Noninvasive apparatus and method for measuring blood sugar concentration

• US 20080188724A1
• Filed: 12/17/2007
• Published: 08/07/2008
• Est. Priority Date: 02/01/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hwang, In Duk, Shin, Kun Soo
• Granted Patent: US 8,306,593 B2
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• 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 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

An apparatus noninvasively measures blood sugar concentration. The apparatus includes: a tissue modulation unit applying a pressure to a tissue; a hemoglobin (Hb) concentration measurement unit analyzing an amount of absorption of electromagnetic waves on a first portion of the tissue before and after the applying of the pressure by the tissue modulation unit, and measuring Hb concentration of the tissue; and a photoacoustic module unit analyzing photoacoustic signals to measure blood sugar concentration, and correcting the measured blood sugar concentration based on the measured Hb concentration to output a final blood sugar level, the photoacoustic signals being created from the tissue by emitting a pulse laser ray towards a second portion of the tissue before and after the applying of the pressure by the tissue modulation unit.

Claims

1. An apparatus to measure blood sugar concentration noninvasively, the apparatus comprising:

a tissue modulation unit applying a pressure to a tissue;

a hemoglobin (Hb) concentration measurement unit analyzing an amount of absorption of electromagnetic waves on a first portion of the tissue before and after the applying of the pressure by the tissue modulation unit, and measuring Hb concentration of the tissue; and

a photoacoustic module unit analyzing photoacoustic signals to measure blood sugar concentration, correcting the measured blood sugar concentration based on the measured Hb concentration to measure a final blood sugar level, the photoacoustic signals being obtained from the tissue by emitting a pulse laser ray towards a second portion of the tissue before and after the applying of the pressure by the tissue modulation unit.

2. The apparatus of claim 1, wherein the tissue modulation unit applies a predetermined pressure between a contact instrument for contacting the tissue and a third portion of the tissue.

3. The apparatus of claim 1, wherein the tissue modulation unit comprises:

a pressure sensor of the contact instrument to contact the tissue, and sense the pressure applied to the third portion of the tissue; and

a pressure applier applying the pressure between the contact instrument and the third portion by using a result of the sensing which is fed back from the pressure sensor.

4. The apparatus of claim 1, wherein the tissue corresponds to a portion of a finger or a forearm.

5. The apparatus of claim 1, wherein the Hb concentration measurement unit comprises:

a light source array having a plurality of light sources generating the electromagnetic waves;

an optical sensor sensing the electromagnetic waves when the electromagnetic waves are generated from the plurality of light sources and pass through the first portion of the tissue; and

an Hb concentration calculator calculating an amount of absorption of electromagnetic waves on the first portion sensed by the optical sensor before and after the applying of the pressure, and calculating the Hb concentration.

6. The apparatus of claim 5, wherein the optical sensor is installed in a contact instrument for contacting the tissue.

7. The apparatus of claim 1, wherein the pulse laser ray has a wavelength of less than 850 nm.

8. The apparatus of claim 1, wherein the photoacoustic module unit corrects the measured blood sugar concentration based on a threshold value of the Hb concentration to calculate the final blood sugar level.

9. The apparatus of claim 1, wherein the photoacoustic module unit comprises:

a pulse laser diode (LD) light source unit generating a laser ray having a pulse wavelength, and emitting the laser ray towards the second portion of the tissue;

a photoacoustic signal detector detecting a photoacoustic signal generated from the second portion of the tissue after emitting the laser ray; and

a blood sugar concentration calculator measuring blood sugar concentration from the detected photoacoustic signal, and correcting the measured blood sugar concentration according to the Hb concentration measured by the Hb concentration measurement unit to calculate a final blood sugar level.

10. The apparatus of claim 9, further comprising:

a light collector collecting the laser ray, generated from the pulse LD light source unit, on the second portion of the tissue; and

an amplifier eliminating noise in the photoacoustic signal detected by the photoacoustic signal detector, and amplifying the photoacoustic signal in which the noise is eliminated.

