Name: pulsed laser diode-based desktop photoacoustic tomography for monitoring wash-in and wash-out of dye in rat cortical vasculature
Uploaded: 2019-05-30T15:00:00
Description: Watch this Scientific Journal Video about Pulsed Laser Diode-Based Desktop Photoacoustic Tomography for Monitoring Wash-In and Wash-Out of Dye in Rat Cortical Vasculature at JoVE.com

这项研究得到了新加坡卫生部国家医学研究委员会 (NMRC/OFIRGY000/2016:M4062012) 的支持。作者要感谢周伟宏博比先生对机器车间的支持。

所有动物实验都是根据新加坡南洋理工大学动物护理和使用机构委员会批准的指导方针和条例 (动物议定书编号 ARF-SBS/NIE-0331) 进行的。
1. 系统描述
<ol><li>将 PLD 激光安装到圆形扫描仪中, 并将光学扩散器 (OD) 安装在 PLD 出口窗口的前面, 以使输出光束均匀, 如图 1a 所示。将 PLD 连接到激光驱动器单元 (LDU)。 注: PLD 产生 ~ 816 nm 波长脉冲, 脉冲持续时间约 ...

<ol>
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U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+the+detection+of+intraplaque+hemorrhage+in+carotid+artery+lesions+using+photoacoustic+imaging.">Toward the detection of intraplaque hemorrhage in carotid artery lesions using photoacoustic imaging.</a> Journal of Biomedical Optics. 22 (4), (2016).</li><li>Daoudi, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Handheld+probe+integrating+laser+diode+and+ultrasound+transducer+array+for+ultrasound/photoacoustic+dual+modality+imaging.">Handheld probe integrating laser diode and ultrasound transducer array for ultrasound/photoacoustic dual modality imaging.</a> Optics Express. 22 (21), 26365-26374 (2014).</li><li>Allen, J. 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这项工作提出了一个协议, 使用桌面 PLD-PAT 系统进行实验小动物, 如老鼠体内大脑成像和动态快速吸收和清除过程的造影剂, 如 ICG。笨重、昂贵的 OPO-PAT 系统需要几分钟 (2-5) 才能获得体内单个横截面图像。紧凑、低成本、第一代便携式 PLD-PAT 系统可在5秒内提供单个体内横截面图像。相比之下, 高速、紧凑、低成本的台式机 PLD-PAT 系统仅在 0.5秒26中呈现高质量的2D 横截面体内图像?...

