Non-Invasive Device and Method for Measuring a Substance Concentration

• US 20150196233A1
• Filed: 01/12/2015
• Published: 07/16/2015
• Est. Priority Date: 01/10/2014
• Status: Active Grant

• Current Assignee: GlucoVista, Inc., Medical Coherence LLC
• Original Assignee: GlucoVista, Inc.
• Inventors: Gerlitz, Yonatan
• Granted Patent: US 9,795,329 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• 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 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/6816 Ear lobe
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

A system includes a light source and a light detector. The system further includes a first optical system configured to direct a transmitted portion of light onto the detector. The first optical system is further configured to block a scattered portion of the light. The system also includes a second optical system configured to direct the transmitted and scattered portions of the light onto the detector.

Claims

1. A method comprising:

measuring transmitted light from a body for at least one wavelength band via a first optical system;

measuring scattered light from the body for the at least one wavelength band via a second optical system;

determining a substance concentration in the body based on a predetermined correlation between measurement data and the substance concentration, the measurement data being associated with the measured transmitted light and the measured scattered light.

2. The method of claim 1, further comprising:

measuring other transmitted light from the body for a second wavelength band via the first optical system;

measuring other scattered light from the body for the second wavelength band via the second optical system, the measurement data being further associated with the measured other scattered light and the measured other transmitted light.

3. The method of claim 2, further comprising:

calculating a scattered light ratio parameter based on a ratio of the measured scattered light for the at least one wavelength to the measured other scattered light for the second wavelength;

calculating a transmitted light ratio parameter based on a ratio of the measured transmitted light for the at least one wavelength to the measured other transmitted light for the second wavelength, the measurement data including the scattered light ratio parameter and the transmitted light ratio parameter.

4. The method of claim 1, further comprising:

measuring an ambient temperature;

measuring a body surface temperature;

measuring a body temperature; and

before determining the substance concentration, modifying the measurement data, the predetermined correlation, or both, based on the ambient temperature, the body surface temperature, and the body temperature.

5. The method of claim 1, further comprising modulating the light source.

6. The method of claim 1, wherein the substance is glucose.

7. A non-transitory computer-readable medium storing instructions that, when executed by a processor, causes the processor to initiate or perform operations comprising:

receiving a measurement of transmitted light from a body for at least one wavelength band via a first optical system;

receiving a measurement of scattered light from the body for the at least one wavelength band via a second optical system; and

determining a substance concentration in the body based on a predetermined correlation between measurement data and a glucose concentration, the measurement data being associated with the measurement of transmitted light and the measurement of scattered light.

8. A system comprising:

a light source;

a light detector;

a first optical system configured to direct a transmitted portion of light onto the detector and further configured to block a scattered portion of the light; and

a second optical system configured to direct the transmitted and scattered portions of light onto the detector.

9. The system of claim 8, the light source including a near-infrared (NIR) laser diode and a collimating lens configured to selectively generate a collimated NIR light beam in at least a first wavelength band and a second wavelength band.

10. The system of claim 8, the light source including a first NIR laser diode configured to generate a collimated NIR light beam in a first wavelength band and a second NIR laser diode configured to generate a collimated NIR light beam in a second wavelength band.

11. The system of claim 8, the first optical system including a lens with a f-number of f/3 or greater.

12. The system of claim 11, the first optical system further including one or more field limiters to inhibit receipt of the scattered portion of the light at the lens.

13. The system of claim 8, the second optical system including a lens with a f-number of f/1 or smaller.

14. The system of claim 8, the scattered light including light scattered by a body within a range of small-angle scattering.

15. The system of claim 8, further comprising a motor configured to selectively position the first optical system or the second optical system between the light source and the light detector.

16. The system of claim 8, further comprising an interference filter configured to pass light within a first wavelength band, a substance affecting absorption of light by the body within the first wavelength band, and block light within a second wavelength band, the substance having no or negligible effect on absorption of light by the body within the second wavelength band.

17. The system of claim 16, further comprising a motor configured to selectively position the interference filter between the light source and the light detector.

18. The system of claim 8, the detector comprising at least one material selected from silicon, aluminum gallium arsenide, and combinations thereof.

19. The system of claim 8, the detector coupled to a lock-in amplifier to reduce detection of light noise from other light sources.

20. The system of claim 8, further comprising a processor and memory, wherein the memory includes instructions that, when executed by the processor, cause the processor to initiate or perform operations including:

receiving a measurement of transmitted light from a body for at least one wavelength band via a first optical system;

receiving a measurement of scattered light from the body for the at least one wavelength band via a second optical system;

determining a substance concentration in the body based on a predetermined correlation between measurement data and the substance concentration, the measurement data being associated with the measurement of transmitted light and the measurement of scattered light.