This work concerns the development and testing of a setup that uses laser-induced ultrasound sources to achieve synthetic transmit aperture ultrasound imaging. The sources are created by sequentially firing 32 contiguous multi-mode optical fibers to illuminate an optically absorbing film with nanosecond-pulsed laser light. Ultrasound is generated by the photoacoustic effect and insonifies the sample under investigation. Ultrasound that has interacted with the sample is detected in reflection mode using a conventional ultrasound transducer array. We present a custom-developed optical fiber multiplexing setup that enables sequential firing of the optical fiber array and characterize the acoustic fields produced by the laser-induced approach using hydrophone measurements. The integrated setup is used to make images of wire phantoms. Following this, images are taken of a breast-mimicking phantom as well as the wrist of one of the authors. Imaging results from the new approach and from conventional ultrasound imaging are compared. The lateral and axial point-spread function values show broad agreement between the two approaches, whereas the phantom and in vivo images exhibit some differences in contrast values. This work is, to our knowledge, the first instance of laser-induced ultrasound synthetic transmit aperture imaging using a clinical ultrasound array.

中文翻译：

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激光诱导合成孔径超声成像

这项工作涉及使用激光诱导超声源实现合成发射孔径超声成像的装置的开发和测试。这些光源是通过连续发射 32 根连续的多模光纤以用纳秒脉冲激光照射光吸收膜而产生的。超声波是由光声效应产生的，并对所研究的样品进行声波处理。使用传统的超声换能器阵列以反射模式检测与样品相互作用的超声。我们提出了一种定制开发的光纤多路复用设置，它能够连续发射光纤阵列，并使用水听器测量来表征由激光诱导方法产生的声场。集成设置用于制作线体模型的图像。按照此，图像取自一个模仿乳房的幻影以及作者之一的手腕。比较了新方法和传统超声成像的成像结果。横向和轴向点扩展函数值显示两种方法之间的广泛一致性，而体模和体内图像在对比度值方面表现出一些差异。据我们所知，这项工作是使用临床超声阵列的激光诱导超声合成发射孔径成像的第一个实例。而体模和活体图像在对比度值方面表现出一些差异。据我们所知，这项工作是使用临床超声阵列的激光诱导超声合成发射孔径成像的第一个实例。而体模和活体图像在对比度值方面表现出一些差异。据我们所知，这项工作是使用临床超声阵列的激光诱导超声合成发射孔径成像的第一个实例。