SYSTEM AND METHOD FOR SUB-SURFACE FLUORESCENCE IMAGING

• US 20120326055A1
• Filed: 12/17/2010
• Published: 12/27/2012
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: University Health Network
• Original Assignee: University Health Network
• Inventors: Wilson, Brian Campbell, Kim, Anthony Taywon
• Granted Patent: US 9,134,243 B2
• Time in Patent Office: Days
• US Class Current: 250/459.1
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 5/0042 for the brain
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61B 5/445 Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/4406 Fluorescence spectrometry
• CPC Class Codes: G01N 2021/6419 Excitation at two or more wavelengths
• CPC Class Codes: G01N 21/6458 Fluorescence microscopy fluorescence microscopes per se G02B21/0076 and G02B21/16
• CPC Class Codes: G02B 21/16 adapted for ultraviolet illumination ; Fluorescence microscopes G02B21/0076 takes precedence
• CPC Class Codes: G02B 21/367 providing an output produced by processing a plurality of individual source images, e.g. image tiling, montage, composite images, depth sectioning, image comparison
• CPC Class Codes: G07D 7/1205 Testing spectral properties
• CPC Class Codes: G07D 7/128 Viewing devices

Abstract

A system for sub-surface fluorescence imaging is provided, the system comprising: an excitation source for selectably emitting light at at least one of at least two excitation wavelengths or wavelength ranges at a target surface; and a light detector for detecting fluorescence emission wavelengths or wavelength ranges from the target surface; wherein at least one of the at least two excitation wavelengths or wavelength ranges causes fluorescing of at least one marker at a sub-surface depth, the emitted light at each of the at least two excitation wavelengths or wavelength ranges having different depths of optical penetration and causing fluorescing at respective different depths. A method for sub-surface fluorescence imaging is also provided, in some cases exemplified by a reconstruction of the sub-surface fluorescence topography.

Claims

1. A system for sub-surface fluorescence topographical imaging comprising:

an excitation source for selectably emitting light at at least one of at least two excitation wavelengths or wavelength ranges at a target surface; and

a light detector for detecting fluorescence emission wavelengths or wavelength ranges from the target surface;

wherein at least one of the at least two excitation wavelengths or wavelength ranges causes fluorescing of at least one marker at a sub-surface depth, the emitted light at each of the at least two excitation wavelengths or wavelength ranges having different depths of optical penetration and causing fluorescing at respective different depths.

2. The system of claim 1 wherein the at least one marker corresponds to an object having an object top surface layer at a sub-surface depth that faces towards the target surface, and fluorescing of the at least one marker corresponding to the object top surface layer is detected by the light detector.

3. The system of claim 1 wherein the excitation source comprises a broadband light source and a plurality of excitation filters, each excitation filter being selectably positionable to filter light from the broadband light source in order to produce a respective one of the at least two excitation wavelengths or wavelength ranges.

5. The system of claim 1 wherein the excitation source comprises a plurality of light sources, each of the plurality of light sources being selectable for emitting a respective one of the at least two excitation wavelengths or wavelength ranges.

9. The system of claim 1 wherein the light detector comprises a detection filter positionable to filter emitted light from the target surface in order to restrict emission wavelengths detected by the light detector.

15. The system of claim 1 wherein the excitation source is configured to emit the at least two excitation wavelengths or wavelength ranges concurrently with frequency modulation.

20. The system of claim 1 wherein a turbid light-absorbing medium is below the target surface.

23. The system of claim 1 further comprising a fiberoptic probe housing fiberoptics for emitting the excitation wavelengths or wavelength ranges to the target surface and for receiving the fluorescence emission wavelengths or wavelength ranges.

24. The system of claim 1 further comprising a processor configured to execute instructions for:

determining a fluorescence measurement for each of the at least two excitation wavelengths or wavelength ranges using the detected fluorescence emission wavelengths or wavelength ranges, and associating the fluorescence measurement with the respective depth of each of the at least two excitation wavelengths or wavelength ranges; and

constructing a sub-surface fluorescence topographical image using the determined fluorescence measurements and associated depths.

25. The system of claim 9 wherein the detected fluorescence emission wavelengths or wavelength ranges correspond to a top surface layer of an object at a sub-surface depth, and constructing the sub-surface fluorescence topographical image comprises constructing a fluorescence topographical image of the top surface layer of the object.

27. The system of claim 1 further comprising a measurement probe for measuring at least one optical property of the target surface.

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30. A method for sub-surface fluorescence imaging comprising:

illuminating a target surface with light at at least two excitation wavelengths or wavelength ranges;

wherein at least one of the at least two excitation wavelengths or wavelength ranges causes fluorescing of at least one marker at a sub-surface depth, the light at each of the at least two excitation wavelengths or wavelength ranges having different depths of optical penetration and causing fluorescing at respective different depths;

detecting fluorescence emission wavelengths or wavelength ranges from the target surface;

determining a fluorescence calculation for each of the at least two excitation wavelengths or wavelength ranges using the detected fluorescence emission wavelengths or wavelength ranges; and

constructing a sub-surface fluorescence topographical image using the determined fluorescence calculations.

31. The method of claim 30 wherein the detected fluorescence emission wavelengths or wavelength ranges correspond to a top surface layer of an object at a sub-surface depth, and constructing the sub-surface fluorescence topographical image comprises constructing a fluorescence topographical image of the top surface layer of the object.

33. The method of claim 30 wherein the target surface is successively illuminated with the at least two excitation wavelengths or wavelength ranges.

34. The method of claim 30 wherein the target surface is simultaneously illuminated with the at least two excitation wavelengths or wavelength ranges, the at least two excitation wavelengths or wavelength ranges being frequency modulated.

35. The method of claim 30 further comprising:

illuminating the target surface with light over a major portion of the emission wavelengths or wavelength ranges;

measuring a background reflectance from the target surface;

wherein constructing the sub-surface fluorescence topographical image accounts for the background reflectance.

36. The method of claim 35 wherein the light over the major portion of the emission wavelengths or wavelength ranges is broadband white light.

37. The method of claim 30 wherein the fluorescence calculation is one of:

a ratio of detected fluorescence for each excitation wavelength or wavelength ranges to a reference measured emitted fluorescence for a reference excitation wavelength or wavelength ranges; and

a depth range for each detected fluorescence associated with the respective depth of each excitation wavelength or wavelength range.

38. The method of claim 37 wherein the fluorescence calculation is used in a sub-surface fluorescence model to construct the sub-surface fluorescence topographical image.

39. The method of claim 30 further comprising:

detecting at least one optical property of the target surface relevant to the sub-surface fluorescence model.

40. The method of claim 30 further comprising:

providing a fluorescence marker to target the at least one marker.

53. The method of claim 30 wherein a turbid light-absorbing medium is below the target surface.

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