Analysis of heat generation through electromagnetic energy conversion for magnetic hyperthermia cancer treatment

Hyperthermia (HT) is a cancer treatment that utilizes a variety of heating methods to destroy cancerous tumors. A diversity of technical problems still exists regarding HT's different approaches, therapeutic potential, and evidence of effectiveness. The foremost problem is in generating and controlling heat in tumors to target cancer sites. The window of temperature for HT is between 42°C and 45°C, with the literature suggesting 43°C to be the ideal temperature for inducing apoptosis (programmed cell death). Normal cells undergo necrosis at higher temperatures than that of the specified range. To address control problems, various methods have been utilized to localize HT heating and limit its temperatures through various applicators, materials, and procedures. One method has been to implant various materials into the human body to heat tumors, a process known as Magnetic Hyperthermia (MH) as it uses magnetic nanoparticles (NP). This method is particularly useful for sending thermal energy to deep seated tumors by using ferro/ferri magnetic NP that absorb non-ionizing electromagnetic (EM) fields delivered into the human body externally. These NP have been shown to heat surrounding tissue until they reach a Curie temperature (T_c) at which generated heat is minimized (many thermodynamic properties change at T_c, such as dielectric, elastic, optical and thermal properties. Fabricated NP, due to spontaneous polarization, can heat via hysteresis losses under applied EM fields making them candidates for testing in (EM) HT systems. Various ferro- and ferromagnetic materials have been studied extensively by this group (e.g.: Ni-Cu, Ni-Co, Ni-Cr, Er, Ce, Gd, and their alloys, etc.) as candidates for HT due to their production of heat through hysteresis or magnetic spin mechanisms. With the use of these nanoparticle systems, the focus of this paper is to produce analysis of heat generation through electromagnetic energy conversion for magnetic hyperthermia cancer treatment and to investigate the heat transfer and heat generation of magnetic NP due to temperature rise upon application of externally applied AC magnetic field. Both, polarization switching and inhomogenities affect polarization orientation within a crystal. Domain switching occurs in two steps: first, the domain nucleates at critical level of applied EM field; second, the interface between the two domains propagates. Particles moving across the interface transform from one domain type to another, which leads to a release of energy in the form of heat. This, in turn, leads to a temperature rise at the interface.