Abstract: In this study, the uptake of ^99mTcN-MIBIand₉₉mTc-MIBIwere investigated by colorectal cancer cell line CL-187, lung cancer cell line L-973 and breast cancer cell line MCF-7 in vitro, respectively.The results of uptake kinetics shows that ^99mTcN-MIBI has maximal accumulations between 20 and 40 min after incubation in all of these tumor cells, and the accumulation(D%) of ^99mTcN-MIBIwas found to be significantly higher than that of ^99mTc-MIBI, especially in colorectal cancer cell line CL-187. Up take of ^99mTcN-MIBIdecreased in the order MCF-7→CL-187→L-973. The maximal accumulation occurring at 40 min after incubation of₉₉mTcN-MIBI in MCF-7 with the uptake rate about 30% per 10⁵cells.The influences of the culture conditions, such as cell concentration and incubation temperature, on the accumulation were also investigated, and the uptake of ^99mTc-complexes by cells were affected significantly by the culture conditions.

Key words: ^99mTcN-MIBI, ^99mTc-MIBI, Tumor imaging, Tumor cell, Radiopharmaceuticals