Influence of Anisotropic White Matter on Magnetic and Electric Field Distribution of a Realistic Head Model

2009 ◽  
Author(s):  
Dan-dan Yan ◽  
Jian-wei Zhang ◽  
Jing Li
Keyword(s):  
White Matter ◽  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Head Model ◽  
Realistic Head Model

scholarly journals Calculation of electromagnetic field from mobile phone induced in the pituitary gland of children head model

2017 ◽  
Vol 74 (9) ◽  
pp. 854-861 ◽  
Author(s):  
Vladimir Stankovic ◽  
Dejan Jovanovic ◽  
Dejan Krstic ◽  
Vera Markovic ◽  
Momir Dunjic
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Pituitary Gland ◽  
Mobile Phone ◽  
Penetration Depth ◽  
Field Distribution ◽  
Mobile Communications ◽  
Electric Field Distribution ◽  
Head Model ◽  
Exposure Limits

Background/Aim. A mobile phone is a source of electromagnetic radiation located close to the head and consequently its intense use may cause harmful effects particularly in younger population. The aim of this study was to investigate the influence of electromagnetic field of the mobile phone on the pituitary gland of the child. Methods. In order to obtain the more accurate results for this research 3D realistic model of child's head whose size corresponds to an average child (7 years old) was created. Electric field distribution in child head model and values of Specific Absorption Rate (SAR) at the region of pituitary gland were determined. This study was performed for the frequencies of 900 MHz, 1800 MHz, and 2100 MHz, as the most commonly used in mobile communications. The special attention was dedicated to the values of the electric field and the values of the SAR in the pituitary gland. For all frequencies over 10 g and 1 g of tissue average SAR was calculated. The electric field distribution and values of average SAR for 10 g and 1 g trough the model of child's head were obtained by the using numerical calculation based on the Finite Integration Technique (FIT). Results. The largest value of electric field in the region of the pituitary gland was at the frequency of 900 MHz, as a consequence of the highest penetration depth. Lower values of the electric field in the region of the pituitary gland were at frequencies of 1,800 MHz and 2,100 MHz. The SAR in the pituitary gland decreased as the frequency increased as a direct consequence of lower penetration depth. Conclusion. The electric field strength from a mobile phone is higher than the value specified by standards for the maximum allowable exposure limits. The high values of the electric field are not only in the vicinity of a mobile phone but also in tissues and organs of the human head. Particular attention should be paid to the exposure of children to radiation of mobile phones. Smaller dimensions of children?s head and smaller thickness of tissues and organs have as a consequence greater penetration of electromagnetic waves.

scholarly journals A computational pipeline to determine lobular electric field distribution during cerebellar transcranial direct current stimulation

2019 ◽  
Author(s):  
Zeynab Rezaee ◽  
Anirban Dutta
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Field Distribution ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Electric Field Distribution ◽  
Head Model ◽  
Computational Pipeline ◽  
Model Interaction ◽  
Subject Specific

AbstractObjectiveCerebellar transcranial direct current stimulation (ctDCS) is challenging due to the complexity of the cerebellar structure. Therefore, our objective is to develop a freely available computational pipeline to perform cerebellar atlas-based electric field analysis using magnetic resonance imaging (MRI) guided subject-specific head modeling.MethodsWe present a freely available computational pipeline to determine subject-specific lobular electric field distribution during ctDCS. The computational pipeline can isolate subject-specific cerebellar lobules based on a spatially unbiased atlas (SUIT) for the cerebellum, and then calculates the lobular electric field distribution during ctDCS. The computational pipeline was tested in a case study using a subject-specific head model as well as using a Colin 27 Average Brain. The 5cmx5cm anode was placed 3 cm lateral to inion, and the same sized cathode was placed on the contralateral supraorbital area (called Manto montage) and buccinators muscle (called Celnik montage). A 4×1 HD-ctDCS electrode montage was also implemented for a comparison using analysis of variance (ANOVA).ResultsEta-squared effect size after three-way ANOVA for electric field strength was 0.05 for lobule, 0.00 for montage, 0.04 for head model, 0.01 for lobule*montage interaction, 0.01 for lobule* head model interaction, and 0.00 for montage*head model interaction in case of Enorm. Here, the electric field strength of both the Celnik and the Manto montages affected the lobules Crus II, VIIb, VIII, IX of the targeted cerebellar hemispheres while Manto montage had more bilateral effect. The HD-ctDCS montage primarily affected the lobules Crus I, Crus II, VIIb of the targeted cerebellar hemisphere. Our freely available computational modeling approach to analyze subject-specific lobular electric field distribution during ctDCS provided an insight into healthy human anodal ctDCS results

