1. Department of Radiation Measurement and Dose Assessment, National Institutes for Quantum and Radiological Sciences and Technology, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-city, Chiba, Japan
2. Department of Radiology, Self-Defense Forces Central Hospital, 1-2-24 Ikejiri, Setagaya-ku, Tokyo, Japan
3. Department of Environment Systems, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-City, Chiba, Japan