Method and Apparatus for In Vivo Optical Measurement of Blood Glucose Concentration

• US 20140058226A1
• Filed: 12/22/2010
• Published: 02/27/2014
• Est. Priority Date: 12/22/2010
• Status: Abandoned Application

• Current Assignee: Verifica-BG Inc.
• Original Assignee: Verifica-BG Inc.
• Inventors: Chernobrod, Boris M., Schwartz, Vladimir
• Application Number:
  US13/996,656
• Publication Number:
  US 20140058226A1
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 5/0068 Confocal scanning
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• 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

Abstract

A method of non-invasive measurement of the glucose concentration directly in the blood flow utilizes a combination of the differential scattering spectroscopy and confocal scanning laser Doppler microscopy.

Claims

1. An optical method of non-invasive measuring of a concentration glucose in blood comprising:

providing a first laser beam at a first wavelength and a coaxially aligned second laser beam at a second wavelength, the first and the second wavelengths differing by a wavelength interval close to a sharp spectral features of glucose.

directing a portion of both laser beams to a water reference cell and controlling equal absorption in the water reference cell by tuning both wavelengths relative to the center of a water absorption window of the water reference cell;

directing the first beam into the measurement volume along a confocal optical path, scanning the first beam in the measurement volume, and obtaining a first scattered signal at the first wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the first wavelength being a signal from non-blood carrying static structures;

directing a second beam into the measurement volume along the confocal optical path, scanning the second beam in the measurement volume, and obtaining a first scattered signal at the second wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the second wavelength being a signal from non-blood carrying static structures;

directing both Doppler shifted and non-shifted signals at the first wavelength to an interferometer and mixing both signals with a first reference beam at the first wavelength, and detecting a first interference signal as an alternate current and direct current;

directing both Doppler shifted and non-shifted signals at the second wavelength to the interferometer and mixing both signals with a second reference beam at the second wavelength, and detecting a second interference signal as an alternate current and direct current;

utilizing signal processing of the first and the second interference signals to obtain a differential signal indicative of a concentration of glucose in blood.

2. The method of claim 1, wherein scanning the first and/or the second beam in the measurement volume comprising X-Y-Z scanning.

5. The method of claim 1, further comprising providing an inflatable immersion balloon of a pre-selected refractive index along the confocal optical path between the confocal arrangement and the measurement volume.

7. The method of claim 1, wherein detecting the second interference signal as the alternating current of a different frequency when both reference beam frequencies are shifted by a frequency shifter or shifters.

3. An optical method of non-invasive measuring of a concentration glucose in blood comprising:

providing a first laser beam at a first wavelength and a coaxially aligned second laser beam at a second wavelength, the first and the second wavelengths differing by a wavelength interval close to a sharp spectral features of glucose.

directing the first beam into the measurement volume along a confocal optical path, scanning the first beam in the measurement volume, and obtaining a first scattered signal at the first wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the first wavelength being a signal from non-blood carrying static structures;

directing a second beam into the measurement volume along the confocal optical path, scanning the second beam in the measurement volume, and obtaining a first scattered signal at the second wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the second wavelength being a signal from non-blood carrying static structures;

directing both Doppler shifted and non-shifted signals at the first wavelength to a first interferometer and mixing both signals with a first reference beam at the first wavelength, and detecting a first interference signal as an alternate current and direct current;

directing both Doppler shifted and non-shifted signals at the second wavelength to a second interferometer and mixing both signals with a second reference beam at the second wavelength, and detecting a second interference signal as an alternate current and direct current;

utilizing signal processing of the first and the second interference signals to obtain a differential signal indicative of a concentration of glucose in blood.

4. An optical method of non-invasive measuring of a concentration glucose in blood comprising:

providing a tunable laser source to generate a first laser beam at a first wavelength and a coaxially aligned second laser beam at a second wavelength, the first and the second wavelengths differing by a wavelength interval close to a sharp spectral features of glucose.

directing the first beam into the measurement volume along a confocal optical path, scanning the first beam in the measurement volume, and obtaining a first scattered signal at the first wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the first wavelength being a signal from non-blood carrying static structures;

directing a second beam into the measurement volume along the confocal optical path, scanning the second beam in the measurement volume, and obtaining a first scattered signal at the second wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the second wavelength being a signal from non-blood carrying static structures;

directing both Doppler shifted and non-shifted signals at the first wavelength to an interferometer and mixing both signals with a first reference beam at the first wavelength, and detecting a first interference signal as an alternate current and direct current;

directing both Doppler shifted and non-shifted signals at the second wavelength to the interferometer and mixing both signals with a second reference beam at the second wavelength, and detecting a second interference signal as an alternate current and direct current;

utilizing, signal processing of the first and the second interference signals to obtain a differential signal indicative of a concentration of glucose in blood.

6. An optical method of non-invasive measuring of a concentration glucose in blood comprising:

providing a first laser beam at a first wavelength and a coaxially aligned second laser beam at a second wavelength, the first and the second wavelengths differing by a wavelength interval close to a sharp spectral features of glucose.

directing the first beam into the measurement volume along a confocal optical path, scanning the first beam in the measurement volume, and obtaining a first scattered signal at the first wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the first wavelength being a signal from non-blood carrying static structures;

directing a second beam into the measurement volume along the confocal optical path, scanning the second beam in the measurement volume, and obtaining a first scattered signal at the second wavelength being a Doppler shifted signal scattered from dynamic objects in a blood flow, and obtaining a second scattering non-shifted signal at the second wavelength being a signal from non-blood carrying static structures;

directing, a first portion of the Doppler shifted and non-shifted signals at the first wavelength and a first portion of the Doppler shifted and non-shifted signals at the second wavelength to a first interferometer and mixing both signals with a first reference beam at the first wavelength, and detecting a first interference signal as an alternate current and direct current;

directing a second portion of the Doppler shifted and non-shifted signals at the second wavelength and a second portion of the Doppler shifted and non-shifted signals at the first wavelength to a second interferometer and mixing both signals with a second reference beam at the second wavelength, and detecting a second interference signal as an alternate current and direct current;

utilizing signal processing of the first and the second interference signals to obtain a differential signal indicative of a concentration of glucose in blood.