Experience in retake analysis for digital mammography at a university hospital.

Data from one digital mammograph (flat detector active area of 19.2 x 23 cm(2)) were collected over a 1-year period using locally developed software in order to evaluate retakes, their rates, their causes and the possible measures to reduce their occurrence. Among them, 7.1 % of the images were marked as repetitions, and in 16 % of the studies, at least one image was repeated. When evaluating causes of retakes, the primary cause was incorrect positioning (49 %), closely followed by additional retakes in cases of large breasts (44 %). When dealing with large breasts and using a small flat panel, additional images were necessary to fully visualise the breast, and as a consequence, some breast regions received repeated radiation exposure. Moreover, a small detector increases retakes in breasts slightly wrongly positioned. To try and reduce the retake rate, it is important to plan training sessions based on images selected from the retake analysis.