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Yeom YS, Griffin K, Han H, Choi C, Shin B, Nguyen TT, Kim CH, Lee C. Dose conversion coefficients for neutron external exposures with five postures: walking, sitting, bending, kneeling, and squatting. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:317-328. [PMID: 33704559 PMCID: PMC9923510 DOI: 10.1007/s00411-021-00900-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
In a previous study, posture-dependent dose coefficients (DCs) for photon external exposures were calculated using the adult male and female mesh-type reference computational phantoms (MRCPs) of the International Commission on Radiological Protection (ICRP) that had been transformed into five non-standing postures (i.e. walking, sitting, bending, kneeling, and squatting). As an extension, the present study was conducted to establish another DC dataset for external exposures to neutrons by performing Monte Carlo radiation transport simulations with the adult male and female MRCPs in the five non-standing postures. The resulting dataset included the DCs for absorbed doses (i.e., organ/tissue-averaged absorbed doses) delivered to 29 individual organs/tissues, and for effective doses for neutron energies ranging from 10-9 to 104 MeV in six irradiation geometries: antero-posterior (AP), posteroanterior (PA), left-lateral (LLAT), right-lateral (RLAT), rotational (ROT), and isotropic (ISO) geometries. The comparison of DCs for the non-standing MRCPs with those of the standing MRCPs showed significant differences. In the lateral irradiation geometries, for example, the standing MRCPs overestimate the breast DCs of the squatting MRCPs by up to a factor of 4 due to the different arm positions but underestimate the gonad DCs by up to about 17 times due to the different leg positions. The impact of different postures on effective doses was generally less than that on organ doses but still significant; for example, the standing MRCPs overestimate the effective doses of the bending MRCPs only by 20% in the AP geometry at neutron energies less than 50 MeV, but underestimate those of the kneeling MRCPs by up to 40% in the lateral geometries at energies less than 0.1 MeV.
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Affiliation(s)
- Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Keith Griffin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
| | - Chansoo Choi
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
| | - Bangho Shin
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
| | - Thang Tat Nguyen
- School of Nuclear Engineering and Environmental Physics, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hai Ba Trung District, Hanoi, Vietnam
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea.
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
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Sivabhaskar S, Perry A, Dewji S. Comparison of Neutron Organ and Effective Dose Coefficients for PIMAL Stylized Phantoms in Bent Postures in Cranial and Caudal Irradiation Geometries. HEALTH PHYSICS 2021; 120:559-572. [PMID: 33470713 DOI: 10.1097/hp.0000000000001382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
ABSTRACT Radiation dose estimations in the human body are performed using computational reference phantoms, which are anatomical representations of the human body. In previous studies, dose reconstructions have been performed focusing primarily on phantoms in an upright posture, which limits the accuracy of the dose estimations for postures observed in realistic work settings. In this work, the International Commission on Radiological Protection (ICRP) Publication 103 recommendations for monoenergetic neutron plane sources directed downward from above the head (cranial) and upward from below the feet (caudal) for adult female and male reference phantoms were used to calculate organ absorbed and effective dose coefficients. The Phantom with Moving Arms and Legs (PIMAL) and the Monte Carlo N-Particle (MCNP) radiation transport code were used to compute organ-absorbed dose and effective dose coefficients for the upright, half-bent (45°), and full-bent (90°) phantom postures. The doses calculated for each of the articulated positions were compared to those calculated for the upright posture by computing the ratios of the coefficients (45°/upright and 90°/upright). These ratios were used to assess the effectiveness of upright phantoms in providing a comparable estimate when conducting dose estimations and dose reconstructions for articulated positions. This work compiling neutron cranial and caudal posture-specific dose coefficients completes the series of dose coefficients computed for posture-specific ICRP Publication 116 irradiation geometries for monoenergetic photons and neutrons, in addition to cranial and caudal monoenergetic photons. Results reported demonstrated that organ-absorbed dose coefficients for most of the organs in the CRA and CAU irradiation geometries were significantly higher for the bent phantoms than for the upright phantom. Since the upright phantom underestimates the organ-absorbed dose, this demonstrates the impact of posture while performing dose calculations. Organ doses reported in past neutron dose coefficient data were found to omit effects from neutron resonances at energies of 0.435, 1.0, and 3.21 MeV from 16O in tissue. Reported data notes as high as 60% underestimation for neutron organ-absorbed doses, specifically at the neutron resonance energy region omitted by smoothing. Ongoing studies are examining the effect of resonances on reported neutron organ-absorbed dose coefficients in ICRP 116 geometries.
