1. Unit of Medical Physics; Azienda Ospedaliero-Universitaria Pisana; Pisa Italy
2. Radiodiagnostic Section, Department of Clinical Physiopathology; University of Florence; Firenze Italy
3. Biomedical Engineering Laboratory, Department of Electronics and Telecommunications; University of Florence; Firenze Italy
4. Unit of Radiology; Versilia Hospital; Lido di Camaiore (LU) Italy