OCT-guided integrated multimodal photoacoustic microscopy for fast scanning speed and large scanning area (Conference Presentation)

Acquiring more comprehensive information of biological samples requires imaging multiple optical contrasts, which is not typically offered by a single imaging modality. Different optical imaging modalities providing absorption, scattering and molecular information of biological tissues, have been developed and used in many biomedical investigations in the past decades. Large field-of-view (FOV) and high imaging speed are desired for all these imaging techniques. Uneven surface of a sample can lead to uneven depth focus, resulting in images with non-uniform resolution and signal intensity especially in large FOV imaging. Here, we report on our newly developed OCT-guided opto-mechanical scanning multimodal imaging system with the capability of dynamic focusing. By taking advantage of the depth resolving capability of OCT, we developed a novel OCT-guided surface contour scanning methodology for dynamic focusing during entire scanning of an uneven sample. To achieve this, we combined a fully motorized three-dimensional mechanical stage with an X-Y galvanometer optical scanner which made the imaging system suitable for fast scanning of large area. This imaging system integrates photoacoustic microscopy (PAM), optical coherence tomography (OCT) and fluorescence microscopy in one platform providing absorption, structural and molecular information of biological tissue, respectively. Phantom, ex vivo, and in vivo imaging studies demonstrated the performance of the OCT-guided surface contour scanning scheme as well as the capability of our multimodal imaging system to provide comprehensive microscopic information on biological tissues with large FOV and fast scanning. We believe this novel multimodal imaging system has promising potential for preclinical research and clinical practice in the near future. Keywords: Multimodal optical imaging, optical microscopy, photoacoustic microscopy, optical coherence tomography, fluorescence microscopy, dynamic focusing