Evaluation of 3D printed shielding for radiotherapy patients with skin cancer

Abstract

Lead (Pb) shielding presents considerable health and environmental risks, prompting the need to investigate alternative materials. This study evaluates the effectiveness of W-PLA and Cu-PLA as 3D printed composite shielding materials upon the standard shielding for skin cancer radiotherapy. Five beam qualities (80-150 kVp) were used in this study, which were generated by an XSTRAHL 150 x-ray unit. The investigation involved various dosimetric measurements for all three shielding materials, including half-value layer (HVL) and relative output factors (ROF) measured by an Advanced Markus ionization chamber and Gafchromic EBT3 radiochromic film. This included determining the required thickness of each material to achieve 5% transmission as required for shielding to the patient to minimize the dose to healthy tissue. HVL and W-PLA transmission measurements were verified through Monte Carlo calculations using SpekPy to generate beam spectra. While the results indicate that both 3D printed materials require larger thicknesses for 5% transmission, only 1 mm thickness of W-PLA provided ≤ 4% transmission across all beam energies tested. In contrast, up to 16 mm of Cu-PLA is required, demonstrating its suitability for lower beam energies only. This study supports the integration of custom 3D printed materials into radiotherapy shielding, eliminating exposure to Pb toxicity.