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Directory of computer users in nuclear medicine

Description: The directory is composed of two major divisions, a Users' section and a Vendors' section. The Users' section consists of detailed installation descriptions and indexes to these descriptions. A typical description contains the name, address, type, and size of the institution as well as names of persons to contact. Following the hardware descriptions are listed the type of studies for which the computers are utilized, including the languages used, the method of output and an estimate of how often the study is performed. The Vendors' section contains short descriptions of current commercially available nuclear medicine systems as supplied by the vendors themselves. In order to reduce the amount of obsolete data and to include new institutions in future updates of the directory, a user questionnaire is included. (HLW)
Date: January 1, 1977
Creator: Henne, R. L.; Erickson, J. J.; McClain, W. J. & Kirch, D. L.
Partner: UNT Libraries Government Documents Department

Sample size for logistic regression with small response probability

Description: The Fisher information matrix for the estimated parameters in a multiple logistic regression can be approximated by the augmented Hessian matrix of the moment generating function for the covariates. The approximation is valid when the probability of response is small. With its use one can obtain a simple closed form estimate of the asymptotic covariance matrix of the maximum likelihood parameter estimates, and thus approximate sample sizes needed to test hypotheses about the parameters. The method is developed for selected distributions of a single covariate, and for a class of exponential-type distributions of several covariates. It is illustrated with an example concerning risk factors for coronary heart disease.
Date: March 1, 1980
Creator: Whittemore, A S
Partner: UNT Libraries Government Documents Department

Center of excellence in laser medicine

Description: Achievements during the first six months of funding to prepare for a Center of Excellence in biomedical laser development include limited specific research projects within the Center's three broad interest areas, and program development to establish the Center and its activities. Progress in the three interest areas -- new medical laser systems development, optical diagnostics, and photosensitization, is reported. Feasibility studies and prototype development were emphasized, to enhance establishing a substantial Center through future support. Specific projects are an optimized laser-catheter system for reversal of vasospasm; optical detection of major skin burn depth and cancers using fluorescent drugs, and photosensitization of vascular tissues. In addition, an interdepartmental Laser Center was established at MGH to enhance collaborations and institutional committment to the Center of Excellence. Competitive postdoctoral research fellowships, with provision for matching funds from other departments, have been announced.
Date: January 1, 1992
Creator: Parrish, J. A.
Partner: UNT Libraries Government Documents Department

Review of information processing in medical imaging. Proceedings of fifth international conference, Nashville, Tennessee, June 27--July 1, 1977

Description: Forty-three papers discuss methods for improvement of the images from radionuclide scans and radiographs for diagnostic purposes. Abstracts of three papers have appeared previously in ERA.
Date: January 1, 1978
Creator: Brill, A.B.; Price, R.R.; McClain, W.J. & Landay, M.W. (comps.)
Partner: UNT Libraries Government Documents Department

Bioethics in America: Who decides

Description: This paper is concerned with the process by which bioethics decisions are made as well as the actual decisions that are reached. The process commonly is one of shared decision-making,'' that is, decisionmaking at several levels, beginning with the government and ending with the individual. After the government has defined a scope of permissible activity, the research or health care institution may further limit what activities are permitted. Finally, the individual patient, or, if the patient is incompetent, the patient's legal representative decides whether or not to participate in the activity. Because bioethics in general, and bioethics related to genetics in particular, evolves through this process of decisionmaking at several levels, this paper briefly traces the process, to see how it works in several areas of bioethics, in order to provide a perspective on the way in which ethical decisions related to genetics are or will be made.
Date: January 1, 1992
Creator: Yesley, M.S.
Partner: UNT Libraries Government Documents Department

