Yuan D Y, Valvano J W, Anderson G T
University of Texas Austin 78712.
Biomed Sci Instrum. 1993;29:435-42.
This paper describes an experiment technique for the measurement of thermal conductivity, thermal diffusivity and perfusion using self-heated thermistors. Thermal probes are constructed by placing a miniature thermistor at the tip of a plastic catheter. The volume of tissue over which the measurement occurs depends on the surface area of contact between the thermistor and the tissue. Electrical power is delivered to a spherical thermistor positioned invasively within the tissue of interest. The electrical power and resulting temperature rise are measured by a microcomputer-based instrument. When the tissue is perfused by blood, the thermistor heat is removed both by conduction and by heat transfer due to blood flow near the probe. In vivo, the instrument measures effective thermal properties which are the combination of conductive and convective heat transfer. The accuracy of the conductivity and diffusivity measurements was evaluated by operation of the probe in media of known thermal properties. Perfusion measurements in canine liver, prostate, and spleen are presented.
本文描述了一种使用自热式热敏电阻测量热导率、热扩散率和灌注的实验技术。热探头是通过将一个微型热敏电阻放置在塑料导管的尖端构建而成。测量所涉及的组织体积取决于热敏电阻与组织之间的接触表面积。电能被输送到侵入性地置于感兴趣组织内的球形热敏电阻。电能和由此产生的温度上升由基于微型计算机的仪器测量。当组织被血液灌注时，热敏电阻的热量通过传导以及由于探头附近血液流动的热传递而被带走。在体内，该仪器测量的有效热特性是传导性和对流性热传递的组合。通过在已知热特性的介质中操作探头来评估电导率和扩散率测量的准确性。文中给出了在犬类肝脏、前列腺和脾脏中的灌注测量结果。
