Extended necrosis by using dual-curved therapeutic transducer for noninvasive HIFU surgery

In noninvasive HIFU (High Intensity Focused Ultrasound) surgery, a treatment time can be reduced by using a therapeutic transducer capable of enlarging a coagulated lesion per sonication. Currently, most of studies have been focused on the expansion of necrosis in the lateral direction than the axial direction. In this paper, we present a novel HIFU transducer with a dual curved aperture which can extend DOF (Depth of Focus) resulting in a broad necrotic region in the axial direction. A prototype dual-curved transducer was fabricated and its performance was successfully tested by conducting simulation of bioheat transfer/thermal dose, hydrophone measurement, and in vitro test with a beef liver. Although several design parameters for the transducer were not optimized, the DOF of the proposed method was 3.5 times larger than that of the conventional single element transducer with the same dimension. Thus, the dual-curved therapeutic transducer may be a potential method to reduce treatment time of HIFU surgery.