Easy upgrade of the TRACERLab FX C Pro for [11C]carboxylation reactions: Application to the routine production of [1-11C]acetate

Carbon-11-labeled acetate ([1-11C]acetate) is a radiopharmaceutical of importance in clinical practice as well as in preclinical research in cardiology and oncology. Its preparation is based on the [11C]carboxylation reaction of a Grignard reagent with [11C]CO2. Most of the commercially available synthesizers are only dedicated to the preparation of [11C]methyl iodide (or [11C]methyl triflate) for the radiomethylation of an appropriate precursor but not for the direct use of cyclotron-produced [11C]CO2. Based on the classical [11C]carboxylation reaction and SPE purification, we propose in this technical note a detailed, simple, easy-to-handle and fully reversible modification of the TRACERLab FX C Pro to operate, on demand, [11C]carboxylation reactions, exemplified herein by the production of [1-11C]acetate, or [11C]radiomethylation reactions. This also opens new prospects to other type of radiochemical reactions involving [11C]CO2.