1
|
Yamada Y, Imaoka T, Iwasaki T, Kobayashi J, Misumi M, Sakai K, Sugihara T, Suzuki K, Tauchi H, Yasuda H, Yoshinaga S, Sasatani M, Tanaka S, Doi K, Tomita M, Iizuka D, Kakinuma S, Sasaki M, Kai M. Establishment and activity of the planning and acting network for low dose radiation research in Japan (PLANET): 2016-2023. JOURNAL OF RADIATION RESEARCH 2024; 65:561-574. [PMID: 39007844 PMCID: PMC11420843 DOI: 10.1093/jrr/rrae049] [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: 12/14/2023] [Revised: 03/28/2024] [Indexed: 07/16/2024]
Abstract
The Planning and Acting Network for Low Dose Radiation Research in Japan (PLANET) was established in 2017 in response to the need for an all-Japan network of experts. It serves as an academic platform to propose strategies and facilitate collaboration to improve quantitative estimation of health risks from ionizing radiation at low-doses and low-dose-rates. PLANET established Working Group 1 (Dose-Rate Effects in Animal Experiments) to consolidate findings from animal experiments on dose-rate effects in carcinogenesis. Considering international trends in this field as well as the situation in Japan, PLANET updated its priority research areas for Japanese low-dose radiation research in 2023 to include (i) characterization of low-dose and low-dose-rate radiation risk, (ii) factors to be considered for individualization of radiation risk, (iii) biological mechanisms of low-dose and low-dose-rate radiation effects and (iv) integration of epidemiology and biology. In this context, PLANET established Working Group 2 (Dose and Dose-Rate Mapping for Radiation Risk Studies) to identify the range of doses and dose rates at which observable effects on different endpoints have been reported; Working Group 3 (Species- and Organ-Specific Dose-Rate Effects) to consider the relevance of stem cell dynamics in radiation carcinogenesis of different species and organs; and Working Group 4 (Research Mapping for Radiation-Related Carcinogenesis) to sort out relevant studies, including those on non-mutagenic effects, and to identify priority research areas. These PLANET activities will be used to improve the risk assessment and to contribute to the revision of the next main recommendations of the International Commission on Radiological Protection.
Collapse
Affiliation(s)
- Yutaka Yamada
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tatsuhiko Imaoka
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Toshiyasu Iwasaki
- Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba 270-1194, Japan
| | - Junya Kobayashi
- Department of Radiological Sciences, School of Health Sciences at Narita, International University of Health and Welfare, 4-3, Kozunomori, Narita, Chiba 286-8686, Japan
| | - Munechika Misumi
- Department of Statistics, Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Kazuo Sakai
- Tokyo Healthcare University, 2-5-1 Higashiaoka, Meguro-ku, Tokyo 152-8558, Japan
| | - Takashi Sugihara
- Department of Radiobiology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho-mura, Kamikita-gun, Aomori 039-3212, Japan
| | - Keiji Suzuki
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Hiroshi Tauchi
- Department of Biological Sciences, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512, Japan
| | - Hiroshi Yasuda
- Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Shinji Yoshinaga
- Department of Environmetrics and Biometrics, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Megumi Sasatani
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Satoshi Tanaka
- Department of Radiobiology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho-mura, Kamikita-gun, Aomori 039-3212, Japan
| | - Kazutaka Doi
- Department of Radiation Regulatory Science Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Masanori Tomita
- Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba 270-1194, Japan
| | - Daisuke Iizuka
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Shizuko Kakinuma
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Michiya Sasaki
- Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko, Chiba 270-1194, Japan
| | - Michiaki Kai
- Nippon Bunri University, 1727-162 Ichiki, Oita, Oita 870-0397, Japan
| |
Collapse
|
2
|
Wilson C, Adams GG, Patel P, Windham K, Ennis C, Caffrey E. A Review of Recent Low-dose Research and Recommendations for Moving Forward. HEALTH PHYSICS 2024; 126:386-396. [PMID: 38568156 DOI: 10.1097/hp.0000000000001808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
ABSTRACT The linear no-threshold (LNT) model has been the regulatory "law of the land" for decades. Despite the long-standing use of LNT, there is significant ongoing scientific disagreement on the applicability of LNT to low-dose radiation risk. A review of the low-dose risk literature of the last 10 y does not provide a clear answer, but rather the body of literature seems to be split between LNT, non-linear risk functions (e.g., supra- or sub-linear), and hormetic models. Furthermore, recent studies have started to explore whether radiation can play a role in the development of several non-cancer effects, such as heart disease, Parkinson's disease, and diabetes, the mechanisms of which are still being explored. Based on this review, there is insufficient evidence to replace LNT as the regulatory model despite the fact that it contributes to public radiophobia, unpreparedness in radiation emergency response, and extreme cleanup costs both following radiological or nuclear incidents and for routine decommissioning of nuclear power plants. Rather, additional research is needed to further understand the implications of low doses of radiation. The authors present an approach to meaningfully contribute to the science of low-dose research that incorporates machine learning and Edisonian approaches to data analysis.
Collapse
Affiliation(s)
- Charles Wilson
- University of Alabama at Birmingham, School of Health Professions, Clinical and Diagnostic Sciences, Health Physics Program
| | - Grace G Adams
- Gryphon Scientific, LLC, 6930 Carrol Ave., Suite 810, Takoma Park, MD 20912
| | - Pooja Patel
- University of Alabama at Birmingham, School of Health Professions, Clinical and Diagnostic Sciences, Health Physics Program
| | - Kiran Windham
- University of Alabama at Birmingham, School of Health Professions, Clinical and Diagnostic Sciences, Health Physics Program
| | - Colby Ennis
- University of Alabama at Birmingham, School of Health Professions, Clinical and Diagnostic Sciences, Health Physics Program
| | - Emily Caffrey
- University of Alabama at Birmingham, School of Health Professions, Clinical and Diagnostic Sciences, Health Physics Program
| |
Collapse
|
3
|
Dahl H, Ballangby J, Tengs T, Wojewodzic MW, Eide DM, Brede DA, Graupner A, Duale N, Olsen AK. Dose rate dependent reduction in chromatin accessibility at transcriptional start sites long time after exposure to gamma radiation. Epigenetics 2023; 18:2193936. [PMID: 36972203 PMCID: PMC10054331 DOI: 10.1080/15592294.2023.2193936] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/08/2023] [Indexed: 03/29/2023] Open
Abstract
Ionizing radiation (IR) impact cellular and molecular processes that require chromatin remodelling relevant for cellular integrity. However, the cellular implications of ionizing radiation (IR) delivered per time unit (dose rate) are still debated. This study investigates whether the dose rate is relevant for inflicting changes to the epigenome, represented by chromatin accessibility, or whether it is the total dose that is decisive. CBA/CaOlaHsd mice were whole-body exposed to either chronic low dose rate (2.5 mGy/h for 54 d) or the higher dose rates (10 mGy/h for 14 d and 100 mGy/h for 30 h) of gamma radiation (60Co, total dose: 3 Gy). Chromatin accessibility was analysed in liver tissue samples using Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-Seq), both one day after and over three months post-radiation (>100 d). The results show that the dose rate contributes to radiation-induced epigenomic changes in the liver at both sampling timepoints. Interestingly, chronic low dose rate exposure to a high total dose (3 Gy) did not inflict long-term changes to the epigenome. In contrast to the acute high dose rate given to the same total dose, reduced accessibility at transcriptional start sites (TSS) was identified in genes relevant for the DNA damage response and transcriptional activity. Our findings link dose rate to essential biological mechanisms that could be relevant for understanding long-term changes after ionizing radiation exposure. However, future studies are needed to comprehend the biological consequence of these findings.
Collapse
Affiliation(s)
- Hildegunn Dahl
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Jarle Ballangby
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Torstein Tengs
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
- Division for Aquaculture, Department of breeding and genetics, Nofima, Ås, Norway
| | - Marcin W. Wojewodzic
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
- Department of Research, Section Molecular Epidemiology and Infections, Cancer Registry of Norway, Oslo, Norway
| | - Dag M. Eide
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Dag Anders Brede
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
- Faculty of Environmental Sciences and Natural Resource Management (MINA), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Anne Graupner
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Nur Duale
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Ann-Karin Olsen
- Division of Climate and Environmental Health, Department of Chemical Toxicology, Norwegian Institute of Public Health, Oslo, Norway
- Centre for Environmental Radiation (CERAD), Norwegian University of Life Sciences (NMBU), Ås, Norway
| |
Collapse
|
4
|
Harrison JD, Oatway WB, Brown IK, Hopewell JW. Health risks from radioactive particles on Cumbrian beaches near the Sellafield nuclear site. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2023; 43:031504. [PMID: 37339608 DOI: 10.1088/1361-6498/acdfd6] [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: 02/28/2023] [Accepted: 06/20/2023] [Indexed: 06/22/2023]
Abstract
A monitoring programme, in place since 2006, continues to recover radioactive particles (<2 mm diameter) and larger objects from the beaches of West Cumbria. The potential risks to members of the public using the beaches are mainly related to prolonged skin contact with or the inadvertent ingestion of small particles. Most particles are classified as either 'beta-rich' or 'alpha-rich' and are detected as a result of their caesium-137 or americium-241 content. Beta-rich particles generally also contain strontium-90, with90Sr:137Cs ratios of up to about 1:1, but typically <0.1:1. Alpha-rich particles contain plutonium isotopes, with Pu:241Amαratios usually around 0.5-0.6:1. 'Beta-rich' particles have the greatest potential to cause localised skin damage if held in stationary contact with the skin for prolonged periods. However, it is concluded that only particles of >106Bq of137Cs, with high90Sr:137Cs ratios, would pose a significant risk of causing acute skin ulceration. No particles of this level of activity have been found. Inadvertent ingestion of a particle will result in the absorption to blood of a small proportion of the radionuclide content of the particle. The subsequent retention of radionuclides in body organs and tissues presents a potential risk of the development of cancer. For 'beta-rich' particles with typical activities (mean 2 × 104Bq137Cs, Sr:Cs ratio of 0.1:1), the estimated committed effective doses are about 30µSv for adults and about 40µSv for 1 year old infants, with lower values for 'alpha-rich' particles of typical activities. The corresponding estimates of lifetime cancer incidence following ingestion for both particle types are of the order of 10-6for adults and up to 10-5for infants. These estimates are subject to substantial uncertainties but provide an indication of the low risks to members of the public.
Collapse
Affiliation(s)
- John D Harrison
- Oxford Brookes University, Faculty of Health and Life Sciences, Oxford OX3 0BP, United Kingdom
- UK Health Security Agency, Radiation, Chemical and Environmental Hazards Directorate, Chilton, Didcot, Oxon OX11 0RQ, United Kingdom
| | - Wayne B Oatway
- UK Health Security Agency, Radiation, Chemical and Environmental Hazards Directorate, Chilton, Didcot, Oxon OX11 0RQ, United Kingdom
| | - Iain K Brown
- UK Health Security Agency, Radiation, Chemical and Environmental Hazards Directorate, Chilton, Didcot, Oxon OX11 0RQ, United Kingdom
| | - John W Hopewell
- Green Temple College, University of Oxford, Oxford OX2 6HG, United Kingdom
- Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom
| |
Collapse
|
5
|
Boretti A. There is no reason to persist in the linear no-threshold (LNT) assumption. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2023; 266-267:107239. [PMID: 37393723 DOI: 10.1016/j.jenvrad.2023.107239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/21/2023] [Accepted: 06/27/2023] [Indexed: 07/04/2023]
Affiliation(s)
- Alberto Boretti
- Johnsonville Road, Johnsonville, Wellington, 6037, New Zealand.
| |
Collapse
|
6
|
Otsuka K, Iwasaki T. Insights into radiation carcinogenesis based on dose-rate effects in tissue stem cells. Int J Radiat Biol 2023; 99:1503-1521. [PMID: 36971595 DOI: 10.1080/09553002.2023.2194398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 03/16/2023] [Indexed: 03/29/2023]
Abstract
PURPOSE Increasing epidemiological and biological evidence suggests that radiation exposure enhances cancer risk in a dose-dependent manner. This can be attributed to the 'dose-rate effect,' where the biological effect of low dose-rate radiation is lower than that of the same dose at a high dose-rate. This effect has been reported in epidemiological studies and experimental biology, although the underlying biological mechanisms are not completely understood. In this review, we aim to propose a suitable model for radiation carcinogenesis based on the dose-rate effect in tissue stem cells. METHODS We surveyed and summarized the latest studies on the mechanisms of carcinogenesis. Next, we summarized the radiosensitivity of intestinal stem cells and the role of dose-rate in the modulation of stem-cell dynamics after irradiation. RESULTS Consistently, driver mutations can be detected in most cancers from past to present, supporting the hypothesis that cancer progression is initiated by the accumulation of driver mutations. Recent reports demonstrated that driver mutations can be observed even in normal tissues, which suggests that the accumulation of mutations is a necessary condition for cancer progression. In addition, driver mutations in tissue stem cells can cause tumors, whereas they are not sufficient when they occur in non-stem cells. For non-stem cells, tissue remodeling induced by marked inflammation after the loss of tissue cells is important in addition to the accumulation of mutations. Therefore, the mechanism of carcinogenesis differs according to the cell type and magnitude of stress. In addition, our results indicated that non-irradiated stem cells tend to be eliminated from three-dimensional cultures of intestinal stem cells (organoids) composed of irradiated and non-irradiated stem cells, supporting the stem-cell competition. CONCLUSIONS We propose a unique scheme in which the dose-rate dependent response of intestinal stem cells incorporates the concept of the threshold of stem-cell competition and context-dependent target shift from stem cells to whole tissue. The concept highlights four key issues that should be considered in radiation carcinogenesis: i.e. accumulation of mutations; tissue reconstitution; stem-cell competition; and environmental factors like epigenetic modifications.
