Coagulation of Large Regions by Creating Multiple Cavitation Clouds for High Intensity Focused Ultrasound Treatment

High-Intensity focused ultrasound (HIFU) is attracting attention as a minimally invasive therapeutic modality. However, it has a problem of a long treatment time. To improve its treatment throughput, we developed a method of coagulating a large region at one time utilizing multiple clouds of cavitation. It is known that acoustic cavitation generated in the focal region of HIFU enhances tissue heating. In the experiment in this study, the focal distance was changed using an annular array transducer. Cavitation clouds were generated at three positions within a fraction of a second by high-intensity ultrasound pulses. The tissues in the vicinity of the cavitation clouds were coagulated simultaneously with non-spherically focused ultrasound waves at a relatively low intensity. The result suggests that the HIFU treatment time is significantly shortened by employing the proposed method.