1. Oncology Center Osaka University Hospital Suita Osaka 565‐0871 Japan
2. Suita Tokushukai Hospital Suita Osaka 565‐0814 Japan
3. Division of Health Sciences Osaka University Graduate School of Medicine Suita Osaka 565‐0871 Japan
4. Department of Radiation Oncology Osaka University Graduate School of Medicine Suita Osaka 565‐0871 Japan
5. Department of Carbon Ion Radiotherapy Osaka University Graduate School of Medicine Suita Osaka 565‐0871 Japan