1. Department of Internal Medicine, Harbin Medical University Cancer Hospital, Harbin Medical University, Harbin, Heilongjiang 150081, China
2. Department of Geriatrics, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150086, China
3. Department of Gastroenterology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang 150086, China
4. Department of Nuclear Medicine, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, China
5. Institute of Intensive Care Unit, Heilongjiang Academy of Medical Science, Harbin, Heilongjiang 150081, China