1. Seoul and Daejeon, Korea
2. Departments of Otolaryngology-Head and Neck Surgery, Cancer Research Institute, and Clinical Research Institute, Seoul National University College of Medicine, Seoul
3. Departments of Otolaryngology-Head and Neck Surgery and Cancer Research Institute College of Medicine, Chungnam National University, Daejeon
4. Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul