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Computed tomography:the details.

Description: Computed Tomography (CT) is a well established technique, particularly in medical imaging, but also applied in Synthetic Aperture Radar (SAR) imaging. Basic CT imaging via back-projection is treated in many texts, but often with insufficient detail to appreciate subtleties such as the role of non-uniform sampling densities. Herein are given some details often neglected in many texts.
Date: July 1, 2007
Creator: Doerry, Armin Walter
Partner: UNT Libraries Government Documents Department
open access

Multi-Modality Phantom Development

Description: Multi-modality imaging has an increasing role in the diagnosis and treatment of a large number of diseases, particularly if both functional and anatomical information are acquired and accurately co-registered. Hence, there is a resulting need for multi modality phantoms in order to validate image co-registration and calibrate the imaging systems. We present our PET-ultrasound phantom development, including PET and ultrasound images of a simple prostate phantom. We use agar and gelatin mixed wit… more
Date: March 20, 2009
Creator: Huber, Jennifer S.; Peng, Qiyu & Moses, William W.
Partner: UNT Libraries Government Documents Department
open access

Software Programmable Multi-Mode Interface for Nuclear-Medical Imaging

Description: An innovative multi-port interface allows gamma camera events (spatial coordinates and energy) to be acquired concurrently with a sampling of physiological patient data. The versatility of the interface permits all conventional static, dynamic, and tomographic imaging modes, in addition to multi-hole coded aperture acquisition. The acquired list mode data may be analyzed or gated on the basis of various camera, isotopic, or physiological parameters.
Date: January 1, 1982
Creator: Zubal, I. G.; Rowe, R. W.; Bizais, Y. J. C.; Bennett, G. W. & Brill, A. B.
Partner: UNT Libraries Government Documents Department
open access

Clamshell tomograph

Description: 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… more
Date: January 29, 1982
Creator: Derenzo, S.E. & Budinger, T.F.
Partner: UNT Libraries Government Documents Department
open access

The high sensitivity of the maximum likelihood estimator method of tomographic image reconstruction

Description: Positron Emission Tomography (PET) images obtained by the MLE iterative method of image reconstruction converge towards strongly deteriorated versions of the original source image. The image deterioration is caused by an excessive attempt by the algorithm to match the projection data with high counts. We can modulate this effect. We compared a source image with reconstructions by filtered backprojection to the MLE algorithm to show that the MLE images can have similar noise to the filtered back… more
Date: January 1, 1987
Creator: Llacer, J. & Veklerov, E.
Partner: UNT Libraries Government Documents Department
open access

Matrix-based image reconstruction methods for tomography

Description: Matrix methods of image reconstruction have not been used, in general, because of the large size of practical matrices, ill condition upon inversion and the success of Fourier-based techniques. An exception is the work that has been done at the Lawrence Berkeley Laboratory for imaging with accelerated radioactive ions. An extension of that work into more general imaging problems shows that, with a correct formulation of the problem, positron tomography with ring geometries results in well behav… more
Date: October 1, 1984
Creator: Llacer, J. & Meng, J.D.
Partner: UNT Libraries Government Documents Department
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Three-Phase Material Distribution Measurements in a Vertical Flow Using Gamma-Densitometry Tomography and Electrical-Impedance Tomography

Description: Experiments are presented in which electrical-impedance tomography (EIT) and gamma-densitometry tomography (GDT) measurements were combined to simultaneously measure the solid, liquid, and gas radial distributions in a vertical three-phase flow. The experimental testbed was a 19.05-cm diameter bubble column in which gas is injected at the bottom and exits out the top while the liquid and solid phases recirculate. The gas phase was air and the liquid phase was deionized water with added electrol… more
Date: March 28, 2000
Creator: George, Darin L.; Shollenberger, Kim Ann; Torczynski, John R.; O'Hern, Timothy J. & Ceccio, S. L.
Partner: UNT Libraries Government Documents Department
open access

