H-Field Contribution to the Electromagnetic Energy Deposition in Tissues Similar to the Brain but Containing Ferrimagnetic Particles, During Use of Face-Held Radio Transceivers

Abstract

Abstract-A portable radio transceiver with rubber ducky antenna emitting at 446 MHz with an output power of 5 W was considered as near-field source of electric (E) and magnetic (H) field components when being used in the proximity of the user's face. By taking into account the significant content of ferrimagnetic nanoparticles recently identified to reside in the human brain, we assessed the specific absorption rate (SAR) of energy deposition due to H-component penetrating a presumptive forebrain. H-component SAR contribution to the total SAR is for the first time estimated in such a case, based on an original idea inspired from knowledge on magnetic fluids hyperthermia.

Exposimetric Characterization of the Near-Field of a Portable Transceiver Emitting in the Ultrahigh Frequency Range and Simulation of the Electromagnetic Power Deposited in a Ferrimagnetic Biological Tissue Present in Such a Field

“…Both measurements of E-and H-fields took place in a usual room, and one notes that a good symmetry of field distribution over 360 degrees around the transceiver was obtained. In Figure 6 it is emphasized the volume loss density distribution in the modelled For current calculations we used a brain model of volume=1130 cm 3 (and dielectric properties of human brain tissue) containing five spheres of magnetite (with electric and magnetic properties taken at 440 MHz [5]) with radius=1 cm and a monopole antenna with input power=1 W and a computed η=92.6 %. In this case we obtained a mean SAR=0.055W/kg in the brain, which is 3.1% less than the mean SAR computed based only on E-field absorption considerations.…”

“…Identifying a possible hazardous situation in this way, we were further interested to analyze the exposure to ultrahigh frequency (UHF) radiation in connection to a neglected aspect: magnetite nanoparticles, which are ferrimagnetic, are present in the brain and could absorb the H-field component in a consistent manner [4]. Therefore we aimed to quantify the order of magnitude at which an UHF H-field absorption takes place in ferrimagnetic fluids when they are exposed in the very proximity of a portable transceiver [5]. We have split the SAR evaluation problem in two: power loss assessment due to pure dielectric heating of tissues and power loss assessment due to magnetic heating of tissues when they contain ferro-or ferrimagnetic particles.…”

Magnetite Particle Presence in the Human Brain: A Computational Dosimetric Study to Emphasize the Need of a Complete Assessment of the Electromagnetic Power Deposition at 3.5 GHz

“…Magnetic nanoparticles in human tissues, and more specifically in the brain, have been scarcely investigated for their electromagnetic wave absorption at Ultra-High Frequencies (UHF) [1,2]. The presence of biogenic magnetite (Fe 3 O 4 ) nanocrystals in the human brain was discovered in 1992, while the concentration of 0.2-12µg magnetite in each 1g of dry cerebral tissue was identified in 2009 [3].…”

Simulation Research on Magnetoacoustic Concentration Tomography With Magnetic Induction Based on Uniaxial Anisotropy of Magnetic Nanoparticles

“…However, due to contributions such as magnetocrystalline, shape, and surface, MNPs exhibited anisotropy, and the anisotropy displayed a first order-dominant uniaxial characteristic [21]. The magnetization of MNPs was affected by many factors [22][23][24][25][26], among which the uniaxial anisotropy of MNPs directly led to the change of the static magnetization curve [27]. In the numerical calculation, magnetic force, acoustic source, and acoustic pressure were all solved based on the static magnetization curve.…”