Abstract by Alexandra Christensen
Physics and Astronomy
Brachytherapy implant evaluation using new isodose surface metrics
Brachytherapy implant placement affects the efficacy of cancer treatment. Implants that allow sufficient dosing of a disease area while avoiding excess are “efficient” and desirable. Several groups have attempted to create metrics to objectively evaluate implant efficiency, but most cannot be optimized because they are too complex or require subjective input. This work creates a metric for implant efficiency to resolve these problems. More efficient implants will result in 3D isodose surfaces (constant dose value contours) that shrink quickly and conform to disease features; to quantify these transitions, the surface area to volume ratio of isodose surfaces and the number of non-contiguous isodose surfaces were calculated as functions of dose level. Simplified targets were simulated with hypothetical catheter arrangements, and isodose surfaces were rendered from these simulations to test the new metrics. Surface area to volume ratio was more informative than surface count. This approach has potential as a simple parameter for measuring implant efficiency and can easily be integrated into an optimization algorithm.