1. Department of Radiation Oncology, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Yonsei University College of Medicine, Seoul, Korea.
3. Department of Radiation Oncology, Kyung Hee University School of Medicine, Seoul, Korea.
4. Department of Radiation Oncology, Soonchunhyang University College of Medicine, Asan, Korea.
5. Department of Radiation Oncology, University of Ulsan College of Medicine, Ulsan, Korea.
6. Department of Radiation Oncology, Korea University College of Medicine, Seoul, Korea.
7. Department of Radiation Oncology, Dongguk University College of Medicine, Seoul, Korea.
8. Department of Radiation Oncology, NHIC Ilsan Hospital, Goyang, Korea.
9. Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
10. Proton Therapy Center National Cancer Center, Goyang, korea.
11. Department of Radiation Oncology, Konkuk University School of Medicine, Seoul, Korea.