WorldWideScience

Sample records for tomographic image guidance

  1. Cone Beam Computed Tomographic imaging in orthodontics.

    Science.gov (United States)

    Scarfe, W C; Azevedo, B; Toghyani, S; Farman, A G

    2017-03-01

    Over the last 15 years, cone beam computed tomographic (CBCT) imaging has emerged as an important supplemental radiographic technique for orthodontic diagnosis and treatment planning, especially in situations which require an understanding of the complex anatomic relationships and surrounding structures of the maxillofacial skeleton. CBCT imaging provides unique features and advantages to enhance orthodontic practice over conventional extraoral radiographic imaging. While it is the responsibility of each practitioner to make a decision, in tandem with the patient/family, consensus-derived, evidence-based clinical guidelines are available to assist the clinician in the decision-making process. Specific recommendations provide selection guidance based on variables such as phase of treatment, clinically-assessed treatment difficulty, the presence of dental and/or skeletal modifying conditions, and pathology. CBCT imaging in orthodontics should always be considered wisely as children have conservatively, on average, a three to five times greater radiation risk compared with adults for the same exposure. The purpose of this paper is to provide an understanding of the operation of CBCT equipment as it relates to image quality and dose, highlight the benefits of the technique in orthodontic practice, and provide guidance on appropriate clinical use with respect to radiation dose and relative risk, particularly for the paediatric patient. © 2017 Australian Dental Association.

  2. Tomographic image reconstruction using training images

    DEFF Research Database (Denmark)

    Soltani, Sara; Andersen, Martin Skovgaard; Hansen, Per Christian

    2017-01-01

    We describe and examine an algorithm for tomographic image reconstruction where prior knowledge about the solution is available in the form of training images. We first construct a non-negative dictionary based on prototype elements from the training images; this problem is formulated within...

  3. Terahertz wave tomographic imaging with a Fresnel lens

    Institute of Scientific and Technical Information of China (English)

    S. Wang; X.-C. Zhang

    2003-01-01

    We demonstrate three-dimensional tomographic imaging using a Fresnel lens with broadband terahertz pulses. Objects at various locations along the beam propagation path are uniquely imaged on the same imaging plane using a Fresnel lens with different frequencies of the imaging beam. This procedure allows the reconstruction of an object's tomographic contrast image by assembling the frequency-dependent images.

  4. Blunt oesophageal perforation: treatment with surgical exclusion and percutaneous drainage under computed tomographic guidance

    International Nuclear Information System (INIS)

    Vauthey, J.N.; Lerut, J.; Laube, M.; Gertsch, P.

    1992-01-01

    We report a patient with a left thoracic contusion and rupture of the distal oesophagus. Persistent sepsis developed after oesophageal exclusion without closure. Two collection were drained percutaneously under computed tomographic guidance and the sepsis resolved. (11 refs., 1 fig.)

  5. Tomographic Particle Image Velocimetry Using Colored Shadow Imaging

    KAUST Repository

    Alarfaj, Meshal K.

    2016-02-01

    Tomographic Particle Image Velocimetry Using Colored Shadow Imaging by Meshal K Alarfaj, Master of Science King Abdullah University of Science & Technology, 2015 Tomographic Particle image velocimetry (PIV) is a recent PIV method capable of reconstructing the full 3D velocity field of complex flows, within a 3-D volume. For nearly the last decade, it has become the most powerful tool for study of turbulent velocity fields and promises great advancements in the study of fluid mechanics. Among the early published studies, a good number of researches have suggested enhancements and optimizations of different aspects of this technique to improve the effectiveness. One major aspect, which is the core of the present work, is related to reducing the cost of the Tomographic PIV setup. In this thesis, we attempt to reduce this cost by using an experimental setup exploiting 4 commercial digital still cameras in combination with low-cost Light emitting diodes (LEDs). We use two different colors to distinguish the two light pulses. By using colored shadows with red and green LEDs, we can identify the particle locations within the measurement volume, at the two different times, thereby allowing calculation of the velocities. The present work tests this technique on the flows patterns of a jet ejected from a tube in a water tank. Results from the images processing are presented and challenges discussed.

  6. Generalized Row-Action Methods for Tomographic Imaging

    DEFF Research Database (Denmark)

    Andersen, Martin Skovgaard; Hansen, Per Christian

    2014-01-01

    Row-action methods play an important role in tomographic image reconstruction. Many such methods can be viewed as incremental gradient methods for minimizing a sum of a large number of convex functions, and despite their relatively poor global rate of convergence, these methods often exhibit fast...... initial convergence which is desirable in applications where a low-accuracy solution is acceptable. In this paper, we propose relaxed variants of a class of incremental proximal gradient methods, and these variants generalize many existing row-action methods for tomographic imaging. Moreover, they allow...

  7. Comparative study of the macroscopic finding, conventional tomographic imaging, and computed tomographic imaging in locating the mandibular canal

    International Nuclear Information System (INIS)

    Choi, Hang Moon; You, Dong Soo

    1995-01-01

    The purpose of this study was comparison of conventional tomography with reformatted computed tomography for dental implant in locating the mandibular canal. Five dogs were used and after conventional tomographs and fitted computed tomographs were taken, four dentist traced all films. Mandibles were sectioned with 2 mm slice thickness and the sections were then radiographed (contact radiography). Each radiograpic image was traced and linear measurements were made from mandibular canal to alveolar crest, buccal cortex, lingual cortex, and inferior border. The following results were obtained; 1. Reformatted computed tomographs were exacter than conventional tomography by alveolar crest to canal length of -0.6 mm difference between real values and radiographs 2. The average measurements of buccal cortex to mandibular canal width and lingual cortex to mandibular canal width of conventional tomographs were exacter than reformatted computed tomographs, but standard deviations were higher than reformatted computed tomographs. 3. Standard deviations of reformatted computed tomographs were lower than conventional tomographs at all comparing sites 4. At reformatted computed tomography 62.5% of the measurements performed were within ±1 mm of the true value, and at conventional tomography 24.1% were. 5. Mandibular canal invisibility was 0.8% at reformatted computed tomography and 9.2% at conventional tomography. Reformatted computed tomography has been shown to be more useful radiographic technique for assessment of the mandibular canal than conventional tomography.

  8. Tomographic Image Reconstruction Using Training Images with Matrix and Tensor Formulations

    DEFF Research Database (Denmark)

    Soltani, Sara

    the image resolution compared to a classical reconstruction method such as Filtered Back Projection (FBP). Some priors for the tomographic reconstruction take the form of cross-section images of similar objects, providing a set of the so-called training images, that hold the key to the structural......Reducing X-ray exposure while maintaining the image quality is a major challenge in computed tomography (CT); since the imperfect data produced from the few view and/or low intensity projections results in low-quality images that are suffering from severe artifacts when using conventional...... information about the solution. The training images must be reliable and application-specific. This PhD project aims at providing a mathematical and computational framework for the use of training sets as non-parametric priors for the solution in tomographic image reconstruction. Through an unsupervised...

  9. Correction of ring artifacts in X-ray tomographic images

    DEFF Research Database (Denmark)

    Lyckegaard, Allan; Johnson, G.; Tafforeau, P.

    2011-01-01

    Ring artifacts are systematic intensity distortions located on concentric circles in reconstructed tomographic X-ray images. When using X-ray tomography to study for instance low-contrast grain boundaries in metals it is crucial to correct for the ring artifacts in the images as they may have...... the same intensity level as the grain boundaries and thus make it impossible to perform grain segmentation. This paper describes an implementation of a method for correcting the ring artifacts in tomographic X-ray images of simple objects such as metal samples where the object and the background...... are separable. The method is implemented in Matlab, it works with very little user interaction and may run in parallel on a cluster if applied to a whole stack of images. The strength and robustness of the method implemented will be demonstrated on three tomographic X-ray data sets: a mono-phase β...

  10. A study of the decoding of multiple pinhole coded aperture RI tomographic images

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Kobayashi, Akitoshi; Nishiyama, Yutaka

    1980-01-01

    The authors constructed a Multiple Pinhole Coded Aperture (MPCA) and developed related decoding software. When simple coordinate transformation was performed, omission of points and shifting of counts occurred. By selecting various tomographic planes and collecting count for each tomographic depth from the shadowgram, a solution to these problems was found. The counts from the central portion of the tomographic image from the MPCA were incorrectly high, this was rectified by a correction function to improve the uniformity correction program of the γ-camera. Depth resolution of the tomographic image improved in proportion to the area encompassed by the pinhole configuration. An MPCA with a uniform arrangement of pinholes (e, g, pinholes in an arrangement parallel to the X-axis or the Y-axis) yielded decoded tomographic images of inferior quality. Optimum results were obtained with a ring-shaped arrangement yielding clinically applicable tomographic images even for large objects. (author)

  11. Remote diagnosis via a telecommunication satellite--ultrasonic tomographic image transmission experiments.

    Science.gov (United States)

    Nakajima, I; Inokuchi, S; Tajima, T; Takahashi, T

    1985-04-01

    An experiment to transmit ultrasonic tomographic section images required for remote medical diagnosis and care was conducted using the mobile telecommunication satellite OSCAR-10. The images received showed the intestinal condition of a patient incapable of verbal communication, however the image screen had a fairly coarse particle structure. On the basis of these experiments, were considered as the transmission of ultrasonic tomographic images extremely effective in remote diagnosis.

  12. Construction of tomographic head model using sectioned photographic images of cadaver

    International Nuclear Information System (INIS)

    Lee, Choon Sik; Lee, Jai Ki; Park, Jin Seo; Chung, Min Suk

    2004-01-01

    Tomographic models are currently the most complete, developed and realistic models of the human anatomy. They have been used to estimate organ doses for diagnostic radiation examination and radiotherapy treatment planning, and radiation protection. The quality of original anatomic images is a key factor to build a quality tomographic model. Computed tomography (CT) and magnetic resonance imaging (MRI) scan, from which most of current tomographic models are constructed, have their inherent shortcomings. In this study, a tomographic model of Korean adult male head was constructed by using serially sectioned photographs of cadaver. The cadaver was embedded, frozen, serially sectioned and photographed by high resolution digital camera at 0.2 mm interval. The contours of organs and tissues in photographs were segmented by several trained anatomists. The 120 segmented images of head at 2mm interval were converted into binary files and ported into Monte Carlo code to perform an example calculation of organ dose. Whole body tomographic model will be constructed by using the procedure developed in this study

  13. Image Guidance

    Science.gov (United States)

    Guidance that explains the process for getting images approved in One EPA Web microsites and resource directories. includes an appendix that shows examples of what makes some images better than others, how some images convey meaning more than others

  14. Advantages of computed tomographic guidance

    International Nuclear Information System (INIS)

    Casola, G.; Vansonnenberg, E.

    1987-01-01

    Both ultrasound and CT are successfully used to guide interventional procedures throughout the body. There are advantages and disadvantages to each modality and choosing one over the other will vary from case to case. Major factors influencing choice are discussed in this paper. As a general rule CT guidance is usually required for lesions in the thorax, the adrenals, the pancreas, lymph nodes, and for percutaneous abscess drainage. The authors feel that a complimentary use of ultrasound and CT is essential to optimize success and cost-effectiveness; therefore, the interventional radiologist should be familiar with both imaging modalities

  15. Tomographic images of cerebral blood flow using a slant hole collimator

    International Nuclear Information System (INIS)

    Wraight, E.P.; Barber, R.W.; Crossland, P.; Maltby, P.

    1983-01-01

    The feasibility of using a rotating slant hole (RSH) collimator on simple tomographic equipment such as a standard gamma camera interfaced to a general purpose Nuclear Medicine computer is reported for producing images of cerebral blood flow following the administration of 123 I-iodoamphetamine to patients. Initial studies produced satisfactory images, thus opening the possibility of tomographic cerebral blood flow imaging to centres not possessing sophisticated tomographic equipment. Planar resolution is superior to that reported for a 25 0 RSH collimator. Axial resolution is not as good at small source distances but is comparable at distances beyond 10 cm. Sensitivity is comparable to other RSH collimators and is similar to Technicare's parallel hole general all purpose collimator. (UK)

  16. Connections model for tomographic images reconstruction

    International Nuclear Information System (INIS)

    Rodrigues, R.G.S.; Pela, C.A.; Roque, S.F. A.C.

    1998-01-01

    This paper shows an artificial neural network with an adequately topology for tomographic image reconstruction. The associated error function is derived and the learning algorithm is make. The simulated results are presented and demonstrate the existence of a generalized solution for nets with linear activation function. (Author)

  17. Positioning of Nuclear Fuel Assemblies by Means of Image Analysis on Tomographic Data

    International Nuclear Information System (INIS)

    Troeng, Mats

    2005-06-01

    A tomographic measurement technique for nuclear fuel assemblies has been developed at the Department of Radiation Sciences at Uppsala University. The technique requires highly accurate information about the position of the measured nuclear fuel assembly relative to the measurement equipment. In experimental campaigns performed earlier, separate positioning measurements have therefore been performed in connection to the tomographic measurements. In this work, another positioning approach has been investigated, which requires only the collection of tomographic data. Here, a simplified tomographic reconstruction is performed, whereby an image is obtained. By performing image analysis on this image, the lateral and angular position of the fuel assembly can be determined. The position information can then be used to perform a more accurate tomographic reconstruction involving detailed physical modeling. Two image analysis techniques have been developed in this work. The stability of the two techniques with respect to some central parameters has been studied. The agreement between these image analysis techniques and the previously used positioning technique was found to meet the desired requirements. Furthermore, it has been shown that the image analysis techniques offer more detailed information than the previous technique. In addition, its off-line analysis properties reduce the need for valuable measurement time. When utilizing the positions obtained from the image analysis techniques in tomographic reconstructions of the rod-by-rod power distribution, the repeatability of the reconstructed values was improved. Furthermore, the reconstructions resulted in better agreement to theoretical data

  18. Time-resolved tomographic images of a relativistic electron beam

    International Nuclear Information System (INIS)

    Koehler, H.A.; Jacoby, B.A.; Nelson, M.

    1984-07-01

    We obtained a sequential series of time-resolved tomographic two-dimensional images of a 4.5-MeV, 6-kA, 30-ns electron beam. Three linear fiber-optic arrays of 30 or 60 fibers each were positioned around the beam axis at 0 0 , 61 0 , and 117 0 . The beam interacting with nitrogen at 20 Torr emitted light that was focused onto the fiber arrays and transmitted to a streak camera where the data were recorded on film. The film was digitized, and two-dimensional images were reconstructed using the maximum-entropy tomographic technique. These images were then combined to produce an ultra-high-speed movie of the electron-beam pulse

  19. Reconstruction of tomographic image from x-ray projections of a few views

    International Nuclear Information System (INIS)

    Kobayashi, Fujio; Yamaguchi, Shoichiro

    1982-01-01

    Computer tomographs have progressed rapidly, and in the latest high performance types, the photographing time has been shortened to less than 5 sec, but the clear images of hearts have not yet been obtained. The X-ray tomographs used so far irradiate X-ray from many directions and measure the projected data, but by limiting projection direction to a small number, it was planned to shorter the X-ray photographing time and to reduce X-ray exposure as the objective of this study. In this paper, a method is proposed, by which tomographic images are reconstructed from projected data in a small number of direction by generalized inverse matrix penalty method. This method is the calculation method newly devised by the authors for this purpose. It is a kind of the nonlinear planning method added with the restrictive condition using a generalized inverse matrix, and it is characterized by the simple calculation procedure and rapid convergence. Moreover, the effect on reconstructed images when errors are included in projected data was examined. Also, the simple computer simulation to reconstruct tomographic images using the projected data in four directions was performed, and the usefulness of this method was confirmed. It contributes to the development of superhigh speed tomographs in future. (Kako, I.)

  20. A study of the decoding of multiple pinhole coded aperture RI tomographic images

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Kobayashi, Akitoshi; Nishiyama, Yutaka; Akagi, Kiyoshi; Uehata, Hiroshi

    1981-01-01

    In order to obtain a radioisotope (RI) tomographic image, there are various, methods, including the RCT method, Time Modulate method, and Multiple Pinhole Coded Aperture (MPCA) method and others. The MPCA method has several advantages. Using the MPCA method, there is no need to move either the detector or the patient, Furthermore, the generally used γ-camera may be used without any alterations. Due to certain problems in reconstructing the tomographic image, the use of the MPCA method in clinical practice is limited to representation of small organs (e.g. heart) using the 7-Pinhole collimator. This research presents an experimental approach to overcome the problems in reconstruction of tomographic images of large organs (organs other than the heart, such as the brain, liver, lung etc.) by introducing a reconstruction algorithm and correction software into the MPCA method. There are 2 main problems in MPCA image reconstruction: (1) Due to the rounding-off procedure, there is both point omission and shifting of point coordinates. (2) The central portion is characterized by high-counts. Both of these problems were solved by incorporating a reconstruction algorithm and a correction function. The resultant corrected tomographic image was processed using a filter derived from subjecting a PSF to a Fourier transform. Thus, it has become possible to obtain a high-quality tomographic image of large organs for clinical use. (author)

  1. Tomographic image via background subtraction using an x-ray projection image and a priori computed tomography

    International Nuclear Information System (INIS)

    Zhang Jin; Yi Byongyong; Lasio, Giovanni; Suntharalingam, Mohan; Yu, Cedric

    2009-01-01

    Kilovoltage x-ray projection images (kV images for brevity) are increasingly available in image guided radiotherapy (IGRT) for patient positioning. These images are two-dimensional (2D) projections of a three-dimensional (3D) object along the x-ray beam direction. Projecting a 3D object onto a plane may lead to ambiguities in the identification of anatomical structures and to poor contrast in kV images. Therefore, the use of kV images in IGRT is mainly limited to bony landmark alignments. This work proposes a novel subtraction technique that isolates a slice of interest (SOI) from a kV image with the assistance of a priori information from a previous CT scan. The method separates structural information within a preselected SOI by suppressing contributions to the unprocessed projection from out-of-SOI-plane structures. Up to a five-fold increase in the contrast-to-noise ratios (CNRs) was observed in selected regions of the isolated SOI, when compared to the original unprocessed kV image. The tomographic image via background subtraction (TIBS) technique aims to provide a quick snapshot of the slice of interest with greatly enhanced image contrast over conventional kV x-ray projections for fast and accurate image guidance of radiation therapy. With further refinements, TIBS could, in principle, provide real-time tumor localization using gantry-mounted x-ray imaging systems without the need for implanted markers.

  2. Terahertz Imaging for Biomedical Applications Pattern Recognition and Tomographic Reconstruction

    CERN Document Server

    Yin, Xiaoxia; Abbott, Derek

    2012-01-01

    Terahertz Imaging for Biomedical Applications: Pattern Recognition and Tomographic Reconstruction presents the necessary algorithms needed to assist screening, diagnosis, and treatment, and these algorithms will play a critical role in the accurate detection of abnormalities present in biomedical imaging. Terahertz biomedical imaging has become an area of interest due to its ability to simultaneously acquire both image and spectral information. Terahertz imaging systems are being commercialized with an increasing number of trials performed in a biomedical setting. Terahertz tomographic imaging and detection technology contributes to the ability to identify opaque objects with clear boundaries,and would be useful to both in vivo and ex vivo environments. This book also: Introduces terahertz radiation techniques and provides a number of topical examples of signal and image processing, as well as machine learning Presents the most recent developments in an emerging field, terahertz radiation Utilizes new methods...

  3. Visual servoing in medical robotics: a survey. Part II: tomographic imaging modalities--techniques and applications.

    Science.gov (United States)

    Azizian, Mahdi; Najmaei, Nima; Khoshnam, Mahta; Patel, Rajni

    2015-03-01

    Intraoperative application of tomographic imaging techniques provides a means of visual servoing for objects beneath the surface of organs. The focus of this survey is on therapeutic and diagnostic medical applications where tomographic imaging is used in visual servoing. To this end, a comprehensive search of the electronic databases was completed for the period 2000-2013. Existing techniques and products are categorized and studied, based on the imaging modality and their medical applications. This part complements Part I of the survey, which covers visual servoing techniques using endoscopic imaging and direct vision. The main challenges in using visual servoing based on tomographic images have been identified. 'Supervised automation of medical robotics' is found to be a major trend in this field and ultrasound is the most commonly used tomographic modality for visual servoing. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Automated angular and translational tomographic alignment and application to phase-contrast imaging

    DEFF Research Database (Denmark)

    Cunha Ramos, Tiago Joao; Jørgensen, Jakob Sauer; Andreasen, Jens Wenzel

    2017-01-01

    X-ray computerized tomography (CT) is a 3D imaging technique that makes use of x-ray illumination and image reconstruction techniques to reproduce the internal cross-sections of a sample. Tomographic projection data usually require an initial relative alignment or knowledge of the exact object po...... improvement in the reconstruction resolution. A MATLAB implementation is made publicly available and will allow robust analysis of large volumes of phase-contrast tomography data.......X-ray computerized tomography (CT) is a 3D imaging technique that makes use of x-ray illumination and image reconstruction techniques to reproduce the internal cross-sections of a sample. Tomographic projection data usually require an initial relative alignment or knowledge of the exact object...... reconstruction artifacts and limit the attained resolution in the final tomographic reconstruction. Alignment algorithms that require manual interaction impede data analysis with ever-increasing data acquisition rates, supplied by more brilliant sources. We present in this paper an iterative reconstruction...

  5. A new algorithm for γ-ray tomographic imaging using a scintillation camera

    International Nuclear Information System (INIS)

    Terajima, Hirokatsu; Nakajima, Masato; Itoh, Takashi.

    1979-01-01

    The gamma ray tomographic imaging giving 3-dimensional distribution of RI in human bodies is being actively investigated for the reason that the conventional images are of 2-dimensional projection, but it is not yet employed practically, because there are some problems in the tomographic image quality obtained. One of the methods is a technique to determine the radioisotope distribution on each tomographic plane by placing a planar detector in parallel with the assumed tomographic planes and by processing the 2-dimensional radioisotope projection images thus obtained. It does not require the repetition of reconstructive algorithm. The authors have proposed the algorithm for this method, and have carried out the experiments to verify the propriety of the algorithm. Radioisotope phantom is composed of the overlapping acrylic cubic vessels of 30 mm sides containing radioisotopes arranged 2-dimensionally in each layer, and the multi-pinhole shutter array is used as the collimator. The projection image of radioisotope distribution on the scintillator face is converted into the digital imaging data sampled in 2-dimensional space of 64 x 64 with the mini-computer. Among the probable causes to affect the reconstructed image quality, statistical fluctuation, absorption of gamma ray and the shape of aperture for the collimator are discussed. These indicate that this method is more effective than the conventional methods, and can be the effective technique for medical diagnosis and therapy, because this is a technique to determine 3-dimensional distribution of RI by utilizing existing equipments. (Wakatsuki, Y.)

  6. Image interface in Java for tomographic reconstruction in nuclear medicine

    International Nuclear Information System (INIS)

    Andrade, M.A.; Silva, A.M. Marques da

    2004-01-01

    The aim of this study is to implement a software for tomographic reconstruction of SPECT data from Nuclear Medicine with a flexible interface design, cross-platform, written in Java. Validation tests were performed based on SPECT simulated data. The results showed that the implemented algorithms and filters agree with the theoretical context. We intend to extend the system by implementing additional tomographic reconstruction techniques and Java threads, in order to provide simultaneously image processing. (author)

  7. ECAT: a new computerized tomographic imaging system for position-emitting radiopharmaceuticals

    International Nuclear Information System (INIS)

    Phelps, M.E.; Hoffman, E.J.; Huang, S.C.; Kuhl, D.E.

    1977-01-01

    The ECAT was designed and developed as a complete computerized positron radionuclide imaging system capable of providing high contrast, high resolution, quantitative images in 2 dimensional and tomographic formats. Flexibility, in its various image mode options, allows it to be used for a wide variety of imaging problems

  8. Tomographic imaging of subducted lithosphere below northwest Pacific island arcs

    Science.gov (United States)

    Van Der Hilst, R.; Engdahl, R.; Spakman, W.; Nolet, G.

    1991-01-01

    The seismic tomography problem does not have a unique solution, and published tomographic images have been equivocal with regard to the deep structure of subducting slabs. An improved tomographic method, using a more realistic background Earth model and surf ace-reflected as well as direct seismic phases, shows that slabs beneath the Japan and Izu Bonin island arcs are deflected at the boundary between upper and lower mantle, whereas those beneath the northern Kuril and Mariana arcs sink into the lower mantle.

  9. Unfolding and smoothing applied to the quality enhancement of neutron tomographic images

    International Nuclear Information System (INIS)

    Almeida, Gevaldo L. de; Silvani, Maria I.; Lopes, Ricardo T.

    2008-01-01

    Resolution and contrast are the major parameters defining the quality of a computer-aided tomographic image. These parameters depend upon several features of the image acquisition system, such as detector resolution, geometrical arrangement of the source-object-detector, beam divergence, source strength, detector efficiency and counting time. Roughly, the detector finite resolution is the main source of systematic errors affecting the separation power of the image acquisition system, while the electronic noise and statistical fluctuation are responsible for the data dispersion, which spoils the contrast. An algorithm has been developed in this work aiming at the improvement of the image quality through the minimization of both types of errors. The systematic ones are reduced by a mathematical unfolding of the position spectra - used as projections to reconstruct the 2D-images - using the Line Spread Function - LSF of the neutron tomographic system. The principle behind this technique is that every single channel contains information about all channels of the spectrum, but it is concealed due to the automatic integration carried out by the detector. Therefore, knowing the shape of this curve, it is possible to retrieve the original spectra. These spectra are unfortunately corrupted by the unavoidable statistical fluctuation, and by oscillations arising from the unfolding process, which strongly affects the quality of the final unfolded image. In order to reduce this impact, the spectra have been filtered by a Fourier transform technique or smoothed with a least square fitting procedure. The algorithm has been applied to spectra of some test-bodies generated by an earlier developed tomographic simulator, which reproduces the spectra furnished by a thermal neutron tomographic system employing a position sensitive detector. The obtained results have shown that the unfolded spectra produce final images capable to resolve features otherwise not achievable with the

  10. Cone-Beam Computed Tomographic Image Guidance for Lung Cancer Radiation Therapy

    International Nuclear Information System (INIS)

    Bissonnette, Jean-Pierre; Purdie, Thomas G.; Higgins, Jane A.; Li, Winnie; Bezjak, Andrea

    2009-01-01

    Purpose: To determine the geometric accuracy of lung cancer radiotherapy using daily volumetric, cone-beam CT (CBCT) image guidance and online couch position adjustment. Methods and Materials: Initial setup accuracy using localization CBCT was analyzed in three lung cancer patient cohorts. The first (n = 19) involved patients with early-stage non-small-cell lung cancer (NSCLC) treated using stereotactic body radiotherapy (SBRT). The second (n = 48) and third groups (n = 20) involved patients with locally advanced NSCLC adjusted with manual and remote-controlled couch adjustment, respectively. For each group, the couch position was adjusted when positional discrepancies exceeded ±3 mm in any direction, with the remote-controlled couch correcting all three directions simultaneously. Adjustment accuracy was verified with a second CBCT. Population-based setup margins were derived from systematic (Σ) and random (σ) positional errors for each group. Results: Localization imaging demonstrates that 3D positioning errors exceeding 5 mm occur in 54.5% of all delivered fractions. CBCT reduces these errors; post-correction Σ and σ ranged from 1.2 to 1.9 mm for Group 1, with 82% of all fractions within ±3 mm. For Group 2, Σ and σ ranged between 0.8 and 1.8 mm, with 76% of all treatment fractions within ±3 mm. For Group 3, the remote-controlled couch raised this to 84%, and Σ and σ were reduced to 0.4 to 1.7 mm. For each group, the postcorrection setup margins were 4 to 6 mm, 3 to 4 mm, and 2 to 3 mm, respectively. Conclusions: Using IGRT, high geometric accuracy is achievable for NSCLC patients, potentially leading to reduced PTV margins, improved outcomes and empowering adaptive radiation therapy for lung cancer

  11. Tomographic Particle Image Velocimetry using Smartphones and Colored Shadows

    KAUST Repository

    Aguirre-Pablo, Andres A.; Alarfaj, Meshal K.; Li, Erqiang; Hernandez Sanchez, Jose Federico; Thoroddsen, Sigurdur T

    2017-01-01

    We demonstrate the viability of using four low-cost smartphone cameras to perform Tomographic PIV. We use colored shadows to imprint two or three different time-steps on the same image. The back-lighting is accomplished with three sets

  12. The vision guidance and image processing of AGV

    Science.gov (United States)

    Feng, Tongqing; Jiao, Bin

    2017-08-01

    Firstly, the principle of AGV vision guidance is introduced and the deviation and deflection angle are measured by image coordinate system. The visual guidance image processing platform is introduced. In view of the fact that the AGV guidance image contains more noise, the image has already been smoothed by a statistical sorting. By using AGV sampling way to obtain image guidance, because the image has the best and different threshold segmentation points. In view of this situation, the method of two-dimensional maximum entropy image segmentation is used to solve the problem. We extract the foreground image in the target band by calculating the contour area method and obtain the centre line with the least square fitting algorithm. With the help of image and physical coordinates, we can obtain the guidance information.

  13. Three dimensional reconstruction of tomographic images of the retina

    International Nuclear Information System (INIS)

    Glittenberg, C.; Zeiler, F.; Falkner, C.; Binder, S.; Povazay, B.; Hermann, B.; Drexler, W.

    2007-01-01

    The development of a new display system for the three-dimensional visualization of tomographic images in ophthalmology. Specifically, a system that can use stacks of B-mode scans from an ultrahigh resolution optical tomography examination to vividly display retinal specimens as three-dimensional objects. Several subroutines were programmed in the rendering and raytracing program Cinema 4D XL 9.102 Studio Bundle (Maxon Computer Inc., Friedrichsburg, Germany), which could process stacks of tomographic scans into three-dimensional objects. Ultrahigh resolution optical coherence tomography examinations were performed on patients with various retinal pathologies and post processed with the subroutines that had been designed. All ultrahigh resolution optical coherence tomographies were performed with a titanium: sapphire based ultra broad bandwidth (160 nm) femtosecond laser system (INTEGRAL, Femtolasers Productions GmbH. Vienna Austria) with an axial resolution of 3 μm. A new three dimensional display system for tomographic images in ophthalmology was developed, which allows a highly vivid display of physiological and pathological structures of the retina. The system also distinguishes itself through its high interactivity and adaptability. This new display system allows the visualization of physiological and pathological structures of the retina in a new way, which will give us new insight into their morphology and development. (author) [de

  14. Design and applications of Computed Industrial Tomographic Imaging System (CITIS)

    International Nuclear Information System (INIS)

    Ramakrishna, G.S.; Umesh Kumar; Datta, S.S.; Rao, S.M.

    1996-01-01

    Computed tomographic imaging is an advanced technique for nondestructive testing (NDT) and examination. For the first time in India a computed aided tomography system has been indigenously developed in BARC for testing industrial components and was successfully demonstrated. The system in addition to Computed Tomography (CT) can also perform Digital Radiography (DR) to serve as a powerful tool for NDT applications. It has wider applications in the fields of nuclear, space and allied fields. The authors have developed a computed industrial tomographic imaging system with Cesium 137 gamma radiation source for nondestructive examination of engineering and industrial specimens. This presentation highlights the design and development of a prototype system and its software for image reconstruction, simulation and display. The paper also describes results obtained with several tests specimens, current development and possibility of using neutrons as well as high energy x-rays in computed tomography. (author)

  15. Tomographic reconstruction of atmospheric volumes from infrared limb-imager measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ungermann, Joern

    2011-08-12

    State-of-the art nadir and limb-sounders, but also in situ measurements, do not offer the capability to highly resolve the atmosphere in all three dimensions. This leaves an observational gap with respect to small-scale structures that arise frequently in the atmosphere and that still lack a quantitative understanding. For instance, filaments and tropopause folds in the upper troposphere and lower stratosphere (UTLS) are crucial for its composition and variability. One way to achieve a highly resolved three-dimensional (3-D) picture of the atmosphere is the tomographic evaluation of limb-imager measurements. This thesis presents a methodology for the tomographic reconstruction of atmospheric constituents. To be able to deal with the large increase of observations and unknowns compared to conventional retrievals, great care is taken to reduce memory consumption and processing time. This method is used to evaluate the performance of two upcoming infrared limb-imager instruments and to prepare their missions. The first examined instrument is the infrared limb-imager on board of PREMIER (Process Exploration through Measurements of Infrared and millimetrewave Emitted Radiation), one of three remaining candidates for ESA's 7th Earth Explorer mission. Scientific goals of PREMIER are, among others, the examination of gravity waves and the quantification of processes controlling atmospheric composition in the UTLS, a region of particular importance for climate change. Simulations based on the performance requirements of this instrument deliver a vertical resolution that is slightly better than its vertical field-of-view (about 0.75 km) and a horizontal resolution of {approx}25km x 70 km. Non-linear end-to-end simulations for various gravity wave patterns demonstrate that the high 3-D resolution of PREMIER considerably extends the range of detectable gravity waves in terms of horizontal and vertical wavelength compared to previous observations. The second examined

  16. Tomographic reconstruction of atmospheric volumes from infrared limb-imager measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ungermann, Joern

    2011-08-12

    State-of-the art nadir and limb-sounders, but also in situ measurements, do not offer the capability to highly resolve the atmosphere in all three dimensions. This leaves an observational gap with respect to small-scale structures that arise frequently in the atmosphere and that still lack a quantitative understanding. For instance, filaments and tropopause folds in the upper troposphere and lower stratosphere (UTLS) are crucial for its composition and variability. One way to achieve a highly resolved three-dimensional (3-D) picture of the atmosphere is the tomographic evaluation of limb-imager measurements. This thesis presents a methodology for the tomographic reconstruction of atmospheric constituents. To be able to deal with the large increase of observations and unknowns compared to conventional retrievals, great care is taken to reduce memory consumption and processing time. This method is used to evaluate the performance of two upcoming infrared limb-imager instruments and to prepare their missions. The first examined instrument is the infrared limb-imager on board of PREMIER (Process Exploration through Measurements of Infrared and millimetrewave Emitted Radiation), one of three remaining candidates for ESA's 7th Earth Explorer mission. Scientific goals of PREMIER are, among others, the examination of gravity waves and the quantification of processes controlling atmospheric composition in the UTLS, a region of particular importance for climate change. Simulations based on the performance requirements of this instrument deliver a vertical resolution that is slightly better than its vertical field-of-view (about 0.75 km) and a horizontal resolution of {approx}25km x 70 km. Non-linear end-to-end simulations for various gravity wave patterns demonstrate that the high 3-D resolution of PREMIER considerably extends the range of detectable gravity waves in terms of horizontal and vertical wavelength compared to previous observations. The second examined instrument

  17. Process and installation for producing tomographic images of the distribution of a radiotracer

    International Nuclear Information System (INIS)

    Fonroget, Jacques; Brunol, Jean.

    1977-01-01

    The invention particularly concerns a process for obtaining tomographic images of an object formed by a radiotracer distributed spacially over three dimensions. This process, using a detection device with an appreciably plane detection surface and at least one collimation orifice provided in a partition between the detection surface and the object, enables tomographic sections to be obtained with an excellent three-dimensional resolution of the images achieved. It is employed to advantage in an installation that includes a detection device or gamma camera on an appreciably plane surface, a device having a series of collimation apertures which may be used in succession, these holes being appreciably distributed over a common plane parallel to the detection surface, and a holder for the object. This holder can be moved in appreciably parallel translation to the common plane. The aim of this invention is, inter alia, to meet two requirements: localization in space and obtaining good contrasts. This aim is achieved by the fact that at least one tomographic image is obtained from a series of intermediate images of the object [fr

  18. Single-Shot, Volumetrically Illuminated, Three-Dimensional, Tomographic Laser-Induced-Fluorescence Imaging in a Gaseous Free Jet

    Science.gov (United States)

    2016-04-28

    Single-shot, volumetrically illuminated, three- dimensional, tomographic laser-induced- fluorescence imaging in a gaseous free jet Benjamin R. Halls...acquisition; (110.6955) Tomographic imaging ; (110.6960) Tomography; (280.2490) Flow diagnostics; (300.2530) Fluorescence , laser-induced...84 (1983). 2. I. van Cruyningen, A. Lozano, and R. K. Hanson, “Quantitative imaging of concentration by planar laser-induced fluorescence ,” Exp

  19. Design and applications of Computed Industrial Tomographic Imaging System (CITIS)

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishna, G S; Kumar, Umesh; Datta, S S [Bhabha Atomic Research Centre, Bombay (India). Isotope Div.

    1994-12-31

    This paper highlights the design and development of a prototype Computed Tomographic (CT) imaging system and its software for image reconstruction, simulation and display. It also describes results obtained with several test specimens including Dhruva reactor uranium fuel assembly and possibility of using neutrons as well as high energy x-rays in computed tomography. 5 refs., 4 figs.

  20. Low-dose computed tomographic imaging in orbital trauma

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, A.; Whitehouse, R.W. (Manchester Univ. (United Kingdom). Dept. of Diagnostic Radiology)

    1993-08-01

    The authors review findings in 75 computed tomographic (CT) examinations of 66 patients with orbital trauma who were imaged using a low-radiation-dose CT technique. Imaging was performed using a dynamic scan mode and exposure factors of 120 kVp and 80 mAs resulting in a skin dose of 11 mGy with an effective dose-equivalent of 0.22 mSv. Image quality was diagnostic in all cases and excellent in 73 examinations. Soft-tissue abnormalities within the orbit including muscle adhesions were well demonstrated both on primary axial and reconstructed multiplanar images. The benefits of multiplanar reconstructions are stressed and the contribution of soft-tissue injuries to symptomatic diplopia examined. (author).

  1. Design of a volume-imaging positron emission tomograph

    International Nuclear Information System (INIS)

    Harrop, R.; Rogers, J.G.; Coombes, G.H.; Wilkinson, N.A.; Pate, B.D.; Morrison, K.S.; Stazyk, M.; Dykstra, C.J.; Barney, J.S.; Atkins, M.S.; Doherty, P.W.; Saylor, D.P.

    1988-11-01

    Progress is reported in several areas of design of a positron volume imaging tomograph. As a means of increasing the volume imaged and the detector packing fraction, a lens system of detector light coupling is considered. A prototype layered scintillator detector demonstrates improved spatial resolution due to a unique Compton rejection capability. The conceptual design of a new mechanism for measuring scattered radiation during emission scans has been tested by Monte Carlo simulation. The problem of how to use effectively the resulting sampled scattered radiation projections is presented and discussed

  2. Tomographic imaging system

    International Nuclear Information System (INIS)

    Hayakawa, T.; Horiba, I.; Kohno, H.; Nakaya, C.; Sekihara, K.; Shiono, H.; Tomura, T.; Yamamoto, S.; Yanaka, S.

    1980-01-01

    A tomographic imaging system comprising: irradiating means for irradating a cross-section of an object under consideration with radiation rays from plural directions; detector means for detecting the radiation rays transmitted through the cross-section of said object to produce an output signal; first memory means for storing the output signal of said detector means; and an image jreconstructing section for performing a convolution integral operation on the contents of said first memory means by means of a first weighting function to reconstruct a three-dimensional image of the cross-section of said object, said image reconstructing section including (I) second memory means for storing a second weighting function, said second weighting function being provided with a predetermined positive and negative (N-1)th order when the output signal of said detector means produced by the irradiation of the cross-section of said object from one of said plural directions is sampled by N points, the value of the (N-1)th order of said second weighting function being an integration of said first weighting function from the (N-1)th order to positive infinity and the value of -(N-1)th order of said second weighting function being an integration of said first weighting function from the -(N-1)th order to negative infinity, (II) control means for successively reading out the contents of said first and second memory means, and (III) operational means for performing multiplying and summing operations on the read-out contents of said first and second memory means, said operational means producing the product of the values fo the (N-1)th and -(N-1)th orders of said second weighting function and a component of the output signal of said detector means relating to the radiation rays free from the absorption thereof by said object

  3. Application of image guidance in pituitary surgery

    Science.gov (United States)

    de Lara, Danielle; Filho, Leo F. S. Ditzel; Prevedello, Daniel M.; Otto, Bradley A.; Carrau, Ricardo L.

    2012-01-01

    Background: Surgical treatment of pituitary pathologies has evolved along the years, adding safety and decreasing morbidity related to the procedure. Advances in the field of radiology, coupled with stereotactic technology and computer modeling, have culminated in the contemporary and widespread use of image guidance systems, as we know them today. Image guidance navigation has become a frequently used technology that provides continuous three-dimensional information for the accurate performance of neurosurgical procedures. We present a discussion about the application of image guidance in pituitary surgeries. Methods: Major indications for image guidance neuronavigation application in pituitary surgery are presented and demonstrated with illustrative cases. Limitations of this technology are also presented. Results: Patients presenting a history of previous transsphenoidal surgeries, anatomical variances of the sphenoid sinus, tumors with a close relation to the internal carotid arteries, and extrasellar tumors are the most important indications for image guidance in pituitary surgeries. The high cost of the equipment, increased time of surgery due to setup time, and registration and the need of specific training for the operating room personnel could be pointed as limitations of this technology. Conclusion: Intraoperative image guidance systems provide real-time images, increasing surgical accuracy and enabling safe, minimally invasive interventions. However, the use of intraoperative navigation is not a replacement for surgical experience and a systematic knowledge of regional anatomy. It must be recognized as a tool by which the neurosurgeon can reduce the risk associated with surgical approach and treatment of pituitary pathologies. PMID:22826819

  4. Imaging MOSS tomographic system for H-1NF

    International Nuclear Information System (INIS)

    Glass, F.; Howard, J.

    1999-01-01

    A tomographic diagnostic utilising the Modulated Optical Solid-State spectrometer (MOSS) is planned for the H-1NF stellarator at the ANU. It is designed to create two-dimensional temperature or velocity maps of a poloidal cross-section of the high temperature plasma of H-1NF. The introduction of the MOSS spectrometers has enabled the development of several diagnostics to be used on the H-1NF stellerator. The MOSS spectrometer allows calculations of the plasma temperature and bulk velocity based on a line-integrated measurement of light emitted from electronic transitions within the plasma. A tomographic system utilising a rotatable multi-view ring apparatus and spatial multiplexing through a MOSS spectrometer is currently being developed. The ring apparatus is placed inside the H-1NF vessel and encircles the plasma. Multiple line-of-sight views collect light through a poloidal cross-section of the plasma and the emitted light is coupled into large core optical fibres. The transmitted light, via the optical fibre bundle, is then imaged through a large aperture MOSS spectrometer and onto another optical fibre array. Each fibre is then fed into a photomultiplier tube for signal detection. Characterisation of the properties of the lithium niobate (LiNbO 3 ) crystal used for modulation in the MOSS spectrometer is being undertaken to account for ray divergence in the imaging system. Tomographic techniques enable the construction of a temperature or velocity map of the poloidal cross-section. Rotating the ring apparatus to a new viewing position for the next pulse of plasma should allow an accurate picture to be built up based on the reproducibility of the plasma pulses. It is expected that initial testing of the system will begin in May when H-1NF begins operations at 0.5 Telsa field strength

  5. Localization of ectopic parathyroid glands using technetium-99m sestamibi imaging: comparison with magnetic resonance and computed tomographic imaging

    International Nuclear Information System (INIS)

    Ishibashi, Masatoshi; Nishida, Hidemi; Hiromatsu Yuji; Kojima, Kazuyuki; Uchida, Masafumi; Hayabuvhi, Naofumi

    1997-01-01

    The aim of the study was to compare the accuracy of technetium-99m sestamibi imaging for localization of ectopic parathyroid glands in patients with hyperparathyroidism with that of magnetic resonance (MR) and computed tomographic (CT) imaging. Eleven patients with primary (n=3) or secondary (n=8) hyperparathyroidism were studied with 99m Tc sestamibi parathyroid imaging CT and MR imaging. Images of the neck were acquired at 10 min and 2-3 after tracer injection. The three patients with primary hyperparathyroidism and five patients with secondary hyperparathyroidism underwent parathyroidectomy. The ectopic glands were confirmed by histopathological examination of the resected specimens. In respect of 20 parathyroid glands in the eight patients explored surgically, the sensitivity and specificity of sestamibi imaging were 70% (14/20) and 88%, respectively, those of CT, 40% (8/20) and 88%, and those of MR imaging, 60% (12/20) and 88%. Of these patients, three had parathyroid adenomas while five had hyperplasia (17 glands). Sestamibi imaging localized eight ectopic parathyroid glands, which were surgically confirmed (six were located in the thymus and two in the mediastinum). In one patient explored surgically, the ectopic gland was located outside the field of the MR coil. Although the remaining three cases of secondary hyperparathyroidism were not confirmed surgically, these patients demonstrated sestamibi uptake in five parathyroid glands, including three ectopic glands. MR imagedemonstrated abnormal parathyroid glands in the same regions as sestamibi imaging. Our data indicate that 99m Tc-sestamibi imaging should be used initially to localize the ectopic parathyroid glands in patients with hyperparathyroidism for anatomical guidance prior to MR or CT imaging

  6. Spiral Computed Tomographic Imaging Related to Computerized Ultrasonographic Images of Carotid Plaque Morphology and Histology

    DEFF Research Database (Denmark)

    Grønholdt, Marie-Louise M.; Wagner, Aase; Wiebe, Britt M.

    2001-01-01

    Echolucency of carotid atherosclerotic plaques, as evaluated by computerized B-mode ultrasonographic images, has been associated with an increased incidence of brain infarcts on cerebral computed tomographic scans. We tested the hypotheses that characterization of carotid plaques on spiral comput...

  7. Self-masking noise subtraction (SMNS) in digital X-ray tomosynthesis for the improvement of tomographic image quality

    International Nuclear Information System (INIS)

    Oh, J.E.; Cho, H.S.; Choi, S.I.; Park, Y.O.; Lee, M.S.; Cho, H.M.; Yang, Y.J.; Je, U.K.; Woo, T.H.; Lee, H.K.

    2011-01-01

    In this paper, we proposed a simple and effective reconstruction algorithm, the so-called self-masking noise subtraction (SMNS), in digital X-ray tomosynthesis to reduce the tomographic blur that is inherent in the conventional tomosynthesis based upon the shift-and-add (SAA) method. Using the SAA and the SMNS algorithms, we investigated the influence of tomographic parameters such as tomographic angle (θ) and angle step (Δθ) on the image quality, measuring the signal-difference-to-noise ratio (SDNR). Our simulation results show that the proposed algorithm seems to be efficient in reducing the tomographic blur and, thus, improving image sharpness. We expect the simulation results to be useful for the optimal design of a digital X-ray tomosynthesis system for our ongoing application of nondestructive testing (NDT).

  8. Tomographical properties of uniformly redundant arrays

    International Nuclear Information System (INIS)

    Cannon, T.M.; Fenimore, E.E.

    1978-01-01

    Recent work in coded aperture imaging has shown that the uniformly redundant array (URA) can image distant planar radioactive sources with no artifacts. The performance of two URA apertures when used in a close-up tomographic imaging system is investigated. It is shown that a URA based on m sequences is superior to one based on quadratic residues. The m sequence array not only produces less obnoxious artifacts in tomographic imaging, but is also more resilient to some described detrimental effects of close-up imaging. It is shown that in spite of these close-up effects, tomographic depth resolution increases as the source is moved closer to the detector

  9. Phase-contrast tomographic imaging using an X-ray interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Momose, A. [Hitachi Ltd, Advanced Research Lab., Saitama (Japan); Takeda, T.; Itai, Y. [Univ. of Tsukuba, Inst. of Clinical Medicine, Ibaraki (Japan); Yoneyama, A. [Hitachi Ltd, Central Resarch Lab., Tokyo (Japan); Hirano, K. [High Energy Accelerator Research Organization, Inst. of Materials Structure Science, Ibaraki (Japan)

    1998-05-01

    Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays. 35 refs.

  10. Phase-contrast tomographic imaging using an X-ray interferometer

    International Nuclear Information System (INIS)

    Momose, A.; Takeda, T.; Itai, Y.; Yoneyama, A.; Hirano, K.

    1998-01-01

    Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays

  11. Usefulness of tomographic phase image in ventricular conduction abnormalities

    International Nuclear Information System (INIS)

    Sakurai, Mitsuru; Watanabe, Yoshihiko; Kondo, Takeshi

    1985-01-01

    In order to evaluate three-dimensional phase changes in ventricular conduction abnormalities, tomographic phase images were constructed in 7 normal subjects, 12 patients with ventricular pacing, 21 patients with bundle branch block and 12 patients with Wolff-Parkinson-White syndrome. Eight to 12 slices of the short-axis ventricular tomographic phase image (TPI) were derived using a 7-pinhole collimator, and compared with planar phase images (PPIs) in left anterior oblique (LAO) and right anterior oblique (RAO) projections. TPIs were excellent for observing biventricular phase changes in the long-axis direction. In 6 cases of complete right bundle branch block with left axis deviation (beyond -30 0 ), the phase delay in the left ventricular anterior wall was recognized in 5 cases by TPI, although it was difficult to be detected by PPIs. The site of the pacing electrode was identified by TPI in 11 out of 12 cases, compared to 8 cases by PPIs in LAO and RAO projections. The site of the accessory pathway in Wolff-Parkinson-White syndrome was detected in the basal slice of TPIs in 10 out of 12 cases, compared to 8 cases by PPI in the LAO projection. Therefore, it is obvious that TPIs offer more valid information than PPIs. In conclusion, TPI is useful for investigation of ventricular conduction abnormalities. (author)

  12. Tomographic Small-Animal Imaging Using a High-Resolution Semiconductor Camera

    Science.gov (United States)

    Kastis, GA; Wu, MC; Balzer, SJ; Wilson, DW; Furenlid, LR; Stevenson, G; Barber, HB; Barrett, HH; Woolfenden, JM; Kelly, P; Appleby, M

    2015-01-01

    We have developed a high-resolution, compact semiconductor camera for nuclear medicine applications. The modular unit has been used to obtain tomographic images of phantoms and mice. The system consists of a 64 x 64 CdZnTe detector array and a parallel-hole tungsten collimator mounted inside a 17 cm x 5.3 cm x 3.7 cm tungsten-aluminum housing. The detector is a 2.5 cm x 2.5 cm x 0.15 cm slab of CdZnTe connected to a 64 x 64 multiplexer readout via indium-bump bonding. The collimator is 7 mm thick, with a 0.38 mm pitch that matches the detector pixel pitch. We obtained a series of projections by rotating the object in front of the camera. The axis of rotation was vertical and about 1.5 cm away from the collimator face. Mouse holders were made out of acrylic plastic tubing to facilitate rotation and the administration of gas anesthetic. Acquisition times were varied from 60 sec to 90 sec per image for a total of 60 projections at an equal spacing of 6 degrees between projections. We present tomographic images of a line phantom and mouse bone scan and assess the properties of the system. The reconstructed images demonstrate spatial resolution on the order of 1–2 mm. PMID:26568676

  13. An original emission tomograph for in vivo brain imaging of small animals

    International Nuclear Information System (INIS)

    Ochoa, A.V.; Ploux, L.; Mastrippolito, R.

    1996-01-01

    The principle of a new tomograph TOHR dedicated for small volume analysis with very high resolution is presented in this paper. We use uncorrelated multi-photons (X or gamma rays) radioisotopes and a large solid angle focusing collimator to make tomographic imaging without reconstruction algorithm. With this original device, detection efficiency and resolution are independent and submillimetric resolution can be achieved. A feasibility study shows that, made achieve the predicted performances of TOHR. We discuss its potential in rat brain tomography by simulating a realistic neuropharmacological experiment using a 1.4 mm resolution prototype of TOHR under development

  14. Computed tomography guidance for skeletal biopsy

    International Nuclear Information System (INIS)

    Frager, D.H.; Goldman, M.J.; Elkin, C.M.; Cynamon, J.; Leeds, N.E.; Seimon, L.P.; Habermann, E.T.; Schreiber, K.; Freeman, L.M.

    1987-01-01

    Computed tomographic (CT) guided biopsy and abscess drainage of multiple organ systems have been well described. Reports of spinal and skeletal applications have been less common. This study describes the use of CT guidance in the biopsy of various skeletal lesions in 46 patients. Forty-one patients had skinny needle aspirations (18 or 22 gauge) and 23 patients had trephine core biopsies. Sites of the lesions included: thoracic spine - 15 patients, lumbosacral spine - 17 patients, bony pelvis - 6 patients, rib - 2 patients, and long bones - 6 patients. Fast scanners capable of rapid image reconstruction have overcome many constraints. With CT guidance, the physician who performs the procedure receives virtually no ionizing radiation. The exact location of the needle tip is accurately visualized in relation to the lesion being biopsied and to the vital organs. (orig.)

  15. Advances in tomographic PIV

    NARCIS (Netherlands)

    Novara, M.

    2013-01-01

    This research deals with advanced developments in 3D particle image velocimetry based on the tomographic PIV technique (Tomo-PIV). The latter is a relatively recent measurement technique introduced by Elsinga et al. in 2005, which is based on the tomographic reconstruction of particle tracers in

  16. Hybrid Photoacoustic/Ultrasound Tomograph for Real-Time Finger Imaging.

    Science.gov (United States)

    Oeri, Milan; Bost, Wolfgang; Sénégond, Nicolas; Tretbar, Steffen; Fournelle, Marc

    2017-10-01

    We report a target-enclosing, hybrid tomograph with a total of 768 elements based on capacitive micromachined ultrasound transducer technology and providing fast, high-resolution 2-D/3-D photoacoustic and ultrasound tomography tailored to finger imaging. A freely programmable ultrasound beamforming platform sampling data at 80 MHz was developed to realize plane wave transmission under multiple angles. A multiplexing unit enables the connection and control of a large number of elements. Fast image reconstruction is provided by GPU processing. The tomograph is composed of four independent and fully automated movable arc-shaped transducers, allowing imaging of all three finger joints. The system benefits from photoacoustics, yielding high optical contrast and enabling visualization of finger vascularization, and ultrasound provides morphologic information on joints and surrounding tissue. A diode-pumped, Q-switched Nd:YAG laser and an optical parametric oscillator are used to broaden the spectrum of emitted wavelengths to provide multispectral imaging. Custom-made optical fiber bundles enable illumination of the region of interest in the plane of acoustic detection. Precision in positioning of the probe in motion is ensured by use of a motor-driven guide slide. The current position of the probe is encoded by the stage and used to relate ultrasound and photoacoustic signals to the corresponding region of interest of the suspicious finger joint. The system is characterized in phantoms and a healthy human finger in vivo. The results obtained promise to provide new opportunities in finger diagnostics and establish photoacoustic/ultrasound-tomography in medical routine. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  17. Image registration assessment in radiotherapy image guidance based on control chart monitoring.

    Science.gov (United States)

    Xia, Wenyao; Breen, Stephen L

    2018-04-01

    Image guidance with cone beam computed tomography in radiotherapy can guarantee the precision and accuracy of patient positioning prior to treatment delivery. During the image guidance process, operators need to take great effort to evaluate the image guidance quality before correcting a patient's position. This work proposes an image registration assessment method based on control chart monitoring to reduce the effort taken by the operator. According to the control chart plotted by daily registration scores of each patient, the proposed method can quickly detect both alignment errors and image quality inconsistency. Therefore, the proposed method can provide a clear guideline for the operators to identify unacceptable image quality and unacceptable image registration with minimal effort. Experimental results demonstrate that by using control charts from a clinical database of 10 patients undergoing prostate radiotherapy, the proposed method can quickly identify out-of-control signals and find special cause of out-of-control registration events.

  18. Optical Coherence Tomographic Imaging and Delivery for Surgical Guidance

    National Research Council Canada - National Science Library

    Fujimoto, James G

    2004-01-01

    .... OCT can thus function as a type of "optical biopsy," enabling imaging of tissue with resolution approaching conventional biopsy and histopathology, but without the need to remove and process specimens...

  19. Gas microstrip detectors for X-ray tomographic flow imaging

    CERN Document Server

    Key, M J; Luggar, R D; Kundu, A

    2003-01-01

    A investigation into the suitability of gas microstrip detector technology for a high-speed industrial X-ray tomography system is reported. X-ray energies in the region 20-30 keV are well suited to the application, which involves imaging two-dimensional slices through gas/liquid multiphase pipeline flows for quantitative component fraction measurement. Stable operation over a period representing several hundred individual tomographic scans at gas gains of 500 is demonstrated using a Penning gas mixture of krypton/propylene.

  20. 3D Tomographic Image Reconstruction using CUDA C

    International Nuclear Information System (INIS)

    Dominguez, J. S.; Assis, J. T.; Oliveira, L. F. de

    2011-01-01

    This paper presents the study and implementation of a software for three dimensional reconstruction of images obtained with a tomographic system using the capabilities of Graphic Processing Units(GPU). The reconstruction by filtered back-projection method was developed using the CUDA C, for maximum utilization of the processing capabilities of GPUs to solve computational problems with large computational cost and highly parallelizable. It was discussed the potential of GPUs and shown its advantages to solving this kind of problems. The results in terms of runtime will be compared with non-parallelized implementations and must show a great reduction of processing time. (Author)

  1. Image guidance improves localization of sonographically occult colorectal liver metastases

    Science.gov (United States)

    Leung, Universe; Simpson, Amber L.; Adams, Lauryn B.; Jarnagin, William R.; Miga, Michael I.; Kingham, T. Peter

    2015-03-01

    Assessing the therapeutic benefit of surgical navigation systems is a challenging problem in image-guided surgery. The exact clinical indications for patients that may benefit from these systems is not always clear, particularly for abdominal surgery where image-guidance systems have failed to take hold in the same way as orthopedic and neurosurgical applications. We report interim analysis of a prospective clinical trial for localizing small colorectal liver metastases using the Explorer system (Path Finder Technologies, Nashville, TN). Colorectal liver metastases are small lesions that can be difficult to identify with conventional intraoperative ultrasound due to echogeneity changes in the liver as a result of chemotherapy and other preoperative treatments. Interim analysis with eighteen patients shows that 9 of 15 (60%) of these occult lesions could be detected with image guidance. Image guidance changed intraoperative management in 3 (17%) cases. These results suggest that image guidance is a promising tool for localization of small occult liver metastases and that the indications for image-guided surgery are expanding.

  2. Ectomography - a tomographic method for gamma camera imaging

    International Nuclear Information System (INIS)

    Dale, S.; Edholm, P.E.; Hellstroem, L.G.; Larsson, S.

    1985-01-01

    In computerised gamma camera imaging the projections are readily obtained in digital form, and the number of picture elements may be relatively few. This condition makes emission techniques suitable for ectomography - a tomographic technique for directly visualising arbitrary sections of the human body. The camera rotates around the patient to acquire different projections in a way similar to SPECT. This method differs from SPECT, however, in that the camera is placed at an angle to the rotational axis, and receives two-dimensional, rather than one-dimensional, projections. Images of body sections are reconstructed by digital filtration and combination of the acquired projections. The main advantages of ectomography - a high and uniform resolution, a low and uniform attenuation and a high signal-to-noise ratio - are obtained when imaging sections close and parallel to a body surface. The filtration eliminates signals representing details outside the section and gives the section a certain thickness. Ectomographic transverse images of a line source and of a human brain have been reconstructed. Details within the sections are correctly visualised and details outside are effectively eliminated. For comparison, the same sections have been imaged with SPECT. (author)

  3. The application of real-time, non-destructive electrical tomographic imaging to heritage conservation

    OpenAIRE

    Ogilvy, Richard

    2008-01-01

    Significant advances have been made in recent times with the non-invasive electrical tomographic imaging of the shallow subsurface. These emerging technologies are analogous to magnetic resonance imaging (MRI) or CT scans used in medical physics. Electrical Resistivity Tomography (ERT) is increasingly used to underpin studies in waste management, contaminated land characterisation and remediation, monitoring groundwater resources and the monitoring of geohazards or safety-critical plant. Ther...

  4. Tomographic imaging of matter using primary and secondary X-and gamma-radiation

    International Nuclear Information System (INIS)

    Holloway, I.E.

    1991-04-01

    Gamma rays may interact with matter by a variety of processes, many of which give rise to secondary radiations. This thesis examines the possibility of performing tomographic imaging by means of these secondary photons using low-cost apparatus. The techniques are compared with each other and with transmission tomography, which plays such an important role in modern diagnostic imaging. The progress of industrial tomography is reviewed as are techniques of investigation using gamma ray scattering in both industry and medicine. Some new applications of a simple gamma ray computerized tomography (CT) scanner have been performed. A method of determining the spatial distribution of pure beta emitters in matter by performing tomographic imaging using the bremsstrahlung radiation produced by the beta particles has been demonstrated. This technique has been shown to permit imaging at depths in material greatly exceeding the range of beta particles in matter. All the imaging techniques using secondary radiation have displayed two principal limitations: long scanning times and poor quantitative accuracy. The low scanning rate results from the small number of secondary photons that are detected. The major contributing factors to poor accuracy are attenuation and the noise produced by unwanted in-scattering. The possible applications for secondary photon imaging have been briefly outlined and some suggestions for future work are included. Although techniques based upon imaging using secondary radiation will not be able to compete with transmission CT in the vast majority of applications, they may prove valuable in a range of specialised fields. (author)

  5. Lamb-Wave-Based Tomographic Imaging Techniques for Hole-Edge Corrosion Monitoring in Plate Structures

    Directory of Open Access Journals (Sweden)

    Dengjiang Wang

    2016-11-01

    Full Text Available This study presents a novel monitoring method for hole-edge corrosion damage in plate structures based on Lamb wave tomographic imaging techniques. An experimental procedure with a cross-hole layout using 16 piezoelectric transducers (PZTs was designed. The A0 mode of the Lamb wave was selected, which is sensitive to thickness-loss damage. The iterative algebraic reconstruction technique (ART method was used to locate and quantify the corrosion damage at the edge of the hole. Hydrofluoric acid with a concentration of 20% was used to corrode the specimen artificially. To estimate the effectiveness of the proposed method, the real corrosion damage was compared with the predicted corrosion damage based on the tomographic method. The results show that the Lamb-wave-based tomographic method can be used to monitor the hole-edge corrosion damage accurately.

  6. Non-rigid registration of tomographic images with Fourier transforms

    International Nuclear Information System (INIS)

    Osorio, Ar; Isoardi, Ra; Mato, G

    2007-01-01

    Spatial image registration of deformable body parts such as thorax and abdomen has important medical applications, but at the same time, it represents an important computational challenge. In this work we propose an automatic algorithm to perform non-rigid registration of tomographic images using a non-rigid model based on Fourier transforms. As a measure of similarity, we use the correlation coefficient, finding that the optimal order of the transformation is n = 3 (36 parameters). We apply this method to a digital phantom and to 7 pairs of patient images corresponding to clinical CT scans. The preliminary results indicate a fairly good agreement according to medical experts, with an average registration error of 2 mm for the case of clinical images. For 2D images (dimensions 512x512), the average running time for the algorithm is 15 seconds using a standard personal computer. Summarizing, we find that intra-modality registration of the abdomen can be achieved with acceptable accuracy for slight deformations and can be extended to 3D with a reasonable execution time

  7. On a novel low cost high accuracy experimental setup for tomographic particle image velocimetry

    International Nuclear Information System (INIS)

    Discetti, Stefano; Ianiro, Andrea; Astarita, Tommaso; Cardone, Gennaro

    2013-01-01

    This work deals with the critical aspects related to cost reduction of a Tomo PIV setup and to the bias errors introduced in the velocity measurements by the coherent motion of the ghost particles. The proposed solution consists of using two independent imaging systems composed of three (or more) low speed single frame cameras, which can be up to ten times cheaper than double shutter cameras with the same image quality. Each imaging system is used to reconstruct a particle distribution in the same measurement region, relative to the first and the second exposure, respectively. The reconstructed volumes are then interrogated by cross-correlation in order to obtain the measured velocity field, as in the standard tomographic PIV implementation. Moreover, differently from tomographic PIV, the ghost particle distributions of the two exposures are uncorrelated, since their spatial distribution is camera orientation dependent. For this reason, the proposed solution promises more accurate results, without the bias effect of the coherent ghost particles motion. Guidelines for the implementation and the application of the present method are proposed. The performances are assessed with a parametric study on synthetic experiments. The proposed low cost system produces a much lower modulation with respect to an equivalent three-camera system. Furthermore, the potential accuracy improvement using the Motion Tracking Enhanced MART (Novara et al 2010 Meas. Sci. Technol. 21 035401) is much higher than in the case of the standard implementation of tomographic PIV. (paper)

  8. Connections model for tomographic images reconstruction; Modelo conexionista para reconstrucao de imagens tomograficas

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, R.G.S.; Pela, C.A.; Roque, S.F. A.C. [Departamento de Fisica e Matematica (FFCLRP) USP. Av. Bandeirantes, 3900- 14040- 901- Ribeirao Preto, Sao Paulo (Brazil)

    1998-12-31

    This paper shows an artificial neural network with an adequately topology for tomographic image reconstruction. The associated error function is derived and the learning algorithm is make. The simulated results are presented and demonstrate the existence of a generalized solution for nets with linear activation function. (Author)

  9. GPU acceleration towards real-time image reconstruction in 3D tomographic diffractive microscopy

    Science.gov (United States)

    Bailleul, J.; Simon, B.; Debailleul, M.; Liu, H.; Haeberlé, O.

    2012-06-01

    Phase microscopy techniques regained interest in allowing for the observation of unprepared specimens with excellent temporal resolution. Tomographic diffractive microscopy is an extension of holographic microscopy which permits 3D observations with a finer resolution than incoherent light microscopes. Specimens are imaged by a series of 2D holograms: their accumulation progressively fills the range of frequencies of the specimen in Fourier space. A 3D inverse FFT eventually provides a spatial image of the specimen. Consequently, acquisition then reconstruction are mandatory to produce an image that could prelude real-time control of the observed specimen. The MIPS Laboratory has built a tomographic diffractive microscope with an unsurpassed 130nm resolution but a low imaging speed - no less than one minute. Afterwards, a high-end PC reconstructs the 3D image in 20 seconds. We now expect an interactive system providing preview images during the acquisition for monitoring purposes. We first present a prototype implementing this solution on CPU: acquisition and reconstruction are tied in a producer-consumer scheme, sharing common data into CPU memory. Then we present a prototype dispatching some reconstruction tasks to GPU in order to take advantage of SIMDparallelization for FFT and higher bandwidth for filtering operations. The CPU scheme takes 6 seconds for a 3D image update while the GPU scheme can go down to 2 or > 1 seconds depending on the GPU class. This opens opportunities for 4D imaging of living organisms or crystallization processes. We also consider the relevance of GPU for 3D image interaction in our specific conditions.

  10. 3D tomographic imaging with the γ-eye planar scintigraphic gamma camera

    Science.gov (United States)

    Tunnicliffe, H.; Georgiou, M.; Loudos, G. K.; Simcox, A.; Tsoumpas, C.

    2017-11-01

    γ-eye is a desktop planar scintigraphic gamma camera (100 mm × 50 mm field of view) designed by BET Solutions as an affordable tool for dynamic, whole body, small-animal imaging. This investigation tests the viability of using γ-eye for the collection of tomographic data for 3D SPECT reconstruction. Two software packages, QSPECT and STIR (software for tomographic image reconstruction), have been compared. Reconstructions have been performed using QSPECT’s implementation of the OSEM algorithm and STIR’s OSMAPOSL (Ordered Subset Maximum A Posteriori One Step Late) and OSSPS (Ordered Subsets Separable Paraboloidal Surrogate) algorithms. Reconstructed images of phantom and mouse data have been assessed in terms of spatial resolution, sensitivity to varying activity levels and uniformity. The effect of varying the number of iterations, the voxel size (1.25 mm default voxel size reduced to 0.625 mm and 0.3125 mm), the point spread function correction and the weight of prior terms were explored. While QSPECT demonstrated faster reconstructions, STIR outperformed it in terms of resolution (as low as 1 mm versus 3 mm), particularly when smaller voxel sizes were used, and in terms of uniformity, particularly when prior terms were used. Little difference in terms of sensitivity was seen throughout.

  11. A tensor-based dictionary learning approach to tomographic image reconstruction

    DEFF Research Database (Denmark)

    Soltani, Sara; Kilmer, Misha E.; Hansen, Per Christian

    2016-01-01

    We consider tomographic reconstruction using priors in the form of a dictionary learned from training images. The reconstruction has two stages: first we construct a tensor dictionary prior from our training data, and then we pose the reconstruction problem in terms of recovering the expansion...... coefficients in that dictionary. Our approach differs from past approaches in that (a) we use a third-order tensor representation for our images and (b) we recast the reconstruction problem using the tensor formulation. The dictionary learning problem is presented as a non-negative tensor factorization problem...... with sparsity constraints. The reconstruction problem is formulated in a convex optimization framework by looking for a solution with a sparse representation in the tensor dictionary. Numerical results show that our tensor formulation leads to very sparse representations of both the training images...

  12. Formation of tomographic images with neutrons

    International Nuclear Information System (INIS)

    Duarte, A.; Tenreiro, C; Valencia, J; Steinman, G.; Henriquez, C

    2000-01-01

    The possibility of having a non-destructive method of analysis for archaeological and paleontological samples is of interest. A special group of fossil samples has come to our attention, which because of their value should be preserved and, therefore, the availability of an indirect, non-destructive, non contaminating analytical technique is important. The strong absorption of usual kinds of radiation by a fossilized sample restricts the application of conventional methods of analysis. A type of radiation that is not completely attenuated by thick samples, in sizes that are typical in paleontology, is necessary. Neutrons may be considered as an ideal non-invasive probe with the possibility of developing a technique for the formation and analysis of images. A technique has been developed for the spatial reconstruction of the contents of a fossilized sample (tomography) with neutrons, without touching or altering the sample in any way. The neutron beam was extracted from the RECH-1 reactor belonging to the CCHEN, La Reina. The tomographic images of the contents of a fossilized egg are presented for the first time and represent views or cuts of the content as well as a set that permits the three dimensional reconstruction of the inside of the object and its subsequent animation in graphic format. This project developed a technique for taking neutron radiographs of this kind of sample including the numerical algorithms and the treatment and formation of the images (CW)

  13. Effect of Shot Noise on Simultaneous Sensing in Frequency Division Multiplexed Diffuse Optical Tomographic Imaging Process.

    Science.gov (United States)

    Jang, Hansol; Lim, Gukbin; Hong, Keum-Shik; Cho, Jaedu; Gulsen, Gultekin; Kim, Chang-Seok

    2017-11-28

    Diffuse optical tomography (DOT) has been studied for use in the detection of breast cancer, cerebral oxygenation, and cognitive brain signals. As optical imaging studies have increased significantly, acquiring imaging data in real time has become increasingly important. We have developed frequency-division multiplexing (FDM) DOT systems to analyze their performance with respect to acquisition time and imaging quality, in comparison with the conventional time-division multiplexing (TDM) DOT. A large tomographic area of a cylindrical phantom 60 mm in diameter could be successfully reconstructed using both TDM DOT and FDM DOT systems. In our experiment with 6 source-detector (S-D) pairs, the TDM DOT and FDM DOT systems required 6.18 and 1 s, respectively, to obtain a single tomographic data set. While the absorption coefficient of the reconstruction image was underestimated in the case of the FDM DOT, we experimentally confirmed that the abnormal region can be clearly distinguished from the background phantom using both methods.

