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Hokama, Tomonori; Kimura, Masanori; Togawa, Orihiko
JAEA-Research 2023-010, 57 Pages, 2024/02
In the case of a nuclear accident, itis planned to perform simple measurement of radioactive iodine radioactivity in the thyroid of residents. The screening level for simple measurement is set at 0.20 Sv/h as a reference, and it is required to be reviewed appropriately according to the situation such as a nuclear accident. However, a specific method for reviewing the screening level is not shown. When reviewing the screening level, it is important to take into account factors related to the feasibility of simple measurement, such as the judgment level for internal exposure dose of the thyroid and the duration of the measurement period. In this study, we organized the derivation process of 0.20 Sv/h, which was set as the reference for screening level, and considered the feasibility of the reviewing of screening level. We calculated the relationship between the judgment level and the duration of simple measurement for each screening level, ranging from 0.025 to 0.50 Sv/h. Then, the feasibility of the reviewing of screening level was considered. It was found that reviewing the screening level is technically feasible, provided that the judgment level and the duration of simple measurement are appropriate. However, assuming that simple measurement will be performed in an actual nuclear accident, we assessed that it would be reasonable to review the screening level within the range of 0.030 to 0.20 Sv/h, in a situation where the duration of simple measurement must be extended.
Suzuki, Gen*; Ishikawa, Tetsuo*; Oba, Takashi*; Hasegawa, Arifumi*; Nagai, Haruyasu; Miyatake, Hirokazu*; Yoshizawa, Nobuaki*
Journal of Radiation Research (Internet), 63(6), p.796 - 804, 2022/11
Times Cited Count:2 Percentile:44.25(Biology)To elucidate the association between radiation dose and thyroid cancer after the 2011 Fukushima Daiichi Nuclear Power Station (FDNPS) accident, it is essential to estimate individual thyroid equivalent doses (TEDs) to children. In a previous study, we reported a methodology for reconstructing TEDs from inhalation based on individual behavioural survey sheets combined with a spatiotemporal radionuclides database constructed by an atmospheric transport, diffusion, and deposition model (ATDM). In the present study, we further refined our methodology and estimated the combined TEDs from inhalation and ingestion among children in 16 municipalities around the nuclear power station utilizing 3,256 individual whereabouts questionnaire survey sheets. Distributions of estimated TEDs were similar to estimates based on direct thyroid measurements in 1080 children in Iwaki City, Kawamata Town, Iitate Village, and Minamisoma City. Mean TEDs in 1-year-old children ranged from 1.3 mSv in Date City to 14.9 mSv in Odaka Ward in Minamisoma City, and the 95th percentiles varied from 2.3 mSv in Date City to 28.8 mSv in Namie Town. In the future, this methodology can be useful for a case-control study of thyroid cancer after the FDNPS accident.
Tanimura, Yoshihiko
FBNews, (548), p.1 - 5, 2022/08
In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. The portable thyroid dose monitoring system with the radiation shield which can be used in a high dose rate condition has been developed. In this paper, the outline of the monitoring system and the performance test results using the system will be described.
Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Nishino, Sho; Takahashi, Masa
Radiation Measurements, 137, p.106389_1 - 106389_5, 2020/09
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)A portable thyroid dose monitoring system has been developed at the Japan Atomic Energy Agency (JAEA) to assess the thyroid equivalent dose for workers and members of the public in a high dose rate environment. The background (B.G.) photon correction is required for an accurate measurement in a high dose rate environment at an early stage after a nuclear accident. We developed the B.G. photon correction method using cylindrical PMMA phantoms.
Nishino, Sho; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Takahashi, Masa
Radiation Measurements, 134, p.106292_1 - 106292_5, 2020/06
Times Cited Count:4 Percentile:44.4(Nuclear Science & Technology)In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. The portable thyroid dose monitoring system which can be used in a high dose rate condition is in development. In this presentation, the result of performance test using prototype model will be described.
