根据光声理论,建立了血液光声信号的数值计算模型,计算了检测参数(血管的直径、探测距离及探测器相对于血管的偏离程度)对光声信号的影响。分析了这三种参数对脉冲光声法计算绝对吸收系数准确性的影响。数值计算结果表明,探测距离及探测器相对于血管的偏离程度对计算结果的影响可以忽略,而血管的直径对计算结果有较大的影响,忽略血管直径的影响是造成目前脉冲光声法测量绝对吸收系数准确性较低的主要原因,为脉冲光声法的改进提供了依据。

A numerical model for calculating photoacoustic signals from a blood vessel is presented based on the photoacoustic theory. With this model the influences of measurement parameters on photoacoustic signals and the accuracy of measurement of optical absorption coefficient of blood with the fitting-based pulsed photoacoustic method are demonstrated. The computational results indicate that the diameter of the blood vessel has a significant influence on the accuracy of the fitting-based pulsed photoacoustic method and it should be taken into account for improving the accuracy of this method.