Identifying or measuring selected substances or toxins in a subject using resonant raman signals

• US 20040127778A1
• Filed: 03/25/2003
• Published: 07/01/2004
• Est. Priority Date: 01/09/2001
• Status: Active Grant

• Current Assignee: California Institute of Technology, Childrens Hospital Los Angeles
• Original Assignee: California Institute of Technology, Childrens Hospital Los Angeles
• Inventors: Borchert, Mark S., Lambert, James L.
• Granted Patent: US 6,961,599 B2
• Time in Patent Office: Days
• US Class Current: 600/318
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/4064 Evaluating the brain A61B5/031, A61B5/369, A61B5/14553 take precedence
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61B 5/6821 Eye
• CPC Class Codes: G01N 2021/656 Raman microprobe
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

Methods and systems of the present invention identify the presence of and/or the concentration of a selected analyte in a subject by: (a) illuminating a selected region of the eye of a subject with an optical excitation beam, wherein the excitation beam wavelength is selected to generate a resonant Raman spectrum of the selected analyte with a signal strength that is at least 100 times greater than Raman spectrums generated by non-resonant wavelengths and/or relative to signals of normal constituents present in the selected region of the eye; (b) detecting a resonant Raman spectrum corresponding to the selected illuminated region of the eye; and (c) identifying the presence, absence and/or the concentration of the selected analyte in the subject based on said detecting step. The apparatus may also be configured to be able to obtain biometric data of the eye to identify (confirm the identity of) the subject.

Claims

1. A non-invasive method for identifying the presence of and/or the concentration of a selected analyte in a subject, comprising:

illuminating a selected region in the eye of a subject with an optical excitation beam, wherein the excitation beam wavelength is selected to generate a resonant Raman spectrum of the selected analyte;

detecting a resonant Raman spectrum corresponding to the selected illuminated region of the eye; and

identifying the presence, absence and/or the concentration of the selected analyte in the subject based on said detecting step.

2. A method according to claim 1, wherein the wavelength is between about 400 nm-600 nm.

3. A method according to claim 1, wherein the selected analyte is a chemotherapeutic agent.

4. A method according to claim 1, wherein the selected analyte is an antifungal agent.

5. A method according to claim 1, wherein the selected analyte has a chemical structure having at least one of a carbon-carbon bond and/or a carbon double bond, the method further comprising monitoring at least one peak of interest in the detected Raman spectrum associated with the carbon-carbon bond and/or the double carbon bond of the selected analyte chemical structure.

6. A method according to claim 1, wherein the selected analyte has a chemical structure having a carbon double bond, the method further comprising monitoring the detected Raman spectrum associated with the carbon double bond of the selected analyte chemical structure, and wherein the excitation wavelength is between about 400-514 nm.

7. A method according to claim 1, wherein the excitation wavelength is between about 400-408 nm.

8. A method according to claim 6, wherein the selected analyte comprises amphotercin B or a substantial chemical equivalent, and/or metabolites, constituents or derivatives thereof.

9. A method according to claim 6, wherein the selected analyte comprises fenretinide or a substantial chemical equivalent, and/or metabolites, constituents or derivatives thereof.

10. A method according to claim 1, further comprising:

comparing the Raman spectrum from said detecting step to a priori reference spectra corresponding to different concentrations of a plurality of different concentrations of the selected analyte.

11. A method according to claim 1, wherein the selected analyte comprises at least one selected drug, pharmaceutical agent, metabolite, derivative or constituent thereof, and wherein the step of identifying determines a concentration level in the micromolar range in the selected region of the eye.

12. A method according to claim 1, wherein the selected analyte comprises at least one selected drug, pharmaceutical agent, metabolite, derivative or constituent thereof, and wherein the step of identifying determines a concentration level in the nanomolar range in the selected region of the eye.

13. A method according to claim 1, wherein the detecting step is carried out to obtain a first resonant Raman spectrum of the subject before administering a selected treatment and then to obtain a second resonant spectrum after administration of the selected treatment, and wherein the identifying step comprises subtracting baseline signatures of data from the second resonant Raman spectrum using data from the first resonant Raman spectrum.

14. A method according to claim 1, wherein the identifying step comprises analyzing selected Raman spectra residing within 700-1700 cm⁻

1 of the resonant Raman spectrum to determine the presence and/or concentration of the selected analyte.

15. A method according to claim 14, wherein a plurality of selected narrow regions in the resonant Raman spectrum are analyzed to determine the concentration of the analyte in the subject.

16. A method according to claim 1, wherein the blood level concentration is determined.

17. A method according to claim 1, wherein the brain or cerebral spinal fluid concentration is determined.

18. An evaluation apparatus for identifying the presence and/or concentration of a selected analyte in a subject subject, comprising:

means for illuminating a selected region of the eye with an optical excitation beam, wherein the optical excitation beam has a wavelength that is at least about 400 nm, resides within the absorption spectrum, and that generates a resonant Raman spectrum of a selected analyte in a subject;

means for focusing the excitation beam into a selected region in the eye of the subject so that the selected region is illuminated;

means for detecting a resonant Raman spectrum corresponding to the illuminated selected region of the eye; and

means for identifying the presence and/or concentration of the selected analyte in the subject responsive to the detecting means.

19. An apparatus according to claim 18, wherein the means for identifying includes computer program code that determines the concentration level of the selected analyte using statistical analytical partial least squares.

20. An apparatus according to claim 18, wherein the means for identifying includes computer program code that determines the concentration level of the selected analyte using statistical analytical hybrid linear analysis.

21. An apparatus according to claim 18, wherein the apparatus is configured to detect micromolar ranges of concentrations of the selected analyte in the eye.