  14. Effect of Shot Noise on Simultaneous Sensing in Frequency Division Multiplexed Diffuse Optical Tomographic Imaging Process

    Directory of Open Access Journals (Sweden)

    Hansol Jang

    2017-11-01

    Full Text Available Diffuse optical tomography (DOT has been studied for use in the detection of breast cancer, cerebral oxygenation, and cognitive brain signals. As optical imaging studies have increased significantly, acquiring imaging data in real time has become increasingly important. We have developed frequency-division multiplexing (FDM DOT systems to analyze their performance with respect to acquisition time and imaging quality, in comparison with the conventional time-division multiplexing (TDM DOT. A large tomographic area of a cylindrical phantom 60 mm in diameter could be successfully reconstructed using both TDM DOT and FDM DOT systems. In our experiment with 6 source-detector (S-D pairs, the TDM DOT and FDM DOT systems required 6.18 and 1 s, respectively, to obtain a single tomographic data set. While the absorption coefficient of the reconstruction image was underestimated in the case of the FDM DOT, we experimentally confirmed that the abnormal region can be clearly distinguished from the background phantom using both methods.

  15. Correlation of computed tomographic and magnetic resonance imaging findings in cerebral infartion

    International Nuclear Information System (INIS)

    Komatsubara, Chizuko; Chuda, Moriyoshi; Taka, Toshihiko

    1989-01-01

    We evaluated neurological findings in 75 patients of cerebral infarction, and correlated computed tomographic (CT) and magnetic resonance imaging (MRI) findings. MRI was found to have the advantage when the lesion were multiple, or in the posterior fossa. MRI demonstrates the anatomical details, and lacks the bony artifact, so it is an excellent method for identification of cerebral infarction. (author)

  16. A novel clinical multimodal multiphoton tomograph for AF, SHG, CARS imaging, and FLIM

    Science.gov (United States)

    Weinigel, Martin; Breunig, Hans Georg; König, Karsten

    2014-02-01

    We report on a flexible nonlinear medical tomograph with multiple miniaturized detectors for simultaneous acquisition of two-photon autofluorescence (AF), second harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) images. The simultaneous visualization of the distribution of endogenous fluorophores NAD(P)H, melanin and elastin, SHG-active collagen and as well as non-fluorescent lipids within human skin in vivo is possible. Furthermore, fluorescence lifetime images (FLIM) can be generated using time-correlated single photon counting.

  17. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are given of a tomographic scanning apparatus, with particular reference to a multiplexer slip ring means for receiving output from the detectors and enabling interfeed to the image reconstruction station. (U.K.)

  18. Longitudinal and transverse digital image reconstruction with a tomographic scanner

    International Nuclear Information System (INIS)

    Pickens, D.R.; Price, R.R.; Erickson, J.J.; Patton, J.A.; Partain, C.L.; Rollo, F.D.

    1981-01-01

    A Siemens Gammasonics PHO/CON-192 Multiplane Imager is interfaced to a digital computer for the purpose of performing tomographic reconstructions from the data collected during a single scan. Data from the two moving gamma cameras as well as camera position information are sent to the computer by an interface designed in the authors' laboratory. Backprojection reconstruction is implemented by the computer. Longitudinal images in whole-body format as well as smaller formats are reconstructed for up to six planes simultaneously from the list mode data. Transverse reconstructions are demonstrated for 201 T1 myocardial scans. Post-reconstruction deconvolution processing to remove the blur artifact (characteristic of focal plane tomography) is applied to a multiplane phantom. Digital data acquisition of data and reconstruction of images are practical, and can extend the usefulness of the machine when compared with the film output (author)

  19. Re-evaluation of Magnetic Resonance and Computerised Tomographic Imaging in Neuro-Ophthalmic Patients in an Academic Centre

    NARCIS (Netherlands)

    Koekoek, Clarence G. J.; Meiners, Linda C.; Pott, Jan Willem R.

    The aim of the study is to report the frequency of missed diagnoses on magnetic resonance and computerised tomographic imaging in neuro-ophthalmic patients who were referred to an academic ophthalmology department, with apparent normal imaging. The authors included all neuro-ophthalmic patients,

  20. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    A tomographic array with the following characteristics is described. An X-ray screen serving as detector is placed before a photomultiplier tube which itself is placed in front of a television camera connected to a set of image processors. The detector is concave towards the source and is replacable. Different images of the object are obtained simultaneously. Optical fibers and lenses are used for transmission within the system

  1. Evaluation of Image-Guidance Strategies in the Treatment of Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Lee, Choonik; Langen, Katja M.; Zeidan, Omar A.; Manon, Rafael R.; Willoughby, Twyla R.; Meeks, Sanford L.

    2008-01-01

    Purpose: To compare different image-guidance strategies in the alignment of prostate cancer patients. Using data from patients treated using daily image guidance, the remaining setup errors for several different strategies were retrospectively calculated. Methods and Materials: The alignment data from 74 patients treated with helical tomotherapy were analyzed, resulting in a data set of 2,252 fractions during which a megavoltage computed tomography image was used for image guidance with intraprostatic metallic fiducials. Given the daily positional adjustments, a variety of protocols, differing in imaging frequency and method, were retrospectively studied. The residual setup errors were determined for each protocol. Results: As expected, the systematic errors were effectively reduced with imaging. However, the random errors were unaffected. Even when image guidance was performed every other day with a running mean of the previous displacements, residual setup errors >5 mm occurred in 24% of all fractions. This frequency increased to about 40% if setup errors >3 mm were scored. Conclusion: Setup errors increased with decreasing frequency of image guidance. However, residual errors were still significant at the 5-mm level, even with imaging was performed every other day. This suggests that localizations must be performed daily in the set up of prostate cancer patients during a course of external beam radiotherapy

  2. Arbitrary layer tomographic method and apparatus

    International Nuclear Information System (INIS)

    Kato, H.; Ishida, M.

    1984-01-01

    Many two-dimensional X-ray projection distribution images obtained by exposing an object to X-rays in various directions are once stored in positions different from one another in a stimulable phosphor sheet or respectively in many stimulable phosphor sheets. The stimulable phosphor sheet or sheets are then scanned with stimulating rays, and the light emitted thereby from the stimulable phosphor sheet or sheets is photoelectrically read out to obtain electric signals representing the X-ray projection distribution images. The electric signals are processed to obtain a tomographic image of an arbitrary tomographic layer of the object

  3. An efficient reconstruction algorithm for differential phase-contrast tomographic images from a limited number of views

    International Nuclear Information System (INIS)

    Sunaguchi, Naoki; Yuasa, Tetsuya; Gupta, Rajiv; Ando, Masami

    2015-01-01

    The main focus of this paper is reconstruction of tomographic phase-contrast image from a set of projections. We propose an efficient reconstruction algorithm for differential phase-contrast computed tomography that can considerably reduce the number of projections required for reconstruction. The key result underlying this research is a projection theorem that states that the second derivative of the projection set is linearly related to the Laplacian of the tomographic image. The proposed algorithm first reconstructs the Laplacian image of the phase-shift distribution from the second-derivative of the projections using total variation regularization. The second step is to obtain the phase-shift distribution by solving a Poisson equation whose source is the Laplacian image previously reconstructed under the Dirichlet condition. We demonstrate the efficacy of this algorithm using both synthetically generated simulation data and projection data acquired experimentally at a synchrotron. The experimental phase data were acquired from a human coronary artery specimen using dark-field-imaging optics pioneered by our group. Our results demonstrate that the proposed algorithm can reduce the number of projections to approximately 33% as compared with the conventional filtered backprojection method, without any detrimental effect on the image quality

  4. Voxel-based model construction from colored tomographic images

    International Nuclear Information System (INIS)

    Loureiro, Eduardo Cesar de Miranda

    2002-07-01

    This work presents a new approach in the construction of voxel-based phantoms that was implemented to simplify the segmentation process of organs and tissues reducing the time used in this procedure. The segmentation process is performed by painting tomographic images and attributing a different color for each organ or tissue. A voxel-based head and neck phantom was built using this new approach. The way as the data are stored allows an increasing in the performance of the radiation transport code. The program that calculates the radiation transport also works with image files. This capability allows image reconstruction showing isodose areas, under several points of view, increasing the information to the user. Virtual X-ray photographs can also be obtained allowing that studies could be accomplished looking for the radiographic techniques optimization assessing, at the same time, the doses in organs and tissues. The accuracy of the program here presented, called MCvoxEL, that implements this new approach, was tested by comparison to results from two modern and well-supported Monte Carlo codes. Dose conversion factors for parallel X-ray exposure were also calculated. (author)

  5. Compact Positron Tomograph for Prostate Imaging

    National Research Council Canada - National Science Library

    Huber, Jennifer

    2004-01-01

    The goal of this project is to construct a functioning compact positron tomograph, whose geometry is optimized for detecting prostate tumors with molecular tracers such as 11Ccholine (carbon-11 choline...

  6. Compact Positron Tomograph for Prostate Imaging

    National Research Council Canada - National Science Library

    Huber, Jennifer S

    2005-01-01

    The goal of this project is to construct a functioning compact positron tomograph, whose geometry is optimized for detecting prostate tumors with molecular tracers such as 11Ccholine (carbon-11 choline...

  7. Tomographic method and apparatus

    International Nuclear Information System (INIS)

    Moore, R.M.

    1981-01-01

    A tomographic x-ray machine has a camera and film-plane section which move about a primary axis for imaging a selected cross-section of an anatomical member onto the film. A ''scout image'' of the member is taken at right angles to the plane of the desired cross-section to indicate the cross-section's angle with respect to the primary axis. The film plane is then located at the same angle with respect to a film cassette axis as the selected cross-section makes with the primary axis. The film plane and the cross-section are then maintained in parallel planes throughout motion of the camera and film plane during tomographic radiography. (author)

  8. Tomographic Imaging of the Seismic Structure Beneath the East Anatolian Plateau, Eastern Turkey

    Science.gov (United States)

    Gökalp, Hüseyin

    2012-10-01

    The high level of seismic activity in eastern Turkey is thought to be mainly associated with the continuing collision of the Arabian and Eurasian tectonic plates. The determination of a detailed three-dimensional (3D) structure is crucial for a better understanding of this on-going collision or subduction process; therefore, a body wave tomographic inversion technique was performed on the region. The tomographic inversion used high quality arrival times from earthquakes occurring in the region from 1999 to 2001 recorded by a temporary 29 station broadband IRIS-PASSCAL array operated by research groups from the Universities of Boğaziçi (Turkey) and Cornell (USA). The data was inverted and consisted of 3,114 P- and 2,298 S-wave arrival times from 252 local events with magnitudes ( M D) ranging from 2.5 to 4.8. The stability and resolution of the results were qualitatively assessed by two synthetic tests: a spike test and checkerboard resolution test and it was found that the models were well resolved for most parts of the imaged domain. The tomographic inversion results reveal significant lateral heterogeneities in the study area to a depth of ~20 km. The P- and S-wave velocity models are consistent with each other and provide evidence for marked heterogeneities in the upper crustal structure beneath eastern Turkey. One of the most important features in the acquired tomographic images is the high velocity anomalies, which are generally parallel to the main tectonic units in the region, existing at shallow depths. This may relate to the existence of ophiolitic units at shallow depths. The other feature is that low velocities are widely dispersed through the 3D structure beneath the region at deeper crustal depths. This feature can be an indicator of the mantle upwelling or support the hypothesis that the Anatolian Plateau is underlain by a partially molten uppermost mantle.

  9. Advances in imaging for oncology guidance

    International Nuclear Information System (INIS)

    Amies, Christopher J.

    2008-01-01

    Over the last 30 years major improvements in medical imaging have played a significant role to help advance the management of oncology diseases. These advances have covered the continuum of care from screening, diagnosis, staging, treatment planning and intervention. More recently image guided radiation therapy (IGRT) has placed sophisticated imaging closer to the treatment event. The opportunity to improve care seems obvious; however the clinical benefits of IGRT are at present not easily proven and yet contribute to the complexity of treatment and the rising costs of care. It is proposed that this is in part due to the present immaturity of IGRT technology development, which is predominantly determined by the challenge of achieving precise delivery of radiation in one or many episodes (fractions) for very different diseases. There is no single type or mode of imaging that will be suitable to address all radiotherapy guidance challenges whether defined by the general criteria identified for a specific disease or the unique characteristics encountered with an individual patient. Finally the wide adoption of this or any medical technology general requires the attainment of a sufficient degree of safety and efficiency. I present the challenges faced by industry as well as select interesting technology based solutions and concepts that may help advance the field of oncology guidance

  10. Gynecologic radiation therapy. Novel approaches to image-guidance and management

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Akila N. [Harvard Medical School, Boston, MA (United States). Dept. of Radiation Oncology; Kirisits, Christian; Poetter, Richard (eds.) [Vienna General Hospital Medical Univ. (Austria). Dept. of Radiotherapy; Erickson, Beth E. [Medical College of Wisconsin Clinics Froedtert Hospital, Milwaukee, WI (United States). Dept. of Radiation Oncology

    2011-07-01

    Recent advances in the treatment of gynecologic malignancies led to a new worldwide consensus to introduce image guidance to gynecologic radiation therapy, particularly to brachytherapy. The book summarizes the changed practice of management: treatment planning for cervical cancer, not modified for over 60 years, has been shifted to an image-based approach, endometrial cancer management with an increase in the use of chemotherapy and vaginal brachytherapy, and vaginal cancer therapy including image guidance and high-dose delivery with IMRT. (orig.)

  11. Image guidance in trans-sphenoidal surgery for giant pituitary adenomas: Luxury or necessity?

    Directory of Open Access Journals (Sweden)

    Deepak Agrawal

    2012-01-01

    Full Text Available Background: In spite of availability of image guidance (neuronavigation at major centers around the world, most trans-sphenoidal surgeries for pituitary adenomas continue to be done under fluoroscopic control. On the other hand, the high mortality and morbidity for giant pituitary adenomas is mainly due to inadequate tumor removal. Aims and Objectives: The objective of this study was to study to utility of image guidance in trans-sphenoidal surgeries for optimizing tumor removal in giant pituitary adenomas. Materials and Methods: This was a prospective study carried out over a two years (January 2009-December 2010 in the Department of Neurosurgery, All India Institute of Medical Sciences. Patients with giant pituitary adenomas who underwent trans-sphenoidal surgery by the author were included. All surgeries were done under image-guidance only and no fluoroscopy was employed. Trajectory was defined using the image guidance and bone work done accordingly to optimize tumor removal. All patients had a contrast CT of the head done within 48 h of surgery to see for residual tumor. Observations and Results: Sixteen patients with pituitary adenomas were operated using only image-guidance in the study period. Twelve patients had virgin tumors and four patients had recurrent/residual tumors. In four patients, noncontrast MR images were used in for image guidance and contrast CT images were used in the rest. The mean set up time for image-guidance was 11 min (range 7-15 min. The mean ′′overall accuracy of registration′′ was 1.6 mm (range 1.4-2.1 mm. The mean operating time was 72 min (range 52-96 min. In all cases, midline and the relation of the carotid artery to the sella could be confirmed using the image-guidance. There were no intraoperative complications. Postoperative scans showed residual tumor in nine patients. The residual tumor was 25% in one patient (with a fibrous recurrent/residual tumor. Conclusions: Image guidance markedly improves

  12. Expediting model-based optoacoustic reconstructions with tomographic symmetries

    International Nuclear Information System (INIS)

    Lutzweiler, Christian; Deán-Ben, Xosé Luís; Razansky, Daniel

    2014-01-01

    Purpose: Image quantification in optoacoustic tomography implies the use of accurate forward models of excitation, propagation, and detection of optoacoustic signals while inversions with high spatial resolution usually involve very large matrices, leading to unreasonably long computation times. The development of fast and memory efficient model-based approaches represents then an important challenge to advance on the quantitative and dynamic imaging capabilities of tomographic optoacoustic imaging. Methods: Herein, a method for simplification and acceleration of model-based inversions, relying on inherent symmetries present in common tomographic acquisition geometries, has been introduced. The method is showcased for the case of cylindrical symmetries by using polar image discretization of the time-domain optoacoustic forward model combined with efficient storage and inversion strategies. Results: The suggested methodology is shown to render fast and accurate model-based inversions in both numerical simulations andpost mortem small animal experiments. In case of a full-view detection scheme, the memory requirements are reduced by one order of magnitude while high-resolution reconstructions are achieved at video rate. Conclusions: By considering the rotational symmetry present in many tomographic optoacoustic imaging systems, the proposed methodology allows exploiting the advantages of model-based algorithms with feasible computational requirements and fast reconstruction times, so that its convenience and general applicability in optoacoustic imaging systems with tomographic symmetries is anticipated

  13. A maximum entropy reconstruction technique for tomographic particle image velocimetry

    International Nuclear Information System (INIS)

    Bilsky, A V; Lozhkin, V A; Markovich, D M; Tokarev, M P

    2013-01-01

    This paper studies a novel approach for reducing tomographic PIV computational complexity. The proposed approach is an algebraic reconstruction technique, termed MENT (maximum entropy). This technique computes the three-dimensional light intensity distribution several times faster than SMART, using at least ten times less memory. Additionally, the reconstruction quality remains nearly the same as with SMART. This paper presents the theoretical computation performance comparison for MENT, SMART and MART, followed by validation using synthetic particle images. Both the theoretical assessment and validation of synthetic images demonstrate significant computational time reduction. The data processing accuracy of MENT was compared to that of SMART in a slot jet experiment. A comparison of the average velocity profiles shows a high level of agreement between the results obtained with MENT and those obtained with SMART. (paper)

  14. Construction of Korean male tomographic model segmented from PET-CT data

    International Nuclear Information System (INIS)

    Lee, Choon Sik; Park, Sang Kyun; Lee, Jai Ki

    2004-01-01

    Tomographic human models provide currently the most realistic representation of human anatomy for radiation dosimetry calculation. Most of the models have been constructed by using computed tomographic (CT) or magnetic resonance (MR) images obtained from a single individual. Each scan has its inherent advantages and disadvantages. CT scan gives a considerable radiation dose to a subject, and MR scan takes too long time to get clear images of an immobile subject. An emerging source of medical images for the construction of tomographic models is PET-CT, which is performed when looking for cancer. In this study, a tomographic model of Korean adult male was developed by processing whole-body CT images of a PET-CT-scanned healthy volunteer. The 343 slices of the CT images were semi-automatically segmented layer by layer using a graphic software and screen digitizer. The 3rd Korean tomographic model, named KRMAN-2, consisting of 300x150x344 voxels of a size of 2x2x5mm 3 , was constructed. Examples of application to Monte Carlo radiation dosimetry calculation in idealized whole-body irradiations were given and discussed

  15. Space imaging infrared optical guidance for autonomous ground vehicle

    Science.gov (United States)

    Akiyama, Akira; Kobayashi, Nobuaki; Mutoh, Eiichiro; Kumagai, Hideo; Yamada, Hirofumi; Ishii, Hiromitsu

    2008-08-01

    We have developed the Space Imaging Infrared Optical Guidance for Autonomous Ground Vehicle based on the uncooled infrared camera and focusing technique to detect the objects to be evaded and to set the drive path. For this purpose we made servomotor drive system to control the focus function of the infrared camera lens. To determine the best focus position we use the auto focus image processing of Daubechies wavelet transform technique with 4 terms. From the determined best focus position we transformed it to the distance of the object. We made the aluminum frame ground vehicle to mount the auto focus infrared unit. Its size is 900mm long and 800mm wide. This vehicle mounted Ackerman front steering system and the rear motor drive system. To confirm the guidance ability of the Space Imaging Infrared Optical Guidance for Autonomous Ground Vehicle we had the experiments for the detection ability of the infrared auto focus unit to the actual car on the road and the roadside wall. As a result the auto focus image processing based on the Daubechies wavelet transform technique detects the best focus image clearly and give the depth of the object from the infrared camera unit.

  16. TU-A-201-00: Image Guidance Technologies and Management Strategies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    Recent years have seen a widespread proliferation of available in-room image guidance systems for radiation therapy target localization with many centers having multiple in-room options. In this session, available imaging systems for in-room IGRT will be reviewed highlighting the main differences in workflow efficiency, targeting accuracy and image quality as it relates to target visualization. Decision-making strategies for integrating these tools into clinical image guidance protocols that are tailored to specific disease sites like H&N, lung, pelvis, and spine SBRT will be discussed. Learning Objectives: Major system characteristics of a wide range of available in-room imaging systems for IGRT. Advantages / disadvantages of different systems for site-specific IGRT considerations. Concepts of targeting accuracy and time efficiency in designing clinical imaging protocols.

  17. WE-E-18A-11: Fluoro-Tomographic Images From Projections of On-Board Imager (OBI) While Gantry Is Moving

    Energy Technology Data Exchange (ETDEWEB)

    Yi, B; Hu, E; Yu, C; Lasio, G [Univ. of Maryland School Of Medicine, Baltimore, MD (United States)

    2014-06-15

    Purpose: A method to generate a series of fluoro-tomographic images (FTI) of the slice of interest (SOI) from the projection images of the On-board imager (OBI) while gantry is moving is developed and tested. Methods: Tomographic image via background subtraction, TIBS has been published by our group. TIBS uses a priori anatomical information from a previous CT scan to isolate a SOI from a planar kV image by factoring out the attenuations by tissues outside the SOI (background). We extended the idea to 4D TIBS, which enables to generate from the projection of different gantry angles. A set of background images for different angles are prepared. A background image at a given gantry angle is subtracted from the projection image at the same angle to generate a TIBS image. Then the TIBS image is converted to a reference angle. The 4D TIBS is the set of TIBS that originated from gantry angles other than the reference angle. Projection images of lung patients for CBCT acquisition are used to test the 4D TIBS. Results: Fluoroscopic images of a coronal plane of lung patients are acquired from the CBCT projections at different gantry angles and times. Change of morphology of hilar vessels due to breathing and heart beating are visible in the coronal plane, which are generated from the set of the projection images at gantry angles other than antero-posterior. Breathing surrogate or sorting process is not needed. Unlike tomosynthesis, FTI from 4D TIBS maintains the independence of each of the projections thereby reveals temporal variations within the SOI. Conclusion: FTI, fluoroscopic imaging of a SOI with x-ray projections, directly generated from the x-ray projection images at different gantry angles is tested with a lung case and proven feasible. This technique can be used for on-line imaging of moving targets. NIH Grant R01CA133539.

  18. Cardiac imaging systems and methods employing computerized tomographic scanning

    International Nuclear Information System (INIS)

    Richey, J.B.; Wake, R.H.; Walters, R.G.; Hunt, W.F.; Cool, S.L.

    1980-01-01

    The invention relates to cardiac imaging systems and methods employing computerised tomographic scanning. Apparatus is described which allows an image of the radiation attenuation of the heart at a desired phase of the cardiac cycle. The patients ECG signal can be used in a transverse-and-rotate type CT scanner as a time base, so that the beam reaches the heart at a desired phase of the cardiac cycle, or, in a purely rotational-type CT scanner continuously generated scan data is only stored for corresponding phases of successive cardiac cycles. Alternatively, gating of the beams themselves by shuttering or switching the power supply can be controlled by the ECG signal. A pacemaker is used to stabilize the cardiac period. Also used is a system for recognising unacceptable variations in the cardiac period and discarding corresponding scan data. In a transverse-and-rotate type fan-beam CT scanner, the effective beam width is narrowed to reduce the duration of the traverse of the heart. (U.K.)

  19. Scanning tomographic particle image velocimetry applied to a turbulent jet

    KAUST Repository

    Casey, T. A.

    2013-02-21

    We introduce a modified tomographic PIV technique using four high-speed video cameras and a scanning pulsed laser-volume. By rapidly illuminating adjacent subvolumes onto separate video frames, we can resolve a larger total volume of velocity vectors, while retaining good spatial resolution. We demonstrate this technique by performing time-resolved measurements of the turbulent structure of a round jet, using up to 9 adjacent volume slices. In essence this technique resolves more velocity planes in the depth direction by maintaining optimal particle image density and limiting the number of ghost particles. The total measurement volumes contain between 1 ×106 and 3 ×106 velocity vectors calculated from up to 1500 reconstructed depthwise image planes, showing time-resolved evolution of the large-scale vortical structures for a turbulent jet of Re up to 10 000.

  20. Implementation of 3D tomographic visualisation through planar ICT data from experimental gamma-ray tomographic system

    International Nuclear Information System (INIS)

    Umesh Kumar; Singh, Gursharan; Ravindran, V.R.

    2001-01-01

    Industrial Computed Tomography (ICT) is one of the latest methods of non-destructive testing and examination. Different prototypes of Computed Industrial Tomographic Imaging System (CITIS) have been developed and experimental data have been generated in Isotope Applications Division. The experimental gamma-rays based tomographic imaging system comprises of beam generator containing approx. 220 GBq (6 Curies) of 137 Cs, a single NaI(Tl) -PMT integral assembly in a thick shielding and associated electronics, stepper motor controlled mechanical manipulator, collimators and required software. CITIS data is normally acquired in one orientation of the sample. It may be sometimes required to view a tomographic plane in a different orientation. Also, 3D visualization may be required with the available 2D data set. All these can be achieved by processing the available data. We have customized some of the routines for this purpose provided IDL (Integrated Data Language) package to suit our requirements. The present paper discusses methodology adopted for this purpose with an illustrative example. (author)

  1. Linear information retrieval method in X-ray grating-based phase contrast imaging and its interchangeability with tomographic reconstruction

    Science.gov (United States)

    Wu, Z.; Gao, K.; Wang, Z. L.; Shao, Q. G.; Hu, R. F.; Wei, C. X.; Zan, G. B.; Wali, F.; Luo, R. H.; Zhu, P. P.; Tian, Y. C.

    2017-06-01

    In X-ray grating-based phase contrast imaging, information retrieval is necessary for quantitative research, especially for phase tomography. However, numerous and repetitive processes have to be performed for tomographic reconstruction. In this paper, we report a novel information retrieval method, which enables retrieving phase and absorption information by means of a linear combination of two mutually conjugate images. Thanks to the distributive law of the multiplication as well as the commutative law and associative law of the addition, the information retrieval can be performed after tomographic reconstruction, thus simplifying the information retrieval procedure dramatically. The theoretical model of this method is established in both parallel beam geometry for Talbot interferometer and fan beam geometry for Talbot-Lau interferometer. Numerical experiments are also performed to confirm the feasibility and validity of the proposed method. In addition, we discuss its possibility in cone beam geometry and its advantages compared with other methods. Moreover, this method can also be employed in other differential phase contrast imaging methods, such as diffraction enhanced imaging, non-interferometric imaging, and edge illumination.

  2. The use of image-guidance during transsphenoidal pituitary surgery in the United States

    Science.gov (United States)

    Chung, Thomas K.; Riley, Kristen O.

    2015-01-01

    Background: Intraoperative image guidance is a useful modality for transsphenoidal pituitary surgery. However, the outcomes associated with this technology have not been systematically evaluated. Objective: The purpose of the study was to quantify complication rates with and without the use of image guidance during transsphenoidal pituitary surgery using a nationwide database with broadly applicable results. Methods: A retrospective analysis of the Nationwide Inpatient Sample was performed from 2007 to 2011. Transsphenoidal pituitary resections for adenomas were identified by International Classification of Diseases-9th Revision, Clinical Modification code. The effect of image guidance on cerebrospinal fluid (CSF) leak complications and cost-benefit was analyzed. Results: A total of 48,848 transsphenoidal pituitary resections were identified, of which 77.5% were partial resections and 22.5% were complete. Pathologic indications included benign (89.3%), malignant primary (0.6%), and malignant secondary (0.4%). Complications included same-stay death (0.4%), CSF leak (8.8%), postoperative CSF rhinorrhea (1.9%), diabetes insipidus (12.4%), and meningitis (0.4%). Image guidance was employed in 7% (n = 3401) of all cases. When analyzed by modality, computed tomography (CT)-assisted procedures had lower CSF rhinorrhea rates (1.1%) compared with cases with no image guidance (1.9%), whereas magnetic resonance (MR)-assisted procedures had the highest rates (2.7%, χ2 p surgery had significantly shorter length of stay (2.9 days) versus no image guidance (3.7 days, p surgery is associated with a lower rate of CSF leak, shorter length of stay, and lower cost compared with patients without image guidance. Further studies that control for severity and extent of disease are warranted to confirm this finding. PMID:25975254

  3. Investigation of the noise effect on tomographic reconstructions for a tangentially viewing vacuum ultraviolet imaging diagnostic

    International Nuclear Information System (INIS)

    Ming, Tingfeng; Ohdachi, Satoshi; Suzuki, Yasuhiro

    2011-01-01

    Tomographic reconstruction for a tangentially viewing two-dimensional (2D) imaging system is studied. A method to calculate the geometry matrix in 2D tomography is introduced. An algorithm based on a Phillips-Tikhonov (P-T) type regularization method is investigated, and numerical tests using the P-T method are conducted with both tokamak and Heliotron configurations. The numerical tests show that the P-T method is not sensitive to the added noise levels and the emission profiles with higher mode numbers can be reconstructed with adequate resolution. The results indicate that this method is suitable for 2D tomographic reconstruction for a tangentially viewing vacuum ultraviolet telescope system. (author)

  4. Combination tomographic and cardiographic ultrasonic imaging method and system

    International Nuclear Information System (INIS)

    Yano, T.; Fukukita, H.; Fukumoto, A.; Hayakawa, Y.; Irioka, K.

    1984-01-01

    Ultrasonic echo signals are successively sampled and converted to digital echo data which are written into a first digital memory column by column and then read out row by row into a first buffer memory. The digital echo data which are derived in response to beams successively transmitted in a predetermined direction are written into columns of a second digital memory and read out of the memory in rows into a second buffer memory. The data stored in the first and second buffer memories are read out for digital-to-analog conversion and selectively applied within a television ''frame'' interval to control electron beam intensity of a single cathode ray tube so as to present tomographic and cardiographic images in different display areas of the tube

  5. A tomograph VMEbus parallel processing data acquisition system

    International Nuclear Information System (INIS)

    Wilkinson, N.A.; Rogers, J.G.; Atkins, M.S.

    1989-01-01

    This paper describes a VME based data acquisition system suitable for the development of Positron Volume Imaging tomographs which use 3-D data for improved image resolution over slice-oriented tomographs. the data acquisition must be flexible enough to accommodate several 3-D reconstruction algorithms; hence, a software-based system is most suitable. Furthermore, because of the increased dimensions and resolution of volume imaging tomographs, the raw data event rate is greater than that of slice-oriented machines. These dual requirements are met by our data acquisition system. Flexibility is achieved through an array of processors connected over a VMEbus, operating asynchronously and in parallel. High raw data throughput is achieved using a dedicated high speed data transfer device available for the VMEbus. The device can attain a raw data rate of 2.5 million coincidence events per second for raw events which are 64 bits wide

  6. Evaluation of a mobile augmented reality application for image guidance of neurosurgical interventions.

    Science.gov (United States)

    Kramers, Matthew; Armstrong, Ryan; Bakhshmand, Saeed M; Fenster, Aaron; de Ribaupierre, Sandrine; Eagleson, Roy

    2014-01-01

    Image guidance can provide surgeons with valuable contextual information during a medical intervention. Often, image guidance systems require considerable infrastructure, setup-time, and operator experience to be utilized. Certain procedures performed at bedside are susceptible to navigational errors that can lead to complications. We present an application for mobile devices that can provide image guidance using augmented reality to assist in performing neurosurgical tasks. A methodology is outlined that evaluates this mode of visualization from the standpoint of perceptual localization, depth estimation, and pointing performance, in scenarios derived from a neurosurgical targeting task. By measuring user variability and speed we can report objective metrics of performance for our augmented reality guidance system.

  7. SU-E-J-06: Additional Imaging Guidance Dose to Patient Organs Resulting From X-Ray Tubes Used in CyberKnife Image Guidance System

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, A; Ding, G [Vanderbilt University, Nashville, TN (United States)

    2015-06-15

    Purpose: The use of image-guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system. Methods: Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x-ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kV and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field-of-view of each site were calculated for a single image acquisition from both of the orthogonal x-ray tubes. Results: Average organ doses were <1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site. Conclusion: The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (>100) could reach 10–20 cGy for a typical treatment fraction.

  8. Automating the segmentation of medical images for the production of voxel tomographic computational models

    International Nuclear Information System (INIS)

    Caon, M.

    2001-01-01

    Radiation dosimetry for the diagnostic medical imaging procedures performed on humans requires anatomically accurate, computational models. These may be constructed from medical images as voxel-based tomographic models. However, they are time consuming to produce and as a consequence, there are few available. This paper discusses the emergence of semi-automatic segmentation techniques and describes an application (iRAD) written in Microsoft Visual Basic that allows the bitmap of a medical image to be segmented interactively and semi-automatically while displayed in Microsoft Excel. iRAD will decrease the time required to construct voxel models. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

  9. From tomographic images to fault heterogeneities

    Directory of Open Access Journals (Sweden)

    A. Amato

    1994-06-01

    Full Text Available Local Earthquake Tomography (LET is a useful tool for imaging lateral heterogeneities in the upper crust. The pattern of P- and S-wave velocity anomalies, in relation to the seismicity distribution along active fault zones. can shed light on the existence of discrete seismogenic patches. Recent tomographic studies in well monitored seismic areas have shown that the regions with large seismic moment release generally correspond to high velocity zones (HVZ's. In this paper, we discuss the relationship between the seismogenic behavior of faults and the velocity structure of fault zones as inferred from seismic tomography. First, we review some recent tomographic studies in active strike-slip faults. We show examples from different segments of the San Andreas fault system (Parkfield, Loma Prieta, where detailed studies have been carried out in recent years. We also show two applications of LET to thrust faults (Coalinga, Friuli. Then, we focus on the Irpinia normal fault zone (South-Central Italy, where a Ms = 6.9 earthquake occurred in 1980 and many thousands of attershock travel time data are available. We find that earthquake hypocenters concentrate in HVZ's, whereas low velocity zones (LVZ’ s appear to be relatively aseismic. The main HVZ's along which the mainshock rupture bas propagated may correspond to velocity weakening fault regions, whereas the LVZ's are probably related to weak materials undergoing stable slip (velocity strengthening. A correlation exists between this HVZ and the area with larger coseismic slip along the fault, according to both surface evidence (a fault scarp as high as 1 m and strong ground motion waveform modeling. Smaller wave-length, low-velocity anomalies detected along the fault may be the expression of velocity strengthening sections, where aseismic slip occurs. According to our results, the rupture at the nucleation depth (~ 10-12 km is continuous for the whole fault lenoth (~ 30 km, whereas at shallow depth

  10. Industrial dynamic tomographic reconstruction

    International Nuclear Information System (INIS)

    Oliveira, Eric Ferreira de

    2016-01-01

    The state of the art methods applied to industrial processes is currently based on the principles of classical tomographic reconstructions developed for tomographic patterns of static distributions, or is limited to cases of low variability of the density distribution function of the tomographed object. Noise and motion artifacts are the main problems caused by a mismatch in the data from views acquired in different instants. All of these add to the known fact that using a limited amount of data can result in the presence of noise, artifacts and some inconsistencies with the distribution under study. One of the objectives of the present work is to discuss the difficulties that arise from implementing reconstruction algorithms in dynamic tomography that were originally developed for static distributions. Another objective is to propose solutions that aim at reducing a temporal type of information loss caused by employing regular acquisition systems to dynamic processes. With respect to dynamic image reconstruction it was conducted a comparison between different static reconstruction methods, like MART and FBP, when used for dynamic scenarios. This comparison was based on a MCNPx simulation as well as an analytical setup of an aluminum cylinder that moves along the section of a riser during the process of acquisition, and also based on cross section images from CFD techniques. As for the adaptation of current tomographic acquisition systems for dynamic processes, this work established a sequence of tomographic views in a just-in-time fashion for visualization purposes, a form of visually disposing density information as soon as it becomes amenable to image reconstruction. A third contribution was to take advantage of the triple color channel necessary to display colored images in most displays, so that, by appropriately scaling the acquired values of each view in the linear system of the reconstruction, it was possible to imprint a temporal trace into the regularly

  11. Positron Tomographic Imaging Of The Liver With Ga-68 Iron Hydroxide Colloid

    Science.gov (United States)

    Kumar, Bharath; Miller, Tom R.; Siegel, Barry A.; Mathias, Carla J.; Markham, Joanne; Ehrhardt, Gary J.; Welch, Michael J.

    1980-08-01

    A new radiopharmaceutical, 68Ga-iron hydroxide colloid, for hepatic imaging by positron emission tomography (PET) was prepared from the eluate of a "Ge-68Ga solvent extraction generator. In rats, 84% of the administered dose of colloid localized in the liver and 4.6% accumulated in the spleen. Initial imaging studies in normal dogs showed close correspondence of the findings by PET and transmission computed tomography (CT). PET with 68Ga-colloid was performed in 10 patients with hepatic metastases demonstrated by conventional scintigraphy with 99mTc-sulfur colloid. All focal defects noted on the conventional scintigrams were easily identified and generally seen more clearly by PET. In one patient, lesions not identified on the initial 99mTc-sulfur colloid images were demonstrated by PET. The positron tomographic images were compared with those obtained by CT in 7 patients; the two studies showed comparable findings in 5 patients, whereas PET more clearly showed multiple lesions in 2. Our results suggest that PET is a suitable technique for obtaining high-contrast, cross-sectional images of large abdominal organs. Emission computed tomography with positron-emitting radionuclides shows promise as an important new tool for clinical research (1-4). Unfortunately, wide clinical application of positron-emission tomography (PET) is presently limited by the need for an expensive, hospital-based cyclotron facility and highly trained professional and technical personnel to synthesize the radiopharmaceuticals labeled with the very short-lived radionuclides 11c, 13N, 150 and 18 F that are employed most commonly in such studies. These difficulties may be circumvented in part by the use of a simple generator system that produces the positron-emitting radionuclide 68Ga (T1/2 = 68 min) from the long-lived parent 68Ge (T1/2 = 275 days) (5-7). A large number of radiopharmaceuticals of potential clinical interest may be prepared readily from the eluate of such a generator (6

  12. Visual tracking for multi-modality computer-assisted image guidance

    Science.gov (United States)

    Basafa, Ehsan; Foroughi, Pezhman; Hossbach, Martin; Bhanushali, Jasmine; Stolka, Philipp

    2017-03-01

    With optical cameras, many interventional navigation tasks previously relying on EM, optical, or mechanical guidance can be performed robustly, quickly, and conveniently. We developed a family of novel guidance systems based on wide-spectrum cameras and vision algorithms for real-time tracking of interventional instruments and multi-modality markers. These navigation systems support the localization of anatomical targets, support placement of imaging probe and instruments, and provide fusion imaging. The unique architecture - low-cost, miniature, in-hand stereo vision cameras fitted directly to imaging probes - allows for an intuitive workflow that fits a wide variety of specialties such as anesthesiology, interventional radiology, interventional oncology, emergency medicine, urology, and others, many of which see increasing pressure to utilize medical imaging and especially ultrasound, but have yet to develop the requisite skills for reliable success. We developed a modular system, consisting of hardware (the Optical Head containing the mini cameras) and software (components for visual instrument tracking with or without specialized visual features, fully automated marker segmentation from a variety of 3D imaging modalities, visual observation of meshes of widely separated markers, instant automatic registration, and target tracking and guidance on real-time multi-modality fusion views). From these components, we implemented a family of distinct clinical and pre-clinical systems (for combinations of ultrasound, CT, CBCT, and MRI), most of which have international regulatory clearance for clinical use. We present technical and clinical results on phantoms, ex- and in-vivo animals, and patients.

  13. Method of making tomographic images of X-rayed objects

    International Nuclear Information System (INIS)

    Eickel, R.

    1979-01-01

    A tomographic image of a selected layer of a stationary object is made by moving the source of X-rays along a first path at one side of the selected layer and by moving an ionography imaging chamber which contains a dielectric receptor sheet along a second path at the other side of the selected layer. The movement of the sheet is synchronized with movement of the source of X-rays and includes a translatory movement in a direction counter to the direction of movement of the source, a pivotal movement to maintain the sheet in a plane which is normal to the central beam of the bundle of X-rays, and a sidewise movement to vary the distance between the selected layer and the sheet so that the length of the projection of selected layer upon the sheet remains unchanged. If the sheet is rectangular, the pivotal movement is performed about an axis which is located in the plane of the selected layer and is parallel to the shorter sides of the sheet

  14. A hybrid optical system for broadband imaging in guidance and control

    Science.gov (United States)

    Wu, Xiaofang; Jiang, Yuesong; Shen, Chunyan; Zhao, Yiming

    2006-11-01

    A binary optics method has been adopted to improve upon a conventional optical system in guidance and control, and a hybrid broadband imaging system that includes a binary surface is analyzed and evaluated by optical design software ZEMAX. The practical design shows that the introduction of binary optics can simplify the structure of the imaging system and reduce the size and weight of the broadband guidance and control system. Moreover, it can help to acquire images of radiation of different wavelengths from targets; hence it will result in improved overall performance of missiles in wars.

  15. A system dedicated to the viewing and handling of tomographic images obtained by magnetic resonance

    International Nuclear Information System (INIS)

    Slaets, Joan F.W.; Almeida, Lirio O.B.; Traina, Agma J.M.

    1992-01-01

    The present work describes the development of a dedicated system to be used in visualization and manipulation of a MR images. The graphics environment as well as the tool kit were developed for the dedicated TMS34010 based hardware. The developed software offers a compact kernel with primitives to support the creation and manipulation windows and menus directly in 'C' language. This work is fundamental for the implementation of a user friendly interface build to operate and visualize tomographic images. This tools are essential for the selection an archiving of images planes as used in clinical applications. (author)

  16. Three-dimensional Image Fusion Guidance for Transjugular Intrahepatic Portosystemic Shunt Placement.

    Science.gov (United States)

    Tacher, Vania; Petit, Arthur; Derbel, Haytham; Novelli, Luigi; Vitellius, Manuel; Ridouani, Fourat; Luciani, Alain; Rahmouni, Alain; Duvoux, Christophe; Salloum, Chady; Chiaradia, Mélanie; Kobeiter, Hicham

    2017-11-01

    To assess the safety, feasibility and effectiveness of image fusion guidance with pre-procedural portal phase computed tomography with intraprocedural fluoroscopy for transjugular intrahepatic portosystemic shunt (TIPS) placement. All consecutive cirrhotic patients presenting at our interventional unit for TIPS creation from January 2015 to January 2016 were prospectively enrolled. Procedures were performed under general anesthesia in an interventional suite equipped with flat panel detector, cone-beam computed tomography (CBCT) and image fusion technique. All TIPSs were placed under image fusion guidance. After hepatic vein catheterization, an unenhanced CBCT acquisition was performed and co-registered with the pre-procedural portal phase CT images. A virtual path between hepatic vein and portal branch was made using the virtual needle path trajectory software. Subsequently, the 3D virtual path was overlaid on 2D fluoroscopy for guidance during portal branch cannulation. Safety, feasibility, effectiveness and per-procedural data were evaluated. Sixteen patients (12 males; median age 56 years) were included. Procedures were technically feasible in 15 of the 16 patients (94%). One procedure was aborted due to hepatic vein catheterization failure related to severe liver distortion. No periprocedural complications occurred within 48 h of the procedure. The median dose-area product was 91 Gy cm 2 , fluoroscopy time 15 min, procedure time 40 min and contrast media consumption 65 mL. Clinical benefit of the TIPS placement was observed in nine patients (56%). This study suggests that 3D image fusion guidance for TIPS is feasible, safe and effective. By identifying virtual needle path, CBCT enables real-time multiplanar guidance and may facilitate TIPS placement.

  17. Method and apparatus for producing tomographic images

    International Nuclear Information System (INIS)

    Annis, M.

    1989-01-01

    A device useful in producing a tomographic image of a selected slice of an object to be examined is described comprising: a source of penetrating radiation, sweep means for forming energy from the source into a pencil beam and repeatedly sweeping the pencil beam over a line in space to define a sweep plane, first means for supporting an object to be examined so that the pencil beam intersections the object along a path passing through the object and the selected slice, line collimating means for filtering radiation scattered by the object, the line collimating means having a field of view which intersects and sweep plane in a bounded line so that the line collimating means passes only radiation scattered by elementary volumes of the object lying along the bounded line, and line collimating means including a plurality of channels such substantially planar in form to collectively define the field of view, the channels oriented so that pencil beam sweeps along the bounded line as a function of time, and radiation detector means responsive to radiation passed by the line collimating means

  18. Positron tomographic imaging of the liver: 68Ga iron hydroxide colloid

    International Nuclear Information System (INIS)

    Kumar, B.; Miller, T.R.; Siegel, B.A.; Mathias, C.J.; Markham, J.; Ehrhardt, G.J.; Welch, M.J.

    1981-01-01

    A new radiopharmaceutical, 68 Ga iron hydroxide colloid, for hepatic imaging by positron emission tomography was prepared from the eluate of a 68 Ge- 68 Ga solvent extraction generator. In rats, 84% of the administered dose of colloid localized in the liver and 4.6% accumulated in the spleen. Initial imaging studies in normal dogs showed close correspondence of the findings by positron tomography and transmission computed tomography. Emission tomography with 68 Ga-colloid was performed in 10 patients with hepatic metastases demonstrated by conventional /sup 99m/Tc-sulfur colloid scintigraphy. All focal defects noted on the conventional scintigrams were easily identified and generally were seen more clearly by positron tomography. In one patient, additional lesions not identified on the initial /sup 99m/Tc-sulfur colloid images were demonstrated. The positron tomographic images were compared with those obtained by transmission computed tomography in seven patients; the two studies showed comparable findings in five patients, whereas positron tomography more clearly showed multiple lesions in two. Our results suggest that positron emission tomography is a suitable technique for obtaining high contrast, cross-sectional images of large abdominal organs

  19. Positron tomographic imaging of the liver: 68Ga iron hydroxide colloid

    International Nuclear Information System (INIS)

    Kumar, B.; Miller, T.R.; Siegel, B.A.; Mathias, C.J.; Markham, J.; Ehrhardt, G.J.; Welch, M.J.

    1981-01-01

    A new radiopharmaceutical, 68 Ga ion hydroxide colloid, for hepatic imaging by positron emission tomography was prepared from the eluate of a 68 Ge- 68 Ga solvent extraction generator. In rats, 84% of the administered dose of colloid localized in the liver and 4.6% accumulated in the spleen. Initial imaging studies in normal dogs showed close correspondence of the findings by positron tomography and transmission computed tomography. Emission tomography with 68 Ga-colloid was performed in 10 patients with hepatic metastases demonstrated by conventional 99mTc sulfur colloid scintigraphy. All focal defects noted on the conventional scintigrams were easily identified and generally were seen more clearly by positron tomography. In one patient, additional lesions not identified on the initial 99mTc sulfur colloid images were demonstrated. The positron tomographic images were compared with those obtained by transmission computed tomography in seven patients; the two studies showed comparable findings in five patients, whereas positron tomography more clearly showed multiple lesions in two. Our results suggest that positron emission tomography is a suitable technique for obtaining high contrast, cross-sectional images of large abdominal organs

  20. The development of a compact positron tomograph for prostate imaging

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Jennifer S.; Qi, Jinyi; Derenzo, Stephen E.; Moses, William W.; Huesman, Ronald H.; Budinger, Thomas F.

    2002-12-17

    We give design details and expected image results of a compact positron tomograph designed for prostate imaging that centers a patient between a pair of external curved detector banks (ellipse: 45 cm minor, 70 cm major axis). The bottom bank is fixed below the patient bed, and the top bank moves upward for patient access and downward for maximum sensitivity. Each bank is composed of two rows (axially) of 20 CTI PET Systems HR+ block detectors, forming two arcs that can be tilted to minimize attenuation. Compared to a conventional PET system, our camera uses about one-quarter the number of detectors and has almost two times higher solid angle coverage for a central point source, because the detectors are close to the patient. The detectors are read out by modified CTI HRRT data acquisition electronics. The individual detectors are angled in the plane to point towards the prostate to minimize reso

  1. Tomographic and analog 3-D simulations using NORA. [Non-Overlapping Redundant Image Array formed by multiple pinholes

    Science.gov (United States)

    Yin, L. I.; Trombka, J. I.; Bielefeld, M. J.; Seltzer, S. M.

    1984-01-01

    The results of two computer simulations demonstrate the feasibility of using the nonoverlapping redundant array (NORA) to form three-dimensional images of objects with X-rays. Pinholes admit the X-rays to nonoverlapping points on a detector. The object is reconstructed in the analog mode by optical correlation and in the digital mode by tomographic computations. Trials were run with a stick-figure pyramid and extended objects with out-of-focus backgrounds. Substitution of spherical optical lenses for the pinholes increased the light transmission sufficiently that objects could be easily viewed in a dark room. Out-of-focus aberrations in tomographic reconstruction could be eliminated using Chang's (1976) algorithm.

  2. Development of a portable computed tomographic scanner for on-line imaging of industrial piping systems

    International Nuclear Information System (INIS)

    Jaafar Abdullah; Mohd Arif Hamzah; Mohd Soyapi Mohd Yusof; Mohd Fitri Abdul Rahman; Fadil IsmaiI; Rasif Mohd Zain

    2003-01-01

    Computed tomography (CT) technology is being increasingly developed for industrial application. This paper presents the development of a portable computed tomographic scanner for on?line imaging of industrial piping systems. The theoretical approach, the system hardware, the data acquisition system and the adopted algorithm for image reconstruction are discussed. The scanner has large potential to be used to determine the extent of corrosion under insulation (CUI), to detect blockages, to measure the thickness of deposit/materials built-up on the walls and to improve understanding of material flow in pipelines. (Author)

  3. Image Guidance and Assessment of Radiation Induced Gene Therapy

    National Research Council Canada - National Science Library

    Pelizzari, Charles

    2004-01-01

    Image guidance and assessment techniques are being developed for combined radiation/gene therapy, which utilizes a radiation-inducible gene promoter to cause expression of tumor necrosis factor alpha...

  4. Imaging of turbulent structures and tomographic reconstruction of TORPEX plasma emissivity

    International Nuclear Information System (INIS)

    Iraji, D.; Furno, I.; Fasoli, A.; Theiler, C.

    2010-01-01

    In the TORPEX [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], a simple magnetized plasma device, low frequency electrostatic fluctuations associated with interchange waves, are routinely measured by means of extensive sets of Langmuir probes. To complement the electrostatic probe measurements of plasma turbulence and study of plasma structures smaller than the spatial resolution of probes array, a nonperturbative direct imaging system has been developed on TORPEX, including a fast framing Photron-APX-RS camera and an image intensifier unit. From the line-integrated camera images, we compute the poloidal emissivity profile of the plasma by applying a tomographic reconstruction technique using a pixel method and solving an overdetermined set of equations by singular value decomposition. This allows comparing statistical, spectral, and spatial properties of visible light radiation with electrostatic fluctuations. The shape and position of the time-averaged reconstructed plasma emissivity are observed to be similar to those of the ion saturation current profile. In the core plasma, excluding the electron cyclotron and upper hybrid resonant layers, the mean value of the plasma emissivity is observed to vary with (T e ) α (n e ) β , in which α=0.25-0.7 and β=0.8-1.4, in agreement with collisional radiative model. The tomographic reconstruction is applied to the fast camera movie acquired with 50 kframes/s rate and 2 μs of exposure time to obtain the temporal evolutions of the emissivity fluctuations. Conditional average sampling is also applied to visualize and measure sizes of structures associated with the interchange mode. The ω-time and the two-dimensional k-space Fourier analysis of the reconstructed emissivity fluctuations show the same interchange mode that is detected in the ω and k spectra of the ion saturation current fluctuations measured by probes. Small scale turbulent plasma structures can be detected and tracked in the reconstructed emissivity

  5. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    The configuration of a tomographic array in which the object can rotate about its axis is described. The X-ray detector is a cylindrical screen perpendicular to the axis of rotation. The X-ray source has a line-shaped focus coinciding with the axis of rotation. The beam is fan-shaped with one side of this fan lying along the axis of rotation. The detector screen is placed inside an X-ray image multiplier tube

  6. A tomograph VMEbus parallel processing data acquisition system

    International Nuclear Information System (INIS)

    Atkins, M.S.; Wilkinson, N.A.; Rogers, J.G.

    1988-11-01

    This paper describes a VME based data acquisition system suitable for the development of Positron Volume Imaging tomographs which use 3-D data for improved image resolution over slice-oriented tomographs. The data acquisition must be flexible enough to accommodate several 3-D reconstruction algorithms; hence, a software-based system is most suitable. Furthermore, because of the increased dimensions and resolution of volume imaging tomographs, the raw data event rate is greater than that of slice-oriented machines. These dual requirements are met by our data acquisition systems. Flexibility is achieved through an array of processors connected over a VMEbus, operating asynchronously and in parallel. High raw data throughput is achieved using a dedicated high speed data transfer device available for the VMEbus. The device can attain a raw data rate of 2.5 million coincidence events per second for raw events per second for raw events which are 64 bits wide. Real-time data acquisition and pre-processing requirements can be met by about forty 20 MHz Motorola 68020/68881 processors

  7. Localization and quantification of acute myocardial infarction by myocardial perfusion tomographic imaging

    International Nuclear Information System (INIS)

    Lin Xiufang; Min Changgeng; Lin Zhihu; Ke Ruoyi

    1994-01-01

    The authors reported the result of the quantification and localization of 30 clinically confirmed acute myocardial infarction patients in comparison with that of ECG. A left ventricle model was used to correct the area calculated by the method of Bull's eye. The result indicated that the infarction area calculated by the corrected Bull's eye method correlated closely with that determined by the ECG QRS scoring method (r = 0.706, P<0.01). Myocardial infarctions of all 30 patients were detected by both ECG and myocardial perfusion tomographic imaging. The accuracy of localization of myocardial infarction by myocardial perfusion imaging was similar to that of ECG in the anterior wall, anterior septum, anterior lateral and inferior wall, but superior to that of ECG in the apex, posterior lateral, posterior septum, and posterior wall

  8. Tomographic ventricular reconstruction using multiple view first-pass radionuclide angiography

    International Nuclear Information System (INIS)

    Lacy, J.L.; Ball, M.E.; Verani, M.S.; Wiles, H.; Roberts, R.

    1985-01-01

    In first-pass radionuclide angiography (FPRA) images of both left and right ventricles are uncontaminated by adjacent structures. Thus, the problem of tomographic reconstruction is vastly simplified compared to equilibrium blood pool imaging in which all structures are imaged simultaneously. Tomographic reconstruction from a limited number of views may thus be possible. A simple filtered interpolative back-projection reconstruction technique was employed. In this technique interpolation was used between sectional distributions at successive angles. Interpolations yielding 9 and 13 back projection angles of 22.5 0 and 15 0 were evaluated. Ventricular borders were obtained in each back-projected tomographic slice by location of the intensity level which provided correct total ventricular volume. Cast cross sections were quantitatively well represented by these borders. This ventricular border definition algorithm forms the basis for applications of the technique in animals and humans

  9. Enhanced Automated Guidance System for Horizontal Auger Boring Based on Image Processing.

    Science.gov (United States)

    Wu, Lingling; Wen, Guojun; Wang, Yudan; Huang, Lei; Zhou, Jiang

    2018-02-15

    Horizontal auger boring (HAB) is a widely used trenchless technology for the high-accuracy installation of gravity or pressure pipelines on line and grade. Differing from other pipeline installations, HAB requires a more precise and automated guidance system for use in a practical project. This paper proposes an economic and enhanced automated optical guidance system, based on optimization research of light-emitting diode (LED) light target and five automated image processing bore-path deviation algorithms. An LED light target was optimized for many qualities, including light color, filter plate color, luminous intensity, and LED layout. The image preprocessing algorithm, direction location algorithm, angle measurement algorithm, deflection detection algorithm, and auto-focus algorithm, compiled in MATLAB, are used to automate image processing for deflection computing and judging. After multiple indoor experiments, this guidance system is applied in a project of hot water pipeline installation, with accuracy controlled within 2 mm in 48-m distance, providing accurate line and grade controls and verifying the feasibility and reliability of the guidance system.

  10. A digital-signal-processor-based optical tomographic system for dynamic imaging of joint diseases

    Science.gov (United States)

    Lasker, Joseph M.

    Over the last decade, optical tomography (OT) has emerged as viable biomedical imaging modality. Various imaging systems have been developed that are employed in preclinical as well as clinical studies, mostly targeting breast imaging, brain imaging, and cancer related studies. Of particular interest are so-called dynamic imaging studies where one attempts to image changes in optical properties and/or physiological parameters as they occur during a system perturbation. To successfully perform dynamic imaging studies, great effort is put towards system development that offers increasingly enhanced signal-to-noise performance at ever shorter data acquisition times, thus capturing high fidelity tomographic data within narrower time periods. Towards this goal, I have developed in this thesis a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this instrument is a digital signal processor (DSP) that collects, collates, and processes the digitized data set. Complementary protocols between the DSP and a complex programmable logic device synchronizes the sampling process and organizes data flow. Instrument control is implemented through a comprehensive graphical user interface which integrates automated calibration, data acquisition, and signal post-processing. Real-time data is generated at frame rates as high as 140 Hz. An extensive dynamic range (˜190 dB) accommodates a wide scope of measurement geometries and tissue types. Performance analysis demonstrates very low system noise (˜1 pW rms noise equivalent power), excellent signal precision (˜0.04%--0.2%) and long term system stability (˜1% over 40 min). Experiments on tissue phantoms validate spatial and temporal accuracy of the system. As a potential new application of dynamic optical imaging I present the first application of this method to use vascular hemodynamics as a means of characterizing

  11. Volumetric image-guidance: Does routine usage prompt adaptive re-planning? An institutional review

    International Nuclear Information System (INIS)

    Tanyi, James A.; Fuss, Martin H.

    2008-01-01

    Purpose. To investigate how the use of volumetric image-guidance using an on-board cone-beam computed tomography (CBCT) system impacts on the frequency of adaptive re-planning. Material and methods. Treatment courses of 146 patients who have undergone a course of external beam radiation therapy (EBRT) using volumetric CBCT image-guidance were analyzed. Target locations included the brain, head and neck, chest, abdomen, as well as prostate and non-prostate pelvis. The majority of patients (57.5%) were treated with hypo-fractionated treatment regimens (three to 15 fraction courses). The frequency of image-guidance ranged from daily (87.7%) to weekly or twice weekly. The underlying medical necessity for adaptive re-planning as well as frequency and consequences of plan adaptation to dose-volume parameters was assessed. Results. Radiation plans of 34 patients (23.3%) were adapted at least once (up to six time) during their course of EBRT as a result of image-guidance CBCT review. Most common causes for adaptive planning were: tumor change (mostly shrinkage: 10 patients; four patients more than one re-plan), change in abdominal girth (systematic change in hollow organ filling; n=7, two patients more than one re-plan), weight loss (n=5), and systematic target setup deviation from simulation (n=5). Adaptive re-plan was required mostly for conventionally fractionated courses; only 5 patient plans undergoing hypo-fractionated treatment were adjusted. In over 91% of adapted plans, the dose-volume parameters did deviate from the prescribed plan parameters by more than 5% for at least 10% of the target volume, or organs-at-risk in close proximity to the target volume. Discussion. Routine use of volumetric image-guidance has in our practice increased the demand for adaptive re-planning. Volumetric CBCT image-guidance provides sufficient imaging information to reliably predict the need for dose adjustment. In the vast majority of cases evaluated, the initial and adapted dose

  12. Computerized tomographic in non-destructive testing

    International Nuclear Information System (INIS)

    Lopes, R.T.

    1988-01-01

    The process of computerized tomography has been developed for medical imaging purposes using tomographs with X-ray, and little attention has been given to others possibles applications of technique, because of its cost. As an alternative for the problem, we constructed a Tomographic System (STAC-1), using gamma-rays, for nonmedical applications. In this work we summarize the basic theory of reconstructing images using computerized tomography and we describe the considerations leading to the development of the experimental system. The method of reconstruction image implanted in the system is the filtered backprojection or convolution, with a digital filters system to carried on a pre-filtering in the projections. The experimental system is described, with details of control and the data processing. An alternative and a complementary system, using film as a detector is shown in preliminary form . This thesis discuss and shows the theorical and practical aspects, considered in the construction of the STAC-1, and also its limitations and apllications [pt

  13. Diagnostic value of myocardial tomographic imaging with 123I labelled BMIPP for exercise-induced angina pectoris

    International Nuclear Information System (INIS)

    Wang Lijuan; Kaname Akioka; Hiroyuki Yamagishi

    1999-01-01

    Objective: To evaluate the diagnostic value of resting myocardial tomographic imaging with 123 I labelled BMIPP ( 123 I-BMIPP SPECT) for exercise-induced angina pectoris by comparison with stress myocardial tomographic imaging with 201 Tl( 201 Tl SPECT). Methods: 123 I-BMIPP SPECT and 201 Tl SPECT were performed in 32 patients with exercise-induced angina pectoris and 12 normal controls. Left ventricle was divided into nine segments and uptake of 201 TL and 123 I-BMIPP was evaluated by four classes score method (defect score, DS). Results: In the patients with angina pectoris, segments of 201 Tl distribution abnormality were more than that of 123 I-BMIPP. Concordant rate between DS of the 20 '1Tl SPECT for detecting coronary artery stenosis were 62%, 92% and 70%, respectively, and 201 Tl SPECT were 84%, 83% and 84%, respectively. Sensitivity of 123 I-BMIPP SPECT was significantly lower than that of 201 Tl SPECT (P 123 I-BMIPP SPECT will be. Conclusions: The results indicated that to a certain extent, resting 123 I-BMIPP SPECT may has practical clinical value for detection of coronary artery stenosis, and determination of stenotic degree in the patients with exercise-induced angina pectoris

  14. First use of a truly-hybrid x-ray/MR imaging system for guidance of brain biopsy

    International Nuclear Information System (INIS)

    Fahrig, R.; Daniel, B.L.; Butts, K.; Pelc, N.J.; Heit, G.; Wen, Z.

    2003-01-01

    The use of a new hybrid imaging system for guidance of a brain biopsy is described. The system combines the strengths of MRI (soft-tissue contrast, arbitrary plane selection) with those of x-ray fluoroscopy (high-resolution real-time projection images, clear portrayal of bony structures) and allows switching between the imaging modalities without moving the patient. The biopsy was carried out using x-ray guidance for direction of the needle through the foramen ovale and MR guidance to target the soft-tissue lesion. Appropriate samples were acquired. The system could be particularly effective for guidance of those cases where motion, swelling, resection and other intra-operative anatomical changes cannot be accounted for using traditional stereotactic-based imaging approaches. (author)

  15. Statistical list-mode image reconstruction for the high resolution research tomograph

    International Nuclear Information System (INIS)

    Rahmim, A; Lenox, M; Reader, A J; Michel, C; Burbar, Z; Ruth, T J; Sossi, V

    2004-01-01

    We have investigated statistical list-mode reconstruction applicable to a depth-encoding high resolution research tomograph. An image non-negativity constraint has been employed in the reconstructions and is shown to effectively remove the overestimation bias introduced by the sinogram non-negativity constraint. We have furthermore implemented a convergent subsetized (CS) list-mode reconstruction algorithm, based on previous work (Hsiao et al 2002 Conf. Rec. SPIE Med. Imaging 4684 10-19; Hsiao et al 2002 Conf. Rec. IEEE Int. Symp. Biomed. Imaging 409-12) on convergent histogram OSEM reconstruction. We have demonstrated that the first step of the convergent algorithm is exactly equivalent (unlike the histogram-mode case) to the regular subsetized list-mode EM algorithm, while the second and final step takes the form of additive updates in image space. We have shown that in terms of contrast, noise as well as FWHM width behaviour, the CS algorithm is robust and does not result in limit cycles. A hybrid algorithm based on the ordinary and the convergent algorithms is also proposed, and is shown to combine the advantages of the two algorithms (i.e. it is able to reach a higher image quality in fewer iterations while maintaining the convergent behaviour), making the hybrid approach a good alternative to the ordinary subsetized list-mode EM algorithm

  16. Subduction and volcanism in the Iberia-North Africa collision zone from tomographic images of the upper mantle

    Science.gov (United States)

    Villaseñor, Antonio; Chevrot, Sébastien; Harnafi, Mimoun; Gallart, Josep; Pazos, Antonio; Serrano, Inmaculada; Córdoba, Diego; Pulgar, Javier A.; Ibarra, Pedro

    2015-11-01

    New tomographic images of the upper mantle beneath the westernmost Mediterranean suggest that the evolution of the region experienced two subduction-related episodes. First subduction of oceanic and/or extended continental lithosphere, now located mainly beneath the Betics at depths greater than 400 km, took place on a NW-SE oriented subduction zone. This was followed by a slab-tear process that initiated in the east and propagated to the west, leading to westward slab rollback and possibly lower crustal delamination. The current position of the slab tear is located approximately at 4°W, and to the west of this location the subducted lithosphere is still attached to the surface along the Gibraltar Arc. Our new P-wave velocity model is able to image the attached subducted lithosphere as a narrow high-velocity body extending to shallow depths, coinciding with the region of maximum curvature of the Gibraltar Arc, the occurrence of intermediate-depth earthquakes, and anomalously thick crust. This thick crust has a large influence in the measured teleseismic travel time residuals and therefore in the obtained P-wave tomographic model. We show that removing the effects of the thick crust significantly improves the shallow images of the slab and therefore the interpretations based on the seismic structure.

  17. Echocardiographic and Fluoroscopic Fusion Imaging for Procedural Guidance: An Overview and Early Clinical Experience.

    Science.gov (United States)

    Thaden, Jeremy J; Sanon, Saurabh; Geske, Jeffrey B; Eleid, Mackram F; Nijhof, Niels; Malouf, Joseph F; Rihal, Charanjit S; Bruce, Charles J

    2016-06-01

    There has been significant growth in the volume and complexity of percutaneous structural heart procedures in the past decade. Increasing procedural complexity and accompanying reliance on multimodality imaging have fueled the development of fusion imaging to facilitate procedural guidance. The first clinically available system capable of echocardiographic and fluoroscopic fusion for real-time guidance of structural heart procedures was approved by the US Food and Drug Administration in 2012. Echocardiographic-fluoroscopic fusion imaging combines the precise catheter and device visualization of fluoroscopy with the soft tissue anatomy and color flow Doppler information afforded by echocardiography in a single image. This allows the interventionalist to perform precise catheter manipulations under fluoroscopy guidance while visualizing critical tissue anatomy provided by echocardiography. However, there are few data available addressing this technology's strengths and limitations in routine clinical practice. The authors provide a critical review of currently available echocardiographic-fluoroscopic fusion imaging for guidance of structural heart interventions to highlight its strengths, limitations, and potential clinical applications and to guide further research into value of this emerging technology. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  18. Current Brachytherapy Quality Assurance Guidance: Does It Meet the Challenges of Emerging Image-Guided Technologies?

    International Nuclear Information System (INIS)

    Williamson, Jeffrey F.

    2008-01-01

    In the past decade, brachytherapy has shifted from the traditional surgical paradigm to more modern three-dimensional image-based planning and delivery approaches. The role of intraoperative and multimodality image-based planning is growing. Published American Association of Physicists in Medicine, American College of Radiology, European Society for Therapeutic Radiology and Oncology, and International Atomic Energy Agency quality assurance (QA) guidelines largely emphasize the QA of planning and delivery devices rather than processes. These protocols have been designed to verify compliance with major performance specifications and are not risk based. With some exceptions, complete and clinically practical guidance exists for sources, QA instrumentation, non-image-based planning systems, applicators, remote afterloading systems, dosimetry, and calibration. Updated guidance is needed for intraoperative imaging systems and image-based planning systems. For non-image-based brachytherapy, the American Association of Physicists in Medicine Task Group reports 56 and 59 provide reasonable guidance on procedure-specific process flow and QA. However, improved guidance is needed even for established procedures such as ultrasound-guided prostate implants. Adaptive replanning in brachytherapy faces unsolved problems similar to that of image-guided adaptive external beam radiotherapy

  19. Image-guidance for surgical procedures

    International Nuclear Information System (INIS)

    Peters, Terry M

    2006-01-01

    Contemporary imaging modalities can now provide the surgeon with high quality three- and four-dimensional images depicting not only normal anatomy and pathology, but also vascularity and function. A key component of image-guided surgery (IGS) is the ability to register multi-modal pre-operative images to each other and to the patient. The other important component of IGS is the ability to track instruments in real time during the procedure and to display them as part of a realistic model of the operative volume. Stereoscopic, virtual- and augmented-reality techniques have been implemented to enhance the visualization and guidance process. For the most part, IGS relies on the assumption that the pre-operatively acquired images used to guide the surgery accurately represent the morphology of the tissue during the procedure. This assumption may not necessarily be valid, and so intra-operative real-time imaging using interventional MRI, ultrasound, video and electrophysiological recordings are often employed to ameliorate this situation. Although IGS is now in extensive routine clinical use in neurosurgery and is gaining ground in other surgical disciplines, there remain many drawbacks that must be overcome before it can be employed in more general minimally-invasive procedures. This review overviews the roots of IGS in neurosurgery, provides examples of its use outside the brain, discusses the infrastructure required for successful implementation of IGS approaches and outlines the challenges that must be overcome for IGS to advance further. (topical review)

  20. Anatomical Variations of Carotid Artery and Optic Nerve in Sphenoid Sinus Using Computerized Tomographic Imaging

    Directory of Open Access Journals (Sweden)

    Nikakhlagh

    2014-12-01

    Full Text Available Background Sphenoid sinus is surrounded by many vital vascular and nervous structures. In more than 20% of patients with chronic sinusitis, involvement of sphenoid sinus has been observed. Besides, sphenoid sinus is an appropriate route to access anterior and middle cranial fossa in surgery. Therefore, it is important to have an adequate knowledge about the contents of sphenoid sinus and its proximity for nasal endoscopy, sinus surgeries and neurosurgeries. Objectives The aim of this study was to study sphenoid sinus proximity with carotid artery and the optic nerve using computerized tomographic imaging. Materials and Methods In this prospective study, computerized tomographic images of sphenoid sinus of patients referred to Imam Khomeini and Apadana hospitals were studied. The images were studied regarding any bulging, as well as not having a bone covering in sphenoid sinus regarding internal carotid artery and optic nerve. Furthermore, unilateralness or bilateralness of their relationships was studied. Results Among 468 coronal and axial CT scan images of sphenoid sinus, 365 (78% showed post-sellar pneumatization and 103 (22% pre-sellar pneumatization. Regarding existence of internal septa, 346 (74% cases showed multiple septation, and the remaining images were reported to have a single septum. According to the reports of CT scan images, the existence of bulging as a result of internal carotid artery and uncovered artery were 4.22% and 5.8% in the right sinus, 4.9% and 5.4% in the left sinus, and 4.34% and 4.6% in both sinuses, respectively. According to the reports of CT scan images, existence of bulging as a result of optic nerve and uncovered nerve were 5.7% and 4.3% in the right sinus, 6% and 5.4% in the left sinus, and 12% and 3.2% in both sinuses, respectively. Conclusions Due to variability of sphenoid sinus pneumatization and the separator blade of the two sinus cavities, careful attention is required during sinus surgery to avoid

  1. Compton scatter imaging: A promising modality for image guidance in lung stereotactic body radiation therapy.

    Science.gov (United States)

    Redler, Gage; Jones, Kevin C; Templeton, Alistair; Bernard, Damian; Turian, Julius; Chu, James C H

    2018-03-01

    Lung stereotactic body radiation therapy (SBRT) requires delivering large radiation doses with millimeter accuracy, making image guidance essential. An approach to forming images of patient anatomy from Compton-scattered photons during lung SBRT is presented. To investigate the potential of scatter imaging, a pinhole collimator and flat-panel detector are used for spatial localization and detection of photons scattered during external beam therapy using lung SBRT treatment conditions (6 MV FFF beam). MCNP Monte Carlo software is used to develop a model to simulate scatter images. This model is validated by comparing experimental and simulated phantom images. Patient scatter images are then simulated from 4DCT data. Experimental lung tumor phantom images have sufficient contrast-to-noise to visualize the tumor with as few as 10 MU (0.5 s temporal resolution). The relative signal intensity from objects of different composition as well as lung tumor contrast for simulated phantom images agree quantitatively with experimental images, thus validating the Monte Carlo model. Scatter images are shown to display high contrast between different materials (lung, water, bone). Simulated patient images show superior (~double) tumor contrast compared to MV transmission images. Compton scatter imaging is a promising modality for directly imaging patient anatomy during treatment without additional radiation, and it has the potential to complement existing technologies and aid tumor tracking and lung SBRT image guidance. © 2018 American Association of Physicists in Medicine.

