Development of acceptability criteria in mammography

Quality assurance protocols and standards of performance for X-ray mammography equipment are probably the most developed of any in the area of diagnostic radiology, due to the exacting demands on image quality required in population-based breast cancer screening programmes. Both qualitative and quantitative acceptability criteria have been published for X-ray mammography by considering the image quality needed clinically in screening programmes. Consequently, the task of developing a consensus for acceptability criteria appears to be relatively easy at first glance. However, there are two contentious issues that must be considered; the first is whether standards based on breast cancer screening can be transposed to equipment used for women referred for imaging with breast symptoms. The second relates to the use of image-quality assessment based upon the observation of details in test phantoms. In respect of the former, there was general agreement that only one set of acceptability criteria should apply to mammographic X-ray equipment. With regard to image-quality assessment, the weakness of the observer-based methods was recognised and a consensus position developed. This paper describes the development of a consensus on acceptability criteria and proposes both qualitative and quantitative criteria for use on all mammographic equipment. Some test approaches and criteria for image displays, in particular, were omitted from the document as concerns about their robustness emerged during the consultation phases of the revision. Clearly, further scientific work is needed in these areas.