Room: AAPM ePoster Library
Purpose: To introduce and evaluate a novel and efficient workflow for designing 3D-printed patient-specific IC and IC-IS brachytherapy applicators.
Methods: Following a contouring process of a CT-imaged cylinder-applicator, 5 straight source-trajectories intersecting the applicator were recreated in a brachytherapy TPS. The dataset containing DICOM information was then imported into 3D Bolus software (Adaptiiv Medical Technologies) where 3D-image of the applicator was rendered with source-trajectories subtracted into catheter/needle tunnels with user-defined radii. A post-processing cylinder rod was added to the applicator for firmware attachment. The output of the software contained the RT structure of the modified applicator and the corresponding STL file which was used for 3D-printing of the device. Spatial fidelity of the printed applicator was quantified and compared to corresponding RT structure and STL. The printed applicator was then CT-imaged and HU homogeneity was examined. Tolerance levels were established for the spatial fidelity of the printed applicator.
Results: The accuracy of applicator diameter, attachment-rod diameter, inter-tunnel distance and catheter-tunnel diameter was measured in the axial plane on both 3D-printed applicator and STL resulting in ±0.2mm relative to the reference geometry in the TPS and 3D Bolus software. The longitudinal accuracy of the applicator was within twice the input CT slice-thickness and was found dependent on this variable. HU homogeneity of the printed samples was 94±8 HU. Tolerance levels regarding dimensions of the printed applicator were set to 1CT pixel-size in lateral and vertical directions and 2CT slice-thickness in the longitudinal direction. The workflow in the 3D Bolus application took approximately 5 minutes to complete.
Conclusion: This work presents a novel technology and workflow providing a practical approach to efficient and accurate design of personalized IC-brachytherapy applicators. The design and production of the device was accomplished without the need for complex CAD software or any specialized 3D-modelling skills.
Funding Support, Disclosures, and Conflict of Interest: The presenting author of this work is a permanent employee of Adaptiiv Medical Technologies, Inc.