Mammography is a verywell-established imaging modality for the early detection and diagnosis ofbreast cancer. However, since the introduction of digital imaging to the realmof radiology, more advanced, and especially tomographic imaging methods havebeen made possible. One of these methods, Digital Breast Tomosynthesis (DBT),has finally been introduced to the clinic for routine everyday use, withpotential to in the future replace mammography for screening for breast cancer.In conventional geometric tomography, the x-ray tube and image receptor move insynchrony on opposite sides of the patient to produce a plane of structures insharp focus at the plane containing the fulcrum of the motion; all otherstructures above and below the fulcrum plane are blurred and thus less visiblein the resulting image. Tomosynthesis improves upon conventional geometrictomography in that it allows an arbitrary number of in-focus planes to be generatedretrospectively from a sequence of projection radiographs that are acquiredduring a single motion of the x-ray tube. By shifting and adding theseprojection radiographs, specific planes may be reconstructed.
The extensiveresearch performed during the development of DBT. This study involving thereview of the DBT image acquisition process and post-acquisition technique aswell. Moreover, various DBT system parts are reviewed. It is include systemdesign, the geometry and technique optimization, and the post-acquisitionaspects. Besides, the reconstruction methods, image analysing and processing,and the advanced applications being investigated for breast tomosynthesis.
1.IntroductionStandard mammography is a low cost, fast, non-invasive x-ray studythat involves relatively low doses of ionizing radiation. However, thetwo-dimensional (2D) nature of mammography results in tissue superposition,which can create two problems: dense glandular tissue located above and/orbelow a lesion of interest can reduce the visibility of the lesion (reducingsensitivity), or two or more normal features that are only vertically separatedcan appear to be the projection of a lesion of interest (reducing specificity).These two phenomena are partially responsible for a sensitivity and specificityof screening mammography of 83.5% and 90.9%, respectively 1I.
These values may be lower for women with densebreasts 2, 3I.Theintroduction of digital acquisition has assisted improve mammography byavoiding screen-film’s narrow range of linear response, among other issues.However, conventional mammography still only acquires a two-dimensional (2D)projection of a three-dimensional (3D) object, maintaining the issue of tissuesuperposition. Potentially, the most important contribution of digitalmammography is its flexibility, which allows for the development of imagingmethods that can resolve some of the limitations of mammography. Specifically,to overcome the loss of information in the third dimension, among other advantages,two new imaging methods have been developed: dedicated breast tomosynthesis andcomputed tomography imaging of the breast 4–10I.
While dedicated breast computed tomography CT remains promising, Digital breasttomosynthesis is now clinical technology, with different systems being approvedone system in the U.S. over the last few years and having received approval forclinical use around the world (see Table I). Tomosynthesis is a technology thatenables pseudo tomographic imaging by acquiring a limited number of X-ray projectionsfrom a narrow angular range, and combining these projections to reconstruct a pseudo-3Dimage. An in-depth discussion of the history of the development oftomosynthesis has been published by Dobbins and Godfrey 11I and Dobbins 12I. Intomosynthesis imaging of the breast, first demonstrated by