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Waisberg E, Ong J, Paladugu P, Kamran SA, Zaman N, Tavakkoli A, Lee AG. Radiation-induced ophthalmic risks of long duration spaceflight: Current investigations and interventions. Eur J Ophthalmol 2024; 34:1337-1345. [PMID: 38151034 DOI: 10.1177/11206721231221584] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
PURPOSE As the average duration of space missions increases, astronauts will experience longer periods of exposure to risks of long duration space flight including microgravity and radiation. The risks from long-term exposure to space radiation remains ill-defined. We review the current literature on the possible and known risks of radiation on the eye (including radiation retinopathy) after long duration spaceflight. METHODS A PubMed and Google Scholar search of the English language ophthalmic literature was performed from inception to July 11, 2022. The following search terms were utilized independently or in conjunction to build this manuscript: "Radiation Retinopathy", "Spaceflight", "Space Radiation", "Spaceflight Associated Neuro-Ocular Syndrome", "Microgravity", "Hypercapnia", "Radiation Shield", "Cataract", and "SANS". A concise and selective approach of references was conducted in including relevant original studies and reviews. RESULTS A total of 65 papers were reviewed and 47 papers were included in our review. CONCLUSION We discuss the potential and developing countermeasures to mitigate these radiation risks in preparation for future space exploration. Given the complex nature of space radiation, no single approach will fully reduce the risks of developing radiation maculopathy in long-duration spaceflight. Understanding and appropriately overcoming the risks of space radiation is key to becoming a multi-planetary species.
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Affiliation(s)
- Ethan Waisberg
- Department of Ophthalmology, University of Cambridge, Cambridge, United Kingdom
- University College Dublin School of Medicine, Belfield, Dublin, Ireland
| | - Joshua Ong
- Department of Ophthalmology, Michigan Medicine, University of Michigan, Ann Arbor, USA
| | - Phani Paladugu
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sharif Amit Kamran
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, Nevada, USA
| | - Nasif Zaman
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, Nevada, USA
| | - Alireza Tavakkoli
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, Nevada, USA
| | - Andrew G Lee
- Center for Space Medicine, Baylor College of Medicine, Houston, Texas, USA
- Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas, USA
- Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, USA
- Departments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medicine, New York, New York, USA
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, USA
- University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Texas A&M College of Medicine, Bryant, Texas, USA
- Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
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2
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Little MP, Bazyka D, de Gonzalez AB, Brenner AV, Chumak VV, Cullings HM, Daniels RD, French B, Grant E, Hamada N, Hauptmann M, Kendall GM, Laurier D, Lee C, Lee WJ, Linet MS, Mabuchi K, Morton LM, Muirhead CR, Preston DL, Rajaraman P, Richardson DB, Sakata R, Samet JM, Simon SL, Sugiyama H, Wakeford R, Zablotska LB. A Historical Survey of Key Epidemiological Studies of Ionizing Radiation Exposure. Radiat Res 2024; 202:432-487. [PMID: 39021204 PMCID: PMC11316622 DOI: 10.1667/rade-24-00021.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/23/2024] [Indexed: 07/20/2024]
Abstract
In this article we review the history of key epidemiological studies of populations exposed to ionizing radiation. We highlight historical and recent findings regarding radiation-associated risks for incidence and mortality of cancer and non-cancer outcomes with emphasis on study design and methods of exposure assessment and dose estimation along with brief consideration of sources of bias for a few of the more important studies. We examine the findings from the epidemiological studies of the Japanese atomic bomb survivors, persons exposed to radiation for diagnostic or therapeutic purposes, those exposed to environmental sources including Chornobyl and other reactor accidents, and occupationally exposed cohorts. We also summarize results of pooled studies. These summaries are necessarily brief, but we provide references to more detailed information. We discuss possible future directions of study, to include assessment of susceptible populations, and possible new populations, data sources, study designs and methods of analysis.
