Uptake of 99mTc-MIBI and 99mTc-tetrofosmin into malignant versus nonmalignant breast cell lines

The kinetics and cellular uptake of Tc-99m-2-hexakis 2-methoxyisobutyl-isonitrile (MIBI) and (TC)-T-99m-1 ,2-bis[biS(2-ethoxyethyl)phosphino]ethane (tetrofosmin) into malignant versus nonmalignant human breast cell lines were investigated and compared. Methods: At specific intervals after incubation at 37 degrees C and 22 degrees C with Tc-99m-MIBI or Tc-99m-tetrofosmin, the uptake characteristics of radiotracers into human adenocarcinoma breast cell lines MCF-7 and SK-BR-3 and human breast, nontumor cell line HBL-100 were assessed. Results: The uptake of (TC)-T-99m-MIBI and (TC)-T-99m-tetrofosmin was lower at an incubation temperature of 22 degrees C than that at 37 degrees C in the 3 cell lines. In MCF-7 and in SK-BR-3 cells the uptake of 99mTc-MIBI was significantly higher than the uptake of Tc-99m-tetrofosmin. The uptake of Tc-99m-MIBI was significantly higher into MCF-7 and SK-BR-3 cells than that into HBL-100 cells. In comparison with HBL-100 cells, uptake of (TC)-T-99m-tetrofosmin into SK-BR-3 cells was significantly higher, whereas uptake into MCF-7 cells was similar. Conclusion: In vitro data suggest that (TC)-T-99m-MIBI may be a better tracer than (TC)-T-99m-tetrofosmin for discrimination between malignant and nonmalignant breast disease.