Tumor Locating Property of ⁹⁹Tc^m-MAVGG-glucose

To develop ⁹⁹Tc^m labeled glucose derivatives for imaging tumor with SPECT， β-N-mercaptoacetyl-Val-Gly-Gly-glucose (MAVGG-Glu) was labeled with ⁹⁹Tc^m. The labelled compound was injected into the mice bearing S180 tumors, and biodistribution was measured at 3 h and 5 h postinjection. The biodistribution of ¹⁸F-2-fluoro-desoxy glucose (¹⁸F-FDG) at 5 h postinjection was also studied for comparison. The results showed that ⁹⁹Tc^m labeling yield was greater than 90%. The tumor uptakes at 3 h and 5 h postinjection were 1.46±0.41 and 1.28±0.24%ID/g, respectively. The T/NTs were greater than 1.8 for tumor over all other normal tissues excepted for kidney and liver at 5 h postinjection. T/NT of tumor to blood, tumor to muscle and tumor to brain were 4.41, 4.00 and 8.53, respectively. Tumor was visualized at 3 h postinjection, and the contrast became slightly sharper with time lasted. The results suggested the potential utility of ⁹⁹Tc^m-MAVGG-Glu as a suitable tumor imaging agent. Compared with ¹⁸F-FDG，⁹⁹Tc^m-MAVGG-Glu had lower tumor uptake and T/NTs for most tissues. But its T/NTs for tumor to muscle, heart, spleen and brain, especially for tumor to brain, were higher, which indicated that ⁹⁹Tc^m-MAVGG-Glu may have advantages in imaging brain tumor and the tumor near brain.