作者感谢中国国家自然科学基金（61822505;11774101;61627827:81630046）、中国广东省科技规划项目（2015B020233016）和广州科技计划（201902001）的资助。

所有动物实验均按照中国广州华南师范大学动物护理与使用委员会提供的指南进行。
1. 系统设置
<ol><li>光学路径 （图 1）<ol>
<li>使用 532 nm 脉冲激光作为系统激光源。将激光的重复速率设置为 10 kHz，输出能量设置为 100%，使用用户定义的程序将触发器设置为外部触发器。</li>
		<li>通过光纤耦合器 （FC1） 将激光束耦合到单模光纤 （SMF）。在二维机动阶段（电机，最大速度:20 mm/s）上使用光纤校准器 （FC2） 对激光束进行协调。</li>
		<li>使用双轴气压计扫描仪（Galva）偏转激光束。使用可移动镜（M1）反射光束。通过 4×目标透镜聚焦光束（OL，数光圈:0.1）。</li>
		<li>使用XY翻译器安装（TM）修复自制的中空超声波传感器（UT，中央频率:25 MHz:带宽:90%以上:中心孔:3毫米）在OL12的底部。将聚焦光束穿过超声波传感器的中心孔。</li>
	</ol>
</li>
	<li>扫描路径<ol>
<li>在 WIM 期间使用现场可编程门阵列 （FPGA 2） 锁定 Galva。通过用户定义的程序设置适当的扫描范围和扫描速度。</li>
		<li>在 RIM 期间，使用现场可编程门阵列 （FPGA 1） 锁定电机。使用 FPGA 2 设置扫描频率和扫描点数。使用用户定义的程序来控制开始并停止扫描。</li>
	</ol>
</li>
	<li>数据采集<ol>
<li>使用 50 dB 放大器 （AMP） 放大 PA 信号。通过数据采集卡 （DAQ） 对信号进行数字化。通过 FPGA 1 或 FPGA 2 获取触发信号。</li>
		<li>使用图形处理单元 （GPU） 处理数据并行显示图像13。</li>
	</ol>
</li>
	<li>CCD 成像系统<ol>
<li>使用环形白色 LED（颜色温度:6500 K;光亮度: 40000 勒克斯:直径:7.5厘米）作为照明源。取出 M1，使用固定镜面 （M2） 反射光线。</li>
		<li>使用 PA 成像系统上的 CCD 摄像机（630 万像素）记录图像。用显示软件显示图像。</li>
	</ol>
</li>
</ol>2. 系统对齐
<ol><li>选择一个水箱（10厘米×10厘米×4.4厘米;下窗:3厘米×3厘米）。使用聚乙烯膜覆盖整个水箱（膜厚:10μm）。加入足够的超纯水。</li>
	<li>将水箱放在工作台上。</li>
	<li>打开激光开关。选择激光控制程序。预热5分钟。按泵开关上的"打开"按钮。将激光参数设置为每个步骤 1.1.1。打开激光的挡板。</li>
	<li>选择 A 线收集程序。按"开始"按钮捕获单点信号，并显示当前 A 线信号的振幅和频谱。</li>
	<li>将刀片放在水箱底部。将UT的底部浸入水箱中进行声学耦合。避免在UT的底部出现气泡。</li>
	<li>调整 Galva 的位置，在 UT 和 OL 之间调整 XY 翻译器以避免振荡信号，并确保这是共处的。</li>
	<li>调整工作阶段的高度，最大化信号的振幅，确定对焦位置。</li>
</ol>3. 动物实验
<ol><li>使用体重为 20+u201230 g 的 5+u20126 周大 BALB/c 鼠标。</li>
	<li>在实验前用注射的尿素（1克/千克）麻醉动物。</li>
	<li>在 WIM 和 RIM 之间进行过渡。<ol>
<li>使用平面超声波传感器。使用修剪器和脱毛霜剃掉鼠标背面的毛皮。将鼠标放在支架上（8 厘米× 2.8 厘米× 2 厘米）处于易发位置。</li>
