B in 10 min) and TLC (ITLC SG; 10% NH4OAc/MeOH 50/50 v/v). In the second part of study the influence of potential metallic impurities originating in the 68Ge/68Ga generator eluate or other reagents were tested by spiking the labelling mixture with the Zn(II), Cu(II), Fe(III), Al(III), Ti(IV), Ge(IV) and Sn(IV) ions. The formation of the PSMA-11 metal complexes was confirmed by HPLC-MS. The stability of the kits was studied in lowered temperature (2-8°C), room temperature (25°C) and in transport conditions (at 35°C for two weeks). In the stability study, the main parameters controlled were the radiochemical purity of the labelled PSMA-11 and the radiolabelling yield after using low and high volumes of the eluate. Results and discussion. It was observed that 20 µg of PSMA-11 in the kit is sufficient to obtain high radiolabeling yield (>99%) even if high radioactivity of 68Ga eluate (> 1GBq) was used. Also, the varying volume of the radiolabeling does not affect the radiochemical yield. The most critical parameter of labelling is the pH, which should be maintained < 5. In the pH range of 4.5-5.0 the labelling yields were >98% or between 95 and 98%, depending on the batch, and the type of 68Ge/68Ga generator. These differences in the labelling yields could be attributed to to the presence of metallic impurities in the eluates. The collected stability data indicated that manufactured kits are very stable during storage at 25°C as well as at elevated temperature (up to 35°C).
21:45 111In-labelled bifunctional agents for dual targeting of breast cancer cells - Lurdes Gano (Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, )
111In-labelled bifunctional agents for dual targeting of breast cancer cells
- Lurdes Gano (Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, )
21:45 - 22:00
Background/Objective Breast cancer (BC) is the most common invasive cancer diagnosed in women worldwide. The estrogen receptor (ER) is a well-established biomarker for prognosis and guiding treatment of patients and is a good target for molecular imaging and radionuclide therapy. The objective of this study was to improve the theranostic value of previously studied 111In-labelled ER-targeting moieties (e.g. estradiol derivatives/LXXLL-based peptides) by enhancing the delivery of the radionuclide into BC cells’ nucleus in close proximity to DNA. To achieve that goal, we have explored an approach that combines into a single 111In-hybrid compound two different biological targeting moieties for dual targeting of BC cells. Hybrid compounds containing an ER ligand conjugated to a DOTA derivative functionalized with a nuclear-targeting moiety (DNA-intercalating agent, AO, or a peptidic nuclear localizing sequence, NLS) were synthesized. The bifunctional compounds were radiolabelled with the Auger electron emitter Indium-111 that has simultaneous emission of gamma radiation aiming the selective delivery into ER+ breast cancer cells. Methodology Synthesis of a DOTA- based prochelator that can allow double vectorization with two different molecular entities was achieved by following an orthogonal strategy. The versatility of this chelator to prepare radiolabelled hybrid compounds was demonstrated by the synthesis of three different conjugates containing an ER-binding molecule and a nuclear-targeting agent. Radiolabelling with 111In was performed at 95ºC, pH=5 acetate buffer. Radiochemical purity and in vitro stability of the radiolabelled compound was evaluated by HPLC. Cellular uptake of 111In-conjugates was assessed in MCF-7 (ER+) and MDA-MB-231 (ER-) human BC cells. The subcellular localization, in particular the internalization into the cell nucleus was also evaluated. The ability of 111In-compounds to induce DNA damage in vitro was tested by incubation with double-stranded plasmid DNA for 140 hours. Biodistribution was assessed in female mice with MCF-7 xenografts. Results The synthesis of dual-conjugates comprising an ER-targeting and a nuclear-targeting moieties was successfully achieved by following an orthogonal strategy. The In-/111In- complexes of the hybrid conjugates were successfully prepared and the radiolabelled conjugates demonstrated high stability. The prepared dual-targeting radiolabelled probes [111In]ER3AO, [111In]E2NLS and [111In]E2AO demonstrated high nuclear internalization (higher than 50%) in MCF-7 cells, proving the efficacy of the applied nuclear-targeting approaches. Moreover, [111In]ER3AO demonstrated ability to cause direct damage in DNA. Preliminary biodistribution studies of [111In]ER3AO in tumor-bearing mice were also encouraging since high in vivo stability, fast blood clearance from blood and uptake in the ER-rich organs and in the tumor as well as high target tissue/ non-target tissue radioactivity ratios were obtained. Conclusion A straightforward and versatile synthetic approach was used for the synthesis of bifunctional radioconjugates bearing two different molecular entities. The favourable biological results of the 111In-conjugates in cellular and animal models represent promising properties for the development of radiopharmaceuticals for Auger therapy. Acknowledgments F. Vultos thanks FCT for PhD grant (SFRH/BD/84509/2012). The work was supported by UID/Multi/04349/2013.
22:00 Radiopharmaceutical production of 68Ga-PSMA at the National Cancer Institute. Bogotá-Colombia. - NIDIA ESPERANZA DELGADO LOPEZ (INSTITUTO NACIONAL DE CANCEROLOGIA)
Radiopharmaceutical production of 68Ga-PSMA at the National Cancer Institute. Bogotá-Colombia.
- NIDIA ESPERANZA DELGADO LOPEZ (INSTITUTO NACIONAL DE CANCEROLOGIA)
22:00 - 22:15
Background 68Ga-prostate-specific membrane antigen (PSMA) radioligand diagnostic is a novel diagnostic option in patients with metastatic prostate cancer. The aim of this work was to standardize an efficient automated synthesis method for radiolabeling radiopharmaceutical-grade 68Ga-PSMA for PET/CT diagnosis of prostate cancer. Methods: We employed PSMA-HBED-CC (PSMAHBED) peptide manufactured according to GMP requirements (purity >96%) obtained from ABX (Advanced Biochemical Compounds) and 1850 MBq ITG 68Ge/68Ga generator consisting of organic-matrix column metal free. Sodium acetate, ascorbic acid, NaCl, HCl Ultrapur and EtOH was obtained from Merck Automated synthesis module “Taddeo” from COMECER was installed in a shielded Hot cell and used for radiolabeling. The 68Ga solution was eluted from the generator with 7mL of 0.1M HCl at a flow rate of 2.5mL/min and transferred to a PS-H+ column and eluted with 5M NaCl (1.8mL) . The total 68Ga activity (1400MBq) were transferred directly into the reaction vessel containing 5µg PSMA-HBED-CC peptide, dissolved in 1mL of Acetate buffer 1.0M with pH 4 and Ascorbic acid 10µL, heated to 92oC per 8 min. To process the radiolabeling product Strata-X-tubes pre-conditioned (Phenomenex) were used. The 68Ga-PSMA-HBED-CC was retained and unreacted 68Ga passed through into a waste vial. The Strata-X-tubes were then washed with 5mL of pure water and the 68Ga-PSMA HBED-CC was recovered with 1.2mL EtOH/Water (1:1) followed by 10 mL of 0.9% saline. Finally the product was sterile-filtered under aseptic conditions through 0.22µm membrane filter (Milex-GV, Millipore) and the activity was measured in a Capintec-CRC-15R dose calibrator. The radiochemical purity and identity of the 68Ga-68Ga-PSMA solution was assessed by RP-HPLC equipped with a UV and ɤ detector. A Lichospher-100 column C-18 ( 25mm x 4.6mm, 5µm) , was used as stationary phase. The mobile phase was as follows: 0-0.5min: 95%B; 0.5-10min: a linear gradint 80% A, flow rate 2ml/min (6). Retention times were 1.5- 2.0 min for free 68Ga (III) and 4.9- 5.1 the themodynamically more stable diastereomer (RR), 5.2- 5.4 the thermodynamically less stable. An indicator strip was used for the pH analysis of the 68Ga-PSMA dose and the Bacterial endotoxin content was analyzed using an Endosafe R system (LAL test), the values limit were <175/IU/ml. The sterile filter integrity test of the 68Ga-PSMA solution was performed with a limit value >50psi 68Ge-contamination was detected and quantified using a gamma counter (at full open window and at a 1min measurement time) retaining the preparation for at least 48h to allow 68Ga to decay to a level allowing the detection of the impurities. The total radioactivity due to 68Ge must not be >0.001% referred to the original activity. Radionuclidic identity and purity tests were performed by gamma-ray spectrometry and the principal gamma peaks analyzed, energies of 511Kev and 1077Kev were only allowed. The physical half-life was measured 3 times using a Capintec-CRC-15R Radioisotope Dose Calibrator. The half-life must be 62-74min. Sterility test was performed by an external laboratory, according to the current US-pharmacopoeia. Results: The synthesis of 68Ga -PSMA-HBED-CC parameters were optimized as described previously with 75% +/- 5% decay corrected radiochemical yield . The production of 68Ga- PSMA-HBED-CC was within 28 min+/-1. Over the study period we made 52 synthesis of 68Ga- PSMA-HBED-CC. The radiochemical purity was >99.7% as two diastereomers, with pH range 5.5-7.0. The 68Ge impurities was found to be <0.0010% in the radiolabelled compounds. All samples passed the bacterial endotoxin test at values <10IU/mL and the sterility test. The residual solvent of the final product was ethanol in less than 10%. Up date we have injected 45 patients. Conclusion: We have shown that it is possible to perform an automated sinthesis to 68Ga- PSMA-HBED-CC using an Automated synthesis module “Taddeo” from COMECER ensuring a quality and high radiochemical yields and radiochemical purity > 99.7%. REFERENCES 1. Zhernosekov KP, Filosofov DV, Baum RP, Aschoff P, Bihl H, Razbash A, et al. Processing of generator-produced 68Ga for medical application. J Nucl Med 2007;10:1741–8. 2. Eppard E, Wuttke M, PhilippL, Nicodemus,Rosch F. Ethanol-Based post-processing of Generator-Derived 68Ga Toward Kit-Type preparation of 68Ga-Radiopharmaceuticals. J Nucl Med 2014; 55: 1023-1028. 3. Martin R, Juttler, S Muller M, Wester H, Cationic eluate pretreatment for automated synthesis of [68Ga]CPC4.2 Nucl. Med. Biol. 2014 41, 84-89. 4. Eder M, Schafer M, Bauder-Wust U, et al, 68Ga-Complex lipophilicity and the targeting property of a urea-based PSMA inhibitor for PET imaging. Biocon. Chem 2012, 23, 688-697. 5. Mattias Eder, Neels O, Müller M, et al. Novel preclinical and radiopharmaceutical aspect of [68Ga]Ga-PSMA –HBED-CC: A new PET tracer for imaging of prostate cancer. Pharmaceuticals 2014 7, 779-796 6. Decristoforo C, Knopp R, Von Guggenberg E, Rupprich M Deger T, Hess A, Virgolini I, Haubner R. A fully automated synthesis for the preparation of 68Ga-labelled peptides , Nucl Med Commun 2007; 28 (11) :870-875. 7. Boschi S, Jodi F, Malizia C, Cicoria G, Marengo M. Automatization synthesis modules review. Appl.Radiat.Isotopes. 2012.09.10. 8. Mease R, Foss C, Pomper M, PET Imaging in prostate cancer: focus on prostate-specific membrane Antigen, Curr Top Med Chem 2013, 13 (8) 951-962. 9. Kelly J, Amer-Coarasa A, Nikolopoulou A, Kim D, William C, et al. Assessment of PSMA targeting ligands bearing novel chelates with application to theranostics:stability and complexation kinetics of 68Ga+3, 111In+3, 177Ju+3, 225Ac+3. <nucl. Med. And Biol. 55 (2017) 38-46 10. Barinka C, Byun Y, Dusich CL, Banerjee SR, Chen Y, Castanares M, Kozikowski AP, Mease RC, Pomper MG, Lubkowski J. Interactions between human glutamate carboxypeptidase II and urea based inhibitors: structural characterization. J Med. Chem. 2008; 51:7737–7743 . 11. Eiber M, Maurer T, Souvatzoglou M, et al. Evaluation of hybrid 68Ga-PSMA ligand PET/CT in 248 Patients with biochemical recurrence after radical prostatectomy. J Nucl Med. 2015 ; 56 :668-674.
22:15 Synthesis and biodistribution of 1-((2-methoxyphenyl) piperazine)ferrocenecarboxamide labeled with technetium-99m as a potential brain receptor imaging ag - Nadia Malek (CNSTN)
Synthesis and biodistribution of 1-((2-methoxyphenyl) piperazine)ferrocenecarboxamide labeled with technetium-99m as a potential brain receptor imaging ag
- Nadia Malek (CNSTN)
22:15 - 22:30
he goal of this study is to develop a novel brain receptor imaging agent. This study reports the synthesis, characterization and the biological evaluation of 1-((2-methoxyphenyl) quickly (radiolabelling time < 5 min.), in 90 % yield. The 99mTc-complex, characterized piperazine)ferrocenecarboxamide labeled with technetium-99m (99mTc-MP). The 99mTc-MP was obtained by HPLC (20 to 50% ACN of 0 at 5 min then 50% ACN of 5 at 17 min to finally with 50 at 20% ACN of 17 at 20 min), is stable, neutral and lipophilic enough to cross the blood-brain barrier which was confirmed by octanol/water partition coefficient (LogP = 1.82). In vivo biodistribution indicated that this complex had exceptional brain uptake (2.47% ID/g at 5 min and 0.75% ID/g at 60 min). The distribution of the activity at 15 minutes post-injection in various rat brain regions showed a higher accumulation in the hippocampus area. After blocking with 8-hydroxy-2-(dipropylamino) tetralin, the uptake of hippocampus was decreased significantly from 0.87% ID/g to 0.21% ID/g at 15 min p.i., while the cerebellum had no significant decrease. The new 99mTc-cyclopentadienyltricarbonyl technetium complex reported here showed promising biological results, making it an interesting starting point for the development of a new 99mTc-complex as brain receptor imaging agent.
22:30 Development and Evaluation of 18F-radiolabeled Acetaminophen (Paracetamol) for Tumour Imaging Based on COX-2 Overexpression - SAIKAT NANDY (RMC,BARC,MUMBAI,INDIA)
Development and Evaluation of 18F-radiolabeled Acetaminophen (Paracetamol) for Tumour Imaging Based on COX-2 Overexpression
- SAIKAT NANDY (RMC,BARC,MUMBAI,INDIA)
22:30 - 22:45
Background of the Study: Overexpression of COX-2 receptors is observed in a variety of tumour. Therefore, development of suitable 18F-labeled PET radiotracers of selective COX-2 inhibitors is an attractive option to target selective and specific inhibitors of COX-2. The binding free energy [∆G(-KCal/mole)] of Acetaminophen and F-18 labelled derivative of Acetaminophen have been calculated using AUTODOCK 4.2 and crosschecked using www.swissdock.ch against the PDB code 3LN1 and has been found to be comparable in both cases. This encouraging result provides the necessary impetus towards development of F-18 labelled derivative of Acetaminophen based on its property of selective COX-2 inhibition in designing PET radiopharmaceutical for tumour imaging. Herein, we report the fully automated radiosynthesis of the novel F-18 Fluoroethylated paracetamol by direct radio-fluoroethylation of paracetamol and subsequent purification with SEP-PAK® cartridge purification. The evaluation of the PET radiotracer has been carried out by PET/CT imaging, bio-distribution in mice tumour model and histopathological studies. Methodology: The fully automated radiosynthesis of 18F-Fluoroethylated paracetamol using general purpose synthesis module which, in principle, is similar to GE TRACERlab FXFDG , has been carried out in three steps: (i) Radiosynthesis of the fluoroethylating agent, [18F]Fluoroethyl tosylate (ii) Coupling of [18F]Fluoroethyl tosylate with paracetamol in DMSO solvent and (iii) purification by SPE using Sep Pak® Plus ALOX N cartridges. Pharmacokinetic studies was evaluated by PET/CT imaging study in healthy rabbit at two different time points. Biodistribution study was carried out in nude mice bearing tumour (MDA-MB-231). COX-2 overexpression in tumours was confirmed by histopathological studies. Results: The non-decay corrected radiochemical yield is around (25±3) % (n = 3) within 60±2 mins (total synthesis time). The radiochemical purity is > 95 % as confirmed by radio-TLC and radio-HPLC coupled with UV (λ=276 nm). Biodistribution study demonstrated significant tumor accumulation and retention over a period of two hours post injection. COX-2 overexpression in tumour was confirmed by histopathological studies using mouse anti-COX2 antibody. One-hour post injection PET/CT imaging study in healthy rabbit showed very fast clearance from liver and blood, however, with high accumulation of the tracer in highly proliferating regions like bone marrow and sub-mandibular jaws. The thick leg joints showed significant uptake which can be attributed to age related inflammation in aged rabbit and the well-known fact that COX-2 is overexpressed in inflammation. Both the kidneys as well as urinary bladder showed very high tracer accumulation indicating clearance via renal route. The PET/CT image of two-hours post injection showed complete blood clearance with elimination via renal route, however with bone marrow accumulation. No bone uptake other than the thick joints was observed throughout the period of PET/CT study confirming in vivo stability of the tracer. Thick joint uptake can be attributed to age-related inflammation of the aged rabbit and the well-known fact that COX-2 is overexpressed in inflammation. Conclusion: F-18 labelled Paracetamol has successfully been designed, developed and evaluated as a PET tracer for tumour imaging agent based on COX-2 overexpression in a variety of tumours.
22:45 Study of the physicochemical stability of HMPAO-Technetium (99mTc) - Najla AYACHI (Ministère de la santé)
Study of the physicochemical stability of HMPAO-Technetium (99mTc)
- Najla AYACHI (Ministère de la santé)
22:45 - 23:00
Background and Objective: 99mTc-labeled hexamethylpropylene amine oxime (HMPAO) is used in cerebral perfusion scintigraphy. The manufacturer recommends its utilization within 30 minutes after preparation. Each reconstituted vial allows us to perform 2 scintigraphic scans. However, some circumstances (preparation of patient, duration of acquisition per patient, availability of the γ-camera), make the use of the 99mTc-labeled HMPAO within 30 minutes hard to reach. Our aim is to study the stability of this product beyond the period of use recommended by the manufacturer. Methodology: We used Ceretec® as cold kit and a fresh eluate of 99mTc (Ultratechnekow® generator). The preparation was carried out under the direct control of the radiopharmacist, respecting the manufacturer’s instructions. The control of Radiochemical Purity (RCP) was made by thin layer chromatography (TLC) from the 30th minute of reconstitution. We used a silica plate (Macherey-Nagel®) as stationary phase and two types of solvents (methyl ethyl keton, sodium chloride 0.9%) as mobile phase in order to separate respectively: free-99mTc (〖TcO〗_4^-) and reduced-99mTc associated with a secondary complex99mTc-HMPAO (〖TcO〗_2+CII). The TLC plates were read by γ-camera (Ecam®). Results and Discussion: We carried out quality controls on several HMPAO preparations at times: t0=30 min; t1=60 min; t2=90 min. At t0, the average of the RCP was 86.5% (average of the impurities 〖TcO〗_4^-=4% 〖TcO〗_2+CII=11%). For t1, there was an increase in the percentage of the mixture ( 〖TcO〗_2+CII) from 11% to 16.5%, resulting in a decrease in the average of the RCP (82%). After 90 min, the RCP further decreased to an average of 76% (〖TcO〗_4^-= 4.5%, 〖TcO〗_2+CII= 19.5%). According to the manufacturer's recommendations, the preparation of 99mTc-HMPAO can only be used if the RCP ≥ 80%. Conclusion: The stability study showed that the 99mTc HMPAO is stable beyond 30 min up to 60 min after preparation. Thus, the product is stable for 60 min allowing flexibility of use. Further tests are needed to validate these results.
23:00 Radiosynthesis of 1-{4-[4-(2-[18F] Fluoroethoxy)-phenyl] Piperazine-1-yl} ethenone and its evaluation in animal models bearing C57BL6 melanoma xenograft - SOMNATH KAR (BARC)
Radiosynthesis of 1-{4-[4-(2-[18F] Fluoroethoxy)-phenyl] Piperazine-1-yl} ethenone and its evaluation in animal models bearing C57BL6 melanoma xenograft
- SOMNATH KAR (BARC)
23:00 - 23:15
Radiosynthesis of 1-{4-[4-(2-[18F] Fluoroethoxy)-phenyl] Piperazine-1-yl} ethenone and its evaluation in animal models bearing C57BL6 melanoma xenograft Somnath Kar1, Lakshminarayanan. N1 , Avik Chakraborty1, Yogita Pawar1, Sutapa Rakshit1 and Sharmila Banerjee1,2* 1. Medical Cyclotron Facility, Radiation Medicine Centre, BARC, Parel, Mumbai, INDIA 2. Homi Bhabha National Institute, Trombay, Mumbai, INDIA Somnath Kar (Email: somnath.chem2013@gmail.com Mob: 9733940428) Abstract Background and objective: Sigma receptors were initially described to be a subtype of opioid receptor, but later due to its unique characteristics it has been postulated as a distinguished receptor system. It is divided into Sigma 1 and Sigma 2 subtypes. Sigma receptors are well known for their over-expression in high density, in different types of tumors as in those of breast, melanoma, non-small-cell lung carcinoma, prostate, glioma and tumor of neural origin. Literature study shows that piperidine or piperazine moiety is an important pharmacophore showing binding affinity with the sigma receptors overexpressed on specific tumors. The present effort is directed towards radiosynthesis of [18F]fluoroethylated analogue of 1-Acetyl-4(4-Hydroxyphenyl) piperazine and evaluation of its potential as a tumor marker. Materials and Method: 18F-ﬂuoride production and radiosynthesis were performed using GE PETtrace cyclotron and GE TRACERlab module (Configured for 2-[18F]FDG production) respectively. [18F] radiofluorination was carried out using dry [18F] tetrabutylammonium fluoride. The radiosynthesis was carried out by a one-pot, two-step process. In the first step, [18F]fluoroethyl tosylate was synthesized by fluorination of ethylene ditosylate. In the second step, [18F]fluoroethyl tosylate was tagged with piperazine analogue to form [18F]fluoroethylated-piperazine analogue. The reaction mixture was purified using neutral alumina and Light C18 cartridges. The final product was eluted from the column with 10% ethanol. In-vitro cell uptake study was done by using melanoma cell line (B16F10). Bio-distribution in tumor xenograft model was carried out in C57BL6 mice with melanoma. Towards this B16F10 cell line (5x105 cells per mice) were injected in C57BL/6 mice. After 15 days the size of tumor was found to be 0.75-1 cm3. The size was considered to be sufficient for carrying out the studies. [18F] activity of 200 μCi per mice was injected through tail vein. Mice were sacrificed at 30, 60, and 120, min post injection for biodistribution studies. The same mice which was used for bio-distribution after 120 min pi was used for imaging using PET-CT camera at 60 min pi. Result and Discussion: The reaction conditions were optimized in order to obtain maximum yield of the radiolabeled product. The purity of the product was evaluated using Radio-TLC and radio-HPLC analysis and found to be more than 99%. A bed volume of 4 g neutral alumina and two Light C18 cartridges were found to be sufficient for efficient purification. A non-decay corrected radiochemical yield of 30% (n=4) was obtained with the reaction time of 60 min. In-vitro cell binding study shows good uptake in B16F10 cell line. Biodistribution study shows the compound to have good in-vivo stability and a significant tumor uptake till two hours. Tumor/blood ratio was found to increases with time. Hepatic and renal clearance pattern was observed at 120min pi. Conclusions: [18F]fluoroethylated piperazine analogue was successfully synthesized and purified, with a radiochemical purity of 99%. The radiotracer showed sufficient in-vivo stability. Biodistribution studies shows significant tumor uptake. Further uptake studies with different tumor xenograft models are underway.
23:15 [99mTc(N)(DASD)(PNPn)]+ (DASD=1,4-dioxa-8-azaspiro[4,5]decandithiocarbamate, PNPn=bisphosphinoamine) for myocardial imaging. - Bolzati Cristina (ICMATE-CNR)
[99mTc(N)(DASD)(PNPn)]+ (DASD=1,4-dioxa-8-azaspiro[4,5]decandithiocarbamate, PNPn=bisphosphinoamine) for myocardial imaging.
- Bolzati Cristina (ICMATE-CNR)
23:15 - 23:30
**Aim.** 99mTcN-DBODC5 ([DBODC = bis(N-ethoxyethyl)-dithiocarbamate; 5 = bis(dimethoxypropylphosphinoethyl)-ethoxyethylamine]) is the lead candidate of a series of heteroleptic monocationic compounds proposed, for their favorable biodistribution profile, as myocardial perfusion imaging agent (MPIA)[1]. Phase I clinical studies clearly showed that its clinical properties were comparable to those of the commercially available agents. Therefore, modification of 99mTcN-DBODC(5) direct to increase its pharmacokinetic profile, obtaining an ideal myocardial imaging without interference from the adjacent organ activities, would be desirable. This work describes the synthesis, characterization and the biological evaluation of four new cationic 99mTc-nitrido complexes, of general formula [99mTc(N)(DASD)(PNPn)]+ (DASD=1,4-dioxa-8-azaspiro[4,5]decan dithiocarbamate; PNPn=bisphosphinoamine) (Fig 1), abbreviated to 99mTcN-DASD(n), proposed as improved MPIAs [2]. **Methods.** 99mTcN-complexes were synthetized by a two steps reaction. The chemical nature of the compounds was determined by carrier-added experiments supported by radio/UV-HPLC and LC-MS analyses. Mechanistic studies were performed in-cellulo by using drug sensitive human cancer cell lines and the corresponding drug resistant sublines and in-vivo. Biodistribution studies were performed in rats and compared with the distribution profiles of 99mTcN-DBODC(5) and 99mTc-Sestamibi. The in-vitro and in-vivo metabolisms of the best compounds were evaluated by chromatographic methods. **Results.** 99mTcN-DASD(n) compounds were obtained in high yield. Biological studies revealed that the complexes have a fast high initial and persistent heart uptake with rapid clearance from non-target tissues. Among the tested compounds 99mTcN-DASD(5) and 99mTcN-DASD(7) showed improved heart uptake with respect to the gold standard, with a rapid liver washout and superior heart-to-liver ratio. In-cellulo and in-vivo studies demonstrated that the compounds are membrane potential responsive and are avidly transported by Pgp-MRP1. Metabolism studies evidenced a remarkable in-vivo stability of these agents. **Conclusions**. 99mTcN-DASD(5) and 99mTcN-DASD(7) are promising MPIAs. The rapid pharmacokinetic profiles, might shortened the duration of imaging protocols below 30 min allowing the early acquisition of images with high quality. In oncological field, the advantage of the in-vivo pharmacokinetic profile can also be applied to tumor imaging. **References** 1. Boschi, A.; Uccelli, L.; et.al. J. Nucl. Med. 2003, 44, 806–814. 2. Salvarese, N.; Carta, D.; et. al. J. Med. Chem. 2018, 61, 11114–11126.
23:30 Synthesis and biodistribution study by rats of two new 99mTc-Tricarbonyl complexes as potential brain imaging agents - mouldi Saidi (cnstn)
