1IRCCS SDN, Naples, Italy, 2Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy, 3Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy, 4Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 5Institute of Biostructure and Bioimaging, National Research Council, Naples, Italy