Innovative nano-shielding for minimizing stray radiation dose in external radiation therapy: A promising approach to enhance patient safety

This study investigates the effectiveness of novel nanocomposite shielding materials in reducing out-of-field radiation doses during radiation therapy, employing Geant4 Monte Carlo (MC) simulations alongside an anthropomorphic female phantom. The research focuses on two radiation modalities: 6 MV beams with and without flattening filters. Utilizing the Geant4 MC code, detailed simulations of a Varian Clinac 2100C/D linear accelerator and an ICRP-145 mesh-type human phantom were conducted to estimate the doses to out-of-field organs from unintended secondary radiation. This involved simulating a comprehensive linac model, including all relevant beam-line components, and assessing the shielding effects of three different nanocomposites doped with metal nanoparticles at various thicknesses. The nanocomposites, comprising Polytetrafluoroethylene (PTFE), with PtO₂, IrO₂, and Bi₂O₃ nanoparticles, were evaluated for their potential to reduce patient organ doses from stray photon doses. The results showed that these materials could significantly lower radiation exposure to non-target tissues.