生物声学成像中声速不均匀性解决方法的研究进展

Review on solution to SOS inhomogeneity in biological acoustic imaging techniques

对于以超声波为载体的生物医学声学成像(如超声、光声和磁声成像等)技术,为了简化问题,常在假设待测组织内声速恒定的前提下,重建组织内的声阻抗、光吸收分布、光学特性参数分布或者电导率分布等。但是,实际生物组织内部的声速是存在差异的(最大可达10%),因而在此假设前提下重建出的图像通常是不准确的。在介绍声速不均匀性对声学图像重建影响的基础上,对超声、光声和磁声成像中解决声速不均匀问题的主要方法,特别是光声层析成像中重建组织内声速分布的主要方法进行总结和归纳,讨论各自的优点和不足,并展望未来的可能发展方向。

For the ultrasound based biological imaging techniques, such as ultrasonic imaging, photo acoustic tomography （PAT） and magneto acoustic tomography （MAT）, the spatial distribution of acoustic impedance, light absorption, optical parameters or electrical conductivity in the imaging tissue is always reconstructed under the assumption of a constant speed of sound （SOS） in tissues. However, the actual difference of SOS in different biological tissues may be up to 10%. This paper reviews the current methods to solve the problem of SOS inhomogeneity based on a brief introduction to the influence of SOS inhomogeneity on acoustic image reconstruction. Especially, the methods of restoring the distribution of SOS in the target tissue in PAT are overviewed including their advantages and disadvantages. Possible improvement in the future is also forecasted.