Spectrophotometer for in vivo examination of biological tissue

• US 20040054290A1
• Filed: 02/24/2003
• Published: 03/18/2004
• Est. Priority Date: 01/03/1995
• Status: Abandoned Application

• Current Assignee: Britton Chance
• Original Assignee: Britton Chance
• Inventors: Chance, Britton
• Application Number:
  US10/373,665
• Publication Number:
  US 20040054290A1
• Time in Patent Office: Days
• US Class Current: 600/473
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 2562/146 for optical coupling
• CPC Class Codes: A61B 5/0035 adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
• CPC Class Codes: A61B 5/0042 for the brain
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/0091 for mammography
• 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 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/4312 Breast evaluation or disorder diagnosis A61B5/0091 takes precedence
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6853 with a balloon

Abstract

A spectrophotometric system for examination of biological tissue of interest includes a light source, a light coupling system, a light detector, and a processor. The light source is constructed and arranged to emit a light beam of visible or infra-red radiation. The light coupling sytem includes at least one mirror and is constructed and arranged to receive the emitted light beam and scan the light beam for introduction into the biological tissue of interest. The light detector is optically coupled to detect photons of radiation that have migrated over optical paths in the biological tissue of interest. The processor is operatively coupled to the light source and detector and is adapted to determine an optical property of the biological tissue of interest based on the changes between the introduced and detected radiation.

Claims

1. An optical coupling system for non-invasively monitoring a region of living tissue, comprising:

an excitation port positionable at the tissue and adapted to introduce optical radiation into the monitored tissue;

a first light guide defining an excitation channel for conveying said radiation from a source to said excitation port;

a detection port, positionable at the tissue, adapted to receive radiation that has migrated in the monitored tissue from said excitation port to said detection port, said detection port having a detection area larger than an input area of said excitation port;

a detecting light guide, connected to said detection port, for conveying said radiation from said detection port to an optical detector; and

optical matching fluid, contained within a flexible optically transparent bag, disposed partially around the monitored tissue and said excitation and detection ports.

2. The optical coupling system of claim 1 which includes multiple excitation ports positionable at the tissue and adapted to introduce radiation of said source into the monitored tissue, and multiple light guides each defining an excitation channel for conveying said radiation from said source to the corresponding excitation port.

3. The optical coupling system of claim 1 which includes multiple detection ports positionable at the tissue and adapted to receive radiation that has migrated in the monitored tissue, and multiple detecting light guides each connected to the corresponding detection port for conveying said radiation from the detection port to at least one optical detector.

4. The optical coupling system of claim 1, 2 or 3 wherein said optical matching fluid is positioned partially between said ports and the monitored tissue.

5. The optical coupling system of claim 1, 2 or 3 wherein said optical matching fluid has known scattering or absorptive properties.

6. The optical coupling system of claim 1, 2 or 3 further including means for changing scattering or absorptive properties of said optical matching fluid.

7. The optical coupling system of claim 6 further including means for calibrating said coupling system by controllably changing scattering or absorptive properties of said optical matching fluid.

8. An optical coupler for in vivo examination of biological tissue, comprising:

an optical input port of a selected input area positionable on or near the examined tissue;

a first light guide optically coupled to said optical input port and constructed to transmit optical radiation of a visible or infra-red wavelength from a source to said optical input port;

said optical input port being constructed and arranged to introduce said optical radiation to the examined tissue;

an optical detection port of a selected detection area positionable on or near the examined tissue, said detection port constructed and arranged to receive radiation that has migrated in the examined tissue from said input port to said detection port;

a detector light guide, optically connected to said detection port, constructed to transmit said radiation from said detection port to an optical detector; and

optical medium, disposed at least partially around the examined tissue and said input and detection ports, arranged to limit escape of, or account for photons escaped from the examined tissue.

10. The optical coupler of claim 8 wherein said optical fibers include at said input port or said detection port optical matching medium arranged to achieve a desired coupling of said radiation.

9. An optical coupling system for non-invasively monitoring a region of biological tissue, comprising:

a source probe including at least two optical fibers having distal ends positionable directly at the tissue, each said distal end forming an input port constructed to introduce optical radiation into the examined tissue, said fibers having proximal ends constructed and arranged to form at least one coupling port for receiving said radiation from a source; and

a detection probe including at least one optical fiber having a distal end positionable directly at the tissue, said distal end forming a detection port constructed to receive radiation that has migrated in the examined tissue, said fiber having a proximal end constructed and arranged to form at least one coupling port for conveying said detected radiation to an optical detector.

