Phase Contrast Microscopy With Oblique Back-Illumination

Patent metadata

Field	Value
Publication number	US-2015087902-A1
Application number	US-201314388847-A
Country	US
Kind code	A1
Filing date	Mar 15, 2013
Priority date	Mar 30, 2012
Publication date	Mar 26, 2015
Grant date	—

Abstract

A method of creating a phase contrast image is provided. In some embodiments the method comprises illuminating the target region of a sample with a first light source to provide a first oblique back illumination of the target region of the sample, and detecting a first phase contrast image from light originating from the first light source and back illuminating the target region of the sample. In some embodiments the method further comprises illuminating the sample with a second light source to provide a second oblique back illumination of the target region of the sample, and detecting a second phase contrast image from light originating from the second light source and back illuminating the target region of the sample. In some embodiments a difference image of the target region of the sample is created by subtracting the second phase contrast image of the target region of the sample from the first phase contrast image of the target region of the sample. Apparatus for carrying out the methods are also provided. The methods and apparatus find use, for example, in endoscopy.

First claim

1 . A method of creating a phase contrast image, comprising:
illuminating the target region of a sample with a first light source to provide a first oblique back illumination of the target region of the sample, and detecting a first phase contrast image from light originating from the first light source and back illuminating the target region of the sample.

2 . The method of claim 1 , wherein light from the first light source is the only light illuminating the sample when the first phase contrast image is detected from light originating from the first light source and back illuminating the target region of the sample.

3 . The method of claim 2 , further comprising illuminating the sample with a second light source to provide a second oblique back illumination of the target region of the sample, and
detecting a second phase contrast image from light originating from the second light source and back illuminating the target region of the sample.

4 . The method of claim 3 , further comprising creating a difference image of the target region of the sample by subtracting the second phase contrast image of the target region of the sample from the first phase contrast image of the target region of the sample.

5 . The method of claim 3 or claim 4 , further comprising creating an absorption contrast image of the target region of the sample by adding the first phase contrast image of the target region of the sample to the second phase contrast image of the target region of the sample.

6 . The method of any one of claims 1 - 5 , wherein the axis of illumination of the sample with the first light source and the axis of detection of light originating from the first light source and back illuminating the target region are different.

7 . The method of any one of claims 1 and 3 - 6 , wherein the axis of illumination of the sample with the second light source and the axis of detection of light originating from the second light source and back illuminating the target region are different.

8 . The method of any one of claims 3 - 7 , wherein the axis of detection of light originating from the first light source and back illuminating the target region and the axis of detection of light originating from the second light source and back illuminating the target region are different.

9 . The method of any one of claims 3 - 7 , wherein the axis of detection of light originating from the first light source and back illuminating the target region and the axis of detection of light originating from the second light source and back illuminating the target region are the same.

10 . The method of any one of claims 3 - 9 , wherein the wavelength of the light from the first light source and the wavelength of light from the second light source are different.

11 . The method of any one of claims 1 - 10 , wherein the wavelength of the light from the first and second light sources is from 0.2 to 300 μm.

12 . The method of any one of claims 1 - 11 , wherein the light source(s) is selected from a light-emitting diode (LED), a laser, a supercontinuum light source, or a superluminescent diode (SLED).

13 . The method of any one of claims 1 - 12 , wherein the detecting is by a photo detector array.

14 . The method of claim 13 , wherein the photo detector array is a charge coupled device (CCD) or a CMOS (complementary metal oxide semiconductor) camera sensor.

15 . The method of any one of claims 1 - 14 , comprising using an optical conduit to communicate light in at least one direction selected from toward the sample and away from the sample.

16 . The method of any of claims 1 - 15 , wherein the optical conduit to communicate light in at least one direction selected from toward the sample and away from the sample is selected from a fiber, an arrangement of fibers, a fiber bundle, a rigid lens, an arrangement of rigid lenses, a gradient index (GRIN) lens, or an arrangement of GRIN lenses.

17 . The method of any of claims 1 - 16 , wherein the same optical conduit communicates light toward the sample and away from the sample.

18 . The method of any of claims 1 - 17 , wherein different components of the same optical conduit communicates light toward the sample and away from the sample.

19 . The method of any one of claims 1 - 18 , wherein the axis of illumination of the sample with the first light source and the axis of detection of light originating from the first light source are displaced by from about 0.2 mm to about 10 mm.

20 . The method of any one of claims 3 - 19 , wherein the axis of illumination of the sample with the second light source and the axis of detection of light originating from the second light source are displaced by from about 0.2 mm to about 10 mm.

21 . The method of any one of claims 1 - 20 , wherein the object plane of the target region is from the surface to about 300 μm below the surface of the sample.

22 . The method of any one of claims 1 - 21 , wherein the lateral resolution of the image is from about 0.1 μm to about 10 μm.

23 . The method of any one of claims 3 - 22 , comprising detecting the first and second images during first and second non-overlapping time intervals.

24 . The method of any one of claims 3 - 22 , comprising detecting the first and second images during first and second overlapping time intervals.

25 . The method of claim 24 , wherein the first and second light sources illuminate the sample with light of different distinguishable wavelengths.

26 . The method of claim 25 , wherein the images of different distinguishable wavelengths are separated by a wavelength separator and directed onto separate camera sensors.

27 . The method of claim 25 , wherein the images of different distinguishable wavelengths are separated by a wavelength separator and directed onto different portions of a same camera sensor.

28 . The method of claim 24 , wherein the first and second light sources illuminate the sample with orthogonally polarized light.

29 . The method of claim 28 , wherein the images of orthogonal polarization are separated by a polarization separator and directed onto separate camera sensors.

30 . The method of claim 28 , wherein the images of orthogonal polarization are separated by a polarization separator and directed onto different portions of a same camera sensor.

31 . The method of any one of claims 4 - 30 , wherein the difference image is axially resolved.

32 . The method of any one of claims 1 - 31 , further comprising obtaining a series of two or more images and combining the images to provide a composite image larger than the field of view a single image.

33 . The method of any one of claims 1 - 32 , comprising creating a phase contrast image of gastrointestinal tissue and examining the tissue to assess at least one of the presence and the absence of indicators of a disease.

34 . The method of claim 33 , wherein the gastrointestinal tissue is colonic mucosa disease is at least one of hyperplasia and adenomatous changes.

35 . The method of any one of claims 1 - 32 , comprising creating a phase contrast image of lung tissue and examining the tissue to assess at least one of the presence and the absence of at least one indicator of a disease.

36 .

Assignees

• Univ Boston

Inventors

• Mertz Jerome Charles
• Ford Timothy Nehiley
• Chu Kengyeh Ken

Classifications

• G06T2207/20208

  High dynamic range [HDR] image processing · CPC title

• A61B1/00172

  with means for scanning · CPC title

• G01N21/4795

  spatially resolved investigating of object in scattering medium (in vivo A61B) · CPC title

• G01N21/27

  using photo-electric detection (G01N21/31 takes precedence){; circuits for computing concentration (logarithmic circuits G06G7/24; photometric circuits in general G01J)} · CPC title

• G02B21/06

  Means for illuminating specimens · CPC title