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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 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.
Date: January 1, 1992
Partner: UNT Libraries Government Documents Department

Evaluation of structure effects on the pharmacological behavior of radioiodinated phenylpentadecanoic acids

Description: For studying the pharmacokinetic behaviour of fatty acids with different chemical structures four STI-labelled compounds, i.e., the ortho and para STI-isomers of 15-phenylpentadecanoic acid (IPPA) and 3-methyl-15-phenylpentadecanoic acid were prepared and the organ distribution determined in mice. The results show a significant decrease of the maximal heart uptake for the two ortho compounds. Further, the hypothesis of a blocked metabolism as an effect of the US -methylation could not be confirmed. Both US -methylated compounds show a biexponential elimination behavior from the heart. 5 refs., 2 figs.
Date: January 1, 1986
Creator: Knapp, F.F. Jr.; Goodman, M.M.; Machulla, H.J.; Knust, E.J.; Kartje, M. & Vyska, K.
Partner: UNT Libraries Government Documents Department

Quantitation of the human basal ganglia with Positron Emission Tomography

Description: The accurate measurement of the concentration of a radioisotope in small structures with PET requires a correction for quantitation loss due to the partial volume effect and the effect of scattered radiation. To evaluate errors associated with measures in the human basal ganglia (BG) we have built a unilateral model of the BG that we have inserted in a 20 cm cylinder. The recovery coefficient (RC = measured activity/true activity) for our BG phantom has been measured on a CTI tomograph (model 931-08/12) with different background concentrations (contrast) and at different axial locations in the gantry. The BG was visualized on 4 or 5 slices depending on its position in the gantry and on the contrast used. The RC was 0.75 with no background (contrast equal to 1.0). Increasing the relative radioactivity concentration in the background increased the RC from 0.75 to 2.00 when the contrast was {minus}0.7 (BG < Background). The RC was also affected by the size and the shape of the region of interest (ROI) used (RC from 0.75 to 0.67 with ROI size from 0.12 to 1.41 cm{sup 2}). These results show that accurate RC correction depends not only on the volume of the structure but also on its contrast with its surroundings as well as on the selection of the ROI. They also demonstrate that the higher the contrast the more sensitive to axial positioning PET measurements in the BG are. These data provide us with some information about the variability of PET measurements in small structure like the BG and we have proposed some strategies to improve the reproducibility. 18 refs., 3 figs., 5 tabs.
Date: January 1, 1990
Creator: Bendriem, B.; Dewey, S.L.; Schlyer, D.J.; Wolf, A.P. & Volkow, N.D.
Partner: UNT Libraries Government Documents Department

Age- and sex-related changes in bone mass measured by neutron activation

Description: Total-body calcium (TBCa) measurements have been employed in two basic types of studies. In the first type, serial measurements made on an individual patient are used to trace the time variation in body calcium. In the second type of study, the absolute total body calcium of an individual is determined and compared to a standard or predicted value in order to determine the deficit or excess of calcium. Generally, the standards are derived from data obtained from normal populations and grouped by the parameters of age and sex (mean value denoted TBCa/sub m/). In the study reported in this paper, the clinical usefulness of predicted calcium (TBCa/sub p/) is evaluated. The predicted value (TBCa/sub p/) for an individual is obtained with an algorithm utilizing values of sex and age, height and lean body mass (as derived from /sup 40/K measurement). The latter two components characterize skeletal size and body habitus, respectively. For the study, 133 white women and 71 white men ranging in age from 20 to 80 years were selected from a larger population. Individuals with evidence of metabolic calcium disorders or osteoporosis were excluded. Additionally, the women and men selected were first judged to have total body potassium levels in the normal range. For each age decade, the variance of TBCa values of these individuals, when expressed in terms of TBCa/sub p/, was significantly less than when expressed in terms of TBCa/sub m/. Thus, erroneous conclusions based on Ca deficit in osteoporosis could be drawn for individuals whose height and body size differ markedly from the average, as the variation of their TBCa values often exceeds the variation in the age and sex cohort. Data on a group of osteoporotic women were compared with the normal skeletal baseline values both in terms of the TBCa and the TBCa/sub ...
Date: January 1, 1981
Creator: Cohn, S.H.; Aloia, J.F.; Vaswani, A.N.; Zanzi, I.; Vartsky, D. & Ellis, K.J.
Partner: UNT Libraries Government Documents Department

(New imaging systems in nuclear medicine)

