光学相干断层成像(OCT)技术因非入侵、非接触特点和断层成像能力,在眼科、血管内窥等临床医学与药物学中有广泛应用。OCT发展至今,根据成像方向的优先次序,产生了两类技术分支。一类是沿光束入射方向逐线(A-line)扫描的标准型OCT,可生成基于纵向断面扫描(B scan)的图像,常用于眼底组织的层析成像;另一类en-face OCT,也叫正向切片OCT,可在与入射光垂直的方向上生成样品层的横向切片图像,且以显微成像方式来显示生物组织的精细结构,大大丰富了OCT的图像采集与呈现方式。en-face OCT系统可采用不同的信号采集方式,在对其分析和归纳的基础上,对该技术的主要发展方向作了展望。

The optical coherence tomography (OCT) technology has been extensively used in clinical medicine, (including ophthalmology, intravascular endoscopy) and pharmacology, because of its non-invasive and non-contact features. Until now, OCT can be categorized into two major types according to the priority of imaging direction. One is the standard OCT which can perform A-line scanning along the incident direction of sample beam and has the ability to generate the longitudinal section (B scan) image, normally used to identify the individual retinal layers. The other is the en-face OCT (also called frontal section OCT) which can generate the transverse section image of sample layer in the direction perpendicular to the incident light. Using en-face OCT, the fine structure of the biological sample can be displayed in a field-of-view similar to that of the microscope, considerably extending the acquisition and representation modes of OCT imaging. Different signal acquisition methods can be adopted by en-face OCT systems. A detailed analysis and summary regarding these methods as well as the developing roadmap of en-face OCT are provided.