Investigation of ~(99) Tc~m-MIBI Imaging in Differential Diagnosis of Breast Masses and in Detection of Metastatic Axillary Lymph Node

Objective To evaluate prospectively the sensitivity and specificity of 99 Tc m MIBI scintimammography in the differential diagnosis of breast masses and the metastasis axillary lymph node in breast cancer. Methods The 555～750MBq 99 Tc m MIBI was injected into an antecubital vein contralateral to the palpable breast lesion.The early and delay images were acquired at 15min and 1.5h after injection of the tracer.The imaging was performed using special designed imaging device made by ourselves.Three planar views,right and left lateral and anterior views including both axillae were obtained.The acquisition counts should be reached 1000k. Results Of the 34 cases,22 patients' 99 Tc m MIBI images were positive,and 12 images negitive.There were 20 true positive,4 false negitive in 24 malignants imaging.And 2 false positive,8 true negitive in 10 benigns.The sensitivity of 99 Tc m MIBI images in diagnosis of breast cancer was 83.3%,and the specificity was 80.0%,the positive and the negative predictive values were 90.9% and 66.7%,the accuracy was 82.4%.The sensitivity of scintimammography in detecting metastatic axillary lymph node was 80.0%,and the specificity was 92.9%,the positive and the negative predictive values were 88.9% and 86.7%,the acuracy was 87.5%. Conclusion 99 Tc m MIBI images provides clinically valuable information on patients with palpable breast masses. 99 Tc m MIBI scintigraphy of breast can well differential between malignant and benign masses,but the sensitivity for lesions was related to the tumor size in some degree.