A Precisely Targeted Attack on Eye Cancer

Using ultrasound waves to reach a tumor at the back of the eye (left), the team plans to generate only enough heat to release drugs at the tumor site (right). (Images courtesy of Shutao Wang)

A team of GW researchers is working to harness the heat of ultrasound waves to develop a new, highly targeted treatment for a childhood eye cancer.

The disease, retinoblastoma, is a cancer of the retina—the collection of nerve cells at the back of the eye that sense light and transmit images to the brain via the optic nerve. About 300 children each year in the United States are diagnosed with the disease, according to the American Cancer Society; in some cases, retinoblastoma may develop in both eyes.

Treatments exist, but the group of scientists from GW’s School of Engineering and Applied Science and the School of Medicine and Health Sciences are designing a therapy they hope will be much more controlled and precisely targeted, capable of hitting a bull’s eye smaller than a grain of rice. The approach, they say, will be less likely to result in damaged vision or loss of the eye, and result in fewer side effects.

Shutao Wang, a doctoral student in the Department of Electrical and Computer Engineering, says the focused ultrasound approach is akin to using a magnifying glass to funnel light energy and burn a leaf.

The team’s idea is to isolate a small treatment area by combining the ultrasound waves with a chemotherapy drug encapsulated in tiny, heat-sensitive packages. The beam of ultrasound waves would get increasingly refined—and higher-energy—as it reaches the tumor in the back of the eye, generating just enough warmth at the tumor site to trigger the release of the drug at that location.

Although the drug would be circulating in the body’s bloodstream, its packaging would prevent it from impacting the rest of the body.

That approach would join other budding treatments that attempt to maximize therapy and minimize side effects. Other treatments currently available—including radiation therapy, laser therapy and chemotherapy—can risk damage to the retina and adjacent eye tissues, and can result in further tumors or other potentially life-threatening side effects. In advanced cases in which the tumor is large or resistant to treatment, the cancerous eye often is removed as a life-saving measure.

The research, which is supported by a grant from the GW Institute for Biomedical Engineering, received a boost in May when Mr. Wang won a global student competition by Weidlinger Associates, a structural engineering and applied mechanics consultancy. Students were asked to propose uses for the company’s simulation software, PZFlex.

Mr. Wang won a laptop and a one-year license of the software, which he’s now using to model the eye, simulate the impact of ultrasound waves on ocular tissue, and test the amount of power needed to generate just the right amount of heat at the tumor site. The findings then can be validated on an animal model and, they hope, eventually humans.

The research team is led by engineering professor Vesna Zderic and Craig Geist, chair of the Department of Ophthalmology. Besides Mr. Wang, the team includes ophthalmology residents Ji Liu and Sankaranarayana Mahesh.

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