Noninvasive treatment may be on the horizon.

• Position: Brain Tumors

A first step toward a minimally invasive treatment of brain tumors by combining chemotherapy with heat administered from the end of a catheter has been taken by engineers at Duke University, Durham, N.C. Their proof-of-concept study demonstrates that it should be technically possible to treat brain tumors without the side effects associated with traditional approaches of surgery, systemic chemotherapy, or radiation.

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," explains Carl Herickhoff, a fourth-year graduate student at the Pratt School of Engineering. "The catheter would use ultrasound to first image the tumor, and then direct a high-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 4[degrees]C--enough to melt the liposome but not enough to damage surrounding tissue. No one has...