Researchers at Massachusetts General Hospital’s Wellman Center for Photomedicine have used coherent anti-Stokes Raman Scatterings (CARS) microscopy to improve detection of melanoma, the most common skin cancer.

Led by Conor Evans, a professor in Harvard University’s Wellman Center for Photomedicine, the team was able to improve detection of pheomelanin, a light-colored pigment in melanomas, using CARS microscopy, a chemically-specific version of Raman imaging that detects molecular vibrations.  

“We started to look through the Raman literature,” said Evans. “Raman spectroscopy is a very mature technique that allows you to detect molecules by their unique chemical vibrations, which are themselves derived from the structure of the molecules. CARS microscopy is a coherent Raman tool that is akin to using a tuning fork to specifically detect molecular structures.”

Scientists often assume pheomelanin is invisible, because no reliable method of detection currently exists.

“Pheomelanin has a unique chemical structure, there is nothing else like it in the body,” said Evans. “So, we started to look at the molecular structure and noticed there was a corresponding unique molecular vibration that might be useful for imaging the pigment with CARS microscopy.”

This initial exploration of the advanced imaging method showed promise, leaving the team hopeful that it will impact future research on pheomelanin detection and, in general, efforts to combat melanoma.

Sam Osseiran, one of the scientists involved in the research, will present the team’s findings at the Optical Society Biophotonics Congress in April in San Diego.