Ultrasound computed tomography (USCT) is a noninvasive imaging modality that has shown its clinical relevance for breast cancer diagnostics. As opposed to traveltime inversions, waveform-based inversions can exploit the full content of ultrasound data, thereby providing increased resolution. However, this is only feasible when modeling the full physics of wave propagation, accounting for 3D effects such as refraction and diffraction, and this comes at a significant computational cost. To mitigate this cost, a crosstalk-free source encoding method for explicit time-domain solvers is proposed. The gradient computation is performed with only two numerical “super” wave simulations, independent of the number of sources and receivers. Absence of crosstalk is achieved by considering orthogonal frequencies attributed to each source. By considering “double-difference” measurements, no a priori knowledge of the source time function is required. With this method, full-physics based 3D waveform inversions can be performed within minutes using reasonable computational resources, fitting clinical requirements.

中文翻译：

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粘声超声计算机断层扫描的源编码。

超声计算机断层扫描（USCT）是一种无创成像手段，已显示出其对乳腺癌诊断的临床意义。与行程时间反演相反，基于波形的反演可以利用超声数据的全部内容，从而提供更高的分辨率。但是，这仅在对波传播的完整物理模型进行建模（考虑到折射和衍射之类的3D效应）时才可行，并且这需要大量的计算成本。为了减轻这种成本，提出了一种用于显式时域求解器的无串扰源编码方法。梯度计算仅通过两个数值“超级”波模拟执行，而与源和接收器的数量无关。通过考虑归因于每个信号源的正交频率，可以避免串扰。需要有关源时间功能的先验知识。通过这种方法，可以使用合理的计算资源在几分钟内执行基于全物理的3D波形反演，从而满足临床需求。