1. Research Institute of Clinical Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
2. Department of Radiation Oncology, Kyung Hee University Hospital, Seoul, Korea.
3. Department of Radiological & Medico Oncological Sciences, University of Science and Technology, Seoul, Korea.
4. Division of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
5. Department of Radiation Oncology, School of Medicine, Yonsei University, Seoul, Korea.
6. Department of Radiation Oncology, Inje University Ilsan Paik Hospital, Goyang, Korea.
7. Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.