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in subjects: "Diagnostic Techniques"

open access

Applications of mesoscopic physics

This report discusses the following topics: Acoustical nondestructive evaluation of heterogeneous materials in the multiple scattering regime. Classical and quantum superdiffusion in a time-dependent random potential. Negative Magnetoresistance in Variable Range Hopping Conduction. Reproducible Conductance Fluctuations in Macroscopic Anderson Insulators. Feasibility of far-infared lasers using multiple semiconductor quantum wells.

Date: January 1, 1992

Creator: Feng, Shechao.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Performance of a coincidence based blood activity monitor

A new device has been constructed that measures the positron emitting radio-tracer concentration in arterial blood by extracting blood with a peristaltic pump, then measuring the activity concentration by detecting coincident pairs of 511 keV photons with a pair of heavy inorganic scintillators attached to photomultiplier tubes. The sensitivity of this device is experimentally determined to be 610 counts/second per {mu}Ci/ml, and has a paralyzing dead time of 1.2 {mu}s, so is capable of measuri… more

Date: December 1, 1989

Creator: Moses, W. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Stochastic modelling of physiologic processes with radiotracers and positron emission tomography

The compartment model, so often used in nuclear medicine and in pharmacokinetics, is formed by a set of linear differential equations of order one with constant coefficients; its validity depends upon the hypothesis that the system described contains a finite number of components, and that each component is homogeneous. These hypotheses exclude the presence of diffusion and of age-dependent processes, or in general of transport of a non-Markovian nature. The fact that frequently the experimenta… more

Date: January 1, 1982

Creator: Rescigno, A.; Lambrecht, R. M. & Duncan, C. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ORIS: the Oak Ridge Imaging System program listings. [Nuclear medicine imaging with rectilinear scanner and gamma camera]

The Oak Ridge Imaging System (ORIS) is a general purpose access, storage, processing and display system for nuclear medicine imaging with rectilinear scanner and gamma camera. This volume contains listings of the PDP-8/E version of ORIS Version 2. The system is designed to run under the Digital Equipment Corporation's OS/8 monitor in 16K or more words of core. System and image file mass storage is on RK8E disk; longer-time image file storage is provided on DECtape. Another version of this … more

Date: April 1, 1978

Creator: Bell, P. R. & Dougherty, J. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Emission computed tomography of /sup 18/F-fluorodeoxyglucose and /sup 13/N-ammonia in stroke and epilepsy

The ECAT Positron Tomograph was used to scan normal control subjects, stroke patients at various times during recovery, and patients with partial epilepsy during EEG monitoring. /sup 18/F-fluorodeoxyglucose (/sup 18/FDG) and /sup 13/N-Ammonia (/sup 13/NH/sub 3/) were used as indicators of abnormalities in local cerebral glucose utilization (LCMR/sub glc/) and relative perfusion, respectively. Hypometabolism, due to deactivation or minimal damage, was demonstrated with the /sup 18/FDG scan in de… more

Date: January 1, 1980

Creator: Kuhl, D. E.; Phelps, M. E. & Engel Jr., J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

VUV (vacuum ultraviolet) laser diagnostics of H sup - ion sources

Vacuum ultraviolet laser absorption spectroscopy has been employed to measure the populations and temperatures of ground electronic state H-atoms and vibrationally-excited H{sub 2} molecules in a volume H{sup -} ion source. Measurements of both species have been made under a variety of discharge conditions. Vibrational levels to v{double prime}=8 have been measured, with the vibrational population distribution well described by a temperature of 4150K. 10 refs., 9 figs.

