1. Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Radiation Oncology, Dongnam Institute of Radiological and Medical Sciences, Busan, Korea.
3. Department of Radiation Oncology, Asan Medical Center, Seoul, Korea.
4. Department of Radiation Oncology, Samsung Medical Center, Seoul, Korea.
5. Department of Radiation Oncology, Yeungnam University College of Medicine, Daegu, Korea.
6. Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Huasun, Korea.