Absolute Quantifications of Oxy- and Deoxyhemoglobin Concentrations by Combination of Differentially Resolved Spectroscopy and Spatially Resolved Spectroscopy

This letter proposes a theoretical framework to calculate absolute concentrations of oxy- and deoxyhemoglobin using continuous-wave near-infrared spectroscopy. While previous methods on this topic require assumptions on constant blood volume, the proposed method does not. Equations for the absolute concentrations were derived from a combination of the modified Beer–Lambert equation and the theory of diffusion of photons in turbid media. The method has an advantage over and is theoretically consistent with previous methods. It needs yet to be evaluated in an experimental study.