Dual energy digital mammography has been used to suppress specific breast tissue, primarily for the purpose of iodine
contrast-enhanced imaging. Another application of dual energy digital mammography is to estimate breast density, as
defined by the fraction of glandular tissue, by suppressing adipose tissue. Adipose equivalent phantoms were used to
derive the weighting factor for dual energy subtraction at 2, 4, 6, and 8 cm thickness. For each thickness besides 8 cm,
measurements were taken over a range of densities (0, 50, and 100%) and used for calibration measurements to model a density map. Once the density map was verified with uniform slabs, the density map was evaluated with 50/50 CIRS 020 phantom at 2, 4, and 6 cm thickness and demonstrated the feasibility of using dual energy subtraction to estimate breast density on complex phantoms.