1. Department of Radiation Oncology, The Catholic University of Korea, Seoul, Korea.
2. Department of Diagnostic Radiology, The Catholic University of Korea, Seoul, Korea.
3. Department of Clinical Pathology, The Catholic University of Korea, Seoul, Korea.
4. Department of Head & Neck Surgery, The Catholic University of Korea, Seoul, Korea.
5. Department of Medical Oncology, The Catholic University of Korea, Seoul, Korea.