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Sample records for brain positron emission

  1. Imaging of brain activity by positron emission tomography

    International Nuclear Information System (INIS)

    Brain function is associated with regional energy metabolism and blood flow increase. Such brain activity is visualized by using external scintigraphy. Positron emission tomography (PET) is the currently available most superior technique, allowing three-dimensional imaging of subtle blood flow. In this article, imaging methods and application of PET are discussed in terms of the following items: (1) measurement of cerebral glucose consumption, (2) PET in persons with visual impairment, (3) association between brain function and regional cerebral blood flow, (4) measurement of cerebral blood flow, (5) method for decreasing noise in PET imaging, (6) anatomic standardization of PET images, and (7) speech load and regional cerebral activity images. (N.K.)

  2. Studies of the brain cannabinoid system using positron emission tomography

    International Nuclear Information System (INIS)

    Studies using radiolabeled psychoactive drugs in conjunction with positron emission tomography (PET) have permitted the imaging of binding sites in the human brain. Similar studies of marijuana have been hampered by the unsuitability of radiolabeled THC for PET studies, and the current unavailability of other in vivo imaging agents for cannabinoid receptors. Recent developments in medicinal chemistry suggest that a PET radiotracer for cannabinoid receptors will soon become available. This chapter briefly reviews these developments, together with the results of PET studies of the effects of marijuana and other abused drugs on brain metabolism. It also reviews PET studies of cocaine binding sites, to demonstrate the kind of investigations that will be possible when a cannabinoid receptor PET radioligand becomes available

  3. Studies of the brain cannabinoid system using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gatley, S.J.; Volkow, N.D.

    1995-10-01

    Studies using radiolabeled psychoactive drugs in conjunction with positron emission tomography (PET) have permitted the imaging of binding sites in the human brain. Similar studies of marijuana have been hampered by the unsuitability of radiolabeled THC for PET studies, and the current unavailability of other in vivo imaging agents for cannabinoid receptors. Recent developments in medicinal chemistry suggest that a PET radiotracer for cannabinoid receptors will soon become available. This chapter briefly reviews these developments, together with the results of PET studies of the effects of marijuana and other abused drugs on brain metabolism. It also reviews PET studies of cocaine binding sites, to demonstrate the kind of investigations that will be possible when a cannabinoid receptor PET radioligand becomes available.

  4. Non-oncological positron emission tomography (PET): brain imaging

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) allows evaluation of the central nervous system function. Imaging of regional cerebral blood flow and metabolism, and of several neurotransmission systems may be obtained using PET. PET quantification is accurate and has good test-retest reliability. For research purposes, PET has been used to study brain physiology, to explore neurological and psychiatric diseases pathophysiology and for the new drugs research and development. F.D.G. is the only PET radioligand with clinical application. Following criteria of evidence-based medicine, the clinical indications of F.D.G.-PET are: evaluation of treated gliomas, pre surgical study of partial refractory epilepsy and diagnosis of Alzheimer's disease when it is impossible to differentiate clinically from fronto-temporal dementia

  5. Anaesthesia for positron emission tomography scanning of animal brains.

    Science.gov (United States)

    Alstrup, Aage Kristian Olsen; Smith, Donald F

    2013-01-01

    Positron emission tomography (PET) provides a means of studying physiological and pharmacological processes as they occur in the living brain. Mice, rats, dogs, cats, pigs and non-human primates are often used in studies using PET. They are commonly anaesthetized with ketamine, propofol or isoflurane in order to prevent them from moving during the imaging procedure. The use of anaesthesia in PET studies suffers, however, from the drawback of possibly altering central neuromolecular mechanisms. As a result, PET findings obtained in anaesthetized animals may fail to correctly represent normal properties of the awake brain. Here, we review findings of PET studies carried out either in both awake and anaesthetized animals or in animals given at least two different anaesthetics. Such studies provide a means of estimating the extent to which anaesthesia affects the outcome of PET neuroimaging in animals. While no final conclusion can be drawn concerning the 'best' general anaesthetic for PET neuroimaging in laboratory animals, such studies provide findings that can enhance an understanding of neurobiological mechanisms in the living brain. PMID:23349451

  6. Study of brain metabolism using positron emission computed tomography

    International Nuclear Information System (INIS)

    Positron emission tomography permits the three-dimensional regional measurement of metabolism and blood flow in the brain. For the determination of cerebral metabolic rates of glucose by PET 18fluordeoxyglucose is usually applied: cerebral metabolic rate of glucose was found to be 36 to 47 μmol/100 g/min in the grey matter and 23 to 29 μmol/100 g/min in the white matter of normal volunteers. During physiologic activation metabolic rate of glucose is increased in the respective brain areas in relation to the strength and complexity of the stimulation. In patients suffering from ischaemic stroke glucose metabolism is markedly decreased within the infarction. Additonally, glucose metabolism is reduced by 20% in morphologically intact areas of the homolateral cortex, in the basal ganglia, in the cortical area contralateral to the infarction and in the contralateral cerebellum. This remote reduction of glucose utilization is probably caused by functional inactivation of these brain structures; it could be responsible for the diffuse organic syndrome in stroke victims not caused by the focal lesion. In patients suffering from dementia of the multi-infarct type and of the Alzheimer type glucose metabolism is reduced; the lesions in Alzheimer cases are most prominent in partietal and frontal cortical areas. In Chorea Huntington cases glucose metabolism is primarily disturbed in the striate, especially in the caudate nucleus; in these cases the metabolic disturbance can be detected earlier than the atrophy in computed tomograms. Disturbances of glucose and oxygen utilization are not necessary causes, but may also be sequelae od functional impairment. Additional information on pathogentic mechanisms may be obtained by the investigation of the protein synthesis. (orig.)

  7. Brain Imaging with Positron Emission Tomography: Quantification and Biomedical Applications in Alzheimer's Disease and Brain Tumors

    OpenAIRE

    Wardak, Mirwais

    2013-01-01

    Positron emission tomography (PET) is a unique and powerful imaging technique that is used to visualize and quantify various biological processes in living subjects in health and disease. PET imaging can also provide biological information for the assessment of therapies. In this dissertation, we will cover three projects that utilize the quantitative capability of PET for studying two neurological disorders: Alzheimer's disease and brain tumors.One of the goals in PET imaging is to produce...

  8. Axial positrons emission tomography: from mouse to human brain imaging

    International Nuclear Information System (INIS)

    Positrons emission tomography is a nuclear imaging technics using nuclear decays. It is used both in clinical and preclinical studies. The later requires the use of small animals such as the mouse. The objective is to obtain the best signal with the best spatial resolution. Yet, a weight ratio between humans and mice indicates the need of a sub-millimeter resolution. A conventional scanner is based on detection modules surrounding the object to image and arranged perpendicularly. This implies a strong relationship between efficiency and spatial resolution. This work focuses on the axial geometry in which detection modules are arranged parallel to the object. This limits the relationship between the figures of merit, leading to both high spatial resolution and efficiency. The simulations of prototypes showed great perspectives in term of sub-millimeter resolution with efficiencies of 15 or 40% according to the scanner's axial extension. These results indicate great perspectives for both clinical and preclinical imaging. (author)

  9. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    International Nuclear Information System (INIS)

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions

  10. Measurement of human blood brain barrier integrity using 11C-inulin and positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) using 11C-inulin was demonstrated to be applicable to the clinical measurement of blood brain barrier permeability and cerebral interstitial fluid volume. Kinetic data were analyzed by application of a two compartment model, in which blood plasma and interstitial fluid spaces constitute the compartments. The blood activity contribution was subtracted from the PET count with the aid of the 11CO inhalation technique. The values we estimated in a human brain were in agreement with the reported values obtained for animal brains by the use of 14C-inulin. (orig.)

  11. Novel positron emission tomography radiotracers in brain tumor imaging

    OpenAIRE

    Maria Mathew D′Souza; Rajnish Sharma; Madhavi Tripathi; Puja Panwar; Abhinav Jaimini; Anupam Mondal

    2011-01-01

    Although [18F] 2-fluoro-2-deoxy-D-glucose (FDG) is the most widely used radiopharmaceutical the world over, it is not the ideal tracer for brain imaging, owing to its high physiological cortical uptake and lack of specificity. This has paved the way for the introduction of several novel radiotracers, each with their own inherent strengths and limitations. We present the insights gained from the use of these radiotracers at our institution.

  12. Novel positron emission tomography radiotracers in brain tumor imaging

    Directory of Open Access Journals (Sweden)

    Maria Mathew D′Souza

    2011-01-01

    Full Text Available Although [18F] 2-fluoro-2-deoxy-D-glucose (FDG is the most widely used radiopharmaceutical the world over, it is not the ideal tracer for brain imaging, owing to its high physiological cortical uptake and lack of specificity. This has paved the way for the introduction of several novel radiotracers, each with their own inherent strengths and limitations. We present the insights gained from the use of these radiotracers at our institution.

  13. Positron emission tomography studies in the normal and abnormal ageing of human brain

    International Nuclear Information System (INIS)

    Until recently, the investigation of the neurophysiological correlates of normal and abnormal ageing of the human brain was limited by methodological constraints, as the technics available provided only a few parameters (e.g. electroencephalograms, cerebral blood flow) monitored in superficial brain structures in a grossly regional and poorly quantitative way. Lately several non invasive techniques have been developed which allow to investigate in vivo both quantitatively and on local basis a number of previously inaccessible important aspects of brain function. Among these techniques, such as single photon emission tomography imaging of computerized electric events, nuclear magnetic resonance, positron emission tomography stands out as the most powerful and promising method since it allows the in vivo measurement of biochemical and pharmacological parameters

  14. Patterns of brain activity in normals and schizophrenics with positron emission tomography

    International Nuclear Information System (INIS)

    The authors investigated the functional interaction among brain areas under baseline and upon activation by a visual task to compare the response of normal subjects from the ones of chronic schizophrenics. Cerebral metabolic images were obtained on twelve healthy volunteers an eighteen schizophrenics with positron emission tomography and 11-C-Deoxyglucose. Correlation coefficients among the relative metabolic values (region of interest divided by the average of whole brain gray matter) of 11 brain regions; frontal, parietal, temporal and occipital left and right lobes, left and right basal ganglia and thalamus were computed for the baseline and for the task. Under baseline, normals showed more functional correlations than schizophrenics. Both groups showed a thalamo-occipital (positive) and thalamo-frontal (negative) interaction. The highest correlations among homologous brain areas were the frontal, occipital and basal ganglia

  15. Brain energy metabolism and dopaminergic function in Huntington's disease measured in vivo using positron emission tomography

    International Nuclear Information System (INIS)

    A 48-year-old man with typical Huntington's disease was investigated with computed tomography (CT) and positron emission tomography. Regional cerebral blood flow, oxygen extraction, oxygen and glucose utilization, L-Dopa uptake, and dopamine (D2) receptor binding were measured using several positron-labelled tracers. CT showed slight atrophy of the head of caudate but no cortical atrophy, although distinct frontal lobe dysfunction was present on psychometric testing. Oxygen and glucose metabolism and cerebral blood flow were decreased in the striata and to a lesser extent in frontal cortex. Cerebral blood flow was in the low normal range throughout the remainder of the brain. A normal metabolic ratio was found in all regions, since the changes in glucose utilization paralleled those in oxygen consumption. The capacity of the striatum to store dopamine as assessed by L-[18F]-fluorodopa uptake was normal, but dopamine (D2) receptor binding was decreased when compared to normal subjects

  16. Brain dopaminergic system changes in drug addiction: a review of positron emission tomography findings.

    Science.gov (United States)

    Hou, Haifeng; Wang, Chunyan; Jia, Shaowei; Hu, Shu; Tian, Mei

    2014-10-01

    Dopamine (DA) is considered crucial for the rewarding effects of drugs of abuse, but its role in addiction remains unclear. Positron emission tomography (PET) is the first technology used for in vivo measurement of components of the dopaminergic system in the human brain. In this article, we review the major findings from PET imaging studies on the involvement of DA in drug addiction, including presynaptic DA synthesis, vesicular monoamine transporter 2, the DA transporter, and postsynaptic DA receptors. These results have corroborated the role of DA in addiction and increased the understanding of its underlying mechanisms. PMID:25260796

  17. Nicotine Blocks Brain Estrogen Synthase (Aromatase): In Vivo Positron Emission Tomography Studies in Female Baboons

    International Nuclear Information System (INIS)

    Cigarette smoking and nicotine have complex effects on human physiology and behavior, including some effects similar to those elicited by inhibition of aromatase, the last enzyme in estrogen biosynthesis. We report the first in vivo primate study to determine whether there is a direct effect of nicotine administration on brain aromatase. Brain aromatase availability was examined with positron emission tomography and the selective aromatase inhibitor (11C)vorozole in six baboons before and after exposure to IV nicotine at .015 and .03 mg/kg. Nicotine administration produced significant, dose-dependent reductions in (11C)vorozole binding. The amygdala and preoptic area showed the largest reductions. Plasma levels of nicotine and its major metabolite cotinine were similar to those found in cigarette smokers. Nicotine interacts in vivo with primate brain aromatase in regions involved in mood, aggression, and sexual behavior.

  18. Nicotine Blocks Brain Estrogen Synthase (Aromatase): In Vivo Positron Emission Tomography Studies in Female Baboons

    Energy Technology Data Exchange (ETDEWEB)

    Biegon, A.; Biegon, A.; Kim, S.-W.; Logan, J.; Hooker, J.M.; Muench, L.; Fowler, J.S.

    2010-01-12

    Cigarette smoking and nicotine have complex effects on human physiology and behavior, including some effects similar to those elicited by inhibition of aromatase, the last enzyme in estrogen biosynthesis. We report the first in vivo primate study to determine whether there is a direct effect of nicotine administration on brain aromatase. Brain aromatase availability was examined with positron emission tomography and the selective aromatase inhibitor [{sup 11}C]vorozole in six baboons before and after exposure to IV nicotine at .015 and .03 mg/kg. Nicotine administration produced significant, dose-dependent reductions in [{sup 11}C]vorozole binding. The amygdala and preoptic area showed the largest reductions. Plasma levels of nicotine and its major metabolite cotinine were similar to those found in cigarette smokers. Nicotine interacts in vivo with primate brain aromatase in regions involved in mood, aggression, and sexual behavior.

  19. [18F]-labeled 2-methoxyphenylpiperazine derivative as a potential brain positron emission tomography imaging agent

    International Nuclear Information System (INIS)

    This study reports the synthesis and characterization of N-(3-(4-(2-methoxyphenyl)piperazin-1-yl)propyl-4-[18F]fluorobenzamide ([18F]MPP3F). The total reaction time for [18F]MPP3F, including final high-performance liquid chromatography purification, was about 3 h. Typical decay-corrected radiochemical yield was 18.4±3.1%. The radiochemical purity was >98%. Biodistribution in mice showed that [18F]MPP3F is a potential brain imaging agent for positron emission tomography. The brain uptake of [18F]MPP3F was 6.59±0.77% Injected Dose/g at 2 min post-injection time. A brain-to-blood ratio of 3.67 was reached at 15 min after injection.

  20. Positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon (11C), oxygen (15O), and nitrogen (13N) elements. With the tomographic principles of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment. (au) (19 refs.)

  1. Evaluation of blood-brain barrier permeability changes in rhesus monkeys and man using 82Rb and positron emission tomography

    International Nuclear Information System (INIS)

    Dynamic positron tomography of the brain with /sup 82/Rb, obtained from a portable generator [/sup 82/Sr (25 days) - /sup 82/Rb (76 sec)], provides a means of studying blood-brain barrier (BBB) permeability in physiological and clinical investigations. The BBB in rhesus monkeys was opened unilaterally be intracarotid infusion of 3 M urea. This osmotic barrier opening allowed entry into the brain of intravenously administered rubidium chloride. The BBB opening was demonstrated noninvasively using /sup 82/Rb and positron emission tomography and corroborated by the accumulation of /sup 86/Rb in tissue samples. Positron emission tomography studies can be repeated every 5 min and indicate that dynamic tomography or static imaging can be used to study BBB permeability changes induced by a wide variety of noxious stimuli. Brain tumors in human subjects are readily detected because of the usual BBB permeability disruption in and around the tumors

  2. Evaluation of blood--brain barrier permeability changes in rhesus monkeys and man using 82Rb and positron emission tomography

    International Nuclear Information System (INIS)

    Dynamic positron tomography of the brain with 82Rb, obtained from a portable generator [82Sr (25 days) -- 82Rb (76 sec)], provides a means of studying blood-brain barrier (BBB) permeability in physiological and clinical investigations. The BBB in rhesus monkeys was opened unilaterally by intracarotid infusion of 3 M urea. This osmotic barrier opening allowed entry into the brain of intravenously administered rubidium chloride. The BBB opening was demonstrated noninvasively using 82Rb and positron emission tomography and corroborated by the accumulation of 86Rb in tissue samples. Positron emission tomography studies can be repeated every 5 min and indicate that dynamic tomography or static imaging can be used to study BBB permeability changes induced by a wide variety of noxious stimuli. Brain tumors in human subjects are readily detected because of the usual BBB permeability disruption in and around the tumors

  3. Positron Emission Tomography Reveals Abnormal Topological Organization in Functional Brain Network in Diabetic Patients.

    Science.gov (United States)

    Qiu, Xiangzhe; Zhang, Yanjun; Feng, Hongbo; Jiang, Donglang

    2016-01-01

    Recent studies have demonstrated alterations in the topological organization of structural brain networks in diabetes mellitus (DM). However, the DM-related changes in the topological properties in functional brain networks are unexplored so far. We therefore used fluoro-D-glucose positron emission tomography (FDG-PET) data to construct functional brain networks of 73 DM patients and 91 sex- and age-matched normal controls (NCs), followed by a graph theoretical analysis. We found that both DM patients and NCs had a small-world topology in functional brain network. In comparison to the NC group, the DM group was found to have significantly lower small-world index, lower normalized clustering coefficients and higher normalized characteristic path length. Moreover, for diabetic patients, the nodal centrality was significantly reduced in the right rectus, the right cuneus, the left middle occipital gyrus, and the left postcentral gyrus, and it was significantly increased in the orbitofrontal region of the left middle frontal gyrus, the left olfactory region, and the right paracentral lobule. Our results demonstrated that the diabetic brain was associated with disrupted topological organization in the functional PET network, thus providing functional evidence for the abnormalities of brain networks in DM. PMID:27303259

  4. Positron Emission Tomography Reveals Abnormal Topological Organization in Functional Brain Network in Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Qiu eXiangzhe

    2016-05-01

    Full Text Available Recent studies have demonstrated alterations in the topological organization of structural brain networks in diabetes mellitus (DM. However, the DM-related changes in the topological properties in functional brain networks are almost unexplored so far. We therefore used fluoro-D-glucose positron emission tomography (FDG-PET data to construct functional brain networks of 73 DM patients and 91 sex- and age-matched normal controls (NCs, followed by a graph theoretical analysis. We found that both DM patients and NCs had a small-world topology in functional brain network. In comparison to the NC group, the DM group was found to have significantly lower small-world index, lower normalized clustering coefficients and higher normalized shortest path length. Moreover, for diabetic patients, the nodal centrality was significantly reduced in the right rectus, the right cuneus, the left middle occipital gyrus, and the left postcentral gyrus, and it was significantly increased in the orbitofrontal region of the left middle frontal gyrus, the left olfactory region, and the right paracentral lobule. Our results demonstrated that the diabetic brain was associated with disrupted topological organization in the functional PET network, thus providing the functional evidence for the abnormalities of brain networks in DM.

  5. The use of positron emission tomography for the evaluation of choline metabolism in the brain of the rhesus monkey

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) offers an unique opportunity to study regional distribution of different compounds noninvasively. After i.v. injection of substances labelled with short-lived isotopes such as C 11, N 13, 0 15, F 18, or Ga 68, the distribution of the radioactive label is measured as a function of ttime by means of a tomographic technique, based on theaannihilation radiation produced during the process of positron emission. Previously, studies on brain choline metabolism have been performed in small animals using tritium or C 14 isotopes. This paper suggests a possible method for the study of brain Ch-metabolism in vivo in primates usin C 11 - labelled Ch

  6. Positron Emission Tomography (PET Quantification of GABAA Receptors in the Brain of Fragile X Patients.

    Directory of Open Access Journals (Sweden)

    Charlotte D'Hulst

    Full Text Available Over the last several years, evidence has accumulated that the GABAA receptor is compromised in animal models for fragile X syndrome (FXS, a common hereditary form of intellectual disability. In mouse and fly models, agonists of the GABAA receptor were able to rescue specific consequences of the fragile X mutation. Here, we imaged and quantified GABAA receptors in vivo in brain of fragile X patients using Positron Emission Topography (PET and [11C]flumazenil, a known high-affinity and specific ligand for the benzodiazepine site of GABAA receptors. We measured regional GABAA receptor availability in 10 fragile X patients and 10 control subjects. We found a significant reduction of on average 10% in GABAA receptor binding potential throughout the brain in fragile X patients. In the thalamus, the brain region showing the largest difference, the GABAA receptor availability was even reduced with 17%. This is one of the first reports of a PET study of human fragile X brain and directly demonstrates that the GABAA receptor availability is reduced in fragile X patients. The study reinforces previous hypotheses that the GABAA receptor is a potential target for rational pharmacological treatment of fragile X syndrome.

  7. Kinetic modeling of Fe-52/Mn-52m-citrate at the blood-brain barrier by positron emission tomography

    NARCIS (Netherlands)

    Calonder, C; Wurtenberger, PI; Maguire, RP; Pellikka, R; Leenders, KL

    1999-01-01

    The kinetics of iron at the blood-brain barrier of the monkey were studied in vivo using positron emission tomography (PET) and the tracer Fe-52/Mn-52m-citrate. Mn-52m is the beta(+)-emitting daughter nuclide of Fe-52 and therefore contributes to the observed signal and background in the PET images

  8. Positron Emission Tomography (PET) and its application in clinical diagnosis and functional brain organization studies

    International Nuclear Information System (INIS)

    Recent advances in positron emission tomography (PET) and other brain-imaging techniques have made it possible to visualize the working brain while the human subject is thinking, speaking or planning an action. PET provides researches with an opportunity to infer the neuroanatomy of a given function. Subjects either inhale or are injected with a radioactive material that binds to a physiologically active compound in the body. This serves as a tracer of blood flow and metabolic processes that reflect the activation of a given structure by emitting gamma rays which may be detected through a tomograph. PET research has produced findings that extend our knowledge on several important issues such as cerebral representation of language, perception, attention or memory. It has also proven to be an important source of information for clinical diagnosis of various neurological and psychiatric diseases. The present article provides a short review of main achievements in those fields. However, functional brain imaging is not exempt from methodological and theoretical difficulties. The main limitations of the method have been outlined. (author)

  9. Optimised motion tracking for positron emission tomography studies of brain function in awake rats.

    Directory of Open Access Journals (Sweden)

    Andre Z Kyme

    Full Text Available Positron emission tomography (PET is a non-invasive molecular imaging technique using positron-emitting radioisotopes to study functional processes within the body. High resolution PET scanners designed for imaging rodents and non-human primates are now commonplace in preclinical research. Brain imaging in this context, with motion compensation, can potentially enhance the usefulness of PET by avoiding confounds due to anaesthetic drugs and enabling freely moving animals to be imaged during normal and evoked behaviours. Due to the frequent and rapid motion exhibited by alert, awake animals, optimal motion correction requires frequently sampled pose information and precise synchronisation of these data with events in the PET coincidence data stream. Motion measurements should also be as accurate as possible to avoid degrading the excellent spatial resolution provided by state-of-the-art scanners. Here we describe and validate methods for optimised motion tracking suited to the correction of motion in awake rats. A hardware based synchronisation approach is used to achieve temporal alignment of tracker and scanner data to within 10 ms. We explored the impact of motion tracker synchronisation error, pose sampling rate, rate of motion, and marker size on motion correction accuracy. With accurate synchronisation (20 Hz, and a small head marker suitable for awake animal studies, excellent motion correction results were obtained in phantom studies with a variety of continuous motion patterns, including realistic rat motion (<5% bias in mean concentration. Feasibility of the approach was also demonstrated in an awake rat study. We conclude that motion tracking parameters needed for effective motion correction in preclinical brain imaging of awake rats are achievable in the laboratory setting. This could broaden the scope of animal experiments currently possible with PET.

  10. Positron emission tomography.

    Science.gov (United States)

    Hoffman, E J; Phelps, M E

    1979-01-01

    Conventional nuclear imaging techniques utilizing lead collimation rely on radioactive tracers with little role in human physiology. The principles of imaging based on coincidence detection of the annihilation radiation produced in positron decay indicate that this mode of detection is uniquely suited for use in emission computed tomography. The only gamma-ray-emitting isotopes of carbon, nitrogen, and oxygen are positron emitters, which yield energies too high for conventional imaging techniques. Thus development of positron emitters in nuclear medicine imaging would make possible the use of a new class of physiologically active, positron-emitting radiopharmaceuticals. The application of these principles is described in the use of a physiologically active compound labeled with a positron emitter and positron-emission computed tomography to measure the local cerebral metabolic rate in humans. PMID:440173

  11. Catecholaminergic neurotransmission in heart and brain, development of tracers for positron emission tomography

    OpenAIRE

    Langer, Claus Oliver

    2000-01-01

    The catecholamines norepinephrine and its biosynthetic precursor dopamine are two principal neurotransmitters in the human central nervous system (CNS). Moreover, norepinephrine is a major transmitter substance in the peripheral, autonomic nervous system. Positron emission tomography (PET) is a non-invasive imaging technique that uses positron-labeled molecules to image and measure the function of biological processes in vivo. Neuronal catecholaminergic pathways, both in CNS...

  12. Evaluation of various attenuation correction methods for brain imaging in positron emission tomography

    International Nuclear Information System (INIS)

    Corrections for photon attenuation in positron emission tomography (PET) will, in general, affect quantitative accuracy and noise characteristics of the reconstructed images. Each correction approach provides certain advantages as well as disadvantages. The choice of the best method for a particular study depends on the task objective, e.g., lesion detection or quantitation, and limits of acquisition and processing time. In the present study, the following attenuation correction methods have been systematically evaluated for brain imaging with PET: (1) analytical model method; (2) direct transmission measurement method; (3) smoothed transmission data method; (4) reconstructed transmission image method; (5) object contour method; and (6) boundary method. Criteria for evaluating the performance of these methods have been developed in terms of computation efficiency and image quality descriptors such as quantitative accuracy, reconstructed image resolution, and noise characteristics. Effects of total number of transmission counts, total number of emission counts, size of the region of interest, smoothing parameters, reconstruction filters, and object contrast have also been investigated. Based on the results of computer simulation studies, the establishment of a methodology for choosing the best attenuation correction method for a defined purpose, e.g., detecting a 2 cm diameter lesion or quantitating a 4 cm diameter region, has been attempted. This systematic approach has been applied to phantom and in vivo studies. In most cases, the smoothed transmission data method appears to be the best compromise of computation time and image quality

  13. Pathophysiological aspects of malignant brain tumors studied with positron emission tomography

    International Nuclear Information System (INIS)

    To further understand the control of brain tumor fluid balance and pH, the following studies were undertaken. The transport of a water soluble molecule across the brain and tumor capillary endothelium was studied during glucocorticoid and radiation treatment. The brain and brain-tumor acidity (pH) was evaluated as a single measurement in patients receiving a low maintenance dose of glucocorticoid. Transport changes and pH were measured in 61 patients with cerebral tumors using 82Rubidium (82Rb) and 11C-Dimethyloxa-zolidindione (11C-DMO), respectively, and Positron Emission Tomography (PET). Supplementary studies of tumor and contralateral brain blood flow and blood volume using the C15O2/PET and C15O/PET technique, respectively, were included to validate the 82Rb/PET model and obtain further information. A total of 125 PET scans were performed. Supplementary studies were undertaken to estimate delay of blood registration and form distribution of arterial blood isotope activity curves. Blood-to-tumor barrier transport was outlined at baseline and at 6 and 24 hours after the start of glucocorticoid treatment, finding a significant decrease in the transpfort. Radiation treatment (2-6 gray) did not alter the blood-to-tumor barrier transport when restudied within one hour in patients receiving glucocorticoid. The pH in brain tumors was as high as 6.88-7.26, suggesting that tumors are more alkalotic than the normal brain. The permeability surface area product and the permeability coefficient were determined form the 82Rb/PET transport and C15O2/PET flow studies. Baseline permeability values were comparable to the literature values both for 82Rb and potassium. No difference in tissue blood volume was seen between 82Rb/PET and C15O/PET models and was of the same magnitude in the tumor and the contralateral tissue. Aspects of tumor alkalosis, tumor edema production, glucocorticoid edema clearance, and relationship between the anti-edema effect of glucocorticoid and the

  14. 18F-fluorodeoxyglucose positron emission tomography imaging in brain tumours : The Western Australia positron emission tomography/cyclotron service experience

    International Nuclear Information System (INIS)

    Full text: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans in the first 49 patients referred with either possible brain tumour or brain tumour recurrence were reviewed. FDG-PET imaging was reported with reference to anatomical imaging. Based on the report the FDG study was classified as either positive or negative for the presence of tumour. Thirty-eight cases were included in the analysis, 21 having pathological data and 17 with diagnostic clinical follow up. Eleven were excluded, as they had inadequate follow-up data. Of the 21 cases with pathology, 18 were shown to have tumour. In this group there were five false-negative scans and two false-positive PET scans. Seventeen cases were assessed by clinical follow up, nine were considered to have been tumour. There were two false negatives with one false positive. The overall sensitivity, specificity and positive and negative predictive values were 74, 73, 87 and 53% respectively. This is similar to figures previously quoted in published work. Despite relatively limited numbers, the utility of FDG PET imaging in our hands is similar to published reports. With a positive predictive value of 87%, a positive FDG study indicates a high likelihood that there is brain tumour present. A negative study does not exclude the presence of tumour

  15. NMF on positron emission tomography

    DEFF Research Database (Denmark)

    Bödvarsson, Bjarni; Hansen, Lars Kai; Svarer, Claus;

    2007-01-01

    In positron emission tomography, kinetic modelling of brain tracer uptake, metabolism or binding requires knowledge of the cerebral input function. Traditionally, this is achieved with arterial blood sampling in the arm or as shown in (Liptrot, M, et al., 2004) by non-invasive K-means clustering....... We propose another method to estimate time-activity curves (TAC) extracted directly from dynamic positron emission tomography (PET) scans by non-negative matrix factorization (NMF). Since the scaling of the basis curves is lost in the NMF the estimated TAC is scaled by a vector alpha which is...

  16. Reduced cerebral glucose metabolism and increased brain capillary permeability following high-dose methotrexate chemotherapy: a positron emission tomographic study

    International Nuclear Information System (INIS)

    Regional glucose metabolic rate constants and blood-to-brain transport of rubidium were estimated using positron emission tomography in an adolescent patient with a brain tumor, before and after chemotherapy with intravenous high-dose methotrexate. Widespread depression of cerebral glucose metabolism was apparent 24 hours after drug administration, which may reflect reduced glucose phosphorylation, and the influx rate constant for 82Rb was increased, indicating a drug-induced alteration in blood-brain barrier function. Associated changes in neuropsychological performance, electroencephalogram, and plasma amino acid concentration were identified in the absence of evidence of systemic methotrexate toxicity, suggesting primary methotrexate neurotoxicity

  17. Positron emission tomography (PET) studies of dopaminergic/cholinergic interactions in the baboon brain

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, S.L.; Brodie, J.D.; Fowler, J.S.; MacGregor, R.R.; Schlyer, D.J.; King, P.T.; Alexoff, D.L.; Volkow, N.D.; Shiue, C.Y.; Wolf, A.P. (Brookhaven National Lab., Upton, NY (USA))

    1990-01-01

    Interactions between the dopaminergic D2 receptor system and the muscarinic cholinergic system in the corpus striatum of adult female baboons (Papio anubis) were examined using positron emission tomography (PET) combined with (18F)N-methylspiroperidol (( 18F)NMSP) (to probe D2 receptor availability) and (N-11C-methyl)benztropine (to probe muscarinic cholinergic receptor availability). Pretreatment with benztropine, a long-lasting anticholinergic drug, bilaterally reduced the incorporation of radioactivity in the corpus striatum but did not alter that observed in the cerebellum or the rate of metabolism of (18F)NMSP in plasma. Pretreatment with unlabelled NMSP, a potent dopaminergic antagonist, reduced the incorporation of (N-11C-methyl)benztropine in all brain regions, with the greatest effect being in the corpus striatum greater than cortex greater than thalamus greater than cerebellum, but did not alter the rate of metabolism of the labelled benztropine in the plasma. These reductions in the incorporation of either (18F)NMSP or (N-11C-methyl)benztropine exceeded the normal variation in tracer incorporation in repeated studies in the same animal. This study demonstrates that PET can be used as a tool for investigating interactions between neurochemically different yet functionally linked neurotransmitters systems in vivo and provides insight into the consequences of multiple pharmacologic administration.

  18. Measurement of acetylcholinesterase (AChE) activity in living brain by positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Central cholinergic neuronal system has been known to be related to learning and memory, and its deficit is found in the brain of Alzheimer's disease (AD) and other degenerative disorders. Postmortem studies have shown that acetylcholinesterase (AChE), one of biochemical markers of central cholinergic nerve system, is consistently reduced in the cerebral cortex of patients with Alzheimer's disease (AD). Non-invasive mapping and/or measuring AChE activity in the living brain by positron emission tomography (PET) would be a useful tool for assessment of cholinergic dysfunction in AD and other disorders, and provide a direct method for validation of therapeutic efficacy of drugs, AChE inhibitors. We have challenged to measure AChE activity using tracers of substrate type, radiolabelled acetylcholine analogs, which are lipophilic enough to go across blood brain barrier and are metabolically trapped by AChE in the brain. The analogs designed, N-methylpiperidyl esters, were evaluated in terms of their metabolic rate and specificity against AChE. Studies examining the response to AChE activity showed metabolic accumulation of some analogs responded well to changes in cortical AChE activity in an animal model of AD. The study was further applied to living human by PET using [11C]N-methylpiperidyl-4-acetate (MP4A), which was chosen on the basis of its reactivity and specificity suitable for the human cortical AChE. Regional cerebral metabolic rate of MP4A reflecting AChE activity was quantitatively determined using three compartment model analysis of dynamic PET data and the arterial input function obtained by TLC-radioluminography or plasma samples. The kinetic analyses showed that AChE activities estimated were well agree with those of postmortem examination in cerebral cortices and thalamus in healthy subjects, and that there was significant reduction of cortical AChE activity in patients with AD. The results suggest feasibility of the present method for assessing ACh

  19. Parameters of facilitated glucose transport across the blood-brain barrier in subjects studied with positron emission tomography

    International Nuclear Information System (INIS)

    This contribution was undertaken as part of the interdisciplinary training for the author in this Laboratory, with the aim of providing an application of current concepts of membrane transport to a practical problem. It was intended to present a specific, mechanistic view of the physiology of glucose uptake in the brain on the basis of in vivo determinations of 18F-deoxyglucose (FDG) distribution by positron emission tomography

  20. Brain glucose utilization in systemic lupus erythematosus with neuropsychiatric symptoms: a controlled positron emission tomography study

    International Nuclear Information System (INIS)

    In contrast to morphological imaging [such as magnetic resonance imaging (MRI) or computed tomography], functional imaging may be of advantage in the detection of brain abnormalities in cases of neuropsychiatric systemic lupus erythematosus (SLE). Therefore, we studied 13 patients (aged 40±14 years, 11 female, 2 male) with neuropsychiatric SLE who met four of the American Rheumatism Association criteria for the classification of SLE. Ten clinically and neurologically healthy volunteers served as controls (aged 40±12 years, 5 female, 5 male). Both groups were investigated using fluorine-18-labelled fluorodeoxyglucose brain positron emission tomography (PET) and cranial MRI. The normal controls and 11 of the 13 patients showed normal MRI scans. However, PET scan was abnormal in all 13 SLE patients. Significant group-to-group differences in the glucose metabolic index (GMI=region of interest uptake/global uptake at the level of the basal ganglia and thalamus) were found in the parieto-occipital region on both sides: the GMI of the parieto-occipital region on the right side was 0.922±0.045 in patients and 1.066±0.081 in controls (P<0.0001, Mann Whitney U test), while on the left side it was 0.892±0.060 in patients and 1.034±0.051 in controls (P=0.0002). Parieto-occipital hypometabolism is a conspicuous finding in mainly MRI-negative neuropsychiatric SLE. As the parieto-occipital region is located at the boundary of blood supply of all three major arteries, it could be the most vulnerable zone of the cerebrum and may be affected at an early stage of the cerebrovascular disease. (orig.). With 1 fig., 1 tab

  1. Positron-emission tomography

    International Nuclear Information System (INIS)

    Positron-emission tomography (PET) combines early biochemical assessment of pathology achieved by nuclear medicine with the precise localization achieved by computerized image reconstruction. In this technique a chemical compound with the desired biological activity is labeled with a radioactive isotope that decays by emitting a positron, or positive electron. With suitable interpretation PET images can provide a noninvasive, regional assessment of many biochemical processes that are essential to the functioning of the organ that is being visualized

  2. Physiology and physiopathology of central type Benzodiazepine receptors: Study in the monkey and in human brain using positron emission tomography

    International Nuclear Information System (INIS)

    A new non-invasive technique that allows to study in a living subject central type benzodiazepine receptors is developed. A combined approach is applied using a specific positron-emitting radiotracer for the in vivo labelling of the receptors and positron emission tomography allowing, by external detection, a quantitative determination of tissue radioactivity. The radioligand used for the in vivo labelling of benzodiazepine receptors is the antagonist RO 15-1788 labelled with carbon 11. The various stages of the study are described: in vivo characterization in the monkey of central type benzodiazepine receptors; characterization of central type benzodiazepine receptors in human brain using selective molecules for the BZ1 benzodiazepine subclass; demonstration of the heterogeneity of central type benzodiazepine receptors in the brain; study of pathological alteration of benzodiazepine receptors in experimental epilepsy

  3. Elevated Brain Cannabinoid CB1 Receptor Availability in Posttraumatic Stress Disorder: A Positron Emission Tomography Study

    OpenAIRE

    Neumeister, Alexander; Normandin, Marc D.; Pietrzak, Robert H.; Piomelli, Daniele; Zheng, Ming-Qiang; Gujarro-Anton, Ana; Potenza, Marc N.; Bailey, Christopher R.; Lin, Shu-fei; Najafzadeh, Soheila; Ropchan, Jim; Henry, Shannan; Corsi-Travali, Stefani; Carson, Richard E; Huang, Yiyun

    2013-01-01

    Endocannabinoids and their attending cannabinoid type 1 receptor (CB1) have been implicated in animal models of posttraumatic stress disorder (PTSD). However, their specific role has not been studied in people with PTSD. Herein, we present an in vivo imaging study using positron emission tomography (PET) and the CB1-selective radioligand [11C]OMAR in individuals with PTSD, and healthy controls with lifetime histories of trauma (trauma controls [TC]) and those without such histories (healthy c...

