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Sample records for tomographic anthropomorphic models

  1. 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)

  2. 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.)

  3. Tomographic anthropomorphic models. Pt. 4. Organ doses for adults due to idealized external photon exposures

    CERN Document Server

    Zankl, M; Petoussi-Henss, N; Regulla, D

    2002-01-01

    The present report contains extensive tables and figures of conversion coefficients of organ and tissue equivalent dose, normalised to air kerma free in air for voxel anthropomorphic phantoms and for standard geometries of external photon radiation, estimated with Monte Carlo techniques. Four realistic adult voxel phantoms were used for the calculations, based on computed tomographic data of real people: three male phantoms, two of them being of average size, one representing a big man, and one female phantom of a tall and somewhat over weighted woman.

  4. Tomographic anthropomorphic models. Pt. 4. Organ doses for adults due to idealized external photon exposures

    International Nuclear Information System (INIS)

    Zankl, M.; Petoussi-Henss, N.; Fill, U.; Regulla, D.

    2002-01-01

    The present report contains extensive tables and figures of conversion coefficients of organ and tissue equivalent dose, normalised to air kerma free in air for voxel anthropomorphic phantoms and for standard geometries of external photon radiation, estimated with Monte Carlo techniques. Four realistic adult voxel phantoms were used for the calculations, based on computed tomographic data of real people: three male phantoms, two of them being of average size, one representing a big man, and one female phantom of a tall and somewhat over weighted woman. (orig.)

  5. Anthropomorphic thorax phantom for cardio-respiratory motion simulation in tomographic imaging

    Science.gov (United States)

    Bolwin, Konstantin; Czekalla, Björn; Frohwein, Lynn J.; Büther, Florian; Schäfers, Klaus P.

    2018-02-01

    Patient motion during medical imaging using techniques such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), or single emission computed tomography (SPECT) is well known to degrade images, leading to blurring effects or severe artifacts. Motion correction methods try to overcome these degrading effects. However, they need to be validated under realistic conditions. In this work, a sophisticated anthropomorphic thorax phantom is presented that combines several aspects of a simulator for cardio-respiratory motion. The phantom allows us to simulate various types of cardio-respiratory motions inside a human-like thorax, including features such as inflatable lungs, beating left ventricular myocardium, respiration-induced motion of the left ventricle, moving lung lesions, and moving coronary artery plaques. The phantom is constructed to be MR-compatible. This means that we can not only perform studies in PET, SPECT and CT, but also inside an MRI system. The technical features of the anthropomorphic thorax phantom Wilhelm are presented with regard to simulating motion effects in hybrid emission tomography and radiotherapy. This is supplemented by a study on the detectability of small coronary plaque lesions in PET/CT under the influence of cardio-respiratory motion, and a study on the accuracy of left ventricular blood volumes.

  6. Evaluation of CNN as anthropomorphic model observer

    Science.gov (United States)

    Massanes, Francesc; Brankov, Jovan G.

    2017-03-01

    Model observers (MO) are widely used in medical imaging to act as surrogates of human observers in task-based image quality evaluation, frequently towards optimization of reconstruction algorithms. In this paper, we explore the use of convolutional neural networks (CNN) to be used as MO. We will compare CNN MO to alternative MO currently being proposed and used such as the relevance vector machine based MO and channelized Hotelling observer (CHO). As the success of the CNN, and other deep learning approaches, is rooted in large data sets availability, which is rarely the case in medical imaging systems task-performance evaluation, we will evaluate CNN performance on both large and small training data sets.

  7. Modeling and control of an anthropomorphic robotic hand

    OpenAIRE

    Bensalah, Choukri

    2016-01-01

    Mención Europea en el título de doctor This thesis presents methods and tools for enabling the successful use of robotic hands. For highly dexterous and/or anthropomorphic robotic hands, these methods have to share some common goals, such as overcoming the potential complexity of the mechanical design and the ability of performing accurate tasks with low and efficient computational cost. A prerequisite for dexterity is to increase the workspace of the robotic hand. For th...

  8. Development of pathological anthropomorphic models using 3D modelling techniques for numerical dosimetry

    International Nuclear Information System (INIS)

    Costa, Kleber Souza Silva; Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson; Lima, Fernando Roberto de Andrade

    2011-01-01

    Computational exposure models can be used to estimate human body absorbed dose in a series of situations such as X-Ray exams for diagnosis, accidents and medical treatments. These models are fundamentally composed of an anthropomorphic simulator (phantom), an algorithm that simulates a radioactive source and a Monte Carlo Code. The accuracy of data obtained in the simulation is strongly connected to the adequacy of such simulation to the real situation. The phantoms are one of the key factors for the researcher manipulation. They are generally developed in supine position and its anatomy is patronized by compiled data from international institutions such as ICRP or ICRU. Several pathologies modify the structure of organs and body tissues. In order to measure how significant these alterations are, an anthropomorphic model was developed for this study: patient mastectomies. This model was developed using voxel phantom FASH and then coupled with EGSnrc Monte Carlo code

  9. Anthropomorphic Coding of Speech and Audio: A Model Inversion Approach

    Directory of Open Access Journals (Sweden)

    W. Bastiaan Kleijn

    2005-06-01

    Full Text Available Auditory modeling is a well-established methodology that provides insight into human perception and that facilitates the extraction of signal features that are most relevant to the listener. The aim of this paper is to provide a tutorial on perceptual speech and audio coding using an invertible auditory model. In this approach, the audio signal is converted into an auditory representation using an invertible auditory model. The auditory representation is quantized and coded. Upon decoding, it is then transformed back into the acoustic domain. This transformation converts a complex distortion criterion into a simple one, thus facilitating quantization with low complexity. We briefly review past work on auditory models and describe in more detail the components of our invertible model and its inversion procedure, that is, the method to reconstruct the signal from the output of the auditory model. We summarize attempts to use the auditory representation for low-bit-rate coding. Our approach also allows the exploitation of the inherent redundancy of the human auditory system for the purpose of multiple description (joint source-channel coding.

  10. 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)

  11. 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

  12. Rapid genetic algorithm optimization of a mouse computational model: Benefits for anthropomorphization of neonatal mouse cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Corina Teodora Bot

    2012-11-01

    Full Text Available While the mouse presents an invaluable experimental model organism in biology, its usefulness in cardiac arrhythmia research is limited in some aspects due to major electrophysiological differences between murine and human action potentials (APs. As previously described, these species-specific traits can be partly overcome by application of a cell-type transforming clamp (CTC to anthropomorphize the murine cardiac AP. CTC is a hybrid experimental-computational dynamic clamp technique, in which a computationally calculated time-dependent current is inserted into a cell in real time, to compensate for the differences between sarcolemmal currents of that cell (e.g., murine and the desired species (e.g., human. For effective CTC performance, mismatch between the measured cell and a mathematical model used to mimic the measured AP must be minimal. We have developed a genetic algorithm (GA approach that rapidly tunes a mathematical model to reproduce the AP of the murine cardiac myocyte under study. Compared to a prior implementation that used a template-based model selection approach, we show that GA optimization to a cell-specific model results in a much better recapitulation of the desired AP morphology with CTC. This improvement was more pronounced when anthropomorphizing neonatal mouse cardiomyocytes to human-like APs than to guinea pig APs. CTC may be useful for a wide range of applications, from screening effects of pharmaceutical compounds on ion channel activity, to exploring variations in the mouse or human genome. Rapid GA optimization of a cell-specific mathematical model improves CTC performance and may therefore expand the applicability and usage of the CTC technique.

  13. Voxel anthropomorphic phantoms: review of models used for ionising radiation dosimetry

    International Nuclear Information System (INIS)

    Lemosquet, A.; Carlan, L. de; Clairand, I.

    2003-01-01

    Computational anthropomorphic phantoms have been used since the 1970's for dosimetric calculations. Realistic geometries are required for this operation, resulting in the development of ever more accurate phantoms. Voxel phantoms, consisting of a set of small-volume elements, appeared towards the end of the 1980's, and significantly improved on the original mathematical models. Voxel phantoms are models of the human body, obtained using computed tomography (CT) or magnetic resonance images (MRI). These phantoms are an extremely accurate representation of the human anatomy. This article provides a review of the literature available on the development of these phantoms and their applications in ionising radiation dosimetry. The bibliographical study has shown that there is a wide range of phantoms, covering various characteristics of the general population in terms of sex, age or morphology, and that they are used in applications relating to all aspects of ionising radiation. (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. 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.

  16. Investigation of attenuation correction in SPECT using textural features, Monte Carlo simulations, and computational anthropomorphic models.

    Science.gov (United States)

    Spirou, Spiridon V; Papadimitroulas, Panagiotis; Liakou, Paraskevi; Georgoulias, Panagiotis; Loudos, George

    2015-09-01

    To present and evaluate a new methodology to investigate the effect of attenuation correction (AC) in single-photon emission computed tomography (SPECT) using textural features analysis, Monte Carlo techniques, and a computational anthropomorphic model. The GATE Monte Carlo toolkit was used to simulate SPECT experiments using the XCAT computational anthropomorphic model, filled with a realistic biodistribution of (99m)Tc-N-DBODC. The simulated gamma camera was the Siemens ECAM Dual-Head, equipped with a parallel hole lead collimator, with an image resolution of 3.54 × 3.54 mm(2). Thirty-six equispaced camera positions, spanning a full 360° arc, were simulated. Projections were calculated after applying a ± 20% energy window or after eliminating all scattered photons. The activity of the radioisotope was reconstructed using the MLEM algorithm. Photon attenuation was accounted for by calculating the radiological pathlength in a perpendicular line from the center of each voxel to the gamma camera. Twenty-two textural features were calculated on each slice, with and without AC, using 16 and 64 gray levels. A mask was used to identify only those pixels that belonged to each organ. Twelve of the 22 features showed almost no dependence on AC, irrespective of the organ involved. In both the heart and the liver, the mean and SD were the features most affected by AC. In the liver, six features were affected by AC only on some slices. Depending on the slice, skewness decreased by 22-34% with AC, kurtosis by 35-50%, long-run emphasis mean by 71-91%, and long-run emphasis range by 62-95%. In contrast, gray-level non-uniformity mean increased by 78-218% compared with the value without AC and run percentage mean by 51-159%. These results were not affected by the number of gray levels (16 vs. 64) or the data used for reconstruction: with the energy window or without scattered photons. The mean and SD were the main features affected by AC. In the heart, no other feature was

  17. Perception-Link Behavior Model: Supporting a Novel Operator Interface for a Customizable Anthropomorphic Telepresence Robot

    Directory of Open Access Journals (Sweden)

    William Gu

    2017-07-01

    Full Text Available A customizable anthropomorphic telepresence robot (CATR is an emerging medium that might have the highest degree of social presence among the existing mediated communication mediums. Unfortunately, there are problems with teleoperating a CATR, and these problems can deteriorate the gesture motion in a CATR. These problems are the disruption during decoupling, discontinuity due to the unstable transmission and jerkiness due to the reactive collision avoidance. From the review, none of the existing interfaces can simultaneously fix all of the problems. Hence, a novel framework with the perception-link behavior model (PLBM was proposed. The PLBM adopts the distributed spatiotemporal representation for all of its input signals. Equipping it with other components, the PLBM can solve the above problems with some limitations. For instance, the PLBM can retrieve missing modalities from its experience during decoupling. Next, the PLBM can handle up to a high level of drop rate in the network connection because it is dealing with gesture style and not pose. For collision prevention, the PLBM can tune the incoming gesture style so that the CATR can deliberately and smoothly avoid a collision. In summary, the framework consists of PLBM being able to increase the user’s presence on a CATR by synthesizing expressive user gestures.

  18. Comparison Between THOR Anthropomorphic Test Device and THOR Finite Element Model

    Science.gov (United States)

    Moore, Erik

    2014-01-01

    Extended time spent in reduced gravity can cause physiologic deconditioning of astronauts, reducing their ability to sustain excessive forces during dynamic phases of spaceflight such as landing. To make certain that the crew is safe during these phases, NASA must take caution when determining what types of landings are acceptable based on the accelerations applied to the astronaut. In order to test acceptable landings, various trials have been run accelerating humans, cadavers, and Anthropomorphic Test Devices (ATDs), or crash test dummies, at different acceleration and velocity rates on a sled testing platform. Using these tests, risks of injury will be created and metrics will be developed for the likelihood of injuries due to the acceleration. A finite element model (FEM) of the Test Device for Human Occupant Restraint (THOR) ATD has been developed that can simulate these test trials and others (Putnam, 2014), reducing the need for human and ATD testing. Additionally, this will give researchers a more effective way to test the accelerations and orientations encountered during spaceflight landings during design of new space vehicles for crewed missions. However, the FEM has not been proven and must be validated by comparing the forces, accelerations, and other measurements of all parts of the body between the physical tests already completed and computer simulated trials. The purpose of my research was to validate the FEM for the ATD using previously run trials with the physical THOR ATD.

  19. Use of realistic anthropomorphic models for calculation of radiation dose in nuclear medicine

    International Nuclear Information System (INIS)

    Stabin, Michael G.; Emmons, Mary A.; Fernald, Michael J.; Brill, A.B.; Segars, W.Paul

    2008-01-01

    Anthropomorphic phantoms based on simple geometric structures have been used in radiation dose calculations for many years. We have now developed a series of anatomically realistic phantoms representing adults and children using body models based on non-uniform rational B-spline (NURBS), with organ and body masses based on the reference values given in ICRP Publication 89. Age-dependent models were scaled and shaped to represent the reference individuals described in ICRP 89 (male and female adults, newborns, 1-, 5-, 10- and 15-year-olds), using a software tool developed in Visual C++. Voxel-based versions of these models were used with GEANT4 radiation transport codes for calculation of specific absorbed fractions (SAFs) for internal sources of photons and electrons, using standard starting energy values. Organ masses in the models were within a few % of ICRP reference masses, and physicians reviewed the models for anatomical realism. Development of individual phantoms was much faster than manual segmentation of medical images, and resulted in a very uniform standardized phantom series. SAFs were calculated on the Vanderbilt multi node computing network (ACCRE). Photon and electron SAFs were calculated for all organs in all models, and were compared to values from similar phantoms developed by others. Agreement was very good in most cases; some differences were seen, due to differences in organ mass and geometry. This realistic phantom series represents a possible replacement for the Cristy/Eckerman series of the 1980's. Both phantom sets will be included in the next release of the OLINDA/EXM personal computer code, and the new phantoms will be made generally available to the research community for other uses. Calculated radiation doses for diagnostic and therapeutic radiopharmaceuticals will be compared with previous values. (author)

  20. Computational anthropomorphic phantoms for radiation protection dosimetry: evolution and prospects

    International Nuclear Information System (INIS)

    Lee, Choonsik; Lee, Jaiki

    2006-01-01

    Computational anthropomorphic phantoms are computer models of human anatomy used in the calculation of radiation dose distribution in the human body upon exposure to a radiation source. Depending on the manner to represent human anatomy, they are categorized into two classes: stylized and tomographic phantoms. Stylized phantoms, which have mainly been developed at the Oak Ridge National Laboratory (ORNL), describe human anatomy by using simple mathematical equations of analytical geometry. Several improved stylized phantoms such as male and female adults, pediatric series, and enhanced organ models have been developed following the first hermaphrodite adult stylized phantom, Medical Internal Radiation Dose (MIRD)-5 phantom. Although stylized phantoms have significantly contributed to dosimetry calculation, they provide only approximations of the true anatomical features of the human body and the resulting organ dose distribution. An alternative class of computational phantom, the tomographic phantom, is based upon three-dimensional imaging techniques such as Magnetic Resonance (MR) imaging and Computed Tomography (CT). The tomographic phantoms represent the human anatomy with a large number of voxels that are assigned tissue type and organ identity. To date, a total of around 30 tomographic phantoms including male and female adults, pediatric phantoms, and even a pregnant female, have been developed and utilized for realistic radiation dosimetry calculation. They are based on MRI/CT images or sectional color photos from patients, volunteers or cadavers. Several investigators have compared tomographic phantoms with stylized phantoms, and demonstrated the superiority of tomographic phantoms in terms of realistic anatomy and dosimetry calculation. This paper summarizes the history and current status of both stylized and tomographic phantoms, including Korean computational phantoms. Advantages, limitations, and future prospects are also discussed

  1. MO-FG-209-05: Towards a Feature-Based Anthropomorphic Model Observer

    International Nuclear Information System (INIS)

    Avanaki, A.

    2016-01-01

    This symposium will review recent advances in the simulation methods for evaluation of novel breast imaging systems – the subject of AAPM Task Group TG234. Our focus will be on the various approaches to development and validation of software anthropomorphic phantoms and their use in the statistical assessment of novel imaging systems using such phantoms along with computational models for the x-ray image formation process. Due to the dynamic development and complex design of modern medical imaging systems, the simulation of anatomical structures, image acquisition modalities, and the image perception and analysis offers substantial benefits of reduced cost, duration, and radiation exposure, as well as the known ground-truth and wide variability in simulated anatomies. For these reasons, Virtual Clinical Trials (VCTs) have been increasingly accepted as a viable tool for preclinical assessment of x-ray and other breast imaging methods. Activities of TG234 have encompassed the optimization of protocols for simulation studies, including phantom specifications, the simulated data representation, models of the imaging process, and statistical assessment of simulated images. The symposium will discuss the state-of-the-science of VCTs for novel breast imaging systems, emphasizing recent developments and future directions. Presentations will discuss virtual phantoms for intermodality breast imaging performance comparisons, extension of the breast anatomy simulation to the cellular level, optimized integration of the simulated imaging chain, and the novel directions in the observer models design. Learning Objectives: Review novel results in developing and applying virtual phantoms for inter-modality breast imaging performance comparisons; Discuss the efforts to extend the computer simulation of breast anatomy and pathology to the cellular level; Summarize the state of the science in optimized integration of modules in the simulated imaging chain; Compare novel directions

  2. MO-FG-209-05: Towards a Feature-Based Anthropomorphic Model Observer

    Energy Technology Data Exchange (ETDEWEB)

    Avanaki, A.

    2016-06-15

    This symposium will review recent advances in the simulation methods for evaluation of novel breast imaging systems – the subject of AAPM Task Group TG234. Our focus will be on the various approaches to development and validation of software anthropomorphic phantoms and their use in the statistical assessment of novel imaging systems using such phantoms along with computational models for the x-ray image formation process. Due to the dynamic development and complex design of modern medical imaging systems, the simulation of anatomical structures, image acquisition modalities, and the image perception and analysis offers substantial benefits of reduced cost, duration, and radiation exposure, as well as the known ground-truth and wide variability in simulated anatomies. For these reasons, Virtual Clinical Trials (VCTs) have been increasingly accepted as a viable tool for preclinical assessment of x-ray and other breast imaging methods. Activities of TG234 have encompassed the optimization of protocols for simulation studies, including phantom specifications, the simulated data representation, models of the imaging process, and statistical assessment of simulated images. The symposium will discuss the state-of-the-science of VCTs for novel breast imaging systems, emphasizing recent developments and future directions. Presentations will discuss virtual phantoms for intermodality breast imaging performance comparisons, extension of the breast anatomy simulation to the cellular level, optimized integration of the simulated imaging chain, and the novel directions in the observer models design. Learning Objectives: Review novel results in developing and applying virtual phantoms for inter-modality breast imaging performance comparisons; Discuss the efforts to extend the computer simulation of breast anatomy and pathology to the cellular level; Summarize the state of the science in optimized integration of modules in the simulated imaging chain; Compare novel directions

  3. Development of pathological anthropomorphic models using 3D modelling techniques for numerical dosimetry; Desenvolvimento de modelos antropomorficos patologicos usando tecnicas de modelagem 3D para dosimetria numerica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Kleber Souza Silva [Faculdade Integrada de Pernambuco (FACIPE), Recife, PE (Brazil); Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil); Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-10-26

    Computational exposure models can be used to estimate human body absorbed dose in a series of situations such as X-Ray exams for diagnosis, accidents and medical treatments. These models are fundamentally composed of an anthropomorphic simulator (phantom), an algorithm that simulates a radioactive source and a Monte Carlo Code. The accuracy of data obtained in the simulation is strongly connected to the adequacy of such simulation to the real situation. The phantoms are one of the key factors for the researcher manipulation. They are generally developed in supine position and its anatomy is patronized by compiled data from international institutions such as ICRP or ICRU. Several pathologies modify the structure of organs and body tissues. In order to measure how significant these alterations are, an anthropomorphic model was developed for this study: patient mastectomies. This model was developed using voxel phantom FASH and then coupled with EGSnrc Monte Carlo code

  4. Software development for modeling positrons emission tomograph scanners

    International Nuclear Information System (INIS)

    Vieira, Igor Fagner

    2013-01-01

    The Geant4 Application for Tomographic Emission (GATE) is an international platform recognized and used to develop Computational Model Exposure (CME) in the context of Nuclear Medicine, although currently there are dedicated modules for applications in Radiotherapy and Computed Tomography (CT). GATE uses Monte Carlo (MC) methods, and has a scripting language of its own. The writing of scripts for simulation of a PET scanner in GATE involves a number of interrelated steps, and the accuracy of the simulation is dependent on the correct setup of the geometries involved, since the physical processes depend on them, as well as the modeling of electronic detectors in module Digitizer, for example. The manual implementation of this setup can be a source of errors, especially for users without experience in the field of simulations or without any previous knowledge of a programming language, and also due to the the fact that the modeling process in GATE still remains bounded to LINUX / UNIX based systems, an environment only familiar to a few. This becomes an obstacle for beginners and prevents the use of GATE by a larger number of users interested in optimizing their experiments and/or clinical protocols through a more accessible, fast and friendly application. The objective of this work is therefore to develop a user-friendly software for the modeling of Positron Emission Tomography called GUIGATE (Graphical User Interface for GATE), with specific modules dedicated to quality control in PET scanners. The results exhibit the features available in this first version of GUIGATE, present in a set of windows that allow users to create their input files, perform and display in real time the model and analyze its output file in a single environment, allowing so intuitively access the entire architecture of the GATE simulation and to CERN's data analyzer, the ROOT. (author)

  5. Tomographic models and seismotectonics of the Reggio Emilia region, Italy

    Science.gov (United States)

    Ciaccio, M. G.; Chiarabba, C.

    2002-02-01

    The aim of this study is to define the Vp and Vp/Vs structure of the fault zone ruptured by the M L 5.1 earthquake of October 15, 1996 which occurred near Reggio Emilia (central-northern Italy). A 1-month-long seismic sequence followed the mainshock and occurred in a small region along the outer border of the northern Apenninic belt, at depth ranging between 10 and 17 km. P- and S-wave arrival times from 304 aftershocks recorded by two local dense seismic arrays installed in the epicentral region have been inverted to obtain one- and three-dimensional velocity models by using state of the art local earthquake tomographic techniques. Velocity models and aftershock relocation help us to infer the seismotectonic of the region. Earthquakes originated along a NW-dipping backthrust of a NE-trending main thrust, composing the western part of the broad Ferrara Arc. A main high Vp and high Vp/Vs region delineates a pop-up structure in the center of the area. The high Vp/Vs within the pop-up structure supports the presence of a zone with increased pore pressure. The hypocentral depth of both mainshock and aftershocks is greater than those usually found for the main seismogenic regions of the Apenninic belt. P-wave velocity values in the seismogenic area, obtained by tomography, are compatible with rocks of the Mesozoic cover and suggest that seismicity occurred within the Mesozoic units stack at present by compressional tectonics.

  6. A comparison of newborn stylized and tomographic models for dose assessment in paediatric radiology

    International Nuclear Information System (INIS)

    Staton, R J; Pazik, F D; Nipper, J C; Williams, J L; Bolch, W E

    2003-01-01

    Establishment of organ doses from diagnostic and interventional examinations is a key component to quantifying the radiation risks from medical exposures and for formulating corresponding dose-reduction strategies. Radiation transport models of human anatomy provide a convenient method for simulating radiological examinations. At present, two classes of models exist: stylized mathematical models and tomographic voxel models. In the present study, organ dose comparisons are made for projection radiographs of both a stylized and a tomographic model of the newborn patient. Sixteen separate radiographs were simulated for each model at x-ray technique factors typical of newborn examinations: chest, abdomen, thorax and head views in the AP, PA, left LAT and right LAT projection orientation. For AP and PA radiographs of the torso (chest, abdomen and thorax views), the effective dose assessed for the tomographic model exceeds that for the stylized model with per cent differences ranging from 19% (AP abdominal view) to 43% AP chest view. In contrast, the effective dose for the stylized model exceeds that for the tomographic model for all eight lateral views including those of the head, with per cent differences ranging from 9% (LLAT chest view) to 51% (RLAT thorax view). While organ positioning differences do exist between the models, a major factor contributing to differences in effective dose is the models' exterior trunk shape. In the tomographic model, a more elliptical shape is seen thus providing for less tissue shielding for internal organs in the AP and PA directions, with corresponding increased tissue shielding in the lateral directions. This observation is opposite of that seen in comparisons of stylized and tomographic models of the adult

  7. 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

  8. 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

  9. Polymeric Materials Models in the Warrior Injury Assessment Manikin (WIAMan) Anthropomorphic Test Device (ATD) Tech Demonstrator

    Science.gov (United States)

    2017-01-01

    analytical model currently used by military vehicle analysts has been continuously updated to address the model’s inherent deficiencies and make the... model is a hyperelastic polymer model based upon statistical mechanics and the finite extensibility of a polymer chain.23 Its rheological ...ARL-TR-7927 ● JAN 2017 US Army Research Laboratory Polymeric Materials Models in the Warrior Injury Assessment Manikin (WIAMan

  10. Ratios between effective doses for tomographic and mathematician models due to internal exposure of photons

    International Nuclear Information System (INIS)

    Lima, F.R.A.; Kramer, R.; Khoury, H.J.; Santos, A.M.; Loureiro, E.C.M.

    2005-01-01

    The development of new and sophisticated Monte Carlo codes and tomographic human phantoms or voxels motivated the International Commission on Radiological Protection (ICRP) to revise the traditional models of exposure, which have been used to calculate effective dose coefficients for organs and tissues based on mathematician phantoms known as MIRD5. This paper shows the results of calculations using tomographic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel), recently developed by the authors as well as with the phantoms ADAM and EVA, of specific genres, type MIRD5, coupled to the EGS4 Monte Carlo and MCNP4C codes, for internal exposure with photons of energies between 10 keV and 4 MeV to several organs sources. Effective Doses for both models, tomographic and mathematician, will be compared separately as a function of the Monte Carlo code replacement, of compositions of human tissues and the anatomy reproduced through tomographs. The results indicate that for photon internal exposure, the use of models of exposure based in voxel, increases the values of effective doses up to 70% for some organs sources considered in this study, when compared with the corresponding results obtained with phantoms of MIRD-5 type

  11. 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)

  12. A semi-automatic method for developing an anthropomorphic numerical model of dielectric anatomy by MRI

    International Nuclear Information System (INIS)

    Mazzurana, M; Sandrini, L; Vaccari, A; Malacarne, C; Cristoforetti, L; Pontalti, R

    2003-01-01

    Complex permittivity values have a dominant role in the overall consideration of interaction between radiofrequency electromagnetic fields and living matter, and in related applications such as electromagnetic dosimetry. There are still some concerns about the accuracy of published data and about their variability due to the heterogeneous nature of biological tissues. The aim of this study is to provide an alternative semi-automatic method by which numerical dielectric human models for dosimetric studies can be obtained. Magnetic resonance imaging (MRI) tomography was used to acquire images. A new technique was employed to correct nonuniformities in the images and frequency-dependent transfer functions to correlate image intensity with complex permittivity were used. The proposed method provides frequency-dependent models in which permittivity and conductivity vary with continuity-even in the same tissue-reflecting the intrinsic realistic spatial dispersion of such parameters. The human model is tested with an FDTD (finite difference time domain) algorithm at different frequencies; the results of layer-averaged and whole-body-averaged SAR (specific absorption rate) are compared with published work, and reasonable agreement has been found. Due to the short time needed to obtain a whole body model, this semi-automatic method may be suitable for efficient study of various conditions that can determine large differences in the SAR distribution, such as body shape, posture, fat-to-muscle ratio, height and weight

  13. Use of VAP3D software for production and manipulation of synthetic radiographies of anthropomorphic models

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Lindeval Fernandes de, E-mail: lindeval@dmat.ufrr.b [Universidade Federal de Roraima (DMAT/UFRR), Boa Vista, RR (Brazil). Dept. de Matematica; Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Vieira, Jose W. [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil); Universidade de Pernambuco (EPP/UPE), Recife, PE (Brazil). Escola Politecnica de Pernambuco; Lima, Fernando R.A., E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Leal Neto, Viriato [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2011-07-01

    The Grupo de Dosimetria Numerica has developed exposure computational models (ECM) involving a Monte Carlo code and voxel phantoms to simulate various situations of internal and external exposure to ionizing radiation. Most analyses of the produced results are presented in tables and graphics formats. An alternative to this traditional way of analyzing results is to save voxels of Regions of Interest (ROI) of the phantom irradiated with information like the location of the voxel and the energy deposited in it during the simulation. Such information can be saved to a text file and later turned into 3D objects. In this paper the VAP3D software has been used to read text files produced in simulations using the ECM of DEN (Nuclear Energy Dept. - UFPE), converting them into binary files of the type RAW, and visualize them. In order to reflect the radiosensitivity of the organs and tissues suggested by ICRP-60, for conversion of text file to binary, of the energy deposited values are multiplied by the weighting factor of the tissue to which the voxel belongs. The result of the multiplication is normalized to the interval [0, 255]. The files transformed are referred herein as synthetic radiographies. In VAP3D software, it is possible to generate stacks from theses radiographies in transverse, sagittal and coronal directions. In order to illustrate the production of synthetic radiographies, some images are presented in this paper, and dosimetric results are obtained from a variety of ROIs of the phantoms of DEN for radiological exams. (author)

  14. Effects of body habitus on internal radiation dose calculations using the 5-year-old anthropomorphic male models

    Science.gov (United States)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-08-01

    Computational phantoms are commonly used in internal radiation dosimetry to assess the amount and distribution pattern of energy deposited in various parts of the human body from different internal radiation sources. Radiation dose assessments are commonly performed on predetermined reference computational phantoms while the argument for individualized patient-specific radiation dosimetry exists. This study aims to evaluate the influence of body habitus on internal dosimetry and to quantify the uncertainties in dose estimation correlated with the use of fixed reference models. The 5-year-old IT’IS male phantom was modified to match target anthropometric parameters, including body weight, body height and sitting height/stature ratio (SSR), determined from reference databases, thus enabling the creation of 125 5-year-old habitus-dependent male phantoms with 10th, 25th, 50th, 75th and 90th percentile body morphometries. We evaluated the absorbed fractions and the mean absorbed dose to the target region per unit cumulative activity in the source region (S-values) of F-18 in 46 source regions for the generated 125 anthropomorphic 5-year-old hybrid male phantoms using the Monte Carlo N-Particle eXtended general purpose Monte Carlo transport code and calculated the absorbed dose and effective dose of five 18F-labelled radiotracers for children of various habitus. For most organs, the S-value of F-18 presents stronger statistical correlations with body weight, standing height and sitting height than BMI and SSR. The self-absorbed fraction and self-absorbed S-values of F-18 and the absorbed dose and effective dose of 18F-labelled radiotracers present with the strongest statistical correlations with body weight. For 18F-Amino acids, 18F-Brain receptor substances, 18F-FDG, 18F-L-DOPA and 18F-FBPA, the mean absolute effective dose differences between phantoms of different habitus and fixed reference models are 11.4%, 11.3%, 10.8%, 13.3% and 11.4%, respectively. Total body

  15. Reasons between effective doses for tomographic and mathematical models due to external exposition by photons

    International Nuclear Information System (INIS)

    Kramer, R.; Khoury, H.J.; Yoriyaz, H.; Lima, F.R.A.; Loureiro, E.C.M.

    2005-01-01

    The development of Monte Carlo codes and new and sophisticated tomographic human models, or based on voxel, motivated the ICRP to propose a revision of the traditional exposition models, which have been used to calculate doses on organs and tissues using mathematical phantoms MIRD-type 5. This article presents calculations made with tomographic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel), recently developed and also, for comparison, with ADAM and Eve mathematician phantoms. All models were coupled to the EGS4 and MCNP4 codes for full body external irradiation by photons. It were simulated expositions AP, PA and rotational for energies varying between 10 keV and 10 MeV. The effective calculated doses were compared separately to evaluate: the replacement of the Monte Carlo code; the composition of the tissues and the replacement of tomographic phantoms by mathematical ones. Effective doses calculated results indicate that for external exposures by photons to introduce models based on voxels can cause a reduction of about 10% to the energies considered in this study

  16. Investigation of realistic PET simulations incorporating tumor patient's specificity using anthropomorphic models: Creation of an oncology database

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitroulas, Panagiotis; Efthimiou, Nikos; Nikiforidis, George C.; Kagadis, George C. [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 265 04 (Greece); Loudos, George [Department of Biomedical Engineering, Technological Educational Institute of Athens, Ag. Spyridonos Street, Egaleo GR 122 10, Athens (Greece); Le Maitre, Amandine; Hatt, Mathieu; Tixier, Florent; Visvikis, Dimitris [Medical Information Processing Laboratory (LaTIM), National Institute of Health and Medical Research (INSERM), 29609 Brest (France)

    2013-11-15

    Purpose: The GATE Monte Carlo simulation toolkit is used for the implementation of realistic PET simulations incorporating tumor heterogeneous activity distributions. The reconstructed patient images include noise from the acquisition process, imaging system's performance restrictions and have limited spatial resolution. For those reasons, the measured intensity cannot be simply introduced in GATE simulations, to reproduce clinical data. Investigation of the heterogeneity distribution within tumors applying partial volume correction (PVC) algorithms was assessed. The purpose of the present study was to create a simulated oncology database based on clinical data with realistic intratumor uptake heterogeneity properties.Methods: PET/CT data of seven oncology patients were used in order to create a realistic tumor database investigating the heterogeneity activity distribution of the simulated tumors. The anthropomorphic models (NURBS based cardiac torso and Zubal phantoms) were adapted to the CT data of each patient, and the activity distribution was extracted from the respective PET data. The patient-specific models were simulated with the Monte Carlo Geant4 application for tomography emission (GATE) in three different levels for each case: (a) using homogeneous activity within the tumor, (b) using heterogeneous activity distribution in every voxel within the tumor as it was extracted from the PET image, and (c) using heterogeneous activity distribution corresponding to the clinical image following PVC. The three different types of simulated data in each case were reconstructed with two iterations and filtered with a 3D Gaussian postfilter, in order to simulate the intratumor heterogeneous uptake. Heterogeneity in all generated images was quantified using textural feature derived parameters in 3D according to the ground truth of the simulation, and compared to clinical measurements. Finally, profiles were plotted in central slices of the tumors, across lines

  17. Investigation of realistic PET simulations incorporating tumor patient's specificity using anthropomorphic models: Creation of an oncology database

    International Nuclear Information System (INIS)

    Papadimitroulas, Panagiotis; Efthimiou, Nikos; Nikiforidis, George C.; Kagadis, George C.; Loudos, George; Le Maitre, Amandine; Hatt, Mathieu; Tixier, Florent; Visvikis, Dimitris

    2013-01-01

    Purpose: The GATE Monte Carlo simulation toolkit is used for the implementation of realistic PET simulations incorporating tumor heterogeneous activity distributions. The reconstructed patient images include noise from the acquisition process, imaging system's performance restrictions and have limited spatial resolution. For those reasons, the measured intensity cannot be simply introduced in GATE simulations, to reproduce clinical data. Investigation of the heterogeneity distribution within tumors applying partial volume correction (PVC) algorithms was assessed. The purpose of the present study was to create a simulated oncology database based on clinical data with realistic intratumor uptake heterogeneity properties.Methods: PET/CT data of seven oncology patients were used in order to create a realistic tumor database investigating the heterogeneity activity distribution of the simulated tumors. The anthropomorphic models (NURBS based cardiac torso and Zubal phantoms) were adapted to the CT data of each patient, and the activity distribution was extracted from the respective PET data. The patient-specific models were simulated with the Monte Carlo Geant4 application for tomography emission (GATE) in three different levels for each case: (a) using homogeneous activity within the tumor, (b) using heterogeneous activity distribution in every voxel within the tumor as it was extracted from the PET image, and (c) using heterogeneous activity distribution corresponding to the clinical image following PVC. The three different types of simulated data in each case were reconstructed with two iterations and filtered with a 3D Gaussian postfilter, in order to simulate the intratumor heterogeneous uptake. Heterogeneity in all generated images was quantified using textural feature derived parameters in 3D according to the ground truth of the simulation, and compared to clinical measurements. Finally, profiles were plotted in central slices of the tumors, across lines with

  18. 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

  19. Pulses processor modeling of the AR-PET tomograph

    International Nuclear Information System (INIS)

    Martinez Garbino, Lucio J.; Venialgo, E.; Estryk, Daniel S.; Verrastro, Claudio A.

    2009-01-01

    The detection of two gamma photons in time coincidence is the main process in Positron Emission Tomography. The front end processor estimate the energy and the time stamp of each incident gamma photon, the accuracy of such estimation improves the quality of contrast and resolution of final images. In this work a modeling tool of the full detection chain is described. Starting from stochastic generation of light photons, followed by photoelectrons time transit spread inside the photomultiplier, preamplifier response and digitalisation process were modeling and finally, several algorithms of Energy and Time Stamp estimation were evaluated and compared. (author)

  20. Comparison of kinetic models for data from a positron emission tomograph

    International Nuclear Information System (INIS)

    Coxson, P.G.; Huesman, R.H.; Lim, S.; Klein, G.J.; Reutter, B.W.; Budinger, T.F.

    1995-01-01

    The purpose of this research was to compare a physiological model of 82 Rb in the myocardium with two reduced order models with regard to their ability to assess physiological parameters of diagnostic significance. A three compartment physiological model of 82 Rb uptake in the myocardium was used to simulate kinetic region of interest data from a positron emission tomograph (PET). Simulations were generated for eight different blood flow rates reflecting the physiological range of interest. Two reduced order models which are commonly used with myocardial PET studies were fit to the simulated data and the parameters of the reduced order models were compared with the physiological parameters. Then all three models were fit to the simulated data with noise added. Monte Carlo simulations were used to evaluate and compare the diagnostic utility of the reduced order models

  1. 3D Printing of Plant Golgi Stacks from Their Electron Tomographic Models.

    Science.gov (United States)

    Mai, Keith Ka Ki; Kang, Madison J; Kang, Byung-Ho

    2017-01-01

    Three-dimensional (3D) printing is an effective tool for preparing tangible 3D models from computer visualizations to assist in scientific research and education. With the recent popularization of 3D printing processes, it is now possible for individual laboratories to convert their scientific data into a physical form suitable for presentation or teaching purposes. Electron tomography is an electron microscopy method by which 3D structures of subcellular organelles or macromolecular complexes are determined at nanometer-level resolutions. Electron tomography analyses have revealed the convoluted membrane architectures of Golgi stacks, chloroplasts, and mitochondria. But the intricacy of their 3D organizations is difficult to grasp from tomographic models illustrated on computer screens. Despite the rapid development of 3D printing technologies, production of organelle models based on experimental data with 3D printing has rarely been documented. In this chapter, we present a simple guide to creating 3D prints of electron tomographic models of plant Golgi stacks using the two most accessible 3D printing technologies.

  2. Experience of development and testing of a new model of an anthropomorphic radiodosimetric phantom of the human body ARDF-10 'Roman'

    International Nuclear Information System (INIS)

    Bruhov, R.E.; Finkel, F.V.

    2013-01-01

    In 2006-2010 by the commission of the Radiation and Nuclear Safety Authority in Finland applied scientific research and development of a new model of an anthropomorphic radio dosimetric phantom of the human body (the Phantom) were performed, after the development of the production technology and initial testing in 2010-2012 the first serial copy of the Phantom under the name ARDF-10 ROMAN was produced. The main application of the new model of the Phantom ARDF-10 ROMAN: - increase of the precision of calibration and implementation of the periodic monitoring of Whole body counters (WBC) equipment, standardization of measurement procedure for inter-laboratory comparisons of the incorporated activity. - metrological support of the development and implementation of new methods for human radiation spectrometry: identification of radionuclide content of incorporated activity in the human body; measurements of the activity of incorporated technogenic and natural radionuclides in the whole body and in the lungs; measurements of 90 Sr content in the bone tissue. Study of the mechanisms of the intake, distribution, accumulation and excretion of the radionuclides in the human body, such as: daughter products of 222 Rn decay in the respiratory tract, 241 Am, other transuranic elements; isotopes of iodine in the thyroid gland; radiopharmaceuticals administered to patients for diagnostic and medicinal purposes. Obtaining estimates of spatial-temporal distribution of individual internal exposure dose of a human. The result of the work of recent years has been the creation of hygienic safe standard sample of an anthropomorphic radio dosimetric phantom of the human body ARDF-10 ROMAN, consisting of 4 anthropometric models of body parts, which are independent assembly units (head phantom, neck phantom, torso phantom, knee phantom). Phantom models are made from simulators of bone, soft (muscle) and lungs biological tissue. The Phantom contains 28 separate elements. To the first

  3. Dosimetric comparison of the specific anthropomorphic mannequin (SAM) to 14 anatomical head models using a novel definition for the mobile phone positioning

    International Nuclear Information System (INIS)

    Kainz, Wolfgang; Christ, Andreas; Kellom, Tocher; Seidman, Seth; Nikoloski, Neviana; Beard, Brian; Kuster, Niels

    2005-01-01

    This paper presents new definitions for obtaining reproducible results in numerical phone dosimetry. Numerous numerical dosimetric studies have been published about the exposure of mobile phone users which concluded with conflicting results. However, many of these studies lack reproducibility due to shortcomings in the description of the phone positioning. The new approach was tested by two groups applying two different numerical program packages to compare the specific anthropomorphic mannequin (SAM) to 14 anatomically correct head models. A novel definition for the positioning of mobile phones next to anatomically correct head models is given along with other essential parameters to be reported. The definition is solely based on anatomical characteristics of the head. A simple up-to-date phone model was used to determine the peak spatial specific absorption rate (SAR) of mobile phones in SAM and in the anatomically correct head models. The results were validated by measurements. The study clearly shows that SAM gives a conservative estimate of the exposure in anatomically correct head models for head only tissue. Depending on frequency, phone position and head size the numerically calculated 10 g averaged SAR in the pinna can be up to 2.1 times greater than the peak spatial SAR in SAM. Measurements in small structures, such as the pinna, will significantly increase the uncertainty; therefore SAM was designed for SAR assessment in the head only. Whether SAM will provide a conservative value for the pinna depends on the pinna SAR limit of the safety standard considered

  4. SU-E-I-80: Quantification of Respiratory and Cardiac Motion Effect in SPECT Acquisitions Using Anthropomorphic Models: A Monte Carlo Simulation Study

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitroulas, P; Kostou, T; Kagadis, G [University of Patras, Rion, Ahaia (Greece); Loudos, G [Technological Educational Institute of Athens, Egaleo, Attika (Greece)

    2015-06-15

    Purpose: The purpose of the present study was to quantify, evaluate the impact of cardiac and respiratory motion on clinical nuclear imaging protocols. Common SPECT and scintigraphic scans are studied using Monte Carlo (MC) simulations, comparing the resulted images with and without motion. Methods: Realistic simulations were executed using the GATE toolkit and the XCAT anthropomorphic phantom as a reference model for human anatomy. Three different radiopharmaceuticals based on 99mTc were studied, namely 99mTc-MDP, 99mTc—N—DBODC and 99mTc—DTPA-aerosol for bone, myocardium and lung scanning respectively. The resolution of the phantom was set to 3.5 mm{sup 3}. The impact of the motion on spatial resolution was quantified using a sphere with 3.5 mm diameter and 10 separate time frames, in the ECAM modeled SPECT scanner. Finally, respiratory motion impact on resolution and imaging of lung lesions was investigated. The MLEM algorithm was used for data reconstruction, while the literature derived biodistributions of the pharmaceuticals were used as activity maps in the simulations. Results: FWHM was extracted for a static and a moving sphere which was ∼23 cm away from the entrance of the SPECT head. The difference in the FWHM was 20% between the two simulations. Profiles in thorax were compared in the case of bone scintigraphy, showing displacement and blurring of the bones when respiratory motion was inserted in the simulation. Large discrepancies were noticed in the case of myocardium imaging when cardiac motion was incorporated during the SPECT acquisition. Finally the borders of the lungs are blurred when respiratory motion is included resulting to a dislocation of ∼2.5 cm. Conclusion: As we move to individualized imaging and therapy procedures, quantitative and qualitative imaging is of high importance in nuclear diagnosis. MC simulations combined with anthropomorphic digital phantoms can provide an accurate tool for applications like motion correction

  5. 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.

  6. A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors.

    Science.gov (United States)

    Gao, Fei; Wang, Guo-Bao; Xiang, Zhan-Wang; Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

    2016-05-03

    This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors. This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed. The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups. The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors.

  7. Tomographic Validation of the AWSoM Model of the Inner Corona During Solar Minima

    Science.gov (United States)

    Manchester, W.; Vásquez, A. M.; Lloveras, D. G.; Mac Cormack, C.; Nuevo, F.; Lopez-Fuentes, M.; Frazin, R. A.; van der Holst, B.; Landi, E.; Gombosi, T. I.

    2017-12-01

    Continuous improvement of MHD three-dimensional (3D) models of the global solar corona, such as the Alfven Wave Solar Model (AWSoM) of the Space Weather Modeling Framework (SWMF), requires testing their ability to reproduce observational constraints at a global scale. To that end, solar rotational tomography based on EUV image time-series can be used to reconstruct the 3D distribution of the electron density and temperature in the inner solar corona (r used to validate steady-state 3D MHD simulations of the inner corona using the latest version of the AWSoM model. We perform the study for selected rotations representative of solar minimum conditions, when the global structure of the corona is more axisymmetric. We analyse in particular the ability of the MHD simulation to match the tomographic results across the boundary region between the equatorial streamer belt and the surrounding coronal holes. The region is of particular interest as the plasma flow from that zone is thought to be related to the origin of the slow component of the solar wind.

  8. Tomographic particle image velocimetry investigation of the flow in a modeled human carotid artery bifurcation

    Science.gov (United States)

    Buchmann, N. A.; Atkinson, C.; Jeremy, M. C.; Soria, J.

    2011-04-01

    Hemodynamic forces within the human carotid artery are well known to play a key role in the initiation and progression of vascular diseases such as atherosclerosis. The degree and extent of the disease largely depends on the prevailing three-dimensional flow structure and wall shear stress (WSS) distribution. This work presents tomographic PIV (Tomo-PIV) measurements of the flow structure and WSS in a physiologically accurate model of the human carotid artery bifurcation. The vascular geometry is reconstructed from patient-specific data and reproduced in a transparent flow phantom to demonstrate the feasibility of Tomo-PIV in a complex three-dimensional geometry. Tomographic reconstruction is performed with the multiplicative line-of-sight (MLOS) estimation and simultaneous multiplicative algebraic reconstruction (SMART) technique. The implemented methodology is validated by comparing the results with Stereo-PIV measurements in the same facility. Using a steady flow assumption, the measurement error and RMS uncertainty are directly inferred from the measured velocity field. It is shown that the measurement uncertainty increases for increasing light sheet thickness and increasing velocity gradients, which are largest near the vessel walls. For a typical volume depth of 6 mm (or 256 pixel), the analysis indicates that the velocity derived from 3D cross-correlation can be measured within ±2% of the maximum velocity (or ±0.2 pixel) near the center of the vessel and within ±5% (±0.6 pixel) near the vessel wall. The technique is then applied to acquire 3D-3C velocity field data at multiple axial locations within the carotid artery model, which are combined to yield the flow field and WSS in a volume of approximately 26 mm × 27 mm × 60 mm. Shear stress is computed from the velocity gradient tensor and a method for inferring the WSS distribution on the vessel wall is presented. The results indicate the presence of a complex and three-dimensional flow structure, with

  9. MO-E-17A-02: Incorporation of Contrast Medium Dynamics in Anthropomorphic Phantoms: The Advent of 5D XCAT Models

    Energy Technology Data Exchange (ETDEWEB)

    Sahbaee, P [NC State University, Raleigh, NC (United States); Samei, E [Duke University Medical Center, Durham, NC (United States); Segars, W [Duke University, Durham, NC (United States)

    2014-06-15

    Purpose: To develop a unique method to incorporate the dynamics of contrast-medium propagation into the anthropomorphic phantom, to generate a five-dimensional (5D) patient model for multimodality imaging studies. Methods: A compartmental model of blood circulation network within the body was embodied into an extended cardiac-torso (4D-XCAT) patient model. To do so, a computational physiologic model of the human cardiovascular system was developed which includes a series of compartments representing heart, vessels, and organs. Patient-specific cardiac output and blood volume were used as inputs influenced by the weight, height, age, and gender of the patient's model. For a given injection protocol and given XCAT model, the contrast-medium transmission within the body was described by a series of mass balance differential equations, the solutions to which provided the contrast enhancement-time curves for each organ; thereby defining the tissue materials including the contrastmedium within the XCAT model. A library of time-dependent organ materials was then defined. Each organ in each voxelized 4D-XCAT phantom was assigned to a corresponding time-varying material to create the 5D-XCAT phantom in which the fifth dimension is blood/contrast-medium within the temporal domain. Results: The model effectively predicts the time-varying concentration behavior of various contrast-medium administration in each organ for different patient models as function of patient size (weight/height) and different injection protocol factors (injection rate and pattern, iodine concentration or volume). The contrast enhanced XCAT patient models was developed based on the concentration of iodine as a function of time after injection. Conclusion: Majority of medical imaging systems take advantage of contrast-medium administration in terms of better image quality, the effect of which was ignored in previous optimization studies. The study enables a comprehensive optimization of contrast

  10. Construction of anthropomorphic hybrid, dual-lattice voxel models for optimizing image quality and dose in radiography

    Science.gov (United States)

    Petoussi-Henss, Nina; Becker, Janine; Greiter, Matthias; Schlattl, Helmut; Zankl, Maria; Hoeschen, Christoph

    2014-03-01

    In radiography there is generally a conflict between the best image quality and the lowest possible patient dose. A proven method of dosimetry is the simulation of radiation transport in virtual human models (i.e. phantoms). However, while the resolution of these voxel models is adequate for most dosimetric purposes, they cannot provide the required organ fine structures necessary for the assessment of the imaging quality. The aim of this work is to develop hybrid/dual-lattice voxel models (called also phantoms) as well as simulation methods by which patient dose and image quality for typical radiographic procedures can be determined. The results will provide a basis to investigate by means of simulations the relationships between patient dose and image quality for various imaging parameters and develop methods for their optimization. A hybrid model, based on NURBS (Non Linear Uniform Rational B-Spline) and PM (Polygon Mesh) surfaces, was constructed from an existing voxel model of a female patient. The organs of the hybrid model can be then scaled and deformed in a non-uniform way i.e. organ by organ; they can be, thus, adapted to patient characteristics without losing their anatomical realism. Furthermore, the left lobe of the lung was substituted by a high resolution lung voxel model, resulting in a dual-lattice geometry model. "Dual lattice" means in this context the combination of voxel models with different resolution. Monte Carlo simulations of radiographic imaging were performed with the code EGS4nrc, modified such as to perform dual lattice transport. Results are presented for a thorax examination.

