X-ray diagnostic system with automatic control of radiation exposure

摘要

An x-ray diagnostic system has a control loop with a first regulating stage connected to a first radiation detector disposed after the x-ray image intensifier, the first regulating stage controlling at least one radiographic exposure value in dependence upon the output signal of the detector, and a second radiation detector which is disposed proximate the x-ray tube for supplying an output signal to a second regulating stage in the control loop, the second regulating stage having a memory for storing a signal which is dependent upon the dose rate for the last image. The memory signal is utilized as a reference signal for the second regulating stage. If the operator of the x-ray system determines that the contrast in the diagnostically relevant image region is becoming too great, the operator can switch from control of the system by the first regulating stage to control by the second regulating stage.