Two-dimensional X-ray Images Research Articles

3차원 정보 제공을 위한 X-선 검색장치의 기하학적 모델링

In this study, to clearly establish the concept of a geometric modeling I apply for the concept of Pushbroom, limited to two-dimensional radiation Locator to provide a three-dimensional information purposes. Respect to the radiation scanner Pushbroom modeling techniques, geometric modeling method was presented introduced to extract three-dimensional information as long as the rotational component of the Gamma-Ray Linear Pushbroom Stereo System, introduced the two-dimensional and three-dimensional spatial information in the matching relation that can be induced. In addition, the pseudo-inverse matrix by using the conventional least-squares method, GCP(Ground Control Point) to demonstrate compliance by calculating the key parameters. Projection transformation matrix is calculated for obtaining three-dimensional information from two-dimensional information can be used as the primary relationship, and through the application of a radiation image matching technology will make it possible to extract three-dimensional information from two-dimensional X-ray imaging.

High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images

Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions ≈ 16.2 μm). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using this technique, it is possible to measure changes in regional lung volume at high spatial and temporal resolution during breathing at much lower x-ray dose than would be required using computed tomography.

Quantitative Analysis Methods for Adapting Image J programs on Mouse Calvarial defected Model

This mouse calvarial defected model is frequently used for new scaffold development in the bone regeneration. Most experiments are carried out in this way by measuring the bone regeneration of mouse calvaria defected area. As a next step, hematoxylin and eosin staining is analyzed by sacrificing mice On the other hand, the quantitative analysis for bone regeneration is carried out by micro computed tomography. However, there are several drawbacks with the micro computed tomography. That is, it takes a long time and it is quite expensive for bone regeneration quantitative analysis. This study was performed by simply measuring the quantity of bone regeneration in mouse clavaira defected area on two-dimensional digital x-ray images via Image J. Consequentially, this experimental method by using J program might help bio-technologist researcher regarding new bone regeneration by comparing the quantity of bone regeneration quickly and precisely as well.

The Fate of ZnO Nanoparticles Administered to Human Bronchial Epithelial Cells

A particular challenge for nanotoxicology is the evaluation of the biological fate and toxicity of nanomaterials that dissolve in aqueous fluids. Zinc oxide nanomaterials are of particular concern because dissolution leads to release of the toxic divalent zinc ion. Although zinc ions have been implicated in ZnO cytotoxicity, direct identification of the chemical form of zinc taken up by cells exposed to ZnO nanoparticles, and its intracellular fate, has not yet been achieved. We combined high resolution X-ray spectromicroscopy and high elemental sensitivity X-ray microprobe analyses to determine the fate of ZnO and less soluble iron-doped ZnO nanoparticles following exposure to cultures of human bronchial epithelial cells, BEAS-2B. We complemented two-dimensional X-ray imaging methods with atomic force microscopy of cell surfaces to distinguish between nanoparticles that were transported inside the cells from those that adhered to the cell exterior. The data suggest cellular uptake of ZnO nanoparticles is a mechanism of zinc accumulation in cells. Following uptake, ZnO nanoparticles dissolved completely generating intracellular Zn(2+) complexed by molecular ligands. These results corroborate a model for ZnO nanoparticle toxicity that is based on nanoparticle uptake followed by intracellular dissolution.

Bioequivalence and X-Ray Visibility of a Radiopaque Etonogestrel Implant versus a Non-Radiopaque Implant

