A multifrequency eletromagnetic applicator with an integrated AC magnetometer for magnetic hyperthermia experiments

Abstract

In the present paper, a lab-made electromagnetic applicator for magnetic hy- perthermia experiments is described, fabricated and tested. The proposed device is able to measure the speci c absorption rate (SAR) of nanoparticle samples at di erent magnetic eld intensities and frequencies. Based on a variable parallel LCC resonant circuit fed by a linear power ampli er, the electromagnetic applica- tor is optimized to generate a controllable and homogeneous AC magnetic eld in a 3.5 cm3 cylindrical volume, in a wide frequency range of 149 to 1030 kHz with high eld intensities (up to 35 kA m-1 at low frequencies and up to 22 kA m-1 at high frequencies). In addition, a lab-made AC magnetometer is integrated in the electromagnetic applicator. The AC magnetometer is fully compensated to provide accurate measurements of the dynamic hysteresis cycle for nanoparticle powders or dispersions. From these dynamic hysteresis loops the SAR of the nanoparticle samples can be directly obtained. To show the capabilities of the proposed setup, the AC hysteresis loops of two di erent magnetite nanoparticle samples with dif- ferent sizes have been measured for various eld intensities and frequencies. To our knowledge, no other work reports an electromagnetic applicator system with integrated AC magnetometer providing such characteristics in terms of frequency and intensity.