Occupational radiation exposure among medical personnel in university and general hospitals in Japan.

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.

Radiation Exposure Characteristics among Healthcare Workers: Before and After Japan's Ordinance Revision.

ABSTRACT: Radioactive materials and ionizing radiation have both medical value and disease risks, necessitating radiation dose measurement and risk reduction strategies. The International Commission on Radiological Protection (ICRP) lowered the lens of the eye exposure limit, leading to Japan's revised "Ionizing Radiation Ordinance." However, the effects on radiation exposure in medical settings and compliance feasibility remain unclear. To examine the impact of the revision to the "Ionizing Radiation Ordinance" and use it for measures to reduce exposure to radiation, a comprehensive analysis was conducted on data collected from Nagasaki University Hospital, Hiroshima University Hospital, and Fukushima Medical University Hospital in 2018, 2020, and April to September 2021. This included information on age, sex, occupation, department, and monthly radiation doses of workers, aiming to assess the impact of the revision to the "Ionizing Radiation Ordinance" on radiation exposure before and after its enforcement. Out of 9,076 cases studied, 7,963 (87.7%) had radiation doses below the measurable limit throughout the year. Only 292 cases (3.2%) exceeded 1 mSv y -1 , with 9 doctors and 2 radiological technologists surpassing 5 mSv y -1 . Radiological technologists showed significantly higher doses compared to doctors, dentists, and nurses (p < 0.01), while male subjects had significantly higher exposure doses than females (p < 0.01). No significant changes in radiation exposure were observed before and after the revision of the Ionizing Radiation Ordinance; however, variations in radiation exposure control were noted, particularly among nurses and radiological technologists, suggesting the impact of the revision and the need for tailored countermeasures to reduce radiation dose in each group.

Thoughts, perceptions and concerns of coastal residents regarding the discharge of tritium-containing treated water from the Fukushima Daiichi Nuclear Power Plant into the Pacific Ocean.

BACKGROUND: As a part of the decontamination process after the Fukushima Daiichi Nuclear Power Plant accident of 2011, 1.32 million tonnes of tritium-containing water will be discharged from the power plant into the Pacific Ocean. Although radiobiological impacts of the treated water discharge on the public and the environment were reported to be minimal, Tomioka and Okuma locals expressed unease regarding the long-term recovery of their towns, which are economically dependent on the agricultural, fishery, and tourism sectors. This study presents thoughts, perceptions and concerns of Tomioka and Okuma locals regarding the discharge of FDNPP-treated water containing tritium into the Pacific Ocean to facilitate a more inclusive decision-making process that respects local stakeholder interests. METHODS: Conducted from November to December 2022, surveys were mailed to current residents and evacuees aged 20 years or older registered with the town councils. RESULTS: Out of 1268 included responses, 71.5% were from those > 65 years. 65.6% were unemployed, 76.2% routinely visited hospitals, and 85.5% did not live with children. 61% did not want to return to Okuma/Tomioka. Anxiety about radiation-related health effects (38.7%), consuming food produced in Okuma/Tomioka (48.0%) and genetic effects (45.3%) were low. >50% reported poor physical and mental health. 40% were acceptive, 31.4% were unsure, and 29.7% objected to the discharge plans. Multinomial regression analysis revealed that, compared to acceptive responders, those who objected were more likely to be female, unemployed, and have anxiety about radiation-related genetic effects and poor mental health. Unsure responders were similarly more likely to be female, anxious about radiation-related genetic effects and have poor mental health. CONCLUSION: The poor mental health of the locals, connected to high levels of risk perception and anxiety about the loss of economic opportunities related to the discharge plans, must be addressed. The 30-year discharge process could handicap local industries and hamper post-disaster socioeconomic recovery due to the circulation of false rumours among consumers. These results highlight the need to actively involve residents in the towns' recovery process to address local concerns. The focus should be on the judicious combination of transparent science with the human aspect of recovery and narratives highlighting dialogues between local stakeholders and experts to enable the locals and the general public to make informed decisions about their protection and future.