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Affiliation(s)
- Mark P. Little
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
- Faculty of Health and Life Sciences, Oxford Brookes University, Headington Campus, Oxford, OX3 0BP, UK
| | - Dimitry Bazyka
- National Research Center for Radiation Medicine, Hematology and Oncology, 53 Melnikov Street, Kyiv 04050, Ukraine
| | | | - Alina V. Brenner
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Vadim V. Chumak
- National Research Center for Radiation Medicine, Hematology and Oncology, 53 Melnikov Street, Kyiv 04050, Ukraine
| | - Harry M. Cullings
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Robert D. Daniels
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Benjamin French
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Eric Grant
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194, Japan
| | - Michael Hauptmann
- Institute of Biostatistics and Registry Research, Brandenburg Medical School Theodor Fontane, 16816 Neuruppin, Germany
| | - Gerald M. Kendall
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Headington, Oxford, OX3 7LF, UK
| | - Dominique Laurier
- Institute for Radiological Protection and Nuclear Safety, Fontenay aux Roses France
| | - Choonsik Lee
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Won Jin Lee
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, South Korea
| | - Martha S. Linet
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Kiyohiko Mabuchi
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Lindsay M. Morton
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | | | | | - Preetha Rajaraman
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - David B. Richardson
- Environmental and Occupational Health, 653 East Peltason, University California, Irvine, Irvine, CA 92697-3957 USA
| | - Ritsu Sakata
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Jonathan M. Samet
- Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado, USA
| | - Steven L. Simon
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Hiromi Sugiyama
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Richard Wakeford
- Centre for Occupational and Environmental Health, The University of Manchester, Ellen Wilkinson Building, Oxford Road, Manchester, M13 9PL, UK
| | - Lydia B. Zablotska
- Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, 550 16 Street, 2 floor, San Francisco, CA 94143, USA
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Hamada N. Noncancer Effects of Ionizing Radiation Exposure on the Eye, the Circulatory System and beyond: Developments made since the 2011 ICRP Statement on Tissue Reactions. Radiat Res 2023; 200:188-216. [PMID: 37410098 DOI: 10.1667/rade-23-00030.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/13/2023] [Indexed: 07/07/2023]
Abstract
For radiation protection purposes, noncancer effects with a threshold-type dose-response relationship have been classified as tissue reactions (formerly called nonstochastic or deterministic effects), and equivalent dose limits aim to prevent occurrence of such tissue reactions. Accumulating evidence demonstrates increased risks for several late occurring noncancer effects at doses and dose rates much lower than previously considered. In 2011, the International Commission on Radiological Protection (ICRP) issued a statement on tissue reactions to recommend a threshold of 0.5 Gy to the lens of the eye for cataracts and to the heart and brain for diseases of the circulatory system (DCS), independent of dose rate. Literature published thereafter continues to provide updated knowledge. Increased risks for cataracts below 0.5 Gy have been reported in several cohorts (e.g., including in those receiving protracted or chronic exposures). A dose threshold for cataracts is less evident with longer follow-up, with limited evidence available for risk of cataract removal surgery. There is emerging evidence for risk of normal-tension glaucoma and diabetic retinopathy, but the long-held tenet that the lens represents among the most radiosensitive tissues in the eye and in the body seems to remain unchanged. For DCS, increased risks have been reported in various cohorts, but the existence or otherwise of a dose threshold is unclear. The level of risk is less uncertain at lower dose and lower dose rate, with the possibility that risk per unit dose is greater at lower doses and dose rates. Target organs and tissues for DCS are also unknown, but may include heart, large blood vessels and kidneys. Identification of potential factors (e.g., sex, age, lifestyle factors, coexposures, comorbidities, genetics and epigenetics) that may modify radiation risk of cataracts and DCS would be important. Other noncancer effects on the radar include neurological effects (e.g., Parkinson's disease, Alzheimer's disease and dementia) of which elevated risk has increasingly been reported. These late occurring noncancer effects tend to deviate from the definition of tissue reactions, necessitating more scientific developments to reconsider the radiation effect classification system and risk management. This paper gives an overview of historical developments made in ICRP prior to the 2011 statement and an update on relevant developments made since the 2011 ICRP statement.
