When Princess Diana's limo crashed in 1997, she might have lived if paramedics could have swiftly stopped the massive internal bleeding in her chest, lungs, and head. Now a group of scientists at the University of Washington in Seattle has developed an experimental technology that could rapidly seal off an accident victim's damaged blood vessels without the need for a single incision.
Doctors commonly stop hemorrhaging with powerful electrical currents that shrink blood vessels and induce blood clots, but the technique, called electrocautery, works only for wounds close to the surface. High-intensity ultrasound--waves having frequencies of one to 10 megahertz, far above the highest audible sounds--offers far more flexibility, claims bioengineer Shahram Vaezy. His team has found a way to focus very-high-energy ultrasound at precise sites deep within an injured area. The ultrasound beam is absorbed by the tissue and converted to intense, localized heat, which stops the bleeding by ...
