Relaxation Time Effect on the Human Head Using the Thermal Wave Model

2012 ◽  
Author(s):  
Toni K. Tullius ◽  
Yildiz Bayazitoglu
Keyword(s):  
Relaxation Time ◽  
Wave Model ◽  
Human Head ◽  
The Body ◽  
Bioheat Transfer ◽  
Time Dependent ◽  
Head Model ◽  
Transfer Model ◽  
The Waves ◽  
The Brain

The most common electronics used by the vast majority of the world’s population emit low radio frequencies and they may be harmful to both skin and brain tissue. The bio-heat transfer model is numerically solved to predict the time dependent temperature distribution of micro waves as it emits to the brain caused by everyday electronics in order to understand the effects the waves have on our organs. A time dependent finite difference technique is used to model a multilayer system depicting this external heat source passing through skin, bone, and into the brain. This model accounts for the extra heat generated within the body from the chemical reactions of the tissue, whereas pervious work took this heat sources to be negligible. A relaxation time is also included in the bioheat transfer model in order to account for the response time the tissue takes caused by the perturbation. Most studies neglect this parameter. Parameters for the adult and child head model are compared. The manuscript is aimed to understand the potential threats on the human body caused by everyday use of the technologies such as Ipods, cellular phones, bluetooth’s, etc.

scholarly journals Small Triple-Band Meandered PIFA for Brain-Implantable Biotelemetric Systems: Development and Testing in a Liquid Phantom

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Nikta Pournoori ◽  
Lauri Sydänheimo ◽  
Yahya Rahmat-Samii ◽  
Leena Ukkonen ◽  
Toni Björninen
Keyword(s):  
State Of The Art ◽  
Data Communication ◽  
Human Head ◽  
The Body ◽  
Head Model ◽  
Wireless Power ◽  
Wireless Data ◽  
Full Wave ◽  
Implantable Antennas ◽  
Triple Band

We present a meandered triple-band planar-inverted-F antenna (PIFA) for integration into brain-implantable biotelemetric systems. The target applications are wireless data communication, far-field wireless power transfer, and switching control between sleep/wake-up mode at the Medical Device Radiocommunication Service (MedRadio) band (401–406 MHz) and Industrial, Scientific and Medical (ISM) bands (902–928 MHz and 2400–2483.5 MHz), respectively. By embedding meandered slots into the radiator and shorting it to the ground, we downsized the antenna to the volume of 11 × 20.5 × 1.8 mm3. We optimized the antenna using a 7-layer numerical human head model using full-wave electromagnetic field simulation. In the simulation, we placed the implant in the cerebrospinal fluid (CSF) at a depth of 13.25 mm from the body surface, which is deeper than in most works on implantable antennas. We manufactured and tested the antenna in a liquid phantom which we replicated in the simulator for further comparison. The measured gain of the antenna reached the state-of-the-art values of −43.6 dBi, −25.8 dBi, and −20.1 dBi at 402 MHz, 902 MHz, and 2400 MHz, respectively.

Biomechanical Analysis of the Sensitivity of Brain Tissue Responses to FE Head Models in the Study of Impact-Induced TBI

2020 ◽  
Author(s):  
Hesam S. Moghaddam ◽  
Asghar Rezaei ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Shear Stress ◽  
Mesh Size ◽  
Human Head ◽  
Biomechanical Analysis ◽  
Head Model ◽  
Tissue Responses ◽  
Stress Prediction ◽  
Brain Material ◽  
The Brain

Abstract A numerical investigation is conducted on the injury-related biomechanical parameters of the human head under blunt impacts. The objective of this research is twofold; first to understand the role of the employed finite element (FE) head model — with its specific components, shape, size, material properties, and mesh size — in predicting tissue responses of the brain, and second to investigate the fidelity of pressure response in validating FE head models. Accordingly, two independently established and validated FE head models are impacted in two directions under two impact severities and their predicted responses in terms of intracranial pressure (ICP) and shear stress are compared. The coup-counter ICP peak values are less sensitive to head model, mesh size, and the brain material. In all cases, maximum ICPs occur on the outer surface, vanishing linearly toward the center of the brain. Hence, it is concluded that different head models may simply reproduce the results of ICP variations due to impact. Shear stress prediction, however, is mainly affected by the head model, direction and severity of impact, and the brain material.

