1. Department of Radiotherapy, Hebei Medical University Fourth Affiliated Hospital/Hebei Provincial Tumor Hospital, Shijiazhuang, Hebei 050011, P.R. China
2. Department of Oncology, Hebei General Hospital, Shijiazhuang, Hebei 050011, P.R. China
3. Department of CT and MRI, Hebei Medical University Fourth Affiliated Hospital/Hebei Provincial Tumor Hospital, Shijiazhuang, Hebei 050011, P.R. China