1. Department of Therapeutic Radiology, Tokushima University Graduate School , Japan, 3-18-15, Kuramoto-cho, Tokushima-shi, Tokushima 770-8503 , Japan
2. Department of Radiation Oncology, Ise Red Cross Hospital , Japan, 1-471-2, Funae, Ise-shi, Mie 516-8512 , Japan
3. Department of Radiation Oncology, Saitama Medical University, International Medical Center , Japan, 1397-1, Yamane, Hidaka-shi, Saitama 350-1298 , Japan
4. Department of Radiology, Kyoto Prefectural University of Medicine , Japan, Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566 , Japan
5. Department of Radiation Oncology, Juntendo University Graduate School of Medicine , Japan, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421 , Japan
6. Department of Radiology, Kansai Medical University Medical Center , Japan 2-5-1, Shin-machi, Hirakata-shi, Osaka 573-1010 , Japan
7. Diagnostic Radiology and Radiation Oncology , Graduate School of Medicine, , Japan, 1-8-1, Inohara, Chuo-ku, Chiba-shi, Chiba 260-8670, Japan
8. Chiba University , Graduate School of Medicine, , Japan, 1-8-1, Inohara, Chuo-ku, Chiba-shi, Chiba 260-8670, Japan
9. Department of Radiological Technology, Teikyo University Graduate School of Medicine , Japan, 6-22, Misakimachi, Omuta-shi, Fukuoka 836-8505 , Japan
10. Department of Radiation Oncology, Saitama Prefectural Cancer Center , Japan, 1696, Itai, Kumagaya-shi, Saitama 360-0197 , Japan
11. Department of Radiology, Mie University Graduate School of Medicine , Japan, 2-174, Edobashi, Tsu-shi, Mie 5148-507 , Japan
12. Radiation Therapy Center, Okinawa Chubu Hospital , Japan, 281, Miyasato, Uruma-shi, Okinawa 904-2293 , Japan
13. Department of Radiation Oncology, Gunma University Graduate School of Medicine , Japan, 3-39-22, Showa-machi, Maebashi-shi, Gunma 371-8511 , Japan
14. Department of Radiation Oncology, University of Tsukuba , Japan, 1-1-1, Tennoudai, Tsukuba-shi, Ibaraki 305-8575 , Japan
15. Department of Radiology , Faculty of Medicine, , Japan, 4-4-37, Takeda, Kofu-shi, Yamanashi 400-8510 , Japan
16. University of Yamanashi , Faculty of Medicine, , Japan, 4-4-37, Takeda, Kofu-shi, Yamanashi 400-8510 , Japan