quantification of breast density using dualenergy mammography with liquid phantom calibration breast density is a widely recognized potential risk factor for breast cancer however accurate quantification of breast density is a challenging task in mammography the current use of plastic breastequivalent phantoms for calibration provides limited accuracy in dualenergy mammography due to the chemical composition of the phantom we implemented a breastequivalent liquid phantom for dualenergy calibration in order to improve the accuracy of breast density measurement to design these phantoms three liquid compounds were chosen water isopropyl alcohol and glycerol chemical compositions of glandular and adipose tissues obtained from nist database were used as reference materials dualenergy signal of the liquid phantom at different breast densities 0 to 100 and thicknesses 1 to 8 cm were simulated glandular and adipose tissue thicknesses were estimated from a higher order polynomial of the signals our results indicated that the linear attenuation coefficients of the breastequivalent liquid phantoms match those of the target material comparison between measured and known breast density data shows a linear correlation with a slope close to 1 and a nonzero intercept of 7 while plastic phantoms showed a slope of 06 and a nonzero intercept of 8 breast density results derived from the liquid calibration phantoms showed higher accuracy than those derived from the plastic phantoms for different breast thicknesses and various tube voltages we performed experimental phantom studies using liquid phantoms and then compared the computed breast density with those obtained using a bovine tissue model the experimental data and the known values were in good correlation with a slope close to 1 11 in conclusion our results indicate that liquid phantoms are a reliable alternative for calibration in dualenergy mammography and better reproduce the chemical properties of the target material