1. Kobe City Medical Center General Hospital Department of Radiation Oncology, , Minamimachi 21-1, Minatojima, Chuo-ku, Kobe 650-0047, Hyogo, Japan
2. Kyoto University Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, , 54 Shogoin-Kawahara-cho, Sakyo-ku, 606-8507, Kyoto, Japan
3. Osaka Red Cross Hospital Department of Radiation Oncology, , 5-30 Fudegasaki-cho, Tennoji-ku, 543-8555, Osaka, Japan
4. Kindai University Department of Radiation Oncology, Faculty of Medicine, , 377-2, Ohno-Higashi, Osaka-Sayama, 589-8511, Osaka, Japan