PHYSIOLOGICALLY-BASED PHARMACOKINETICS MODEL FOR ESTIMATING URINARY-EXCRETION OF SHORT HALF-LIFE NUCLIDES IN NUCLEAR-MEDICINE

The biokinetic model in ICRP 53 is used for calculating absorbed dose to each organ of a patient in nuclear medicine. The ICRP model is a si mple compartment model based on human data; however, the model cannot produce the biokinetics of radiopharmaceuticals under various physiolo gical conditions. On the other hand, a physiologically based pharmacok inetics model (PBPK model) can describe the flow of radiopharmaceutica ls as a compartment model for any physiological conditions theoretical ly. The PBPK model was applied especially for the kidney-bladder dynam ics, and similar results obtained compared with the ICRP model. This s uggests the possibility of the PBPK model for predicting the biokineti cs of radiopharmaceuticals under various physiological conditions.