Method and apparatus for determination of analyte concentration
First Claim
1. A method for use in measurements of the concentration of an analyte in a medium having a certain extinction coefficient spectrum, said method comprising:
- providing a selected light source unit capable of generating at least first and second radiation components, each having a selected mean wavelength and a selected spectral bandwidth such that the mean wavelength and spectral bandwidth of said first radiation component correspond to a first spectral region of the extinction coefficient spectrum of said analyte where variation of an extinction coefficient, Δ
β
1, per volume fraction of the analyte across the spectral bandwidth of the first radiation component is higher than in other spectral regions of the extinction coefficient spectrum, and the mean wavelength and second spectral bandwidth of said second radiation component correspond to a second spectral region of the extinction coefficient spectrum where variation of an extinction coefficient, Δ
β
2 per volume fraction of the analyte across the spectral bandwidth of the second radiation component is smaller than in other spectral regions of the extinction coefficient spectrum, and at least one of said at least two radiation components contains a plurality of wavelengths with radiation intensities that are in a fixed relation to each other during periods of said measurements;
irradiating the medium with said at least first and second radiation components during a certain measurement time to thereby produce detectable radiation responses of the medium thereto,analyzing data indicative of detected radiation responses of the medium to said at least first and second radiation components to determine the concentration of said analyte.
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Abstract
A method and system are presented for use in determination of the concentration of an analyte in a subject'"'"'s medium. The medium is irradiated with at least two radiation components to produce detectable radiation responses of the medium thereto. These at least two radiation components are selected to have different mean wavelengths and such that the spectral bandwidth of at least one of said at least two radiation components is characterized by relatively high variability of the extinction coefficient of the analyte of interest across said spectral bandwidth. This enables analysis of data indicative of detected radiation responses of the medium to said at least two radiation components and determination of the concentration of said analyte.
56 Citations
49 Claims
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1. A method for use in measurements of the concentration of an analyte in a medium having a certain extinction coefficient spectrum, said method comprising:
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providing a selected light source unit capable of generating at least first and second radiation components, each having a selected mean wavelength and a selected spectral bandwidth such that the mean wavelength and spectral bandwidth of said first radiation component correspond to a first spectral region of the extinction coefficient spectrum of said analyte where variation of an extinction coefficient, Δ
β
1, per volume fraction of the analyte across the spectral bandwidth of the first radiation component is higher than in other spectral regions of the extinction coefficient spectrum, and the mean wavelength and second spectral bandwidth of said second radiation component correspond to a second spectral region of the extinction coefficient spectrum where variation of an extinction coefficient, Δ
β
2 per volume fraction of the analyte across the spectral bandwidth of the second radiation component is smaller than in other spectral regions of the extinction coefficient spectrum, and at least one of said at least two radiation components contains a plurality of wavelengths with radiation intensities that are in a fixed relation to each other during periods of said measurements;irradiating the medium with said at least first and second radiation components during a certain measurement time to thereby produce detectable radiation responses of the medium thereto, analyzing data indicative of detected radiation responses of the medium to said at least first and second radiation components to determine the concentration of said analyte. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for use in determination of a hematocrit concentration, the method comprising:
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providing at least two sources of electromagnetic radiation operable in different spectral regions of a hematocrit absorption coefficient spectrum; selecting an operating spectral bandwidth of at least one of said sources of radiation such that said spectral bandwidth lies within a first spectral region of the absorption coefficient spectrum where variation of an absorption coefficient, Δ
β
1, per volume fraction of said hematocrit as a function of wavelength is higher than in other spectral regions of said absorption coefficient spectrum and such that said spectral bandwidth contains a plurality of wavelengths with radiation intensities that are in a fixed relation to each other during a measurement time;irradiating a medium with said radiation from said at least two sources of electromagnetic radiation during a certain measurement time to thereby produce detectable radiation transmitted through and/or reflected from the medium at said different spectral regions, measuring the intensity of the radiation transmitted through and/or reflected from the medium at said different spectral regions; and deriving from said transmitted and/or reflected radiation intensity a measurable relation between the medium radiation responses to different wavelengths, and analyzing said relation to determine the hematocrit concentration.
