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Bioheat formulation

Federico Schaumburg, Fabio Guarnieri
A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such device, located in the temporal superior eye quadrant, produces a filtering bleb which is included in the geometry of the model, together with relevant ocular structures. The electromagnetic field source, a planar coil, and the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method...
February 2, 2017: Physics in Medicine and Biology
Magdy A Ezzat, Alaa A El-Bary, Noorah S Al-Sowayan
A fractional model of Bioheat equation for describing quantitatively the thermal responses of skin tissue under sinusoidal heat flux conditions on skin surface is given. Laplace transform technique is used to obtain the solution in a closed form. The resulting formulation is applied to one-dimensional application to investigate the temperature distribution in skin with instantaneous surface heating for different cases. According to the numerical results and its graphs, conclusion about the fractional bioheat transfer equation has been constructed...
October 2016: Animal Science Journal, Nihon Chikusan Gakkaihō
Asnida Abd Wahab, Maheza Irna Mohamad Salim, Mohamad Asmidzam Ahamat, Noraida Abd Manaf, Jasmy Yunus, Khin Wee Lai
Breast cancer is the most common cancer among women globally, and the number of young women diagnosed with this disease is gradually increasing over the years. Mammography is the current gold-standard technique although it is known to be less sensitive in detecting tumors in woman with dense breast tissue. Detecting an early-stage tumor in young women is very crucial for better survival chance and treatment. The thermography technique has the capability to provide an additional functional information on physiological changes to mammography by describing thermal and vascular properties of the tissues...
September 2016: Medical & Biological Engineering & Computing
C W Huang, M K Sun, B T Chen, J Shieh, C S Chen, W S Chen
An integrated computational framework was developed in this study for modeling high-intensity focused ultrasound (HIFU) thermal ablation. The temperature field was obtained by solving the bioheat transfer equation (BHTE) through the finite element method; while, the thermal lesion was considered as a denatured material experiencing phase transformation and modeled with the latent heat. An equivalent attenuation coefficient, which considers the temperature-dependent properties of the target material and the ultrasound diffraction due to bubbles, was proposed in the nonlinear thermal transient analysis...
November 2015: Ultrasonics Sonochemistry
Cecilia Suárez, Alejandro Soba, Felipe Maglietti, Nahuel Olaiz, Guillermo Marshall
Electropermeabilization (EP) based protocols such as those applied in medicine, food processing or environmental management, are well established and widely used. The applied voltage, as well as tissue electric conductivity, are of utmost importance for assessing final electropermeabilized area and thus EP effectiveness. Experimental results from literature report that, under certain EP protocols, consecutive pulses increase tissue electric conductivity and even the permeabilization amount. Here we introduce a theoretical model that takes into account this effect in the application of an EP-based protocol, and its validation with experimental measurements...
2014: PloS One
Manu Mital, Hooman V Tafreshi
Hyperthermia treatment of tumors uses localized heating to damage cancer cells and can also be utilized to increase the efficacy of other treatment methods such as chemotherapy. Magnetic nanoparticle hyperthermia is one of the least invasive techniques of delivering heat. It is based on injecting magnetic nanoparticles into the tumor and subjecting them to an alternating magnetic field. The technique is aimed at damaging the tumor without affecting the surrounding healthy tissue. In this preliminary study, we consider a simplified model (two concentric spheres that represent the tumor and its surrounding tissues) that employs a numerical solution of the Pennes bioheat equation...
February 2012: International Journal for Numerical Methods in Biomedical Engineering
Ewa Majchrzak
Heat transfer processes proceeding in the living organisms are described by the different mathematical models. In particular, the typical continuous model of bioheat transfer bases on the most popular Pennes equation, but the Cattaneo-Vernotte equation and the dual phase lag equation are also used. It should be pointed out that in parallel are also examined the vascular models, and then for the large blood vessels and tissue domain the energy equations are formulated separately. In the paper the different variants of the boundary element method as a tool of numerical solution of bioheat transfer problems are discussed...
