A Novel Design for Production of Efficient Flexible Lead-Free Shields against X-ray Photons in Diagnostic Energy Range

Lead-based radiation shields are widely used in radiology departments to protect both workers and patients from any unnecessary exposure to ionizing radiation. Recently there has been a great deal of concern expressed about the toxicity of lead. Human lead toxicity is well documented. In that light, production of environmentally-friendly lead-free radiation shields with less weight compared to conventional lead-based shields is a challenging issue. The aim of this study was to design lead free flexible radiation shields for protection against X and gamma rays. In this investigation, a wide variety of metallic compounds which potentially could be appropriate radiation shields, were studied. The Monte Carlo code, MCNP4C, was used to model the attenuation of X-ray photons in shields with different designs. Besides simulation, experimental measurements were carried out to assess the attenuation properties of each shielding design. On the other hand, major mechanical properties of this shield such as tensile strength, modulus and elongation at break were investigated. Among different metals, tungsten and tin were the two most appropriate candidates for making radiation shields in diagnostic photon energy range. A combination of tungsten (45%) and tin (55%) provided the best protection in both simulation and experiments. In the next stage, attempts were made to produce appropriate Tungsten-tin-filled polymers which could be used for production of shielding garments. The density of this tungsten-tin-filled polymer was 4.4 g/cm3. The MCNP simulation and experimental measurements for HVL values of this shield at 100 kVp were 0.26 and 0.24 mm, respectively. On the other hand, this novel shield provides considerable mechanical properties and is highly resistant to chemicals. The cost-effective lead-free flexible radiation shield produced in this study offers effective radiation protection in a diagnostic energy range. This environmentally-friendly shield may replace the traditional lead-based shielding garments.