光声计算机断层扫描 (pactse-pat) 是一种很有前途的非侵入性生物医学成像方式, 它结合了丰富的光学对比度和高超声分辨率1,2,3, 4,5. 当纳秒脉冲激光将能量沉积到任何生物组织内的吸光色相中时, 局部温度升高, 导致组织的热弹性膨胀和收缩, 从而产生压力波。这些压力波被称为超声波或光声 (PA) 波, 可以通过样品周围的超声波传感器检测到。利用各种重建算法6、7、8、9对检测到的 pa 信号进行重构, 生成横截面 pa 图像。PA 成像提供结构和功能信息, 从宏观器官到微观细胞器, 由于存在于体内10的内源性色母象的波长依赖性。PAT 成像已成功地用于乳腺癌检测1, 前哨淋巴结成像11, 氧血红蛋白 (hbo2) 的映射, 脱氧血红蛋白 (HbO), 总血红蛋白浓度 (HbO), 氧饱和度 (so2)12,13、肿瘤血管生成14例, 小动物全身成像15例, 等应用。
Nd:yag/opo 激光器是第一代 PAT 系统的常规激发源, 广泛应用于光声界的小动物成像和深层组织成像16。这些激光器在 ~ 10-100 Hz 的低重复率下提供 ~ 100 mJ 能量脉冲。由于脉冲重复率有限, 使用这些昂贵且笨重的激光的 PAT 成像系统不适合使用单元素超声传感器 (Sut) 进行高速成像。这就抑制了对动物体内高速发生的生理变化的实时监测。使用基于阵列的传感器, 如带有 nd:yag 激光激发的线性、半圆、圆形和体积阵列, 可以进行高速成像。然而, 这些阵列传感器价格昂贵, 与 Sut 相比, 它们的灵敏度较低;然而, 成像速度受到激光低重复率的限制。最先进的单脉冲 PACT 系统与定制的全环阵列传感器获得 PA 数据在 50 Hz 帧速率17.这些阵列传感器需要复杂的后端接收电子和信号放大器, 使整个系统更加昂贵, 临床使用更加困难。
其紧凑的尺寸、较低的成本要求和较高的脉冲重复率 (KHz 顺序) 使脉冲激光二极管 (Pld) 更有前途, 适用于实时成像。由于这些优点, 在第二代 PAT 系统中, Pld 被积极用作备用励磁源。基于pld 的 pat 系统已成功地证明, 高帧率成像使用阵列传感器 18, 深组织和大脑成像19,20,21, 心血管疾病诊断22和风湿病诊断23。由于与阵列传感器相比, Sut 具有高度敏感和更低的成本, 因此它们仍被广泛用于 PAT 成像。基于光纤的 PLD 系统已被证明用于幻象成像 24。以前通过将 PLD 安装在 PAT 扫描仪25内, 已经演示了便携式 pld-pat 系统。使用一个 SUT 圆形扫描仪, 在3次扫描时间内进行幻影成像, 并在5维使用 PLD-PAT 系统19在5个时间内进行大鼠脑成像。
此外, 还对该 pld-pat 系统进行了改进, 使其更加紧凑, 并使用8个基于声学反射的单元素超声波传感器 (subr)26、27创建桌面模型。在这里, Sut 被放置在一个垂直的, 而不是水平的方向, 在90°声学反射器28的帮助下。该系统可用于组织成像和体内小动物大脑成像中的扫描时间高达 0.5 s 和约3厘米深。在这项工作中, 这个桌面 PLD-PAT 系统用于提供实验的视觉演示, 用于在小动物的体内大脑成像和动态可视化的吸收和清除过程的食品和药物管理局 (FDA) 批准的碘苯胺大鼠大脑中的绿色染料 (ICG)。

