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... stenosis. It looks from the transesophageal and the 3-D echo that most of the problem is really ... posterior leaflet, which you can see on the 3-D echo image is a major source. The anterior ...

UK PubMed Central (United Kingdom)

BackgroundMany three-dimensional (3D) images are routinely collected in biomedical research and a number of digital atlases with associated anatomical and other information have...Full Text Available

Medline Plus

... acquired, which we then volumetrically fuse with the 3D image set from the MR. And by doing ...

International Nuclear Information System (INIS)

The application of 3D rotational angiography marks a breakthrough in endovascular treatment of aneurysmas of the brain. 3D images are produced based on image series obtained by rotational angiography, so that the anatomic details of interest can be visualized from any requested angle. (orig./CB)

UK PubMed Central (United Kingdom)

Motivation: Cell tracking is an important method to quantitatively analyze time-lapse microscopy data. While numerous methods and tools exist for tracking cells in 2D time-lapse images,...Full Text Available

UK PubMed Central (United Kingdom)

ObjectiveCompare occlusal contacts calculated from 3D virtual models created from clinical records to contacts identified clinically using shimstock and transillumination.Full Text Available

International Nuclear Information System (INIS)

Objective: To investigate the value ofMSCT in observing the direct findings of hilar cholangiocarcinoma1Methods Multislice helical CT studies were performed on the upper abdomen in 19 consecutive patientswith painless jaundice1 Precontrast and dynamic contrast enhanced (25 s phase and 60 s phase) scanswere conducted, and 3D imageswere reconstructed using enhanced raw data in 15 cases1 The direct CT findings of hilar cholangiocarcinoma were studied by three radiologists respectively in a 32scale strategy1 The morphological features and extension of bile duct involvement by hilar cholangiocarcinoma were analyzed1 All the 19 caseswere pathologically p roved as hilar cholangiocarcinoma by surgery (15 cases) and ERCP ( 4 cases) 1 Results The direct findings and extension of hilar cholangiocarcinoma could be demonstrated in 14 out of 15 3D reconstruction images, 8 out of 19 in 25 s phase, ...

International Nuclear Information System (INIS)

The authors have been developing a 3D brain CT image display system for planning of craniofacial operations. This system helps doctors plan craniofacial operations on a graphic display (GD) terminal by rendering 3D images reconstructed from a set of slices. The authors reveal how the system generates 3D shapes of organs from given CT images and how it modifies or transforms the obtained shapes according to the user's request. The system functions now available are extraction and display of the skull and the skin, measurement of the distance between two points on the skull given through the GD terminal, and generating and eliminating a polygonal region arbitrarily given on the skull as an operative region. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

Following the conventional X-ray diagnosis of the skull and upper cervical spine, CT proved to be the primary diagnostic method after a skull and brain injury: For all 4 cases we succeeded in detecting the occipital condyle fracture and in determing its size and location by reconstructions (coronal, sagittal, 3-D). In the case of complex occompanying injuries like soft tissue hematomas (cerebral, in the spinal cord, and the soft tissue of the neck) or for the detection of brain stem contusion, MRT had significant advantages. MRT can offer a higher image quality in soft tissue, especially in the spinal cord and the brain. (orig.) [Deutsch] Im Anschluss an die konventionelle Roentgendiagnostik des Schaedels und der Halswirbelsaeule, erwies sich die Computertomographie als primaer einzusetzendes diagnostisches Verfahren, nach erlittenem Schaedel-Hirn-Trauma. In allen Faellen gelang der exakte ...

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Twenty-two out of 31 patients with chronic renal failure and secondary hyperparathyroidism who underwent parathyroidectomy before operation underwent non-invasive image diagnosis of parathyroid glands by computed tomography (CT), scintigraphy with /sup 201/TlCl and /sup 99m/TcO/sup 4 +/, and/or ultrasonography. CT visualized 39 of 45 parathyroid glands (86.7%), weighing more than 500 mg. Scintigraphy with a subtraction method using a computer performed the diagnosis in 19 of 27 glands (70.4%). Ultrasonography detected 21 of 27 glands (77.8%). Image diagnosis was also useful in the postoperative follow-up study. The non-invasive image diagnosis of parathyroid glands in patients with chronic renal failure is thus valuable for 1) definite diagnosis of secondary hyperparathyroidism, 2) localization, and 3) ...

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Evaluation and interpretation of CT colonography is based on both 2D and 3D techniques. The 2D techniques are popular mainly because the time needed for evaluation is short. The 3D techniques allow better definition than the 2D techniques, especially of polyps close to folds or at the base of a fold. The evaluation strategies generally accepted so far (primarily 2D, with 3D for problem cases, or vice versa) demand knowledge of both 2D and 3D techniques. Newer 3D visualization techniques help make it possible to acquire more complete and faster recording particularly of areas that are not easily accessible to endoscopic examination. These user-friendly developments are thus well suited to improving the detection and the security of detection of polyps. It must be remembered that ...

International Nuclear Information System (INIS)

Computed tomography allows today to reconstruct three-dimensional (eD) images fram axial scans. The authors report their experience in cranio-facial pathology achived in two Departments of Radiology (University of Trieste, Italy and University of Standford, California). 3D images have been realized using two different softwares, one of which allows to reconstruct both soft tissue and bone structures. The application in maxillo-facial traumas, cranio-facial malformations and head tumours are disscussed. 3D images turned out to be very useful for the optimal visualization and for the spatial demostration of the lesion and have potential applications in cranio-facial surgery and radiotherapy.

International Nuclear Information System (INIS)

Purpose of this work is to investigate the role of Helical CT and the usefulness of three-dimensional (3D) imaging for pre-operative planning and follow-up of reconstructive maxillofacial surgery with alloplastic material in neoplastic disease involving this region. From 1996 to 1999 eleven patients were examined with Helical CT and 3D images for planning of maxillofacial plastic and reconstructive surgery for advanced cancer of this anatomically complex region. A 3D-modulated titanium mesh (100%) or micro nets was used to rebuild the anterior surface of maxillary bone and the orbital floor. The mesh was cut to the appropriate size and shape and curved where necessary. Within the residual sinusal cavity a siliconed filling was used surmounting an acrylic prosthesis with dental arch to rebuild the palate. A rehydrated ...

International Nuclear Information System (INIS)

The aim of this work was to develop several strategies and software-packages for the evaluation of in-vivo-data of the human brain, which were acquired with high-resolution 1H-MRSI at 1.5 and 3 T. Several studies involving phantoms, volunteers and patients were performed. Quality assurance studies were conducted in order to evaluate the reproducibility of the applied MR-techniques at both field strengths. A qualitative comparison-study between MRSI-data from a 1.5 T clinical MR-scanner and a 3 T research MR-scanner showed the advantages of the more advanced MRSI sequences and higher field strength (3 T). A study involving patients with primary brain tumours (gliomas) was performed in cooperation with the Department of Neurosurgery (University of Erlangen-Nuremberg). The methods developed in the course of this study, such as the integration of MRS-data into a stereotactic-system, the segmentation of metabolic maps and the correlation with histopathological findings represent a package ...

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Faults are being actively investigated across Japan since the Great Hanshin-Awaji Earthquake. Discussed in this report is the application of the 3D near-surface reflection seismic survey in big cities. Data from trenching and drilling is used for the geological interpretation of the surroundings of a fault, and the reflection seismic survey is used to identify the position, etc., of the fault. In this article, when the results obtained from the experimental field are examined, it is found that the conventional 2D imaging reflection survey betrays the limit of its capability when the geological structure is complicated, that the 3D reflection seismic survey, on the contrary, is capable of high-precision imaging and, when augmented by drilling, etc., becomes capable of a more detailed interpretation, and that it also contributes effectively to the improvement of ...

International Nuclear Information System (INIS)

A 65-year-old woman who was diagnosed as having psoitis by CT findings, which disclosed non-symmetrical dilation of the psoas muscle and gaseous image. Pus from the psoas muscle seen at surgery corresponded to CT findings. Preoperative CT examination was useful in the establishment of diagnosis. (Namekawa, K.).

International Nuclear Information System (INIS)

Three dimensional data of brain from the formalin-fixed fetuses were collected without isolation, by the 4.7 tesla super high magnetic field MRI and the developmental process of the cerebral parenchyma was studied by 3D images. Subjects were 13 fetal brain and MRI was performed using 3D-steady-state free precession sequence. The isolated brain is very soft and fragile and is deformed by its weight at the imaging. However 3D-MRI can be obtained without isolation, and the deformation is remarkably small. The subependymal germinal matrix layer did not be observed in 7 weeks-old fetus, appeared at 9 weeks-old and increased gradually. Then it rapidly reduced from 28 weeks-old. The volume calculated, from 3D-MRI, increased rapidly from 9 weeks-old to 23 weeks-old, and reached the ...

International Nuclear Information System (INIS)

Herein we present an impact of diagnosis by enhanced multidetector-row computed tomography and magnetic resonance imaging for extrahepatic cholangiocarcinoma (ECC). Although the diagnosis against the longitudinal stromal extension and surrounding tissue invasion of ECC by multi detector row CT (MDCT) and MRI was very strict, we could not detect any superficial mucosal spread (SMS). Furthermore, the diagnosis of lymphnode metastasis by MDCT/MRI was miserable. We believe that misdiagnosis of SMS is permissible since positive mucosal but not stromal surgical margin was not a significant factor influencing the postoperative prognosis. However, further advances in imaging diagnosis for ECC is needed. (author)

Science.gov (United States)

We develop a 3-D model to simulate the synthetic aperture radar (SAR) image formation process of an undulated vegetation canopy such as corn grown in fields with large periodic drainage reliefs. We explain how the simulated SAR image of undulated vegetation medium is obtained by the convolution of a 2-D slice of the 3-D simulated SAR system point spread function [(PSF), emulating the SAR beam modeled by a cosine modulated Gaussian], with the 2-D projection of the observed undulated vegetation canopy (modeled with scatterers randomly distributed in 3-D undulated space) followed by the extraction of each look envelope, the summation of looks, and sampling in azimuthal and range directions. Our model is useful to study the parameters involved in the formation and the analysis of SAR images of undulated ...

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To investigate the usefulness of a newly developed magnetic resonance (MR) image-guided surgical robotic system for minimally invasive laparoscopic surgery. The system consists of MR image guidance [interactive scan control (ISC) imaging, three-dimensional (3-D) navigation, and preoperative planning], an MR-compatible operating table, and an MR-compatible master-slave surgical manipulator that can enter the MR gantry. Using this system, we performed in vivo experiments with MR image-guided laparoscopic puncture on three pigs. We used a mimic tumor made of agarose gel and with a diameter of approximately 2 cm. All procedures were successfully performed. The operator only advanced the probe along the guidance device of the manipulator, which was adjusted on the basis of the preoperative plan, and punctured the target while maintaining the operative field using ...

International Nuclear Information System (INIS)

The objective of this study was to develop a method for 3D subtraction CT angiography and to optimize the visualization after semiautomatic segmentation. Ten patients with aneurysms of the abdominal aorta were examined using spiral CT. To reconstruct the vessels, as well as adjacent organs such as the liver and kidneys, one image data volume was acquired before and after injection of the contrast agent. The CT scans were obtained with a Siemens Somatom Plus 4. To improve the results of automatic segmentation, as well as visualization by maximum intensity projection (i.e. removal of bony structures), subtraction of both image volumes is necessary. However, small translation shifts disturb the subtraction process and produce artificial contours. To calculate the disparities along the three coordinate axes of two corresponding image volumes, a cepstrum filter is applied to a pair of ...

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Already, MR Imaging is superior in diagnostic imaging of joints in many cases; however, there have been recent developments, which are the subjects of this paper. With gradient-echo sequences acquired in 3D technique, it is possible to produce high-resolution images of joints in acceptable scantime, because gradient-echo sequences are less time-consuming than convential SE sequences. With the acquisition of two echoes, phase difference between water and fat protons have to be considered. 3D Imaging is capable of displaying complex pathology in a superior way, which should be useful in preoperative planning. Tissue contrast is altered by fat saturation or magnetization transfer in order to achieve better conspicuity of lesions. Although diagnostic value of some of these options is not yet clear and further clinical ...

International Nuclear Information System (INIS)

Post-mortem magnetic resonance (MR) imaging is of increasing interest not only as an alternative to autopsy but as a research tool to aid the interpretation and diagnosis of in utero MR images. The information from the post-mortem MR has allowed the development of imaging sequences applicable to in utero imaging and neonatal imaging. It has established brain development during gestation and has provided data on this to which in utero MR can be compared. The detail available from the post-mortem images is such that brain development can be studied in a non-invasive manner, a permanent record on the normal and abnormal areas is available and a greater understanding of developmental abnormalities is possible.