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Affiliation(s)
- Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Chiba, Japan
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Yokoyama S, Hamada N, Tsujimura N, Kunugita N, Nishida K, Ezaki I, Kato M, Okubo H. Regulatory implementation of the occupational equivalent dose limit for the lens of the eye and underlying relevant efforts in Japan. Int J Radiat Biol 2023; 99:604-619. [PMID: 35980737 DOI: 10.1080/09553002.2022.2115160] [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: 10/15/2022]
Abstract
In April 2011, the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens. Such a new occupational lens dose limit has thus far been implemented in many countries, and there are extensive discussions toward its regulatory implementation in other countries. In Japan, discussions in the Japan Health Physics Society (JHPS) began in April 2013 and in Radiation Council in July 2017, and the new occupational lens dose limit was implemented into regulation in April 2021. To share our experience, we have published a series of papers summarizing situations in Japan: the first paper based on information available by early 2017, and the second paper by early 2019. This paper (our third paper of this series) aims to review updated information available by mid-2022, such as regarding regulatory implementation of the new occupational lens dose limit, recent discussions by relevant ministries based on the opinion from the council, establishment process of safety and health management systems, the JHPS guidelines on lens dose monitoring and radiation safety, voluntary countermeasures of the licensees, development of lens dose calibration method, and recent studies on exposure of the lens in nuclear workers and biological effect on the lens.
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Affiliation(s)
- Sumi Yokoyama
- Research Promotion Headquarters, Fujita Health University, Aichi, Japan
| | - Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan
| | - Norio Tsujimura
- Radiation Protection Department, Japan Atomic Energy Agency, Ibaraki, Japan
| | - Naoki Kunugita
- School of Health Sciences, University of Occupational and Environmental Health, Fukuoka, Japan
| | - Kazutaka Nishida
- Radiological Management Group, Kansai Electric Power Co., Inc, Fukui, Japan
| | - Iwao Ezaki
- Technical Group, Nuclear Power Plant Business Headquarters, Chiyoda Technol Corporation, Tokyo, Japan
| | - Masahiro Kato
- Ionizing Radiation Standards Group, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Hideki Okubo
- Radiological Health and Safety Center Nuclear Safe Management Department, Tokyo Electric Power Company Holdings, Inc, Tokyo, Japan
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Azizova TV, Bragin EV, Bannikova MV, Hamada N, Grigoryeva ES. The Incidence Risk for Primary Glaucoma and Its Subtypes following Chronic Exposure to Ionizing Radiation in the Russian Cohort of Mayak Nuclear Workers. Cancers (Basel) 2022; 14:cancers14030602. [PMID: 35158870 PMCID: PMC8833586 DOI: 10.3390/cancers14030602] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Glaucoma is a leading cause of irreversible blindness worldwide and also represents one of the normal tissue complications following radiation therapy involving ocular radiation exposure. It has widely been considered that such secondary glaucoma occurs at fractionated high dose (several tens of Gy). In contrast, this study is the first to report that normal-tension glaucoma (a subtype of primary open-angle glaucoma) occurs in radiation workers at a chronic dose of >1 Gy. Such elevated risk of radiogenic normal-tension glaucoma, if confirmed in other cohorts, has significant implications for normal tissue complications in radiotherapy patients receiving ocular radiation exposure, and for ocular radiation protection in radiation workers. Abstract Secondary glaucoma is a typical normal tissue complication following radiation therapy involving ocular radiation exposure at high fractionated dose (several tens of Gy). In contrast, recent studies in acutely exposed Japanese atomic bomb survivors showed a significantly increased risk for normal-tension glaucoma (NTG, a subtype of primary open-angle glaucoma) at much lower dose, but such information is not available in any other cohorts. We therefore set out to evaluate the incidence of risk for primary glaucoma and its subtypes in a Russian cohort of Mayak Production Association nuclear workers who received chronic radiation exposure over many years. Of these, we found a significantly increased relative risk (RR) of NTG incidence (RR = 1.88 95% confidence intervals (CI): 1.01, 3.51; p = 0.047) in workers exposed to gamma rays at cumulative brain absorbed dose above >1 Gy. We observed the linear relationship between NTG incidence and brain absorbed gamma dose with an excess relative risk per unit brain absorbed dose of 0.53 (95% CI: 0.01, 1.68; p < 0.05), but not for any other subtypes nor for total primary glaucoma. Such elevated risk of radiogenic NTG incidence, if confirmed in other cohorts, has significant implications for normal tissue complications in radiotherapy patients receiving ocular radiation exposure, and for ocular radiation protection in radiation workers.
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Affiliation(s)
- Tamara V. Azizova
- Clinical Department, Southern Urals Biophysics Institute (SUBI), 456780 Ozyorsk, Russia; (E.V.B.); (M.V.B.); (E.S.G.)