  11. 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

  12. 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

  13. 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

  14. 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)

  15. Effects of body habitus on internal radiation dose calculations using the 5-year-old anthropomorphic male models

    DEFF Research Database (Denmark)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-01-01

    Xtended general purpose Monte Carlo transport code and calculated the absorbed dose and effective dose of five 18F-labelled radiotracers for children of various habitus. For most organs, the S-value of F-18 presents stronger statistical correlations with body weight, standing height and sitting height than BMI...... and SSR. The self-absorbed fraction and self-absorbed S-values of F-18 and the absorbed dose and effective dose of 18F-labelled radiotracers present with the strongest statistical correlations with body weight. For 18F-Amino acids, 18F-Brain receptor substances, 18F-FDG, 18F-L-DOPA and 18F-FBPA, the mean...... absolute effective dose differences between phantoms of different habitus and fixed reference models are 11.4%, 11.3%, 10.8%, 13.3% and 11.4%, respectively. Total body weight, standing height and sitting height have considerable effects on human internal dosimetry. Radiation dose calculations...

  16. A quantitative comparison of noise reduction across five commercial (hybrid and model-based) iterative reconstruction techniques: an anthropomorphic phantom study.

    Science.gov (United States)

    Patino, Manuel; Fuentes, Jorge M; Hayano, Koichi; Kambadakone, Avinash R; Uyeda, Jennifer W; Sahani, Dushyant V

    2015-02-01

    OBJECTIVE. The objective of our study was to compare the performance of three hybrid iterative reconstruction techniques (IRTs) (ASiR, iDose4, SAFIRE) and their respective strengths for image noise reduction on low-dose CT examinations using filtered back projection (FBP) as the standard reference. Also, we compared the performance of these three hybrid IRTs with two model-based IRTs (Veo and IMR) for image noise reduction on low-dose examinations. MATERIALS AND METHODS. An anthropomorphic abdomen phantom was scanned at 100 and 120 kVp and different tube current-exposure time products (25-100 mAs) on three CT systems (for ASiR and Veo, Discovery CT750 HD; for iDose4 and IMR, Brilliance iCT; and for SAFIRE, Somatom Definition Flash). Images were reconstructed using FBP and using IRTs at various strengths. Nine noise measurements (mean ROI size, 423 mm(2)) on extracolonic fat for the different strengths of IRTs were recorded and compared with FBP using ANOVA. Radiation dose, which was measured as the volume CT dose index and dose-length product, was also compared. RESULTS. There were no significant differences in radiation dose and image noise among the scanners when FBP was used (p > 0.05). Gradual image noise reduction was observed with each increasing increment of hybrid IRT strength, with a maximum noise suppression of approximately 50% (48.2-53.9%). Similar noise reduction was achieved on the scanners by applying specific hybrid IRT strengths. Maximum noise reduction was higher on model-based IRTs (68.3-81.1%) than hybrid IRTs (48.2-53.9%) (p < 0.05). CONCLUSION. When constant scanning parameters are used, radiation dose and image noise on FBP are similar for CT scanners made by different manufacturers. Significant image noise reduction is achieved on low-dose CT examinations rendered with IRTs. The image noise on various scanners can be matched by applying specific hybrid IRT strengths. Model-based IRTs attain substantially higher noise reduction than hybrid

  17. 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)

  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. Reminders of Social Connection Can Attenuate Anthropomorphism.

    Science.gov (United States)

    Bartz, Jennifer A; Tchalova, Kristina; Fenerci, Can

    2016-12-01

    It is a fundamental human need to secure and sustain a sense of social belonging. Previous research has shown that individuals who are lonely are more likely than people who are not lonely to attribute humanlike traits (e.g., free will) to nonhuman agents (e.g., an alarm clock that makes people get up by moving away from the sleeper), presumably in an attempt to fulfill unmet needs for belongingness. We directly replicated the association between loneliness and anthropomorphism in a larger sample ( N = 178); furthermore, we showed that reminding people of a close, supportive relationship reduces their tendency to anthropomorphize. This finding provides support for the idea that the need for belonging has causal effects on anthropomorphism. Last, we showed that attachment anxiety-characterized by intense desire for and preoccupation with closeness, fear of abandonment, and hypervigilance to social cues-was a stronger predictor of anthropomorphism than loneliness was. This finding helps clarify the mechanisms underlying anthropomorphism and supports the idea that anthropomorphism is a motivated process reflecting the active search for potential sources of connection.

  20. Construction of cardiac anthropomorphic phantom for simulation of radiological exams

    International Nuclear Information System (INIS)

    Bandeira, C.K.; Vieira Neto, H.; Vieira, M.P.M.M.

    2017-01-01

    Phantoms are simulating objects of structures of the human body and can be applied in the quality control and calibration of radiological equipment. The aim of the work is the development of a cardiac anthropomorphic phantom to assist in the elaboration of protocols of dynamic studies that demonstrate the blood circulation inside the cardiac chambers. For the construction of the phantom was used latex, applied in layers on an anatomical model of heart, having been constructed the cardiac chambers and atrioventricular valves. Cardiac chambers were connected to the cannulas for fluid injection and simulation of the circulatory system. The constructed phantom presents anthropomorphic characteristics and allows the circulation of the fluid without reflux, but the thickness of the catheters used does not yet allow flows of greater order of magnitude. This phantom has the potential to be used in the dynamic simulation of cardiac exams, contributing to the elaboration and adequacy of computed tomography protocols

  1. Improvements in seismic event locations in a deep western U.S. coal mine using tomographic velocity models and an evolutionary search algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Adam Lurka; Peter Swanson [Central Mining Institute, Katowice (Poland)

    2009-09-15

    Methods of improving seismic event locations were investigated as part of a research study aimed at reducing ground control safety hazards. Seismic event waveforms collected with a 23-station three-dimensional sensor array during longwall coal mining provide the data set used in the analyses. A spatially variable seismic velocity model is constructed using seismic event sources in a passive tomographic method. The resulting three-dimensional velocity model is used to relocate seismic event positions. An evolutionary optimization algorithm is implemented and used in both the velocity model development and in seeking improved event location solutions. Results obtained using the different velocity models are compared. The combination of the tomographic velocity model development and evolutionary search algorithm provides improvement to the event locations. 13 refs., 5 figs., 4 tabs.

  2. Frequency-domain optical tomographic image reconstruction algorithm with the simplified spherical harmonics (SP3) light propagation model.

    Science.gov (United States)

    Kim, Hyun Keol; Montejo, Ludguier D; Jia, Jingfei; Hielscher, Andreas H

    2017-06-01

    We introduce here the finite volume formulation of the frequency-domain simplified spherical harmonics model with n -th order absorption coefficients (FD-SP N ) that approximates the frequency-domain equation of radiative transfer (FD-ERT). We then present the FD-SP N based reconstruction algorithm that recovers absorption and scattering coefficients in biological tissue. The FD-SP N model with 3 rd order absorption coefficient (i.e., FD-SP 3 ) is used as a forward model to solve the inverse problem. The FD-SP 3 is discretized with a node-centered finite volume scheme and solved with a restarted generalized minimum residual (GMRES) algorithm. The absorption and scattering coefficients are retrieved using a limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. Finally, the forward and inverse algorithms are evaluated using numerical phantoms with optical properties and size that mimic small-volume tissue such as finger joints and small animals. The forward results show that the FD-SP 3 model approximates the FD-ERT (S 12 ) solution within relatively high accuracy; the average error in the phase (<3.7%) and the amplitude (<7.1%) of the partial current at the boundary are reported. From the inverse results we find that the absorption and scattering coefficient maps are more accurately reconstructed with the SP 3 model than those with the SP 1 model. Therefore, this work shows that the FD-SP 3 is an efficient model for optical tomographic imaging of small-volume media with non-diffuse properties both in terms of computational time and accuracy as it requires significantly lower CPU time than the FD-ERT (S 12 ) and also it is more accurate than the FD-SP 1 .

  3. Radiation dose evaluation of dental cone beam computed tomography using an anthropomorphic adult head phantom

    Science.gov (United States)

    Wu, Jay; Shih, Cheng-Ting; Ho, Chang-hung; Liu, Yan-Lin; Chang, Yuan-Jen; Min Chao, Max; Hsu, Jui-Ting

    2014-11-01

    Dental cone beam computed tomography (CBCT) provides high-resolution tomographic images and has been gradually used in clinical practice. Thus, it is important to examine the amount of radiation dose resulting from dental CBCT examinations. In this study, we developed an in-house anthropomorphic adult head phantom to evaluate the level of effective dose. The anthropomorphic phantom was made of acrylic and filled with plaster to replace the bony tissue. The contour of the head was extracted from a set of adult computed tomography (CT) images. Different combinations of the scanning parameters of CBCT were applied. Thermoluminescent dosimeters (TLDs) were used to measure the absorbed doses at 19 locations in the head and neck regions. The effective doses measured using the proposed phantom at 65, 75, and 85 kVp in the D-mode were 72.23, 100.31, and 134.29 μSv, respectively. In the I-mode, the effective doses were 108.24, 190.99, and 246.48 μSv, respectively. The maximum percent error between the doses measured by the proposed phantom and the Rando phantom was l4.90%. Therefore, the proposed anthropomorphic adult head phantom is applicable for assessing the radiation dose resulting from clinical dental CBCT.

  4. Software development for modeling positrons emission tomograph scanners; Desenvolvimento de um software para modelagem de tomografos por emissao de positrons

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Igor Fagner

    2013-08-01

    The Geant4 Application for Tomographic Emission (GATE) is an international platform recognized and used to develop Computational Model Exposure (CME) in the context of Nuclear Medicine, although currently there are dedicated modules for applications in Radiotherapy and Computed Tomography (CT). GATE uses Monte Carlo (MC) methods, and has a scripting language of its own. The writing of scripts for simulation of a PET scanner in GATE involves a number of interrelated steps, and the accuracy of the simulation is dependent on the correct setup of the geometries involved, since the physical processes depend on them, as well as the modeling of electronic detectors in module Digitizer, for example. The manual implementation of this setup can be a source of errors, especially for users without experience in the field of simulations or without any previous knowledge of a programming language, and also due to the the fact that the modeling process in GATE still remains bounded to LINUX / UNIX based systems, an environment only familiar to a few. This becomes an obstacle for beginners and prevents the use of GATE by a larger number of users interested in optimizing their experiments and/or clinical protocols through a more accessible, fast and friendly application. The objective of this work is therefore to develop a user-friendly software for the modeling of Positron Emission Tomography called GUIGATE (Graphical User Interface for GATE), with specific modules dedicated to quality control in PET scanners. The results exhibit the features available in this first version of GUIGATE, present in a set of windows that allow users to create their input files, perform and display in real time the model and analyze its output file in a single environment, allowing so intuitively access the entire architecture of the GATE simulation and to CERN's data analyzer, the ROOT. (author)

  5. Complex structure of the lithospheric slab beneath the Banda arc, eastern Indonesia depicted by a seismic tomographic model

    Directory of Open Access Journals (Sweden)

    Sri Widiyantoro

    2011-10-01

    Full Text Available Seismic tomography with a non-linear approach has been successfully applied to image the P-wave velocity structure beneath the Banda arc in detail. Nearly one million compressional phases including the surfacereflected depth phases pP and pwP from events within the Indonesian region have been used. The depth phases have been incorporated in order to improve the sampling of the uppermantle structure, particularly below the Banda Sea in the back-arc regions. For the model parameterization, we have combined a highresolution regional inversion with a low-resolution global inversion to allow detailed images of slab structures within the study region and to minimize the mapping of distant aspherical mantle structure into the volume under study. In this paper, we focus our discussion on the upper mantle and transition zone structure beneath the curved Banda arc. The tomographic images confirm previous observations of the twisting of the slab in the upper mantle, forming a spoon-shaped structure beneath the Banda arc. A slab lying flat on the 660 km discontinuity beneath the Banda Sea is also well imaged. Further interpretations of the resulting tomograms and seismicity data support the scenario of the Banda arc subduction rollback.

  6. On Seeing Human: A Three-Factor Theory of Anthropomorphism

    Science.gov (United States)

    Epley, Nicholas; Waytz, Adam; Cacioppo, John T.

    2007-01-01

    Anthropomorphism describes the tendency to imbue the real or imagined behavior of nonhuman agents with humanlike characteristics, motivations, intentions, or emotions. Although surprisingly common, anthropomorphism is not invariant. This article describes a theory to explain when people are likely to anthropomorphize and when they are not, focused…

  7. Generating human-like movements on an anthropomorphic robot using an interior point method

    Science.gov (United States)

    Costa e Silva, E.; Araújo, J. P.; Machado, D.; Costa, M. F.; Erlhagen, W.; Bicho, E.

    2013-10-01

    In previous work we have presented a model for generating human-like arm and hand movements on an anthropomorphic robot involved in human-robot collaboration tasks. This model was inspired by the Posture-Based Motion-Planning Model of human movements. Numerical results and simulations for reach-to-grasp movements with two different grip types have been presented previously. In this paper we extend our model in order to address the generation of more complex movement sequences which are challenged by scenarios cluttered with obstacles. The numerical results were obtained using the IPOPT solver, which was integrated in our MATLAB simulator of an anthropomorphic robot.

  8. Multi-scale mantle structure underneath the Americas from a new tomographic model of seismic shear velocity

    Science.gov (United States)

    Porritt, R. W.; Becker, T. W.; Auer, L.; Boschi, L.

    2017-12-01

    We present a whole-mantle, variable resolution, shear-wave tomography model based on newly available and existing seismological datasets including regional body-wave delay times and multi-mode Rayleigh and Love wave phase delays. Our body wave dataset includes 160,000 S wave delays used in the DNA13 regional tomographic model focused on the western and central US, 86,000 S and SKS delays measured on stations in western South America (Porritt et al., in prep), and 3,900,000 S+ phases measured by correlation between data observed at stations in the IRIS global networks (IU, II) and stations in the continuous US, against synthetic data generated with IRIS Syngine. The surface wave dataset includes fundamental mode and overtone Rayleigh wave data from Schaeffer and Levedev (2014), ambient noise derived Rayleigh wave and Love wave measurements from Ekstrom (2013), newly computed fundamental mode ambient noise Rayleigh wave phase delays for the continuous US up to July 2017, and other, previously published, measurements. These datasets, along with a data-adaptive parameterization utilized for the SAVANI model (Auer et al., 2014), should allow significantly finer-scale imaging than previous global models, rivaling that of regional-scale approaches, under the USArray footprint in the continuous US, while seamlessly integrating into a global model. We parameterize the model for both vertically (vSV) and horizontally (vSH) polarized shear velocities by accounting for the different sensitivities of the various phases and wave types. The resulting, radially anisotropic model should allow for a range of new geodynamic analysis, including estimates of mantle flow induced topography or seismic anisotropy, without generating artifacts due to edge effects, or requiring assumptions about the structure of the region outside the well resolved model space. Our model shows a number of features, including indications of the effects of edge-driven convection in the Cordillera and along

  9. 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

  10. Subduction to the lower mantle – a comparison between geodynamic and tomographic models

    Directory of Open Access Journals (Sweden)

    T. W. Becker

    2012-11-01

    Full Text Available It is generally believed that subduction of lithospheric slabs is a major contribution to thermal heterogeneity in Earth's entire mantle and provides a main driving force for mantle flow. Mantle structure can, on the one hand, be inferred from plate tectonic models of subduction history and geodynamic models of mantle flow. On the other hand, seismic tomography models provide important information on mantle heterogeneity. Yet, the two kinds of models are only similar on the largest (1000 s of km scales and are quite different in their detailed structure. Here, we provide a quantitative assessment how good a fit can be currently achieved with a simple viscous flow geodynamic model. The discrepancy between geodynamic and tomography models can indicate where further model refinement could possibly yield an improved fit. Our geodynamical model is based on 300 Myr of subduction history inferred from a global plate reconstruction. Density anomalies are inserted into the upper mantle beneath subduction zones, and flow and advection of these anomalies is calculated with a spherical harmonic code for a radial viscosity structure constrained by mineral physics and surface observations. Model viscosities in the upper mantle beneath the lithosphere are ~1020 Pas, and viscosity increases to ~1023 Pas in the lower mantle above D". Comparison with tomography models is assessed in terms of correlation, both overall and as a function of depth and spherical harmonic degree. We find that, compared to previous geodynamic and tomography models, correlation is improved, presumably because of advances in both plate reconstructions and mantle flow computations. However, high correlation is still limited to lowest spherical harmonic degrees. An important ingredient to achieve high correlation – in particular at spherical harmonic degree two – is a basal chemical layer. Subduction shapes this layer into two rather stable hot but chemically dense "piles

  11. Kinetic modeling of receptor-ligand binding applied to positron emission tomographic studies with neuroleptic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Logan, J; Wolf, A P; Shiue, C Y; Fowler, J S

    1987-01-01

    Positron emission tomography (PET) with labeled neuroleptics has made possible the study of neurotransmitter-receptor systems in vivo. In this study we investigate the kinetics of the 3,4-dihydroxyphenylethylamine (dopamine) receptor-ligand binding using PET data from a series of experiments in the baboon with the /sup 18/F-labeled drugs spiperone, haloperidol, and benperidol. Models used to describe these systems are based on first-order kinetics which applies at high specific activity (low receptor occupancy). The parameters governing the uptake and loss of drug from the brain were found by fitting PET data from regions with little or no receptor concentration (cerebellum) and from experiments in which specific binding was blocked by pretreatment with the drug (+)-butaclamol. Receptor constants were determined by fitting data from receptor-containing structures. Correcting the arterial plasma activities (the model driving function) for the presence of drug metabolites was found to be important in the modeling of these systems.

  12. A Convex Reconstruction Model for X-ray Tomographic Imaging with Uncertain Flat-fields

    DEFF Research Database (Denmark)

    Aggrawal, Hari Om; Andersen, Martin Skovgaard; Rose, Sean

    2018-01-01

    has a negligible effect on the reconstruction quality. However, in time- or dose-limited applications such as dynamic CT, this uncertainty may cause severe and systematic artifacts known as ring artifacts. By carefully modeling the measurement process and by taking uncertainties into account, we...

  13. Procedures of hepatic scintigraphy and improvement of professionals by using anthropomorphic simulator object of liver in nuclear medicine

    International Nuclear Information System (INIS)

    Ferreira, Fernanda C.L.; Cunha, Cledison J.; Dullius, Marcos A.; Souza, Divanizia N.

    2011-01-01

    This paper evaluates hepatic scintigraphy procedures and the possibility of professional improvement in nuclear medicine by using three-dimension anthropomorphic simulators representative of adult human liver. For the conformation of anthropomorphic simulator, it was used gypsum and acrylic. Three simulator objects representing cirrhosis livers. The simulator were filled with 99m Tc diluted in water for the obtention of scintigraphic images. Tomographic images were analysed posterior and anterior of simulator representing an organ with more cirrhosis grade. It was observed that the simulators make possible the acquisition of images similar to the real images of liver with hepatic cirrhosis. The simulations of hemangiomas can contribute for continuous education of nuclear medicine professionals, as far the question of image formation is concerned, make possible the parameter study as, for example, the , matrix size energy window, zoom and counting statistic

  14. Synthesized interstitial lung texture for use in anthropomorphic computational phantoms

    Science.gov (United States)

    Becchetti, Marc F.; Solomon, Justin B.; Segars, W. Paul; Samei, Ehsan

    2016-04-01

    A realistic model of the anatomical texture from the pulmonary interstitium was developed with the goal of extending the capability of anthropomorphic computational phantoms (e.g., XCAT, Duke University), allowing for more accurate image quality assessment. Contrast-enhanced, high dose, thorax images for a healthy patient from a clinical CT system (Discovery CT750HD, GE healthcare) with thin (0.625 mm) slices and filtered back- projection (FBP) were used to inform the model. The interstitium which gives rise to the texture was defined using 24 volumes of interest (VOIs). These VOIs were selected manually to avoid vasculature, bronchi, and bronchioles. A small scale Hessian-based line filter was applied to minimize the amount of partial-volumed supernumerary vessels and bronchioles within the VOIs. The texture in the VOIs was characterized using 8 Haralick and 13 gray-level run length features. A clustered lumpy background (CLB) model with added noise and blurring to match CT system was optimized to resemble the texture in the VOIs using a genetic algorithm with the Mahalanobis distance as a similarity metric between the texture features. The most similar CLB model was then used to generate the interstitial texture to fill the lung. The optimization improved the similarity by 45%. This will substantially enhance the capabilities of anthropomorphic computational phantoms, allowing for more realistic CT simulations.

  15. MicroCT-Based Skeletal Models for Use in Tomographic Voxel Phantoms for Radiological Protection

    International Nuclear Information System (INIS)

    Bolch, Wesley

    2010-01-01

    The University of Florida (UF) proposes to develop two high-resolution image-based skeletal dosimetry models for direct use by ICRP Committee 2's Task Group on Dose Calculation in their forthcoming Reference Voxel Male (RVM) and Reference Voxel Female (RVF) whole-body dosimetry phantoms. These two phantoms are CT-based, and thus do not have the image resolution to delineate and perform radiation transport modeling of the individual marrow cavities and bone trabeculae throughout their skeletal structures. Furthermore, new and innovative 3D microimaging techniques will now be required for the skeletal tissues following Committee 2's revision of the target tissues of relevance for radiogenic bone cancer induction. This target tissue had been defined in ICRP Publication 30 as a 10-(micro)m cell layer on all bone surfaces of trabecular and cortical bone. The revised target tissue is now a 50-(micro)m layer within the marrow cavities of trabecular bone only and is exclusive of the marrow adipocytes. Clearly, this new definition requires the use of 3D microimages of the trabecular architecture not available from past 2D optical studies of the adult skeleton. With our recent acquisition of two relatively young cadavers (males of age 18-years and 40-years), we will develop a series of reference skeletal models that can be directly applied to (1) the new ICRP reference voxel man and female phantoms developed for the ICRP, and (2) pediatric phantoms developed to target the ICRP reference children. Dosimetry data to be developed will include absorbed fractions for internal beta and alpha-particle sources, as well as photon and neutron fluence-to-dose response functions for direct use in external dosimetry studies of the ICRP reference workers and members of the general public

  16. MicroCT-Based Skeletal Models for Use in Tomographic Voxel Phantoms for Radiological Protection

    Energy Technology Data Exchange (ETDEWEB)

    Bolch, Wesley [Univ. of Florida, Gainesville, FL (United States)

    2010-03-30

    The University of Florida (UF) proposes to develop two high-resolution image-based skeletal dosimetry models for direct use by ICRP Committee 2’s Task Group on Dose Calculation in their forthcoming Reference Voxel Male (RVM) and Reference Voxel Female (RVF) whole-body dosimetry phantoms. These two phantoms are CT-based, and thus do not have the image resolution to delineate and perform radiation transport modeling of the individual marrow cavities and bone trabeculae throughout their skeletal structures. Furthermore, new and innovative 3D microimaging techniques will now be required for the skeletal tissues following Committee 2’s revision of the target tissues of relevance for radiogenic bone cancer induction. This target tissue had been defined in ICRP Publication 30 as a 10-μm cell layer on all bone surfaces of trabecular and cortical bone. The revised target tissue is now a 50-μm layer within the marrow cavities of trabecular bone only and is exclusive of the marrow adipocytes. Clearly, this new definition requires the use of 3D microimages of the trabecular architecture not available from past 2D optical studies of the adult skeleton. With our recent acquisition of two relatively young cadavers (males of age 18-years and 40-years), we will develop a series of reference skeletal models that can be directly applied to (1) the new ICRP reference voxel man and female phantoms developed for the ICRP, and (2) pediatric phantoms developed to target the ICRP reference children. Dosimetry data to be developed will include absorbed fractions for internal beta and alpha-particle sources, as well as photon and neutron fluence-to-dose response functions for direct use in external dosimetry studies of the ICRP reference workers and members of the general public

  17. Development of a physical 3D anthropomorphic breast phantom

    Energy Technology Data Exchange (ETDEWEB)

    Carton, Ann-Katherine; Bakic, Predrag; Ullberg, Christer; Derand, Helen; Maidment, Andrew D. A. [Department of Radiology, University of Pennsylvania, 1 Silverstein Building, 3400 Spruce Street, Philadelphia, Pennsylvania 19104-4206 (United States); XCounter AB, Svaerdvaegen 11, SE-182 33 Danderyd (Sweden); Department of Radiology, University of Pennsylvania, 1 Silverstein Building, 3400 Spruce Street, Philadelphia, Pennsylvania 19104-4206 (United States)

    2011-02-15

    Purpose: Develop a technique to fabricate a 3D anthropomorphic breast phantom with known ground truth for image quality assessment of 2D and 3D breast x-ray imaging systems. Methods: The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying composition, size, and shape. The physical phantom is produced in two steps. First, the portion of the voxel phantom consisting of the glandular tissue, skin, and Cooper's ligaments is separated into sections. These sections are then fabricated by high-resolution rapid prototyping using a single material with 50% glandular equivalence. The remaining adipose compartments are then filled using an epoxy-based resin (EBR) with 100% adipose equivalence. The phantom sections are stacked to form the physical anthropomorphic phantom. Results: The authors fabricated a prototype phantom corresponding to a 450 ml breast with 45% dense tissue, deformed to a 5 cm compressed thickness. Both the rapid prototype (RP) and EBR phantom materials are radiographically uniform. The coefficient of variation (CoV) of the relative attenuation between RP and EBR phantom samples was <1% and the CoV of the signal intensity within RP and EBR phantom samples was <1.5% on average. Digital mammography and reconstructed digital breast tomosynthesis images of the authors' phantom were reviewed by two radiologists; they reported that the images are similar in appearance to clinical images, noting there are still artifacts from air bubbles in the EBR. Conclusions: The authors have developed a technique to produce 3D anthropomorphic breast phantoms with known ground truth, yielding highly realistic x-ray images. Such phantoms may serve both qualitative and quantitative performance assessments for 2D and 3D breast x-ray imaging systems.

  18. 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)

  19. Relocating San Miguel Volcanic Seismic Events for Receiver Functions and Tomographic Models

    Science.gov (United States)

    Patlan, E.; Velasco, A. A.; Konter, J.

    2009-12-01

    The San Miguel volcano lies near the city of San Miguel, El Salvador (13.43N and -88.26W). San Miguel volcano, an active stratovolcano, presents a significant natural hazard for the city of San Miguel. Furthermore, the internal state and activity of volcanoes remains an important component to understanding volcanic hazard. The main technology for addressing volcanic hazards and processes is through the analysis of data collected from the deployment of seismic sensors that record ground motion. Six UTEP seismic stations were deployed around San Miguel volcano from 2007-2008 to define the magma chamber and assess the seismic and volcanic hazard. We utilize these data to develop images of the earth structure beneath the volcano, studying the volcanic processes by identifying different sources, and investigating the role of earthquakes and faults in controlling the volcanic processes. We will calculate receiver functions to determine the thickness of San Miguel volcano internal structure, within the Caribbean plate. Crustal thicknesses will be modeled using calculated receiver functions from both theoretical and hand-picked P-wave arrivals. We will use this information derived from receiver functions, along with P-wave delay times, to map the location of the magma chamber.

  20. Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies.

    Science.gov (United States)

    Häggström, Ida; Beattie, Bradley J; Schmidtlein, C Ross

    2016-06-01

    To develop and evaluate a fast and simple tool called dpetstep (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. The tool was developed in matlab using both new and previously reported modules of petstep (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). dpetstep was 8000 times faster than MC. Dynamic images from dpetstep had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dpetstep and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dpetstep images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dpetstep to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for studies investigating these phenomena. dpetstep can be downloaded free of cost from https://github.com/CRossSchmidtlein/dPETSTEP.

  1. Revisiting the Effect of Anthropomorphizing a Social Cause Campaign.

    Directory of Open Access Journals (Sweden)

    Lisa A Williams

    Full Text Available Recent research suggests that anthropomorphism can be harnessed as a tool to boost intentions to comply with social cause campaigns. Drawing on the human tendency to extend moral concern to entities portrayed as humanlike, it has been argued that adding personified features to a social campaign elevates anticipated guilt at failing to comply, and this subsequently boosts intentions to comply with that campaign. The present research aimed to extend extant research by disentangling the effects of emotional and non-emotional anthropomorphism, and differentiating amongst other emotional mechanisms of the anthropomorphism-compliance effect (namely, anticipated pride and anticipated regret. Experiment 1 (N = 294 compared the effectiveness of positive, negative, and emotionally-neutral anthropomorphized campaign posters for boosting campaign compliance intentions against non-anthropomorphized posters. We also measured potential mechanisms including anticipated guilt, regret, and pride. Results failed to support the anthropomorphism-compliance effect, and no changes in anticipated emotion according to anthropomorphism emerged. Experiments 2 (N = 150 and 3 (N = 196 represented further tests of the anthropomorphism-compliance effect. Despite high statistical power and efforts to closely replicate the conditions under which the anthropomorphism-compliance effect had been previously observed, no differences in compliance intention or anticipated emotion according to anthropomorphism emerged. A meta-analysis of the effects of anthropomorphism on compliance and anticipated emotion across the three experiments revealed effect size estimates that did not differ significantly from zero. The results of these three experiments suggest that the anthropomorphism-compliance effect is fragile and perhaps subject to contextual and idiographic influences. Thus, this research provides important insight and impetus for future research on the applied and theoretical

  2. Revisiting the Effect of Anthropomorphizing a Social Cause Campaign.

    Science.gov (United States)

    Williams, Lisa A; Masser, Barbara; Sun, Jessie

    2015-01-01

    Recent research suggests that anthropomorphism can be harnessed as a tool to boost intentions to comply with social cause campaigns. Drawing on the human tendency to extend moral concern to entities portrayed as humanlike, it has been argued that adding personified features to a social campaign elevates anticipated guilt at failing to comply, and this subsequently boosts intentions to comply with that campaign. The present research aimed to extend extant research by disentangling the effects of emotional and non-emotional anthropomorphism, and differentiating amongst other emotional mechanisms of the anthropomorphism-compliance effect (namely, anticipated pride and anticipated regret). Experiment 1 (N = 294) compared the effectiveness of positive, negative, and emotionally-neutral anthropomorphized campaign posters for boosting campaign compliance intentions against non-anthropomorphized posters. We also measured potential mechanisms including anticipated guilt, regret, and pride. Results failed to support the anthropomorphism-compliance effect, and no changes in anticipated emotion according to anthropomorphism emerged. Experiments 2 (N = 150) and 3 (N = 196) represented further tests of the anthropomorphism-compliance effect. Despite high statistical power and efforts to closely replicate the conditions under which the anthropomorphism-compliance effect had been previously observed, no differences in compliance intention or anticipated emotion according to anthropomorphism emerged. A meta-analysis of the effects of anthropomorphism on compliance and anticipated emotion across the three experiments revealed effect size estimates that did not differ significantly from zero. The results of these three experiments suggest that the anthropomorphism-compliance effect is fragile and perhaps subject to contextual and idiographic influences. Thus, this research provides important insight and impetus for future research on the applied and theoretical utility of

  3. Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies

    Energy Technology Data Exchange (ETDEWEB)

    Häggström, Ida, E-mail: haeggsti@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and Department of Radiation Sciences, Umeå University, Umeå 90187 (Sweden); Beattie, Bradley J.; Schmidtlein, C. Ross [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States)

    2016-06-15

    Purpose: To develop and evaluate a fast and simple tool called dPETSTEP (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. Methods: The tool was developed in MATLAB using both new and previously reported modules of PETSTEP (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). Results: dPETSTEP was 8000 times faster than MC. Dynamic images from dPETSTEP had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dPETSTEP and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dPETSTEP images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p < 0.01). Compared to GAUSS, dPETSTEP images and noise properties agreed better with MC. Conclusions: The authors have developed a fast and easy one-stop solution for simulations of dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dPETSTEP to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for

  4. Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies

    International Nuclear Information System (INIS)

    Häggström, Ida; Beattie, Bradley J.; Schmidtlein, C. Ross

    2016-01-01

    Purpose: To develop and evaluate a fast and simple tool called dPETSTEP (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. Methods: The tool was developed in MATLAB using both new and previously reported modules of PETSTEP (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). Results: dPETSTEP was 8000 times faster than MC. Dynamic images from dPETSTEP had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dPETSTEP and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dPETSTEP images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p < 0.01). Compared to GAUSS, dPETSTEP images and noise properties agreed better with MC. Conclusions: The authors have developed a fast and easy one-stop solution for simulations of dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dPETSTEP to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for

  5. 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.)

  6. 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.)

  7. 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.)

  8. 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.)

  9. Rotating and translating anthropomorphic head voxel models to establish an horizontal Frankfort plane for dental CBCT Monte Carlo simulations: a dose comparison study

    Science.gov (United States)

    Stratis, A.; Zhang, G.; Jacobs, R.; Bogaerts, R.; Bosmans, H.

    2016-12-01

    In order to carry out Monte Carlo (MC) dosimetry studies, voxel phantoms, modeling human anatomy, and organ-based segmentation of CT image data sets are applied to simulation frameworks. The resulting voxel phantoms preserve patient CT acquisition geometry; in the case of head voxel models built upon head CT images, the head support with which CT scanners are equipped introduces an inclination to the head, and hence to the head voxel model. In dental cone beam CT (CBCT) imaging, patients are always positioned in such a way that the Frankfort line is horizontal, implying that there is no head inclination. The orientation of the head is important, as it influences the distance of critical radiosensitive organs like the thyroid and the esophagus from the x-ray tube. This work aims to propose a procedure to adjust head voxel phantom orientation, and to investigate the impact of head inclination on organ doses in dental CBCT MC dosimetry studies. The female adult ICRP, and three in-house-built paediatric voxel phantoms were in this study. An EGSnrc MC framework was employed to simulate two commonly used protocols; a Morita Accuitomo 170 dental CBCT scanner (FOVs: 60  ×  60 mm2 and 80  ×  80 mm2, standard resolution), and a 3D Teeth protocol (FOV: 100  ×  90 mm2) in a Planmeca Promax 3D MAX scanner. Result analysis revealed large absorbed organ dose differences in radiosensitive organs between the original and the geometrically corrected voxel models of this study, ranging from  -45.6% to 39.3%. Therefore, accurate dental CBCT MC dose calculations require geometrical adjustments to be applied to head voxel models.

  10. Dynamic 99mTc-MAG3 renography: images for quality control obtained by combining pharmacokinetic modelling, an anthropomorphic computer phantom and Monte Carlo simulated scintillation camera imaging

    Science.gov (United States)

    Brolin, Gustav; Sjögreen Gleisner, Katarina; Ljungberg, Michael

    2013-05-01

    In dynamic renal scintigraphy, the main interest is the radiopharmaceutical redistribution as a function of time. Quality control (QC) of renal procedures often relies on phantom experiments to compare image-based results with the measurement setup. A phantom with a realistic anatomy and time-varying activity distribution is therefore desirable. This work describes a pharmacokinetic (PK) compartment model for 99mTc-MAG3, used for defining a dynamic whole-body activity distribution within a digital phantom (XCAT) for accurate Monte Carlo (MC)-based images for QC. Each phantom structure is assigned a time-activity curve provided by the PK model, employing parameter values consistent with MAG3 pharmacokinetics. This approach ensures that the total amount of tracer in the phantom is preserved between time points, and it allows for modifications of the pharmacokinetics in a controlled fashion. By adjusting parameter values in the PK model, different clinically realistic scenarios can be mimicked, regarding, e.g., the relative renal uptake and renal transit time. Using the MC code SIMIND, a complete set of renography images including effects of photon attenuation, scattering, limited spatial resolution and noise, are simulated. The obtained image data can be used to evaluate quantitative techniques and computer software in clinical renography.

  11. Anthropomorphic reasoning about neuromorphic AGI safety

    Science.gov (United States)

    Jilk, David J.; Herd, Seth J.; Read, Stephen J.; O'Reilly, Randall C.

    2017-11-01

    One candidate approach to creating artificial general intelligence (AGI) is to imitate the essential computations of human cognition. This process is sometimes called 'reverse-engineering the brain' and the end product called 'neuromorphic.' We argue that, unlike with other approaches to AGI, anthropomorphic reasoning about behaviour and safety concerns is appropriate and crucial in a neuromorphic context. Using such reasoning, we offer some initial ideas to make neuromorphic AGI safer. In particular, we explore how basic drives that promote social interaction may be essential to the development of cognitive capabilities as well as serving as a focal point for human-friendly outcomes.

  12. Status and Trends of the Anthropomorphic Robotics

    Directory of Open Access Journals (Sweden)

    S. P. Hurs

    2016-01-01

    Full Text Available The paper considers a number of current developments in the field of anthropomorphic robotics, namely robotic exoskeletons, android platform with copying control systems, android platform with autonomous control systems, avatars, and androids. Highlights the key subsystems of the robotic platform such as sensitization tools, tools of self-diagnostics, security and prioritization, a power subsystem, and computer system. Identifies the most important subsystem of a “future soldier” to represent an equipage as a multifunctional active exoskeleton, completed with the necessary equipment.The paper shows the main problems the developers of anthropomorphic robotics face. For example, many degrees of the human body freedom curb a creation of the actuating mechanisms of robots, which fit the human anatomy as much as possible. For the human sizes the specific characteristics of traditional types of actuators, such as electromechanical, electro-hydraulic and electro-pneumatic are worse than those of the human muscles. Clearly, the greatest prospects in this area are associated with artificial muscles. There is also no so far a solution for the problem of creating the feedbacks in all kinds of senses to ensure that an operator has a feeling that he is in the place of the robot. There is much tension around the issue of creating a perfect remote control system that allows the operator to obtain unambiguous signals to control the robot. There is currently no completely autonomous control system with elements of artificial intelligence. Particular attention is paid to the problems of creating power sources that can provide affordable autonomy for mobile robotic systems. The most, presently, promising power sources are mentioned.The paper considers some development aspects of the control system, which is capable to run in a copier, supervisory, combined and offline modes. Presents the most important functions of the robot sensory system. Shows some aspects

  13. 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

  14. Anthropomorphic Networks as Representatives of Global Consciousness

    Directory of Open Access Journals (Sweden)

    Sergii Yahodzinskyi

    2018-02-01

    Full Text Available There has been analyzed a phenomenon of global consciousness, and its cultural and historical, civilizational dimensions have been substantiated. There has been demonstrated that the concept of planetary consciousness, global thinking, noosphere was described for the first time in the philosophy of cosmism. However, in modern conditions ideas of representatives of the naturalistic philosophical direction of cosmism have not lost their heuristic potential. They can be reconsidered in a new fashion within the context of emerging anthropomorphic (human dimension networks. There has been proved that global consciousness is a component of the social and cultural potential of global information networks defining vectors to prospects of humanity progress in the 21st century. Relying on methodology of the structural and functional analysis, the author arrives at a conclusion about global networks obtaining the status of representatives of global consciousness. This is the area of networks where all relevant information is concentrated – from statistical data to scientific and technical information. Access to these data is limited by human abilities and is realized in the form of discrete requests with using heuristic algorithms of information procession. A suggestion is introduced considering the fact that modern society being a self-organized system seeks to gain stable condition. Anthropomorphic networks are means of decreasing social entropy, which is growing as a result of any kind of human intervention into social processes. Thus, for the first time a human is challenged by their intellect, ability to create, discover and control.

  15. 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

  16. Anthropomorphism in Decorative Pictures: Benefit or Harm for Learning?

    Science.gov (United States)

    Schneider, Sascha; Nebel, Steve; Beege, Maik; Rey, Günter Daniel

    2018-01-01

    When people attribute human characteristics to nonhuman objects they are amenable to anthropomorphism. For example, human faces or the insertion of personalized labels are found to trigger anthropomorphism. Two studies examine the effects of these features when included in decorative pictures in multimedia learning materials. In a first…

  17. 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)

  18. Is this car looking at you? How anthropomorphism predicts fusiform face area activation when seeing cars.

    Science.gov (United States)

    Kühn, Simone; Brick, Timothy R; Müller, Barbara C N; Gallinat, Jürgen

    2014-01-01

    Anthropomorphism encompasses the attribution of human characteristics to non-living objects. In particular the human tendency to see faces in cars has long been noticed, yet its neural correlates are unknown. We set out to investigate whether the fusiform face area (FFA) is associated with seeing human features in car fronts, or whether, the higher-level theory of mind network (ToM), namely temporoparietal junction (TPJ) and medial prefrontal cortex (MPFC) show a link to anthropomorphism. Twenty participants underwent fMRI scanning during a passive car-front viewing task. We extracted brain activity from FFA, TPJ and MPFC. After the fMRI session participants were asked to spontaneously list adjectives that characterize each car front. Five raters judged the degree to which each adjective can be applied as a characteristic of human beings. By means of linear mixed models we found that the implicit tendency to anthropomorphize individual car fronts predicts FFA, but not TPJ or MPFC activity. The results point to an important role of FFA in the phenomenon of ascribing human attributes to non-living objects. Interestingly, brain regions that have been associated with thinking about beliefs and mental states of others (TPJ, MPFC) do not seem to be related to anthropomorphism of car fronts.

  19. Segmentation-DrivenTomographic Reconstruction

    DEFF Research Database (Denmark)

    Kongskov, Rasmus Dalgas

    such that the segmentation subsequently can be carried out by use of a simple segmentation method, for instance just a thresholding method. We tested the advantages of going from a two-stage reconstruction method to a one stage segmentation-driven reconstruction method for the phase contrast tomography reconstruction......The tomographic reconstruction problem is concerned with creating a model of the interior of an object from some measured data, typically projections of the object. After reconstructing an object it is often desired to segment it, either automatically or manually. For computed tomography (CT...

  20. 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.)

  1. A statistically defined anthropomorphic software breast phantom

    International Nuclear Information System (INIS)

    Lau, Beverly A.; Reiser, Ingrid; Nishikawa, Robert M.; Bakic, Predrag R.

    2012-01-01

    Purpose: Digital anthropomorphic breast phantoms have emerged in the past decade because of recent advances in 3D breast x-ray imaging techniques. Computer phantoms in the literature have incorporated power-law noise to represent glandular tissue and branching structures to represent linear components such as ducts. When power-law noise is added to those phantoms in one piece, the simulated fibroglandular tissue is distributed randomly throughout the breast, resulting in dense tissue placement that may not be observed in a real breast. The authors describe a method for enhancing an existing digital anthropomorphic breast phantom by adding binarized power-law noise to a limited area of the breast. Methods: Phantoms with (0.5 mm) 3 voxel size were generated using software developed by Bakic et al. Between 0% and 40% of adipose compartments in each phantom were replaced with binarized power-law noise (β = 3.0) ranging from 0.1 to 0.6 volumetric glandular fraction. The phantoms were compressed to 7.5 cm thickness, then blurred using a 3 × 3 boxcar kernel and up-sampled to (0.1 mm) 3 voxel size using trilinear interpolation. Following interpolation, the phantoms were adjusted for volumetric glandular fraction using global thresholding. Monoenergetic phantom projections were created, including quantum noise and simulated detector blur. Texture was quantified in the simulated projections using power-spectrum analysis to estimate the power-law exponent β from 25.6 × 25.6 mm 2 regions of interest. Results: Phantoms were generated with total volumetric glandular fraction ranging from 3% to 24%. Values for β (averaged per projection view) were found to be between 2.67 and 3.73. Thus, the range of textures of the simulated breasts covers the textures observed in clinical images. Conclusions: Using these new techniques, digital anthropomorphic breast phantoms can be generated with a variety of glandular fractions and patterns. β values for this new phantom are comparable

  2. Humanizing machines: Anthropomorphization of slot machines increases gambling.

    Science.gov (United States)

    Riva, Paolo; Sacchi, Simona; Brambilla, Marco

    2015-12-01

    Do people gamble more on slot machines if they think that they are playing against humanlike minds rather than mathematical algorithms? Research has shown that people have a strong cognitive tendency to imbue humanlike mental states to nonhuman entities (i.e., anthropomorphism). The present research tested whether anthropomorphizing slot machines would increase gambling. Four studies manipulated slot machine anthropomorphization and found that exposing people to an anthropomorphized description of a slot machine increased gambling behavior and reduced gambling outcomes. Such findings emerged using tasks that focused on gambling behavior (Studies 1 to 3) as well as in experimental paradigms that included gambling outcomes (Studies 2 to 4). We found that gambling outcomes decrease because participants primed with the anthropomorphic slot machine gambled more (Study 4). Furthermore, we found that high-arousal positive emotions (e.g., feeling excited) played a role in the effect of anthropomorphism on gambling behavior (Studies 3 and 4). Our research indicates that the psychological process of gambling-machine anthropomorphism can be advantageous for the gaming industry; however, this may come at great expense for gamblers' (and their families') economic resources and psychological well-being. (c) 2015 APA, all rights reserved).

  3. 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

  4. 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)

  5. Development of thyroid anthropomorphic phantoms for use in nuclear medicine

    Science.gov (United States)

    Cerqueira, R. A. D.; Maia, A. F.

    2014-02-01

    The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers.

  6. 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

  7. Anthropomorphic Robot Design and User Interaction Associated with Motion

    Science.gov (United States)

    Ellis, Stephen R.

    2016-01-01

    Though in its original concept a robot was conceived to have some human-like shape, most robots now in use have specific industrial purposes and do not closely resemble humans. Nevertheless, robots that resemble human form in some way have continued to be introduced. They are called anthropomorphic robots. The fact that the user interface to all robots is now highly mediated means that the form of the user interface is not necessarily connected to the robots form, human or otherwise. Consequently, the unique way the design of anthropomorphic robots affects their user interaction is through their general appearance and the way they move. These robots human-like appearance acts as a kind of generalized predictor that gives its operators, and those with whom they may directly work, the expectation that they will behave to some extent like a human. This expectation is especially prominent for interactions with social robots, which are built to enhance it. Often interaction with them may be mainly cognitive because they are not necessarily kinematically intricate enough for complex physical interaction. Their body movement, for example, may be limited to simple wheeled locomotion. An anthropomorphic robot with human form, however, can be kinematically complex and designed, for example, to reproduce the details of human limb, torso, and head movement. Because of the mediated nature of robot control, there remains in general no necessary connection between the specific form of user interface and the anthropomorphic form of the robot. But their anthropomorphic kinematics and dynamics imply that the impact of their design shows up in the way the robot moves. The central finding of this report is that the control of this motion is a basic design element through which the anthropomorphic form can affect user interaction. In particular, designers of anthropomorphic robots can take advantage of the inherent human-like movement to 1) improve the users direct manual control over

  8. Seeing More Than Human: Autism and Anthropomorphic Theory of Mind

    Directory of Open Access Journals (Sweden)

    Gray Atherton

    2018-04-01

    Full Text Available Theory of mind (ToM is defined as the process of taking another’s perspective. Anthropomorphism can be seen as the extension of ToM to non-human entities. This review examines the literature concerning ToM and anthropomorphism in relation to individuals with Autism Spectrum Disorder (ASD, specifically addressing the questions of how and why those on the spectrum both show an increased interest for anthropomorphism and may even show improved ToM abilities when judging the mental states of anthropomorphic characters. This review highlights that while individuals with ASD traditionally show deficits on a wide range of ToM tests, such as recognizing facial emotions, such ToM deficits may be ameliorated if the stimuli presented is cartoon or animal-like rather than in human form. Individuals with ASD show a greater interest in anthropomorphic characters and process the features of these characters using methods typically reserved for human stimuli. Personal accounts of individuals with ASD also suggest they may identify more closely with animals than other humans. It is shown how the social motivations hypothesized to underlie the anthropomorphizing of non-human targets may lead those on the spectrum to seek social connections and therefore gain ToM experience and expertise amongst unlikely sources.

  9. Development of thyroid anthropomorphic phantoms for use in nuclear medicine

    International Nuclear Information System (INIS)

    Cerqueira, R.A.D.; Maia, A.F.

    2014-01-01

    The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers. - Highlights: ► Two thyroid phantoms were developed (OSCT and OSAP) with different types of acrylics. ► Thyroid glands were represented anthropomorphically in the both phantoms. ► Different prototypes of thyroid were built of simulate healthy or unhealthy glands. ► Images indicate that anthropomorphic phantoms correctly simulate the thyroid gland

  10. Embodied neurofeedback with an anthropomorphic robotic hand.

    Science.gov (United States)

    Braun, Niclas; Emkes, Reiner; Thorne, Jeremy D; Debener, Stefan

    2016-11-21

    Neurofeedback-guided motor imagery training (NF-MIT) has been suggested as a promising therapy for stroke-induced motor impairment. Whereas much NF-MIT research has aimed at signal processing optimization, the type of sensory feedback given to the participant has received less attention. Often the feedback signal is highly abstract and not inherently coupled to the mental act performed. In this study, we asked whether an embodied feedback signal is more efficient for neurofeedback operation than a non-embodiable feedback signal. Inspired by the rubber hand illusion, demonstrating that an artificial hand can be incorporated into one's own body scheme, we used an anthropomorphic robotic hand to visually guide the participants' motor imagery act and to deliver neurofeedback. Using two experimental manipulations, we investigated how a participant's neurofeedback performance and subjective experience were influenced by the embodiability of the robotic hand, and by the neurofeedback signal's validity. As pertains to embodiment, we found a promoting effect of robotic-hand embodiment in subjective, behavioral, electrophysiological and electrodermal measures. Regarding neurofeedback signal validity, we found some differences between real and sham neurofeedback in terms of subjective and electrodermal measures, but not in terms of behavioral and electrophysiological measures. This study motivates the further development of embodied feedback signals for NF-MIT.

  11. Embodied neurofeedback with an anthropomorphic robotic hand

    Science.gov (United States)

    Braun, Niclas; Emkes, Reiner; Thorne, Jeremy D.; Debener, Stefan

    2016-01-01

    Neurofeedback-guided motor imagery training (NF-MIT) has been suggested as a promising therapy for stroke-induced motor impairment. Whereas much NF-MIT research has aimed at signal processing optimization, the type of sensory feedback given to the participant has received less attention. Often the feedback signal is highly abstract and not inherently coupled to the mental act performed. In this study, we asked whether an embodied feedback signal is more efficient for neurofeedback operation than a non-embodiable feedback signal. Inspired by the rubber hand illusion, demonstrating that an artificial hand can be incorporated into one’s own body scheme, we used an anthropomorphic robotic hand to visually guide the participants’ motor imagery act and to deliver neurofeedback. Using two experimental manipulations, we investigated how a participant’s neurofeedback performance and subjective experience were influenced by the embodiability of the robotic hand, and by the neurofeedback signal’s validity. As pertains to embodiment, we found a promoting effect of robotic-hand embodiment in subjective, behavioral, electrophysiological and electrodermal measures. Regarding neurofeedback signal validity, we found some differences between real and sham neurofeedback in terms of subjective and electrodermal measures, but not in terms of behavioral and electrophysiological measures. This study motivates the further development of embodied feedback signals for NF-MIT. PMID:27869190

  12. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    Abele, M.

    1983-01-01

    A computerized tomographic scanning apparatus suitable for diagnosis and for improving target identification in stereotactic neurosurgery is described. It consists of a base, a source of penetrating energy, a detector which produces scanning signals and detector positioning means. A frame with top and bottom arms secures the detector and source to the top and bottom arms respectively. A drive mechanism rotates the frame about an axis along which the frame may also be moved. Finally, the detector may be moved relative to the bottom arm in a direction contrary to the rotation of the frame. (U.K.)

