1. Department of Therapeutic Radiology and Oncology, Kyoto University Graduate School of Medicine, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
2. Department of Radiation Oncology, Katsura Hospital, 17 Yamadahirao-cho, Nishigyo-ku, Kyoto 615-8256, Japan
3. Department of Radiation Oncology, National Hospital Organization Kyoto Medical Center, 1-1 Hukakusa Mukoubatake-cho, Ukyo-ku, Kyoto 612-0861, Japan