Development and application of a non-contact, depth-resolved optical skin oximeter

非接触式深度分辨光学皮肤血氧仪的研制与应用

基本信息

批准号：
EP/C520815/2
负责人：
Stephen Matcher
金额：
--
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FC520815%2F2
关键词：
Development application non contact depth

项目摘要

Oxygen is vital for life. Every cell in the body requires a continuous supply of oxygen or it will die. The delivery of oxygen from the lungs to cells is the most important function of the microcirculation. The skin represents the largest organ' of the body and plays a vital role in protecting the body from the outside environment. Its health is thus of critical importance to our general well-being. The skin is comprised of distinct layers. the uppermost layer is the stratum corneum and consists of dead cells. Below this lies the epidermis, about 0.1mm thick and below this is the dermis. 1-2 mm thick. The epidermis is unique in that it contains living cells but no blood vessels: to remain alive it relies totally on the passive diffusion of oxygen from elsewhere. If the supply of oxygen to the epidermis is interrupted for any reason then a serious medical condition is likely to result. Painful skin conditions such as venous ulcers. pressure ulcers (e.g. 'bed sores') or diabetic ulcers (i.e. the condition known as 'diabetic foot ) are potentially caused by disturbed oxygen transport to the epidermis. There is thus a need to measure oxygen delivery to the skin via the microcirculation.Over 50 years ago an approach was suggested that has remained of value today. The American scientist Millikan demonstrated that optical spectroscopy can measure the amount of oxygen bound to haemoglobin in blood via changes in the colour of haemoglobin. Oxygenated haemoglobin. which predominates in arterial blood, appears bright crimson whereas deoxygenated haemoglobin. more prevalent in venous blood. appears reddish-brown. Millikan used this effect to allow American bomber pilots to check that they were breathing in sufficient oxygen whilst flying at altitudes of 5-6 miles. All current instruments are of the same basic conceptual design as Millikan's instrument. Consequently they have limitations that become very restrictive when studying the skin. The microcirculation of the skin is highly structured on a depth-scale of 1 mm. but current instruments provide no direct information about the distribution of oxygenated haemoglobin with depth. The devices make physical contact with the skin. which can easily produce mechanical pressures sufficient to close off the smallest blood vessels and thus distort the measurements. Our project proposal is to use modern technology. developed over the last few years. to address these shortcomings and build a better optical skin oximeter.Our approach will apply an optical analogue of ultrasound imaging called optical coherence tomography (OCT), which has emerged over the last 12 years as the most promising new optical technique for skin imaging. Spectroscopic OCT can yield depth-resoived information about the distribution of absorbing compounds by performing OCT at a number of different wavelengths. To date, this technique has mainly been used to measure the water content of tissues, as water shows a strong absorption band between 1.3 pm and 1.55 pm. OCT light sources are commonly available at these wavelengths because they are also the wavelengths used for optical fibre communications. Spectroscopic OCT has not been attempted over the wavelength range 450 to 600 nmi ideal for measuring haemoglobin oxygenation, due to the unavailability of suitable light sources. Spectroscopic OCT at these wavelengths can form the basis of the next generation of skin oximeters, effectively overcoming all the limitations of current devices. Recently the chief technical obstacle, the lack of blue-green OCT sources, has started to be overcome via the invention of supercontinuum' light sources.Our project will explore the potential that blue-green spectrosopic OCT. using this new type of light source, has for improving the diagnosis and management of skin conditions that involve disturbed oxygen delivery by the microcirculation.

氧气对生命至关重要。体内的每个细胞都需要持续供应氧气，否则就会死亡。将氧气从肺部输送到细胞是微循环最重要的功能。皮肤是身体最大的器官，在保护身体免受外界环境影响方面发挥着至关重要的作用。因此，它的健康对我们的整体福祉至关重要。皮肤由不同的层组成。最上层是角质层，由死细胞组成。下面是表皮，厚约0.1毫米，下面是真皮。 1-2毫米厚。表皮的独特之处在于它含有活细胞但没有血管：为了保持活力，它完全依赖于来自其他地方的氧气的被动扩散。如果表皮的氧气供应因任何原因中断，则可能会导致严重的健康状况。皮肤疼痛，例如静脉溃疡。压疮（例如“褥疮”）或糖尿病性溃疡（即“糖尿病足”）可能是由于表皮的氧气输送受到干扰而引起的。因此，需要测量通过微循环输送到皮肤的氧气量。50 多年前就提出了一种方法，至今仍然具有价值。美国科学家密立根证明，光谱法可以通过血红蛋白颜色的变化来测量血液中与血红蛋白结合的氧气量。含氧血红蛋白。它在动脉血中占主导地位，呈明亮的深红色，而脱氧血红蛋白则呈鲜红色。多见于静脉血。呈现红棕色。密立根利用这种效应让美国轰炸机飞行员能够检查他们在 5-6 英里高度飞行时是否吸入了足够的氧气。目前所有的仪器都与密立根的仪器具有相同的基本概念设计。因此，它们的局限性在研究皮肤时变得非常严格。皮肤的微循环在 1 毫米的深度范围内高度结构化。但目前的仪器无法提供有关含氧血红蛋白随深度分布的直接信息。这些设备与皮肤进行物理接触。它很容易产生足以封闭最小血管的机械压力，从而扭曲测量结果。我们的项目建议是使用现代技术。近几年发展起来的。为了解决这些缺点并构建更好的光学皮肤血氧计。我们的方法将应用一种称为光学相干断层扫描 (OCT) 的超声成像光学模拟，该技术在过去 12 年中已成为最有前途的皮肤成像新型光学技术。光谱 OCT 通过在多个不同波长下执行 OCT 可以产生有关吸收化合物分布的深度分辨信息。迄今为止，该技术主要用于测量组织的含水量，因为水在下午 1.3 点至下午 1.55 点之间显示出强吸收带。 OCT 光源通常可用于这些波长，因为它们也是用于光纤通信的波长。由于缺乏合适的光源，尚未尝试在 450 至 600 nmi 的波长范围内进行光谱 OCT，该范围非常适合测量血红蛋白氧合。这些波长的光谱 OCT 可以构成下一代皮肤血氧计的基础，有效克服当前设备的所有局限性。最近，通过超连续谱光源的发明，已经开始克服蓝绿OCT光源缺乏的主要技术障碍。我们的项目将探索蓝绿光谱OCT的潜力。使用这种新型光源，可以改善涉及微循环氧气输送紊乱的皮肤状况的诊断和管理。