[1] Veneto Inst Oncol IOV IRCCS, Radiotherapy Unit, Padua, Italy
[2] Veneto Inst Oncol IOV IRCCS, Med Phys Dept, Padua, Italy
[3] Veneto Inst Oncol IOV IRCCS, Med Oncol Unit 2, Padua, Italy
[4] Univ Padua, Sect Otorhinolaryngol Head & Neck Surg, Azienda Osped Padova, Padua, Italy
[5] Abano Terme Hosp, Dept Radiat Oncol, Padua, Italy
[6] Harvard Med Sch, A A Martinos Ctr, Massachusetts Gen Hosp, Charlestown, MA 02115 USA