Potential for noninvasive brain tumor...( DURHAM N.C. -- Duke University engi...),Health

DURHAM, N.C. -- Duke University engineers have taken a first step toward a minimally invasive treatment of brain tumors by combining chemotherapy with heat administered from the end of a catheter.

The proof-of-concept study demonstrated that it should be technically possible to treat brain tumors without the side effects associated with the traditional approaches of surgery, systemic chemotherapy or radiation.

The bioengineers designed and built an ultrasound catheter that can fit into large blood vessels of the brain and perform two essential functions: provide real-time moving 3-D images and generate localized temperature increases. The researchers envision using this system in conjunction with chemotherapy drugs encased in heat-sensitive microbubbles called liposomes.

"Physicians would inject drug-carrying liposomes into a patient's bloodstream, and then insert a catheter via a blood vessel to the site of the brain tumor," said Carl Herickhoff, fourth-year graduate student at Duke's Pratt School of Engineering and first author of a paper appearing in the journal Ultrasonic Imaging. "The catheter would use ultrasound to first image the tumor, and then direct a higher-power beam to generate heat at the site, melting the liposome shells and releasing the chemotherapy directly to the tumor.

"The temperature increase would be about four degrees Celsius enough to melt the liposome, but not enough to damage surrounding tissue," Herickhoff said. "No one has tried this approach before in the brain."

The American Cancer Society estimates that more than 21,000 new brain tumor cases were diagnosed in 2008, with more than 13,000 patients dying. This represents about two percent of all cancer deaths.

The researchers said that a minimally invasive approach to treating this cancer would be preferable to the conventional methods, which have drawbacks and side effects of their own.

"Surgery is invasive,
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