A Heat Dissipation Study of Iron Oxide Nanoparticles Embedded an Agar Phantom for the Purpose of Magnetic Fluid Hyperthermia.

Magnetic nanoparticles have recently been the subject of intensive research for biomedical applications. In particular, injecting colloidal magnetic nanoparticles into the cancerous tissues and heating them by heat dissipation from magnetic nanoparticles with applying an alternating magnetic field have been expected as a new cancer treatment (magnetic fluid hyperthermia). In this study, iron oxide nanoparticles were dispersed in an agar phantom in order to use them to mimic tumor tissue that is surrounded by normal tissue. Their heat transfer properties were investigated to study magnetic fluid hyperthermia. Magnetite nanoparticles with a median diameter of 13.8 nm fixed in an agar matrix showed a specific absorption rate of 5.6 W/g in a field of 5.0 kA/m, and a concentration of 5 wt.% was sufficient to increase the temperature above the temperature required for magnetic hyperthermia treatment. The simulated temperature profile inside the phantom shows reasonable agreement with the temperature distribution obtained by experiments. These results offer a guide for preventing the overheating of normal tissues during hyperthermia treatment.