Room: ePoster Forums
Purpose: 3D metal printing offers the potential to create detailed structures with the increased density necessary to attenuate electrons produced in a linear accelerator. This work investigated the potential of utilizing a high-metal content copper filament, FilaMetâ„¢ (The Virtual Foundry, Stoughton, WI), for 3D printed patient-specific electron cutouts.
Methods: The dosimetric characteristics of a 3D printed copper cutout were measured and compared to a clinical Cerrobend cutout by analyzing percentage-depth-dose (PDD), profile and transmission measurements for 6, 9, 12 and 15MeV electron beams. PDD curves and output factors (at dmax) were acquired with a CC04 ion chamber along the central axis of 3x3cm2 Cerrobend and FilaMetâ„¢ cutouts. The Cerrobend was 14.6mm thick and the copper printed cutout was 8mm thick at the field edge and tapered to 16mm at the frame edge. In-line and cross-line profiles were acquired at a 1cm depth with both cutouts for all energies and compared. Transmission measurements for all energies were acquired at dÂ¬max for varying thicknesses of the copper printed material and compared to the transmission of a clinically used 14.6mm thick piece of Cerrobend.
Results: Output factors were 0.05%, 1.4%, 22.9%, and 37.3% higher using the FilaMetâ„¢ 8mm thick cutout when compared with the Cerrobend cutout for 6, 9, 12, and 15MeV respectively. Transmission measurements for 23.75mm of FilaMetâ„¢ were within 0.11%, 0.15%, 0.03%, and 0.39% higher than 24.25mm of Cerrobend. Profiles qualitatively agreed for 6 MeV electron beams for the FilaMetâ„¢ and Cerrobend cutouts. Discrepancies between the profiles in the penumbra and field width increased with energy.
Conclusion: The 3D printed copper cutout demonstrated comparable performance to standard Cerrobend cutouts at 6MeV, however, due to the limited agreement at higher energies, further investigation with increased copper cutout thickness is necessary for an assessment of the cutout feasibility at higher energies.
Funding Support, Disclosures, and Conflict of Interest: Mike Daniels has a vested interest in and is employed by The Virtual Foundry.