Temporal variation in environmental radioactivity and radiation exposure doses in the restricted areas around the Fukushima Daiichi Nuclear Power Plant.

Temporal variation and fluctuation in environmental contamination in Futaba town and Okuma town, the location of the Fukushima Daiichi Nuclear Power Plant (FDNPP), were evaluated based on a car-borne survey conducted from October 2021 to November 2022. Although the environmental radioactivity in the interim storage facility area (ISF) was higher than that in open areas (i.e., the evacuation order lifted areas in Futaba town and the Specific Reconstruction and Regeneration Base area [SRRB] in Okuma town), only minor temporal changes were seen in the ambient dose and detection rate of radiocesium (the proportion of radiocesium detected points per all measuring points) in those areas, respectively. These findings suggest that the observed variations may result from physical decay and environmental remediation. Resuspension caused by human activities and weather could also affect the detection rate of radiocesium. The annual external effective doses in Futaba town and Okuma town were estimated to be at a limited level (< 1 mSv/year). Nevertheless, to help ensure the safety and future prosperity of residents and communities in the affected areas around the FDNPP, long-term follow-up monitoring of temporal exposure dose levels during the recovery and reconstruction phases is extremely important.

Profile of Nagasaki Islands Study (NaIS): A Population-Based Prospective Cohort Study on Multi-disease.

In an aging society, it is important to visualize the conditions of people living with diseases or disabilities, such as frailty and sarcopenia, and determine the environmental and genetic factors underlying such conditions. Atherosclerosis and arterial stiffness are key conditions between these factors and noncommunicable diseases. In 2014, we launched a population-based prospective open-cohort study, the Nagasaki Islands Study (NaIS), which was conducted in Goto City, located in the remote islands of Nagasaki Prefecture, Japan, mostly involving middle-aged and older residents. We conducted our own health checkups along with the annual standardized checkups organized by the municipality; recruited study participants; and started to follow-up with them for vital status (death), migration, and occurrence of diseases such as myocardial infarction, stroke, fracture, and human T-cell leukemia virus type 1 (HTLV-1) -associated uveitis. Our checkups were conducted as baseline surveys in different areas of Goto City during the fiscal years 2014-2016, secondary surveys during 2017-2019, and tertiary surveys since 2021, consisting of medical interviews, physical examinations, blood and urine tests, body composition measurements, osteoporosis screening, arterial stiffness measurements, carotid ultrasonography, and dental examination. A total of 4,957 residents participated in either the baseline or secondary surveys and were followed-up; and 3,594 and 3,364 residents (aged 27-96 and 28-98 years) participated in the baseline and secondary surveys, respectively. In conclusion, the NaIS has been undertaken to reveal the influence of aging and risk factors of noncommunicable diseases and disabilities, with an aim to contribute towards better healthcare in the future.

Changes in the Intention to Return and the Related Risk Perception Among Residents and Evacuees of Tomioka Town 11 Years After the Fukushima Nuclear Accident.

OBJECTIVE: This study examined temporal trends in risk perception and intention to return to Tomioka among residents and evacuees with the aim of aiding community recovery. METHODS: Responses to questionnaires distributed in 2017 and 2021 were compared regarding demographic information, intention to return to Tomioka, desire to consult radiation experts, and risk perception such as anxiety about food consumption, drinking tap water, self-health, and genetic effects. Questionnaires were distributed to all persons registered with the Tomioka town council, both current residents and evacuees. RESULTS: In 2021, the proportion of responders who had already returned/ wanted to return and those who did not want to return increased by 3.2% and 6.8% respectively, and the proportion unsure about returning decreased by 10.1%. Anxiety for self-health decreased by 15.4%, for genetic effects decreased by 24.4%, for food consumption decreased by 30.9%, and the latter 2 remained significant factors among responders unsure of returning and among those who did not want to return in 2021. CONCLUSIONS: Risk perception for food and genetic effects was significantly associated with uncertainty about returning or not returning. There is a need for continual monitoring of risk perception trends and implementation of targeted risk communication strategies.

