1. Department of Radiology, University of Occupational and Environmental Health, Kitakyusyu City, Japan;
2. Department of Radiology, Kansai Medical University, Moriguchi City, Japan;
3. Cancer Therapy Centre, Tobata Kyoritsu Hospital, Kitakyusyu City, Japan;
4. Department of Radiation Oncology, University of Tsukuba, Tsukuba City, Japan;
5. Department of Radiation Oncology, Gunma University Heavy Ion Medical Centre, Maehashi City, Japan;
6. Department of Radiology, National Hospital Organization Kagoshima Medical Centre, Kagoshima City, Japan;
7. Department of Radiology, National Hospital Organization Minami Wakayama Medical Centre, Tanabe City, Japan;
8. Department of Radiation Oncology, Osaka City General Hospital, Osaka City, Japan;
9. Department of Radiology, Harasanshin Hospital, Fukuoka City, Japan