Yoshitomi, Hiroshi; Nishino, Sho; Tanimura, Yoshihiko; Takahashi, Masa
Radiation Measurements, 133, p.106279_1 - 106279_6, 2020/04
Times Cited Count:5 Percentile:52.81(Nuclear Science & Technology)Uncertainty of the body size on the counting efficiency of a newly developed thyroid monitor was estimated by Monte Carlo simulations using several voxel phantoms. Overlying tissue thickness was a major impact factor on the counting efficiency. As a result, uncertainty related to the body size of the monitored subject was found to be 25%.
Yonezawa, Chushiro; Matsue, Hideaki; Yukawa, M.*
Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.105 - 109, 2003/01
Times Cited Count:5 Percentile:36.77(Chemistry, Analytical)no abstracts in English
Onodera, Junichi
Enerugi Rebyu, 21(7), p.23 - 26, 2001/07
no abstracts in English
Matsunaga, Takeshi; Kobayashi, Kensuke
Hoken Butsuri, 36(1), p.31 - 44, 2001/03
no abstracts in English
Matsunaga, Takeshi; Kobayashi, Kensuke
Proceedings of 10th International Congress of the International Radiation Protection Association (IRPA-10) (CD-ROM), 10 Pages, 2000/05
no abstracts in English
Tsujimura, Norio; Shinohara, Kunihiko; Momose, Takumaro
PNC TN8410 97-207, 25 Pages, 1997/06
None
; Mizushita, Seiichi
IRPA9: 1996 International Congress on Radiation Protection, Proceedings, 2, p.498 - 500, 1996/00
no abstracts in English
Togawa, Orihiko
Hoken Butsuri, 27, p.27 - 32, 1992/00
no abstracts in English
*; Mizushita, Seiichi; ; *; Yoshida, Makoto; ; Minami, Kentaro
Radioisotopes, 39(4), p.178 - 187, 1990/04
no abstracts in English
; ; Yabe, Akira
Hoken Butsuri, 7(4), p.213 - 219, 1972/04
no abstracts in English
Tanimura, Yoshihiko; Nishino, Sho; Yoshitomi, Hiroshi; Takahashi, Masa
no journal, ,
A portable thyroid dose monitoring system using -ray spectrometers has been developed in order to assess the equivalent dose to the thyroid for workers and members of the public in a high dose rate environment at an early stage after a nuclear accident. The Conceptual design of the system will be described.
Yoshitomi, Hiroshi; Nishino, Sho; Takahashi, Masa; Tanimura, Yoshihiko
no journal, ,
The detector positions of the thyroid monitor were determined by Monte Carlo calculations using voxel phantoms so that the counting efficiency of the thyroid monitor was adequately high and less dependent on the age. The calibration conditions to reproduce the thyroid measurements of the monitored subjects were found using simplified physical phantoms including point sources.
Nishino, Sho; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Takahashi, Masa
no journal, ,
A portable thyroid dose monitoring system using -ray spectrometers has been developed in JAEA. In this presentation, the results of performance tests of candidate detectors (CdZnTe detector and LaBr/SrI scintillation detectors) and optimization of radiation shield's design will be described.
Yoshitomi, Hiroshi; Nishino, Sho; Takahashi, Masa; Tanimura, Yoshihiko
no journal, ,
Nishino, Sho; Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Takahashi, Masa
no journal, ,
In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. We propose conceptual design of the portable thyroid dose monitoring system consisting of two -ray spectrometers and radiation shield, which is easily used at evacuation centers and incident command posts in the radiologically affected area. The experimental study of detectors and radiation shield were performed to confirm if the proposed monitor can satisfy the performance requirements. As a result, it was confirmed that the proposed monitor can assess thyroid equivalent dose less than 10 mSv by adopting CdZnTe or LaBr detectors with a tungsten heavy alloy shield, even in a high dose rate condition around several 10 Svh.