RADIONUCLIDE-GUIDED STEREOTAXIC PREBIOPSY LOCALIZATION OF NONPALPABLEBREAST-LESIONS WITH NORMAL MAMMOGRAMS

Scintimammography with Tc-99m-sestamibi can be used as a complementary technique to improve the mammogram's sensitivity and specificity for detection of breast carcinoma. We have observed in some patients focal areas of increased Tc-99m-sestamibi uptake with no corresponding abno rmalities on physical examination or mammogram. A phantom device and a special needle were designed to stereotactically localize these lesio ns before biopsy. Methods: After intravenous injection of 30 mCi (1110 MBq) of Tc-99m-sestamibi, a prone lateral image of the abnormal breas t was obtained. With the patient in the prone position, the breast was compressed with two fenestrated plates in the prone position. The x a nd y coordinates of the abnormal hot spot of the breast were determine d. The z coordinate of focal (99m)-sestamibi uptake was determined by advancing a localizer needle through a selected predetermined hole of the fenestrated plate using real-time visualization on the persistence monitor. The tip of the opturator inside the needle is welded with Co -57 to determine the depth of the hot spot in the breast. Results: Thr ee women, all of whom had normal mammograms and breast physical examin ations, were studied using Tc-99m-sestamibi prone breast imaging. Pre- excisional biopsy needle localization of abnormal focal uptake was per formed, Two women demonstrated infiltrative ductal carcinoma, and the third had proliferative fibrocystic disease of the breast. Conclusion: Our initial experience demonstrates that nuclear medicine-guided ster eotactic needle biopsy of the breast in patients with positive scintim ammograms is technically feasible. In the future, this technology will enable us to detect breast carcinoma in the absence of clear-cut clin ical and mammographic findings.