New Technology Tested At Stanford Offers Unique View Inside Small Intestines

Jacques Van Dam, MD, PhD, professor of medicine at the Stanford School of Medicine, recently used the miniature camera on his second medical center patient. The first two patients are part of a multi-center clinical trial of the device-called the M2A capsule-in people who need regular transfusions due to bleeding. In a separate trial, Stanford researchers will test the device in anemic patients who do not yet need transfusions.

Doctors suspect internal bleeding when patients have consistently low levels of hemoglobin (the blood-born protein that carries oxygen). "Usually the bleeding is in the stomach or colon," Van Dam said. "But sometimes we can't find the source." Often these patients must get regular transfusions to make up for the lost blood.

To detect bleeding in the throat, stomach or colon, doctors use an endoscope-a camera on the end of a long, flexible rod. But endoscopy may fail to show the source of bleeding, leading doctors to suspect the small intestine. With no device for viewing inside the deepest portions of the small intestine, however, exploratory surgery is the only way to know for sure-no small feat, given the 20-foot length of the organ. "[The M2A capsule] lets us see what's happening in the small intestine for the first time," Van Dam said.

In preparation for the procedure, a patient fasts for eight hours to prevent food in the small intestine from obscuring trouble spots. The patient then swallows the vitamin-sized capsule, which encases four tiny flashing lights, a color camera, a battery and an antenna. The patient has a receiver taped to his or her abdomen to track the capsule's progress, recording two images per second. The capsule transmits images via radio frequencies to a Walkman-sized device worn on a belt along with a battery pack. Stanford's second patient to test the device, Leland McGraw, 77, swallowed the camera without a hitch. "I didn't feel it," he commented after it went down, adding that the receivers and belt were comfortable.

Two hours after swallowing the M2A capsule, patients can drink clear liquids. At four hours, they can eat solid food. Patients go about their daily business during the eight-hour procedure, careful not to dislodge the receivers or interfere with the battery pack and recorder. Eight hours after swallowing, the patient removes the belt and sensors, and simply forgets about the small plastic camera. "Patients don't have to retrieve the camera," said Van Dam. It simply completes its path through the digestive tract and is passed in stool.

The next day, the patient returns the belt, battery pack and recorder to the doctor, who downloads the video images into a computer. Software lets the doctor view the entire video of the camera's travels and save selected images. Snapping two images per second, the camera doesn't miss much. Doctors may be able to spot tumors, ulcers and bleeding. "More often than not, it's bleeding that we find," said Van Dam. Upon identifying the source, a surgeon can then remove the damaged portion of small intestine.

Although the capsule's components are based on existing technology, nobody has sent a camera through the digestive tract. "The fact that it worked is a big breakthrough," Van Dam said. "There's never been anything like this." Not only does it traverse the highly acidic stomach, but the camera successfully peers through the soupy contents of the small intestine and takes pictures as it tumbles along. "It doesn't matter if you're looking where you're going, or where you've been," said Van Dam, explaining that the tumbling motion isn't a problem.

The M2A capsule is as cost effective as endoscopy, said Van Dam, and could prevent expensive and painful surgery. Each capsule costs $450 and the one-time software purchase runs under $30,000. "It saves money if you consider that these people are bleeding and getting multiple endoscopies and transfusions, or more invasive procedures," Van Dam added.

Stanford University Medical Center integrates research, medical education and patient care at its three institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children's Hospital. For more information, please visit the Web site of the medical center's Office of News and Public Affairs at http://mednews.stanford.edu