Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis

• US 9,788,764 B2
• Filed: 09/11/2012
• Issued: 10/17/2017
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: St. Louis Medical Devices, Inc.
• Original Assignee: St. Louis Medical Devices, Inc.
• Inventors: Xu, Zhi
• Primary Examiner(s): DOUGHERTY, SEAN PATRICK
• Application Number:
  US13/610,342
• Publication Number:
  US 20130006072A1
• Time in Patent Office: 1,862 Days
• Field of Search: 600309, 600310, 600316, 600322, 600323, 600335, 600336
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

Systems and methods are disclosed for non-invasively measuring blood glucose levels in a biological sample based on spectral data. This includes at least one light source configured to strike a target area of a sample, at least one light detector positioned to receive light from the at least one light source and to generate an output signal, having a time dependent current, which is indicative of the power of light detected, and a processor configured to receive the output signal from the at least one light detector and based on the received output signal, calculate the attenuance attributable to blood in a sample present in the target area and eliminate effect of uncertainty caused by temperature dependent detector response of the at least one light detector, and based on the calculated attenuance, determine a blood glucose level associated with a sample present in the target area.

Claims

1. A system for detecting glucose in a biological sample, comprising:

at least one light beam generating structure generating one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

at least one photocurrent signal generating light detector containing one or more photodiodes positioned to receive detected blood glucose level information in the one or more light beams and to transform the detected blood glucose level information in the one or more light beams to the detected blood glucose level information in an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected; and

a blood glucose level caused light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and configured to receive the output photocurrent signal from the at least one light detector and based on the received output photocurrent signal, calculate attenuance attributable to blood in a sample present in the target area and eliminate effect of uncertainty caused by temperature dependent detector response of the at least one light detector by calculating standard deviation of a logarithm of the time dependent output current generated by the light power from the same target area of the biological sample, and based on the calculated attenuance, determine a blood glucose level associated with a sample present in the target area.

2. The system for detecting glucose in a biological sample according to claim 1, wherein the processor is configured to eliminate the effect of uncertainty caused by temperature of the at least one light detector by calculating the following equation with the processor:

σ

[log I_D(λ

_i,t)]=σ

[log P(λ

_i,t], where the ith wavelength being represented by λ

_i, based on the time dependent detector output current signal I_D(λ

_i,t) and the time dependent detector power signal P(λ

_i,t), where log I_D(λ

_i,t) is the logarithm of the time dependent detector output current signal and log P(λ

_i,t) is the logarithm of the time dependent light power received by the corresponding detector.

3. The system for detecting glucose in a biological sample according to claim 1, wherein the at least one light detector includes a preamplifier having a feedback resistor.

4. A method for detecting glucose in a biological sample, comprising:

utilizing at least one light beam generating structure to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

utilizing at least one photocurrent signal generating light detector positioned to receive detected blood glucose level information in the one or more light beams and to transform the detected blood glucose level information in the one or more light beams to the detected blood glucose level information in an output photocurrent signal, having a time dependent current, which is indicative of power of light detected;

receiving the output photocurrent signal from the at least one light detector with a processor and based on the received output photocurrent signal, wherein the processor is programmed to implement a blood glucose level caused light absorbance change determining algorithm to calculate a change in a light absorption caused by blood in the biological sample;

calculating attenuance attributable to blood in a biological sample present in the target area with the processor;

eliminating effect of uncertainty caused by temperature dependent detector response of the at least one light detector with the processor by calculating standard deviation of a logarithm of the time dependent output current generated by the light power from the same target area of the biological sample; and

determining a blood glucose level associated with a biological sample present in the target area based on the calculated attenuance with the processor.

5. The method for detecting glucose in a biological sample according to claim 4, wherein the step of eliminating effect of uncertainty caused by temperature dependent detector response of the at least one light detector further includes calculating the following equation with the processor:

σ

[log I_D(λ

_i,t)]=σ

[log P(λ

_i,t)], where the ith wavelength being represented by λ

_i, based on the time dependent detector output current signal I_D(λ

_i,t) and the time dependent detector power signal P(λ

_i,t), where log I_D(λ

_i,t) is the logarithm of the time dependent detector output current signal and log P(λ

_i,t) is the logarithm of the time dependent light power received by the corresponding detector.

6. The method for detecting glucose in a biological sample according to claim 4, wherein the step of utilizing at least one light detector includes utilizing a preamplifier having a feedback resistor.