X-ray imaging

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Development of Hard X ray Imaging Detectors for the High Energy Focusing Telescope

Development of Hard X ray Imaging Detectors for the High Energy Focusing Telescope

Development of hard X-ray imaging detectors for the High Energy Focusing Telescope Thesis by Chi Ming Hubert Chen In Partial Ful... llment of the Requirements for the Degree of Doctor of[r]

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Augmented Reality Advancement X-Ray Imaging Medical Reality scanning

Augmented Reality Advancement X-Ray Imaging Medical Reality scanning

The main objective of this research article is to use Augmented Reality for medical imaging for advancement in Images developed from Ultrasound Scans,and microscopy images to be combined with videos. This combination of Scan Images mediated with video and audio enables the viewing of fetus moments to be incorporated as an video in the image to be watched by the medical consultant for all its sensory movements. This paper is designed with the intention to develop augmented reality to combine real time images of fetus with its actual videos showing its gestures, movements, and posture inside the uterus. This showcases the Doctors to examine patients while viewing superimposed medical images. In addition, this augmented reality mobile applications can provide the surgeon with certain essential information, which are usually not visible such as showing heartbeat, blood pressure. This application let a doctor by looking into images such an X-ray combined with the patients photograph, disease name ,symptoms and even videos. For example ,All these helps the specialist in visualizing the position of a tumor in the video of an endoscope or radiation exposure risks from X-ray Imaging devices.
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Investigation and Application of High Megavoltage X Ray Imaging Mode in Radiotherapy

Investigation and Application of High Megavoltage X Ray Imaging Mode in Radiotherapy

because tumors may threaten human life. Radiotherapy is one of the three significant therapy strategies for the cancer treatment. Now, the radiotherapy has entered new era of accurate treatment with applying 3D conformal and Intensity-modulated therapy (IMRT) [1] [2]. Chen [3] stated tumor’s verification image during radiotherapy period is an essential process and Imaging Guide Radiotherapy Therapy (IGRT) is a new developed system for ensuring tumor to be irradiated at precise position. Currently, kV level imaging mode (kV) and MV level imaging mode (MV) imaging modes are two main X-ray imaging modes for IGRT on linear accelerators for radiation therapy [4] [5]. Their X-ray energy ranges from 60 kV to 120 kV and 4MV to 15 MV respectively. However, both of these modes have unavoidable shortcoming and inadequate.
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Germination of Corylopsis seeds evaluated by X-ray imaging and cold stratification

Germination of Corylopsis seeds evaluated by X-ray imaging and cold stratification

Percentage of seeds of C. sinensis var. calvescens that sank in water for 16 h germination were in- creased to 45% after the first CS (1 CS), as com- pared to 12% without CS. Based on the X-ray im- ages and immersing seeds in water, most of the full and mostly full seeds of C. coreana and C. sinensis var. calvescens germinated. Furthermore, X-ray imaging may be very useful to separate vi- able seeds from non-viable seeds on a large scale. Based on seed weights, X-ray images, and germi- nation percentages for seeds harvested over time, it is concluded that seeds harvested after Sept. 20 are mature. Dormancy in Corylopsis is composed of physiological dormancy imposed by the embryo/ endosperm, which can be overcome without CS, and physical dormancy imposed by the seed coat, which can be released by immersing seeds in water for 16 hours. These two types of dormancy may be involved in germination, especially in C. sinensis var. calvescens. A few seeds germinate without CS; however, to increase germination, 2 months of CS at 5°C treatment is recommended.
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Monte Carlo modeling of direct x-ray imaging systems

Monte Carlo modeling of direct x-ray imaging systems

We conducted an image evaluation exercise as a demonstration of the model utility. The goal of of the exercise was to investigate the effect of fill factor and electronic noise at different pixel sizes on the ability to detect objects present in x-ray images. X-ray images utilized in the exercise were produced with the model described in this thesis. Two phantoms (targets) were used. The first phantom was an acrylic disc with a 6.25 mm diameter and a 1.85 mm height. These dimensions result in the disc having a 12% contrast. The second phantom was a grouping of six discs each with a 0.4 mm diameter and a 0.6 mm height that resemble microcalcifications present in breast tissue. Both phantoms represent objects radiologists look for when screening for breast cancer in women and are commonly used in evaluating x-ray imaging systems designed for mammography applications.
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Machine vision image quality measurement in cardiac x-ray imaging

Machine vision image quality measurement in cardiac x-ray imaging

Iodine contrast is clearly not the only important aspect of image quality for cardiac imaging. Image noise, spatio-temporal resolution properties, and the application of specialist image process are also critically important. We selected iodine contrast for our initial investigation, as the x-ray imaging system has several convenient degrees of freedom by which to influence it, including the x-ray tube voltage (kVp), x-ray beam filtration, the source-to-detector distance (which influences scatter and, therefore, contrast), and the anti-scatter grid.
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Improved non-destructive 2D and 3D X-ray imaging of leaf venation

