1 Department of Radiology, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
2 Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Rickmansworth Road, Northwood, Middlesex, HA6 2RN, UK. anwar.padhani@stricklandscanner.org.uk.
3 Molecular Imaging Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
4 Division of Surgery, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK.