Optical measurement of parameters related to motion of light-scattering particles within a fluid by manipulating analog electrical signals
First Claim
1. A method for obtaining physiological information about a subject, the method comprising:
- a) illuminating a portion of the subject'"'"'s skin to scatter partially or entirely coherent light off of moving red blood cells (RBCs) within the subject'"'"'s blood to influence a location-dependent light field;
b) detecting light of the location-dependent light field at first and second locations to respectively generate first and second analog electrical signals that respectively describe the light field at the first and second locations;
c) generating a difference analog electrical signal that describes a difference between the first and second analog signals;
d) analyzing the difference analog electrical signal or a derivative thereof to characterize time fluctuations of a coherent light interference pattern described by the difference analog signal; and
e) deriving, according to results of the analysis, at least one physiological parameter of the subject.
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Accused Products
Abstract
The present invention relates to an apparatus and method for optical measurement of a parameter related to motion of light-scattering particles within a fluid by manipulating analog electrical signals. In some embodiments, first and second analog signals are respectively obtained from first and second photodetectors respectively located at first and second locations. A technique is disclosed for boosting a fraction of an analog electrical signal attributable to light scattering fluctuations and/or to stochastic effects and/or to speckle measurements and/or to DLS measurements. According to this technique, a hybrid analog signal or a difference analog signals is obtained from the first and second analog signals, and is analyzed. Exemplary fluids include but are not limited to biological fluids (e.g. blood plasma). Teachings disclosed herein may be employed in vitro or in vivo.
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Citations
69 Claims
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1. A method for obtaining physiological information about a subject, the method comprising:
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a) illuminating a portion of the subject'"'"'s skin to scatter partially or entirely coherent light off of moving red blood cells (RBCs) within the subject'"'"'s blood to influence a location-dependent light field; b) detecting light of the location-dependent light field at first and second locations to respectively generate first and second analog electrical signals that respectively describe the light field at the first and second locations; c) generating a difference analog electrical signal that describes a difference between the first and second analog signals; d) analyzing the difference analog electrical signal or a derivative thereof to characterize time fluctuations of a coherent light interference pattern described by the difference analog signal; and e) deriving, according to results of the analysis, at least one physiological parameter of the subject. - View Dependent Claims (2, 4, 5, 6, 7, 10, 12)
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3. (canceled)
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8. (canceled)
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9. (canceled)
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11. (canceled)
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13-15. -15. (canceled)
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16. Apparatus for obtaining physiological information about a subject, the apparatus comprising:
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a) one or more sources of partially or entirely coherent light configured to illuminate a portion of the subject'"'"'s skin to scatter partially or entirely coherent light off of moving red blood cells (RBCs) within the subject'"'"'s blood to influence a location- dependent light field; b) a plurality of photodetectors including first and second photodetectors respectively configured to detect light of the location-dependent light field at first and second locations to respectively generate first and second analog electrical signals that respectively describe the light field at the first and second locations; c) electronic circuitry including analog circuitry that is configured to generate a difference analog electrical signal that describes a difference between the first and second analog signals, the electronic circuitry further configured to; i) analyze the difference analog electrical signal or a derivative thereof to;
characterize time fluctuations of a coherent light interference pattern described by the difference analog signal; andii) derive, according to results of the analysis, at least one physiological parameter of the subject.
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17-18. -18. (canceled)
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19. An apparatus for obtaining information related to the movement of particles within a fluid, the apparatus comprising:
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a) one or more light sources configured to induce a light response signal by applying partially or entirely coherent light so that at least some of the light is scattered by the moving particles within the fluid, the light response signal contributing to a location- dependent light field; b) a detection system including first and second photodetectors respectively located at first and second locations, the photodetectors respectively configured to respectively generate, from the light field at the first and second locations, first and second photodetector analog electrical signals; c) electronic circuitry including analog circuitry that is configured to generate, from the first and second photodetector analog electrical signals, a difference analog electrical signal describing a difference between the light field at the first location and the light field at the second location, the electronic circuitry being configured, when a power level of the difference analog electrical signal is significantly less than a power level of the first and/or second analog electrical signals, to; i) analyze the analog difference signal or a derivative thereof to characterize time fluctuations of a coherent light interference pattern described by the analog difference signal; and ii) deriving, from results of the analysis, at least one of; A) information describing the motion of the particles within the fluid; B) a physiological or biological parameter related to motion of the particles within the fluid. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 68, 69)
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27-67. -67. (canceled)
Specification