Picture this: the newest in breast imaging technology

By Arushi Sinha

Mammography‚ the imaging of breast tissue‚ remains one of the most important tools in early breast cancer detection. Traditional mammography uses low-dose X-ray to take a picture of the breast‚ looking for signs of malignancy. The picture‚ which shows contrasts of black and white‚ makes detection of tumors in women with dense breasts more difficult. In addition‚ the technology sometimes has difficulty identifying small tumors.

Digital Mammography
The latest in breast imaging technology‚ digital mammography is taken like a traditional mammogram but makes use of the latest in digital photography and computer technology for spotting potential tumors and recording and transmitting data. Digital mammography harnesses computers and specialized digital cameras to record X-rays on digital film that can then be manipulated to allow for more precise understanding of the image. The first digital mammography system received U.S. Food and Drug Administration (FDA) approval in January 2000.

Once taken‚ the digital mammogram can be stored or sent almost simultaneously to various doctors‚ making second opinions easier and faster. Digital mammograms also make tracking a suspicious area easier since new pictures can be compared with previous tests. Finally‚ digital images‚ unlike film X-rays‚ can zoom in on a particular area. Increasing contrast or adding color can also make suspicious areas more visible.

Often‚ the digital imaging technology is paired with sophisticated software that can bring suspicious areas to the radiologist’s attention. The software‚ called CAD‚ or computer-aided detection‚ uses laser beams to scan the mammogram and convert it into information that is processed by high-speed computers.

Grace Hall‚ 69‚ of Los Angeles‚ decided to participate in a clinical trial of digital mammography at the University of California Los Angeles Jonsson Cancer Center after two of her close friends were stricken with breast cancer. Since then‚ Hall has been vigilant about being screened. “The process was very interesting‚” says Hall. “With a regular mammogram‚ lesions on X-ray film may be so small‚ you can hardly see them. With a digital mammogram‚ it is much easier‚ and so you have to go only once.”

Phil Evans‚ MD‚ director of breast imaging at University of Texas Southwestern Medical Center‚ Dallas‚ explains‚ “With film‚ what you see is what you get‚ but with digital you can tune it just like you would adjust the picture on a television set.”

One potential advantage of these new imaging techniques is cost savings associated with second opinions. “It’s expensive to have double reading‚ so the system functions like a second reader.”

Dr. Evans says if CAD software reviewed all the screens‚ 10-15% more cancers could be detected.

The National Cancer Institute (NCI)‚ Bethesda‚ Maryland‚ reports that despite the advantages digital mammography offers‚ studies have not as yet proven the technology is more effective in finding cancer than conventional mammography‚ and more studies are needed.

Magnetic Resonance Imaging
While use of traditional mammography remains popular‚ both traditional and digital methods have drawbacks.

“You have to have breast compression to increase the resolution and lower the X-ray dosage. This can cause pain and discomfort in some women‚” says Dr. Evans.

Magnetic resonance imaging (MRI) is a newer technique that takes about an hour and causes less discomfort. At the forefront of MRI in breast imaging is Steven Harms‚ MD‚ director of imaging research at the University of Arkansas‚ who has developed the RODEO (ROtating Delivery of Excitation Off-resonance) MRI using a modified version of the regular MRI machine. Available at only a few U.S. sites‚ RODEO is less expensive than a standard MRI machine‚ but still not financially feasible for all locations.

During the RODEO MRI‚ the patient lies on her stomach while a magnetic field moves below. A dye may also be injected into the patient‚ making potential tumors easier to see.

“Cancers have more capillaries and—moreimportantly—abnormally formed capillaries‚ allowing the MRI to see the cancers when standard mammography cannot‚” he explains. “With MRI technology‚ a cancer will stand out like a light bulb.”

The MRI is also more accurate‚ says Dr. Harms‚ explaining that in studies‚ mammography picked up only half the cancers found with the MRI. In addition‚ MRI technology also limits inaccurate test results.

The MRI false-positive rate is lower‚ says Dr. Harms‚ meaning that patients are spared undue anxiety and further unnecessary testing.

Dr. Evans says‚ “The newer imaging technologies are also good for evaluating implants for leakage‚ which becomes important for monitoring women who may have had reconstructive breast surgery.”

“Is it a leak or is it a lump?” asks Dr. Harms‚ explaining that with MRI it is possible to be highly accurate.

Many New Options
Several additional options are on the horizon for detecting potential tumors. Another new tool‚ known as the mammotome‚ or vacuum-assisted biopsy‚ allows for easier biopsies of suspicious lesions found on mammography. After the physician locates the suspicious lesion using mammographic or ultrasound guidance‚ he or she makes a small incision in the breast and inserts a probe. Through a gentle vacuum action‚ the mammotome draws the breast tissue into the hollow chamber of the probe.

“You can take several cubic centimeters worth of tissue or even remove small tumors‚” says Dr. Harms of the new technology.

Since tumors use more glucose than normal breast tissue‚ positron emission tomography‚ or PET scanning‚ can detect tumors in breasts by photographing sugar use in breast tissue. In addition to detection‚ PET scans can also monitor tumor shrinkage after chemotherapy. “We’re really just beginning to learn what it can do‚” Dr. Evans says. “It may help monitor lymph nodes or other parts of the body to see if the cancer has traveled.”

Technological expense is another factor to be considered for new technologies. “Digital mammography costs five to seven times that of the standard mammography unit‚” says Dr. Evans. MRI technology is similarly expensive. “Compared to traditional mammography‚ it is 10 times the price for an MRI‚” estimates Dr. Harms.

Dr. Evans says these new technologies may be suitable for high-risk patients. “Preliminary results show that it finds more cancer in high-risk women‚ such as those who have cancer in one breast or carry a genetic risk.”

The newer technologies such as digital mammography might make those large‚ unwieldy X-rays a thing of the past.

Finding cancer early is half the battle in fighting the disease. Explains Dr. Harms‚ “We probably save their lives since we picked up the cancer in the early stages.” Whether a woman gets a digital mammography or a more traditional form of mammogram‚ experts still agree regular screening is key in keeping cancer at bay.

Trial participant Hall says‚ “I believe in prevention. Anything for getting an improvement is worthwhile.”

Clinical Trial Information: For those interested in enrolling in the digital mammography clinical trials‚ visit www.dmist.org or call 800-422-6237 to find a location nearest you.