- Correspondence:
| | - Evgeny V. Bragin
- Clinical Department, Southern Urals Biophysics Institute (SUBI), 456780 Ozyorsk, Russia; (E.V.B.); (M.V.B.); (E.S.G.)
| | - Maria V. Bannikova
- Clinical Department, Southern Urals Biophysics Institute (SUBI), 456780 Ozyorsk, Russia; (E.V.B.); (M.V.B.); (E.S.G.)
| | - Nobuyuki Hamada
- Radiation Safety Unit, Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo 201-8511, Japan;
| | - Evgeniya S. Grigoryeva
- Clinical Department, Southern Urals Biophysics Institute (SUBI), 456780 Ozyorsk, Russia; (E.V.B.); (M.V.B.); (E.S.G.)
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6
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Little MP, Azizova TV, Hamada N. Low- and moderate-dose non-cancer effects of ionizing radiation in directly exposed individuals, especially circulatory and ocular diseases: a review of the epidemiology. Int J Radiat Biol 2021; 97:782-803. [PMID: 33471563 PMCID: PMC10656152 DOI: 10.1080/09553002.2021.1876955] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/24/2020] [Accepted: 01/09/2021] [Indexed: 01/29/2023]
Abstract
PURPOSE There are well-known correlations between high and moderate doses (>0.5 Gy) of ionizing radiation exposure and circulatory system damage, also between radiation and posterior subcapsular cataract. At lower dose correlations with circulatory disease are emerging in the Japanese atomic bomb survivors and in some occupationally exposed groups, and are still to some extent controversial. Heterogeneity in excess relative risks per unit dose in epidemiological studies at low (<0.1 Gy) and at low-moderate (>0.1 Gy, <0.5 Gy) doses may result from confounding and other types of bias, and effect modification by established risk factors. There is also accumulating evidence of excess cataract risks at lower dose and low dose rate in various cohorts. Other ocular endpoints, specifically glaucoma and macular degeneration have been little studied. In this paper, we review recent epidemiological findings, and also discuss some of the underlying radiobiology of these conditions. We briefly review some other types of mainly neurological nonmalignant disease in relation to radiation exposure. CONCLUSIONS We document statistically significant excess risk of the major types of circulatory disease, specifically ischemic heart disease and stroke, in moderate- or low-dose exposed groups, with some not altogether consistent evidence suggesting dose-response non-linearity, particularly for stroke. However, the patterns of risk reported are not straightforward. We also document evidence of excess risks at lower doses/dose-rates of posterior subcapsular and cortical cataract in the Chernobyl liquidators, US Radiologic Technologists and Russian Mayak nuclear workers, with fundamentally linear dose-response. Nuclear cataracts are less radiogenic. For other ocular endpoints, specifically glaucoma and macular degeneration there is very little evidence of effects at low doses; radiation-associated glaucoma has been documented only for doses >5 Gy, and so has the characteristics of a tissue reaction. There is some evidence of neurological detriment following low-moderate dose (∼0.1-0.2 Gy) radiation exposure in utero or in early childhood.
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Affiliation(s)
- Mark P Little
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD, USA
| | - Tamara V Azizova
- Clinical Department, Southern Urals Biophysics Institute, Ozyorsk, Ozyorsk Chelyabinsk Region, Russia
| | - Nobuyuki Hamada
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Komae, Tokyo, Japan
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Ainsbury EA, Dalke C, Hamada N, Benadjaoud MA, Chumak V, Ginjaume M, Kok JL, Mancuso M, Sabatier L, Struelens L, Thariat J, Jourdain JR. Radiation-induced lens opacities: Epidemiological, clinical and experimental evidence, methodological issues, research gaps and strategy. ENVIRONMENT INTERNATIONAL 2021; 146:106213. [PMID: 33276315 DOI: 10.1016/j.envint.2020.106213] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/11/2020] [Accepted: 08/25/2020] [Indexed: 06/12/2023]
Abstract
In 2011, the International Commission on Radiological Protection (ICRP) recommended reducing the occupational equivalent dose limit for the lens of the eye from 150 mSv/year to 20 mSv/year, averaged over five years, with no single year exceeding 50 mSv. With this recommendation, several important assumptions were made, such as lack of dose rate effect, classification of cataracts as a tissue reaction with a dose threshold at 0.5 Gy, and progression of minor opacities into vision-impairing cataracts. However, although new dose thresholds and occupational dose limits have been set for radiation-induced cataract, ICRP clearly states that the recommendations are chiefly based on epidemiological evidence because there are a very small number of studies that provide explicit biological and mechanistic evidence at doses under 2 Gy. Since the release of the 2011 ICRP statement, the Multidisciplinary European Low Dose Initiative (MELODI) supported in April 2019 a scientific workshop that aimed to review epidemiological, clinical and biological evidence for radiation-induced cataracts. The purpose of this article is to present and discuss recent related epidemiological and clinical studies, ophthalmic examination techniques, biological and mechanistic knowledge, and to identify research gaps, towards the implementation of a research strategy for future studies on radiation-induced lens opacities. The authors recommend particularly to study the effect of ionizing radiation on the lens in the context of the wider, systemic effects, including in the retina, brain and other organs, and as such cataract is recommended to be studied as part of larger scale programs focused on multiple radiation health effects.