  13. Creating an anthropomorphic digital MR phantom—an extensible tool for comparing and evaluating quantitative imaging algorithms

    International Nuclear Information System (INIS)

    Bosca, Ryan J; Jackson, Edward F

    2016-01-01

    Assessing and mitigating the various sources of bias and variance associated with image quantification algorithms is essential to the use of such algorithms in clinical research and practice. Assessment is usually accomplished with grid-based digital reference objects (DRO) or, more recently, digital anthropomorphic phantoms based on normal human anatomy. Publicly available digital anthropomorphic phantoms can provide a basis for generating realistic model-based DROs that incorporate the heterogeneity commonly found in pathology. Using a publicly available vascular input function (VIF) and digital anthropomorphic phantom of a normal human brain, a methodology was developed to generate a DRO based on the general kinetic model (GKM) that represented realistic and heterogeneously enhancing pathology. GKM parameters were estimated from a deidentified clinical dynamic contrast-enhanced (DCE) MRI exam. This clinical imaging volume was co-registered with a discrete tissue model, and model parameters estimated from clinical images were used to synthesize a DCE-MRI exam that consisted of normal brain tissues and a heterogeneously enhancing brain tumor. An example application of spatial smoothing was used to illustrate potential applications in assessing quantitative imaging algorithms. A voxel-wise Bland–Altman analysis demonstrated negligible differences between the parameters estimated with and without spatial smoothing (using a small radius Gaussian kernel). In this work, we reported an extensible methodology for generating model-based anthropomorphic DROs containing normal and pathological tissue that can be used to assess quantitative imaging algorithms. (paper)

  14. An EGS4-ready tomographic computational model of a 14-year-old female torso for calculating organ doses from CT examinations

    International Nuclear Information System (INIS)

    Caon, M.; School of Physics and Electronic Systems Engineering, University of South Australia, The Levels Campus, Mawson Lakes, South Australia, 5095; Pattison, J.

    1999-01-01

    Fifty-four consecutive CT scans have been used to construct a tomographic computational model of a 14-year-old female torso suitable for the determination of organ doses from CT. The model, known as ADELAIDE, is in the form of an input file compatible with user codes based on XYZDOS.MOR from the readily available EGS4 Monte Carlo radiation transport code. ADELAIDE's dimensions are close to the Australian averages for her age so the model is representative of a 14-year-old girl. The realistic anatomy in the model differs considerably from that in Cristy's 15-year-old mathematical computational model by having realistically shaped organs that are appropriately located within a real external contour. Average absorbed dose to organs from simulated CT examinations of the chest and abdomen have been calculated for ADELAIDE using EGS4 within a geometry specific to the General Electric Hi-Speed Advantage CT scanner and using an x-ray spectrum calculated using data from the scanner's x-ray tube. The simulations include the scanner's beam shaping filter and patient table. It is suggested that the resulting values have fewer possible sources of uncertainty than organ doses derived from dose coefficients calculated for a MIRD style model with mathematical anatomy and a spectrum that may not match that of the scanner. The organ doses were normalized using the scanner's CTDI measured free-in-air and an EGS4 simulation of the CTDI measurement. Effective dose to the torso from 26-slice chest and 24-slice abdomen examinations (at 120 kV, 200 mAs, 7 mm slices) is 4.6±0.1mSv and 4.3±0.1mSv respectively. (author)

  15. Brain Responses Underlying Anthropomorphism, Agency, and Social Attribution in Autism Spectrum Disorder.

    Science.gov (United States)

    Ammons, Carla J; Doss, Constance F; Bala, David; Kana, Rajesh K

    2018-01-01

    Theory of Mind (ToM), the ability to attribute mental states to oneself and others, is frequently impaired in Autism Spectrum Disorder (ASD) and may result from altered activation of social brain regions. Conversely, Typically Developing (TD) individuals overextend ToM and show a strong tendency to anthropomorphize and interpret biological motion in the environment. Less is known about how the degree of anthropomorphism influences intentional attribution and engagement of the social brain in ASD. This fMRI study examines the extent of anthropomorphism, its role in social attribution, and the underlying neural responses in ASD and TD using a series of human stick figures and geometrical shapes. 14 ASD and 14 TD adults watched videos of stick figures and triangles interacting in random or socially meaningful ways while in an fMRI scanner. In addition, they completed out-of-scanner measures of ToM skill and real-world social deficits. Whole brain statistical analysis was performed for regression and within and between group comparisons of all conditions using SPM12's implementation of the general linear model. ToM network regions were activated in response to social movement and human-like characters in ASD and TD. In addition, greater ToM ability was associated with increased TPJ and MPFC activity while watching stick figures; whereas more severe social symptoms were associated with reduced right TPJ activation in response to social movement. These results suggest that degree of anthropomorphism does not differentially affect social attribution in ASD and highlights the importance of TPJ in ToM and social attribution.

  16. 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.)

  17. Emission computed tomograph

    International Nuclear Information System (INIS)

    Hirose, Y.; Kanno, I.; Koga, K.; Miura, S.; Uemura, K.

    1981-01-01

    Emission computed tomograph wherein a pluralty of detectors surround an object to be examined so as to detect x- or gamma radiation emitted by said object. In front of each of said detectors there is provided a collimator which comprises a pair of main plates and a subsidiary plate interposed therebetween. The plates are made of a material capable of blocking penetration of the radiation therethrough and so supported as to be swingable over an angle sufficient to cover the whole of said object. The plates of all the collimators are simultaneously swung to the same side and at the same angular speed thereby to change the direction of incidence of said radiation on each of said detectors

  18. 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)

  19. Social Cognition Unbound: Insights Into Anthropomorphism and Dehumanization.

    Science.gov (United States)

    Waytz, Adam; Epley, Nicholas; Cacioppo, John T

    2010-02-01

    People conceive of wrathful gods, fickle computers, and selfish genes, attributing human characteristics to a variety of supernatural, technological, and biological agents. This tendency to anthropomorphize nonhuman agents figures prominently in domains ranging from religion to marketing to computer science. Perceiving an agent to be humanlike has important implications for whether the agent is capable of social influence, accountable for its actions, and worthy of moral care and consideration. Three primary factors-elicited agent knowledge, sociality motivation, and effectance motivation-appear to account for a significant amount of variability in anthropomorphism. Identifying these factors that lead people to see nonhuman agents as humanlike also sheds light on the inverse process of dehumanization, whereby people treat human agents as animals or objects. Understanding anthropomorphism can contribute to a more expansive view of social cognition that applies social psychological theory to a wide variety of both human and nonhuman agents.

  20. 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.

  1. Anthropomorphism in Human-Robot Co-evolution.

    Science.gov (United States)

    Damiano, Luisa; Dumouchel, Paul

    2018-01-01

    Social robotics entertains a particular relationship with anthropomorphism, which it neither sees as a cognitive error, nor as a sign of immaturity. Rather it considers that this common human tendency, which is hypothesized to have evolved because it favored cooperation among early humans, can be used today to facilitate social interactions between humans and a new type of cooperative and interactive agents - social robots. This approach leads social robotics to focus research on the engineering of robots that activate anthropomorphic projections in users. The objective is to give robots "social presence" and "social behaviors" that are sufficiently credible for human users to engage in comfortable and potentially long-lasting relations with these machines. This choice of 'applied anthropomorphism' as a research methodology exposes the artifacts produced by social robotics to ethical condemnation: social robots are judged to be a "cheating" technology, as they generate in users the illusion of reciprocal social and affective relations. This article takes position in this debate, not only developing a series of arguments relevant to philosophy of mind, cognitive sciences, and robotic AI, but also asking what social robotics can teach us about anthropomorphism. On this basis, we propose a theoretical perspective that characterizes anthropomorphism as a basic mechanism of interaction, and rebuts the ethical reflections that a priori condemns "anthropomorphism-based" social robots. To address the relevant ethical issues, we promote a critical experimentally based ethical approach to social robotics, "synthetic ethics," which aims at allowing humans to use social robots for two main goals: self-knowledge and moral growth.

  2. Effective dose measurement at workplaces within an instrumented anthropomorphic phantom

    International Nuclear Information System (INIS)

    Villagrasa, C.; Darreon, J.; Martin-Burtat, N.; Clairand, I.; Colin, J.; Fontbonne, J. M.

    2011-01-01

    The Laboratory of Ionizing Radiation Dosimetry of the IRSN (France) is developing an instrumented anthropomorphic phantom in order to measure the effective dose for photon fields at workplaces. This anthropomorphic phantom will be equipped with small active detectors located inside at chosen positions. The aim of this paper is to present the development of these new detectors showing the results of the characterisation of the prototype under metrological conditions. New evaluations of the effective dose for standard and non-homogenous irradiation configurations taking into account the real constraints of the project have been done validating the feasibility and utility of the instrument. (authors)

  3. Algorithms of walking and stability for an anthropomorphic robot

    Science.gov (United States)

    Sirazetdinov, R. T.; Devaev, V. M.; Nikitina, D. V.; Fadeev, A. Y.; Kamalov, A. R.

    2017-09-01

    Autonomous movement of an anthropomorphic robot is considered as a superposition of a set of typical elements of movement - so-called patterns, each of which can be considered as an agent of some multi-agent system [ 1 ]. To control the AP-601 robot, an information and communication infrastructure has been created that represents some multi-agent system that allows the development of algorithms for individual patterns of moving and run them in the system as a set of independently executed and interacting agents. The algorithms of lateral movement of the anthropomorphic robot AP-601 series with active stability due to the stability pattern are presented.

  4. 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)

  5. 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)

  6. Tomographic multiphase flow measurement

    International Nuclear Information System (INIS)

    Sætre, C.; Johansen, G.A.; Tjugum, S.A.

    2012-01-01

    Measurement of multiphase flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain (). These are related to reducing measurement uncertainties arising from variations in the flow regime, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. This work focuses on the first two issues using multi gamma beam (MGB) measurements for identification of the type of flow regime. Further gamma ray tomographic measurements are used for reference of the gas/liquid distribution. For the MGB method one Am-241 source with principal emission at 59.5 keV is used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as compact detectors. One detector is placed diametrically opposite the source whereas the second is positioned to the side so that this beam is close to the pipe wall. The principle is then straight forward to compare the measured intensities of these detectors and through that identify the flow pattern, i.e. the instantaneous cross-sectional gas-liquid distribution. The measurement setup also includes Compton scattering measurements, which can provide information about the changes in the water salinity for flow segments with high water liquid ratio and low gas fractions. By measuring the transmitted intensity in short time slots (<100ms), rapid regime variations are revealed. From this we can select the time sections suitable for salinity measurements. Since the salinity variations change at the time scale of hours, a running average can be performed to increase the accuracy of the measurements. Recent results of this work will be presented here. - Highlights: ► Multiphase flow gas-fraction and flow regime measurements by multi gamma ray beams. ► High-speed gamma ray tomograph as reference for the flow pattern and gas fraction. ► Dual modality

  7. Tomographic multiphase flow measurement

    Energy Technology Data Exchange (ETDEWEB)

    Saetre, C., E-mail: camilla@ift.uib.no [Department of Physics and Technology, University of Bergen (Norway); Michelsen Centre for Industrial Measurement Science and Technology (Norway); Johansen, G.A. [Department of Physics and Technology, University of Bergen (Norway); Michelsen Centre for Industrial Measurement Science and Technology (Norway); Tjugum, S.A. [Michelsen Centre for Industrial Measurement Science and Technology (Norway); Roxar Flow Measurement, Bergen (Norway)

    2012-07-15

    Measurement of multiphase flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain (). These are related to reducing measurement uncertainties arising from variations in the flow regime, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. This work focuses on the first two issues using multi gamma beam (MGB) measurements for identification of the type of flow regime. Further gamma ray tomographic measurements are used for reference of the gas/liquid distribution. For the MGB method one Am-241 source with principal emission at 59.5 keV is used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as compact detectors. One detector is placed diametrically opposite the source whereas the second is positioned to the side so that this beam is close to the pipe wall. The principle is then straight forward to compare the measured intensities of these detectors and through that identify the flow pattern, i.e. the instantaneous cross-sectional gas-liquid distribution. The measurement setup also includes Compton scattering measurements, which can provide information about the changes in the water salinity for flow segments with high water liquid ratio and low gas fractions. By measuring the transmitted intensity in short time slots (<100ms), rapid regime variations are revealed. From this we can select the time sections suitable for salinity measurements. Since the salinity variations change at the time scale of hours, a running average can be performed to increase the accuracy of the measurements. Recent results of this work will be presented here. - Highlights: Black-Right-Pointing-Pointer Multiphase flow gas-fraction and flow regime measurements by multi gamma ray beams. Black-Right-Pointing-Pointer High-speed gamma ray tomograph as reference for the flow

  8. The use of computed tomographic three-dimensional reconstructions to develop instructional models for equine pelvic ultrasonography.

    Science.gov (United States)

    Whitcomb, Mary Beth; Doval, John; Peters, Jason

    2011-01-01

    Ultrasonography has gained increased utility to diagnose pelvic fractures in horses; however, internal pelvic contours can be difficult to appreciate from external palpable landmarks. We developed three-dimensional (3D) simulations of the pelvic ultrasonographic examination to assist with translation of pelvic contours into two-dimensional (2D) images. Contiguous 1mm transverse computed tomography (CT) images were acquired through an equine femur and hemipelvis using a single slice helical scanner. 3D surface models were created using a DICOM reader and imported into a 3D modeling and animation program. The bone models were combined with a purchased 3D horse model and the skin made translucent to visualize pelvic surface contours. 3D models of ultrasound transducers were made from reference photos, and a thin sector shape was created to depict the ultrasound beam. Ultrasonographic examinations were simulated by moving transducers on the skin surface and rectally to produce images of pelvic structures. Camera angles were manipulated to best illustrate the transducer-beam-bone interface. Fractures were created in multiple configurations. Animations were exported as QuickTime movie files for use in presentations coupled with corresponding ultrasound videoclips. 3D models provide a link between ultrasonographic technique and image generation by depicting the interaction of the transducer, ultrasound beam, and structure of interest. The horse model was important to facilitate understanding of the location of pelvic structures relative to the skin surface. While CT acquisition time was brief, manipulation within the 3D software program was time intensive. Results were worthwhile from an instructional standpoint based on user feedback. © 2011 Veterinary Radiology & Ultrasound.

  9. Orthodox representations of God and implicit anthropomorphic reasoning

    Directory of Open Access Journals (Sweden)

    Tatiana Malevich

    2017-12-01

    Full Text Available The phenomenon of theological incorrectness is primarily the result of the coexistence of two parallel levels of religious representations constituting a continuum of cognitive complexity. This article presents results of the replication experiment based on the classical study by J. L. Barrett and F. Keil (1996 aimed at diff erentiating levels of implicit anthropomorphic and explicit non-anthropomorphic reasoning about God. The data which were obtained in the experiment and based on the Russian Orthodox sample of Theology students have confi rmed the cross-cultural universality and stability of the phenomenon of theological incorrectness described by J. L. Barrett and now widely accepted in the cognitive religious science. In a real-thinking mode aimed at rapid solutions to problems, complicated and cognitively cumbersome theological concepts do undergo systematic deformation and optimisation and acquire anthropomorphic properties corresponding to our default ontological assumptions. Such a tacit deformation seems to be independent from theological representations and occurs even in the presence of explicitly held non-anthropomorphic concepts of God.

  10. Monte Carlo Simulations for Homeland Security Using Anthropomorphic Phantoms

    International Nuclear Information System (INIS)

    Burns, Kimberly A.

    2008-01-01

    A radiological dispersion device (RDD) is a device which deliberately releases radioactive material for the purpose of causing terror or harm. In the event that a dirty bomb is detonated, there may be airborne radioactive material that can be inhaled as well as settle on an individuals leading to external contamination. Monte Carlo calculations were performed to simulate healthcare workers in the operating room or trauma room at a hospital. The Monte Carlo Neutral Particle transport code MCNP5 was used for the modeling. The human body was modeled using Medical Internal Radiation Dose (MIRD-V) anthropomorphic phantoms originally developed at Oak Ridge National Laboratory (ORNL) under the specifications of International Commission on Radiation Protection (ICRP) Publication 23 and later altered at Georgia Tech (17). This study considered two possible contamination scenarios: uniform external contamination with no internal contamination and inhaled radioactive material without any external contamination. For both scenarios, the patients isotopes considered were 60 Co, 137 Cs, 131 I, 192 Ir, and 241 Am. For the externally contaminated patient, a uniform volume source two millimeters thick was placed around the skin of each anthropomorphic phantom to simulate a uniform source on the surface of the body. For the internally contaminated patients, the Dose and Risk Calculation software, DCAL, was used to determine the distribution of the isotopes in the internal organs. For both of the scenarios, the healthcare provider was placed 20-cm from the middle of the torso of the contaminated patient. The amount of energy deposited to the tissues and organs of the healthcare provider due to the internally and externally contaminated patients and in the patient in the case of external contamination was determined. The effective dose rate was calculated using the masses of the tissues and organ and tissue weighting factors from ICRP Publication 60. The effective dose rate for the

  11. Computed tomographic colonography to screen for colorectal cancer, extracolonic cancer, and aortic aneurysm: model simulation with cost-effectiveness analysis.

    Science.gov (United States)

    Hassan, Cesare; Pickhardt, Perry J; Pickhardt, Perry; Laghi, Andrea; Kim, Daniel H; Kim, Daniel; Zullo, Angelo; Iafrate, Franco; Di Giulio, Lorenzo; Morini, Sergio

    2008-04-14

    In addition to detecting colorectal neoplasia, abdominal computed tomography (CT) with colonography technique (CTC) can also detect unsuspected extracolonic cancers and abdominal aortic aneurysms (AAA).The efficacy and cost-effectiveness of this combined abdominal CT screening strategy are unknown. A computerized Markov model was constructed to simulate the occurrence of colorectal neoplasia, extracolonic malignant neoplasm, and AAA in a hypothetical cohort of 100,000 subjects from the United States who were 50 years of age. Simulated screening with CTC, using a 6-mm polyp size threshold for reporting, was compared with a competing model of optical colonoscopy (OC), both without and with abdominal ultrasonography for AAA detection (OC-US strategy). In the simulated population, CTC was the dominant screening strategy, gaining an additional 1458 and 462 life-years compared with the OC and OC-US strategies and being less costly, with a savings of $266 and $449 per person, respectively. The additional gains for CTC were largely due to a decrease in AAA-related deaths, whereas the modeled benefit from extracolonic cancer downstaging was a relatively minor factor. At sensitivity analysis, OC-US became more cost-effective only when the CTC sensitivity for large polyps dropped to 61% or when broad variations of costs were simulated, such as an increase in CTC cost from $814 to $1300 or a decrease in OC cost from $1100 to $500. With the OC-US approach, suboptimal compliance had a strong negative influence on efficacy and cost-effectiveness. The estimated mortality from CT-induced cancer was less than estimated colonoscopy-related mortality (8 vs 22 deaths), both of which were minor compared with the positive benefit from screening. When detection of extracolonic findings such as AAA and extracolonic cancer are considered in addition to colorectal neoplasia in our model simulation, CT colonography is a dominant screening strategy (ie, more clinically effective and more cost

  12. Anthropomorphism in Human–Robot Co-evolution

    Directory of Open Access Journals (Sweden)

    Luisa Damiano

    2018-03-01

    Full Text Available Social robotics entertains a particular relationship with anthropomorphism, which it neither sees as a cognitive error, nor as a sign of immaturity. Rather it considers that this common human tendency, which is hypothesized to have evolved because it favored cooperation among early humans, can be used today to facilitate social interactions between humans and a new type of cooperative and interactive agents – social robots. This approach leads social robotics to focus research on the engineering of robots that activate anthropomorphic projections in users. The objective is to give robots “social presence” and “social behaviors” that are sufficiently credible for human users to engage in comfortable and potentially long-lasting relations with these machines. This choice of ‘applied anthropomorphism’ as a research methodology exposes the artifacts produced by social robotics to ethical condemnation: social robots are judged to be a “cheating” technology, as they generate in users the illusion of reciprocal social and affective relations. This article takes position in this debate, not only developing a series of arguments relevant to philosophy of mind, cognitive sciences, and robotic AI, but also asking what social robotics can teach us about anthropomorphism. On this basis, we propose a theoretical perspective that characterizes anthropomorphism as a basic mechanism of interaction, and rebuts the ethical reflections that a priori condemns “anthropomorphism-based” social robots. To address the relevant ethical issues, we promote a critical experimentally based ethical approach to social robotics, “synthetic ethics,” which aims at allowing humans to use social robots for two main goals: self-knowledge and moral growth.

  13. Anthropomorphism in Human–Robot Co-evolution

    Science.gov (United States)

    Damiano, Luisa; Dumouchel, Paul

    2018-01-01

    Social robotics entertains a particular relationship with anthropomorphism, which it neither sees as a cognitive error, nor as a sign of immaturity. Rather it considers that this common human tendency, which is hypothesized to have evolved because it favored cooperation among early humans, can be used today to facilitate social interactions between humans and a new type of cooperative and interactive agents – social robots. This approach leads social robotics to focus research on the engineering of robots that activate anthropomorphic projections in users. The objective is to give robots “social presence” and “social behaviors” that are sufficiently credible for human users to engage in comfortable and potentially long-lasting relations with these machines. This choice of ‘applied anthropomorphism’ as a research methodology exposes the artifacts produced by social robotics to ethical condemnation: social robots are judged to be a “cheating” technology, as they generate in users the illusion of reciprocal social and affective relations. This article takes position in this debate, not only developing a series of arguments relevant to philosophy of mind, cognitive sciences, and robotic AI, but also asking what social robotics can teach us about anthropomorphism. On this basis, we propose a theoretical perspective that characterizes anthropomorphism as a basic mechanism of interaction, and rebuts the ethical reflections that a priori condemns “anthropomorphism-based” social robots. To address the relevant ethical issues, we promote a critical experimentally based ethical approach to social robotics, “synthetic ethics,” which aims at allowing humans to use social robots for two main goals: self-knowledge and moral growth. PMID:29632507

  14. Bisphosphonate effects in rat unloaded hindlimb bone loss model: three-dimensional microcomputed tomographic, histomorphometric, and densitometric analyses.

    Science.gov (United States)

    Barou, O; Lafage-Proust, M H; Martel, C; Thomas, T; Tirode, F; Laroche, N; Barbier, A; Alexandre, C; Vico, L

    1999-10-01

    The effects of antiresorptive drugs on bone loss remain unclear. Using three-dimensional microtomography, dual X-ray/densitometry, and histomorphometry, we evaluated tiludronate effects in the bone loss model of immobilization in tail-suspended rats after 7, 13, and 23 days. Seventy-eight 12-week-old Wistar male rats were assigned to 13 groups: 1 baseline group, and for each time point, 1 control group treated with vehicle and three tail-suspended groups treated with either tiludronate (0.5 or 5 mg/kg) or vehicle, administered s. c. every other day, during the last week before sacrifice. In primary spongiosa (ISP), immobilization-induced bone loss plateaued after day 7 and was prevented by tiludronate. In secondary spongiosa (IISP), bone loss appeared at day 13 with a decrease in trabecular thickness and trabecular number (Tb.N) as assessed by three-dimensional microtomography. Osteoclastic parameters did not differ in tail-suspended rats versus control rats, whereas bone formation showed a biphasic pattern: after a marked decrease at day 7, osteoblastic activity and recruitment normalized at days 13 and 23, respectively. At day 23, the 80% decrease in bone mass was fully prevented by high-dose tiludronate with an increase in Tb.N without preventing trabecular thinning. In summary, at day 7, tiludronate prevented bone loss in ISP. After day 13, tiludronate prevented bone loss in ISP and IISP despite a further decrease in bone formation. Thus, the preventive effects of tiludronate in this model may be related to the alteration in bone modeling with an increase in Tb.N in ISP and subsequently in IISP.

  15. The baboon model under anaesthesia for in vivo cerebral blood flow studies using single photon emission computed tomographic (SPECT) techniques

    International Nuclear Information System (INIS)

    Dormehl, I.; Redelinghuys, F.; Hugo, N.; Oliver, D.; Pilloy, W.

    1992-01-01

    Single photon computed tomography of the brain can be useful in animal experimentation directed towards cerebral conditions. A well established and understood baboon model, necessarily under anaesthesia, could especially be valuable in such investigations. Six normal baboons were studied under various anesthetic agents and their combinations: ketamine, thiopentone, pentobarbitone and halothane. Cerebral blood flow (CBF) studies were performed with 99m Tc-HMPAO. CBF effects from various anaesthesia were detected, requiring careful choice of the anaesthesia for cerebral investigations. (author). 13 refs, 4 figs, 3 tabs

  16. The baboon model under anaesthesia for in vivo cerebral blood flow studies using single photon emission computed tomographic (SPECT) techniques

    Energy Technology Data Exchange (ETDEWEB)

    Dormehl, I.; Redelinghuys, F.; Hugo, N. [Pretoria Univ. (South Africa); Oliver, D.; Pilloy, W. [Medical Univ. of Southern Africa (MEDUNSA), Pretoria (South Africa)

    1992-12-31

    Single photon computed tomography of the brain can be useful in animal experimentation directed towards cerebral conditions. A well established and understood baboon model, necessarily under anaesthesia, could especially be valuable in such investigations. Six normal baboons were studied under various anesthetic agents and their combinations: ketamine, thiopentone, pentobarbitone and halothane. Cerebral blood flow (CBF) studies were performed with {sup 99m}Tc-HMPAO. CBF effects from various anaesthesia were detected, requiring careful choice of the anaesthesia for cerebral investigations. (author). 13 refs, 4 figs, 3 tabs.

  17. 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

  18. The modeling of quadratic B-splines surfaces for the tomographic reconstruction in the FCC- type-riser

    International Nuclear Information System (INIS)

    Vasconcelos, Geovane Vitor; Dantas, Carlos Costa; Melo, Silvio de Barros; Pires, Renan Ferraz

    2009-01-01

    The 3D tomography reconstruction has been a profitable alternative in the analysis of the FCC-type- riser (Fluid Catalytic Cracking), for appropriately keeping track of the sectional catalyst concentration distribution in the process of oil refining. The method of tomography reconstruction proposed by M. Azzi and colleagues (1991) uses a relatively small amount of trajectories (from 3 to 5) and projections (from 5 to 7) of gamma rays, a desirable feature in the industrial process tomography. Compared to more popular methods, such as the FBP (Filtered Back Projection), which demands a much higher amount of gamma rays projections, the method by Azzi et al. is more appropriate for the industrial process, where the physical limitations and the cost of the process require more economical arrangements. The use of few projections and trajectories facilitates the diagnosis in the flow dynamical process. This article proposes an improvement in the basis functions introduced by Azzi et al., through the use of quadratic B-splines functions. The use of B-splines functions makes possible a smoother surface reconstruction of the density distribution, since the functions are continuous and smooth. This work describes how the modeling can be done. (author)

  19. Procedures of hepatic scintigraphy and improvement of professionals by using anthropomorphic simulator object of liver in nuclear medicine; Procedimentos de cintilografia hepatica e aperfeicoamento de profissionais utilizando objeto simulador antropomorfico de figado em medicina nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Fernanda C.L.; Cunha, Cledison J.; Dullius, Marcos A.; Souza, Divanizia N., E-mail: divanizi@ufs.b [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil)

    2011-10-26

    This paper evaluates hepatic scintigraphy procedures and the possibility of professional improvement in nuclear medicine by using three-dimension anthropomorphic simulators representative of adult human liver. For the conformation of anthropomorphic simulator, it was used gypsum and acrylic. Three simulator objects representing cirrhosis livers. The simulator were filled with {sup 99m}Tc diluted in water for the obtention of scintigraphic images. Tomographic images were analysed posterior and anterior of simulator representing an organ with more cirrhosis grade. It was observed that the simulators make possible the acquisition of images similar to the real images of liver with hepatic cirrhosis. The simulations of hemangiomas can contribute for continuous education of nuclear medicine professionals, as far the question of image formation is concerned, make possible the parameter study as, for example, the , matrix size energy window, zoom and counting statistic

  20. 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.

  1. Evolution of prehension ability in an anthropomorphic neurorobotic arm

    Directory of Open Access Journals (Sweden)

    Gianluca Massera

    2007-11-01

    Full Text Available In this paper, we show how a simulated anthropomorphic robotic arm controlled by an artificial neural network can develop effective reaching and grasping behaviour through a trial and error process in which the free parameters encode the control rules which regulate the fine-grained interaction between the robot and the environment and variations of the free parameters are retained or discarded on the basis of their effects at the level of the global behaviour exhibited by the robot situated in the environment. The obtained results demonstrate how the proposed methodology allows the robot to produce effective behaviours thanks to its ability to exploit the morphological properties of the robot's body (i.e. its anthropomorphic shape, the elastic properties of its muscle-like actuators and the compliance of its actuated joints and the properties which arise from the physical interaction between the robot and the environment mediated by appropriate control rules.

  2. JUNGIAN GENDER IN ANIMAL ANIMATION FROM ANTHROPOMORPHISM PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Yustin Sartika

    2017-12-01

    Full Text Available Bear is usually depicted as a strong, brawny and blood-curdling animal. On the contrary, Pooh Bear is the fun-loving and caring main character while Masha Bear can handle all house works. Their characteristics can be related to Jungian gender theory which states that man is bisexual having both feminine and masculine sides. A focus on anima animus is established through qualitative research analysis of bear characters' actions and the characters around within the plots of Winnie-the-Pooh and Masha and the Bear. Masha and the Bear is adapted from the real story in Russia. The use of anthropomorphic storytelling in those animations can bridge the conceptual and moral gulf which separate human from animal. By using anthropomorphism perspective, this research is aimed to find the feminine and masculine stereotype of Pooh and Bear characters. Anthropomorphism is divided into the animation of physical and psychological qualities. The result shows that small bright yellow body on a short red t-shirt makes Pooh look more lovable. Another woman stereotype is portrayed from the name given, Winnie, and his most favorite honey. Masha Bear‘s physical qualities are quite identical to a real bear. Beyond his strong and brawny body, he is a spick-and-span bear. He is a merciful bear who becomes a caregiver for Masha, the parentless girl. Anthropomorphism creates great empathy in humans. This empathy can be combined with a simplified narrative to provoke genuine feeling from audiences. It draws attention to feminine and masculine stereotype of human to identify in animal animation.

  3. Stability Study of Anthropomorphic Robot Antares under External Load Action

    Science.gov (United States)

    Kodyakov, A. S.; Pavlyuk, N. A.; Budkov, V. Yu; Prakapovich, R. A.

    2017-01-01

    The paper presents the study of the behavior of the major structural elements of the lower limbs of anthropomorphic robot Antares under the influence of different types of loads (torsion, fracture). We have determined the required values for actuators torques for motion of the robot in space. The maximum values of torques are 5 Nm and 5.2 Nm respectively, and are able to withstand the upper and lower leg structures.

  4. 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

  5. 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)

  6. Too humanlike to increase my appetite: Disposition to anthropomorphize animals relates to decreased meat consumption through empathic concern.

    Science.gov (United States)

    Niemyjska, Aleksandra; Cantarero, Katarzyna; Byrka, Katarzyna; Bilewicz, Michał

    2018-04-12

    People who exclude meat from their diets are not only devoid of situational pressures to disengage morally and deny humanlike mental states to animals but also they may be dispositionally more inclined to ascribe human-like qualities to non-human animals than omnivores. The aim of this research was to test whether individual differences in anthropomorphism are related to empathic connection with non-human animals and hence decreased meat consumption. In two studies (N = 588) we confirmed that decreased meat consumption was associated with both increased recognition of human features of animals and increased empathy to animals. Most importantly, our data support a model in which animals' anthropomorphism predicts empathy. Empathy, in turn, increases the importance that potential animal harm plays in dietary choices regarding meat, leading to reduced meat consumption. Copyright © 2018. Published by Elsevier Ltd.

  7. Are anthropomorphic persuasive appeals effective? The role of the recipient's motivations.

    Science.gov (United States)

    Tam, Kim-Pong

    2015-03-01

    Anthropomorphic persuasive appeals are prevalent. However, their effectiveness has not been well studied. The present research addresses this issue with two experiments in the context of environmental persuasion. It shows that anthropomorphic messages, relative to non-anthropomorphic ones, appear to motivate more conservation behaviour and elicit more favourable message responses only among recipients who have a strong need for effectance or social connection. Among recipients whose such need is weak, anthropomorphic appeals seem to backfire. These findings extend the research on motivation and persuasion and add evidence to the motivational bases of anthropomorphism. In addition, joining some recent studies, the present research highlights the implications of anthropomorphism of nature for environmental conservation efforts, and offers some practical suggestions for environmental persuasion. © 2014 The British Psychological Society.

  8. Augmenting Locomotion in an Anthropomorphic System

    Directory of Open Access Journals (Sweden)

    Derek Wight

    2005-02-01

    Full Text Available A powered orthosis has applications ranging from assisting the elderly to augmenting astronauts. An assistive control scheme is developed that uses the force from a slave actuator to augment the force of a master actuator. This can be used to augment a closed-loop control scheme applied to the master actuator. Initially, actuator augmentation is explored both theoretically and experimentally using a simple mechanical system. The control scheme is then applied to a scale model of human lower limbs on a stationary bicycle to investigate the feasibility of a powered orthosis using pneumatic muscle actuators.

  9. How gestures affect students: A comparative experiment using class presentations conducted by an anthropomorphic agent

    Science.gov (United States)

    Shirakawa, Tomohiro; Sato, Hiroshi; Imao, Tomoya

    2017-07-01

    Recently, a variety of user interfaces have been developed based on human-robot and human-agent interaction, and anthropomorphic agents are used as one type of interface. However, the use of anthropomorphic agents is applied mainly to the medical and cognitive sciences, and there are few studies of their application to other fields. Therefore, we used an anthropomorphic agent of MMD in a virtual lecture to analyze the effect of gestures on students and search for ways to apply anthropomorphic agents to the field of educational technology.

  10. Computed tomographic appearances of cherubism

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, S D; Boccardi, A; Mela, F; Romagnoli, R

    1987-01-01

    The computed tomographic (CT) aspects of six cases of cherubism are described. Through its optimal representation of the lesions, CT enabled certain characteristics of this disease to be substantiated, namely, limitation of the process to the bones of the jaw and primarily superficial development of the mandibular lesions, coupled with an unusual mandibular condylar impairment. Moreover, the composition of this series permitted investigation of the condition in its several stages of progression.

  11. Caveats on tomographic images

    DEFF Research Database (Denmark)

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

    2014-01-01

    )CNR – Istituto di Geologia Ambientale e Geoingegneria (IGAG) c/o Dipartimento di Scienze della Terra, Università degliStudi di Roma La Sapienza, Rome, Italy, (10) Dept. Physics of the Earth, Sankt-Petersburg State University, Sankt-Petersburg,RussiaGeological models of the mantle and its geodynamic...

  12. 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...

  13. Leap Motion Device Used to Control a Real Anthropomorphic Gripper

    Directory of Open Access Journals (Sweden)

    Ionel Staretu

    2016-06-01

    Full Text Available This paper presents for the first time the use of the Leap Motion device to control an anthropomorphic gripper with five fingers. First, a description of the Leap Motion device is presented, highlighting its main functional characteristics, followed by testing of its use for capturing the movements of a human hand's fingers in different configurations. Next, the HandCommander soft module and the Interface Controller application are described. The HandCommander is a software module created to facilitate interaction between a human hand and the GraspIT virtual environment, and the Interface Controller application is required to send motion data to the virtual environment and to test the communication protocol. For the test, a prototype of an anthropomorphic gripper with five fingers was made, including a proper hardware system of command and control, which is briefly presented in this paper. Following the creation of the prototype, the command system performance test was conducted under real conditions, evaluating the recognition efficiency of the objects to be gripped and the efficiency of the command and control strategies for the gripping process. The gripping test is exemplified by the gripping of an object, such as a screw spanner. It was found that the command system, both in terms of capturing human hand gestures with the Leap Motion device and effective object gripping, is operational. Suggestive figures are presented as examples.

  14. Analysis of Inverse Kinamtics of an Anthropomorphic Robotic hand

    Directory of Open Access Journals (Sweden)

    Pramod Kumar Parida

    2013-03-01

    Full Text Available In this paper, a new method for solving the inverse kinematics of the fingers of an anthropomorphic hand is proposed. Solution of inverse kinematic equations is a complex problem, the complexity comes from the nonlinearity of joint space and Cartesian space mapping and having multiple solutions.This is a typical problem in robotics that needs to be solved to control the fingers of an anthropomorphic robotic hand to perform tasks it is designated to do. With more complex structures operating in a 3-dimensional space deducing a mathematical soluation for the inverse kinematics may prove challenging. In this paper, using the ability of ANFIS (Adaptive Neuro-Fuzzy Inference System to learn from training data, it is possible to create ANFIS network, an implementation of a representative fuzzy inference system using ANFIS structure, with limited mathematical representation of the system. The main advantages of this method with respect to the other methods are implementation is easy, very fast and shorter computation time and better response with acceptable error.

  15. OSL Based Anthropomorphic Phantom and Real-Time Organ Dosimetry

    International Nuclear Information System (INIS)

    Hintenlang, David E.

    2009-01-01

    The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ doses in real-time with a sensitivity that makes it an effective tool for applications in a wide variety of health physics applications. The system included the development of a real-time readout system for fiber optic coupled (FOC) dosimeters that is integrated with a state-of-art anthropomorphic phantom to provide instantaneous measures of organ doses throughout the phantom. The small size of the FOC detectors and optical fibers allow the sensitive volume of the detector to be located at organ centroids (or multiple locations distributed through the organ) within a tissue equivalent, anthropomorphic phantom without perturbing the tissue equivalent features of the phantom. The developed phantom/dosimetry system can be used in any environment where personnel may be exposed to gamma or x-ray radiations to provide the most accurate determinations of organ and effective doses possible to date

  16. OSL Based Anthropomorphic Phantom and Real-Time Organ Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    David E. Hintenlang, Ph.D

    2009-02-10

    The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ does in real-time with a sensitivity that makes it an effective tool for applications in a wide variety of health physics applications. The system included the development of a real-time readout system for fiber optic coupled (FOC) dosimeters that is integrated with a state-of-art anthropomorphic phantom to provide instantaneous measures of organ doses throughout the phantom. The small size of the FOC detectors and optical fibers allow the sensitive volume of the detector to be located at organ centroids (or multiple locations distributed through the organ) within a tissue equivalent, anthropomorphic phantom without perturbing the tissue equivalent features of the phantom. The developed phantom/dosimetry system can be used in any environment where personnel may be exposed to gamma or x-ray radiations to provide the most accurate determinations of organ and effective doses possible to date.

  17. Using Animals to Teach Children Biology: Exploring the Use of Biological Explanations in Children's Anthropomorphic Storybooks

    Science.gov (United States)

    Geerdts, Megan; Van De Walle, Gretchen; LoBue, Vanessa

    2016-01-01

    Research Findings: Anthropomorphism--the attribution of human characteristics to nonhuman entities--has long been a staple of children's media. However, children's experiences with anthropomorphic media may interfere with biological reasoning instead encouraging an anthropocentric view of the natural world. To date, little research has addressed…

  18. The ultimatum game as measurement tool for anthropomorphism in human-robot interaction

    NARCIS (Netherlands)

    Torta, E.; Dijk, van E.T.; Ruijten, P.A.M.; Cuijpers, R.H.; Herrmann, G.; Pearson, M.J.; Lenz, A.; et al., xx

    2013-01-01

    Anthropomorphism is the tendency to attribute human characteristics to non–human entities. This paper presents exploratory work to evaluate how human responses during the ultimatum game vary according to the level of anthropomorphism of the opponent, which was either a human, a humanoid robot or a

  19. Anthropomorphically Speaking: On Communication between Teachers and Children in Early Childhood Biology Education

    Science.gov (United States)

    Thulin, Susanne; Pramling, Niklas

    2009-01-01

    In this study a particular kind of figurative language, so-called anthropomorphic speech, is analysed in the context of science activities in a preschool setting. Anthropomorphism means speaking about something non-human in human terms. Can any systematic pattern be seen with regard to when such speech is used? Do children and/or teachers…

  20. Do storybooks with anthropomorphized animal characters promote prosocial behaviors in young children?

    Science.gov (United States)

    Larsen, Nicole E; Lee, Kang; Ganea, Patricia A

    2018-05-01

    For millennia, adults have told children stories not only to entertain but also to impart important moral lessons to promote prosocial behaviors. Many such stories contain anthropomorphized animals because it is believed that children learn from anthropomorphic stories as effectively, if not better than, from stories with human characters, and thus are more inclined to act according to the moral lessons of the stories. Here we experimentally tested this belief by reading preschoolers a sharing story with either human characters or anthropomorphized animal characters. Reading the human story significantly increased preschoolers' altruistic giving but reading the anthropomorphic story or a control story decreased it. Thus, contrary to the common belief, realistic stories, not anthropomorphic ones, are better for promoting young children's prosocial behavior. © 2017 John Wiley & Sons Ltd.

  1. 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)

  2. Low-cost design and fabrication of an anthropomorphic robotic hand.

    Science.gov (United States)

    Junaid, Ali Bin; Tahir, Sanan; Rasheed, Tahir; Ahmed, Sharjeel; Sohail, Mehreen; Afzal, Muhammad Raheel; Ali, Muzaffar; Kim, Yoonsoo

    2014-10-01

    Human hand signifies a magnificent and challenging example for scientists and engineers trying to replicate its complex structure and functionality. This paper proposes a bio-mechatronic approach for the design of an anthropomorphic artificial hand capable of performing basic human hand motions with fundamental gripping functionality. The dexterity of the artificial hand is exhibited by imitating the natural motion of the human fingers. Imitation is produced according to the data acquired from the flex sensors attached to the human fingers. In order to have proper gripping, closed-loop control is implemented using the tactile sensors. Feedback for the closed-loop control is provided by force sensing resistors (FSRs), attached on the fingertips of the robotic hand. These sensors also enable handling of fragile objects. The mathematical model is derived using forward kinematics and also simulated on MATLAB to ascertain the position of robotic fingers in 3D space.

  3. Computer tomographic examinations in epilepsy

    International Nuclear Information System (INIS)

    De Villiers, J.F.K.

    1984-01-01

    Epileptic patients that was examined at the Universitas Hospital (Bloemfontein) by means of computerized tomography for the period July 1978 - December 1980, are divided into two groups: a) Patients with general epilepsy of convulsions - 507; b) Patients with vocal or partial epilepsy - 111. The method of examination and the results for both general and vocal epilepsy are discussed. A degenerative state was found in 35% of the positive computer tomographic examinations in general epilepsy and 22% of the positive examinations for vocal epilepsy. The purpose of the article was to explain the circumstances that can be expected when a epileptic patient is examined by means of computerized tomography

  4. Ovarian metastases: Computed tomographic appearances

    International Nuclear Information System (INIS)

    Megibow, A.J.; Hulnick, D.H.; Bosniak, M.A.; Balthazar, E.J.

    1985-01-01

    Computed tomographic scans of 34 patients with ovarian metastases were reviewed to assess the radiographic appearances and to correlate these with the primary neoplasms. Primary neoplasms were located in the colon (20 patients), breast (six), stomach (five), small bowel (one), bladder (one), and Wilms tumor of the kidney (one). The radiographic appearance of the metastatic lesions could be described as predominantly cystic (14 lesions), mixed (12 lesions), or solid (seven lesions). The cystic and mixed lesions tended to be larger in overall diameter than the solid. The metastases from gastric carcinoma appeared solid in four of five cases. The metastases from the other neoplasms had variable appearances simulating primary ovarian carcinoma

  5. 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.

  6. 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.))

  7. 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.))

  8. 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)

  9. Using Anthropomorphism and Fictional Story Development to Enhance Student Learning

    Directory of Open Access Journals (Sweden)

    Kari A. Brossard Stoos

    2017-05-01

    Full Text Available Understanding mechanisms of human disease can be very challenging for students with a basic background in anatomy and biology, and it can be nearly impossible for students without any prior exposure to these basic sciences.  We have designed an approach for understanding human disease for learners of various science backgrounds.  By using fictional character associations with disease processes, we have anthropomorphized disease components to make the mechanisms accessible to students with little to no science background, while still appealing and exciting to students with significant science backgrounds.  By assisting students in the creation of fictional characters to represent disease processes, we have increased student understanding, engagement, enjoyment, and retention of course content.

  10. Anthropomorphism in the search for extra-terrestrial intelligence - The limits of cognition?

    Science.gov (United States)

    Bohlmann, Ulrike M.; Bürger, Moritz J. F.

    2018-02-01

    The question "Are we alone?" lingers in the human mind since ancient times. Early human civilisations populated the heavens above with a multitude of Gods endowed with some all too human characteristics - from their outer appearance to their innermost motivations. En passant they created thereby their own cultural founding myths on which they built their understanding of the world and its phenomena and deduced as well rules for the functioning of their own society. Advancing technology has enabled us to conduct this human quest for knowledge with more scientific means: optical and radio-wavelengths are being monitored for messages by an extra-terrestrial intelligence and active messaging attempts have also been undertaken. Scenarios have been developed for a possible detection of extra-terrestrial intelligence and post-detection guidelines and protocols have been elaborated. The human responses to the whole array of questions concerning the potential existence, discovery of and communication/interaction with an extra-terrestrial intelligence share as one clear thread a profound anthropomorphism, which ascribes classical human behavioural patterns also to an extra-terrestrial intelligence in much the same way as our ancestors attributed comparable conducts to mythological figures. This paper aims at pinpointing this thread in a number of classical reactions to basic questions related to the search for extra-terrestrial intelligence. Many of these reactions are based on human motives such as curiosity and fear, rationalised by experience and historical analogy and modelled in the Science Fiction Culture by literature and movies. Scrutinising the classical hypothetical explanations of the Fermi paradox under the angle of a potentially undue anthropomorphism, this paper intends to assist in understanding our human epistemological limitations in the search for extra-terrestrial intelligence. This attempt is structured into a series of questions: I. Can we be alone? II

  11. SU-E-T-124: Anthropomorphic Phantoms for Confirmation of Linear Accelerator Based Small Animal Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Perks, J; Benedict, S [UC Davis Cancer Center, Sacramento, CA (United States); Lucero, S [UC Davis, Davis, CA (United States)

    2015-06-15

    Purpose: To document the support of radiobiological small animal research by a modern radiation oncology facility. This study confirms that a standard, human use linear accelerator can cover the range of experiments called for by researchers performing animal irradiation. A number of representative, anthropomorphic murine phantoms were made. The phantoms confirmed the small field photon and electron beams dosimetry validated the use of the linear accelerator for rodents. Methods: Laser scanning a model, CAD design and 3D printing produced the phantoms. The phantoms were weighed and CT scanned to judge their compatibility to real animals. Phantoms were produced to specifically mimic lung, gut, brain, and othotopic lesion irradiations. Each phantom was irradiated with the same protocol as prescribed to the live animals. Delivered dose was measured with small field ion chambers, MOS/FETs or TLDs. Results: The density of the phantom material compared to density range across the real mice showed that the printed material would yield sufficiently accurate measurements when irradiated. The whole body, lung and gut irradiations were measured within 2% of prescribed doses with A1SL ion chamber. MOSFET measurements of electron irradiations for the orthotopic lesions allowed refinement of the measured small field output factor to better than 2% and validated the immunology experiment of irradiating one lesion and sparing another. Conclusion: Linacs are still useful tools in small animal bio-radiation research. This work demonstrated a strong role for the clinical accelerator in small animal research, facilitating standard whole body dosing as well as conformal treatments down to 1cm field. The accuracy of measured dose, was always within 5%. The electron irradiations of the phantom brain and flank tumors needed adjustment; the anthropomorphic phantoms allowed refinement of the initial output factor measurements for these fields which were made in a large block of solid water.

  12. Design and fabrication of a realistic anthropomorphic heterogeneous head phantom for MR purposes.

    Directory of Open Access Journals (Sweden)

    Sossena Wood

    Full Text Available The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications.An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application that involves electromagnetic-tissue interactions: MRI (due to it being an available resource. The developed phantom was filled with media possessing electromagnetic constitutive parameters that correspond to biological tissues at ~297 MHz. A preliminary comparison between an in-vivo human volunteer (based on whom the anthropomorphic head phantom was created and various phantoms types, one being the anthropomorphic heterogeneous head phantom, were performed using a 7 Tesla human MRI scanner.Echo planar imaging was performed and minimal ghosting and fluctuations were observed using the proposed anthropomorphic phantom. The magnetic field distributions (during MRI experiments at 7 Tesla and the scattering parameter (measured using a network analyzer were most comparable between the anthropomorphic heterogeneous head phantom and an in-vivo human volunteer.The developed anthropomorphic heterogeneous head phantom can be used as a resource to various researchers in applications that involve electromagnetic-biological tissue interactions such as MRI.

  13. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    International Nuclear Information System (INIS)

    Batista Nogueira, Luciana; Lemos Silva, Hugo Leonardo; Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio

    2015-01-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm 2 each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the prescribed

  14. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Batista Nogueira, Luciana [Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Lemos Silva, Hugo Leonardo [Santa Casa Hospital, Belo Horizonte (Brazil); Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil)

    2015-07-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm{sup 2} each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the

  15. Positron emission tomography/computed tomographic and magnetic resonance imaging in a murine model of progressive atherosclerosis using (64)Cu-labeled glycoprotein VI-Fc.

    Science.gov (United States)

    Bigalke, Boris; Phinikaridou, Alkystis; Andia, Marcelo E; Cooper, Margaret S; Schuster, Andreas; Schönberger, Tanja; Griessinger, Christoph M; Wurster, Thomas; Onthank, David; Ungerer, Martin; Gawaz, Meinrad; Nagel, Eike; Botnar, Rene M

    2013-11-01

    Plaque erosion leads to exposure of subendothelial collagen, which may be targeted by glycoprotein VI (GPVI). We aimed to detect plaque erosion using (64)Cu-labeled GPVI-Fc (fragment crystallized). Four-week-old male apolipoprotein E-deficient (ApoE(-/-)) mice (n=6) were fed a high-fat diet for 12 weeks. C57BL/6J wild-type (WT) mice served as controls (n=6). Another group of WT mice received a ligation injury of the left carotid artery (n=6) or sham procedure (n=4). All mice received a total activity of ≈12 MBq (64)Cu-GPVI-Fc by tail vein injection followed by delayed (24 hours) positron emission tomography using a NanoPET/computed tomographic scanner (Mediso, Hungary; Bioscan, USA) with an acquisition time of 1800 seconds. Seventy-two hours after positron emission tomography/computed tomography, all mice were scanned 2 hours after intravenous administration of 0.2 mmol/kg body weight of a gadolinium-based elastin-specific MR contrast agent. MRI was performed on a 3-T clinical scanner (Philips Healthcare, Best, The Netherlands). In ApoE(-/-) mice, the (64)Cu-GPVI-Fc uptake in the aortic arch was significantly higher compared with WT mice (ApoE(-/-): 13.2±1.5 Bq/cm(3) versus WT mice: 5.1±0.5 Bq/cm(3); P=0.028). (64)Cu-GPVI-Fc uptake was also higher in the injured left carotid artery wall compared with the intact right carotid artery of WT mice and as a trend compared with sham procedure (injured: 20.7±1.3 Bq/cm(3) versus intact: 2.3±0.5 Bq/cm(3); P=0.028 versus sham: 12.7±1.7 Bq/cm(3); P=0.068). Results were confirmed by ex vivo histology and in vivo MRI with elastin-specific MR contrast agent that measures plaque burden and vessel wall remodeling. Higher R1 relaxation rates were found in the injured carotid wall with a T1 mapping sequence (injured: 1.44±0.08 s(-1) versus intact: 0.91±0.02 s(-1); P=0.028 versus sham: 0.97±0.05 s(-1); P=0.068) and in the aortic arch of ApoE(-/-) mice compared with WT mice (ApoE(-/-): 1.49±0.05 s(-1) versus WT: 0.92±0.04 s

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. Surface Model and Tomographic Archive of Fossil Primate and Other Mammal Holotype and Paratype Specimens of the Ditsong National Museum of Natural History, Pretoria, South Africa.

    Directory of Open Access Journals (Sweden)

    Justin W Adams

    Full Text Available Nearly a century of paleontological excavation and analysis from the cave deposits of the Cradle of Humankind UNESCO World Heritage Site in northeastern South Africa underlies much of our understanding of the evolutionary history of hominins, other primates and other mammal lineages in the late Pliocene and early Pleistocene of Africa. As one of few designated fossil repositories, the Plio-Pleistocene Palaeontology Section of the Ditsong National Museum of Natural History (DNMNH; the former Transvaal Museum curates much of the mammalian faunas recovered from the fossil-rich deposits of major South African hominin-bearing localities, including the holotype and paratype specimens of many primate, carnivore, and other mammal species (Orders Primates, Carnivora, Artiodactyla, Eulipotyphla, Hyracoidea, Lagomorpha, Perissodactyla, and Proboscidea. Here we describe an open-access digital archive of high-resolution, full-color three-dimensional (3D surface meshes of all 89 non-hominin holotype, paratype and significant mammalian specimens curated in the Plio-Pleistocene Section vault. Surface meshes were generated using a commercial surface scanner (Artec Spider, Artec Group, Luxembourg, are provided in formats that can be opened in both open-source and commercial software, and can be readily downloaded either via an online data repository (MorphoSource or via direct request from the DNMNH. In addition to providing surface meshes for each specimen, we also provide tomographic data (both computerized tomography [CT] and microfocus [microCT] for a subset of these fossil specimens. This archive of the DNMNH Plio-Pleistocene collections represents the first research-quality 3D datasets of African mammal fossils to be made openly available. This simultaneously provides the paleontological community with essential baseline information (e.g., updated listing and 3D record of specimens in their current state of preservation and serves as a single resource of

  2. Surface Model and Tomographic Archive of Fossil Primate and Other Mammal Holotype and Paratype Specimens of the Ditsong National Museum of Natural History, Pretoria, South Africa.

    Science.gov (United States)

    Adams, Justin W; Olah, Angela; McCurry, Matthew R; Potze, Stephany

    2015-01-01

    Nearly a century of paleontological excavation and analysis from the cave deposits of the Cradle of Humankind UNESCO World Heritage Site in northeastern South Africa underlies much of our understanding of the evolutionary history of hominins, other primates and other mammal lineages in the late Pliocene and early Pleistocene of Africa. As one of few designated fossil repositories, the Plio-Pleistocene Palaeontology Section of the Ditsong National Museum of Natural History (DNMNH; the former Transvaal Museum) curates much of the mammalian faunas recovered from the fossil-rich deposits of major South African hominin-bearing localities, including the holotype and paratype specimens of many primate, carnivore, and other mammal species (Orders Primates, Carnivora, Artiodactyla, Eulipotyphla, Hyracoidea, Lagomorpha, Perissodactyla, and Proboscidea). Here we describe an open-access digital archive of high-resolution, full-color three-dimensional (3D) surface meshes of all 89 non-hominin holotype, paratype and significant mammalian specimens curated in the Plio-Pleistocene Section vault. Surface meshes were generated using a commercial surface scanner (Artec Spider, Artec Group, Luxembourg), are provided in formats that can be opened in both open-source and commercial software, and can be readily downloaded either via an online data repository (MorphoSource) or via direct request from the DNMNH. In addition to providing surface meshes for each specimen, we also provide tomographic data (both computerized tomography [CT] and microfocus [microCT]) for a subset of these fossil specimens. This archive of the DNMNH Plio-Pleistocene collections represents the first research-quality 3D datasets of African mammal fossils to be made openly available. This simultaneously provides the paleontological community with essential baseline information (e.g., updated listing and 3D record of specimens in their current state of preservation) and serves as a single resource of high

  3. CT images of an anthropomorphic and anthropometric male pelvis phantom

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Andrea S.D. de; Campos, Tarcisio P.R. de, E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares

    2009-07-01

    Actually, among of the most often neoplasm types are the cancer of prostate, bladder and intestine. The incidence of the intestine neoplasm in Brazil is at fourth among the most frequent tumors of the male sex, barely close to the stomach, lung and prostate incidences. Phantoms are objects used as simulators for investigating ionizing radiation transport on humans, especially during radiation therapy or radiological diagnostic. The purpose of this work is the achievement of a set of computerized tomography (CT) images of a male pelvis phantom, with anthropomorphic and anthropometric features. It investigates and analyses the set of phantom CT images in according to a correspondent human pelvis one. The reason to develop a pelvis phantom is the needs of reproducing well established spatial dose distribution in radiation therapy, especially during calibration and protocol setup for various pelvis neoplasms. It aims to produce dose optimization on radiation therapy, improving health tissue protection and keeping control tumor dose. A male pelvis phantom with similar shape made of equivalent tissues was built for simulating the ionizing radiation transport to the human body. At the phantom, pelvis organs were reproduced including the bladder, the intestine, the prostate, the muscular and greasy tissue, as well as the bone tissue and the skin. A set of CT images was carried out in axial thin sections of 2mm thickness. As results, the constituent tissues had a tomography response on Hounsfield scale similar to values found on the human pelvis. Each tissue has its respective Hounsfield value, demonstrated here. The CT images also show that the organs have equivalent anthropometric measures and anthropomorphic features of the radiological human anatomy. The anatomical physical arrangement of the organs is also similar to of the pelvis human male, having the scales of gray and numerical scale of Hounsfield compatible with the scale of the human tissue. The phantom presents

  4. CT images of an anthropomorphic and anthropometric male pelvis phantom

    International Nuclear Information System (INIS)

    Matos, Andrea S.D. de; Campos, Tarcisio P.R. de

    2009-01-01

    Actually, among of the most often neoplasm types are the cancer of prostate, bladder and intestine. The incidence of the intestine neoplasm in Brazil is at fourth among the most frequent tumors of the male sex, barely close to the stomach, lung and prostate incidences. Phantoms are objects used as simulators for investigating ionizing radiation transport on humans, especially during radiation therapy or radiological diagnostic. The purpose of this work is the achievement of a set of computerized tomography (CT) images of a male pelvis phantom, with anthropomorphic and anthropometric features. It investigates and analyses the set of phantom CT images in according to a correspondent human pelvis one. The reason to develop a pelvis phantom is the needs of reproducing well established spatial dose distribution in radiation therapy, especially during calibration and protocol setup for various pelvis neoplasms. It aims to produce dose optimization on radiation therapy, improving health tissue protection and keeping control tumor dose. A male pelvis phantom with similar shape made of equivalent tissues was built for simulating the ionizing radiation transport to the human body. At the phantom, pelvis organs were reproduced including the bladder, the intestine, the prostate, the muscular and greasy tissue, as well as the bone tissue and the skin. A set of CT images was carried out in axial thin sections of 2mm thickness. As results, the constituent tissues had a tomography response on Hounsfield scale similar to values found on the human pelvis. Each tissue has its respective Hounsfield value, demonstrated here. The CT images also show that the organs have equivalent anthropometric measures and anthropomorphic features of the radiological human anatomy. The anatomical physical arrangement of the organs is also similar to of the pelvis human male, having the scales of gray and numerical scale of Hounsfield compatible with the scale of the human tissue. The phantom presents

  5. Do Young Chinese Children Gain Anthropomorphism after Exposure to Personified Touch-Screen and Board Games?

    Science.gov (United States)

    Li, Hui; Hsueh, Yeh; Wang, Fuxing; Bai, Xuejun; Liu, Tao; Zhou, Li

    2017-01-01

    Research shows that preschoolers are likely to anthropomorphize not only animals, but also inanimate toy after being exposed to books that personify these objects. Can such an effect also arise through young children's use of touch-screen games? The present study is the first to examine whether playing a touch-screen personified train game affects young children's anthropomorphism of real trains. Seventy-nine 4- and 6-year-old children were randomly assigned to play either a touch-screen game or a board game of Thomas the Tank Engine for 10 min. They completed the Individual Differences in Anthropomorphism Questionnaire-Child Form (IDAQ-CF) (two subscales: Technology/Inanimate Nature, Animate Nature) and an additional four items about the anthropomorphism of real trains, before (T1) and after (T2) the game. Overall results showed that children manifested a small but statistically significant increase in anthropomorphizing of real trains after their exposure to both games, claiming that real trains were like humans. Interestingly, 4-year-old children in the board game group tended to anthropomorphize real trains more than those in the touch-screen group, whereas the reverse was true for the 6-year-old children. The results suggest that touch-screen games may delay the decline of children's anthropomorphism during the cognitive and socio-emotional transition that occurs in children aged 5-7. These findings have implications for future research on how touch-screen games increase children's anthropomorphism of the real world, and more generally, for evaluation of the influence of the growing use of touch-screen games on young children's learning.

  6. Decision support aids with anthropomorphic characteristics influence trust and performance in younger and older adults.

    Science.gov (United States)

    Pak, Richard; Fink, Nicole; Price, Margaux; Bass, Brock; Sturre, Lindsay

    2012-01-01

    This study examined the use of deliberately anthropomorphic automation on younger and older adults' trust, dependence and performance on a diabetes decision-making task. Research with anthropomorphic interface agents has shown mixed effects in judgments of preferences but has rarely examined effects on performance. Meanwhile, research in automation has shown some forms of anthropomorphism (e.g. etiquette) have effects on trust and dependence on automation. Participants answered diabetes questions with no-aid, a non-anthropomorphic aid or an anthropomorphised aid. Trust and dependence in the aid was measured. A minimally anthropomorphic aide primarily affected younger adults' trust in the aid. Dependence, however, for both age groups was influenced by the anthropomorphic aid. Automation that deliberately embodies person-like characteristics can influence trust and dependence on reasonably reliable automation. However, further research is necessary to better understand the specific aspects of the aid that affect different age groups. Automation that embodies human-like characteristics may be useful in situations where there is under-utilisation of reasonably reliable aids by enhancing trust and dependence in that aid. Practitioner Summary: The design of decision-support aids on consumer devices (e.g. smartphones) may influence the level of trust that users place in that system and their amount of use. This study is the first step in articulating how the design of aids may influence user's trust and use of such systems.

  7. 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...

  8. 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...

  9. 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.)

  10. Impaired spontaneous anthropomorphizing despite intact perception and social knowledge

    Science.gov (United States)

    Heberlein, Andrea S.; Adolphs, Ralph

    2004-01-01

    Humans spontaneously imbue the world with social meaning: we see not only emotions and intentional behaviors in humans and other animals, but also anger in the movements of thunderstorms and willful sabotage in crashing computers. Converging evidence supports a role for the amygdala, a collection of nuclei in the temporal lobe, in processing emotionally and socially relevant information. Here, we report that a patient with bilateral amygdala damage described a film of animated shapes (normally seen as full of social content) in entirely asocial, geometric terms, despite otherwise normal visual perception. Control tasks showed that the impairment did not result from a global inability to describe social stimuli or a bias in language use, nor was a similar impairment observed in eight comparison subjects with damage to orbitofrontal cortex. This finding extends the role of the amygdala to the social attributions we make even to stimuli that are not explicitly social and, in so doing, suggests that the human capacity for anthropomorphizing draws on some of the same neural systems as do basic emotional responses. PMID:15123799

  11. 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

  12. 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.

  13. 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

  14. Development of a patient-specific two-compartment anthropomorphic breast phantom

    International Nuclear Information System (INIS)

    Prionas, Nicolas D; Burkett, George W; McKenney, Sarah E; Chen, Lin; Boone, John M; Stern, Robin L

    2012-01-01

    The purpose of this paper is to develop a technique for the construction of a two-compartment anthropomorphic breast phantom specific to an individual patient's pendant breast anatomy. Three-dimensional breast images were acquired on a prototype dedicated breast computed tomography (bCT) scanner as part of an ongoing IRB-approved clinical trial of bCT. The images from the breast of a patient were segmented into adipose and glandular tissue regions and divided into 1.59 mm thick breast sections to correspond to the thickness of polyethylene stock. A computer-controlled water-jet cutting machine was used to cut the outer breast edge and the internal regions corresponding to glandular tissue from the polyethylene. The stack of polyethylene breast segments was encased in a thermoplastic ‘skin’ and filled with water. Water-filled spaces modeled glandular tissue structures and the surrounding polyethylene modeled the adipose tissue compartment. Utility of the phantom was demonstrated by inserting 200 µm microcalcifications as well as by measuring point dose deposition during bCT scanning. Affine registration of the original patient images with bCT images of the phantom showed similar tissue distribution. Linear profiles through the registered images demonstrated a mean coefficient of determination (r 2 ) between grayscale profiles of 0.881. The exponent of the power law describing the anatomical noise power spectrum was identical in the coronal images of the patient's breast and the phantom. Microcalcifications were visualized in the phantom at bCT scanning. The real-time air kerma rate was measured during bCT scanning and fluctuated with breast anatomy. On average, point dose deposition was 7.1% greater than the mean glandular dose. A technique to generate a two-compartment anthropomorphic breast phantom from bCT images has been demonstrated. The phantom is the first, to our knowledge, to accurately model the uncompressed pendant breast and the glandular tissue

  15. 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

  16. Whole-Body Single-Bed Time-of-Flight RPC-PET: Simulation of Axial and Planar Sensitivities With NEMA and Anthropomorphic Phantoms

    Science.gov (United States)

    Crespo, Paulo; Reis, João; Couceiro, Miguel; Blanco, Alberto; Ferreira, Nuno C.; Marques, Rui Ferreira; Martins, Paulo; Fonte, Paulo

    2012-06-01

    A single-bed, whole-body positron emission tomograph based on resistive plate chambers has been proposed (RPC-PET). An RPC-PET system with an axial field-of-view (AFOV) of 2.4 m has been shown in simulation to have higher system sensitivity using the NEMA NU2-1994 protocol than commercial PET scanners. However, that protocol does not correlate directly with lesion detectability. The latter is better correlated with the planar (slice) sensitivity, obtained with a NEMA NU2-2001 line-source phantom. After validation with published data for the GE Advance, Siemens TruePoint and TrueV, we study by simulation their axial sensitivity profiles, comparing results with RPC-PET. Planar sensitivities indicate that RPC-PET is expected to outperform 16-cm (22-cm) AFOV scanners by a factor 5.8 (3.0) for 70-cm-long scans. For 1.5-m scans (head to mid-legs), the sensitivity gain increases to 11.7 (6.7). Yet, PET systems with large AFOV provide larger coverage but also larger attenuation in the object. We studied these competing effects with both spherical- and line-sources immersed in a 27-cm-diameter water cylinder. For 1.5-m-long scans, the planar sensitivity drops one order of magnitude in all scanners, with RPC-PET outperforming 16-cm (22-cm) AFOV scanners by a factor 9.2 (5.3) without considering the TOF benefit. A gain in the effective sensitivity is expected with TOF iterative reconstruction. Finally, object scatter in an anthropomorphic phantom is similar for RPC-PET and modern, scintillator-based scanners, although RPC-PET benefits further if its TOF information is utilized to exclude scatter events occurring outside the anthropomorphic phantom.

  17. 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

  18. An anthropomorphic transhumeral prosthesis socket developed based on an oscillometric pump and controlled by force-sensitive resistor pressure signals.

    Science.gov (United States)

    Razak, N A Abd; Gholizadeh, H; Hasnan, N; Osman, N A Abu; Fadzil, S S Mohd; Hashim, N A

    2017-02-01

    While considering the importance of the interface between amputees and prosthesis sockets, we study an anthropomorphic prosthesis socket whose size can be dynamically changed according to the requirements of the residual limb. First, we introduce the structure and function of the anthropomorphic prosthesis socket. Second, we study the dynamic model of the prosthesis system and analyze the dynamic characteristics of the prosthesis socket system, the inputs of an oscillometric pump, and the control mechanism of force-sensitive resistor (FSR) pressure signals. Experiments on 10 healthy subjects using the designed system yield an average detection result between 102 and 112 kPa for the FSR pressure sensor and 39 and 41 kPa for the oscillometric pump. Results show the function of the FSR pressure signal in maintaining the contact pressure between the sockets and the residual limb. The potential development of an auto-adjusted socket that uses an oscillometric pump system will provide prosthetic sockets with controllable contact pressure at the residual limb. Moreover, this development is an attractive research area for researchers involved in rehabilitation engineering, prosthetics, and orthotics.

  19. Small anthropomorphic figurines in clay at Ģipka Neolithic settlements

    Directory of Open Access Journals (Sweden)

    Ilze Biruta Loze

    2005-12-01

    Full Text Available Miniature Neolithic figurines in clay are a special topic of research. This especially concerns areas where their representation has so far been poor. While carrying out archaeological excavations in Northern Kurzeme, the north-west coastal dune zone of Rīga Bay, a ritual-like complex was recovered at Ģipka A site belonging to the local Culture of Pit Ceramics. It consists of several large and smaller fireplaces and pits, with the finds of fragmentary clay figurines recovered under the palisade that surrounded the settlement. The head and body of the miniature anthropomorphic figurines in clay have original modelling. It is possible to single out two types of figurine: with rather broad cheekbones, and oval modelling of face. The large amount of ochre found in the settlement and the purposeful breaking of figurines are evidence of their role during a rite. Clay figurines have a symbolic meaning, and the signs depicted on them, incised walking stick-shape and other motifs, are the symbols of early farmers.

  20. Do cavies talk?: The effect of anthropomorphic books on children's knowledge about animals

    Directory of Open Access Journals (Sweden)

    Patricia A Ganea

    2014-04-01

    Full Text Available Many books for young children present animals in fantastical and unrealistic ways, as wearing clothes, talking and engaging in human-like activities. This research examined whether anthropomorphism in children’s books affects children’s learning and conceptions of animals, by specifically assessing the impact of depictions (a bird wearing clothes and reading a book and language (bird described as talking and as having human intentions. In Study 1, 3-, 4-, and 5-year-old children saw picture books featuring realistic drawings of a novel animal. Half of the children also heard factual, realistic language, while the other half heard anthropomorphized language. In Study 2, we replicated the first study using anthropomorphic illustrations of real animals. The results show that the language used to describe animals in books has an effect on children’s tendency to attribute human-like traits to animals, and that anthropomorphic storybooks affect younger children’s learning of novel facts about animals. These results indicate that anthropomorphized animals in books may not only lead to less learning but also influence children’s conceptual knowledge of animals.

  1. Do cavies talk? The effect of anthropomorphic picture books on children's knowledge about animals.

    Science.gov (United States)

    Ganea, Patricia A; Canfield, Caitlin F; Simons-Ghafari, Kadria; Chou, Tommy

    2014-01-01

    Many books for young children present animals in fantastical and unrealistic ways, such as wearing clothes, talking and engaging in human-like activities. This research examined whether anthropomorphism in children's books affects children's learning and conceptions of animals, by specifically assessing the impact of depictions (a bird wearing clothes and reading a book) and language (bird described as talking and as having human intentions). In Study 1, 3-, 4-, and 5-year-old children saw picture books featuring realistic drawings of a novel animal. Half of the children also heard factual, realistic language, while the other half heard anthropomorphized language. In Study 2, we replicated the first study using anthropomorphic illustrations of real animals. The results show that the language used to describe animals in books has an effect on children's tendency to attribute human-like traits to animals, and that anthropomorphic storybooks affect younger children's learning of novel facts about animals. These results indicate that anthropomorphized animals in books may not only lead to less learning but also influence children's conceptual knowledge of animals.

  2. In Vivo Evaluation of 1-O-(4-(2-Fluoroethyl-Carbamoyloxymethyl-2-Nitrophenyl-O-β-D-Glucopyronuronate: A Positron Emission Tomographic Tracer for Imaging β-Glucuronidase Activity in a Tumor/Inflammation Rodent Model

    Directory of Open Access Journals (Sweden)

    Iněs F. Antunes

    2012-01-01

    Full Text Available β-Glucuronidase (β-GUS plays an important role in inflammation and degenerative processes. The enzyme has also been investigated as a target in prodrug therapy for cancer. To investigate the role of β-GUS in pathologies and to optimize β-GUS-based prodrug therapies, we recently developed a positron emission tomographic (PET tracer, 1-O-(4-(2-fluoroethyl-carbamoyloxymethyl-2-nitrophenyl-O-β-D>-glucopyronuronate ([18F]FEAnGA, which proved to be selectively cleaved by β-GUS. Here we present the in vivo evaluation of [18F]FEAnGA for imaging of β-GUS in a tumor/inflammation model. Ex vivo biodistribution of [18F]FEAnGA was conducted in healthy rats. PET imaging and pharmacokinetic modeling were performed in Wistar rats bearing C6 tumors of different sizes and sterile inflammation. The biodistribution studies of [18F]FEAnGA indicated low uptake in major organs and rapid excretion through the renal pathway. MicroPET studies revealed three times higher uptake in the viable part of larger C6 gliomas than in smaller C6 gliomas. Uptake in inflamed muscle was significantly higher than in control muscle. The distribution volume of [18F]FEAnGA in the viable part of the tumor correlated well with the cleavage of the tracer to [18F]fluoroethylamine and the spacer 4-hydroxy-3-nitrobenzyl alcohol. [18F]FEAnGA is a PET tracer able to detect increased activity of β-GUS in large solid tumors and in inflamed tissues.

  3. NURBS-based 3-d anthropomorphic computational phantoms for radiation dosimetry applications

    International Nuclear Information System (INIS)

    Lee, Choonsik; Lodwick, Daniel; Lee, Choonik; Bolch, Wesley E.

    2007-01-01

    Computational anthropomorphic phantoms are computer models used in the evaluation of absorbed dose distributions within the human body. Currently, two classes of the computational phantoms have been developed and widely utilised for dosimetry calculation: (1) stylized (equation-based) and (2) voxel (image-based) phantoms describing human anatomy through the use of mathematical surface equations and 3-D voxel matrices, respectively. However, stylized phantoms have limitations in defining realistic organ contours and positioning as compared to voxel phantoms, which are themselves based on medical images of human subjects. In turn, voxel phantoms that have been developed through medical image segmentation have limitations in describing organs that are presented in low contrast within either magnetic resonance or computed tomography image. The present paper reviews the advantages and disadvantages of these existing classes of computational phantoms and introduces a hybrid approach to a computational phantom construction based on non-uniform rational B-Spline (NURBS) surface animation technology that takes advantage of the most desirable features of the former two phantom types. (authors)

  4. Dose evaluation in occupationally exposed workers through dosimeters ring and wrist type with an anthropomorphic phantom

    International Nuclear Information System (INIS)

    Palma, R.; Gastelo, E.; Paucar, R.; Tolentino, D.; Herrera, J.; Armas, D.

    2014-08-01

    In the Nuclear Medicine service of the Clinica San Pablo (Peru), the occupationally exposed workers carried out the preparation and administration of radiopharmaceuticals to patients, so it is vital to measure the equivalent dose to the hands during the procedures in order to optimize the exposure to the ionizing radiation and execute the Radiological Safety Regulation (D.S. No. 009-97-Em) and the standard IR 002.2012 of radiation protection and safety in nuclear medicine. In this paper was designed and built a hand anthropomorphic phantom made of paraffin following the description given for the standard man, later were placed dosimeters ring and wrist type UD-807 model, Panasonic brand. Then we proceeded to irradiate using vial containers of Tc-99 and I-131. The obtained results showed the difference between the equivalent dose obtained among the ring and wrist dosimeter also getting a dose of 153 mSv /year when working with 99m Tc and of 61 mSv /year when working with iodine-131. Was also demonstrated that the ring dosimeter shows the average dose received in the hand with less dispersion. It was found that under the national regulation on Requirements of Radiation Protection and Nuclear Safety in Medicine article 63, indicates that higher doses of 150 mSv /year the occupationally exposed workers should have hand dosimetry. Finally the individual dose limit of 500 mSv /year in extremities can be overcome if adequate radiation protection standards do not apply. (author)

  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. 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

  7. 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

  8. 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

  9. Computational voxel phantom, associated to anthropometric and anthropomorphic real phantom for dosimetry in human male pelvis radiotherapy

    International Nuclear Information System (INIS)

    Silva, Cleuza Helena Teixeira; Campos, Tarcisio Passos Ribeiro de

    2005-01-01

    This paper addresses a computational model of voxels through MCNP5 Code and the experimental development of an anthropometric and anthropomorphic phantom for dosimetry in human male pelvis brachytherapy focusing prostatic tumors. For elaboration of the computational model of the human male pelvis, anatomical section images from the Visible Man Project were applied. Such selected and digital images were associated to a numeric representation, one for each section. Such computational representation of the anatomical sections was transformed into a bi-dimensional mesh of equivalent tissue. The group of bidimensional meshes was concatenated forming the three-dimensional model of voxels to be used by the MCNP5 code. In association to the anatomical information, data from the density and chemical composition of the basic elements, representatives of the organs and involved tissues, were setup in a material database for the MCNP-5. The model will be applied for dosimetric evaluations in situations of irradiation of the human masculine pelvis. Such 3D model of voxel is associated to the code of transport of particles MCNP5, allowing future simulations. It was also developed the construction of human masculine pelvis phantom, based on anthropometric and anthropomorphic dates and in the use of representative equivalent tissues of the skin, fatty, muscular and glandular tissue, as well as the bony structure.This part of work was developed in stages, being built the bony cast first, later the muscular structures and internal organs. They were then jointly mounted and inserted in the skin cast. The representative component of the fatty tissue was incorporate and accomplished the final retouchings in the skin. The final result represents the development of two important essential tools for elaboration of computational and experimental dosimetry. Thus, it is possible its use in calibrations of pre-existent protocols in radiotherapy, as well as for tests of new protocols, besides

  10. 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.

  11. «Anthropomorphism» as a Source of Religious Representations: in History and Nowadays

    Directory of Open Access Journals (Sweden)

    D. HORYEVOY

    2016-10-01

    Full Text Available In the present article the author discusses the varieties of the anthropomorphic theory of the origin of religion which arose at different times in different intellectual traditions. He analyzes the terminology of the concepts and provides an overview of critical opinions. The key phenomena in the theory under consideration are: anthropomorphism, animism and animatism. The article analyzes the conceptions of the philosophers Xenophanes and Feuerbach, of the British anthropologist E. B. Taylor, of the representatives of the anthropological school in Russia and of the modern cognitive science of religion.

  12. Concept development of a tendon arm manipulator and anthropomorphic robotic hand

    Science.gov (United States)

    Tolman, C. T.

    1987-01-01

    AMETEK/ORED inhouse research and development efforts leading toward a next-generation robotic manipulator arm and end-effector technology is summarized. Manipulator arm development has been directed toward a multiple-degree-of-freedom, flexible, tendon-driven concept referred to here as a Tendon Arm Manipulator (TAM). End-effector development has been directed toward a three-fingered, dextrous, tendon-driven, anthropomorphic configuration which is referred to as an Anthropomorphic Robotic Hand (ARH). Key technology issues are identified for both concepts.

  13. Beyond the Black Box: Coupling x-ray tomographic imaging of multi-phase flow processes to numerical models and traditional laboratory measurements

    DEFF Research Database (Denmark)

    Wildenschild, Dorthe; Porter, M.L.; Schaap, M.G.

    Quantitative non-invasive imaging has evolved rapidly in the last decade, and is now being used to assess a variety of problems in vadose zone research, including unsaturated flow and transport of water and contaminants, macropore-dominated processes, soil-water-root interactions, more recent work...... on colloidal processes, and significant work on NAPL-water interactions . We are now able to use non-invasive imaging to probe processes that could not previously be quantified because of lack of opacity, resolution, or accurate techniques for quantitative measurement. This work presents an overview of recent...... advances in x-ray microtomography techniques that can generate high-resolution image-based data for (1) validation of pore-scale multi-phase flow models such as the lattice-Boltzmann technique and pore network models (with respect to fluid saturations, fluid distribution, and relationships among capillary...

  14. MCPT: A Monte Carlo code for simulation of photon transport in tomographic scanners

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Gardner, R.P.; Verghese, K.

    1990-01-01

    MCPT is a special-purpose Monte Carlo code designed to simulate photon transport in tomographic scanners. Variance reduction schemes and sampling games present in MCPT were selected to characterize features common to most tomographic scanners. Combined splitting and biasing (CSB) games are used to systematically sample important detection pathways. An efficient splitting game is used to tally particle energy deposition in detection zones. The pulse height distribution of each detector can be found by convolving the calculated energy deposition distribution with the detector's resolution function. A general geometric modelling package, HERMETOR, is used to describe the geometry of the tomographic scanners and provide MCPT information needed for particle tracking. MCPT's modelling capabilites are described and preliminary experimental validation is presented. (orig.)

  15. Accuracy of the Heidelberg Spectralis in the alignment between near-infrared image and tomographic scan in a model eye: a multicenter study.

    Science.gov (United States)

    Barteselli, Giulio; Bartsch, Dirk-Uwe; Viola, Francesco; Mojana, Francesca; Pellegrini, Marco; Hartmann, Kathrin I; Benatti, Eleonora; Leicht, Simon; Ratiglia, Roberto; Staurenghi, Giovanni; Weinreb, Robert N; Freeman, William R

    2013-09-01

    To evaluate temporal changes and predictors of accuracy in the alignment between simultaneous near-infrared image and optical coherence tomography (OCT) scan on the Heidelberg Spectralis using a model eye. Laboratory investigation. After calibrating the device, 6 sites performed weekly testing of the alignment for 12 weeks using a model eye. The maximum error was compared with multiple variables to evaluate predictors of inaccurate alignment. Variables included the number of weekly scanned patients, total number of OCT scans and B-scans performed, room temperature and its variation, and working time of the scanning laser. A 4-week extension study was subsequently performed to analyze short-term changes in the alignment. The average maximum error in the alignment was 15 ± 6 μm; the greatest error was 35 μm. The error increased significantly at week 1 (P = .01), specifically after the second imaging study (P alignment were temperature variation and scans per patient (P imaging study. To improve the accuracy, room temperature should be kept stable and unnecessary scans should be avoided. The alignment of the device does not need to be checked on a regular basis in the clinical setting, but it should be checked after every other patient for more precise research purposes. Published by Elsevier Inc.

  16. Computed tomographic appearances of sternocostoclavicular hyperostosis

    Energy Technology Data Exchange (ETDEWEB)

    Chigira, Masaki; Shimizu, Toru (Gunma Univ. (Japan). Dept. of Orthopaedic Surgery)

    1989-08-01

    Computed tomographical analysis of sternocostoclavicular hyperostosis was performed in 27 patients. In the earliest stage hyperostosis occurred around the cartilaginous portion of the first ribs. The sternoclavicular joint space was preserved even in the late stage III of the disorder. It is also suggested that perichondritis and periostitis play important roles in the etiology of this disorder. (orig./GDG).

  17. Computed tomographic appearances of sternocostoclavicular hyperostosis

    International Nuclear Information System (INIS)

    Chigira, Masaki; Shimizu, Toru

    1989-01-01

    Computed tomographical analysis of sternocostoclavicular hyperostosis was performed in 27 patients. In the earliest stage hyperostosis occurred around the cartilaginous portion of the first ribs. The sternoclavicular joint space was preserved even in the late stage III of the disorder. It is also suggested that perichondritis and periostitis play important roles in the etiology of this disorder. (orig./GDG)

  18. 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...

  19. 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

  20. Case Report: Unusual computed tomographic features of ...

    African Journals Online (AJOL)

    A case report of a 57-year old woman who presented with signs and symptoms of intracranial mass. Computed tomographic (CT) and clinical features were unusual and suggestive of a parasaggital Meningioma. However an accurate diagnosis of a tuberculoma was made at surgery and histopathological examination.

  1. Quantum probability measures and tomographic probability densities

    NARCIS (Netherlands)

    Amosov, GG; Man'ko, [No Value

    2004-01-01

    Using a simple relation of the Dirac delta-function to generalized the theta-function, the relationship between the tomographic probability approach and the quantum probability measure approach with the description of quantum states is discussed. The quantum state tomogram expressed in terms of the

  2. 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

  3. 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

  4. Students' Affordance of Teleologic Explanations and Anthropomorphic Language in Eliciting Concepts in Physics

    Science.gov (United States)

    Bautista, Romiro G.

    2015-01-01

    This study ascertains that the students' affordance of teleologic explanations and anthropomorphic language in eliciting concepts in Physics is influenced by their age and learning exposure and experience. Using Explicative-Reductive Method of Descriptive Research, this study focused on the determinants of students' affordance of…

  5. Construction of a anthropomorphic phantom for dose measurement in hands in brachytherapy procedures

    International Nuclear Information System (INIS)

    Papp, Cinthia M.

    2013-01-01

    The main objective of this work was to show the differences between the dose value measured by dosimeter endpoint and the values measured in different points inside the hand during brachytherapy procedures. For this, the procedures involved in the handling of sources were analyzed and the simulated using an anthropomorphic phantom hand

  6. Who Sees Human? The Stability and Importance of Individual Differences in Anthropomorphism.

    Science.gov (United States)

    Waytz, Adam; Cacioppo, John; Epley, Nicholas

    2010-05-01

    Anthropomorphism is a far-reaching phenomenon that incorporates ideas from social psychology, cognitive psychology, developmental psychology, and the neurosciences. Although commonly considered to be a relatively universal phenomenon with only limited importance in modern industrialized societies-more cute than critical-our research suggests precisely the opposite. In particular, we provide a measure of stable individual differences in anthropomorphism that predicts three important consequences for everyday life. This research demonstrates that individual differences in anthropomorphism predict the degree of moral care and concern afforded to an agent, the amount of responsibility and trust placed on an agent, and the extent to which an agent serves as a source of social influence on the self. These consequences have implications for disciplines outside of psychology including human-computer interaction, business (marketing and finance), and law. Concluding discussion addresses how understanding anthropomorphism not only informs the burgeoning study of nonpersons, but how it informs classic issues underlying person perception as well. © The Author(s) 2010.

  7. Comparison of absorbed dose of two protocols of tomographic scanning in PET/CT exams

    International Nuclear Information System (INIS)

    Paiva, F.G.

    2017-01-01

    Positron Emission Tomography (PET) associated with Computed Tomography (CT) allows the fusion of functional and anatomical images. When compared to other diagnostic techniques, PET-CT subjects patients to higher levels of radiation, because two modalities are used in a single exam. In this study, the doses absorbed in 19 patient organs from the tomographic scan were evaluated. Radiochromic films were correctly positioned in the Alderson anthropomorphic simulator, male version. For evaluation, two whole body scan protocols were compared. For evaluation, two whole body scan protocols were compared. An increase of up to 600% in the absorbed dose in the pituitary was observed when the protocols were compared, with the lowest observed increase of approximately 160% for the liver. It is concluded that the dose from CT in patients submitted to PET-CT scanning is higher in the protocol used for diagnosis. Considering the high cost of PET-CT exam, in many cases it is preferable that the CT examination is of diagnostic quality, and not only for anatomical mapping, an argument based on the Principle of Justification

  8. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    International Nuclear Information System (INIS)

    Sommer, C. M.; Fritz, S.; Vollherbst, D.; Zelzer, S.; Wachter, M. F.; Bellemann, N.; Gockner, T.; Mokry, T.; Schmitz, A.; Aulmann, S.; Stampfl, U.; Pereira, P.; Kauczor, H. U.; Werner, J.; Radeleff, B. A.

    2015-01-01

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm 3 , and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm 3 , and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver

  9. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Fritz, S., E-mail: stefan.fritz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Vollherbst, D., E-mail: dominikvollherbst@web.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Zelzer, S., E-mail: s.zelzer@dkfz-heidelberg.de [German Cancer Research Center (dkfz), Medical and Biological Informatics (Germany); Wachter, M. F., E-mail: fredericwachter@googlemail.com; Bellemann, N., E-mail: nadine.bellemann@med.uni-heidelberg.de; Gockner, T., E-mail: theresa.gockner@med.uni-heidelberg.de; Mokry, T., E-mail: theresa.mokry@med.uni-heidelberg.de; Schmitz, A., E-mail: anne.schmitz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Aulmann, S., E-mail: sebastian.aulmann@mail.com [University Hospital Heidelberg, Department of General Pathology (Germany); Stampfl, U., E-mail: ulrike.stampfl@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P., E-mail: philippe.pereira@slk-kliniken.de [SLK Kliniken Heilbronn GmbH, Clinic for Radiology, Minimally-invasive Therapies and Nuclear Medicine (Germany); Kauczor, H. U., E-mail: hu.kauczor@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Radeleff, B. A., E-mail: boris.radeleff@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    2015-02-15

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm{sup 3}, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm{sup 3}, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

  10. Characterization of a computed tomography iterative reconstruction algorithm by image quality evaluations with an anthropomorphic phantom

    International Nuclear Information System (INIS)

    Rampado, O.; Bossi, L.; Garabello, D.; Davini, O.; Ropolo, R.

    2012-01-01

    Objective: This study aims to investigate the consequences on dose and image quality of the choices of different combinations of NI and adaptive statistical iterative reconstruction (ASIR) percentage, the image quality parameters of GE CT equipment. Methods: An anthropomorphic phantom was used to simulate the chest and upper abdomen of a standard weight patient. Images were acquired with tube current modulation and different values of noise index, in the range 10–22 for a slice thickness of 5 mm and a tube voltage of 120 kV. For each selected noise index, several image series were reconstructed using different percentages of ASIR (0, 40, 50, 60, 70, 100). Quantitative noise was assessed at different phantom locations. Computed tomography dose index (CTDI) and dose length products (DLP) were recorded. Three radiologists reviewed the images in a blinded and randomized manner and assessed the subjective image quality by comparing the image series with the one acquired with the reference protocol (noise index 14, ASIR 40%). The perceived noise, contrast, edge sharpness and overall quality were graded on a scale from −2 (much worse) to +2 (much better). Results: A repeatable trend of noise reduction versus the percentage of ASIR was observed for different noise levels and phantom locations. The different combinations of noise index and percentage of ASIR to obtain a desired dose reduction were assessed. The subjective image quality evaluation evidenced a possible dose reduction between 24 and 40% as a consequence of an increment of ASIR percentage to 50 or 70%, respectively. Conclusion: These results highlighted that the same patient dose reduction can be obtained with several combinations of noise index and percentages of ASIR, providing a model with which to choose these acquisition parameters in future optimization studies, with the aim of reducing patient dose by maintaining image quality in diagnostic levels.

  11. Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom

    Science.gov (United States)

    Jonasson, L. S.; Axelsson, J.; Riklund, K.; Boraxbekk, C. J.

    2017-07-01

    In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered-subsets maximization algorithm with spatially variant point-spread function resolution modeling provided the most accurate data. For striatum, the BP changed by 0.08% for every 1% volume change, but for smaller volumes such as the posterior caudate the artificial change in BP was as high as 0.7% per 1% volume change. A simple gross correction for striatal volume is unsatisfactory, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology, combined with the wall removal method, can be implemented to gain knowledge about the predictable bias introduced by the PVE differences in uptake regions of varying shape.

  12. Validation of dose planning calculations for boron neutron capture therapy using cylindrical and anthropomorphic phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Koivunoro, Hanna; Seppaelae, Tiina; Uusi-Simola, Jouni; Merimaa, Katja; Savolainen, Sauli [Department of Physics, POB 64, FI-00014 University of Helsinki (Finland); Kotiluoto, Petri; Seren, Tom; Auterinen, Iiro [VTT Technical Research Centre of Finland, Espoo, POB 1000, FI-02044 VTT (Finland); Kortesniemi, Mika, E-mail: hanna.koivunoro@helsinki.f [HUS Helsinki Medical Imaging Center, University of Helsinki, POB 340, FI-00029 HUS (Finland)

    2010-06-21

    In this paper, the accuracy of dose planning calculations for boron neutron capture therapy (BNCT) of brain and head and neck cancer was studied at the FiR 1 epithermal neutron beam. A cylindrical water phantom and an anthropomorphic head phantom were applied with two beam aperture-to-surface distances (ASD). The calculations using the simulation environment for radiation application (SERA) treatment planning system were compared to neutron activation measurements with Au and Mn foils, photon dose measurements with an ionization chamber and the reference simulations with the MCNP5 code. Photon dose calculations using SERA differ from the ionization chamber measurements by 2-13% (disagreement increased along the depth in the phantom), but are in agreement with the MCNP5 calculations within 2%. The {sup 55}Mn(n,{gamma}) and {sup 197}Au(n,{gamma}) reaction rates calculated using SERA agree within 10% and 8%, respectively, with the measurements and within 5% with the MCNP5 calculations at depths >0.5 cm from the phantom surface. The {sup 55}Mn(n,{gamma}) reaction rate represents the nitrogen and boron depth dose within 1%. Discrepancy in the SERA fast neutron dose calculation (of up to 37%) is corrected if the biased fast neutron dose calculation option is not applied. Reduced voxel cell size ({<=}0.5 cm) improves the SERA calculation accuracy on the phantom surface. Despite the slight overestimation of the epithermal neutrons and underestimation of the thermal neutrons in the beam model, neutron calculation accuracy with the SERA system is sufficient for reliable BNCT treatment planning with the two studied treatment distances. The discrepancy between measured and calculated photon dose remains unsatisfactorily high for depths >6 cm from the phantom surface. Increasing discrepancy along the phantom depth is expected to be caused by the inaccurately determined effective point of the ionization chamber.

  13. Characterization of a computed tomography iterative reconstruction algorithm by image quality evaluations with an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Rampado, O., E-mail: orampado@molinette.piemonte.it [S.C. Fisica Sanitaria, San Giovanni Battista Hospital of Turin, Corso Bramante 88, Torino 10126 (Italy); Bossi, L., E-mail: laura-bossi@hotmail.it [S.C. Fisica Sanitaria, San Giovanni Battista Hospital of Turin, Corso Bramante 88, Torino 10126 (Italy); Garabello, D., E-mail: dgarabello@molinette.piemonte.it [S.C. Radiodiagnostica DEA, San Giovanni Battista Hospital of Turin, Corso Bramante 88, Torino 10126 (Italy); Davini, O., E-mail: odavini@molinette.piemonte.it [S.C. Radiodiagnostica DEA, San Giovanni Battista Hospital of Turin, Corso Bramante 88, Torino 10126 (Italy); Ropolo, R., E-mail: rropolo@molinette.piemonte.it [S.C. Fisica Sanitaria, San Giovanni Battista Hospital of Turin, Corso Bramante 88, Torino 10126 (Italy)

    2012-11-15

    Objective: This study aims to investigate the consequences on dose and image quality of the choices of different combinations of NI and adaptive statistical iterative reconstruction (ASIR) percentage, the image quality parameters of GE CT equipment. Methods: An anthropomorphic phantom was used to simulate the chest and upper abdomen of a standard weight patient. Images were acquired with tube current modulation and different values of noise index, in the range 10-22 for a slice thickness of 5 mm and a tube voltage of 120 kV. For each selected noise index, several image series were reconstructed using different percentages of ASIR (0, 40, 50, 60, 70, 100). Quantitative noise was assessed at different phantom locations. Computed tomography dose index (CTDI) and dose length products (DLP) were recorded. Three radiologists reviewed the images in a blinded and randomized manner and assessed the subjective image quality by comparing the image series with the one acquired with the reference protocol (noise index 14, ASIR 40%). The perceived noise, contrast, edge sharpness and overall quality were graded on a scale from -2 (much worse) to +2 (much better). Results: A repeatable trend of noise reduction versus the percentage of ASIR was observed for different noise levels and phantom locations. The different combinations of noise index and percentage of ASIR to obtain a desired dose reduction were assessed. The subjective image quality evaluation evidenced a possible dose reduction between 24 and 40% as a consequence of an increment of ASIR percentage to 50 or 70%, respectively. Conclusion: These results highlighted that the same patient dose reduction can be obtained with several combinations of noise index and percentages of ASIR, providing a model with which to choose these acquisition parameters in future optimization studies, with the aim of reducing patient dose by maintaining image quality in diagnostic levels.

  14. 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

  15. The computed tomographic appearances of cherubism

    International Nuclear Information System (INIS)

    Bianchi, S.D.; Boccardi, A.; Mela, F.; Romagnoli, R.

    1987-01-01

    The computed tomographic (CT) aspects of six cases of cherubism are described. Through its optimal representation of the lesions, CT enabled certain characteristics of this disease to be substantiated, namely, limitation of the process to the bones of the jaw and primarily superficial development of the mandibular lesions, coupled with an unusual mandibular condylar impairment. Moreover, the composition of this series permitted investigation of the condition in its several stages of progression. (orig.)

  16. Tomographic scanning apparatus with ionization detector means

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification describes a tomographic scanning apparatus using a fan beam and digital output signal. Particular reference is made to the gas-pressurized ionization detector chamber, consisting of an array of side-by-side elongate ionization detection cells, the principal axis of each of the said cells being oriented along a radius extending towards the radiation source, and connection means for applying potentials across the cells for taking their output signals. (U.K.)

  17. 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.

  18. NOTE: On the need to revise the arm structure in stylized anthropomorphic phantoms in lateral photon irradiation geometry

    Science.gov (United States)

    Lee, Choonsik; Lee, Choonik; Lee, Jai-Ki

    2006-11-01

    Distributions of radiation absorbed dose within human anatomy have been estimated through Monte Carlo radiation transport techniques implemented for two different classes of computational anthropomorphic phantoms: (1) mathematical equation-based stylized phantoms and (2) tomographic image-based voxel phantoms. Voxel phantoms constructed from tomographic images of real human anatomy have been actively developed since the late 1980s to overcome the anatomical approximations necessary with stylized phantoms, which themselves have been utilized since the mid 1960s. However, revisions of stylized phantoms have also been pursued in parallel to the development of voxel phantoms since voxel phantoms (1) are initially restricted to the individual-specific anatomy of the person originally imaged, (2) must be restructured on an organ-by-organ basis to conform to reference individual anatomy and (3) cannot easily represent very fine anatomical structures and tissue layers that are thinner than the voxel dimensions of the overall phantom. Although efforts have been made to improve the anatomic realism of stylized phantoms, most of these efforts have been limited to attempts to alter internal organ structures. Aside from the internal organs, the exterior shapes, and especially the arm structures, of stylized phantoms are also far from realistic descriptions of human anatomy, and may cause dosimetry errors in the calculation of organ-absorbed doses for external irradiation scenarios. The present study was intended to highlight the need to revise the existing arm structure within stylized phantoms by comparing organ doses of stylized adult phantoms with those from three adult voxel phantoms in the lateral photon irradiation geometry. The representative stylized phantom, the adult phantom of the Oak Ridge National Laboratory (ORNL) series and two adult male voxel phantoms, KTMAN-2 and VOXTISS8, were employed for Monte Carlo dose calculation, and data from another voxel phantom, VIP

  19. On the need to revise the arm structure in stylized anthropomorphic phantoms in lateral photon irradiation geometry

    International Nuclear Information System (INIS)

    Lee, Choonsik; Lee, Choonik; Lee, Jai-Ki

    2006-01-01

    Distributions of radiation absorbed dose within human anatomy have been estimated through Monte Carlo radiation transport techniques implemented for two different classes of computational anthropomorphic phantoms: (1) mathematical equation-based stylized phantoms and (2) tomographic image-based voxel phantoms. Voxel phantoms constructed from tomographic images of real human anatomy have been actively developed since the late 1980s to overcome the anatomical approximations necessary with stylized phantoms, which themselves have been utilized since the mid 1960s. However, revisions of stylized phantoms have also been pursued in parallel to the development of voxel phantoms since voxel phantoms (1) are initially restricted to the individual-specific anatomy of the person originally imaged, (2) must be restructured on an organ-by-organ basis to conform to reference individual anatomy and (3) cannot easily represent very fine anatomical structures and tissue layers that are thinner than the voxel dimensions of the overall phantom. Although efforts have been made to improve the anatomic realism of stylized phantoms, most of these efforts have been limited to attempts to alter internal organ structures. Aside from the internal organs, the exterior shapes, and especially the arm structures, of stylized phantoms are also far from realistic descriptions of human anatomy, and may cause dosimetry errors in the calculation of organ-absorbed doses for external irradiation scenarios. The present study was intended to highlight the need to revise the existing arm structure within stylized phantoms by comparing organ doses of stylized adult phantoms with those from three adult voxel phantoms in the lateral photon irradiation geometry. The representative stylized phantom, the adult phantom of the Oak Ridge National Laboratory (ORNL) series and two adult male voxel phantoms, KTMAN-2 and VOXTISS8, were employed for Monte Carlo dose calculation, and data from another voxel phantom, VIP

  20. 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

  1. TU-F-CAMPUS-I-02: Validation of a CT X-Ray Source Characterization Technique for Dose Computation Using An Anthropomorphic Thorax Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Sommerville, M; Tambasco, M [San Diego State University, San Diego, CA (United States); Poirier, Y [CancerCare Manitoba, Winnipeg, MB (Canada)

    2015-06-15

    Purpose: To experimentally validate a rotational kV x-ray source characterization technique by computing CT dose in an anthropomorphic thorax phantom using an in-house dose computation algorithm (kVDoseCalc). Methods: The lateral variation in incident energy spectra of a GE Optima big bore CT scanner was found by measuring the HVL along the internal, full bow-tie filter axis. The HVL and kVp were used to generate the x-ray spectra using Spektr software, while beam fluence was derived by dividing the integral product of the spectra and in-air mass-energy absorption coefficients by in-air dose measurements along the bow-tie filter axis. Beams produced by the GE Optima scanner were modeled at 80 and 140 kVp tube settings. kVDoseCalc calculates dose by solving the linear Boltzmann transport equation using a combination of deterministic and stochastic methods. Relative doses in an anthropomorphic thorax phantom (E2E SBRT Phantom) irradiated by the GE Optima scanner were measured using a (0.015 cc) PTW Freiburg ionization chamber, and compared to computations from kVDoseCalc. Results: The agreement in relative dose between dose computation and measurement for points of interest (POIs) within the primary path of the beam was within experimental uncertainty for both energies, however points outside the primary beam were not. The average absolute percent difference for POIs within the primary path of the beam was 1.37% and 5.16% for 80 and 140 kVp, respectively. The minimum and maximum absolute percent difference for both energies and all POIs within the primary path of the beam was 0.151% and 6.41%, respectively. Conclusion: The CT x-ray source characterization technique based on HVL measurements and kVp can be used to accurately compute CT dose in an anthropomorphic thorax phantom.

  2. Mechanical design and performance specifications of anthropomorphic prosthetic hands: a review.

    Science.gov (United States)

    Belter, Joseph T; Segil, Jacob L; Dollar, Aaron M; Weir, Richard F

    2013-01-01

    In this article, we set forth a detailed analysis of the mechanical characteristics of anthropomorphic prosthetic hands. We report on an empirical study concerning the performance of several commercially available myoelectric prosthetic hands, including the Vincent, iLimb, iLimb Pulse, Bebionic, Bebionic v2, and Michelangelo hands. We investigated the finger design and kinematics, mechanical joint coupling, and actuation methods of these commercial prosthetic hands. The empirical findings are supplemented with a compilation of published data on both commercial and prototype research prosthetic hands. We discuss numerous mechanical design parameters by referencing examples in the literature. Crucial design trade-offs are highlighted, including number of actuators and hand complexity, hand weight, and grasp force. Finally, we offer a set of rules of thumb regarding the mechanical design of anthropomorphic prosthetic hands.

