光学相干断层扫描（optical coherence tomography）
光学相干层析技术（Optical Coherence Tomography, OCT）是近十年迅速发展起来的一种成像技术，它利用弱相干光干涉仪的基本原理，检测生物组织不同深度层面对入射弱相干光的背向反射或几次散射信号，通过 扫描，可得到生物组织二维或三维结构图像。
OCT利用宽带光源的短程相干特性对活体组织内部结构断层成像。OCT系统一般由低相干光源(SLD或超快激光器)和迈克尔逊光纤干涉仪组成。OCT是结合了空间门、相干门及其他形式的门技术。目前OCT可探测深度由几个毫米到厘米量级，空间分辨率达到2~20mm。
OCT原理类似于超声成像，只是用光波代替了声波。由于光波波长很短，因而分辨率高，而且成像时不需接触样品。
光 学相干CT（Optical Coherence Tomography），简称OCT，中文全称为“光学相干层析”，是继X射线CT、MRI、超声诊断技术之后的又一种新的医学层析成像方法。它集半导体 激光技术、光学技术、超灵敏探测技术和计算机图像处理技术于一身，能够对人体、生物体进行无伤害的活体检测，获得生物组织内部微观结构的高分辨截面图像。
Optical coherence tomography (OCT) is a light-based imaging modality that can be used in biological systems to study tissues in vivo with near-histologic, ultrahigh resolution. The rationale for intravascular application of OCT is its potential for in vivo visualisation of the coronary artery microstructure.
We have designed a multimodality system that combines optical coherence tomography OCT[1] and laser-induced fluorescence LIF[1] in a 2.0-mm-diameter endoscopic package. OCT provides
18-
m resolution cross-sectional structural information over a 6-mm field.
Here we demonstrate three-dimensional optical coherence tomography (3D OCT) at video rate.
OCT provides high spatial resolution (5–10 mm) images of optical backscattering due to local variations in refractive index, such as the boundary between liquid and frozen water in tissue.
This report reviews the technology of OCT with emphasis on endoscopic applications.
By measuring backscattered light as a function of depth, OCT fills a valuable niche in imaging of tissue microstructure, providing subsurface imaging with high spatial resolution (on the order of ten micrometers) in three dimensions and high sensitivity in vivo with no contact needed between the probe and the tissue.
In this paper, we briefly and selectively review the current state-of-the-art in the more prominent areas of activity in the technology and its application.
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