Evaluation of dose and quality in mammography. First results of DQM programme

A programme for mammography optimisation in 31 units is carried out. The main parameters affecting dose and image quality (HVL, focal spot and exposure) are measured by means of practical devices: dosemeter, star pattern and phantoms. The dose and image-quality evaluations show that routine mammography is frequently not optimised. In fact exposure HVL, resolution and optical density values show a wide interval range; in particular, even units using the same type of X-ray apparatus and film-screen combination present very different exposure values. The authors' exposure and dose values are compared with those of 27 screening centres of the Joint ACS/NCI Breast Cancer Detection Demonstration Project, where mammography is supposed to be optimised. The lowest exposures are about the same but the maximum exposures are very different. The difference was expected; in fact, the authors' exposure data are comparable to the first results of BENT (USA), where all the mammographic units were considered, not only the screening ones. Units that are now working in optimal conditions may start a quality assurance programme to maintain these conditions; units not optimised may seek better conditions with help from the programme. (author)