  3. The Role of Anthropomorphic Phantoms in Diagnostic Ultrasound Imaging for Disease Characterization (abstract)

    Science.gov (United States)

    Cannon, L. M.; King, D. M.; Browne, J. E.

    2009-04-01

    An anthropomorhic phantom is an object that can mimic a region of the human anatomy. Anthropomorphic phantoms have a variety of roles in diagnostic ultrasound. These roles include quality assurance testing of ultrasound machines, calibration and testing of new imaging techniques, training of sonographers, and-most importantly-use as a tool to obtain a better understanding of disease progression in the relevant anatomy. To be anthropomorphic a phantom must accurately mimic the body in terms of its ultrasonic and mechanical properties, as well as anatomically. The acoustic properties are speed of sound, attenuation, and backscatter. The mechanical properties are elasticity and density. Phantoms are constructed from tissue-mimicking materials (TMMs). TMMs are prepared from a variety of ingredients, such as gelatine, agar, safflower oil, and glass beads. These ingredients are then boiled and cooled under controlled conditions to produce a solid TMM. To determine if the TMM has the correct acoustic properties, acoustic measurements are performed using a scanning acoustic macroscope. Mechanical measurements are also performed to test the elasticity and density properties. TMMs with the correct properties are subsequently put through a series of moulding procedures to produce the anthropomorphic phantom.

  4. Characterisation of an anthropomorphic chest phantom for dose measurements in radiology beams

    Science.gov (United States)

    Henriques, L. M. S.; Cerqueira, R. A. D.; Santos, W. S.; Pereira, A. J. S.; Rodrigues, T. M. A.; Carvalho Júnior, A. B.; Maia, A. F.

    2014-02-01

    The objective of this study was to characterise an anthropomorphic chest phantom for dosimetric measurements of conventional radiology beams. This phantom was developed by a previous research project at the Federal University of Sergipe for image quality control tests. As the phantom consists of tissue-equivalent material, it is possible to characterise it for dosimetric studies. For comparison, a geometric chest phantom, consisting of PMMA (polymethylmethacrylate) with dimensions of 30×30×15 cm³ was used. Measurements of incident air kerma (Ki) and entrance surface dose (ESD) were performed using ionisation chambers. From the results, backscatter factors (BSFs) of the two phantoms were determined and compared with values estimated by CALDose_X software, based on a Monte Carlo simulation. For the technical parameters evaluated in this study, the ESD and BSF values obtained experimentally showed a good similarity between the two phantoms, with minimum and maximum difference of 0.2% and 7.0%, respectively, and showed good agreement with the results published in the literature. Organ doses and effective doses for the anthropomorphic phantom were also estimated by the determination of conversion coefficients (CCs) using the visual Monte Carlo (VMC) code. Therefore, the results of this study prove that the anthropomorphic thorax phantom proposed is a good tool to use in dosimetry and can be used for risk evaluation of X-ray diagnostic procedures.

  5. The Role of Anthropomorphic Phantoms in Diagnostic Ultrasound Imaging for Disease Characterization

    International Nuclear Information System (INIS)

    Cannon, L. M.; King, D. M.; Browne, J. E.

    2009-01-01

    An anthropomorhic phantom is an object that can mimic a region of the human anatomy. Anthropomorphic phantoms have a variety of roles in diagnostic ultrasound. These roles include quality assurance testing of ultrasound machines, calibration and testing of new imaging techniques, training of sonographers, and--most importantly--use as a tool to obtain a better understanding of disease progression in the relevant anatomy. To be anthropomorphic a phantom must accurately mimic the body in terms of its ultrasonic and mechanical properties, as well as anatomically. The acoustic properties are speed of sound, attenuation, and backscatter. The mechanical properties are elasticity and density. Phantoms are constructed from tissue-mimicking materials (TMMs). TMMs are prepared from a variety of ingredients, such as gelatine, agar, safflower oil, and glass beads. These ingredients are then boiled and cooled under controlled conditions to produce a solid TMM. To determine if the TMM has the correct acoustic properties, acoustic measurements are performed using a scanning acoustic macroscope. Mechanical measurements are also performed to test the elasticity and density properties. TMMs with the correct properties are subsequently put through a series of moulding procedures to produce the anthropomorphic phantom.

  6. Performance of an automatic dose control system for CT. Anthropomorphic phantom studies

    Energy Technology Data Exchange (ETDEWEB)

    Gosch, D.; Stumpp, P.; Kahn, T. [Universitaetsklinikum Leipzig (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie; Nagel, H.D. [Wissenschaft und Technik fuer die Radiologie, Dr. HD Nagel, Buchholz (Germany)

    2011-02-15

    Purpose: To assess the performance and to provide more detailed insight into characteristics and limitations of devices for automatic dose control (ADC) in CT. Materials and Methods: A comprehensive study on DoseRight 2.0, the ADC system provided by Philips for its Brilliance CT scanners, was conducted with assorted tests using an anthropomorphic phantom that allowed simulation of the operation of the system under almost realistic conditions. The scan protocol settings for the neck, chest and abdomen with pelvis were identical to those applied in the clinical routine. Results: Using the appropriate ADC functionalities, dose reductions equal 40 % for the neck, 20 % for the chest and 10 % for the abdomen with pelvis. Larger dose reductions can be expected for average patients, since their attenuating properties differ significantly from the anthropomorphic phantom. Adverse effects due to increased image noise were only moderate as a consequence of the 'adequate noise system' design and the complementary use of adaptive filtration. The results of specific tests also provided deeper insight into the operation of the ADC system that helps to identify the causes of suspected malfunctions and to prevent potential pitfalls. Conclusion: Tests with anthropomorphic phantoms allow verification of the characteristics of devices for ADC in CT under almost realistic conditions. However, differences in phantom shape and material composition require supplementary patient studies on representative patient groups. (orig.)

  7. Computed tomographic findings of traumatic intracranial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Seong Wook; Kim, Il Young; Lee, Byung Ho; Kim, Ki Jeoung; Yoon, Il Gyu [Soonchunhyang University College of Medicine, Seoul (Korea, Republic of)

    1985-10-15

    Traumatic intracranial lesion has been one of the most frequent and serious problem in neurosurgical pathology. Computed tomography made it possible to get prompt diagnosis and surgical intervention of intracranial lesions by its safety, fastness and accuracy. Computed tomographic scan was carried out on 1309 cases at Soonchunhyang Chunan Hospital for 15 months from October 1983 to December 1984. We have reviewed the computed tomographic scans of 264 patients which showed traumatic intracranial lesion. The result were as follows: 1. Head trauma was the most frequent diagnosed disease using computed tomographic scans (57.8%) and among 264 cases the most frequent mode of injury was traffic accident (73.9%). 2. Skull fracture was accompanied in frequency of 69.7% and it was detected in CT in 38.6%: depression fracture was more easily detected in 81%. 3. Conutercoup lesion (9.5%) was usually accompanied with temporal and occipital fracture, and it appeared in lower incidence among pediatric group. 4. Intracranial lesions of all 264 cases were generalized cerebral swelling (24.6%), subdural hematoma (22.3%), epidural hematoma (20.8%), intracerebral hematoma (6.1%), and subarachnoid hemorrhage (3.0%). 5. The shape of hematoma was usually biconvex (92.7%) in acute epidural hematoma and cresentic (100%) in acute subdural hematoma, but the most chronic the case became, they showed planoconvex and bicconvex shapes. 6. Extra-axial hematoma was getting decreased in density as time gone by. 7. Hematoma density was not in direct proportion to serum hemoglobin level as single factor.

  8. Computed tomographic findings of traumatic intracranial lesions

    International Nuclear Information System (INIS)

    Jeong, Seong Wook; Kim, Il Young; Lee, Byung Ho; Kim, Ki Jeoung; Yoon, Il Gyu

    1985-01-01

    Traumatic intracranial lesion has been one of the most frequent and serious problem in neurosurgical pathology. Computed tomography made it possible to get prompt diagnosis and surgical intervention of intracranial lesions by its safety, fastness and accuracy. Computed tomographic scan was carried out on 1309 cases at Soonchunhyang Chunan Hospital for 15 months from October 1983 to December 1984. We have reviewed the computed tomographic scans of 264 patients which showed traumatic intracranial lesion. The result were as follows: 1. Head trauma was the most frequent diagnosed disease using computed tomographic scans (57.8%) and among 264 cases the most frequent mode of injury was traffic accident (73.9%). 2. Skull fracture was accompanied in frequency of 69.7% and it was detected in CT in 38.6%: depression fracture was more easily detected in 81%. 3. Conutercoup lesion (9.5%) was usually accompanied with temporal and occipital fracture, and it appeared in lower incidence among pediatric group. 4. Intracranial lesions of all 264 cases were generalized cerebral swelling (24.6%), subdural hematoma (22.3%), epidural hematoma (20.8%), intracerebral hematoma (6.1%), and subarachnoid hemorrhage (3.0%). 5. The shape of hematoma was usually biconvex (92.7%) in acute epidural hematoma and cresentic (100%) in acute subdural hematoma, but the most chronic the case became, they showed planoconvex and bicconvex shapes. 6. Extra-axial hematoma was getting decreased in density as time gone by. 7. Hematoma density was not in direct proportion to serum hemoglobin level as single factor

  9. Computerized tomographic diagnosis of basal skull fracture

    International Nuclear Information System (INIS)

    Tanaka, Tokutaro; Shimoyama, Ichiro; Endoh, Mitsutoshi; Ninchoji, Toshiaki; Uemura, Kenichi.

    1984-01-01

    The diagnosis of basal skull fractures used to be difficult, particularly on the basis of routine skull roentgenography alone. We have now examined the diagnostic value of conventional computerized tomography in basal skull fractures. We studied 82 cases clinically diagnosed as basal skull fractures. We examined them based on at least one of the following computerized tomographic criteria for basal skull fractures: 1) fracture line(s), 2) intracranial air, 3) fluid in the paranasal sinuses, and 4) fluid in the middle ear, including the mastoid air cells. The signs of the fracture line and of the intracranial air are definite indications of basal skull fracture, but the signs of fluid in the paranasal sinuses and/or in the middle ear are not definite. When combined, however, with such other clinical signs as black eye, Battle's sign, CSF leakage, CSF findings, and profuse nasal or ear bleeding, the diagnosis is more reliable. Seventy cases (85.4%) in this series had basal skull fractures according to our computerized tomographic criteria. Among them , 26 cases (31.7%) were diagnosed with fracture lines, 17 cases (20.7%) with intracranial air, 16 cases (19.5%) with fluid in the paranasal sinuses, 10 cases (12.2%) with fluid in the middle ear, and one case (1.2%) with fluid in both. Twelve cases (14.6%) of the 82 cases clinically diagnosed as basal skull fractures could not have been diagnosed on our computerized tomographic criteria alone. We diagnosed them because of CSF leakage, CSF findings, surgical findings, etc. (author)

  10. Computer tomographic investigation of ancient Egyptian mummies

    International Nuclear Information System (INIS)

    Huebner, K.H.; Pahl, W.M.; Tuebingen Univ.

    1981-01-01

    Radiological and computer tomographic examinations of Egyptian mummies have been carried out at the Institute of Anthropology and Human Genetics from 1975 to 1978. These have demonstrated the value of CT in medical archaeology. It enables one to study the soft tissues, the skin (if bandaged), the muscles and any organs retained in situ for magical or religious reason. Measurements of attenuation values indicate the materials which were used for mummifying the skin and organs. Characteristic examples are described and the early results of these examinations are discussed. (orig.) [de

  11. Computer tomographic investigation of ancient Egyptian mummies

    Energy Technology Data Exchange (ETDEWEB)

    Huebner, K H; Pahl, W M

    1981-08-01

    Radiological and computer tomographic examinations of Egyptian mummies have been carried out at the Institute of Anthropology and Human Genetics from 1975 to 1978. These have demonstrated the value of CT in medical archaeology. It enables one to study the soft tissues, the skin (if bandaged), the muscles and any organs retained in situ for magical or religious reason. Measurements of attenuation values indicate the materials which were used for mummifying the skin and organs. Characteristic examples are described and the early results of these examinations are discussed.

  12. An intragastric trichobezoar: computerised tomographic appearance.

    Directory of Open Access Journals (Sweden)

    Morris B

    2000-04-01

    Full Text Available A 26-year-old lady presented with a history of abdominal pain and distension since two months. The ultrasound examination showed an epigastric mass, which was delineated as a filling defect in the stomach on barium studies. The computerised tomographic scan showed a gastric mass with pockets of air in it, without post-contrast enhancement. This case highlights the characteristic appearance on computerised tomography of a bezoar within the stomach, a feature that is not commonly described in medical literature.

  13. Computed tomographic study in children with microcephaly

    International Nuclear Information System (INIS)

    Ito, Masatoshi; Okuno, Takehiko; Mikawa, Haruki

    1989-01-01

    Computed tomographic (CT) brain scanning was performed on fifty-eight infants and children with microcephaly. CT scans were useful for detecting unsuspected brain lesions and for diagnosing underlying diseases. The head size did not correlate with the CT findings, the degree of mental retardation, or the existence of motor disturbance or epilepsy. On the other hand, the CT findings were correlated with the degree of mental retardation, and the existence of motor disturbance or epilepsy. CT scans were useful for determining the prognosis of the microcephaly. (author)

  14. The use of tomographic techniques in the mineral processing Industry. A review

    International Nuclear Information System (INIS)

    Witika, L.K.; Jere, E.H.

    2002-01-01

    Process tomographic techniques may be used to analyse the internal state of most of the multiphase process engineering systems such as material segregation in a reactor multiphase flow in pipes and the spatial resolution of mineral grains in multiphase particles. These techniques include radiation computed tomography (X-ray or ray), electrical methods(capacitance, impedance and inductive tomography) positron emission tomography,optical tomography, microwave tomography, acoustic tomographical methods and many more. Many potential applications exist for process tomographic instrumentation for quantitative analysis and fault-detection purposes. Amongst these, electrical methods are widely used for those mineral processes deserving particular attention such as dense-medium separation, hydro cyclones, flotation cells and columns, gas-liquid absorbers, solvent extraction and other liquid-liquid processes, filtration and other solid-liquid processes, grinding mills (both dry and wet, conveyors and hoppers). Development in on-line measurement instrumentation now allow direct observation of the behaviour of fluids inside mineral separation equipment. This offers the possibility to acquire process data to enable models to be devised, to verify theoretical computational fluid dynamics predictions and control of various unit processes. In this review, the most important tomographic sensing methods are reviewed. Examples of the implementation of some electrical methods are illustrated. (authors)

  15. 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.

  16. SU-E-I-94: Automated Image Quality Assessment of Radiographic Systems Using An Anthropomorphic Phantom

    International Nuclear Information System (INIS)

    Wells, J; Wilson, J; Zhang, Y; Samei, E; Ravin, Carl E.

    2014-01-01

    Purpose: In a large, academic medical center, consistent radiographic imaging performance is difficult to routinely monitor and maintain, especially for a fleet consisting of multiple vendors, models, software versions, and numerous imaging protocols. Thus, an automated image quality control methodology has been implemented using routine image quality assessment with a physical, stylized anthropomorphic chest phantom. Methods: The “Duke” Phantom (Digital Phantom 07-646, Supertech, Elkhart, IN) was imaged twice on each of 13 radiographic units from a variety of vendors at 13 primary care clinics. The first acquisition used the clinical PA chest protocol to acquire the post-processed “FOR PRESENTATION” image. The second image was acquired without an antiscatter grid followed by collection of the “FOR PROCESSING” image. Manual CNR measurements were made from the largest and thickest contrast-detail inserts in the lung, heart, and abdominal regions of the phantom in each image. An automated image registration algorithm was used to estimate the CNR of the same insert using similar ROIs. Automated measurements were then compared to the manual measurements. Results: Automatic and manual CNR measurements obtained from “FOR PRESENTATION” images had average percent differences of 0.42%±5.18%, −3.44%±4.85%, and 1.04%±3.15% in the lung, heart, and abdominal regions, respectively; measurements obtained from “FOR PROCESSING” images had average percent differences of -0.63%±6.66%, −0.97%±3.92%, and −0.53%±4.18%, respectively. The maximum absolute difference in CNR was 15.78%, 10.89%, and 8.73% in the respective regions. In addition to CNR assessment of the largest and thickest contrast-detail inserts, the automated method also provided CNR estimates for all 75 contrast-detail inserts in each phantom image. Conclusion: Automated analysis of a radiographic phantom has been shown to be a fast, robust, and objective means for assessing radiographic

  17. A method to acquire CT organ dose map using OSL dosimeters and ATOM anthropomorphic phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Da; Li, Xinhua; Liu, Bob [Division of Diagnostic Imaging Physics and Webster Center for Advanced Research and Education in Radiation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Gao, Yiming; Xu, X. George [Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2013-08-15

    Purpose: To present the design and procedure of an experimental method for acquiring densely sampled organ dose map for CT applications, based on optically stimulated luminescence (OSL) dosimeters “nanoDots” and standard ATOM anthropomorphic phantoms; and to provide the results of applying the method—a dose data set with good statistics for the comparison with Monte Carlo simulation result in the future.Methods: A standard ATOM phantom has densely located holes (in 3 × 3 cm or 1.5 × 1.5 cm grids), which are too small (5 mm in diameter) to host many types of dosimeters, including the nanoDots. The authors modified the conventional way in which nanoDots are used, by removing the OSL disks from the holders before inserting them inside a standard ATOM phantom for dose measurements. The authors solved three technical difficulties introduced by this modification: (1) energy dependent dose calibration for raw OSL readings; (2) influence of the brief background exposure of OSL disks to dimmed room light; (3) correct pairing between the dose readings and measurement locations. The authors acquired 100 dose measurements at various positions in the phantom, which was scanned using a clinical chest protocol with both angular and z-axis tube current modulations.Results: Dose calibration was performed according to the beam qualities inside the phantom as determined from an established Monte Carlo model of the scanner. The influence of the brief exposure to dimmed room light was evaluated and deemed negligible. Pairing between the OSL readings and measurement locations was ensured by the experimental design. The organ doses measured for a routine adult chest scan protocol ranged from 9.4 to 18.8 mGy, depending on the composition, location, and surrounding anatomy of the organs. The dose distribution across different slices of the phantom strongly depended on the z-axis mA modulation. In the same slice, doses to the soft tissues other than the spinal cord demonstrated

  18. A method to acquire CT organ dose map using OSL dosimeters and ATOM anthropomorphic phantoms

    International Nuclear Information System (INIS)

    Zhang, Da; Li, Xinhua; Liu, Bob; Gao, Yiming; Xu, X. George

    2013-01-01

    Purpose: To present the design and procedure of an experimental method for acquiring densely sampled organ dose map for CT applications, based on optically stimulated luminescence (OSL) dosimeters “nanoDots” and standard ATOM anthropomorphic phantoms; and to provide the results of applying the method—a dose data set with good statistics for the comparison with Monte Carlo simulation result in the future.Methods: A standard ATOM phantom has densely located holes (in 3 × 3 cm or 1.5 × 1.5 cm grids), which are too small (5 mm in diameter) to host many types of dosimeters, including the nanoDots. The authors modified the conventional way in which nanoDots are used, by removing the OSL disks from the holders before inserting them inside a standard ATOM phantom for dose measurements. The authors solved three technical difficulties introduced by this modification: (1) energy dependent dose calibration for raw OSL readings; (2) influence of the brief background exposure of OSL disks to dimmed room light; (3) correct pairing between the dose readings and measurement locations. The authors acquired 100 dose measurements at various positions in the phantom, which was scanned using a clinical chest protocol with both angular and z-axis tube current modulations.Results: Dose calibration was performed according to the beam qualities inside the phantom as determined from an established Monte Carlo model of the scanner. The influence of the brief exposure to dimmed room light was evaluated and deemed negligible. Pairing between the OSL readings and measurement locations was ensured by the experimental design. The organ doses measured for a routine adult chest scan protocol ranged from 9.4 to 18.8 mGy, depending on the composition, location, and surrounding anatomy of the organs. The dose distribution across different slices of the phantom strongly depended on the z-axis mA modulation. In the same slice, doses to the soft tissues other than the spinal cord demonstrated

  19. 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.

  20. 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.

  1. 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)

  2. Dynamics of Anthropomorphic Painting Robot: Quality Analysis and Cost Reduction

    NARCIS (Netherlands)

    Potkonjak, V.; Djordjevic, G.; Kostic, D.; Rasic, M.

    2000-01-01

    Application of robots in spray-painting tasks results in low-cost production, persistent quality and protects humans from a hostile working environment. Automated planning of applicator’s trajectory requires a model of paint deposition onto the treated surface and formulation of an appropriate

  3. Construction of cardiac anthropomorphic phantom for simulation of radiological exams; Construção de fantoma antropomórfico cardíaco para simulação de exames radiológicos

    Energy Technology Data Exchange (ETDEWEB)

    Bandeira, C.K.; Vieira Neto, H., E-mail: cbandeira@alunos.utfpr.edu.br, E-mail: hvieir@utfpr.edu.br [Universidade Tecnológica Federal do Paraná (UTFPR), Curitiba (Brazil). Programa de Pós-Graduação em Engenharia Elétrica e Informática Industrial; Vieira, M.P.M.M., E-mail: michele.vieira@ifpr.edu.br [Instituto Federal do Paraná (IFPR), Curitiba, PR (Brazil). Curso Técnico em Radiologia

    2017-07-01

    Phantoms are simulating objects of structures of the human body and can be applied in the quality control and calibration of radiological equipment. The aim of the work is the development of a cardiac anthropomorphic phantom to assist in the elaboration of protocols of dynamic studies that demonstrate the blood circulation inside the cardiac chambers. For the construction of the phantom was used latex, applied in layers on an anatomical model of heart, having been constructed the cardiac chambers and atrioventricular valves. Cardiac chambers were connected to the cannulas for fluid injection and simulation of the circulatory system. The constructed phantom presents anthropomorphic characteristics and allows the circulation of the fluid without reflux, but the thickness of the catheters used does not yet allow flows of greater order of magnitude. This phantom has the potential to be used in the dynamic simulation of cardiac exams, contributing to the elaboration and adequacy of computed tomography protocols.

  4. X-ray Tomographic Microscopy at TOMCAT

    Energy Technology Data Exchange (ETDEWEB)

    Marone, F; Hintermueller, C; McDonald, S; Abela, R; Mikuljan, G; Isenegger, A; Stampanoni, M, E-mail: federica.marone@psi.c [Swiss Light Source, Paul Scherrer Institut, 5232 Villigen (Switzerland)

    2009-09-01

    Synchrotron-based X-ray Tomographic Microscopy is a powerful technique for fast non-destructive, high resolution quantitative volumetric investigations on diverse samples. At the TOMCAT (TOmographic Microscopy and Coherent rAdiology experimenTs) beamline at the Swiss Light Source, synchrotron light is delivered by a 2.9 T superbend. The main optical component, a Double Crystal Multilayer Monochromator, covers an energy range between 8 and 45 keV. The standard TOMCAT detector offers field of views ranging from 0.75x0.75 mm{sup 2} up to 12.1x12.1 mm{sup 2} with a pixel size of 0.37 {mu}m and 5.92 {mu}m, respectively. In addition to routine measurements, which exploit the absorption contrast, the high coherence of the source also enables phase contrast tomography, implemented with two complementary techniques (Modified Transport of Intensity approach and Grating Interferometry). Typical acquisition times for a tomogram are in the order of few minutes, ensuring high throughput and allowing for semi-dynamical investigations. Raw data are automatically post-processed online and full reconstructed volumes are available shortly after a scan with minimal user intervention.

  5. 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

  6. 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

  7. Bone densitometry with the computer tomograph

    International Nuclear Information System (INIS)

    Weiss, T.

    1978-01-01

    This work tests the usefulness of the EMI head scanner MARK I for a quantitative detection of ossary mineral content. Twenty-three concentration levels of a aqueous K 2 HPO 4 -solution were positioned by means of a special clamping device at the EMI-scanner and examined at tubevoltages of 100, 120 and 140 kV. This produces an almost linear dependence between CT-unit and sample concentration, whereby it shows that the measured special element densities of samples with the same densities vary in dependence with the voltage. The examination of an anotomical fore-arm preperate served as a statement for the reproductability of computer tomographic densitometry at non-moving biological objects. The test of reproductability of bone densitometry measurements under clinical conditions was made on the occation of the six time examinations of the right hand fore-arm bone of a young dummy. Furthermore densitometric examination were made at the fore-arm shelton of 40 long-time dialysis patients in the age levels between 17 and 67 years. The reproductability of the technique presented here is at least not better with the EMI-head-scanner MARK I used here. A change is possible by using the new whole body tomographs. (orig./MG) [de

  8. BIOMIMETIC ACTUATION OF NON-ANTHROPOMORPHIC GRIPPER SYSTEMS

    Directory of Open Access Journals (Sweden)

    Tudor DEACONESCU

    2015-05-01

    Full Text Available The paper presents the stages of developing new, light, eco-friendly and bionic gripper systems. Gripping is achieved by means of original, self-adaptive, bio-inspired systems, with a pneumatic muscle as motion generator. The method underlying the development of these new gripping systems is based on the creation of concepts by analogy, an instrument aimed at widening the inspiration horizon in designing by using models from nature.

  9. 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.

  10. Positioning of the detectors inside an anthropomorphic phantom in order to measure the effective dose at workplace

    International Nuclear Information System (INIS)

    Furstoss, C.; Menard, S.

    2006-01-01

    Passive and active dosimeters worn on the trunk by the workers exposed to radiation fields at their workplaces measure the personal dose equivalent Hp(10), which was introduced by ICRP 60 to provide an appropriate estimate of the protection quantity: the effective dose E. However, the angular and energy distributions of the radiation fields encountered at workplaces can generate an over or an under-estimation of E because of the response of the dosimeters or/and because of the definition of H p(10) itself. That is why the Institute for Radiological Protection and Nuclear Safety (I.R.S.N.) is evaluating the possibility of the measurement of the effective dose E using an instrumented anthropomorphic phantom. The determination of the effective dose E in mixed neutron/photon fields requires to identify the nature and the energy distribution of the incident fields in order to apply the right radiation weighting factor to the mean absorbed doses. So electronic detectors will have to be placed on the surface and inside the phantom in order to identify the nature of the radiation field and to measure the mean absorbed dose within the organs. The positions and the technical characteristics of the detectors are determined by simulating the spatial distributions of the energy losses within organs and tissues of the phantom. The simulations are carried out with the Monte Carlo code M.C.N.P.X. using mesh tallies (virtual grid superimposed to the phantom geometry) and a mathematical model of an anthropomorphic phantom based on the specifications of Cristy and Eckerman. The processing of the first numerical results corresponding to photon irradiations in standard configurations (A.P., P.A. and L.A.T.) shows that for the following organs: the lungs, the liver, the small intestine and the brain, just one detector is enough and that this detector is not necessarily located at the center of the organ. On the other hand, the determination of the energy deposited in the red bone marrow

  11. A Monte Carlo-based model for simulation of digital chest tomo-synthesis

    International Nuclear Information System (INIS)

    Ullman, G.; Dance, D. R.; Sandborg, M.; Carlsson, G. A.; Svalkvist, A.; Baath, M.

    2010-01-01

    The aim of this work was to calculate synthetic digital chest tomo-synthesis projections using a computer simulation model based on the Monte Carlo method. An anthropomorphic chest phantom was scanned in a computed tomography scanner, segmented and included in the computer model to allow for simulation of realistic high-resolution X-ray images. The input parameters to the model were adapted to correspond to the VolumeRAD chest tomo-synthesis system from GE Healthcare. Sixty tomo-synthesis projections were calculated with projection angles ranging from + 15 to -15 deg. The images from primary photons were calculated using an analytical model of the anti-scatter grid and a pre-calculated detector response function. The contributions from scattered photons were calculated using an in-house Monte Carlo-based model employing a number of variance reduction techniques such as the collision density estimator. Tomographic section images were reconstructed by transferring the simulated projections into the VolumeRAD system. The reconstruction was performed for three types of images using: (i) noise-free primary projections, (ii) primary projections including contributions from scattered photons and (iii) projections as in (ii) with added correlated noise. The simulated section images were compared with corresponding section images from projections taken with the real, anthropomorphic phantom from which the digital voxel phantom was originally created. The present article describes a work in progress aiming towards developing a model intended for optimisation of chest tomo-synthesis, allowing for simulation of both existing and future chest tomo-synthesis systems. (authors)

  12. 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.)

  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. Computer tomographic and sonographic diagnosis of echinococcus

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, K.; Huebener, K.H.; Klott, K.; Jenss, H.; Baehr, R. (Tuebingen Univ. (Germany, F.R.). Medizinisches Strahleninstitut und Roentgenabteilung; Tuebingen Univ. (Germany, F.R.). Medizinische Klinik; Tuebingen Univ. (Germany, F.R.). Chirurgische Klinik und Poliklinik)

    1980-05-01

    In 33 patients (18 cystic echinococci, 15 alveolar) both methods produced the following findings which could be correlated with the pathological results: single or multi-centric lesions, sharp or indefinite demarkation and abnormalities in the shape and size of the liver. The sonographic findings were analysed with respect to the echo characteristics, whereas the computer tomographically demonstrated lesions were examined densitometrically in order to show calcification. Both methods demonstrate the pathological changes satisfactorily. Computer tomography is more effective in alveolar echinococcus lesions by showing the different types of calcification, whereas sonography provides a more accurate picture of the internal structure of the cysts in cystic echinococcus. Comparison of the methods in 19 patients examined by both showed a high accuracy in each method, but sonography was relatively poor in demonstrating lesions in the spleen.

  15. Computerized tomographic scanner with shaped radiation filter

    International Nuclear Information System (INIS)

    Carlson, R.W.; Walters, R.G.

    1981-01-01

    The invention comprises a shaped filter and a filter correction circuitry for computerized tomographic scanners. The shaped filter is a generally u-shaped block of filter material which is adapted to be mounted between the source of radiation and the scan circle. The u-shaped block has a parabolic recess. The filter material may be beryllium, aluminum, sulphur, calcium, titanium, erbium, copper, and compounds including oxides and alloys thereof. The filter correction circuit comprises a first filter correction profile adding circuit for adding a first scaler valve to each intensity valve in a data line. The data line is operated on by a beam hardness correction polynomial. After the beam hardness polynomial correction operation, a second filter correction circuit adds a second filter correction profile consisting of a table of scalor values, one corresponding to each intensity reading in the data line

  16. Occult fractures of the knee: tomographic evaluation

    International Nuclear Information System (INIS)

    Apple, J.S.; Martinez, S.; Allen, N.B.; Caldwell, D.S.; Rice, J.R.

    1983-01-01

    Seven adults with painful effusions of the knee were examined for occult fractures using pluridirectional tomograph in the coronal and lateral planes. Six patients (ages 50 to 82 years) were osteopenic and gave histories ranging from none to mild trauma; one 26-year-old man was not osteopenic and had severe trauma. In all cases, routine radiographs were interpreted as negative, but tomography demonstrated a fracture. Five fractures were subchondral. Bone scans in 2 patients were positive. The authors conclude that osteopenic patients with a painful effusion of the knee should be considered to have an occult fracture. While bone scans may be helpful, tomography is recommended as the procedure of choice to define the location and extent of the fracture

  17. Axial tomographic system for radiation diagnoses

    International Nuclear Information System (INIS)

    Crowther, T.J.

    1977-01-01

    The axial tomographic scanner consists of a source of hard radiation passing a fan shaped beam through a plane layer of the body under examination, a detector, and driving systems for the sequential displacement and rotation of the radiation source and the detector. The diagnosis is made by means of a data processing system offering extensive time overlap capability of the individual system functions. The data sets from transmission or absorption are processed in three independent subsystems, i.e., the scanning system, the processing system and the display system. The systems are made up of well-known modules, e.g., Nova 1200 or Eclipse 5200. Hence, as a result of the independent design of the data system, raw data will not be lost in case of faults in some subsystem. (DG) [de

  18. 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.

  19. E-learn Computed Tomographic Angiography

    DEFF Research Database (Denmark)

    Havsteen, Inger; Christensen, Anders; Nielsen, Jens K

    2012-01-01

    BACKGROUND: Computed tomographic angiography (CTA) is widely available in emergency rooms to assess acute stroke patients. To standardize readings and educate new readers, we developed a 3-step e-learning tool based on the test-teach-retest methodology in 2 acute stroke scenarios: vascular...... occlusion and "spot sign" in acute intracerebral hemorrhage. We hypothesized that an e-learning program enhances reading skills in physicians of varying experience. METHODS: We developed an HTML-based program with a teaching segment and 2 matching test segments. Tests were taken before and after...... sign correctly 69% before versus 92% after teaching (P = .009) and reported a median self-perceived diagnostic certainty of 50% versus 75% (P = .030). Self-perceived diagnostic certainty revealed no significant increase for vascular occlusion. CONCLUSIONS: The e-learning program is a useful educational...

  20. Computed tomographic findings of cerebral arterial ectasia

    International Nuclear Information System (INIS)

    Choi, Woo Suk; Ko, Young Ho; Lim, Jae Hoon

    1987-01-01

    The computed tomographic findings of cerebral arterial ectasia in 8 patients, of which 5 cases were angiographically documented, are reported. The ecstatic arteries, located predominantly in the suprasellar and interpeduncular cisterns, appeared as serpignous, tubular structures on the unenhanced scan. The enhanced CT scan demonstrated dense, sharply defined, homogeneous intraluminal enhancement. Until recently, the diagnosis of cerebral arterial ectasia was usually established by angiography. With introduction of CT it has become possible to noninvasively identify and characterize this vascular disorder and its associated intracranial complications. The vertebrobasilar dolichoectasia may be diagnosed by CT as an extra-axial lesion in the cerebellopontine angle. It enhances in a tubular fashion after intravenous injection of contrast.

  1. Computed tomographic investigations on intraventricular hematomas

    International Nuclear Information System (INIS)

    Laber-Szillat, S.

    1982-01-01

    This work investigated in 106 patients with intraventricular hematomas all the known factors which can have an influence on prognosis: age, sex, anamnesis of the patients, size, extent and localization of the intracranial bleeding, underlying angiopathy and differences between arterial and venous and spontaneous and traumatic bleedings. It was shown that the state of mind was the deciding prognostic factor, whereby viligance was the cumulative expression of all other investigated influences. A computed tomography (CT) examination is deciding in the question of operative hydrocephalus care. In 13 patients it was further shown, how clearly CT results and brain dissection allowed themselves to be compared. The computed tomographic examination method is best suited to achieve even physiological and more extensive prognostic possibilities. (orig.) [de

  2. Measurement of Patient Dose from Computed Tomography Using Physical Anthropomorphic Phantom

    International Nuclear Information System (INIS)

    Jang, Ki Won; Lee, Jae Ki; Kim, Jong Kyung

    2005-01-01

    The computed tomography (CT) provides a high quality in images of human body but contributes relatively high patient dose compared with the conventional X-ray examination. Furthermore, the frequency of CT examination has been increasing in Korea for the last decade owing to the national health insurance benefits. Increasing concerns about high patient dose from CT have stimulated a great deal of researches on dose assessment, which many of these are based on the Monte Carlo simulation. But in this study, absorbed doses and effective dose of patient undergoing CT examination were determined experimentally using anthropomorphic physical phantom and the measured results are compared with those from Monte Carlo calculation

  3. Tessier 3 Cleft in a Pre-Hispanic Anthropomorphic Figurine in El Salvador, Central America.

    Science.gov (United States)

    Aleman, Ramon Manuel; Martinez, Maria Guadalupe

    2017-03-01

    In 1976, Paul Tessier provided a numerical classification system for rare facial clefts, numbered from 0 to 14. The Tessier 3 cleft is a rare facial cleft extending from the philtrum of the upper lip through the wing of the nostril, and reaches the medial canthus of the eye. The aim of this document was to describe a pre-Hispanic anthropomorphic figurine dating from the classic period (200 A.D.-900 A.D.), which has a Tessier 3 cleft. We also discuss the documented pre-Hispanic beliefs about facial clefts.

  4. Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.

    Science.gov (United States)

    Koivisto, Juha H; Wolff, Jan E; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

    2015-07-08

    The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50-90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point-dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k = 2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low-dose limit. The sensitivity was 3.09 ± 0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was -8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD-comparable low-dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in

  5. Characterization of MOSFET dosimeters for low‐dose measurements in maxillofacial anthropomorphic phantoms

    Science.gov (United States)

    Wolff, Jan E.; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

    2015-01-01

    The aims of this study were to characterize reinforced metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low‐dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50–90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point‐dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k=2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low‐dose limit. The sensitivity was 3.09±0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was −8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD‐comparable low‐dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However

  6. Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom

    Directory of Open Access Journals (Sweden)

    Tian Hong Loh

    2014-08-01

    Full Text Available This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i an optical fibre; and (ii a metallic coaxial cable.

  7. Mind-Reading and Behavior-Reading against Agents with and without Anthropomorphic Features in a Competitive Situation

    Directory of Open Access Journals (Sweden)

    Kazunori Terada

    2017-07-01

    Full Text Available Humans use two distinct cognitive strategies separately to understand and predict other humans' behavior. One is mind-reading, in which an internal state such as an intention or an emotional state is assumed to be a source of a variety of behaviors. The other is behavior-reading, in which an actor's behavior is modeled based on stimulus-response associations without assuming internal states behind the behavior. We hypothesize that anthropomorphic features are key for an observer switching between these two cognitive strategies in a competitive situation. We provide support for this hypothesis through two studies using four agents with different appearances. We show that only a human agent was thought to possess both the ability to generate a variety of behaviors and internal mental states, such as minds and emotions (Study 1. We also show that humans used mixed (opposing strategies against a human agent and exploitative strategies against the agents with mechanical appearances when they played a repeated zero-sum game (Study 2. Our findings show that humans understand that human behavior is varied; that humans have internal states, such as minds and emotions; that the behavior of machines is governed by a limited number of fixed rules; and that machines do not possess internal mental states. Our findings also suggest that the function of mind-reading is to trigger a strategy for use against agents with variable behavior and that humans exploit others who lack behavioral variability based on behavior-reading in a competitive situation.

  8. Mind-Reading and Behavior-Reading against Agents with and without Anthropomorphic Features in a Competitive Situation.

    Science.gov (United States)

    Terada, Kazunori; Yamada, Seiji

    2017-01-01

    Humans use two distinct cognitive strategies separately to understand and predict other humans' behavior. One is mind-reading, in which an internal state such as an intention or an emotional state is assumed to be a source of a variety of behaviors. The other is behavior-reading, in which an actor's behavior is modeled based on stimulus-response associations without assuming internal states behind the behavior. We hypothesize that anthropomorphic features are key for an observer switching between these two cognitive strategies in a competitive situation. We provide support for this hypothesis through two studies using four agents with different appearances. We show that only a human agent was thought to possess both the ability to generate a variety of behaviors and internal mental states, such as minds and emotions (Study 1). We also show that humans used mixed (opposing) strategies against a human agent and exploitative strategies against the agents with mechanical appearances when they played a repeated zero-sum game (Study 2). Our findings show that humans understand that human behavior is varied; that humans have internal states, such as minds and emotions; that the behavior of machines is governed by a limited number of fixed rules; and that machines do not possess internal mental states. Our findings also suggest that the function of mind-reading is to trigger a strategy for use against agents with variable behavior and that humans exploit others who lack behavioral variability based on behavior-reading in a competitive situation.

  9. Tomographical evaluation of multifrequency-holography data in the ultrasonic testing of cylindrical components

    International Nuclear Information System (INIS)

    Kutzner, K.

    1986-01-01

    The data of multifrequency-holography on circle which were published in a previous paper were evaluated in a tomographical manner. For that the theoretical model which is the foundation of this measuring technique is converted into a Radon transform which can be inverted by standard methods. The results of this technique are compared with the results of the multifrequency-holography on circle. (orig./HP) [de

  10. Anthropomorphic measurements

    International Nuclear Information System (INIS)

    Wang, J.

    1998-01-01

    Based on decisions taken during the Research Coordination Meetings in Mito City 1988 and Bombay 1991, the participants were requested to provide data on physical measurement parameters of body height, body weight, sitting height, head circumference, neck circumference, chest circumference, chest width and chest depth which represented the age groups as newborn, 1 year, 5 years, 10 years, 15 years and adult 20-50 years. Accordingly, physical measurement data was obtained by participants from 9 countries

  11. A Simulation Study on Patient Setup Errors in External Beam Radiotherapy Using an Anthropomorphic 4D Phantom

    Directory of Open Access Journals (Sweden)

    Payam Samadi Miandoab

    2016-12-01

    Full Text Available Introduction Patient set-up optimization is required in radiotherapy to fill the accuracy gap between personalized treatment planning and uncertainties in the irradiation set-up. In this study, we aimed to develop a new method based on neural network to estimate patient geometrical setup using 4-dimensional (4D XCAT anthropomorphic phantom. Materials and Methods To access 4D modeling of motion of dynamic organs, a phantom employs non-uniform rational B-splines (NURBS-based Cardiac-Torso method with spline-based model to generate 4D computed tomography (CT images. First, to generate all the possible roto-translation positions, the 4D CT images were imported to Medical Image Data Examiner (AMIDE. Then, for automatic, real time verification of geometrical setup, an artificial neural network (ANN was proposed to estimate patient displacement, using training sets. Moreover, three external motion markers were synchronized with a patient couch position as reference points. In addition, the technique was validated through simulated activities by using reference 4D CT data acquired from five patients. Results The results indicated that patient geometrical set-up is highly depended on the comprehensiveness of training set. By using ANN model, the average patient setup error in XCAT phantom was reduced from 17.26 mm to 0.50 mm. In addition, in the five real patients, these average errors were decreased from 18.26 mm to 1.48 mm various breathing phases ranging from inhalation to exhalation were taken into account for patient setup. Uncertainty error assessment and different setup errors were obtained from each respiration phase. Conclusion This study proposed a new method for alignment of patient setup error using ANN model. Additionally, our correlation model (ANN could estimate true patient position with less error.

  12. Design Of A Low Cost Anthropomorphic Robot Hand For Industrial Applications

    Science.gov (United States)

    Allen, P.; Raleigh, B.

    2009-11-01

    Autonomous grasping systems using anthropomorphic robotic end effectors have many applications, and the potential of such devices has inspired researchers to develop many types of grasping systems over the past 30 years. Their research has yielded significant advances in end effector dexterity and functionality. However, due to the cost and complexity associated with such devices, their role has been largely confined to that of being research tools in laboratories. Industry, by contrast, has largely opted for simple, single task, devices. This paper presents a novel low cost anthropomorphic robotic end effector, and in particular the design characteristics that make it more applicable to industrial application. The design brief was (i) to be broadly similar to the human hand in terms of size and performance (ii) be low cost (less than €5000 for the system) and (iii) to provide sufficient performance to allow use in industrial applications. Consisting of three fingers and an opposing thumb, the robotic hand developed has a total of 12 automated degrees of freedom. Another 4 degrees of freedom can be set manually. The specific design of the fingers and thumb, together with the drive arrangement utilizing synchronous belts, yields a simplified kinematics solution for the control of movement. The modular nature of the design is extended also to the palm, which can be easily modified to produce different overall work envelopes for the hand. The drive system and grasping strategies are also detailed.

  13. In good company? Perception of movement synchrony of a non-anthropomorphic robot.

    Science.gov (United States)

    Lehmann, Hagen; Saez-Pons, Joan; Syrdal, Dag Sverre; Dautenhahn, Kerstin

    2015-01-01

    Recent technological developments like cheap sensors and the decreasing costs of computational power have brought the possibility of robotic home companions within reach. In order to be accepted it is vital for these robots to be able to participate meaningfully in social interactions with their users and to make them feel comfortable during these interactions. In this study we investigated how people respond to a situation where a companion robot is watching its user. Specifically, we tested the effect of robotic behaviours that are synchronised with the actions of a human. We evaluated the effects of these behaviours on the robot's likeability and perceived intelligence using an online video survey. The robot used was Care-O-bot3, a non-anthropomorphic robot with a limited range of expressive motions. We found that even minimal, positively synchronised movements during an object-oriented task were interpreted by participants as engagement and created a positive disposition towards the robot. However, even negatively synchronised movements of the robot led to more positive perceptions of the robot, as compared to a robot that does not move at all. The results emphasise a) the powerful role that robot movements in general can have on participants' perception of the robot, and b) that synchronisation of body movements can be a powerful means to enhance the positive attitude towards a non-anthropomorphic robot.

  14. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Taynna Vernalha Rocha [Faculdades Pequeno Principe (FPP), Curitiba, PR (Brazil); Cordova Junior, Arno Lotar; Almeida, Cristiane Maria; Piedade, Pedro Argolo; Silva, Cintia Mara da, E-mail: taynnavra@gmail.com [Centro de Radioterapia Sao Sebastiao, Florianopolis, SC (Brazil); Brincas, Gabriela R. Baseggio [Centro de Diagnostico Medico Imagem, Florianopolis, SC (Brazil); Marins, Priscila; Soboll, Danyel Scheidegger [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2016-03-15

    Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5- mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. (author)

  15. In good company? Perception of movement synchrony of a non-anthropomorphic robot.

    Directory of Open Access Journals (Sweden)

    Hagen Lehmann

    Full Text Available Recent technological developments like cheap sensors and the decreasing costs of computational power have brought the possibility of robotic home companions within reach. In order to be accepted it is vital for these robots to be able to participate meaningfully in social interactions with their users and to make them feel comfortable during these interactions. In this study we investigated how people respond to a situation where a companion robot is watching its user. Specifically, we tested the effect of robotic behaviours that are synchronised with the actions of a human. We evaluated the effects of these behaviours on the robot's likeability and perceived intelligence using an online video survey. The robot used was Care-O-bot3, a non-anthropomorphic robot with a limited range of expressive motions. We found that even minimal, positively synchronised movements during an object-oriented task were interpreted by participants as engagement and created a positive disposition towards the robot. However, even negatively synchronised movements of the robot led to more positive perceptions of the robot, as compared to a robot that does not move at all. The results emphasise a the powerful role that robot movements in general can have on participants' perception of the robot, and b that synchronisation of body movements can be a powerful means to enhance the positive attitude towards a non-anthropomorphic robot.

  16. Design, development, and implementation of the Radiological Physics Center's pelvis and thorax anthropomorphic quality assurance phantoms

    International Nuclear Information System (INIS)

    Followill, David S.; Radford Evans, DeeAnn; Cherry, Christopher; Molineu, Andrea; Fisher, Gary; Hanson, William F.; Ibbott, Geoffrey S.

    2007-01-01

    The Radiological Physics Center (RPC) developed two heterogeneous anthropomorphic quality assurance phantoms for use in verifying the accuracy of radiation delivery: one for intensity-modulated radiation therapy (IMRT) to the pelvis and the other for stereotactic body radiation therapy (SBRT) to the thorax. The purpose of this study was to describe the design and development of these two phantoms and to demonstrate the reproducibility of measurements generated with them. The phantoms were built to simulate actual patient anatomy. They are lightweight and water-fillable, and they contain imageable targets and organs at risk of radiation exposure that are of similar densities to their human counterparts. Dosimetry inserts accommodate radiochromic film for relative dosimetry and thermoluminesent dosimetry capsules for absolute dosimetry. As a part of the commissioning process, each phantom was imaged, treatment plans were developed, and radiation was delivered at least three times. Under these controlled irradiation conditions, the reproducibility of dose delivery to the target TLD in the pelvis and thorax phantoms was 3% and 0.5%, respectively. The reproducibility of radiation-field localization was less than 2.5 mm for both phantoms. Using these anthropomorphic phantoms, pelvic IMRT and thoracic SBRT radiation treatments can be verified with a high level of precision. These phantoms can be used to effectively credential institutions for participation in specific NCI-sponsored clinical trials

  17. Social categorization of social robots: anthropomorphism as a function of robot group membership.

    Science.gov (United States)

    Eyssel, Friederike; Kuchenbrandt, Dieta

    2012-12-01

    Previous work on social categorization has shown that people often use cues such as a person's gender, age, or ethnicity to categorize and form impressions of others. The present research investigated effects of social category membership on the evaluation of humanoid robots. More specifically, participants rated a humanoid robot that either belonged to their in-group or to a national out-group with regard to anthropomorphism (e.g., mind attribution, warmth), psychological closeness, contact intentions, and design. We predicted that participants would show an in-group bias towards the robot that ostensibly belonged to their in-group--as indicated by its name and location of production. In line with our hypotheses, participants not only rated the in-group robot more favourably--importantly, they also anthropomorphized it more strongly than the out-group robot. Our findings thus document that people even apply social categorization processes and subsequent differential social evaluations to robots. ©2011 The British Psychological Society.

  18. Development and liver of phantom anthropomorphic application for use in radiology

    International Nuclear Information System (INIS)

    Melo, M.G.; Silva, L.F.; Ferreira, F. C.L.; Cunha, C.J.; Paschoal, C.M.M.

    2015-01-01

    The use of artificial ionizing radiation has also been employed in several areas, namely: medicine, agriculture, industry, ink curing etc. However, the use of radiation for medical purposes of diagnosis or therapy is being treated with more attention due to its increased use and the use of simulators object for quality control and training of professionals. The phantoms and are used to aid radiographic procedures, they may simulate a part of the body, both in its form as mass, density, and attenuation. The objective of this work was the development and application of liver anthropomorphic phantom for use in diagnostic radiology and training professionals. The construction of the liver anthropomorphic phantom was through literature and it was noticed that the use of phantoms are relatively low. For the construction of the mold of the phantom was used an adult human liver with early cirrhosis that was preserved in formalin for teaching demonstrations in Prof. Human Anatomy Museum collection Osvaldo Cruz of milk from the Federal University of Sergipe. With this work, we emphasize the need for the control program and quality assurance in radiology doctor to ensure image quality and low exposure of patients and professionals, since the radiological examinations are extremely important, because its contribution decisively in medical diagnosis. (authors)

  19. 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

  20. Computed tomographic determination of tracheal dimensions in children and adolescents

    International Nuclear Information System (INIS)

    Griscom, N.T.

    1982-01-01

    A computed tomographic system for determining the internal diameters, cross-sectional area, and length of the trachea in children and adolescents was developed. Intraluminal volumes were calculated from these measurements.The results of 18 analyses are reported

  1. 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)

  2. Strategies for source space limitation in tomographic inverse procedures

    International Nuclear Information System (INIS)

    George, J.S.; Lewis, P.S.; Schlitt, H.A.; Kaplan, L.; Gorodnitsky, I.; Wood, C.C.

    1994-01-01

    The use of magnetic recordings for localization of neural activity requires the solution of an ill-posed inverse problem: i.e. the determination of the spatial configuration, orientation, and timecourse of the currents that give rise to a particular observed field distribution. In its general form, this inverse problem has no unique solution; due to superposition and the existence of silent source configurations, a particular magnetic field distribution at the head surface could be produced by any number of possible source configurations. However, by making assumptions concerning the number and properties of neural sources, it is possible to use numerical minimization techniques to determine the source model parameters that best account for the experimental observations while satisfying numerical or physical criteria. In this paper the authors describe progress on the development and validation of inverse procedures that produce distributed estimates of neuronal currents. The goal is to produce a temporal sequence of 3-D tomographic reconstructions of the spatial patterns of neural activation. Such approaches have a number of advantages, in principle. Because they do not require estimates of model order and parameter values (beyond specification of the source space), they minimize the influence of investigator decisions and are suitable for automated analyses. These techniques also allow localization of sources that are not point-like; experimental studies of cognitive processes and of spontaneous brain activity are likely to require distributed source models

  3. 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)

  4. 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

  5. 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...

