Digital Tomosynthesis: Another Possible Mammogram Replacement for Breast Cancer Diagnosis?
The Big Squeeze. Cartoons have been drawn about it, jokes made about it, pain-preventive measures sympathetically prescribed… But there’s really no solution for the pain some women experience during a mammogram. Yes, the MammoPad® breast cushion has definitely made mammograms a warmer, somewhat friendlier experience than they’ve been in the past (and if your mammogram provider doesn’t yet use MammoPads, ask why not!) Still, a significant number of women over 40 put off, “forget,” or fail to schedule their annual mammogram because it’s an unpleasant experience–worrisome emotionally, and physically painful.
What Might Replace the Mammogram? What's Digital Tomosynthesis?
According to a seminar I recently attended at Norris Cotton Cancer Center here in New Hampshire, there’s a new technology waiting in the wings to replace mammography. Petra Lewis, a diagnostic radiologist specializing in breast cancer at NCCC, noted at the seminar that “Within 10 years, every woman who comes here will be having this” in place of a mammogram. And what, exactly, was she talking about? Digital tomosynthesis. Mark these words: you read it here first.
With a mammogram, radiologists get two views of your breast: from the top, and from the side. In order to see as much tissue as possible, your breast is squeezed; this makes the maximum amount of tissue “visible” to the X-ray, partially preventing a tumor “hiding” behind overlapping tissue. Still, it’s not perfect; with only those top-to-bottom and side-to-side views, there’s potentially still hiding space for abnormalities.
Digital Tomosynthesis for Breast Cancer Diagnosis: A 3-D X-ray
Digital tomosynthesis (toe-moe-SIN-thuh-sis) is a new type of X-ray that produces a three-dimensional picture. Your breast is GENTLY secured, just enough so that it won’t move; and an X-ray machine rotates in an arc around it, taking 11 different views. The entire process takes about 20 seconds, and delivers no more radiation than a normal mammogram. Those views are sent to a computer, which reconstructs them into a clear 3-D image of your breast. This computer-assisted technology eliminates “hiding places” in your breast, and is especially effective for women with dense breasts: tumors aren’t obscured by regular breast tissue, as they sometimes are with mammograms.
Dr. Daniel Kopans, director of breast imaging at Massachusetts General Hospital and professor of radiology at Harvard Medical School, has been one of the early proponents of digital tomosynthesis. In an interview posted on Mass. General’s Web site, he explains it like this: “Looking at a 2D mammogram is like trying to look through a book with clear pages–you can see the letters, but it is very hard to read them. It is much better if you can read each page individually,” he said.
And how does digital tomosynthesis as a replacement for mammography stack up next to MRIs, which are already seeing increased use? Well, they’re much shorter in duration (20 seconds vs. 30 minutes); are less invasive, as they don’t involve an injection of dye; will certainly cost less; and, most important, studies have proved that they result in many fewer false positives, which is the chief shortcoming of the MRI.
Digital tomosynthesis is currently being tested at five sites around the country as part of the FDA approval process. One of those sites is Dartmouth-Hitchcock Medical Center in Lebanon, N.H. where I had my treatment. Dr. Steven Poplack, co-director of the Breast Imaging Center there–and the doc who did my biopsy–said, in an interview in Dartmouth Medicine magazine, that the diagnostic value of tomosynthesis appears to be "very impressive."
Hey, I’ve about had it with the Big Squeeze–wonder if they’re taking volunteers for tomosynthesis yet? Think I’ll call and find out before my next mammogram’s due.