Introduction. It would be desirable to have preoperativemethods that allow an adequate selection ofpatients with breast lesions to rule out breast cancer.The aim of the present study is to evaluate theefficiency of preoperative Sestamibi gammagraphyand Doppler sonography regarding the differentialdiagnosis of malignancy in breast lesions.Material and methods. A prospective observationalstudy was conducted on 88 consecutive patientswith breast lesions. All the patients underwent preoperativeDoppler sonography with an echo-enhancingagent and Sestamibi gammagraphy. All thepatients had histopathological study of the surgicalspecimen to compare with the result of the preoperativetechniques. These comparations were doneboth for the overall series and separately for palpableand non-palpable lesions.Results. In the overall series results, both tests separatelyand the two combined, are related significantlyto the malignant histological diagnosis (p <0.001). In palpable lesions, there is a considerableincrease in sensitivity, and especially in specificity,attaining 100%, with the combination of both tests.In non-palpable lesions, a relationship was onlyfound between the results of the Sestamibi gammagraphyand the malignant histological diagnosis(93.3%; p < 0.05).Conclusions. Sestamibi gammagraphy and Dopplersonography are two efficient exploratory techniquesin the preoperative assessment of malignancy inbreast lesions, especially for palpable lesions, andthis efficiency is greater when they are combined