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Seven emergency nuclear workers, who had internal exposure due to an intake of radionuclides, mainly I-131, during the emergency response operation in March 2011, after the accident at the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant (FDNPP), visited the National Institute of Radiological Sciences (NIRS) outpatient clinic for medical evaluation. They were followed up after their first visit for 10 years. The estimated committed equivalent doses to the thyroid were distributed between 3.2 to 1.2 × 10 Sv. This group thought to be received highest exposure at the accident. None of the workers had symptoms related to abnormal thyroid function. The examinations, including thyroid function tests and ultrasound, detected no abnormalities related to radiation exposure. However, there is a need for continuous monitoring of their thyroid status for longer periods in the future.

Background: In Japan, new regulations that revise the dose limit for the lens of the eye (hereafter the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulation Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens.Materials and Methods: The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set not to exceed the dose limit for the lens.Results and Discussion: In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 examples. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed.Conclusion: With the development of the guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimize radiation protection.

Background In Japan, new regulations that revise the dose limit for the lens of the eye (hereafter the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulation Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens. Materials and Methods The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set not to exceed the dose limit for the lens. Results and Discussion In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 examples. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed. Conclusion With the development of the guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimize radiation protection. Keywords: New Dose Limit to the Lens of the Eye, Monitoring Guideline, Operational Quantities, Management Criteria, Non-uniform Exposure, Japan Health Physics Society

被ばく医療に必要な資機材のリスト

原子力災害医療における国内機関の体制と運用について解説した

被ばく患者診療に関してのマニュアル的文書となる「被ばく医療診療手引き」の編集作業

前駆症状による線量評価と診断、特に嘔吐の時間などについて、解説した。

患者搬送の場合分けと注意点について解説した。

内部被ばくの治療法について、一般的治療法と薬剤（除去剤）による治療について解説した。

手引きの経緯、目的、概要について解説した。

The dose reconstruction of populations potentially affected by the accident at the Fukushima Daiichi Nuclear Power Plant in March 2011 is of great importance. However, it has been difficult to assess thyroid internal doses of Fukushima residents mainly from their intake of 131I due to the lack of direct measurements. Only about 1,300 data of the residents related to 131I have been available, and 1,080 of the data were obtained from the screening campaign that was conducted by the Nuclear Emergency Response Local Headquarter at the end of March 2011 in Kawamata-town, Iwaki-city, and Iitate-village. Here, we reassessed the thyroid doses of the 1,080 subjects aged  15-y-old by using new age-specific conversion factors to determine the 131I thyroid contents from net signals of the devices used, with consideration of the possible uncertainty related to the measurements. The results demonstrated that the thyroid equivalent doses of the subjects were < 30 mSv (excluding outliers). We also demonstrate the dose distributions of each age group from the above three municipalities and those of subjects from Minamisoma-city and Fukushima-city. One of the findings was that the 131I intake was similar among different age groups in each of the three municipalities. This was consistent with the assumption that ingestion was a dominant route of intake rather than inhalation. The range of thyroid doses for Iitate-village were similar to that for Iwaki-city even though the 131I concentration in tap water was much higher in Iitate-village than Iwaki-city. The range of thyroid doses for Minamisoma-city was similar to those for Iitate-village and Iwaki-city, and the range for Fukushima-city was smallest among the five municipalities. Since the major route of intake has remained unclear, this paper presented the plausible upper and lower thyroid doses, between which the actual doses are thought to exist mostly, based on the two intake scenarios: single inhalation and repeated ingestion. Further research is thus necessary to extract useful evidence from the individual evacuation behaviors for improving the present thyroid internal dose assessment.

