基于等温加热法的生物组织热物性参数在位测量系统研究.pdf

南京航空航天大学硕士学位论文 I 摘 要 生物组织热物性参数（导热率、血液灌注率、热扩散率和组织代谢率等）是生物传热模型中的基本参数，它们是揭示生物材料的热传输能力和载热能力以及进一步研究生物传热的基础生物组织热物性参数实时在位测试对生物体传热机制的研究、组织无损温度重构、疾病诊断和肿瘤热疗等领域有着重要的意义 本文研究一套基于等温加热法的局部生物组织热物性参数实时在位测量系统系统包括硬件和软件两个部分，硬件由测量电路和数据采集两部分组成由 NTC 热敏电阻实时采集局部温度信号，PCI-6221 数据采集卡采集数据采用NI 公司 LabVIEW 虚拟仪器平台开发系统软件， 软件能够完成参数输入、 数据采集、显示和存储等功能 论文主要工作与创新点： 1、测试系统的设计与调试系统主要特点：利用虚拟仪器技术进行软件开发；实现了热物性参数实时在位监测,为将来的临床实时监控打下了基础；测量精度高且稳定性好 2、系统定标主要工作有热敏探头参数和测试参数经验公式定标这部分工作确保了测试参数的准确性，通过大量实验得到了本系统的热物性参数计算经验公式，建立了一套完整的参数定标技术，准确的测试结果验证了系统可靠性，这是创新点之一。

3、实时在位测量离体和活体生物组织的热物性参数（导热率、血液灌注率等） 测试了大量离体和活体的实验标本，得到了具有一定参考价值的组织热物性参数，这是本文的重要创新点 关键词：关键词：热物性参数，等温加热法，导热率，血液灌注率，NTC 热敏电阻，虚拟仪器 基于等温加热法的生物组织热物性参数在位测量系统研究 IIABSTRACT The thermophysical parameters of biological tissue ( thermal conductivity, blood perfusion, thermal diffusivity, metabolic heat rate and etc.) are the basic parameters for bio-heat transfer models. They indicate the capabilities of bio-heat transfer and loading, also be the base of in-depth research on bio-heat transfer. The real-time and in vivo measurement of the thermophysical parameters is significant for the research of bio-heat mechanism, non-invasive temperature distribution of tissue, disease diagnosis, tumour thermal therapy and so on. A real-time and in vivo measurement system of thermophysical parameters of local biological tissue based on isothermal heating technology is developed in this paper. This system is composed of hardware and sofeware. The hardware includes measurement circuit and data acquisition system. The NTC thermistor resistance acquires the local temperature, and the PCI-6221 card achieves the conversion of analog and digital signals. The software development is based on LabVIEW which is virtual instrument platform of the National Instrument I, and it is available to realize parameters imput, data acquisition, display and storage. The main work and innovation of this paper is: 1、System design and debugging: The system is developed based on virtual instrument, and it is convenient to update and expand functions. Its function of real-time and in vivo measurement is the base of clinical application. The system has good precision and stability. 2、 System calibration: Including parameters of thermistor resistance and revision expressions of measurement results. This task insured the veracity and reliability of system based on calibration method of using mass experiment data aquired from measurement system. 3、 In vivo and in vitro tissue experiments. The data acquired by the measurement system has great reference value, and also be the base of science research on thermal therapy field and so on. 南京航空航天大学硕士学位论文 III Key Words: thermophysical parameters, isothermal heating technology, thermal conductivity, the blood perfusion, NTC thermistor resistance, virtual instrument 基于等温加热法的生物组织热物性参数在位测量系统研究 VI图清单 图 1.1 平板法测量组织导热率............................................................................3 图 1.2 热方波示意图............................................................................................4 图 2.1 输入功率随时间变化曲线......................................................................15 图 3.1 测量系统原理图（a）测量系统图（b）基础电路图..........................17 图 3.2 热敏电阻伏安特性..................................................................................19 图 3.3 温度渐升、渐降和 Nominal 下阻值变化曲线......................................22 图 3.4 标定曲线与 Nominal 曲线拟合情况......................................................25 图 3.5 探针设计（a）刚性探针（b）柔性探针..............................................26 图 3.6 AA6B4-GC11KA1443L 型热敏电阻..........................................................26 图 3.7 热敏电阻探针实物图..............................................................................27 图 3.8 测量电路原理简图..................................................................................27 图 3.9 电路元件（a）LF353（b）OP07（c）典型接线方式..........................28 图 3.10 电路仿真程序图....................................................................................29 图 4.1 虚拟仪器的硬件构成方式......................................................................31 图 4.2 数据采集应用结构..................................................................................32 图 4.3 信号参考点（a）接地信号（b）浮动信号..........................................34 图 4.4 差分测试系统图......................................................................................35 图 4.5 单端测试系统（a）参考单端测试系统（b）非参考单端测试系统..35 图 4.6 PCI-6221 引脚图....................................................................................36 图 4.7 软件层次结构图......................................................................................39 图 4.8 程序流程图..............................................................................................40 图 4.9 方法一数据通道测试界面......................................................................41 图 4.10 方法二数据输入通道测试前面板........................................................41 图 4.11 方法二数据输入通道测试程序框图....................................................41 图 4.12 方法二数据输出通道测试前面板.......................................。