1. Department of Radiation Oncology, Hokkaido University Faculty of Medicine, Hokkaido, Japan
2. Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Hokkaido, Japan
3. Department of Radiation Oncology, Hokkaido University Hospital, Hokkaido, Japan
4. Department of Medical Physics, Hokkaido University Hospital, Hokkaido, Japan
5. Department of Radiation Medical Science and Engineering, Hokkaido University Faculty of Medicine, Hokkaido, Japan
6. Department of Gastroenterology and Hepatology, Hokkaido University Faculty of Medicine, Hokkaido, Japan
7. Department of Gastroenterological Surgery I, Hokkaido University Faculty of Medicine, Hokkaido, Japan
8. Global Center for Biomedical Science and Engineering, Hokkaido University Faculty of Medicine, Hokkaido, Japan