We are very grateful for the financial support of the Physics Department of CINVESTAV. We also want to thank our technician Marcos Fontaine Sanchez for his remarkable assistance with the set up. Thanks a lot to Sarah LaPointe for reviewing the English-language of this document.

1.制备PET的安装程序<ol><li>准备PMT的加上塑料闪烁体片。根据其种类的PMT（大小，光电阴极的形状）的建立一个适当的闪烁体片，以适应与PMT的光电阴极。 <ol><li>裹闪烁体块用黑色胶带。离开一侧揭露的，因为它会被加上的PMT光入射。 注:重要的是，这些作品都是以前抛光，以避免光积累的损失。 </li></ol></li><li>清洁的PMT光入射与醇（70％的商业酒精浓度）然后应用光学润滑脂它和闪烁体的未覆盖的面。加上光电倍增管面的闪烁体，并与更多的黑色胶带包装他们。 <ol><li>光电倍增管连接到源电压（一个电缆被包括为每个PMT，在这种情况下，偏压14V的偏压和0.5伏电压控制）。识别通过连接从PMT的信号来PMT信号电缆连接到一个标准数字示波器通道（一个信号电缆还包括用于每一个光电倍增管）。转弯时的开/关在实验室中的光观察的变化的信号的振幅，以验证不存在光损失。重复每个四个探测器，在此步骤，其中一个检测器装置，闪烁体加的PMT。 </li></ol></li><li>通过将一个检测器的闪烁器部分上面另一个检测器的相应部分建立一个巧合系统。把所谓的鉴别和逻辑单元模块两个NIM（核仪器模块）仪器在NIM箱子。 </li><li>连接从检测器的输出信号到一个鉴别器模块的输入端。段中的与模式使用一个逻辑单元中，通过选择这样的逻辑的情况下，在逻辑单元的前面板。连接两个鉴别器输出的逻辑单元输入。 注:和的是，选择当两个平方信号到达同一时间或在重合的逻辑运算。 </li><li>有限公司nnect在定标器模块中的逻辑单元的输出信号（此信号计数数字信号）来计算的事件（由宇宙射线击中巧合两个探测器创建）。 </li></ol> 2.获取与PET信号<ol><li>将两个探测器在之前定义的方形区域的对角，所以他们面对对方，20厘米外，并做同样的练习为1.4和1.5，但是这一次，而不是使用宇宙射线（宇宙射线担任临时天然放射源），使用的Na-22辐射源。 <ol><li>将放射源在两个探测器之间的中距离，并通过了定标器模块进行数据采集。系统设置和用于获得巧合的逻辑块的概略结构可在图1，2和 3中看到 。 </li></ol></li><li>通过连接两个判别PMT的输出和测量到达信号的时间差符合输出在示波器。每三个信号的进入示波器输入;将有三个方波信号的示波器屏幕。与水平刻度（时间刻度）测量两个判别信号的时间差。 注意:当放射源是直接在两个检测器之间的中间会有很少或正方形之间没有分离或时间差鉴别信号的平均值，并且当放射性源离开该中心，并靠近一个PMT的再将有平均时间差。 </li><li>发送这些定时信号提供给八个通道的CAMAC（计算机测量和控制）的TDC（时间 - 数字转换器）模块中的一个。要做到这一点，连接的逻辑与贸发局的输入输出所谓的"开始"，然后连接探测器区分输出到TDC输入这是所谓的"STOP"。该和信号必须通过延迟冒顿被推迟乐在为了某些纳秒这个信号，另外两个STOP信号之前到达（ 见图 4）。 </li><li>校准TDC计数单位之间的时间通过一个软件程序，显示示波器（详见第3步）。通过使用放射性源和探测器中的一个之间的距离间隔，测量每个位置的平均时间差（步骤2.3）这样做校准。通过标准总线GPIB（通用仪器总线）这样做标定，建立不同的模块和计算机之间的软件通信。 </li></ol> 3.构建虚拟仪器接口<ol><li>下载并使用LabVIEW软件或任何类似的软件。 注意:要使用LabVIEW工作，就必须有"G编程语言"的一些知识。在这种语言中，没有代码已被写入，所有执行的操作可以从一个软件工具苍白来完成TTE。一个简单的指南与实际的例子可以在工具的帮助中找到。 </li><li>选择前面板工具选项板阵列实用程序（程序变量容器）来保存TDC输出数据。 注意:"前面板"是虚拟仪器给用户和"框图"的图形接口用于软件编程。 </li><li>绘制数据采集（从上止点时的数据），通过选择地块菜单逻辑工具。找出与该源的每个位置相关的情节数据。由一些厘米，从不同的探测器行源距离执行此操作。 </li><li>取使用统计函数（平均值）从数学菜单工具的数据的平均值，并选择集中在平均值的间隔。然后，根据该编程逻辑随后，使用从阵列菜单必要的工具以删除所有的数据与该间隔之外的值。 </li><li>从日选择指标Ë框图工具板，以显示存储的每个阵列中的数据的数目，并确定一些容器具有最大数目的存储数据。 </li><li>获取数据的平均值在3.5步选择的每个阵列中，并利用这些信息建立了一整套的时间间隔值，使用该LabVIEW程序框图工具选项板中的每个源位置。 </li><li>选择的指标从面板工具调色板一个数组来存储在步骤3.6的测量值的序列中得到的平均值。 </li><li>从框图工具选项板的情况下的结构关系每个位置，其步骤3.7各区间，每个区间关联到一个虚拟的前面板工具面板的LED阵列。 </li><li>注意，每个信号取到达到TDC信道的时间:当放射源从中间移近一个检测器，观察LED的编程阵列（ 参见图5中的虚拟源的移动</stro纳克&gt;）向右移动在计算机中。 </li><li>包括前面板工具选项板的总时间采集控制（可变编程元素）。 注:所述定位的效率将取决于这个控制时间工具:越时间采集需要时，更精确地模拟放射源的虚拟对象将给出正确的位置。 </li></ol> 4.图形结果<ol><li>为了校准的目的，将源在任何中间位置相对于耦合对检测器中的一个。进行测量30分钟，并与数据获取的，采取累计每2分钟的值的平均值。重复此过程，对于不同的源位置和绘制在所有位置从每个检测器的平均值（ 参见图6和7）。的探测器值的差异绘制在图8。 </li><li>为了获得更好的地区环境部门一道LTS，选择两个检测器具有类似的数据值，形成一对夫妇。为了测试这一点，把PMT的控制电压到其较低的值，在这种情况下，为0.5V开始由检测器输出连接到定标器输入测量用一个固定的时间定标器模块检测到的事件的数量。增加0.01伏电压，再次测量。重复此过程，以达到最大可能的控制值，在这种情况下，0.9V。 <ol><li>绘制检测到的事件与半对数刻度的控制电压的值 （见图9）。夫妇有相似的分布探测器对。 </li></ol></li><li>为了测试该系统的灵敏度，将在沿行一些等间距的中间位置的放射性源，在这种情况下有五个。采集数据5分钟，在每一个位置上，并独立地绘制的每个检测器获得的值的平均值和中值（见图10和11）。 </li></ol>

<ol><li>Cerello, P., Pennazio, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+innovative+detector+concept+for+hybrid+4D-PET%2FMRI%5BTitle%5D)+AND+%22Imaging.+Nucl.+Instr.+Meth.+Phys.+Res%22%5BJournal%5D)">An innovative detector concept for hybrid 4D-PET/MRI.</a> Imaging. Nucl. Instr. Meth. Phys. Res. 702, 1-3 (2013).</li>
<li>Muehllerher, G., Karp, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Positron+tomography+emission%5BTitle%5D)+AND+%22Phys.+Med.+Biol%22%5BJournal%5D)">Positron tomography emission.</a> Phys. Med. Biol. 51, R117-R137 (2006).</li>
<li>Conti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((State+of+the+art+and+challenges+of+time+of+flight+PET%5BTitle%5D)+AND+%22Physica+Medica%22%5BJournal%5D)">State of the art and challenges of time of flight PET.</a> Physica Medica. 25 (1), 1-11 (2008).</li>
<li>Abreu, Y., Piñera, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Simulation+of+a+PET+system+and+study+of+some+geometry+parameters%5BTitle%5D)+AND+%22AIP+conference%22%5BJournal%5D)">Simulation of a PET system and study of some geometry parameters.</a> AIP conference. 1032, 219-221 (2008).</li>
<li>Langner, J. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=%22Development+of+a+parallel+Computing+optimized+head+movement+correction+method+in+PET%22">Development of a parallel Computing optimized head movement correction method in PET</a>. , University of Applied Sciences in Dresden. Saxony, Germany. (2003).</li>
<li>Budinger, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Time-of-flight+PET%5BTitle%5D)+AND+%22J.+Nucl+Med%22%5BJournal%5D)">Time-of-flight PET.</a> J. Nucl Med. 28 (3), 73-78 (1983).</li>
<li>Leo, W. R. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aLeo%2C+WR+%22Techniques+for+Nuclear+and+Particle+Physics+Experiments%22">Techniques for Nuclear and Particle Physics Experiments</a>. , second, Springer-Verlag. Germany. (1987).</li>
<li>Budinger, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Instrumentation+trends+in+nuclear+medicine%5BTitle%5D)+AND+%22Semin+Nucl+Med%22%5BJournal%5D)">Instrumentation trends in nuclear medicine.</a> Semin Nucl Med. 7 (4), 285-297 (1977).</li>
<li>Burnham, C., Bradshaw, J., Kaufmann, D., Chesler, D., Browner, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+Positron+tomography+employing+a+one+dimension+BGO+scintillation+camera%5BTitle%5D)+AND+%22IEEE+Trans.+Nucl.+Sci%22%5BJournal%5D)">A Positron tomography employing a one dimension BGO scintillation camera.</a> IEEE Trans. Nucl. Sci. 30 (1), 661-664 (1983).</li>
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</ol>

