[11C]methyl iodide from [11C]methane and iodine using a non-thermal plasma method

A method and an apparatus for preparing [C-11]methyl iodide from [C-11]methane and iodine in a single pass through a non-thermal plasma reactor has been developed. The plasma was created by applying high voltage (400 V/31 kHz) to electrodes in a stream of helium gas at reduced pressure. The [C-11]methane used in the experiments was produced from [C-11]carbon dioxide via reduction with hydrogen over nickel. [C-11]methyl iodide was obtained with a specific radioactivity of 412 +/- 32 GBq/mu mol within 6 min from approximately 24 GBq of [C-11]carbon dioxide. The decay corrected radiochemical yield was 13 +/- 3% based on [C-11]carbon dioxide at start of synthesis. [C-11]Flumazenil was synthesized via a N-alkylation with the prepared [C-11]methyl iodide. Copyright (c) 2006 John Wiley & Sons, Ltd.