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Affiliation(s)
- Elizabeth A Ainsbury
- Public Health England (PHE) Centre for Radiation, Chemical and Environmental Hazards, Oxon, United Kingdom.
| | - Claudia Dalke
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Germany.
| | - Nobuyuki Hamada
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan.
| | - Mohamed Amine Benadjaoud
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), BP 17, 31 avenue de la division Leclerc, Fontenay-aux-Roses, France.
| | - Vadim Chumak
- National Research Centre for Radiation Medicine, Ukraine.
| | | | - Judith L Kok
- Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands.
| | - Mariateresa Mancuso
- Laboratory of Biomedical Technologies, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, (ENEA), Rome, Italy.
| | - Laure Sabatier
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Saclay, France.
| | | | - Juliette Thariat
- Laboratoire de physique corpusculaire IN2P3/ENSICAEN -UMR6534 - Unicaen - Normandie University, France
| | - Jean-René Jourdain
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), BP 17, 31 avenue de la division Leclerc, Fontenay-aux-Roses, France.
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Laiakis EC, Chauhan V, Little MP, Woloschak GE, Weil MM, Hamada N. Summary of the Second Bill Morgan Memorial Symposium: an update on low dose biology, epidemiology, its integration and implications for radiation protection. Int J Radiat Biol 2020; 97:861-865. [PMID: 33252285 PMCID: PMC10655691 DOI: 10.1080/09553002.2020.1855373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/21/2022]
Affiliation(s)
- Evagelia C. Laiakis
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON K1A 0K9, Canada
| | - Mark P. Little
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Gayle E. Woloschak
- Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Michael M. Weil
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Nobuyuki Hamada
- 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
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9
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Hamada N, Azizova TV, Little MP. An update on effects of ionizing radiation exposure on the eye. Br J Radiol 2020; 93:20190829. [PMID: 31670577 PMCID: PMC8519632 DOI: 10.1259/bjr.20190829] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/20/2019] [Accepted: 10/26/2019] [Indexed: 12/18/2022] Open
Abstract
The International Commission on Radiological Protection (ICRP) has considered for over 60 years that the lens of the eye is among the most radiosensitive tissues, and has recommended dose limits for the lens to prevent occurrence of vision impairing cataracts (VICs). Epidemiological evidence that doses much lower than previously thought produce cataracts led ICRP to recommend reducing dose threshold for VICs and reducing an occupational equivalent dose limit for the lens in 2011, when only a single threshold of 0.5 Gy was recommended. On the basis of epidemiological evidence, ICRP assumed progression of minor opacities into VICs and no dose rate effect. This contrasts with previously recommended separate thresholds for minor opacities and VICs, and for different exposure scenarios. Progression was assumed based on similar risks of cataracts and cataract surgery in Japanese atomic bomb survivors. The absence of dose rate effect derived from the observed similar thresholds for protracted exposures in Chernobyl cleanup workers and in atomic bomb survivors. Since 2011, there has been an increasing body of epidemiological evidence relating to cataracts and other ocular diseases (i.e. glaucoma and macular degeneration), particularly at low doses and low dose rates. This review paper gives an overview of the scientific basis of the 2011 ICRP recommendation, discusses the plausibility of these two assumptions in the light of emerging scientific evidence, and considers the radiosensitivity of the lens among ocular structures.
