Errata: Internal doses from radionuclides and their health effects following the Fukushima accident (J. Radiol. Prot. 2018 38 1253-68).

This article presents errata on a published article.

Internal doses from radionuclides and their health effects following the Fukushima accident.

This paper presents an overview of current internal dose estimates from the Fukushima accident, potential population specific uncertainties in these estimates are investigated, along with the relative effects of internal and external exposures. Thyroid doses were largely due to 131I, but variations in thyroid weight and fractional uptake and retention times of 131I in the thyroid contribute to uncertainties in thyroid dose estimates. Lower values for these parameters in the Japanese population, as compared to international reference assumptions, would lead to underestimation of doses on the basis of reference thyroid weights and overestimation of doses using reference thyroid uptake and retention times. Any overall bias in thyroidal doses due to population specific factors is the net result of the balance between these effects. Internal doses to other organs are largely due to 134Cs and 137Cs and their whole body distribution, population specific differences in these dose estimates are driven by average body mass, due to the inverse relationship between this and retention times. Potential differences in dose estimates and any inferred risks, due to local population specific factors, may be less than a factor of two for children and male adults, but the potential difference may be slightly underestimated for female adults. Recent micro-dosimetric studies have confirmed the existing perception that risk from internal exposures to 137Cs, 134Cs, and 131I should be nearly equivalent to that from external exposure to gamma rays at the same absorbed dose. Epidemiological studies provide comparisons between external and internal exposures to 131I in children and suggest that effects of internal exposure are similar to those of external exposure. Effective dose has been formulated to harmonise internal and external exposure risks for radiation protection purposes. On the basis of this review, the use of effective dose in this context does not seem to be unreasonable.

Radioactive cesium (¹³4Cs and ¹³7Cs) content in human placenta after the Fukushima nuclear power plant accident.

AIM: The degree of contamination with radioactive cesium (¹³4Cs and ¹³7Cs) in the human placenta after the accident at Fukushima nuclear power plant (FNP), which occurred on 11 March 2011, has not been assessed. MATERIAL AND METHODS: ¹³4Cs and ¹³7Cs contents were determined in 10 placentas from 10 women who gave birth to term singleton infants during the period between October 2011 and August 2012 using high-purity germanium detectors for gamma ray spectrometry. Five women resided within 50 km of FNP (neighbor group) and gave birth by the end of February 2012, while the other five women resided within 210-290 km of FNP (distant group) and gave birth in July and August 2012. RESULTS: All except one of the 10 placentas contained detectable levels of ¹³4Cs and ¹³7Cs, ranging 0.042-0.742 Bq/kg for ¹³4Cs and 0.078-0.922 Bq/kg for ¹³7Cs. One placenta from a woman living in Tokyo contained 0.109 Bq/kg ¹³7Cs and no detectable level of ¹³4Cs (<0.054 Bq/kg). ¹³7Cs content was more than 0.2 Bq/kg in four and one placentas in the neighbor and distant groups, respectively. CONCLUSION: Degree of contamination of the placenta with radioactive Cs was lower even in women who resided within 50 km of FNP compared to Japanese and Canadian placentas in the mid-1960s after repeated nuclear tests and in northern Italian placentas from 1986-1987 after the Chernobyl power plant accident.

Smoking topography and biomarkers of exposure among Japanese smokers: associations with cigarette emissions obtained using machine smoking protocols.

