There are two reasons mammograms are taken:
Screening mammograms are done for women who have no symptoms of breast cancer.
Diagnostic mammograms are done when a woman has symptoms of breast cancer or a breast lump. Diagnostic mammograms take longer than screening mammograms, because more pictures of the breast are taken.
In January 2000, the FDA approved a new way of doing mammograms, called digital mammography. This technique records x-ray images on a computer, rather than directly on film. Digital mammography has the following advantages:
Can allow the technician taking the x-ray to make adjustments, such as enhancement, magnification, or other manipulation without having to take another mammogram
Can reduce exposure to radiation, due to reduction of the need for repeat mammograms
Takes pictures of the entire breast, even if the denseness of the breast tissue varies
Compared to film mammography, digital mammography is more sensitive for detection of abnormalities in women with dense breasts, pre-menopausal women, perimenopausal women, and women <50 years of age[1, 2]
1. National Cancer Institute. Digital mammography trial results announced: women with dense breasts, women younger than 50, and those who are perimenopausal may benefit from digital mammograms. Accessed at www.cancer.gov/newscenter/pressreleases/DMISTrelease
2. E. D. Pisano, C. Gatsonis, E. Hendrick, M. Yaffe, et al. Diagnostic performance of digital versus film mammography for breast cancer screening. New England Journal of Medicine. 2005; 353(37):1773-1783.