Dept. of Radiation Effects Research

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 Activities involving radiation must be regulated based on scientific evidence to ensure safety. Effective regulation requires knowledge of radiation biology, particularly the quantitative relationship between the extent of radiation exposure and resulting health effects, and underlying mechanisms. The importance of such information has been highlighted once again following the accident at the Fukushima Daiichi Nuclear Power Plant.
 For the past decade, QST-NIRS has been using animal and cell experiments to investigate how individual factors, including age and lifestyle, modify radiation-associated cancer risk. This research is continuing to provide insights into radiation-induced cancer mechanisms using cutting-edge research techniques. Integration of existing data gathered from studies of human populations with experimental data from our project where we explore important exposure parameters, will contribute to a more rigorous and scientifically-grounded system of radiation protection.

Research Theme

Exploring the mechanisms of radiation carcinogenesis with the latest scientific advances

At low levels of radiation exposure, the risk of radiation-induced cancer is the health consequence of most concern. Radiation is known to cause cancer primarily through unrepaired or misrepaired DNA damage, resulting in cancer-initiating mutations. Knowing which genes and cell types are at risk is a vital foundation for a science-based radiation protection system and the goal of developing countermeasures to reduce radiation risks. We use cutting-edge techniques such as next-generation sequencing and the latest stem cell biology to generate novel and relevant scientific advances in radiation carcinogenesis.

 

Investigating how lifestyle modifies radiation effects

It is likely that the effects of radiation can be modulated by stress as well as a wide range of individual lifestyle factors, with tobacco smoking a well-studied example. Moreover, ongoing changes in the workplace as well as in home and family life provide new challenges to estimating radiation-associated risk at the individual level. We investigate the effects of various lifestyle factors including various stresses and dietary habits on the risk and mechanisms of radiation-induced biological effects such as carcinogenesis at the molecular, cellular and whole-body level in animals to provide new strategies for reducing radiation risk.

Research on the effect of low dose-rate radiation exposure through animal experiments

We are conducting experiments where mice are continuously gamma-irradiated at low dose rate during juvenile or adult periods and monitored to measure life-shortening and the incidence of leukemia and solid cancers (Figure 1). Parallel experiments on the induction of mammary tumors and brain tumors are also being undertaken. The survival and cancer incidence data from such experiments will be used as evidence of the age dependence of the dose rate effect.

Construction of a Radiobiological Archive of Animal Experiments (J-SHARE)

We launched a project called ‘Radiobiology for Children’s Health’ in 2004 to evaluate the effects of radiation on children, particularly from low-dose exposure, which has since focused on risk analyses for life-shortening and cancer prevalence using laboratory animals. Genetic and epigenetic alterations in radiation-induced tumors have also been analyzed, with the aim to better understand mechanisms of radiation carcinogenesis, particularly those specific to childhood exposures. We have since launched a project to archive the information/biomaterials obtained from our research (‘Japan-StoreHouse of Animal Radiobiology Experiments’, or J-SHARE). In the future, we will continue adding to J-SHARE by making it available to research institutions inside and outside Japan through cooperation and joint research with similar archives in the U.S. and in Europe to maximize the results of radiation effects research.

Research Team

  • Radiobiology for Children's Health Research Team
  • Stem Cells and Cancer Research Team
  • Chronic Exposure, Cancer and Pathology Research Team
  • Stress and Lifestyle Effects Research Team
  • Dietary Effects Research Team

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4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan Tel: +81-43-206-3025 (outside of Japan), or 043-206-3025 (in Japan)