Technology Review reported that carbon nanotubes are at the heart of a new X-ray machine that is slated for clinical tests later this year at the University of North Carolina Hospitals. The machine has the potential perform much better than those used today for X-ray imaging and cancer therapy. It speeds up organ imaging, takes sharper images and could increase the accuracy of radiotherapy so it doesn’t harm normal tissue.
Instead of a single tungsten emitter used with regular X-ray machines, the UNC team uses an array of vertical carbon nanotubes that serve as hundreds of tiny electron guns. While tungsten requires time to warm up, the nanotubes emit electrons from their tips instantly when a voltage is applied to them.
Taking clear, high-resolution X-ray images of body organs is much easier with the new multi-beam source, says physics and materials science professor Otto Zhou.
The TR story contrasts Zhou’s machine with s CT scanner. As a CT system rotates, it takes hundreds of pictures that are synthesized to reconstruct a 3-D image. Instead of turning, Zhou’s system turns multiple nanotube emitters on and off in sequence to take pictures from different angles.
Because the emitters turn on and off instantaneously, says Daniel Kopans, director of breast imaging at Massachusetts General Hospital, the system should be able to take more images per second. This faster exposure, Kopans says, should reduce blur, much as a high-speed camera captures ultrafast motion.
There also is hope that this technology could also lead to more accurate radiation treatments for conditions such as cancer, and may permit on-the-fly adjustments while a treatment is underway.