Ultra Cheap 3D-Printed Electron Cutout for Elekta Linear Accelerators
Abstract
Purpose
To develop and characterize a lost-cost, 3D-printed, patient-specific electron cutout filled with steel ball bearings (BBs) for use with Elekta linear accelerators, and to assess current electron radiotherapy (ERT) practices and clinical perspectives on existing and emerging electron cutout technologies in California.
Methods
A 10x10 cm2 electron cutout was developed using a 3D-printed shell filled with los-cost steel BBs and a reusable copper support bracket. A 7 cm circular aperture was fabricated and tested against an equivalent CNC-copper cutout. TG and LR profiles were measured at dmax for 6-15 MeV electrons at 100 cm SSD on an Elekta Infinity, using a PTW1500 array. Aperture size at isocenter was confirmed with EBT3 film, and transmission of solid cutouts at 2 cm water-equivalent depth was compared with CNC-copper and Cerrobend. A clinical survey on ERT practices and perceptions of 3D-printed cutouts was distributed to California AAPM members.
Results
Dose profiles from the 3D-printed cutout were comparable to CNC-copper, with 80-20% penumbra widths <1 mm for 6 and 9 MeV beams and <2 mm for 12 and 15 MeV beams. Full width at half maximum and transmission were also comparable, and the 7 cm circle aperture was confirmed at 100 cm SSD. 24 AAPM members responded to the survey; all offered ERT, typically comprising 1-5% of treatments. Cutouts were primarily Cerrobend (58.3%) or CNC-copper (33.3%). Cerrobend users cited toxicity concerns, while CNC-copper users cited long fabrication times. Awareness of 3D-printed solutions was high, with reduced fabrication time and elimination of toxic materials as key benefits, though workflow integration remained a concern.
Conclusion
A steel BB-filled, 3D-printed electron cutout demonstrates comparable dosimetric performance to CNC-copper cutouts while addressing key clinical limitations of existing technologies. This approach shows promise as a safe, cost-effective, and clinically viable alternative for ERT.