Frequency of visits to Tomioka town and related factors among evacuees more than a decade after the Fukushima Daiichi Nuclear Power Plant accident.

This study aimed to clarify the frequency of visits (FOV) to Tomioka town, Japan, and related factors among evacuees more than a decade after the Fukushima Daiichi Nuclear Power Plant accident. A questionnaire survey was conducted on residents (age ≥ 18 years) who had residence cards in August 2021. Of the 2260 respondents, the FOV to Tomioka was as follows: 926 (41.0%) more than twice a year (Group 1 [G1]), 841 (37.2%) once a year (G2) and 493 (21.8%) no visits (G3). About 70% of the respondents who had decided not to return to Tomioka visited once a year or more. No significant differences in the FOV or radiation risk perception were found between groups. Multinomial logistic regression analysis using G3 as a reference revealed independent associations between living inside Fukushima in G1 (odds ratio [OR] = 5.4, 95% confidence interval [CI]: 4.1-7.3; P < 0.01) and G2 (OR = 2.3, 95% CI: 1.8-3.0, P < 0.01), undecided about returning in G1 (OR = 2.5, 95% CI: 1.9-3.3, P < 0.01), females in G1 (OR = 2.0, 95% CI: 1.6-2.6, P < 0.01) and motivation to learn more about tritiated water in G2 (OR = 1.8, 95% CI: 1.3-2.4, P < 0.01). Overall, 80% of the residents had visited Tomioka within a decade after the accident. These findings suggest the need to continue the effective dissemination of information about the effects of a nuclear accident and the subsequent decommissioning process to evacuees after evacuation orders have been lifted.

Comparison of quality of life between elderly and non-elderly adult residents in Okuma town, Japan, in a post-disaster setting.

With the growing elderly population who are susceptible to poor health, improvement of their quality of life is essential. In the post-disaster setting of the 2011 Fukushima Dai-ichi nuclear power plant (FDNPP) accident, affected municipalities such as Okuma town commenced their recovery processes and lifted evacuation orders in 2019. This study examines the differences in self-reported mental and physical health status, social functioning, risk perception, and intention to return between elderly (age ≥65 years) and non-elderly (age 20-64 years) residents. Questionnaires were distributed to current residents and evacuees of Okuma. Results revealed that the elderly had a 1.4 times higher odds ratio (95%CI 1.0-1.8, p = 0.034) for having anxiety regarding radiation-related health effects on future generations and a 1.3 times higher odds ratio (95%CI 1.1-1.5, p = 0.001) for wanting to know about the release of FDNPP-treated water into the environment than the younger group. Elderly residents also demonstrated a 2.2 times higher odds ratio for reporting poor physical health than younger residents. Clearing misconceptions and disseminating coherent information will reduce risk perception among this group. Further in-depth research regarding the disposal of FDNPP-treated water and its perceived risks is required. Health promotion through the encouragement of social participation, improvement of surroundings to facilitate healthy behaviors, and enhanced access to health services will improve the quality of life of elderly Okuma residents.

Assessment of Radiation Risk Perception and Interest in Tritiated Water among Returnees to and Evacuees from Tomioka Town within 20 km of the Fukushima Daiichi Nuclear Power Plant.

In this study, we aimed to investigate radiation risk perception, mental health, and interest in tritiated water among evacuees from and returnees to Tomioka town, Japan, as well as to evaluate the intention to return (ITR) among evacuees living inside and outside Fukushima Prefecture. Of the 1728 respondents, 318 (18.4%) and 1203 (69.6%) participants reported living outside and inside Fukushima Prefecture, and 207 (12.0%) reported living in Tomioka. The ITR was not significantly different between those who lived inside and outside the prefecture among the evacuees. Similarly, there were no significant differences in radiation risk perception, mental health, and interest in tritiated water. However, the evacuees were independently associated with a motivation to learn about tritiated water (OR = 1.242, 95%Cl: 1.041-1.438, p = 0.016), reluctance to consume food from Tomioka (OR = 1.635, 95%Cl: 1.372-1.948, p < 0.001), and concern that adverse health effects would occur because of the Fukushima Daiichi Nuclear Power Plant accident (OR = 1.279, 95%Cl: 1.055-1.550, p = 0.012) compared to returnees, according to logistic regression analysis. Interestingly, the returnees were found to have better mental health but lower life satisfaction than the evacuees. These findings suggest the importance of ongoing risk communication about radiation exposure and tritiated water among residents regardless of their place of residency.

