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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.
Kobayashi, Yasuhiko
Kaiyo To Seibutsu, 36(3), p.269 - 276, 2014/06
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.
Pinak, M.
Radiation Risk Assessment Workshop Proceedings, p.30 - 39, 2001/00
no abstracts in English
Yamazawa, Hiromi; Amano, Hikaru
Genshiryoku Kogyo, 42(8), p.49 - 53, 1996/00
no abstracts in English
Isotope News, 0(487), p.28 - 29, 1995/01
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. DALY is calculated as the sum of Years of Life Lost (YLL) and Years Lived with Disability (YLD). We separately calculated the excess absolute risk for cancer incidence based on the Excess Relative Risk (ERR) and Excess Absolute Risk (EAR) models. Cancer-specific incidence, mortality rates, and the survival fractions exceeding 5 years have been based on data from the National Cancer Center in Japan. The cancer-specific incidence and mortality rate statistics were from 2010 in Japan; the survival fractions exceeding 5 years were from 2003 to 2005 in Japan. We used disability weights (DW) of cancer according to stage diagnosis/therapy in the WHO table. Table illustrates the results of DALY for each cancer site for Japanese after exposure at 1 Gy dose per 1000 persons. Furthermore, the ratio of DALY for each cancer site per DALY for all solid cancers and the ratio of YLL per DALY for each cancer are shown in this Table. We calculated the DALY of radiation solid cancer risk as a measure of health risk. DALY can be a practical tool that can compare many types of diseases encountered in common public health.
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.
Shimada, Kazumasa; Kai, Michiaki*
no journal, ,
This paper describes lung cancer mortality risks due to radiation exposure considering the history of smoking in Japanese people. In this study, we calculated the DALY of lung cancer mortality for Japanese males considering the joint effects of radiation and smoking using the generalized multiplicative excess relative risk interaction model (GM model). First, we estimated the lung cancer baseline risk for non-smokers to divide the risk of smoking for mixed population groups that include smokers and non-smokers. Second, we developed a radiation risk model from single to chronic exposure to be able to evaluate the risk of cancer in existing and control exposure situations. Forth, the maximum relative risks of lung cancer mortality for smokers and non-smokers induced by a radiation exposure of 20 mGy/y for Japanese smokers between the age of 20 and 60 years were calculated using the GM model to be 22.2 for men and 15.7 for women, respectively. Therefore, our calculations show that only considering radiation risks strongly underestimate the real risk of lung cancer when the smoking history is not taken into account. Our study indicates that estimations of the health risk due to radiation exposure should consider not only age and gender but also the history of smoking for deriving an occupational exposure limit.
Shimada, Kazumasa; Kai, Michiaki*
no journal, ,
The latest atomic bomb survivor life span study (LSS) reported that cancer risks due to radiation are increased with smoking synergistically. Therefore, it is important for radiation risk estimation to consider the information of smoking habit. However, current method of radiation risk estimation are not considered with age and sex but considered with smoking habit. Then, this method may overestimate the risk of radiation for non-smokers. For this reason, we estimate cancer risk due to radiation considering smoking cohort effect (information of smoking rate and quitting smoking) and evaluate the effects of smoking information for risk evaluation. In this research, it is important for estimation of non-smoker baseline risk to consider the information of smoking habit for over 50 years old when their cancer risk increase.
Sakai, Kazuo*; Yamada, Yu*; Yoshida, Kazuo*; Yoshinaga, Shinji*; Sato, Kaoru; Ogata, Hiromitsu*; Iwasaki, Toshiharu*; Kudo, Shinichi*; Asada, Kyosei*; Kawaguchi, Isao*; et al.
no journal, ,
Task Group of Low dose and Low Dose Rate Radiation Risk Estimation Method in the Japan Health Physics Society presented the task group activity from April, 2016 to March, 2018. The presenter introduce the current status and issues of dose assessment (e.g. effects of anatomical characteristics of subjects, monitoring data, distribution of dose and dose rate in body on uncertainty of dose assessment).