  2. Tomographic evaluation of a dual-head positron emission tomography system

    International Nuclear Information System (INIS)

    Efthimiou, N; Maistros, S; Tripolitis, X; Panayiotakis, G; Samartzis, A; Loudos, G

    2011-01-01

    In this paper we present the performance evaluation results, in the planar and tomographic modes, of a low-cost positron emission tomography camera dedicated to small-animal imaging. The system consists of two pixelated Lu 2 SiO 5 crystals, two Hamamatsu H8500 position sensitive photomultiplier tubes, fast amplification electronics and an FPGA-USB-based read-out system. The parameters that have been studied are (i) saturation as a function of the head distance and photon acceptance angle, (ii) effect of the number of projections and half or complete head's rotation, (iii) spatial resolution as a function of the head distance, (iv) spatial resolution as a function of acceptance angle, (v) system's sensitivity as a function of these parameters and (vi) performance in small mice imaging. Image reconstruction has been carried out using open source software developed by our group (QSPECT), which is designed mainly for SPECT imaging. The results indicate that the system has a linear response for activities up to at least 2 MBq, which are typical in small-animal imaging. Best tomographic spatial resolution was measured to be ∼2 mm. The system has been found suitable for imaging of small mice both in the planar and tomographic modes

  3. A new method to evaluate image quality of nuclear medicine tomographs

    International Nuclear Information System (INIS)

    Giannone, C.A.; Cabrejas, M.L.; Arashiro, J.A.

    2002-01-01

    Objective: To evaluate the usefulness of a new statistics, the Performance Index (PI), in order to make judgements about diagnostic accuracy of nuclear medicine tomographs (NMT). Methods: A phantom was designed for blind evaluation of device performance. It has 8 cold cylindrical inserts of different diameters. Acquisitions were performed in 40 labs following a defined protocol (under an International Atomic Energy Agency survey). Non-reconstructed set of views were processed and evaluated at a central lab using the same protocol for all the studies. Lesion detection was performed over eye-selected reconstructed slices applying a smoothing filter and a look up table (LUT) with fixed thresholds: counts/pixel = mean ± K . Standard deviation, with K=1,2,3 or >3. The number and location of the inserts was reported by blind observers, afterwards the true and false positive fractions was assessed by another observer. Receiver operating characteristic (ROC) analysis cannot be applied in our experiment where each image with multiple simulated lesions needs to be evaluated. A free-response ROC analysis, developed for observers' performance evaluation, has also flaws. Moreover, our goal was to assess device performance minimising the observer component. A new index, PI, that considers simultaneously the number of true and false positives (TP and FP) was evaluated to categorise NMT. PI is the ratio between the positive predictive value and the sensitivity, expressed as its complement adding a constant to avoid a singularity. Results: The smoothing filter and the selected LUT leads to observers-independent simulated lesion detection. Based on statistical analysis (bootstrapping), it is concluded that the number of observed false positives must be lower than the observed true positives (no. FP < no. TP) to accept an instrument for clinical purposes. Moreover, the number of observed TP must be considered in relation to a minimum tomographic resolution needed to achieve enough

  4. Tomographic PIV: principles and practice

    International Nuclear Information System (INIS)

    Scarano, F

    2013-01-01

    A survey is given of the major developments in three-dimensional velocity field measurements using the tomographic particle image velocimetry (PIV) technique. The appearance of tomo-PIV dates back seven years from the present review (Elsinga et al 2005a 6th Int. Symp. PIV (Pasadena, CA)) and this approach has rapidly spread as a versatile, robust and accurate technique to investigate three-dimensional flows (Arroyo and Hinsch 2008 Topics in Applied Physics vol 112 ed A Schröder and C E Willert (Berlin: Springer) pp 127–54) and turbulence physics in particular. A considerable number of applications have been achieved over a wide range of flow problems, which requires the current status and capabilities of tomographic PIV to be reviewed. The fundamental aspects of the technique are discussed beginning from hardware considerations for volume illumination, imaging systems, their configurations and system calibration. The data processing aspects are of uppermost importance: image pre-processing, 3D object reconstruction and particle motion analysis are presented with their fundamental aspects along with the most advanced approaches. Reconstruction and cross-correlation algorithms, attaining higher measurement precision, spatial resolution or higher computational efficiency, are also discussed. The exploitation of 3D and time-resolved (4D) tomographic PIV data includes the evaluation of flow field pressure on the basis of the flow governing equation. The discussion also covers a-posteriori error analysis techniques. The most relevant applications of tomo-PIV in fluid mechanics are surveyed, covering experiments in air and water flows. In measurements in flow regimes from low-speed to supersonic, most emphasis is given to the complex 3D organization of turbulent coherent structures. (topical review)

  5. Introduction to curved rotary tomographic apparatus 'TOMOREX'

    International Nuclear Information System (INIS)

    Kubota, Kazuo; Shinojima, Masayasu; Kohirasawa, Hideo; Tokui, Mitsuru

    1980-01-01

    In recent years, panorama X-ray photographic method is widely used for the X-ray diagnosis of teeth, jawbones and faces. One type based on the principle of tomography is curved surface rotary tomographic method utilizing fine-gap X-ray beam. With the synchronous rotation of an X-ray tube and a photographic film around a face, describing a U-shaped tomographic plane along a dental arch, an upper or lower jawbone is photographed. In the ''TOMOREX'' belonging to this type, is different tomographic planes are available, so that by selecting any position in advance, the part can be photographed. Furthermore, patients can be subjected to examination as laid on a stretcher. The mechanism and equipment, and the photographic method for eye sockets, cheekbones, upper jaw cavities and stereoscopic images are described. (J.P.N.)

  6. Comparative validation of the radiographic and tomographic measurement of patellar height

    Directory of Open Access Journals (Sweden)

    Marco Antonio Schueda

    2013-09-01

    Full Text Available OBJECTIVE: To evaluate and validate the radiographic measurement of patellar height with computerized tomography scans. METHODS: Measured the patellar height through the lateral radiographic image supported by one foot and sagittal tomographic view of the knee in extension, flexion of 20°, and quadriceps contraction of 40 patients (80 knees, asymptomatic and no history of knee injuries using Insall-Salvati index. There were 20 adult females and 20 adult males. RESULTS: The height patellar index was higher in women of all images taken, in proportion. There was no statistical difference of patellar height index between the radiographics and tomographics images. CONCLUSION: The Insall-Salvati index in females was higher in all cases evaluated. Furthermore, it is possible to measure the patellar height index during tomographic study without distorting the results obtained, using to define the presence of patella alta or patella baja.

  7. Tomographic imaging

    International Nuclear Information System (INIS)

    Das, B.K.; Noreen Norfaraheen Lee Abdullah

    2012-01-01

    Tomography is used to image anatomy of organs as in the case of CT and MRI or image body functions as in the case of SPECT and PET. The theory of reconstruction applies equally well to CT, SPECT and PET with a minor differences. The main difference between SPECT and PET is that SPECT images single photon emitters (radionuclides) which emit normal gamma rays (like Tc-99m), whereas PET images positron emitting radionuclides such as O 15 or F 18 . The word tomography means drawing of the body. Every tomography results in an image of the inside of the body and is represented as a slice. (author)

  8. Active instrumental guidance in interventional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Wildermuth, S.; Erhart, P.; Leung, D.A.; Goehde, S.; Schoenenberger, A.; Debatin, J.F.

    1998-01-01

    Purpose: An active MR-based guidance system for visualisation of invasive instruments is described. Methods: The principle of MR tracking is based on the integration of a miniaturised coil into the tip of the instrument itself. A phantom experiment was designed to demonstrate the localising accuracy of this technique. In [dition, bicompatibility and warming effects were evaluated. Preliminary intravascular applications that were performed in animal experiments under MR guidance included embolisation, vascular occlusion as well as transjugular intrahepatic punctures. Percutaneous biopsies, cholecystostomies and laparoscopic applications were also evaluated with MR tracking. Results: Phantom experiments confirmed an excellent localisation accuracy of MR tracking compared to conventional r[iography. At a field strength of 0.5 T, the temperature increase remained below 2 C. Results of phantom experiments revealed a potential of significant heating dependent on the sequence parameters employed. MR tracking allowed a robust, simultaneously biplanar visualisation of the instrument tips in real time. Based on MR 'ro[ map' images, various intravascular and percutaneous interventions were successfully performed in vivo under MR guidance. Conclusions: MR tracking is a flexible concept permitting monitoring in the guidance of instruments in an MR environment. Various preliminary in vitro and in vivo experiments demonstrate safety, localisation accuracy and feasibility of this biplanar localisation technique in real time. (orig.) [de

  9. Tomographic extreme-ultraviolet spectrographs: TESS.

    Science.gov (United States)

    Cotton, D M; Stephan, A; Cook, T; Vickers, J; Taylor, V; Chakrabarti, S

    2000-08-01

    We describe the system of Tomographic Extreme Ultraviolet (EUV) SpectrographS (TESS) that are the primary instruments for the Tomographic Experiment using Radiative Recombinative Ionospheric EUV and Radio Sources (TERRIERS) satellite. The spectrographs were designed to make high-sensitivity {80 counts/s)/Rayleigh [one Rayleigh is equivalent to 10(6) photons/(4pi str cm(2)s)}, line-of-sight measurements of the oi 135.6- and 91.1-nm emissions suitable for tomographic inversion. The system consists of five spectrographs, four identical nightglow instruments (for redundancy and added sensitivity), and one instrument with a smaller aperture to reduce sensitivity and increase spectral resolution for daytime operation. Each instrument has a bandpass of 80-140 nm with approximately 2- and 1-nm resolution for the night and day instruments, respectively. They utilize microchannel-plate-based two-dimensional imaging detectors with wedge-and-strip anode readouts. The instruments were designed, fabricated, and calibrated at Boston University, and the TERRIERS satellite was launched on 18 May 1999 from Vandenberg Air Force Base, California.

  10. Robotic needle steering: design, modeling, planning, and image guidance

    NARCIS (Netherlands)

    Cowan, Noah J.; Goldberg, Ken; Chirikjian, Gregory S.; Fichtinger, Gabor; Alterovitz, Ron; Reed, Kyle B.; Kallem, Vinutha; Misra, Sarthak; Park, Wooram; Okamura, Allison M.; Rosen, Jacob; Hannaford, Blake; Satava, Richard M.

    2010-01-01

    This chapter describes how advances in needle design, modeling, planning, and image guidance make it possible to steer flexible needles from outside the body to reach specified anatomical targets not accessible using traditional needle insertion methods. Steering can be achieved using a variety of

  11. Image guidance in trans-sphenoidal surgery for giant pituitary adenomas: Luxury or necessity?

    OpenAIRE

    Deepak Agrawal

    2012-01-01

    Background: In spite of availability of image guidance (neuronavigation) at major centers around the world, most trans-sphenoidal surgeries for pituitary adenomas continue to be done under fluoroscopic control. On the other hand, the high mortality and morbidity for giant pituitary adenomas is mainly due to inadequate tumor removal. Aims and Objectives: The objective of this study was to study to utility of image guidance in trans-sphenoidal surgeries for optimizing tumor removal in giant pit...

  12. Application of the FDK algorithm for multi-slice tomographic image reconstruction; Aplicacao do algoritmo FDK para a reconstrucao de imagens tomograficas multicortes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Roberto, E-mail: pcosta@if.usp.b [Universidade de Sao Paulo (IFUSP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear; Araujo, Ericky Caldas de Almeida [Fine Image Technology, Sao Paulo, SP (Brazil)

    2010-08-15

    This work consisted on the study and application of the FDK (Feldkamp- Davis-Kress) algorithm for tomographic image reconstruction using cone-beam geometry, resulting on the implementation of an adapted multi-slice computed tomography system. For the acquisition of the projections, a rotating platform coupled to a goniometer, an X-ray equipment and a digital image detector charge-coupled device type were used. The FDK algorithm was implemented on a computer with a Pentium{sup R} XEON{sup TM} 3.0 processor, which was used for the reconstruction process. Initially, the original FDK algorithm was applied considering only the ideal physical conditions in the measurement process. Then some artifacts corrections related to the projections measurement process were incorporated. The implemented MSCT system was calibrated. A specially designed and manufactured object with a known linear attenuation coefficient distribution ({mu}(r)) was used for this purpose. Finally, the implemented MSCT system was used for multi-slice tomographic reconstruction of an inhomogeneous object, whose distribution {mu}(r) was unknown. Some aspects of the reconstructed images were analyzed to assess the robustness and reproducibility of the system. During the system calibration, a linear relationship between CT number and linear attenuation coefficients of materials was verified, which validate the application of the implemented multi-slice tomographic system for the characterization of linear attenuation coefficients of distinct several objects. (author)

  13. Mobile C-arm cone-beam CT for guidance of spine surgery: Image quality, radiation dose, and integration with interventional guidance

    Energy Technology Data Exchange (ETDEWEB)

    Schafer, S.; Nithiananthan, S.; Mirota, D. J.; Uneri, A.; Stayman, J. W.; Zbijewski, W.; Schmidgunst, C.; Kleinszig, G.; Khanna, A. J.; Siewerdsen, J. H. [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21202 (United States); Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21202 (United States); Siemens Healthcare XP Division, Erlangen (Germany); Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, Maryland 21239 (United States); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21202 and Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2011-08-15

    Purpose: A flat-panel detector based mobile isocentric C-arm for cone-beam CT (CBCT) has been developed to allow intraoperative 3D imaging with sub-millimeter spatial resolution and soft-tissue visibility. Image quality and radiation dose were evaluated in spinal surgery, commonly relying on lower-performance image intensifier based mobile C-arms. Scan protocols were developed for task-specific imaging at minimum dose, in-room exposure was evaluated, and integration of the imaging system with a surgical guidance system was demonstrated in preclinical studies of minimally invasive spine surgery. Methods: Radiation dose was assessed as a function of kilovolt (peak) (80-120 kVp) and milliampere second using thoracic and lumbar spine dosimetry phantoms. In-room radiation exposure was measured throughout the operating room for various CBCT scan protocols. Image quality was assessed using tissue-equivalent inserts in chest and abdomen phantoms to evaluate bone and soft-tissue contrast-to-noise ratio as a function of dose, and task-specific protocols (i.e., visualization of bone or soft-tissues) were defined. Results were applied in preclinical studies using a cadaveric torso simulating minimally invasive, transpedicular surgery. Results: Task-specific CBCT protocols identified include: thoracic bone visualization (100 kVp; 60 mAs; 1.8 mGy); lumbar bone visualization (100 kVp; 130 mAs; 3.2 mGy); thoracic soft-tissue visualization (100 kVp; 230 mAs; 4.3 mGy); and lumbar soft-tissue visualization (120 kVp; 460 mAs; 10.6 mGy) - each at (0.3 x 0.3 x 0.9 mm{sup 3}) voxel size. Alternative lower-dose, lower-resolution soft-tissue visualization protocols were identified (100 kVp; 230 mAs; 5.1 mGy) for the lumbar region at (0.3 x 0.3 x 1.5 mm{sup 3}) voxel size. Half-scan orbit of the C-arm (x-ray tube traversing under the table) was dosimetrically advantageous (prepatient attenuation) with a nonuniform dose distribution ({approx}2 x higher at the entrance side than at isocenter

  14. Achievement report for fiscal 1998. Optical tomographic system; 1998 nendo seika hokokusho. Hikari danso imaging system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    Evaluations were given on spatial resolution and measurement time of an optical tomographic system by using the developed 64-channel time-resolved spectroscopy and an image reconstruction algorithm. With respect to the spatial resolution, the target value of 1 cm was verified from tomographic images of a phantom with a diameter of 10cm, simulating a neonate. The measurement time achieved 20 minutes, being one third of the target value. In installing the equipment at Hokkaido University, speeds of the optical switches and attenuators were increased to have reduced the measurement time to one minute. For installation at Kanagawa Rehabilitation Center, development has been made on a nano-second light pulser, whose average beam quantity has been increased to 40 times, and improvement has been given on the optical switches, the attenuators, and the indication software, by which the measurement time was decreased further by 30 seconds than that at Hokkaido University. In performing the clinical evaluation, the evaluation protocol resolved by the Experiment Evaluation Special Committee was submitted for deliberation at the Medical Welfare Device Clinical Evaluation Committee. Upon having been authorized by the Committee, the clinical evaluations were performed at Hokkaido University and the Kanagawa Rehabilitation Center. (NEDO)

  15. Estimating Single and Multiple Target Locations Using K-Means Clustering with Radio Tomographic Imaging in Wireless Sensor Networks

    Science.gov (United States)

    2015-03-26

    clustering is an algorithm that has been used in data mining applications such as machine learning applications , pattern recognition, hyper-spectral imagery...42 3.7.2 Application of K-means Clustering . . . . . . . . . . . . . . . . . 42 3.8 Experiment Design...Tomographic Imaging WLAN Wireless Local Area Networks WSN Wireless Sensor Network xx ESTIMATING SINGLE AND MULTIPLE TARGET LOCATIONS USING K-MEANS CLUSTERING

  16. Data and Analysis from a Time-Resolved Tomographic Optical Beam Diagnostic

    International Nuclear Information System (INIS)

    Frayer, Daniel K.; Johnson, Douglas; Ekdahl, Carl

    2010-01-01

    An optical tomographic diagnostic instrument developed for the acquisition of high-speed time-resolved images has been fielded at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility at Los Alamos National Laboratory. The instrument was developed for the creation of time histories of electron-beam cross section through the collection of Cerenkov light. Four optical lines of sight optically collapse an image and relay projections via an optical fiber relay to recording instruments; a tomographic reconstruction algorithm creates the time history. Because the instrument may be operated in an adverse environment, it may be operated, adjusted, and calibrated remotely. The instrument was operated over the course of various activities during and after DARHT commissioning, and tomographic reconstructions reported verifiable beam characteristics. Results from the collected data and reconstructions and analysis of the data are discussed.

  17. Estimation of spatial uncertainties of tomographic velocity models

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, M.; Du, Z.; Querendez, E. [SINTEF Petroleum Research, Trondheim (Norway)

    2012-12-15

    This research project aims to evaluate the possibility of assessing the spatial uncertainties in tomographic velocity model building in a quantitative way. The project is intended to serve as a test of whether accurate and specific uncertainty estimates (e.g., in meters) can be obtained. The project is based on Monte Carlo-type perturbations of the velocity model as obtained from the tomographic inversion guided by diagonal and off-diagonal elements of the resolution and the covariance matrices. The implementation and testing of this method was based on the SINTEF in-house stereotomography code, using small synthetic 2D data sets. To test the method the calculation and output of the covariance and resolution matrices was implemented, and software to perform the error estimation was created. The work included the creation of 2D synthetic data sets, the implementation and testing of the software to conduct the tests (output of the covariance and resolution matrices which are not implicitly provided by stereotomography), application to synthetic data sets, analysis of the test results, and creating the final report. The results show that this method can be used to estimate the spatial errors in tomographic images quantitatively. The results agree with' the known errors for our synthetic models. However, the method can only be applied to structures in the model, where the change of seismic velocity is larger than the predicted error of the velocity parameter amplitudes. In addition, the analysis is dependent on the tomographic method, e.g., regularization and parameterization. The conducted tests were very successful and we believe that this method could be developed further to be applied to third party tomographic images.

  18. Cone beam computed tomography image guidance system for a dedicated intracranial radiosurgery treatment unit.

    Science.gov (United States)

    Ruschin, Mark; Komljenovic, Philip T; Ansell, Steve; Ménard, Cynthia; Bootsma, Gregory; Cho, Young-Bin; Chung, Caroline; Jaffray, David

    2013-01-01

    Image guidance has improved the precision of fractionated radiation treatment delivery on linear accelerators. Precise radiation delivery is particularly critical when high doses are delivered to complex shapes with steep dose gradients near critical structures, as is the case for intracranial radiosurgery. To reduce potential geometric uncertainties, a cone beam computed tomography (CT) image guidance system was developed in-house to generate high-resolution images of the head at the time of treatment, using a dedicated radiosurgery unit. The performance and initial clinical use of this imaging system are described. A kilovoltage cone beam CT system was integrated with a Leksell Gamma Knife Perfexion radiosurgery unit. The X-ray tube and flat-panel detector are mounted on a translational arm, which is parked above the treatment unit when not in use. Upon descent, a rotational axis provides 210° of rotation for cone beam CT scans. Mechanical integrity of the system was evaluated over a 6-month period. Subsequent clinical commissioning included end-to-end testing of targeting performance and subjective image quality performance in phantoms. The system has been used to image 2 patients, 1 of whom received single-fraction radiosurgery and 1 who received 3 fractions, using a relocatable head frame. Images of phantoms demonstrated soft tissue contrast visibility and submillimeter spatial resolution. A contrast difference of 35 HU was easily detected at a calibration dose of 1.2 cGy (center of head phantom). The shape of the mechanical flex vs scan angle was highly reproducible and exhibited cone beam CT image guidance system was successfully adapted to a radiosurgery unit. The system is capable of producing high-resolution images of bone and soft tissue. The system is in clinical use and provides excellent image guidance without invasive frames. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Tomographic thallium-201 myocardial perfusion scintigrams after maximal coronary artery vasodilation with intravenous dipyridamole: comparison of qualitative and quantitative approaches

    International Nuclear Information System (INIS)

    Francisco, D.A.; Collins, S.M.; Go, R.T.; Ehrhardt, J.C.; Van Kirk, O.C.; Marcus, M.L.

    1982-01-01

    Eighty-six patients had thallium-201 ( 201 Tl) myocardial perfusion scintigrams after intense coronary artery dilation with i.v. dipyridamole. Tomographic and planar 201 Tl scintigrams were obtained in each patient. Tomographic scintigrams were interpreted using quantitative or visual criteria; planar scintigrams were assessed using visual criteria only. When visual criteria were used, interobserver variability was 40% for tomographic scintigrams and 44% for planar scintigrams. In the 24 patients with normal or nonsignificant CAD, quantitative analysis of the tomograms (range approach) indicated that one of 24 (4%) had a positive image (specificity 96%%); in contrast, when visual criteria were used to interpret the tomographic or planar 201 Tl scintigrams, eight of 24 (33%) had positive scintigrams (specificity 67%). In the 51 abnormal patients, the sensitivity of detecting CAD was 46 of 51 (90%) for tomographic scintigrams interpreted quantitatively, 39 of 51 (76%) for tomographic scintigrams interpreted visually and 41 of 51 (80%) for planar scintigrams assessed visually. The tomographic imaging procedure (quantitative interpretation) also demonstrated a high sensitivity (89%) and specificity (100%) in 28 patients (10 normal and 18 CAD), with a clinical diagnosis of unstable angina pectoris. Overall, the predictive accuracy of an abnormal scintigram with quantitative tomographic imaging (98%) was significantly better (p<0.05) than either qualitative planar or pinhole imaging

  20. Decomposition of time-resolved tomographic PIV

    NARCIS (Netherlands)

    Schmid, P.J.; Violato, D.; Scarano, F.

    2012-01-01

    An experimental study has been conducted on a transitional water jet at a Reynolds number of Re = 5,000. Flow fields have been obtained by means of time-resolved tomographic particle image velocimetry capturing all relevant spatial and temporal scales. The measured threedimensional flow fields have

  1. Use of artificial neural networks in drug and explosive detection through tomographic images with thermal neutrons

    International Nuclear Information System (INIS)

    Ferreira, Francisco J.O.; Crispim, Verginia R.; Silva, Ademir X.

    2009-01-01

    The artificial neural network technique was used to identify drugs and plastic explosives, from a tomography composed by a set of six neutrongraphic projections obtained in real time. Bidimensional tomographic images of samples of drugs, explosives and other materials, when digitally processed, yield the characteristic spectra of each type of material. The information contained in those spectra was then used for ANN training, the best images being obtained when the multilayer perceptron model, the back-propagation training algorithm and the Cross-validation interruption criterion were used. ANN showed to be useful in forecasting presence of drugs and explosives hitting a rate of success above 97 %. (author)

  2. Emerging tomographic methods within the petroleum industry

    International Nuclear Information System (INIS)

    Johansen, Geir Anton

    2013-01-01

    Since industrial process tomography was introduced as a concept almost two decades ago, the considerable progress within a large variety of sensing modalities has to a large extent been technology driven. Industrial tomography applications may be divided into three categories: 1) Laboratory systems, 2) Field equipment for diagnostics and mapping purposes, and 3) Permanently installed systems. Examples on emerging methods on all categories will be presented, either from R and D at the University of Bergen and/or our industrial partners. Most developments are within the first category, where tomographs are used to provide better understanding of various processes such as pipe flow, separators, mixers and reactors. Here tomographic data is most often used to provide better process knowledge, for reference measurements and validation and development of process models, and finally for development for instruments and process equipment. The requirement here may be either high spatial resolution or high temporal resolution, or combinations of these. Tomographic field measurements are applied to either to inspect processes or equipment on a regular base or at faulty or irregular operation, or to map multicomponent systems such petroleum reservoirs, their structure and the distribution gas, oil and water within them. The latter will only be briefly touched upon here. Tomographic methods are increasingly being used for process and equipment diagnostics. The requirements vary and solutions based on repetition of single measurements, such as in column scanning, to full tomographic systems where there is sufficiently space or access. The third category is tomographic instruments that are permanently installed in situ in a process. These need not provide full tomographic images and instruments with fewer views are often preferred to reduce complexity and increase the instrument reliability. (author)

  3. Measurement of facial soft tissues thickness using 3D computed tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ho Gul; Kim, Kee Deog; Shin, Dong Won; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Park, Chang Seo [Yonsei Univ. Hospital, Seoul (Korea, Republic of); Han, Seung Ho [Catholic Univ. of Korea, Seoul (Korea, Republic of)

    2006-03-15

    To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology.

  4. Measurement of facial soft tissues thickness using 3D computed tomographic images

    International Nuclear Information System (INIS)

    Jeong, Ho Gul; Kim, Kee Deog; Shin, Dong Won; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Park, Chang Seo; Han, Seung Ho

    2006-01-01

    To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology

  5. Tomographic spectral imaging: microanalysis in 3D

    International Nuclear Information System (INIS)

    Kotula, P.G.; Keenan, M.R.; Michael, J.R.

    2003-01-01

    Full text: Spectral imaging, where a series of complete x-ray spectra are typically collected from a 2D area, holds great promise for comprehensive near-surface microanalysis. There are however numerous microanalysis problems where 3D chemical information is needed as well. In the SEM, some sort of sectioning (either mechanical or with a focused ion beam (FIB) tool) followed by x-ray mapping has, in the past, been utilized in an attempt to perform 3D microanalysis. Reliance on simple mapping has the potential to miss important chemical features as well as misidentify others. In this paper we will describe the acquisition of serial-section tomographic spectral images (TSI) with a dual-beam FIB/SEM equipped with an EDS system. We will also describe the application of a modified version of our multivariate statistical analysis algorithms to TSIs. Serial sectioning was performed with a FEI DB-235 FIB/SEM. Firstly, the specimen normal was tilted to the optic axis of the FIB column and a trench was milled into the surface of the specimen. A second trench was then milled perpendicular to the first to provide visibility of the entire analysis surface to the x-ray detector. In addition, several fiducial markers were milled into the surface to allow for alignment from slice to slice. The electron column is at an angle of 52 deg to the ion column so the electron beam can 'see' the analysis surface milled by the FIB with no additional specimen tilting or rotation. Likewise the x-ray detector is at a radial angle of 45 deg to the plane of the electron and ion columns (about the electron column) and a take-off-angle of 35 deg with respect to an untilted specimen so it can 'see' the analysis surface as well with no additional sample tilting or rotation. Spectral images were acquired from regions 40 μm wide and 20μm deep for each slice. Approximately 1μm/slice was milled and 10-12 total slices were cut. Spectral images were acquired with a Thermo NORAN Vantage (Digital imaging

  6. Radio tomographic imaging of sporadic-E layers during SEEK-2

    Directory of Open Access Journals (Sweden)

    P. A. Bernhardt

    2005-10-01

    Full Text Available During the SEEK-2 Rocket Campaign in August 2002, a Dual Band Beacon (DBB transmitting to Ground Receivers provided unique data on E-Region electron densities. Information from two rocket beacons and four ground receivers yielded multiple samples of E-region horizontal and vertical variations. The radio beacon measurements were made at four sites (Uchinoura, Tarumizu, Tanegashima, Takazaki in Japan for two rockets (S310-31 and S310-32 launched by the Institute of Space and Aeronautical Science (ISAS. Analysis was completed for four sets of beacon data to provide electron density images of sporadic-E layers. Signals from the two-frequency beacons on the SEEK-2 rockets were processed to yield total electron content (TEC data that was converted into electron density measurements. Wide variations in layer structures were detected. These included horizontal sporadic-E variations, vertical profiles of double, single, and weak layers. The radio beacon measurements were shown to be in agreement with the in-situ SEEK-2 sensors. The first tomographic image of a sporadic-E layer was produced from the data. The rocket beacon technique was shown to be an excellent tool to study sporadic-E layers because absolute TEC accuracy of 0.01 TEC Units can be easily obtained and, with proper receiver placement, electron density images can be produced using computerized ionospheric tomography with better than 1km horizontal and vertical resolution. Keywords. Ionospheric irregularities – Instruments and techniques – Mid-latitude ionosphere

  7. Diagnostic accuracy of multi-slice computed tomographic angiography in the detection of cerebral aneurysms

    International Nuclear Information System (INIS)

    Haghighatkhah, H. R.; Sabouri, S.; Borzouyeh, F.; Bagherzadeh, M. H.; Bakhshandeh, H.; Jalali, A. H.

    2008-01-01

    Multislice computed tomographic angiography is a rapid and minimally invasive method for the detection of intracranial aneurysms. The purpose of this study was to compare Multislice computed tomographic angiography with digital subtraction angiography In the diagnosis of cerebral aneurysms. Patients and Methods: In this cross sectional study we evaluated 111 consecutive patients [42(37.8%) male and 69(62.2%) female], who were admitted under clinical symptoms and signs. suggestive of harboring an intracranial aneurysm by using a four detector Multislice computed tomographic angiography. Then we compared results of Multislice computed tomographic angiography with digital subtraction angiography results as a gold standard method. Digital subtraction angiography was performed by bilateral selective common carotid artery injections and either unilateral or bilateral vertebral artery injections, as necessary. Multislice computed tomographic angiography images were interpreted by one radiologist and digital subtraction angiography was performed by another radiologist who was blinded to the interpretation of the Multislice computed tomographic angiograms. Results: The mean ±S D age of the patients was 49.1±13.6 years (range: 12-84 years). We performed Multislice computed tomographic in 111 and digital subtraction angiography in 85 patients. The sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratio of Multislice computed tomographic angiography, when compared with digital subtraction angiography as the gold standard, were 100%, 90%, 87.5%, 100%, 10 and 0, respectively. Conclusion: Multislice computed tomographic angiography seems to be an accurate and noninvasive imaging modality in the diagnosis of intracranial aneurysms

  8. Reproducibility of temporomandibular joint tomography. Influence of shifted X-ray beam and tomographic focal plane on reproducibility

    International Nuclear Information System (INIS)

    Saito, Masashi

    1999-01-01

    Proper tomographic focal plane and x-ray beam direction are the most important factors to obtain accurate images of the temporomandibular joint (TMJ). In this study, to clarify the magnitude of effect of these two factors on the image quality. We evaluated the reproducibility of tomograms by measuring the distortion when the x-ray beam was shifted from the correct center of the object. The effects of the deviation of the tomographic focal plane on image quality were evaluated by the MTF (Modulation Transfer Function). Two types of tomograms, one the plane type, the other the rotational type were used in this study. A TMJ model was made from Teflon for the purpose of evaluation by shifting the x-ray beam. The x-ray images were obtained by tilting the model from 0 to 10 degrees 2-degree increments. These x-ray images were processed for computer image analysis, and then the distance between condyle and the joint space was measured. To evaluate the influence of the shifted tomographic focal plane on image sharpness, the x-ray images from each setting were analyzed by MTF. To obtain the MTF, ''knife-edge'' made from Pb was used. The images were scanned with a microdensitometer at the central focal plane, and 0, 0.5, 1 mm away respectively. The density curves were analyzed by Fourier analysis and the MTF was calculated. The reproducibility of images became worse by shifting the x-ray beam. This tendency was similar for both tomograms. Object characteristics such as anterior and posterior portion of the joint space affected the deterioration of reproducibility of the tomography. The deviation of the tomographic focal plane also decreased the reproducibility of the x-ray images. The rotational type showed a better MTF, but it became seriously unfavorable with slight changes of the tomographic focal plane. Contrarily, the plane type showed a lower MTF, but the image was stable with shifting of the tomographic focal plane. (author)

  9. A positron emission tomograph designed for 3/4 mm resolution

    International Nuclear Information System (INIS)

    McInytre, J.A.; Allen, R.D.; Aguiar, J.; Paulson, J.T.

    1995-01-01

    Two factors of the design for a positron tomograph affect the magnitude of the tomograph spatial resolution: the gamma ray detector width and the analogue measurement of the scintillator location. In the tomograph design reported here the analogue measurement is eliminated and the detector transaxial width factor is reduced to 3/4 mm. The analogue measurement is eliminated by transmitting the scintillation light from each individual scintillator through optical fibers to four photo-multipliers (PMT's); the identities of the PMT's then provide a digital address for the scintillation location. Plastic scintillators are used to provide enough scintillation light for transmission through the optical fibers. Bonuses from the use of plastic scintillators are first, the reduction of the scintillator dead time to about 10 nsec, second, a large reduction of cross-talk between neighboring scintillators, third, the reduction of resolution loss from off-axis gamma rays and, fourth, the ability to sample the axial image at one-eighth the axial resolution distance of 2.5 mm. The designed tomograph incorporates 20 rings. Two of the 32 tomograph 20-ring modules have been constructed to measure the resolution and other characteristics of the tomographs

  10. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    Wong, S.T.C. [Univ. of California, San Francisco, CA (United States)

    1997-02-01

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a {open_quotes}true 3D screen{close_quotes}. To confine the scope, this presentation will not discuss such approaches.

  11. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    International Nuclear Information System (INIS)

    Wong, S.T.C.

    1997-01-01

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a open-quotes true 3D screenclose quotes. To confine the scope, this presentation will not discuss such approaches

  12. Tomographic imaging of rock conditions ahead of mining using the shearer as a seismic source - A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Luo, X.; King, A.; Van de Werken, M. [CSIRO, Brisbane, Qld. (Australia)

    2009-11-15

    Roof falls due to poor rock conditions in a coal longwall panel may threaten miner's life and cause significant interruption to mine production. There has been a requirement for technologies that are capable of imaging the rock conditions in longwall coal mining, ahead of the working face and without any interruption to production. A feasibility study was carried out to investigate the characteristics of seismic signals generated by the continuous coal cutter (shearer) and recorded by geophone arrays deployed ahead of the working face, for the purpose of seismic tomographic imaging of roof strata condition before mining. Two experiments were conducted at a coal mine using two arrays of geophones. The experiments have demonstrated that the longwall shearer generates strong and low-frequency (similar to 40 Hz) seismic energy that can be adequately detected by geophones deployed in shallow boreholes along the roadways as far as 300 m from the face. Using noise filtering and signal cross correlation techniques, the seismic arrival times associated with the shearer cutting can be reliably determined. It has proved the concept that velocity variations ahead of the face can be mapped out using tomographic techniques while mining is in progress.

  13. What is the value of Image guidance in external beam radiotherapy?

    International Nuclear Information System (INIS)

    Kron, Tomas

    2010-01-01

    Full text: Image guided radiation therapy (lGRT) has become available in many radiotherapy centres in Australia. It is intuitive that frequent imaging of the patient with a modality that identifies the target directly at the time of treatment delivery should benefit patients. However, TGRT is also associated with increased cost for equipment, associated training, quality assurance and imaging time. The Trans Tasman Radiation Oncology Group (TROG) has been contracted by the Australian Commonwealth Department of Health and Ageing (DoHA) to investigate a framework that could be applied to establish a cost/utility assessment of IGRT. The present work aims to develop a study that can test this for daily image guidance of prostate cancer patients. Approach Thirty intermediate risk prostate cancer patients treated at ten or more radiotherapy centres in Australia will be invited to participate. Their treatment as per local practice will not be modified; however two additional treatment plans will be created with margins that would reflect a typical margin appropriate for a treatment delivery with and without daily image guidance. Patients will be stratified for volumetric versus planar orthogonal imaging and for IMRT or conformal approaches. The outcome will be a comparison of dose volume histograms for critical structures based on equal target coverage in all plans.

  14. Tomographic methods in nuclear medicine

    International Nuclear Information System (INIS)

    Ahluwalia, B.D.

    1989-01-01

    This book is a review of the various approaches to tomographic imaging that have been pursued in nuclear medicine. The evolution of single photon emission computed tomography (SPECT) is discussed in detail, and the major classes of instrumentation are represented. A section on positron emission tomography is also included, but is rather brief and may serve only as a general introduction

  15. Image reconstruction for a Positron Emission Tomograph optimized for breast cancer imaging

    International Nuclear Information System (INIS)

    Virador, Patrick R.G.

    2000-01-01

    The author performs image reconstruction for a novel Positron Emission Tomography camera that is optimized for breast cancer imaging. This work addresses for the first time, the problem of fully-3D, tomographic reconstruction using a septa-less, stationary, (i.e. no rotation or linear motion), and rectangular camera whose Field of View (FOV) encompasses the entire volume enclosed by detector modules capable of measuring Depth of Interaction (DOI) information. The camera is rectangular in shape in order to accommodate breasts of varying sizes while allowing for soft compression of the breast during the scan. This non-standard geometry of the camera exacerbates two problems: (a) radial elongation due to crystal penetration and (b) reconstructing images from irregularly sampled data. Packing considerations also give rise to regions in projection space that are not sampled which lead to missing information. The author presents new Fourier Methods based image reconstruction algorithms that incorporate DOI information and accommodate the irregular sampling of the camera in a consistent manner by defining lines of responses (LORs) between the measured interaction points instead of rebinning the events into predefined crystal face LORs which is the only other method to handle DOI information proposed thus far. The new procedures maximize the use of the increased sampling provided by the DOI while minimizing interpolation in the data. The new algorithms use fixed-width evenly spaced radial bins in order to take advantage of the speed of the Fast Fourier Transform (FFT), which necessitates the use of irregular angular sampling in order to minimize the number of unnormalizable Zero-Efficiency Bins (ZEBs). In order to address the persisting ZEBs and the issue of missing information originating from packing considerations, the algorithms (a) perform nearest neighbor smoothing in 2D in the radial bins (b) employ a semi-iterative procedure in order to estimate the unsampled data

  16. Image reconstruction for a Positron Emission Tomograph optimized for breast cancer imaging

    Energy Technology Data Exchange (ETDEWEB)

    Virador, Patrick R.G. [Univ. of California, Berkeley, CA (United States)

    2000-04-01

    The author performs image reconstruction for a novel Positron Emission Tomography camera that is optimized for breast cancer imaging. This work addresses for the first time, the problem of fully-3D, tomographic reconstruction using a septa-less, stationary, (i.e. no rotation or linear motion), and rectangular camera whose Field of View (FOV) encompasses the entire volume enclosed by detector modules capable of measuring Depth of Interaction (DOI) information. The camera is rectangular in shape in order to accommodate breasts of varying sizes while allowing for soft compression of the breast during the scan. This non-standard geometry of the camera exacerbates two problems: (a) radial elongation due to crystal penetration and (b) reconstructing images from irregularly sampled data. Packing considerations also give rise to regions in projection space that are not sampled which lead to missing information. The author presents new Fourier Methods based image reconstruction algorithms that incorporate DOI information and accommodate the irregular sampling of the camera in a consistent manner by defining lines of responses (LORs) between the measured interaction points instead of rebinning the events into predefined crystal face LORs which is the only other method to handle DOI information proposed thus far. The new procedures maximize the use of the increased sampling provided by the DOI while minimizing interpolation in the data. The new algorithms use fixed-width evenly spaced radial bins in order to take advantage of the speed of the Fast Fourier Transform (FFT), which necessitates the use of irregular angular sampling in order to minimize the number of unnormalizable Zero-Efficiency Bins (ZEBs). In order to address the persisting ZEBs and the issue of missing information originating from packing considerations, the algorithms (a) perform nearest neighbor smoothing in 2D in the radial bins (b) employ a semi-iterative procedure in order to estimate the unsampled data

  17. A morphological study of the mandibular molar region using reconstructed helical computed tomographic images

    International Nuclear Information System (INIS)

    Tsuno, Hiroaki; Noguchi, Makoto; Noguchi, Akira; Yoshida, Keiko; Tachinami, Yasuharu

    2010-01-01

    This study investigated the morphological variance in the mandibular molar region using reconstructed helical computed tomographic (CT) images. In addition, we discuss the necessity of CT scanning as part of the preoperative assessment process for dental implantation, by comparing the results with the findings of panoramic radiography. Sixty patients examined using CT as part of the preoperative assessment for dental implantation were analyzed. Reconstructed CT images were used to evaluate the bone quality and cross-sectional bone morphology of the mandibular molar region. The mandibular cortical index (MCI) and X-ray density ratio of this region were assessed using panoramic radiography in order to analyze the correlation between the findings of the CT images and panoramic radiography. CT images showed that there was a decrease in bone quality in cases with high MCI. Cross-sectional CT images revealed that the undercuts on the lingual side in the highly radiolucent areas in the basal portion were more frequent than those in the alveolar portion. This study showed that three-dimensional reconstructed CT images can help to detect variances in mandibular morphology that might be missed by panoramic radiography. In conclusion, it is suggested that CT should be included as an important examination tool before dental implantation. (author)

  18. An index of beam hardening artifact for two-dimensional cone-beam CT tomographic images: establishment and preliminary evaluation

    Science.gov (United States)

    Yuan, Fusong; Lv, Peijun; Yang, Huifang; Wang, Yong; Sun, Yuchun

    2015-07-01

    Objectives: Based on the pixel gray value measurements, establish a beam-hardening artifacts index of the cone-beam CT tomographic image, and preliminarily evaluate its applicability. Methods: The 5mm-diameter metal ball and resin ball were fixed on the light-cured resin base plate respectively, while four vitro molars were fixed above and below the ball, on the left and right respectively, which have 10mm distance with the metal ball. Then, cone beam CT was used to scan the fixed base plate twice. The same layer tomographic images were selected from the two data and imported into the Photoshop software. The circle boundary was built through the determination of the center and radius of the circle, according to the artifact-free images section. Grayscale measurement tools were used to measure the internal boundary gray value G0, gray value G1 and G2 of 1mm and 20mm artifacts outside the circular boundary, the length L1 of the arc with artifacts in the circular boundary, the circumference L2. Hardening artifacts index was set A = (G1 / G0) * 0.5 + (G2 / G1) * 0.4 + (L2 / L1) * 0.1. Then, the A values of metal and resin materials were calculated respectively. Results: The A value of cobalt-chromium alloy material is 1, and resin material is 0. Conclusion: The A value reflects comprehensively the three factors of hardening artifacts influencing normal oral tissue image sharpness of cone beam CT. The three factors include relative gray value, the decay rate and range of artifacts.

  19. Reconstruction of computed tomographic image from a few x-ray projections by means of accelerative gradient method

    International Nuclear Information System (INIS)

    Kobayashi, Fujio; Yamaguchi, Shoichiro

    1982-01-01

    A method of the reconstruction of computed tomographic images was proposed to reduce the exposure dose to X-ray. The method is the small number of X-ray projection method by accelerative gradient method. The procedures of computation are described. The algorithm of these procedures is simple, the convergence of the computation is fast, and the required memory capacity is small. Numerical simulation was carried out to conform the validity of this method. A sample of simple shape was considered, projection data were given, and the images were reconstructed from 6 views. Good results were obtained, and the method is considered to be useful. (Kato, T.)

  20. Tomographic X-ray apparatus for the production of transverse layer images

    International Nuclear Information System (INIS)

    Liebetruth, R.

    1984-01-01

    In an extension of the utility of rotary scan tomographic x-ray apparatus, the apparatus is locked in a fixed angular relationship and the patient support is automatically advanced in small longitudinal increments relative to the angularly fixed scanner, the scanner being pulsed in synchronism with the longitudinal steps to produce successive sets of transmittance readings defining a radiographic shadow image having a substantial longitudinal extent. The stored sets of readings may be reproduced on a conventional television display unit. Advantageously, the scanner may present a fan-type beam which in a fixed angular relationship to the patient still scans a substantial portion of the patient cross section, the x-ray source or sources being pulsed at successive longitudinal positions of the patient relative to the scanning apparatus, and the successive sets of readings being utilized for on line display of a shadow radiograph covering the desired longitudinal extent

  1. Computed tomographic study of 50 patients with hypodense hepatic injuries in childhood

    International Nuclear Information System (INIS)

    Pereira, Ines Minniti Rodrigues; Alvares, Beatriz Regina; Baracat, Jamal; Martins, Daniel Lahan; Pereira, Ricardo Minniti Rodrigues

    2006-01-01

    Objective: To describe the different tomographic findings in hypodense hepatic lesions in children and its differential diagnosis. Materials and methods: computed tomographic studies were obtained from 50 patients (age range: 0-16 years) with low-density liver lesions previously diagnosed by ultrasound. Images were made before and after administration of intravenous contrast medium. Image findings were analyzed and afterwards correlated with anatomopathological diagnosis. Results: forty-seven of 50 cases were confirmed, 30 by anatomopathological diagnosis. Most of then were benign lesions, hemangioma in 20%. Such lesions presented a homogeneous contrast absorption, mainly at the delayed phase, differing from malignant lesions. Metastasis was the most frequently found malignant lesion (18%). Conclusion: computed tomographic study is of great value in complementing the diagnosis of hypodense hepatic lesions in children, and must follow ultrasound diagnosis as a routine procedure. (author)

  2. Linear analysis of rotationally invariant, radially variant tomographic imaging systems

    International Nuclear Information System (INIS)

    Huesmann, R.H.

    1990-01-01

    This paper describes a method to analyze the linear imaging characteristics of rotationally invariant, radially variant tomographic imaging systems using singular value decomposition (SVD). When the projection measurements from such a system are assumed to be samples from independent and identically distributed multi-normal random variables, the best estimate of the emission intensity is given by the unweighted least squares estimator. The noise amplification of this estimator is inversely proportional to the singular values of the normal matrix used to model projection and backprojection. After choosing an acceptable noise amplification, the new method can determine the number of parameters and hence the number of pixels that should be estimated from data acquired from an existing system with a fixed number of angles and projection bins. Conversely, for the design of a new system, the number of angles and projection bins necessary for a given number of pixels and noise amplification can be determined. In general, computing the SVD of the projection normal matrix has cubic computational complexity. However, the projection normal matrix for this class of rotationally invariant, radially variant systems has a block circulant form. A fast parallel algorithm to compute the SVD of this block circulant matrix makes the singular value analysis practical by asymptotically reducing the computation complexity of the method by a multiplicative factor equal to the number of angles squared

  3. The 3D tomographic image reconstruction software for prompt-gamma measurement of the boron neutron capture therapy

    International Nuclear Information System (INIS)

    Morozov, Boris; Auterinen, Iiro; Kotiluoto, Petri; Kortesniemi, Mika

    2006-01-01

    A tomographic imaging system based on the spatial distribution measurement of the neutron capture reaction during Boron Neutron Capture Therapy (BNCT) would be very useful for clinical purpose. Using gamma-detectors in a 2D-panel, boron neutron capture and hydrogen neutron capture gamma-rays emitted by the neutron irradiated region can be detected, and an image of the neutron capture events can be reconstructed. A 3D reconstruction software package has been written to support the development of a 3D prompt-gamma tomographic system. The package consists of three independent modules: phantom generation, reconstruction and evaluation modules. The reconstruction modules are based on algebraic approach of the iterative reconstruction algorithm (ART), and on the maximum likelihood estimation method (ML-EM). In addition to that, two subsets of the ART, the simultaneous iterative reconstruction technique (SIRT) and the component averaging algorithms (CAV) have been included to the package employing parallel codes for multiprocessor architecture. All implemented algorithms use two different field functions for the reconstruction of the region. One is traditional voxel function, another is, so called, blob function, smooth spherically symmetric generalized Kaiser-Bessel function. The generation module provides the phantom and projections with background by tracing the prompt gamma-rays for a given scanner geometry. The evaluation module makes statistical comparisons between the generated and reconstructed images, and provides figure-of-merit (FOM) values for the applied reconstruction algorithms. The package has been written in C language and tested under Linux and Windows platforms. The simple graphical user interface (GUI) is used for command execution and visualization purposed. (author)

  4. A detailed comparison of single-camera light-field PIV and tomographic PIV

    Science.gov (United States)

    Shi, Shengxian; Ding, Junfei; Atkinson, Callum; Soria, Julio; New, T. H.

    2018-03-01

    This paper conducts a comprehensive study between the single-camera light-field particle image velocimetry (LF-PIV) and the multi-camera tomographic particle image velocimetry (Tomo-PIV). Simulation studies were first performed using synthetic light-field and tomographic particle images, which extensively examine the difference between these two techniques by varying key parameters such as pixel to microlens ratio (PMR), light-field camera Tomo-camera pixel ratio (LTPR), particle seeding density and tomographic camera number. Simulation results indicate that the single LF-PIV can achieve accuracy consistent with that of multi-camera Tomo-PIV, but requires the use of overall greater number of pixels. Experimental studies were then conducted by simultaneously measuring low-speed jet flow with single-camera LF-PIV and four-camera Tomo-PIV systems. Experiments confirm that given a sufficiently high pixel resolution, a single-camera LF-PIV system can indeed deliver volumetric velocity field measurements for an equivalent field of view with a spatial resolution commensurate with those of multi-camera Tomo-PIV system, enabling accurate 3D measurements in applications where optical access is limited.

  5. Three-dimensional DNA image cytometry by optical projection tomographic microscopy for early cancer diagnosis.

    Science.gov (United States)

    Agarwal, Nitin; Biancardi, Alberto M; Patten, Florence W; Reeves, Anthony P; Seibel, Eric J

    2014-04-01

    Aneuploidy is typically assessed by flow cytometry (FCM) and image cytometry (ICM). We used optical projection tomographic microscopy (OPTM) for assessing cellular DNA content using absorption and fluorescence stains. OPTM combines some of the attributes of both FCM and ICM and generates isometric high-resolution three-dimensional (3-D) images of single cells. Although the depth of field of the microscope objective was in the submicron range, it was extended by scanning the objective's focal plane. The extended depth of field image is similar to a projection in a conventional x-ray computed tomography. These projections were later reconstructed using computed tomography methods to form a 3-D image. We also present an automated method for 3-D nuclear segmentation. Nuclei of chicken, trout, and triploid trout erythrocyte were used to calibrate OPTM. Ratios of integrated optical densities extracted from 50 images of each standard were compared to ratios of DNA indices from FCM. A comparison of mean square errors with thionin, hematoxylin, Feulgen, and SYTOX green was done. Feulgen technique was preferred as it showed highest stoichiometry, least variance, and preserved nuclear morphology in 3-D. The addition of this quantitative biomarker could further strengthen existing classifiers and improve early diagnosis of cancer using 3-D microscopy.

  6. Industrial dynamic tomographic reconstruction; Reconstrucao tomografica dinamica industrial

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Eric Ferreira de

    2016-07-01

    The state of the art methods applied to industrial processes is currently based on the principles of classical tomographic reconstructions developed for tomographic patterns of static distributions, or is limited to cases of low variability of the density distribution function of the tomographed object. Noise and motion artifacts are the main problems caused by a mismatch in the data from views acquired in different instants. All of these add to the known fact that using a limited amount of data can result in the presence of noise, artifacts and some inconsistencies with the distribution under study. One of the objectives of the present work is to discuss the difficulties that arise from implementing reconstruction algorithms in dynamic tomography that were originally developed for static distributions. Another objective is to propose solutions that aim at reducing a temporal type of information loss caused by employing regular acquisition systems to dynamic processes. With respect to dynamic image reconstruction it was conducted a comparison between different static reconstruction methods, like MART and FBP, when used for dynamic scenarios. This comparison was based on a MCNPx simulation as well as an analytical setup of an aluminum cylinder that moves along the section of a riser during the process of acquisition, and also based on cross section images from CFD techniques. As for the adaptation of current tomographic acquisition systems for dynamic processes, this work established a sequence of tomographic views in a just-in-time fashion for visualization purposes, a form of visually disposing density information as soon as it becomes amenable to image reconstruction. A third contribution was to take advantage of the triple color channel necessary to display colored images in most displays, so that, by appropriately scaling the acquired values of each view in the linear system of the reconstruction, it was possible to imprint a temporal trace into the regularly

  7. New techniques for resolution enhancement of 3D x-ray tomographic imaging from incomplete data

    International Nuclear Information System (INIS)

    Vengrinovich, V.; Zolotarev, S.; Denkevich, Y.; Tillack, G.-R.

    2004-01-01

    Accurate evaluation of dimensions directly from tomographic images, restored from only few x-ray projections, made in a limited observation sector, is considered exploiting pipes wall thickness assessment like a typical example. Both experiments and simulations are used to extract main errors sources. It is taken from as known, that neglecting of the scattered radiation and beam hardening effects results in image blurring, strong artifacts and finally inaccurate sizing. The computerized technique is developed to simulate the contribution of scattered radiation and beam hardening for the purpose of their further extraction from projected data. After those accompanying effects extraction the iterative Bayesian techniques are applied to reconstruct images from the projections, using volumetric and/or shell representation of the objects like pipes. The achieved error of virtual pipe wall thickness assessment from 3D images can be as small as 300μk comparing to 1mm provided by modern techniques. Finally the conclusion was drawn that standard projection techniques using X- or Gamma rays in combination with X-ray film or imaging plates can be applied for the data acquisition to reconstruct finally wall thickness profiles in an in-field environment. (author)

  8. Morphologic analysis of Japanese adult sacroiliac joint using computed tomographic images

    International Nuclear Information System (INIS)

    Pan, Xuanchao; Takayama, Akinori; Shibata, Yasuaki; Ito, Hiromoto

    2003-01-01

    The purpose of this study was to study the relationship of angles in adult sacroiliac joints (SJ) with laterality, age, gender, degeneration, childbearing in different locations. The study was performed in 92 healthy Japanese adult volunteers (46 males and 46 females, aged 21∼86 years) who had no low back complaints. Axial computed tomographic (CT) images were obtained using an X-VIGOR apparatus (Toshiba Medical Inc. Japan). The angle measurements were taken directly using soft National Institutes of Health (NIH) Image 1.61 (Scion Inc. USA). We examined possible factors. Statistical evaluation was calculated using t-test by soft SPSS (SPSS Inc. Japan). Our findings indicated that SJ angles had no relationships with laterality, gender. But from upper part to lower part, the average of SJ angle was 7.61 deg±8.7 deg, 5.16 deg±7.3 deg, -0.85 deg±7.3 deg respectively in the left and 6.56 deg±9.4 deg, 4.10 deg±7.2 deg, -2.30 deg±7.0 deg in the right. The difference is significant between lower part and upper-middle part (P<0.05). Our results provided new anatomic and morphological data for better understandings of SJ in the clinic work. (author)

  9. Wide-band antenna design for use in minimal-scan, microwave tomographic imaging

    Science.gov (United States)

    Klaser, Jacob

    Microwave tomography is widely used in biomedical imaging and nondestructive evaluation of dielectric materials. A novel microwave tomography system that uses an electrically-conformable mirror to steer the incident energy for producing multi-view projection data is being developed in the Non-Destructive Evaluation Laboratory (NDEL). Such a system will have a significant advantage over existing tomography systems in terms of simplicity of design and operation, particularly when there is limited-access of the structure that is being imaged. The major components of a mirror-based tomography system are the source mirror assembly, and a receiver array for capturing the multi-view projection data. This thesis addresses the design and development of the receiver array. This imaging array features balanced, anti-podal Vivaldi antennas, which offer large bandwidth, high gain and a compact size. From the simulations, as well as the experimental results for the antenna, the return loss (S 11) is below -10dB for the range from 2.2GHz to 8.2GHz, and the gain is measured to be near 6dB. The data gathered from the receiver array is then run through MATLAB code for tomographic reconstruction using the Filtered Back-Propagation algorithm from limited-view projections. Initial results of reconstruction from the measured data shows the feasibility of the approach, but a significant challenge remains in interpolating the data for a limited number of receiving antenna elements and removing noise from the reconstructed image.

  10. 3D velocity measurements in a premixed flame by tomographic PIV

    International Nuclear Information System (INIS)

    Tokarev, M P; Sharaborin, D K; Lobasov, A S; Chikishev, L M; Dulin, V M; Markovich, D M

    2015-01-01

    Tomographic particle image velocimetry (PIV) has become a standard tool for 3D velocity measurements in non-reacting flows. However, the majority of the measurements in flows with combustion are limited to small resolved depth compared to the size of the field of view (typically 1 : 10). The limitations are associated with inhomogeneity of the volume illumination and the non-uniform flow seeding, the optical distortions and errors in the 3D calibration, and the unwanted flame luminosity. In the present work, the above constraints were overcome for the tomographic PIV experiment in a laminar axisymmetric premixed flame. The measurements were conducted for a 1 : 1 depth-to-size ratio using a system of eight CCD cameras and a 200 mJ pulsed laser. The results show that camera calibration based on the triangulation of the tracer particles in the non-reacting conditions provided reliable accuracy for the 3D image reconstruction in the flame. The modification of the tomographic reconstruction allowed a posteriori removal of unwanted bright objects, which were located outside of the region of interest but affected the reconstruction quality. This study reports on a novel experience for the instantaneous 3D velocimetry in laboratory-scale flames by using tomographic PIV. (paper)

  11. In vivo tomographic imaging with fluorescence and MRI using tumor-targeted dual-labeled nanoparticles

    Directory of Open Access Journals (Sweden)

    Zhang Y

    2013-12-01

    Full Text Available Yue Zhang,1 Bin Zhang,1 Fei Liu,1,2 Jianwen Luo,1,3 Jing Bai1 1Department of Biomedical Engineering, School of Medicine, 2Tsinghua-Peking Center for Life Sciences, 3Center for Biomedical Imaging Research, Tsinghua University, Beijing, People's Republic of China Abstract: Dual-modality imaging combines the complementary advantages of different modalities, and offers the prospect of improved preclinical research. The combination of fluorescence imaging and magnetic resonance imaging (MRI provides cross-validated information and direct comparison between these modalities. Here, we report on the application of a novel tumor-targeted, dual-labeled nanoparticle (NP, utilizing iron oxide as the MRI contrast agent and near infrared (NIR dye Cy5.5 as the fluorescent agent. Results of in vitro experiments verified the specificity of the NP to tumor cells. In vivo tumor targeting and uptake of the NPs in a mouse model were visualized by fluorescence and MR imaging collected at different time points. Quantitative analysis was carried out to evaluate the efficacy of MRI contrast enhancement. Furthermore, tomographic images were also acquired using both imaging modalities and cross-validated information of tumor location and size between these two modalities was revealed. The results demonstrate that the use of dual-labeled NPs can facilitate the dual-modal detection of tumors, information cross-validation, and direct comparison by combing fluorescence molecular tomography (FMT and MRI. Keywords: dual-modality, fluorescence molecular tomography (FMT, magnetic resonance imaging (MRI, nanoparticle

  12. Computed Tomographic Perfusion Improves Diagnostic Power of Coronary Computed Tomographic Angiography in Women

    DEFF Research Database (Denmark)

    Penagaluri, Ashritha; Higgins, Angela Y.; Vavere, Andrea L

    2016-01-01

    laboratories. Prevalence of flow-limiting CAD defined by invasive coronary angiography equal to 50% or greater with an associated single-photon emission computed tomography myocardial perfusion imaging defect was 45% (114/252) and 23% (30/129) in males and females, respectively. Patient-based diagnostic......Background-Coronary computed tomographic angiography (CTA) and myocardial perfusion imaging (CTP) is a validated approach for detection and exclusion of flow-limiting coronary artery disease (CAD), but little data are available on gender-specific performance of these modalities. In this study, we...... aimed to evaluate the diagnostic accuracy of combined coronary CTA and CTP in detecting flow-limiting CAD in women compared with men.  Methods and Results-Three hundred and eighty-one patients who underwent both CTA-CTP and single-photon emission computed tomography myocardial perfusion imaging...

  13. Heidelberg Retina Tomograph for the Detection of Glaucoma

    Directory of Open Access Journals (Sweden)

    Barbara Cvenkel

    2012-06-01

    Full Text Available Heidelberg Retina Tomograph (HRT is a confocal scanning laser ophthalmoscope which acquires and analyzes 3-dimensional images of the optic nerve head. The latest instrument HRT3 includes software with larger ethinic-specific normative database. This review summarizes relevant published literature on HRT in diagnosing glaucoma, detecting glaucoma progression, the diagnostic accuracy of HRT among other imaging devices and its role in clinical practice.

  14. On the feasibility of tomographic-PIV with low pulse energy illumination in a lifted turbulent jet flame

    Science.gov (United States)

    Boxx, I.; Carter, C. D.; Meier, W.

    2014-08-01

    Tomographic particle image velocimetry (tomographic-PIV) is a recently developed measurement technique used to acquire volumetric velocity field data in liquid and gaseous flows. The technique relies on line-of-sight reconstruction of the rays between a 3D particle distribution and a multi-camera imaging system. In a turbulent flame, however, index-of-refraction variations resulting from local heat-release may inhibit reconstruction and thereby render the technique infeasible. The objective of this study was to test the efficacy of tomographic-PIV in a turbulent flame. An additional goal was to determine the feasibility of acquiring usable tomographic-PIV measurements in a turbulent flame at multi-kHz acquisition rates with current-generation laser and camera technology. To this end, a setup consisting of four complementary metal oxide semiconductor cameras and a dual-cavity Nd:YAG laser was implemented to test the technique in a lifted turbulent jet flame. While the cameras were capable of kHz-rate image acquisition, the laser operated at a pulse repetition rate of only 10 Hz. However, use of this laser allowed exploration of the required pulse energy and thus power for a kHz-rate system. The imaged region was 29 × 28 × 2.7 mm in size. The tomographic reconstruction of the 3D particle distributions was accomplished using the multiplicative algebraic reconstruction technique. The results indicate that volumetric velocimetry via tomographic-PIV is feasible with pulse energies of 25 mJ, which is within the capability of current-generation kHz-rate diode-pumped solid-state lasers.

  15. Diagnosis of Alzheimer's disease and multiple infarct dementia by tomographic imaging of iodine-123 IMP

    International Nuclear Information System (INIS)

    Cohen, M.B.; Graham, L.S.; Lake, R.

    1986-01-01

    Tomographic imaging of the brain was performed using a rotating slant hole collimator and [ 123 I]N-isopropyl p-iodoamphetamine (IMP) in normal subjects (n = 6) and patients with either Alzheimer's disease (n = 5) or multiple infarct dementia (n = 3). Four blinded observers were asked to make a diagnosis from the images. Normal subjects and patients with multiple infarct dementia were correctly identified. Alzheimer's disease was diagnosed in three of the five patients with this disease. One patient with early Alzheimer's disease was classified as normal by two of the four observers. Another patient with Alzheimer's disease had an asymmetric distribution of IMP and was incorrectly diagnosed as multiple infarct dementia by all four observers. Limited angle tomography of the cerebral distribution of 123 I appears to be a useful technique for the evaluation of demented patients

  16. Evaluation of alignment error due to a speed artifact in stereotactic ultrasound image guidance

    International Nuclear Information System (INIS)

    Salter, Bill J; Wang, Brian; Szegedi, Martin W; Rassiah-Szegedi, Prema; Shrieve, Dennis C; Cheng, Roger; Fuss, Martin

    2008-01-01

    Ultrasound (US) image guidance systems used in radiotherapy are typically calibrated for soft tissue applications, thus introducing errors in depth-from-transducer representation when used in media with a different speed of sound propagation (e.g. fat). This error is commonly referred to as the speed artifact. In this study we utilized a standard US phantom to demonstrate the existence of the speed artifact when using a commercial US image guidance system to image through layers of simulated body fat, and we compared the results with calculated/predicted values. A general purpose US phantom (speed of sound (SOS) = 1540 m s -1 ) was imaged on a multi-slice CT scanner at a 0.625 mm slice thickness and 0.5 mm x 0.5 mm axial pixel size. Target-simulating wires inside the phantom were contoured and later transferred to the US guidance system. Layers of various thickness (1-8 cm) of commercially manufactured fat-simulating material (SOS = 1435 m s -1 ) were placed on top of the phantom to study the depth-related alignment error. In order to demonstrate that the speed artifact is not caused by adding additional layers on top of the phantom, we repeated these measurements in an identical setup using commercially manufactured tissue-simulating material (SOS = 1540 m s -1 ) for the top layers. For the fat-simulating material used in this study, we observed the magnitude of the depth-related alignment errors resulting from the speed artifact to be 0.7 mm cm -1 of fat imaged through. The measured alignment errors caused by the speed artifact agreed with the calculated values within one standard deviation for all of the different thicknesses of fat-simulating material studied here. We demonstrated the depth-related alignment error due to the speed artifact when using US image guidance for radiation treatment alignment and note that the presence of fat causes the target to be aliased to a depth greater than it actually is. For typical US guidance systems in use today, this will

  17. Evaluation of alignment error due to a speed artifact in stereotactic ultrasound image guidance.

    Science.gov (United States)

    Salter, Bill J; Wang, Brian; Szegedi, Martin W; Rassiah-Szegedi, Prema; Shrieve, Dennis C; Cheng, Roger; Fuss, Martin

    2008-12-07

    Ultrasound (US) image guidance systems used in radiotherapy are typically calibrated for soft tissue applications, thus introducing errors in depth-from-transducer representation when used in media with a different speed of sound propagation (e.g. fat). This error is commonly referred to as the speed artifact. In this study we utilized a standard US phantom to demonstrate the existence of the speed artifact when using a commercial US image guidance system to image through layers of simulated body fat, and we compared the results with calculated/predicted values. A general purpose US phantom (speed of sound (SOS) = 1540 m s(-1)) was imaged on a multi-slice CT scanner at a 0.625 mm slice thickness and 0.5 mm x 0.5 mm axial pixel size. Target-simulating wires inside the phantom were contoured and later transferred to the US guidance system. Layers of various thickness (1-8 cm) of commercially manufactured fat-simulating material (SOS = 1435 m s(-1)) were placed on top of the phantom to study the depth-related alignment error. In order to demonstrate that the speed artifact is not caused by adding additional layers on top of the phantom, we repeated these measurements in an identical setup using commercially manufactured tissue-simulating material (SOS = 1540 m s(-1)) for the top layers. For the fat-simulating material used in this study, we observed the magnitude of the depth-related alignment errors resulting from the speed artifact to be 0.7 mm cm(-1) of fat imaged through. The measured alignment errors caused by the speed artifact agreed with the calculated values within one standard deviation for all of the different thicknesses of fat-simulating material studied here. We demonstrated the depth-related alignment error due to the speed artifact when using US image guidance for radiation treatment alignment and note that the presence of fat causes the target to be aliased to a depth greater than it actually is. For typical US guidance systems in use today, this will

  18. Development and application of a tomographic model from CT images for calculating internal dose to a pregnant woman

    International Nuclear Information System (INIS)

    Shi Chengyu

    2004-01-01

    Assessment of radiation dose and possible risk to a pregnant woman and her fetus is an important task in radiation protection. Although stylized models for male and female patients of different ages have been developed, tomographic models for pregnant women have not been developed to date. This dissertation presents an effort to construct a partial-body model of a pregnant woman from a set of CT images. The patient was 30-weeks pregnant, and the CT scan covered the portion of the body from above liver to below pubic symphysis in 70 slices, each 7 mm thick. The image resolution was 512x512 pixels in a 48 cmx48 cm field. The images were carefully segmented to identify 34 organs and tissues. It has been found that the masses are different from the Reference Woman. The characteristics of the resulting model are discussed and compared with one existing stylized mathematical model for pregnant women. Based on this tomographic model, a Monte Carlo code, EGS4-VLSI, was used to derive specific absorbed fractions. Monoenergetic and isotropic photon and electron emitters distributed in different source organs were assumed and the energies ranged from 10 keV to 4 MeV for photons and from 100 keV to 4 MeV for electrons. The results for high energy (>50 keV) photons showed general agreement with previous studies, however, the results for lower energy (<50 keV) photons showed differences of up to several hundred percent for some source and target organs. For electron results, several tens of percent differences were found. Those differences can be explained by mass differences and the relative geometry differences between source and target organs. In summary, the stylized models for pregnant women are satisfactory for a very large size patient for most of the photon energies (between 50 keV and 4 MeV). However, a tomographic model has to be used to obtain acceptable dose assessments for electrons. The newly calculated SAF data set can provide the nuclear medicine dosimetry field

  19. Potential of image-guidance, gating and real-time tracking to improve accuracy in pulmonary stereotactic body radiotherapy

    International Nuclear Information System (INIS)

    Guckenberger, Matthias; Krieger, Thomas; Richter, Anne; Baier, Kurt; Wilbert, Juergen; Sweeney, Reinhart A.; Flentje, Michael

    2009-01-01

    Purpose: To evaluate the potential of image-guidance, gating and real-time tumor tracking to improve accuracy in pulmonary stereotactic body radiotherapy (SBRT). Materials and methods: Safety margins for compensation of inter- and intra-fractional uncertainties of the target position were calculated based on SBRT treatments of 43 patients with pre- and post-treatment cone-beam CT imaging. Safety margins for compensation of breathing motion were evaluated for 17 pulmonary tumors using respiratory correlated CT, model-based segmentation of 4D-CT images and voxel-based dose accumulation; the target in the mid-ventilation position was the reference. Results: Because of large inter-fractional base-line shifts of the tumor, stereotactic patient positioning and image-guidance based on the bony anatomy required safety margins of 12 mm and 9 mm, respectively. Four-dimensional image-guidance targeting the tumor itself and intra-fractional tumor tracking reduced margins to <5 mm and <3 mm, respectively. Additional safety margins are required to compensate for breathing motion. A quadratic relationship between tumor motion and margins for motion compensation was observed: safety margins of 2.4 mm and 6 mm were calculated for compensation of 10 mm and 20 mm motion amplitudes in cranio-caudal direction, respectively. Conclusion: Four-dimensional image-guidance with pre-treatment verification of the target position and online correction of errors reduced safety margins most effectively in pulmonary SBRT.