  4. Positron emission tomography (PET) study of the alterations in brain pharmacokinetics of methamphetamine in methamphetamine sensitized animals

    International Nuclear Information System (INIS)

    I investigated the differences in brain pharmacokinetics of [11C]methamphetamine ([11C]MAP) in normal and MAP sensitized animals using positron emission tomography (PET). [11C]MAP was synthesized by an automated on-line [11C]methylation system. I newly produced MAP sensitized dog and monkey by repeated MAP treatment. The maximal level of accumulation of [11C]MAP in the sensitized dog brain was 1.4 times higher than that in the control. This result suggests the changes in the pharmacokinetic profile of MAP in the brain affect the development or expression of MAP-induced behavioral sensitization. However, the overaccumulation of [11C]MAP in the sensitized monkey brain was not observed due to the influence of anesthesia. (author)

  5. Study of brain uptake of etorphine, in vivo in the Baboon Papio-Papio, by positron emission tomography

    International Nuclear Information System (INIS)

    In order to study in vivo opiate receptors in brain, etorphine, a morphine-like drug was labelled with 11C. Etorphine possesses an extremely high affinity for specific opiate binding sites. It passes easily through the blood-brain barrier. The brain pharmacokinetics of 11C-etorphine was studied in vivo in the Baboon Papio-Papio, by positron emission tomography. 11C-etorphine concentration reached its maximum two minutes after intravenous injection and then decreased rapidly. In some experiments, cyprenorphine, a morphine antagonist, was injected subsequently in order to study the displacement of the radioactive ligand from brain structures. Hepato-biliary and blood pharmacokinetics of 11C-etorphine were also studied

  6. Instrumentation in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a three-dimensional medical imaging technique that noninvasively measures the concentration of radiopharmaceuticals in the body that are labeled with positron emitters. With the proper compounds, PET can be used to measure metabolism, blood flow, or other physiological values in vivo. The technique is based on the physics of positron annihilation and detection and the mathematical formulations developed for x-ray computed tomography. Modern PET systems can provide three-dimensional images of the brain, the heart, and other internal organs with resolutions on the order of 4 to 6 mm. With the selectivity provided by a choice of injected compounds, PET has the power to provide unique diagnostic information that is not available with any other imaging modality. This is the first five reports on the nature and uses of PET that have been prepared for the American Medical Association's Council on Scientific Affairs by an authoritative panel

  7. Positron emission tomography

    International Nuclear Information System (INIS)

    The aim of this project is to provide a simple summary of new trends in positron emission tomography and its basic physical principles. It provides thereby compendious introduction of the trends of the present development in diagnostics using PET systems. A review of available literature was performed. (author)

  8. Positron emission tomography

    CERN Document Server

    Paans, A M J

    2006-01-01

    Positron Emission Tomography (PET) is a method for measuring biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides such as 11C, 13N, 15O and 18F and by measuring the annihilation radiation using a coincidence technique. This includes also the measurement of the pharmacokinetics of labelled drugs and the measurement of the effects of drugs on metabolism. Also deviations of normal metabolism can be measured and insight into biological processes responsible for diseases can be obtained. At present the combined PET/CT scanner is the most frequently used scanner for whole-body scanning in the field of oncology.

  9. Tomography by positrons emission

    International Nuclear Information System (INIS)

    The tomography by positrons emission is a technology that allows to measure the concentration of positrons emission in a tri dimensional body through external measurements. Among the isotope emissions have carbon isotopes are (11C), of the oxygen (15O), of the nitrogen (13N) that are three the element that constitute the base of the organic chemistry. Theses have on of the PET's most important advantages, since many biological interesting organic molecules can be tracer with these isotopes for the metabolism studies 'in vivo' through PET, without using organic tracers that modify the metabolism. The mentioned isotopes, also possess the characteristic of having short lifetime, that constitute on of PET's advantages from the dosimetric point of view. Among 11C, 15O, and 13N, other isotopes that can be obtained of a generator as the 68Ga and 82Rb

  10. Positron emission tomography (PET) study of the alterations in brain distribution of [11C]dethamphetamine in methamphetamine sensitized dog

    International Nuclear Information System (INIS)

    [11C]Methamphetamine ([11C]MAP) was synthesized by an automated on-line [11C]methylation system for positron emission tomography (PET) study. We newly produced a MAP sensitized dog by repeated MAP treatment and studied the brain distribution of [11C]MAP in the normal and the MAP sensitized dog. The maximal level of accumulation of [11C]MAP in the sensitized dog brain was 1.4 times higher than that in the control. No difference was found in the metabolism of MAP between the two conditions. The significant increase of [11C]MAP in the MAP sensitized brain indicates that subchronic MAP administration causes some functional change in uptake site of MAP

  11. Magnetic resonance imaging-guided attenuation and scatter corrections in three-dimensional brain positron emission tomography

    CERN Document Server

    Zaidi, H; Slosman, D O

    2003-01-01

    Reliable attenuation correction represents an essential component of the long chain of modules required for the reconstruction of artifact-free, quantitative brain positron emission tomography (PET) images. In this work we demonstrate the proof of principle of segmented magnetic resonance imaging (MRI)-guided attenuation and scatter corrections in 3D brain PET. We have developed a method for attenuation correction based on registered T1-weighted MRI, eliminating the need of an additional transmission (TX) scan. The MR images were realigned to preliminary reconstructions of PET data using an automatic algorithm and then segmented by means of a fuzzy clustering technique which identifies tissues of significantly different density and composition. The voxels belonging to different regions were classified into air, skull, brain tissue and nasal sinuses. These voxels were then assigned theoretical tissue-dependent attenuation coefficients as reported in the ICRU 44 report followed by Gaussian smoothing and additio...

  12. Effects of trihexyphenidyl and L-dopa on brain muscarinic cholinergic receptor binding measured by positron emission tomography

    International Nuclear Information System (INIS)

    The effects of pharmacological intervention on brain muscarinic cholinergic receptor (mAChR) binding were assessed in seven patients with Parkinson's disease by positron emission tomography and carbon-11 labelled N-methyl-4-piperidyl benzilate ([11C]NMPB). [11C]NMPB was injected twice, approximately 2 hours apart, in each patient, to assess the effect of single doses of 4 mg of trihexyphenidyl (n=5) or 400 mg of L-dopa with 57 mg of benserazide (n=2) on the binding parameter of mAChRs (K3). There was a mean 28% inhibition of K3 values in the brain in the presence of trihexyphenidyl, which was assumed to reflect mAChR occupancy. No significant change in K3 was observed in the presence of L-dopa. This study demonstrates the feasibility of measuring mAChR occupancy by an anticholinergic medication with PET

  13. Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    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

  14. Positron emission tomography and migraine

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a brain imaging technique that allows in vivo studies of numerous physiological parameters. There have been few PET studies in migraine patients. Cerebral blood flow changes with no variations in brain oxygen consumption have been reported in patients with prolonged neurologic manifestations during migraine attacks. Parenteral administration of reserpine during migraine headache has been followed by a fall in the overall cerebral uptake of glucose. The small sample sizes and a number of methodologic problems complicate the interpretation of these results. Recent technical advances and the development of new PET tracers can be expected to provide further insight into the pathophysiology of migraine. Today cerebral cortex 5 HT2 serotonin receptors can be studied in migraine patients with PET

  15. Positron emission tomographic measurement of blood-to-brain and blood-to-tumor transport of 82Rb: the effect of dexamethasone and whole-brain radiation therapy

    International Nuclear Information System (INIS)

    Unidirectional blood-to-brain and blood-to-tumor transport rate constants for rubidium 82 were determined using dynamic positron emission tomography in patients with primary or metastatic brain tumors. Regional influx rate constants (K1) and plasma water volume (Vp) were estimated from the time course of blood and brain radioactivity following a bolus injection of tracer. Eight patients were studied before and 24 to 72 hours after treatment using pharmacological doses of dexamethasone, and 6 additional patients with metastatic brain tumors were studied before and within 60 to 90 minutes after 200- to 600-rad whole-brain radiation therapy. Steroid treatment was associated with a 9 to 48% decrease in tumor K1 and a 21% mean decrease in tumor Vp. No consistent changes in K1 or Vp were observed in control brain regions. Tumor K1 and Vp did not increase in patients undergoing whole-brain radiation therapy, all of whom were taking dexamethasone at the time of study. These data suggest that corticosteroids decrease the permeability of tumor capillaries to small hydrophilic molecules (including those of some chemotherapeutic agents) and that steroid pretreatment prevents acute, and potentially dangerous, increases in tumor capillary permeability following cranial irradiation

  16. The role of positron emission tomography in differentiating tumor recurrence from radiation necrosis in brain glioma patients

    International Nuclear Information System (INIS)

    Objective: To evaluate the role of 11C-methionine positron emission tomography (MET PET-CT) in differentiating tumor recurrence from radiation necrosis in brain glioma patients. Methods: From June 2008 to September 2009, 30 brain glioma patients with suspected tumor recurrence or radiation necrosis after radiotherapy were evaluated by MET PET-CT. The median time between initial radiotherapy and PET examination was 13.5 months. Tumor recurrence were confirmed by histological analysis while necrosis was based on histological analysis or the subsequent clinical follow-up. Results: Eighteen out of 19 patients were histologically confirmed tumor recurrence among those tumor recurrence shown by MET PET-CT after surgery or stereotactic biopsy. 11 patients were considered to have radiation necrosis because of stable neurological symptoms and without massive enlargement of the lesion during the after follow-up. The sensitivity, specificity and accuracy of MET PET-CT for detecting tumor recurrence were 100%, 91.7% and 96.7% respectively. Conclusion: MET PET-CT is a powerful tool in differentiating brain tumor recurrence from radiation necrosis after radiotherapy. (authors)

  17. Fundamental study of inter-scanner difference for a multi-center study in brain positron emission tomography

    International Nuclear Information System (INIS)

    We showed scanner dependence of brain 18F-FDG and 11C-PiB images by using phantom examination with nine kinds of positron emission tomography (PET) scanners. We used two types of phantoms, cylindrical phantom with 15 cm inside diameter and three-dimensional (3D) brain phantom, and we set the body phantom on the bed to examine the effect of scatter and random coefficients from outside of the axial field of view (AFOV). Radioactivity and distance of the two phantoms were determined by a pilot study to obtain a condition similar to the clinical study. Axial uniformity was evaluated by circular region of interest (ROI) of 12 cm diameter, set in the center of the reconstruction image of the cylindrical phantom. As a result, the standardized uptake value (SUV) was lower than the true value in some scanners, and there was a scanner in which the axial uniformity was deteriorated by high radioactivity outside the AFOV. In the cylindrical phantom, the axial uniformity of the scanner was improved using the new dead-time correction method; however, it was not improved in the 3D brain phantom. Quality-controlled PET scanners are important to maintain constant levels for multicenter studies. (author)

  18. Imaging cAMP-specific phosphodiesterase-4 in human brain with R-[11C]rolipram and positron emission tomography

    International Nuclear Information System (INIS)

    Evidence of disruptions in cAMP-mediated signaling in several neuropsychiatric disorders has led to the development of R-[11C]rolipram for imaging phosphodiesterase-4 (PDE4) enzymes with positron emission tomography (PET). The high-affinity PDE4 inhibitor rolipram was previously reported to have an antidepressant effect in humans. PDE4 is abundant in the brain, and it hydrolyzes cAMP produced following stimulation of various neurotransmitter systems. PDE4 is regulated by intracellular cAMP levels. This paper presents the first PET study of R-[11C]rolipram in living human brain. Consistent with the wide distribution of PDE4, high radioactivity retention was observed in all regions representing the gray matter. Rapid metabolism was observed, and kinetic analysis demonstrated that the data fit in a two-tissue compartment model. R-[11C]Rolipram is thus suitable for imaging PDE4 and possibly cAMP signal transduction in the living human brain with PET. (orig.)

  19. Positron emission mammography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Moses, William W.

    2003-10-02

    This paper examines current trends in Positron Emission Mammography (PEM) instrumentation and the performance tradeoffs inherent in them. The most common geometry is a pair of parallel planes of detector modules. They subtend a larger solid angle around the breast than conventional PET cameras, and so have both higher efficiency and lower cost. Extensions to this geometry include encircling the breast, measuring the depth of interaction (DOI), and dual-modality imaging (PEM and x-ray mammography, as well as PEM and x-ray guided biopsy). The ultimate utility of PEM may not be decided by instrument performance, but by biological and medical factors, such as the patient to patient variation in radiotracer uptake or the as yet undetermined role of PEM in breast cancer diagnosis and treatment.

  20. Positron emission tomography. Basic principles

    International Nuclear Information System (INIS)

    The basic principles of positron emission tomography (PET) technique are reviewed. lt allows to obtain functional images from gamma rays produced by annihilation of a positron, a positive beta particle. This paper analyzes positron emitters production in a cyclotron, its general mechanisms, and the various detection systems. The most important clinical applications are also mentioned, related to oncological uses of fluor-l8-deoxyglucose

  1. Carbon-11 and fluorine-18 chemistry devoted to molecular probes for imaging the brain with positron emission tomography

    International Nuclear Information System (INIS)

    Exploration of the living human brain in real-time and in a noninvasive way was for centuries only a dream, made, however, possible today with the remarkable development during the four last decades of powerful molecular imaging techniques, and especially positron emission tomography (PET). Molecular PET imaging relies, from a chemical point of view, on the use and preparation of a positron-emitting radiolabelled probe or radiotracer, notably compounds incorporating one of two short-lived radionuclides fluorine-18 (T1/2: 109.8 min) and carbon-11 (T1/2: 20.38 min). The growing availability and interest for the radio-halogen fluorine-18 in radiopharmaceutical chemistry undoubtedly results from its convenient half-life and the successful use in clinical oncology of 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG). The special interest of carbon-11 is not only that carbon is present in virtually all biomolecules and drugs allowing therefore for isotopic labelling of their chemical structures but also that a given molecule could be radiolabelled at different functions or sites, permitting to explore (or to take advantage of) in vivo metabolic pathways. PET chemistry includes production of these short-lived radioactive isotopes via nuclear transmutation reactions using a cyclotron, and is directed towards the development of rapid synthetic methods, at the trace level, for the introduction of these nuclides into a molecule, as well as the use of fast purification, analysis and formulation techniques. PET chemistry is the driving force in molecular PET imaging, and this special issue of the Journal of Labelled Compounds and Radiopharmaceuticals, which is strongly chemistry and radiochemistry-oriented, aims at illustrating, be it in part only, the state-of-the-art arsenal of reactions currently available and its potential for the research and development of specific molecular probes labelled with the positron emitters carbon-11 and fluorine-18,with optimal imaging properties for

  2. Substituted benzamides as ligands for visualization of dopamine receptor binding in the human brain by positron emission tomography

    International Nuclear Information System (INIS)

    Two substituted benzamides, FLB 524 and raclopride, were labeled with 11C and examined for their possible use as ligands for positron emission tomography (PET) scan studies on dopamine-2 (D-2) receptors in the brains of monkeys and healthy human subjects. Both ligands allowed the in vivo visualization of D-2 receptor binding in the corpus striatum caudate nucleus/putamen complex in PET-scan images. [11C]Raclopride showed a high ratio of specific striatal to nonspecific cerebellar binding, and the kinetics of binding of this ligand made it optimal for PET studies. The in vivo binding of [11C]raclopride in the striatum of cynomolgus monkeys was markedly reduced by displacement with haloperidol. In healthy human subjects, [11C]raclopride binding in the caudate nucleus/putamen was 4- to 5-fold greater than nonspecific binding in the cerebellum. In comparison with previously available ligands for PET-scan studies on central dopamine receptors in man, [11C]raclopride appears to be advantageous with regard to (i) specificity of binding to D-2 receptors, (ii) the high ratio between binding in dopamine-rich (caudate, putamen) and dopamine-poor (cerebellum) human brain regions, and (iii) rapid association and reversibility of specific binding

  3. Species differences in blood-brain barrier transport of three positron emission tomography radioligands with emphasis on P-glycoprotein transport

    DEFF Research Database (Denmark)

    Syvanen, S.; Lindhe, O.; Palner, M.;

    2009-01-01

    Species differences occur in the brain concentrations of drugs, but the reasons for these differences are not yet apparent. This study was designed to compare brain uptake of three radiolabeled P-glycoprotein (P-gp) substrates across species using positron emission tomography. Brain concentrations....... The fraction of the unbound radioligand in plasma was studied along with its metabolism. The effect of P-gp inhibition was investigated by administering cyclosporin A (CsA). Pronounced species differences were found in the brain and brain-to-plasma concentrations of [(11)C]verapamil, [(11)C]GR205171......, and [(18)F]altanserin with higher brain distribution in humans, monkeys, and minipigs than in rats and guinea pigs. For example, the brain-to-plasma ratio of [(11)C]GR205171 was almost 9-fold higher in humans compared with rats. The species differences were still present after P-gp inhibition...

  4. Species differences in blood-brain barrier transport of three positron emission tomography radioligands with emphasis on P-glycoprotein transport

    DEFF Research Database (Denmark)

    Syvänen, Stina; Lindhe, Orjan; Palner, Mikael;

    2009-01-01

    Species differences occur in the brain concentrations of drugs, but the reasons for these differences are not yet apparent. This study was designed to compare brain uptake of three radiolabeled P-glycoprotein (P-gp) substrates across species using positron emission tomography. Brain concentrations...... fraction of the unbound radioligand in plasma was studied along with its metabolism. The effect of P-gp inhibition was investigated by administering cyclosporin A (CsA). Pronounced species differences were found in the brain and brain-to-plasma concentrations of [(11)C]verapamil, [(11)C]GR205171, and [(18......)F]altanserin with higher brain distribution in humans, monkeys, and minipigs than in rats and guinea pigs. For example, the brain-to-plasma ratio of [(11)C]GR205171 was almost 9-fold higher in humans compared with rats. The species differences were still present after P-gp inhibition, although the...

  5. Positron emission tomography imaging of (2R,3R)-5-[18F]fluoroethoxybenzovesamicol in rat and monkey brain: a radioligand for the vesicular acetylcholine transporter

    International Nuclear Information System (INIS)

    Introduction: The regional brain distribution of (2R,3R)-5-[18F]fluoroethoxy-benzovesamicol ((-)-[18F]FEOBV), a radioligand for the vesicular acetylcholine transporter (VAChT), was examined in vivo in mice, rats and rhesus monkeys. Methods: Regional brain distributions of (-)-[18F]FEOBV in mice were determined using ex vivo dissection. MicroPET imaging was used to determine the regional brain pharmacokinetics of the radioligand in rat and rhesus monkey brains. Results: In all three species, clear heterogeneous regional brain distributions were obtained, with the rank order of brain tissues (striatum>thalamus>cortex>cerebellum) consistent with the distribution of cholinergic nerve terminals containing the VAChT. Conclusions: (-)-[18F]FEOBV remains a viable candidate for further development as an in vivo imaging agent for positron emission tomography (PET) studies of the VAChT in the human brain.

  6. Brain metabolism in patients with vegetative state after post-resuscitated hypoxic-ischemic brain injury: statistical parametric mapping analysis of F-18 fluorodeoxyglucose positron emission tomography

    Institute of Scientific and Technical Information of China (English)

    Yong Wook Kim; Hyoung Seop Kim; Young-Sil An

    2013-01-01

    Background Hypoxic-ischemic brain injury (HIBI) after cardiopulmonary resuscitation is one of the most devastating neurological conditions that causing the impaired consciousness.However,there were few studies investigated the changes of brain metabolism in patients with vegetative state (VS) after post-resuscitated HIBI.This study aimed to analyze the change of overall brain metabolism and elucidated the brain area correlated with the level of consciousness (LOC) in patients with VS after post-resuscitated HIBI.Methods We consecutively enrolled 17 patients with VS after HIBI,who experienced cardiopulmonary resuscitation.Overall brain metabolism was measured by F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) and we compared regional brain metabolic patterns from t7 patients with those from 15 normal controls using voxel-by-voxel based statistical parametric mapping analysis.Additionally,we correlated the LOC measured by the JFK-coma recovery scale-revised of each patient with brain metabolism by covariance analysis.Results Compared with normal controls,the patients with VS after post-resuscitated HIBI revealed significantly decreased brain metabolism in bilateral precuneus,bilateral posterior cingulate gyrus,bilateral middle frontal gyri,bilateral superior parietal gyri,bilateral middle occipital gyri,bilateral precentral gyri (PFEw correctecd <0.0001),and increased brain metabolism in bilateral insula,bilateral cerebella,and the brainstem (PFEw correctecd <0.0001).In covariance analysis,the LOC was significantly correlated with brain metabolism in bilateral fusiform and superior temporal gyri (P uncorrected <0.005).Conclusions Our study demonstrated that the precuneus,the posterior cingulate area and the frontoparietal cortex,which is a component of neural correlate for consciousness,may be relevant structure for impaired consciousness in patient with VS after post-resuscitated HIBI.In post-resuscitated HIBI,measurement of brain

  7. Positron emission tomography of FDG in schizophrenia

    International Nuclear Information System (INIS)

    The use of the Donner dynamic positron emission tomograph to study fluorodeoxyglucose labelled 18F uptake in the brain of six patients with schizophrenia is reported. The glucose metabolic rate and the local cerebral metabolic rate were calculated. The dynamic brain uptake data and the blood input function were used to calculate rate constants by an iterative least squares fitting program for all regions of interest chosen in the brain. Although the number of patients was small, differences in k3 were statistically significant in several brain regions compared with normal controls

  8. Positron Emission Tomography and Magnetic Resonance Imaging of the Brain in Fabry Disease

    DEFF Research Database (Denmark)

    Korsholm, Kirsten; Feldt-Rasmussen, Ulla; Granqvist, Henrik;

    2015-01-01

    also inspected visually and severity of white matter lesions (WMLs) was graded using a visual rating scale. RESULTS: In 28 patients brain-FDG-PET was normal; in 23 of these 28 patients brain MRI was normal--of the remaining five patients in this group, four patients had WMLs and one patient never had...

  9. Positron emission tomography studies in eating disorders: multireceptor brain imaging, correlates with behavior and implications for pharmacotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Guido K. [Department of Child and Adolescent Psychiatry, Center for Eating Disorders Research, School of Medicine, University of California San Diego, San Diego, CA 92123 (United States); Kaye, Walter H. [Department of Psychiatry, Western Psychiatric Institute and Clinic, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

    2005-10-01

    Modern imaging techniques that visualize disease-specific organ neurotransmitter or protein receptor sites are increasingly able to define pathological processes on a molecular level. One of those imaging modalities, positron emission tomography (PET), for the assessment of brain neuroreceptor binding has revolutionized the in vivo assessment of biologic markers that may be related to human behavior. Such studies may help identify chemical targets that may be directly related to psychiatric pathology and, thus, opportunities for pharmacological intervention. In this review, we describe results from PET studies in eating disorders (EDs). Eating disorders are frequently debilitating illnesses that are quite homogeneous in their presentation. Those studies that identified particular serotonin and dopamine receptor alterations can distinguish recovered ED subjects from controls as well as ED subgroups. Furthermore, correlations of receptor binding with behavioral constructs, such as harm avoidance or novelty seeking, could be found. These recognized receptors may now help us to move away from rather nonspecific treatment approaches in psychiatric research and clinic to the possibility of more syndrome- and symptom-specific treatment approaches.

  10. Positron emission tomography studies in eating disorders: multireceptor brain imaging, correlates with behavior and implications for pharmacotherapy

    International Nuclear Information System (INIS)

    Modern imaging techniques that visualize disease-specific organ neurotransmitter or protein receptor sites are increasingly able to define pathological processes on a molecular level. One of those imaging modalities, positron emission tomography (PET), for the assessment of brain neuroreceptor binding has revolutionized the in vivo assessment of biologic markers that may be related to human behavior. Such studies may help identify chemical targets that may be directly related to psychiatric pathology and, thus, opportunities for pharmacological intervention. In this review, we describe results from PET studies in eating disorders (EDs). Eating disorders are frequently debilitating illnesses that are quite homogeneous in their presentation. Those studies that identified particular serotonin and dopamine receptor alterations can distinguish recovered ED subjects from controls as well as ED subgroups. Furthermore, correlations of receptor binding with behavioral constructs, such as harm avoidance or novelty seeking, could be found. These recognized receptors may now help us to move away from rather nonspecific treatment approaches in psychiatric research and clinic to the possibility of more syndrome- and symptom-specific treatment approaches

  11. A determination of the regional brain/blood partition coefficient of water using dynamic positron emission tomography

    International Nuclear Information System (INIS)

    In order to investigate the validity of the single compartment model in measuring CBF with the use of 15O-labeled water (H2 15O), dynamic positron emission tomography (PET) was performed following bolus injection of H2 15O. Careful attention was paid to accuracy in the measurement system (especially for the input function). In the region of the putamen, which includes the smallest mixture of gray and white matters in addition to the smallest contamination of cerebrospinal fluid (CSF) spaces, the partition coefficient obtained was 0.88 +/- 0.06 (ml/g). The discrepancy from the prediction estimated from the brain/blood water content ratio was only 7%. This finding suggests that there is no more complicated model than the usual single compartment one to describe the physiological behaviour of 15O water. On the other hand, in the other cortical regions, the discrepancy was larger (e.g., about 12% for the insular cortex and 26% for the frontal cortex) than in the region of the putamen, and a significant fit-interval dependence was observed in the calculated parameters. These observations suggest a significant effect of tissue heterogeneity and/or contamination with nonperfusable spaces in actual clinical PET data

  12. The relationship between boron neutron capture therapy (BNCT) and positron emission tomography (PET) for malignant brain tumors

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is a particle irradiation therapy that is theoretically available for selective radiation of tumor cells. Boronophenylalanine-positron emission tomography (18F-BPA-PET) was used in this study. Boron is used as a tracer compound for the neutron capture reaction and has been particularly useful for the recent noncraniotomy BNCT. In this report, we introduce this type of PET as a principal axis in BNCT and relationship with PET. We calculated the drug accumulation to the tumor before neutron irradiation to individualize the treatment. We decided the indication for BNCT on the basis of a PET study and are now expanding the indications to other systemic cancers, including head and neck, lung, and liver cancers. In addition, other irradiation modalities have developed a radiation plan on the basis of a PET study, and several studies attempted improving the results; however, the lesion is exposed to high radiation doses and appear as high accumulation on BPA-PET during BNCT. We determined the neutron exposure time from the dosage for normal tissue in the actual treatment, but the lesion/normal tissue ratio obtained from BPA-PET is for evaluating the tumor dose and following the treatment plan. We also found that a PET study was useful in the follow-up stage to aid in diagnosis of pathologic conditions such as increase in tumor volume, recurrence, or radiation necrosis and for patients who had already been treated for malignant brain tumor. (author)

  13. Uptake of amino acids in brain tumours using positron emission tomography as an indicator for assessing metabolic activity and malignancy

    International Nuclear Information System (INIS)

    Diagnosis and post-therapeutic follow-up of tumour patients necessitates morphological and particularly functional imaging methods. For the latter approach positron emission tomography has proven a valid tool for the measurement of perfusion, of energy consumption parameters such as oxygen extraction, glucose metabolism and amino acid uptake. However, neither perfusion nor energy consumption parameters have yielded unambiguous information on the clinical status of various tumours in respect of their malignancy and their growth status. It is shown in this paper that amino acid uptake seems to be a valid measure for the functional activity of tumour tissue for a broad range of neoplasms. The uptake of 11C-L-Methionine was measured in 33 patients having various brain tumours, and was compared with 6 patients who had an infarction, and with 8 patients suffering from arachnoidal cysts. The amino acid uptake correlated well with the histological grading of the tumours and the clinical status of the patient. The uptake was well differentiated against metabolically inactive lesions. Parallel investigations on the uptake mechanisms of amino acids in an animal model have shown that transport phenomena regulate the uptake rather than protein synthesis rates. However, protein synthesis may nevertheless exercise a control function on the transport process. (orig.)

  14. Synthesis and characterization of EADAM: a selective radioligand for mapping the brain serotonin transporters by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jarkas, Nachwa [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); McConathy, Jonathan [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Department of Psychiatry and Behavior Sciences, Emory University, Atlanta, GA 30322 (United States); Votaw, John R. [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Voll, Ronald J. [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Malveaux, Eugene [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Camp, Vernon M. [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Williams, Larry [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Goodman, Robin R. [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States); Kilts, Clinton D. [Department of Psychiatry and Behavior Sciences, Emory University, Atlanta, GA 30322 (United States); Goodman, Mark M. [Department of Radiology, Division of Radiological Sciences, Emory University, Atlanta, GA 30322 (United States) and Department of Psychiatry and Behavior Sciences, Emory University, Atlanta, GA 30322 (United States)]. E-mail: mgoodma@emory.edu

    2005-01-01

    [{sup 11}C]N,N-Dimethyl-2-(2'-amino-4'-ethylphenylthio)benzylamine ([{sup 11}C]EADAM) was synthesized in the development of a serotonin transporter (SERT) imaging ligand for positron emission tomography (PET). The methods of ligand synthesis, results of in vitro characterization, {sup 11}C labeling and in vivo micro-PET imaging studies of [{sup 11}C]EADAM in cynomolgus monkey brain are described. {sup 11}C was introduced into N,N-dimethyl-2-(2'-amino-4'-ethylphenylthio)benzylamine () by alkylation of N-methyl-2-(2'-amino-4'-ethylphenylthio)benzylamine () in 32% radiochemical yield (end of bombardment [EOB], decay-corrected from [{sup 11}C]methyl iodide). Competition binding assays in cells stably expressing the transfected human dopamine transporter (DAT), SERT and norepinephrine transporter (NET) labeled with [{sup 3}H]WIN 35428 or [{sup 125}I]RTI-55, [{sup 3}H]citalopram and [{sup 3}H]nisoxetine, respectively, indicated the following order of SERT affinity: ADAM>EADAM>>fluvoxamine. The affinity of EADAM for DAT and NET was 500- and >1000-fold lower, respectively, than for SERT. Micro-PET brain imaging studies in a cynomolgus monkey demonstrated high [{sup 11}C]EADAM uptake in the striatum, thalamus and brainstem. [{sup 11}C]EADAM uptake in these brain regions peaked in less than 60 min following administration of [{sup 11}C]EADAM. The tissue-to-cerebellum ratios of the striatum, thalamus and brainstem were 1.67, 1.71 and 1.63, respectively, at 120 min postinjection of [{sup 11}C]EADAM. Analysis of monkey arterial plasma samples using high-pressure liquid chromatography determined there was no detectable formation of lipophilic radiolabeled metabolites capable of entering the brain. In a displacement experiment with citalopram in a cynomolgus monkey, radioactivity in the striatum, thalamus and brainstem was displaced 20-60 min after administration of citalopram. In a blocking experiment with citalopram in a cynomolgus monkey

  15. Metabolic evaluation of brain tumors by positron emission tomography using F-18 labeled Fluoroethyltyrosine compared to F-18 FDG

    International Nuclear Information System (INIS)

    Objectives: 18F Fluoroethyltyrosine (FET) is one of the 18F labeled tyrosine derivatives. It can be transported into the tumor cells via aminoacid transporters, mainly L-systems. Moreover 18F labeled aminoacid derivatives were expected to be used more conveniently and in off-site PET center. In this study, we evaluated the feasibility of 18F FET and the metabolic characteristics of primary brain tumors in tumor-bearing animal and patients with brain tumors on positron emission tomography (PET) using 18F labeled FET and 18F FDG. Methods: 18F FET was injected in the 9L tumor bearing rats (n=20). Tumor bearing rats were scarified at 10 min, 30 min, 1 hr, 2hr, 3 hr after injection of 18F FET. According to the organs, tissue radioactivities were measured to evaluate the biodistribution. We performed 18F FDG and 18F FET brain PET scans in 10 patients with suspected primary brain tumors on brain MRI. In visual assessments, FDG uptakes were classified into 5-point grade: white matter (WM); grade 1, WM to ipsilateral gray matter (IGM); grade 2, IGM; grade 3, IGM to contralateral gray matter (CGM); grade 4, CGM or more; grade 5. maximum SUV (maxSUV) of lesions were calculated on both 18F FET and 18F FDG PET scans. We correlated the 18F FDG uptakes with 18F FET uptakes by Spearman rank correlation. Results: In the biodistribution of tumor bearing rats, uptakes of 18F FET were 3.9±0.5 %ID/g in pancreas and 1.3 ±0.5 %ID/g in tumors at 1 hour and increased according to the time. Uptakes of other organs were not significantly different. In the patients with suspected brain tumors, 8 of 10 patients were proven to be gliomas (WHO grade 3-4; 5, WHO grade 2; 3) and 2 patients had cerebral infarcts. 5 high grade gliomas showed hypermetabolism (2 in FDG uptake grade 4, 3 in FDG uptake grade 5) and 3 low grade gliomas showed iso- to hypometabolism (1 in FDG uptake grade 1, 2 in FDG uptake grade 3) on 18F FDG PET. maxSUV of high grade and low grade gliomas were 5.8±2.3 and 3.3±1

  16. Fundamentals of positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography is a modern radionuclide method of measuring physiological quantities or metabolic parameters in vivo. The methods is based on: (1) Radioactive labelling with positron emitters; (2) the coincidence technique for the measurement of the annihilation radiation following positron decay; (3) analysis of the data measured using biological models. The basic aspects and problems of the method are discussed. The main fields of future research are the synthesis of new labelled compounds and the development of mathematical models of the biological processes to be investigated. (orig.)

  17. [Fundamentals of positron emission tomography].

    Science.gov (United States)

    Ostertag, H

    1989-07-01

    Positron emission tomography is a modern radionuclide method of measuring physiological quantities or metabolic parameters in vivo. The method is based on: (1) radioactive labelling with positron emitters; (2) the coincidence technique for the measurement of the annihilation radiation following positron decay; (3) analysis of the data measured using biological models. The basic aspects and problems of the method are discussed. The main fields of future research are the synthesis of new labelled compounds and the development of mathematical models of the biological processes to be investigated. PMID:2667029

  18. Mapping of brain function with positron emission tomography for pathophysiological analysis of neurological disorders

    Energy Technology Data Exchange (ETDEWEB)

    Nariai, Tadashi [Tokyo Medical and Dental Univ. (Japan). Graduate School

    2001-02-01

    The role of PET is discussed mainly through author's clinical experience in patients with brain lesions from the view of mapping of brain function. Procedure for PET concept in clinical practice is summarized. PET using tracers like [{sup 15}O]water and [{sup 18}F]fluorodeoxyglucose for mapping of the function has been used in combination with MRI, MEG (magnetoencephalography), SPECT and other imaging means for morphological identification. Actual those images before and after surgery are presented in cases of epilepsy, moyamoya disease, stegnosis of cervical artery, arteriovenous malformation and oligodendroglioma. Images of [{sup 11}C]flumazenil in epilepsies are also presented to show the neurological dysfunctions. PET evaluation of neurological functions is concluded to become more important in parallel with the advancement of therapeutics. (K.H.)

  19. Mapping of brain function with positron emission tomography for pathophysiological analysis of neurological disorders

    International Nuclear Information System (INIS)

    The role of PET is discussed mainly through author's clinical experience in patients with brain lesions from the view of mapping of brain function. Procedure for PET concept in clinical practice is summarized. PET using tracers like [15O]water and [18F]fluorodeoxyglucose for mapping of the function has been used in combination with MRI, MEG (magnetoencephalography), SPECT and other imaging means for morphological identification. Actual those images before and after surgery are presented in cases of epilepsy, moyamoya disease, stegnosis of cervical artery, arteriovenous malformation and oligodendroglioma. Images of [11C]flumazenil in epilepsies are also presented to show the neurological dysfunctions. PET evaluation of neurological functions is concluded to become more important in parallel with the advancement of therapeutics. (K.H.)

  20. [18F]MK-9470, a positron emission tomography (PET) tracer for in vivo human PET brain imaging of the cannabinoid-1 receptor

    OpenAIRE

    Burns, H. Donald; Van Laere, Koen; Sanabria-Bohórquez, Sandra; Hamill, Terence G.; Bormans, Guy; Eng, Wai-si; Gibson, Ray; Ryan, Christine; Connolly, Brett; Patel, Shil; Krause, Stephen; Vanko, Amy; Van Hecken, Anne; DUPONT, Patrick; De Lepeleire, Inge

    2007-01-01

    [(18)F]MK-9470 is a selective, high-affinity, inverse agonist (human IC(50), 0.7 nM) for the cannabinoid CB1 receptor (CB1R) that has been developed for use in human brain imaging. Autoradiographic studies in rhesus monkey brain showed that [(18)F]MK-9470 binding is aligned with the reported distribution of CB1 receptors with high specific binding in the cerebral cortex, cerebellum, caudate/putamen, globus pallidus, substantia nigra, and hippocampus. Positron emission tomography (PET) imaging...

