Assessment of resistance to paclitaxel of murine tumors by 99mTc-MIBI/201Tl dual-radionuclide imaging

This study investigated P-glycoprotein (Pgp) expression by murine tumors with and without resistance to paclitaxel and the role of 99mTc-2-methoxyisobutylisonitrile (MIBI)/201Tl imaging in predicting the effect of paclitaxel. Antitumor effect of paclitaxel and biodistribution of the radiopharmaceuticals were evaluated in mice bearing four tumor types. Pgp expression did not correlate with the antitumor efficacy of paclitaxel. Although the absolute uptake of 99mTc-MIBI did not correlate with Pgp expression, 99mTc-MIBI could predict paclitaxel sensitivity by its higher uptake