[Progress in mammography technics. Bimetal anode tubes and selective filtration technic]

The use of molybdenum (Mo) as material for anodes and filters in mammography has been a result of contrast optimisation for breasts of low to medium radiation absorption. To penetrate denser breasts the kV must be increased, thus increasing the fraction of the harder radiation component and deteriorating image contrast. Besides this an increased radiation exposure to the patient must be accepted. In these cases the flexible use of rhodium (Rh) as anode and filter material is promising. A newly developed mammographic equipment (Senographe DMR, General Electric-CGR) offers these features. With selective rhodium filtering and anode material our measurements confirm a reduced radiation exposure (less than 50%) in dense breasts with significantly improved image contrast compared with the conventional molybdenum technique.