1. Department of Radiation Oncology; Uludag University Faculty of Medicine; Bursa Turkey
2. Department of Radiation Oncology; University of Michigan; Ann Arbor Michigan
3. Department of Radiation Oncology; Saint Savvas Anticancer Institute of Athens; Greece
4. Division of Oncology; Institute of Radiation Therapy, Tel-Aviv Sourasky Medical Center; Tel Aviv Israel
5. Department of Otolaryngology-Head and Neck Surgery; University of Michigan; Ann Arbor Michigan
6. Division of Hematology Oncology; Department of Internal Medicine; University of Michigan Health System; Ann Arbor Michigan
7. Department of Biostatistics; University of Michigan; Ann Arbor Michigan
8. Department of Pathology; University of Michigan; Ann Arbor Michigan