A pioneering technique developed by scientists could help doctors detect respiratory diseases like asthma or cancer with a laser light.
A team at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado (CU) at Boulder have developed a technique called cavity-enhanced direct optical frequency comb spectroscopy that can detect molecules in the breath that may be indicators for diseases.
'This technique can give a broad picture of many different molecules in the breath all at once,' said Jun Ye, lead researcher.
While breathing we inhale a complex mixture of gasses including nitrogen, oxygen, carbon dioxide, and water vapour and also some traces of carbon monoxide, nitrous oxide, and methane that are potential biomarkers of disease.
The team led by Jun Ye, fellow of JILA, a fellow of NIST and a professor adjoint at CU-Boulder's Department of Physics analysed the breath of several student volunteers with the help of optical frequency comb spectroscopy.
They showed that they could detect traces of gasses like ammonia, carbon monoxide, and methane on their breath and also detected carbon monoxide in a student smoker that was five times higher.
The students had to breathe into an optical cavity, a space between two standing mirrors. The optical cavity was designed so that when they aimed a pulsed laser light into it, the light bounced back and forth so many times that it covered a distance of several kilometers by the time it exited the cavity.
This essentially allowed the light to sample the entire volume of the cavity, striking all the molecules therein.
They compared the light coming in and going out of the cavity and detected the molecules present in the breath from the start.
Scientists believe that while the technique is yet to be evaluated in clinical trials, monitoring the breath for such biomarkers is an attractive approach to medicine because breath analysis is the ultimate non-invasive and low-cost procedure.
The findings are published in the latest issue of the Optical Society of America's open-access journal Optics Express.