[Quality assurance in roentgen diagnosis. Comparison of constancy test methods according to DIN and IEC and practical consequences in Germany].

Since 1987 constancy tests for X-ray imaging equipment are required by the German Röntgenordinance and are performed according to the DIN 6868 standards. On an international level, standards for these tests have been developed by the IEC (International Electrotechnical Commission, IEC 1223 series); however, these standards have so far not been applied in nation-wide quality programmes in any country. Typical aspects of both, DIN and IEC standards, are demonstrated for direct radiography and indirect radioscopy and indirect radiography as examples. DIN standards optimise test procedures for minimum effort and cost efficiency designed for execution even in small hospitals and practices by the users. For each type of x-ray equipment tests are performed with only one universal test device, which is precisely specified and independent of local conditions. Oplimisation is misation is missing for IEC test procedures; they are designed for more performance characteristics and need for each x-ray equipment more individual test devices, which are mostly open for local choice and need a considerably higher effort in respect of time consumption and test films compared to DIN. Adoption of the IEC standards for the constancy tests in Germany would involve considerable financial and organisational effort which is probably not counterbalanced by an increased benefit.