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Affiliation(s)
| | - Alexander Perry
- Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843
| | - Shaheen Dewji
- Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843
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Pereira LO, Freitas RP, Ferreira DS, Felix VS, Gonçalves EA, Pimenta AR, de Sousa Dutra R, Xavier da Silva A. Dose distribution in boron neutron capture therapy for the treatment of brain cancer. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2019.108611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bales K, Dewji S. Comparison of Organ and Effective Photon Dose Coefficients for Reference Phantoms in Articulated and Upright Postures in Cranial and Caudal Irradiation Geometries. HEALTH PHYSICS 2019; 116:599-606. [PMID: 30624352 DOI: 10.1097/hp.0000000000000985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Traditionally, dose estimations have been performed predominantly using anthropomorphic phantoms in an upright posture. However, an exclusively upright posture could reduce accuracy when estimating organ absorbed and effective doses for exposures in realistic postures. In this work, effective dose coefficients were computed using International Commission on Radiological Protection Publication 103 recommendations for monoenergetic photon plane sources (0.05-20 MeV) directed upward from below the feet (caudal) and downward from above the head (cranial) for articulated adult male and female stylized phantoms. The Monte Carlo radiation transport code and the Phantom With Moving Arms and Legs were used to calculate organ absorbed dose and effective dose coefficients for upright and two bent (45° and 90°) phantom postures. The resulting coefficients for the bent phantoms were compared to those for the upright phantoms to determine whether the upright phantoms provide a comparable and conservative estimate when conducting dose estimations/reconstructions. For the caudal source, most organs received higher doses when in a bent posture. For the cranial source, the breast, brain, and eyes received lower doses in the bent compared to the upright posture, while all other organs received higher doses. The effective doses for the articulated phantoms were higher than for the upright posture for both irradiation geometries, which could have implications when using the traditional model to estimate or reconstruct radiation doses during actual exposures.
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Affiliation(s)
- Kathryn Bales
- Oak Ridge National Laboratory, Center for Radiation Protection Knowledge, Oak Ridge, TN
- University of Tennessee-Knoxville, Department of Nuclear Engineering, Knoxville, TN
| | - Shaheen Dewji
- Department of Nuclear Engineering, Center for Nuclear Security Science and Policy Initiatives, Texas A&M University, College Station, TX
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Yeom YS, Han H, Choi C, Nguyen TT, Shin B, Lee C, Kim CH. Posture-dependent dose coefficients of mesh-type ICRP reference computational phantoms for photon external exposures. ACTA ACUST UNITED AC 2019; 64:075018. [DOI: 10.1088/1361-6560/ab0917] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Alves MC, Santos WS, Lee C, Bolch WE, Hunt JG, Júnior ABC. Conversion Coefficients for Proton Beams using Standing and Sitting Male Hybrid Computational Phantom Calculated in Idealized Irradiation Geometries. RADIATION PROTECTION DOSIMETRY 2017; 175:75-86. [PMID: 27664429 PMCID: PMC6257014 DOI: 10.1093/rpd/ncw271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 08/21/2016] [Accepted: 08/31/2016] [Indexed: 06/06/2023]
Abstract