The etonogestrel (ENG)-releasing implant is a subdermal progestogen-only contraceptive that provides coverage for up to 3 years. This long-acting hormonal contraceptive has been available in Europe since 1998 and in the US since 2006. To date, localization of non-palpable implants at insertion and before removal has been dependent on ultrasound or magnetic resonance imaging by an experienced clinician. To facilitate localization in rare cases of non-palpable implants using widely available equipment without the need for a specialist, a radiopaque ENG implant has been developed that is detectable by two-dimensional x-ray imaging. This study aimed to establish whether the radiopaque ENG implant is bioequivalent in situ compared with the original non-radiopaque ENG implant, and to assess x-ray visibility of the radiopaque ENG implant. This was a 3-year, randomized, double-blind, parallel-group study carried out in nine international clinical trial centres. Women aged 18-40 years at the time of screening, with menstrual cycles of a usual length of 24-35 days and a body mass index of between ≥18 and ≤29 kg/m(2) were included. Women were assigned to either the radiopaque or non-radiopaque ENG implant in a 1 : 1 ratio via a block randomization by centre. Bioequivalence testing was performed based on the peak ENG concentration (C(max)), and the area under the curve (AUC) for ENG at 6, 24 and 36 months (AUC(6 mo), AUC(24 mo) and AUC(36 mo)) after insertion. For this purpose, blood sampling for pharmacokinetic determination was performed prior to insertion and for up to 3 years afterwards. Bioequivalence was defined as the 90% confidence interval (CI) of the ratio radiopaque implant/non-radiopaque implant of the geometric means (GMR) within the acceptance range of 0.80-1.25. x-Ray visibility was assessed by two-dimensional x-ray imaging after insertion and before removal of the implant. The pharmacokinetic profiles of ENG indicated that the radiopaque and non-radiopaque implants were bioequivalent with respect to the geometric mean of C(max) (GMR 1.06; 90% CI 0.91, 1.23), AUC(6 mo) (GMR 1.00; 90% CI 0.91, 1.10), AUC(24 mo) (GMR 0.98; 90% CI 0.88, 1.10) and AUC(36 mo) (GMR 1.00; 90% CI 0.89, 1.11). The radiopaque ENG implant was clearly visible in 50 out of 52 women after insertion and in all 52 women before removal, whereas none of the non-radiopaque implants were visible. The radiopaque ENG implant is bioequivalent in situ compared with the original non-radiopaque ENG implant and is clearly visible using x-ray imaging. Registered as ClinicalTrials.gov identifier NCT00620464.

X-ray tomographic image of a deposit on a spherical surface

A method has been developed to obtain two-dimensional X-ray tomographic images of deposit objects located on bent mirror surfaces. A procedure that makes it possible to obtain two-dimensional X-ray image of an object (fingerprint) located on the surface of a spherical mirror has been proposed and experimentally implemented. Mathematical algorithms for reconstructing images have been developed.

Parametric modelling and segmentation of vertebral bodies in 3D CT and MR spine images

Accurate and objective evaluation of vertebral deformations is of significant importance in clinical diagnostics and therapy of pathological conditions affecting the spine. Although modern clinical practice is focused on three-dimensional (3D) computed tomography (CT) and magnetic resonance (MR) imaging techniques, the established methods for evaluation of vertebral deformations are limited to measuring deformations in two-dimensional (2D) x-ray images. In this paper, we propose a method for quantitative description of vertebral body deformations by efficient modelling and segmentation of vertebral bodies in 3D. The deformations are evaluated from the parameters of a 3D superquadric model, which is initialized as an elliptical cylinder and then gradually deformed by introducing transformations that yield a more detailed representation of the vertebral body shape. After modelling the vertebral body shape with 25 clinically meaningful parameters and the vertebral body pose with six rigid body parameters, the 3D model is aligned to the observed vertebral body in the 3D image. The performance of the method was evaluated on 75 vertebrae from CT and 75 vertebrae from T2-weighted MR spine images, extracted from the thoracolumbar part of normal and pathological spines. The results show that the proposed method can be used for 3D segmentation of vertebral bodies in CT and MR images, as the proposed 3D model is able to describe both normal and pathological vertebral body deformations. The method may therefore be used for initialization of whole vertebra segmentation or for quantitative measurement of vertebral body deformations.

Experimental X-ray characterization of Gekko-XII laser propagation through very low-density aerogels (2–5 mg/cc) creating multi-keV photons from a titanium solid foil

This work describes measurements of laser propagation through very low-density aerogels and subsequent multi-keV photon production from titanium foils. For efficient foil heating, SiO 2 aerogel with densities of 2 and 5 mg/cm 3 have been cast into a plastic cylinder, which are then mounted to Ti foils that are 3–20 μm thick. Experiments have been performed on the GEKKO-XII laser facility to characterize laser propagation through the aerogel and X-ray production from the Ti foil. Multi-keV emission is diagnosed with a full set of diagnostics giving laser-to-X-ray conversion efficiencies, time-dependent X-ray power and two-dimensional X-ray imaging.