Computation of Blast-Induced Traumatic Brain Injury

2009 ◽  
Author(s):  
M. S. Chafi ◽  
G. Karami ◽  
M. Ziejewski
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Blast Wave ◽  
Human Head ◽  
Propagation Model ◽  
Head Model ◽  
Brain Response ◽  
Brain Responses ◽  
The Impact ◽  
The Brain

In this paper, an integrated numerical approach is introduced to determine the human brain responses when the head is exposed to blast explosions. The procedure is based on a 3D non-linear finite element method (FEM) that implements a simultaneous conduction of explosive detonation, shock wave propagation, and blast-brain interaction of the confronting human head. Due to the fact that there is no reported experimental data on blast-head interactions, several important checkpoints should be made before trusting the brain responses resulting from the blast modeling. These checkpoints include; a) a validated human head FEM subjected to impact loading; b) a validated air-free blast propagation model; and c) the verified blast waves-solid interactions. The simulations presented in this paper satisfy the above-mentioned requirements and checkpoints. The head model employed here has been validated again impact loadings. In this respect, Chafi et al. [1] have examined the head model against the brain intracranial pressure, and brain’s strains under different impact loadings of cadaveric experimental tests of Hardy et al. [2]. In another report, Chafi et al. [3] has examined the air-blast and blast-object simulations using Arbitrary Lagrangian Eulerian (ALE) multi-material and Fluid-Solid Interaction (FSI) formulations. The predicted results of blast propagation matched very well with those of experimental data proving that this computational solid-fluid algorithm is able to accurately predict the blast wave propagation in the medium and the response of the structure to blast loading. Various aspects of blast wave propagations in air as well as when barriers such as solid walls are encountered have been studied. With the head model included, different scenarios have been assumed to capture an appropriate picture of the brain response at a constant stand-off distance of nearly 80cm (2.62 feet) from the explosion core. The impact of brain response due to severity of the blast under different amounts of the explosive material, TNT (0.0838, 0.205, and 0.5lb) is examined. The accuracy of the modeling can provide the information to design protection facilities for human head for the hostile environments.

Development and validation of a new finite element human head model

2018 ◽  
Vol 35 (1) ◽  
pp. 477-496 ◽  
Author(s):  
Fábio A.O. Fernandes ◽  
Dmitri Tchepel ◽  
Ricardo J. Alves de Sousa ◽  
Mariusz Ptak
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Human Head ◽  
Design Tool ◽  
Head Model ◽  
Accident Reconstruction ◽  
Research Groups ◽  
Content Type ◽  
Development And Validation ◽  
The Brain

Purpose Currently, there are some finite element head models developed by research groups all around the world. Nevertheless, the majority are not geometrically accurate. One of the problems is the brain geometry, which usually resembles a sphere. This may raise problems when reconstructing any event that involves brain kinematics, such as accidents, affecting the correct evaluation of resulting injuries. Thus, the purpose of this study is to develop a new finite element head model more accurate than the existing ones. Design/methodology/approach In this work, a new and geometrically detailed finite element brain model is proposed. Special attention was given to sulci and gyri modelling, making this model more geometrically accurate than currently available ones. In addition, these brain features are important to predict specific injuries such as brain contusions, which usually involve the crowns of gyri. Findings The model was validated against experimental data from impact tests on cadavers, comparing the intracranial pressure at frontal, parietal, occipital and posterior fossa regions. Originality/value As this model is validated, it can be now used in accident reconstruction and injury evaluation and even as a design tool for protective head gear.

scholarly journals Development of a Finite Element Head Model for the Study of Impact Head Injury

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Bin Yang ◽  
Kwong-Ming Tse ◽  
Ning Chen ◽  
Long-Bin Tan ◽  
Qing-Qian Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Brain Injuries ◽  
Current Knowledge ◽  
Human Head ◽  
Von Mises Stress ◽  
Head Model ◽  
Fe Model ◽  
Prediction And Prevention ◽  
Von Mises ◽  
The Brain

