Space-dependent perfusion coefficient estimation in a 2D bioheat transfer problem

2017 ◽  
Vol 214 ◽  
pp. 18-30 ◽  
Author(s):  
Fermín S.V. Bazán ◽  
Luciano Bedin ◽  
Leonardo S. Borges
Keyword(s):  
Transfer Problem ◽  
Bioheat Transfer ◽  
Coefficient Estimation ◽  
Perfusion Coefficient

Effect of Forced Convection on the Skin Thermal Expression of Breast Cancer

2004 ◽  
Vol 126 (2) ◽  
pp. 204-211 ◽  
Author(s):  
Lu Hu ◽  
Ashish Gupta ◽  
Jay P. Gore ◽  
Lisa X. Xu
Keyword(s):  
Forced Convection ◽  
Conjugate Heat Transfer ◽  
Transfer Problem ◽  
Skin Surface ◽  
Bioheat Transfer ◽  
Image Subtraction ◽  
Steady State Temperature ◽  
Parametric Studies ◽  
Airflow Field ◽  
Thermal Signature

A bioheat-transfer-based numerical model was utilized to study the energy balance in healthy and malignant breasts subjected to forced convection in a wind tunnel. Steady-state temperature distributions on the skin surface of the breasts were obtained by numerically solving the conjugate heat transfer problem. Parametric studies on the influences of the airflow on the skin thermal expression of tumors were performed. It was found that the presence of tumor may not be clearly shown due to the irregularities of the skin temperature distribution induced by the airflow field. Nevertheless, image subtraction techniques could be employed to eliminate the effects of the flow field and thermal noise and significantly improve the thermal signature of the tumor on the skin surface. Inclusion of the possible skin vascular response to cold stress caused by the airflow further enhances the signal, especially for deeply embedded tumors that otherwise may not be detectable.

Solution of the Inverse Bioheat Transfer Problem for the Detection of Tumors by Genetic Algorithms

2017 ◽  
pp. 441-452
Author(s):  
Antonio Marcio Gonçalo Filho ◽  
Lucas Lagoa Nogueira ◽  
Joao Victor Caetano Silveira ◽  
Michelli Marlane Silva Loureiro ◽  
Felipe dos Santos Loureiro
Keyword(s):  
Genetic Algorithms ◽  
Transfer Problem ◽  
Bioheat Transfer

Inverse Heat Transfer Analysis of Micro Heater Strength and Locations for Hyperthermia Treatment of Brain Tumors

2007 ◽  
Author(s):  
Maral Biniazan ◽  
Kamran Mohseni
Keyword(s):  
Heat Transfer ◽  
Brain Tumors ◽  
Transfer Problem ◽  
The Body ◽  
Least Square ◽  
Bioheat Transfer ◽  
Heat Transfer Analysis ◽  
Whole Body ◽  
Transient Temperature ◽  
Inverse Heat Transfer

Hyperthermia, also called thermal therapy or thermotherapy, is a type of cancer treatment in which the aim is to maintain the surrounding healthy tissue at physiologically normal temperatures and expose the cancerous region to high temperatures between 43°C–45°C. Several methods of hyperthermia are currently under study, including local, regional, and whole-body hyperthermia. In local hyperthermia, Interstitial techniques are used to treat tumors deep within the body, such as brain tumors. heat is applied to the tumor, usually by probes or needles which are inserted into the tumor. The heat source is then inserted into the probe. Invasive interstitial heating technique offer a number of advantages over external heating approaches for localizing heat into small tumors at depth. e. g interstitial technique allows the tumor to be heated to higher temperatures than external techniques. This is why an innovative internal hyperthermia research is being conducted in the design of an implantable microheater [1]. To proceed with this research we need complete and accurate data of the strength, number and location of the micro heaters, which is the objective of this paper. The location, strength, and number of implantable micro heaters for a given tumor size is calculated by solving an Inverse Heat Transfer Problem (IHTP). First we model the direct problem by calculating the transient temperature field via Pennies bioheat transfer equation. A nonlinear least-square method, modified by addition of a regularization term, Levenberg Marquardt method is used to determine the inverse problem [2].

