Spectral encoding could allow confocal in vivo imaging of human tissue

Gary J. Tearney and colleagues at Wellman Laboratories of Photomedicine, Massachusetts General Hospital (Boston, MA), have demonstrated a submicrometer-resolution scanning confocal microscope that could be miniaturized and incorporated into an endoscope. The researchers suggest that, with improvements, the spectrally encoded confocal microscope (SECM) could be implemented for in vivo diagnostic imaging of human internal tissue.

Spectral encoding could allow confocal in vivo imaging of human tissue

Gary J. Tearney and colleagues at Wellman Laboratories of Photomedicine, Massachusetts General Hospital (Boston, MA), have demonstrated a submicrometer-resolution scanning confocal microscope that could be miniaturized and incorporated into an endoscope. The researchers suggest that, with improvements, the spectrally encoded confocal microscope (SECM) could be implemented for in vivo diagnostic imaging of human internal tissue.

The instrument encodes sample remittance as a function of spatial location using a diffractive optical element to illuminate distinct spatial locations on the sample specimen with different wavelengths of light. The wavelength-division-multiplexed information is transmitted along a single-mode fiber and demultiplexed external to the probe by heterodyne Fourier-transform spectroscopy. The light source is a quasi-monochromatic diode producing 47 µW with a center wavelength at 940 nm and a bandwidth of 75 nm. Because this arrangement does not require fast spatial scanning within the probe, the instrument can be miniaturized. And, according to Tearney, decoding the feedback away from the probe may allow the SECM to provide frame rates compatible with in vivo imaging of human tissue, free of motion artifacts, with equipment compact enough to fit into a small-diameter catheter or endoscope.

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