Iterative estimation of coherent-scattering profiles from given positions by use of a single-direction beam.

The coherent-scattering distribution is useful for characterization of materials in the medical field, and obtaining this information from a given position in the object is a useful new diagnostic approach. We propose a simpler geometric approach, which requires only a single-direction X-ray beam with no collimator in front of the detector. This method iteratively estimates coherent-scattering profiles from given positions along the beam path, based on the projections positioned at different object-to-detector distances. We confirmed the proposed calculation algorithm by numerical simulation and performed a simple experiment including attenuation correction. The accuracy of matching with the original profiles was dependent on the number of iterations, the distance between the first and second detectors, the distance between two objects, and the shape of the scattering profile. Whereas multiple scattering was the main problem in the experiment, the calculated scattering profiles matched well with the original profile. This technique indicates the feasibility of developing a coherent-scatter imaging system.