Digital Breast Tomosynthesis
Why Digital tomosynthesis?
In full-field digital mammography, normal overlapping breast tissue can often obscure cancer lesions thereby causing false negative diagnostics.
The use of flat-panel X-ray detectors (FPXDs) in mammography provides improved visualization, enabling improved diagnostics and increased patient throughput. But FPXD also opens possibilities of eliminating the effect of overlapping tissue by enabling the use of the 3D imaging.
One way to eliminate or reduce the effect of normal overlapping tissue is to create 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. Breast computed tomography (CT) exams can be used to obtain this 3D volume. Another, very convenient procedure that can be used is digital breast tomosynthesis (DBT). Because DBT can be performed on equipment similar to currently used digital mammography equipment, it can offer an easy extension of the current digital screening mammography.
How Does Digital Tomosynthesis Work?
Digital tomosynthesis 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 to detect cancer that may otherwise go undetected.
Two goals during a digital tomosynthesis exam are to limit the exam time and the radiation dose to the patient. The 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 at a relatively high speed, while maintaining good imaging performance at a low dose per image. Analogic has the technology to do this.
When will Digital Breast Tomosynthesis Be Available?
This new exciting technology is emerging as a significant improvement to current standard digital mammography. Most major OEMs are actively working to make it available to clinicians. DBT is coming soon, and Analogic’s expertise and high-performance detectors will help bring it to you.
To learn more about our direct X-ray detectors, click here.