Statewide midline depth dose intercomparison between dedicated film/screen and xerox mammography units

A statewide midline depth dose assessment of the mammography units in N.S.W. is presented and the results compared with similar overseas data. Film/screen units are shown to provide significantly less depth dose to the average patient when compared to the Xerox units in use in N.S.W. Twenty seven percent of the film/screen units were found to operate at a peak voltage below a level considered as adequate for proper image quality. A further twenty seven percent of Xerox units were found to operate at a peak voltage above that considered desirable for good contrast. In both cases this may lead to either needless exposure or missed microcalcifications and the need for modifications in either technique or equipment is considered essential