Dosimetric Impact of a New Computational Voxel Phantom Series for the Japanese Atomic Bomb Survivors: Methodological Improvements and Organ Dose Response Functions

Sato, Tatsuhiko; Funamoto, Sachiyo; Paulbeck, Colin; Griffin, Keith; Lee, Choonsik; Cullings, Harry M.; Egbert, Stephen D.; Endo, Akira; Hertel, Nolan E.; Bolch, Wesley E.

doi:10.1667/rr15546.1

Cited by 6 publications

(9 citation statements)

References 18 publications

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“…Modern MC codes can efficiently handle the electron transport within the body. In previous work by Sato et al, development of an air-generated electron database was undertaken, providing a phase space of electrons generated outside of the body for the DS02 gamma fluences considered in the present work (Sato et al 2020 ). The electrons arising from particle fluence interactions with 20 m of air were recorded onto the coupling surface surrounding the phantom; the distance of 20 m corresponds to the approximate range of a 4.5 MeV electron in air, which is expected to capture the majority of air electrons generated within the survivor’s local environment.…”

Section: Electron Transport and Air-generated Electron Phase Space Da...mentioning

confidence: 99%

“…The phase space source terms created through this work, as well as the air-generated electron database created by Sato et al ( 2020 ), were used to calculate organ absorbed doses within the J45 phantom series for 28 organs and tissues: the adrenal glands, brain, breasts, colon, esophagus, extrathoracic region, eye lens, gall bladder wall, heart wall, kidneys, liver, lungs, lymph nodes, muscle, oral mucosa, ovaries, pancreas, prostate, salivary glands, small intestine wall, skin, spleen, stomach wall, testes, thymus, thyroid, urinary bladder wall, and uterus. For simulations of the neutron spectra, the F6 tally (MeV/g) was used to record neutron organ dose deposition.…”

Section: Fluence Source Termsmentioning

confidence: 99%

“…Thus, one may potentially utilize such a library of response functions to build survivor doses based on the available particle fluences at each survivor’s specific environment. More information on this process can be found in Sato et al ( 2020 ).…”

Section: Study Limitationsmentioning

confidence: 99%

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Japanese pediatric and adult atomic bomb survivor dosimetry: potential improvements using the J45 phantom series and modern Monte Carlo transport

Griffin

Sato

Funamoto

et al. 2021

Radiat Environ Biophys

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The radiation exposure estimates for the atomic bomb survivors at Hiroshima and Nagasaki have evolved over the past several decades, reflecting a constant strive by the Radiation Effects Research Foundation (RERF) to provide thorough dosimetry to their cohort. Recently, a working group has introduced a new series of anatomical models, called the J45 phantom series, which improves upon those currently used at RERF through greater age resolution, sex distinction, anatomical realism, and organ dose availability. To evaluate the potential dosimetry improvements that would arise from their use in an RERF Dosimetry System, organ doses in the J45 series are evaluated here using environmental fluence data for 20 generalized survivor scenarios pulled directly from the current dosimetry system. The energy- and angle-dependent gamma and neutron fluences were converted to a source term for use in MCNP6, a modern Monte Carlo radiation transport code. Overall, the updated phantom series would be expected to provide dose improvements to several important organs, including the active marrow, colon, and stomach wall (up to 20, 20, and 15% impact on total dose, respectively). The impacts were especially significant for neutron dose estimates (up to a two-fold difference) and within organs which were unavailable in the previous phantom series. These impacts were consistent across the 20 scenarios and are potentially even greater when biological effectiveness of the neutron dose component is considered. The entirety of the dosimetry results for all organs are available as supplementary data, providing confident justification for potential future DS workflows utilizing the J45 phantom series.

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Section: Electron Transport and Air-generated Electron Phase Space Da...mentioning

confidence: 99%

Section: Fluence Source Termsmentioning

confidence: 99%

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Japanese pediatric and adult atomic bomb survivor dosimetry: potential improvements using the J45 phantom series and modern Monte Carlo transport

Griffin

Sato

Funamoto

et al. 2021

Radiat Environ Biophys

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“…Additionally, the J45 series was expanded to include four pregnant female (PF) phantoms at 8 wk, 15 wk, 25 wk, and 38 wk post-conception (Paulbeck et al 2019). In the third publication from the Working Group, we proposed the development of fluence-to-organ dose response functions (varying by particle type, energy, and direction to the J45 phantoms) as a computationally efficient means of updating the Organ Dose Module of the DS02 system (Sato et al 2020). In a recent study by Griffin et al (2022), realistic DS02 exposure scenarios—including in-the-open exposures and exposure within and adjacent to both lightly and heavily shielded houses—were used to assess the magnitude of organ dose changes potentially realized with a change from the DS86 stylized phantoms to the more anatomically realistic J45 adult and pediatric computational phantoms (Griffin et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series: Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System

