Room: Room 209
Purpose: To develop and validate 3D printed brachytherapy applicators and protocols designed for skin cancers, and keloid treatments. This novel technique has great potential to enhance treatment outcomes, function preservation, and cosmesis.
Methods: We constructed 3D printed personalized applicators by extracting a patientâ€™s skin surface from processed diagnostic CT images and transferring the patient anatomy to CAD software to design the applicator and catheter path. Our technique assures the construction of an indexed applicator with one-to-one contact matching to the patientâ€™s skin in the region of the treated malignancy. Our technique facilitates treatment computation and millimetric accuracy of applicator placement, consequently treating skin malignancies with reproducible and accurate dose distributions with respect to the prescribed dose. Materials were tested for autoclave and patient comfort. Film dosimetry and a Rando phantom were used to validate dose distributions against a clinical treatment planning system (TPS).
Results: Studies were performed on multiple applicators of different complexity from simple geometries equivalent to a commercial H.A.M. applicator to complex conformal applicators to treat ear and nose malignancies. No degradation in their physical properties occurred within 20 autoclave cycles. Dosimetric studies in end-to-end evaluations reveal better than 95% agreement for a gamma test with 3% dose equivalence and 1 mm distance-to-agreement criteria. The isodose lines show high conformality to the PTV and absolute dosimetry agrees with the results of the TPS and second check verification in the anthropomorphic phantom for all the studied cases.
Conclusion: We demonstrated the feasibility of using 3D printed applicators and flexible materials to treat skin malignancies. We identified printing parameters for a family of printable materials to construct personalized brachytherapy applicators with submillimeter precision. 3D printing is a clinically viable novel technique and can mimic current commercial applicators as well as generate personalized flexible applicators.