Knowledge engineering software: A demonstration of a high end tool

Description: Many investigators wanting to apply knowledge-based systems (KBS) as consultants for cancer diagnosis have turned to tools running on personal computers. While some of these tools serve well for small tasks, they lack the power available with the high end KBS tools such as KEE (Knowledge Engineering Environment) and ART (Automated Reasoning Tool). These tools were originally developed on Lisp machines and have the full functionality of the Lisp language as well as many additional features. They provide a rich and highly productive environment for the software developer. To illustrate the capability of one of these high end tools we have converted a table showing the classification of benign soft tissue tumors into a KEE knowledge base. We have used the tools available in Kee to identify the tumor type for a hypothetical patient. 10 figs.
Date: January 1, 1987
Creator: Salzman, G.C.; Krall, R.B. & Marinuzzi, J.G.
Partner: UNT Libraries Government Documents Department

Monte Carlo analysis of localization errors in magnetoencephalography

Description: In magnetoencephalography (MEG), the magnetic fields created by electrical activity in the brain are measured on the surface of the skull. To determine the location of the activity, the measured field is fit to an assumed source generator model, such as a current dipole, by minimizing chi-square. For current dipoles and other nonlinear source models, the fit is performed by an iterative least squares procedure such as the Levenberg-Marquardt algorithm. Once the fit has been computed, analysis of the resulting value of chi-square can determine whether the assumed source model is adequate to account for the measurements. If the source model is adequate, then the effect of measurement error on the fitted model parameters must be analyzed. Although these kinds of simulation studies can provide a rough idea of the effect that measurement error can be expected to have on source localization, they cannot provide detailed enough information to determine the effects that the errors in a particular measurement situation will produce. In this work, we introduce and describe the use of Monte Carlo-based techniques to analyze model fitting errors for real data. Given the details of the measurement setup and a statistical description of the measurement errors, these techniques determine the effects the errors have on the fitted model parameters. The effects can then be summarized in various ways such as parameter variances/covariances or multidimensional confidence regions. 8 refs., 3 figs.
Date: January 1, 1989
Creator: Medvick, P.A.; Lewis, P.S.; Aine, C. & Flynn, E.R.
Partner: UNT Libraries Government Documents Department

Analysis of the human electroencephalogram with methods from nonlinear dynamics

Description: We apply several different methods from nonlinear dynamical systems to the analysis of the degree of temporal disorder in data from human EEG. Among these are methods of geometrical reconstruction, dimensional complexity, mutual information content, and two different approaches for estimating Lyapunov characteristic exponents. We show how the naive interpretation of numerical results can lead to a considerable underestimation of the dimensional complexity. This is true even when the errors from least squares fits are small. We present more realistic error estimates and show that they seem to contain additional, important information. By applying independent methods of analysis to the same data sets for a given lead, we find that the degree of temporal disorder is minimal in a ''resting awake'' state and increases in sleep as well as in fluroxene induced general anesthesia. At the same time the statistical errors appear to decrease, which can be interpretated as a transition to a more uniform dynamical state. 29 refs., 10 figs.
Date: September 8, 1986
Creator: Mayer-Kress, G. & Holzfuss, J.
Partner: UNT Libraries Government Documents Department

Survey of computer processing of chest radiographs

Description: This paper reviews the work of several investigators who have concerned themselves with various aspects of computer measurement and diagnosis of anatomy present in chest radiography. It is hoped that, at the very least, it will provide a reasonably complete annotated bibliography of this body of research.
Date: January 1, 1977
Creator: Kruger, R. P.
Partner: UNT Libraries Government Documents Department

Flow cytometry: an overview

Description: Flow cytometry has progressed considerably since its inception a decade ago, and major advances not only in measurement techniques, data acquisition, and data analysis but also in areas of biomedical applications appear promising. Flow systems are essentially a marriage between physical techniques and appropriate biological or cytochemical techniques. The dual nature of the method must not be overlooked, particularly by the new user. With the appropriate mating of interests between instrumentation designers (physicists and engineers) and the biomedical users, greater progress can be anticipated in the second decade of this technology. This point is particularly important to consider as more commercial instruments become available to the biomedical community.
Date: January 1, 1978
Creator: Mullaney, P.F. & Jett, J.H.
Partner: UNT Libraries Government Documents Department

(Automation in the clinical laboratory and drug testing programs in the workplace)

