Towards optimal thermal distribution in magnetic hyperthermia

TL;DR

This paper proposes an optimal heat source distribution for magnetic hyperthermia, demonstrating improved temperature control and SAR values using nanocapsule assemblies with optimized size and structure.

Contribution

It introduces a linear combination of spherical heat sources for optimal thermal distribution and optimizes nanocapsule design to enhance SAR in magnetic hyperthermia.

Findings

Optimal spherical heat source distribution achieves better temperature control.

Nanocapsule assemblies can reach SAR of 250-400 W/g at moderate field conditions.

Optimized capsule design reduces magneto-dipole interactions.

Abstract

A linear combination of spherically symmetric heat sources is shown to provide optimal stationary thermal distribution in magnetic hyperthermia. Furthermore, such spatial location of heat sources produces suitable temperature distribution in biological medium even for assemblies of magnetic nanoparticles with a moderate value of specific absorption rate (SAR), of the order of 100 - 150 W/g. We also demonstrate the advantage of using assemblies of magnetic nanocapsules consisting of metallic iron nanoparticles covered with non magnetic shells of sufficient thickness in magnetic hyperthermia. Based on numerical simulation we optimize the size and geometric structure of biocompatible capsules in order to minimize the influence of strong magneto-dipole interaction between closely spaced nanoparticles. It is shown that assembly of capsules can provide sufficiently high SAR values of the order of 250 - 400 W/g at moderate amplitudes H = 50 - 100 Oe and frequencies f = 100 - 200 kHz of alternating magnetic field, being appropriate for application in clinics