AAPM: Researchers develop nano-based x-ray for imaging, radiotherapy
A team of nanomaterial scientists, medical physicists and cancer biologists at the University of North Carolina (UNC) has developed smaller, lower-cost x-ray tubes packed with sharp-tipped carbon nanotubes for cancer research and treatment. The technology was presented this week at the 2009 meeting of the American Association of Physicists in Medicine (AAPM), in Anaheim, Calif.
The researchers said the technology is being developed to image human breast tissue, laboratory animals, and cancer patients under radiotherapy treatment and to irradiate cells with more control than previously possible with conventional x-ray tubes.
Sha Chang, PhD, Otto Zhou, PhD, and colleagues at UNC at Chapel Hill have developed cold x-ray tubes that replace the tungsten filament with carbon nanotubes. Electrons are emitted from the tips of the nanotubes when a voltage is applied, according to the team.
"Think of each nanotube as a lightning rod on top of a building. The high electric field at the tip of the lightning rod draws the electric current from the cloud. Carbon nanotubes emit electrons using a similar principle," Chang said.
The group reportedly used the nanotubes to build micro-sized scanners and image the interior anatomy of small laboratory animals. Existing x-ray technologies have difficulty compensating for the blur caused by the creature's breathing. Mechanical shutters that open and close to block and release radiation are used to time x-ray pulses to correspond with breathing, but their speed is inadequate for small animals because of the creatures' extremely fast breathing and cardiac motion, the researchers said.
Chang and Zhou said that they have demonstrated that their carbon nanotubes, which can be turned on and off instantaneously, are fairly easy to synch up to equipment that monitors small animal breathing or heart rate.
The nanotube devices may also improve human cancer imaging and treatment. Breast tomosynthesis systems currently check for breast cancer by swinging a single large x-ray source around the target to take multiple images over the course of several minutes. Using nanotube x-ray sources lined up in an array instead, breast imaging could be done within a few seconds by electronically turning on and off each of the x-ray sources without any physical motion, Chang and Zhou suggested. This tomosynthesis imaging could improve patient comfort and boost image quality by reducing motion blur, the team suggested.
Using 25 simultaneous beams, the team produced images of growths in breast tissue at nearly twice the resolution of commercial scanners on the market.
This summer, the team will conduct a clinical test of a first-generation nanotube-based imaging system for high-speed image-guided radiotherapy. The prototype imaging system is being developed by Siemens Healthcare and Xinray, a joint venture between Siemens and a UNC startup company, Xintech.
The researchers said the technology is being developed to image human breast tissue, laboratory animals, and cancer patients under radiotherapy treatment and to irradiate cells with more control than previously possible with conventional x-ray tubes.
Sha Chang, PhD, Otto Zhou, PhD, and colleagues at UNC at Chapel Hill have developed cold x-ray tubes that replace the tungsten filament with carbon nanotubes. Electrons are emitted from the tips of the nanotubes when a voltage is applied, according to the team.
"Think of each nanotube as a lightning rod on top of a building. The high electric field at the tip of the lightning rod draws the electric current from the cloud. Carbon nanotubes emit electrons using a similar principle," Chang said.
The group reportedly used the nanotubes to build micro-sized scanners and image the interior anatomy of small laboratory animals. Existing x-ray technologies have difficulty compensating for the blur caused by the creature's breathing. Mechanical shutters that open and close to block and release radiation are used to time x-ray pulses to correspond with breathing, but their speed is inadequate for small animals because of the creatures' extremely fast breathing and cardiac motion, the researchers said.
Chang and Zhou said that they have demonstrated that their carbon nanotubes, which can be turned on and off instantaneously, are fairly easy to synch up to equipment that monitors small animal breathing or heart rate.
The nanotube devices may also improve human cancer imaging and treatment. Breast tomosynthesis systems currently check for breast cancer by swinging a single large x-ray source around the target to take multiple images over the course of several minutes. Using nanotube x-ray sources lined up in an array instead, breast imaging could be done within a few seconds by electronically turning on and off each of the x-ray sources without any physical motion, Chang and Zhou suggested. This tomosynthesis imaging could improve patient comfort and boost image quality by reducing motion blur, the team suggested.
Using 25 simultaneous beams, the team produced images of growths in breast tissue at nearly twice the resolution of commercial scanners on the market.
This summer, the team will conduct a clinical test of a first-generation nanotube-based imaging system for high-speed image-guided radiotherapy. The prototype imaging system is being developed by Siemens Healthcare and Xinray, a joint venture between Siemens and a UNC startup company, Xintech.