1. Department of Radiology, School of Medicine, University of Yamanashi, Yamanashi, Japan
2. Department of Radiology, School of Medicine, University of Tokyo, Tokyo, Japan
3. Department of Radiology, Toho University Omori Medical Center, Tokyo, Japan
4. Department of Radiation Medicine, Faculty of Medicine, Hokkaido University, Sapporo, Japan
5. Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Japan
6. Ion Beam Therapy Center, SAGA-HIMAT Foundation, Tosu, Japan
7. Department of Radiation Oncology, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan
8. Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
9. Department of Radiation Oncology, Funabashi Municipal Medical Center, Funabashi, Japan