Science.gov (United States)

The purpose of this study was to use high-resolution magnetic resonance (MR) imaging combined with image analysis to investigate the three-dimensional (3D) trabecular structure, anisotropy, and connectivity of human vertebral, femoral, and calcaneal specimens. The goal was to determine whether: (a) MR-derived measures depict known skeletal-site-specific differences in architecture and orientation of trabeculae; (b) 3D architectural parameters combined with bone mineral density (BMD) improve the prediction of the elastic modulus using a fabric tensor formulation; (c) MR-derived 3D architectural parameters combined with BMD improve the prediction of strength using a multiple regression model, and whether these results corresponded to the results obtained using higher resolution depictions of trabecular architecture. A ...

Science.gov (United States)

A novel phantom has been developed to measure the modulation transfer function (MTF) in 3D for x-ray computed tomography. The phantom consists of three tungsten wires, positioned nearly orthogonal to each other. Simultaneous measurements of the MTF are taken at various locations along the three orthogonal reconstructed planes. Our computed mammotomography (CmT) system uses a Varian Paxscan 2520 digital x-ray detector which can be positioned anywhere in ~2pi steradian band and can have arbitrary trajectories. With a half-cone beam geometry and with the phantom positioned near the center of rotation, projection images are acquired over 360 degrees. Various 3D orbits are evaluated including vertical axis of rotation and saddle. Reconstructions were performed using an iterative ordered-subsets transmission algorithm on rebinned projection images, using various ...

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Problems and solutions in the diagnosis and operative treatment were clarified by retrospective evaluation of cases of intramedullary tumor in which MRI and surgery had been performed. The subjects were 16 patients (21-75 years old, mean age: 45 years) whose tumor was surgically removed between 1991 and 1998. MRI was performed preoperatively, and T1-weighted images, T2-weighted images, and enhanced images were obtained. Angiography was also performed in some cases. The histological diagnosis based on the MRI findings before surgery were compared with the pathological diagnosis after the operation. In 9/16 cases (56%), the preoperative histological diagnosis based on the MR images was the same as the pathological diagnosis after the operation. In 8 of the 11 cases (73%) whose ...

International Nuclear Information System (INIS)

Energy-filtered X-ray photoemission electron microscopy (EXPEEM) is a microscopy technique which has the potential to provide surface chemical mapping during surface chemical processes on the nanometer scale. We studied the possibilities of EXPEEM using a Wien filter type energy analyzer in the high energy X-ray region above 1000 eV. We have successfully observed the EXPEEM images of Au islands on a Ta sheet using Au 3d_5_/_2 and Ta 3d_5_/_2 photoelectron peaks which were excited by 2380 eV X-rays emitted from an undulator (BL2A) at Photon Factory. Our recent efforts to improve the sensitivity of the Wien filter energy analyzer will also be discussed.

British Library Electronic Table of Contents (United Kingdom)

Purpose To evaluate the methods of applicator reconstruction in 3D MR-based planning for brachytherapy of cervical cancer, and to investigate applicator shifts and changes in DVH parameters during PDR treatment. Methods For each application MR scans with applicator in situ were made: three T2-weighted (4.5mm slices) Turbo Spin Echo (TSE) scans and a balanced Steady State Free Precession scan (1.5mm). Three observers tested two applicator reconstruction methods: (A) directly on the bSSFP scan and (B) on a resampled combination of the three T2-weighted scans. For 10 patients MR imaging was repeated on the second day of each PDR fraction to determine applicator shifts and changes in DVH parameters. Results For both applicator reconstruction methods the interobserver variation for the DVH para...

UK PubMed Central (United Kingdom)

Arriving at a firm diagnosis of neurosarcoidosis continues to pose serious problems, particularly when evidence of granulomatous disease outside the nervous system is lacking. The commonest mode of...Full Text Available

UK PubMed Central (United Kingdom)

Assessment of subtle changes in the primary macromolecular components of cartilage, proteoglycan (PG) and collagen, is critical for the diagnosis of early stages of osteoarthritis (OA), but...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Sixty-six cases of histologically proven hepatocellular carcinomas (HCC) were studied by MRI. Detectability was better by MRI than by CT, especially in the tumor under 2 cm in diameter. The capsule was detected in all cases of HCC over 3 cm in diameter. The capsule was able to be diagnosed only by dynamic MRI study in some cases. High intensity on the T1-weighted image and iso or low intensity on the T2-weighted image suggested that the nodule was adenomatous hyperplasi (AH) or well differentiated HCC. MRI is concluded to be an essential modality in the diagnosis of HCC. (author).

British Library Electronic Table of Contents (United Kingdom)

Abstract Neurodegenerative and neurometabolic disorders may cause significant morbidity and mortality in children. Imaging is important in early diagnosis of metabolic disorders and in determining the extent of brain injury. Especially after the development of new techniques such as diffusion-weighted magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS), neuroimaging plays more important role in the diagnosis and management of these disorders. In these disorders, usually a mutation causes a clinically significant block in one or more metabolic pathways. This blockage usually results in either a deficiency of the product or in an accumulation of substrate with damage induced by either storage or toxicity. The presenting symptoms are usually nonspecific. In some of the ...

International Nuclear Information System (INIS)

As part of the evolution of computer technology, Fuji Computed Radiography (FCR) has been developed as a new system for radiographical diagnosis. In this system, the X-ray energy is stored on the imaging plate and then converted into digital signals utilizing scanning laser-stimulated luminence. After proper image processing, it offers much more improved information for diagnosis than the conventional film system does. Since April, 1986, we have principally used FCR (System 101) for neurosurgical practice. In this article, we present our recent experience and evaluate its usefulness. (author).

International Nuclear Information System (INIS)

The use of magnetic resonance imaging for diagnosis and the preoperative staging of renal cell carconoma was evaluated in 79 patients with 88 tumors. Gradient-echo and spin-echo images before and after intravenous administration of Gadolinium DTPA were compared with the results of computed tomography (CT) and histologic staging. The two imaging techniques had comparable results: T-stage was predicted correctly with CT in 78%.4% and with MRI in 84.0% of the cases, while the N-stage was accurately assessed in 81.8% and 79.5%, respectively. MRI had some advantages in diagnosing perirental tumor spread and in excluding an infiltration beyond Gerota's fascia. Therefore, MRI is a true alternative to CT for staging large renal cell carcinomas and especially for patients with contraindications for iodinated contrast agents. (orig.).

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Purpose: The aim of this study was to evaluate the accuracy of MRI in the measurement of cartilage thickness of the ankle joint in comparison to pathologic and histologic specimens. Patients and methods: The ankle joints of four fresh cadaver feet were imaged on a 1.5 T MR-unit in the coronal plane. Standard T{sub 1}-weighted spin echo (SE) and a T{sub 1}-weighted 3D-GE (FLASH-3D) sequence with fat saturation were applied. Following MR imaging, the talus was explanted and cut parallel to the MR images for macroscopic evaluation and histologic specimens were prepared. MRI measurements of the cartilage thickness of the talus were carried out in two ways: Without and with consideration of a transition zone of intermediate signal intensity between hyperintense cartilage and hypointense cortical bone. The data were compared with the anatomic ...

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This contribution provides an overview and imparts basic knowledge on pertinent technical developments in magnetic resonance imaging (MRI) of the liver: 3D sequences, respiratory triggering, parallel imaging, and 3 Tesla (3T). 3D sequences can be used as T1-weighted (T1w) sequences for analyzing dynamics of contrast enhancement or as T2w sequences for MR cholangiography. Consistent improvements in respiratory triggering make it possible to obtain good image quality on T2w scans even in patients unable to hold their breath. Parallel imaging as a universal technique to accelerate image acquisition is particularly appropriate for MRI of the liver, and it has been shown that the reduced acquisition time is not achieved at the expense of image quality. Further progress in MRI of the ...

International Nuclear Information System (INIS)

In spite of the improved imaging techniques currently available, mortality for pancreatic cancer is still high, and pancreatics is often diagnosed only in its advanced stages. The authors investigated the value of different imaging techniques - i.e., US, CT, and ERCP - for an early diagnosis, when a more effective (curative?) treatment can be suggested. Fifty-six cases of pancreatic cancer and 36 cases of chronic pancreatitis were evaluated. The results indicate that ERCP, with the help of statistical methods, is superior to US and CT not only in evaluating early neoplastic or inflammatory lesions, but also for their differential diagnosis. In the letter case, ERCP can sometimes be used as a valid alternative to fine-needle aspiration biopsy.

International Nuclear Information System (INIS)

Because of the superior tissue contrast, high spatial resolution, and multiplanar capabilities, fetal magnetic resonance imaging (MRI) can depict fetal brain pathologies with high accuracy. Pathological fetal brain development may result from malformations or acquired conditions. Differentiation of these etiologies is important with respect to managing the actual pregnancy or counseling future pregnancies. As a widened ventricular system is a common hallmark of both maldevelopment and acquired conditions, it may cause problems in the differential diagnosis. Fetal MRI can provide detailed morphological information, which allows refinement of the diagnosis of ventricular enlargement in a large number of cases. Systematic work-up of morphological details that may be recognized on MR images provides an approach for achieving a correct diagnosis in cases of ventricle enlargement. (orig.)

International Nuclear Information System (INIS)

Ewing's sarcoma and Triton's tumor are two uncommon bone tumors of the skull that have nonspecific clinical and imaging features. However, imaging methods are important in the detection of the lesions during the diagnostic investigation in order to evaluate the extent of the bone lesions, involvement of the soft tissues and brain, and to determine the presence of local recurrence and metastases. The confirmatory diagnosis relies on histological studies and immunohistochemistry. The authors report two cases of patients with these tumors and present the radiological findings. (author)

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The introduction of CT scan and, more recently, magnetic resonance imaging, has radically changed the diagnostic approach to tumors developed in the internal auditory canal and cerebellopontine angle. CT scan with intravenous injection visualizes tumors lying in the cerebellopontine angle. Magnetic resonance imaging, especially using gadolinium, is a very accurate means for diagnosing tumors of both the auditory canal and cerebellopontine angle.

CERN Document Server

The vertical profiles of disc galaxies are built by the material trapped around stable periodic orbits, which form their "skeletons". According to this, the knowledge of the stability of the main families of periodic orbits in appropriate 3D models, can predict possible morphologies for edge-on disc galaxies. In a pilot survey we compare the orbital structures which lead to the appearance of "peanuts" and "X"-like features with the edge-on profiles of three disc galaxies (IC 2531, NGC 4013 and UGC 2048). The subtraction from the images of a model representing the axisymmetric component of the galaxies reveals the contribution of the non-axisymmetric terms. We find a direct correspondence between the orbital profiles of 3D bars in models and the observed main morphological features of the residuals. We also apply a simple unsharp masking technique in order to study the sharpest ...

International Nuclear Information System (INIS)

Conformal radiation therapy represents a considerable and attractive challenge in oncology. Its aim is mainly to improve local control by increasing the dose with an acceptable rate of complications. This work overviews the world literature on this subject. The technical and theoretical requirements are highlighted. These requirements include a precise definition of the target volume by digital imaging (essentially CT scan), but also clear view of the target volume and the organs at risk, a specific collimation of the beam, 3-D dose calculations, optimization procedures, and a rigid immobilization of the patient with verification of his position. Moreover, the clinical applications of conformal radiation therapy are reviewed and discussed. (authors). 80 refs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

Magnetic resonance (MR) imaging and histopathology were used to diagnose an articular process synovial myxoma in a dog. On MR images, the tumor was characterized by distortion of the left L1-L2 articular process, widening of the articular process joint, and the presence of a mass contiguous with the synovium of the articular process that displaced the spinal cord. The tumor was T2-hyperintense, T1-hypointense, relative to muscle, and had mild contrast enhancement. The MR features of articular process synovial myxoma may be distinct from other diseases of the articular process joint.

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In our evaluation we utilized the Asahi Mark-J NMR-CT system, with a resistive vertical quadrupolar electromagnet (0.1 Tesla) and a proton resonance frequency of 4.5 MHz. Our main imaging methods are the inversion-recovery or IR, saturation-recovery, or SR, and calculated T/sub 1/. Difference, or D images, constructed by subtracting the data of the IR signal from that of the SR signal, have also been obtained in some cases. The system allows averaging of raw data. Hybrid images were constructed from two or more images to obtain clear definition of areas of interest. By using the hybrid image, several tissues of different relaxation times can be shown in the same image. Application in our study of the newly developed hybrid image indicates its importance in the detection and diagnosis of lesion, especially the detection ...

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The NIS-6 group at Los Alamos National Laboratory pioneered the development of Tomographic Gamma Scanning and continue to improve its utility in real measurement situations. Building on this experience we report the development of a state of the art TGS system suitable for industrial applications. The image reconstruction and visualization software has been integrated into the familiar Canberra NDA2000 software suite which also handles all other aspects of the data acquisition and management. In this paper we describe the salient design and performance parameters of the system. The application of gamma-ray tomography to safeguards for improved assay accuracy and knowledge confirmation is discussed. In particular we compare and contrast the relative merits of this TGS and a traditional Segmented Gamma Scanner and illustrate how the 3-D visualization of the TGS image can provide valuable additional ...

