Therapeutic ultrasound -- also known as HIFU (i.e. high-intensity focused ultrasound) -- involves focusing of ultrasound in a manner similar to how a magnifying glass focuses light. The ultrasound waves are created by a transducer (a device that converts electrical energy into ultrasound energy). The waves can pass through non-target tissue without ill effects, but destroy the target tissue at the focal point (i.e. the point of highest intensity). Over the last two decades, HIFU has been proven in tens of thousands of procedures worldwide for a wide range of clinical applications including fibroids, prostate, kidney, cardiac, and various other tumors.