Synthesis and biodistribution study by rats of two new 99mTc-Tricarbonyl complexes as potential brain imaging agents
- mouldi Saidi (cnstn)
23:30 - 23:45
Synthesis and biodistribution study by rats of two new 99mTc-Tricarbonyl complexes as potential brain imaging agents Mouldi Saidi Laboratory of biotechnology and nuclear technology (LBTN) National center of nuclear sciences and technology Background/goal/objective of the study Many radiolabeled PET tracers, which can speciﬁcally bind to 5HT1A receptors, have been developed for in vivo imaging of 5HT1A receptors in living brain with positron emission tomography[1, 2, 3]. However, due to the high cost of cyclotron-produced radionuclides such as 18F, 11C and lack of availability in most nuclear medicine departments (very short half-life), these tracers have limited use in clinical practice. Up to the present technetium-99m is still the most widely used radionuclide in diagnostic nuclear medicine by virtue of its ready availability, low cost and optimal radiation properties (t 1/2= 6 h, 89% photon yield of 140 keV). The development of 99mTc cyclopentadienyltricarbonylpiperidine derivatives, in which Tc+1 is coordinated to cyclopentadienide (C5H5-) and three carbonyl groups, has been reported [4]. These complexes have shown high uptake in the brain of rats and rabbits [5, 6] as well as high affinity to the 5HT1A receptors in rats 20 min after i.v. administration [6]. In order to better understand the structure / biodistribution relationship of piperidine derivatives and to improve brain retention, two new substituted piperidine derivatives were synthesized, radiolabeled and evaluated by biodistribution studies in the rat brain. As Ref. we used a previously published complex [6].This complex has showed a high affinity to the hippocampus rich in 5HT1A receptors but a rapid wash out from the brain. Methodology Three piperidylferrocencarboxylats were synthesized by reaction of the piperidine alcohol with ferrocenecarbonyl chloride to give the corresponding esters (1, 2 and 3.) Radiochemical synthesis is carried out in a microwave according to the following scheme: Results and discussion We replaced the Wenzel method which suffers from inadequate conditions ( high temperature and long reaction time) by a microwave method. This new method allowed us to achieve a higher yield (90%) for a very short time of 2 min and allowed us to avoid heating at 150 ° C. Biodistribution studies In order to increase the brain uptake of tricarbonyl complexes, substituted piperidinol were used for the synthesis of complex 2a and 3a. Both substituted cyclopentadienyl Piperidine can cross easily the blood brain barrier. However, the in vivo studies in rat showed a lower uptake of complex 3a carrying a butyl group in position 4 as compared to previously published data for the reference compound (complex 4a) [6]. On the other hand, the complex 2a carrying a methyl group in position 4 has shown the highest brain uptake (Fig. 3). With the increase of the carbon chain in position 4 a camouflage of the functional group that interacts with the receptors could explain the decrease of the retention Conclusion. Llabeled complexes in the presence of a sterically hindered ester do not affect the time of brain retention.
23:44 A practical method for the preparation of 18F[TFB] labeled with sodium fluoride, using a ITG IQS Fluidic Labelling Module - Juan C Manrique Arias (Instituto Nacional de Cancerología) Osvaldo García Pérez (Instituto Nacional de Cancerología)
A practical method for the preparation of 18F[TFB] labeled with sodium fluoride, using a ITG IQS Fluidic Labelling Module
- Juan C Manrique Arias (Instituto Nacional de Cancerología)
- Osvaldo García Pérez (Instituto Nacional de Cancerología)
23:44 - 23:59
**A practical method for the preparation of 18F[TFB] labeled with sodium fluoride, using a ITG IQS Fluidic Labelling Module** Juan C Manrique-Arias1,3*, Vanesa Izquierdo-Sánchez1, Paulina Munguía1, Esteban Barrera1, H Valdovinos1, Osvaldo García-Pérez2 1Unidad Ciclotrón Radiofarmacia. Instituto Nacional de Cancerología, CdMx, 14080, México 2Departamento de Medicina Nuclear e Imagenología, CdMx, 14080, México 3Unidad Radiofarmacia Ciclotrón, División de Investigación, Falcultad de Medicina, UNAM, CdMx 4150, México. *Email: juancmanriquea@unam.mx **Background:**18F-Tetrafluoroborate (18F-TFB) is a radiotracer, promising iodide analog for PET imaging of thyroid cancer and sodium/iodide symporter (NIS) reporter activity in viral therapy applications. The aim of this study was to Standardization y characterization of new radiosynthesis method of 18F[TFB], in facilities with little infrastructure. **Methods:** 18F was produced in a cyclotron via the 18O(p,n)18F reaction with 18 MeV protons and then delivered to the hot cell and trapped on a QMA and plus accell CM cartridges, the cartridge was rinsed with 10 mL of water and dried with nitrogen for 3 minutes. After this step the QMA was eluted with 1.2 mL of NaCl 0.9 % ([18F]-NaF 740-1850 MBq) in the reactor where it contains 100uL of NaBF4 dissolved in water (10ug) were mixed. The mixture was left to react at 120°C for 20 min venting the reactor every 5 minutes. The crude 18F-TFB product was purified by SPE using a Sep-Pak Alumina Light and plus cartridge, and washed with 1 mL of water. Then it was diluted with 5 ml of isotonic sterile saline and filtered through a hydrophilic 0.22 μm Millex. Radiochemical purity was determined by TLC using SG strips as stationary phase methanol as mobile phase. TLC-strips were analyzed by autoradiography. Preclinical evaluation in Wistar rats was performed using a Focus 120 microPET (UNAM). **Results:** Labeling and formulation took about 30 min, and radiochemical purity of 18F[TFB] was higher than 98%. The radiochemical yield of 18F-TFB was 31.0% ± 0.7% (n=10) uncorrected in a synthesis time of 20 min (Fig 1). The final product 18F-TFB was analyzed for radiochemical purity by both radio-TLC (MeOH, Rf = 0.23 for fluoride, 1.04 for 18F-TFB) and anion chromatography HPLC with a radioactivity detector (retention times, 3.7 min for 18Ffluoride, 7.8 min for 18F-TFB). **Conclusion** Based on the results of radiochemical purity and quality control, we can determine that the method is possible to adapt in facilities where there is little equipment infrastructure. A solid-phase supported synthesis of 18F-TFB was developed via [18F]-*NaF. With the optimized condition, the radiochemical yield of 18F-TFB was 31.0% ± 0.7% (n=10) uncorrected in a synthesis time of 20 min.
An automated synthesis method for Ga-68 labelled ubiquicidin 29-41 - Jannie Le Roux (Stellenbosch University)
An automated synthesis method for Ga-68 labelled ubiquicidin 29-41
- Jannie Le Roux (Stellenbosch University)
23:44 - 23:59
Introduction Published methods for radiolabelling of ubiquicidin (UBI) 29-41 to date describe manual processes. Manual labelling of 1,4,7-triazacyclononane-1,4,7-triacetic acid ubiquicidin (NOTA-UBI) with Gallium-68 (Ga-68) has several disadvantages, including unnecessary radiation exposure to operators, and difficulty to meet Good Manufacturing Practice (GMP) requirements. The aim of this study was to develop an automated synthesis method for the labelling of Ga-68 NOTA-UBI. Materials and methods Ga-68 activity was eluted from an iThemba Labs Ge-68/Ga-68-generator using 0.6 M HCl. This approach to developing an automated method first duplicated the manual method developed by Ebenhan et al. (2014) using the generator, eluant and consumables available at our PET Centre, followed by adaptations of the radiosynthesis to suit the automated module. Radiolabelling yield and radiochemical purity were determined after each labelling experiment to compare the efficiency of each method and changes to the protocols. Ga-68 NOTA-UBI was labelled using the following three generator eluate preparations: the Ge-68/Ga-68 generator was eluted using fractional elution and 1.5 M 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid (HEPES) was added as buffering agent (method 1); fractional generator elution was done and 1.0 M sodium acetate solution was added as buffering agent (method 2); and a cationic exchange-based pre-purification step was utilized to clean-up the full-scale generator eluate from any possible metal impurities and combined with 1.0 M sodium acetate solution as buffering agent (method 3). The pH of all labelling mixtures was adjusted to range between 3.5 – 4.0. Following radiolabeling, a C18-cartridge based separation of Ga-68 NOTA-UBI was performed to free the labelled product from impurities including colloidal Ga-68. This step was performed on all methods. Regardless the methods applied, Ga-68 NOTA-UBI stability and further tests were performed after each radiosynthesis to justify the product validity for human administration. Results NOTA-UBI was successfully labelled (n = 23) with Ga-68 using automated procedures for fractional elution and cationic pre-purification and sodium acetate as buffer. The best percentage labelling efficiency (78.9 ± 3.6, n = 7) was obtained using the cationic pre-purification method. The average radiochemical purity for the cationic pre-purification method was 99.0 ± 1.7 (n = 7). When method 1 was used, the HEPES content in the final labelled product exceeded the limit prescribed in the European Pharmacopoeia which limited further use of HEPES buffer in these labelling methods. Stability and validation studies performed on the Ga-68 NOTA-UBI indicated that both the fractional elution and cationic purification methods comply with specifications for batch release of radiopharmaceuticals intended for human use. Conclusion An automated synthesis protocol using a Scintomics GRP Module has been successfully developed and tested for robustness and repeatability. Both fractional elution and cationic purification automated methods using sodium acetate as buffer can be utilised for the routine synthesis of Ga-68 NOTA-UBI under GMP conditions, demonstrating high radiochemical yield and purity. An automated cationic pre-purification method using sodium acetate resulted in the best labelling efficiency. HEPES as a buffer was however found not suitable for routine labelling of Ga-68 NOTA-UBI.
Bioconjugates of barium ferrite as a Ra-223 carriers in alpha-radioimmunotherapy - Weronika Gawęda (Institute of Nuclear Chemistry and Technology)
Bioconjugates of barium ferrite as a Ra-223 carriers in alpha-radioimmunotherapy
- Weronika Gawęda (Institute of Nuclear Chemistry and Technology)
23:44 - 23:59
Among all alpha particle emitters, only a few nuclides are in considerable interest for alpha-radioimmunotherapy because of their properties, such as half-live, high cytotoxicity and short path length.One of the most important issues, which affects wider use of alpha-radioimmunotherapy in nuclear medicine, is the availability and price of the radionuclides. At-211 is produced by alpha irradiation at high-energy cyclotrons, which are available only in a few scientific centers in the world. Resources of Ac-225 and Bi-213 radioisotope are quite small. On the contrary to Ac-225, Ra-223 (T1/2=11.4d) is already easily (commercially) available. Ra-223 is easily obtained from the Ac-227/Ra-223 generator. Unfortunately, Ra-223 as va member of Alkaline Earth metals forms very weak complexes. Therefore there is a lack of chelators which can effectively bind Ra-223, retain its daughter radionuclides and be coupled to targeting vectors. We propose to use barium ferrite (BaFe12O19) nanoparticles as multifunctional carriers for Ra-223 radionuclide for alpha-radioimmunotherapy and magnetic hyperthermia. Barium ferrite nanoparticles labelled with Ra-223 were synthesized with a hydrothermal synthesis method in the autoclave. The reaction mixture of FeCl3, BaCl2 and 223RaCl2 was alkalized with NaOH solution. Next, the reaction mixture was stirred in autoclave at 210oC for 6 h. Obtained radioactive, magnetic [Ra-223]BaFe12O19 nanoparticles were washed with distilled water and hydrochloric acid (1 mM HCl). Yield of labelling was about 70% (for 100kBq Ra-223). Stability of the obtained radioactive nanoparticles was tested in various biological solutions: 1 mM PBS, 0.9% NaCl and in human blood serum. It is confirmed that Ra-223 was highly retained inside nanoparticles in every tested solution. Only about 25% of Pb-211 (decay product of Ra-223) was released to the solution. Obtained magnetic BaFe12O19 nanoparticles were characterized by transmission emission microscopy and dynamic light scattering. The diameter of synthesized nanoparticles was about 15-30 nm and the determined saturation magnetization of obtained nanoparticles in room temperature was about 42 emu/g. In order to synthesize a radiobioconjugate having affinity to HER2 receptors, the monoclonal antibody trastuzumab was conjugated to the obtained barium ferrite nanoparticles. Firstly, the surface of barium ferrite nanoparticles was modified with 3-phosphonopropionic acid linker, and then, the monoclonal antibodies were coupled to the barium ferrite nanoparticles using the carbodiimide chemistry. Synthesized bioconjugate was characterized by thermogravimetric analysis, dynamic light scattering and were tested for stability in biological fluids. The obtained [Ra-223]BaFe12O19-CEPA-trastuzumab radiobioconjugate almost quantitatively retains Ra-223 and majority of the daughter products. Radiobioconjugate has high receptor affinity towards HER2 receptors expressing on ovarian cancer cells and exhibits high cytotoxic effect in vitro (SKOV-3 cell line). Acknowledgement This work was supported by National Science Centre of Poland (Grant OPUS 2016/21/B/ST4/02133).
CORRELATION BETWEEN THE YIELD OF PRODUCED [18F]FDG AND THE ACTIVITY RETAINED DURING SYNTHESIS - Katerina Kolevska
CORRELATION BETWEEN THE YIELD OF PRODUCED [18F]FDG AND THE ACTIVITY RETAINED DURING SYNTHESIS
- Katerina Kolevska
23:44 - 23:59
The radiosynthesis of 2-[18F]fluoro-2-deoxy-D-glucose [18F]FDG is a routine automated process at the University Institute for Positron Emission Tomography, Skopje, which is performed using an IBA Synthera V2 synthesis module. [18F]FDG is synthesized by nucleophilic fluorination followed by base-catalyzed hydrolysis. The purification of the final product is accomplished by passing the hydrolyzed reaction mixture through purification cartridges (strong cation exchange column, aluminum oxide column and C-18 bonded silica column). The objective of our study is to define whether there is a correlation between the production yield and the activity retained during synthesis. The analysis includes 63 batches of [18F]FDG, performed on the same module. The IFP cassettes and reagents kits were from the same manufacturer (ABX). In all the syntheses were used Waters Sep-Pak cartridges (QMA, Alumina B, C18) and SPure SCX cartridge. The radiochemical purity was determined by thin layer chromatography using Raytest miniGITA TLC scanner. The radioactivity retained on the cartridges, reaction vessels, v-vials, tube connections and [18O]H2O recovery vials, was measured using Biodex Atomlab 500 Dose Calibrator. The results of the radiochemical purity show that the [18F]FDG content is more than 99% of the total radioactivity, in all of the batches. To interpret the results of the measured retained activity, we made five subgroups of the batches, depending on the yield (decay-corrected): less than 50%, 50-55%, 55-60%, 60-65%, more than 65%. One-way analysis of variance shows that there is no statistically significant correlation between the yield variability and the activity retained on the C18, QMA, SCX cartridges, tubes, reaction vessel, v-vial and recovery vial (p>0.05, for all seven correlations). The regression analysis of the activity retained on the alumina cartridge indicates negative linear regression (Fig.1). ![Regression analysis of the retained activity and the yield][1] A conclusion is made that in our automated [18F]FDG synthesis process, there is statistically significant correlation only between the [18F]FDG yield and the amount of radioactivity retained on the alumina cartridge, which adsorbs the unreacted [18F] fluoride. Keywords: [18F]FDG, retained activity, cartridge, yield [1]: http://i67.tinypic.com/2coq7nb.jpg
Clinical indications and labelling procedures influencing in vitro stability and early myocardial uptake of 99mTc-tetrofosmin - Amel Taïbi (Nuclear medicine department ) Salah Eddine Bouyoucef (Department of Nuclear Medicine CHU Bab El Oued, 16000 Algiers Algeria)
Clinical indications and labelling procedures influencing in vitro stability and early myocardial uptake of 99mTc-tetrofosmin
- Amel Taïbi (Nuclear medicine department )
- Salah Eddine Bouyoucef (Department of Nuclear Medicine CHU Bab El Oued, 16000 Algiers Algeria)
23:44 - 23:59
99mTc -tetrofosmin is a lipophilic cationic agent (diphosphine group) used for imaging myocardial perfusion at stress and at rest. The myocardial uptake of technetium 99mTc -tetrofosmin appears to occur by a passive diffusion process however, the uptake and retention curve models of technetium 99mTc -tetrofosmin by myocardial tissue are not well established. Particularly early images for myocardial perfusion imaging and stability of 99mTc -tetrofosmin are not well defined. 15 preparations of 99mTc -tetrofosmin and 40 patients have been used to study the different parameters part of the process of labeling in order to study the stability of 99mTc -tetrofosmin and its early uptake at 5 minutes by myocardial muscle. Parameters which have been studied were the PH, temperature of storage, time of agitation and the way of intravenous injection. Radiochromatography was performed at different times during 6 hours and early myocardial uptake was estimated by the ration heart/mediastinum uptake. Early results confirm that constant agitation and storage temperature are influencing the in vitro stability of 99mTc -tetrofosmin meanwhile clinical indications and the PH of the injected solution of 99mTc –tetrofosmin are influencing the early uptake of 99mTc –tetrofosmin by the myocardium.
Comparative Evaluation of Tc-99m Octreotide, Synthesized by Different Labeling Methods: For Diagnostic Accuracy Assessment in Neuro-endocrine Tumors - Naseer Naseer Ahmed (Department of Nuclear Medicine, AECH-NORI)
Comparative Evaluation of Tc-99m Octreotide, Synthesized by Different Labeling Methods: For Diagnostic Accuracy Assessment in Neuro-endocrine Tumors
- Naseer Naseer Ahmed (Department of Nuclear Medicine, AECH-NORI)
23:44 - 23:59
Neuro-endocrine tumors (NETs) are ranked among uncommon tumors but owing to their multicentric origin, often pose a clinical challenge for their diagnosis and treatment. Developing countries like Pakistan, PET based tumor’s somatostatin receptor (SSR) imaging is limited, Tc-99m based are the key imaging tool for diagnosis, management and assessment of therapy response. Aim : Two HYNIC-TATE radiopharmaceuticals (RP-1 & RP-2) of different origin, methods of labeling and excipient as RP-1(a single vial) while RP-2 (two vial-(HYNIC Conjugate + co-ligand) were used to compare their in-vitro quality and clinical diagnostic efficacy in histo-pathologically known NETs and others for the imaging of SSR avidity, evaluated for utilization in PRRT therapy. The clinical sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of SSR scintigraphy were calculated and compared. Methods: Freshly eluted sodium pertechnetate was used for radiolabeling. The radiochemical purity was checked as per specifications and injected to 75 patients (43 Male, 32 Female: Age: 87-22) of known primary and secondary neuro-endocrine tumors (known histopathology and prognostic markers i.e. synaptophysin, chromogranin and Ki-67 Index). Their Tc-99m-OCT scans were correlated with histopathology, CT and/or MRI reports. Results: It was found that RP-1 average radio labeling efficiency was 96.4±0.2% as complex, 2.4±0.2% as hydrolyzed and 2.6±0.3% free pertechnitate, while in RP-2 was 98.3 ±0.5% labeled, 1.82±0.4 % hydrolyzed and 0.9±0.1% as free pertechnitate. Out of 75 in 39 patients, imaging were performed with RP-1, 23 were found to be true positive, 7 as True negative (T/P) while 9 as false negative (F/N), with sensitivity, specificity, and PPV, NPV of 71.87%, 100%, 100% and 43.75% , while in 36 scan screened with RP-2, 22 were T/P, 6 as T/N, 8 as F/N, with 75.8%, 100%, 100% and 50% sensitivity, specificity, PPV and NPV. For assessment of lesion site specificity, 14 patients with hepatic lesions were imaged with RP-1, showing 71.4% T/P, 21.4 % T/N, while with RP-2, 81.8% as T/P, 18.18% as T/N. Similarly, in NET of lung, both had 100% T/P result. 1 patient of pheocromocytoma was conducted with RP-2 and was found to be T/P. 1 Patient of papillary urothelial carcinoma found as T/P with both radiopharmaceuticals and 1 patient of small cell NET-Gall Bladder, base line scan and post chemotherapy scan with time interval of 6 months, showed progression in disease. Conclusion: The SSR scintigraphy of NET with RP-2 as compared to RP-1 had better labeling efficiency with more sensitivity but equal specificity, having similar positive and negative predictive values. Both can be used for staging and follow-up assessment of patients. Developing countries where accessibility of PET-CT and Gallium derived diagnosis is not very feasible, gamma camera for scintigraphy, augmented by SPECT-CT much enhance the diagnostic accuracy and assessment of treatment response via these radiopharmaceuticals. Keeping this in view, in future the study can be performed by enhancing the number of patients imaged by SPECT-CT and thus further assessing the diagnostic capabilities of these kits.
Comparison of 68Ga-NOTA-Bisphophonate with 99mTc-MDP in 34 patients with skeletal metastases in various type of cancers - Raviteja Nanabala
Comparison of 68Ga-NOTA-Bisphophonate with 99mTc-MDP in 34 patients with skeletal metastases in various type of cancers
- Raviteja Nanabala
23:44 - 23:59
**Background** There is an increasing preference of PET-CT over SPECT for evaluation of metastasis as the former is able to identify more lesions thanks to the higher resolution. Bisphosphonate ligands conjugated to chelates and labelled with 68Ga are good choice as radiopharamceuticals for PET-CT imaging in patients suffering from metastatic cancer. We present the comparison of 68Ga-NOTA-Bisphosphonate (NOTA-BP) with 99mTc-MDP in 34 patients suffering from different types of cancer. **Methodology** 68Ga-NOTA-BP was prepared by adding 4 ml of 68Ga (555- 925 MBq) in 0.01 M HCl to 50 g of NOTA-BP dissolved in 1 ml of 0.25 M sodium acetate buffer and heating at 95°C for 10 minutes. The product is passed through a 0.22 micron Millipore filter and radiochemical purity was estimated by TLC in 0.1 M trisodium citrate buffer. Thirty four patients suspected to be suffering from metastatic bone cancer were administered with 68Ga-NOTA-BP (185-260 MBq) in saline. Imaging was done one hour post injection in a Siemens Biograph PET-CT machine. A low dose CT from head to toe was acquired prior to PET. PET images were done in 2 min per bed. 99mTc-MDP image was acquired in a GE SPECT-CT camera post 3 hour injection of ~740 MBq of activity. A visual comparison of the PET-CT and SPECT images were done. **Results and discussion** Direct comparison was performed between both the scans which were interpreted by a nuclear medicine physician and a detailed analysis was done qualitatively regarding the number of lesions and quality of the images. The number of lesions detected by 68Ga-NOTA-BP PET-CT was significantly higher when compared to the 99mTc-MDP bone scan. Tracer accumulation was seen both in lytic lesions as well as in sclerotic lesions with latter being higher. The uptake of 99mTc-MDP was less in lytic lesions making them difficult to identify. The 2D planar acquisition gathered less information and decreased the specificity especially in suspicious vertebral and rib lesions, which required SPECT-CT acquisition and further clarification. This process made it more time consuming and tedious, whereas 68Ga-NOTA-BP PET-CT obviated the need for it. The image quality of PET-CT was far more superior compared to the planar bone scan. The low dose diagnostic CT for anatomical correlation and attenuation correction which was performed increased the specificity of the study. Better lesion characterization and overall lesion detection was noted in the 68Ga-NOTA-BP scan. Patients could be imaged within 50 to 60 minutes after injection significantly lower than Tc bone scan proving to be more pleasant to the patient. **Conclusion** PET-CT imaging using 68Ga-NOTA-BP is superior to 99mTc-MDP for evaluation of metastatic bone cancer. PET-CT identified significantly more number of lesions as compared to 99mTc-MDP. Routine clinical use of 68Ga based tracers for bone imaging will help in enhancing the utility of 68Ge/68Ga generator.
Complexes of copper and bismuth cations with acyclic and macrocyclic polyamines bearing picolinic pendant arms - Bayirta Egorova (Lomonosov Moscow state university)