International Nuclear Information System (INIS)

A computer controlled digital system, Fuji Computed Radiography (FCR) is capable of providing more stable output image than conventional screen/film system. So FCR would be an ideal system for the detection of pneumoconiosis due to the constant high quality of the output films. We tried to find the optimum image processing to compensate the small size (1/2 in length of a full-size radiograph) of the output image of digital radiography. The best result for FCR was given with gamma 0.85 and 0.30 enhancement of response at spatial frequency of 0.085 cycle/mm. On the other hand, the digitally processed FCR size ILO standard films, the characteristics of which is different from FCR output films, proved to be most preferable when the image processing is made with gamma 0.85 and 0.25 enhancement at spacial frequency of 0.17 cycle/mm. If the above mentioned image processings are adopted, ...

Energy Technology Data Exchange (ETDEWEB)

A single exposure energy subtraction technique with a metal filter and an imaging plate for the Fuji Computed Radiography (FCR) system was developed for dual-energy subtraction radiography (DES) of the chest. By the use of this technique, 206 patients with suspected lung cancer were scanned in the clinical settings. The subtracted images in 200 patients, excluding six with poor image quality, were examined. Soft-tissue images (bone cancelled images) were useful in visualizing abnormality of the airway and nodules lying under the ribs; and bone images (soft-tissue cancelled images) in detecting rib metastases and the presence or absence of calcification in nodules. Additional information was acquired in 21 % (42/200). A single exposure is capable of neglecting motion artifacts. In addition, this technique may be of value in DES, which is ...

British Library Electronic Table of Contents (United Kingdom)

Objective To investigate value of magnetic resonance cholangiopancreatography (MRCP) using oral diluted gadolinium (Gd)-diethylenetriamine penta-acetic acid (DTPA) as negative contrast materials in diagnosis of juxtapapillary duodenal diverticulum with atypical imaging features. Methods Nineteen patients with juxtapapillary duodenal diverticula of which imaging findings were atypical underwent MRCP using oral diluted Gd-DTPA as negative contrast materials after conventional MRCP without any oral contrast materials. Results Twenty diverticula were revealed in the 19 patients. At conventional MRCP, the diverticula appeared as rounded lesion with high signal intensity. After oral administration of diluted Gd-DTPA, they disappeared at MRCP. These entities were diagnosed as duodenal diverticula...

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Objective. To compare turbo inversion recovery magnitude (TIRM) with standard T1-weighted (T1-W) and T2-weighted (T2-W) MR sequences in the very early detection of acute osteomyelitis in children. Materials and methods. In 15 children with osteomyelitis, 15 sets of T1-W spin-echo (SE) (TR/TE, 400-640/12-17), T2-W turbo spin-echo (TSE) (TR/TE/ETL, 3290-4465/112-120/11), and TIRM (TR/TE/TI, 4000-6120/60/160) images were acquired with a 1.0-T magnet. Contrast-to-noise (C/N) ratios and percentage of signal between lesion and normal bone marrow were analysed with a computer-assisted image analysing system in a region of interest (ROI). Results. In 13 of 15 patients, the absolute signal enhancement in a ROI on the TIRM images was better than on the T1-W SE and T2-W TSE images and in 14 of 15 cases, C/N ratios were also better on the TIRM images than on the other sequences. In the other ...

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The 3-dimensional (3D) extension C5G7 MOX benchmark problems were solved by CHAPLET-3D code which is based on the idea of dynamic linkage of the multi-plane method of characteristics solutions. The benchmark results are quite accurate in comparison with the reference solutions, independently of the axial solver incorporated in the CHAPLET-3D code. (author)

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The book is intended as a source of information for general practioners and for medical students doing their practical training. Efficient application of imaging methods is explained with great emphasis on practical aspects, concentrating on typical tasks to be solved for adult patients with internal disease or surgical problems. The material is arranged by various organic systems of the body. Graded diagnostics for a stepwise approach to the final diagnosis is the concept described, and is shown to be of advantage to the patient and in terms of cost and time.

International Nuclear Information System (INIS)

Leukodystrophies are inherited white matter diseases due to abnormalities occurring in myelin synthesis and/or maintenance. The most common types of these rare childhood conditions are represented by adrenoleukodystrophy, metachromatic leukodystrophy, Canavan's, Alexander's, Krabbe's, and Pelizaeus-Merzbacher's diseases. Most of them are lethal during childhood, with the exception of the adrenoleukodystrophy-adrenomyeloneuropathy complex, which sometimes, during its early phases, may be cured with a dietary therapy. The aims of this paper are: 1) the description of inheritance factors, pathogenesis, pathological and clinical findings of each of the most frequent childhood leukodystrophies; 2) the description of the most common patterns of these conditions on CT and MR imaging; 3) the evaluation of the diagnostic capabilities of these two imaging techniques and the comparison of their results. Finally, some of the therapies suggested for the ...

International Nuclear Information System (INIS)

Purpose: The aim of this study was to demonstrate the typical appearance of ganglioneuromas in computer-assisted tomography (CT), and magnetic resonance imaging (MRI). Material and methods: Retrospective analysis of diagnostic imaging (9 CT, 6 MRI) in 9 children aged 3 to 15 years with the histological diagnosis of ganglioneuroma. Results: The tomographies showed large (max. 13.4 cm in diameter) round or oval tumors with sharp delineation. The sites of the tumors were the retroperitoneum (5), the mediastinum (3), and the adrenal gland (1). Intraspinal tumor involvement occurred in 4 cases. On comparing CT with MRI, MRI was more accurate in defining the intraspinal involvement. The ganglioneuromas were of hypodense appearance in the native CT scan and showed moderate enhancement upon administration of contrast media. In five patients tumor calcifications with a disseminated sprinkled pattern were seen in CT. In MRI ...

International Nuclear Information System (INIS)

A small cholangiocarcinoma was detected at autopsy in a patient with thorotrastosis who died from the rupture of esophageal varices at the esophagogastric junction. Prior to the advent of recent diagnostic imaging technique, a correct antemortem diagnosis could only be obtained from tumor markers. However, the tendency for the opacity of the liver to decrease slowly with time and develop uneven trabeculation suggests that small tumors may be difficult to detect against such a non-homogeneous background. (author).

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We retrospectively studied the computed tomography scans of the orbit in 75 patients in order to identify the presence of incidental calcifications (scleral and trochlear apparatus calcifications.). These imaging findings should integrate the vast list of differential diagnosis of orbital calcifications, as they may help radiologists to distinguish these calcifications from orbital foreign bodies. (author)

International Nuclear Information System (INIS)

Intravenous digital subtraction angiography using Fuji computed radiography system (FCR-DSA) was used to evaluate 57 preoperative patients with clinical manifestations of peripheral vascular disease of lower extremity. With its high contrast resolution and good special resolution, image of FCR-DSA could offer optimal information of vascular abnormality in lower extremity distal to midfoot for the diagnosis and the choice of management. (orig.).

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Conventional Radiography, Fuji Computed Radiography (FCR) hardcopy and CRT images were evaluated about the detectability of pulmonary nodule using the chest phantom. Conventional and digitized chest radiographs (FCR) were used, including 45 normal cases and 45 abnormal cases with a variety pulmonary nodule. Observer performance tests were conducted to compare the effects on diagnostic accuracy of Conventional Radiography, FCR hardcopy and CRT images, and diagnostic accuracy was determined with receiver operating characteristic (ROC) analysis. ROC study was performed in which six radiologists were asked to locate nodule on three modalities. Two CRT monitors were used to observed CRT images. The left side CRT monitor was divided into two parts and displayed two images which were done as same image processing as FCR hardcopy. The right side CRT monitor was divided into four parts and ...

Medline Plus

... see and electrophysiological study and catheter ablation with 3D mapping. During the procedure, doctors look at the ... perform a electrophysiology study with ablation, using our 3D mapping system. Keep in mind, that during the ...

International Nuclear Information System (INIS)

Background and purpose: stereotactic radiosurgery (SRS) and also fractionated stereotactic radiotherapy (SRT) offer high local control (LC) rates (> 90%). This study aimed to evaluate three-dimensional (3-D) tumor volume (TV) shrinkage and to assess quality of life (QoL) after SRS/SRT. Patients and methods: from 1999 to 2005, 35/74 patients were treated with SRS, and 39/74 with SRT. Median age was 60 years. Treatment was delivered by a linear accelerator. Median single dose was 13 Gy (SRS) or 54 Gy (SRT). Patients were followed up ? 12 months after SRS/SRT. LC and toxicity were evaluated by clinical examinations and magnetic resonance imaging. 3-D TV shrinkage was evaluated with the planning system. QoL was assessed using the questionnaire Short Form-36. Results: Median follow-up was 50/36 months (SRS/SRT). Actuarial 5-year freedom from progression/overall survival was 88.1%/100% ...

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This paper describes a new time-resolved three-dimensional, three-component (3D-3C) measurement technique called wall-PIV. It was developed to assess near wall flow fields and shear rates near non-planar surfaces. The method is based on light absorption according to Beer-Lambert's law. The fluid containing a molecular dye and seeded with buoyant particles is illuminated by a monochromatic, diffuse light. Due to the dye, the depth of view is limited to the near wall layer. The three-dimensional particle positions can be reconstructed by the intensities of the particle's projection on an image sensor. The flow estimation is performed by a new algorithm, based on learned particle trajectories. Possible sources of measurement errors related to the wall-PIV technique are analyzed. The accuracy analysis was based on single particle experiments and a three-dimensional artificial data set simulating a rotating ...

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A new direction for the national laboratories is to assist US business with research and development, primarily through cooperative research and development agreements (CRADAs). Technology transfer to the private sector has been very successful as over 200 CRADAs are in place at Sandia. Because of these cooperative efforts, technology has evolved into some new areas not commonly associated with the former mission of the national laboratories. An example of this is the analysis of fabric structures. Explicit analyses and expertise in constructing parachutes led to the development of a next generation automobile airbag; which led to the construction, testing, and analysis of the Jet Propulsion Laboratory Mars Environmental Survey Lander; and finally led to the development of CAD based custom garment designs using 3D scanned images of the human body. The structural analysis of these fabric structures is described as well as a ...

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MRI, ultrasonography and angiography were performed on 24 cases with small renal cell carcinoma, and data were compared with pathological architecture type. An average diameter of cancer was 20.8 mm (10-30 mm). Each tumor was pathologically classified into four architecture types: alveolar type (15 cases), papillary type (5 cases), tubular type (3 cases) and cystic type (1 case). In comparison with renal cortex alveolar type renal cell carcinoma showed equal or low signal in T1-weighted images and equal or high signal in T2-weighted images. Papillary and tubular types showed high signal in T1-weighted images, and low signal in T2-weighted images. In alveolar type, many cases showed equal echo in ultrasonography and hypervascularity in angiography, and in papillary and tubular types, many cases showed high echo and hypovascularity. There were many cases with papillary type small cell carcinoma which ...

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To determine clinical predictors and accuracy of {sup 123}I-FP-CIT SPECT imaging in the differentiation of drug-induced parkinsonism (DIP) and Parkinson's disease (PD). Several clinical features and {sup 123}I-FP-CIT SPECT images in 32 patients with DIP, 25 patients with PD unmasked by antidopaminergic drugs (PDu) and 22 patients with PD without a previous history of antidopaminergic treatment (PDc) were retrospectively evaluated. DIP and PD shared all clinical features except symmetry of parkinsonian signs which was more frequently observed in patients with DIP (46.9%) than in patients with PDu (16.0%, p<0.05) or PDc (4.5%, p<0.01). Qualitatively {sup 123}I-FP-CIT SPECT images were normal in 29 patients with DIP (90.6%) and abnormal in all patients with PD, and this imaging technique showed high levels of accuracy. DIP and PD are difficult to differentiate based on clinical ...

International Nuclear Information System (INIS)

Ewing's sarcoma is a malignant bone tumor that can occur anywhere in the body, but it is most commonly observed in the long bones of the arms and legs, the pelvis and in the chest. The predominant sites of metastasis include the lung (38%), bone (including the spine; 31%), and the bone marrow (11%). Metastasis of Ewing's sarcoma to the central nervous system (CNS) is relatively rare, and most of the previous reports have demonstrated involvement of the bony calvarium or brain parenchyma. We describe here the imaging findings of dural metastasis of Ewing's sarcoma, and these imaging findings have not been previously reported on in the medical literature. In conclusion, dural metastasis of Ewing's sarcoma is very rare and its imaging characteristics are similar to those of a primary tumor, which mimic the findings of a schwannoma or meningioma. Despite its rarity, secondary Ewing's sarcoma may be included in the differential ...

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Osteonecrosis (ON) of the hip joint remains an unsolved therapeutical problem. Diagnosis of ON of the hip has been improved by the technical progress of imaging modalities and better understanding pathomorphology. Over a long period only plain radiographs have been available. Scintigraphy and computed tomography contributed to differential diagnosis and early detection of bone necrosis. Diagnosis in an early reversible stage is of importance. Understanding of pathophysiology, early diagnosis and therapeutical approach has been significantly improved by MR imaging. Using the ARCO system all imaging modalities and their diagnostic viability are described in the five ARCO stages. At the end a diagnostic algorithm will be proposed. (orig.) [German] Die Osteonekrose des Hueftgelenks (ON) stellt noch immer ein nicht geloestes therapeutisches ...