  1. Synthesis of radiotracers for studying muscarinic cholinergic receptors in the living human brain using positron emission tomography: [11C]dexetimide and [11C]levetimide

    International Nuclear Information System (INIS)

    The localization and quantitation of muscarinic cholinergic receptors (m-AChR) in the living human brain using a non-invasive method such as positron emission tomography (PET) may provide valuable information about receptor changes which have been observed post mortem in patients with Huntington's chorea and Alzheimer's dementia, as well as normal brain mechanisms mediated by the m-AChR. We chose to label dexetimide as a radiotracer for studying the m-AChR and levetimide as a radiotracer for assessing non-specific binding associated with the in vivo receptor binding studies. (author)

  2. Blood to brain iron uptake in one Rhesus monkey using [Fe-52]-citrate and positron emission tomography (PET): influence of haloperidol

    International Nuclear Information System (INIS)

    Iron is highly concentrated in the basal ganglia of the brain. The involvement of cerebral iron and its handling systems in neurodegenerative brain diseases like Parkinson's disease and tardive dyskinesia is currently under close investigation. There is evidence from animal studies that neuroleptics can increase iron uptake into brain. This effect appeared to be due to alteration of blood-brain barrier transport by the neuroleptics, particularly chlorpromazine and haloperidol, but not clozapine. We have investigated one Rhesus monkey using positron emission tomography (PET) and [Fe-52]-citrate before and during haloperidol administration. After drug withdrawal during a period of 1.5 year the investigation procedure was repeated. The results show that in the investigated monkey haloperidol induces a reversible marked increase of iron transport across the blood brain barrier concomitant with a large increase in elimination rate of the tracer from the blood. (author)

  3. Blood to brain iron uptake in one rhesus monkey using [Fe-52]-citrate and positron emission tomography (PET): influence of haloperidol.

    Science.gov (United States)

    Leenders, K L; Antonini, A; Schwarzbach, R; Smith-Jones, P; Reist, H; Ben-Shachar, D; Youdim, M; Henn, V

    1994-01-01

    Iron is highly concentrated in the basal ganglia of the brain. The involvement of cerebral iron and its handling systems in neurodegenerative brain diseases like Parkinson's disease and tardive dyskinesia is currently under close investigation. There is evidence from animal studies that neuroleptics can increase iron uptake into brain. This effect appeared to be due to alteration of blood-brain barrier transport by the neuroleptics, particularly chlorpromazine and haloperidol, but not clozapine. We have investigated one Rhesus monkey using positron emission tomography (PET) and [Fe-52]-citrate before and during haloperidol administration. After drug withdrawal during a period of 1.5 year the investigation procedure was repeated. The results show that in the investigated monkey haloperidol induces a reversible marked increase of iron transport across the blood brain barrier concomitant with a large increase in elimination rate of the tracer from the blood. PMID:7884394

  4. Use of PET Images in Assessment of Brain Absorbed Dose of Patients Undergoing [C-11] Raclopride Positron Emission Tomography

    International Nuclear Information System (INIS)

    The positron emission tomography (PET) in combination with [C-11] raclopride is commonly used for early detection of the Parkinson's disease. Injection of considerable amount of radioactivity, typically 300∼500 MBq of [C-11] at a time, for the examination calls for attention to doses to tissues of the patient, particularly to the brain. Since [C-11] raclopride is not a common radiopharmaceutical, dosimetric data for internal dose evaluation are rare yet. In this study, an attempt was made to determine doses to the brain and the striatum of patients by use of the PET images obtained for the clinical purposes. Four informed patients suffering Parkinson's disease participated in this study. Time series of 18 frames, 35 slices in each frame, of PET images of the head were obtained. By transforming the pixel intensity in the assigned region of interests into radioactivity contents, the retention curves were constructed to evaluate the residence times. Absorbed doses to the target tissues were calculated by applying the S-values given in the MIRDOSE3.1 code. The resulting dose coefficients for the whole brain and the striatum were 0.0110±0.0016 mGy/MBq and 0.0664±0.0238 mGy/MBq, respectively. The brain dose coefficient is considerably higher than the corresponding values in other studies employing healthy subjects. This may be attributed to probable enhanced capture of [C-11] raclopride by the dopamine D2 receptors in case of subjects with Parkinson's disease. The transcrianial magnetic stimulation (TMS) procedures are often used in treatment of Parkinson's disease. If the procedure stimulates secretion of dopamine, less retention of [C-11] raclopride is expected due to competition. So the similar assessments were made for the same patients after TMS treatments. Disappointingly, the ratios of residence time without TMS to that with TMS were 0.943±0.074 and 0.98±0.14 for the brain and the striatum, respectively. For the striatum, the ratios for three patients were

  5. Assessment of regional glucose metabolism in aging brain and dementia with positron-emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Reivich, M.; Alavi, A.; Ferris, S.; Christman, D.; Fowler, J.; MacGregor, R.; Farkas, T.; Greenberg, J.; Dann, R.; Wolf, A.

    1981-01-01

    This paper explores the alterations in regional glucose metabolism that occur in elderly subjects and those with senile dementia compared to normal young volunteers. Results showed a tendency for the frontal regions to have a lower metabolic rate in patients with dementia although this did not reach the level of significance when compared to the elderly control subjects. The changes in glucose metabolism were symmetrical in both the left and right hemispheres. There was a lack of correlation between the mean cortical metabolic rates for glucose and the global mental function in the patients with senile dementia. This is at variance with most of the regional cerebral blood flow data that has been collected. This may be partly related to the use of substrates other than glucose by the brain in elderly and demented subjects. (PSB)

  6. Functional brain mapping using H215O positron emission tomography (I): statistical parametric mapping method

    International Nuclear Information System (INIS)

    We investigated the statistical methods to compose the functional brain map of human working memory and the principal factors that have an effect on the methods for localization. Repeated PET scans with successive four tasks, which consist of one control and three different activation tasks, were performed on six right-handed normal volunteers for 2 minutes after bolus injections of 925 MBq H215O at the intervals of 30 minutes. Image data were analyzed using SPM96 (Statistical Parametric Mapping) implemented with Matlab (Mathworks Inc., U.S.A.). Images from the same subject were spatially registered and were normalized using linear and nonlinear transformation methods. Significant difference between control and each activation state was estimated at every voxel based on the general linear model. Differences of global counts were removed using analysis of covariance (ANCOVA) with global activity as covariate. Using the mean and variance for each condition which was adjusted using ANCOVA, t-statistics was performed on every voxel. To interpret the results more easily, t-values were transformed to the standard Gaussian distribution (Z-score). All the subjects carried out the activation and control tests successfully. Average rate of correct answers was 95%. The numbers of activated blobs were 4 for verbal memory I, 9 for verbal memory II, 9 for visual memory, and 6 for conjunctive activation of these three tasks. The verbal working memory activates predominantly left-sided structures, and the visual memory activates the right hemisphere. We conclude that rCBF PET imaging and statistical parametric mapping method were useful in the localization of the brain regions for verbal and visual working memory

  7. Cyclotron, positrons and PET [positron emission tomography]. An overview

    International Nuclear Information System (INIS)

    PET (positron emission tomography) is a powerful new scientific tool which is capable of revealing biochemical transformations while they are occurring in the brain and other organs in the living human body. The application of PET to problems in biology and medicine is dominated by the short half-life of the isotopes used to prepare the radiotracers. The most commonly used positron emitting isotopes are carbon-11, fluorine-18, nitrogen-13, and oxygen-15 which have half-lives of 20.4, 110, 10 and 2 minutes, respectively. Their incorporation into radiotracers having diverse chemical structures and biochemical specificities has allowed the study of blood flow, sugar metabolism, oxygen metabolism, neurotransmission, enzyme activity and binding sites for therapeutic drugs and substances of abuse. PET research is most commonly carried out at a Cyclotron-PET Center (cyclotron, positron emission tomography, chemistry laboratory) where the short-lived isotopes can be produced and used efficiently. The number of Cyclotron-PET Centers has grown from 4 in 1976 to several dozen in 1988 and the number is expected to double in the next five years attesting to the vitality of the field and the current and anticipated contributions to research in biology and medicine

  8. Experience on clinical application of positron emission tomography with a new radiopharmaceutical preparation Sodium 11C-butyrate in differential diagnosis of pathological volume brain formation

    International Nuclear Information System (INIS)

    Possibilities of the application of new radiopharmaceutical - sodium butyrate, [1-11C] (11C-Butyrate) for differential diagnosis of pathological volume brain formation were studied. Positron emission tomography (PET) of the brain was performed in 24 patients. In addition PET with 18F-FDG was performed in all patients. In 15 out of 24 patients the brain malignant tumor has been discovered, in 4 patients - benign tumors, in 5 - postoperative cysts. Results of the studies showed that the ratio tumor/normal tissue in case of 11C-Butyrate and 18F-FDG application proved to be comparable for all studied histological types of tumors. Malignant tumors in these cases had been visualized as a hot spots of increased uptake 11C-Butyrate (ratio ≥ 1). The obtained data testify to the diagnosis of the pathological volume brain formation

  9. Difference of cerebral hemodynamics and metabolism between traumatic focal brain injury and diffuse brain injury in recovery process. Positron emission tomographic evaluation

    International Nuclear Information System (INIS)

    We evaluated chronological changes of cerebral hemodynamics and metabolism of four focal brain injured (FBI) patients and four diffuse brain injured (DBI) patients in the chronic stage. We used positron emission tomography (PET) and compared the difference of the mechanism of recovery from neuronal damage between the two groups of subjects. The Glasgow Coma Scale score on admission was 6 to 14 in the FBI patients and 3 or 4 in the DBI patients. In the PET studies we examined regional cerebral blood flow (rCBF) and regional cerebral metabolic rate for oxygen (rCMRO2) in gray matter. We conclude from our observations that rCBF and rCMRO2 values were strikingly different between the lesion area and the remote area in FBI patients, but were very similar in every area of the cerebral gray matter in the group of DBI patients. PET showed a poor recovery pattern in the surrounding area of the contusion in FBI patients. However, it showed an improvement of the rCBF and rCMRO2 values in every area of the DBI patients whose clinical condition had improved. In areas remote from the contusion in FBI patients, the pattern of improvement of the PET values was very similar to that of DBI patients. This finding suggests that patients with FBI had some neuronal damage that was similar to that of DBI patients in remote areas from the contusion. The mechanism concerning the clinical improvement of the DBI patients is considered to involve axonal synaptic plasticity and the degree of clinical improvement to be strongly dependent on the degree of brain stem damage. (author)

  10. Repeated fluorodeoxyglucose positron emission tomography of the brain in infants with suspected hypoxic-ischaemic brain injury

    International Nuclear Information System (INIS)

    We performed repeated PET studies with fluorine-18 fluorodeoxyglucose (FDG) as a tracer to measure cerebral glucose metabolism for estimation of neurological prognosis in infants with suspected hypoxic-ischaemic brain injury. Fourteen infants (gestational age 35.3±4.67 weeks) were examined during the neonatal period (at age 38.4±2.7 weeks) and again at the age off 3.5±0.7 months; one further infant was studied only once at the age of 2.5 months. FDG accumulated most actively in the subcortical areas (thalami, brainstem and cerebellum) and the sensorimotor cortex during the neonatal period. The repeated PET study showed that the uptake of FDG was markedly high and increased in all brain sections of infants with normal development, whereas those with delayed development had significantly lower values. (orig.)

  11. Design, synthesis, radiolabeling and in vivo evaluation of potential positron emission tomography (PET) radioligands for brain imaging of the 5-HT7 receptor

    DEFF Research Database (Denmark)

    Lacivita, Enza; Niso, Mauro; Hansen, Hanne D.; Di Pilato, Pantaleo; Herth, Matthias Manfred; Lehel, Szabolcs; Ettrup, Anders; Montenegro, Lisa; Perrone, Roberto; Berardi, Francesco; Colabufo, Nicola A.; Leopoldo, Marcello; Knudsen, Gitte M.

    2014-01-01

    Here we describe the design, synthesis, and pharmacological evaluation of a set of compounds structurally related to the high affinity serotonin 5-HT7 receptor agonist N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide (6, LP-211). Specific structural modifications were performed in or....... Positron emission tomography (PET) analysis revealed that [(11)C]-23a and [(11)C]-26a were P-glycoprotein (P-gp) substrates and rapidly metabolized, resulting in poor brain uptake. These features were not predicted by in vitro tests....

  12. Positron emission tomography

    International Nuclear Information System (INIS)

    PET is a unique tool for the direct in vivo evaluation of physiologic processes within discrete areas of the brain. Thus far, its application to the study of schizophrenia has served to confirm the subtleties of this illness. However, PET does promise to increase our knowledge of the neurochemical anatomy of the normal and abnormal mind with respect to goal-directed behavior.22 references

  13. Human brain mapping under increasing cognitive complexity using regional cerebral blood flow measurements and positron emission tomography.

    Science.gov (United States)

    Law, Ian

    2007-11-01

    Measurement of the regional cerebral blood flow (rCBF) is an important parameter in the evaluation of cerebral function. With positron emission tomography (PET) rCBF has predominantly been quantified using the short-lived radiotracer oxygen-15 labelled water (H 2 15 O) and an adaptation of the Kety one-tissue compartment autoradiographic model. The values attained in putative grey matter, however, are systematically underestimated because of the limited scanner resolution. For this reason we applied a dynamic kinetic two-tissue compartment model including a fast and a slow flow component each with a perfusable tissue fraction. In the fast component rCBF was 2-2.5 times greater than grey matter values using traditional autoradiography in both human and monkey. Visual stimulation in human gave a corrected rCBF increase of approximately 40%. Visual stimulation was also used to indirectly validate carbon-10 labelled carbondioxide ( 10 CO 2 ), a new very short-lived rCBF PET tracer with a half-life of only 19.3 seconds. This allowed an increase in the number of independent PET scans per subject from 12-14 using H 2 15 O to 64 using 10 CO 2 . The experiment demonstrated a maximal activation response in the visual cortex at a 10-15 Hz stimulation frequency. The use of the rCBF PET mapping technique is illustrated by studies of the organization of language and the oculomotor system. With respect to the former, we found confirmation of neuropsychological evidence of the involvement of the left supramarginal/angular gyrus in reading in Japanese of a phonologically based script system, Kana, and of the left posterior inferior temporal gyrus in reading of a morphogram based script system, Kanji. Concerning the organization of the oculomotor system we found overlapping areas in fronto-parietal cortex involved in maintaining visual fixation, and performing visually guided and imagined eye movements. These data show that overt eye movements are not a prerequisite of the

  14. In vivo evaluation of [11C]preladenant positron emission tomography for quantification of adenosine A2A receptors in the rat brain

    NARCIS (Netherlands)

    Zhou, Xiaoyun; Khanapur, Shivashankar; de Jong, Johan R; Willemsen, Antoon T.M.; Dierckx, Rudi Ajo; Elsinga, Philip H; de Vries, Erik Fj

    2016-01-01

    [(11)C]Preladenant was developed as a novel adenosine A2A receptor positron emission tomography radioligand. The present study aims to evaluate the suitability of [(11)C]preladenant positron emission tomography for the quantification of striatal A2A receptor density and the assessment of striatal A2

  15. Positron emission tomography and basal ganglia functions

    International Nuclear Information System (INIS)

    With the advent of positron emission tomography (PET), studies on the human brain function and pathophysiology of brain damage have been extremely progressed. It is well-known that the basal ganglia plays an important role as one of the central nervous system involved in exercise regulation. More recently, the potential involvement of the basal ganglia in psychological processes, such as cognitive function, has been pointed out, receiving much attention. In spite of such a lot of studies, however, basal ganglia function remains unclear. This paper describes the relationships between PET findings and basal ganglia function. PET findings are discussed in relation to brain energy metabolism and striatal dopamine function. Pathophysiology of the basal ganglia are described in terms of the following diseases: Parkinson's disease, Parkinson's syndrome, progressive supranuclear palsy, Huntington's disease, and dystonia. Physiological backgrounds of the basal ganglia for PET images are also referred to. (N.K.) 75 refs

  16. Glucose transport and utilization in the human brain: model using carbon-11 methylglucose and positron emission tomography

    International Nuclear Information System (INIS)

    3-0-[11C]-Methyl-D-glucose (CMG) is specifically suited for measuring carrier facilitated glucose (G) transport; it enters the free G pool in tissue from where it is not utilized for metabolism in contrast to G, but is transported back into circulation. The ratio of carrier affinity for G and CMG was reported to be 1.11. By simultaneously measuring CMG concentration in plasma and in cerebral cortex in vivo with positron tomography at 1-min intervals for 40 min, two time-activity curves are obtained, as reported previously, which together with the G concentration in plasma yield the in vivo rate constants of G transport across the blood-brain barrier and the rate of G inflow; a repeat measurement at a different G concentration in plasma gives the in vivo Michaelis-Menten constant KM and the maximal rate of transport VMAX. The present paper summarizes and extends this approach to analyzing the free G pool in tissue, the rate of G return to circulation, and the rate of G exit into metabolism with its corresponding rate constants. The data from six volunteers agreed with results reported for the individual biochemical parameters in primate brains

  17. Brain kinetics of 11 C-labelled L-tryptophan and 5-hydroxy-L-tryptophan in the Rhesus monkey. A study using positron emission tomography

    International Nuclear Information System (INIS)

    5-hydroxy-L-tryptophan labelled with 11 C is introduced as a tracer for the vivo assessment of brain serotonin synthesis in the Rhesus monkey using positron emission tomography, PET. Increasing radioactivities were seen in the striatal area in contrast to that seen in other brain regions. Following 11 C-labelled L-tryptophan an even spread of brain radioactivity was seen. This selective increase most probably results from the decarboxylation of tracer and retention of formed products since no striatal increase of radioactivity was seen when 5-hydroxy-L-tryptophan labelled with 11 C in the carboxy-position was administered. Furthermore, pretreatment of the monkey with a centrally active decarboxylase inhibitor (NSD 1015, 10 mg/kg) did not lead to increased striatal radioactivities after the administration of 5-hydroxy-(β-11 C)-L-tryptophan. The selective utilization of the radiotracer in the striatal area increased with a rate constant calculated to be 0.0055 ± 0.0015 min-1 (n=5) using the surrounding brain as reference area. A non-significant influence of radiolabelled metabolites to the rate constants measured was shown after pretreatment of the monkeys with selective and non-selective monoamine oxidase inhibitors, respectively. These results may give a basis for the use of the new tracer 5-hydroxy-(β-11 C)-L-tryptophan in PET-studies of brain serotonin metabolism in health and disease. (authors)

  18. Dopamine D1 receptor imaging in the rodent and primate brain using the isoquinoline (+)-[{sup 11}C]A-69024 and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Besret, L.; Herard, A.S.; Guillermier, M.; Hantraye, P. [CNRS, URA 2210, F-91406 Orsay (France); Dolle, F.; Demphel, S.; Hinnen, F.; Coulon, C.; Ottaviani, M.; Bottlaender, M. [CEA, DSV, I2BM, SHFJ, Lab Imagerie Mol Expt, F-91406 Orsay (France); Herard, A.S.; Guillermier, M.; Hantraye, P. [CEA, DSV, I2BM, Mol Imaging Res Ctr, F-92265 Fontenay Aux Roses (France); Kassiou, M. [Univ Sydney, Discipline Med Radiat Sci, Sydney, NSW 2006 (Australia); Kassiou, M. [Univ Sydney, Brain and Mind Res Inst, Sydney, NSW 2050 (Australia); Kassiou, M. [Univ Sydney, Sch Chem, Sydney, NSW 2006 (Australia)

    2008-07-01

    In vivo pharmacokinetic and brain binding characteristics of (+)-[{sup 11}C]A-69024, a high-affinity-D1-selective dopamine receptor antagonist, were assessed with micro-PET and {beta}-microprobes in the rat and PET in the baboon. The biodistribution of (+)-[{sup 11}C]A-69024 in rats and baboons showed a rapid brain uptake (reaching a maximal value at 5 and 15 min postinjection in rats and baboons, respectively), followed by a slow wash out. The region/cerebellum concentration ratio was characterized by a fourfold higher uptake in striatum and a twofold higher uptake in cortical regions, consistent with in vivo specific binding of the radiotracer in these cerebral regions. Furthermore, this specific (+)-[{sup 11}C]A-69024 binding significantly correlated with the reported in vitro distribution of dopamine D1-receptors. Finally, the specific uptake of the tracer in the striatum and cortical regions was completely prevented by either a pretreatment with large doses of nonradioactive {+-}A-69024 or of the D1-selective antagonist SCH23390, resulting in a similar uptake in the reference region (cerebellum) and in other brain regions. Thus, (+)-[{sup 11}C]A-69024 appears to be a specific and enantioselective radioligand to visualize and quantify brain dopamine D1 receptors in vivo using positron emission tomography. (authors)

  19. Brain glucose metabolic changes associated with chronic spontaneous Pain due to brachial plexus avulsion:a preliminary positron emission tomography study

    Institute of Scientific and Technical Information of China (English)

    CHEN Fu-yong; TAO Wei; CHENG Xin; WANG Hong-yan; HU Yong-sheng; ZHANG Xiao-hua; LI Yong-jie

    2008-01-01

    Background Previous brain imaging studies suggested that the brain activity underlying the perception of chronic pain maV differ from that underlying acute pain.To investigate the brain regions involved in chronic spontaneous pain due to brachial plexus avulsion(BPA),fluorine-18fluorodeoxygIucose (19F-FDG) positron emission tomography (PET) scanning was applied to determine the glucose metabolic changes in patients with pain due to BPA.Methods Six right-handed patients with chronic spontaneous pain due to left-BPA and twelve right-handed age-and sex-matched healthy control subjects participated in the 18F-FDG PET study.The patients were rated by visual analog scale (VAS) during scanning and Hamilton depression scale and Hamilton anxiety scale after scanning.Statistical parametric mapping 2 (SPM2) was applied for data analysis.Results Compared with healthy subjects,the patients had significant glucose metabolism decreases in the right thalamus and S I(P<0.001,uncorrected),and significant glucose metabolism increases in the right orbitofrontaI cortex (OFC) (BA11),left rostral insula cortex and left dorsolateral prefrontal codex (DLPFC) (BA10/46) (P<0.001,uncorrected).Conclusion These findings suggest that the brain areas involved in emotion.aRention and internal modulation of pain may be related to the chronic spontaneous pain due to BPA.

  20. Preparation and biodistribution in mice of ( sup 11 C)carfentanil; A radiopharmaceutical for studying brain. mu. -opioid receptors by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Saji, Hideo; Tsutsumi, Daisuke; Iida, Yasuhiko; Yokoyama, Akira (Kyoto Univ. (Japan). Faculty of Pharmaceutical Science); Magata, Yasuhiro; Konishi, Junji

    1992-02-01

    A potent {mu}-opioid agonist, ({sup 11}C)carfentanil, was prepared by the methylation of carfentanil carboxylic acid with ({sup 11}C)methyl iodide in order to study brain {mu}-opioid receptors by positron emission tomography. Synthesis (including purification) was completed within 25 min and the radiochemical yield was approximately 40%. The radiochemical purity of the product was more than 99% and its specific activity was 3.7-7.4 GBq/{mu}mol. Biodistribution studies performed in mice after intravenous injection showed a high brain uptake and rapid blood clearance, so a high brain/blood ratio of 1.5-1.8 was found from 5 to 30 min. Regional cerebral distribution studies in the mouse showed a significantly higher uptake of ({sup 11}C)carfentanil by the thalamus and striatum than by the cerebellum, with the radioactivity in the striatum disappearing more rapidly than that in the thalamus. Treatment with naloxone significantly reduced the uptake of ({sup 11}C)carfentanil by the thalamus and striatum. These results indicate that ({sup 11}C)carfentanil binds specifically to brain {mu}-opioid receptors. (author).

  1. Hemodynamic changes during neural deactivation in human brain. A positron emission tomography study of crossed cerebellar diaschisis

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Kanno, Iwao; Shimosegawa, Eku; Tamura, Hajime; Okane, Kumiko; Hatazawa, Jun [Research Inst. for Brain and Blood Vessels, Akita (Japan)

    2002-06-01

    The mechanism of crossed cerebellar diaschisis (CCD) is considered to be secondary hypoperfusion due to neural deactivation. To elucidate the hemodynamics during neural deactivation, the hemodynamics of CCD was investigated. The cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF), cerebral metabolic rate of oxygen (CMRO{sub 2}), and vascular responses to hypercapnia and acetazolamide stress for CCD were measured in 20 patients with cerebrovascular disease by positron emission tomography with H{sub 2}{sup 15}O, C{sup 15}O, and {sup 15}O{sub 2}. Vascular responses to hypercapnia and acetazolamide stress were almost the same between CCD side and unaffected side of the cerebellum, a finding that supports the idea that the mechanism of CCD is secondary hypoperfusion due to neural deactivation. The degree of decrease in CBF on the CCD side was almost the same as that in CBV, indicating that vascular blood velocity does not change during neural deactivation. The relation between CBF and CBV of the CCD and unaffected sides was CBV=0.29 CBF{sup 0.56}. On the CCD side, the degree of decrease in CMRO{sub 2} was less than that in CBF, resulting in a significantly increased OEF. The increased OEF along with the decreased CBV on the CCD side might indicate that neural deactivation primarily causes vasoconstriction rather than a reduction of oxygen metabolism. (author)

  2. Sex-related differences in the muscarinic acetylcholinergic receptor in the healthy human brain. A positron emission tomography study

    International Nuclear Information System (INIS)

    We evaluated the sex-related differences in the decline of the cerebral muscarinic acetylcholinergic receptor (mACh-R) due to aging by using 11C-N-methyl-4-piperidyl benzilate (11C-NMPB) and positron emission tomography (PET). The subjects consisted of 37 (20 males and 17 females) healthy volunteers. The 11C-NMPB uptake was evaluated by the ratio method (regional 11C-NMPB uptake/Cerebellar 11C-NMPB uptake; rNMPB ratio). The correlation between sex, aging, and the rNMPB ratio in normal aging was evaluated by a multiple regression analysis. The rNMPB ratio was higher in females than in males throughout the entire cerebral region (p<0.01-p<0.0001) and the rNMPB ratio might thus possibly decline with age more rapidly in females. Our study therefore revealed the existence of sex-related differences in the cerebral mACh-R. (author)

  3. Evaluation of the P-glycoprotein- and breast cancer resistance protein-mediated brain penetration of 11C-labeled topotecan using small-animal positron emission tomography

    International Nuclear Information System (INIS)

    Introduction: Topotecan (TPT) is a camptothecin derivative and is an anticancer drug working as a topoisomerase-I-specific inhibitor. But TPT cannot penetrate through the blood-brain barrier. In this study, we synthesized a new positron emission tomography (PET) probe, [11C]TPT, to evaluate the P-glycoprotein (Pgp)- and breast cancer resistance protein (BCRP)-mediated brain penetration of [11C]TPT using small-animal PET. Methods: [11C]TPT was synthesized by the reaction of a desmethyl precursor with [11C]CH3I. In vitro study using [11C]TPT was carried out in MES-SA and doxorubicin-resistant MES-SA/Dx5 cells in the presence or absence of elacridar, a specific inhibitor for Pgp and BCRP. The biodistribution of [11C]TPT was determined using small-animal PET and the dissection method in mice. Results: The transport of [11C]TPT to the extracellular side was determined in MES-SA/Dx5 cells exhibiting the expressions of Pgp and BCRP at high levels. This transport was inhibited by coincubation with elacridar. In Mdr1a/b-/-Bcrp1-/- mice, PET results indicated that the brain uptake of [11C]TPT was about two times higher than that in wild-type mice. Similarly, the brain penetration of [11C]TPT in wild-type mice was increased by treatment with elacridar. The radioactivity in the brain of elacridar-treated mice was maintained at a certain level after the injection of [11C]TPT, although the radioactivity in the blood decreased with time. Conclusions: We demonstrated the increase of brain penetration of [11C]TPT by deficiency and inhibition of Pgp and BCRP functions using small-animal PET in mice.

  4. Evaluation of the brain uptake properties of [1-11C] labeled hexanoate in anesthetized cats by means of positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) was performed on the cat brain to characterize [1-11C] hexanoate and other [1-11C] labeled short and medium-chain fatty acids as a tracer of fatty acid oxidative metabolism. After an intravenous injection the brain uptake of [1-11C] hexanoate reached a peak followed by rapid washout until 2 min (first phase). Subsequently the total brain uptake was again increased and reached to a peak 7-10 min after tracer injection (second phase). The blood radioactivity of unmetabolized [1-11C] hexanoate was rapidly decreased and almost eliminated within the first 2 min, whereas the blood radioactivity of [11C]CO2/HCO3- was gradually increased and reached a peak approximately 5 min after tracer injection. As the effect of circulating [11C]CO2/HCO3- was examined by a bolus intravenous injection of [11C]CO2/HCO3-, the brain uptake of [11C]CO2/HCO3- was rapidly increased right after the injection and changed parallel to the blood level of [11C]CO2/HCO3-. These results suggest that, in contrast to the previous mouse data, the time-activity curve in the cat brain following intravenous injection of [1-11C] hexanoate has a biphasic pattern, the second phase being determined by peripherally originating [11C]CO2/HCO3-, and therefore does not reflect the metabolism of 11C-labeled fatty acid in the brain. (author)

  5. Positron emission tomography wrist detector

    Science.gov (United States)

    Schlyer, David J.; O'Connor, Paul; Woody, Craig; Junnarkar, Sachin Shrirang; Radeka, Veljko; Vaska, Paul; Pratte, Jean-Francois

    2006-08-15

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal representing a time-of-occurrence of an annihilation event, generating an address signal representing a channel detecting the annihilation event, and generating a channel signal including the time and address signals. The method also includes generating a composite signal including the channel signal and another similarly generated channel signal concerning another annihilation event. An apparatus that serially transfers annihilation information includes a time signal generator, address signal generator, channel signal generator, and composite signal generator. The time signal is asynchronous and the address signal is synchronous to a clock signal. A PET scanner includes a scintillation array, detection array, front-end array, and a serial encoder. The serial encoders include the time signal generator, address signal generator, channel signal generator, and composite signal generator.

  6. Positron emission tomography basic sciences

    CERN Document Server

    Townsend, D W; Valk, P E; Maisey, M N

    2003-01-01

    Essential for students, science and medical graduates who want to understand the basic science of Positron Emission Tomography (PET), this book describes the physics, chemistry, technology and overview of the clinical uses behind the science of PET and the imaging techniques it uses. In recent years, PET has moved from high-end research imaging tool used by the highly specialized to an essential component of clinical evaluation in the clinic, especially in cancer management. Previously being the realm of scientists, this book explains PET instrumentation, radiochemistry, PET data acquisition and image formation, integration of structural and functional images, radiation dosimetry and protection, and applications in dedicated areas such as drug development, oncology, and gene expression imaging. The technologist, the science, engineering or chemistry graduate seeking further detailed information about PET, or the medical advanced trainee wishing to gain insight into the basic science of PET will find this book...

  7. Specific in vivo binding in the rat brain of [18F]RP 62203: A selective 5-HT2A receptor radioligand for positron emission tomography

    International Nuclear Information System (INIS)

    In vivo pharmacokinetic and brain binding characteristics of [18F]RP 62203, a selective high-affinity serotonergic 5-HT2A receptor antagonist, were assessed in the rat following intravenous injection of trace amount of the radioligand. The radioactive distribution profile observed in the brain 60 min after injection was characterized by greater than fourfold higher uptake in neocortex as compared to cerebellum (0.38 ± 0.07% injected dose/g, % ID/g and 0.08 ± 0.01 ID/g, respectively), consistent with in vivo specific binding to the 5-HT2A receptor. Furthermore, specific [18F]RP 62203 binding significantly correlated with the reported in vitro distribution of 5-HT2A receptors, but not with known concentration profiles of dopaminergic D2 or adrenergic α1 receptors. Finally, detectable specific binding was abolished by pretreatment with large doses of ritanserin, a selective 5-HT2A antagonist, which resulted in uniform uptakes across cortical, striatal and cerebellar tissues. Thus, [18F]RP 62203 appears to be a promising selective tool to visualize and quantify 5-HT2A brain receptors in vivo with positron emission tomography

  8. Imaging cAMP-specific phosphodiesterase-4 in human brain with R-[{sup 11}C]rolipram and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    DaSilva, Jean N. [PET Centre, Centre for Addiction and Mental Health, University of Toronto, 250 College Street, Toronto, Ontario (Canada); Department of Psychiatry, University of Toronto, Toronto (Canada); Department of Pharmacology, University of Toronto, Toronto (Canada); University of Ottawa Heart Institute, Cardiac PET Centre, 40 Ruskin St., Ottawa, Ontario (Canada); Lourenco, Celia M. [PET Centre, Centre for Addiction and Mental Health, University of Toronto, 250 College Street, Toronto, Ontario (Canada); Department of Pharmacology, University of Toronto, Toronto (Canada); Meyer, Jeffrey H.; Houle, Sylvain [PET Centre, Centre for Addiction and Mental Health, University of Toronto, 250 College Street, Toronto, Ontario (Canada); Department of Psychiatry, University of Toronto, Toronto (Canada); Hussey, Douglas [PET Centre, Centre for Addiction and Mental Health, University of Toronto, 250 College Street, Toronto, Ontario (Canada); Potter, William Z. [Lilly Research Laboratories, Lilly Corporate Center, Indianapolis (United States)

    2002-12-01

    Evidence of disruptions in cAMP-mediated signaling in several neuropsychiatric disorders has led to the development of R-[{sup 11}C]rolipram for imaging phosphodiesterase-4 (PDE4) enzymes with positron emission tomography (PET). The high-affinity PDE4 inhibitor rolipram was previously reported to have an antidepressant effect in humans. PDE4 is abundant in the brain, and it hydrolyzes cAMP produced following stimulation of various neurotransmitter systems. PDE4 is regulated by intracellular cAMP levels. This paper presents the first PET study of R-[{sup 11}C]rolipram in living human brain. Consistent with the wide distribution of PDE4, high radioactivity retention was observed in all regions representing the gray matter. Rapid metabolism was observed, and kinetic analysis demonstrated that the data fit in a two-tissue compartment model. R-[{sup 11}C]Rolipram is thus suitable for imaging PDE4 and possibly cAMP signal transduction in the living human brain with PET. (orig.)

  9. The effects of donor stage on the survival and function of embryonic striatal grafts in the adult rat brain; II. Correlation between positron emission tomography and reaching behaviour

    International Nuclear Information System (INIS)

    proportion of striatal-like tissue within the grafts and an increase in functional D1 and D2 dopamine receptors measured by positron emission tomography, i.e. a more extensive integration of the graft with the host brain. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Synthesis, 18F-Radiolabelling and Biological Characterization of Novel Fluoroalkylated Triazine Derivatives for in Vivo Imaging of Phosphodiesterase 2A in Brain via Positron Emission Tomography

    Directory of Open Access Journals (Sweden)

    Susann Schröder

    2015-05-01

    Full Text Available Phosphodiesterase 2A (PDE2A is highly and specifically expressed in particular brain regions that are affected by neurological disorders and in certain tumors. Development of a specific PDE2A radioligand would enable molecular imaging of the PDE2A protein via positron emission tomography (PET. Herein we report on the syntheses of three novel fluoroalkylated triazine derivatives (TA2–4 and on the evaluation of their effect on the enzymatic activity of human PDE2A. The most potent PDE2A inhibitors were 18F-radiolabelled ([18F]TA3 and [18F]TA4 and investigated regarding their potential as PET radioligands for imaging of PDE2A in mouse brain. In vitro autoradiography on rat brain displayed region-specific distribution of [18F]TA3 and [18F]TA4, which is consistent with the expression pattern of PDE2A protein. Metabolism studies of both [18F]TA3 and [18F]TA4 in mice showed a significant accumulation of two major radiometabolites of each radioligand in brain as investigated by micellar radio-chromatography. Small-animal PET/MR studies in mice using [18F]TA3 revealed a constantly increasing uptake of activity in the non-target region cerebellum, which may be caused by the accumulation of brain penetrating radiometabolites. Hence, [18F]TA3 and [18F]TA4 are exclusively suitable for in vitro investigation of PDE2A. Nevertheless, further structural modification of these promising radioligands might result in metabolically stable derivatives.

  11. Regional distribution of the opioid receptor agonist N-(methyl- sup 11 C)pethidine in the brain of the rhesus monkey studied with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig, P. (Hospital Pharmacy, University Hospital, Uppsala (Sweden)); Eckernaes, S.Aa. (Departments of Neurology, University Hospital, Uppsala (Sweden)); Lindberg, B.S. (Department of Obstetrics and Gynaelogy, University Hospital, Uppsala (Sweden)); Lundqvist, H. (Centre for Radiation Sciences, University of Uppsala (Sweden)); Antoni, G.; Rimland, A.; Laangstroem, B. (Department of Organic Chemistry, University of Uppsala (Sweden))

    1990-01-01

    The regional distribution and kinetics in the brain of Rhesus monkeys of N-(methyl-{sup 11}C)-pethidine have been studied by positron emission tomography, PET. {sup 11}C-Pethidine reached the brain with peak radioactivities appearing within 6-10 min. after administration. Highest radioactivities were measured in areas corresponding to the thalamus, the striatal area and also the lowest transection of the temporal lobes, with an uptake of 2.7-3.1 times the homogenous dilution of the radioactive dose. Low radioactivities were seen in the cerebellum and the occipital lobes. This distribution corresponds to the regional density of opioid receptors using in vitro binding techniques. The {sup 11}C-pethidine derived radioactivity left the brain with an initial half-life of 40--60 minutes, followed by an elimination which paralleled the plasma elimination of unlabelled pethidine. After pretreatment of the monkey with a small dose of naloxone, the radioactivities decreased about 40% in areas corresponding to the thalamus, striatum and lowest section of the temporal lobes, indicating competition for the same binding sties. By the use of a three-compartment model, it was possible to get an estimate of {sup 11}C-pethidine receptor binding characteristics in the brain. The ratio of Kon/Koff, equal to Bmax.Kd, was 0.06-0.1. This indicates that pethidine is bound with low affinity to the opioid receptors and is a poor ligand for studies of opioid receptor function with PET. Brain kinetics of {sup 11}C-pethidine is mainly determined by its blood kinetics. (author).

