1 Department of Radiation Oncology, Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, Republic of Korea.
2 Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea.
3 Department of Neurosurgery, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea.
4 Department of Orthopedic Surgery, Korea Institute of Radiological and Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul, 01812, Republic of Korea. cbkongmd@gmail.com.