the present invention is self-containing iron oxide nanoparticles coated with iron oxide nanoparticles The magnetic improved by heat treatment using a salt of a hydrophilic material which is produced by the method of biocompatible oxide nanoparticles and thus resonance imaging (magnetic resonance imaging, MRI) relates to a contrast agent. Among hydrophilic substances carboxymethyl dextran (Carboxymethyl dextran, CM-dextran) is most efficient to achieve the stabilization of the heat-treated iron oxide nanoparticles and further contrast effect.본 발명은 염을 이용한 열처리로 자성이 향상된 산화철 나노입자를 친수성 물질로 코팅하여 생체적합성 산화철 나노입자의 제조방법 및 이에 의해 제조되는 산화철 나노입자를 포함하는 자기공명영상(magnetic resonance imaging, MRI) 조영제에 관한 것이다. 친수성 물질 중에서 카르복시메틸 덱스트란(Carboxymethyl dextran, CM-dextran)이 열처리된 산화철 나노입자를 안정화시키고 나아가 조영효과를 발휘하는데 가장 효율적이다.
