1. Department of Radiation Sciences, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Aomori 036‑8564, Japan
2. Department of Radiological Technology, Hirosaki University School of Health Sciences, Hirosaki, Aomori 036‑8564, Japan
3. Department of Radiation Oncology, Graduate School of Medicine, Hirosaki University, Hirosaki, Aomori 036‑8562, Japan