1. Department of Gamma Knife Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, P.R. China
2. Department of Neurosurgery, Beijing Neurosurgical Institute, Beijing 100050, P.R. China
3. Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing 100050, P.R. China
4. Department of Neuropathology, Beijing Neurosurgical Institute, Beijing 100050, P.R. China
5. Department of Radiotherapy, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China