INFRARED light can help spot cancerous tissue in an instant.

To look for cancer in a biopsy, the sample is stained to highlight DNA and a protein in cytoplasm. Cancer cells contain a higher ratio of DNA to protein and a larger nucleus, making it possible to judge whether cancer is present.

To make things more objective, Chris Phillips and his colleagues at Imperial College London used light. The chemical bonds in each molecule absorb infrared light of a characteristic wavelength. By measuring the level of absorption, the amount of DNA and protein in a sample can be calculated.

The team used the method to measure levels of the two types of molecule, then generated an image to highlight areas with a cancer-like ratio (Optics Express, DOI: 10.1364/oe.20.007290).

“You put in the tissue and you can get an image in 10 to 20 seconds,” says Phillips.