September 2013: Molecular & Cellular Biomechanics: MCB
Shong-Leih Lee, Yung-Hsiang Lu
Heat transfer in a unit three-dimensional skin tissue with an embedded vascular system of actual histology structure is computed in the present work. The tissue temperature and the blood temperatures in artery and vein vessels are solved with a multi-grid system. The mean temperature of the tissue over the cross-section of the unit skin area is evaluated. The resulting one-dimensional function is regarded as the temperature of healthy tissue (or injured skin but the blood perfusion is still normally working) for large area of skin in view of the symmetric and periodic structure of the paired artery-vein vessels in nature...
August 2014: Burns: Journal of the International Society for Burn Injuries
Petr V Yuldashev, Svetlana M Shmeleva, Sergey A Ilyin, Oleg A Sapozhnikov, Leonid R Gavrilov, Vera A Khokhlova
The goal of this study was to investigate theoretically the effects of nonlinear propagation in a high-intensity focused ultrasound (HIFU) field produced by a therapeutic phased array and the resultant heating of tissue behind a rib cage. Three configurations of focusing were simulated: in water, in water with ribs in the beam path and in water with ribs backed by a layer of soft tissue. The Westervelt equation was used to model the nonlinear HIFU field, and a 1 MHz phased array consisting of 254 circular elements was used as a boundary condition to the model...
April 21, 2013: Physics in Medicine and Biology
D Fuentes, A Elliott, J S Weinberg, A Shetty, J D Hazle, R J Stafford
Quantification of local variations in the optical properties of tumor tissue introduced by the presence of gold-silica nanoparticles (NP) presents significant opportunities in monitoring and control of NP-mediated laser induced thermal therapy (LITT) procedures. Finite element methods of inverse parameter recovery constrained by a Pennes bioheat transfer model were applied to estimate the optical parameters. Magnetic resonance temperature imaging (MRTI) acquired during a NP-mediated LITT of a canine transmissible venereal tumor in brain was used in the presented statistical inverse problem formulation...
January 2013: Annals of Biomedical Engineering
Mohamad Feras Marqa, Serge Mordon, Esteban Hernández-Osma, Mario Trelles, Nacim Betrouni
Endovenous laser treatment (ELT) has been proposed as an alternative in the treatment of reflux of the great saphenous vein. Before the procedure, peri-saphenous subcutaneous tumescent saline solution infiltration is usually performed. However, diffusion of this tumescent fluid is rapidly observed and can potentially reduce the efficacy as a heat sink. External skin cooling with cold air was proposed as an alternative solution. The objective of this study is to compare endovenous laser treatment without and with air cooling by realistic numerical simulations...
May 2013: Lasers in Medical Science
Ze-Wei Zhang, Hui Wang, Qing-Hua Qin
This paper presents a hybrid finite element model for describing quantitatively the thermal responses of skin tissue under laser irradiation. The model is based on the boundary integral-based finite element method and the Pennes bioheat transfer equation. In this study, temporal discretization of the bioheat system is first performed and leads to the well-known modified Helmholtz equation. A radial basis function approach and the boundary integral based finite element method are employed to obtain particular and homogeneous solutions of the laser-tissue interaction problem...
March 2012: Molecular & Cellular Biomechanics: MCB
Katisha D Smith, Liang Zhu
Brain hypothermia induced by a temperature reduction of the spinal fluid using a torso-cooling pad is evaluated as a cooling alternative for traumatic injury patients. A theoretical model of the human head is developed to include its tissue structures and their contribution to local heat transfer. The Pennes bioheat equation and finite element analysis are used to predict the temperature distribution in the head region. The energy balance in the cerebrospinal fluid (CSF) layer surrounding the brain during mixing of the CSF and cold spinal fluid is also formulated to predict the CSF temperature reduction...
