Digital Breast Tomosynthesis

Abstract

Digital breast tomosynthesis (DBT) is a technique developed to overcome these two shortcomings of mammography. The X-ray tube moves within a fixed arc (15–50° depending upon the vendor) obtaining multiple low-dose exposures. The data is reconstructed in the form of a stack of thin 1.0 mm slices in the direction of breast compression. This allows slicing of the dense tissues and enhancing an object at a specific depth while blurring out the objects at other levels. Several trials and studies have been published evaluating the role of DBT in breast cancer screening (Oslo Trial, STORM Trial, TOMMY trial, etc.). The performance of DBT has been better than 2D. The two most important benefits of DBT are increased cancer detection rate for invasive mammary carcinoma and reduced recall rate. Increased cancer detection is achieved because of the tomographic technique which makes the cancers more conspicuous (visible) in the surrounded blurred tissue. DBT is very good at detecting architectural distortion and spiculations, thereby picking up cancers that produce the above-described features. Addition of DBT to 2D doubles the radiation dose to the breast. Postprocessing algorithms are available, which use the reconstructed stack of image slices to create a synthetic 2D image. If DBT were to be performed on its own without 2D views, then the radiation dose would be comparable or even be lower than standard 2D views.