Capsule endoscope forges precise path through the body

Ashley N. Paddock, ashley.paddock@photonics.com

It’s something straight out of “Fantastic Voyage”: Minute capsules could someday travel through the body, taking pictures and delivering drugs more effectively and less invasively than current bulky endoscopes. Guiding them? Simple magnetism.

In a method developed by Gabor Kosa at Tel Aviv University, magnetic waves generated by an MRI device guide the capsules on a more precise course through the small intestine to detect hard-to-diagnose tumors and wounds. Being able to manipulate the capsule will bring about better diagnostic capabilities as well as faster, less invasive procedures, Kosa said.

Current endoscopes generally are attached to flexible tubing pushed into and through the body, but this can be invasive and even dangerous; these procedures often require sedation and some recovery time. Kosa’s capsule endoscope can travel the digestive tract to explore issues without any wires or attachments.

The project was inspired by an endoscopic capsule used in the small intestine: The existing capsule travels at random and snaps pictures every half-second to give doctors an overall view of the intestines, but the new capsules can be steered “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, Kosa and colleagues gave them “tails,” a combination of copper coils and a flexible polymer. The magnetic field makes the tail vibrate, 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.

Because copper is nonferromagnetic, it circumvents other diagnostic challenges posed by MRI, Kosa noted – most metals interfere with MRI by obscuring the picture, but copper shows 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, the team test-drove the capsule’s steering mechanism by putting an aquarium inside the MRI. The results showed that the capsule can successfully be manipulated using a magnetic field.