Modelling of the electric field distribution in the brain during tDCS

2016 ◽  
Vol 31 (5) ◽  
Author(s):  
Alexander V. Ashikhmin ◽  
Rubin R. Aliev
Keyword(s):  
Spatial Distribution ◽  
Electric Field ◽  
Field Distribution ◽  
Direct Current ◽  
Electric Field Distribution ◽  
Human Head ◽  
Head Model ◽  
Electrode Size ◽  
Common Electrode ◽  
The Brain

AbstractWe simulated the electric current distribution in the brain during transcranial direct current stimulation (tDCS) using an anatomically accurate human head model. We estimated an effect of common electrode montages on spatial distribution of the electric field during tDCS procedure and analyzed a sensitivity of the technique to variations of electrode size and orientation. We concluded that the used electrode montages are stable with respect to minor changes in electrode size and position, while an assumption of homogeneity and isotropy of the head model results in crucial changes of the electric field distribution. We determined the electrode montages suited to deliver strong effect on hippocampus and cerebellum.

scholarly journals Direct-Current Electric Field Distribution in the Brain for Tumor Treating Field Applications: A Simulation Study

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Yung-Shin Sun
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Fields ◽  
Direct Current ◽  
Electric Field Distribution ◽  
Total Power ◽  
Head Model ◽  
Direct Current Electric Field ◽  
The Brain ◽  
Current Electric Field

Tumor Treating Fields (TTFields) in combination with chemotherapy and/or radiotherapy have been clinically reported to provide prolonged overall survival in glioblastoma patients. Alternating electric fields with frequencies of 100~300 kHz and magnitudes of 1~3 V/cm are shown to suppress the growth of cancer cells via interactions with polar molecules within dividing cells. Since it is difficult to directly measure the electric fields inside the brain, simulation models of the human head provide a useful tool for predicting the electric field distribution. In the present study, a three-dimensional finite element head model consisting of the scalp, the skull, the dura, the cerebrospinal fluid, and the brain was built to study the electric field distribution under various applied potentials and electrode configurations. For simplicity, a direct-current electric field was used in the simulation. The total power dissipation and temperature elevation due to Joule heating in different head tissues were also evaluated. Based on the results, some guidelines are obtained in designing the electrode configuration for personalized glioblastoma electrotherapy.

Effect of Void Shape in Polymeric Insulator on the Electric Field Distribution

2017 ◽  
Vol 5 (3) ◽  
pp. 96
Author(s):  
I. Made Yulistya Negara ◽  
Dimas Anton Asfani ◽  
Daniar Fahmi ◽  
Yusrizal Afif
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Void Shape

Tuning the Localized Surface Plasmon Resonance of Al-Al2O3 Nanosphere Towards NIR Region by Gold Coating

2020 ◽  
Vol 12 ◽  
Author(s):  
Jyoti Katyal ◽  
Shivani Gautam
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Dielectric Layer ◽  
Electric Field Distribution ◽  
Active Material ◽  
Visible Region ◽  
Field Enhancement ◽  
Localized Surface Plasmon ◽  
Sers Substrate ◽  
Al Nanoparticles

Background: A relatively narrow LSPR peak and a strong inter band transition ranging around 800 nm makes Al strongly plasmonic active material. Usually, Al nanoparticles are preferred for UV-plasmonic as the SPR of small size Al nanoparticles locates in deep UV-UV region of the optical spectrum. This paper focused on tuning the LSPR of Al nanostructure towards infrared region by coating Au layer. The proposed structure has Au as outer layer which prevent the further oxidation of Al nanostructure. Methods: The Finite Difference Time Domain (FDTD) and Plasmon Hybridization Theory has been used to evaluated the LSPR and field enhancement of single and dimer Al-Al2O3-Au MDM nanostructure. Results: It is observed that the resonance mode show dependence on the thickness of Al2O3 layer and also on the composition of nanostructure. The Au layered MDM nanostructure shows two peak of equal intensities simultaneously in UV and visible region tuned to NIR region. The extinction spectra and electric field distribution profiles of dimer nanoparticles are compared with monomer to reveal the extent of coupling. The dimer configuration shows higher field enhancement ~107 at 1049 nm. By optimizing the thickness of dielectric layer the MDM nanostructure can be used over UV-visible-NIR region. Conclusion: The LSPR peak shows dependence on the thickness of dielectric layer and also on the composition of nanostructure. It has been observed that optimization of size and thickness of dielectric layer can provide two peaks of equal intensities in UV and Visible region which is advantageous for many applications. The electric field distribution profiles of dimer MDM nanostructure enhanced the field by ~107 in visible and NIR region shows its potential towards SERS substrate. The results of this study will provide valuable information for the optimization of LSPR of Al-Al2O3-Au MDM nanostructure to have high field enhancement.

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