Optical Fiber Grating Characterization for Haptic Sensors in Minimally Invasive Diagnostics and Surgery

在美国，平均每天有30名女性死于卵巢癌，80名男性死于前列腺癌。黑人男性的前列腺癌发病率比白人男性高55%。与这些癌症作斗争的一个主要障碍是确凿的早期发现。微创诊断为这一问题提供了一种潜在的解决方案。然而，如果没有对相关身体区域的感觉(触觉)，医疗专业人员就不能做出完全知情的诊断。与传统技术相比，这在某些情况下会导致更低的疗效和更大的危险。为了克服这一缺陷，光纤光栅可能被用作触觉反馈传感器，以提供微创手术中原本缺失的感觉。然而，由于缺乏关于所需详细设计的明确信息，以及如何测量和验证所需制造已经实现，这一前景看好的方法正受到阻碍。到目前为止，制造这些传感器的方法本质上是非常初级的。这项研究项目在定量测量光纤光栅的物理特性并将其与所需的触觉传感能力相关联方面迈出了重要的一步。这项研究旨在扩大微创手术的安全性和有效性。此外，这项研究还带来了显著的额外红利。也就是说，如果根据诊断结果表明这些手术是可行的，那么本方法也可以用于后续的外科手术。总体而言，这项研究的目的是在对光纤光栅及其在医疗实践中作为触觉传感器的定量使用的定量理解的基础上，制定更准确的诊断程序。这项研究项目包括了许多女性和少数民族学生。即，1)与艾格尼斯·斯科特学院(女子学院)合作的项目，提供微制造和定量相位成像方面的研究经验；2)NSF资助的夏季本科生工程/科学研究(SURE)项目，该项目为少数族裔提供在线期刊和图书馆数据库、参考管理软件以及成功的定量相位成像研究方法。对这些癌症进行更有效的诊断显然会使其他癌症和医疗条件的技术得到改进。微创诊断为这一问题提供了一种潜在的解决方案。然而，这些诊断技术在很大程度上缺乏医疗专业人员的感觉(触觉)。光纤光栅传感器可以潜在地提供所需的触觉反馈。然而，目前还不知道需要进行哪些详细的光纤光栅设计，以及如何对所制作的结构进行定量的测量和验证。为了解决这一不足，本研究项目的目标是应用定量相位成像(QPI)来开发同时表征光纤光栅中折射率分布和残余应力分布的方法。在这项研究项目中开发的新方法是层析反卷积相位显微镜(TDPM)方法的扩展，该方法是在佐治亚理工学院构思并首次实施的。待处理的光纤结构包括1)单光纤中的单光栅，2)多组合光纤中的多光栅，以及3)多芯光纤中的多光栅。这些测量代表了第一次在所提出的高精度和高空间分辨率下同时确定横截面折射率和应力分布。由不同工艺形成的光纤布拉格光栅(FBG)和长周期光纤光栅(LPFG)正在进一步分析中，以深入了解制造工艺对这些作为触觉反馈传感器的光栅性能的影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Each day in the United States, on average, 30 women die of ovarian cancer and 80 men of prostate cancer. There is a 55% greater incidence of prostate cancer in black men than in white men. A major obstacle in the fight against these cancers is conclusive early detection. Minimally invasive diagnostics provide a potential solution to this problem. However, without a sense of feel (haptic) of the relevant bodily region, the medical professional cannot make a complete informed diagnosis. This leads to lower efficacy and increased danger in some cases when compared to traditional techniques. To overcome this deficiency, fiber gratings can potentially be used as haptic feedback sensors to provide the otherwise missing sense of feeling in minimally invasive procedures. However, this promising approach is being stymied by a lack of clear information on the detailed designs needed and how to measure and verify quantitatively that the required fabrication has been achieved. Until the present, the approach to fabricate these sensors has been very rudimentary in nature. This research project takes a major step in quantitatively measuring the physical characteristics of fiber gratings and then correlating them with the needed haptic sensing capabilities. This research is directed toward expanding the safety and efficacy of minimally invasive procedures. Further, there is a significant additional dividend coming from this research. Namely, the present methodology could also be used in subsequent surgical procedures if such procedures are indicated based on the diagnostic results. Overall, this research is directed toward more accurate diagnostic procedures based on a quantitative understanding of fiber gratings and their quantitative use as haptic sensors in medical practice. This research project incorporates numerous female and minority students. Namely, 1) a program with Agnes Scott College (women's college) to provide research experiences in micro-fabrication and quantitative phase imaging,2) the NSF-funded Summer Undergraduate Research in Engineering/Science (SURE) program that gives minorities exposure to on-line journals and library databases, reference management software, and successful research approaches in quantitative phase imaging.TechnicalOvarian and prostate cancers are challenging to diagnose at their early stages. More effective diagnosis for these cancers would obviously enable improved techniques for other cancers and medical conditions as well. Minimally invasive diagnostics provide a potential solution for this problem. However, these diagnostic techniques largely lack a sense of feel (haptic) for the medical professional. Fiber optic grating sensors can potentially provide the needed haptic feedback. However, at the present time, it is not known what detailed fiber grating designs are needed and how to measure and verify quantitatively the fabricated structures. In order to address this deficiency, the goal of this research project is to apply quantitative phase imaging (QPI) to develop methodologies that will characterize concurrently the refractive index distributions and residual stress distributions in fiber gratings. The new methods being developed in this research project are extensions of the tomographic deconvolution phase microscopy (TDPM) approach conceived and first implemented at Georgia Tech. Fiber configurations to be treated include 1) single gratings in single fibers, 2) multiple gratings in multiple combined fibers, and 3) multiple gratings in multi-core fibers. These measurements represent the first concurrent determination of the cross-sectional refractive-index and stress distributions at the proposed high level of accuracy and high spatial resolution. The fiber Bragg gratings (FBGs) and long-period fiber gratings (LPFGs) formed by various processes are further being analyzed to provide insights into the effects of fabrication on the performance of these gratings as a haptic feedback sensors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.