  12. Regional distribution of the opioid receptor agonist N-(methyl-11C)pethidine in the brain of the rhesus monkey studied with positron emission tomography

    International Nuclear Information System (INIS)

    The regional distribution and kinetics in the brain of Rhesus monkeys of N-(methyl-11C)-pethidine have been studied by positron emission tomography, PET. 11C-Pethidine reached the brain with peak radioactivities appearing within 6-10 min. after administration. Highest radioactivities were measured in areas corresponding to the thalamus, the striatal area and also the lowest transection of the temporal lobes, with an uptake of 2.7-3.1 times the homogenous dilution of the radioactive dose. Low radioactivities were seen in the cerebellum and the occipital lobes. This distribution corresponds to the regional density of opioid receptors using in vitro binding techniques. The 11C-pethidine derived radioactivity left the brain with an initial half-life of 40-60 min., followed by an elimination which paralleled the plasma elimination of unlabelled pethidine. After pretreatment of the monkey with a small dose of naloxone, the radioactivities decreased about 40% in areas corresponding to the thalamus, striatum and lowest section of the temporal lobes, indicating competition for the same binding sties. By the use of a three-compartment model, it was possible to get an estimate of 11C-pethidine receptor binding characteristics in the brain. The ratio of Kon/Koff, equal to Bmax.(Kd, was 0.06-0.1. This indicates that pethidine is bound with low affinity to the opioid receptors and is a poor ligand for studies of opioid receptor function with PET. Brain kinetics of 11C-pethidine is mainly determined by its blood kinetics. (author)

  13. Scintillators for positron emission tomography

    International Nuclear Information System (INIS)

    Like most applications that utilize scintillators for gamma detection, Positron Emission Tomography (PET) desires materials with high light output, short decay time, and excellent stopping power that are also inexpensive, mechanically rugged, and chemically inert. Realizing that this ''ultimate'' scintillator may not exist, this paper evaluates the relative importance of these qualities and describes their impact on the imaging performance of PET. The most important PET scintillator quality is the ability to absorb 511 keV photons in a small volume, which affects the spatial resolution of the camera. The dominant factor is a short attenuation length (≤ 1.5 cm is required), although a high photoelectric fraction is also important (> 30% is desired). The next most important quality is a short decay time, which affects both the dead time and the coincidence timing resolution. Detection rates for single 511 keV photons can be extremely high, so decay times ≤ 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so ≤5 ns fwhm coincidence pair timing resolution is required to identify events with narrow coincidence windows, reducing contamination due to accidental coincidences. Current trends in PET cameras are toward septaless, ''fully-3D'' cameras, which have significantly higher count rates than conventional 2-D cameras and so place higher demands on scintillator decay time. Light output affects energy resolution, and thus the ability of the camera to identify and reject events where the initial 511 keV photon has undergone Compton scatter in the patient. The scatter to true event fraction is much higher in fully-3D cameras than in 2-D cameras, so future PET cameras would benefit from scintillators with a 511 keV energy resolution < 10--12% fwhm

  14. MR imaging and positron emission tomography of cortical heterotopia

    International Nuclear Information System (INIS)

    Heterotopia of the gray matter is a developmental malformation in which ectopic cortex is found in the white matter of the brain. A case of a 33-year-old man with cortical heterotopia who had a lifelong history of seizures and psychomotor retardation is reported, including the results of cerebral CT, magnetic resonance imaging, and positron emission tomography using 18F-2-deoxyglucose

  15. Abnormal brain glucose metabolism and depressive mood in patients with pre-dialytic chronic kidney disease: SPM analysis of F-18 FDG positron emission tomography

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the relationship between depressive mood and pre-dialytic CKD, to localize and quantify depressive mood -related lesions in pre-dialytic CKD patients through statistical parametric mapping (SPM) analysis of brain positron emission tomography (PET), and to examine the usefulness of brain PET for early detection and proper treatment of depressive mood. Twenty one patients with stage 5 CKD and 22 healthy volunteers were analyzed by depressive mood assessment and statistical parametric mapping (SPM) analysis of 18F-FDG PET. Depressive mood assessment was done by Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS). The largest clusters were areas including precentral gyrus, prefrontal cortex, and anterior cingulated cortex of left hemisphere. Other clusters were left transverse temporal gyrus, left superior temporal gyrus, right prefrontal cortex, right dorsolateral prefrontal cortex (BA 46, 44), right inferior frontal gyrus, right inferior parietal lobule, left angular gyrus. In addition, correlation was found between hypometabolized areas and HDRS scores of CKD patients in right prefrontal cortex (BA 11) and right anterior cingulated gyrus (BA 24). In conclusion, this study demonstrated specific depressive mood-related abnormal metabolic lesion. Interestingly, in CKD patients with severe depressive mood, cerebral metabolism was similar to that of MDD

  16. Positron emission tomographic studies on aromatic L-amino acid decarboxylase activity in vivo for L-dopa and 5-hydroxy-L-tryptophan in the monkey brain

    International Nuclear Information System (INIS)

    The regional brain kinetics following 5-hydroxy-L-(β-11 C)tryptophan and L-(β-11 C)DOPA intravenous injection was measured in twelve Rhesus monkeys using positron emission tomography (PET). The radiolabelled compounds were also injected together with various doses of unlabelled 5-hydroxy-L-tryptophan or L-DOPA. The radioactivity accumulated in the striatal region and the rate of increased utilization with time was calculated using a graphical method with back of the brain as a reference region. The rate constants for decarboxylation were 0.0070 ± 0.0007 (S. D) and 0.0121 ± 0.0010 min-1 for 5-hydroxy-L-(β-11 C)tryptophan and L-(β-11 C)DOPA, respectively. After concomitant injection with unlabelled 5-hydroxy-L-tryptophan, the rate constant of 5-hydroxy-L-(β-11 C)tryptophan decreased dose-dependently and a 50 percent reduction was seen with a dose of about 4 mg/kg of unlabelled compound. A decreased utilization rate of L-(β-11 C)DOPA was seen only after simultaneous injection of 30 mg/kg of either L-DOPA or 5-hydroxy-L-tryptophan. This capacity limitation was most likely interpreted as different affinity of the striatal aromatic amino acid decarboxylase for L-DOPA and 5-hydroxy-L-tryptophan, respectively

  17. Brain dopaminergic systems : imaging with positron tomography

    International Nuclear Information System (INIS)

    Imaging of the dopaminergic system in the human brain with the in vivo use of Positron Emission Tomography emerged in the late 1980s as a tool of major importance in clinical neurosciences and pharmacology. The last few years have witnessed rapid development of new radiotracers specific to receptors, reuptake sites and enzymes of the dopamine system; the application of these radiotracers has led to major break-troughs in the pathophysiology and therapy of movement disorders and schizophrenic-like psychoses. This book is the first to collect, in a single volume, state-of-the-art contributions to the various aspects of this research. Its contents address methodological issues related to the design, labelling, quantitative imaging and compartmental modeli-sation of radioligands of the post-synaptic, pre-synaptic and enzyme sites of the dopamine system and to their use in clinical research in the fields of Parkinson's disease as well as other movement disorders, psychoses and neuroleptic receptor occupancy. The chapters were written by leading European scientists in the field of PET, gathered together in Caen (France, November 1990) under the aegis of the EEC Concerted Action on PET Investigations of Cellular Regeneration and Degeneration. This book provides a current and comprehensive overview on PET studies of the brain dopamine system which should aid and interest neurologists , psychiatrists, pharmacologists and medical imaging scientists. (author). refs.; figs.; tabs

  18. Study of LAT1 Expression in Brain Metastases: Towards a Better Understanding of the Results of Positron Emission Tomography Using Amino Acid Tracers.

    Directory of Open Access Journals (Sweden)

    Caroline Papin-Michault

    Full Text Available Positron emission tomography using radiolabeled amino acid (PET-AA appears to be promising in distinguishing between recurrent tumour and radionecrosis in the follow-up of brain metastasis (BM. The amino acid transporter LAT1 and its cofactor CD98, which are involved in AA uptake, have never been investigated in BM. The aim of our study was to determine and compare the expression of LAT1 and CD98 in BM and in non-tumoral brain tissue (NT. The expression of LAT1 and CD98 were studied by immunohistochemistry in 67 BM, including 18 BM recurrences after radiotherapy, in 53 NT, and in 13 cases of patients with previously irradiated brain tumor and investigated by [18F] FDOPA-PET. LAT1 and CD98 expression were detected in 98.5% and 59.7% of BM respectively and were significantly associated with BM tissue as compared to NT (p<0.001. LAT1 expression in recurrent BM was significantly increased as compared to newly occurring BM. Ten cases investigated by [18F] FDOPA-PET corresponding to recurrent BM displayed significant [18F] FDOPA uptake and LAT1 overexpression whereas three cases corresponding to radionecrosis showed no or low uptake and LAT1 expression. LAT1 expression level and [18F] FDOPA uptake were significantly correlated. In conclusion, we hypothesized that BM may overexpress the AA transporter LAT1. We have shown that LAT1 overexpression was common in BM and was specific for BM as compared to healthy brain. These results could explain the specific BM uptake on PET-AA.

  19. Age- and Sex-Associated Changes in Cerebral Glucose Metabolism in Normal Healthy Subjects: Statistical Parametric Mapping Analysis of F-18 Fluorodeoxyglucose Brain Positron Emission Tomography

    International Nuclear Information System (INIS)

    Background: The age- and sex-associated changes of brain development are unclear and controversial. Several previous studies showed conflicting results of a specific pattern of cerebral glucose metabolism or no differences of cerebral glucose metabolism in association with normal aging process and sex. Purpose: To investigate the effects of age and sex on changes in cerebral glucose metabolism in healthy subjects using fluorine-18 fluorodeoxyglucose (F-18 FDG) brain positron emission tomography (PET) and statistical parametric mapping (SPM) analysis. Material and Methods: Seventy-eight healthy subjects (32 males, mean age 46.6±18.2 years; 46 females, mean age 40.6±19.8 years) underwent F-18 FDG brain PET. Using SPM, age- and sex-associated changes in cerebral glucose metabolism were investigated. Results: In males, a negative correlation existed in several gray matter areas, including the right temporopolar (Brodmann area [BA] 38), right orbitofrontal (BA 47), left orbitofrontal gyrus (BA 10), left dorsolateral frontal gyrus (BA 8), and left insula (BA 13) areas. A positive relationship existed in the left claustrum and left thalamus. In females, negative changes existed in the left caudate body, left temporopolar area (BA 38), right orbitofrontal gyri (BA 47 and BA 10), and right dorsolateral prefrontal cortex (BA 46). A positive association was demonstrated in the left subthalamic nucleus and the left superior frontal gyrus. In white matter, an age-associated decrease in FDG uptake in males was shown in the left insula, and increased FDG uptake was found in the left corpus callosum. The female group had an age-associated negative correlation of FDG uptake only in the right corpus callosum. Conclusion: Using SPM, we found not only similar areas of brain, but also sex-specific cerebral areas of age-associated changes of FDG uptake

  20. Age- and Sex-Associated Changes in Cerebral Glucose Metabolism in Normal Healthy Subjects: Statistical Parametric Mapping Analysis of F-18 Fluorodeoxyglucose Brain Positron Emission Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In-Ju; Kim, Seong-Jang; Kim, Yong-Ki (Dept. of Nuclear Medicine, Pusan National Univ. Hospital, Busan (Korea); Medical Research Institute, Pusan National Univ., Busan (Korea)). e-mail: growthkim@daum.net/growthkim@pusan.ac.kr)

    2009-12-15

    Background: The age- and sex-associated changes of brain development are unclear and controversial. Several previous studies showed conflicting results of a specific pattern of cerebral glucose metabolism or no differences of cerebral glucose metabolism in association with normal aging process and sex. Purpose: To investigate the effects of age and sex on changes in cerebral glucose metabolism in healthy subjects using fluorine-18 fluorodeoxyglucose (F-18 FDG) brain positron emission tomography (PET) and statistical parametric mapping (SPM) analysis. Material and Methods: Seventy-eight healthy subjects (32 males, mean age 46.6+-18.2 years; 46 females, mean age 40.6+-19.8 years) underwent F-18 FDG brain PET. Using SPM, age- and sex-associated changes in cerebral glucose metabolism were investigated. Results: In males, a negative correlation existed in several gray matter areas, including the right temporopolar (Brodmann area [BA] 38), right orbitofrontal (BA 47), left orbitofrontal gyrus (BA 10), left dorsolateral frontal gyrus (BA 8), and left insula (BA 13) areas. A positive relationship existed in the left claustrum and left thalamus. In females, negative changes existed in the left caudate body, left temporopolar area (BA 38), right orbitofrontal gyri (BA 47 and BA 10), and right dorsolateral prefrontal cortex (BA 46). A positive association was demonstrated in the left subthalamic nucleus and the left superior frontal gyrus. In white matter, an age-associated decrease in FDG uptake in males was shown in the left insula, and increased FDG uptake was found in the left corpus callosum. The female group had an age-associated negative correlation of FDG uptake only in the right corpus callosum. Conclusion: Using SPM, we found not only similar areas of brain, but also sex-specific cerebral areas of age-associated changes of FDG uptake

  1. Positron emission tomography in epilepsy

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) was performed with the 18F-fluoro-deoxy-glucose method on 29 patients with epilepsy (generalized epilepsy, 4; partial epilepsy, 24; undetermined type, 1). The subjects were restricted to patients with epilepsy without focal abnormality on X-CT. All the patients with generalized epilepsy showed a normal pattern on PET. Fourteen out of the 24 patients with partial epilepsy and the 1 with epilepsy of undermined type showed focal hypometabolism on PET. The hypometabolic zone was localized in areas including the temporal cortex in 11 patients, frontal in 2 and thalamus in 1. The location of hypometabolic zone and that of interictal paroxysmal activity on EEG were well correlated in most patients. The patients with poorly-controlled seizure showed a higher incidence of PET abnormality (12 out of 13) than those with well-controlled seizures (2 out of 11). The incidence of abnormality on PET and MRI and the location of both abnormality were not necessarily coincident. These results indicated that the PET examination in epilepsy provides valuable information about the location of epileptic focus, and that the findings on PET in patients with partial epilepsy may be one of the good indicators about the intractability of partial epilepsy, and that PET and MRI provide complementary information in the diagnosis of epilepsy. (author)

  2. A Case of Corticobasal Degeneration Studied with Positron Emission Tomography

    OpenAIRE

    Nagasawa, H; T. Imamura; Nomura, H; Itoh, M; Ido, T.

    1993-01-01

    We measured cerebral blood flow, oxygen metabolism, glucose utilization, and dopamine metabolism in the brain of a patient with corticobasal degeneration using positron emission tomography (PET). The clinical picture is distinctive, comprising features referable to both cortical and basal ganglionic dysfunction. Brain imagings of glucose and dopamine metabolism can demonstrate greater abnormalities in the cerebral cortex and in the striatum contralateral to the more affected side than those o...

  3. Physiologic signal detection in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography enables the noninvasive quantification in vivo of three-dimensional radionuclide distributions throughout the human body. Estimation of neurotransmitter and receptor function is performed through the application of tracer kinetic models and non-linear multiple regression parameter estimation methods. These quantitative estimates are often limited by the interaction between imaging characteristics of the PET scanner and the three-dimensional radionuclide distribution within the organ of interest. In order to assess the potential of PET to detect subtle changes in the function of the central nervous system, a three-dimensional PET simulation procedure based upon a digital brain phantom and tomograph detector response functions has been performed. Radiopharmaceutical kinetics for individual structures of the brain phantom (cortex, white matter, basal ganglia, etc.) have been assigned based upon in vitro autoradiography of human postmortem tissue and animal biodistribution studies. The recovery of the PET signals which originate from anatomic structures of interest has been evaluated for studies of the benzodiazepine, muscarinic, opiate, and GABA systems of the human brain. Typical results and the limitations of signal detection in PET neurotransmitter and receptor studies are discussed

  4. A New Brain Positron Emission Tomography Scanner With Semiconductor Detectors for Target Volume Delineation and Radiotherapy Treatment Planning in Patients With Nasopharyngeal Carcinoma

    International Nuclear Information System (INIS)

    Purpose: We compared two treatment planning methods for stereotactic boost for treating nasopharyngeal carcinoma (NPC): the use of conventional whole-body bismuth germanate (BGO) scintillator positron emission tomography (PETCONVWB) versus the new brain (BR) PET system using semiconductor detectors (PETNEWBR). Methods and Materials: Twelve patients with NPC were enrolled in this study. [18F]Fluorodeoxyglucose-PET images were acquired using both the PETNEWBR and the PETCONVWB system on the same day. Computed tomography (CT) and two PET data sets were transferred to a treatment planning system, and the PETCONVWB and PETNEWBR images were coregistered with the same set of CT images. Window width and level values for all PET images were fixed at 3000 and 300, respectively. The gross tumor volume (GTV) was visually delineated on PET images by using either PETCONVWB (GTVCONV) images or PETNEWBR (GTVNEW) images. Assuming a stereotactic radiotherapy boost of 7 ports, the prescribed dose delivered to 95% of the planning target volume (PTV) was set to 2000 cGy in 4 fractions. Results: The average absolute volume (±standard deviation [SD]) of GTVNEW was 15.7 ml (±9.9) ml, and that of GTVCONV was 34.0 (±20.5) ml. The average GTVNEW was significantly smaller than that of GTVCONV (p = 0.0006). There was no statistically significant difference between the maximum dose (p = 0.0585) and the mean dose (p = 0.2748) of PTV. The radiotherapy treatment plan based on the new gross tumor volume (PLANNEW) significantly reduced maximum doses to the cerebrum and cerebellum (p = 0.0418) and to brain stem (p = 0.0041). Conclusion: Results of the present study suggest that the new brain PET system using semiconductor detectors can provide more accurate tumor delineation than the conventional whole-body BGO PET system and may be an important tool for functional and molecular radiotherapy treatment planning.

  5. (/sup 11/C)clorgyline and (/sup 11/C)-L-deprenyl and their use in measuring functional monoamine oxidase activity in the brain using positron emission tomography

    Science.gov (United States)

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

    1986-04-17

    This invention involves a new strategy for imaging the activity of the enzyme monoamine oxidase in the living body by using /sup 11/C-labeled enzyme inhibitors which bind irreversibly to an enzyme as a result of catalysis. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  6. Implementation and evaluation of a 3D one-step late reconstruction algorithm for 3D positron emission tomography brain studies using median root prior

    International Nuclear Information System (INIS)

    A fully three-dimensional (3D) one-step late (OSL), maximum a posteriori (MAP) reconstruction algorithm based on the median root prior (MRP) was implemented and evaluated for the reconstruction of 3D positron emission tomography (PET) studies. The algorithm uses the ordered subsets (OS) scheme for convergence acceleration and data update during iterations. The algorithm was implemented using the software package developed within the EU project PARAPET (www.brunel.ac.uk/ masrppet). The MRP algorithm was evaluated using experimental phantom and real 3D PET brain studies. Various experimental set-ups in terms of activity distribution and counting statistics were considered. The performance of the algorithm was assessed by calculating figures of merit such as: contrast, coefficient of variation, activity ratio between two regions and full width at half of maximum for resolution measurements. The performance of MRP was compared with that of 3D ordered subsets-expectation maximisation (OSEM) and 3D re-projection (3DRP) algorithms. In all the experimental situations considered, MRP showed: (1) convergence to a stable solution, (2) effectiveness in noise reduction, particularly for low statistics data, (3) good preservation of spatial details. Compared with the OSEM and 3DRP algorithms, MRP provides comparable or better results depending on the parameters used for the reconstruction of the images. (orig.)

  7. An in vivo study of the dopaminergic receptors in the brain of man using 11C-pimozide and positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography was used to establish the regional cerebral pharmacokinetics of a carbon 11-labelled neuroleptic, pimozide, in an attempt to observe its specific bonding to dopaminergic receptors in vivo. The 11C-pimozide kinetics were compared in two brain structures at the two ends of the dopaminergic receptor density scale: the striatum and cerebellum, very rich in and devoid of these receptors respectively. In 8 patients a significant radioactivity uptake was observed in the striatum as compared with the cerebellum, in agreement with in vivo studies on animals using tritiated pimozide. In 5 patients pre-treated by a therapeutic dose of a cold neuroleptic (haloperidol) this difference in kinetics no longer existed. Moreover no kinetic difference is observed, either before or after haloperidol administration, between the frontal cortex (relatively low in dopaminergic receptors) and cerebellum. These results strongly suggest that pharmacokinetic phenomena directly related to the specific bonding of 11C-pimozide on the striatal dopaminergic receptors are observable on man in vivo. This specific bonding however remains quantitatively weak as compared with the strong non-specific bonding

  8. Mapping adenosine A1 receptors in the cat brain by positron emission tomography with [11C]MPDX

    International Nuclear Information System (INIS)

    We evaluated the potential of [11C]MPDX as a radioligand for mapping adenosine A1 receptors in comparison with previously proposed [11C]KF15372 in cat brain by PET. Two tracers showed the same brain distribution. Brain uptake of [11C]MPDX (Ki=4.2 nM) was much higher and washed out faster than that of [11C]KF15372 (Ki=3.0 nM), and was blocked by carrier-loading or displaced with an A1 antagonist. The regional A1 receptor distribution evaluated with kinetic analysis is consistent with that previously measured in vitro. [11C]MPDX PET has a potential for mapping adenosine A1 receptors in brain

  9. Preoperative motor system brain mapping using positron emission tomography and statistical parametric mapping: hints on cortical reorganisation

    OpenAIRE

    Meyer, P; Sturz, L; Sabri, O.; Schreckenberger, M; Spetzger, U; Setani, K; Kaiser, H.; Buell, U

    2003-01-01

    Objectives: This study investigated the applicability of statistical parametric mapping (SPM) for analysing individual preoperative brain mapping studies in patients with cerebral mass lesions for neurosurgical planning. The study further investigated if hints on functional reorganisation processes can be found.

  10. Application of positron emission tomography in neurophysiology

    International Nuclear Information System (INIS)

    PET measures the distribution of positron-emitting radiotracers in the organs of living subjects, by means of the angular correlation of the gamma-rays originating from positron annihilation. The UBC/TRIUMF Program focusses the technique on measurements of brain physiology, and radio-labelled tracers have been developed for measurements of regional cerebral glucose metabolism, regional cerebral blood flow, regional synthesis of dopamine neurotransmitter, and regional density and kinetics of dopamine receptor sites. Data have been obtained on normal physiology, and deranged physiology in Alzheimer's disease, Huntington's disease, Parkinson's disease, and astrocytoma brain tumors undergoing pion radiation treatment

  11. Positron Emission Tomography studies with [C-11]PBR28 in the Healthy Rodent Brain : Validating SUV as an Outcome Measure of Neuroinflammation

    NARCIS (Netherlands)

    Toth, Miklos; Doorduin, Janine; Haggkvist, Jenny; Varrone, Andrea; Amini, Nahid; Halldin, Christer; Gulyas, Balazs

    2015-01-01

    Molecular imaging of the 18 kD Translocator protein (TSPO) with positron emission tomography (PET) is of great value for studying neuroinflammation in rodents longitudinally. Quantification of the TSPO in rodents is, however, quite challenging. There is no suitable reference region and the use of pl

  12. Astrocytosis precedes amyloid plaque deposition in Alzheimer APPswe transgenic mouse brain: a correlative positron emission tomography and in vitro imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Vieitez, Elena; Ni, Ruiqing; Voytenko, Larysa; Marutle, Amelia [Karolinska Institutet, Division of Translational Alzheimer Neurobiology, Centre for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Stockholm (Sweden); Gulyas, Balazs; Halldin, Christer [Karolinska Institutet, Centre for Psychiatric Research, Department of Clinical Neuroscience, Stockholm (Sweden); Nanyang Technological University, NTU - Imperial College, Lee Kong Chian School of Medicine, Singapore (Singapore); Toth, Miklos; Haeggkvist, Jenny [Karolinska Institutet, Centre for Psychiatric Research, Department of Clinical Neuroscience, Stockholm (Sweden); Nordberg, Agneta [Karolinska Institutet, Division of Translational Alzheimer Neurobiology, Centre for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Stockholm (Sweden); Karolinska University Hospital Huddinge, Department of Geriatric Medicine, Stockholm (Sweden)

    2015-04-17

    Pathological studies suggest that neuroinflammation is exacerbated by increased beta-amyloid (Aβ) levels in the brain early in Alzheimer's disease (AD). The time course and relationships between astrocytosis and Aβ deposition were examined using multitracer in vivo positron emission tomography (PET) imaging in an AD transgenic mouse model, followed by postmortem autoradiography and immunohistochemistry analysis. PET imaging with the amyloid plaque tracer {sup 11}C-AZD2184 and the astroglial tracer {sup 11}C-deuterium-L-deprenyl ({sup 11}C-DED) was carried out in APPswe mice aged 6, 8-15 and 18-24 months (4-6 animals/group) and in wild-type (wt) mice aged 8-15 and 18-24 months (3-6 animals/group). Tracer uptake was quantified by region of interest analysis using PMOD software and a 3-D digital mouse brain atlas. Postmortem brain tissues from the same APPswe and wt mice in all age groups were analysed for Aβ deposition and astrocytosis by in vitro autoradiography using {sup 3}H-AZD2184, {sup 3}H-Pittsburgh compound B (PIB) and {sup 3}H-L-deprenyl and immunostaining performed with antibodies for Aβ{sub 42} and glial fibrillary acidic protein (GFAP) in sagittal brain sections. {sup 11}C-AZD2184 PET retention in the cerebral cortices of APPswe mice was significantly higher at 18-24 months than in age-matched wt mice. Cortical and hippocampal {sup 11}C-DED PET binding was significantly higher at 6 months than at 8-15 months or 18-24 months in APPswe mice, and it was also higher than at 8-15 months in wt mice. In vitro autoradiography {sup 3}H-AZD2184 and {sup 3}H-PIB binding confirmed the in vivo findings with {sup 11}C-AZD2184 and demonstrated age-dependent increases in Aβ deposition in APPswe cortex and hippocampus. There were no significant differences between APPswe and wt mice in {sup 3}H-L-deprenyl autoradiography binding across age groups. Immunohistochemical quantification demonstrated more Aβ{sub 42} deposits in the cortex and hippocampus and more

  13. Astrocytosis precedes amyloid plaque deposition in Alzheimer APPswe transgenic mouse brain: a correlative positron emission tomography and in vitro imaging study

    International Nuclear Information System (INIS)

    Pathological studies suggest that neuroinflammation is exacerbated by increased beta-amyloid (Aβ) levels in the brain early in Alzheimer's disease (AD). The time course and relationships between astrocytosis and Aβ deposition were examined using multitracer in vivo positron emission tomography (PET) imaging in an AD transgenic mouse model, followed by postmortem autoradiography and immunohistochemistry analysis. PET imaging with the amyloid plaque tracer 11C-AZD2184 and the astroglial tracer 11C-deuterium-L-deprenyl (11C-DED) was carried out in APPswe mice aged 6, 8-15 and 18-24 months (4-6 animals/group) and in wild-type (wt) mice aged 8-15 and 18-24 months (3-6 animals/group). Tracer uptake was quantified by region of interest analysis using PMOD software and a 3-D digital mouse brain atlas. Postmortem brain tissues from the same APPswe and wt mice in all age groups were analysed for Aβ deposition and astrocytosis by in vitro autoradiography using 3H-AZD2184, 3H-Pittsburgh compound B (PIB) and 3H-L-deprenyl and immunostaining performed with antibodies for Aβ42 and glial fibrillary acidic protein (GFAP) in sagittal brain sections. 11C-AZD2184 PET retention in the cerebral cortices of APPswe mice was significantly higher at 18-24 months than in age-matched wt mice. Cortical and hippocampal 11C-DED PET binding was significantly higher at 6 months than at 8-15 months or 18-24 months in APPswe mice, and it was also higher than at 8-15 months in wt mice. In vitro autoradiography 3H-AZD2184 and 3H-PIB binding confirmed the in vivo findings with 11C-AZD2184 and demonstrated age-dependent increases in Aβ deposition in APPswe cortex and hippocampus. There were no significant differences between APPswe and wt mice in 3H-L-deprenyl autoradiography binding across age groups. Immunohistochemical quantification demonstrated more Aβ42 deposits in the cortex and hippocampus and more GFAP+ reactive astrocytes in the hippocampus at 18-24 months than at 6 months in APPswe

  14. Evaluation of drug penetration into the brain: a double study by in vivo imaging with positron emission tomography and using an in vitro model of the human blood-brain barrier

    International Nuclear Information System (INIS)

    The blood brain barrier (BBB) passage of a set of radiopharmaceuticals candidates was measured both in vitro using a newly developed co-culture based model of human BBB and in vivo by positron emission tomography (PET). MATERIAL and METHODS: As an in vitro BBB model, a co-culture of primary human brain endothelial cells and primary human astrocytes was used. Dynamic PET studies were performed simultaneously on 4 anesthetized rats with the EXACT HR+ camera. Volumes of interest (VOI) were manually defined on the tomographic images in order to determine the pharmacokinetics of the compounds in various organs, including brain. The in vivo input function was measured by radioactivity counting of arterial blood samples. A two-compartment model analysis was used to compute the exchanging rate constants between blood and brain and to calculate the in vivo permeability coefficient. RESULTS: There was an excellent correlation between the in vitro and in vivo permeability coefficients (r = 0.99; p < 0.001) as well as between the in vivo distribution volume and the in vitro efflux /influx permeability coefficients ratio (r = 0.76). CONCLUSION: This double study evidenced a close relationship between the in vitro and the in vivo approaches for the assessment of the BBB passage. Hence, small animal PET imaging appeared suitable to screen drugs or radiopharmaceuticals candidates aimed at cerebral targets directly in the real-life situation in vivo. (author)

  15. ROC [Receiver Operating Characteristics] study of maximum likelihood estimator human brain image reconstructions in PET [Positron Emission Tomography] clinical practice

    International Nuclear Information System (INIS)

    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 18F -- 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Llacer, J.; Veklerov, E.; Nolan, D. (Lawrence Berkeley Lab., CA (USA)); Grafton, S.T.; Mazziotta, J.C.; Hawkins, R.A.; Hoh, C.K.; Hoffman, E.J. (California Univ., Los Angeles, CA (USA))

    1990-10-01

    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.

  17. A protocol for performing brain activation studies using 15O-water and Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    Full text: We are currently using 15O-water to measure regional cerebral blood flow (rCBF) and thus regional brain function in response to visual, sensorimotor and cognitive tasks in normal volunteers. This paper outlines the protocol used to perform such brain activation studies in our department. All subjects are required to give informed consent before the study. Subjects are positioned in the PET scanner with a face mask to reduce head movement. Head tilt is set by alignment along the superior orbito-mid-meatal line. An intravenous line is placed in the arm for the infusion of 15O-water. Subjects perform simple tasks in response to visual, auditory or cognitive stimuli. During each task 370 MBq of 15O-water is infused as a slow bolus (360 mL/h for 50 s) to the patient via the 15O-water generator. PET scanning is undertaken in septa-retracted or 3-D mode and proceeds for two minutes after the infusion. A total of 12 scans (six activation and six baseline) are acquired for each subject, with eight minute delays between successive studies to allow for decay of the tracer from the preceding scan. The acquisition protocol consists of the following: (1) A rectilinear scan to ensure the brain volume is centred in the field of view. (2) A ten-minute transmission scan. (3) A three-minute test 3-D acquisition (150 MBq of 15O-water) to determine the time delay between the commencement of infusion and the arrival of the tracer in the brain. (4) Twelve three-frame dynamic acquisitions (one 30-second and two 60-second frames). A statistical parametric mapping (SPM) data analysis program is then used to identify areas of brain activation

  18. Ionization and positron emission in giant quasiatoms

    International Nuclear Information System (INIS)

    Electron excitation processes in superheavy quasiatoms are treated within a relativistic framework. Theoretical results on K-hole production rates as well as delta-electron and positron spectra are compared with experimental data. It is demonstrated that the study of heavy ion collisions with nuclear time delay promises a signature for the spontaneous positron formation in overcritical systems. Corresponding experimental results are confronted with our theoretical hypothesis. Recent speculations on the origin of the observed peak structures in positron spectra are critically reviewed. Atomic excitations are also employed to obtain information on the course of a nuclear reaction. Using a semiclassical picture we calculate the emission of delta-electrons and positrons in deep-inelastic nuclear reactions. Furthermore some consequences of conversion processes in giant systems are investigated. (orig.)

  19. Positron emission tomography imaging of gene expression

    International Nuclear Information System (INIS)

    The merging of molecular biology and nuclear medicine is developed into molecular nuclear medicine. Positron emission tomography (PET) of gene expression in molecular nuclear medicine has become an attractive area. Positron emission tomography imaging gene expression includes the antisense PET imaging and the reporter gene PET imaging. It is likely that the antisense PET imaging will lag behind the reporter gene PET imaging because of the numerous issues that have not yet to be resolved with this approach. The reporter gene PET imaging has wide application into animal experimental research and human applications of this approach will likely be reported soon

  20. Asymmetric Synthesis of Spirocyclic 2-Benzopyrans for Positron Emission Tomography of σ1 Receptors in the Brain

    Directory of Open Access Journals (Sweden)

    Katharina Holl

    2014-01-01

    Full Text Available Sharpless asymmetric dihydroxylation of styrene derivative 6 afforded chiral triols (R-7 and (S-7, which were cyclized with tosyl chloride in the presence of Bu2SnO to provide 2-benzopyrans (R-4 and (S-4 with high regioselectivity. The additional hydroxy moiety in the 4-position was exploited for the introduction of various substituents. Williamson ether synthesis and replacement of the Boc protective group with a benzyl moiety led to potent σ1 ligands with high σ1/σ2-selectivity. With exception of the ethoxy derivative 16, the (R-configured enantiomers represent eutomers with eudismic ratios of up to 29 for the ester (R-18. The methyl ether (R-15 represents the most potent σ1 ligand of this series of compounds, with a Ki value of 1.2 nM and an eudismic ratio of 7. Tosylate (R-21 was used as precursor for the radiosynthesis of [18F]-(R-20, which was available by nucleophilic substitution with K[18F]F K222 carbonate complex. The radiochemical yield of [18F]-(R-20 was 18%–20%, the radiochemical purity greater than 97% and the specific radioactivity 175–300 GBq/µmol. Although radiometabolites were detected in plasma, urine and liver samples, radiometabolites were not found in brain samples. After 30 min, the uptake of the radiotracer in the brain was 3.4% of injected dose per gram of tissue and could be reduced by coadministration of the σ1 antagonist haloperidol. [18F]-(R-20 was able to label those regions of the brain, which were reported to have high density of σ1 receptors.