OBJECTIVES: Although the relative risk of lung cancer due to smoking is reported to be lower in Japan than in other countries, few studies have examined the characteristics of Japanese cigarettes or potential differences in smoking patterns among Japanese smokers. METHODS: To examine tar, nicotine and carbon monoxide (TNCO) emissions from ten leading cigarettes in Japan, machine smoking tests were conducted using the International Organization for Standardization (ISO) protocol and the Health Canada Intense (HCI) protocol. Smoking topography and tobacco-related biomarkers were collected from 101 Japanese smokers to examine measures of exposure. RESULTS: The findings indicate considerable variability in the smoking behavior of Japanese smokers. On average, puffing behaviors observed among smokers were more similar to the parameters of the HCI protocol, and brands with greater ventilation that yielded lower machine values using the ISO protocol were smoked more intensely than brands with lower levels of ventilation. The smokers of "ultra-low/low" nicotine-yield cigarettes smoked 2.7-fold more intensively than those of "medium/high" nicotine-yield cigarette smokers to achieve the same level of salivary cotinine (p = 0.024). CO levels in expiratory breath samples were associated with puff volume and self-reported smoking intensity, but not with nominal values of nicotine-yield reported on cigarette packages. CONCLUSIONS: Japanese smokers engaged in "compensatory smoking" to achieve their desired nicotine intake, and levels of exposure were greater than those suggested by the nominal value of nicotine and tar yields reported on cigarette packages.

[Current status on storage, processing and risk communication of medical radioactive waste in Japan].

Decay-in-storage for radioactive waste including that of nuclear medicine has not been implemented in Japan. Therefore, all medical radioactive waste is collected and stored at the Japan Radioisotope Association Takizawa laboratory, even if the radioactivity has already decayed out. To clarify the current situation between Takizawa village and Takizawa laboratory, we investigated the radiation management status and risk communication activities at the laboratory via a questionnaire and site visiting survey in June 2010. Takizawa laboratory continues to maintain an interactive relationship with local residents. As a result, Takizawa village permitted the acceptance of new medical radioactive waste containing Sr-89 and Y-90. However, the village did not accept any non-medical radioactive waste such as waste from research laboratories. To implement decay-in-storage in Japan, it is important to obtain agreement with all stakeholders. We must continue to exert sincere efforts to acquire the trust of all stakeholders.

[Evaluation of a risk communication approach for maintenance staff working with induced radioactivity in medical linear accelerators].

In order to promote consensus building on decommissioning operation rules for medical linear accelerators in Japan, we carried out a risk communication (RC) approach mainly providing knowledge for maintenance staff regarding induced radioactivity. In February 2012, we created a booklet (26 pages) to present an overview of the amended law, the mechanism and the distribution of induced radioactivity showing the actual radiation dose rate around a linear accelerator and actual exposure doses to staff. In addition, we co-sponsored a seminar for workers in this field organized by the Japan Medical Imaging and Radiological Systems Industries Association to explain the contents of this booklet, and answer questions regarding induced radioactivity of linear accelerators as an RC program. As a result, the understanding of staff regarding the regulations on maximum X-ray energy on linear accelerators (P<0.05), and the outline of clearance systems (P<0.01), were facilitated by RC. In addition, we found that about 70% of maintenance staff considered that the cooling time for decommissioning operation depended on the situation. Our RC approach suggests that consensus building should be used to make rules on decommissioning operations for linear medical accelerators.

Public Health Centers' Training Session Programs to Develop Programs on Infection Control Practices for Multidrug-Resistant Organisms in Hospitals in Kawaguchi City, Japan.

