[Ingestion of contaminated foods and drinks and internal radiation].

Many international agencies have evaluated radiation effects to humans. However, reports on effects of international radiation are not so many. Internal exposure of radiation depends on both physical and chemical properties of the radioactive material. Therefore, we combine several methods for the exposure estimation, including environmental measurements and questionnaires to individual subjects. Then, we must select quantitative effect estimates from actual case examples of internal radiation including all age strata, especially children. Among the residents exposed to radiation from the Chernobyl accident in 1986, increased incidence of thyroid cancer and leukemia has been reported. Quantitative effect estimates were also presented in some of the reports. The estimates may be also useful for individual protection for the Fukushima case.