Registration of 3D trans-esophageal echocardiography to X-ray fluoroscopy using image-based probe tracking

Two-dimensional (2D) X-ray imaging is the dominant imaging modality for cardiac interventions. However, the use of X-ray fluoroscopy alone is inadequate for the guidance of procedures that require soft-tissue information, for example, the treatment of structural heart disease. The recent availability of three-dimensional (3D) trans-esophageal echocardiography (TEE) provides cardiologists with real-time 3D imaging of cardiac anatomy. Increasingly X-ray imaging is now supported by using intra-procedure 3D TEE imaging. We hypothesize that the real-time co-registration and visualization of 3D TEE and X-ray fluoroscopy data will provide a powerful guidance tool for cardiologists. In this paper, we propose a novel, robust and efficient method for performing this registration. The major advantage of our method is that it does not rely on any additional tracking hardware and therefore can be deployed straightforwardly into any interventional laboratory. Our method consists of an image-based TEE probe localization algorithm and a calibration procedure. While the calibration needs to be done only once, the GPU-accelerated registration takes approximately from 2 to 15s to complete depending on the number of X-ray images used in the registration and the image resolution. The accuracy of our method was assessed using a realistic heart phantom. The target registration error (TRE) for the heart phantom was less than 2mm. In addition, we assess the accuracy and the clinical feasibility of our method using five patient datasets, two of which were acquired from cardiac electrophysiology procedures and three from trans-catheter aortic valve implantation procedures. The registration results showed our technique had mean registration errors of 1.5-4.2mm and 95% capture range of 8.7-11.4mm in terms of TRE.

Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data

Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data is not a trivial task because of their fundamental difference in tissue contrast. This paper presents a technique that generates pseudo-computed tomography (CT) data from multi-spectral MRI acquisitions which is sufficiently similar to real CT data to enable registration of x-ray to MRI with comparable accuracy as registration of x-ray to CT. The method is based on a k-nearest-neighbors (kNN)-regression strategy which labels voxels of MRI data with CT Hounsfield Units. The regression method uses multi-spectral MRI intensities and intensity gradients as features to discriminate between various tissue types. The efficacy of using pseudo-CT data for registration of x-ray to MRI was tested on ex vivo animal data. 2D–3D registration experiments using CT and pseudo-CT data of multiple subjects were performed with a commonly used 2D–3D registration algorithm. On average, the median target registration error for registration of two x-ray images to MRI data was approximately 1 mm larger than for x-ray to CT registration. The authors have shown that pseudo-CT data generated from multi-spectral MRI facilitate registration of MRI to x-ray images. From the experiments it could be concluded that the accuracy achieved was comparable to that of registering x-ray images to CT data.

Development of a three-dimensional tactile sensor for minimally invasive instruments

This paper proposes a three-dimensional tactile sensor that can be attached to the tip of an endoscope or catheter to detect the tip contact conditions. Because conventional minimally invasive instruments (MIIs) without a sensor cannot detect the posture and applied force at the tip, operators cannot obtain accurate information during minimally invasive surgery (MIS). The sensor consists of an elastic cylinder and three strain g auges. The gauges, located on the surface of the cylinder at intervals of 120 � , are used to detect deformation of the cylinder caused by contact with the inner walls of the patient's organs. The output voltage signals of the gauges are approximated by a sinusoidal function with a phase difference of 120 � . The three-dimensional contact angle and applied force at the tip of the sensor can be estimated accurately from the three sinusoidal functions and measured output voltage signal from the gauges. The operating principle of the sensor is examined through several experimental conditions. To improve the effectiveness of minimally invasive surgery (MIS), it is necessary to develop better endoscope and catheter techniques. Conventional minimally invasive instruments (MIIs) improve the quality of life (QOL) of patients, because they can begin rehabilitation only a few days after MIS. However, the manipulation of MIIs is difficult because opera tors cannot obtain accurate information about the tip contact conditions of MIIs with the walls of the patient's organs. In conventional MIS, the operator manipulates the MII based on both the tactile sensations transmitted to their hand via the MII and the two-dimensional X-ray image information. However, tactile sensations are a mixture of the contact and friction forces with the walls of organs, and it is difficult to discriminate these forces precisely. Therefore, operators need to be highly trained; a lack of this skill on their part may lead to critical accidents. The abovementioned issues have necessitated the development of mechanisms for detecting the posture of the MII tip. Some active devices (1-4) have been developed to help manipulate catheters (3) and endoscopes (4). In these devices, shape memory alloys (SMAs) are used as actuators. In addition, inchworm locomotion (5) has been developed. An inchworm-like robot with a bellows mechanism

