Abstract: An x-ray video system for the transillumination of an examination subject has an x-ray system which generates a transillumination image of a patient using an x-ray beam having a central ray, a diaphragm for gating the x-ray beam which has a number of plates, each moveable relative to the central ray, a signal generator associated with each plate which generates a signal corresponding to the position of the associated plate relative to the central ray, a mixer for combining the plate position signals with the transillumination image, and a display which generates the transillumination image with the position signals mixed therewith in the form of marks on the transillumination image.