Molecular Imaging News
January 12, 2005
Mayo Clinic Researchers Report Success in New Molecular Breast Imaging Technique
Using a gamma camera specially designed for breast imaging, Mayo Clinic researchers reported success in identifying small malignant breast lesions even in dense breast tissue.
“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,” said Michael O’Connor, PhD, Mayo Clinic radiologist.
In the study reported in the January issue of Mayo Clinic Proceedings, 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, MD, 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,” said Douglas Collins, MD, 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, MD, a Mayo Clinic physician and lead researcher in the study, said, “We have long recognized that screening for breast cancer with mammograms may not be sufficient in some groups of women, particularly women at increased risk for breast cancer, many of whom also have dense breast tissue. We need a technique that can reliably find small breast tumors but is not impaired by dense breast tissue. Our early results suggest an important role for molecular breast imaging in filling this critical gap.”
In an editorial in the same issue of Mayo Clinic Proceedings, Rachel Brem, MD, SNM member and director of breast imaging and intervention at George Washington University Medical Center in Washington, DC, said the Mayo Clinic study furthers knowledge and gives additional credibility to molecular breast imaging. Dr. Brem noted that additional studies are needed at multiple medical centers to help refine and advance the findings.
In the editorial, Dr. Brem commended the Mayo researchers and said, “I hope that with time, molecular breast imaging, using a high-resolution breast-specific gamma camera will be embraced and used by breast imagers and nuclear medicine physicians for the benefit of women, for the improved diagnosis of breast cancer, and ultimately for better survival from breast cancer.”