Digital Mammography and Tomosynthesis

One of the most recent advances in mammography, is digital mammography. In digital mammography, radiation transmitted through the breast is absorbed by an electronic detector, the response of which is faithful over a wide range of intensities. Once this information is recorded, it can be displayed by using computer image-processing techniques to allow arbitrary settings of image brightness and contrast, without the need for further exposure to the patient.

 With digital mammography, the magnification, orientation, brightness, and contrast of the mammogram image may also be altered after the exam is completed to help the radiologist more clearly see certain areas of the breast. The limitations of mammography are well known. Mainly, they include a low positive predictive value and a low sensitivity.These deficits stem largely from the superimposition of normal breast structures in the path of the X-ray beam.

 Digital mammographic systems have made breast tomosynthesis possible. Digital tomosynthesis, creates a 3-dimensional picture of the breast using x-rays. In Tomosynthesis, low-radiation-dose images were acquired as the x-ray source is moved in an arc above the stationary breast and digital detector. The resulting digital data set is reconstructed into tomographic sections through the breast in the orientation of acquisition—that is, craniocaudal, oblique, or 90° lateral.

 Tomosynthesis improves the specificity of mammography with improved lesion margin visibility and may improve early breast cancer detection, especially in women with radiographically dense breasts. Tomosynthesis may have great potential in screening and diagnostic breast imaging practices and other procedures, and initial results are certainly encouraging.