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Development and use of a fifteen year-old equivalent mathematical phantom for internal dose calculations. [Radiation dose distributions from /sup 99m/Tc-labeled compounds]

Description: The existence of a phantom based on anatomical data for the average fifteen-year-old provides for a proficient means of obtaining estimates of absorbed dose for children of that age. Dimensions representative of an average fifteen-year-old human, obtained from various biological and medical research, were transformed into a mathematical construct of idealized shapes of the exterior, skeletal system, and internal organs of a human. The idealization for an average adult presently in use by the International Commission on Radiological Protection was used as a basis for design. The mathematical equations describing the phantom were developed to be readily adaptable to present-day methods of dose estimation. Typical exposure situations in nuclear medicine have previously been modeled for existing phantoms. With no further development of the exposure model necessary, adaptation to the fifteen-year-old phantom demonstrated the utility of the design. Estimates of absorbed dose were obtained for the administration of two radiopharmaceuticals, /sup 99m/Tc-sulfur colloid and /sup 99m/Tc-DMSA. (auth)
Date: June 1, 1976
Creator: Jones, R. M.; Poston, J. W.; Hwang, J. L.; Jones, T. D. & Warner, G. G.
Partner: UNT Libraries Government Documents Department

Positron imaging with multiwire proportional chamber-gamma converter hybrid detectors

Description: A large area positron camera was developed using multiwire proportional chambers as detectors and electromagnetic delay lines for coordinate readout. Honeycomb structured gamma converters made of lead are coupled to the chambers for efficient gamma detection and good spatial resolution. Two opposing detectors, each having a sensitive area of 48 cm x 48 cm, are operated in coincidence for the detection of annihilation gammas (511 keV) from positron emitters. Detection efficiency of 4.2 percent per detector and spatial resolution of 6 to 7 mm FWHM at the mid-plane were achieved. The present camera operates at a maximum count rate of 24 K counts/min, limited by accidental coincidence. The theory for the gamma converter is presented along with a review of the operation of the multiwire proportional chamber and delay line readout. Calculated gamma converter efficiencies are compared with the measured results using a prototype test chamber. The characteristics of the positron camera system is evaluated, and the performance is shown to be consistent with calculation.
Date: September 1, 1976
Creator: Chu, D. Y. H.
Partner: UNT Libraries Government Documents Department

Development of a mathematical phantom representing a 10-year-old child for use in internal dosimetry calculations. [Radiation dose calculations]

Description: With the increased growth of nuclear energy generating facilities, estimates of absorbed radiation dose to human population groups (e.g., children) are required. In addition, children are being exposed to many nuclear medicine procedures and accurate dose estimates are needed. The main purpose of this research is to design a mathematical phantom representing as closely as possible a 10-year old child. (auth)
Date: January 1, 1976
Creator: Deus, S. F. & Poston, J. W.
Partner: UNT Libraries Government Documents Department

In vivo metabolism of I-123 labeled semisynthetic low density lipoproteins

Description: We previously observed that small model beta-strand peptides (MBPs) selectively bind to human low density lipoprotein (hLDL) in vitro, and that some MBPs can be labeled with I-123-tyramine cellobiose (I-123-TyC). We hypothesized that metabolism of semisynthetic hLDL should mimic that of covalently labeled native hLDL, and planned to evaluate the biodistribution in rabbits of semisynthetic hLDL; to determine effects of prior oxidation and acetylation of the adsorbing hLDL on binding of MBPs and upon biodistribution of semisynthetic particles; and to begin biodistribution studies with semisynthetic hLDL in human subjects, with the eventual goal of application to experimental and clinical nuclear imaging studies. We have synthesized a radioiodotyrosine-containing MBP, designated betay, as a more suitable adsorbant to hLDL thanradioiodine-TyC-MBP, and optimized conditions for preparing radioiodine-betaY:hLDL. In rabbits both betaY and betaY:hLDL complexes were cleared from the bloodstream much more rapidly than radioiodine-TyC-hLDL or In-111-hLDL, and betaY in either form showed a biodistribution pattern different from that of directly radiolabeled hLDL. Even though radioiodine-betaY can be quickly and easily produced, we conclude that neither betaY alone nor semisynthetic betaY:hLDL particles are likely to prove useful as tracers of hLDL metabolism in vivo.
Date: December 1, 1990
Creator: Harper, P. V.
Partner: UNT Libraries Government Documents Department

