New capsule camera to detect early stages of cancer

The hi-tech transparent device is about the size of a large multivitamin pill and contains a rapidly rotating laser that shines a beam of near-infrared light onto the wall of the oesophagus, the pipe that carries food to the stomach.

Researchers at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH) said the system has several advantages over traditional endoscopy.

"This system gives us a convenient way to screen for Barrett's that doesn't require patient sedation, a specialised setting and equipment, or a physician who has been trained in endoscopy," said researcher Gary Tearney.

"By showing the three-dimensional, microscopic structure of the esophageal lining, it reveals much more detail than can be seen with even high-resolution endoscopy," said Tearney in a statement.

The system involves a capsule containing optical frequency domain imaging (OFDI) technology - a rapidly rotating laser tip emitting a beam of near-infrared light and sensors that record light reflected back from the esophageal lining.

The capsule is attached to a string-like tether that connects to the imaging console and allows a physician or other health professional to control the system.

After the capsule is swallowed by a patient, it is carried down the oesophagus by normal contraction of the surrounding muscles. When the capsule reaches the entrance to the stomach, it can be pulled back up by the tether. OFDI images are taken throughout the capsule's transit down and up the oesophagus.

Researchers tested the system in 13 unsedated participants - six known to have Barrett's oesophagus and seven healthy volunteers. The physicians operating the system were able to image the entire oesophagus in less than a minute, and a procedure involving four passes - two down the oesophagus and two up - could be completed in around six minutes.

A typical endoscopic examination requires that the patient stay in the endoscopy unit for approximately 90 minutes.

The detailed microscopic images produced by the OFDI system revealed subsurface structures not easily seen with endoscopy and clearly distinguished the cellular changes that signify Barrett's oesophagus. Study participants who had previously undergone endoscopy indicated they preferred the new procedure.

"The images produced have been some of the best we have seen of the oesophagus," said Tearney.