1. Department of Radiology Nagoya City University Graduate School of Medical Sciences 1 Kawasumi, Mizuho‐cho, Mizuho‐ku Nagoya 467‐8601 Japan
2. Department of Radiation Oncology Nanbu Tokushukai Hospital 171‐1 Hokama, Yaese‐cho Simajiri‐gun Okinawa 901‐0493 Japan
3. Department of Urology Nanbu Tokushukai Hospital 171‐1 Hokama, Yaese‐cho Simajiri‐gun Okinawa 901‐0493 Japan