1 Department of Radiation Oncology, Iridium Netwerk, Wilrijk-Antwerpen, Belgium; Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk-Antwerpen, Belgium. Electronic address: Philip.poortmans@telenet.be.
2 Breast Radiation Therapy Unit, Sheba Tel Hashomer, Ramat Gan, Israel; Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
3 Department of Experimental and Clinical Biomedical Sciences "M. Serio," University of Florence, Florence, Italy; Radiation Oncology Unit, Oncology Department, Azienda Ospedaliero Universitaria Careggi, Florence, Italy.