Simulated Motion Artefact in Computed Tomography

We propose a simulation framework to simulate the computed tomography acquisition process. It includes five components: anatomic data, respiration modelling, automatic parametrisation, X-ray simulation, and tomography reconstruction. It is used to generate motion artefacts in reconstructed CT volumes. Our framework can be used to evaluate CT reconstruction algorithm with motion artefact correction in a controlled environment. 1 Respiration Modelling Anatomical data from 4D CT scans is segmented to provide polygon meshes. The motion due to the respiration is computed in realtime using three different methods [4]. The rib cage motion is simulated by an articulated model of the rib rotations. The diaphragm behaviour is simulated by a deformable model with an intrinsic force to apply contraction and relaxation on its central tendon. The liver behaviour is simulated by a deformable model where boundary conditions are applied by both the rib cage and the diaphragm motion. The 3D Chainmail method is used to deform soft-tissues in real-time [1]. The model includes many parameters, which are automatically tuned using artificial evolution [3]. 2 X-ray Simulation In [2] we proposed a method to compute the X-ray attenuation law on the GPU. The code has been revised and a quantitative validation has been performed. It shows the accuracy of results produced with our implementation. The result is gVirtualXRay, Virtual X-Ray Imaging Library on GPU, an OpenSource Library available at http://gvirtualxray.sourceforge.net/. Fig. 1 shows the virtual scanning environment. The geometry of the virtual patient is positioned in the