This study investigates the development of advanced radiation shielding materials incorporating bismuth oxide (Bi₂O₃) nanoparticles (NPs) into polymethyl methacrylate (PMMA) composites, comparing efficacy against I-131 gamma radiation. The NPs exhibit a 1.53-fold reduction in z-average diameter and a significantly higher surface area than Bi₂O₃, ensuring superior dispersion and structural uniformity within the PMMA matrix. These characteristics, validated through SEM, EDX, and XRD analyses, contribute to enhanced gamma radiation attenuation, leveraging the high atomic number and density of Bi₂O₃. Mechanical evaluations reveal that increasing Bi₂O₃-NPs concentrations enhances ductility but reduces tensile strength, likely due to nanoparticle agglomeration and stress concentration. Radiation shielding performance, assessed using XCOM and Phy-X/PSD simulations, demonstrates a direct correlation between Bi₂O₃ content and attenuation efficiency. Notably, composites with 75% Bi₂O₃ content exhibit attenuation properties comparable to, or exceeding, those of PbO₂, achieving superior shielding efficacy at reduced thicknesses across various photon interaction mechanisms. These findings position Bi₂O₃ NPs-enhanced PMMA composites as promising lightweight high-performance alternatives to lead-based shields. By addressing toxicity and environmental concerns associated with lead, this work emphasizes the potential of high-Z nanomaterials in advancing radiation protection applications. This study highlights a transformative approach to designing safer and more efficient shielding solutions, contributing to the next generation of radiation protection materials.

This study employs simulation tools to design and evaluate lightweight, lead-free polymer composites incorporating polytetrafluoroethylene (PTFE), polyethylene (PE), and polyetherimide (PEI) for gamma radiation shielding in nuclear medicine. Targeting clinically relevant photon energies from Tc-99m (140 keV), I-131 (364 keV), and Cs-137 (662 keV), composites’ structural and shielding performance with Bi₂O₃ and WO₃ was assessed using XCOM and Phy-X/PSD. PEI emerged as the most suitable polymer for load-bearing and thermally exposed applications, offering superior mechanical stability and dimensional integrity. Bi₂O₃-WO₃ fillers for Tc-99m achieved a ~7000-fold increase in MAC, I-131 ~2063-fold, and Cs-137 ~1370-fold compared to PbO₂. The PEI-75Bi₂O₃-25WO₃ achieved a ~21-fold reduction in half-value layer (HVL) compared to lead for Tc-99m. For higher-energy isotopes of I-131 and Cs-137, HVL reductions of ~0.44-fold and ~0.08-fold, respectively, were achieved. The results demonstrate that high-Z dual filler polymer composites have an equal or enhanced attenuation properties to lead-based shielding, whilst also enhancing the polymer composites’ mechanical and thermal characteristics. As the use of ionizing radiation increases, so does the potential risks; high-Z dual filler polymer composites provide a sustainable, lightweight, non-toxic alternative to conventional lead shielding.

Tungsten oxide (WO₃) is a high-density material with exceptional radiation attenuation properties, making it a strong candidate for advanced shielding applications. This study explores the structural, mechanical, and shielding performance of WO₃-reinforced polyisoprene composites. Morphological analysis reveals a plate-like structure, indicating robust interfacial interactions that enhance mechanical integrity and thermal stability. X-ray diffraction confirms the crystalline nature of WO₃, while Fourier transform infrared spectroscopy detects distinct W–O bond absorption bands, validating uniform dispersion. Computational analysis using XCOM demonstrates remarkable improvements in attenuation properties, particularly at intermediate- and high-photon energies. While PbO₂ outperforms at lower energies due to the photoelectric effect, Phy-X/PSD analysis confirms that composites with ≥75% WO₃ offer strong shielding capabilities. Variations in effective atomic number, linear attenuation coefficient, and mass attenuation coefficient establish WO₃-reinforced NR as a compelling lead-free alternative, especially for Tc-99m applications. Experimental findings further reveal that increasing WO₃ content significantly reduces Tc-99m gamma radiation dose equivalents Hp(0.07), Hp(3), and Hp(10), emphasizing the potential of WO₃-reinforced composites for next-generation radiation shielding solutions.