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Furuta, Hiroshige*; Sato, Kaoru; Nishide, Akemi*; Kudo, Shinichi*; Saigusa, Shin*
Health Physics, 121(5), p.471 - 483, 2021/11
Times Cited Count：1 Percentile：16.35(Environmental Sciences)Low dose radiation induced "health effects" containing cancer risk for a Japanese radiation worker cohort is epidemiologically evaluated using the personal dose equivalent (Hp(10)). On the other hand, Hp(10) is not recommended for epidemiological evaluation of cancer risks, since the Hp(10) is widely used for radiological protection purposes. In addition, the cancer risk depends on organ doses rather than Hp(10). Thus, we developed a new method for estimating organ doses from Hp(10) of radiation workers. The developed method enables epidemiological analysis against Japanese radiation workers by considering the response characteristics of personal dosimeters, exposure geometry and energy, and body size of radiation workers in Japan. In the future, we will reconstruct organ dose conversion factor and will evaluate the risk of cancer mortality and morbidity using the organ dose in Japan.
Shimada, Kazumasa; Kai, Michiaki*
Journal of Radiation Protection and Research, 46(3), p.83 - 97, 2021/09
[Background] The lifetime risk of lung cancer incidence owing to radiation for non-smokers is overestimated because the average cancer baseline among a population including smokers is used. In recent years, the generalized multiplicative (GM) excess relative risk (ERR) model has been developed in the life span study of atomic bomb survivors to consider the joint effect of radiation and smoking. Based on this background, the issues of radiation risk assessment considering smoking will be discussed in this paper in 2 parts. [Materials and Methods] Part 1: We proposed a simple method of estimating the baseline risk for non-smokers using current smoking data. We performed sensitivity analysis on baseline risk estimation to discuss the birth cohort effects of birth year effect and smoking history. Part 2: We applied the GM ERR model for Japanese smokers to calculate lifetime attributable risk (LAR). We also performed a sensitivity analysis with other ERR models (e.g., simple additive (SA) ERR model). [Results] Part 1: The lifetime baseline risk (LBR) for non-smokers were 54% (44% - 60%) or males and 24% (18% - 29%) for females, which were lower than the LBRs for all adults including smokers. Part 2: When comparing the LAR between the SA ERR model and the GM ERR model, if the radiation dose was 
200 mGy or less, the difference between these ERR models was within the standard deviation of the LAR owing to the uncertainty of the smoking information.
Takahara, Shogo; Iijima, Masashi; Shimada, Kazumasa
Hoken Butsuri, 50(3), p.172 - 181, 2015/09
Ouchi, Noriyuki
Hoken Butsuri, 40(2), p.166 - 169, 2005/06
Development of the new mathematical model of the carcinogenesis in a low dose in mind is reported. The new model which describes from cell canceration to the tumorigenesis in consideration of the physical dynamics of a cell level was built. In a cell group level, it has both intra-cellular dynamics, such as mutation, cell division, and cell death, and physical dynamics such as, adhesion between cells, modification, and movement, and a model can investigate with time that tumor is formed.
transformation; Article reviewSaigusa, Shin*
JAERI-Review 2002-009, 43 Pages, 2002/03
JAERI-Review-2002-009.pdf:2.3MB
The mechanism of the process of radiation-induced transformation that leads normal mammalian cell to malignant feature is still not clear. However, a drastic development of molecular biological technique in medical biology research field since 1990's have progressively revealed the mechanisms of this process and recent results have been starting to incorporate in the recent radiation risk estimate procedures. This report describes the results of the survey and review of the articles concerned with experimental studies of radiation induced in vitro transformation, since 1993 to 1997.
Onodera, Junichi
Enerugi Rebyu, 21(7), p.23 - 26, 2001/07
no abstracts in English
Shimada, Kazumasa
no journal, ,
Cancer risk assessment of radiation is used a dose response based on epidemiology data. To develop more scientific and reasonable risk assessment, it is important to introduce cancer model considering cell mutation to risk assessment. However, it is not easy to gain cell mutation parameters by experiments. In this research, I used the State Space Model to combine the epidemiology data of atomic bomb survivor and cancer model considering cell mutation to calculate model parameters each radiation doses and ages.
Shimada, Kazumasa; Kai, Michiaki*
no journal, ,
In this study, we proposed that Disability-Adjusted Life Year (DALY) to estimate radiation cancer risk in Japanese residents. Lifetime cancer mortality, incidence rate, and lives lost have been the previous indices of health risk associated with radiation protection. ICRP defined the detriment in Publication 60 by considering non-fatal cancers and the number of lives lost due to the difference in latent times. However, the detriment has the disadvantage that it can neither be appropriately interpreted nor used. Therefore, the common index is required to discuss health risk of radiation and the others. As a risk measure of both common health and environmental health, there is a disability-adjusted life year (DALY) that is developed from concepts of life lost. DALY was developed by Harvard University in 1990 and was further adopted to establish an order of priority for health issues by the World Health Organization (WHO). In this study, we calculated DALY to estimate radiation cancer risk and compared this with the radiation detriment to discuss the effectiveness of DALY.
Yokoya, Akinari; Kaminaga, Kiichi; Hattori, Yuya; Watanabe, Ritsuko; Noguchi, Miho; Fujii, Kentaro
no journal, ,
no abstracts in English
