Marek Paruch

Identification of tumor region parameters using evolutionary algorithm and multiple reciprocity boundary element method

In the paper the inverse problems consisting in the simultaneous estimation of unknown thermophysical and/or geometrical parameters (thermal conductivity, perfusion coefficient, metabolic heat source, location, size) of the tumor region are solved. The additional information concerning the knowledge of local skin surface temperature at the selected set of points is assumed to be known. The problem of thermal processes proceeding in the domain considered is described by the system of the Pennes equations and boundary conditions given on the outer and contact surfaces. On the stage of numerical solution the evolutionary algorithm coupled with the multiple reciprocity boundary element method has been applied.

Identification of electromagnetic field parameters assuring the cancer destruction during hyperthermia treatment

Electromagnetic field induced by two external electrodes and temperature field resulting from electrode action in the domain of biological tissue being a composition of healthy region and a tumour is considered. To warrant the optimum conditions of tumour destruction, the magnetic nanoparticles are embedded in this region. It is assumed that the temperature which assures an effect of destruction should be higher than 42°C. In this article, the problems relating to the electrodes’ electric potential identification and the simultaneous identification of potential and number of nanoparticles introduced to the tumour region are discussed. Additional information necessary to solve the task results from the postulated temperature inside the tumour region assuring its destruction. The problem has been solved using both the gradient method and evolutionary algorithm. The boundary element method is applied to solve the coupled problem connected with the heating of biological tissues.

Sensitivity Analysis of Temperature Field and Parameter Identification in Burned and Healthy Skin Tissue

In the chapter, problems connected with the numerical modeling of bioheat transfer processes are presented. In particular the non-homogeneous system of a burn wound and healthy tissue is considered. The heat exchange between sub-domains and environment is described by a system of partial differential equations (the Pennes equations) supplemented by adequate boundary conditions. The first goal of the research is the estimation of the changes of temperature fields due to perturbations in thermal parameters using the direct method of sensitivity analysis. Both the basic problem and additional ones concerning the sensitivity with respect to selected parameters are solved using the boundary element method. The second goal is the problem of burn wound shape identification. The additional information necessary to solve such a task results from the knowledge of temperature distribution on the external surface of skin tissue. At the stage of solving the inverse problem, a gradient method has been used. In the final part of the chapter the results of computations are shown.

Soft tissue freezing process. Identification of the dual-phase lag model parameters using the evolutionary algorithm

In the paper the soft tissue freezing process is considered. The tissue sub-domain is subjected to the action of cylindrical cryoprobe. Thermal processes proceeding in the domain considered are described using the dual-phase lag equation (DPLE) supplemented by the appropriate boundary and initial conditions. DPLE results from the generalization of the Fourier law in which two lag times are introduced (relaxation and thermalization times). The aim of research is the identification of these parameters on the basis of measured cooling curves at the set of points selected from the tissue domain. To solve the problem the evolutionary algorithms are used. The paper contains the mathematical model of the tissue freezing process, the very short information concerning the numerical solution of the basic problem, the description of the inverse problem solution and the results of computations.In the paper the soft tissue freezing process is considered. The tissue sub-domain is subjected to the action of cylindrical cryoprobe. Thermal processes proceeding in the domain considered are described using the dual-phase lag equation (DPLE) supplemented by the appropriate boundary and initial conditions. DPLE results from the generalization of the Fourier law in which two lag times are introduced (relaxation and thermalization times). The aim of research is the identification of these parameters on the basis of measured cooling curves at the set of points selected from the tissue domain. To solve the problem the evolutionary algorithms are used. The paper contains the mathematical model of the tissue freezing process, the very short information concerning the numerical solution of the basic problem, the description of the inverse problem solution and the results of computations.