基于单焦点扫描的聚焦超声相控阵列波形分集方法

波形分集方法可以用于优化超声相控阵列的声能沉积分布。本文阐述了波形分集方法用于超声热疗的声学理论背景,将发送声波时间内目标区域的声能沉积看作是不同位置的单焦点能量按一定时间规律累积的结果,提出了基于单焦点扫描的波形分集方法。该方法将声能沉积分布的优化问题建模为线性规划问题,可以方便求解出各单焦点扫描时间的比例系数,用于设计发射波形。与已有的方法相比,该方法对应的物理实现过程更清晰,计算量更小,并可直接综合出满足恒模条件的发射波形。从仿真结果中看到,该方法可将声场能量均匀的集中在预定区域,并在该区域外保持较低的能量沉积,能有效优化声能沉积的分布。 

A waveform diversity method based on single focus spot scanning of focused ultrasound phased arrays

Waveform diversity can be used in ultrasound phased array for optimizing acoustic power depositions.The acoustic theory of applying the waveform diversity in ultrasound hyperthermia is addressed.By regarding the acoustic power depositions in the transmitting time as the summation of the power for multiple single foci at different locations integrated via a specific time rule,a waveform diversity method based on single focus spot scanning of ultrasound phased arrays is proposed.Accordingly,the optimization problem that connects the acoustic power depositions is constructed with linear programming.It is convenient to solve the ratios of the dwell time at each focal point and design the transmitted waveform.Compared with the existing method,this method leads to more clearly physical realization process,computation reduction and can directly synthesize the constant-modulus waveforms.Numerical examples are also provided to demonstrate the validity and efficiency of this method.The results show that the acoustic power uniformly focuses onto the predetermined region while maintaining a low level in the surrounding