Noise And Material Residues In Dual-Energy Basis Decomposition Radiography

Intervening tissues in projection radiography often seriously interfere with the observability of other low contrast structures. Dual energy techniques resolve this difficulty by removing a selected substance from the image, enhancing the relative contrast of other materials. Undesired materials will remain; these residues, as well as quantum noise, limit the accuracy of material isolation. Parameterizations of the attenuation coefficient lead to simple expressions for the signal-to-noise ratio (SNR) in the dual energy radiograph. The SNR depends on the absorption path, the imaging energies, and the cancelled material. The magnitude of material residue depends only on the atomic numbers and may be an important consideration in the selection and development of new contrast agents.