A method to estimate the ratio of absorption coefficients of two wavelengths using phase-modulated near infrared light spectroscopy

摘要: Near infrared (MR) spectroscopy provides a very useful tool to monitor the oxygen saturation of living biological tissue non-invasively (1–3). Since has high effective scattering factor (µs’), light travels relatively long path length making it difficult compute absorption coefficient (µa) by usual methods. Phase Modulation Spectroscopy (PMS) is one method measure optical length, and estimate µ from highly media. By measuring ratio µa’s two different wavelengths, we can determine hemoglobin (Hb) within (4). A technique using modulated frequencies at wavelength been reported Sevick et al. This requires more complicated system for determining . In this report, present an improved obtaining coefficients single frequency PMS system.