Radiosynthesis and evaluation of IGF1R PET ligand [11C]GSK1838705A

Abstract Radiosynthesis and evaluation of [ 11 C]GSK1838705A in mice using microPET and determination of specificity in human GBM UG87MR cells are described herein. The radioligand was synthesized by reacting desmethyl-GSK1838705A with [ 11 C]CH 3 I using GE FX2MeI module in ∼5% yield (EOS), >95% radiochemical purity and a specific activity of 2.5 ± 0.5 Ci/μmol. MicroPET imaging in mice indicated that [ 11 C]GSK1838705A penetrated blood brain barrier (BBB) and showed retention of radiotracer in brain. The radioligand exhibited high uptake in U87MG cells with >70% specific binding to IGF1R. Our experiments suggest that [ 11 C]GSK-1838705A can be a potential PET radiotracer for the in vivo quantification of IGF1R expression in GBM and other brain tumors.