1. Department of Oral and Maxillofacial Surgery, Faculty of Life Sciences Kumamoto University, Kumamoto, Japan
2. Department of Radiation Oncology Kumamoto University Hospital, Kumamoto, Japan
3. Department of Medical Imaging, Faculty of Life Sciences Kumamoto University, Kumamoto, Japan
4. Radiation Biology and Medicine, Faculty of Medicine Tohoku Medical and Pharmaceutical University, Sendai, Japan
5. Department of Molecular Pathology Tokyo Medical University, Tokyo, Japan