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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.
Furuta, Takuya; Koba, Yusuke*; Hashimoto, Shintaro; Chang, W.*; Yonai, Shunsuke*; Matsumoto, Shinnosuke*; Ishikawa, Akihisa*; Sato, Tatsuhiko
Physics in Medicine & Biology, 67(14), p.145002_1 - 145002_15, 2022/07
Times Cited Count：3 Percentile：44.25(Engineering, Biomedical)Carbon ion radiotherapy has an advantage over conventional radiotherapy such that its superior dose concentration on the tumor helps to reduce unwanted dose to surrounding normal tissues. Nevertheless, a little dose to normal tissues, which is a potential risk of secondary cancer, is still unavoidable. The Monte Carlo simulation is a good candidate for the tool to assess secondary cancer risk, including the contributions of secondary particles produced by nuclear reactions. We therefore developed a new dose reconstruction system implementing PHITS as the engine. In this system, the PHITS input is automatically created from the DICOM data sets recorded in the treatment planning. The developed system was validated by comparing to experimental dose distribution in water and treatment plan on an anthropomorphic phantom. This system will be used for retrospective studies using the patient data in National Institute for Quantum and Science and Technology.
Chang, W.*; Koba, Yusuke*; Furuta, Takuya; Yonai, Shunsuke*; Hashimoto, Shintaro; Matsumoto, Shinnosuke*; Sato, Tatsuhiko
Journal of Radiation Research (Internet), 62(5), p.846 - 855, 2021/09
Times Cited Count：3 Percentile：25.1(Biology)With the aim of developing a revaluation tool of treatment plan in carbon-ion radiotherapy using Monte Carlo (MC) simulation, we propose two methods; one is dedicated to identify realistic-tissue materials from a CT image with satisfying the well-calibrated relationship between CT numbers and stopping power ratio (SPR) provided by TPS, and the other is to estimate dose to water considering the particle- and energy-dependent SPR between realistic tissue materials and water. We validated these proposed methods by computing depth dose distribution in homogeneous and heterogeneous phantoms composed of human tissue materials and water irradiated by a 400 MeV/u carbon beam with 8 cm SOBP using a MC simulation code PHITS and comparing with results of conventional treatment planning system (TPS). Our result suggested that use of water as a surrogate of real tissue materials, which is adopted in conventional TPS, is inadequate for dose estimation from secondary particles because their production rates cannot be scaled by SPR of the primary particle in water. We therefore concluded that the proposed methods can play important roles in the reevaluation of the treatment plans in carbon-ion radiotherapy.
Yoshitomi, Hiroshi; Hagiwara, Masayuki*; Kowatari, Munehiko; Nishino, Sho; Sanami, Toshiya*; Iwase, Hiroshi*
Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1188 - 1195, 2017/11
The equivalent doses to the lens of the eye and extremities for radiation workers should be assessed properly to ensure that the dose limits are not exceeded. Recently, the following two issues has pressed demand on more appropriate evaluation of the equivalent doses of the lens of the eye and extremity. One is the new occupational dose limit for the lens of the eye the ICRP recommended. The other is growing demand on handling of highly activated materials in the maintenance works of an accelerator and contaminated materials during the decommissioning works of nuclear facility, which increases the potential exposure risk to the extremities to a wider variety of radio-nuclides. Since the points to be assessed for the exposures to the lens of the eye and the extremities are apart from the trunk, the homogeneity of the radiation fields would be significantly impact on the assessment of these equivalent doses. However, there has been no sufficient and available method to identify the nonhomogeneous situations systematically in terms of the eye lens or extremity monitoring. The goal of this study is to provide the framework to identify the nonhomogeneous exposure situations. In order to fulfil this purpose, newly proposed indices to represent the homogeneity were calculated by Monte Carlo simulation incorporated with mathematical phantom, verifying the benchmark measurements. Important parameters that significantly impact on these indices were also shown from the various trials of calculations of homogeneity indices.
Yokoyama, Sumi*; Hamada, Nobuyuki*; Hayashida, Toshiyuki*; Tsujimura, Norio; Tatsuzaki, Hideo*; Kurosawa, Tadahiro*; Nabatame, Kuniaki*; Oguchi, Hiroyuki*; Ono, Kazuko*; Kawaura, Chiyo*; et al.
Journal of Radiological Protection, 37(3), p.659 - 683, 2017/09
Times Cited Count：15 Percentile：81.76(Environmental Sciences)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 situations 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 situations in 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 situations in Japan, but we believe such information sharing will be useful in many other countries.
