Role of Tomosynthesis in Detection and Characterization of Breast Masses

Abstract

Digital Breast Tomosynthesis (DBT) was developed in an effort to improve on the major success of mammography. DBT helped to overcome the over lapping of the normal structures of the breast which can obscure malignant tumors. In addition, the superimposition of structures in the breast can form a summation shadow, which appears to be a lesion when none is present. Both problems complicate the interpretation of conventional 2D mammograms )Kopans, 2014). In DBT, the x-ray tube is moved through a limited arc while the breast is compressed and a series of exposures are obtained. The range of this arc typically is (11-60°), the number of individual exposures typically ranges between (9-25) and exposures maybe continuous or pulsed (Sechopoulos, 2013). In DBT Selenium Detector is preferred, because of its high dose efficiency, with x-ray absorption of more than 95% at mammographic energies (Teertstra et al., 2010). Reconstructed images could be produced using a special mathematical algorithm, then may be viewed individually or sequentially in a dynamic cine mode at the workstation (Skaane et al., 2009). Advantages of DBT: DBT allows visualization (detection) and better characterization of non-calcified lesions in particular (Teertstra et al., 2010). DBT provides greater detail and clarity, and helps physicians to detect tumors that are easy to miss with the 2-D conventional approach (Skaane et al., 2009). Recall rates, Biopsy rates, Cancer detection rates, and Positive predictive values showed great improvement with the use of DBT (Destounis,2015). DBT Limitations: The large number of reconstructed images that lengthens interpretation time for radiologists (Vedantham et al., 2015). Special training of technologists is needed for positioning, which is slightly more difficult because of the larger detector size (Roth et al., 2014). Extremely large data files that require picture archiving system (PACS) storage (Conant, 2014). Future of Breast Tomosynthesis: The new digital mammography systems is a new step in getting the maximum benefit from DBT, which include: combining digital mammography with other imaging technology such as ultrasound, combining it with contrast enhancement techniques with its two main method either serial or dual energy and combining it with Computer-aided detection or diagnostic (CAD) systems (Helvie,2010). In conclusion Breast tomosynthesis provides a 3D imaging capability that allows the more accurate evaluation of lesions by enabling better differentiation between overlapping tissues. A lower recall rate, higher positive predictive value for a biopsy recommendation, and higher cancer detection rates are expected to result from the use of this technology. So it’s recommended to use DBT as a strong adjunct to 2D mammogram in both screening and diagnostic mammography.