Scintimammography with Tc-99m MIBI in patients with suspicion of primary breast cancer.

The aim of the study was to evaluate the diagnostic accuracy of scintimammography with Tc-99m MIBI for the detection of breast cancer. Patients with a suspicious lesion detected by palpation or mammography were included in the study. Excisional biopsy was performed on all patients. Mammography was performed within 3 weeks prior to scintigraphy. All patients received 740 MBq Tc-99m MIBI intravenously in the arm contralateral to the suspicious breast and were subsequently examined in a prone position. At 5 to 10 min postinjection, planar images were obtained in lateral and anterior views, with an acquisition time of 10 min each. After planar imaging, a SPECT study was performed using a two-head camera. Breast cancer was confirmed in 29 out of 68 patients. The tumor size ranged from 6 to 90 mm in diameter. For scintigraphic studies, the overall sensitivity and specificity was 83% and 84%, respectively. However, sensitivity for palpable lesions was 100%. The smallest detectable tumor measured 9 mm in diameter and could be visualized only in the planar scintigram. Using Tc-99m MIBI, axillary lymph node metastases could be detected with a sensitivity of 82%. Scintigraphy with Tc-99m MIBI has a high diagnostic accuracy for the detection of primary breast cancer in patients with a palpable mass. Scintimammography may be used as a complementary method to mammography and help to decrease the number of unnecessary breast biopsies.