1. Food Safety Commission, Cabinet Office, Government of Japan, Akasaka Park Building 22F, 5-2-20 Akasaka, Minato-ku, Tokyo 107-6122 Japan
2. Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 Japan