ITERATIVE IMAGE RECONSTRUCTION OF A MOVING OBJECT FROM PROJECTION DATA

摘要

Iterative methods for reconstructing an image sequence of a moving object based on projection data usually require a high computationally effort. According to embodiments of the present invention there is provided such a method wherein a first image representing the object at a first phase is used as an initial image for iteratively reconstructing a second image at a second phase. A first gating function is assigned to the first phase, a second gating function is assigned to the second phase. When executing a first iteration for reconstructing the second image only projection data corresponding to a non- overlapping part of the two gating functions are used. For executing further iterations the amount of projection data corresponding to the overlapping part of the two gating functions may be gradually increased. Therefore, for all further but the last iteration the computationally effort is significantly reduced. However, this low computationally expense has no negative impact on the quality of the finally reconstructed second image because the method benefits from the fact that the first image was used as the initial image for iteratively reconstructing the second image.