[en] At the beginning informations are given of serial radiological examinations, of lung investigations of all medical employees, and of blood donors. Very low radiations doses are claimed for all provisional care investigations. This is guaranteed by the new large format image intensifier (Siemens Optilux 57). The important technical data of this large format image intensifier are given, which lead to reduction of radiation dose and film expenses. Experiences with the new large format image intensifier of more than 1500 ivestigations of blood donors and medical employees are described. (orig.)