Science.gov (United States)

The high incidence and mortality rates of prostate cancer have stimulated research for prevention, early diagnosis and appropriate treatment. DNA ploidy status of tumour cells is an important parameter with diagnostic and prognostic significance. In the current study, DNA ploidy analysis was performed using image cytometry technique and digital image processing and analysis. Tissue samples from prostate patients were stained using the Feulgen method. Images were acquired using a digital imaging microscopy system consisting of an Olympus BX-50 microscope equipped with a color CCD camera. Segmentation of such images is not a trivial problem because of the uneven background, intensity variations within the nuclei and cell clustering. In this study specific algorithms were developed in Matlab based on the most prominent image segmentation ...

International Nuclear Information System (INIS)

339 CT und 95 MRT examinations in 210 partients were evaluated retrospectively to determine the value of CT and MRT for follow-up of head and neck tumors and for diagnosing recurrences. Semi-quantitative evaluation of tumor extent during and after radiotherapy showed advantages for MRT since changes induced by treatment, particularly oedema, produced less contrast loss in the images. CT had a sensitivity of 81% for the recognition of recurrences; this was 92% for MRT. Specificity for CT was 76% and for MRT 86%. Concerning the reliability of individual diagnostic criteria, space occupying lesions were the most valuable in CT diagnosis. For MRT, space occupying lesions and infiltration into neighbouring structures were of equal value. Because of differences in the nature of the signals, MRT proved better than CT in characterising recurrent masses and this improved the differentiation between scarring and local tumour recurrence. (orig.).

International Nuclear Information System (INIS)

Fuji Computed Radiography (FCR) is a new system of digital radiography that is based on the latest computer technologies. We applied this FCR system to the X-ray diagnosis of the laryngeal disease. Twenty patients with various laryngeal diseases were evaluated by both FCR frontal tomography and conventional screen-film frontal tomography under the same exposure condition. Both tomograms were then compared on the subject of the clarity of delineation of laryngeal structures. As the result, FCR tomograms revealed the feature of the laryngeal lumen and cartilages more clearly than conventional tomograms. In addition, energy subtraction method, which is one of FCR image processing systems, was presented as a new technical procedure to extinguish cervical spine shadows in plain anteroposterior laryngeal X-photograph. We stress that FCR system is the suitable procedure for X-ray analysis of laryngeal diseases, especially in the region related with ...

UK PubMed Central (United Kingdom)

A diagnosis of dementia is devastating at any age but diagnosis in younger patients presents a particular challenge. The differential diagnosis is broad as late presentation of metabolic disease...Full Text Available

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The main objective of this dissertation is to build a numerical 3D geological model of a turbidite reservoir using well and seismic data. For the, the first step was to elaborate a depositional model using a high-resolution genetic stratigraphy approach. Simultaneously, the stratigraphic inversion over the seismic data resulted in an optimal acoustic impedance model. Both models, were used to build, by geostatistical methods, a 3-D geological model, which represents the spatial distribution of the reservoir facies. The studied case is the late Cretaceous Namorado turbidite system in the Campos basin, which is the reservoir of the Namorado oil field, located 80 km from the Brazilian coast, under a bathymetry between 110 and 250 m. The reservoir is a turbidite succession with 90 to 180 m thickness. It is composed by sand-supported conglomerates, matrix-supported conglomerate, massive sandstones, shales, ...

International Science & Technology Center (ISTC)

Photochromes for New Generation of Highly Efficient Computers with Three Dimensional (3D) Optical Memory

Norwegian Open Research Archives (NORA)

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No abstract prepared.

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Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The main novelty of our approach is in the use of the volumetric graph to ensure consistency from symbolic representations obtained from individual slices. In this fashion, the system allows errors to be made at the slice level, yet removes them when the ...

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Both the increased complexity of integrated circuits, resulting in six or more levels of integration, and the increasing use of flip-chip packaging have driven the development of integrated circuit (IC) failure analysis tools that can be applied to the backside of the chip. Among these new approaches are focused ion beam (FIB) tools and processes for performing chip edits/repairs from the die backside. This paper describes the use of backside FIB for a failure analysis application rather than for chip repair. Specifically, they used FIB technology to prepare an IC for inspection of voided metal interconnects (lines) and vias. Conventional FIB milling was combined with a super-enhanced gas assisted milling process that uses XeF{sub 2} for rapid removal of large volumes of bulk silicon. This combined approach allowed removal of the TiW underlayer from a large number of Ml lines simultaneously, enabling rapid localization and plan view imaging of voids in lines and ...

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Uterus didelphys with obstructed hemivagina and ipsilateral renal agenesis is a rare entity, sometimes referred to as Herlyn-Werner-Wunderlich syndrome (HWW). It usually presents after menarche with progressive pelvic pain, sometimes with regular menses, and a palpable mass due to hemihaematocolpos. The diagnosis is generally made only if the suspicion of this genitourinary syndrome is raised. To highlight the imaging diagnostic clues in this rare condition. We report on 11 adolescents with this condition. Sonography mostly allowed the correct diagnosis by showing uterovaginal duplication, haematocolpos or haematometrocolpos, and the absence of the ipsilateral kidney. MRI provided more detailed information regarding uterine morphology, the continuity with each vaginal channel (obstructed and nonobstructed), and the bloody nature of the contents. Early and accurate diagnosis of this syndrome is important ...

International Nuclear Information System (INIS)

Diffusion magnetic resonance imaging (MRI) has become an important tool in the radiologic diagnosis of diseases of the brain as it measures molecular motion of water that characterizes the microstructure of tissues. Its most important clinical use to date is the early detection of cerebral ischemia by revealing the ischemic injury shortly after vessel occlusion and simultaneously providing therapy-relevant information on the tissue at risk. Furthermore, diffusion MRI is diagnostically promising in other diseases of the brain and is thus increasingly becoming part of routine clinical protocols in the diagnosis of tumors, inflammation, trauma, demyelination, dysmyelination and neurodegeneration. Although abnormalities of diffusion are generally not pathognomonic, diffusion MRI affords information about tissue changes for specific disorders that complements information obtained with standard MR techniques and frequently shows ...

Energy Technology Data Exchange (ETDEWEB)

Whenever moving surfaces interact, wear particles are produced. Microscopic examination of the morphology of such wear debris is an accepted method for machine condition monitoring and fault diagnosis. Wear particle analysis has not, however, been widely accepted in industry because it is dependent on expert interpretation of particle morphology and relies on subjective assessment criteria. Consequently, the methods are time consuming and expensive and are not always consistent. The use of automated computer image analysis systems to assess the morphology of debris promises to overcome these limitations by making the methods more time and cost efficient, and also more consistent and effective. The first step required for automation of the analysis procedure is to develop objective criteria for assessing the wear particle morphology. Numerical parameters to describe the morphology have been developed and are outlined in this paper. A system ...

International Nuclear Information System (INIS)

The US study of the posterior compartment of the knee usually allows the clinical suspicion of popliteal cyst to be confirmed. Neverthless, in case of giant Baker's cysts - which are, at any rate, less frequent -US diagnosis is more difficult. CT can help determine the benign nature of the lesion, and hallow an accurate spatial evaluation. Moreover CT, when accurately performed, demonstrates the caudal or cranial cystic spread, together with its clear separation from adjacent muscular tissues. Direct coronal scans are more useful to obtain better spatial definition than reformatted images.

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We compared the characteristics on thin-section CT images with the histological structure of thirty-four surgically resected peripheral lung lesions 30 mm or less in diameter with a greater than 50% area of GGA on thin-section CT. Pathologically, focal area of GGA corresponded to alveolar replacement growth of tumor or interstitial fibrotic thickening of inflammation. It is considered that determination of the GGA in small peripheral lung lesions on thin-section CT is useful for the diagnosis of early adenocarcinomas. (author)

Science.gov (United States)

Renal arteriovenous fistula or pseudoaneurysms developing after invasive procedures are either asymptomatic or show only transient symptoms. We describe here a case of symptomatic renal artery pseudoaneurysm that presented with gross hematuria and azotemia. The pseudoaneurysm of renal artery was diagnosed by ultrasonography and abdominal magnetic resonance imaging (MRI), and it was successfully treated by percutaneous transcatheter coil embolization. A high index of suspicion is essential for the early diagnosis and treatment of delayed gross hematuria in patients with history of percutaneous nephrostomy. PMID:17180737

International Nuclear Information System (INIS)

Computed tomography (CT) of the neck and mediastinum was performed in 16 patients with renal osteodystrophy. Thirty out of 34 excised parathyroid glands weighing more than 500mg were diagnosed preoperatively (88.2%). Scintigraphy of the neck with _2_0_1TlCl and sup(99m)TcOsub(4-) was also performed in 15 patients. The introduction of subtraction method with a mini-computor in the scintigraphy has remarkably improved the visualization rate of parathyroid glands. Ultrasonic echography (US) of the neck which is able to obtain not only transverse butalso longitudinal imaging was done in 7 patients. It has about same detection rate of the glands with CT. The visualization of enlarged parathyroid glands is valuable not only for localization but also for undeniable evidence of hyperparathyroidism. Also, repeated follow-up examination can determine the effectiveness of conservative treatment. (author).

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Pregraduate medical curricula are currently undergoing a reform process that is moving away from a traditional discipline-related structure and towards problem-based integrated forms of teaching. Imaging sciences, with their inherently technical advances, are specifically influenced by the effects of paradigm shifts in medical education. The teaching of diagnostic radiology should be based on the definition of three core competencies: in vivo visualization of normal and abnormal morphology and function, diagnostic reasoning, and interventional treatment. On the basis of these goals, adequate teaching methods and e-learning tools should be implemented by focusing on case-based teaching. Teaching materials used in the fields of normal anatomy, pathology, and clinical diagnosis may help diagnostic radiology to play a central role in modern pregraduate curricula. (orig.)

International Nuclear Information System (INIS)

Twenty-six patients with late complications following femoral neck fracture were examined with both skeletal and bone marrow radionuclide scintimetry. There was no correlation between the methods with respect to the quantitative assessment of femoral head vascularity based on different uptake ratios comparing the fractured and the intact side. Skeletal scintimetry always had good image quality and permitted reliable differentation between nonunion of the fracture and late segmental collapse, in contrast to bone marrow scintimetry which gave poor image quality. Skeletal scintimetry thus seems superior to bone marrow scintimetry for assessment and differential diagnosis of late complications following femoral neck fracture. It is emphasized that the physiological mechanisms for radionuclide uptake must be taken into account when comparing scintimetric studies using different tracers. (author).

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Since April, 1985, we have, in co-operation with the Fuji Film Co., Ltd., used Fuji Computed Radiography (FCR) in the diagnosis of spinal disorders. FCR is a new computed radiographic system which uses an energy-storage phosphorus panel called an ''Imaging Plate'' as an image sensor. The ''Imaging Plate'' can be used to obtain radiographs in exactly the same way as the screen-film combination used in conventional radiography; X-rays are exposed on the ''Imaging Plate'' instead of X-ray film in the conventional fashion, and then the ''Imaging Plate'' is calculated. The processed digital data from the scans is transformed into a picture by means of digital-to-analogue conversion. The pictures are always clear and ...

Energy Technology Data Exchange (ETDEWEB)

Purpose: To evaluate the significance of preoperative localization of abnormal parathyroid glands to the surgical outcome in patients with primary hyperparathyroidism. Material and Methods: Thirty-nine patients with primary hyperparathyroidism were studied preoperatively with US (39 patients), CT (30 patients) and MR imaging (18 patients). The overall diagnostic accuracy for US was 87%, CT 66% and MR 94%. In patients with a single parathyroid adenoma US was the most cost-effective localization technique with a detection rate of 96%. CT had a lower detection rate (78%) but was of particular value for fairly large ectopic adenomas in the root of the neck. MR imaging was a good confirmatory test (93%). In patients with multiple gland disease (primary hyperplasia and multiple adenomas), no single localization study alone was sufficient. Combination of all 3 studies, however, alerted the physician to the presence of disease in more than one gland in ...

International Nuclear Information System (INIS)

To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930 during the time period of December 8-14. The coronal helicity is calculated based on the 3D nonlinear force-free magnetic fields reconstructed by the weighted optimization method of Wiegelmann, and is compared with the amount of helicity injected through the photospheric surface of the AR. The helicity injection is determined from the magnetic helicity flux density proposed by Pariat et al. using Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms. The major findings of this study are the following. (1) The time profile of the coronal helicity shows a good correlation with that of the helicity accumulation by injection through ...

