1. Radiation Oncology Unit, 1st Department of Radiology, Aretaieion University Hospital, Medical School, National and Kapodistrian University of Athens (NKUOA), Athens, Greece
2. Radiation Oncology Department, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
3. Radiation Oncology Department, Metropolitan Hospital, Piraeus, Greece
4. Medical Physics Department, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
5. Radiation Oncology Unit, 2nd Department of Radiology, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens (NKUOA), Athens, Greece.