Description: Further progress has been made on improving the uniformity and stability of PCR-I, the single ring analog coded tomograph. This camera has been employed in a wide range of animal studies described below. Data from PCR-I have been used in various image processing procedures. These include motion pictures of dog heart, comparison of PET and MRI image in dog heart and rat brain and quantitation of tumor metabolism in the nude mouse using blood data from heart images. A SUN workstation with TAAC board has been used to produce gated three-dimensional images of the dog heart. The ANALYZE program from the Mayo Clinic has also been mounted on a SUN workstation for comparison of images and image processing. 15 refs., 6 figs.
Date: January 1, 1990
Partner: UNT Libraries Government Documents Department

Microimaging studies of myocardial substrate utilization and perfusion in two models of non-coronary heart disease

Description: We have studied two animal models of non-coronary heart disease. The salt-sensitive Dahl strain hypertensive rats and their genetically matched normotensive controls and the cardiomyopathic BIO 53.58 (CM) strain Syrian hamsters with age and sex-matched RB strain controls. The CM strain hamster seems to be a very good model of human congestive cardiomyopathy and the Dahl strain hypertensive rats have also been found to be good models for studying the effects of hypertension on the myocardium. In our studies we compared the utilization of various metabolic substrates, viz., fatty acids, glucose analogs, and the early distribution of /sup 201/Tl, as an indicator of myocardial flow. The routine studies involving dissection of animals for assaying the radioactivity following the injection of radiopharmaceuticals is not suitable for assessing regional changes in metabolism and flow. The use of quantitative autoradiographic microimaging (ARG) enables the visualization of discrete regional as well as global changes from normal and to quantitate them. This paper describes the methodology and results of these investigations. 14 refs., 5 figs.
Date: January 1, 1987
Creator: Som, P.; Oster, Z.H. & Knapp, F.F. Jr.
Partner: UNT Libraries Government Documents Department

Determination of the lumped constant and the kinetic constants for deoxyglucose and fluorodeoxyglucose in man

Description: If both the time course of the arterial plasma radionuclide concentration and the brain tissue radionuclide concentrations are known, it is possible to calculate the kinetic constants (k/sub 1/*, k/sub 2/*, k/sub 3/*, k/sub 4/*) of the glucose analogue. In a series of male subjects, arterial blood samples were obtained at frequent intervals immediately following the bolus administration of /sup 18/F-FDG and then at less frequent intervals for up to 5 hours after the radionuclide administration. The tissue time course was obtained by making positron emission tomographic scans every three minutes for 30 minutes and then at less frequent intervals for 5 hours. These images were used to construct the time course of /sup 18/F activity in gray and white matter structures. Using these values for the lumped constants and the kinetic constants, the values obtained for the global metabolic rate for glucose in two series of young male subjects were 4.99 +- 0.23 and 5.55 +- 0.37 mg/100 g/min when /sup 11/C-DG and /sup 18/F-FDG were used as tracers respectively.
Date: January 1, 1985
Creator: Greenberg, J.H.; Reivich, M.; Alavi, A.; Wolf, A.; Fowler, J.; Russell, J. et al.
Partner: UNT Libraries Government Documents Department

Copper-67 labeled porphyrin localization in inflamed tissues

Description: A series of experiments compared the uptake of 5,10,15,20-tetrakis(4-carboxyphenyl) porphinato (/sup 67/Cu) copper(II), /sup 67/CuTCPP, by the lymph nodes of inflamed and two sets or control rats. The results demonstrate that /sup 67/CuTCPP localizes in greater concentration in inflamed lymph nodes than in noninflamed control lymph nodes. This enhanced uptake of /sup 67/CuTCPP by inflamed lymph nodes was 3.6 times greater than was the uptake by control lymph nodes. A time course study demonstrated that the uptake of /sup 67/CuTCPP inflamed lymph nodes reached the maximum level by 24 hours post-injection of /sup 67/CuTCPP and remained constant throughout the 96 hours examined. It was also found that the uptake of /sup 67/CuTCPP by inflamed lymph nodes was not exclusively dependent upon an increase in the weight of inflamed lymph nodes. These studies show that /sup 67/CuTCPP has potential as a lymphoscintigraphy agent. 29 refs., 5 figs., 1 tab.
Date: January 1, 1989
Creator: Cole, D.A.; Mercer-Smith, J.A.; Norman, J.K.; Bullington, K.P.; Roberts, J.C. & Lavellee, D.K.
Partner: UNT Libraries Government Documents Department

