METHOD AND APPARATUS FOR IMAGING TISSUES

• US 20070276256A1
• Filed: 08/13/2007
• Published: 11/29/2007
• Est. Priority Date: 02/17/2005
• Status: Active Grant

• Current Assignee: Microsoft International Holdings BV (Microsoft Corporation)
• Original Assignee: 3DV Systems Ltd. (Microsoft Corporation)
• Inventors: Iddan, Gavriel
• Granted Patent: US 7,684,601 B2
• Time in Patent Office: Days
• US Class Current: 600/473
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/0091 for mammography
• CPC Class Codes: A61B 5/4312 Breast evaluation or disorder diagnosis A61B5/0091 takes precedence
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: Y10S 128/922 including image analysis

Abstract

Method and apparatus for imaging tissue by upstream illumination and downstream dual filtering of the exiting light for separation of ballistic photons rays from stray rays. Dual filtering includes spatial filtering via a pinhole and spatial filtering operated by a fast gate. A processor synchronizes flashes of illumination with the fast gate to command opening for passage of the ballistic photons rays and closure to exclude the stray rays. An image detector downstream of the fast gate collects the ballistic photons rays for processing by the processor and display on a monitor as a shadowgram. Illumination flashes have one or more wavelengths and the image detector is adapted to match the selected wavelengths of the illuminating flashes.

Claims

1. A method for imaging tissue under examination, comprising:

a source of illumination disposed upstream and emitting light directed onto the tissue for passage therethrough and for exit therefrom as downstream exiting light,

an image detector disposed downstream of the tissue for receiving light, and for emitting signals derived from the received light,

a processing unit coupled to the image detector for receiving emitted signals, for processing received signals, and for delivering processed data, the method being comprising the steps of;

coupling the processing unit to and in command of the illumination source for triggering emission of at least one pulse of light lasting for a predetermined duration of time,

operating a fast gate coupled to and under command of the processing unit and disposed upstream of the image detector, to open into a first open state and to close into a second closed state in predetermined synchronization with the at least one pulse of light for selectively permitting passage to the image detector of only ballistic photon rays pertaining to the exiting light, and

operating the processing unit to derive an image from the signals received by the image detector.

2. the method according to claim 1, wherein:

the derived image is displayed on a monitor appropriately coupled to the processing unit.

3. The method according to claim 1, wherein:

the source of illumination is configured to emit light selected alone and in combination from the group consisting of invisible light, visible light, coherent light, white light, and infrared light.

4. The method according to claim 1, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths of light, and

a discrete wavelength out of the plurality of different discrete wavelengths, is controllably selected,

whereby the source of illumination is triggered to emit at least one pulse of light in at least one selected wavelength.

5. The method according to claim 1, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths of light, and

a discrete wavelength out of the plurality of different discrete wavelengths is controllably selected,

whereby the source of illumination is triggered to emit a sequence of pulses of light including at least two different wavelengths.

6. The method according to claim 1, wherein:

the duration of the at least one pulse of light is selected to last for at least one nanosecond.

7. The method according to claim 1, wherein:

the duration of the at least one pulse of light is selected to last for less than one nanosecond.

8. The method according to claim 1, wherein:

the fast gate is operated to open from the closed state into the open state within less than one nanosecond.

9. The method according to claim 1, wherein:

the fast gate is operated to open from the closed state into the open state within less than 100 picoseconds.

10. The method according to claim 1, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths,

a discrete wavelength out of the plurality of different discrete wavelengths is controllably selected, and the source of illumination is triggered to emit a sequence of pulses of light including at least two different wavelengths, and

a monitor is coupled to the processing unit for displaying an image of superimposed wavelengths derived from the tissue under examination.

11. The method according to claim 1, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths,

the gate is selected to match the wavelength(s) of the emitted light.

12. The method according to claim 1, wherein:

a time-interval separating two successive at least one pulse of light is appropriately controlled by the processing unit to ensure opening of the gate to the open state to allow passage of only ballistic photons.

13. The method according to claim 1, wherein:

exiting light is directed to pass through a pinhole of small dimension having a first side and a second side, and

the gate is supported on either one of both the first side and the second side of the pinhole and is configured to match the small dimension of the pinhole,

whereby a gate of small dimension is operable for tissue imaging.

