PRE-RECONSTRUCTION CALIBRATION, DATA CORRECTION, AND MATERIAL DECOMPOSITION METHOD AND APPARATUS FOR PHOTON-COUNTING SPECTRALLY-RESOLVING X-RAY DETECTORS AND X-RAY IMAGING

摘要

An apparatus and method of processing X-ray projection data obtained using photon-counting detectors and having multiple spectral components. The processing of the projection data includes correcting for nonlinear detector response, where the detector response model includes: pileup, ballistic deficit effects, polar effects, and characteristic X-ray escape. The processing of the projection data also includes a material decomposition mapping the projection data from spectral components into material components corresponding to high-Z and low-Z materials. The material decomposition includes a noise balancing process where the allocation of spectral components between a high-energy and a low-energy combination of spectral components is adjusted such that both high- and low-energy components have signal-to-noise ratios of similar magnitude. For computed tomography (CT) applications, material decomposition can be followed by image reconstruction and then image post-processing and presentation. For non-CT applications, material decomposition can be followed by image post-processing and presentation.

主权项

1. An apparatus to process projection measurements, the apparatus comprising:
processing circuitry configured to
obtain a plurality of datasets, wherein each dataset represents radiation detected by a plurality of detectors, the radiation having been transmitted through an object, wherein each dataset corresponds to a respective energy bin having an energy-detection spectrum that is narrower than a bandwidth of an energy spectrum of the transmitted radiation;calculate a nonlinear detector response of each dataset and subtract the nonlinear detector response from the dataset to obtain a corresponding linear-response dataset; andperform a material decomposition of the plurality of linear-response datasets into a plurality of projection lengths of a first material and a second material.