The aim of this study was the calculation of conversion coefficients for absorbed doses per fluence (DT/Φ) using the sitting and standing male hybrid phantom (UFH/NCI) exposure to monoenergetic protons with energy ranging from 2 MeV to 10 GeV. Sex-averaged effective dose per fluence (E/Φ) using the results of DT/Φ for the male and female hybrid phantom in standing and sitting postures were also calculated. Results of E/Φ of UFH/NCI standing phantom were also compared with tabulated effective dose conversion coefficients provided in ICRP publication 116. To develop an exposure scenario implementing the male UFH/NCI phantom in sitting and standing postures was used the radiation transport code MCNPX. Whole-body irradiations were performed using the recommended irradiation geometries by ICRP publication 116 antero-posterior (AP), postero-anterior (PA), right and left lateral, rotational (ROT) and isotropic (ISO). In most organs, the conversion coefficients DT/Φ were similar for both postures. However, relative differences were significant for organs located in the lower abdominal region, such as prostate, testes and urinary bladder, especially in the AP geometry. Results of effective dose conversion coefficients were 18% higher in the standing posture of the UFH/NCI phantom, especially below 100 MeV in AP and PA. In lateral geometry, the conversion coefficients values below 20 MeV were 16% higher in the sitting posture. In ROT geometry, the differences were below 10%, for almost all energies. In ISO geometry, the differences in E/Φ were negligible. The results of E/Φ of UFH/NCI phantom were in general below the results of the conversion coefficients provided in ICRP publication 116.
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Affiliation(s)
- M. C. Alves
- Departamento de Física, Universidade Federal de Sergipe; Campus Prof. José Aloísio de Campos, 49.100-000, São Cristóvão – SE, Brazil
| | - W. S. Santos
- Instituto de Física, Universidade Federal de Uberlândia (INFIS/UFU), Caixa Postal 593, 38400-902 Uberlândia, MG, Brazil
| | - C. Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD 20852, USA
| | - W. E. Bolch
- Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611-8300, USA
| | - J. G. Hunt
- Dosimetry Division, Instituto de Radioproteção e Dosimetria, Rio de Janeiro, RJ 22783-127, Brazil
| | - A. B. Carvalho Júnior
- Departamento de Física, Universidade Federal de Sergipe; Campus Prof. José Aloísio de Campos, 49.100-000, São Cristóvão – SE, Brazil
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Alves MC, Galeano DC, Santos WS, Lee C, Bolch WE, Hunt JG, da Silva AX, Carvalho AB. Comparison of the effective dose rate to aircrew members using hybrid computational phantoms in standing and sitting postures. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2016; 36:885-901. [PMID: 27798410 DOI: 10.1088/0952-4746/36/4/885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Aircraft crew members are occupationally exposed to considerable levels of cosmic radiation at flight altitudes. Since aircrew (pilots and passengers) are in the sitting posture for most of the time during flight, and up to now there has been no data on the effective dose rate calculated for aircrew dosimetry in flight altitude using a sitting phantom, we therefore calculated the effective dose rate using a phantom in the sitting and standing postures in order to compare the influence of the posture on the radiation protection of aircrew members. We found that although the better description of the posture in which the aircrews are exposed, the results of the effective dose rate calculated with the phantom in the sitting posture were very similar to the results of the phantom in the standing posture. In fact we observed only a 1% difference. These findings indicate the adequacy of the use of dose conversion coefficients for the phantom in the standing posture in aircrew dosimetry. We also validated our results comparing the effective dose rate obtained using the standing phantom with values reported in the literature. It was observed that the results presented in this study are in good agreement with other authors (the differences are below 30%) who have measured and calculated effective dose rates using different phantoms.
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Affiliation(s)
- M C Alves
- Departamento de Física, Universidade Federal de Sergipe; Campus Prof. José Aloísio de Campos, 49.100-000, São Cristóvão, SE, Brazil
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Galeano D, Santos W, Alves M, Souza D, Carvalho A. Fluence-to-dose conversion coefficients based on the posture modification of Adult Male (AM) and Adult Female (AF) reference phantoms of ICRP 110. Radiat Phys Chem Oxf Engl 1993 2016. [DOI: 10.1016/j.radphyschem.2015.12.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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