<table>
	<tbody>
		<tr>
			<td>12 V power supply</td>
			<td>Voltcraft</td>
			<td>PPS-11810</td>
			<td>To supply operating voltage for PLD</td>
		</tr>
		<tr>
			<td>Acoustic reflector</td>
			<td>Olympus</td>
			<td>F102</td>
			<td>45 degree reflector augmented to the ultrasound transducer</td>
		</tr>
		<tr>
			<td>Acrylic water tank</td>
			<td>NTU workshop</td>
			<td>Custom-made</td>
			<td>It is used to hold water that acts as an acoustic coupling medium between animal brain and detector</td>
		</tr>
		<tr>
			<td>Anesthetic Machine</td>
			<td>Medical plus pte ltd</td>
			<td>Non-Rebreathing Anaesthesia machine with oxygen concentrator.</td>
			<td>Supplies oxygen and isoflurane to animal</td>
		</tr>
		<tr>
			<td>Animal distributor</td>
			<td>In Vivos Pte Ltd, Singapore</td>
			<td></td>
			<td>Animal distributor that supplies small animals for research purpose</td>
		</tr>
		<tr>
			<td>Animal holder</td>
			<td>NTU workshop</td>
			<td>Custom-made</td>
			<td>Used for holding animal on its abdomen</td>
		</tr>
		<tr>
			<td>Breathing mask</td>
			<td>NTU workshop</td>
			<td>Custom-made</td>
			<td>Used along with animal holder to supply anesthesia mixture to the animal</td>
		</tr>
		<tr>
			<td>Circular Scanner</td>
			<td>NTU workshop</td>
			<td>Custom-made</td>
			<td>Scanner is made out of aluminum</td>
		</tr>
		<tr>
			<td>DAQ (Data acquisition) Card</td>
			<td>Spectrum</td>
			<td>M2i.4932-exp</td>
			<td>16 bit, 30 Ms/s, 8 channels, 1 Gs, PCIe</td>
		</tr>
		<tr>
			<td>Data acqusition software</td>
			<td>National Instruments Corporation,Austin,TX,USA)</td>
			<td>NI LabVIEW 2015 SP1 (32 bit)</td>
			<td>LabVIEW based program developed in our laboratory for controlling the stepper motor and acquring the PA singnals from the detector</td>
		</tr>
		<tr>
			<td>Data processing software</td>
			<td>Matlab (Mathworks, Natick, MA, USA)</td>
			<td>Matlab R2015b</td>
			<td>Matlab code developed in our laboratory for reconstructing cross-sectional PA images</td>
		</tr>
		<tr>
			<td>Function generator</td>
			<td>RIGOL</td>
			<td>DG1022</td>
			<td>To change the repetition rate of the PLD. It will provide TTL signal to synchronize the DAQ with the laser excitation.</td>
		</tr>
		<tr>
			<td>Low noise signal amplifier</td>
			<td>Genetron</td>
			<td>Custom-made using Mini-circuits, ZFL-500LN-BNC</td>
			<td>To receive, and amplify the PA signal from SUTR. Its gain is 24 dB.</td>
		</tr>
		<tr>
			<td>Optical diffuser</td>
			<td>Thorlabs</td>
			<td>DG-120</td>
			<td>Used to to make the laser beam homogeneous</td>
		</tr>
		<tr>
			<td>Pulsed laser diode</td>
			<td>Quantel, France</td>
			<td>QD-Q1924-ILO-WATER</td>
			<td>It is the excitation laser source with specifications of 816 nm wavelength, 3.4 mJ per pulse energy, 107 ns pulse width, 2 KHz maximum pulse repitition rate, dimensions : 13.0 x 7.6 x 5.0 cm</td>
		</tr>
		<tr>
			<td>Rats</td>
			<td>In Vivos Pte Ltd, Singapore</td>
			<td>NTac:SD, Sprague Dawley / SD</td>
			<td>Female, weight 100&#177;10g, strain of rats: Sprague Dawley, age: 4-5 weeks</td>
		</tr>
		<tr>
			<td>Stepper motor with gearbox</td>
			<td>LIN Engineering (Servo Dynamics)</td>
			<td>Motor: CO-5718L-01P-RO, Gearbox: DPL64/1; Power supply PW-100-24</td>
			<td>To move the detector holder in a circular geometry. Torque: 2.08 N-m, Rotor inertia: 2.6 kg-cm2</td>
		</tr>
		<tr>
			<td>Ultrasound gel</td>
			<td>Progress/parker acquasonic gel</td>
			<td>PA-GEL-CLEA-5000</td>
			<td>Clear ultrasound gel</td>
		</tr>
		<tr>
			<td>Ultrasound Transducer</td>
			<td>Olympus</td>
			<td>V309-SU/ U8423013</td>
			<td>Ultrasonic sensors used for photoacoustic detection. Central freqency 5 MHz, 0.5 in</td>
		</tr>
		<tr>
			<td>Variable high voltage power supply</td>
			<td>Elektro-Automatik</td>
			<td>EA-PS 8160-04 T</td>
			<td>To change the laser output power</td>
		</tr>
	</tbody>
</table>

pulsed laser diode-based desktop photoacoustic tomography for monitoring wash-in and wash-out of dye in rat cortical vasculature

光声 (PA) 断层扫描 (pat) 成像是一种新兴的生物医学成像模式, 适用于各种临床前和临床应用。定制的基于圆形环阵列的传感器和传统的笨重 Nd: YAG/OPO 激光器抑制了 PAT 系统的转换到诊所。超紧凑型脉冲激光二极管 (Pld) 目前正被用作 PA 成像的近红外激发的替代来源。高速动态体内成像已被证明使用了紧凑型基于 pld 的桌面 PAT 系统 (PLD-PAT)。本文提出了一种利用桌面 PLD-PAT 系统进行动态脑成像的可视化实验方案。该协议描述了桌面 PLD-PAT 系统配置、脑血管成像动物的制备以及大鼠皮质血管中肌内腺绿色 (ICG) 染料吸收和清除过程的动态成像过程。

该协议展示了所描述的桌面 PLD-PAT 系统在体内动态脑成像中的潜力, 并给出了相应的结果。通过对健康雌性大鼠进行体内脑成像, 证明了桌面 PLD-PAT 系统的高速成像能力。PA 信号是使用 8个 SUTRs 在360°和45°周围的大鼠大脑中旋转收集的, 扫描速度分别为4秒和0.5秒。图 2A. b 显示了一只雌性大鼠 (98 克) 的大脑图像, 扫描速度分别为4秒和0.5秒。在这两个图像中都可?...

