Program Information
3D Printing of Surface Applicators for HDR Brachytherapy
S Clarke1*, J Robar2 , M Yewondwossen2 , (1) 3D Bolus Inc., Halifax, NS, (2) Nova Scotia Health Authority, Halifax, NS
Presentations
WE-AB-605-1 (Wednesday, August 2, 2017) 7:30 AM - 9:30 AM Room: 605
Purpose: Skin cancer is one of the most common forms of cancers and has been proven to be effectively treated with HDR brachytherapy. However, customized surface HDR surface applicator fabrication is a time consuming and challenging process, especially for irregular surfaces. The aim of this study is to report on the performance of an in-house methodology facilitating creation of catheter tunnels through a 3D printed surface applicator in an automated fashion.
Methods: HDR surface applicators with the desired shape, thickness and extent were defined in the treatment planning system based on the patient’s pre-treatment CT image data. Following export of this structure in DICOM RT format, in-house algorithms defined in Python were employed to define equispaced trajectories of catheter tunnels ensuring a uniform distance from the skin surface. For this study, catheters tunnels were 10 mm apart and 5 mm from the skin surface. The structure was then converted to the STL format for 3D printing. All HDR surface applicators in this work were 3D printed using a Taz5 3D printer (Lulzbot) using the Ninjaflex filament (NinjaTek, Pennsylvania, USA). The method was evaluated for applicators designed for treatment at the sites of nose, humerus and calf.
Results: The created tunnels followed the patient anatomy and able to successfully fit brachytherapy catheters. The distance from the patient surface and between catheters tunnels were also kept at the desired distance except in regions with abrupt anatomical changes. Use of a 3D printed bolus reduced air gap volume between skin and applicator by more than 50% than Freiburg Flap.
Conclusion: 3D-printed HDR custom surface mould applicators for HDR brachytherapy treatment of superficial lesions fit better to highly irregular surfaces than Freiburg Flap and achieve a better dose conformity.
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