Collapse
Affiliation(s)
- Kensuke Otsuka
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Tokyo, Japan
| | - Toshiyasu Iwasaki
- Strategy and Planning Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Tokyo, Japan
| |
Collapse
|
7
|
Caravaca J, Peter R, Yang J, Gunther C, Antonio Camara Serrano J, Nostrand C, Steri V, Seo Y. Comparison and calibration of dose delivered by 137Cs and x-ray irradiators in mice. Phys Med Biol 2022; 67:10.1088/1361-6560/ac9e88. [PMID: 36317316 PMCID: PMC9933773 DOI: 10.1088/1361-6560/ac9e88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/28/2022] [Indexed: 11/07/2022]
Abstract
Objective.The Office of Radiological Security, U.S. Department of Energy's National Nuclear Security Administration, is implementing a radiological risk reduction program which seeks to minimize or eliminate the use of high activity radiological sources, including137Cs, by replacing them with non-radioisotopic technologies, such as x-ray irradiators. The main goal of this paper is to evaluate the equivalence of the dose delivered by gamma- and x-ray irradiators in mice using experimental measurements and Monte Carlo simulations. We also propose a novel biophantom as anin situdose calibration method.Approach.We irradiated mouse carcasses and 3D-printed mouse biophantoms in a137Cs irradiator (Mark I-68) and an x-ray irradiator (X-Rad320) at three voltages (160 kVp, 225 kVp and 320 kVp) and measured the delivered radiation dose. A Geant4-based Monte Carlo model was developed and validated to provide a comprehensive picture of gamma- and x-ray irradiation in mice.Main Results.Our Monte Carlo model predicts a uniform dose delivered in soft-tissue for all the explored irradiation programs and in agreement with the absolute dose measurements. Our Monte Carlo model shows an energy-dependent difference between dose in bone and in soft tissue that decreases as photon energy increases. Dose rate depends on irradiator and photon energy. We observed a deviation of the measured dose from the target value of up to -9% for the Mark I-68, and up to 35% for the X-Rad320. The dose measured in the 3D-printed phantoms are equivalent to that in the carcasses within 6% uncertainty.Significance.Our results suggest that 320 kVp irradiation is a good candidate to substitute137Cs irradiation barring a few caveats. There is a significant difference between measured and targeted doses for x-ray irradiation that suggests a strong need forin situcalibration, which can be achieved with 3D-printed mouse biophantoms. A dose correction is necessary for bone doses, which can be provided by a Monte Carlo calculation. Finally, the biological implications of the differences in dose rates and dose per photon for the different irradiation methods should be carefully assessed for each small-animal irradiation experiment.
Collapse
Affiliation(s)
- Javier Caravaca
- Physics Research Laboratory, University of California, San Francisco, United States of America
| | - Robin Peter
- Physics Research Laboratory, University of California, San Francisco, United States of America
- Department of Nuclear Engineering, University of California, Berkeley, United States of America
| | - Jaewon Yang
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Chad Gunther
- C&C Irradiator Service, LLC, Washington, DC. United States of America
| | - Juan Antonio Camara Serrano
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, United States of America
| | | | - Veronica Steri
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, United States of America
| | - Youngho Seo
- Physics Research Laboratory, University of California, San Francisco, United States of America
- Department of Nuclear Engineering, University of California, Berkeley, United States of America
| |
Collapse
|
8
|
Lowe D, Roy L, Tabocchini MA, Rühm W, Wakeford R, Woloschak GE, Laurier D. Radiation dose rate effects: what is new and what is needed? RADIATION AND ENVIRONMENTAL BIOPHYSICS 2022; 61:507-543. [PMID: 36241855 PMCID: PMC9630203 DOI: 10.1007/s00411-022-00996-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/13/2022] [Indexed: 05/04/2023]
Abstract
Despite decades of research to understand the biological effects of ionising radiation, there is still much uncertainty over the role of dose rate. Motivated by a virtual workshop on the "Effects of spatial and temporal variation in dose delivery" organised in November 2020 by the Multidisciplinary Low Dose Initiative (MELODI), here, we review studies to date exploring dose rate effects, highlighting significant findings, recent advances and to provide perspective and recommendations for requirements and direction of future work. A comprehensive range of studies is considered, including molecular, cellular, animal, and human studies, with a focus on low linear-energy-transfer radiation exposure. Limits and advantages of each type of study are discussed, and a focus is made on future research needs.
Collapse
Affiliation(s)
- Donna Lowe
- UK Health Security Agency, CRCE Chilton, Didcot, OX11 0RQ, Oxfordshire, UK
| | - Laurence Roy
- Institut de Radioprotection Et de Sûreté Nucléaire, Fontenay-Aux-Roses, France
| | - Maria Antonella Tabocchini
- Istituto Nazionale i Fisica Nucleare, Sezione i Roma, Rome, Italy
- Istituto Superiore Di Sanità, Rome, Italy
| | - Werner Rühm
- Institute of Radiation Medicine, Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Richard Wakeford
- Centre for Occupational and Environmental Health, The University of Manchester, Manchester, M13 9PL, UK
| | - Gayle E Woloschak
- Department of Radiation Oncology, Northwestern University School of Medicine, Chicago, IL, USA.
| | - Dominique Laurier
- Institut de Radioprotection Et de Sûreté Nucléaire, Fontenay-Aux-Roses, France
| |
Collapse
|
9
|
Abstract
Radiation detriment is a concept developed by the International Commission on Radiological Protection to quantify the burden of stochastic effects from low-dose and/or low-dose-rate exposures to the human population. It is determined from the lifetime risks of cancer for a set of organs and tissues and the risk of heritable effects, taking into account the severity of the consequences. This publication provides a historical review of detriment calculation methodology since ICRP Publication 26, with details of the procedure developed in ICRP Publication 103, which clarifies data sources, risk models, computational methods, and rationale for the choice of parameter values. A selected sensitivity analysis was conducted to identify the parameters and calculation conditions that can be major sources of variation and uncertainty in the calculation of radiation detriment. It has demonstrated that sex, age at exposure, dose and dose-rate effectiveness factor, dose assumption in the calculation of lifetime risk, and lethality fraction have a substantial impact on radiation detriment values. Although the current scheme of radiation detriment calculation is well established, it needs to evolve to better reflect changes in population health statistics and progress in scientific understanding of radiation health effects. In this regard, some key parameters require updating, such as the reference population data and cancer severity. There is also room for improvement in cancer risk models based on the accumulation of recent epidemiological findings. Finally, the importance of improving the comprehensibility of the detriment concept and the transparency of its calculation process is emphasised.© 2022 ICRP. Published by SAGE.
Collapse
|
10
|
Yamaguchi M, Tatara Y, Nugraha ED, Ramadhani D, Tamakuma Y, Sato Y, Miura T, Hosoda M, Yoshinaga S, Syaifudin M, Kashiwakura I, Tokonami S. Detection of biological responses to low-dose radiation in humans. Free Radic Biol Med 2022; 184:196-207. [PMID: 35447332 DOI: 10.1016/j.freeradbiomed.2022.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/06/2022] [Accepted: 04/08/2022] [Indexed: 11/20/2022]
Abstract
It has been considered difficult to detect the biological effects of low-dose radiation exposure below approximately 100 mSv in humans. Serum proteomic analysis and oxidative modification profiling were conducted with blood samples collected from residents of a newly discovered high-level natural background radiation area (annual effective dose approximately 50 mSv y-1) and normal-level area (1.22 mSv y-1) in Mamuju, Indonesia, where many people have been living for generations. Dose-dependent oxidative modifications in amino acid sequences of human serum albumin, especially the 162nd and 356th tyrosine residues and 111th and 470th methionine residues, were found. None of these findings have been reported in humans exposed to chronic low-dose radiation. It can be used as a biomarker not only for the assessment of the presence or absence of radiation exposure but also for dose prediction in living organisms for chronic radiation. These results suggest that traces of radiation exposure are recorded in serum albumin and that there is a possibility of a new methodology that can evaluate biological responses below 100 mSv.
Collapse
Affiliation(s)
- Masaru Yamaguchi
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Yota Tatara
- Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Eka Djatnika Nugraha
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; Center for Technology of Radiation Safety and Metrology, National Nuclear Energy Agency, JI. Lebak Bulus Raya No. 49, Jakarta Selatan, 12440, Indonesia
| | - Dwi Ramadhani
- Center for Technology of Radiation Safety and Metrology, National Nuclear Energy Agency, JI. Lebak Bulus Raya No. 49, Jakarta Selatan, 12440, Indonesia
| | - Yuki Tamakuma
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Yoshiaki Sato
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Tomisato Miura
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Masahiro Hosoda
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| | - Shinji Yoshinaga
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Mukh Syaifudin
- Center for Technology of Radiation Safety and Metrology, National Nuclear Energy Agency, JI. Lebak Bulus Raya No. 49, Jakarta Selatan, 12440, Indonesia
| | - Ikuo Kashiwakura
- Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan; Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan.
| | - Shinji Tokonami
- Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori, 036-8564, Japan
| |
Collapse
|
11
|
Low-Dose-Rate Irradiation Suppresses the Expression of Cell Cycle-Related Genes, Resulting in Modification of Sensitivity to Anti-Cancer Drugs. Cells 2022; 11:cells11030501. [PMID: 35159310 PMCID: PMC8833988 DOI: 10.3390/cells11030501] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/24/2022] [Accepted: 01/30/2022] [Indexed: 02/06/2023] Open
Abstract
The biological effects of low-dose-rate (LDR) radiation exposure in nuclear power plant accidents and medical uses of ionizing radiation (IR), although being a social concern, remain unclear. In this study, we evaluated the effects of LDR-IR on global gene expression in human cells and aimed to clarify the mechanisms. RNA-seq analyses demonstrated that relatively low dose rates of IR modify gene expression levels in TIG-3 cells under normoxic conditions, but those effects were attenuated under hypoxia-mimicking conditions. Gene set enrichment analysis demonstrated that LDR-IR significantly decreased gene expression related to cell division, cell cycle, mitosis, and the Aurora kinase B and FOXM1 pathways. Quantitative RT-PCR confirmed the down-regulation of AURKB and FOXM1 genes in TIG-3 cells with LDR-IR or hypoxia-mimicking treatments without any dose-rate effect. Knock-down experiments suggested that HIF-1α and HIF-2α, as well as DEC1, participated in down-regulation of AURKB and FOXM1 under DFOM treatments, but to a lesser extent under LDR-IR treatment. FACS and microscopic analyses demonstrated that LDR-IR induced G0/G1 arrest and increased micronucleus or chromosome condensation. Finally, MTT assays demonstrated that LDR-IR decreased sensitivity to paclitaxel or barasertib in TIG-3 cells but not in A549 cells. In conclusion, LDR-IR modifies global gene expression and cell cycle control, resulting in a reduction of sensitivity to anti-cancer chemotherapy in non-cancer cells and thus a reduction in untoward effects (GA).
