著者
中野 政尚 國分 祐司 武石 稔
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.44, no.1, pp.60-65, 2009 (Released:2010-10-08)
参考文献数
15

The tritium concentrations in seawater collected around the Tokai Reprpcessing Plant (TRP) were measured for 10,800 samples in 30 years from 1978. The tritium concentration, dillution factor and diffusion situation were investigated. As a result, the tritium was occationaly detected due to the discharge from TRP. But it was considered to be the result of expected diffusion assumed in the safety assessment. It was confirmed that the tritium concentration was much lower than the concentration limit defined in the law and that it was not concern of environmental safety.
著者
渡邉 正己
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.47, no.2, pp.118-123, 2012 (Released:2012-12-07)
参考文献数
15

It has been believed that the first target of radiation carcinogenesis is DNA. However, this is not proved for radiation carcinogenesis yet. We discovered that frequency of aneuploid cell was closely related to that of radiation-induced cell transformation and natural cell transformation by high-density cultivation, but gene mutation was not. Cell with p53 gene becomes tetraploid, but does not get tumorigenicity. On the other hand, cells without p53 gene function become a triploid easily, and acquire tumorigenicity. Both radiation exposure and high-density cultivation elevated the level of intracellular oxidative radicals. These radicals induced centrosome destabilization and produced cells carrying extra centrosome, which promote merotelic attachment of chromosome by altering spindle geometry. Unresolved merotelic attachments can give rise to lagging chromosomes at anaphase. Aneuploidy was seen in high frequency in early process of cell transformation. These results strongly suggest that a main target of carcinogenesis by low dose radiation is not DNA, but is centrosome, which are the proteins to constitute chromosomal homeostasis maintenance mechanism. In addition, this route may be the same as that of natural carcinogenesis. These serial results support necessity of a review of a LNT hypothesis at a radioprotective point of view.
著者
脇田 宏
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.31, no.2, pp.215-222, 1996 (Released:2010-02-25)
参考文献数
15
被引用文献数
3 4
著者
草間 朋子 中川 健朗 吉澤 康雄
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.20, no.4, pp.399-406, 1985 (Released:2010-02-25)
参考文献数
24
被引用文献数
1

The concept of population dose is of importance and of interest at the point of radiation protection of puplic. We devided it into two categories, source-related population dose and individual-related population dose, and estimated each population dose of Japan. We surveyed all sources that caused exposure to Japanese population. A number of sources, both naturally-occuring and man-made, contributed to population exposure. According to source-related dose assessment, average annual effective dose equivalent was about 3.3mSv, and about half of which, i. e. 1.6mSv, was given from medical exposure. And from the results of individual-related dose assessment we proposed the allocation of the annual dose limit of public for each controllable source, that is, 2.5mSv/yr to nuclear faculties, 1.0mSv/yr to miscellaneous sources, 1.5mSv/yr to probablistic exposure.
著者
Noriko KOBAYASHI
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.54, no.1, pp.55-65, 2019-04-18 (Released:2019-09-03)
参考文献数
20

The International Commission on Radiological Protection (ICRP) internal dose assessment model, currently adopted in Japanese regulation, assumes uniform distribution of radionuclides in bone marrow blood (ICRP Publication 60). Recent studies have revealed a localization of hematopoietic stem cells (HSCs) and immune cells in the perivascular region of the bone marrow sinusoids, suggesting a need to consider nonuniform distributions of the blood source and HSCs. To evaluate energy transfer to HSCs, a simplified model of cervical vertebrae with bone tissues and blood vessels was built using data from the adult Japanese male phantom. Doses absorbed by HSCs from blood and hard bone sources were calculated using a Monte Carlo simulation, and absorbed fractions (AFs) and specific absorbed fractions (SAFs) from electrons were compared with those in the ICRP 1990 model. In the cervical vascular model, electron SAFs from sinusoidal blood in the red bone marrow (RBM) to the target perivascular region were 1.2 to 6.9 times higher than the SAF in the ICRP 1990 model, suggesting an underestimation of the RBM dose. Electrons from the cortical bone source to the perisinusoidal target exhibited energy transfer. The ICRP 1990 model underestimates electron SAFs from radionuclides in sinusoidal blood and cortical bones. A more elaborate model is needed to examine doses for the RBM and effects on hematopoietic and immune functions.
著者
藤原 慶子 山崎 敬三 高橋 知之 高橋 千太郎 北川 晃三 神藤 克人
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.47, no.4, pp.282-285, 2012 (Released:2013-12-17)
参考文献数
8

