Real-time, high speed, high resolution, 4D CT at laboratory setups

Performing CT experiments on samples that are morphologically changing shape as a function of time is not straightforward, especially if the modifications happen in a short period of time and the altering structures are relatively small. These kind of experiments are challenging as large amounts of data are generated in a short amount of time and it is difficult to target the right time period where the change of interest can be observed. Additionally, hardware limitations in terms of acquisition speed and sufficient X-ray flux are problematic, especially at laboratory setups. Here we present some CT-results where a time resolution of 1sec is achieved over a period of 2 min using a combination of hard- and software that is specifically designed for high speed, high resolution, 4D CT

Evaluation of phase correction algorithms outside the validity boundaries

In high-resolution X-ray Computed Tomography, the phase shift and refraction of X-rays can under certain circumstances become visible in the projection images, being superimposed on the attenuation images. As such, it can also become visible in the reconstructed volume. This can be beneficiary for the visualization, yet it is often considered an imaging artefact which hinders proper 3D analysis. Under normal experimental conditions, it is mathematically not possible to retrieve the phase information or the attenuation information correctly without multiple acquisitions. However, several methods exist to perform phase retrieval or phase correction, which use assumptions on the object or the imaging setup. In this presentation, the effect of a violation of these assumptions is discussed

Realistic CT image simulation tools for laboratory based X-ray CT at UGCT

In laboratory based X-ray Computed Tomography (CT), the grey values in the resulting CT image depend on several scanning conditions such as the emitted spectrum, the response characteristics of the detector and beam filtration. Furthermore, due to beam hardening also the morphology and composition of the sample itself will have a significant influence. Therefore, to optimise scanning conditions simulations which incorporate all factors determining the imaging process are required. In this paper, two programs developed at the Centre for X-ray Tomography of the Ghent University (UGCT) are presented which allow a complete and realistic simulation of the obtained CT image

A LabVIEW® based generic CT scanner control software platform

UGCT, the Centre for X-ray tomography at Ghent University (Belgium) does research on X-ray tomography and its applications. This includes the development and construction of state-of-the-art CT scanners for scientific research. Because these scanners are built for very different purposes they differ considerably in their physical implementations. However, they all share common principle functionality. In this context a generic software platform was developed using LabVIEW (R) in order to provide the same interface and functionality on all scanners. This article describes the concept and features of this software, and its potential for tomography in a research setting. The core concept is to rigorously separate the abstract operation of a CT scanner from its actual physical configuration. This separation is achieved by implementing a sender-listener architecture. The advantages are that the resulting software platform is generic, scalable, highly efficient, easy to develop and to extend, and that it can be deployed on future scanners with minimal effort

Modelling of X-ray tube spot size and heel effect in Arion

X-rays produced in X-ray tubes originate from a focal spot on the target material. This spot is not infinitely small, but has a finite size. This finite size of the spot will affect the radiographic projections taken during X-ray Compted tomography. In order to simulate correct radiographic projections, this finite spot size needs to be taken into account during the simulations. This can be done by modelling a two dimensional profile of the spot and use this model to convolve the simulated radiographic projections simulated with an infinitely small spot size. A second effect, the heel effect that originates in directional X-ray tubes will also have an influence on the final projections. This effect can also be modelled and this model can be used to correct the simulated projections for this effect