Physicians currently insert camera-equipped endoscopes into patients to hunt visible abnormalities, such as tumours, in the gastrointestinal tract and internal organs. Huikai Xie, an associate professor of electrical and computer engineering, is working on replacing the cameras with scanners that see beneath the surface of tissues, revealing abnormal groups of cells or growth patterns before cancerous growths are big enough to be visible.
‘Right now, endoscopes just take pictures of the surface tissue. So, if you see some injury, or abnormality, on the surface, that’s good,’ said Xie. ‘But most of the time, particularly with cancer, the early stages of disease are not so obvious. The technology we are developing is basically to see under the surface, under the epithelial layer.’
Experiments with Xie’s scanning micro-endoscopes on animal tissue have been promising, although his devices have yet to be tested in people. The pencil-sized or smaller-sized endoscopes could one day allow physicians to detect tumours at earlier stages and remove tumours more precisely.
With current camera-equipped endoscopes, once doctors spot abnormalities, they typically perform a biopsy and then send the tissue to a laboratory. However, biopsy is risky and may cause bleeding and even trauma. Also, it usually takes a couple of days to receive the analysis of the biopsy sample from the laboratory. If it is cancerous, surgeons may attempt to remove the abnormality and surrounding tissue, using either endoscopes equipped for surgery or traditional surgical methods.
Xie’s endoscopes replace the cameras with infrared scanners. The heart of his scanner is a tiny motorised MEMS mirror that pivots back and forth to reflect a highly focused infrared beam onto tissue.
Computers process the return signal from the endoscopes, transforming it into a 3D image of the surface tissue and the tissue beneath. One scanner even produces a 360-degree image of all the tissue surrounding the endoscope. Doctors or other trained observers can then search the image for abnormalities or suspicious growth patterns.
According to Xie, his scanners have achieved a resolution of 10 microns - or 10 millionths of a metre - in laboratory tests, more than 10 times higher resolution than the only other non-camera-based endoscopes on the market, which use ultrasound technology. The high-resolution image also includes depth information, so the risky biopsy can be more specific to avoid randomness or even completely avoided.
He said that doctors could use the endoscopes not only for diagnosis, but also for treatment and surgery. Currently, said Xie, during operations doctors rely on static MRI or CT images of tissue obtained before the operation begins. However, his scanners make images available in real time. That would be particularly useful for regions of the body where removing as little tissue as possible is paramount, such as in brain surgery, he added.
‘We are trying to couple this imaging probe with cutting tools, so that when surgeons begin cutting they know exactly what’s in front of them,’ said Xie.
He recently launched a company, Gainesville-based WiOptix, to speed the commercialisation of the scanning technology.