Identification of the cancer ablation parameters during RF hyperthermia using gradient, evolutionary and hybrid algorithms

2017 ◽  
Vol 27 (3) ◽  
pp. 674-697 ◽  
Author(s):  
Marek Paruch
Keyword(s):  
Inverse Problem ◽  
Temperature Field ◽  
Electric Field ◽  
Electric Potential ◽  
Biological Tissue ◽  
Transfer Problem ◽  
Biological Tissues ◽  
Bioheat Transfer ◽  
System Of Equations ◽  
Content Type

Purpose The purpose of this study is to show that the methods of the numerical simulation can be a very effective tool for a proper choice of control parameters of artificial hyperthermia. An electromagnetic field induced by two external electrodes and a temperature field resulting from electrodes action in a 3D domain of biological tissue is considered. An important problem is the appropriate directing of heat in the region of tumor, so as to avoid damaging healthy cells surrounding the tumor. Recently, to concentrate the heat on the tumor, magnetic nanoparticles, which are introduced into the tumor, were used. The nanoparticles should be made of material that ensures appropriate magnetic properties and has a high biocompatibility with the biological tissue. External electric field causes the heat generation in the tissue domain. Design/methodology/approach The distribution of electric potential in the domain considered is described by the Laplace system of equations, while the temperature field is described by the Pennes’ system of equations. These problems are coupled by source function being the additional component in the Pennes’ equation and resulting from the electric field action. The boundary element method is applied to solve the coupled problem connected with the heating of biological tissues. Findings The aim of investigations is to determine an electric potential of external electrodes and the number of nanoparticles introduced to a tumor region to obtain the artificial hyperthermia state. The tests performed showed that the proposed tool to solve the inverse problem provides correct results. Research limitations/implications In the paper the steady state bioheat transfer problem is considered, so the thermal damage is a function of the temperature only. Therefore, the solution can be considered as the maximum ablation zone of cancer. Additionally, the choice of appropriate parameters will be affected on the position and shape of the tumor and the electrodes. Originality/value In the paper the inverse problem has been solved using the evolutionary algorithm, gradient method and hybrid algorithm which is a combination of the two previous.

scholarly journals Analysis of the effect of external heating in the human tissue: A finite element approach

2020 ◽  
Vol 26 (4) ◽  
pp. 251-262
Author(s):  
Mridul Sannyal ◽  
Abul Mukid Mohammad Mukaddes ◽  
Md. Matiar Rahman ◽  
M. A. H. Mithu
Keyword(s):  
Finite Element ◽  
Human Tissue ◽  
Transfer Problem ◽  
Thermal Response ◽  
Blood Perfusion ◽  
Element Model ◽  
Bioheat Transfer ◽  
Tissue Temperature ◽  
Blood Temperature ◽  
External Heating

AbstractThermal therapy which involves either raising or lowering tissue temperature to treat malignant cells needs precise acknowledgment of thermal history inside the biological system to ensure effective treatment. For this purpose, this study presents a two-dimensional unsteady finite element model (FEM) of the bioheat transfer problem based on Pennes bio-heat equation to analyze the thermal response of tissue subject to external heating. Crank-Nikolson scheme was used for the unsteady solution. A finite element code was developed using C language to calculate results. The obtained numerical result was compared with the analytical and other numerical results available in the literature. A good agreement was found from the comparison. Temperature distribution inside the human body due to constant and sinusoidal spatial and surface heating were analyzed. Response to point heating was also investigated. Moreover, a sensitivity analysis was carried out to know the effect of various parameters, i.e. blood temperature, thermal conductivity, and blood perfusion rate on tissue temperature. The outcome of this study will be helpful for the researchers and physicians involved in the thermal treatment of human tissue.

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