Monochromatic x-ray radiography for areal-density measurement of inertial fusion energy fuel in fast ignition experiment

Ultrafast, two-dimensional x-ray imaging is an important diagnostics for the inertial fusion energy research, especially in investigating implosion dynamics at the final stage of the fuel compression. Although x-ray radiography was applied to observing the implosion dynamics, intense x-rays emitted from the high temperature and dense fuel core itself are often superimposed on the radiograph. This problem can be solved by coupling the x-ray radiography with monochromatic x-ray imaging technique. In the experiment, 2.8 or 5.2 keV backlight x-rays emitted from laser-irradiated polyvinyl chloride or vanadium foils were selectively imaged by spherically bent quartz crystals with discriminating the out-of-band emission from the fuel core. This x-ray radiography system achieved 24 μm and 100 ps of spatial and temporal resolutions, respectively.

2D soft x-ray system on DIII-D for imaging the magnetic topology in the pedestal region

A new tangential two-dimensional soft x-ray imaging system (SXRIS) is being designed to examine the edge island structure in the lower X-point region of DIII-D. Plasma shielding and/or amplification of the calculated vacuum islands may play a role in the suppression of edge-localized modes via resonant magnetic perturbations (RMPs). The SXRIS is intended to improve the understanding of three-dimensional (3D) phenomena associated with RMPs. This system utilizes a tangential view with a pinhole imaging system and spectral filtering with beryllium foils. SXR emission is chosen to avoid line radiation and allows suitable signal at the top of a H-mode pedestal where T(e)∼1-2 keV. A synthetic diagnostic calculation based on 3D SXR emissivity estimates is used to help assess signal levels and resolution of the design. A signal-to-noise ratio of 10 at 1 cm resolution is expected for the perturbed signals, which are sufficient to resolve most of the predicted vacuum island sizes.

Echocardiography to magnetic resonance image registration for use in image-guided cardiac catheterization procedures

We present a robust method to register three-dimensional echocardiography (echo) images to magnetic resonance images (MRI) based on anatomical features, which is designed to be used in the registration pipeline for overlaying MRI-derived roadmaps onto two-dimensional live x-ray images during cardiac catheterization procedures. The features used in image registration are the endocardial surface of the left ventricle and the centre line of the descending aorta. The MR-derived left ventricle surface is generated using a fully automated algorithm, and the echo-derived left ventricle surface is produced using a semi-automatic segmentation method provided by the QLab software (Philips Healthcare) that it is routinely used in clinical practice. We test our method on data from six volunteers and four patients. We validated registration accuracy using two methods: the first calculated a root mean square distance error using expert identified anatomical landmarks, and the second method used catheters as landmarks in two clinical electrophysiology procedures. Results show a mean error of 4.1 mm, which is acceptable for our clinical application, and no failed registrations were observed. In addition, our algorithm works on clinical data, is fast and only requires a small amount of manual input, and so it is applicable for use during cardiac catheterization procedures.

