1 Department of Physics, School of Natural Sciences and Munich School of BioEngineering, Technical University of Munich, Garching, Germany.
2 Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Neuherberg, Germany.
3 Karlsruhe Institute of Technology, Institute of Microstructure Technology, Eggenstein-Leopoldshafen, Germany.
4 Philips Research, Hamburg, Germany.
5 Philips Medical Systems DMC GmbH, Hamburg, Germany.
6 Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, München, Germany.