Accelerated Thermal Ablation of Biological Tissue Volumes using HIFU beams with Shock Fronts

The paper presents the results of a numerical experiment comparing the rates of volumetric thermal ablation of bovine liver tissue ex vivo, generated by a multielement ultrasound array Sonalleve V1 3.0T (Philips Healthcare) using various exposure protocols. Pulsed sonications with the same time-average, but different peak power and duty cycle were modeled. The treatment trajectory consisted of a discrete set of single foci located at the center and along two concentric circles. Beam focusing in tissue was modeled using the Westervelt equation, the temperature field was calculated using the bioheat equation, and the threshold of tissue damage was determined according to the thermal dose formulation. It is shown that pulsed shock-wave exposures can provide up to three times faster volumetric ablation of tissue as compared to continuous quasi-harmonic wave treatments.