Optical non-invasive blood monitoring system and method

• US 20090043178A1
• Filed: 09/20/2008
• Published: 02/12/2009
• Est. Priority Date: 07/25/2006
• Status: Active Grant

• Current Assignee: Edward Belotserkovsky
• Original Assignee: Edward Belotserkovsky
• Inventors: Belotserkovsky, Edward
• Granted Patent: US 8,326,390 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• 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 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

A simple noninvasive technique that is capable of very accurate and fast blood analyte, e.g., glucose, level monitoring is provided. Fluctuation in the levels of glucose and other analytes affect the refractive index of blood and extra cellular fluid in biological tissue. Given that the propagation speed of light through a medium depends on its refractive index, continuous monitoring of analyte levels in tissue is achieved by measuring characteristics of the tissue that can be correlated to the refractive index of the tissue. For instance, the frequency or number of optical pulse circulations that are transmitted through an individual'"'"'s tissue of known thickness within a certain time period can be correlated to an individual'"'"'s blood glucose level.

Claims

1. A device for noninvasive measurement of the levels of at least one analyte in a subject that comprises:

means for irradiating the subject through tissue with electromagnetic radiation;

means for detecting the radiation that passes through the tissue;

means for calculating the speed at which the electromagnetic radiation passes through the tissue;

means for monitoring at least one of back or forward scattering of electromagnetic radiation within the tissue; and

means for correlating the calculated speed of the electromagnetic radiation to the concentration of the at least one analyte in the subject.

2. The device of claim 1 comprising mean for monitoring of attenuation of electromagnetic radiation within the tissue

3. The device of claim 1 comprising means for monitoring both back and forward scatting of electromagnetic radiation within the tissue.

4. The device of claim 1 wherein the means for irradiating the subject emits pulses of radiation and the means for detecting the radiation measures the number of pulses of radiation that passes through the tissue during a defined time period which is referred as the pulse circulation frequency measurement.

5. The device of claim 4 wherein means for correlating the calculated speed of the electromagnetic radiation to the concentration of the at least one analyte in the subject calculates the changes, if any, of the pulse circulation frequency being measured.

6. The device of claim 1 wherein the means for irradiating the subject emits pulses of radiation and the means for detecting the radiation measures the time period required for a defined number of pulses of radiation to pass through the tissue which is referred to as the time interval measurement.

7. The device of claim 6 wherein means for correlating the calculated speed of the electromagnetic radiation to the concentration of the at least one analyte in the subject calculates the changes, if any, of the time interval being measured.

8. The device of claim 1 further comprising means for dispensing a medical formulation in response to a determination of the concentration of the at least one analyte in the subject.

9. The device of claim 1 wherein the at least one analyte is selected from the group consisting of glucose, cholesterol, triglycerides, urea, protein, and mixtures thereof.

10. The device of claim 1 wherein said at least one analyte is glucose.

11. The device of claim 1 wherein the concentration of two or more analytes are measured and the means for irradiating the subject emits electromagnetic radiation at two or more different wavelengths.

12. The device of claim 1 wherein the means for irradiating the subject through tissue with electromagnetic radiation at different wavelengths in order to compensate for variations in conditions other than the concentration of the analyte or analytes being measured.

13. The device of claim 1 wherein the means for irradiating the subject comprises means for supporting the device such that the electromagnetic radiation passes through a defined thickness of the tissue.

14. A device for noninvasive measurement of the levels of at least one analyte in a subject that comprises:

means for irradiating the subject through tissue with electromagnetic radiation;

means for detecting the radiation that passes through the tissue;

means for calculating the speed at which the electromagnetic radiation passes through the tissue; and

means for correlating the calculated speed of the electromagnetic radiation to the concentration of the at least one analyte in the subject, wherein the device defines a plurality of measuring channels and wherein the plurality of measuring channels are operated by a single electronic processing unit.

15. The device of claim 14 comprising a plurality of optical sources of electromagnetic radiation that irradiates the tissue.

16. The device of claim 14 comprising a plurality of detectors that detect radiation that is transmitted through the tissue.

17. The device of claim 14 wherein the electronic processing unit comprises a multiplexer and a demultiplexer.

18. The device of claim 14 comprising an optical combiner that combines signals from a plurality of optical sources and an optical splitter that delivers input radiation to a plurality of detectors.

19. The device of claim 14 wherein the measurement channels have physical paths of different lengths

20. The device of claim 14 comprises means for monitoring at least one of back or forward scattering radiation.

21. The device of claim 20 that comprises means for monitoring both of back and forward scattering radiation.

22. A device for noninvasive measurement of the levels of glucose in a subject that comprises:

means for irradiating the subject through tissue with electromagnetic radiation having a wavelength such that the speed of the electromagnetic radiation propagating through the tissue is sensitive to the glucose concentration in the tissue;

means for detecting the radiation that passes through the tissue;

means for calculating the speed at which the electromagnetic radiation passes through the tissue;

means for monitoring at least one of back or forward scattering of electromagnetic radiation within the tissue; and

means for correlating the calculated speed of the electromagnetic radiation to the concentration of glucose in the subject.

