1 Medical Imaging Centre, Department of Nuclear Medicine and Molecular Imaging (EB50), University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. r.h.j.a.slart@umcg.nl.
2 Biomedical Photonic Imaging Group, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands. r.h.j.a.slart@umcg.nl.
3 Biomedical Photonic Imaging Group, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands.
4 Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, Leiden, The Netherlands.