Spectroscopy illuminator with improved delivery efficiency for high optical density and reduced thermal load

• US 20030191379A1
• Filed: 04/09/2002
• Published: 10/09/2003
• Est. Priority Date: 04/09/2002
• Status: Active Grant

• Current Assignee: JB IP Acquisitions LLC
• Original Assignee: Spectros Corporation (AliphCom Corp.)
• Inventors: Benaron, David A., Parachikov, Ilian H.
• Granted Patent: US 6,711,426 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/14558 by polarisation
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/42 Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems A61B1/00, A61B5/4857, A61B5/486, A61B5/4866, A61B5/4869 take precedence
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01N 2201/062 LED's

Abstract

An improved illuminator for generating broadband light, and for delivering the light to a sample with an improved delivery efficiency, for higher optical density and/or reduced thermal transfer, than achieved with conventional halogen bulb sources. The illuminator enables spectroscopic analysis in thermally-sensitive or spatially-constrained environments. A phosphor-coated broadband white LED and integrated collimating optics produces a continuous, collimated broadband light beam from 400 nm to 700 nm, which is then transmitted through space to a sample region, such as a living tissue in vivo. This results in a high net efficient delivery of light to the tissue sample. An efficient conversion of power to light, and the high delivery efficiency, keeps both the illuminator and sample cool during operation, allowing the illuminator to be integrated into the tip of a medical probe or into monitoring systems.

Claims

1. An improved broadband spectroscopy illuminator comprising:

a broadband light source and an optical coupling means for coupling the light source to a target region, said source and optical coupling means configured and arranged to achieve an improved efficiency of delivery to said region with a high optical density of at least 1 mW/cm² and a low transferable thermal load of no more than 100 mW heat per mW usable optical power delivered.

2. The illuminator of claim 1, wherein said light source is a high conversion efficiency light source selected to operate with a typical conversion efficiency of at least 15%, said improved efficiency of delivery resulting at least in part from said high conversion efficiency.

3. The illuminator of claim 1 or 2, wherein said light source comprises a broadband LED.

4. The illuminator of claim 3, wherein said light source comprises a white LED.

5. The illuminator of claim 1 or 2, wherein said light source comprises a blue LED optically coupled to a Lumigen™

reservoir.

6. The illuminator of claim 1, wherein said coupling means includes transfer optics selected and arranged so as to achieve an improvement in transfer efficiency of at least 2-fold, as compared to a transfer efficiency of said illuminator in the absence of said transfer optics, said improved efficiency of delivery at least in part a result of said improved transfer efficiency.

7. The illuminator of claim 6, wherein said transfer optics includes at least one collimation lens.

8. The illuminator of claim 7, wherein said at least one collimation lens is integral to the bulb of a lamp, said collimation lens arranged to have its proximal surface located no more than 10 mm from the source of said light within said lamp.

9. The illuminator of claim 6, wherein said transfer optics includes at least one refocusing lens.

10. The illuminator of claim 9, wherein said coupling means includes an optical fiber, and said refocusing lens is focused on the illumination end of said optical fiber.

11. The illuminator of claim 6, wherein said broadband light source is fiber-coupled to said target region, said coupling means includes at least one thermally-insulating optical fiber, said fiber is proximally optically coupled to said source and distally optically coupled to said target region.

12. The illuminator of claim 11, wherein said source comprises a halogen recycle filament bulb lamp, said coupling means comprises a collimating lens optically coupled to the filament and a reverse beam expander optically coupled to the collimating lens, said collimating lens integral to the bulb of said lamp and arranged to have its proximal surface located no more than 10 mm from the filament of said lamp, and said reverse expander further optically coupled to said optical fiber.

13. The illuminator of claim 1, wherein said illuminator is further arranged so as to be removably optically coupled to a medical probe.

14. The illuminator of claim 1, wherein said illuminator is further incorporated into the body of a medical probe.

15. The illuminator of claim 1, wherein said illuminator is further incorporated into the patient end of a medical probe.

16. The illuminator of claim 13, 14, or 15 wherein said medical probe is selected from the list of medical probes consisting of catheters, sheaths, guidewires, needles, trocars, surgical instruments, and injection probes.

17. The illuminator of claim 1, wherein said illuminator is further incorporated into a medical system.

30. The illuminator of claim 1, wherein said illuminator further comprises a light collection fiber, said light collection fiber integrated into said illuminator and optically coupled to said target region.

