Figure 2. Wide-area surface microscopy of fresh human prostate.

a, In preparation for post-operative pathological evaluation, radical prostatectomy specimens are grossly processed by manually cutting the organ into cross-sectional slices (3 to 5 mm in thick). b, A photograph of a fresh prostate slice (3.1 × 3.5 × 0.4 cm) imaged with the open-top light-sheet microscope. c, The tissues are stained with acridine orange for 20 sec and then imaged at a speed of v = 50 sec/cm², which provides a vertical field of view of h = 320 μm to accommodate for any surface irregularities and tilting errors. A horizontal (en face) 2D “section” from the 3D dataset is shown on the top left, prior to surface extraction, where regions of defocus and incomplete imaging are seen (inset arrows). On the bottom right, the irregular surface of the large specimen has been digitally extracted from the 3D dataset to provide a comprehensive image of the surface. d, A depth profile of the tissue surface, along the dashed pink line, reveals significant surface irregularities (up to 200 μm) as well as a slight tilt in the glass-plate sample holder (2 μm/mm or 0.2% slope). e, A histogram of the tissue surface depth from all N=25 prostate slices imaged in this study (average and 95% confidence intervals, CI). For illustrative purposes, the depth of focus is indicated for both a conventional single-axis microscope and our open-top light-sheet microscope. f, Moderate- and high-magnification images of normal prostate glands, where a layer of both basal and epithelial cells is observed (inset arrows). A corresponding H&E histology image is shown on the right. g, A region with benign prostate (left) transitioning into prostate adenocarcinoma (right), which exhibits a crowding of glands with a single epithelial cell layer (inset arrow). h, High-grade prostate intraepithelial neoplasia, displaying stratified nuclei and tufted projections into the lumen. A corresponding H&E histology image is shown on the right.