Design and analysis of novel focused hyperthermia devices

Magnetic fluid hyperthermia (MFH) is a promising cancer therapy by virtue of its good depth penetration. As the injected magnetic fluids of MFH are inevitably distributed in the tumor as well as in normal tissues nearby, it is difficult to accurately heat and ablate the targeted tumor without damaging the surrounding healthy tissues. Based on the observation that magnetic nanoparticles are only heated by alternating fields and not by static dc fields, it is possible to exploit such findings in MFH therapy to provide an efficient cure for cancer patients. To avoid unnecessary heating of healthy tissues, a novel system is proposed to set up a dc magnetic field around the tumor target. At the same time, the system creates a field-free region (FFR) with negligible static magnetic field in the target area. The target area can then be fully heated by an alternating field whereas the nearby tissues are not heated. In this paper, a novel ac and dc magnetic field combined MFH system, targeting the treatment area, is presented to produce an accurately focused magnetic field to abate the tumor cells. The proposed method is validated using finite element analysis.