New imaging systems in nuclear medicine. Technical progress report, July 1, 1975--March 15, 1976. [Positron imaging systems]

Description: This progress report covers four areas: development of positron instrumentation, development of NUMEDICS computer system and software, application of cyclotron-produced isotopes (/sup 11/C, /sup 68/Ga, /sup 13/N, /sup 15/O, and /sup 82/Rb), and application of the NUMEDICS computer system in nuclear medicine. The development of transverse section positron imaging has had a significant impact and a positron camera was designed specifically for transverse section imaging of heart and lungs. The computer net (NUMEDICS II) is progressing rapidly in design and software development. Clinical studies have demonstrated the feasibility of measuring cerebral blood flow using a variety of positron emitting radiopharmaceuticals and oxygen utilization using /sup 15/O/sub 2/. Rubidium-82 also appears to be a promising agent for measurement of cerebral blood flow.
Date: January 1, 1976
Creator: Brownell, G. L.
Partner: UNT Libraries Government Documents Department

In vivo mutagenicity and clastogenicity of ionizing radiation in nuclear medicine

Description: The overall goal of our research remains to investigate the mutagenic and clastogenic effects of exposure to low levels of ionizing radiation to human lymphocytes. Principally, we are studying hospital patients referred to a nuclear medicine department for diagnostic cardiac imaging and nuclear medicine technologies who administer radionuclides. Emphasis in the first year, as described in the first progress report, was on optimization of the hprt mutation assay, measurement of mutant frequencies in patients imaged with thallium-201, and measurement of mutant frequencies in controls. Emphasis in the second year has been on measurements of (1) chromosome aberrations in patients imaged with thallium-201, (2) mutant frequencies in patients imaged with technetium-99, (3) mutant frequencies in nuclear medicine technicians and physical therapists, (4) mutant frequencies in patients treated for Hodgkins disease with radiotherapy. The progress in these areas is described.
Date: January 1, 1991
Creator: Kelsey, K. T.
Partner: UNT Libraries Government Documents Department

Method for recycling radioactive noble gases for functional pulmonary imaging

Description: A theoretical treatment of the dynamic adsorption and desorption processes in the adsorption column is developed. The results of this analysis are compared with the space-time measurements of /sup 133/Xe activity distribution in a charcoal column, when trace amounts of this gas in exponentially decreasing concentrations are fed into the column. Based on these investigations, a recycling apparatus is designed for use with xenon isotopes, especially /sup 127/Xe, in studies of pulmonary function. The apparatus takes advantage of the high adsorbability of activated coconut charcoal for xenon a low temperature (-78/sup 0/C) in order to trap the radioactive xenon gas that is exhaled during each ventilation-perfusion study. The trapped xenon is then recovered by passing low-pressure steam through the charcoal column. It is found that steam removes xenon from the surface of the charcoal more effectively than does heating and evacuation of the charcoal bed. As a result, an average xenon recovery of 96 percent has been achieved. Improved design parameters are discussed. (auth)
Date: May 1, 1976
Creator: Forouzan-Rad, M.
Partner: UNT Libraries Government Documents Department

Applications of isotopes. [Need and cost of stable iotopes for use as tracers in biomedical and environmental studies]

Description: Current and potential applications of stable isotopes as tracers in a number of biomedical and environmental areas are discussed. It is pointed out that a wide variety of problems exist in these fields whose solutions in principle are amenable to the isotopic approach. The number and diversity of these problems as well as the unique role stable isotopes can play in their solution illustrate the importance of achieving and maintaining a broad inventory of isotopic species. Experience has demonstrated unequivocally an additional overriding requirement for widespread exploration of stable isotopes by the scientific and technical community, i.e., the need for low cost availability of the materials in quantity. Some representative applications of /sup 12/C, /sup 13/C, /sup 14/N, /sup 15/N, /sup 16/O, /sup 17/O, and /sup 18/O are discussed.
Date: January 1, 1976
Creator: Kirby-Smith, J. S.
Partner: UNT Libraries Government Documents Department

