Through collaboration and innovation, Mayo Clinic professionals have developed a new method of detecting breast cancers that provides similar information as high-cost MRIs with the low-dose radiation of mammograms. In a recent study, when high-risk women with dense breasts were screened for the first time using this promising new technique, called Molecular Breast Imaging (MBI), it detected three times as many cancers in the group as mammography.
Deborah Rhodes, M.D., a preventive medicine specialist at Mayo, was frustrated with existing imaging options. Mammography, which uses low-energy X-rays, is the current standard for annual screenings. Because both breast tumors and dense breast tissue appear white on a mammogram, mammography is significantly less effective in detecting tumors, especially in women whose breasts are considered dense. "For every cancer you were finding, you were missing one. Some women were coming in for mammograms and going away with a false sense of reassurance," says Dr. Rhodes.
She teamed with medical physicist, Michael O'Connor, Ph.D., who was developing a new type of gamma camera at Mayo Clinic. "Gamma radiation has the distinct advantage of being unaffected by the density of the breast tissue," says Dr. O'Connor. "Imaging the breast with gamma detectors allows you to detect tumors that would be obscured on mammogram by the background density."
Working with Carrie Hruska, Ph.D., a biomedical engineer, and a team of Mayo Clinic radiologists, the MBI team has focused on reducing the radiation dose associated with MBI so that it will be comparable to mammography. The preliminary results of an ongoing study comparing screening mammography with low-dose MBI are striking.
Amy Conners, M.D., one of the Mayo radiologists working on MBI, noted that of the eight breast cancers detected thus far in the study, MBI found seven and mammography found none. Says Dr. Conners, "We are very excited about MBI. It offers the potential of a low-cost and low-risk option for patients whose cancers may be invisible on the mammogram."
From a patient's perspective, MBI is similar to a mammogram but with two-thirds less compression of the breast. Also with MBI, a radioisotope (a tracer which breast-tumor cells preferentially absorb) is injected into the patient's arm. Two 10-minute images are taken of each breast, and tumors show up as bright spots on the MBI films.
MBI, which is now approved by the Food and Drug Administration and available at Mayo Clinic in Minnesota, may not replace mammography, but it will help improve the early detection of breast cancer.
MBI shows great promise for turning more breast cancer patients into survivors — sooner.
Hear Dr. Rhodes' impassioned TED talk about a new tool for tumor detection that's three times as effective as traditional mammograms for women with dense breast tissue.