1. Turku PET Centre, University of Turku, Turku, Finland
2. Department of Medicine, University of Turku, Turku, Finland
3. Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland
4. GlaxoSmithKline, Greenford, U.K
5. Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy