Fully automated synthesis of O-(2′-[18F]fluoroethyl)-l-tyrosine ([18F]FET) using solid phase extraction (SPE) purification with neutral alumina

[18F]FET was synthesized using O-(2′-tosyloxyethyl)-N-trityl-l-tyrosine-tert-butyl ester (TET) precursor. SPE purification of [18F]FET, after radio-synthesis, using neutral alumina column was satisfactory, with radiochemical and enantiomeric purity of >99 %. Decay-uncorrected synthesis yield with 8 mg TET was 19.07 ± 1.3 and 8.76 ± 0.46 % when eluted in 35 and 17 mL of buffered saline, respectively, for practical considerations. O-(2′-hydroxyethyl)-l-tyrosine formed during synthesis could be reduced nine-fold to <2 µg/mL by using 2 mg TET but with ~30 % less yield. Bio-distribution and Micro-PET imaging in C57BL/6 mice with B16F10-induced-melanoma showed tumor/brain ratio of 2.8 at 60 min. With SPE, [18F]FET production is simplified like 2-[18F]FDG.