Targeted hyperthermia using dextran magnetite complex: A new treatment modality for liver tumors

Background/Aims : Dextran magnetite complex (DM) is a colloidal suspension of subdomain magnetite particles ('magnetic fluid'). It has been reported that DM generates a great amount of heat in an AC magnetic field. Material and Methods : In this experimental study on Japanese white rabbits, a new treatment modality for liver tumors was examined in which the tumor is selectively heated with an intravascularly administered DM-containing embolic material followed by external application of an AC magnetic field. Results : The heat generation ofDM in vitro was found to be more than 3-fold greater than that with magnetite particles of 40-μm diameter. As a DM-containing embolic material, we developed a DM/Lipiodol® emulsion. When DM/Lipiodol® emulsion was injected into the hepatic arteries of the rabbits following VX2 tumor transplantation into the liver, embolization of the artery and selective heating of the embolized liver were successfully attained following exposure to a 100-kHz AC magnetic field of approximately 15000 A/m. Histological examination of the embolized liver disclosed that DM had accumulated in the hypervascular, viable part of the tumor. Conclusion : These results demonstrate the potential feasibility of using a DM-containing embolic material for targeted hyperthermia of liver tumors.