This study is aimed at developing a high quality, validated finite element (FE) human head model for traumatic brain injuries (TBI) prediction and prevention during vehicle collisions. The geometry of the FE model was based on computed tomography (CT) and magnetic resonance imaging (MRI) scans of a volunteer close to the anthropometry of a 50th percentile male. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue. The cerebrospinal fluid (CSF) was simulated explicitly as a hydrostatic fluid by using a surface-based fluid modeling method. The model was validated in the loading condition observed in frontal impact vehicle collision. These validations include the intracranial pressure (ICP), brain motion, impact force and intracranial acceleration response, maximum von Mises stress in the brain, and maximum principal stress in the skull. Overall results obtained in the validation indicated improved biofidelity relative to previous FE models, and the change in the maximum von Mises in the brain is mainly caused by the improvement of the CSF simulation. The model may be used for improving the current injury criteria of the brain and anthropometric test devices.

scholarly journals A simplified human head finite element model for brain injury assessment of blunt impacts

2020 ◽  
Vol 14 (2) ◽  
pp. 6538-6547 ◽  
Author(s):  
M.H.A. Hassan ◽  
Z. Taha ◽  
I. Hasanuddin ◽  
A.P.P.A. Majeed ◽  
H. Mustafa ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Human Head ◽  
Brain Trauma ◽  
Head Model ◽  
Human Cadaver ◽  
Brain Responses ◽  
Dimensional Models ◽  
The Brain ◽  
Head Neck

Blunt impacts contribute more than 95% of brain trauma injuries in Malaysia. Modelling and simulation of these impacts are essential in understanding the mechanics of the injuries to develop a protective equipment that might prevent brain trauma. Various finite element models of human head have been developed, ranging from two-dimensional models to very complex three-dimensional models. The aim of this study is to develop a simplified three-dimensional human head model with low computational cost, yet capable of producing reliable brain responses. The influence of different head-neck boundary conditions on the brain responses were also examined. Our model was validated against an experimental work on human cadaver. The model with free head-neck boundary condition was found to be in good agreement with experimental results. The head-neck joint was found to have a significant influence on the brain responses upon impact. Further investigations on the head-neck joint modelling are needed. Our simplified model was successfully validated against experimental data on human cadaver and could be used in simulating blunt impact scenarios.

scholarly journals BRAIN THERMAL AND ELECTRICAL PROPERTIES ESTIMATION USING EXPERIMENTAL DATA FROM DEEP BRAIN STIMULATION LEAD

2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Lucas Correia da Silva Jardim ◽  
Luiz Alberto da Silva Abreu ◽  
Diego Campos Knupp ◽  
Antônio José da Silva Neto
Keyword(s):  
Experimental Data ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Bioheat Transfer ◽  
Transfer Model ◽  
Physiological Effects ◽  
Electrical Conductivities ◽  
Thermal And Electrical Properties ◽  
The Brain ◽  
Deep Brain

Deep Brain Stimulation (DBS) is a well-established neurosurgery that alleviates the symptoms of several movement disorders and other brain related conditions. It works by placing a small lead containing electrodes inside the patient's brain and using them to electrically stimulate that area. Although this procedure is very common, little is known about its physiological effects on the brain and, on top of that, injuries caused from burning have been reported. The present work intends to formulate and solve a bioheat transfer model of the brain containing a DBS lead and, furthermore, to use this solution for solving an inverse problem of determining the thermal and electrical conductivities of the brain tissue using measurements supposedly obtained with a sensor inside the DBS lead.The results revealed that it is possible to estimate the both parameters especially when the measurements uncertainties are relatively small.

scholarly journals Influence of Blood Vessels on Temperature during High-Intensity Focused Ultrasound Hyperthermia Based on the Thermal Wave Model of Bioheat Transfer

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Qiaolai Tan ◽  
Xiao Zou ◽  
Hu Dong ◽  
Yajun Ding ◽  
Xinmin Zhao
Keyword(s):  
Blood Flow ◽  
Relaxation Time ◽  
Blood Vessel ◽  
Focused Ultrasound ◽  
Thermal Relaxation ◽  
Wave Model ◽  
High Intensity Focused Ultrasound ◽  
Thermal Relaxation Time ◽  
Bioheat Transfer ◽  
Thermal Lesion

