Fully automated one-pot radiosynthesis of O-(2-[18F]fluoroethyl)-l-tyrosine on the TracerLab FXFN module

IntroductionAn efficient fully automated method for the radiosynthesis of enantiomerically pure O-(2-[18F]fluoroethyl)-l-tyrosine ([18F]FET) using the GE TracerLab FXFN synthesis module via the O-(2-tosyloxyethyl)-N-trityl-l-tyrosine tert-butylester precursor has been developed.MethodsThe radiolabelling of [18F]FET involved a classical [18F]fluoride nucleophilic substitution performed in acetonitrile using potassium carbonate and Kryptofix 222, followed by acid hydrolysis using 2N hydrochloric acid.Results[18F]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.ConclusionThe automated radiosynthesis provides high and reproducible yields suitable for routine clinical use.