Complexes of copper and bismuth cations with acyclic and macrocyclic polyamines bearing picolinic pendant arms
- Bayirta Egorova (Lomonosov Moscow state university)
23:44 - 23:59
B.V. Egorova1, T.P. Kalmykova1, D.V. Likhosherstova1, A.D. Zubenko2, A.A. Bakhareva2, A.B. Priselkova1, Yu.V. Fedorov2, O.A. Fedorova2, S.N. Kalmykov1 1 Lomonosov Moscow State University, 119991 Leninskie Gory, 1/3, Moscow, Russian Federation 2 A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 119991 Vavilova, 28, GSP-1, Moscow, Russian Federation By this time acyclic and macrocyclic ligands with picolinate moieties became very attractive for binding of Pb2+, Bi3+, REE3+ and Cu2+. As soon as linear and cyclic ligands are already used in radiopharmaceuticals and characterized by different benefits and drawbacks we decided to evaluate both types with the same set of picolinic arms. Here we present our first results on complexation of cations with new ligands possessing picolinate arms L1-L4. All ligands were characterized by NMR-spectroscopy, elemental analysis and potentiometric titration. For complex stability study with Bi3+, Cu2+ and Pb2+ potentiometric titration and competitive extraction technique with radioactive tracer were used. Labeling experiments with radioisotopes of 61,64Cu and 207Bi were performed for leading compounds. Dissociative stability of formed complexes in presence of biologically relevant cations as well as rechelation of radionuclides by serum proteins was studied. Control of labeling efficiency and dissociation of complexes was carried out by thin layer chromatography and protein precipitation accompanied by gamma-spectrometry. Obtained results show lower protonation constants of macrocyclic ligands obviously because of presence of carbamide groups. However complexation constants with Cu2+ and Bi3+ for L4 reach quite high values logK=14.6 and 19.6 respectively. Leading complexes with Cu2+ and Bi3+ possess logK=18.7 and 27.7 for L3. The latter characterized by the largest number of donor atoms and absence of amide groups in contrast to L4 demonstrates the most promising complexation ability. Conditions for effective labeling of L3 by 61,64Cu and 207Bi were determined and synthesized complexes were challenged with excess of Ca2+, Fe3+, Zn2+, stable Cu2+ and serum proteins. It was shown that for >95% radiolabeling yield of L3 and L4 by 207Bi is achieved at c(L)=0.4 mM and 1mM and by 61,64Cu at c(L)=0.2 mM for both ligands. BiL3 and BiL4 in presence of serum proteins have shown slow transchelation up to 40% in 1 hour and to 50-60% in 16 hours. It should be noted that acyclic ligand L3 releases cation much faster and it could be the sequence of well-known tendency of linear ligands to form kinetically unstable complexes. Summarizing all obtained results we can conclude that novel picolinate-containing ligands form complexes almost immediately at room temperature and formed complexes demonstrate stability in vitro. This work was supported by Russian Foundation for Basic Research project №18-33-20152.
Design, synthesis and evaluation of a family of 99mTc estradiol derivatives for breast cancer imaging - Maria Emilia Tejeria (Área Radioquímica, Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay.)
Design, synthesis and evaluation of a family of 99mTc estradiol derivatives for breast cancer imaging
- Maria Emilia Tejeria (Área Radioquímica, Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay.)
23:44 - 23:59
Objective: With the objective to develop a potential radiopharmaceutical for estrogen receptors imaging we present the design of a family of 99mTc complexes derived from estradiol, using different oxidation states of the metal and chelating units and studying their influence on the overall properties of the resulting products. Methodology: Ligands were synthesized starting from ethinylestradiol, derivatizing the triple bond to incorporate different donor atoms to coordinate the 99mTc. The selected labeling strategies were the formation of a Tc (I) tricarbonyl complex (C1) with an N,N,O donor atom set, a Tc (V) nitride symmetric complex (C2) with two units of estradiol and dithiocarbamate as bidentade chelator and a Tc (III) 4 + 1 complex (C3) using a ligand bearing an isonitrile moiety and an NS3 tridentate coligand. Characterization stability studies, lipophilicity, protein binding, in vitro cell binding and in vivo overall biodistribution. Results and Discussion: Synthesis of the ligands was successful in all cases, although the difficulty level is remarkably different. The selected labelling strategies rendered the desired 99mTc complexes with high radiochemical purity. However, HPLC purification was required for C3. All complexes showed high stability in labeling milieu and in human serum for at least 3 hours. Lipophilicity expressed as log P (partition coefficient between octanol and phosphate buffer 0.1M, pH = 7.4) was 1.3 ± 0.1 for C1, 0.8 ± 0.1 for C2 and 0.48 ± 0.06 for C3. C3 exhibited the lowest lipophilicity which agrees with the bibliography that indicates that preparation of Tc(III) 4+1 complexes could be a good strategy to reduce the overall lipophilicity . A moderate protein binding in comparison to ethynilestradiol (98%) was observed in all the three cases with values of 33 ± 11%, 41 ± 9% and 46 ± 6, respectively. Binding to MCF7cells was 2.0 ± 0.2%, 6.8 ± 0.9% and 3,33 ± 0,12% respectively, while tritiated estradiol (Estradiol [6.7-3H (N)]) exhibited a binding of 6.6±1.4%. C2, a symmetric Tc(V)-nitrido complex bearing two units of the pharmacophore has the highest binding. Our findings are in agreement with reports that indicate the positive effect of dimerization or multimerization in receptor binding. Biodistribution in normal rats for C1 and C2 showed low blood activity (0.70 ± 0.26% and 5.13 ± 2.49% at 2 hours, respectively). However, liver uptake was very high for C1 (40.8 ± 2.4%) and moderate for C2, (13.0 ± 1.3%). Excretion occurred mainly through the hepatobiliary system with only a minor fraction excreted in the urine. C2 has the properties in vitro and in vivo properties. In vivo studies for C3 are being performed. Conclusion: Influence of the chelating system in the physicochemical and biological properties of Tc-labelled in biomolecules is clearly demonstrated by our experimental results. Consequently, the design of the suitable chelator is crucial in obtaining the biological stability and pharmacokinetics desired for a radiopharmaceutical. Acknowledgments: ANII (FCE_1_2017_1_136416), CAP, PEDECIBA-Química, Bayer Schering Pharma AG, Hans-Jürgen Pietzsch.
Development and evaluation of a 68Ga-labeled Angiotensin peptide coupled to Rhodamine for diagnostic imaging of heart. - M Okarvi Subhani (King Faisal Specialist Hospital and Research Centre. Riyadh 11211, Saudi Arabia.)
Development and evaluation of a 68Ga-labeled Angiotensin peptide coupled to Rhodamine for diagnostic imaging of heart.
- M Okarvi Subhani (King Faisal Specialist Hospital and Research Centre. Riyadh 11211, Saudi Arabia.)
23:44 - 23:59
Objectives: Rhodamine (Rh) is a lipophilic cation, same as 99mTc-MIBI that specifically accumulates in the myocardium. In an attempt to formulate a PET-based cardiac agent with enhanced targeting efficiency, we linked Rh to angiotensin II (Ang II), an 8 amino acid peptide that has been known to play an important role in cardiovascular function. Here we evaluate the 68Ga-labeled Rh-Ang II conjugate for its potential as a cardiac imaging agent. Methods: Rh-Lys(DOTA)-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-CONH2 was prepared conveniently by solid-phase peptide synthesis according to Fmoc/HBTU chemistry. Rh-NHS ester was coupled to the peptide through the amino group of Lys residue and radiolabeled with 68Ga via DOTA chelator. Metabolic stability of the radiotracer was determined in human plasma and in vivo biodistribution and pharmacokinetics was conducted on Balb/c mice and Sprague Dawley rats. Results: The Rh-Ang II conjugate was radiolabeled efficiently with 68Ga (>75%) as determined by radio-HPLC analysis and showed sufficient metabolic stability in human plasma. In mice, the radiotracer displayed efficient clearance from the blood and excreted from the body mainly through the renal route with some elimination by the hepatobiliary system. The radiotracer uptake in the heart was found to be 1.85±0.59% ID/g as early as 30 min post-injection. The accumulation in other major organs including liver, lungs, stomach, intestines and kidneys was below 8% ID/g. A high uptake by these organs may interfere with the efficient visualization of the heart. In case of rats, the radiotracer showed better pharmacokinetic characteristics, with low uptake of radioactivity in the major body organs/tissues (<4.0% ID/g). The uptake of 68Ga-Rh-Ang II in the heart, 1.91±0.65% ID/g, was higher than the uptake found in the blood and muscle resulting in good heart-to-blood and heart-to-muscle ratios. Additionally the radiotracer exhibited cardiac extraction values comparable to 99mTc-MIBI in rat hearts. Conclusions: These results suggest that the combination of two biomolecules is an attractive approach to enhance targeting efficiency and for rapid and efficient diagnostic imaging of heart. Further studies are in progress to determine the full potential of this cardiac imaging agent.
Development of Automatic System for Production of Small Batches of Radioiodine Capsules - Aleksandar Vukadinovic (Vinca Instutute of Nuclear Sciences)
Development of Automatic System for Production of Small Batches of Radioiodine Capsules
- Aleksandar Vukadinovic (Vinca Instutute of Nuclear Sciences)
23:44 - 23:59
Preparation of small batches of custom ordered 131I capsules in hospitals and institutes is often done manually. Operators could be exposed to the significant level of radiation exposure doses during manual preparation of capsules with high activities of 131I. There are few commercial solutions for automatic capsule filling, but those devices are very expensive. We developed a simple and affordable automatic system for this purpose. The goal of this publication is to present and shortly describe function of our system. The system consists of PC controlled device which is dedicated to precise dosage of 131I solution and filling of capsules with different amount of radioiodine activities. The whole device is located into dedicated chamber, shielded by lead bricks. It is known that the solution volume in microliters closely correlates with the activity in mCi, which is a basic principle of our system. The first step in the whole process is filling of known volume of 131I solution into syringe. The next step is filling-out needed volume (i.e. activity) in the capsule and closing it with appropriate cap. The third step includes measurement of 131I activity in the capsule (dose calibrator) and printing its value on the self-adhesive label. The final step is transport of the capsule to a lead container. The whole process is automated, controlled by PC, which is equipped by appropriate software. The advantage of this system is that it is suitable for custom ordered capsules because every capsule it produces can be of desirable activity and calibration date. The list of capsules with their activities and calibration dates can be easily uploaded to the system as an Excel file. Our system reduces the unnecessary radiation exposure of personnel and also prevents errors caused by subjective or objective reasons, which are often the case during manual capsules filling.
Development, characterisation and in vivo evaluation of two 68Ga-labelled NPY analogues as potential tracers for breast cancer imaging. - María Elena Cardoso Moreno (Area de Radioquímica-Facultad de Química-Universidad de la República Oriental del Uruguay-UdelaR)
Development, characterisation and in vivo evaluation of two 68Ga-labelled NPY analogues as potential tracers for breast cancer imaging.
- María Elena Cardoso Moreno (Area de Radioquímica-Facultad de Química-Universidad de la República Oriental del Uruguay-UdelaR)
23:44 - 23:59
Introduction: Receptor targeting with radiolabelled peptides has gained attention in Nuclear Medicine since these are over-expressed in many proliferative processes. In particular, researchers found that Neuropeptide Y (NPY) type 1 receptor is over- expressed in 90% of breast carcinomas. Objective: The aim of the present study was to develop and characterise two 68Ga-labelled NPY analogues with potential application in breast cancer imaging. Two peptides were used (L1, L2), both having the active sequence (Tyr-Arg-Leu-Arg-BPA-Nle-Pro-Asn-Ile-OH), NOTA as a chelator and a molecule of lysine as a spacer. The amino acid sequences of both peptides are identical but L2 has an acetyl group (–COCH3) in the amino residue of the spacer (L1: H-Lys(NOTA)-Tyr-Arg-Leu-Arg-BPA-Nle-Pro-Asn-Ile-OH) (L2: Ac-Lys(NOTA)-Tyr-Arg-Leu-Arg-BPA-Nle-Pro-Asn-Ile-OH). Methodology: Each peptide (100 µg, 5.85x10-5 mmol) was incubated with [68 Ga]GaCl3 (60-100MBq, 0.2 mL), at pH 4.5 and 95ºC for 10 minutes. Physicochemical characterisation included: radiochemical purity (RCP) assessed by RP-HPLC, lipophilicity (through partition coefficient between octanol and phosphate buffer pH 7.4), plasmatic protein binding (PPB) by size exclusion. Stability in plasma and in labelling milieu was assessed up to 2 hours. Challenge with 100 molar excess of diethylenetriaminepentacetic acid (DTPA) was performed by HPLC. Biological behaviour was evaluated in accordance to University Ethics Committee regulations, in female nude mice bearing MCF7 cancer xenograft induced with 1x106 cells injected subcutaneously into the right hind leg. Tumour was allowed to grow 4 weeks up to an average mass of (0.07+0.02)g. Biodistribution was determined one hour post injection of each tracer. Results: Both complexes were obtained with RCP higher than 95% and were stable in plasma and in reaction milieu. Log P values were (68Ga-L1=- 3.2+0.1) and (68Ga-L2 =-2.6+0.1). Protein binding values were (31.7+0.4)% for 68Ga-L1 and (20.1+0.3)% for 68Ga-L2. Challenge with DTPA, in both cases showed high stability and no trans-chelation of the gallium for up to 2 hours. Both complexes showed low blood and muscle uptake and high renal excretion., 68Ga-L2 higher uptake in liver and kidneys compared to 68Ga-L1 . The target/non target ratio expressed as % of injected dose/gram) was (3.5+0.4)% for 68Ga-L1 and (4.7+0.4)% for 68Ga-L2. Conclusions: Labelling strategy was adequate for obtaining both complexes with high RCP and remarkable in vivo stability. Even though both complexes showed similar behaviour, 68Ga-L2 was less hydrophilic and had lower PPB value compared with 68Ga-L1, probably due to the addition of the acetyl group to the amino group of the spacer. Biodistribution studies showed that renal elimination is the main route of excretion in both cases. Although tumour uptake is moderate favourable T/nT ratio encourages performing further studies in cell lines in order to conclude about the potentiality of both tracers as promising radiopharmaceutical for breast cancer imaging. Acknowledgements: ANII (POS_NAC_2016_1_130455), Pedeciba-Química.
Evaluating Quality Control 18F-FDG: Experience in Sultan Qaboos Unviversity Hospital, Oman - Naima Tag
Evaluating Quality Control 18F-FDG: Experience in Sultan Qaboos Unviversity Hospital, Oman (Production of PET- and SPECT-based diagnostic, therapeutic, and theranostic radiopharmaceuticals)
- Naima Tag
23:44 - 23:59
The Abstract is in the attachment. Please see the attachment of Ms Naima Tag.
Exploring Ga-68 Trastuzumab Fab for noninvasive PET imaging to detect HER2 expressing lesions. - Jaya Shukla (Department of Nuclear Medicine)
Exploring Ga-68 Trastuzumab Fab for noninvasive PET imaging to detect HER2 expressing lesions.
- Jaya Shukla (Department of Nuclear Medicine)
23:44 - 23:59
Background: HER 2 is a transmembrane protein expressed in variety of tissues involved in cell development, proliferation and differentiation. Amplification of HER2 gene leads to overexpression of HER2 receptors and uncontrolled growth. HER2 expression is associated with aggressiveness of tumor. The anti HER2 monoclonal antibody, Trastuzumab (145 kDa), binds to domain IV of HER2 receptor and inhibit the tumor growth. The fragment of trastuzumab bearing antigen binding site, Fab (45 kDa), is explored for imaging HER2 expression in breast cancer patients. Methodology: The Trastuzumab Fab was generated with papain digestion and conjugated with a bifunctional chelating agent NOTA. The NOTA conjugated Ga-68 trastuzumab Fab was separated and was radiolabeled with freshly eluted Ga-68 from Ge-68/Ga-68. Radiolabeled Ga-68 NOTA- Ga-68 trastuzumab Fab (Ga-68 trastuzumab Fab) was separated using PD-10 column and passed through 0.22 μm filter for sterility. The radiochemical purity of Ga-68 Fab was assessed by paper chromatography using sodium-citrate (pH-5.5) as mobile phase, apyrogenicity with PTS and sterility in culture broth for 7 days. The patients (n=7) with immunohistochemistry (IHC) proven HER 2 expressing breast cancer (n=7) and HER 2 negative (n=2) were recruited. The F-18 FDG PET/CT was done in all patients. After obtaining permission from Institute and informed written consent from patients, Ga-68 trastuzumab Fab (3-5 mCi) was injected and PET/CT was acquired after 1.5, 3.0 hr. Scans were analyzed by two nuclear medicine physicians and compared with F-18 FDG findings. Results and discussion: The Fab region of trastuzumab is responsible for binding with HER2 ligand binding domain. Fab was generated by papain digestion and separated by desalting (P-10 column). The NOTA conjugation was standardized at 4°C and 22-24 hours incubation time and average 1.5 NOTA molecules per Fab (MALDI-TOF) were conjugated at 25:1 molar ratio of NOTA:Fab. The Labeling efficiency of Ga-68 trastuzumab Fab was more than 50% and after purification, the radiochemical purity was >95%. The Ga-68 trastuzumab Fab was found sterile and pyrogenic. Ga-68 trastuzumab Fab MIP PET image showed high blood pool activity at 1.5 h, which was decreased at 3 h. However, high kidney and bladder activity demonstrated clearance by renal route. The uptake at primary and metastatic lesions was visualized at 1.5 h and increased at 3 h, in terms of SUVmax, in all HER 2 expressing patients. However, no uptake was observed in HER 2 negative patients. The liver uptake was noted in all patients. The lesions detected on Ga-68 trastuzumab Fab PET/CT were comparable with F-18 FDG PET/CT. To best of our knowledge this is the first human study using Ga-68-Fab. Conclusion The Ga-68 Fab has been formulated and demonstrated potential for targeting HER2 positive lesions. In future, this imaging could be utilized to demonstrate the pattern of HER2 receptor throughout the body before and after trastuzumab and trastuzumab radioimmunotherapy therapy.
Formulation and Radiolabelling of Ethambutol with Technetium-99m for Detection of Extrapulmonary Tuberculosis - Wening Lestari (Center for Radioisotope and Radiopharmaceutical Technology,National Nuclear Energy Agency)
Formulation and Radiolabelling of Ethambutol with Technetium-99m for Detection of Extrapulmonary Tuberculosis
- Wening Lestari (Center for Radioisotope and Radiopharmaceutical Technology,National Nuclear Energy Agency)
23:44 - 23:59
ABSTRACT Background. According to World Health Organisation (WHO) tuberculosis (TB) is one of the top 10 causes of death worldwide. It was also reported in the world in 2017 that 10 million people fell ill with TB and 1.6 million died from the disease. TB is an infection caused by the bacterium Mycobacterium tuberculosis. TB usually attacks lungs, but it can also spread to other organs, this TB is commonly called extrapulmonary TB. This type of TB is relatively difficult to be detected by conventional methods, therefore a proper and specific method is needed. Center for Radioisotope and Radiopharmaceutical Technology (CRRT) – National Nuclear Energy Agency of Indonesia (BATAN) has been developed single-vial ethambutol radiopharmaceutical kits which can be used to detect this type of TB. The single-vial ethambutol kit is an improved form of the previous developed two-vial ethambutol kits. Methodology. Lyophilized ethambutol kits aseptically prepared in the clean room. and consisted of ethambutol, SnCl2.2H2O, mannitol and sodium pyrophosphate. Lyophilization of ethambutol kits was performed using freeze dryer with freezing step, primary drying and secondary drying for 42 hours,3 hours and 3.5 hours respectively. Evaluation of single-vial ethambutol kit included clarity, pH, radiochemical purity, sterility and endotoxin. Radiochemical purity, sterility and endotoxin tests were performed using thin layer chromatography, direct inoculation and Tachypleus Amebocyte Lysate (TAL) respectively. Radiolabelling of ethambutol with technetium-99m was prepared by incubating the kit erials dissolved in 1.5 mL of Tc-99m at room temperature for 10 minutes. Results dan Discussion. Freeze-dried and sterile ethambutol kit has been prepared. Each ethambutol kit vial comprised a lyophilized mixture of 3.5 mg ethambutol, 1 mg SnCl2.2H2O, 5 mg mannitol and 17.5 mg sodium pyrophosphate. Radiolabelling of single-vial ethambutol was carried out using 1.48 GBq of Tc-99m to result in a clear 99m Tc-ethambutol complex with radiochemical purity of above 85% and pH 9. Endotoxin test which performed using TAL gave concentration Lysate < 0.25 EU/mL. The sterile lyophilized single-vial ethambutol kits, radiolabeled with Tc-99m, have been clinically test for diagnosis of extrapulmonary TB in adult as well as children patients at Hasan Sadikin Hospital, Bandung, Indonesia. The result showed that 99mTc-ethambutol can be used as a safe, effective and non-invasive alternative modality for diagnosis of extrapulmonary TB. Conclusion. Freeze-dried ethambutol kit, a sterile product, has been developed and suitable for diagnosis of extrapulmonary tuberculosis. Keywords : tuberculosis, extrapulmonary, ethambutol, technetium-99m,99mTc-ethambutol.
Freeze-dried kit formulation of 177Lu- and 90Y-labeled immunoconjugates of Trastuzumab – formulation and characterization - Emilija Janevik-Ivanovska (Faculty of Medical Sciences, Goce Delcev University Stip, Republic of Macedonia)
Freeze-dried kit formulation of 177Lu- and 90Y-labeled immunoconjugates of Trastuzumab – formulation and characterization
- Emilija Janevik-Ivanovska (Faculty of Medical Sciences, Goce Delcev University Stip, Republic of Macedonia)
23:44 - 23:59
Trastuzumab is a monoclonal antibody for treatment of HER2 positive breast cancer. Immunoconjugate of this antibody labeled with lutetium-177 and yttrium-90 has been investigated as potential radiopharmaceutical for radioimmunotherapy. In our study, the labeling was done via DOTA, DTPA and 1B4M-DTPA as a chelator in a molar ratio of 1:20. Material and Methods: Several techniques have been used to characterize the stability and retained immunoreactivity of the antibody in the formulated immunoconjugates. A protein integrity and purity were accessed by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE). Vibrational (infrared and Raman) spectroscopy provided molecular structure information and was found convenient for verification of possible changes in the secondary structure. The number of chelating groups per one trastuzumab molecule was obtained by MALDI-TOF-MS. After conjugation, the freeze-drying process was performed to obtain stable immunoconjugates for further labeling. Quality control and stability were examined by ITLC using a three different mobile phases (0.9% saline solution, 0.4 M methanol:sodium acetate (1:1) and 0.1M acetic buffer). Results: The same intensity of the fragments (25 kDa for light chain and 50 kDa for heavy chain) of lyophilized immunoconjugates and pure trastuzumab indicated that there is no degradation of the antibody. The presence of characteristic amide bands in infrared spectra (amide I (1700-1600 cm-1), amide II (1480-1575 cm-1) and amide III bands (1255-1244 cm-1) and Raman spectra (amide I band at ~1670 cm-1 and amide III band at 1230-1300 cm-1) have also indicated that all samples have retained native secondary structure. An average of 3.92 p-SCN-Bn-DTPA, 3.69 p-SCN-Bn-DOTA and 4.43 1B4M-DTPA groups could be randomly conjugated to an antibody molecule, which represent promising result for successful labeling. After labeling with 177Lu and 90Y (specific activity of 200 µCi/mL), radiochemical purity and stability studies were performed using ITLC method in 0.9% NaCl and 0.4 M methanol:sodium acetate (1:1) as an appropriate mobile phase. The stability studies after 72 h have revealed that 177Lu-labeled trastuzumab is more stable (< 10% of the released 177Lu) than 90Y-labeled one (< 25% of released 90Y). Conclusion: Our study shows successful formulation of stable radioimmunoconjugates which makes this proposed freeze-dried kit as potential radiopharmaceutical in vivo investigations. Key words: Trastuzumab, Bifunctional Chelators, Radiolabeling, Lutetium-177, Yttrium-90.
