Abstract: A control system for the x-ray tube high voltage supply in an x-ray diagnostic installation has a switching device for switching between two circuits for providing an actual value to the high voltage generator for regulating the output thereof. The first circuit determines an actual value from a voltage divider connected to two high voltage generators in series. The other circuit includes radiation detectors, one of which may be filtered, which provide an indication of the radiation quality and are used to modulate an incoming actual value signal. Operation of the switching device is controlled by a ramp generator such that in the range of lower x-ray tube high voltages, which occur immediately after switching on the x-ray tube, control is undertaken on the basis of the actual value of the x-ray tube high voltage through the voltage divider, and upon the attainment of a higher x-ray tube high voltage a switch over occurs such that control of the high voltage is effected by the radiation-detecting circuit.

Abstract: In an exemplary embodiment including a dose rate control device for fluoroscopy and an automatic control for x-ray exposures, a memory device is provided in which a respective pair of values for the x-ray tube output and for the exposure time is stored for each patient transparency and further exposure values. Further, a detector is provided which changes the pair of values called up when the exposure time switched by the exposure control deviates from the exposure time called up by a prescribed measure.

Abstract: In an exemplary embodiment, an X-ray image intensifier and a camera for photographing the X-ray image intensifier-output image, an automatic exposure timer which includes an integrator for detection of the light quantity per image and a threshold value switch for shut off of the X-ray tube upon attainment of a setpoint light quantity. The threshold value switch possesses a control input for determining the switch-off threshold which is connected to a correction circuit for comparing the actual value and the setpoint value of the light quantity and which so determines the threshold that the actual value is adapted to the setpoint value. The afterglow of the X-ray image intensifier following the occurrence of a switch-off signal is thereby compensated.

Abstract: An exemplary embodiment comprises an image intensifier television chain, a device for dose output regulation during fluoroscopy, a function generator for determining the exposure voltage from the fluoroscopic voltage, and an automatic exposure control which keeps the integral of the light output from image intensifier per exposure constant. A manual selector is present by which the exposure voltage can be set, e.g. at any whole number value between 50 kV and 125 kV independently of the automatic circuit for setting this voltage. The automatic exposure control is designed in such manner that, given the manual setting of the exposure voltage, the function generator changes the x-ray tube current given constant exposure time for patient thicknesses that lie below a lower value and, for patient thicknesses above this lower value, changes the exposure time given constant x-ray tube current.