Synthesis and biological evaluation of (E)-19-iodo-3,3-dimethyl-18-nonadecenoic acid, a new dimethyl-branched long-chain fatty acid to evaluate regional myocardial fatty acid uptake

Description: The synthetic method for the preparation of (E)-19-iodo-3,3-dimethyl-18-nonadecenoic acid (DMIVN) involved introduction of substituents into the 2- and 5-positions of a thiophene ring followed by sulfur extrusion of a 2,5-dialkyl thiophene derivative to provide a key 3,3-dimethyl-branched fatty acid intermediate, 17-iodo-3,3-dimethylheptadecanoic acid. Myocardial subcellular distribution studies of the /sup 125/I-labeled DMIVN in fasted rats showed a higher association of radioactivity with the microsomes when compared to the results obtained with the 19-carbon straight chain analogue. With the nonfasted rats the distribution profiles of the two analogues showed differences that seemed to correlate with the differences in myocardial retention that fasting and feeding can induce. 5 refs., 3 figs., 2 tabs.
Date: January 1, 1986
Creator: Goodman, M.M.; Ambrose, K.R.; Neff, K.H. & Knapp, F.F. Jr.
Partner: UNT Libraries Government Documents Department

Distribution of sulfhydryl boranes in mice and rats

Description: The distribution of boron in mice bearing transplanted Harding-Passey melanomas after rapid and slow administration of monomer were studied. Thin layer chromatographic analysis of the corresponding infusion solution revealed a slow-moving principal band that was later shown to correspond to Na/sub 4/B/sub 24/H/sub 22/S/sub 2/, the dimer of Na/sub 2/B/sub 12/H/sub 11/SH. It was found that while monomer and chemically synthesized dimer yielded similar boron concentrations when they were given rapidly intraperitoneally to mice, the dimer yielded higher boron concentrations in mouse melanoma and higher melanoma-blood boron concentration when each was infused slowly intraperitoneally for 8 to 9 days. Studies have been started on the uptake of dimer into an intracerebrally implanted rat glioma. Boron levels in the rat glioma and in the mouse melanoma from slow intraperitoneal infusion of proportionately comparable amounts of dimer, are similar. However, after these slow infusions boron levels in rat blood are about as high as boron levels in rat brain tumor. 6 refs., 1 fig., 4 tabs.
Date: January 1, 1986
Creator: Slatkin, D.N.; Micca, P.L.; Laster, B.H. & Fairchild, R.G.
Partner: UNT Libraries Government Documents Department

ROC (Receiver Operating Characteristics) study of maximum likelihood estimator human brain image reconstructions in PET (Positron Emission Tomography) clinical practice

Description: This paper will report on the progress to date in carrying out Receiver Operating Characteristics (ROC) studies comparing Maximum Likelihood Estimator (MLE) and Filtered Backprojection (FBP) reconstructions of normal and abnormal human brain PET data in a clinical setting. A previous statistical study of reconstructions of the Hoffman brain phantom with real data indicated that the pixel-to-pixel standard deviation in feasible MLE images is approximately proportional to the square root of the number of counts in a region, as opposed to a standard deviation which is high and largely independent of the number of counts in FBP. A preliminary ROC study carried out with 10 non-medical observers performing a relatively simple detectability task indicates that, for the majority of observers, lower standard deviation translates itself into a statistically significant detectability advantage in MLE reconstructions. The initial results of ongoing tests with four experienced neurologists/nuclear medicine physicians are presented. Normal cases of {sup 18}F -- fluorodeoxyglucose (FDG) cerebral metabolism studies and abnormal cases in which a variety of lesions have been introduced into normal data sets have been evaluated. We report on the results of reading the reconstructions of 90 data sets, each corresponding to a single brain slice. It has become apparent that the design of the study based on reading single brain slices is too insensitive and we propose a variation based on reading three consecutive slices at a time, rating only the center slice. 9 refs., 2 figs., 1 tab.
Date: October 1, 1990
Creator: Llacer, J.; Veklerov, E.; Nolan, D. (Lawrence Berkeley Lab., CA (USA)); Grafton, S.T.; Mazziotta, J.C.; Hawkins, R.A. et al.
Partner: UNT Libraries Government Documents Department

