|The amount of radiation breasts receive during a mammogram has been known for some time, but Emory University researchers are the first to precisely compute the overall amount of radiation mammograms deliver to the entire body and also to specific organs, including lungs, eyes, ovaries and uterus.
The scientists found that mammograms deliver very low levels of radiation to the organs and tissues outside the primary x-ray field, including the uterus, which means a fetus would receive an equally low dose of radiation as well.
Results of the study are published online in the journal Radiology.
The research was conducted at Emory University School of Medicine by Ioannis Sechopoulos, PhD, assistant professor of radiology and Andrew Karellas, PhD, former Emory professor currently at the University of Masschusetts Medical Center. Other investigators included Carl D'Orsi, MD, Emory professor of radiology and director of the Breast Imaging Center, Sankararaman Suryanarayanan, PhD, and Srinivasan Vedantham, PhD.
Using a three-dimensional virtual human, researchers tailored the computerized body to include specific anatomical parts, such as the eyes, lungs, uterus and heart, and then mathematically specified the partsÕ individual traits, such as shape, tissue type and distance from the source of radiation.
"We came up with all the data to calculate radiation dose to all parts of the body, including the fetus," says Dr. Sechopoulos. "Thus, we can with great confidence tell a woman that if she did have a mammogram, and it turned out she happened to be pregnant, the radiation dose to the fetus is miniscule. It's not a big concern at all and is equal to perhaps a couple of days of background radiation that one would get naturally."
It is important for clinicians to have accurate knowledge of how much radiation the breasts and other areas of the body receive during imaging procedures, because this information helps determine the appropriate imaging procedure for each patient, says Dr. Karellas.
"With proper management of radiation dose through accurate dosimetric information and good communication between medical physicists and physicians, the radiation dose and risks to patients can be minimized," he says.
"A small percentage of women do not know they are pregnant when they have mammograms," adds Dr. Karellas. "Many women return after discovering they are pregnant and ask how much radiation the fetus received. The answer is a very small amount. But we looked through literature and found little information about actual measurements. So, we decided to compute not only how much radiation the fetus receives during a mammogram, but also the amount of radiation other parts of the body receive."
Using Emory's new high-performance computational cluster the Emory researchers and their collaborators also are exploring the level of radiation patients receive from two new types of breast imaging techniques, known as digital tomosynthesis and dedicated computed tomography. Although not yet commercially available, these techniques may someday provide clinicians with more detailed views of breast tissue than ever before.
This study was supported in part by a National Institutes of Health grant from the National Institute of Biomedical Imaging and Bioengineering and by the Georgia Cancer Coalition.