In Japan, the radiation-dose limit for the lens of the eye was revised in April 2021. Consequently, for workers, the numerical values of the equivalent dose to the lens of the eye are equal to those of the effective dose. Radiation workers, radiation safety officers and licensees must comply with regulations related to radiation protection and optimize protection. The new guidelines on dose monitoring of the lens of the eye developed by the Japan Health Physics Society recommend for the dose to be estimated near the eye for accurate estimation, when the dose to the lens approaches or exceeds the management criteria. However, there is limited information regarding the non-uniform exposure of nuclear power plant workers. In this study, the dose equivalents of high-dose-rate workplaces and the personal doses of 88 workers were estimated at four Japanese commercial nuclear power plant sites (RWR: 3 units and BWR: 3 units) and the dose to the lens of the eye and the exposure situations of the workers were analyzed.

As a response to the Tokyo Electric Power Company's Fukushima Daiichi nuclear power plant accident in 2011, seven TEPCO workers whose exposure doses were expected to be >250 mSv (a tentative dose limit stipulated by the Japanese central authority) attended Japan's National Institute for Radiological Sciences for additional internal dose measurements. The National Institute for Radiological Sciences examination revealed that these workers' internal doses came mainly from their intake of the radionuclide I during emergency operations. In this study, we performed numerical simulations based on individual volume-pixel (voxel) phantoms of six of the seven workers for a more sophisticated evaluation of their internal doses, taking into account the individual thyroid size and other specific parameters. The voxel phantoms were created from magnetic resonance imaging scan images. As a result, the individual thyroid volumes ranged from 6.5 to 28.2 cm and were considerably smaller than the reference value (~20 cm) adopted in the International Commission on Radiation Protection's dosimetric model for four of the six subjects. Compared to the original estimates of the thyroid absorbed dose, our preliminary evaluation revealed values that were increased by approximately 3-fold or decreased by 30% at maximum. A wide difference in the individual thyroid size would be one of the significant modifiers in the current dose estimation of subjects of the ongoing epidemiological study project. The present simulations also provided evidence that the direct thyroid measurements by the National Institute for Radiological Sciences to determine the workers' I thyroid contents were sufficiently accurate.

Changes in Japanese system for radiation emergency after TEPCO Fukushima NPP accident are presented. Recent change introducing the core advanced radiation emergency medical support center is underlined., The 16th Coordination meeting of WHO REMPAN members

The 5th QST International Symposium on Radiation Emergency Monitoring and Medicine in Nuclear Disasterを2021年9月に開催したことの紹介。

Since the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens of the eye in 2011, there have been extensive discussions in various countries. This paper reviews the current situation in radiation protection of the ocular lens and the discussions on the potential impact of the new lens dose limit in Japan. Topics include historical changes to the lens dose limit, the current situation with occupational lens exposures (e.g., in medical workers, nuclear workers, and Fukushima nuclear power plant workers) and measurements, and the current status of biological studies and epidemiological studies on radiation cataracts. Our focus is on the situation in Japan, but we believe such information sharing will be useful in many other countries.

The dose reconstruction of populations potentially affected by the accident at the Fukushima Daiichi nuclear power plant in March 2011 is of great importance. However, it has been difficult to assess internal thyroid doses to Fukushima residents (mainly from their intake of I) due to the lack of direct measurements. For the residents, only about 1,300 data points related to I are available, and 1,080 of the data points were obtained from the screening campaign that was conducted by the Nuclear Emergency Response Local Headquarters at the end of March 2011 in Kawamata Town, Iwaki City, and Iitate Village. Here, we reassessed thyroid doses to 1,080 subjects aged ≤15 y old using new age-specific conversion factors to determine I thyroid contents from net signals of the devices used, with consideration for the possible uncertainty related to the measurements. The results demonstrated that thyroid equivalent doses to the subjects were

In Japan, the possibility to change the current dose limit of the lens of the eye for the radiation workers working in the planned exposure situation (normal controlled situations) to a new ICRP dose limit was discussed. It was further discussed how to appropriately monitor and manage the equivalent dose of the eye lenses for these workers exposed to radiation at their workplaces, such as nuclear and medical facilities. Among the workers exposed to a high-dose radiation at the water storage flange tank deconstructed 90Sr/90Y dominant areas and the nuclear reactor buildings (high dose gamma-ray) of the Fukushima Daiichi Nuclear Power Plant (1F-NPP), Hp(10), Hp(3), and Hp(0.07) at the head and the chest (or the upper arm) were estimated by passive personal dosimeters using thermoluminescence dosimeters (TLDs) and radio photoluminescence glass dosimeters (RPLGDs). The relationship between Hp(10), Hp(3), and Hp(0.07) along with the effects of the sites of wearing dosimeters on the head inside a full-face mask and the chest (or upper arm) were discussed.