Fully Automated Radiosynthesis of 18F-16-α-Fluoroestradiol ([18F]FES) With Solid Phase Extraction Cartridge Purification by Sep Pak® Plus ALOX N - SAIKAT NANDY (RMC, BARC, MUMBAI, INDIA)
Fully Automated Radiosynthesis of 18F-16-α-Fluoroestradiol ([18F]FES) With Solid Phase Extraction Cartridge Purification by Sep Pak® Plus ALOX N
- SAIKAT NANDY (RMC, BARC, MUMBAI, INDIA)
23:44 - 23:59
Background of the Study: The utility of [18F]Fluoroestradiol ([18F]FES), a fluorinated steroidal tracer for determining the tissue estrogen receptor level of breast cancer patients is clinically proven. This radiotracer is thus used in prior prediction of the response of antiestrogen therapy of primary, recurrent or metastatic breast cancer. A fully-automated, high-yield synthesis procedure is the key requirement for its availability in large scale, ensuring its wide-spread clinical use. The radiosynthesis of [18F]FES is carried out starting from MMSE (3-methoxymethyl-16α, 17β-epiestriol-O-cyclic sulfone) precursor. The low yield of [18F]FES obtained from this precursor is attributed to difficulties in the hydrolysis and purification steps after the first step radiofluoriation. Herein, we report an improved fully automated and optimized radiosynthesis procedure of 18F-16-α-Fluoroestradiol ([18F]FES) from MMSE precursor, involving hydrolysis with 2N HCl and subsequent purification using SepPak® Plus ALOX-N cartridge. The method is reliable, with considerably improved yield of the product with acceptable radiochemical purity. Methodology: 18F– produced in the medical cyclotron [18O (p, n) 18F] was trapped in perfectly conditioned and dried QMA cartridge and TBA18F was eluted by 0.6 ml 75mM TBAHCO3. 1.2 ml dry acetonitrile was added followed by azeotropic distillation for obtaining extra dry TBA18F. MMSE precursor (2mg/0.8 ml dry MeCN) was added and radio-fluorination was carried out at 120˚C for 15 minutes. Hydrolysis of the radiofluorinated MMSE precursor was carried out at 115˚C for 12 min using 0.7 ml of HCl (2N). The reaction mixture was cooled and around 2 ml of pharmacopeia grade ethanol was added into the reaction vessel, under stirring condition. The reaction mixture was then passed through a stand of four perfectly conditioned SepPak® Plus ALOX-N cartridges discarding the eluent and subsequently dried by-passing helium. Finally, [18F]FES was eluted with 12 ml of 15% ethanol containing water in the product vial. 1.5 ml of 10% NaCl and 0.5 ml of 1(M) NaH2PO4 were added at the beginning of the synthesis in order to maintain acceptable pH and isotonicity of the product. [18F]FES was then dispensed through 0.2µ filter into sterile and bacterial endotoxin free vials. Including its physical properties, radiochemical purity was ascertained by radio-TLC. The product formation is confirmed by comparison of its TLC with that of the authenticated reference standard [19F]FES. Results: The non-decay corrected radiochemical yield was found to be ~ (35±5) % (n = 3) within 60±2 mins. The radiochemical purity (> 95 %) was confirmed by radio-TLC using freshly prepared 95/5 MeOH/NH3 solvent. While [18F]FES has Rf of 0.7, free [18F]F- exhibits Rf of 0.01 and that of the radiofluorinated MMSE precursor is around 0.15. The radiochemical purity of [18F]FES was confirmed by comparing with the authenticated reference standard [19F]FES. [18F]FES obtained was clear, colourless and free of any suspended particle, with pH ~ 6. Conclusion: [18F]FES has been successfully synthesized and purified in good yield using the fluorination module in the medical cyclotron under optimized condition which is identical in principle with GE TRACERLABFX-FDG.
Impact of hospital production vs commercial kits purchase of 68Ga-DOTA peptides. - Julien Costes (Pharmacie, Centre Hospitalier Universitaire Vaudois)
Impact of hospital production vs commercial kits purchase of 68Ga-DOTA peptides.
- Julien Costes (Pharmacie, Centre Hospitalier Universitaire Vaudois)
23:44 - 23:59
Introduction. 68Ga-DOTA peptides, somatostatin analogs, are used for neuroendocrine tumors diagnosis. Commercial kits of 68Ga-DOTATATE are available for this indication with an expansive supplying. The aim of this study is to evaluate the impact of a switch from commercial kits to an hospital production of 68Ga-DOTATOC. Methodology. To synthetize this radiopharmaceutical in our laboratory, a quality dossier has to be submitted to our local authority, Swissmedic. In this dossier, we have to describe the synthesis and quality control (QC) methods and validate them on three batches. Synthesis was done with Mini AiO® synthesis module (TRASIS, Belgium). For each batch, all QC required by European Pharmacopeia (8th edition) were performed. Moreover, an additional filter integrity test was done with Mini AiO® to assess the sterility of the synthesis process. Then, the synthesis of 68Ga-DOTATOC was compared to 68Ga-DOTATATE kits in regards to costs and time of production. Results and discussion. On validation batches, activity yields was 84.4% ± 6.31%. All QC parameters were in conformity with the limits prescribed by Pharmacopeia monography. Calculated radiochemical purity was 99.36% ± 0.15% and residual ethanol measured was 7.77% ± 0.83%. Microbiological analyses (sterility and endotoxin) showed that the entire synthesis process allows sterility conditions. Futhermore, filter integrity test was successful for all batches. Synthesis module is located in a hotcell with a microbiological class A with a regular microbiological monitoring. Sedimentation plate and filter integrity test are also performed before pharmaceutical release. Based on these parameters, sterility and endotoxin analyses will be performed only on validation batches and every 6 months. On one hand, synthesis and QC control of 68Ga-DOTATOC are longer than 68Ga-DOTATATE kits respectively 60 minutes vs 30 minutes and 130 minutes vs 15 minutes. Indeed, more QC are needed for 68Ga-DOTATOC (HPLC, GC) whereas only PRC determination by TLC and pH measurement are required for 68Ga-DOTATATE kits. Thus, additional human resources and materials are necessary for hospital production. But, on the other hand products for 68Ga-DOTATOC synthesis are cheaper than 68Ga-DOTATATE kits. Based on a number of 130 synthesis per year scheduled by nuclear medicine department, hospital production allows to obtain human resources and an important saving for the institution. Conclusion. 68Ga-DOTATOC is conveniently prepared in sterile conditions by using Mini AiO® synthesis module with high radiochemical purity (> 99.3%) and enough final activity for 2-3 patients in a single batch. The advantageous costs saving compared to the commercial kits available in Switzerland prompt to extend this work to other 68Ga radiotracers. Moreover, radioprotection benefits of automatized synthesis vs manual preparation of commercial kits could be assessed in a future study.
Improvement of synthesizing material and method for an in-house production of [18F]-florbetapir PET tracer for imaging beta amyloid deposition in the brain - TOSSAPORN SIRIPRAPA (Faculty of Medicine Siriraj Hospital)
Improvement of synthesizing material and method for an in-house production of [18F]-florbetapir PET tracer for imaging beta amyloid deposition in the brain
- TOSSAPORN SIRIPRAPA (Faculty of Medicine Siriraj Hospital)
23:44 - 23:59
• Background/Goal/Objective of the study; Recently, the (E)-2-(2-(2-(2- [18F]-fluoroethoxy)ethoxy)ethoxy)-5-(4-methylaminostyryl) pyridine) (a.k.a. [18F]-florbetapir) was developed in our laboratory as a radiotracer to detect β amyloid deposition in the brain using PET scan assisting for diagnosis of Alzheimer’s disease. In this research, we aimed to compare the production yield of [18F]-florbetapir obtained from the newly adapted synthesizing materials with optimized method and that of the original method. • Methodology; [18F]-florbetapir was produced at Siriraj Cyclotron Centre using HM-20S cyclotron with CFN-MPS200 module (Sumitomo, Tokyo, Japan). The activated fluoride (18F) was combined to AV-105 precursor by substituting the tosylate leaving group in a fluorination step. Then, 1N hydrochloric acid was added and pH-adjusted with 1N sodium hydroxide to remove the boxylic protecting group with de-protection process or hydrolysis. During synthesizing steps, in the original method (Method A) we used FLT cassette (Sumitomo, Tokyo, Japan) with installed silicone tubes. In the new method (Method B), we replaced all original tubes in FLT cassette with PharMed® BPT tube (Saint-Gobain, Akron Ohio, United States), which was further sent for sterilization at local central sterile supply department (CSSD) before use. Following purification via HPLC semi-preparative, the products from both methods were neutralized with 0.5% sodium ascorbate/water (non-diluted in method A and diluted 1:8 in method B), purified with Sep-Pak tC18 reverse phase column, eluted into the vial containing normal saline and filtrated with 0.22 µm Millex GV filter. The quality control of [18F]-florbetapir was done by standard methods for the determination of basic characteristics of radiopharmaceuticals including appearance, acid-base range, radio chemical purity, residual solvent, pyrogenicity, half-life, chemical impurities, sterility, nuclidic purity and assay of ascorbic acid. The remaining radioactivity inside the tubes, overall yield, specific activity, radiochemical purity and other physical properties from both methods were compared. • Results and Discussion; The remaining radioactivity inside the tubes of method B was 3.23±1.4 (n =4), which was 32.57% decreased from 9.93±1.52% remaining radioactivity in the tubes of method A (n = 3). The recovery rate from tC18 after neutralization with 0.5% sodium ascorbate/water (Method B) was 94.72±6.00%, which was higher than 76.71±4.58% from method A. The overall yield, specific activity and radiochemical purity of [18F]-florbetapir produced by method B were 21.4±0.2% (not decay corrected), 5.24±2.25 TBq/mmol and 96.1±3.2%, respectively, which were higher than 5.7±1.50%, 1.26±0.28 TBq/mmol and 95.84±0.80% obtained from method A. Other physical properties including appearance, acid-base range, half-life, residual solvents (acetonitrile and DMSO), total chemical impurities, assays of ethanol and assays of sodium ascorbate, and bacterial endotoxins of [18F]florbetapir produced by both methods were within standard criteria. • Conclusion; We successfully improved [18F]florbetapir production by optimizing new type of tubing cassette material to use with the automated synthesizer and minor adjustment of neutralization method. This new method provides higher production yield and higher radiochemical purity as compared to our previous method. In addition, this applied cassette is able to reduce production cost, easy to operate and suitable for Siriraj Cyclotron facility.
In house preparation and biodistribution of 64Cu-ATSM, 64Cu-PTSM and 64Cu-DOTATATE for theranostic application - Thaer ASSAAD (AECS)
In house preparation and biodistribution of 64Cu-ATSM, 64Cu-PTSM and 64Cu-DOTATATE for theranostic application
- Thaer ASSAAD (AECS)
23:44 - 23:59
Abstract In this work the radiolabeling and biodistribution of 64Cu-ATSM, 64Cu-PTSM and 64Cu-DOTATATE were carried out. A routine production method of no-carrier-added 64CuCl2 was performed through the nuclear reaction 68Zn(p,αn) 64Cu from high current solid target. By using suitable proton energy, the amount of 67Cu has been neglected end of synthesis which constitute about 1%. High quality ATSM, PTSM and DOTA-TATE were synthesized in our laboratory then characterized by NMR, FTIR spectroscopies and MS spectrometer. All compounds were successfully labeled with 64Cu and the Radiolabelling yields of the labeled compounds were greater than 98%. Biodistribution of 64Cu-DOTATATE were performed at 0.5, 1 and 1.5 hours. Whereas the biodistribution of 64Cu-ATSM and 64Cu-PTSM were carried out at 1, 2 and 3 hours.The results show that 64Cu-DOTATATE, 64Cu-ATSM and 64Cu-PTSM are rapidly and efficiently cleared from the blood. Only less than 1% of the injected activity/g remains in blood pool. Normal 64Cu-DOTATATE biodistribution in kidneys increase and stabilize at 10% of the injected dose per gram at one-hour post injection. Whereas stabilize at 2.5 % of injected dose per gram in the liver healthy cells. 64Cu-ATSM shows a lower uptake in the myocardium than 64Cu-PTSM. Keywords:64Cu-ATSM, 64Cu-PTSM and 64Cu-DOTATATE, biodistribution, Radiolabelling,
In vitro NK1R affinity evaluation of novel radioconjugates based on peptide antagonist SPANTIDE I and Ga-68/Lu-177 theranostic-like isotopes for glioma cancer - Paweł Halik (Institute of Nuclear Chemistry and Technology)
In vitro NK1R affinity evaluation of novel radioconjugates based on peptide antagonist SPANTIDE I and Ga-68/Lu-177 theranostic-like isotopes for glioma cancer
- Paweł Halik (Institute of Nuclear Chemistry and Technology)
23:44 - 23:59
1. Background and goal of the study: The NK-1 receptor and its endogenous agonist - Substance P (SP) is a system that have been connected with many physiological processes like angiogenesis, wound healing and activation of inflammation state mediators synthesis. Moreover, the overexpression of NK-1 receptor is observed on certain types of cancer cells especially glioma, astrocytoma, melanoma, neuroblastoma and some types of lymphomas. This makes NK-1 receptor a potential target for cancer diagnosis and antitumor agents therapy. Presently there are some known glioblastoma treatment trials with labeled derivatives of SP but none of them is effective enough. High affinity to NK-1 receptor exert also antagonists of this receptor. SPANTIDE I [D-Arg1,D-Trp7,9, Leu11]SP is a SP-analogue peptide antagonist designed with higher in vivo stability than natural SP (half-life of 2-3 minutes in human blood). There are also reports that inhibition action on NK-1 receptor can be correlated with antitumor activity of the inhibitor. That is why our goal is to synthetize novel radioconjugates based on peptide antagonist SPANTIDE I and evaluate their affinity and toxicity against glioma cancer cell lines. 2. Methodology: In the course of this research we have synthesize two types of conjugates consisting of DOTA chelator and full peptide SPANTIDE I (1-11) or shorten peptide SPANTIDE I (5-11). Afterwards we have obtained desired radioconjugates by labeling with Ga-68 or Lu-177, and performed an assessment of physicochemical parameters like lipophilicity and stability in human serum. Later, prepared radioconjugates have been evaluated on in vitro assay with chosen NK-1 overexpressed cell lines to determine their affinity to the receptor after structural modification. In the next step cytotoxicity assay has been performed. 3. Results and discussion: We have successfully obtained with high specific activity all four radioconjugates: shorten SPANTIDE I (5-11)-DOTA and full SPANTIDE I (1-11)-(DOTA)2 labeled with Ga-68 or Lu-177. Presence of two DOTA chelators in full SPANTIDE I radioconjugates affects significantly on lower radioconjugates logP parameter in comparison with shorten SPANTIDE I (5-11) radioconjugates with one chelator. All four radioconjugates show full stability in human serum for more than 4 times of applied isotope half-life. In vitro assays confirm maintenance of receptor affinity of obtained radioconjugates on glioma cell line. 4. Conclusion: In conclusion, obtained radioconjugates fulfill many crucial aspects for the potential radiopharmaceuticals strictly required from the clinical application point of view. Gallium-labeled radioconjugates may show an usefulness in diagnosis of NK-1 receptor overexpression and lutetium-labeled SPANTIDE I peptides may complement the therapeutic application by similar in vivo action in theranostic idea of designed radioconjugates. Application concept of peptide NK-1 receptor antagonists may be a helpful reference in further development of tumor treatment solutions.
Influence of 99mTc-chelation at N-terminal and/or C-terminal on receptor binding affinity of NGR peptides - V Kusum Vats (Bhabha Atomic Research Centre)
Influence of 99mTc-chelation at N-terminal and/or C-terminal on receptor binding affinity of NGR peptides
- V Kusum Vats (Bhabha Atomic Research Centre)
23:44 - 23:59
Objective: The NGR peptide has high affinity towards aminopeptidase receptors (APN or CD13 receptors) upregulated in tumor angiogenic blood vessels as well as in melanoma, ovarian, prostate, lung, and breast tumors. This study aimed at determining the influence of modification of NGR peptide at either N- or C-terminal on the receptor binding affinity. Tridentate ligand scaffolds were introduced at N- or C-terminal of NGR peptide via click chemistry for radiolabeling with 99mTc(CO)3-precursor. In vitro and in vivo evaluation of N- and C-terminal radiometalated peptides was performed to determine the effect on receptor binding affinity. Methodology: The N- and C-terminal azide-functionalized NGR peptides, K(N3)c(CNGRC)G-CONH2 (1a) and c(CNGRC)K(N3)G-CONH2 (2a) were synthesized manually by standard Fmoc solid phase peptide synthesis protocol. For N-terminal modification CNGRCG sequence was first assembled on the solid phase followed by coupling of Fmoc-Lys(N3)-OH at the N-terminus. The C-terminal modification of NGR peptide was performed by loading Fmoc-Gly-OH as the first amino acid on the solid phase followed by Fmoc-Lys(N3)-OH. Further CNGRC sequence was assembled and disulphide bridge was formed by cyclization of cysteine sulphides. Subsequent to cleavage from the solid phase and purification by semi-preparative HPLC, the azide peptides were subjected to click reaction with propargyl glycine in solution phase to synthesize peptide constructs K(Pra-Tz)c(CNGRC)G-CONH2 (1b) and c(CNGRC)K(Tz-Pra)G-CONH2 (2b) respectively, containing a tridentate chelating unit for radiolabeling with [99mTc(CO)3]+ core. Peptide constructs were characterized by mass spectroscopy. The radiotracers, 99mTc(CO)3-K(Pra-Tz)c(CNGRC)G-CONH2 (1c) & 99mTc(CO)3-c(CNGRC)K(Tz-Pra)G-CONH2 (2c) were analyzed by HPLC and evaluated for in vitro receptor affinity in murine melanoma B16F10 cells and in vivo pharmacokinetic behavior was determined in C57BL/6 mice bearing melanoma tumor. Results and discussion: The N- and C-terminal azide-NGR peptides (1a and 2a) synthesized manually by solid phase peptide synthesis were obtained in an overall yield of 27% and 31% respectively; with >98% purity. Radiometalation of peptide constructs 1b and 2b resulted in formation of neutral 99mTc(CO)3-NGR complexes, 1c and 2c respectively with >95% radiochemical purity. The C-terminal modified peptide exhibited higher binding affinity towards B16F10 cells in comparison to N-terminal modified peptide (IC50 values 1b: 136  2.3 nM; 2b: 65  1.7 nM). The C-terminal construct 2c exhibited higher uptake in murine melanoma B16F10 cells during in vitro studies. In vivo tumor uptake of 2c was higher than of N-terminal modified peptide construct 1c at 2 h p.i. (2.4  0.5 vs 1.9  0.3% ID/g respectively). Blocking studies carried out by co-injection of cNGR peptide led to ~50% reduction in the tumor uptake at 2 h p.i. suggesting receptor-mediated uptake of radiotracers. Both the radiotracers exhibited rapid urinary excretion and cleared from all the major organs (heart, lungs, spleen, stomach and blood) at 4 h p.i. (<1% ID/g). Conclusion: The N- and C-terminal modified peptide constructs could be radiometalated with 99mTc(CO)3 core in good radiochemical yield (>95%). However higher in vitro cell uptake and in vivo tumor uptake was observed for the C-terminal construct illustrating the preferred conjugation of drugs, dyes, radiometals etc. at C-terminus of NGR peptide.
Influence of the source of Lu-177 on radiopharmacy waste management – an estimate - Sietske Rubow (Stellenbosch University)
Influence of the source of Lu-177 on radiopharmacy waste management – an estimate
- Sietske Rubow (Stellenbosch University)
23:44 - 23:59
Introduction: When radiopharmaceuticals are procured, it is tempting to select based on the cost of the product. In the case of Lutetium-177 for radiopharmaceutical therapy, this may have considerable practical consequences. The radionuclide can be produced using a direct (NCA Lu-177) or an indirect method (CA Lu-177), yielding products with different specific activities and different levels of contamination with Lu-177m, which has a half-life of 160 days. We asked ourselves what the implications for waste management would be if we switched from NCA to CA Lu-177. Methods: Data from 73 Lu-177 therapy doses prepared and dispensed in our hospital were reviewed. Doses were individually prepared, starting with approximately 7.4 GBq Lu-177. The activity of waste from the radiosynthesis procedure (production waste, P) and from dispensing and administration of the patient dose (dispensing waste, D) were calculated. These values were used to estimate potential levels of Lu-177m in waste. Results: Waste P contained an average of 885 ± 336 MBq and waste D 183 ± 106 MBq Lu-177. Assuming that 0.05 kBq Lu-177m is present per 1 MBq CA Lu-177 (Bakker et al, 2006), the waste contents of the longer-living isotope would be 44 kBq and 9 kBq respectively (Table 1). Discussion: In South Africa, radioactive substances with activities less than 100 Bq/g and total activity less than 4 kBq can be disposed as normal waste. On the day of synthesis and administration, all our production waste would have exceeded the 4 kBq limit, while only 10 lots of dispensing waste would fall below that level. In our worst case scenario, even if a facility were to receive a ready-to-use Lu-177 radiopharmaceutical containing Lu-177m, waste from dispensing may have to be stored almost 2 years before disposal. In this study we only considered waste and we excluded patient excreta. For radiosynthesis and therapy, other aspects of the radionuclide, like the effect of low specific activity, should also be carefully considered. Conclusion: The decision regarding Lu-177 procurement should not be based on cost only. If long-living contaminants are likely in a radiopharmaceutical product, waste management and storage facilities will be an important consideration.
LABELLING OF ANTI-CD20 MONOCLONAL ANTIBODY CIMABior WITH 90Y. - Madian Pino Peraza (Centro de Isótopos (CENTIS))
LABELLING OF ANTI-CD20 MONOCLONAL ANTIBODY CIMABior WITH 90Y.
- Madian Pino Peraza (Centro de Isótopos (CENTIS))
23:44 - 23:59
Radioimmunotherapy of non-Hodgkin lymphomas with anti-CD20 monoclonal antibodies (Mabs) labelled with b-emitter radionuclides has resulted promising. The aim of this work was to establish a method for the labelling Cuban chimeric anti-CD20 MAb CIMABior with 90Y. Materials and methods: The influence of 3 BCA (NHS-DOTA, p-SCN-CHX-A”-DTPA and p-SCN-Bn-DOTA) was studied. Conjugation reaction was performed in bicarbonate buffer 0.1mol/L pH=8.5-9.0 at room temperature, varying molar ratio Mab:BCA and incubation times. After conjugation, the antibody was purified by gel filtration and by ultrafiltration through Amicon 30 kDa, and changing to ammonium acetate buffer 0.1mol/L pH=6.0-6.5. Labelling reactions were performed at room temperature and 42 ºC, when DTPA and DOTA derivatives were employed, respectively. A challenging assay against 300-fold molar excess of EDTA was used to assess the stability of radioconjugates. Immunoreactivity was assayed by flow cytometry. To assess the in vivo behaviour of 90Y- CIMABior, 9 male healthy rats received 50 µg of the Mab (37 MBq, 0.2 mL) through marginal vein of the tail. Blood samples were drawn and organ collected up to 72 h. Results: Depending on the BCA and the molar ratio Mab:BCA, the amount of chelating groups bound to the antibody varied in the range from 2 to 13. The same way, the labelling yield also depended on the employed BCA and the number of the chelating groups in the IgG molecule. The conjugates with p-SCN-CHX-A”-DTPA and p-SCN-Bn-DOTA showed the best results of labelling efficiency (>95%). Radioimmunoconjugate CIMABior-Bn-DOTA-90Y showed the highest stability (>90% after 96 h). The affinity of Mab CIMABior for the antigen CD20 was affected by the increasing of the molar excess of BCA in the conjugation reaction. Besides, the affinity for the antigen was significantly lower in case of NHS-DOTA, with regard to the other two immunoconjugates. Immunoreactive fraction of CIMABior-Bn-DOTA-90Y was (95.27 ± 6.21) %. Labelled Mab showed a satisfactory in vivo stability. The main target organ was the spleen (1.2-2.0 %ID/g). Product had an elimination pathway through kidneys and liver. PK study showed a monoexponential with a T1/2 = 7.0 ± 3.1 h. Conclusions: According with the outcomes of the present work, a methodology for the satisfactory labelling of anti-CD20 monoclonal antibody was established. Radioimmunoconjugate CIMABior-Bn-DOTA-90Y showed the most adequate initial characteristics to be used in the future for the radioimmunotherapy of NHL.