  6. Tomographic inversion of P and pP data for aspherical mantle structure below the northwest Pacific region

    NARCIS (Netherlands)

    Hilst, R.D. van der; Engdahl, E.R.; Spakman, W.

    1993-01-01

    To investigate the morphology of subducted slab in the mantle below northwest Pacific island arcs we inverted traveltime residuals for aspherical variations in P-wave propagation velocity relative to the radially symmetric iasp91 reference model. The tomographic method used is based on a step-wise

  7. 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.

  8. 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.)

  9. 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)

  10. Computed tomographic findings of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Jo, In Su; Jong, Woo Yung; Lee, Jong Yul; Choi, Han Yong; Kim, Bong Ki

    1987-01-01

    With Development of Computed Tomography, detection of the Hepatocellular Carcinoma are easily performed and frequently used in the world. During 15 months, from December 1985 to February 1987, 59 patients with hepatocellular carcinoma were evaluated with computed tomography in department of radiology at Wallace Memorial Baptist Hospital. The results were as follow: 1. The most prevalent age group was 5th to 7th decades, male to female ratio was 4.9:1. 2. Classification with incidence of computed tomographic appearance of the hepatocellular carcinoma were solitary type 28 cases (48%), multinodular type 24 cases (40%), and diffuse type 7 cases (12%), Association with liver cirrhosis was noted in 22 cases (38%). 3. Inhomogenous internal consistency of hepatocellular carcinoma due to central necrosis were 35 cases (60%). Portal vein invasion by hepatocellular carcinoma was noted in 15 cases (25%), and particularly most common in diffuse type 4 cases (55%). 4. On precontrast scan, all hepatocellular carcinoma were seen as area of low density except for 3 cases(0.5%) of near isodensity which turned out to be remarkable low density on postcontrast scan. 5. In solitary type, posterior segment of right lobe was most common site of involvement 12 cases (43%). In diffuse type, bilobar involvement was most common, 6 cases (85%)

  11. 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.

  12. Computerized tomographic studies in cerebral palsy

    International Nuclear Information System (INIS)

    Sugie, Yoko

    1981-01-01

    Computed tomographic (CT) findings in 200 children with cerebral palsy (CP) were analysed from the viewpoint of clinical manifestations, disease complications and etiological factors. CT scans of 135 cases (67.5%) were found to be abnormal and there were 14 (7%) borderline cases. The major abnormality found on CT scans was cerebral atrophy. Other important changes included focal or diffuse low density area in the brain tissue, congenital malformation, and cerebellar atrophy. From the clinical point of view, a large number of patients with spastic tetraplegia and spastic diplegia showed highly abnormal CT scans. On the other hand, in patients with spastic monoplegia, spastic paraplegia, and athetotic type, CT findings were normal or revealed only minor cerebral atrophy. Most children showing asymmetric clinical symptoms had corresponding asymmetric CT abnormalities which included ventricular enlargement, low density area in the brain tissue, and hemispherical volume. There was a significant correlation between the severity of physical impairment and the extent of CT abnormalities. Severely affected children had grossly abnormal CT scans such as hydranencephaly, polycystic change, and extensive cerebral atrophy. In the patients complicated with epilepsy, the incidence and severity of abnormal CT were higher than those of non-epileptic patients. Mentally retarded patients had variable enlargement of the subarachnoidal space depending on the severity of their mental retardation. Patients with suspected postnatal etiology also had high incidence of severe CT abnormality. CT scan is a valuable tool for evaluating patients with CP and in some cases, possible etiology of the disease may be discovered. (author)

  13. Computed tomographic findings of intracerebral cysticercosis

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jin Kyo; Lee, Sun Wha; Kim, Ho Kyun; Ahn, Chi Yul [School of Medicine, Kyung-Hee University, Seoul (Korea, Republic of)

    1980-12-15

    Cysticercosis is a parasitic disease in which man serves as the intermediate host of Taenia Solium, the pork tapeworm. The computed tomographic findings of 25 cases of intracerebral cysticercosis proven by pathologic and/or clinical findings during past 2 years were analysed. The results were as follows; 1. The sex was 19 males and 6 females, and 56 percent of the patients were seen in fourth and fifth decades. The most common symptom was epilepsy (72%). 2. The C. T. findings in precontrast study were varied; such as ill defined low density (48%), cystic low density (20%), dilated ventricles (20%), ill defined low density with isodense nodule (18%), cystic low density with isodense mural nodule (12%) and calcification (8%). 3. The areas of involvement were 20 cases (80%) of parenchymal form, 3 cases (12%) of ventricular form and 2 cases (8%) of mixed form. 4. The contrast-enhanced 13 cases were 5 nodular, 5 ring or rim-like and 3 mixed type enhancements, while 12 cases were not enhanced. 5. C.T. scan demonstrated more precise location and extents of cerebral cysticercosis, especially in parenchymal form. It was considered to be important in determination of surgical feasibility and its approach.

  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. 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)

  16. 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

  17. Computed tomographic findings of cerebral paragonimiasis

    International Nuclear Information System (INIS)

    Sung, Nak Kwan; Nam, Kyung Jin; Park, Churl Min; Eun, Chung Kie; Lee, Sun Wha

    1983-01-01

    Paragonimiasis is widely distributed in Far East and Southeast Asia, particularly in Korea. The central nervous system is the most frequent location for paragonimiasis outside the lungs. We analyzed the computed tomographic findings of 17 cases which were diagnosed pathologically and clinically as cerebral paragonimiasis. The results were as follows: 1. The ratio of male to female was 10 : 7 and about 88% of cases were under the age of 40 years. 2. The common locations of cerebral paragonimiasis were the occipital (12 cases) and temporal (11 cases) lobes. 3. Precontrast CT findings of cerebral paragonimiasis were low density with calcifications in 6 cases, low and isodensities in 4 cases, mixed densities in 3 cases, only low density in 2 cases and only calcification in 2 cases. Hydrocephalus (7 cases), mass effect (6 cases), atrophic change (6 cases) and cyst formation (3 cases) were associated. 4. The shape of calcifications in CT scan were soap-bubble or ring in 6 cases, nodular or oval in 6 cases, stipple in 4 cases and amorphous conglomerated in 2 cases. 5. The contrast -enhanced 8 cases were 5 ring or rim like, 2 nodular and 1 irregular enhancements, while 9 cases were not enhanced

  18. 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)

  19. ROC evaluation of SPECT myocardial lesion detectability with and without single iteration non-uniform Chang attenuation compensation using an anthropomorphic female phantom

    International Nuclear Information System (INIS)

    Jang, S.; Jaszczak, R.J.; Duke Univ. Medical Center, Durham, NC; Gilland, D.R.; Turkington, T.G.; Coleman, R.E.; Tsui, B.M.W.; Metz, C.E.

    1998-01-01

    The purpose of this work was to evaluate lesion detectability with and without nonuniform attenuation compensation (AC) in myocardial perfusion SPECT imaging in women using an anthropomorphic phantom and receiver operating characteristics (ROC) methodology. Breast attenuation causes artifacts in reconstructed images and may increase the difficulty of diagnosis of myocardial perfusion imaging in women. The null hypothesis tested using the ROC study was that nonuniform AC does not change the lesion detectability in myocardial perfusion SPECT imaging in women. The authors used a filtered backprojection (FBP) reconstruction algorithm and Chang's single iteration method for AC. In conclusion, with the proposed myocardial defect model nuclear medicine physicians demonstrated no significant difference for the detection of the anterior wall defect; however, a greater accuracy for the detection of the inferior wall defect was observed without nonuniform AC than with it. Medical physicists did not demonstrate any statistically significant difference in defect detection accuracy with or without nonuniform AC in the female phantom

  20. Inter- and intrascanner variability of pulmonary nodule volumetry on low-dose 64-row CT : an anthropomorphic phantom study

    NARCIS (Netherlands)

    Xie, X.; Willemink, M. J.; Zhao, Y.; de Jong, P. A.; van Ooijen, P. M. A.; Oudkerk, M.; Greuter, M. J. W.; Vliegenthart, R.

    Objective: To assess inter- and intrascanner variability in volumetry of solid pulmonary nodules in an anthropomorphic thoracic phantom using low-dose CT. Methods: Five spherical solid artificial nodules [diameters 3, 5, 8, 10 and 12mm; CT density 1100 Hounsfield units (HU)] were randomly placed

  1. 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.

  2. 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)

  3. 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)

  4. Kinematic design of a finger abduction mechanism for an anthropomorphic robotic hand

    Directory of Open Access Journals (Sweden)

    L.-A. A. Demers

    2011-02-01

    Full Text Available This paper presents the kinematic design of an abduction mechanism for the fingers of an underactuated anthropomorphic robotic hand. This mechanism will enhance the range of feasible grasps of the underactuated hand without significantly increasing its complexity. The analysis of the link between the index finger and the third finger is first assessed, where the parameters are studied in order to follow the amplitude constraint and to minimize the coordination error. Then, the study of the mechanism joining the third finger and the little finger is summarized. Finally, a prototype of the finger's abduction system is presented.

    This paper was presented at the IFToMM/ASME International Workshop on Underactuated Grasping (UG2010, 19 August 2010, Montréal, Canada.

  5. Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom

    DEFF Research Database (Denmark)

    Jonasson, L S; Axelsson, J; Riklund, K

    2017-01-01

    In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET...... cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events...... from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered-subsets maximization algorithm with spatially variant point-spread function...

  6. Development and application of anthropomorphic voxel phantom of the head for in vivo measurement.

    Science.gov (United States)

    Vrba, T

    2007-01-01

    The in vivo measurement of the activity deposited in the skeleton is a very useful source of information on human internal contaminations with transuranic elements, e.g. americium 241, especially for long time periods after intake. Measurements are performed on the skull or the larger joints such as the knee or elbow. The paper deals with the construction of an anthropomorphic numerical phantom based on CT scans, its potential for calibration and the estimation of the uncertainties of the detection system. The density of bones, activity distribution and position of the detectors were changed in individual simulations in order to estimate their effects on the result of the measurement. The results from simulations with the numerical phantom were compared with the results of physical phantoms.

  7. Bases for calibration of whole body counters using anthropomorphic physical simulators

    International Nuclear Information System (INIS)

    Dantas, Bernardo Maranhao

    1998-01-01

    The quantification of radionuclides in the human body can be carried out through in vivo measurements performed in facilities generically called whole body counters. The calibration of such units is usually done by using physical anthropomorphic phantoms, which can be defined as artificial structures with geometrical characteristics and attenuation properties similar to the living tissues. This work presents the development of the phantoms necessary to the monitoring of the internal contamination by the radionuclides manipulated in Brazil. It also presents the procedures for the calibration of the detectors used for the in vivo measurements. The developed phantoms are applied in the determination of radionuclides deposited in specific organs, such as Th-232 and Am-241 in the lungs and skull, isotopes of iodine in the thyroid and photon emitters in the energy range from 100 to 3000 keV in the whole body. (author)

  8. Fatal Attractions: Attachment to Smartphones Predicts Anthropomorphic Beliefs and Dangerous Behaviors.

    Science.gov (United States)

    Bodford, Jessica E; Kwan, Virginia S Y; Sobota, David S

    2017-05-01

    As technology's presence grows increasingly concrete in global societies, so too do our relationships with the devices we keep close at hand from day to day. Whereas research has, in the past, framed smartphone addiction in terms of possessional attachment, the present research hypothesizes that anxious smartphone attachment stems from human attachment, in which Anxiously attached individuals may be more likely to generalize their anxious attachment style to communication devices. In the present study, we found support for this hypothesis and showed that anxious smartphone attachment predicts (1) anthropomorphic beliefs, (2) reliance on-or "clinginess" toward-smartphones, and (3) a seemingly compulsive urge to answer one's phone, even in dangerous situations (e.g., while driving). Taken together, we seek to provide a theoretical framework and methodological tools to identify the sources of technology attachment and those most at risk of engaging in dangerous or inappropriate behaviors as a result of attachment to ever-present mobile devices.

  9. The application of shape memory actuators in anthropomorphic upper limb prostheses.

    Science.gov (United States)

    dos Santos, Christian Mariani Lucas; da Cunha, Fransergio Leite; Dynnikov, Vladimir Ivanovitch

    2003-05-01

    In recent years, single crystal Cu-Al-Ni alloys with shape memory behavior (SMB) became generally commercialized. They achieved the level of extended application, including upper limb human prosthesis with anthropomorphic characteristics. An actuator based in single crystal Cu-Al-Ni alloy was tested as a prototype for prosthetic actuators. Their thermal cycle times remarkably define the actuator dynamics and the idea of preheating to reduce its response time was tested. To elaborate the heating conditions, the chemical composition of martensitic and austenitic single crystals, Cu-Al-Ni alloy samples were examined. The dynamic response of a martensitic actuator made with SMB and the power consumed with preheating was analyzed. It demonstrates that the presence of more elements in alloys may be fundamental to displace the heating diagram and to reduce the power consumed.

  10. Contextual analysis of fragmentation of the anthropomorphic figurines from the Late Neolithic site of Selevac

    Directory of Open Access Journals (Sweden)

    Marko Porčić

    2016-03-01

    Full Text Available The biographical approach to material culture and the hypothesis of deliberate fragmentation of anthropomorphic figurines are used in this paper to deduce a hypothesis that there should be an association between particular fragmentation categories and context types in the archaeological record of the Late Neolithic settlements in Central Balkans. This hypothesis is tested using published data from the site of Selevac by performing correspondence analysis and chi-square test on a contingency table in which categories of fragmentation are cross-tabulated with context types. The results are statistically significant, suggesting that complete figurines are associated with houses while transversely broken figurines are associated with pits. There is also evidence that figurines were broken differentially in respect to their original size.

  11. TU-G-BRD-05: Results From Multi-Institutional Measurements with An Anthropomorphic Spine Phantom

    International Nuclear Information System (INIS)

    Molineu, A; Hernandez, N; Alvarez, P; Followill, D

    2015-01-01

    Purpose: To analyze the results from an anthropomorphic spine phantom used for credentialing institutions for National Cancer Institute (NCI) sponsored clinical trial. Methods: An anthropomorphic phantom that contains left and right lungs, a heart, an esophagus, spinal cord, bony material and a PTV was sent to institutions wishing to be credentialed for NCI trials. The PTV holds 4 TLD and radiochromic film in the axial and sagittal planes. The heart holds one TLD. Institutions created IMRT plans to cover ≥90% of the PTV with 6 Gy and limit the cord dose to <0.35cc receiving 3.75 Gy and <1.2cc receiving 2.63 Gy. They were instructed to treat the phantom as they would a patient, including making plan specific IMRT/SBRT QA measurements before treatment. The TLD results in the PTV were required to be within ±7% of the plan dose. A gamma calculation was performed using the film results and the submitted DICOM plan. ≥85% of the analyzed region was required to pass a 5%/3 mm criteria. Results: 176 institutions irradiated the spine phantom for a total of 255 results. The pass rate was 73% (187 irradiations) overall. 44 irradiations failed only the gamma criteria, 2 failed only the dose criteria and 22 failed both. The most used planning systems were Eclipse (116) and Pinnacle (52) and they had pass rates of 76% and 71%, respectively. The AAA algorithm had a pass rate of 77% while superposition type algorithms had a 71% pass rate. The average TLD measurement to institution calculation ratio was 0.99 (0.04 std dev.). The average percent pixels passing the gamma criteria for films was 89% (12% std dev.) Conclusion: Results show that this phantom is an important part of credentialing and that we have room for improvement in IMRT/SBRT spine treatments. This work was supported by PHS CA180803 and CA037422 awarded by NCI, DHHS

  12. Design, manufacture, and evaluation of an anthropomorphic pelvic phantom purpose-built for radiotherapy dosimetric intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, K. M.; Ebert, M. A.; Kron, T.; Howlett, S. J.; Cornes, D.; Hamilton, C. S.; Denham, J. W. [Department of Radiation Oncology, Calvary Mater Newcastle, Waratah, New South Wales 2298, Australia and School of Physics, University of Newcastle, New South Wales 2308 (Australia); Department of Radiation Oncology, Sir Charles Gairdner Hospital, Western Australia, Australia and School of Physics, University of Western Australia, Western Australia 6009 (Australia); Department of Physical Sciences, Peter MacCallum Cancer Centre, Victoria 8006 (Australia); Australiasian College of Physical Scientists and Engineers in Medicine, Sydney, New South Wales 2020 (Australia); Trans-Tasman Radiation Oncology Group, Calvary Mater Newcastle, New South Wales 2298 (Australia); Heidelberg Repatriation Hospital, Victoria 3081 (Australia); Department of Radiation Oncology, Calvary Mater Newcastle, Waratah, New South Wales 2298, Australia and School of Medicine and Population Health, University of Newcastle, New South Wales 2308 (Australia)

    2011-10-15

    Purpose: An anthropomorphic pelvic phantom was designed and constructed to meet specific criteria for multicenter radiotherapy dosimetric intercomparison. Methods: Three dimensional external and organ outlines were generated from a computed tomography image set of a male pelvis, forming the basis of design for an anatomically realistic phantom. Clinically relevant points of interest were selected throughout the dataset where point-dose values could be measured with thermoluminescence dosimeters and a small-volume ionization chamber. Following testing, three materials were selected and the phantom was manufactured using modern prototyping techniques into five separate coronal slices. Time lines and resource requirements for the phantom design and manufacture were recorded. The ability of the phantom to mimic the entire treatment chain was tested. Results: The phantom CT images indicated that organ densities and geometries were comparable to those of the original patient. The phantom proved simple to load for dosimetry and rapid to assemble. Due to heat release during manufacture, small air gaps and density heterogeneities were present throughout the phantom. The overall cost for production of the prototype phantom was comparable to other commercial anthropomorphic phantoms. The phantom was shown to be suitable for use as a ''patient'' to mimic the entire treatment chain for typical external beam radiotherapy for prostate and rectal cancer. Conclusions: The phantom constructed for the present study incorporates all characteristics necessary for accurate Level III intercomparison studies. Following use in an extensive Level III dosimetric comparison over a large time scale and geographic area, the phantom retained mechanical stability and did not show signs of radiation-induced degradation.

  13. 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

  14. 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

  15. Quantitative analysis of normal thallium-201 tomographic studies

    International Nuclear Information System (INIS)

    Eisner, R.L.; Gober, A.; Cerqueira, M.

    1985-01-01

    To determine the normal (nl) distribution of Tl-201 uptake post exercise (EX) and at redistribution (RD) and nl washout, Tl-201 rotational tomographic (tomo) studies were performed in 40 subjects: 16 angiographic (angio) nls and 24 nl volunteers (12 from Emory and 12 from Yale). Oblique angle short axis slices were subjected to maximal count circumferential profile analysis. Data were displayed as a ''bullseye'' functional map with the apex at the center and base at the periphery. The bullseye was not uniform in all regions because of the variable effects of attenuation and resolution at different view angles. In all studies, the septum: lateral wall ratio was 1.0 in males and approximately equal to 1.0 in females. This occurred predominantly because of anterior defects due to breast soft tissue attenuation. EX and RD bullseyes were similar. Using a bi-exponential model for Tl kinetics, 4 hour normalized washout ranged 49-54% in each group and showed minimal variation between walls throughout the bullseye. Thus, there are well defined variations in Tl-201 uptake in the nl myocardium which must be taken into consideration when analyzing pt data. Because of these defects and the lack of adequate methods for attenuation correction, quantitative analysis of Tl-201 studies must include direct comparison with gender-matched nl data sets

  16. Computed tomographic findings of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Eun, Chung Kie [Kyung Hee University College of Medicine, Seoul (Korea, Republic of)

    1982-09-15

    It is well known that CT is very useful in the evaluation of hepatocellular carcinoma. The computed tomographic findings of 56 patients diagnosed as hepatocellular carcinoma were reviewed and analyzed. The results were as follows: 1. The male to female ratio was 3 : 1 and the age ranged from 31 to 73 years with average age of 54 years. 2. Alpha-fetoprotein was positive in 19 out of 38 cases (50%). HBsAg was positive in 8 out of 33 cases (24%). 3. All lesions were seen as areas of low density except 1 case (0%) of isodensity, and 40 cases (72%) appeared to be solitary while 15 (26%) were multifocal. The low density was homogenous in 13 cases (24%) and inhomogenous in 42 cases (76%), and 18 cases out of 42 cases inhomogenous low density showed peripheal and/or central nodular enhancement. The additional findings were contour changes in 37 cases (66%), metastasis in 35 cases (63%), splenomegaly in 23 cases (42%) and ascities in 22 cases (39%). 4. In postcontrast scans, 41 cases (80%) out of 51 cases showed the change of density after contrast infusion. The presence and extent of tumors were better seen after contrast infusion in 30 cases (59%), better seen before contrast infusion in 11 cases (21%) and no significant difference before and after contrast infusion in 10 cases (20%). 5. The sites of involved lobe were right lobe in 38 cases (68%), left lobe in 5 cases (9%) and both lobes in 13 cases (23%). 6. 35 cases (63%) showed evidence of metastasis to regional lymph nodes, organ or tissues.

  17. Computed tomographic findings of cerebral paragonimiasis

    International Nuclear Information System (INIS)

    Bae, Weon Tae; Jung, Min Ki; Kang, Heoung Keun; Chung, Hyon De

    1988-01-01

    Authors analyzed the computed tomographic (CT) findings of 19 cases pathologically and clinically proven cerebral paragonimiasis that were performed at Chonnam University Hospital from April 1983 through March 1987. The results were as follows: 1. Male to female ratio was 15:4 and the most prevalent age group was 3rd decade (7 cases). The common symptoms were epileptic seizure (16 cases) and headache (12 cases). 2. The multiplicity of cerebral paragonimiasis was 7 of 19 cases and the distributions of lesion were occipital (11 cases), temporal (6 cases), frontal (5 cases) and parietal (5 cases) lobe. 3. The calcification on CT scan were single (7 cases) or multiple (7 cases) and the shape of calcification were nodular (10 cases), soap babble of ring (8 cases), and stippled (6 cases). The pattern of contrast enhancement were ring (5 cases) or nodular (1 case), and along the basal cistern (1 case with arachnoiditis). 4. 12 out of 13 cases, had long clinical symptoms over 3 years with calcifications, could be analyzed according to Valentine's vascular territory; 6 cases in PCA territory, 3 in MCA and 3 in ACA. 5. CT findings were noted according to the duration of symptoms; 5 cases, had symptoms less than 1 year, showed abscess (5 cases) and arachnoiditis (1 case) with brain edema, mass effect, hydrocephalus and contrast enhancement but no calcification in all. One case, had symptom of 1 year and 2 months, showed partially calcified granulomatous lesion with perifocal edema and contrast enhancement, 13 cases, had symptoms over 3 years, showed multiple calcification with brain atrophy (10 cases), but no contrast enhancement in all cases.

  18. Tomographic analysis of CBF in cerebral infarction

    International Nuclear Information System (INIS)

    Segawa, Hiromu; Kimura, Kazumoto; Ueda, Yuichi; Nagai, Masakatsu; Yoshimasu, Norio.

    1983-01-01

    Cerebral perfusion was examined in various types of occlusive disease by computed tomographic CBF method. The method utilized has several advantages over conventional studies using isotope, providing high resolution images in a direct relation to CT anatomy. Ten representative cases were presented from 25 consective cases of occlusive disease studied by this method. The method included inhalation of 40 to 60% xenon with serial CT scanning for 25 min. K (build-up rate), lambda (partition coefficient) and CBF values were calculated from ΔHU for each pixel and ΔXe in expired air, based on Fick's principle, and displayed on CRT as K-, lambda- and CBF-map separately. CBF for gray matter of normal control was 82 +- 11 ml/100 gm/min and that for white matter was 24 +- 5 ml/100 gm/min. The ischemic threshold for gray matter appeared to be approximately 20 ml/100 gm/min, as blood flow in focus of complete infarction was below this level. Blood flow between 20 - 30 ml/ 100 gm/min caused some change on CT, such as localized atrophy, cortical thinning, loss of distinction between gray and white matter and decreased or increased density, which were considered to be compatible with pathological changes of laminar necrosis or gliosis with neuronal loss. In a case with occlusion of middle cerebral artery with subsequent recanalization, causing hemorrhagic infarct, hyperemia was observed in the infarcted cortex that was enhanced by iodine. Periventricular lucency observed in two cases, where blood flow was decreased below threshold, could be classified as ''watershed infarction'' mainly involving white matter. In moyamoya disease, blood flow in the anterior circulation was decreased near ischemic level, whereas that in basal ganglia and territory of posterior cerebral artery was fairly preserved, which was compatible with general angiographic finding of this disease. (author)

  19. Numerical absorbed dose distributions inside principal organs of a mathematical anthropomorphic phantom irradiated by monoenergetic photon fields

    International Nuclear Information System (INIS)

    Furstoss, C.; Menard, S.

    2005-01-01

    Full text: Personnel can be exposed to photon or mixed (neutrons and photons) radiations at workplaces for various activities (nuclear fuel cycle, medical sector, research... ). The passive and active personal dosimeters worn on the trunk evaluate the personal dose equivalent Hp(10), defined by ICRP 601 to be an estimator of the effective dose E. However, the angular and energy distributions of the radiations encountered could generate an over or under-estimation of the protection quantity E because of the response of the dosimeters or/and because of the definition of Hp(10) itself. The Institute of Radiological Protection and Nuclear Safety (IRSN) is evaluating the possibility of the measurement of the effective dose E using an instrumented anthropomorphic phantom at workplaces. Such an instrument would allow the control of the suitability of the radiological protection instrumentation used at workplaces for radiation fields which can appreciably differ from the reference ISO radiation fields used to calibrate dosimeters. The objectives of this study are to determine key positions for the future detectors inside and on the phantom, as well as their needed technical characteristics. The simulations of the organ absorbed dose distributions performed using the Monte Carlo code MCNPX2 and the MIRD phantom3 model will allow the determination of the detector locations. This paper will present the first numerical results obtained for monoenergetic parallel photon fields. The effective doses E calculated in an energy range from 15 keV to 10 MeV will be presented and compared with the results of M. Zankl et al., published in the GSF report Bericht 8/974. (author)

  20. New method to analyze internal disruptions with tomographic reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tanzi, C.P. [EURATOM-FOM Association, FOM-Instituut voor Plasmafysica Rijnhuizen, P.O. BOX 1207, 3430 BE Nieuwegein (The Netherlands); de Blank, H.J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-IPP Association, 85740 Garching (Germany)

    1997-03-01

    Sawtooth crashes have been investigated on the Rijnhuizen Tokamak Project (RTP) [N. J. Lopes Cardozo {ital et al.}, {ital Proceedings of the 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research}, W{umlt u}rzburg, 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271]. Internal disruptions in tokamak plasmas often exhibit an m=1 poloidal mode structure prior to the collapse which can be clearly identified by means of multicamera soft x-ray diagnostics. In this paper tomographic reconstructions of such m=1 modes are analyzed with a new method, based on magnetohydrodynamic (MHD) invariants computed from the two-dimensional emissivity profiles, which quantifies the amount of profile flattening not only after the crash but also during the precursor oscillations. The results are interpreted by comparing them with two models which simulate the measurements of the m=1 redistribution of soft x-ray emissivity prior to the sawtooth crash. One model is based on the magnetic reconnection model of Kadomtsev. The other involves ideal MHD motion only. In cases where differences in magnetic topology between the two models cannot be seen in the tomograms, the analysis of profile flattening has an advantage. The analysis shows that in RTP the clearly observed m=1 displacement of some sawteeth requires the presence of convective ideal MHD motion, whereas other precursors are consistent with magnetic reconnection of up to 75{percent} of the magnetic flux within the q=1 surface. The possibility of ideal interchange combined with enhanced cross-field transport is not excluded. {copyright} {ital 1997 American Institute of Physics.}

  1. New method to analyze internal disruptions with tomographic reconstructions

    International Nuclear Information System (INIS)

    Tanzi, C.P.; de Blank, H.J.

    1997-01-01

    Sawtooth crashes have been investigated on the Rijnhuizen Tokamak Project (RTP) [N. J. Lopes Cardozo et al., Proceedings of the 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Wuerzburg, 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271]. Internal disruptions in tokamak plasmas often exhibit an m=1 poloidal mode structure prior to the collapse which can be clearly identified by means of multicamera soft x-ray diagnostics. In this paper tomographic reconstructions of such m=1 modes are analyzed with a new method, based on magnetohydrodynamic (MHD) invariants computed from the two-dimensional emissivity profiles, which quantifies the amount of profile flattening not only after the crash but also during the precursor oscillations. The results are interpreted by comparing them with two models which simulate the measurements of the m=1 redistribution of soft x-ray emissivity prior to the sawtooth crash. One model is based on the magnetic reconnection model of Kadomtsev. The other involves ideal MHD motion only. In cases where differences in magnetic topology between the two models cannot be seen in the tomograms, the analysis of profile flattening has an advantage. The analysis shows that in RTP the clearly observed m=1 displacement of some sawteeth requires the presence of convective ideal MHD motion, whereas other precursors are consistent with magnetic reconnection of up to 75% of the magnetic flux within the q=1 surface. The possibility of ideal interchange combined with enhanced cross-field transport is not excluded. copyright 1997 American Institute of Physics

  2. 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...

  3. 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...

  4. 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

  5. Synchronized multiartifact reduction with tomographic reconstruction (SMART-RECON): A statistical model based iterative image reconstruction method to eliminate limited-view artifacts and to mitigate the temporal-average artifacts in time-resolved CT.

    Science.gov (United States)

    Chen, Guang-Hong; Li, Yinsheng

    2015-08-01

    In x-ray computed tomography (CT), a violation of the Tuy data sufficiency condition leads to limited-view artifacts. In some applications, it is desirable to use data corresponding to a narrow temporal window to reconstruct images with reduced temporal-average artifacts. However, the need to reduce temporal-average artifacts in practice may result in a violation of the Tuy condition and thus undesirable limited-view artifacts. In this paper, the authors present a new iterative reconstruction method, synchronized multiartifact reduction with tomographic reconstruction (SMART-RECON), to eliminate limited-view artifacts using data acquired within an ultranarrow temporal window that severely violates the Tuy condition. In time-resolved contrast enhanced CT acquisitions, image contrast dynamically changes during data acquisition. Each image reconstructed from data acquired in a given temporal window represents one time frame and can be denoted as an image vector. Conventionally, each individual time frame is reconstructed independently. In this paper, all image frames are grouped into a spatial-temporal image matrix and are reconstructed together. Rather than the spatial and/or temporal smoothing regularizers commonly used in iterative image reconstruction, the nuclear norm of the spatial-temporal image matrix is used in SMART-RECON to regularize the reconstruction of all image time frames. This regularizer exploits the low-dimensional structure of the spatial-temporal image matrix to mitigate limited-view artifacts when an ultranarrow temporal window is desired in some applications to reduce temporal-average artifacts. Both numerical simulations in two dimensional image slices with known ground truth and in vivo human subject data acquired in a contrast enhanced cone beam CT exam have been used to validate the proposed SMART-RECON algorithm and to demonstrate the initial performance of the algorithm. Reconstruction errors and temporal fidelity of the reconstructed

  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. Design and manufacturing of anthropomorphic thyroid-neck phantom for use in nuclear medicine centres in Chile

    International Nuclear Information System (INIS)

    Hermosilla, A.; Diaz Londono, G.; Garcia, M.; Ruiz, F.; Andrade, P.; Perez, A.

    2014-01-01

    Anthropomorphic phantoms are used in nuclear medicine for imaging quality control, calibration of gamma spectrometry system for the study of internal contamination with radionuclides and for internal dosimetric studies. These are constructed of materials that have radiation attenuation coefficients similar to those of the different organs and tissues of the human body. The material usually used for the manufacture of phantoms is polymethyl methacrylate. Other materials used for this purpose are polyethylene, polystyrene and epoxy resin. This project presents the design and manufacture of an anthropomorphic thyroid-neck phantom that includes the cervical spine, trachea and oesophagus, using a polyester resin (ρ 1.1 g cm -3 ). Its linear and mass attenuation coefficients were experimentally determined and simulated by means of XCOM software, finding that this material reproduces the soft tissue ICRU-44 in a range of energies between 80 keV and 11 MeV, with less than a 5 % difference. (authors)

  8. Evaluation of the usefulness of a MOSFET detector in an anthropomorphic phantom for 6-MV photon beam.

    Science.gov (United States)

    Kohno, Ryosuke; Hirano, Eriko; Kitou, Satoshi; Goka, Tomonori; Matsubara, Kana; Kameoka, Satoru; Matsuura, Taeko; Ariji, Takaki; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

    2010-07-01

    In order to evaluate the usefulness of a metal oxide-silicon field-effect transistor (MOSFET) detector as a in vivo dosimeter, we performed in vivo dosimetry using the MOSFET detector with an anthropomorphic phantom. We used the RANDO phantom as an anthropomorphic phantom, and dose measurements were carried out in the abdominal, thoracic, and head and neck regions for simple square field sizes of 10 x 10, 5 x 5, and 3 x 3 cm(2) with a 6-MV photon beam. The dose measured by the MOSFET detector was verified by the dose calculations of the superposition (SP) algorithm in the XiO radiotherapy treatment-planning system. In most cases, the measured doses agreed with the results of the SP algorithm within +/-3%. Our results demonstrated the utility of the MOSFET detector for in vivo dosimetry even in the presence of clinical tissue inhomogeneities.

  9. 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

  10. Radiation exposure of lens, thyroid gland and testis in anthropomorphic phantom during CT examination and its protective measures

    International Nuclear Information System (INIS)

    Dai Suhua; Weng Zhigen; Wu Caifa

    1995-01-01

    The SMN-I anthropomorphic phantom was used to simulate patients and to estimate the radiation exposure of lens, thyroid gland and testes during CT examination according to hospital routine managements. The results show that the X-ray radiation doses received by the organs mentioned above are different in good and no protection shelter. Therefore, during CT examination it's of great significance to take a good protective shelter for organs which are near the CT scanning areas

  11. Calculation of dose in anthropomorphic dummies ICRP 110 simulation of protocols overall for a team of 320 sections TC

    International Nuclear Information System (INIS)

    Cros Torrents, M.; Geleijns, J.; Salvador Artells, M.

    2013-01-01

    The objective of this study is to carry out, using a program of simulation Monte Carlo, an estimate of the dose received in anthropomorphic mannequins voxelized in tests of four protocols established for the Aquilion ONE General acquiring in conical beam of 320 X 0, 5 mm. Finally, will be obtained factors of conversion between values of product dose (DLP) length and effective doses for each protocol. (Author)

  12. Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy

    OpenAIRE

    Dana J Lewis; Paige A Summers; David S Followill; Narayan Sahoo; Anita Mahajan; Francesco C Stingo; Stephen F Kry

    2014-01-01

    Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC) Houston QA Center (formerly RPC).Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS), and proton treatment delivery. The design incorporated materials simulating the ...

  13. A maximum-likelihood reconstruction algorithm for tomographic gamma-ray nondestructive assay

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Estep, R.J.; Cole, R.A.; Sheppard, G.A.

    1994-01-01

    A new tomographic reconstruction algorithm for nondestructive assay with high resolution gamma-ray spectroscopy (HRGS) is presented. The reconstruction problem is formulated using a maximum-likelihood approach in which the statistical structure of both the gross and continuum measurements used to determine the full-energy response in HRGS is precisely modeled. An accelerated expectation-maximization algorithm is used to determine the optimal solution. The algorithm is applied to safeguards and environmental assays of large samples (for example, 55-gal. drums) in which high continuum levels caused by Compton scattering are routinely encountered. Details of the implementation of the algorithm and a comparative study of the algorithm's performance are presented

  14. Evaluation of tomographic ISOCAM Park II gamma camera parameters using Monte Carlo method

    International Nuclear Information System (INIS)

    Oramas Polo, Ivón

    2015-01-01

    In this paper the evaluation of tomographic ISOCAM Park II gamma camera parameters was performed using the Monte Carlo code SIMIND. The parameters uniformity, resolution and contrast were evaluated by Jaszczak phantom simulation. In addition the qualitative assessment of the center of rotation was performed. The results of the simulation are compared and evaluated against the specifications of the manufacturer of the gamma camera and taking into account the National Protocol for Quality Control of Nuclear Medicine Instruments of the Cuban Medical Equipment Control Center. A computational Jaszczak phantom model with three different distributions of activity was obtained. They can be used to perform studies with gamma cameras. (author)

  15. 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)

  16. 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.

  17. Computer tomographic detection of an intraspinal arachnoidal cyst

    Energy Technology Data Exchange (ETDEWEB)

    Kuckein, D; Walter, K; Paal, G

    1981-03-01

    A 46 year old female patient who after 3-4 weeks of influenza suffered from strong headaches, vomiting and rotatory vertigo was subjected to a myelograph and then to a computerized tomographic investigation due to suspect cerebrospinal fluid. The computerized tomography is better than the myelography in diagnosing intraspinal arachnoidal cysts, however this should be preceded by most accurate possible segment location.

  18. Comparison of the practical diagnostic value of different tomographic movements

    International Nuclear Information System (INIS)

    Laehde, S.; Vuoria, P.

    1977-01-01

    The practical results of linear and circular tomography with angles of 6, 20, 30 and 45 degrees and spiral tomography were compared. The spiral proved to be suitable as a tomographic movement for different purposes. In zonography, circular movement with 6 degrees of deviation proved suitable. The linear movement presented no advantages when compared with the multidirectional movements. ( orig.) [de

  19. Computed tomographic findings in manifesting carriers of Duchenne muscular dystrophy

    NARCIS (Netherlands)

    de Visser, M.; Verbeeten, B.

    1985-01-01

    Clinical and computed tomographic (CT) findings in 3 manifesting carriers of Duchenne muscular dystrophy are reported. CT proved to be an important adjunct to the clinical examination: in all our 3 cases a decrease in density was found in various non-paretic muscles

  20. 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

  1. Computerized tomographic findings in children with head trauma in ...

    African Journals Online (AJOL)

    Objective: To describe the computerized tomographic findings in children with head trauma who presented at the University of Benin Teaching Hospital, Benin City, Nigeria. Methods: It is a retrospective review of patients aged 0 – 15 years with suspected intracranial injury (ICI) following head trauma, who presented for CT ...

  2. Pressure spectra from single-snapshot tomographic PIV

    NARCIS (Netherlands)

    Schneiders, J.F.G.; Avallone, F.; Pröbsting, S.; Ragni, D.; Scarano, F.

    2018-01-01

    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

  3. Novel anthropomorphic hip phantom corrects systemic interscanner differences in proximal femoral vBMD

    International Nuclear Information System (INIS)

    Bonaretti, S; Saeed, I; Burghardt, A J; Lang, T; Carpenter, R D; Yu, L; Bruesewitz, M; Khosla, S

    2014-01-01

    Quantitative computed tomography (QCT) is increasingly used in osteoporosis studies to assess volumetric bone mineral density (vBMD), bone quality and strength. However, QCT is confronted by technical issues in the clinical research setting, such as potentially confounding effects of body size on vBMD measurements and lack of standard approaches to scanner cross-calibration, which affects measurements of vBMD in multicenter settings. In this study, we addressed systematic inter-scanner differences and subject-dependent body size errors using a novel anthropomorphic hip phantom, containing a calibration hip to estimate correction equations, and a contralateral test hip to assess the quality of the correction. We scanned this phantom on four different scanners and we applied phantom-derived corrections to in vivo images of 16 postmenopausal women scanned on two scanners. From the phantom study, we found that vBMD decreased with increasing phantom size in three of four scanners and that inter-scanner variations increased with increasing phantom size. In the in vivo study, we observed that inter-scanner corrections reduced systematic inter-scanner mean vBMD differences but that the inter-scanner precision error was still larger than expected from known intra-scanner precision measurements. In conclusion, inter-scanner corrections and body size influence should be considered when measuring vBMD from QCT images. (paper)

  4. ANTHROPOMORPHIC PHANTOMS FOR ASSESSMENT OF STRAIN IMAGING METHODS INVOLVING SALINE-INFUSED SONOHYSTEROGRAPHY

    Science.gov (United States)

    Hobson, Maritza A.; Madsen, Ernest L.; Frank, Gary R.; Jiang, Jingfeng; Shi, Hairong; Hall, Timothy J.; Varghese, Tomy

    2008-01-01

    Two anthropomorphic uterine phantoms were developed which allow assessment and comparison of strain imaging systems adapted for use with saline-infused sonohysterography (SIS). Tissue-mimicking (TM) materials consist of dispersions of safflower oil in gelatin. TM fibroids are stiffer than the TM myometrium/cervix and TM polyps are softer. The first uterine phantom has 3-mm diameter TM fibroids randomly distributed in TM myometrium. The second uterine phantom has a 5-mm and an 8-mm spherical TM fibroid in addition to a 5-mm spherical and a 12.5-mm long (medicine-capsule-shaped) TM endometrial polyp protruding into the endometrial cavity; also, a 10-mm spherical TM fibroid projects from the serosal surface. Strain images using the first phantom show the stiffer 3-mm TM fibroids in the myometrium. Results from the second uterine phantom show that, as expected, parts of inclusions projecting into the uterine cavity will appear very stiff, whether they are stiff or soft. Results from both phantoms show that even though there is a five-fold difference in the Young’s moduli values, there is not a significant difference in the strain in the transition from the TM myometrium to the TM fat. These phantoms allow for realistic comparison and evolution of SIS strain imaging techniques and can aid clinical personnel to develop skills for SIS strain imaging. PMID:18514999

  5. Optimising radiographic bitewing examination to adult and juvenile patients through the use of anthropomorphic phantoms

    International Nuclear Information System (INIS)

    Dauer, L. T.; Branets, I.; Stabulas-Savage, J.; Quinn, B.; Miodownik, D.; Dauer, Z. L.; Colosi, D.; Hershkowitz, D.; Goren, A.

    2014-01-01

    Four anthropomorphic phantoms (an adult male, an adult female, a 10-y-old child and a 5-y-old child) were exposed to bitewing radiographs at film and digital settings using both rectangular and round collimation. Optically stimulated dosemeters were used. For children, average organ doses were <40 μGy and the organs with the highest doses were the salivary glands, parotid, oral mucosa, skin and extrathoracic airway. For adults, average organ doses were <200 μGy. Highest adult doses were to the salivary glands, oral mucosa and skin. Effective doses ranged from 1.5 to 1.8 μSv for children and from 2.6 to 3.6 μSv for adults when optimised technique factors were employed, including digital receptors, rectangular collimation, size-appropriate exposure times and proper clinical judgment. Optimised doses were a fraction of the natural daily background exposure. Therefore, predictions of hypothetical cancer incidence or detriment in patient populations exposed to such low doses are highly speculative and should be discouraged. (authors)

  6. Optimization of a protocol for myocardial perfusion scintigraphy by using an anthropomorphic phantom*

    Science.gov (United States)

    Ramos, Susie Medeiros Oliveira; Glavam, Adriana Pereira; Kubo, Tadeu Takao Almodovar; de Sá, Lidia Vasconcellos

    2014-01-01

    Objective To develop a study aiming at optimizing myocardial perfusion imaging. Materials and Methods Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The 99mTc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. Results The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. Conclusion The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol. PMID:25741088

  7. Beyond intuitive anthropomorphic control: recent achievements using brain computer interface technologies

    Science.gov (United States)

    Pohlmeyer, Eric A.; Fifer, Matthew; Rich, Matthew; Pino, Johnathan; Wester, Brock; Johannes, Matthew; Dohopolski, Chris; Helder, John; D'Angelo, Denise; Beaty, James; Bensmaia, Sliman; McLoughlin, Michael; Tenore, Francesco

    2017-05-01

    Brain-computer interface (BCI) research has progressed rapidly, with BCIs shifting from animal tests to human demonstrations of controlling computer cursors and even advanced prosthetic limbs, the latter having been the goal of the Revolutionizing Prosthetics (RP) program. These achievements now include direct electrical intracortical microstimulation (ICMS) of the brain to provide human BCI users feedback information from the sensors of prosthetic limbs. These successes raise the question of how well people would be able to use BCIs to interact with systems that are not based directly on the body (e.g., prosthetic arms), and how well BCI users could interpret ICMS information from such devices. If paralyzed individuals could use BCIs to effectively interact with such non-anthropomorphic systems, it would offer them numerous new opportunities to control novel assistive devices. Here we explore how well a participant with tetraplegia can detect infrared (IR) sources in the environment using a prosthetic arm mounted camera that encodes IR information via ICMS. We also investigate how well a BCI user could transition from controlling a BCI based on prosthetic arm movements to controlling a flight simulator, a system with different physical dynamics than the arm. In that test, the BCI participant used environmental information encoded via ICMS to identify which of several upcoming flight routes was the best option. For both tasks, the BCI user was able to quickly learn how to interpret the ICMSprovided information to achieve the task goals.

  8. Dose profile study in head CT scans using a male anthropomorphic phantom

    International Nuclear Information System (INIS)

    Gomez, Alvaro M.L.; Santana, Priscila do C.; Mourao, Arnaldo P.

    2017-01-01

    Computed tomography (CT) test is an efficient and non-invasive method to obtain data about internal structures of the human body. CT scans contribute with the highest absorbed doses in population due X-ray beam attenuation and it has raised concern in radiosensitive tissues. Techniques for the optimization of CT scanning protocols in diagnostic services have been developing with the objective of decreasing the absorbed dose in the patient, aiming image quality within acceptable parameters for diagnosis by noise control. Routine head scans were performed using GE CT scan of 64 channels programmed with automatic exposure control and voltages of 80, 100 and 120 kV attaching the noise index in approximately 0.5%, using the tool of smart mA. An anthropomorphic adult male phantom was used and radiochromic film strips were placed to measure the absorbed dose deposited in areas such as the lens, thyroid and pituitary for study of dose deposited in these important areas containing high radiosensitive tissues. Different head scans were performed using optimized values of mA.s for the different voltages. The absorbed dose measured by the film strips were in the range of the 0.58 and 44.36 mGy. The analysis of noise in the images is within the acceptable levels for diagnosis, and the optimized protocol happens with the voltage of 100 kV. The use of other voltage values can allow obtain better protocols for head scans. (author)

  9. Construction of an Anthropomorphic Phantom for Use in Evaluating Pediatric Airway Digital Tomosynthesis Protocols

    Directory of Open Access Journals (Sweden)

    Nima Kasraie

    2018-01-01

    Full Text Available Interpretation of radiolucent foreign bodies (FBs is a common task charged to pediatric radiologists. The use of a motion compensated technique to decrease breathing motion on images would greatly decrease overall exposure to ionizing radiation and increase access to treatment yielding a great impact on clinical care. This study reports on the methodology and materials used to construct an in-house anthropomorphic phantom for investigating image quality in digital tomosynthesis protocols for volumetric imaging of the pediatric airway. Availability and cost of possible substitute materials were considered and simplifying assumptions were made. Two different modular phantoms were assembled in coronal slab layers using materials designed to approximate a one- and three-year-old thorax at diagnostic photon energies for use with digital tomosynthesis protocols such as those offered on GE’s VolumeRAD application. Exposures were made using both phantoms with inserted food particles inside an oscillating airway. The goal of the phantom is to help evaluate (1 whether the currently used protocol is sufficient to image the airway despite breathing motion and (2 whether it is not, to find the optimal protocol by testing various commercially available protocols using this phantom. The affordable construction of the pediatric sized phantom aimed at optimizing GE’s VolumeRAD protocol for airway foreign body imaging is demonstrated in this study which can be used to test VolumeRAD’s ability to image the airways with and without a low-density foreign body within the airways.

  10. Optimization of a protocol for myocardial perfusion scintigraphy by using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Susie Medeiros Oliveira; Sa, Lidia Vasconcellos de, E-mail: susie@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Glavam, Adriana Pereira; Kubo, Tadeu Takao Almodovar [Clinica de Diagnostico Por Imagem (CDPI/DASA), Rio de Janeiro, RJ (Brazil)

    2014-07-15

    Objective: to develop a study aiming at optimizing myocardial perfusion imaging. Materials and Methods: imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The {sup 99m}Tc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. Results: the results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. Conclusion: the described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol. (author)

  11. Estimating effective dose to pediatric patients undergoing interventional radiology procedures using anthropomorphic phantoms and MOSFET dosimeters.

    Science.gov (United States)

    Miksys, Nelson; Gordon, Christopher L; Thomas, Karen; Connolly, Bairbre L

    2010-05-01

    The purpose of this study was to estimate the effective doses received by pediatric patients during interventional radiology procedures and to present those doses in "look-up tables" standardized according to minute of fluoroscopy and frame of digital subtraction angiography (DSA). Organ doses were measured with metal oxide semiconductor field effect transistor (MOSFET) dosimeters inserted within three anthropomorphic phantoms, representing children at ages 1, 5, and 10 years, at locations corresponding to radiosensitive organs. The phantoms were exposed to mock interventional radiology procedures of the head, chest, and abdomen using posteroanterior and lateral geometries, varying magnification, and fluoroscopy or DSA exposures. Effective doses were calculated from organ doses recorded by the MOSFET dosimeters and are presented in look-up tables according to the different age groups. The largest effective dose burden for fluoroscopy was recorded for posteroanterior and lateral abdominal procedures (0.2-1.1 mSv/min of fluoroscopy), whereas procedures of the head resulted in the lowest effective doses (0.02-0.08 mSv/min of fluoroscopy). DSA exposures of the abdomen imparted higher doses (0.02-0.07 mSv/DSA frame) than did those involving the head and chest. Patient doses during interventional procedures vary significantly depending on the type of procedure. User-friendly look-up tables may provide a helpful tool for health care providers in estimating effective doses for an individual procedure.

  12. In vivo proton dosimetry using a MOSFET detector in an anthropomorphic phantom with tissue inhomogeneity.

    Science.gov (United States)

    Kohno, Ryosuke; Hotta, Kenji; Matsubara, Kana; Nishioka, Shie; Matsuura, Taeko; Kawashima, Mitsuhiko

    2012-03-08

    When in vivo proton dosimetry is performed with a metal-oxide semiconductor field-effect transistor (MOSFET) detector, the response of the detector depends strongly on the linear energy transfer. The present study reports a practical method to correct the MOSFET response for linear energy transfer dependence by using a simplified Monte Carlo dose calculation method (SMC). A depth-output curve for a mono-energetic proton beam in polyethylene was measured with the MOSFET detector. This curve was used to calculate MOSFET output distributions with the SMC (SMC(MOSFET)). The SMC(MOSFET) output value at an arbitrary point was compared with the value obtained by the conventional SMC(PPIC), which calculates proton dose distributions by using the depth-dose curve determined by a parallel-plate ionization chamber (PPIC). The ratio of the two values was used to calculate the correction factor of the MOSFET response at an arbitrary point. The dose obtained by the MOSFET detector was determined from the product of the correction factor and the MOSFET raw dose. When in vivo proton dosimetry was performed with the MOSFET detector in an anthropomorphic phantom, the corrected MOSFET doses agreed with the SMC(PPIC) results within the measurement error. To our knowledge, this is the first report of successful in vivo proton dosimetry with a MOSFET detector.