Introduction The Kawaguchi City Public Health Center (PHC) conducted training sessions focusing on infection control practices on multidrug-resistant organisms (MDROs) for 19 hospitals and eight affiliated clinics (AFs) with beds in June 2022. Issues with infection control programs were identified via a survey implemented following the training sessions. These included providing feedback on infection control policies for MDROs, hand hygiene compliance programs (HHCPs), environmental cleaning (EC), and training sessions programs that hospitals or AFs with beds (hospitals) intended to implement in the future or develop (to be developed). We planned to examine whether the PHC training sessions programs have an effect on the development of hospital infection control programs designed to address these issues. The purpose of this study is to clarify the training session program provided by the Kawaguchi City PHC, which was effective in developing hospital infection control programs based on the results of the survey conducted after the training session. Methods In June 2023, a second training session that offered information on infection control practices was completed for 30 hospitals. This was followed by sending a questionnaire. We examined infection control programs to be developed and analyzed associations with the first learned information by training session (the first learned information). Results Twenty-four hospitals responded to the survey with a response rate of 80.0%. Half the respondents (12, 50.0%) had prepared for the infection control policy on carbapenem-resistant Enterobacteriaceae (CRE), 11 hospitals (45.8%) had provided feedback on HHC, and four (16.7%) planned to conduct feedback on HHC. HHCPs were planned to be developed by 19 hospitals (79.2%), EC by five hospitals (20.8%), training session by 12 hospitals (50.0%), and screening of MDROs upon hospital admission (AS) by nine hospitals (37.5%). The first learned information, "the prevention of healthcare-associated infections and cost savings by implementing cleaning bundles (the effects of cleaning bundles)," was identified by 10 hospitals (41.7%), and "specific programs on providing feedback effective for developing hand hygiene compliance (specific feedback)" was learned by eight hospitals (33.3%). The first learned information regarding specific feedback was significantly associated with HHCPs to be developed (p = 0.044). The first learned information on the effects of cleaning bundles was significantly associated with HHCPs and HHC feedback to be developed (p = 0.023, 0.034). The training session programs were not significantly connected to EC, training session, or AS to be developed. Conclusions Infection control programs to be developed were linked to the provision of information on numerical effects by implementing specific feedback and cleaning bundles. We suggest that the PHC should develop infection control programs for the hospitals and provide training sessions, including numerical effects.

Targeted Infection Control Practices in Japanese Hospitals for Multidrug-Resistant Organisms: Guidance From the Public Health Center.

Introduction The study conducted by the Kawaguchi City Public Health Center (PHC) in 2023 on hospital infection control (IC) programs revealed that hospitals can improve their IC programs if the PHC provides training sessions (TSs) that have numerical effects. In this study, we expected that we could help hospitals develop their IC practices by providing targeted guidance. This study aimed to clarify targeted guidance on IC practices and TS programs to develop hospitals'hospitals' IC programs on multidrug-resistant organisms (MDROs) by examining hospitals'hospitals' IC programs in reference to the study conducted in 2023 and other case reports. Methods In June 2022, the Kawaguchi City PHC conducted TSs for 19 hospitals and eight affiliated (AFs) clinics with beds, providing guidelines and practices on infection control (IC) for MDROs. After the TSs, we sent a questionnaire to these hospitals and affiliated clinics. The questionnaire inquired about current and planned IC policies, hand hygiene compliance programs (HHCPs), the usefulness of the TSs conducted by the PHC, and IC programs that the facilities intended to implement or develop in the future. This study examined the relationship between the perceived usefulness of the information provided and the IC programs planned for development, referencing a study conducted in 2023 and other case reports. Results Seventeen hospitals and six AFs with beds responded to the survey, yielding an 85.2% response rate. IC policies for methicillin-resistant Staphylococcus aureus (MRSA) were prepared by 21 hospitals (91.3%), whereas only five hospitals (21.7%) had prepared IC policies for carbapenem-resistant Enterobacteriaceae. Regarding HHCPs, an increase in the availability of alcohol-based hand sanitizer was identified by 17 hospitals (73.9%), while 13 hospitals (56.5%) reported using posters or symbols, 12 hospitals (52.2%) reported using TS and hand sanitizers, and nine hospitals (39.1%) assessed HH compliance and provided feedback. Furthermore, nine hospitals (39.1%) identified HHCPs and Environmental Cleaning (EC) for carbapenemase-producing Enterobacteriaceae (CPE) as useful information. There was a statistically significant association between TSs on HHCPs and the development of new HHCPs (p = 0.027). Additionally, information on EC for CPE was significantly associated with the development of staff cohorting strategies (p = 0.007). However, TS programs were not significantly connected to EC, nor were TSs to be developed. Conclusion The PHC should advise hospitals to assess if their HHCPs effectively contribute to improving HH compliance. It is essential for the PHC to furnish hospitals with resources and information that aid in the development of EC training. Additionally, the PHC should support the creation of specific and effective TS programs focused on EC or TS development. Conducting surveys to identify barriers to implementing staff cohorting strategies is also recommended. We propose that TS programs should include quantifiable data on HHCPs and EC, such as.