There are no competing financial interests.

该系统的一个重要方面是有很好的控制了空间和时间分辨率。 PET的空间分辨率由放射性衰变和湮灭，的物理特性，而且还通过一致登记的技术方面（步骤1.1和1.2）和由错误，如对象的运动的外部源的检查5中限定。因此，测量的确切位置将取决于飞行时间差（步骤2.4）。一种技术实现了良好的时间分辨率测量TOF 6的分布的半峰全宽（FWHM）。 每个PMT的特点是获?...

正电子发射断层摄影术是用于获得主体的内组织和器官的数字图像的非侵入性成像技术。各种非侵入性技术存在允许之一在患者的内部工作如计算机轴向断层（TAC）和磁共振成像（MRI）获得的图像和信息。既提供良好的空间分辨率，并另外用于在解剖和生理的研究应用。尽管相对的PET得到较少的空间分辨率，它提供了关于在感兴趣的区域中发生的代谢的更多信息。的PET被广泛用于获得功能和形态学的信息;其主要临床应用是在肿瘤学，神经病学和心脏病学领域中。此外，PET图像可以帮助医生更好地诊断， 例如，建立肿瘤治疗计划。 PET系统的基本工作原理是两坡的检测吨或伽玛射线从一个正电子 - 电子湮灭对到来，既飞行在朝向检测器，它通常由结合光电倍增管的闪烁体晶体的方向相反。闪烁体结晶转变的γ辐射转化为可见光，行进到的PMT经由一个光电过程的光信号转换为电脉冲。内的光电倍增管的电子设备称为倍增电极都存在，把它发送到一个读出系统之前这增加了电荷的幅度。创建这两个探测光子当一个正电子（电子带正电）由同位素流体，将其注入体内的血流中发射的，歼与体内的电子。读出系统测量重合两回到后端的光子相对于时间基准并且进一步它衬底既次，得到的差的到达时间。该系统使用这个时间差来计算空间中的位置WHERE辐射源发射两个光子，并且因此电子对湮灭发生的位置。 的PET系统中的某些功能，必须定义来优化图象的质量和增加的空间和时间分辨率。要考虑的一个特点是响应的线（LOR），定义为两个光子的湮灭过程之后行驶的距离。另一个特点要考虑的是飞行（TOF）的时间。图像质量还取决于外部特征，主要是身体器官和疗程1期间患者的动作。在PET系统中使用的同位素是称为贝塔+发射器。这些同位素具有短半衰期（秒数量级上）。他们生产的颗粒加速器（回旋加速器）时有稳定的元素轰炸质子或氘核引起核反应。这种反应变换稳定的元素融入到不稳定的同位素，如C-11，N-13，O-15，F-18等等2。 有两种类型的PET。 （1）常规:此使用飞行时间信息只以识别沿其湮没发生线，但它是无法确定两个光子的原点处。它需要额外的分析或迭代重建算法来估计这一点。 （2）TOF PET:利用TOF差来定位所发射的正电子的湮灭位置。时间分辨率被用在重建算法作为内核对于一个本地化概率函数3。 我们的主要目的是要证明的PET，其用于定位在空间中的辐射源的主要功能。这里提出的PET系统组的主要范围是提供一种基本的PET结构导向为学术公众，并解释，在一个简单的方法，它的主要性能。

