Lead-free transparent nanocomposite for efficient clinical X-ray shielding

The increasing use of X-ray imaging in the medical field has generated a growing need for efficient shielding materials to protect healthcare personnel, especially those interventional surgeons, from radiation exposure risks. Conventional lead-based materials suffer from a high bio-toxicity and low transparency, which hinders their application in interventional surgeries. Herein, we report a lead-free nanocomposite of LaF₃ particles and poly(vinyl alcohol). Due to the low refractive-index contrast, the monolayer composite exhibits a high optical transparency of up to 86% in the visible light region with a fluoride-ceramic content of up to ∼70 wt%. Importantly, the transparency of the composite remains at 81% after stacking up 23 monolayers in a layer-by-layer manner. Due to the characteristic K-edge absorption of lanthanide element, the heavy-loading nanocomposite has showcased an effective X-ray attenuation ability (μ = 46.1 cm⁻¹ @ 50 kV) in the clinical range, which is 2.3 times that of the reported Pb-based glass. The shielding performance is further tested in a real clinical scenario, showing a 66% blocking efficacy for an 80-keV X-ray source. Our work provides an efficient approach for developing the next generation of biocompatible and transparent radiation shielding materials, which could benefit personal protection in fields involving interventional surgery, space-suit design, and the nuclear industry.