Method and device for measuring concentration of glucose or other substances in blood

A method for determining the concentration of a scattering affecting or optically active substance in a patient's blood, the method comprising the steps of:

• (i) providing reference data indicative of a preset measurable parameter as a function of values of said concentration;
• (ii) creating a state of blood flow cessation within a measurement location in a blood flow containing medium, and maintaining said state during a certain cessation time;
• (iii) performing optical measurement sessions within a time period including said certain cessation time, the optical measurements including illumination the measurement location with incident light of at least one selected wavelength, detection, at each measurement session, of at least two light responses of the medium characterized by at least two different polarization states of detected light, respectively, and generation of measured data representative thereof;
• (iv) utilizing the measured data for obtaining measurement results in the form of at least two kinetic curves of the light responses of the medium as functions of time corresponding to the different polarization states of the detected light;
• (v) analyzing said at least two kinetic curves for calculating said certain measurable parameter indicative of relation between them;
• and
• (vi) utilizing the calculated value and said reference data for determining the concentration of the substance in the patient's blood.

A method for non-invasively determining the concentration of a substance in a patient's blood, the method comprising the steps of:

• providing reference data indicative of a preset measurable parameter as a function of values of said concentration;
• applying over-systolic pressure to a location of the patient's blood perfused fleshy medium, thereby creating a state of blood flow cessation within a measurement location downstream of the location of application of pressure with respect to the blood flow direction, and maintaining said state of the blood flow cessation during a certain cessation time being insufficient for irreversible changes in the fleshy medium;
• performing optical measurement sessions within a time period including said certain cessation time, the optical measurements including illumination of the measurement location with incident light of at least one selected wavelength, detection, at each measurement session, of at least two light responses of the medium characterized by at least two different polarization states of detected light, respectively, and generation of data representative thereof;
• utilizing the measured data for obtaining measurement results in the form of at least two kinetic curves of the light responses of the medium as functions of time corresponding to the different polarization states of the detected light;
• analyzing said at least two kinetic curves for calculating said certain parameter indicative of relation between them, and
• utilizing the calculated value and said reference data for determining the concentration of the substance in the patient's blood.

An optical measurement system for obtaining data indicative of the concentration of a scattering affecting or optically active substance in patient's blood, the system comprising:

• (a) a measurement device comprising a pressurizing assembly and a measuring unit, wherein the pressurizing assembly has a pressing member for wrapping a region on a blood flow containing medium that is operable for applying over-systolic pressure to said region so as to create a state of blood flow cessation at a measurement location in the medium, and the measuring unit is operable for performing optical measurement sessions at said measurement location, and comprises an illumination system for illuminating the measurement location with specifically polarized light of at least one selected wavelength during at least two measurement sessions, and a light collection/detection system for applying polarization filtering to light propagating from the measurement location, thereby enabling detecting, at each measurement session, at least two light responses of the medium characterized by the same wavelength and at least two different polarization states, respectively, and generating measured data representative thereof;
• and
• (b) a control unit connectable to the measurement device for selectively operating said measuring unit and said pressurizing assembly, such that the state of blood flow cessation is maintained during a certain cessation time and the optical measurement sessions are performed during a time period within said certain cessation time, the control unit being responsive to said measured data to determine time variations of the light responses of the medium corresponding to said at least two different polarization states of the detected light, analyze the time variations for determining a preset parameter measured as a relation between the time variations, and being indicative of the time variation of depolarization of light caused by the scattering affecting or optically active substance in the medium.

A measurement system for non-invasively determining the concentration of a substance in a patient's blood, the system comprising:

• a measurement device that comprises a pressurizing assembly operable to apply over-systolic pressure to a location on the patient's blood perfused fleshy medium, so as to create a state of blood flow cessation at a measurement location in the medium located downstream of the location of application of pressure;
• and comprises a measuring unit operable to perform optical measurement sessions to said measurement location, the measuring unit comprising an illumination system and a light collection/detection system which are operable so as to detect at least two light responses of the medium characterized by at least two different polarization states of detected light, respectively, and generate measured data representative thereof;
• and
• a control unit connectable to the measurement device for selectively operating said measuring unit and said pressurizing assembly, such that the state of blood flow cessation is maintained during a certain cessation time being insufficient for irreversible changes in the fleshy medium, and the optical measurement sessions are performed within a time period including said cessation time, the control unit being responsive to said measured data to determine time variations of said at least two light responses of the medium corresponding to at least two different polarization states of the detected light, analyze the time variations for determining a preset parameter measured as a relation between the time variations, and determining the concentration of said substance using reference data indicative of the preset measurable parameter as a function of values of the substance concentration.