Fully automated one-pot radiosynthesis of O-(2-[18F]fluoroethyl)-L-tyrosine on the TracerLab FX(FN) module.

INTRODUCTION: An efficient fully automated method for the radiosynthesis of enantiomerically pure O-(2-[(18)F]fluoroethyl)-L-tyrosine ([(18)F]FET) using the GE TracerLab FX(FN) synthesis module via the O-(2-tosyloxyethyl)-N-trityl-L-tyrosine tert-butylester precursor has been developed.

METHODS: The radiolabelling of [(18)F]FET involved a classical [(18)F]fluoride nucleophilic substitution performed in acetonitrile using potassium carbonate and Kryptofix 222, followed by acid hydrolysis using 2N hydrochloric acid.

RESULTS: [(18)F]FET was produced in 35±5% (n=22) yield non-decay-corrected (55±5% decay-corrected) and with radiochemical and enantiomeric purity of >99% with a specific activity of >90 GBq/μmol after 63 min of radiosynthesis including HPLC purification and formulation.

CONCLUSION: The automated radiosynthesis provides high and reproducible yields suitable for routine clinical use.