After the Fukushima Daiichi Nuclear Power Plant Accident, many people are concerned about the contamination of radioactive substances in their ordinary surrounding environment. In this study, we determined the levels of radioactive contamination with 137Cs in towels, very common textile products in our life, after exposing those to the soil collected from a farm field near Fukushima city. Three kinds of towels made from the same cotton fiber with different thickness were exposed to the soil under dry or water-suspension conditions. The radioactivities of 137Cs retained/absorbed were 30-50% of the loaded radioactivity per gram weight of the towel. When their weight and absorbency are taken into consideration, the differences in thickness did not so much affect the above values. Under standard washing condition, which mimic those with household washing machine, almost all the radioactive cesium were removed from the towels contaminated under the dry conditions, whereas only 50-70% were removed when the towels were contaminated under the wet conditions. A commercial soil-release treatment (Preshade-SR) didn't reduce the contamination under both dry and wet conditions, although processing the towels with silver nano-particles did.
著者
渡部 輝久
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.41, no.4, pp.221-233, 2006 (Released:2010-08-05)
参考文献数
25

Environmental protection is one of the key issues in the prospective policy and strategy of radiation protection. In this context, numerous efforts have been made for developing the framework for the protection of non-human species from ionizing radiation, especially in European countries and Unite States. The present report summarizes knowledge so far attained on the assessment of doses and radiation impact on marine organisms. Special attention was directed to the methodology for calculating absorbed doses of marine organisms, based on which a case study was also carried out for estimating absorbed dose rate of several species of marine organisms inhabiting in the coastal sea off Rokkasho-Mura, Aomori Prefecture where a spent nuclear fuel reprocessing plant came into operation.
著者
森内 茂 堤 正博 斎藤 公明
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.25, no.2, pp.121-128, 1990 (Released:2010-02-25)
参考文献数
13
被引用文献数
21 22

A practical conversion factor to estimate the value of effective dose equivalent rate in Sv unit from absorbed dose rate in air in Gy unit was examined for natural gamma radiations. The experimental examination was carried out by two methods; one measures the effective dose equivalent rate directly by using a measuring instrument having effective dose equivalent response for isotropic gamma radiations and the other obtaines it from calculation applying the gamma flux-to-effective dose equivalent factor to actual gamma energy spectrum measured in various indoor and outdoor places.From these investigations the value of the quotient of effective dose equivalent to absorbed dose in air was found do be 0.748±0.007 Sv per Gy for natural radiation exposures in various environments. The value of the quotient 0.7, which is adopted to applied to environmental gamma radiations in the UNSCEAR 1982 and 1988 Reports, was clarified to be about 7% lower than the one obtained experimentally for natural gamma radiations.
著者
竹安 正則 住谷 秀一 古田 定昭
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.48, no.3, pp.141-149, 2013 (Released:2013-12-10)
参考文献数
13

On the basis of the measurement results of airborne radionuclide concentrations in the Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, the committed effective dose to adults and the committed equivalent dose to thyroid of infants by inhalation were estimated for various indoor and outdoor exposure scenarios. It was demonstrated that the indoor to outdoor airborne radionuclide concentration ratio had a dominant effect on the dose estimate. The committed effective dose to adults was estimated to 0.098 mSv, and the committed equivalent dose to thyroid of infants was 1.8 mSv. These doses were about 1/6 and about 1/9, respectively, compared to the provisional ones with such assumptions as continuous outdoor stay.
著者
石原 弘
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.46, no.3, pp.179-183, 2011 (Released:2012-07-28)
参考文献数
1
著者
谷村 嘉彦 富田 純平 吉富 寛 吉澤 道夫 箱崎 亮三 高橋 荘平
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.51, no.3, pp.141-146, 2016 (Released:2016-11-18)
参考文献数
10

Photon spectra were measured inside and outside a house in Minami-Soma city by using a NaI(Tl) scintillation spectrometer. The photons were categorized into three groups according to their energy. The groups were (1) scattered photons, which include low energy photons, (2) direct photons from 134Cs and 137Cs sources and (3) the other photons. Then the ratios of the ambient dose equivalents H*(10) of the scattered photons to those of the direct photons from the 134Cs and 137Cs sources have been evaluated from the measured photon spectra. The ratios are high inside the house compared with those out of the house. It was found that the scattered photons contribute to the H*(10) by more than 50% inside the house. The ambient dose equivalent average energies of the scattered photons are around 0.25 MeV both inside and outside the house. These data is worthwhile to design the optimum shielding for the protection against the public radiation exposure.
著者
日本保健物理学会医療放射線リスク専門研究会
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.46, no.1, pp.42-51, 2011 (Released:2012-01-25)
参考文献数
20
被引用文献数
1

