A digital mammogram differs from a film mammogram in that it uses a special detector to capture and convert x-ray energy into a digital image. The procedure and appearance of the machine and even the images produced are very similar to a traditional film mammogram—the advantage really comes from the ability to manipulate the image electronically.
Digital mammography offers a number of practical advantages and patient conveniences:
- Because there’s no waiting for film to be developed, digital images are immediately available. The technologist can evaluate the quality of the images as they’re taken. That means patients spend less time in the exam room and rarely need to return for repeat images due to under or over exposures.
- The digital machine is fast, so patients spend less time in uncomfortable positions.
- Brightness, darkness, or contrast can be adjusted and sections of an image can be magnified after the mammogram is complete making it easier to see subtle differences between tissues. The ability to increase contrast when imaging dense tissue is particularly important, as dense breast tissue and malignant cells both appear to be white on a film mammogram.
- Digital images are easily stored and retrieved.
- Transmission of images from one physician to another is quick and easy.
- Digital technology provides a platform for new technologies, such as CAD software, dedicated to advancing the early detection of breast cancer.
All mammograms work by sending X-rays through the breast tissue to obtain images. These pictures are then analyzed for abnormalities and assessed for changes from previous tests. Whether your doctor recommends a film or digital mammogram, the experience will be the same.
To get the best images possible in either a film or digital mammogram, the technologist needs to flatten and compress the breasts before taking images. Breasts will be flattened between two special plates before X-rays are used to take the image. For both types of mammograms, the entire test lasts about 20 minutes.
X-rays have been used for nearly a century to detect breast cancer. But the modern-day film mammogram was invented in 1969. In this procedure, images are recorded on film much in the way a traditional film camera takes pictures.
In a digital mammogram, X-rays are still used. But they are turned into electric signals that can then be stored in a computer. This is similar to the way digital cameras take and store pictures.
Breast cancer is the second most common cancer in women in the world.
Fortunately, deaths caused by breast cancer have declined over the past 20 years. Many experts believe this is, in part, a result of improved screening and treatment techniques. Digital Mammograms are the preferred diagnostic test to find breast cancer in its early stages. They do this by using X-rays to scan the breasts for cancer.
How do rates of detecting breast cancer compare for film and digital mammograms?
Although film mammograms are very effective, some research suggests that they may miss between 10% and 20% percent of breast cancers.
A study published in the New England Journal of Medicine compared digital mammograms to film mammograms. The study involved 49,000 women in North America with no known signs of breast cancer. The women were screened using both digital and film mammograms at the beginning of the study and again one year later. Breast cancer was found in 335 of the women. The researchers determined that digital mammograms were superior to film mammograms for three groups:
- women under 50 years of age
- women with dense breasts
- women who have not yet gone through menopause, or who have been in menopause less than one year.
Digital mammograms did not prove to be more beneficial for post-menopausal women over age 50 that do not have dense breasts. Additionally, both forms of mammogram had the same rate of false positives.
It cannot be told from the study whether the increased use of digital mammography over film mammography would result in fewer deaths. However, the researchers did note that the types of cancer caught by digital mammograms after being missed on film are the forms of the disease that can be fatal.