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.
Spies
L
L
Philips Research Laboratories, D-52066 Aachen, Germany. lothar.spies@philips.com
Luhta
R
R
D000465:Algorithms; D016477:Artifacts; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*