Radiolabeled molecules have an important role to evaluate tumor characteristics such as aggressiveness, and to identify the effectiveness of cancer treatments such as chemotherapy and radiotherapy. Various radionuclide (F-18, Tc-99m, I-124) labeled molecules can be used apoptosis detection by estimating decrescendos cell viability after therapy. Tc-99m-tetrofosmin which is used as a myocardial perfusion imaging agent in routine and at the same time is known to accumulate in various tumors including breast tumor. The aim of this study was to assess the utility of Tc-99m-tetrofosmin for monitoring the early response of MCF-7 breast cancer to chemotherapy. To evaluate the role of Tc-99m-tetrofosmin in vitro chemotherapy, the uptake ratio was determined using MCF-7 breast cancer line after the cells had been treated with cisplatin. When we examined the apoptotic ratios which induced with different dose of cisplatin in MCF-7 breast cancer cells by using Annexin V and TUNEL methods, it was observed that the rate of apoptosis increased with soaring dose. The uptake rates of Tc-99m-tetrofosmin in MCF-7 cell line in the chemotherapeutic groups were lower than it is in the control group (p < 0.01). The negative correlation between uptake ratios and apoptotic rates shows that Tc-99m-tetrofosmin may be used a radiopharmaceutical for evaluating chemotherapy response. Tc-99m-tetrofosmin might be probably useful as an imaging agent for estimation of early chemotherapy response in breast cancer.