Numerical investigation of temperature field in magnetic hyperthermia considering mass transfer and diffusion in interstitial tissue

Abstract

Magnetic nanoparticle (MNP) hyperthermia ablates malignant cells by heating the region of interest when MNPs are subjected to an external alternating magnetic field. The energy density to be dissipated into heat, and consequently the temperature profile during treatment, depends on the distribution of MNPs within the tumoral region. This paper uses numerical models to evaluate the temporal and spatial temperature distributions inside a tumor when intratumoral injection of MNPs is considered. To this end, the theories of mass transfer and diffusion in interstitial tissue are combined with Rosensweig’s theory and Pennes bio-heat transfer equation, and the finite element method is used for analyzing the temperature field under different scenarios. Simulation results demonstrate that the treatment temperature field strongly depends on factors, such as the injection method, particle size, injection concentration and injection dose. However, the maximal temperature reached during hyperthermia and the effective treatment area are difficult to control. In order to obtain better treatment effects, this paper investigates a solution that uses a kind of material with low Curie temperature and the results show that the effective treatment area of hyperthermia can be significantly improved using this type of MNP.

Multiscale Modelling of Nanoparticle Distribution in a Realistic Tumour Geometry Following Local Injection

“…For positively charged particles the increase in deposition is great enough to restrict the concentration profile of nanoparticles within the fluid further despite the increase in diffusivity of the particles. Sometimes one of these transport mechanisms can be left out when simulating for nanoparticle concentration during intra-tumoural injection [ 12 , 44 , 45 ], however, these results demonstrate how each contributes significantly to the final distribution of nanoparticles and so the importance of including all three. In comparison with our previous work the inclusion of a realistic tumour geometry and measured particle values increase the realism of the model and its usability in conjunction with future clinical trials.…”

“…This is due to the rate of deposition for particles with different surface charges-for negatively charged particles the rate of deposition is low therefore fewer particles will deposit close to the injection location allowing more to penetrate further into the tumour. In this field the distance from the injection site the particles reach is the main result of concern [ 12 , 21 , 23 , 45 ], as most particles injected have a short range of effect. For the particles to significantly aid cancer treatment a uniform spread of particles throughout the tumour is desired, as to leave an area untouched only increases the risk of the treatment not working and the cancer returning.…”

Thermo-fluid porosity-related effects in the magnetic hyperthermia

“…And d p 10 −4 m the mean diameter of the cell tissue. The ferrofluid velocity within a porous tissue is the solution of the equation [12]:…”

“…Table 1 The simulation parameters' values [7,12] Characteristics Tumor tissue (i 1) Healthy tissue (i 2)…”

“…The thermal and magnetic characteristics[4,7,12] Boltzmann constant. The effective relaxation time τ contains the Brown relaxation time τ B and Néel relaxation time τ N :…”