Low-dose mammo screening: Better images, fewer callbacks?
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| Sectra MicroDose L30 full-field digital mammography incorporates photon-counting technology. |
The cornerstone of the system is photon-counting technology, which individually detects x-ray photons and halves the radiation dose while boosting image quality. The combination packs a powerful punch and addresses the two primary issues in mammography screening—accuracy and dose—said Etta D.Pisano, MD, professor of radiology and vice president for medical affairs at Medical University of South Carolina (MUSC) in Charleston.
Pisano conducted Sectra’s 510(k) trial that compared the accuracy of the MicroDose system to another digital mammography system. In a substudy of the trial, readers compared lesion visibility of two systems.
“Sectra performed as well or better than the other system in every single part of the study,” Pisano shared. “I’m confident in its image quality for screening or diagnostic studies.”
FDA approval in the U.S. came on the heels of Health Canada’s approval of the system earlier this year.
Ontario Diagnostic Centres, Radiology Associates in Toronto and Mississauga, Canada, completed an extensive survey of the digital mammography marketplace last fall and ultimately invested in four Sectra systems.
The first system has been running for a few weeks, and early feedback is quite promising. “We had three patients with digital priors from outside institutions,” reported Murray Miller, MD, managing director, Ontario Diagnostic Centres. “One study had a dose eight times as high as the Sectra system. And the visualization on the Sectra system is spectacular. When you look at these images side-by-side with images from other digital vendors, it looks like there’s motion on the other images.”
In fact, Sectra’s system exposes women to an average of 50 percent less dose than other digital systems and 80 percent less dose than analog mammography systems. “The dose is lower, so women can have two mammograms at the same dose of a single exam,” confirmed Pisano.
“Whether dose reduction concerns are clinically significant or not, we want to err in the safe side. And even with these low doses, we are seeing much more detail, including subcutaneous tissue and nipple detail, than with other systems,” Miller said.
However, the lower dose exposure during screening represents just one part of a three-part story that extends to reduced callbacks and increased accuracy.
Miller anticipates following in the footsteps of another digital pioneer, BreastCheck, the Irish Breast Screening Program, which provides a multi-vendor screening program. At the annual meeting of the European Congress of Radiology in March, Irish researchers reported that Sectra MicroDose mammography had the highest cancer detection rate of the various vendors’ systems at about 60 percent of the radiation dose.
“My guess is that we’ll see the same results. The combination of the details we can see and a reduced recall rate will add up to improved detection,” predicted Miller.
“The bottom line,” concluded Miller, “is that this is a revolutionary technology. Doses coming from other systems range from 1.2 to 2.2 mGy. Sectra averages 0.35 to 0.6 mGy. At that point, the concerns about radiation exposure becomes much less.”