Positron-emitting radioligands for imaging neuroleptic receptors

Description: A series of /sup 18/F-labeled butyrophenones (benperidol, haloperidol, spiroperidol and N-methylspiroperidol) were evaluated in baboons and rats with respect to potential utility as radioligands for studying neuroleptic receptors in the living human brain by positron emission tomography. These compounds were administered to baboons, and the radioactivity distributions to the striatum, and to the cerebellum were determined by PET at times up to 8 hours after isotope injection. 4 refs. (DT)
Date: January 1, 1985
Creator: Arnett, C.D.; Fowler, J.S.; Wolf, A.P.; Shiue, C.Y. & Logan, J.
Partner: UNT Libraries Government Documents Department

(Non-invasive evaluation of the cardiac autonomic nervous system by PET)

Description: The proposed research addresses the development, validation and application of cardiac PET imaging techniques to characterize the autonomic nervous system of the heart. PET technology has significantly matured over the last two decades. Instrument design, image processing and production of radiochemical compounds have formed an integrative approach to provide a powerful and novel imaging modality for the quantitative in vivo evaluation of the autonomic nervous system of the heart. Animal studies using novel tracers for the sympathetic and parasympathetic nerve terminals will be employed to characterize the functional integrity of nerve terminals. This work will be complemented by the development of agents which bind to postsynaptic receptor sites. The combined evaluation of presynaptic and postsynaptic neuronal function will allow a unique characterization of neuronal function. Initial development in animal studies will be followed by feasibility studies in humans. These studies are designed to test sophisticated imaging protocols in the human heart and validate the scintigraphic findings with independent markers of autonomic innervation. Subsequent clinical application in various cardiac diseases is expected to provide new insights into the neuropathophysiology of the heart.
Date: January 1, 1992
Partner: UNT Libraries Government Documents Department

Medical application of in vivo neutron activation analysis

Description: The clinical usefulness of total body neutron activation analysis (TBNAA) was clearly established at an IAEA panel meeting in Vienna in 1972. It is best demonstrated by the studies involving the measurement of total-body calcium. This measurement provides data useful for the diagnosis and management of metabolic bone disorders. It should be emphasized, however, that while most of the applications to date have involved calcium and phosphorus, the measurement of sodium, chlorine and nitrogen also appear to be useful clinically. Total-body calcium measurements utilizing TBNAA have been used in studies of osteoporosis to establish absolute and relative deficits of calcium in patients with this disease in comparison to a normal contrast population. Changes in total-body calcium (skeletal mass) have also been useful for quantitating the efficacy of various therapies in osteoporosis. Serial measurements over periods of years provide long-term balance data by direct measurement with a higher precision (+- 2%) than is possible by the use of any other technique. In the renal osteodystrophy observed in patients with renal failure, disorders of both calcium and phosphorus, as well as electrolyte disturbances, have been studied. The measure of total-body levels of these elements gives the clinician useful data upon which to design dialysis therapy. The measurement of bone changes in endocrine dysfunction has been studied, particularly in patients with thyroid and parathyroid disorders. In parathyroidectomy, the measurement of total-body calcium, post-operatively, can indicate the degree of bone resorption. Skeletal metabolism and body composition in acromegaly and Cushing's disease have also been investigated by TBNAA. Levels of cadmium in liver and kidney have also been measured in-vivo by prompt-gamma neutron activation and associated with hypertension, emphysema and cigarette smoking.
Date: January 1, 1978
Creator: Cohn, S.H.; Ellis, K.J.; Vartsky, D.; Zanzi, I. & Aloia, J.F.
Partner: UNT Libraries Government Documents Department

Radiolabeled porphyrin versus gallium-67 citrate for the detection of human melanoma in athymic mice

Description: We performed the biodistribution and imaging studies of /sup 111/In and /sup 67/Ga labeled tetra(4-N-methylpyridyl) porphine, (T4NMPYP), and compared it to that of /sup 67/Ga citrate in athymic mice bearing a human melanoma xenograft. The biodistribution results of both /sup 111/In and /sup 67/Ga labeled T4NMPYP (3, 6, 24, and 48 hours) were similar but differed from that of /sup 67/Ga citrate (48 hours). The optimum tumor uptake of both radiolabeled porphyrins was at 6 hours postinjection and was lower than the tumor uptake of /sup 67/Ga citrate at 48 hours postinjection. Kidney was the only organ showing higher uptake of radiolabeled porphyrin compared to that of /sup 67/Ga citrate. The imaging studies performed with /sup 111/In T4NMPYP and /sup 67/Ga citrate correspond to the biodistribution results. Osteomyelitis present in one mouse showed good localization of /sup 111/In T4NMPYP. 15 refs., 3 figs., 5 tabs.
Date: January 1, 1987
Creator: Maric, N.; Chan, S. Ming; Hoffer, P.B. & Duray, P.
Partner: UNT Libraries Government Documents Department