  20. Assessment of Normal Eyeball Protrusion Using Computed Tomographic Imaging and Three-Dimensional Reconstruction in Korean Adults.

    Science.gov (United States)

    Shin, Kang-Jae; Gil, Young-Chun; Lee, Shin-Hyo; Kim, Jeong-Nam; Yoo, Ja-Young; Kim, Soon-Heum; Choi, Hyun-Gon; Shin, Hyun Jin; Koh, Ki-Seok; Song, Wu-Chul

    2017-01-01

    The aim of the present study was to assess normal eyeball protrusion from the orbital rim using two- and three-dimensional images and demonstrate the better suitability of CT images for assessment of exophthalmos. The facial computed tomographic (CT) images of Korean adults were acquired in sagittal and transverse views. The CT images were used in reconstructing three-dimensional volume of faces using computer software. The protrusion distances from orbital rims and the diameters of eyeballs were measured in the two views of the CT image and three-dimensional volume of the face. Relative exophthalmometry was calculated by the difference in protrusion distance between the right and left sides. The eyeball protrusion was 4.9 and 12.5 mm in sagittal and transverse views, respectively. The protrusion distances were 2.9 mm in the three-dimensional volume of face. There were no significant differences between right and left sides in the degree of protrusion, and the difference was within 2 mm in more than 90% of the subjects. The results of the present study will provide reliable criteria for precise diagnosis and postoperative monitoring using CT imaging of diseases such as thyroid-associated ophthalmopathy and orbital tumors.

  1. The CDD system in computed tomographic diagnosis of diverticular disease

    International Nuclear Information System (INIS)

    Pustelnik, Daniel; Elsholtz, Fabian Henry Juergen; Hamm, Bernd; Niehues, Stefan Markus; Bojarski, Christian

    2017-01-01

    Purpose cation in computed tomographic diagnosis and briefly recapitulates its targeted advantages over preliminary systems. Primarily, application of the CDD in computed tomography diagnostics is described. Differences with respect to the categories of the older systems are pointed out on the level of each CDD type using imaging examples. The presented images are derived from our institute according to the S2k criteria. Literature was researched on PubMed. Results The CDD constitutes an improvement compared to older systems for categorizing the stages of diverticular disease. It provides more discriminatory power on the descriptive-morphological level and defines as well as differentiates more courses of the disease. Furthermore, the categories translate more directly into state-of-the-art decision-making concerning hospitalization and therapy. The CDD should be applied routinely in the computed tomographic diagnosis of diverticular disease. Typical imaging patterns are presented.

  2. Tomographic Particle Image Velocimetry using Smartphones and Colored Shadows

    KAUST Repository

    Aguirre-Pablo, Andres A.

    2017-06-12

    We demonstrate the viability of using four low-cost smartphone cameras to perform Tomographic PIV. We use colored shadows to imprint two or three different time-steps on the same image. The back-lighting is accomplished with three sets of differently-colored pulsed LEDs. Each set of Red, Green & Blue LEDs is shone on a diffuser screen facing each of the cameras. We thereby record the RGB-colored shadows of opaque suspended particles, rather than the conventionally used scattered light. We subsequently separate the RGB color channels, to represent the separate times, with preprocessing to minimize noise and cross-talk. We use commercially available Tomo-PIV software for the calibration, 3-D particle reconstruction and particle-field correlations, to obtain all three velocity components in a volume. Acceleration estimations can be done thanks to the triple pulse illumination. Our test flow is a vortex ring produced by forcing flow through a circular orifice, using a flexible membrane, which is driven by a pressurized air pulse. Our system is compared to a commercial stereoscopic PIV system for error estimations. We believe this proof of concept experiment will make this technique available for education, industry and scientists for a fraction of the hardware cost needed for traditional Tomo-PIV.

  3. High resolution tomographic instrument development

    International Nuclear Information System (INIS)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational

  4. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  5. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  6. A distribution-based parametrization for improved tomographic imaging of solute plumes

    Science.gov (United States)

    Pidlisecky, Adam; Singha, K.; Day-Lewis, F. D.

    2011-01-01

    Difference geophysical tomography (e.g. radar, resistivity and seismic) is used increasingly for imaging fluid flow and mass transport associated with natural and engineered hydrologic phenomena, including tracer experiments, in situ remediation and aquifer storage and recovery. Tomographic data are collected over time, inverted and differenced against a background image to produce 'snapshots' revealing changes to the system; these snapshots readily provide qualitative information on the location and morphology of plumes of injected tracer, remedial amendment or stored water. In principle, geometric moments (i.e. total mass, centres of mass, spread, etc.) calculated from difference tomograms can provide further quantitative insight into the rates of advection, dispersion and mass transfer; however, recent work has shown that moments calculated from tomograms are commonly biased, as they are strongly affected by the subjective choice of regularization criteria. Conventional approaches to regularization (Tikhonov) and parametrization (image pixels) result in tomograms which are subject to artefacts such as smearing or pixel estimates taking on the sign opposite to that expected for the plume under study. Here, we demonstrate a novel parametrization for imaging plumes associated with hydrologic phenomena. Capitalizing on the mathematical analogy between moment-based descriptors of plumes and the moment-based parameters of probability distributions, we design an inverse problem that (1) is overdetermined and computationally efficient because the image is described by only a few parameters, (2) produces tomograms consistent with expected plume behaviour (e.g. changes of one sign relative to the background image), (3) yields parameter estimates that are readily interpreted for plume morphology and offer direct insight into hydrologic processes and (4) requires comparatively few data to achieve reasonable model estimates. We demonstrate the approach in a series of

  7. Positron emission mammography with tomographic acquisition using dual planar detectors: initial evaluations

    International Nuclear Information System (INIS)

    Smith, Mark F; Raylman, Raymond R; Majewski, Stan; Weisenberger, Andrew G

    2004-01-01

    Positron emission mammography (PEM) with tomographic acquisition using dual planar detectors rotating about the breast can obtain complete angular sampling and has the potential to improve activity estimation compared with PEM using stationary detectors. PEM tomography (PEMT) was compared with stationary PEM for point source and compressed breast phantom studies performed with a compact dual detector system. The acquisition geometries were appropriate for the target application of PEM guidance of stereotactic core biopsy. Images were reconstructed with a three-dimensional iterative maximum likelihood expectation maximization algorithm. PEMT eliminated blurring normal to the detectors seen with stationary PEM. Depth of interaction effects distorted the shape of the point spread functions for PEMT as the angular range from normal incidence of lines of response used in image reconstruction increased. Streak artefacts in PEMT for large detector rotation increments led to the development of an expression for the maximum rotation increment that maintains complete angular sampling. Studies with a compressed breast phantom were used to investigate contrast and signal-to-noise ratio (SNR) trade-offs for different sized spherical tumour models. PEMT and PEM both had advantages depending on lesion size and detector separation. The most appropriate acquisition method for specific detection or quantitation tasks requires additional investigation

  8. Simulating multi-spacecraft Heliospheric Imager observations for tomographic reconstruction of interplanetary CMEs

    Science.gov (United States)

    Barnes, D.

    2017-12-01

    The multiple, spatially separated vantage points afforded by the STEREO and SOHO missions provide physicists with a means to infer the three-dimensional structure of the solar corona via tomographic imaging. The reconstruction process combines these multiple projections of the optically thin plasma to constrain its three-dimensional density structure and has been successfully applied to the low corona using the STEREO and SOHO coronagraphs. However, the technique is also possible at larger, inter-planetary distances using wide-angle imagers, such as the STEREO Heliospheric Imagers (HIs), to observe faint solar wind plasma and Coronal Mass Ejections (CMEs). Limited small-scale structure may be inferred from only three, or fewer, viewpoints and the work presented here is done so with the aim of establishing techniques for observing CMEs with upcoming and future HI-like technology. We use simulated solar wind densities to compute realistic white-light HI observations, with which we explore the requirements of such instruments for determining solar wind plasma density structure via tomography. We exploit this information to investigate the optimal orbital characteristics, such as spacecraft number, separation, inclination and eccentricity, necessary to perform the technique with HIs. Further to this we argue that tomography may be greatly enhanced by means of improved instrumentation; specifically, the use of wide-angle imagers capable of measuring polarised light. This work has obvious space weather applications, serving as a demonstration for potential future missions (such as at L1 and L5) and will prove timely in fully exploiting the science return from the upcoming Solar Orbiter and Parker Solar Probe missions.

  9. Photon emission tomographic apparatus and method

    International Nuclear Information System (INIS)

    Blum, A.S.

    1983-01-01

    Tomographic imaging system employs large area, collimated scintillation detector rotated around radiation emitting subject. Detector support rotates with an inner ring inside a stationary outer ring. Counterbalanced detector support arm is forced by spring action to cause collimator face to follow body contour as detector rotates around the body, thereby reducing collimator to subject distance to improve system resolution. Includes adjustable subject support system

  10. Development of a 30-week-pregnant female tomographic model from computed tomography (CT) images for Monte Carlo organ dose calculations

    International Nuclear Information System (INIS)

    Shi Chengyu; Xu, X. George

    2004-01-01

    Assessment of radiation dose and risk to a pregnant woman and her fetus is an important task in radiation protection. Although tomographic models for male and female patients of different ages have been developed using medical images, such models for pregnant women had not been developed to date. This paper reports the construction of a partial-body model of a pregnant woman from a set of computed tomography (CT) images. The patient was 30 weeks into pregnancy, and the CT scan covered the portion of the body from above liver to below pubic symphysis in 70 slices. The thickness for each slice is 7 mm, and the image resolution is 512x512 pixels in a 48 cmx48 cm field; thus, the voxel size is 6.15 mm 3 . The images were segmented to identify 34 major internal organs and tissues considered sensitive to radiation. Even though the masses are noticeably different from other models, the three-dimensional visualization verified the segmentation and its suitability for Monte Carlo calculations. The model has been implemented into a Monte Carlo code, EGS4-VLSI (very large segmented images), for the calculations of radiation dose to a pregnant woman. The specific absorbed fraction (SAF) results for internal photons were compared with those from a stylized model. Small and large differences were found, and the differences can be explained by mass differences and by the relative geometry differences between the source and the target organs. The research provides the radiation dosimetry community with the first voxelized tomographic model of a pregnant woman, opening the door to future dosimetry studies

  11. Computed-tomographic determination of mineral content of bones

    International Nuclear Information System (INIS)

    Delov, I.; Tabakov, S.

    1988-01-01

    The problem of precise computed-tomographic densitometry of the mineral content of bones is pointed out. A method is proposed including the use of standard density and observance of definite radiation, scanning and image estimation parameters. A good correlation of the results obtained for the mineral content of the lumbar vertebrae with literature data are reported. A method is also described for determining the mineral content of tubular bones based on densiprofile check-up of the computed-tomographic density. The procedure takes 10-15 minutes and includes 1 or 2 scans. It might therefore gain wide acceptance for the diagnosis and tracing of osteoporosis and other osteopathies associated with distrorted calcium metabolism

  12. Percutaneous Thermal Ablation with Ultrasound Guidance. Fusion Imaging Guidance to Improve Conspicuity of Liver Metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Hakime, Antoine, E-mail: thakime@yahoo.com; Yevich, Steven; Tselikas, Lambros; Deschamps, Frederic [Gustave Roussy - Cancer Campus, Interventional Radiology Department (France); Petrover, David [Imagerie Médicale Paris Centre, IMPC (France); Baere, Thierry De [Gustave Roussy - Cancer Campus, Interventional Radiology Department (France)

    2017-05-15

    PurposeTo assess whether fusion imaging-guided percutaneous microwave ablation (MWA) can improve visibility and targeting of liver metastasis that were deemed inconspicuous on ultrasound (US).Materials and MethodsMWA of liver metastasis not judged conspicuous enough on US was performed under CT/US fusion imaging guidance. The conspicuity before and after the fusion imaging was graded on a five-point scale, and significance was assessed by Wilcoxon test. Technical success, procedure time, and procedure-related complications were evaluated.ResultsA total of 35 patients with 40 liver metastases (mean size 1.3 ± 0.4 cm) were enrolled. Image fusion improved conspicuity sufficiently to allow fusion-targeted MWA in 33 patients. The time required for image fusion processing and tumors’ identification averaged 10 ± 2.1 min (range 5–14). Initial conspicuity on US by inclusion criteria was 1.2 ± 0.4 (range 0–2), while conspicuity after localization on fusion imaging was 3.5 ± 1 (range 1–5, p < 0.001). Technical success rate was 83% (33/40) in intention-to-treat analysis and 100% in analysis of treated tumors. There were no major procedure-related complications.ConclusionsFusion imaging broadens the scope of US-guided MWA to metastasis lacking adequate conspicuity on conventional US. Fusion imaging is an effective tool to increase the conspicuity of liver metastases that were initially deemed non visualizable on conventional US imaging.

  13. Tomographic findings of lobar consolidation in primary pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Pereira, Bruno Alberto Falcao; Macedo, Solange Goncalves David de; Penna, Claudia Renata Rezende

    2009-01-01

    Objective: To describe tomographic findings of lobar consolidation as early manifestation of primary pulmonary tuberculosis. Materials and methods: The present study was developed at Hospital Municipal Jesus, Rio de Janeiro, RJ, Brazil, in the period between 2002 and 2006, retrospectively evaluating tomographic findings in four children aged from 3 to 14 months with lobar consolidation as an early manifestation of primary pulmonary tuberculosis. Results: The most frequently found radiological pattern was lobar consolidation with calcifications, cavitation and intermingle necrotic areas, associated with bulging fissure. Signs of bronchogenic dissemination and lymph node enlargement were observed in all of the four children. Consolidation with a pseudotumor aspect and masslike effect was observed in one case. Conclusion: The cases included in the present study have demonstrated that primary pulmonary tuberculosis manifested as lobar consolidation presents typical tomographic images such as cavitation, hypodense areas and calcifications intermingled with consolidation. The association with lymph node enlargement with central necrosis and signs of bronchogenic dissemination reinforce the diagnosis of tuberculosis. (author)

  14. Investigating Gravity Waves in Polar Mesospheric Clouds Using Tomographic Reconstructions of AIM Satellite Imagery

    Science.gov (United States)

    Hart, V. P.; Taylor, M. J.; Doyle, T. E.; Zhao, Y.; Pautet, P.-D.; Carruth, B. L.; Rusch, D. W.; Russell, J. M.

    2018-01-01

    This research presents the first application of tomographic techniques for investigating gravity wave structures in polar mesospheric clouds (PMCs) imaged by the Cloud Imaging and Particle Size instrument on the NASA AIM satellite. Albedo data comprising consecutive PMC scenes were used to tomographically reconstruct a 3-D layer using the Partially Constrained Algebraic Reconstruction Technique algorithm and a previously developed "fanning" technique. For this pilot study, a large region (760 × 148 km) of the PMC layer (altitude 83 km) was sampled with a 2 km horizontal resolution, and an intensity weighted centroid technique was developed to create novel 2-D surface maps, characterizing the individual gravity waves as well as their altitude variability. Spectral analysis of seven selected wave events observed during the Northern Hemisphere 2007 PMC season exhibited dominant horizontal wavelengths of 60-90 km, consistent with previous studies. These tomographic analyses have enabled a broad range of new investigations. For example, a clear spatial anticorrelation was observed between the PMC albedo and wave-induced altitude changes, with higher-albedo structures aligning well with wave troughs, while low-intensity regions aligned with wave crests. This result appears to be consistent with current theories of PMC development in the mesopause region. This new tomographic imaging technique also provides valuable wave amplitude information enabling further mesospheric gravity wave investigations, including quantitative analysis of their hemispheric and interannual characteristics and variations.

  15. Direct aperture deformation: An interfraction image guidance strategy

    International Nuclear Information System (INIS)

    Feng Yuanming; Castro-Pareja, Carlos; Shekhar, Raj; Yu, Cedric

    2006-01-01

    A new scheme, called direct aperture deformation (DAD), for online correction of interfraction geometric uncertainties under volumetric imaging guidance is presented. Using deformable image registration, the three-dimensional geometric transformation matrix can be derived that associates the planning image set and the images acquired on the day of treatment. Rather than replanning or moving the patient, we use the deformation matrix to morph the treatment apertures as a potential online correction method. A proof-of-principle study using an intensity-modulated radiation therapy plan for a prostate cancer patient was conducted. The method, procedure, and algorithm of DAD are described. The dose-volume histograms from the original plan, reoptimized plan, and rigid-body translation plan are compared with the ones from the DAD plan. The study showed the feasibility of the DAD as a general method for both target dislocation and deformation. As compared with using couch translation to move the patient, DAD is capable of correcting both target dislocation and deformations. As compared with reoptimization, online correction using the DAD scheme could be completed within a few minutes rather than tens of minutes and the speed gain would be at a very small cost of plan quality

  16. Assessment of myocardial viability by dynamic tomographic iodine 123 iodophenylpentadecanoic acid imaging: comparison with rest-redistribution thallium 201 imaging.

    Science.gov (United States)

    Iskandrian, A S; Powers, J; Cave, V; Wasserleben, V; Cassell, D; Heo, J

    1995-01-01

    This study examined the ability of dynamic 123I-labeled iodophenylpentadecanoic acid (IPPA) imaging to detect myocardial viability in patients with left ventricular (LV) dysfunction caused by coronary artery disease. Serial 180-degree single-photon emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi 123I at rest in 21 patients with LV dysfunction (ejection fraction [EF] 34% +/- 11%). The segmental uptake was compared with that of rest-redistribution 201Tl images (20 segments/study). The number of perfusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there were more reversible IPPA defects than reversible thallium defects (7 +/- 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33% +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA defects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segments/patient; p = 0.075). 123I-labeled IPPA SPECT imaging is a promising new technique for assessment of viability. Reversible defects predict recovery of LV dysfunction after coronary revascularization.

  17. The inverse problems of reconstruction in the X-rays, gamma or positron tomographic imaging systems

    International Nuclear Information System (INIS)

    Grangeat, P.

    1999-01-01

    The revolution in imagery, brought by the tomographic technic in the years 70, allows the computation of local values cartography for the attenuation or the emission activity. The reconstruction techniques thus allow the connection from integral measurements to characteristic information distribution by inversion of the measurement equations. They are a main application of the solution technic for inverse problems. In a first part the author recalls the physical principles for measures in X-rays, gamma and positron imaging. Then he presents the various problems with their associated inversion techniques. The third part is devoted to the activity sector and examples, to conclude in the last part with the forecast. (A.L.B.)

  18. Same day injections of Tc-99m methoxy isobutyl isonitrile (hexamibi) for myocardial tomographic imaging: Comparison between rest-stress and stress-rest injection sequences

    International Nuclear Information System (INIS)

    Taillefer, R.; Gagnon, A.; Laflamme, L.; Leveille, J.; Phaneuf, D.C.

    1989-01-01

    It has been shown that both rest and stress 99m Tc-hexamibi myocardial perfusion imaging can be performed on the same day using two different doses injected within few h (the first one at rest followed by a second at stress). In order to evaluate and compare 2 sequences (rest-stress and stress-rest) of 99m Tc-hexamibi injections performed the same day, 18 patients with either abnormal 201 Tl myocardial scan or abnormal coronary angiography were studied with 2 99m Tc-hexamibi injections protocols. The rest-stress study was performed as follows: 7 mCi 99m Tc-hexamibi was injected at rest. Single photon emission computed tomography (SPECT) was performed 60 min later. Immediately after the rest study, patients were injected at peak stress with 25 mCi 99m Tc-hexamibi. Tomographic imaging was repeated 1 h later. Patients were submitted to the stress-rest protocol within 3 days. Tomographic imaging was done 1 h after a 7 mCi injection at stress. This study was followed by an injection of 25 mCi 99m Tc-hexamibi at rest, a tomographic study was performed 60 min later. Myocardial sections were reconstructed in horizontal long, vertical long, and short axes. Data analysis also included polar map representation. A total of 324 segments were interpreted blind by 3 observers, there was an agreement in 283/324 (87.3%) segments between the 2 protocols. However, 24 segments (7.4%) judged ischemic on rest-stress were called scars on stress-rest. In three patients, myocardial segments were judged normal on the rest image of the rest-stress protocol while they were found abnormal (false positive images) on the stress-rest sequence. Stress images from both protocols were judged similar in 17 patients. In conclusion, when using a short time interval (less than 2 h) between two 99m Tc-hexamibi injections, it is preferable to do a rest-stress sequence since the rest image performed initially represents a true rest study, which is not necessarily the case with the stress-rest sequence

  19. Fractal analysis of en face tomographic images obtained with full field optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wanrong; Zhu, Yue [Department of Optical Engineering, Nanjing University of Science and Technology, Jiangsu (China)

    2017-03-15

    The quantitative modeling of the imaging signal of pathological areas and healthy areas is necessary to improve the specificity of diagnosis with tomographic en face images obtained with full field optical coherence tomography (FFOCT). In this work, we propose to use the depth-resolved change in the fractal parameter as a quantitative specific biomarker of the stages of disease. The idea is based on the fact that tissue is a random medium and only statistical parameters that characterize tissue structure are appropriate. We successfully relate the imaging signal in FFOCT to the tissue structure in terms of the scattering function and the coherent transfer function of the system. The formula is then used to analyze the ratio of the Fourier transforms of the cancerous tissue to the normal tissue. We found that when the tissue changes from the normal to cancerous the ratio of the spectrum of the index inhomogeneities takes the form of an inverse power law and the changes in the fractal parameter can be determined by estimating slopes of the spectra of the ratio plotted on a log-log scale. The fresh normal and cancer liver tissues were imaged to demonstrate the potential diagnostic value of the method at early stages when there are no significant changes in tissue microstructures. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. The impact of reorienting cone-beam computed tomographic images in varied head positions on the coordinates of anatomical landmarks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hun; Jeong, Ho Gul; Hwang, Jae Joon; Lee, Jung Hee; Han, Sang Sun [Dept. of Oral and Maxillofacial Radiology, Yonsei University, College of Dentistry, Seoul (Korea, Republic of)

    2016-06-15

    The aim of this study was to compare the coordinates of anatomical landmarks on cone-beam computed tomographic (CBCT) images in varied head positions before and after reorientation using image analysis software. CBCT images were taken in a normal position and four varied head positions using a dry skull marked with 3 points where gutta percha was fixed. In each of the five radiographic images, reference points were set, 20 anatomical landmarks were identified, and each set of coordinates was calculated. Coordinates in the images from the normally positioned head were compared with those in the images obtained from varied head positions using statistical methods. Post-reorientation coordinates calculated using a three-dimensional image analysis program were also compared to the reference coordinates. In the original images, statistically significant differences were found between coordinates in the normal-position and varied-position images. However, post-reorientation, no statistically significant differences were found between coordinates in the normal-position and varied-position images. The changes in head position impacted the coordinates of the anatomical landmarks in three-dimensional images. However, reorientation using image analysis software allowed accurate superimposition onto the reference positions.

  1. Mobile 3D tomograph

    International Nuclear Information System (INIS)

    Illerhaus, Bernhard; Goebbels, Juergen; Onel, Yener; Sauerwein, Christoph

    2008-01-01

    Mobile tomographs often have the problem that high spatial resolution is impossible owing to the position or setup of the tomograph. While the tree tomograph developed by Messrs. Isotopenforschung Dr. Sauerwein GmbH worked well in practice, it is no longer used as the spatial resolution and measuring time are insufficient for many modern applications. The paper shows that the mechanical base of the method is sufficient for 3D CT measurements with modern detectors and X-ray tubes. CT measurements with very good statistics take less than 10 min. This means that mobile systems can be used, e.g. in examinations of non-transportable cultural objects or monuments. Enhancement of the spatial resolution of mobile tomographs capable of measuring in any position is made difficult by the fact that the tomograph has moving parts and will therefore have weight shifts. With the aid of tomographies whose spatial resolution is far higher than the mechanical accuracy, a correction method is presented for direct integration of the Feldkamp algorithm [de

  2. TomoBank: a tomographic data repository for computational x-ray science

    Science.gov (United States)

    De Carlo, Francesco; Gürsoy, Doğa; Ching, Daniel J.; Joost Batenburg, K.; Ludwig, Wolfgang; Mancini, Lucia; Marone, Federica; Mokso, Rajmund; Pelt, Daniël M.; Sijbers, Jan; Rivers, Mark

    2018-03-01

    There is a widening gap between the fast advancement of computational methods for tomographic reconstruction and their successful implementation in production software at various synchrotron facilities. This is due in part to the lack of readily available instrument datasets and phantoms representative of real materials for validation and comparison of new numerical methods. Recent advancements in detector technology have made sub-second and multi-energy tomographic data collection possible (Gibbs et al 2015 Sci. Rep. 5 11824), but have also increased the demand to develop new reconstruction methods able to handle in situ (Pelt and Batenburg 2013 IEEE Trans. Image Process. 22 5238-51) and dynamic systems (Mohan et al 2015 IEEE Trans. Comput. Imaging 1 96-111) that can be quickly incorporated in beamline production software (Gürsoy et al 2014 J. Synchrotron Radiat. 21 1188-93). The x-ray tomography data bank, tomoBank, provides a repository of experimental and simulated datasets with the aim to foster collaboration among computational scientists, beamline scientists, and experimentalists and to accelerate the development and implementation of tomographic reconstruction methods for synchrotron facility production software by providing easy access to challenging datasets and their descriptors.

  3. Virtual and augmented medical imaging environments: enabling technology for minimally invasive cardiac interventional guidance.

    Science.gov (United States)

    Linte, Cristian A; White, James; Eagleson, Roy; Guiraudon, Gérard M; Peters, Terry M

    2010-01-01

    Virtual and augmented reality environments have been adopted in medicine as a means to enhance the clinician's view of the anatomy and facilitate the performance of minimally invasive procedures. Their value is truly appreciated during interventions where the surgeon cannot directly visualize the targets to be treated, such as during cardiac procedures performed on the beating heart. These environments must accurately represent the real surgical field and require seamless integration of pre- and intra-operative imaging, surgical tracking, and visualization technology in a common framework centered around the patient. This review begins with an overview of minimally invasive cardiac interventions, describes the architecture of a typical surgical guidance platform including imaging, tracking, registration and visualization, highlights both clinical and engineering accuracy limitations in cardiac image guidance, and discusses the translation of the work from the laboratory into the operating room together with typically encountered challenges.

  4. Evaluation of quality of tomographs of Rio de Janeiro state, Brazil

    International Nuclear Information System (INIS)

    Travassos, P.C.B.; Belem, V.R.; Magalhaes, L.A.; Almeida, C.E.A. de

    2014-01-01

    Computerized tomographs used in 56 institutions in the state of Rio de Janeiro were evaluated. Criteria of image quality and dosimetry were submitted. The results showed that some not performed optimize their protocols examinations or perform wrongly, which results in an increase in the dose received by patients, and an image in compromised quality. (author)

  5. Mesooptical microscope as a tomographical device

    International Nuclear Information System (INIS)

    Soroko, L.M.

    1989-01-01

    It is shown that there are at least four regions which are common for the mesooptical microscopes, on the one hand, and for the reconstructed tomography, on the other hand. The following characteristics of the mesooptical microscope show the tomographical properties: the structure of the output data concerning the orientation and the position in space of the straight-line objects going at small angles with the perpendicular to the given tomographic plane, the behaviour of the two-dimensional fourier-transform of the straight-line object in the course of the rotation of this object with respect to the specified axis in space, the scanning algorithm of the nuclear emulsion volume by the fence-like illuminated region in the mesooptical microscope for searching for particle tracks going parallel to the optical axis of the microscope, and, finally, the fact that the mesooptical images of the straight-line particle tracks with a common vertex in the nuclear emulsion lie on the sinogram. 12 refs.; 16 figs

  6. Computed tomographic, magnetic resonance imaging, and cross-sectional anatomic features of the manus in a normal American black bear (Ursus americanus).

    Science.gov (United States)

    Ober, C P; Freeman, L E

    2010-06-01

    The purpose of this study was to provide a detailed description of cross-sectional anatomic structures of the manus of a black bear cadaver and correlate anatomic findings with corresponding features in computed tomographic (CT) and magnetic resonance (MR) images. CT, MR imaging, and transverse sectioning were performed on the thoracic limb of a cadaver female black bear which had no evidence of lameness or thoracic limb abnormality prior to death. Features in CT and MR images corresponding to clinically important anatomic structures in anatomic sections were identified. Most of the structures identified in transverse anatomic sections were also identified using CT and MR imaging. Bones, muscles and tendons were generally easily identified with both imaging modalities, although divisions between adjacent muscles were rarely visible with CT and only visible sometimes with MR imaging. Vascular structures could not be identified with either imaging modality.

  7. Effects of small variations of speed of sound in optoacoustic tomographic imaging

    International Nuclear Information System (INIS)

    Deán-Ben, X. Luís; Ntziachristos, Vasilis; Razansky, Daniel

    2014-01-01

    Purpose: Speed of sound difference in the imaged object and surrounding coupling medium may reduce the resolution and overall quality of optoacoustic tomographic reconstructions obtained by assuming a uniform acoustic medium. In this work, the authors investigate the effects of acoustic heterogeneities and discuss potential benefits of accounting for those during the reconstruction procedure. Methods: The time shift of optoacoustic signals in an acoustically heterogeneous medium is studied theoretically by comparing different continuous and discrete wave propagation models. A modification of filtered back-projection reconstruction is subsequently implemented by considering a straight acoustic rays model for ultrasound propagation. The results obtained with this reconstruction procedure are compared numerically and experimentally to those obtained assuming a heuristically fitted uniform speed of sound in both full-view and limited-view optoacoustic tomography scenarios. Results: The theoretical analysis showcases that the errors in the time-of-flight of the signals predicted by considering the straight acoustic rays model tend to be generally small. When using this model for reconstructing simulated data, the resulting images accurately represent the theoretical ones. On the other hand, significant deviations in the location of the absorbing structures are found when using a uniform speed of sound assumption. The experimental results obtained with tissue-mimicking phantoms and a mouse postmortem are found to be consistent with the numerical simulations. Conclusions: Accurate analysis of effects of small speed of sound variations demonstrates that accounting for differences in the speed of sound allows improving optoacoustic reconstruction results in realistic imaging scenarios involving acoustic heterogeneities in tissues and surrounding media

  8. Initial results from the Donner 600-crystal positron tomograph

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Huesman, R.H.; Cahoon, J.L.; Geyer, A.B.; Uber, D.C.; Vuletich, T.; Budinger, T.F.

    1987-01-01

    These results show the 3-mm BGO crystals can improve the resolution in positron tomography by a substantial factor. This measured crystal-pair resolution of 2.4 mm FWHM and the reconstructed image resolution of 2.9 mm FWHM at the center of the tomograph are in good agreement with expected values. The most serious limitation of the detector design is that only a single section can be imaged. 4 refs., 4 figs

  9. Accuracy of daily image guidance for hypofractionated liver radiotherapy with active breathing control

    International Nuclear Information System (INIS)

    Dawson, Laura A.; Eccles, Cynthia; Bissonnette, Jean-Pierre; Brock, Kristy K.

    2005-01-01

    Purpose: A six-fraction, high-precision radiotherapy protocol for unresectable liver cancer has been developed in which active breathing control (ABC) is used to immobilize the liver and daily megavoltage (MV) imaging and repositioning is used to decrease geometric uncertainties. We report the accuracy of setup in the first 20 patients consecutively treated using this approach. Methods and materials: After setup using conventional skin marks and lasers, orthogonal MV images were acquired with the liver immobilized using ABC. The images were aligned to reference digitally reconstructed radiographs using the diaphragm for craniocaudal (CC) alignment and the vertebral bodies for anterior-posterior (AP) and mediolateral (ML) alignment. Adjustments were made for positioning errors >3 mm. Verification imaging was repeated after repositioning to assess for residual positioning error. Offline image matching was conducted to determine the setup accuracy using this approach compared with the initial setup error before repositioning. Real-time beam's-eye-view MV movies containing an air-diaphragm interface were also evaluated. Results: A total of 405 images were evaluated from 20 patients. Repositioning occurred in 109 of 120 fractions because of offsets >3 mm. Three to eight beam angles, with up to four segments per field, were used for each isocenter. Breath holds of up to 27 s were used for imaging and treatment. The average time from the initial verification image to the last treatment beam was 21 min. Image guidance and repositioning reduced the population random setup errors (σ) from 6.5 mm (CC), 4.2 mm (ML), and 4.7 mm (AP) to 2.5 mm (CC), 2.8 mm (ML), and 2.9 mm (AP). The average individual random setup errors (σ) were reduced from 4.5 mm (CC), 3.2 mm (AP), and 2.5 mm (ML) to 2.2 mm (CC), 2.0 mm (AP), and 2.0 mm (ML). The standard deviation of the distribution of systematic deviations (Σ) was also reduced from 5.1 mm (CC), 3.4 mm (ML), and 3.1 mm (AP) to 1.4 mm (CC

  10. Quantitative analysis of length-diameter distribution and cross-sectional properties of fibers from three-dimensional tomographic images

    DEFF Research Database (Denmark)

    Miettinen, Arttu; Joffe, Roberts; Madsen, Bo

    2013-01-01

    obtained from optical microscopy of polished cross-sections of a composite. This approach gives accurate yet local results, but a rather large number of optical images have to be processed to achieve a representative description of the morphology of the material. In this work a fully automatic algorithm......A number of rule-of-mixture micromechanical models have been successfully used to predict the mechanical properties of short fiber composites. However, in order to obtain accurate predictions, a detailed description of the internal structure of the material is required. This information is often...... for estimating the length-diameter distribution of solid or hollow fibers, utilizing three-dimensional X-ray tomographic images, is presented. The method is based on a granulometric approach for fiber length distribution measurement, combined with a novel algorithm that relates cross-sectional fiber properties...

  11. William, a voxel model of child anatomy from tomographic images for Monte Carlo dosimetry calculations

    International Nuclear Information System (INIS)

    Caon, M.

    2010-01-01

    Full text: Medical imaging provides two-dimensional pictures of the human internal anatomy from which may be constructed a three-dimensional model of organs and tissues suitable for calculation of dose from radiation. Diagnostic CT provides the greatest exposure to radiation per examination and the frequency of CT examination is high. Esti mates of dose from diagnostic radiography are still determined from data derived from geometric models (rather than anatomical models), models scaled from adult bodies (rather than bodies of children) and CT scanner hardware that is no longer used. The aim of anatomical modelling is to produce a mathematical representation of internal anatomy that has organs of realistic size, shape and positioning. The organs and tissues are represented by a great many cuboidal volumes (voxels). The conversion of medical images to voxels is called segmentation and on completion every pixel in an image is assigned to a tissue or organ. Segmentation is time consuming. An image processing pack age is used to identify organ boundaries in each image. Thirty to forty tomographic voxel models of anatomy have been reported in the literature. Each model is of an individual, or a composite from several individuals. Images of children are particularly scarce. So there remains a need for more paediatric anatomical models. I am working on segmenting ''William'' who is 368 PET-CT images from head to toe of a seven year old boy. William will be used for Monte Carlo dose calculations of dose from CT examination using a simulated modern CT scanner.

  12. New Pn and Sn tomographic images of the uppermost mantle beneath the Mediterranean region

    Science.gov (United States)

    Gil, A.; Díaz, J.; Gallart, J.

    2012-04-01

    We present here new images of the seismic velocity and anisotropy variations in the uppermost mantle beneath the Mediterranean region, compiled from inversion of Pn and Sn phases. The method of Hearn (1996) has been applied to Pn and Sn lectures from the catalogs of the International Seismological Center and the Spanish Instituto Geografico Nacional. A total of 1,172,293 Pn arrivals coming from 16,527 earthquakes recorded at 1,657 stations with epicentral distances between 220 km and 1400 km have been retained (331,567 arrivals from 15,487events at 961 stations for Sn). Our results, grossly consistent with available 3D tomography images, show significant features well correlated with surface geology. The Pn velocities are high (>8.2 km/s) beneath major sedimentary basins (western Alboran Sea, Valencia Trough, Adriatic Sea, Aquitaine, Guadalquivir, Rharb, Aquitaine and Po basins), and low (Islands, probably related to a thermal anomaly associated to the westward displacement of the Alboran block along the Emile Baudot escarpment 16 Ma ago. The Pn anisotropic image shows consistent orientations sub-parallel to major orogenic structures, such as Betics, Apennines, Calabrian Arc and Alps. The station delays beneath Betic and Rif ranges are strongly negative, suggesting the presence of crustal thickening all along the Gibraltar Arc. However, only the Betics have a very strong low-velocity anomaly and a pronounced anisotropy pattern. The Sn tomographic image correlates well with the Pn image, even if some relevant differences can be observed beneath particular regions.

  13. Methodology for tomographic imaging ahead of mining using the shearer as a seismic source

    Energy Technology Data Exchange (ETDEWEB)

    King, A.; Luo, X. [CSIRO Exploration and Mining, Kenmore, Qld. (Australia)

    2009-03-15

    Poor rock conditions in a coal long wall panel can result in roof collapse when a problematic zone is mined, significantly interrupting mine production. The ability to image rock conditions (stress and degree of fracturing) ahead of the face gives the miners the ability to respond proactively to such problems. This method uses the energy from mining machinery, in this case a coal shearer, to produce an image of the rock velocity ahead of the mining face without interrupting mining. Data from an experiment illustrates the concept. Geophones installed in gate-road roofs record the noise generated by the shearer after it has traversed the panel ahead of the mining face. A generalized crosscorrelation of the signals from pairs of sensors determines relative arrival times from the continuous seismic noise produced by the shearer. These relative times can then be inverted for a velocity structure. The crosscorrelations, performed in the frequency domain, are weighted by a confidence value derived from the spectral coherence between the traces. This produces stable crosscorrelation lags in the presence of noise. The errors in the time-domain data are propagated through to the relative traveltimes and then to the final tomographic velocity image, yielding an estimate of the uncertainty in velocity at each point. This velocity image can then be used to infer information about the stress and fracture state of the rock, providing advance warning of potentially hazardous zones.

  14. Dental computed tomographic imaging as age estimation: morphological analysis of the third molar of a group of Turkish population.

    Science.gov (United States)

    Cantekin, Kenan; Sekerci, Ahmet Ercan; Buyuk, Suleyman Kutalmis

    2013-12-01

    Computed tomography (CT) is capable of providing accurate and measurable 3-dimensional images of the third molar. The aims of this study were to analyze the development of the mandibular third molar and its relation to chronological age and to create new reference data for a group of Turkish participants aged 9 to 25 years on the basis of cone-beam CT images. All data were obtained from the patients' records including medical, social, and dental anamnesis and cone-beam CT images of 752 patients. Linear regression analysis was performed to obtain regression formulas for dental age calculation with chronological age and to determine the coefficient of determination (r) for each sex. Statistical analysis showed a strong correlation between age and third-molar development for the males (r2 = 0.80) and the females (r2 = 0.78). Computed tomographic images are clinically useful for accurate and reliable estimation of dental ages of children and youth.

  15. An evolutionary algorithm for tomographic reconstructions in limited data sets problems

    International Nuclear Information System (INIS)

    Turcanu, Catrinel; Craciunescu, Teddy

    2000-01-01

    The paper proposes a new method for tomographic reconstructions. Unlike nuclear medicine applications, in physical science problems we are often confronted with limited data sets: constraints in the number of projections or limited angle views. The problem of image reconstruction from projections may be considered as a problem of finding an image (solution) having projections that match the experimental ones. In our approach, we choose a statistical correlation coefficient to evaluate the fitness of any potential solution. The optimization process is carried out by an evolutionary algorithm. Our algorithm has some problem-oriented characteristics. One of them is that a chromosome, representing a potential solution, is not linear but coded as a matrix of pixels corresponding to a two-dimensional image. This kind of internal representation reflects the genuine manifestation and slight differences between two points situated in the original problem space give rise to similar differences once they become coded. Another particular feature is a newly built crossover operator: the grid-based crossover, suitable for high dimension two-dimensional chromosomes. Except for the population size and the dimension of the cutting grid for the grid-based crossover, all the other parameters of the algorithm are independent of the geometry of the tomographic reconstruction. The performances of the method are evaluated in comparison with a traditional tomographic method, based on the maximization of the entropy of the image, that proved to work well with limited data sets. The test phantom is typical for an application with limited data sets: the determination of the neutron energy spectra with time resolution in case of short-pulsed neutron emission. The qualitative judgement and also the quantitative one, based on some figures of merit, point out that the proposed method ensures an improved reconstruction of shapes, sizes and resolution in the image, even in the presence of noise

  16. Evaluation of tomographic image quality of extended and conventional parallel hole collimators using maximum likelihood expectation maximization algorithm by Monte Carlo simulations.

    Science.gov (United States)

    Moslemi, Vahid; Ashoor, Mansour

    2017-10-01

    One of the major problems associated with parallel hole collimators (PCs) is the trade-off between their resolution and sensitivity. To solve this problem, a novel PC - namely, extended parallel hole collimator (EPC) - was proposed, in which particular trapezoidal denticles were increased upon septa on the side of the detector. In this study, an EPC was designed and its performance was compared with that of two PCs, PC35 and PC41, with a hole size of 1.5 mm and hole lengths of 35 and 41 mm, respectively. The Monte Carlo method was used to calculate the important parameters such as resolution, sensitivity, scattering, and penetration ratio. A Jaszczak phantom was also simulated to evaluate the resolution and contrast of tomographic images, which were produced by the EPC6, PC35, and PC41 using the Monte Carlo N-particle version 5 code, and tomographic images were reconstructed by using maximum likelihood expectation maximization algorithm. Sensitivity of the EPC6 was increased by 20.3% in comparison with that of the PC41 at the identical spatial resolution and full-width at tenth of maximum here. Moreover, the penetration and scattering ratio of the EPC6 was 1.2% less than that of the PC41. The simulated phantom images show that the EPC6 increases contrast-resolution and contrast-to-noise ratio compared with those of PC41 and PC35. When compared with PC41 and PC35, EPC6 improved trade-off between resolution and sensitivity, reduced penetrating and scattering ratios, and produced images with higher quality. EPC6 can be used to increase detectability of more details in nuclear medicine images.

  17. Comparison of primary thyroid lymphoma with anaplastic thyroid carcinoma on computed tomographic imaging

    International Nuclear Information System (INIS)

    Ishikawa, Hitoshi; Mitsuhashi, Norio; Niibe, Hideo

    2002-01-01

    Primary non-Hodgkin's lymphoma (LY) and anaplastic carcinoma (AC) of the thyroid gland are rare malignant tumors, and the initial symptoms of these diseases are very similar. The aim of our study was to compare the characteristics of the two diseases using computed tomographic (CT) scans in order to make an accurate differential diagnosis. Ten patients with LY and 10 with AC were analyzed. Differences in the CT findings of the two diseases were evaluated before treatment and statistically tested with either Student's t-test or the chi-square test. In the analysis of characteristics of CT imaging, the existence of calcification and necrosis, and heterogeneous tumor were dominant findings in AC, and there was a statistically significant difference in frequency between the two diseases (p<0.01). Calcification detected in AC was usually multiple and/or gross (mean size: φ8.2 mm). All lymphadenopathies were delineated as having the same homogeneous attenuation as the tumors in the thyroid gland in LY, but were shown as irregular rim enhancement in AC. The CT features of the two diseases are characteristic in terms of calcification, necrosis, and tumor composition. Evaluation by means of CT imaging is useful in distinguishing between LY and AC. (author)

  18. X-ray tomographic apparatus

    International Nuclear Information System (INIS)

    Walters, R.G.

    1982-01-01

    An x-ray tomographic system consists of a radiation source such as gamma or x radiation which produces a fan-shaped beam. The fan is wide enough to encompass the patient circle. The system further includes means for rotating the radiation source about the patient for less than a full rotation, and detectors for detecting the radiation at positions that surround the patient by 180 0 plus the angle of the fan beam plus the angle between adjacent fan detectors. Attenuation data from the detectors is sorted into detector fans of attenuation data, then processed. The convolved data is back-projected into an image memory and displayed on a video monitor

  19. Experimental device, corresponding forward model and processing of the experimental data using wavelet analysis for tomographic image reconstruction applied to eddy current nondestructive evaluation

    International Nuclear Information System (INIS)

    Joubert, P.Y.; Madaoui, N.

    1999-01-01

    In the context of eddy current non destructive evaluation using a tomographic image reconstruction process, the success of the reconstruction depends not only on the choice of the forward model and of the inversion algorithms, but also on the ability to extract the pertinent data from the raw signal provided by the sensor. We present in this paper, an experimental device designed for imaging purposes, the corresponding forward model, and a pre-processing of the experimental data using wavelet analysis. These three steps implemented with an inversion algorithm, will allow in the future to perform image reconstruction of 3-D flaws. (authors)

  20. Tomographic examination table

    International Nuclear Information System (INIS)

    Redington, R.W.; Henkes, J.L.

    1979-01-01

    Equipment is described for positioning and supporting patients during tomographic mammography using X-rays. The equipment consists of a table and fabric slings which permit the examination of a downward, pendant breast of a prone patient by allowing the breast to pass through a aperture in the table into a fluid filled container. The fluid has an X-ray absorption coefficient similar to that of soft human tissue allowing high density resolution radiography and permitting accurate detection of breast tumours. The shape of the equipment and the positioning of the patient allow the detector and X-ray source to rotate 360 0 about a vertical axis through the breast. This permits the use of relatively simple image reconstruction algorithms and a divergent X-ray geometry. (UK)

  1. Semi-automated software to measure luminal and stromal areas of choroid in optical coherence tomographic images.

    Science.gov (United States)

    Sonoda, Shozo; Sakamoto, Taiji; Kakiuchi, Naoko; Shiihara, Hideki; Sakoguchi, Tomonori; Tomita, Masatoshi; Yamashita, Takehiro; Uchino, Eisuke

    2018-03-01

    To determine the capabilities of "EyeGround" software in measuring the choroidal cross sectional areas in optical coherence tomographic (OCT) images. Cross sectional, prospective study. The cross-sectional area of the subfoveal choroid within a 1500 µm diameter circle centered on the fovea was measured both with and without using the EyeGround software in the OCT images. The differences between the evaluation times and the results of the measurements were compared. The inter-rater, intra-rater, inter-method agreements were determined. Fifty-one eyes of 51 healthy subjects were studied: 24 men and 27 women with an average age of 35.0 ± 8.8 years. The time for analyzing a single image was significantly shorter with the software at 3.2±1.1 min than without the software at 12.1±5.1 min (P software, the inter-rater correlation efficient was significantly high [0.997, 95% CI (0.995-0.999)], and the intra-rater correlation efficient was also significantly high [0.999, 95% CI (0.999-1.0)]. The EyeGround software can measure the choroidal area in the OCT cross sectional images with good reproducibility and in a significantly shorter times. It can be a valuable tool for analyzing the choroid.

  2. Reconstruction of tomographic images from projections of a small number of views by means of mathematical programming

    International Nuclear Information System (INIS)

    Kobayashi, Fujio; Yamaguchi, Shoichiro

    1985-01-01

    Fundamental studies have been made on the application of mathematical programming to the reconstruction of tomographic images from projections of a small number of views without requiring any circular symmetry nor periodicity. Linear programming and quadratic programming were applied to minimize the quadratic sum of the residue and to finally obtain optimized reconstruction images. The mathematical algorithms were verified by the method of computer simulation, and the relationship between the number of picture elements and the number of iterations necessary for convergence was also investigated. The methods of linear programming and quadratic programming require fairly simple mathematical procedures, and strict solutions can be obtained within a finite number of iterations. Their only draw back is the requirement of a large quantity of computer memory. But this problem will be desolved by the advent of large fast memory devices in the near future. (Aoki, K.)

  3. Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance.

    Science.gov (United States)

    Sveistrup, Joen; af Rosenschöld, Per Munck; Deasy, Joseph O; Oh, Jung Hun; Pommer, Tobias; Petersen, Peter Meidahl; Engelholm, Svend Aage

    2014-02-04

    Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1-2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5-7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction.

  4. MR imaging guidance and monitoring of focal thermotherapies. A review

    International Nuclear Information System (INIS)

    Mueller-Lisse, U.G.; California Univ., San Francisco, CA; Heuck, A.F.

    1998-01-01

    Minimally invasive thermotherapies for focal tissue destruction on the basis of laser-, microwave-, focused ultrasound-, or cryogeninduced changes of tissue temperature represent an alternative to surgical tissue ablation, particularly in the treatment of tumors. The thermotherapy modalities listed necessitate indirect guidance and monitoring, since they often do not lend themselves to immediate visual control. In the brain, in head and neck tumors, in the liver, and in the prostate, MRI reliably and accurately delineates both the positions of interstitial thermotherapy applicators and - in contrast-enhanced, T1-weighted images - the perfusion defects in tissue necrosis induced by thermotherapy. The transfer of results of in-vitro and in-vivo model studies to assess interstitial temperature and lesion development during thermotherapy to the actual treatment of patients, however, is still in an initial phase. Further development of both rapid MRI sequences and MRI scanners suited for interventions will show how far treatment systems and guidance systems can be adapted to one another. (orig.) [de

  5. Usefulness of automated biopsy guns in image-guided biopsy

    International Nuclear Information System (INIS)

    Lee, Jung Hyung; Rhee, Chang Soo; Lee, Sung Moon; Kim, Hong; Woo, Sung Ku; Suh, Soo Jhi

    1994-01-01

    To evaluate the usefulness of automated biopsy guns in image-guided biopsy of lung, liver, pancreas and other organs. Using automated biopsy devices, 160 biopsies of variable anatomic sites were performed: Biopsies were performed under ultrasonographic(US) guidance in 95 and computed tomographic (CT) guidance in 65. We retrospectively analyzed histologic results and complications. Specimens were adequate for histopathologic diagnosis in 143 of the 160 patients(89.4%)-Diagnostic tissue was obtained in 130 (81.3%), suggestive tissue obtained in 13(8.1%), and non-diagnostic tissue was obtained in 14(8.7%). Inadequate tissue was obtained in only 3(1.9%). There was no statistically significant difference between US-guided and CT-guided percutaneous biopsy. There was no occurrence of significant complication. We have experienced mild complications in only 5 patients-2 hematuria and 2 hematochezia in transrectal prostatic biopsy, and 1 minimal pneumothorax in CT-guided percutaneous lung biopsy. All of them were resolved spontaneously. The image-guided biopsy using the automated biopsy gun was a simple, safe and accurate method of obtaining adequate specimen for the histopathologic diagnosis

  6. Usefulness of automated biopsy guns in image-guided biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Hyung; Rhee, Chang Soo; Lee, Sung Moon; Kim, Hong; Woo, Sung Ku; Suh, Soo Jhi [School of Medicine, Keimyung University, Daegu (Korea, Republic of)

    1994-12-15

    To evaluate the usefulness of automated biopsy guns in image-guided biopsy of lung, liver, pancreas and other organs. Using automated biopsy devices, 160 biopsies of variable anatomic sites were performed: Biopsies were performed under ultrasonographic(US) guidance in 95 and computed tomographic (CT) guidance in 65. We retrospectively analyzed histologic results and complications. Specimens were adequate for histopathologic diagnosis in 143 of the 160 patients(89.4%)-Diagnostic tissue was obtained in 130 (81.3%), suggestive tissue obtained in 13(8.1%), and non-diagnostic tissue was obtained in 14(8.7%). Inadequate tissue was obtained in only 3(1.9%). There was no statistically significant difference between US-guided and CT-guided percutaneous biopsy. There was no occurrence of significant complication. We have experienced mild complications in only 5 patients-2 hematuria and 2 hematochezia in transrectal prostatic biopsy, and 1 minimal pneumothorax in CT-guided percutaneous lung biopsy. All of them were resolved spontaneously. The image-guided biopsy using the automated biopsy gun was a simple, safe and accurate method of obtaining adequate specimen for the histopathologic diagnosis.

  7. A high-throughput system for high-quality tomographic reconstruction of large datasets at Diamond Light Source.

    Science.gov (United States)

    Atwood, Robert C; Bodey, Andrew J; Price, Stephen W T; Basham, Mark; Drakopoulos, Michael

    2015-06-13

    Tomographic datasets collected at synchrotrons are becoming very large and complex, and, therefore, need to be managed efficiently. Raw images may have high pixel counts, and each pixel can be multidimensional and associated with additional data such as those derived from spectroscopy. In time-resolved studies, hundreds of tomographic datasets can be collected in sequence, yielding terabytes of data. Users of tomographic beamlines are drawn from various scientific disciplines, and many are keen to use tomographic reconstruction software that does not require a deep understanding of reconstruction principles. We have developed Savu, a reconstruction pipeline that enables users to rapidly reconstruct data to consistently create high-quality results. Savu is designed to work in an 'orthogonal' fashion, meaning that data can be converted between projection and sinogram space throughout the processing workflow as required. The Savu pipeline is modular and allows processing strategies to be optimized for users' purposes. In addition to the reconstruction algorithms themselves, it can include modules for identification of experimental problems, artefact correction, general image processing and data quality assessment. Savu is open source, open licensed and 'facility-independent': it can run on standard cluster infrastructure at any institution.

  8. Processing of acquisition data for a time of flight positron tomograph

    International Nuclear Information System (INIS)

    Robert, G.

    1987-10-01

    After a review of basic principles concerning the time of flight positron tomography, the LETI positron tomograph is briefly described. For performance optimization (acquisition, calibration, image reconstruction), various specialized operators have been designed: the realization of the acquisition system is presented [fr

  9. Initial studies using the RatCAP conscious animal PET tomograph

    Energy Technology Data Exchange (ETDEWEB)

    Woody, C. [Brookhaven National Laboratory, Upton, NY (United States)]. E-mail: woody@bnl.gov; Vaska, P. [Brookhaven National Laboratory, Upton, NY (United States); Schlyer, D. [Brookhaven National Laboratory, Upton, NY (United States); Pratte, J.-F. [Brookhaven National Laboratory, Upton, NY (United States); Junnarkar, S. [Brookhaven National Laboratory, Upton, NY (United States); Park, S.-J. [Brookhaven National Laboratory, Upton, NY (United States); Stoll, S. [Brookhaven National Laboratory, Upton, NY (United States); Purschke, M. [Brookhaven National Laboratory, Upton, NY (United States); Southekal, S. [Stony Brook University, Stony Brook, NY (United States); Kriplani, A. [Stony Brook University, Stony Brook, NY (United States); Krishnamoorthy, S. [Stony Brook University, Stony Brook, NY (United States); Maramraju, S. [Stony Brook University, Stony Brook, NY (United States); Lee, D. [Brookhaven National Laboratory, Upton, NY (United States); Schiffer, W. [Brookhaven National Laboratory, Upton, NY (United States); Dewey, S. [Brookhaven National Laboratory, Upton, NY (United States); Neill, J. [Long Island University, Brookville, NY (United States); Kandasamy, A. [Brookhaven National Laboratory, Upton, NY (United States); O' Connor, P. [Brookhaven National Laboratory, Upton, NY (United States); Radeka, V. [Brookhaven National Laboratory, Upton, NY (United States); Fontaine, R. [Sherbrooke University, Sherbrooke, Que. (Canada); Lecomte, R. [Sherbrooke University, Sherbrooke, Que. (Canada)

    2007-02-01

    The RatCAP is a small, head-mounted PET tomograph designed to image the brain of a conscious rat without the use of anesthesia. The detector is a complete, high-performance 3D tomograph consisting of a 3.8 cm inside-diameter ring containing 12 block detectors, each of which is comprised of a 4x8 array of 2.2x2.2x5 mm{sup 3} LSO crystals readout with a matching APD array and custom ASIC, and has a 1.8 cm axial field of view. Construction of the first working prototype detector has been completed and its performance characteristics have been measured. The results show an intrinsic spatial resolution of 2.1 mm, a time resolution of {approx}14 ns FWHM, and a sensitivity of 0.7% at an energy threshold of 150 keV. First preliminary images have been obtained using {sup 18}F-FDG and {sup 11}C-methamphetamine, which show comparable image quality to those obtained from a commercial MicroPET R4 scanner. Initial studies have also been carried out to study stress levels in rats wearing the RatCAP.

  10. Initial studies using the RatCAP conscious animal PET tomograph

    International Nuclear Information System (INIS)

    Woody, C.; Vaska, P.; Schlyer, D.; Pratte, J.-F.; Junnarkar, S.; Park, S.-J.; Stoll, S.; Purschke, M.; Southekal, S.; Kriplani, A.; Krishnamoorthy, S.; Maramraju, S.; Lee, D.; Schiffer, W.; Dewey, S.; Neill, J.; Kandasamy, A.; O'Connor, P.; Radeka, V.; Fontaine, R.; Lecomte, R.

    2007-01-01

    The RatCAP is a small, head-mounted PET tomograph designed to image the brain of a conscious rat without the use of anesthesia. The detector is a complete, high-performance 3D tomograph consisting of a 3.8 cm inside-diameter ring containing 12 block detectors, each of which is comprised of a 4x8 array of 2.2x2.2x5 mm 3 LSO crystals readout with a matching APD array and custom ASIC, and has a 1.8 cm axial field of view. Construction of the first working prototype detector has been completed and its performance characteristics have been measured. The results show an intrinsic spatial resolution of 2.1 mm, a time resolution of ∼14 ns FWHM, and a sensitivity of 0.7% at an energy threshold of 150 keV. First preliminary images have been obtained using 18 F-FDG and 11 C-methamphetamine, which show comparable image quality to those obtained from a commercial MicroPET R4 scanner. Initial studies have also been carried out to study stress levels in rats wearing the RatCAP

  11. Microwave Imaging for Breast Cancer Detection

    DEFF Research Database (Denmark)

    Rubæk, Tonny; Fhager, Andreas; Jensen, Peter Damsgaard

    2011-01-01

    Still more research groups are promoting microwave imaging as a viable supplement or substitution to more conventional imaging modalities. A widespread approach for microwave imaging of the breast is tomographic imaging in which one seeks to reconstruct the distributions of permittivity and condu......Still more research groups are promoting microwave imaging as a viable supplement or substitution to more conventional imaging modalities. A widespread approach for microwave imaging of the breast is tomographic imaging in which one seeks to reconstruct the distributions of permittivity...... and conductivity in the breast. In this paper two nonlinear tomographic algorithms are compared – one is a single-frequency algorithm and the other is a time-domain algorithm....

  12. Clinical usefulness of facial soft tissues thickness measurement using 3D computed tomographic images

    International Nuclear Information System (INIS)

    Jeong, Ho Gul; Kim, Kee Deog; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Han, Seung Ho; Choi, Seong Ho; Kim, Chong Kwan; Park, Chang Seo

    2006-01-01

    To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed: 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analysed by Mann-Whitney test. There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7 mm slice thickness. The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement

  13. A prototype high-resolution animal positron tomograph with avalanche photodiode arrays and LSO crystals

    International Nuclear Information System (INIS)

    Ziegler, S.I.; Pichler, B.J.; Rafecas, M.; Schwaiger, M.

    2001-01-01

    To fully utilize positron emission tomography (PET) as a non-invasive tool for tissue characterization, dedicated instrumentation is being developed which is specially suited for imaging mice and rats. Semiconductor detectors, such as avalanche photodiodes (APDs), may offer an alternative to photomultiplier tubes for the readout of scintillation crystals. Since the scintillation characteristics of lutetium oxyorthosilicate (LSO) are well matched to APDs, the combination of LSO and APDs seems favourable, and the goal of this study was to build a positron tomograph with LSO-APD modules to prove the feasibility of such an approach. A prototype PET scanner based on APD readout of small, individual LSO crystals was developed for tracer studies in mice and rats. The tomograph consists of two sectors (86 mm distance), each comprising three LSO-APD modules, which can be rotated for the acquisition of complete projections. In each module, small LSO crystals (3.7 x 3.7 x 12 mm 3 ) are individually coupled to one channel within matrices containing 2 x 8 square APDs (2.6 x 2.6 mm 2 sensitive area per channel). The list-mode data are reconstructed with a penalized weighted least squares algorithm which includes the spatially dependent line spread function of the tomograph. Basic performance parameters were measured with phantoms and first experiments with rats and mice were conducted to introduce this methodology for biomedical imaging. The reconstructed field of view covers 68 mm, which is 80% of the total detector diameter. Image resolution was shown to be 2.4 mm within the whole reconstructed field of view. Using a lower energy threshold of 450 keV, the system sensitivity was 350 Hz/MBq for a line source in air in the centre of the field of view. In a water-filled cylinder of 4.6 cm diameter, the scatter fraction at the centre of the field of view was 16% (450 keV threshold). The count rate was linear up to 700 coincidence counts per second. In vivo studies of anaesthetized

  14. Computerized tomographic system

    International Nuclear Information System (INIS)

    Godbarsen, R.; Barrett, D.M.; Garrott, P.M.; Foley, L.E.; Redington, R.W.; Lambert, T.W.; Edelheit, L.S.

    1981-01-01

    A computerized tomographic system for examining human breasts is described in detail. Conventional X-ray scanning apparatus has difficulty in achieving the levels of image definition and examination speeds required for mass screening. A novel method of scanning successive layers of the breast with a rotating X-ray beam is discussed and details of the control circuitry and sequence steps are given. The method involves immersing the breast in an inner fluid (e.g. water) filled container which is stationary during an examination and is surrounded by a large outer container which is also filled with the fluid; the inner and outer containers are always maintained at a constant height and the X-ray absorption across the fan-shaped beam is as close as possible to constant. (U.K.)

  15. Detachments of the subducted Indian continental lithosphere based on 3D finite-frequency tomographic images

    Science.gov (United States)

    Liang, X.; Tian, X.; Wang, M.

    2017-12-01

    Indian plate collided with Eurasian plate at 60 Ma and there are about 3000 km crustal shortening since the continental-continental collision. At least one third of the total amount of crustal shortening between Indian and Eurasian plates could not be accounted by thickened Tibetan crust and surface erosion. It will need a combination of possible transfer of lower crust to the mantle by eclogitization and lateral extrusion. Based on the lithosphere-asthenosphere boundary images beneath the Tibetan plateau, there is also at least the same amount deficit for lithospheric mantle subducted into upper/lower mantle or lateral extrusion with the crust. We have to recover a detailed Indian continental lithosphere image beneath the plateau in order to explain this deficit of mass budget. Combining the new teleseismic body waves recorded by SANDWICH passive seismic array with waveforms from several previous temporary seismic arrays, we carried out finite-frequency tomographic inversions to image three-dimensional velocity structures beneath southern and central Tibetan plateau to examine the possible image of subducted Indian lithosphere in the Tibetan upper mantle. We have recovered a continuous high velocity body in upper mantle and piece-wised high velocity anomalies in the mantle transition zone. Based on their geometry and relative locations, we interpreted these high velocity anomalies as the subducted and detached Indian lithosphere at different episodes of the plateau evolution. Detachments of the subducted Indian lithosphere should have a crucial impact on the volcanism activities and uplift history of the plateau.

  16. The Use of Chest Computed Tomographic Angiography in Blunt Trauma Pediatric Population.

    Science.gov (United States)

    Hasadia, Rabea; DuBose, Joseph; Peleg, Kobi; Stephenson, Jacob; Givon, Adi; Kessel, Boris

    2018-02-05

    Blunt chest trauma in children is common. Although rare, associated major thoracic vascular injuries (TVIs) are lethal potential sequelae of these mechanisms. The preferred study for definitive diagnosis of TVI in stable patients is computed tomographic angiography imaging of the chest. This imaging modality is, however, associated with high doses of ionizing radiation that represent significant carcinogenic risk for pediatric patients. The aim of the present investigation was to define the incidence of TVI among blunt pediatric trauma patients in an effort to better elucidate the usefulness of computed tomographic angiography use in this population. A retrospective cohort study was conducted including all blunt pediatric (age blunt trauma victims, 119,821patients were younger than 14 years. Twelve (0.0001%, 12/119821) of these children were diagnosed with TVI. The most common mechanism in this group was pedestrian hit by a car. Mortality was 41.7% (5/12). Thoracic vascular injury is exceptionally rare among pediatric blunt trauma victims but does contribute to the high morbidity and mortality seen with blunt chest trauma. Computed tomographic angiography, with its associated radiation exposure risk, should not be used as a standard tool after trauma in injured children. Clinical protocols are needed in this population to minimize radiation risk while allowing prompt identification of life-threatening injuries.

  17. Advanced Ultrasonic Tomograph of Children's Bones

    Science.gov (United States)

    Lasaygues, Philippe; Lefebvre, Jean-Pierre; Guillermin, Régine; Kaftandjian, Valérie; Berteau, Jean-Philippe; Pithioux, Martine; Petit, Philippe

    This study deals with the development of an experimental device for performing ultrasonic computed tomography (UCT) on bone in pediatric degrees. The children's bone tomographs obtained in this study, were based on the use of a multiplexed 2-D ring antenna (1 MHz and 3 MHz) designed for performing electronic and mechanical scanning. Although this approach is known to be a potentially valuable means of imaging objects with similar acoustical impedances, problems arise when quantitative images of more highly contrasted media such as bones are required. Various strategies and various mathematical procedures for modeling the wave propagation based on Born approximations have been developed at our laboratory, which are suitable for use with pediatric cases. Inversions of the experimental data obtained are presented.

  18. Estimating multi-phase pore-scale characteristics from X-ray tomographic data using cluster analysis-based segmentation

    DEFF Research Database (Denmark)

    Wildenschild, D.; Culligan, K.A.; Christensen, Britt Stenhøj Baun

    2006-01-01

    present in grey-scale X-ray tomographic images. The approach is based on a cluster analysis technique, used in combination with various other filtering and skeletonization schemes. We apply this segmentation algorithm to analyze multiphase pore-scale flow subjects such as hysteresis and interfacial...... characterization. The results clearly illustrate the advantage of using X-ray tomography together with cluster analysis-based image processing techniques. We were able to obtain detailed information on pore scale distribution of air and water phases, as well as quantitative measures of air bubble size and air...... of individual pores and interfaces. However, separation of the various phases (fluids and solids) in the grey-scale tomographic images has posed a major problem to quantitative analysis of the data. We present an image processing technique that facilitates identification and separation of the various phases...

  19. Crustal tomographic imaging and geodynamic implications toward south of Southern Granulite Terrain (SGT), India

    Science.gov (United States)

    Behera, Laxmidhar

    2011-09-01

    The crustal structure toward southern part of SGT is poorly defined leaving an opportunity to understand the tectonic and geodynamic evolution of this high-grade granulite terrain surrounded by major shear and tectonically disturbed zones like Achankovil Shear Zone (AKSZ) and Palghat Cauvery Shear Zone (PCSZ). To develop a geologically plausible crustal tectonic model depicting major structural elements, a comprehensive tomographic image was derived using deep-seismic-sounding data corroborated by Bouguer gravity modeling, coincident-reflection-seismic, heat-flow and available geological/geochronological informations along the N-S trending Vattalkundu-Kanyakumari geotransect. The final tectonic model represents large compositional changes of subsurface rocks accompanied by velocity heterogeneities with crustal thinning (44-36 km) and Moho upwarping from north to south. This study also reveals and successfully imaged anomalous zone of exhumation near AKSZ having transpression of exhumed rocks at mid-to-lower crustal level (20-30 km) with significant underplating and mantle upwelling forming a complex metamorphic province. The presence of shear zones with high-grade charnockite massifs in the upper-crust exposed in several places reveal large scale exhumation of granulites during the Pan-African rifting (~ 550 Ma) and provide important insights of plume-continental lithosphere interaction with reconstruction of the Gondwanaland.

  20. Evaluation of image-guidance protocols in the treatment of head and neck cancers

    International Nuclear Information System (INIS)

    Zeidan, Omar A.; Langen, Katja M.; Meeks, Sanford L.; Manon, Rafael R.; Wagner, Thomas H.; Willoughby, Twyla R.; Jenkins, D. Wayne; Kupelian, Patrick A.

    2007-01-01

    Purpose: The aim of this study was to assess the residual setup error of different image-guidance (IG) protocols in the alignment of patients with head and neck cancer. The protocols differ in the percentage of treatment fractions that are associated with image guidance. Using data from patients who were treated with daily IG, the residual setup errors for several different protocols are retrospectively calculated. Methods and Materials: Alignment data from 24 patients (802 fractions) treated with daily IG on a helical tomotherapy unit were analyzed. The difference between the daily setup correction and the setup correction that would have been made according to a specific protocol was used to calculate the residual setup errors for each protocol. Results: The different protocols are generally effective in reducing systematic setup errors. Random setup errors are generally not reduced for fractions that are not image guided. As a consequence, if every other treatment is image guided, still about 11% of all treatments (IG and not IG) are subject to three-dimensional setup errors of at least 5 mm. This frequency increases to about 29% if setup errors >3 mm are scored. For various protocols that require 15% to 31% of the treatments to be image guided, from 50% to 60% and from 26% to 31% of all fractions are subject to setup errors >3 mm and >5 mm, respectively. Conclusion: Residual setup errors reduce with increasing frequency of IG during the course of external-beam radiotherapy for head-and-neck cancer patients. The inability to reduce random setup errors for fractions that are not image guided results in notable residual setup errors

  1. 76 FR 51993 - Draft Guidance for Industry on Standards for Clinical Trial Imaging Endpoints; Availability

    Science.gov (United States)

    2011-08-19

    ... clinical trials of therapeutic drugs and biological products. The draft guidance describes standards... important imaging endpoint is used in a clinical trial of a therapeutic drug or biological product... Services to the Chairman of [[Page 51994

  2. In vivo tomographic imaging of lung colonization of tumour in mouse with simultaneous fluorescence and X-ray CT.

    Science.gov (United States)

    Zhang, Bin; Gao, Fuping; Wang, Mengjiao; Cao, Xu; Liu, Fei; Wang, Xin; Luo, Jianwen; Wang, Guangzhi; Bai, Jing

    2014-01-01

    Non-invasive in vivo imaging of diffuse and wide-spread colonization within the lungs, rather than distinct solid primary tumors, is still a challenging work. In this work, a lung colonization mouse model bearing A549 human lung tumor was simultaneously scanned by a dual-modality fluorescence molecular tomography (FMT) and X-ray computed tomography (CT) system in vivo. A two steps method which incorporates CT structural information into the FMT reconstruction procedure is employed to provide concurrent anatomical and functional information. By using the target-specific fluorescence agent, the fluorescence tomographic results show elevated fluorescence intensity deep within the lungs which is colonized with diffuse and wide-spread tumors. The results were confirmed with ex vivo fluorescence reflectance imaging and histological examination of the lung tissues. With FMT reconstruction combined with the CT information, the dual-modality FMT/micro-CT system is expected to offer sensitive and noninvasive imaging of diffuse tumor colonization within the lungs in vivo. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Condylar guidance: correlation between protrusive interocclusal record and panoramic radiographic image: a pilot study.

