System for Detecting Fluorescence and Projecting a Representative Image

• US 20140187931A1
• Filed: 12/05/2013
• Published: 07/03/2014
• Est. Priority Date: 12/05/2012
• Status: Active Grant

• Current Assignee: AccuVein LLC
• Original Assignee: AccuVein LLC
• Inventors: Wood, Fred, Yavid, Dmitry, Goldman, Ron, Zott, Joe
• Granted Patent: US 10,517,483 B2
• Time in Patent Office: Days
• US Class Current: 600/431
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

A fluorescence imaging device detects fluorescence in parts of the visible and invisible spectrum, and projects the fluorescence image directly on the human body, as well as on a monitor, with improved sensitivity, video frame rate and depth of focus, and enhanced capabilities of detecting distribution and properties of multiple fluorophores. Direct projection of three-dimensional visible representations of florescence on three-dimensional body areas advantageously permits view of it during surgical procedures, including during cancer removal, reconstructive surgery and wound care, etc. A NIR laser and a human visible laser (HVL) are aligned coaxially and scanned over the operating field of view. When the NIR laser passes over the area where the florescent dye is present, it energizes the dye which emits at a shifted NIR frequency detected by a photo diode. The HVL is turned on when emission is detected, providing visual indication of those positions.

Claims

1. A fluorescence imaging device for detecting fluorescence in biologic tissues and projecting a representative image onto said tissues, comprising:

(a) means of generating and delivering excitation light to biologic tissues containing fluorescent substances;

(b) means of collecting light emitted by said fluorescent substances;

(c) means of analyzing said emitted light and establishing the spatial distribution of its intensity in the biological tissue;

(d) means of generating an image representative of said distribution; and

(e) means of projecting said image onto said biologic tissues in human-visible colors.

2. The fluorescence imaging device of claim 1 which also includes a source of ablation light controllably delivered to select areas of high concentration of detected fluorophore.

3. The fluorescence imaging device of claim 1 where the source of excitation light comprises one or more lasers scanned in a raster pattern along the outer surface of biological tissue.

4. The fluorescence imaging device of claim 3 where the emitted light is collected by a non-imaging optical system.

5. The fluorescence imaging device of claim 3 where the emitted light is analyzed in time domain.

6. The fluorescence imaging device of claim 3 where the emitted light is detected by one of the following time-domain detectors:

(a) photo-diode (PD);

(b) avalanche photo-diode (APD);

(c) photo-multiplier tube (PMT);

(d) hybrid photo-multiplier (HPM); and

(e) silicon photo-multiplier (SiPM).

7. The fluorescence imaging device of claim 3 where the emitted light is detected by multiple detectors at the same wavelength, each having a separate optical collection system.

8. The fluorescence imaging device of claim 3 where the emitted light is detected by multiple detectors at multiple wavelengths simultaneously.

9. The fluorescence imaging device of claim 3 where the excitation light is delivered at multiple wavelength and excites multiple fluorescent substances.

10. The fluorescence imaging device of claim 3 where the excitation light is delivered at wavelength not matching the maximum absorption of the fluorescent substances present in biological tissue.

11. The fluorescence imaging device of claim 3 where the emitted light is non-human visible.

12. The fluorescence imaging device of claim 3 where one or both the excitation and emission light is NIR light with the wavelength between 700 and 1000 nm.

13. The fluorescence imaging device of claim 3 where the image representing the fluorescence is projected by means of one or more visible laser beams delivered through the same raster scanner as the excitation laser beam.

14. The fluorescence imaging device of claim 3 which includes means for capturing image in human-visible spectrum of substantially the same area as covered by laser scanner.

15. The fluorescence imaging device of claim 14, where said means of capturing image in human-visible spectrum comprise a pixelated 2D imaging detector, such as a CCD or CMOS camera.

16. The fluorescence imaging device of claim 15, where the fields of view (FOY) of said camera and laser scanner are coaxially aligned by optical means.

17. The fluorescence imaging device of claim 16, where said coaxial alignment is achieved by means of dichroic mirrors.

18. The fluorescence imaging device of claim 16, where said coaxial alignment is achieved by means of polarizing mirrors.

19. The fluorescence imaging device of claim 16, where said coaxial alignment is achieved by means of semi-transparent mirrors.

20. The fluorescence imaging device of claim 15, where the fields of view (FOY) of said pixelated 2D imaging detector and laser scanner are partially aligned by optical means.

21. The fluorescence imaging device of claim 20, where said partial alignment is achieved by means of a bounce mirror for the scanner just outside of the camera FOV.

22. The fluorescence imaging device of claim 20, where said partial alignment is achieved by means of a bounce mirror for the camera just outside of the scanner FOV.

23. The fluorescence imaging device of claim 15, where the frame rates of scanner and camera are synchronized.

24. The fluorescence imaging device of claim 23, where the camera captures images while the projection lasers are turned off.

25. The fluorescence imaging device of claim 23, where the camera captures the images into two separate video streams:

the first stream contains the images captured while the projection lasers are turned off and the second stream contains the images captured while the projection lasers are turned on.

26. The fluorescence imaging device of claim 25, where the image processor compares both video streams and extract alignment information between scanner and camera.

27. The fluorescence imaging device of claim 3 where the emitted light is delivered in pulses shorter than the duration of light collection for a single acquired pixel.

28. The fluorescence imaging device of claim 27 where the temporal distribution of fluorescent light in response to said short pulses is analyzed.

29. The fluorescence imaging device of claim 28 where the emitted light is detected by a single photon counter.

30. The fluorescence imaging device of claim 27 where the excitation light from different lasers is delivered in a sequence of short pulses counter.

