scintimammography

Scintimammography, also known as breast scintigraphy or scintimammography with Tc-99m sestamibi, is a nuclear medicine imaging technique that visualizes functional activity in breast tissue. It uses intravenously administered radiopharmaceuticals that localize in hypermetabolic malignant tissue, allowing gamma cameras to detect radiotracer uptake. The most commonly used agent is technetium-99m labeled sestamibi; other radiotracers have been used historically.

During the study, a radioactive tracer is injected and images of the breast are acquired with a gamma camera. Imaging may include planar views and, increasingly, single-photon emission computed tomography (SPECT) to improve localization. The procedure is generally well tolerated; the radiation dose is low and comparable to other diagnostic nuclear medicine procedures.

Interpretation focuses on focal uptake that exceeds background activity, which may indicate malignancy but is not specific. Benign processes such as inflammation, infection, post-surgical scar, and implants can produce uptake and cause false positives. Small lesions and certain tumor subtypes may yield false negatives. Correlation with anatomic imaging (mammography, ultrasound, MRI) and, when indicated, biopsy is essential.

Indications include evaluation of breast lesions when mammography is inconclusive or limited by dense breasts, assessment of suspected recurrence after treatment, and characterization of palpable abnormalities when conventional imaging is negative or equivocal. Scintimammography has declined in some settings with the advent of higher-resolution modalities and dedicated molecular breast imaging.

Strengths of the technique include functional information and utility in selected scenarios, while limitations include limited spatial resolution, variable specificity, and reliance on radiotracer uptake. Related approaches include breast-specific gamma imaging (BSGI) and molecular breast imaging.