Real-time photoacoustic microscopy for rapid diagnosis of pathology

A photoacoustic microscopy system for intraoperative pathology imaging, the system comprising:

• a pulsed laser source that generates an ultraviolet laser beam;
• a polygon scanner having a plurality of reflective facets, wherein the polygon scanner deflects the ultraviolet laser beam along a fast axis;
• a telephoto lens assembly that receives the deflected ultraviolet laser beam from the polygon scanner, wherein the telephoto lens assembly comprising a positive lens group and a negative lens group that expand the deflected ultraviolet laser beam;
• an objective lens configured to focus the expanded ultraviolet laser beam onto a tissue sample;
• a motorized stage having at least two axes of motion, including at least one axis of an imaging plane and an axis orthogonal to the imaging plane, wherein the motorized stage is configured to support the tissue sample and configured to translate the tissue sample along the at least one axis of the imaging plane and vertically along the orthogonal axis;
• an ultrasound transducer that is configured to detect photoacoustic signals generated from the tissue sample in response to illumination by the ultraviolet laser beam;
• a data acquisition device that digitizes the photoacoustic signals;
• and
• a controller that:
• controls the motorized stage and is configured to perform a rapid pre-scan of the tissue sample;
• extracts surface topology data from the photoacoustic signals acquired during the pre-scan to generate a contour map representing variations in surface height of the tissue sample;
• synchronizes operation of the pulsed laser source, the polygon scanner, the motorized stage, and the data acquisition device during imaging;
• and
• controls the motorized stage and is configured to dynamically adjust a position of the tissue sample vertically along the orthogonal axis during a high-resolution imaging scan based on the contour map.