Collapse
|
12
|
Hooshmand S, Reed WM, Suleiman ME, Brennan PC. A review of screening mammography: The benefits and radiation risks put into perspective. J Med Imaging Radiat Sci 2021; 53:147-158. [PMID: 34969620 DOI: 10.1016/j.jmir.2021.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 12/28/2022]
Abstract
INTRODUCTION/BACKGROUND In medical imaging a benefit to risk analysis is required when justifying or implementing diagnostic procedures. Screening mammography is no exception and in particular concerns around the use of radiation to help diagnose cancer must be addressed. METHODS The Medline database and various established reports on breast screening and radiological protection were utilised to explore this review. RESULTS/DISCUSSION The benefit of screening is well argued; the ability to detect and treat breast cancer has led to a 91% 5-year survival rate and 497 deaths prevented from breast cancer amongst 100,000 screened women. Subsequently, screening guidelines by various countries recommend annual, biennial or triennial screening from ages somewhere between 40-74 years. Whilst the literature presents different perspectives on screening younger and older women, the current evidence of benefit for screening women <40 and ≥75 years is currently not strong. The radiation dose and associated risk delivered to each woman for a single examination is dependent upon age, breast density and breast thickness, however the average mean glandular dose is around 2.5-3 mGy, and this would result in 65 induced cancers and 8 deaths per 100,000 women over a screening lifetime from 40-74 years. This results in a ratio of lives saved to deaths from induced cancer of 62:1. CONCLUSION Therefore, compared to the potential mortality reduction achievable with screening mammography, the risk is small.
Collapse
Affiliation(s)
- Sahand Hooshmand
- Faculty of Medicine and Health, The Discipline of Medical Imaging Sciences, The University of Sydney, Susan Wakil Health Building (D18), Sydney, NSW 2050, Australia.
| | - Warren M Reed
- Faculty of Medicine and Health, The Discipline of Medical Imaging Sciences, The University of Sydney, Susan Wakil Health Building (D18), Sydney, NSW 2050, Australia
| | - Mo'ayyad E Suleiman
- Faculty of Medicine and Health, The Discipline of Medical Imaging Sciences, The University of Sydney, Susan Wakil Health Building (D18), Sydney, NSW 2050, Australia
| | - Patrick C Brennan
- Faculty of Medicine and Health, The Discipline of Medical Imaging Sciences, The University of Sydney, Susan Wakil Health Building (D18), Sydney, NSW 2050, Australia
| |
Collapse
|
13
|
Clement C, Rühm W, Harrison J, Applegate K, Cool D, Larsson CM, Cousins C, Lochard J, Bouffler S, Cho K, Kai M, Laurier D, Liu S, Romanov S. Keeping the ICRP recommendations fit for purpose. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:1390-1409. [PMID: 34284364 DOI: 10.1088/1361-6498/ac1611] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/20/2021] [Indexed: 05/23/2023]
Abstract
The International Commission on Radiological Protection (ICRP) has embarked on a review and revision of the system of Radiological Protection that will update the 2007 general recommendations in ICRPPublication 103. This is the beginning of a process that will take several years, involving open and transparent engagement with organisations and individuals around the world. While the system is robust and has performed well, it must adapt to address changes in science and society to remain fit for purpose. The aim of this paper is to encourage discussions on which areas of the system might gain the greatest benefit from review, and to initiate collaborative efforts. Increased clarity and consistency are high priorities. The better the system is understood, the more effectively it can be applied, resulting in improved protection and increased harmonisation. Many areas are identified for potential review including: classification of effects, with particular focus on tissue reactions; reformulation of detriment, potentially including non-cancer diseases; re-evaluation of the relationship between detriment and effective dose, and the possibility of defining detriments for males and females of different ages; individual variation in the response to radiation exposure; heritable effects; and effects and risks in non-human biota and ecosystems. Some of the basic concepts are also being considered, including the framework for bringing together protection of people and the environment, incremental improvements to the fundamental principles of justification and optimisation, a broader approach to protection of individuals, and clarification of the exposure situations introduced in 2007. In addition, ICRP is considering identifying where explicit incorporation of the ethical basis of the system would be beneficial, how to better reflect the importance of communications and stakeholder involvement, and further advice on education and training. ICRP invites responses on these and other areas relating to the review of the System of Radiological Protection.
Collapse
Affiliation(s)
- C Clement
- International Commission on Radiological Protection, 280 Slater Street, Ottawa, Ontario K1P 5S9, Canada
| | - W Rühm
- Helmholtz Center Munich German Research Center for Environmental Health, Neuherberg, Germany
| | - J Harrison
- Oxford Brookes University, Faculty of Health and Life Sciences, OX3 0BP Oxford, United Kingdom
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, OX11 0RQ Didcot, Oxon, United Kingdom
| | - K Applegate
- University of Kentucky College of Medicine, 800 Rose Street MN 150, Lexington, KY 40506, United States of America (retired)
| | - D Cool
- Electric Power Research Institute, Charlotte, NC, United States of America
| | - C-M Larsson
- Australian Radiation Protection and Nuclear Safety Agency, PO Box 655, Miranda, NSW 1490, Australia
| | - C Cousins
- International Commission on Radiological Protection, 280 Slater Street, Ottawa, Ontario K1P 5S9, Canada
| | - J Lochard
- Nagasaki University, 1-14 Bunkyomachi, Nagasaki 852-8521, Japan
| | - S Bouffler
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, OX11 0RQ Didcot, Oxon, United Kingdom
| | - K Cho
- Korea Institute of Nuclear Safety, PO Box 114, Yuseong, Daejeon 305-338, Korea
| | - M Kai
- Nippon Bunri University, 1727 Ichigi, Ōita 870-0397, Japan
| | - D Laurier
- Institut de radioprotection et de Sûreté Nucléaire, BP 17-92262 Fontenay-aux-Roses Cedex, 31 avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, Île-de-France, France
| | - S Liu
- China Institute of Atomic Energy, PO Box 275 (1), Beijing CN-102413, People's Republic of China
| | - S Romanov
- Southern Urals Biophysics Institute, Ozyorsk, Chelyabinsk region, Russia
| |
Collapse
|
14
|
Laurier D, Rühm W, Paquet F, Applegate K, Cool D, Clement C. Areas of research to support the system of radiological protection. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:519-530. [PMID: 34657188 PMCID: PMC8522113 DOI: 10.1007/s00411-021-00947-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/05/2021] [Indexed: 05/07/2023]
Abstract
This document presents the ICRP's updated vision on "Areas of Research to Support the System of Radiological Protection", which have been previously published in 2017. It aims to complement the research priorities promoted by other relevant international organisations, with the specificity of placing them in the perspective of the evolution of the System of Radiological Protection. This document contributes to the process launched by ICRP to review and revise the System of Radiological Protection that will update the 2007 General Recommendations in ICRP Publication 103.
Collapse
Affiliation(s)
- D Laurier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France
| | - W Rühm
- Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany.
| | - F Paquet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Cadarache, France
| | - K Applegate
- University of Kentucky College of Medicine, Lexington, KY, USA
| | - D Cool
- International Commission on Radiological Protection (ICRP) Vice-Chair, Charlotte, NC, USA
| | - C Clement
- International Commission on Radiological Protection (ICRP), Ottawa, ON, Canada
| |
Collapse
|
15
|
Walsh L, Shore R, Azizova TV, Rühm W. On the choice of methodology for evaluating dose-rate effects on radiation-related cancer risks. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:493-500. [PMID: 34170393 PMCID: PMC8310494 DOI: 10.1007/s00411-021-00920-y] [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: 05/13/2021] [Accepted: 06/17/2021] [Indexed: 05/06/2023]
Abstract
Recently, several compilations of individual radiation epidemiology study results have aimed to obtain direct evidence on the magnitudes of dose-rate effects on radiation-related cancer risks. These compilations have relied on meta-analyses of ratios of risks from low dose-rate studies and matched risks from the solid cancer Excess Relative Risk models fitted to the acutely exposed Japanese A-bomb cohort. The purpose here is to demonstrate how choices of methodology for evaluating dose-rate effects on radiation-related cancer risks may influence the results reported for dose-rate effects. The current analysis is intended to address methodological issues and does not imply that the authors recommend a particular value for the dose and dose-rate effectiveness factor. A set of 22 results from one recent published study has been adopted here as a test set of data for applying the many different methods described here, that nearly all produced highly consistent results. Some recently voiced concerns, involving the recalling of the well-known theoretical point-the ratio of two normal random variables has a theoretically unbounded variance-that could potentially cause issues, are shown to be unfounded when aimed at the published work cited and examined in detail here. In the calculation of dose-rate effects for radiation protection purposes, it is recommended that meta-estimators should retain the full epidemiological and dosimetric matching information between the risks from the individual low dose-rate studies and the acutely exposed A-bomb cohort and that a regression approach can be considered as a useful alternative to current approaches.
Collapse
Affiliation(s)
- Linda Walsh
- Department of Physics, Science Faculty, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Roy Shore
- Department of Population Health, New York University Grossman School of Medicine, New York, USA
| | - Tamara V. Azizova
- Southern Urals Biophysics Institute, Ozyorskoe shosse 19, Ozyorsk, Chelyabinsk region 456780 Russia
| | - Werner Rühm
- Institute of Radiation Medicine, Helmholtz Zentrum München- German Research Center for Environmental Health, 85764 Neuherberg, Germany
| |
Collapse
|
16
|
Walsh L, Hafner L, Straube U, Ulanowski A, Fogtman A, Durante M, Weerts G, Schneider U. A bespoke health risk assessment methodology for the radiation protection of astronauts. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:213-231. [PMID: 33929575 PMCID: PMC8116305 DOI: 10.1007/s00411-021-00910-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/10/2021] [Indexed: 05/05/2023]
Abstract
An alternative approach that is particularly suitable for the radiation health risk assessment (HRA) of astronauts is presented. The quantity, Radiation Attributed Decrease of Survival (RADS), representing the cumulative decrease in the unknown survival curve at a certain attained age, due to the radiation exposure at an earlier age, forms the basis for this alternative approach. Results are provided for all solid cancer plus leukemia incidence RADS from estimated doses from theoretical radiation exposures accumulated during long-term missions to the Moon or Mars. For example, it is shown that a 1000-day Mars exploration mission with a hypothetical mission effective dose of 1.07 Sv at typical astronaut ages around 40 years old, will result in the probability of surviving free of all types of solid cancer and leukemia until retirement age (65 years) being reduced by 4.2% (95% CI 3.2; 5.3) for males and 5.8% (95% CI 4.8; 7.0) for females. RADS dose-responses are given, for the outcomes for incidence of all solid cancer, leukemia, lung and female breast cancer. Results showing how RADS varies with age at exposure, attained age and other factors are also presented. The advantages of this alternative approach, over currently applied methodologies for the long-term radiation protection of astronauts after mission exposures, are presented with example calculations applicable to European astronaut occupational HRA. Some tentative suggestions for new types of occupational risk limits for space missions are given while acknowledging that the setting of astronaut radiation-related risk limits will ultimately be decided by the Space Agencies. Suggestions are provided for further work which builds on and extends this new HRA approach, e.g., by eventually including non-cancer effects and detailed space dosimetry.
