High-intensity focused ultrasound (HIFU) causes selective tissue necrosis through heating and is used for a noninvasive treatment of cancer therapy. However, HIFU thermal treatment has a problem of long treatment time because cooling time is needed between two consecutive shots of focused ultrasound exposure to avoid near-field heating owing to heat accumulation. It is known that acoustic cavitation generated in the focal region of HIFU enhances tissue heating. The objective of this study is to develop a method to accelerate HIFU thermal treatment by using cavitation bubbles. Cavitation bubbles were generated at six positions in the direction perpendicular to ultrasound propagation and they were observed by high-speed ultrasound imaging in real time. The coagulation volumes of chicken breast with and without cavitation bubbles were compared. The results show the high efficiency of the proposed HIFU exposure sequence using cavitation-enhanced heating for HIFU thermal treatment.
