Simulations of percutaneous RF ablation systems

Abstract

Breast and liver cancers provide an ongoing challenge in regard to treatment efficacy and successful clinical outcomes. A variety of percutaneous technology has been applied for thermal treatment of the liver and breast, including laser, microwave, cryogenic and radiofrequency (RF) devices. When simplicity and cost are factored in, RF hardware and applicators offer the most cost-effective treatment pathway by interventional radiologists and surgeons. To model percutaneous RF treatments in liver and breast, simulations were done in 3D with a finite element model. Three RF systems were modeled, including 1) single needle; 2) clustered needle, cooled and uncooled; and 3) deployable, hook electrodes. The results show the limitations of the systems in percutaneous procedures, depending on temperature limits, duration of treatment, and whether the devices are cooled or uncooled. For thermal treatment, the isotherm of 55°C was considered the margin of coagulation necrosis. The 3-D volumes of 55°C and 65°C isotherm shells aid in the selection of the best method to improve clinical outcomes, while paying attention to the size and shape of the applicator and duration of treatment.