Successive preparation of 11C labeled sodium acetate and/or sodium hexanoate

A system for two-lot delivery of [1-11C]acetate and/or [1-11C]hexanoate using an automated synthesis unit for 11C-methylation with [11C]methyl iodide is described. Carboxylation of methylmagnesium bromide and pentylmagnesium bromide with [11C]CO2 followed by HCl hydrolysis gave [1-11C]acetic acid and [1-11C]hexanoic acid, respectively. The reaction mixture was passed through a Sep-IC-Ag cartridge, and the eluate was added to a NaHCO3 solution. After removing radioactive and non-radioactive undesirable materials by evaporation of the solution to dryness, the residue was dissolved in physiological saline. By membrane filtration, a sterile and apyrogenic solution of [1-11C]acetic acid or medium-chain fatty acids such as [1-11C]hexanoic acid was ready for injection within 15 min of EOB. The reaction was successively carried out using two reaction sites in the system.