Non-invasive sensor capable of determining optical parameters in a sample having multiple layers
First Claim
1. A method for determining at least one optical parameter of a sample, said sample having a plurality of layers, each of said layers having different properties, said method comprising the steps of:
- a) introducing a beam of light into said sample at a light introduction site on a surface of said sample;
b) determining the intensities of light re-emitted from said sample at a plurality of light collection sites on said surface of said sample, at least a first light collection site collecting light re-emitted mainly from a first layer of said sample, at least a second light collection site collecting light re-emitted mainly from a second layer of said sample, said first light collection site being at a first distance from said light introduction site, and said second light collection site being at a second distance from said light introduction site, said first distance being less than said second distance;
c) determining at least one optical parameter of said first layer of said sample; and
d) determining at least one optical parameter of said second layer of said sample, said first layer having an average depth, as measured from said surface of said sample, of smaller magnitude than the average depth of said second layer, as measured from said surface of said sample.
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Abstract
Apparatus and method for non-invasively measuring at least one optical parameter of a sample, particularly a sample of tissue that comprises a plurality of layers. The at least one parameter can be used to determine the presence or concentration of an analyte of interest in the sample of tissue. The apparatus and method of the present invention (1) measure light that is substantially reflected, scattered, absorbed, or emitted from a shallower layer of the sample of tissue, (2) measure light that is substantially reflected, scattered, absorbed, or emitted from a deeper layer of the sample of tissue, (3) determine at least one optical parameter for each of these layers, and (4) account for the effect of the shallower layer on the at least one optical parameter of the deeper layer. Specifying the sampling depth allows determinations of the optical properties of a specific layer of the sample of the tissue, e.g., dermis, and decreases interference from other layers, e.g., stratum corneum and epidermis, in these determinations.
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Citations
46 Claims
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1. A method for determining at least one optical parameter of a sample, said sample having a plurality of layers, each of said layers having different properties, said method comprising the steps of:
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a) introducing a beam of light into said sample at a light introduction site on a surface of said sample;
b) determining the intensities of light re-emitted from said sample at a plurality of light collection sites on said surface of said sample, at least a first light collection site collecting light re-emitted mainly from a first layer of said sample, at least a second light collection site collecting light re-emitted mainly from a second layer of said sample, said first light collection site being at a first distance from said light introduction site, and said second light collection site being at a second distance from said light introduction site, said first distance being less than said second distance;
c) determining at least one optical parameter of said first layer of said sample; and
d) determining at least one optical parameter of said second layer of said sample, said first layer having an average depth, as measured from said surface of said sample, of smaller magnitude than the average depth of said second layer, as measured from said surface of said sample. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for measuring at least one optical parameter of a sample having a plurality of layers having differing properties, said method comprising the steps of:
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a) introducing a beam of light into said sample at a light introduction site;
b) collecting light re-emitted from said sample at a plurality of light collection sites, each of said light collection sites comprising at least two light collecting elements, each of said light collection sites located at a different distance from said light introduction site;
c) determining the intensity of said light re-emitted at a first light collecting element of a light collection site located at a first distance from said light introduction site and the intensity of said light re-emitted at at least a second light collecting element of said light collection site located at said first distance from said light introduction site;
d) determining the absorption coefficient and the scattering coefficient of said sample at a given depth of said sample by means of a mathematical relationship between intensity of said light re-emitted at said first light collecting element of said light collection site located at said first distance from said light introduction site and intensity of said light re-emitted at at least a second light collecting element of said light collection site located at said first distance from said light introduction site;
e) determining the intensity of said light re-emitted at a first light collecting element of a light collection site located at a second distance from said light introduction site and the intensity of said light re-emitted at at least a second light collecting element of said light collection site located at said second distance from said light introduction site, wherein said second distance is greater than said first distance;
f) determining the absorption coefficient and the scattering coefficient of the sample at a greater depth of said sample than that of step d) by means of a mathematical relationship between intensity of said light re-emitted at said first light collecting element of said light collection site located at said second distance from said light introduction site and intensity of said light re-emitted at at least a second light collecting element of said light collection site located at said second distance from said light introduction site. - View Dependent Claims (8, 9, 10, 11, 13, 14, 15, 16, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29)
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12. An apparatus for measuring at least one optical parameter of a sample having a plurality of layers having different properties, said apparatus comprising:
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a) a source of light;
b) means for introducing light from said source of light into said sample at a light introduction site on a surface of said sample;
c) a plurality of light collecting elements for collecting light re-emitted from said sample at a plurality of light collection sites on said surface of said sample;
d) at least one detector for determining the intensity of light collected at said light collection sites;
e) a means for computing said at least one optical parameter of said sample.
