Unilateral Breast Uptake of 99mTc-MIBI in a Lactating Woman During Myocardial Perfusion Imaging

A 34-year-old woman, who was 11 months postpartum, underwent 99mTc-MIBI myocardial perfusion SPECT imaging for atypical symptomatology with normal baseline electrocardiogram and 2-dimensional echocardiography. She was lactating on and off, preferentially from the right breast. Analysis of the raw images revealed unilateral intense tracer uptake in the right breast region that persisted in the delayed spot views (24-hour postinjection). Although bilateral breast uptake of 99mTc-MIBI may be seen in postpartum scenario, unilateral breast uptake can also occur in patients with preferential lactation from 1 breast as seen in this case and should not be mistaken for pathology.