assessment of the radiation attenuation properties of several lead free composites by monte carlo simulation

background: in diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range. objective: although lead aprons have good radiation protection properties, in recent years, researchers have been looking for alternative materials to be used instead of lead apron because of some problems derived from lead-content of aprons. because of its lead-content, these radiation protection garments are so heavy and uncomfortable for the staff to wear, particularly in long-time uses. in addition, lead is a toxic element and its disposal is associated with environmental and human-health hazards. method: in this study, several new combinations of lead free materials ((w-si), (w-sn-ba-epvc), (w-sn-cd-epvc)) have been investigated in the energy range of diagnostic radiology in two geometries: narrow and broad beam. geometries of the radiation attenuation characteristics of these materials was assessed in 40, 60, 90 and 120 kvp and the results compared with those of some lead-containing materials ((pb-si), (pb-epvc)). results: lead shields still provide better protection in low energies (below 40 kvp). combination of w-sn-cd-epvc has shown the best radiation attenuation features in 60 and 90 kvp and the composition of (w-sn-ba-epvc) represents the best attenuation in 120 kvp, even better than previously mentioned lead- containing composites. conclusion: lead free shields are completely effective for protection against x-ray energies in the range of 60 to 120 kvp.