  13. Dose profile study in head CT scans using a male anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Alvaro M.L.; Santana, Priscila do C.; Mourao, Arnaldo P., E-mail: amlgphys@gmail.com, E-mail: pridili@gmail.com, E-mail: apratabhz@gmail.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear; Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil)

    2017-11-01

    Computed tomography (CT) test is an efficient and non-invasive method to obtain data about internal structures of the human body. CT scans contribute with the highest absorbed doses in population due X-ray beam attenuation and it has raised concern in radiosensitive tissues. Techniques for the optimization of CT scanning protocols in diagnostic services have been developing with the objective of decreasing the absorbed dose in the patient, aiming image quality within acceptable parameters for diagnosis by noise control. Routine head scans were performed using GE CT scan of 64 channels programmed with automatic exposure control and voltages of 80, 100 and 120 kV attaching the noise index in approximately 0.5%, using the tool of smart mA. An anthropomorphic adult male phantom was used and radiochromic film strips were placed to measure the absorbed dose deposited in areas such as the lens, thyroid and pituitary for study of dose deposited in these important areas containing high radiosensitive tissues. Different head scans were performed using optimized values of mA.s for the different voltages. The absorbed dose measured by the film strips were in the range of the 0.58 and 44.36 mGy. The analysis of noise in the images is within the acceptable levels for diagnosis, and the optimized protocol happens with the voltage of 100 kV. The use of other voltage values can allow obtain better protocols for head scans. (author)

  14. Calcium scoring with dual-energy CT in men and women: an anthropomorphic phantom study

    Science.gov (United States)

    Li, Qin; Liu, Songtao; Myers, Kyle; Gavrielides, Marios A.; Zeng, Rongping; Sahiner, Berkman; Petrick, Nicholas

    2016-03-01

    This work aimed to quantify and compare the potential impact of gender differences on coronary artery calcium scoring with dual-energy CT. An anthropomorphic thorax phantom with four synthetic heart vessels (diameter 3-4.5 mm: female/male left main and left circumflex artery) were scanned with and without female breast plates. Ten repeat scans were acquired in both single- and dual-energy modes and reconstructed at six reconstruction settings: two slice thicknesses (3 mm, 0.6 mm) and three reconstruction algorithms (FBP, IR3, IR5). Agatston and calcium volume scores were estimated from the reconstructed data using a segmentation-based approach. Total calcium score (summation of four vessels), and male/female calcium scores (summation of male/female vessels scanned in phantom without/with breast plates) were calculated accordingly. Both Agatston and calcium volume scores were found comparable between single- and dual-energy scans (Pearson r= 0.99, pwomen and men in calcium scoring, and for standardizing imaging protocols for improved gender-specific calcium scoring.

  15. Development of anthropomorphic robotic hand driven by Pneumatic Artificial Muscles for robotic applications

    Science.gov (United States)

    Farag, Mohannad; Zainul Azlan, Norsinnira; Hayyan Alsibai, Mohammed

    2018-04-01

    This paper presents the design and fabrication of a three-fingered anthropomorphic robotic hand. The fingers are driven by tendons and actuated by human muscle-like actuators known as Pneumatic Artificial Muscle (PAM). The proposed design allows the actuators to be mounted outside the hand where each finger can be driven by one PAM actuator and six indirectly interlinked tendons. With this design, the three-fingered hand has a compact size and a lightweight with a mass of 150.25 grams imitating the human being hand in terms of size and weight. The hand also successfully grasped objects with different shapes and weights up to 500 g. Even though the number of PAM actuators equals the number of Degrees of Freedom (DOF), the design guarantees driving of three joints by only one actuator reducing the number of required actuators from 3 to 1. Therefore, this hand is suitable for researches of robotic applications in terms of design, cost and ability to be equipped with several types of sensors.

  16. Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

    International Nuclear Information System (INIS)

    Könik, Arda; Johnson, Karen L; Dasari, Paul; Pretorius, P H; Dey, Joyoni; King, Michael A; Connolly, Caitlin M; Segars, Paul W; Lindsay, Clifford

    2014-01-01

    The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used extended cardiac torso (XCAT) phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain a more realistic representation of motion, we developed a series of individual-specific XCAT phantoms, modeling non-rigid respiratory and non-rigid body motions derived from the magnetic resonance imaging (MRI) acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, an MRI was acquired during free/regular breathing. The magnetic resonance slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a graphical user interface. Thus far we have created five body motion and five respiratory motion XCAT phantoms from the MRI acquisitions of six healthy volunteers (three males and three females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory

  17. Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

    Science.gov (United States)

    Könik, Arda; Connolly, Caitlin M.; Johnson, Karen L.; Dasari, Paul; Segars, Paul W.; Pretorius, P. H.; Lindsay, Clifford; Dey, Joyoni; King, Michael A.

    2014-07-01

    The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used extended cardiac torso (XCAT) phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain a more realistic representation of motion, we developed a series of individual-specific XCAT phantoms, modeling non-rigid respiratory and non-rigid body motions derived from the magnetic resonance imaging (MRI) acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, an MRI was acquired during free/regular breathing. The magnetic resonance slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a graphical user interface. Thus far we have created five body motion and five respiratory motion XCAT phantoms from the MRI acquisitions of six healthy volunteers (three males and three females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory

  18. Computation of a voxelized anthropomorphic phantom from Computer Tomography slices and 3D dose distribution calculation utilizing the MCNP5 Code

    International Nuclear Information System (INIS)

    Abella, V.; Miro, R.; Juste, B.; Verdu, G.

    2008-01-01

    Full text: The purpose of this work is to obtain the voxelization of a series of tomography slices in order to provide a voxelized human phantom throughout a MatLab algorithm, and the consequent simulation of the irradiation of such phantom with the photon beam generated in a Theratron 780 (MDS Nordion) 60 Co radiotherapy unit, using the Monte Carlo transport code MCNP (Monte Carlo N-Particle), version 5. The project provides as results dose mapping calculations inside the voxelized anthropomorphic phantom. Prior works have validated the cobalt therapy model utilizing a simple heterogeneous water cube-shaped phantom. The reference phantom model utilized in this work is the Zubal phantom, which consists of a group of pre-segmented CT slices of a human body. The CT slices are to be input into the Matlab program which computes the voxelization by means of two-dimensional pixel and material identification on each slice, and three-dimensional interpolation, in order to depict the phantom geometry via small cubic cells. Each slice is divided in squares with the size of the desired voxelization, and then the program searches for the pixel intensity with a predefined material at each square, making a subsequent three-dimensional interpolation. At the end of this process, the program produces a voxelized phantom in which each voxel defines the mixture of the different materials that compose it. In the case of the Zubal phantom, the voxels result in pure organ materials due to the fact that the phantom is presegmented. The output of this code follows the MCNP input deck format and is integrated in a full input model including the 60 Co radiotherapy unit. Dose rates are calculated using the MCNP5 tool FMESH, superimposed mesh tally. This feature allows to tally particles on an independent mesh over the problem geometry, and to obtain the length estimation of the particle flux, in units of particles/cm 2 (tally F4). Furthermore, the particle flux is transformed into dose by

  19. Software for tomographic analysis: application in ceramic filters

    International Nuclear Information System (INIS)

    Figuerola, W.B.; Assis, J.T.; Oliveira, L.F.; Lopes, R.T.

    2001-01-01

    New methods for acquiring data have been developed with the technological advances. With this, it has been possible to obtain more precise data and, consequently produce results with greater reliability. Among the variety of acquisition methods available, those that have volume description, as CT (Computerized Tomography) and NMR (Nuclear Magnetic Resonance) stand out. The models of volumetric data (group of data that describe a solid object from a three dimensional space) are being greatly used in diversity of areas as a way of inspection, modeling and simulation of objects in a three - dimensional space. Applications of this model are already found in Mechanic Engineering, Geosciences, Medicine and other areas. In the area of engineering it is sometimes necessary to use industrial CT as the only non-invasive form of inspection the interior of pieces without destroying them. The 3D micro focus X-ray tomography is one technique of non destructive testing used in the most different areas of science and technology, given its capacity to generate clean images (practically free of the unhappiness effect) and high resolution reconstructions. The unsharpness effect minimization and space resolution improvement are consequences of the focal spot size reduction in the X-ray micro focus tube to dimensions smaller than 50 mm. The ceramic filters are used in a wide area in the metallurgic industry, particularly in the cast aluminum where they are used to clean the waste coming through the liquid aluminum. The ceramic filters used in this work are manufactured by FUSICO (German company) and they are constructed from foams. They are manufactured at three models: 10, 20 and 30 ppi (porous per inch). In this paper we present the development of software to analyze and characterize ceramic filters, which can be divided in four stages. This software was developed in C++ language, using objects oriented programming. It is also capable of being executed in multiple platforms (Windows

  20. 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)

  1. MO-F-CAMPUS-T-01: IROC Houston QA Center’s Anthropomorphic Proton Phantom Program

    International Nuclear Information System (INIS)

    Lujano, C; Hernandez, N; Keith, T; Nguyen, T; Taylor, P; Molineu, A; Followill, D

    2015-01-01

    Purpose: To describe the proton phantoms that IROC Houston uses to approve and credential proton institutions to participate in NCI-sponsored clinical trials. Methods: Photon phantoms cannot necessarily be used for proton measurements because protons react differently than photons in some plastics. As such plastics that are tissue equivalent for protons were identified. Another required alteration is to ensure that the film dosimeters are housed in the phantom with no air gap to avoid proton streaming. Proton-equivalent plastics/materials used include RMI Solid Water, Techron HPV, blue water, RANDO soft tissue material, balsa wood, compressed cork and polyethylene. Institutions wishing to be approved or credentialed request a phantom and are prioritized for delivery. At the institution, the phantom is imaged, a treatment plan is developed, positioned on the treatment couch and the treatment is delivered. The phantom is returned and the measured dose distributions are compared to the institution’s electronically submitted treatment plan dosimetry data. Results: IROC Houston has developed an extensive proton phantom approval/credentialing program consisting of five different phantoms designs: head, prostate, lung, liver and spine. The phantoms are made with proton equivalent plastics that have HU and relative stopping powers similar (within 5%) of human tissues. They also have imageable targets, avoidance structures, and heterogeneities. TLD and radiochromic film are contained in the target structures. There have been 13 head, 33 prostate, 18 lung, 2 liver and 16 spine irradiations with either passive scatter, or scanned proton beams. The pass rates have been: 100%, 69.7%, 72.2%, 50%, and 81.3%, respectively. Conclusion: IROC Houston has responded to the recent surge in proton facilities by developing a family of anthropomorphic phantoms that are able to be used for remote audits of proton beams. Work supported by PHS grant CA10953 and CA081647

  2. MO-F-CAMPUS-T-01: IROC Houston QA Center’s Anthropomorphic Proton Phantom Program

    Energy Technology Data Exchange (ETDEWEB)

    Lujano, C; Hernandez, N; Keith, T; Nguyen, T; Taylor, P; Molineu, A; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To describe the proton phantoms that IROC Houston uses to approve and credential proton institutions to participate in NCI-sponsored clinical trials. Methods: Photon phantoms cannot necessarily be used for proton measurements because protons react differently than photons in some plastics. As such plastics that are tissue equivalent for protons were identified. Another required alteration is to ensure that the film dosimeters are housed in the phantom with no air gap to avoid proton streaming. Proton-equivalent plastics/materials used include RMI Solid Water, Techron HPV, blue water, RANDO soft tissue material, balsa wood, compressed cork and polyethylene. Institutions wishing to be approved or credentialed request a phantom and are prioritized for delivery. At the institution, the phantom is imaged, a treatment plan is developed, positioned on the treatment couch and the treatment is delivered. The phantom is returned and the measured dose distributions are compared to the institution’s electronically submitted treatment plan dosimetry data. Results: IROC Houston has developed an extensive proton phantom approval/credentialing program consisting of five different phantoms designs: head, prostate, lung, liver and spine. The phantoms are made with proton equivalent plastics that have HU and relative stopping powers similar (within 5%) of human tissues. They also have imageable targets, avoidance structures, and heterogeneities. TLD and radiochromic film are contained in the target structures. There have been 13 head, 33 prostate, 18 lung, 2 liver and 16 spine irradiations with either passive scatter, or scanned proton beams. The pass rates have been: 100%, 69.7%, 72.2%, 50%, and 81.3%, respectively. Conclusion: IROC Houston has responded to the recent surge in proton facilities by developing a family of anthropomorphic phantoms that are able to be used for remote audits of proton beams. Work supported by PHS grant CA10953 and CA081647.

  3. SU-G-TeP2-12: IROCHouston and MDAPL SRS Anthropomorphic Phantom Results

    International Nuclear Information System (INIS)

    Molineu, A; Kry, S; Alvarez, P; Hernandez, N; Nguyen, T; Followill, D

    2016-01-01

    Purpose: To report the results of SRS phantom irradiations Methods: Anthropomorphic SRS head phantoms were sent to institutions participating in NCI sponsored SRS clinical trials and institutions interested in verifying SRS treatment delivery. The phantom shell was purchased from Phantom Laboratory and altered to house dosimetry and imaging inserts. The imaging insert has 1.9 cm diameter spherical target. The dosimetry insert holds two TLD capsules and radiochromic film in the coronal and sagittal planes through the center of the target. Institutions were asked to image, plan and treat the phantom as they would an SRS patient. GammaKnife, CyberKnife and c-arm accelerator institutions were asked to cover the target with 15 Gy, 20 Gy and 25 Gy, respectively. Following these guidelines and typical planning protocols for these three types of machines gives roughly 30 Gy to the center of the target for all units. Submission of the DICOM digital data set was required for analysis. Criteria of 5% for TLD results and 85% of pixels passing 5%/3mm gamma analysis were applied beginning in 2013. Results: The phantom was analyzed 269 times between the beginning of 2013 to present. The pass rate is 81%. Nineteen of the irradiation results failed only the TLD criteria, 19 failed only the film criteria and 12 failed both. Irradiations included 32 CyberKnife 23 GammaKnife, 3 TomoTherapy and 211 c-arm units. Planning systems included Eclipse, Ergo, GammaPlan, Hi-Art, iPlan, Monaco, MultiPlan, Pinnacle, RayStation, XiO and XKnife. Irradiations that were not accompanied with DICOM data were not included in this analysis. Conclusion: The phantom is a valuable end-to-end test used to independently verify the accuracy of SRS treatment delivery. This investigation was supported by IROC grant CA180803 awarded by the NCI.

  4. Advances in development of young-pediatric anthropometric and anthropomorphic head and neck phantoms for dosimetry

    International Nuclear Information System (INIS)

    Thompson, Larissa; Campos, Tarcisio P.R.

    2005-01-01

    The neck malign cancer in pediatric population differs significantly than adult cancer. The pediatric primary malign tumors result in the neck and head fence 5% . The malign cervical tumors, generally, are rabdomyossarcoms and lymphomas. The least frequent malign cancer includes metastasis, scammous cells and thyroid cancer. The larynx cancer treatment is surgery, preferentially. However, lesions with little infiltration, that do not compromise the vocals cords mobile, do not infiltrate cartilage, and do not compromise neither the anterior comissure neither the arytenoid, can be controlled with exclusive radiotherapy. The traditional dose for sub-clinical disease in larynx cancer, neck and head region, has been 50 to 60 Gy to standard fraction of 2 Gy/day, five times for week. When the treatment is consummated with exclusive radiotherapy in primary tumor. The dose must be higher, diversifying from 66 (for small tumors T1) to 70 Gy (for higher tumors, that T2 or T3). Phantoms are simulators utilized for dose prediction in patient simulating radiation interactions with matter. Also it is applied for radio diagnosis equipment calibration and quality control of medical image. Many kind of phantoms are developed, handmade and commercialized, with matters and forms most varied, holding distinct purpose, in senses of establishing double check parameters for reducing planning and calibration errors. This study addresses the development of a object for simulating young-pediatric anthropometric and anthropomorphic head and neck, called phantom, for dosimetric studies. The methodology will be based on the preparation of a phantom respecting the anatomic standards and its tissue equivalent composition. The hope is that phantom can be used in the scientific researches of radiation protocols applied to young-pediatric patient. (author)

  5. Anthropomorphic chest phantom imaging – The potential for dose creep in computed radiography

    International Nuclear Information System (INIS)

    Ma, W.K.; Hogg, P.; Tootell, A.; Manning, D.; Thomas, N.; Kane, T.; Kelly, J.; McKenzie, M.; Kitching, J.

    2013-01-01

    For film-based radiography the operator had to be exact in the selection of acquisition parameters or the image could easily become under- or over-exposed. By contrast, digital technology allows for a much greater tolerance of acquisition factor selection which would still give an image of acceptable diagnostic quality. In turn this greater tolerance allows for the operator to increase effective dose for little or no penalty in image quality. The purpose of this article is to determine how image quality and lesion visibility vary with effective dose (E) in order to identify how much overexposure could be tolerated within the radiograph. Using an anthropomorphic chest phantom with ground glass lesions we determined how perceptual image quality and E varied over a wide range of acquisition conditions. Perceptual image quality comprised of image quality and lesion visibility. E was calculated using Monte Carlo method; image quality was determined using a two alternative forced choice (2AFC) method and the quality criteria were partly informed from European guidelines. Five clinicians with significant experience in image reading scored the images for quality (intraclass correlation coefficient 0.869). Image quality and lesion visibility had a close correlation (R 2 > 0.8). The tolerance for over-exposure, whilst still acquiring an image of acceptable quality, increases with decreasing kV and increasing source to image distance (SID). The maximum over-exposure factor (ratio of maximum E to minimum E that produce images of acceptable quality) possible was 139 (at 125 cm and 60 kV). Given the phantom had characteristics similar to the human thorax we propose that that potential for overexposure in a human whilst still obtaining an image of acceptable perceptual image quality is very high. Further research into overexposure tolerance and dose creep should be undertaken

  6. Computed Tomographic Imaging of Subchondral Fatigue Cracks in the Distal End of the Third Metacarpal Bone in the Thoroughbred Racehorse Can Predict Crack Micromotion in an Ex-Vivo Model

    Science.gov (United States)

    Dubois, Marie-Soleil; Morello, Samantha; Rayment, Kelsey; Markel, Mark D.; Vanderby, Ray; Kalscheur, Vicki L.; Hao, Zhengling; McCabe, Ronald P.; Marquis, Patricia; Muir, Peter

    2014-01-01

    Articular stress fracture arising from the distal end of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at -7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (pThoroughbred horses in-vivo to assess risk of condylar fracture. Horses with parasagittal crack arrays that exceed 30 mm2 may have a high risk for development of condylar fracture. PMID:25077477

  7. Computed tomographic imaging of subchondral fatigue cracks in the distal end of the third metacarpal bone in the thoroughbred racehorse can predict crack micromotion in an ex-vivo model.

    Directory of Open Access Journals (Sweden)

    Marie-Soleil Dubois

    Full Text Available Articular stress fracture arising from the distal end of the third metacarpal bone (MC3 is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at -7,500N (38 condyles, 18 horses. Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (p<0.001. In our biomechanical model, we found a significant positive correlation between extensometer micromotion and parasagittal crack area derived from reconstructed CT images (SR = 0.32, p<0.05. Correlations with transverse and frontal plane crack lengths were not significant. Histologic fatigue damage was not significantly correlated with crack dimensions determined by CT or extensometer micromotion. Bones with parasagittal crack area measurements above 30 mm2 may have a high risk of crack propagation and condylar fracture in vivo because of crack micromotion. In conclusion, our results suggest that CT could be used to quantify subchondral fatigue crack dimensions in racing Thoroughbred horses in-vivo to

  8. 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

  9. 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)

  10. 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

  11. 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.

  12. 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...

  13. Computed tomographic imaging of subchondral fatigue cracks in the distal end of the third metacarpal bone in the thoroughbred racehorse can predict crack micromotion in an ex-vivo model.

    Science.gov (United States)

    Dubois, Marie-Soleil; Morello, Samantha; Rayment, Kelsey; Markel, Mark D; Vanderby, Ray; Kalscheur, Vicki L; Hao, Zhengling; McCabe, Ronald P; Marquis, Patricia; Muir, Peter

    2014-01-01

    Articular stress fracture arising from the distal end of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at -7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (pBones with parasagittal crack area measurements above 30 mm2 may have a high risk of crack propagation and condylar fracture in vivo because of crack micromotion. In conclusion, our results suggest that CT could be used to quantify subchondral fatigue crack dimensions in racing Thoroughbred horses in-vivo to assess risk of condylar fracture. Horses with parasagittal crack arrays that exceed 30 mm2 may have a high risk for development of condylar fracture.

  14. Effect of reconstruction methods and x-ray tube current–time product on nodule detection in an anthropomorphic thorax phantom: A crossed-modality JAFROC observer study

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J. D., E-mail: j.d.thompson@salford.ac.uk [Directorate of Radiography, University of Salford, Frederick Road Campus, Salford, Greater Manchester M6 6PU, United Kingdom and Department of Radiology, Furness General Hospital, University Hospitals of Morecambe Bay NHS Foundation Trust, Dalton Lane, Barrow-in-Furness LA14 4LF (United Kingdom); Chakraborty, D. P. [Department of Radiology, University of Pittsburgh, FARP Building, Room 212, 3362 Fifth Avenue, Pittsburgh, Pennsylvania 15213 (United States); Szczepura, K.; Tootell, A. K. [Directorate of Radiography, University of Salford, Frederick Road Campus, Salford, Greater Manchester M6 6PU (United Kingdom); Vamvakas, I. [Department of Radiology, Christie Hospitals NHS Foundation Trust, 550 Wilmslow Road, Manchester M20 4BX (United Kingdom); Manning, D. J. [Faculty of Health and Medicine, Lancaster Medical School, Furness College, Lancaster University, Lancaster LA1 4YG (United Kingdom); Hogg, P. [Directorate of Radiography, University of Salford, Frederick Road Campus, Salford, Greater Manchester M6 6PU, United Kingdom and Department of Radiography, Karolinksa Institute, Solnavägen 1, Solna 171 77 (Sweden)

    2016-03-15

    Purpose: To evaluate nodule detection in an anthropomorphic chest phantom in computed tomography (CT) images reconstructed with adaptive iterative dose reduction 3D (AIDR{sup 3D}) and filtered back projection (FBP) over a range of tube current–time product (mAs). Methods: Two phantoms were used in this study: (i) an anthropomorphic chest phantom was loaded with spherical simulated nodules of 5, 8, 10, and 12 mm in diameter and +100, −630, and −800 Hounsfield units electron density; this would generate CT images for the observer study; (ii) a whole-body dosimetry verification phantom was used to ultimately estimate effective dose and risk according to the model of the BEIR VII committee. Both phantoms were scanned over a mAs range (10, 20, 30, and 40), while all other acquisition parameters remained constant. Images were reconstructed with both AIDR{sup 3D} and FBP. For the observer study, 34 normal cases (no nodules) and 34 abnormal cases (containing 1–3 nodules, mean 1.35 ± 0.54) were chosen. Eleven observers evaluated images from all mAs and reconstruction methods under the free-response paradigm. A crossed-modality jackknife alternative free-response operating characteristic (JAFROC) analysis method was developed for data analysis, averaging data over the two factors influencing nodule detection in this study: mAs and image reconstruction (AIDR{sup 3D} or FBP). A Bonferroni correction was applied and the threshold for declaring significance was set at 0.025 to maintain the overall probability of Type I error at α = 0.05. Contrast-to-noise (CNR) was also measured for all nodules and evaluated by a linear least squares analysis. Results: For random-reader fixed-case crossed-modality JAFROC analysis, there was no significant difference in nodule detection between AIDR{sup 3D} and FBP when data were averaged over mAs [F(1, 10) = 0.08, p = 0.789]. However, when data were averaged over reconstruction methods, a significant difference was seen between

  15. 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.

  16. Computed tomographic diagnosis of abdominal abscess in childhood

    International Nuclear Information System (INIS)

    Kuhn, J.P.; Berger, P.E.

    1980-01-01

    Twenty-eight children suspected clinically of having an abdominal abscess were examined by CT. Eighteen had gallium 67 citrate scans and 22 had ultrasound studies. Computed tomography was found to be the most accurate test for diagnosis and evaluation of an abscess and the computed tomographic appearance of abscess is illustrated. However, because of cost factors, radiation dose, and clinical considerations, computed tomography is not always the first modality of choice in evaluating a suspected abdominal abscess [fr

  17. 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

  18. Computer tomographic detection of an intraspinal arachnoidal cyst

    International Nuclear Information System (INIS)

    Kuckein, D.; Walter, K.; Paal, G.; Staedtisches Krankenhaus Harlaching, Muenchen

    1981-01-01

    A 46 year old female patient who after 3-4 weeks of influenza suffered from strong headaches, vomiting and rotatory vertigo was subjected to a myelograph and then to a computerized tomographic investigation due to suspect cerebrospinal fluid. The computerized tomography is better than the myelography in diagnosing intraspinal arachnoidal cysts, however this should be preceded by most accurate possible segment location. (MG) [de

  19. 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

  20. Computer tomographic evaluation of digestive tract non-Hodgkin lymphomas.

    Science.gov (United States)

    Lupescu, Ioana G; Grasu, Mugur; Goldis, Gheorghe; Popa, Gelu; Gheorghe, Cristian; Vasilescu, Catalin; Moicean, Andreea; Herlea, Vlad; Georgescu, Serban A

    2007-09-01

    Computer Tomographic (CT) study is crucial for defining distribution, characteristics and staging of primary gastrointestinal lymphomas. The presence of multifocal sites, the wall thickening with diffuse infiltration of the affected gastrointestinal (GI) segment in association with regional adenopathies, permit the orientation of the CT diagnosis for primary GI lymphomas. The gold standard for diagnosis remains, in all cases of digestive tract non-Hodgkin lymphomas (NHL), the histological examination, which allows a tissue diagnosis, performed preferably by transmural biopsy.

  1. An introduction to the tomographic picture of quantum mechanics

    International Nuclear Information System (INIS)

    Ibort, A; Man'ko, V I; Marmo, G; Simoni, A; Ventriglia, F

    2009-01-01

    Starting from the famous Pauli problem on the possibility of associating quantum states with probabilities, the formulation of quantum mechanics in which quantum states are described by fair probability distributions (tomograms, i.e. tomographic probabilities) is reviewed in a pedagogical style. The relation between the quantum state description and the classical state description is elucidated. The difference between those sets of tomograms is described by inequalities equivalent to a complete set of uncertainty relations for the quantum domain and to non-negativity of probability density on phase space in the classical domain. The intersection of such sets is studied. The mathematical mechanism that allows us to construct different kinds of tomographic probabilities like symplectic tomograms, spin tomograms, photon number tomograms, etc is clarified and a connection with abstract Hilbert space properties is established. The superposition rule and uncertainty relations in terms of probabilities as well as quantum basic equations like quantum evolution and energy spectra equations are given in an explicit form. A method to check experimentally the uncertainty relations is suggested using optical tomograms. Entanglement phenomena and the connection with semigroups acting on simplexes are studied in detail for spin states in the case of two-qubits. The star-product formalism is associated with the tomographic probability formulation of quantum mechanics.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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)

  7. Computed Tomographic Analysis of Ventral Atlantoaxial Optimal Safe Implantation Corridors in 27 Dogs.

    Science.gov (United States)

    Leblond, Guillaume; Gaitero, Luis; Moens, Noel M M; Zur Linden, Alex; James, Fiona M K; Monteith, Gabrielle J; Runciman, John

    2017-11-01

    Objectives  Ventral atlantoaxial stabilization techniques are challenging surgical procedures in dogs. Available surgical guidelines are based upon subjective anatomical landmarks, and limited radiographic and computed tomographic data. The aims of this study were (1) to provide detailed anatomical descriptions of atlantoaxial optimal safe implantation corridors to generate objective recommendations for optimal implant placements and (2) to compare anatomical data obtained in non-affected Toy breed dogs, affected Toy breed dogs suffering from atlantoaxial instability and non-affected Beagle dogs. Methods  Anatomical data were collected from a prospectively recruited population of 27 dogs using a previously validated method of optimal safe implantation corridor analysis using computed tomographic images. Results  Optimal implant positions and three-dimensional numerical data were generated successfully in all cases. Anatomical landmarks could be used to generate objective definitions of optimal insertion points which were applicable across all three groups. Overall the geometrical distribution of all implant sites was similar in all three groups with a few exceptions. Clinical Significance  This study provides extensive anatomical data available to facilitate surgical planning of implant placement for atlantoaxial stabilization. Our data suggest that non-affected Toy breed dogs and non-affected Beagle dogs constitute reasonable research models to study atlantoaxial stabilization constructs. Schattauer GmbH Stuttgart.

  8. Investigating the impact of LSO on the count rate of wholebody PET tomographs

    International Nuclear Information System (INIS)

    Douglas, J.L.; Moisan, C.; Rogers, J.G.

    1996-05-01

    We investigated the impact of using detectors made of lutetium oxyorthosilicate (LSO) on the count rate performances of wholebody PET tomographs. To that end, we used a single computational model that predicts the prompt and random contributions to the total event rate in septaless PET tomographs. Dead time factors at all stages of a typical event acquisition stream are calculated from specified values of their respective processing clock cycle. We validated our approach by fitting the true, random and multiple count rates measured with the ECAT-953B and the EXACT HR PLUS scanners for a standard 20 x 20 cm cylindrical phantom. We then investigated the implications of using position encoding detectors made of LSO in the EXACT HR PLUS scanner geometry. The results in indicate that only replacing BGO by the faster LSO incurs no appreciable change in the maximum noise-equivalent-count (NEC) rate of the scanner. However, one could realistically increase the NEC by a factor 2.5 using a 4 nsec coincidence window width with the detector processing front-end operating on a 128 nsec clock cycle. Further reducing the coincidence window width to 600 psec and the front-end clock cycle to 64 nsec leads to an increase of the NEC by a factor 7.5. To sustain the operation of an HR Plus with these specifications, the saturation bandwidth of the data acquisition system would have to be increased to no more than 4.5 MHz. (authors)

  9. 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

  10. 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)

  11. 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

  12. 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)

  13. Total Variation and Tomographic Imaging from Projections

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jørgensen, Jakob Heide

    2011-01-01

    or 3D reconstruction from noisy projections. We demonstrate that for a small signal-to-noise ratio, this new approach allows us to compute better (i.e., more reliable) reconstructions than those obtained by classical methods. This is possible due to the use of the TV reconstruction model, which...

  14. 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)

  15. An anthropomorphic phantom for quality assurance and training in gynaecological brachytherapy

    International Nuclear Information System (INIS)

    Almeida, Carlos Eduardo de; Rodriguez, Miguel; Vianello, Elizabeth; Ferreira, Ivaldo Humberto; Sibata, Claudio

    2002-01-01

    Background and purpose: An anthropomorphic water filled polymethylmethacrylate (PMMA) phantom designed to serve as a Quality Assurance (QA) tool and a training aid in brachytherapy of gynaecological tumours is investigated and presented. Several dosimetric parameters associated with the dose rate calculation can be verified with the aid of this phantom such as the source positioning, its imaging reconstruction from radiographs and the accuracy of the algorithm used for manual or computer dose rate calculation. Material and methods: The phantom walls and the internal structure are 5 mm thick and consist of PMMA, in the form of the abdomen taken from a female Alderson Phantom Marker points representing the organs of interest were determined from computed tomography scans of a patient of similar size. Three PMMA inserts designed to hold a Farmer type ionization chamber of 0.6 cm 3 were positioned at the points to represent the bladder, rectum and point A. The formalism proposed by the IAEA TRS-277 dosimetry protocol was used for the conversion of readings of the ionization chamber to dose rate values with a modification to take into account the dose rate gradient in the detector. Five 137 Cs sources were used and the dose rate was evaluated by measurements and Monte Carlo simulations using the PENELOPE code. Four different treatment planning systems with different algorithms and source reconstruction techniques were also used in this investigation and compared with the manual dose rate calculations made using Karen and Breitman's tables. Results: The dose rate calculations performed with Monte Carlo and the four treatment planning systems are in good agreement with the experimental results as well as with the manual calculations when the colpostat shielding and the tandem attenuation are taken into account. The comparison between experiment and calculations by the four treatment planning systems shows a maximum variation of 5.1% between the calculated and measured

  16. 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.

  17. 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)

  18. Computational voxel phantom, associated to anthropometric and anthropomorphic real phantom for dosimetry in human male pelvis radiotherapy; Fantoma computacional de voxel, associado a fantoma real antropomorfico antropometrico, para dosimetria em radioterapia de pelve masculina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleuza Helena Teixeira; Campos, Tarcisio Passos Ribeiro de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares]. E-mail: campos@nuclear.ufmg.br

    2005-07-01

    This paper addresses a computational model of voxels through MCNP5 Code and the experimental development of an anthropometric and anthropomorphic phantom for dosimetry in human male pelvis brachytherapy focusing prostatic tumors. For elaboration of the computational model of the human male pelvis, anatomical section images from the Visible Man Project were applied. Such selected and digital images were associated to a numeric representation, one for each section. Such computational representation of the anatomical sections was transformed into a bi-dimensional mesh of equivalent tissue. The group of bidimensional meshes was concatenated forming the three-dimensional model of voxels to be used by the MCNP5 code. In association to the anatomical information, data from the density and chemical composition of the basic elements, representatives of the organs and involved tissues, were setup in a material database for the MCNP-5. The model will be applied for dosimetric evaluations in situations of irradiation of the human masculine pelvis. Such 3D model of voxel is associated to the code of transport of particles MCNP5, allowing future simulations. It was also developed the construction of human masculine pelvis phantom, based on anthropometric and anthropomorphic dates and in the use of representative equivalent tissues of the skin, fatty, muscular and glandular tissue, as well as the bony structure.This part of work was developed in stages, being built the bony cast first, later the muscular structures and internal organs. They were then jointly mounted and inserted in the skin cast. The representative component of the fatty tissue was incorporate and accomplished the final retouchings in the skin. The final result represents the development of two important essential tools for elaboration of computational and experimental dosimetry. Thus, it is possible its use in calibrations of pre-existent protocols in radiotherapy, as well as for tests of new protocols, besides

  19. The Study on Radioactive Nuclide Distributions within a Fuel Rod by Tomographic Gamma Scanning Method

    International Nuclear Information System (INIS)

    Quanhu, Zhang; Lee, H. K.; Hong, K. P.; Choo, Y. S.; Kim, D. S.

    2005-06-01

    Based on the specified need of the IMEF, the feasibility of Tomographic Gamma Scanning (TGS) technique has been investigated for its potential for non-destructive gamma scanning measurements of irradiated fuel rods. TGS technique has been developed for determining some radioactive isotopes' distributions of a fuel rod in hot cell. The results obtained from the simulation model extracting from real gamma scanning experimental condition in this work by new developed computer simulation codes confirmed that the gamma emission TGS technique has potential for determination of radioactive isotopes' distributions of a fuel rod. In order to verify the simulation codes, we have designed several computation schemes for both 3 by 3 and 10 by 10 fuel rod model under present situation at M1 hot cell in IMEF. The results which relative errors are less than 10% show that we have simulated and implemented determination of radioactive isotopes' distributions on simulated fuel rod by TGS technique successfully

  20. COMPARISON OF RESPONSE OF PASSIVE DOSIMETRY SYSTEMS IN SCANNING PROTON RADIOTHERAPY-A STUDY USING PAEDIATRIC ANTHROPOMORPHIC PHANTOMS.

    Science.gov (United States)

    Kneževic, Ž; Ambrozova, I; Domingo, C; De Saint-Hubert, M; Majer, M; Martínez-Rovira, I; Miljanic, S; Mojzeszek, N; Porwol, P; Ploc, O; Romero-Expósito, M; Stolarczyk, L; Trinkl, S; Harrison, R M; Olko, P

    2017-11-18

    Proton beam therapy has advantages in comparison to conventional photon radiotherapy due to the physical properties of proton beams (e.g. sharp distal fall off, adjustable range and modulation). In proton therapy, there is the possibility of sparing healthy tissue close to the target volume. This is especially important when tumours are located next to critical organs and while treating cancer in paediatric patients. On the other hand, the interactions of protons with matter result in the production of secondary radiation, mostly neutrons and gamma radiation, which deposit their energy at a distance from the target. The aim of this study was to compare the response of different passive dosimetry systems in mixed radiation field induced by proton pencil beam inside anthropomorphic phantoms representing 5 and 10 years old children. Doses were measured in different organs with thermoluminescent (MTS-7, MTS-6 and MCP-N), radiophotoluminescent (GD-352 M and GD-302M), bubble and poly-allyl-diglycol carbonate (PADC) track detectors. Results show that RPL detectors are the less sensitive for neutrons than LiF TLDs and can be applied for in-phantom dosimetry of gamma component. Neutron doses determined using track detectors, bubble detectors and pairs of MTS-7/MTS-6 are consistent within the uncertainty range. This is the first study dealing with measurements on child anthropomorphic phantoms irradiated by a pencil scanning beam technique. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Dosimetric study of a brachytherapy treatment of esophagus with Brazilian 192Ir sources using an anthropomorphic phantom

    Science.gov (United States)

    Neves, Lucio P.; Santos, William S.; Gorski, Ronan; Perini, Ana P.; Maia, Ana F.; Caldas, Linda V. E.; Orengo, Gilberto

    2014-11-01

    Several radioisotopes are produced at Instituto de Pesquisas Energéticas e Nucleares for the use in medical treatments, including the activation of 192Ir sources. These sources are suitable for brachytherapy treatments, due to their low or high activity, depending on the concentration of 192Ir, easiness to manufacture, small size, stable daughter products and the possibility of re-utilization. They may be used for the treatment of prostate, cervix, head and neck, skin, breast, gallbladder, uterus, vagina, lung, rectum, and eye cancer treatment. In this work, the use of some 192Ir sources was studied for the treatment of esophagus cancer, especially the dose determination of important structures, such as those on the mediastinum. This was carried out utilizing a FASH anthropomorphic phantom and the MCNP5 Monte Carlo code to transport the radiation through matter. It was possible to observe that the doses at lungs, breast, esophagus, thyroid and heart were the highest, which was expected due to their proximity to the source. Therefore, the data are useful to assess the representative dose specific to brachytherapy treatments on the esophagus for radiation protection purposes. The use of brachytherapy sources was studied for the treatment of esophagus cancer. FASH anthropomorphic phantom and MCNP5 Monte Carlo code were employed. The doses at lungs, breast, esophagus, thyroid and heart were the highest. The data is useful to assess the representative doses of treatments on the esophagus.

  2. Application of tomographic inversion in studying airglow in the mesopause region

    Directory of Open Access Journals (Sweden)

    T. Nygrén

    Full Text Available It is pointed out that observations of periodic nightglow structures give excellent information on atmospheric gravity waves in the mesosphere and lower thermosphere. The periods, the horizontal wavelengths and the phase speeds of the waves can be determined from airglow images and, using several cameras, the approximate altitude of the luminous layer can also be determined by triangulation. In this paper the possibility of applying tomographic methods for reconstructing the airglow structures is investigated using numerical simulations. A ground-based chain of cameras is assumed, two-dimensional airglow models in the vertical plane above the chain are constructed, and simulated data are calculated by integrating the models along a great number of rays with different elevation angles for each camera. After addition of random noise, these data are then inverted to obtain reconstructions of the models. A tomographic analysis package originally designed for satellite radiotomography is used in the inversion. The package is based on a formulation of stochastic inversion which allows the input of a priori information to the solver in terms of regularization variances. The reconstruction is carried out in two stages. In the first inversion, constant regularization variances are used within a wide altitude range. The results are used in determining the approximate altitude range of the airglow structures. Then, in the second inversion, constant non-zero regularization variances are used inside this region and zero variances outside it. With this method reliable reconstructions of the models are obtained. The number of cameras as well as their separations are varied in order to find out the limitations of the method.

    Key words. Tomography · Airglow · Mesopause · Gravity waves

  3. Jini service to reconstruct tomographic data

    Science.gov (United States)

    Knoll, Peter; Mirzaei, S.; Koriska, K.; Koehn, H.

    2002-06-01

    A number of imaging systems rely on the reconstruction of a 3- dimensional model from its projections through the process of computed tomography (CT). In medical imaging, for example magnetic resonance imaging (MRI), positron emission tomography (PET), and Single Computer Tomography (SPECT) acquire two-dimensional projections of a three dimensional projections of a three dimensional object. In order to calculate the 3-dimensional representation of the object, i.e. its voxel distribution, several reconstruction algorithms have been developed. Currently, mainly two reconstruct use: the filtered back projection(FBP) and iterative methods. Although the quality of iterative reconstructed SPECT slices is better than that of FBP slices, such iterative algorithms are rarely used for clinical routine studies because of their low availability and increased reconstruction time. We used Jini and a self-developed iterative reconstructions algorithm to design and implement a Jini reconstruction service. With this service, the physician selects the patient study from a database and a Jini client automatically discovers the registered Jini reconstruction services in the department's Intranet. After downloading the proxy object the this Jini service, the SPECT acquisition data are reconstructed. The resulting transaxial slices are visualized using a Jini slice viewer, which can be used for various imaging modalities.

  4. Tomographic pseudo-inversion of resistivity profiles

    Directory of Open Access Journals (Sweden)

    D. Luzio

    1997-06-01

    Full Text Available A new approach to construct vertical and/or horizontal pseudosections starting from sets of resistivity (and/or IP data is presented. In principle it consists in the division of the subsoil into a number of pixels (discretization, arranged in a 3D halfspace. The resistivity of each pixel is then obtained by a back-projection of the set of acquired experimental data, that is by arranging a set of convolutions using 3D filters. The coefficients of the filters are calculated, depending on the geometry of the electrode array used, on the basis of a mask reproducing the «influence coefficients» of all the pixels. The aim of these representations is to match the shape of the investigated structures as close as possible, so that, even if it can be considered a fast arrangement of the experimental data rather than a real inversion, it can be a useful tool in interpretation, at least as a simple preliminary sketch. This method is discussed, focussing on some critical choices regarding the construction of the filters and the use of smoothing factors; some applications on synthetic data calculated on simple models of buried resistive spheres are also presented.

  5. 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.

  6. Computed tomographic study on Mycoplasma pneumoniae pneumonia

    International Nuclear Information System (INIS)

    Tanaka, Hiroshi; Koba, Hiroyuki; Mori, Takuji; Mori, Masaki; Tsunematsu, Kazunori; Natori, Hiroshi; Asakawa, Mitsuo; Suzuki, Akira; Doi, Mikio.

    1985-01-01

    Serologically proven 21 patients with Mycoplasma pneumoniae pneumonia that showed infiltrative shadows on chest radiograms were studied by computed tomography (CT). Localization of the lesion and the fashion of its progression through the lung were analyzed. Following 3 loci were defined on the basis of the investigations of critical analysis of the chest radiograms, and of radiopathological analysis of the experimental animal model of mycoplasmal pneumonia with soft X-ray image. I: Peribronchial and periarterial interstitium. II: Bronchiole and its surroundings. III: Lung parenchyma, on hilar area as IIIh, on marginal area as IIIm. Even in the early phase of this disease, radiopathological findings on CT have been distributed in all loci mentioned above. The Shadow disappeared from locus III approximately 14th day from the onset. The shadow have remained, however, loci I, II for a long period. Those findings suggest that locus I and II are one of the major focus of Mycoplasma neumoniae pneumonia. Volume loss in the locus III was observed 78 % of the cases at 28th day from the onset. The shadow on locus IIIh was more prominent than locus IIIm. Reported analytical method with CT could be widely applied to disclose a radiopathological details in other infectious diseases of the lung. (author)

  7. Phaseless tomographic inverse scattering in Banach spaces

    International Nuclear Information System (INIS)

    Estatico, C.; Fedeli, A.; Pastorino, M.; Randazzo, A.; Tavanti, E.

    2016-01-01

    In conventional microwave imaging, a hidden dielectric object under test is illuminated by microwave incident waves and the field it scatters is measured in magnitude and phase in order to retrieve the dielectric properties by solving the related non-homogenous Helmholtz equation or its Lippmann-Schwinger integral formulation. Since the measurement of the phase of electromagnetic waves can be still considered expensive in real applications, in this paper only the magnitude of the scattering wave fields is measured in order to allow a reduction of the cost of the measurement apparatus. In this respect, we firstly analyse the properties of the phaseless scattering nonlinear forward modelling operator in its integral form and we provide an analytical expression for computing its Fréchet derivative. Then, we propose an inexact Newton method to solve the associated nonlinear inverse problems, where any linearized step is solved by a L p Banach space iterative regularization method which acts on the dual space L p* . Indeed, it is well known that regularization in special Banach spaces, such us L p with 1 < p < 2, allows to promote sparsity and to reduce Gibbs phenomena and over-smoothness. Preliminary results concerning numerically computed field data are shown. (paper)

  8. 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

  9. 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

  10. 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

  11. Neurosurgical operating computerized tomographic scanner system

    International Nuclear Information System (INIS)

    Okudera, Hiroshi; Sugita, Kenichiro; Kobayashi, Shigeaki; Kimishima, Sakae; Yoshida, Hisashi.

    1988-01-01

    A neurosurgical operating computerized tomography scanner system is presented. This system has been developed for obtaining intra- and postoperative CT images in the operating room. A TCT-300 scanner (manufactured by the Toshiba Co., Tokyo) is placed in the operating room. The realization of a true intraoperative CT image requires certain improvements in the CT scanner and operating table. To adjust the axis of the co-ordinates of the motor system of the MST-7000 microsurgical operating table (manufactured by the Mizuho Ika Co., Tokyo) to the CT scanner, we have designed an interface and a precise motor system so that the computer of the CT scanner can directly control the movement of the operating table. Furthermore, a new head-fixation system has been designed for producing artifact-free intraoperative CT images. The head-pins of the head-fixation system are made of carbon-fiber bars and titanium tips. A simulation study of the total system in the operating room with the CT scanner, operating table, and head holder using a skull model yielded a degree of error similar to that in the phantom testing of the original scanner. Three patients underwent resection of a glial tumor using this system. Intraoperative CT scans taken after dural opening showed a bulging of the cortex, a shift in the central structure, and a displacement of the cortical subarachnoid spaces under the influence of gravity. With a contrast medium the edge of the surrounding brain after resection was enhanced and the residual tumor mass was demonstrated clearly. This system makes it possible to obtain a noninvasive intraoperative image in a situation where structural shifts are taking place. (author)

  12. 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.

  13. Tomographic elastography of contracting skeletal muscles from their natural vibrations

    Science.gov (United States)

    Sabra, Karim G.; Archer, Akibi

    2009-11-01

    Conventional elastography techniques require an external mechanical or radiation excitation to measure noninvasively the viscoelastic properties of skeletal muscles and thus monitor human motor functions. We developed instead a passive elastography technique using only an array of skin-mounted accelerometers to record the low-frequency vibrations of the biceps brachii muscle naturally generated during voluntary contractions and to determine their two-dimensional directionality. Cross-correlating these recordings provided travel-times measurements of these muscle vibrations between multiple sensor pairs. Travel-time tomographic inversions yielded spatial variations of their propagation velocity during isometric elbow flexions which indicated a nonuniform longitudinal stiffening of the biceps.

  14. 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.

  15. 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)

  16. 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

  17. Computed tomographic spectrum of intracranial mycosis: correlation with histopathology

    International Nuclear Information System (INIS)

    Whelan, M.A.; Stern, J.; deNapoli, R.A.

    1981-01-01

    Four cases of intracerebral fungal infection are reviewed. The clinical course is outlined, and the computed tomographic (CT) characteristics are analyzed in light of known pathological data. The CT appearance of intracranial mycosis is dependent on the type of fungus as well as the dominant infecting form, i.e., yeast or hyphae. The hyphal form leads predominantly to a CT pattern consistent with vascular occlusion and secondary abscess formation; the yeast form generally results in noncaseating granulomas, which appear on CT scan as nodular enhancing lesions. If the patient survives the acute infective process, these fungal lesions undergo a prolonged subacute phase, and may eventually calcify

  18. Direct computation of harmonic moments for tomographic reconstruction

    International Nuclear Information System (INIS)

    Nara, Takaaki; Ito, Nobutaka; Takamatsu, Tomonori; Sakurai, Tetsuya

    2007-01-01

    A novel algorithm to compute harmonic moments of a density function from its projections is presented for tomographic reconstruction. For projection p(r, θ), we define harmonic moments of projection by ∫ π 0 ∫ ∞ -∞ p(r,θ)(re iθ ) n drd θ and show that it coincides with the harmonic moments of the density function except a constant. Furthermore, we show that the harmonic moment of projection of order n can be exactly computed by using n+ 1 projection directions, which leads to an efficient algorithm to reconstruct the vertices of a polygon from projections.

  19. 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

  20. Non tumoral intracranial expansive processes: clinical tomographic correlation

    International Nuclear Information System (INIS)

    Campos, P.; Herrera, G.; Valneica, F.

    1991-01-01

    Presentation of clinical-tomographic correlation in 111 cases of non tumoral intracranial expansive processes seen between 1984-1988 in the Hospital Cayetano Heredia (Lima, Peru). Emphasis is given fundamentally to: the importance of establishing the organicity of partial and late epilepsy; the high incidence rate of inflammatory infectious processes with CNS compromise in under developing countries; the necessity of making public the importance of two parasitic diseases in the differential diagnosis of non tumoral intracranial expansive processes: free living amebiasis, and toxoplasmosis (especially in association with AIDS). (author)

  1. 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

  2. 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)

  3. 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

  4. A fast tomographic method for searching the minimum free energy path

    International Nuclear Information System (INIS)

    Chen, Changjun; Huang, Yanzhao; Xiao, Yi; Jiang, Xuewei

    2014-01-01

    Minimum Free Energy Path (MFEP) provides a lot of important information about the chemical reactions, like the free energy barrier, the location of the transition state, and the relative stability between reactant and product. With MFEP, one can study the mechanisms of the reaction in an efficient way. Due to a large number of degrees of freedom, searching the MFEP is a very time-consuming process. Here, we present a fast tomographic method to perform the search. Our approach first calculates the free energy surfaces in a sequence of hyperplanes perpendicular to a transition path. Based on an objective function and the free energy gradient, the transition path is optimized in the collective variable space iteratively. Applications of the present method to model systems show that our method is practical. It can be an alternative approach for finding the state-to-state MFEP

  5. Tomographic reconstruction of the time-averaged density distribution in two-phase flow

    International Nuclear Information System (INIS)

    Fincke, J.R.

    1982-01-01

    The technique of reconstructive tomography has been applied to the measurement of time-average density and density distribution in a two-phase flow field. The technique of reconstructive tomography provides a model-independent method of obtaining flow-field density information. A tomographic densitometer system for the measurement of two-phase flow has two unique problems: a limited number of data values and a correspondingly coarse reconstruction grid. These problems were studied both experimentally through the use of prototype hardware on a 3-in. pipe, and analytically through computer generation of simulated data. The prototype data were taken on phantoms constructed of all Plexiglas and Plexiglas laminated with wood and polyurethane foam. Reconstructions obtained from prototype data are compared with reconstructions from the simulated data. Also presented are some representative results in a horizontal air/water flow

  6. 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.

  7. Joint global optimization of tomographic data based on particle swarm optimization and decision theory

    Science.gov (United States)

    Paasche, H.; Tronicke, J.

