1. Department of Cardiac and Vascular Sciences (Dermatology), St George's Hospital, University of London, Cranmer Terrace, London SW17 0RE, U.K.
2. Nuclear Medicine Unit, Department of Imaging, Hammersmith Hospital, Du Cane Road, London W12 0HS, U.K.
3. Department of Nuclear Medicine, Royal Sussex County Hospital, Eastern Road, Brighton, East Sussex BN2 5BE, U.K.
4. Department of Basic Medical Sciences (Physiology), St George's Hospital, University of London, Cranmer Terrace, London SW17 0RE, U.K.