Collapse
Affiliation(s)
- Linda Walsh
- Department of Physics, Science Faculty, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Luana Hafner
- Department of Physics, ETH Zurich, Otto-Stern-Weg 1, 8092 Zurich, Switzerland
| | - Ulrich Straube
- Medical Operations and Space Medicine, HRE-OM, European Space Agency, ESA, European Astronaut Centre, EAC, Cologne, Germany
| | - Alexander Ulanowski
- Present Address: Environment Laboratories, International Atomic Energy Agency, 2444 Seibersdorf, Austria
- Institute of Radiation Medicine, Helmholtz Zentrum München- German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Anna Fogtman
- Medical Operations and Space Medicine, HRE-OM, European Space Agency, ESA, European Astronaut Centre, EAC, Cologne, Germany
| | - Marco Durante
- Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
| | - Guillaume Weerts
- Medical Operations and Space Medicine, HRE-OM, European Space Agency, ESA, European Astronaut Centre, EAC, Cologne, Germany
| | - Uwe Schneider
- Department of Physics, Science Faculty, University of Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Radiotherapy Hirslanden, Witellikerstrasse 40, 8032 Zurich, Switzerland
| |
Collapse
|
17
|
Folkers C. Disproportionate Impacts of Radiation Exposure on Women, Children, and Pregnancy: Taking Back our Narrative. JOURNAL OF THE HISTORY OF BIOLOGY 2021; 54:31-66. [PMID: 33788123 DOI: 10.1007/s10739-021-09630-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Narratives surrounding ionizing radiation have often minimized radioactivity's impact on the health of human and non-human animals and the natural environment. Many Cold War research policies, practices, and interpretations drove nuclear technology forward by institutionally obscuring empirical evidence of radiation's disproportionate and low-dose harm-a legacy we still confront. Women, children, and pregnancy development are particularly sensitive to exposure from radioactivity, suffering more damage per dose than adult males, even down to small doses, making low doses a cornerstone of concern. Evidence of compounding generational damage could indicate increased sensitivity through heritable impact. This essay examines the existing empirical evidence demonstrating these sensitivities, and how research institutions and regulatory authorities have devalued them, willingly sacrificing health in the service of maintaining and expanding nuclear technology (Nadesan 2019). Radiation's disproportionate impacts should now be the research and policy focus, as society is poised to make crucial and long-lasting decisions regarding climate change mitigation and future energy sources (Brown 2019b).
Collapse
Affiliation(s)
- Cynthia Folkers
- Beyond Nuclear, 7304 Carroll Ave #182, Takoma Park, MD, 20912, USA.
| |
Collapse
|
18
|
Tsuchiya H, Shimada M, Tsukada K, Meng Q, Kobayashi J, Matsumoto Y. Diminished or inversed dose-rate effect on clonogenic ability in Ku-deficient rodent cells. JOURNAL OF RADIATION RESEARCH 2021; 62:198-205. [PMID: 33372229 PMCID: PMC7948855 DOI: 10.1093/jrr/rraa128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 11/09/2020] [Indexed: 06/12/2023]
Abstract
The biological effects of ionizing radiation, especially those of sparsely ionizing radiations like X-ray and γ-ray, are generally reduced as the dose rate is reduced. This phenomenon is known as 'the dose-rate effect'. The dose-rate effect is considered to be due to the repair of DNA damage during irradiation but the precise mechanisms for the dose-rate effect remain to be clarified. Ku70, Ku86 and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are thought to comprise the sensor for DNA double-strand break (DSB) repair through non-homologous end joining (NHEJ). In this study, we measured the clonogenic ability of Ku70-, Ku86- or DNA-PKcs-deficient rodent cells, in parallel with respective control cells, in response to high dose-rate (HDR) and low dose-rate (LDR) γ-ray radiation (~0.9 and ~1 mGy/min, respectively). Control cells and murine embryonic fibroblasts (MEF) from a severe combined immunodeficiency (scid) mouse, which is DNA-PKcs-deficient, showed higher cell survival after LDR irradiation than after HDR irradiation at the same dose. On the other hand, MEF from Ku70-/- mice exhibited lower clonogenic cell survival after LDR irradiation than after HDR irradiation. XR-V15B and xrs-5 cells, which are Ku86-deficient, exhibited mostly identical clonogenic cell survival after LDR and HDR irradiation. Thus, the dose-rate effect in terms of clonogenic cell survival is diminished or even inversed in Ku-deficient rodent cells. These observations indicate the involvement of Ku in the dose-rate effect.
Collapse
Affiliation(s)
- Hisayo Tsuchiya
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| | - Mikio Shimada
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| | - Kaima Tsukada
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| | - Qingmei Meng
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto 606-8501 Japan
| | - Junya Kobayashi
- Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyo-ku, Kyoto 606-8501 Japan
| | - Yoshihisa Matsumoto
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 Japan
| |
Collapse
|
19
|
Stouten S, Verduyn Lunel S, Finnon R, Badie C, Dekkers F. Modeling low-dose radiation-induced acute myeloid leukemia in male CBA/H mice. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:49-60. [PMID: 33221961 PMCID: PMC7902600 DOI: 10.1007/s00411-020-00880-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/01/2020] [Indexed: 06/11/2023]
Abstract
The effect of low-dose ionizing radiation exposure on leukemia incidence remains poorly understood. Possible dose-response curves for various forms of leukemia are largely based on cohorts of atomic bomb survivors. Animal studies can contribute to an improved understanding of radiation-induced acute myeloid leukemia (rAML) in humans. In male CBA/H mice, incidence of rAML can be described by a two-hit model involving a radiation-induced deletion with Sfpi1 gene copy loss and a point mutation in the remaining Sfpi1 allele. In the present study (historical) mouse data were used and these processes were translated into a mathematical model to study photon-induced low-dose AML incidence in male CBA/H mice following acute exposure. Numerical model solutions for low-dose rAML incidence and diagnosis times could respectively be approximated with a model linear-quadratic in radiation dose and a normal cumulative distribution function. Interestingly, the low-dose incidence was found to be proportional to the modeled number of cells carrying the Sfpi1 deletion present per mouse following exposure. After making only model-derived high-dose rAML estimates available to extrapolate from, the linear-quadratic model could be used to approximate low-dose rAML incidence calculated with our mouse model. The accuracy in estimating low-dose rAML incidence when extrapolating from a linear model using a low-dose effectiveness factor was found to depend on whether a data transformation was used in the curve fitting procedure.
Collapse
Affiliation(s)
- Sjors Stouten
- Netherlands National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
- Mathematical Institute, Utrecht University, Utrecht, 3508 TA, The Netherlands.
| | | | - Rosemary Finnon
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Didcot, OX11 ORQ, UK
| | - Christophe Badie
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Didcot, OX11 ORQ, UK
| | - Fieke Dekkers
- Netherlands National Institute for Public Health and the Environment, Bilthoven, The Netherlands
- Mathematical Institute, Utrecht University, Utrecht, 3508 TA, The Netherlands
| |
Collapse
|
20
|
Leuraud K, Richardson DB, Cardis E, Daniels RD, Gillies M, Haylock R, Moissonnier M, Schubauer-Berigan MK, Thierry-Chef I, Kesminiene A, Laurier D. Risk of cancer associated with low-dose radiation exposure: comparison of results between the INWORKS nuclear workers study and the A-bomb survivors study. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:23-39. [PMID: 33479781 PMCID: PMC7902587 DOI: 10.1007/s00411-020-00890-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/19/2020] [Indexed: 05/21/2023]
Abstract
The Life Span Study (LSS) of Japanese atomic bomb survivors has served as the primary basis for estimates of radiation-related disease risks that inform radiation protection standards. The long-term follow-up of radiation-monitored nuclear workers provides estimates of radiation-cancer associations that complement findings from the LSS. Here, a comparison of radiation-cancer mortality risk estimates derived from the LSS and INWORKS, a large international nuclear worker study, is presented. Restrictions were made, so that the two study populations were similar with respect to ages and periods of exposure, leading to selection of 45,625 A-bomb survivors and 259,350 nuclear workers. For solid cancer, excess relative rates (ERR) per gray (Gy) were 0.28 (90% CI 0.18; 0.38) in the LSS, and 0.29 (90% CI 0.07; 0.53) in INWORKS. A joint analysis of the data allowed for a formal assessment of heterogeneity of the ERR per Gy across the two studies (P = 0.909), with minimal evidence of curvature or of a modifying effect of attained age, age at exposure, or sex in either study. There was evidence in both cohorts of modification of the excess absolute risk (EAR) of solid cancer by attained age, with a trend of increasing EAR per Gy with attained age. For leukemia, under a simple linear model, the ERR per Gy was 2.75 (90% CI 1.73; 4.21) in the LSS and 3.15 (90% CI 1.12; 5.72) in INWORKS, with evidence of curvature in the association across the range of dose observed in the LSS but not in INWORKS; the EAR per Gy was 3.54 (90% CI 2.30; 5.05) in the LSS and 2.03 (90% CI 0.36; 4.07) in INWORKS. These findings from different study populations may help understanding of radiation risks, with INWORKS contributing information derived from cohorts of workers with protracted low dose-rate exposures.
Collapse
Affiliation(s)
- Klervi Leuraud
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France.
| | - David B Richardson
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA
| | - Elisabeth Cardis
- Center for Research in Environmental Epidemiology, Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Robert D Daniels
- National Institute for Occupational Safety and Health (NIOSH), Cincinnati, OH, USA
| | - Michael Gillies
- Public Health England Centre for Radiation, Chemical and Environmental Hazards (PHE-CRCE), Chilton, UK
| | - Richard Haylock
- Public Health England Centre for Radiation, Chemical and Environmental Hazards (PHE-CRCE), Chilton, UK
| | | | | | - Isabelle Thierry-Chef
- Center for Research in Environmental Epidemiology, Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | - Dominique Laurier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France
| |
Collapse
|
21
|
Harrison JD, Balonov M, Bochud F, Martin C, Menzel HG, Ortiz-Lopez P, Smith-Bindman R, Simmonds JR, Wakeford R. ICRP Publication 147: Use of Dose Quantities in Radiological Protection. Ann ICRP 2021; 50:9-82. [PMID: 33653178 DOI: 10.1177/0146645320911864] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
22
|
Fernando C, Byun SH, Shi X, Seymour CB, Mothersill CE. Isolation of the effects of alpha-related components from total effects of radium at low doses. Int J Radiat Biol 2021; 98:1168-1175. [PMID: 33332185 DOI: 10.1080/09553002.2020.1866226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE Radium is the most common source of alpha radiation exposure to humans and non-human species in the environment but the dosimetry is complicated by the decay chain which involves gamma exposure due to radon daughters. This paper seeks to determine the separate contributions of alpha and gamma doses to the total dose and total direct and non-targeted effect in a fish and a human cell line. MATERIALS AND METHODS This study aimed to isolate the effect of alpha particles following exposure to low doses of radium in cells, and their progeny which received no further exposure. This was initially done by comparing the survival values of a human keratinocyte cell line (HaCaT) and an embryonic Chinook salmon cell line (CHSE-214) exposed to gamma radiation, from survival of the same cell lines exposed to mixed alpha and gamma radiation through exposure to Ra-226 and its decay products. A Monte Carlo simulation was later performed to determine the contributions of radium decay products including radon daughters. RESULTS The human cell line showed increased radioresistance when exposed to low doses of alpha particles. In contrast the fish cell line, which demonstrated radioresistance to low dose gamma radiation, showed increased lethality when exposed to low doses of alpha particles. Significant and complex levels of non-targeted effects were induced in progeny of irradiated cells. The simulation showed that gamma and beta decay products did not contribute significant dose and the highest beta dose was below the threshold for inducing non-targeted effects. CONCLUSIONS The results confirm the need to consider the dose-response relationship when developing radiation weighting factors for low dose exposures, as well as the need to be aware of possible cell line and species differences.
Collapse
Affiliation(s)
- Chandula Fernando
- Radiation Sciences Graduate Program, McMaster University, Hamilton, Canada
| | - Soo Hyun Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, Canada
| | - Xiaopei Shi
- Department of Biology, McMaster University, Hamilton, Canada
| | - Colin B Seymour
- Department of Biology, McMaster University, Hamilton, Canada
| | | |
Collapse
|
23
|
Bando M, Tsunoyama Y, Suzuki K, Toki H. WAM to SeeSaw model for cancer therapy - overcoming LQM difficulties. Int J Radiat Biol 2020; 97:228-239. [PMID: 33253050 DOI: 10.1080/09553002.2021.1854487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE The assessment of biological effects caused by radiation exposure has been currently carried out with the linear-quadratic (LQ) model as an extension of the linear non-threshold (LNT) model. In this study, we suggest a new mathematical model named as SeaSaw (SS) model, which describes proliferation and cell death effects by taking account of Bergonie-Tribondeau's law in terms of a differential equation in time. We show how this model overcomes the long-standing difficulties of the LQ model. MATERIALS AND METHODS We construct the SS model as an extended Wack-A-Mole (WAM) model by using a differential equation with respect to time in order to express the dynamics of the proliferation effect. A large number of accumulated data of such parameters as α and β in the LQ based models provide us with valuable pieces of information on the corresponding parameter b 1 and the maximum volume V m of the SS model. The dose rate b 1 and the notion of active cell can explain the present data without introduction of β, which is obtained by comparing the SS model with not only the cancer therapy data but also with in vitro experimental data. Numerical calculations are presented to grasp the global features of the SS model. RESULTS The SS model predicts the time dependence of the number of active- and inactive-cells. The SS model clarifies how the effect of radiation depends on the cancer stage at the starting time in the treatment. Further, the time dependence of the tumor volume is calculated by changing individual dose strength, which results in the change of the irradiation duration for the same effect. We can consider continuous irradiation in the SS model with interesting outcome on the time dependence of the tumor volume for various dose rates. Especially by choosing the value of the dose rate to be balanced with the total growth rate, the tumor volume is kept constant. CONCLUSIONS The SS model gives a simple equation to study the situation of clinical radiation therapy and risk estimation of radiation. The radiation parameter extracted from the cancer therapy is close to the value obtained from animal experiment in vitro and in vivo. We expect the SS model leads us to a unified description of radiation therapy and protection and provides a great development in cancer-therapy clinical-planning.