International Nuclear Information System (INIS)

The implementation of a three-dimensional conformal radiotherapy facility in the radiotherapy department of the Heinrich Heine University is described. Complex radiotherapy techniques with commercially available networked systems are introduced to improve clinical work. Over 18 month we have gained clinical experience with a PHILIPS Multileaf Collimator (MLC) mounted on a SL 25 linear accelerator. For a limited period the MLC was used as a conventional blocking device. The standard MLC-shapes are controlled with a stand-alone computer system. In addition, a three-dimensional treatment planning system (3-D-TPS / TMS-Radix, Helax AB) based on convolution/superposition algorithms was recently installed. Treatment optimization is achieved using static field arrangements with complete volumetric computerized tomographic patient data for 3-D-TPS. Conformal adaptation of the 95%-isodose to the Planning Target ...

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The usefulness of helical CT early phase images optimized by the SmartPrep method for evaluation of wall invasion by colorectal cancer was investigated. Between August 1997 and September 1998, CT was performed to evaluate the primary tumor and local extension in 10 consecutive patients with colorectal cancer confirmed by barium enema- and/or colonoscopy. Early-phase images were acquired by using SmartPrep application software. This method allows the optimal scan delay time to be obtained by continuous monitoring of increases in CT values after injection of contrast medium. Sections of the surgical specimens, close to the same plane as the CT images, and of the same slice thickness, were analyzed histopathologically. All 10 cancers, regardless of size, showed strong enhancement on the early-phase images (81.4-112 HU, mean: 95.1 HU). The strongly enhanced image areas on CT ...

Energy Technology Data Exchange (ETDEWEB)

Bone images obtained by single exposure dual energy subtraction with computed radiography, a new image processing method, were evaluated for the detectability of calcification in lung nodules in both phantom and clinical studies. In the phantom study, five simulated nodules containing known and uniformly distributed amounts of calcium hydroxide were placed in a human chest phantom and images were obtained the following five techniques: (1) conventional radiography (CXR), (2) low kV conventional radiography (Low), (3) Fuji computed radiography (FCR), (4) bone images with conventional singles exposure energy subtraction (ES) and (5) bone image with fine single exposure energy subtraction (FES). The detectability of calcification in the simulated nodules was evaluated by six radiologists using ROC analysis and two-way analysis of variance. In the clinical study, ...

Science.gov (United States)

Detailed three dimensional wing kinematics and aerodynamic characteristics are experimentally presented for the free flight of a beetle, Allomyrina dichotoma, which has a pair of elytra (fore wings) and hind wings. The kinematic parameters of the wing motion, such as the wing tip trajectory, angle of attack, torsion angle, and camber deformation, are obtained from a 3D reconstruction technique that involves the use of two or three synchronized high-speed cameras to digitize various points marked on the wings. Our data show outstanding characteristics of wing deformation and flexibility in the free flight of the beetle. To find out the mechanism of aerodynamic force, the leading edge vortex (LEV) and trailing edge vortex (TEV) on both elytron and hind wing were observed by using smoke wire visualization and digital particle image velocimetry (DPIV) technique. Qualitative smoke lines in the region of the most intent vortex ...

International Nuclear Information System (INIS)

SAFT-UT technology is shown to provide significant enhancements to the inspection of materials used in US nuclear power plants. This report provides guidelines for the implementation of SAFT-UT technology and shows the results from its application. An overview of the development of SAFT-UT is provided so that the reader may become familiar with the technology. Then the basic fundamentals are presented with an extensive list of references. A comprehensive operating procedure, which is used in conjunction with the SAFT-UT field system developed by Pacific Northwest Laboratory (PNL), provides the recipe for both SAFT data acquisition and analysis. The specification for the hardware implementation is provided for the SAFT-UT system along with a description of the subsequent developments and improvements. One development of technical interest is the SAFT real time processor. Performance of the real-time processor is impressive and comparison is made of this dedicated parallel processor to a ...

Energy Technology Data Exchange (ETDEWEB)

The Girassol field is located in Angolan deep water of Block 17 and consists of large vertically stacked turbidities complexes. The reservoir extends over approximately 200 km{sup 2} and water depth ranges between 1300 and 1400 meters. In that context High Resolution 3D seismic became the most valuable tool to describe and monitor the reservoir. The field development plan took into account, through re-injection of the gas into the reservoir, Total environmental policy imposing the recycling of production gas. Monitoring of this injection was the main reason to shoot the first High Resolution 4D extremely early in the life of field. Despite the complexity of interpretation due to complex fluid situation and pressure effect, the results went way beyond expectations as the 4D images are of very high quality. Data has also been used to update and refine the reservoir flow model as well as to help deciding on the location of ...

Medline Plus

... CT angiograph for the peripheral rteries. a beautiful 3D-vision on the structures inside e chest. Okay. ... have an angled camera here. This is a 3D camera, and the surgeon has got th What ...

Medline Plus

... Exercises: Day and Night Classroom Exercises: Pinhole Focusing 3D Vision and Eye Health < Contact Lenses Monovision Playlist: ...

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... Exercises: Day and Night Classroom Exercises: Pinhole Focusing 3D Vision and Eye Health < Caring for Your Vision ...

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance imaging (MRI) has rapidly attained a major position among the examinations used in the diagnostic approach of multiple sclerosis because it is highly sensitive in demonstrating lesions. However, these lesional images may have several meanings, and there is the problem of distinguishing between oedema, which is said to reflect recent lesions, and gliosis which is thought to betray old lesions. The intrinsic MRI parameters studied (i.e. relaxation times) are unable to make this distinction, whereas it is provided by paramagnetic contrast media such as gadolinium. There is no correlation between the changes observed at MRI and the severity of the disease. Another problem is the accuracy of lesion localization, since visualization is predominantly macroscopic. This raises several questions about the demonstration of correlations between clinical signs and site of the lesion(s). At the moment, several teams of neuroradiologists ...

International Nuclear Information System (INIS)

To analyze and review the most common focal lesions of the external auditory canal (EAC), describing the computed tomography (CT) findings. The CT images of EAC were reviewed in a series of 167 patients. Abnormal findings were recorded in 13 cases. The CT images were correlated with otoscopic and/or intraoperative findings. There were four cases of osteoma (one located outside the EAC); all of which were treated surgically, as was the one case of exostosis. Six patients presented debris in EAC, coinciding with clinical evidence of external otitis. There were two cholesteatomas derived from EAC, one of them secondary to survery to treat osteoma. On patient was diagnosed as having a basal cell carcinoma of the ear, extending to EAC, but refused to undergo surgery. Five patients presented small triangular laminae of dense bone arising from the upper wall of the EAC which were defined as abnormal variants of the fusion of the temporal squamous ...

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Direct radionuclide cystography is known to be sensitive and safe in children with suspected vesical-ureteral reflux. In this study we have investigated the utility of direct radionuclide cystography in renal transplant recipients with a recent history of pyelonephritis or recurrent urinary infections. Direct radionuclide cystography is a simple test, however it requires a rigorous methodology in order to obtain images during fill-in as well as during voiding in both men and women. The images must be interpreted using a rigorous image display methodology. Twenty-eight radionuclide cystographies were performed in 17 patients. Among the 17 tests performed for the initial diagnosis of reflux , 12 were positive. Four patients with positive results and four patients with negative results were also investigated by radiologic cystography. Similar results were obtained in those patients. Nine scintigraphies ...

International Nuclear Information System (INIS)

The purpose of this paper is to demonstrate how recent experimental results of "1"5"1Eu and "5"7Fe high pressure Moessbauer studies in 4f and 3d metallic magnetic systems can contribute to a deeper understanding of the nature of local moment (4f) and itinerant (3d) magnetism in these systems. Special emphasis is given on the comparison of the experimental results with related theoretical models. (orig.).

Energy Technology Data Exchange (ETDEWEB)

3d occupation numbers of the transition elements corresponding to various types of atomic configurations are calculated by means of the linear muffin-tin orbital (LMTO) method. This data is used with the multiconfiguration Dirac-Fock (MCDF) X-ray intensity ratios to estimate the electron populations of the 3d metals in alloys.

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The treatment of bony, osteochondral, and ligamentous injuries of the tibio-talar requires precise preoperative planning by radiological investigation. This is essential to a correct understanding of the underlying pathology and will allow a proper classification of the injury, which is the basis of treatment. Conventional radiography using anteroposterior and lateral X-rays with comparative views of the noninjured side and, if necessary, rotated spot views and tomography are of high value especially in osteochondral fractures of the talus. Intraoperative control images in both planes after osteosynthesis are mandatory. For evaluation of the postoperative course and severity of arthrosis formation, the classification system of Bargon has proved its worth. In addition, tomography of the tibio-talar joint in two planes is useful especially in tibial pilon fractures, some malleolar fractures, and peripheral talar fractures. In talar fracture dislocations with ...

Energy Technology Data Exchange (ETDEWEB)

Purpose. We have tested a procedure of focal injection of the contrast medium Lipiodol as a fiducial marker for image-guided boost of the tumor in bladder cancer radiotherapy (RT). In this study, we have evaluated the feasibility and the safety of the method as well as the inter- and intra-fraction shift of the bladder tumor. Materials and methods. Five patients with muscle invasive urinary bladder cancer were included in the study. Lipiodol was injected during flexible cystoscopy into the submucosa of the bladder wall at the periphery of the tumor or the post resection tumor-bed. Cone-beam CT (CBCT) scans were acquired daily throughout the course of RT. Results. Lipiodol demarcation of the bladder tumor was feasible and safe with only a minimum of side effects related to the procedure. The Lipiodol spots were visible on CT and CBCT scans for the duration of the RT course. More than half of all the treatment fractions required a geometric shift of 5 mm or more to ...

Energy Technology Data Exchange (ETDEWEB)

Xeroradiography (XR) was retrospectively compared with a newly developed computed radiography (FCR) for diagnostic availability for breast cancer. FCR provides with the image processed by a computer. Subjects were 65 breast cancer patients for XR and 51 for FCR. Both methods were performed preoperatively. No significant difference was observed in distribution of age between the two groups but the average tumor size in XR group was larger than that in FCR group. Tumor shadow appeared in 44 of 65 xeromammograms (67.7%) and in 34 of 51 computed radiograms (66.7%). Microcalcification was detected in 27 of 65 xeromammograms (41.5%) and in 21 of 51 computed radiograms (41.2%). Consequently, diagnosis of breast cancer could be achieved in 47 of 65 patients (72.3%, established: 39, suspective: 8) through XR and in 41 of 51 (80.4%, established: 33, suspected: 8) through FCR. Thus FCR is thought to be more useful for breast cancer because it not only ...

International Nuclear Information System (INIS)

The need for noninvasive sensitive techniques for the diagnosis and follow-up of metabolic bone disease in dialysis patients has stimulated the author's interest in the efficacy of more detailed quantitative bone scintigraphy. Using hemodialysis to reduce elevated soft-tissue activity at scintigraphy, an attempt was made to assess the diagnostic sensitivity of quantitative bone scintigraphy as compared to qualitative bone scintigraphic, biochemical, radiographic and bone histologic studies. The second aim of these studies was to determine if one of the two major components of renal osteodystrophy is a major determinant for skeletal radiotracer uptake. The clinical observations on the efficacy and possible specificity of quantitative bone scintigraphy in the diagnosis and follow-up during treatment of renal osteodystrophy are presented briefly in this chapter. Thus, the use of scintigraphy for the routine detection and follow-up of renal ...

International Nuclear Information System (INIS)

MR studies of 6 patients with intracranial tuberculoma are reviewed. All patients also underwent CT scans which showed hypo- or isodense lesions with abnormal enhancement following contrast administration. MR showed lesions with prolongation of the T1 relaxation time in every case. On the T2-weighted sequences, the signal properties of the tuberculoma varied according to the stage of evolution of the lesion. Incipient tuberculomas appeared as scattered areas of hypointensity surrounded by edema. Mature tuberculomas were composed of a dark necrotic center surrounded by an isointense capsule which was, in turn, surrounded by edema. In one patient, the center of the lesion was hyperintense probably because of liquefaction and pus formation (tuberculous abscess). While both, CT and MR, were equally sensitive in visualizing the intracranial tuberculoma in every patient, MR was slightly superior in demonstrating the extent of the lesion, especially for brainstem tuberculomas. Nevertheless, ...

Science.gov (United States)

Gallstone is a common disease with a 10% prevalence in the United States and Western Europe. However, it is only symptomatic in 20-30% of patients, with biliary pain "colic" being the most common symptom. Complications of asymptomatic gallstone disease are generally rare, with an incidence of <1 %/yr. The most common complications of gallstone disease are acute cholecystitis, acute pancreatitis, ascending cholangitis, and gangrenous gallbladder. Less frequent complications include Mirizzi syndrome, cholecystocholedochal fistula, and gallstone ileus. Mirizzi syndrome and cholecystocholedochal fistula are two manifestations of the same process that starts with impaction of a gallstone in the gallbladder neck that results in obstruction of the bile duct, causing jaundice. The gallstone may erode into the bile duct, causing cholecystocholedochal fistula. Gallstone ileus refers to small bowel obstruction resulting from the impaction of one or more gallstones after they have migrated ...

