Purpose: Cancer risk models stemming from atomic bomb survivor data still rely on the results of the DS86 and DS02 dosimetry systems published by the Radiation Effects Research Foundation (RERF). This study investigates the dosimetry impact on the pregnant female (PF) population of atomic bomb survivors by utilizing a newly created series of kneeling and lying pregnant female computational phantoms.
Methods: Utilizing the original standing series of J45 PF phantoms, a new series of both kneeling and lying J45 PF phantoms has been constructed to include gestational ages of 8, 15, 25, and 38 weeks. Kneeling phantoms were constructed using scripting methods within the 3D modeling program Rhinoceros®. Lying phantoms were created by rotating the original standing J45 series of PF phantoms in 3D space. Organ doses for both posture phantoms were computed via Monte Carlo transport code PHITS using particle fluences provided by DS02 for both Hiroshima and Nagasaki exposures. Maternal and fetal organ doses from the J45 PF phantoms were compared to the corresponding maternal organ and uterine wall, respectively, in the non-pregnant stylized adult female phantom used in DS02.
Results: For kneeling phantoms, organ doses from photon spectra were overestimated compared to DS02 by as much as 40% for certain fetal and maternal organs. For lying phantoms, fetal organ doses from photon spectra were underestimated up to 25% while maternal organ doses were overestimated up to 15% related to DS02 organ doses. Neutron contributions to organ doses exhibited from neutron contributions exhibit an increasing overestimation in DS02 as gestational age increases.
Conclusion: This work highlights the degree to which fetal and maternal dosimetry varies from the DS02 report with the introduction of newly created computational phantoms for both the kneeling and lying survivor cohort of pregnant women.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by: Radiation Effects Research Foundation, National Institutes of Health, Japan Atomic Energy Agency
Not Applicable / None Entered.