Using Raman spectroscopy, researchers have developed a kind of biopsy tool that could be used to spot diseased tissues in seconds, according to a new report in the Journal of Photochemistry and Photobiology.
In today's healthcare system, most diseases are identified in patients through MRIs, PETs, X-rays or CAT scans. However, all of these medical imaging techniques are associated with some type of radiation risk. Furthermore, many of these processes take hours or days to produce useful outcomes. Above all, the degree of data they supply is lacking, since it is not at the molecular level.
Commonly used in chemistry to identify molecular structures, Raman spectroscopy uses laser light to identify rotational, vibrational and other low-frequency actions of a molecular system. The technique is slowly being adopted by the medical and biomedicine communities to produce optical biopsies that provide more comprehensive, faster detection of disease. This unique, less intrusive strategy for detecting disease was first used in 1991 to recognize a biomarker for cancer.
The new paper represents how medical research using Raman spectroscopy continues to advance. Specifically, the paper describes how Resonance Raman spectroscopy investigating carotene in tissues using several visible lasers can recognize signature vibrations when a laser enters an absorption of a molecule.
In the study, the researchers said they used four different laser beams to generate Raman spectra: 488 nanometres, 514 nanometres, 532 nanometres and 633 nanometres. The researchers ultimately determined the 532 nanometer (nm) laser is the ideal choice.
“Resonant Raman using the laser pointer 532 nm has become an eﬃcient tool for investigating molecular components in tissues and cells, providing more detailed information and a way to detect diseases like skin cancer, brain cancer, or atherosclerosis – in mere seconds,” study author Robert Alfano, director of The Institute for Ultrafast Spectroscopy and Lasers (IUSL) of the City University of New York at City College, said in a news release.
The new paper comes after a June 2017 report described how researchers were able to use three different kinds of spectroscopy to spot cancerous tissues in real time during surgery.
Published in the journal Cancer Research, the paper described a cancer detection system that combined diffuse reﬂectance spectroscopy, intrinsic ﬂuorescence spectroscopy and Raman spectroscopy. The novel system was able to detect colon, lung and skin cancer during surgery with 97 percent accuracy, 100 percent sensitivity and 93 percent specificity.
To reach their conclusion, researchers evaluated the optical system in 15 individuals with cancer, who were having open cranium surgery at the Montreal Neurological Institute and Hospital. The study team inspected 10 to15 locations in each patient (161 locations overall) and took optical readings of tissues at each location to ascertain if cancer cells were present.
Since the report was published in June, the study team – from the Montreal Neurological Institute and Hospital and McGill University in Montreal – has taken their system to clinical trials and sought regulatory approval in the United States.
"We have tested it in brain, lung, breast, colon, skin, and prostate cancers," study author Kevin Petrecca, chair in neuro-oncology at Montreal Neurological Institute, said in a news release. "It is highly accurate in these types — we have not yet tested it in other types — but it can be used to detect cancer in at least all of those types."
“Raman spectroscopy (RS) alone can achieve 90 percent detection accuracy, but by combining RS with intrinsic fluorescence spectroscopy and diffuse reflectance spectroscopy, we are excited that our results showed 97 percent accuracy, 100 percent sensitivity, and 93 percent specificity,” added co-author Frédéric Leblond, a researcher at the University of Montreal Hospital Research Centre, who developed the tool together with Petrecca.