A scatter correction using thickness iteration in dual-energy radiography

In dual-energy radiography with area detectors, a scattered signal causes dominant error in the separation of different materials. Several methods for scatter correction in dual energy radiography have been suggested, yielding improved results. Such methods, however, require additional lead blocks or detectors, and additional exposures to estimate the scatter fraction for every correction. In the present study we suggest a scatter correction method that uses a database of fractions and distributions of the scattered radiation. To verify the feasibility of this method we conducted a MCNP simulation for a two-material problem, aluminum and water. The generation of the scatter information for different thicknesses of an aluminum-water phantom has been simulated. Based on the uncorrected signals, the thickness of each material can be calculated by a conventional dual-energy algorithm. The scatter information of the corresponding thickness from the database, a look-up table, is then used to correct the original signals. The iteration of this scatter correction reduced relative-thickness error from 32% to 3.4% in aluminum, and from 41% to 2.8% in water. The proposed scatter correction method can be applied to two-material dual-energy radiography such as mammography, contrast imaging, and industrial inspections.