LONDON, MAY 26: Real life meets science fiction yet again with the invention of the first pill-size capsule camera that on being swallowed records what it sees on a fantastic voyage through a person's digestive system. In sci-fi writer Isaac Asimov's classic story, Fantastic Voyage, a submarine and its crew are shrunk and injected into the bloodstream of a man who has been shot. Their mission is to travel through his arteries to destroy a blood clot in his brain before it kills him.The real-life capsule camera is the work of Gavriel Iddan, an Israeli inventor, and Prof Paul Swain, a gastroenterologist from the Royal London Hospital. It measures 11 mm by 30 mm and contains a tiny video camera, light source and transmitter. The capsule radios images to a portable recorder strapped to the patient's waist. Both Prof Swain and Iddan have swallowed their curious capsule to observe the rumblings of their gut.The capsule is forced through the intestinal tract just as food is by natural contractions and eventually expelled. It takes 24 hours for the capsule to travel in and out of a person's digestive tract, during which time the camera provides up to six hours of high-quality images from the stomach, small bowel and mouth of the large intestine.The advantage of the ``capsule endoscope'', according to its inventors, is the ease and painlessness with which does its job. Iddan says: ``It is very smooth. You swallow it and you don't feel anything. A sip of water and it is down.'' A normal endoscopy needs hospitalisation and is physically uncomfortable, requiring a bundle of fibre optic cables to be inserted up the patient's rectum or down the throat. Prof Swain says: ``Once they have swallowed the pill, they don't feel it - and they can go home or go to work. The belt and the receiver is then sent to the hospital where it is plugged into a computer. A doctor can then examine the images to see if there are any problems.''Prof Swain explains one of the big advantages of the capsule endoscope is that it can be used to take images in the small bowel, a part not so easily accessible with conventional endoscopes inserted through the rectum. ``I've seen my small bowel and smiled. Not many people can say they've done that because it is usually quite painful in that area,'' he says.According to the journal, Nature, the capsule has been tested on 10 volunteers but it must complete clinical trials before it is available commercially. Prof Swain is awaiting approval from the regulatory authorities in Britain but says he hopes to begin clinical trials this year.The scientists, who include electronic engineers from Given Imaging Ltd in Israel, are working on refining the capsule so that it can become a ``core device'' in diagnostic medicine. Unlike normal endoscopy, the capsule cannot remove tissue samples for biopsies, or polyps or small tumours. Keeping Asimov's fantasy alive, Prof Swain says: ``Maybe we could make it move around like a little robot and travel up and down the gut. Maybe we could make it sample tissues or send out signals that imply what is going on inside the body - and, perhaps, in the future we could even treat people from the inside.''
