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

• US 9,877,670 B2
• Filed: 03/20/2017
• Issued: 01/30/2018
• 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): CERIONI, DANIEL LEE
• Application Number:
  US15/464,253
• Publication Number:
  US 20170188917A1
• Time in Patent Office: 316 Days
• Field of Search: 600310, 600316
• 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, a processor configured to receive the output signal from the at least one light detector based on the received output signal, calculate the attenuance attributable to blood in a sample present in the target area with a ratio factor, eliminate effect of uncertainty caused by temperature dependent detector response of the at least one light detector, and then determine a blood glucose level associated with a sample present in the target area based on the calculated attenuance with the processor.

Claims

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

utilizing at least one light generating structure configured 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 sample;

utilizing at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

receiving the output photocurrent signal from the at least one photocurrent signal generating light detector with a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and based on the received output photocurrent signal, wherein the at least one photocurrent signal generating light detector includes a preamplifier having a feedback resistor;

calculating the attenuance attributable to blood in a sample present in the target area with either a normalization factor or a ratio factor with the light absorbance change determining algorithm implemented processor;

eliminating effect of uncertainty caused by temperature dependent detector response of the at least one light detector with the light absorbance change determining algorithm implemented processor by calculating a 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;

determining a blood glucose level associated with a sample present in the target area with the light absorbance change determining algorithm implemented processor based on the calculated attenuance with the light absorbance change determining algorithm implemented processor; and

calculating at least one of a normalization factor Q_i(C,T) based on a preamplifier output voltage V_i (t) of an ith preamplifier as a function of time, where σ

is standard deviation according to equation;

2. The method for detecting glucose in a biological sample according to claim 1, further comprising utilizing an analog-to-digital convertor having a digitized voltage output.

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

utilizing at least one light generating structure configured 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 sample;

utilizing at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

receiving the output photocurrent signal from the at least one photocurrent signal generating light detector with a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and based on the received output photocurrent signal, wherein the at least one photocurrent signal generating light detector includes a preamplifier having a feedback resistor;

calculating the attenuance attributable to blood in a sample present in the target area with either a normalization factor or a ratio factor with the light absorbance change determining algorithm implemented processor;

eliminating effect of uncertainty caused by temperature dependent detector response of the at least one light detector with the light absorbance change determining algorithm implemented processor by calculating a 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;

determining a blood glucose level associated with a sample present in the target area with the light absorbance change determining algorithm implemented processor based on the calculated attenuance with the light absorbance change determining algorithm implemented processor;

utilizing an analog-to-digital convertor having a digitized voltage output; and

calculating at least one of a normalization factor Q_i(C,T) based on an analog to digital convertor voltage output Δ

(ADC)_i of an ith analog-to-digital convertor, where σ

is standard deviation according to the equation;