Sept. 4, 2008 -- Mammograms have long been the gold standard for detecting breast cancer, but they still miss as much as 15 percent of tiny tumors, usually located in dense breast tissue.
"We need a better way to detect cancer in the 25 percent of women over the age of 40 who have dense breasts," said Dr. Edward Coleman of Duke University Medical Center.
Molecular breast imaging, or MBI, is the latest experimental approach.
On a mammogram, a type of X-ray, too much healthy dense tissue lights up, limiting doctors' ability to see small tumors.
But with molecular breast imaging, women receive an injection of a short-acting, "radioactive tracer" that travels through the body and "latches on" to cancer cells. The revolutionary new cameras can then detect small tumors that mammograms often miss.
"Cancer cells absorb this tracer more intensely than normal breast cells," said Dr. Deborah Rhoades of the Mayo Clinic. "And that causes the tumor to light up."
Preliminary results from the Mayo Clinic found that among 940 women with dense breast tissue, molecular imaging found three times more breast cancers than mammography.
MBI is not a replacement for mammograms, but could serve as a complimentary form of detection for higher risk women.
Another added benefit of molecular imaging is that it tends to raise fewer "false alarms" than mammograms, meaning fewer women would have to go through unnecessary biopsies.
In addition, MBI is much less expensive than magnetic resonance imaging, or MRIs, the test now offered to many women with dense breast tissue.
The next step will be to study the two techniques against one another. The government is sponsoring a study to compare high-risk women.
Many of the country's leading cancer doctors have gathered at the American Society of Clinical Oncology conference in Washington, D.C., to learn about this new way of detecting breast cancer.
Researchers are now working on ways to reduce the amount of radiation used in MBIs. If researchers succeed, radioactive tracers could become a vital new tool for uncovering deadly tumors.