  1. Efficacy of 68Ga-DOTATOC Positron Emission Tomography (PET) CT in Children and Young Adults With Brain Tumors

    Science.gov (United States)

    2016-06-17

    Acoustic Schwannoma; Adult Anaplastic Astrocytoma; Adult Anaplastic Ependymoma; Adult Anaplastic Meningioma; Adult Anaplastic Oligodendroglioma; Adult Brain Stem Glioma; Adult Choroid Plexus Tumor; Adult Craniopharyngioma; Adult Diffuse Astrocytoma; Adult Ependymoblastoma; Adult Ependymoma; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Adult Grade I Meningioma; Adult Grade II Meningioma; Adult Medulloblastoma; Adult Meningeal Hemangiopericytoma; Adult Mixed Glioma; Adult Myxopapillary Ependymoma; Adult Oligodendroglioma; Adult Papillary Meningioma; Adult Pilocytic Astrocytoma; Adult Pineal Gland Astrocytoma; Adult Pineoblastoma; Adult Pineocytoma; Adult Subependymal Giant Cell Astrocytoma; Adult Subependymoma; Adult Supratentorial Primitive Neuroectodermal Tumor (PNET); Childhood Choroid Plexus Tumor; Childhood Craniopharyngioma; Childhood Ependymoblastoma; Childhood Grade I Meningioma; Childhood Grade II Meningioma; Childhood Grade III Meningioma; Childhood High-grade Cerebellar Astrocytoma; Childhood High-grade Cerebral Astrocytoma; Childhood Infratentorial Ependymoma; Childhood Low-grade Cerebellar Astrocytoma; Childhood Low-grade Cerebral Astrocytoma; Childhood Medulloepithelioma; Childhood Supratentorial Ependymoma; Meningeal Melanocytoma; Newly Diagnosed Childhood Ependymoma; Recurrent Adult Brain Tumor; Recurrent Childhood Anaplastic Astrocytoma; Recurrent Childhood Anaplastic Oligoastrocytoma; Recurrent Childhood Anaplastic Oligodendroglioma; Recurrent Childhood Brain Stem Glioma; Recurrent Childhood Cerebellar Astrocytoma; Recurrent Childhood Cerebral Astrocytoma; Recurrent Childhood Diffuse Astrocytoma; Recurrent Childhood Ependymoma; Recurrent Childhood Fibrillary Astrocytoma; Recurrent Childhood Gemistocytic Astrocytoma; Recurrent Childhood Giant Cell Glioblastoma; Recurrent Childhood Glioblastoma; Recurrent Childhood Gliomatosis Cerebri; Recurrent Childhood Gliosarcoma; Recurrent Childhood Medulloblastoma; Recurrent Childhood

  2. Cu-64-pyruvaldehyde-bis-(N4-methylthiosemicarbazide) or Cu-64-PTSM as tracer for brain positron emission tomography

    International Nuclear Information System (INIS)

    Synthesis of pyruvaldehyde-bis-(N4-methylthiosemicarbazide) (PTSM), used for medical investigation and diagnosis, has been carried out in our Radiopharmaceutical Division in C.A.E. (Ezeiza Atomic Center). PTSM has been obtained introducing modifications to a previous synthesis published by H.G. Petering. (M.P. 236-238 degrees C). TLC, HPLC and IR spectrum controls have been performed. Cu-64 can be obtained by the Cu-63(n,α) and Zn-64(n,p) reactions. This last reaction has been chosen for the production in the RA-3 reactor since it leads to Cu-64 of high specific activity. Two different assays have been performed to obtain the chelate PTSM-Cu-64. The first one has been obtained by buffering the Cu-64 to pH 3-4; adding the PTSM solution to ethanol. The second assay has been carried out by buffering the Cu-64 solution with sodium acetate 3M and adding 100 μl of PTSM solution. Biodistribution studies have been carried out on NIH and rats showing a brain uptake of 4%, 30 minutes after injection. Thus, PTSM-Cu-64 proves a good brain diagnosis agent. (author). 1 ref

  3. Development a method of clustering multiple functional coupling in hemodynamic disease of the brain with positron emission tomography

    International Nuclear Information System (INIS)

    Aim: We have investigated post operative changes in CBF and vasodilative and vasoconstrictive reactions for an individual patient with cerebrovascular disease (CVD), by means of segmenting the brain image into some clusters with the varied combination of multiple cerebral functions. In this study, we have developed a new method to classify the combination of the multiple functions by using the common mutual information space generated from the PET images for all subjects. Materials and Methods: Four patients with CVD (two Moyamoya disease and two ICA occlusion) underwent PET CBF imaging with [15O] labeled water at conditions of rest, hyper ventilation and acetazolamide loading pre- and post-operation. A mutual information space for all subjects was generated by plotting the values of resting CBF, HV CBF (CBF in hyper ventilation - resting CBF), and AZ CBF (CBF in acetazolamide loading - resting CBF) at the same pixel in the cerebral cortex images for three axes. The space was classified into six segments by hierarchical cluster analysis method. A segmented brain map was created at each study. The characteristic of each segment was described as the mean value of resting CBF, HV and AZ responses as shown in the right side of a figure (no. 6: normal, no. 1: decreased CBF and responses). Results: The segments belonging to the images at pre- and post- operation for each patient are shown in the left of the figure. A closed circle shows a region including operated lesion. In a case 3 with ICA occlusion, the brain map was classified into three segments, that is no. 2 ischemic region with decreased resting CBF and poor vaso-reactivity, no. 6=normal region, no. 5=decreased resting CBF with high vaso-reactivity before operation. Segments of no. 2 turned into no. 3 and no. 4 and segment of no. 5 turned into normal (no. 6) 3 months after operation as shown in arrows of the figure. The map 11 months post operation consists of normal function (no. 6) only. Conclusion: This

  4. Beyond FDG positron emission tomography imaging

    International Nuclear Information System (INIS)

    At present, positron emission tomography/computed tomography (PET/CT) is one of the most rapidly growing areas of medical imaging, with many applications in the clinical management of patients with cancer. Although ((18)F) fluorodeoxyglucose (FDG)-PET/CT imaging provides high specificity and sensitivity in several kinds of cancer and has many applications, it is important to recognize that FDG is not a 'specific' radiotracer for imaging malignant disease. Highly 'tumor-specific' PET radiopharmaceuticals are essential to meet the growing demand of radioisotope-based molecular imaging technology. C-11 Methionine PET has been used to better define the radiotherapy field both for CNS tumors and head and neck (H and N) tumors to localize the most metabolic area inside a brain mass to guide the biopsy or in early evaluation of radiotherapy effect on H and N cancer. Flurodihydroxyphenylalanine (FDOPA) is an aromatic amino acid labelled with 18F. Besides it has also been introduced into oncological practice, in particular for malignant tumors of neural crest origin

  5. Advanced instrumentation for Positron Emission Tomography

    International Nuclear Information System (INIS)

    This paper summarizes the physical processes and medical science goals that underly modern instrumentation design for Positron Emission Tomography. The paper discusses design factors such as detector material, crystalphototube coupling, shielding geometry, sampling motion, electronics design, time-of-flight, and the interrelationships with quantitative accuracy, spatial resolution, temporal resolution, maximum data rates, and cost. 71 refs., 3 figs., 3 tabs

  6. Advanced Instrumentation for Positron Emission Tomography [PET

    Science.gov (United States)

    Derenzo, S. E.; Budinger, T. F.

    1985-04-01

    This paper summarizes the physical processes and medical science goals that underlay modern instrumentation design for Positron Emission Tomography. The paper discusses design factors such as detector material, crystalphototube coupling, shielding geometry, sampling motion, electronics design, time-of-flight, and the interrelationships with quantitative accuracy, spatial resolution, temporal resolution, maximum data rates, and cost.

  7. Imaging of amyloid deposition in human brain using positron emission tomography and [{sup 18}F]FACT: comparison with [{sup 11}C]PIB

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi [National Institute of Radiological Sciences, Molecular Imaging Center, Chiba (Japan); National Institute of Radiological Sciences, Biophysics Program, Molecular Imaging Center, Chiba (Japan); Shinotoh, Hitoshi; Shimada, Hitoshi; Miyoshi, Michie; Takano, Harumasa; Takahashi, Hidehiko; Arakawa, Ryosuke; Kodaka, Fumitoshi; Ono, Maiko; Eguchi, Yoko; Higuchi, Makoto; Fukumura, Toshimitsu; Suhara, Tetsuya [National Institute of Radiological Sciences, Molecular Imaging Center, Chiba (Japan); Yanai, Kazuhiko; Okamura, Nobuyuki [Tohoku University School of Medicine, Department of Pharmacology, Sendai (Japan)

    2014-04-15

    The characteristic neuropathological changes in Alzheimer's disease (AD) are deposition of amyloid senile plaques and neurofibrillary tangles. The {sup 18}F-labeled amyloid tracer, [{sup 18}F]2-[(2-{(E)-2-[2-(dimethylamino)-1,3-thiazol-5-yl]vinyl}-1, 3-benzoxazol-6-yl)oxy ]-3-fluoropropan-1-ol (FACT), one of the benzoxazole derivatives, was recently developed. In the present study, deposition of amyloid senile plaques was measured by positron emission tomography (PET) with both [ {sup 11}C ]Pittsburgh compound B (PIB) and [ {sup 18}F ]FACT in the same subjects, and the regional uptakes of both radiotracers were directly compared. Two PET scans, one of each with [ {sup 11}C ]PIB and [ {sup 18}F ]FACT, were performed sequentially on six normal control subjects, two mild cognitive impairment (MCI) patients, and six AD patients. The standardized uptake value ratio of brain regions to the cerebellum was calculated with partial volume correction using magnetic resonance (MR) images to remove the effects of white matter accumulation. No significant differences in the cerebral cortical uptake were observed between normal control subjects and AD patients in [ {sup 18}F ]FACT studies without partial volume correction, while significant differences were observed in [ {sup 11}C ]PIB. After partial volume correction, the cerebral cortical uptake was significantly larger in AD patients than in normal control subjects for [ {sup 18}F ]FACT studies as well as [ {sup 11}C ]PIB. Relatively lower uptakes of [ {sup 11}C ]PIB in distribution were observed in the medial side of the temporal cortex and in the occipital cortex as compared with [ {sup 18}F ]FACT. Relatively higher uptake of [ {sup 11}C ]PIB in distribution was observed in the frontal and parietal cortices. Since [ {sup 18}F ]FACT might bind more preferentially to dense-cored amyloid deposition, regional differences in cerebral cortical uptake between [ {sup 11}C ]PIB and [ {sup 18}F ]FACT might be due to differences

  8. A comparison study of 11C-methionine and 18F-fluorodeoxyglucose positron emission tomography-computed tomography scans in evaluation of patients with recurrent brain tumors

    Science.gov (United States)

    Sharma, Rajnish; D’Souza, Maria; Jaimini, Abhinav; Hazari, Puja Panwar; Saw, Sanjeev; Pandey, Santosh; Singh, Dinesh; Solanki, Yachna; Kumar, Nitin; Mishra, Anil K.; Mondal, Anupam

    2016-01-01

    Introduction: 11C-methonine ([11C]-MET) positron emission tomography-computed tomography (PET-CT) is a well-established technique for evaluation of tumor for diagnosis and treatment planning in neurooncology. [11C]-MET reflects amino acid transport and has been shown to be more sensitive than magnetic resonance imaging (MRI) in stereotactic biopsy planning. This study compared fluorodeoxyglucose (FDG) PET-CT and MET PET-CT in the detection of various brain tumors. Materials and Methods: Sixty-four subjects of brain tumor treated by surgery, chemotherapy, and/or radiotherapy were subjected to [18F]-FDG, [11C]-MET, and MRI scan. The lesion was analyzed semiquantitatively using tumor to normal contralateral ratio. The diagnosis was confirmed by surgery, stereotactic biopsy, clinical follow-up, MRI, or CT scans. Results: Tumor recurrence was found in 5 out of 22 patients on [F-18] FDG scan while [11C]-MET was able to detect recurrence in 18 out of 22 patients in low-grade gliomas. Two of these patients were false positive for the presence of recurrence of tumor and later found to be harboring necrosis. Among oligodendroglioma, medulloblastoma and high-grade glioma out of 42 patients 39 were found to be concordant MET and FDG scans. On semiquantitative analysis, mean T/NT ratio was found to be 2.96 ± 0.94 for lesions positive for recurrence of tumors and 1.18 ± 0.74 for lesions negative for recurrence of tumor on [11C]-MET scan. While the ratio for FDG scan on semiquantitative analysis was found to be 2.05 ± 1.04 for lesions positive for recurrence of tumors and 0.52 ± 0.15 for lesions negative for recurrence of tumors. Conclusion: The study highlight that [11C]-MET is superior to [18F]-FDG PET scans to detect recurrence in low-grade glioma. A cut-off value of target to nontarget value of 1.47 is a useful parameter to distinguish benign from malignant lesion on an [11C]-MET Scan. Both [18F]-FDG and [11C]-MET scans were found to be useful in high-grade astrocytoma

  9. Imaging of amyloid deposition in human brain using positron emission tomography and [18F]FACT: comparison with [11C]PIB

    International Nuclear Information System (INIS)

    The characteristic neuropathological changes in Alzheimer's disease (AD) are deposition of amyloid senile plaques and neurofibrillary tangles. The 18F-labeled amyloid tracer, [18F]2-[(2-{(E)-2-[2-(dimethylamino)-1,3-thiazol-5-yl]vinyl}-1, 3-benzoxazol-6-yl)oxy ]-3-fluoropropan-1-ol (FACT), one of the benzoxazole derivatives, was recently developed. In the present study, deposition of amyloid senile plaques was measured by positron emission tomography (PET) with both [ 11C ]Pittsburgh compound B (PIB) and [ 18F ]FACT in the same subjects, and the regional uptakes of both radiotracers were directly compared. Two PET scans, one of each with [ 11C ]PIB and [ 18F ]FACT, were performed sequentially on six normal control subjects, two mild cognitive impairment (MCI) patients, and six AD patients. The standardized uptake value ratio of brain regions to the cerebellum was calculated with partial volume correction using magnetic resonance (MR) images to remove the effects of white matter accumulation. No significant differences in the cerebral cortical uptake were observed between normal control subjects and AD patients in [ 18F ]FACT studies without partial volume correction, while significant differences were observed in [ 11C ]PIB. After partial volume correction, the cerebral cortical uptake was significantly larger in AD patients than in normal control subjects for [ 18F ]FACT studies as well as [ 11C ]PIB. Relatively lower uptakes of [ 11C ]PIB in distribution were observed in the medial side of the temporal cortex and in the occipital cortex as compared with [ 18F ]FACT. Relatively higher uptake of [ 11C ]PIB in distribution was observed in the frontal and parietal cortices. Since [ 18F ]FACT might bind more preferentially to dense-cored amyloid deposition, regional differences in cerebral cortical uptake between [ 11C ]PIB and [ 18F ]FACT might be due to differences in regional distribution between diffuse and dense-cored amyloid plaque shown in the autoradiographic

  10. Cerebral circulation and metabolism in the patients with higher brain dysfunction caused by chronic minor traumatic brain injury. A study by the positron emission tomography in twenty subjects with normal MRI findings

    International Nuclear Information System (INIS)

    Many individuals are affected on their higher brain functions, such as intelligence, memory, and attention, even after minor traumatic brain injury (MTBI). Although higher brain dysfunction is based on impairment of the cerebral circulation and metabolism, the precise relationship between them remains unknown. This study was undertaken to investigate the relationship between the cerebral circulation or cerebral metabolism and higher brain dysfunction. Twenty subjects with higher brain dysfunction caused by chronic MTBI were studied. They had no abnormal MRI findings. The full-scale intelligence quotient (FIQ) were quantitatively evaluated by the Wechsler Adult Intelligence Scale-Revised (WAIS-R), and the subjects were classified into the normal group and the impaired group. Concurrent with the evaluation of FIQ, positron emission tomography (PET) was performed by the steady state method with 15O gases inhalation. Regional cerebral blood flow (rCBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) were calculated in the bilateral frontal, parietal, temporal, and occipital lobe. First, of all twenty subjects, we investigated rCBF, OEF and CMRO2 in all regions. Then we compared rCBF, OEF, and CMRO2 between the normal group and the impaired group based on FIQ score. We also studied the change of FIQ score of 13 subjects 9.3 months after the first evaluation. In addition, we investigated the change of rCBF, OEF and CMRO2 along with the improvement of FIQ score. Although rCBF and OEF of all subjects were within the normal range in all regions, CMRO2 of more than half of subjects was under the lower normal limit in all regions except in the right occipital lobe, showing the presence of ''relative luxury perfusion''. Comparison of rCBF, OEF and CMRO2 between normal group and impaired group revealed that CMRO2 of the impaired group was significantly lower than that of the normal group in the bilateral frontal, temporal, and occipital lobe

  11. Clinical impact of 18F-fluorodeoxyglucose positron emission tomography in the diagnosis of neurological diseases

    International Nuclear Information System (INIS)

    In this review it will be discussed in which neurological disorders positron emission tomography can yield important diagnostic information. Because positron emission tomography is an expensive method indications have to be cleary defined. One important question concerns the differentiation of tumor recurrence and scar due to radiation therapy or an operation. The grading of brain tumors is another application. In HIV patients fluorodeoxyglucose positron emission tomography can separate lymphoma and toxoplasmosis. In the evaluation of dementia positron emission tomography can help to clarify the differential diagnosis. Another important area is the presurgical evaluation of epilepsy patients and patients with cerebrovascular disease in whom a surgical revascularization procedure is planned. In extrapyramidal disorders, positron emission tomography can often help to establish the final diagnosis. (author)

  12. Positron Scanner for Locating Brain Tumors

    Science.gov (United States)

    Rankowitz, S.; Robertson, J. S.; Higinbotham, W. A.; Rosenblum, M. J.

    1962-03-01

    A system is described that makes use of positron emitting isotopes for locating brain tumors. This system inherently provides more information about the distribution of radioactivity in the head in less time than existing scanners which use one or two detectors. A stationary circular array of 32 scintillation detectors scans a horizontal layer of the head from many directions simultaneously. The data, consisting of the number of counts in all possible coincidence pairs, are coded and stored in the memory of a Two-Dimensional Pulse-Height Analyzer. A unique method of displaying and interpreting the data is described that enables rapid approximate analysis of complex source distribution patterns. (auth)

  13. Positron emission tomography of the lung

    International Nuclear Information System (INIS)

    Positron emission tomography enables the distribution of positron emitting isotopes to be imaged in a transverse plane through the body and the regional concentration of the isotope to be measured quantitatively. This thesis reports some applications of positron emission tomography to studies of pulmonary pathophysiology. Measurements in lung phantoms showed that regional lung density could be measured from a transmission tomogram obtained with an external source of positron emitting isotope. The regional, fractional blood volume was measured after labelling the blood with carbon-11-monoxide. Regional extravascular lung density (lung tissue and interstitial water per unit thoracic volume) was obtained by subtracting fractional blood volume from lung density. Measurements in normal subjects revealed large regional variations in lung density and fractional blood volume in the supine posture. Extravascular lung density showed a more uniform distribution. The technique has been used to study patients with chronic interstitial pulmonary oedema, pulmonary sarcoidosis and fibrosis, pulmonary arterial hypertension and patients with intracardiac, left-to-right shunt. Tomographic measurements of pulmonary tissue concentration of radionuclides are difficult, since corrections for the blood content and the inflation of the lung must be applied. A simultaneous measurement of lung density and fractional blood volume allows such corrections to be made and the extravascular tracer concentration to be calculated. This has been applied to measurements of the tissue penetration of carbon-11-labelled erythromycin in patients with lobar pneumonia. (author)

  14. Positron emission tomography in epilepsy

    International Nuclear Information System (INIS)

    Epilepsy is characterized by paroxysmal alterations in behavior and psychological functions, associated with increased neural discharge that is detectable by EEG. In between these paroxysmal events patients may appear superficially normal, but may have neurological signs and neurpsychological deficits. The neurological signs are sometimes correlated with radiologically detectable lesions, but there is little correlation between the CT abnormalities and the EEG focus, and CT abnormalities are rarely found in ''primary'' or ''idiopathic'' forms of epilepsy. Thus, seizure foci documented by ictal EEG can occur in regions that appear normal on CT. Since brain abnormalities implicated in epilepsy are more clearly reflected in measures of neural activity than in measures of anatomy, PET has particular potential for the study of epileptic pathophysiology. It provides the ability to measure local alterations in brain blood flow and metabolism, which are highly coupled with neural activity, and this makes possible the characterization of metabolic changes associated with epilepsy. Thus PET has the potential for contributing to the localization of epileptic activity as well as to the understanding of its pathophysiology

  15. Incidental colorectal polyps in positron emission tomography

    International Nuclear Information System (INIS)

    Fluorodeoxy glucose positron emission tomography/computed tomography (FDG PET/CT) is increasingly being used for diagnosing various malignancies and surveillance of cancer recurrence, staging and screening in high-risk individuals. Due to its high sensitivity in picking up small dysplastic lesions, incidental lesions are detected frequently. We present two patients who underwent PET CT as part of cancer screening and were incidentally detected with adenomatous colonic polyps. Colonoscopy and biopsy confirmed the diagnosis

  16. Positron emission tomography (PET) for cholangiocarcinoma

    OpenAIRE

    Breitenstein, S; Apestegui, C.; Clavien, P.-A.

    2008-01-01

    The combination of positron emission tomography (PET) with computed tomography (PET-CT) provides simultaneous metabolic and anatomic information on tumors in the same imaging session. Sensitivity of PET/PET-CT is higher for intrahepatic (>90%) than for extrahepatic cholangiocarcinoma (CCA) (about 60%). The detection rate of distant metastasis is 100%. PET, and particularly PET-CT, improves the results and impacts on the oncological management in CCA compared with other imaging modalities. The...

  17. Evaluation of mild hypothermia therapy for neonatal hypoxic-ischaemic encephalopathy on brain energy metabolism using 18F-fluorodeoxyglucose positron emission computed tomography

    OpenAIRE

    Luo, Mei; Li, Qingping; DONG, WENBIN; Zhai, Xuesong; Kang, Lan

    2014-01-01

    It remains unclear whether mild hypothermia affects energy metabolism in the brain tissue of newborns with hypoxic-ischaemic encephalopathy (HIE). The current study aimed to investigate the effect of mild hypothermia on energy metabolism in neonatal HIE and assess brain energy metabolism using position emission tomography/computed tomography (PET/CT) scanning. The mean standardised uptake values of 18F-fluorodeoxyglucose (18F-FDG) were used to determine the glucose metabolic rate in various b...

  18. Positron-emission tomography and cerebral metabolism

    International Nuclear Information System (INIS)

    In addition to the fact that radio-isotopes allow iso-atom labelling, they are short-lived and consequently may be injected into humans without serious problems of radiation damage. They disintegrate by emitting positrons which can be detected by external counting by virtue of the two 511 keV gamma rays emitted at the same time in opposite directions. These properties are used for tomographic detection and permit quantitative measurements of the radio-activity method will be described. The first concerns the transport of amino-acids into the brain, the second, the metabolism of psychoactive drugs. (orig./VJ)

  19. A comparative study in Alzheimer's and normal brains of trace element distribution using PIXE and INA analyses and glucose metabolism by positron emission tomography

    NARCIS (Netherlands)

    Cutts, DA; Maguire, RP; Stedman, JD; Leenders, KL; Spyrou, NM

    1999-01-01

    The onset of Alzheimer's disease has been shown to affect trace element concentrations in the brain when compared to "normal" subjects in ex vivo samples. The techniques used to determine trace element concentrations were proton-induced X-ray emission and instrumental neutron activation analysis. Wi

  20. Investigation of language lateralization mechanism by Positron Emission Tomography

    International Nuclear Information System (INIS)

    As language lateralization in the brain left hemisphere is one of the most well known but less understood characteristics of the human brain, this research thesis reports the use of brain functional imaging to address some specific aspects of this lateralization. In a first part, the author reports the study of mechanisms of recovery from aphasia after a left hemisphere lesion within a population of aphasic right-handers. Based on a contrast between patients with a persistent aphasia despite usual language therapies, and patients with a significant recovery after a melodic and rhythmic therapy (TMR), a PET-based (positron emission tomography) activation study has been developed, based on the opposition between usual language stimuli and stimuli accentuated by TMR. In the second part, the author explored more systematically on sane patients the influence of some physical characteristics of auditory stimulation on the induced functional asymmetry

  1. Human cerebral circulation. Positron emission tomography studies

    International Nuclear Information System (INIS)

    We reviewed the literature on human cerebral circulation and oxygen metabolism, as measured by positron emission tomography (PET), with respect to normal values and of regulation of cerebral circulation. A multicenter study in Japan showed that between-center variations in cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) values were not considerably larger than the corresponding within-center variations. Overall mean±SD values in cerebral cortical regions of normal human subjects were as follows: CBF=44.4±6.5 ml/100 ml/min; CBV=3.8±0.7 ml/100 ml; OEF=0.44±0.06; CMRO2=3.3±0.5 ml/100 ml/min (11 PET centers, 70 subjects). Intrinsic regulation of cerebral circulation involves several factors. Autoregulation maintains CBF in response to changes in cerebral perfusion pressure; chemical factors such as PaCO2 affect cerebral vascular tone and alter CBF; changes in neural activity cause changes in cerebral energy metabolism and CBF; neurogenic control of CBF occurs by sympathetic innervation. Regional differences in vascular response to changes in PaCO2 have been reported, indicating regional differences in cerebral vascular tone. Relations between CBF and CBV during changes in PaCO2 and during changes in neural activity were in good agreement with Poiseuille's law. The mechanisms of vascular response to neural activation and deactivation were independent on those of responses to PaCO2 changes. CBV in a brain region is the sum of three components: arterial, capillary and venous blood volumes. It has been reported that the arterial blood volume fraction is approximately 30% in humans and that changes in human CBV during changes in PaCO2 are caused by changes in arterial blood volume without changes in venous blood volume. These findings should be considered in future studies of the pathophysiology of cerebrovascular diseases. (author) 136 refs

  2. Positron Emission Tomography: Its 65 years

    Science.gov (United States)

    Del Guerra, A.; Belcari, N.; Bisogni, M.

    2016-04-01

    Positron Emission Tomography (PET) is a well-established imaging technique for in vivo molecular imaging. In this review after a brief history of PET there are presented its physical principles and the technology that has been developed for bringing PET from a bench experiment to a clinical indispensable instrument. The limitations and performance of the PET tomographs are discussed, both as for the hardware and software aspects. The status of art of clinical, pre-clinical and hybrid scanners (, PET/CT and PET/MR) is reported. Finally the actual trend and the recent and future technological developments are fully illustrated.

  3. Perspectives for positron emission tomography with RPCs

    International Nuclear Information System (INIS)

    In this study, we address the feasibility and main properties of a positron emission tomograph (PET) based on RPCs. The concept, making use of the converter-plate principle, takes advantage of the intrinsic layered structure of RPCs and its simple and economic construction. The extremely good time and position resolutions of RPCs also allow the TOF-PET imaging technique to be considered. Monte-Carlo simulations, supported by experimental data, are presented and the main advantages and drawbacks for applications of potential interest are discussed

  4. Positron Emission Tomography Imaging of Pancreatic Cancer

    Directory of Open Access Journals (Sweden)

    Saravanan Kokila Krishnamoorthy

    2014-03-01

    Full Text Available Positron emission tomography (PET using 18F-fluorodeoxyglucose (FDG is increasingly used for the staging of solidmalignancies, including lung and esophagus. However, controversy still exists in relation to the application of PET inpancreatic cancer. The authors review seven studies (Abstracts #183, #189, #190, #254, #357, #375, #378 presented at the2014 ASCO Gastrointestinal Cancers Symposium and discuss on the role of PET in this disease. As the limitations of theResponse Evaluation Criteria In Solid Tumors (RECIST continue to become evident, FDG-PET may identify changes in themetabolic activity within pancreatic adenocarcinoma, and can provide both diagnostic and prognostic information.

  5. Emission tomography of the brain

    International Nuclear Information System (INIS)

    Emission tomography (ET) is a method for visualization of radionuclide distribution in transaxial sections of a body region, especially the brain. Both single-photon emitting and positron emitting radionuclides may be utilized. Conventional radiopharmaceuticals are used for single-photon ET: it shows three-dimensional distribution of radionuclides in normal and pathological brain structures and, when fast scanning techniques are used, permits the quantitative measurement of flow in small brain regions without interference from overprojection of differently perfused tissues. Coincidence detection of short-lived positron emitting radionuclides has the advantage of good attenuation correction so that quantitative determination of the concentration of the radionuclide in small tissue volumes is possible. With these short-lived, usually cyclotron-produced radionuclides, dynamic and metabolic processes may be followed (e.g. regional oxygen consumption with 15O2, regional blood volume with 11CO, C15O or 68Ga, regional perfusion with 13NH3, C15O2or77Kr) and the consumption and distribution of labelled organic compounds may be quantified (e.g. local metabolic rate of glucose with 18F-deoxyglucose or glucose distribution with 11C-methylglucose). The clinical application of these techniques may render new insight into pathophysiological mechanisms and the therapeutic management of diseases of the central nervous system. (author)

  6. Positron emission tomography tracers for imaging angiogenesis

    International Nuclear Information System (INIS)

    Position emission tomography imaging of angiogenesis may provide non-invasive insights into the corresponding molecular processes and may be applied for individualized treatment planning of antiangiogenic therapies. At the moment, most strategies are focusing on the development of radiolabelled proteins and antibody formats targeting VEGF and its receptor or the ED-B domain of a fibronectin isoform as well as radiolabelled matrix metalloproteinase inhibitors or αvβ3 integrin antagonists. Great efforts are being made to develop suitable tracers for different target structures. All of the major strategies focusing on the development of radiolabelled compounds for use with positron emission tomography are summarized in this review. However, because the most intensive work is concentrated on the development of radiolabelled RGD peptides for imaging αvβ3 expression, which has successfully made its way from bench to bedside, these developments are especially emphasized. (orig.)

  7. [Basic principles of 18F-fluorodeoxyglucose positron emission tomography].

    Science.gov (United States)

    Standke, R

    2002-01-01

    Positron emission tomography uses photons to receive regional information about dynamic, physiologic, and biochemical processes in the living body. A positron decay is measured indirectly by the simultaneous registration of both gamma rays created by the annihilation. The event is counted, if two directly opposite located detectors register gamma rays in coincidence. Unfortunately the detectors of a positron emission tomography system do not register only true coincident events. There are also scattered and random coincidences. Different types of positron tomographs are presented and scintillation crystals, which are in use for positron emission tomography are discussed. The 2D- and 3D-acquisition methods are described as well as preprocessing methods, such as correction for attenuation, scatter and dead time. For quantification the relative parameter standard uptake value (SUV) is explained. Finally hybrid systems, such as combined positron emission tomography/computed tomography scanners and the use of computed tomography data for attenuation correction are introduced. PMID:12506765

  8. In vivo monitoring of tissue function and metabolism using positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) relies on a combination of the use of positron-emitting radioactive tracers and computerized tomography to monitor certain physiological and functional characteristics in vivo and noninvasively. Its special and most powerful applications to date are in brain physiology and neurology. There are many potential research applications in farm animals, such as the mapping of neuro-humoral pathways, but cost and the need for special facilities are likely to be prohibitive

  9. 77 FR 8262 - Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Science.gov (United States)

    2012-02-14

    ... Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice... entitled ``Investigational New Drug Applications for Positron Emission Tomography (PET) Drugs.'' The draft... Applications for Positron Emission Tomography (PET) drugs.'' The draft guidance summarizes the IND process...

  10. Positron emission tomography: radioisotope and radiopharmaceutical production

    International Nuclear Information System (INIS)

    A Centre for Positron Emission Tomography (PET) has been operational within the Department of Nuclear Medicine at the Austin and Repatriation Medical Centre (A and RMC) in Melbourne for seven years. PET is a non-invasive imaging technique based on the use of biologically relevant compounds labelled with short-lived positron-emitting radionuclides such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18. The basic facility consists of a medical cyclotron (10 MeV proton and 5 MeV deuteron), six lead-shielded hot cells with associated radiochemistry facilities, radiopharmacy and a whole body PET scanner. A strong radiolabelling development program, including the production of 15O-oxygen, 15O-carbon monoxide, 15O-carbon dioxide, 15O-water, 13N-ammonia, 18F-FDG, 18F-FMISO, 11C-SCH23390 and 11C-flumazenil has been pursued to support an ambitious clinical and research program in neurology, oncology, cardiology and psychiatry. Copyright (1999) Australasian Physical and Engineering Sciences in Medicine and the College of Biomedical Engineers

  11. Pulmonary studies using positron emission tomography

    International Nuclear Information System (INIS)

    The detailed investigation of regional differences in lung function at a local level began when suitable γ-ray emitting isotopes and focused external radiation detectors (especially the Anger γ-camera) became available. A major recent advance has been the development of positron emission tomography (PET), which provides a powerful combination of highly accurate tomographic reconstruction of radioisotope concentration with a potentially unlimited list of biological compounds to be labelled with the positron emitting isotopes of oxygen, carbon and fluorine. Early studies using PET focused on the inhalation of 11CO (or C15O) and 19Ne gases and the intravenous injection of 13N in saline and H215O for the measurement of relatively simple aspects of regional lung function, such as tissue, blood and gas volumes, blood flow, ventilation and ventilation/perfusion (V'A/Q'). More recent work has been directed towards the more challenging areas of regional endothelial permeability, carbohydrate utilization, enzyme and receptor binding assays, and in vivo pharmacokinetics. The short physical half-lives of the isotopes (17 s to 2 h) and the noninvasive nature of PET allows serial measurements to be made on patients (within the constraints of permitted radiation doses) to assess the effect of physiological and therapeutic interventions. (au) 80 refs

  12. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    International Nuclear Information System (INIS)

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy

  13. Time-course of serotonin transporter occupancy by single dose of three SSRIs in human brain: A positron emission tomography study with [(11)C]DASB.

    Science.gov (United States)

    Arakawa, Ryosuke; Tateno, Amane; Kim, WooChan; Sakayori, Takeshi; Ogawa, Kohei; Okubo, Yoshiro

    2016-05-30

    Sixteen healthy volunteers were enrolled and divided into four groups according to the single administration of 10mg or 20mg escitalopram, 50mg sertraline, or 20mg paroxetine. Four positron emission tomography scans with [(11)C]DASB were performed on each subject, the first prior to taking the drug, followed by the others at 4, 24, and 48h after. Serotonin transporter occupancies of the drugs at each time point were calculated. All drugs showed maximum occupancy at 4h after dosing and then decreasing occupancies with time. Escitalopram and sertraline showed high occupancies of 69.1-77.9% at 4h, remaining at 52.8-57.8% after 48h. On the other hand, paroxetine showed relatively low occupancy of 44.6%, then decreasing to 10.3% at 48h. Escitalopram (both 10mg and 20mg) and sertraline (50mg) showed high and sustained occupancy. Paroxetine (20mg) showed relatively low and rapidly decreasing occupancy, possibly due to the low plasma concentration by single dosing schedule. Applying the reported concentration of multiple dosing, 20mg paroxetine will induce over 80% occupancy. The present study suggested that these drugs and doses would be sufficient for the treatment of depression. PMID:27082864

  14. Motion correction in thoracic positron emission tomography

    CERN Document Server

    Gigengack, Fabian; Dawood, Mohammad; Schäfers, Klaus P

    2015-01-01

    Respiratory and cardiac motion leads to image degradation in Positron Emission Tomography (PET), which impairs quantification. In this book, the authors present approaches to motion estimation and motion correction in thoracic PET. The approaches for motion estimation are based on dual gating and mass-preserving image registration (VAMPIRE) and mass-preserving optical flow (MPOF). With mass-preservation, image intensity modulations caused by highly non-rigid cardiac motion are accounted for. Within the image registration framework different data terms, different variants of regularization and parametric and non-parametric motion models are examined. Within the optical flow framework, different data terms and further non-quadratic penalization are also discussed. The approaches for motion correction particularly focus on pipelines in dual gated PET. A quantitative evaluation of the proposed approaches is performed on software phantom data with accompanied ground-truth motion information. Further, clinical appl...

  15. Positron emission tomography in urological cancer

    International Nuclear Information System (INIS)

    In staging cancer of the urinary bladder, the kidneys and the prostate and of testicular cancer there is a need for detecting tumor involvement of the lymph nodes to avoid surgical exploration. Positron emission tomography (PET) using fluorodeoxyglucose (FDG) can detect tumorous lymph nodes (sensitivity: 70%, specificity: 85%) which is helpful for several patients. In carcinoma of the prostate, other radiotracers than FDG (e.g. C-11-choline) might be more sensitive to detect tumorous lymph nodes. Up to now no diagnostical benefit of PET in germ cell tumors could be demonstrated in the published small series. In principle FDG-PET is useful in diagnosis of recurrence. In germ cell cancer FDG-PET seems to identify effectively persistent vital tumor tissue after chemotherapy. A multicenter study was initiated to demonstrate the potential of FDG-PET in a sufficient number of patients with germ cell tumor. (orig.)

  16. Compact conscious animal positron emission tomography scanner

    Science.gov (United States)

    Schyler, David J.; O'Connor, Paul; Woody, Craig; Junnarkar, Sachin Shrirang; Radeka, Veljko; Vaska, Paul; Pratte, Jean-Francois; Volkow, Nora

    2006-10-24

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal for an event, generating an address signal representing a detecting channel, generating a detector channel signal including the time and address signals, and generating a composite signal including the channel signal and similarly generated signals. The composite signal includes events from detectors in a block and is serially output. An apparatus that serially transfers annihilation information from a block includes time signal generators for detectors in a block and an address and channel signal generator. The PET scanner includes a ring tomograph that mounts onto a portion of an animal, which includes opposing block pairs. Each of the blocks in a block pair includes a scintillator layer, detection array, front-end array, and a serial encoder. The serial encoder includes time signal generators and an address signal and channel signal generator.

  17. Positron emission tomography of the heart

    International Nuclear Information System (INIS)

    Positron emission computed tomography (PCT) represents an important new tool for the noninvasive evaluation and, more importantly, quantification of myocardial performance. Most currently available techniques permit assessment of only one aspect of cardiac function, i.e., myocardial perfusion by gamma scintillation camera imaging with Thallium-201 or left ventricular function by echocardiography or radionuclide angiocardiography. With PCT it may become possible to study all three major segments of myocardial performance, i.e., regional blood flow, mechanical function and, most importantly, myocardial metabolism. Each of these segments can either be evaluated separately or in combination. This report briefly describes the principles and technological advantages of the imaging device, reviews currently available radioactive tracers and how they can be employed for the assessment of flow, function and metabolism; and, lastly, discusses possible applications of PCT for the study of cardiac physiology or its potential role in the diagnosis of cardiac disease

  18. Positron emission tomography of the heart

    Energy Technology Data Exchange (ETDEWEB)

    Schelbert, H.R.; Phelps, M.E.; Kuhl, D.E.

    1979-01-01

    Positron emission computed tomography (PCT) represents an important new tool for the noninvasive evaluation and, more importantly, quantification of myocardial performance. Most currently available techniques permit assessment of only one aspect of cardiac function, i.e., myocardial perfusion by gamma scintillation camera imaging with Thallium-201 or left ventricular function by echocardiography or radionuclide angiocardiography. With PCT it may become possible to study all three major segments of myocardial performance, i.e., regional blood flow, mechanical function and, most importantly, myocardial metabolism. Each of these segments can either be evaluated separately or in combination. This report briefly describes the principles and technological advantages of the imaging device, reviews currently available radioactive tracers and how they can be employed for the assessment of flow, function and metabolism; and, lastly, discusses possible applications of PCT for the study of cardiac physiology or its potential role in the diagnosis of cardiac disease.