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29. A method for use in determination of the concentration of an analyte in a subject'"'"'s medium having a certain extinction coefficient spectrum, the method utilizing illumination of the medium with at least two different radiation components during a certain measurement time and detecting radiation responses of the medium to said at least two radiation components, the method comprising:
- selecting said at least two radiation components such that a first radiation component has a first mean wavelength and a first spectral bandwidth and the second radiation component has a second mean wavelength and a second spectral bandwidth, where the spectral bandwidth of said first radiation component lies within a first spectral region of the extinction coefficient spectrum where variation of an extinction coefficient, Δ
β
1, per volume fraction of the analyte as a function of wavelength is higher than in other spectral regions within said extinction coefficient spectrum, and the spectral bandwidth of the second radiation component lies within a second spectral region where variation of an extinction coefficient, Δ
β
2, per volume fraction of the analyte as a function of wavelength is smaller than in other spectral regions within said extinction coefficient spectrum, and at least said first radiation component contains a plurality of wavelengths with radiation intensity being in a fixed relation to each other during the certain measurement time, the plurality of wavelengths including at least two wavelengths that are spaced apart from one another along the first spectral region, a relation between the detected radiation responses being indicative of the concentration of said analyte.
- selecting said at least two radiation components such that a first radiation component has a first mean wavelength and a first spectral bandwidth and the second radiation component has a second mean wavelength and a second spectral bandwidth, where the spectral bandwidth of said first radiation component lies within a first spectral region of the extinction coefficient spectrum where variation of an extinction coefficient, Δ
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30. A system for use in measuring the concentration of an analyte in a subject'"'"'s medium having a certain extinction coefficient spectrum for said analyte, the system comprising a light source unit configured and operable to produce at least first and second radiation components selected such that said first radiation component has a first mean wavelength and a first spectral bandwidth and said second radiation component has a second mean wavelength and a second spectral bandwidth, where the spectral bandwidth of said first radiation component lies within a first spectral region of said extinction coefficient spectrum where variation of an extinction coefficient, Δ
- β
1, per volume fraction of the analyte across the spectral bandwidth of the first radiation component is higher than in other spectral regions within said extinction coefficient spectrum and said second spectral bandwidth lies within a second spectral region where variation of an extinction coefficient, Δ
β
2 per volume fraction of the analyte across the spectral bandwidth of the second radiation component, is smaller than in other spectral regions, and said first bandwidth contains a plurality of wavelengths with radiation intensities that are in a fixed relation to each other during a measurement time,a detector unit comprising one or more light detectors for collecting light from the medium and generating data indicative thereof, and a control unit connectable to the light source unit and to the detector unit, and being configured for processing and analyzing said data indicative of the detected light to determine a measurable relation between the detected radiation responses, and analyze said relation to derive therefrom the analyte concentration. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A system for use in determination of the concentration of an analyte in a subject'"'"'s medium having a certain extinction coefficient spectrum, the system comprising a measurement unit and a control unit connectable to the measurement unit, the measurement unit comprising a light source unit and a light detector unit, the light source unit being selected to be operable to produce at least two radiation components such that a first radiation component has a first mean wavelength and a first spectral bandwidth and a second radiation component has a second mean wavelength and a second spectral bandwidth, where the spectral bandwidth of said first radiation component lies within a first spectral region of said extinction coefficient spectrum where variation of an extinction coefficient, Δ
- β
1 per volume fraction of the analyte across the spectral bandwidth of the first radiation component, is higher than in other spectral regions within said extinction coefficient spectrum and the spectral bandwidth of said second radiation component lies within a second spectral region of said extinction coefficient spectrum where variation of an extinction coefficient, Δ
β
2 per volume fraction of the analyte across the spectral bandwidth of the second radiation component, is smaller than in other spectral regions within said extinction coefficient spectrum and said at least one radiation component containing a plurality of wavelengths with radiation intensity being in a fixed relation to each other during a measurement time, the light detector unit comprising one or more light detectors adapted for collecting the radiation components after being transmitted through and/or reflected from the illuminated subject'"'"'s medium and generating data indicative of the collected light components, the control unit being configured for analyzing said data to determine a measurable relation between the collected light components and analyze said relation to derive therefrom the analyte concentration.
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Specification