Watch this Scientific Journal Video about Pulsed Laser Diode-Based Desktop Photoacoustic Tomography for Monitoring Wash-In and Wash-Out of Dye in Rat Cortical Vasculature at JoVE.com

Pulsed Laser Diode-Based Desktop Photoacoustic Tomography for Monitoring Wash-In and Wash-Out of Dye in Rat Cortical Vasculature

基于脉冲激光二极管的桌面光声层析成像在大鼠皮质血管内监测染料的洗入和洗脱

基于平板脉冲激光二极管的桌面光声层析成像 (LDD-PAT) 系统被证明用于小动物皮质血管的高速动态体内成像。

Photoacoustic (PA) tomography (PAT) imaging is an emerging biomedical imaging modality useful in various preclinical and clinical applications. ...

光声断层扫描学（PAT）是一种成像混合生物医学成像模式，结合了光学和超声波成像，用于监测小动物大脑的动态变化。这是一个经济高效的便携式高速成像系统，使用成像速度短到半秒。与桑迪普一起演示这个程序的将是博士生普拉文、研究员保罗博士和研究助理罗尼。首先将所有单元件超声波传感器安装到每个传感器支架上，使每个声学反射器的表面朝向扫描区域的中心。使用连接电缆将每根传感器电缆连接到低噪声信号放大器。打开冷水机组的电源并打开冷水机组开关，将温度设置为 20 至 25 摄氏度。打开低压电源，然后缓慢地将电流控制转动到 0.3 安培。将电压设置为 12 伏，并验证电流不超过 0.1 安培。打开高压电源，按预设按钮将电流设置为一安培，将电压设置为零伏特。启用输出按钮并打开功能发生器的电源。按下召回按钮并选择两千赫的配置，以此重复速率生成激光脉冲。将丙烯酸罐放在扫描仪内，向水箱加注水，直到传感器的检测表面完全浸入。然后打开低噪声信号放大器的电源。将麻醉大鼠放在工作台上的易发位置。在确认对手趾捏没有反应后，使用头发修剪器去除头皮上的毛皮。轻轻涂抹脱毛霜，使用棉签将毛皮完全从裸露的皮肤中去除，在四到五分钟后取出霜。将软膏涂抹在动物的眼睛上，并在实验室插孔上安装装有呼吸面罩的定制动物支架。将大鼠放在支架上的易发位置，头部放在支架的水平平台上。使用手术胶带将动物固定到支架上。将脉搏血小计夹住一个后肢，以监测其生理状况。使用棉尖施用器将一层无色超声波凝胶涂在头皮上。然后将实验室插孔位置调整到扫描仪的中心。手动调整插孔的高度，使成像平面位于声学反射器的中心。在数据采集软件中为 360 度采集扫描设置参数后，使功能发生器的输出能够打开脉冲激光二极管激光发射。缓慢地将可变高压电源的电压提高至 120 伏，实现每个脉冲能量的最大功率。运行数据采集软件程序，在四秒扫描时间中旋转所有八个传感器 360 度。禁用功能发生器的输出以关闭激光发射。利用数据处理软件中的重建算法，利用背投影算法，通过试验和误差确定所有8个传感器的扫描半径。在 0.5 秒扫描时间上为 45 度采集设置数据采集软件中的参数。使功能发生器的输出打开激光发射。运行数据采集软件程序，将所有八个传感器旋转 45 度以获取初始控制数据。禁用功能发生器的输出以关闭激光发射。接下来，在大鼠的尾静脉中注射0.3毫升的丁二氨酸绿色。使功能发生器的输出打开激光发射。然后运行数据采集软件，在 45 度旋转的 0.5 秒扫描时间中获取 A 线。在采集结束时，使用背投影算法从保存的 A 线重建横截面脑图像。在这里，从98克雌性大鼠的大脑图像，收集在4和0.5秒扫描速度显示。下垂鼻窦和转移鼻窦在这两个图像中清晰可见。照片显示了取出头皮之前和之后大鼠大脑的相同区域。光声断层成像可以实现相同的可视化无创与皮肤和头骨完好无损。在此图中，可以观察到，由于一段时间内860纳米波长的影绿增加和随后减少的光听光信号，射手鼻窦中的平均光声信号增加。将 ICG 染料注射到动物的尾静脉中时，请格外小心。这种低成本的桌面光声断层扫描系统可用于以0.5秒扫描速度进行高特殊分辨率的小型动物脑血管的动态成像。此成像系统的其他应用包括脑肿瘤成像、小动物不同器官的成像和其他治疗应用。

