Optical Transmission through Whole Blood Illuminated with Highly Collimated Light*

Abstract

The fundamental parameters necessary for describing the optical behavior of nonhemolyzed blood by means of diffusion equations for photons are presented. The methods and results of experimental work to determine the single-scattering parameters for dilute milk and nonhemolyzed blood are explained. The single-scattering properties of nonhemolyzed blood can significantly increase the diffculty of obtaining those optical absorption characteristics necessary for the determination of the relative O₂ saturation of the hemoglobin. A diffusion theory for photons was applied to the system used to measure transmittance of dilute milk and nonhemolyzed blood samples. The agreement between the experimental and theoretical results is good, especially considering the wide range of transmittance over which the results extend. The significance of the results to problems in oximetry is stated.