1. Department of Radiation Oncology, CyberKnife Center, & Key Laboratory of Cancer Prevention & Therapy, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center for Cancer, Tianjin 300060, PR China
2. Department of Radiation Oncology, Fox Chase Cancer Center, PA 19111, USA
3. Department of Thoracic Cancer & Huaxi Student Society of Oncology Research, West China Hospital, West China School of Medicine, Sichuan University, Sichuan Province 610041, PR China
4. Current address: Division of Radiation & Cancer Biology, & Department of Radiation Oncology, Stanford University School of Medicine, CA 94305, USA