The multi-frame image acquisition is performed during a continuous rotation of the X-Ray Positioner, starting from the initial incidence and acquiring frames in a given angular direction at variable angular steps and variable time intervals.
Typically such rotational acquisition is performed with the purpose of further 3D reconstruction. The rotation axis is not necessarily the patient head-feet direction, which may lead to images where the patient is not heads-up oriented.
There may be one or more rotations of the X-Ray Positioner during the same image acquisition, performed by following different patterns, such as:
One rotation for non-subtracted angiography;
Two rotations in the same or in opposite angular directions, for subtracted angiography;
Several rotations at different time intervals for cardiac triggered acquisitions.