Measuring tissue oxygenation
First Claim
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.
3 Assignments
0 Petitions
Accused Products
Abstract
Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.
-
Citations
37 Claims
-
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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
-
25. A method of monitoring blood volume in a patient, the method comprising:
-
directing incident radiation from a source to a target tissue of the patient 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 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 total heme concentration in the target tissue based on the corrected reflectance spectra; assessing a blood volume in the patient based on the total heme concentration; and outputting the assessed blood volume, 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. - View Dependent Claims (26)
-
-
27. 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; determining light attenuation spectra of the target tissue from the reflectance spectra, and fitting the light attenuation spectra to a model light attenuation equation; determining oxygen saturation in the target tissue based on the fitting of the light attenuation spectra; and outputting the determined value of oxygen saturation, wherein fitting the light attenuation spectra to a model comprises performing a two-stage fitting procedure wherein, in a first stage, initial values of one or more model parameters are determined, and in a second stage, the light attenuation spectra are fitted to the model, wherein the model comprises the initial parameter values determined in the first stage; and 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 skin and fat layers through which the incident radiation passes, 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 correcting the measured intensities of the first reflectance spectrum based on the measured intensities of the second reflectance spectrum. - View Dependent Claims (28)
-
-
29. A system, comprising:
-
a light source configured to direct incident radiation to a target tissue; a detector; and a processor coupled to the detector and configured to; determine reflectance spectra of the target tissue; correct the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; and determine oxygen saturation in the target tissue based on the corrected reflectance spectra, wherein the processor is configured to determine the reflectance spectra by; 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 skin and fat layers through which the incident radiation passes, 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 the processor is configured to correct the reflectance spectra by; correcting the measured intensities of the first reflectance spectrum based on the measured intensities of the second reflectance spectrum. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37)
-
Specification