Collapse
Affiliation(s)
- Masako Bando
- Research Center for Nuclear Physics, Osaka University, Osaka, Japan
| | - Yuichi Tsunoyama
- Radioisotope Research Center, Agency for Health, Safety and Environment, Kyoto University, Kyoto, Japan
| | - Kazuyo Suzuki
- Preemptive Medicine and Lifestyle-Related Disease Research Center, Kyoto University Hospital, Kyoto University, Kyoto, Japan
| | - Hiroshi Toki
- Research Center for Nuclear Physics, Osaka University, Osaka, Japan
| |
Collapse
|
24
|
Doi K, Kai M, Suzuki K, Imaoka T, Sasatani M, Tanaka S, Yamada Y, Kakinuma S. Estimation of Dose-Rate Effectiveness Factor for Malignant Tumor Mortality: Joint Analysis of Mouse Data Exposed to Chronic and Acute Radiation. Radiat Res 2020; 194:500-510. [DOI: 10.1667/rade-19-00003.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 08/06/2020] [Indexed: 11/03/2022]
Affiliation(s)
| | - Michiaki Kai
- Environmental Health Science Division, Oita University of Nursing and Health Sciences, Oita, Japan
| | - Keiji Suzuki
- Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | | | - Megumi Sasatani
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Satoshi Tanaka
- Department of Radiobiology, Institute for Environmental Sciences, Aomori, Japan
| | - Yutaka Yamada
- Department of Radioecology and Fukushima Project, Center for Advanced Radiation Emergency Medicine, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | | |
Collapse
|
25
|
Llurda-Almuzara L, Olaya Lubián R, Pérez De Gracia D, Pérez-Bellmunt A, Schroderus-Salo T, Tomás Sábado J. Spanish translation and psychometric evaluation of the Healthcare Professional Knowledge of Radiation Protection scale. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2020; 40:740-752. [PMID: 32311683 DOI: 10.1088/1361-6498/ab8b34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The objective of this work was to make an intercultural adaptation and provide a Spanish translation and psychometric evaluation of the original English version of the Healthcare Professional Knowledge of Radiation Protection (HPKRP) scale. The Spanish translation was carried out following international guidelines for the process of cross-cultural adaptation of self-report measures. A cross-sectional design study was carried out. One hundred and thirty-eight nurses from four different hospitals in Barcelona (Spain) completed the Spanish version of the scale. The total score of the scale was calculated. The Pearson correlation coefficient (PCC) was used to evaluate a possible correlation between score and years of experience. A t-test for independent samples was used to evaluate significant differences between different groups. Cronbach's alpha, the corrected item-total correlation coefficient and the test-retest coefficient were used to determine internal consistency. The exploratory factor and parallel analysis were also calculated. All statistical tests were carried out with a level of significance α = 0.05. The mean scale score was poor among Spanish nurses. The PCC between total score and years of experience showed a non-significant correlation (p > 0.05). No differences were found between nurses who worked in radiation-exposed units and those who worked in units without radiation exposure (p > 0.05). A Cronbach α of 0.98 was obtained for the items of the scale. The corrected item-total correlation range was 0.5-0.8. The test-retest correlation coefficient was 0.9. The exploratory analysis factor showed a single factorial structure which explained 60.86% of the variance. The new scale translated into Spanish (Sp-HPKRP) could be used to evaluate the degree of knowledge about radiological protection.
Collapse
Affiliation(s)
- Luis Llurda-Almuzara
- Área de Estructura y Función del Cuerpo Humano, Unidad de Anatomía, Universitat Internacional de Catalunya, Sant Cugat, Spain. Facultat de Medicina i Ciències de la Salut Universitat Internacional de Catalunya C/ Josep Trueta s/n 08195 Sant Cugat del Vallès, Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
26
|
Zander A, Paunesku T, Woloschak GE. Analyses of cancer incidence and other morbidities in gamma irradiated B6CF1 mice. PLoS One 2020; 15:e0231510. [PMID: 32818954 PMCID: PMC7440931 DOI: 10.1371/journal.pone.0231510] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
Abstract
With increasing medical radiation exposures, it is important to understand how different modes of delivery of ionizing radiation as well as total doses of exposure impact health outcomes. Our lab studied the risks associated with ionizing radiation by analyzing the Northwestern University Radiation Archive for animals (NURA). NURA contains detailed data from a series of 10 individual neutron and gamma irradiation experiments conducted on over 50,000 mice. Rigorous statistical testing on control mice from all Janus experiments enabled us to select studies that could be compared to one another and uncover unexpected differences among the controls as well as experimental animals. For controls, mice sham irradiated with 300 fractions died significantly earlier than those with fewer sham fractions and were excluded from the pooled dataset. Using the integrated dataset of gamma irradiated and control mice, we found that fractionation significantly decreased the death hazard for animals dying of lymphomas, tumors, non-tumors, and unknown causes. Gender differences in frequencies of causes of death were identified irrespective of irradiation and dose fractionation, with female mice being at a greater risk for all causes of death, except for lung tumors. Irradiated and control male mice were at a significantly greater risk for lung tumors, the opposite from observations noted in humans. Additionally, we discovered that lymphoma deaths can occur quickly after exposures to high doses of gamma rays. This study systematically cross-compared outcomes of different modes of fractionation evaluated across different Janus experiments and across a wide span of total doses. It demonstrates that protraction modulated survival and disease status differently based on the total dose, cause of death, and sex of an animal. This novel method for analyzing the Janus datasets will lead to insightful new mechanistic hypotheses and research in the fields of radiation biology and protection.
Collapse
Affiliation(s)
- Alia Zander
- Feinberg School of Medicine, Radiation Oncology, Northwestern University, Chicago, IL, United States of America
| | - Tatjana Paunesku
- Feinberg School of Medicine, Radiation Oncology, Northwestern University, Chicago, IL, United States of America
| | - Gayle E. Woloschak
- Feinberg School of Medicine, Radiation Oncology, Northwestern University, Chicago, IL, United States of America
- * E-mail:
| |
Collapse
|
27
|
Olofsson D, Cheng L, Fernández RB, Płódowska M, Riego ML, Akuwudike P, Lisowska H, Lundholm L, Wojcik A. Biological effectiveness of very high gamma dose rate and its implication for radiological protection. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2020; 59:451-460. [PMID: 32488310 PMCID: PMC7368856 DOI: 10.1007/s00411-020-00852-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 05/25/2020] [Indexed: 05/06/2023]
Abstract
Many experimental studies are carried out to compare biological effectiveness of high dose rate (HDR) with that of low dose rate (LDR). The rational for this is the uncertainty regarding the value of the dose rate effectiveness factor (DREF) used in radiological protection. While a LDR is defined as 0.1 mGy/min or lower, anything above that is seen as HDR. In cell and animal experiments, a dose rate around 1 Gy/min is usually used as representative for HDR. However, atomic bomb survivors, the reference cohort for radiological protection, were exposed to tens of Gy/min. The important question is whether gamma radiation delivered at very high dose rate (VHDR-several Gy/min) is more effective in inducing DNA damage than that delivered at HDR. The aim of this investigation was to compare the biological effectiveness of gamma radiation delivered at VHDR (8.25 Gy/min) with that of HDR (0.38 Gy/min or 0.79 Gy/min). Experiments were carried out with human peripheral mononuclear cells (PBMC) and the human osteosarcoma cell line U2OS. Endpoints related to DNA damage response were analysed. The results show that in PBMC, VHDR is more effective than HDR in inducing gene expression and micronuclei. In U2OS cells, the repair of 53BP1 foci was delayed after VHDR indicating a higher level of damage complexity, but no VHDR effect was observed at the level of micronuclei and clonogenic cell survival. We suggest that the DREF value may be underestimated when the biological effectiveness of HDR and LDR is compared.
Collapse
Affiliation(s)
- Dante Olofsson
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden
| | - Lei Cheng
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden
| | - Rubén Barrios Fernández
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden
| | - Magdalena Płódowska
- Department of Radiobiology and Immunology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Milagrosa López Riego
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden
| | - Pamela Akuwudike
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden
| | - Halina Lisowska
- Department of Radiobiology and Immunology, Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Lovisa Lundholm
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden
| | - Andrzej Wojcik
- Department of Molecular Biosciences, Centre for Radiation Protection Research, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91, Stockholm, Sweden.
- Department of Radiobiology and Immunology, Institute of Biology, Jan Kochanowski University, Kielce, Poland.
| |
Collapse
|
28
|
Helm JS, Rudel RA. Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast. Arch Toxicol 2020. [PMID: 32399610 DOI: 10.1007/s00204-020-02752-z)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.
Collapse
Affiliation(s)
- Jessica S Helm
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA
| | - Ruthann A Rudel
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA.
| |
Collapse
|
29
|
Helm JS, Rudel RA. Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast. Arch Toxicol 2020; 94:1511-1549. [PMID: 32399610 PMCID: PMC7261741 DOI: 10.1007/s00204-020-02752-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022]
Abstract
Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.
Collapse
Affiliation(s)
- Jessica S Helm
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA
| | - Ruthann A Rudel
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA.
| |
Collapse
|
30
|
Rühm W, Breckow J, Dietze G, Friedl A, Greinert R, Jacob P, Kistinger S, Michel R, Müller WU, Otten H, Streffer C, Weiss W. Dose limits for occupational exposure to ionising radiation and genotoxic carcinogens: a German perspective. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2020; 59:9-27. [PMID: 31677018 DOI: 10.1007/s00411-019-00817-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
This paper summarises the view of the German Commission on Radiological Protection ("Strahlenschutzkommission", SSK) on the rationale behind the currently valid dose limits and dose constraints for workers recommended by the International Commission on Radiological Protection (ICRP). The paper includes a discussion of the reasoning behind current dose limits followed by a discussion of the detriment used by ICRP as a measure for stochastic health effects. Studies on radiation-induced cancer are reviewed because this endpoint represents the most important contribution to detriment. Recent findings on radiation-induced circulatory disease that are currently not included in detriment calculation are also reviewed. It appeared that for detriment calculations the contribution of circulatory diseases plays only a secondary role, although the uncertainties involved in their risk estimates are considerable. These discussions are complemented by a review of the procedures currently in use in Germany, or in discussion elsewhere, to define limits for genotoxic carcinogens. To put these concepts in perspective, actual occupational radiation exposures are exemplified with data from Germany, for the year 2012, and regulations in Germany are compared to the recommendations issued by ICRP. Conclusions include, among others, considerations on radiation protection concepts currently in use and recommendations of the SSK on the limitation of annual effective dose and effective dose cumulated over a whole working life.