31. The fluorescence imaging device of claim 27 where the information about the depth of fluorescent substance in the biological tissue is extracted from time delay between the emission of an excitation pulse and arrival of the emission pulse.

32. The fluorescence imaging device of claim 27, where the excitation laser is on for the first part of each pixel and is off for the second part of each pixel, and where the intensity of collected light during the second part is subtracted from the intensity of collected light during the first part in order to cancel out signals from non-fluorescent ambient light.

33. The fluorescence imaging device of claim 1 where the means of projecting the image is a 2D pixelated projector, such as a DLP or LCoS projector.

34. The fluorescence imaging device of claim 1 where the image representing the fluorescence is enhanced by time variations of the brightness of various areas of the image.

35. The fluorescence imaging device of claim 1 where the image representing the fluorescence is enhanced by indication of temporal changes in detected fluorescent light.

36. The fluorescence imaging device of claim 1 where the bit resolution of the image, representing the fluorescence is automatically adjusted to optimize the contrast and reduce visible noise.

37. The fluorescence imaging device of claim 1 where the dynamic range image representing the fluorescence is automatically adjusted to be always above the noise floor.

38. The fluorescence imaging device of claim 1 where multiple fluorescent images are averaged out to form the projected image with lower level of noise.

39. The fluorescence imaging device of claim 1 where the bandwidth of acquired fluorescent image is automatically adjusted to reduce the level of noise.

40. The fluorescence imaging device of claim 1 where multiple fluorescent images are averaged out to form the projected image with lower level of noise.

41. The fluorescence imaging device of claim 1 where polarized light is used to project the fluorescence-representative image onto biologic tissues in human-visible colors.

42. The fluorescence imaging device of claim 1 where the light source used to project fluorescence-representative image is also used for general illumination of the surgical area.

43. The fluorescence imaging device of claim 1 where the acquisition of fluorescent image and projection of fluorescence-representative image are separated in time.

44. The fluorescence imaging device of claim 1 configured to acquire the fluorescent image from 3D biological bodies and organs and to project fluorescence-representative image on curved surfaces of same biological bodies and organs.

45. The fluorescence imaging device of claim 1 configured to acquire the fluorescent image from 3D biological bodies and organs, to project fluorescence-representative image on curved surfaces of same biological bodies and organs, to acquire the visible image of the same area, including at least part of projected fluorescence-representative image, to co-analyze the acquired fluorescent image and the acquired visible projected image and to apply adjustments to projected image in order to insure the accurate positional match of fluorescent and projected images on curved surfaces of 3D biological bodies and organs.

46. The fluorescence imaging device of claim 1 where the intensity of excitation light spatially varies depending on the content of acquired fluorescent image.

47. A fluorescence imaging device for detecting fluorescence in biologic tissues comprising:

(a) one or more lasers emitting excitation light, scanned in a raster pattern along the outer surface of biological tissues containing fluorescent substances;

(b) means of collecting light emitted by said fluorescent substances;

(c) means of analyzing said emitted light in time domain and establishing the spatial distribution of its intensity in the biological tissue;

(d) means of generating an image representative of said distribution; and

(e) means of displaying said image on a monitor for human vision.

48. The fluorescence imaging device of claim 47 where the emitted light is collected by a non-imaging optical system.

49. The fluorescence imaging device of claim 47 where the emitted light is detected by one of the following time-domain detectors:

(a) photo-diode (PD);

(b) avalanche photo-diode (APD);

(c) photo-multiplier tube (PMT);

(d) hybrid photo-multiplier (HPM); and

(e) silicon photo-multiplier (SiPM).

50. The fluorescence imaging device of claim 47 where the emitted light is detected by multiple detectors at the same wavelength, each having a separate optical collection system.

51. The fluorescence imaging device of claim 47 where the emitted light is detected by multiple detectors at multiple wavelengths simultaneously.

52. The fluorescence imaging device of claim 47 where the excitation light is delivered at multiple wavelength and excites multiple fluorescent substances.

53. The fluorescence imaging device of claim 47 where the excitation light is delivered at wavelength not matching the maximum absorption of the fluorescent substances present in biological tissue.

54. The fluorescence imaging device of claim 47 where the emitted light is non-human visible.

55. The fluorescence imaging device of claim 47 where one or both the excitation and emission light is NIR light with the wavelength between 700 and 1000 nm.

56. The fluorescence imaging device of claim 47 where the excitation light is delivered to internal organs and structures inside a biological body through an endoscope.

57. The fluorescence imaging device of claim 56 where the fluorescent light is collected by one or more detectors outside of the boundaries of biological body.

58. The fluorescence imaging device of claim 47 where the emitted light is delivered in pulses shorter than the duration of light collection for a single acquired pixel.

59. The fluorescence imaging device of claim 58 where the temporal distribution of fluorescent light in response to said short pulses is analyzed.

60. The fluorescence imaging device of claim 59 where the emitted light is detected by a single photon counter.

61. The fluorescence imaging device of claim 58 where the excitation light from different lasers is delivered in a sequence of short pulses counter.

62. The fluorescence imaging device of claim 58 where the information about the depth of fluorescent substance in the biological tissue is extracted from time delay between the emission of an excitation pulse and arrival of the emission pulse.

63. The fluorescence imaging device of claim 58, where the excitation laser is on for the first part of each pixel and is off for the second part of each pixel, and where the intensity of collected light during the second part is subtracted from the intensity of collected light during the first part in order to cancel out signals from non-fluorescent ambient light.

64. The fluorescence imaging device of claim 47 where the intensity of excitation light spatially varies depending on the content of acquired fluorescent image.

65. The fluorescence imaging device of claim 47 which also includes an ablation laser scanned in a raster pattern together with lasers emitting excitation light, and controlled to deliver ablation light to select areas of high concentration of detected fluorophore.