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Tomographic challenges in the industry

Jan Sijbers, University of Antwerp

Monday, 13 October 2014 14:10

Tomography is an important tool in many industrial applications. An obvious application is the visualization of the internal structure of objects. However, it is used as well for monitoring or optimizing processes or inspection of components. In this talk, we will show some examples of X-ray tomography in diamond processing, food processing, 3D printing industry,  and the medical sector. Within these examples, several acquisition geometries are used, ranging from conventional CT to a conveyor geometry; both challenges and possible solutions are addressed.

 


Application of X-ray microtomography in food research -challenges of today and tomorrow

Gerard Van Dalen, Unilever

Monday, 13 October 2014 15:00

Knowledge of the nano-, micro and macrostructure of food products and its intricate relation to product properties is necessary to develop new and better products. Consumers need high quality food products with a superior taste, texture, freshness and shelf life that are ready-to-eat or quick and easy to prepare. These food products contain complex structural features such as pores, droplets, crystals, interfaces and networks.  X-ray computed micro-tomography (µCT) is an essential part of a broad range of complementary imaging techniques used to visualise structure elements during processing and storage. The applicability of µCT can be extended when issues regarding contrast, resolution, field of view, speed and sample disturbance can be improved.

 


Opportunities and Challenges of Iterative Reconstruction in Medical X-Ray Computed Tomography

Thomas Koehler, Philips Medical

Monday, 13 October 2014 15:30

X-ray Computed Tomography (CT) is a versatile and widely used medical imaging modality that generates three-dimensional images of the linear x-ray attenuation coefficient. Current CT scanners suffer from a poor contrast-to-noise ratio (CNR) in the soft tissue regime, which demands the additional use of contrast agent and/or rather high x-ray dose for soft-tissue protocols. Strategies to mitigate this issue will be reviewed; in particular the use of photon counting detectors and iterative reconstruction.

 


Direct conversion CdTe-CMOS detectors for medical and industrial X-ray imaging

Andeas Hauptmann, Ajat

Monday, 13 October 2014 16:15

We are surveying various applications and advantages of CdTe-CMOS X-ray detectors. The high attenuation coefficient of cadmium telluride semiconductors and the efficiency of CMOS circuits provide high speed and low noise imaging. The radiation energy can be directly converted to signal charge, which leads to high detective quantum efficiency (DQE). A high frame rate of 300 frames per second and small charge integration pixel size of 100$\mu$m provide sharp images. We will present the realization and design of systems for various medical and industrial applications.

 


CBCT for Gamma Knife radiosurgery

Jonas Adler, Elekta

Monday, 13 October 2014 16:45

In the latest development of the Gamma Knife a CBCT is mounted to the system. The primary purpose of the CBCT system is positioning of the patient at the time of treatment by co-registering the CBCT images with earlier planning MR or CT images, thereby determining the iso-center coordinates of the radiation field.
 
Elekta is interested in expanding the abilities of the CBCT system. For example, better Hounsfield correctness would allow precise dose calculation without the need of prior CT images and better soft tissue contrast would increase the probability that the practitioner identify tumors (movements). As always, there is also an interest in very low dose protocols to minimize the risk of inducing second order cancer.

 


Computed laminography with a priori information

Christian Schorr, Fraunhofer

Monday, 13 October 2014 17:15

Computed tomography (CT) is a very powerful tool in medicine and non-destructive testing but is unsuitable for planar objects like fiber reinforced plastics sheets or printed circuit boards due to their strongly varying penetration lengths and spatial restrictions during the scan. A solution can be found in the use of computed laminography (CL), a technique where the object is irradiated by an oblique angle, thereby circumventing the problems arising in CT. Due to the resulting limitedangular coverage, the reconstruction is computed using flexible iterative methods like SART, which also allow for the use of a priori information about the object's geometry. This approach can severely reduce typical laminographic and region-of-interest artefacts while increasing contrast and defect detectability. Examples of a priori optimized computed laminography both from simulated and measured data will be shown.

 


Real Time Imaging of Pore Scale Flow

Steffen Berg, Shell

Tuesday, 14 October 2014 09:00

The recovery of Oil and gas involves the flow of multiple immiscible phases in porous and permeable rock. The details of this complicated multiphase flow on the pore scale is not fully understood. To a large extent that is because so far it was not possible to directly image the flow at its natural length and time scales. Recent advances in fast X-ray computed micro-tomography have made it possible to image pore scale displacement in multiphase flow in porous rock at time intervals of 1-40 s. However, there is an even faster dynamics on the time scale well below 1 s which is currently inaccessible with conventional tomography reconstruction techniques. More modern reconstruction techniques which employ prior information and allow to add constraints can likely improve the imaging speed by a factor of 10 and potentially also offer reconstruction and segmentation in one step.

 


Challenges in Industrial Computed Tomography

Wouter Danckaert, Inside Matters

Tuesday, 14 October 2014 09:30

CT has the potential to become a high added value digital inspection tool for industrial applications, as it allows to obtain detailed information about products, prototypes and materials in a non-destructive way. However, for many real world applications the technical constraints regarding resolution, image contrast, sample handling and throughput time hinder its wide spread application in the field. In our presentation, we will illustrate these challenges and limitations by examples from our service activities.

 


Reconstruction and segmentation of piecewise constant functions from tomography data

Esther Klann, RICAM

Tuesday, 14 October 2014 10:45

We consider the  reconstruction of piecewise constant functions  from tomography data. We present two approaches: the first provides simultaneously a segmentation with the reconstruction by detecting boundaries of objects directly from the given data. This approach uses shape sensitivity and is realized via level-sets. We apply this method to (generated) data from a torso phantom. The second approach presents a weigthed wavelet method that allows to focus the reconstruction quality on specific regions. We apply this method to (generated) region of interest data.

 


Synchrotron microCT: a powerful tool for material characterization for both academic and industrial purposes.

Elodie Boller, European Synchrotron Radiation Facility (ESRF)

Tuesday, 14 October 11:45

Since more than a decade, micro-computing tomography (micro-CT) instruments were developed at the European Synchrotron Radiation Facility (ESRF in France). Micro-CT is now the main imaging technique of the 150 m-long beamline ID19. Within the context of the ESRF general upgrade (Phase 1: 2008-2015), ID19 is benefiting from a consequent refurbishment: both medium and high resolution are optimized, trying to use as best the specificities of a 6 GeV 3rd generation synchrotron, like coherence and high energies, comparing to other synchrotron source and laboratory instruments. New samples stages have been designed to accept very large objects (up to half-meter range). A transfocator (combination of Be compound refractive lenses) has been implemented in the optics hutch to gain flux at high resolution and another one has just been finalized to enlarge the beam in the vertical direction (limited to 15mm today, beam of 80x80mm2 is expected in 2015).

Micro-CT is successfully applied to characterise various specimens and numerous experiments, academic and industrial, are done weekly. The main applications are originating from materials sciences, palaeontology and biomedical research. Synchrotron radiation provides high photon flux density, especially in the so-called pink beam (polychromatic) mode, using single-harmonic undulators (19 and recently 26 keV) or filtered white beam. This possibility leads to develop in situ experiments to add a fourth dimension to studies (time, temperature, …). Samples can be investigated in situ, employing different sample environments like tensile stress, compression, fatigue devices, low or high temperature, hygrometry control, and more recently high temperature under controlled atmosphere.