  19. Evaluation of the P-glycoprotein- and breast cancer resistance protein-mediated brain penetration of {sup 11}C-labeled topotecan using small-animal positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Tomoteru; Fujinaga, Masayuki; Kawamura, Kazunori; Hatori, Akiko; Yui, Joji [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Nengaki, Nobuki; Ogawa, Masanao; Yoshida, Yuichiro [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); SHI Accelerator Service, Ltd., Tokyo 141-8686 (Japan); Wakizaka, Hidekatsu [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Yanamoto, Kazuhiko [Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan); Fukumura, Toshimitsu [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Zhang Mingrong, E-mail: zhang@nirs.go.jp [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2011-07-15

    Introduction: Topotecan (TPT) is a camptothecin derivative and is an anticancer drug working as a topoisomerase-I-specific inhibitor. But TPT cannot penetrate through the blood-brain barrier. In this study, we synthesized a new positron emission tomography (PET) probe, [{sup 11}C]TPT, to evaluate the P-glycoprotein (Pgp)- and breast cancer resistance protein (BCRP)-mediated brain penetration of [{sup 11}C]TPT using small-animal PET. Methods: [{sup 11}C]TPT was synthesized by the reaction of a desmethyl precursor with [{sup 11}C]CH{sub 3}I. In vitro study using [{sup 11}C]TPT was carried out in MES-SA and doxorubicin-resistant MES-SA/Dx5 cells in the presence or absence of elacridar, a specific inhibitor for Pgp and BCRP. The biodistribution of [{sup 11}C]TPT was determined using small-animal PET and the dissection method in mice. Results: The transport of [{sup 11}C]TPT to the extracellular side was determined in MES-SA/Dx5 cells exhibiting the expressions of Pgp and BCRP at high levels. This transport was inhibited by coincubation with elacridar. In Mdr1a/b{sup -/-}Bcrp1{sup -/-} mice, PET results indicated that the brain uptake of [{sup 11}C]TPT was about two times higher than that in wild-type mice. Similarly, the brain penetration of [{sup 11}C]TPT in wild-type mice was increased by treatment with elacridar. The radioactivity in the brain of elacridar-treated mice was maintained at a certain level after the injection of [{sup 11}C]TPT, although the radioactivity in the blood decreased with time. Conclusions: We demonstrated the increase of brain penetration of [{sup 11}C]TPT by deficiency and inhibition of Pgp and BCRP functions using small-animal PET in mice.

  20. No difference in brain activation during cognitive performance between ecstasy (3,4-methylenedioxymethamphetamine) users and control subjects: a [H2(15)O]-positron emission tomography study.

    Science.gov (United States)

    Gamma, A; Buck, A; Berthold, T; Vollenweider, F X

    2001-02-01

    The long-term use of the serotonin-releaser and uptake-inhibitor 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") has been associated with memory impairments and increased liability to depressive mood and anxiety attacks. It is unclear, however, whether these psychologic deviations are reflected in alterations of the underlying neurophysiologic substrate. The authors compared mood and regional cerebral blood flow (rCBF) profiles between regular polytoxic Ecstasy users and Ecstasy-naive controls. Brain activity as indexed by rCBF was measured during cognitive activation by an attentional task using positron emission tomography and [H2(15)O]. Mood was assessed by means of the Hamilton Rating Scale for Depression (HAM-D) and the EWL Mood Rating Scale. Statistical parametric mapping revealed that brain activity did not differ between the two groups. Both groups also performed equally on the cognitive task requiring sustained attention. However, significantly higher levels of depressiveness as determined by the HAM-D and EWL scales were found in Ecstasy-using subjects. These data indicate that, despite differences in mood, polytoxic Ecstasy users do not differ from Ecstasy-naive controls in terms of local brain activity. Heightened depressiveness in the Ecstasy group was consistent with results from previous studies and could be related to serotonergic hypofunction resulting from repeated MDMA consumption. However, this study cannot exclude the possibility that the observed differences are preexisting rather than a result of Ecstasy use. PMID:11199950

  1. Synthesis of [11C-methyl]-(-)-OSU6162, its regional brain distribution and some pharmacological effects of (-)-OSU6162 on the dopaminergic system studied in the rhesus monkey by positron emission tomography

    International Nuclear Information System (INIS)

    The labelling of the presynaptic dopamine receptor antagonist (-)-OSU6162, ((S)-(-)-3-(3-(methylsulfonyl)phenyl)-1-propylpiperidine) was performed by an alkylation with [11C]methyl iodide of the thio anion (-)-OSU1281, followed by a selective oxidation to the corresponding methyl sulfone, [11C-methyl]-(-)-OSU6162. The total radiochemical yield calculated from the produced [11C]carbon dioxide to final product was about 25% and the time of synthesis was in the range of 40 min from end of bombardment. The synthesis of the precursor, (-)-OSU1281, was performed from (-)-3PPP in a three-step synthesis. The regional brain distribution of (-)-OSU6162 radiolabelled with 11C was studied in rhesus monkeys by means of positron emission tomography, PET. [11C-Methyl]-(-)-OSU6162 was rapidly and uniformly distributed to gray matters of the brain, and no decrease of radioactivity uptake in the brain was seen after pretreatment with 1 to 3 mg/kg/h of (-)-OSU6162. The effect of doses of 1 to 3 mg/kg/h of (-)-OSU6162 on the dopamine binding was studied by PET using [11C-methyl]raclopride. Radioactivity in the striatum was significantly and dose-dependently decreased by (-)-OSU6162 (r = 0.88), supporting competition with dopamine for selective binding to dopamine receptors

  2. Positron emission tomography and cerebral metabolism

    International Nuclear Information System (INIS)

    The association of new methods of labelling with short lived radioisotopes and of visualisation 'in vivo' of these labelled molecules by emission tomography, provide the possibility of studying brain metabolism at different levels. Two examples will illustrate the possibilities of this methodology. Cerebral metabolism of methionine-11C in phenylketonutic patients: The cerebral uptake of methionine was measured in 24 PKU children aged 1 to 40 months on a low protein diet. Ten of them were examined twice at intervals of several months. Stopping the diet for one week leads to an increase in blood phenylalanine and to a significant important decrease in brain uptake of labelled methionine. Futhermore, for children under treatment having a low phenylalanine blood concentration, brain uptake of methionine decreases with age between 1 and 40 months. These results suggest that the treatment of this disease should be started as soon as possible after birth. Cerebral metabolism of psychoactive drugs: The study of the brain distribution and kinetics of psychoactive drugs may help in understanding their mode of action. Chlorpromazine- 11C was administered i.v. to schyzophrenic patients not previously treated with neuroleptics. In all patients the brain uptake of the drug was high and rapid, and was localized mainly in the grey matter, probably in proportion to the blood flow. Non-specific binding of this drug to brain proteins prevented visualization of specific binding to dopaminergic or αnor-adrenergic receptors. Specific receptor binding of benzodiazepines was however visualized in the brain of baboons after injection of 11C-flunitrazepam (specific activity = 600 Ci/μmole) and subsequent displacement of this radioactive ligand by a pharmacological dose of Lorazepam

  3. Recent developments in positron emission tomography (PET) instrumentation

    International Nuclear Information System (INIS)

    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

  4. Simultaneous emission and transmission scanning in positron emission tomography

    International Nuclear Information System (INIS)

    Examination by PET (positron emission tomography) scanning, following the dosage of 2-deoxy-18F fluoro-D-glucose (FDG), is positively utilized for the diagnosis of cancers, rather than for the purpose of studies. This is because the examination by FDG-PET (PET scanning following the dosage of FDG) ensures higher efficiency in discrimination of cancers, than conventional CT and PET. The method of whole body scanning by PET scanning following the dosage of FDG is effectively utilized not only for discrimination cancers, but also for determining the degree of malignancy of tumors and evaluating the methods of treatment of cancers. In conventional methods for examining the degree of malignancy of tumors and evaluating the methods of cancer treatment, it is necessary to correct for the gamma-ray attenuation, which requires a longer time for examination, increasing the physical and psychological pains of the patients. We have installed the simultaneous emission and transmission scanning capability into the HEADTOME-V of the Shimadzu SET-2000W Series positron emission tomographic scanning instruments, to establish an instrument that permits FDG-PET whole body scanning in actual clinical fields, with minimized physical and psychological pains of patients concerned, yet ensuring an outstandingly high examination efficiency. This report also presents some data obtained by this newly developed instrument and those obtained in practical applications. (author)

  5. FDG positron emission computed tomography in a study of aphasia

    International Nuclear Information System (INIS)

    Positron emission computed tomography (PECT) using 18F-2-fluoro-2-deoxy-D-glucose (FDG) was used to investigate the correlations between clinical status, anatomy (as described by CT), and metabolism in five patients with stable aphasia resulting from ischemic cerebral infarction. Local cerebral metabolic activity was diminished in an area larger than the area of infarction demonstrated by CT. In one patient, FDG PECT revealed a metabolic lesion that probably caused the aphasic syndrome and was not apparent by CT. The data suggest that reliance on CT in delineating the extent of the brain lesion in aphasia or other neuropsychological defects can be misleading; FDG PECT may provide important additional information. Two patients with similar metabolic lesions had very different clinical syndromes, showing that even when currently available methods are combined, major gaps remain in clinicoanatomical correlations in aphasia

  6. Methodological review on functional neuroimaging using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Jeong [Yonsei University, College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    Advance of neuroimaging technique has greatly influenced recent brain research field. Among various neuroimaging modalities, positron emission tomography has played a key role in molecular neuroimaging though functional MRI has taken over its role in the cognitive neuroscience. As the analysis technique for PET data is more sophisticated, the complexity of the method is more increasing. Despite the wide usage of the neuroimaging techniques, the assumption and limitation of procedures have not often been dealt with for the clinician and researchers, which might be critical for reliability and interpretation of the results. In the current paper, steps of voxel-based statistical analysis of PET including preprocessing, intensity normalization, spatial normalization, and partial volume correction will be revisited in terms of the principles and limitations. Additionally, new image analysis techniques such as surface-based PET analysis, correlational analysis and multimodal imaging by combining PET and DTI, PET and TMS or EEG will also be discussed.

  7. Radiopharmaceuticals for positron emission tomography investigations of Alzheimer's disease

    International Nuclear Information System (INIS)

    Alzheimer's disease (AD) is a common degenerative neurological disease that is an increasing medical, economical, and social problem. There is evidence that a long ''asymptomatic'' phase of the disease exists where functional changes in the brain are present, but structural imaging for instance with magnetic resonance imaging remains normal. Positron emission tomography (PET) is one of the tools by which it is possible to explore changes in cerebral blood flow and metabolism and the functioning of different neurotransmitter systems. More recently, investigation of protein aggregations such as amyloid deposits or neurofibrillary tangles containing tau-protein has become possible. The purpose of this paper is to review the current knowledge on various 18F- and 11C-labelled PET tracers that could be used to study the pathophysiology of AD, to be used in the early or differential diagnosis or to be used in development of treatment and in monitoring of treatment effects. (orig.)

  8. Methodological review on functional neuroimaging using positron emission tomography

    International Nuclear Information System (INIS)

    Advance of neuroimaging technique has greatly influenced recent brain research field. Among various neuroimaging modalities, positron emission tomography has played a key role in molecular neuroimaging though functional MRI has taken over its role in the cognitive neuroscience. As the analysis technique for PET data is more sophisticated, the complexity of the method is more increasing. Despite the wide usage of the neuroimaging techniques, the assumption and limitation of procedures have not often been dealt with for the clinician and researchers, which might be critical for reliability and interpretation of the results. In the current paper, steps of voxel-based statistical analysis of PET including preprocessing, intensity normalization, spatial normalization, and partial volume correction will be revisited in terms of the principles and limitations. Additionally, new image analysis techniques such as surface-based PET analysis, correlational analysis and multimodal imaging by combining PET and DTI, PET and TMS or EEG will also be discussed

  9. Simulation of the annihilation emission of galactic positrons

    International Nuclear Information System (INIS)

    Positrons annihilate in the central region of our Galaxy. This has been known since the detection of a strong emission line centered on an energy of 511 keV in the direction of the Galactic center. This gamma-ray line is emitted during the annihilation of positrons with electrons from the interstellar medium. The spectrometer SPI, onboard the INTEGRAL observatory, performed spatial and spectral analyses of the positron annihilation emission. This thesis presents a study of the Galactic positron annihilation emission based on models of the different interactions undergone by positrons in the interstellar medium. The models are relied on our present knowledge of the properties of the interstellar medium in the Galactic bulge, where most of the positrons annihilate, and of the physics of positrons (production, propagation and annihilation processes). In order to obtain constraints on the positrons sources and physical characteristics of the annihilation medium, we compared the results of the models to measurements provided by the SPI spectrometer. (author)

  10. Amorphous silicon detectors in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Conti, M. (Istituto Nazionale di Fisica Nucleare, Pisa (Italy) Lawrence Berkeley Lab., CA (USA)); Perez-Mendez, V. (Lawrence Berkeley Lab., CA (USA))

    1989-12-01

    The physics of the detection process is studied and the performances of different Positron Emission Tomography (PET) system are evaluated by theoretical calculation and/or Monte Carlo Simulation (using the EGS code) in this paper, whose table of contents can be summarized as follows: a brief introduction to amorphous silicon detectors and some useful equation is presented; a Tantalum/Amorphous Silicon PET project is studied and the efficiency of the systems is studied by Monte Carlo Simulation; two similar CsI/Amorphous Silicon PET projects are presented and their efficiency and spatial resolution are studied by Monte Carlo Simulation, light yield and time characteristics of the scintillation light are discussed for different scintillators; some experimental result on light yield measurements are presented; a Xenon/Amorphous Silicon PET is presented, the physical mechanism of scintillation in Xenon is explained, a theoretical estimation of total light yield in Xenon and the resulting efficiency is discussed altogether with some consideration of the time resolution of the system; the amorphous silicon integrated electronics is presented, total noise and time resolution are evaluated in each of our applications; the merit parameters {epsilon}{sup 2}{tau}'s are evaluated and compared with other PET systems and conclusions are drawn; and a complete reference list for Xenon scintillation light physics and its applications is presented altogether with the listing of the developed simulation programs.

  11. Resistive plate chambers in positron emission tomography

    Science.gov (United States)

    Crespo, Paulo; Blanco, Alberto; Couceiro, Miguel; Ferreira, Nuno C.; Lopes, Luís; Martins, Paulo; Ferreira Marques, Rui; Fonte, Paulo

    2013-07-01

    Resistive plate chambers (RPC) were originally deployed for high energy physics. Realizing how their properties match the needs of nuclear medicine, a LIP team proposed applying RPCs to both preclinical and clinical positron emission tomography (RPC-PET). We show a large-area RPC-PET simulated scanner covering an axial length of 2.4m —slightly superior to the height of the human body— allowing for whole-body, single-bed RPC-PET acquisitions. Simulations following NEMA (National Electrical Manufacturers Association, USA) protocols yield a system sensitivity at least one order of magnitude larger than present-day, commercial PET systems. Reconstruction of whole-body simulated data is feasible by using a dedicated, direct time-of-flight-based algorithm implemented onto an ordered subsets estimation maximization parallelized strategy. Whole-body RPC-PET patient images following the injection of only 2mCi of 18-fluorodesoxyglucose (FDG) are expected to be ready 7 minutes after the 6 minutes necessary for data acquisition. This compares to the 10-20mCi FDG presently injected for a PET scan, and to the uncomfortable 20-30minutes necessary for its data acquisition. In the preclinical field, two fully instrumented detector heads have been assembled aiming at a four-head-based, small-animal RPC-PET system. Images of a disk-shaped and a needle-like 22Na source show unprecedented sub-millimeter spatial resolution.

  12. Utility of positron emission tomography in schwannomatosis.

    Science.gov (United States)

    Lieber, Bryan; Han, ByoungJun; Allen, Jeffrey; Fatterpekar, Girish; Agarwal, Nitin; Kazemi, Noojan; Zagzag, David

    2016-08-01

    Schwannomatosis is characterized by multiple non-intradermal schwannomas with patients often presenting with a painful mass in their extremities. In this syndrome malignant transformation of schwannomas is rare in spite of their large size at presentation. Non-invasive measures of assessing the biological behavior of plexiform neurofibromas in neurofibromatosis type 1 such as positron emission tomography (PET), CT scanning and MRI are well characterized but little information has been published on the use of PET imaging in schwannomatosis. We report a unique clinical presentation portraying the use of PET imaging in schwannomatosis. A 27-year-old woman presented with multiple, rapidly growing, large and painful schwannomas confirmed to be related to a constitutional mutation in the SMARCB1 complex. Whole body PET/MRI revealed numerous PET-avid tumors suggestive of malignant peripheral nerve sheath tumors. Surgery was performed on multiple tumors and none of them had histologic evidence of malignant transformation. Overall, PET imaging may not be a reliable predictor of malignant transformation in schwannomatosis, tempering enthusiasm for surgical interventions for tumors not producing significant clinical signs or symptoms. PMID:26960263

  13. Amorphous silicon detectors in positron emission tomography

    International Nuclear Information System (INIS)

    The physics of the detection process is studied and the performances of different Positron Emission Tomography (PET) system are evaluated by theoretical calculation and/or Monte Carlo Simulation (using the EGS code) in this paper, whose table of contents can be summarized as follows: a brief introduction to amorphous silicon detectors and some useful equation is presented; a Tantalum/Amorphous Silicon PET project is studied and the efficiency of the systems is studied by Monte Carlo Simulation; two similar CsI/Amorphous Silicon PET projects are presented and their efficiency and spatial resolution are studied by Monte Carlo Simulation, light yield and time characteristics of the scintillation light are discussed for different scintillators; some experimental result on light yield measurements are presented; a Xenon/Amorphous Silicon PET is presented, the physical mechanism of scintillation in Xenon is explained, a theoretical estimation of total light yield in Xenon and the resulting efficiency is discussed altogether with some consideration of the time resolution of the system; the amorphous silicon integrated electronics is presented, total noise and time resolution are evaluated in each of our applications; the merit parameters ε2τ's are evaluated and compared with other PET systems and conclusions are drawn; and a complete reference list for Xenon scintillation light physics and its applications is presented altogether with the listing of the developed simulation programs

  14. Myocardial energy metabolism by positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) permits quantitative measurement of myocardial blood flow and metabolism in vivo in the cardiovascular areas. F-18 fluorodeoxyglucose (FDG) and C-11 palmitate have been used for energy metabolism in the cardiac PET. In fasting condition, beta-oxydation of fatty acids is the major energy source in the normal myocardium, whereas glucose metabolism is enhanced in the ischemic myocardium. No metabolic substrate is used in the necrotic myocardium. Thus, quantitative measurement of substrate utilization enables differentiation of ischemic from normal or infarcted myocardium and precise assessment of tissue abnormalities in vivo. FDG is administrated in fasting condition in our institute in order to delineate ischemic myocardium as a hot spot with suppression of the FDG uptake in the normal myocardium. However, when compared to the postprandial condition, FDG uptake may be enhanced even in the infarcted tissue, and thus, may possibly overestimate the tissue viability. A certain quantification of FDG uptake may be warranted for an accurate evaluation of FDG uptake. We have been measured FDG uptake index as a fraction of injected dose (% dose/100g tissue). This index correlated well with myocardial metabolic rate of glucose by Phelps method in the fasting condition. Dynamic PET study after C-11 palmitate injection has been used for estimate of fatty acid utilization. The first component of the washout from the myocardium is considered as rate of beta-oxydation. However, the washout of this tracer seems to be strikingly different between the fasting and postprandial conditions. (J.P.N.)

  15. Patient radiation protection in positron emission tomography

    International Nuclear Information System (INIS)

    Patient radiation protection in Positron Emission Tomography (PET) is closely related to the correct execution of studies: proper scanner performance, and optimization of both image quality and patient dose. We describe the quality control tests considered as essential: scanner stability, spatial resolution, sensitivity and tomographic uniformity. Knowledge of the dose received by the critical organ and the effective dose for each radiopharmaceutical allows the establishment of strategies for dose optimization. Although a great variety of PET tracers exist, we review the dose produced by F-FDG, the most widely used tracer, and those used in our PET Center O-Water, N-Ammonia, C-Methionine, C-Choline, F-Choline, F-Dopa, and F-FHBG. Reduction of administered activity to the patient is the direct way to reduce the dose. Thus, PET acquisition in the 3D mode, with higher sensitivity, is a determining factor. In order to reduce the dose to different organs, efforts should be directed to the critical organs, mainly the urinary bladder wall. Finally, correct patient preparation improves, PET image quality, due to an optimum tracer uptake, which optimizes the dose to different organs. (Author) 25 refs

  16. Monoamine re-uptake sites in the human brain evaluated in vivo by means of 11C-nomifensine and positron emission tomography: the effects of age and Parkinson's disease

    International Nuclear Information System (INIS)

    Six patients with Parkinson's disease, selected to cover a range of clinical features, and 7 healthy volunteers aged 24-81 years, were examined by positron emission tomography after i.v. injection of racemic 11C-nomifensine, a catecholamine re-uptake blocking drug. After injection the radiotracer, radioactivity was rapidly distributed to the brain. The highest accumulation of radioactivity was found in areas rich in dopamineric and noradrenergic innervation, such as the striatum and the thalamus. In regions with negible dopaminergic and noradrenergic innervation, such as the cerebellum, radioactivity was lower and evenly distributed. In all investigated brain regions a marked age-related decline in 11C-nomifensinederived radioactivity relative to the cerebellum was observed in the group of healthy volunteers. Parkinsonian patients did not show such a decline with age. In the group of parkinsonian patients with mainly unilateral involvement, the contralateral putamen exhibited the most pronounced decrease. Only the 3 parkinsonian patients aged 63 and younger showed markedly lower 11C-nomifensine binding in striatal areas than age-matched healthy volunteers. 11C-nomifensine seems to be a valuable tool for investigating noradrenergic and dopaminergic re-uptake sites in vivo. Further achievements will most likely be made when the active enantioimer becomes available. (author)

  17. Shielding design for positron emission tomography facility

    International Nuclear Information System (INIS)

    With the recent advent of readily available tracer isotopes, there has been marked increase in the number of hospital-based and free-standing positron emission tomography (PET) clinics. PET facilities employ relatively large activities of high-energy photon emitting isotopes, which can be dangerous to the health of humans and animals. This coupled with the current dose limits for radiation worker and members of the public can result in shielding requirements. This research contributes to the calculation of the appropriate shielding to keep the level of radiation within an acceptable recommended limit. Two different methods were used including measurements made at selected points of an operating PET facility and computer simulations by using Monte Carlo Transport Code. The measurements mainly concerned the radiation exposure at different points around facility using the survey meter detectors and Thermoluminescent Dosimeters (TLD). Then the set of manual calculation procedures were used to estimate the shielding requirements for a newly built PEF facility. The results from the measurement and the computer simulation were compared to the results obtained from the set manual calculation procedure. In general, the estimated weekly dose at the points of interest is lower than the regulatory limits for the little company of Mary Hospital. Furthermore, the density and the HVL for normal strength concrete and clay bricks are almost similar. In conclusion, PET facilities present somewhat different design requirements and are more likely to require additional radiation shielding. Therefore, existing shields at the little Company of Mary Hospital are in general found to be adequate and satisfactory and additional shielding was found necessary at the new PET facility in the department of Nuclear Medicine of the Dr. George Mukhari Hospital. By use of appropriate design, by implying specific shielding requirements and by maintaining good operating practices, radiation doses to

  18. Positron Emission Mammography with Multiple Angle Acquisition

    International Nuclear Information System (INIS)

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FDG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three- dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned

  19. Positron emission tomography/computed tomography.

    Science.gov (United States)

    Townsend, David W

    2008-05-01

    Accurate anatomical localization of functional abnormalities obtained with the use of positron emission tomography (PET) is known to be problematic. Although tracers such as (18)F-fluorodeoxyglucose ((18)F-FDG) visualize certain normal anatomical structures, the spatial resolution is generally inadequate for accurate anatomic localization of pathology. Combining PET with a high-resolution anatomical imaging modality such as computed tomography (CT) can resolve the localization issue as long as the images from the two modalities are accurately coregistered. However, software-based registration techniques have difficulty accounting for differences in patient positioning and involuntary movement of internal organs, often necessitating labor-intensive nonlinear mapping that may not converge to a satisfactory result. Acquiring both CT and PET images in the same scanner obviates the need for software registration and routinely provides accurately aligned images of anatomy and function in a single scan. A CT scanner positioned in line with a PET scanner and with a common patient couch and operating console has provided a practical solution to anatomical and functional image registration. Axial translation of the couch between the 2 modalities enables both CT and PET data to be acquired during a single imaging session. In addition, the CT images can be used to generate essentially noiseless attenuation correction factors for the PET emission data. By minimizing patient movement between the CT and PET scans and accounting for the axial separation of the two modalities, accurately registered anatomical and functional images can be obtained. Since the introduction of the first PET/CT prototype more than 6 years ago, numerous patients with cancer have been scanned on commercial PET/CT devices worldwide. The commercial designs feature multidetector spiral CT and high-performance PET components. Experience has demonstrated an increased level of accuracy and confidence in the

  20. Inhibition of [(11)C]mirtazapine binding by alpha(2)-adrenoceptor antagonists studied by positron emission tomography in living porcine brain

    DEFF Research Database (Denmark)

    Smith, Donald F.; Dyve, Suzan; Minuzzi, Luciano;

    2006-01-01

    We have developed [(11)C]mirtazapine as a ligand for PET studies of antidepressant binding in living brain. However, previous studies have determined neither optimal methods for quantification of [(11)C]mirtazapine binding nor the pharmacological identity of this binding. To obtain that informati...... brain. Synapse 59:463-471, 2006. (c) 2006 Wiley-Liss, Inc....

  1. Complementary information from magnetic resonance imaging and {sup 18}F-fluoromisonidazole positron emission tomography in the assessment of the response to an antiangiogenic treatment in a rat brain tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Valable, Samuel, E-mail: valable@cyceron.fr [CERVOxy group, UMR 6232 CI-NAPS. CNRS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CEA. GIP CYCERON, Bd Henri Becquerel, BP5229, 14074 CAEN cedex (France); Petit, Edwige; Roussel, Simon; Marteau, Lena; Toutain, Jerome; Divoux, Didier [CERVOxy group, UMR 6232 CI-NAPS. CNRS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CEA. GIP CYCERON, Bd Henri Becquerel, BP5229, 14074 CAEN cedex (France); Sobrio, Franck; Delamare, Jerome; Barre, Louisa [GDM-TEP DSV/I2BM group, UMR 6232 CI-NAPS. CNRS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CEA. GIP CYCERON, Bd Henri Becquerel, BP5229, 14074 CAEN cedex (France); Bernaudin, Myriam [CERVOxy group, UMR 6232 CI-NAPS. CNRS, Universite de Caen Basse-Normandie, Universite Paris-Descartes, CEA. GIP CYCERON, Bd Henri Becquerel, BP5229, 14074 CAEN cedex (France)

    2011-08-15

    Introduction: No direct proof has been brought to light in a link between hypoxic changes in glioma models and the effects of antiangiogenic treatments. Here, we assessed the sensitivity of the detection of hypoxia through the use of {sup 18}F-fluoromisonidazole positron emission tomography ([{sup 18}F]-FMISO PET) in response to the evolution of the tumor and its vasculature. Methods: Orthotopic glioma tumors were induced in rats after implantation of C6 or 9L cells. Sunitinib was administered from day (D) 17 to D24. At D17 and D24, multiparametric magnetic resonance imaging was performed to characterize tumor growth and vasculature. Hypoxia was assessed by [{sup 18}F]-FMISO PET. Results: We showed that brain hypoxic volumes are related to glioma volume and its vasculature and that an antiangiogenic treatment, leading to an increase in cerebral blood volume and a decrease in vessel permeability, is accompanied by a decrease in the degree of hypoxia. Conclusions: We propose that [{sup 18}F]-FMISO PET and multiparametric magnetic resonance imaging are pertinent complementary tools in the evaluation of the effects of an antiangiogenic treatment in glioma.

  2. Complementary information from magnetic resonance imaging and 18F-fluoromisonidazole positron emission tomography in the assessment of the response to an antiangiogenic treatment in a rat brain tumor model

    International Nuclear Information System (INIS)

    Introduction: No direct proof has been brought to light in a link between hypoxic changes in glioma models and the effects of antiangiogenic treatments. Here, we assessed the sensitivity of the detection of hypoxia through the use of 18F-fluoromisonidazole positron emission tomography ([18F]-FMISO PET) in response to the evolution of the tumor and its vasculature. Methods: Orthotopic glioma tumors were induced in rats after implantation of C6 or 9L cells. Sunitinib was administered from day (D) 17 to D24. At D17 and D24, multiparametric magnetic resonance imaging was performed to characterize tumor growth and vasculature. Hypoxia was assessed by [18F]-FMISO PET. Results: We showed that brain hypoxic volumes are related to glioma volume and its vasculature and that an antiangiogenic treatment, leading to an increase in cerebral blood volume and a decrease in vessel permeability, is accompanied by a decrease in the degree of hypoxia. Conclusions: We propose that [18F]-FMISO PET and multiparametric magnetic resonance imaging are pertinent complementary tools in the evaluation of the effects of an antiangiogenic treatment in glioma.

  3. The Buecherer-Strecker synthesis of D- and L-(1-11C)tyrosine and the in vivo study of 0100L-(1-11C)tyrosine in human brain using positron emission tomography

    International Nuclear Information System (INIS)

    The synthesis of D- and L-(1-11C)tyrosine, starting with 11C-cyanide, is reported. DL-(1-11C)tyrosine was prepared by the Buecherer-Strecker reaction, from carrier added 11C-cyanide with an incorporation of 80% in 20 min. The isolation of the pure D- and L-amino acid isomers from the enantiomeric mixture was accomplished within 15 min by preparative HPLC using a chiral stationary phase and a phosphate buffer as the mobile phase. Typically, the total synthesis time was 50 min (including purification) from end of trapping of 11C-cyanide, with a radiochemical yield of D- and L-amino acid of 40%-60%. The D- and L-(1-11C)tyrosine were both obtained optically pure, with a carrier added specific activity of 0.3-0.5 Ci/mmol and a radiochemical purity better than 99%. The 11C labelled L-tyrosine was used in an in vivo study in the human brain using positron emission tomography (PET). (orig.)

  4. The introduction of positron emission tomography in Australia

    International Nuclear Information System (INIS)

    Positron Emission Tomography (PET) is a relatively new medical imaging modality based on images of the distribution of positron emitting radioisotopes in the human body. A PET scan can non-invasively provide quantitative information on the in vivo function performance of an organ, part thereof, or a bodily process. Two PET centres currently being established in Melbourne and in Sydney are introduced. 18 refs., 1 tab., 5 figs

  5. Sex Differences of Brain Serotonin Synthesis in Patients with Irritable Bowel Syndrome Using α-[11C]methyl-L-tryptophan, Positron Emission Tomography and Statistical Parametric Mapping

    OpenAIRE

    NAKAI, Akio; Kumakura, Yoshikata; Boivin, Michel; Rosa, Pedro; Diksic, Mirko; D’Souza, Doreen; Kersey, Kathryn

    2003-01-01

    BACKGROUND: Irritable bowel syndrome (IBS) is the most common functional bowel disorder and has a strong predominance in women. Recent data suggest that the brain may play an important role in the pathophysiology of IBS in the brain-gut axis. It is strongly suspected that serotonin (5-HT), a neurotransmitter found in the brain and gut, may be related to the pathophysiology of IBS. It is reported that a 5-HT3 antagonist is effective only in female patients with diarrhea-predominant IBS.OBJECTI...

  6. Positron emission tomography and migraine. Tomographie par emission de positons et migraine

    Energy Technology Data Exchange (ETDEWEB)

    Chabriat, H. (CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot)

    1992-04-01

    Positron emission tomography (PET) is a brain imaging technique that allows in vivo studies of numerous physiological parameters. There have been few PET studies in migraine patients. Cerebral blood flow changes with no variations in brain oxygen consumption have been reported in patients with prolonged neurologic manifestations during migraine attacks. Parenteral administration of reserpine during migraine headache has been followed by a fall in the overall cerebral uptake of glucose. The small sample sizes and a number of methodologic problems complicate the interpretation of these results. Recent technical advances and the development of new PET tracers can be expected to provide further insight into the pathophysiology of migraine. Today cerebral cortex 5 HT{sub 2} serotonin receptors can be studied in migraine patients with PET.

  7. In vivo determination of the kinetic parameters of glucose transport in the human brain using 11C-methyl-D-glucose (CMG) and dynamic positron emission tomography (dPET)

    International Nuclear Information System (INIS)

    A method was developed to measure simultaneously (1) the rate constants for glucose influx and glucose efflux, and (2) the Michaelis-Menten constant (Ksub(M)) and maximal velocity (νsub(max)) for glucose transport across the blood-brain barrier (BBB) in any selected brain area. Moreover, on the basis of a mathematical model, the local perfusion rate (LPR) and local unidirectional glucose transport rate (LUGTR) are calculated in terms of parameters of the time-activity curves registered over different brain regions; 11C-methyl-D-glucose (CMG) is used as an indicator. The transaxial distribution of activity in the organism is registered using dynamic positron-emission tomography (dPET). The method was used in 4 normal subjects and 50 patients with ischemic brain disease. In normals, the rate constant for CMG efflux was found to be 0.25+-0.04 min-1 in the cortex and 0.12+-0.02 min-1 in white matter. In the cortex, the Ksub(M) was found to be 6.42 μmol/g and the Vsub(max) was 2.46 μmol/g per minute. The LUGTR ranged from 0.43 to 0.6 μmol/g per minute in white matter. The LPR was calculated to be 0.80-0.98 ml/g per minute for the cortex and 0.2-0.4 ml/g per minute for white matter. In patients with stroke, the ischemic defects appeared to be larger in CMG scans than in computed tomography (CT) scans. Prolonged reversible ischemic neurological deficit was associated with a significant fall in the LUGTR but not change in the LPR in the corresponding cerebral cortex. Normal LUGTR and significantly decreased LPR were registered in a patient with progressive occulsion of the middle cerebral artery. In a patient with transient ischemic attacks, a slightly reduced LPR and a disproportionally reduced LUGTR were observed before operation. After extra- and intracranial bypass surgery, the LPR became normal, whereas the LUGTR increased but did not achieve normal values. (orig.)

  8. Perspectives for positron emission tomography with RPCs

    International Nuclear Information System (INIS)

    Full text: The basis of PET (Positron Emission Tomography) consists on the administration of a radioactive isotope attached to a tracer that permits to reveal its molecular pathways in a human body. A 3-D Complete-Body-Scan is desired in order to minimize the radiation dose to the patient and to increase the sensitivity of the axial field of view (FOV). A major candidate for gamma pair detection in 3-D Complete- Body-Scan are the RPCs (Resistive Plate Counters). They consist in a longitudinal microstrip grid 1.5 mm thick, spaced at 1 mm. The grid is placed between a large electric resistive glass anode and an aluminum cathode. The gap, around 300 m, is filled with a special gas and is polarized at around 6 kV. Every microstrip is equipped with high-speed preamplifier at both ends, allowing time of flight measurements. The RPC are solely tracking devices enjoying a large density of detection units. By construction they are able to provide an extremely large transverse resolution, the collecting leads being some 2.5 mm spaced. The longitudinal resolution is less sensitive, depending on the speed of the time of flight electronics. At this moment we estimate a 20 mm resolution. The RPCs present two main features: large longitudinal dimension and large transversal resolution which made them ideal for complete-body-scan devices. These peculiar features are the keys of a RPCs tomographic device. The evaluation of RPCs for 3-D Complete-Body-Scan followed two steps, the simulation of data acquisition and the image reconstruction. We choose the detecting base unit like a RPC, 2 meters long and 0.5 meters wide. According to previous assumptions this plate has a transverse resolution of 256 detection units and a longitudinal resolution of 100. (The transversal step is around 2 mm and the longitudinal step about 20 mm). Several base units are assembled to form different detecting structures. Two plates form an open detection structure like a sandwich. Four and six plates are

  9. Reconstruction Algorithms for Positron Emission Tomography and Single Photon Emission Computed Tomography and their Numerical Implementation

    CERN Document Server

    Fokas, A S; Marinakis, V

    2004-01-01

    The modern imaging techniques of Positron Emission Tomography and of Single Photon Emission Computed Tomography are not only two of the most important tools for studying the functional characteristics of the brain, but they now also play a vital role in several areas of clinical medicine, including neurology, oncology and cardiology. The basic mathematical problems associated with these techniques are the construction of the inverse of the Radon transform and of the inverse of the so called attenuated Radon transform respectively. We first show that, by employing mathematical techniques developed in the theory of nonlinear integrable equations, it is possible to obtain analytic formulas for these two inverse transforms. We then present algorithms for the numerical implementation of these analytic formulas, based on approximating the given data in terms of cubic splines. Several numerical tests are presented which suggest that our algorithms are capable of producing accurate reconstruction for realistic phanto...

  10. Positron emission tomography in colorectal cancer;Tomografia por emissao de positron no cancer colorretal

    Energy Technology Data Exchange (ETDEWEB)

    Gabure, Jose Luiz de Carvalho; Bacega, Marcelle Francine [Universidade Cidade de Sao Paulo (UNICID), Sao Paulo, SP (Brazil); Racy, Douglas Jorge; Lima, Rodrigo Vaz de; Rigo, Leticia, E-mail: letirigo3@hotmail.co [Med Imagem Diagnosticos por Imagem, Sao Paulo, SP (Brazil)

    2009-12-15

    After an introduction on the physical and biological basics of positron emission tomography, this paper reviews the current status of PET imaging using the glucose analogue FDG in colorectal cancer. The use of PET-FDG is reviewed for detection, initial staging, therapy monitoring and staging of disease relapse. (author)

  11. Physical and technical basis of positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Positron emission tomography utilizes the annihilation of positrons, generating pairs of gamma quanta which are emitted in opposing directions. 'Electronic collimation' is performed by coincident detection of both quanta. Thus, there is no need for mechanical collimators and no limiting connection between sensitivity and spatial resolution. Transversal tomograms are reconstructed from the projection data by means of highly sophisticated data processing. The half life of the most positron emitters used in medical applications is short and of the order of some minutes. Therefore, many positron emitters have to be produced on-side by means of a cyclotron. PET is superior to SPECT with respect to physical and technical aspects, but the high costs of PET limit its wide-spread use up to now. (orig.)