This article introduces the first accident of internal contamination with plutonium (Pu) or americium (Am) in Japan for which treatment was carried out. An accident of internal contamination with Pu and Am occurred at a Pu research facility at Oarai-town of Ibaraki prefecture in Japan. A plastic bag containing these radionuclides ruptured when five workers were inspecting a storage container in a hood. As a consequence, these workers were internally contaminated with Pu and Am. Although contamination on the body surface was observed in all five workers, a positive nasal swab was detected in only three of them. A chelating agent, calcium diethylenetriaminepenta-acetate (CaDTPA), was administered to all of them including the two workers without a positive nasal swab. However, bioassay detected a significant amount of Pu and Am in urine after administration of DTPA in these two workers, whereas the levels of these nuclides were below minimum detectable levels in urine before the administration. Since the prevalence of adverse reactions in DTPAs is low, the present results suggest that administration of DTPA can be used for the diagnosis of internal contamination even when a nasal swab is negative or contamination around body orifices is not detected.

In the aftermath of the 2011 Fukushima nuclear disaster, a screening survey for thyroid internal exposure from intake of radioiodine was performed on 1080 children using handheld NaI(Tl) survey meters. This article presents the design and results of a practical exercise conducted to develop the skills of personnel who would be potentially engaged in such a survey. Participants of this exercise were asked to measure manikin heads in which point sources were installed under normal (~0.05 μSv h−1) and elevated (~0.5 μSv h−1) background conditions. The results demonstrated that the measurements were less dependent on the background radiation level, and the deviation of net signals obtained by the participants were within 10–20% for dose rates above 0.2 μSv h−1. This result suggests that dose rates can be reliably obtained above a provisional operational intervention level for the device, 0.5 μSv h−1 under a real nuclear accident situation.

A huge earthquake struck the northeast coast of the main island of Japan on March 11, 2011, triggering a tsunami with 14–15 meter-high waves hitting the area. The earthquake was followed by numerous sustained aftershocks. The earthquake affected the nuclear power plant (NPP) in Fukushima prefecture, resulting in large amounts of radioactive materials being released into the environment. The major nuclides released on land were 131I, 134Cs, and 137Cs. Therefore, almost 170 000 people had to be evacuated or stay indoors. Besides the NPP and the telecommunications system, the earthquake also affected infrastructures such as the supplies of water and electricity as well as the radiation monitoring system. The local hospital system was dysfunctional; hospitals designated as radiation-emergency facilities were not able to function because of damage from the earthquake and tsunami, and some of them were located within a 20 km radius of the NPP, the designated evacuation zone. Local fire department personnel were also asked to evacuate. Furthermore, the affected hospitals had not established their evacuation plans at that time. We have learned from this “combined disaster” that the potential for damage to lifelines as well as the monitoring systems for radiation in case of an earthquake requires our intense focus and vigilance, and that hospitals need comprehensive plans for evacuation, including patients requiring life support equipment during and after a nuclear disaster. There is an urgent need for a “combined disaster” strategy, and this should be emphasized in current disaster planning and response.

