Improvement of internal dose calculations using mathematical models of different adult heights

In internal dosimetry for both nuclear medicine and radiation protection, the adult morphology is represented by a limited number of anthropomorphic models that may not be suitable for all patients. To develop more patient-specific dosimetry, we derived six mathematical models for adults of different height. Three male models (160 cm, 170 cm and 180 cm) and three female models (150 cm, 160 cm and 170 cm), based on the MIRD model design, were developed from the statistical analysis of anthropometric data gathered from autopsies. Monte Carlo calculations were used to provide an example of estimations of S value for these new models for iodine 131 uniformly distributed successively in the stomach or in the urinary bladder. On average, for both male and female models, an increase in the model height of 10 cm leads to a mean reduction in the S value for iodine-131 by 20% and 29% when the stomach and the urinary bladder respectively are selected as source regions. Similarly, when the model height increases by 20 cm, the S values decrease on average by 35% and 48%. This study presents the use of anthropometric data to develop new mathematical models for adults of different height, and shows the significant influence of the morphology on dosimetric parameters.