Magnetic pill camera can be steered and stopped in body

18 June 2008

Taking pictures inside the body using a small camera swallowed by the patient is not new, but in the past there was no way of controlling the device as it passed through the body. A new pill camera (see picture on right) developed by an international team of researchers can be steered and stopped where desired, and even deliver images of the oesophagus.

Images of the inside of the intestine can be obtained with a small 'pill' camera that the patient swallows. It makes its way through the intestine and transmits images of the intestinal villi to an external receiver which the patient carries on a belt.

This device stores the data so that the physician can later analyze it and identify any haemorrhages or cysts. However, the camera is not very suitable for examinations of the oesophagus and the stomach. The reason is that camera only takes about three or four seconds to make its way through the oesophagus — producing two to four images per second — and once it reaches the stomach, its roughly five-gram weight causes it to drop very quickly to the lower wall of the stomach. In other words, it is too fast to deliver usable images.

For examinations of the esophagus and the stomach, therefore, patients still have to swallow a rather thick endoscope.

In collaboration with engineers from the manufacturer Given Imaging, the Israelite Hospital in Hamburg and the Royal Imperial College in London, researchers from the Fraunhofer Institute for Biomedical Engineering in Sankt Ingbert have developed the first-ever control system for the pill camera.

“In future, doctors will be able to stop the camera in the eosophagus, move it up and down and turn it, and thus adjust the angle of the camera as required,” says IBMT team leader Dr. Frank Volke.

“This allows them to make a precise examination of the junction between the oesophagus and the stomach, for if the cardiac sphincter is not functioning properly, gastric acid comes up the oesophagus and causes heartburn. In the long term, this may even cause cancer of the oesophagus. Now, with the camera, we can even scan the stomach walls.

“We have developed a magnetic device roughly the size of a bar of chocolate. 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,” says Volke.

The steerable camera pill is constructed in much the same way as its predecessor: It consists of a camera, a transmitter that sends the images to the receiver, a battery and several cold-light diodes which briefly flare up like a flashlight every time a picture is taken. One prototype of the camera pill has already passed its first practical test in the human body. The researchers demonstrated in a self-experiment that the camera can be kept in the oesophagus for about ten minutes, even if the patient is sitting upright.