Focused ultrasound brain surgery has now been performed successfully on nine human patients. The technique can be used to make lesions deep in the brain, through the intact skull and skin, with extreme precision.
The technique was tested on nine patients with chronic debilitating pain. The traditional treatment involves destroying a small part of the thalamus, a structure that relays messages between different brain areas.
In the procedure, ultrasound beams are focused on a specific point in the brain; the exact location depends on the condition being treated. The small portion of brain tissue at the focus -- about the size of a rice grain -- absorbs the energy and converts it to heat. The entire system is integrated with a magnetic resonance scanner, which allows neurosurgeons to make sure they target the correct piece of brain tissue.