Determining material concentrations in tissues
First Claim
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1. A method of determining the relative concentration of a material in a turbid medium which comprises:
- shining light through said turbid medium;
determining the scattering coefficient of said turbid medium using said light that has passed through the turbid medium;
comparing said scattering coefficient with a previous scattering coefficient of said turbid medium, whereby a change in said scattering coefficient indicates a change in the relative concentration of said material; and
determining said relative concentration from said scattering coefficients.
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Abstract
The relative concentration of a material such as glucose in a turbid medium such as living tissue may determining the scattering coefficient of the light that has passed through the turbid medium; and comparing the scattering coefficient with a previous scattering coefficient determined with respect to the turbid medium.
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Citations
25 Claims
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1. A method of determining the relative concentration of a material in a turbid medium which comprises:
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shining light through said turbid medium; determining the scattering coefficient of said turbid medium using said light that has passed through the turbid medium; comparing said scattering coefficient with a previous scattering coefficient of said turbid medium, whereby a change in said scattering coefficient indicates a change in the relative concentration of said material; and
determining said relative concentration from said scattering coefficients. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of determining a tissue component concentration in a patient without drawing blood, which comprises placing an optical sensor head on the skin of the patient, said head carrying a first group of light sources and a light sensor, at least some of said light sources being at differing distances from said sensor and emitting light of a first wavelength, whereby pressing of said sensor against the skin permits the sensor to sense exclusively light from said light sources passing through tissue of the patient;
- passing light from said light sources in sequential manner through the tissue of said patient to the light sensor;
determining the scattering coefficient of said tissue from said light that is passed through the tissue of said patient;
comparing said scattering coefficient with a scattering coefficient previously obtained from the same portion of tissue, to obtain a relative concentration of said component of said tissue; and
determining said relative concentration from said scattering coefficients. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
- passing light from said light sources in sequential manner through the tissue of said patient to the light sensor;
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20. A method of determining the relative concentration of glucose in living cellular tissue which comprises:
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shining light through said tissue for a first time and thereafter shining light through said tissue a second time; determining the scattering coefficients of said light which is passed through said tissue during the first and second times, the wavelength of said light being substantially constant and from about 650 nm to about 1300 nm; comparing the scattering coefficients, whereby a difference in said scattering coefficients indicates a change in the relative concentration of glucose present in said tissue; and
determining said relative concentration from said scattering coefficients. - View Dependent Claims (21, 22, 23)
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24. A method of determining changing conditions in living tissue, which comprises:
- placing an optical sensor head on the skin of a patient, said head carrying a plurality of light sources and a light sensor, at least some of the light sources being at differing distances from the sensor and emitting light of essentially the same wavelength;
sequentially activating and shutting off said light sources to cause the sensor to sequentially sense light from said sources passing through said tissue;
determining the scattering coefficient from said light that has passed through said tissue;
comparing said scattering coefficient with a previous scattering coefficient of said tissue; and
determining said changing conditions from said scattering coefficients. - View Dependent Claims (25)
- placing an optical sensor head on the skin of a patient, said head carrying a plurality of light sources and a light sensor, at least some of the light sources being at differing distances from the sensor and emitting light of essentially the same wavelength;
Specification