FAST TOMOSYNTHESIS SCANNER APPARATUS AND CT-BASED METHOD BASED ON ROTATIONAL STEP-AND-SHOOT IMAGE ACQUISITION WITHOUT FOCAL SPOT MOTION DURING CONTINUOUS TUBE MOVEMENT FOR USE IN CONE-BEAM VOLUME CT MAMMOGRAPHY IMAGING

摘要

The present invention generally refers to computed tomography (CT) based imaging systems and, more particularly, to a fast 3D tomosynthesis scanner appa-ratus and CT-based method without focal spot motion during continuous tube move-ment around an object of interest (O) or tissue region (M) to be examined (herein also referred to as “object”), which may advantageously be used in cone-beam volume CT mammography imaging so as to avoid motion artifacts and blurring effects. According to the present invention, said 3D tomosynthesis scanner apparatus is adapted to perform a rotational step-and-shoot image acquisition procedure for acquiring a set of 2D projec-tion images during a continuous rotational movement of an X-ray tube (101) in an azi-muthal direction (+φ ) along an arc segment of a circular trajectory when rotating around said object (O, M) and subjecting these 2D projection images to a 3D recon-struction procedure. According to the present invention, it is foreseen that, during the image acquisition time for each 2D projection image, the focal spot on the X-ray tube’s anode is moved in an opposite direction (–φ ) from a start position (bs) to an end posi-tion (be) with respect to the rotary X-ray tube’s housing such that the azimuthal path dis-tance (Δb) covered by the X-ray tube (101) due to the continuous rotational tube move-ment during this time is compensated. The 3D tomosynthesis scanner further comprises a mechanism for switching the focal spot on the X-ray tube’s anode back to its start po-sition (bs) with respect to said tube housing before starting a new image acquisition process for acquiring image data of a next 2D projection image. The superposition of the focal spot movement with respect to the tube housing and the continuous rotational movement of the X-ray tube (101) along said arc segment results in a stationary focal spot position relative to the object (O, M) and a stationary X-ray detector (104) diametr-ically oppositely arranged to the X-ray tube (101) with respect to said object (O) for each of the individual 2D projection images. (Fig. 3)