1. Institute of Physics of Biological Systems; Ecole Polytechnique Fédérale de Lausanne; CH-1015 Lausanne Switzerland
2. Laboratory for Functional and Metabolic Imaging; Ecole Polytechnique Fédérale de Lausanne; CH-1015 Lausanne Switzerland
3. Department of Radiology; Université de Lausanne; CH-1015 Lausanne Switzerland
4. School of Chemistry; Tel-Aviv University; Ramat-Aviv Tel Aviv Israel
5. Center of Biomedical Imaging (CIBM); Lausanne Switzerland
6. Department of Radiology, Geneva University Hospital and Faculty of Medicine; University of Geneva; CH-1211 Genève 4 Switzerland