Narrator: This is Science Today. About three percent of us have an aneurysm in our brains -- a weakness in a blood vessel that's waiting to rupture and cause damage or death.

Halbach: It's kind of like the old inner tube tires, there can be a little weakness that develops.

Narrator: Dr. Van Halbach is a neurosurgeon at University of California, San Francisco.

Halbach: Like any balloon, the larger the diameter, the thinner the walls, and at some point the aneurysm becomes so weak and fragile that the blood leaks out of the aneurysm.

Narrator: But there's a new technique to repair aneurysms -- if they're caught in time -- without surgery. An extremely thin tube is run from an artery in the groin up into the brain. At the end of the tube is a tiny detachable platinum coil as thin as a thread.

Halbach: If there's a weakness in the blood vessel, a little out-pouching, we actually insert the coil into the weak spot. The coil itself disturbs the blood enough to where a clot forms.

Narrator: The clot acts sort of like a patch, strengthening the wall of the blood vessel. Using the coils, Halbach and his fellow surgeons have treated several hundred aneurysms successfully. For Science Today, I'm Steve Tokar.