Reduced field-of-view system for imaging compact embedded structures

A method for generating a tomographic image of an imaged object having a compact structure of a first material contained within a larger body of a second material, the first and second materials having different energy dependent attenuations, comprising the steps of: (a) collimating the width of a radiation beam to substantially equal the width of the compact structure; (b) projecting radiation at a first and second energy level through the compact structure; (c) acquiring a first and second tomographic projection set of attenuations of the x-rays transmitted through the compact structure and intervening portions of the body at the first and second energy at a plurality of angles about the imaged object; (d) combining the first and second tomographic projection sets to produce a third tomographic projection set dependent substantially on the attenuation only of the compact structure; and (e) reconstructing an image of the compact structure from the third tomographic projection set.