August 2010: Medical & Biological Engineering & Computing
Yusheng Feng, David Fuentes, Andrea Hawkins, Jon M Bass, Marissa Nichole Rylander
Predicting the outcome of thermotherapies in cancer treatment requires an accurate characterization of the bioheat transfer processes in soft tissues. Due to the biological and structural complexity of tumor (soft tissue) composition and vasculature, it is often very difficult to obtain reliable tissue properties that is one of the key factors for the accurate treatment outcome prediction. Efficient algorithms employing in vivo thermal measurements to determine heterogeneous thermal tissues properties in conjunction with a detailed sensitivity analysis can produce essential information for model development and optimal control...
2009: Computer Methods in Applied Mechanics and Engineering
Elad Maor, Boris Rubinsky
Tissue ablation finds an increasing use in modern medicine. Nonthermal irreversible electroporation (NTIRE) is a biophysical phenomenon and an emerging novel tissue ablation modality, in which electric fields are applied in a pulsed mode to produce nanoscale defects to the cell membrane phospholipid bilayer, in such a way that Joule heating is minimized and thermal damage to other molecules in the treated volume is reduced while the cells die. Here we present a two-dimensional transient finite element model to simulate the electric field and thermal damage to the arterial wall due to an endovascular NTIRE novel device...
March 2010: Journal of Biomechanical Engineering
Serge R Mordon, Benjamin Wassmer, Jean Pascal Reynaud, Jaouad Zemmouri
BACKGROUND AND OBJECTIVES: Liposuction continues to be one of the most popular procedures performed in cosmetic surgery. As the public's demand for body contouring continues, laser lipolysis has been proposed to improve results, minimize risk, optimize patient comfort, and reduce the recovery period. Mathematical modeling of laser lipolysis could provide a better understanding of the laser lipolysis process and could determine the optimal dosage as a function of fat volume to be removed...
2008: Biomedical Engineering Online
Maciej Stańczyk
A vascular model of the bioheat transfer for perfused tissues is described, along with its numerical implementation. The method consists in creating a vascular tree model within the tissue region of interest and formulating a numerical scheme that couples the temperatures of the tissue and of the arterial and venous blood flowing through it. The necessary equations are derived and cast in finite difference form. The numerical implementation of the method is then used to obtain results for a specific example...
2007: Acta of Bioengineering and Biomechanics
Tzu-Ching Shih, Hong-Sen Kou, Chihng-Tsung Liauh, Win-Li Lin
The aim of this study was to investigate the effects of the propagation speed of a thermal wave in terms of the thermal relaxation time on the temperature/thermal dose distributions in living tissue during thermal therapies. The temperature field in tissue was solved by the finite difference method, and the thermal dose was calculated from the formulation proposed by Sapareto and Dewey [Int. J. Radiat. Oncol. Biol. Phys. 10, 787-800 (1984)]. Under the same total deposited energy, for a rapid heating process the time lagging behavior of the peak temperature became pronounced and the level of the peak temperature was decreased with increasing the thermal relaxation time...
September 2005: Medical Physics
E Y K Ng, L T Chua
To understand and accurately predict tissue damage following a burn, bioheat transfer based mathematical models of the skin were developed. First, mathematical equations with multiple factors to represent the different properties of the various layers of the skin were formulated. These equations were then numerically solved using finite-difference (1-D) and finite-element (2-D) analysis. By application of a standard Arrhenius model for damage rate, the extent of burn injury was computed from the transient temperature solution...
February 2002: Burns: Journal of the International Society for Burn Injuries
Christopher J Yeung, Robert C Susil, Ergin Atalar
With the rapid growth of interventional MRI, radiofrequency (RF) heating at the tips of guidewires, catheters, and other wire-shaped devices has become an important safety issue. Previous studies have identified some of the variables that affect the relative magnitude of this heating but none could predict the absolute amount of heating to formulate safety margins. This study presents the first theoretical model of wire tip heating that can accurately predict its absolute value, assuming a straight wire, a homogeneous RF coil, and a wire that does not extend out of the tissue...
January 2002: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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