Integrated fluorescence confocal and spectral-domain optical coherence tomography microendoscope

Optical biopsies are aimed at providing fast and thorough screening of biological tissues in vivo. Disease diagnosis is based on the morphological structures and biochemical features of tissues that can be sampled in situ with high resolution. Some optical screening techniques, such as fluorescence confocal microendoscopy, provide a limited imaging depth due to the shallow penetration of visible light. Despite confocal microendoscopy's high resolution and image quality, morphological changes that occur deeper in the tissue cannot be detected. Other imaging techniques, such as optical coherence tomography (OCT), are able to obtain information at greater depth into tissue. A combination of fluorescence confocal and OCT into a single instrument capable of rapidly switching between these modalities, has the potential of providing complementary en face confocal images showing the morphologic features of cells within a surface layer, and cross-sectional OCT images showing tissue microarchitecture below the surface. The concept for this dual system is to utilize the optical train of an existing multi-spectral confocal microendoscope as a spectral-domain OCT system. Progress made on the implementation of this combined dual integrated imaging system is presented. A performance analysis, discussion of the limitations inherent to the use of an imaging fiber bundle, and recent imaging results are presented.