Pulsed photoacoustic Doppler flowmetry using time-domain cross-correlation: Accuracy, resolution and scalability
Pulsed photoacoustic Doppler flowmetry using time-domain cross-correlation: Accuracy, resolution and scalability
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DOI：
10.1121/1.4739458
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发表时间：
2012-09-01
影响因子：
2.4
通讯作者：
Beard, Paul
中科院分区：
文献类型：
--
作者：
Brunker, Joanna;Beard, Paul
已经研究了在声分辨率模式下使用脉冲光声多普勒技术进行血速空间分辨测量的可行性。通过使用光脉冲对在血液模拟体模内生成的光声波形对的互相关来量化多普勒时移。该模型由压印在醋酸纤维片上的微米级吸收器组成，并以已知的速度移动。使用中心频率为 20 MHz、5 MHz 和 3.5 MHz 的 PZT 超声换能器检测光声波；速度和分辨率的测量值是根据 25 个波形对的平均互相关函数计算得出的。对 +/- 0.15 至 +/- 1.5 ms(-1) 范围内的速度进行量化，精度低至 1%。换能器焦点光束宽度确定最大可测量速度垂直条V-max垂直条，超过该速度垂直条就会由于吸收体移出两个激光脉冲之间的焦点光束而导致相关性丢失。在垂直条 V-max 垂直条下方，测量分辨率为
The feasibility of making spatially resolved measurements of blood velocity using a pulsed photoacoustic Doppler technique in acoustic resolution mode has been investigated. Doppler time shifts were quantified via cross-correlation of photoacoustic waveform pairs generated within a blood-simulating phantom using pairs of light pulses. The phantom comprised micron-scale absorbers imprinted on an acetate sheet and moved at known velocities. The photoacoustic waves were detected using PZT ultrasound transducers operating at center frequencies of 20 MHz, 5 MHz and 3.5 MHz; measurements of velocity and resolution were calculated from the mean cross-correlation function of 25 waveform pairs. Velocities in the range +/- 0.15 to +/- 1.5 ms(-1) were quantified with accuracies as low as 1%. The transducer focal beam width determines a maximum measurable velocity vertical bar V-max vertical bar beyond which correlation is lost due to absorbers moving out of the focal beam between the two laser pulses. Below vertical bar V-max vertical bar a measurement resolution of