Development of an automated system for the routine preparation of carbon-11 labeled radiopharmaceuticals

An automated system was developed for the routine preparation of carbon-ii (C-11) labeled radiopharmaceuticals, which consisted of three major parts including [C-11]methylation of the precursor with [C-11] iodomethane ([C-11]CH3I), purification of the desired product and formulation of the final C-11 labeled radiopharmaceutical. The whole system included seven three-way slider valves, eleven solenoid valves, four pneumatic cylinders, a HPLC (High Performance Liquid Chromatography) system and a rotary evaporator. Using this system, we investigated the radiochemical synthesis of L-[methyl-C-11]methionine, which is the most widely used amino acid in tumor PET (Positron Emission Tomography) studies. The overall operation took 30-35 min including the production of [C-11]CH3I (10.5 min) and decay-corrected radiochemical yield was 25%. The automated system we described herein can be widely utilized for the preparation of many C-11 labeled radiopharmaceuticals and has been shown to be efficient, reliable and easy to operate.