11. The apparatus of claim 9, wherein the photoacoustic signal detector includes a piezoelectric (PZT) device.

18. The apparatus of claim 1, wherein light absorbed by the tissue is changed into elastic waves to generate the photoacoustic signals.

19. The apparatus of claim 1, wherein the photoacoustic signals include information about an optical characteristic, a thermal characteristic and an elastic characteristic of the tissue that absorbs the light.

12. A method of noninvasively measuring blood sugar concentration, the method comprising:

analyzing an amount of absorption of electromagnetic waves on a first portion of a tissue;

emitting a pulse laser ray towards a second portion of the tissue and analyzing a first photoacoustic signal generated from the second portion of the tissue;

applying a pressure to a third portion of the tissue;

analyzing an amount of absorption of electromagnetic waves on the first portion of the tissue after the applying of the pressure;

emitting the pulse laser ray towards the second portion of the tissue after the applying of the pressure, and analyzing a second photoacoustic signal generated from the second portion of the tissue;

calculating Hb concentration using a difference of the amount of absorption of electromagnetic waves on the first portion of the tissue before and after the applying of the pressure; and

measuring blood sugar concentration of the tissue using a difference between the first photoacoustic signal and the second photoacoustic signal, and calculating a corrected measured blood sugar concentration according to the calculated Hb concentration.

20. The method of claim 12, wherein the photoacoustic signals include information about an optical characteristic, a thermal characteristic and an elastic characteristic of the tissue that absorbs the light.

13. A computer-readable recording medium storing a program to implement a method of noninvasively measuring blood sugar concentration, the method comprising:

analyzing an amount of absorption of electromagnetic waves on a first portion of a tissue;

emitting a pulse laser ray towards a second portion of the tissue and analyzing a first photoacoustic signal generated from the second portion of the tissue;

applying a pressure to a third portion of the tissue;

analyzing an amount of absorption of electromagnetic waves on the first portion of the tissue after the applying of the pressure;

emitting the pulse laser ray towards the second portion of the tissue after the applying of the pressure, and analyzing a second photoacoustic signal generated from the second portion of the tissue;

calculating Hb concentration using a difference of the amount of absorption of electromagnetic waves on the first portion of the tissue before and after the applying of the pressure; and

measuring blood sugar concentration of the tissue using a difference between the first photoacoustic signal and the second photoacoustic signal, and calculating a corrected measured blood sugar concentration according to the calculated Hb concentration.

14. A computer-readable recording medium storing a program to implement a method of noninvasively measuring blood sugar concentration, the method comprising:

analyzing, upon a pressure being applied to a tissue, an amount of absorption of electromagnetic waves on a first portion of the tissue before and after the applying of the pressure by the tissue modulation unit, and measuring Hb concentration of the tissue; and

determining a final blood sugar level based on measured photoacoustic signals from the tissue, when a pulse laser ray is emitted towards a second portion of the tissue before and after the applying of the pressure, wherein the measured photoacoustic signals are utilized to determine a blood sugar concentration and to correct the measured blood sugar concentration based on the measured Hb concentration.

15. The computer-readable recording medium of claim 14, wherein measuring the Hb concentration of the tissue comprises:

obtaining signals from an optical sensor sensing the electromagnetic waves when the electromagnetic waves are generated from a plurality of light sources and pass through the first portion of the tissue; and

calculating an amount of absorption of electromagnetic waves on the first portion sensed by the optical sensor before and after the applying of the pressure, and calculating the Hb concentration.

16. The computer-readable recording medium of claim 14, wherein light absorbed by a receiving medium is changed into elastic waves to generate the photoacoustic signals.

17. The computer-readable recording medium of claim 14, wherein the measured photoacoustic signals include information about an optical characteristic, a thermal characteristic and an elastic characteristic of a receiving medium that absorbs the light.