Health Risks of Low Dose-Rate and Low Dose Radiation Exposures

Abstract

The Fukushima-Daiichi nuclear power plant disaster resulted in environmental contamination by released fission products broadly in eastern Japan, as well as arising much interest and anxiety on the health risks of low dose-rate and low dose radiation exposures due to radioactivity present in their residential environments. This paper describes a concept on the risk of radiation carcinogenesis, together with its uncertainties, and annual dose-limits as a guideline of radiation protection for radiation workers and publics under normal or emergency conditions. Finally, estimates of cancer risks due to long-term low dose-rate and low dose radiation exposures less than 100 mSv or 100 mGy are provided by using experimental data actually obtained both from long-term external exposure of mice to low dose-rate gamma-rays, and from persistent internal exposure of rats and mice to alpha-particles emitted from plutonium compounds.