INSTRUMENT FOR MEASURING CARBON MONOXIDE POISONING OF HUMANS USING IN VIVO NIRS TECHNOLOGY
First Claim
1. A method for non-invasively determining the relative amounts of a plurality of chromophores in the blood of a human or animal subject, the method comprising the steps of:
- imparting non-continuously a wavelength range of light comprising visible and near-infrared components extending down to at least about 450 nm to a light delivery fiberoptic;
passing the wavelength range of light through a selected tissue sample of the nasal septum of the human or animal subject and receiving a spectral absorption portion of the wavelength range of light in a light collecting fiberoptic;
providing a spectrometer for receiving the spectral absorption portion of the wavelength range of light from the light collecting fiberoptic;
acquiring a first spectrum of the spectral absorption portion of the wavelength range of light;
acquiring a second spectrum of ambient light at a first predetermined time interval from the acquisition of the first spectrum;
acquiring a third reference spectrum of light from the wavelength range of light at a second predetermined time interval from the acquisition of the second spectrum; and
acquiring a fourth spectrum of ambient light at a third predetermined time interval from the acquisition of the reference spectrum;
subtracting an average of the second and fourth ambient light spectrum from each of the first and third spectrum to determine a total absorption spectra of the selected tissue sample for a plurality of wavelengths selected from the wavelength range of light; and
recording light intensity at each and substantially every wavelength in the spectral range of the spectrometer for each of the plurality of wavelengths;
performing decomposition of the total absorption spectra by comparing light intensity at a first wavelength to light intensity at adjacent wavelengths to determine the concentration of the plurality of chromophores;
assembling a catalog of chromophore spectra from the recorded light intensity at each wavelength in the spectral range of the spectrometer for each of the plurality of chromophores separately by measuring each wavelength individually at the determined concentration and recorded wavelength to evaluate the spectral shape to determine the spectral signature for the chromophore;
deconvolving the total absorption spectra to determine a relative contribution of each of the plurality of chromophores in the blood of a human or animal subject; and
identifying at least one chromophore and its concentration in the blood of the human or animal subject from the catalog of chromophore spectra.
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Abstract
Spectral absorption based non-invasive procedure for determination of blood constituents utilizing in vivo NIRS (Near-Infrared Spectrum) technology, which is the measurement of the near-infrared absorption spectrum within a region of the living human body for the purpose of identifying tissue and blood components and their concentrations and more particularly to novel applications and methodology for determining the optical response, measurements and calculations relating to the concentrations of individual chromophores in the bloodstream and particularly to the level of CO chromophores in the tissues of an animal or human being.
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Citations
16 Claims
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1. A method for non-invasively determining the relative amounts of a plurality of chromophores in the blood of a human or animal subject, the method comprising the steps of:
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imparting non-continuously a wavelength range of light comprising visible and near-infrared components extending down to at least about 450 nm to a light delivery fiberoptic; passing the wavelength range of light through a selected tissue sample of the nasal septum of the human or animal subject and receiving a spectral absorption portion of the wavelength range of light in a light collecting fiberoptic; providing a spectrometer for receiving the spectral absorption portion of the wavelength range of light from the light collecting fiberoptic; acquiring a first spectrum of the spectral absorption portion of the wavelength range of light; acquiring a second spectrum of ambient light at a first predetermined time interval from the acquisition of the first spectrum; acquiring a third reference spectrum of light from the wavelength range of light at a second predetermined time interval from the acquisition of the second spectrum; and acquiring a fourth spectrum of ambient light at a third predetermined time interval from the acquisition of the reference spectrum; subtracting an average of the second and fourth ambient light spectrum from each of the first and third spectrum to determine a total absorption spectra of the selected tissue sample for a plurality of wavelengths selected from the wavelength range of light; and recording light intensity at each and substantially every wavelength in the spectral range of the spectrometer for each of the plurality of wavelengths; performing decomposition of the total absorption spectra by comparing light intensity at a first wavelength to light intensity at adjacent wavelengths to determine the concentration of the plurality of chromophores; assembling a catalog of chromophore spectra from the recorded light intensity at each wavelength in the spectral range of the spectrometer for each of the plurality of chromophores separately by measuring each wavelength individually at the determined concentration and recorded wavelength to evaluate the spectral shape to determine the spectral signature for the chromophore; deconvolving the total absorption spectra to determine a relative contribution of each of the plurality of chromophores in the blood of a human or animal subject; and identifying at least one chromophore and its concentration in the blood of the human or animal subject from the catalog of chromophore spectra. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for non-invasively determining the relative amounts of a plurality of chromophores in the blood of a human or animal subject comprising:
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a light source imparting a wavelength range including visible and broadband infrared light to a light delivery fiberoptic; a light emission timing disk having an opening positioned between the light source and the light delivery fiber optic; a light collecting fiberoptic for receiving the wavelength range of light having passed through a selected tissue sample of the human or animal subject at a predetermined time interval according to the light emission timing disk; and a spectrometer for measuring the intensity of substantially all wavelengths of light received by the light collecting fiberoptic; and wherein a decomposition of a total absorption spectra of the measured intensity of substantially all wavelengths of light is performed through a comparison of intensity at a first wavelength to an intensity at one or more adjacent wavelengths to determine the concentration of a plurality of chromophore spectra and a catalog of this chromophore spectra is assembled with the determined concentration and wavelength to evaluate the spectral shape to determine the spectral signature for the chromophore; and at least one chromophore and its concentration in the blood of the human or animal subject from the catalog of chromophore spectra is identified. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification