Technical feasibility proof for high-resolution low-dose photon-counting CT of the breast.

X-ray computed tomography (CT) has been proposed and evaluated multiple times as a potentially alternative method for breast imaging. All efforts shown so far have been criticized and partly disapproved because of their limited spatial resolution and higher patient dose when compared to mammography. Our concept for a dedicated breast CT (BCT) scanner therefore aimed at novel apparatus and detector design to provide high spatial resolution of about 100 µm and average glandular dose (AGD) levels of 5 mGy or below. Photon-counting technology was considered as a solution to reach these goals. The complete concept was previously evaluated and confirmed by simulations and basic experiments on laboratory setups. We here present measurements of dose, technical image quality parameters and surgical specimen results on such a scanner. For comparison purposes, the specimens were also imaged with digital mammography (DM) and breast tomosynthesis (BT) apparatus. Results show that photon-counting BCT (pcBCT) at 5 mGy AGD offers sufficiently high 3D spatial resolution for reliable detectability of calcifications and soft tissue delineation. KEY POINTS: • Photon-counting detector technology allows for spatial resolution better than 100 µm. • pcBCT allows for dose levels in the screening mammography range. • pcBCT provides the highest quality imaging of microcalcifications.

Performance of Photon-Counting Breast Computed Tomography, Digital Mammography, and Digital Breast Tomosynthesis in Evaluating Breast Specimens.

RATIONALE AND OBJECTIVES: This study compared a novel photon-counting breast computed tomography (pcBCT) system with digital mammography (DM) and digital breast tomosynthesis (DBT) systems. For this reason, surgical specimens were examined with all three techniques and rated by three observers. MATERIALS AND METHODS: A total of 30 surgical specimens were investigated with DM, DBT, and pcBCT; the associated images were shown to three experienced radiologists. Findings (22 microcalcifications and 23 mass lesions) were recorded and compared to the results of the pathological examination. Sensitivity and specificity for detection of microcalcifications and lesions were calculated and displayed using receiver operating characteristic curves. RESULTS: Sensitivity for microcalcifications was 82% for DM, 70% for DBT, and 85% for pcBCT. Specificity for microcalcifications was 71% for DM, 75% for DBT, and 83% for pcBCT. Sensitivity for lesions was 45% for DM, 62% for DBT, and 65% for pcBCT. Specificity for lesions was 76% for DM, 62% for DBT, and 76% for pcBCT. CONCLUSIONS: pcBCT showed a comparable or superior performance compared to the clinically approved DM and DBT systems. Mass lesion detectability can be increased further by the use of contrast media.