		<li>使用超声波凝胶使成像区域与聚乙烯膜接触。避免接触部分出现气泡。</li>
		<li>将支架放在工作台上进行声学耦合。按照步骤 2.3\u20122.4 启动激光并收集 A 线信号。按照步骤 2.6\u20122.7 对齐。按"停止"以在对齐后结束集合。</li>
		<li>选择 WIM 程序。命名新创建的文件夹。将扫描参数设置为 20 mm/s 在"扫描速度"选项卡中，"扫描区域"选项卡中的"20 mm*20 mm"，以及"步骤"选项卡中的"20"。单击 "收集 "按钮开始扫描。</li>
		<li>单击 "停止" 按钮以在获取后结束扫描。单击 返回为零 ，将电机恢复为零。关闭激光挡板。将触发器设置设置为内部触发器。按下抽水开关的 关闭 按钮。</li>
		<li>将 WIM 扳机替换为 RIM 触发器，并将其连接到外部激光扳机。按下用于泵送开关的 开启 按钮。将触发器设置设置为外部触发器。单击 "退出 "按钮以退出 WIM 程序。</li>
		<li>使用步骤 2.4 收集 A 线信号。打开激光挡板。按照步骤 2.6\u20122.7 对齐。对齐后按 停止 以结束收集。</li>
		<li>选择 RIM 程序。命名新创建的文件夹。单击 "收集 "按钮开始扫描。</li>
		<li>单击 "停止" 按钮以在完成获取后结束扫描。单击 "退出 "按钮以退出 RIM 程序。</li>
		<li>成像结束时使用宫颈脱位对动物实施安乐死。</li>
	</ol></li>
	<li>进行血管可视化的 WIM。<ol>
<li>使用聚焦超声波传感器（中央频率:25 MHz:带宽:90%以上:焦距:8毫米）。去除老鼠耳朵或头皮的头发。<ol>
<li>使用手术刀在鼠标颅骨时间顶部的横向侧面（深入到头骨）上做一个小切口。使用眼科剪刀从此切口开始。切开头骨外侧的头皮。压缩出血点以止血。用普通盐水清洗伤口。将鼠标放在支架上。</li>
		</ol>
</li>
		<li>使用超声波凝胶使成像区域与聚乙烯膜接触。避免接触区域的气泡（补充图 1）。</li>
		<li>将支架放在工作台上进行声学耦合。使用步骤 2.3=u20122.4 打开激光并收集 A 线信号。使用步骤 2.6\u20122.7 对齐。对齐后按 停止 以结束收集。</li>
		<li>选择WIM程序。命名新创建的文件夹。在"扫描速度"选项卡中将扫描参数设置为"10 mm/s"，在"扫描区域"选项卡下将扫描参数设置为"10 mm*10 毫米"，在"步骤"选项卡中将扫描参数设置为"10 mm/s"。单击 "收集 "按钮开始扫描。</li>
		<li>单击 "停止" 按钮以在完成获取后结束扫描。单击 返回为零 ，使电机返回为零。单击 "退出 "按钮以退出 WIM 程序。</li>
		<li>在动物仍在麻醉期间，在手术结束时对动物实施安乐死。</li>
	</ol></li>
	<li>进行RIM对小动物进行动态监测。<ol>
<li>剃老鼠腹部的头发。将鼠标放在支架上处于超平位置。</li>
		<li>使用超声波凝胶使成像区域与聚乙烯膜接触。避免接触区域中的气泡。</li>
		<li>将支架放在工作台上进行声学耦合。执行步骤 2.3=u20122.4 启动激光并收集 A 线信号。执行步骤 2.6=u20122.7 以对齐。对齐后按 停止 以结束收集。</li>
		<li>选择 RIM 程序。命名新创建的文件夹。单击 "收集 "按钮开始扫描。</li>
		<li>单击 "停止" 按钮以在完成获取后结束扫描。单击 "退出 "按钮以退出 RIM 程序。</li>
	</ol></li>
	<li>使用 RIM 数据，通过用户定义的程序沿深度方向重建最大振幅投影 （MAP）。观察动物的动态变化。</li>
</ol>