<table><tbody><tr><td>Low threshold Discriminator</td><td>CAEN</td><td>N845</td><td></td></tr><tr><td>Logic Units</td><td>Lecroy</td><td>365AL</td><td></td></tr><tr><td>Time delay</td><td>CAEN</td><td>N108A</td><td></td></tr><tr><td>Oscilloscope</td><td>Tektronic</td><td>TDS3014C</td><td></td></tr><tr><td>Quad Scaler and preset counter</td><td>CAEN</td><td>N1145</td><td></td></tr><tr><td>TDC</td><td>Lecroy</td><td>2228</td><td></td></tr><tr><td>PMT&amp;rsquo;s</td><td>Hamamatsu</td><td>H5783p</td><td></td></tr><tr><td>Power Chasis</td><td>Lecroy</td><td>1403</td><td></td></tr><tr><td>GPIB Interface</td><td>Lecroy</td><td>8901A</td><td></td></tr><tr><td>NIM Power Supply</td><td>Lecroy</td><td>1002B</td><td></td></tr><tr><td>CAMAC Crate</td><td>Borer-co</td><td>1902A</td><td></td></tr><tr><td>Scintillator Crystals</td><td>Bicron</td><td>408</td><td>1 cm x 2 cm x 5 cm</td></tr><tr><td>Power Supply</td><td>Agilent</td><td>E3631</td><td></td></tr><tr><td>Na 22 Radioactive Source</td><td></td><td></td><td>activity 2&amp;nbsp;&amp;mu;Ci</td></tr><tr><td>Software LabView 7.1</td><td>National intruments</td><td></td><td></td></tr><tr><td>lemo cables connectors</td><td></td><td></td><td>2&amp;nbsp;nsec, 3&amp;nbsp;nsec and 8&amp;nbsp;nsec</td></tr><tr><td>isolator film</td><td></td><td></td><td></td></tr></tbody></table>

a basic positron emission tomography system constructed to locate a radioactive source in a bi-dimensional space

一个简单的正电子发射断层扫描（PET）样机已经建成全面检定其基本工作原理。在PET样机，通过偶合塑料闪烁体晶体光电倍增管或光电倍增管的其中被放置在相对的位置​​，以检测从一个放射源，其中被放置在PET的几何中心喷射2伽马射线创建设置。所述原型包括四个探测器在一个20厘米直径的圆几何放置，并在该中心放射源。通过从中间移动放射源厘米的系统中的一个是能够​​通过测量任何两个PMT的飞行之间的差异的时间，以检测的位移，并与该信息，系统可以计算在图形界面的虚拟位置。以这种方式，所述原型再现的PET系统的主要原则。它能够确定在2行的代以4cm间隔源的实际位置tection服用不到2分钟。

两个主要结果与该PET系统来实现。第一:虚拟放射源的视觉效果之间的一个有效的同步移动时的实际放射性样品。与此方案，用户可以控制的采集时间，重复在同一位置的数目，围绕采集数据的意思是，在其他的时间间隔的变化。第二:同时逻辑的结构简单的结构，以获得时间差的两个信号之间，转换这个时间差为距离来计算源的最终位置。 <p class="jove_content" fo:keep-togethe...

Watch this Scientific Journal Video about A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space at JoVE.com

A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space

We present a simple but well-constructed Positron Emission Tomography (PET) system and elucidate its basic working principles. The goal of this protocol is to guide the user in constructing and testing a simple PET system.

一个基本的正电子发射断层扫描系统构建以定位放射源的双维空间

A simple Positron Emission Tomography (PET) prototype has been constructed to fully characterize its basic working principles. The PET prototype was ...

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Engineering

8.5K 次观看.  Centro de Investigacion y de Estudios Avanzados del IPN (Cinvestav). We present a simple but well-constructed Positron Emission Tomography (PET) system and elucidate its basic working principles. The goal of this protocol is to guide the user in constructing and testing a simple PET system.

视频: A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space

PET and MRI Guided Irradiation of a Glioblastoma Rat Model Using a Micro-irradiator