22. An apparatus according to claim 18, wherein the apparatus is configured to detect nanomolar ranges of concentrations of the selected analyte in the eye.

23. An apparatus according to claim 18, wherein the apparatus is configured to detect blood concentrations.

24. An apparatus according to claim 18, wherein the apparatus is configured to detect brain, intracranial, and/or cerebral spinal fluid level concentrations.

25. An apparatus according to claim 18, wherein the selected analyte is a pharmaceutical agent.

26. An apparatus according to claim 18, wherein the means for providing is configured to generate an excitation signal wavelength that is between about 400 nm-600 nm.

27. An apparatus according to claim 26, wherein the excitation wavelength is between about 400-514 nm.

28. An apparatus according to claim 27, wherein the excitation wavelength is between about 400-408 nm.

29. An apparatus according to claim 18, wherein the selected analyte is a chemotherapeutic agent.

30. An apparatus according to claim 18, wherein the selected analyte is an antifungal agent.

31. An apparatus according to claim 18, wherein the selected analyte has a chemical structure having at least one of a carbon-carbon bond and/or a carbon double bond, the apparatus comprising computer program code for analyzing at least one peak of interest in the detected resonant Raman spectrum associated with the carbon-carbon bond and/or the carbon double bond of the selected analyte chemical structure.

32. An apparatus according to claim 18, wherein the selected analyte comprises amphotercin B or a substantial chemical equivalent and/or metabolites, constituents, or derivatives thereof.

33. An apparatus according to claim 18, wherein the selected analyte comprises fenretinide or a substantial chemical equivalent and/or metabolites, constituents, or derivatives thereof.

34. An apparatus according to claim 18, wherein the means for identifying includes computer program code for comparing the resonant Raman spectrum to a priori reference spectra corresponding to different concentrations of a plurality of different concentrations of the selected analyte.

35. An apparatus according to claim 18, wherein the means for identifying comprises computer program code that compares a first resonant Raman spectrum of the subject taken before administering a selected treatment to a second resonant Raman spectrum taken after administration of the selected treatment, and subtracts baseline signature data from the second resonant Raman spectrum using data from the first resonant Raman spectrum.

36. An apparatus according to claim 18, wherein the means for identifying comprises computer program code for analyzing selected Raman spectra residing within 700-1700 cm⁻

1 of the resonant Raman spectrum to determine the presence and/or concentration of the selected analyte.

37. An apparatus according to claim 18, wherein the means for identifying comprises computer program code that analyzes a plurality of selected narrow regions in the resonant Raman spectrum to determine the concentration of the analyte in the subject.

38. An apparatus according to claim 18, wherein the means for illuminating is configured to confocally deliver the excitation beam to the aqueous humor of the eye of the subject.

39. An apparatus according to claim 18, wherein said means for identifying comprises computer program code for sampling selected wave numbers of the resonant Raman spectrum using a partial least squares statistical model.

40. An apparatus according to claim 18, wherein said means for identifying comprises computer program code for sampling selected wave numbers of the resonant Raman spectrum using a hybrid linear analysis statistical model.

41. An apparatus according to claim 34, wherein the reference spectra comprise a plurality of different resonant Raman spectra generated for the selected analyte at different concentrations based on in vitro samples thereof.

42. An apparatus according to claim 18, wherein said excitation beam has a power rating of about 2 mW that illuminates for about 10 seconds.

43. An apparatus according to claim 18, wherein the means for identifying comprises computer program code that subtracts a fluorescence spectrum from the resonant Raman spectrum to produce a difference spectrum.

44. An apparatus according to claim 18, wherein the apparatus is configured to detect a plurality of different selected analytes of interest.

45. An apparatus according to claim 44, further comprising computer program code of reference data of spectra for each analyte of interest comprising spectra generated from a Raman spectra training set based on at least 10 in vitro aqueous humor samples for each analyte of interest with each of the at least 10 samples including different amounts of the analyte therein, and an analyte level corresponding to each of the samples.

46. An apparatus according to claim 45, wherein the computer program reference data are generated from a training set of Raman spectra corresponding to at least 20 aqueous humor samples of varying concentrations of analytes therein for each of a plurality of different selected analytes and an identified blood level, and brain or cerebral spinal fluid level of said analyte of interest for each of said samples.

47. An apparatus according to claim 18, wherein said apparatus comprises a portable housing that holds the components therein, and wherein the housing includes a user interface that is configured and sized to fit onto and/or rest against the head of the subject during operation.

48. An apparatus according to claim 47, wherein said housing is configured and sized to be a hand held device.

49. A non-invasive method for identifying the presence and/or the concentration of a selected analyte in a subject and identifying the subject, comprising:

illuminating a selected region in the eye of a subject with an optical excitation beam;

detecting a response spectrum corresponding to the selected illuminated region of the eye;

determining the presence, absence and/or the concentration of the selected analyte in the subject based on said detecting step;

obtaining a biometric reading of the iris or retinal structure; and

identifying the subject based on the biometric reading.

50. A non-invasive method according to claim 49, wherein the obtaining step is carried out by obtaining an image of the iris and comparing the image to predetermined iris characteristics, and wherein the detected spectrum is a Raman spectrum.

51. An apparatus for determining the presence of and/or the concentration of a selected analyte in a subject and confirming the identity the subject, comprising:

means for illuminating a selected region of the eye of a subject with an optical excitation beam so that the selected region is illuminated;

means for detecting a response spectrum corresponding to the selected illuminated region of the eye;

means for determining the presence and/or the concentration of the selected analyte in the subject responsive to said means for detecting; and

means for obtaining a biometric reading of the iris or retinal structure to identify the subject.