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所有动物实验均按照机构动物护理和使用委员会批准的准则和条例进行。作者在手稿中没有相关的经济利益，也没有其他潜在的利益冲突可以披露。

在这里，我们提出了一个双栅格扫描光声小动物成像仪非侵入性血管可视化，这是设计和开发，以捕捉血管结构和相关的血液动态变化。DRS-PAI 的优点是将 WIM 和 RIM 集成到一个系统中，从而更容易研究小动物的血管动态和血管网络结构。该系统可提供高分辨率广域血管可视化和实时血液动力学。
在目前的系统中，光激发采用单波长光源实现。未来的多波长系统将提供其他参数，如血氧饱和度。此外，还可以开发一种特殊的图像处理算法进行定量分析，包括估计血管直径、血管密度、血管结肠等。定量分析可以为疾病的早期诊断和治疗提供有价值的信息。
总之，该系统使研究人员能够获得具有生物医学相关性的小动物研究的高维生理学和病理学见解。该系统可适应大多数小动物研究环境，包括但不限于血管生成成像、肿瘤微环境、血液动力学、大脑功能连接、微循环、药物反应和治疗反应。协议中的关键步骤包括双扫描结构的设计、WIM 中光学和声学焦点的共生调整以及 RIM 声场的中心点调整。

在基础生物医学领域，小动物可以模拟人类的生理功能。因此，小动物成像在指导人类同源性疾病研究、寻求有效治疗等方面起着重要作用。光声成像 （PAI） 是一种非侵入性成像技术，结合了光学成像和超声成像2的优点。光声显微镜（PAM）是小动物3的基础研究的宝贵成像方法。PAM可以根据光学激发和超声波检测4轻松获得高分辨率、深渗透、高特异性和高对比度图像。
具有特定波长的脉冲激光被组织内源性色谱吸收。随后，组织温度升高，导致产生光诱发的超声波。超声波可以通过超声波传感器检测。经过信号采集和图像重建，吸收器的空间分布可达到5.一方面，全器官血管网络的可视化需要广阔的视野。广域扫描过程通常需要很长时间才能确保高分辨率6，7，8。另一方面，观察小动物的血动力学活动需要快速的实时成像。实时成像有利于实时研究小动物的生命体征9、10、11。实时成像的视野通常足够小，以确保较高的更新率。因此，在实现广阔的视野和实时成像之间往往存在权衡。以前，两个不同的系统分别用于广域成像或实时成像。
这项工作报告了双栅格扫描光声成像仪 （DRS-PAI），它集成了基于二维机动转换阶段的广域成像和基于双轴电表扫描仪的实时成像。进行宽场成像模式 （WIM） 以显示血管形态。对于实时成像模式 （RIM），目前有两个功能。首先，RIM 可以提供实时 B 扫描图像。通过测量沿深度方向的血管位移，可以揭示呼吸或脉搏的特征。其次，RIM 可以定量测量 WIM 图像中的特定区域。通过提供当地 WIM 区域的可比图像，可以准确显示当地变化的细节。该系统在血管可视化的广域成像和局部动态的实时成像之间设计了灵活的过渡。该系统在基础生物医学研究中是可取的，因为那里需要小动物成像。

<table><tbody><tr><td>12 bit multi-purpose digitizer</td><td>Spectrum</td><td>M3i.3221</td><td>Data acquisition card</td></tr><tr><td>A-line collected program</td><td>National Instrument</td><td>LabVIEW</td><td>User-defined program</td></tr><tr><td>Amplifier</td><td>RF Bay</td><td>LNA-650</td><td>Amplifier</td></tr><tr><td>Depilatory Cream</td><td>Veet</td><td>33-II</td><td>Animal depilatory</td></tr><tr><td>Fiberport Coupler</td><td>Thorlab</td><td>PAF-X-7-A</td><td>Fiber Coupler</td></tr><tr><td>Field Programmable Gate Array</td><td>Altera</td><td>Cyclone IV</td><td>Trigger Control</td></tr><tr><td>Fixed Focus Collomation Packages</td><td>Thorlabs</td><td>F240FC-532</td><td>Fiber Collimator</td></tr><tr><td>Foused ultrasonic transducer</td><td>Self-made</td><td></td><td></td></tr><tr><td>Graphics Processing Unit</td><td>NVIDIA</td><td>GeForce GTX 1060</td><td>Processing data</td></tr><tr><td>Holder</td><td>Self-made</td><td></td><td>Animal fixation</td></tr><tr><td>Laser control program</td><td>National Instrument</td><td>LabVIEW</td><td>User-defined