DMSA-coated Fe3O4 nanoparticles were synthesized by wet-chemical method. The chemical interaction between Fe3O4 and DMSA were investigated by FTIR. They were directly radiolabeled with 99mTc radioisotope (Fe3O4@DMSA–99mTc) at room temperature in the presence of stannous solution as a reducing agent. Magnetic and structure properties of Fe3O4@DMSA–99mTc nanoparticles were investigated by AGFM, TEM, and XRD. Biodistribution and toxicity assessment of Fe3O4@DMSA–99mTc were studied in mice by intravenous and intraperitoneally injections, respectively. Blood, kidney, and liver factors were
measured 4 days post injection and at the mean-while tissue sections were prepared from their kidney and liver. The results
indicate that, the Fe3O4@DMSA–99mTc nanoparticles were passed through the membrane of different cells but do not create any disorder in the kidney and liver
function even in high doses such as 300 mg/kg.