Induction Heating of Magnetic Fluids for Hyperthermia Treatment

The induction heating of magnetic fluids for magnetic induction hyperthermia treatments is theoretically analyzed, with regard to the influences by magnetic field parameters, material properties, and demagnetizing field effects in finite-size samples. A monodispersion model of noninteracting superparamagnetic particles, subjected to a magnetic field of the intensity h_ex < 16 kAm^-1 and frequency f < 1 MHz, is used for the analysis. Calculation results show that the induction heating has a quasi-linear dependence on field intensity and a quasi-negative exponential dependence on field frequency. As for the influences by material parameters, respectively, the induction heating has a double-exponential-like dependence on the magnetic core size and a negative dependence on the coating layer thickness of the superparamagnetic particles. Similarly, the heating dependence on the carrier liquid viscosity is also a double-exponential-like relationship. Besides, the induction heating has a linear dependence on the volume fraction of the superparamagnetic particles, and a negative dependence on the demagnetizing factors, which are related to the sample shapes and orientations. Initial experiments are performed for validating the analytical calculation results.