[Comparative evaluation of 99mTc-MIBI (hexakis2-methoxy isobutyl isonitrile) and 201Tl-chloride in primary lung...

We performed comparative study, using 99mTc-MIBI and 201Tl-chloride in patients with primary lung cancer. There were 42 patients with primary lung cancer. All patients underwent dual radionuclide imaging with 201Tl-chloride and 99mTc-MIBI. Regions of interest were placed over the tumor area (T) and contralateral normal lung area (N). A tumor to normal lung ratio (T/N ratio) and retention index were calculated by early and delayed ratios. In the SPECT images, the positive rate was 98% in both the early and delayed images for 201Tl-chloride and 95% in the early and 88% in the delayed images for 99mTc-MIBI. Both early and delayed T/N ratios of 201Tl-chloride were significantly higher than those of 99mTc-MIBI. The retention index of 201Tl-chloride was higher than that of 99mTc-MIBI. T/N ratio and retention index did not significantly correlated with reference to histological types. We conclude that 99mTc-MIBI SPECT can be helpful in localizing primary lung cancers. However, in our study the tumor accumulation of 99mTc-MIBI was significantly lower compared with 201Tl-chloride.