The Path Towards Low Dose CT: The Case of Breast CBCT

Commercial CT systems include tools to estimate the dose received by the patient in a CT scan, but they tend to overestimate the dose for large patients and underestimate it for small/pediatric ones. In this work we consider the case of Cone Beam CT (CBCT) for breast imaging to explore the feasibility of obtaining accurate and fast estimates of the dose received during a low dose CT. The Hybrid-Ultra MC algorithm, developed in the group for fast and accurate dose estimation, has been used for the study, with the well validated MC code PenEasy as the reference. Comparing analytical and realistic projections, we estimated the improvement achievable when the later ones are used in the reconstruction, and we concluded that when a realistic projection model is used and acquisition parameters are adapted to the density and size of the breast, CBCT images obtained under the dose limits of Digital Mammography (DM) may reach diagnostic quality.