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Purpose – The purpose of this paper is to develop a realistic computational model of carbon fibre reinforced polymer (CFRP) structures dedicated for in-silico investigations of the use of X-ray-based imaging techniques as non-destructive testing (NDT) of CFRP parts. Design/methodology/approach – CFRPs contain layers of carbon-fibres bundles within resin. Bundles’ orientation in the different layers is arranged with respect to each other at a well-defined primary direction. In the model, the bundle was simulated as a circular cylinder. The resulted model is a stack of layers of unidirectional bundles having orientation of 0°/90°/45°/−45°. Two CFRP structures were modelled: a flat CFRP part and a real shaped CFRP clip. A porous layer and non-carbon fibres were inserted within each model, respectively. X-ray projection images were generated with a dedicated simulation programme. Three setups were investigated: radiography, tomosynthesis and cone-beam CT (CBCT). Findings – Results showed that porosity and non-carbon fibres were visible with all X-ray-based techniques. Tomosynthesis and CBCT, however, provide higher quality image of defects. Practical implications – The CFRP computational model is a valuable tool in design, testing and optimization phase of X-ray-based imaging techniques for use in NDT of composite materials. Simulated images are generated within a short time; thus results from virtual optimization and testing are obtained very fast and at low cost. Originality/value – An innovative computational model of CFRP structures, dedicated for X-ray imaging simulations, has been developed. The model is characterized by simplicity in its creation and realistic visual appearance of the produced X-ray images.

The aim of this study is to investigate the impact on image quality of using monochromatic beams for lower dose breast tomosynthesis (BT). For this purpose, modeling and simulation of BT and mammography imaging processes have been performed using two x-ray beams: one at 28 kVp and a monochromatic one at 19 keV at different entrance surface air kerma ranging between 0.16 and 5.5 mGy. Two 4 cm thick computational breast models, in a compressed state, were used: one simple homogeneous and one heterogeneous based on CT breast images, with compositions of 50% glandular-50% adipose and 40% glandular-60% adipose tissues by weight, respectively. Modeled lesions, representing masses and calcifications, were inserted within these breast phantoms. X-ray transport in the breast models was simulated with previously developed and validated Monte Carlo application. Results showed that, for the same incident photon fluence, the use of the monochromatic beam in BT resulted in higher image quality compared to the one using polychromatic acquisition, especially in terms of contrast. For the homogenous phantom, the improvement ranged between 15% and 22% for calcifications and masses, respectively, while for the heterogeneous one this improvement was in the order of 33% for the masses and 17% for the calcifications. For different exposures, comparable image quality in terms of signal-difference-to-noise ratio and higher contrast for all features was obtained when using a monochromatic 19 keV beam at a lower mean glandular dose, compared to the polychromatic one. Monochromatic images also provide better detail and, in combination with BT, can lead to substantial improvement in visualization of features, and particularly better edge detection of low-contrast masses.

The major objective is to adopt, apply and test developed in-house algorithms for volumetric breast reconstructions from projection images, obtained in in-line phase-contrast mode. Four angular sets, each consisting of 17 projection images obtained from four physical phantoms, were acquired at beamline ID17, European Synchroton Radiation Facility, Grenoble, France. The tomosynthesis arc was ±32°. The physical phantoms differed in complexity of texture and introduced features of interest. Three of the used phantoms were in-house developed, and made of epoxy resin, polymethyl-methacrylate and paraffin wax, while the fourth phantom was the CIRS BR3D. The projection images had a pixel size of 47 μm × 47 μm. Tomosynthesis images were reconstructed with standard shift-and-add (SAA) and filtered backprojection (FBP) algorithms. It was found that the edge enhancement observed in planar x-ray images is preserved in tomosynthesis images from both phantoms with homogeneous and highly heterogeneous backgrounds. In case of BR3D, it was found that features not visible in the planar case were well outlined in the tomosynthesis slices. In addition, the edge enhancement index calculated for features of interest was found to be much higher in tomosynthesis images reconstructed with FBP than in planar images and tomosynthesis images reconstructed with SAA. The comparison between images reconstructed by the two reconstruction algorithms shows an advantage for the FBP method in terms of better edge enhancement. Phase-contrast breast tomosynthesis realized in in-line mode benefits the detection of suspicious areas in mammography images by adding the edge enhancement effect to the reconstructed slices.

Closed intramedullary nailing is a common technique for treatment of femur and tibia fractures. The most challenging step in this procedure is the precise placement of the lateral screws that stabilize the fragmented bone. The present work concerns the development and the evaluation of a method to accurately identify in the 3D space the axes of the nail hole canals. A limited number of projection images are acquired around the leg with the help of a C-arm. On two of them, the locking hole entries are interactively selected and a rough localization of the hole axes is performed. Perpendicularly to one of them, cone-beam computed tomography (CBCT) reconstructions are produced. The accurate identification and localization of the hole axes are done by an identification of the centers of the nail holes on the tomograms and a further 3D linear regression through principal component analysis (PCA). Various feature-based approaches (RANSAC, least-square fitting, Hough transform) have been compared for best matching the contours and the centers of the holes on the tomograms. The robustness of the suggested method was investigated using simulations. Programming is done in Matlab™ and C ++. Results obtained on synthetic data confirm very good localization accuracy – mean translational error of 0.14 mm (std = 0.08 mm) and mean angular error of 0.84° (std = 0.35°) at no radiation excess. Successful localization can be further used to guide a surgeon or a robot for correct drilling the bone along the nail openings.