Improved non-destructive 2D and 3D X-ray imaging of leaf venation

A gold mask with standardized line pairs and edged dot patterns was used as a control of the quality of the X-ray imaging methods (for example, to verify that resolution was 7  µm in our high-resolution 2D X-ray approach). Because nominal resolution of each of the X-ray meth- ods is not necessarily the same as their resolution of the leaf venation (due to the properties of the biological tis- sue such as the impact of leaf texture; see Background section), especially of the finest veins, we additionally assessed differences between methods using a quanti- tative approach. We selected vein density as a measure that depends on the quality of the vein display. We cal- culated the vein density in 5–10 rectangles with identical position and size using the same leaf fragment for each taxon (for example, we compared 2D X-ray imaging with 25  µm resolution with that of 7  µm; Additional file  1: Fig. S1). To obtain vein density values, the length of all veins in each of the areas was traced digitally and meas- ured using ImageJ [22] and the plugin ObjectJ, version 1.03x [23]. Digital tracing is still the method of choice and proved more accurate than semiautomatic measure- ments with LeafGUI [5, 24]. Significance of differences in vein density measurements between the different imag- ing methods was assessed with a paired t test in R [25]. A quantitative comparison of micro CT images with those obtained from chemically cleared leaves was hampered by the slight sample distortion during preparation that led to size differences of the objects. Therefore, we opted primarily for a visual comparison, verifying vein connec- tivity and the presence of vein orders.
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Geometric nonlinear diffusion filter and its application to X-ray imaging

Geometric nonlinear diffusion filter and its application to X-ray imaging

Image denoising is very important in digital x-ray imaging since it may allow us to reduce x-ray dose in human subjects without noticeable degradation of the image qual- ity. Owing to the advent of 2D flat-panel x-ray detector, digital x-ray imaging modal- ities like digital radiography (DR) or 3D cone-beam CT are now widely used for clinical imaging [1,2]. Taking x-ray images with low x-ray dose is always desired due to the hazardous biological effects of x-rays. However, low dose x-ray images may suffer from high level noises stemming from randomness of x-ray photon fluence and detec- tor noise. There have been many developments of denoising filters that can be used to improve signal-to-noise ratio (SNR) of x-ray images without compromising the image resolution to a noticeable extent [3-5]. In denoising x-ray images, it is critical not to lose detailed spatial information in the original images which is crucial for accurate diagnosis. Recent developments of non-linear iterative denoising filters make it possible to remove noise from the x-ray images while maintaining edge features, which is
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Automatic unhulled rice grain crack detection by X-ray imaging

Automatic unhulled rice grain crack detection by X-ray imaging

In recent years, xray imaging techniques have proven useful for many agricultural product inspection applications. Thomas et al. (1995) developed a non‐destructive xray in‐ spection method to detect weevil‐infested mango fruits. Xray images of pistachio nuts containing only nut meat were obtained by digitizing the xray films using a film scanner (Casasent et al., 2001). A computer vision system capable of detecting pin holes due to insect damage in almonds was studied by Kim and Schatzki (2001). Tao et al. (2001) de‐ tected foreign objects present in deboned poultry. In addition to these studies, soft x‐rays have been used extensively for detection of internal defects caused by insect infestation in wheat kernels (Karunakaran et al., 2003a, 2003b, 2004; Haff and Slaughter, 2002, 2004).
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Context sensitive cardiac x-ray imaging: a machine vision approach to x-ray dose control

Context sensitive cardiac x-ray imaging: a machine vision approach to x-ray dose control

Abstract. Modern cardiac x-ray imaging systems regulate their radiation output based on the thickness of the patient, to maintain an acceptable signal at the input of the x-ray detector. This approach does not account for the context of the examination, or the content of the image displayed. We have developed a machine vision algorithm that detects iodine filled blood vessels and fits an idealized vessel model with key parameters of contrast, diameter and linear attenuation coefficient. The spatio-temporal distribution of the linear attenuation coefficient samples, when arranged appropriately, can be described by a simple linear relationship, despite the complexity of scene information. The algorithm was tested on static anthropomorphic chest phantom images under different radiographic factors and 60 dynamic clinical image sequences. It was found to be robust, and sensitive to changes in vessel contrast resulting from variations in system parameters. The machine vision algorithm has the potential of extracting real-time context sensitive information that may be used to augment existing dose control strategies.
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Understanding automated dose control in dynamic X-ray imaging systems

