Digital Mammography
What is Mammography?
Mammography is a specific type of imaging that uses a low-dose x-ray system to examine breasts. A mammography exam, called a mammogram, is used to aid in the early detection and diagnosis of breast diseases in women. Digital mammography, used by Redwood Regional Medical Group, and also called full-field digital mammography (FFDM), is a system in which detectors convert x-rays into electrical signals. These detectors are similar to those found in digital cameras. The electrical signals are used to produce images of the breast that can be seen on a computer screen.
What are some common uses of the procedure?
Mammograms are used as a screening tool to detect early breast cancer in women experiencing no symptoms and to detect and diagnose breast disease in women experiencing symptoms such as a lump, pain or nipple discharge.
There are two types of mammograms:
Screening Mammography
Mammography plays a central part in early detection of breast cancers because it can show changes in the breast up to two years before a patient or physician can feel them. Current guidelines from the U.S. Department of Health and Human Services (HHS), the American Cancer Society (ACS), the American Medical Association (AMA) and the American College of Radiology (ACR) recommend screening mammography every year for women, beginning at age 40. Research has shown that annual mammograms lead to early detection of breast cancers, when they are most curable and breast-conservation therapies are available.
The National Cancer Institute (NCI) adds that women who have had breast cancer, and those who are at increased risk due to a genetic history of breast cancer, should seek expert medical advice about whether they should begin screening before age 40.
Diagnostic Mammography
Diagnostic mammography is used to evaluate a patient with abnormal clinical findings-such as a breast lump or lumps that have been found by the woman or her doctor. Diagnostic mammography may also be done after an abnormal screening mammogram in order to evaluate the area of concern with special views.
How does the procedure work?
X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small burst of radiation that passes through the body, recording an image on a special digital image recording plate.
Different parts of the body absorb the x-rays in varying degrees. Dense bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow more of the x-rays to pass through them. As a result, bones appear white on the x-ray, soft tissue shows up in shades of gray and air appears black.
Until recently, x-ray images were maintained as hard film copy (much like a photographic negative). Today, at Redwood Regional Medical Group images are digital files that are stored electronically. These stored images are easily accessible and are sometimes compared to current x-ray images for diagnosis and disease management.
How is the procedure performed?
During mammography, a specially qualified radiologic technologist will position your breast in the mammography unit. Your breast will be placed on a special platform and compressed with a paddle. The technologist will gradually compress your breast. Some women with sensitive breasts may experience discomfort. If the discomfort is significant, less compression will be used.
Breast compression is necessary in order to:
- Even out the breast thickness so that all of the tissue can be visualized.
- Spread out the tissue so that small abnormalities are less likely to be obscured by overlying breast tissue.
- Allow the use of a lower x-ray dose since a thinner amount of breast tissue is being imaged.
- Hold the breast still in order to minimize blurring of the image caused by motion.
- Reduce x-ray scatter to increase sharpness of picture.
You will be asked to change positions between images. The routine views are a top-to-bottom view and an oblique side view. The process will be repeated for the other breast.
You must hold very still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image. The technologist will walk behind a leaded wall to activate the x-ray machine.
With digital technology, the technologist will be able to verify that the images are clear as she completes the procedure, rather than make the patient wait for film development as in the past.
The examination process should take about 10-15 minutes.
When should I schedule my exam?
Try not to schedule your mammogram for the week before your period if your breasts are usually tender during this time. The best time for a mammogram is one week following your period.
How should I prepare?
Before scheduling a mammogram, it's important to discuss any new findings or problems in your breasts with your doctor. In addition, let your doctor know of any prior surgeries, hormone use, and family or personal history of breast cancer. Always inform your doctor or radiologic technologist if there is any possibility that you are pregnant.
- Do not wear deodorant, talcum powder or lotion under your arms or on your breasts on the day of the exam. These can appear on the mammogram as calcium spots.
- Describe any breast symptoms or problems to the technologist performing the exam.
- Tell the technologist if you have breast implants.
- If possible, obtain prior mammograms and make them available at the time of the current exam.
Who interprets the results and how do I get them?
A Radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
You will also be notified of the results by the mammography facility by mail within 1-2 weeks.
What are the benefits vs. risks?
Benefits
- Imaging of the breast improves a physician's ability to detect small tumors. When cancers are small, the woman has more treatment options and a cure is more likely.
- The use of screening mammography increases the detection of small abnormal tissue growths confined to the milk ducts in the breast, called ductal carcinoma in situ (DCIS). These early tumors cannot harm patients if they are removed at this stage and mammography is the only proven method to reliably detect these tumors. It is also useful for detecting all types of breast cancer, including invasive ductal and invasive lobular cancer.
- While it is possible that mammography may miss a small percentage of cancers, it is still the best and only consensus general screening method currently available.
Risks
- There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. (No radiation remains in a patient's body after an x-ray examination and X-rays usually have no side effects in the diagnostic range.)
- The effective radiation dose from a mammogram is about the same as the average person receives from background radiation in three months. Federal mammography guidelines require that each unit be checked by a medical physicist every year to ensure that the unit operates correctly.
- Five to fifteen percent of screening mammograms require more testing such as additional mammograms or ultrasound. Most of these tests turn out to be normal. If there is an abnormal finding, a follow-up or biopsy may have to be performed. Women should always inform their physician or radiologic technologist if there is any possibility that they are pregnant.