Integrated 'on-chip' optical coherence tomography (OCT) system for point of care imaging diagnostics

研究背景：尼泊尔被列为发展援助委员会(发援会)名单上收入最低的国家之一，按大多数标准衡量，即使与亚洲其他国家相比，该国人口的总体健康状况也被认为是较差的。获得医疗保健的机会受到严格限制，特别是在农村地区，总的来说，这无疑是取得进展的一个限制因素。我们已经确定了尼泊尔境内未得到满足的特定临床需求，该需求与这项建议的呼吁完全一致；它可以通过提供负担得起的医疗保健点成像诊断而得到帮助。尼泊尔人口中慢性阻塞性肺疾病(COPD)的患病率异常高(高达43%)，这是近年来该国的头号死因(&gt；9%)。这被认为主要是由于室内空气质量差造成的，在地理上和经济上都很难到达的农村地区，这种情况更加严重。目的和目标：我们的目标是开发一种基于光学相干断层扫描(OCT)的低成本、小型化、集成的基于光学相干断层扫描(OCT)的诊断工具，该工具将为COPD诊断和治疗带来变革性的复杂程度的改变。关键的进步将来自于将商业OCT系统核心的基于光纤的干涉仪转移到硅光电子芯片上，这将通过制造可扩展性实现系统复杂性和成本降低。硅光子学非常适合这一点，因为它在大多数OCT系统的目标工作波长(1300 Nm)下是透明的，所需的干涉仪组件现在都已单独演示。利用围绕电信业建立的全球无源制造基础设施，这些亚微米光学设备的制造可以以较低的成本大规模扩展，并达到极高的容差。此外，这些组件中的许多现在也已在氮化硅(SiN)平台上实现，将功能向下扩展到可见光范围，这与某些生物医学成像制度特别相关。我们将通过波长缩放的普通光学电路设计作为概念验证，开发与硅器件并行的基于SIN的干涉仪。最后，我们将迈出雄心勃勃的一步，通过将微型光源与基于硅/氮化硅的干涉仪进行混合集成来开发基于完整、无光纤芯片的解决方案。潜在的应用和优势：将低复杂性、低成本、微型OCT系统整合到现有的支气管镜或导管医疗设备中，可以在移动平台上与商用数据采集硬件和分析软件一起使用，这一愿景已经触手可及。这样的系统可以提供必要的途径，以获得复杂的成像诊断工具，可以取代基本的肺活量测定，甚至纤维支气管镜检查，成为早期诊断COPD的黄金标准。最初将在我们的伙伴国家尼泊尔的偏远地区感受到它的最大好处，在那里，这种疾病的高流行率就是例证，在那里，获得这种设施的机会受到地理和经济的限制。组织成像分辨率和速度的提高也有望从根本上帮助我们更好地了解COPD的进展。例如，拟议的OCT技术的开发和广泛采用将产生高质量的特定人群数据集，供研究人员和临床医生使用。

The research context:Nepal is classified as one of the lowest income countries on the Development Assistance Committee (DAC) list and the general health of the population is considered to be poor by most measures, even in comparison with the rest of Asia. Access to healthcare is severely restricted, particularly in rural regions, which is undoubtedly a limiting factor to progress, generally. We have identified a specific unmet clinical need within Nepal that is fully aligned with this call for proposals; aided as it could be by the provision of affordable, point-of-care imaging diagnostics. There is an unusually high prevalence (up to 43%) of the population in Nepal suffering from chronic obstructive pulmonary disease (COPD) and this has been the number one cause of death (>9%) there in recent years. This is thought to arise principally as a result of poor indoor air quality, with the condition being even more acute in difficult to reach, both geographically and economically, rural regions. It is particularly high amongst women, which may be largely attributable to the deeply embedded culture of indoor cooking and heating with biomass fuelsAims and objectives:Our aim is to develop a low cost miniaturized, integrated chip-based optical coherence tomography (OCT) based diagnostic tool which will provide a transformative change to the level of sophistication that access to such clinical imaging technology can bring to bear on COPD diagnosis and therapy. The key advance will stem from transitioning the fibre based interferometer at the heart of commercial OCT systems onto the silicon photonics chip, which will enable system complexity and cost reductions through manufacturing scalability. Silicon photonics is aptly suited to this because it is transparent at the target operating wavelength (1300nm) of most OCT systems and the required interferometer components have now all been demonstrated in isolation. Manufacturing of these sub-micron optical devices can be massively scaled at lower cost and to extremely high tolerances using the global passive fabrication infrastructure that has been built up around the telecommunications industry. In addition, many of these components have now also been realised in the silicon nitride (SiN) platform, extending capabilities down towards the visible range, which is particularly relevant to certain biomedical imaging regimes. We will develop SiN based interferometers in parallel with the silicon devices through wavelength scaled common optical circuit designs as proof of concept. Finally, we will take the ambitious step of developing a complete, fibre-less chip based solution by hybrid integration of miniature optical sources with the silicon/SiN based interferometers.Potential applications and benefits:The vision of a low complexity, low cost, miniature OCT system incorporated within existing bronchoscopy or catheter based medical devices that could be used along with commercially available data acquisition hardware and analytical software on a mobile platform is within reach. Such a system can provide the necessary access to a sophisticated imaging diagnostic tool that could displace basic spirometry and even fibre based bronchoscopy as the gold standard for early diagnosis of COPD. Its greatest benefit will be felt, initially, within remote regions of our partner LMIC country, Nepal where a high prevalence of the disease is exemplified and where access to such facilities is limited by both geography and economy. Improvements in resolution and speed for tissue imaging can also be expected to help improve our understanding of COPD progression in a fundamental way. For example the development and widespread adoption of the proposed OCT technology would generate population specific datasets of high quality for use by researchers and clinicians.