Method and apparatus for monitoring glucose levels in a biological tissue
First Claim
1. A method of monitoring the blood glucose concentration within a biological tissue comprising the steps of:
- providing light having scattering properties sensitive to the glucose concentration within the tissue;
continuously scanning the light over a two-dimensional area of the tissue and, at the same time, interferometrically scanning the tissue in depth; and
collecting the reflected light to determine the concentration of glucose in the tissue
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Accused Products
Abstract
In accordance with the invention, a low coherence interferometer is used to non-invasively monitor the concentration of glucose in blood by shining a light over a surface area of human or animal tissue, continuously scanning the light over a two dimensional area of the surface, collecting the reflected light from within the tissue and constructively interfering this reflected light with light reflected along a reference path to scan the tissue in depth. Since the reflection spectrum is sensitive to glucose concentration at particular wavelengths, measurement and analysis of the reflected light provides a measure of the level of glucose in the blood. The measurement of glucose is taken from multiple depths within blood-profused tissue, and sensitivity is preferably enhanced by the use of multiple wavelengths. Noise or speckle associated with this technique is minimized by continuously scanning the illuminated tissue in area and depth.
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Citations
35 Claims
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1. A method of monitoring the blood glucose concentration within a biological tissue comprising the steps of:
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providing light having scattering properties sensitive to the glucose concentration within the tissue;
continuously scanning the light over a two-dimensional area of the tissue and, at the same time, interferometrically scanning the tissue in depth; and
collecting the reflected light to determine the concentration of glucose in the tissue - View Dependent Claims (2, 3, 4, 5)
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6. A method of measuring blood glucose concentration within a human or animal subject comprising the steps of:
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providing light of at least two different wavelengths, each having different absorption or different scattering properties for glucose-containing tissues;
splitting the light into a sample beam and a reference beam;
illuminating and scanning the tissue of the subject with the sample beam;
collecting the sample light reflected from within the illuminated subject tissue;
interfering the reflected light with the reference beam; and
measuring the interfered light and processing the measurements to determine the concentration of glucose in the blood of the subject tissue. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 26, 35)
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17. An apparatus for measuring the blood glucose concentration of a human or animal subject comprising:
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one or more sources of light to provide light at two or more wavelengths;
a first light path to direct a beam of sample light from the source or sources onto the subject tissue;
a second light path to direct a beam of reference light from the source or sources to a phase shifter;
a scanner to scan the sample light over an area of the subject tissue;
an interferometer to interfere reflected sample light from the subject tissue with the reference light, the phase of the reference light path adjusted to constructively interfere with reflected sample light from multiple depths;
one or more photodetectors to measure the interfered light; and
a processor to calculate glucose concentration from the measurements. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 27)
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28. A method of measuring blood glucose concentration within a biological sample including blood, the method comprising the following steps:
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providing a low coherence interferometer comprising a sample optical beam, a reference optical beam, a reference path phase shifter and one or more photodetectors;
providing a light source for providing a sample beam for illuminating the sample and a reference beam;
scanning the illuminated sample over a two dimensional area with the sample beam;
interfering the sample light reflected from the sample with the reference beam to select light reflected within the sample blood; and
collecting and processing the interfered light to calculate a measurement of the concentration of glucose in the blood. - View Dependent Claims (29, 30, 31, 32, 33, 34)
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Specification