Date: November 1, 1989

Creator: Young, A. T.; Stutzin, G. C.; Leung, K. N. & Kunkel, W. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Short-lived positron emitter labeled radiotracers - present status

The preparation of labelled compounds is important for the application of positron emission transaxial tomography (PETT) in biomedical sciences. This paper describes problems and progress in the synthesis of short-lived positron emitter (/sup 11/C, /sup 18/F, /sup 13/N) labelled tracers for PETT. Synthesis of labelled sugars, amino acids, and neurotransmitter receptors (pimozide and spiroperidol tagged with /sup 11/C) is discussed in particular. (DLC)

Date: January 1, 1982

Creator: Fowler, J. S. & Wolf, A. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dedicated medical ion accelerator design study. Final report

Results and conclusions are reported from a design study for a dedicated medical accelerator. Basing efforts on the current consensus regarding medical requirements, the resulting demands on accelerator and beam delivery systems were analyzed, and existing accelerator technology was reviewed to evaluate the feasibility of meeting these demands. This general analysis was augmented and verified by preparing detailed preliminary designs for sources of therapeutic beams of neutrons, protons and hea… more

Date: December 1, 1977

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Acceleration of electrons using an inverse free electron laser auto- accelerator

We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at {approximately}1.65 mm is developed along the first section of an undulator inside a quasi-o… more

Date: July 1, 1992

Creator: Wernick, I.K. & Marshall, T.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Geothermal Injection Monitoring Project. Phase I status report, April 1981-April 1982

The feasibility of using remote geophysical techniques to monitor the movement of injected brine has been evaluated. It was established that no single approach is likely to be identified that can be used to accurately monitor the precise location of the injected fluid. Several approaches have been considered in parallel because they add new dimensions to the existing monitoring capabilities, and are likely to cover a range of applications at a variety of geothermal sites. These include: microse… more

Date: August 13, 1982

Creator: Younker, L.; Hanson, J.; Didwall, E.; Kasameyer, P.; Smith, A.; Hearst, J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Detection sensitivity of x-ray CT imaging for NDE of green-state ceramics

Improved ceramic-processing methods that use pressure slip-casting and injection molding are being developed at Norton Advanced Ceramics, with a goal of producing reliable structural ceramics for advanced heat engines. Nondestructive evaluation (NDE) of ceramic parts at different stages of processing can provide useful diagnostic information to help improve processing techniques. For example, an evaluation of density gradients in as-cast green-body samples can be used to judge mold performance … more

Date: 1991~

Creator: Gopalsami, N.; Rizo, P.; Ellingson, W. A. & Tracey, D. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Kinetic analysis of dynamic PET data

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.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Detection and diagnosis of abnormal transients in nuclear power plants

This document describes a simulation-based algorithm that combines fuzzy logic with macroscopic conservation equations to diagnose multiple-failure events subject to uncertainties in transient data. Clusters of single-failure data points of similar characteristics are obtained through a pattern recognition algorithm and the cluster centers are combined in the space of macroscopic inventory derivatives to generate multiple-failure cluster centers. A fuzzy membership function is used to represent… more

Date: January 1, 1991

Creator: Lee, J. C.; Rank, P. J.; Hawkes, E.; Wehe, D. K. (Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering) & Reifman, J. (Argonne National Lab., IL (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Advances in Diagnostic Instrumentation

Developments in medical imaging in the last ten years are described. Techniques include fine focus x-ray tubes, computerized tomography, emission tomography, and ultrasonography. (ACR)

Date: January 1, 1980

Creator: Perez-Mendez, V.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Quantitative nondestructive density determinations of very low-density carbon foams

The carbon density and the carbon distribution in low-density foams that were manufactured by a modified salt-replica process were determined by bulk measurements of weight and volume and by x-ray computed tomography (CT). When determining the carbon density, both methods yielded similar results, however, the high spatial resolution of CT was found to yield nondestructive quantitative information on the carbon distribution that was not available from bulk measurements. The highest and lowest fo… more

Date: January 1, 1991

Creator: Moddeman, W. E.; Kramer, D. P.; Firsich, D. W.; Trainer, P. D.; Back, P. S.; Smith, S. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Genes and gene expression: Localization, damage and control -- A multilevel and inter-disciplinary study

All projects are working toward a goal for describing the three dimensional nuclear topography in terms of relative spatial relationships among genes (specific DNA sequence). Methods are now being perfected to detect these genes, quantitatively and spatially, to perturb these genes specifically, and to measure the perturbation in order to assure specificity. We are developing methods to assay, after perturbation of the target DNA within living cells, whether or not only the target sequence are … more

