A standard, non-motorized, diagnostic x-ray beam-limiting device that has a fixed size opening. It attaches by means of a slot or base plate to a diagnostic x-ray system tube housing and is used to limit the effects of scattered radiation on image quality and to provide patient protection by eliminating exposure to non-target body areas. An aperture diaphragm consists of a sheet of lead with a hole in the middle. The size and shape of the hole determine the size and shape of the x-ray beam exiting from the x-ray system. Cones and cylinders used for beam collimation are made of lead and attach by means of a base plate to an x-ray tube housing assembly.