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Camera in a
Pill offers cheaper, easier window on your
insides
Newswise — What if
swallowing a pill with a camera could detect
the earliest signs of cancer? The tiny
camera is designed to take high-quality,
color pictures in confined spaces. Such a
device could find warning signs of
esophageal cancer, the fastest growing
cancer in the United States.
A fundamentally new
design has created a smaller endoscope that
is more comfortable for the patient and
cheaper to use than current technology. Its
first use on a human, scanning for early
signs of esophageal cancer, will be reported
in an upcoming issue of IEEE Transactions on
Biomedical Engineering.
"Our technology is
completely different from what's available
now. This could be the foundation for the
future of endoscopy," said lead author Eric
Seibel, a University of Washington research
associate professor of mechanical
engineering.
In the past 30 years
diagnoses of esophageal cancer have more
than tripled. The esophagus is the section
of digestive tract that moves food from the
throat down to the stomach. Esophageal
cancer often follows a condition called
Barrett's esophagus, a noticeable change in
the esophageal lining. Patients with
Barrett's esophagus can be healed, avoiding
the deadly esophageal cancer. But because
internal scans are expensive most people
don't find out they have the condition until
it's progressed to cancer, and by that stage
the survival rate is less than 15 percent.
"These are needless
deaths," Seibel said. "Any screen that
detected whether you had a treatable
condition before it had turned into cancer
would save lives."
An endoscope is a
flexible camera that travels into the body's
cavities to directly investigate the
digestive tract, colon or throat. Most of
today's endoscopes capture the image using a
traditional approach where each part of the
camera captures a different section of the
image. These tools are long, flexible cords
about 9 mm wide, about the width of a human
fingernail. Because the cord is so wide
patients must be sedated during the scan.
The scanning endoscope
developed at the UW is fundamentally
different. It consists of just a single
optical fiber for illumination and six
fibers for collecting light, all encased in
a pill. Seibel acted as the human volunteer
in the first test of the UW device. He
reports that it felt like swallowing a
regular pill, and the tether, which is 1.4
mm wide, did not bother him.
Once swallowed, an
electric current flowing through the UW
endoscope causes the fiber to bounce back
and forth so that its lone electronic eye
sees the whole scene, one pixel at a time.
At the same time the fiber spins and its tip
projects red, green and blue laser light.
The image processing then combines all this
information to create a two-dimensional
color picture.
In the tested model the
fiber swings 5,000 times per second,
creating 15 color pictures per second. The
resolution is better than 100 microns, or
more than 500 lines per inch. Although
conventional endoscopes produce images at
higher resolution, the tethered-capsule
endoscope is designed specifically for
low-cost screening.
Using the scanning
device is cheap because it's so small it
doesn't require anesthesia and sedation,
which increase the cost of the traditional
procedure.
"The procedure is so
easy I could imagine it being done in a
shopping mall," Seibel said.
A wireless scope
manufactured by a different group,
originally designed to pass through the body
and detect intestinal cancer, is now being
marketed for esophageal cancer screening.
The competing technology comes in a pill
about the width of an adult fingernail and
twice as long. By contrast, the UW's
scanning fiber endoscope's dimensions are
about half as big and the device fits inside
a standard pill capsule. The pill could be
even smaller, Seibel said, but the
researchers chose a size that would be easy
to handle and swallow.
Another disadvantage of
wireless capsules is they only allow a
single fly-by view.
"You have no control over the other pill
once it's swallowed. It just flutters down,"
Seibel said. But since the UW scope is
tethered, the doctor can move it up and down
along the region of interest.
Only a small percentage
of people who get Barrett's esophagus, about
5 percent to 10 percent, develop cancer. So
any screening method must have a low price
to be cost-effective.
"The next big challenge
is to make this cheaply," Seibel said. The
researchers are negotiating a contract to
commercialize the technology. In the future
they hope to not only take pictures, but
also deliver treatments through the device,
and to apply it to other diseases.
The research was funded
by the National Cancer Institute and Pentax
Corp. Early funding was provided by the
Whitaker Foundation and the Washington
Technology Center. Co-authors at the UW are
Drs. Michael Kimmey and Jason Dominitz in
gastroenterology at the UW Medical Center;
Richard Johnston, C. David Melville and
Cameron Lee in mechanical engineering; Steve
Seitz in computer science and engineering;
and Robert Carroll, now in electrical
engineering and computer science at the
University of California, Berkeley.