Raman Micro-Spectroscopy Measurement Of Hemoglobin Oxygen Saturation Using 532 Nm Excitation

The usefulness of the 532 nm laser excitation to estimate hemoglobin oxygen saturation (SO2) based on Raman spectra was investigated. Noninvasive microscopy and Raman spectroscopy were used to determine SO2 in vitro and in vivo. Up to six peaks could be used to estimate SO 2 by Raman spectroscopy, corresponding to three oxidation state marker bands of hemoglobin (Hb), designated as n4, n10 and n19. The estimated SO2 using Raman correlated well with SO2 measured via co-oximetry, allowing SO2 to be determined in the physiological range. The system was successfully used to determine local SO2 of rats and mice.