LAUSR

PURPOSE The combination of nonhuman primates (NHPs) with state-of-the-art molecular imaging technologies allows for within-subject longitudinal research aiming at gaining new insights into human normal and disease conditions and provides an ideal foundation for future translational studies of new diagnostic tools, medical interventions and therapies. However, radiation dose estimations for nonhuman primates from molecular imaging probes are lacking and are difficult to perform experimentally. The aim of this work is to construct age-dependent NHP computational model series to estimate the absorbed dose to NHP specimens in common molecular imaging procedures. MATERIALS AND METHODS A series of NHP models from baby to adult were constructed based on non-uniform rational B-spline surface (NURBS) representations. Particle transport was simulated using Monte Carlo calculations to estimate S-values from nine positron-emitting radionuclides and absorbed doses from PET radiotracers. RESULTS Realistic age-dependent NHP computational model series were developed. For most source-target pairs in computational NHP models, differences between C-11 S-values were between -13.4% and -8.8%/Kg difference in body weight while differences between F-18 S-values were between -12.9% and -8.0%/Kg difference in body weight. The absorbed doses of 11 C-labelled brain receptor substances, 18 F-labelled brain receptor substances and 18 F-FDG in the brain ranged within 0.047 - 0.32 mGy/MBq, 0.25 - 1.63 mGy/MBq and 0.32 - 2.12 mGy/MBq, respectively. CONCLUSION The absorbed doses to organs are significantly higher in the baby NHP model than in the adult model. These results can be used in translational longitudinal studies to estimate the cumulated absorbed organ doses in NHPs at various ages.