Interface Requirements in Nuclear Medicine Devices and Systems

Description: Interface designs for three nuclear medicine imaging systems, and computer networking strategies proposed for medical imaging departments are presented. Configurations for two positron-emission-tomography devices (PET III and ECAT) and a general-purpose tomography instrument (the UNICON) are analyzed in terms of specific performance parameters. Interface designs for these machines are contrasted in terms of utilization of standard versus custom modules, cost, and ease of modification, upgrade, … more
Date: January 1, 1982
Creator: Maguire, G. Q., Jr.; Brill, A. B. & Noz, M. E.
Partner: UNT Libraries Government Documents Department
open access

Algorithm for Rapid Tomography of Gas Concentrations

Description: We present a new computed tomography method, the low third derivative (LTD) method, that is particularly suited for reconstructing the spatial distribution of gas concentrations from path-integral data for a small number of optical paths. The method finds a spatial distribution of gas concentrations that (1) has path integrals that agree with measured path integrals, and (2) has a low third spatial derivative in each direction, at every point. The trade-off between (1) and (2) is controlled by … more
Date: June 27, 2000
Creator: Price, P. N.; Fischer, M. L.; Gadgil, A. J. & Sextro, R. G.
Partner: UNT Libraries Government Documents Department
open access

Quantitative Clinical Evaluation of a Simultaneous PETI MRI Breast Imaging System

Description: A prototype simultaneous PET-MRI breast scanner has been developed for conducting clinical studies with the goal of obtaining high resolution anatomical and functional information in the same scan which can lead to faster and better diagnosis, reduction of unwanted biopsies, and better patient care.
Date: April 3, 2013
Creator: Schlyer D. J. & Schlyer, D. J.
Partner: UNT Libraries Government Documents Department
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Kinetic analysis of dynamic PET data

Description: Our goal is to quantify regional physiological processes such as blood flow and metabolism by means of tracer kinetic modeling and positron emission tomography (PET). Compartmental models are one way of characterizing the behavior of tracers in physiological systems. This paper describes a general method of estimating compartmental model rate constants from measurements of the concentration of tracers in blood and tissue, taken at multiple time intervals. A computer program which applies the me… more
Date: December 1, 1983
Creator: Knittel, B.
Partner: UNT Libraries Government Documents Department
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The parallel implementation of a backpropagation neural network and its applicability to SPECT image reconstruction

Description: The objective of this study was to determine the feasibility of using an Artificial Neural Network (ANN), in particular a backpropagation ANN, to improve the speed and quality of the reconstruction of three-dimensional SPECT (single photon emission computed tomography) images. In addition, since the processing elements (PE)s in each layer of an ANN are independent of each other, the speed and efficiency of the neural network architecture could be better optimized by implementing the ANN on a ma… more
Date: January 1, 1992
Creator: Kerr, J.P.
Partner: UNT Libraries Government Documents Department
open access

3d Image Reconstruction for PET by Multi-Slice Rebinning and Axial Filtering. [Positron Emission Tomography (Pet)]

Description: Two different approaches are used at present to reconstruct from 3D coincidence data in PET. We refer to these approaches as the single-slice rebinning approach and the fully-3D approach. The single-slice rebinning approach involves geometrical approximations, but it requires the least possible amount of computation. Fully-3D reconstruction algorithms, both iterative and non-iterative, do not make such approximations, but require much more computation. Multi-slice rebinning with axial filtering… more
Date: January 1, 1991
Creator: Lewitt, R. M.; Muehllehner, G. & Karp, J. S.
Partner: UNT Libraries Government Documents Department
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High Resolution Tomographic Instrument Development

Description: 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 tomo… more
Date: January 1, 1992
Partner: UNT Libraries Government Documents Department
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Image reconstruction for a Positron Emission Tomograph optimized for breast cancer imaging

