by Brendon Nafziger
, DOTmed News Associate Editor | November 24, 2010
"Right now, we're looking at the forest and sometimes what we need to do, is look at the tree because that's where you have pathology," said Backenstoss.
"Certainly the intent of 3-D images is to reveal the inner architecture of the breast, which you can't always see satisfactorily on single plane images because you have so much superimposed fibroglandular tissue," she added.
The early promise of the technology has led to some speculation that the breast tomosynthesis device could generate $1 billion in sales, according to Reuters. Already, Hologic's shares have risen more than 4 percent since an FDA panel in September recommended clearing the device.
But despite the promise, serious questions remain.
Berg said some evidence suggests tomosynthesis could actually lag behind standard digital mammography in demonstrating cancerous calcifications, as radiologists will have to look through multiple slices together to perceive the lesions and the longer acquisition time for the 3-D images could result in motion blur.
"Again, we don't have a lot of published information on this, but there certainly seems to be a concern that we won't see malignant calcifications as well," she said. "We may be missing some of the early cancers if we were to switch to tomosynthesis alone."
While protocols for screening need to still be worked out, this could lead radiologists to take one tomosynthesis image and one standard 2-D mammogram, which "may actually make things more complicated," Berg said.
"We need more papers published," she said. "There's just very little published."
Workflow issues also remain to be worked out, as the images contain much more data than 2-D mammograms. Radiologists might have to spend more time reading exams.
"I'm told you can get relatively faster at it, but I can't imagine it's not going to take you longer than it takes now. But how much longer, I don't know," Berg said.
More data means the files are, relatively speaking, huge. Currently, mammograms average around 40 megabytes per image. But for tomosynthesis, it could be as high as 1 gigabyte per acquisition. And radiologists might want to take two sets of tomosyntheses of each breast. Vendors and providers will have to work out the best way to load up images before exams. Already, Berg said with the smaller-sized files patients can be forced to wait if there are problems calling up studies the night before.
But some factors might not be a problem. Despite early worries, Berg said that the published radiation doses only slightly surpassed the 0.4 mSv dose from a digital mammogram. "Now it's in the same ballpark," she said.