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-ethoxyeth yl)phosphino]ethane (tetrofosmin) are (99m)technetium compounds widely used in oncologic imaging. We investigated the uptake and release of SestaMIBI and tetrofosmin together with Tc-99m-medronate in the MCF7 breast carcinoma cell line. All the tracers showed similar uptake kinetics, with a rapid in crease in the first 30 minutes and a slower trend up to 120 minutes. Cell-a ssociated activity was the same for SestaMIBI and tetrofosmin (4% of admini stered activity) and considerably lower for medronate (0.8%). For all trace rs, almost all the accumulated activity was released within 1 hour. Further more, to verify an association between cell proliferation and tracer uptake , we performed growth-curve uptake experiments. Tetrofosmin uptake was lowe r in the logarithmic phase and higher in the plateau phase, whilst SestaMIB I showed the opposite trend. The differences between the tracers could be d ue to a relationship between proliferation and SestaMIBI uptake, or even to the influence of medium pH on membrane potential.