For decades, small animal radiation research was mostly performed using fairly crude experimental setups applying simple single-beam techniques without the ability to target a specific or well-delineated tumor volume. The delivery of radiation was achieved using fixed radiation sources or linear accelerators producing megavoltage (MV) X-rays. These devices are unable to achieve sub-millimeter precision required for small animals. Furthermore, the high doses delivered to healthy surrounding tissue hamper response assessment. To increase the translation between small animal studies and humans, our goal was to mimic the treatment of human glioblastoma in a rat model. To enable a more accurate irradiation in a preclinical setting, recently, precision image-guided small animal radiation research platforms were developed. Similar to human planning systems, treatment planning on these micro-irradiators is based on computed tomography (CT). However, low soft-tissue contrast on CT makes it very challenging to localize targets in certain tissues, such as the brain. Therefore, incorporating magnetic resonance imaging (MRI), which has excellent soft-tissue contrast compared to CT, would enable a more precise delineation of the target for irradiation. In the last decade also biological imaging techniques, such as positron emission tomography (PET) gained interest for radiation therapy treatment guidance. PET enables the visualization of e.g., glucose consumption, amino-acid transport, or hypoxia, present in the tumor. Targeting those highly proliferative or radio-resistant parts of the tumor with a higher dose could give a survival benefit. This hypothesis led to the introduction of the biological tumor volume (BTV), besides the conventional gross target volume (GTV), clinical target volume (CTV), and planned target volume (PTV).
At the preclinical imaging lab of Ghent University, a micro-irradiator, a small animal PET, and a 7 T small animal MRI are available. The goal was to incorporate MRI-guided irradiation and PET-guided sub-volume boosting in a glioblastoma rat model.

In the past, small animal irradiation was usually performed without the ability to target a well-delineated tumor volume. The goal was to mimic the treatment of human glioblastoma in rats. Using a small animal irradiation platform, we performed MRI-guided 3D conformal irradiation with PET-based sub-volume boosting in a preclinical setting.

PET 与 MRI 引导下微器对大鼠胶质瘤模型的照射

For decades, small animal radiation research was mostly performed using fairly crude experimental setups applying simple single-beam techniques without ...

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癌症研究

Computed Tomography-guided Time-domain Diffuse Fluorescence Tomography in Small Animals for Localization of Cancer Biomarkers

Small animal fluorescence molecular imaging (FMI) can be a powerful tool for preclinical drug discovery and development studies1. However, light absorption by tissue chromophores (e.g., hemoglobin, water, lipids, melanin) typically limits optical signal propagation through thicknesses larger than a few millimeters2. Compared to other visible wavelengths, tissue absorption for red and near-infrared (near-IR) light absorption dramatically decreases and non-elastic scattering becomes the dominant light-tissue interaction mechanism. The relatively recent development of fluorescent agents that absorb and emit light in the near-IR range (600-1000 nm), has driven the development of imaging systems and light propagation models that can achieve whole body three-dimensional imaging in small animals3.
Despite great strides in this area, the ill-posed nature of diffuse fluorescence tomography remains a significant problem for the stability, contrast recovery and spatial resolution of image reconstruction techniques and the optimal approach to FMI in small animals has yet to be agreed on. The majority of research groups have invested in charge-coupled device (CCD)-based systems that provide abundant tissue-sampling but suboptimal sensitivity4-9, while our group and a few others10-13 have pursued systems based on very high sensitivity detectors, that at this time allow dense tissue sampling to be achieved only at the cost of low imaging throughput. Here we demonstrate the methodology for applying single-photon detection technology in a fluorescence tomography system to localize a cancerous brain lesion in a mouse model.
The fluorescence tomography (FT) system employed single photon counting using photomultiplier tubes (PMT) and information-rich time-domain light detection in a non-contact conformation11. This provides a simultaneous collection of transmitted excitation and emission light, and includes automatic fluorescence excitation exposure control14, laser referencing, and co-registration with a small animal computed tomography (microCT) system15. A nude mouse model was used for imaging. The animal was inoculated orthotopically with a human glioma cell line (U251) in the left cerebral hemisphere and imaged 2 weeks later. The tumor was made to fluoresce by injecting a fluorescent tracer, IRDye 800CW-EGF (LI-COR Biosciences, Lincoln, NE) targeted to epidermal growth factor receptor, a cell membrane protein known to be overexpressed in the U251 tumor line and many other cancers18. A second, untargeted fluorescent tracer, Alexa Fluor 647 (Life Technologies, Grand Island, NY) was also injected to account for non-receptor mediated effects on the uptake of the targeted tracers to provide a means of quantifying tracer binding and receptor availability/density27. A CT-guided, time-domain algorithm was used to reconstruct the location of both fluorescent tracers (i.e., the location of the tumor) in the mouse brain and their ability to localize the tumor was verified by contrast-enhanced magnetic resonance imaging.
Though demonstrated for fluorescence imaging in a glioma mouse model, the methodology presented in this video can be extended to different tumor models in various small animal models potentially up to the size of a rat17.

Diffuse fluorescence tomography offers a relatively low-cost and potentially high-throughout approach to preclinical in vivo tumor imaging. The methodology of optical data collection, calibration, and image reconstruction is presented for a computed tomography-guided non-contact time-domain system using fluorescent targeting of the tumor biomarker epidermal growth factor receptor in a mouse glioma model.