Understanding automated dose control in dynamic X-ray imaging systems

After each fluoroscopy run, the patient thickness is updated via calculation within the system. This calculation is performed at the end of each fluoroscopy run to account for changes in effective patient thickness, and begins the described process again. For example, if the image projection (gantry angle) changes, the effective patient thickness changes, and radiographic factors must be adjusted accordingly. The distance between the X-ray source and patient is not taken into account for the patient thickness calculation. Therefore, patient table height does not have an impact on operation of the ADRC. The patient thickness calculation is used to adjust radiographic factors when a fluoroscopy run is captured after a change in effective patient thickness. If only the SID or image field of view (FOV) is changed, radiographic factors are updated without the need for a fluoroscopy run.
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Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures

Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures

Al-Si samples for phase contrast imaging were prepared by the Materials Preparation Center at Ames Laboratory, with a composition of 50 wt% Si for the LWFA experiment and 30 wt% for the SLS experiment. Although the Al-Si sample used in the LWFA experiment had 20% more Si than that used in the SLS experiment, this excess Si is associated not with the Al-Si eutectic but rather the primary (i.e., pro-eutectic) Si phase. The larger mass fraction of this primary Si phase in the Al-Si alloy used in these experiments clouded the field-of-view in the X-ray images, limiting the eutectic — which is last to solidify — to a smaller region of the sample. However, this has little to no bearing on the development of the eutectic microstructure. Both alloys were cast in the exact same manner, and thus have comparable lamellar spacings (see Methods). For both experiments, the samples were machined into cylindrical samples of 1 mm thickness.
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Illustrating the effect of viscoelastic additives on cavitation and turbulence with X-ray imaging

Illustrating the effect of viscoelastic additives on cavitation and turbulence with X-ray imaging

Figure 3 presents post-processed radiographs illustrating the form and evolution of vaporous structures along the orifice length. The white line corresponds to the liquid vapour interface. It should also be noted that the grey spots evident in Fig. 3 (regions corresponding to X = 1.0 mm and X = 2.0 mm) cover artefacts present in the radiographs caused by imperfections of the scintillator crystal that have arisen due to prolonged exposure to the high-flux X-ray beam. For a needle lift equal to 0.5 mm (Fig. 3a), elongated vaporous structures occupy the entire length, i.e. string cavitation constitutes the prevailing regime. A pair of cavities is clearly discernible, with the two structures interacting as the cavitation number increases. Moderate vapour generation is also observed attached to the wall in the vicinity of the nozzle entrance, especially at the side from which the main flow enters the orifice (lower side of the figures). Vapour formation in the wall region indicates that flow separation does occur downstream the geometrical constriction, nevertheless it is not of considerable magnitude and extent so as to give rise to a well-established cloud cavity. On the contrary, for needle lift equal to 1.0 mm, an attached cloud cavity establishes at the orifice entrance region and occupies the entire orifice cross-section. Cases characterised by higher cavitation numbers (not depicted in Fig. 3b for brevity) have verified that the cloud cavity expands further to the downstream and the cloud becomes unstable at the closure region with vortical structures being shed at high frequencies.
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System Characterizations and Optimized Reconstruction Methods for Novel X-ray Imaging

System Characterizations and Optimized Reconstruction Methods for Novel X-ray Imaging

Figure 4.7(a) shows the reconstructed image of the central vertical slice of the phantom from the 30-view data set and by use of the FBP algorithm. The reconstructed voxel size was 0.1 mm. There can be observed significant aliasing and beam hardening artifacts, due to the insufficient angular sampling and the effects of polychromatic spectrum, as well as consid- erable noise corruption. The shapes of the reconstructed spheres are obviously elongated, by comparison to the ground truth in Fig. 4.6(a), and therefore the scout-scan reconstruc- tion cannot be used to reflect the true sizes of the calcifications. However, the outermost boundaries between the phantom and air can still be reliably reconstructed, because the attenuation properties of the two are quite different. A simple thresholding method was used to extract the total-projection-length of the phantom along the X-ray beam direction from the reconstructed image corresponding to Fig. 4.7(a). The extracted total-projection- length and the true phantom length are plotted in Fig. 4.7(b), showing the high accuracy of phantom-air boundary differentiation. Note that the two curves do not exactly coincide. There is still an error in the estimate of the total-projection-length by use of the scout scan, which can be up to 0.5 mm in this study.
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Evaluation of moisture content distribution in wood by soft X-ray imaging

Evaluation of moisture content distribution in wood by soft X-ray imaging

When samples were dried in several steps in a drying chamber and soft X-ray images were taken in each step, the relationship between oven-dry moisture content of each sample and the average grayscale value of the soft X-ray image was linear. In addition, the plots of the three sample types overlapped each other regardless of sample sections. Applying this relationship to a small section of a sample, the moisture content distribution of the entire sample area of 100 × 100 mm was estimated nondestructively from the D image from the soft X-ray pictures of the sample in question
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Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures

Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures

One exciting application for these novel X-ray sources is as a diagnostic tool for additive manufacturing processes. Laser-aided solidification is an avenue of interest in manufacturing science that requires in situ measurements with high spatial and temporal resolution 20, 21 . Such is the case for the solidification of eutectics, in which two (or more) solid phases grow simultaneously from a parent liquid phase 22–25 . Once solidified, eutectics act as in situ composite materials, providing outstanding mechanical and electrical properties that are not afforded by their constituent phases alone. It is for this reason that lightweight Al-Si alloys comprise over 90% of the total Al parts produced by the United States 26 . Irregular eutectics such as Al-Si are composed of one faceted phase (Si) and another non-faceted (Al) phase. Due to the stiffness of the faceted phase, irregular eutectics feature a non-periodic arrangement of lamellae (fine rods or sheets of adjacent material). The interfacial dynamics underlying irregular eutectic solidification (under relatively low cooling rates) has only recently been elucidated through synchrotron-based X-ray microtomography (denoted XRT), using conventional accelerators. 27 . In general, the lamellar spacing (between Al and Si phases) can be as fine as 1 µm, thus requiring experimental probes that are capable of delivering high resolution information.
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Global Localization and Orientation of the Cervical Spine in X-ray Imaging

Global Localization and Orientation of the Cervical Spine in X-ray Imaging

Our algorithms outperformed the performances of [3, 4]. [3] reported an av- erage orientation error of 4.16 degree and [4] reports a vertebra detection 89%. However, [3] report only 10% landmark points to be outside the bounding box which is lower than our 12%. But their landmark points did not consider the posterior points. It is also important to mention that both of these works, has been performed on a small (40 and 50) images from NHANES-II dataset of scanned X-ray images, where the images are collected from healthy patients for the purpose of developing automatic algorithms thus contains less variation, in- juries and exposure differences. In our case, the dataset represents X-ray images collected from real life emergency room images where resolution, patient age, injury, orientation, X-ray exposure all vary widely. Fig. 4 shows examples of im- ages with low contrast (h, i), bone implants (f, l, n), displacements (j, m) and osteoporosis (d, k). Our algorithm works well in all these conditions.
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Challenges associated with x ray imaging of stretcher bound patients

Challenges associated with x ray imaging of stretcher bound patients

Comparisons were established by calculating the aluminium (Al) equivalent of the mattresses in order to determine their radiation transmission capabilities. NICE estimated that the low attenuating x-ray mattress was 0.2mm Al equivalent whereas the x-ray stretcher mattress was 1.0mm Al equivalent. Surprisingly, NICE did not specify the make, type, or thickness of the mattresses used in their comparisons. It is therefore difficult to generalise and put this information into context since there are several commercially available mattresses for x-ray tabletops and stretchers on the market. In addition, manufacturers do not ordinarily specify the Al equivalent of their mattresses therefore it is also difficult to compare these estimations from the NICE guidelines to the mattresses described in Table 2. NICE comment that the mattress in question did not affect x-ray image quality or radiation dose however this was based on observations made by users confirming that clinical practice had not changed when using this new mattress. NICE conducted a small experiment to determine the effect of the new warming mattress on image quality, however there were no details on how image quality was assessed. The lack of scientific evidence for the assumptions made by NICE regarding the effect of the mattresses under question makes it difficult to interpret and transfer to clinical practice. This example above highlights that products can easily be deemed
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Characteristics of the CsI:Tl Scintillator Crystal for X Ray Imaging Applications

Characteristics of the CsI:Tl Scintillator Crystal for X Ray Imaging Applications

In order to determine the ideal thickness of the slices of the scintillator crystal CsI:Tl, Monte Carlo method was used. The absorption of the X-ray energies in the scintillator was estimated by the Monte Carlo method. This method simu- lates all occurrences of gamma radiation interaction in the material media. The following interactions of the electromagnetic radiation taken into account were: Photoelectric effect, Compton scattering and Rayleigh scattering. Based on these interactions, a program was developed to simulate the interactions in the scintil- lator block and to estimate the level of absorption of the radiation X, as a func- tion of the dimensions of the scintillator. Figure 2 shows the main panel of the program.
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A 0.18µm CMOS Low-Power Charge-Integration DPS for X-Ray Imaging

A 0.18µm CMOS Low-Power Charge-Integration DPS for X-Ray Imaging

applications: mammography Si or CdTe X-ray sensor V com CMOS circuit X-ray particle hit bump bonding digital X-ray imager DPS e/h cloud - + I sens I sens time.. I Novel X-ray DPS proposa[r]

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