Methods for noninvasive analyte sensing

• US 6,725,073 B1
• Filed: 07/17/2002
• Issued: 04/20/2004
• Est. Priority Date: 08/17/1999
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Esenaliev, Rinat O., Motamedi, Massoud
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US10/197,655
• Time in Patent Office: 643 Days
• Field of Search: 600/309-310, 600/365, 600/316, 600/322
• US Class Current: 600/316
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• 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: G01B 2290/70 Using polarization in the interferometer
• CPC Class Codes: G01B 9/02007 Two or more frequencies or sources used for interferometric measurement using only beat G01B9/02003
• CPC Class Codes: G01B 9/02087 Combining two or more images of the same region
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

Methods for measuring analyte concentration within a tissue using optical coherence tomography (OCT). Radiation is generated, and a first portion of the radiation is directed to the tissue to generate backscattered radiation. A second portion of the radiation is directed to a reflector to generate reference radiation. The backscattered radiation and the reference radiation is detected to produce an interference signal. The analyte concentration is calculated using the interference signal.

Claims

1. A method for measuring glucose concentration within a tissue, comprising:

generating radiation;

directing a first portion of the radiation to the tissue to generate backscattered radiation;

directing a second portion of the radiation to a reflector to generate reference radiation;

detecting the backscattered radiation and the reference radiation to produce an optical coherence tomography signal; and

calculating the glucose concentration using a slope of the optical coherence tomography signal.

2. The method of claim 1, wherein generating radiation comprises generating low-coherence radiation.

3. The method of claim 2, wherein generating low-coherence radiation comprises generating low-coherence radiation using a super-luminescent diode.

4. The method of claim 1, wherein generating radiation comprises generating radiation from a plurality of sources.

5. The method of claim 4, wherein two or more of the sources emit radiation having different wavelengths.

6. The method of claim 1, wherein a wavelength of the backscattered radiation is substantially equal to a wavelength of the reference radiation.

7. The method of claim 1, wherein the radiation has a first polarization and the backscattered radiation has a second polarization, the second polarization being different from the first polarization.

8. The method of claim 1, wherein the tissue comprises skin.

9. The method of claim 1, wherein the tissue comprises a blood vessel.

10. The method of claim 1, wherein the tissue comprises sclera.

11. The method of claim 1, wherein the tissue comprises lip.

12. The method of claim 1, wherein the tissue comprises tongue.

13. The method of claim 1, wherein the tissue comprises oral tissue.

14. The method of claim 1, wherein the tissue comprises ear.

15. The method of claim 1, wherein the backscattered radiation emanates from a tissue depth of between about 150 μ

m and about 500 μ

m.

16. The method of claim 1, wherein the backscattered radiation emanates from a tissue depth of between about 150 μ

m and about 400 μ

m.

17. The method of claim 1, wherein the backscattered radiation emanates from a tissue depth of between about 150 μ

m and about 200 μ

m.

18. The method of claim 1, wherein directing the first portion of the radiation comprises scanning the first portion of the radiation across a specified portion of the tissue.

19. The method of claim 1, wherein the calculating comprises determining a glucose-induced change in an optical property of the tissue.

20. The method of claim 19, wherein the optical property comprises scattering, anisotropic factors, absorption, or index of refraction.

21. The method of claim 1, wherein the calculating comprises determining a glucose-induced change in morphology of the tissue.

22. The method of claim 21, wherein the morphology comprises thickness or shape.

23. A method for measuring glucose concentration within a tissue, comprising:

detecting radiation backscattered from the tissue and reference radiation to generate an optical coherence tomography (OCT) signal; and

determining the glucose concentration within the tissue using a slope of the OCT signal.

24. The method of claim 23, wherein a wavelength of the radiation backscattered from the tissue is substantially equal to a wavelength of the reference radiation.

25. The method of claim 23, wherein the tissue comprises skin.

26. The method of claim 23, wherein the tissue comprises a blood vessel.

27. The method of claim 23, wherein the tissue comprises sclera.

28. The method of claim 23, wherein the tissue comprises lip.

29. The method of claim 23, wherein the tissue comprises tongue.

30. The method of claim 23, wherein the tissue comprises oral tissue.

31. The method of claim 23, wherein the tissue comprises ear.

32. The method of claim 23, wherein the radiation backscattered from the tissue emanates from a tissue depth of between about 150 μ

m and about 500 μ

m.

33. The method of claim 23, wherein the radiation backscattered from the tissue emanates from a tissue depth of between about 150 μ

m and about 400 μ

m.

34. The method of claim 23, wherein the radiation backscattered from the tissue emanates from a tissue depth of between about 150 μ

m and about 200 μ

m.

35. The method of claim 23, wherein using the slope comprises correlating the slope with an optical property of the tissue.

36. The method of claim 23, wherein using the slope comprises correlating the slope with a morphological property of the tissue.

37. The method of claim 23, wherein using the slope comprises correlating a percentage change in the slope with a change in glucose concentration.

38. A method for measuring analyte concentration within a tissue, comprising:

implanting a probe within the tissue, the probe configured to alter an optical coherence tomography (OCT) signal of the tissue;

generating an OCT signal of the tissue, the OCT signal being altered by the probe; and

correlating a change in slope of the OCT signal with the analyte concentration within the tissue.

39. The method of claim 38, wherein the analyte concentration comprises glucose concentration.

40. The method of claim 38, wherein the probe is configured to increase a sensitivity of the OCT signal.

41. The method of claim 38, wherein the tissue comprises skin.

42. A computer readable media containing program instructions for measuring glucose concentration within a tissue, the computer readable media comprising:

instructions for storing an optical coherence tomography (OCT) signal in memory; and

instructions for determining the glucose concentration within the tissue using the signal,

wherein the instructions for determining the glucose concentration comprise;

determining a slope of the OCT signal; and

determining the glucose concentration using the slope.

43. A computer readable media containing program instructions for measuring glucose concentration within a tissue, the computer readable media comprising:

instructions for storing an optical coherence tomography (OCT) signal in memory; and

instructions for determining the glucose concentration within the tissue using the signal,

wherein the instructions for determining the glucose concentration comprise;

instructions for correlating a change in the slope with an optical or morphological change in the tissue.

44. A method for measuring glucose concentration within a tissue, comprising:

generating radiation;

directing a first portion of the radiation to the tissue to generate backscattered radiation;

directing a second portion of the radiation to a reflector to generate reference radiation;

detecting the backscattered radiation and the reference radiation across a surface and in a depth to produce a two-dimensional image;

processing the two-dimensional image into a one-dimensional signal; and

calculating the glucose concentration using a slope of the one-dimensional signal.