Patent Number: 052609847
Section: summary

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to an x-ray diagnostics installation of the type having a primary radiation diaphragm disposed in the beam path of an x-ray tube, and control means for setting the position of the primary radiation diaphragm. 2. Description of the Prior Art In x-ray diagnostics systems which result in the production of an x-ray image and/or a visible image corresponding to the x-ray image, the position of the primary radiation diaphragm, or the position of beam-interacting elements thereof, is adjustable for various purposes, such as for selecting the contour of the examination region which will appear in the image. For example, a heart contour diaphragm can be used in a so-called depth diaphragm top achieve a primary reduction in the contrast between the mediastinum (heart shadow) and the adjoining lung field for improving the image quality or for avoiding halations (glare) in the video image. The diaphragm can be adjusted to produce a straight contour, concave or convex shapes, or a wedge shape. A primary radiation diaphragm of this type is disclosed in German Patent 1 800 879 for use in an x-ray exanination apparatus, wherein two lamellae can be moved toward and away from each other by actuating keys. The lamellae are mounted on a rotatable carrier, which can be rotated by means of a further operating key. The respective keys which control these different movements are identical, so that mistakes can easily occur. More recently, a joystick has been predominantly used to control the operation of the primary radiation diaphragm as described, for example, in the brochure for the "ANGIOSTAR.RTM.", manufactured by Siemens AG. Pivoting the joystick toward the right or the left respectively causes an introduction of the diaphragm plates into the image, or a withdrawal of the diaphragm plates from the image. Movement of the joystick toward the front or rear results in a rotation of the entire diaphragm. Such operation of the joystick, however, is not ergonometric, and mistakes again can easily occur. SUMMARY OF THE INVENTION It is an object of the present invention to provide an x-ray diagnostics installation having a primary radiation diaphragm which is operable in a simple and ergonometric manner. The above object is achieved in accordance with the principles of the present invention in an x-ray diagnostics installation having a control unit for the primary radiation diaphragm with an operator-manipulable setting element which controls the control unit so that the type of motion of the setting element corresponds to the type of motion which the primary radiation diaphragm is caused to undergo by the operation of the setting element. The desired position of the primary radiation diaphragm can thus be set in a simple manner, by operating the setting element in a way which corresponds to the desired motion of the primary radiation diaphragm. Mistakes in the operation of the primary radiation diaphragm are thereby reduced. Preferably the setting element is in the form of an operating lever provided with a cap, the operating lever being pivotable in all directions in the manner of a joystick, and being rotatable by means of the cap, with a rotary motion of the setting element effecting a rotation of the primary radiation diaphragm, and a pivoting of the setting element effecting movement of the primary radiation diaphragm in a direction corresponding to the pivoting direction. As a result of movement of the operating lever in one of the directions, the primary radiation diaphragm will move in the same direction, and a rotation of the primary radiation diaphragm is achieved by rotating the cap. By making the motion of the primary radiation diaphragm in the video image coincide with the motion of the setting element, it is not necessary for the operating personnel to "reinterpret" the motion of the diaphragm as correlated with the operation of the control means by the setting element. The visibility of the primary radiation diaphragm in the video image is enhanced in an embodiment wherein the control means is connected to a processing circuit which causes a line corresponding to the contour of the primary radiation diaphragm (or a beam-interacting element thereof), to be mixed in the video image upon actuation of the setting element. The radiation load on the attending personnel can be reduced by connecting the control means to the high-voltage generator which feeds the x-ray tube, with the control means reducing the dose of the x-ray generator upon actuation of the setting element. The setting can then take place with a reduced radiation dose, since a qualitatively high-grade x-ray image is not required during the setting. Further setting functions can be combined with the above-described embodiments by mounting the operating lever so that it can be pressed and/or pulled. For example, adjustment of an iris diaphragm arranged in an optics system can be effected in this manner with pressing/pulling of the operating lever causing opening/closing of the iris diaphragm. The position of the evaluation dominant can be taken into consideration when adjusting the primray radiation diaphragm in an embodiment wherein the position of the evaluation dominant is mixed in the video image when the setting element is actuated.