1. Department of Radiological Sciences, King Saud University, PO Box 10219, Riyadh, 11433, Saudi Arabia
2. Physics Department, Faculty of Science and Humanities, Salman Bin AbdulAziz University, Al-kharj, Saudi Arabia
3. National Inst. of Standards (NIS), Ionizing Radiation Metrology Laboratory, Tersa St., PO Box 136, Giza, 12211, Egypt
4. Medical Physics Department, Faculty of Medicine, Jazan University, Jazan, Saudi Arabia