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Primary malignant lymphoma of the brain is a disease of unknown etiology, which is increasing in incidence and has an unfavorable prognosis. Despite the lack of specific changes on CT or MRI in most cases, these procedures may typically facilitate the diagnosis: A focal-enhancing mass with subependymal spread on CT or MRI and hyperattenuation on nonenhanced CT are the most reliable features in the diagnosis of primary malignant lymphoma of the brain. Peritumoral edema and mass effect are usually not prominent features. On unenhanced CT scans they usually appear homogeneously isodense to mildly hyperdense relative to the gray matter. On MRI these tumors are slightly hypointense on T1-weighted images and slightly hpyerintense on PD- and T2-weighted images relative to the gray matter. On CT and MRI enhancement is usually homogeneous. Contrast-enhanced MRI, with its multiplanar capability, lack of ...

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PMID:339527

KoreaScience (Korea)

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International Nuclear Information System (INIS)

Spinal Ewing's sarcomas are rare and cause problems in differential diagnosis. The radiologic, nuclear medicine and CT findings in two children with histologically proven Ewing's sarcoma are presented and problems in differential diagnosis discussed. Biopsy should be done early. (orig.).

CERN Document Server

Tolerancing of assembly mechanisms is a major interest in the product life cycle. One can distinguish several models with growing complexity, from 1-dimensional (1D) to 3-dimensional (3D) (including form deviations), and two main tolerancing assumptions, the worst case and the statistical hypothesis. This paper presents an approach to 3D statistical tolerancing using a new acceptance criterion. Our approach is based on the 1D inertial acceptance criterion that is extended to 3D and form acceptance. The modal characterisation is used to describe the form deviation of a geometry as the combination of elementary deviations (location, orientation and form). The proposed 3D statistical tolerancing is applied on a simple mechanism with lever arm. It is also compared to the traditional worst-case tolerancing using a tolerance ...

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The prevalence of hepatic cysts is 0.1% to 0.5% based on autopsy studies, and 2.5% based on US examinations. Percutaneous therapies are a new alternative to surgery. They include simple percutaneous aspiration, catheter drainage alone, and catheter drainage with sclerotherapy. We present an 11-year-old boy admitted to hospital because of abdominal pain. A diagnosis of simple hepatic cyst was made, which was treated with aspiration and tetracycline hydrochloride solution (5%) injection into the cystic cavity. Complete regression was seen on US and MRI examination at 3 months, with total collapse and deflation of the cyst. The cyst regressed totally, leaving a hyperechoic linear scar on US examination at 1 year. On the basis of the clinical and imaging results obtained, percutaneous sclerotherapy of hepatic cysts can be recommended as the treatment of choice and as a valid alternative to laparoscopy in children. (orig.)

International Nuclear Information System (INIS)

In an extended case report, we discuss four cases with masses in the lacrimal fossa representing the most important entities in this region (lymphoma, pleomorphadenoma, inflammatory pseudotumor, and malignant epithelial tumor). The different indications for CT and MRI are explained. For the differential diagnosis of lacrimal gland lesions, the following imaging parameters are important: The shape of the lacrimal gland, the inner structure, the degree of contrast enhancement, and the surrounding bony structures. In the evaluation of the expansion of lacrimal gland lesions, CT in thin slices with multiplanar reconstructions is equal to MRI. However, the contrast-enhancement of lacrimal glands is better evaluated with MRI than with CT. The bony structures are better visualized on CT than on MRI. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Background Adrenal incidentaloma remains a diagnostic challenge. Despite well-established management guidelines, the long-term results of following these guidelines are unknown. We sought to determine how accurately these guidelines identify functioning incidentalomas and how often these guidelines result in adrenalectomy for benign tumors. Methods We catalogued adrenal incidentalomas from a retrospective review of 500 consecutive adrenalectomies at a single institution. The outcome measures studied were patient demographics, preoperative biochemical analysis, imaging characteristics, tumor size, type of operation performed, and postoperative histologic diagnosis. Results Eighty-one of the 500 adrenalectomies performed were for incidentalomas. Size was the only significant characteristic t...

International Nuclear Information System (INIS)

The purpose of this study is to evaluate the radiologic findings of the extraosseous Ewing's sarcoma. Six patients with pathologically confirmed extraosseous Ewing's sarcoma were retrospectively reviewed. Patients included two men and four women with an average age of 21.5 years (age range 9-48 years). Plain radiographs (six patients), magnetic resonance (MR) images (five patients), computed tomographic (CT) scans (three patients) and whole body scintigraphy (two patients) were reviewed and analyzed. Images were evaluated with regard to lesion location, size, margin, muscle or bone involvement and intrinsic imaging characteristics on CT and MRI. The tumors were located in the thigh (three patients), back (two patients) and upper arm (one patient). The tumors ranged in size from 2.3 cm to 7.5 cm (mean, 5.2 cm), were mainly well circumscribed and showed no evidence of calcification prior to treatment. Margins were well ...

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The aim of this study was to qualitatively and quantitatively study MR artifacts of various stents on the basis of in vitro experiments. We were particularly interested whether sequence type and orientation of the stent with respect to the static magnetic field influences the artifact. We examined 18 stents of different material (nitinol, stainless steel, cobalt alloy), different design of the stent meshes (AccuLink, OmniLink, DynaLink, Xact, Protoge, Wallstent Monorail), different diameter (5-10 mm) and different length (18-58 mm) with a turbo spin echo (TSE), a 2D-fast low angle shot (FLASH) and a 3D-FLASH sequence. The MR images were examined qualitatively with respect to possible artifacts. Furthermore we examined the MR data quantitatively: The contrast-noise-ratio (CNR) was determined both within the stent and outside (within the tube); based on these values we calculated the transparency factor P, furthermore we ...

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Qualitative technetium Tc 99m bone scintigraphy using phosphate compounds and gallium 67 scintigraphy were described as a helpful means in diagnosing necrotizing external otitis (NEO). They were, however, claimed to be nonspecific. Quantitative Tc 99m methylene diphosphonate bone scintigraphy and gallium 67 scintigraphy were performed in eight patients with NEO and in 20 patients with severe external otitis, in order to prove usefulness of scintigraphy in the diagnosis of NEO. Ratios of lesion to nonlesion for bone scintigraphy were 1.67 {plus minus} 0.16 in patients with NEO and 1.08 {plus minus} 0.09 in patients with severe external otitis, and for gallium 67 scintigraphy they were 1.35 {plus minus} 0.24 in NEO patients and 1.05 {plus minus} 0.03 in patients with severe external otitis. There was no difference in uptake between diabetic patients with severe external otitis and nondiabetic patients. The scintigraphic studies were also evaluated using a qualitative ...

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The diagnosis of dialysis-related amyloid (AB-amyloid) has been based usually on clinical and radiological criteria. Following the discovery that beta 2-microglobulin was the major protein of this amyloid, we isolated and radiolabelled uremic plasma beta 2-microglobulin. After intravenous injection, gamma-camera images of selected joint areas were obtained from 42 patients who were on regular hemodialysis therapy. Positive scans involving the shoulder, hip, knee and carpal regions were found in 13 of 14 patients treated for more than 10 years and 10 of 16 patients treated for 5 to 10 years. Patients treated for less time had negative scans. Specificity was indicated by negative scans in non-amyloid inflammatory lesions in control hemodialysis patients. Up to 48-fold tracer enrichment was detected in excised AB-amyloid containing tissue as compared to amyloid-free tissue. These findings suggest that circulating radiolabelled beta 2-microglobulin ...

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We developed a new breast surface coil for the supine position. The subjects consisted of 9 patients with breast cancer varying from 46 to 60 years of age (average: 52). The cancer image of the SPGR (CE+) method was compared with that of the FSMTC (MTC-SPGR (CE+)) method and that of the FSMTC (MTC-SPGR with fat-saturation (CE+)) method in the sagittal section after injection of Gd-DTPA (0.1 mmol/kg). Quantitative analyses were performed before and after injection of Gd-DTPA in 6 patients. Three patients were excluded from the quantitative analyses owing to the clear detection of tumors in the fat tissue. Signal intensity measurements were systematically performed in each region of interest (ROI), i.e. the cancer lesion, the surrounding mammary gland. Statistical analyses showed significant differences between the lesions using the FSMTC (MTC-SPGR (CE+)), and the FSMTC (MTC-SPGR with fat-saturation (CE+)) methods and the lesions using the SPGR (CE+) method after ...

International Nuclear Information System (INIS)

In interventional radiology (IVR) of cerebral aneurysms, it is important to understand the form and physical relationships between the cerebral aneurysm and the surrounding vessels. However, because the vessels in the head area are highly complex, it can be difficult to comprehend the structure using conventional angiography. Therefore, three-dimensional rotational angiography (3D-RA) has been used in recent years. This article discusses studies of the spatial resolution of 3D-RA. We reconstructed 3D-RA of an acrylic slit phantom (slit widths: 0.5, 0.75, 1.0, 1.5 mm) and examined spatial resolution by visual evaluation and profile curves. When the slit phantom was arranged to avoid the effect of beam hardening, the spatial resolution of 3D-RA was found to be as high as 0.75 mm. When the slit phantom was placed orthogonal ...

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In the construction work for the Unit No.5 Turbine Building at Hamaoka Nuclear Power Station, the collaboration work for the planning and the coordination of the building construction and the machinery installation was carried out utilizing three-dimensional computer aided design (3D CAD) information. It was the first time in Japan for a building constructor and a plant manufacturer to work together, exchanging 3D CAD data of the whole building and adjusting the construction schedule. It was made possible to confirm the correspondence concerning the planning of both companies from the primary stage of the project by the total process simulation and to adjust on-going work precisely by the partial process simulation.

International Nuclear Information System (INIS)

The fundamentals and the technical application methods of the imaging procedures are discussed in detail with regard to their application in medicine. The development of the X-ray contrast media has led to a better tolerance and a significant reduction of risks. Problems relating to radiation protection and radiation exposure are discussed critically. The general point gives an overview of the radiological examination methods and is meant to deepen the understanding of the special techniques and their rationally determined application. The following special part deals with diagnosing of organs in the region of the neck and the thorax. The general basis is the conventional radiological examination. The great increase in information achieved by means of the new imaging methods becomes clear if we look at the diagnostics of the soft tissue of the neck. Computerized tomography and NMR imaging open the view at the fine ...

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Objective: To determine the reproductibility of three-dimensional volume and thickness measurements of the knee joint cartilage with MRI in volunteers. Methods: The knees of 7 healthy individuals (ages 23 to 58 yrs.) were sagitally imaged with a resolution of 2x0.31x0.31 mm{sup 3}, using a fat-suppressed FLASH-3 D sequence. The knee was repositioned in between replicate acquisitions, 6 data sets being obtained in each case. After semiautomatic segmentation and three-dimensional reconstruction of the cartilage, the thickness was determined independent of the original section orientation. The coefficient of variation for repeated volume measurements and the deviations of the maximal cartilage thickness values were calculated subsequently. Results: The mean variation of the cartilage volumes of the replicate measurements was 1.4% ({+-}0.8%) in the patella, 1.7% ({+-}1.5%) in the femur, 3.0% ({+-}1.2%) in the medial tibial ...

Science.gov (United States)

... and/or hearing mechanisms. Seven papers dealt with 3D audio technology and/or its application. Eight papers presented ...

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Guidelines for the viability primer component of the version 3 workbook. The Viability page in the current version of the Excel spreadsheet for conservation ... ...

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No abstract prepared.

Science.gov (United States)

... applications related to military and intelligence area ... the technology solved yet, but the open issue still ... fields, columns; ie data source, document type ...

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The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas will be described in this paper. The pre- and postoperative imaging of the temporal bone was performed with HRCT and MRI. HRCT and MRI were performed in the axial and coronal plane. MRI was done with T2 weighted and T1 weighted sequences both before and after the intravenous application of contrast material. All imaging findings were confirmed clinically or surgically. The preoperative cholesteatoma-caused complications depicted by HRCT included bony erosions of the ossicles, scutum, facial canal in the middle ear, tympanic walls including the tegmen tympani, and of the labyrinth. The preoperative cholesteatoma-caused complications depicted by MRI included signs indicative for labyrinthitis, and brain abscess. ...

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Automatic segmentation of anatomical structures in medical images is a valuable tool for efficient computer-aided radiotherapy and surgery planning and an enabling technology for dynamic adaptive radiotherapy. This paper presents the design, algorithms and validation of new software for the automatic segmentation of CT images used for radiotherapy treatment planning. A coarse to fine approach is followed that consists of presegmentation, anatomic orientation and structure segmentation. No user input or a priori information about the image content is required. In presegmentation, the body outline, the bones and lung equivalent tissue are detected. Anatomic orientation recognizes the patient's position, orientation and gender and creates an elastic mapping of the slice positions to a reference scale. Structure segmentation is divided into localization, outlining and refinement, performed by procedures with implicit ...

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A case of intrathoracic lipoma in a child is presented. The diagnosis was made before operation by means of computer-assisted tomography, a non-interventional procedure.

