Mössbauer spectroscopy and proton relaxometry study of magnetite nanoparticles designed for preparing diagnostic contrast media

Mössbauer spectroscopy, proton relaxometry, and transmission electron microscopy are used to study magnetite nanoparticles designed for creating diagnostic contrast media. Superparamagnetic magnetite nanoparticles with a size of 5–7 nm and blocking temperature of T b = 50 K are examined as a component of diagnostic contrast media with relaxation times T 1 and T 2 capable of circulating in the bloodstream for a long time. Larger ferrimagnetic nanoparticles (30–40 nm) can be concentrated in pathological tissues by applying an external magnetic field, thereby providing a means for hyperthermia.