To see inside the digestive system, doctors have to thread a scope up or down - potentially doing damage along the way - or get their patients to swallow a capsule that tumbles through, uncontrolled, snapping random pictures.
Researchers at Brigham and Women’s Hospital are now developing a “swimming capsule’’ that they hope will combine the best of both approaches: the control of the endoscope with the safety and ease of a pill.
The team of scientists, led by Nobuhiko Hata, associate professor of radiology, still has a lot of work to do before the plastic capsule could be ready for use in a patient. But several scientists not involved in the work praised their concept and the advances they have made as “an amazing accomplishment.’’
“This technology addresses a significant shortcoming of capsule endoscopy,’’ said Adam Wax, a Duke University professor who has been developing advanced fiber endoscopes.
Wax said he imagines a lot more people would be willing to undergo colonoscopies if they could simply swallow a capsule, rather than have the current scoping procedure, which involves unpleasant preparation as well as risk of bowel damage. Today’s capsule endoscopes - tiny cameras encased in plastic - can’t be used for cancer screening, he said, because they take pictures at random intervals and so only catch cancers by chance or if the tumor is extremely large.
The images can be seen only later, once the capsule has sent them wirelessly to a data recorder worn on the patient’s belt, so a second procedure is often needed to confirm a diagnosis. Capsule endoscopes are naturally excreted and painless.
Hata wants his capsule to deliver images in real time, allowing doctors to identify and explore areas of concern with one procedure. He would also like the capsule to be able to ferry drugs to the tumor or injury site, or deliver laser pulses, zapping a tumor from within the bowel - though he admits this idea is farfetched, based on existing technology.
For now, he and the team are working to improve the steering and powering of their capsule. In a paper published in October in the journal Biomedical Microdevices, they showed they could “swim’’ their capsule through a tank of water, powered by a conventional MRI machine.
The magnetic field of the MRI rotates several tiny wire coils in the capsule. The current that runs through them sequentially creates a tail motion, like a swimming sperm, allowing the capsule to propel itself through liquid.
“The idea is fantastic to use a magnetic field to steer the capsule through the small bowel,’’ said Dr. Kai Matthes, director of the Developmental Endoscopy Lab at Beth Israel Deaconess Medical Center. He said he sees potential for the capsule to identify tumors, malformations, and bleeding problems within the small intestines.
Right now, doctors can reach 40 to 80 percent of the small bowel by threading a conventional endoscope; Hata’s swimming endoscope could potentially access the entire length of the bowel. Like current capsule endoscopes, his capsule could get trapped in a blocked or narrowed bowel, requiring surgery - though its maneuverability could help avoid that scenario.
Matthes said he can see drawbacks, too, mainly the cost of keeping a patient in an MRI machine for two to three hours while the capsule journeys through the intestines. MRI scanners typically cost $500 to $1,000 an hour and are not often available to patients with digestive problems.
“But still, I think it’s an amazing accomplishment and a step in the right direction,’’ Matthes said.
Hata acknowledges his team, which includes engineering consultant Peter Jakab and researchers at Tel Aviv University, has many issues to resolve before the capsule is ready to swim through anyone’s digestive system. It has been funded with $200,000 in grants from the nonprofit Center for Integration of Medicine and Innovative Technology, and Hata would like to find a commercial partner to help work through the remaining technical issues.
The next big step will be to figure out how to miniaturize the device, which is currently about the size of a small lipstick tube - too large to be swallowed. It will also have to be tested in animals before it can be used in people. And the team will have to figure out how to propel the capsule through the contents of the digestive system, which is obviously far different than the plain water they have used so far.
Though there are many issues to resolve, Hata has to dream, he said.
“Many scientists in my research field got into it by watching ‘Fantastic Voyage’ or its animated version,’’ he wrote in an e-mail. “Perhaps, deep in my mind, I may be taking this project as the ultimate realization of a dream to realize the submarine in the show and send it into a body to attack disease.’’