Soft copy brings out the best of digital mammography

Technology serves as springboard for advanced applications

By: Deborah R. Dakins

When breast imagers at the University of South Florida began using digital mammography for breast cancer screening in the late 1990s, it didn't take long for the team to appreciate the superior image quality of the technique, said Dr. Maria Kallergi, an associate professor of radiology. It turns out that was the easy part.

The hard part was mastering the multiple steps toward a full transition from film-based reading to soft copy. That involved not only becoming familiar with a new medium characterized by keyboard, monitors, and mouse, but also creating a way to fold the film-based priors into the soft-copy process and develop new workflow patterns for the technologists as well as radiologists.

"Digital mammography is a great concept, but it is only one of our six systems," she said. "We're not the only institution that faces the challenge of integrating digital images with film."

On the following pages, experts from California to Florida offer tips on achieving a smooth transition from film to soft-copy mammography. As Kallergi notes, once familiarity with new tools and techniques is attained, breast imagers never look back.

One of the reasons behind soft-copy mammography's strong user following is the ability, inherent in digital imaging, to capitalize on image enhancement and data interrogation features. It also enables more efficient use of computer-assisted diagnosis (CAD) and makes telemammography possible.

To date, four digital mammography systems have received approval from the FDA, and the technology has been in use for several years at both academic and community sites. Sales of full-field digital mammography systems totaled 400 in 2003, about 40% of mammography systems sold in the U.S. last year, according to industry estimates. System costs average $450,000.

Officially, the jury is still out on the clinical equivalency of full-field digital mammography to film. Initial results from the national Digital Mammographic Imaging Screening Trial (DMIST), which began in 2001 and completed its enrollment phase this spring, could emerge by early next year.

The study compares the accuracy of digital and film mammography for screening. And while the technical strengths of digital mammography are well known, DMIST will prove critical in documenting whether it improves detection and diagnosis of breast cancer.

Beyond digital mammography's potential contribution to screening, advanced work indicates that it could serve as a springboard for new imaging techniques. The increased quality and digital nature of data acquired facilitates new applications such as mammography tomosynthesis.

"If we could take a series of slices through the breast, getting rid of structural noise and overlapping breast tissue, we may find more cancers," said Dr. Etta Pisano, chief of breast imaging at the University of North Carolina, Chapel Hill, and DMIST chief investigator. "Tomography is one reason I'm bullish on digital mammography."