测量生物组织血液灌注率的ATM模型及其误差分析

Sensitivity Analysis of the Average Temperature Model for Measurement of Local Tissue Blood Perfusion

采用脉冲衰减法可以测量生物组织的血液灌注率。本研究给出了脉冲衰减法测量时探头平均温度的理论解(ATM模型)。通过分析温度测量误差及探头输入功率测量误差引起的血液灌注率测量误差,以及测量时的模型误差,比较了ATM模型与现有的PSM模型(Point Source Model)及SSM模型(Spherical Source Model)的测量精度。结果表明,对三种模型,由温度测量误差及探头输入功率测量误差引起的血液灌注率测量误差均大致相等;而采用ATM模型测量时的模型误差比PSM模型和SSM模型要小;测量时刻以脉冲后13s^17s为宜;测量时应尽量选用几何尺寸比较小的生物探头;对于小血液灌注的测量,采用ATM模型更为有利。

The thermal pulse-decay method can be used to measure blood perfusion of bio-tissue. The probe bead average temperature analytical solution（ATM：average temperature model）was presented based on the method in this paper. By analyzing the blood perfusion error caused by error in measured temperature, the blood perfusion error caused by error in measured supplied power, and the blood perfusion model error, the measuring accuracy of the ATM and the existing point source model （PSM） and spherical source model（SSM） were compared. The results showed that, the blood perfusion error caused by error in measured temperature and the blood perfusion error caused by error in measured supplied power were almost equal for the above-mentioned three models. In all the cases tested in this paper, the model error of ATM model was smeller than that of the point source model and spherical source model. The optimal measurement time was determined as 13 - 17 seconds after the pulse. It was suggested to select probe bead with small size to measure blood perfusion in bio-tissue. And the ATM modcl was more suitable for the measurement of low level blood perlusion.