Measuring blood oxygenation in vivo by photoacoustic imaging

血液氧合是生理功能的关键量度。然而，很少有技术能够可靠地非侵入性地测量氧合。在这个跨学科的研究中，学生将进行实验成像研究和计算建模，以开发一种方法来测量氧合使用一种新的技术称为光声断层扫描。该技术将在幻影和肾脏中进行测试，肾脏具有与其生物功能相关的不同区域的氧合区域，并在化学损伤诱导的缺氧模型中进行测试。如果成功，这项技术将彻底改变临床前成像技术，并可应用于多种生理过程和病理条件。博士项目：目的和描述（限300字）血氧是组织功能和病理学的重要生理指标，与病理生理学过程的研究有关，如肿瘤中的血管生成、组织炎症和愈合反应。多波长光声断层扫描（PAT）有可能提供比目前可能的分辨率更高的高分辨率氧合3D图像。这将改变临床前成像，但仍然存在一个障碍。有一个不平凡的光谱步骤，虽然已经开发出有前途的数学解决方案，将这些转化为临床前应用的强大程序是具有挑战性的。为了成功，这个项目将需要实验和算法方面的问题一起考虑。最初，最佳波长选择技术将在phanomedium的数值和实验探索，以确定其实际适用性估计氧合。为了更准确（但更慢）的估计，将考虑采用蒙特卡罗光学模型和k空间超声模型的非线性优化。现有的原型算法将开发和使用的实验数据。BC将与实验人员（由PB领导）合作监督这方面的工作。在体模实验（参见旋转项目）之后，设想了一系列体内临床前实验。首先，将对小鼠侧腹中的血管进行成像，并将氧合估计值与一氧化碳血氧计值进行比较。在此验证之后，将获得正常小鼠肾脏的图像，以检查该技术的生理相关性。这些方面将由DL指导。肾脏在髓质中含有促进重吸收过程的缺氧区域，因此为PAT成像提供了理想的测试平台。然后将在小鼠中使用氯化钴等化学损伤来诱导缺氧（在多种病理条件下发生），以检查PAT是否可以检测病理情况下的氧变化。将PAT估计值与当前用于检测氧水平的方法（如hypoxyprobe给药）进行比较。

Blood oxygenation is a critical measure of physiological function. However, there are very few techniques to reliably measure oxygenation non-invasively. In this interdisciplinary studentship, the student will undertake experimental imaging studies and computational modelling to develop a method to measure oxygenation using a novel technique called photoacoustic tomography. The technique will be tested in phantoms and the kidney, which has different regional areas of oxygenation related to its biological function and in models of hypoxia induced by chemical insults. If successful, this technique would revolutionise preclinical imaging techniques and could be applied to multiple physiological processes and pathological conditions. PhD project: aims and description (limit 300 words)Blood oxygenation is an important physiological indicator of tissue function and pathology, relevant to the study of pathophysiological processes such as angiogenesis in tumours, tissue inflammation and healing responses. Multiwavelength photoacoustic tomography (PAT) has the potential to provide high resolution 3D images of oxygenation at higher resolution than is currently possible. This would transform preclinical imaging, but one hurdle remains. There is a non-trivial spectroscopic step, and while promising mathematical solutions have been developed, translating these into robust procedures for preclinical application is challenging. To succeed, this project will require both the experimental and algorithmic aspects of the problem to be considered together.Initially, optimal wavelength selection techniques will be explored numerically and experimentally in phantoms to determine their practical applicability to estimating oxygenation. For more accurate (but slower) estimation, nonlinear optimisations employing Monte Carlo optical models and k-space ultrasound models will be considered. Existing prototype algorithms will be developed and used with experimental data. BC will supervise this aspect in collaboration with experimentalists (led by PB). After phantom experiments (see Rotation project), a series of in vivo preclinical experiments are envisaged. First, vessels in the mouse flank will be imaged, and oxygenation estimates compared with co-oximeter values. Following this validation, images of the normal mouse kidney will be obtained to examine the technique's physiological relevance. These aspects will be guided by DL. The kidney contains areas of hypoxia in the medulla which facilitate the reabsorption processes, therefore providing an ideal test-bed for PAT imaging. Chemical insults such as cobalt chloride will then be used in mice to induce hypoxia (which occurs in multiple pathological conditions) to examine whether PAT can detect oxygen changes in a pathological situation. The PAT estimates will be compared with current methods used to detect oxygen levels such as hypoxyprobe administration.