Comparison of total-body calcium with radiographic and photon absorptiometry measurement of appendicular bone mineral content. [Comparison of findings in patients with primary osteoporosis and healthy marathon runners]

Description: Two groups of investigators utilized three techniques for evaluating bone mineral mass. In one institution, total-body calcium by total body neutron activation analysis, and bone mineral content of the radius by photon absorptiometry were measured concomitantly. In the other institution, the mean bone mineral content of the three inner phalanges of the left hand was measured by radiographic absorptiometry. These techniques were applied to two groups of subjects: 16 patients with primary osteoporosis and 14 healthy marathon runners. The higher correlation found in osteoporotic patients may be related to the diffuse nature of this condition and to differences in the distribution of skeletal mass in the marathon runners.
Date: January 1, 1978
Creator: Zanzi, I.; Colbert, C.; Bachtell, R.; Thompson, K.; Aloia, J. & Cohn, S.
Partner: UNT Libraries Government Documents Department

Nuclear Medicine Program progress report for quarter ending March 31, 1993

Description: We have exploring the possibility of measuring urinary radioactivity as an index of pancreatic lipase activity after oral administration of a new triglyceride containing a radioactive iodine-1 25-labeled fatty acid moiety. The new agent, 1,2-dipalmitoyl-3[15-(p-iodophenyl)pentandecan-l-oyl]-racglycerol (1,2-Pal-3-IPPA), was prepared by the thallation-iodide displacement method. Following oral gavage of the radioiodinated triglyceride to rats, about 30% of the administered activity was excreted in 24 hours in the urine. In normal human controls an higher urinary excretion (of about 75% was observed. In this report, we describe an evaluation of the metabolites excreted in the urine and the chemical species stored in adipose from rats. The urine activity co-chromatographed with hippuric acid by TLC indicating conjugation of the IPPA metabolites. Release of the acidic components from the conjugated excretory products by acid hydrolysis of the urine provided the radioactive acidic IPPA metabolites. Analysis of the Folch extracts of fat samples from rats demonstrated that the radioactive components co-chromatographed In the triglyceride region. Recent studies in patients with compromised pancreatic exocrine function have demonstrated significantly decreased 24 hr. urinary excretion of about 25%, following oral administration of [1 -1 31]-1,2-Pal-3-IPPA. Thus, urine analysis after oral administration of [I -1 31]-1,2-Pal-3-IPPA may be a simple, non-invasive tool for the clinical evaluation of various diseases involving dietary fat digestion.
Date: April 1, 1993
Creator: Knapp, F.F. Jr.; Ambrose, K.R.; Beets, A.L.; Callahan, A.P.; McPherson, D.W.; Mirzadeh, S. et al.
Partner: UNT Libraries Government Documents Department

Nuclear resonance fluorescence: new technique for in vivo iron determination in man

Description: A technique for the measurement of body iron stores utilizing nuclear resonant scattering of gamma-rays has been developed. 847keV photons emitted from a gaseous /sup 56/MnCl/sub 2/ source are resonantly scattered from /sup 56/Fe present in the liver and are detected by two large volume Ge(Li) detectors. Due to the very narrow resonance of the absorption cross section the technique is very specific to the element under investigation. The spatial uniformity of activation, the sensitivity of the detection system and the limits of detection have been investigated. Measurements were made of liver of a man-like phantom. The sensitivity and the limit of detection obtained for the NRS technique developed in this study are adequate for detection of iron in livers of normal individuals and are certainly sufficient for livers of persons with iron overload.
Date: January 1, 1979
Creator: Vartsky, D.; Ellis, K.J. & Cohn, S.H.
Partner: UNT Libraries Government Documents Department

Radiation dose estimates for copper-64 citrate in man

Description: Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. We have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiation. 5 refs., 3 tabs.
Date: January 1, 1985
Creator: Crook, J.E.; Carlton, J.E.; Stabin, M. & Watson, E.
Partner: UNT Libraries Government Documents Department

