Measuring physical density with X-ray computed tomography

Abstract

X-ray computed tomography (CT) can quantify variations in material density. However, little practical information concerning accurate translation of CT numbers (an approximation of the material's linear attenuation coefficient) into mass density exists. We describe our development of this methodology. Issues addressed include the physics of mapping CT density to mass density; development and scanning of density standards; post-reconstruction filtering to reduce the effects of quantum noise; and segmentation of the object data from the surrounding medium. Examples of our use of this procedure in studying density gradients during powder pressing and firing are given. © 1997 Elsevier Science Ltd. All rights reserved.