1. Department of Surgery, Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, Sichuan 610051, P.R. China
2. Radiation Medicine Department of Institute of Preventive Medicine, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
3. Laboratory of Radiation Medicine, West China School of Basic Medical Sciences and Forensic Medicine, Chengdu, Sichuan 610041, P.R. China