1. Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ (UK), Fax: (+44) 20‐7594‐5804
2. PET‐Centre, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C (Denmark)
3. Division of Imaging Sciences, King's College London, St Thomas' Hospital, London SE1 7EH (UK)