Error analysis of calibration materials on dual-energy mammography

Dual-energy mammography can suppress the contrast between adipose and glandular tissues and improve the detectability of microcalcifications (MCs). In clinical dual-energy mammography, imaging object is human breast, while in calibration measurements, only phantoms of breast-tissue-equivalent material can be used. The composition and density differences between calibration materials and human breast bring the differences of linear attenuation coefficient which lead to the calculation errors in dual-energy imaging. In this paper, the magnitude of MC thickness error from calibration materials has been analyzed using a first-order propagation of error analysis. This analysis shows that the thickness error from calibration materials ranges from dozens to thousands of microns which can not be ignored when carrying out dual-energy calculations. The evaluation of several popular phantoms shows that it is of great importance to adopt the phantom materials approaching human breast most.