Description: The author performs image reconstruction for a novel Positron Emission Tomography camera that is optimized for breast cancer imaging. This work addresses for the first time, the problem of fully-3D, tomographic reconstruction using a septa-less, stationary, (i.e. no rotation or linear motion), and rectangular camera whose Field of View (FOV) encompasses the entire volume enclosed by detector modules capable of measuring Depth of Interaction (DOI) information. The camera is rectangular in shape … more
Date: April 1, 2000
Creator: Virador, Patrick R.G.
Partner: UNT Libraries Government Documents Department
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Cyclotrons for clinical and biomedical research with PET

Description: The purpose of this commentary is to present some background material on cyclotrons and other particle accelerators particularly with a view toward the considerations behind acquiring and installing such a machine for purely clinical and/or biomedical research use.
Date: January 1, 1987
Creator: Wolf, A.P.
Partner: UNT Libraries Government Documents Department
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Microaspiration for high-pressure freezing: a new method for ultrastructural preservation of fragile and sparse tissues for TEM and electron tomography

Description: High-pressure freezing is the preferred method to prepare thick biological specimens for ultrastructural studies. However, the advantages obtained by this method often prove unattainable for samples that are difficult to handle during the freezing and substitution protocols. Delicate and sparse samples are difficult to manipulate and maintain intact throughout the sequence of freezing, infiltration, embedding, and final orientation for sectioning and subsequent TEM imaging. An established appro… more
Date: February 13, 2008
Creator: Auer, Manfred; Triffo, W. J.; Palsdottir, H.; McDonald, K. L.; Inman, J. L.; Bissell, M. J. et al.
Partner: UNT Libraries Government Documents Department
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Detectors, sampling, shielding, and electronics for positron emission tomography

Description: A brief discussion of the important design elements for positron emission tomographs is presented. The conclusions are that the instrumentation can be improved by the use of larger numbers of small, efficient detectors closely packed in many rings, the development of new detector materials, and novel electronic designs to reduce the deadtime and increase maximum event rates. (ACR)
Date: August 1, 1981
Creator: Derenzo, S.E.
Partner: UNT Libraries Government Documents Department
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Grain boundary characterization in an X750 alloy

Description: Grain boundary chemistry in an X750 Ni alloy was analyzed by atom probe tomography in an effort to clarify the possible roles of elemental segregation and carbide presence on the stress corrosion cracking behavior of Ni alloys. Two types of cracks are observed: straight cracks along twin boundaries and wavy cracks at general boundaries. It was found that carbides (M23C6 and TiC) are present at both twin and general boundaries, with comparable B and P segregation for all types of grain boundarie… more
Date: November 1, 2012
Creator: Fisher, Kevin; Teysseyre, Sebastien & Marquis, Emmanuelle
Partner: UNT Libraries Government Documents Department
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Policy Implications of the Computed Tomography (CT) Scanner

Description: A report by the Office of Technology Assessment (OTA) that looks specifically at the Computed Tomography (CT) scanner and examines "current Federal policies and current medical practices to determine whether a reasonable amount of justification should be provided before costly new medical technologies and procedures are put into general use," (quoted from p. iii).
Date: November 1978
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department
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Digital Radiography and Computed Tomography (DRCT) Product Improvement Plan (PIP)

Description: The Idaho National Laboratory (INL) has been developing and deploying x-ray inspection systems for chemical weapons containers for the past 12 years under the direction of the Project Manager for Non-Stockpile Chemical Materiel (PMNSCM). In FY-10 funding was provided to advance the capabilities of these systems through the DRCT (Digital Radiography and Computed Tomography) Product Improvement Plan (PIP), funded by the PMNSCM. The DRCT PIP identified three research tasks; end user study, detecto… more
Date: December 1, 2010
Creator: Roney, Tim; Pink, Bob; Wendt, Karen; Seifert, Robert & Smith, Mike
Partner: UNT Libraries Government Documents Department
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