New radiohalogenated alkenyl tellurium fatty acids

Description: Radiolabeled long-chain fatty acids have diagnostic value as radiopharmaceutical tools in myocardial imaging. Some applications of these fatty acids are limited due to their natural metabolic degradation in vivo with subsequent washout of the radioactivity from the myocardium. The identification of structural features that will increase the myocardial residence time without decreasing the heart uptake of long-chain fatty acids is of interest. Fatty acids containing the tellurium heteroatom were the first modified fatty acids developed that show unique prolonged myocardial retention and low blood levels. Our detailed studies with radioiodinated vinyliodide substituted tellurium fatty acids demonstrate that heart uptake is a function of the tellurium position. New techniques of tellurium and organoborane chemistry have been developed for the synthesis of a variety of radioiodinated iodoalkenyl tellurium fatty acids. 9 refs., 3 figs., 2 tabs.
Date: January 1, 1987
Creator: Srivastava, P.C.; Knapp, F.F. Jr. & Kabalka, G.W.
Partner: UNT Libraries Government Documents Department

Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography. [Dogs]

Description: While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography (/sup 13/N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique.
Date: June 1, 1980
Creator: Schelbert, H.R. & Phelps, M.E.
Partner: UNT Libraries Government Documents Department

Nuclear Medicine Program progress report for quarter ending September 30, 1991

Description: Rat tissue distribution properties of IQNP,'' a new radioiodinated cholinergic-muscarinic receptor antagonist, are described. IQNP is the acronym for 1-azabicyclo(2.2.2)oct-3-yl {alpha}-hydroxy-{alpha}-phenyl-{alpha}(1-iodo-1-propen-3-yl) acetate, which is an analogue of the QNB muscarinic antagonist in which the p-iodophenyl moiety has been replaced with the 1-iodo-1-propen-3-yl moiety. The radioiodinated IQNP analogue is easier to prepare in much higher yields than QNB and is thus a candidate for the evaluation of muscarinic receptors by external imaging techniques. Studies in rats demonstrated that IQNP shows high uptake in those cerebral regions rich in muscarinic receptors QNB-treatment of rats either 1 h before (pre) or 2 h after (post) administration of radioiodinated IQNP resulted in significant displacement or blocking of cerebral specific IQNP uptake (% dose/gm) in the cortex and striatum. These studies demonstrate that IQNP has specificity for the cholinergic-muscarinic receptor and is a good candidate for further studies. Also during this period, several agents developed in the ORNL Nuclear Medicine Program were supplied to Medical Cooperative Programs for collaborative studies including the iodine-125-labeled BMIPP and DMIPP fatty acid analogues and the IPM antibody labeling agent. Tin-117m and gold-199 were produced in the ORNL High Flux Isotope Reactor (HFIR) and supplied to the OHER-supported program in the Medical Department at Brookhaven National Laboratory to aid in their research until the re-start of the High Flux Brookhaven Reactor.
Date: February 1, 1992
Creator: Knapp, F.F. Jr.; Ambrose, K.R.; Callahan, A.P.; McPherson, D.W.; Mirzadeh, S.; Srivastava, P.C. et al.
Partner: UNT Libraries Government Documents Department

Design and evaluation of radiotracers for determination of regional cerebral blood flow with PET

Description: The tracer kinetics of 4-Fluoro(/sup 18/F)-, 4-Bromo(/sup 82/Br)- and 4-Iodo(/sup 125/I)-antipyrine and /sup 15/O-water were compared in a cat or baboon animal model. First-pass cerebral extraction and clearance with alterations in PaCO/sub 2/ were measured for whole brain. The Renkin/Crone model was used to evaluate brain capillary permeability-surface area product for 4-/sup 18/FAP in cats. Positron-emission-tomographic measurements required development of an instrument and technique for control of the arterial concentration of the radiotracer as a ramp function, so that tracer concentration changes due to radioactive decay or altered physiological processes could be accurately described with PET. Pharmacokinetic and tissue-distribution studies in cats were used to determine dosimetry for 4-/sup 18/FAP. 4-Bromoantipyrine labeled with /sup 78/Br (t = 6.5 m) is suggested as a tracer for determination of rCBF with PET.
Date: January 1, 1982
Creator: Lambrecht, R.M.; Duncan, C.C. & Shiue, C.Y.
Partner: UNT Libraries Government Documents Department

Positron Emission Tomography (PET)

Description: Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs.
Date: January 1, 1990
Creator: Welch, M. J.
Partner: UNT Libraries Government Documents Department