Occupational Difficulties of Disaster-Affected Local Government Employees in the Long-Term Recovery Phase after the Fukushima Nuclear Accident: A Cross-Sectional Study Using Modeling Analysis.

Local government officials play a central role in post-disaster community reconstruction. However, few studies have reported on the actual difficulties during a complex disaster involving a nuclear accident. A self-rated questionnaire survey was administered to a total of 583 public employees in four municipalities around the Fukushima Daiichi Nuclear Power Station. The relationship between universal occupational factors and radiation disaster-specific factors on job satisfaction and intention to leave the job due to radiation anxiety was evaluated using structural equation modeling. The results showed that interpersonal problems (ß = -0.246) and service years (ß = -0.127) were related to job satisfaction, whereas radiation-specific factors were not related to job satisfaction, and only to the intention to leave work due to radiation anxiety. A sense of coherence was associated with job satisfaction (ß = 0.373) and intention to leave work due to radiation anxiety (ß = -0.182), and it served as a moderator of the universal occupational factors and the radiation disaster-specific factors. Therefore, it is suggested that outcomes could be improved through increased stress coping capacity by providing support for relationships and radiation risk communication to public employees during the disaster recovery period.

Assessment of localized and resuspended 137 Cs due to decontamination and demolition in the difficult-to-return zone of Tomioka town, Fukushima Prefecture.

As the next step that occurred more than one decade after the accident at the Fukushima Dai-ichi Nuclear Power Station (FDNPS), decontamination and demolition have been carried out in the Specified Reconstruction and Revitalization Base (SRRB) of the difficult-to-return zone around the FDNPS. However, the risk of internal exposure among workers due to airborne dust inhalation after building demolition operations has not been sufficiently evaluated. To evaluate the working environment and internal exposure risk due to inhalation in the SRRB of Tomioka town, Fukushima Prefecture, the cesium-137 (137 Cs) radioactivity levels in the airborne dust at building demolition sites were analyzed using gamma spectrometry. The 137 Cs radioactivity levels and resuspension factors of the airborne dust at the subject building sites in the difficult-to-return zone remained at high levels compared with those of the control, which was located in the evacuation order-lifted area in Tomioka town. However, the 137 Cs radioactivity levels did not increase significantly, despite demolition operations that used heavy machinery. In this case, no substantial increases in accident-derived 137 Cs levels due to decontamination and demolition in the SRRB of Tomioka town, Fukushima Prefecture, were observed in the airborne dust samples, which suggests that the 137 Cs radioactivity in the airborne dust is primarily associated with particles that are resuspended by localized winds accompanied by the transfer of construction vehicles as opposed to the decontamination and demolition operations. However, the internal exposure doses due to aspirating airborne dust containing 137 Cs were extremely low compared with the estimated annual effective doses of decontamination workers or the limits recommended by the Japanese government. Additionally, countermeasures such as wearing protective masks could help reduce the on-site inhalation of soil-derived radionuclides. Integr Environ Assess Manag 2022;18:1555-1563. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Evaluation of Residents' Timing of Return to or New Settlement in Kawauchi Village, at 10 Years after the Fukushima Daiichi Nuclear Power Plant Accident.

