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1

Numerical model of heat exchange in perfused tissues

Stańczyk M.

Acta of Bioengineering and Biomechanics

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2007

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Vol. 9, nr 1

24-34

EN

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 mat couples the temperatures of the tissue and of die 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. The presented method allows modelling of the effect of individual blood vessels present m the tissue domain on the heat transfer. It is significantly more expensive computationally than continuum models. At the same time, it is numerically cheaper man most vascular models known in the literature. The present implementation can be extended to cover 3D geometry and thermoregulation effects [vasoconstriction and vasodilation) at moderate cost.

2

Velocity and flow evaluation in vascular models with stents

Liepsch D., Sakurai A., Tiefenbacher T., Berger H., Kleinschmidt T., Greil O.

Elektronika : konstrukcje, technologie, zastosowania

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2004

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Vol. 45, nr 8-9

114-117

EN

Three different stent types at various positions in elastic replicas of carotid bifurcation were studied to determine which would be the most effective and safe. Ali experiments were done under physiological flow conditions using a blood-like fluid. Flow velocity distributions were evaluated qualitatively (visualization) and quantitatively (LDA measurements). Findings were compared with that for a healthy carotid artery model without stent. Stents used in the experiments demonstrated different influence on the flow velocity distribution.

PL

Przebadano trzy rodzaje stentów wewnątrznaczyniowych, różnie zlokalizowanych w modelach tętnicy szyjnej, w ceu określenia który z nich jest najbardziej użyteczny i bezpieczny. Wszystkie eksperymenty zostały wykonane w warunkach przepływu fizjologicznego z użyciem reologicznego modelu krwi. Rozkłady prędkości przepływu zostały ocenione jakościowo (wizualizacja) i ilościowo (pomiary z użyciem dopplerowskiego przepływomierza laserowego). Uzyskane rezultaty porównano z pomiarami przepływu w modelu zdrowej tętnicy szyjnej bez stentu. Użyte w badaniach stenty w różnym stopniu wpłynęły na obserwowane rozkłady prędkości przepływu.

3

Modelling of heat transfer in biomechanics - a review. P. 1. Soft tissues

Stańczyk M., Telega J. J.

Acta of Bioengineering and Biomechanics

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2002

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Vol. 4, nr 1

31-61

EN

The aim of this paper is to review available results that pertain to various heat transfer problems of biomechanics. The present part covers the issues connected with modelling of the heat exchange in perfused tissues. The results are important for the design of hyperthermic treatment protocols, thermal injury assessment, heat Ioss rate in adverse environments, constructing whole-body or whole-Iimb models of heat transfer, etc. The division into two classes of models is proposed: continuum models and vascular models (cf. also [3]). The shortcomings of the most popular bioheat transfer equations are discussed. The effects of cryogenic temperatures on living tissues are described in the third part of the paper. The effects of cryogenic temperatures on living tissues arę described in the third part of the paper.