Room: Davidson Ballroom A
Purpose: High-dose-rate skin brachytherapy (HDR-SB) for malignant skin diseases provides conformal therapy for many indications. For complex cases skin brachytherapy requires the fabrication of a thermoplastic mask with flexible multi-channel surface applicators attached, a planning CT and plan optimization with manual channel digitization and semi-automated planning. To expand availability of HDR-SB and to simplify the process a fully automated approach is presented.
Methods: A planning system that features 3D printing, scanning as well as augmented-reality (AR) was developed and the following workflow is proposed: (1) 3D optical-scanning of the skin surface with a mobile device. (2) Automated generation of a conformal 3D printable applicator holder including treatment plan. (3) Planning CT that ensures the correct fit of the applicator and connected dosimetry followed by treatment. For fractionated regimens, the daily alignment of the mask is confirmed by AR (4). The proposed methodology is tested on a phantom with a hypothetical head-and-neck lesion.
Results: The 3D scan was obtained in less than a minute. The RMSE of the scan compared to the ground truth (CT) was found to be 1.2mm. Generation of the printable mask model and connected catheter optimization, including dwell-times, took 10.2min. Printing time was 9.5h. Attaching the applicator to the mask took 15min. The repeatability for the AR was found to be (0.13Â±0.34)mm. The achieved quality was comparable to manual planning with the clinical planning system.
Conclusion: The proposed method allows fully automated treatment planning for HDR-SB without time intensive manual fabrication and interactions. The resolution of the mobile device scanner is sufficient to generate 3D printable masks even for complex topologies. The proposed system significantly reduces the complexity applicator creation, removes manual catheter digitization and the associated potential for error, and reduces clinical time. It could potentially save the patient at least one visit to the center.
Not Applicable / None Entered.