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3 Medical Applications of NIR Spectroscopy

  • Health
NIR Spectroscopy

Astronomers use light to learn about stars. Chemists use it to analyze materials. Doctors diagnose with it: learn 3 medical applications of NIR spectroscopy.

Living things and inanimate objects can absorb and reflect visible and invisible light. The kind of light they absorb or reflect provides information about what cells or substances are present in a given sample.

What Is NIR?

Light travels in waves of different lengths, the distance from the peak of one wave to the next. When that distance is tiny, the light is at the “blue” end of the electromagnetic spectrum. Long waves are on the “red” side.

Humans can see only a tiny portion of the spectrum, from 0.4 to 0.7 micrometers. Near-infrared spectroscopy studies light reflected in the spectrum just beyond the visible, from about 0.7 micrometers to 0.1 millimeters.

Reflected light typically occurs in the near-infrared (NIR) region, from 0.7 to 3.0 micrometers. The infrared is measured as heat or thermal radiation above that wavelength.

Doctors and medical researchers choose NIR spectrometersto analyze the wavelengths of light reflected from human tissue to determine whether disease or toxins are present.


Cancerous tumors behave differently than normal cells, with variations in blood flow and oxygenation. An NIR spectrometer can detect these variations, helping doctors understand the location and size of tumors and the effectiveness (or lack thereof) of treatments in shrinking tumors.


Like its use in cancer detection, NIR spectroscopy can detect abnormalities in brain function by measuring oxygenation. Blood carries essential oxygen to the brain, so brain damage occurs when the brain doesn’t receive adequate blood flow.

Neurologists can non-invasively measure brain oxygenation using NIR spectroscopy to identify areas of the brain that don’t function as they should. They can also determine whether the brain is recovering properly from surgery or injury.

Functional NIR spectroscopy can “see” brain activity in real time because blood flow increases when areas of the brain activate.

Pediatric Cardiology

Parents and doctors prefer to avoid invasive procedures on infants as much as possible. Portable NIR spectrometers can non-invasively measure cardiac output in infants following surgery. It’s painless and doesn’t involve the radiation of an X-ray procedure.

These are just three medical applications of NIR spectroscopy. It’s also useful in urology, rehabilitation, and ergonomics. Researchers are developing non-invasive ways to measure blood glucose with NIR spectroscopy, which would mean diabetic people would no longer have to endure finger-pricks to monitor their blood sugar.

Spectroscopy can provide fascinating information about the most distant stars, and NIR spectrometers can give us minute details about blood and oxygen flow to the cells within our bodies.