1. Radiation Oncology department. National Cancer Institute, Cairo University & Children’s Cancer Hospital, Cairo, Egypt
2. Division of Radiobiology, Radiation Medicine, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa
3. Department of Radiology, Faculty of Medicine, Egypt and Department of Diagnostic Imaging, Cairo University, St. Jude Children’s Research Hospital, Memphis, TN, USA
4. Radiation Oncology Department, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa