A system for treating tissue within a body is configured to deliver a first level of ultrasound energy to a target tissue region for a first duration resulting in the generation of microbubbles in the target tissue region, determine one or more characteristics of the target tissue region in the presence of the microbubbles, and deliver a second level of ultrasound energy to the target tissue region for a second duration, wherein one or both of the second energy level and the second duration are based, at least in part, on the determined one or more characteristics of the target tissue region.