Long-Term Analysis of Internal Exposure Dose-Reduction Effects by Food Regulation and Food Item Contribution to Dose after the Fukushima Daiichi Nuclear Power Plant Accident.

Over 10 years have passed since the Fukushima Daiichi Nuclear Power Plant accident. This study verifies the efficacy of longitudinal regulation on internal exposure doses and analyzes food group contributions to radiation doses using accumulated monitoring test results. The committed effective doses in 10,000 virtual persons from fiscal year (FY) 2012 to 2021, with and without regulation, were estimated as products of radioactivity concentrations randomly sampled from the test results, food intake, and dose coefficient. The distributed values of food intake rather than a mean value in dose estimation were assumed to reflect food intake variations and avoid underestimation of internal exposure doses for high-intake consumers. Furthermore, the ingestion of radioactive cesium from the calculation was analyzed per food group. The 95th percentile of the internal exposure dose (the dose of a "representative person") was less than 1 mSv/year in both FYs. The regulation effect was substantial in FY 2012, and no noticeable difference in radiation doses was found between the regulation and no regulation conditions after FY 2016. Internal exposure doses decreased until approximately FY 2016 and then remained constant. It was also shown that not only radioactivity concentration but also food intake is a major factor affecting cesium intake. In summary, it was confirmed that Japan had ensured food safety regarding radioactive materials.

Interlaboratory comparison of electron paramagnetic resonance tooth enamel dosimetry with investigations of the dose responses of the standard samples.

A total of seven Japanese laboratories participated in an intercomparison study to estimate the dose given to tooth enamel samples, using the electron spin resonance method. Each of four of the participating laboratories prepared a set of tooth enamel samples, using the electron spin resonance method. Four of the participating laboratories each prepared a set of tooth enamel samples, consisting of seven standard aliquots irradiated from 100 to 2000 mGy and three samples with an 'unknown' dose between 140 and 960 mGy, were intended to eliminate bias from sample preparation. Although not all seven laboratories measured all four sets of samples, the major finding was that systematic biases in estimating doses may be caused by differences in laboratory measurements rather than by the enamel extracting procedures. When doses were averaged by measurements made by multiple laboratories, the averaged values were close to the actual values. Scattering in the intercepts in the standard dose response would be a serious problem in actual dosimetry where no background sample is available.

Effect of the Fukushima nuclear power plant accident on radioiodine (¹³¹ I) content in human breast milk.

BACKGROUND: Environmental pollution with radioiodine (iodine-131, (131) I) occurred after an accident at the Fukushima nuclear power plant (FNP) on March 11, 2011, in Japan. Whether environmental pollution with (131) I can contaminate human breast milk has not been documented. METHODS: The (131) I content was determined in 126 breast milk samples from 119 volunteer lactating women residing within 250 km of the FNP, between April 24 and May 31, 2011. The degree of environmental pollution was determined based on the data released by the Japanese government. RESULTS: An (131) I content of 210 Bq/kg in the tap water in Tokyo, which is located 230 km south of the FNP, on March 22 and of 3500 Bq/kg in spinach sampled in a city located 140 km southwest of the FNP on March 19 decreased over time to <21 Bq/kg on March 27 and 12 Bq/kg on April 26, respectively. Seven of the 23 women who were tested in April secreted a detectable level of (131) I in their breast milk. The concentrations of (131) I in the breast milk of the seven women were 2.3 Bq/kg (on April 24), and 2.2, 2.3, 2.3, 3.0, 3.5 and 8.0 (on April 25); the concentrations of (131) I in the tap water available for these seven women at the same time were estimated to be <1.3 Bq/kg. None of the remaining 96 women tested in May exhibited a detectable concentration of (131) I in their breast milk samples. CONCLUSIONS: The contamination of breast milk with (131) I can occur even when only mild environmental (131) I pollution is present.

Clinical impact of patient-centered care for hemodialysis patients using routine assessment of symptom burden.

