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. "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.
In a series of experiments in animal models and simulated tissues, the researchers demonstrated that they could build a catheter thin enough to be placed in one of the brain's main blood vessels that was capable of serving the dual purpose of visualization and heating.
"Taken as a whole, the results of these experiments, in particular the clarity of the images and ability to increase temperature with the same catheter, lead us to believe that the ultimate creation of a practical intracranial ultrasound catheter is possible," said Stephen Smith, director of the Duke University Ultrasound Transducer Group and senior member of the research team.
MEDICA.de; Source: Duke University