Potential use of microbubbles (MBs) as contrast material in x-ray dark field (DF) imaging: How does the DF signal change with the characteristic parameters of the MBs?
Potential use of microbubbles (MBs) as contrast material in x-ray dark field (DF) imaging: How does the DF signal change with the characteristic parameters of the MBs?
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DOI：
10.1117/12.2216322
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
Ran Zhang;Bin Qin;Yongshuai Ge;B. Whiting;Ke Li;F. Villanueva;Guang-Hong Chen
中科院分区：
文献类型：
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作者：
Ran Zhang;Bin Qin;Yongshuai Ge;B. Whiting;Ke Li;F. Villanueva;Guang-Hong Chen
基于光栅的X射线差分相衬(DPC)采集方法最令人兴奋的方面之一是同时产生所谓的暗场(DF)信号，以及经典的吸收信号和新的DPC信号。DF信号与图像对象中小角度散射体的局部分布相关联，而吸收信号和DPC信号通常用于表征图像对象的相对均匀的结构。在X射线成像中，除了内源性图像对比度外，还经常使用外源性对比剂来局部增强图像信号。本文提出了一种潜在的对比剂：微气泡(MBS)。MBS已经被开发用于临床超声成像，最近的实验研究表明MBS也可以增强DF信号，尽管目前尚不清楚MBS的物理特性如何定量地影响DF信号。本文系统地研究了Df信号与MBS的尺寸、浓度、壳层厚度、尺寸均匀性以及是否附着金纳米颗粒之间的定量关系。实验结果表明，增加MB尺寸(约4微米)可以为我们的DPC成像系统产生更强的DF信号；此外，适度增加外壳厚度和在外壳表面使用金纳米颗粒也会导致DF信号进一步增强。这些发现可能为使用MBS作为x射线DF成像的造影剂提供关键信息。
One of the most exciting aspects of the grating based x-ray differential phase contrast (DPC) acquisition method is the concurrent generation of the so-called dark field (DF) signal, along with the classical absorption signal and the novel DPC signal. The DF signal is associated with local distribution of small angle scatterers in an image object, while the absorption signal and DPC signal are often used to characterize the relatively uniform structure of the image object. Besides the endogenous image contrast, exogenous contrast media are often used in x-ray imaging to locally enhance the image signal. This paper proposes a potential contrast medium for DF signal enhancement: microbubbles (MBs). MBs have already been developed for clinical use in ultrasound imaging, and recent experimental studies have shown that MBs may also enhance the DF signal, although it remained unclear how the physical characteristics of the MBs quantitatively impact the DF signal. In this paper, a systematic study was performed to investigate the quantitative relationships between the DF signal and the following properties of MBs: size, concentration, shell thickness, size uniformity, and whether gold nanoparticles were attached. The experimental results demonstrated that, an increased MB size (about 4 microns) may generate a stronger DF signal for our DPC imaging system; additionally, a moderately increased shell thickness and the use of gold nanoparticles on the shell surface also resulted in further enhancement of the DF signal. These findings may provide critical information needed for using MBs as the contrast agent of x-ray DF imaging.