Design and Development of a High-Frequency Magnet Prototype for Magnetic Hyperthermia Applications

The objective of this work is to establish a design method of high-frequency magnets for magnetic hyperthermia cancer therapy. For effective induction heating properties of the cancer therapy, the target specifications of the high-frequency magnet system are 0.06 T of the peak magnetic flux density with 200 kHz of the operating frequency at the center of the space. The operating time of the system is required to be 300 seconds. In order to investigate the most optimal design method of high-frequency magnet system for magnetic hyperthermia, this paper demonstrates the design of a small-scale high-frequency magnet prototype based on the magnetic circuit theorem. In the prototype design, ferrite is used as the magnetic core, and copper Litz wires are used for the coil windings. The magnet prototype consists of 8 sets of 10-turns coils. The resulting self-inductance of the prototype was 1.86 mH, and the required operating current to obtain the target magnetic field is estimated to be 46 A in r.m.s. With this design, the voltage across each coil winding becomes 13.4 kV in r.m.s., and 16 sets of 5.45-nF capacitor banks are required for the series resonance circuit. In addition, the Joule heating of coil windings is estimated to be 21.1 kW, which suggests that the magnet cannot be operated without a cooling system.