Technetium-99m tetrofosmin scintigraphy in the diagnosis of breast cancer.

The routine mammogram remains the procedure of choice for screening asymptomatic women for breast cancer. However, it accounts for an elevated percentage of misdiagnosed breast nodules particularly in younger women with dense breast tissue or fibrocystic disease. New radiopharmaceuticals including labelled monoclonal antibodies, thalium-201 and technetium-99m sestamibi are under investigation as possible solutions to this issue. 99mTc-tetrofosmin (Myoview), like 99mTc-sestamibi, is a lipophilic, cationic myocardial imaging agent. Mitochondrial membrane potential appears to play a significant role in the uptake and/or retention of 99mTc-tetrofosmin. Twenty-seven female patients with suspected breast cancer were included in the study. Twenty mCi of 99mTc-tetrofosmin were administered intravenously. Imaging was begun 10 min post-injection. In twenty-three patients, breast cancer was detected using 99mTc-tetrofosmin scintigraphy. Two carcinomas were missed. In two patients, both breast scintigraphy and intraoperative biopsies were negative. Our preliminary results suggest that this product may have a role in the differentiation of benign from malignant lesions, and were encouraging in terms of its potential usefulness as a marker of malignancy.