MR-Controlled Capsule Endoscope Devised to Image the Digestive System

Endoscopes--small cameras or optic fibers that are typically attached to flexible tubing designed to investigate the interior of the body--can be dangerously invasive. Medical procedures frequently require sedative medications and some recovery time.

Researchers are now developing a capsule endoscope that can travel through the digestive tract to identify problems independent of any attachments.

According to Dr. Gabor Kosa of Tel Aviv University’s (TAU) School of Mechanical Engineering, the study was inspired by an endoscopic capsule designed for use in the small intestine. But unlike the existing capsule, which travels at random and snaps pictures every half second to give clinicians an overall view of the intestines, the new “wireless” capsules will use the magnetic field of a magnetic resonance imaging (MRI) scanner and electronic signals manipulated by those operating the capsule to forge a more precise and deliberate path.

It is a less invasive and more accurate way for clinicians to get an crucial look at the digestive tract, where difficult-to-diagnose tumors or wounds may be hidden, or allow for treatments such as biopsies or local drug delivery. The technology, which was reported online October 28, 2011, in the journal Biomedical Microdevices, was developed in collaboration with Dr. Peter Jakab, an engineer from the surgical planning laboratory at Brigham and Women’s Hospital (Boston, MA, USA) affiliated with Harvard Medical School (Boston, MA, USA).

What makes this endoscope unique is its ability to investigate actively the digestive tract under the direction of a physician. To achieve this, the device relies on the magnetic field of the MRI machine as a “driving force,” said Dr. Kosa. “An MRI has a very large constant magnetic field,” he explained. “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 have given them “tails,” a combination of copper coils and flexible polymer. The magnetic field generates a vibration in the tail, which allows for movement, and 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 difficulties posed by MRI, Dr. Kosa added. Whereas most magnets interfere with MRI by obscuring the image, copper appears as only a minor spot on otherwise clear film.

The ability to drive the capsule, according to Dr. Kosa, will not only lead to better diagnosis capabilities, but patients will experience a less invasive procedure in a fraction of the time.

In the lab at the Brigham and Women’s Hospital, Dr. Kosa and his fellow researchers have assessed the driving mechanism of the capsule in an aquarium inside the MRI. The results have shown that the capsule can effectively be operated using a magnetic field. In the next step, the researchers are hoping to additional develop the capsule’s endoscopic and signaling functions.

According to Dr. Kosa, a new faculty recruit to TAU, this project is part of a bright future for the field of microrobotics. At the university, his new research lab, called RBM2S, focuses on microsystems and robotics for biomedical applications and an educational engineering robotics lab (ERL) will teach future robotics experts studying at TAU’s School of Mechanical Engineering.

Related Links:
Tel Aviv University
Brigham and Women’s Hospital