Gasilov Sergei, Mittone Alberto, Brun Emmanuel, Bravin Alberto, Grandl Susanne, Coan Paola
Department of Physics, Ludwig Maximilians University, Garching 85748, Germany.
Biomed Opt Express. 2013 Aug 2;4(9):1512-8. doi: 10.1364/BOE.4.001512. eCollection 2013.
One of the most promising applications of the X-ray phase-contrast imaging is the three dimensional tomographic reconstruction of the index of refraction. However, results reported so far are limited to relatively small samples. We present here the tomographic reconstruction of the index of refraction distribution of a large biomedical sample (> 10 cm diameter). A quantitative study comparing the absorption and phase contrast (analyzer-based) tomography images shows that the distribution of the index of refraction obtained with the phase contrast method provides a more accurate depiction (3-10 times larger signal to noise ratio values) of the sample internal structure. Thanks to the higher sensitivity of this method, the improved precision was obtained using an incoming photon fluence on the sample several times smaller than in the case of absorption imaging.
X射线相衬成像最有前景的应用之一是折射率的三维断层重建。然而，目前报道的结果仅限于相对较小的样本。我们在此展示了一个大型生物医学样本（直径>10厘米）折射率分布的断层重建。一项比较吸收断层成像和相衬（基于分析器）断层成像图像的定量研究表明，用相衬方法获得的折射率分布能更准确地描绘样本内部结构（信噪比数值大3至10倍）。由于该方法具有更高的灵敏度，在样本上使用的入射光子注量比吸收成像时小几倍的情况下仍能获得更高的精度。
