New painless laser device could replace invasive x-rays

The method, called Raman Spectroscopy, could help detect breast cancer, tooth decay and osteoporosis early on. Researchers say the technique could become widely available in about five years.

Scientists believe that the technology would make the diagnosis of illnesses faster, cheaper and more accurate.

Raman spectroscopy is the measurement of the intensity and wavelength of scattered light from molecules. The process is being used in the chemical and pharmaceutical industries.

Michael Morris, a chemistry professor at the University of Michigan, US, has been using Raman for the past few years to study human bones.

"You can replace a lot of procedures, a lot of diagnostics that are out there right now. The big advantage is that it's non-invasive, pretty fast - much faster than classical procedures - and more accurate," he said.

When a person is sick, or about to become sick, the chemical mix in the tissue is quite different from that in healthy tissue, scientists say. So the Raman spectrum changes depending on the tissue it analyses, Professor Morris explained.

"Raman gives you a molecular fingerprint, a composition of whatever it is you're measuring," he said.

The diagnoses could be carried out in a matter of minutes and without need for an X-ray.

"A patient simply puts his or her wrist on a table and then we have the optical fibres delivering laser light... connected to a holder, a sort of a bracelet made out of silicon, that is strapped to the patient's wrist," Morris explained.