The coupled effects of blood vessels and thermal relaxation time on temperature and thermal lesion region in biological tissue during high-intensity focused ultrasound (HIFU) hyperthermia are numerically investigated. Considering the non-Fourier behavior of heat conduction in biological tissue, the traditional Pennes bioheat equation was modified to thermal wave model of bioheat transfer (TWMBT). Consequently, a joint physical model, which combines TWMBT for tissue and energy transport equation for blood vessel, is presented to predict the evolution of temperature and the thermal lesion region. In this study, pulsatile blood flow is first introduced into numerical study of HIFU hyperthermia, and thermal relaxation time, ultrasonic focus location, blood vessel radius, and blood flow velocity are all taken into account. The results show that the thermal relaxation time plays a key role in the temperature and the thermal lesion region. Larger thermal relaxation time results in lower temperature and smaller thermal lesion region, which indicates that TWMBT leads to lower temperature and smaller thermal lesion region compared to Pennes bioheat transfer model. In addition, we found that the ultrasonic focus location and blood vessel radius significantly affected the temperature and thermal lesion region, while the heartbeat frequency and amplitude factor of pulsating blood flow as well as the average velocity of blood flow had only a slight effect.

scholarly journals An Inverse Scattering Approach Based on Inhomogeneous Medium Green's Functions for Microwave Imaging of Brain Strokes

2019 ◽  
Vol 8 (2) ◽  
pp. 53-58
Author(s):  
E. Konakyeri Arıcı ◽  
A. Yapar
Keyword(s):  
Inhomogeneous Medium ◽  
Inverse Scattering ◽  
Scattering Problem ◽  
Inverse Scattering Problem ◽  
Human Head ◽  
Numerical Approach ◽  
Head Model ◽  
Background Space ◽  
The Difference ◽  
The Brain

In this study, an inverse scattering approach is investigated for the detection and imaging of an abnormal structure (a bleeding or a stroke) inside the human brain. The method is mainly based on the solution of an integral equation whose kernel is the Green’s function of the inhomogeneous medium (corresponding to a human head model) which is obtained by a numerical approach based on Method of Moments (MoM). In this context, an inverse scattering problem related to the difference of healthy and unhealthy brain models is formulated and a difference function is obtained which indicates the region where the anomaly is located by solving this inverse problem. In order to reduce the reflection effects caused by the electromagnetic differences between the free space and the brain, a matching medium is used as the background space.

Simulation of Blast Induced Traumatic Brain Injury using Finite Element Method

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
G. Krishnaveni ◽  
D. Dominic Xavier ◽  
R. Sarathkumar ◽  
G. Kavitha ◽  
M. Senbagan
Keyword(s):  
Traumatic Brain Injury ◽  
Finite Element ◽  
Brain Injury ◽  
Blast Wave ◽  
Ambient Pressure ◽  
Memory Loss ◽  
Human Head ◽  
Head Model ◽  
Stress Concentrations ◽  
The Brain

Because of increase in threat from militant groups and during war exposure to blast wave from improvised explosive devices, Traumatic Brain Injury (TBI), a signature injury is on rise worldwide. During blast, the biological system is exposed to a sudden blast over pressure which is several times higher than the ambient pressure causing the damage in the brain. The severity of TBI due to air blast may vary from brief change in mental status or consciousness (termed as mild) to extended period of unconsciousness or memory loss after injuries (termed as severe). The blast wave induced impact on head propagates as shock wave with the broad spectrum of frequencies and stress concentrations in the brain. The primary blast TBI is directly induced by pressure differentials across the skull/fluid/soft tissue interfaces and is further reinforced by the reflected stress waves within the cranial cavity, leading to stress concentrations in certain regions of the brain. In this paper, an attempt has been made to study the behaviour of a human brain model subjected to blast wave based on finite element model using LSDYNA code. The parts of a typical human head such as skull, scalp, CSF, brain are modelled using finite element with properties assumed based on available literature. The model is subjected to blast from frontal lobe, occipital lobe, temporal lobe of the brain. The interaction of the blast wave with the head and subsequent transformation of various forms of shock energy internally have been demonstrated in the human head model. The brain internal pressure levels and the shear stress distribution in the various lobes of the brain such as frontal, parietal, temporal and occipital are determined and presented.

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