Swallow-able solutions: Pill-sized camera helps detect America’s fastest rising cancer

Saying “cheese,” or even smiling for this camera. Might be a bit challenging once it’s down your esophagus.

Called the tethered capsule endoscope (TCE), this camera is not only the smallest of its kind, but is also an innovative tool for the early detection of esophageal cancer, which is currently America’s fastest growing cancer.

Eric Seibel, a professor of mechanical engineering who helped develop the endoscope, said the idea didn’t come about too long ago. “It was an idea that we had between myself and a medical doctor at the University of Washington,” he said. They began designing the cameras in 2004.

Endoscopy, or viewing the inside of the body with a flexible tube attached to an optical device, existed as a medical procedure long before the idea of the TCE came about. The doctors at the UW patented the TCE with hopes of advancing beyond the barriers in endoscopy technology. “We had heard about the capsule that you can swallow, but it’s quite big and there are lots of problems with using that,” Seibel said. “We can do better with our technology.”

Only 18mm long and 6.35mm in diameter, the TCE is significantly smaller than the 26mm-by-11mm traditional wireless endoscope. “We think we have the smallest camera that can be made right now,” Seibel said.

The purpose of the tether (the plastic wire attached to the camera) is to provide a safer alternative to wireless endoscopes. “Wireless is the problem: It gets stuck in the body,” Seibel said. “I sure would want it out of my body as soon as possible.”

Cameron Lee, a research engineer in electrical engineering, helped design the TCE electronics. “There has to be a tether,” he said. “Even though the camera is at the tip, you need to deliver the laser to the camera and also to detect the light coming back.”

Lee said the tether also facilitates the controlled movement of the camera. “If you have a tether, by pulling it up the camera part always looks down,” he said. “The problem with the pill is it kind of tumbles down your throat, so it’s hard to get consistent pictures out of it.”

There are plenty of factors that make the TCE unique from other endoscopes. First, it uses an entirely distinct mechanism. “It works completely differently than all other cameras; it works more like a laser printer,” Seibel said.

“A [regular] camera today has essentially an element that collects all the light [from the surface],” Lee said. “But instead of actually collecting the light from the surface, we project the light out and collect the reflection…kind of like a barcode scanner.”

The actual science behind the camera is difficult to explain. However, in simplest terms, the actual imaging is conducted through a laser light fiber scanner that moves in a spiral pattern.

“The one thing we do differently is that we scan in a spiral,” Lee said. “There are different ways of scanning, [for example] the pictures on the TV are basically scanned horizontally, left to right, kind of like how a typewriter types left to right.”

The spiral nature of the scanning resembles more of a jump rope motion. “It starts smaller in the center and spirals out bigger and bigger, collecting reflection samples across a spiral,” Lee said.

The TCE takes 250 million pixels, or 30 images, per second. “It’s not exactly a color camera, but for the most part, it’s a color image,” Lee said.

Siebel finds the colors to be “a little more vibrant, brighter and more vivid.”

The important thing is that the imaging is clear enough for the detection of the precancerous condition of esophageal cancer, called Barrett’s esophagus (BE).

The TCE makes it fairly easy to detect cancer in the esophagus by the detection of red color in the wrong places, Seibel said. The esophagus should be white, but if there are red blotches down low, it would be an indication that the patient should get a biopsy.

If detected, BE would be an irritation located “where the stomach and esophagus meet,” Lee said. “Basically, it is a step beyond acid reflex irritation. It’s noticeable because it has a red color.”

The benefit of the TCE is the ease with which it can be used.

“The idea is that you can go down there with a pill and take a look at it without having to sedate people,” Lee said.

In addition, the TCE imaging procedure is fairly harmless for the patient. “Most endoscopes are a nonsignificant risk,” Seibel said.

“It’s fairly benign for the most part,” Lee added. “I don’t really see it as a dangerous device.”

A significant roadblock for the project is distributing the TCE at a low cost. Because TCE’s are made by hand, the probes cost about 50 times more than they should, Seibel said, but if the production is automated, the probes will cost less than $100.

“I feel like the technology is fairly mature, so the roadblocks tend to be figuring out details,” Lee said. “Where can I sell it? You have to look at all the medical regulations that you have to pass. Is it safe? Is it as good as current devices? Does it have clinical significance?”

As of now, the TCE has only been tested on Seibel. The probe can be used by anyone who has the capability to swallow, and they plan to begin clinical testing in the spring at the Seattle VA Medical Center.

The researchers have received a grant from the National Institutes of Health (NIH) to make 50 TCEs. Seibel is now searching for three undergraduates who are interested in working full time for this during the upcoming summer. One would be responsible for software work, and two will actually be making the cameras.

The researchers are certain that the camera will have greater impacts in the future. Lee claims that the camera’s size is even small enough to enter the bloodstream. But typical light wavelengths will not produce clear images of the blood. “You’d have to find the correct wavelength and find a laser source that will deliver that wavelength,” Lee said.

The camera is useful for imaging anything that is small and narrow in diameter.

“People have been considering using it for imaging of fallopian tubes, or areas of the lung. We have some images of the bile duct in the pancreas,” Lee said.

Both Seibel and Lee are convinced of the TCE’s potentially useful application in developing countries. According to Seibel, the TCE could eventually be battery-powered with a laptop, just like cell phones. He said this technology is ideal for the TCE’s survival in the infrastructure of developing countries.

“[The TCE] has potential to be the device to be very cheap and nearly disposable. Endoscopes today are expensive and have to be washed,” Lee said. He proposes that if the device is cheap enough and disposable, developing countries would be able afford it.

For now, Seibel hopes to establish the TCE as a screening technique to detect precancerous esophageal cancer within the next five years. He claims that few cancer screenings (for example, a PET scan) are available for patients, especially one that can detect precancerous esophageal cancer. Seibel said the statistics of esophageal cancer shouldn’t be overlooked.

“It has small numbers now, but the rates are still high,” he said. “We are just trying to prepare for it.”

[Reach contributing writer Semonti Hossain at development@thedaily.washington.edu.]