1 Department of Clinical Oncology, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK. Electronic address: Shahid.iqbal@nhs.net.
2 Department of Radiotherapy Physics, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK. Electronic address: David.morgan8@nhs.net.
3 Department of Radiotherapy Physics, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK. Electronic address: Nick.west@nhs.net.
4 Department of Clinical Oncology, Beatson West of Scotland Cancer Center, Glasgow, UK. Electronic address: Claire.paterson2@ggc.scot.nhs.uk.