Anwar R Padhani1, Giuseppe Petralia2, Francesco Sanguedolce3. 1. Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Middlesex, UK. Electronic address: anwar.padhani@stricklandscanner.org.uk. 2. Division of Radiology, IEO - European Institute of Oncology, Milan, Italy. 3. Northampton General Hospital, NHS Trust, Northampton, UK; King's College Hospital, NHS Foundation Trust, London, UK.