1. Department of Radiation Oncology, Ewha Womans University College of Medicine, Seoul, Korea.
2. Department of Radiation Oncology, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
3. Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
5. Proton Therapy Center, National Cancer Center, Goyang, Korea.
6. Center for Breast Cancer, National Cancer Center, Goyang, Korea.
7. Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
8. Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
9. Department of Radiation Oncology, Yeungnam University College of Medicine, Daegu, Korea.
10. Department of Radiation Oncology, Kyungpook National University School of Medicine, Daegu, Korea.
11. Department of Radiation Oncology, Pusan National University School of Medicine, Busan, Korea.