Description: The traveler chaired a session on Laboratory Robotics at 4th International Congress on Automation in the Clinical Laboratory. In addition, the traveler chaired a session on Drugs-of-Abuse at 2nd International Congress of Therapeutic Drug Monitoring and Toxicology. In this session, the traveler also presented a paper entitled Development, Implementation and Management of a Drug Testing Program in the Workplace.'' These two Congress were run concurrently in the Congress Center in Barcelona, Spain.
Date: October 17, 1990
Creator: Burtis, Carl
Partner: UNT Libraries Government Documents Department

Pulsatile flow through a tube containing rigid and distensible sections. [Artery prosthetic tubing]

Description: It is common surgical pactice to replace or bypass defective sections of artery with prosthetic tubing that is stiffer than the natural artery. This abrupt variation in elasticity produces distortions of the adjacent flow field that could contribute to the failure of connective sutures or the dislodgement of thrombi, resulting in embolisms downstream. However, by the proper choice of prosthesis diameter one should be able to minimize these adverse effects. A numerical technique has been developed to study the pulsatile flow of blood from a natural artery into a rigid tube of arbitrary diameter. This method is used to investigate the effects of variations in rigid tube diameter on the flow development at the juncture with the distensible artery. The computation procedure is an extension of the arbitrary lagrangian eulerian (ALE) method.
Date: January 1, 1976
Creator: Daly, B. J.
Partner: UNT Libraries Government Documents Department

Diagnostic and therapeutic applications of diode lasers and solid state lasers in medicine

Description: The Texas Medical Center in Houston and the nearby UT Medical Branch at Galveston together constitute a major center of medical research activities. Laser applications in medicine are under development with the engineering assistance of the colloborating engineering centers at Rice University, UT-Austin, and Texas A M Univ. In addition, this collective is collaborating with the Naval Research Laboratory, where new developments in laser design are underway, in order to transfer promising new laser technology rapidly into the medical environment.
Date: May 1, 1992
Creator: Jacques, S.L. (Texas Univ., Houston, TX (United States). Cancer Center); Welch, A.J. (Texas Univ., Austin, TX (United States)); Motamedi, M. (Texas Univ., Galveston, TX (United States). Medical Branch); Rastegar, S. (Texas A and M Univ., College Station, TX (United States)); Tittel, F. (Rice Univ., Houston, TX (United States)) & Esterowitz, L. (Naval Research Lab., Washington, DC (United States))
Partner: UNT Libraries Government Documents Department

The nucleation and growth of calcium oxalate monohydrate on self- assembled monolayers (SAMs)

Description: A physical chemical approach was used to study calcium oxalate monohydrate (COM) nucleation and growth on various organic interfaces. Self-assembling monolayers (SAMs), containing derivatized organic functional groups, were designed to mimic various amino acid residues present in both urine and stone matrix macromolecules. Derivatized surfaces include SAMs with terminal methyl, bromo, imidazole, and thiazolidine-carboxylic acid functional groups. Pronounced differences in COM deposition were observed for the various interfaces with the imidazole and thiazolidine surfaces having the greatest effect and the methyl and bromo groups having little or no nucleating potential.
Date: May 1, 1992
Creator: Campbell, A.A.; Tarasevich, B.J.; Graff, G.L.; Fryxell, G.E. & Rieke, P.C.
Partner: UNT Libraries Government Documents Department

Anatomy studies for an artificial heart. Final summary report

Description: In the interval from February of 1972 through December of 1977, studies were conducted relating to the anatomical feasibility of implanting a total artificial heart system. These studies included both the calf as an experimental animal as well as the ultimate human recipient of the artificial heart system. Studies with the calf included definition of the thoracic anatomy relative to the size, shape, and vascular connections for implanting the blood pump. To test the animal's tolerance to an implanted engine system, mockups of the thermal converter were implanted chronically in various locations within the calf. No problems developed in retroperitoneal or intraperitoneal implants ranging from 8 to 15 months. A study to determine accelerations experienced by an abdominally implanted thermal converter was performed in calves. Under the most severe conditions, accelerations of a maximum of 34 Gs were experienced. The largest effort was devoted to defining the human anatomy relative to implanting an artificial heart in the thorax. From a number of data sources, including cadavers as well as living patients, a quantitative, statistical analysis of the size and shape of the male thorax was obtained. Finally, an in vivo study of a functional intrathoracic compliance bag in a calf demonstrated the feasibility of this method.
Date: December 1, 1977
Creator: Kiraly, R.J. & Nose, Y.
Partner: UNT Libraries Government Documents Department

Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

Description: A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.
Date: January 1, 1993
Creator: Steinkamp, J.A. & Crissman, H.A.
Partner: UNT Libraries Government Documents Department

Flow cytometry for health monitoring in space

Description: Monitoring the health of space station or lunar base residents will be necessary to provide knowledge of the physiological status of astronauts. Flow cytometric techniques are uniquely capable of providing cellular, chromosome, hormone level and enzyme level information. The use of dyes provides the basis for fluorescently labeling specific cellular components. Laser induced fluorescence from stained cells is quantitated in a flow cytometer to measure cellular components such as DNA, RNA and protein. One major application of a flow cytometer will be to perform a complete blood count including hematocrit, hemoglobin content, and numbers of platelets, erythrocytes, granulocytes, lymphocytes and monocytes. A newly developed flow cytometry based fluoroimmunoassay will be able to measure levels of serum enzymes and hormones. It will also be possible to quantitate radiation exposure and some forms of chromosome damage with flow cytometric measurements. With relatively simple modifications to existing technology, it will be possible to construct a flight rated cytometer. 11 references, 6 figures, 2 tables.
Date: January 1, 1984
Creator: Jett, J.H.; Martin, J.C.; Saunders, G.C. & Stewart, C.C.
Partner: UNT Libraries Government Documents Department

Adaptive enhancement of magnetoencephalographic signals via multichannel filtering

Description: A time-varying spatial/temporal filter for enhancing multichannel magnetoencephalographic (MEG) recordings of evoked responses is described. This filter is based in projections derived from a combination of measured data and a priori models of the expected response. It produces estimates of the evoked fields in single trial measurements. These estimates can reduce the need for signal averaging in some situations. The filter uses the a priori model information to enhance responses where they exist, but avoids creating responses that do not exist. Examples are included of the filter's application to both MEG single trial data containing an auditory evoked field and control data with no evoked field. 5 refs., 7 figs.
Date: January 1, 1989
Creator: Lewis, P.S.
Partner: UNT Libraries Government Documents Department

Treatment of bovine cancer-eye (and other animal tumors) with heat

Description: Hyperthermia appears to be an excellent technique for the treatment of a variety of animal tumors. While this report has emphasized the application of hyperthermia to bovine cancer-eye, there cannot be serious doubt about the potential for wider applications of the technique. We have collaborated with the Animal Resource Facility at the University of New Mexico in the successful treatment of a variety of tumors in small animals which would not be a particular interest to stockmen, but the program included the successful treatment of a number of sarcoids in horses. This investigation involving heat effects on sarcoids will continue, but early results appear to be promising. Other veterinarians are using the commercial hyperthermia instruments to treat a variety of small-animal tumors; these practitioners are enthusiastic about the results but no data have been published to date. We have treated an equine lid tumor with good results, and others are pursuing investigations in this area. Use of commercial hyperthermia instruments for treatment of any condition other than bovine cancer-eye or similar small tumors on animals cannot be justified. Like other therapeutic techniques, hyperthermia must be applied to appropriate cases and retreatment will be necessary in some instances. (ERB)
Date: January 1, 1980
Creator: Doss, J.D.
Partner: UNT Libraries Government Documents Department

Digital filtering in a disease detection system

Description: A low-pass, nonrecursive digital filter has been designed to process data in an automated enzyme immunoassay system. The software implemented filter has been installed in the Intel 80/10 system controller. A low-speed sample rate of three samples per second allowed the filter algorithm to be programmed in the high-level FORTRAN language with a resultant execution speed of 0.6 seconds per day array. Fourier techniques are used to derive a zero phase shift filter algorithm from a frequency domain prototype. The resulting alogrithm is modified by a Hamming window to reduce transients and Gibbs phenomenon oscillations. Observations on the effectiveness of the filter under full system operation indicate a 90% data recovery rate.
Date: January 1, 1983
Creator: Brown, R.R.
Partner: UNT Libraries Government Documents Department

