Correlation between acoustic backscatter variability and tissue damage produced by pulsed cavitational ultrasound therapy

Power variability in acoustic backscatter is established as a useful indicator of tissue damage production by pulsed cavitational ultrasound therapy. In in vivo experiments, backscatter variability during pulsed therapy exposures and tissue damage resulting from the exposures were determined. Power variability was found to be significantly higher for exposures that produced tissue damage than those that did not produce damage. A threshold criterion was determined that when applied predicted tissue damage with high correlation (>0.95) to the experimental results, despite changes in exposure conditions. This result indicates that dynamic bubble activity is a likely characteristic of therapeutically effective cavitation. Moreover, the findings suggest that changes in acoustic backscatter can be used to develop real-time feedback processes for optimizing cavitational ultrasound therapy.