1. A method for multi-dimensional imaging of a specimen region, comprising the steps of: a) illuminating the specimen region; b) moving an optical element to scan a focal plane through the thickness of the specimen region at a fixed viewpoint to produce a pseudo-projection image of the specimen onto a two-dimensional array of detectors during a single exposure of the two-dimensional array of detectors, wherein the pseudo-projection image thus formed includes an integration of a range of focal plane images; and c) repeating steps a) and b) for two or more viewpoints to produce a set of pseudo-projection images.