RADAR Develops New Generation of Radiation Dosimetry Phantoms and Radiopharmaceutical Dose Estimates

Objectives: In 2003, the RADAR (RAdiation Dose Assessment Resource) method for internal dose estimation was established and was implemented in the personal computer software code OLINDA/EXM 1.0. RADAR also developed a new generation of realistic, image-based, voxel anthropomorphic phantoms, based on the organ masses in ICRP Publication 89 (2003), to represent adults, children of various ages, and pregnant women at different stages of gestation. This technology was employed to generate a large compendium of dose estimates for different radiopharmaceuticals commonly employed in nuclear medicine.

Methods: Biokinetic models for nearly 100 radiopharmaceuticals were used with the OLINDA/EXM 2.0 adult and pediatric phantoms to develop dose estimate tables. Most of the biokinetic models were taken from those proposed by the ICRP Task Group on Radiopharmaceutical Dosimetry (2015). Dose estimates for the embryo/fetus were also generated for about 50 radiopharmaceuticals employed in women of childbearing age. RESULTS: The dose estimates were listed in tables - for adult males and females , and male and female children of ages 15 years, 10 years, 5 years, and 1 year (all with gender averaged values provided as well), and fetal doses for women in early pregnancy and at 3-, 6-, and 9-months’ gestation. The tables are distributed online via the RADAR web site, but, unlike other published compendia, are subject to constant change, as existing radiopharmaceutical models are changed, or as new radiopharmaceuticals are added. Limited results (e.g. for the highest dose organ and effective dose for a given diagnostic radiopharmaceutical, and fetal dose estimates) are available through an SNMMI interactive web tool and smart phone apps. CONCLUSIONS: The phantoms and dose estimates based on the 1980-1990 generation of ‘stylized’ phantoms have been updated and replaced by a new generation of models, based on updated organ mass information and realistic, voxel-based anthropomorphic phantoms. These data will serve the nuclear medicine user community for many years to come; the use of electronic, instead of paper, technology allows constant updating of the results.