1. Department of Radiology & Nuclear Medicine; VU University Medical Center; De Boelelaan 1117, 1081 HV Amsterdam The Netherlands
2. Faculty of Medical Sciences; Nuclear Medicine and Molecular Imaging; Hanzeplein 1, 9713 GZ Groningen The Netherlands
3. PET Center; Johns Hopkins Hospital; Nelson B1125, 1800 Orleans Street Baltimore MD 21287 USA