High efficiency gamma converters and their application in a MWPC positron camera

Description: Honeycomb structured lead ..gamma..-ray converters have been developed and coupled with Multiwire Proportional Chambers to produce a position-sensitive hybrid detector for spatial localization of MeV range ..gamma.. rays. Two such detectors operated in time coincidence mode function as a large-area large-solid-angle positron camera. The sensitivity of the camera system is measured to be 1600 counts/min-..mu..Ci, corresponding to a detection efficiency of 5.5 percent per detector. Images of phantoms and clinical objects are obtained by using the back-projection reconstruction method, and the results demonstrate the tomographic capability of such a positron camera system. A design analysis of the ..gamma.. converter is presented, the detection efficiencies of converters of various dimensions are measured, and the results agree quite well with calculation. Further improvements in converter efficiency can be expected with modifications in the converter designs based on the concepts of enhanced surface area and uniformity of electron extraction field. The new converters under consideration are made of small-diameter high-lead-content lead glass tubing made conductive by hydrogen reduction treatment.
Date: October 1, 1976
Creator: Chu, D.; Tam, K. C.; Perez-Mendez, V.; Kaplan, S. N. Lim, C. B.; Hattner, R.; Kaufman, L. et al.
Partner: UNT Libraries Government Documents Department

Evaluative studies in nuclear medicine research. Interim progress report, July 1, 1975--June 30, 1976. [Diagnostic value of brain scans]

Description: Data relating to the determination of the efficacy of radionuclide brain scanning have been analyzed. The data were gathered at a teaching hospital by use of a prospective questionnaire followed by a retrospective study of the result of the brain scan examination. Data analysis was accomplished using a method of pattern discovery which relates selected outcomes such as normal and abnormal brain scans to patient attributes (signs, symptoms, history, and previous test results). The objective of the analysis was the identification of patterns or clusters of patient attributes which have a high probability of acting as predictors of the outcome of the brain scan.
Date: January 1, 1976
Creator: Potchen, E. J.
Partner: UNT Libraries Government Documents Department

Three-dimensional imaging with large-area positron cameras

Description: Cameras for nuclear medicine imaging which use the two back-to-back gamma rays from a positron annihilation have the unique property of being able to give images of positron-emitting radionuclide distributions without the use of collimators and the associated large loss of intensity. Cameras with two parallel opposing planar gamma-ray detectors are now commonly used without camera movement to give tomographic images of a number of transverse planes through the positron emitting object. Each of these tomographic images, the set of intersections of the decay-gamma event lines with that plane, has source points in that plane in focus but superimposed on a large background from the blurred-out images from the other planes. We present here a method of three dimensional image reconstruction of these positron images which uses a single exposure to remove the blurred off-plane activity from all tomographic planes simultaneously. The tomographic image on a plane is the sum of contributions from all source planes, each contribution being the convolution of the source distribution on a plane with the camera system point response function for that plane. Fourier transformation of the set of tomographic image equations gives a set of linear equations whose solution, after inverse Fourier transformation, is the desired source reconstruction.
Date: June 1, 1977
Creator: Perez-Mendez, V.; Chang, L. T.; Lenahan, J. P. & Macdonald, B.
Partner: UNT Libraries Government Documents Department

Nuclear Medicine Program progress report, quarter ending March 31, 1992

Description: We describe the design synthesis and initial animal testing of a new iodine-131-labeled triglyceride analogue for the potential evaluation of clinical pancreatic insufficiency. The new agent is 1,2-dipalmitoyl-3-((15-p-iodophenyl)pentadecanoyl) rac-glycerol(1,2-Pal-3-IPPA). Following oral administration of the iodine-125-labeled agent to rats, 34.5+8.8% of the administered activity was excreted in the urine within one day, demonstrating that radioiodinated IPPA is absorbed in the intestine after release from the triglyceride by pancreatic lipase. The final catabolic product of IPPA is then conjugated and excreted via the urinary bladder. Urine analysis following oral administration of this new agent to patients may thus be a new, simple method for the clinical evaluation of various gastrointestinal diseases. The synthesis and the initial biological evaluation of the 3R-isomer of ({sup 125}I)IQNP are also described.
Date: July 1, 1992
Creator: Knapp, F. F. Jr.; Ambrose, K. R.; Callahan, A. P.; McPherson, D. W.; Mirzadeh, S.; Hasan, A. et al.
Partner: UNT Libraries Government Documents Department

The theoretical basis and clinical methodology for stereotactic interstitial brain tumor irradiation using iododeoxyuridine as a radiation sensitizer and samarium-145 as a brachytherapy source

