1. Department of Radiation Oncology Hokkaido University Hospital Sapporo Japan
2. Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI‐CoRE) Hokkaido University Sapporo Japan
3. Department of Radiation Medicine, Faculty of Medicine Hokkaido University Sapporo Japan
4. Department of Statistical Data Science The Institute of Statistical Mathematics Tokyo Japan
5. Department of Radiation Medical Science and Engineering, Graduate School of Medicine Hokkaido University Sapporo Japan