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Correa-Alfonso CM, Withrow JD, Domal SJ, Xing S, Shin J, Grassberger C, Paganetti H, Bolch WE. A mesh-based model of liver vasculature: implications for improved radiation dosimetry to liver parenchyma for radiopharmaceuticals. EJNMMI Phys 2022; 9:28. [PMID: 35416550 PMCID: PMC9008118 DOI: 10.1186/s40658-022-00456-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/28/2022] [Indexed: 12/05/2022] Open
Abstract
Purpose To develop a model of the internal vasculature of the adult liver and demonstrate its application to the differentiation of radiopharmaceutical decay sites within liver parenchyma from those within organ blood. Method Computer-generated models of hepatic arterial (HA), hepatic venous (HV), and hepatic portal venous (HPV) vascular trees were algorithmically created within individual lobes of the ICRP adult female and male livers (AFL/AML). For each iteration of the algorithm, pressure, blood flow, and vessel radii within each tree were updated as each new vessel was created and connected to a viable bifurcation site. The vascular networks created inside the AFL/AML were then tetrahedralized for coupling to the PHITS radiation transport code. Specific absorbed fractions (SAF) were computed for monoenergetic alpha particles, electrons, positrons, and photons. Dual-region liver models of the AFL/AML were proposed, and particle-specific SAF values were computed assuming radionuclide decays in blood within two locations: (1) sites within explicitly modeled hepatic vessels, and (2) sites within the hepatic blood pool residing outside these vessels to include the capillaries and blood sinuses. S values for 22 and 10 radionuclides commonly used in radiopharmaceutical therapy and imaging, respectively, were computed using the dual-region liver models and compared to those obtained in the existing single-region liver model. Results Liver models with virtual vasculatures of ~ 6000 non-intersecting straight cylinders representing the HA, HPV, and HV circulations were created for the ICRP reference. For alpha emitters and for beta and auger-electron emitters, S values using the single-region models were approximately 11% (AML) to 14% (AFL) and 11% (AML) to 13% (AFL) higher than the S values obtained using the dual-region models, respectively. Conclusions The methodology employed in this study has shown improvements in organ parenchymal dosimetry through explicit consideration of blood self-dose for alpha particles (all energies) and for electrons at energies below ~ 100 keV.
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Affiliation(s)
- Camilo M Correa-Alfonso
- Medical Physics Program, College of Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Julia D Withrow
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611-6550, USA
| | - Sean J Domal
- Medical Physics Program, College of Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Shu Xing
- Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jungwook Shin
- Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02115, USA.,Radiation Epidemiology Branch, National Cancer Institute, Rockville, MD, 21704, USA
| | - Clemens Grassberger
- Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Harald Paganetti
- Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Wesley E Bolch
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611-6550, USA.
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Kollitz E, Han H, Kim CH, Pinto M, Schwarz M, Riboldi M, Kamp F, Belka C, Newhauser WD, Dedes G, Parodi K. A patient-specific hybrid phantom for calculating radiation dose and equivalent dose to the whole body. Phys Med Biol 2021; 67. [PMID: 34969024 DOI: 10.1088/1361-6560/ac4738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/30/2021] [Indexed: 11/12/2022]
Abstract
OBJECTIVE As cancer survivorship increases, there is growing interest in minimizing the late effects of radiation therapy such as radiogenic second cancer, which may occur anywhere in the body. Assessing the risk of late effects requires knowledge of the dose distribution throughout the whole body, including regions far from the treatment field, beyond the typical anatomical extent of clinical CT scans. APPROACH A hybrid phantom was developed which consists of in-field patient CT images extracted from ground truth whole-body CT (WBCT) scans, out-of-field mesh phantoms scaled to basic patient measurements, and a blended transition region. Four of these hybrid phantoms were created, representing male and female patients receiving proton therapy treatment in pelvic and cranial sites. To assess the performance of the hybrid approach, we simulated treatments using the hybrid phantoms, the scaled and unscaled mesh phantoms, and the ground truth whole-body CTs. We calculated absorbed dose and equivalent dose in and outside of the treatment field, with a focus on neutrons induced in the patient by proton therapy. Proton and neutron dose was calculated using a general purpose Monte Carlo code. MAIN RESULTS The hybrid phantom provided equal or superior accuracy in calculated organ dose and equivalent dose values relative to those obtained using the mesh phantoms in 78% in all selected organs and calculated dose quantities. Comparatively the default mesh and scaled mesh were equal or superior to the other phantoms in 21% and 28% of cases respectively. SIGNIFICANCE The proposed methodology for hybrid synthesis provides a tool for whole-body organ dose estimation for individual patients without requiring CT scans of their entire body. Such a capability would be useful for personalized assessment of late effects and risk-optimization of treatment plans.