Description: High grade astrocytomas have proven resistant to all conventional therapy. A technique to produce radiation enhancement during interstitial brain tumor irradiation by using a radiation sensitizer (IdUrd) and by stimulation of Auger electron cascades through absorption of low energy photons in iodine (Photon activation) is described. Clinical studies using IdUrd, {sup 192}Ir as a brachytherapy source, and external radiation have produced promising results. Substituting samarium-145 for {sup 192}Ir in this protocol is expected to produce enhanced results. 15 refs.
Date: January 1, 1989
Creator: Goodman, J. H.; Gahbauer, R. A.; Kanellitsas, C.; Clendenon, N. R. (Ohio State Univ., Columbus, OH (USA)); Laster, B. H. & Fairchild, R. G. (Brookhaven National Lab., Upton, NY (USA))
Partner: UNT Libraries Government Documents Department

SPECT assay of radiolabeled monoclonal antibodies

Description: The long-term goal of this research project is to develop methods to improve the utility of single photon emission computed tomography (SPECI) to quantify the biodistribution of monoclonal antibodies (MoAbs) labeled with clinically relevant radionuclides ({sup 123}I, {sup 131}I, and {sup 111}In) and with another radionuclide,{sup 211}At, recently used in therapy. We describe here our progress in developing quantitative SPECT methodology for {sup 111}In and {sup 123}I. We have focused our recent research thrusts on the following aspects of SPECT: (1) The development of improved SPECT hardware, such as improved acquisition geometries. (2) The development of better reconstruction methods that provide accurate compensation for the physical factors that affect SPECT quantification. (3) The application of carefully designed simulations and experiments to validate our hardware and software approaches.
Date: February 1, 1992
Creator: Jaszczak, R. J.
Partner: UNT Libraries Government Documents Department

Comparisons of coded aperture imaging using various apertures and decoding methods. [gamma camera imaging of radionuclides in tissues]

Description: The utility of coded aperture ..gamma.. camera imaging of radioisotope distributions in Nuclear Medicine is in its ability to give depth information about a three dimensional source. We have calculated imaging with Fresnel zone plate and multiple pinhole apertures to produce coded shadows and reconstruction of these shadows using correlation, Fresnel diffraction, and Fourier transform deconvolution. Comparisons of the coded apertures and decoding methods are made by evaluating their point response functions both for in-focus and out-of-focus image planes. Background averages and standard deviations were calculated. In some cases, background subtraction was made using combinations of two complementary apertures. Results using deconvolution reconstruction for finite numbers of events are also given.
Date: July 1, 1976
Creator: Chang, L. T.; Macdonald, B. & Perez-Mendez, V.
Partner: UNT Libraries Government Documents Department

(A clinical trial of neutron capture therapy for brain tumors)

Description: This document briefly describes recent advances in the author's laboratory. Topics described include neutron beam design, high- resolution autoradiography, boronated phenylalanine (BPA) distribution and survival studies in glioma bearing mice, computer- aided treatment planning, prompt gamma boron 10 analysis facility at MITI-II, non-rodent BPA toxicity studies, and preparations for clinical studies.
Date: January 1, 1990
Creator: Zamenhof, R. G.
Partner: UNT Libraries Government Documents Department

Indocyanine green labeled with /sup 123/I for dynamic studies of the hepato-biliary system. [/sup 131/I, /sup 125/I]

Description: This report summarizes the results to develop an iodine-123 labeled agent for dynamic studies of the hepato-biliary system. Iodine-123 is an ideal nuclide for radiopharmaceuticals, because of its short half-life (T/sub /sup 1///sub 2// = 13.3 hr); its decay with a high abundance (83%) of 159 keV photons; and the reduced patient radiation exposure (a factor of 100 less than iodine-131). Indocyanine green, a tricarbanocyanine dye, was introduced by Heseltine and co-workers in 1956, has several characteristics which suggested that iodine-123 labeled ICG might be potentially useful for hepatic functional evaluation. The plasma clearance and biliary excretion kinetics of /sup 123/I-ICG (in dogs) will be compared to /sup 131/I-rose bengal and bromosulphalein labeled with iodine-125.
Date: January 1, 1975
Creator: Lambrecht, R. M.; Ansari, A. N.; Wolf, A. P. & Atkins, H. L.
Partner: UNT Libraries Government Documents Department