On 11 March 2011, the Great Eastern Japan Earthquake occurred, causing the accident at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Co. Residents were surveyed for contamination, and hospitalized patients within a 30-km area were transferred. In this report, the authors review the results of the survey and the effects. The screening teams measured total body contamination of each person using a Geiger-Mueller survey meter. Decontamination level was set at 100 kcpm (100,000 cpm). For levels of 13 to100 kcpm, decontamination by wiping was planned and took place. Contamination screening during 11-21 March 2011, was carried out for 72,660 people at 200 sites. From 12 March 2011 until 10 February 2012, a total of 244,281 people were screened. As a result, there were 110 cases exceeding 100 kcpm, and 901 cases with contamination levels of 13-100 kcpm. The number of contaminated individuals screened reached a peak from 16-18 March. In the accident, contamination screening of victims and residents was performed to deal with anxiety and discrimination toward the residents. Although there was some early delay, almost all of the evacuees were relatively promptly screened. There was no external contamination at levels thought to affect the health of residents. In addition, the detection of contamination levels over 13 kcpm peaked between 15-22 March. Considering factors such as the evacuation period, this suggests that even if iodine tablets had been administered during this time, they would not have been effective.

Summary Background Several large randomised studies from western Europe and the USA have shown that accelerated fractionation of radiotherapy might be beneficial in the treatment of squamous-cell carcinoma of the head and neck (HNSCC). The aim of this study—the International Atomic Energy Agency (IAEA) ACC trial—was to determine whether accelerated fractionation could be applied in developing countries, where there are fewer therapeutic resources and where tumour burdens can be heavier. Methods Between Jan 6, 1999, to March 31, 2004, nine centres from Asia, Europe, the Middle East, Africa, and South America recruited patients with HNSCC of the larynx, pharynx, and oral cavity who were eligible for curative radiotherapy. Patients were randomly assigned in this open-label trial to receive an accelerated regimen of six fractions of radiotherapy per week (n=458) or to receive a conventional radiotherapy regimen of five fractions per week (n=450), receiving a total dose of 66–70 Gy in 33–35 fractions. Patients were stratified by tumour localisation, T classification, histopathological grade, and institution. Randomisation was done by a central computer-generated balanced randomisation algorithm. The primary endpoint was locoregional control, analysed for all eligible patients, irrespective of whether or not they had completed the course of radiotherapy. This trial is registered with ClinicalTrials.gov, number NCT00120211. Findings Six patients in the accelerated group and two in the conventional group were excluded from analyses because of withdrawal of consent or missing data. The planned total radiotherapy dose was received by 418 (92%) of the 452 eligible patients in the accelerated radiotherapy group and 413 (92%) of the 448 patients in the conventional radiotherapy group. Median treatment time was 40 days in the accelerated group and 47 days in the conventional group. The 5-year actuarial rate of locoregional control was 42% in the accelerated group versus 30% in the conventional group (hazard ratio [HR] 0·63, 95% CI 0·49–0·83; p=0·004). Acute morbidity in the form of confluent mucositis was noted in 45 patients in the accelerated group and 22 patients in the conventional group (2·15, 1·27–3·35); severe skin reactions were noted in 87 patients in the accelerated group and 50 patients in the conventional group (1·91, 1·31–2·79). There were no significant differences in late radiation side-effects. Interpretation An accelerated schedule of radiotherapy for HNSCC was more effective than conventional fractionation, and since it does not require additional resources, might be a suitable new worldwide standard baseline treatment for radiotherapy of HNSCC. Funding International Atomic Energy Agency, Coordinated Research Project (IAEA-CRP E.3.30.18), the Danish Cancer Society, the Danish Strategic Research Council, and the Lundbeck Centre for Interventional Research in Radiation Oncology (CIRRO).

