- How Does Digital Mammography Differ From Standard Mammography?
- Promising Developments in Digital Mammography
As stated earlier, preliminary results of the Digital Mammographic Screening Trial (DMIST), released in September 2005, show that digital mammography may be more accurate at detecting breast cancer in some women than standard film mammography. According to the study results, digital and standard film mammography had similar accuracy rates for many women. However, digital mammography was significantly better at screening women in any of the following categories:
- under age 50, regardless of what level of breast tissue density they had
- of any age with very dense or extremely dense breasts
- pre- or perimenopausal women of any age (defined as women who had a last menstrual period within 12 months of their mammograms)
The FDA approved the first "full-field" digital mammography scanner to screen for and diagnose breast cancer in February 2000. Before applying for FDA certification, data was gathered from 662 patients at four institutions: the University of Colorado, the University of Massachusetts Medical Center, Massachusetts General Hospital, and the Hospital of the University of Pennsylvania. The data compared hard copies of digital breast images on film to conventional mammography films finding that digital mammography is as effective at detecting breast cancer as standard film mammograms. A separate study revealed that the digital mammography scanner showed a slight advantage in the visibility of breast tissue at the skin line.
While digital mammography is quite promising, it still has additional hurdles to undergo before it replaces conventional mammography. Digital mammography must:
- provide higher detail resolution (as standard mammography does)
- become less expensive (digital mammography is currently several times more costly than conventional mammography)
- provide a method to efficiently compare digital mammogram images with existing mammography films on computer monitors
Standard mammography using film cassettes has the benefit of providing very high detail resolution (image sharpness), which is especially useful for imaging microcalcifications (tiny calcium deposits) and very small abnormalities that may indicate early breast cancer. While full-field digital mammography may lack the spatial resolution of film, clinical trials have shown digital mammography to be at least equivalent to standard film screening mammography. This is because digital mammography has the benefit of providing improved contrast resolution, which may make abnormalities easier to see. Various manufacturers are trying to develop digital mammography systems with detail resolution equivalent to standard film mammography while also providing the benefits of digital mammography noted above.
The high cost of digital mammography is a major obstacle. Digital mammography systems costs roughly 1.5 to 4 times as much as standard mammography equipment. Standard mammography systems are currently installed in over 10,000 locations across the United States. It may take years for this current equipment to be updated or replaced and for digital mammography to become widespread.
- The September 23, Imaginis report, "Study: Digital Mammography Better Than Standard Mammography at Detecting Breast Cancer in Some Women," is available at http://www.imaginis.com/breasthealth/news/news12.01.00.asp
- To learn more about the full-field digital mammography and other advances in breast imaging, please visit http://www.imaginis.com/breasthealth/news/news12.01.00.asp.
Updated: May 4, 2008