The computed tomography imaging of a local region inside a sample with a size larger than the field of view is particularly important for synchrotron X-ray imaging.In this letter,an improved algorithm is proposed to reconstruct the local structure inside a sample using almost completely local data.The algorithm significantly reduces the X-ray radiation dose and improves computational efficiency.Simulation results show that the new algorithm works well and has a higher reconstruction precision than previous methods,as confirmed by experimental results carried out at the Shanghai Synchrotron Radiation Facility.
The micro-CT imaging of vasculature is a powerful tool for evaluation of angiogenesis,a prominent characteristic of hepatic fibrosis.The segment or bifurcation density,which is usually adopted to evaluate the degree of hepatic fibrosis,does not always work and may lead to incorrect assessment,especially when the threedimensional vasculature obtained is imperfect in sample preparation or image collection.In this paper,we propose a new parameter to solve this problem.The experimental results demonstrate that the method is robust and reliable,and is practical for angiogenesis evaluation,despite of image data imperfections.This quantitative analysis method can be extended to investigate other kinds of diseases in which vasculature change is a key indicator.
We present a fast synchrotron X-ray tomography study of the packing structures of rods with different aspect ratios. Utilizing the high flux of the X-rays generated from the third-generation synchrotron source, we can complete a high- resolution tomography scan within a short period of time, after which the three-dimensional （3D） packing structure can be obtained for the subsequent structural analysis. The image phase-retrieval procedure has been implemented to enhance the image contrast. We systematically investigated the effects of particle shape and aspect ratio on the structural properties including packing density and contact number. It turns out that large aspect ratio rod packings will have wider distributions of free volume fraction and larger mean contact numbers.
