A device that can only fulfil its purpose when used together with and enhance the function of a diagnostic mammographic x-ray system. It is used to take two pictures of a breast from two different angles. On the basis of this stereoscopic picture set, it is possible to determine the exact position of a lesion in the breast and a cytological sample of this will be taken. This device or technique may be built-in to some diagnostic x-ray systems for mammography.