Why Digital Tomosynthesis?
In full-field digital mammography, normal overlapping breast tissue can often obscure cancer lesions, causing false-negative diagnostics in breast cancer screenings. Alternately, breast density also affects the cancer-detection rate, causing false positives and unnecessary stress for both women and radiologists interpreting scans.
The use of flat-panel X-ray detectors (FPXDs) in breast imaging provides improved visualization, enabling efficient diagnostics and increased patient throughput. But FPXD also opens possibilities of eliminating the effect of overlapping tissue by enabling the use of the 3D mammography in place of less efficient 2D mammogram imaging.
Unlike conventional mammography, our 3D imaging technique helps to reduce or eliminate the effect of normal overlapping tissue during a mammogram by creating a 3D reconstructed volumetric image of the breast. This image can be presented as slices, where only a small fraction of the tissue is visible and works even with a dense breast.
Breast computed tomography (CT) exams can be used to obtain this 3D volume, but another, very convenient procedure is digital breast tomosynthesis (DBT). Because DBT can be performed on equipment similar to currently used digital mammography equipment, it offers an easy extension of digital screening mammography. Better technique equals a clearer view, the right callbacks, and more targeted follow-ups.
How Does Digital Tomosynthesis Work?
A DBT test is similar to a CT scan. During a CT exam, images are obtained from a full 360º rotation of a detector/X-ray source around a patient. In digital tomosynthesis, the rotation of the detector/source is limited (e.g. 20º) as are the number of images that can be acquired. The 3-D reconstruction of this limited scan leads to very good in-plane resolution (e.g. 100 µm reconstructed pixel), but coarser Z-axis resolution (e.g. 1 mm thick slices). Still, this Z-axis resolution provides enough separation of normal overlapping tissue for breast cancer detection that may otherwise go unflagged.
Two goals during a digital tomosynthesis exam are to limit the exam time and radiation exposure to the patient during screening. The mammographic image acquisition time is approximately 15 to 20 seconds, and the radiation dose is only 1–1.5 times the radiation normally given in a standard screening exam. In order to perform tomosynthesis, the detector has to be able to acquire high-resolution images of the breast at a relatively high speed, while maintaining good imaging performance — even with dense breast tissue — at a low dose per image. Analogic has the technology to balance these goals.
When will Digital Breast Tomosynthesis Be Available?
Early detection of breast cancer is a critical component of health and medical care for women. A clinical health practice must improve accuracy while reducing exam times. A DBT screening mammogram tool is the answer radiologists and healthcare providers need for clinical performance.
This new exciting diagnostic tool is emerging as a significant improvement to current digital mammography. Most major OEMs are actively working to make it available to clinicians. Our new DBT is coming soon, and Analogic’s expertise and high-performance detectors will help bring it to your healthcare center.