  12. Improved sampling in positron emission tomography

    International Nuclear Information System (INIS)

    The biomedical research performed with the Donner 280-Crystal Positron Tomograph requires data acquisition times of five seconds or less and the ability to gate the data acquisition for periods during the cardiac cycle when the heart is nearly at rest. These requirements pose severe restrictions on the amount of detector movement and have motivated the search for a scheme that improves lateral sampling with a minimum number of detector positions. A new approach, developed by our group, involves only two positions of the detector assembly and increases lateral sampling uniformly by a factor of two. This new approach is referred as clamshell sampling. To test clamshell sampling we performed Monte Carlo computer simulations of data acquisition with the new geometry. Hot spots of varying sizes and separation comprise the model used in a geometry scaled to test imaging the human head with the Donner 280-Crystal Positron Tomograph

  13. Liquid Xenon Detectors for Positron Emission Tomography

    OpenAIRE

    Miceli, A.; Amaudruz, P.; Benard, F.; Bryman, D. A.; Kurchaninov, L.; Martin, J. P.; Muennich, A.; Retiere, F.; Ruth, T J.; Sossi, V.; A.J. Stoessl

    2011-01-01

    PET is a functional imaging technique based on detection of annihilation photons following beta decay producing positrons. In this paper, we present the concept of a new PET system for preclinical applications consisting of a ring of twelve time projection chambers filled with liquid xenon viewed by avalanche photodiodes. Simultaneous measurement of ionization charge and scintillation light leads to a significant improvement to spatial resolution, image quality, and sensitivity. Simulated per...

  14. Positron Emission Tomography Using Fluorine F 18 EF5 to Find Oxygen in Tumor Cells of Patients Who Are Undergoing Surgery or Biopsy for Newly Diagnosed Brain Tumors

    Science.gov (United States)

    2013-01-15

    Adult Anaplastic Astrocytoma; Adult Anaplastic Ependymoma; Adult Anaplastic Oligodendroglioma; Adult Brain Stem Glioma; Adult Central Nervous System Germ Cell Tumor; Adult Choroid Plexus Tumor; Adult Craniopharyngioma; Adult Diffuse Astrocytoma; Adult Ependymoblastoma; Adult Ependymoma; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Adult Grade I Meningioma; Adult Grade II Meningioma; Adult Grade III Meningioma; Adult Medulloblastoma; Adult Meningeal Hemangiopericytoma; Adult Mixed Glioma; Adult Myxopapillary Ependymoma; Adult Oligodendroglioma; Adult Pilocytic Astrocytoma; Adult Pineoblastoma; Adult Pineocytoma; Adult Subependymoma; Adult Supratentorial Primitive Neuroectodermal Tumor (PNET); Meningeal Melanocytoma

  15. Age, sex and NK1 receptors in the human brain -- a positron emission tomography study with [¹¹C]GR205171.

    Science.gov (United States)

    Engman, Jonas; Åhs, Fredrik; Furmark, Tomas; Linnman, Clas; Pissiota, Anna; Appel, Lieuwe; Frans, Örjan; Långström, Bengt; Fredrikson, Mats

    2012-08-01

    The substance P/neurokinin 1 (SP/NK1) system has been implicated in the processing of negative affect. Its role seems complex and findings from animal studies have not been easily translated to humans. Brain imaging studies on NK1 receptor distribution in humans have revealed an abundance of receptors in cortical, striatal and subcortical areas, including the amygdala. A reduction in NK1 receptors with increasing age has been reported in frontal, temporal, and parietal cortices, as well as in hippocampal areas. Also, a previous study suggests sex differences in cortical and subcortical areas, with women displaying fewer NK1 receptors. The present PET study explored NK1 receptor availability in men (n=9) and women (n=9) matched for age varying between 20 and 50years using the highly specific NK1 receptor antagonist [¹¹C]GR205171 and a reference tissue model with cerebellum as the reference region. Age by sex interactions in the amygdala and the temporal cortex reflected a lower NK1 receptor availability with increasing age in men, but not in women. A general age-related decline in NK1 receptor availability was evident in the frontal, temporal, and occipital cortices, as well as in the brainstem, caudate nucleus, and thalamus. Women had lower NK1 receptor availability in the thalamus. The observed pattern of NK1 receptor distribution in the brain might have functional significance for brain-related disorders showing age- and sex-related differences in prevalence. PMID:22225860

  16. The electronics system for the LBNL positron emission tomography (PEM) camera

    OpenAIRE

    Moses, W. W.; Young, J.W.; Baker, K.; Jones, W; Lenox, M.; Ho, M. H.; Weng, M.

    2000-01-01

    We describe the electronics for a high performance Positron Emission Mammography (PEM) camera. It is based on the electronics for a human brain PET camera (the Siemens/CTI HRRT), modified to use a detector module that incorporates a photodiode (PD) array. An ASIC services the PD array, amplifying its signal and identifying the crystal of interaction. Another ASIC services the photomultiplier tube (PMT), measuring its output and providing a timing signal. Field programmable gate arrays (...

  17. Gliomatosis cerebri mimicking encephalitis evaluated using fluorine-18 fluorodeoxyglucose: Positron emission tomography/computed tomography

    International Nuclear Information System (INIS)

    Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis

  18. Utilisation of spatial and temporal correlations in positron emission tomography

    International Nuclear Information System (INIS)

    In this thesis we propose, implement, and evaluate algorithms improving spatial resolution in reconstructed images and reducing data noise in positron emission tomography imaging. These algorithms have been developed for a high resolution tomograph (HRRT) and applied to brain imaging, but can be used for other tomographs or studies. We first developed an iterative reconstruction algorithm including a stationary and isotropic model of resolution in image space, experimentally measured. We evaluated the impact of such a model of resolution in Monte-Carlo simulations, physical phantom experiments and in two clinical studies by comparing our algorithm with a reference reconstruction algorithm. This study suggests that biases due to partial volume effects are reduced, in particular in the clinical studies. Better spatial and temporal correlations are also found at the voxel level. However, other methods should be developed to further reduce data noise. We then proposed a maximum a posteriori de-noising algorithm that can be used for dynamic data to de-noise temporally raw data (sino-grams) or reconstructed images. The a priori modeled the coefficients in a wavelet basis of all the signals without noise (in an image or sinogram). We compared this technique with a reference de-noising method on replicated simulations. This illustrates the potential benefits of our approach of sinogram de-noising. (author)

  19. Biological imaging in radiation therapy: role of positron emission tomography

    International Nuclear Information System (INIS)

    In radiation therapy (RT), staging, treatment planning, monitoring and evaluation of response are traditionally based on computed tomography (CT) and magnetic resonance imaging (MRI). These radiological investigations have the significant advantage to show the anatomy with a high resolution, being also called anatomical imaging. In recent years, so called biological imaging methods which visualize metabolic pathways have been developed. These methods offer complementary imaging of various aspects of tumour biology. To date, the most prominent biological imaging system in use is positron emission tomography (PET), whose diagnostic properties have clinically been evaluated for years. The aim of this review is to discuss the valences and implications of PET in RT. We will focus our evaluation on the following topics: the role of biological imaging for tumour tissue detection/delineation of the gross tumour volume (GTV) and for the visualization of heterogeneous tumour biology. We will discuss the role of fluorodeoxyglucose-PET in lung and head and neck cancer and the impact of amino acids (AA)-PET in target volume delineation of brain gliomas. Furthermore, we summarize the data of the literature about tumour hypoxia and proliferation visualized by PET. We conclude that, regarding treatment planning in radiotherapy, PET offers advantages in terms of tumour delineation and the description of biological processes. However, to define the real impact of biological imaging on clinical outcome after radiotherapy, further experimental, clinical and cost/benefit analyses are required. (topical review)

  20. Measurement of regional cerebral blood flow by positron emission tomography

    International Nuclear Information System (INIS)

    The principal advantage of positron emission tomography over other methods for measuring cerebral blood flow stems from the accurate, quantitative three-dimensional measurements of regional brain radioactivity that are possible with this technique. As a result, accurate quantitative measurements of regional cerebral blood flow can be obtained for both superficial and deep cerebral structures. The value of PET for investigating central nervous system physiology and pathology extends far beyond this, however. Through the use of different radiotracers and appropriate mathematical models, PET can be applied to the measurement of a wide variety of physiologic variables. Measurements of rCBF tell only part of the story. Experience with PET and with a variety of other techniques has taught us that rCBF is at times a poor indicator of the metabolic, functional, and biochemical status of cerebral tissue. It is only by understanding the interaction of all of these factors that our understanding of neurologic disease can advance. It is in the investigation of these complex relationships that the real value of PET resides

  1. 64 Cu-pyruvaldehide-bis-(N4 methyl-thio semi-carbazone) - Cu-PTSM as brain tracer for positron emission tomography

    International Nuclear Information System (INIS)

    Synthesis of Pyruvaldehide-bis-(N4-methyl-thio semicarbazone) PTSM used for medical investigation and diagnosis has been carried out in our Radiopharmaceutical Division in Centro Atomico Ezeiza. PTSM has been obtained introducing modifications to a previous synthesis published by H.G. Petering TLC, HPLC and IR, UV spectrum controls have been performed. Cu-64 can be obtained by the Cu-63 (n, γ) and Zn-64 (n,p) reactions. This last reaction has been chosen for the production in the RA-3 reactor since it leads to Cu-64 of high specific activity. Two different assays have been performed to obtain the chelate PTSM-Cu-64. The first one has beer carried out by buffering the Cu-64 solution to pH 3-4; adding the PTSM solution in ethanol. The second assay has been carried out by buffering the Cu-64 solution with sodium acetate 3 M and adding 100 μl of PTSM solution in ethanol. The chelate thus obtained is purified in Sepak C-18. Radiochemical purity has been tested by thin layer chromatography. Biodistribution studies have been carried on NIH mice and Wistar rats showing a brain uptake of 4%, 30 minutes after injection. Thus, FTMS-Cu-64 proves to be a good brain diagnosis agent. (author). 7 refs., 3 figs

  2. Liquid Xenon Detectors for Positron Emission Tomography

    International Nuclear Information System (INIS)

    PET is a functional imaging technique based on detection of annihilation photons following beta decay producing positrons. In this paper, we present the concept of a new PET system for preclinical applications consisting of a ring of twelve time projection chambers filled with liquid xenon viewed by avalanche photodiodes. Simultaneous measurement of ionization charge and scintillation light leads to a significant improvement to spatial resolution, image quality, and sensitivity. Simulated performance shows that an energy resolution of < 10% (FWHM) and a sensitivity of 15% are achievable. First tests with a prototype TPC indicate position resolution < 1 mm (FWHM).

  3. Liquid Xenon Detectors for Positron Emission Tomography

    CERN Document Server

    Miceli, A; Benard, F; Bryman, D A; Kurchaninov, L; Martin, J P; Muennich, A; Retiere, F; Ruth, T J; Sossi, V; Stoessl, A J

    2011-01-01

    PET is a functional imaging technique based on detection of annihilation photons following beta decay producing positrons. In this paper, we present the concept of a new PET system for preclinical applications consisting of a ring of twelve time projection chambers filled with liquid xenon viewed by avalanche photodiodes. Simultaneous measurement of ionization charge and scintillation light leads to a significant improvement to spatial resolution, image quality, and sensitivity. Simulated performance shows that an energy resolution of <10% (FWHM) and a sensitivity of 15% are achievable. First tests with a prototype TPC indicate position resolution <1 mm (FWHM).

  4. Positron emission tomography experience with 2-[¹⁸F]fluoro-3-(2(S)-azetidinylmethoxy)pyridine (2-[¹⁸F]FA) in the living human brain of smokers with paranoid schizophrenia.

    Science.gov (United States)

    Brašić, James Robert; Cascella, Nicola; Kumar, Anil; Zhou, Yun; Hilton, John; Raymont, Vanessa; Crabb, Andrew; Guevara, Maria Rita; Horti, Andrew G; Wong, Dean Foster

    2012-04-01

    Utilizing postmortem data (Breese et al. [2000] Neuropsychopharmacology 23:351-364), we hypothesized that the densities of high-affinity neuronal α4β2 nicotinic acetylcholine receptors (nAChRs) in the brain exist in a continuum from highest to lowest as follows: smokers without schizophrenia > smokers with schizophrenia > nonsmokers without schizophrenia > nonsmokers with schizophrenia. Application of the Kruskal-Wallis Test (Statacorp, 2003) to the postmortem data (Breese et al. [2000] Neuropsychopharmacology 23:351-364) confirmed the hypothesized order in the cortex and the hippocampus and attained significance in the caudate and the thalamus. Positron emission tomography (PET) was performed for 60 min at 6 h after the intravenous administration of 444 megabequerels [MBq] (12 mCi) 2-[¹⁸F]fluoro-3-(2(S)-azetidinylmethoxy)pyridine (2-[¹⁸F]FA), a radiotracer for high-affinity neuronal α4β2 nAChRs, as a bolus plus continuous infusion to 10 adults (seven men and three women) (six smokers including five with paranoid schizophrenia and four nonsmokers) ranging in age from 22 to 56 years (mean 40.1, standard deviation 13.6). The thalamic nondisplaceable binding potential (BP(ND) ) was 1.32 ± 0.19 (mean ± standard deviation) for healthy control nonsmokers; 0.50 ± 0.19 for smokers with paranoid schizophrenia; and 0.51 for the single smoker without paranoid schizophrenia. The thalamic BP(ND) s of nonsmokers were significantly higher than those of smokers who smoked cigarettes a few hours before the scans (P = 0.0105) (StataCorp, 2003), which was likely due to occupancy of nAChRs by inhaled nicotine in smokers. Further research is needed to rule out the effects of confounding variables. PMID:22169936

  5. Physiopathology of ischemic strokes: the input of positron emission tomography

    International Nuclear Information System (INIS)

    The tomography by positrons emissions has brought essential physiological and pathological knowledge relative to cerebral vascular accidents in the acute phase, because it is possible to measure the cerebral blood flow, the oxygen extraction rate and the local oxygen consumption. (N.C.)

  6. Advance of molecular imaging with positron emission tomography

    International Nuclear Information System (INIS)

    Molecular imaging with positron emission tomography (PET) is an important field of molecular imaging. This article summarizes the fundamental of PET molecular imaging technique and its application in protein function, gene expression and gene therapy, receptor imaging, and blood-flow infusion and metabolism imaging. (authors)

  7. Amyloid-β positron emission tomography imaging probes

    DEFF Research Database (Denmark)

    Kepe, Vladimir; Moghbel, Mateen C; Långström, Bengt;

    2013-01-01

    number of factors appear to preclude these probes from clinical utilization. As the available "amyloid specific" positron emission tomography imaging probes have failed to demonstrate diagnostic value and have shown limited utility for monitoring therapeutic interventions in humans, a debate on their...

  8. Skeletal muscle perfusion measured by positron emission tomography during exercise

    NARCIS (Netherlands)

    Ament, W; Lubbers, J; Rakhorst, G; Vaalburg, W; Verkerke, GJ; Paans, AMJ; Willemsen, ATM

    1998-01-01

    The applicability of (H2O)-O-15-positron emission tomographic (PET) imaging for the assessment of skeletal muscle perfusion during exercise was investigated in five healthy subjects performing intermittent isometric contractions on a calf ergometer. The workload of the left calf muscles was kept con

  9. Positron emission tomography/computerized tomography in lung cancer

    OpenAIRE

    Sahiner, Ilgin; Vural, Gulin Ucmak

    2014-01-01

    Positron emission tomography (PET) using 2-(18F)-flouro-2-deoxy-D-glucose (FDG) has emerged as a useful tool in the clinical work-up of lung cancer. This review article provides an overview of applications of PET in diagnosis, staging, treatment response evaluation, radiotherapy planning, recurrence assessment and prognostication of lung cancer.

  10. 3D fast reconstruction in positron emission tomography

    International Nuclear Information System (INIS)

    The issue of long reconstruction times in positron emission tomography (PET) has been addressed from several points of view, resulting in an affordable dedicated system capable of handling routine 3D reconstructions in a few minutes per frame : on the hardware side using fast processors and a parallel architecture, and on the software side, using efficient implementation of computationally less intensive algorithms

  11. Increased brain amyloid deposition in patients with a lifetime history of major depression: evidenced on {sup 18}F-florbetapir (AV-45/Amyvid) positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kuan-Yi; Chen, Chia-Hsiang; Liu, Chia-Yih [Chang Gung Memorial Hospital and Chang Gung University, Department of Psychiatry, Tao-Yuan (China); Hsiao, Ing-Tsung; Hsieh, Chia-Ju [Chang Gung Memorial Hospital, Department of Nuclear Medicine and Molecular Imaging Center, Tao-Yuan (China); Chang Gung University, Department of Medical Imaging and Radiological Sciences and Healthy Aging Research Center, Tao-Yuan (China); Chen, Cheng-Sheng [Kaohsiung Medical University Hospital, Department of Psychiatry, Kaohsiung (China); Wai, Yau-Yau [Chang Gung Memorial Hospital, Department of Radiology, Tao-Yuan (China); Chang, Chee-Jen [Chang Gung University, Graduate Institute of Clinical Medical Science, Tao-Yuan (China); Chang Gung University, Clinical Informatics and Medical Statistics Research Center, Tao-Yuan (China); Chang Gung Memorial Hospital, Biostatistical Center for Clinical Research, Tao-Yuan (China); Tseng, Hsiao-Jung [Chang Gung Memorial Hospital, Biostatistical Center for Clinical Research, Tao-Yuan (China); Yen, Tzue-Chen; Lin, Kun-Ju [Chang Gung University, Department of Medical Imaging and Radiological Sciences and Healthy Aging Research Center, Tao-Yuan (China); Chang Gung Memorial Hospital, Department of Nuclear Medicine and Molecular Imaging Center, Tao-Yuan (China)

    2014-04-15

    The literature suggests that a history of depression is associated with an increased risk of developing Alzheimer's disease (AD). The aim of this study was to examine brain amyloid accumulation in patients with lifetime major depression using {sup 18}F-florbetapir (AV-45/Amyvid) PET imaging in comparison with that in nondepressed subjects. The study groups comprised 25 depressed patients and 11 comparison subjects who did not meet the diagnostic criteria for AD or amnestic mild cognitive impairment. Vascular risk factors, homocysteine and apolipoprotein E (ApoE) genotype were also examined. The standard uptake value ratio (SUVR) of each volume of interest was analysed using whole the cerebellum as the reference region. Patients with a lifetime history of major depression had higher {sup 18}F-florbetapir SUVRs in the precuneus (1.06 ± 0.08 vs. 1.00 ± 0.06, p = 0.045) and parietal region (1.05 ± 0.08 vs. 0.98 ± 0.07, p = 0.038) than the comparison subjects. Voxel-wise analysis revealed a significantly increased SUVR in depressed patients in the frontal, parietal, temporal and occipital areas (p < 0.01). There were no significant associations between global {sup 18}F-florbetapir SUVRs and prior depression episodes, age at onset of depression, or time since onset of first depression. Increased {sup 18}F-florbetapir binding values were found in patients with late-life major depression relative to comparison subjects in specific brain regions, despite no differences in age, sex, education, Mini Mental Status Examination score, vascular risk factor score, homocysteine and ApoE ε4 genotype between the two groups. A longitudinal follow-up study with a large sample size would be worthwhile. (orig.)

  12. Increased brain amyloid deposition in patients with a lifetime history of major depression: evidenced on 18F-florbetapir (AV-45/Amyvid) positron emission tomography

    International Nuclear Information System (INIS)

    The literature suggests that a history of depression is associated with an increased risk of developing Alzheimer's disease (AD). The aim of this study was to examine brain amyloid accumulation in patients with lifetime major depression using 18F-florbetapir (AV-45/Amyvid) PET imaging in comparison with that in nondepressed subjects. The study groups comprised 25 depressed patients and 11 comparison subjects who did not meet the diagnostic criteria for AD or amnestic mild cognitive impairment. Vascular risk factors, homocysteine and apolipoprotein E (ApoE) genotype were also examined. The standard uptake value ratio (SUVR) of each volume of interest was analysed using whole the cerebellum as the reference region. Patients with a lifetime history of major depression had higher 18F-florbetapir SUVRs in the precuneus (1.06 ± 0.08 vs. 1.00 ± 0.06, p = 0.045) and parietal region (1.05 ± 0.08 vs. 0.98 ± 0.07, p = 0.038) than the comparison subjects. Voxel-wise analysis revealed a significantly increased SUVR in depressed patients in the frontal, parietal, temporal and occipital areas (p 18F-florbetapir SUVRs and prior depression episodes, age at onset of depression, or time since onset of first depression. Increased 18F-florbetapir binding values were found in patients with late-life major depression relative to comparison subjects in specific brain regions, despite no differences in age, sex, education, Mini Mental Status Examination score, vascular risk factor score, homocysteine and ApoE ε4 genotype between the two groups. A longitudinal follow-up study with a large sample size would be worthwhile. (orig.)

  13. Caffeine and human cerebral blood flow: A positron emission tomography study

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) was used to quantify the effect of caffeine on whole brain and regional cerebral blood flow (CBF) in humans. A mean dose of 250 mg of caffeine produced approximately a 30% decrease in whole brain CBF; regional differences in caffeine effect were not observed. Pre-caffeine CBF strongly influenced the magnitude of the caffeine-induced decrease. Caffeine decreased paCO2 and increased systolic blood pressure significantly; the change in paCO2 did not account for the change in CBF. Smaller increases in diastolic blood pressure, heart rate, plasma epinephrine and norepinephrine, and subjectively reported anxiety were also observed

  14. Fluorine-18-fluorodeoxyglucose positron emission tomography (PET) brain imaging patterns in patients with suspected X-linked dystonia parkinsonism (study in progress)

    International Nuclear Information System (INIS)

    Objective: X-linked dystonia-parkinsonism (XDP or Lubag) is an adult-onset dystonia syndrome that afflicts mostly Filipino men from the island of Panay, Philippines.It starts focally and becomes generalized or multifocal after the first five years. Parkinsonism is commonly encountered as the initial symptom before the onset of dystonia. Patients may manifest a wide spectrum of movement disorders, including myoclonus, chorea, akathisia, ballism and myorhythmia. Diagnosis is based on the clinical presentation, and the establishment of an x-linked recessive pattern of inheritance and maternal roots from the Panay Islands. Neuroimaging in advanced cases have demonstrated caudate and putaminal atrophy. Previous studies using PET have shown selective reduction in normalized striatal glucose metabolism. The purpose of this study is to describe the FDG distribution using PET imaging in Filipino patients with suspected or confirmed Lubag in various stages of their disease in order to determine if FDG-PET can be used in the initial diagnosis and staging of the disease. Methods and results: All patients presenting to the Movement Disorders Center of St. Lukes Medical Center with dystonia and Parkinsonism symptoms with X-linked recessive inheritance pattern and maternal roots traceable to the Panay Islands were sent for a Brain FDG PET Scan. Seven male patients with various movement disorders (dysarthria, face dystonia, Parkinsonism, hemibalismus, involuntary movements and rest tremors) with duration of symptoms from 1 to 5 years underwent a PET scan. All patients had non visualized bilateral putamen, four had hypometabolic caudate nuclei, one had intense (hypermetabolic) caudate nuclei. CT scan and MRI did not show any findings which may explain the movement disorder symptoms. More patients are being collected and gene typing is planned for some patients. Conclusions: This small series of patients demonstrate that patients with the phenotypic characteristics of X

  15. Positron emission particle tracking-Application and labelling techniques

    Institute of Scientific and Technical Information of China (English)

    David J.Parker; Xianfeng Fan

    2008-01-01

    The positron emission particle tracking (PEPT) technique has been widely used in science and engineering to obtain detailed information on the motion and flow fields of fluids or granular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of granular materials in chemical reactors, granulators, mixers, dryers, rotating kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the design, operational conditions for a wide range of industrial process systems, and to evaluate modelling work. The technique is based on tracking radioactively labelled particles (up to three particles) by detecting the pairs of back-to-back 511 ke V -γ-rays arising from annihilation of emitted positrons. It therefore involves a positron camera, location algorithms for calculating the tracer location and speed, and tracer labelling techniques. This paper will review the particle tracking technique from tracking algorithm, tracer labelling to their application.

  16. Positron emission tomography in the Rett syndrome

    International Nuclear Information System (INIS)

    A consistent constellation of clinical signs and symptoms define the Rett syndrome, the most prominent of which are disorders of movement and tone. Preliminary pathologic and neurochemical data indicate predominant involvement of the nigrostriatal dopaminergic pathways and the cholinergic system of the basal forebrain region. The age of onset differentiates the Rett syndrome from Alzheimer and Parkinson disease with similar lesions. PET scanning makes it possible to relate the chemistry of the brain to function by measuring the number and affinity of neuroreceptors, metabolism in specific brain regions, and provide important determinants of the underlying mechanisms in disease states. (author)

  17. Positron emission tomography: a new paradigm in cancer management

    International Nuclear Information System (INIS)

    The National Cancer Institute (NCI) is currently building a positron emission tomography facility that will house a cyclotron and a PET fusion scanner. lt should be operational as of december 2007, being a cancer dedicated national referral center, the NCI should provide both positron-emitting radiopharmaceuticals and medical services to institutions and patients nationwide. PET technology provides metabolic information that has been documented to be useful in patient care. The properties of positron decay allow accurate imaging of the in vivo distribution of positron-emitting radiopharmaceuticals. a wide array of positron-emitting radiopharmaceuticals has been used to characterize multiple physiologic and pathologic states. The major clinical PET applications are in cancer patients using fluorine-18 fluorodeoxyglucose (FDG). FDG, an analogue of glucose, accumulates in most tumors in a greater amount than it does in normal tissue. PET is being used in diagnosis and follow-up of several malignancies, and the list of articles supporting its use continues to grow. in this article, the instrumentation aspects of PET are described and most of the clinical applications in oncology are described

  18. F-18 fluoro-d-glucose positron emission tomography/computed tomography in a patient with corticobasal degeneration

    OpenAIRE

    Marti, Alejandro

    2015-01-01

    Corticobasal degeneration is a rare neurodegenerative disorder that often eludes clinical diagnosis. The present case shows the F-18 fluoro-d-glucose positron emission tomography/computed tomography (PET/CT) of a 62-year-old man with a progressive movement disorder with asymmetric features. PET/CT examination showed a markedly right-brain hemispheric hypometabolism also involving basal ganglia.

  19. F-18 fluoro-d-glucose positron emission tomography/computed tomography in a patient with corticobasal degeneration

    International Nuclear Information System (INIS)

    Corticobasal degeneration is a rare neurodegenerative disorder that often eludes clinical diagnosis. The present case shows the F-18 fluoro-d-glucose positron emission tomography/computed tomography (PET/CT) of a 62-year-old man with a progressive movement disorder with asymmetric features. PET/CT examination showed a markedly right-brain hemispheric hypometabolism also involving basal ganglia

  20. The electronics system for the LBNL positron emission mammography (PEM) camera

    CERN Document Server

    Moses, W W; Baker, K; Jones, W; Lenox, M; Ho, M H; Weng, M

    2001-01-01

    Describes the electronics for a high-performance positron emission mammography (PEM) camera. It is based on the electronics for a human brain positron emission tomography (PET) camera (the Siemens/CTI HRRT), modified to use a detector module that incorporates a photodiode (PD) array. An application-specified integrated circuit (ASIC) services the photodetector (PD) array, amplifying its signal and identifying the crystal of interaction. Another ASIC services the photomultiplier tube (PMT), measuring its output and providing a timing signal. Field-programmable gate arrays (FPGAs) and lookup RAMs are used to apply crystal-by-crystal correction factors and measure the energy deposit and the interaction depth (based on the PD/PMT ratio). Additional FPGAs provide event multiplexing, derandomization, coincidence detection, and real-time rebinning. Embedded PC/104 microprocessors provide communication, real-time control, and configure the system. Extensive use of FPGAs make the overall design extremely flexible, all...

  1. Positron emission tomography (PET) in psychiatry

    International Nuclear Information System (INIS)

    Currently, clinical PET is mainly useful in psychiatry and related areas for differential diagnosis of dementia. In dementia of Alzheimer type reductions of glucose metabolism are found mainly in the temporoparietal assocaiton cortex, in Pick's disease mainly in the frontal cortex, and in Huntington's disease in the striatum. Other demential diseases usually show less toposelective metabolic impairment. In the future, new diagnostic possibilities may arise from analysis of functional stimulation of specific brain areas and from the use of ligands for specific neurotransmitter systems. (orig.)

  2. Positron emission tomography, physical bases and comparaison with other techniques

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a medical imaging technique that measures the three-dimensional distribution of molecules marked by a positron-emitting particle. PET has grown significantly in clinical fields, particularly in oncology for diagnosis and therapeutic follow purposes. The technical evolutions of this technique are fast. Among the technical improvements, is the coupling of the PET scan with computed tomography (CT). PET is obtained by intravenous injection of a radioactive tracer. The marker is usually fluorine (18F) embedded in a glucose molecule forming the 18-fluorodeoxyglucose (FDG-18). This tracer, similar to glucose, binds to tissues that consume large quantities of the sugar such cancerous tissue, cardiac muscle or brain. Detection using scintillation crystals (BGO, LSO, LYSO) suitable for high energy (511keV) recognizes the lines of the gamma photons originating from the annihilation of a positron with an electron. The electronics of detection or coincidence circuit is based on two criteria: a time window, of about 6 to 15 ns, and an energy window. This system measures the true coincidences that correspond to the detection of two photons of 511 kV from the same annihilation. Most PET devices are constituted by a series of elementary detectors distributed annularly around the patient. Each detector comprises a scintillation crystal matrix coupled to a finite number (4 or 6) of photomultipliers. The electronic circuit, or the coincidence circuit, determines the projection point of annihilation by means of two elementary detectors. The processing of such information must be extremely fast, considering the count rates encountered in practice. The information measured by the coincidence circuit is then positioned in a matrix or sinogram, which contains a set of elements of a projection section of the object. Images are obtained by tomographic reconstruction by powerful computer stations equipped with a software tools allowing the analysis and

  3. Findings in Positron Emission Tomography of Brain in Rats with Syndrome of Stagnation of Liver-Qi%肝气郁结模型大鼠正电子发射脑功能成像研究

    Institute of Scientific and Technical Information of China (English)

    刘子旺; 赵海滨; 张秀静; 单保慈; 刘华; 贺立娟

    2011-01-01

    目的 探讨肝气郁结证在特定脑区功能的改变.方法10只Wista大鼠采用慢性应激结合孤养方法制备肝气郁结证大鼠模型,分别于造模前后进行氟18脱氧葡萄糖(18F-FDG)PET正电子扫描,应用SPM2图像分析软件对造模前、造模后数据进行双样本t检验.结果葡萄糖代谢减低脑区(P<0.001)有左侧额叶、顶叶、下丘脑,双侧后扣带回,右侧前扣带回.葡萄糖代谢升高脑区(P<0.001)有左侧海马旁回、岛叶、颞叶、额叶,右侧基底核、丘脑.结论肝气郁结证可引起特定脑区的功能改变.%Objective To explore the characteristics of brain function in rats with Stagnation of Liver-qi Syndrome. Methods Model of Stagnation of Liver-qi was made with chronic stress combined with isolated raising in 10 normal Wistar rats. They were scanned with positron emission tomography (PET) before and after modeling. Data analysis was carried out using SPM (statistical parametric mapping 2) in MATLAB software. Results After modeling, the glucose metabolism decreased (P<0.001) in left frontal lobe, parietal lobe, hypothalamus; bilateral posterior cingulate; right anterior cingulate, while the glucose metabolism increased (P<0.001) in left parahippocampal gyrus, insu-la, temporal lobe, frontal lobe; right basal ganglia, thalamus. Conclusion The function of some cerebral areas can be changed undergoing Stagnation of Liver-qi Syndrome.

  4. A novel clustering approach to positron emission particle tracking

    Science.gov (United States)

    Wiggins, Cody; Santos, Roque; Ruggles, Arthur

    2016-03-01

    A novel approach to positron emission particle tracking is presented based on determining regions of space with high density of line of response crossing via clustering. The method is shown to be able to accurately track multiple particles in systems where the number of particles is unknown and in which particles can enter and leave the field of view of the scanning system. This method is explored in various environments and its parametric dependence is studied.

  5. Microfluidics for Positron Emission Tomography (PET) Imaging Probe Development

    OpenAIRE

    Wang, Ming-Wei; Lin, Wei-Yu; Liu, Kan; Masterman-Smith, Michael; Shen, Clifton Kwang-Fu

    2010-01-01

    Due to increased needs for Positron Emission Tomography (PET) scanning, high demands for a wide variety of radiolabeled compounds will have to be met by exploiting novel radiochemistry and engineering technologies to improve the production and development of PET probes. The application of microfluidic reactors to perform radiosyntheses is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional labeling systems. Microfluidic-based r...

  6. Positron emission tomography (PET) evaluation of abdominal aortic aneurysm (AAA)

    OpenAIRE

    SakalihasanN, Natzi; Van Damme, Hendrik; Gomez, P.; RIGO, PIERRE; Lapiere, C. M.; Nusgens, Betty; Limet, Raymond

    2002-01-01

    Background: aneurysmal disease is associated with all inflammatory Cell infiltrate and enzymatic degradation of the vessel wall. Aim of the study: to detect increased metabolic activity in abdominal aortic aneurysms (AAA) by means of positron emission tomography (PET-imaging). Study design: twenty-six patients with AAA underwent PET-imaging Results: in tell patients, PET-imaging revealed increased, fluoro-deoxy-glucose (18-FDG) uptake at the level of the aneurysm. Patients with positive PET-i...

  7. Introducing Positron Emission Tomography (PET) in Clinical Practice

    OpenAIRE

    Janevik-Ivanovska, Emilija; Avmedovski, Fatmir; Yamamoto, Mayumi; Bhonsle, Uday

    2009-01-01

    Positron emission tomography (PET) is a major diagnostic imaging technique predominantly used in determining the presence and severity of cancers, neurological conditions, and cardiovascular diseases. It is currently the most effective way to check for cancer recurrences and it offers significant advantages over other forms of imaging such as computed tomography (CT) or magnetic resonance imaging (MRI) scans in detecting disease in many patients. In the USA, an estimated 1 129 900 clinical PE...

  8. ENVISION, developing Positron Emission Tomography for particle therapy

    CERN Multimedia

    2013-01-01

    Particle therapy is an advanced technique of cancer radiation therapy, using protons or other ions to target the cancerous mass. ENVISION aims at developing medical imaging tools to improve the dose delivery to the patient, to ensure a safer and more effective treatment. The animation illustrates the use of Positron Emission Tomography (PET) for monitoring the dose during treatment. Produced by: CERN KT/Life Sciences and ENVISION Project Management: Manuela Cirilli 3D animation: Jeroen Huijben, Nymus3d

  9. Nonhuman Primate Positron Emission Tomography Neuroimaging in Drug Abuse Research

    OpenAIRE

    Howell, Leonard Lee; Murnane, Kevin Sean

    2011-01-01

    Positron emission tomography (PET) neuroimaging in nonhuman primates has led to significant advances in our current understanding of the neurobiology and treatment of stimulant addiction in humans. PET neuroimaging has defined the in vivo biodistribution and pharmacokinetics of abused drugs and related these findings to the time course of behavioral effects associated with their addictive properties. With novel radiotracers and enhanced resolution, PET neuroimaging techniques have also charac...

  10. Positron emission holography: A new method of creating positron camera images

    International Nuclear Information System (INIS)

    By simulating the presence of a Fresnel zone plate in a camera designed for positron emission tomography (PET), a hologram can be synthesized which permits full three-dimensional images of the positron distribution in the original object to be rapidly constructed. The method requires no additional apparatus to a standard PET system, which is also operated in the usual way. The trajectory of each photon pair, detected in coincidence, is weighted as if it had passed through a zone plate optimised to suit the problem, before recording its intercept with a (single) plane to produce the hologram. The final image is created by calculating the diffraction pattern of monochromatic light passed through this hologram; it may also be created optically. The method is described in detail and its attractions discussed. Results are presented of some simple objects obtained from holograms produced from PET camera data, in comparison with images created by conventional back-projection processing of the same data. (orig.)

  11. Measurement of neurotransmitters with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Laruelle, M.; Erritzoe, D.; Abi-Dargham, A.; Huang, Y. [Columbia Univ., Coll. of Physicians and Surgeons, Dept. of Psychiatry and Radiology, New York, NY (United States)

    2003-09-01

    Over the last decade several groups have provided evidence that PET and SPECT neuro-receptor imaging techniques might be applied to measure fluctuations of dopamine (DA) synaptic concentrations in the living human brain. It is generally believed that changes in the in vivo binding of radioligands following acute changes in transmitter levels are driven by binding competition. These techniques have been very successful in giving dynamic information regarding DA transmission. However, the development of similar techniques to study other neurotransmitter systems has proven difficult. This review paper first summarizes endogenous competition studies performed in animals and humans. The validity of the model underlying the interpretation of these data is critically assessed. Emerging data suggest that simple binding competition might not be the only phenomenon involved in these interactions; receptor trafficking might play an important role. A better understanding of the radioligand properties that determine sensitivity to endogenous molecules might facilitate the selective development of this type of radiotracer. (authors)

  12. Imaging opiate receptors with positron emission tomography

    International Nuclear Information System (INIS)

    Opiate receptors exist in the mammalian brain and are thought to meditate the diverse pharmacological actions of the opiates, such as analgesia, euphoria, and sedation. The 4-carbomethoxyl derivatives of fentanyl, such as lofentanil and R31833 (4-carbomethoxyfentanyl) bind to the opiate receptor with high affinity. C-11 R31833 was synthesized by reacting C-11 methyl iodide with the appropriate carboxylate. Male ICR mice were injected intravenously with C-11 R31833 (5μg/kg), killed 30 minutes later, and the brains rapidly dissected. The thalami, striata, and cerebral cortex are rich in opiate receptors, but the cerebellum contains a very low concentration of opiate receptors. The thalamus/cerebellum and striatum/cerebellum activity ratios, calculated per mg of wet tissue, were 4.1 and 5.2 respectively. Coinjection of 5mg/kg naloxone reduced the ratios to 1.1, which indicates that the preferential localization of C-11 R31833 in the thalami and striata is due to binding to opiate is due to binding to opiate receptors. A 22 kg anesthetized male baboon was imaged using the NeuroECAT after injection of 18.9 mCi of C-11 R13833 (0.50 μg/kg, specific activity 616 Ci/mmole at time of injection). From 15-70 minutes after injection preferential accumulation of activity could be seen in the thalami, caudate nuclei, and cerebral cortex and, conversely, low activity was demonstrated in the cerebellum. At one hour postinjection the maximum measured caudate/cerebellum activity ratio per pixel was 2.9. For the NeuroECAT the recovery coefficient for the baboon caudate is ca. 0.2-0.3, and therefore the actual caudate/cerebellum ratio is ca. 10-15

  13. Imaging opiate receptors with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Frost, J.J.; Dannals, R.F.; Ravert, H.T.; Wilson, A.A.; Wong, D.F.; Links, J.M.; Burns, H.D.; Kuhar, M.J.; Snyder, S.H.; Wagner, H.N. Jr.

