活体组织血液灌注率无损测量方法的研究

STUDY ON THE NONINVASIVE MEASUREMENT ON THE BIOLOGICAL BLOOD PERFUSION IN VIVO

活体组织血液灌注率的无损测量是生物医学工程领域中一个十分重要而困难的课题。本文基于新近报道的血液灌注率无损测量方法 ,提出了简化的一次加热测量措施以取代原方法中必须经两次加热的不足 ,从而大大缩短了小灌注率组织的测量时间。由此导出了体表在一次简谐加热作用下组织温度响应的解析解 ,解的形式及随后的计算结果表明了方法的可行性。针对空间非均匀或温度依赖型血液灌注率情形 ,本文采用双倒易边界元方法研究了加热能流密度、简谐热流振幅、加热频率、皮下血管、血液灌注率、加热片面积大小等对组织温度响应幅度、相位等的影响规律 ,由此提出了无损估测非均匀血液灌注率的措施。这些系统性结论为发展适合于临床应用的血液灌注率无损测量仪器建立了相对完整的理论基础。

The noninvasive measurement on the biological blood perfusion has been a critical however difficult problem in the biomedical engineering field. Based on the newly developed phase shift principle, a simplified one step heating to measure the blood perfusion was proposed in this paper to replace the original two step heating method and it can thus significantly reduce the time needed to measure the biological bodies with small perfusion. An analytical solution was obtained to predict the temperature response of the biological bodies subject to the one step sinusoidal heating at the skin surface. The solution form and the calculations show the feasibility of the method. For the space or temperature dependent blood perfusion problems, the dual reciprocity boundary element method (DRBEM) was used to investigate the influences of the heating flux, the heating oscillation magnitude, the heating frequency, the blood vessel underneath the skin, and the blood perfusion etc. To the temperature response and phase shift. And approaches for estimating the non homogeneous blood perfusion were suggested. The paper also examined the effects of the heating area to the temperature response and the approach to design the skin heating plate was proposed. These systematical studies are expected to provide a relatively complete theoretical foundation for