Electrophilic synthesis of 6-[18F]fluoro-L-DOPA using post-target produced [18F]F2

Abstract

Abstract New diagnostic uses of 6-[ 18F]fluoro-L-DOPA ([ 18F]FDOPA) for endocrine cancers and for focal hyperinsulism of infancy have renewed interest in simple and reproducible methods to synthesize it in high quantity. Fluorodestannylation is a simple and regioselective means to produce [ 18F]FDOPA. We have successfully used post-target produced [ 18F]F2 as a labeling agent in fluorodestannylation. We are able to produce in one synthesis enough [ 18F]FDOPA for several human PET studies at Turku PET Centre. The average radiochemical yield in 50 syntheses was 6.4±1.7% (calculated from [ 18F]F−), with radiochemical purity >98% and mean specific radioactivity at the end of synthesis 3.7±0.9 GBq/μmol. With this method the amounts of the reagents used in the synthesis are considerably reduced in comparison to other electrophilic labeling approaches. Thus the manipulations during the synthesis and the purification of the product are simplified.