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High speed optical coherence microscopy with autofocus adjustment and a miniaturized endoscopic imaging probe.

Aguirre AD, Sawinski J, Huang SW, Zhou C, Denk W, Fujimoto JG - Opt Express (2010)

Bottom Line: The system utilized a novel polarization compensation method to combat wavelength dependent source polarization and achieve broadband electro-optic phase modulation compatible with ultrahigh axial resolution.In addition, the system incorporated an auto-focusing feature that enables precise, near real-time alignment of the confocal and coherence gates in tissue, allowing user-friendly optimization of image quality during the imaging procedure.Ex vivo cellular images of human esophagus, colon, and cervix as well as in vivo results from human skin are presented.

View Article: PubMed Central - PubMed

Affiliation: Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA.

ABSTRACT
Optical coherence microscopy (OCM) is a promising technique for high resolution cellular imaging in human tissues. An OCM system for high-speed en face cellular resolution imaging was developed at 1060 nm wavelength at frame rates up to 5 Hz with resolutions of < 4 microm axial and < 2 microm transverse. The system utilized a novel polarization compensation method to combat wavelength dependent source polarization and achieve broadband electro-optic phase modulation compatible with ultrahigh axial resolution. In addition, the system incorporated an auto-focusing feature that enables precise, near real-time alignment of the confocal and coherence gates in tissue, allowing user-friendly optimization of image quality during the imaging procedure. Ex vivo cellular images of human esophagus, colon, and cervix as well as in vivo results from human skin are presented. Finally, the system design is demonstrated with a miniaturized piezoelectric fiber-scanning probe which can be adapted for laparoscopic and endoscopic imaging applications.

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Measurement of confocal gate position in scattering tissue using coherence ranging. The OCM depth scanner was used to acquire a lateral priority cross-sectional image, which clearly shows the restricted depth of field resulting from high NA focusing (A). Averaging across lateral scans produced an average depth response, which is a measure of the confocal axial response in scattering tissue (B). Images obtained with the coherence and confocal gates misaligned (C,F and E,H) appear out of focus compared to the image obtained with the gates precisely aligned (D,G). Scale bars, 100 µm.
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g007: Measurement of confocal gate position in scattering tissue using coherence ranging. The OCM depth scanner was used to acquire a lateral priority cross-sectional image, which clearly shows the restricted depth of field resulting from high NA focusing (A). Averaging across lateral scans produced an average depth response, which is a measure of the confocal axial response in scattering tissue (B). Images obtained with the coherence and confocal gates misaligned (C,F and E,H) appear out of focus compared to the image obtained with the gates precisely aligned (D,G). Scale bars, 100 µm.

Mentions: One strategy for OCM is to use a passive autofocusing scheme where the en face image sharpness is optimized while iteratively adjusting the reference path length. Another approach, analogous to active autofocusing, is to use the path scanner to perform coherence depth ranging as in cross-sectional OCT imaging. This method can be significantly faster than the passive approach because it allows direct location of the position of the confocal gate without iterative acquisition of multiple image frames. Figure 7Fig. 7


High speed optical coherence microscopy with autofocus adjustment and a miniaturized endoscopic imaging probe.

Aguirre AD, Sawinski J, Huang SW, Zhou C, Denk W, Fujimoto JG - Opt Express (2010)

Measurement of confocal gate position in scattering tissue using coherence ranging. The OCM depth scanner was used to acquire a lateral priority cross-sectional image, which clearly shows the restricted depth of field resulting from high NA focusing (A). Averaging across lateral scans produced an average depth response, which is a measure of the confocal axial response in scattering tissue (B). Images obtained with the coherence and confocal gates misaligned (C,F and E,H) appear out of focus compared to the image obtained with the gates precisely aligned (D,G). Scale bars, 100 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2908909&req=5

g007: Measurement of confocal gate position in scattering tissue using coherence ranging. The OCM depth scanner was used to acquire a lateral priority cross-sectional image, which clearly shows the restricted depth of field resulting from high NA focusing (A). Averaging across lateral scans produced an average depth response, which is a measure of the confocal axial response in scattering tissue (B). Images obtained with the coherence and confocal gates misaligned (C,F and E,H) appear out of focus compared to the image obtained with the gates precisely aligned (D,G). Scale bars, 100 µm.
Mentions: One strategy for OCM is to use a passive autofocusing scheme where the en face image sharpness is optimized while iteratively adjusting the reference path length. Another approach, analogous to active autofocusing, is to use the path scanner to perform coherence depth ranging as in cross-sectional OCT imaging. This method can be significantly faster than the passive approach because it allows direct location of the position of the confocal gate without iterative acquisition of multiple image frames. Figure 7Fig. 7

Bottom Line: The system utilized a novel polarization compensation method to combat wavelength dependent source polarization and achieve broadband electro-optic phase modulation compatible with ultrahigh axial resolution.In addition, the system incorporated an auto-focusing feature that enables precise, near real-time alignment of the confocal and coherence gates in tissue, allowing user-friendly optimization of image quality during the imaging procedure.Ex vivo cellular images of human esophagus, colon, and cervix as well as in vivo results from human skin are presented.

View Article: PubMed Central - PubMed

Affiliation: Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA.

ABSTRACT
Optical coherence microscopy (OCM) is a promising technique for high resolution cellular imaging in human tissues. An OCM system for high-speed en face cellular resolution imaging was developed at 1060 nm wavelength at frame rates up to 5 Hz with resolutions of < 4 microm axial and < 2 microm transverse. The system utilized a novel polarization compensation method to combat wavelength dependent source polarization and achieve broadband electro-optic phase modulation compatible with ultrahigh axial resolution. In addition, the system incorporated an auto-focusing feature that enables precise, near real-time alignment of the confocal and coherence gates in tissue, allowing user-friendly optimization of image quality during the imaging procedure. Ex vivo cellular images of human esophagus, colon, and cervix as well as in vivo results from human skin are presented. Finally, the system design is demonstrated with a miniaturized piezoelectric fiber-scanning probe which can be adapted for laparoscopic and endoscopic imaging applications.

Show MeSH