Collapse
Affiliation(s)
- Werner Rühm
- Helmholtz Zentrum München, Institute of Radiation Therapy, Ingolstädter Landstr. 1, 85764, Oberschleißheim, Germany.
| | | | - Günter Dietze
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Anna Friedl
- Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany
| | | | - Peter Jacob
- Helmholtz Zentrum München, Neuherberg, Germany
| | | | | | | | - Heinz Otten
- Deutsche Gesetzliche Unfallversicherung, Berlin, Germany
| | | | | |
Collapse
|
31
|
Walsh L, Schneider U. Effect of Heterogeneity in Background Incidence on Inference about the Solid-Cancer Radiation Dose Response in Atomic Bomb Survivors by Cologne et al., Radiat Res 2019; 192:388–398. Radiat Res 2020; 193:195-197. [DOI: 10.1667/rrlte7.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Linda Walsh
- Department of Physics, Science Faculty, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Uwe Schneider
- Department of Physics, Science Faculty, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| |
Collapse
|
32
|
Zhang W, Laurier D, Cléro E, Hamada N, Preston D, Vaillant L, Ban N. Sensitivity analysis of parameters and methodological choices used in calculation of radiation detriment for solid cancer. Int J Radiat Biol 2020; 96:596-605. [PMID: 31914349 DOI: 10.1080/09553002.2020.1708499] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Purpose: Radiation detriment is a concept used by the International Commission on Radiological Protection (ICRP) to quantify the harmful health effects of radiation exposure in humans. The current approach of radiation detriment calculation has been defined in ICRP Publication 103 in 2007. It is determined from lifetime risk of cancer and heritable effects for a composite reference population, taking into account the severity of the disease in terms of lethality, quality of life and years of life lost. Many parameters are used in the calculations and the variation of these parameters can have effects on the cancer detriment, which needs to be investigated.Materials and methods: In this paper, we conducted a sensitivity analysis for examining the impact of 12 different parameters or methodological choices on the calculation of solid cancer detriment, such as the lifetime risk calculation method, survival curve, dose and dose-rate effectiveness factor (DDREF), age-at-exposure, sex, reference population, risk transfer model, latency, attained age, lethality, minimum quality of life factor and relative cancer-free life lost. Sensitivity calculations have been performed systematically for each of 10 solid cancer sites, by changing each one of the parameters in turn.Results: This sensitivity analysis demonstrated a large impact on estimated detriment from DDREF, age-at-exposure, sex and lethality, a noticeable impact of risk transfer model associated to variation of baseline rates, and a limited impact of risk calculation method, survival curve, latency, attained age, quality of life and relative years of life lost.Conclusion: These results could have implications for radiation protection standards, and they should help define priorities for future research in the field of low radiation dose and dose rate research. The present sensitivity analysis is part of a global effort of ICRP to review the bases of radiation detriment calculation and assess potential evolutions to improve the radiation protection system.
Collapse
Affiliation(s)
- Wei Zhang
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Oxon, UK
| | - Dominique Laurier
- Health and Environmental Division, Institute for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses, France
| | - Enora Cléro
- Health and Environmental Division, Institute for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses, France
| | - Nobuyuki Hamada
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan
| | - Dale Preston
- Hirosoft International Corporation, Eureka, CA, USA
| | - Ludovic Vaillant
- Centre d'etude sur l'Evaluation de la Protection dans le domaine Nucleaire (CEPN), Fontenay-aux-Roses, France
| | | |
Collapse
|
33
|
The Impact of Dose Rate on DNA Double-Strand Break Formation and Repair in Human Lymphocytes Exposed to Fast Neutron Irradiation. Int J Mol Sci 2019; 20:ijms20215350. [PMID: 31661782 PMCID: PMC6862539 DOI: 10.3390/ijms20215350] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/16/2019] [Accepted: 10/19/2019] [Indexed: 12/12/2022] Open
Abstract
The lack of information on how biological systems respond to low-dose and low dose-rate exposures makes it difficult to accurately assess the carcinogenic risks. This is of critical importance to space radiation, which remains a serious concern for long-term manned space exploration. In this study, the γ-H2AX foci assay was used to follow DNA double-strand break (DSB) induction and repair following exposure to neutron irradiation, which is produced as secondary radiation in the space environment. Human lymphocytes were exposed to high dose-rate (HDR: 0.400 Gy/min) and low dose-rate (LDR: 0.015 Gy/min) p(66)/Be(40) neutrons. DNA DSB induction was investigated 30 min post exposure to neutron doses ranging from 0.125 to 2 Gy. Repair kinetics was studied at different time points after a 1 Gy neutron dose. Our results indicated that γ-H2AX foci formation was 40% higher at HDR exposure compared to LDR exposure. The maximum γ-H2AX foci levels decreased gradually to 1.65 ± 0.64 foci/cell (LDR) and 1.29 ± 0.45 (HDR) at 24 h postirradiation, remaining significantly higher than background levels. This illustrates a significant effect of dose rate on neutron-induced DNA damage. While no significant difference was observed in residual DNA damage after 24 h, the DSB repair half-life of LDR exposure was slower than that of HDR exposure. The results give a first indication that the dose rate should be taken into account for cancer risk estimations related to neutrons.
Collapse
|
34
|
Cléro E, Vaillant L, Hamada N, Zhang W, Preston D, Laurier D, Ban N. History of radiation detriment and its calculation methodology used in ICRP Publication 103. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2019; 39:R19-R36. [PMID: 31189142 DOI: 10.1088/1361-6498/ab294a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Over the past decades, the International Commission on Radiological Protection (ICRP) has used radiation detriment, which is a multidimensional concept to quantify the overall harm to health from stochastic effects of low-level radiation exposure of different parts of the body. Each tissue-specific detriment is determined from the nominal tissue-specific risk coefficient, weighted by the severity of the disease in terms of lethality, impact on quality of life and years of life lost. Total detriment is the sum of the detriments for separate tissues and organs. Tissue weighting factors for the calculation of effective dose are based on relative contributions of each tissue to the total detriment. Calculating radiation detriment is a complex process that requires information from various sources and judgements on how to achieve calculations. As such, it is important to document its calculation methodology. To improve the traceability of calculations and form a solid basis for future recommendations, the ICRP Task Group 102 on detriment calculation methodology was established in 2016. As part of its mission, the history of radiation detriment was reviewed, and the process of detriment calculation was detailed. This article summarises that work, aiming to clarify the methodology of detriment calculation currently used by ICRP.
Collapse
Affiliation(s)
- Enora Cléro
- Institute for Radiological Protection and Nuclear Safety, Health and Environment Division, Fontenay-aux-Roses, France
| | | | | | | | | | | | | |
Collapse
|
35
|
Matsuya Y, McMahon SJ, Ghita M, Yoshii Y, Sato T, Date H, Prise KM. Intensity Modulated Radiation Fields Induce Protective Effects and Reduce Importance of Dose-Rate Effects. Sci Rep 2019; 9:9483. [PMID: 31263149 PMCID: PMC6603191 DOI: 10.1038/s41598-019-45960-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/19/2019] [Indexed: 11/09/2022] Open
Abstract
In advanced radiotherapy, intensity modulated radiation fields and complex dose-delivery are utilized to prescribe higher doses to tumours. Here, we investigated the impact of modulated radiation fields on radio-sensitivity and cell recovery during dose delivery. We generated experimental survival data after single-dose, split-dose and fractionated irradiation in normal human skin fibroblast cells (AGO1522) and human prostate cancer cells (DU145). The dose was delivered to either 50% of the area of a T25 flask containing the cells (half-field) or 100% of the flask (uniform-field). We also modelled the impact of dose-rate effects and intercellular signalling on cell-killing. Applying the model to the survival data, it is found that (i) in-field cell survival under half-field exposure is higher than uniform-field exposure for the same delivered dose; (ii) the importance of sub-lethal damage repair (SLDR) in AGO1522 cells is reduced under half-field exposure; (iii) the yield of initial DNA lesions measured with half-field exposure is smaller than that with uniform-field exposure. These results suggest that increased cell survival under half-field exposure is predominantly attributed not to rescue effects (increased SLDR) but protective effects (reduced induction of initial DNA lesions). In support of these protective effects, the reduced DNA damage leads to modulation of cell-cycle dynamics, i.e., less G1 arrest 6 h after irradiation. These findings provide a new understanding of the impact of dose-rate effects and protective effects measured after modulated field irradiation.
Collapse
Affiliation(s)
- Yusuke Matsuya
- Japan Atomic Energy Agency (JAEA), Nuclear Science and Engineering Center, Research Group for Radiation Transport Analysis, 2-4 Shirakata, Tokai, 319-1195, Ibaraki, Japan. .,Graduate School of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, 060-0812, Hokkaido, Japan.
| | - Stephen J McMahon
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, BT7 9AE, Belfast, UK
| | - Mihaela Ghita
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, BT7 9AE, Belfast, UK
| | - Yuji Yoshii
- Biological Research, Education and Instrumentation Center, Sapporo Medical University, Minami-1 Nishi-17, Chuo-ku, Sapporo, 060-8556, Hokkaido, Japan
| | - Tatsuhiko Sato
- Japan Atomic Energy Agency (JAEA), Nuclear Science and Engineering Center, Research Group for Radiation Transport Analysis, 2-4 Shirakata, Tokai, 319-1195, Ibaraki, Japan
| | - Hiroyuki Date
- Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, 060-0812, Hokkaido, Japan
| | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, BT7 9AE, Belfast, UK
| |
Collapse
|
36
|
Kocher DC, Apostoaei AI, Hoffman FO. Response to González. HEALTH PHYSICS 2019; 116:831. [PMID: 31021948 DOI: 10.1097/hp.0000000000001086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- David C Kocher
- Oak Ridge Center for Risk Analysis. Inc. 102 Donner Drive Oak Ridge, TN 37830
| | | | | |
Collapse
|
37
|
Rehani MM. Looking for solutions: vision and a call-for-attention for radiation research scientists. Int J Radiat Biol 2019; 95:793-796. [PMID: 30652955 DOI: 10.1080/09553002.2019.1569775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Purpose: The concept of benefit-risk assessment has often been propagated for clinical professionals for deciding the radiological exam for the patient. A detailed look into how to use this concept leads to several unanswered questions. The purpose of this article is to bring forth questions which have remained unanswered for several decades. These questions pertain to our inability to provide needed information to physicians for making benefit-risk assessment for deciding a frequent imaging modality like the computed tomography (CT) such as non-applicability of risk estimates to an individual patient, the concept of cumulative risk at low doses, accounting for the time gap between series of CT scans, risk variation with age, gender and disease condition. In the absence of concrete information on these, it becomes essentially benefit assessment rather than benefit-risk. The article also provides a motivation to think that there are a large number of patients getting exposed every year to radiation doses over 100 mSv of effective dose and several tens of mGy of organ doses. This may provide a very large cohort for radiation effect studies. Further, a series of ideas are presented as a vision for future studies. Conclusions: The article emphasizes the need to create a research agenda to deal with day-to-day questions faced in medical practice and provides a call-for-attention. Further, it provides some challenging ideas as outside of the box thinking points that may provide research direction for future years.
Collapse
|
38
|
Shore RE, Beck HL, Boice JD, Caffrey EA, Davis S, Grogan HA, Mettler FA, Preston RJ, Till JE, Wakeford R, Walsh L, Dauer LT. Recent Epidemiologic Studies and the Linear No-Threshold Model For Radiation Protection-Considerations Regarding NCRP Commentary 27. HEALTH PHYSICS 2019; 116:235-246. [PMID: 30585971 DOI: 10.1097/hp.0000000000001015] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
National Council on Radiation Protection and Measurements Commentary 27 examines recent epidemiologic data primarily from low-dose or low dose-rate studies of low linear-energy-transfer radiation and cancer to assess whether they support the linear no-threshold model as used in radiation protection. The commentary provides a critical review of low-dose or low dose-rate studies, most published within the last 10 y, that are applicable to current occupational, environmental, and medical radiation exposures. The strengths and weaknesses of the epidemiologic methods, dosimetry assessments, and statistical modeling of 29 epidemiologic studies of total solid cancer, leukemia, breast cancer, and thyroid cancer, as well as heritable effects and a few nonmalignant conditions, were evaluated. An appraisal of the degree to which the low-dose or low dose-rate studies supported a linear no-threshold model for radiation protection or on the contrary, demonstrated sufficient evidence that the linear no-threshold model is inappropriate for the purposes of radiation protection was also included. The review found that many, though not all, studies of solid cancer supported the continued use of the linear no-threshold model in radiation protection. Evaluations of the principal studies of leukemia and low-dose or low dose-rate radiation exposure also lent support for the linear no-threshold model as used in protection. Ischemic heart disease, a major type of cardiovascular disease, was examined briefly, but the results of recent studies were considered too weak or inconsistent to allow firm conclusions regarding support of the linear no-threshold model. It is acknowledged that the possible risks from very low doses of low linear-energy-transfer radiation are small and uncertain and that it may never be possible to prove or disprove the validity of the linear no-threshold assumption by epidemiologic means. Nonetheless, the preponderance of recent epidemiologic data on solid cancer is supportive of the continued use of the linear no-threshold model for the purposes of radiation protection. This conclusion is in accord with judgments by other national and international scientific committees, based on somewhat older data. Currently, no alternative dose-response relationship appears more pragmatic or prudent for radiation protection purposes than the linear no-threshold model.
