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"Evidence Based Medicine: Statistics used to describe the probability of a test's accuracy."

Sensitivity - The ability to detect that disease is present.

Specificity - The ability to detect that disease is not present

False Negative - When a diagnostic test indicates no disease when cancer is in fact present.

False Positive - When a diagnostic test indicates the presence of disease when cancer is not actually present.

Breast-Specific Gamma Imaging (BSGI) is a functional or molecular breast imaging procedure that captures the metabolic activity of breast lesions through radiotracer uptake. A small amount of tracing agent is delivered to a patient, and in turn is absorbed by all cells in the body. The tracing agent emits invisible gamma rays, which are detected by the Dilon 6800 Gamma Camera and translated into a digital image of the breast. Due to the higher metabolic activity of cancerous cells, these cells absorb a greater amount of the tracing agent and are revealed as "hot spots." This molecular breast imaging technique can help doctors more reliably differentiate cancerous from non-cancerous cells. While other adjunct modalities, such as MRI and ultrasound, image the physical structure of the breast, BSGI captures the cellular functioning of the breast tissue.

Mammogram ®

BSGI Image (l)

Cancerous lesion not detected by X-ray is revealed with BSGI.

Mammograms are x-rays that image tissue densities, not cancer activity. BSGI with the Dilon 6800 uses radiotracer uptake to help detect cancer independent of tissue density.

BSGI is a valuable tool for situations where mammography is weak and further evaluation is needed, especially when patients have:

• Dense breast tissue
• Multiple suspicious lesions or clusters of microcalcifications
• Palpable lesions not detected by mammography or ultrasound
• Post-surgical or post-therapeutic mass
• Implants
• Been taking Hormone Replacement Therapy

And from surgical and treatment perspectives, BSGI may provide valuable information for the following scenarios:

• Determining extent of the primary lesion
• Detecting occult secondary lesion
• Evaluating the axillary region for node status in breast cancer patients

A patient is intravenously injected with a small dose of sestamibi (Technicium Tc 99m), the same pharmaceutical used in cardiac stress tests safely for over 15 years. Imaging can begin immediately and continue as needed for up to two hours. Patients are seated comfortably throughout the imaging process and each view takes between 6 and 10 minutes to acquire.

MRI has shown usefulness as a next-step imaging modality for difficult-to-diagnose cases. Much like x-ray mammography, breast MRI relies on anatomical or structural information, but provides much more detailed images. It is limited, however, by its highly variable specificity, which can range from below 37% to 97%. Combined with its high sensitivity, MRI produces a high false positive rate. It is also expensive, sometimes difficult to schedule and may require multiple days to complete.

Ultrasound is also commonly utilized as a next-step after a questionable mammogram and is good at determining if a suspect mass is solid or fluid-filled. However, ultrasound demonstrates a low specificity rate that can produce misleading results and indicate biopsy where one may not be needed.

BSGI, as a functional procedure, images cancer activity while both MRI and Ultrasound image tissue structure. Functional imaging allows physicians to see the breast more clearly by accessing a map of cellular metabolism. Certain types of breast tissue may interfere with cancer detection. The need for a complementary diagnostic procedure to mammography is filled by a test that provides for improved sensitivity and specificity - such as BSGI.