Purpose AK-2123, a nitrotriazole hypoxic cell sensitizer, has reportedly improved results in head and neck cancers, uterine cervical cancers and other solid tumours when added to radical radiotherapy. A prospectively randomised trial was initiated by the International Atomic Energy Agency (IAEA) evaluating AK-2123 and radiotherapy in treatment of uterine cervical cancer stage III and IV. Patients and methods A total of 462 patients were randomised from 8 centres. Patients from four centres were excluded due to lack of accrual, closing of the centre and insufficient documentation and reporting. The final study population consisted of 333 patients who were randomised between May 1995 and December 1998. Patients were randomised to either standard radical treatment (radiation therapy alone, RT) or standard radical radiotherapy and additional administration of AK-2123 (RT+AK-2123). The total dose of 45–50.8Gy was delivered by 20–28 fractions in an overall time of 4 – 5 1 2 weeks, with further dose escalation by brachytherapy or external beam. In the study arm, patients received 0.6g/sqm AK-2123 by intravenous administration before external beam radiotherapy, treating with AK-2123 on alternate days (e.g. Monday–Wednesday–Friday) during the entire course of external beam therapy. Following exclusion of 7 patients who did not undergo treatment, a total of 326 patients remained for evaluation. Results The rate of local tumour control was significantly higher in the group after radiotherapy and additional administration of AK-2123. Local tumour control was 61% (95/155) after AK-2123 and 46% (79/171) after radiotherapy alone ( p =0.006). The actuarial survival at 60 months was 57% after RT+AK-2123, compared to 41% after RT (Log Rank p =0.01). AK-2123 did neither increase gastro-intestinal toxicity nor was it attributed to any haematological toxicity. A mild peripheral toxicity (Grade 1: 13% and Grade 2: 2%) usually completely reversible was infrequently seen after AK-2123 administration. Conclusion We conclude that the addition of AK-2123 to radical radiotherapy significantly increases local tumour control and survival in advanced squamous cell cancer of the uterine cervix without the addition of any major toxicity.

Background and purpose : Single agent mitomycin c (MMC) has been shown to improve the outcome of radiotherapy in single institution trials. In order to confirm these findings in a broader worldwide setting, the International Atomic Energy Agency (IAEA) initiated a multicentre trial randomising between radiotherapy alone versus radiotherapy plus MMC. Material and methods : Patients with advanced head and neck cancer were treated with primary curative radiotherapy (66 Gy in 33 fractions with five fractions per week) ±a single injection (15 mg/m 2 ) of MMC at the end of the first week of radiotherapy. Stratification parameters were tumour localization, T-stage, N-stage, and institution. A total of 558 patients were recruited in the trial from February 1996 to December 1999. Insufficient accrual and reporting led to the exclusion of three centres. The final study population consisted of 478 patients from seven centres. Patients had stage III ( n =223) or stage IV ( n =255) squamous cell carcinoma of the oral cavity ( n =230), oropharynx ( n =140), hypopharynx ( n =65) or larynx ( n =43). Prognostic factors like age, gender, site, size, differentiation and stage were well balanced between the two arms. Results : The haematological side effects of MMC were very modest ( P =0.01). Conclusions : The study did not show any major influence of MMC on loco-regional tumour control, survival or morbidity after primary radiotherapy in stage III–IV head and neck cancer except in N0 patients where loco-regional control was significantly improved.

Purpose : To provide recommendations for the implementation of high dose rate (HDR) 192 Ir brachytherapy technology in developing countries. Methods : An Advisory Group Meeting of the International Atomic Energy Agency (IAEA) met to address the implementation of HDR 192 Ir brachytherapy technology in developing countries. These recommendations reflect only the personal opinions of the authors and do not necessarily represent the opinion of the IAEA. Results : An HDR treatment system should be purchased as a complete unit that includes the 192 Ir radioactive source, source loading unit, applicators, treatment planning system, and control console. Infrastructure support may require additional or improved buildings and procurement of or access to new imaging facilities. A supportive budget is needed for quarterly source replacement and the annual maintenance necessary to keep the system operational. The radiation oncologist, medical physicist, and technologist should be specially trained before HDR can be introduced. Training for the oncologist and medical physicist is an ongoing process as new techniques or sites of treatment are introduced. Procedures for quality assurance (QA) of patient treatment, and the planning system must be introduced. Emergency procedures with adequate training of all associated personnel must be in place. Conclusions : The decision to select HDR in preference to alternate methods of brachytherapy is influenced by the ability of the machine to treat a wide variety of clinical sites. In departments with personnel and budgetary resources to support this equipment appropriately, economic advantage becomes evident only if large numbers of patients are treated. Intangible benefits of source safety, personnel safety, and easy adaptation to fluctuating demand for treatments also require consideration when evaluating the need to introduce this treatment system.

