Influence of anode-filter combinations on image quality and radiation dose in 965 women undergoing mammography.

Abstract

To evaluate how anode-filter combinations influence image quality in and mean glandular dose to breasts of different thicknesses and compositions. Mammograms were obtained with a molybdenum (Mo) anode and a Mo filter at 26 kVp, a Mo anode and a rhodium (Rh) filter at 27 kVp, or a tungsten (W) anode and a Rh filter at 26 kVp in 965 women. One anode-filter-tube voltage combination was used in the right breast and another in the left. The mean glandular dose to each breast was calculated. Image contrast was highest in the Mo-Mo mammograms. However, depiction of the glandular tissue, pectoral muscle, and skin and subcutis was significantly (P < .001) better with the Mo-Rh and the W-Rh than with the Mo-Mo combination. The average mean absorbed doses to the glandular tissue for W-Rh and Mo-Rh were 50% and 75%, respectively, of that for Mo-Mo. Breast thickness is the most important parameter in selection of an anode-filter-tube voltage combination. Compared with Mo-Mo, both Mo-Rh and W-Rh gave good image quality of the mammary gland and a considerably lower absorbed dose. Mo-Rh-27 kVp is recommended for breast thicknesses of 60 mm or less; W-Rh-26 kVp, for breast thicknesses of greater than 60 mm.