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In-Vivo Measurement of Thermal Diffusivity of Living Subcutaneous Tissue

活体皮下组织热扩散率的体内测量

基本信息

批准号：
03452133
负责人：
FUJII Motoo
金额：
$ 4.29万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452133/
关键词：
Thermophysical Properties of Organism Non-Contact Measurement In Vivo Measurement Thermal Conductivity Thermal Diffusivity Anisotropic Solid Porous Medium

项目摘要

In the academic year 1991, the principle of the measurement and its accuracy had been examined theoretically at first, then the thermal conductivity and diffusivity were measured for the solid materials with known thermophysical properties similar to those biological tissues and organs. From these measurements, the problems existing in the method had been clarified. In the academic year 1992, three dimensional temperature distributions in a solid were obtained numerically, then some new methods were proposed and their accuracy and applicability for the anisotropic materials were examined. Further, the measurements had been done to obtain thermal conductivity and diffusivity of the subcutaneous tissues of the brachium and the back of the hand. The main achievements of the project are concluded as follows:1. Two-dimensional symmetric heat conduction equation was solved numerically under the boundary conditions of local heating, and convection and radiation heat losses on the surface. Whe … More n the non-dimensional temperature is defined by using the average net heat flux over the heating area, an unique relation between the non-dimensional temperature and Fourier number can be obtained which is independent of these heat losses. This relation can be used to evaluate the thermal conductivity and diffusivity simultaneously.2. It is found that the present method could obtain the thermal conductivity and diffusivity of non-metal solids within an error of 10%, when the errors of heat flux and heating radius are estimated within 5% and 3%, respectively. With the help of measured results of such materials as Acryl and Chloride Vinyl plates, the reflective fraction of laser power has been estimated accurately. When the heat flux is corrected, the errors of thermal conductivity and diffusivity can be further reduced to 2-5%.3. Three-dimensional bioheat transfer equation was analyzed numerically. The effects of the anisotropic characteristic, perfusion and metabolic rate on the surface temperature distributions have been clarified.4. To improve the accuracy of measurement and to apply the method for anisotropic materials, multi-points values of the temperature-time response of the heated surface were used, and some new expanded methods have been proposed. The availability of these methods have been examined.5. The temperature-time responses of the heated surfaces of the brachium and the back of the hand have been recorded under both normal and hemostasis conditions. The effects of the perfusion and metabolic rate on thermal conductivity and diffusivity of subcutaneous tissues have now been examining based on the above new methods. Less

在1991学年，首先从理论上验证了该测量方法的原理和准确性，然后对已知热物理性质的与生物组织和器官相似的固体材料进行了热导率和扩散率的测量。通过这些测量，阐明了该方法存在的问题。在1992学年，数值计算了固体中的三维温度分布，然后提出了一些新的方法，并检验了它们的精度和对各向异性材料的适用性。此外，测量已经完成，以获得肱和手背的皮下组织的热导率和扩散率。本课题取得的主要成果如下：1.在考虑局部加热、表面对流和辐射热损失的边界条件下，对二维对称热传导方程进行数值求解。Whe ...更多信息在无因次温度是由加热区域上的平均净热通量定义的情况下，可以获得无因次温度与傅立叶数之间的唯一关系，该关系与这些热损失无关。该关系式可用于导热系数和扩散系数的精确计算.结果表明，当热流密度和加热半径的误差分别控制在5%和3%以内时，该方法可以在10%以内得到非金属固体的导热系数和扩散系数。借助对丙烯基和氯乙烯基等材料的测量结果，对激光功率的反射率进行了准确的估算。通过热流修正，导热系数和扩散系数的误差可进一步减小到2- 5%.对三维生物传热方程进行了数值分析。阐明了各向异性特性、灌注和代谢速率对表面温度分布的影响.为了提高测量精度，使该方法适用于各向异性材料，采用了多点测量受热面温度-时间响应的方法，并提出了一些新的扩展方法。这些方法的可用性已被检查。在正常和止血条件下，记录了肱动脉和手背加热表面的温度-时间响应。基于上述新方法，研究了灌注和代谢速率对皮下组织导热系数和扩散系数的影响。少