Capsule Endoscope Forges Precise Path Through the Body

Tiny capsules guided by magnetic steering are set to do the work of bulkier endoscopes, perhaps leading one day to less invasive, yet more powerful, imaging and drug delivery inside the body.

At Tel Aviv University, Gabor Kosa devised a method to guide endoscopic “capsules” on a more precise course through the small intestine to detect difficult-to-diagnose tumors and wounds. The capsules are guided through the body via the magnetic waves generated by a magnetic resonance imaging (MRI) instrument. The ability to manipulate the capsule, Kosa said, will lead to better diagnostic capabilities as well as a faster, less invasive procedure.

An endoscopic capsule being tested at Brigham and Women’s Hospital can be steered through the body using magnetic waves from an MRI machine. (Photo: American Friends of Tel Aviv University)

Endoscopes usually are attached to flexible tubing that is pushed through the interior of the body, but this can be dangerously invasive. Procedures often require sedatives and some recovery time. The capsule endoscope developed by Kosa can move through the digestive tract to detect problems independent of any attachments.

The project is inspired by an endoscopic capsule designed for use in the small intestine. Unlike the existing capsule, which travels at random and snaps pictures every half second to give doctors an overall view of the intestines, the Tel Aviv University capsules use the MRI’s magnetic waves to forge a more precise and deliberate path.

“An MRI has a very large constant magnetic field,” Kosa said. “The capsule needs to navigate according to this field, like a sailboat sailing with the wind.”

To help the capsules “swim” with the magnetic current, the researchers gave them “tails,” a combination of copper coils and a flexible polymer. The magnetic field creates a vibration in the tail, which allows for movement. Electronics and microsensors embedded in the capsule allow the capsule’s operator to manipulate the magnetic field that guides the movement of the device. The use of copper, a nonferromagnetic material, circumvents other diagnostic challenges posed by MRI, Kosa said. While most magnets interfere with MRI by obscuring the picture, copper appears as only a minor blot on otherwise clear film.

The technology, which was recently reported in Biomedical Microdevices, was developed in collaboration with Peter Jakab, an engineer from the Surgical Planning Laboratory at Brigham and Women’s Hospital in Boston.

In the lab at Brigham and Women’s, Kosa and his colleagues tested the driving mechanism of the capsule in an aquarium inside the MRI. The results showed that the capsule can successfully be manipulated using a magnetic field. Moving forward, the researchers are hoping to further develop the capsule’s endoscopic and signaling functions.

For more information, visit: www.aftau.org