1. Department of Radiation Oncology, Nippon Medical School, Tamanagayama Hospital, Nagayama, Tama, Tokyo, Japan
2. Department of Radiation Oncology, University Hospital, Kyoto Prefectural University of Medicine, Kajii-cho,Kawaramachi-Hirokoji, Kamigyo, Kyoto, Kyoto, Japan
3. Department of Radiology, Kaizuka City Hospital, Hori, Kaizuka, Osaka, Japan
4. Department of Radiology, Nippon Medical School Hospital, Sendagi,Bunkyo, Tokyo, Japan