Non-invasive ultrasound surgery: Role of microbubble enhanced cavitation

A method to make in-vivo acoustic cavitation practical as a mechanism for non-invasive ultrasound surgery is presented. Unlike thermal ablation mechanisms, acoustic cavitation can destroy tissue without heating complex overlying layers. However, cavitation thresholds are widely varying in tissues and cavitation requires high intensities to initiate. We have shown that introducing microbubbles (Optison/sup TM/ ultrasound contrast agent) significantly reduces the threshold for cavitation in canine kidneys. Non-invasive ultrasound surgery of deep-seated tissues may be possible using this approach.