    2012-04-01

    In many near surface geophysical applications multiple tomographic data sets are routinely acquired to explore subsurface structures and parameters. Linking the model generation process of multi-method geophysical data sets can significantly reduce ambiguities in geophysical data analysis and model interpretation. Most geophysical inversion approaches rely on local search optimization methods used to find an optimal model in the vicinity of a user-given starting model. The final solution may critically depend on the initial model. Alternatively, global optimization (GO) methods have been used to invert geophysical data. They explore the solution space in more detail and determine the optimal model independently from the starting model. Additionally, they can be used to find sets of optimal models allowing a further analysis of model parameter uncertainties. Here we employ particle swarm optimization (PSO) to realize the global optimization of tomographic data. PSO is an emergent methods based on swarm intelligence characterized by fast and robust convergence towards optimal solutions. The fundamental principle of PSO is inspired by nature, since the algorithm mimics the behavior of a flock of birds searching food in a search space. In PSO, a number of particles cruise a multi-dimensional solution space striving to find optimal model solutions explaining the acquired data. The particles communicate their positions and success and direct their movement according to the position of the currently most successful particle of the swarm. The success of a particle, i.e. the quality of the currently found model by a particle, must be uniquely quantifiable to identify the swarm leader. When jointly inverting disparate data sets, the optimization solution has to satisfy multiple optimization objectives, at least one for each data set. Unique determination of the most successful particle currently leading the swarm is not possible. Instead, only statements about the Pareto

  8. The measurement of organic radiation dose of multi-slice CT scanning by using the Chinese anthropomorphic chest phantom

    International Nuclear Information System (INIS)

    Peng Gang; Zeng Yongming; Luo Tianyou; Zhao Feng; Zhang Zhiwei; Yu Renqiang; Peng Shengkun

    2011-01-01

    Objective: Using the Chinese anthropomorphic chest phantom to measure the absorbed dose of various tissues and organs under different noise index, and to assess the radiation dose of MSCT chest scanning with the effective dose (ED). Methods: The equivalence of the Chinese anthropomorphic chest phantom (CDP-1 C) and the adult chest on CT sectional anatomy and X-ray attenuation was demonstrated. The absorbed doses of various tissues and organs under different noise index were measured by laying thermoluminescent dosimeters (TLD) inside the phantom, and the corresponding dose-length products (DLP) were recorded. Both of them were later converted into ED and comparison was conducted to analyze the dose levels of chest CT scanning with automatic tube current modulation (ATCM) under different noise index. Student t-test was applied using SPSS 12.0 statistical software. Results: The Phantom was similar to the human body on CT sectional anatomy. The average CT value of phantom are - 788.04 HU in lung, 45.64 HU in heart, 65.84 HU in liver, 254.32 HU in spine and the deviations are 0.10%, 3.04%, 4.49% and 4.36% respectively compared to humans. The difference of average CT value of liver was statistically significant (t=-8.705, P 0.05). As the noise index increased from 8.5 to 22.5, the DLP decreased from 393.57 mGy · cm to 78.75 mGy · cm and the organs dose declined. For example, the average absorbed dose decreased from 22.38 mGy to 3.66 mGy in lung. Compared to ED calculating by absorbed dose, the ED calculating by DLP was lower. The ED values of the two methods were 6.69 mSv and 8.77 mSv when the noise index was set at 8.5. Conclusions: Application of the Chinese anthropomorphic chest phantom to carry out CT dose assessment is more accurate. The noise index should be set more than 8.5 during the chest CT scanning based on ATCM technique. (authors)

  9. Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy

    Directory of Open Access Journals (Sweden)

    Dana J Lewis

    2014-03-01

    Full Text Available Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC Houston QA Center (formerly RPC.Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS, and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP and Hounsfield unit (HU values. Each material was CT scanned at 120 kVp, and the RSP was obtained from depth ionization scans using the Zebra multi-layer ion chamber (MLIC at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU.Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc., solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%.Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma

  10. Spontaneous Intracerebral Hemorrhage: Computed Tomographic Characteristics and Outcome

    Directory of Open Access Journals (Sweden)

    Aimara de la Caridad Vergara Santos

    2015-12-01

    Full Text Available Background: strokes are the third leading cause of death among adults and 10-15 % of them are due to spontaneous intracerebral hemorrhage. Objective: to characterize spontaneous intracerebral hemorrhage through computed tomography scan and its outcome. Methods: a case series study was conducted comprising patients diagnosed with spontaneous intracerebral hemorrhage admitted to the Arnaldo Milián Castro Provincial University Hospital in Villa Clara from January 2009 to January 2010. Tomographic variables of interest were derived from evaluation of spontaneous intracerebral hematomas. Results: fifty-nine cases of spontaneous intracerebral hemorrhage were studied, 23 were located in lobar regions, 4 had severe midline shift, and 2 showed volume greater than 80 ml. Eight out of eleven with extension into the ventricular system had an unfavorable outcome. Among those with thalamic hemorrhage, patients with diameter larger than 4cm and extension into the ventricular system died. Patients with putaminal hemorrhage larger than 4 cm and posterior fossa hematoma with hydrocephalus had a poor outcome, as well as most individuals (55 with other mass effects. Most lobar hematomas (14 out of 23 had a satisfactory outcome, unlike cerebellar and brainstem hematomas. Conclusions: tomographic variables that had a negative impact on the outcome were: volume greater than 80 ml, severe midline shift, diameter larger than 4 cm, extension into the ventricular system, hydrocephalus, other signs of mass effect and brainstem location.

  11. Clinical findings in 16 patients with tomographic diagnosis of schizencephaly

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Maria do Carmo de Souza [Universidade Federal do Espirito Santo, Vitoria, ES (Brazil). Hospital Universitario Cassiano Antonio Moraes]. E-mail: rodriguesmcs@yahoo.com.br; Monteiro, Alexandra Maria Vieira [Universidade do Estado do Rio de Janeiro, RJ (Brazil). Faculdade de Ciencias Medicas; Llerena Junior, Juan Clinton [Fundacao Oswaldo Cruz, Rio de Janeiro, RJ (Brazil). Instituto Fernandes Figueira. Centro de Genetica Medica; Fernandes, Alexandre Ribeiro [Universidade Gama Filho, Rio de Janeiro, RJ (Brazil). Dept. de Pediatria

    2006-09-15

    Objective: to establish a correlation between clinical features in a group of children with tomographic diagnosis of schizencephaly and clefts extent and localization. Materials and methods: retrospective study of dossiers from the archives of Neurology and Medical Genetics Services at Instituto Fernandes Figueira/FIOCRUZ and Hospital Municipal Jesus, Rio de Janeiro, RJ, Brazil, in the period between 2000 and 2003. The study included 16 patients, nine female and seven male, with tomographic diagnosis of schizencephaly investigated for clinical findings, psychomotor development, motor/cognitive deficits and epilepsy. Results: predominance of bilateral clefts in 10:16 patients, open-lip schizencephaly type in 23:27 patients, and small lips in 11:27 patients. As regards anomalies associated with schizencephaly, pellucid septum absence was the most frequent one (10:16 patients). As regards clinical findings, 15 patients presented with developmental delay and motor deficit, six patients with cognitive deficit and ten with epilepsy. In three patients, we observed discordant clinical findings and cleft sizes, although the clefts were small, the clinical features severity was high because of other cerebral anomalies. Conclusion: the clinical features of schizencephaly are related to the size of the clefts, regardless laterality, presenting higher severity when associated with other cerebral anomalies. (author)

  12. Tomographic reconstruction of OH* chemiluminescence in two interacting turbulent flames

    International Nuclear Information System (INIS)

    Worth, Nicholas A; Dawson, James R

    2013-01-01

    The tomographic reconstruction of OH* chemiluminescence was performed on two interacting turbulent premixed bluff-body stabilized flames under steady flow conditions and acoustic excitation. These measurements elucidate the complex three-dimensional (3D) vortex–flame interactions which have previously not been accessible. The experiment was performed using a single camera and intensifier, with multiple views acquired by repositioning the camera, permitting calculation of the mean and phase-averaged volumetric OH* distributions. The reconstructed flame structure and phase-averaged dynamics are compared with OH planar laser-induced fluorescence and flame surface density measurements for the first time. The volumetric data revealed that the large-scale vortex–flame structures formed along the shear layers of each flame collide when the two flames meet, resulting in complex 3D flame structures in between the two flames. With a fairly simple experimental setup, it is shown that the tomographic reconstruction of OH* chemiluminescence in forced flames is a powerful tool that can yield important physical insights into large-scale 3D flame dynamics that are important in combustion instability. (paper)

  13. 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)

  14. Clinical findings in 16 patients with tomographic diagnosis of schizencephaly

    International Nuclear Information System (INIS)

    Rodrigues, Maria do Carmo de Souza; Monteiro, Alexandra Maria Vieira; Llerena Junior, Juan Clinton; Fernandes, Alexandre Ribeiro

    2006-01-01

    Objective: to establish a correlation between clinical features in a group of children with tomographic diagnosis of schizencephaly and clefts extent and localization. Materials and methods: retrospective study of dossiers from the archives of Neurology and Medical Genetics Services at Instituto Fernandes Figueira/FIOCRUZ and Hospital Municipal Jesus, Rio de Janeiro, RJ, Brazil, in the period between 2000 and 2003. The study included 16 patients, nine female and seven male, with tomographic diagnosis of schizencephaly investigated for clinical findings, psychomotor development, motor/cognitive deficits and epilepsy. Results: predominance of bilateral clefts in 10:16 patients, open-lip schizencephaly type in 23:27 patients, and small lips in 11:27 patients. As regards anomalies associated with schizencephaly, pellucid septum absence was the most frequent one (10:16 patients). As regards clinical findings, 15 patients presented with developmental delay and motor deficit, six patients with cognitive deficit and ten with epilepsy. In three patients, we observed discordant clinical findings and cleft sizes, although the clefts were small, the clinical features severity was high because of other cerebral anomalies. Conclusion: the clinical features of schizencephaly are related to the size of the clefts, regardless laterality, presenting higher severity when associated with other cerebral anomalies. (author)

  15. 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.

  16. 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.; Uber, D.; Vuletich, T.; Budinger, T.F.

    1986-10-01

    We describe a positron tomograph using a single ring of 600 close-packed 3 mm wide bismuth germanate (BGO) crystals coupled to 14 mm phototubes. The phototube preamplifier circuit derives a timing pulse from the first photoelectron, and sends it to address and coincidence circuits only if the integrated pulse height is within a pre-set window. The timing delays and pulse height windows for all 600 detectors and the coincidence timing windows are computer adjustable. An orbiting positron source is used for transmission measurements and a look-up table is used to reject scattered and random coincidences that do not pass through the source. Data can be acquired using a stationary mode for 1.57 mm lateral sampling or the two-position clam sampling mode for 0.79 mm lateral sampling. High maximum data rates are provided by 45 parallel coincidence circuits and 4 parallel histogram memory units. With two-position sampling and 1.57 mm bins, the reconstructed point spread function (PSF) of a 0.35 mm diam 22 Na wire source at the center of the tomograph is circular with 2.9 mm full-width at half-maximum (fwhm) and the PSF at a distance of 8 cm from the center is elliptical with a radial fwhm of 4.0 mm and tangential fwhm of 3.0 mm. 12 refs., 6 figs., 3 tabs

  17. 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

  18. Tomographic Constraints on High-Energy Neutrinos of Hadronuclear Origin.

    Science.gov (United States)

    Ando, Shin'ichiro; Tamborra, Irene; Zandanel, Fabio

    2015-11-27

    Mounting evidence suggests that the TeV-PeV neutrino flux detected by the IceCube telescope has mainly an extragalactic origin. If such neutrinos are primarily produced by a single class of astrophysical sources via hadronuclear (pp) interactions, a similar flux of gamma-ray photons is expected. For the first time, we employ tomographic constraints to pinpoint the origin of the IceCube neutrino events by analyzing recent measurements of the cross correlation between the distribution of GeV gamma rays, detected by the Fermi satellite, and several galaxy catalogs in different redshift ranges. We find that the corresponding bounds on the neutrino luminosity density are up to 1 order of magnitude tighter than those obtained by using only the spectrum of the gamma-ray background, especially for sources with mild redshift evolution. In particular, our method excludes any hadronuclear source with a spectrum softer than E^{-2.1} as a main component of the neutrino background, if its evolution is slower than (1+z)^{3}. Starburst galaxies, if able to accelerate and confine cosmic rays efficiently, satisfy both spectral and tomographic constraints.

  19. Tomographic Environmental Sections for Environmental Mitigation Devices in Historical Centers

    Directory of Open Access Journals (Sweden)

    Roberta Cocci Grifoni

    2017-03-01

    Full Text Available Urban heat waves and the overall growing trend in the annual global temperature underline the importance of urban/architectural resilience and the need to reduce energy consumption. By designing urban voids, it is possible to create thermodynamic buffers, i.e., bubbles of controlled atmosphere that act as mediators between the natural and built environments, between the human body and the surrounding air, between meteorology and physiology (meteorological architecture. Multiple small actions in the urban fabric’s open spaces, such as replacing dark pavements or inserting vegetation and green spaces, are intended to improve outdoor comfort conditions and therefore the resilience of the city itself. This not only benefits the place’s quality, which is intrinsic to the new project, but also the insulating capacity of buildings, which are relieved of an external heat load. The design emphasis therefore changes from solid structures to the climate and weather conditions, which are invisible but perceivable. To design and control these constructed atmopheres, tomographic sections processed with computational fluid dynamics software (tomographic environmental section, TENS becomes necessary. It allows the effects of an extreme event on an outdoor environment to be evaluated in order to establish the appropriate (adaptive climate mitigation devices, especially in historical centers where energy retrofits are often discouraged. By fixing boundary conditions after a local intervention, the virtual environment can be simulated and then "sliced" to analyze initial values and verify the design improvements.

  20. 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

  1. On the estimation of wall pressure coherence using time-resolved tomographic PIV

    Science.gov (United States)

    Pröbsting, Stefan; Scarano, Fulvio; Bernardini, Matteo; Pirozzoli, Sergio

    2013-07-01

    Three-dimensional time-resolved velocity field measurements are obtained using a high-speed tomographic Particle Image Velocimetry (PIV) system on a fully developed flat plate turbulent boundary layer for the estimation of wall pressure fluctuations. The work focuses on the applicability of tomographic PIV to compute the coherence of pressure fluctuations, with attention to the estimation of the stream and spanwise coherence length. The latter is required for estimations of aeroacoustic noise radiation by boundary layers and trailing edge flows, but is also of interest for vibro-structural problems. The pressure field is obtained by solving the Poisson equation for incompressible flows, where the source terms are provided by time-resolved velocity field measurements. Measured 3D velocity data is compared to results obtained from planar PIV, and a Direct Numerical Simulation (DNS) at similar Reynolds number. An improved method for the estimation of the material based on a least squares estimator of the velocity derivative along a particle trajectory is proposed and applied. Computed surface pressure fluctuations are further verified by means of simultaneous measurements by a pinhole microphone and compared to the DNS results and a semi-empirical model available from literature. The correlation coefficient for the reconstructed pressure time series with respect to pinhole microphone measurements attains approximately 0.5 for the band-pass filtered signal over the range of frequencies resolved by the velocity field measurements. Scaled power spectra of the pressure at a single point compare favorably to the DNS results and those available from literature. Finally, the coherence of surface pressure fluctuations and the resulting span- and streamwise coherence lengths are estimated and compared to semi-empirical models and DNS results.

  2. Effects of megavoltage computed tomographic scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy.

    Science.gov (United States)

    Zhu, Jian; Bai, Tong; Gu, Jiabing; Sun, Ziwen; Wei, Yumei; Li, Baosheng; Yin, Yong

    2018-04-27

    To evaluate the effect of pretreatment megavoltage computed tomographic (MVCT) scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy. Both anthropomorphic heterogeneous chest and pelvic phantoms were planned with virtual targets by TomoTherapy Physicist Station and were scanned with TomoTherapy megavoltage image-guided radiotherapy (IGRT) system consisted of six groups of options: three different acquisition pitches (APs) of 'fine', 'normal' and 'coarse' were implemented by multiplying 2 different corresponding reconstruction intervals (RIs). In order to mimic patient setup variations, each phantom was shifted 5 mm away manually in three orthogonal directions respectively. The effect of MVCT scan options was analyzed in image quality (CT number and noise), adaptive dose calculation deviations and positional correction variations. MVCT scanning time with pitch of 'fine' was approximately twice of 'normal' and 3 times more than 'coarse' setting, all which will not be affected by different RIs. MVCT with different APs delivered almost identical CT numbers and image noise inside 7 selected regions with various densities. DVH curves from adaptive dose calculation with serial MVCT images acquired by varied pitches overlapped together, where as there are no significant difference in all p values of intercept & slope of emulational spinal cord (p = 0.761 & 0.277), heart (p = 0.984 & 0.978), lungs (p = 0.992 & 0.980), soft tissue (p = 0.319 & 0.951) and bony structures (p = 0.960 & 0.929) between the most elaborated and the roughest serials of MVCT. Furthermore, gamma index analysis shown that, compared to the dose distribution calculated on MVCT of 'fine', only 0.2% or 1.1% of the points analyzed on MVCT of 'normal' or 'coarse' do not meet the defined gamma criterion. On chest phantom, all registration errors larger than 1 mm appeared at superior-inferior axis, which cannot be avoided with the smallest AP and RI

  3. Use of Anthropomorphic Brand Mascots for Student Motivation and Engagement: A Promotional Case Study with Pablo the Penguin at the University of Portsmouth Library

    Science.gov (United States)

    Bennett, David E.; Thompson, Paula

    2016-01-01

    A case study demonstrating how an online narrative featuring the adventures of a cuddly toy penguin, Pablo Penguin (@uoppenguin on Twitter) has been introduced at the University of Portsmouth Library to build trust and engagement between university students and library services and facilities. Evidence for the benefits of anthropomorphic brand…

  4. Sensitivity and accuracy of volumetry of pulmonary nodules on low-dose 16- and 64-row multi-detector CT : an anthropomorphic phantom study

    NARCIS (Netherlands)

    Xie, X.; Zhao, Yingru; Snijder, R.A.; van Ooijen, P.M.; de Jong, P.A.; Oudkerk, M.; de Bock, G.H.; Vliegenthart, R.; Greuter, M.J.

    To assess the sensitivity of detection and accuracy of volumetry by manual and semi-automated quantification of artificial pulmonary nodules in an anthropomorphic thoracic phantom on low-dose CT. Fifteen artificial spherical nodules (diameter 3, 5, 8, 10 and 12 mm; CT densities -800, -630 and +100

  5. 75 FR 76636 - Anthropomorphic Test Devices; Hybrid III 6-Year-Old Child Test Dummy, Hybrid III 6-Year-Old...

    Science.gov (United States)

    2010-12-09

    ... provision: ``When a motor vehicle safety standard is in effect under this chapter, a State or a political... [Docket No. NHTSA-2010-0147] RIN 2127-AK34 Anthropomorphic Test Devices; Hybrid III 6-Year-Old Child Test Dummy, Hybrid III 6-Year-Old Weighted Child Test Dummy AGENCY: National Highway Traffic Safety...

  6. Analysis of the features of untrained human movements based on the multichannel EEG for controlling anthropomorphic robotic arm

    Science.gov (United States)

    Maksimenko, Vladimir; Runnova, Anastasia; Pchelintseva, Svetlana; Efremova, Tatiana; Zhuravlev, Maksim; Pisarchik, Alexander

    2018-04-01

    We have considered time-frequency and spatio-temporal structure of electrical brain activity, associated with real and imaginary movements based on the multichannel EEG recordings. We have found that along with wellknown effects of event-related desynchronization (ERD) in α/μ - rhythms and β - rhythm, these types of activity are accompanied by the either ERS (for real movement) or ERD (for imaginary movement) in low-frequency δ - band, located mostly in frontal lobe. This may be caused by the associated processes of decision making, which take place when subject is deciding either perform the movement or imagine it. Obtained features have been found in untrained subject which it its turn gives the possibility to use our results in the development of brain-computer interfaces for controlling anthropomorphic robotic arm.

  7. An Optimal Design of Driving Mechanism in a 1 Degree of Freedom (d.o.f. Anthropomorphic Finger

    Directory of Open Access Journals (Sweden)

    M. Ceccarelli

    2005-01-01

    Full Text Available Mechanisms can be used in finger design to obtain suitable actuation systems and to give stiff robust behavior in grasping tasks. The design of driving mechanisms for fingers has been attached at LARM in Cassino with the aim to obtain one degree of freedom actuation for an anthropomorphic finger. The dimensional design of a finger-driving mechanism has been formulated as a multi-objective optimization problem by using evaluation criteria for fundamental characteristics regarding with finger motion, grasping equilibrium and force transmission. The feasibility of the herein proposed optimum design procedure for a finger-driving mechanism has been tested by numerical examples that have been also used to enhance a prototype previously built at LARM in Cassino.

  8. Design of a multimodal ({sup 1}H/{sup 23}Na MR/CT) anthropomorphic thorax phantom

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Wiebke; Lietzmann, Florian; Schad, Lothar R.; Zoellner, Frank G. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine

    2017-08-01

    This work proposes a modular, anthropomorphic MR and CT thorax phantom that enables the comparison of experimental studies for quantitative evaluation of deformable, multimodal image registration algorithms and realistic multi-nuclear MR imaging techniques. A human thorax phantom was developed with insertable modules representing lung, liver, ribs and additional tracking spheres. The quality of human tissue mimicking characteristics was evaluated for {sup 1}H and {sup 23}Na MR as well as CT imaging. The position of landmarks in the lung lobes was tracked during CT image acquisition at several positions during breathing cycles. {sup 1}H MR measurements of the liver were repeated after seven months to determine long term stability. The modules possess HU, T{sub 1} and T{sub 2} values comparable to human tissues (lung module: -756 ± 148 HU, artificial ribs: 218 ± 56 HU (low CaCO{sub 3} concentration) and 339 ± 121 (high CaCO{sub 3} concentration), liver module: T{sub 1} = 790 ± 28 ms, T{sub 2} = 65 ± 1 ms). Motion analysis showed that the landmarks in the lung lobes follow a 3D trajectory similar to human breathing motion. The tracking spheres are well detectable in both CT and MRI. The parameters of the tracking spheres can be adjusted in the following ranges to result in a distinct signal: HU values from 150 to 900 HU, T{sub 1} relaxation time from 550 ms to 2000 ms, T{sub 2} relaxation time from 40 ms to 200 ms. The presented anthropomorphic multimodal thorax phantom fulfills the demands of a simple, inexpensive system with interchangeable components. In future, the modular design allows for complementing the present set up with additional modules focusing on specific research targets such as perfusion studies, {sup 23}Na MR quantification experiments and an increasing level of complexity for motion studies.

  9. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    Science.gov (United States)

    Oancea, C.; Shipulin, K.; Mytsin, G.; Molokanov, A.; Niculae, D.; Ambrožová, I.; Davídková, M.

    2017-03-01

    A dosimetric experiment was performed at the Medico-Technical Complex in the Joint Institute for Nuclear Research, Dubna, to investigate the effects of metallic dental implants in the treatment of head and neck tumours with proton therapy. The goal of the study was to evaluate the 2D dose distributions of different clinical treatment plans measured in an anthropomorphic phantom, and compare them to predictions from a treatment planning system. The anthropomorphic phantom was sliced into horizontal segments. Two grade 4 Titanium implants were inserted between 2 slices, corresponding to a maxillary area. GafChromic EBT2 films were placed between the segments containing the implants to measure the 2D delivered dose. Two different targets were designed: the first target includes the dental implants in the isocentre, and in the second target, the proton beam is delivered through the implants, which are located at the entrance region of the Bragg curve. The experimental results were compared to the treatment plans made using our custom 3D Treatment Planning System, named RayTreat. To quantitatively determine differences in the isodose distributions (measured and calculated), the gamma index (3 mm, 3%) was calculated for each target for the matrix value in the region of high isodose (> 90%): for the experimental setup, which includes the implants in the SOBP region, the result obtained was 84.3%. When the implants were localised in the entrance region of the Bragg curve, the result obtained was 86.4%. In conclusion, the uncertainties introduced by the clinically planned dose distribution are beyond reasonable limits. The linear energy transfer spectra in close proximity to the implants were investigated using solid state nuclear track detectors (TED). Scattered particles outside the target were detected.

  10. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    International Nuclear Information System (INIS)

    Oancea, C.; Shipulin, K.; Mytsin, G.; Molokanov, A.; Niculae, D.; Ambrožová, I.; Davídková, M.

    2017-01-01

    A dosimetric experiment was performed at the Medico-Technical Complex in the Joint Institute for Nuclear Research, Dubna, to investigate the effects of metallic dental implants in the treatment of head and neck tumours with proton therapy. The goal of the study was to evaluate the 2D dose distributions of different clinical treatment plans measured in an anthropomorphic phantom, and compare them to predictions from a treatment planning system. The anthropomorphic phantom was sliced into horizontal segments. Two grade 4 Titanium implants were inserted between 2 slices, corresponding to a maxillary area. GafChromic EBT2 films were placed between the segments containing the implants to measure the 2D delivered dose. Two different targets were designed: the first target includes the dental implants in the isocentre, and in the second target, the proton beam is delivered through the implants, which are located at the entrance region of the Bragg curve. The experimental results were compared to the treatment plans made using our custom 3D Treatment Planning System, named RayTreat. To quantitatively determine differences in the isodose distributions (measured and calculated), the gamma index (3 mm, 3%) was calculated for each target for the matrix value in the region of high isodose (> 90%): for the experimental setup, which includes the implants in the SOBP region, the result obtained was 84.3%. When the implants were localised in the entrance region of the Bragg curve, the result obtained was 86.4%. In conclusion, the uncertainties introduced by the clinically planned dose distribution are beyond reasonable limits. The linear energy transfer spectra in close proximity to the implants were investigated using solid state nuclear track detectors (TED). Scattered particles outside the target were detected.

  11. Inter- and intrascanner variability of pulmonary nodule volumetry on low-dose 64-row CT: an anthropomorphic phantom study

    Science.gov (United States)

    Xie, X; Willemink, M J; Zhao, Y; de Jong, P A; van Ooijen, P M A; Oudkerk, M; Greuter, M J W

    2013-01-01

    Objective: To assess inter- and intrascanner variability in volumetry of solid pulmonary nodules in an anthropomorphic thoracic phantom using low-dose CT. Methods: Five spherical solid artificial nodules [diameters 3, 5, 8, 10 and 12 mm; CT density +100 Hounsfield units (HU)] were randomly placed inside an anthropomorphic thoracic phantom in different combinations. The phantom was examined on two 64-row multidetector CT (64-MDCT) systems (CT-A and CT-B) from different vendors with a low-dose protocol. Each CT examination was performed three times. The CT examinations were evaluated twice by independent blinded observers. Nodule volume was semi-automatically measured by dedicated software. Interscanner variability was evaluated by Bland–Altman analysis and expressed as 95% confidence interval (CI) of relative differences. Intrascanner variability was expressed as 95% CI of relative variation from the mean. Results: No significant difference in CT-derived volume was found between CT-A and CT-B, except for the 3-mm nodules (pvolumetry of artificial pulmonary nodules between 5 mm and 12 mm in diameter. Inter- and intrascanner variability decreases at a larger nodule size to a maximum of 4.9% for ≥8 mm nodules. Advances in knowledge: The commonly accepted cut-off of 25% to determine nodule growth has the potential to be reduced for ≥8 mm nodules. This offers the possibility of reducing the interval for repeated CT scans in lung cancer screenings. PMID:23884758

  12. Prediction of Clinical Outcome After Acute Ischemic Stroke: The Value of Repeated Noncontrast Computed Tomography, Computed Tomographic Angiography, and Computed Tomographic Perfusion.

    Science.gov (United States)

    Dankbaar, Jan W; Horsch, Alexander D; van den Hoven, Andor F; Kappelle, L Jaap; van der Schaaf, Irene C; van Seeters, Tom; Velthuis, Birgitta K

    2017-09-01

    Early prediction of outcome in acute ischemic stroke is important for clinical management. This study aimed to compare the relationship between early follow-up multimodality computed tomographic (CT) imaging and clinical outcome at 90 days in a large multicenter stroke study. From the DUST study (Dutch Acute Stroke Study), patients were selected with (1) anterior circulation occlusion on CT angiography (CTA) and ischemic deficit on CT perfusion (CTP) on admission, and (2) day 3 follow-up noncontrast CT, CTP, and CTA. Follow-up infarct volume on noncontrast CT, poor recanalization on CTA, and poor reperfusion on CTP (mean transit time index ≤75%) were related to unfavorable outcome after 90 days defined as modified Rankin Scale 3 to 6. Four multivariable models were constructed: (1) only baseline variables (model 1), (2) model 1 with addition of infarct volume, (3) model 1 with addition of recanalization, and (4) model 1 with addition of reperfusion. Area under the curves of the receiver operating characteristic curves of the models were compared using the DeLong test. A total of 242 patients were included. Poor recanalization was found in 21%, poor reperfusion in 37%, and unfavorable outcome in 44%. The area under the curve of the receiver operating characteristic curve without follow-up imaging was 0.81, with follow-up noncontrast CT 0.85 ( P =0.02), CTA 0.86 ( P =0.01), and CTP 0.86 ( P =0.01). All 3 follow-up imaging modalities improved outcome prediction compared with no imaging. There was no difference between the imaging models. Follow-up imaging after 3 days improves outcome prediction compared with prediction based on baseline variables alone. CTA recanalization and CTP reperfusion do not outperform noncontrast CT at this time point. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00880113. © 2017 American Heart Association, Inc.

  13. Relationship of Hypertension to Coronary Atherosclerosis and Cardiac Events in Patients With Coronary Computed Tomographic Angiography.

    Science.gov (United States)

    Nakanishi, Rine; Baskaran, Lohendran; Gransar, Heidi; Budoff, Matthew J; Achenbach, Stephan; Al-Mallah, Mouaz; Cademartiri, Filippo; Callister, Tracy Q; Chang, Hyuk-Jae; Chinnaiyan, Kavitha; Chow, Benjamin J W; DeLago, Augustin; Hadamitzky, Martin; Hausleiter, Joerg; Cury, Ricardo; Feuchtner, Gudrun; Kim, Yong-Jin; Leipsic, Jonathon; Kaufmann, Philipp A; Maffei, Erica; Raff, Gilbert; Shaw, Leslee J; Villines, Todd C; Dunning, Allison; Marques, Hugo; Pontone, Gianluca; Andreini, Daniele; Rubinshtein, Ronen; Bax, Jeroen; Jones, Erica; Hindoyan, Niree; Gomez, Millie; Lin, Fay Y; Min, James K; Berman, Daniel S

    2017-08-01

    Hypertension is an atherosclerosis factor and is associated with cardiovascular risk. We investigated the relationship between hypertension and the presence, extent, and severity of coronary atherosclerosis in coronary computed tomographic angiography and cardiac events risk. Of 17 181 patients enrolled in the CONFIRM registry (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry) who underwent ≥64-detector row coronary computed tomographic angiography, we identified 14 803 patients without known coronary artery disease. Of these, 1434 hypertensive patients were matched to 1434 patients without hypertension. Major adverse cardiac events risk of hypertension and non-hypertensive patients was evaluated with Cox proportional hazards models. The prognostic associations between hypertension and no-hypertension with increasing degree of coronary stenosis severity (nonobstructive or obstructive ≥50%) and extent of coronary artery disease (segment involvement score of 1-5, >5) was also assessed. Hypertension patients less commonly had no coronary atherosclerosis and more commonly had nonobstructive and 1-, 2-, and 3-vessel disease than the no-hypertension group. During a mean follow-up of 5.2±1.2 years, 180 patients experienced cardiac events, with 104 (2.0%) occurring in the hypertension group and 76 (1.5%) occurring in the no-hypertension group (hazard ratios, 1.4; 95% confidence intervals, 1.0-1.9). Compared with no-hypertension patients without coronary atherosclerosis, hypertension patients with no coronary atherosclerosis and obstructive coronary disease tended to have higher risk of cardiac events. Similar trends were observed with respect to extent of coronary artery disease. Compared with no-hypertension patients, hypertensive patients have increased presence, extent, and severity of coronary atherosclerosis and tend to have an increase in major adverse cardiac events. © 2017 American Heart Association, Inc.

  14. Quantification of normative ranges and baseline predictors of aortoventricular interface dimensions using multi-detector computed tomographic imaging in patients without aortic valve disease

    International Nuclear Information System (INIS)

    Gooley, Robert P.; Cameron, James D.; Soon, Jennifer; Loi, Duncan; Chitale, Gauri; Syeda, Rifath; Meredith, Ian T.

    2015-01-01

    Highlights: • MDCT imaging of the aortoventricular interface is increasingly common. • We present normative ranges for aortoventricular interface dimensions. • Such techniques and ranges should be used to standardise reporting and research. - Abstract: Background: Multidetector computed tomographic (MDCT) assessment of the aortoventricular interface has gained increased importance with the advent of minimally invasive treatment modalities for aortic and mitral valve disease. This has included a standardised technique of identifying a plane through the nadir of each coronary cusp, the basal plane, and taking further measurements in relation to this plane. Despite this there is no published data defining normal ranges for these aortoventricular metrics in a healthy cohort. This study seeks to quantify normative ranges for MDCT derived aortoventricular dimensions and evaluate baseline demographic and anthropomorphic associates of these measurements in a normal cohort. Methods: 250 consecutive patients undergoing MDCT coronary angiography were included. Aortoventricular dimensions at multiple levels of the aortoventricular interface were assessed and normative ranges quantified. Multivariate linear regression was performed to identify baseline predictors of each metric. Results: The mean age was 59 ± 12 years. The basal plane was eccentric (EI = 0.22 ± 0.06) while the left ventricular outflow tract was more eccentric (EI = 0.32 ±0.06), with no correlation to gender, age or hypertension. Male gender, height and body mass index were consistent independent predictors of larger aortoventricular dimensions at all anatomical levels, while age was predictive of supra-annular measurements. Conclusions: Male gender, height and BMI are independent predictors of all aortoventricular dimensions while age predicts only supra-annular dimensions. Use of defined metrics such as the basal plane and formation of normative ranges for these metrics allows reference for clinical

  15. Quantification of normative ranges and baseline predictors of aortoventricular interface dimensions using multi-detector computed tomographic imaging in patients without aortic valve disease

    Energy Technology Data Exchange (ETDEWEB)

    Gooley, Robert P., E-mail: robert.gooley@monashhealth.org [MonashHeart, Monash Health, Melbourne 3168 (Australia); Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia); Cameron, James D., E-mail: james.cameron@monash.edu [MonashHeart, Monash Health, Melbourne 3168 (Australia); Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia); Soon, Jennifer, E-mail: jenn.sa@gmail.com [MonashHeart, Monash Health, Melbourne 3168 (Australia); Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia); Loi, Duncan, E-mail: dloi2@student.monash.edu [Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia); Chitale, Gauri, E-mail: gchi21@student.monash.edu [Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia); Syeda, Rifath, E-mail: rssye1@student.monash.edu [Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia); Meredith, Ian T., E-mail: ian.meredith@myheart.id.au [MonashHeart, Monash Health, Melbourne 3168 (Australia); Monash Cardiovascular Research Centre, Department of Medicine (MMC), Monash University, Melbourne 3168 (Australia)

    2015-09-15

    Highlights: • MDCT imaging of the aortoventricular interface is increasingly common. • We present normative ranges for aortoventricular interface dimensions. • Such techniques and ranges should be used to standardise reporting and research. - Abstract: Background: Multidetector computed tomographic (MDCT) assessment of the aortoventricular interface has gained increased importance with the advent of minimally invasive treatment modalities for aortic and mitral valve disease. This has included a standardised technique of identifying a plane through the nadir of each coronary cusp, the basal plane, and taking further measurements in relation to this plane. Despite this there is no published data defining normal ranges for these aortoventricular metrics in a healthy cohort. This study seeks to quantify normative ranges for MDCT derived aortoventricular dimensions and evaluate baseline demographic and anthropomorphic associates of these measurements in a normal cohort. Methods: 250 consecutive patients undergoing MDCT coronary angiography were included. Aortoventricular dimensions at multiple levels of the aortoventricular interface were assessed and normative ranges quantified. Multivariate linear regression was performed to identify baseline predictors of each metric. Results: The mean age was 59 ± 12 years. The basal plane was eccentric (EI = 0.22 ± 0.06) while the left ventricular outflow tract was more eccentric (EI = 0.32 ±0.06), with no correlation to gender, age or hypertension. Male gender, height and body mass index were consistent independent predictors of larger aortoventricular dimensions at all anatomical levels, while age was predictive of supra-annular measurements. Conclusions: Male gender, height and BMI are independent predictors of all aortoventricular dimensions while age predicts only supra-annular dimensions. Use of defined metrics such as the basal plane and formation of normative ranges for these metrics allows reference for clinical

  16. La trampa del antropomorfismo. Hacia una interfaz (más compleja de lo social The trap of anthropomorphism. Towards a (more complex social interface

    Directory of Open Access Journals (Sweden)

    Iñaki Martínez de Albeniz

    2010-11-01

    Full Text Available La enseñanza de la sociología supone, hoy día, una cura de humildad. Por más que acudamos a sofisticados modelos teóricos (la sociedad líquida, la teoría de sistemas, la fluidez social, la teoría del actor-red, que cuestionan las bases fundacionales de la sociología clásica, la práctica docente evidencia que entre los estudiantes sigue imperando una imagen simple o esquemática de lo social. La sorpresa es mayor si asumimos que se trata de una generación que se ha socializado en el uso de herramientas digitales que facilitan, en principio, la elaboración de mapas más acordes con la complejidad que lo social reviste. El antropomorfismo, la idea de que la sociedad es ante todo un agrupamiento más o menos estable de individuos, es el límite infranqueable que sigue imponiéndose a la hora de entender lo social. Para minar esta visión hegemónica es preciso acudir a disciplinas como el arte (digital, las nuevas tecnología y, en general, las innovaciones estéticas, no tanto para destruir esa representación antropomórfica de lo social sino para desfigurándola prefigurar otras más acordes con una complejidad que ya no sólo intuimos y cuyo aliento sentimos muy cerca. The teaching of sociology is today a humbling experience. Although we use complex theoretical models (the liquid society, system theory, social fluidity or Actor-Network Theory that question the foundational bases of classical sociology, teaching practice shows that a simple or schematic picture of the social continues to prevail among students. The surprise is even greater when we consider that this is a generation that has been socialized in the use of digital tools, a resource that, in principle, should facilitate a mapping of social reality more appropriate to its complexity. Anthropomorphism, the idea that society is primarily a more or less stable grouping of individuals, is the impassable limit that continues to be imposed when it comes to understanding

  17. 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

  18. Clinical significance of computed tomographic arteriography for minute hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, H; Matsui, O; Suzuki, M; Ida, M; Kitagawa, K [Kanazawa Univ. (Japan). School of Medicine

    1982-03-01

    Computed tomographic arteriography (CTA) can clearly demonstrate minute hepatocellular carcinoma (H.C.C.) more than 2 cm in diameter as an enhanced mass lesion. In this case the precise localization of H.C.C. becomes so obvious that CTA plays an important role to evaluate its resectability. However, H.C.C. of the size from 2 cm to 1 cm indiameter, which is visualized with celiac and infusion hepatic angiography, becomes more difficult in detection, and particularly H.C.C. of less than 1 cm in diameter can hardly be recognized, nor be diagnosed as a malignant nodule by CTA, therefore it appears that in these sizes of H.C.C. the detectability of CTA is not superior to the hepatic angiography.

  19. Computer tomographic and angiographic studies of histologically confirmed intrahepatic masses

    International Nuclear Information System (INIS)

    Janson, R.; Lackner, K.; Paquet, K.J.; Thelen, M.; Thurn, P.

    1980-01-01

    The computer tomographic and angiographic findings in 53 patients with intrahepatic masses were compared. The histological findings show that 17 were due to echinococcus, 12 were due to hepatic carcinoma, ten were metastases, five patients had focal nodular hyperplasia, three an alveolar echinococcus and there were three cases with an haemangioma of the liver and a further three liver abscesses. Computer tomography proved superior in peripherally situated lesions, and in those in the left lobe of the liver. Arteriography was better at demonstrating lesions below 2 cm in size, particularly vascular tumours. As a pre-operative measure, angiography is to be preferred since it is able to demonstrate anatomic anomalies and variations in the blood supply, as well as invasion of the portal vein or of the inferior vena cava. (orig.) [de

  20. Computer tomographic and angiographic studies of histologically confirmed intrahepatic masses

    Energy Technology Data Exchange (ETDEWEB)

    Janson, R.; Lackner, K.; Paquet, K.J.; Thelen, M.; Thurn, P.

    1980-06-01

    The computer tomographic and angiographic findings in 53 patients with intrahepatic masses were compared. The histological findings show that 17 were due to echinococcus, 12 were due to hepatic carcinoma, ten were metastases, five patients had focal nodular hyperplasia, three an alveolar echinococcus and there were three cases with an haemangioma of the liver and a further three liver abscesses. Computer tomography proved superior in peripherally situated lesions, and in those in the left lobe of the liver. Arteriography was better at demonstrating lesions below 2 cm in size, particularly vascular tumours. As a pre-operative measure, angiography is to be preferred since it is able to demonstrate anatomic anomalies and variations in the blood supply, as well as invasion of the portal vein or of the inferior vena cava.

  1. Computed tomographic study of hormone-secreting microadenomas

    International Nuclear Information System (INIS)

    Hemminghytt, S.; Kalkhoff, R.K.; Daniels, D.L.; Williams, A.L.; Grogan, J.P.; Haughton, V.M.

    1983-01-01

    A review was made of the computed tomographic (CT) studies of 33 patients with hormone-secreting microadenomas that had been verified by transsphenoidal surgery and endocrinologic evaluation. In previous studies in small series of patients, the CT appearance of pituitary microadenomas has been reported as hypodense, isodense, and hyperdense. In this study, CT showed a region of diminished enhancement and ususally an enlarged pituitary gland in cases of prolactin-secreting adenomas. HGH- or ACTH-secreting adenomas were less consistently hypodense. It is concluded that hypodensity and enlargement in the pituitary gland are the most useful criteria for identification of microadenomas. Some technical factors that may affect the CT appearance of microadenomas and lead to conflicting reports are discussed

  2. Central nervous system leukemia and lymphoma: computed tomographic manifestations

    International Nuclear Information System (INIS)

    Pagani, J.J.; Libshitz, H.I.; Wallace, S.; Hayman, L.A.

    1981-01-01

    Computed tomographic (CT) abnormalities in the brain were identified in 31 of 405 patients with leukemia or lymphoma. Abnormalities included neoplastic masses (15), hemorrhage (nine), abscess (two), other brain tumors (four), and methotrexate leukoencephalopathy (one). CT was normal in 374 patients including 148 with meningeal disease diagnosed by cerebrospinal fluid cytologic examination. Prior to treatment, malignant masses were isodense or of greater density with varying amounts of edema. Increase in size or number of the masses indicated worsening. Response to radiation and chemotherapy was manifested by development of a central low density region with an enhancing rim. CT findings correlated with clinical and cerebrospinal fluid findings. The differential diagnosis of the various abnormalities is considered

  3. 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

  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. 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.

  6. Design of a femtosecond laser assisted tomographic atom probe

    International Nuclear Information System (INIS)

    Gault, B.; Vurpillot, F.; Vella, A.; Gilbert, M.; Menand, A.; Blavette, D.; Deconihout, B.

    2006-01-01

    A tomographic atom probe (TAP) in which the atoms are field evaporated by means of femtosecond laser pulses has been designed. It is shown that the field evaporation is assisted by the laser field enhanced by the subwavelength dimensions of the specimen without any significant heating of the specimen. In addition, as compared with the conventional TAP, due to the very short duration of laser pulses, no spread in the energy of emitted ions is observed, leading to a very high mass resolution in a straight TAP in a wide angle configuration. At last, laser pulses can be used to bring the intense electric field required for the field evaporation on poor conductive materials such as intrinsic Si at low temperature. In this article, the performance of the laser TAP is described and illustrated through the investigation of metals, oxides, and silicon materials

  7. The 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.

    1986-01-01

    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

  8. The accuracy of the ATLAS muon X-ray tomograph

    Science.gov (United States)

    Avramidou, R.; Berbiers, J.; Boudineau, C.; Dechelette, C.; Drakoulakos, D.; Fabjan, C.; Grau, S.; Gschwendtner, E.; Maugain, J.-M.; Rieder, H.; Rangod, S.; Rohrbach, F.; Sbrissa, E.; Sedykh, E.; Sedykh, I.; Smirnov, Y.; Vertogradov, L.; Vichou, I.

    2003-01-01

    A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2 μm systematic and 2 μm statistical uncertainties in the horizontal and vertical directions in the working area 220 cm (horizontal)×60 cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented.

  9. The accuracy of the ATLAS muon X-ray tomograph

    International Nuclear Information System (INIS)

    Avramidou, R.; Berbiers, J.; Boudineau, C.; Dechelette, C.; Drakoulakos, D.; Fabjan, C.; Grau, S.; Gschwendtner, E.; Maugain, J.-M.; Rieder, H.; Rangod, S.; Rohrbach, F.; Sbrissa, E.; Sedykh, E.; Sedykh, I.; Smirnov, Y.; Vertogradov, L.; Vichou, I.

    2003-01-01

    A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2 μm systematic and 2 μm statistical uncertainties in the horizontal and vertical directions in the working area 220 cm (horizontal)x60 cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented

  10. Alveolar echinococcosis of the liver - computed tomographic findings

    International Nuclear Information System (INIS)

    Merkle, E.; Usadel, S.; Vogel, J.; Kern, P.; Friedrich, J.M.; Brambs, H.J.

    1995-01-01

    In order to ascertain the typical computed tomographic findings of hepatic alveolar echinococcosis, 24 computed tomograms of 19 patients were evaluated. The liver was involved in all cases whereas the diaphragma was infiltrated in 32%, and the retroperioteneal area in 42%. The right liver lobe was affected in 65%. Both before and after intravenous bolus contrast medium administration, the lesions were mainly inhomogeneous and of low density; a masking of the lesions due to the contrast medium administration was not observed; the enhancement pattern was irregular. Calcifications were detected in 96% of the cases, cystic structures in 50%, and cholestasis in 54%. On the basis of the crucial finding of calcifications in combination with the other typical observations, CT seems to be very suitable for the evaluation of hepatic alveolar echinococcosis. (orig.) [de

  11. 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).

  12. Computed tomographic findings in children with spastic diplegia

    International Nuclear Information System (INIS)

    Yokochi, Kenji; Horie, Masayo; Inukai, Kazuhisa; Kito, Hideyuki; Shimabukuro, Satoshi; Kodama, Kazuo.

    1989-01-01

    Computed tomographic findings of 46 children with spastic diplegia examined at nine months to three years of age corrected for preterm births were analyzed. Both the size of the lateral ventricles measured by the width of the anterior horns, and the volume of the extracerebral low-density areas were enlarged in some patiens. Both enlargements did not, however, correlate to the severity of the motor abnormality in the patients. The low-density areas of the periventricular white matter, especially adjacent to the trigone, were reduced in many children, probably due to the atrophy of the cerebral white matter having periventricular leukomalacia. The anterior expansion of the white matter reduction from the trigone corresponded to the severer motor abnormality in the children with spastic diplegia. (author)

  13. Tomographic study of temporomandibular joints before orthodontic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ki Jeong [Kyung Hee Univ. College of Dentistry, Seoul (Korea, Republic of)

    2001-12-15

    To determine whether there is a relationship between abnormal temporomandibular joint radiographic findings and age or gender in a sample of preorthodontic patients. Individualized corrected sagittal tomographs of 188 temporomandibular joints in 94 preorthodontic patients, aged 11 to 29 years, were taken and viewed by an observer blinded to clinical records. The study population was divided into 2 aged groups (11-15 years and 16-29 years) for comparative purpose. Temporomandibular joint radiographic findings were classified as normal or abnormal. There was no difference in ratio of abnormal to normal findings between the both aged groups. The frequency of osseous abnormalities was similar with that of abnormalities of condylar position. Abnormalities in CP and JS were most frequent in all aged groups. There is no significant difference between ages or genders for temporomandibular joint radiographic abnormalities.

  14. 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

  15. 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)

  16. 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)

  17. Matching tomographic IMRT fields with static photon fields

    International Nuclear Information System (INIS)

    Sethi, A.; Leybovich, L.; Dogan, N.; Emami, B.

    2001-01-01

    The matching of abutting radiation fields presents a challenging problem in radiation therapy. Due to sharp penumbra of linear accelerator beams, small (1-2 mm) errors in field positioning can lead to large (>30%) hot or cold spots in the abutment region. With head and neck immobilization devices (thermoplastic mask/aquaplast) an average setup error of 3 mm has been reported. Therefore hot or cold spots approaching 50% of the prescription dose may occur along the matchline. Although abutting radiation fields have been investigated for static fields, there is no reported study regarding matching of tomographic IMRT and static fields. Compared to static fields, the matching of tomographic IMRT fields with static fields is more complicated. Since IMRT and static fields are planned on separate treatment planning computers, the dose in the abutment region is not specified. In addition, commonly used techniques for matching fields, such as feathering of junctions, are not practical. We have developed a method that substantially reduces dose inhomogeneity in the abutment region. In this method, a 'buffer zone' around the matchline was created and was included as part of the target for both IMRT and static field plans. In both fields, a small dose gradient (≤3%/mm) in the buffer zone was created. In the IMRT plan, the buffer zone was divided into three sections with dose varying from 83% to 25% of prescription dose. The static field dose profile was modified using either a specially designed physical (hard) or a dynamic (soft) wedge. When these modified fields were matched, the combined dose in the abutment region varied by ≤10% in the presence of setup errors spanning 4 mm (±2 mm) when the hard wedge was used and 10 mm (±5 mm) with the soft wedge

  18. 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

  19. Applicability of a set of tomographic reconstruction algorithms for quantitative SPECT on irradiated nuclear fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsson Svärd, Staffan, E-mail: staffan.jacobsson_svard@physics.uu.se; Holcombe, Scott; Grape, Sophie

    2015-05-21

    A fuel assembly operated in a nuclear power plant typically contains 100–300 fuel rods, depending on fuel type, which become strongly radioactive during irradiation in the reactor core. For operational and security reasons, it is of interest to experimentally deduce rod-wise information from the fuel, preferably by means of non-destructive measurements. The tomographic SPECT technique offers such possibilities through its two-step application; (1) recording the gamma-ray flux distribution around the fuel assembly, and (2) reconstructing the assembly's internal source distribution, based on the recorded radiation field. In this paper, algorithms for performing the latter step and extracting quantitative relative rod-by-rod data are accounted for. As compared to application of SPECT in nuclear medicine, nuclear fuel assemblies present a much more heterogeneous distribution of internal attenuation to gamma radiation than the human body, typically with rods containing pellets of heavy uranium dioxide surrounded by cladding of a zirconium alloy placed in water or air. This inhomogeneity severely complicates the tomographic quantification of the rod-wise relative source content, and the deduction of conclusive data requires detailed modelling of the attenuation to be introduced in the reconstructions. However, as shown in this paper, simplified models may still produce valuable information about the fuel. Here, a set of reconstruction algorithms for SPECT on nuclear fuel assemblies are described and discussed in terms of their quantitative performance for two applications; verification of fuel assemblies' completeness in nuclear safeguards, and rod-wise fuel characterization. It is argued that a request not to base the former assessment on any a priori information brings constraints to which reconstruction methods that may be used in that case, whereas the use of a priori information on geometry and material content enables highly accurate quantitative

  20. 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 accordingl