Priors for X-ray in-line phase tomography of heterogeneous objects
Priors for X-ray in-line phase tomography of heterogeneous objects
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DOI：
10.1098/rsta.2013.0129
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发表时间：
2014-03-06
期刊：
影响因子：
5
通讯作者：
Peyrin, Francoise
中科院分区：
文献类型：
--
作者：
Langer, Max;Cloetens, Peter;Peyrin, Francoise
提出了一种新的先验方法，用于从X射线菲涅耳衍射图样中恢复相位。菲涅耳衍射图案是通过让高度相干的X射线束在与物体相互作用后在自由空间中传播来实现的。在此之前，已经使用了均匀或多材料对象假设。均匀物体假设的优点是可以在Radon域中引入先验。另一方面，异构对象先验必须应用于对象域。在这里，我们让衰减和折射率之间的关系作为测量的衰减指数的函数而变化。使用在射束线ID19（ESRF，Grenoble，France）处采集的体模图像（通过线性插值计算先验）和从大鼠截骨模型获得的愈合骨图像对该方法进行评价。结果表明，不同矿化程度的骨中衰减和折射率之间的比率遵循幂律。使用混合方法进行重建，但与其他更先进的模型兼容。我们实现了更精确的重建比以前在文献中报道。我们相信，所提出的方法将发现在生物医学成像问题中的对象是强烈的异质性，如骨愈合和生物材料工程的应用。
We present a new prior for phase retrieval from X-ray Fresnel diffraction patterns. Fresnel diffraction patterns are achieved by letting a highly coherent X-ray beam propagate in free space after interaction with an object. Previously, either homogeneous or multi-material object assumptions have been used. The advantage of the homogeneous object assumption is that the prior can be introduced in the Radon domain. Heterogeneous object priors, on the other hand, have to be applied in the object domain. Here, we let the relationship between attenuation and refractive index vary as a function of the measured attenuation index. The method is evaluated using images acquired at beamline ID19 (ESRF, Grenoble, France) of a phantom where the prior is calculated by linear interpolation and of a healing bone obtained from a rat osteotomy model. It is shown that the ratio between attenuation and refractive index in bone for different levels of mineralization follows a power law. Reconstruction was performed using the mixed approach but is compatible with other, more advanced models. We achieve more precise reconstructions than previously reported in literature. We believe that the proposed method will find application in biomedical imaging problems where the object is strongly heterogeneous, such as bone healing and biomaterials engineering.