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17. An apparatus for measuring at least one optical parameter of a sample having layers having different properties comprising:
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a) at least one source of light for introducing light to a defined area on a surface of said sample;
b) at least two groups of light collecting elements, each of said groups of light collecting elements comprising at least two light collecting elements, each of said groups of light collecting elements located at a different distance from said defined area on said surface of said sample;
c) at least one detector for measuring light collected by said light collecting elements; and
d) a signal processor to determine said at least one optical parameter of said sample.
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24. A method for determining at least one optical parameter of a sample, said sample having a plurality of layers, each of said layers having different properties, said method comprising the steps of:
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a) introducing a plurality of beams of light into said sample at a plurality of light introduction sites on a surface of said sample, a first light introduction site being at a first distance from a light collection site on said surface of said sample, a second light introduction site being at a second distance from said light collection site on said surface of said sample, said first distance being less than said second distance;
b) determining the intensities of light re-emitted from said sample at said light collection site, said light collection site collecting light re-emitted mainly from a first layer of said sample and collecting light re-emitted mainly from a second layer in said sample, said light re-emitted from said first layer being introduced at said first light introduction site, said light re-emitted from said second layer being introduced at said second light introduction site;
c) determining at least one optical parameter of a said first layer of said sample; and
d) determining at least one optical parameter of said second layer of said sample, said first layer having an average depth, as measured from said surface of said sample, of smaller magnitude than the average depth of said second layer, as measured from said surface of said sample.
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30. A method for measuring at least one optical parameter of a sample having layers having differing properties, said method comprising the steps of:
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a) introducing beams of light into said sample at a plurality of light introduction sites by a plurality of groups of illuminating elements, at least two illuminating elements being at each of said light introduction sites, each of said light introduction sites located at a different distance from a light collection site;
b) collecting light re-emitted from said sample at said light collection site;
c) determining the intensity of said re-emitted light resulting from illumination by a first illuminating element of a light introduction site located at a first distance from said light collection site and the intensity of said re-emitted light resulting from illumination by at least a second illuminating element of said light introduction site located at said first distance from said light collection site;
d) determining the absorption coefficient and the scattering coefficient of said sample at a given depth in said sample by means of a mathematical relationship between intensity of said re-emitted light resulting from illumination by said first illuminating element of said light introduction site located at said first distance from said light collection site and intensity of said re-emitted light resulting from illumination by at least a second illuminating element of said light introduction site located at said first distance from said light collection site;
e) determining the intensity of said re-emitted light resulting from illumination by a first illuminating element of a light introduction site located at a second distance from said light collection site and the intensity of said re-emitted light resulting from illumination by at least a second illuminating element of said light introduction site located at said second distance from said light collection site, wherein said second distance is greater than said first distance;
f) determining the absorption coefficient and the scattering coefficient of said sample at a greater depth of said tissue than that of step d) by means of a mathematical relationship between intensity of said re-emitted light resulting from illumination by said first illuminating element of said light introduction site located at said second distance from said light collection site and intensity of said re-emitted light resulting from illumination by at least a second illuminating element of said light introduction site located at said second distance from said light collection site. - View Dependent Claims (31, 32, 33, 34, 36, 37, 38, 39)
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35. An apparatus for measuring at least one optical parameter of a sample, said sample having a plurality of layers having different properties, said apparatus comprising:
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a) at least one source of light;
b) a plurality of means for introducing light from said at least one source of light into said sample at a plurality of light introduction sites on a surface of said sample;
c) a light collection site for collecting light re-emitted from said sample;
d) at least one detector for determining the intensity of light collected at said light collection site; and
e) a means for computing said at least one optical parameter of said sample.
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40. An apparatus for measuring at least one optical parameter of a sample, said sample having layers having different properties, said apparatus comprising:
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a) at least one source of light for introducing light to defined areas on a surface of said sample;
b) at least two groups of illuminating elements, each of said groups of light illuminating elements comprising at least two illuminating elements, each of said groups of illuminating elements located at a different distance from a light collection site on said surface of said sample;
c) at least one detector for determining the intensity of light collected at said light collection site; and
c) a signal processor to determine said at least one optical parameter of said sample. - View Dependent Claims (41, 42, 43, 44, 45, 46)
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Specification