[1] Univ Naples Federico II, Dipartimento Sci Fis, I-80126 Naples, Italy
[2] Univ Naples Federico II, Dipartimento Sci Biomorfol & Funz, I-80126 Naples, Italy
[3] Childrens Hosp Philadelphia, Dept Radiol, Philadelphia, PA 19104 USA
[4] IFAE, Barcelona, Spain
[5] Ist Nazl Fis Nucl, Sez Napoli, I-80125 Naples, Italy
[6] Univ Naples Federico II, Dipartimento Biol Strutturale & Funz, I-80126 Naples, Italy
[7] MIT, Dept Nucl Engn, Cambridge, MA 02139 USA
[8] Univ Naples Federico II, Dipartimento Med Clin & Sperimentale, I-80126 Naples, Italy
[9] Univ Naples Federico II, Dipartimento Biol & Patol Cellulare & Mol, I-80126 Naples, Italy