[1] Royal Marsden NHS Fdn Trust, Joint Dept Phys, London, England
[2] Inst Canc Res, London SW3 6JB, England
[3] Colchester Hosp Univ NHS Trust, Ctr Oncol, Colchester, Essex, England
[4] Univ Southampton, Fac Hlth Sci, Southampton, Hants, England
[5] Inst Canc Res, ICR CTSU, Sutton, Surrey, England
[6] Cambridge Univ Hosp NHS Fdn Trust, Ctr Oncol, Cambridge, England
[7] Univ Surrey, Fac Engn & Phys Sci, Ctr Vis Speech & Signal Proc, Guildford GU2 5XH, Surrey, England