Application of Lead Substitute Shielding Materials for X and Gamma-Rays Attenuation in Diagnostic Radiology: A Review Article

Lead is the most widely used material for radiation protection in diagnostic radiology because its ability to attenuate x-rays is superior to other materials due to its high atomic number, high density, and its higher economic affordability. However, lead shields have serious disadvantages, such as high toxicity, heavy weight, poor flexibility, and low chemical stability. These disadvantages have oriented extensive research toward the use of non-lead composite shields. This study aims to review the materials and compounds proposed as alternatives to lead in x-ray shields and investigate their effectiveness in removing the limitations of standard lead shields. In total, 83 articles were reviewed using databases such as Google Scholar, Medline, Web of Science, Scopus, and Embase with the keywords of radiation protection, lead-free shields, and dianostic radiology. Since a wide range of materials can be used as radiation shields, the results show that in addition to the atomic number, the size of the particles can also be effective in increasing the radiation attenuation efficiency to the extent that the nano-sized non-lead shields have been more effective in radiation protection. Also, compared to common single and combined materials, multilayer polymer composites have better photon attenuation capability and reduce the possibility of x-ray penetration more effectively. Research to find appropriate alternative materials for lead and the optimization of the efficacy of radiation shields, should be continued, as it is difficult to achieve a light, flexible, low cost shield with a high x-ray attenuation in the entire range of diagnostic photon energies.