Optical Confirmation of Nasogastric Tube Placement with Early Photon Imaging

放置肠内喂食管（鼻胃管/NGTs）是一项标准的医疗程序，但放置不当是一个严重的问题（例如，食物进入肺部，导致肺部并发症导致死亡和残疾）。鉴于需要保护工作人员以及等待x射线设备可用或运送到x射线设备，目前的做法严重依赖电离x射线辐射在程序期间定位医疗设备，这会造成严重干扰。因此，有重要的临床驱动因素来开发替代的安置确认方法。我们已经开发了一种光学技术（无x射线），通过紧凑的床边系统来增强和引导NGT的放置。我们已经展示了一种突破性的方法来跟踪和显示正确的NGT胃放置（或错误放置在肺）使用单光子成像。我们的方法利用了这样一个事实：如果在身体内部放置一个点光源，那么一小部分光将有效地以一条直线从身体中射出。至关重要的是，这些视线内的光子（光粒子）保存着关于组织内点源空间位置的精确信息。我们可以利用这些信息，因为视距光子离开身体的速度比沿着更长的路径散射的更漫射的光子更快——我们能够使用一种称为时间相关单光子计数（TCSPC）的技术来检测和专门观察和使用快速光子。与不记录光子到达时间的“普通”相机不同，基于tcspc的成像依赖于使用在精确已知时间产生短脉冲的光源，以及记录到达时间的单光子敏感探测器。因此，TCSPC成像使我们能够设计一种成像系统，可以在漫射散射光子开始出现之前选择性地检测和成像视距光子的位置，从而使我们能够精确定位光源。虽然我们已经初步展示了这项技术在定位ngt方面的潜力，但我们正在提高检测速度，使用最新的探测器提供实时跟踪——类似于开发用于自动驾驶汽车的探测器。我们还将我们的技术与放置在NGT中的新型光纤光学相结合，这些光纤光学具有沿其长度间隔的光源，可以在放置或重新确认期间观察完整的NGT路径。我们现在打算完成临床原型设备并完成临床前验证，包括确定诊断准确性。然后，我们将评估设备引导患者植入NGT的可行性和安全性。我们的目标是减少与NGT放置（和再次确认）相关的重大不良事件，使放置更快，增强临床工作流程（不需要x光），通过更早地开始喂养/用药来改善患者的预后，并降低总体成本。

Placement of enteral feeding tubes (nasogastric tubes/NGTs) is a standard medical procedure, yet misplacement is a serious issue (e.g. food entering the lungs with consequent death and disability from pulmonary complications). Current practice relies heavily on ionising X-ray radiation to localise medical devices during procedures causing significant disruption given the need to protect staff as well as waiting for the availability of, or transport to, X-ray equipment. There are therefore significant clinical drivers to develop alternative placement confirmation methods. We have developed an optical technology (no X-rays) to augment and guide NGT placement using a compact bed-side system.We have demonstrated a ground-breaking approach to track and show correct NGT stomach placement (or misplacement in the lung) using single photon imaging. Our approach exploits the fact that if a point source of light is placed inside the body, a tiny fraction of the light will emerge from the body effectively in a straight line. Crucially, these line-of-sight photons (particles of light) hold precise information about the spatial location of the point source inside the tissue. We can utilise this information as the line-of-sight photons exit the body faster than the more diffuse photons that have been scattered along a longer path to exit the body - we are able to use a technique known as time-correlated single-photon counting (TCSPC) to detect and specifically observe and use the fast photons. In contrast to "normal" cameras, which do not record the arrival time of the photons, TCSPC-based imaging relies on using a light source that produces short pulses at precisely known times, together with a single-photon sensitive detector that records arrival times. Therefore, TCSPC imaging allows us to design an imaging system that can selectively detect and image the location of the line-of-sight photons before the diffuse scattered photons start to emerge, allowing us to precisely locate the source.Although we have initially demonstrated the potential of this technique to locate NGTs, we are increasing the detection speed to provide real time tracking using the newest detectors - similar to those in development for self-driving cars. We have also combined our technique with new optical fibres optics placed in the NGTs, which have light sources spaced along their length allowing observation of the full NGT path during placement or reconfirmation.We now intend to finalise the clinical prototype device and complete preclinical validation, including determining diagnostic accuracy. We will then move to evaluating feasibility and safety of the devices' ability to guide NGT placement in patients.Our goal is to reduce significant adverse events associated with NGT placement (and reconfirmation), make placement faster, enhance clinical workflows (removing need for x-rays), improve patient outcomes through initiating feeding/medication earlier and reduce overall costs.