Use of the Fe–Cr–Nb–B Systems With Low Curie Temperature as Mediators in Magnetic Hyperthermia

Magnetic hyperthermia uses the therapeutic heat given by the magnetic particles (MPs) in the alternating magnetic field for the healing of various cancers. The low Curie temperature particles are intelligent tools for the malignant cell destruction. These magnetic systems are used in the magnetic hyperthermia due to their special magnetic properties as high magnetization and magnetic permeability/susceptibility and low Curie temperature T_c within the range of 42 °C-46 °C. Capability of the Fe-Cr-Nb-B systems to heat uniformly in the hyperthermia range, a complex region with multiple metastases (two spherical metastatic tumors) surrounded by a cubic healthy tissue was the main purpose of this paper. The temperature inside as well as outside the region was computed by finite element method. A significant blood vessel (BV) is located at different distances from tumors. The cooling effect produced by blood flowing in a BV was considered. The presence of the BV induces the thermal gradients within tumors. Their values depend on the tumor-BV distance. The frequency and amplitude of magnetic field and MP concentration are optimized to get the temperature therapeutic range 40 °C-42 °C within tumors as liver, lung, and breast. The heating is automatically stopped when the temperature reaches T_c = 42 °C within tumors. Low particle concentrations inserted in the small injection sites are able to heat the tumor to the therapeutic range.