11. An optical coupler for in vivo examination of biological tissue, comprising:

an optical input port of a selected input area directed toward the examined tissue;

an optical detection port of a selected detection area directed toward the examined tissue;

optical medium disposed at least partially around the examined tissue and said input and detection ports, said optical medium being also placed between the tissue and said input area of said input port and between the tissue and said detection area of said detection port, said optical medium exhibiting known scattering or absorptive properties;

a first light guide optically coupled to said optical input port and constructed to transmit optical radiation of a visible or infra-red wavelength from a source to said optical input port;

said optical input port being constructed and arranged to introduce said radiation to the optical medium;

said optical detection port constructed and arranged to receive radiation that has migrated in the examined tissue and the optical medium from said input port to said detection port; and

a detector light guide, optically coupled to said detection port, constructed to transmit said radiation from said detection port to an optical detector.

12. The optical coupler of claim 8, 9 or 11 wherein said optical medium has absorptive or scattering properties substantially matched to the absorptive or scattering properties of the examined tissue.

13. The optical coupler of claim 8, 9 or 11 further comprising an optical system constructed and arranged to alter controllably absorptive or scattering properties of said optical medium.

14. The optical coupler of claim 13 wherein said system is adapted to substantially match the absorptive or scattering properties of said optical medium to the absorptive or scattering properties of the examined tissue.

15. The optical coupler of claim 8, 9 or 11 further including a second input port of a selected input area, and a light guide optically coupled to said second input port, said detection port placed symmetrically relative to said first input port and said second input port.

16. The optical coupler of claim 15 wherein said input ports and said detection port are arranged in a transmission geometry.

17. The optical coupler of claim 15 wherein said input ports and said detection port are arranged in a backscattering geometry.

18. The optical coupler of claim 8, 9 or 11 wherein said optical ports are movable to another location relative to the examined tissue.

19. The optical coupler of claim 8, 9 or 11 further including multiple input ports, and multiple light guides each optically coupled to the corresponding input port.

20. The optical coupler of claim 19 wherein said multiple input ports are arranged to introduce simultaneously radiation of known time varying pattern to form resulting introduced radiation possessing a substantial gradient of photon density in at least one direction.

21. The optical coupler of claim 20 wherein said optical detection port is movable to another location relative to the examined tissue.

22. The optical coupler of claim 20 wherein said multiple input ports form a one dimensional or two dimensional array.

23. The optical coupler of claim 8, 9 or 11 which includes multiple detection ports, and multiple detector light guides each optically coupled to the corresponding detection port.

24. The optical coupler of claim 8, 9 or 11 wherein said optical medium includes a solid, liquid or gaseous medium.

25. The optical coupler of claim 8, 9 or 11 wherein said optical medium comprises a liquid of selectable scattering or absorptive properties.

26. The optical coupler of claim 8, 9 or 11 wherein said optical medium comprises a pliable solid of selectable scattering or absorptive properties.

27. The optical coupler of claim 8, 9 or 11 wherein said detection area of said optical detection port is larger than said input area of said optical input port.

28. The optical coupler of claim 8, 9 or 11 further including a port for needle localization procedure.

29. The optical coupler of claim 8, 9 or 11 further arranged for ultrasound examination of the tissue performed simultaneously with or subsequently to the optical examination of the tissue.

30. The optical coupler of claim 8, 9 or 11 further including a set of MRI coils arranged to perform an MRI examination of the tissue.

31. An optical coupler for in vivo examination of biological tissue, comprising:

an optical input port of a first selected area directed toward the examined tissue and a second selected area oppositely oriented to said first area;

said input port constructed to accept a light beam scanned over said second area and introduce said beam to the tissue at said first area;

an optical detection port of a selected detection area directed toward the examined tissue;

optical medium disposed at least partially around the examined tissue and said input and detection ports, said optical medium being also placed between the tissue and said input area of said input port and between the tissue and said detection area of said detection port, said optical medium exhibiting known scattering or absorptive properties;

said optical detection port constructed and arranged to receive radiation that has migrated in the examined tissue and the optical medium from said input port to said detection port; and

a detector light guide, optically coupled to said detection port, constructed to transmit said radiation from said detection port to an optical detector.

32. The optical coupling system of claim 31 wherein said detection area of said optical detection port comprises a multiplicity of detection subareas located at a known position of said detection area, each said detection subarea constructed and arranged to receive radiation that has migrated in the examined tissue and convey said received radiation to a detector.

33. The optical coupling system of claim 32 wherein said optical detector includes an array of semiconducting detectors each receiving light from a corresponding detection subarea via said detector light guide.

34. The optical coupling system of claim 31 wherein said light beam is scanned over said input port using a selected pattern relative to a detection sequence accumulated over said detection subareas.