"By optimizing the camera to detect smaller breast lesions, this technique should aid in the detection of early-stage breast cancer, something that was not possible with conventional gamma cameras," says Michael O'Connor, Ph.D., Mayo Clinic radiologist.

In the study, 40 women with suspicious findings on mammogram underwent molecular breast imaging: Twenty-six women had 36 malignant lesions confirmed at surgery. Molecular breast imaging detected 33 of the 36 lesions. In addition, four cancers were detected that were not seen on mammogram. Stephen Phillips, M.D., a Mayo Clinic radiologist involved in the study, said the technique yielded the highest sensitivity yet reported for a gamma camera in the detection of small breast tumors (less than 1 centimeter), reporting an 86 percent rate of detection (19 of 22 cancers).

One key feature that distinguishes this technique from mammography is that it relies on differences in the metabolic behavior of tumors vs. normal breast tissue. In contrast, mammography relies on differences in the anatomic appearance of tumors vs. normal tissue, differences that can often be subtle and obscured by densities in the surrounding breast tissue.

"Approximately 25 to 40 percent of women have dense breast tissue, which decreases the chance that a cancer will be visible on their mammograms," says Douglas Collins, M.D., a Mayo Clinic radiologist, who also worked on the study. "With molecular breast imaging, the visibility of the tumor is not influenced by the density of the surrounding tissue, so this technique is well-suited to find cancers in women whose mammograms may not be very accurate."

Deborah Rhodes, M.D., a Mayo Clinic physician and lead researcher in the study,
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11-Jan-2005