Collapse
Affiliation(s)
- Roy E Shore
- New York University School of Medicine, New York, NY, and Radiation Effects Research Foundation, Hiroshima, Japan (retired)
| | | | - John D Boice
- National Council on Radiation Protection and Measurements, Bethesda, MD, and Vanderbilt University, Nashville, TN
| | | | - Scott Davis
- Fred Hutchinson Cancer Research Center, Seattle, WA
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Wilson‐Stewart K, Shanahan M, Fontanarosa D, Davidson R. Occupational radiation exposure to nursing staff during cardiovascular fluoroscopic procedures: A review of the literature. J Appl Clin Med Phys 2018; 19:282-297. [PMID: 30294978 PMCID: PMC6236819 DOI: 10.1002/acm2.12461] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/19/2018] [Accepted: 07/14/2018] [Indexed: 11/16/2022] Open
Abstract
Fluoroscopy is a method used to provide real time x-ray imaging of the body during medical procedures to assist with medical diagnosis and treatment. Recent technological advances have seen an increase in the number of fluoroscopic examinations being performed. Nurses are an integral part of the team conducting fluoroscopic investigations and are often located close to the patient resulting in an occupational exposure to radiation. The purpose of this review was to examine recent literature which investigates occupational exposure received by nursing staff during cardiovascular fluoroscopic procedures. Articles published between 2011 and 2017 have been searched and comprehensively reviewed on the referenced medical search engines. Twenty-four relevant studies were identified among which seventeen investigated nursing dose comparative to operator dose. Seven researched the effectiveness of interventions in reducing occupational exposure to nursing staff. While doctors remain at the highest risk of exposure during procedures, evidence suggests that nursing staff may be at risk of exceeding recommended dose limits in some circumstances. There is also evidence of inconsistent use of personal protection such as lead glasses and skull caps by nursing staff to minimize radiation exposure. Conclusions: The review has highlighted a lack of published literature focussing on dose to nurses. There is a need for future research in this area to inform nursing staff of factors which may contribute to high occupational doses and of methods for minimizing the risk of exposure, particularly regarding the importance of utilizing radiation protective equipment.
Collapse
Affiliation(s)
- Kelly Wilson‐Stewart
- School of Clinical SciencesQueensland University of TechnologyBrisbaneQldAustralia
- Cardiovascular SuitesGreenslopes Private HospitalBrisbaneQldAustralia
- Faculty of HealthUniversity of CanberraCanberraACTAustralia
| | | | - Davide Fontanarosa
- School of Clinical SciencesQueensland University of TechnologyBrisbaneQldAustralia
- Institute of Health and Biomedical InnovationQueensland University of TechnologyBrisbaneQldAustralia
| | - Rob Davidson
- Faculty of HealthUniversity of CanberraCanberraACTAustralia
| |
Collapse
|
40
|
Matsuya Y, McMahon SJ, Tsutsumi K, Sasaki K, Okuyama G, Yoshii Y, Mori R, Oikawa J, Prise KM, Date H. Investigation of dose-rate effects and cell-cycle distribution under protracted exposure to ionizing radiation for various dose-rates. Sci Rep 2018; 8:8287. [PMID: 29844494 PMCID: PMC5974424 DOI: 10.1038/s41598-018-26556-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/04/2018] [Indexed: 01/04/2023] Open
Abstract
During exposure to ionizing radiation, sub-lethal damage repair (SLDR) competes with DNA damage induction in cultured cells. By virtue of SLDR, cell survival increases with decrease of dose-rate, so-called dose-rate effects (DREs). Here, we focused on a wide dose-rate range and investigated the change of cell-cycle distribution during X-ray protracted exposure and dose-response curves via hybrid analysis with a combination of in vitro experiments and mathematical modelling. In the course of flow-cytometric cell-cycle analysis and clonogenic assays, we found the following responses in CHO-K1 cells: (1) The fraction of cells in S phase gradually increases during 6 h exposure at 3.0 Gy/h, which leads to radio-resistance. (2) Slight cell accumulation in S and G2/M phases is observed after exposure at 6.0 Gy/h for more than 10 hours. This suggests that an increase of SLDR rate for cells in S phase during irradiation may be a reproducible factor to describe changes in the dose-response curve at dose-rates of 3.0 and 6.0 Gy/h. By re-evaluating cell survival for various dose-rates of 0.186-60.0 Gy/h considering experimental-based DNA content and SLDR, it is suggested that the change of S phase fraction during irradiation modulates the dose-response curve and is possibly responsible for some inverse DREs.
Collapse
Affiliation(s)
- Yusuke Matsuya
- Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Stephen J McMahon
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, BT9 7AE, UK
| | - Kaori Tsutsumi
- Faculty of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Kohei Sasaki
- Faculty of Health Sciences, Hokkaido University of Science, Sapporo, 006-8585, Japan
| | - Go Okuyama
- Faculty of Health Sciences, Hokkaido University of Science, Sapporo, 006-8585, Japan
| | - Yuji Yoshii
- Biological Research, Education and Instrumentation Center, Sapporo Medical University, Sapporo, 060-8556, Japan
| | - Ryosuke Mori
- Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Joma Oikawa
- Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Kevin M Prise
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, BT9 7AE, UK
| | - Hiroyuki Date
- Faculty of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan.
| |
Collapse
|
41
|
Matsuya Y, McMahon SJ, Tsutsumi K, Sasaki K, Okuyama G, Yoshii Y, Mori R, Oikawa J, Prise KM, Date H. Investigation of dose-rate effects and cell-cycle distribution under protracted exposure to ionizing radiation for various dose-rates. Sci Rep 2018. [PMID: 29844494 DOI: 10.1038/s41598a018-26556a5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
During exposure to ionizing radiation, sub-lethal damage repair (SLDR) competes with DNA damage induction in cultured cells. By virtue of SLDR, cell survival increases with decrease of dose-rate, so-called dose-rate effects (DREs). Here, we focused on a wide dose-rate range and investigated the change of cell-cycle distribution during X-ray protracted exposure and dose-response curves via hybrid analysis with a combination of in vitro experiments and mathematical modelling. In the course of flow-cytometric cell-cycle analysis and clonogenic assays, we found the following responses in CHO-K1 cells: (1) The fraction of cells in S phase gradually increases during 6 h exposure at 3.0 Gy/h, which leads to radio-resistance. (2) Slight cell accumulation in S and G2/M phases is observed after exposure at 6.0 Gy/h for more than 10 hours. This suggests that an increase of SLDR rate for cells in S phase during irradiation may be a reproducible factor to describe changes in the dose-response curve at dose-rates of 3.0 and 6.0 Gy/h. By re-evaluating cell survival for various dose-rates of 0.186-60.0 Gy/h considering experimental-based DNA content and SLDR, it is suggested that the change of S phase fraction during irradiation modulates the dose-response curve and is possibly responsible for some inverse DREs.
Collapse
Affiliation(s)
- Yusuke Matsuya
- Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Stephen J McMahon
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, BT9 7AE, UK
| | - Kaori Tsutsumi
- Faculty of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Kohei Sasaki
- Faculty of Health Sciences, Hokkaido University of Science, Sapporo, 006-8585, Japan
| | - Go Okuyama
- Faculty of Health Sciences, Hokkaido University of Science, Sapporo, 006-8585, Japan
| | - Yuji Yoshii
- Biological Research, Education and Instrumentation Center, Sapporo Medical University, Sapporo, 060-8556, Japan
| | - Ryosuke Mori
- Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Joma Oikawa
- Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Kevin M Prise
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, BT9 7AE, UK
| | - Hiroyuki Date
- Faculty of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan.
| |
Collapse
|
42
|
Breckow J, Emami S, Amalhaf S, Beshgard A, Buermeyer J, Spruck K. Impact of updating the non-radiation parameters in the ICRP 103 detriment model. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2018; 57:89-98. [PMID: 29362875 PMCID: PMC5902532 DOI: 10.1007/s00411-018-0731-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/14/2018] [Indexed: 05/23/2023]
Abstract
The radiation detriment in ICRP 103 is defined as the product of the organ-specific risk coefficient and the damage that may be associated with a cancer type or hereditary effect. This is used to indicate a weighted risk according to the radiation sensitivity of different organs and the severity of damage that may possibly arise. While the risk refers to radiation exposure parameters, the extent of damage is independent of radiation. The parameters that are not affected by radiation are lethality, impairment of quality of life, and reduced life expectancy, which are considered as quantities associated with the severity of disease or damage. The damage and thus the detriment appear to be mostly affected by lethality, which is the quotient of the age-standardized mortality rate to the incidence rate. The analysis of the detriment presented in this paper focuses on the influence of the lethality on the detriment from 1980 to 2012 in the USA and Germany. While the lethality in this period covering more than three decades has decreased approximately linearly by 30% (both USA and Germany), within the same period the detriment declined only by 13% in the USA and by 15% in Germany. If only based on these two countries, an update on the detriment parameters with reference to 2007, when ICRP 103 was released, would result in a reduced weighted risk, i.e. the radiation detriment would be reduced by 10 to 15% from originally 5.7% per Sv for the whole population to roughly 5% per Sv.
Collapse
Affiliation(s)
- Joachim Breckow
- Institute of Medical Physics and Radiation Protection (IMPS), THM, University of Applied Sciences, Giessen, Germany.
| | - Samaneh Emami
- Institute of Medical Physics and Radiation Protection (IMPS), THM, University of Applied Sciences, Giessen, Germany
| | - Sara Amalhaf
- Institute of Medical Physics and Radiation Protection (IMPS), THM, University of Applied Sciences, Giessen, Germany
| | - Arwin Beshgard
- Institute of Medical Physics and Radiation Protection (IMPS), THM, University of Applied Sciences, Giessen, Germany
| | - Jonas Buermeyer
- Institute of Medical Physics and Radiation Protection (IMPS), THM, University of Applied Sciences, Giessen, Germany
| | - Kaija Spruck
- Institute of Medical Physics and Radiation Protection (IMPS), THM, University of Applied Sciences, Giessen, Germany
| |
Collapse
|
43
|
Abstract
The aim of the International Commission on Radiological Protection (ICRP) is to protect humans against cancer and other diseases and effects associated with exposure to ionising radiation, and also to protect the environment, without unduly limiting the beneficial use of ionising radiation. As of the second half of 2017, four committees are contributing to the overall mission of ICRP, including Committee 1 (Radiation Effects). The role of Committee 1 includes consideration of the risks and mechanisms of induction of cancer and heritable disease; discussion of the risks, severity, and mechanisms of induction of tissue/organ damage and developmental defects; and review of the effects of ionising radiation on non-human biota at population level. This paper gives an overview of the recent activities of Committee 1, and discusses the focus of its active task groups.
Collapse
Affiliation(s)
- W Rühm
- a Department of Radiation Sciences, Institute for Radiation Protection, Helmholtz Centre Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - N Ban
- b Nuclear Regulation Authority, Japan
| | | |
Collapse
|
44
|
Otsuka K, Suzuki K, Fujimichi Y, Tomita M, Iwasaki T. Cellular responses and gene expression profiles of colonic Lgr5+ stem cells after low-dose/low-dose-rate radiation exposure. JOURNAL OF RADIATION RESEARCH 2018; 59:ii18-ii22. [PMID: 29281035 PMCID: PMC5941159 DOI: 10.1093/jrr/rrx078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/13/2017] [Indexed: 06/07/2023]
Abstract
We previously found that high-dose-rate radiation induced a replenishment of the colonic Lgr5+ stem cell pool, whereas low-dose-rate radiation did not. To identify key molecules that determine the dose-rate effects on this stem cell pool, we harvested colonic Lgr5+ stem cells by cell sorting at 2 weeks after exposure to 1 Gy of high-dose-rate (30 Gy/h) or low-dose-rate (0.003 Gy/h) radiation and analyzed their gene expression profiles using RNA-Seq. We found that pathways related to DNA damage response, cell growth, cell differentiation and cell death were upregulated in Lgr5+ stem cells irradiated with high dose rates, whereas pathways related to apical junctions and extracellular signaling were upregulated in low-dose-rate-irradiated colonic Lgr5+ stem cells. Interestingly, biological events involving apical junctions are known to play an important role in the exclusion of transformed cells that are surrounded by normal epithelial cells through 'cell competition'. We speculated that cell competition, through apical junctions and extracellular ligands, might contribute to the dose-rate effect on Lgr5+ cell replenishment. To understand this mechanism, we focused on 69 genes that were significantly upregulated in low-dose-rate-irradiated cells, which we named DREDGE (Dose-Rate Effect Determining GEnes). Based on these findings, we propose a possible mechanism underlying the dose-rate effect observed in the colonic stem cell pool.
