Just over a decade ago, near-infrared (NIR) spectroscopy was referred to as the "sleeper among spectroscopic techniques"[wetzel 1983], but today it has already become a powerful anaytical tool with growing number of applications in agriculture, pharmaceutical and petrochemical industries. The main reason behind the popularity of NIR spectroscopy is its ability to determine the chemical composition of complex solids and liquids with relatively low-cost and easy-to-use instrumentation. The availability of devices for measuring chemical compounds in intact biological tissues would open a new dimension in clinical medicine. Progress towards this goal has been slowed, however, by the challenge of extracting reliable data from an optical media as complex as biological tissue....[ Read more ]

Just over a decade ago, near-infrared (NIR) spectroscopy was referred to as the "sleeper among spectroscopic techniques"[wetzel 1983], but today it has already become a powerful anaytical tool with growing number of applications in agriculture, pharmaceutical and petrochemical industries. The main reason behind the popularity of NIR spectroscopy is its ability to determine the chemical composition of complex solids and liquids with relatively low-cost and easy-to-use instrumentation. The availability of devices for measuring chemical compounds in intact biological tissues would open a new dimension in clinical medicine. Progress towards this goal has been slowed, however, by the challenge of extracting reliable data from an optical media as complex as biological tissue.

In this research, we propose a non-invasive method for determination of absolute value of the hemoglobin content of arterial blood and water content of skin using diffuse reflectance spectrophotometry in the near-infrared band (800 - 1600 nm). We examine methods for relating the microstructure of a tissue to the magnitude and wavelength dependence of its scattering coefficient and derive a modified photon diffusion model. As an alternative to the conventional method based on experimental calibration, we use theoretical model to simulate the reflectance spectra from which a calibration model is derived. The algorithm is verified with tissue- mimicking phantoms and the experimental results suggest that our approach can be used for assessment of acute anemia and dehydration.