Surface-modified iron oxide particles for cancer ablation therapy

An object of the present invention is to provide a surface-modified ferromagnetic iron oxide particles suitable for electromagnetic induction cancer cautery treatment is excellent in dispersion stability for injectable medium which has excellent heat-generating properties. Cancers cautery for surface-modified iron oxide particles of the present invention of the solution, the major diameter has 20 to 200 nm, a plate shape ratio of the major axis is 1.5 to 30 with respect to the thickness, the coercive force 30 ～300Oe, saturation magnetization 20~80emu / g, the surface of the ferromagnetic iron oxide particles squareness ratio of the magnetic hysteresis curve having a magnetic property is 0.20 to 0.50, phosphorous polyethylene glycol and side chains to bind the block copolymer of polystyrene having an acid group, characterized by comprising.