Imaizumi, Mitsuru*; Sumita, Taishi*; Kawakita, Shiro*; Oshima, Takeshi; Ito, Hisayoshi; Kuwajima, Saburo*
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.563 - 566, 2005/00
no abstracts in English
Nomura, Yasushi*; Okuno, Hiroshi; Miyoshi, Yoshinori
JAERI-Tech 2004-030, 64 Pages, 2004/03
JAERI-Tech-2004-030.pdf:4.59MB
no abstracts in English
Matsui, Shingo*; Muto, Yasushi*; Shiina, Yasuaki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(2), p.175 - 186, 2003/06
no abstracts in English
Kinase, Sakae; Kimura, Masaya*; Noguchi, Hiroshi
Radioisotopes, 52(6), p.277 - 284, 2003/06
We have studied the formulation of skeletal substitutes for a in vivo calibration phantom using the basic data method. An equation for calculating the optimum relative mass of the corrective additives was developed. Also, epoxy resin based tissue substitutes simulating the skeleton were developed. The substitutes were examined for the photon transmissions using 16.6keV KX-rays from 93mNb and 59.5keV gamma rays from 241Am. It was found that the experimental transmission curves of the substitutes are in good agreement with the calculated ones. The equation for the corrective additive was validated. The skeletal substitutes were found to be suitable as the corresponding tissues defined in ICRP Publication.23.
Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Iwasaki, Midori*; Miyazawa, Chuzo*; Hamada, Tatsuji*; Funabiki, Jun*
Journal of Nuclear Science and Technology, 39(Suppl.2), p.1314 - 1317, 2002/08
An analysis of dose to tooth enamel was carried out to develop a method that can predict the organdose and effective dose by the Electron Spin Resonance (ESR) dosimetry using teeth for external photon exposure. Absorbed dose to tooth enamel were obtained with Monte Carlo calculations using EGS4 code with a mathematical human model, which has a newly defined teeth-part. Experiments were also carried out to investigate the dose at the tooth area with a physical head phantom. The calculated doses to tooth enamel were, however, less than the measured doses with the TLDs for the case of photon incidence from the back of a human body. Then, a computational human model, called a “Voxel (Volume-pixel) type" phantom was constructed based upon a computed topography (CT) image of the physical head phantom used in the experiments.The additional Monte Carlo calculations were performed to verify the results in the experiments with the EGS4 in conjunction with user's code UCPIXEL and the Voxel type phantom.
Fujita, Takaaki; Kamada, Yutaka; Ide, Shunsuke; Takeji, Satoru; Sakamoto, Yoshiteru; Isayama, Akihiko; Suzuki, Takahiro; Oikawa, Toshihiro; Fukuda, Takeshi; JT-60 Team
Nuclear Fusion, 42(2), p.180 - 186, 2002/02
Times Cited Count：31 Percentile：68.18(Physics, Fluids & Plasmas)no abstracts in English
Nomura, Yasushi; Murazaki, Minoru*; Okuno, Hiroshi
JAERI-Data/Code 2001-029, 120 Pages, 2001/11
JAERI-Data-Code-2001-029.pdf:6.16MB
no abstracts in English
-ray absorbed doses under criticality accident conditions at TRACY using tissue-equivalent dosimetersSono, Hiroki; Yanagisawa, Hiroshi; Ono, Akio; Kojima, Takuji; Soramasu, Noboru*
Nuclear Science and Engineering, 139(2), p.209 - 220, 2001/10
Times Cited Count：7 Percentile：48.66(Nuclear Science & Technology)no abstracts in English
-ray doses on criticality accidents of low-enriched uranyl nitrate solution using tissue-equivalent dosimeters at the TRACY facilitySono, Hiroki; Yanagisawa, Hiroshi; Ono, Akio; Kojima, Takuji; Miyoshi, Yoshinori; Soramasu, Noboru*
Proceedings of the ANS International Topical Meeting on Advances in Reactor Physics and Mathematics and Computation into the Next Millennium (PHYSOR2000) (CD-ROM), 9 Pages, 2000/05
no abstracts in English
Shimo, Michito*; *
JNC TJ7400 2000-008, 157 Pages, 2000/03
JNC-TJ7400-2000-008.pdf:4.02MB
no abstracts in English
Fujita, Takaaki; Kamada, Yutaka; Ishida, Shinichi; Neyatani, Yuzuru; Oikawa, Toshihiro; Ide, Shunsuke; Takeji, Satoru; Koide, Yoshihiko; Isayama, Akihiko; Fukuda, Takeshi; et al.
Nuclear Fusion, 39(11Y), p.1627 - 1636, 1999/11
Times Cited Count：93 Percentile：91.89(Physics, Fluids & Plasmas)no abstracts in English
Ishida, Shinichi; JT-60 Team
Nuclear Fusion, 39(9Y), p.1211 - 1226, 1999/09
Times Cited Count：40 Percentile：75.08(Physics, Fluids & Plasmas)no abstracts in English
*; Futakawa, Masatoshi; Ioka, Ikuo; Onuki, Kaoru; Shimizu, Saburo; Eto, Motokuni; Oku, Tatsuo*; *
Zairyo, 48(7), p.746 - 752, 1999/07
no abstracts in English
Kusama, Yoshinori; JT-60 Team
Physics of Plasmas, 6(5), p.1935 - 1942, 1999/05
Times Cited Count：17 Percentile：50.4(Physics, Fluids & Plasmas)no abstracts in English
Fukuda, Takeshi; JT-60 Team
Fusion Engineering and Design, 46(2-4), p.337 - 345, 1999/00
Times Cited Count：7 Percentile：49.64(Nuclear Science & Technology)no abstracts in English
