1. Department of Radiation Oncology Radboud University Medical Center Nijmegen the Netherlands
2. Department of Operating Rooms Radboud University Medical Center Nijmegen the Netherlands
3. Department of Otolaryngology – Head and Neck Surgery Radboud University Medical Center Nijmegen the Netherlands
4. Department of Head and Neck Surgical Oncology University Medical Center Utrecht Utrecht the Netherlands
5. Department of Radiation Oncology Netherlands Cancer Institute/Antoni van Leeuwenhoek Amsterdam the Netherlands