In this paper,the 99mTc-octreotide scintimammography as a useful complementary technique of mammography was evaluated in diagnosing breast cancers.The 45 breast lesions were consecutively detected by mammography,and 99mTc-octreotide scintimammography,and both combination technique on the basis of self-examination,physical examination.Clinical diagnosis was confirmed by histopathologic analysis.Radioactivity uptake ratios for tumor vs normal breast tissues (T/NT) were calculated using regions of interest.In the breast cancer groups and the benign lesion groups,the average uptake ratios of the 99mTc-octreotide were 1.63±0.19 and 1.09±0.13,respectively,and t was 9.638 (P<0.001).Based on sensitivity,specificity,accuracy,positive predicting value,and negative predicting value,99mTc-octreotide scintimammography was 87%,79%,84%,90%,and 73%,the mammography was 65%,64%,64%,80%,and 45%,and both combination was 95%,100%,97%,100% and 92%,respectively.This showed that the 99mTc-octreotide scintimammography was more useful than mammography in the evaluating suspected breast cancers,and the combination technique can accurately discriminate lesions. In this paper, the 99mTc-octreotide scintimammography as a useful complementary technique of mammography was evaluated in diagnosed breast cancers. The 45 breast lesions were consecutively detected by mammography, and 99mTc-octreotide scintimammography, and both both combination techniques on the basis of self-examination , physical examination. Clinical trial was confirmed by histopathologic analysis. Radiosactivity uptake ratios for tumor vs normal breast tissues (T / NT) were calculated using regions of interest. the breast cancer groups and the benign lesion groups, the average uptake ratios of the 99mTc-octreotide were 1.63 ± 0.19 and 1.09 ± 0.13, respectively, and was 9.638 (P <0.001). Based on sensitivity, specificity, accuracy, positive predicting value, and negative predicting value, 99mTc-octreotide scintimammography was 87%, 79 The mammography was 65%, 64%, 64%, 80%, and 45%, and both combination was 95%, 100%, 97%, 100% and 92% respectively. This showed that the 99mTc-octreotide scintim ammography was more useful than mammography in the suspected breast cancers, and the combination technique can accurately discriminate lesions.