Our group at the BC Cancer Research Centre has developed an optical computed-tomography microscope for three-dimensional (3-D) imaging and quantitative analysis of absorption-stained biological samples. The device uses non-ionizing optical radiation for illumination and computed-tomography for 3-D image reconstruction. The optical system consists of a light source, two high-numerical aperture (NA) objective lenses, a sample stage, a CCD detector, and a spatial light modulator that is used for computer-controlled sample illumination. Projections of a specimen are measured at a set of appointed angles within the range of 0 less than or equal to angle less than or equal to 135, which is limited by the NA of the objective. The reconstruction algorithm developed to solve the limited-angle problem employs the reconstruction from a transform-based method as an initial guess for the following iterative reconstruction. 3-D microscopic images of quantitatively absorption-stained cells have been generated with the resolution on the order of 1 micron. Visualization of 3-D tissue structure and architectural and morphological features that can be extracted from the volume to provide pathologists with additional information for diagnostic purposes.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.