Author: Michael Kudla, Stephanie Merkl 👨🔬
Affiliation: BC Cancer - Kelowna 🌍
Purpose: 3D modeling for 3D printed GYN high dose rate (HDR) brachytherapy templates can be a time-consuming, error-prone process. To simplify the creation these templates, a software application has been created which can import dicom plans and generate a 3D printable cylinder with channels to facilitate preplanned needle trajectories. This study validates brachify for a range of use cases for vaginal and cervical brachytherapy, with and without a tandem.
Methods: HDR brachytherapy treatment pre-plans for 21 previously treated patients were exported as dicom files from our clinical treatment planning systems (Brachyvision and Oncentra). 10 patients were planned with a tandem.
Each plan was imported into brachify. Cylinders were modified according to the planned diameter, length, needle channel diameter, tandem channel diameter, and custom tandem geometry cutouts were generated.
Each cylinder STL was generated and evaluated for printability and channel geometry correctness in a commercial slicing software (PreForm, Formlabs). In addition, an operating room reference sheet was generated (using brachify) for each plan showing the channel mapping for each cylinder, and interstitial needle depths. These were manually verified for correctness.
Results: Each cylinder STL was visually passed for printability and needle trajectory accuracy. Reference sheets were verified as correct by comparison with TPS values. Applicator (needle or tandem) name and channel number were validated and planned interstitial needle lengths matched those listed in the operating room reference sheet. The base map generated for each OR reference sheet was cross validated with the TPS model.
Conclusion: Brachify has been shown to be an effective solution for the creation of 3D printable interstitial cylinder templates for HDR vaginal and cervical brachytherapy, with or without a tandem. This software simplifies the generation of 3D printable template models once a treatment pre-plan has been created. Brachify is available for download as an executable at github.com/brachify-release.