(1)Guy's and St Thomas' NHS Foundation Trust, Medical Physics, LONDON, United Kingdom;

¹Erasmus Medical Centre, Otorhinolaryngology and Head and Neck Surgery, Rotterdam, The Netherlands

(1)Aarhus University Hospital, Department of Oncology, Aarhus, Denmark;(2)Medical University/General Hospital of Vienna, Department of Radiation Oncology- Comprehensive Cancer Center, Vienna, Austria;(3)Gustave-Roussy, Department of Radiotherapy, Villejuif, France;(4)Tata Memorial Hospital, Department of Radiation Oncology, Mumbai, India;(5)University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands;(6)Mount Vernon Hospital, Mount Vernon Cancer Centre, Northwood, United Kingdom;(7)Institute of Oncology Ljubljana, Department of Radiotherapy, Ljubljana, Slovenia;(8)Postgraduate Institute of Medical Education and Research, Department of Radiotherapy and Oncology, Chandigarh, India;(9)The Radium Hospital- Oslo University Hospital, Department of Oncology, Oslo, Norway;(10)Cross Cancer Institute and University of Alberta, Department of Oncology, Edmonton, Canada;(11)Radiotherapiegroep Arnhem, Department of Radiotherapy, Arnhem, The Netherlands;(12)St James's University Hospital, Leeds Cancer Centre, Leeds, United Kingdom;(13)UZ Leuven, Department of Radiation Oncology, Leuven, Belgium;(14)St. Olavs Hospital, Clinic of Oncology and Women's Clinic, Trondheim, Norway;(15)Amsterdam University Medical Centers- University of Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands;(16)Leiden University Medical Center, Department of Radiation Oncology, Leiden, The Netherlands;

(1)The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Medical Physics, London, United Kingdom;

(1)Hunan Cancer Hospital- the Affiliated Cancer Hospital of Xiangya Medical School- Central South University, Head and Neck Radiotherapy Department, ChangSha, China;(2)Unity Hospital- Rochester Regional Health, Internal Medicine, Rochester, USA;(3)University of Texas- MD Anderson Cancer Center, Radiation Oncology, Texas, USA;(4)Zhejiang Cancer Hospital, Thoracic Radiotherapy Department, Hangzhou, China;(5)King Chulalongkorn Memorial Hospital, Radiotherapy Department, Bangkok, Thailand;

(1)IEO- European Institute of Oncology IRCCS, Division of Radiotherapy, Milan, Italy;(2)IEO- European Institute of Oncology IRCCS, Department of Medical Physics, Milan, Italy;(3)IEO- European Institute of Oncology IRCCS, Scientific Directorate, Milan, Italy;(4)Associazione Italiana di Radioterapia Oncologica, Airo, Milan, Italy;