Table 2 Comparison between k _a,i (mGy) measured (k _{a,i meas} ) and calculated by Equation 4 (k _{a,i calc} ) for different mammography units. Y _tb (mGy · mAs^–1) is the yield of the mammographic device (calculated at 28 kVp, different for each anode-filter combination) and d (cm) is the breast thickness simulated by different solid-water phantoms. FID is the focus-image distance (cm) for the device considered

From: Average absorbed breast dose in mammography: a new possible dose index matching the requirements of the European Directive 2013/59/EURATOM