Date: September 1, 1990

Creator: Ts'o, P.O.P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Cyclotrons for clinical and biomedical research with PET

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Application of artificial intelligence to melter control: Realtime process advisor for the scale melter facility

The Defense Waste Processing Facility (DWPF) at the Savannah River Plant (SRP) is currently under construction and when completed will process high-level radioactive waste into a borosilicate glass wasteform. This facility will consist of numerous batch chemical processing steps as well as the continuous operation of a joule-heated melter and its off-gas treatment system. A realtime process advisor system based on Artificial Intelligence (AI) techniques has been developed and is currently in us… more

Date: January 1, 1988

Creator: Edwards, Jr, R E

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent developments in positron emission tomography (PET) instrumentation

This paper presents recent detector developments and perspectives for positron emission tomography (PET) instrumentation used for medical research, as well as the physical processes in positron annihilation, photon scattering and detection, tomograph design considerations, and the potentials for new advances in detectors. 117 refs., 4 figs., 4 tabs.

Date: April 1, 1986

Creator: Derenzo, S.E. & Budinger, T.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

MLE (Maximum Likelihood Estimator) reconstruction of a brain phantom using a Monte Carlo transition matrix and a statistical stopping rule

In order to study properties of the Maximum Likelihood Estimator (MLE) algorithm for image reconstruction in Positron Emission Tomographyy (PET), the algorithm is applied to data obtained by the ECAT-III tomograph from a brain phantom. The procedure for subtracting accidental coincidences from the data stream generated by this physical phantom is such that he resultant data are not Poisson distributed. This makes the present investigation different from other investigations based on computer-si… more

Date: October 1, 1987

Creator: Veklerov, E.; Llacer, J. & Hoffman, E.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Microscopy and Elemental Analysis in Tissue Samples Using Computed Microtomography With Synchrotron X-Rays

The initial development shows that CMT using synchrotron x-rays can be developed to ..mu..m spatial resolution and perhaps even better. This creates a new microscopy technique which is of special interest in morphological studies of tissues, since no chemical preparation or slicing of the sample is necessary. The combination of CMT with spatial resolution in the ..mu..m range and elemental mapping with sensitivity in the ppM range results in a new tool for elemental mapping at the cellular leve… more

Date: January 1, 1988

Creator: Spanne, P. & Rivers, M. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Geotomography applied at the Stripa Mine in Sweden

LLNL made ultrahigh-frequency (450-MHz) electromagnetic borehole-to-borehole transmissions in the Stripa Mine near Guldsmedshyttan, Sweden, in April 1979. Transmission loss measurements were made between four sets of 76-mm boreholes 30 m long, located at the end of a drift. Distances between the boreholes varied from 2 to 22 m. More than 25,000 data points were taken. A geotomograph was constructed to show the variation of attenuation between boreholes. The observed spatial variation of electro… more

Date: April 7, 1980

Creator: Okada, J.T.; Laine, E.F.; Lytle, R.J. & Daily,W.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Comparison of x-ray computed tomography, through-transmission ultrasound, and low-kV x-ray imaging for characterizing green-state ceramics

Green-state MgAl/sub 2/O/sub 4/ compact disk specimens have been studied by x-ray computed tomography (CT), through-transmission pulsed ultrasound, and low-kV x-ray imaging to compare the abilities of these nondestructive evaluation (NDE) methods to detect flaws and density variations. X-ray computed tomographic images were obtained from a 125-kV (peak) imaging system with a 512 x 512 matrix and a pixel size of 100 ..mu..m. A 3- to 10- MHz focused-beam ultrasonic transducer was used, together w… more

Date: June 1, 1985

Creator: Roberts, R. A.; Ellingson, W. A. & Vannier, M. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Positron computed tomography: current state, clinical results and future trends

An overview is presented of positron computed tomography: its advantages over single photon emission tomography, its use in metabolic studies of the heart and chemical investigation of the brain, and future trends. (ACR)

Date: September 1, 1980

Creator: Schelbert, H. R.; Phelps, M. E. & Kuhl, D. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department