1. Department of Radiation Oncology Niigata University Medical and Dental Hospital Niigata Japan
2. Department of Radiological Technology Niigata University Graduate School of Health Sciences Niigata Japan
3. Department of Radiology and Radiation Oncology Niigata University Graduate School of Medical and Dental Sciences Niigata Japan
4. Department of Radiology, Division of Radiation Oncology Yamagata University Faculty of Medicine Yamagata Japan
5. Section of Radiology, Department of Clinical Support Niigata University Medical and Dental Hospital Niigata Japan