Development of Cancer Treatment System by Induction Heating

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-Device developmentIn order to extend the maximum range for cancer treatment, we have improved the first prototype device (which could generate the magnetic field of 3 mT at 40 mm from the induction coil). By increasing the output power to 10kW, the resonance current to 300 A, and the coil diameter to 30 cm, we have been able to realize 3 mT at about 90 mm, which was confirmed by the actual measurement of induced magnetic field strength from the improved device.-Highly effective applicator(a)Use of a high magnetic permeability material (ferrite)The range of the treatment has been further extended to 120 mm, by placing a ferrite board under the coil. From an electromagnetic simulation, we have also confirmed that this ferrite board reduces the electromagnetic waves leaking from the applicator.(b)Use of "litz wire" with low "high-frequency resistance"The copper loss of the applicator on a previous device was as high as 5 kW, because of the high "high-frequency resistance" of the coil wir … More es. Making use of the low "high-frequency resistance" of "litz wire," we have reduced the power consumption of the device by approximately 30%.-DM heating mechanismsIn order to clarify the heating mechanism of Dextran Magnetite (DM), we have measured its "hysteresis loss" by filling the DM solution into a toroidal tube. As a result, we have found that the hysteresis loss occupies about 40 percent of the total amount of DM heating.-Simulation of cooling blood flowThe cooling mechanism of the heated regions due to the blood flow has been examined by a one-dimensional heat conduction simulation.-Eddy current reductionIn the tests using large animals such as pigs, it is necessary to reduce the "eddy current heating" on normal cells. By assuming a simple model, we have found theoretically that the eddy current heating can be reduced even when the DM is sufficiently heated, by adjusting the output frequency of the device as approximately 150 kHz.-Other EMC measurement techniques have been developed associated with the induction heating. Less