1. Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
2. Department of Radiology and Radiation Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
3. Department of Radiation Oncology, Kanagawa Cancer Center, Kanagawa, Japan
4. Gunma Heavy-ion Medical Center, Gunma University, Gunma, Japan
5. Department of Radiation Oncology, University of Tsukuba Faculty of Medicine, Ibaraki, Japan
6. Department of Radiology, Jichi Medical University, Tochigi, Japan
7. Japan Community Health Care Organization Tokyo Shinjuku Medical Center, Tokyo, Japan
8. Department of Urology, Graduate School of Medicine, Chiba University, Chiba, Japan