    Science.gov (United States)

    Tannamala, Pavan Kumar; Pulagam, Mahesh; Pottem, Srinivas R; Swapna, B

    2012-04-01

    The purpose of this study was to compare the sagittal condylar angles set in the Hanau articulator by use of a method of obtaining an intraoral protrusive record to those angles found using a panoramic radiographic image. Ten patients, free of signs and symptoms of temporomandibular disorder and with intact dentition were selected. The dental stone casts of the subjects were mounted on a Hanau articulator with a springbow and poly(vinyl siloxane) interocclusal records. For all patients, the protrusive records were obtained when the mandible moved forward by approximately 6 mm. All procedures for recording, mounting, and setting were done in the same session. The condylar guidance angles obtained were tabulated. A panoramic radiographic image of each patient was made with the Frankfurt horizontal plane parallel to the floor of the mouth. Tracings of the radiographic images were made. The horizontal reference line was marked by joining the orbitale and porion. The most superior and most inferior points of the curvatures were identified. These two lines were connected by a straight line representing the mean curvature line. Angles made by the intersection of the mean curvature line and the horizontal reference line were measured. The results were subjected to statistical analysis with a significance level of p record method. The mean condylar guidance angle between the right and left side by both the methods was not statistically significant. The comparison of mean condylar guidance angles between the right side of the protrusive record method and the right side of the panoramic radiographic method and the left side of the protrusive record method and the left side of the panoramic radiographic method (p= 0.071 and p= 0.057, respectively) were not statistically significant. Within the limitations of this study, it was concluded that the protrusive condylar guidance angles obtained by panoramic radiograph may be used in programming semi-adjustable articulators. © 2012

  4. Standardization of the first-trimester fetal cardiac examination using spatiotemporal image correlation with tomographic ultrasound and color Doppler imaging.

    Science.gov (United States)

    Turan, S; Turan, O M; Ty-Torredes, K; Harman, C R; Baschat, A A

    2009-06-01

    The challenges of the first-trimester examination of the fetal heart may in part be overcome by technical advances in three-dimensional (3D) ultrasound techniques. Our aim was to standardize the first-trimester 3D imaging approach to the cardiac examination to provide the most consistent and accurate display of anatomy. Low-risk women with normal findings on first-trimester screening at 11 to 13 + 6 weeks had cardiac ultrasound using the following sequence: (1) identification of the four-chamber view; (2) four-dimensional (4D) volume acquisition with spatiotemporal image correlation (STIC) and color Doppler imaging (angle = 20 degrees, sweep 10 s); (3) offline, tomographic ultrasound imaging (TUI) analysis with standardized starting plane (four-chamber view), slice number and thickness; (4) assessment of fetal cardiac anatomy (four-chamber view, cardiac axis, size and symmetry, atrioventricular valves, great arteries and descending aorta) with and without color Doppler. 107 consecutive women (age, 16-42 years, body mass index 17.2-50.2 kg/m(2)) were studied. A minimum of three 3D volumes were obtained for each patient, transabdominally in 91.6%. Fetal motion artifact required acquisition of more than three volumes in 20%. The median time for TUI offline analysis was 100 (range, 60-240) s. Individual anatomic landmarks were identified in 89.7-99.1%. Visualization of all structures in one panel was observed in 91 patients (85%). Starting from a simple two-dimensional cardiac landmark-the four-chamber view-the standardized STIC-TUI technique enables detailed segmental cardiac evaluation of the normal fetal heart in the first trimester. (c) 2009 ISUOG.

  5. Ultrasound and PET-CT image fusion for prostate brachytherapy image guidance

    International Nuclear Information System (INIS)

    Hasford, F.

    2015-01-01

    , indicating the system’s ability to visualize low contrast objects 5.4 cm into a patient. PET-CT system’s performance evaluation also produced satisfactory results in accordance with set tolerances as recommended by IAEA Human Health Series 1. Computed tomography laser alignment test ensured that all CT gantry lasers were properly aligned with the patient bed. Image display width test ensured that volume of patient or organ being measured and displayed was equivalent to that selected on the CT scanner console, to a deviation of ± 1 mm. Results from CT image uniformity test showed that mean CT numbers in peripheral regions of interest deviated from the central mean to within recommended tolerance level of ± 5 HU, indicating a good level of uniformity. Computed tomographic dose indices for head and body phantoms were estimated as 44.30 mGy and 20.08 mGy, comparative to console displayed doses of 42.40 mGy and 19.49 mGy respectively. Registration accuracy for PET-CT images was to have displacements of less than 1 mm in x, y and z directions. Image quality of PET-CT images was performed to produce images simulating those obtained in a total body imaging study involving both hot and cold lesions. Percentage contrast estimates of 49.3% and 52.6% were obtained for hot spheres of diameters 1.3 cm and 2.2 cm respectively, while contrast estimates of 74.8% and 75.6% were obtained for cold spheres of diameters 2.8 cm and 3.7 cm respectively. The PET-CT system resolution was estimated as 0.5 ± 0.01 cm, indicating the system’s ability to image tumours of the size of about 5 mm. Satisfactory results from the performance evaluation of ultrasound and PET-CT systems, paved way for them to be used in acquiring prostatic images for the study. Developed MATLAB image enhancement algorithm enhanced the quality of prostatic images before fusion. The algorithm was developed by mapping the intensity values in raw images to new values in a modified image using imadjust function. Contrast

  6. Directional fine structure in absorption of white x rays: A tomographic interpretation

    International Nuclear Information System (INIS)

    Korecki, P.; Szymonski, M.; Tolkiehn, M.; Novikov, D. V.; Materlik, G.

    2006-01-01

    We discuss directional fine structure in absorption of white x rays for tomographic imaging of crystal structure at the atomic level. The interference between a direct x-ray beam and the secondary waves coherently scattered inside a specimen modifies the total wave field at the position of the absorbing atoms. For a white x-ray beam, the wave field variations cancel out by energy integration for all directions, except for the near forward scattering components, coinciding with the incident beam. Therefore, two-dimensional patterns of the angular-dependent fine structure in absorption of white x rays can be interpreted as real-space projections of atomic structure. In this work, we present a theory describing the directional fine structure in white x-ray absorption and a tomographic approach for crystal structure retrieval developed on its basis. The tomographic algorithm is applied to the experimental x-ray absorption data recorded for GaP crystals

  7. Comparative study of adenosine and exercise 201Tl myocardial perfusion tomographic imaging for detection of coronary heart disease

    International Nuclear Information System (INIS)

    Wang Xiong

    1997-01-01

    To compare diagnostic accuracy of adenosine and exercise 201 Tl myocardial perfusion tomographic imaging for detection of coronary heart disease (CHD) in patients with a normal rest ECG and no history of myocardial infarction, 81 patients with CHD and 10 normal control subjects underwent adenosine myocardial perfusion imaging, exercise nuclide myocardial perfusion imaging was performed in 117 patients with CHD and 16 normal control subjects, two groups also had coronary arteriography. Both exercise and adenosine testing parameters were analysed. It is shown: 1) The sensitivity and specificity for detection of CHD were 79% vs 80% for adenosine group and 81% vs 81% for exercise myocardial perfusion imaging group respectively. There was no significant difference in comparison with two matched groups (χ 2 = 1.13, χ 2 = 0.18, χ 2 = 0.12, P>0.05). 2) Side effects induced by adenosine accounted for 89% of patients, all symptoms were mild and disappeared quickly after the termination of the study except in 2 cases withdrawal of infusion needed because of severe angina pectoris. Adenosine myocardial perfusion imaging is a safe and sensitive method for detection of CHD. The diagnostic value of adenosine test is similar to that of exercise myocardial perfusion imaging and particularly useful in evaluating patients unable to perform exercise test or achieve adequate level of exercise

  8. A general purpose tomographic program with combined inversions

    International Nuclear Information System (INIS)

    Xu Wenbin; Dong Jiafu; Li Fanzhu

    1996-01-01

    A general tomographic program has been developed by combining the Bessel expansion with the Zernicke expansion. It is useful for studying of the magnetic island structure of the tearing mode and in reconstructing the density profiles of impurities in tokamak plasmas. This combined method have the advantages of both expansions, i.e. there will be no spurious images in the edge and it will be of high inverse precision in the center of plasma

  9. Tomographic PIV: particles versus blobs

    International Nuclear Information System (INIS)

    Champagnat, Frédéric; Cornic, Philippe; Besnerais, Guy Le; Plyer, Aurélien; Cheminet, Adam; Leclaire, Benjamin

    2014-01-01

    We present an alternative approach to tomographic particle image velocimetry (tomo-PIV) that seeks to recover nearly single voxel particles rather than blobs of extended size. The baseline of our approach is a particle-based representation of image data. An appropriate discretization of this representation yields an original linear forward model with a weight matrix built with specific samples of the system’s point spread function (PSF). Such an approach requires only a few voxels to explain the image appearance, therefore it favors much more sparsely reconstructed volumes than classic tomo-PIV. The proposed forward model is general and flexible and can be embedded in a classical multiplicative algebraic reconstruction technique (MART) or a simultaneous multiplicative algebraic reconstruction technique (SMART) inversion procedure. We show, using synthetic PIV images and by way of a large exploration of the generating conditions and a variety of performance metrics, that the model leads to better results than the classical tomo-PIV approach, in particular in the case of seeding densities greater than 0.06 particles per pixel and of PSFs characterized by a standard deviation larger than 0.8 pixels. (paper)

  10. Tomographic phase analysis to detect the site of accessory conduction pathway in Wolff-Parkinson-White syndrome

    International Nuclear Information System (INIS)

    Nakajima, K.; Bunko, H.; Tada, A.; Tonami, N.; Taki, J.; Nanbu, I.; Hisada, K.; Misaki, T.; Iwa, T.

    1984-01-01

    Phase analysis has been applied to Wolff-Parkinson-White syndrome (WPW) to detect the site of accessory conduction pathway (ACP); however, there was a limitation to estimate the precise location of ACP by planar phase analysis. In this study, the authors applied phase analysis to gated blood pool tomography. Twelve patients with WPW who underwent epicardial mapping and surgical division of ACP were studied by both of gated emission computed tomography (GECT) and routine gated blood pool study (GBPS). The GBPS was performed with Tc-99m red blood cells in multiple projections; modified left anterior oblique, right anterior oblique and/or left lateral views. In GECT, short axial, horizontal and vertical long axial blood pool images were reconstructed. Phase analysis was performed using fundamental frequency of the Fourier transform in both GECT and GBPS images, and abnormal initial contractions on both the planar and tomographic phase analysis were compared with the location of surgically confirmed ACPs. In planar phase analysis, abnormal initial phase was identified in 7 out of 12 (58%) patients, while in tomographic phase analysis, the localization of ACP was predicted in 11 out of 12 (92%) patients. Tomographic phase analysis is superior to planar phase images in 8 out of 12 patients to estimate the location of ACP. Phase analysis by GECT can avoid overlap of blood pool in cardiac chambers and has advantage to identify the propagation of phase three-dimensionally. Tomographic phase analysis is a good adjunctive method for patients with WPW to estimate the site of ACP

  11. Tomographic phase analysis to detect the site of accessory conduction pathway in Wolff-Parkinson-White syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, K.; Bunko, H.; Tada, A.; Tonami, N.; Taki, J.; Nanbu, I.; Hisada, K.; Misaki, T.; Iwa, T.

    1984-01-01

    Phase analysis has been applied to Wolff-Parkinson-White syndrome (WPW) to detect the site of accessory conduction pathway (ACP); however, there was a limitation to estimate the precise location of ACP by planar phase analysis. In this study, the authors applied phase analysis to gated blood pool tomography. Twelve patients with WPW who underwent epicardial mapping and surgical division of ACP were studied by both of gated emission computed tomography (GECT) and routine gated blood pool study (GBPS). The GBPS was performed with Tc-99m red blood cells in multiple projections; modified left anterior oblique, right anterior oblique and/or left lateral views. In GECT, short axial, horizontal and vertical long axial blood pool images were reconstructed. Phase analysis was performed using fundamental frequency of the Fourier transform in both GECT and GBPS images, and abnormal initial contractions on both the planar and tomographic phase analysis were compared with the location of surgically confirmed ACPs. In planar phase analysis, abnormal initial phase was identified in 7 out of 12 (58%) patients, while in tomographic phase analysis, the localization of ACP was predicted in 11 out of 12 (92%) patients. Tomographic phase analysis is superior to planar phase images in 8 out of 12 patients to estimate the location of ACP. Phase analysis by GECT can avoid overlap of blood pool in cardiac chambers and has advantage to identify the propagation of phase three-dimensionally. Tomographic phase analysis is a good adjunctive method for patients with WPW to estimate the site of ACP.

  12. Performance of analytical methods for tomographic gamma scanning

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Mercer, D.J.

    1997-01-01

    The use of gamma-ray computerized tomography for nondestructive assay of radioactive materials has led to the development of specialized analytical methods. Over the past few years, Los Alamos has developed and implemented a computer code, called ARC-TGS, for the analysis of data obtained by tomographic gamma scanning (TGS). ARC-TGS reduces TGS transmission and emission tomographic data, providing the user with images of the sample contents, the activity or mass of selected radionuclides, and an estimate of the uncertainty in the measured quantities. The results provided by ARC-TGS can be corrected for self-attenuation when the isotope of interest emits more than one gamma-ray. In addition, ARC-TGS provides information needed to estimate TGS quantification limits and to estimate the scan time needed to screen for small amounts of radioactivity. In this report, an overview of the analytical methods used by ARC-TGS is presented along with an assessment of the performance of these methods for TGS

  13. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The principal problem in trans-axial tomographic radioisotope scanning is the length of time required to obtain meaningful data. Patient movement and radioisotope migration during the scanning period can cause distortion of the image. The object of this invention is to reduce the scanning time without degrading the images obtained. A system is described in which a scintillation camera detector is moved to an orbit about the cranial-caudal axis relative to the patient. A collimator is used in which lead septa are arranged so as to admit gamma rays travelling perpendicular to this axis with high spatial resolution and those travelling in the direction of the axis with low spatial resolution, thus increasing the rate of acceptance of radioactive events to contribute to the positional information obtainable without sacrificing spatial resolution. (author)

  14. Clamshell tomograph

    International Nuclear Information System (INIS)

    Derenzo, S. E.; Budinger, Th. F.

    1984-01-01

    In brief, the invention is a tomograph modified to be in a clamshell configuration so that the ring or rings may be moved to multiple sampling positions. The tomograph includes an array of detectors arranged in successive adjacent relative locations along a closed curve in a first position in a selected plane, and means for securing the detectors in the relative locations in a first sampling position. The securing means is movable in the plane in two sections and pivotable at one point and only one point to enable movement of at least one of the sections to a second sampling position out of the closed curve so that the ends of the section which are opposite the point are moved apart a predetermined space

  15. Field experience with a mobile tomographic nondestructive assay system

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Betts, S.E.; Taggart, D.P.; Estep, R.J.; Nicholas, N.J.; Lucas, M.C.; Harlan, R.A.

    1995-01-01

    A mobile tomographic gamma-ray scanner (TGS) developed by Los Alamos National Laboratory was recently demonstrated at the Rocky Flats Environmental Technology Site and is currently in use at Los Alamos waste storage areas. The scanner was developed to assay radionuclides in low-level, transuranic, and mixed waste in containers ranging in size from 2 ft 3 boxes to 83-gallon overpacks. The tomographic imaging capability provides a complete correction for source distribution and matrix attenuation effects, enabling accurate assays of Pu-239 and other gamma-ray emitting isotopes. In addition, the system can reliably detect self-absorbing material such as plutonium metal shot, and can correct for bias caused by self-absorption. The system can be quickly configured to execute far-field scans, segmented gamma-ray scans, and a host of intermediate scanning protocols, enabling higher throughput (up to 20 drums per 8-hour shift). In this paper, we will report on the results of field trials of the mobile system at Rocky Flats and Los Alamos. Assay accuracy is confirmed for cases in which TGS assays can be compared with assays (e.g. with calorimetry) of individual packages within the drums. The mobile tomographic technology is expected to considerably reduce characterization costs at DOE production and environmental technology sites

  16. Fusion imaging of computed tomographic pulmonary angiography and SPECT ventilation/perfusion scintigraphy: initial experience and potential benefit

    International Nuclear Information System (INIS)

    Harris, Benjamin; Bailey, Dale; Roach, Paul; Bailey, Elizabeth; King, Gregory

    2007-01-01

    The objective of this study was to examine the feasibility of fusing ventilation and perfusion data from single-photon emission computed tomography (SPECT) ventilation perfusion (V/Q) scintigraphy together with computed tomographic pulmonary angiography (CTPA) data. We sought to determine the accuracy of this fusion process. In addition, we correlated the findings of this technique with the final clinical diagnosis. Thirty consecutive patients (17 female, 13 male) who had undergone both CTPA and SPECT V/Q scintigraphy during their admission for investigation of potential pulmonary embolism were identified retrospectively. Image datasets from these two modalities were co-registered and fused using commercial software. Accuracy of the fusion process was determined subjectively by correlation between modalities of the anatomical boundaries and co-existent pleuro-parenchymal abnormalities. In all 30 cases, SPECT V/Q images were accurately fused with CTPA images. An automated registration algorithm was sufficient alone in 23 cases (77%). Additional linear z-axis scaling was applied in seven cases. There was accurate topographical co-localisation of vascular, parenchymal and pleural disease on the fused images. Nine patients who had positive CTPA performed as an initial investigation had co-localised perfusion defects on the subsequent fused CTPA/SPECT images. Three of the 11 V/Q scans initially reported as intermediate could be reinterpreted as low probability owing to co-localisation of defects with parenchymal or pleural pathology. Accurate fusion of SPECT V/Q scintigraphy to CTPA images is possible. This technique may be clinically useful in patients who have non-diagnostic initial investigations or in whom corroborative imaging is sought. (orig.)

  17. Interpretation of computed tomographic images

    International Nuclear Information System (INIS)

    Stickle, R.L.; Hathcock, J.T.

    1993-01-01

    This article discusses the production of optimal CT images in small animal patients as well as principles of radiographic interpretation. Technical factors affecting image quality and aiding image interpretation are included. Specific considerations for scanning various anatomic areas are given, including indications and potential pitfalls. Principles of radiographic interpretation are discussed. Selected patient images are illustrated

  18. Simulation of Tomographic Reconstruction of Magnetosphere Plasma Distribution By Multi-spacecraft Systems.

    Science.gov (United States)

    Kunitsyn, V.; Nesterov, I.; Andreeva, E.; Zelenyi, L.; Veselov, M.; Galperin, Y.; Buchner, J.

    A satellite radiotomography method for electron density distributions was recently proposed for closely-space multi-spacecraft group of high-altitude satellites to study the physics of reconnection process. The original idea of the ROY project is to use a constellation of spacecrafts (one main and several sub-satellites) in order to carry out closely-spaced multipoint measurements and 2D tomographic reconstruction of elec- tron density in the space between the main satellite and the subsatellites. The distances between the satellites were chosen to vary from dozens to few hundreds of kilometers. The easiest data interpretation is achieved when the subsatellites are placed along the plasma streamline. Then, whenever a plasma density irregularity moves between the main satellite and the subsatellites it will be scanned in different directions and we can get 2D distribution of plasma using these projections. However in general sub- satellites are not placed exactly along the plasma streamline. The method of plasma velocity determination relative to multi-spacecraft systems is considered. Possibilities of 3D tomographic imaging using multi-spacecraft systems are analyzed. The model- ing has shown that efficient scheme for 3D tomographic imaging would be to place spacecrafts in different planes so that the angle between the planes would make not more then ten degrees. Work is supported by INTAS PROJECT 2000-465.

  19. Endovascular interventional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Bartels, L W; Bakker, C J G

    2003-01-01

    Minimally invasive interventional radiological procedures, such as balloon angioplasty, stent placement or coiling of aneurysms, play an increasingly important role in the treatment of patients suffering from vascular disease. The non-destructive nature of magnetic resonance imaging (MRI), its ability to combine the acquisition of high quality anatomical images and functional information, such as blood flow velocities, perfusion and diffusion, together with its inherent three dimensionality and tomographic imaging capacities, have been advocated as advantages of using the MRI technique for guidance of endovascular radiological interventions. Within this light, endovascular interventional MRI has emerged as an interesting and promising new branch of interventional radiology. In this review article, the authors will give an overview of the most important issues related to this field. In this context, we will focus on the prerequisites for endovascular interventional MRI to come to maturity. In particular, the various approaches for device tracking that were proposed will be discussed and categorized. Furthermore, dedicated MRI systems, safety and compatibility issues and promising applications that could become clinical practice in the future will be discussed. (topical review)

  20. Accuracy of image guidance using free-breathing cone-beam computed tomography for stereotactic lung radiotherapy.

    Science.gov (United States)

    Kamomae, Takeshi; Monzen, Hajime; Nakayama, Shinichi; Mizote, Rika; Oonishi, Yuuichi; Kaneshige, Soichiro; Sakamoto, Takashi

    2015-01-01

    Movement of the target object during cone-beam computed tomography (CBCT) leads to motion blurring artifacts. The accuracy of manual image matching in image-guided radiotherapy depends on the image quality. We aimed to assess the accuracy of target position localization using free-breathing CBCT during stereotactic lung radiotherapy. The Vero4DRT linear accelerator device was used for the examinations. Reference point discrepancies between the MV X-ray beam and the CBCT system were calculated using a phantom device with a centrally mounted steel ball. The precision of manual image matching between the CBCT and the averaged intensity (AI) images restructured from four-dimensional CT (4DCT) was estimated with a respiratory motion phantom, as determined in evaluations by five independent operators. Reference point discrepancies between the MV X-ray beam and the CBCT image-guidance systems, categorized as left-right (LR), anterior-posterior (AP), and superior-inferior (SI), were 0.33 ± 0.09, 0.16 ± 0.07, and 0.05 ± 0.04 mm, respectively. The LR, AP, and SI values for residual errors from manual image matching were -0.03 ± 0.22, 0.07 ± 0.25, and -0.79 ± 0.68 mm, respectively. The accuracy of target position localization using the Vero4DRT system in our center was 1.07 ± 1.23 mm (2 SD). This study experimentally demonstrated the sufficient level of geometric accuracy using the free-breathing CBCT and the image-guidance system mounted on the Vero4DRT. However, the inter-observer variation and systematic localization error of image matching substantially affected the overall geometric accuracy. Therefore, when using the free-breathing CBCT images, careful consideration of image matching is especially important.

  1. Observer Evaluation of a Metal Artifact Reduction Algorithm Applied to Head and Neck Cone Beam Computed Tomographic Images

    Energy Technology Data Exchange (ETDEWEB)

    Korpics, Mark; Surucu, Murat; Mescioglu, Ibrahim; Alite, Fiori; Block, Alec M.; Choi, Mehee; Emami, Bahman; Harkenrider, Matthew M.; Solanki, Abhishek A.; Roeske, John C., E-mail: jroeske@lumc.edu

    2016-11-15

    Purpose and Objectives: To quantify, through an observer study, the reduction in metal artifacts on cone beam computed tomographic (CBCT) images using a projection-interpolation algorithm, on images containing metal artifacts from dental fillings and implants in patients treated for head and neck (H&N) cancer. Methods and Materials: An interpolation-substitution algorithm was applied to H&N CBCT images containing metal artifacts from dental fillings and implants. Image quality with respect to metal artifacts was evaluated subjectively and objectively. First, 6 independent radiation oncologists were asked to rank randomly sorted blinded images (before and after metal artifact reduction) using a 5-point rating scale (1 = severe artifacts; 5 = no artifacts). Second, the standard deviation of different regions of interest (ROI) within each image was calculated and compared with the mean rating scores. Results: The interpolation-substitution technique successfully reduced metal artifacts in 70% of the cases. From a total of 60 images from 15 H&N cancer patients undergoing image guided radiation therapy, the mean rating score on the uncorrected images was 2.3 ± 1.1, versus 3.3 ± 1.0 for the corrected images. The mean difference in ranking score between uncorrected and corrected images was 1.0 (95% confidence interval: 0.9-1.2, P<.05). The standard deviation of each ROI significantly decreased after artifact reduction (P<.01). Moreover, a negative correlation between the mean rating score for each image and the standard deviation of the oral cavity and bilateral cheeks was observed. Conclusion: The interpolation-substitution algorithm is efficient and effective for reducing metal artifacts caused by dental fillings and implants on CBCT images, as demonstrated by the statistically significant increase in observer image quality ranking and by the decrease in ROI standard deviation between uncorrected and corrected images.

  2. Assessment in dogs tympanic bulla, through virtual tomographic endoscopy; Avaliacao de bulas timpanicas em caes, por meio da endoscopia tomografica virtual

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luciana Carandina da; Sabino, Emanuelle Guidugli, E-mail: lucianacarandina@uol.com.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria. Dept. de Reproducao Animal e Radiologia Veterinaria; Vulcano, Luiz Carlos; Machado, Vania Maria de Vasconcelos [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina Veterinaria

    2012-07-01

    Dogs usually have problems related to the auditory canal. For the diagnosis of these pathologies, it is necessary a physical examination and, in some cases radiographic examination and computed tomography. The tympanic bulla is not easily visualized radiographically, since there is many structures of the brain overlaying the image obtained. The computed tomography has been the technique of choice to assess this structure faithfully. A new alternative assessment of the tympanic bulla is tomographic virtual endoscopy, which allows an improvement of the image obtained through the virtual tomographic technique. This paper provides information on the use of computed tomography, and a new technique, tomographic virtual endoscopy, in order to make the improvement of these techniques, and prove the reliability of these changes in the diagnosis of ear canals of dogs. Therefore, we performed the computed tomography of the tympanic bulla on healthy animals, and later performed image reconstruction in three-dimensional (3D) mode for virtual endoscopy. (author)

  3. A Penalization Approach for Tomographic Reconstruction of Binary Axially Symmetric Objects

    International Nuclear Information System (INIS)

    Abraham, R.; Bergounioux, M.; Trelat, E.

    2008-01-01

    We propose a variational method for tomographic reconstruction of blurred and noised binary images based on a penalization process of a minimization problem settled in the space of bounded variation functions. We prove existence and/or uniqueness results and derive a penalized optimality system. Numerical simulations are provided to demonstrate the relevance of the approach

  4. 3D/3D registration of coronary CTA and biplane XA reconstructions for improved image guidance

    Energy Technology Data Exchange (ETDEWEB)

    Dibildox, Gerardo, E-mail: g.dibildox@erasmusmc.nl; Baka, Nora; Walsum, Theo van [Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands); Punt, Mark; Aben, Jean-Paul [Pie Medical Imaging, 6227 AJ Maastricht (Netherlands); Schultz, Carl [Department of Cardiology, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands); Niessen, Wiro [Quantitative Imaging Group, Faculty of Applied Sciences, Delft University of Technology, 2628 CJ Delft, The Netherlands and Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands)

    2014-09-15

    Purpose: The authors aim to improve image guidance during percutaneous coronary interventions of chronic total occlusions (CTO) by providing information obtained from computed tomography angiography (CTA) to the cardiac interventionist. To this end, the authors investigate a method to register a 3D CTA model to biplane reconstructions. Methods: The authors developed a method for registering preoperative coronary CTA with intraoperative biplane x-ray angiography (XA) images via 3D models of the coronary arteries. The models are extracted from the CTA and biplane XA images, and are temporally aligned based on CTA reconstruction phase and XA ECG signals. Rigid spatial alignment is achieved with a robust probabilistic point set registration approach using Gaussian mixture models (GMMs). This approach is extended by including orientation in the Gaussian mixtures and by weighting bifurcation points. The method is evaluated on retrospectively acquired coronary CTA datasets of 23 CTO patients for which biplane XA images are available. Results: The Gaussian mixture model approach achieved a median registration accuracy of 1.7 mm. The extended GMM approach including orientation was not significantly different (P > 0.1) but did improve robustness with regards to the initialization of the 3D models. Conclusions: The authors demonstrated that the GMM approach can effectively be applied to register CTA to biplane XA images for the purpose of improving image guidance in percutaneous coronary interventions.

  5. Effect of Donepezil on Wernicke Aphasia After Bilateral Middle Cerebral Artery Infarction: Subtraction Analysis of Brain F-18 Fluorodeoxyglucose Positron Emission Tomographic Images.

    Science.gov (United States)

    Yoon, Seo Yeon; Kim, Je-Kyung; An, Young-Sil; Kim, Yong Wook

    2015-01-01

    Aphasia is one of the most common neurologic deficits occurring after stroke. Although the speech-language therapy is a mainstream option for poststroke aphasia, pharmacotherapy is recently being tried to modulate different neurotransmitter systems. However, the efficacy of those treatments is still controversial. We present a case of a 53-year-old female patient with Wernicke aphasia, after the old infarction in the territory of left middle cerebral artery for 8 years and the recent infarction in the right middle cerebral artery for 4 months. On the initial evaluation, the Aphasia Quotient in Korean version of the Western Aphasia Battery was 25.6 of 100. Baseline brain F-18 fluorodeoxyglucose positron emission tomographic images demonstrated a decreased cerebral metabolism in the left temporoparietal area and right temporal lobe. Donepezil hydrochloride, a reversible acetylcholinesterase inhibitor, was orally administered 5 mg/d for 6 weeks after the initial evaluation and was increased to 10 mg/d for the following 6 weeks. After the donepezil treatment, the patient showed improvement in language function, scoring 51.0 of 100 on Aphasia Quotient. A subtraction analysis of the brain F-18 fluorodeoxyglucose positron emission tomographic images after donepezil medication demonstrated increased uptake in both middle temporal gyri, extended to the occipital area and the left cerebellum. Thus, we suggest that donepezil can be an effective therapeutic choice for the treatment of Wernicke aphasia.

  6. Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance

    International Nuclear Information System (INIS)

    Sveistrup, Joen; Rosenschöld, Per Munck af; Deasy, Joseph O; Oh, Jung Hun; Pommer, Tobias; Petersen, Peter Meidahl; Engelholm, Svend Aage

    2014-01-01

    Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1–2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5–7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p < 0.001). For GU toxicity the numbers were 41.8% and 29.7%, respectively (p = 0.011). On multivariate analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p < 0.001, HR = 11.59 [CI: 6.67-20.14]). 3DCRT was also associated with an increased risk of developing GU toxicity compared to IG-IMRT. The 3-year actuarial biochemical progression-free survival probability was 86.0% for 3DCRT and 90.3% for IG-IMRT (p = 0.386). On multivariate analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction

  7. 256-Slice coronary computed tomographic angiography in patients with atrial fibrillation: optimal reconstruction phase and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Seitaro; Yuki, Hideaki; Kidoh, Masafumi; Utsunomiya, Daisuke; Nakaura, Takeshi; Namimoto, Tomohiro; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Faculty of Life Sciences, Chuou-ku, Kumamoto (Japan); Honda, Keiichi; Yoshimura, Akira; Katahira, Kazuhiro [Kumamoto Chuo Hospital, Department of Diagnostic Radiology, Minami-ku, Kumamoto (Japan); Noda, Katsuo; Oshima, Shuichi [Kumamoto Chuo Hospital, Department of Cardiology, Minami-ku, Kumamoto (Japan)

    2016-01-15

    To assess the optimal reconstruction phase and the image quality of coronary computed tomographic angiography (CCTA) in patients with atrial fibrillation (AF). We performed CCTA in 60 patients with AF and 60 controls with sinus rhythm. The images were reconstructed in multiple phases in all parts of the cardiac cycle, and the optimal reconstruction phase with the fewest motion artefacts was identified. The coronary artery segments were visually evaluated to investigate their assessability. In 46 (76.7 %) patients, the optimal reconstruction phase was end-diastole, whereas in 6 (10.0 %) patients it was end-systole or mid-diastole, and in 2 (3.3 %) patients it was another cardiac phase. In 53 (88.3 %) of the controls, the optimal reconstruction phase was mid-diastole, whereas it was end-systole in 4 (6.7 %), and in 3 (5.0 %) it was another cardiac phase. There was a significant difference between patients with AF and the controls in the optimal phase (p < 0.01) but not in the visual image quality score (p = 0.06). The optimal reconstruction phase in most patients with AF was the end-diastolic phase. The end-systolic phase tended to be optimal in AF patients with higher average heart rates. (orig.)

  8. Motion tracking-enhanced MART for tomographic PIV

    International Nuclear Information System (INIS)

    Novara, Matteo; Scarano, Fulvio; Batenburg, Kees Joost

    2010-01-01

    A novel technique to increase the accuracy of multiplicative algebraic reconstruction technique (MART) reconstruction from tomographic particle image velocimetry (PIV) recordings at higher seeding density than currently possible is presented. The motion tracking enhancement (MTE) method is based on the combined utilization of images from two or more exposures to enhance the reconstruction of individual intensity fields. The working principle is first introduced qualitatively, and the mathematical background is given that explains how the MART reconstruction can be improved on the basis of an improved first guess object obtained from the combination of non-simultaneous views reduced to the same time instant deforming the 3D objects by an estimate of the particle motion field. The performances of MTE are quantitatively evaluated by numerical simulation of the imaging, reconstruction and image correlation processes. The cases of two or more exposures obtained from time-resolved experiments are considered. The iterative application of MTE appears to significantly improve the reconstruction quality, first by decreasing the intensity of the ghost images and second, by increasing the intensity and the reconstruction precision for the actual particles. Based on computer simulations, the maximum imaged seeding density that can be dealt with is tripled with respect to the MART analysis applied to a single exposure. The analysis also illustrates that the maximum effect of the MTE method is comparable to that of doubling the number of cameras in the tomographic system. Experiments performed on a transitional jet at Re = 5000 apply the MTE method to double-frame recordings. The velocity measurement precision is increased for a system with fewer views (two or three cameras compared with four cameras). The ghost particles' intensity is also visibly reduced although to a lesser extent with respect to the computer simulations. The velocity and vorticity field obtained from a three

  9. Planning, guidance, and quality assurance of pelvic screw placement using deformable image registration

    Science.gov (United States)

    Goerres, J.; Uneri, A.; Jacobson, M.; Ramsay, B.; De Silva, T.; Ketcha, M.; Han, R.; Manbachi, A.; Vogt, S.; Kleinszig, G.; Wolinsky, J.-P.; Osgood, G.; Siewerdsen, J. H.

    2017-12-01

    Percutaneous pelvic screw placement is challenging due to narrow bone corridors surrounded by vulnerable structures and difficult visual interpretation of complex anatomical shapes in 2D x-ray projection images. To address these challenges, a system for planning, guidance, and quality assurance (QA) is presented, providing functionality analogous to surgical navigation, but based on robust 3D-2D image registration techniques using fluoroscopy images already acquired in routine workflow. Two novel aspects of the system are investigated: automatic planning of pelvic screw trajectories and the ability to account for deformation of surgical devices (K-wire deflection). Atlas-based registration is used to calculate a patient-specific plan of screw trajectories in preoperative CT. 3D-2D registration aligns the patient to CT within the projective geometry of intraoperative fluoroscopy. Deformable known-component registration (dKC-Reg) localizes the surgical device, and the combination of plan and device location is used to provide guidance and QA. A leave-one-out analysis evaluated the accuracy of automatic planning, and a cadaver experiment compared the accuracy of dKC-Reg to rigid approaches (e.g. optical tracking). Surgical plans conformed within the bone cortex by 3-4 mm for the narrowest corridor (superior pubic ramus) and  >5 mm for the widest corridor (tear drop). The dKC-Reg algorithm localized the K-wire tip within 1.1 mm and 1.4° and was consistently more accurate than rigid-body tracking (errors up to 9 mm). The system was shown to automatically compute reliable screw trajectories and accurately localize deformed surgical devices (K-wires). Such capability could improve guidance and QA in orthopaedic surgery, where workflow is impeded by manual planning, conventional tool trackers add complexity and cost, rigid tool assumptions are often inaccurate, and qualitative interpretation of complex anatomy from 2D projections is prone to trial

  10. Tomographic bremsstrahlung imaging with yttrium-90 in the context of radioembolisation of liver tumors; Tomografische Bildgebung mit Yttrium-90-Bremsstrahlung im Rahmen der Radioembolisation von Lebertumoren

    Energy Technology Data Exchange (ETDEWEB)

    Grosser, Oliver Stephan

    2013-04-12

    Establish tomographic Bremsstrahlung SPECT imaging (BSPECT) for the clinical validation of Selective Internal Radiotherapy (SIRT) with Yttrium-90 ({sup 90}Y) labelled microspheres. Various energy ranges (75 ± 3.8 keV; 135 ± 6.8 keV; 167 ± 8.4 keV) and the summation window were studied to see if they were suitable for BSPECT. To this end, clinically available reconstruction techniques were analysed for their suitability for BSPECT. The tomographic examinations were performed on a cylindrical phantom filled with spheres of different diameters d = [28; 35; 40; 50; 60] mm in a non-active waterfilled background. The spheres were filled with identical {sup 90}Y activity concentration (AC). Measurements were conducted at AC = [14.58; 5.20; 1.98; 0.66] MBq/cm{sup 3}. The BSPECT were reconstructed with filtered back-projection (FBP), a 2D Ordered-Subset Expectation Maximisation Algorithm (2D-OSEM) and a 3D Geometric Mean Algorithm (3D-GMA). Evaluation was made visually and on the basis of objective performance parameters such as contrast, signal-to-noise ratio (SNR) and image noise. While the 75 keV ± 3.8 keV window was identified as suitable for the BSPECT, limitations were revealed as to use of different implementations of the Point Spread Function (PSF). It was found for all reconstruction techniques that, at a given sphere diameter, there existed a linear relationship between the AC in the spheres and the reconstructed pulse rate per volume element. The recovery effect was verified for small spheres. The iterative techniques were found to be suitable for the BSPECT at all AC. At low AC, the 3D-GMA exhibited the least noise and the highest SNR. The FBP turned out to be entirely inappropriate for the BSPECT. The narrow energy window in which the bremsstrahlung interferes with the characteristic X-radiation of lead can be used for BSPECT. In this approach, the tomographic data reconstructed with different algorithms exhibited a varying image quality, with the iterative

  11. Estimation of the Above Ground Biomass of Tropical Forests using Polarimetric and Tomographic SAR Data Acquired at P Band and 3-D Imaging Techniques

    Science.gov (United States)

    Ferro-Famil, L.; El Hajj Chehade, B.; Ho Tong Minh, D.; Tebaldini, S.; LE Toan, T.

    2016-12-01

    Developing and improving methods to monitor forest biomass in space and time is a timely challenge, especially for tropical forests, for which SAR imaging at larger wavelength presents an interesting potential. Nevertheless, directly estimating tropical forest biomass from classical 2-D SAR images may reveal a very complex and ill-conditioned problem, since a SAR echo is composed of numerous contributions, whose features and importance depend on many geophysical parameters, such has ground humidity, roughness, topography… that are not related to biomass. Recent studies showed that SAR modes of diversity, i.e. polarimetric intensity ratios or interferometric phase centers, do not fully resolve this under-determined problem, whereas Pol-InSAR tree height estimates may be related to biomass through allometric relationships, with, in general over tropical forests, significant levels of uncertainty and lack of robustness. In this context, 3-D imaging using SAR tomography represents an appealing solution at larger wavelengths, for which wave penetration properties ensures a high quality mapping of a tropical forest reflectivity in the vertical direction. This paper presents a series of studies led, in the frame of the preparation of the next ESA mission BIOMASS, on the estimation of biomass over a tropical forest in French Guiana, using Polarimetric SAR Tomographic (Pol-TomSAR) data acquired at P band by ONERA. It is then shown that Pol-TomoSAR significantly improves the retrieval of forest above ground biomass (AGB) in a high biomass forest (200 up to 500 t/ha), with an error of only 10% at 1.5-ha resolution using a reflectivity estimates sampled at a predetermined elevation. The robustness of this technique is tested by applying the same approach over another site, and results show a similar relationship between AGB and tomographic reflectivity over both sites. The excellent ability of Pol-TomSAR to retrieve both canopy top heights and ground topography with an error

  12. SU-E-P-41: Imaging Coordination of Cone Beam CT, On-Board Image Conjunction with Optical Image Guidance for SBRT Treatment with Respiratory Motion Management

    International Nuclear Information System (INIS)

    Liu, Y; Campbell, J

    2015-01-01

    Purpose: To spare normal tissue for SBRT lung/liver patients, especially for patients with significant tumor motion, image guided respiratory motion management has been widely implemented in clinical practice. The purpose of this study was to evaluate imaging coordination of cone beam CT, on-board X-ray image conjunction with optical image guidance for SBRT treatment with motion management. Methods: Currently in our clinic a Varian Novlis Tx was utilized for treating SBRT patients implementing CBCT. A BrainLAB X-ray ExacTrac imaging system in conjunction with optical guidance was primarily used for SRS patients. CBCT and X-ray imaging system were independently calibrated with 1.0 mm tolerance. For SBRT lung/liver patients, the magnitude of tumor motion was measured based-on 4DCT and the measurement was analyzed to determine if patients would be beneficial with respiratory motion management. For patients eligible for motion management, an additional CT with breath holding would be scanned and used as primary planning CT and as reference images for Cone beam CT. During the SBRT treatment, a CBCT with pause and continuing technology would be performed with patients holding breath, which may require 3–4 partially scanned CBCT to combine as a whole CBCT depending on how long patients capable of holding breath. After patients being setup by CBCT images, the ExactTrac X-ray imaging system was implemented with patients’ on-board X-ray images compared to breath holding CT-based DRR. Results: For breath holding patients SBRT treatment, after initially localizing patients with CBCT, we then position patients with ExacTrac X-ray and optical imaging system. The observed deviations of real-time optical guided position average at 3.0, 2.5 and 1.5 mm in longitudinal, vertical and lateral respectively based on 35 treatments. Conclusion: The respiratory motion management clinical practice improved our physician confidence level to give tighter tumor margin for sparing normal

  13. Cone beam computed tomographic imaging: perspective, challenges, and the impact of near-trend future applications.

    Science.gov (United States)

    Cavalcanti, Marcelo Gusmão Paraiso

    2012-01-01

    Cone beam computed tomography (CBCT) can be considered as a valuable imaging modality for improving diagnosis and treatment planning to achieve true guidance for several craniofacial surgical interventions. A new concept and perspective in medical informatics is the highlight discussion about the new imaging interactive workflow. The aim of this article was to present, in a short literature review, the usefulness of CBCT technology as an important alternative imaging modality, highlighting current practices and near-term future applications in cutting-edge thought-provoking perspectives for craniofacial surgical assessment. This article explains the state of the art of CBCT improvements, medical workstation, and perspectives of the dedicated unique hardware and software, which can be used from the CBCT source. In conclusion, CBCT technology is developing rapidly, and many advances are on the horizon. Further progress in medical workstations, engineering capabilities, and improvement in independent software-some open source-should be attempted with this new imaging method. The perspectives, challenges, and pitfalls in CBCT will be delineated and evaluated along with the technological developments.

  14. Rapid tomographic reconstruction based on machine learning for time-resolved combustion diagnostics

    Science.gov (United States)

    Yu, Tao; Cai, Weiwei; Liu, Yingzheng

    2018-04-01

    Optical tomography has attracted surged research efforts recently due to the progress in both the imaging concepts and the sensor and laser technologies. The high spatial and temporal resolutions achievable by these methods provide unprecedented opportunity for diagnosis of complicated turbulent combustion. However, due to the high data throughput and the inefficiency of the prevailing iterative methods, the tomographic reconstructions which are typically conducted off-line are computationally formidable. In this work, we propose an efficient inversion method based on a machine learning algorithm, which can extract useful information from the previous reconstructions and build efficient neural networks to serve as a surrogate model to rapidly predict the reconstructions. Extreme learning machine is cited here as an example for demonstrative purpose simply due to its ease of implementation, fast learning speed, and good generalization performance. Extensive numerical studies were performed, and the results show that the new method can dramatically reduce the computational time compared with the classical iterative methods. This technique is expected to be an alternative to existing methods when sufficient training data are available. Although this work is discussed under the context of tomographic absorption spectroscopy, we expect it to be useful also to other high speed tomographic modalities such as volumetric laser-induced fluorescence and tomographic laser-induced incandescence which have been demonstrated for combustion diagnostics.

  15. Influence of arm positioning on tomographic thallium-201 myocardial perfusion imaging and the effect of attenuation correction

    International Nuclear Information System (INIS)

    Prvulovich, E.M.; Jarritt, P.H.; Vorontsova, E.; Bomanji, J.B.; Ell, P.J.

    2000-01-01

    Lateral attenuation in single-photon emission tomography (SPET) myocardial perfusion imaging (MPI) has been attributed to the left arm if it is held by the patient's side during data acquisition. As a result MPI data are conventionally acquired with the arms held above the head. The aims of this study were to determine the effect of imaging arms down on reconstructed tomographic images depicting regional myocardial thallium-201 distribution and to assess whether attenuation-corrected (AC) myocardial perfusion images acquired arms down could replace uncorrected (NC) images acquired arms up for routine clinical service. Twenty-eight patients referred for routine MPI underwent sequential 180 emission/transmission imaging for attenuation correction using an L-shaped dual-headed gamma camera (GE Optima) fitted with two gadolinium-153 scanning line sources. Delay data were acquired twice: once supine with the arms up and then supine with the arms down. Detector radius of rotation (ROR) for arms up and arms-down studies was recorded. For each data set, count density was measured in 17 segments of a polar plot and segmental uptake expressed relative to study maximum. Oblique images were assessed qualitatively by two observers blinded to study type for tracer distribution and overall quality. Transmission maps were assessed for truncation. Mean detector ROR was 190 mm for arms-up studies and 232 mm for arms-down studies (P 201 Tl distribution, particularly anterolaterally. There is lateral undercorrection in approximately 10% of AC arms-down studies, possibly because of attenuation map truncation. Image quality is reduced in about one-third of AC arms-down studies compared with NC arms-up studies. These data suggest that this attenuation correction method is not sufficiently robust to allow routine acquisition of MPI data with the arms down. (orig.)

  16. The use of transport and diffusion equations in the three-dimensional reconstruction of computerized tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Sandrerley Ramos, E-mail: sandrerley@eee.ufg.br [Escola de Engenharia Eletrica e de Computacao - EEEC, Universidade Federal de Goias - UFG, Goiania, GO (Brazil); Flores, Edna Lucia; Pires, Dulcineia Goncalves F.; Carrijo, Gilberto Arantes; Veiga, Antonio Claudio Paschoarelli [Faculdade de Engenharia Eletrica - FEELT, Universidade Federal de Uberlandia - UFU, Uberlandia, MG (Brazil); Barcelos, Celia Aparecida Z. [Faculdade de Matematica, Universidade Federal de Uberlandia - UFU, Uberlandia, MG (Brazil)

    2012-09-15

    The visualization of a computerized tomographic (TC) exam in 3D increases the quality of the medical diagnosis and, consequently, the success probability in the treatment. To obtain a high quality image it is necessary to obtain slices which are close to one another. Motivated towards the goal of reaching an improved balance between quantity of slices and visualization quality, this research work presents a digital inpainting technique of 3D interpolation for CT slices used in the visualization of human body structures. The inpainting is carried out via non-linear partial differential equations (PDE). The PDE's have been used, in the image-processing context to fill in the damaged regions in a digital 2D image. Inspired by this idea, this article proposes an interpolation method for the filling in of the empty regions between the CT slices. To do it, considering the high similarity between two consecutive real slice, the first step of the proposed method is to create the virtual slices. The virtual slices contain all similarity between the intercalated slices and, when there are not similarities between real slices, the virtual slices will contain indefinite portions. In the second step of the proposed method, the created virtual slices will be used together with the real slices images, in the reconstruction of the structure in three dimensions, mapped onto the exam. The proposed method is capable of reconstructing the curvatures of the patient's internal structures without using slices that are close to one another. The experiments carried out show the proposed method's efficiency. (author)

  17. SU-G-BRA-03: PCA Based Imaging Angle Optimization for 2D Cine MRI Based Radiotherapy Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T; Yue, N; Jabbour, S; Zhang, M [Rutgers University, New Brunswick, NJ (United States)

    2016-06-15

    Purpose: To develop an imaging angle optimization methodology for orthogonal 2D cine MRI based radiotherapy guidance using Principal Component Analysis (PCA) of target motion retrieved from 4DCT. Methods: We retrospectively analyzed 4DCT of 6 patients with lung tumor. A radiation oncologist manually contoured the target volume at the maximal inhalation phase of the respiratory cycle. An object constrained deformable image registration (DIR) method has been developed to track the target motion along the respiration at ten phases. The motion of the center of the target mass has been analyzed using the PCA to find out the principal motion components that were uncorrelated with each other. Two orthogonal image planes for cineMRI have been determined using this method to minimize the through plane motion during MRI based radiotherapy guidance. Results: 3D target respiratory motion for all 6 patients has been efficiently retrieved from 4DCT. In this process, the object constrained DIR demonstrated satisfactory accuracy and efficiency to enable the automatic motion tracking for clinical application. The average motion amplitude in the AP, lateral, and longitudinal directions were 3.6mm (min: 1.6mm, max: 5.6mm), 1.7mm (min: 0.6mm, max: 2.7mm), and 5.6mm (min: 1.8mm, max: 16.1mm), respectively. Based on PCA, the optimal orthogonal imaging planes were determined for cineMRI. The average angular difference between the PCA determined imaging planes and the traditional AP and lateral imaging planes were 47 and 31 degrees, respectively. After optimization, the average amplitude of through plane motion reduced from 3.6mm in AP images to 2.5mm (min:1.3mm, max:3.9mm); and from 1.7mm in lateral images to 0.6mm (min: 0.2mm, max:1.5mm), while the principal in plane motion amplitude increased from 5.6mm to 6.5mm (min: 2.8mm, max: 17mm). Conclusion: DIR and PCA can be used to optimize the orthogonal image planes of cineMRI to minimize the through plane motion during radiotherapy

  18. SU-G-BRA-03: PCA Based Imaging Angle Optimization for 2D Cine MRI Based Radiotherapy Guidance

    International Nuclear Information System (INIS)

    Chen, T; Yue, N; Jabbour, S; Zhang, M

    2016-01-01

    Purpose: To develop an imaging angle optimization methodology for orthogonal 2D cine MRI based radiotherapy guidance using Principal Component Analysis (PCA) of target motion retrieved from 4DCT. Methods: We retrospectively analyzed 4DCT of 6 patients with lung tumor. A radiation oncologist manually contoured the target volume at the maximal inhalation phase of the respiratory cycle. An object constrained deformable image registration (DIR) method has been developed to track the target motion along the respiration at ten phases. The motion of the center of the target mass has been analyzed using the PCA to find out the principal motion components that were uncorrelated with each other. Two orthogonal image planes for cineMRI have been determined using this method to minimize the through plane motion during MRI based radiotherapy guidance. Results: 3D target respiratory motion for all 6 patients has been efficiently retrieved from 4DCT. In this process, the object constrained DIR demonstrated satisfactory accuracy and efficiency to enable the automatic motion tracking for clinical application. The average motion amplitude in the AP, lateral, and longitudinal directions were 3.6mm (min: 1.6mm, max: 5.6mm), 1.7mm (min: 0.6mm, max: 2.7mm), and 5.6mm (min: 1.8mm, max: 16.1mm), respectively. Based on PCA, the optimal orthogonal imaging planes were determined for cineMRI. The average angular difference between the PCA determined imaging planes and the traditional AP and lateral imaging planes were 47 and 31 degrees, respectively. After optimization, the average amplitude of through plane motion reduced from 3.6mm in AP images to 2.5mm (min:1.3mm, max:3.9mm); and from 1.7mm in lateral images to 0.6mm (min: 0.2mm, max:1.5mm), while the principal in plane motion amplitude increased from 5.6mm to 6.5mm (min: 2.8mm, max: 17mm). Conclusion: DIR and PCA can be used to optimize the orthogonal image planes of cineMRI to minimize the through plane motion during radiotherapy

  19. EPA guidance on improving the image of psychiatry.

    Science.gov (United States)

    Möller-Leimkühler, A M; Möller, H-J; Maier, W; Gaebel, W; Falkai, P

    2016-03-01

    This paper explores causes, explanations and consequences of the negative image of psychiatry and develops recommendations for improvement. It is primarily based on a WPA guidance paper on how to combat the stigmatization of psychiatry and psychiatrists and a Medline search on related publications since 2010. Furthermore, focussing on potential causes and explanations, the authors performed a selective literature search regarding additional image-related issues such as mental health literacy and diagnostic and treatment issues. Underestimation of psychiatry results from both unjustified prejudices of the general public, mass media and healthcare professionals and psychiatry's own unfavourable coping with external and internal concerns. Issues related to unjustified devaluation of psychiatry include overestimation of coercion, associative stigma, lack of public knowledge, need to simplify complex mental issues, problem of the continuum between normality and psychopathology, competition with medical and non-medical disciplines and psychopharmacological treatment. Issues related to psychiatry's own contribution to being underestimated include lack of a clear professional identity, lack of biomarkers supporting clinical diagnoses, limited consensus about best treatment options, lack of collaboration with other medical disciplines and low recruitment rates among medical students. Recommendations are proposed for creating and representing a positive self-concept with different components. The negative image of psychiatry is not only due to unfavourable communication with the media, but is basically a problem of self-conceptualization. Much can be improved. However, psychiatry will remain a profession with an exceptional position among the medical disciplines, which should be seen as its specific strength.

  20. Tomographic PIV behind a prosthetic heart valve

    Science.gov (United States)

    Hasler, D.; Landolt, A.; Obrist, D.

    2016-05-01

    The instantaneous three-dimensional velocity field past a bioprosthetic heart valve was measured using tomographic particle image velocimetry. Two digital cameras were used together with a mirror setup to record PIV images from four different angles. Measurements were conducted in a transparent silicone phantom with a simplified geometry of the aortic root. The refraction indices of the silicone phantom and the working fluid were matched to minimize optical distortion from the flow field to the cameras. The silicone phantom of the aorta was integrated in a flow loop driven by a piston pump. Measurements were conducted for steady and pulsatile flow conditions. Results of the instantaneous, ensemble and phase-averaged flow field are presented. The three-dimensional velocity field reveals a flow topology, which can be related to features of the aortic valve prosthesis.

  1. Added Value of Contrast-Enhanced Ultrasound on Biopsies of Focal Hepatic Lesions Invisible on Fusion Imaging Guidance.

    Science.gov (United States)

    Kang, Tae Wook; Lee, Min Woo; Song, Kyoung Doo; Kim, Mimi; Kim, Seung Soo; Kim, Seong Hyun; Ha, Sang Yun

    2017-01-01

    To assess whether contrast-enhanced ultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making. The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed. Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5-1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p making for 11 of 16 patients (68.8%). The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making.

  2. Line-scanning tomographic optical microscope with isotropic transfer function

    International Nuclear Information System (INIS)

    Gajdátsy, Gábor; Dudás, László; Erdélyi, Miklós; Szabó, Gábor

    2010-01-01

    An imaging method and optical system, referred to as a line-scanning tomographic optical microscope (LSTOM) using a combination of line-scanning technique and CT reconstruction principle, is proposed and studied theoretically and experimentally. In our implementation a narrow focus line is scanned over the sample and the reflected light is measured in a confocal arrangement. One such scan is equivalent to a transverse projection in tomography. Repeating the scanning procedure in several directions, a number of transverse projections are recorded from which the image can be obtained using conventional CT reconstruction algorithms. The resolution of the image is independent of the spatial dimensions and structure of the applied detector; furthermore, the transfer function of the system is isotropic. The imaging performance of the implemented confocal LSTOM was compared with a point-scanning confocal microscope, based on recorded images. These images demonstrate that the resolution of the confocal LSTOM exceeds (by 15%) the resolution limit of a point-scanning confocal microscope

  3. Imaging properties of a positron tomograph with 280 BGO crystals

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Budinger, T.F.; Huesman, R.H.; Cahoon, J.L.; Vuletich, T.

    1980-11-01

    The basic imaging properties of the Donner 280-BGO-Crystal positron tomograph were measured and compared with the same system when it was equipped with 280 NaI(T1) crystals. The NaI(T1) crystals were 8 mm x 30 mm x 50 mm deep, sealed in 10 mm wide stainless steel cans. The BGO crystals are 9.5 mm x 32 mm x 32 mm deep and as they are not hygroscopic do not require sealed cans. With a shielding gap of 3 cm (section thickness 1.7 cm FWHM) the sensitivity of the BGO system is 55,000 events per sec for 1 μCi per cm 3 in a 20 cm cylinder of water, which is 2.3 times higher than the NaI(T1) system. For a 200 μCi/cm line source on the ring axis in a 20 cm diameter water cylinder, the BGO system records 86% of the scatter fraction and 66% of the accidental fraction of the NaI(T1) system. The lower light yield and poorer time resolution of BGO requires a wider coincidence timing window than NaI(T1). However, the ability to use full-energy pulse height selection with a 2.3-fold improvement in sensitivity results in an overall reduction in the fraction of accidental events recorded. The in-plane resolution of the BGO system is 9 to 10 mm FWHM within the central 30 cm diameter field, and the radial elongation at the edge of the field in the NaI(T1) system has been nearly eliminated

  4. Visual hull method for tomographic PIV measurement of flow around moving objects

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, D.; Longmire, E.K. [University of Minnesota, Department of Aerospace Engineering and Mechanics, Minneapolis, MN (United States)

    2012-10-15

    Tomographic particle image velocimetry (PIV) is a recently developed method to measure three components of velocity within a volumetric space. We present a visual hull technique that automates identification and masking of discrete objects within the measurement volume, and we apply existing tomographic PIV reconstruction software to measure the velocity surrounding the objects. The technique is demonstrated by considering flow around falling bodies of different shape with Reynolds number {proportional_to}1,000. Acquired image sets are processed using separate routines to reconstruct both the volumetric mask around the object and the surrounding tracer particles. After particle reconstruction, the reconstructed object mask is used to remove any ghost particles that otherwise appear within the object volume. Velocity vectors corresponding with fluid motion can then be determined up to the boundary of the visual hull without being contaminated or affected by the neighboring object velocity. Although the visual hull method is not meant for precise tracking of objects, the reconstructed object volumes nevertheless can be used to estimate the object location and orientation at each time step. (orig.)

  5. TH-CD-207A-08: Simulated Real-Time Image Guidance for Lung SBRT Patients Using Scatter Imaging

    International Nuclear Information System (INIS)

    Redler, G; Cifter, G; Templeton, A; Lee, C; Bernard, D; Liao, Y; Zhen, H; Turian, J; Chu, J

    2016-01-01

    Purpose: To develop a comprehensive Monte Carlo-based model for the acquisition of scatter images of patient anatomy in real-time, during lung SBRT treatment. Methods: During SBRT treatment, images of patient anatomy can be acquired from scattered radiation. To rigorously examine the utility of scatter images for image guidance, a model is developed using MCNP code to simulate scatter images of phantoms and lung cancer patients. The model is validated by comparing experimental and simulated images of phantoms of different complexity. The differentiation between tissue types is investigated by imaging objects of known compositions (water, lung, and bone equivalent). A lung tumor phantom, simulating materials and geometry encountered during lung SBRT treatments, is used to investigate image noise properties for various quantities of delivered radiation (monitor units(MU)). Patient scatter images are simulated using the validated simulation model. 4DCT patient data is converted to an MCNP input geometry accounting for different tissue composition and densities. Lung tumor phantom images acquired with decreasing imaging time (decreasing MU) are used to model the expected noise amplitude in patient scatter images, producing realistic simulated patient scatter images with varying temporal resolution. Results: Image intensity in simulated and experimental scatter images of tissue equivalent objects (water, lung, bone) match within the uncertainty (∼3%). Lung tumor phantom images agree as well. Specifically, tumor-to-lung contrast matches within the uncertainty. The addition of random noise approximating quantum noise in experimental images to simulated patient images shows that scatter images of lung tumors can provide images in as fast as 0.5 seconds with CNR∼2.7. Conclusions: A scatter imaging simulation model is developed and validated using experimental phantom scatter images. Following validation, lung cancer patient scatter images are simulated. These simulated

  6. TH-CD-207A-08: Simulated Real-Time Image Guidance for Lung SBRT Patients Using Scatter Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Redler, G; Cifter, G; Templeton, A; Lee, C; Bernard, D; Liao, Y; Zhen, H; Turian, J; Chu, J [Rush University Medical Center, Chicago, IL (United States)

    2016-06-15

    Purpose: To develop a comprehensive Monte Carlo-based model for the acquisition of scatter images of patient anatomy in real-time, during lung SBRT treatment. Methods: During SBRT treatment, images of patient anatomy can be acquired from scattered radiation. To rigorously examine the utility of scatter images for image guidance, a model is developed using MCNP code to simulate scatter images of phantoms and lung cancer patients. The model is validated by comparing experimental and simulated images of phantoms of different complexity. The differentiation between tissue types is investigated by imaging objects of known compositions (water, lung, and bone equivalent). A lung tumor phantom, simulating materials and geometry encountered during lung SBRT treatments, is used to investigate image noise properties for various quantities of delivered radiation (monitor units(MU)). Patient scatter images are simulated using the validated simulation model. 4DCT patient data is converted to an MCNP input geometry accounting for different tissue composition and densities. Lung tumor phantom images acquired with decreasing imaging time (decreasing MU) are used to model the expected noise amplitude in patient scatter images, producing realistic simulated patient scatter images with varying temporal resolution. Results: Image intensity in simulated and experimental scatter images of tissue equivalent objects (water, lung, bone) match within the uncertainty (∼3%). Lung tumor phantom images agree as well. Specifically, tumor-to-lung contrast matches within the uncertainty. The addition of random noise approximating quantum noise in experimental images to simulated patient images shows that scatter images of lung tumors can provide images in as fast as 0.5 seconds with CNR∼2.7. Conclusions: A scatter imaging simulation model is developed and validated using experimental phantom scatter images. Following validation, lung cancer patient scatter images are simulated. These simulated

  7. Effective segmentation of fresh post-mortem murine lung parenchyma in phase contrast X-ray tomographic microscopy images

    International Nuclear Information System (INIS)

    Oikonomidis, Ioannis Vogiatzis; Cremona, Tiziana P; Schittny, Johannes C; Lovric, Goran; Arcadu, Filippo; Stampanoni, Marco

    2017-01-01

    The acinus represents the functional unit of the mammalian lung. It is defined as the small tree of gas-exchanging airways, which is fed by the most distal purely conducting airway. Different hypotheses exist on how the fine structure of the acinus changes during ventilation and development. Since in classical 2-dimensional (2D) sections of the lung the borders of the acini are not detectable, every study of acini requires 3-dimensional (3D) datasets. As a basis for further studies of pulmonary acini we imaged rodent lungs as close to life as possible using phase contrast synchrotron radiation-based X-ray tomographic microscopy (SRXTM), and developed a protocol for the segmentation of the alveolar septa. The method is based on a combined multilevel filtering approach. Seeds are automatically defined for separate regions of tissue and airspace during each 2D filtering level and then given as input to a 3D random walk segmentation. Thus, the different types of artifacts present in the images are treated separately, taking into account the sample’s structural complexity. The proposed procedure yields high-quality 3D segmentations of acinar microstructure that can be used for a reliable morphological analysis. (paper)

  8. Respiration-correlated image guidance is the most important radiotherapy motion management strategy for most lung cancer patients

    DEFF Research Database (Denmark)

    Korreman, Stine; Persson, Gitte; Nygaard, Ditte Eklund

    2012-01-01

    The purpose of this study was to quantify the effects of four-dimensional computed tomography (4DCT), 4D image guidance (4D-IG), and beam gating on calculated treatment field margins in a lung cancer patient population....

  9. A fast multi-resolution approach to tomographic PIV

    Science.gov (United States)

    Discetti, Stefano; Astarita, Tommaso

    2012-03-01

    Tomographic particle image velocimetry (Tomo-PIV) is a recently developed three-component, three-dimensional anemometric non-intrusive measurement technique, based on an optical tomographic reconstruction applied to simultaneously recorded images of the distribution of light intensity scattered by seeding particles immersed into the flow. Nowadays, the reconstruction process is carried out mainly by iterative algebraic reconstruction techniques, well suited to handle the problem of limited number of views, but computationally intensive and memory demanding. The adoption of the multiplicative algebraic reconstruction technique (MART) has become more and more accepted. In the present work, a novel multi-resolution approach is proposed, relying on the adoption of a coarser grid in the first step of the reconstruction to obtain a fast estimation of a reliable and accurate first guess. A performance assessment, carried out on three-dimensional computer-generated distributions of particles, shows a substantial acceleration of the reconstruction process for all the tested seeding densities with respect to the standard method based on 5 MART iterations; a relevant reduction in the memory storage is also achieved. Furthermore, a slight accuracy improvement is noticed. A modified version, improved by a multiplicative line of sight estimation of the first guess on the compressed configuration, is also tested, exhibiting a further remarkable decrease in both memory storage and computational effort, mostly at the lowest tested seeding densities, while retaining the same performances in terms of accuracy.

  10. Respiration-Correlated Image Guidance Is the Most Important Radiotherapy Motion Management Strategy for Most Lung Cancer Patients

    International Nuclear Information System (INIS)

    Korreman, Stine; Persson, Gitte; Nygaard, Ditte; Brink, Carsten; Juhler-Nøttrup, Trine

    2012-01-01

    Purpose: The purpose of this study was to quantify the effects of four-dimensional computed tomography (4DCT), 4D image guidance (4D-IG), and beam gating on calculated treatment field margins in a lung cancer patient population. Materials and Methods: Images were acquired from 46 lung cancer patients participating in four separate protocols at three institutions in Europe and the United States. Seven patients were imaged using fluoroscopy, and 39 patients were imaged using 4DCT. The magnitude of respiratory tumor motion was measured. The required treatment field margins were calculated using a statistical recipe (van Herk M, et al. Int J Radiat Oncol Biol Phys 2000;474:1121–1135), with magnitudes of all uncertainties, except respiratory peak-to-peak displacement, the same for all patients, taken from literature. Required margins for respiratory motion management were calculated using the residual respiratory tumor motion for each patient for various motion management strategies. Margin reductions for respiration management were calculated using 4DCT, 4D-IG, and gated beam delivery. Results: The median tumor motion magnitude was 4.4 mm for the 46 patients (range 0–29.3 mm). This value corresponded to required treatment field margins of 13.7 to 36.3 mm (median 14.4 mm). The use of 4DCT, 4D-IG, and beam gating required margins that were reduced by 0 to 13.9 mm (median 0.5 mm), 3 to 5.2 mm (median 5.1 mm), and 0 to 7 mm (median 0.2 mm), respectively, to a total of 8.5 to 12.4 mm (median 8.6 mm). Conclusion: A respiratory management strategy for lung cancer radiotherapy including planning on 4DCT scans and daily image guidance provides a potential reduction of 37% to 47% in treatment field margins. The 4D image guidance strategy was the most effective strategy for >85% of the patients.

  11. Feasibility of photon-counting K-edge imaging in X-ray and computed tomographic systems: Monte Carlo simulation studies

    International Nuclear Information System (INIS)

    Lee, Seung-Wan; Choi, Yu-Na; Cho, Hyo-Min; Lee, Young-Jin; Ryu, Hyun-Ju; Kim, Hee-Joung

    2011-01-01

    Conventional X-ray systems and X-ray computed tomography (CT) systems, which use detectors operated in the integrating mode, are not able to reflect spectral information because the detector output is proportional to the energy fluence integrated over the whole spectrum. Photon-counting detectors have been considered as alternative devices. These detectors can measure the photon energy deposited by each event and improve the image quality. In this study, we investigated the feasibility of K-edge imaging using a photon-counting detector and evaluated the capability of material decomposition in X-ray images. The geometries of X-ray imaging systems equipped with cadmium telluride (CdTe) detectors and phantoms consisting of different materials were designed using Geant4 Application for Tomographic Emission (GATE) version 6.0. To observe the effect of a discontinuity in the attenuation due to the K-edge of a high atomic number material, we chose the energy windows to be one below and one above the K-edge absorption energy of the target material. The contrast-to-noise ratios (CNRs) of the target materials were increased at selective energy levels above the K-edge absorption energy because the attenuation is more dramatically increased at energies above the K-edge absorption energy of the material than at energies below that. The CNRs for the target materials in the K-edge image were proportional to the material concentration. The results of this study show that K-edge imaging can be carried out in conventional X-ray systems and X-ray CT systems using CdTe photon-counting detectors and that the target materials can be separated from background materials by using K-edge imaging. The photon-counting detector has potential to provide improved image quality, and this study will be used as a basis for future studies on photon-counting X-ray imaging.

  12. Constraining fault interpretation through tomographic velocity gradients: application to northern Cascadia

    Directory of Open Access Journals (Sweden)

    K. Ramachandran

    2012-02-01

    Full Text Available Spatial gradients of tomographic velocities are seldom used in interpretation of subsurface fault structures. This study shows that spatial velocity gradients can be used effectively in identifying subsurface discontinuities in the horizontal and vertical directions. Three-dimensional velocity models constructed through tomographic inversion of active source and/or earthquake traveltime data are generally built from an initial 1-D velocity model that varies only with depth. Regularized tomographic inversion algorithms impose constraints on the roughness of the model that help to stabilize the inversion process. Final velocity models obtained from regularized tomographic inversions have smooth three-dimensional structures that are required by the data. Final velocity models are usually analyzed and interpreted either as a perturbation velocity model or as an absolute velocity model. Compared to perturbation velocity model, absolute velocity models have an advantage of providing constraints on lithology. Both velocity models lack the ability to provide sharp constraints on subsurface faults. An interpretational approach utilizing spatial velocity gradients applied to northern Cascadia shows that subsurface faults that are not clearly interpretable from velocity model plots can be identified by sharp contrasts in velocity gradient plots. This interpretation resulted in inferring the locations of the Tacoma, Seattle, Southern Whidbey Island, and Darrington Devil's Mountain faults much more clearly. The Coast Range Boundary fault, previously hypothesized on the basis of sedimentological and tectonic observations, is inferred clearly from the gradient plots. Many of the fault locations imaged from gradient data correlate with earthquake hypocenters, indicating their seismogenic nature.