The study aimed to verify the impact of our clinical strategy, which emphasizes patient-centered care, based on patient-reported outcome measures (PROMs) results in hemodialysis patients. We developed our original PROM (comprising 20 items) to assess patients' symptom burden. To confirm the validity of our clinical pattern, we performed various analyses using PROM data. We retrospectively enrolled 383 individuals (mean age 66.3 years; 252 men), collected their PROM data in December 2013, and followed them up for 3 years. We noted a lower mortality rate and a lower prevalence of itching in our facilities than in previous surveys and reports in Japan. Furthermore, we observed that the severity of symptom burden affected medium-term prognosis. This is the first study to report the results of patient-centered medical practice utilizing PROMs in dialysis care. Careful attention should be paid to patients' symptom burden, as performed in objective data management.

Longitudinal Verification of Post-Nuclear Accident Food Regulations in Japan Focusing on Wild Vegetables.

Focusing on the importance of wild vegetables for local residents, this study aims to validate the effects of food regulations under the current criteria (e.g., 100 Bq/kg for general foods) established approximately a year after the Fukushima Dai-ichi Nuclear Power Plant accident. Over 2,500,000 monitoring tests were performed under the criteria until fiscal year (FY) 2020. We estimated changes in internal exposure dose using test results. The effective dose was estimated using the radioactive concentration randomly sampled from the results, food intake, and dose conversion factor. As a new attempt, dose estimation reflecting the intake of wild vegetables that may have irreplaceable value for local residents was conducted. The median, 95th, and 99th percentile of the estimated dose without reflecting the wild vegetables' intake were 0.0485, 0.183, and 10.6 mSv/year, respectively, in the estimation with all test results (no regulation) and 0.0431, 0.0786, and 0.236 mSv/year, respectively, in the estimation with results within the standard limits (regulated) in FY2012. These doses decreased with time. Although estimated doses with or without the reflection of wild vegetables' intake were similar, estimation that is more plausible is possible, particularly for a high percentile, by reflecting the wild vegetables' intake. Radiation doses (regulated) were significantly less than 1 mSv/year in different FYs. In Japan, food regulation measures benefit food safety.

Estimation of Effect of Radiation Dose Reduction for Internal Exposure by Food Regulations under the Current Criteria for Radionuclides in Foodstuff in Japan Using Monitoring Results.

This study examined the effect of food regulations under the current criteria (e.g., 100 Bq/kg for general foods) established approximately a year after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Foods are monitored to ensure that foods exceeding the standard limit are not distributed; ~300,000 examinations per year have been performed especially since FY2014. This study comprehensively estimated the internal exposure dose resulting from the ingestion of foods containing radioactive cesium using the accumulated monitoring results. Committed effective dose was conservatively calculated as the product of the radioactive concentration randomly sampled from test results, food intake, and dose coefficient. The median, 95th, and 99th percentile of the dose were 0.0479, 0.207, and 10.6 mSv/y, respectively, in the estimation with all test results (without regulation), and 0.0430, 0.0790, and 0.233 mSv/y, respectively, in the estimation with results within the standard limits (with regulation) in FY2012. In FY2016, the dose with and without regulation were similar, except for high percentile, and those doses were significantly smaller than 1 mSv/y, which was adopted as the basis for the current criteria. The food regulation measures implemented in Japan after the FDNPP accident have been beneficial, and food safety against radionuclides has been ensured.

Effective dose during abdominal three-dimensional imaging with a flat-panel detector angiography system.

The purpose of this study was to measure the effective dose during abdominal three-dimensional imaging obtained with an angiography unit with a digital flat-panel system on a phantom and to determine dose-area product (DAP)-to-effective dose conversion factors. DAPs and effective doses were evaluated for 163-cm-tall human-shaped phantoms with estimated body weights of 54, 64, and 77 kg, and the effective doses were 2.1, 3.2, and 4.2 mSv, respectively. The DAP-to-effective dose conversion factors were 0.28-0.29 mSv x Gy(-1) x cm(-2). In conclusion, the DAPs were useful for estimating the effective dose during abdominal three-dimensional angiographic imaging.