et al. 2023

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Organ dosimetry data of the atomic bomb survivors and the resulting cancer risk models derived from these data are currently assessed within the DS02 dosimetry system developed through the Joint US-Japan Dosimetry Working Group. In DS02, the anatomical survivor models are limited to three hermaphroditic stylized phantoms-an adult (55 kg), a child (19.8 kg), and an infant (9.7 kg)-that were originally designed for the preceding DS86 dosimetry system. As such, organ doses needed for assessment of in-utero cancer risks to the fetus have continued to rely upon the use of the uterine wall in the adult non-pregnant stylized phantom as the dose surrogate for all fetal organs regardless of gestational age. To address these limitations, the Radiation Effects Research Foundation (RERF) Working Group on Organ Dose (WGOD) has established the J45 (Japan 1945) series of high-resolution voxel phantoms, which were derived from the UF/NCI series of hybrid phantoms and scaled to match mid-1940s Japanese body morphometries. The series includes male and female phantoms-newborn to adult-and four pregnant female phantoms at gestational ages of 8, 15, 25, and 38 wk post-conception. In previous studies, we have reported organ dose differences between those reported by the DS02 system and those computed by the WGOD using 3D Monte Carlo radiation transport simulations of atomic bomb gamma-ray and neutron fields for the J45 phantoms series in their traditional "stand-ing" posture, with some variations in their facing direction relative to the bomb hypocenter. In this present study, we present the J45 pregnant female phantoms in both a "kneeling" and "lying" posture and assess the dosimetric impact of these more anatomically realistic survivor models in comparison to current organ doses given by the DS02 system. For the kneeling phantoms facing the bomb hypocenter, organ doses from bomb source photon spectra were shown to be overestimated by the DS02 system by up to a factor of 1.45 for certain fetal organs and up to a factor of 1.17 for maternal organs. For lying phantoms with their feet in the direction of the hypocenter, fetal organ doses from bomb source photon spectra were underestimated by the DS02 system by factors as low as 0.77, while maternal organ doses were overestimated by up to a factor of 1.38. Organs doses from neutron contributions to the radiation fields exhibited an increasing overestimation by the DS02 stylized phantoms as gestational age increased. These discrepancies are most evident in fetal organs that are more posterior within the mother's womb, such as the fetal brain. Further analysis revealed that comparison of these postures to the original standing posture indicate significant dose differences for both maternal and fetal organ doses depending on the type of irradiation. Results from this study highlight the degree to which the existing DS02 system can differ from organ dosimetry based upon 3D radiation transport simulations using more anatomically realistic models of those survivors exposed during pregnancy.

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“…To improve the accuracy of the dose estimation, we need to update the transmission factor from shielded kerma to organ dose by reflecting the development [ 42 , 43 ] and considering studies [ 44 ] on a more detailed Japanese phantom. In addition, we should also consider the elevation of the individual survivors during the bombing; Cullings et al.…”

Section: Introductionmentioning

confidence: 99%

Prospects and status of the dosimetry system for atomic bomb survivor cohort study conducted at Research Institute for Radiation Biology and Medicine of Hiroshima University

Hirota

Yasuda

Kawakami

et al. 2021

Journal of Radiation Research

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The Research Institute for Radiation Biology and Medicine (RIRBM) of Hiroshima University has been conducting a cohort study of atomic bomb survivors (ABS). Cohort members include those who were issued an Atomic Bomb Health Handbook from the Hiroshima local government. A series of dosimetry systems for the ABS were developed at RIRBM to evaluate the health effects associated with radiation exposure. The framework used to estimate individual doses in our dosimetry systems for ABS is mainly based on the Dosimetry System 86, and its revisions developed by the Radiation Effect Research Foundation. This article describes the design and computational principles for the dosimetry systems in RIRBM and the history of the revisions, from the first version of the system, ABS93D, to the most recent version, ABS16D. We then provide a perspective for further improvement and application of the dosimetry system.

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Dosimetric Impact of a New Computational Voxel Phantom Series for the Japanese Atomic Bomb Survivors: Methodological Improvements and Organ Dose Response Functions

Cited by 6 publications

References 18 publications

Japanese pediatric and adult atomic bomb survivor dosimetry: potential improvements using the J45 phantom series and modern Monte Carlo transport

Japanese pediatric and adult atomic bomb survivor dosimetry: potential improvements using the J45 phantom series and modern Monte Carlo transport

Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series: Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System

Prospects and status of the dosimetry system for atomic bomb survivor cohort study conducted at Research Institute for Radiation Biology and Medicine of Hiroshima University

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