The new 256-slice CT machine takes large numbers of X-ray pictures, and combines them using computer technology to produce the final detailed images.

It also generates images in a fraction of the time of other scanners: a full body scan takes less than a minute.

The Philips machine was unveiled at the Radiological Society of North America.

Because the images are 3D they can be rotated and viewed from different directions - giving doctors the greatest possible help in looking for signs of abnormalities or disease.

All images also can be accessed on any computer in a hospital or by colleagues and researchers remotely, to make it easier for the whole team to share information.

The scan is much quicker than current technology, as the machine's X-ray emitting gantry - the giant ring-shaped part that surrounds the patient - can rotate four times in a single second - 22% faster than current systems.

The cost of the equipment - known as the Brilliance CT - is unclear.

At present, it is only being used in one hospital: the Metro Health medical centre in Cleveland, Ohio, which has been using it for the past month.

"This scanner allows radiologists to produce high quality images and is also designed to reduce patients' exposure to X-rays," Steve Rusckowski, chief executive of Philips Medical Systems, said.

"It is so powerful it can capture an image of the entire heart in just two beats."

The record company EMI was behind the first commercially viable CT scanner, which was invented by Sir Godfrey Newbold Hounsfield in Hayes, United Kingdom at the company's laboratories and unveiled in 1972.

At the same time, Allan McLeod Cormack of Tufts University independently invented a similar machine, and the two men shared the 1979 Nobel Prize in Medicine.

"This is a quantum shift from the first CT scanners as it gives a lot more detail," says Dr Keith Prowse, Chairman of the British Lung Foundation.

"It seems to be another step beyond what we were previously able to do. The high resolution enables you to see smaller things in both the lungs and the airways and then decide whether there is anything there and how best to get at it.