First Demonstration of Multiplexed X-Ray Fluorescence Computed Tomography (XFCT) Imaging
First Demonstration of Multiplexed X-Ray Fluorescence Computed Tomography (XFCT) Imaging
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DOI：
10.1109/tmi.2012.2223709
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发表时间：
2013-02-01
影响因子：
10.6
通讯作者：
Xing, Lei
中科院分区：
文献类型：
--
作者：
Kuang, Yu;Pratx, Guillem;Xing, Lei
多个探针或生物标志物的同时成像代表了朝向高特异性分子成像的关键步骤。在这项工作中，我们建议利用元素的特定性质的X射线荧光（XRF）信号成像多个元素同时（复用）使用XRF计算机断层扫描（XFCT）。使用多色X射线源（150 kV，20 mA）产生的5 mm直径笔形束来刺激嵌入水模体内的2%（重量/体积）金（Au）、钆（Gd）和钡（Ba）的XRF光子发射。体模相对于第一代CT几何结构中的固定笔形射束平移和旋转。使用碲化镉探测器在每个位置收集X射线能谱18 s。然后使用光谱分离K壳层XRF峰并生成三种感兴趣元素的正弦图。采用迭代最大似然期望最大化算法重建三种元素的分布和浓度。研究了XFCT强度与感兴趣的元素的浓度之间的线性。我们发现，测量的XRF光谱显示出Au、Gd和Ba的尖峰特征。峰的窄的半峰全宽（FWHM）强烈支持XFCT用于Au、Gd和Ba的多重成像的潜力（FWHMAu，K α 1 = 0.619 keV，FWHMAu，K α 2 = 1.371 keV，FWHMGd，K α = 1.297 keV，FWHMGd，K β = 0.974 keV，FWHMBa，K α = 0.852 keV，和FWHMBa，K β = 0.594 keV）。在重建的XRF图像中，可清楚地识别水模体中Au、Gd和Ba的分布。结果表明，X射线荧光强度与元素浓度呈线性关系（R-Au（2）= 0.944，R-Gd（2）= 0.986，R-Ba（2）= 0.999），表明XFCT具有定量成像的能力。最后，一个透射CT图像得到的方法提供衰减校正和形态信息的潜力。总之，XFCT是一种很有前途的高原子序数探针多重成像方式。
Simultaneous imaging of multiple probes or biomarkers represents a critical step toward high specificity molecular imaging. In this work, we propose to utilize the element-specific nature of the X-ray fluorescence (XRF) signal for imaging multiple elements simultaneously (multiplexing) using XRF computed tomography (XFCT). A 5-mm-diameter pencil beam produced by a polychromatic X-ray source (150 kV, 20 mA) was used to stimulate emission of XRF photons from 2% (weight/volume) gold (Au), gadolinium (Gd), and barium (Ba) embedded within a water phantom. The phantom was translated and rotated relative to the stationary pencil beam in a first-generation CT geometry. The X-ray energy spectrum was collected for 18 s at each position using a cadmium telluride detector. The spectra were then used to isolate the K shell XRF peak and to generate sinograms for the three elements of interest. The distribution and concentration of the three elements were reconstructed with the iterative maximum likelihood expectation maximization algorithm. The linearity between the XFCT intensity and the concentrations of elements of interest was investigated. We found that measured XRF spectra showed sharp peaks characteristic of Au, Gd, and Ba. The narrow full-width at half-maximum (FWHM) of the peaks strongly supports the potential of XFCT for multiplexed imaging of Au, Gd, and Ba (FWHMAu,K alpha 1 = 0.619 keV, FWHMAu,K alpha 2 = 1.371 keV, FWHMGd,K alpha = 1.297 keV, FWHMGd,K beta = 0.974 keV, FWHMBa,K alpha = 0.852 keV, and FWHMBa,K beta = 0.594 keV). The distribution of Au, Gd, and Ba in the water phantom was clearly identifiable in the reconstructed XRF images. Our results showed linear relationships between the XRF intensity of each tested element and their concentrations (R-Au(2) = 0.944, R-Gd(2) = 0.986, and R-Ba(2) = 0.999), suggesting that XFCT is capable of quantitative imaging. Finally, a transmission CT image was obtained to show the potential of the approach for providing attenuation correction and morphological information. In conclusion, XFCT is a promising modality for multiplexed imaging of high atomic number probes.