A Capsule Camera Instead of a Colonoscopy?
TUESDAY May 10, 2011 -- A new technology that uses a remote-controlled capsule camera to scan the inside of the colon may one day be an alternative to colonoscopy, a new study suggests.
Researchers from Japan's Osaka Medical College have developed a "self-propelled capsule endoscope" that can be inserted into the anus and driven through the colon via remote control and a magnetic field, capturing images along the way.
Similar capsule cameras are currently used to scout out problems in the small intestine, said Dr. Durado Brooks, director of colorectal cancer for the American Cancer Society. Patients swallow the capsule, which then moves through the digestive system much in the same way that food does, recording images of the inside of the intestine.
But capsules haven't worked as well in looking for problems in the colon, Brooks noted.
Part of the reason is that the colon has many nooks and crannies. During a colonoscopy, physicians move an endoscope, or a flexible tube containing a light and a camera, around inside the colon to get a full view, something that can't be done easily with capsule cameras.
"The colon is not a smooth tube. It's not like a pipe," Brooks said. "It's a convoluted, muscular tube with a lot of folds and crevices. The capsule camera is going to need to be able to visualize behind the folds and into the crevices."
Also, the colon -- though at about 4.5-feet long is considerably shorter than the 21-feet of the small intestine -- is larger in diameter than the small intestine, making getting a full 360 degree view more difficult.
Finally, capsule cameras currently in use take a long time to move through the digestive tract. To get a good view of the colon, it would have to be empty of waste material, including stool and mucus. Even if a patient undergoes an enema, waste material that hasn't yet made its way to the colon may end up obscuring the view by the time the capsule camera gets there.
According to the new study, Japanese researchers went in the other way, so to speak.
They first injected water into the anus, and then inserted the pill camera. Controlling the device by remote control, they obtained images using a real-time monitoring system.
The capsule moved smoothly through the colon and could be removed from the anus easily and safely, according to the study.
"This trial demonstrates the feasibility to control and maneuver the capsule in the colon of a human who is awake," study author Dr. Takanori Kuramoto, said in a Digestive Disease Week news release. "Our study is the first trial of an actively propelled video capsule in the human colon, and we expect it will lead to the development of a commercial system to propel the capsule in a way that lets doctors visualize the entire gastrointestinal tract from esophagus to anus."
The findings were presented Sunday at Digestive Disease Week in Chicago.
Brooks called the findings a "proof of principle," meaning that researchers have shown using camera capsules to scan the colon is possible. But far more research needs to be done before the devices should actually be put to use, including determining that they work as well as current screening, such as colonoscopy.
"The next step is determining whether or not it can give an accurate assessment of what is going on in the colon," Brooks said.
Even if it can, capsule camera will never replace colonoscopies, he said. When physicians detect abnormalities such as polyps that can develop into cancer during a colonoscopy, they'll often remove the polyps right then and there.
If a capsule detects polyps, the patient is going to have to undergo a colonoscopy afterward to get the polyps treated and biopsied.
"You can't do that through a capsule," he said.
Dr. Joel Brill, chief medical officer for the American Gastroenterological Association's Digestive Health Outcomes Registry, said any device that has the potential to make colorectal cancer screening more tolerable is a positive development.
"This looks like it's a feasibility study," Brill said. "As the researchers have said, the next step is to see if this can actually be commercialized or be done outside of a research setting."
The American Cancer Society has more on colorectal cancer.
Posted: May 2011