Simplified quantification and whole-body distribution of [18F]FE-PE2I in nonhuman primates: prediction for human studies

Introduction[18F]FE-PE2I is a promising dopamine transporter (DAT) radioligand. In nonhuman primates, we examined the accuracy of simplified quantification methods and the estimates of radiation dose of [18F]FE-PE2I.MethodsIn the quantification study, binding potential (BPND) values previously reported in three rhesus monkeys using kinetic and graphical analyses of [18F]FE-PE2I were used for comparison. BPND using the cerebellum as reference region was obtained with four reference tissue methods applied to the [18F]FE-PE2I data that were compared with the kinetic and graphical analyses. In the whole-body study, estimates of adsorbed radiation were obtained in two cynomolgus monkeys.ResultsAll reference tissue methods provided BPND values within 5% of the values obtained with the kinetic and graphical analyses. The shortest imaging time for stable BPND estimation was 54 min. The average effective dose of [18F]FE-PE2I was 0.021 mSv/MBq, similar to 2-deoxy-2-[18F]fluoro-d-glucose.ConclusionsThe results in nonhuman primates suggest that [18F]FE-PE2I is suitable for accurate and stable DAT quantification, and its radiation dose estimates would allow for a maximal administered radioactivity of 476 MBq in human subjects.