program</td></tr><tr><td>Mice</td><td>Guangdong Medical Laboratory Animal Center</td><td>BALB/c</td><td>Animal Model</td></tr><tr><td>Microscope camera</td><td>Mshot</td><td>MS60</td><td>CCD camera</td></tr><tr><td>Microscope Objective</td><td>Daheng Optics</td><td>GCO-2111</td><td>Objective Lens</td></tr><tr><td>Mirror</td><td>Daheng Optics</td><td>GCC-1011</td><td>Moveable/Fixed Mirror</td></tr><tr><td>Moving Magnet Capacitive Detector Galvanometer Scanner</td><td>Century Sunny</td><td>S8107</td><td>real-time scanner</td></tr><tr><td>Mshot image analysis system</td><td>Mshot</td><td></td><td>Display software</td></tr><tr><td>Normal Saline</td><td>CR DOUBLE-CRANE</td><td>H34023609</td><td>Normal Saline</td></tr><tr><td>Ophthalmic Scissors</td><td>SUJIE</td><td></td><td>Scalp Remove</td></tr><tr><td>Planar ultrasonic transducer</td><td>Self-made</td><td></td><td></td></tr><tr><td>Plastic Wrap</td><td>HJSJLSL</td><td></td><td>Polyethylene Membrane</td></tr><tr><td>Program Control Software</td><td>National Instrument</td><td>LabVIEW</td><td>User-defined Program</td></tr><tr><td>Pulsed Q-swithched Laser</td><td>Laser-export</td><td>DTL-314QT</td><td>532-nm pulse Laser</td></tr><tr><td>Real-time imaging program</td><td>National Instrument</td><td>LabVIEW</td><td>User-defined program</td></tr><tr><td>Ring-shaped white LED</td><td>Self-made</td><td></td><td></td></tr><tr><td>Shaver</td><td>Codos</td><td>CP-9200</td><td>Animal Shaver</td></tr><tr><td>Single-Mode Fibers</td><td>Nufern</td><td>460-HP</td><td>Single-mode fiber</td></tr><tr><td>Surgical Blade</td><td>SUJIE</td><td>11</td><td>Blade</td></tr><tr><td>Surgical Scalpel</td><td>SUJIE</td><td>7</td><td>Scalp Remove</td></tr><tr><td>Translation Stage</td><td>Jiancheng Optics</td><td>LS2-25T</td><td>wide-field scanning stage</td></tr><tr><td>Ultrasonic Transducer</td><td>Self-made</td><td></td><td></td></tr><tr><td>Ultrasound gel</td><td>GUANGGONG PAI</td><td>ZC4252418</td><td>Acoustic Coupling</td></tr><tr><td>Urethane</td><td>Tokyo Chemical Industry</td><td>C0028</td><td>Animal Anestheized</td></tr><tr><td>Water tank</td><td>Self-made</td><td></td><td></td></tr><tr><td>Wide-field imaging program</td><td>National Instrument</td><td>LabVIEW</td><td>User-defined program</td></tr><tr><td>XY Translator Mount</td><td>Self-made</td><td></td><td></td></tr></tbody></table>

