Digital Breast Tomosynthesis with Minimal Breast Compression David A. Scaduto * , Min Yang, Jennifer Ripton-Snyder, Paul R. Fisher, Wei Zhao Department of Radiology, Stony Brook University, L4-120 Health Sciences Center, Stony Brook, New York 11794-8460 ABSTRACT Breast compression is utilized in mammography to improve image quality and reduce radiation dose. Lesion conspicuity is improved by reducing scatter effects on contrast and by reducing the superposition of tissue structures. However, patient discomfort due to breast compression has been cited as a potential cause of noncompliance with recommended screening practices. Further, compression may also occlude blood flow in the breast, complicating imaging with intravenous contrast agents and preventing accurate quantification of contrast enhancement and kinetics. Previous studies have investigated reducing breast compression in planar mammography and digital breast tomosynthesis (DBT), though this typically comes at the expense of degradation in image quality or increase in mean glandular dose (MGD). We propose to optimize the image acquisition technique for reduced compression in DBT without compromising image quality or increasing MGD. A zero-frequency signal-difference-to-noise ratio model is employed to investigate the relationship between tube potential, SDNR and MGD. Phantom and patient images are acquired on a prototype DBT system using the optimized imaging parameters and are assessed for image quality and lesion conspicuity. A preliminary assessment of patient motion during DBT with minimal compression is presented. Keywords: digital breast tomosynthesis, breast imaging, breast compression, scatter, image quality, x-ray imaging, mean glandular dose 1. INTRODUCTION Mammography employs compression of the breast to both improve image quality and reduce radiation dose. Contrast resolution is improved through breast compression by both decreasing the scatter-to-primary ratio, and utilizing lower x- ray energy for better soft tissue contrast. Lesion conspicuity is increased by redistributing breast tissue and reducing the superposition of structures. Additionally, compression immobilizes the breast, reducing motion artifacts during acquisition. Finally, the decrease in breast thickness results in lower mean glandular dose (MGD). However, patients often report discomfort associated with this compression, and this discomfort has been cited as a potential cause for noncompliance with recommended screening practices. 1,2 Additionally, breast compression has been shown to occlude blood flow in the breast 3,4 , a potential complication when imaging with intravenous contrast agents, especially when contrast kinetics and enhancement quantification are investigated. Restricted blood flow due to breast compression has been cited as a potential cause of the inability to consistently correlate contrast kinetic curves with histopathology in some contrast-enhanced digital mammography studies 5–7 , as has been achieved in compression-free contrast-imaging modalities like breast MRI. 8,9 Reducing the compression used in x-ray imaging of the breast is thus desirable to both increase patient compliance and potentially improve cancer diagnosis in contrast-enhanced imaging. Previous studies investigating the effect of breast thickness in planar mammography have shown that the consequent increased breast thickness results in a loss of spatial 10 and contrast resolution 11 due to geometrical unsharpness and increased scatter radiation, respectively, confirming that reducing breast compression will lead to degradation in image quality. Digital breast tomosynthesis (DBT) is a three-dimensional (3D) imaging technique wherein projection images acquired around the breast are reconstructed into a quasi-3D image volume. Due to the improved tissue separation afforded in the depth direction, DBT may not suffer the same degradation in lesion conspicuity as full-field digital mammography (FFDM) when breast compression is reduced. However, due to the oblique angles at which projections are acquired, anti-scatter * david.scaduto@stonybrookmedicine.edu; phone +1-631-444-2004 Medical Imaging 2015: Physics of Medical Imaging, edited by Christoph Hoeschen, Despina Kontos, Proc. of SPIE Vol. 9412, 94121Y · © 2015 SPIE · CCC code: 1605-7422/15/$18 · doi: 10.1117/12.2081543 Proc. of SPIE Vol. 9412 94121Y-1