一种测量生物组织热导率的新方法

采用脉冲衰减法可以测量生物组织热导率。但是,Chen等人提出的脉冲衰减法采用了“点热源”假设,而实际测量时,探头有一定的几何尺寸,由此造成了测量时的模型误差。本文采用数值实验的方法对这一误差及其影响因素进行了分析。在此基础上,提出了一种考虑了探头尺寸影响的新的脉冲衰减法,推导出了其测量公式。采用已知热导率的工质进行了验证试验,实验测量结果证实了本文对原有测量方法误差的分析;同时也表明,采用本文提出方法可以将测量误差减小到5%以下。

A NOVEL MODEL FOR MEASUREMENT OF TISSUE THERMAL CONDUCTIVITY

The existing thermal pulse-decay method presented by Chen et al can be used to measure the thermal conductivity of bio-tissue, in which the probe bead was assumed to be a heating point source. However, the actual size of the probe bead is finite. Therefore, this assumption would induce a model error in the measurement result. In this paper, a numerical experiment method is used to analyses the model error; and a novel model of the thermal pulse-decay method is presented, in which the effects of the size of the probe bead are considered. The corresponding measurement formula is also developed. To test the accuracy of the thermal conductivity measured by using the two methods, five liquid standards whose thermal conductivities are already known are used. The experiment results prove our analysis for the model error of the existing thermal pulse-decay method. Moreover, the experiment results show that the measurement error can be reduced to smaller than 5% by using the novel model.