Advanced Biophotonic Structured Illumination Imaging System Design

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”结构照明（SI）是新一代的技术之一，最近被证明可以打破显微镜的衍射极限。超分辨率的SI方法包括用空间频率载波照射物体，该载波将物体的高频特征降移到成像系统的光学传递函数内。对于入射照明线性响应的物体，分辨率增加2x是可能的，而对于非线性响应的物体（如荧光或受激发射的饱和），分辨率的提高在理论上是无限的（尽管它与灵敏度相权衡）。将该方法应用于标准台式显微镜，实现了50纳米分辨率的超分辨率成像。以前的SI成像实现使用直接的正弦照明模式，并依赖于确定性相移和不同角度方向的多次曝光来获取超分辨率图像重建所需的完整复k空间数据。在这些参数可控的实验室条件下，这些方法在稳定和表征良好的显微镜下是可行的。SI成像的原理代表了成像科学的基本进步，并在各种生物光子成像应用中具有分辨率提高的潜力，包括人类临床诊断。在被成像对象或成像设备本身的特定特征限制了数值孔径从而限制了可实现的分辨率的情况下，SI成像的优势尤其引人注目。前者的一个例子是人类视网膜的成像，其中解剖虹膜和中心区域以外的眼角膜的光学质量限制了可用的数值孔径。后者的一个例子是内窥镜或导管成像，其中光学器件的物理尺寸与所需的工作距离相结合，严重限制了数值孔径。该项目将启动一项研究计划，研究如何扩展SI成像技术，以满足临床光学仪器对鲁棒性和速度的要求。该项目将重点关注人眼视网膜的超分辨率成像，研究人员在光学相干断层扫描技术的开发方面有相当多的经验。在开发用于临床的结构化照明检眼镜的主题下，首次提出了实现和测试结构化照明线扫描激光检眼镜的原型设计。然后，研究将在从实验室过渡到临床超分辨率成像的预期困难的推动下，对SI技术的三个具体进展进行发展。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."0933059IzattStructured illumination (SI) is one of a new generation of techniques which have recently been demonstrated to break the diffraction limit in microscopy. The SI approach to superresolution involves illuminating the object with a spatial frequency carrier which down-shifts the object's high-frequency features to within the optical transfer function of the imaging system. For objects which respond linearly to the incident illumination, a resolution increase of 2x is possible, whereas for objects which respond nonlinearly (such as saturation of fluorescence or of stimulated emission), the resolution improvement is theoretically unlimited (although it trades off with sensitivity). Applying this methodology as a modification to standard tabletop microscopes, super-resolution imaging with 50nm resolution has been reported. Previous implementations of SI imaging have utilized straightforward sinusoidal illumination patterns, and relied upon deterministic phase shifting and multiple exposures at different angular orientations to acquire the full complex k-space data required for superresolved image reconstruction. These approaches are practical in stable and well-characterized microscopes under laboratory conditions, for which these parameters are controllable. The principles of SI imaging represent a fundamental advance in imaging science, and carry the potential of resolution improvement in a variety of biophotonic imaging applications, including human clinical diagnostics. The advantages of SI imaging are particularly compelling in situations where specific features of either the object to be imaged or of the imaging device itself limit the numerical aperture and therefore the achievable resolution. An example of the former is in imaging of the human retina, where the anatomical iris and the optical quality of the ornea outside of the central zone limit the usable numerical aperture. An example of the latter is in endoscopic or catheter imaging, where the physical size of the optics in combination with the desired working distance conspire to severely limit numerical aperture. The proposed project will initiate a research program to investigate how SI imaging technology can be extended to meet the requirements of robustness and speed required of clinical optical instrumentation. The project will focus on the goal of super-resolved imaging of the human retina in the living human eye, where the investigators have considerable previous experience in the development of optical coherence tomography technology. Under the rubric of developing a structured illumination ophthalmoscope for clinical use, it is first proposed to implement and test a prototype structured illumination line-scanning laser ophthalmolscope design. Then, research will be conducted on the development of three specific advances in SI technology motivated by anticipated difficulties in transitioning from laboratory to clinical superresolution imaging.