By Kate Baggott

Researchers in Germany have developed a magnetic device that can guide a camera inside the body. The remote control will enable doctors to conduct internal examinations of the stomach and esophagus, procedures that are currently done with an endoscope and are often uncomfortable, requiring local anesthetic and several hours of recovery time.

Some of these discomforts may be avoided with the controllable pill camera, says Frank Volke, head of the research team at the Fraunhofer Institute for Biomedical Engineering, in Sankt Ingbert, Germany, who developed the technology. "The doctor can hold it in his hand during the examination and move it up and down the patient's body. The camera inside follows this motion precisely."

Roughly the same size as a multivitamin tablet, pill cameras, also known as capsule cameras, have been used for about five years. Once swallowed, the camera travels through the patient by taking advantage of peristalsis, the same involuntary muscular contractions that push food through the digestive system. During the process, the cameras transmit two to four images per second to a receiver worn on the patient's belt.

While highly effective for taking pictures of the intestines and colon, current models of the camera-in-a-pill haven't been as effective in the esophagus and stomach. Typically, the five-gram, nondigestible cameras take just a few seconds to travel through the esophagus and then fall quickly to the lower wall of the stomach.

"The greatest limitation of the current generation of capsule systems is the inability to control the device," says Mark Schattner, a gastroenterologist with a special interest in therapeutic endoscopy at Memorial Sloan Kettering Cancer Center, in New York. He believes that a control, like that developed by Volke's team, could reduce those limitations. "A system that allows accurate and real-time directional control of the capsule using an external magnetic field is a significant advance," he says.

The Fraunhofer controller, developed in cooperation with the Israeli PillCam manufacturer Given Imaging, addresses the issue by directing the camera's movements in the body.

The controllable camera pill, like its predecessor, contains a camera, a transmitter, a battery, and cold-light diodes that flare up like a camera flash when an image is captured. The key addition is the magnetic controller that allows the examiner to control the position and the angle of the camera from outside the body.

"The control field and movement are produced completely and without contact outside the body," says Volke. "Changing the intensity of the magnetic field at a distance, changes the position of the camera."

While earlier experiments conducted by the research team and its partners have had success controlling capsule cameras in pigs, this is the first external controller to have success in a human experiment.

Volke's team demonstrated the control mechanism during a single self-experiment. When using the magnetic controller, the camera could be kept in the esophagus for about 10 minutes while the subject sat upright.

"This first tester did not report any unpleasant effects," says Volke. "Doctors will be able to stop the camera in the esophagus, move it up and down and turn it, and adjust the angle of the camera as required. This allows them to make a precise examination of the junction between the esophagus and the stomach."

David Fleischer, a gastroenterologist with the Mayo Clinic in Arizona, agrees that the development of the magnetic controller is significant. He believes that capsule-based technologies will soon be able to deliver therapeutic treatments in addition to diagnostic tests. "The development of a mechanism to control movement will be the next important step to allow the capsule to be moved into specific areas," says Fleischer. "This will pave the way for biopsies to be taken and treatments to be delivered."