Collapse
Affiliation(s)
- Kensuke Otsuka
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwado-kita, Komae, Tokyo 201-8511, Japan
| | - Keiji Suzuki
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Yuki Fujimichi
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwado-kita, Komae, Tokyo 201-8511, Japan
| | - Masanori Tomita
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwado-kita, Komae, Tokyo 201-8511, Japan
| | - Toshiyasu Iwasaki
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwado-kita, Komae, Tokyo 201-8511, Japan
| |
Collapse
|
45
|
Rühm W, Azizova T, Bouffler S, Cullings HM, Grosche B, Little MP, Shore RS, Walsh L, Woloschak GE. Typical doses and dose rates in studies pertinent to radiation risk inference at low doses and low dose rates. JOURNAL OF RADIATION RESEARCH 2018; 59:ii1-ii10. [PMID: 29432579 PMCID: PMC5941142 DOI: 10.1093/jrr/rrx093] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/06/2017] [Accepted: 02/05/2018] [Indexed: 05/20/2023]
Abstract
In order to quantify radiation risks at exposure scenarios relevant for radiation protection, often extrapolation of data obtained at high doses and high dose rates down to low doses and low dose rates is needed. Task Group TG91 on 'Radiation Risk Inference at Low-dose and Low-dose Rate Exposure for Radiological Protection Purposes' of the International Commission on Radiological Protection is currently reviewing the relevant cellular, animal and human studies that could be used for that purpose. This paper provides an overview of dose rates and doses typically used or present in those studies, and compares them with doses and dose rates typical of those received by the A-bomb survivors in Japan.
Collapse
Affiliation(s)
- Werner Rühm
- Institute of Radiation Protection, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Tamara Azizova
- Southern Urals Biophysics Institute (SUBI), Ozyorskoe Shosse 19, 456780, Ozyorsk, Chelyabinsk Region, Russian Federation
| | - Simon Bouffler
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England (PHE), Chilton, Didcot OX11 ORQ, UK
| | - Harry M Cullings
- Radiation Effects Research Foundation, 5–2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Bernd Grosche
- Federal Office for Radiation Protection, Ingolstädter Landstr. 1, 85764 Oberschleißheim, Germany
| | - Mark P Little
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive, Bethesda, MD 20892-9778, USA
| | - Roy S Shore
- New York University School of Medicine, 650 First Ave., New York, NY 10016, USA
| | - Linda Walsh
- Medical Physics Group, Department of Physics, Science Faculty, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Gayle E Woloschak
- Departments of Radiation Oncology, Radiology, and Cell and Molecular Biology, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, 300 E. Superior St., Tarry 4-760, Chicago, IL 60611, USA
| |
Collapse
|
46
|
Affiliation(s)
- David G. Hoel
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| |
Collapse
|
47
|
Tran V, Little MP. Dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2017; 56:299-328. [PMID: 28939964 DOI: 10.1007/s00411-017-0707-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 08/06/2017] [Indexed: 06/07/2023]
Abstract
Murine experiments were conducted at the JANUS reactor in Argonne National Laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. The present study reports the reanalysis of the JANUS data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. Mice were mostly Mus musculus, but one experiment used Peromyscus leucopus. For both types of radiation exposure, a Cox proportional hazards model was used, using age as timescale, and stratifying on sex and experiment. The optimal model was one with linear and quadratic terms in cumulative lagged dose, with adjustments to both linear and quadratic dose terms for low-dose rate irradiation (<5 mGy/h) and with adjustments to the dose for age at exposure and sex. After gamma ray exposure there is significant non-linearity (generally with upward curvature) for all tumours, lymphoreticular, respiratory, connective tissue and gastrointestinal tumours, also for all non-tumour, other non-tumour, non-malignant pulmonary and non-malignant renal diseases (p < 0.001). Associated with this the low-dose extrapolation factor, measuring the overestimation in low-dose risk resulting from linear extrapolation is significantly elevated for lymphoreticular tumours 1.16 (95% CI 1.06, 1.31), elevated also for a number of non-malignant endpoints, specifically all non-tumour diseases, 1.63 (95% CI 1.43, 2.00), non-malignant pulmonary disease, 1.70 (95% CI 1.17, 2.76) and other non-tumour diseases, 1.47 (95% CI 1.29, 1.82). However, for a rather larger group of malignant endpoints the low-dose extrapolation factor is significantly less than 1 (implying downward curvature), with central estimates generally ranging from 0.2 to 0.8, in particular for tumours of the respiratory system, vasculature, ovary, kidney/urinary bladder and testis. For neutron exposure most endpoints, malignant and non-malignant, show downward curvature in the dose response, and for most endpoints this is statistically significant (p < 0.05). Associated with this, the low-dose extrapolation factor associated with neutron exposure is generally statistically significantly less than 1 for most malignant and non-malignant endpoints, with central estimates mostly in the range 0.1-0.9. In contrast to the situation at higher dose rates, there are statistically non-significant decreases of risk per unit dose at gamma dose rates of less than or equal to 5 mGy/h for most malignant endpoints, and generally non-significant increases in risk per unit dose at gamma dose rates ≤5 mGy/h for most non-malignant endpoints. Associated with this, the dose-rate extrapolation factor, the ratio of high dose-rate to low dose-rate (≤5 mGy/h) gamma dose response slopes, for many tumour sites is in the range 1.2-2.3, albeit not statistically significantly elevated from 1, while for most non-malignant endpoints the gamma dose-rate extrapolation factor is less than 1, with most estimates in the range 0.2-0.8. After neutron exposure there are non-significant indications of lower risk per unit dose at dose rates ≤5 mGy/h compared to higher dose rates for most malignant endpoints, and for all tumours (p = 0.001), and respiratory tumours (p = 0.007) this reduction is conventionally statistically significant; for most non-malignant outcomes risks per unit dose non-significantly increase at lower dose rates. Associated with this, the neutron dose-rate extrapolation factor is less than 1 for most malignant and non-malignant endpoints, in many cases statistically significantly so, with central estimates mostly in the range 0.0-0.2.
Collapse
Affiliation(s)
- Van Tran
- Radiation Epidemiology Branch, National Cancer Institute, Medical Center Drive 9609, MSC 9778, Rockville, MD, 20892-9778, USA
| | - Mark P Little
- Radiation Epidemiology Branch, National Cancer Institute, Medical Center Drive 9609, MSC 9778, Rockville, MD, 20892-9778, USA.
| |
Collapse
|
48
|
Chadwick KH. Towards a new dose and dose-rate effectiveness factor (DDREF)? Some comments. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2017; 37:422-433. [PMID: 28488593 DOI: 10.1088/1361-6498/aa6722] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The aim of this article is to offer a broader, mechanism-based, analytical tool than that used by (Rühm et al 2016 Ann. ICRP 45 262-79) for the interpretation of cancer induction relationships. The article explains the limitations of this broader analytical tool and the implications of its use in view of the publications by Leuraud et al 2015 (Lancet Haematol. 2 e276-81) and Richardson et al 2015 (Br. Med. J. 351 h5359). The publication by Rühm et al 2016 (Ann. ICRP 45 262-79), which is clearly work in progress, reviews the current status of the dose and dose-rate effectiveness factor (DDREF) as recommended by the ICRP. It also considers the issues which might influence a reassessment of both the value of the DDREF as well as its application in radiological protection. In this article, the problem is approached from a different perspective and starts by commenting on the limited scientific data used by Rühm et al 2016 (Ann. ICRP 45 262-79) to develop their analysis which ultimately leads them to use a linear-quadratic dose effect relationship to fit solid cancer mortality data from the Japanese life span study of atomic bomb survivors. The approach taken here includes more data on the induction of DNA double strand breaks and, using experimental data taken from the literature, directly relates the breaks to cell killing, chromosomal aberrations and somatic mutations. The relationships are expanded to describe the induction of cancer as arising from radiation induced cytological damage coupled to cell killing since the cancer mutated cell has to survive to express its malignant nature. Equations are derived for the induction of cancer after both acute and chronic exposure to sparsely ionising radiation. The equations are fitted to the induction of cancer in mice to illustrate a dose effect relationship over the total dose range. The 'DDREF' derived from the two equations varies with dose and the DDREF concept is called into question. Although the equation for acute exposure can be used to analyse atomic bomb survivor data, the fitting is dominated by the quadratic dose component. Thus, little useful information can be derived about the linear dose component which is important for the derivation of low dose rate risk. The ICRP are advised to derive the risk at low dose rates from epidemiological studies of, for example, worker populations, together with information from cellular radiation biological research.
Collapse
|
49
|
Shore R, Walsh L, Azizova T, Rühm W. Risk of solid cancer in low dose-rate radiation epidemiological studies and the dose-rate effectiveness factor. Int J Radiat Biol 2017; 93:1064-1078. [DOI: 10.1080/09553002.2017.1319090] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Roy Shore
- Environmental Medicine, New York University School of Medicine, New York, U.S.A
| | - Linda Walsh
- Department of Physics, University of Zurich, Zurich, Switzerland
| | - Tamara Azizova
- Clinical Department, Southern Urals Biophysics Institute, Ozyorsk, Russia
| | - Werner Rühm
- Department of Radiation Sciences, Institute of Radiation Protection, Helmholtz Centre Munich, Neuherberg, Germany
| |
Collapse
|
50
|
Matsuya Y, Tsutsumi K, Sasaki K, Yoshii Y, Kimura T, Date H. Modeling cell survival and change in amount of DNA during protracted irradiation. JOURNAL OF RADIATION RESEARCH 2017; 58:302-312. [PMID: 27974510 PMCID: PMC5465389 DOI: 10.1093/jrr/rrw110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/30/2016] [Indexed: 05/21/2023]
Abstract
Hyper-radiosensitivity (HRS) is a well-known bioresponse under low-dose or low-dose-rate exposures. Although disorder of the DNA repair function, non-targeted effects and accumulation of cells in G2 have been experimentally observed, the mechanism for inducing HRS by long-term irradiation is still unclear. On the basis of biological experiments and a theoretical study, we have shown that change in the amount of DNA associated with accumulation of cells in G2 enhances radiosensitivity. To demonstrate continuous irradiation with 250 kVp X-rays, we adopted a fractionated regimen of 0.186 or 1.00 Gy per fraction at intervals of 1 h (i.e. 0.186 Gy/h, 1.00 Gy/h on average) to Chinese Hamster Ovary (CHO)-K1 cells. The change in the amount of DNA during irradiation was quantified by flow cytometric analysis with propidium iodide (PI). Concurrently, we attempted a theoretical evaluation of the DNA damage by using a microdosimetric-kinetic (MK) model that was modified to incorporate the change in the amount of DNA. Our experimental results showed that the fraction of the cells in G2/M phase increased by 6.7% with 0.186 Gy/h and by 22.1% with 1.00 Gy/h after the 12th irradiation. The MK model considering the change in amount of DNA during the irradiation exhibited a higher radiosensitivity at a high dose range, which could account for the experimental clonogenic survival. The theoretical results suggest that HRS in the high dose range is associated with an increase in the total amount of DNA during irradiation.
Collapse
Affiliation(s)
- Yusuke Matsuya
- Graduate School of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo 060-0812, Japan
| | - Kaori Tsutsumi
- Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo 060-0812, Japan
| | - Kohei Sasaki
- Faculty of Health Sciences, Hokkaido University of Science, Maeda 7-15, Teine-ku, Sapporo 006-8585, Japan
| | - Yuji Yoshii
- Biological Research, Education and Instrumentation Center, Sapporo Medical University, Minami-1, Nichi-17, Chuo-ku, Sapporo 060-8556, Japan
| | - Takaaki Kimura
- Graduate School of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo 060-0812, Japan
| | - Hiroyuki Date
- Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo 060-0812, Japan
- Corresponding author. Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo 060-0812, Japan. Tel: +81-11-706-3423; Fax: +81-11-706-4916;
| |
Collapse
|