1. An imaging method for imaging a region of investigation of an object, comprising the steps of: generating an energy input beam with an energy beam source; irradiating the region of investigation with energy input beam components of the energy input beam along a plurality of projection directions, the energy input beam components being formed with a frame mask being arranged between the energy input beam and the object and including frame mask window; measuring first integrated attenuation values of the energy input beam components with an outer detector device arranged outside the frame mask; measuring second integrated attenuation values of the energy input beam components with a frame mask detector device being arranged on an inner surface of the frame mask; and reconstructing an image of the region of investigation based on the first and second integrated attenuation values.