Ultrasound waveguiding of light deep into scattering media

总体而言，光学技术在成像和治疗等生物医学应用中具有吸引力。然而，光在生物组织中的大量散射阻止了超过几毫米深的光有效地穿透到组织中，从而极大地限制了光在生物医学应用中的潜力。因此，迫切需要寻找抑制或绕过散射的方法。在这些概念中，利用超声波通过声光效应改变光路似乎特别有希望。因此，本项目的目的是系统地评估超声波导如何促进光传输到散射组织的深处，从而使生物医学组织的光学和光声成像能够随着穿透深度的增加而增加。在前期研究的基础上，我们建立了超声和光在散射介质中传播的数值模型，以及超声介导光波导的数值模型。利用这些模型，我们得到了实验构型的最佳设置。因此，这些设置将被实施，并使用散射模体和解决方案进行系统的实验分析。最后，我们将优化的概念与光声成像相结合，发展了超声引导光导在更大穿透深度下的光声成像概念。总而言之，我们有两个主要目标：1.全面了解散射介质中超声诱导光波导的物理效应2.在光声成像中通过超声诱导光波导演示高穿透深度

In general, optical technologies are attractive for biomedical applications such as imaging and treatment. However, the massive scattering of light in biological tissue prevents an efficient penetration of light deeper than a few millimeters into the tissue and thus dramatically limits the potential of light for biomedical applications. Therefore, approaches to suppress or circumvent the scattering are desperately sought for. Among those concepts, the use of ultrasound for alteration of the light path via the acoustooptical effect seems particularly promising. Therefore, the aim of this project is to evaluate systematically how ultrasound waveguiding can promote light delivery deep into scattering tissue and by that enable optical and photoacoustic imaging of biomedical tissue with increased penetration depth. Based on our preliminary studies, we develop numerical models for ultrasound and light propagation in scattering media as well as for the ultrasound mediated light waveguiding. With those models, we derive optimum settings for experimental configurations. Consequently, these settings will be implemented and systematically experimentally analyzed with scattering phantoms and solutions. Finally, we combine the optimized concept with photoacoustic imaging and develop concepts for photoacoustic imaging at larger penetration depth due to ultrasound mediated light guiding. In summary, we have two main goals: 1. A comprehensive understanding of the physical effects underlying the ultrasound induced light waveguiding in scattering media 2. Demonstration of high penetration depth via ultrasound induced waveguiding in photoacoustic imaing