Experimental results of the first prototype direct-indirect dual-layer flat-panel detector for contrast-enhanced digital mammography and contrast-enhanced digital breast tomosynthesis

Contrast enhanced digital mammography (CEDM) and contrast enhanced digital breast tomosynthesis (CEDBT) highlight the uptake of iodinated contrast agent in breast lesions in dual-energy (DE) subtracted images. In conventional methods, low-energy (LE) and high-energy (HE) images are acquired with two separate exposures, referred to as the dual-shot (DS) method. Patient motion between two exposures could result in residual breast tissue structure in DE images, which reduces iodinated lesion conspicuity. We propose to use a direct-indirect dual-layer flat-panel detector (DI-DLFPD) to acquire LE and HE images simultaneously, thereby eliminating the motion artifact. The DI-DLPFD system comprise a k-edge filter at the tube output, an amorphous-selenium (a-Se) direct detector as the front layer, and a cesium iodide (CsI) indirect detector as the back layer. This study presents the CEDM and CEDBT results from the first prototype DI-DLFPD. For comparison, CEDM and CEDBT images were also acquired with DS technique, with simulated 2mm patient motion between LE and HE exposures. The figure of merit (FOM) used to assess iodinated object detectability is the dose normalized signal difference to noise ratio squared. Our results showed that DI-DLFPD images exhibit complete cancellation of breast tissue structure, which led to significant improvement in iodinated object detectability and more accurate iodine quantification, compared to DS images with simulated patient motion.