Room: AAPM ePoster Library
Purpose: This work aimed to develop a cost-effective procedure for keeping catheters uniformly separated from each other, in the construction of a patient-specific custom mold to be used in Ir-192 HDR treatment of superficial lesions on a curved surface.
Methods: A patient-specific mold was created for a head and neck phantom with catheters placed on an Aquaplast RTTM Custom BolusTM. Strips of Aquaplast RTTM were used to robustly secure the catheters to the underlying bolus. The strips of Aquaplast RTTM were attached to the underlying bolus before either material cooled and hardened (<5 min). To efficiently position the catheters in this time frame, reusable, in-house foam blocks of 2 x 2 x 10 cm3 were designed with 5 mm grooves on one face of the blocks. The grooves were parallel and 1 cm from each other. The foam was used to hold the catheters at equal spacing on the curved surface of the neck during construction of the mold. A CT-based treatment plan was created with the Oncentra® Brachy treatment planning system.
Results: The manufactured foam blocks maintained a consistent separation of the catheters from each other on the curved surface of the neck. This was seen in the reconstructed catheters in the CT image. Separation distances ranging from 0.5 cm to 1.5 cm were measured on sections of the surface with more curvature, and separation distances with an average of 1 cm were measured on flat sections of the surface. A reasonable plan was achieved for an irregularly defined planning target volume around the neck.
Conclusion: Foam blocks were manufactured to keep catheters parallel to each other in the time-sensitive construction of a mold for the treatment of a superficial lesion on a curved surface. These inexpensive and reusable foam blocks helped to create a uniform catheter distribution.
Not Applicable / None Entered.