A huge earthquake struck the northeast coast of the main island of Japan on 11 March 2011, triggering a tsunami with more than 10-m-high waves hitting the area. The earthquake was followed by numerous sustained aftershocks. The earthquake and aftershocks left almost 16,000 people dead and more than 2,800 missing (as of 11 March 2014). The earthquake affected the Fukushima Daiichi Nuclear Power Plant (NPP) of Tokyo Electric Power Company (TEPCO), causing serious damage to the NPP and resulting in large amounts of radioactive materials being released into not only controlled areas but also the environment. Damage was caused to the cooling systems of the NPP, although they automatically shut down after the earthquake. The trouble with the cooling systems led to hydrogen explosions and core meltdown. The major nuclides released on land were ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs. The release of these radioactive materials resulted in contamination of first responders and workers and also a high ambient dose of radiation around the NPP. The local hospital system, including that for radiation emergency medicine, was dysfunctional. Hospitals that had been designated as radiation emergency facilities were not able to function because the earthquake and tsunami had caused damage to their facilities; some of these were located within a 20-km radius of the NPP and in the evacuation areas. Local fire department personnel were also ordered to evacuate. Fukushima prefecture changed the screening level required for decontamination from 13,000 to 100,000 cpm, with decontamination by wiping being performed for over 13,000 cpm. However, as hospitals and fire departments had to abide by lower levels than that of the prefecture for receiving or transporting contaminated patients, these personnel could not accept or transport contaminated people from the NPPs. In addition, hospitals not designated as radiation emergency facilities would not receive patients from the NPPs because of concerns about the health effects of radiation. From this disaster, it was learned that basic knowledge of radiation and its effects is extremely important for health care providers.

A huge earthquake struck the northeast coast of the main island of Japan on March 11, 2011, triggering a tsunami with 14-15 meter-high waves hitting the area. The earthquake was followed by numerous sustained aftershocks. The earthquake affected the nuclear power plant (NPP) in Fukushima prefecture, resulting in large amounts of radioactive materials being released into the environment. The major nuclides released on land were ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs. Therefore, almost 170,000 people had to be evacuated or stay indoors. Besides the NPP and the telecommunications system, the earthquake also affected infrastructures such as the supplies of water and electricity as well as the radiation monitoring system. The local hospital system was dysfunctional; hospitals designated as radiation-emergency facilities were not able to function because of damage from the earthquake and tsunami, and some of them were located within a 20 km radius of the NPP, the designated evacuation zone. Local fire department personnel were also asked to evacuate. Furthermore, the affected hospitals had not established their evacuation plans at that time. We have learned from this "combined disaster" that the potential for damage to lifelines as well as the monitoring systems for radiation in case of an earthquake requires our intense focus and vigilance, and that hospitals need comprehensive plans for evacuation, including patients requiring life support equipment during and after a nuclear disaster. There is an urgent need for a "combined disaster" strategy, and this should be emphasized in current disaster planning and response.

Although tumor clearance is a common criterion in assessing the impact of radiotherapy (RT), it is not always reliable. Patterns of tumor clearance were determined using 91 metastatic lymph nodes (LNs) from 51 patients with head and neck tumors treated by definitive RT (61-80 Gy) or preoperative RT (43-65 Gy). Clearance rate (CR) was estimated as a daily volume decrement expressed as a ratio to the pre-RT LN volume. CR was greater for the so-called radioresponsive nasopharyngeal subgroups and more poorly differentiated than those of oral cavity and well-differentiated, respectively. Histologically, LNs that were removed following RT consisted mainly of fibrous tissues, necrotic tissues, and few cancer cells. There was no difference in CR between the cancer-cell-positive group (n = 21) and the cancer-cell-negative group (n = 31). Although the CR may reflect inherent radiosensitivity of tumor cells, tumor persistence predicts the amount of oncologically inactive materials rather than that of remaining cancer cells.