Dosimetric methods for and influence of exposure parameters on the establishment of reference doses in mammography

For the establishment of reference doses in mammography it is important to apply a dosimetric model relevant for risk assessment. Differences in dosimetric methods applied in mammography are related to the dosemeters used, e.g. thermoluminescent detectors and ionisation chambers, and the dosimetric quantities determined. i.e. entrance surface air kerma, entrance surface dose or average glandular dose. The exposure parameters influencing absorbed dose due to mammography include the X ray tube assembly, i.e. anode material, filtration and tube voltage; the exposure conditions, e.g. antiscatter grid, automatic exposure control and magnification; and characteristics of the film-screen combination including film processing and film density. The female breasts examined can be represented, on average, by a phantom or by a representative sample of patients. Reference values established in various protocols for entrance surface air kerma, entrance surface dose and average glandular dose are presented and discussed.