基于反相位脉冲技术的生物组织谐波成像研究

理论及实验研究了反相位脉冲技术在生物组织二次谐波成像中的应用。结合有限振幅声波的非线性传播理论,从理论上证明了反相位脉冲技术可有效抑制基波信号,同时二次谐波信号增强两倍,轴向及径向声场的实验测量结果基波被抑制30~50dB,二次谐波提高6dB,与理论相符。建立了相应的成像系统,对若干生物离体组织进行了基于反相位脉冲相位技术的二次谐波成像,并与常规的基波及二次谐波图像对比,进一步证明了该技术能有效提高图像的对比度和清晰度。

Investigation on tissue harmonic imaging using phase inversion technique

The application of the phase inversion technique in tissue harmonic imaging is theoretically and experimentally studied in the paper.Based on the nonlinear propagation theory of the finite amplitude sound wave,it is proved that the fundamental frequency component is efficiently suppressed while the second harmonic component is doubled by the use of the phase inversion technique.Measurement of the axial and lateral beam profiles demonstrates that the fundamental frequency component is suppressed by about 30 dB to 50 dB while the second harmonic component is enhanced by 6 dB,which coincides well with the theoretical predication.Experimental system for tissue harmonic imaging with phase inversion technique is setup and images for several biological tissue specimens are obtained.Compared with the traditional fundamental frequency imaging and the second harmonic imaging,the second harmonic imaging with the phase inversion technique can improve the clarity and contrast of image.