Labeling of PSMA-11 with 68Ga in NaHCO3 - Kamila Urbanová
Labeling of PSMA-11 with 68Ga in NaHCO3
- Kamila Urbanová
23:44 - 23:59
**Background** Prostate specific membrane antigen (PSMA) is a type II membrane protein which is widely expressed on the surface of prostate cancer cells. One of the functions of PSMA is to be receptor mediating the ligand internalization. This feature of PSMA is employed in the diagnostic and therapeutic procedures that use PSMA as an antigen target. Over the years, small molecules with high affinity for PSMA have been developed and labeled with positron emitters (e.g. 68Ga, 18F, 11C, 64Cu, or 86Y). One of these radiolabeled ligands, [68Ga] PSMA-11, is the most frequently used tracer for PET imaging of the prostate cancer. PSMA-11 has a strong binding affinity for the PSMA protein and is effectively internalized in the prostate cancer cells. The aim of this work is to test a new approach to the labeling of the PSMA-11 ligand with 68Ga eluted from the Galli Eo generator (IRE Elit) in slightly alkali milieu. **Methodology** The 68Ga-eluate was loaded to the Oasis MCX cartridge. The cartridge was activated before use and thoroughly washed with water after the loading 68Ga. The radionuclide 68Ga was eluted from the cartridge with 0.1M NaHCO3 (pH = 8.5). The precursor PSMA-11 was mixed directly with the eluate. Activities were determined using an ionizing chamber, pH was measured for all samples that were further analyzed by LC-MS and HPLC systems. **Results and discussion** A total of 18 experiments of labeling PSMA-11 with 68Ga were performed. In these experiments, altogether 34 samples of PSMA-11 were labeled and subjected to radiochemical purity test. All the samples were compared with the standard for [68Ga]PSMA-11. In more than 20 samples radiochemical yields (RCY) exceeded 90 % and in only 5 samples the RCY dropped below 50 %. Table 1 shows average values of pH, activity, retention times (RT) and radiochemical yields (RCY) with standard deviations (STDEV) for samples of 68Ga-labeled PSMA-11 in 0.1M NaHCO3. ![Tab. 1. Results for labeling of PSMA-11 – average values of pH, activity, retention times (RT) and RCY with standard deviations (STDEV)][1] Tab. 1. Results for labeling of PSMA-11 – average values of pH, activity, retention times (RT) and RCY with standard deviations (STDEV) **Conclusion** A new method of labeling PSMA-11 ligand with 68Ga in 0.1M NaHCO3 (pH = 8.5) using Oasis MCX cartridges was developed and tested. The results demonstrated that the method is straightforward, rapid (the whole process of labeling takes 10–15 min) and reproducible. [1]: https://conferences.iaea.org/indico/event/177/abstracts/13828/attachments/8632/Tab._1._Results_for_labeling_of_PSMA-11_-_average_values_of_pH_activity_retention_times_RT_and_RCY_with_standard_deviations_STDEV_1.png
Membrane interacting peptides as positron emission tomography (PET) based infection imaging probes - JYOTSNA BHATT MITRA (BHABHA ATOMIC RESEARCH CENTRE)
Membrane interacting peptides as positron emission tomography (PET) based infection imaging probes
- JYOTSNA BHATT MITRA (BHABHA ATOMIC RESEARCH CENTRE)
23:44 - 23:59
Membrane interacting peptides as positron emission tomography (PET) based infection imaging probes ------------------------------------------------------------------------ Jyotsna Bhatt Mitra, Archana Mukherjee, Mukesh Kumar, Ashutosh Dash **Abstract Objective:** Ubiquicidin (UBI) or ribosomal protein S30 (RS30) is a result of post-translational processing of a 133-amino-acid fusion protein Fau, consisting of an N-terminal 74-amino-acid polypeptide FUBI and the C-terminal 59 amino acid RS30 polypeptide also known as Ubiquicidin. Fragments derived from the RS30/ubiquicidin are known to detect bacteria *in-situ*. UBI (29-41) has been labeled with $^{99m}$Tc as well as $^{68}$Ga and $^{18}$F in order to develop single photon emission computed tomography (SPECT) agent and positron emission tomography (PET) based infection imaging agents respectively. A smaller fragment UBI (31-38) is also reported to show uptake in infectious foci. We set out to compare the potential of radiolabeled UBI (29-41) and UBI (31-38) fragments as PET based infection imaging probes with the aim of improving the sensitivity of detection. **Methodology:** To facilitate $^{68}$Ga labeling, 1,4,7-triazacyclononane-1-glutaric acid-4,7-diacetic acid (NODAGA) conjugated peptide fragments UBI (29-41) and UBI (31-38) were utilized in the current study. Interaction of peptide conjugates was studied with bacterial as well as mammalian membranes models using isothermal titration calorimetry (ITC) and circular dichroism (CD). These peptide conjugates were labeled with $^{68}$Ga in order to develop PET based infection imaging agent and tested for radiochemical purity (RCP), serum stability and in-vitro association with bacteria. Bio-distribution of the $^{68}$Ga labeled peptides was carried out in mice bearing infection to understand the pharmacokinetics of these agents. Results and discussion: Both peptides selectively interacted with bacterial membrane model (anionic) and not with mammalian (neutral) membrane models. UBI (29-41) interacted more strongly with bacterial membrane model as compared to the octapeptide UBI (31-38). Stronger interaction of UBI (29-41) with bacterial membrane model could be explained by greater propensity to form helix in a “membrane like environment”. Both peptide conjugates could be labelled with $^{68}$Ga, with high RCP. $^{68}$Ga labeled peptide conjugates were found to be comparable in terms of in-vitro association with bacteria and bio-distribution in mice bearing infection. **Conclusion:** Our results indicate that NODAGA-UBI (29-41) was superior to NODAGA-UBI (31-38) with respect to binding to bacterial membranes.
Methods of Integration of Radio Cu64 label in Luminescent Copper Nano clusters for Pre and Intra operative Imaging and Therapy of Pancreatic Cancer - SONY GEORGE (HEAD, DEPARTMENT OF CHEMISTRY, UNIVERSITY OF KERALA)
Methods of Integration of Radio Cu64 label in Luminescent Copper Nano clusters for Pre and Intra operative Imaging and Therapy of Pancreatic Cancer
- SONY GEORGE (HEAD, DEPARTMENT OF CHEMISTRY, UNIVERSITY OF KERALA)
23:44 - 23:59
Illustrates our attempt to integrate radio imaging modality via incorporating radio cu64 on to luminescent Cu nano clusters synthesized using BSA ( Bovine Serum Albumin) and HSA ( human serum albumin). The Cu64 [Cu nano clusters] are further conjugated with Erlotinib , a EGFR receptive drug to attribute targeting ability to the tracer cluster towards pancreatic cancer cells. In addition, the radioactive copper moiety cu64 is a dual edged sword by virtue of being a positron as well as electron emitter (deliver a selective cytotoxic dose of beta radiation) there by acting as theranostic agent. Cu nano cluster enveloped by BSA circumvents the challenges created by trans chelation and detachment of cu64. The affinity of the probe on the targets was assessed in invitro studies with PAN C 1 cell lines. The developed integrated imaging dual modality is expected to improve intra - operative assessment of pancreatic tumor demarcation. Cu64 PET probes can be employed for preoperative assessment of pancreatic cancer lesions. PET probes coupled with luminescent copper nano clusters can be employed for enhanced visual imaging modalities which are quite requisite for accurate delineating cancer lesions in the emerging era of robotic surgery.
Nucleophilic synthesis of 6-[18F]fluoro-L-DOPA via copper mediated radiofluorination - Raisa Krasikova (N.P. Bechtereva Institute of Human Brain, Russian Academy of Science)
Nucleophilic synthesis of 6-[18F]fluoro-L-DOPA via copper mediated radiofluorination
- Raisa Krasikova (N.P. Bechtereva Institute of Human Brain, Russian Academy of Science)
23:44 - 23:59
**Background and objectives** Radiopharmaceuticals for positron emission tomography (PET) bearing electron rich [18F]fluorinated arenes are still in limited use as the direct introduction of [18F]fluoride via commonly used SNAr is not suitable. Recently, several transition metal-mediated labeling strategies were have been introduced, to address this problem. Among them radiofluorination of pinacol esters of arylboronic acids (ArylBPin) mediated by copper triflate complex with pyridine (Tredwell at al., 2014) is one of the more promising synthetic avenues under development. This new methodology allows facilitate access to clinically relevant radiotracers, 18F-ring fluorinated aromatic amino acids, drug-like molecules and others. However, implementation of the copper-mediated fluorination in automated synthesizers remains a challenging task. Several studies indicated that the choice of phase-transfer catalyst (PTC) and corresponding base used for the generation of reactive [18F]fluoride species has a profound impact on the 18F-fluorination fluorination of base-sensitive ArylBPin precursors. Here we introduce a new 18F-processing protocol using tetrabutylammonium triflate (TBAOTf) as a neutral PTC and its application in the preparation of 6-[18F]fluoro-L-DOPA via copper-mediated fluorination of commercially available ArylBPin precursor. **Methodology** Radiolabeling precursor, 3,4-OMOM-6-(BPin)DOPA(Boc2)-OtBu (Fig.1), was kindly provided by ABX, Germany. Aqueous [18F]fluoride was loaded onto QMA carb SepPak cartidge (46 mg) from the male side, the cartridge was rinsed by 1.5 mL of i-PrOH and dried with helium. 18F was eluted in the opposite direction using a solution of 12.5 µmol of TBAOTf in 0.6 mL i-PrOH directly to a solution of 5 µmol of Cu(OTf)2Py4, 8 µmol of labeling precursor in 0.3 mL DMA. The mixture was heated in a sealed vial at 110°C for 15 min under air. After intermediate purification (two C18 SepPak cartridges in a series) and acid hydrolysis the crude 6-[18F]fluoro-L-DOPA was purified by HPLC: RP-Amide, Supelco, 250 x 10 mm, NaOAc 10 mM + AcOH 50 mM + 0,1 g/l ascorbic acid; flow 4 ml/min; Rt 9 min. **Results and discussion** First, developed 18F-processing protocol allowed eliminate conventional azeotropic drying step and facilitate automation. The use of TBAOTf as a PTC provides a high 18F-elution efficiency (up to 90%) and radiochemical conversion of 83±6 (n=7) as determined by radioTLC. The desired tracer was obtained in a RCY of 20% (non-optimized, corrected for decay), radiochemical purity > 97% and enantiomeric purity > 98% within 80 min synthesis time. Notably, the suggested procedure employed reduced amounts of expensive precursor (8 µmol) and Cu-catalyst (8 µmol). Work is now in progress to optimize hydrolysis and purification conditions to increase isolated radiochemical yield. **Conslusion** The suggested novel 18F-processing protocol enables the simple and efficient production of 6-[18F]fluoro-LDOPA from commercially available ArylBPin precursor avoiding time consuming solvent evaporation steps. This method can be further extended for the preparation of other 18F-ring fluorinated amino acids.
Nucleophilic synthesis of [18F]FDOPA by using an automated module : A summary of the results of 18 batches - Raviteja Nanabala
Nucleophilic synthesis of [18F]FDOPA by using an automated module : A summary of the results of 18 batches
- Raviteja Nanabala
23:44 - 23:59
**Background** 6-[18F]Fluoro-L-DOPA, ([18F]FDOPA) or simply FDOPA is a radiopharmaceutical used for targeting dopamine receptors by using positron emission tomography. FDOPA is useful for differential diagnosis of Parkinson's disease and other degenerative disorders of the central nervous system. FDOPA PET is also useful for detection and staging of endocrine and brain tumors. FDOPA is conventionally produced via electrophilic substitution by using fluorine-18 prepared by irradiating neon gas using deuteron beam. However, results in the production of low specific activity tracer. Nucleophilic substitution reaction using fluoride has been developed for the synthesis of FDOPA which results in the production of high specific activity tracer. Cassette based synthesis in automated module using novel precursors are now commercially available. Considering the high demand for FDOPA, we are routinely carrying out the production of FDOPA under GMP. The results are presented in this paper. **Methodology** No carrier added 18F was produced by 11 MeV Siemens HP cyclotron. Production of FDOPA was carried out using NEPTIS automated synthesizer procured from Neptis, Belgium installed in clean room with class B area. Radioactivity measurements were done using capintec dose calibrator. Oxygen-18 enriched water and FDOPA cassettes, including all chemicals were procured from ABX, Germany. The precursor (S)–N-Trityl–5–formyl-4-methoxy-methylene-2-nitro-phenylalanine tert-butyl ester is used in the cassette in addition to all other chemicals and purification cartridges. TLC was performed using AR2000 TLC scanner procured from Erkect and Ziegler. The mobile phase used for TLC is glacial acetic acid and methanol (9:1). Residual solvents were analyzed by Agilent Gas chromatography. **Results and discussion** The FDOPA was prepared in four step synthesis in a Neptis synthesizer. Followed by the steps of nucleophilic fluorination, oxidation of intermediates and hydrolysis, FDOPA was trapped on HR-P cartridge and eluted with phosphate buffer, passed through a C-18 and Oasis Wax cartridges to remove non-polar and solid impurities. The product is collected in a 30 mL vial connected to a 0.22  millipore filter. The above series of purification avoids the need for HPLC purification. The total duration of FDOPA production was 90 minutes. The radiochemical yields of FODPA (n=18) are 6 ± 1.2% (decay uncorrected) and 10.5 ± 2.2% (decay corrected). The radiochemical purity was always >94 % and 97.2±1.6 % (n=18) and was retained > 92% upto 7 h. FDOPA was used in multiple nuclear medicine departments for PET-CT and PET-MR studies. The images were found to be highly useful for clinical evaluation of patients suffering from neurological disorders as well as neuroendocrine tumors. **Conclusion** Consistent production of FDOPA was achieved using a cassette based nucleophilic synthesis in a Neptis automated synthesizer under GMP conditions. Though the final decay uncorrected yields were low (~6%), the product was found to be clinically useful for PET-CT and PET-MR studies.
Optimization of the automatic synthesis of 16α-[18F]fluoroestradiol in the SYNTHRA RNplus Research Module - Pía Pereira (Facultad de Química, UdelaR)
Optimization of the automatic synthesis of 16α-[18F]fluoroestradiol in the SYNTHRA RNplus Research Module
- Pía Pereira (Facultad de Química, UdelaR)
23:44 - 23:59
Introduction: 16α-[18F]-fluoroestradiol ([18F]FES) is used for estrogen receptors imaging in breast cancer diagnosis and follow up. Although reported methods use similar labelling procedures, optimal hydrolysis and purification conditions may be different according to the module used. No data referring SYNTHRA RNplus Research Module were found in the literature. Objective: The aim of the present study was the optimization of the automatic synthesis of [18F]FES using the SYNTHRA RNplus Research platform. Methodology: Synthesis of ([18F]FES) was achieved by reaction of 1 mg of 3-O-methoxy-methyl-16β-epiestriol-O-cyclic sulfone in 1 ml of anhydrous acetonitrile with 37 GBq of [18F]F at 100°C for 10 min (Fig. 1). The product was hydrolyzed at 100°C for 12 minusing different conditions: 1) 1.0N HCl, 2) 2.0N HCl in acetonitrile: water (3.0 ml, 9:1 v/v) and 3) 0.5N H2SO4 in ethanol: water (3.0 ml, 9:1 v/v). Purification was performed by HPLC using a C18 column (VP250/10 SynthraReeperbahn, 5 μm) flow rate: 2.0 ml/min, λ=280 nm, using either a) Ethanol: water 50:50 or b) Water: Etanol: Acetonitrile (50:25:25) as mobile phases. The peak was either diluted with 0.9% NaCl (a) or with 50 ml of water and purified with a Sep-Pak C18 Plus-Light cartridge (b). The radiochemical purity (RCP) was determined by HPLC using a Phenosphere column (ODS 80 A, 250x4.6 mm, 5 μm), flow 1.5 ml/min. and a gradient of acetonitrile in water (acetonitrile 10% to 90% from 0 to 10 min) and λ=280 nm. Results and discussion: The module contains a reduced volume reactor (7 mL, conical shape) to perform the labelling and a standard reactor for the hydrolysis. Synthesis of ([18F]FES) was developed by a standard procedure and the labelling yield (aprox. 25%) was similar to reported data. Hydrolysis and purification are the critical steps and different conditions were assayed in order to optimize the RCP of the product. Hydrolysis can be performed either using HCl or H2SO4. The use of H2SO4 led to the formation of less impurities and consequently was selected for further experiments. Purification was developed by preparative HPLC. The selection of ethanol as only organic solvent offers the advantage of the simplicity of the final conditioning. However, this condition led to poor RCP (<90%). The use of a mixture of ethanol and acetonitrile, on the other hand, required an additional step of solid phase extraction but rendered a RCP of aprox. 100% In all the syntheses, the pH was in the range 5.0-6.0, the residual Kryptofix® was below the limit and the residual solvents (acetone, acetonitrile and ethanol) met the specifications. Conclusion: The synthesis of [18F]FES was optimized in a SYNTHRA RNplus Research platform. The best hydrolysis condition was the use of 0.5N H2SO4 in ethanol: water (3.0 ml, 9:1 v/v) and the purification by HPLC using Water: Etanol: Acetonitrile (50:25:25) as mobile phase followed by solid phase extraction to remove acetonitrile. Acknowledgments: ANII (POS_FCE_2018_1_1007787)
Potential radiotracers based on the 4’-O-methylhonokiol structure for PET visualization of neuroinflammation - Natalia Gomzina (N.P. Bechtereva Institute of Human Brain, Russian Academy of Science)
Potential radiotracers based on the 4’-O-methylhonokiol structure for PET visualization of neuroinflammation
- Natalia Gomzina (N.P. Bechtereva Institute of Human Brain, Russian Academy of Science)
23:44 - 23:59
**Introduction** Neuro-inflammatory processes are known to underlie the mechanism of neuronal damage and play a key role in the neurodegenerative disease progression. The cyclooxygenase 2 (COX-2) enzyme is one of the most studied neuroinflammatory biomarkers and an attractive target for PET imaging. Neolignan 4’-O-methylhonokiol (MH) isolated from Magnolia officinalis, has high anti-inflammatory activity and selectively inhibits the expression of COX-2 with IC50=0.062 μM, as was recently shown by Kim H.S. et.al., 2015. Here we report the synthesis of novel labeled MH derivatives ([11C]MPbP and [18F]FEtPbP) and their preliminary evaluation on the lipopolysaccharide (LPS)-induced neuroinflammation rat model. [Pic 1][1] **Methods** The MH derivatives [11C]MPbP (4'-[11C]methoxy-5-propyl-1,1'-biphenyl-2-ol) and [18F]FEtPbP (4'-(2-[18F]fluoroethoxy)-2-hydroxy-5-propyl-1,1'-biphenyl) were obtained by 11C-methylation and 18F-fluoroethylation of the precursor with Boc-protecting group using synthons [11C]CH3I and [18F]FCH2CH2Br, respectively. After HCl hydrolysis of intermediates the crude reaction mixtures were purified by semi-preparative HPLC. Neuroinflammation in rats was induced by an intraperitoneal injection of LPS from E.coli (2 mg/kg) before 24 h the administration of [11C]MPbP, [18F]FЕtPbP, celecoxib or placebo into the tail vein (0.1-0.2 mCi/0.5 ml of phosphate buffer pH 7.4, containing ethanol (5-7%, v/v)). Сelecoxib, а well-known non-steroid anti-inflammatory drug and a selective inhibitor of COX 2 was used as a reference. Ex vivo radioligand biodistribution was performed by direct radiometry of organs and tissues samples. The uptake of radioactivity was determined by the dose administered per gram of tissue (% ID/g). **Results and discussion** [11C]MPbP and [18F]FЕtPbP were obtained in decay-corrected isolated radiochemical yields 20 and 35 % based on the activity of the corresponding alkylating agent. The biodistribution data showed that the observed uptake in the brain of neuroinflammatory rats was 4 times higher than it was in intact animals. In addition, it was shown that [11C]MPbP оr [18F]FЕtPbP increased uptake occurred in the parts of rat brain where COX-2 expression was observed (pons&medulla). A decrease in the radiotracer uptake by 2-3 times in these regions with the celecoxib pretreatment may serve as evidence of this hypothesis. **Conclusion** Synthesis of [11C]MPbP and [18F]FEtPbP, labeled MH analogs has been developed. On the rat neuroinflammation model, it has been shown that these radiotracers have the potential for PET imaging of neuroinflammation. This study was funded by RFBR according to the research project 17-04-02119 A. [1]: https://cloud.mail.ru/public/Cmid/4wr4uoKyg
Preclinical evaluation of the theranostic 68Ga/177Lu-[DOTA-CXCR4-L] pair - Myrna Luna-Gutiérrez (INSTITUTO NACIONAL DE INVESTIGACIONES NUCLEARES)
Preclinical evaluation of the theranostic 68Ga/177Lu-[DOTA-CXCR4-L] pair
- Myrna Luna-Gutiérrez (INSTITUTO NACIONAL DE INVESTIGACIONES NUCLEARES)
23:44 - 23:59
Background The chemokine-4 receptor (CXCR4) is overexpressed in more than 23 types of human cancers that metastasize to distant organs. In the progression of breast cancer and its metastases, the overexpression of CXCR4 has been demonstrated in 90% of triple-negative breast cancer tumors Objective To prepare and evaluate the in vitro and in vivo ability of 68Ga-CXCR4-L and 177Lu-CXCR4-L ligands to target the CXCR4 protein in glioblastoma and triple-negative breast cancer cells. Methodology 68Ga labeling was performed by adding 1 M acetate buffer (pH 4.0) and gallium-68 chloride obtained from a 68Ge/68Ga generator (ITG, Germany) to a lyophilized formulation containing the cyclo(D-Tyr-D-[NMe]Orn(HYNIC-DOTA)-Arg-NaI-Gly) ligand [DOTA-CXCR4-L] followed by incubation at 95°C for 10 min. For 177Lu labeling, 1 M acetate buffer (pH 5.0) and lutetium-177 chloride (ITG, Germany) were added to a lyophilized vial containing the DOTA-CXCR4-L following by incubation at 95°C for 30 min. The radiochemical purity was evaluated by reversed-phase HPLC and ITLC-SG analyses. Stability studies in human serum were performed by size-exclusion HPLC. In vitro and in vivo cell uptake was tested using human breast cancer cells (triple-negative DU-4475) and human glioblastoma cells (U87MG) with blocked and non-blocked receptors. Images were obtained in athymic mice with induced DU 4475 or U87MG pulmonary micrometastasis by using a micro-SPECT/PET/CT system. Results and discussion 68Ga-DOTA-CXCR4-L and 177Lu-DOTA-CXCR4-L obtained with radiochemical purities of 95% and 99%, respectively, showed high stability in human serum and specific in vitro and in vivo recognition in glioblastoma and triple-negative breast cancer cells. Using pulmonary micrometastasis DU-447 and U87MG models, a clear uptake of both radiopharmaceuticals was observed. Conclusions The results obtained in this study warrant further preclinical studies to evaluate therapeutic efficacy of 177Lu-DOTA-CXCR4-L, as well as dosimetry and clinical studies to determine the specificity and sensitivity of 68Ga-DOTA-CXCR4-L to target the chemokine-4 receptor in different kind of tumors. Acknowledgment This study was supported by the Mexican National Council of Science and Technology (“Laboratorios Nacionales” and CONACyT-SEP-CB-2018, A1-S-36841). References [1] Lefort et al. (2017) Oncogene 36: 1211. [2] Chu et al. (2010) J Surg Res 159: 689. [3] Chittasupho et al. (2017) Eur J Pharm Biopharm 119: 310. [4] Luker et al. (2012) Oncogene 31: 4750.
Preparation of 177Lu-DOTA-Trastuzumab: an insight into the in-house optimized radiochemistry procedures employed for patient dose preparation - Mohini Guleria (Bhabha Atomic Research Centre)
Preparation of 177Lu-DOTA-Trastuzumab: an insight into the in-house optimized radiochemistry procedures employed for patient dose preparation
- Mohini Guleria (Bhabha Atomic Research Centre)
23:44 - 23:59
