[Sensitivity S of film-screen systems and mode of operation of different automatic exposure systems in general practice conditions. II: Automatic exposure systems].

A new method is presented to check several automatic exposure control systems (AEC) for their suitability in radiological image production. It is based on measurements of dose and density with water as an absorbing and scattering medium. The characteristic curves of an AEC can be recorded, i.e., in what way is the dose K in the image receptor plane regulated by the AEC in dependence on the different radiation qualities and the specific water volume. These characteristics can be compared with several screen-film systems (SFS), i.e., which dose K is required by the SFS in dependence on the X ray tube voltage (kV) to get the net density of Dn = 1.00. It is possible to check the way of operating of an AEC with sufficient accuracy but less time and energy are needed. The disparity of the characteristics of AEC and SFS and their results on radiological examination are discussed.