[The omitted x-ray examination--benefit and risk--a comparison].

Today the risk of omission of an x-ray examination is often underestimated compared with the assumed stochastic - i.e. random - risk of radiation exposure associated with the x-ray examination. The benefit of the x-ray examination can be estimated by considering how it influences the diagnostic decision and the therapy. Three degrees of justification (indication) supply proof of different degrees of the proportion of benefit gained. It is evident that some of the x-ray examinations that are being performed, are unnecessary, whereas on the other hand even so-called routine x-ray examinations can yield a therapeutically relevant finding in some patients. A comparison of benefit and risk shows that the estimated benefit exceeds the assumed irradiation risk by several orders of magnitude. This is exemplified by examinations of the thorax and lumbar vertebral column. The guidelines issued by the German Federal Chamber of Physicians on quality assurance in x-ray diagnostics and CT result in a considerable reduction of patient doses. Advantage must be taken of the benefit of x-ray examinations performed with an extremely critical eye on the relevant indication and with minimised irradiation exposure. Omitting an indicated examination may endanger the patient to such an extent that major neglect of the irradiation risk is warranted.