1. Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran
2. Associate Federation Scheme, Medical Physics Field, International Centre for Theoretical Physics (ICTP), Trieste, Italy
3. Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
4. Departement of Medical Physics, Reza Radiation Oncology Center, Mashhad, Iran