Curious Engineer
Brain Tumors To Zap
Otto Zhou’s tiny carbon nanotubes offer new hope to patients diagnosed with brain tumors.
Gallery
In science fiction stories, the villain zaps his victims with a shrink-ray, cutting them down to size. But Professor Otto Zhou of UNC-Chapel Hill’s College of Arts and Sciences has become a hero by shrinking the X-ray machine itself.
Otto Zhou is the David Godschalk Distinguished Professor of Physics and Materials Science.
Zhou has been awarded nearly $2 million in American Recovery and Reinvestment Act (ARRA) funding from the National Cancer Institute to apply carbon nanotube X-ray technology invented at UNC to a promising experimental microbeam radiation therapy now housed in massive synchrotrons – facilities larger than Kenan Stadium. Using carbon nanotechnology, Zhou and Sha Chang, associate professor of radiation oncology, hope to be the first to deliver the same radiation dose with a desktop-size device. About 44,500 Americans are annually diagnosed with brain tumors; 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 & Chang propose to use a doughnut ring to deliver radiation at the high rate comparable to large synchrotron facilities.
Zhou talks like a builder because he is an engineer fascinated by carbon and its unique properties. Zhou got the idea for the shrinking X-ray machine in 2000, while brainstorming uses for carbon nanotubes over a Philly cheese steak with fellow investigator Jianping Lu, a UNC physics professor.
Zhou & Lu kicked around the idea of using nanotubes for X-rays, jotting down some notes on a napkin.
What are carbon nanotubes? The tube is a single layer of carbon atoms linked up in a hexagon pattern – like a roll of chicken wire. Only these tubes are 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.
Zhou sees big possibilities – in medicine, security and engineering—in tiny carbon nanotubes.
By using carbon nanotubes instead of hot cathodes, for example, new X-ray machines would not only be smaller and easier to use, they would also capture more accurate 3-D images. Nanotubes can be placed to fire all at once, from different angles, in one-millionth of a second. No more wasted X-rays and blurred images when the patient breathes or shifts position. No more painful compression of the breast to take a mammogram.
This multipixel technology is quick enough to capture a still image of a beating heart.
The images are so accurate that, in theory, they could attack cancer cell by cell because oncologists, for the first time, could “see” the tumor during treatment. More realistically, the high-resolution images can be used during radiation treatment, concentrating the dose on the tumor without damaging healthy tissue. Conventional CT scans interfere with radiation treatment and can’t be used at the same time.
The University Cancer Research Fund paid for equipment to build a copy of a system developed in Zhou’s lab.
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.” Zhou, who holds about 50 issued or pending U.S. patents, collaborated with Siemens Medical Solutions of Germany to form XinRay Systems, a small start-up company in Research Triangle Park that employs 11 people, including recent UNC graduates.
The ARRA grant will create jobs at UNC and XinRay, manufacturer of the X-ray source array. Moritz Beckmann is the CEO of XinRay.
But Zhou’s ideas for carbon nanotube technology go beyond medical uses. So he helped form Xintek, a UNC spinoff to explore uses beyond the medical X-ray. Engineers could use carbon nanotube technology to check the structural integrity of bridges and buildings much more easily. These tiny tubes may also revolutionize airport security systems by making X-ray machines faster and more accurate. Lines at baggage checkpoints would be shorter, and security personnel would see clear 3-D images of what’s inside each bag. 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.
