Fully automated synthesis of [¹⁸F]fluorocholine on GE FASTlab II synthesizer

A reliable and fully automated method for synthesis, purification and formulation of [¹⁸F]FCH on the GE FASTlab II utilizing a single-use cassette was reported. The radiosynthesis sequences of [¹⁸F]FCH was written based on the two-step, gas phase synthesis methodology. Dibromomethane (DBM) was fluorinated with no-carrier-added [¹⁸F]fluoride ion, assisted by K₂₂₂/K₂CO_3, to afford [¹⁸F]fluorobromomethane ([¹⁸F]FBM) as a gas. [¹⁸F]FCH was then prepared by bubbling [¹⁸F]FBM through Sep-Pak Silica cartridges to react with dimethylethanolamine (DMAE) preloaded on Sep-Pak C18 cartridge. The resulting [¹⁸F]FCH was purified using Sep-Pak C18 and Accell CM cartridges in series. The purified [¹⁸F]FCH was eluted from the CM cartridge and formulated with 0.9 % sodium chloride for injection. With this method, the radiochemical yield of [¹⁸F]FCH was 17.8 ± 2.5 % with a high radiochemical purity (>99 %). Three consecutive [¹⁸F]FCH validation runs were performed, and all quality control parameters met the release criteria for human use. This method is quite straightforward utilizing single-use cassettes. [¹⁸F]FCH was reproducibly produced at sufficiently high radioactive concentration for multiple preclinical or human imaging doses from a single radiosynthesis.