Bioheat Transfer
Seyed Alireza Zolfaghari; Mehdi Maerefat; Amir Omidvar
Volume 4, Issue 1 , June 2010, , Pages 13-21
Abstract
Generally, most of the human thermal response models are dependent upon a narrow range of personal/environmental parameters. In other words, the effects of other parameters such as eating foods are not considered in these models. On the other hand, previous studies have indicated that the overall thermal ...
Read More
Generally, most of the human thermal response models are dependent upon a narrow range of personal/environmental parameters. In other words, the effects of other parameters such as eating foods are not considered in these models. On the other hand, previous studies have indicated that the overall thermal condition of the body can be significantly affected by eating cold or hot foods. In the present study, the time-dependent thermal response of the human body is simulated with considering the effect of eating hot/cold food. This simulation is performed by adding an extra term to Gagge’s transient model. In this study, three thermal conditions of the human body (hot, neutral and cold) are considered and the effects of eating hot/cold food are investigated under the mentioned conditions. Results indicate that the effects of eating hot or cold food are not negligible during the eating time and also in a period of time after that. At the neutral condition, the human thermal sensation is more sensitive to hot food than to cold ones. Eating hot food changes the body thermal sensation from neutral to hot. But, eating cold food would not make significant changes in the thermal sensation of the body. Results also show that cold food changes the body core temperature more than hot food. While hot food influences the skin temperature significantly.
Bioheat Transfer
Mehdi Maerefat; Manije Mokhtari Dizaji; Zahra Haddad Soleimani
Volume 3, Issue 3 , June 2009, , Pages 189-197
Abstract
In this paper a comprehensive mathematical model for thermal analysis of liver tissue in thermotherapy of liver cancer by laser is presented. In the present model the diffusion approximation analytical method for radiative heat transfer modeling of heat transfer process in the tissue is used for the ...
Read More
In this paper a comprehensive mathematical model for thermal analysis of liver tissue in thermotherapy of liver cancer by laser is presented. In the present model the diffusion approximation analytical method for radiative heat transfer modeling of heat transfer process in the tissue is used for the first time. Heat transfer modeling in the biological tissue is carried out using Penes model taking into account the influence of thermal and blood perfusion coefficient fluctuations due to temperature changes as well as the effect of lipid melting on temperature distribution through enthalpy method is taken into account. In the present study the tumor is considered as a sphere with thermo-physical properties different with those of healthy tissue. Finally, the obtained non-linear equations are solved using the numerical finite volume method. Temperature distribution at several instants during the thermotherapy is calculated. The comparison of the calculated results with those of experimental results indicate a good agreement between the results. Furthermore, the effects of different parameters such as laser specifications and optic coefficient changes (through proper photopherin injection) on laser-affected area are studied using the present analytical method. These results can help the specialists in order to come upon a safe LITT method for destruction of cancerous tissues without harming the healthy ones.
Cardiovascular Biomechanics
Mehdi Maerefat; Asghar Khoushkar Shalmani; Manije Mokhtari Dizaji
Volume 1, Issue 2 , June 2007, , Pages 95-104
Abstract
Modeling of blood flow and arterial wall in large arteries such as carotid artery, using ultrasonic measurements, allows non-invasive evaluation of clinically interesting homodynamic variables. In this study, a nonlinear mathematical model for the pulsatile arterial flow is proposed using the approximation ...
Read More
Modeling of blood flow and arterial wall in large arteries such as carotid artery, using ultrasonic measurements, allows non-invasive evaluation of clinically interesting homodynamic variables. In this study, a nonlinear mathematical model for the pulsatile arterial flow is proposed using the approximation of “local flow” theory. The blood velocity profile, the pressure gradient and the elastic modulus can be calculated using the model by measuring instantaneous radius and center-line blood velocity. An original mathematical model of pressure gradient in a tapered and elastic tube, using center-line blood velocity, is presented. A Newtonian incompressible Navier-Stokes solver coupled with elastic or visco-elastic arterial wall model is developed to solve the equations of model. The results of modeling and simulation indicate that the approach can estimate the elastic modulus of arterial wall from ultrasonic data. There is a good agreement between the computed arterial wall elasticity and the measured one. The method presented is relatively simple to implement clinically and can be taken as a new diagnostic tool for detecting local vascular change.
