著者
堀 雅明 中井 斌
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.11, no.1, pp.1-11, 1976 (Released:2010-02-25)
参考文献数
37
被引用文献数
1 1

Genetic risk assessment for potential hazard from environmental tritium to man becomes important with increasing nuclear-power industry. The purpose of this short review is to discuss the possible genetic effects of tritium from a view of genetic risk estimation.The discussion is based mainly on our experimental results on the chromosome aberrations induced in human lymphocytes by tritium at the very low-level. The types of chromosome aberrations induced by radiation from tritium incorporated into the cells are mostly chromatid types. The most interesting finding is that the dose-response relationship observed in both tritiated-water and tritiated-thymidine is composed of two phases. The examination on the nature of two-phase dose-response relationship is very important not only for the mechanisms of chromosome aberrations, but also for the evaluation of genetic risk from low-level radiation.
著者
甲斐 倫明
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.18, no.1, pp.3-10, 1983 (Released:2010-02-25)
参考文献数
36
被引用文献数
1 4 3

The purpose of the present study was to estimate a biological half-life of iodine in normal Japanese thyroid for the calculation of the thyroid dose from iodine-129 with a long physical half-life. The Japanese takes stable iodine through sea food in a more considerable amount than the Caucasian who is assumed to be the Reference Man recommended by ICRP. It can be shown by medical research in thyroidology that the iodine metabolism between the Japanese and the Caucasian is different owing to the amount of the ingested stable iodine. Furthermore, in the Japanese the thyroid releases inorganic iodine since it takes up iodine more than physiologically required to produce thyroid hormone.We calculated the biological half-life of iodine for both the Japanese and the Caucasian by using a five compartment model. The following results were delivered. The biological half-life in the Japanese was approximately 40 days, which was in agreement with the values reported before. On the other hand, that of the Caucasian was 130 days nearly equal to the Reference Man.
著者
河合 広 本田 嘉秀 森嶋 弥重 古賀 妙子 木村 雄一郎 西脇 安
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.3, no.2, pp.273-279, 1968 (Released:2010-03-15)
参考文献数
13

We have observed properties of radioactive fallout originated from the first, the second, the third, the fourth and the fifth Chinese nuclear explosions. The differences in gross beta-activities, activities per unit volume and their particle sizes of highly radioactive particles are discussed with relation to the differences in burst conditions among the five explosions from which they originated.It was found that radioactivities of the highly radioactive particles were roughly proportional to their volumes. The differences in the radioactive decay rates of highly radioactive fallout particles were found in connection with their colors.From the results of decay characteristics of gross beta-activities and γ-ray spectra of fallout samples, it was found that the contribution of radioactivities of 239Np in samples from the fifth Chinese explosion was larger than that from the third Chinese explosion.In comparison between the γ-ray spectra of highly radioactive fallout particles from the third and the fifth Chinese explosions, the particles from the third Chinese explosion were enriched in 95Zr+95Nb and impoverished in 103Ru, while on the particles from the fifth Chinese explosion, the reverse of phenomenon above mentioned was observed.
著者
石川 徹夫 安岡 由美 長濱 裕幸 川田 祐介 大森 康孝 床次 眞司 志野木 正樹
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.43, no.3, pp.253-267, 2008 (Released:2010-08-05)
参考文献数
70
被引用文献数
2 3

Before the 1995 Hyogoken-Nanbu earthquake, various geochemical precursors were observed in the aftershock area: chloride ion concentration, groundwater discharge rate, groundwater radon concentration and so on. Kobe Pharmaceutical University (KPU) is located about 25km northeast from the epicenter and within the aftershock area. Atmospheric radon concentration had been continuously measured from 1984 at KPU, using a flow-type ionization chamber. The radon concentration data were analyzed using the smoothed residual values which represent the daily minimum of radon concentration with the exclusion of normalized seasonal variation. The radon concentration (smoothed residual values) demonstrated an upward trend about two months before the Hyogoken-Nanbu earthquake. The trend can be well fitted to a log-periodic model related to earthquake fault dynamics. As a result of model fitting, a critical point was calculated to be between 13 and 27 January 1995, which was in good agreement with the occurrence date of earthquake (17 January 1995). The mechanism of radon anomaly before earthquakes is not fully understood. However, it might be possible to detect atmospheric radon anomaly as a precursor before a large earthquake, if (1) the measurement is conducted near the earthquake fault, (2) the monitoring station is located on granite (radon-rich) areas, and (3) the measurement is conducted for more than several years before the earthquake to obtain background data.
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
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
土屋 武彦 法村 俊之 山本 久夫 畠山 智
出版者
Japan Health Physics Society
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
岩倉 哲男
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.10, no.3, pp.131-140, 1975 (Released:2010-02-25)
参考文献数
28

An attempt is made to review behavior of tritium released into the environment in order to give preliminary knowledges for monitoring present and future levels of tritium in the environment. A systematic distribution of bomb-produced tritium on a global scale has been recognized from an evaluation of the precipitation data conducted by the IAEA-WMO Precipitation Network Survey. Latitudinal dependence and continental effect of the tritium concentration in precipitation were found pronouncedly. The mean residence times of several compartments of hydrological cycle for tritiumm are discussed topically. Recent tritium concentration in environmental water in Japan are summarized. Organically bound tritium in sediments, aquatic plants, fish, and foodstaffs sometimes showed higher concentration than tritium in ambient water. This is probably explained as memory effect or inheritance effect through eco-systems due to long residence time of organically bound tritium. Instrumentation, detection limit and dose calculation for tritium monitoring are proposed. Tritium surveillance activities conducted by U. S. Government are reviewed also historically with some representative data.
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 26

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
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
宮本 霧子
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.43, no.1, pp.50-59, 2008 (Released:2010-08-05)
参考文献数
9

The international program, known as the EMRAS (Environmental Modeling for Radiation Safety) project was carried out in 2003-2007. “The working group for modelling of tritium and carbon-14 transfer to biota and man” took an active part in the EMRAS by presenting the eight scenarios for the purpose of the validation of the environmental tritium model. Three scenarios were concerned about uptake and depuration of tritium by bivalves and various biological species in a steady state lake. Two scenarios dealt with tritium uptake of soybean and pine tree, other two did pig metabolism and various products from a farm land. One scenario was designed to estimate human dose exposed by a hypothetical shot of tritium release in the atmosphere. OBT definition and revision of parameter values in the Handbook, IAEA-TRS No. 364 were also carried out.
著者
村上 博幸 箕輪 雄資 新野 二男 松井 智明 大畑 勉
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.16, no.3, pp.255-258, 1981 (Released:2010-02-25)
参考文献数
2
被引用文献数
1 1
著者
丸山 隆司
出版者
Japan Health Physics Society
雑誌
保健物理 (ISSN:03676110)
巻号頁・発行日
vol.21, no.4, pp.273-283, 1986 (Released:2010-02-25)
参考文献数
18