1. Department of Gastroenterology, The First People's Hospital of Xuzhou, Xuzhou Municipal Hospital Affiliated to Xuzhou Medical University, Xuzhou, Jiangsu 221002, P.R. China
2. Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions and School of Radiation Medicine and Protection, Medical School of Soochow University, Suzhou, Jiangsu 215123, P.R. China
3. Department of Gastroenterology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu 214023, P.R. China
4. State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, Jiangsu 215123, P.R. China