A study of quality assurance in mammography

Full text. Nowadays mammography has two definitive important roles: as a complementary tool to confirm clinical findings and for the detection of early breast cancer. To reach and maintain the standards of image quality within the frontiers of reasonable radiation doses, the facilities must follow a QA program. The objective of this study is to accomplish such a program in three school hospitals in Rio de Janeiro. We made assessment of clinical images using the Accreditation American Phantom and measured the patients skin entrance doses with TLD 100. In each facility we evaluated the technical parameters of the mammographic units using a Victoreen 4000 M+ and an evaluation of the compression devices. The 3 hospitals studied use film and screen Min R Kodak and have Kodak processors, none of them dedicated to mammograms. The tube voltage, measured was not significantly different from the indicated values, the variations were lesser than 5%. In one of the hospitals the kVp did not show reproducibility, the coefficient of variation was too high - 1,02. The same facility showed an exposure time with variation of 7% and we asked for corrective action. Measures of HVL showed the same value for the 3 hospitals the compression were adequate. The patients skin entrance doses were measured with TLD 100 and showed the range 3,25 a 10,26 mGy. This range is due to differences in density and thickness of the breast. The doses values were in accordance with the Quality Criteria for Mammography of the Commission of the European Communities