电脑断层导引的时域漫荧光体层摄影术在小动物的肿瘤生物标志物的本土化

Small animal fluorescence molecular imaging (FMI) can be a powerful tool for preclinical drug discovery and development studies1. However, light ...

医学

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

We present experimental protocols for visualizing various low-level gamma radiation sources in the ambient environment. Experiments were conducted by using a low-cost, high-sensitivity, omnidirectional, gamma-ray imaging Compton camera. In the laboratory, the position of a sub-MeV gamma radiation source such as 137Cs can easily be monitored via omnidirectional gamma-ray imaging obtained by the Compton camera. In contrast, a stationary, wall-mounted dose rate monitor cannot always successfully monitor such a source. Furthermore, we successfully demonstrated the possibility of visualizing the radioactivity movement in the environment, for example, the movement of a patient injected with 18F-fluorodeoxyglucose (18F-FDG) in a nuclear medicine facility. In the Fukushima field, we easily obtained omnidirectional gamma-ray images concerned with the distribution on the ground of low-level radioactive contamination by radioactive cesium released by the Fukushima Daiichi nuclear power plant accident in 2011. We demonstrate clear advantages of using our procedure with this camera to visualize gamma-ray sources. Our protocols can further be used to discover low-level gamma radiation sources, in place of stationary dose rate monitors and/or portable survey meters used conventionally.

We present experimental protocols for visualizing various low-level gamma radiation sources in the ambient environment using a low-cost, high-sensitivity, omnidirectional, gamma-ray imaging Compton camera.

使用低成本、高灵敏度、全向康普顿摄像机对低电平伽玛辐射源进行可视化

We present experimental protocols for visualizing various low-level gamma radiation sources in the ambient environment. Experiments were conducted by ...

环境科学

Positron Emission Tomography-based Dose Painting Radiation Therapy in a Glioblastoma Rat Model using the Small Animal Radiation Research Platform

A rat glioblastoma model to mimic chemo-radiation treatment of human glioblastoma in the clinic was previously established. Similar to the clinical treatment, computed tomography (CT) and magnetic resonance imaging (MRI) were combined during the treatment-planning process. Positron emission tomography (PET) imaging was subsequently added to implement sub-volume boosting using a micro-irradiation system. However, combining three imaging modalities (CT, MRI, and PET) using a micro-irradiation system proved to be labor-intensive because multimodal imaging, treatment planning, and dose delivery have to be completed sequentially in the preclinical setting. This also results in a workflow that is more prone to human error. Therefore, a user-friendly algorithm to further optimize preclinical multimodal imaging-based radiation treatment planning was implemented. This software tool was used to evaluate the accuracy and efficiency of dose painting radiation therapy with micro-irradiation by using an in silico study design. The new methodology for dose painting radiation therapy is superior to the previously described method in terms of accuracy, time efficiency, and intra- and inter-user variability. It is also an important step towards the implementation of inverse treatment planning on micro-irradiators, where forward planning is still commonly used, in contrast to clinical systems.

Here we present a protocol to perform preclinical positron emission tomography-based radiotherapy in a rat glioblastoma model using algorithms developed in-house to optimize the accuracy and efficiency.

使用小动物辐射研究平台在胶质母细胞瘤大鼠模型中基于正电子发射断层扫描的剂量绘画放射治疗

A rat glioblastoma model to mimic chemo-radiation treatment of human glioblastoma in the clinic was previously established. Similar to the clinical ...

<meta charset="utf8"></head><body>异种移植模型中 68个 Ga 标记纳米抗体的放射合成和 PET/CT 成像

Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of 68Ga-Labelled Nano Molecules

Small animal Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging techniques are crucial in preclinical cancer research, necessitating meticulous attention to radiotracer synthesis, quality assurance, and in vivo injection protocols. This study presents a comprehensive workflow tailored to enhance the robustness and reproducibility of small animal PET experiments. The synthesis process in the radiochemistry laboratory using 68Ga is detailed, highlighting stringent quality control and assurance protocols for each radiotracer production. Parameters such as concentration, molar activity, pH, and purity are rigorously monitored, aligning with standards applicable to human studies. This methodology introduces streamlined syringe preparation and a custom-designed 30G cannula for precise intravenous injections into mice. Monitoring of animal health during scanning, including temperature and heart rate, ensures their well-being throughout the procedure. Dosages for PET and SPECT scans are predetermined to balance data acquisition with minimizing radiation exposure to animals and researchers. Similarly, CT scans employ pre-programmed settings to limit radiation exposure, especially pertinent in long-term studies assessing treatment effects. By optimizing these steps, the workflow aims to standardize procedures, reduce variability, and enhance the quality of small animal PET/SPECT/CT imaging. This resource provides valuable insights for researchers seeking to improve the accuracy and reliability of preclinical investigations in molecular imaging, ultimately advancing the field.

