Program Information
Generation of 3D Printed Surface Applicator Surrogates From the Brachyvision Solid Applicator Library for Patient Simulation
D Barbee*, I Das , T Duckworth , NYU Langone Medical Center, New York, NY
Presentations
SU-I-GPD-T-51 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: Shielded brachytherapy applicators pose challenges to CT-based brachytherapy planning due to CT artifacts caused by high atomic number (Z) materials, thus affecting dose calculation accuracy. As a result, applicator placement typically relies on imperfect wire placement to identify the intended applicator placement during planning. This work uses 3D printed plastic surrogates to simulate applicator treatment position for CT-based brachytherapy planning, thus avoiding calculation errors due to high Z artifacts.
Methods: Brachyvision 13.7 applicator models GM11004590-##.acrpx (Surface) and GM11010080-##.acrpx (Leipzig) were imported as XML files into a custom .Net application. Models for “inset” and “shield” parts of the XML files were created by exporting vertices and triangles of each model into Stanford (PLY) format. Models were imported into Meshmixer to repair meshes, followed by export to MakerBot software where meshes were oriented on the build plate, 3D printing settings were set, and print binary files (x3g) exported. All objects were printed using: 0.3 mm slices, 3 shells, 75% infill, rafts, no supports; however, the 45 mm Leipzig cone used supports and both 45 mm and applicator used 0.2 mm slices.
Results: Each piece (“inset” and “shield”) was individually printed on a MakerBot Replicator 2 using PLA filament. Shields and applicator printed in 26-37 minutes and 75 minutes, respectively. The 3D printed models were CT simulated on a CIRS phantom and were imported into Brachyvision where Brachyvision library models were perfectly overlaid on the planning imaging set.
Conclusion: Plastic models of shielded brachytherapy surface applicators were successfully generated from the Brachyvision model library. The 3D printed models are cheap, disposable, and can be quickly remade rather than re-sterilized for each patient. Plastic surrogates will allow for physicians to determine applicator cone size directly on the patient prior to CT without introducing high Z imaging artifacts into dose calculation.
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