Bio-heat transfer analysis during short pulse laser irradiation of tissues
Bio-heat transfer analysis during short pulse laser irradiation of tissues
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DOI：
10.1016/j.ijheatmasstransfer.2008.04.033
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发表时间：
2008-11-01
影响因子：
5.2
通讯作者：
Guo, Zhixiong
中科院分区：
文献类型：
--
作者：
Jaunich, Megan;Raje, Shreya;Guo, Zhixiong
本文分析了短脉冲激光束在准直和聚焦两种情况下，皮肤组织介质中的温度分布和热影响区。实验是在模拟皮肤组织的多层组织模型上进行的，其中嵌入的不均匀性模拟皮下肿瘤，以及新鲜切除的小鼠皮肤组织样品。在本研究中使用了两种类型的激光器，即脉冲宽度为200 ns的Q开关脉冲1064 nm Nd：YAG短脉冲激光器和脉冲宽度为1.3 ps的1552 nm二极管短脉冲激光器。组织介质中的轴向和径向温度分布的实验测量值与数值模拟结果进行了比较。对于数值建模，首先使用离散坐标方法求解瞬态辐射传输方程，以获得组织介质内的强度分布和辐射热通量。然后将生物传热方程与双曲型非傅立叶或抛物线型傅立叶热传导模型耦合，得到温度分布。双曲型热传导方程采用带误差项修正的MacCormack格式求解。实验测得的温度分布与双曲线导热模型预测的温度分布吻合较好。实验测量表明，与相同激光参数的准直激光束相比，直接聚焦在亚表面位置的会聚激光束可以在该位置产生期望的高温。最后，使用组织学研究作为激光参数的函数来表征消融的组织去除。(C)2008爱思唯尔有限公司保留所有权利。
The objective of this paper is to analyze the temperature distributions and heat affected zone in skin tissue medium when irradiated with either a collimated or a focused laser beam from a short pulse laser source. Experiments are performed on multi-layer tissue phantoms simulating skin tissue with embedded inhomogeneities simulating subsurface tumors and as well as on freshly excised mouse skin tissue samples. Two types of lasers have been used in this study - namely a Q-switched pulsed 1064 nm Nd:YAG short pulse laser having a pulse width of 200 ns and a 1552 nm diode short pulsed laser having a pulse width of 1.3 ps. Experimental measurements of axial and radial temperature distribution in the tissue medium are compared with the numerical modeling results. For numerical modeling, the transient radiative transport equation is first solved using a discrete ordinates method for obtaining the intensity distribution and radiative heat flux inside the tissue medium. Then the temperature distribution is obtained by coupling the bio-heat transfer equation with either hyperbolic non-Fourier or parabolic Fourier heat conduction model. The hyperbolic heat conduction equation is solved using MacCormack's scheme with error terms correction. It is observed that experimentally measured temperature distribution is in good agreement with that predicted by hyperbolic heat conduction model. The experimental measurements demonstrate that converging laser beam focused directly at the subsurface location can produce desired high temperature at that location compared to that produced by collimated laser beam for the same laser parameters. Finally the ablated tissue removal is characterized using histological studies as a function of laser parameters. (C) 2008 Elsevier Ltd. All rights reserved.