In this article, we discuss numerical aspects related to the accuracy and computational efficiency of dosimetric simulations, performed in context human exposure static inductive charging systems electric vehicles. Two alternative methods based on vector potential scalar formulations, respectively, are here considered for field computation highly detailed anatomical models. The results obtained by implementation both approaches discussed terms compliance assessment with ICNIRP guidelines...

Purpose To investigate how the simultaneous exposure to gradient and RF fields affects temperature rise in patients with a metallic hip prosthesis during an MRI session. Methods In silico analysis was performed anatomically realistic human model CoCrMo implant 12 imaging positions. The at 1.5 T 3 T, considering four clinical sequences: turbo spin‐echo, EPI, gradient‐echo, true fast sequence steady precession. evaluated separately superposed, by adopting ad hoc computational algorithm....

To theoretically investigate the feasibility of a novel procedure for testing MRI gradient-induced heating medical devices and translating results into clinical practice.

Magnetic resonance imaging scanners can provide, by B1-mapping techniques, measurements of the transmit sensitivity magnitude, whereas phase only be approximated under symmetry assumptions coil and sample. Nonetheless, up to now many techniques have been proposed retrieve electric properties maps at radiofrequency elaborating complex sensitivity. These are usually referred as magnetic resonance-based tomography. In order perform elecric also in cases which do not fulfill for estimation, a...

Patients with implanted orthopaedic devices represent a growing number of subjects undergoing magnetic resonance imaging (MRI) scans each year. MRI safety labelling is required for all implants under the EU Medical Device Regulations to ensure regulatory compliance, device assessed through standardised testing procedures. In this paper, we employ parametric studies assess range clinically relevant factors that cause tissue heating, performing simulations both radiofrequency (RF) and gradient...

Abstract Objective. Numerical simulations are largely adopted to estimate dosimetric quantities, e.g. specific absorption rate (SAR) and temperature increase, in tissues assess the patient exposure radiofrequency (RF) field generated during magnetic resonance imaging (MRI). Simulations rely on reference anatomical human models tabulated data of electromagnetic thermal properties biological tissues. However, concerns may arise about applicability computed results any phenotype, introducing a...

A computational procedure, based on the boundary element method, has been developed in order to evaluate electric field induced a body that moves static around an MRI system. general approach enables us investigate rigid translational and rotational movements with any change of motion velocity. The accuracy computations is validated by comparison analytical solutions for simple shaped geometries. Some examples application proposed procedure case scanner are finally presented.

This paper focuses on the estimation of Specific Absorption Rate (SAR) and temperature increase within an irradiated human body, starting from known values electric magnetic fields around body. The proposed approach, based Boundary Element Method (BEM) for solution integrated electromagnetic/thermal problem, uses SAR provided by electromagnetic as input bioheat equation which includes effects metabolic heat blood flow. validity BEM approach is proved in analysis a simplified model comparison...

A hybrid finite element-boundary element method, developed to solve eddy-current problems in the frequency domain, is applied electromagnetic analysis of voxel-based human models. specific procedure employs a massively parallelized algorithm implemented on multiple Graphic Processing Units (GPU) code speed up solution large systems whose matrix exceeds RAM capability. The database structure used for problem also suitable successive thermal evaluate distribution temperature elevation due...

The paper presents a computational study for the estimation of temperature elevation occurring in human subject carrying metallic hip prostheses when exposed to magnetic field produced by gradient coils.The simulations are performed through validated numerical codes, which solve electromagnetic and thermal equations applied high-resolution anatomical model. Three different sets coils (traditional, split uniplanar) considered evaluate maximum steady-state body. This result is then rescaled...

This paper presents an extended comparison between numerical simulations using the different computational tools employed nowadays in electromagnetic dosimetry and measurements of radiofrequency (RF) field distributions phantoms with tissue-simulating liquids at 64 MHz, 128 MHz 300 adopting a customized experimental setup. The aim is to quantify overall reliability accuracy RF approaches frequencies use magnetic resonance imaging transmit coils.

The availability of adapted phantoms mimicking different body parts is fundamental to establishing the stability and reliability magnetic resonance imaging (MRI) methods. primary purpose such physiologically relevant, contrast-creating relaxation times T1 T2. For head, frequently examined by MRI, an anthropomorphic design brain would imply discrimination gray matter white (WM) within defined, spatially distributed compartments. Multichannel extrusion printing allows layer-by-layer...

Objective.To quantify the effects of different levels realism in description anatomy around hip, knee or shoulder implants when simulating, numerically, radiofrequency and gradient-induced heating magnetic resonance imaging. This quantification is needed to define how precise digital human model modified with implant should be get realistic dosimetric assessments.Approach. The analysis based on a large number numerical simulations where four 'levels realism' have been adopted modelling...

Contrast source inversion electric properties tomography (CSI-EPT) is a recently developed technique for the that recovers distribution starting from measurements performed by magnetic resonance imaging scanners. This method an optimal control approach based on contrast technique, which distinguishes itself other techniques its capability to recover also local specific absorption rate distribution, essential online dosimetry. Up now, CSI-EPT has only been described in terms of integral...

Abstract This work focuses on the in silico evaluation of energy deposed by MRI switched gradient fields bulk metallic implants and consequent temperature increase surrounding tissues. An original computational strategy, based subdivision coil switching sequences into sub-signals time-harmonic electromagnetic field solution, allows to realistically simulate evolution phenomena produced coils fed according any sequence. Then, Pennes’ bioheat equation is solved through a Douglas–Gunn time...

We investigated the efficiency in magnetic field mitigation of superimposed MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Fe coaxial cups with cylindrical symmetry, subjected to an applied parallel their axis. The cup was grown by a microwave-assisted Mg-liquid infiltration technique boron preform. This allows obtaining samples reduced amount unreacted magnesium, shape chosen before growth procedure, and easily scalable sizes....

This paper aims at investigating the exposure experienced by nursing staff executing transcranial magnetic stimulations (TMSs) and proposing a shielding system composed of an aluminum half cylinder placed around coil. The analysis is carried out through finite-element approach, using Duke (Virtual Family) anatomical model to represent operator body. TMS apparatus, spiral circular coil supplied short-duration sinusoidal current ~6 kA, has been analyzed with without shield. 60 relative...

Purpose: Bearing partially or fully metallic passive implants represents an exclusion criterion for patients undergoing a magnetic hyperthermia procedure, but there are no specific studies backing this restrictive decision. This work assesses how the secondary field generated at surface of two common types prostheses affects safety and efficiency treatments localized tumors. The paper also proposes combination multi-criteria decision analysis graphical representation calculated data as...

Due to the large variety of possible clinical scenarios, a reliable heating-risk assessment is not straightforward when patients with arthroplasty undergo MRI scans. This paper proposes simple procedure estimate thermal effects induced in hip, knee, or shoulder during exams. The most representative scenarios were identified by preliminary frequency analysis, based on service databases, collecting exams 11,658 implant carrier patients. produced radiofrequency and switching gradient fields...

Purpose The goal of this study was to conduct an exposure assessment for workers moving through the stray stationary field common MRI scanners, performed according recent International Commission on Non‐Ionizing Radiation Protection (ICNIRP) Guidelines, which aim at avoiding annoying sensory effects. Theory and Methods analysis numerical simulations, using a high‐resolution anatomical model that moved along realistic trajectories in proximity tubular open scanner. Both dosimetric indexes...