[Film-screen combinations for mammography].

Optimizing and standardizing mammography as well as its quality assurance are gaining in importance with regard to the screening programmes that are being initiated for the early detection of breast cancer. In Germany, the guidelines of the Bundesärztekammer, the directives implementing section 4 and section 16 of the Röntgenverordnung and the standards DIN 6868, Part 7 and 52 are available. The data in these standards concerning tolerances and guide values for physical variables of the imaging system are only partially consistent. This also applies to the comparison with the document "Quality criteria for x-ray exposures in medical diagnostics" of the Commission of the European Communities. The different statements concerning the switch-off value of the dose in particular, reflect an uncertainty as to how unsharpness and noise of the image receptor impair the medical value of the images. With regard to the increased demands for visual resolution capacity, it can be stated that the "Medical quality requirements" and the "Radiographic guide-lines" harmonize with one another only inadequately. Contrast is one of the most important image quality parameters in mammography. Practically no statement is made on this in the available documents. One reason for the present unsatisfactory situation is certainly the especially high demands placed on image quality in mammography. In the present paper, these points of criticism are discussed in detail and proposals for closer specification and better delineation of the physical image quality parameters are submitted.