dual raster-scanning photoacoustic small-animal imager for vascular visualization

小动物血管网络成像在基础生物医学研究中发挥了重要作用。光声成像技术在小动物影像学中具有巨大的应用潜力。小型动物的广域光声成像可以提供具有高空间分辨率、深度渗透和多重对比度的图像。此外，实时光声成像系统可观测小动物血管的血动力学活动，可用于研究小动物生理特征的动态监测。在这里，展示了一个双栅格扫描光声成像仪，具有可切换的双模成像功能。广域成像由二维机动转换阶段驱动，而实时成像则由电表实现。通过设置不同的参数和成像模式，可以进行小动物血管网络的体内可视化。实时成像可用于观察药物引起的脉搏变化和血流量变化等。广域成像可用于跟踪肿瘤血管的生长变化。这些在基础生物医学研究的各个领域都很容易被采用。

DRS-PAI 的示意图显示在 图 1中。该系统允许WIM与RIM之间灵活且可重复的切换。收购的 PA 信号处理得很快，以生成 PA B 扫描和 MAP 图像。CCD 相机可以提供样品的照片。
DRS-PAI 的所有组件均集成并组装在成像仪设置中（图 2），便于组装和操作。在 WIM 中，使用二维机动阶段的连续栅格扫描。记录运行阶段的信号。数据采集是在统一翻译阶段进行。在 RIM 中，使用了双轴电镀锌仪扫描仪。数据与加尔瓦扫描同步收集（图3）。
在这里，收集了每个成像模式的样本的血管图像。 图 4A 显示鼠标在 WIM 中的 MAP 图像。成像时间大约是33分钟。 图4B 显示了RIM期间鼠标的B扫描图像。RIM的整个过程显示在 视频1中。然后，使用了聚焦超声波传感器。小鼠耳朵和大脑的血管网络显示在 图5中。成像时间大约是16分钟。这显示了 DRS-PAI 对广域血管进行成像的能力。此外， 图 6A 显示成像范围包含一个容器。RIM 的成像范围约为 100μm，因为使用了聚焦超声波传感器。小鼠腹部深度方向与时间的位移图像显示在 图 6B中。 视频 2 显示血管位移和获取当前脉搏或呼吸曲线的过程。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/61584/61584fig01.jpg"> 图1:DRS-PAI系统的示意图。<a href="https://www.jove.com/files/ftp_upload/61584/61584fig01large.jpg" target="_blank">请点击这里查看此数字的较大版本。</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/61584/61584fig02.jpg"> 图2:DRS-PAI系统的设计。 （A） DRS-PAI系统的照片。（B） 面板显示激光路径组装设置的照片。（C） 面板显示激光路径组装的3D模型。（D） 面板显示双轴快速电表扫描仪组件。（E） 面板显示探头组件。（F） 面板显示CCD光学路径组件。 <a href="https://www.jove.com/files/ftp_upload/61584/61584fig02large.jpg" target="_blank">请点击这里查看此数字的较大版本。</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/61584/61584fig03.jpg"> 图3:设置不同成像模式的扫描。 （A） WIM的扫描路径。（B） RIM的扫描路径。（C） 两种成像模式的触发设置。 <a href="https://www.jove.com/files/ftp_upload/61584/61584fig03large.jpg" target="_blank">请点击这里查看此数字的较大版本。</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/61584/61584fig04.jpg"> 图4:鼠标背面的光声WIM和RIM。 （A） 鼠标的 MAP 图像回到 WIM 中。（B） 在 RIM 中鼠标的 B 扫描图像。 <a href="https://www.jove.com/files/ftp_upload/61584/61584fig04large.jpg" target="_blank">请点击这里查看此数字的较大版本。</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/61584/61584fig05.jpg"> 图5:鼠标的光声WIM。 （A） WIM中鼠标耳朵的地图图像。（B） WIM中鼠脑的地图图像。 <a href="https://www.jove.com/files/ftp_upload/61584/61584fig05large.jpg" target="_blank">请点击这里查看此数字的较大版本。</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/61584/61584fig06.jpg"> 图6:小鼠腹部的光声 RIM 。 （A） RIM中鼠标腹部的B扫描图像。（B） 沿鼠标腹部深度方向与 RIM 中的时间的 MAP 图像。 <a href="https://www.jove.com/files/ftp_upload/61584/61584fig06large.jpg" target="_blank">请点击这里查看此数字的较大版本。</a>
视频1:鼠标返回的RIM过程。<a href="https://cloudflare.jove.com/files/ftp_upload/61584/Video1.mp4" target="_blank">请点击这里下载此视频。</a>
视频2:MAP图像沿鼠标腹部深度方向与时间的过程。<a href="https://cloudflare.jove.com/files/ftp_upload/61584/Video2.mp4" target="_blank">请点击这里下载此视频。</a>
补充图1:与聚乙烯膜接触的成像区域部分。<a href="https://cloudflare.jove.com/files/ftp_upload/61584/61584supfig01.jpg" target="_blank">请点击这里下载此数字。</a>

Watch this Scientific Journal Video about Dual Raster-Scanning Photoacoustic Small-Animal Imager for Vascular Visualization at JoVE.com

Dual Raster-Scanning Photoacoustic Small-Animal Imager for Vascular Visualization

设计了双栅格扫描光声成像仪，集成了广域成像和实时成像。

用于血管可视化的双栅格扫描光声小动物成像仪

Imaging of vascular networks on small animals has played an important role in basic biomedical research. Photoacoustic imaging technology has great ...

dual-raster-scanning-photoacoustic-small-animal-imager-for-vascular

Nanyang Technological University

Research

JoVE Journal

Bioengineering

4.0K 次观看.  South China Normal University. 设计了双栅格扫描光声成像仪，集成了广域成像和实时成像。

视频: Dual Raster-Scanning Photoacoustic Small-Animal Imager for Vascular Visualization

Three-dimensional Optical-resolution Photoacoustic Microscopy

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. 
The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)1, where the optical irradiation is focused to the diffraction limit to achieve cellular1 or even subcellular2 level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy3 or with optical-scattering-based OCT4 (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. 
Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology5, 6, ophthalmology7, 8, vascular biology9, and dermatology10. In this video, we teach the system configuration and alignment of OR-PAM as well as the experimental procedures for in vivo functional microvascular imaging.

Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.

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

Photoacoustic Cystography

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The risk of bladder cancers in children due to radiation exposure is more significant than many other cancers. Here we demonstrate the feasibility of nonionizing and noninvasive photoacoustic (PA) imaging of urinary bladders, referred to as photoacoustic cystography (PAC), using near-infrared (NIR) optical absorbents (i.e. methylene blue, plasmonic gold nanostructures, or single walled carbon nanotubes) as an optical-turbid tracer. We have successfully imaged a rat bladder filled with the optical absorbing agents using a dark-field confocal PAC system. After transurethral injection of the contrast agents, the rat's bladders were photoacoustically visualized by achieving significant PA signal enhancement. The accumulation was validated by spectroscopic PA imaging. Further, by using only a laser pulse energy of less than 1 mJ/cm2 (1/20 of the safety limit), our current imaging system could map the methylene-blue-filled-rat-bladder at the depth of beyond 1 cm in biological tissues in vivo. Both in vivo and ex vivo PA imaging results validate that the contrast agents were naturally excreted via urination. Thus, there is no concern regarding long-term toxic agent accumulation, which will facilitate clinical translation.

