The uptake and washout kinetics of two cationic lipophilic 99mTc- labeled myocardial perfusion agents. 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) and 99mTc-1, 2-bis[bis-(2-ethoxyethyl)-phosphino]ethane (99mTc-Tetrofosmin), were studied in cultured smooth muscle cells and compared to the conventional myocardial perfusion agent, 201Tl. Both 99mTc-MIBI and 99mTc-Tetrofosmin had a 4-fold greater uptake than 201Tl, and they were washed out of cells through similar kinetics which had slower rates than 201Tl. Incubation with metabolism inhibitors had a modest influence on the uptake of these two 99mTc-labeled agents, although their extent and inhibited sites were slightly different. Ion transport inhibitors did not affect the uptake of 99mTc-MIBI, although the 99mTc- Tetrofosmin uptake was slightly inhibited when the Ca2+ channel was blocked. Our studies indicate that 99mTcMIBI and 99mTc-Tetrofosmin were taken up by smooth muscle cells in similar pharmacokinetic patterns, but their accumulation reflected a different meaning for cell viability.
- smooth muscle cells
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging