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

A method and an apparatus for preparing [ 11 C]methyl iodide from [ 11 C]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 [ 11 C]methane used in the experiments was produced from [ 11 C]carbon dioxide via reduction with hydrogen over nickel. [ 11 C]methyl iodide was obtained with a specific radioactivity of 412 ± 32 GBq/ µ mol within 6 min from approximately 24 GBq of [ 11 C]carbon dioxide. The decay corrected radiochemical yield was 13 ± 3% based on [ 11 C]carbon dioxide at start of synthesis. [ 11 C]Flumazenil was synthesized via a N ‐alkylation with the prepared [ 11 C]methyl iodide. Copyright © 2006 John Wiley & Sons, Ltd.