SKM, Inc. of Austin, Texas has developed a computerized tomography system suitable for the examination of dense materials, especially concrete and steel. The tomographs of test specimenns (six-inch diameter piers of various cement aggregate mix), produced by the prototype scanner, show aggreate or voids down to 1 mm in diameter and cracks less than 1 mm wide as well as accurately reconstructing the location and density of reinforcement bars and the density of the background paste and aggregate. The SKM scanner uses a gamma-ray source to provide photons of sufficient energy to penetrate dense materials. The first series of scans was done with a 1.6 Curie Cesium-137 source, and tests are planned with Iridium-192 and Cobalt-60. Plastic scintillator strips detect and count each transmitted photon, with a detection efficiency of over 80per thousand. Scans of a few minutes should be typical in a field application although scan time depends on several factors. It is invisioned that the technique will find extensive application in quality control and in wear and failure analysis for pipes, concrete piers, and beams.