Capsule camera's fantastic voyage captures digestive tract

'Gut cam' gives first look at entire small intestine

An announcement this month that researchers have devised a miniature camera-in-a-capsule that can traverse the entire digestive system made big news, but the revolutionary imaging technology is several years away from the market.

The ultra-small image sensor, which was developed by Pasadena, CA-based Photobit, can be contained in an ingestible capsule and swallowed like a pill, according to a company statement and press reports. Patients wear an antenna array and a wireless recorder on a waist belt, which picks up signals transmitted by the capsule during its six-hour trip.

Endoscopy procedures for diagnosing and treating cancer and other digestive ailments are now routine, but physicians have been limited in their ability to visualize the lower half of the small intestine without significant discomfort to the patient. Developers of the camera-in-a-capsule plan the first human trials later this year in the U.S.

The capsule camera cannot be stopped or steered like existing endoscopes, nor can it take biopsies or remove intestinal polyps. It sees only one direction as it goes through the intestines. Some observers were skeptical of image quality, although Dr. Paul Swain of the Royal London Hospital, who directed the tests, told the Associated Press the color images were "pretty good."

"The small intestine is a tube, so it really doesn't matter which way the capsule is pointing," Swain said.

Virtual endoscopy using CT technology is limited to the colon because the small bowel is much longer and more circuitous, said Dr. Judy Yee, assistant professor of radiology at the University of California, San Francisco, and chief of CT and GI radiology at the San Francisco Veterans Affairs Hospital.

"There is no good way to reliably distend the small bowel, to stretch it out," Yee said. "The type of pathology colonoscopy is useful for finding is malignancy, and malignancy is rare in the small bowel."

Yee said she would like to see more trials of the "gut cam."

"It's an interesting concept," Yee said. "but there might be obstacles to its being only foward-looking. You could get debris obscuring the camera. Or, if you have a partial or complete stricture, the capsule could swirl around a long time. It could cause obstruction itself."

Yee said that with the instance of small bowel malignancy so low, the gut cam advantage might not be great.

"You wouldn't use it for screening," she said.

When it is ready for sale, the disposable capsule camera will be marketed by Israel-based Given Imaging, a developer of platform technology for GI diagnostics and therapy. Given has designed a computer workstation that processes the data and produces a 20-minute video clip of the camera's images.