Reconstruction Algorithm of Fan-Beam Helical X-Ray Computer Tomography Based on Grating Imaging

X-ray microfocus computer tomography (μ-CT) is a non-destructive experimental technique that reveals the 3D internal microstructure of the sample under study. The experimental set-up consists of an X-ray source, an X-ray detector, and set in between is a sample that is placed on a rotation stage. With this set-up multiple X-ray projection images can be obtained from the sample at different angles. In between the acquisition of two successive images, the sample is rotated over a small angle, typically between 0.2° and 1°. This set of projection images is then used as input for the reconstruction algorithm, which calculates a reconstruction of the internal microstructure of the sample with (sub-) micrometer sensitivity.

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Nondestructive Inspection of Thin, Low-Z Samples using Multiplexed Compton Scatter Tomography

MRS Proceedings ◽

10.1557/proc-503-297 ◽

1997 ◽

Vol 503 ◽

Cited By ~ 1

Author(s):

B. L. Evans ◽

J. B. Martin ◽

L. W. Burggraf

Keyword(s):

Signal To Noise Ratio ◽

Reconstruction Algorithm ◽

Filtered Backprojection ◽

Line Broadening ◽

Compton Scatter ◽

X Ray ◽

Tomography System ◽

Transmission Computed Tomography ◽

High Purity Germanium ◽

Scattered Energy

ABSTRACTThe viability of a Compton scattering tomography system for nondestructively inspecting thin, low Z samples for corrosion is examined. This technique differs from conventional x-ray backscatter NDI because it does not rely on narrow collimation of source and detectors to examine small volumes in the sample. Instead, photons of a single energy are backscattered from the sample and their scattered energy spectra are measured at multiple detector locations, and these spectra are then used to reconstruct an image of the object. This multiplexed Compton scatter tomography technique interrogates multiple volume elements simultaneously. Thin samples less than 1 cm thick and made of low Z materials are best imaged with gamma rays at or below 100 keV energy. At this energy, Compton line broadening becomes an important resolution limitation. An analytical model has been developed to simulate the signals collected in a demonstration system consisting of an array of planar high-purity germanium detectors. A technique for deconvolving the effects of Compton broadening and detector energy resolution from signals with additive noise is also presented. A filtered backprojection image reconstruction algorithm with similarities to that used in conventional transmission computed tomography is developed. A simulation of a 360–degree inspection gives distortion-free results. In a simulation of a single-sided inspection, a 5 mm × 5 mm corrosion flaw with 50% density is readily identified in 1-cm thick aluminum phantom when the signal to noise ratio in the data exceeds 28.

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The value of x-ray computer tomography and orbit ultrasound in the diagnosis of Wegener's granulomatosis

POINT OF VIEW EAST – WEST ◽

10.25276/2410-1257-2020-1-52-53 ◽

2020 ◽

pp. 52-53

Author(s):

R.F. Gainutdinova ◽

Keyword(s):

Computer Tomography ◽

Wegener’S Granulomatosis ◽

Wegener's Granulomatosis ◽

X Ray

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Comparison of Laboratory Compaction Methods using X-ray Computer Tomography

Road Materials and Pavement Design ◽

10.3166/rmpd.8.139-164 ◽

2007 ◽

Vol 8 (2) ◽

pp. 139-164 ◽

Cited By ~ 2

Author(s):

Manfred N Partl ◽

Alexander Flisch ◽

M Jönsson

Keyword(s):

Computer Tomography ◽

X Ray

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Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

Polymers ◽

10.3390/polym13081271 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1271

Author(s):

Andreas Koenig ◽

Leonie Schmohl ◽

Johannes Scheffler ◽

Florian Fuchs ◽

Michaela Schulz-Siegmund ◽

...

Keyword(s):

Flexural Strength ◽

Computer Tomography ◽

Mechanical Performance ◽

Dental Materials ◽

Three Dimensional ◽

X Rays ◽

Scanning Calorimetry ◽

X Ray ◽

Multiple Measurements ◽

High Doses

The aim of the study was to investigate the effect of X-rays used in micro X-ray computer tomography (µXCT) on the mechanical performance and microstructure of a variety of dental materials. Standardised bending beams (2 × 2 × 25 mm3) were forwarded to irradiation with an industrial tomograph. Using three-dimensional datasets, the porosity of the materials was quantified and flexural strength was investigated prior to and after irradiation. The thermal properties of irradiated and unirradiated materials were analysed and compared by means of differential scanning calorimetry (DSC). Single µXCT measurements led to a significant decrease in flexural strength of polycarbonate with acrylnitril-butadien-styrol (PC-ABS). No significant influence in flexural strength was identified for resin-based composites (RBCs), poly(methyl methacrylate) (PMMA), and zinc phosphate cement (HAR) after a single irradiation by measurement. However, DSC results suggest that changes in the microstructure of PMMA are possible with increasing radiation doses (multiple measurements, longer measurements, higher output power from the X-ray tube). In summary, it must be assumed that X-ray radiation during µXCT measurement at high doses can lead to changes in the structure and properties of certain polymers.

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