1. Advanced Radiotherapy Group, Patrick G. Johnston Centre for Cancer Research, Queen’s University Belfast , Belfast, Belfast, BT97 1NN, United Kingdom
2. Department of Imaging Services, Belfast Health & Social Care Trust , Belfast, BT9 7AB, United Kingdom
3. Department of Radiological Imaging & Protection Service, Regional Medical Physics Service, Belfast Health & Social Care Trust , Belfast, BT9 7AB, United Kingdom
4. Department of Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust , Belfast, BT9 7AB, United Kingdom
5. St Luke’s Cancer Centre, The Royal Hospital , Egerton Rd, Guildford GU2 7XX, United Kingdom
6. Department of Clinical Oncology, Northern Ireland Cancer Centre, Belfast Health and Social Care Trust , Belfast, BT9 7AB, United Kingdom