Simple Optimisation Method in Mammography

The European Medical exposure directive encourages the establishment of diagnostic reference levels as a basis for optimisation. A dose reference level set at the third quartile of the dose distribution identifies the practices with unusually high doses. If image quality is quantified the 'worst quarter' principle can also be used to identify practices with less than optimal image quality. Performance of mammographic centres in Slovenia is evaluated annually. Evaluation includes mean glandular dose (MGD) calculation and image quality determination by means of imaging a simple mammographic phantom. Using the data from the period 1996-1999 distributions of MGD and each of the measured image quality parameters were obtained. Except for optical densities of films, reference levels are set to the border of the worst quarter of the distributions. Derived reference levels are then used to identify mammographic centres with higher MGD or lower image quality and to suggest how to improve their performance. (author)