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Affiliation(s)
- Erika Kollitz
- Department of Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Garching, Bayern, 85748, GERMANY
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seongdong-gu, Seoul, 04763, Korea (the Republic of)
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seongdong-gu, Seoul, 04763, Korea (the Republic of)
| | - Marco Pinto
- Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Garching, Bayern, 85748, GERMANY
| | - Marco Schwarz
- Provincia autonoma di Trento Azienda Provinciale per i Servizi Sanitari, Via Alcide Degasperi 79, Trento, Trentino-Alto Adige, 38123, ITALY
| | - Marco Riboldi
- Department of Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Munchen, Bayern, 85748, GERMANY
| | - Florian Kamp
- Radiotherapy, Klinikum der Universitat Munchen, Marchioninistraße 15, Munich, 81377, GERMANY
| | - Claus Belka
- Department of Radiation Oncology, Klinikum der Universitat Munchen, Marchioninistraße 15, Munchen, Bayern, 81377, GERMANY
| | - Wayne David Newhauser
- Department of Physics & Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, Louisiana, 70803, UNITED STATES
| | - Georgios Dedes
- Department of Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Munchen, Bayern, 85748, GERMANY
| | - Katia Parodi
- Experimental Physics Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Munchen, Bayern, 85748, GERMANY
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Shin B, Choi C, Yeom YS, Han H, Nguyen TT, Ha S, Moon S, Son G, Kim CH, Chung BS. Detailed tooth models for ICRP mesh-type reference computational phantoms. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:669-688. [PMID: 33647886 DOI: 10.1088/1361-6498/abeaf9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
For use in electron paramagnetic resonance dosimetry with tooth enamel, in the present study, very detailed mesh-type tooth models composed of 198 individual tooth models (i.e. newborn: 20; 1 year: 28; 5 years: 48; 10 years: 38; 15 years: 32; and adult: 32) were developed for each sex. The developed tooth models were then implanted in the International Commission on Radiological Protection pediatric and adult mesh-type reference computational phantoms and used to calculate tooth enamel doses, by Monte Carlo simulations with Geant4, for external photon exposures in several idealized irradiation geometries. The calculated dose values were then compared to investigate the dependency of the enamel dose on the age and sex of the phantom and the sites of the teeth. The results of the present study generally show that, if the photon energy is low (i.e. <0.1 MeV), the enamel dose is significantly affected by the age and sex of the phantom and also the sites of the teeth used for dose calculation; the differences are frequently greater than a few times or even orders of magnitude. However, with a few exceptions, the enamel dose was hardly affected by these parameters for energies between 0.1 and 3 MeV. For energies >3 MeV, moderate differences were observed (i.e., up to a factor of two), due to the existence of dose build-up in the head of the phantom for high-energy photons. The calculated dose values were also compared with those of the previous studies where voxel and mathematical models were used to calculate the enamel doses. The results again show significant differences at low energies, e.g., up to ∼3500 times at 0.015 MeV, which are mainly due to the differences in the level of tooth-modeling detailedness.
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Affiliation(s)
- Bangho Shin
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Chansoo Choi
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Thang Tat Nguyen
- Department of Nuclear Engineering and Environmental Physics, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Sangseok Ha
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Sungho Moon
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Gahee Son
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Beom Sun Chung
- Department of Anatomy, Yonsei University Wonju College of Medicine, Wonju, South Korea
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Choi C, Shin B, Yeom YS, Nguyen TT, Han H, Ha S, Chung BS, Bolch WE, Kim CH. Development of paediatric mesh-type reference computational phantom series of International Commission on Radiological Protection. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:S160-S170. [PMID: 34082408 DOI: 10.1088/1361-6498/ac0801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/03/2021] [Indexed: 06/12/2023]
Abstract
Very recently, Task Group 103 of the International Commission on Radiological Protection (ICRP) completed the development of the paediatric mesh-type reference computational phantoms (MRCPs) comprising ten phantoms (newborn, one year-old, five year-old, ten year-old, and fifteen year-old males and females). The paediatric MRCPs address the limitations of ICRPPublication 143's paediatric reference computational phantoms, which are in voxel format, stemming from the nature of the voxel geometry and the limited voxel resolutions. The paediatric MRCPs were constructed by converting the voxel-type reference phantoms to a high-quality mesh format with substantial enhancements in the detailed anatomy of the small and complex organs and tissues (e.g. bones, lymphatic nodes, and extra-thoracic region). Besides, the paediatric MRCPs were developed in consideration of the intra-organ blood contents and by modelling the micron-thick target and source regions of the skin, lens, urinary bladder, alimentary tract organs, and respiratory tract organs prescribed by the ICRP. For external idealised exposures, the paediatric MRCPs provide very similar effective dose coefficients (DCEs) to those from the ICRP-143 phantoms but significantly different values for weakly penetrating radiations (e.g. the difference of ∼20 000 times for 10 keV electron beams). This paper introduces the developed paediatric MRCPs with a brief explanation of the construction process. Then, it discusses their computational performance in Geant4, PHITS, and MCNP6 in terms of memory usage and computation speed and their impact on dose calculations by comparing their calculated values of DCEs for external exposures with those of the voxel-type reference phantoms.
