1. Department of Health Management Center, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
2. Department of Infectious Diseases, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
3. Department of Radiotherapy, Hunan Cancer Hospital, Changsha, Hunan 410013, P.R. China