1. A scanner for imaging optical properties of a three-dimensional object ranging in size from a volume of about 1 cm 3 to a cylinder having a radius of about 25 cm and a height of about 25 cm, said scanner comprised of: a highly collimated light source emitting a light beam transmitted through said object; a first photoreceiver, for measuring the attenuation of said light beam by said object; a first and second rotating mirror; a first converging lens; a tank containing refractive index matching liquid in which the object is immersed; a means to rotate said object about an axis substantially perpendicular to the optical axis; a computer for controlling the movement of said rotating mirrors, for controlling the orientation of the object with respect to the scanning beam, and for calculating said optical properties; wherein said imaging comprises forming a series of two-dimensional projections by scanning said object in a two-dimensional raster pattern, changing the orientation of the object with respect to the scanning beam, repeating the scanning and the orientation a plurality of times, employing computerized algorithms to filter the series of projections, and reconstructing a three-dimensional image using computerized tomographic techniques.