Just how much more radiation are you getting with these new 3D mammograms? There are different estimates in circulation, partly because some folks are not including the radiation exposure from the standard mammogram into the total. When you add the 2D and 3D scans together, utilizing tomosynthesis at least doubles your radiation exposure, and some estimates have your exposure tripling, such as this 2011 study published in Radiology Today,2 which states that:
"Because the digital breast tomosynthesis (DBT) exam requires two additional exposures over a standard mammogram, the total radiation dose from the combined 2D and tomosynthesis examination is three times that of a standard mammogram."
The authors note that both scans (2D and 3D) are required because studies done prior to FDA approval failed to conclusively show better sensitivity of 3D alone, compared to 2D imaging.3 They also state that it’s too early to know how useful this new breast imaging technology will be. Some insurance companies—Aetna4 for one—have rejected it, citing “insufficient evidence of its effectiveness.”
The bottom line is, the industry reports tomosynthesis has 1.5 to 2 times the radiation dose. The FDA reports it has double the dose. And the radiologists, who are looking at total exposure, report triple the dose over conventional mammograms. You can see this comparison in a chart on page 8 of an FDA Executive Summary, “Average Glandular Dose per Breast.”5
Tomosynthesis is being touted by the industry as being particularly helpful for identifying cancer in women with dense breast tissue. However, these women already have a four to six times greater risk of developing breast cancer. Knowing that ionizing radiation is a direct cause of cancer, how can a test that triples your radiation exposure be of any benefit if you have potentially cancer-prone breasts to begin with?
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