International Nuclear Information System (INIS)

Monte Carlo (MC) dose calculations can be accurate but are also computationally intensive. In contrast, convolution superposition (CS) offers faster and smoother results but by making approximations. We investigated MC denoising techniques, which use available convolution superposition results and new noise filtering methods to guide and accelerate MC calculations. Two main approaches were developed to combine CS information with MC denoising. In the first approach, the denoising result is iteratively updated by adding the denoised residual difference between the result and the MC image. Multi-scale methods were used (wavelets or contourlets) for denoising the residual. The iterations are initialized by the CS data. In the second approach, we used a frequency splitting technique by quadrature filtering to combine low frequency components derived from MC simulations with high frequency components derived from CS components. The rationale is to take the scattering ...

International Nuclear Information System (INIS)

Full text: Based on experience with nuclear material confiscated in Hungary from illicit trafficking activities in the nineties it has been decided that traditional gamma-spectrometry should be complemented by destructive analytical techniques. The 17/1996 (I. 31.) Korm. Governmental Decree delegated the identification, categorization and characterization tasks to the Institute of Isotopes, Budapest. Routine gamma-spectrometric methods have been further developed aiming at the i) age (production date) determination of seized samples and complete (nondismountable) uranium-bearing items (such as fresh fuel bundles and fission chambers) by HRGS technique, ii) improvement of measurement accuracy and reliability. Starting in 2005 mass spectrometry (ICP-SFMS) and scanning electron microscopy have been implemented to characterize nuclear samples in more detail and to analyze environmental samples both for isotopic and elemental composition focusing on long-lived radioactive isotopes including ...

International Nuclear Information System (INIS)

In order to predict or to evaluate the structural reliability of a variety of nuclear components under actual changing operating conditions, it is necessary to take the detailed geometrical features of components into consideration on one hand, and thermo-mechanical loading conditions with space and time variations during the lifetime, on the other hand. This consideration leads the authors to develop a super large-scale structural analysis program based on a parallel computational FEM with a variable scale of PC cluster architecture, whose prototype system is presented in a companion paper in this Symposium. Development of the PC cluster technology is one of the most important subjects in large-scale structural simulation, reducing computer costs and thus making simulation more acceptable to the engineering community. This paper presents the developmental status of the parallel FEM solver, demonstrating computational capabilities with three dimensional effects taking into ...

International Nuclear Information System (INIS)

A conventional PET scanner has a 15-25 cm axial field-of-view (FOV) and images a whole body using about six bed positions. An OpenPET geometry can extend the axial FOV with a limited number of detectors. The entire whole-body PET scanner must be able to process a large amount of data effectively. In this work, we study feasibility of the fully 3D entire whole-body PET scanner using the GATE simulation. The OpenPET has 12 block detector rings with the ring diameter of 840 mm and each block detector ring consists of 48 depth-of-interaction (DOI) detectors. The OpenPET has the axial length of 895.95 mm with five parts of 58.95 mm open gaps. The OpenPET has higher single data loss than a conventional PET scanner at grouping circuits. NECR of the OpenPET decreases by single data loss. But single data loss is mitigated by separating the axially arranged detector into two parts. Also, multiple coincidences are found to be ...

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I discuss several examples of critical phenomena in O(N) models where topological excitations play an important role at criticality. I focus particular attention on the O(2) model in 3D, where recent measurements of the vortex string length distribution in equilibrium suggest the existence of a quantitative picture of the critical behavior in terms of defects. The compatibility of this perspective with renormalization group predictions is examined.

UK PubMed Central (United Kingdom)

The non-natural pyrido[2,3-d]pyrimidine nucleoside F, which pairs preferentially with guanine (G) and adenine (A) within double-helical DNA, recognizes with high selectivity AT base pairs within triple-helical...Full Text Available

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The lowest excited level in Ni-like ions, 3d{sup 9}4s {sup 3}D{sub 3}, decays only via a magnetic octupole (M3) decay. They present calculated values of transition wavelengths and rates for ions with 30 {le} Z {le} 100. They have observed this line in Xe{sup 26+}, using the Livermore EBIT-I electron beam ion trap and a microcalorimeter, as well as a high-resolution flat-field grating spectrometer.

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Chemical influences on the relative Ksub(..beta..)/Ksub(..cap alpha..) x-ray intensity ratio up to five per cent were found for different chemical constitutions of Cr, Mn, Fe and Cu by very precise PIXE measurements. In the discussion of these effects, screening of 3p electrons by a varying 3d valence charge, as well as polarizational effects are of importance.

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We have studied the nucleation and growth processes in a chemical vapor deposition (CVD) diamond film using a tomographic electron backscattering diffraction method (3D EBSD). The approach is based on the combination of a focused ion beam (FIB) unit for serial sectioning in conjunction with high-resolution EBSD. Individual diamond grains were investigated in 3-dimensions particularly with regard to the role of twinning.

International Nuclear Information System (INIS)

Neurotensin (NT) and its high affinity receptor (NTR1) are involved in several neoplastic processes. Thus, NT-based radiopharmaceuticals are potential tracers for targeted diagnosis and therapy of NTR-positive tumours. A new analogue based on NT(8-13), NT-XIX, with the three enzymatic cleavage sites stabilised, was synthesised and tested. The synthesis was performed by Boc strategy. Labelling with "9"9"mTc/"1"8"8Re was performed using the tricarbonyl technique. Metabolic stability was tested in vitro and in vivo. NT-XIX was further characterised in vitro in HT-29 cells and in vivo in nude mice with HT-29 xenografts. NT-XIX showed much longer half-lives than non-stabilised analogues. Binding to NTR1 was highly specific, although the affinity was lower than that of natural NT. Bound activity rapidly internalised into HT-29 cells and 50% remained trapped after 24 h. In the time-course biodistribution, the highest uptake was found in the tumour at all p.i. times. In ...

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The Tomographic Gamma Scanning (TGS) technique is a relatively new method in the field of non-destructive assay (NDA) of radioactive waste. The TGS technique combines High Resolution Gamma Spectrometry (HRGS) with Three-Dimensional (3-D) low spatial resolution transmission and emission image reconstruction techniques to achieve assay goals. When compared to the traditional methods such as Segmented Gamma Scanning (SGS), the TGS technique can yield better accuracies for cases where the radionuclide is distributed non-uniformly in a heterogeneous matrix. The TGS technique is ideally suited for low-to-moderate density waste matrices, say 1.0 g cm{sup -3} or below for 55 US gal. drums, although it can be extended to higher densities by using alternative approaches to the design or analyses. Recently Canberra Industries designed, built and characterized four such TGS systems for nuclear power plant applications. Many of the ...

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An exhaustive compendium of normal and abnormal imaging is presented. The following systems and procedures are illustrated by over 2800 captioned illustrations: liver, spleen, and hepatobiliary imaging; perfusion and ventilation lung imaging; thyroid imaging; salivary gland imaging; bone imaging; brain imaging; radionuclide cisternography; blood flow studies; gallium imaging; nuclear cardiology; and renal imaging. Not included in the atlas are adrenal imaging procedures and emission computed tomography. (ERB)

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Purpose: The purpose of this study was to observe the process of fixation in liver specimens non-invasively by means of magnetic resonance. The fixation process of several formaldehyde-containing solutions was monitored with MRI and MRS at two different temperatures. Materials and Methods: Liver specimens were conserved in aqueous fixative solutions containing formaldehyde concentrations of 0.7, 1.8, 4 and 7.2% and at different temperatures of 5 C and 20 C. MRI was performed with T1-, T2- and PD-weighted TSE sequences, a 2D FLASH-sequence with and without magnetization transfer, and a FISP 3D-sequence on a clinical 1.5 Tesla MR whole-body unit, and MRS with {sup 1}H-spectroscopic methods (STEAM-sequence) on a 3 Tesla MR whole-body unit. Results: The diffusion of formaldehyde into the tissue was best identified on PD- and T1-weighted images as a band under the liver surface with increasing thickness, penetrating especially ...

International Nuclear Information System (INIS)

In a prospective study, 58 patients with carcinomas of the bladder were examined by CT and MRI; in 48, gadolinium-DTPA was administered intravenously. MRI provided exact staging in 89%, compared with 80% with CT. There was 13% over-staging with CT and 11% with MRI. MRI, unlike CT did not result in any under-staging. In 36 patients a quotient could be calculated from the signal intensity of the tumour and surrounding soft tissues both before and after the intravenous contrast medium and the increased quotient after contrast administration could be estimated. There was a significant increase in the tumour/muscle quotient with a mean of 72#+-#22% (minimum 43%, maximum 153%), corresponding to a marked increase of the signal form the tumour when compared with the precontrast images. This had the following advantages compared with CT: Accurate differentiation between superficial and intramural spread. MRI was better than CT at demonstrating tumours in the roof of the ...

International Nuclear Information System (INIS)

The introduction of positron emission tomography (PET)/magnetic resonance (MR) systems into medical practice in the foreseeable future may not only lead to a gain in clinical diagnosis compared to PET/computed tomography (CT) imaging due to the superior soft-tissue contrast of the MR technology but can also substantially reduce exposure of patients to ionizing radiation. On the other hand, there are also risks and health effects associated with the use of diagnostic MR devices that have to be considered carefully. This review article summarizes biophysical and biological aspects, which are of relevance for the assessment of health effects related to the exposure of patients to both ionizing radiation in PET and magnetic and electromagnetic fields in MR. On this basis, some considerations concerning the justification and optimization of PET/MR examinations are presented - as far as this is possible at this very early stage. Current safety ...

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Hepatobiliary scintigraphy is the only non-invasive technique providing real-time assessment of hepatocytes function and bile progression from the liver to the intestine; for this reason it is of great importance in the study of jaundice and many other disorders of the liver and the biliary tract in children. Ultrasonography is the initial method of evaluating the intra- and extrahepatic bile ducts dilatation: the differential diagnosis between biliary atresia and neonatal hepatitis cannot however be done without hepatobiliary scintigraphy. Cystic fibrosis patients also require hepatobiliary scintigraphy; liver and biliary tract disease can really occur independently of the underlying disease severity and the presence of steatorrhoea. Hepatobiliary imaging in children who have undergone liver transplantation is of major importance; it can assess vascularity, parenchymal function biliary drainage, possible presence of a bile leak and ...

International Nuclear Information System (INIS)

CT scans were performed on 25 patients suspected of sustaining ranal trauma. The utility of CT in both detecting renal damage and appraising the gravity of injuries was assessed. Nowadays, in fact, nephrectomy or reserved for lesions devastanting the kidney parenchyma or rupturing the renal pedicle; so it is very important to identyfy both the purposes of a better planned therapeutic approach. CT does both, being more accurate than urography in the detection of renal fractures, intra or extraparenchymal hematomas and contrast media extravasation. Urography very often shows aspecific lesion patterns and sometimes it is also falsely negative. In the present series CT was more reliable than angiography itself, particulary in the diagnosis of extra-renal hematic collections, contrast media extravasation and injuries to the other abdominal organs. Although CT may arouse the suspicion of and sometimes correctly diagnose vascular lesions, such as renal infarction, ...

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The relationship between serum PG I, PG II levels and extent of atrophic gastritis was examined. The subjects were 64 patients (male: 32, female: 32, 51.9 years old on average) with established diagnosis of either atrophic gastritis or normal. In the X-ray gastric examination, Fuji Computed Radiography (FCR) was used to obtain clear-cut images of the gastric area. Concerning the serum PG I level, patients in the group with atrophic gastritis showed lower levels than those of the people in the group with no atrophic change, but the variation was wide, and no definite tendency was seen in the relationship between the atrophic change and the serum PG I levels. Concerning the serum PG II level, as the atrophic change progresses, the serum PG II level tended to increase gradually. A significant reduction in the PG I/II ratio was seen in the group with atrophic changes (p<0.01) in comparison with the group with no atrophic changes, and the PG I/II ...

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Purpose: To describe the clinical aspects and evaluate optical coherence tomography of macular microholes. Methods: Seven patients were assessed (8 eyes) with microholes of the macula. All patients underwent complete eye examination, fundus photography, fluorescent angiography and OCT-3 imaging. Results: Ages ranged from 26 to 69 years. Six patients were female (85.7%) and five of them had microhole in the right eye. The presenting symptom was decrease in visual acuity (71.3%) and central scotoma in (14.3%). Five eyes (71.4%) had no defects shown by fluorescent angiography. A defect in the outer retina was demonstrated in all eyes on optical coherence tomography. The lesions were nonprogressive. Conclusion: Macular microholes are small lamellar defects in the outer retina. The condition is nonprogressive, generally unilateral and compatible with good visual acuity. Fundus biomicroscopy associated with an optical coherence tomography are the main elements in the ...

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Magnetic resonance imaging (MRI) as a diagnostic imaging tool relies on the generation of magnetic fields, whereas the computerized tomography (CT) uses X-radiation. The fundamental principle of MRI is the magnetic resonance of paramagnetic atomic nuclei. These nuclei, as e.g. protons (= hydrogen nuclei), are aligned in required orientation by application of a strong magnetic field. Upon simultaneous application of an electromagnetic high-frequency field perpendicular to the axis of the basic magnetic field, and in response to periodical changing of the electromagnetic field at a given frequency, the originally aligned paramagnetic nuclei are forced into a movement similar to that of a ``whipping top``. When the resonance frequency is shut off, the nuclei return to their former, aligned positions, inducing a weak signal in a coil. The series of signals generated by multiple repetition of this process of excitation of nuclei and their return to ...