Dimensionality of the human electroencephalogram

Description: The goal was to evaluate anesthetic depth in patients by dimensional analysis. Although it was difficult to obtain clean EEG records from the operating room due to noise of electrocautery and movement of the patient's head by operating room personnel. The results are presented on one case of our calculations, followed by a discussion of problems associated with dimensional analysis of the EEG. We consider only two states: aware but quiet, and medium anesthesia. The EEG data we use comes from Hanley and Walts. It was selected because anesthesia was induced by a single agent, and because of its uninterrupted length and lack of artifacts. 26 refs., 27 figs., 1 tab.
Date: January 1, 1986
Creator: Mayer-Kress, G. & Layne, S.P.
Partner: UNT Libraries Government Documents Department

Pilot program to assess proposed basic quality assurance requirements in the medical use of byproduct materials

Description: In January 1990, the Nuclear Regulatory Commission (NRC) proposed amendments to 10 CFR Part 35 that would require medical licensees using byproduct material to establish and implement a basic quality assurance program. A 60-day real-world trial of the proposed rules was initiated to obtain information beyond that generally found through standard public comment procedures. Volunteers from randomly selected institutions had opportunities to review the details of the proposed regulations and to implement these rules on a daily basis during the trial. The participating institutions were then asked to evaluate the proposed regulations based on their personal experiences. The pilot project sought to determine whether medical institutions could develop written quality assurance programs that would meet the eight performance-based objectives of proposed Section 35.35. In addition, the NRC wanted to learn from these volunteers if they had any recommendations on how the rule could be revised to minimized its cost and to clarify its objectives without decreasing its effectiveness. It was found that licensees could develop acceptable QA programs under a performance-based approach, that most licensee programs did meet the proposed objectives, and that most written QA plans would require consultations with NRC or Agreement State personnel before they would fully meet all objectives of proposed Section 35.35. This report describes the overall pilot program. The methodology used to select and assemble the group of participating licensees is presented. The various workshops and evaluation questionnaires are discussed, and detailed findings are presented. 7 refs.
Date: October 1, 1991
Creator: Kaplan, E.; Nelson, K. & Meinhold, C.B. (Brookhaven National Lab., Upton, NY (United States))
Partner: UNT Libraries Government Documents Department

Introduction to veterinary clinical oncology

Description: Veterinary clinical oncology involves a multidisciplinary approach to the recognition and management of spontaneously occurring neoplasms of domestic animals. This requires some knowledge of the causes, incidence, and natural course of malignant disease as it occurs in domestic species. The purpose of this course is to acquaint you with the more common neoplastic problems you will encounter in practice, so that you can offer your clients an informed opinion regarding prognosis and possible therapeutic modalities. A major thrust will be directed toward discussing and encouraging treatment/management of malignant disease. Multimodality therapy will be stressed. 10 refs., 3 tabs.
Date: October 1, 1991
Creator: Weller, R.E.
Partner: UNT Libraries Government Documents Department

Medical applications of synchrotron radiation

Description: Ever since the first diagnostic x-ray was done in the United States on February 3, 1896, the application of ionizing radiation to the field of medicine has become increasingly important. Both in clinical medicine and basic research the use of x-rays for diagnostic imaging and radiotherapy is now widespread. Radiography, angiography, CAT and PETT scanning, mammography, and nuclear medicine are all examples of technologies developed to image the human anatomy. In therapeutic applications, both external and internal sources of radiation are applied to the battle against cancer. The development of dedicated synchrotron radiation sources has allowed exciting advances to take place in many of these applications. The new sources provide tunable, high-intensity monochromatic beams over a wide range of energies which can be tailored to specific programmatic needs. This paper surveys those areas of medical research in which synchrotron radiation facilities are actively involved.
Date: October 1, 1991
Creator: Thomlinson, W.
Partner: UNT Libraries Government Documents Department