1 Joint Department of Physics at The Royal Marsden NHS Foundation Trust and Institute of Cancer Research, London, UK.
2 Oncology Centre, Colchester Hospital University NHS Trust, Colchester, UK.
3 Faculty of Health Sciences, University of Southampton, Southampton, UK.
4 ICR-CTSU, Institute of Cancer Research, Sutton, UK.
5 Oncology Centre, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
6 Centre for Vision Speech and Signal Processing, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK. Electronic address: p.evans@surrey.ac.uk.