<meta charset="utf8"></head><body>68个 Ga-labeled Nano 分子的放射性合成、质量控制和小动物正电子发射断层扫描成像

This paper describes the radiosynthesis, formulation, quality control of a new radiolabeled probe (i.e., 68Ga-labeled nanobody NM-02), and its use for small animal PET/CT imaging in a xenograft model.

68个 Ga-labeled Nano 分子的放射性合成、质量控制和小动物正电子发射断层扫描成像

Small animal Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging techniques are crucial in preclinical ...

Continuous Blood Sampling in Small Animal Positron Emission Tomography/Computed Tomography Enables the Measurement of the Arterial Input Function

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal blood time-activity concentration also known as arterial input function (AIF) is a key point, especially for the characterization of animal disease models and the introduction of newly developed radiotracers. The knowledge of radiotracer availability in the blood helps to interpret PET/CT-derived data of tissue activity. For this purpose, online blood sampling during the PET/CT imaging is advisable to measure the AIF. In contrast to manual blood sampling and image-derived approaches, continuous online blood sampling has several advantages. Besides the minimized blood loss, there is an improved resolution and a superior accuracy for the blood activity measurement. However, the major drawback of online blood sampling is the costly and time-consuming preparation to catheterize the femoral vessels of the animal. Here, we describe an easy and complete workflow for catheterization and continuous blood sampling during small animal PET/CT imaging and compared it to manual blood sampling and an image-derived approach. Using this highly-standardized workflow, the determination of the fluorodeoxyglucose ([18F]FDG) AIF is demonstrated. Further, this procedure can be applied to any radiotracer in combination with different animal models to create fundamental knowledge of tracer kinetic and model characteristics. This allows a more precise evaluation of the behavior of pharmaceuticals, both for diagnostic and therapeutic approaches in the preclinical research of oncological, neurodegenerative and myocardial diseases.

Here a protocol for continuous blood sampling during PET/CT imaging of rats to measure the arterial input function (AIF) is described. The catheterization, the calibration and setup of the system and the data analysis of the blood radioactivity are demonstrated. The generated data provide input parameters for subsequent bio-kinetic modeling.

小型动物正电子发射断层扫描/计算机断层扫描中的连续血液采样支持动脉输入函数的测量

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal ...

A Whole Body Dosimetry Protocol for Peptide-Receptor Radionuclide Therapy (PRRT): 2D Planar Image and Hybrid 2D+3D SPECT/CT Image Methods

Peptide-receptor-radionuclide-therapy (PPRT) is a targeted therapy that combines a short-range energy radionuclide with a substrate with high specificity for cancer cell receptors. After injection, the radiotracer is distributed throughout the entire body, with a higher uptake in tissues where targeted receptors are overexpressed. The use of beta/gamma radionuclide emitters enables therapy imaging (beta-emission) and post-therapy imaging (gamma-emission) to be performed at the same time. Post-treatment sequential images permit absorbed dose calculation based on local uptake and wash-in/wash-out kinetics. We implemented a hybrid method that combines information derived from both 2D and 3D images. Serial whole-body images and blood samples are acquired to estimate the absorbed dose to different organs at risk and to lesions disseminated throughout the body. A single 3D-SPECT/CT image, limited to the abdominal region, overcomes projection overlap on planar images of different structures such as the intestines and kidneys. The hybrid 2D+3D-SPECT/CT method combines the effective half-life information derived from 2D planar images with the local uptake distribution derived from 3D images. We implemented this methodology to estimate the absorbed dose for patients undergoing PRRT with 177Lu-PSMA-617. The methodology could, however, be implemented with other beta-gamma radiotracers. To date, 10 patients have been enrolled into the dosimetry study with 177Lu-PSMA-617 combined with drug protectors for kidneys and salivary glands (mannitol and glutamate tablets, respectively). The median ratio between kidney uptake at 24 h evaluated on planar images and 3D-SPECT/CT is 0.45 (range:0.32-1.23). The comparison between hybrid and full 3D approach has been tested on one patient, resulting in a 1.6% underestimation with respect to full 3D (2D: 0.829 mGy/MBq, hybrid: 0.315 mGy/MBq, 3D: 0.320 mGy/MBq). Treatment safety has been confirmed, with a mean absorbed dose of 0.73 mGy/MBq (range:0.26-1.07) for kidneys, 0.56 mGy/MBq (0.33-2.63) for the parotid glands and 0.63 mGy/MBq (0.23-1.20) for submandibular glands, values in accordance with previously published data.

