NONINVASIVE, ACCURATE GLUCOSE MONITORING WITH OCT BY USING TISSUE WARMING AND TEMPERATURE CONTROL

• US 20070232873A1
• Filed: 03/13/2007
• Published: 10/04/2007
• Est. Priority Date: 03/16/2006
• Status: Abandoned Application

• 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, Prough, Donald
• Application Number:
  US11/685,677
• Publication Number:
  US 20070232873A1
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 5/0053 by applying pressure, e.g. compression, indentation, palpation, grasping, gauging
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement

Abstract

A new OCT system and method are disclosed, where the system includes a probe equipped with a heating element and a high heat conductive member to warm a tissue site to be scanned to an elevated and/or to maintain the elevated tissue temperature with a temperature variation of less than or equal to 1° C. to improve an accuracy and reliability of an OCT glucose concentration value other long measurement durations. The new OCT system and method can also be equipped with pressure components to reduce a pressure exerted on the tissue site to a minimal constant pressure.

Claims

1. A method comprising the steps of:

generating radiation;

directing a first portion of radiation onto a location of a tissue site or a plurality of locations of a tissue site to generate backscattered radiation corresponding to a plurality of 1-D OCT signals on an intermittent, a continuous or a periodic basis under conditions of temperature and/or pressure sufficient to increase an accuracy of a calculated glucose concentration,

directing a second portion of the radiation to a reflector to generate reference radiation on a continuous or periodic basis,

combining a portion of the backscattered radiation and the reference radiation to form a combined radiation on a continuous or periodic basis,

forwarding the combined radiation to a detector to produce a plurality of optical coherence tomography signals on a continuous or periodic basis, and

calculating the glucose concentration using a single slope or a composite slope of the optical coherence tomography signals on a continuous or periodic basis,

where the number of the plurality of signals is sufficient to improve the signal-to-noise ratio of a composite OCT signal improving the OCT derived glucose concentration.

2. The method of claim 1, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration.

3. The method of claim 2, wherein the temperature variation is less than about 1°

C.

4. The method of claim 2, further comprising the step of:

heating the tissue site to an elevated temperature, while maintaining the temperature at the elevated temperature so that the temperature variation is less than or equal 1°

C.

5. The method of claim 4, wherein the elevated temperature is between about 33°

C. and 45°

C.

6. The method of claim 1, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a pressure exerted on the tissue site to a minimal constant pressure sufficient to increase an accuracy of a calculated glucose concentration.

7. The method of claim 6, wherein the minimal constant pressure is less than about 0.1 kPa.

8. The method of claim 6, wherein the minimal constant pressure is less than about 0.01 kPa.

9. The method of claim 1, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration, and

maintaining a pressure exerted on the tissue site to a minimal constant pressure sufficient to increase an accuracy of a calculated glucose concentration.

10. The method of claim 9, wherein the temperature variation is less than about 1°

C. and the minimal constant pressure is less than about 0.1 kPa.

11. The method of claim 1, wherein the conditions of temperature and/or pressure comprise the step of:

heating the tissue site to an elevated temperature, while maintaining the tissue temperature at the elevated temperature so that a temperature variation is sufficient to increase an accuracy of a calculated glucose concentration, and

maintaining a pressure exerted on the tissue site to a minimal constant pressure is sufficient to increase an accuracy of a calculated glucose concentration.

12. The method of claim 11, wherein the elevated temperature is between about 33°

C. and 45°

C., the temperature variation is less than about 1°

C. and the minimal constant pressure is less than about 0.1 kPa.

13. The method of claim 1, wherein the locations are within an area, where the area is regular or irregular and is between about 200 μ

m×

200 μ

m and about 2000 μ

m×

2000 μ

m.

14. The method of claim 13, wherein the plurality of locations comprise the entire area, a random selection of locations within the area, a patterned selection of locations within the area, a random selection of contiguous sub-areas within the area, or a patterned selection of contiguous sub-areas within the area.

15. The method of claim 1, wherein a distance between pairs of locations is between about 500 nm and 20 mm.

16. The method of claim 1, wherein each scan is an in-depth scan.

17. The method of claim 16, further comprising the step of:

constructing 2-D images of each location.

18. The method of claim 17, further comprising the step of:

constructing a 3-D image of the area from the 2-D images at each location.

19. The method of claim 1, wherein each scan is at a set tissue depth or the scans have variable tissue depths.

20. The method of claim 1, further comprising the step of:

maintaining a pressure exerted on the tissue site by an OCT probe to a minimal constant pressure sufficient to improve the accuracy of the calculated glucose concentration.

47. The method of claim 1, further comprising the step of:

prior to the calculating step, filtering the OCT data with a filtering routine to produce filtered OCT data.

21. A method comprising the steps of:

generating first radiation having a first wavelength;

directing a first portion of first radiation onto a plurality of locations of an area of a tissue site to generate first backscattered radiation corresponding to a plurality of 1-D OCT signals on a continuous or periodic basis under conditions of temperature and/or pressure sufficient to increase an accuracy of a calculated glucose concentration,

directing a second portion of the first radiation to a reflector to generate first reference radiation on a continuous or periodic basis,

combining a portion of the first backscattered radiation and the first reference radiation to form a first combined radiation on a continuous or periodic basis,

forwarding the first combined radiation to a detector to produce a plurality of first optical coherence tomography signals on a continuous or periodic basis,

generating second radiation having a second wavelength;

directing a second portion of second radiation onto a plurality of locations of an area of a tissue site to generate second back scattered radiation corresponding to a plurality of 1-D OCT signals on a continuous or periodic basis under conditions of temperature and/or pressure sufficient to increase an accuracy of a calculated glucose concentration,

directing a second portion of the second radiation to a reflector to generate second reference radiation on a continuous or periodic basis,

combining a portion of the second backscattered radiation and the second reference radiation to form a second combined radiation on a continuous or periodic basis,

forwarding the second combined radiation to a detector to produce a plurality of second optical coherence tomography signals on a continuous or periodic basis, and

calculating a glucose concentration using data from a first composite OCT signal and a second OCT signal on a continuous or periodic basis,

where the number of the plurality of signals is sufficient to improve the signal-to-noise ratio of a composite OCT signal improving the OCT derived glucose concentration, where the first radiation is adapted to produce a high contrast OCT signal, where the second radiation is adapted to produce a water signal, and where data from the second radiation is used to reduce water artifacts during the calculating glucose concentration step.

