Abstract: Degradation in reconstructed medical images is reduced by a method for calibrating a primary decay correction for a radiation detector having a decay curve that can be characterized by a plurality of components having different time constants. The method includes steps of: fitting the decay curve to a sum of a plurality of weighted exponentials having a first set of time constants; applying a correction to a measured response of the detector using a sum of the plurality of weighted exponentials having the first set of time constants to obtain a corrected response; selecting at least one additional exponential time constant dependent upon the corrected response; and fitting the decay curve to a sum of a second plurality of weighted exponentials including the first plurality of time constants and the at least one additional exponential time constant.

Abstract: Methods and apparatus for reducing spectral artifacts in a computed tomography (CT) system are described. In one embodiment, the CT system includes a plurality of multislice detector modules, a detector housing and a collimator adjacent the detector modules. Each detector module is mounted to the detector housing and includes a scintillator array. The collimator includes a plurality of plates that are positioned so that a x-ray beam shadow is centered over gaps in the scintillator array. In operation, the collimator separates the x-ray beams so that the scintillator gaps are protected and the x-ray beams are prevented from projecting through the scintillator array elements along a shortened length path.