Breast-Specific Gamma Imaging

Abstract

In the United States, breast cancer is the most common cancer in women and the second most common cause of cancer death in women after lung cancer. 1 Breast cancer is associated with significant morbidity, mortality, and health care expenditure. When breast cancer is diagnosed in its earliest stages, it is a curable disease, with a 5-year survival of more than 90%. 1 Therefore, an annual screening mammogram in women, starting at 40 years of age in women with no family history and earlier in women with a family history of breast cancer, is the current standard-of-care recommendation by the National Cancer Institute.Mammography, the gold standard in breast cancer detection, results in up to 30% reduction in breast cancer mortality. 2 Mammography uses high-resolution radiography that evaluates breast anatomy to detect density, distortion, asymmetry, and calcifications. However, there are challenges in mammographic interpretation. One such challenge lies in eval-uation of dense breast tissue, because an increased density in the breast on mammography is a typical appearance of breast abnormality. Another challenge of mammographic evaluation is posed by overlapping breast tissue, causing summation of shadows that can mimic abnormal density or architectural distortion. These factors lower the sensitivity of mammography. Because mammography relies solely on the anatomic appearance of an abnormality, only 20% to 30% of biopsied suspicious mammographic lesions are found to be true breast malignancies. Mammography cannot definitively differentiate between benign and malignant lesions. Furthermore, 10% to 15% of breast cancers are mammographically undetectable.From 10% to 15% of breast cancers are mammographically undetectable, and only 20% to 30% of biopsied suspicious mammographic lesions are found to be true breast malignancies.Breast sonography, the second most commonly used technology for cancer detection, is considered a complement to the mammographic evaluation. Similar to mammography, sonography facilitates evaluation of the breast anatomy. Evolution of Breast-Specific Gamma ImagingScintimammography was incidentally discovered in 1992 during cardiac imaging with 99m technetium sestamibi in a patient with breast cancer. 4