23. The device of claim 22 comprising means for monitoring of attenuation of electromagnetic radiation within the tissue.

24. The device of claim 22 wherein the means for irradiating the subject emits pulses of radiation and the means for detecting the radiation measures the number of pulses of radiation that passes through the tissue during a defined time period, which is referred as the pulse circulation frequency measurement.

25. The device of claim 24 wherein the means for correlating the calculated speed of the electromagnetic radiation to the concentration of the glucose in the subject calculates the changes, if any, of the pulse circulation frequency being measured.

26. The device of claim 22 wherein the means for irradiating the subject emits pulses of radiation and the means for detecting the radiation measures the time period required for a defined number of pulses of radiation to pass through the tissue which is referred to as the time interval measurement.

27. The device of claim 26 wherein the means for correlating the calculated speed of the electromagnetic radiation to the concentration of the at least one analyte in the subject calculates the changes, if any, of the time interval being measured.

28. The device of claim 22 further comprising means for dispensing an insulin formulation in response to a determination of the concentration of the glucose in the subject.

29. A device for noninvasive measurement of the levels of glucose in a subject that comprises:

means for irradiating the subject through tissue with electromagnetic radiation having a wavelength such that the speed of the electromagnetic radiation propagating through the tissue is sensitive to the glucose concentration in the tissue;

means for detecting the radiation that passes through the tissue;

means for calculating the speed at which the electromagnetic radiation passes through the tissue; and

means for correlating the calculated speed of the electromagnetic radiation to the concentration of glucose in the subject, wherein the device defines a plurality of measuring channels and wherein the plurality of measuring channels are operated by a single electronic processing unit.

30. The device of claim 29 comprising a plurality of optical sources of electromagnetic radiation that irradiates the tissue.

31. The device of claim 29 comprising a plurality of detectors that detect radiation that is transmitted through the tissue.

32. The device of claim 29 wherein the electronic processing unit comprises a multiplexer and a demultiplexer.

33. The device of claim 29 comprising an optical combiner that combines signals from a plurality of optical sources and an optical splitter that delivers input radiation into a plurality of detectors.

34. The device of claim 29 wherein the measurement channels have physical paths of different lengths.

35. The device of claim 29 comprises means for monitoring at least one of forward or back scattering radiation.

36. The device of claim 35 that comprises means for monitoring both of forward and back scattering radiation.

37. A noninvasive method of monitoring the levels of at least one analyte in a subject that comprises:

(a) irradiating the subject through tissue of known thickness with electromagnetic radiation;

(b) detecting the radiation that passes through the tissue;

(c) calculating the speed at which the electromagnetic radiation passed through the tissue; and

(d) correlating the calculated speed of the electromagnetic radiation to the concentration of the at least one analyte in the subject.

38. The method of claim 37 that further comprises monitoring attenuation of the radiation that passes through the tissue.

39. The method of claim 37 that further comprises monitoring at least one of back or forward scattering of electromagnetic radiation within the tissue.

40. The method of claim 37 that further comprises monitoring of both back and forward scattering of electromagnetic radiation within the tissue.

41. The method of claim 37 wherein step (a) comprises of directing pulses of radiation through the tissue and step (b) comprises of detecting the pulses that passes through the tissue during a defined time period, which is referred as the pulse circulation frequency measurement.

42. The method of claim 41 wherein step (d) comprises of calculating the changes, if any, of the pulse circulation frequency being measured.

43. The method of claim 37 wherein step (a) comprises of directing pulses of radiation and step (b) comprises of measuring the time period required for a defined number of pulses of radiation to pass through the tissue which is referred to as the time interval measurement.

44. The method of claim 43 wherein step (d) comprise of calculating the changes, if any, of the time interval being measured.

45. The method of claim 37 further comprising the step of dispensing a medical formulation in response to a determination of the concentration of the at least one analyte in the subject.

46. The method of claim 37 wherein the at least one analyte is selected from the group consisting of glucose, cholesterol, triglycerides, urea, protein, and mixtures thereof.

47. The method of claim 37 wherein said at least one analyte is glucose.

48. The method of claim 37 wherein the concentration of two or more analytes are measured and step (a) comprises of irradiating the subject with electromagnetic radiation at two or more different wavelengths.

49. The method of claim 37 wherein step (a) comprises of irradiating the subject through tissue with electromagnetic radiation at different wavelengths in order to compensate for variations in conditions other than the concentration of the analyte or analytes being measured.