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.

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

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 Predicting the electric field distribution in the brain for the treatment of glioblastoma

2014 ◽  
Vol 59 (15) ◽  
pp. 4137-4147 ◽  
Author(s):  
Pedro C Miranda ◽  
Abeye Mekonnen ◽  
Ricardo Salvador ◽  
Peter J Basser
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
The Brain

scholarly journals Individual head models for estimating the TMS-induced electric field in rat brain

2019 ◽  
Author(s):  
Lari M. Koponen ◽  
Matti Stenroos ◽  
Jaakko O. Nieminen ◽  
Kimmo Jokivarsi ◽  
Olli Gröhn ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Magnetic Stimulation ◽  
Cortical Activation ◽  
Head Model ◽  
Spherically Symmetric ◽  
Simple Method ◽  
X Ray ◽  
Conductivity Profile ◽  
The Brain

AbstractIn transcranial magnetic stimulation (TMS), the initial cortical activation due to stimulation is determined by the state of the brain and the magnitude, waveform, and direction of the induced electric field (E-field) in the cortex. The E-field distribution depends on the conductivity geometry of the head. The effects of deviations from a spherically symmetric conductivity profile have been studied in detail in humans. In small mammals, such as rats, these effects are more pronounced due to their smaller and less spherical heads. In this study, we describe a simple method for building individual realistically shaped head models for rats from high-resolution X-ray tomography images. We computed the TMS-induced E-field with the boundary element method and assessed the effect of head-model simplifications on the estimated E-field. The deviations from spherical symmetry have large, non-trivial effects on the E-field distribution: in some cases, even the direction of the E-field in the cortex cannot be reliably predicted by the coil orientation unless these deviations are properly considered.

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