3D Breast Imaging Technology Results in Fewer False Positives
October 09, 2012
On the eve of undergoing a partial mastectomy of her right breast late in the winter of 2012, Linda Burroughs fielded yet another phone call from her radiologist at Dartmouth-Hitchcock Medical Center, Steven Poplack, MD.
"He'd been thinking about me and had re-examined the mammogram of my left breast, and he asked if I would be willing to join a study and have tomosynthesis - the very latest in breast-imaging technology," Burroughs recalls. "He told me, 'We have this new machine. It's 3-D.' I'd been having mammograms all my life, and I didn't know they were 2-D. But I said, 'Sign me up: I'm there."
As the 47th subject among 50 in the Dartmouth-Hitchcock portion of the clinical trial, Burroughs was signing up relatively late but just in time: Digital Breast Tomosynthesis (DBT) imaging, now offered at Dartmouth-Hitchcock, detected an abnormality on the left breast. An MRI biopsy confirmed the presence of more cancer, and Burroughs underwent partial mastectomies on both breasts.
Four days later, Burroughs was joining friends on a long-planned trip to Washington, D.C. Six months later, following precautionary radiation treatments, she is enjoying time with her husband at a family camp on Mascoma Lake in Enfield, N.H. - and a future that, for now, appears cancer-free.
"It's been an astonishing experience," Burroughs said. "This shows what it means to diagnose a person, to be able to learn so much more and be able to give you the right answers."
Poplack is quick to point out, after nearly a decade of research into the technology, that much study remains to be done on how many women tomosynthesis can and will help, and how it will help them. For example, while in Burroughs' case DBT detected an abnormality, it helped spare other subjects of the study the anxiety of receiving wrong first diagnoses.
"It's really a double benefit. It allows us to detect what we otherwise wouldn't see, and not go down the path of a false alarm."
"Things are no longer hidden," says Poplack, co-director of breast imaging at D-H. "On a mammogram, that tissue can look fairly complex, can kind of stack up to look like cancer and fool us into thinking there is a problem when there really isn't."
Poplack's team in radiology has been collaborating with researchers from the Norris Cotton Cancer Center and the Thayer School of Engineering since 1999 to compare tomosynthesis with other forms of breast-cancer detection.
To produce the 3-D images, a tube revolves around the breast in short arcs while sending out multiple x-rays in low doses. Radiologists then reconstruct the data gathered in a way that allows viewing of particular areas in thin layers of tissue.
While tomosynthesis exposes the patient to slightly more radiation than a conventional mammogram, the difference over time is "negligible," Poplack says - roughly equivalent to the amount to which one would be exposed on an airline flight from the east coast to Europe.
D-H was among the first institutions in the United States to do research on the technology, Poplack says, and one of five institutions that contributed data that ultimately led to approval from the federal Food and Drug Administration.
Nearing the end of phase II of the current clinical trial - under the financial support of the National Cancer Institute (NCI) - D-H researchers are analyzing data they gathered from Burroughs and the 49 other patients, comparing tomosynthesis with Contrast Enhanced Magnetic Resonance Imaging (CEMRI). Poplack expects to share what they've learned with his peers at the annual meeting of the Radiological Society of North America in late November.
"We hope to publish the results in full soon thereafter," Poplack says, adding that "we have our fingers crossed" for receiving additional NCI funding for continued research.
While the researchers continue to fine-tune the technology and strive to better understand its benefits, patients like Linda Burroughs are helping to spread the word in general about the promise of tomosynthesis for women with dense breast tissue, and in particular about the care that women can expect from clinicians and researchers at D-H.
"Another year [without detection of cancer in her left breast] could have been too late for me," says Burroughs, a former fundraiser for New Hampshire Public Television. "It's about the technology, but it's about the people, too. They are so driven."
Dartmouth-Hitchcock is a national leader in patient-centered health care and building a sustainable health system. Founded in 1893, the system includes New Hampshire's only Level 1 trauma center and its only air ambulance service, as well as the Norris Cotton Cancer Center, one of only 40 National Cancer Institute-designated Comprehensive Cancer Centers in the nation, and the Children's Hospital at Dartmouth-Hitchcock, the state's only Children's Hospital Association-approved, comprehensive, full-service children's hospital. As an academic medical center, Dartmouth-Hitchcock provides access to nearly 1,000 primary care doctors and specialists in almost every area of medicine, as well as world-class research at the Audrey and Theodor Geisel School of Medicine at Dartmouth.