Nondestructive inspection of low atomic number media using inelastic photon scattering

The purpose of this study was to examine the potential of using scatter information to evaluate tissue density at selected sites. A method for non-invasively generating profiles of density distribution within an object using Compton scattered X-rays is presented. The Compton scatter method is modified to scan longitudinal sections of composite phantoms and samples of tissue substitute materials. Line scan data are used to describe how the detected count rate changes in response to localized density variations within an extended object. The physical limitations of quantification are discussed, including the effect of attenuation, multiple scatter, and limited spatial resolution. Further, the theory of the method, its performance and results of experimental phantom studies are described. The results presented indicate that the suggested method has the potential for measuring physical density distribution within an object with a spatial resolution of 2 mm and an accuracy of approximately 4% under the circumstances in which attenuation correction is avoided.