Feasibility of HIFU tissue ablation in the presence of ribs using a 2D random phased array

The goal of the work was to demonstrate feasibility of HIFU tissue ablation through the rib cage using a high power 2D random phased array. A method to minimize heating ribs while maintaining high intensities at the focus of the array was proposed and tested theoretically and experimentally. A 2D 1‐MHz phased array with 254 randomly distributed elements and a phantom of porcine rib cage were used in experiments. Intensity distributions were measured in the plane of the rib phantom and in the focal plane of the array using an infra‐red camera. Theoretical and experimental results show that if the position and the shape of ribs are known it is possible to provide adequate focusing through the ribs without overheating them for a single focus, including steering at ±10–15 mm off and ±20 mm along the array axis. The results suggest that the method is potentially useful for clinical applications of HIFU for which the rib cage lies between the transducer and the targeted tissue.