Effect of Functional Magnetic Particles on Radiofrequency Capacitive Heating: An in vivo Study

Specific heating of magnetic particles in radiofrequency (RF) capacitive hyperthermia and its hyper‐thermic effect were investigated in an in vivo study. Magnetite cationic liposomes (MCLs) were injected into a rat tumor on the femur and 8 MHz‐RF capacitive heating was applied to the rat under‘mild heating’ conditions. Although the input power of RF capacitive heating was low under the same power conditions, the MCLs‐injected tumor was heated over 43°C, whereas it was only heated to 41°C in the case of the rats not injected with MCLs. A necrotic area in the tumor was observed in the heated rats. From the results of histological observation of the removed tissue, the necrotic area in the MCLs‐injected tumor was wider than that in MCLs‐free tumor. Complete tumor suppression was observed in 71% (5/7) of MCLs‐injected rats, and the hyperthermic effect was greatly improved by the MCLs.