repeatedly pivoting an X-ray arrangement about a pivot axis at a pivoting speed between a first and a second final angular position, by a control device, the X-ray arrangement comprising an X-ray source and an X-ray detector diametrically opposed to each other relative to the pivot axis;

providing a phase signal representing a phasing of an examination object to the control device;

controlling the X-ray arrangement during the pivoting such that the X-ray detector only acquires projections of an iteratively moving examination object during selected time windows in time periods based on the phase signal at a plurality of acquisition points in time and at a plurality of angular positions of the X-ray detector, the examination object arranged in a range of the pivot axis;

transmitting the acquired projections to the control device by the X-ray detector;

storing the transmitted projections and the respective angular positions, by the control device;

assigning to each stored projection a phase information element related to the phasing of the examination object, by the control device;

selecting a phase position, and a maximum allowable deviation therefrom, relative to the phase signal for three dimensional reconstruction of the object;

selecting from the projections those projections having phase positions within the maximum allowable deviation from the selected phase position;

determining for each selected projection the respective angular position of the X-ray detector; and

calculating a three-dimensional reconstruction of the examination object from the selected projections and the determined respective angular positions for use in a medical examination.