CHAPEL HILL – In a basement laboratory in Phillips Hall, Otto Zhou is working to harness the power of microscopic tubes to better see inside the human body and treat cancer.
The physics professor at the University of North Carolina at Chapel Hill, along with physics professor Jianping Lu, has figured out how to leverage carbon nanotubes – one of the hottest trends in science right now – to create smaller, less energy-demanding X-rays. The breakthrough is revealing potential applications in new medical imaging technology.
Already, XinRay Systems, a spinoff company that Zhou helped create, is working with Siemens AG to develop a new X-ray computer tomography image-based radiation system for treating cancer. That system will soon go into clinical trials at UNC Hospitals.
And he and his team are working to create a mammogram machine that would be able to scan a breast in two seconds, down from 30 seconds, and they are close to creating an improved system for scanning baggage at airports.
Zhou also has received $2 million from the National Cancer Institute through the American Reinvesment and Recovery Act to create a new system for radiating brain tumors that minimizes damage to surrounding healthy cells.
“X-ray is great,” he says of the currently available technology. “But there are things that can be made better.”
Other work under way
Over the past several years, Zhou and his team have received more than $5 million in grants from various sources, including the National Cancer Institute and National Institutes of Health, for studying ways to use carbon nanotubes to improve X-ray technology.
Carbon nanotubes are microscopic arrangements of carbon atoms into tubular structures. Under an electron microscope, they look like tiny hairs, and because of their tiny size it takes less energy to compel electrons to jump off the carbon nanotubes – an important characteristic for X-ray machines.
X-ray images are created when negatively charged electrons blast an anode, which then emits the radioactive X-rays. But getting electrons to fire on an anode is not easy. At the particle level, atoms join by sharing electrons. It’s a bond the atoms want to make and are reluctant to give up. It takes a burst of energy to make the electrons break away.
In a traditional X-ray machine, energy is delivered in the form of heat. Much like a light bulb, a filament is heated to more than 1,800 degrees Fahrenheit to cause the electrons to bombard the anode.
But because of such heat, it is impossible to line up multiple X-ray machines next to each other. This means that if doctors want images from different angles, they need to move the X-ray machine, and the chance of images being distorted or blurred, because the person moves, increases.
A normal CT scanner gets around the issue by rotating around a person, taking multiple two-dimensional X-ray images to give a clear, three-dimensional picture of an organ.
Zhou gets around the heat issue by using carbon nanotubes instead of a filament. Because the nanotubes are so small, the bond between the atoms is weaker than with the denser filament in traditional X-rays. That means Zhou needs less energy, in this case an electric charge, to cause the electrons to break away, and as a result he is able to place multiple X-rays next to each other.
And even though the nanotubes are about 1/10,000 the size of a human hair, Zhou and his team are still able to manipulate the nanotubes to maximize their value. Post doctoral researcher Xiomara Calderon-Colon mixes the nanotubes in a solution, a nanotube soup if you will, implants them onto a glass-current board and uses electronic fields to make the tubes stand up on the current board. The electric charge that causes the electrons to jump off the tubes is drawn to standing objects, much in the way lightning is drawn to a tree.
The new technology can mean faster and easier CT scans because multiple images can be shot at once. And the mammogram prototype will shoot dozens of scans from different angles all at the same time.
Good news for cardiologists
The ability to shoot images simultaneously would be a boon for cardiologists. It often is difficult to get a good image of the heart because it is constantly moving, says Cam Patterson, chief of the Cardiology Department at UNC Hospitals and a collaborator on some of Zhou’s research. This new technology would allow cardiologists to snap X-ray images around the entire heart at the same time and over the same cycle, giving a more accurate picture.
And for cancer treatments, Zhou believes the new technology could be used to better direct radioactive waves at a tumor without hurting other cells.
“The problem is not killing the tumor,” he says. “It is sparing the regular tissue.”
Reporter e-mail: jgallagher@bizjournals.com.