Photoacoustic cystography (PAC) has a great potential to map urinary bladders, a radiation sensitive internal organ in pediatric patients, without using any ionizing radiation or toxic contrast agent. Here we demonstrate the use of PAC for mapping urinary bladders with an injection of optical-opaque tracers in rats in vivo.

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 ...

Novel Photoacoustic Microscopy and Optical Coherence Tomography Dual-modality Chorioretinal Imaging in Living Rabbit Eyes

Photoacoustic ocular imaging is an emerging ophthalmic imaging technology that can noninvasively visualize ocular tissue by converting light energy into sound waves and is currently under intensive investigation. However, most reported work to date is focused on the imaging of the posterior segment of the eyes of small animals, such as rats and mice, which poses challenges for clinical human translation due to small eyeball sizes. This manuscript describes a novel photoacoustic microscopy (PAM) and optical coherence tomography (OCT) dual-modality system for posterior segment imaging of the eyes of larger animals, such as rabbits. The system configuration, system alignment, animal preparation, and dual-modality experimental protocols for in vivo, noninvasive, label-free chorioretinal imaging in rabbits are detailed. The effectiveness of the method is demonstrated through representative experimental results, including retinal and choroidal vasculature obtained by the PAM and OCT. This manuscript provides a practical guide to reproducing the imaging results in rabbits and advancing photoacoustic ocular imaging in larger animals.

This manuscript describes the novel setup and operating procedure of a photoacoustic microscopy and optical coherence tomography dual-modality system for noninvasive, label-free chorioretinal imaging of larger animals, such as rabbits.

新型光声显微镜与光学相干层析成像在活兔眼中的双模脉络成像

Photoacoustic ocular imaging is an emerging ophthalmic imaging technology that can noninvasively visualize ocular tissue by converting light energy into ...

工程学

Non-invasive Parenchymal, Vascular and Metabolic High-frequency Ultrasound and Photoacoustic Rat Deep Brain Imaging

Photoacoustics and high frequency ultrasound stands out as powerful tools for neurobiological applications enabling high-resolution imaging on the central nervous system of small animals. However, transdermal and transcranial neuroimaging is frequently affected by low sensitivity, image aberrations and loss of space resolution, requiring scalp or even skull removal before imaging. To overcome this challenge, a new protocol is presented to gain significant insights in brain hemodynamics by photoacoustic and high-frequency ultrasounds imaging with the animal skin and skull intact. The procedure relies on the passage of ultrasound (US) waves and laser directly through the fissures that are naturally present on the animal cranium. By juxtaposing the imaging transducer device exactly in correspondence to these selected areas where the skull has a reduced thickness or is totally absent, one can acquire high quality deep images and explore internal brain regions that are usually difficult to anatomically or functionally describe without an invasive approach. By applying this experimental procedure, significant data can be collected in both sonic and optoacoustic modalities, enabling to image the parenchymal and the vascular anatomy far below the head surface. Deep brain features such as parenchymal convolutions and fissures separating the lobes were clearly visible. Moreover, the configuration of large and small blood vessels was imaged at several millimeters of depth, and precise information were collected about blood fluxes, vascular stream velocities and the hemoglobin chemical state. This repertoire of data could be crucial in several research contests, ranging from brain vascular disease studies to experimental techniques involving the systemic administration of exogenous chemicals or other objects endowed with imaging contrast enhancement properties. In conclusion, thanks to the presented protocol, the US and PA techniques become an attractive noninvasive performance-competitive means for cortical and internal brain imaging, retaining a significant potential in many neurologic fields.

The present work describes a new protocol to perform non-invasive high-frequency ultrasound and photoacoustic based imaging on rat brain, to efficiently visualize deep subcortical regions and their vascular patterns by directing signals on skull foramina naturally present on animal cranium.

非侵入性的脑实质，血管和代谢高频超声和光声大鼠深脑成像

Photoacoustics and high frequency ultrasound stands out as powerful tools for neurobiological applications enabling high-resolution imaging on the central ...

神经科学

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

Photoacoustic microscopy (PAM) is a fast-growing invivo imaging modality that combines both optics and ultrasound, providing penetration beyond the optical mean free path (~1 mm in skin) with high resolution. By combining optical absorption contrast with the high spatial resolution of ultrasound in a single modality, this technique can penetrate deep tissues. Photoacoustic microscopy systems can have either a low acoustic resolution and probe deeply or a high optical resolution and probe shallowly. It is challenging to achieve high spatial resolution and large depth penetration with a single system. This work presents an AR-OR-PAM system capable of both high-resolution imaging at shallow depths and low-resolution deep-tissue imaging of the same sample in vivo. A lateral resolution of 4 &#181;m with 1.4 mm imaging depth using optical focusing and a lateral resolution of 45 &#181;m with 7.8 mm imaging depth using acoustic focusing were successfully demonstrated using the combined system. Here,&#160;in vivo&#160;small-animal blood vasculature imaging is performed to demonstrate its biological imaging capability.

