WAVEFRONT SHAPING FOR IMPROVED IMAGING CONTRAST IN OPTICAL COHERENCE TOMOGRAPHY

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 组织是一种不均匀的混浊介质，这会导致通过它传播的光的多次散射;因此，光在几个平均自由路径的传输距离上变得漫射。 在可见光和近红外区，一个平均自由程约为100 μ m。因此，入射波前可以有效地聚焦在组织样本内的深度是有限的。因此，光的多次散射降低了对比度，从而降低了成像深度，例如在共焦显微镜、多光子显微镜和光学相干断层扫描的情况下。此外，由于多重散射引起的光漫射也限制了基于光的治疗方式（诸如光动力疗法）的深度范围和有效性。然而，弹性散射效应是确定性的和可逆的。本研究的目标是开发有效的方法来适当地塑造照明波场，使光既能穿透样品内部深处，又能集中在感兴趣的区域，以改善当前的成像和治疗方式。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Tissue is a heterogeneous, turbid medium, which causes multiple scattering of a light propagating through it; thus the light becomes diffused over transmission distances of a few mean-free paths. In visible and near infrared regime, one mean-free path is on the order of 100 ¿m. Thus, the depth at which an incident wavefront can be effectively focused within a tissue sample is limited. Multiple scattering of light therefore reduces the contrast and hence the imaging depth such as in case of confocal microscopy, multiphoton microscopy, and optical coherence tomography. In addition, light diffusion due to multiple scattering also limits the depth range and effectiveness of light-based therapeutic modalities such as photodynamic therapy. However, elastic-scattering effects are deterministic and reversible. The goal of this study is to develop efficient ways to appropriately shape the illumination wavefield so that the light both penetrates deep within the sample and is concentrated at a region of interest in order to improve current imaging and therapeutic modalities.