PURPOSE: A contrast agent is provided to show stability in the body and biocompatibility by iron oxide nanoparticles coated with phosphate-conjugated polymers and to stably contrast all organs, especially lymph nodes which are hard to contrast. CONSTITUTION: A contrast agent contains iron oxide nanoparticles coated with phophate-conjugated polymers. The contrast agent is a superparamagnetic contrast agent. The contrast agent is used as a contrast enhancer of lymph nodes. A method for manufacturing the contrast agent comprises the steps of: conjugating phosphate to the terminal of polymers； and coating iron oxide nanoparticles with the phosphate-conjugated polymers through a ligand substitution.본 발명은 인산염이 결합된 고분자로 코팅된 산화철 나노입자를 포함하는 조영제 및 이의 제조방법에 관한 것이다. 본 발명의 인산염이 결합된 고분자로 코팅된 산화철 나노입자는 체내 안정성 및 생체 적합성이 뛰어나며, 안정적으로 모든 장기를 조영할 수 있으며, 특히 그동안 조영이 매우 어려웠던 림프절까지 조영할 수 있다.
