METHOD AND APPARATUS FOR MEASUREMENT OF OPTICAL PROPERTIES IN TISSUE

• US 20070203404A1
• Filed: 01/31/2007
• Published: 08/30/2007
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Sampson, David, Leigh, Matthew, Zysk, Adam, Armstrong, Julian, Boppart, Stephen, Adie, Steven
• Granted Patent: US 7,787,129 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 10/0233 Pointed or sharp biopsy instruments
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0091 for mammography
• CPC Class Codes: A61B 5/6848 Needles

Abstract

A method of analyzing tissue includes inserting a radiation source into tissue, impinging radiation upon the tissue, obtaining a sample signal of the radiation that impinges upon the tissue, and determining a refractive index of the tissue from the sample signal. The method may also include determining at least one other optical property of the tissue. The method may provide for identifying tissue as part of a biopsy method. A device for analyzing tissue may include a low-coherence interferometer and a probe optically coupled to the interferometer, where the probe includes a radiation source.

Claims

1. A method of analyzing tissue, comprising:

inserting a radiation source into tissue;

impinging radiation upon the tissue;

obtaining a sample signal of the radiation from the tissue; and

determining a refractive index of the tissue from the sample signal.

2. The method of claim 1, further comprising determining at least one other optical property of the tissue.

3. The method of claim 2, where the at least one other optical property is selected from the group consisting of the attenuation coefficient, the scattering profile, the anisotropy factor, the birefringence, the spectral shift, and the texture.

4. The method of claim 1, where the impinging radiation comprises passing low-coherence radiation through an optical fiber to the tissue;

and the determining comprises combining the sample signal with a reference signal to produce an interferogram.

5. The method of claim 1, where the inserting a radiation source comprises inserting a probe into the tissue, where the probe includes a radiation source.

6. The method of claim 5, where the radiation source comprises a first optical fiber having a first exposed end.

7. The method of claim 6, where the obtaining the sample signal comprises collecting radiation that has been scattered or reflected from the tissue;

and the determining comprises comparing the known distance between two foci in a reference medium and a measured pathlength between the two foci in the tissue.

8. The method of claim 6, where the probe further includes a reflective surface and a gap between the reflective surface and the first exposed end;

where the obtaining the sample signal comprises collecting radiation that has been reflected from the reflective surface to the first exposed end; and

the determining comprises comparing the physical distance from the first exposed end to the reflective surface and a measured pathlength from the first exposed end to the reflective surface.

9. The method of claim 6, where the probe further includes a second optical fiber having a second exposed end, and a gap between the first exposed end and the second exposed end;

where the obtaining the sample signal comprises collecting radiation that has been transmitted through the tissue from the first exposed end to the second exposed end; and

the determining comprises comparing the physical distance from the first exposed end to the second exposed end and a measured pathlength from the first exposed end to the second exposed end.

10. A method of identifying tissue, comprising:

impinging radiation upon tissue;

obtaining a sample signal of the radiation from the tissue;

determining a refractive index of the tissue from the sample signal; and

identifying the tissue by the refractive index.

11. The method of claim 10, further comprising inserting a radiation source into the tissue prior to impinging radiation upon the tissue.

12. The method of claim 10, where the tissue is a tumor.

13. The method of claim 10, further comprising determining at least one other optical property of the tissue, and

identifying the tissue by the refractive index and the at least one other optical property.

14. The method of claim 13, where the tissue is a tumor.

15. A method of performing a biopsy of tissue, comprising:

identifying tissue according to the method of claim 10;

and

biopsying at least a portion of the tissue.

16. The method of claim 15, where the identifying tissue comprises determining if the identified tissue matches a tissue of interest.

19. A method of performing a biopsy of tissue, comprising:

identifying tissue according to the method of claim 13;

and

biopsying at least a portion of the tissue.

17-18. -18. (canceled)

20-22. -22. (canceled)

23. A probe for insertion into tissue, comprising:

a housing;

a radiation source; and

a refractive index measurement assembly.

33. A device for analyzing tissue, comprising:

a low-coherence interferometer; and

the probe of claim 23, optically coupled to the interferometer.

24-32. -32. (canceled)

34-35. -35. (canceled)

36. A computer readable medium, comprising:

a computer program product having computer readable program code for determining a refractive index of tissue from a sample signal of radiation that has impinged upon the tissue,

where the determining the refractive index comprises

reading axial scan data from the sample signal,

truncating the data to a range resulting from known tissue refractive index values,

locating a maximum response intensity,

calculating the refractive index using the maximum response intensity location, and

outputting the resulting refractive index.

37-41. -41. (canceled)