1. Department of Clinical Oncology, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
2. Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
3. Department of Radiotherapy Dosimetry, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
4. Department of Radiation Oncology, Hacettepe University, Ankara, Turkey
5. The Royal Marsden NHS Foundation Trust, London, United Kingdom