Objective: Trastuzumab (Herceptin®), a humanized monoclonal antibody, is an approved agent used for immunotherapeutic treatment of metastatic breast cancer as it targets HER2 (human epidermal growth receptors 2) receptors over-expressed in such cancer cells. Therefore, radiolabeled Trastuzumab is expected to have significant potential as a radioimmunotherapeutic agent for the treatment of ca breast patients over-expressing HER2 receptors. The aim of the present study is to standardize the formulation protocol of $^{177}$Lu-Trastuzumab and scale-up the preparation for administration in patients. Methodology: Trastuzumab was conjugated with a suitable bi-functional chelating agent (BFCA) namely, p-NCS-benzyl-DOTA by incubating Trastuzumab (5 mg, 35 nmol) and p-NCS-benzyl-DOTA (190 μg, 350 nmol) in sodium carbonate buffer (pH=9.5, 0.2 M) at 37 °C for 17 h. Post-incubation, the reaction mixture was purified using Amicon ultra-centrifugal units (MW cut off 10kDa) using NaOAc buffer (pH=5.0, 0.2 M). Determination of average number of p-NCS-benzyl-DOTA molecules attached per antibody moiety was carried out by UV-Vis spectrophotometry as well as by mass spectrometry using MALDI-TOF technique. $^{177}$Lu-Trastuzumab complex was prepared by incubating the purified Trastuzumab-BFCA conjugate (2 mg, 13 nmol) with $^{177}$LuCl$_{3}$ [150 μL, 80 mCi (2.96 GBq)] at 37 °C for 90 min at pH ~5.5. Percentage radiolabeling yield (%RCY) of the radiolabeled formulation was determined by paper chromatography (PC) using 0.1M sodium citrate solution as the mobile phase and high performance liquid chromatography (HPLC) using 0.05 M phosphate buffer with 0.05% sodium azide as the mobile phase. The radiolabeled preparation was purified by PD10 desalting columns using 0.2 M NaOAc buffer as the eluting solvent. The stability of the purified $^{177}$Lu-Trastuzumab complex was determined till 4 days post-preparation by incubating the complex in phosphate buffered saline (PBS) at room temperature and carrying out the quality control analyses following the procedures mentioned above at various time intervals. The purified $^{177}$Lu-Trastuzumab formulation was administered in 08 ca breast patients [~5 mCi (185 MBq) in each patient] for studying preliminary pharmacokinetics and biological distribution of the agent. Results and Discussion: An average of 7.5±1.2 p-NCS-benzyl-DOTA molecules were found to be attached per Trastuzumab moiety. HPLC studies showed that the $^{177}$Lu-Trastuzumab conjugate could be prepared with a %RCY of 75.78±3.56 (Rt = 15.5 min and 21.5 min for $^{177}$Lu-Trastuzumab and free $^{177}$LuCl$_{3}$, respectively), which was subsequently improved to >95 by purification through PD10 column (with average recovery of 72.8±1.2%). In-vitro stability studies showed that the %RCY of $^{177}$Lu-Trastuzumab decreased to 84.15±1.57 after 4 days of storage at room temperature in PBS. Clinical studies in ca breast patients revealed the accumulation of the radiolabeled antibody at breast cancer lesions with slow but gradual clearance of activity from blood and other non-target organs. Conclusion: An in-house procedure for the formulation of patient dose of $^{177}$Lu-Trastuzumab was optimized. Preliminary clinical imaging studies revealed the retention of affinity of Trastuzumab towards the disease after functional modifications and radiolabeling procedures.
Preparation of Single Patient Dose of Lu-177-DOTA-Rituximab – Using Low Specific Activity Lu-177-Chloride - Avik Chakrabotry (Radiation Medicine Centre, BARC, Mumbai, India)
Preparation of Single Patient Dose of Lu-177-DOTA-Rituximab – Using Low Specific Activity Lu-177-Chloride
- Avik Chakrabotry (Radiation Medicine Centre, BARC, Mumbai, India)
23:44 - 23:59
**Background:** Limited access to high specific activity Lu-177 in India and its prohibited cost provide the necessary impetus for the present work on development of Lu-177-DOTA-Rituximab using low specific activity Lu-177 Based on the advantageous/favorable nuclear properties of Lu-177 over the I-131, the development of Lu-177-DOTA-Rituximab was obviously pertinent. Towards this we attempted to optimize the radiolabeling of Lu-177-DOTA-Rituximab using low specific activity(<15 mCi/µg) and carrier added Lu-177-Chloride. The physicochemical, biological quality control parameters, *in-vitro* stability, immunoreactivity and cell binding studies carried out in Daudi cell-lines. *In-vivo* biodistribution studies were carried out in suitable animal model. **Methodology:** Lu-177-Chloride produced at our research reactor. Rituximab(10mg/mL) pre-concentrated from 500µL to 100µL using 30kDa MW cut-off filtration device at 5000rpm for 22minutes. Coupling of rituximab(5mg/100µL, 34.75nM) with p-NCS-benzyl-DOTA(240µg/24µL, 347.56nM) carried out at 1:10 molar ratio incubating at 37degC for 22hr. The conjugated reaction mixture purified using pre-conditioned PD-10. The DOTA-benzyl-Rituximab eluted from PD-10 using 0.2M sodium-acetate buffer(pH~5.5) and its concentration was estimated by Bradford’s assay at 570nm. Prior to radiolabeling, pH of Lu-177-Chloride(285-300mCi in 250-275µL) adjusted to 6.5-7.0 using 0.2M sodium-acetate solution. Lu-177-Acetate incubated with 124µL of DOTA-benzyl-Rituximab at 37degC for 80minutes. After incubation the radiolabeled reaction mixture purified using PD10(pre-conditioned with 0.2M sodium-acetate solution). In-vitro stability of the Lu-177-DOTA-Rituximab was ascertained by adding ascorbic acid(40mg/0.5mL of 0.2M sodium-acetate solution). The RCP was evaluated using TLC-SG{(0.1M sodium-citrate buffer(pH-5.0)} and HPLC(size-exclusion column, 0.05M phosphate-buffer,pH~6.8). Gel-clot BET-assay and sterility test were performed. Human Leukemia cell-line Daudi expressing CD20, used for *in-vitro* evaluation, grown in IMDM with 10%FBS at 37degC. *In-vitro* cell-binding studies performed by incubating Daudi cells in 1mL of internalization buffer(IMDM, 0.2%BSA) containing radioligand(~5pmol peptide) for 15, 30, 60 & 120minutes and washed with PBS. Non-specific internalization assessed by addition of cold rituximab(5nmol). For membrane receptor binding assay, cells homogenates incubated at above time points. Biodistribution studies carried out in Daudi cell-lines xenograft tumor bearing nude mice at 6h, 24h, 48h & 72h intervals and quantified by γ-spectrometer. **Results and Discussions:** Using Lu-177 of low specific activity (< 15 mCi/µg), 60-65mCi of Lu-177-DOTA-Rituximab(single patient-dose) was prepared using ~300mCi of Lu-177-Chloride. Lu-177-DOTA-Rituximab was found to be clear, colorless, pH between 5.5-6.0 and RAC between 8-10 mCi/mL. The RCP of Lu-177-DOTA-Rituximab estimated by TLC was >98% with retention-factor 0.00-0.10. RCP derived by HPLC was >95% with retention-time of labeled-product between 14.5–15.5minutes. EL <6EU/mL, radiopharmaceutical was sterile. *In-vitro* and serum stability of the product indicated stability upto 96hr upon storage at -20degC with stabilizer. Lu-177-DOTA-Rituximab showed rapid binding in Daudi cells(25%), reaching a plateau after 30-60minutes. In biodistribution study, radioactivity decreased from most organs after 24h post-injection. High uptake and long-term retention of radioactivity found in tumor model which corroborates with scintigraphy studies. **Conclusion:** Single patient dose of Lu-177-DOTA-Rituximab could be produced in optimum yield using 12-15 mCi/µg Lu-177. The product compares well with the preparation documented using nca Lu-177. Further studies towards clinical translation of this promising radiopharmaceutical in patient are underway.
Radiolabeled TATE functionalized Gold Nanoparticles for potential use in imaging and therapy of Neuroendocrine tumors - Dheeraj Kumar (Board of Radiation and Isotope Technology)
Radiolabeled TATE functionalized Gold Nanoparticles for potential use in imaging and therapy of Neuroendocrine tumors
- Dheeraj Kumar (Board of Radiation and Isotope Technology)
23:44 - 23:59
Background and Goal of the study Peptide receptor radionuclide theranostics is a targeted approach for imaging and therapy of cancers. In this purview, a number of peptide based derivatives such as octreotide analogues, are in clinical use utilizing 68Ga/177Lu radionuclidic pair. The octreotide peptide such as 3-Tyr-Octreotate (TATE) used for peptide receptor targeting is an agonist peptide which enters the tumor cell via somatostatin receptor mediated transport across the cell membrane. However, rapid elimination of the radiopharmaceutical from blood limits the uptake of the radiopharmaceutical in the tumours. To effect improved target uptake, there is an interest to explore the performance of radiolabeled TATE functionalized gold nanoparticles, as the later are known to have higher blood residence period. Surface modified gold nanoparticles are known to enter living cells and are excellent candidate for utilization in biomedicines, mainly in cancers and carcinomas. The objective of the present work is to functionalize gold nanoparticles with TATE peptide along with DOTA chelator so as to radiolabel them with 68Ga/ 177Lu radionuclides and evaluate them for their theranostic potential. Methodology Commercially available DOTA-TATE was directly used to functionalize Gold nanoparticles. Briefly, DOTA-TATE (0.7 mM, 0.5 mL) solution in water was added and mixed with a solution of HAuCl4 (1mM) in TWEEN 80 (1mM). The resulting solution was then reduced rapidly with ice-cold NaBH4 (0.5 M, 1mL) to obtain the required ‘TATE along with DOTA functionalized gold nanoparticles’. The obtained gold nanoconjugates were purified by dialysis, characterized and then used for labelling studies. The labelling protocol involved direct addition of purified gold nanoparticles to 68GaCl3/177LuCl3 activity (185 MBq) in 0.1M acetate buffer (pH 4-5), and the resulting reaction mixture was heated at 60°C for 15-30 min to yield the radiolabeled TATE functionalized gold nanoparticles. Results and Discussion TATE having a disulphide linkage is expected to have affinity towards Au surface under reducing conditions. Such a formation was observed in the present experimental conditions and gold nanoparticles in wine red colour were obtained. The nanocolloidal solution using UV/Vis Spectroscopy gave a prominent peak at 512nm, thus confirming the nano-colloidal nature of the particle synthesized with size in the range 10-20 nm. The radiolabeling yield as determined by paper chromatography in 0.5M citrate buffer [Rf free MCl3 (M=68Ga/ 177Lu) =0.8-1.0; TATE functionalized Au-nanoparticle = 0-0.2] was observed to be >90 % for both the radiometals. In vitro experiments in AR42J cell lines are underway to evaluate the potential of the functionalized gold nanoparticles in comparison with the DOTA-TATE metal complexes in clinical use. Conclusion Water dispersible Gold NPs functionalized with TATE peptide along with DOTA chelator has been successfully synthesized. These have been successfully labelled with radiometals in reasonable yields. Further cell experiments are underway to evaluate the efficacy of the labelled Au nanoparticles.
Radiolabeled peptidomimetic inhibitor of the VEGF/NRP-1 complex for the imaging of malignant tumours - preliminary research - Katarzyna Masłowska (Institute od Nuclear Chemistry and Technology)
Radiolabeled peptidomimetic inhibitor of the VEGF/NRP-1 complex for the imaging of malignant tumours - preliminary research
- Katarzyna Masłowska (Institute od Nuclear Chemistry and Technology)
23:44 - 23:59
Background: The widest possible range of available molecular targets and their vectors is a crucial key for targeted diagnosis and cancer therapy problems. The presented work concerns a vector – the peptidomimetic inhibitor, the molecular target of which is neuropilin-1 (NRP-1). NRP-1 is a receptor for the vascular endothelial growth factor-165 (VEGF165) playing an important role in pathological angiogenesis and in tumor development and progression. It has been observed that NRP-1 overexpression is associated with tumor aggressiveness in several types of cancers. The demonstrated involvement of VEGF165/NRP-1 complex in pathological angiogenesis has catalyzed interest in searching for inhibitors of such interaction to combat angiogenesis dependent diseases. It was shown before that a heptapeptide Ala-Thr-Trp-Leu-Pro-Pro-Arg (A7R) is a good inhibitor of the VEGF165/NRP-1 interaction. Aim: The work involved the labeling of the Lys-(hArg)-Dab-(Ahx-DOTA)-Pro-Arg peptide (working name *KM1*) and preliminary physicochemical studies of obtained radiobioconjugate (Figure 1). *KM1* is an analog of the A7R peptide what is stronger inhibitor of VEGF165/NRP-1 complex than A7R. ![enter image description here][1] Figure 1. Structure of 68Ga-DOTA-KM1 radiobioconjugate. Methodology: Peptide *KM1* was synthesized in the Peptides Laboratory of the University of Warsaw using the SPPS method on Wang resin using the Fmoc strategy. The labeling was performed with 68Ga (95°C, 10 min) and the obtained radiobioconjugate was purified by HPLC (semi-preparative Jupiter® Proteo column). Lipophilicity (logP value) was determined in a standard biological system (PBS solution and *n*-octanol) and the stability of the compound was tested in human serum. Results and discussion: The labeling yield was about 72%. The determined logP value equal to -4.16 ± 0,02 indicates that 68Ga-DOTA-KM1 radiobioconjugate is a strongly hydrophilic compound. Stability studies in human serum showed that about 85% of the radiobioconjugate remains in the free form in the serum solution (about 15% is combined with the protein present in the serum). Conclusion: The presented studies are the first step on the new VEGF/NRP-1 radioisotopically labeled peptidomimetic inhibitors for cancer diagnostics and therapy. In the next steps the syntheses of new peptidomimetics are planned as well as the using of a long-lived isotope, e.g. 177Lu or a 43,44Sc/47Sc theragnostic pair. [1]: https://lh3.googleusercontent.com/2qvBJ-w_uebkCXgCFW1_7tAGi76oZyi7RjchVjhWDXHiAs7mA8r-npk8em5ezrGj9YsacwzmK9Q7Ev5NymJ9PTy8CBHUmAmiopR8Ey_Jop3XBZ8pp_iJUhwAf-w8AcdXx3VlMmOODtbwh_-i-oLIhowpZGibTfNnZSrRLQZsfO2zrUUsjHQUUbZD8qGX2BFFRs3itl66TYNyVwr8BnDr26Bx7yY6OEcrL7tYd2hZHUvtIM1A1HJIOsT0EbsVaRuvq3wOeJZ4sldJkSxmi7H169cVjRYCWmDviMMJbBy6sMYQQu8yUyFFfIgdS3XKo44rSNYdiTAqTh-ik-E2wvNHu_oUeToVsW70tm05MBH23TUXeYppMU7PGPUTsu-IQd6kyPlepToIsV8QerFFdXklHllvCwQgtulwYpIuMSJX27Mjlk2xfkP93vdU-8Vi71xG9imcbRDmL0i0S-nmz1TnhCWr6wspXCp1uip7F_3h-ViOo4vmnXtJWTMWs5k9TTtKrnhgD-SgFCIrRiCIibyyHttCiW0vQ1GCOdQXOQPVhVss6WOkfAIjNNF3ebBGGBoDCEWU8_N_oZttcUMTY9MaMlpGEN5f2zOSqR9m_vvyNCA9wBIjILlIb0n6-UapoyuC0ga-DO32x3wST_VkueMoZVnrB_o1Jwo=w256-h258-no
Recent advances in Ga-68 Radiopharmaceuticals and Ga-68 Bisphosphonates for the theranostic management of Neuroendocrine tumours. - VIJAY KUMAR (Westmead Hospital, The Children's Hospital at Westmead & Sydney Medical School, Sydney University)
Recent advances in Ga-68 Radiopharmaceuticals and Ga-68 Bisphosphonates for the theranostic management of Neuroendocrine tumours.
- VIJAY KUMAR (Westmead Hospital, The Children's Hospital at Westmead & Sydney Medical School, Sydney University)
23:44 - 23:59
BACKGROUND/GOAL/Objectives of the Study: Renaissance of 68Ga-labelled peptides has given new dimension to theranostic imaging of Neuroendocrine Tumors and Prostate Cancer. The outstanding success of 68Ga-labelled agents in the last decade is primarily due to availability of reliable, long-lived 68Ge/68Ga Generators, extensive automation, development of new macrocyclic linker based 68Ga chemistry, and a huge amount of clinical data in a short time. METHODOLOGY: Somatostatin receptors are over-expressed in neuroendocrine tumours such as pituitary adenoma, neuroblastoma and small cell lung carcinoma etc. These tumours are diagnosed with 68Ga-DOTA-TATE and are effectively treated with 177Lu-DOTA-TATE. The huge success in the management of neuroendocrine tumours led to rapid development in theranostic approach for prostate cancer mamagement, as there was no specific diagnostic or treatment tool available prior to this agent. Urologists, endocrinologists and oncologists were very excited and they passed on the benefits to the patients, the ultimate winners. RESULTS & DISCUSSIONS: Availability of ionic 68Ga from the 68Ge/68Ga generator is the key to the recent developments. Equally important is the development of macrocyclic linkers such as DOTA, NOTA etc. The ability of these linkers enabled the scientists to radiolabel a large number of ligands for clinical applications. The most extensively used agents are 68Ga-DOTA-TATE for neuroendocrine tumours, and 68Ga-PSMA for prostate cancer. The bifunctional chelators such as DOTA and NOTA were shown to bind 68Ga and 177Lu with equal efficiency and offered kinetic stability and thermodynamic stability, which is the under-pinning success for theranostic developments in the last decade. New approaches are developed for Therapy, which includes combined PRRT (with other treatment modalities) such as Chemotherapy (Capecitabine, Doxorubicin), Kinase inhibitors (Sunitinib, Sorafenib), intraoperative use of probes after PRRT with 177Lu and applications. Alpha emitters (eg. 225Ac, 213Bi, and 223Ra) were shown to be highly effective. Frank Roesch’s group have shown that Bisphosphonates were good theranostic agents to deliver beta radiation to the bones and soft-tissues to augment therapeutic efficacy. CONCLUSION: Recent developments in “Theranostic approach” are the BEST thing to happen in nuclear medicine in the past decade. They have created extensive enthusiasm around the world to apply this technology for the benefit of the patients.
Synthesis and preclinical evaluation of 64Cu-NOTA-HYNIC-iPSMA - Blanca Ocampo-García (Instituto Nacional de Investigaciones Nucleares)
Synthesis and preclinical evaluation of 64Cu-NOTA-HYNIC-iPSMA
- Blanca Ocampo-García (Instituto Nacional de Investigaciones Nucleares)
23:44 - 23:59
Synthesis and preclinical evaluation of 64Cu-NOTA-HYNIC-iPSMA Blanca Ocampo-García, Guillermina Ferro-Flores, Myrna Luna-Gutiérrez and Clara Leticia Santos-Cuevas Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos, CONACyT. Instituto Nacional de Investigaciones Nucleares, Estado de México, MEXICO. Background Because of its beta-negative (negatron) and beta-positive (positron) particle emissions, 64Cu is useful for PET imaging and therapy [1]. 99mTc-HYNIC-iPSMA has demonstrated high ability to target tumors over-expressing the prostate specific membrane antigen (PSMA) useful for SPECT imaging [2]. One critical aspect of this molecule is the presence of the HYNIC group acting as an additional lipophilic location for the coupling to the hydrophobic structure of the PSMA enzyme [3]. Taking the advantage of HYNIC-iPSMA to detect prostate tumors, in this research we added NOTA to the molecule to obtain a new 64Cu radiopharmaceutical with theranostic potential. Objective To synthesize and characterize biochemically 64Cu-DOTA-HYNIC-iPSMA as well as to evaluate in mice its potential as a PET imaging agent for PSMA-positive tumors. Methodology The p-SCN-Bn-NOTA (Macrocyclics, USA) was conjugated to the HYNIC-iPSMA ligand (molar ratio 0.95:1) by dissolving the compounds in 0.1 mL of 0.2M NaHCO3 (pH 9.5) and incubated at 37°C for 1 h. After reaction, the sample was diluted to 50 mL using injectable grade water. The solution was filtered by membrane (0.22µm) and fractionated in sterile vials (2 mL and 100 µg of the conjugate per vial). Finally, samples were lyophilized and analyzed by HPLC. The lyophilized vials containing NOTA-HYNIC-iPSMA (purity of 95%) were reconstituted with 1 mL of acetate buffer (1M, pH 5.0) plus 0.5 mL of 64CuCl2 (pH 4) and incubated at 95°C for 10 min. The in vitro evaluation of the obtained radiopharmaceutical was carried out in human serum (stability) and in human prostate LNCaP cancer cells (cancer cell uptake). For PET images a lung LNCaP micro-metastases model in athymic mice was used. Results and discussion HPLC analyses of NOTA-HYNIC-iPSMA showed a high yield of the reaction (99%). Only 5% of HYNIC-iPSMA remained as a chemical impurity. Radio-HPLC analysis showed the formation of 64Cu NOTA-HYNIC-iPSMA with a radiochemical purity of >98%. In vitro studies demonstrated high stability in human serum and a LNCaP cell uptake of 8.3±1.6 % (of the total activity) at 1 h. PET images showed a clear visualization of LNCaP metastases. Conclusions 64Cu NOTA-HYNIC-iPSMA obtained from kit formulations showed high in vitro an in vivo stability in human serum and specific uptake in LNCaP cells with potential as a new theranostic radiopharmaceutical. Acknowledgment This study was supported by the Mexican National Council of Science and Technology (“Laboratorio Nacional de Investigación y Desarrollo de Radiofármacos CONACyT”).
Synthesis of [18F]PSMA-1007 for Imaging Prostate Cancer by using an automated module and clinical studies - Raviteja Nanabala
Synthesis of [18F]PSMA-1007 for Imaging Prostate Cancer by using an automated module and clinical studies
- Raviteja Nanabala
23:44 - 23:59
**Background** Radiopharmaceuticals targeting the enzyme, PSMA over expressed in prostate and other cancers are now widely used in nuclear medicine. 68Ga-PSMA-11 has become a widely accepted tracer for imaging prostate cancer. The nuclear medicine centres which do not have access to 68Ge/68Ga generator are interested in using 18F tracers for imaging prostate cancer. PSMA-1007 is a ligand having molecular structure similar to PSMA-617 which is widely used for 177Lu/225Ac therapy of prostate cancer. We describe here the production of [18F]PSMA-1007 using Neptis Syntheziser and a commercially available cassette. **Methodology** No carrier added 18F was produced in a 11 MeV Siemens HP cyclotron. Production of [18F]PSMA-1007 was carried out using NEPTIS mosaic RS automated synthesizer procured from Neptis, Belgium installed in clean room with class B area. Radioactivity measurements were done using Capintec dose calibrator. Oxygen-18 enriched water and [18F]-PSMA cassettes that include all chemicals were procured from ABX, Germany. The precursor PSMA-1007 was used in the production which was supplied along with cassette by ABX. TLC was performed using AR2000 TLC scanner procured from Eckert and Ziegler. The mobile phase used for TLC is Acetonitrile and Water 60/40 (V/V). Residual solvents were analyzed by Agilent Gas chromatography. Clinical studies were done in patients referred to the nuclear medicine department for PET imaging of prostate cancer. **Results and discussion** The [18F]PSMA-1007 was prepared in two step synthesis. Followed by labelling, [18F]PSMA-1007 was trapped on a preconditioned C-18 cartridge and eluted with 30% ethanol and passed through Chromafix PS-H+ cartridge. The final product was collected through a 0.22  Millipore filter connected to a 30 mL vial. The total duration of [18F]PSMA-1007 production was 45 minutes. The radiochemical yields of [18F]-PSMA-1007 are 28 ± 8% (decay uncorrected, end of the synthesis) and 38 ± 10% (decay corrected to start of the synthesis). The radiochemical purity was always >98 %. [18F]PSMA-1007 was used in multiple nuclear medicine departments. PET-CT images are acquired 2 hour post injection of 200-300 MBq of the radiopharmaceutical in prostate cancer patients. The images were reconstructed with standard software and evaluated by nuclear medicine physicians. PET-CT images were comparable to [68Ga]PSMA-11. Compared to 68Ga-PSMA-11 images some differences in physiological uptake sites of the tracer were noted with [18F]PSMA-1007 images; eg. the consistent tracer uptake in gall bladder owing to the hepatobiliary route of excretion of [18F]PSMA-1007. However, the reporting nuclear medicine physicians appreciated the image quality of [18F]PSMA-1007 images and judged the image quality of [18F]PSMA-1007 images at par with 68Ga-PSMA-11 for imaging prostate cancer. **Conclusion** [18F]PSMA-1007 was prepared in higher yields and in Curie quantities using a cassette based nucleophilic synthesis in a Neptis automated synthesizer under GMP conditions. The synthesis yields were sufficient to deliver the activity to multiple nuclear medicine centres. [18F]PSMA-1007 is a tracer that can be routinely prepared in a cyclotron and distributed to NM centres for assessment of prostate cancer.
Synthesis of m-Iodobenzylguanidine (m-IBG) by solid phase method and its evaluation - ammar CHAREF
Synthesis of m-Iodobenzylguanidine (m-IBG) by solid phase method and its evaluation
- ammar CHAREF
23:44 - 23:59
A. Charef, S.Boudjemai, S.Neffafa and A.Benzaid Draria Nuclear Research Centre, Department of Nuclear Applications, P.O.Box: 43, Route d’El-Achour, Sebbala, Algiers, Algeria. ABSTRACT Meta-iodobenzylguanidine (MIBG) radioiodinated with 123I, and 131I is one of the most important radiopharmaceuticals used in Nuclear Medicine. It’s used for diagnosis and treatment of pheochromacytoma and neuroblastoma, imaging of adrenal medulla, and for studying heart sympathetic nerves. Almost described methods of synthesis of cold meta-iodobenzylguanidine hemi-sulfate are performed in accordance to Wieland and al procedure (1980), by condensation for 4 hours of meta-iodobenzylamine hydrochloride with Cyanamid into an oil bath heated at 100°C. This method seems to be long and difficult to implement for routine production. The objective of this study was to develop an efficient and rapid method for preparation of MIBG. Various experiments in order to reduce the time of the synthesis were carried out by heating in an oven a mixture of meta-iodobenzylamine Hydrochloride and cyanamid at 120°C during several times. The second step was done according to Wieland’s method. We have also studied the effect of the reaction time on the yield of meta-iodobenzylguanidine bicarbonate. Physicals and chemicals properties of synthetized MIBG was evaluated by the determination of melting point, UV-Visible spectrophotometry, spectroscopy IR and HPLC. Results showed high purity of synthesized molecule with yields similar to those obtained by Wieland and al (70%) and purity over 98 % after 30 min of reaction at 120°C. The HPLC analysis of MIBG gives a good retention time. A procedure for radioiodinated of cold m-iodobenzylguanidine with iodine-125 has been developed in our laboratory. Freeze-dried kits prepared from MIBG (synthesized and reference), ascorbic acid and copper nitrate were reconstituted in deaerated distilled water and labeled with 9-18 MBq of sodium iodide (NaI-125). The vials were heated in an oil bath at 100 ° C for 20 minutes. The labeled MIBG kit presents a very high radiochemical purity and a high labeling efficiency. Keywords : MIBG synthesis, MIBG radiolabelling, Wieland. and al (1980), UV-spectrometry, HPLC, radiolabelling, diagnostic imaging, neuroendocrine tumors therapy.
