X-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects using 110 kVp x-rays
X-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects using 110 kVp x-rays
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DOI：
10.1088/0031-9155/55/3/007
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发表时间：
2010-02-01
影响因子：
3.5
通讯作者：
Cho, Sang Hyun
中科院分区：
文献类型：
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作者：
Cheong, Seong-Kyun;Jones, Bernard L.;Cho, Sang Hyun
传统的X射线荧光计算机断层扫描（XFCT）技术需要单色同步加速器X射线来同时确定样品中各种元素（例如金属）的空间分布和浓度。然而，基于同步加速器的XFCT技术似乎不适合在典型的实验室设置下的体内成像。据我们所知，在这项研究中，我们首次证明了使用多色诊断能量范围X射线对含有相对低浓度金纳米颗粒（GNPs）的动物大小的小物体进行XFCT成像的可能性。具体地，我们创建了由聚甲基丙烯酸甲酯塑料制成的体模，其包含分别填充有1和2wt%GNP的盐水溶液的两个圆柱形柱，模仿小动物内的肿瘤/器官。然后，在对X射线束进行适当过滤并对检测器进行准直后，在笔形束几何结构下使用微焦点110 kVp X射线束和碲化镉（CdTe）X射线检测器对体模进行XFCT扫描。重建的图像清楚地确定了两个GNP填充柱的位置，其具有与金浓度水平成正比的不同对比度水平。另一方面，XFCT的当前双光束实现对于GNP的常规体内成像任务尚不实用，特别是在扫描时间方面。然而，通过使用多个探测器和有限数量的投影，它仍然可以用于对小于当前体模尺寸的一些对象进行成像。目前的研究提出了几个修改策略，目前的XFCT设置，如采用准单色锥/扇形X射线束和XFCT特定的空间滤波器或针孔检测器准直器，以建立一个台式XFCT系统的最终可行性为基础的GNP临床前分子成像应用。
A conventional x-ray fluorescence computed tomography (XFCT) technique requires monochromatic synchrotron x-rays to simultaneously determine the spatial distribution and concentration of various elements such as metals in a sample. However, the synchrotron-based XFCT technique appears to be unsuitable for in vivo imaging under a typical laboratory setting. In this study we demonstrated, for the first time to our knowledge, the possibility of performing XFCT imaging of a small animal-sized object containing gold nanoparticles (GNPs) at relatively low concentrations using polychromatic diagnostic energy range x-rays. Specifically, we created a phantom made of polymethyl methacrylate plastic containing two cylindrical columns filled with saline solution at 1 and 2 wt% GNPs, respectively, mimicking tumors/organs within a small animal. XFCT scanning of the phantom was then performed using microfocus 110 kVp x-ray beam and cadmium telluride (CdTe) x-ray detector under a pencil beam geometry after proper filtering of the x-ray beam and collimation of the detector. The reconstructed images clearly identified the locations of the two GNP-filled columns with different contrast levels directly proportional to gold concentration levels. On the other hand, the current pencil-beam implementation of XFCT is not yet practical for routine in vivo imaging tasks with GNPs, especially in terms of scanning time. Nevertheless, with the use of multiple detectors and a limited number of projections, it may still be used to image some objects smaller than the current phantom size. The current investigation suggests several modification strategies of the current XFCT setup, such as the adoption of the quasi-monochromatic cone/fan x-ray beam and XFCT-specific spatial filters or pinhole detector collimators, in order to establish the ultimate feasibility of a bench-top XFCT system for GNP-based preclinical molecular imaging applications.