22. The method of claim 21, wherein the first wavelength is between about 700 nm and about 1300 nm and the second wavelength is between about 1300 nm and about 2000 nm.

23. The method of claim 21, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration.

24. The method of claim 23, wherein the temperature variation is less than about 1°

C.

25. The method of claim 23, further comprising the step of:

heating the tissue site to an elevated temperature, while maintaining the temperature at the elevated temperature so that the temperature variation is less than or equal 1°

C.

26. The method of claim 25, wherein the elevated temperature is between about 33°

C. and 45°

C. and the temperature variation is less than about 1°

C.

27. The method of claim 21, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a pressure exerted on the tissue site to a minimal constant pressure sufficient to increase an accuracy of a calculated glucose concentration.

28. The method of claim 27, wherein the minimal constant pressure is less than 0.1 kPa.

29. The method of claim 27, wherein the minimal constant pressure is less than 0.01 kPa.

30. The method of claim 21, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration, and

maintaining a pressure exerted on the tissue site to a minimal constant pressure sufficient to increase an accuracy of a calculated glucose concentration.

31. The method of claim 30, wherein the temperature variation is less than 1°

C. and the minimal constant pressure is less than 0.1 kPa.

32. The method of claim 21, wherein the conditions of temperature and/or pressure comprise the step of:

heating the tissue site to an elevated temperature, while maintaining the tissue temperature at the elevated temperature so that a temperature variation is sufficient to increase an accuracy of a calculated glucose concentration, and

maintaining a pressure exerted on the tissue site to a minimal constant pressure is sufficient to increase an accuracy of a calculated glucose concentration.

33. The method of claim 32, wherein the elevated temperature is between about 33°

C. and 45°

C., the temperature variation is less than about 1°

C. and the minimal constant pressure is less than about 0.1 kPa.

48. The method of claim 21, further comprising the step of:

prior to the calculating step, filtering the OCT data with a filtering routine to produce filtered OCT data.

34. A method comprising the steps of:

generating radiation having a first wavelength and a second wavelength;

directing a first portion of radiation onto a plurality of locations of an area of a tissue site to generate backscattered radiation corresponding to a plurality of 1-D OCT signals on a continuous or periodic basis, while maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration,

directing a second portion of the radiation to a reflector to generate first reference radiation on a continuous or periodic basis,

combining a portion of the backscattered radiation and the reference radiation to form a first combined radiation on a continuous or periodic basis,

forwarding the combined radiation to a detector to produce a plurality of optical coherence tomography signals on a continuous or periodic basis,

calculating a glucose concentration using data from a first composite OCT signal and a second OCT signal on a continuous or periodic basis,

where the number of the plurality of signals is sufficient to improve the signal-to-noise ratio of a composite OCT signal improving the OCT derived glucose concentration, where the first radiation is adapted to produce a high contrast OCT signal, where the second radiation is adapted to produce a water signal, and where data from the second radiation is used to reduce water artifacts during the calculating glucose concentration step.

35. The method of claim 34, where in the first wavelength is between about 700 nm and about 1300 nm and the second wavelength is between about 1300 nm and about 2000 nm.

36. The method of claim 34, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration.

37. The method of claim 36, wherein the temperature variation is less than about 1°

C.

38. The method of claim 36, further comprising the step of:

heating the tissue site to an elevated temperature, while maintaining the temperature at the elevated temperature so that the temperature variation is less than or equal 1°

C.

39. The method of claim 38, wherein the elevated temperature is between about 33°

C. and 45°

C. and the temperature variation is less than about 1°

C.

40. The method of claim 34, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a pressure exerted on the tissue site to a minimal constant pressure sufficient to increase an accuracy of a calculated glucose concentration.

41. The method of claim 40, wherein the minimal constant pressure is less than about 0.1 kPa.

42. The method of claim 49, wherein the minimal constant pressure is less than about 0.01 kPa.

43. The method of claim 35, wherein the conditions of temperature and/or pressure comprise the step of:

maintaining a temperature of the tissue site to a temperature variation sufficient to increase an accuracy of a calculated glucose concentration, and maintaining a pressure exerted on the tissue site to a minimal constant pressure sufficient to increase an accuracy of a calculated glucose concentration.

44. The method of claim 43, wherein the temperature variation is less than about 1°

C. and the minimal constant pressure is less than about 0.1 kPa.

45. The method of claim 35, wherein the conditions of temperature and/or pressure comprise the step of:

heating the tissue site to an elevated temperature, while maintaining the tissue temperature at the elevated temperature so that a temperature variation is sufficient to increase an accuracy of a calculated glucose concentration, and

maintaining a pressure exerted on the tissue site to a minimal constant pressure is sufficient to increase an accuracy of a calculated glucose concentration.

46. The method of claim 44, wherein the elevated temperature is between about 33°

C. and 45°

C., the temperature variation is less than about 1°

C. and the minimal constant pressure is less than about 0.1 kPa.

49. The method of claim 34, further comprising the step of:

prior to the calculating step, filtering the OCT data with a filtering routine to produce filtered OCT data.