Patent ID: 7532919
Filing Date: 2009-05-12
Classification: A61B,G01N

Abstract:
1. A method for calculating oxygen saturation in a target tissue, the method comprising: directing incident radiation from a source to a target tissue and determining reflectance spectra of the target tissue with a detector by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and outputting the determined value of oxygen saturation, wherein determining reflectance spectra of the target tissue comprises: measuring, at a first source-detector spacing, a first reflectance spectrum from the target tissue that comprises a first weighting of contributions from the target tissue and from the skin and fat layers, and measuring, at a second source-detector spacing different from the first source-detector spacing, a second reflectance spectrum from the target tissue that comprises a second weighting of contributions from the target tissue and from the skin and fat layers different from the first weighting; and wherein correcting the measured intensities of the reflectance spectra comprises: correcting the measured intensities of the first reflectance spectrum based on the measured intensities of the second reflectance spectrum.