FOCAL SPOT SIZE MEASUREMENT WITH A MOVABLE EDGE LOCATED IN A BEAM-SHAPING DEVICE

摘要

It is described a method for measuring the sharpness in an X-ray system (100). The measurement is based on a common edge response. An edge device (120) representing the projection device is placed within a beam-shaping device (470). Due to a high geometrical magnification factor the edge response function (241a) and also both an impulse response function (246a) and a modulation transfer function (251a) will predominately depend on the size of the focal spot (112) rather than on a pre- sampling spread function of a detector (130) being used for receiving the X-radiation (117), which has laterally passed the edge device (120).