Application Potentials of Microwave in Nano Magnetic Particle Hyperthermia

Cancer hyperthermia is a treatment to increase the tissue temperature to a therapeutic level to kill tumor cells. Over the last three decades, much has been learned about the effects of heat on cells and the interactions between heat and radiation and chemotherapeutic agents [1-2,3-6]. Briefly speaking, by maintaining elevated temperatures (5–10◦C) on tumor cells for several minutes the apoptosis process could be induced. The foremost problem in hyperthermia, however, is the generation and control of heat in tumors. The suitable temperature range of hyperthermia is very small: 42 to 45°C. At lower temperatures, the effect is minimal. At temperatures higher than 45°C, normal cells would be damaged. Due to this narrow temperature range, the response rate of the tumor is highly dependent on how much of it is heated to a therapeutic level. The clinical use of hyperthermia has been restricted by a lack of adequate equipment to effectively deliver heat to deep-seated and even large superficial lesions and by a lack of thermometry techniques that provide reliable information on heat distribution in the target tissues[1, 3-6].Among several techniques for inducing heat, electromagnetic (EM) heating methods are preferable. The main resasons are ease of usage and producing and also controlling the fields. But there are some considerations, the energy deposition is a complex function of the frequency, intensity, and polarization of the applied fields, the applicator’s size and geometry, as well as the size, depth, geometry, and dielectric property of the tumor. The material, thickness, and construction of a cooling bolus also influence the amount of energy deposition.