a mightier mammogram.
by Margarite Nathe
Should you go digital or stick with film? If you’re buying a camera, you might ask which is easier, which takes better pictures, which is cheaper. If you’re talking about a mammogram, effective detection is the name of the game.
In October 2001, Carolina’s Etta Pisano, working with the American College of Radiology Imaging Network, began a four-year study by recruiting 49,528 healthy, cancer-free women for mammograms. Doctors at thirty-three sites all over the United States and Canada examined each woman using two different mammogram technologies: digital and film.
Film mammography, which has been the standard for over thirty-five years, transfers an image of the breast and its internal tissue onto a sheet of film. Digital mammography immediately creates the image as a digital computer file, which can then be enhanced, magnified, manipulated, and transferred to film if desired.
The researchers found that both technologies worked well for detecting cancers in the population of women tested. But physicians found more hard-to-spot lesions when they used digital technology to examine pre- and perimenopausal women, women under fifty, and women with dense breasts. Most women—about 60 percent—are in at least one of these subgroups. Most of the cancers the researchers found using digital mammography happened to be of the dangerous sort that must be detected and treated early.
Digital mammography offers faster imaging, easier storage—no worries about sheets and sheets of images—and easier transfer to other physicians. And most women are exposed to less radiation during digital mammograms than during film mammograms.
Two images of the same breast: film on the left, digital on the right. The cancer, indicated by the arrows, appears clearer in the digital mammogram. Image courtesy of Etta Pisano.
So why don’t we all insist on digital mammograms? The biggest obstacle is cost. Digital mammogram machines cost hospitals around $500,000. Machines for film mammograms usually cost around $75,000.
Researchers tested five digital mammography systems for the study: General Electric Medical Systems, Hologic, Fischer Imaging, Trex, and Fuji Medical Systems. Most of these are already approved by the Food and Drug Administration and are available for clinical use in the United States.
“These results will give clinicians better guidance and greater choice in deciding which women would benefit most from various forms of mammography,” Pisano says. “I think it’s important that those 60 percent get digital when it becomes available.” Given that an estimated 211,240 women in the United States will be diagnosed with breast cancer this year, more and better guidance may very well save lives.
Etta Pisano is a professor of radiology. She directs the creation of the School of Medicine’s Biomedical Research Imaging Center.