3-D mammography could lead to earlier detection of breast cancer
Susan C. Harvey, a clinical associate in radiology at the School of Medicine and director of Breast Imaging in the Russell H. Morgan Department of Radiology and Radiological Science at the Johns Hopkins Hospital
"This amazing 3-D image came from our new Dimensions Hologic mammography unit at Johns Hopkins Health Care and Surgery Center at Green Spring Station. The machine has the ability to perform both traditional 2-D digital mammography and 3-D mammography—technology that is revolutionizing breast imaging. The upper part of the X-ray tube traverses 15 degrees across the breast taking 15 low-dose images that are then reconstructed into 1 mm slices.
"In the past, the X-ray beam took only one image in each plane, leading to a 2-D image that superimposed all the breast tissue onto that one image. This superimposed tissue could hide cancers, and have areas of normal tissue that overlapped and mimicked cancers. This new ability to sort out normal tissue from abnormal findings promises a decrease in false positives and a higher accuracy of cancer detection. This is a great advance. The unit was installed in late March, and our first patients had 3-D mammograms on April 4.
"When I began my breast-imaging fellowship, images were all obtained on film. We had a darkroom and actual film that we hung on lighted viewing stations for interpretation. There was no ability to alter the image once it was taken. The image was static. Then digital imaging was developed and put into clinical use in the early 1990s.
"The promise of 3-D mammography is earlier detection of breast cancer. If breast cancers are diagnosed and treated before they can spread to the nodes under the arm, or axilla, the five-year survival rate is over 98 percent. Detected early, breast cancer survival is not only improved but may require less-aggressive surgery and often with no chemotherapy needed.
"The incidence of breast cancer is rising, and the mortality from breast cancer is declining. We expect over the next few years, with the use of 3-D mammography, we will see more women treated and living longer. We endeavor to keep the promise to make breast cancers curable. That is a tall order, but we have to start somewhere."