Development and Application of Fibre-Laser Based Excitation Sources for Biomedical Photoacoustic Imaging

生物医学光声成像光纤激光激励源的开发与应用

• 批准号: EP/J022144/1
• 负责人: Paul Beard
• 金额: $ 41.07万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ022144%2F1
• 关键词: Development; Application; Fibre; Laser; Based

The aim of this research is to develop a range of novel fibre based laser systems for use in a promising new medical and biological imaging technique. The technique, called photoacoustic imaging, works by forming an image from acoustic waves generated by the absorption of pulsed laser light in anatomical structures such as blood vessels. Its key advantage is that it overcomes the limited penetration depth/spatial resolution that purely optical imaging techniques suffer from due to the strong optical scattering exhibited by tissue. At the same time it retains their high contrast and spectral specificity enabling visualisation of anatomical features indistinguishable with other modalities such as ultrasound imaging. Potential clinical applications include imaging breast, oral and skin cancers, cardiovascular disease and skin abnormalities. It can also be used for imaging small animals such as mice which are used extensively in research to study a wide range of human diseases, especially cancer, and evaluate new drugs and other treatments.Laboratory based photoacoustic scanners have produced exquisite images of tissue structure and function and in doing so excited a great deal of interest in the biomedical imaging community. However, these studies have generally been proof-of-concept experiments aimed at showcasing feasibility rather than addressing a real clinical need or scientific question. The challenge that now lies ahead is to translate the technique to a practical imaging tool that can be used routinely for clinical applications or basic research in the life sciences. However, meeting this challenge is seriously compromised by the limitations of existing lasers used in photoacoustic imaging. These are typically too bulky, unreliable, often require specialist personnel for their operation and provide insufficient control over their temporal output. To overcome these shortcomings, a new generation of tunable excitation laser systems based on fibre laser and OPO technology will be developed and evaluated. This approach offers important advantages over existing photoacoustic excitation laser technology. These include compact size, high reliability and efficiency, high pulse repetition frequencies and the unique ability to arbitrarily modulate the laser output over a wide range of timescales (sub ns-ms). The latter offers the prospect of investigating a wide range of new time and frequency domain excitation methods which can be exploited to optimise SNR and spatial resolution and implement new methods for measuring blood flow. The project will entail developing a range of tunable laser systems based on novel high energy pulsed fibre lasers and custom designed OPOs. Two systems will be developed. One will be a high energy (mJ) fibre laser pumped OPO with an output in the 650-1050nm spectral range designed for full field photoacoustic tomography. The other will be a lower energy (uJ) system operating in the 450-750nm spectral range and designed to provide a diffraction limited beam for optical resolution photoacoustic microscopy. Both will be table-top, self-contained systems that are roughly the size of a desktop PC allowing them incorporated into a compact portable photoacoustic scanner for practical clinical or preclinical use. An integral part of the project will be the application of the technology. As well as in vivo imaging studies, this will involve developing novel signal processing techniques that exploit the unique diversity of temporal output that fibre lasers support in order to optimise imaging performance and functionality.By removing the principal technical translational bottleneck in photoacoustic imaging and thereby advancing it to practical application in the clinical and life sciences, this research is expected to have a transformative effect on this rapidly emerging field.

本研究的目的是开发一系列新型光纤激光系统，用于一种有前途的新型医学和生物成像技术。这项技术被称为光声成像，其工作原理是将血管等解剖结构吸收脉冲激光所产生的声波形成图像。它的主要优点是克服了纯光学成像技术由于组织表现出强烈的光学散射而受到的穿透深度/空间分辨率的限制。同时，它保留了其高对比度和光谱特异性，使解剖学特征的可视化与其他模式（如超声成像）难以区分。潜在的临床应用包括乳腺癌、口腔癌和皮肤癌、心血管疾病和皮肤异常的成像。它还可以用于小动物的成像，如老鼠，这些小动物被广泛用于研究各种人类疾病，特别是癌症，并评估新药和其他治疗方法。基于实验室的光声扫描仪已经产生了组织结构和功能的精美图像，并在这样做中引起了生物医学成像社区的极大兴趣。然而，这些研究通常是概念验证实验，旨在展示可行性，而不是解决真正的临床需求或科学问题。目前面临的挑战是将这项技术转化为一种实用的成像工具，可以常规用于临床应用或生命科学的基础研究。然而，由于光声成像中使用的现有激光器的局限性，解决这一挑战受到了严重的影响。这些设备通常体积太大，不可靠，往往需要专业人员操作，而且对其临时输出的控制不足。为了克服这些缺点，将开发和评估基于光纤激光器和OPO技术的新一代可调谐激励激光系统。与现有的光声激发激光技术相比，这种方法具有重要的优势。这些优点包括紧凑的尺寸，高可靠性和效率，高脉冲重复频率以及在宽时间尺度范围内（小于ns-ms）任意调制激光输出的独特能力。后者提供了研究广泛的新的时间和频域激励方法的前景，这些方法可以用来优化信噪比和空间分辨率，并实现测量血流的新方法。该项目将需要开发一系列基于新型高能脉冲光纤激光器和定制设计opo的可调谐激光系统。将发展两种制度。一种是高能（mJ）光纤激光泵浦OPO，其输出光谱范围为650-1050nm，设计用于全场光声层析成像。另一个将是一个低能量（uJ）系统，工作在450-750nm光谱范围内，旨在为光学分辨率光声显微镜提供衍射限制光束。这两种仪器都将是桌面式、独立的系统，大小与台式电脑大致相当，可以将它们集成到紧凑的便携式光声扫描仪中，用于实际临床或临床前使用。该项目的一个组成部分将是该技术的应用。以及体内成像研究，这将涉及开发新的信号处理技术，利用光纤激光器支持的独特的时间输出多样性，以优化成像性能和功能。通过消除光声成像的主要技术转化瓶颈，从而将其推进到临床和生命科学的实际应用中，这项研究有望对这一迅速崛起的领域产生变革性影响。

项目成果

High pulse energy fibre laser as an excitation source for photoacoustic tomography.

• DOI: 10.1364/oe.401708
• 发表时间: 2020-11
• 期刊: Optics express
• 影响因子: 3.8
• 作者: T. Allen;M. Berendt;D. Lin;S. Alam;N. Huynh;E. Zhang;D. Richardson;P. Beard

Ultrafast laser-scanning optical resolution photoacoustic microscopy at up to 2 million A-lines per second

• DOI: 10.1117/1.jbo.23.12.126502
• 发表时间: 2018-12-01
• 期刊: JOURNAL OF BIOMEDICAL OPTICS
• 影响因子: 3.5
• 作者: Allen, Thomas John;Spurrell, Josh;Beard, Paul C.
• 通讯作者: Beard, Paul C.