Exhibit Hall | Forum 7
Purpose: Predetermined, patient-specific needle templates simplify needle insertion while concurrently giving more flexibility to deposit dose beyond the reach of conventional brachytherapy applicators. This work addresses the development of a custom/patient specific applicator template library for interstitial HDR brachytherapy.
Methods: Several design features were considered while developing applicator library for the UT Southwestern HDR brachytherapy program: a) applicator integrity, b) biocompatibility, and c) sterilization. The custom needle templates were designed in Inventor (AutoDesk,Inc.) and fabricated with a stereolithography(SLA) 3D-printer (Form3B,FormLabs,Inc.) using a FormLabs BioMed-clear resin to achieve the high quality and smooth finished surface. The BioMed-clear resin is an acrylic-based and certified United States Pharmacopeia-Class-VI bio-compatible plastic material for breached or compromised surfaces. Design integrity was evaluated after cleaning and disinfecting followed by repeated autoclave sterilizations (121°C gravity cycle for 30 minutes). The current custom library includes 3 interstitial treatment applicators, a) multichannel interstitial cylinder, b) patient specific interstitial template, and c) rotational interstitial ovoid.
Results: These applicators were designed to guide needle insertion to different locations of the tumor where the regular tandem/ovoid or cylinder cannot effectively deposit dose. Custom/patient specific applicators could be fabricated before the first fraction with the desired needle insertion locations pre-defined on simulation images. Multichannel interstitial cylinder could deposit asymmetric dose off cylinder central axis while 6 needle guides laying around the cylinder surface. The patient specific interstitial template could pre-arrange the needle pattern and template size according to patient treatment needs. The rotational interstitial ovoid has three sets of needle guides perpendicular to the ovoid at three different heights in anterior/posterior direction. The middle needle guides could rotate along ovoid axis for different insertion angles.
Conclusion: Custom 3D-printed needle templates effectively assist physicians to place the needles close to the predetermined locations. The brachytherapy limitation could be pushed beyond the regular applicators.
Not Applicable / None Entered.