us scientists have produced a device that could potentially screen patients for lung cancer.

The new device works from a known principal: lung cancer cells give off different chemicals known as volatile organic compounds (vocs), that healthy cells don't.

Earlier experiments had established that dogs with their heightened sense of smell could distinguish the breath of a cancer sufferer from a healthy individual. Scientists have also used sophisticated equipment such as mass spectrometers to detect the chemicals in patient's breath.

Now, researchers from the Cleveland Clinic in the us have developed a colour sensor that could screen patients. The research reported online in Thorax, an International Journal of Respiratory Medicine, tested the accuracy of the inexpensive device, roughly the size of a two rupee coin.

The apparatus has a series of 36 colours which change hue depending on the chemicals they come into contact with. Scientists are able to analyse these hues for a diagnosis. They found that the mechanism accurately diagnosed cancer in around 75 per cent of cases. This may prove an invaluable tool in the battle against lung cancer when ready, Mazzone, the lead author of the paper said.