A Whole Body Dosimetry Protocol for Peptide-Receptor Radionuclide Therapy PRRT: 2D Planar Image and Hybrid 2D+3D SPECT/CT Image Methods

This method estimates the absorbed dose of different structures for peptide-receptor-radionuclide-therapy (PRRT) with the possibility of avoiding organ overlap on 2D-projections. Serial whole-body planar images permit estimation of mean absorbed doses along the whole body, while the hybrid approach, combining planar images and 3D-SPECT/CT image, overcomes the limitations of structure overlapping.

肽受体放射性核素治疗（PRRT）全身多体型测定方案:2D平面图像和混合2D+3D SPECT/CT图像方法

Peptide-receptor-radionuclide-therapy (PPRT) is a targeted therapy that combines a short-range energy radionuclide with a substrate with high specificity ...

<meta charset="utf8"></head><body>PET-CT 扫描用于脑氧和葡萄糖代谢的多示踪研究

Multi-Tracer Studies of Brain Oxygen and Glucose Metabolism Using a Time-of-Flight Positron Emission Tomography-Computed Tomography Scanner

The authors have developed a paradigm using positron emission tomography (PET) with multiple radiopharmaceutical tracers that combines measurements of cerebral metabolic rate of glucose (CMRGlc), cerebral metabolic rate of oxygen (CMRO2), cerebral blood flow (CBF), and cerebral blood volume (CBV), culminating in estimates of brain aerobic glycolysis (AG). These in vivo estimates of oxidative and non-oxidative glucose metabolism are pertinent to the study of the human brain in health and disease. The latest positron emission tomography-computed tomography (PET-CT) scanners provide time-of-flight (TOF) imaging and critical improvements in spatial resolution and reduction of artifacts. This has led to significantly improved imaging with lower radiotracer doses.
Optimized methods for the latest PET-CT scanners involve administering a sequence of inhaled 15O-labeled carbon monoxide (CO) and oxygen (O2), intravenous 15O-labeled water (H2O), and 18F-deoxyglucose (FDG)-all within 2-h or 3-h scan sessions that yield high-resolution, quantitative measurements of CMRGlc, CMRO2, CBF, CBV, and AG. This methods paper describes practical aspects of scanning designed for quantifying brain metabolism with tracer kinetic models and arterial blood samples and provides examples of imaging measurements of human brain metabolism.

<meta charset="utf8"></head><body>使用飞行时间正电子发射断层扫描-计算机断层扫描扫描仪对脑氧和葡萄糖代谢进行多示踪研究

Quantitative measurements of oxygen and glucose metabolism by PET are established technologies, but details of practical protocols are sparsely described in the literature. This paper presents a practical protocol successfully implemented on a state-of-the-art positron emission tomography-computed tomography scanner.

使用飞行时间正电子发射断层扫描-计算机断层扫描扫描仪对脑氧和葡萄糖代谢进行多示踪研究

The authors have developed a paradigm using positron emission tomography (PET) with multiple radiopharmaceutical tracers that combines measurements of ...

一个基本的正电子发射断层扫描系统构建以定位放射源的双维空间

摘要

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PET 与 MRI 引导下微器对大鼠胶质瘤模型的照射

电脑断层导引的时域漫荧光体层摄影术在小动物的肿瘤生物标志物的本土化

使用低成本、高灵敏度、全向康普顿摄像机对低电平伽玛辐射源进行可视化

使用小动物辐射研究平台在胶质母细胞瘤大鼠模型中基于正电子发射断层扫描的剂量绘画放射治疗

⁶⁸个 Ga-labeled Nano 分子的放射性合成、质量控制和小动物正电子发射断层扫描成像

⁶⁸个 Ga-labeled Nano 分子的放射性合成、质量控制和小动物正电子发射断层扫描成像

⁶⁸个 Ga-labeled Nano 分子的放射性合成、质量控制和小动物正电子发射断层扫描成像

小型动物正电子发射断层扫描/计算机断层扫描中的连续血液采样支持动脉输入函数的测量

肽受体放射性核素治疗（PRRT）全身多体型测定方案:2D平面图像和混合2D+3D SPECT/CT图像方法

使用飞行时间正电子发射断层扫描-计算机断层扫描扫描仪对脑氧和葡萄糖代谢进行多示踪研究