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

Here a switchable acoustic resolution (AR) and optical resolution (OR) photoacoustic microscopy (AR-OR-PAM) system capable of both high resolution imaging at shallow depth and low resolution deep tissue imaging on the same sample in vivo is demonstrated.

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

In vivo small-animal imaging has an important role to play in preclinical studies. Photoacoustic tomography (PAT) is an emerging hybrid imaging modality that shows great potential for both preclinical and clinical applications. Conventional optical parametric oscillator-based PAT (OPO-PAT) systems are bulky and expensive and cannot provide high-speed imaging. Recently, pulsed-laser diodes (PLDs) have been successfully demonstrated as an alternative excitation source for PAT. Pulsed-laser diode PAT (PLD-PAT) has been successfully demonstrated for high-speed imaging on photoacoustic phantoms and biological tissues. This work provides a visualized experimental protocol for in vivo brain imaging using PLD-PAT. The protocol includes the compact PLD-PAT system configuration and its description, animal preparation for brain imaging, and a typical experimental procedure for 2D cross-sectional rat brain imaging. The PLD-PAT system is compact and cost-effective and can provide high-speed, high-quality imaging. Brain images collected in vivo at various scan speeds are presented.

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

A compact pulsed-laser diode-based photoacoustic tomography (PLD-PAT) system for high-speed in vivo brain imaging in small animals is demonstrated.

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 ...

Hand-held Clinical Photoacoustic Imaging System for Real-time Non-invasive Small Animal Imaging

Translation of photoacoustic imaging into the clinic is a major challenge. Handheld real-time clinical photoacoustic imaging systems are very rare. Here, we report a combined photoacoustic and clinical ultrasound imaging system by integrating an ultrasound probe with light delivery for small animal imaging. We demonstrate this by showing sentinel lymph node imaging in small animals along with minimally invasive real-time needle guidance. A clinical ultrasound platform with access to raw channel data allows the integration of photoacoustic imaging leading to a handheld real-time clinical photoacoustic imaging system. Methylene blue was used for sentinel lymph node imaging at 675 nm wavelength. Additionally, needle guidance with dual modal ultrasound and photoacoustic imaging was shown using the imaging system. Depth imaging of up to 1.5 cm was demonstrated with a 10 Hz laser at a photoacoustic imaging frame rate of 5 frames per second.

A clinical handheld photoacoustic imaging system will be demonstrated for real-time non-invasive small animal imaging.

手持式实时非侵入性小动物成像的临床光声成像系统

Translation of photoacoustic imaging into the clinic is a major challenge. Handheld real-time clinical photoacoustic imaging systems are very rare. Here, ...

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

Photoacoustic (PA) tomography (PAT) imaging is an emerging biomedical imaging modality useful in various preclinical and clinical applications. Custom-made circular ring array-based transducers and conventional bulky Nd:YAG/OPO lasers inhibit translation of the PAT system to clinics. Ultra-compact pulsed laser diodes (PLDs) are currently being used as an alternative source of near-infrared excitation for PA imaging. High-speed dynamic in vivo imaging has been demonstrated using a compact PLD-based desktop PAT system (PLD-PAT). A visualized experimental protocol using the desktop PLD-PAT system is provided in this work for dynamic in vivo brain imaging. The protocol describes the desktop PLD-PAT system configuration, preparation of animal for brain vascular imaging, and procedure for dynamic visualization of indocyanine green (ICG) dye uptake and clearance process in rat cortical vasculature.&#160;

A compact pulsed laser diode-based desktop photoacoustic tomography (PLD-PAT) system is demonstrated for high-speed dynamic in vivo imaging of small animal 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

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

Multispectral Optoacoustic Tomography for Functional Imaging in Vascular Research

