STUDY AND MEASUREMENT OF INFRARED SPECTROSCOPY AND ITS

APPLICATIONS IN MEDICINE

Done byTaif Alawsi

INTRODUCTION• Infrared spectroscopy deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. • It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic techniques, it can be used to identify and study chemicals. For a given sample which may be solid, liquid, or gaseous, the method or technique of infrared spectroscopy uses an instrument called an infrared spectrometer (or spectrophotometer) to produce an infrared spectrum.

•A basic IR spectrum is essentially a graph of infrared light absorbance (or transmittance) on the vertical axis vs. frequency or wavelength on the horizontal axis. • Typical units of frequency used in IR spectra are reciprocal centimeter cm−1. Units of IR wavelength are commonly given in micrometers μm, which are related to wave numbers in a reciprocal way. •A common laboratory instrument that uses this technique is a Fourier transform infrared (FTIR) spectrometer.

APPLICATIONS• The primary application of NIRS to the human body uses the fact that the transmission and absorption of NIR light in human body tissues contains information about hemoglobin concentration changes. When a specific area of the brain is activated, the localized blood volume in that area changes quickly. •Optical imaging can measure the location and activity of specific regions of the brain by continuously monitoring blood hemoglobin levels through the determination of optical absorption coefficients.

•NIRS can be used for non-invasive assessment of brain function through the intact skull in human subjects by detecting changes in blood hemoglobin concentrations associated with neural activity.

MEASUREMENTS

Typical measurement curve

FT-IR System diagram

FT-IR System device

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