18. A medical illuminator catheter comprising:

(a) a biocompatible catheter sheath, said catheter sheath having a monitor end, a central body, and a patient end;

(b) a mixed optical and electrical connection plug, said plug located at or near the monitor end of said catheter;

(c) an integral broadband light source for illuminating a target region and a collimating transfer lens for optically coupling said source to said region over free space, said source and lens integrated into said body of said catheter, said source and lens further selected and arranged so as to deliver to said region an optical density of at least 1 mW/cm² over said target region with a transferable thermal load of no more than 100 mW heat per mW usable optical power delivered;

(d) an optical collection fiber for collecting light scattered from said target region and for transmitting said collected light from said patient end of the catheter, along a length of said catheter, to a said connection plug at or near said monitor end of the catheter, and,

(e) power supply wires for transmitting electrical power to said light source, said wires traversing a length of said catheter and electrically connected to both said light source and said connection plug.

19. The illuminator catheter of claim 18, further including a battery, said battery integrated into the body of said catheter.

20. The illuminator catheter of claim 19, further including a power switch for switching said illuminator off and on.

21. The illuminator catheter of claim 18, further including an information storage device, for storing information related to the catheter function, serial number, and use history.

23. The illuminator of claim 18 or 22, wherein said broadband light source is a broadband LED.

22. An illuminator catheter comprising:

(a) a biocompatible catheter sheath, said catheter sheath having a monitor end, a central body, and a patient end;

(b) an optical connection plug, said plug located at or near the monitor end of said catheter;

(c) an integral broadband LED light source for illuminating a target region and a collimating transfer lens for optically coupling said source to said region over free space, said source and lens integrated into said body of said catheter

(d) a power source, integrated into said body of said catheter, said source switchably connected to said light source via an electrical switch;

(e) an optical collection fiber for collecting light scattered from said target region and for transmitting said collected light from said patient end of the catheter, along a length of said catheter, to a connection plug at or near said monitor end of the catheter, and,

(f) power supply wires for transmitting electrical power to said light source, said wires traversing a length of said catheter from said power source to said light source.

24. A medical illuminator probe, comprising:

(a) a biocompatible probe sheath, said sheath having a monitor end, a central body, and a patient end;

(b) a fiber optic connection plug for reversibly connecting the probe to a medical illuminator, said plug located at or near the monitor end of said catheter;

(c) a thermally-insulating illumination fiber for transmitting illumination from said illuminator, through said plug, along a length of said probe, to a target region,

(d) a collection fiber for collecting said illumination after said illumination has scattered from said region, and for transmitting said collected light to said connection plug.

25. A method of monitoring tissue oxygenation involving:

(a) placing an oximeter probe near a living tissue;

(b) illuminating the tissue with a broadband illumination;

(c) monitoring light returning from the tissue, said light comprising at least one set of visible wavelengths from 400 to 700 nm;

(d) determining a tissue oxygenation index; and

(e) displaying said index.

26. The method of claim 25 wherein said tissue is selected from the list of tissues consisting of oropharynx, nasopharynx, esophagus, stomach, duodenum, ileum, colon, or other gastrointestinal tissues.

27. A medical illuminator probe, comprising:

(a) a biocompatible probe sheath, said sheath having a monitor end, a central body, and a patient end;

(b) a fiber optic connection plug for connecting the probe to a medical illuminator, said plug located at or near the monitor end of said catheter;

(c) a thermally-insulating illumination fiber for transmitting illumination from said illuminator, through said plug, along a length of said probe, to a target region, said illumination provided at a transferable optical density of at least 10 mW/mm² into said fiber with negligible transferable thermal load;

(d) a collection fiber for collecting said illumination after said illumination has scattered from said region, and for transmitting said collected light to said connection plug.

28. A method of monitoring tissue oxygenation involving:

(a) illuminating the tissue with a broadband illumination;

(b) monitoring light returning from the tissue;

(c) determining a tissue oxygenation index; and

(d) displaying said index.

29. The method of claim 28 wherein said broadband illumination comprises a portion of the band from 500 nm to 600 nm.

31. The method of claim 28 wherein said determining involves the determination of oxygenation over time during a medical intervention, wherein said intervention is further modified based upon the result of said determination.