Radiation use in medicine generally gives us the benefit that outweighs the risk. However, some patients are much concerned about the risk while some medical people are unaware of radiation risk. The aim of this report is to review the low dose risk not only in the reports of ICRP, UNSCEAR, BEIR and French academy but also in the scientific papers that have been paid attention to. On these bases, we discuss the low dose risk and how we face the risk in medicine in order to go for medical use of radiation to the right way. In particular, we hope this report will support medical people as well as radiation protection experts should understand the radiation risk in medicine on current scientific basis.
著者
土屋 武彦 法村 俊之 山本 久夫 畠山 智
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.20, no.3, pp.279-284, 1985 (Released:2010-02-25)
参考文献数
10
被引用文献数
2 1

The radiations emitted from the front surface of CRT of a color-television and a personal-computer display were measured by GM-counter. No difference was observed in the radiation dose between the cases with and without application of a high voltage to the CRT. The radiations were also measured by Si- and Ge-semiconductor spectrometers. It was found that the radiations emitted from CRT were composed of β- and γ-rays, and were essentially emitted from 40K and the nuclides of uranium- and thorium- series contained within the front glass of CRT. The exposure dose rate of these radiations at 50cm from the surface of CRT was, however, less than 1.6×10-3mrem/hr, and it was practically negligible in comparison with that of natural background radiations.
著者
JAEA大洗プルトニウム 汚染事故ワーキンググループ 岩井 敏 佐々木 道也 桧垣 正吾 山西 弘城 甲斐 倫明
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.53, no.4, pp.271-281, 2018 (Released:2019-03-03)
参考文献数
15

On June 6, 2017, in the hood of the analyzing room at Plutonium Fuel Facility of Oarai Research and Development Center in Japan Atomic Energy Agency, five workers were checking the storage container of fast reactor nuclear fuel material. Around 11:15 a.m., vinyl bags in the container of the fuel material including plutonium and enriched uranium burst during the inspection work. All the workers heard the bang; which caused misty dust leakage from the container. This event caused significant skin α-contamination for four workers and nasal cavity α-contamination for three workers. Decontamination was conducted for workers in the shower room. Then, the five workers were transferred to the Nuclear Fuel Cycle Engineering Laboratory to evaluate inhalation intake of plutonium etc. in lungs. The maximum values of 2.2 × 104 Bq for 239Pu and 2.2 × 102 Bq for 241Am were estimated by the lung monitor. From these results, injection of chelate agent was conducted for prompt excretion of plutonium etc. Next morning, the five workers were transferred to the National Institute of Radiological Sciences for treatments including decontamination of their skin and measurement by lung monitor. Then no obvious energy peak was confirmed for plutonium. The Japan Health Physics Society launched the ad-hoc working group for plutonium intake accident around the middle of June to survey issues and to extract lessons on radiological protection. We will report the activity of the working group.
著者
浜田 信行
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.53, no.2, pp.116-118, 2018 (Released:2018-09-13)
参考文献数
14
被引用文献数
1
著者
外川 織彦
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.27, no.1, pp.27-32, 1992 (Released:2010-02-25)
参考文献数
17
被引用文献数
1

Internal dose coefficients for ingestion and inhalation of radioiodine were preliminarily calculated considering the metabolic characteristics of Japanese. In the calculation, the fractional uptake by thyroid (f) of iodine entering blood and biological half-life in thyroid (Tb) were reflected among the data peculiar to Japanese concerning thyroid structure and iodine metabolism in thyroid. A metabolic model for iodine used here was based on the three-compartment recycle model described in the ICRP Publication 30. As to the parameters of f and Tb, the values of 0.2 and 40 days reported for Japanese were used instead of those of 0.3 and 80 days adopted by ICRP.The dose coefficients for Japanese calculated here are smaller than those for Reference Man of Caucasian. The author expects that the coefficients will be used for radiation protection purpose for workers and adults of the public in Japan.
著者
内山 正史
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.31, no.2, pp.143-150, 1996 (Released:2010-02-25)
参考文献数
10
著者
斎藤 公明
出版者
日本保健物理学会
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.46, no.3, pp.210-214, 2011 (Released:2012-07-28)
被引用文献数
4 4