Development of nano-sized superparamagnetic ferrites having heat generation ability in an AC magnetic field for thermal coagulation therapy

Abstract

Thermal coagulation therapy using powdered magnetic materials in an alternating (AC) magnetic field has been expected as a treatment of cancerous tissues. For nano-sized superparamagnetic particles, the magnetic energy is mainly converted to a heat generation ability by the rotation of the magnetic moment (Néel relaxation) along with the rotation of the particles (Brownian relaxation). Fe3O4 (magnetite) nanoparticles have been mainly investigated as the candidate material for this type of therapy. In this review, an outline of the ferrite materials having heat generation ability in the AC magnetic field is described for the application of the thermal coagulation therapy. In particular, I focused on the preparation of a nano-sized magnetic material using physical bead milling to develop a magnetic material of Y3Fe5O12 and its high heat generation ability. The preparation of Y3Fe5O12 microspheres with a 2032 μm diameter range using the bead-milled powder was also described for the embolization method of cancer treatment. © 2014 The Ceramic Society of Japan. All rights reserved.