  13. Methodological study of radionuclide tomographic phase analysis in localization of accessory conduction pathway in patients with wolff-parkinson-white syndrome

    International Nuclear Information System (INIS)

    Wo Jinshan; Zhu Junren; Li Zhishan

    1994-01-01

    In this study, the methodology of tomographic phase analysis to detect the site of accessory conduction pathway (ACP) in patients with Wolff-Parkinson-White syndrome was presented. We analyzed the major factors that affect image reconstruction, selection of tomographic planes and phase analysis, also discussed the key step for reconstruction short-axial section that parallel and closest to the level of atrio-ventricular rings. Of five patients undergoing this procedure prior to surgery, tomographic phase analysis correctly identified the site of ACP confirmed by epicardial mapping in all of the five patients. Our results suggest this approach to be an objective, clear and correct one for localizing ACP

  14. Distance weighting for improved tomographic reconstructions

    International Nuclear Information System (INIS)

    Koeppe, R.A.; Holden, J.E.

    1984-01-01

    An improved method for the reconstruction of emission computed axial tomography images has been developed. The method is a modification of filtered back-projection, where the back projected values are weighted to reflect the loss of formation, with distance from the camera, which is inherent in gamma camera imaging. This information loss is a result of: loss of spatial resolution with distance, attenuation, and scatter. The weighting scheme can best be described by considering the contributions of any two opposing views to the reconstruction image pixels. The weight applied to the projections of one view is set to equal the relative amount of the original activity that was initially received in that projection, assuming a uniform attenuating medium. This yields a weighting value which is a function of distance into the image with a value of one for pixels ''near the camera'', a value of .5 at the image center, and a value of zero on the opposite side. Tomographic reconstructions produced with this method show improved spatial resolution when compared to conventional 360 0 reconstructions. The improvement is in the tangential direction, where simulations have indicated a FWHM improvement of 1 to 1.5 millimeters. The resolution in the radial direction is essentially the same for both methods. Visual inspection of the reconstructed images show improved resolution and contrast

  15. Development of the two Korean adult tomographic computational phantoms for organ dosimetry

    International Nuclear Information System (INIS)

    Lee, Choonsik; Lee, Choonik; Park, Sang-Hyun; Lee, Jai-Ki

    2006-01-01

    Following the previously developed Korean tomographic phantom, KORMAN, two additional whole-body tomographic phantoms of Korean adult males were developed from magnetic resonance (MR) and computed tomography (CT) images, respectively. Two healthy male volunteers, whose body dimensions were fairly representative of the average Korean adult male, were recruited and scanned for phantom development. Contiguous whole body MR images were obtained from one subject exclusive of the arms, while whole-body CT images were acquired from the second individual. A total of 29 organs and tissues and 19 skeletal sites were segmented via image manipulation techniques such as gray-level thresholding, region growing, and manual drawing, in which each of segmented image slice was subsequently reviewed by an experienced radiologist for anatomical accuracy. The resulting phantoms, the MR-based KTMAN-1 (Korean Typical MAN-1) and the CT-based KTMAN-2 (Korean Typical MAN-2), consist of 300x150x344 voxels with a voxel resolution of 2x2x5 mm 3 for both phantoms. Masses of segmented organs and tissues were calculated as the product of a nominal reference density, the prevoxel volume, and the cumulative number of voxels defining each organs or tissue. These organs masses were then compared with those of both the Asian and the ICRP reference adult male. Organ masses within both KTMAN-1 and KTMAN-2 showed differences within 40% of Asian and ICRP reference values, with the exception of the skin, gall bladder, and pancreas which displayed larger differences. The resulting three-dimensional binary file was ported to the Monte Carlo code MCNPX2.4 to calculate organ doses following external irradiation for illustrative purposes. Colon, lung, liver, and stomach absorbed doses, as well as the effective dose, for idealized photon irradiation geometries (anterior-posterior and right lateral) were determined, and then compared with data from two other tomographic phantoms (Asian and Caucasian), and

  16. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification relates to a tomographic scanning apparatus using a fan beam and digital output signal, and particularly to the design of the gas-pressurized ionization detection system. (U.K.)

  17. 4-D tomographic monitoring of enhanced oil recovery

    International Nuclear Information System (INIS)

    Brzostowski, M.A.; McMechan, G.A.

    1991-01-01

    One application of tomography that has recently received considerable attention is reservoir monitoring for Enhanced Oil Recovery (EOR). Tomographic monitoring of a moving steam front uses the significant decrease in compressional wave velocity that occurs as hydrocarbon temperature increases. The purposes of this paper are to present a working algorithm for 3-D tomography, to demonstrate the feasibility of 3-D imaging of a simulated reservoir in which the position of a steam front changes with time, and to illustrate the relations between survey geometry and the resolution of the target

  18. Detectability in the presence of computed tomographic reconstruction noise

    International Nuclear Information System (INIS)

    Hanson, K.M.

    1977-01-01

    The multitude of commercial computed tomographic (CT) scanners which have recently been introduced for use in diagnostic radiology has given rise to a need to compare these different machines in terms of image quality and dose to the patient. It is therefore desirable to arrive at a figure of merit for a CT image which gives a measure of the diagnostic efficacy of that image. This figure of merit may well be dependent upon the specific visual task being performed. It is clearly important that the capabilities and deficiencies of the human observer as well as the interface between man and machine, namely the viewing system, be taken into account in formulating the figure of merit. Since the CT reconstruction is the result of computer processing, it is possible to use this processing to alter the characteristics of the displayed images. This image processing may improve or degrade the figure of merit

  19. Added value of contrast-enhanced ultrasound on biopsies of focal hepatic lesions invisible on fusion imaging guidance

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae Wook; Lee, Min Woo; Song, Kyoung Doo; Kim, Mimi; Kim, Seung Soo; Kim, Seong Hyun; Ha, Sang Yun [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2017-01-15

    To assess whether contrast-enhanced ultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making. The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed. Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5–1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p < 0.001). The technical success rate of biopsy was 87.6% (14/16). After biopsy, there were changes in clinical decision making for 11 of 16 patients (68.8%). The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making.

  20. Added value of contrast-enhanced ultrasound on biopsies of focal hepatic lesions invisible on fusion imaging guidance

    International Nuclear Information System (INIS)

    Kang, Tae Wook; Lee, Min Woo; Song, Kyoung Doo; Kim, Mimi; Kim, Seung Soo; Kim, Seong Hyun; Ha, Sang Yun

    2017-01-01

    To assess whether contrast-enhanced ultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making. The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed. Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5–1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p < 0.001). The technical success rate of biopsy was 87.6% (14/16). After biopsy, there were changes in clinical decision making for 11 of 16 patients (68.8%). The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making

  1. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are presented of a tomographic scanning apparatus, its rotational assembly, and the control and circuit elements, with particular reference to the amplifier and multiplexing circuits enabling detector signal calibration. (U.K.)

  2. Neural network analysis for geological interpretation of tomographic images beneath the Japan Islands

    Science.gov (United States)

    Kuwatani, T.; Toriumi, M.

    2009-12-01

    prediction of lithology and its structure, we will use the additional input data sets, such as tomographic images of random velocity fluctuation (Takahashi et al. 2009) and b-value mapping data. Additionally, different kinds of data sets, including the experimental and petrological results (e.g. Christensen 1991; Hacker et al. 2003) can be applied to our analyses.

  3. Tomographic reconstruction by using FPSIRT (Fast Particle System Iterative Reconstruction Technique)

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Icaro Valgueiro M.; Melo, Silvio de Barros; Dantas, Carlos; Lima, Emerson Alexandre; Silva, Ricardo Martins; Cardoso, Halisson Alberdan C., E-mail: ivmm@cin.ufpe.br, E-mail: sbm@cin.ufpe.br, E-mail: rmas@cin.ufpe.br, E-mail: hacc@cin.ufpe.br, E-mail: ccd@ufpe.br, E-mail: eal@cin.ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    The PSIRT (Particle System Iterative Reconstruction Technique) is a method of tomographic image reconstruction primarily designed to work with configurations suitable for industrial applications. A particle system is an optimization technique inspired in real physical systems that associates to the reconstructing material a set of particles with certain physical features, subject to a force eld, which can produce movement. The system constantly updates the set of particles by repositioning them in such a way as to approach the equilibrium. The elastic potential along a trajectory is a function of the difference between the attenuation coefficient in the current configuration and the corresponding input data. PSIRT has been successfully used to reconstruct simulated and real objects subject to sets of parallel and fanbeam lines in different angles, representing typical gamma-ray tomographic arrangements. One of PSIRT's limitation was its performance, too slow for real time scenarios. In this work, it is presented a reformulation in PSIRT's computational model, which is able to grant the new algorithm, the FPSIRT - Fast System Iterative Reconstruction Technique, a performance up to 200-time faster than PSIRT's. In this work a comparison of their application to real and simulated data from the HSGT, High Speed Gamma Tomograph, is presented. (author)

  4. Tomographic reconstruction by using FPSIRT (Fast Particle System Iterative Reconstruction Technique)

    International Nuclear Information System (INIS)

    Moreira, Icaro Valgueiro M.; Melo, Silvio de Barros; Dantas, Carlos; Lima, Emerson Alexandre; Silva, Ricardo Martins; Cardoso, Halisson Alberdan C.

    2015-01-01

    The PSIRT (Particle System Iterative Reconstruction Technique) is a method of tomographic image reconstruction primarily designed to work with configurations suitable for industrial applications. A particle system is an optimization technique inspired in real physical systems that associates to the reconstructing material a set of particles with certain physical features, subject to a force eld, which can produce movement. The system constantly updates the set of particles by repositioning them in such a way as to approach the equilibrium. The elastic potential along a trajectory is a function of the difference between the attenuation coefficient in the current configuration and the corresponding input data. PSIRT has been successfully used to reconstruct simulated and real objects subject to sets of parallel and fanbeam lines in different angles, representing typical gamma-ray tomographic arrangements. One of PSIRT's limitation was its performance, too slow for real time scenarios. In this work, it is presented a reformulation in PSIRT's computational model, which is able to grant the new algorithm, the FPSIRT - Fast System Iterative Reconstruction Technique, a performance up to 200-time faster than PSIRT's. In this work a comparison of their application to real and simulated data from the HSGT, High Speed Gamma Tomograph, is presented. (author)

  5. A tomographic particle image velocimetry investigation of the flow development over dual step cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Morton, C., E-mail: chris.morton@ucalgary.ca [Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Dr NW, Calgary, Alberta T2N 1N4 (Canada); Yarusevych, S. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave W, Waterloo, Ontario N2L 3G1 (Canada); Scarano, F. [Department of Aerospace Engineering, Delft University of Technology, 2628 Delft (Netherlands)

    2016-02-15

    This experimental study focuses on the near wake development of a dual step cylinder geometry consisting of a long base cylinder of diameter d to which a larger diameter (D) cylinder of length L is attached coaxially at mid-span. The experiments cover a range of Reynolds numbers, 2000 ≤ Re{sub D} ≤ 5000, diameter ratios, 1.33 ≤ D/d ≤ 2.0 and large cylinder aspect ratios, 0.5 ≤ L/D ≤ 5 using Tomographic particle image velocimetry. Distinct changes in wake topology are observed varying the above parameters. Supporting previous experimental studies on the same geometry involving flow visualization and planar measurements, four distinct flow regimes are identified to which a distinct three-dimensional wake topology can be associated. The vortex-dominated wake dynamical behaviour is investigated with Proper Orthogonal Decomposition (POD) and conditional averaging of three-dimensional velocity fields is used to exemplify the different shedding regimes. The conditionally averaged flow fields are shown to quantitatively resolve flow features equivalent to those obtained from a reduced order model consisting of the first ten to twenty POD modes, identifying the dominant vortex shedding cells and their interactions.

  6. Computed tomographic diagnosis of calcified inferior vena cava thrombus in a child with Wilm's tumor

    Energy Technology Data Exchange (ETDEWEB)

    Kirks, D R; Ponzi, J W; Korobkin, M

    1980-01-01

    A calcified thrombus in the inferior vena cava of infants and children may be imaged by computed tomography. The precise location of the calcification within the inferior vena cava may be confirmed by computed tomographic scanning during injection of intravenous contrast material.

  7. Computer tomographic diagnosis of echinococcosis

    Energy Technology Data Exchange (ETDEWEB)

    Haertel, M.; Fretz, C.; Fuchs, W.A.

    1980-08-01

    The computer tomographic appearances and differential diagnosis in 22 patients with echinococcosis are described; of these, twelve were of the cystic and ten of the alveolar type. The computer tomographic appearances are characterised by the presence of daughter cysts (66%) within the sharply demarkated parasitic cyst of water density. In the absence of daughter cysts, a definite aetiological diagnosis cannot be made, although there is a tendency to clasification of the occassionally multiple echinococcus cysts. The computer tomographic appearances of advanced alveolar echinococcosis are characterised by partial collequative necrosis, with clacification around the necrotic areas (90%). The absence of CT evidence of partial necrosis and calsification of the pseudotumour makes it difficult to establish a specific diagnosis. The conclusive and non-invasive character of the procedure and its reproducibility makes computer tomography the method of choice for the diagnosis and follow-up of echinococcosis.

  8. Evaluation of paranasal sinus mucosa in coal worker's pneumoconiosis - A computed tomographic study

    Energy Technology Data Exchange (ETDEWEB)

    Ozdemir, H.; Altin, R.; Mahmutyazicioglu, K.; Kart, L.; Uzun, L.; Savranlar, A.; Davcanci, H.; Gundogdu, S. [Zonguldak Karaelmas University, Zonguldak (Turkey). School of Medicine

    2004-09-01

    Objective: To evaluate by computed tomographic scanning the paranasal mucosal changes of coal workers with and without pneumoconiosis. Methods: Examination of images and scores from paranasal computed tomographic scans. The study participants were 26 coal workers with pneumoconiosis, 29 coal workers without pneumoconiosis, and 20 controls. All were men. The extent and patterns of inflamatory paranasal sinus disease were evaluated on computed, tomographic scans by 2 radiologists using the terminology and definitions of Newman and associates. Results: Interobserver agreement for the presence of abnormalities was from good to excellent (K, 0.63-0.89). The mucosal scores of individuals and groups were higher for coal workers than for control subjects. Both scores were significantly higher in the pneumoconiosis group than in the 2 other groups. Conclusions: This study shows that paranasal sinuses were affected more severely in coal workers than in control subjects. In coal workers with pneumoconiosis, the affection was most severe. The relationship between coal dust exposure and paranasal mucosal changes needs further study.

  9. MO-AB-BRA-02: A Novel Scatter Imaging Modality for Real-Time Image Guidance During Lung SBRT

    International Nuclear Information System (INIS)

    Redler, G; Bernard, D; Templeton, A; Chu, J; Nair, C Kumaran; Turian, J

    2015-01-01

    approach, employing multiple simulation techniques and experiments, is taken to demonstrate the feasibility of a novel scatter imaging modality for the necessary real-time image guidance

  10. MO-AB-BRA-02: A Novel Scatter Imaging Modality for Real-Time Image Guidance During Lung SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Redler, G; Bernard, D; Templeton, A; Chu, J [Rush University Medical Center, Chicago, IL (United States); Nair, C Kumaran [University of Chicago, Chicago, IL (United States); Turian, J [Rush University Medical Center, Chicago, IL (United States); Rush Radiosurgery LLC, Chicago, IL (United States)

    2015-06-15

    approach, employing multiple simulation techniques and experiments, is taken to demonstrate the feasibility of a novel scatter imaging modality for the necessary real-time image guidance.

  11. Quantification of wall motion and phase of contraction in tomographic gated blood pool studies using length-based Fourier analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kenichi; Bunko, Hisashi; Taki, Junichi; Nambu, Ichiro; Shiire, Yasushi; Tonami, Norihisa; Hisada, Kinichi; Tada, Akira; Kojima, Kazuhkio

    1985-03-01

    Length-based Fourier analysis, a new method for quantification of wall motion and timing of contraction, was applied to tomographic gated blood pool study. Two parameters, percent-length shortening (%LS) and length-based phase were calculated based on the time-length curves from a center to ventricular edges, and compared with the count-based method. In mathematical models for tomographic gated blood pool images, the severity of asynergy was easily determined by length-based method, and the accuracy of the parameters was good. As to the setting of the center, fixed center provided more reliable parameters than the method using movable center, i.e., when a center of gravity was determined in each frame. By length-based Fourier analysis, quantification of wall motion was easily performed, and the initial inward movement caused by the accessory conduction pathway was assessed in patients with Wolff-Parkinson-White syndrome. Length-based approach was considered to be reasonable and effective because the movements of the ventricular edges are essential in tomographic gated blood pool images.

  12. Quantification of wall motion and phase of contraction in tomographic gated blood pool studies using length-based Fourier analysis

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Taki, Junichi; Nambu, Ichiro; Shiire, Yasushi; Tonami, Norihisa; Hisada, Kinichi; Tada, Akira; Kojima, Kazuhiko.

    1985-01-01

    Length-based Fourier analysis, a new method for quantification of wall motion and timing of contraction, was applied to tomographic gated blood pool study. Two parameters, percent-length shortening (%LS) and length-based phase were calculated based on the time-length curves from a center to ventricular edges, and compared with the count-based method. In mathematical models for tomographic gated blood pool images, the severity of asynergy was easily determined by length-based method, and the accuracy of the parameters was good. As to the setting of the center, fixed center provided more reliable parameters than the method using movable center, i.e., when a center of gravity was determined in each frame. By length-based Fourier analysis, quantification of wall motion was easily performed, and the initial inward movement caused by the accessory conduction pathway was assessed in patients with Wolff-Parkinson-White syndrome. Length-based approach was considered to be reasonable and effective because the movements of the ventricular edges are essential in tomographic gated blood pool images. (author)

  13. Tomographic site characterization using CPT, ERT, and GPR. Innovative Technology Summary Report

    International Nuclear Information System (INIS)

    None

    2000-01-01

    ARA developed a geophysical tomographic system that incorporates results from Electrical Resistivity Tomography (ERT) measurements and Ground Penetrating Radar (GPR) Tomography measurements. Both methods are useful for imaging subsurface structures and processes, however, GPR is more effective in sandy material and ERT is more effective in clayey material. CPT or drilling is used to deploy the electrodes in the subsurface

  14. Preoperative magnetic resonance imaging protocol for endoscopic cranial base image-guided surgery.

    Science.gov (United States)

    Grindle, Christopher R; Curry, Joseph M; Kang, Melissa D; Evans, James J; Rosen, Marc R

    2011-01-01

    Despite the increasing utilization of image-guided surgery, no radiology protocols for obtaining magnetic resonance (MR) imaging of adequate quality are available in the current literature. At our institution, more than 300 endonasal cranial base procedures including pituitary, extended pituitary, and other anterior skullbase procedures have been performed in the past 3 years. To facilitate and optimize preoperative evaluation and assessment, there was a need to develop a magnetic resonance protocol. Retrospective Technical Assessment was performed. Through a collaborative effort between the otolaryngology, neurosurgery, and neuroradiology departments at our institution, a skull base MR image-guided (IGS) protocol was developed with several ends in mind. First, it was necessary to generate diagnostic images useful for the more frequently seen pathologies to improve work flow and limit the expense and inefficiency of case specific MR studies. Second, it was necessary to generate sequences useful for IGS, preferably using sequences that best highlight that lesion. Currently, at our institution, all MR images used for IGS are obtained using this protocol as part of preoperative planning. The protocol that has been developed allows for thin cut precontrast and postcontrast axial cuts that can be used to plan intraoperative image guidance. It also obtains a thin cut T2 axial series that can be compiled separately for intraoperative imaging, or may be fused with computed tomographic images for combined modality. The outlined protocol obtains image sequences effective for diagnostic and operative purposes for image-guided surgery using both T1 and T2 sequences. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. SU-E-I-39: Combining Conventional Tomographic Imaging Strategy and Interior Tomography for Low Dose Dual-Energy CT (DECT)

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q [School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Xing, L [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Xiong, G; Elmore, K; Min, J [Dalio Institute of Cardiovascular Imaging, New York- Presbyterian Hospital and Weill Cornell Medical College, New York, NY (United States)

    2015-06-15

    Purpose: Dual-energy CT (DECT) affords quantitative information of tissue density and provides a new dimension for disease diagnosis and treatment planning. The technique, however, increases the imaging dose because of the doubled scans, and thus hinders its widespread clinical applications. The purpose of this work is to develop a novel hybrid DECT image acquisition and reconstruction strategy, in which one of the energies is dealt by interior tomography while the other one is obtained using conventional tomography approach. Methods: In the proposed hybrid imaging strategy, the projection data of one of the energies (e.g., high-energy) were acquired and processed in an interior scanning model, whereas the other energy in the conventional tomographic approach. It known that, if the ROI is piecewise constant or polynomial, the interior ROI can be reconstructed with TV or HOT minimization. Here we extend the TV based interior reconstruction method into dual-energy situation. The ROI images so obtained were overlaid in the context of conventional CT of the companion energy. A material based composition in ROI was used in the proposed reconstruction framework. Results: In the simulation experiment with a diagnostic DECT geometry and energies, we were able to derive the densities of soft-tissues and bones in the ROI with high fidelity. In the experimental CBCT study, both kV and MV data were collected using the on-board kV and MV imaging system. The MV data were truncated only across the ROI. Using the interior tomography reconstruction above, we were able to obtain the ROI images as that obtained using un-truncated MV data with known tissue densities. Conclusion: The proposed DECT imaging strategy provides an effective way to extract tissue density information in the ROI and in the context of anatomical images of CT imaging, with much reduced imaging dose.

  16. Fine Guidance Sensing for Coronagraphic Observatories

    Science.gov (United States)

    Brugarolas, Paul; Alexander, James W.; Trauger, John T.; Moody, Dwight C.

    2011-01-01

    Three options have been developed for Fine Guidance Sensing (FGS) for coronagraphic observatories using a Fine Guidance Camera within a coronagraphic instrument. Coronagraphic observatories require very fine precision pointing in order to image faint objects at very small distances from a target star. The Fine Guidance Camera measures the direction to the target star. The first option, referred to as Spot, was to collect all of the light reflected from a coronagraph occulter onto a focal plane, producing an Airy-type point spread function (PSF). This would allow almost all of the starlight from the central star to be used for centroiding. The second approach, referred to as Punctured Disk, collects the light that bypasses a central obscuration, producing a PSF with a punctured central disk. The final approach, referred to as Lyot, collects light after passing through the occulter at the Lyot stop. The study includes generation of representative images for each option by the science team, followed by an engineering evaluation of a centroiding or a photometric algorithm for each option. After the alignment of the coronagraph to the fine guidance system, a "nulling" point on the FGS focal point is determined by calibration. This alignment is implemented by a fine alignment mechanism that is part of the fine guidance camera selection mirror. If the star images meet the modeling assumptions, and the star "centroid" can be driven to that nulling point, the contrast for the coronagraph will be maximized.

  17. Caveats on tomographic images

    DEFF Research Database (Denmark)

    Foulger, Gillian R.; Panza, Giuliano F.; Artemieva, Irina

    2013-01-01

    Geological and geodynamic models of the mantle often rely on joint interpretations of published seismic tomography images and petrological/geochemical data. This approach tends to neglect the fundamental limitations of, and uncertainties in, seismic tomography results. These limitations and uncer...

  18. Utility of cervical spinal and abdominal computed tomography in diagnosing occult pneumothorax in patients with blunt trauma: Computed tomographic imaging protocol matters.

    Science.gov (United States)

    Akoglu, Haldun; Akoglu, Ebru Unal; Evman, Serdar; Akoglu, Tayfun; Denizbasi, Arzu; Guneysel, Ozlem; Onur, Ozge; Onur, Ender

    2012-10-01

    Small pneumothoraces (PXs), which are not initially recognized with a chest x-ray film and diagnosed by a thoracic computed tomography (CT), are described as occult PX (OCPX). The objective of this study was to evaluate cervival spine (C-spine) and abdominal CT (ACT) for diagnosing OCPX and overt PX (OVPX). All patients with blunt trauma who presented consecutively to the emergency department during a 26-months period were included. Among all the chest CTs (CCTs) (6,155 patients) conducted during that period, 254 scans were confirmed to have a true PX. The findings in their C-spine CT and ACT were compared with the findings in CCTs. Among these patients, 254 had a diagnosis of PX confirmed with CCT. OCPXs were identified on the chest computed tomographic scan of 128 patients (70.3%), whereas OVPXs were evident in 54 patients (29.7%). Computed tomographic imaging of the C-spine was performed in 74% of patients with OCPX and 66.7% of patients with OVPX trauma. Only 45 (35.2%) cases of OCPX and 42 (77.8%) cases of OVPX were detected by C-spine CT. ACT was performed in almost all patients, and 121 (95.3%) of 127 of these correctly identified an existing OCPX. Sensitivity of C-spine CT and ACT was 35.1% and 96.5%, respectively; specificity was 100% and 100%, respectively. Almost all OCPXs, regardless of intrathoracic location, could be detected by ACT or by combining C-spine and abdominal computed tomographic screening for patients. If the junction of the first and second vertebra is used as the caudad extent, C-spine CT does not have sufficient power to diagnose more than a third of the cases. Diagnostic study, level III.

  19. Bayesian image processing in two and three dimensions

    International Nuclear Information System (INIS)

    Hart, H.; Liang, Z.

    1986-01-01

    Tomographic image processing customarily analyzes data acquired over a series of projective orientations. If, however, the point source function (the matrix R) of the system is strongly depth dependent, tomographic information is also obtainable from a series of parallel planar images corresponding to different ''focal'' depths. Bayesian image processing (BIP) was carried out for two and three dimensional spatially uncorrelated discrete amplitude a priori source distributions

  20. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification describes a tomographic scanning apparatus, with particular reference to the adjustable fan beam and its collimator system, together with the facility for taking a conventional x-radiograph without moving the patient. (U.K.)

  1. DG TOMO: A new method for tomographic reconstruction

    International Nuclear Information System (INIS)

    Freitas, D. de; Feschet, F.; Cachin, F.; Geissler, B.; Bapt, A.; Karidioula, I.; Martin, C.; Kelly, A.; Mestas, D.; Gerard, Y.; Reveilles, J.P.; Maublant, J.

    2006-01-01

    Aim: FBP and OSEM are the most popular tomographic reconstruction methods in scintigraphy. FBP is a simple method but artifacts of reconstruction are generated which corrections induce degradation of the spatial resolution. OSEM takes account of statistical fluctuations but noise strongly increases after a certain number of iterations. We compare a new method of tomographic reconstruction based on discrete geometry (DG TOMO) to FBP and OSEM. Materials and methods: Acquisitions were performed on a three-head gamma-camera (Philips) with a NEMA Phantom containing six spheres of sizes from 10 to 37 mm inner diameter, filled with around 325 MBq/l of technetium-99 m. The spheres were positioned in water containing 3 MBq/l of technetium-99 m. Acquisitions were realized during a 180 o -rotation around the phantom by 25-s steps. DG TOMO has been developed in our laboratory in order to minimize the number of projections at acquisition. Two tomographic reconstructions utilizing 32 and 16 projections with FBP, OSEM and DG TOMO were performed and transverse slices were compared. Results: FBP with 32 projections detects only the activity in the three largest spheres (diameter ≥22 mm). With 16 projections, the star effect is predominant and the contrast of the third sphere is very low. OSEM with 32 projections provides a better image but the three smallest spheres (diameter ≤17 mm) are difficult to distinguish. With 16 projections, the three smaller spheres are not detectable. The results of DG TOMO are similar to OSEM. Conclusion: Since the parameters of DG TOMO can be further optimized, this method appears as a promising alternative for tomoscintigraphy reconstruction

  2. Virtual Ultrasound Guidance for Inexperienced Operators

    Science.gov (United States)

    Caine, Timothy; Martin, David

    2012-01-01

    Medical ultrasound or echocardiographic studies are highly operator-dependent and generally require lengthy training and internship to perfect. To obtain quality echocardiographic images in remote environments, such as on-orbit, remote guidance of studies has been employed. This technique involves minimal training for the user, coupled with remote guidance from an expert. When real-time communication or expert guidance is not available, a more autonomous system of guiding an inexperienced operator through an ultrasound study is needed. One example would be missions beyond low Earth orbit in which the time delay inherent with communication will make remote guidance impractical. The Virtual Ultrasound Guidance system is a combination of hardware and software. The hardware portion includes, but is not limited to, video glasses that allow hands-free, full-screen viewing. The glasses also allow the operator a substantial field of view below the glasses to view and operate the ultrasound system. The software is a comprehensive video program designed to guide an inexperienced operator through a detailed ultrasound or echocardiographic study without extensive training or guidance from the ground. The program contains a detailed description using video and audio to demonstrate equipment controls, ergonomics of scanning, study protocol, and scanning guidance, including recovery from sub-optimal images. The components used in the initial validation of the system include an Apple iPod Classic third-generation as the video source, and Myvue video glasses. Initially, the program prompts the operator to power-up the ultrasound and position the patient. The operator would put on the video glasses and attach them to the video source. After turning on both devices and the ultrasound system, the audio-video guidance would then instruct on patient positioning and scanning techniques. A detailed scanning protocol follows with descriptions and reference video of each view along with

  3. Brain spect imaging

    International Nuclear Information System (INIS)

    Lee, R.G.L.; Hill, T.C.; Holman, B.L.

    1989-01-01

    This paper discusses how the rapid development of single-photon radiopharmaceuticals has given new life to tomographic brain imaging in nuclear medicine. Further developments in radiopharmaceuticals and refinements in neuro-SPECT (single-photon emission computed tomography) instrumentation should help to reinstate brain scintigraphy as an important part of neurologic diagnosis. SPECT of the brain evolved from experimentation using prototype instrumentation during the early 1960s. Although tomographic studies provided superior diagnostic accuracy when compared to planar techniques, the arrival of X-ray CT of the head resulted in the rapid demise of technetium brain imaging

  4. Precision tomographic analysis of reactor fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Deok; Lee, Chang Hee; Kim, Jong Soo; Jeong, Jwong Hwan; Nam, Ki Yong

    2001-03-01

    For the tomographical assay, search of current status, analysis of neutron beam characteristics, MCNP code simulation, sim-fuel fabrication, neutron experiment for sim-fuel, multiaxes operation system design were done. In sensitivity simulation, the reconstruction results showed the good agreement. Also, the scoping test at ANL was very helpful for actual assay. Therefore, the results are applied for HANARO tomographical system setup and consecutive next research.

  5. Precision tomographic analysis of reactor fuels

    International Nuclear Information System (INIS)

    Lee, Yong Deok; Lee, Chang Hee; Kim, Jong Soo; Jeong, Jwong Hwan; Nam, Ki Yong

    2001-03-01

    For the tomographical assay, search of current status, analysis of neutron beam characteristics, MCNP code simulation, sim-fuel fabrication, neutron experiment for sim-fuel, multiaxes operation system design were done. In sensitivity simulation, the reconstruction results showed the good agreement. Also, the scoping test at ANL was very helpful for actual assay. Therefore, the results are applied for HANARO tomographical system setup and consecutive next research

  6. Axial tomographic scanner

    International Nuclear Information System (INIS)

    1976-01-01

    An axial tomographic system is described comprising axial tomographic means for collecting sets of data corresponding to the transmission or absorption of a number of beams of penetrating radiation through a planar slice of an object. It includes means to locate an object to be analyzed, a source and detector for directing one or more beams of penetrating radiation through the object from the source to the detector, and means to rotate (and optionally translate) the source as well as means to process the collected sets of data. Data collection, data processing, and data display can each be conducted independently of each other. An additional advantage of the system described is that the raw data (i.e., the originally collected data) are not destroyed by the data processing but instead are retained intact for further reference or use, if needed

  7. Use of a hybrid iterative reconstruction technique to reduce image noise and improve image quality in obese patients undergoing computed tomographic pulmonary angiography.

    Science.gov (United States)

    Kligerman, Seth; Mehta, Dhruv; Farnadesh, Mahmmoudreza; Jeudy, Jean; Olsen, Kathryn; White, Charles

    2013-01-01

    To determine whether an iterative reconstruction (IR) technique (iDose, Philips Healthcare) can reduce image noise and improve image quality in obese patients undergoing computed tomographic pulmonary angiography (CTPA). The study was Health Insurance Portability and Accountability Act compliant and approved by our institutional review board. A total of 33 obese patients (average body mass index: 42.7) underwent CTPA studies following standard departmental protocols. The data were reconstructed with filtered back projection (FBP) and 3 iDose strengths (iDoseL1, iDoseL3, and iDoseL5) for a total of 132 studies. FBP data were collected from 33 controls (average body mass index: 22) undergoing CTPA. Regions of interest were drawn at 6 identical levels in the pulmonary artery (PA), from the main PA to a subsegmental branch, in both the control group and study groups using each algorithm. Noise and attenuation were measured at all PA levels. Three thoracic radiologists graded each study on a scale of 1 (very poor) to 5 (ideal) by 4 categories: image quality, noise, PA enhancement, and "plastic" appearance. Statistical analysis was performed using an unpaired t test, 1-way analysis of variance, and linear weighted κ. Compared with the control group, there was significantly higher noise with FBP, iDoseL1, and iDoseL3 algorithms (Pnoise in the control group and iDoseL5 algorithm in the study group. Analysis within the study group showed a significant and progressive decrease in noise and increase in the contrast-to-noise ratio as the level of IR was increased (Pnoise and PA enhancement with increasing levels of iDose. The use of an IR technique leads to qualitative and quantitative improvements in image noise and image quality in obese patients undergoing CTPA.

  8. Monitoring of health of trees by gamma-ray tomographic scanners and the first Kanpur error theorem

    International Nuclear Information System (INIS)

    Verma, Ruchi; Razdan, Mayuri; Quraishi, A.M.; Munshi, Prabhat

    2004-01-01

    CT scanners produce nondestructively images of a given cross-section with the help of radiation source-detector system and a suitable tomographic reconstruction algorithm. These CT images have inherent error associated with them and for unknown objects it is not possible to calculate it directly. Careful application of the first Kanpur theorem, however, gives an indirect estimate of the inaccuracy of these images. An interesting outcome of this theorem is monitoring of health of trees. (author)

  9. Tomographic visualization of stress corrosion cracks in tubing

    International Nuclear Information System (INIS)

    Morris, R.A.; Kruger, R.P.; Wecksung, G.W.

    1979-06-01

    A feasibility study was conducted to determine the possibility of detecting and sizing cracks in reactor cooling water tubes using tomographic techniques. Due to time and financial constraints, only one tomographic reconstruction using the best technique available was made. The results indicate that tomographic reconstructions can, in fact, detect cracks in the tubing and might possibly be capable of measuring the depth of the cracks. Limits of detectability and sensitivity have not been determined but should be investigated in any future work

  10. Three-dimensional analysis and display of medical images

    International Nuclear Information System (INIS)

    Bajcsy, R.

    1985-01-01

    Until recently, the most common medical images were X-rays on film analyzed by an expert, ususally a radiologist, who used, in addition to his/her visual perceptual abilities, knowledge obtained through medical studies, and experience. Today, however, with the advent of various imaging techniques, X-ray computerized axial tomographs (CAT), positron emission tomographs (PET), ultrasound tomographs, nuclear magnetic resonance tomographs (NMR), just to mention a few, the images are generated by computers and displayed on computer-controlled devices; so it is appropriate to think about more quantitative and perhaps automated ways of data analysis. Furthermore, since the data are generated by computer, it is only natural to take advantage of the computer for analysis purposes. In addition, using the computer, one can analyze more data and relate different modalities from the same subject, such as, for example, comparing the CAT images with PET images from the same subject. In the next section (The PET Scanner) the authors shall only briefly mention with appropriate references the modeling of the positron emission tomographic scanner, since this imaging technique is not as widely described in the literature as the CAT scanner. The modeling of the interpreter is not going to be mentioned, since it is a topic that by itself deserves a full paper; see, for example, Pizer [1981]. The thrust of this chapter is on modeling the organs that are being imaged and the matching techniques between the model and the data. The image data is from CAT and PET scans. Although the authors believe that their techniques are applicable to any organ of the human body, the examples are only from the brain

  11. WE-D-BRB-03: Current State of Volumetric Image Guidance for Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hua, C. [St. Jude Children’s Research Hospital (United States)

    2016-06-15

    The goal of this session is to review the physics of proton therapy, treatment planning techniques, and the use of volumetric imaging in proton therapy. The course material covers the physics of proton interaction with matter and physical characteristics of clinical proton beams. It will provide information on proton delivery systems and beam delivery techniques for double scattering (DS), uniform scanning (US), and pencil beam scanning (PBS). The session covers the treatment planning strategies used in DS, US, and PBS for various anatomical sites, methods to address uncertainties in proton therapy and uncertainty mitigation to generate robust treatment plans. It introduces the audience to the current status of image guided proton therapy and clinical applications of CBCT for proton therapy. It outlines the importance of volumetric imaging in proton therapy. Learning Objectives: Gain knowledge in proton therapy physics, and treatment planning for proton therapy including intensity modulated proton therapy. The current state of volumetric image guidance equipment in proton therapy. Clinical applications of CBCT and its advantage over orthogonal imaging for proton therapy. B. Teo, B.K Teo had received travel funds from IBA in 2015.

  12. WE-D-BRB-03: Current State of Volumetric Image Guidance for Proton Therapy

    International Nuclear Information System (INIS)

    Hua, C.

    2016-01-01

    The goal of this session is to review the physics of proton therapy, treatment planning techniques, and the use of volumetric imaging in proton therapy. The course material covers the physics of proton interaction with matter and physical characteristics of clinical proton beams. It will provide information on proton delivery systems and beam delivery techniques for double scattering (DS), uniform scanning (US), and pencil beam scanning (PBS). The session covers the treatment planning strategies used in DS, US, and PBS for various anatomical sites, methods to address uncertainties in proton therapy and uncertainty mitigation to generate robust treatment plans. It introduces the audience to the current status of image guided proton therapy and clinical applications of CBCT for proton therapy. It outlines the importance of volumetric imaging in proton therapy. Learning Objectives: Gain knowledge in proton therapy physics, and treatment planning for proton therapy including intensity modulated proton therapy. The current state of volumetric image guidance equipment in proton therapy. Clinical applications of CBCT and its advantage over orthogonal imaging for proton therapy. B. Teo, B.K Teo had received travel funds from IBA in 2015.

  13. A study of the multiple pinhole coded aperture and the application of the minicomputer in image decoding

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Hashiba, Hiroshi; Akagi, Kiyoshi; Kobayashi, Akitoshi; Matsuda, Magoichi

    1979-01-01

    Research has been done on optically reconstructed imaging employing the Multiple Pinhole Coded Aperture (hereafter abbreviated as MPCA) in radioisotope tomographic imaging. However, problems remain in the optically reconstructed image method. Therefore, we employed a minicomputer (hereafter abbreviated as CPU) and developed the software for decoding and managing the radioisotope tomographic image. Combining the MPCA and the CPU system, we were able to decode and manage the radioisotope tomographic image. 1) In comparison to the optically decoded MPCA image, various input commands are possibly in the CPU method according to the dialogue between the CPU and the on line typewriter. In addition to this, decoded tomographic images of unrestricted depth are readily attainable. 2) In the CPU method noise elimination and other aspects of image management can be easily performed. (author)

  14. Neural network analysis of crosshole tomographic images: The seismic signature of gas hydrate bearing sediments in the Mackenzie Delta (NW Canada)

    Science.gov (United States)

    Bauer, K.; Pratt, R. G.; Haberland, C.; Weber, M.

    2008-10-01

    Crosshole seismic experiments were conducted to study the in-situ properties of gas hydrate bearing sediments (GHBS) in the Mackenzie Delta (NW Canada). Seismic tomography provided images of P velocity, anisotropy, and attenuation. Self-organizing maps (SOM) are powerful neural network techniques to classify and interpret multi-attribute data sets. The coincident tomographic images are translated to a set of data vectors in order to train a Kohonen layer. The total gradient of the model vectors is determined for the trained SOM and a watershed segmentation algorithm is used to visualize and map the lithological clusters with well-defined seismic signatures. Application to the Mallik data reveals four major litho-types: (1) GHBS, (2) sands, (3) shale/coal interlayering, and (4) silt. The signature of seismic P wave characteristics distinguished for the GHBS (high velocities, strong anisotropy and attenuation) is new and can be used for new exploration strategies to map and quantify gas hydrates.

  15. Uniaxial Compression of Cellular Materials at a 10-1 s-1 Strain Rate Simultaneously with Synchrotron X-ray Computed Tomographic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Brian M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-01

    The topic is presented as a series of slides. Motivation for the work included the following: X-ray tomography is a fantastic technique for characterizing a material’s starting structure as well as for non-destructive, in situ experiments to investigate material response; 3D X-ray tomography is needed to fully characterize the morphology of cellular materials; and synchrotron micro-CT can capture 3D images without pausing experiment. Among the conclusions reached are these: High-rate radiographic and tomographic imaging (0.25 s 3D frame rate) using synchrotron CT can capture full 3D images of hyper-elastic materials at a 10-2 strain rate; dynamic true in situ uniaxial loading can be accurately captured; the three stages of compression can be imaged: bending, buckling, and breaking; implementation of linear modeling is completed; meshes have been imported into LANL modeling codes--testing and validation is underway and direct comparison and validation between in situ data and modeled mechanical response is possible.

  16. Imaging-guided and nonimaging-guided fine needle aspiration of liver lesions: experience with 406 patients.

    Science.gov (United States)

    Edoute, Y; Tibon-Fisher, O; Ben-Haim, S A; Malberger, E

    1991-12-01

    The aim of the present study was to determine the diagnostic accuracy of different modes of fine needle aspiration (FNA) of liver lesions. A total of 492 FNAs were performed on 406 patients in order to confirm or to rule out focal or multifocal neoplastic disease: 29% under ultrasound (US) guidance, 3% with computed tomographic (CT) guidance, 67% preoperatively, and 1% intraoperatively without imaging guidance. Based on histologic, cytologic, and clinical findings, final diagnoses were reached in 387 patients, of whom 264 had malignant liver disease and 123 had benign liver disease. Of 321 aspirations performed in patients with malignant liver disease, the cytologic findings suggested malignancy in 225 (70.1%), suspected malignancy in 25 (7.8%), and did not reveal malignancy in 71 aspirations (22.1%). Among the 123 patients with benign liver disease, the cytologic findings were reported as benign in all but two patients, who had false-positive cytologic findings. The overall sensitivity, specificity, positive, and negative predictive values for cytologic findings were 85.6, 98.4, 99.1, and 76.1%, respectively. The overall diagnostic accuracy was 89.7%. In one patient, fatal intraperitoneal bleeding due to chronic intravascular coagulation complicated the FNA procedure. We conclude that imaging-guided FNA as well as nonguided FNA for cytologic diagnosis of liver lesions are highly accurate and only rarely may be associated with a fatal complication.

  17. The CDD system in computed tomographic diagnosis of diverticular disease; Das CDD-System in der computertomografischen Diagnostik der Divertikelkrankheit

    Energy Technology Data Exchange (ETDEWEB)

    Pustelnik, Daniel; Elsholtz, Fabian Henry Juergen; Hamm, Bernd; Niehues, Stefan Markus [Charite - Universitaetsmedizin, Berlin (Germany). Inst. of Radiology; Bojarski, Christian [Charite - Universitaetsmedizin, Berlin (Germany). Div. of Gastroenterology, Infectiology and Rheumatology

    2017-08-15

    Purpose cation in computed tomographic diagnosis and briefly recapitulates its targeted advantages over preliminary systems. Primarily, application of the CDD in computed tomography diagnostics is described. Differences with respect to the categories of the older systems are pointed out on the level of each CDD type using imaging examples. The presented images are derived from our institute according to the S2k criteria. Literature was researched on PubMed. Results The CDD constitutes an improvement compared to older systems for categorizing the stages of diverticular disease. It provides more discriminatory power on the descriptive-morphological level and defines as well as differentiates more courses of the disease. Furthermore, the categories translate more directly into state-of-the-art decision-making concerning hospitalization and therapy. The CDD should be applied routinely in the computed tomographic diagnosis of diverticular disease. Typical imaging patterns are presented.

  18. Computed tomography and three-dimensional imaging

    International Nuclear Information System (INIS)

    Harris, L.D.; Ritman, E.L.; Robb, R.A.

    1987-01-01

    Presented here is a brief introduction to two-, three-, and four-dimensional computed tomography. More detailed descriptions of the mathematics of reconstruction and of CT scanner operation are presented elsewhere. The complementary tomographic imaging methods of single-photon-emission tomography (SPECT) positron-emission tomography (PET), nuclear magnetic resonance (NMR) imaging, ulltrasound sector scanning, and ulltrasound computer-assisted tomography [UCAT] are only named here. Each imaging modality ''probes'' the body with a different energy form, yielding unique and useful information about tomographic sections through the body

  19. Assessment and Development of Microwave Imaging for Breast Cancer Detection

    DEFF Research Database (Denmark)

    Jensen, Peter Damsgaard

    At the Technical University of Denmark (DTU), a 3D tomographic microwave imaging system is currently being developed with the aim of using nonlinear microwave imaging for breast-cancer detection. The imaging algorithm used in the system is based on an iterative Newton-type scheme. In this algorithm...... used in the microwave tomographic imaging system is presented. Non-linear microwave tomographic imaging of the breast is a challenging computational problem. The breast is heterogeneous and contains several high-contrast and lossy regions, resulting in large differences in the measured signal levels....... This implies that special care must be taken when the imaging problem is formulated. Under such conditions, microwave imaging systems will most often be considerably more sensitive to changes in the electromagnetic properties in certain regions of the breast. The result is that the parameters might...

  20. Towards 4D intervention guidance using compressed sensing

    Energy Technology Data Exchange (ETDEWEB)

    Kuntz, Jan; Bartling, Soenke [Deutsches Krebsforschungszentrum DKFZ, Heidelberg (Germany); Brehm, Marcus; Kachelriess, Marc [Erlangen-Nuernberg Univ., Erlangen (Germany). Inst. of Medical Physics (IMP)

    2011-07-01

    Interventional radiology is nowadays usually guided with projection radiography using mono- or biplane systems. Due to the projective nature of this guidance imaging certain intraprocedural situations remain unclear. Although helpful, the use of 3D CT is limited due to radiation dose. Using advanced reconstruction techniques incorporating prior knowledge, one could overcome these limitations without exceeding dose limitations. Intervention guidance is especially appealing to those algorithms, because certain constrains apply to useful images in intervention guidance that vary relevantly from other CT applications. These are: key relevance of high contrast structures, sparse temporal updates and little relevance of absolute CT values. In this paper the principal usability of reconstruction algorithms for intervention guidance is tested. Compressed sensing algorithms PICCS and ASD-POCS are compared to the McKinnon-Bates and Feldkamp-Davis-Kress algorithm. Animal experiments as well as simulations are performed. An outlook towards 4D intervention guidance is provided. (orig.)

  1. Application of THz probe radiation in low-coherent tomographs based on spatially separated counterpropagating beams

    Energy Technology Data Exchange (ETDEWEB)

    Kuritsyn, I I; Shkurinov, A P; Nazarov, M M [Department of Physics, M.V. Lomonosov Moscow State University (Russian Federation); Mandrosov, V I [Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow Region (Russian Federation); Cherkasova, O P [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2013-10-31

    A principle of designing a high-resolution low-coherent THz tomograph, which makes it possible to investigate media with a high spatial resolution (in the range λ{sub 0} – 2λ{sub 0}, where λ{sub 0} is the average probe wavelength) is considered. The operation principle of this tomograph implies probing a medium by radiation with a coherence length of 8λ{sub 0} and recording a hologram of a focused image of a fixed layer of this medium using spatially separated counterpropagating object and reference beams. Tomograms of the medium studied are calculated using a temporal approach based on application of the time correlation function of probe radiation. (terahertz radiation)

  2. A three-dimensional strain measurement method in elastic transparent materials using tomographic particle image velocimetry.

    Directory of Open Access Journals (Sweden)

    Azuma Takahashi

    Full Text Available The mechanical interaction between blood vessels and medical devices can induce strains in these vessels. Measuring and understanding these strains is necessary to identify the causes of vascular complications. This study develops a method to measure the three-dimensional (3D distribution of strain using tomographic particle image velocimetry (Tomo-PIV and compares the measurement accuracy with the gauge strain in tensile tests.The test system for measuring 3D strain distribution consists of two cameras, a laser, a universal testing machine, an acrylic chamber with a glycerol water solution for adjusting the refractive index with the silicone, and dumbbell-shaped specimens mixed with fluorescent tracer particles. 3D images of the particles were reconstructed from 2D images using a multiplicative algebraic reconstruction technique (MART and motion tracking enhancement. Distributions of the 3D displacements were calculated using a digital volume correlation. To evaluate the accuracy of the measurement method in terms of particle density and interrogation voxel size, the gauge strain and one of the two cameras for Tomo-PIV were used as a video-extensometer in the tensile test. The results show that the optimal particle density and interrogation voxel size are 0.014 particles per pixel and 40 × 40 × 40 voxels with a 75% overlap. The maximum measurement error was maintained at less than 2.5% in the 4-mm-wide region of the specimen.We successfully developed a method to experimentally measure 3D strain distribution in an elastic silicone material using Tomo-PIV and fluorescent particles. To the best of our knowledge, this is the first report that applies Tomo-PIV to investigate 3D strain measurements in elastic materials with large deformation and validates the measurement accuracy.

  3. Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions

    International Nuclear Information System (INIS)

    Waspe, Adam C.; McErlain, David D.; Pitelka, Vasek; Holdsworth, David W.; Lacefield, James C.; Fenster, Aaron

    2010-01-01

    Purpose: Preclinical research protocols often require insertion of needles to specific targets within small animal brains. To target biologically relevant locations in rodent brains more effectively, a robotic device has been developed that is capable of positioning a needle along oblique trajectories through a single burr hole in the skull under volumetric microcomputed tomography (micro-CT) guidance. Methods: An x-ray compatible stereotactic frame secures the head throughout the procedure using a bite bar, nose clamp, and ear bars. CT-to-robot registration enables structures identified in the image to be mapped to physical coordinates in the brain. Registration is accomplished by injecting a barium sulfate contrast agent as the robot withdraws the needle from predefined points in a phantom. Registration accuracy is affected by the robot-positioning error and is assessed by measuring the surface registration error for the fiducial and target needle tracks (FRE and TRE). This system was demonstrated in situ by injecting 200 μm tungsten beads into rat brains along oblique trajectories through a single burr hole on the top of the skull under micro-CT image guidance. Postintervention micro-CT images of each skull were registered with preintervention high-field magnetic resonance images of the brain to infer the anatomical locations of the beads. Results: Registration using four fiducial needle tracks and one target track produced a FRE and a TRE of 96 and 210 μm, respectively. Evaluation with tissue-mimicking gelatin phantoms showed that locations could be targeted with a mean error of 154±113 μm. Conclusions: The integration of a robotic needle-positioning device with volumetric micro-CT image guidance should increase the accuracy and reduce the invasiveness of stereotactic needle interventions in small animals.

  4. Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions

    Energy Technology Data Exchange (ETDEWEB)

    Waspe, Adam C.; McErlain, David D.; Pitelka, Vasek; Holdsworth, David W.; Lacefield, James C.; Fenster, Aaron [Biomedical Engineering Graduate Program and Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8 (Canada); Department of Medical Biophysics and Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8 (Canada); Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5C1 (Canada); Biomedical Engineering Graduate Program, Department of Medical Biophysics, Department of Medical Imaging, Department of Surgery, and Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8 (Canada); Biomedical Engineering Graduate Program, Department of Electrical and Computer Engineering, Department of Medical Biophysics, and Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8 (Canada); Biomedical Engineering Graduate Program, Department of Medical Biophysics, Department of Medical Imaging, and Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8 (Canada)

    2010-04-15

    Purpose: Preclinical research protocols often require insertion of needles to specific targets within small animal brains. To target biologically relevant locations in rodent brains more effectively, a robotic device has been developed that is capable of positioning a needle along oblique trajectories through a single burr hole in the skull under volumetric microcomputed tomography (micro-CT) guidance. Methods: An x-ray compatible stereotactic frame secures the head throughout the procedure using a bite bar, nose clamp, and ear bars. CT-to-robot registration enables structures identified in the image to be mapped to physical coordinates in the brain. Registration is accomplished by injecting a barium sulfate contrast agent as the robot withdraws the needle from predefined points in a phantom. Registration accuracy is affected by the robot-positioning error and is assessed by measuring the surface registration error for the fiducial and target needle tracks (FRE and TRE). This system was demonstrated in situ by injecting 200 {mu}m tungsten beads into rat brains along oblique trajectories through a single burr hole on the top of the skull under micro-CT image guidance. Postintervention micro-CT images of each skull were registered with preintervention high-field magnetic resonance images of the brain to infer the anatomical locations of the beads. Results: Registration using four fiducial needle tracks and one target track produced a FRE and a TRE of 96 and 210 {mu}m, respectively. Evaluation with tissue-mimicking gelatin phantoms showed that locations could be targeted with a mean error of 154{+-}113 {mu}m. Conclusions: The integration of a robotic needle-positioning device with volumetric micro-CT image guidance should increase the accuracy and reduce the invasiveness of stereotactic needle interventions in small animals.

  5. A Novel Quantitative Computed Tomographic Analysis Suggests How Sirolimus Stabilizes Progressive Air Trapping in Lymphangioleiomyomatosis.

    Science.gov (United States)

    Argula, Rahul G; Kokosi, Maria; Lo, Pechin; Kim, Hyun J; Ravenel, James G; Meyer, Cristopher; Goldin, Jonathan; Lee, Hye-Seung; Strange, Charlie; McCormack, Francis X

    2016-03-01

    The Multicenter International Lymphangioleiomyomatosis Efficacy and Safety of Sirolimus (MILES) trial demonstrated that sirolimus stabilized lung function and improved measures of functional performance and quality of life in patients with lymphangioleiomyomatosis. The physiologic mechanisms of these beneficial actions of sirolimus are incompletely understood. To prospectively determine the longitudinal computed tomographic lung imaging correlates of lung function change in MILES patients treated with placebo or sirolimus. We determined the baseline to 12-month change in computed tomographic image-derived lung volumes and the volume of the lung occupied by cysts in the 31 MILES participants (17 in sirolimus group, 14 in placebo group) with baseline and 12-month scans. There was a trend toward an increase in median expiratory cyst volume percentage in the placebo group and a reduction in the sirolimus group (+2.68% vs. +0.97%, respectively; P = 0.10). The computed tomographic image-derived residual volume and the ratio of residual volume to total lung capacity increased more in the placebo group than in the sirolimus group (+214.4 ml vs. +2.9 ml [P = 0.054] and +0.05 ml vs. -0.01 ml [P = 0.0498], respectively). A Markov transition chain analysis of respiratory cycle cyst volume changes revealed greater dynamic variation in the sirolimus group than in the placebo group at the 12-month time point. Collectively, these data suggest that sirolimus attenuates progressive gas trapping in lymphangioleiomyomatosis, consistent with a beneficial effect of the drug on airflow obstruction. We speculate that a reduction in lymphangioleiomyomatosis cell burden around small airways and cyst walls alleviates progressive airflow limitation and facilitates cyst emptying.

  6. Image-guided microneurosurgical management of small cerebral arteriovenous malformations: the value of navigated computed tomographic angiography

    International Nuclear Information System (INIS)

    Coenen, V.A.; Reinges, M.H.T.; Gilsbach, J.M.; Rohde, V.; Dammert, S.; Mull, M.

    2005-01-01

    In small arteriovenous malformations (AVM) with large hematomas, surgery remains the main therapeutic option. However, intraoperative identification of the AVM, feeders, and draining veins could be difficult in the environment of substantial intracerebral blood. In those selected cases, we use navigated computed tomographic angiography (CTA) for the microneurosurgical management. It is our objective to report our initial experiences. Prior to operation a conventional CTA with superficial skin fiducials placed on a patient's head was acquired for diagnostic and neuronavigation purposes. Image data were transferred to a neuronavigation device with integrated volume rendering capacities which allows a three-dimensional reconstruction of the vascular tree and the AVM to be created. In all patients the AVM was removed successfully after having been localized with CTA-based neuronavigation. Navigated CTA is helpful for the operative management of small AVMs with large hematomas. The technique allows feeding arteries to be distinguished from draining veins thereby allowing the nidus of the AVM to be identified despite the presence of substantial intracerebral blood. CTA can be easily implemented into commercial neuronavigation systems. (orig.)

  7. Design considerations for a time-resolved tomographic diagnostic at DARHT

    International Nuclear Information System (INIS)

    Morris I. Kaufman, Daniel Frayer, Wendi Dreesen, Douglas Johnson, Alfred Meidinger

    2006-01-01

    An instrument has been developed to acquire time-resolved tomographic data from the electron beam at the DARHT [Dual-Axis Radiographic Hydrodynamic Test] facility at Los Alamos National Laboratory. The instrument contains four optical lines of sight that view a single tilted object. The lens design optically integrates along one optical axis for each line of sight. These images are relayed via fiber optic arrays to streak cameras, and the recorded streaks are used to reconstruct the original two-dimensional data. Installation of this instrument into the facility requires automation of both the optomechanical adjustments and calibration of the instrument in a constrained space. Additional design considerations include compound tilts on the object and image planes

  8. Image guidance doses delivered during radiotherapy: Quantification, management, and reduction: Report of the AAPM Therapy Physics Committee Task Group 180.

    Science.gov (United States)

    Ding, George X; Alaei, Parham; Curran, Bruce; Flynn, Ryan; Gossman, Michael; Mackie, T Rock; Miften, Moyed; Morin, Richard; Xu, X George; Zhu, Timothy C

    2018-05-01

    With radiotherapy having entered the era of image guidance, or image-guided radiation therapy (IGRT), imaging procedures are routinely performed for patient positioning and target localization. The imaging dose delivered may result in excessive dose to sensitive organs and potentially increase the chance of secondary cancers and, therefore, needs to be managed. This task group was charged with: a) providing an overview on imaging dose, including megavoltage electronic portal imaging (MV EPI), kilovoltage digital radiography (kV DR), Tomotherapy MV-CT, megavoltage cone-beam CT (MV-CBCT) and kilovoltage cone-beam CT (kV-CBCT), and b) providing general guidelines for commissioning dose calculation methods and managing imaging dose to patients. We briefly review the dose to radiotherapy (RT) patients resulting from different image guidance procedures and list typical organ doses resulting from MV and kV image acquisition procedures. We provide recommendations for managing the imaging dose, including different methods for its calculation, and techniques for reducing it. The recommended threshold beyond which imaging dose should be considered in the treatment planning process is 5% of the therapeutic target dose. Although the imaging dose resulting from current kV acquisition procedures is generally below this threshold, the ALARA principle should always be applied in practice. Medical physicists should make radiation oncologists aware of the imaging doses delivered to patients under their care. Balancing ALARA with the requirement for effective target localization requires that imaging dose be managed based on the consideration of weighing risks and benefits to the patient. © 2018 American Association of Physicists in Medicine.

  9. A system dedicated to the viewing and handling of tomographic images obtained by magnetic resonance; Um sistema dedicado a visualizacao e manipulacao de imagens tomograficas obtidas por ressonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Slaets, Joan F.W.; Almeida, Lirio O.B. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica; Traina, Agma J.M. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Ciencias Matematicas

    1993-12-31

    The present work describes the development of a dedicated system to be used in visualization and manipulation of a MR images. The graphics environment as well as the tool kit were developed for the dedicated TMS34010 based hardware. The developed software offers a compact kernel with primitives to support the creation and manipulation windows and menus directly in `C` language. This work is fundamental for the implementation of a user friendly interface build to operate and visualize tomographic images. This tools are essential for the selection an archiving of images planes as used in clinical applications. (author) 9 refs., 2 figs., 1 photo; e-mail: jan, agma and lirio at uspfsc.ifqsc..usp.ansp.br

  10. A system dedicated to the viewing and handling of tomographic images obtained by magnetic resonance; Um sistema dedicado a visualizacao e manipulacao de imagens tomograficas obtidas por ressonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Slaets, Joan F.W.; Almeida, Lirio O.B. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica; Traina, Agma J.M. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Ciencias Matematicas

    1992-12-31

    The present work describes the development of a dedicated system to be used in visualization and manipulation of a MR images. The graphics environment as well as the tool kit were developed for the dedicated TMS34010 based hardware. The developed software offers a compact kernel with primitives to support the creation and manipulation windows and menus directly in `C` language. This work is fundamental for the implementation of a user friendly interface build to operate and visualize tomographic images. This tools are essential for the selection an archiving of images planes as used in clinical applications. (author) 9 refs., 2 figs., 1 photo; e-mail: jan, agma and lirio at uspfsc.ifqsc..usp.ansp.br

  11. Discrete tomographic reconstruction of 2D polycrystal orientation maps from X-ray diffraction projections using Gibbs priors

    DEFF Research Database (Denmark)

    Rodek, L.; Knudsen, E.; Poulsen, H.F.

    2005-01-01

    discrete tomographic algorithm, applying image-modelling Gibbs priors and a homogeneity condition. The optimization of the objective function is accomplished via the Gibbs Sampler in conjunction with simulated annealing. In order to express the structure of the orientation map, the similarity...

  12. Iodine-123 N-methyl-4-iododexetimide: a new radioligand for single-photon emission tomographic imaging of myocardial muscarinic receptors

    International Nuclear Information System (INIS)

    Hicks, R.J.; Kassiou, M.; Eu, P.; Katsifis, A.G.; Garra, M.; Power, J.; Najdovski, L.; Lambrecht, R.M.

    1995-01-01

    Cardiac muscarinic receptor ligands suitable for positron emission tomography have previously been characterised. Attempts to develop radioligands of these receptors suitable for single-photon emission tomographic (SPET) imaging have not been successful due to high lung retention and high non-specific binding of previously investigated potential tracers. The purpose of this study was to evaluate the biodistribution and in vivo imaging characteristics of a new radiopharmaceutical, [ 123 I]N-methyl-4-iododexetimide. Biodistribution studies performed in rats showed high cardiac uptake (2.4% ID/g) 10 min after injection with a heart to lung activity ratio of 5:1. Specificity and stereoselectivity of cardiac binding were demonstrated using blocking experiments in rats. Dynamic imaging studies in anaesthetised greyhounds demonstrated rapid and high myocardial uptake and low lung binding with stable heart to lung activity ratios of >2.5:1 between 10 and 30 min, making SPET imaging feasible. Administration of an excess of an unlabelled muscarinic antagonist, methyl-quinuclidinyl benzylate rapidly displaced myocardial activity to background levels and the pharmacologically inactive enantiomer, [ 123 I]N-methyl-4-iodolevetimide, had no detectable cardiac uptake, indicating specific and stereoselective muscarinic receptor binding. SPET revealed higher activity in the inferior than in the anterior wall, this being consistent with previously described regional variation of cardiac parasympathetic innervation. [ 123 I]N-methyl-4-iododexetimide shows promise as an imaging agent for muscarinic receptor distribution in the heart and may be helpful in evaluating diverse cardiac diseases associated with altered muscarinic receptor function, including heart failure and diabetic heart disease. (orig.)

  13. Computed tomographic evaluation of the altered pancreas in dog and cat

    International Nuclear Information System (INIS)

    Posch, B.

    2002-11-01

    Eighteen dogs and 12 cats of varying breed, age and sex underwent a computed tomographic study of the pancreas. Length, diameter and density of each lobe of the pancreas were measured. Further, the gained results were compared to the information established by the clinical examination, sonography, haematology and histology. Contrast CT improved evaluation of the pancreas in all cases of normal life controls. CT criteria such as changes in size, density, delimitation of the pancreas and the peripancreatic structures were analyzed. Increased pancreatic size was seen in inflammatory as well as in neoplastic diseases. There were no reliable computed tomographic criteria to differentiate pancreatic neoplasia from inflammation without peripancreatic findings. Ultrasonography proved to be a good screening method in this study: sonographic and computed tomographic results correlated in all cases with the exception of 5 cases. In contrast to ultrasonography CT could differentiate normal pancreas from pancreas atrophy. Computed tomography was superior to sonography in determining the full extent of pancreatic and peripancreatic signs due to the good overview and overall image of the abdominal structures. Serum chemistry of a- amylase and lipase were obtained in 28 animals. Assays of serum lipase and a- amylase activities were only able to detect acute pancreatitis in half of the canine cases. Despite morphological alterations detected with the help of sonography or CT, there were no significant increases in a- amylase and lipase in cats. Following computed tomography the pancreas of 10 animals was examined pathohistologically. With the exception of 2 cases the computed tomographic results correlated with the pathohistological findings. In conclusion, computed tomography (CT) proved to be a valuable method to evaluate the localization, the full extent and the seriousness of pancreatic lesions. (author)

  14. Health Service use of ionising radiations: Guidance

    International Nuclear Information System (INIS)

    1995-01-01

    This booklet gives outline guidance on the use of ionising radiations in the Health Service in the United Kingdom. Extensive reference is made to documents where more detailed information may be found. The guidance covers general advice on the medical use of ionising radiations, statutory requirements, and guidance on selected Health Service issues such as patient identification procedures, information management systems, deviations from prescribed radiation dose, imaging and radiotherapy. (57 references) (U.K.)

  15. Precision of quantum tomographic detection of radiation

    Energy Technology Data Exchange (ETDEWEB)

    D' Ariano, G.M. (Dipartimento di Fisica ' ' Alessandro Volta' ' , Via A. Bassi 6, I-27100, Pavia (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Via A. Bassi 6, I-27100, Pavia (Italy)); Macchiavello, Chiara (Dipartimento di Fisica ' ' Alessandro Volta' ' , Via A. Bassi 6, I-27100, Pavia (Italy)); Paris, M.G.A. (Dipartimento di Fisica ' ' Alessandro Volta' ' , Via A. Bassi 6, I-27100, Pavia (Italy))

    1994-11-21

    Homodyne tomography provides an experimental technique for reconstructing the density matrix of the radiation field. Here we analyze the tomographic precision in recovering observables like the photon number, the quadrature, and the phase. We show that tomographic reconstruction, despite providing a complete characterization of the state of the field, is generally much less efficient than conventional detection techniques. ((orig.))

  16. Precision of quantum tomographic detection of radiation

    International Nuclear Information System (INIS)

    D'Ariano, G.M.; Macchiavello, Chiara; Paris, M.G.A.

    1994-01-01

    Homodyne tomography provides an experimental technique for reconstructing the density matrix of the radiation field. Here we analyze the tomographic precision in recovering observables like the photon number, the quadrature, and the phase. We show that tomographic reconstruction, despite providing a complete characterization of the state of the field, is generally much less efficient than conventional detection techniques. ((orig.))

  17. Tomographic anthropomorphic models. Pt. 1

    International Nuclear Information System (INIS)

    Veit, R.; Zankl, M.; Petoussi, N.; Mannweiler, E.; Drexler, G.; Williams, G.

    1989-01-01

    The first generation of heterogenoeous anthropomorphic mathematical models to be used in dose calculations was the MIRD-5 adult phantom, followed by the pediatric MIRD-type phantoms and by the GSF sex-specific phantoms ADAM and EVA. A new generation of realistic anthropomorphic models is now introduced. The organs and tissues of these models consist of a well defined number of volume elements (voxels), derived from computer tomographic (CT) data; consequently, these models were named voxel or tomographic models. So far two voxel models of real patients are available: one of an 8 week old baby and of a 7 year old child. For simplicity, the model of the baby will be referred to as BABY and that of the child as CHILD. In chapter 1 a brief literature review is given on the existing mathematical models and their applications. The reasons that lead to the construction of the new CT models is discussed. In chapter 2 the technique is described which allows to convert any physical object into computer files to be used for dose calculations. The technique which produces three dimensional reconstructions of high resolution is discussed. In chapter 3 the main characteristics of the models of the baby and child are given. Tables of organ masses and volumes are presented together with three dimensional images of some organs and tissues. A special mention is given to the assessment of bone marrow distribution. Chapter 4 gives a short description of the Monte Carlo code used in conjunction with the models to calculate organ and tissue doses resulting from photon exposures. Some technical details concerning the computer files which describe the models are also given. (orig./HP)

  18. Three-dimensional multislice spiral computed tomographic angiography: a potentially useful tool for safer free tissue transfer to complicated regions

    DEFF Research Database (Denmark)

    Demirtas, Yener; Cifci, Mehmet; Kelahmetoglu, Osman

    2009-01-01

    Three-dimensional multislice spiral computed tomographic angiography (3D-MSCTA) is a minimally invasive method of vascular mapping. The aim of this study was to evaluate the clinical usefulness of this imaging technique in delineating the recipient vessels for safer free tissue transfer to compli......Three-dimensional multislice spiral computed tomographic angiography (3D-MSCTA) is a minimally invasive method of vascular mapping. The aim of this study was to evaluate the clinical usefulness of this imaging technique in delineating the recipient vessels for safer free tissue transfer...... be kept in mind, especially inthe patients with peripheral vascular disease. 3D-MSCTA has the potential to replace digital subtraction angiography for planning of microvascular reconstructions and newer devices with higher resolutions will probably increase the reliability of this technique. (c) 2009...

  19. A multimodal imaging framework for enhanced robot-assisted partial nephrectomy guidance

    Science.gov (United States)

    Halter, Ryan J.; Wu, Xiaotian; Hartov, Alex; Seigne, John; Khan, Shadab

    2015-03-01

    Robot-assisted laparoscopic partial nephrectomies (RALPN) are performed to treat patients with locally confined renal carcinoma. There are well-documented benefits to performing partial (opposed to radical) kidney resections and to using robot-assisted laparoscopic (opposed to open) approaches. However, there are challenges in identifying tumor margins and critical benign structures including blood vessels and collecting systems during current RALPN procedures. The primary objective of this effort is to couple multiple image and data streams together to augment visual information currently provided to surgeons performing RALPN and ultimately ensure complete tumor resection and minimal damage to functional structures (i.e. renal vasculature and collecting systems). To meet this challenge we have developed a framework and performed initial feasibility experiments to couple pre-operative high-resolution anatomic images with intraoperative MRI, ultrasound (US) and optical-based surface mapping and kidney tracking. With these registered images and data streams, we aim to overlay the high-resolution contrast-enhanced anatomic (CT or MR) images onto the surgeon's view screen for enhanced guidance. To date we have integrated the following components of our framework: 1) a method for tracking an intraoperative US probe to extract the kidney surface and a set of embedded kidney markers, 2) a method for co-registering intraoperative US scans with pre-operative MR scans, and 3) a method for deforming pre-op scans to match intraoperative scans. These components have been evaluated through phantom studies to demonstrate protocol feasibility.

  20. Deformable 3D–2D registration for CT and its application to low dose tomographic fluoroscopy

    International Nuclear Information System (INIS)

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-01-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D–3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D–2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D–3D registration method. The comparison is done for a range of 4–60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D–3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness

  1. Computer tomographs

    International Nuclear Information System (INIS)

    Niedzwiedzki, M.

