Recent Technological Developments and Their Influence

At present medical X ray imaging is undergoing major changes triggered by important technological developments. Because of the widespread availability of powerful computers and recent advances in large-area electronics, digital imaging technologies are about to replace the last stronghold of conventional imaging, the radiographic film. An overview is given of the technological principles of the different digital image receptors and their relative merits. Another area where digital acquisition technology has already penetrated into clinical practice is fluoroscopy. Digital snapshots have virtually replaced the spot film. Grid controlled fluoroscopy allows the radiation pulses and thus the dose to be tailored according to the diagnostic question. Dose reductions of up to 80% are possible without loss of diagnostic information. The decoupling of detection and display in digital systems gives new freedom for optimising the imaging parameters but also requires new and appropriate optimisation strategies with respect to image quality and dose.