In an apparatus and associated method, by analyzing video images of compression of a breast of a patient in a compression unit, an actual contact-area of the tissue of the breast of the patient, which tissue is pushed onto a gauze of a compression element of the compression unit, is increased by changing a volume. As such, a pressure is increased, in at least one sub-chamber of a positioning unit integrated in the compression unit, such that the actual contact-area matches a first area, which is the maximum possible based on an outer contour of the breast.
