BI-RADS guidelines recommend an assessment of breast composition to be included in the analysis of the mammogram [8].
At baseline, we observed statistically significant differences in the breast composition and indicators of metabolism for premenopausal and postmenopausal groups, confirming previous studies [ 47].
Whereas some studies have suggested that density adds little to risk prediction [ 40], some find AUCs for density or another breast composition measure alone of 0.6 to 0.8 [ 41- 44], which is similar to those observed for the Gail and other models.
The scans were calibrated to a 2-compartment model of fat (stearic acid) and fibroglandular tissue using custom phantoms of a known range of breast composition and thickness [ 14, 19].
Following the Dance approach, AGD can be calculated by the equation [9]: AG D={k_{a,i}cdot gcdot ccdot s (1)where g is the conversion factor from k a,i to AGD for a standard breast of 50% glandularity; c takes into account the differences of breast composition from the standard 50% glandularity (varying in the range 0.885–1.306), and s depends on the x-ray spectrum used.
It represents a cost-effective, empowering, noninvasive technique to increase awareness of breast composition in these high-risk women.
Second, breast composition is a function of breast thickness in the dose model, and will thus incorrectly vary for RP and FP.
Mammograms reveal the characteristics of breast composition, because stroma and epithelium attenuate X-rays more than does fat and so appear light, whereas fat appears dark [ 1].
The first generation calibration phantom (Gamma) used for this method has provided preliminary data on 8,600 women to show that %FGV is reproducible to approximately 2 % between successive measures and accurate to known standards of breast composition using reference phantoms [ 17].
Since breast composition is an inherent property of the breast, we chose to use the breast composition based on RP for dose calculation for both RP and FP.
