Multi-slice spiral CT simulator for dynamic cardio-pulmonary studies.

We've developed a Multi-slice Spiral CT Simulator modeling the acquisition process of a real tomograph over a (4D MCAT) of the human thorax. The simulator allows us to visually characterize a 4-dimensional phantom artifacts due to insufficient temporal sampling and "a priori" evaluate the quality of the images obtained in cardio-pulmonary studies (both with single-/multi-slice and ECG gated acquisition processes). The simulating environment allows both for conventional and spiral scanning modes and includes a model of noise in the acquisition process. In case of spiral scanning, reconstruction facilities include longitudinal interpolation methods (360LI and 180LI both for single and multi-slice). Then. the reconstruction of the section is performed through FBP. The reconstructed images/volumes are affected by distortion due to insufficient temporal sampling of the moving object. The developed simulating environment allows us to investigate the nature of the distortion characterizing it qualitatively and quantitatively (using, for example. Herman's measures). Much of our work is focused on the determination of adequate temporal sampling and sinogram regularization techniques. At the moment. the simulator model is limited to the case of multi-slice tomograph. being planned as a next step of development the extension to cone beam or area detectors.