Method and apparatus for non-invasive measurement of blood analytes
First Claim
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1. A non-invasive method of evaluating constituents in the blood of a patient comprising the steps of:
- directing a beam of radiation to the target tissue;
measuring a first response spectrum;
modulating the target tissue to change the amount of blood in the region that is exposed to the radiation;
measuring a second response spectrum;
modulating the target tissue to change the amount of blood in the region that is exposed to the radiation;
measuring a third response spectrum;
comparing the first, second and third response spectra to identify those portions of the response most closely associated with blood in the tissue; and
predicting the constituents in the blood based on the results of the compared spectra.
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Abstract
The present invention discloses a method and apparatus and method for achieving non-invasive measurement of analytes from human and animal blood through the skin using Raman lightwave technology. The apparatus includes a hydraulic tissue permeation unit, which controls the amount of blood in the laser tissue interaction region. Two or more spectra are obtained at different blood levels. These spectra are used to improve the measurements.
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Citations
23 Claims
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1. A non-invasive method of evaluating constituents in the blood of a patient comprising the steps of:
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directing a beam of radiation to the target tissue;
measuring a first response spectrum;
modulating the target tissue to change the amount of blood in the region that is exposed to the radiation;
measuring a second response spectrum;
modulating the target tissue to change the amount of blood in the region that is exposed to the radiation;
measuring a third response spectrum;
comparing the first, second and third response spectra to identify those portions of the response most closely associated with blood in the tissue; and
predicting the constituents in the blood based on the results of the compared spectra. - View Dependent Claims (2, 3, 4, 5)
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6. A non-invasive method of evaluating constituents in the blood of a patient comprising the steps of:
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applying a first negative pressure to a region of target tissue to increase the blood flow into that region;
directing optical radiation to the region;
measuring a first Raman response spectrum;
applying a second negative pressure to a region of the target tissue, said second negative pressure being different from said first negative pressure so that the blood flow in that region is changed;
measuring a second Raman response spectrum;
comparing the first and second response spectra to identify those portions of the response most closely associated with blood in the tissue; and
predicting the constituents in the blood based on the results of the compared spectra. - View Dependent Claims (7, 8, 9)
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10. A non-invasive method of evaluating constituents in the blood of a patient comprising the steps of:
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applying a first negative pressure to a region of target tissue to increase the blood flow in that region;
directing narrowband optical radiation to the region;
measuring a first Raman response spectrum;
applying a second negative pressure to the region of the target tissue, said second negative pressure being less than the first negative pressure so that blood flow in the region is reduced;
measuring a second Raman response spectrum;
subtracting the second spectrum from the first spectrum; and
predicting the constituents in the blood based on the results of the subtraction. - View Dependent Claims (11, 12, 13)
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14. A non-invasive method of evaluating constituents in the blood of a patient comprising the steps of:
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applying a first negative pressure to a region of target tissue to increase the blood flow in that region;
directing narrowband optical radiation to the region;
measuring a first Raman response spectrum;
applying a second negative pressure to the region of the target tissue, said second negative pressure being less than the first negative pressure so that blood flow in the region is reduced;
measuring a second Raman response spectrum;
applying a third negative pressure to the region of the target tissue, said third negative pressure being less than the second negative pressure so that blood flow in the region is reduced;
measuring a third Raman response spectrum;
subtracting the third spectrum from the first spectrum and subtracting the third spectrum from the second spectrum to obtain two difference spectra; and
evaluating the constituents in the blood based on the results of the subtractions. - View Dependent Claims (15)
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16. An apparatus for non-invasively evaluating the constituents in the blood of a patient comprising:
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a chamber having an opening which in use is at least partially covered by the target tissue of the patient;
a light source for directing radiation to the target tissue;
a detector for monitoring the spectral response from the target tissue and generating output signals in response thereto;
a pump for changing the pressure in the chamber in order to change the level of blood in the region of the target tissue; and
a processor for comparing the spectral responses obtained at least three different pressure levels in the chamber in order to help discriminate between the spectral response associated with the blood and the spectral response associated with the tissue, said processor further functioning to evaluate the constituents in the blood based on the results of the comparison. - View Dependent Claims (17)
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18. An apparatus for non-invasively evaluating the constituents in the blood of a patient comprising:
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a chamber having an opening which in use is at least partially covered by the target tissue of the patient;
a laser light source for directing narrow band optical radiation to the target tissue;
a spectrometer detector for monitoring the Raman spectral response from the target tissue and generating output signals in response thereto;
a pump for changing the pressure in the chamber in order to change the level of blood in the region of the target tissue; and
a processor for deriving a difference spectrum by comparing the spectral responses obtained at least three different pressure levels in the chamber in order to help discriminate between the spectral response associated with the blood and the spectral response associated with the tissue, said processor further functioning to evaluate the constituents in the blood based on the results of the comparison. - View Dependent Claims (19, 20, 21, 22)
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23. An apparatus for non-invasively evaluating the constituents in the blood of a patient comprising:
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a laser light source for directing narrow band optical radiation to the target tissue;
a spectrometer detector for monitoring the Raman spectral response from the target tissue and generating output signals in response thereto;
means for changing the level of blood in the region of the target tissue; and
a processor for deriving a difference spectrum by comparing the spectral responses obtained at least three different levels of blood in the target tissue in order to help discriminate between the spectral response associated with the blood and the spectral response associated with the tissue, said processor further functioning to evaluate the constituents in the blood based on the results of the comparison.
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Specification