Shifting an object for complete trajectories in rotational X-ray imaging

摘要

It is described a method for acquiring a series of two-dimensional X-ray attenuation data of an object under examination (310) by means of an X-ray imaging apparatus (100) having a rotatable scanning unit (301). In order to increase the angular range of the scanning unit (301), when a region of interest (HOa) located not in the center of the object (310) is examined the object under examination (310) is shifted such that the region of interest is temporarily positioned outside the center of rotation. By coupling the rotational movement of the scanning unit (301) with the translative movement of the object (310) in a synchronized manner a collision between the scanning unit (301) and the object (310) can be effectively avoided. By employing an automated motorized object table (312) a precise pre-determined movement of the object (310) can be achieved during the data acquisition. By using an appropriate phantom based calibration procedure carried out with the same table movements known three-dimensional reconstruction algorithm can be directly applied in order to generate a three-dimensional representation of the region of interest (110a).