The influence of bloodflow in large vessels on the temperature distribution in hyperthermia

1982 ◽  
Vol 27 (1) ◽  
pp. 17-23 ◽  
Author(s):  
J J W Lagendijk
Author(s):  
Hongwei Shao ◽  
Ying He ◽  
Lizhong Mu

In the present study, a simulation has been developed to investigate the blood and temperature distribution in the human hand. The simulation consists of image-based mesh generation, blood flow modeling in large vessels, and finite element analysis of heat transfer in tissues based on the porous media theory. In order to reconstruct a real geometric mesh model of the human hand, sequential MR images of a volunteer’s hand was taken firstly. Furthermore, a MATLAB program was developed to detect the edge information of the target by applying several image preprocessing operators. Finally, a FORTRAN program based on the transfinite interpolation method was developed to generate mesh from the preprocessed images automatically, and the positions of simplified bones and vessels were set according to the anatomic structure. The blood flow in large vessels adopted in this study was provided from the one-dimensional simulation of blood circulation in the upper limb, which was completed by He [1]. On the other hand, blood flow perfused in solid tissues through the micro vessels was expressed by Darcy model. The heat transfer in tissues was described by the energy equation for porous media with assuming that a local equilibrium was achieved between the blood and tissue phase. The primary results for the distribution of the blood flow perfused in tissues and temperature were obtained in this study, and they were similar to the real state of the human hand. The improvement of this simulation will be the next work.


Author(s):  
Zhong-Shan Deng ◽  
Jing Liu

Recently, nano-cryosurgery was proposed to improve freezing efficiency of the conventional cryosurgery. As is well known, the effect of thermally significant large blood vessel on temperature has long been a research focus for conventional cryosurgery, since the warm blood flowing through large vessel may result in insufficient freezing and tumor residual. However, there is little information concerning the effects of large vessels on the temperature distribution and freezing lesion in nano-cryosurgery. In this study, two typical vascular models were applied to investigate the effects of large blood vessels to the thermal distribution and freezing lesion during nano-cryosurgery. The numerical results indicated that, after localized introduction of nanoparticles, large vessels embedding in tumor tissues can be totally frozen during cryosurgery and thus the insufficient freezing region surrounding large vessels can be effectively eliminated. The results also suggested that adjuvant use of nanoparticles is expected to serve as a promising method to tackle the deficiency in conventional freezing of tumors with large blood vessels in future oncological clinics.


2001 ◽  
Vol 123 (5) ◽  
pp. 500-505 ◽  
Author(s):  
Oana I. Craciunescu ◽  
Scott T. Clegg

The effect of blood velocity pulsations on bioheat transfer is studied. A simple model of a straight rigid blood vessel with unsteady periodic flow is considered. A numerical solution that considers the fully coupled Navier–Stokes and energy equations is used for the simulations. The influence of the pulsation rate on the temperature distribution and energy transport is studied for four typical vessel sizes: aorta, large arteries, terminal arterial branches, and arterioles. The results show that: the pulsating axial velocity produces a pulsating temperature distribution; reversal of flow occurs in the aorta and in large vessels, which produces significant time variation in the temperature profile. Change of the pulsation rate yields a change of the energy transport between the vessel wall and fluid for the large vessels. For the thermally important terminal arteries (0.04–1 mm), velocity pulsations have a small influence on temperature distribution and on the energy transport out of the vessels (8 percent for the Womersley number corresponding to a normal heart rate). Given that there is a small difference between the time-averaged unsteady heat fiux due to a pulsating blood velocity and an assumed nonpulsating blood velocity, it is reasonable to assume a nonpulsating blood velocity for the purposes of estimating bioheat transfer.


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