[1] Univ Athens, Dept Med Phys, Sch Med, Athens, Greece
[2] Karolinska Inst, Stockholm, Sweden
[3] Stockholm Univ, Med Radiat Phys, Stockholm, Sweden
[4] Univ Aveiro, Phys I3N, Aveiro, Portugal
[5] Univ Texas Hlth Sci Ctr San Antonio, Dept Radiat Oncol, San Antonio, TX 78229 USA
[6] Areteion Univ Hosp, Dept Radiol, Athens, Greece
[7] Hygeia Hosp, Dept Radiosurg & Med Phys, Athens, Greece
[8] Hygeia Hosp, Dept Radiotherapy & Med Phys, Athens, Greece