[Physics, dosimetry, and quality control in mammography].

: The diagnostic value of mammography, especially in the early diagnosis of breast cancer, is closely related to examination optimization in terms of high-quality images with the lowest possible dose to the organ. Currently, "optimal" beams are produced by X-ray tubes with a Molybdenum anode, their voltage reaching 35 kV, using the K fluorescence line at 17.48 keV and absorption of photons with > 20 keV energy, through Mo filtration. The dose delivered with a mammographic examination is expressed differently in the literature reports on the subject: air exposure, skin exposure, dose at the midplane and mean dose; currently, it is recommended to specify the dose as "average glandular tissue dose", considering beam quality and the ratio between transmissions in perspex and tissues respectively. Threshold values for the average dose to the glandular tissue range 1.8 to 3 mGy with a grid and 0.9 to 1.5 mGy without the grid. The high quality standard of mammography requires quality assurance programs including the mammographic unit and the image acquisition and treatment systems. In Italy the "Dose and Quality in Mammography" program is in progress. According to the acceptance quality criteria established in the program and on the basis of the investigation of 272 centers, an acceptable dose-quality ratio was seen in 37.5% of the centers, low quality was found in 24.5%, high dose in 23.7% and high dose plus low quality in 14.1% of the whole of centers.