14. The method according to claim 1, wherein:

the imaging detector provides enhanced images by incorporating an image amplifier elected from the group consisting of an electron multiplying CCD (Charged Coupled Device), and a CMOS (Complementary Metal-Oxyde Semiconductor) imager with an APD (Avalanche Photodiode Device).

15. The method according to claim 1, wherein:

tissue is imaged by upstream illumination and downstream dual filtering of the exiting light for separation of ballistic photons rays from stray rays

16. The method according to claim 1, wherein:

the illumination source illuminates the tissue in either one of both single wavelength illumination and multiple wavelength illumination.

17. An apparatus for imaging tissue under examination, comprising:

a source of illumination disposed upstream and emitting light directed onto the tissue for passage therethrough and for exit therefrom as downstream exiting light,

an image detector disposed downstream of the tissue for receiving light, and for emitting signals derived from the received light,

a processing unit coupled to the image detector for receiving emitted signals, for processing received signals, and for delivering processed data, the apparatus comprising

the processing unit being coupled to and in command of the illumination source for triggering emission of at least one pulse of light lasting for a predetermined duration of time,

a fast gate coupled to and under command of the processing unit and disposed upstream of the image detector, to open into a first open state and to close into a second closed state in predetermined synchronization with the at least one pulse of light, for selectively permitting passage to the image detector of only ballistic photon rays pertaining to the exiting light, and

the processing unit being operated to derive an image from the signals received by the image detector.

18. The apparatus according to claim 17, wherein:

the derived image is displayed on a monitor appropriately coupled to the processing unit.

19. The apparatus according to claim 17, wherein:

the source of illumination is configured to emit light selected alone and in combination from the group consisting of invisible light, visible light, coherent light, white light, and infrared light.

20. The apparatus according to claim 17, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths of light, and

a discrete wavelength out of the plurality of different discrete wavelengths, is controllably selected,

whereby the source of illumination is triggered to emit at least one pulse of light in at least one selected wavelength.

21. The apparatus according to claim 17, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths of light, and

a discrete wavelength out of the plurality of different discrete wavelengths is controllably selected,

whereby the source of illumination is triggered to emit a sequence of pulses of light including at least two different wavelengths.

22. The apparatus according to claim 17, wherein:

the duration of the at least one pulse of light is selected to last for at least one nanosecond.

23. The apparatus according to claim 17, wherein:

the duration of the at least one pulse of light is selected to last for at least one nanosecond.

24. The apparatus according to claim 17, wherein:

the duration of the at least one pulse of light is selected to last for less than one nanosecond.

25. The apparatus according to claim 17, wherein:

the fast gate is operated to open from the closed state into the open state within less than 100 picoseconds.

26. The apparatus according to claim 17, wherein:

the source of illumination is configured to emit light) in a plurality of different discrete wavelengths,

a discrete wavelength out of the plurality of different discrete wavelengths is controllably selected, and the source of illumination is triggered to emit a sequence of pulses of light including at least two different wavelengths, and

a monitor is coupled to the processing unit for displaying an image of superimposed wavelengths derived from the tissue under examination.

27. The apparatus according to claim 17, wherein:

the source of illumination is configured to emit light in a plurality of different discrete wavelengths,

the gate is selected to match the wavelength(s) of the emitted light.

28. The apparatus according to claim 17, wherein:

a time-interval separating two successive at least one pulse of light is appropriately controlled by the processing unit to ensure opening of the gate to the open state to allow passage of only ballistic photons

29. The apparatus according to claim 17, wherein:

exiting light is directed to pass through a pinhole of small dimension having a first side and a second side, and

the gate is supported on either one of both the first side and the second side of the pinhole, and is configured to match the small dimension of the pinhole,

whereby a gate of small dimension is operable for tissue imaging.

30. The apparatus according to claim 17, wherein:

the imaging detector provides enhanced images by incorporating an image amplifier selected from the group consisting of an electron multiplying CCD (Charged Coupled Device), and a CMOS (Complementary Metal-Oxyde Semiconductor) imager with an APD (Avalanche Photodiode Device).

31. The apparatus according to claim 17, wherein:

tissue is imaged by upstream illumination and downstream dual filtering of the exiting light for separation of ballistic photons rays from stray rays.

32. The method according to claim 17, wherein:

the illumination source illuminates the tissue in either one of both single wavelength illumination and multiple wavelength illumination.