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Nessipkhan A, Matsuda N, Takamura N, Oriuchi N, Ito H, Kiguchi M, Nishihara K, Tamaru T, Awai K, Kudo T. Occupational radiation exposure among medical personnel in university and general hospitals in Japan. Jpn J Radiol 2024:10.1007/s11604-024-01579-3. [PMID: 38705937 DOI: 10.1007/s11604-024-01579-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/20/2024] [Indexed: 05/07/2024]
Abstract
OBJECTIVE This study aimed to compare the occupational radiation exposure of medical workers between general hospitals and university hospitals. METHODS Radiation exposure data from three hospitals in Hiroshima city, including one university hospital and two general hospitals, were collected using personal dosimeters. Monthly radiation doses were analyzed, and the annual sum of radiation exposure dose was calculated for 538 subjects in general hospitals and 1224 subjects in the university hospital. To assess the impact of locality, additional data from Nagasaki University Hospital and Fukushima Medical University Hospital were included for comparative analysis. Professional affiliations, such as doctors, nurses, and radiological technologists, were considered in the evaluation. RESULTS The study revealed slight but significant differences in radiation doses between general and university hospitals. In general hospitals, except for radiological technologists, a slightly higher radiation dose was observed compared to university hospitals. Despite the annual increase in the use of medical radiation, the majority of hospital workers in both settings adhered to safety guidelines, with occupational radiation exposure remaining below the limit of detection (LOD). Workers who involved in fluoroscopic procedure, whether at university or general hospitals, had higher radiation doses than those who did not. CONCLUSION The study's primary conclusion is that workers in general hospitals experience a slight but significantly higher radiation dose and a lower percentage below the LOD compared to university hospitals. The observed difference is attributed to the greater workload at general hospitals than at university hospitals, and also may be due to the different nature of university hospital and general hospital. University hospitals, characterized by greater academic orientation, tend to benefit from comprehensive support systems, specialized expertise, and advanced technology, leading to more structured and regulated radiation control. These findings provide a basis for targeted interventions, improved safety protocols.
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Affiliation(s)
- Arman Nessipkhan
- Department of Radioisotope Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan.
| | - Naoki Matsuda
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Noboru Takamura
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Noboru Oriuchi
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, Fukushima, Japan
| | - Hiroshi Ito
- Department of Radiology, Faculty of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Masao Kiguchi
- Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan
| | - Kiyoto Nishihara
- Department of Radiological Technology, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan
| | - Takayuki Tamaru
- Department of Radiology, JA Hiroshima General Hospital, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takashi Kudo
- Department of Radioisotope Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
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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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Radiation doses to the eye lenses of radiologic technologists who assist patients undergoing computed tomography. Radiol Phys Technol 2021; 14:167-172. [PMID: 34014503 DOI: 10.1007/s12194-021-00613-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 03/07/2021] [Accepted: 03/10/2021] [Indexed: 10/21/2022]
Abstract
The present study aimed to determine the amount of radiation exposure to the eye lenses of radiologic technologists while assisting patients undergoing computed tomography imaging and the effects of wearing lead glasses on dose reduction. Monthly radiation doses were collected for 12 months. Dose quantities at a depth of 3 mm (Hp(3)) were measured at the neck using personal optically stimulated luminescence (OSL) dosimeters. We also estimated Hp(3) as converted air kerma using small OSL dosimeters at the neck and at six positions on the lead glasses near the eyes. The total dose-length product at the time of patient assistance was 53,341 mGy·cm/y. The Hp(3) from the personal dosimeter was 9.13 mSv/y and the highest dose recorded by the small OSL dosimeters attached outside the lead glasses was 8.47 mSv/y. The lead glasses reduced the radiation exposure by ~ 60%.
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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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Cantone MC, Ginjaume M, Martin CJ, Hamada N, Yokoyama S, Bordy JM, Dauer L, Durán A, Jeffries C, Harris W, Kashirina O, Koteng AO, Michelin S, Sudchai W. Report of IRPA task group on issues and actions taken in response to the change in eye lens dose limit. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2020; 40:1508-1533. [PMID: 33226005 DOI: 10.1088/1361-6498/abb5ec] [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: 08/21/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
In 2018, the International Radiation Protection Association (IRPA) established its third task group (TG) on the implementation of the eye lens dose limit. To contribute to sharing experience and raising awareness within the radiation protection community about protection of workers in exposure of the lens of the eye, the TG conducted a questionnaire survey and analysed the responses. This paper provides an overview of the results of the questionnaire.
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Affiliation(s)
| | - Merce Ginjaume
- Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Colin J Martin
- University of Glasgow, Gartnavel Royal Hospital, Glasgow, United Kingdom
| | - Nobuyuki Hamada
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan
| | | | - Jean-Marc Bordy
- CEA, LIST, Laboratoire National Henri Becquerel, F-91191, Gif-sur-Yvette, France
| | - Lawrence Dauer
- Memorial Sloan Kettering Cancer Center, Department of Medical Physics, New York, United States of America
| | - Ariel Durán
- University Hospital, Montevideo School of Medicine, Montevideo, Uruguay
| | - Cameron Jeffries
- Flinders Medical Centre, Flinders Drive, South Australia, Australia
| | - Willie Harris
- Exelon Nuclear, 200 Exelon Way, United States of America
| | - Olga Kashirina
- Burnazyan Federal Medical Biophysical Centre, Federal Medical Biological Agency, Moscow, Russia
| | - Arthur Omondi Koteng
- Kenia Radiation Protection Board, RPB, Eastern Africa Association for Radiation Protection, EAARP, Nairobi, Kenya
| | | | - Waraporn Sudchai
- TINT, Thailand Institute of Nuclear Technology, Bangkok, Thailand
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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: 39] [Impact Index Per Article: 9.8] [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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Tsujimura N, Yamazaki T, Takada C. Present status and practical issues on dosimetry for the lens of the eye at JAEA MOX fuel facilities. J NUCL SCI TECHNOL 2020. [DOI: 10.1080/00223131.2020.1796837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Norio Tsujimura
- Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Ibaraki, Japan
| | - Takumi Yamazaki
- Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Ibaraki, Japan
| | - Chie Takada
- Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Ibaraki, Japan
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Hoshi K, Yoshitomi H, Aoki K, Tanimura Y, Tsujimura N, Yokoyama S. Eye lens dosimetry for workers at Fukushima Daiichi Nuclear Power Plant—1: Laboratory study on the dosemeter position and the shielding effect of full face mask respirators. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Tsujimura N, Hoshi K, Aoki K, Yoshitomi H, Tanimura Y, Yokoyama S. Eye lens dosimetry for workers at Fukushima Daiichi Nuclear Power Plant—2: Field study using humanoid phantoms. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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