DIN EN 62494-1:2010-05

The direct connection between the dose at the detector and optical density (blackening) is well established in film-screen radiology. However, in digital radiography the connection between the detector dose and the greyscale values of the image which have been output by the system does no longer exist due to automatic image processing. Therefore, manufacturers of digital radiography systems have introduced so-called exposure indexes for their equipment. These are numbers which have been determined from the original image data of every image taken and which allow conclusions about the dose level at the image receptor. The standard contains a definition which has been specified independently from manufacturers; it contains requirements for the exposure index of digital X-ray systems for general applications. Image intensifier based systems and systems for mammographic and dental applications are not covered by this standard. The standard defines the exposure index only for images generated with a single irradiation event. Images generated from multiple irradiations, e.g. tomosynthesis, are not covered. This International Standard has been prepared by IEC/SC 62B "Diagnostische Bildgebende Geräte" ("Diagnostic imaging equipment") with the German collaboration of Joint Committee NA 080-00-16 GA "Bildgebende Systeme" ("Imaging systems") of NAR.