1. Baskent University Medical Faculty, Department of Radiation Oncology, Adana, Turkey
2. Nicosia Dr. Burhan Nalbantoglu Goverment Hospital, Radiation Oncology Clinics, Nicosia, Turkish Republic of Northern Cyprus
3. Adana City Hospital, Clinics of Otolaryngology, Adana, Turkey
4. Baskent University Medical Faculty, Department of Medical Oncology, Adana, Turkey
5. Koc University, School of Medicine, Department of Radiation Oncology, Istanbul, Turkey
6. The University of Texas, MD Anderson Cancer Center, Department of Radiation Oncology, Houston, TX, USA