Characterization and correction of temporal artifacts in CT

Image artifacts, caused by a temporally delayed response of a computed tomography (CT) detector, were investigated. To study its consequences, a computer model for a standard third generation CT scanner was devised and simulations were carried out. Resulting image artifacts were studied for various voxel-based and mathematical phantoms using three time constants, which characterize the delayed signal responses of different detector configurations. Furthermore, a theory was developed to understand temporal artifacts in reconstructed images. A filter function was derived, which compensates for temporal artifacts. For a given phantom, simulations and theory demonstrate that artifacts scale with the time constant, characteristic for the detector, and the angular speed of the scanner.