Marco Ferrari1, Joseph P Culver2, Yoko Hoshi3, Heidrun Wabnitz4. 1. University of L'Aquila, Department of Life, Health and Environmental Sciences, Via Vetoio, 67100, L'Aquila, Italy. 2. Washington University School of Medicine, Department of Radiology, 4525 Scott Avenue, Campus Box 8225, St. Louis, Missouri 63110, United States. 3. Hamamatsu University School of Medicine, Institute for Medical Photonics Research, Department of Biomedical Optics, 1-20-1 Handayama, Higashi-ku, HamamatsuShizuoka 431-3192, Japan. 4. Physikalisch-Technische Bundesanstalt (PTB), Department of Biomedical Optics Abbestr. 2-12, 10587 Berlin, Germany.