Journal ArticleDOI
A New Simplified Bioheat Equation for the Effect of Blood Flow on Local Average Tissue Temperature
Sheldon Weinbaum,Latif M. Jiji +1 more
TLDR
A new simplified three-dimensional bioheat equation is derived to describe the effect of blood flow on blood-tissue heat transfer and shows that the vascularization of tissue causes it to behave as an anisotropic heat transfer medium.Abstract:
A new simplified three-dimensional bioheat equation is derived to describe the effect of blood flow on blood-tissue heat transfer. In two recent theoretical and experimental studies [1, 2] the authors have demonstrated that the so-called isotropic blood perfusion term in the existing bioheat equation is negligible because of the microvascular organization, and that the primary mechanism for blood-tissue energy exchange is incomplete countercurrent exchange in the thermally significant microvessels. The new theory to describe this basic mechanism shows that the vascularization of tissue causes it to behave as an anisotropic heat transfer medium. A remarkably simple expression is derived for the tensor conductivity of the tissue as a function of the local vascular geometry and flow velocity in the thermally significant countercurrent vessels. It is also shown that directed as opposed to isotropic blood perfusion between the countercurrent vessels can have a significant influence on heat transfer in regions where the countercurrent vessels are under 70-micron diameter. The new bioheat equation also describes this mechanism.read more
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Journal ArticleDOI
Tests of the geometrical description of blood vessels in a thermal model using counter-current geometries
TL;DR: The behaviour of the model is examined for counter-current vessel geometries for which a cylindrically symmetric temperature distribution is not valid, and tests show that for a fixed vessel configuration the accuracy is not a simple decreasing function of the voxel dimensions, but is also sensitive to the position of the configuration with respect to the discretized tissue grid.
Journal ArticleDOI
How to apply a discrete vessel model in thermal simulations when only incomplete vessel data are available
TL;DR: An optimal strategy was found to model the missing vessels depending on the available angiographic data and it was found that simulations with a decreased number of discrete vessels, or no vessels at all, yield temperatures which are too high.
Journal ArticleDOI
Hyperthermia treatment planning including convective flow in cerebrospinal fluid for brain tumour hyperthermia treatment using a novel dedicated paediatric brain applicator
G. Schooneveldt,Hana Dobsicek Trefna,Mikael Persson,Theo M. de Reijke,Klas Blomgren,Klas Blomgren,H Petra Kok,Hans Crezee +7 more
TL;DR: This study made treatments plans using the Chalmers Hyperthermia Helmet for both pre-operative and post-operative cases, comparing temperature distributions predicted with three CSF models: a convective “fluid” model, a non-convective ”solid” CSF model, and CSf models with increased effective thermal conductivity (“high-k”).
Journal ArticleDOI
Freezing of Biological Tissues During Cryosurgery Using Hyperbolic Heat Conduction Model
Sonalika Singh,Sushil Kumar +1 more
TL;DR: In this paper, the effects of phase lag of heat flux in hyperbolic bio-heat model on freezing process are studied and comparative study of parabolic and hyperbola heat conduction model is also made.
Journal ArticleDOI
Comparison of temperature distributions in interstitial hyperthermia: experiments in bovine tongues versus generic simulations
TL;DR: Temperature distributions resulting from hyperthermia treatments on isolated perfused bovine tongues were compared with simulations by a treatment planning system to test whether the discrete vessel model used for the treatment planning is able to predict correct generic temperature distributions.