Ultrasound Treatment Takes On Cancer’s Toughest Tumors
23rd December 2025
FOR MANY YEARS, doctors and technicians who performed medical ultrasound procedures viewed bubbles with wary concern. The phenomenon of cavitation—the formation and collapse of tiny gas bubbles due to changes in pressure—was considered an undesirable and largely uncontrollable side effect. But in 2001, researchers at the University of Michigan began exploring ways to harness the phenomenon for the destruction of cancerous tumors and other problematic tissue.
The trouble was, creating and controlling cavitation generated heat, which harmed healthy tissue beyond the target area. Zhen Xu, who was working on a Ph.D. in biomedical engineering at the time, was bombarding pig heart tissue in a tank of water with ultrasound when she made a breakthrough.
The key was using extremely powerful ultrasound to produce negative pressure of more than 20 megapascals, delivered in short bursts measured in microseconds—but separated by relatively long gaps, between a millisecond and a full second long. These parameters created bubbles that quickly formed and collapsed, tearing apart nearby cells and turning the tissue into a kind of slurry, while avoiding heat buildup. The result was a form of incisionless surgery, a way to wipe out tumors without scalpels, radiation, or heat.