[1-(11)C]palmitic acid: improved radiopharmaceutical preparation.

A simple synthetic procedure and processing system for the routine preparation of [1-(11)C]palmitic acid via carbonation of n-pentadecylmagnesium bromide with [11C]carbon dioxide is described. The key feature of this improved synthesis is the facile separation of the 11C fatty acid from the radiolabeled and unlabeled by-products of the Grignard reaction. Using this procedure and system 7.40-9.25 GBq (200-250 mCi) of [11C]CO2 was converted, after a synthesis time of 30 min, into 1.85-2.78 GBq (50-75 mCi) of pure, sterile, pyrogen-free [1-(11)C]palmitic acid suitable for human use with positron computed tomography.