Subsurface thermal gradient spectrometry

• US 6,049,081 A
• Filed: 06/08/1998
• Issued: 04/11/2000
• Est. Priority Date: 03/12/1997
• Status: Expired due to Fees

• Current Assignee: OptiScan Biomedical Corporation
• Original Assignee: OptiScan Biomedical Corporation
• Inventors: Kramer, Charles E., Braig, James R., Sterling, Bernhard B., Shulenberger, Arthur M., Goldberger, Daniel S., King, Richard A., Trebino, Rick
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US09/093,951
• Time in Patent Office: 673 Days
• Field of Search: 250/252.1 R, 250/339.03, 250/339.04, 250/339.05, 250/339.07, 250/339.09, 250/339.11, 250/252.1 A, 250/253, 250/341.1, 250/341.5 , 250/341.6, 250/341.8
• US Class Current: 250/339.03
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14539 for measuring pH
• 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 5/1491 Heated applicators
• CPC Class Codes: G01N 21/35 using infrared light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/71 thermally excited

Abstract

Spectrometric methodology for non-invasively obtaining optical spectra from heterogeneous material for the identification and quantification of constituent compounds. There is provided a transient or steady state subsurface thermal gradient spectroscopic methodology for obtaining in vivo optical spectra relating to the concentration of n analytes at depths to around 330 microns in human tissue, and for determining that concentration from the spectra. The methodology is employable on a wide variety of spectrometric devices, and enables: a real time determination of both surface and reference intensities; a fast, efficient calibration of the spectrometric device; and results in the provision of an analytical parameter which avoids the measurement of the optical path length to enable the extremely accurate calculation of a ratio of concentrations of n analytes in the system under analysis.

Claims

1. A method for spectroscopically analyzing a material utilizing a spectrometric instrument and a means for inducing a thermal gradient in said material, comprising the steps of:

(a) inducing said thermal gradient in said material;

(b) responsive to said inducing step, determining the surface emission from the material; and

(c) determining a parameter from said surface emission correlating to a property of said material independent of optical pathlength.

2. A method as recited in claim 1, further comprising the steps of:

(d) determining a reference intensity from said material; and

(e) determining said parameter correlating to a property of said material from said surface emission and said reference intensity.

3. A method as recited in claim 2, wherein said reference intensity is determined utilizing said spectrometric instrument.

4. A method as recited in claim 1, further comprising the step of calibrating said instrument prior to said inducing step.

5. A method as recited in claim 1, further comprising the step of transmitting said parameter correlating to a property of said material as an electrical signal for further processing.

6. A method for spectroscopically analyzing a material utilizing a spectrometric instrument and a means for inducing a thermal gradient in said material, comprising the steps of:

(a) determining a reference intensity from said material; and

(b) inducing said thermal gradient in said material;

(c) responsive to said inducing step, determining the surface emission from the material; and

(d) determining a parameter correlating to a property of said material from said surface emission and said reference intensity.

7. A method as recited in claim 6, wherein said reference intensity is determined utilizing said spectrometric instrument.

8. A method as recited in claim 6, wherein said parameter correlating to a property of said material is determined independent of optical pathlength.

9. A method as recited in claim 6, further comprising the step of calibrating said instrument prior to said inducing step.

10. A method as recited in claim 6, further comprising the step of transmitting said parameter correlating to a property of said material as an electrical signal for further processing.

11. A method for spectroscopically analyzing a material utilizing a spectrometric instrument and a means for inducing a thermal gradient in said material, comprising the steps of:

(a) determining a reference intensity from said material utilizing said spectrometric instrument;

(b) inducing said thermal gradient in said material;

(c) responsive to said inducing step, determining the surface emission from the material; and

(d) determining a parameter correlating to a property of said material from said surface emission and said reference intensity.

12. A method as recited in claim 11, wherein said parameter correlating to a property of said material is determined independent of optical pathlength.

13. A method as recited in claim 11, further comprising the step of calibrating said instrument prior to said inducing step.

14. A method as recited in claim 11, further comprising the step of transmitting said parameter correlating to a property of said material as an electrical signal for further processing.

15. A method for spectroscopically analyzing a material utilizing a spectrometric instrument and a means for inducing a thermal gradient in said material, comprising the steps of:

(a) calibrating said spectrometric instrument;

(b) inducing said thermal gradient in said material;

(c) responsive to said inducing step, determining the surface emission from the material; and

(d) determining a parameter from said surface emission correlating to a property of said material.

16. A method as recited in claim 15, wherein said parameter correlating to a property of said material is determined independent of optical pathlength.

17. A method as recited in claim 15, further comprising the steps of:

(e) determining a reference intensity from said material; and

(f) determining said parameter correlating to a property of said material from said surface emission and said reference intensity.

18. A method as recited in claim 17, wherein said reference intensity is determined utilizing said spectrometric instrument.

19. A method as recited in claim 15, further comprising the step of transmitting said parameter correlating to a property of said material as an electrical signal for further processing.

20. A method for spectroscopically analyzing a material utilizing a spectrometric instrument and a means for inducing a thermal gradient in said material, comprising the steps of:

(a) inducing said thermal gradient in said material;

(b) responsive to said inducing step, determining the surface emission from the material;

(c) determining a parameter from said surface emission correlating to a property of said material; and

(d) transmitting said parameter as an electrical signal for further processing.

21. A method as recited in claim 20, wherein said parameter correlating to a property of said material is determined independent of optical pathlength.

22. A method as recited in claim 20, further comprising the steps of:

(e) determining a reference intensity from said material; and

(f) determining said parameter correlating to a property of said material from said surface emission and said reference intensity.

23. A method as recited in claim 22, wherein said reference intensity is determined utilizing said spectrometric instrument.

24. A method as recited in claim 20, further comprising the step of calibrating said instrument prior to said inducing step.