Kawauchi village in Fukushima prefecture was affected by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, and residents had to evacuate from their hometown in 2011. This study clarified the timing and related factors with regard to residents returning to or newly settling in Kawauchi. A survey was conducted using a questionnaire, from February to March 2021, with assistance from the Kawauchi village office and post office. Of the 374 residents, 170 (45.5%) had returned to or newly settled in Kawauchi within the past 2 years (group 1), 84 (22.5%) in the past 2-5 years (group 2), and 99 (26.5%) after more than 5 years (group 3) following the evacuation order. An additional 21 residents (5.5%) who had lived in Kawauchi at the time of the FDNPP had not yet returned (group 4). Compared with the other groups, residents in group 1 were more satisfied with their current lives and were coping better with stress. Even though they had experienced a serious nuclear disaster, residents of Kawauchi village who returned to their hometown in the early phase had a high sense of satisfaction with their current life one decade after the FDNPP accident.

LIFE SATISFACTION AND FACTORS AFFECTING SATISFACTION IN KAWAUCHI VILLAGE RESIDENTS AT 10 Y AFTER THE FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT.

We assessed the life satisfaction and related factors, including the mental health state, of residents of Kawauchi village, Fukushima Prefecture. Among the 374 residents who responded, 237 (63.4%) were satisfied with their current life. Of all respondents, 275 (73.5%) had a sense of belonging to the Kawauchi village community and 158 (42.2%) thought that Kawauchi had recovered after the Fukushima Daiichi Nuclear Power Station (FDNPS) accident. Regression analysis revealed that post-traumatic stress disorder checklist-Specific score, sense of belonging to the Kawauchi village community, opinion that Kawauchi village had recovered, timing of return to Kawauchi <2 y and concern about consumption of mushrooms and wild plants from Kawauchi were independently associated with life satisfaction. Although 10 y have passed since the FDNPS accident, it is necessary to continue with risk communication, particularly for new residents of Kawauchi.

Intention to Return and Perception of the Health Risk Due to Radiation Exposure Among Residents in Tomioka Town, Fukushima Prefecture, Stratified by Gender and Generation.

OBJECTIVE: The aim of this study was to clarify residents' intentions to return (ITR) to Tomioka town, Fukushima Prefecture; and their risk perception of the health effects of radiation exposure as stratified by gender and generation. METHODS: Of almost 8000 residents who were 20 years of age or older and who had lived, prior to the accident, in the zones of Tomioka town where residents were permitted to return, 1860 were included in the analysis. For the analysis, the residents were divided into 4 groups which were stratified by gender and age: older males (over 50 years), young males (20-49 years), older females (over 50 years), and young females (20-49 years). RESULTS: ITR was found to be significantly lower in young males, young females, and older females than in older males. Conversely, young and older females had significantly higher levels of anxiety about drinking tap water and consuming food collected in Tomioka town. Young and older females also had greater concerns about adverse health effects on themselves and their offspring due to living in Tomioka town. CONCLUSION: Our results showed that special attention should be paid to younger residents, particularly to young females, with regard to recovery from a nuclear disaster.

Risk Perception of Health Risks Associated with Radiation Exposure among Residents of Okuma, Fukushima Prefecture.

Ten years have passed since the Great East Japan Earthquake and the subsequent Fukushima Daiichi nuclear power plant accident on 11 March 2011. Okuma is a town hosting the Fukushima Daiichi nuclear power plant. The evacuation order for Okuma was partially lifted in April 2019. To clarify factors associated with risk perceptions of radiation among the residents of Okuma, we conducted a questionnaire survey in January 2021. Our results revealed that resident anxieties regarding the health effects of radiation exposure from living in Okuma were independently associated with positive PCL-Specific score, recognition of the consultation services with radiation experts in the municipal government of Okuma, and planned request for consultation service regarding radiation exposure by radiation experts, along with being female and living with a child. It is important for radiation experts to promote periodic communication of risks with individuals on a small scale to provide accurate information about the health effects of radiation and to provide maternal and child healthcare services and support regarding child-rearing and radiation exposure, to reduce concerns about radiation exposure and facilitate healthy living and wellbeing in Okuma.