Optimizing Conditions of ¹¹C-CH₃I Production in Single Vessel, Synthesis and Clinical Application of ¹¹C-choline

The reaction conditions, including the amount of raw material, reaction temperature, evaporation time, pressure and flow rate of carrier gas for ¹¹C-CH₃I were investigated. The corrected yield of ¹¹CH₃I under optimized conditions (0.3 mL LiAlH₄, 0.5 mL 57% HI，0.28 kPa gas pressure, 27 mL/min carrier gas flow rate, 180 ℃ reaction temperature and 12 min evaporation time) was 62.2%±3.4% and the radiochemical purity was more than 95%. ¹¹C-choline PET/CT imaging in 2 patients was studied and compared with ¹⁸F-FDG PET/CT imaging. High uptake with ¹¹C-choline and low uptake with ¹⁸F-FDG in tumor were observed.