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

Correlation of chromosome patterns in human leukemic cells with exposure to chemicals and/or radiation

Description: This project seeks to defining the chromosome segments associated with radiation induced leukemogenesis (treatment-related acute myeloid leukemia, or t-AML). Towards these goals genetic analysis of human chromosomes 5 and 7 continues to investigate correlation of treatment with balanced and unbalanced chromosomal translocations. Progress is being made in cloning the breakpoints in balanced translocations in t-AML, that is to clone the t(9;11) and t(11;19) breakpoints, to clone the t(3;21)(q26;q22) breakpoints and to determine the relationship of these translocations to prior exposure to topoisomerase II inhibitors. 11 figs. 3 figs.
Date: June 1, 1992
Creator: Rowley, J. D.
Partner: UNT Libraries Government Documents Department

Positron emission camera for transverse section tomography

Description: A transverse section tomographic positron camera is discussed for quantitative imaging of the heart in gated studies using positron emitters such as /sup 82/Rb, /sup 68/Ga, and /sup 18/F. The system consists of a circular ring of 288 NaI(Tl) crystals 8 mm x 30 mm x 50 mm. The crystals are read out by coded light pipes that permit complete data transfer with only 72 photomultipliers. This and other features lead to an economic design that permits 6 to 9 mm FWHM over sections having 40 cm diameter. Digital image reconstruction can be performed on a small dedicated computer using known algorithms. The device is applicable for either static or dynamic imaging of the brain and other organs as well as gated images of the heart. The major application is for the detection and understanding of cardiac and cerebral vascular disease and physiology.
Date: December 1, 1975
Creator: Derenzo, S. E.; Zaklad, H. & Budinger, T. F.
Partner: UNT Libraries Government Documents Department

Boron in nuclear medicine: New synthetic approaches to PET and SPECT

Description: This annual progress report describes new methods of incorporation of radioiodine into physiologically active compounds (amphetamines), and the use of organoboranes to labeled radiopharmaceuticals with Oxygen- 15, Nitrogen-13, carbon-11 and fluorine-18. Preclinical studies are also reported on evaluation of butyothiophenones as agents acting at dopaminergic or serotonic synapses.
Date: September 1, 1992
Creator: Kabalka, G. W.
Partner: UNT Libraries Government Documents Department

New imaging systems in nuclear medicine. Technical progress report, October 1, 1976--May 31, 1977

Description: Work carried out on the development of instrumentation and techniques for positron scintigraphy is discussed. Progress in positron imaging instrumentation and applications is detailed. The assembly and initial evaluation of the new multicrystal positron camera, PC-II, has been completed. Images have been obtained in both two and three-dimensions which demonstrate the basic physical properties of the instrument. Successful measurements using transverse section imaging have been carried out on animals and human volunteers. Physiological investigation using PC-II is proceeding. A flexible and accurate computer program has been developed for transverse section reconstruction of data acquired by PC-II. This program makes it possible to reconstruct both the activity distribution and the distribution of absorption. The program has been developed in such a way that it can handle variations in the data collection procedure. Clinical studies using PC-I and PC-II are being carried on in areas of heart, lung and brain.
Date: January 1, 1977
Creator: Brownell, G. L.
Partner: UNT Libraries Government Documents Department

Biological effects of radiation and related biochemical and physical studies. Proposal 3. Metabolic studies in cancer with radioactive isotopes. Progress report, October 1, 1975--September 30, 1976. [Lead]

Description: Separate abstracts were prepared for seven sections of this report that discuss diagnostic techniques using radioisotopes as tracers.
Date: November 12, 1976
Creator: Laughlin, J. S. & Myers, W. P. L.
Partner: UNT Libraries Government Documents Department

Emission computed axial tomography. [Comparison of /sup 99m/Tc with. gamma. camera with /sup 68/Ga and ring of scintillation counters]

Description: Computed transverse section emission tomography using /sup 99m/Tc with the Anger camera is compared to positron annihilation coincident detection using a ring of crystals and /sup 68/Ga. It is concluded that positron computed section imaging has a tenfold increase in sensitivity over multiple-view imaging with the gamma camera which gives multiple sections but requires camera or patient rotation.
Date: October 1, 1976
Creator: Budinger, T. F.; Derenzo, S. E.; Gullberg, G. T.; Greenberg, W. L. & Huesman, R. H.
Partner: UNT Libraries Government Documents Department