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Computer tomography used in the diagnosis of tumours is described in the light of particularly great diagnostic difficulties in children. Computer tomography was applied in 12 cases. A high diagnostic value of this method was demonstrated, which makes possible a more accurate diagnosis of the position of the tumour, its size, and expanding tendency. The possibility of estimating healthy tissues and organs, and those with pathological changes on the basis of differences in their density with a detection threshold at 0.5% density difference facilitates not infrequently preoperative diagnosis raising the value of the method.

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Purpose: Liposarcoma is the most common soft tissue sarcoma in adults. The purpose of the study was to correlate MR imaging features with the four ICD subclasses. Methods: 28 patients with liposarcoma were examined preoperatively on a 1.0 T MRI system, using spin echo sequences, gradient echo imaging and STIR sequences. In all patients, classification of the liposarcomas was made by histologic diagnosis (ICD-10-M-classification). Results: Well differentiated liposarcomas (9 patients) showed a number of MRI features consistent with lipoma (well defined mass high signal intensity (SI) on T{sub 1} images, low signal on T{sub 2} images, no or only little signal increase of tumour tissue after contrast material application, no necrosis). Not well differentiated liposarcomas (myxoid 14 patients, pleomorphic three patients, round cell two patients) revealed the largest part of the mass to ...

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This document is a user`s manual for the Rn3D finite element code. Rn3D was developed to simulate gas flow and radon transport in variably saturated, nonisothermal porous media. The Rn3D model is applicable to a wide range of problems involving radon transport in soil because it can simulate either steady-state or transient flow and transport in one-, two- or three-dimensions (including radially symmetric two-dimensional problems). The porous materials may be heterogeneous and anisotropic. This manual describes all pertinent mathematics related to the governing, boundary, and constitutive equations of the model, as well as the development of the finite element equations used in the code. Instructions are given for constructing Rn3D input files and executing the code, as well as a description of all output files generated ...

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Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for ...

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Purpose: To evaluate a T{sub 2}-weighted URSE sequence for the assessment of pulmonary infiltrations in comparison to CT. Methods: 28 MRT scans of 22 patients with confirmed pneumonia were recorded on a 1.5 Tesla apparatus with an expiratory and diastolic triggered, T{sub 2}-weighted ultrafast-spin-echo sequence in axial slice mode with the following parameters: TR{sub eff}/T{sub E}/Turbofactor 2000-4000/90 ms/21-23; slice thickness/separation 6/0.6 mm; FOV 360 mm; 24 slices. 24 spiral CTs (sice thickness/table advance: 1-2 mm/10 mm) were available for comparison. The separate evaluation of MRTs and CTs was performed by three radiologists in a consensus procedure with regard to pulmonary lesions (e.g., infiltration, round foci, net patterns) and image quality of the MRTs (4-step scale). Results: In 71% of the cases the CTs and MRTs agreed with the diagnosis and representation of the lesions, in 25% MRT was superior. MRT was better for the ...

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The method, use and results of computer-aided diagnosis of bone tumours and tumour-like skeletal abnormalities in childhood are described. One hundred and twentyone histologically verified cases were analysed and subjected to computer-aided diagnosis. Statistical methods were used, resulting in an accuracy of 96.7% and 91.7% respectively. In order to obtain additional confirmation of the diagnosis, a so-called growth rate was calculated by the computer. This proved to be a reliable criterion for evaluating the biological behaviour of tumours, irrespective of the histological diagnosis. The reasons for misdiagnosis were discussed. Attention is drawn to the importance of an accurate analysis of the radiographs and its input into the computer.

British Library Electronic Table of Contents (United Kingdom)

Objectives To investigate the feasibility and reproducibility of measurements of nasal bone length using a three-dimensional (3D) ultrasound in the first trimester. Methods In a prospective study, 118 consecutive pregnant women attending for Down syndrome screening at 11-13 + 6 weeks were recruited. They had successful fetal nasal bone measurement by two-dimensional (2D) ultrasound by four operators. Three-dimensional volumes were recorded in the mid-sagittal plane of fetal profile by the fifth operator and examined using multiplanar techniques. Another independent investigator randomly compared his measurements with one of the four operators. Results In the subsequent 3D examination, the nasal bone length could be examined in 94 cases (79.7%). The mean difference between the 2D and 3D mea...

International Nuclear Information System (INIS)

A three-dimensional (3D) thermal-hydraulic model and a numerical procedure for the simulation and analysis of a steady-state, as well as transient operation of nuclear power plant components are presented. A two-fluid approach is applied to modelling of two-phase flow. Thermal-hydraulics of a horizontal steam generator in the WWER 1000 nuclear power plant has been simulated at the full load, steady-state operation. A comparison of the numerical results with data measured at the NPP Novovoronjezh shows good agreement. 3D numerical results can be used in plant design or retrofitting, in nuclear power plant operation and safety analysis and as improvement of existing one-dimensional thermal-hydraulics models of the horizontal steam generator which are assessed by system codes used for the nuclear power plant safety analyses. (author)

Science.gov (United States)

... Title : Optical Images Due to Lenses and Mirrors. ... Abstract : The properties of real and virtual images formed by lenses and mirrors are reviewed. ...

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To evaluate and compare MRI-based ovarian morphology in groups of women with polycystic ovary syndrome (PCOS) and controls. All PCOS cases (n = 44) had oligo-amenorrhoea and hyperandrogenism irrespective of ovarian morphology, and fulfilled NIH/Rotterdam diagnostic criteria for PCOS. All control women (n = 40) had normal menses and normoandrogenaemia. All subjects were of white British/Irish origin and pre-menopausal. Group comparisons were based on independent-sample t tests. Polycystic ovarian morphology was defined by at least 12 follicles 2-9 mm in diameter and/or an ovarian volume greater than 10 cm{sup 3}. Ovarian morphology differed significantly in PCOS cases and controls (follicle number geometric mean [SD range] 18.6 [9.9, 35.0] vs 6.6 [3.1, 14.2], unadjusted P = 1.3 x 10{sup -16}; calculated ovarian volume 8.8 cm{sup 3} [5.0, 15.5] vs 5.1 cm{sup 3} [2.5, 10.3], unadjusted P = 3.0 x 10{sup -7}; peripheral follicle location in 55% vs 18% of ovaries, P = 7.9 x 10{sup -6}; ...

International Nuclear Information System (INIS)

The authors carried out a retrospective study on 4 years' work on a series of patients with proved active tuberculosis examined in the Departments of Bronchopneumology and Infectious Disease of the Arezzo Civil Hospital. The population was heterogenerous from the immunologic viewpoint. This paper compared the effectiveness of Computed Tomography (CT) with that of conventional chest radiography (CR) in the diagnosis and prognosis of tuberculosis. All patients underwent chest CR in double projection and conventional CT studies of the chest; 16 patients were also submitted to high resolution CT (HRCT). Consolidation was the most frequent parenchymal lesion in immunocompetent patients; it was often associated with cavitation, with no clear topographic prevalence in the upper lobes. Pleural effusion, as the only sign of disease and with empyema features, was found in 10 immunocompetent patients. No predominant pattern was found in the other two groups, even though ...

KoreaScience (Korea)

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Science.gov (United States)

Jun 10, 2011 ... Subsonic flow past a semi-infinite flat plate is modeled at Reynolds number 6 ..... data is taken from Cook, McDonald, and Firmin, AGARD-AR-138, 1979, p. ...... too large a time-averaged separation bubble behind the hump. ...

UK PubMed Central (United Kingdom)

A robust technique for determining the principal axes of a 3D shape represented by a point set, possibly with noise, is presented. We use techniques from robust statistics to guide the classical...Full Text Available

CERN Document Server

We propose the Particle Swarm Optimization (PSO) as an alternative method for locating periodic orbits in a three--dimensional (3D) model of barred galaxies. We develop an appropriate scheme that transforms the problem of finding periodic orbits into the problem of detecting global minimizers of a function, which is defined on the Poincar\\'{e} Surface of Section (PSS) of the Hamiltonian system. By combining the PSO method with deflection techniques, we succeeded in tracing systematically several periodic orbits of the system. The method succeeded in tracing the initial conditions of periodic orbits in cases where Newton iterative techniques had difficulties. In particular, we found families of 2D and 3D periodic orbits associated with the inner 8:1 to 12:1 resonances, between the radial 4:1 and corotation resonances of our 3D Ferrers bar model. The main ...

UK PubMed Central (United Kingdom)

There has been a controversy as to whether or not the non-pathological flat foot and high-arched foot have an effect on human walking activities. The 3D foot scanning system was employed to obtain static...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Metacad is a collection of routines which creates a randomly accessible data structure from Applicon's APPLE-3D data format and supplies a logical method for manipulation of the data structure by a CAD application program.

Energy Technology Data Exchange (ETDEWEB)

Experiments are performed to investigate the single-phase flow and flow-boiling heat transfer augmentation in 3D internally finned and micro-finned helical tubes. The tests for single-phase flow heat transfer augmentation are carried out in helical tubes with a curvature of 0.0663 and a length of 1.15 m, and the examined range of the Reynolds number varies from 1000 to 8500. Within the applied range of Reynolds number, compared with the smooth helical tube, the average heat transfer augmentation ratio for the two finned tubes is 71% and 103%, but associated with a flow resistance increase of 90% and 140%, respectively. A higher fin height gives a higher heat transfer rate and a larger friction flow resistance. The tests for flow-boiling heat transfer are carried out in 3D internally micro-finned helical tube with a curvature of 0.0605 and a length of 0.668 m. Compared with that in the smooth helical ...

Science.gov (United States)

Electrospun nanofibers composed of biodegradable polymers are attractive candidates for cell culture scaffolds in tissue engineering. Their fine-meshed structures, resembling natural extracellular matrices, effectively interact with cell surfaces and promote cell proliferation. The application of electrospinning, however, is limited to two-dimensional (2D) or single tube-like scaffolds, and the fabrication of arbitrary three-dimensional (3D) scaffolds from electrospun nanofibers is still very difficult due to the fibers' continuous and entangled form. To address this issue, in this paper, we describe the use of phase-separation-assisted electrospray and electrostatic focusing to perform continuous direct 3D patterning of nanofibrous microcapsules of biodegradable polylactic acid (PLA). These microcapsules exhibit fiber-particle duality because they are composed of nanofibers suitable for cell attachment ...

International Nuclear Information System (INIS)

Neutron semiconductor detectors for neutron counting and neutron radiography have an increasing importance. Simple silicon neutron detectors are combination of a planar diode with a layer of an appropriate neutron converter such as 6LiF. These devices have limited detection efficiency of not more than 5%. The detection efficiency can be increased by creating a 3D microstructure of dips, trenches or pores in the detector and filling it with a neutron converter. The first results related to the development of such devices are presented. Silicon detectors were fabricated with pyramidal dips on the surface covered with 6LiF and then irradiated by thermal neutrons. Pulse height spectra of the energy deposited in the sensitive volume were compared with simulations. The detection efficiency of these devices was about 6.3%. Samples with different column sizes were fabricated to study the electrical properties of ...

International Nuclear Information System (INIS)

This paper presents a new methodology to create realistic 3D microstructures of polycrystals. The virtual microstructures are based on statistical data describing the morphological and crystallographic textures of a sample, obtained from an EBSD analysis. In addition, the methodology can reproduce the observed surface on top of the simulated microstructure. This feature allows finite element calculations on these virtual aggregates to be compared to experimental results of mechanical tests. Such a comparison leads to the identification of the mechanical parameters of constitutive laws, such as critical resolved shear stress and strain hardening, using an optimization algorithm. Two materials were simulated in this study: TiAl and grade 702 zirconium. The first one presents twins inside the microstructure and the second one has an anisotropic texture. Based on 2D simulations, the important parameters necessary to describe a microstructure were ...

International Nuclear Information System (INIS)

The measurement of K(alpha)/K(beta) X-ray intensity ratio indicates the excitation process and the chemical state of the atom examined. Theoretical considerations on the origin of this property are presented. The difference of these ratios following photoionization and electron capture are calculated by a computer code generating transition matrix elements. The theoretical assumptions involved in the codes are tested by comparing the experimental and calculated data concerning 3d transition element atoms. (D.Gy.).

British Library Electronic Table of Contents (United Kingdom)

The term biological motion is often used by researchers studying the patterns of movement generated by living forms and in sports. We studied a pattern recognition system of motion in sport using biological motion data. Biological motion data are acquired using a 3D motion capture system. However, 3D motion capture systems are very expensive. In this article, a biological motion capture system was built using acceleration sensors. Our proposed system uses the technique of Gaussian fitting and regression analysis. We tested our proposed system in pattern recognition of outdoor tennis and its evaluations.