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Affiliation(s)
- Nobuyuki Hamada
- 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
| | - Tamara V. Azizova
- Clinical Department, Southern Urals Biophysics Institute (SUBI), Ozyorskoe Shosse 19, Ozyorsk Chelyabinsk Region, 456780, Ozersk, Russia
| | - Mark P. Little
- Radiation Epidemiology Branch, National Cancer Institute (NCI), National Institutes of Health (NIH), 9609 Medical Center Drive, MSC 9778, Bethesda, MD 20892-9778, USA
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10
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Pathophysiology and management of glaucoma and ocular hypertension related to trauma. Surv Ophthalmol 2020; 65:530-547. [PMID: 32057763 DOI: 10.1016/j.survophthal.2020.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 12/21/2022]
Abstract
Ocular trauma is a significant cause of blindness worldwide, particularly if associated with glaucoma. Direct damage from blunt or penetrating trauma, bleeding, inflammation, lens-related problems, orbital and brain vascular pathologies related to trauma, and chemical injuries may increase intraocular pressure and lead to traumatic glaucoma. Treatment may be as simple as eliminating the underlying cause in some conditions or management can be challenging, depending on the mechanism of damage. If proper management is not undertaken, visual outcomes can be poor. We discuss a broad spectrum of trauma-related mechanisms of intraocular pressure elevation, as well as their management.
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11
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Glaucoma incidence risk in a cohort of Mayak PA workers occupationally exposed to ionizing radiation. Sci Rep 2019; 9:12469. [PMID: 31462740 PMCID: PMC6713741 DOI: 10.1038/s41598-019-48915-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 08/15/2019] [Indexed: 11/20/2022] Open
Abstract
Glaucoma is a major cause of visual impairment, and secondary glaucoma manifested as neovascular glaucoma has long been known to occur following high-dose fractionated radiation therapy. In contrast, little is known as to whether ionizing radiation exposure causes primary glaucoma, except that a single study in Japanese atomic bomb survivors has reported a significantly increase risk. Therefore, the effect of lower dose and lower dose rate remains unclear. Here we report that in Russian Mayak Production Association workers occupationally exposed to chronic radiation for prolonged periods, incidence of total primary glaucoma and primary open-angle glaucoma is significantly associated with various non-radiation factors (sex, attained age, and cataract diagnosed prior to glaucoma), but neither with cumulative dose from external γ-rays nor with cumulative neutron dose nor with the unweighted sum of cumulative γ and neutron doses. The present results suggest for the first time that chronic radiation exposure does not cause primary glaucoma, although the analyses need to be made in other cohorts exposed at various dose and dose rate.
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Kiuchi Y, Yanagi M, Itakura K, Takahashi I, Hida A, Ohishi W, Furukawa K. Association between radiation, glaucoma subtype, and retinal vessel diameter in atomic bomb survivors. Sci Rep 2019; 9:8642. [PMID: 31201344 PMCID: PMC6570769 DOI: 10.1038/s41598-019-45049-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/31/2019] [Indexed: 01/10/2023] Open
Abstract
We examined the relationship between glaucoma subtype and retinal vascular caliber as markers of ocular circulation. Subjects were Japanese atomic bomb survivors in Hiroshima and Nagasaki. After a screening examination, potential cases were subjected to further definitive examination. The diameters of central retinal artery and vein equivalents (CRAE and CRVE) on digitized retinal photographs were measured using an established method. Generalized linear regression analyses were used to examine the associations among vessel diameters, radiation exposure, and prevalence of glaucoma subtypes among the study subjects. We identified 196 cases of glaucoma (12%) based on optic disc appearance, perimetry results, and other ocular findings. The main subtypes were primary angle-closure glaucoma, primary open-angle glaucoma and normal-tension glaucoma (NTG). NTG was the dominant subtype (78%). NTG was negatively associated with CRAE and CRVE, and positively associated with radiation dose. CRVE was negatively associated with radiation dose and the association was unclear for CRAE. The smaller retinal vessel caliber in NTG patients than in subjects without glaucoma may indicate an association between ocular blood flow and the pathogenesis of NTG. However, significant relationships among vessel calibers, NTG and radiation exposure were not clear.
