Simultaneous multi planar microscope imaging enables parallel computation of autofocus for high-sped image cytometry. Although image cytometry exhibits many potential advantages over flow cytometry, substantially slower speed has limited use to fewer applications. In commercial image cytometry instruments, long scanning times have typically been circumvented by identification of small areas of interest during high speed, low resolution scans for subsequent analysis at high resolution. This two-pass strategy of analyzing only a few cells at high resolution is a disadvantage and often cannot be used at all where dim fluorescence demands higher numerical aperture (NA) objectives. Continuous stage motion synchronized with line array or time-delay-and-integrate (TDI) CCD image acquisition is capable of increasing scan speed by an order of magnitude or more, but until recently lacked the autofocus required for higher resolution objectives where depth of field is about the thickness of a cell monolayer. Here we describe an improved design for simultaneous multi planar acquisition and on-the-fly autofocus. This new system replaces more complicated and less light efficient fiberoptic imaging bundles with beamsplitters and mirrors. This new image-splitting design also enables addition of magnification correction optics not easily added to the earlier fiberoptic version. The result is a simplified, high sensitivity, magnification-matched, parallel multi planar acquisition module containing an array of CCD sensors for high-speed focus tracking and 3D imaging.
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