Controlling temperature in magnetic hyperthermia with low Curie temperature particles

Abstract

Hyperthermia induced by the heating of magnetic particles (MPs) in alternating magnetic field receives a considerable attention in cancer therapy. An interesting development in the studies dedicated to magnetically based hyperthermia is the possibility to control the temperature using MPs with selective magnetic absorption properties. This paper analyzes the temperature field determined by the heating of MPs having low Curie temperature (a FeCrNbB particulate system) injected within a malignant tissue, subjected to an ac magnetic field. The temperature evolution within healthy and tumor tissues was analyzed by finite element method simulations in a thermo-fluid model. The cooling effect produced by blood flowing in blood vessels was considered. This effect is intensified at the increase of blood velocity. The FeCrNbB particles, having the Curie temperature close to the therapeutic range, transfer the heat more homogeneous in the tumor keeping the temperature within the therapeutic range in whole tumor volume. Having the possibility to automatically control the temperature within a tumor, these particle type opens new research horizons in the magnetic hyperthermia.

Novel nanoparticles with Cr3+ substituted ferrite for self-regulating temperature hyperthermia

“…Since normal cells possess higher heat resistance and resilience than tumor cells, the tumor cells can be killed without affecting normal tissue if the temperature can be maintained accurately to within 42 o C-45 o C. [5][6][7] As monitoring hyperthermia temperature in vivo with minimal invasion is still a challenge, magnetic media with low Curie temperature, in particular at the hyperthermia temperature range of 42-45 o C, are highly desired. [8][9][10][11][12] The Curie temperature is the temperature at which ferromagnetic materials lose their intrinsic permanent magnetic properties and consequently lose their ability of aligning to external fields and thus facilitating the conversion of external electromagnetic energy into highly localized heat. The Curie temperature therefore gives an upper limit to the operational temperature for the magnetic media.…”

A temperature analysis in magnetic hyperthermia

“…The space-time temperature distribution within malignant and healthy tissues is described by the solution: T i =T i x,y,z,t , i=1, 2 of the bioheat transfer equation in the living tissues [5,7]:…”

“…The malignant cells are destroyed due to their small thermal resistance, when the temperature of the tissue reaches the therapeutic temperature range 42 -46 o C [1,2,3]. Efficiency of this therapy is increased if the following requirements are applied: i) the best magnetic materials with special magnetic characteristics (magnetization, anisotropy), ii) the suitable values of the magnetic field parameters which determines a hyperthermic temperature field within tissues and iii) the optimum clinical dosage of the particles [4,5,6]. In the controlled burning processes of the malignant tissues, the clinic dosage is strongly influenced if the particles are distributed within tumor volume.…”

Thermofluid Analysis in Magnetic Hyperthermia Using Low Curie Temperature Particles

“…These particles convert the magnetic energy received from magnetic field to thermal energy and transfer it into tumor tissue determining a focused temperature rise. The malignant tissues are destroyed when the temperature values are within the therapeutic range: 40 -44 o C [2,3,4]. The heating effects depend strongly on the magnetic and thermal properties of the MPs.…”