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Affiliation(s)
- Chansoo Choi
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Bangho Shin
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD, United States of America
| | - Thang Tat Nguyen
- Department of Nuclear Engineering and Environmental Physics, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Sangseok Ha
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Beom Sun Chung
- Department of Anatomy, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Wesley E Bolch
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States of America
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
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Han H, Yeom YS, Nguyen TT, Choi C, Shin B, Moon S, Ha S, Son G, Augusteyn R, Kim CH. Development of detailed pediatric eye models for lens dose calculations. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:305-325. [PMID: 33882468 DOI: 10.1088/1361-6498/abfa32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
The International Commission on Radiological Protection (ICRP) recently reduced the dose limit for the eye lens for occupational exposure from 150 mSv yr-1to 20 mSv yr-1, as averaged over defined periods of five years, with no annual dose in a single year exceeding 50 mSv, emphasizing the importance of the accurate estimation of lens dose. In the present study, for more accurate lens dosimetry, detailed eye models were developed for children and adolescents (newborns and 1, 5, 10, and 15 year olds), which were then incorporated into the pediatric mesh-type reference computational phantoms (MRCPs) and used to calculate lens dose coefficients (DCs) for photon and electron exposures. Finally, the calculated values were compared with those calculated with the adult MRCPs in order to determine the age dependence of the lens DCs. For photon exposures, the lens DCs of the pediatric MRCPs showed some sizable differences from those of the adult MRCPs at very low energies (10 and 15 keV), but the differences were all less than 35%, except for the posterior-anterior irradiation geometry, for which the lens dose is not of primary concern. For electron exposures, much larger differences were found. For the anterior-posterior (AP) and isotropic irradiation geometries, the largest differences between the lens DCs of the pediatric and adult phantoms were found in the energy range of 0.6-1 MeV, where the newborn lens DCs were larger by up to a factor of ∼5 than the adult. The lens DCs of the present study, which were calculated for the radiosensitive region of the lens, also were compared with those for the entire lens in the AP irradiation geometry. Our results showed that the DCs of the entire lens were similar to those of the radiosensitive region for 0.02-2 MeV photons and >2 MeV electrons, but that for the other energy ranges, significant differences were noticeable, i.e. 10%-40% for photons and up to a factor of ∼5 for electrons.
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Affiliation(s)
- Haegin Han
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Thang Tat Nguyen
- School of Nuclear Engineering and Environmental Physics, Hanoi University of Science and Technology, 1 Dai Co Viet Road, Hanoi, Vietnam
| | - Chansoo Choi
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Bangho Shin
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Sungho Moon
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Sangseok Ha
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Gahee Son
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Robert Augusteyn
- School of Optometry and Vision Science, University of New South Wales, Kensington, NSW 2052, Australia
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
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Choi C, Shin B, Yeom YS, Han H, Ha S, Moon S, Son G, Nguyen TT, Kim CH, Chung BS, Bolch WE. Development of skeletal systems for ICRP pediatric mesh-type reference computational phantoms. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:139-161. [PMID: 33401263 DOI: 10.1088/1361-6498/abd88d] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
In 2016, the International Commission on Radiological Protection (ICRP) launched Task Group 103 (TG 103) for the explicit purpose of developing a new generation of adult and pediatric reference computational phantoms, named 'mesh-type reference computational phantoms (MRCPs)', that can overcome the limitations of voxel-type reference computational phantoms (VRCPs) of ICRPPublications 110and143due to their finite voxel resolutions and the nature of voxel geometry. After completing the development of the adult MRCPs, TG 103 has started the development of pediatric MRCPs comprising 10 phantoms (male and female versions of the reference newborn, 1-year-old, 5-year-old, 10-year-old, and 15-year-old). As part of the TG 103 project, within the present study, the skeletal systems, one of the most important and complex organ systems of the body, were developed for each phantom age and sex. The developed skeletal systems, while closely preserving the original bone topology of the pediatric VRCPs, present substantial improvements in the anatomy of complex and/or small bones. In order to investigate the dosimetric impact of the developed skeletons, the average absorbed doses and the specific absorbed fractions for radiosensitive skeletal tissues (i.e. active marrow and bone endosteum) were computed for some selected external and internal exposure cases, which were then compared with those calculated with the skeletons of pediatric VRCPs. The comparison result showed that the dose values of the pediatric MRCPs were generally similar to those of the pediatric VRCPs for highly penetrating radiations (e.g. photons >200 keV); however, for weakly penetrating radiations (e.g. photons ⩽200 keV and electrons), significant differences up to a factor of 140 were observed.
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Affiliation(s)
- Chansoo Choi
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Bangho Shin
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Sangseok Ha
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Sungho Moon
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Gahee Son
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Thang Tat Nguyen
- School of Nuclear Engineering and Environmental Physics, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Beom Sun Chung
- Department of Anatomy, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Wesley E Bolch
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States of America
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