Tc 99m octreotide in Neuroendocrine tumors: a different Radiotracer from traditional 111 In: Our experience. - Mariela Agolti (Centro Medicina Nuclear Clinica Modelo .Parana)
Tc 99m octreotide in Neuroendocrine tumors: a different Radiotracer from traditional 111 In: Our experience.
- Mariela Agolti (Centro Medicina Nuclear Clinica Modelo .Parana)
23:44 - 23:59
**Background:** tumours deriving from cell types expressing somatostatin receptors may be imaged by somatostatin receptor scintigraphy. The most common radiotracer to bind to octreotide is 111 In which is not produced in our country, as well as in other Latin American countries, the cost is very high and the availability of this tracer is rare, and also, its half life is very long, we have stated labeling Octreotide with Tc99m, Which is a more available, cheaper and its short half-life let us work easily. The basic mechanism is the union to receptors SST 2 and 5, is conserved. We have 27 cases studied during 4 years with this method, and the objective of this work is to share the results of our experience. We had cases of carcinoid small bowel tumor, ileocecal carcinoid tumor, stage IV paranglioma, Meckel type carcinoid tumor, pulmonary carcinoid tumor and septal appendectomy, carcinoid tumor of the cecum and terminal ileum, insular and trabecular carcinoid ovarian tumor and thymoma. **Methodology:** we analyzed 27 cases during January 2014 until March 2019 with Tc99m Octhreotide. The dose administered was 30 mCi, three hours after the injection, we made whole body images, SPECT the thorax and abdomen. After 20 hours we performed a second round of images with a single-headed GE Gamma Camera. Of the 27 cases studied, we ruled out 5 cases because we could not do the correct follow- up. We divided the results into 18 positives and 4 negatives for the studies of neuroendocrine tumors. We correlated our results with the biopsy, when possible (21 cases studied) and the clinical follow-up of 5 cases (especially in the negative studies for active neuroendocrine tumors). **Results and discussion:** of the 4 negative scintigraphy, 2 were negative at the close of this study. Of the 18 positive cases, 18 were confirmed by biopsy and follow-up and 1 patient died of this disease or it’ s complications. These results show 18 true positives, 2 true negatives, with a method that shows a sensitivity of 94.5% and a specificity of 100%. **Conclusion:** Tc-99m Octreotide appears to be cheaper, more available, with less radiation dose for patients, performed during a day and more easily performed (with low energy and high-resolution collimator) as an alternative to 111 In octreotide scintigraphy. With a very good sensitivity and specificity.
Technetium 99m labeled Human immunoglobulin G polyclonal antibody – different approach for better results - Aschalew Alemu Marie (Addis Ababa University, College of Health Sciences, School of Medicine, Internal Medicine Department, Nuclear Medicine Unite)
Technetium 99m labeled Human immunoglobulin G polyclonal antibody – different approach for better results
- Aschalew Alemu Marie (Addis Ababa University, College of Health Sciences, School of Medicine, Internal Medicine Department, Nuclear Medicine Unite)
23:44 - 23:59
The aim of the study was to compare the radiochemical purity of 99mTc-human immunoglobulin G using direct and indirect methods of labeling. Radiopharmaceuticals used for infection and inflammation imaging have significant use for good patient management outcomes especially in developing African countries. Several radiopharmaceuticals have been used for the diagnosis of infection and inflammation disorder. Even though none of them is ideal each one has its own strengths and weaknesses. Human immunoglobulin G as a ligand labeled with technetium-99m radionuclide provide an important characteristic since there is commercially introduced injectable form of human immunoglobulin (IgG) suitable for intravenous administration for the treatment of immunodeficiency syndrome and the availability of technetium-99m radionuclide which has the ideal radiation characteristics for diagnostic imaging from the Mo-99/Tc-99m generator. Human immunoglobulin G polyclonal antibody can be labelled with technetium using direct and indirect methods. Direct method of labeling uses a weak ligand so as to facilitate the labeling process. Sodium pyrophosphate and sodium glucoheptone the most commonly used weak ligands. Indirect labeling uses HYNIC that can serve us a bifunctional agent that can bind with both the antibody and the radionuclide. We compared the labeling efficiency including radiochemical purity of directly labeled and indirectly labeled human immunoglobulin G polyclonal antibody for infection and inflammation disorder imaging and we found out that direct labeling method provide better labeling efficiency than indirect labeling method. In addition it was realized that there is no difference in the labeling efficiency to use sodium pyrophosphate and sodium glucoheptonate as a weak ligand. Key words: Human immunoglobulin G, direct labeling, indirect labeling, infection, inflammation
The synthesis and cytotoxicity of 64Cu/NOTA-terpyridine platinum conjugate, as a novel theranostic agent - Meysam Khosravifarsani (Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada)
The synthesis and cytotoxicity of 64Cu/NOTA-terpyridine platinum conjugate, as a novel theranostic agent
- Meysam Khosravifarsani (Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada)
23:44 - 23:59
Objective: Currently, theranostics for both imaging and concomitant chemoradiotherapy is widely used in the treatment of cancerous patients. In this regard, defining the optimal timing between Pt-drugs injection and radiation delivery to the patients is an important issue. Recent advances in the field of nuclear medicine can potentially solve this problem by selective delivery of Pt-based compounds labeled with a positron/Auger-emitting radionuclide to cancer cells. In this study, we designed and validated for the first time a 64Cu-NOTA terpyridine platinum conjugate as a novel Pt-based positron/Auger emitting agent targeting G-quadruplexes DNA structure. This project is aimed to demonstrate that such theranostic agent could give rise to a synergistic effect with a greater selectivity toward cancer cells. Methodology: The in-vitro cytotoxic and synergistic effects of the conjugate were assessed by Presto-blue assay. The cellular uptake, internalization and efflux of 64Cu-NOTA terpyridine platinum conjugate was measured for colorectal cancer cell (HCT116) as well as a normal fibroblast cell line (GM05757) at 24, 48 and 72 h after initial incubation time. Results and Discussion: natCu-conjugate showed 3.4, 1.7 and 2.3 times higher cytotoxicity against HCT116 cells relative to GM05757 fibroblast normal cells. However, natCu-conjugate exhibited 9.6, 11.5, 14.1 folds lower cytotoxic effects on HCT116 cells than cisplatin at 24, 48 and 72 h, respectively. The internalization of 64Cu-conjugate in HCT116 cells increased from 15 min (0.04±0.021%) to 24h (18.7±2.8%) and followed by a plateau at 48h (18.6±1.5%), post-administration. The percentages of internalization were significantly higher in HCT116 cancer cells as compared to GM05757 normal cells at 24h, 48h and 72h post-administration (Pvalue<0.001), which is associated with higher cytotoxicity of the conjugate toward HCT116 cells. More importantly, the efflux profile of HCT116 cells showed that considerable amount of 64Cu-conjugate was retained throughout the time course from 15 min (100±7 %) to 72h (48±6%). Additionally, there was a little percentage of the conjugate (<1%) internalized at 4 °C and all time points, indicating that passive uptake of the compound is not primarily responsible for internalization. A synergistic (radiosensitizing) effect was measured for the 64Cu-conjugate (5 and 8MBq) at low concentrations (<100µM). Conversely, cell viability (%) started to increase steadily exhibiting an infra-additive (radio-protective) effect at highest concentration (500µM) on the HCT116 cells. Conclusion: These results support the potential use of 64Cu-labeled terpyridine platinum conjugate as a novel theranostic agent to diagnose and treat cancers.
Total solid-phase synthesis of DOTA-Functionalized tumor targeting peptides for PET imaging and therapy - M Okarvi Subhani (King Faisal Specialist Hospital and Research Centre. Riyadh 11211, Saudi Arabia.)
Total solid-phase synthesis of DOTA-Functionalized tumor targeting peptides for PET imaging and therapy
- M Okarvi Subhani (King Faisal Specialist Hospital and Research Centre. Riyadh 11211, Saudi Arabia.)
23:44 - 23:59
Objective: The convenient synthesis of metal chelating agents couple with tumor targeting peptides is needed to accelerate the research and clinical translation in molecular imaging. DOTA has been one of the most widely used macrocyclic ligands for the development of new metal based imaging and therapeutic agents owing to its ability to form stable and inert complexes under physiological conditions making these radiopharmaceuticals useful for imaging and therapy. DOTA-tris-t-butyl ester is commercially available, but it is expensive and contain impurities of both the di-alkylated and tetra-alkylated cyclen. There is a need to explore new methods for preparation of DOTA-tri-tert-butyl ester, which are less expensive and provides a high purity DOTA product. The aim of this study was to develop a convenient and cost effective synthetic approach for the preparation of DOTA peptides directly on solid support for tumor imaging and therapy. Methods: The tumor targeting peptide (i.e. bombesin 7-14) was synthesized by Fmoc-based solid-phase peptide synthesis. For coupling with DOTA, bromoacetic acid after activation with HOBt/DIC was coupled to free amino group of peptide resin. This was followed by the monoalkylation of bromoacetylated peptide resin with cyclen (tetraazacyclododecane). The cyclen peptide was then alkylated with tert-butylbromoacetate to afford the desired DOTA peptide. Additionally, the same peptide was prepared from commercially available tris-tert-butyl-DOTA for comparison. Theses peptides after labeling with 68Ga were evaluated for their ability to bind bombesin receptors overexpressed on human breast and prostate cancer cells. In vivo tumor targeting was examined in nude mice implanted with MDA-MB-231 xenografts. Results: The identity and purity of DOTA peptides was confirmed by mass spectrometry and HPLC. The peptides radiolabeled efficiently with 68Ga (˃90%) and exhibited high binding affinity to BN positive MDA-MB-231 and PC3 cancer cell lines (kd=<20 nM). In nude mice with MDA-MB-231 xenografts, 68Ga-labeled peptides displayed efficient clearance from the blood and uptake/retention in all the major organs was found to be low to moderate (below 5%ID/g). The accumulation in the BN positive tumors was ~2% ID/g at 1 h p.i., with good tumor to blood and muscle ratios. The main route of excretion was renal pathway. Both peptides displayed comparable in vitro and in vivo behavior. Conclusion: We have described the preparation and in vitro and in vivo activity of two DOTA coupled peptides. The synthesized peptides hold good tumor affinity and tumor targeting potential. This successful and economical synthetic strategy can be applied to the facile synthesis of various tumor targeting peptides which ultimately can be translated into clinical settings.
Use of tetrabutylammonium tosylate in conjunction with chiral NiII complex precursor for automated synthesis of [18F]FET - Olga Fedorova (N.P.Bechtereva Institute of Human Brain RAS)
Use of tetrabutylammonium tosylate in conjunction with chiral NiII complex precursor for automated synthesis of [18F]FET
- Olga Fedorova (N.P.Bechtereva Institute of Human Brain RAS)
23:44 - 23:59
Background and objectives Due to favorable characteristics in in vivo applications, high specificity and long half-life of 18F (109.8 min), the O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) has become an important tool for molecular imaging of cerebral tumors. In our previous studies we presented a convenient synthesis of [18F]FET via direct nucleophilic fluorination of a chiral NiII complex of an alkylated (S)-tyrosine Schiff base, Ni-(S)-BPB-(S)-Tyr-OCH2-CH2OTs (I) in the presence of K2.2.2 and K2CO3. After acidic hydrolysis [18F]FET was purified using reverse phase and strong cation exchange cartridges. The process was automated on the Scintomics Hotboxone synthesis module. However, when transferring this procedure to TRACERlab FX N Pro, commonly used 18F-radiolabeling platform, we observed two radiolabeled by-products that were not amendable to SPE purification procedure. Their formation may be a consequence of reaction vessel design (high volume/surface vs small amount of reaction mixture) and possible over-heating during vacuum drying of 18F-fluoride complex. As the construction of the heating block was amendable to modification, we have focused on improving fluorination process, substituting the K2.2.2/K2CO3 mixture with an alternate PTC - tetrabutylammonium tosylate (TBAOTs). The SPE purification protocol was also adjusted to better suite TRACERlab FX N Pro. Methodology Aqueous [18F]fluoride solution (1.3 ml) was loaded on Waters QMA carbonate Plus light Sep-Pak cartridge (46 mg). The cartridge was rinsed with 5 ml of MeOH and dried using gas flow; the [18F]Fluoride was eluted with 700 µl of MeOH with 4 mg of TBAOTs.. After solvent removal 4 mg of I in 700 µl of MeCN was added, and reaction mixture heated to 80oC for 7 min. After acidic hydrolysis (0.5M HCl, 110 oC, 5 min) the reaction mixture was diluted with 11 ml of water and 2.5 ml of 0.1M NaOH. Resulting basic solution (pH 9) was passed through small filtration column and three tC18 Light cartridges connected sequentially. [18F]FET was eluted with 10 ml of sodium acetate solution (5 mM, pH 4) containing 3% of EtOH and further purified by passing through CM Plus cation exchange cartridge to removal any residual nickel. Results and discussion Replacement of K2.2.2/K2CO3 with TBAOTs allowed us to substantially increase radiochemical conversion (RCC > 85%, radioTLC). Formation of radiolabeled by-products discussed earlier was not observed using gradient HPLC analysis. [18F]FET was obtained with radiochemical purity >99% and enantiomeric purity 94-95%. Decay corrected radiochemical yield was 50%, synthesis time ca. 35 min. Conslusion Using non-aqueous solution of TBAOTs as an inert PTC allowed for substantial increase of fluorination efficiency while avoiding formation of radiolabeled by-products. The radioactivity loss on the inner surfaces, which is critical for the reaction vessel on the TRACERlab FX N Pro, was minimized. The proposed synthesis methodology appears to be well-suited for transfer to other automated synthesizers for nucleophilic synthesis of 18F-labeled radiotracers. Acknowledgments: This research supported by RFBR grant 18-29-01015-mk.
Utility of Gamma Camera as an Effective Non-Invasive Imaging Modality for Docetaxel loaded Liposomal Chitosan Nanoparticles: Synthesis and the In-Vivo trafficking in Animal Model. - Ayesha Ayesha Ammar (Department of Nuclear Medicine, Nuclear Medicine oncology and Radiotherapy Institute ) Naseer Naseer Ahmed (Department of Nuclear Medicine, Nuclear Medicine, Oncology and Radiotherapy Institute )
Utility of Gamma Camera as an Effective Non-Invasive Imaging Modality for Docetaxel loaded Liposomal Chitosan Nanoparticles: Synthesis and the In-Vivo trafficking in Animal Model.
- Ayesha Ayesha Ammar (Department of Nuclear Medicine, Nuclear Medicine oncology and Radiotherapy Institute )
- Naseer Naseer Ahmed (Department of Nuclear Medicine, Nuclear Medicine, Oncology and Radiotherapy Institute )
23:44 - 23:59
Background: The physicochemical properties of drug loaded nanoparticles in physiological system are important determinants for their in vivo distribution and drug delivery efficiency. Stability of nanoparticles in blood serum remains a significant challenge for successful delivery to target tissue. Analysis of intra-biliary infusion of nanoparticles within two-compartmental pharmacokinetic modeling revealed efficient retention in the liver and minimal leakage from the liver to the blood stream. Our aim was to demonstrate the utility of Gamma camera as an effective noninvasive imaging modality for the biodistribution of docetaxel loaded liposomal chitosan nanoparticles. Methodology: Folic acid thiolated chitosan was synthesized via EDAC coupling at pH-5.0 and purified by a dialyzing membrane. NPs were partially oxidized 1h with stirring at room temperature, tween 80 was added to make an emulsion. Folic acid was grafted to TCS. The docetaxel was loaded as cross linkage using TPP (1%) solution in 500ml DCM, the weighed amount of lyophilized liposomes were suspended in 1mg/ml solution of FA-TCS and stirred for 4 hours for proper coating through electrostatic interaction between liposomes and FA-TCS. The coated liposomes were separated through ultracentrifugation. The Docetaxel loaded liposomal Thioglycolated chitosan were characterized for hydrodynamic diameter and surface zeta potential and their Surface morphology was studied with electron microscope (FEI Nova NanoSEM 450). The encapsulation efficiency was calculated by ACN: MeOH: Buffer, and quantified by HPLC-PDA. The in-vivo pharmacodynamic study was prepared docetaxel loaded liposomal thioglycolated chitosan (FORM-A) with freshly eleuted Tc-99m and docetaxel labeled alone with Tc-99m and then loaded afterwards on liposomal thioglycolated chitosan (FORM-B), by an optimized protocol to retain their favorable physicochemical properties. Radio labeling efficiency was measured by TLC-SG and methanol using BIOSCAN-TLC scanner coupled with PMT detector. The radio labeled nanoparticle complexes (avg. dose = 58±10MBq) were orally given to the animal model. Planer and static gamma images were acquired at the interval of 30 minutes, 1, 2, 3, 4, 24 and 36 hours for the localization of drug absorption and delivery site. The docetaxel drug absorption rate was quantified by HPLC. Results and Discussion: The drug loaded liposome were successfully coated with FA-TCS, confirmed by change in zeta potential. Encapsulation efficiency indicated that liposomal formulations showed higher value above 70% as compared to chitosan-TGA. The radio-labeling efficiency of both formulations measured by TLC was 99.2%. Gamma Camera acquisition quantified as activity versus time curve indicated that the FORM-A was localized in gut after 2 hours of administration and HPLC quantification confirmed that 63% of the drug was absorbed at 2 hours of administration, FORM–B images showed that the 68.2% of drug was localized in lungs, 23.2 % in liver and 8.6% was excreted through kidney, confirmation by HPLC quantification indicated slow release of drug till 36 hours. Conclusion: The use of gamma imaging can help to locate the specific site of absorption of nanoparticles and drug release while HPLC helps to quantify accurate assessment of drug release in general body circulation.
[18F]-FPSMA1007 SYNTHESIS HPLC FREE ON FASTLAB PLATFORM QC EVOLUTION - Emiliano Cazzola (Sacro Cuore Hospital) Giancarlo Gorgoni (Sacro Cuore Hospital)
[18F]-FPSMA1007 SYNTHESIS HPLC FREE ON FASTLAB PLATFORM QC EVOLUTION
- Emiliano Cazzola (Sacro Cuore Hospital)
- Giancarlo Gorgoni (Sacro Cuore Hospital)
23:44 - 23:59
**Background**: Over the past years, many different PET agents have been developed to investigating on Prostate Cancer (PC) to make the non invasive approach a reality, in order to replace the biopsy and the related complications. The PC is the more common cancer that affect the male population. Due to the high incidence of this pathology are mandatory to investigate on a fluorine-18 tracer that give the possibility to overcame the Gallium-68 tracers limitations. During the last year we have optimize a [18F]FPSMA1007 synthesis HPLC free on Ge FASTLab® module and related HPLC control. The aim of this study is to show the results of the routine productions in terms of yield and quality control by evaluation of two elution solutions (TBAHCO3/ACN or K222/ACN/K2CO3) and two HPLC methods, the reference one, based on Eclipseplus C18 and a new one based on Ascentis express Peptide Es C-18 column. **Methodology:** The synthesis method is based on one step synthesis using a new precursor commercialized by ABX and is tuned on Ge FASTLab® synthesizer. All the reagents are included on a single use cassette. The [18F]Fluorine was trapped on QMA and eluted with a mixture of TBAHCO3/ACN or K222/ACN/K2CO3 and after drying at 125°C on synthesis reactor, the ABX precursor dissolved in DMSO was added to proceed with the nucleophilic [18F]-Fluorination. The reaction mixture was heated up at 95°C for 10 min after the reaction step the mixture was cooled at 35°C to starting the purification step followed by formulation. The total process takes place on 37 minutes. HPLC analysis was performed on an Agilent 1260 Infinity HPLC equipped with an Agilent 1260 UV detector and a Raytest gamma-ray detector, controlled with OpenLAB. The analysis was performed on a 4,6x100 Eclipse Plus C18 3,5μm (Agilent) in isocratic conditions using CH3CN and 0.1 % TFA (70/30, run time 15 min) flow 0.8 ml/min and on 4,6x150 Ascentis express Peptide Es C-18 2,7um flow 1.3 ml/min in gradient methods using CH3CN and a solution of dihydrogen phosphate and phosphoric acid. **Results:** Two different elution solution was used to compare the final process yields, at the same time, high activity runs were performed, in different inlet activity range, to evaluating the yield and product stability in final formulation. For stability study a range of 1-2.5 GBq/ml radioactive concentration was evaluated at room and at 40°C for up to 12h. According to final product formula specification the synthesis yield was stable on range 35-55 % at the inlet activity range (55-185 GBq) with a very high Am (800-3500 GBq/µmol) at EOS. The radiochemical purity for all the runs were always higher than 95%. The chemical HPLC profile shows differences in separation for the FPSMA1007, OHPSMA1007 HPSMA1007 and reaction precursor that make difference in chemical purity evaluation. All the synthesis performed by using the K222 elution solution shows slightly lower yield compared to TBA, at the same time only the HPLC methods based on Ascentics column allow to have a right chemical purity evaluation due to the more efficient peak resolution.
[89Zr]ZrOx/Cl preparation based on commercial cassette base, synthesis module. - Emiliano Cazzola (Sacro Cuore Hospital)
[89Zr]ZrOx/Cl preparation based on commercial cassette base, synthesis module.
- Emiliano Cazzola (Sacro Cuore Hospital)
23:44 - 23:59
**Background:** [89Zr]Zirconium is one of the emergent isotope due to the favorable PET imaging characteristics (β+max 0.395 MeV; 22.7%) and halflife (T½78.4h) ideal to labeling Antibodies. Monoclonal antibodies (MAbs) are the most approved biopharmaceutical in the word with a multiple and selective targets.The immunoPET can facilitate the approval for new MAbs and can help on patient selection. Due of this needs a robust production, purification and labelling procedure should be optimized on automatic modules in order to minimize the operator dosimetry and increase the reproducibility. Aim of this work is based on easy modification of automatic, cassette base, commercial module in order to dissolve and purify the [89Zr]Zirconium in both formulation currently used from sputtered target. The single use cassette reducing the possibility to accumulate metal impurities in the purification step due to missing cleaning step mandatory on synthesis modules based on fixed tubes technology . **Methodology:** A Eckert&Ziegler cassette base module were used to set up an automatic dissolution and purification procedure. The Sputtered [89Y]Yttrium targets were bombarded on TR-19 cyclotron at 12.5 MeV without degrader at different current 20-60 µA for a variable time 30-240 minutes. The coins were transferred on dedicated coated hotcell and finally insert on a EZAG module in order to dissolve and purify the [89Zr]/[89Y] material in a single use cassette. A 2 N HCl solution was used to dissolve the target material, the solution was transfer to ZR resin (Triskem) and recovered on vial in oxalate or chloride form . Ten sputtered target were processed after bombardment and final impurities profile were evaluated by γ-spettrometry and by ICP-MS . **Conclusion:** What we described on this work is one of the possible way to optimize the [89Zr]Zirconium production starting from [89Y]Yttrium sputtered target, with a simple and single use cassette recovery process based on EZAG module to minimize the impurities.
Wednesday, 30 October 2019
09:00
09:00 - 10:30
Contributions

