Fully customizable bronze-PLA lung shields using 3D printing for total body irradiation (TBI)

Purpose. Total body irradiation (TBI) is a critical component in the treatment of hematological malignancies, but it carries a risk of radiation-induced lung damage. Traditional lung shields, typically made of lead or Cerrobend, are used to protect lung tissue during TBI. However, these shields require manual fabrication, present toxicity concerns, and are difficult to reproduce in the precise geometry needed for each individual patient. This study investigates the feasibility of 3D-printed bronze-polylactic acid (PLA) lung shields as a non-toxic, customizable alternative to conventional shields in TBI procedures.Materials and Methods. Bronze-PLA lung shields were 3D-printed using a PLA filament with 60% bronze powder by weight. Two thicknesses of 1.8 cm and 3.3 cm were tested. Radiation transmission was measured using a Varian TrueBeam linear accelerator (6 MV and 15 MV photon beams) at isocenter (90 cm source-to-axis distance, SAD) and extended field setup (430 cm source-to-surface distance, SSD). Measurements were repeated with a conventional wax-lead shield for comparison.Results. At 100 cm SAD and 6 MV, the 1.8 cm bronze-PLA shield transmitted 92.12% (standard error, SE = 0.03%), while the thicker (3.3 cm) bronze-PLA shield reduced transmission to 77.08% (SE = 0.02%). Under similar conditions, the wax-lead shield transmitted 86.43% (SE = 0.13%). For 15 MV beams, both the wax-lead and bronze-PLA shields exhibited higher transmission, with the 3.3 cm bronze-PLA shield providing improved attenuation relative to the thinner shield. At the extended SAD, the thinner bronze-PLA shield transmitted more than the wax-lead block, but increasing thickness consistently improved attenuation.Conclusion. The 3D-printed bronze-PLA lung shields demonstrate promising potential in TBI procedures, offering advantages in customization, reduced toxicity, and improved workflow efficiency. While differences in transmission characteristics were observed, particularly at higher energies and extended SDD, these findings provide a foundation for further optimization of 3D-printed shielding for TBI protocols.