1. Department of Radiation Oncology, Kumamoto University Hospital, Kumamoto, Japan
2. Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
3. Department of Medical Imaging, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
4. Department of Otolaryngology–Head and Neck Surgery, Kumamoto University Hospital, Kumamoto, Japan
5. Department of Radiology, Japanese Red Cross Kumamoto Hospital, Kumamoto, Japan
6. Department of Radiology, Saiseikai Kumamoto Hospital, Kumamoto, Japan
7. Department of Diagnostic Radiology, Kumamoto University Hospital, Kumamoto, Japan