Automatic extraction of proximal femur contours from calibrated X‐ray images using 3D statistical models: an in vitro study

Accurate extraction of bone contours from two-dimensional (2D) projective X-ray images is an important component for computer-assisted diagnosis, planning or three-dimensional (3D) reconstruction. We propose a 3D statistical model-based, fully automatic segmentation framework for extracting the proximal femur contours from calibrated X-ray images. The automatic initialization is an estimation of a Bayesian network algorithm to fit a multiple-component geometrical model to the X-ray data. The contour extraction is accomplished by a non-rigid 2D/3D registration between the statistical model and the X-ray images, in which bone contours are extracted by a graphical model-based Bayesian inference. The contour extraction algorithm was verified on both cadaver and clinical datasets, visually and quantitatively. Compared to the 'gold standard', a mean error of 1.6 mm was observed when the automatically extracted contours were used to reconstruct a patient-specific surface model. Our statistical model-based bone contour extraction approach holds the potential to facilitate the application of 2D/3D reconstruction in surgical navigation.

Wall and laser spot motion in cylindrical hohlraums

Wall and laser spot motion measurements in empty, propane-filled and plastic (CH)-lined gold coated cylindrical hohlraums were performed on the Omega laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Wall motion was measured using axial two-dimensional (2D) x-ray imaging and laser spot motion was perpendicularly observed through a thinned wall using streaked hard x-ray imaging. Experimental results and 2D hydrodynamic simulations show that while empty targets exhibit on-axis plasma collision, CH-lined and propane-filled targets inhibit wall expansion, corroborated with perpendicular streaked imaging showing a slower motion of laser spots.

Development of position sensitive radiation detectors using gas electron multipliers

Gas electron multipliers (GEM) were introduced to develop a radiation detector which is applicable to medical imaging or luggage inspection systems at the airport or harbor. Two GEM foils were used in the amplifier, and an Ar/CO 2 mixed gas was inserted into the chamber at a mixing ratio of Ar:CO 2=80:20. A two-dimensional X-ray image was taken with a 64-channel GEM detector from an Fe-55 radiation source. We also constructed a 256-channel GEM detector in which 4 charge sensitive preamplifiers were used in a daisy chain. With linear array type readout electrodes, we were able to realize a position sensitive radiation detector.

Dynamic measures of regional lung air volume using phase contrast x-ray imaging

Phase contrast x-ray imaging can provide detailed images of lung morphology with sufficient spatial resolution to observe the terminal airways (alveoli). We demonstrate that quantitative functional and anatomical imaging of lung ventilation can be achieved in vivo using two-dimensional phase contrast x-ray images with high contrast and spatial resolution (<100 µm) in near real time. Changes in lung air volume as small as 25 µL were calculated from the images of term and preterm rabbit pup lungs (n = 28) using a single-image phase retrieval algorithm. Comparisons with plethysmography and computed tomography showed that the technique provided an accurate and robust method of measuring total lung air volumes. Furthermore, regional ventilation was measured by partitioning the phase contrast images, which revealed differences in aeration for different ventilation strategies.

Monochromatic x-ray sampling streak imager for fast-ignitor plasma observation

Ultrafast two-dimensional (2D) x-ray imaging is required to investigate the dynamics of fast-heated core plasma in inertial confinement fusion research. A novel x-ray imager, consisting of two toroidally bent Bragg crystals and an ultrafast 2D x-ray imaging camera, has been demonstrated. Sequential and 2D monochromatic x-ray images of laser-imploded core plasma were obtained with a temporal resolution of 20 ps, a spatial resolution of 31 mum, and a spectral resolution of over 200, simultaneously.

Observation of asymmetrically imploded core plasmas with a two-dimensional sampling image x-ray streak camera

A shell target with a cone for guiding the heating beam has been proposed for the fast ignition scheme. Implosion of such target is no longer symmetric because of the cone. A fast two-dimensional x-ray imaging technique, two-dimensional (2D) sampling image x-ray streak camera was applied for the first time to observation of the dynamics of implosion and core plasma. X-ray emission image of the plasma was sampled with two-dimensionally distributed image sampling points, streaked with the tube, and the recorded signals were reconstructed as sequential 2D frame images. Shape and movement of the core plasma were clearly observed.