Automated and efficient radiosynthesis of [18F]FLT using a low amount of precursor

Abstract Introduction Since 1991 until now, many radiosyntheses of [ 18 F]FLT have been published. Most of them suffer from side reactions and/or difficult purification related to the large amount of precursor necessary for the labeling step. A fully automated synthesis using only commercial and unmodified materials with a reduced amount of precursor would be desirable. Methods We first explored the possibility to elute efficiently [ 18 F]fluorine from commercial and unmodified cartridges with various amount of base. Based on these results, 10 mg and 5 mg of precursors were used for the fluorination step. The best conditions were transposed in an automated process for a one pot two steps synthesis of labeled FLT. Results Using commercial and non-treated carbonate form of QMA cartridges, we were able to elute quantitatively the [ 18 F]fluorine with a very low amount of base (0.59 mg) and, with only 5 mg of precursor, to perform an efficient fluorination reaction with up to 94% incorporation of [ 18 F]fluorine. The synthesis was fully automated and radiochemical yields of 54% (decay corrected) were obtained within a synthesis time of 52 minutes. Conclusion We demonstrate that a fully automated and efficient radiosynthesis of [ 18 F]FLT is feasible with only 5 mg of precursor. Compare to the present state of the art, our method provides high yields of pure [ 18 F]FLT and is broadly adaptable to other synthesis automates.