An apparatus for spatial modulation of an x-ray beam has a number of planar attenuation elements for x-ray radiation that are disposed in a grid on a carrier and can be pivoted or tilted by a piezoelectric actuator, independently of one another, between at least two positions. One or more sensors with which a piezoelectrically-caused length and/or width and/or position change of the piezoelectrically influenced regions can be detected, are arranged on piezoelectrically influenced regions of the attenuation elements or the actuators. A significant dose reduction and/or dynamic adjustment thereof can be achieved with the apparatus by image adaptation in many areas of x-ray imaging, since a precise determination of the position of each attenuation element in real time is enabled.