The breast cancer cell line MCF7 as a model of 99mTc-SestaMIBI, 99mTc-tetrofosmin and 99mTc-Medronate incorporation.

Hexakis-2-methoxyisobutylisonitrile (SestaMIBI) and 1,2-bis[bis(2-ethoxyethyl)phosphino]ethane (tetrofosmin) are 99mtechnetium compounds widely used in oncologic imaging. We investigated the uptake and release of SestaMIBI and tetrofosmin together with 99mTc-medronate in the MCF7 breast carcinoma cell line. All the tracers showed similar uptake kinetics, with a rapid increase in the first 30 minutes and a slower trend up to 120 minutes. Cell-associated activity was the same for SestaMIBI and tetrofosmin (4% of administered activity) and considerably lower for medronate (0.8%). For all tracers, almost all the accumulated activity was released within 1 hour. Furthermore, to verify an association between cell proliferation and tracer uptake, we performed growth-curve uptake experiments. Tetrofosmin uptake was lower in the logarithmic phase and higher in the plateau phase, whilst SestaMIBI showed the opposite trend. The differences between the tracers could be due to a relationship between proliferation and SestaMIBI uptake, or even to the influence of medium pH on membrane potential.