Atanasova, Marija and Cocevska, Maja and Kolevska, Katerina and Velickovska, Maja and Jolevski, Filip and Janevik-Ivanovska, Emilija (2018) Optimization of production of [11C]CH3I with Methylator II for synthesis and development of [11C]radiopharmaceuticals. In: 19th European Symposium on Radiopharmacy and Radiopharmaceuticals (ESRR’18), 05-08 April 2018, Groningen, Netherlands.
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Abstract
Aim: University Institute of Positron Emission Tomography Skopje is equipped with the Methylator II (Comecer Spa. Former Veenstra In- struments BV.), a module designed for the production of high spe- cific activity MethylIodide ([11C]CH3I) and/or Methyl Triflate ([11C]CH3OSO2CF3) and CarbonSynthon I (Comecer Spa.) for produc- tion of simple 11C radiopharmaceuticals. The synthesis process starts with the production of [11C]CO2 in the cyclotron (GE PETtrace 16.5MeV) via the 14N(p,α)11C nuclear reaction. The produced [11C]CO2 is delivered into the Methylator, where it first was trapped and sub- sequently reduced to [11C]CH4 and converted thereafter into [11C]CH3I and/or [11C]CH3OSO2CF3. The trapped [11C]CO2 in the Methanizer was reduced into a [11C]CH4 with hydrogen on a nickel catalyst (Shinwasorb) at a rather moderate temperature 350 0C. The next step was the purification of the [11C]CH4 over a Carboxen 1000 column, with the knowledge that the H2 will flow about 7 times fas- ter than [11C]CH4 through carbon packing causing the separation of H2 and CH4. This is one of the most important steps in the produc- tion process which affects directly the equilibrium reaction which forms the [11C]CH3I and HI, which is formed in the iodine oven by the reaction of H2 and I2 as well
Methods: Optimization experiments where performed maximizing the yield of [11C]CH3I. By changing the time for switching the valve V04 (see diagram) the effectiveness of the purification was influ- enced. In ‘Active’ state the formed [11C]CH4 and excess of H2 was di- rected toward waste, but in ‘Inactive’ state in direction of the Iodine Oven. If the time was too short the reduced [11C]CH4 would not be separated thorougly enough from the H2, but when the time was too long the produced [11C]CH4 would be lost into waste. The first syntheses were performed with V04 active for 25 sec upon release of the [11C]CH4, after which it was deactivated. Different timings for switching the valve were tested and the different yields were obtained.
Results Our result presented in the Table showed that yield of [11C] CH3I and [11C] Choline is purification time depended. By increasing the time of purification (from 20 to 37 seconds) obtained trapped [11C] CO2, is more than four time higher and harvested [11C] CH3I as well. After 37 seconds we obtained 41% of [11C] CH3I that is directly reflected to the yield of [11C] Choline (34.6), fitting with our protocol for synthesis of [11C] Choline.
Conclusion: The module and software give us a big opportunity and flexibility for testing and optimization of the production achieving a better yield, and also the development of new 11C radiopharmaceuticals.
| Item Type: | Conference or Workshop Item (Poster) |
|---|---|
| Subjects: | Medical and Health Sciences > Health biotechnology Medical and Health Sciences > Other medical sciences |
| Divisions: | Faculty of Medical Science |
| Depositing User: | Emilija Janevik |
| Date Deposited: | 06 Feb 2019 08:12 |
| Last Modified: | 06 Feb 2019 08:12 |
| URI: | https://eprints.ugd.edu.mk/id/eprint/21518 |
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