Microcirculatory impairment has been recognized in various disease processes, underlying this growing theme within vascular research. In recent years, the development of live imaging systems has set the (analytical) pace in both basic and clinical research, with the objective of creating new instruments capable of providing real-time, quantifiable endpoints with clinical interest and application. Near-infrared spectroscopy (NIRS), positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) are available, among other techniques, but cost, image resolution, and reduced contrast are recognized as common challenges. Optoacoustic tomography (OT) offers a new perspective on vascular functional imaging, combining state-of-the-art optical absorption and spatial resolution capacities (from micrometer optical to millimeter acoustic resolution) with tissue depth. In this study, we tested the applicability of multispectral optoacoustic tomography (MSOT) for functional imaging. The system uses a tunable optical parametric oscillator (OPO) pumped by an Nd: YAG laser, providing excitation pulses sensed by a 3D probe at wavelengths from 680 nm to 980 nm. Images obtained from the human forearm were reconstructed through a specific algorithm (supplied within the manufacturer&#39;s software) based on the response of specific chromophores. Maximal Oxygenated Hemoglobin (Max HbO2) and Deoxygenated Hemoglobin (Max Hb), Total Hemoglobin (HbT), and mean Oxygen Saturation (mSO2) to vascular density (&#181;Vu), inter-unit average distances (&#950;Ad), and capillary blood volume (mm3) may be measured using this system. The applicability potential found with this OT system is relevant. Ongoing software developments will surely improve the utility of this imaging system.

The present protocol describes the acquisition of multispectral optoacoustic images of in vivo human skin vasculature. These include the quantification of hemoglobin and melanin, regarded as chromophores of interest for functional analysis.

用于血管研究功能成像的多光谱光声断层扫描

Microcirculatory impairment has been recognized in various disease processes, underlying this growing theme within vascular research. In recent years, the ...

缺血性卒中的无创综合 PAUSAT 全脑成像

Integrated Photoacoustic, Ultrasound, and Angiographic Tomography (PAUSAT) for NonInvasive Whole-Brain Imaging of Ischemic Stroke

Presented here is an experimental ischemic stroke study using our newly developed noninvasive imaging system that integrates three acoustic-based imaging technologies: photoacoustic, ultrasound, and angiographic tomography (PAUSAT). Combining these three modalities helps acquire multi-spectral photoacoustic tomography (PAT) of the brain blood oxygenation, high-frequency ultrasound imaging of the brain tissue, and acoustic angiography of the cerebral blood perfusion. The multi-modal imaging platform allows the study of cerebral perfusion and oxygenation changes in the whole mouse brain after stroke. Two commonly used ischemic stroke models were evaluated: the permanent middle cerebral artery occlusion (pMCAO) model and the photothrombotic (PT) model. PAUSAT was used to image the same mouse brains before and after a stroke and quantitatively analyze both stroke models. This imaging system was able to clearly show the brain vascular changes after ischemic stroke, including significantly reduced blood perfusion and oxygenation in the stroke infarct region (ipsilateral) compared to the uninjured tissue (contralateral). The results were confirmed by both laser speckle contrast imaging and triphenyltetrazolium chloride (TTC) staining. Furthermore, stroke infarct volume in both stroke models was measured and validated by TTC staining as the ground truth. Through this study, we have demonstrated that PAUSAT can be a powerful tool in noninvasive and longitudinal preclinical studies of ischemic stroke.

作者聚焦：用于缺血性卒中的无创全脑成像的集成光声、超声和血管造影断层扫描 （PAUSAT）  

This work demonstrates the use of a multimodal ultrasound-based imaging platform for noninvasive imaging of ischemic stroke. This system allows for the quantification of blood oxygenation through photoacoustic imaging and impaired perfusion in the brain through acoustic angiography.

集成光声、超声和血管造影断层扫描 （PAUSAT） 用于缺血性卒中的无创全脑成像

Presented here is an experimental ischemic stroke study using our newly developed noninvasive imaging system that integrates three acoustic-based imaging ...

用于血管可视化的双栅格扫描光声小动物成像仪

摘要

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三维光学分辨率的光声显微镜

光声膀胱造影

新型光声显微镜与光学相干层析成像在活兔眼中的双模脉络成像

非侵入性的脑实质，血管和代谢高频超声和光声大鼠深脑成像

可切换声光学分辨率光声显微镜

高性能紧凑型光声层析成像系统

手持式实时非侵入性小动物成像的临床光声成像系统

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

用于血管研究功能成像的多光谱光声断层扫描

集成光声、超声和血管造影断层扫描（PAUSAT）用于缺血性卒中的无创全脑成像

用于血管可视化的双栅格扫描光声小动物成像仪

摘要

探索更多视频

此视频中的章节

三维光学分辨率的光声显微镜

光声膀胱造影

新型光声显微镜与光学相干层析成像在活兔眼中的双模脉络成像

非侵入性的脑实质，血管和代谢高频超声和光声大鼠深脑成像

可切换声光学分辨率光声显微镜

高性能紧凑型光声层析成像系统

手持式实时非侵入性小动物成像的临床光声成像系统

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

用于血管研究功能成像的多光谱光声断层扫描

集成光声、超声和血管造影断层扫描 （PAUSAT） 用于缺血性卒中的无创全脑成像

集成光声、超声和血管造影断层扫描（PAUSAT）用于缺血性卒中的无创全脑成像