光学相干层析成像焦深拓展方法研究进展

Advances in depth-of-focus extension methods for optical coherence tomography

伴随着光学相干层析成像(OCT)技术的临床应用从眼科拓展至各类人体腔道、功能成像、诊疗一体化、手术机器人等,亟需提升其分辨率以解析细胞及以下尺度的生物组织结构。然而,OCT横向分辨率提升伴随着焦深的下降,难以在整个OCT成像范围内获得较为均一的点扩散函数。针对这一挑战,研究人员提出了多种焦深拓展策略,包括贝塞尔光束、相位掩模、色散效应、合成孔径、计算成像、多模干涉和动态聚焦等。这些方法通过不同的原理实现焦深的扩展,优化OCT成像的深度和质量。详细讨论了这些技术的工作原理、实现方法、优势和局限性,并基于自由空间和内窥OCT两种主要探测形式,比较了各类焦深拓展方法的效果。最后,对OCT焦深拓展技术及应用的未来发展进行了展望,指出了潜在的研究方向和挑战。

With the expansion of clinical applications of Optical Coherence Tomography(OCT)from ophthalmology to various body cavities,functional imaging,diagnostic integration,surgical robotics,etc.,there is an urgent need to improve the resolution of OCT in order to analyze the structure of biological tissues at the cellular scale and below.However,the increase in OCT lateral resolution is accompanied by a decrease in depth of focus,making it difficult to obtain a more homogeneous point spread function across the entire OCT imaging range.To address this challenge,researchers have proposed a variety of depth-of-focus expansion strategies,including Bessel beams,phase masks,dispersion effects,synthetic apertures,computational imaging,multimode interference,and dynamic focusing.These methods realize the depth of focus expansion through different principles to enhance the depth and quality of OCT imaging.In this paper,the working principles,realization methods,advantages and limitations of these techniques are discussed in detail,and the effects of various types of depth-of-focus expansion methods are compared based on the two main detection forms of free-space and endoscopic OCT.Finally,this paper provides an outlook on the future development of OCT depth-of-focus expansion techniques and applications,pointing out potential research directions and challenges.