One curious engineer, 44,500 brain tumors

In science fiction stories, villains zap victims with a shrink-ray. But Professor Otto Zhou of the UNC-Chapel Hill has become a hero by shrinking the X-ray machine itself.

Zhou and his team are applying carbon nanotube X-ray technology invented at UNC to a promising experimental microbeam radiation therapy now housed in massive synchrotrons — facilities larger than most football stadiums. The team has nearly $2 million for that work, courtesy of a National Cancer Institute award from American Recovery and Reinvestment Act funding.

Zhou and Sha Chang, associate professor of radiation oncology, hope to be the first to deliver the same radiation dose with a doughnut-shaped X-ray source ring placed around the patient’s head. Pre-clinical studies conducted at large synchrotron facilities in the United States and France have shown the therapy has the potential to zap the tumor, but spare the surrounding normal brain tissue.

About 44,500 Americans are diagnosed with brain tumors annually; only 30 percent survive. “We’ve made little progress in 30 years in the survival rate,” Zhou says. “We want to build a system to cure brain tumors.”

Zhou is the David R. Godschalk Professor of Physics and Astronomy. Hetalks like a builder; he is an engineer fascinated by the carbon nanotube. This single layer of carbon atoms is linked in a hexagon pattern —like a roll of chicken wire but as hard as diamond and as tough as graphite. And so very tiny — about 10,000 times smaller than the diameter of a human hair.

X-ray machines using carbon nanotubes instead of hot cathodes would be smaller, easier to use and more accurate. Nanotubes can fire all at once, from different angles, in one-millionth of a second, quick enough to capture a still image of a beating heart. No more blurred images when the patient breathes or shifts position. No more painful compression of the breast to take a mammogram.

The images are so accurate and fast that oncologists, for the first time, could “see” the tumor during treatment. The technology also has the potential to allow radiologists to detect cancer such as human breast cancer at an earlier stage than is possible today. Based on this technology, a new digital mammography scanner is under development at Zhou’s lab. Grants from the National Cancer Institute and the Department of Defense sponsor the project.

The University Cancer Research Fund paid for equipment used to build another copy of a system developed in Zhou’s lab so that other UNC researchers can use it for pre-clinical medical research. A new imaging-guided radiation therapy device built by XinRay Systems, a start-up company Zhou formed in collaboration with Siemens Medical Solutions of Germany, will be tested in a clinical trial directed by Chang at the North Carolina Cancer Hospital, the first U.S. test site.

Zhou has big ideas about the tiniest materials. “As engineers, we like to see ideas become something useful, more than just a stack of papers. We want our work to translate into something useful to society.”

Otto Zhou is one curious engineer who’s turning science fiction into fact … and creating hope for patients with one of the hardest-to-treat diseases on the planet.