09:00 D. Paez: IAEA activities related to Nuclear Medicine

09:30 H. Macapinlac: Recent Advances in Nuclear Medicine: diagnostic and therapy

10:00 D. Le: Production and Use of Cyclotron-produced Radiopharmaceuticals at MD Anderson Cancer Center
Production of radiopharmaceuticals: Theranostic
Production of radiopharmaceuticals: Theranostic
09:00 - 10:30
Room: M1
Contributions

09:00 P. Elsinga: Recent advances in the development of 18F and 11C radiopharmaceuticals (IS)

09:25 C. Decristoforo: Recent advances in the development of 68Ga radiopharmaceuticals (IS)

09:45 SYNTHESIS AND IN VITRO AND IN VIVO EVALUATION OF IODINE-124-LABELED PSMA PEPTIDES: POTENTIAL THERANOSTIC RADIOPHARMACEUTICALS FOR PROSTATE CANCER - IBRAHIM ALJAMMAZ ( KING FAISAL SPECIALIST HOSPITAL & RESEARCH CENTRE )

10:00 V. Kumar: A radiocopper somatostatin anolog (Cu-Sartate) for NET theranostics (IS)

10:15 Comparative study of [18F]PSMA-1007and [68Ga]PSMA-11 for Prostate Cancer PET Imaging in Thailand - Wisakha Chintawan (National Cyclotron and PET Centre, Chulabhorn Hospital, Chulabhorn Royal Academy)
10:30 Coffee Break
Coffee Break
10:30 - 11:00
Room: Foyer

11:00 QA/QC/Pre-clinical
QA/QC/Pre-clinical
11:00 - 12:30
Room: M1

12:30 Lunch Break
Lunch Break
12:30 - 14:00

14:00 Health regulations: production of radiopharmaceuticals
Health regulations: production of radiopharmaceuticals
14:00 - 15:30
Room: M1

15:30 Coffee Break
Coffee Break
15:30 - 16:00
Room: Foyer

16:00 Health regulations: production of radiopharmaceuticals
Health regulations: production of radiopharmaceuticals
16:00 - 17:30
Room: M1

18:00

18:00 - 19:00
Thursday, 31 October 2019

09:00 Production of alpha emitters and radiopharmaceuticals
Production of alpha emitters and radiopharmaceuticals
09:00 - 10:30
Room: M1
09:00 - 10:30
Contributions

09:00 IAAEA TC Speakers

09:30 R. Montaña: Sustainable production of 99mTc generators and radiopharmaceuticals an IAEA/Cuban experience (IS)

09:55 Yelena Chakrova Kazhakstan

10:15 A. Duran: Strengthening capacities for the development of radiotracers labelled with 18F, different from fluordesoxyglucose in the FCDN (N.6)
10:30 Coffee Break
Coffee Break
10:30 - 11:00
Room: Foyer

11:00 Emerging radioisotopes for radiopharmacy
Emerging radioisotopes for radiopharmacy
11:00 - 12:30

12:30 Lunch Break
Lunch Break
12:30 - 14:00

14:00

14:00 - 15:30
Room: M1

15:30 Coffee Break
Coffee Break
15:30 - 16:00
Room: M1

16:00 Radiopharmacy installations
Radiopharmacy installations
16:00 - 17:30
Room: M1

18:00 S.14 IAEA Databases and Apps (17:30-18:30)
S.14 IAEA Databases and Apps (17:30-18:30)
18:00 - 19:00
Room: M1
Friday, 1 November 2019

09:00 Education in Radiopharmacy
Education in Radiopharmacy
09:00 - 10:30
Room: M1

10:30 Coffee Break
Coffee Break
10:30 - 11:00
Room: M1

11:00 Finalists
Finalists
11:00 - 12:30
Room: M1

12:30 Lunch Break
Lunch Break
12:30 - 14:00

14:00

14:00 - 15:30
Room: M1