Such a wireless (news
- web
sites), video-equipped capsule -- about half the size of a grape
-- has been swallowed and tested in the first human volunteer, they
reported here Monday at the annual Digestive Disease Week
conference.
Using a radio-guided control box, the researchers were able to
"move the capsule, go backwards and look at something again," said
Dr. Annette Fritscher-Ravens of the University of London.
"It's the future of wireless capsule therapy," she said.
Until recently, patients with unexplained gastrointestinal
illness had only a few options when it came to diagnosis -- CT scans
or MRI, endoscopy, or surgical interventions. Each has its
limitations, and researchers have long sought a method of clearly
viewing the inside of the entire length of the gastrointestinal
tract without having to resort to surgery.
Within the last decade, researchers developed tiny,
video-equipped capsules that are swallowed and then passed through
the body via the normal movement of the gut.
But relying on the gut to propel the capsule forward has had its
problems.
"Sometimes it runs quickly or runs very little," Fritscher-Ravens
said, which can keep the capsule sitting for hours in an area of
little interest, while speeding it past areas doctors want to linger
on.
What was needed was a method of controlling the capsule from the
outside.
Fritscher-Ravens and her colleagues say they have patented just
such a method. Using technology very similar to that found in TV
remotes or electronic car-keys, they attached tiny electrodes to the
front and rear portions of the video capsule, along with a tiny
antenna. Using a drive/reverse switch, they have been able to steer
and propel the capsule through the gut, lingering wherever a lesion
or other suspicious formation occurs.
After first testing the device in pigs, "we were able, in man, to
steer the capsule backwards and forwards and stop it,"
Fritscher-Ravens told reporters at the meeting.
Safety was always a concern, but the device only requires 5
milli-amps of power. "This is very, very little power -- much less
power than would interfere with a heart rate or anything," the
researcher said.
The capsule, which is meant to be disposable, safely passes
through the gut and is flushed away with a regular bowel movement.
Speaking with Reuters Health, Fritscher-Ravens and co-researcher
Dr. C. Paul Swain (who was the first human test subject) said they
expect the device to go through further trials and then be submitted
for approval by the U.S. Food and Drug Administration (news
- web
sites) within the next two to three years.
They have high hopes for the capsule. Someday, the device might
be made to travel through the gut and grab tiny pieces of tissue for
biopsy. It might even be used to treat disease, possibly eliminating
the need for surgery, according to the researchers.
"Right now, with this capsule we can see (a lesion), but we can't
treat it," Fritscher-Ravens said. However, she envisages a future
where "you can swallow two capsules that come together, and then you
can just fire a laser at the lesion."
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