Absorbed breast dose: dependence on radiographic modality and technique, and breast thickness

The increased use of mammography has brought into focus the necessity for radiation dose reduction. In particular, the effect of radiographic technique on radiation dosimetry is not well documented. In this paper, the dependence of absorbed dose on radiographic modality, radiographic technique, and breast thickness is studied, with the following principal results: Breast thickness and incident half-value layer (HVL) are sufficient to characterize the normalized (mrad/incident roentgen) breast dose. The average breast dose depends on both beam HVL and kVp; the dependence on breast thickness is more pronounced for screen-film mammography, indicating the need for firm compression. Screen-film mammography shows substantial dose savings over xeromammography for thinner breasts imaged without a grid; this dose advantage disappears for thicker breasts and is generally reversed when a grid is used.