SELF HEATED THERMISTORS TO QUANTIFY TISSUE PERFUSION

本研究的目的是联合收割机数值，分析， 三位研究人员的实验和医学专业知识， 产生一种改进的诊断技术， 传导率、热扩散率和灌注， 自热式热敏电阻探头。 本次研究将有四个主要 努力 第一个任务将使用有限元数值分析， 优化热敏电阻探头设计和测量方案。 第二 任务将是一个详尽的实验错误分析，使用一个孤立的 大鼠肝脏制备。 第三个任务是收集一个 体外热性能数据库。 导热系数和扩散系数 人体活检和尸检组织将被测量。 第四项任务将 是实现现有的微型计算机的临床版本， 仪器 机构审查委员会批准本工具， 表面热敏电阻探头，将被要求，以进行未来的 临床研究。 稳态和正弦热功率的组合被输送到 侵入性地定位在组织内的球形热敏电阻，或 非侵入性地在组织的表面上。 热量被带走 探针通过热传导和灌注进入组织。 有限 采用有限元法数值求解了热传导方程， 加热的热敏电阻和灌注的组织。 述电力和所述 由此产生的温升由微机仪器测量。 这些测量值用于计算有效导热系数 它代表了生物热的传导和对流成分 转移 因为组织血流强烈影响局部热传递， 该仪器对灌注非常敏感。 这项提案的资金将转化为长期的改善 在病人护理中。

The objective of this research is to combine the numerical, analytic, experimental, and medical expertise of the three investigators in order to produce an improved diagnostic technique for measuring thermal conductivity, thermal diffusivity, and perfusion using miniature self-heated thermistor probes. The proposed research will have four major efforts. The first task will use finite element numerical analysis to optimize the thermistor probe design, and measurement protocol. The second task will be an exhaustive experimental error analysis using an isolated rat liver preparation. The third task will be the collection of an in vitro thermal property data base. The thermal conductivity and diffusivity of human biopsy, and autopsy tissue will be measured. The fourth task will be to implement a clinical version of the existing microcomputer based instrument. Institutional Review Board approval of this instrument, with surface thermistor probes, will be requested in order to conduct future clinical studies. A combination of steady state and sinusoidal thermal power is delivered to a spherical thermistor positioned invasively within a tissue or noninvasively on the surface of a tissue. The heat is carried away from the probe into the tissue by thermal conduction, and perfusion. The finite element method is used to numerically solve the heat transfer between the heated thermistor and the perfused tissue. The electrical power and the resulting temperature rise are measured by the microcomputer instrument. These measurements are used to calculate the effective thermal conductivity which represents both the conductive and convective components of bioheat transfer. Because tissue blood flow strongly affects local heat transfer, the instrument is quite sensitive to perfusion. The funding of this proposal will translate into a long lasting improvement in patient care.