    1982-01-01

    Physical foundations and the developments in the transmission and emission computer tomography are presented. On the basis of the available literature and private communications a comparison is made of the various transmission tomographs. A new technique of computer emission tomography ECT, unknown in Poland, is described. The evaluation of two methods of ECT, namely those of positron and single photon emission tomography is made. (author)

  2. Segmentation Toolbox for Tomographic Image Data

    DEFF Research Database (Denmark)

    Einarsdottir, Hildur

    , techniques to automatically analyze such data becomes ever more important. Most segmentation methods for large datasets, such as CT images, deal with simple thresholding techniques, where intensity values cut offs are predetermined and hard coded. For data where the intensity difference is not sufficient......Motivation: Image acquisition has vastly improved over the past years, introducing techniques such as X-ray computed tomography (CT). CT images provide the means to probe a sample non-invasively to investigate its inner structure. Given the wide usage of this technique and massive data amounts......, and partial volume voxels occur frequently, thresholding methods do not suffice and more advanced methods are required. Contribution: To meet these requirements a toolbox has been developed, combining well known methods within the image analysis field. The toolbox includes cluster-based methods...

  3. Computed tomographic study of 50 patients with hypodense hepatic injuries in childhood; Estudo de 50 casos por tomografia computadorizada de lesoes hipodensas hepaticas fundamentais na infancia

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Ines Minniti Rodrigues; Alvares, Beatriz Regina; Baracat, Jamal; Martins, Daniel Lahan [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Ciencias Medicas. Dept. de Radiologia]. E-mail: iminniti@fcm.unicamp.br; Pereira, Ricardo Minniti Rodrigues [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Ciencias Medicas

    2006-03-15

    Objective: To describe the different tomographic findings in hypodense hepatic lesions in children and its differential diagnosis. Materials and methods: computed tomographic studies were obtained from 50 patients (age range: 0-16 years) with low-density liver lesions previously diagnosed by ultrasound. Images were made before and after administration of intravenous contrast medium. Image findings were analyzed and afterwards correlated with anatomopathological diagnosis. Results: forty-seven of 50 cases were confirmed, 30 by anatomopathological diagnosis. Most of then were benign lesions, hemangioma in 20%. Such lesions presented a homogeneous contrast absorption, mainly at the delayed phase, differing from malignant lesions. Metastasis was the most frequently found malignant lesion (18%). Conclusion: computed tomographic study is of great value in complementing the diagnosis of hypodense hepatic lesions in children, and must follow ultrasound diagnosis as a routine procedure. (author)

  4. The impact of different imaging modalities of 67Ga scintigraphy on the image quality and the ability in detection of lesions

    International Nuclear Information System (INIS)

    Liu Xiuqin; Li Wenchan; Zhang Jianfei; Yao Zhiming

    2009-01-01

    Objective: 67 Ga scintigraphy is an important method in detection of active sarcoidosis. The aim of this research was to study the influence of planar and tomography. with and without CT attenuation correction (AC and NAC), on 67 Ga images on the image quality and the ability in detection of lesions. Methods: Thirty one patients (13 male, 18 female, age range: 33-87 years)with sarcoidosis underwent 67 Ga planar and tomographic scans. AC and NAC.The imaging quality and the ability in detection of hyper-radioactive lymph nodes in lung hilar and mediastinal(1esion) among the planar, AC and NAC images were compared. The paired t-test and χ 2 -test were used for data analysis with SPSS 10.0 software. Results: From planar, NAC to AC, the image quality was better and better in proper order (χ 2 = 25.88, P 67 Ga tomographic scintigraphy can impmve the ability in detection of hyperradioactive lung hilar and mediastinal lymph nodes compared with planar image does. CT AC for 67 Ga tomography can improve the tomographic imaging quality. (authors)

  5. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are given of a tomographic scanning apparatus, with particular reference to the means of adjusting the apparent gain of the signal processing means for receiving output signals from the detectors, to compensate for drift in the gain characteristics, including means for passing a reference signal. (U.K.)

  6. ULTRASOUND AND COMPUTED TOMOGRAPHIC DIAGNOSIS OF OPTIC NERVE TUMORS

    Directory of Open Access Journals (Sweden)

    S. V. Saakyan

    2012-01-01

    Full Text Available A comprehensive examination was made in 93 patients, including 18 children, with tumors of the optic nerve (ON. Duplex ultrasound scanning was performed in 39 patients, of them there were 11 patients with ON gliomas and 28 with ON meningiomas. The specific computed tomographic and echographic signs of ON glioma and meningiomas were detected. The studies have shown that duplex ultrasound scanning and structural computed tomography of orbital sockets are highly informative complementary imaging procedures for ON tumors, which permits one to make their correct diagnosis, to specify surgical volume, and to plan adequate treatment.

  7. Computed tomographic guidance stereotaxis in the management of intracranial mass lesions

    International Nuclear Information System (INIS)

    Apuzzo, M.L.; Sabshin, J.K.

    1983-01-01

    A prototype Brown-Roberts-Welles stereotactic instrument has been used as both a diagnostic and a therapeutic surgical adjunct in cases of intracranial mass lesions. Eighty-three procedures (142 point placements) required computerized guidance stereotaxy. The unit accomplished point intracranial access with an accuracy of greater than 1 mm. Pathological processes included a variety of neoplasms (56 cases), strokes (7 cases), and infections (20 cases) affecting deep regions of the cerebral hemispheres, the ventricular system, the cerebellum, and the rostral brain stem. Procedures were undertaken with the patient under local anesthesia for biopsy (300 point specimens), culture, evacuation, aspiration, endoscopic excision, and implantation of radioisotopes. The techniques and instrumentation for each of these procedures are described. Procedural objectives were satisfactorily accomplished with no mortality and an overall complication rate of 4%. Recovery of tissue specific to establish a histological diagnosis or the etiological factors related to each disease process was realized in 94% of the cases. These results were obtained with scanner utilization times averaging 15 minutes and procedurally related patient recovery periods of less than 4 hours. The value and adaptability of the instrumentation and techniques are illustrated, and potential future applications are discussed

  8. Tomographic anthropomorphic models. Pt. 2. Organ doses from computed tomographic examinations in paediatric radiology

    International Nuclear Information System (INIS)

    Zankl, M.; Panzer, W.; Drexler, G.

    1993-11-01

    This report provides a catalogue of organ dose conversion factors resulting from computed tomographic (CT) examinations of children. Two radiation qualities and two exposure geometries were simulated as well as the use of asymmetrical beams. The use of further beam shaping devices was not considered. The organ dose conversion factors are applicable to babies at the age of ca. 2 months and to children between 5 and 7 years but can be used for other ages as well with the appropriate adjustments. For the calculations, the patients were represented by the GSF tomographic anthropomorphic models BABY and CHILD. The radiation transport in the body was simulated using a Monte Carlo method. The doses are presented as conversion factors of mean organ doses per air kerma free in air on the axis of rotation. Mean organ dose conversion factors are given per organ and per scanned body section of 1 cm height. The mean dose to an organ resulting from a particular CT examination can be estimated by summing up the contributions to the organ dose from all relevant sections. To facilitate the selection of the appropriate sections, a table is given which relates the tomographic models' coordinates to certain anatomical landmarks in the human body. (orig.)

  9. SU-D-BRF-05: A Novel System to Provide Real-Time Image-Guidance for Intrauterine Tandem Insertion and Placement

    Energy Technology Data Exchange (ETDEWEB)

    Price, M; Fontenot, J [pF Biomedical Solutions LLC, Baton Rouge, LA (United States)

    2014-06-01

    Purpose: To develop a system that provides real-time image-guidance for intrauterine tandem insertion and placement for brachytherapy. Methods: The conceptualized system consists of an intrauterine tandem with a transparent, lensed tip, a flexible miniature fiber optic scope, light source and interface for CCD coupling. The tandem tip was designed to act as a lens providing a wide field-of-view (FOV) with minimal image distortion and focus length appropriate for the application. The system is designed so that once inserted, the image-guidance component of the system can be removed and brachytherapy can be administered without interfering with source transport or disturbing tandem placement. Proof-of-principle studies were conducted to assess the conceptualized system's (1) lens functionality (clarity, focus and FOV) (2) and ability to visualize the cervical os of a female placed in the lithotomy position. Results: A prototype of this device was constructed using a commercial tandem modified to incorporate a transparent tip that internally coupled with a 1.9mm diameter fiber optic cable. The 900mm-long cable terminated at an interface that provided illumination as well as facilitated visualization of patient anatomy on a computer. The system provided a 23mm FOV with a focal length of 1cm and provided clear visualization of the cervix, cervical fornix and cervical os. The optical components of the system are easily removed without perturbing the position of a tandem placed in a common fixation clamp. Conclusion: Clinicians frequently encounter difficulty inserting an intrauterine tandem through the cervical os, circumventing fibrotic tissue or masses within the uterus, and positioning the tandem without perforating the uterus. To mitigate these challenges, we have designed and conducted proof-of- principle studies to discern the utility of a prototype device that provides real-time image-guidance for intrauterine tandem placement using fiber optic components.

  10. Computed tomographic and cross-sectional anatomy of the normal pacu (Colossoma macroponum).

    Science.gov (United States)

    Carr, Alaina; Weber, E P Scott; Murphy, Chris J; Zwingenberger, Alison

    2014-03-01

    The purpose of this study was to compare and define the normal cross-sectional gross and computed tomographic (CT) anatomy for a species of boney fish to better gain insight into the use of advanced diagnostic imaging for future clinical cases. The pacu (Colossoma macropomum) was used because of its widespread presence in the aquarium trade, its relatively large body size, and its importance in the research and aquaculture settings. Transverse 0.6-mm CT images of three cadaver fish were obtained and compared to corresponding frozen cross sections of the fish. Relevant anatomic structures were identified and labeled at each level; the Hounsfield unit density of major organs was established. The images presented good anatomic detail and provide a reference for future research and clinical investigation.

  11. Optical Computed-Tomographic Microscope for Three-Dimensional Quantitative Histology

    Directory of Open Access Journals (Sweden)

    Ravil Chamgoulov

    2004-01-01

    Full Text Available A novel optical computed‐tomographic microscope has been developed allowing quantitative three‐dimensional (3D imaging and analysis of fixed pathological material. Rather than a conventional two‐dimensional (2D image, the instrument produces a 3D representation of fixed absorption‐stained material, from which quantitative histopathological features can be measured more accurately. The accurate quantification of these features is critically important in disease diagnosis and the clinical classification of cancer. The system consists of two high NA objective lenses, a light source, a digital spatial light modulator (DMD, by Texas Instrument, an x–y stage, and a CCD detector. The DMD, positioned at the back pupil‐plane of the illumination objective, is employed to illuminate the specimen with parallel rays at any desired angle. The system uses a modification of the convolution backprojection algorithm for reconstruction. In contrast to fluorescent images acquired by a confocal microscope, this instrument produces 3D images of absorption stained material. Microscopic 3D volume reconstructions of absorption‐stained cells have been demonstrated. Reconstructed 3D images of individual cells and tissue can be cut virtually with the distance between the axial slices less than 0.5 μm.

  12. Accuracy of Ultrasound-Based Image Guidance for Daily Positioning of the Upper Abdomen: An Online Comparison With Cone Beam CT

    International Nuclear Information System (INIS)

    Boda-Heggemann, Judit; Mennemeyer, Philipp; Wertz, Hansjoerg; Riesenacker, Nadja; Kuepper, Beate; Lohr, Frank; Wenz, Frederik

    2009-01-01

    Purpose: Image-guided intensity-modulated radiotherapy can improve protection of organs at risk when large abdominal target volumes are irradiated. We estimated the daily positioning accuracy of ultrasound-based image guidance for abdominal target volumes by a direct comparison of daily imaging obtained with cone beam computed tomography (CBCT). Methods and Materials: Daily positioning (n = 83 positionings) of 15 patients was completed by using ultrasound guidance after an initial CBCT was obtained. Residual error after ultrasound was estimated by comparison with a second CBCT. Ultrasound image quality was visually rated using a scale of 1 to 4. Results: Of 15 patients, 7 patients had good sonographic imaging quality, 5 patients had satisfactory sonographic quality, and 3 patients were excluded because of unsatisfactory sonographic quality. When image quality was good, residual errors after ultrasound were -0.1 ± 3.11 mm in the x direction (left-right; group systematic error M = -0.09 mm; standard deviation [SD] of systematic error, Σ = 1.37 mm; SD of the random error, σ = 2.99 mm), 0.93 ± 4.31 mm in the y direction (superior-inferior, M = 1.12 mm; Σ = 2.96 mm; σ = 3.39 mm), and 0.71 ± 3.15 mm in the z direction (anteroposterior; M = 1.01 mm; Σ = 2.46 mm; σ = 2.24 mm). For patients with satisfactory image quality, residual error after ultrasound was -0.6 ± 5.26 mm in the x (M = 0.07 mm; Σ = 5.67 mm; σ = 4.86 mm), 1.76 ± 4.92 mm in the y (M = 3.54 mm; Σ = 4.1 mm; σ = 5.29 mm), and 1.19 ± 4.75 mm in the z (M = 0.82 mm; Σ = 2.86 mm; σ = 3.05 mm) directions. Conclusions: In patients from whom good sonographic image quality could be obtained, ultrasound improved daily positioning accuracy. In the case of satisfactory image quality, ultrasound guidance improved accuracy compared to that of skin marks only minimally. If sonographic image quality was unsatisfactory, daily CBCT scanning improved treatment accuracy distinctly over that of ultrasound. Use of

  13. Voxel-based model construction from colored tomographic images; Construcao de simuladores baseados em elementos de volume a partir de imagens tomograficas coloridas

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Eduardo Cesar de Miranda

    2002-07-01

    This work presents a new approach in the construction of voxel-based phantoms that was implemented to simplify the segmentation process of organs and tissues reducing the time used in this procedure. The segmentation process is performed by painting tomographic images and attributing a different color for each organ or tissue. A voxel-based head and neck phantom was built using this new approach. The way as the data are stored allows an increasing in the performance of the radiation transport code. The program that calculates the radiation transport also works with image files. This capability allows image reconstruction showing isodose areas, under several points of view, increasing the information to the user. Virtual X-ray photographs can also be obtained allowing that studies could be accomplished looking for the radiographic techniques optimization assessing, at the same time, the doses in organs and tissues. The accuracy of the program here presented, called MCvoxEL, that implements this new approach, was tested by comparison to results from two modern and well-supported Monte Carlo codes. Dose conversion factors for parallel X-ray exposure were also calculated. (author)

  14. Design and evaluation of HEADTOME-IV, a whole-body positron emission tomograph

    International Nuclear Information System (INIS)

    Iida, H.; Miura, S.; Kanno, I.; Murakami, M.; Takahashi, K.; Uemura, K.

    1989-01-01

    A whole body positron emission tomograph HEADTOME-IV has been developed, and its physical performances were investigated. The in-plane spatial resolution of 4.5 mm was realized with stationary-sampling at the center of the field-of-view. The axial slice thickness was 9.5 and 9.0-mm for direct and cross planes, respectively. By moving the gantry framework axially, transaxial images of 14 or 21 slices are obtained quasi-simultaneously. The realtime-operation large-scale cache memory system was effective to realize realtime corrections for deadtime and radionuclide decay, and realtime weighted integration for the purpose of a rapid calculation of rate-constant images

  15. Percutaneous Transhepatic Drainage of Inaccessible Abdominal Abscesses Following Abdominal Surgery Under Real-Time CT-Fluoroscopic Guidance

    International Nuclear Information System (INIS)

    Yamakado, Koichiro; Takaki, Haruyuki; Nakatsuka, Atsuhiro; Kashima, Masataka; Uraki, Junji; Yamanaka, Takashi; Takeda, Kan

    2010-01-01

    This study evaluated the safety, feasibility, and clinical utility of transhepatic drainage of inaccessible abdominal abscesses retrospectively under real-time computed tomographic (CT) guidance. For abdominal abscesses, 12 consecutive patients received percutaneous transhepatic drainage. Abscesses were considered inaccessible using the usual access route because they were surrounded by the liver and other organs. The maximum diameters of abscesses were 4.6-9.5 cm (mean, 6.7 ± 1.4 cm). An 8-Fr catheter was advanced into the abscess cavity through the liver parenchyma using real-time CT fluoroscopic guidance. Safety, feasibility, procedure time, and clinical utility were evaluated. Drainage catheters were placed with no complications in abscess cavities through the liver parenchyma in all patients. The mean procedure time was 18.8 ± 9.2 min (range, 12-41 min). All abscesses were drained. They shrank immediately after catheter placement. In conclusions, this transhepatic approach under real-time CT fluoroscopic guidance is a safe, feasible, and useful technique for use of drainage of inaccessible abdominal abscesses.

  16. Tomographic findings of lobar consolidation in primary pulmonary tuberculosis; Aspectos tomograficos da consolidacao lobar na tuberculose pulmonar primaria

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Bruno Alberto Falcao [Hopital Europeen Georges Pompidou, Paris (France); Macedo, Solange Goncalves David de [Hospital Municipal Jesus, Rio de Janeiro, RJ (Brazil). Setor de Pneumologia; Nogueira, Renata do Amaral [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil). Setor de Pediatria; Castiel, Lola Celeste Pantoja [Clinica Radiologica Dr. Samuel Castiel, Porto Velho, RO (Brazil); Penna, Claudia Renata Rezende [Hospital Municipal Jesus, Rio de Janeiro, RJ (Brazil). Servico de Radiologia Pediatrica], e-mail: cr-penna@uol.com.br

    2009-03-15

    Objective: To describe tomographic findings of lobar consolidation as early manifestation of primary pulmonary tuberculosis. Materials and methods: The present study was developed at Hospital Municipal Jesus, Rio de Janeiro, RJ, Brazil, in the period between 2002 and 2006, retrospectively evaluating tomographic findings in four children aged from 3 to 14 months with lobar consolidation as an early manifestation of primary pulmonary tuberculosis. Results: The most frequently found radiological pattern was lobar consolidation with calcifications, cavitation and intermingle necrotic areas, associated with bulging fissure. Signs of bronchogenic dissemination and lymph node enlargement were observed in all of the four children. Consolidation with a pseudotumor aspect and masslike effect was observed in one case. Conclusion: The cases included in the present study have demonstrated that primary pulmonary tuberculosis manifested as lobar consolidation presents typical tomographic images such as cavitation, hypodense areas and calcifications intermingled with consolidation. The association with lymph node enlargement with central necrosis and signs of bronchogenic dissemination reinforce the diagnosis of tuberculosis. (author)

  17. Computed tomographic-guided iodine-125 interstitial implants for malignant thoracic tumors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qiming [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China); The Department of Radiology, Second Affiliated Hospital of Fujian Medical University, 34 Zhongshan Bei Road, Quanzhou 362000 (China); Chen, Jin; Chen, Qunlin [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China); Lai, Qingquan; Cai, Siqing [The Department of Radiology, Second Affiliated Hospital of Fujian Medical University, 34 Zhongshan Bei Road, Quanzhou 362000 (China); Luo, Kaidong [The Department of Radiology, Longyan Hosptial of Traditional Chinese Medical, 59 Longteng Middle Road, Longyan 364000 (China); Lin, Zhengyu, E-mail: linsinlan@yahoo.com.cn [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China)

    2013-11-01

    Purpose: To evaluate the feasibility and efficacy of percutaneous interstitial brachytherapy using iodine-125 ({sup 125}I) radioactive seeds under computed tomographic (CT) guidance for malignant thoracic tumors. Materials and methods: Forty-one patients (34 males, 7 females; 18–90 years; mean, 63.7 years) with 77 lesions (3 in the mediastinum, 7 in the chest wall, 67 in the lung) underwent percutaneous interstitial implantation of {sup 125}I radioactive seeds under CT guidance. A treatment planning system (TPS) was employed to calculate the number and distribution of seeds preoperatively. An 18-G needle was inserted into the lesions under CT guidance and send the seeds according to TPS. Two patients with mediastinal lesions undergoing seed implantation received an artificial pneumothorax. One patient with lung carcinoma adjacent to the anterior mediastinum underwent seed implantation through the sternum. Follow-up CT was done every 2 months postoperatively. Results: The procedure was successful in all patients. No major procedure-associated death occurred. The mean duration of follow-up was 19.4 ± 1.3 months (3–49 months). A complete response (CR) was seen in 49 lesions (63.6%), partial response (PR) in 9 lesions (11.7%), stable disease (SD) in 12 lesions (12.8%), and progressive disease (PD) in 7 lesions (7.4%). The overall response rate (CR + PR) was 75.3%; the local control rate (CR + PR + SD) was 90.9%. The 1-, 2- and 3-year progression-free rates for local tumors were 91%, 88% and 88%, respectively. The 1-, 2- and 3-year survival rates were 87%, 74% and 68%, respectively. Conclusion: Implantation of CT-guided {sup 125}I seeds is feasible and effective for patients with malignant thoracic tumors.

  18. An image guidance system for positioning robotic cochlear implant insertion tools

    Science.gov (United States)

    Bruns, Trevor L.; Webster, Robert J.

    2017-03-01

    Cochlear implants must be inserted carefully to avoid damaging the delicate anatomical structures of the inner ear. This has motivated several approaches to improve the safety and efficacy of electrode array insertion by automating the process with specialized robotic or manual insertion tools. When such tools are used, they must be positioned at the entry point to the cochlea and aligned with the desired entry vector. This paper presents an image guidance system capable of accurately positioning a cochlear implant insertion tool. An optical tracking system localizes the insertion tool in physical space while a graphical user interface incorporates this with patient- specific anatomical data to provide error information to the surgeon in real-time. Guided by this interface, novice users successfully aligned the tool with an mean accuracy of 0.31 mm.

  19. Tomographic Imaging of the Peru Subduction Zone beneath the Altiplano and Implications for Andean Tectonics

    Science.gov (United States)

    Davis, P. M.; Foote, E. J.; Stubailo, I.; Phillips, K. E.; Clayton, R. W.; Skinner, S.; Audin, L.; Tavera, H.; Dominguez Ramirez, L. A.; Lukac, M. L.

    2010-12-01

    This work describes preliminary tomography results from the Peru Seismic Experiment (PERUSE) a 100 station broadband seismic network installed in Peru. The network consists a linear array of broadband seismic stations that was installed mid-2008 that runs from the Peruvian coast near Mollendo to Lake Titicaca. A second line was added in late 2009 between Lake Titicaca and Cusco. Teleseismic and local earthquake travel time residuals are being combined in the tomographic inversions. The crust under the Andes is found to be 70-80 km thick decreasing to 30 km near the coast. The morphology of the Moho is consistent with the receiver function images (Phillips et al., 2010; this meeting) and also gravity. Ray tracing through the heterogeneous structure is used to locate earthquakes. However the rapid spatial variation in crustal thickness, possibly some of the most rapid in the world, generates shadow zones when using conventional ray tracing for the tomography. We use asymptotic ray theory that approximates effects from finite frequency kernels to model diffracted waves in these regions. The observation of thickened crust suggests that models that attribute the recent acceleration of the Altiplano uplift to crustal delamination are less likely than those that attribute it to crustal compression.

  20. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The objects of this invention are first to reduce the time required to obtain statistically significant data in trans-axial tomographic radioisotope scanning using a scintillation camera. Secondly, to provide a scintillation camera system to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a known radiation source without sacrificing spatial resolution. Thirdly to reduce the scanning time without loss of image clarity. The system described comprises a scintillation camera detector, means for moving this in orbit about a cranial-caudal axis relative to a patient and a collimator having septa defining apertures such that gamma rays perpendicular to the axis are admitted with high spatial resolution, parallel to the axis with low resolution. The septa may be made of strips of lead. Detailed descriptions are given. (U.K.)

  1. Chest Computed Tomographic Image Screening for Cystic Lung Diseases in Patients with Spontaneous Pneumothorax Is Cost Effective.

    Science.gov (United States)

    Gupta, Nishant; Langenderfer, Dale; McCormack, Francis X; Schauer, Daniel P; Eckman, Mark H

    2017-01-01

    Patients without a known history of lung disease presenting with a spontaneous pneumothorax are generally diagnosed as having primary spontaneous pneumothorax. However, occult diffuse cystic lung diseases such as Birt-Hogg-Dubé syndrome (BHD), lymphangioleiomyomatosis (LAM), and pulmonary Langerhans cell histiocytosis (PLCH) can also first present with a spontaneous pneumothorax, and their early identification by high-resolution computed tomographic (HRCT) chest imaging has implications for subsequent management. The objective of our study was to evaluate the cost-effectiveness of HRCT chest imaging to facilitate early diagnosis of LAM, BHD, and PLCH. We constructed a Markov state-transition model to assess the cost-effectiveness of screening HRCT to facilitate early diagnosis of diffuse cystic lung diseases in patients presenting with an apparent primary spontaneous pneumothorax. Baseline data for prevalence of BHD, LAM, and PLCH and rates of recurrent pneumothoraces in each of these diseases were derived from the literature. Costs were extracted from 2014 Medicare data. We compared a strategy of HRCT screening followed by pleurodesis in patients with LAM, BHD, or PLCH versus conventional management with no HRCT screening. In our base case analysis, screening for the presence of BHD, LAM, or PLCH in patients presenting with a spontaneous pneumothorax was cost effective, with a marginal cost-effectiveness ratio of $1,427 per quality-adjusted life-year gained. Sensitivity analysis showed that screening HRCT remained cost effective for diffuse cystic lung diseases prevalence as low as 0.01%. HRCT image screening for BHD, LAM, and PLCH in patients with apparent primary spontaneous pneumothorax is cost effective. Clinicians should consider performing a screening HRCT in patients presenting with apparent primary spontaneous pneumothorax.

  2. HFSB-seeding for large-scale tomographic PIV in wind tunnels

    Science.gov (United States)

    Caridi, Giuseppe Carlo Alp; Ragni, Daniele; Sciacchitano, Andrea; Scarano, Fulvio

    2016-12-01

    A new system for large-scale tomographic particle image velocimetry in low-speed wind tunnels is presented. The system relies upon the use of sub-millimetre helium-filled soap bubbles as flow tracers, which scatter light with intensity several orders of magnitude higher than micron-sized droplets. With respect to a single bubble generator, the system increases the rate of bubbles emission by means of transient accumulation and rapid release. The governing parameters of the system are identified and discussed, namely the bubbles production rate, the accumulation and release times, the size of the bubble injector and its location with respect to the wind tunnel contraction. The relations between the above parameters, the resulting spatial concentration of tracers and measurement of dynamic spatial range are obtained and discussed. Large-scale experiments are carried out in a large low-speed wind tunnel with 2.85 × 2.85 m2 test section, where a vertical axis wind turbine of 1 m diameter is operated. Time-resolved tomographic PIV measurements are taken over a measurement volume of 40 × 20 × 15 cm3, allowing the quantitative analysis of the tip-vortex structure and dynamical evolution.

  3. A tomographic approach to intravenous coronary arteriography

    International Nuclear Information System (INIS)

    Ritman, E.L.; Bove, A.A.

    1986-01-01

    Coronary artery anatomy can be visualized using high speed, volume scanning X-ray CT. A single scan during a bolus injection of contrast medium provides image data for display of all angles of view of the opacified coronary arterial tree. Due to the tomographic nature of volume image data the superposition of contrast filled cardiac chambers, such as would occur in the levophase of an intravenous injection of contrast agent, can be eliminated. Data are presented which support these statements. The Dynamic Spatial Reconstructor (DSR) was used to scan a life-like radiologic phantom of an adult human thorax in which the left atrial and ventricular chambers and the major epicardial coronary arteries were opacified so as to simulate the levophase of an intravenous injection of contrast agent. A catheter filled with diluted contrast agent and with regions of luminal narrowing (i.e. 'stenoses') was advanced along a tract equivalent to a right ventricular catheterization. Ease of visualization of the catheter 'stenoses' and the accuracy with which they can be measured are presented. (Auth.)

  4. Infrared laser transillumination CT imaging system using parallel fiber arrays and optical switches for finger joint imaging

    Science.gov (United States)

    Sasaki, Yoshiaki; Emori, Ryota; Inage, Hiroki; Goto, Masaki; Takahashi, Ryo; Yuasa, Tetsuya; Taniguchi, Hiroshi; Devaraj, Balasigamani; Akatsuka, Takao

    2004-05-01

    The heterodyne detection technique, on which the coherent detection imaging (CDI) method founds, can discriminate and select very weak, highly directional forward scattered, and coherence retaining photons that emerge from scattering media in spite of their complex and highly scattering nature. That property enables us to reconstruct tomographic images using the same reconstruction technique as that of X-Ray CT, i.e., the filtered backprojection method. Our group had so far developed a transillumination laser CT imaging method based on the CDI method in the visible and near-infrared regions and reconstruction from projections, and reported a variety of tomographic images both in vitro and in vivo of biological objects to demonstrate the effectiveness to biomedical use. Since the previous system was not optimized, it took several hours to obtain a single image. For a practical use, we developed a prototype CDI-based imaging system using parallel fiber array and optical switches to reduce the measurement time significantly. Here, we describe a prototype transillumination laser CT imaging system using fiber-optic based on optical heterodyne detection for early diagnosis of rheumatoid arthritis (RA), by demonstrating the tomographic imaging of acrylic phantom as well as the fundamental imaging properties. We expect that further refinements of the fiber-optic-based laser CT imaging system could lead to a novel and practical diagnostic tool for rheumatoid arthritis and other joint- and bone-related diseases in human finger.

  5. Ultrasound Guidance for Botulinum Neurotoxin Chemodenervation Procedures

    Directory of Open Access Journals (Sweden)

    Katharine E. Alter

    2017-12-01

    Full Text Available Injections of botulinum neurotoxins (BoNTs are prescribed by clinicians for a variety of disorders that cause over-activity of muscles; glands; pain and other structures. Accurately targeting the structure for injection is one of the principle goals when performing BoNTs procedures. Traditionally; injections have been guided by anatomic landmarks; palpation; range of motion; electromyography or electrical stimulation. Ultrasound (US based imaging based guidance overcomes some of the limitations of traditional techniques. US and/or US combined with traditional guidance techniques is utilized and or recommended by many expert clinicians; authors and in practice guidelines by professional academies. This article reviews the advantages and disadvantages of available guidance techniques including US as well as technical aspects of US guidance and a focused literature review related to US guidance for chemodenervation procedures including BoNTs injection.

  6. Gamma Ray Tomographic Scan Method for Large Scale Industrial Plants

    International Nuclear Information System (INIS)

    Moon, Jin Ho; Jung, Sung Hee; Kim, Jong Bum; Park, Jang Geun

    2011-01-01

    The gamma ray tomography systems have been used to investigate a chemical process for last decade. There have been many cases of gamma ray tomography for laboratory scale work but not many cases for industrial scale work. Non-tomographic equipment with gamma-ray sources is often used in process diagnosis. Gamma radiography, gamma column scanning and the radioisotope tracer technique are examples of gamma ray application in industries. In spite of many outdoor non-gamma ray tomographic equipment, the most of gamma ray tomographic systems still remained as indoor equipment. But, as the gamma tomography has developed, the demand on gamma tomography for real scale plants also increased. To develop the industrial scale system, we introduced the gamma-ray tomographic system with fixed detectors and rotating source. The general system configuration is similar to 4 th generation geometry. But the main effort has been made to actualize the instant installation of the system for real scale industrial plant. This work would be a first attempt to apply the 4th generation industrial gamma tomographic scanning by experimental method. The individual 0.5-inch NaI detector was used for gamma ray detection by configuring circular shape around industrial plant. This tomographic scan method can reduce mechanical complexity and require a much smaller space than a conventional CT. Those properties make it easy to get measurement data for a real scale plant

  7. An attenuation measurement technique for rotating planar detector positron tomographs

    International Nuclear Information System (INIS)

    McNeil, P.A.; Julyan, P.J.; Parker, D.J.

    1997-01-01

    This paper presents a new attenuation measurement technique suitable for rotating planar detector positron tomographs. Transmission measurements are made using two unshielded positron-emitting line sources, one attached to the front face of each detector. Many of the scattered and accidental coincidences are rejected by including only those coincidences that form a vector passing within a predetermined distance of either line source. Some scattered and accidental coincidences are still included, which reduces the measured linear attenuation; in principle their contribution can be accurately estimated and subtracted, but in practice, when limited statistics are available (as is the case with the multi-wire Birmingham positron camera), this background subtraction unacceptably increases the noise. Instead an attenuation image having the correct features can be reconstructed from the measured projections. For objects containing only a few discrete linear attenuation coefficients, segmentation of this attenuation image reduces noise and allows the correct linear attenuation coefficients to be restored by renormalization. Reprojection through the segmented image may then provide quantitatively correct attenuation correction factors of sufficient statistical quality to correct for attenuation in PET emission images. (author)

  8. Tomographically-imaged subducted slabs and magmatic history of Caribbean and Pacific subduction beneath Colombia

    Science.gov (United States)

    Bernal-Olaya, R.; Mann, P.; Vargas, C. A.; Koulakov, I.

    2013-12-01

    We define the length and geometry of eastward and southeastward-subducting slabs beneath northwestern South America in Colombia using ~100,000 earthquake events recorded by the Colombian National Seismic Network from 1993 to 2012. Methods include: hypocenter relocation, compilation of focal mechanisms, and P and S wave tomographic calculations performed using LOTOS and Seisan. The margins of Colombia include four distinct subduction zones based on slab dip: 1) in northern Colombia, 12-16-km-thick oceanic crust subducts at a modern GPS rate of 20 mm/yr in a direction of 110 degrees at a shallow angle of 8 degrees; as a result of its low dip, Pliocene-Pleistocene volcanic rocks are present 400 km from the frontal thrust; magmatic arc migration to the east records 800 km of subduction since 58 Ma ago (Paleocene) with shallow subduction of the Caribbean oceanic plateau starting ~24-33 Ma (Miocene); at depths of 90-150 km, the slab exhibits a negative velocity anomaly we associate with pervasive fracturing; 2) in the central Colombia-Panama area, we define an area of 30-km-thick crust of the Panama arc colliding/subducting at a modern 30/mm in a direction of 95 degrees; the length of this slab shows subduction/collision initiated after 20 Ma (Middle Miocene); we call this feature the Panama indenter since it has produced a V-shaped indentation of the Colombian margin and responsible for widespread crustal deformation and topographic uplift in Colombia; an incipient subduction area is forming near the Panama border with intermediate earthquakes at an eastward dip of 70 degrees to depths of ~150 km; this zone is not visible on tomographic images; 3) a 250-km-wide zone of Miocene oceanic crust of the Nazca plate flanking the Panama indenter subducts at a rate of 25 mm/yr in a direction of 55 degrees and at a normal dip of 40 degrees; the length of this slab suggests subduction began at ~5 Ma; 4) the Caldas tear defines a major dip change to the south where a 35 degrees

  9. Volume of interest CBCT and tube current modulation for image guidance using dynamic kV collimation

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, David, E-mail: david.parsons@dal.ca, E-mail: james.robar@nshealth.ca [Department of Physics and Atmospheric Science, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7 (Canada); Robar, James L., E-mail: david.parsons@dal.ca, E-mail: james.robar@nshealth.ca [Department of Radiation Oncology and Department of Physics and Atmospheric Science, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7 (Canada)

    2016-04-15

    Purpose: The focus of this work is the development of a novel blade collimation system enabling volume of interest (VOI) CBCT with tube current modulation using the kV image guidance source on a linear accelerator. Advantages of the system are assessed, particularly with regard to reduction and localization of dose and improvement of image quality. Methods: A four blade dynamic kV collimator was developed to track a VOI during a CBCT acquisition. The current prototype is capable of tracking an arbitrary volume defined by the treatment planner for subsequent CBCT guidance. During gantry rotation, the collimator tracks the VOI with adjustment of position and dimension. CBCT image quality was investigated as a function of collimator dimension, while maintaining the same dose to the VOI, for a 22.2 cm diameter cylindrical water phantom with a 9 mm diameter bone insert centered on isocenter. Dose distributions were modeled using a dynamic BEAMnrc library and DOSXYZnrc. The resulting VOI dose distributions were compared to full-field CBCT distributions to quantify dose reduction and localization to the target volume. A novel method of optimizing x-ray tube current during CBCT acquisition was developed and assessed with regard to contrast-to-noise ratio (CNR) and imaging dose. Results: Measurements show that the VOI CBCT method using the dynamic blade system yields an increase in contrast-to-noise ratio by a factor of approximately 2.2. Depending upon the anatomical site, dose was reduced to 15%–80% of the full-field CBCT value along the central axis plane and down to less than 1% out of plane. The use of tube current modulation allowed for specification of a desired SNR within projection data. For approximately the same dose to the VOI, CNR was further increased by a factor of 1.2 for modulated VOI CBCT, giving a combined improvement of 2.6 compared to full-field CBCT. Conclusions: The present dynamic blade system provides significant improvements in CNR for the same

  10. Advanced approach for intraoperative MRI guidance and potential benefit for neurosurgical applications.

    Science.gov (United States)

    Busse, Harald; Schmitgen, Arno; Trantakis, Christos; Schober, Ralf; Kahn, Thomas; Moche, Michael

    2006-07-01

    To present an advanced approach for intraoperative image guidance in an open 0.5 T MRI and to evaluate its effectiveness for neurosurgical interventions by comparison with a dynamic scan-guided localization technique. The built-in scan guidance mode relied on successive interactive MRI scans. The additional advanced mode provided real-time navigation based on reformatted high-quality, intraoperatively acquired MR reference data, allowed multimodal image fusion, and used the successive scans of the built-in mode for quick verification of the position only. Analysis involved tumor resections and biopsies in either scan guidance (N = 36) or advanced mode (N = 59) by the same three neurosurgeons. Technical, surgical, and workflow aspects were compared. The image quality and hand-eye coordination of the advanced approach were improved. While the average extent of resection, neurologic outcome after functional MRI (fMRI) integration, and diagnostic yield appeared to be slightly better under advanced guidance, particularly for the main surgeon, statistical analysis revealed no significant differences. Resection times were comparable, while biopsies took around 30 minutes longer. The presented approach is safe and provides more detailed images and higher navigation speed at the expense of actuality. The surgical outcome achieved with advanced guidance is (at least) as good as that obtained with dynamic scan guidance. (c) 2006 Wiley-Liss, Inc.

  11. Laparoscopic Heller Myotomy for Non-Dilated Esophageal Achalasia in Children with Intraoperative Stepped Dilation Under Image Guidance: Attempting Complete Myotomy.

    Science.gov (United States)

    Miyano, Go; Miyake, Hiromu; Koyama, Mariko; Morita, Keiichi; Kaneshiro, Masakatsu; Nouso, Hiroshi; Yamoto, Masaya; Fukumoto, Koji; Urushihara, Naoto

    2016-05-01

    This study presents a modified surgical approach to laparoscopic myotomy for achalasia using stepped dilation with a Rigiflex balloon and contrast medium under image guidance. A 10-year-old boy with persistent dysphagia and vomiting had ingested only liquids for 3 months, losing >10 kg in body weight. Barium swallow and esophageal manometry diagnosed esophageal achalasia with mild esophageal dilatation. After failed pneumatic dilatation, laparoscopic Heller myotomy with Dor fundoplication was performed. Prior to surgery, a Rigiflex balloon dilator was placed within the esophagus near the diaphragmatic hiatus. A four-port technique was used, and mobilization of the esophagus was limited to the anterior aspect. A 5-cm Heller myotomy was performed, extending another 2 cm onto the anterior gastric wall. During myotomy, the Rigiflex balloon was serially dilated from 30 to 50 mL, and filled with contrast medium under fluoroscopic image guidance in order to maintain appropriate tension on the esophagus to facilitate myotomy, and to confirm adequate myotomy with sufficient release of lower esophageal sphincter by resecting residual circular muscle fibers. Residual circular muscle fibers can be simultaneously visualized under both fluoroscopic image guidance and direct observation through the laparoscope, and they were cut precisely until the residual notch fully disappeared. Dor fundoplication was completed. The operative time was 180 minutes, and oral intake was started after esophagography on postoperative day 1. As of the 12-month follow-up, the patient has not shown any symptoms, and his postoperative course appeared satisfactory.

  12. Tomographic Approach in Three-Orthogonal-Basis Quantum Key Distribution

    International Nuclear Information System (INIS)

    Liang Wen-Ye; Yin Zhen-Qiang; Chen Hua; Li Hong-Wei; Chen Wei; Han Zheng-Fu; Wen Hao

    2015-01-01

    At present, there is an increasing awareness of some three-orthogonal-basis quantum key distribution protocols, such as, the reference-frame-independent (RFI) protocol and the six-state protocol. For secure key rate estimations of these protocols, there are two methods: one is the conventional approach, and another is the tomographic approach. However, a comparison between these two methods has not been given yet. In this work, with the general model of rotation channel, we estimate the key rate using conventional and tomographic methods respectively. Results show that conventional estimation approach in RFI protocol is equivalent to tomographic approach only in the case of that one of three orthogonal bases is always aligned. In other cases, tomographic approach performs much better than the respective conventional approaches of the RFI protocol and the six-state protocol. Furthermore, based on the experimental data, we illustrate the deep connections between tomography and conventional RFI approach representations. (paper)

  13. Radiographic test phantom for computed tomographic lung nodule analysis

    International Nuclear Information System (INIS)

    Zerhouni, E.A.

    1987-01-01

    This patent describes a method for evaluating a computed tomograph scan of a nodule in a lung of a human or non-human animal. The method comprises generating a computer tomograph of a transverse section of the animal containing lung and nodule tissue, and generating a second computer tomograph of a test phantom comprising a device which simulates the transverse section of the animal. The tissue simulating portions of the device are constructed of materials having radiographic densities substantially identical to those of the corresponding tissue in the simulated transverse section of the animal and have voids therein which simulate, in size and shape, the lung cavities in the transverse section and which contain a test reference nodule constructed of a material of predetermined radiographic density which simulates in size, shape and position within a lung cavity void of the test phantom the nodule in the transverse section of the animal and comparing the respective tomographs

  14. Development of the Shimadzu computed tomographic scanner SCT-200N

    International Nuclear Information System (INIS)

    Ishihara, Hiroshi; Yamaoka, Nobuyuki; Saito, Masahiro

    1982-01-01

    The Shimadzu Computed Tomographic Scanner SCT-200N has been developed as an ideal CT scanner for diagnosing the head and spine. Due to the large aperture, moderate scan time and the Zoom Scan Mode, any part of the body can be scanned. High quality image can be obtained by adopting the precisely stabilized X-ray unit and densely packed array of 64-detectors. As for its operation, capability of computed radiography (CR) prior to patient positioning and real time reconstruction ensure efficient patient through-put. Details of the SCT-200N are described in this paper. (author)

  15. The effects of temporomandibular joint internal derangement and degenerative joint disease on tomographic and arthrotomographic images.

    Science.gov (United States)

    Brand, J W; Whinery, J G; Anderson, Q N; Keenan, K M

    1989-02-01

    In a blind study, 243 arthrograms were interpreted as showing normal disk position, anterior disk displacement with reduction, or anterior disk displacement without reduction. The presence or absence of a perforation of the posterior attachment or disk was recorded. Later, tomograms of the same patient were interpreted. The presence or absence of evidence of temporomandibular degenerative joint disease (TMDJD) was recorded. The condyle-to-fossa relationship was characterized as retropositioned or not retropositioned. O the 106 cases with tomographic evidence of TMDJD, 100 (94%) had arthrographic evidence of internal derangement (p less than 0.0001), whereas 47% of the cases with internal derangement (211) had evidence of TMDJD. Perforations were seen in 29 (27%) of the cases with degenerative joint disease and in none (0%) of the cases without TMDJD (p less than 0.001). In cases without TMDJD, 90% of the cases with internal derangement revealed condylar retropositioning (p less than 0.0001). With tomographic evidence of TMDJD present, the relationship between condylar position and disk position was not significant.

  16. Impact of Image Guidance on Outcomes After External Beam Radiotherapy for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Willoughby, Twyla R.; Reddy, Chandana A.; Klein, Eric A.; Mahadevan, Arul

    2008-01-01

    Purpose: To verify whether rectal distention at the time of planning impacts outcomes in patients with localized prostate cancer treated with daily image guidance. Methods and Materials: Between 1998 and 2002, a total of 488 prostate cancer patients were treated with intensity-modulated radiotherapy. The radiation dose was 70 Gy delivered at 2.5 Gy per fraction in all cases. All cases were treated with a 4-mm margin posteriorly. In all cases the total rectal volume documented on the CT scan was used for treatment planning. No special bowel preparation instructions were given, either for the simulation or the daily treatments. Before each daily treatment, alignment of the prostate was performed with the B-mode acquisition and targeting (BAT) transabdominal ultrasound system. The median follow-up for all 488 patients was 60 months (range, 24-96 months). Results: For all patients the biochemical relapse-free survival (bRFS) rate at 5 years was 86%. The 5-year bRFS rate for the rectal distention 3 , 50 to 3 , and ≥100 cm 3 groups was 90%, 83%, and 85%, respectively (p = 0.18). To adjust for other potential variables affecting bRFS rates, a multivariate time-to-failure analysis using the Cox proportional hazards model was performed. Rectal distention was not an independent predictor of biochemical failure on multivariate analysis (p = 0.80). Rectal distention was not a predictor of rectal or urinary toxicity. Conclusion: The use of daily image guidance eliminates errors such as rectal distention at the initial planning stage that can affect outcomes after radiotherapy for localized prostate cancer

  17. Tomographic image reconstruction using Artificial Neural Networks

    International Nuclear Information System (INIS)

    Paschalis, P.; Giokaris, N.D.; Karabarbounis, A.; Loudos, G.K.; Maintas, D.; Papanicolas, C.N.; Spanoudaki, V.; Tsoumpas, Ch.; Stiliaris, E.

    2004-01-01

    A new image reconstruction technique based on the usage of an Artificial Neural Network (ANN) is presented. The most crucial factor in designing such a reconstruction system is the network architecture and the number of the input projections needed to reconstruct the image. Although the training phase requires a large amount of input samples and a considerable CPU time, the trained network is characterized by simplicity and quick response. The performance of this ANN is tested using several image patterns. It is intended to be used together with a phantom rotating table and the γ-camera of IASA for SPECT image reconstruction

  18. First experience with a mobile computed tomograph in the USSR

    International Nuclear Information System (INIS)

    Portnoj, L.M.

    1989-01-01

    Utilization experience of mobile computerized tomograph mounted in the bus is presented. Problems concerning staff, selection of medical base institutes etc are considered. Efficiency of mobile computerized tomographes in revealing different diseases is pointed out

  19. Autonomous aerial vehicles : guidance, control, signal and image processing platform

    International Nuclear Information System (INIS)

    Al-Jarrah, M.; Adiansyah, S.; Marji, Z. M.; Chowdhury, M. S.

    2011-01-01

    used as fusion algorithm for position and poses estimation. Then path planning, trajectory generation and trajectory guidance alternative strategies is presented. One of the important UAV mission is target surveillance using an onboard vision system. AUS-UAV Mazari is using a gimbaled camera for target monitoring and target tracking using basic digital image processing and techniques. Successful moving target geo-location algorithms were developed and results will be presented. Future plan is to develop a cooperation strategy between several vehicles in the air and on the ground. Use of vision system to aid the vehicle in localization using ground features is also under consideration.

  20. Rapidly-steered single-element ultrasound for real-time volumetric imaging and guidance

    Science.gov (United States)

    Stauber, Mark; Western, Craig; Solek, Roman; Salisbury, Kenneth; Hristov, Dmitre; Schlosser, Jeffrey

    2016-03-01

    Volumetric ultrasound (US) imaging has the potential to provide real-time anatomical imaging with high soft-tissue contrast in a variety of diagnostic and therapeutic guidance applications. However, existing volumetric US machines utilize "wobbling" linear phased array or matrix phased array transducers which are costly to manufacture and necessitate bulky external processing units. To drastically reduce cost, improve portability, and reduce footprint, we propose a rapidly-steered single-element volumetric US imaging system. In this paper we explore the feasibility of this system with a proof-of-concept single-element volumetric US imaging device. The device uses a multi-directional raster-scan technique to generate a series of two-dimensional (2D) slices that were reconstructed into three-dimensional (3D) volumes. At 15 cm depth, 90° lateral field of view (FOV), and 20° elevation FOV, the device produced 20-slice volumes at a rate of 0.8 Hz. Imaging performance was evaluated using an US phantom. Spatial resolution was 2.0 mm, 4.7 mm, and 5.0 mm in the axial, lateral, and elevational directions at 7.5 cm. Relative motion of phantom targets were automatically tracked within US volumes with a mean error of -0.3+/-0.3 mm, -0.3+/-0.3 mm, and -0.1+/-0.5 mm in the axial, lateral, and elevational directions, respectively. The device exhibited a mean spatial distortion error of 0.3+/-0.9 mm, 0.4+/-0.7 mm, and -0.3+/-1.9 in the axial, lateral, and elevational directions. With a production cost near $1000, the performance characteristics of the proposed system make it an ideal candidate for diagnostic and image-guided therapy applications where form factor and low cost are paramount.

  1. Evaluation of quality of tomographs of Rio de Janeiro state, Brazil; Avaliacao da qualidade dos tomografos do estado do Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Travassos, P.C.B.; Belem, V.R.; Magalhaes, L.A.; Almeida, C.E.A. de, E-mail: luisalexandregm@hotmail.com [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Ciencias Radiologicas

    2014-07-01

    Computerized tomographs used in 56 institutions in the state of Rio de Janeiro were evaluated. Criteria of image quality and dosimetry were submitted. The results showed that some not performed optimize their protocols examinations or perform wrongly, which results in an increase in the dose received by patients, and an image in compromised quality. (author)

  2. Computed tomographic findings of intracranial pyogenic abscess

    International Nuclear Information System (INIS)

    Kim, S. J.; Suh, J. H.; Park, C. Y.; Lee, K. C.; Chung, S. S.

    1982-01-01

    The early diagnosis and effective treatment of brain abscess pose a difficult clinical problem. With the advent of computed tomography, however, it appears that mortality due to intracranial abscess has significantly diminished. 54 cases of intracranial pyogenic abscess are presented. Etiologic factors and computed tomographic findings are analyzed and following result are obtained. 1. The common etiologic factors are otitis media, post operation, and head trauma, in order of frequency. 2. The most common initial computed tomographic findings of brain abscess is ring contrast enhancement with surrounding brain edema. 3. The most characteristic computed tomographic finding of ring contrast enhancement is smooth thin walled ring contrast enhancement. 4. Most of thick irregular ring contrast enhancement are abscess associated with cyanotic heart disease or poor operation. 5. The most common findings of epidural and subdural empyema is crescentic radiolucent area with thin wall contrast enhancement without surrounding brain edema in convexity of brain

  3. Design and implementation of a PC-based image-guided surgical system.

    Science.gov (United States)

    Stefansic, James D; Bass, W Andrew; Hartmann, Steven L; Beasley, Ryan A; Sinha, Tuhin K; Cash, David M; Herline, Alan J; Galloway, Robert L

    2002-11-01

    In interactive, image-guided surgery, current physical space position in the operating room is displayed on various sets of medical images used for surgical navigation. We have developed a PC-based surgical guidance system (ORION) which synchronously displays surgical position on up to four image sets and updates them in real time. There are three essential components which must be developed for this system: (1) accurately tracked instruments; (2) accurate registration techniques to map physical space to image space; and (3) methods to display and update the image sets on a computer monitor. For each of these components, we have developed a set of dynamic link libraries in MS Visual C++ 6.0 supporting various hardware tools and software techniques. Surgical instruments are tracked in physical space using an active optical tracking system. Several of the different registration algorithms were developed with a library of robust math kernel functions, and the accuracy of all registration techniques was thoroughly investigated. Our display was developed using the Win32 API for windows management and tomographic visualization, a frame grabber for live video capture, and OpenGL for visualization of surface renderings. We have begun to use this current implementation of our system for several surgical procedures, including open and minimally invasive liver surgery.

  4. Nigerian Journal of Guidance and Counselling

    African Journals Online (AJOL)

    The Nigerian Journal of Guidance and Counselling. ... Journal Homepage Image ... by the Department of Counsellor Education, University of Ilorin, Ilorin, Nigeria. ... Awareness and use of Meseron therapy among clinical psychologists in ...

  5. Use of a Diagnostic Score to Prioritize Computed Tomographic (CT Imaging for Patients Suspected of Ischemic Stroke Who May Benefit from Thrombolytic Therapy.

    Directory of Open Access Journals (Sweden)

    Wen Yea Hwong

    Full Text Available A shortage of computed tomographic (CT machines in low and middle income countries often results in delayed CT imaging for patients suspected of a stroke. Yet, time constraint is one of the most important aspects for patients with an ischemic stroke to benefit from thrombolytic therapy. We set out to assess whether application of the Siriraj Stroke Score is able to assist physicians in prioritizing patients with a high probability of having an ischemic stroke for urgent CT imaging.From the Malaysian National Neurology Registry, we selected patients aged 18 years and over with clinical features suggesting of a stroke, who arrived in the hospital 4.5 hours or less from ictus. The prioritization of receiving CT imaging was left to the discretion of the treating physician. We applied the Siriraj Stroke Score to all patients, refitted the score and defined a cut-off value to best distinguish an ischemic stroke from a hemorrhagic stroke.Of the 2176 patients included, 73% had an ischemic stroke. Only 33% of the ischemic stroke patients had CT imaging within 4.5 hours. The median door-to-scan time for these patients was 4 hours (IQR: 1;16. With the recalibrated score, it would have been possible to prioritize 95% (95% CI: 94%-96% of patients with an ischemic stroke for urgent CT imaging.In settings where CT imaging capacity is limited, we propose the use of the Siriraj Stroke Score to prioritize patients with a probable ischemic stroke for urgent CT imaging.

  6. Optical tomographic imaging for breast cancer detection

    Science.gov (United States)

    Cong, Wenxiang; Intes, Xavier; Wang, Ge

    2017-09-01

    Diffuse optical breast imaging utilizes near-infrared (NIR) light propagation through tissues to assess the optical properties of tissues for the identification of abnormal tissue. This optical imaging approach is sensitive, cost-effective, and does not involve any ionizing radiation. However, the image reconstruction of diffuse optical tomography (DOT) is a nonlinear inverse problem and suffers from severe illposedness due to data noise, NIR light scattering, and measurement incompleteness. An image reconstruction method is proposed for the detection of breast cancer. This method splits the image reconstruction problem into the localization of abnormal tissues and quantification of absorption variations. The localization of abnormal tissues is performed based on a well-posed optimization model, which can be solved via a differential evolution optimization method to achieve a stable reconstruction. The quantification of abnormal absorption is then determined in localized regions of relatively small extents, in which a potential tumor might be. Consequently, the number of unknown absorption variables can be greatly reduced to overcome the underdetermined nature of DOT. Numerical simulation experiments are performed to verify merits of the proposed method, and the results show that the image reconstruction method is stable and accurate for the identification of abnormal tissues, and robust against the measurement noise of data.

  7. Development of a X-ray micro-tomograph and its application to reservoir rocks characterization

    International Nuclear Information System (INIS)

    Ferreira de Paiva, R.

    1995-10-01

    We describe the construction and application to studies in three dimensions of a laboratory micro-tomograph for the characterisation of heterogeneous solids at the scale of a few microns. The system is based on an electron microprobe and a two dimensional X-ray detector. The use of a low beam divergence for image acquisition allows use of simple and rapid reconstruction software whilst retaining reasonable acquisition times. Spatial resolutions of better than 3 microns in radiography and 10 microns in tomography are obtained. The applications of microtomography in the petroleum industry are illustrated by the study of fibre orientation in polymer composites, of the distribution of minerals and pore space in reservoir rocks, and of the interaction of salt water with a model porous medium. A correction for X-ray beam hardening is described and used to obtain improved discrimination of the phases present in the sample. In the case of a North Sea reservoir rock we show the possibility to distinguish quartz, feldspar and in certain zone kaolinite. The representativeness of the tomographic reconstruction is demonstrated by comparing the surface of the reconstructed specimen with corresponding images obtained in scanning electron microscopy. (author). 58 refs., 10 tabs., 71 photos

  8. Physics-based shape matching for intraoperative image guidance

    Energy Technology Data Exchange (ETDEWEB)

    Suwelack, Stefan, E-mail: suwelack@kit.edu; Röhl, Sebastian; Bodenstedt, Sebastian; Reichard, Daniel; Dillmann, Rüdiger; Speidel, Stefanie [Institute for Anthropomatics and Robotics, Karlsruhe Institute of Technology, Adenauerring 2, Karlsruhe 76131 (Germany); Santos, Thiago dos; Maier-Hein, Lena [Computer-assisted Interventions, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Wagner, Martin; Wünscher, Josephine; Kenngott, Hannes; Müller, Beat P. [General, Visceral and Transplantation Surgery, Heidelberg University Hospital, Im Neuenheimer Feld 110, Heidelberg 69120 (Germany)

    2014-11-01

    Purpose: Soft-tissue deformations can severely degrade the validity of preoperative planning data during computer assisted interventions. Intraoperative imaging such as stereo endoscopic, time-of-flight or, laser range scanner data can be used to compensate these movements. In this context, the intraoperative surface has to be matched to the preoperative model. The shape matching is especially challenging in the intraoperative setting due to noisy sensor data, only partially visible surfaces, ambiguous shape descriptors, and real-time requirements. Methods: A novel physics-based shape matching (PBSM) approach to register intraoperatively acquired surface meshes to preoperative planning data is proposed. The key idea of the method is to describe the nonrigid registration process as an electrostatic–elastic problem, where an elastic body (preoperative model) that is electrically charged slides into an oppositely charged rigid shape (intraoperative surface). It is shown that the corresponding energy functional can be efficiently solved using the finite element (FE) method. It is also demonstrated how PBSM can be combined with rigid registration schemes for robust nonrigid registration of arbitrarily aligned surfaces. Furthermore, it is shown how the approach can be combined with landmark based methods and outline its application to image guidance in laparoscopic interventions. Results: A profound analysis of the PBSM scheme based on in silico and phantom data is presented. Simulation studies on several liver models show that the approach is robust to the initial rigid registration and to parameter variations. The studies also reveal that the method achieves submillimeter registration accuracy (mean error between 0.32 and 0.46 mm). An unoptimized, single core implementation of the approach achieves near real-time performance (2 TPS, 7–19 s total registration time). It outperforms established methods in terms of speed and accuracy. Furthermore, it is shown that the

  9. Craniofacial fibrous dysplasia: Report of a case using computed tomographic scan diagnosis

    Directory of Open Access Journals (Sweden)

    Nikhil Diwan

    2013-01-01

    Full Text Available Fibro-osseous lesions are benign mesenchymal tumors in which mineralized tissue, blood vessels, and giant cells, in varying proportions, replace normal bone. Although this group of lesions includes reactive lesions, harmatomas, and neoplasms, they cannot be distinguished only on the basis of the histopathology which can only confirm their common fibro-osseous nature. Definitive diagnosis requires thorough radiological evaluation. Computed tomographic images of craniofacial fibrous dysplasia on bone windows may be helpful and allow precise pre-operative diagnosis and surgical planning.

  10. Radionuclide imaging with coded apertures and three-dimensional image reconstruction from focal-plane tomography

    International Nuclear Information System (INIS)

    Chang, L.T.

    1976-05-01

    Two techniques for radionuclide imaging and reconstruction have been studied;; both are used for improvement of depth resolution. The first technique is called coded aperture imaging, which is a technique of tomographic imaging. The second technique is a special 3-D image reconstruction method which is introduced as an improvement to the so called focal-plane tomography

  11. Cone beam computed tomography and its image guidance technology during percutaneous nucleoplasty procedures at L5/S1 lumbar level

    Energy Technology Data Exchange (ETDEWEB)

    Ierardi, Anna Maria; Piacentino, Filippo; Giorlando, Francesca [University of Insubria, Unit of Interventional Radiology, Department of Radiology, Varese (Italy); Magenta Biasina, Alberto; Carrafiello, Gianpaolo [University of Milan, San Paolo Hospital, Department of Diagnostic and Interventional Radiology, Milan (Italy); Bacuzzi, Alessandro [University of Insubria, Anaesthesia and Palliative Care, Varese (Italy); Novario, Raffaele [University of Insubria, Medical Physics Department, Varese (Italy)

    2016-12-15

    To demonstrate the feasibility of percutaneous nucleoplasty procedures at L5/S1 level using cone beam CT (CBCT) and its associated image guidance technology for the treatment of lumbar disc herniation (LDH). We retrospectively reviewed 25 cases (20 men, 5 women) of LDH at L5/S1 levels. CBCT as guidance imaging was chosen after a first unsuccessful fluoroscopy attempt that was related to complex anatomy (n = 15), rapid pathological changes due to degenerative diseases (n = 7) or both (n = 3). Technical success, defined as correct needle positioning in the target LDH, and safety were evaluated; overall procedure time and radiation dose were registered. A visual analog scale (VAS) was used to evaluate pain and discomfort pre-intervention after 1 week and 1, 3, and 6 months after the procedure. Technical success was 100 %; using CBCT as guidance imaging the needle was correctly positioned at the first attempt in 20 out of 25 patients. Neither major nor minor complications were registered during or after the procedure. The average procedure time was 11 min and 56 s (range, 9-15 min), whereas mean procedural radiation dose was 46.25 Gy.cm{sup 2} (range 38.10-52.84 Gy.cm{sup 2}), and mean fluoroscopy time was 5 min 34 s (range 3 min 40 s to 6 min 55 s). The VAS pain score decreased significantly from 7.6 preoperatively to 3.9 at 1 week, 2.8 at 1 month, 2.1 at 3 months, and 1.6 at 6 months postoperatively. CBCT-guided percutaneous nucleoplasty is a highly effective technique for LDH with acceptable procedure time and radiation dose. (orig.)

  12. An original acquisition chain for the TOHR High Resolution Tomograph

    International Nuclear Information System (INIS)

    Pinot, Laurent

    1999-01-01

    The framework of this work is part of a new approach of emission tomography adapted to small animals. The principle of our tomographic system TOHR (French acronym for High Resolution Tomograph) is based on the use of large solid angle and high resolution focusing collimators each mounted in front of a detection module of high efficiency. With a first-generation acquisition chain we were able to characterize TOHR, however, to take fully advantage of the TOHR possibilities, a completely new acquisition scheme had to be designed. This system, being the main topic of this work, makes use of temporal information. The detection of a particle that entered the detector is translated into temporal logical signals. These signals pass into a time coding circuitry and the coded results are transferred in a digital processor. According to the initial terms of delivery, the developed acquisition chain steers the detection of events dependent on the deposited energy and time of arrival. The latter is done by coincidence measurements. All elements are mounted on a special board included into a PC unit and a dedicated program controls the whole system. First experiments showed up the interest of the new acquisition unit for other application in physics or medical imaging

  13. Tomographs based on non-conventional radiation sources and methods

    International Nuclear Information System (INIS)

    Barbuzza, R.; Fresno, M. del; Venere, Marcelo J.; Clausse, Alejandro; Moreno, C.

    2000-01-01

    Computer techniques for tomographic reconstruction of objects X-rayed with a compact plasma focus (PF) are presented. The implemented reconstruction algorithms are based on stochastic searching of solutions of Radon equation, using Genetic Algorithms and Monte Carlo methods. Numerical experiments using actual projections were performed concluding the feasibility of the application of both methods in tomographic reconstruction problem. (author)

  14. A review of US anthropometric reference data (1971-2000) with comparisons to both stylized and tomographic anatomic models

    International Nuclear Information System (INIS)

    Huh, C; Bolch, W E

    2003-01-01

    Two classes of anatomic models currently exist for use in both radiation protection and radiation dose reconstruction: stylized mathematical models and tomographic voxel models. The former utilize 3D surface equations to represent internal organ structure and external body shape, while the latter are based on segmented CT or MR images of a single individual. While tomographic models are clearly more anthropomorphic than stylized models, a given model's characterization as being anthropometric is dependent upon the reference human to which the model is compared. In the present study, data on total body mass, standing/sitting heights and body mass index are collected and reviewed for the US population covering the time interval from 1971 to 2000. These same anthropometric parameters are then assembled for the ORNL series of stylized models, the GSF series of tomographic models (Golem, Helga, Donna, etc), the adult male Zubal tomographic model and the UF newborn tomographic model. The stylized ORNL models of the adult male and female are found to be fairly representative of present-day average US males and females, respectively, in terms of both standing and sitting heights for ages between 20 and 60-80 years. While the ORNL adult male model provides a reasonably close match to the total body mass of the average US 21-year-old male (within ∼5%), present-day 40-year-old males have an average total body mass that is ∼16% higher. For radiation protection purposes, the use of the larger 73.7 kg adult ORNL stylized hermaphrodite model provides a much closer representation of average present-day US females at ages ranging from 20 to 70 years. In terms of the adult tomographic models from the GSF series, only Donna (40-year-old F) closely matches her age-matched US counterpart in terms of average body mass. Regarding standing heights, the better matches to US age-correlated averages belong to Irene (32-year-old F) for the females and Golem (38-year-old M) for the males

  15. Enhanced imaging of microcalcifications in digital breast tomosynthesis through improved image-reconstruction algorithms

    International Nuclear Information System (INIS)

    Sidky, Emil Y.; Pan Xiaochuan; Reiser, Ingrid S.; Nishikawa, Robert M.; Moore, Richard H.; Kopans, Daniel B.

    2009-01-01

    Purpose: The authors develop a practical, iterative algorithm for image-reconstruction in undersampled tomographic systems, such as digital breast tomosynthesis (DBT). Methods: The algorithm controls image regularity by minimizing the image total p variation (TpV), a function that reduces to the total variation when p=1.0 or the image roughness when p=2.0. Constraints on the image, such as image positivity and estimated projection-data tolerance, are enforced by projection onto convex sets. The fact that the tomographic system is undersampled translates to the mathematical property that many widely varied resultant volumes may correspond to a given data tolerance. Thus the application of image regularity serves two purposes: (1) Reduction in the number of resultant volumes out of those allowed by fixing the data tolerance, finding the minimum image TpV for fixed data tolerance, and (2) traditional regularization, sacrificing data fidelity for higher image regularity. The present algorithm allows for this dual role of image regularity in undersampled tomography. Results: The proposed image-reconstruction algorithm is applied to three clinical DBT data sets. The DBT cases include one with microcalcifications and two with masses. Conclusions: Results indicate that there may be a substantial advantage in using the present image-reconstruction algorithm for microcalcification imaging.

  16. Radiographic and tomographic study of the elbow joint in dogs

    International Nuclear Information System (INIS)

    Sendyk-Grunkraut, Alessandra; Martin, Claudia M.; Souza, Alexandre N.A.; Patricio, Geni Cristina F.; Lorigados, Carla A.B.; Matera, Julia M.; Fonseca-Pinto, Ana C.B.C.

    2017-01-01

    Elbow dysplasia disease includes an united anconeal process, fragmented medial coronoid process, osteochondrosis of humeral trochlea, articular incongruity and degenerative joint disease. The aim of this study was to present detailed morphologic and morphometric aspects of the elbow joint in dog in clinical and correlate with radiographic and tomographic (CT) exam. Inter-observer variation for articular incongruity measurements by CT, comparative analysis in the radiographic exam, angle in ulnar notch and its comparative analysis between radiographic and tomographic agreement examination in 44 elbow of dogs with different ages were evaluated. The statistics analyses included the kappa coefficient and interclass correlation and Fischer's test and McNemar's test. It was evidenced that individual performance of each radiographic incidence had poor agreement with the tomographic exam, suggesting that the accomplishment of more than two radiograph views are needed. There was no agreement between the three evaluators in the ulnar notch angle at radiographic and tomographic exams. However, there was good/moderate agreement for articular incongruity measurement in the sagittal plane between evaluators. It was possible to conclude that none of the five radiographic incidences was better than the others for radiographic analysis because each incidence had a better identification of a particular elbow compartment; measurements at the tomographic exam to evaluate radioulnar incongruity had no reproductiveness in the frontal plane, but in sagittal plan had a good/moderate agreement between observers and the angle in ulnar notch presented no repeatability at radiographic exam and no reproductiveness at tomographic exam. (author)

  17. Fusion Imaging for Procedural Guidance.

    Science.gov (United States)

    Wiley, Brandon M; Eleid, Mackram F; Thaden, Jeremy J

    2018-05-01

    The field of percutaneous structural heart interventions has grown tremendously in recent years. This growth has fueled the development of new imaging protocols and technologies in parallel to help facilitate these minimally-invasive procedures. Fusion imaging is an exciting new technology that combines the strength of 2 imaging modalities and has the potential to improve procedural planning and the safety of many commonly performed transcatheter procedures. In this review we discuss the basic concepts of fusion imaging along with the relative strengths and weaknesses of static vs dynamic fusion imaging modalities. This review will focus primarily on echocardiographic-fluoroscopic fusion imaging and its application in commonly performed transcatheter structural heart procedures. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  18. Synchrotron radiation X-ray tomographic microscopy (SRXTM) of brachiopod shell interiors for taxonomy: Preliminary report

    OpenAIRE

    Motchurova-Dekova Neda; Harper David A.T.

    2010-01-01

    Synchrotron radiation X-ray tomographic microscopy (SRXTM) is a non-destructive technique for the investigation and visualization of the internal features of solid opaque objects, which allows reconstruction of a complete three-dimensional image of internal structures by recording of the differences in the effects on the passage of waves of energy reacting with those structures. Contrary to X-rays, produced in a conventional X-ray tube, the intense synchrot...

