1. Tianjin Medcical University Cancer Institute and Cancer Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, P.R. China
2. Department of Radiotherapy Oncology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an 710061, Shaanxi, P.R. China
3. The Gao Qing People's Hospital of Zibo, Zibo 255000, Shandong, P.R. China