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Breast cancer is the second leading cause of cancer death in women today. It was estimated that 207,090 women would be diagnosed with cancer and 39,480 women would die of breast cancer in 2010 in the United States. For better survival odds and less use of the treatments and therapies and, therefore, fewer side-effects, many imaging systems are continually being developed to diagnose this disease as early as possible. Even though breast self-examinations (BSEs) and clinical breast examinations (CBEs) are affordable options to women, there is a lack of education regarding these methods, and these methods are not capable of detecting the cancer at its earliest stages.
Mammography, which is the most popular technique for breast cancer detection, uses low-dose x-ray, high-contrast, high-resolution detectors, and an x-ray system designed specifically for imaging the breasts. Mammography has found its application in both screening and diagnosis of breast cancer. In the case of screen-film mammography (SFM), the end-recording device is a film screen. Full-field digital mammography (FFDM), on the other hand, uses digital detectors as the recording media. The digital images provided by FFDM offer many advantages over their film counterpart. In FFDM, image enhancement to accentuate pathology is possible (postprocessing) and, because of the acquisition of digital images, CAD software can be used to highlight and detect suspicious areas in the mammograms. In the Digital Mammographic Imaging Screening Trial (DMIST), 49,528 asymptomatic women were evaluated by both SFM and FFDM. Results reported a significantly better detection by FFDM in women of age 50 or younger, premenopausal women, or women with dense breasts. This better detection can be attributed to the improved contrast resolution of digital mammography. An update on digital mammography techniques can be found in Ref. 4. In spite of the use of ionizing radiation that may be potentially harmful on repeated use and its lower sensitivity in detecting cancers in dense breasts, mammography is still the most recommended examination for breast cancer screening and detection. Studies show that mammography can be used for early detection and treatment of breast lesions. However, interpretation of mammograms is a subjective process; hence, interobserver variability is common. Therefore, CAD tools are being developed and studied in order to assist radiologists in relatively better objective interpretation of mammograms.
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