  19. 3D Tomographic SAR Imaging in Densely Vegetated Mountainous Rural Areas in China and Sweden

    Science.gov (United States)

    Feng, L.; Muller, J. P., , Prof

    2017-12-01

    3D SAR Tomography (TomoSAR) and 4D SAR Differential Tomography (Diff-TomoSAR) exploit multi-baseline SAR data stacks to create an important new innovation of SAR Interferometry, to unscramble complex scenes with multiple scatterers mapped into the same SAR cell. In addition to this 3-D shape reconstruction and deformation solution in complex urban/infrastructure areas, and recent cryospheric ice investigations, emerging tomographic remote sensing applications include forest applications, e.g. tree height and biomass estimation, sub-canopy topographic mapping, and even search, rescue and surveillance. However, these scenes are characterized by temporal decorrelation of scatterers, orbital, tropospheric and ionospheric phase distortion and an open issue regarding possible height blurring and accuracy losses for TomoSAR applications particularly in densely vegetated mountainous rural areas. Thus, it is important to develop solutions for temporal decorrelation, orbital, tropospheric and ionospheric phase distortion.We report here on 3D imaging (especially in vertical layers) over densely vegetated mountainous rural areas using 3-D SAR imaging (SAR tomography) derived from data stacks of X-band COSMO-SkyMed Spotlight and L band ALOS-1 PALSAR data stacks over Dujiangyan Dam, Sichuan, China and L and P band airborne SAR data (BioSAR 2008 - ESA) in the Krycklan river catchment, Northern Sweden. The new TanDEM-X 12m DEM is used to assist co - registration of all the data stacks over China first. Then, atmospheric correction is being assessed using weather model data such as ERA-I, MERRA, MERRA-2, WRF; linear phase-topography correction and MODIS spectrometer correction will be compared and ionospheric correction methods are discussed to remove tropospheric and ionospheric delay. Then the new TomoSAR method with the TanDEM-X 12m DEM is described to obtain the number of scatterers inside each pixel, the scattering amplitude and phase of each scatterer and finally extract

  20. Dense velocity reconstruction from tomographic PTV with material derivatives

    Science.gov (United States)

    Schneiders, Jan F. G.; Scarano, Fulvio

    2016-09-01

    A method is proposed to reconstruct the instantaneous velocity field from time-resolved volumetric particle tracking velocimetry (PTV, e.g., 3D-PTV, tomographic PTV and Shake-the-Box), employing both the instantaneous velocity and the velocity material derivative of the sparse tracer particles. The constraint to the measured temporal derivative of the PTV particle tracks improves the consistency of the reconstructed velocity field. The method is christened as pouring time into space, as it leverages temporal information to increase the spatial resolution of volumetric PTV measurements. This approach becomes relevant in cases where the spatial resolution is limited by the seeding concentration. The method solves an optimization problem to find the vorticity and velocity fields that minimize a cost function, which includes next to instantaneous velocity, also the velocity material derivative. The velocity and its material derivative are related through the vorticity transport equation, and the cost function is minimized using the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. The procedure is assessed numerically with a simulated PTV experiment in a turbulent boundary layer from a direct numerical simulation (DNS). The experimental validation considers a tomographic particle image velocimetry (PIV) experiment in a similar turbulent boundary layer and the additional case of a jet flow. The proposed technique (`vortex-in-cell plus', VIC+) is compared to tomographic PIV analysis (3D iterative cross-correlation), PTV interpolation methods (linear and adaptive Gaussian windowing) and to vortex-in-cell (VIC) interpolation without the material derivative. A visible increase in resolved details in the turbulent structures is obtained with the VIC+ approach, both in numerical simulations and experiments. This results in a more accurate determination of the turbulent stresses distribution in turbulent boundary layer investigations. Data from a jet

  1. Construction of a positron emission tomograph with 2.4 mm detectors

    International Nuclear Information System (INIS)

    McIntyre, J.A.; Sprosst, R.L.; Wang, K.

    1986-01-01

    One-quarter of one ring of a positron tomograph has been constructed. The positron annihilation gamma rays are detected by polished plastic scintillators which direct scintillation light by internal reflection to optical fibers for transmission to the photo-multiplier tubes. By viewing each scintillator with four sets of optical fibers, the number of photomultipliers required for an eight ring tomograph with 1024 detectors per ring (2.4 mm wide detectors) can be reduced from 8192 to 288, and the cost of the tomograph reduced accordingly

  2. Quantitative multiphoton imaging

    Science.gov (United States)

    König, Karsten; Weinigel, Martin; Breunig, Hans Georg; Uchugonova, Aisada

    2014-02-01

    Certified clinical multiphoton tomographs for label-free multidimensional high-resolution in vivo imaging have been introduced to the market several years ago. Novel tomographs include a flexible 360° scan head attached to a mechanooptical arm for autofluorescence and SHG imaging as well as a CARS module. Non-fluorescent lipids and water, mitochondrial fluorescent NAD(P)H, fluorescent elastin, keratin, and melanin as well as SHG-active collagen can be imaged in vivo with submicron resolution in human skin. Sensitive and rapid detectors allow single photon counting and the construction of 3D maps where the number of detected photons per voxel is depicted. Intratissue concentration profiles from endogenous as well exogenous substances can be generated when the number of detected photons can be correlated with the number of molecules with respect to binding and scattering behavior. Furthermore, the skin ageing index SAAID based on the ratio elastin/collagen as well as the epidermis depth based on the onset of SHG generation can be determined.

  3. Image guidance quality assurance of a G4 CyberKnife robotic stereotactic radiosurgery system

    International Nuclear Information System (INIS)

    Pantelis, E; Antypas, C; Petrokokkinos, L

    2009-01-01

    The image guidance of a CyberKnife robotic radiosurgery system was quality controlled, including the overall performance of the target locating subsystem and the performance of the x-ray generators and flat panel digital cameras subcomponents. Accuracy and precision of the kV and exposure time settings of the x-ray generators, linearity of the x-ray output, spatial resolution and geometrical distortion of the acquired x-ray images were measured. Total accuracy and precision of the target locating subsystem in defining the position of an anthropomorphic head and neck phantom placed on treatment couch was also measured. Accuracy and precision of the kV as well as exposure time settings and linearity of the x-ray output were found within the acceptance limits suggested in diagnostic radiology. The acquired x-ray images were found to depict the shapes of the imaging objects without any geometrical distortion, being able to resolve differences in the features of imaging objects with critical frequency of 1.3 lp/mm and 1.5 lp/mm for camera A and B, respectively. Total target locating system accuracy was found within 0.2 mm and 0.2 deg. in translations and rotations, respectively. Corresponding precision was found lower than 0.5%. These findings render the target locating subsystem of the CyberKnife capable of accurately registering the patient to treatment position and monitoring patient's movement during treatment delivery.

  4. An original acquisition chain for the TOHR High Resolution Tomograph[OASIS]; Conception d'une chaine d'acqusition originale pour le Tomographe Haute Resolution TOHR

    Energy Technology Data Exchange (ETDEWEB)

    Pinot, Laurent [Institut de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-04-02

    The framework of this work is part of a new approach of emission tomography adapted to small animals. The principle of our tomographic system TOHR (French acronym for High Resolution Tomograph) is based on the use of large solid angle and high resolution focusing collimators each mounted in front of a detection module of high efficiency. With a first-generation acquisition chain we were able to characterize TOHR, however, to take fully advantage of the TOHR possibilities, a completely new acquisition scheme had to be designed. This system, being the main topic of this work, makes use of temporal information. The detection of a particle that entered the detector is translated into temporal logical signals. These signals pass into a time coding circuitry and the coded results are transferred in a digital processor. According to the initial terms of delivery, the developed acquisition chain steers the detection of events dependent on the deposited energy and time of arrival. The latter is done by coincidence measurements. All elements are mounted on a special board included into a PC unit and a dedicated program controls the whole system. First experiments showed up the interest of the new acquisition unit for other application in physics or medical imaging.

  5. MO-DE-202-00: Image-Guided Interventions: Advances in Intraoperative Imaging, Guidance, and An Emerging Role for Medical Physics in Surgery

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

  6. Experience of computed tomographic myelography and discography in cervical problem

    Energy Technology Data Exchange (ETDEWEB)

    Nakatani, Shigeru; Yamamoto, Masayuki; Uratsuji, Masaaki; Suzuki, Kunio; Matsui, Eigo [Hyogo Prefectural Awaji Hospital, Sumoto, Hyogo (Japan); Kurihara, Akira

    1983-06-01

    CTM (computed tomographic myelography) was performed on 15 cases of cervical lesions, and on 5 of them, CTD (computed tomographic discography) was also made. CTM revealed the intervertebral state, and in combination with CTD, providing more accurate information. The combined method of CTM and CTD was useful for soft disc herniation.

  7. Tomographic findings of acute pulmonary toxoplasmosis in immunocompetent patients.

    Science.gov (United States)

    de Souza Giassi, Karina; Costa, Andre Nathan; Apanavicius, Andre; Teixeira, Fernando Bin; Fernandes, Caio Julio Cesar; Helito, Alfredo Salim; Kairalla, Ronaldo Adib

    2014-11-25

    Toxoplasmosis is one of the most common human zoonosis, and is generally benign in most of the individuals. Pulmonary involvement is common in immunocompromised subjects, but very rare in immunocompetents and there are scarce reports of tomographic findings in the literature. The aim of the study is to describe three immunocompetent patients diagnosed with acute pulmonary toxoplasmosis and their respective thoracic tomographic findings. Acute toxoplasmosis was diagnosed according to the results of serological tests suggestive of recent primary infection and the absence of an alternative etiology. From 2009 to 2013, three patients were diagnosed with acute respiratory failure secondary to acute toxoplasmosis. The patients were two female and one male, and were 38, 56 and 36 years old. Similarly they presented a two-week febrile illness and progressive dyspnea before admission. Laboratory tests demonstrated lymphocytosis, slight changes in liver enzymes and high inflammatory markers. Tomographic findings were bilateral smooth septal and peribronchovascular thickening (100%), ground-glass opacities (100%), atelectasis (33%), random nodules (33%), lymph node enlargement (33%) and pleural effusion (66%). All the patients improved their symptoms after treatment, and complete resolution of tomographic findings were found in the followup. These cases provide a unique description of the presentation and evolution of pulmonary tomographic manifestations of toxoplasmosis in immunocompetent patients. Toxoplasma pneumonia manifests with fever, dyspnea and a non-productive cough that may result in respiratory failure. In animal models, changes were described as interstitial pneumonitis with focal infiltrates of neutrophils that can finally evolve into a pattern of diffuse alveolar damage with focal necrosis. The tomographic findings are characterized as ground glass opacities, smooth septal and marked peribronchovascular thickening; and may mimic pulmonary congestion

  8. Experimental and theoretical analysis for improved microscope design of optical projection tomographic microscopy.

    Science.gov (United States)

    Coe, Ryan L; Seibel, Eric J

    2013-09-01

    We present theoretical and experimental results of axial displacement of objects relative to a fixed condenser focal plane (FP) in optical projection tomographic microscopy (OPTM). OPTM produces three-dimensional, reconstructed images of single cells from two-dimensional projections. The cell rotates in a microcapillary to acquire projections from different perspectives where the objective FP is scanned through the cell while the condenser FP remains fixed at the center of the microcapillary. This work uses a combination of experimental and theoretical methods to improve the OPTM instrument design.

  9. A positron tomograph with 600 BGO crystals and 2.6 mm resolution

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Huesman, R.H.; Cahoon, J.L.; Geyer, A.B.; Moses, W.W.; Uber, D.C.; Vuletich, T.; Budinger, T.F.

    1988-01-01

    The authors describe the imaging performance of the Donner 600-Crystal Positron Tomograph, a single 60 cm diam ring of 3 mm wide bismuth germanate (BGO) crystals coupled individually to 14 mm phototubes. With a pulse height threshold of 200 keV and a slice thickness of 5 mm, the sensitivity is 7024 events/sec per μCi/ml in a 20 cm cylinder of water. The measured rates for 18 μCi/ml are 95,000 trues/sec plus 20,000 random/sec. A 0.3 mm diam /sup 22/Na line source near the center of the tomograph has a circular point spread function (PSF) with a full-width at half-maximum (fwhm) of 2.6 mm. At 5 cm from the center the PSF is elliptical with a fwhm of 2.7 mm tangential x 3.2 mm radial. At 10 cm the PSF has a fwhm of 2.8 mm tangential x 4.8 mm radial. Attenuation data are accumulated with a 20 mCi /sup 68/Ge orbiting transmission source and 100 million coincident events are collected in 200 sec

  10. SU-E-J-185: A Systematic Review of Breathing Guidance in Radiation Oncology and Radiology

    International Nuclear Information System (INIS)

    Pollock, S; Keall, P; Keall, R

    2015-01-01

    Purpose: The advent of image-guided radiation therapy (IGRT) has led to dramatic improvements in the accuracy of treatment delivery in radiotherapy. Such advancements have highlighted the deleterious impact tumor motion can have on both image quality and radiation treatment delivery. One approach to reducing tumor motion is the use of breathing guidance systems during imaging and treatment. A review of such research had not yet been performed, it was therefore our aim to perform a systematic review of breathing guidance interventions within the fields of radiation oncology and radiology. Methods: Results of online database searches were filtered in accordance to a set of eligibility criteria. The search, filtration, and analysis of articles were conducted in accordance with the PRISMAStatement reporting standard (Preferred Reporting Items for Systematic reviews and Meta-Analyses) utilizing the PICOS approach (Participants, Intervention, Comparison, Outcome, Study design). Participants: Cancer patients, healthy volunteers. Intervention: Biofeedback breathing guidance systems. Comparison: No breathing guidance of the same breathing type. Outcome: Regularity of breathing signal and anatomic/tumor motion, medical image quality, radiation treatment margins and coverage, medical imaging and radiation treatment times. Study design: Quantitative and controlled prospective or retrospective trials. Results: The systematic search yielded a total of 479 articles, which were filtered down to 27 relevant articles in accordance to the eligibility criteria. The vast majority of investigated outcomes were significantly positively impacted by the use of breathing guidance; however, this was dependent upon the nature of the breathing guidance system and study design. In 25/27 studies significant improvements from the use of breathing guidance were observed. Conclusion: The results found here indicate that further clinical studies are warranted which quantify more comprehensively the

  11. SU-E-J-185: A Systematic Review of Breathing Guidance in Radiation Oncology and Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, S; Keall, P [University of Sydney, Sydney (Australia); Keall, R [Hammond Care Palliative and Supportive Care Service, Sydney, NSW (Australia)

    2015-06-15

    Purpose: The advent of image-guided radiation therapy (IGRT) has led to dramatic improvements in the accuracy of treatment delivery in radiotherapy. Such advancements have highlighted the deleterious impact tumor motion can have on both image quality and radiation treatment delivery. One approach to reducing tumor motion is the use of breathing guidance systems during imaging and treatment. A review of such research had not yet been performed, it was therefore our aim to perform a systematic review of breathing guidance interventions within the fields of radiation oncology and radiology. Methods: Results of online database searches were filtered in accordance to a set of eligibility criteria. The search, filtration, and analysis of articles were conducted in accordance with the PRISMAStatement reporting standard (Preferred Reporting Items for Systematic reviews and Meta-Analyses) utilizing the PICOS approach (Participants, Intervention, Comparison, Outcome, Study design). Participants: Cancer patients, healthy volunteers. Intervention: Biofeedback breathing guidance systems. Comparison: No breathing guidance of the same breathing type. Outcome: Regularity of breathing signal and anatomic/tumor motion, medical image quality, radiation treatment margins and coverage, medical imaging and radiation treatment times. Study design: Quantitative and controlled prospective or retrospective trials. Results: The systematic search yielded a total of 479 articles, which were filtered down to 27 relevant articles in accordance to the eligibility criteria. The vast majority of investigated outcomes were significantly positively impacted by the use of breathing guidance; however, this was dependent upon the nature of the breathing guidance system and study design. In 25/27 studies significant improvements from the use of breathing guidance were observed. Conclusion: The results found here indicate that further clinical studies are warranted which quantify more comprehensively the

  12. Tomographic sensing and localization of fluorescently labeled circulating cells in mice in vivo

    International Nuclear Information System (INIS)

    Zettergren, Eric; Swamy, Tushar; Niedre, Mark; Runnels, Judith; Lin, Charles P

    2012-01-01

    Sensing and enumeration of specific types of circulating cells in small animals is an important problem in many areas of biomedical research. Microscopy-based fluorescence in vivo flow cytometry methods have been developed previously, but these are typically limited to sampling of very small blood volumes, so that very rare circulating cells may escape detection. Recently, we described the development of a ‘diffuse fluorescence flow cytometer’ (DFFC) that allows sampling of much larger blood vessels and therefore circulating blood volumes in the hindlimb, forelimb or tail of a mouse. In this work, we extend this concept by developing and validating a method to tomographically localize circulating fluorescently labeled cells in the cross section of a tissue simulating optical flow phantom and mouse limb. This was achieved using two modulated light sources and an array of six fiber-coupled detectors that allowed rapid, high-sensitivity acquisition of full tomographic data sets at 10 Hz. These were reconstructed into two-dimensional cross-sectional images using Monte Carlo models of light propagation and the randomized algebraic reconstruction technique. We were able to obtain continuous images of moving cells in the sample cross section with 0.5 mm accuracy or better. We first demonstrated this concept in limb-mimicking optical flow photons with up to four flow channels, and then in the tails of mice with fluorescently labeled multiple myeloma cells. This approach increases the overall diagnostic utility of our DFFC instrument. (paper)

  13. Preparation and tomographic reconstruction of an arbitrary single-photon path qubit

    International Nuclear Information System (INIS)

    Baek, So-Young; Kim, Yoon-Ho

    2011-01-01

    We report methods for preparation and tomographic reconstruction of an arbitrary single-photon path qubit. The arbitrary single-photon path qubit is prepared losslessly by passing the heralded single-photon state from spontaneous parametric down-conversion through variable beam splitter. Quantum state tomography of the single-photon path qubit is implemented by introducing path-projection measurements based on the first-order single-photon quantum interference. Using the state preparation and path-projection measurements methods for the single-photon path qubit, we demonstrate preparation and complete tomographic reconstruction of the single-photon path qubit with arbitrary purity. -- Highlights: → We report methods for preparation and tomographic reconstruction of an arbitrary single-photon path qubit. → We implement path-projection measurements based on the first-order single-photon quantum interference. → We demonstrate preparation and complete tomographic reconstruction of the single-photon path qubit with arbitrary purity.

  14. Stereoscopic Integrated Imaging Goggles for Multimodal Intraoperative Image Guidance.

    Directory of Open Access Journals (Sweden)

    Christopher A Mela

    Full Text Available We have developed novel stereoscopic wearable multimodal intraoperative imaging and display systems entitled Integrated Imaging Goggles for guiding surgeries. The prototype systems offer real time stereoscopic fluorescence imaging and color reflectance imaging capacity, along with in vivo handheld microscopy and ultrasound imaging. With the Integrated Imaging Goggle, both wide-field fluorescence imaging and in vivo microscopy are provided. The real time ultrasound images can also be presented in the goggle display. Furthermore, real time goggle-to-goggle stereoscopic video sharing is demonstrated, which can greatly facilitate telemedicine. In this paper, the prototype systems are described, characterized and tested in surgeries in biological tissues ex vivo. We have found that the system can detect fluorescent targets with as low as 60 nM indocyanine green and can resolve structures down to 0.25 mm with large FOV stereoscopic imaging. The system has successfully guided simulated cancer surgeries in chicken. The Integrated Imaging Goggle is novel in 4 aspects: it is (a the first wearable stereoscopic wide-field intraoperative fluorescence imaging and display system, (b the first wearable system offering both large FOV and microscopic imaging simultaneously,

  15. A tomographic image of upper crustal structure using P and S wave seismic refraction data in the southern granulite terrain (SGT), India

    Science.gov (United States)

    Rajendra Prasad, B.; Behera, Laxmidhar; Rao, P. Koteswara

    2006-07-01

    We present a 2-D tomographic P and S wave velocity (Vp and Vs) image with Vp/Vs ratios along N-S trending 220 km long deep seismic profile acquired in 2005, which traverses across major shear and tectonically disturbed zones in southern granulite terrain (SGT), India. The 2-D velocity model constrained down to maximum 8 km depth shows velocity anomalies (>0.2 km/s) beneath major shear zones with good spatial resolution (>0.05 km/s). The presence of high Vp (6.3-6.5 km/s), Vs (3.5-3.8 km/s), Vp/Vs (>1.75) and Poisson's ratio (0.25-0.29) indicate significant compositional changes of rocks at shallow depths (0.5 to 8 km) reveal rapid crustal exhumation of mid to lower crustal rocks. This crustal exhumation could be responsible due to Pan-African tectonothermal activity during Neoproterozoic period.

  16. Computed tomographic findings of intracranial gliosis

    International Nuclear Information System (INIS)

    Weisberg, L.

    1981-01-01

    The clinical and computed tomographic (CT) findings in eight patients with pathological evidence of cerebral gliosis are analyzed. CT findings do not permit differentiation of gliosis from other neoplastic and non-neoplastic conditions. (orig.)

  17. Chest imaging with dual-energy substraction digital tomosynthesis

    International Nuclear Information System (INIS)

    Sone, S.; Kasuga, T.; Sakai, F.; Hirano, H.; Kubo, K.; Morimoto, M.; Takemura, K.; Hosoba, M.

    1993-01-01

    Dual-energy subtraction digital tomosynthesis with pulsed X-ray and rapid kV switching was used to examine calcifications in pulmonary lesions. The digital tomosynthesis system used included a conventional fluororadiographic TV unit with linear tomographic capabilities, a high resolution videocamera, and an image processing unit. Low-voltage, high voltage, and soft tissue subtracted or bone subtracted tomograms of any desired layer height were reconstructed from the image data acquired during a single tomographic swing. Calcifications, as well as their characteristics and distribution in pulmonary lesions, were clearly shown. The images also permitted discrimination of calcifications from dense fibrotic lesions. This technique was effective in demonstrating calcifications together with a solitary mass or disseminated nodules. (orig.)

  18. Established rheumatoid arthritis - new imaging modalities

    DEFF Research Database (Denmark)

    McQueen, Fiona M; Østergaard, Mikkel

    2007-01-01

    New imaging modalities are assuming an increasingly important role in the investigation and management of rheumatoid arthritis. It is now possible to obtain information about all tissues within the joint in three dimensions using tomographic techniques such as magnetic resonance imaging (MRI...

  19. SU-C-209-07: Phantoms for Digital Breast Tomosynthesis Imaging System Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, D; Liu, Y [Medical College of Wisconsin, Milwaukee, WI (United States)

    2016-06-15

    Purpose: Digital Breast Tomosynthesis (DBT) is gaining importance in breast imaging. There is a need for phantoms that can be used for image evaluation and comparison. Existing commercially available phantoms for DBT are expensive and may lack clinically relevant test objects. The purpose of this study is to develop phantoms for DBT evaluation. Methods Four phantoms have been designed and constructed to assess the image quality (IQ) of two DBT systems. The first contains a spiral of 0.3 mm SiC beads in gelatin to measure the tomographic slice thickness profile and uniformity of coverage in a series of tomographic planes. The second contains simulated tumors inclined with respect to the phantom base to assess tomographic image quality. The third has a tilted array of discs with varying contrast and diameter. This phantom was imaged alone and in a stack of TE slabs giving 2 to 10 cm thickness. The fourth has a dual wedge of glandular and adipose simulating materials. One wedge contains discs with varying diameter and thickness; the other supports a mass with six simulated spicules of varying size and a cluster of simulated calcifications. The simulated glandular tissue material varies between 35 and 100% of the total thickness (5.5 cm). Results: All phantoms were scanned successfully. The best IQ comparison was achieved with the dual wedge phantom as demonstrated by the spiculated mass and calcifications. Images were evaluated by two radiologists and one physicist. The projection images and corresponding set of tomographic planes were comparable and the synthesized projection images were inferior to the projection images for both systems. Conclusion: Four phantoms were designed, constructed and imaged on two DBT systems. They successfully demonstrated performance differences between two systems, and between true and synthesized projection images. Future work will incorporate these designs into a single phantom.

  20. Electronics for the Donner 600-Crystal Positron Tomograph

    International Nuclear Information System (INIS)

    Cahoon, J.L.; Huesman, R.H.; Derenzo, S.E.; Geyer, A.B.; Uber, D.C.; Turko, B.T.; Budinger, T.F.

    1985-10-01

    The data acquisition system, designed for the Donner 600-Crystal Positron Tomograph, is described. Coincidence timing resolution of less than five nanoseconds full width at half maximum and data rates in excess of one million events per second are achieved by using high-speed emitter coupled logic circuits, first-in first-out memory to derandomize data flow, and parallel architecture to increase throughput. These data rates allow the acquisition of adequate transmission data in a reasonable amount of time. Good timing resolution minimizes accidental coincidences and permits data rates greater than 100,000 image-forming events per second for high-speed dynamic emission tomography. Additional scatter and accidental rejection are accomplished for transmission data by using an orbiting source and a look-up table for valid events. Calibration of this complex electronic system is performed automatically under computer control. 4 refs., 5 figs

  1. Original circuitry for TOHR tomograph

    International Nuclear Information System (INIS)

    Cuzon, J.C.; Pinot, L.

    1999-01-01

    Having industrialization in mind, a specific electronics for a high resolution tomograph is designed out of the usual standards of nuclear physics. All the information are converted in the time domain and a fast processor, in front of the data acquisition, carries out the time and energy coincidences. (authors)

  2. Techniques for Interventional MRI Guidance in Closed-Bore Systems.

    Science.gov (United States)

    Busse, Harald; Kahn, Thomas; Moche, Michael

    2018-02-01

    Efficient image guidance is the basis for minimally invasive interventions. In comparison with X-ray, computed tomography (CT), or ultrasound imaging, magnetic resonance imaging (MRI) provides the best soft tissue contrast without ionizing radiation and is therefore predestined for procedural control. But MRI is also characterized by spatial constraints, electromagnetic interactions, long imaging times, and resulting workflow issues. Although many technical requirements have been met over the years-most notably magnetic resonance (MR) compatibility of tools, interventional pulse sequences, and powerful processing hardware and software-there is still a large variety of stand-alone devices and systems for specific procedures only.Stereotactic guidance with the table outside the magnet is common and relies on proper registration of the guiding grids or manipulators to the MR images. Instrument tracking, often by optical sensing, can be added to provide the physicians with proper eye-hand coordination during their navigated approach. Only in very short wide-bore systems, needles can be advanced at the extended arm under near real-time imaging. In standard magnets, control and workflow may be improved by remote operation using robotic or manual driving elements.This work highlights a number of devices and techniques for different interventional settings with a focus on percutaneous, interstitial procedures in different organ regions. The goal is to identify technical and procedural elements that might be relevant for interventional guidance in a broader context, independent of the clinical application given here. Key challenges remain the seamless integration into the interventional workflow, safe clinical translation, and proper cost effectiveness.

  3. Design and performance of a new positron computed tomograph (P.C.T.) using the time-of-flight (T.O.F.) information

    International Nuclear Information System (INIS)

    Laval, M.; Allemand, R.; Bouvier, A.

    1982-09-01

    A new tomograph for positron imaging using the time of flight measurement is described. Fast CsF crystals are used in this first prototype. Compared to the classical reconstruction method, the results of adding this information is a substantial increase of sensitivity, a reduced random coincidence count rate, and slight decrease of a scatter contribution in the images. Further improvements in the T.O.F. accuracy can be expected in using faster crystals

  4. Fluorescence tomographic imaging of sentinel lymph node using near-infrared emitting bioreducible dextran nanogels

    Directory of Open Access Journals (Sweden)

    Li J

    2014-12-01

    nanoprobes for safe and noninvasive SLN mapping. Keywords: nanogel, disulfide, dextran, lymph node, tomographic imaging

  5. Automatic method detection of artifacts for control of tomographic uniformity on SPECT; Metodo automatico de dteccion de artefactos para el control de la uniformidad tomografica en SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Reynes Llompart, G.; Puchal, R.

    2013-07-01

    The objective of this work is the find an automatic method for the detection and classification of artifacts produced in tomographic uniformity, extracting the characteristics necessary to apply a classification algorithm using pattern recognition techniques. The method has been trained and validated with synthetic images and tested with real images. (Author)

  6. A positron tomograph with 600 BGO [bismuth germanate] crystals and 2.6 mm resolution

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Huesman, R.H.; Cahoon, J.L.; Geyer, A.B.; Moses, W.W.; Uber, D.C.; Vuletich, T.; Budinger, T.F.

    1987-10-01

    We describe the imaging performance of the Donner 600-Crystal Positron Tomograph, a single 600 cm diam ring of 3 mm wide bismuth germanate (BGO) crystals coupled individually to 14 mm phototubes. With a pulse height threshold of 200 keV and a slice thickness of 5 mm, the sensitivity is 7024 eventssec per μCiml in a 20 cm cyliner of water. The measured rates for 18 μCiml are 95,000 truessec plus 20,000 randomsec. A 0.3 mm diam 22 Na line source near the center of the tomograph has a circular point spread function (PSF) with a full-width at half-maximum (fwhm) of 2.6 mm. At 5 cm from the center the PSF is elliptical with a fwhm of 2.7 mm tangential /times/ 3.2 mm radial. At 10 cm the PSF has a fwhm of 2.8 mm tangential /times/ 4.8 mm radial. Attenuation data are accumulated with a 20 mCi 68 Ge orbiting transmission source and 100 million coincident events are collected in 200 sec. 20 refs., 9 figs., 5 tabs

  7. Comparison among tomographic reconstruction with limited data

    International Nuclear Information System (INIS)

    Oliveira, Eric F.; Dantas, Carlos C.; Vasconcelos, Daniel A.A.; Cadiz, Luis F.; Melo, Silvio B.

    2011-01-01

    Nowadays there is a continuing interest in applying computed tomography (CT) techniques in non-destructive testing and inspection of many industrial products. These applications of CT usually require a differentiated analysis when there are strong limitations in acquiring a sufficiently large amount of projection data. The use of a low number of tomographic data normally degrades the quality of the reconstructed image, highlighting the formation of artifacts and noise. This work investigates the reconstruction methods most commonly used (FBP, ART, SIRT, MART, SMART) and shows the performance of each one in this limited scenario. For this purpose, all methods were implemented and tested with a phantom of uniform density with well-known distribution, with measures of transmission of gamma radiation in a first generation CT scanner. The phantom is a concentric stainless steel tube coupled with a half - cylinder of aluminum. The measurements were made with an highest root mean square error, with the formation of visible artifacts. The artifacts are diminished but still visible in the ART and SIRT techniques, and the best performance was observed with the techniques MART and SMART. The technical superiority of these multiplicative methods is clearly seen in the reconstructed image quality, endorsing their application to situations of limited input data. (author)

  8. The establishment of enteral nutrition with minimally-invasive interventional procedure under endoscopic or imaging guidance

    International Nuclear Information System (INIS)

    Li Feng; Cheng Yingsheng

    2010-01-01

    For patients unable to get the necessary nutrition orally, a variety of techniques,including surgical way, to make gastrostomy with tube placement have been employed. For recent years, gastrostomy and tube placement with the help of endoscopic guidance or percutaneous interventional management has been developed, which is superior to surgical procedure in minimizing injuries, decreasing cost and reducing complications. In certain clinical situations, both endoscopic method and interventional method can be employed. This paper aims to make a comprehensive review of the indications, techniques and skills, advantages and disadvantages of both the endoscopy-guided and the imaging-guided percutaneous gastrojejunostomy for the establishment of enteral nutrition. (authors)

  9. Tomographic imaging of the cervical spine of horses

    International Nuclear Information System (INIS)

    Souza, L.P.; Machado, V.M.V.; Santos, R.V.; Evangelista, F.C.; Vulcano, L.C.

    2012-01-01

    The anatomy of the cervical spine of mature horses based on images obtained with a helical computed tomography examination performed on anatomic specimens was studied. Computed tomography was the diagnostic imaging method of choice and allowed three-dimensional reconstructions of images and other anatomical planes, such as coronal and sagittal. All images were acquired and evaluated in the filter and window to bone tissue. It was possible to demonstrate the anatomical differences and peculiarities of the normal vertebrae, particularly the occipito-atlantoaxial region, which has a higher incidence of changes to assist in the visualization of any change of the bone pattern on CT studies. (author)

  10. Imaging systems in nuclear medicine and image evaluation

    International Nuclear Information System (INIS)

    Beck, R.; Charleston, D.; Metz, C.; Tsui, B.

    1981-01-01

    A general computer code to simulate the imaging properties of existing and hypothetical imaging systems viewing realistic source distributions within non-uniform media. Such a code allows comparative evaluations of existing and hypothetical systems, and optimization of critical parameters of system design by maximizing the signal-to-noise ratio. To be most useful, such a code allows simulation of conventional scintillation scanners and cameras as well as single-photon and position tomographic systems

  11. Collimator trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    Jaszczak, Ronald J.

    1979-01-01

    An improved collimator is provided for a scintillation camera system that employs a detector head for transaxial tomographic scanning. One object of this invention is to significantly reduce the time required to obtain statistically significant data in radioisotope scanning using a scintillation camera. Another is to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a radiation source of known strength without sacrificing spatial resolution. A further object is to reduce the necessary scanning time without degrading the images obtained. The collimator described has apertures defined by septa of different radiation transparency. The septa are aligned to provide greater radiation shielding from gamma radiation travelling within planes perpendicular to the cranial-caudal axis and less radiation shielding from gamma radiation travelling within other planes. Septa may also define apertures such that the collimator provides high spatial resolution of gamma rays traveling within planes perpendicular to the cranial-caudal axis and directed at the detector and high radiation sensitivity to gamma radiation travelling other planes and indicated at the detector. (LL)

  12. Prototype volumetric ultrasound tomography image guidance system for prone stereotactic partial breast irradiation: proof-of-concept

    Science.gov (United States)

    Chiu, Tsuicheng D.; Parsons, David; Zhang, Yue; Hrycushko, Brian; Zhao, Bo; Chopra, Rajiv; Kim, Nathan; Spangler, Ann; Rahimi, Asal; Timmerman, Robert; Jiang, Steve B.; Lu, Weiguo; Gu, Xuejun

    2018-03-01

    Accurate dose delivery in stereotactic partial breast irradiation (S-PBI) is challenging because of the target position uncertainty caused by breast deformation, the target volume changes caused by lumpectomy cavity shrinkage, and the target delineation uncertainty on simulation computed tomography (CT) images caused by poor soft tissue contrast. We have developed a volumetric ultrasound tomography (UST) image guidance system for prone position S-PBI. The system is composed of a novel 3D printed rotation water tank, a patient-specific resin breast immobilization cup, and a 1D array ultrasound transducer. Coronal 2D US images were acquired in 5° increments over a 360° range, and planes were acquired every 2 mm in elevation. A super-compounding technique was used to reconstruct the image volume. The image quality of UST was evaluated with a BB-1 breast phantom and BioZorb surgical marker, and the results revealed that UST offered better soft tissue contrast than CT and similar image quality to MR. In the evaluated plane, the size and location of five embedded objects were measured and compared to MR, which is considered as the ground truth. Objects’ diameters and the distances between objects in UST differ by approximately 1 to 2 mm from those in MR, which showed that UST offers the image quality required for S-PBI. In future work we will develop a robotic system that will be ultimately implemented in the clinic.

  13. Accuracy and inter-observer variability of 3D versus 4D cone-beam CT based image-guidance in SBRT for lung tumors

    International Nuclear Information System (INIS)

    Sweeney, Reinhart A; Seubert, Benedikt; Stark, Silke; Homann, Vanessa; Müller, Gerd; Flentje, Michael; Guckenberger, Matthias

    2012-01-01

    To analyze the accuracy and inter-observer variability of image-guidance (IG) using 3D or 4D cone-beam CT (CBCT) technology in stereotactic body radiotherapy (SBRT) for lung tumors. Twenty-one consecutive patients treated with image-guided SBRT for primary and secondary lung tumors were basis for this study. A respiration correlated 4D-CT and planning contours served as reference for all IG techniques. Three IG techniques were performed independently by three radiation oncologists (ROs) and three radiotherapy technicians (RTTs). Image-guidance using respiration correlated 4D-CBCT (IG-4D) with automatic registration of the planning 4D-CT and the verification 4D-CBCT was considered gold-standard. Results were compared with two IG techniques using 3D-CBCT: 1) manual registration of the planning internal target volume (ITV) contour and the motion blurred tumor in the 3D-CBCT (IG-ITV); 2) automatic registration of the planning reference CT image and the verification 3D-CBCT (IG-3D). Image quality of 3D-CBCT and 4D-CBCT images was scored on a scale of 1–3, with 1 being best and 3 being worst quality for visual verification of the IGRT results. Image quality was scored significantly worse for 3D-CBCT compared to 4D-CBCT: the worst score of 3 was given in 19 % and 7.1 % observations, respectively. Significant differences in target localization were observed between 4D-CBCT and 3D-CBCT based IG: compared to the reference of IG-4D, tumor positions differed by 1.9 mm ± 0.9 mm (3D vector) on average using IG-ITV and by 3.6 mm ± 3.2 mm using IG-3D; results of IG-ITV were significantly closer to the reference IG-4D compared to IG-3D. Differences between the 4D-CBCT and 3D-CBCT techniques increased significantly with larger motion amplitude of the tumor; analogously, differences increased with worse 3D-CBCT image quality scores. Inter-observer variability was largest in SI direction and was significantly larger in IG using 3D-CBCT compared to 4D-CBCT: 0.6 mm versus 1.5 mm

  14. Accuracy and inter-observer variability of 3D versus 4D cone-beam CT based image-guidance in SBRT for lung tumors

    Directory of Open Access Journals (Sweden)

    Sweeney Reinhart A

    2012-06-01

    Full Text Available Abstract Background To analyze the accuracy and inter-observer variability of image-guidance (IG using 3D or 4D cone-beam CT (CBCT technology in stereotactic body radiotherapy (SBRT for lung tumors. Materials and methods Twenty-one consecutive patients treated with image-guided SBRT for primary and secondary lung tumors were basis for this study. A respiration correlated 4D-CT and planning contours served as reference for all IG techniques. Three IG techniques were performed independently by three radiation oncologists (ROs and three radiotherapy technicians (RTTs. Image-guidance using respiration correlated 4D-CBCT (IG-4D with automatic registration of the planning 4D-CT and the verification 4D-CBCT was considered gold-standard. Results were compared with two IG techniques using 3D-CBCT: 1 manual registration of the planning internal target volume (ITV contour and the motion blurred tumor in the 3D-CBCT (IG-ITV; 2 automatic registration of the planning reference CT image and the verification 3D-CBCT (IG-3D. Image quality of 3D-CBCT and 4D-CBCT images was scored on a scale of 1–3, with 1 being best and 3 being worst quality for visual verification of the IGRT results. Results Image quality was scored significantly worse for 3D-CBCT compared to 4D-CBCT: the worst score of 3 was given in 19 % and 7.1 % observations, respectively. Significant differences in target localization were observed between 4D-CBCT and 3D-CBCT based IG: compared to the reference of IG-4D, tumor positions differed by 1.9 mm ± 0.9 mm (3D vector on average using IG-ITV and by 3.6 mm ± 3.2 mm using IG-3D; results of IG-ITV were significantly closer to the reference IG-4D compared to IG-3D. Differences between the 4D-CBCT and 3D-CBCT techniques increased significantly with larger motion amplitude of the tumor; analogously, differences increased with worse 3D-CBCT image quality scores. Inter-observer variability was largest in SI direction and was

  15. Improving appropriate use of echocardiography and single-photon emission computed tomographic myocardial perfusion imaging: a continuous quality improvement initiative.

    Science.gov (United States)

    Johnson, Thomas V; Rose, Geoffrey A; Fenner, Deborah J; Rozario, Nigel L

    2014-07-01

    Appropriate use criteria for cardiovascular imaging have been published, but compliance in practice has been incomplete, with persistent high rates of inappropriate use. The aim of this study was to show the efficacy of a continuous quality improvement (CQI) initiative to favorably influence the appropriate use of outpatient transthoracic echocardiography and single-photon emission computed tomographic (SPECT) myocardial perfusion imaging (MPI) in a large cardiovascular practice. In this prospective study, a multiphase CQI initiative was implemented, and its impact on ordering patterns for outpatient transthoracic echocardiography and SPECT MPI was assessed. Between November and December 2010, a baseline analysis of the application of appropriate use criteria to indications for outpatient transthoracic echocardiographic studies (n = 203) and SPECT MPI studies (n = 205) was performed, with studies categorized as "appropriate," "inappropriate," "uncertain," or "unclassified." The CQI initiative was then begun, with (1) clinician education, including didactic lectures and case-based presentations with audience participation; (2) system changes in ordering processes, with redesigned image ordering forms; and (3) peer review and feedback. A follow-up analysis was then performed between June and August 2012, with categorization of indications for transthoracic echocardiographic studies (n = 206) and SPECT MPI studies (n = 206). At baseline, 73.9% of echocardiographic studies were categorized as appropriate, 16.7% as inappropriate, 5.9% as uncertain, and 3.4% as unclassified. Similarly, for SPECT MPI studies 71.7% were categorized as appropriate, 18.5% as inappropriate, 7.8% as uncertain, and 1.9% as unclassified. Separate analysis of the two most important categories, appropriate and inappropriate, demonstrated a significant improvement after the CQI initiative, with a 63% reduction in inappropriate echocardiographic studies (18.5% vs 6.9%, P = .0010) and a 46% reduction

  16. Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro-Computed Tomographic Study.

    Science.gov (United States)

    de Almeida, Bernardo Corrêa; Ormiga, Fabíola; de Araújo, Marcos César Pimenta; Lopes, Ricardo Tadeu; Lima, Inayá Corrêa Barbosa; dos Santos, Bernardo Camargo; Gusman, Heloisa

    2015-12-01

    The aim of this study was to make a 3-dimensional comparison of the canal transportation and changes in apical geometry using micro-computed tomographic imaging after canal preparation with K3 (SybronEndo, Orange, CA) and K3XF (SybronEndo) file systems. Twenty-eight mandibular molars were randomly divided into 2 groups according to the rotary system used in instrumentation: K3 or K3XF. The specimens were scanned by micro-computed tomographic imaging before and after instrumentation. Images before and after instrumentation from each group were compared with regard to canal volume, surface area, and structure model index (SMI) (paired t test, P instrumentation, the canals from each group were compared regarding the changes in volume, surface area, SMI, and canal transportation in the last 4 apical mm (t test, P Instrumentation with the 2 rotary systems significantly changed the canal volume, surface area, and SMI (P instrument types concerning these parameters (P > .05). There were no significant differences between the 2 groups with regard to canal transportation in the last 4 apical mm (P > .05). Both rotary systems showed adequate canal preparations with reduced values of canal transportation. Heat treatment did not influence changes in root canal geometry in the apical region. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Transsphenoidal pituitary resection with intraoperative MR guidance: preliminary results

    Science.gov (United States)

    Pergolizzi, Richard S., Jr.; Schwartz, Richard B.; Hsu, Liangge; Wong, Terence Z.; Black, Peter M.; Martin, Claudia; Jolesz, Ferenc A.

    1999-05-01

    The use of intraoperative MR image guidance has the potential to improve the precision, extent and safety of transsphenoidal pituitary resections. At Brigham and Women's Hospital, an open-bore configuration 0.5T MR system (SIGNA SP, GE Medical Systems, Milwaukee, WI) has been used to provide image guidance for nine transsphenoidal pituitary adenoma resections. The intraoperative MR system allowed the radiologist to direct the surgeon toward the sella turcica successfully while avoiding the cavernous sinus, optic chiasm and other sensitive structures. Imaging performed during the surgery monitored the extent of resection and allowed for removal of tumor beyond the surgeon's view in five cases. Dynamic MR imaging was used to distinguish residual tumor from normal gland and postoperative changes permitting more precise tumor localization. A heme-sensitive long TE gradient echo sequence was used to evaluate for the presence of hemorrhagic debris. All patients tolerated the procedure well without significant complications.

  18. Continuous monitoring of prostate position using stereoscopic and monoscopic kV image guidance

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, M. Tynan R.; Parsons, Dave D.; Robar, James L. [Department of Medical Physics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada and Nova Scotia Cancer Centre, QEII Health Science Centre, Halifax, Nova Scotia B3H 2Y9 (Canada)

    2016-05-15

    Purpose: To demonstrate continuous kV x-ray monitoring of prostate motion using both stereoscopic and monoscopic localizations, assess the spatial accuracy of these techniques, and evaluate the dose delivered from the added image guidance. Methods: The authors implemented both stereoscopic and monoscopic fiducial localizations using a room-mounted dual oblique x-ray system. Recently developed monoscopic 3D position estimation techniques potentially overcome the issue of treatment head interference with stereoscopic imaging at certain gantry angles. To demonstrate continuous position monitoring, a gold fiducial marker was placed in an anthropomorphic phantom and placed on the Linac couch. The couch was used as a programmable translation stage. The couch was programmed with a series of patient prostate motion trajectories exemplifying five distinct categories: stable prostate, slow drift, persistent excursion, transient excursion, and high frequency excursions. The phantom and fiducial were imaged using 140 kVp, 0.63 mAs per image at 1 Hz for a 60 s monitoring period. Both stereoscopic and monoscopic 3D localization accuracies were assessed by comparison to the ground-truth obtained from the Linac log file. Imaging dose was also assessed, using optically stimulated luminescence dosimeter inserts in the phantom. Results: Stereoscopic localization accuracy varied between 0.13 ± 0.05 and 0.33 ± 0.30 mm, depending on the motion trajectory. Monoscopic localization accuracy varied from 0.2 ± 0.1 to 1.1 ± 0.7 mm. The largest localization errors were typically observed in the left–right direction. There were significant differences in accuracy between the two monoscopic views, but which view was better varied from trajectory to trajectory. The imaging dose was measured to be between 2 and 15 μGy/mAs, depending on location in the phantom. Conclusions: The authors have demonstrated the first use of monoscopic localization for a room-mounted dual x-ray system. Three

  19. Robot-assisted endoscope guidance versus manual endoscope guidance in functional endonasal sinus surgery (FESS).

    Science.gov (United States)

    Eichhorn, Klaus Wolfgang; Westphal, Ralf; Rilk, Markus; Last, Carsten; Bootz, Friedrich; Wahl, Friedrich; Jakob, Mark; Send, Thorsten

    2017-10-01

    Having one hand occupied with the endoscope is the major disadvantage for the surgeon when it comes to functional endoscopic sinus surgery (FESS). Only the other hand is free to use the surgical instruments. Tiredness or frequent instrument changes can thus lead to shaky endoscopic images. We collected the pose data (position and orientation) of the rigid 0° endoscope and all the instruments used in 16 FESS procedures with manual endoscope guidance as well as robot-assisted endoscope guidance. In combination with the DICOM CT data, we tracked the endoscope poses and workspaces using self-developed tracking markers. All surgeries were performed once with the robot and once with the surgeon holding the endoscope. Looking at the durations required, we observed a decrease in the operating time because one surgeon doing all the procedures and so a learning curve occurred what we expected. The visual inspection of the specimens showed no damages to any of the structures outside the paranasal sinuses. Robot-assisted endoscope guidance in sinus surgery is possible. Further CT data, however, are desirable for the surgical analysis of a tracker-based navigation within the anatomic borders. Our marker-based tracking of the endoscope as well as the instruments makes an automated endoscope guidance feasible. On the subjective side, we see that RASS brings a relief for the surgeon.

  20. Survey of coded aperture imaging

    International Nuclear Information System (INIS)

    Barrett, H.H.

    1975-01-01

    The basic principle and limitations of coded aperture imaging for x-ray and gamma cameras are discussed. Current trends include (1) use of time varying apertures, (2) use of ''dilute'' apertures with transmission much less than 50%, and (3) attempts to derive transverse tomographic sections, unblurred by other planes, from coded images

  1. Magnetic particle imaging: from proof of principle to preclinical applications

    Science.gov (United States)

    Knopp, T.; Gdaniec, N.; Möddel, M.

    2017-07-01

    Tomographic imaging has become a mandatory tool for the diagnosis of a majority of diseases in clinical routine. Since each method has its pros and cons, a variety of them is regularly used in clinics to satisfy all application needs. Magnetic particle imaging (MPI) is a relatively new tomographic imaging technique that images magnetic nanoparticles with a high spatiotemporal resolution in a quantitative way, and in turn is highly suited for vascular and targeted imaging. MPI was introduced in 2005 and now enters the preclinical research phase, where medical researchers get access to this new technology and exploit its potential under physiological conditions. Within this paper, we review the development of MPI since its introduction in 2005. Besides an in-depth description of the basic principles, we provide detailed discussions on imaging sequences, reconstruction algorithms, scanner instrumentation and potential medical applications.

  2. Sacro-iliac joint arthrography in low back pain: feasibility of MRI guidance

    International Nuclear Information System (INIS)

    Ojala, Risto; Klemola, Rauli; Karppinen, Jaro; Sequeiros, Roberto Blanco; Tervonen, Osmo

    2001-01-01

    Objective: Evaluation of the feasibility of MR-guidance in sacro-iliac joint arthrography in patients whose low back pain is suspected to arise from the sacro-iliac joint (SIJ). Methods and patients: Twenty patients with low back pain underwent MR-guided sacro-iliac joint arthrography. Needles made from titanium (size 20 G, MDTech, USA) were used. For image guidance a 0.23T open-configuration C arm magnet (Proview, Marconi Medical Systems, USA) with special interventional hardware and software package (I-Path 200, Marconi Medical Systems) containing an MR compatible in-room console, large-screen (36'') display, optical navigator and accompanying software with dedicated sequences was used. No other image guidance modalities were used. Results: MR-guided SIJ arthrography was successfully performed in all twenty patients without complications. The optimal imaging sequence both for preoperative and intraoperative images was 3D-Gradient Echo sequence. The dispersal of the injected saline and anaesthetic could be determined inside the joint in all cases with heavily T2-weighted fast spin echo sequence. In the present study, 60% of the patients had significant reduction of pain after sacro-iliac joint arthrography and sacro-iliac joint was considered to be the source of patients low back pain in these patients. Conclusion: The present study shows that MR guidance with open configuration low field scanner is an accurate guiding method for sacro-iliac joint arthrography

  3. Data acquisition system for a positron tomograph using time-of-flight information

    International Nuclear Information System (INIS)

    Bertin, Francois.

    1981-12-01

    Progress in nuclear instrumentation has led to the development of scintillators much faster than the NaI crystal traditionally used in nuclear medicine. As a result it is now possible to measure time-of-flight, i.e. the time between the arrival of two γ rays emitted in coincidence on two detectors. With this extra information the β + annihilation site may be located. The introduction of time-of-flight in tomographic techniques called for research along two lines: - ''theoretical'' research leading to the creation of a new image reconstruction algorithm taking into account time-of-flight information - applied research leading to the development of an efficient measurement line and sophisticated data acquisition and processing electronics. This research has been carried out at LETI and is briefly outlined in chapter I. Chapter II shows how the introduction of time-of-flight and the modification of the reconstruction algorithm complicate the electronic and informatic equipment of the tomograph. Several acquisition and processing strategies are proposed, then the need to use an intermediate mass storage and hence to design a complex acquisition operator is demonstrated. Chapter III examines the structure of the acquisition operator and the resulting block diagram is presented in detail in chapter IV [fr

  4. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars.

    Science.gov (United States)

    Kurthukoti, Ameet J; Sharma, Pranjal; Swamy, Dinesh Francis; Shashidara, R; Swamy, Elaine Barretto

    2015-01-01

    Need for the study: The most important procedure for a successful endodontic treatment is the cleaning and shaping of the canal system. Understanding the internal anatomy of teeth provides valuable information to the clinician that would help him achieve higher clinical success during endodontic therapy. To evaluate by computed tomography-the internal anatomy of mandibular second primary molars with respect to the number of canals, cross-sectional shape of canals, cross-sectional area of canals and the root dentin thickness. A total of 31 mandibular second primary molars were subjected to computed-tomographic evaluation in the transverse plane, after mounting them in a prefabricated template. The images, thus, obtained were analyzed using De-winter Bio-wizard® software. All the samples demonstrated two canals in the mesial root, while majority of the samples (65.48%) demonstrated two canals in the distal root. The cross-sectional images of the mesial canals demonstrated a round shape, while the distal canals demonstrated an irregular shape. The root dentin thickness was highly reduced on the distal aspect of mesial and mesial aspect of distal canals. The mandibular second primary molars demonstrated wide variation and complexities in their internal anatomy. A thorough understanding of the complexity of the root canal system is essential for understanding the principles and problems of shaping and cleaning, determining the apical limits and dimensions of canal preparations, and for performing successful endodontic procedures. How to cite this article: Kurthukoti AJ, Sharma P, Swamy DF, Shashidara R, Swamy EB. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars. Int J Clin Pediatr Dent 2015;8(3):202-207.

  5. Noninvasive tomographic and velocimetric monitoring of multiphase flows

    International Nuclear Information System (INIS)

    Chaouki, J.; Dudukovic, M.P.

    1997-01-01

    A condensed review of recent advances accomplished in the development and the applications of noninvasive tomographic and velocimetric measurement techniques to multiphase flows and systems is presented. In recent years utilization of such noninvasive techniques has become widespread in many engineering disciplines that deal with systems involving two immiscible phases or more. Tomography provides concentration, holdup, or 2D or 3D density distribution of at least one component of the multiphase system, whereas velocimetry provides the dynamic features of the phase of interest such as the flow pattern, the velocity field, the 2D or 3D instantaneous movements, etc. The following review is divided into two parts. The first part summarizes progress and developments in flow imaging techniques using γ-ray and X-ray transmission tomography; X-ray radiography; neutron transmission tomography and radiography; positron emission tomography; X-ray diffraction tomography; nuclear magnetic resonance imaging; electrical capacitance tomography; optical tomography; microwave tomography; and ultrasonic tomography. The second part of the review summarizes progress and developments in the following velocimetry techniques: positron emission particle tracking; radioactive particle tracking; cinematography; laser-Doppler anemometry; particle image velocimetry; and fluorescence particle image velocimetry. The basic principles of tomography and velocimetry techniques are outlined, along with advantages and limitations inherent to each technique. The hydrodynamic and structural information yielded by these techniques is illustrated through a literature survey on their successful applications to the study of multiphase systems in such fields as particulate solids processes, fluidization engineering, porous media, pipe flows, transport within packed beds and sparged reactors, etc

  6. Application of tomographic techniques to two-dimensional surface analysis using the Harwell nuclear microprobe

    International Nuclear Information System (INIS)

    Huddleston, J.; Hutchinson, I.G.; Pierce, T.B.

    1983-01-01

    Nuclear methods of surface analysis are discussed briefly, and the circumstances are described in which a two-dimensional analysis of the sample surface is desirable to enable the surface composition to be mapped accurately. Tomographic techniques of data manipulation are outlined. Data acquisition in the present case is performed by moving the sample in a defined sequence of positions, at each of which analytical data are gathered by the proton microprobe. The method and equipment are outlined. Data processing leading to the reconstruction of the image is summarised. (U.K.)

  7. Present state and development of positron tomographs

    International Nuclear Information System (INIS)

    Allemand, R.; Gariod, R.; Laval, M.; Tournier, F.

    1979-01-01

    This document presents the main characteristics of positron tomographs and analyses the relative importance of the parameters to be taken into consideration in the design of a tomograph: on the one hand, the physical parameters linked to the measurement of the annihilation photons by time coincidence and, on the other, the geometrical and technological parameters of prime importance in minimizing the many spurious effects. The last part endeavours to show this sort of instrumentation has evolved. Using the results obtained in our laboratory by mathematical simulation, the expected advantages are presented on the picture quality of the time of flight measurement of annihilation photons. Where the physical aspects of this method are concerned, the advantage of using cesium fluoride as scintillator is demonstrated [fr

  8. Pulmonary Masses: Initial Results of Cone-beam CT Guidance with Needle Planning Software for Percutaneous Lung Biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Braak, Sicco J., E-mail: sjbraak@gmail.com [St. Antonius Hospital, Department of Radiology (Netherlands); Herder, Gerarda J. M., E-mail: j.herder@antoniusziekenhuis.nl [St. Antonius Hospital, Department of Pulmonology (Netherlands); Heesewijk, Johannes P. M. van, E-mail: j.heesewijk@antoniusziekenhuis.nl; Strijen, Marco J. L. van, E-mail: m.van.strijen@antoniusziekenhuis.nl [St. Antonius Hospital, Department of Radiology (Netherlands)

    2012-12-15

    Purpose: To evaluate the outcome of percutaneous lung biopsy (PLB) findings using cone-beam computed tomographic (CT) guidance (CBCT guidance) and compared to conventional biopsy guidance techniques. Methods: CBCT guidance is a stereotactic technique for needle interventions, combining 3D soft-tissue cone-beam CT, needle planning software, and real-time fluoroscopy. Between March 2007 and August 2010, we performed 84 Tru-Cut PLBs, where bronchoscopy did not provide histopathologic diagnosis. Mean patient age was 64.6 (range 24-85) years; 57 patients were men, and 25 were women. Records were prospectively collected for calculating sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. We also registered fluoroscopy time, room time, interventional time, dose-area product (DAP), and complications. Procedures were divided into subgroups (e.g., location, size, operator). Results: Mean lesion diameter was 32.5 (range 3.0-93.0) mm, and the mean number of samples per biopsy procedure was 3.2 (range 1-7). Mean fluoroscopy time was 161 (range 104-551) s, room time was 34 (range 15-79) min, mean DAP value was 25.9 (range 3.9-80.5) Gy{center_dot}cm{sup -2}, and interventional time was 18 (range 5-65) min. Of 84 lesions, 70 were malignant (83.3%) and 14 were benign (16.7%). Seven (8.3%) of the biopsy samples were nondiagnostic. All nondiagnostic biopsied lesions proved to be malignant during surgical resection. The outcome for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 90% (95% confidence interval [CI] 86-96), 100% (95% CI 82-100), 100% (95% CI 96-100), 66.7% (95% CI 55-83), and 91.7% (95% CI 86-96), respectively. Sixteen patients (19%) had minor and 2 (2.4%) had major complications. Conclusion: CBCT guidance is an effective method for PLB, with results comparable to CT/CT fluoroscopy guidance.

  9. The bar coil for NMR tomograph

    International Nuclear Information System (INIS)

    Bogorodzki, P.; Piatkowski, A.; Wasielewski, J.

    1995-01-01

    The bar coil (bi-planar) for the NMR tomograph, designed for medical diagnostics, has been described. The tests of coil shown that it generates good homogenous magnetic field in a big volume what results in improving of the signal-to-noise ratio

  10. Tomographic Reconstruction from a Few Views: A Multi-Marginal Optimal Transport Approach

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, I., E-mail: isabelle.abraham@cea.fr [CEA Ile de France (France); Abraham, R., E-mail: romain.abraham@univ-orleans.fr; Bergounioux, M., E-mail: maitine.bergounioux@univ-orleans.fr [Université d’Orléans, UFR Sciences, MAPMO, UMR 7349 (France); Carlier, G., E-mail: carlier@ceremade.dauphine.fr [CEREMADE, UMR CNRS 7534, Université Paris IX Dauphine, Pl. de Lattre de Tassigny (France)

    2017-02-15

    In this article, we focus on tomographic reconstruction. The problem is to determine the shape of the interior interface using a tomographic approach while very few X-ray radiographs are performed. We use a multi-marginal optimal transport approach. Preliminary numerical results are presented.

  11. Tomographic apparatus for reconstructing planar slices from non-absorbed and non-scattered radiation

    International Nuclear Information System (INIS)

    1980-01-01

    After briefly reviewing the history of computerised tomography, the deficiencies inherent in the various methods that have been adopted are discussed, e.g. slow data collection time, blurring of images and poor spatial resolution. Tomographic apparatus and processing methods are then described which can overcome these problems. The apparatus consists of a fan-shaped source of X-rays and a detector array which both rotate around the patient being examined. The data reduction process is derived in great detail; it is claimed that digital processing using convolution techniques is much faster than conventional methods. (U.K.)

  12. Work in progress. Flashing tomosynthesis: a tomographic technique for quantitative coronary angiography

    International Nuclear Information System (INIS)

    Woelke, H.; Hanrath, P.; Schlueter, M.; Bleifeld, W.; Klotz, E.; Weiss, H.; Waller, D.; von Weltzien, J.

    1982-01-01

    Flashing tomosynthesis, a procedure that consists of a recording step and a reconstruction step, facilitates the tomographic imaging of coronary arteries. In a comparative study 10 postmortem coronary arteriograms were examined with 35-mm cine technique and with flashing tomosynthesis. The degrees of stenosis found with both of these techniques were compared with morphometrically obtained values. A higher correlation coefficient existed for the degrees of stenosis obtained with tomosynthesis and morphometry (r=0.92, p<0.001, SEE=9%) than for those obtained with cine technique and morphometry (r=0.82, p<0.001, SEE=16%). The technique has also been successfully carried out in 5 patients with coronary artery disease

  13. The great imitator: IgG4 periaortitis masquerading as an acute aortic syndrome on computed tomographic angiography

    OpenAIRE

    Moore, Drew W.; Hansen, Neil J.; DiMaio, Dominick J.; Harrison, William L.

    2016-01-01

    We present the case of a 52-year-old woman who presented to the emergency department with chest and neck pain. Initial cervical spine magnetic resonance imaging shows an abnormal flow void in the left vertebral artery, which prompted a computed tomographic angiogram. This demonstrated a hyperdense thickened ascending aortic wall, which extended into the great vessel origins. Clinically and radiographically interpreted as an acute aortic syndrome and/or intramural hematoma, the patient underwe...

  14. Clinical studies of pigmented lesions in human skin by using a multiphoton tomograph

    Science.gov (United States)

    Balu, Mihaela; Kelly, Kristen M.; Zachary, Christopher B.; Harris, Ronald M.; Krasieva, Tatiana B.; König, Karsten; Tromberg, Bruce J.

    2013-02-01

    In vivo imaging of pigmented lesions in human skin was performed with a clinical multiphoton microscopy (MPM)-based tomograph (MPTflex, JenLab, Germany). Two-photon excited fluorescence was used for visualizing endogenous fluorophores such as NADH/FAD, keratin, melanin in the epidermal cells and elastin fibers in the dermis. Collagen fibers were imaged by second harmonic generation. Our study involved in vivo imaging of benign melanocytic nevi, atypical nevi and melanoma. The goal of this preliminary study was to identify in vivo the characteristic features and their frequency in pigmented lesions at different stages (benign, atypical and malignant) and to evaluate the ability of in vivo MPM to distinguish atypical nevi from melanoma. Comparison with histopathology was performed for the biopsied lesions. Benign melanocytic nevi were characterized by the presence of nevus cell nests at the epidermal-dermal junction. In atypical nevi, features such as lentiginous hyperplasia, acanthosis and architectural disorder were imaged. Cytological atypia was present in all the melanoma lesions imaged, showing the strongest correlation with malignancy. The MPM images demonstrated very good correlation with corresponding histological images, suggesting that MPM could be a promising tool for in vivo non-invasive pigmented lesion diagnosis, particularly distinguishing atypical nevi from melanoma.

  15. Tailoring four-dimensional cone-beam CT acquisition settings for fiducial marker-based image guidance in radiation therapy.

    Science.gov (United States)

    Jin, Peng; van Wieringen, Niek; Hulshof, Maarten C C M; Bel, Arjan; Alderliesten, Tanja

    2018-04-01

    Use of four-dimensional cone-beam CT (4D-CBCT) and fiducial markers for image guidance during radiation therapy (RT) of mobile tumors is challenging due to the trade-off among image quality, imaging dose, and scanning time. This study aimed to investigate different 4D-CBCT acquisition settings for good visibility of fiducial markers in 4D-CBCT. Using these 4D-CBCTs, the feasibility of marker-based 4D registration for RT setup verification and manual respiration-induced motion quantification was investigated. For this, we applied a dynamic phantom with three different breathing motion amplitudes and included two patients with implanted markers. Irrespective of the motion amplitude, for a medium field of view (FOV), marker visibility was improved by reducing the imaging dose per projection and increasing the number of projection images; however, the scanning time was 4 to 8 min. For a small FOV, the total imaging dose and the scanning time were reduced (62.5% of the dose using a medium FOV, 2.5 min) without losing marker visibility. However, the body contour could be missing for a small FOV, which is not preferred in RT. The marker-based 4D setup verification was feasible for both the phantom and patient data. Moreover, manual marker motion quantification can achieve a high accuracy with a mean error of [Formula: see text].

  16. Prospective electrocardiogram-gated axial 64-detector computed tomographic angiography vs retrospective gated helical technique to assess coronary artery bypass graft anastomosis. Comparison of image quality and patient radiation dose

    International Nuclear Information System (INIS)

    Machida, Haruhiko; Masukawa, Ai; Tanaka, Isao; Fukui, Rika; Suzuki, Kazufumi; Ueno, Eiko; Kodera, Kojiro; Nakano, Kiyoharu; Shen, Y.

    2010-01-01

    In the present study the effective dose and image quality at distal anastomoses were retrospectively compared between prospective electrocardiogram (ECG)-gated axial and retrospective ECG-gated helical techniques on 64-detector computed tomographic (CT) angiography following coronary artery bypass graft surgery. Following bypass surgery, 52 patients with a heart rate <65 beats/min underwent CT angiography: 26 patients each with prospective and retrospective ECG gating techniques. The effective dose was compared between the 2 groups using a 4-point scale (4, excellent; 1, poor) to grade the quality of curved multiplanar reformation images at distal anastomoses. Patient characteristics of the 2 groups were well matched, and the same CT scan parameters were used for both, except for the interval between surgery and CT examination, tube current, and image noise index. Image quality scores did not differ significantly (3.26±0.95 vs 3.35±0.87; P=0.63), but the effective dose was significantly lower in the prospective (7.3±1.8 mSv) than in the retrospective gating group (23.6±4.5 mSv) (P<0.0001). Following bypass surgery, 64-detector CT angiography using prospective ECG gating is superior to retrospective gating in limiting the radiation dose and maintaining the image quality of distal anastomoses. (author)

  17. Influence of using a single facial vein as outflow in full-face transplantation: A three-dimensional computed tomographic study.

    Science.gov (United States)

    Rodriguez-Lorenzo, Andres; Audolfsson, Thorir; Wong, Corrine; Cheng, Angela; Arbique, Gary; Nowinski, Daniel; Rozen, Shai

    2015-10-01

    The aim of this study was to evaluate the contribution of a single unilateral facial vein in the venous outflow of total-face allograft using three-dimensional computed tomographic imaging techniques to further elucidate the mechanisms of venous complications following total-face transplant. Full-face soft-tissue flaps were harvested from fresh adult human cadavers. A single facial vein was identified and injected distally to the submandibular gland with a radiopaque contrast (barium sulfate/gelatin mixture) in every specimen. Following vascular injections, three-dimensional computed tomographic venographies of the faces were performed. Images were viewed using TeraRecon Software (Teracon, Inc., San Mateo, CA, USA) allowing analysis of the venous anatomy and perfusion in different facial subunits by observing radiopaque filling venous patterns. Three-dimensional computed tomographic venographies demonstrated a venous network with different degrees of perfusion in subunits of the face in relation to the facial vein injection side: 100% of ipsilateral and contralateral forehead units, 100% of ipsilateral and 75% of contralateral periorbital units, 100% of ipsilateral and 25% of contralateral cheek units, 100% of ipsilateral and 75% of contralateral nose units, 100% of ipsilateral and 75% of contralateral upper lip units, 100% of ipsilateral and 25% of contralateral lower lip units, and 50% of ipsilateral and 25% of contralateral chin units. Venographies of the full-face grafts revealed better perfusion in the ipsilateral hemifaces from the facial vein in comparison with the contralateral hemifaces. Reduced perfusion was observed mostly in the contralateral cheek unit and contralateral lower face including the lower lip and chin units. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  18. Positron emission tomographic imaging of cardiac sympathetic innervation and function

    International Nuclear Information System (INIS)

    Goldstein, D.S.; Chang, P.C.; Eisenhofer, G.; Miletich, R.; Finn, R.; Bacher, J.; Kirk, K.L.; Bacharach, S.; Kopin, I.J.

    1990-01-01

    Sites of uptake, storage, and metabolism of [ 18 F]fluorodopamine and excretion of [ 18 F]fluorodopamine and its metabolites were visualized using positron emission tomographic (PET) scanning after intravenous injection of the tracer into anesthetized dogs. Radioactivity was concentrated in the renal pelvis, heart, liver, spleen, salivary glands, and gall bladder. Uptake of 18F by the heart resulted in striking delineation of the left ventricular myocardium. Pretreatment with desipramine markedly decreased cardiac positron emission, consistent with dependence of the heart on neuronal uptake (uptake-1) for removal of circulating catecholamines. In reserpinized animals, cardiac positron emission was absent within 30 minutes after injection of [ 18 F]-6-fluorodopamine, demonstrating that the emission in untreated animals was from radioactive labeling of the sympathetic storage vesicles. Decreased positron emission from denervated salivary glands confirmed that the tracer was concentrated in sympathetic neurons. Radioactivity in the gall bladder and urinary system depicted the hepatic and renal excretion of the tracer and its metabolites. Administration of tyramine or nitroprusside increased and ganglionic blockade with trimethaphan decreased the rate of loss of myocardial radioactivity. The results show that PET scanning after administration of [ 18 F]fluorodopamine can be used to visualize sites of sympathetic innervation, follow the metabolism and renal and hepatic excretion of catecholamines, and examine cardiac sympathetic function

  19. A new tomographic image on the Philippine Sea Slab beneath Tokyo - Implication to seismic hazard in the Tokyo metropolitan region -

    Science.gov (United States)

    Hirata, N.; Sakai, S.; Nakagawa, S.; Ishikawa, M.; Sato, H.; Kasahara, K.; Kimura, H.; Honda, R.

    2012-12-01

    region. Based on elastic wave velocities of rocks and minerals, we interpreted the tomographic images as petrologic images. Tomographic images revealed the presence of two stepwise velocity increase of the top layer of the subducting PSP slab. Rock velocity data reveals that subducting PSP crust transforms from blueschists to amphibolites at depth of 30km and amphibolites to eclogites at depth of 50km, which suggest that dehydration reactions occurs in subducting crust of basaltic compositions during prograde metamorphism and water is released from the subducting PSP crust. Tomograms show evidence for a low-velocity zone (LVZ) beneath the area just north of Tokyo bay. We interpret the LVZ as a serpentinized region in the forearc mantle of Honshu arc, resulting from hydration by water derived from subducting PSP crust. The P- and S-wave velocities within the serpentinized zone represent a degree of serpentinization as high as 10-40% for the LVZ with 20-km-long in noth-south and 90-km-long in east-west just above PSP, which is approximately eastern half or less of the previously estimated serpentinized area (Kamiya and Kobayashi, 2000). Because strength of the serpentinized preidotite is not large enough for brittle fracture, if the area is smaller than previously estimated, a possible area of the large thrusting fault on the upper surface of PSP can be larger than previously thought.

  20. Pressure spectra from single-snapshot tomographic PIV

    Science.gov (United States)

    Schneiders, Jan F. G.; Avallone, Francesco; Pröbsting, Stefan; Ragni, Daniele; Scarano, Fulvio

    2018-03-01

    The power spectral density and coherence of temporal pressure fluctuations are obtained from low-repetition-rate tomographic PIV measurements. This is achieved by extension of recent single-snapshot pressure evaluation techniques based upon the Taylor's hypothesis (TH) of frozen turbulence and vortex-in-cell (VIC) simulation. Finite time marching of the measured instantaneous velocity fields is performed using TH and VIC. Pressure is calculated from the resulting velocity time series. Because of the theoretical limitations, the finite time marching can be performed until the measured flow structures are convected out of the measurement volume. This provides a lower limit of resolvable frequency range. An upper limit is given by the spatial resolution of the measurements. Finite time-marching approaches are applied to low-repetition-rate tomographic PIV data of the flow past a straight trailing edge at 10 m/s. Reference results of the power spectral density and coherence are obtained from surface pressure transducers. In addition, the results are compared to state-of-the-art experimental data obtained from time-resolved tomographic PIV performed at 10 kHz. The time-resolved approach suffers from low spatial resolution and limited maximum acquisition frequency because of hardware limitations. Additionally, these approaches strongly depend upon the time kernel length chosen for pressure evaluation. On the other hand, the finite time-marching approaches make use of low-repetition-rate tomographic PIV measurements that offer higher spatial resolution. Consequently, increased accuracy of the power spectral density and coherence of pressure fluctuations are obtained in the high-frequency range, in comparison to the time-resolved measurements. The approaches based on TH and VIC are found to perform similarly in the high-frequency range. At lower frequencies, TH is found to underestimate coherence and intensity of the pressure fluctuations in comparison to time-resolved PIV