ZnO–Bi2O3 Composites for Enhanced Shielding Performance in Radiation-Protective Skin Modeling Packs

Radiation shielding in medical settings has traditionally relied on fixed structural models, with thicknesses and material composition determined by their shielding effect against direct X-rays. However, clinical practice increasingly demands lightweight and biocompatible shielding tools that can be locally applied to specific anatomical regions. Such tools should allow rapid installation and removal, skin protection, and disposable as well as continuous shielding. As a potential solution, this study aimed to improve the effectiveness of a cream-type material that directly coats the skin with shielding agents. A modeling pack was fabricated using bismuth oxide, an eco-friendly shielding material; zinc oxide, commonly utilized in cosmetics for ultraviolet protection; and alginate, which enhances skin adhesion by evaporating moisture. The effects of varying bismuth oxide and zinc oxide ratios on porosity and shielding performance were evaluated to establish assessment criteria for future commercialization. The experimental results demonstrated that higher proportions of bismuth oxide enhanced the shielding effect, while a linear change in shielding rate was observed at a thickness of 1.0 mm. Although pore structure variations were minimal, optimizing inter-particle arrangement may further improve skin adhesion. These findings suggest that cream-type radiation-shielding materials are highly promising for medical applications.