Extension of the cone-beam CT field-of-view using two short scans with displaced centers of rotation

A robotic cone-beam computed tomography (CT) scanner has inherent advantages. In particular, it enables source and detector trajectories capable of extending the field-of-view (FOV) of the reconstructed CT images, where the FOV is defined as the region in the source trajectory plane for which all ray lines are acquired (at any position and direction in this plane). Previous extensions of the FOV used an offset detector or a displaced center of rotation and a single full 360◦ scan. However, due to limitations in the conventional range of motion inside the treatment room to avoid collisions, some systems can only perform short scans. This paper investigates a new approach to FOV extension for an existing system by adapting the FOV extension to two complementary short scans with displaced centers of rotation. We validate this approach on numerical simulations of the Forbild thorax phantom.