[Investigation of actual condition of management and disposal of medical radioactive waste in Korea].

In order to realize the rational management and disposal of radioactive waste like DIS or its clearance as performed in Europe, North America, and Japan, we investigated the situation of medical radioactive waste in Korea and its enforcement. We visited three major Korean facilities in May 2008 and confirmed details of the procedure being used by administering a questionnaire after our visit. From the results, we were able to verify that the governmental agency had established regulations for the clearance of radioactive waste as self-disposal based on the clearance level of IAEA in Korea and that the medical facilities performed suitable management and disposal of radioactive waste based on the regulations and superintendence of a radiation safety officer. The type of nuclear medicine was almost the same as that in Japan, and the half-life of all radiopharmaceuticals was 60 days or less. While performing regulatory adjustment concerning the rational management and disposal of radioactive waste in Korea for reference also in this country, it is important to provide an enforcement procedure with quality assurance in the regulations.

[Nationwide survey on radioactive waste management related to positron emission tomography in Japan].

BACKGROUND AND PURPOSE: A clearance system for medical radioactive solid waste has not yet been implemented in Japan. Since 2004 new regulations have allowed institutions using positron emission tomography(PET)to handle totally decayed radioactive waste as non-radioactive waste after decay-in-storage. It was expected that this new regulation would mediate the installation of clearance systems in Japan. In order to assess the current situation of radiation safety management in PET institutions, we conducted a nationwide survey. METHODS: The study design was a cross-sectional descriptive study conducted by questionnaire. The subjects of this survey were all the PET institutions in Japan. Among 224 institutes, 128 institutes are equipped with cyclotrons and 96 institutes are not. The number of returned questionnaires was 138. RESULT: Among institutes that are using delivered radiopharmaceuticals, 80% treat their waste as non-radioactive according to the new regulation. The impact of new regulations for reducing radioactive waste in PET institutes without a cyclotron was estimated at about $400 thousand per year. DISCUSSION: The main concern of medical institutes was assessment of the contamination caused by by-products of radioactive nuclides generated in target water during the operation of a cyclotron. It was thought that a rational rule based on scientific risk management should be established because these by-products of radioactive nuclides are negligible for radiation safety. CONCLUSION: New regulation has had a good influence on medical PET institutes, and it is expected that a clearance system for medical radioactive waste will be introduced in the near future, following these recent experiences in PET institutes.

Entrance surface dose during three-dimensional imaging with a flat-panel detector angiography system.

PURPOSE: To measure the entrance surface dose (ESD) during three-dimensional (3D) imaging of a phantom and evaluate a method to estimate ESD with use of dose-area product (DAP) values. MATERIALS AND METHODS: The present study used an angiographic unit with a digital flat-panel system for 3D imaging. DAP values and ESDs were evaluated on square phantoms with thicknesses of 12.0, 15.0, 18.0, 21.0, and 25.0 cm with use of 5-second acquisitions. ESDs were measured on the lateral and posterior surfaces of the square phantom. DAP values and ESDs were also evaluated on a human-shaped phantom with various table heights, with ESDs measured on the phantom surfaces on the posterior centerline, right middle axillary line, and their midpoint. RESULTS: The posterior ESDs were 7.3 mGy, 12.1 mGy, 18.8 mGy, 26.9 mGy, and 38.5 mGy for the square phantoms with thicknesses of 12 cm, 15 cm, 18 cm, 21 cm, and 25 cm, respectively. The DAP and the posterior ESDs were correlated (r = 0.998, P < .0001). The regression equation was D = DAP x 0.0014, where D was the posterior ESD (mGy). For the human-shaped phantom, the posterolateral ESD tended to be slightly larger than the posteromedial ESD, with the differences less than 10%. The estimated doses based on this relationship were almost equal to the actual posterolateral doses for each table height. CONCLUSIONS: The ESD of a single 3D imaging study was considerably lower than the thresholds for radiation skin injuries. The DAP values are useful to estimate the maximum patient ESD during 3D imaging.