C. Geng, C. Gong, D. Chen, D. Shu, H. Yu, S. Hang, X. Tang,

mahbobeh nazarnejad science and research branch, islamic azad university, tehran, iran

somayeh nourollahi m.sc.in medical physics, faculty of medicine, tehran university of medical sciences, tehran, iran mahmoud allahverdi associate professor, medical physics dept., faculty of medicine, tehran university of medical sciences, tehran, iran mahbod esfahani m.sc.in medical physics, radiotherapy dept., cancer institute, tehran university of medical sciences, tehran, iran mehdi aghili assistant professor, radiotherapy dept., cancer institute, tehran university of medical sciences, tehran, iran vahid changizi assistant professor, radiology technology dept., faculty of allied medical sciences, tehran university of medical sciences, tehran, iran

ahad ollah ezzati faculty of physics, university of tabriz, tabriz, iran seyed rabi mahdavi department of medical physics, iran university of medical sciences, tehran, iran

sedigheh sina ph.d. student, nuclear engineering, medical radiation trends, faculty of mechanical engineering, shiraz university, shiraz, iran. reza faghihi assistant professor of medical radiation, faculty of mechanical engineering, radiation research center, shiraz university, shiraz, iran. mehdi zehtabian ph.d. student, nuclear engineering, medical radiation trends, faculty of mechanical engineering, shiraz university, shiraz, iran. simin mehdizadeh m.sc. of nuclear engineering, medical radiation trends, radiation research center, shiraz university, shiraz, iran.