Efficient projection model for blobs in motion-compensated iterative cone-beam CT

We present a three-dimensional method to reconstruct moving objects from cone-beam X-ray projections using an iterative reconstruction algorithm and a given motion vector field. For the image representation, adapted blobs are used which can be implemented efficiently as basis functions. In the case of a divergent motion vector field, blob volume change has to be taken into account in the forward-projections. An efficient method to calculate the line integral through the adapted blobs is proposed, and in two simulated data sets it is shown that this method prevents blurring and streak artifacts.