Comparative Study of ~(99m)TcN(NOEt)_2 and ~(99m)Tc-MIBI Imaging in Mice Bearing Ehrlich Ascites Tumor

摘要

Objective To evaluate and compare the ability to detect turnor by bis ( N-ethoxy-N-ethyl dithiocarbamato) nitrido ~(99m)Tc( V) [~(99m) TcN(NOEt)_2] and ~(99m)Tc hexakis-2- methoxyisobutyl isonitrile [~(99m)Tc-MIBI]. Methods ~(99m)TcN(NOEt)_2 was prepared and quality control was performed using ascending thin-layer chromatography. Four mice bearing Ehrich ascites tumor cells underwent whole body planar imaging at 30 min, 2 h and 4 h after injection of ~(99m)Tc-MIBI or ~(99m)TcN(NOEt)_2. ROIs were drawn around the tumor, head, chest, and contralateral limbs in whole body planar images, and ratios of radioactivity in tumor in head (T/H) , chest (T/C) , and contralateral limbs (T/L) were calculated. The mice of ~(99m)TcN (NOEt)_2 group were killed, then blood was collected, and the tumor and organs were excised, weighed and the radioactivity was measured. Results ~(99m)TcN(NOEt)_2 was stable after 4h at the room temperature. ~(99m)TcN( NOEt)_2 was delivered to the tumor selectively and efficiently. ~(99m)TcN( NOEt)_2 was found to provide excellent tumor-to-nontumor contrast for all the tissue except the abdomen. The T/L ratios increased to their maximums (4. 87) at 2 h after injection. There was significant difference between the ~(99m)TcN ( NOEt)_2 imaging group and ~(99m)Tc-MIBI imaging group. In vitro the radioactivity ratios per unit weight of tumor to blood, muscle, skeleton, lung, heart, and spleen were much higher than those of tumor to liver, instestine. Conclusion In mice bearing Ehrich ascites tumor, ~(99m)TcN(NOEt)_2 exhibits a set of features essential for a good tracer for tumor imaging, including a rapid washout from blood, high uptake rate in tumor tissue, prolonged retention and high tumor-to-nontumor uptake ratio. The imaging quality of ~(99m)TcN(NOEt)_2 was superior to that of ~(99m)Tc-MIBI. These features indicate that ~(99m)TcN (NOEt)_2 may be a better tracer to detect tumor than ~(99m)Tc-MIBI.