Synthesis and Biological Evaluation of SPECT/MRI Dual-modal Imaging Agent SPION-DMSA-RGD-⁹⁹Tc^m

In order to investigate the possibility of SPION-DMSA-RGD-⁹⁹Tc^m as a SPECT/MRI dual-modal imaging agent, SPION-DMSA-RGD and its radiolabeled SPION-DMSA-RGD-⁹⁹Tc^m were prepared. SPION-DMSA-RGD was prepared based on SPION-DMSA and c(RGDfC). SPION-DMSA-RGD was characterized by means of various methods. SPION-DMSA-RGD-⁹⁹Tc^m was given by labeling with ⁹⁹Tc^m. The biodistribution studies of SPION-DMSA-RGD-⁹⁹Tc^m in normal mice and the nude mice bearing U87MG human glioma were performed. The MRI and SPECT imaging of SPION-DMSA-RGD and SPION-DMSA-RGD-⁹⁹Tc^m in the nude mice bearing U87MG human glioma were carried out, respectively. The results show that SPION-DMSA-RGD exhibits super-magnetic properties. The labeling yield of SPION-DMSA-RGD with ⁹⁹Tc^m is about 98%. SPION-DMSA-RGD-⁹⁹Tc^m displays fast clearance from the blood and high accumulation in the liver. The tumor uptake of SPION-DMSA-RGD-⁹⁹Tc^m is higher than that of SPION-DMSA-⁹⁹Tc^m. The MRI and SPECT images show that the tumor active targeting of SPION-DMSA-RGD and SPION-DMSA-RGD-⁹⁹Tc^m are obvious. Therefore, SPION-DMSA-RGD-⁹⁹Tc^m can be acting as a SPECT/MRI dual-modal imaging agent for nude mice bearing U87MG human glioma.