Evaluation of exposure factors of dual-energy contrast-enhanced mammography to optimize radiation dose with improved image quality

Background: Dual-energy contrast-enhanced mammography (DECEM) is an advanced breast imaging technique of digital mammography. Purpose: To assess the total radiation dose received from complete DECEM using different combinations of exposure parameters for low- and high-energy images. Materials and methods: A dedicated phantom with three different concentrations of iodine inserts was used. Each iodine insert was 10 mm in diameter and concentration of 1.0 mgI/cm(3), 2.0 mgI/cm(3), and 4.0 mgI/cm(3). The phantom was exposed at varying kVp levels. Mean glandular dose (MGD) was estimated. Contrast to noise ratio (CNR) and figure of merit (FOM) of the iodine inserts were used to assess the image quality. Results: The optimum CNR of the recombined images was obtained by using 28 kVp + 49 kVp tube voltage combination for 50 mm thickness, 50% fibroglandular phantom only with a 26% dose increase compared to the highest voltages (32 kVp + 49 kVp) that can be used for low energy (LE) and high energy (HE) imaging. The CNR value was increased with increasing iodine concentration (R-2 > 0.99). Conclusion: The use of as low as possible tube voltage for the LE imaging of standard 50% fibroglandular-50% adipose, 50 mm thickness breast while using the highest tube voltage for HE imaging has reduced the MGD while keeping optimum image quality.