Automated Synthesis of [N-Methyl-¹¹C]choline, Radiopharmaceutical for Tumor Imaging by PET

An automated method has been developed for the synthesis of [N-methyl-¹¹C]choline, a radiopharmaceutical (RP) for the diagnosis of cancer using positron emission tomography (PET). The synthesis was carried out on a home-made module, using combined technology of on-line ¹¹C-methylation processes and solid-phase extraction methods. The radiochemical yield of [N-methyl-¹¹C]choline was 80% (based on the activity of the methylating agent, [¹¹C]CH₃I, decay corrected), which ensures the production of several clinical doses of radiopharmaceutical in one batch. [N-Methyl-¹¹C]choline was obtained with a radiochemical purity of more than 99% and an amount of 2-dimethylaminoethanol (the main chemical impurity) of 0.06 mg/mL, which meets the requirements of the Russian and European Pharmacopoeia.