[1] Oncol Inst So Switzerland, Bellinzona, Switzerland
[2] Gavle Cent Hosp, Radiooncol Dept, S-80187 Gavle, Sweden
[3] Ist Ospitalieri Cremona, Radiooncol Dept, Cremona, Italy
[4] Univ Hosp Geneva, Dept Radiat Oncol, Geneva, Switzerland
[5] IRCSS, Radiooncol Dept, Ist Clin Humanitas, Milan, Rozzano, Italy