Research

JoVE Journal

Bioengineering

Three-dimensional Optical-resolution Photoacoustic Microscopy

三维光学分辨率的光声显微镜

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As ...

科研

生物工程

Detection and Isolation of Circulating Melanoma Cells using Photoacoustic Flowmetry

使用光声血流循环黑色素瘤细胞的检测和隔离

Circulating tumor cells (CTCs) are those cells that have separated from a macroscopic tumor and spread through the blood and lymph systems to seed ...

Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography

集成光声眼底镜检查和谱域光学相干断层扫描

Both the clinical diagnosis and fundamental investigation of major ocular diseases greatly benefit from various non-invasive ophthalmic imaging ...

Mass Cytometry: Protocol for Daily Tuning and Running Cell Samples on a CyTOF Mass Cytometer

质量流式细胞术：协议，每日调整和执行细胞的样品上一个CyTOF的质量流式细胞仪

In recent years, the rapid analysis of single cells has commonly been performed using flow cytometry and fluorescently-labeled antibodies. However, the ...

Anatomical Reconstructions of the Human Cardiac Venous System using Contrast-computed Tomography of Perfusion-fixed Specimens

人类心脏静脉系统使用对比计算机断层扫描灌注固定的标本解剖重建

A detailed  understanding of the complexity and relative variability within the human  cardiac venous system is crucial for the development of cardiac ...

Photoacoustic Cystography

光声膀胱造影

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The ...

Production of Metal Nanoparticles by Pulsed Laser-ablation in Liquids: A Tool for Studying the Antibacterial Properties of Nanoparticles

液体中脉冲激光烧蚀制备金属纳米粒子：研究纳米粒子抗菌性能的工具

The emergence of multidrug-resistant bacteria is a global clinical concern leading some to speculate about our return to a "pre-antibiotics" era of ...

Switchable Acoustic and Optical Resolution Photoacoustic Microscopy for In Vivo Small-animal Blood Vasculature Imaging

Switchable Acoustic and Optical Resolution Photoacoustic Microscopy for In Vivo Small-animal Blood Vasculature Imaging

可切换声光学分辨率光声显微镜<em&gt;体内</em&gt;小动物血液血管成像

Photoacoustic microscopy (PAM) is a fast-growing invivo imaging modality that combines both optics and ultrasound, providing penetration beyond the ...

A High-performance Compact Photoacoustic Tomography System for In Vivo Small-animal Brain Imaging

A High-performance Compact Photoacoustic Tomography System for In Vivo Small-animal Brain Imaging

高性能紧凑型光声层析成像系统<em&gt;体内</em&gt;小动物脑成像

In vivo small-animal imaging has an important role to play in preclinical studies. Photoacoustic tomography (PAT) is an emerging hybrid imaging modality ...

Proper Positioning and Restraint of a Rat Hind Limb for Focused High Resolution Imaging of Bone Micro-architecture Using In Vivo Micro-computed Tomography

Proper Positioning and Restraint of a Rat Hind Limb for Focused High Resolution Imaging of Bone Micro-architecture Using In Vivo Micro-computed Tomography

应用活体显微计算机断层成像技术对骨微结构高分辨成像大鼠后肢的定位与抑制

The use of in vivo micro-computed tomography (&#181;CT) is a powerful tool which involves the non-destructive imaging of internal structures at high ...