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Affiliation(s)
- Yoshiaki Kiuchi
- Department of Ophthalmology and Visual Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
| | - Masahide Yanagi
- Department of Ophthalmology and Visual Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Katsumasa Itakura
- Department of Ophthalmology and Visual Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Ikuno Takahashi
- Department of Clinical Studies, Radiation Effects Research Foundation (RERF), 5-2 Hijiyama Park, Minami-ku, Hiroshima, 732-0815, Japan
| | - Ayumi Hida
- Department of Clinical Studies, Radiation Effects Research Foundation (RERF), 5-2 Hijiyama Park, Minami-ku, Hiroshima, 732-0815, Japan
| | - Waka Ohishi
- Department of Clinical Studies, Radiation Effects Research Foundation (RERF), 5-2 Hijiyama Park, Minami-ku, Hiroshima, 732-0815, Japan
| | - Kyoji Furukawa
- Biostatistics Center, Kurume University, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
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Yokoyama S, Hamada N, Tsujimura N. Recent discussions toward regulatory implementation of the new occupational equivalent dose limit for the lens of the eye and related studies in Japan. Int J Radiat Biol 2019; 95:1103-1112. [PMID: 30964367 DOI: 10.1080/09553002.2019.1605464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Purpose: In 2011, the International Commission on Radiological Protection (ICRP) recommended an equivalent dose limit for the lens of the eye of 20 mSv/year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv for occupational exposure in planned exposure situations. Since then, there have been extensive discussions toward regulatory implementation of such a new occupational lens dose limit. This paper provides an overview of the recent discussions toward regulatory implementation and the current status of the studies related to radiation exposure of the lens and its effect in Japan. Conclusions: In Japan, the Radiation Council established a Subcommittee in July 2017 to discuss the feasibility of implementing the new occupational lens dose limit. In March 2018, the Radiation Council requested all relevant government ministries and agencies to take necessary actions toward implementation of the new occupational lens dose limit, considering a series of discussions made by the Subcommittee. According to the currently available information, the new occupational lens dose limit (20 mSv/year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv) will be implemented into regulations in Japan, most likely in April 2021, albeit subject to change. In particular, there were extensive discussions about reduction of a dose limit and radiation control for workers who may exceed 20 mSv per year, such as the Fukushima Daiichi Nuclear Power Plant decommissioning workers and medical staff, and measurement of 3 mm dose equivalent. In order to underpin regulatory practice, epidemiological and biological studies on radiation effects on the lens and studies on lens dose measurements have been conducted in Japan, some of which have been funded by the Japanese Nuclear Regulation Authority.
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Affiliation(s)
- Sumi Yokoyama
- a Faculty of Radiological Technology, School of Medical Sciences, Fujita Health University , Aichi , Japan
| | - Nobuyuki Hamada
- b Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI) , Tokyo , Japan
| | - Norio Tsujimura
- c Radiation Protection Department, Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency , Ibaraki , Japan
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Hamada N, Azizova TV, Little MP. Glaucomagenesis following ionizing radiation exposure. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2019; 779:36-44. [PMID: 31097150 PMCID: PMC10654893 DOI: 10.1016/j.mrrev.2019.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/02/2019] [Accepted: 01/07/2019] [Indexed: 12/31/2022]
Abstract
Glaucoma is a group of optic neuropathies causing optic nerve damage and visual field defects, and is one of the leading causes of blindness. Nearly a century has passed since the first report of glaucoma manifested following ionizing radiation therapy of cancers. Nevertheless, associations between glaucoma and radiation exposures, a dose response relationship, and the mechanistic underpinnings remain incompletely understood. Here we review the current knowledge on manifestations and mechanisms of radiogenic glaucoma. There is some evidence that neovascular glaucoma is manifest relatively quickly, within a few years after high-dose and high dose-rate radiotherapeutic exposure, but little evidence of excess risks of glaucoma after exposure to much lower doses or dose rates. As such, glaucoma appears to have some of the characteristics of a tissue reaction effect, with a threshold of at least 5 Gy but possibly much higher.
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Affiliation(s)
- Nobuyuki Hamada
- 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.
| | - Tamara V Azizova
- Clinical Department, Southern Urals Biophysics Institute, Ozyorskoe Shosse 19, Ozyorsk Chelyabinsk Region, 456780, Russia.
| | - Mark P Little
- Radiation Epidemiology Branch, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, MSC 9778, Bethesda, MD, 20892-9778, USA.
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