Multiple scattering of ultrasound in weakly inhomogeneous media: Application to human soft tissues
Multiple scattering of ultrasound in weakly inhomogeneous media: Application to human soft tissues
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DOI：
10.1121/1.3506343
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发表时间：
2011-01-01
影响因子：
2.4
通讯作者：
Derode, Arnaud
中科院分区：
文献类型：
--
作者：
Aubry, Alexandre;Derode, Arnaud
弱非均匀随机介质的散射波包含主要的单次散射贡献以及通常被忽略的多次散射贡献，特别是对于成像目的。提出了一种基于随机矩阵理论的方法来分离单次散射和多次散射的贡献。实验装置使用放置在介质前面的源/接收器阵列。测量每对换能器之间的冲激响应，并形成一个矩阵。单散射的贡献显示出一个确定性的一致性沿着阵列响应矩阵的反对角线，无论分布的不均匀性。利用这一特性来区分单散射波和多散射波。这允许一个评估的吸收损失和散射损失分开，通过比较的多次散射强度与辐射传输模型。此外，可以估计的相对贡献的多次散射的后向散射波，这作为一个有效性测试的玻恩近似。实验结果与超声波在兆赫范围内，在合成样品（琼脂-明胶凝胶）以及乳房组织。有趣的是，在4.3 MHz左右的乳房中，发现多重散射的贡献远非可以忽略不计。(C)2011年美国声学学会。[DOI 10.1121/1.3506343]
Waves scattered by a weakly inhomogeneous random medium contain a predominant single-scattering contribution as well as a multiple-scattering contribution which is usually neglected, especially for imaging purposes. A method based on random matrix theory is proposed to separate the single- and multiple-scattering contributions. The experimental setup uses an array of sources/receivers placed in front of the medium. The impulse responses between every couple of transducers are measured and form a matrix. Single-scattering contributions are shown to exhibit a deterministic coherence along the antidiagonals of the array response matrix, whatever the distribution of inhomogeneities. This property is taken advantage of to discriminate single- from multiple-scattered waves. This allows one to evaluate the absorption losses and the scattering losses separately, by comparing the multiple-scattering intensity with a radiative transfer model. Moreover, the relative contribution of multiple scattering in the backscattered wave can be estimated, which serves as a validity test for the Born approximation. Experimental results are presented with ultrasonic waves in the megahertz range, on a synthetic sample (agar-gelatine gel) as well as on breast tissues. Interestingly, the multiple-scattering contribution is found to be far from negligible in the breast around 4.3 MHz. (C) 2011 Acoustical Society of America. [DOI: 10.1121/1.3506343]