Micro-computed tomography (μCT) is a new kind of nondestructive technique, which provides high resolution images of the internal structure of small objects or samples, being a powerful imaging modality for small animals. The aim of this study was to investigate the quality of generalized Feldkamp algorithm for helical μCBCT in rodent imaging. For this study, μCT projections of a digital (voxelized) phantom approximating the mouse were simulated for three different helical pitch factors of 0.5, 1 and 2. Due to its modest computational requirements and relative ease of implementation, a generalized FDK algorithm was used for 3D volume reconstruction. For the voxelized mouse phantom, 1024×1024×2048 pixels volumes were reconstructed for all helical pitches. The normalized mean square errors (NMSE) were computed in all three directions (x, y, z) as objective image characteristic. Although the NMSE slightly increase for the pitch factor of 2, the overall image quality of reconstructed tomograms is comparable with the one obtained using a pitch factor of 0.5: soft tissue can be clearly distinguished from bones; lungs, heart and intestines can be identified on the on the reconstructed tomograms. Based on the above observation we can state that using pitch factor of 2 is preferable in longitudinal studies of small animal, to reduce significantly the radiation dose.

Closed intramedullary nailing is the common technique for treatment of femur and tibia fractures. The most challenging step in this procedure is the precise placement of the lateral screws that stabilize the fragmented bone.

The purpose of this study was to investigate and compare microcalcification detectability using Digital Tomosynthesis (DTS), Dual Energy Mammography (DEM) and Cone Beam Computed Tomography (CBCT) with a flat-panel detector. A simulated 3D uncompressed breast approximating the medium sized breast, with 50% adipose and 50% glandular tissue was used. Microcalcifications were modeled as calcium carbonate spheres/ellipsoids with size in full range of 0.1 to 1mm. An amorphous-silicon CsI flatdetector, 2048 × 2048 mm2 at 0.1mm resolution was modeled. Images from the above phantom were simulated using three acquisition protocols for DTS, DEM and CBCT. For DTS, projections data were acquired for an acquisition arc from −200 to 200 with 20 sampling step, and the 3D reconstructed volume was obtained using a Multiple Projection Algorithm (MPA), with a 0.1 mm width between successive tomograms. In the DEM case, two synthetic projection images at 21 and 52 KeV respectively were simulated. A weighted subtraction of low and high — energy digital X-ray images was performed, allowing the removal of background morphology and enhancement of the obscured details. For the last method (CBCT), 181 projections acquired every 20 over a full circular scanning path were used for 3D breast volume reconstruction using the well-known FDK algorithm. The image quality of the reconstructed tomograms was visually assessed and quantified in terms of contrast to noise ratio (CNR), relative detail contrast (RC), as well as Artifacts Spread Function (ASF). The results show that microcalcifications with diameter equal or greater than 0.1mm can be detected, with the CBCT and DTS techniques. Superior quality is demonstrated by CBCT technique in comparison with DTS and DE by means of better microcalcification detection.

This paper shows how unique behavioural walking identification properties can be used to recognise unauthorised and suspicious persons when they enter a surveillance/recognition area. Specific gait properties will be examined in order to make clear the impact in the recognition accuracy. The system that is proposed comprise of various parts that operate either as stand alone capacities or as an integral part of a greater system. The two main entities of the system are the gait recognition and the information analysis module. The intelligent automated process in the information analysis enforces the public safety authorities to make simultaneous threat assessments based on complex search queries. The information and the functionalities of the system are delivered to the user through an integrated software solution that provides transparency for the majority of security operations. The integrated solution can be used for real time monitoring as well as for access control at sites of high risk.

This paper presents a computer-based system dedicated to x-ray phase contrast (PhC) imaging research. It consists of two main modules: (a) a module for generation of x-ray PhC images from computational phantoms and (b) a module for image reconstruction. The module for generation of x-ray images consists of submodules dedicated to modelling of computational phantoms, modelling the image acquisition geometry and formation of x-ray images. The module for image reconstruction is a software tool, based on an in-house built reconstruction techniques class library, which is a dedicated object-oriented library for x-ray based applications. The computer-based system is tested for its feasibility to generate correctly PhC projection images and to reconstruct from them, considering a breast tomosynthesis setup. Two computational phantoms were designed for the simulations: a 4 cm thick polymethyl methacrylate phantom with air channels and a 2 cm thick rectangular polystyrene flask filled with epoxy resin mixture. Images in a tomosynthesis mode were generated and tomograms were calculated by using the reconstruction module. Simulations were validated with the help of experimental study conducted at beamline ID17, ESRF. Results show good visual agreement between simulated and experimentally obtained images. The platform, after its complete evaluation, may be useful in studying new x-ray imaging techniques based on phase contrast. Applications are foreseen also in education and training.

Computer-assisted surgical devices, including laparoscopic surgical robotic arms, can be used in urologic surgery to minimize trauma. In this study, we explored the feasibility and applicability of using a robotic arm, AESOP (Computer Motion Inc, Goleta, CA), as a substitute for surgical assistants during hand-assisted laparoscopic nephrectomies in humans. Four patients (3 men and 1 woman, mean age 66 years) underwent robotic-assisted laparoscopic nephrectomy. The hand-assisted laparoscopic nephrectomy was completed successfully in all patients. The average operative time, estimated blood loss, and time to hospital discharge was 252.5 minutes, 0.57 ml, and 4.5 days, respectively. Postoperative satisfactory function was confirmed through laboratory tests, imaging exams and biochemical tests. No complications were reported for any of the patients. Parameters, such as the operative time, are expected to be further reduced when more experience with the use of the robot has been acquired. In conclusion, robotic-assisted laparoscopic nephrectomy is feasible and safe, and can be performed without complications. The potential long-term cost effectiveness of using robotic surgical assistants in laparoscopic surgery highlights the economic impact of this research and warrants further investigation.