    1984-01-01

    Opiate receptors exist in the mammalian brain and are thought to meditate the diverse pharmacological actions of the opiates, such as analgesia, euphoria, and sedation. The 4-carbomethoxyl derivatives of fentanyl, such as lofentanil and R31833 (4-carbomethoxyfentanyl) bind to the opiate receptor with high affinity. C-11 R31833 was synthesized by reacting C-11 methyl iodide with the appropriate carboxylate. Male ICR mice were injected intravenously with C-11 R31833 (5..mu..g/kg), killed 30 minutes later, and the brains rapidly dissected. The thalami, striata, and cerebral cortex are rich in opiate receptors, but the cerebellum contains a very low concentration of opiate receptors. The thalamus/cerebellum and striatum/cerebellum activity ratios, calculated per mg of wet tissue, were 4.1 and 5.2 respectively. Coinjection of 5mg/kg naloxone reduced the ratios to 1.1, which indicates that the preferential localization of C-11 R31833 in the thalami and striata is due to binding to opiate is due to binding to opiate receptors. A 22 kg anesthetized male baboon was imaged using the NeuroECAT after injection of 18.9 mCi of C-11 R13833 (0.50 ..mu..g/kg, specific activity 616 Ci/mmole at time of injection). From 15-70 minutes after injection preferential accumulation of activity could be seen in the thalami, caudate nuclei, and cerebral cortex and, conversely, low activity was demonstrated in the cerebellum. At one hour postinjection the maximum measured caudate/cerebellum activity ratio per pixel was 2.9. For the NeuroECAT the recovery coefficient for the baboon caudate is ca. 0.2-0.3, and therefore the actual caudate/cerebellum ratio is ca. 10-15.

  14. Clinical cardiac positron emission tomography: State of the art

    International Nuclear Information System (INIS)

    Cardiac positron emission tomography (PET) has evolved rapidly from a relatively esoteric research tool into clinical applications providing unique, quantitative information on myocardial perfusion, metabolism, and cell membrane function and having a potentially significant impact on cardiovascular medicine. Although there are many different positron radionuclides for imaging diverse myocardial behavior, three radionuclides have reached accepted clinical utility. Cardiac PET using nitrogen-13-ammonia, rubidium-82, and fluoro-18-deoxyglucose has proved accurate and definitive in multiple university and private-practice sites for diagnosing and assessing severity and location of coronary artery disease in symptomatic or asymptomatic patients, for identifying injured but viable myocardium potentially salvageable by revascularization, and for ruling out clinically significant coronary artery stenosis with a high specificity in patients who might otherwise undergo coronary arteriography to document the absence of significant disease. 89 references

  15. Investigation of granular impact using positron emission particle tracking

    KAUST Repository

    Marston, Jeremy O.

    2015-04-01

    We present results from an experimental study of granular impact using a combination of high-speed video and positron emission particle tracking (PEPT). The PEPT technique exploits the annihilation of photons from positron decay to determine the position of tracer particles either inside a small granular bed or attached to the object which impacts the bed. We use dense spheres as impactors and the granular beds are comprised of glass beads which are fluidised to achieve a range of different initial packing states. For the first time, we have simultaneously investigated both the trajectory of the sphere, the motion of particles in a 3-D granular bed and particles which jump into the resultant jet, which arises from the collapse of the cavity formed by the impacting sphere.

  16. Correlation of 18F-fluoroethyl tyrosine positron-emission tomography uptake values and histomorphological findings by stereotactic serial biopsy in newly diagnosed brain tumors using a refined software tool

    Directory of Open Access Journals (Sweden)

    Lopez WO

    2015-12-01

    Full Text Available William Omar Contreras Lopez,1,2 Joacir Graciolli Cordeiro,1 Ulrich Albicker,3 Soroush Doostkam,4 Guido Nikkhah,1,5 Robert D Kirch,6 Michael Trippel,1 Thomas Reithmeier1,7 1Department of Stereotactic and Functional Neurosurgery, University Medical Center Freiburg, Freiburg im Breisgau, Germany; 2Division of Functional Neurosurgery, Department of Neurology, Hospital das Clinicas, University of São Paulo Medical School, São Paulo, Brazil; 3Inomed, Emmendingen, 4Department of Neuropathology, University Medical Center Freiburg, Freiburg im Breisgau, 5Department of Neurosurgery, University Clinic Erlangen, Erlangen, 6Neuroelectronic Systems, Department of Neurosurgery, University Medical Center Freiburg, Freiburg im Breisgau, 7Department of Neurosurgery, Schwabing Academic Teaching Hospital of Technical University and Ludwig Maximilian University of Munich, Munich, Germany Background: Magnetic resonance imaging (MRI is the standard neuroimaging method to diagnose neoplastic brain lesions, as well as to perform stereotactic biopsy surgical planning. MRI has the advantage of providing structural anatomical details with high sensitivity, though histological specificity is limited. Although combining MRI with other imaging modalities, such as positron-emission tomography (PET, has proven to increment specificity, exact correlation between PET threshold uptake ratios (URs and histological diagnosis and grading has not yet been described.Objectives: The aim of this study was to correlate exactly the histopathological criteria of the biopsy site to its PET uptake value with high spatial resolution (mm3, and to analyze the diagnostic value of PET using the amino acid O-(2-[18F]fluoroethyl-L-tyrosine (18F-FET PET in patients with newly diagnosed brain lesions in comparison to histological findings obtained from stereotactic serial biopsy.Patients and methods: A total of 23 adult patients with newly diagnosed brain tumors on MRI were enrolled in this study

  17. Clinical correlates of decreased anteroposterior metabolic gradients in positron emission tomography (PET) of schizophrenic patients

    International Nuclear Information System (INIS)

    The finding in schizophrenic patients of a reversal of the normal frontal to posterior pattern of brain metabolic activity with positron emission tomography (PET) is of interest, but its relevance to psychopathology is unknown. Using PET, the authors studied 21 patients with chronic schizophrenia and 21 age- and sex-matched control subjects. Although eight of the 21 patients and only one of the control subjects showed a relatively lower anteroposterior metabolic gradient, no clinical correlates of this finding were noted. In addition, cerebral atrophy, as determined by CAT scan, was not associated with this aberrant metabolic pattern

  18. Clinical correlates of decreased anteroposterior metabolic gradients in positron emission tomography (PET) of schizophrenic patients

    Energy Technology Data Exchange (ETDEWEB)

    DeLisi, L.E.; Buchsbaum, M.S.; Holcomb, H.H.; Dowling-Zimmerman, S.; Pickar, D.; Boronow, J.; Morihisa, J.M.; van Kammen, D.P.; Carpenter, W.; Kessler, R.

    1985-01-01

    The finding in schizophrenic patients of a reversal of the normal frontal to posterior pattern of brain metabolic activity with positron emission tomography (PET) is of interest, but its relevance to psychopathology is unknown. Using PET, the authors studied 21 patients with chronic schizophrenia and 21 age- and sex-matched control subjects. Although eight of the 21 patients and only one of the control subjects showed a relatively lower anteroposterior metabolic gradient, no clinical correlates of this finding were noted. In addition, cerebral atrophy, as determined by CAT scan, was not associated with this aberrant metabolic pattern.

  19. Cerebrospinal fluid analysis detects cerebral amyloid-β accumulation earlier than positron emission tomography

    OpenAIRE

    Palmqvist, Sebastian; Mattsson, Niklas; Hansson, Oskar; ,

    2016-01-01

    See Rabinovici (doi:10.1093/brain/aww025) for a scientific commentary on this article. Cerebral accumulation of amyloid-β is thought to be the starting mechanism in Alzheimer’s disease. Amyloid-β can be detected by analysis of cerebrospinal fluid amyloid-β42 or amyloid positron emission tomography, but it is unknown if any of the methods can identify an abnormal amyloid accumulation prior to the other. Our aim was to determine whether cerebrospinal fluid amyloid-β42 change before amyloid PET ...

  20. Drug washout issues in studies of cerebral metabolism by positron emission tomography in psychiatric patients

    International Nuclear Information System (INIS)

    Many studies of brain glucose utilization by positron emission tomography attempt to describe the modifications of the brain activity during psychiatric diseases. A major difficulty in such studies is the necessity to assess patients free of pharmacological treatment, in order to relate the measured changes in glucose utilization to the pathopsychology, and not to a drug effect. In this paper are reviewed the arguments from the literature allowing to estimate the drug washout time for considering the patients as drug-free. The review is focussed on the known effects of the psychotrops on brain glucose utilization. This time is approximately six months for the neuroleptics given orally, one month for antidepressants, and five and a half half-lives for benzodiazepines. Alternative research strategies for avoiding a long drug washout are mentioned, and ethical limitations are considered. (author)

  1. Molecular Imaging of Transporters with Positron Emission Tomography

    Science.gov (United States)

    Antoni, Gunnar; Sörensen, Jens; Hall, Håkan

    Positron emission tomography (PET) visualization of brain components in vivo is a rapidly growing field. Molecular imaging with PET is also increasingly used in drug development, especially for the determination of drug receptor interaction for CNS-active drugs. This gives the opportunity to relate clinical efficacy to per cent receptor occupancy of a drug on a certain targeted receptor and to relate drug pharmacokinetics in plasma to interaction with target protein. In the present review we will focus on the study of transporters, such as the monoamine transporters, the P-glycoprotein (Pgp) transporter, the vesicular monoamine transporter type 2, and the glucose transporter using PET radioligands. Neurotransmitter transporters are presynaptically located and in vivo imaging using PET can therefore be used for the determination of the density of afferent neurons. Several promising PET ligands for the noradrenaline transporter (NET) have been labeled and evaluated in vivo including in man, but a really useful PET ligand for NET still remains to be identified. The most promising tracer to date is (S,S)-[18F]FMeNER-D2. The in vivo visualization of the dopamine transporter (DAT) may give clues in the evaluation of conditions related to dopamine, such as Parkinson's disease and drug abuse. The first PET radioligands based on cocaine were not selective, but more recently several selective tracers such as [11C]PE2I have been characterized and shown to be suitable as PET radioligands. Although there are a large number of serotonin transporter inhibitors used today as SSRIs, it was not until very recently, when [11C]McN5652 was synthesized, that this transporter was studied using PET. New candidates as PET radioligands for the SERT have subsequently been developed and [11C]DASB and [11C]MADAM and their analogues are today the most promising ligands. The existing radioligands for Pgp transporters seem to be suitable tools for the study of both peripheral and central drug

  2. Methods and clinical applications of positron emission tomography in endocrinology

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) allows to detect in coincidence photons issued from annihilation between positrons and electrons nearby situated. Tomographic detection (plane by plane) and tomographic reconstruction will lead to the quantitation of radioactive distribution per voxel, in the organ of interest. Recent tomographs can acquire simultaneously several transaxial slices, with a high sensitivity and a spatial resolution of 3-5 mm. Commonly used positron emitters have a short half-life: 2, 10, 20 and 110 min for 150, 13N, 11C and 18F, respectively. The use of these isotopes requires on line production of radionuclides and synthesis of selected molecules. In endocrinology, PET allows among others to study noninvasively the receptor density of hormonodependent neoplasms such as breast, uterus, prostate tumors and prolactinomas. These last tumors represent a particular entity because of several combined characteristics: high turnover rate of amino acids, high density of dopaminergic receptors and response to bromocriptine (analogue of dopamine inhibiting the secretion of prolactine) in relation to the level of receptors. Because PET permits to evaluate the density of dopaminergic receptors and the metabolism of amino acids, theoretical response of the prolactinoma to bromocriptin can be predicted, the achieved therapeutic efficacy can be estimated and the long-term follow up of tumor growth can be assessed. This example illustrates the clinical value of PET in endocrinology

  3. The investigation of cerebrovascular disorders with positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) provides a non-invasive, regional, in vivo method to measure physiological parameters including cerebral blood flow, glucose and oxygen metabolism, blood volume, and pH. Measurement of these parameters not only enables a more complete understanding of the pathophysiology of acute cerebral ischemia and infarction, but provides objective criteria with which to better manage patients. This chapter will first discuss PET methodology and tracer techniques used in the investigation of patients with cerebrovascular disease and then describe the progress that has already resulted from applying these methods. 73 refs.; 7 figs

  4. Positron emission tomography: diagnostic imaging on a molecular level

    International Nuclear Information System (INIS)

    In human medicine positron emission tomography (PET) is a modern diagnostic imaging method. In the present paper we outline the physical principles of PET and give an overview over the main clinic fields where PET is being used, such as neurology, cardiology and oncology. Moreover, we present a current project in veterinary medicine (in collaboration with the Paul Scherrer Institute and the University Hospital Zurich), where a hypoxia tracer is applied to dogs and cats suffering from spontaneous tumors. Finally new developments in the field of PET were discussed

  5. Kinetic modeling in pre-clinical positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kuntner, Claudia [AIT Austrian Institute of Technology GmbH, Seibersdorf (Austria). Biomedical Systems, Health and Environment Dept.

    2014-07-01

    Pre-clinical positron emission tomography (PET) has evolved in the last few years from pure visualization of radiotracer uptake and distribution towards quantification of the physiological parameters. For reliable and reproducible quantification the kinetic modeling methods used to obtain relevant parameters of radiotracer tissue interaction are important. Here we present different kinetic modeling techniques with a focus on compartmental models including plasma input models and reference tissue input models. The experimental challenges of deriving the plasma input function in rodents and the effect of anesthesia are discussed. Finally, in vivo application of kinetic modeling in various areas of pre-clinical research is presented and compared to human data.

  6. Development of radioisotopically labeled compounds for clinical positron emission tomography

    International Nuclear Information System (INIS)

    It is its quantitative imaging capacity with high spatial resolution that makes positron emission tomography a unique tool for the development of quantitative tracer kinetic studies for the measurement of physiological processes in man. Research success in this area will depend on the ingenuity of biomedical scientists in prioritizing the development of tracers. Choices must be made based on the importance of different physiological measurements, the capacity to synthesize an appropriate radioisotopically labeled compound for this measurement and the ability to determine an adequate kinetic model for its interpretation. Examples are given of these steps in the development of PET tracers at the NIMH. 17 refs.; 1 table

  7. Design of a volume-imaging positron emission tomograph

    International Nuclear Information System (INIS)

    Progress is reported in several areas of design of a positron volume imaging tomograph. As a means of increasing the volume imaged and the detector packing fraction, a lens system of detector light coupling is considered. A prototype layered scintillator detector demonstrates improved spatial resolution due to a unique Compton rejection capability.The conceptual design of a new mechanism for measuring scattered radiation during emission scans has been tested by Monte Carlo simulation. The problem of how to use effectively the resulting sampled scattered radiation projections is presented and discussed

  8. Positron Emission Tomography Imaging of Regional Pulmonary Perfusion and Ventilation

    OpenAIRE

    Musch, Guido; Venegas, Jose G.

    2005-01-01

    Positron emission tomography (PET) imaging is a noninvasive, quantitative method to assess pulmonary perfusion and ventilation in vivo. The core of this article focuses on the use of [13N]nitrogen (13N2) and PET to assess regional gas exchange. Regional perfusion and shunt can be measured with the 13N2–saline bolus infusion technique. A bolus of 13N2, dissolved in saline solution, is injected intravenously at the start of a brief apnea, while the tracer kinetics in the lung is measured by a s...

  9. Use of positron emission tomography in colorectal cancer

    International Nuclear Information System (INIS)

    The value of PET (Positron Emission Tomography) in colorectal cancer is presented. PET is a novel technique that uses F-18-FDG (fluorodeoxiglucose) to assess glucose metabolism by whole body imaging. It has been demonstrated that malignant cells have both increase of glucose uptake and utilization. In colorectal cancer, PET is indicated for staging, assess recurrence, liver metastasis and treatment follow-up. PET is more sensitive and specific than CT (Computed Tomography) and is cost effective. In 30% of cases PET may change patient management, avoiding unnecessary procedures (au)

  10. Positron emission tomography. Present status and Romanian perspectives

    International Nuclear Information System (INIS)

    Basic principles of the positron emission tomography (PET) are summarised. The main PET methods using short-lived radioisotopes (i.e.11 C, 13 N, 15 O, 18 F) are briefly reviewed. Three types of particle accelerators for radioisotopes production and medical uses (including radiotherapy), corresponding to the proton energy (Ep p p < 200 MeV) are presented. PET imaging equipment and procedures are discussed. Main radiopharmaceuticals based on beta decay for PET studies and their role in medicine is also described. Finally, perspectives for a PET program in Romania (Cyclotron + Radiochemistry + Tomograph ) are discussed. (author)

  11. Application of positron emission tomography in industrial research

    International Nuclear Information System (INIS)

    Positron Emission computed Tomography (PET) is a relatively new imaging technique, exploiting the 511 keV annihilation radiation characteristic of positron emitters. Although exclusively used till now in the field of nuclear medicine, the application of PET for the non-invasive, in-situ visualisation of processes of industrial interest is challenging, because PET can in principle be used to obtain quantitative, 2D/3D images of the flow and distribution of fluids inside process units, whose steel walls may be up to several centimeters thick. With the aid of a NeuroECAT positron tomographer the PET technique has been utilised to image important (model) processes in the petrochemical industry, using physical labelling of the phase to be imaged. First, the displacement of a brine/surfactant phase, labelled with 66Ga-EDTA, in a piece of reservoir rock was imaged. Secondly, the dehydration of water-in-oil emulsions was monitored dynamically by labelling the water phase with 68Ga-EDTA. The second study in particular demonstrates that in the presence of noisy data the image reconstruction method utilised strongly influences the results obtained. With the advent of PET in nuclear medicine the availability of short-lived positron emitting nuclides like 11C (t1/2 = 20 min), 13N (t1/2 = 10 min) and 150 (t1/2 = 2 min) has increased considerably, allowing the investigation of industrially important reactions by chemical labelling. Utilising the NeuroECAT in a special mode, the catalytic oxidation of carbon monoxide could be imaged in a model tubular reactor by using 11C-labelled CO, providing information about the kinetics of the individual reaction steps and interactions and about the degree of occupation of catalytically active sites. (author)

  12. An anatomically realistic brain phantom for quantification with positron tomography

    International Nuclear Information System (INIS)

    Phantom studies are useful in assessing and maximizing the accuracy and precision of quantification of absolute activity, assessing errors associated with patient positioning, and dosimetry. Most phantoms are limited by the use of simple shapes, which do not adequately reflect real anatomy. The authors have constructed an anatomically realistic life-size brain phantom for positron tomography studies. The phantom consists of separately fillable R + L caudates, R + L putamens, R + L globus passidus and cerebellum. These structures are contained in proper anatomic orientation within a fillable cerebrum. Solid ventricles are also present. The entire clear vinyl cerebrum is placed in a human skull. The internal brain structures were fabricated from polyester resin, with dimensions, shapes and sizes of the structures obtained from digitized contours of brain slices in the U.C.S.D. computerized brain atlas. The structures were filled with known concentrations of Ga-68 in water and scanned with our NeuroECAT. The phantom was aligned in the scanner for each structure, such that the tomographic slice passed through that structure's center. After calibration of the scanner with a standard phantom for counts/pixel uCi/cc conversion, the measured activity concentrations were compared with the actual concentrations. The ratio of measured to actual activity concentration (''recovery coefficient'') for the caudate was 0.33; for the putamen 0.42. For comparison, the ratio for spheres of diameters 9.5, 16,19 and 25.4 mm was 0.23, 0.54, 0.81, and 0.93. This phantom provides more realistic assessment of performance and allows calculation of correction factors

  13. Positron emission tomography: physics, instrumentation, and image analysis.

    Science.gov (United States)

    Porenta, G

    1994-01-01

    Positron emission tomography (PET) is a noninvasive diagnostic technique that permits reconstruction of cross-sectional images of the human body which depict the biodistribution of PET tracer substances. A large variety of physiological PET tracers, mostly based on isotopes of carbon, nitrogen, oxygen, and fluorine is available and allows the in vivo investigation of organ perfusion, metabolic pathways and biomolecular processes in normal and diseased states. PET cameras utilize the physical characteristics of positron decay to derive quantitative measurements of tracer concentrations, a capability that has so far been elusive for conventional SPECT (single photon emission computed tomography) imaging techniques. Due to the short half lives of most PET isotopes, an on-site cyclotron and a radiochemistry unit are necessary to provide an adequate supply of PET tracers. While operating a PET center in the past was a complex procedure restricted to few academic centers with ample resources, PET technology has rapidly advanced in recent years and has entered the commercial nuclear medicine market. To date, the availability of compact cyclotrons with remote computer control, automated synthesis units for PET radiochemistry, high-performance PET cameras, and user-friendly analysis workstations permits installation of a clinical PET center within most nuclear medicine facilities. This review provides simple descriptions of important aspects concerning physics, instrumentation, and image analysis in PET imaging which should be understood by medical personnel involved in the clinical operation of a PET imaging center. PMID:7941595

  14. Positron emission tomography: Physics, instrumentation, and image analysis

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a noninvasive diagnostic technique that permits reconstruction of cross-sectional images of the human body which depict the biodistribution of PET tracer substances. A large variety of physiological PET tracers, mostly based on isotopes of carbon, nitrogen, oxygen, and fluorine is available and allows the in vivo investigation of organ perfusion, metabolic pathways and biomolecular processes in normal and diseased states. PET cameras utilize the physical characteristics of positron decay to derive quantitative measurements of tracer concentrations, a capability that has so far been elusive for conventional SPECT (single photon emission computed tomography) imaging techniques. Due to the short half lives of most PET isotopes, an on-site cyclotron and a radiochemistry unit are necessary to provide an adequate supply of PET tracers. While operating a PET center in the past was a complex procedure restricted to few academic centers with ample resources. PET technology has rapidly advanced in recent years and has entered the commercial nuclear medicine market. To date, the availability of compact cyclotrons with remote computer control, automated synthesis units for PET radiochemistry, high-performance PET cameras, and userfriendly analysis workstations permits installation of a clinical PET center within most nuclear medicine facilities. This review provides simple descriptions of important aspects concerning physics, instrumentation, and image analysis in PET imaging which should be understood by medical personnel involved in the clinical operation of a PET imaging center. (author)

  15. Basic principles of 18F-fluoro-deoxyglucose positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography uses photons to receive regional information about dynamic, physiologic, and biochemical processes in the living body. A positron decay is measured indirectly by the simultaneous registration of both gamma rays created by the annihilation. The event is counted, if two directly opposite located detectors register gamma rays in coincidence. Unfortunately the detectors of a positron emission tomography system do not register only true coincident events. There are also scattered and random coincidences. Different types of positron tomographs are presented and scintillation crystals, which are in use for positron emission tomography are discussed. The 2D- and 3D-acquisition methods are described as well as preprocessing methods, such as correction for attenuation, scatter and dead time. For quantification the relative parameter standard uptake value (SUV) is explained. Finally hybrid systems, such as combined positron emission tomography/computed tomography scanners and the use of computed tomography data for attenuation correction are introduced. (author)

  16. Simulation of the annihilation emission of galactic positrons; Modelisation de l'emission d'annihilation des positrons Galactiques

    Energy Technology Data Exchange (ETDEWEB)

    Gillard, W

    2008-01-15

    Positrons annihilate in the central region of our Galaxy. This has been known since the detection of a strong emission line centered on an energy of 511 keV in the direction of the Galactic center. This gamma-ray line is emitted during the annihilation of positrons with electrons from the interstellar medium. The spectrometer SPI, onboard the INTEGRAL observatory, performed spatial and spectral analyses of the positron annihilation emission. This thesis presents a study of the Galactic positron annihilation emission based on models of the different interactions undergone by positrons in the interstellar medium. The models are relied on our present knowledge of the properties of the interstellar medium in the Galactic bulge, where most of the positrons annihilate, and of the physics of positrons (production, propagation and annihilation processes). In order to obtain constraints on the positrons sources and physical characteristics of the annihilation medium, we compared the results of the models to measurements provided by the SPI spectrometer. (author)

  17. A controlled study of positron-emission-tomography and positron-emission-tomography/computed tomography in differential diagnosis of solitary pulmonary nodules-report of 60 cases

    Institute of Scientific and Technical Information of China (English)

    DING Qi-yong; HUA Yan-qing; ZHANG Guo-zhen; ZHAO Jun; GUAN Yi-hui; GE Xiao-jun; MAO Ding-biao; ZUO Chuan-tao

    2005-01-01

    @@ The differential diagnosis of solitary pulmonary nodules (SPNs) remains a challenge. It is acknowledged that combining positron-emission tomography (PET) and computed tomography (CT) offers the most reliable noninvasive method for the diagnosis of SPNs.

  18. Caffeine and human cerebral blood flow: A positron emission tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, O.G.; Modell, J.G.; Hariharan, M. (Univ. of Michigan Medical Center, Ann Arbor (USA))

    1990-01-01

    Positron emission tomography (PET) was used to quantify the effect of caffeine on whole brain and regional cerebral blood flow (CBF) in humans. A mean dose of 250 mg of caffeine produced approximately a 30% decrease in whole brain CBF; regional differences in caffeine effect were not observed. Pre-caffeine CBF strongly influenced the magnitude of the caffeine-induced decrease. Caffeine decreased p{sub a}CO{sub 2} and increased systolic blood pressure significantly; the change in p{sub a}CO{sub 2} did not account for the change in CBF. Smaller increases in diastolic blood pressure, heart rate, plasma epinephrine and norepinephrine, and subjectively reported anxiety were also observed.

  19. 4.5 Tesla magnetic field reduces range of high-energy positrons -- Potential implications for positron emission tomography

    International Nuclear Information System (INIS)

    The authors have theoretically and experimentally investigated the extent to which homogeneous magnetic fields up to 7 Tesla reduce the spatial distance positrons travel before annihilation (positron range). Computer simulations of a noncoincident detector design using a Monte Carlo algorithm calculated the positron range as a function of positron energy and magnetic field strength. The simulation predicted improvements in resolution, defined as full-width at half-maximum (FWHM) of the line-spread function (LSF) for a magnetic field strength up to 7 Tesla: negligible for F-18, from 3.35 mm to 2.73 mm for Ga-68 and from 3.66 mm to 2.68 mm for Rb-82. Also a substantial noise suppression was observed, described by the full-width at tenth-maximum (FWTM) for higher positron energies. The experimental approach confirmed an improvement in resolution for Ga-68 from 3.54 mm at 0 Tesla to 2.99 mm FWHM at 4.5 Tesla and practically no improvement for F-18 (2.97 mm at 0 Tesla and 2.95 mm at 4.5 Tesla). It is concluded that the simulation model is appropriate and that a homogeneous static magnetic field of 4.5 Tesla reduces the range of high-energy positrons to an extent that may improve spatial resolution in positron emission tomography

  20. A Practical One-Pot Synthesis of Positron Emission Tomography (PET) Tracers via Nickel-Mediated Radiofluorination

    OpenAIRE

    Zlatopolskiy, Boris D; Zischler, Johannes; Urusova, Elizaveta A; Endepols, Heike; Kordys, Elena; Frauendorf, Holm; Mottaghy, Felix M; Neumaier, Bernd

    2015-01-01

    Invited for this months cover picture is the group of Professor Bernd Neumaier at the Institute of Radiochemistry and Experimental Molecular Imaging at the University Clinic of Cologne. The cover picture shows the differences in brain metabolism of a healthy young and a healthy old subject, as well as a patient suffering from Parkinsons disease (left to right) uncovered by 6-[18F]FDOPA-positron emission tomography (PET). Morbus Parkinson occurs when nerve cells that produce dopamine begin to ...

  1. F-18 fluoro-d-glucose positron emission tomography/computed tomography in a patient with corticobasal degeneration.

    Science.gov (United States)

    Marti, Alejandro

    2015-01-01

    Corticobasal degeneration is a rare neurodegenerative disorder that often eludes clinical diagnosis. The present case shows the F-18 fluoro-d-glucose positron emission tomography/computed tomography (PET/CT) of a 62-year-old man with a progressive movement disorder with asymmetric features. PET/CT examination showed a markedly right-brain hemispheric hypometabolism also involving basal ganglia. PMID:25829747

  2. 77 FR 21783 - Guidance on Media Fills for Validation of Aseptic Preparations for Positron Emission Tomography...

    Science.gov (United States)

    2012-04-11

    ... the same title was announced in the Federal Register on September 30, 2011 (76 FR 60847), and Docket... Preparations for Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug Administration, HHS... guidance entitled ``Media Fills for Validation of Aseptic Preparations for Positron Emission...

  3. 77 FR 71802 - Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Science.gov (United States)

    2012-12-04

    ... announced in the Federal Register on February 14, 2012 (77 FR 8262), and Docket No. FDA-2012-D- 0081 was... Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice... ``Investigational New Drug Applications for Positron Emission Tomography (PET) Drugs.'' The guidance is intended...

  4. Positron Emission Tomography (PET) and breast cancer in clinical practice

    Energy Technology Data Exchange (ETDEWEB)

    Lavayssiere, Robert [Centre d' Imagerie Paris-Nord, 1, avenue Charles Peguy, 95200 Sarcelles (France); Institut du Sein Henri Hartmann (ISHH), 1, rue des Dames Augustines, 92200 Neuilly sur Seine (France)], E-mail: cab.lav@wanadoo.fr; Cabee, Anne-Elizabeth [Centre d' Imagerie Paris-Nord, 1, avenue Charles Peguy, 95200 Sarcelles (France); Institut du Sein Henri Hartmann (ISHH), 1, rue des Dames Augustines, 92200 Neuilly sur Seine (France); Centre RMX, 80, avenue Felix Faure, 75105 Paris (France); Filmont, Jean-Emmanuel [Institut du Sein Henri Hartmann (ISHH), 1, rue des Dames Augustines, 92200 Neuilly sur Seine (France); American Hospital of Paris, Nuclear Medicine, 63, boulevard Victor Hugo - BP 109, 92202 Neuilly sur Seine Cedex (France)

    2009-01-15

    The landscape of oncologic practice has changed deeply during the past few years and there is now a need, through a multidisciplinary approach, for imaging to provide accurate evaluation of morphology and function and to guide treatment (Image Guided Therapy). Increasing emphasis has been put on Position Emission Tomography (PET) role in various cancers among clinicians and patients despite a general context of healthcare expenditure limitation. Positron Emission Tomography has currently a limited role in breast cancer, but also general radiologists and specialists should be aware of these indications, especially when staging aggressive cancers and looking for recurrence. Currently, the hybrid systems associating PET and Computed Tomography (CT) and in the same device [Rohren EM, Turkington TG, Coleman RE. Clinical applications of PET in oncology. Radiology 2004;231:305-32; Blodgett TM, Meltzer CM, Townsend DW. PET/CT: form and function. Radiology 2007;242:360-85; von Schulthess GK, Steinert HC, Hany TF. Integrated PET/CT: current applications and futures directions. Radiology 2006;238(2):405-22], or PET-CT, are more commonly used and the two techniques are adding their potentialities. Other techniques, MRI in particular, may also compete with PET in some instance and as far as ionizing radiations dose limitation is considered, some breast cancers becoming some form of a chronic disease. Breast cancer is a very complex, non-uniform, disease and molecular imaging at large may contribute to a better knowledge and to new drugs development. Ongoing research, Positron Emission Mammography (PEM) and new tracers, are likely to bring improvements in patient care [Kelloff GJ, Hoffman JM, Johnson B, et al. Progress and promise of FDG-PET Imaging for cancer patient management and oncologic drug development. Clin Cancer Res 2005;1(April (8)): 2005].

  5. Positron Emission Tomography (PET) and breast cancer in clinical practice

    International Nuclear Information System (INIS)

    The landscape of oncologic practice has changed deeply during the past few years and there is now a need, through a multidisciplinary approach, for imaging to provide accurate evaluation of morphology and function and to guide treatment (Image Guided Therapy). Increasing emphasis has been put on Position Emission Tomography (PET) role in various cancers among clinicians and patients despite a general context of healthcare expenditure limitation. Positron Emission Tomography has currently a limited role in breast cancer, but also general radiologists and specialists should be aware of these indications, especially when staging aggressive cancers and looking for recurrence. Currently, the hybrid systems associating PET and Computed Tomography (CT) and in the same device [Rohren EM, Turkington TG, Coleman RE. Clinical applications of PET in oncology. Radiology 2004;231:305-32; Blodgett TM, Meltzer CM, Townsend DW. PET/CT: form and function. Radiology 2007;242:360-85; von Schulthess GK, Steinert HC, Hany TF. Integrated PET/CT: current applications and futures directions. Radiology 2006;238(2):405-22], or PET-CT, are more commonly used and the two techniques are adding their potentialities. Other techniques, MRI in particular, may also compete with PET in some instance and as far as ionizing radiations dose limitation is considered, some breast cancers becoming some form of a chronic disease. Breast cancer is a very complex, non-uniform, disease and molecular imaging at large may contribute to a better knowledge and to new drugs development. Ongoing research, Positron Emission Mammography (PEM) and new tracers, are likely to bring improvements in patient care [Kelloff GJ, Hoffman JM, Johnson B, et al. Progress and promise of FDG-PET Imaging for cancer patient management and oncologic drug development. Clin Cancer Res 2005;1(April (8)): 2005

  6. Functional images analysis and visualization in positron emission tomography

    International Nuclear Information System (INIS)

    Essentially new information on the metabolism and pathophysiology is available since the recent past using techniques combining the use of positron emitters labelling radiopharmaceuticals, models correctly describing the process studied and system for the in vivo external detection of transverse section of the body. This method is currently called Positron Emission Tomography (PET). At the Service Hospitalier Frederic Joliot of the C.E.A. Departement of Biology, a system was developed for data analysis and colour-coded representation as a tool for functional interpretation. Indeed, the tomographic images, i.e. the radioactive concentration in the transverse section is often but the first step of the study, the actual goal being the regional distribution of a metabolic or physiologic parameter, itself derived from the former distribution by assumption of a model. Such a quantification assumes an accurate analysis of the factors involved in the obtention of the functional image, and the development of the software actually adapted to the clinician's needs. Special attention was given to the representation of graphs and images as a man-machine interface, a tool for model fitting and output of final results in pseudo-color scales adapted to the studied parameter

  7. Positron emission tomography with gamma camera in coincidence mode

    International Nuclear Information System (INIS)

    Positron emission tomography using F-18 FDG has been estbalished in clinical diagnostics with first indications especially in oncology. To install a conventional PET tomography (dedicated PET) is financially costly and restricted to PET examinations only. Increasing demand for PET diagnostics on one hand and restricted financial resources in the health system on the other hand led industry to develop SPECT cameras to be operated in coincidence mode (camera PET) in order to offer nuclear medicine physicians cost-effective devices for PET diagnostic. At the same time camera PET is inferior to conventional PET regarding sensitivity and detection-efficiency for 511 keV photons. Does camera-PET offer a reliable alternative to conventional PET? The first larger comparative studies are now available, so a first apraisal about the technical clinical performance of camera-PET can be done. (orig.)

  8. Timing performance comparison of digital methods in positron emission tomography

    International Nuclear Information System (INIS)

    Accurate timing information is essential in positron emission tomography (PET). Recent improvements in high speed electronics made digital methods more attractive to find alternative solutions to create a time mark for an event. Two new digital methods (mean PMT pulse model, MPPM, and median filtered zero crossing method, MFZCM) were introduced in this work and compared to traditional methods such as digital leading edge (LE) and digital constant fraction discrimination (CFD). In addition, the performances of all four digital methods were compared to analog based LE and CFD. The time resolution values for MPPM and MFZCM were measured below 300 ps at 1.6 GS/s and above that was similar to the analog based coincidence timing results. In addition, the two digital methods were insensitive to the changes in threshold setting that might give some improvement in system dead time.

  9. Magnet development for the BRF positron emission tomography accelerator

    International Nuclear Information System (INIS)

    A collaboration involving the Biomedical Research Foundation, Science Applications International Corporation, Fermi National Accelerator Laboratory, and the University of Washington is developing an accelerator for producing isotopes for Positron Emission Tomography (PET) scans. The Medium Energy Beam Transport (MEBT) section of this accelerator takes a small beam from a first RFQ acceleration device and matches it into a small 3D-acceptance at a second RFQ section. The beam transport system was designed to prevent beam losses due to emittance growth. The system includes two bending dipoles and seven quadrupoles of three different types. This report contains a brief description of the MEBT magnets and their electric, magnetic and thermal properties. The magnet measurements show that each of the magnets meets the system requirements

  10. Knowledge-based automated radiopharmaceutical manufacturing for Positron Emission Tomography

    International Nuclear Information System (INIS)

    This article describes the application of basic knowledge engineering principles to the design of automated synthesis equipment for radiopharmaceuticals used in Positron Emission Tomography (PET). Before discussing knowledge programming, an overview of the development of automated radiopharmaceutical synthesis systems for PET will be presented. Since knowledge systems will rely on information obtained from machine transducers, a discussion of the uses of sensory feedback in today's automated systems follows. Next, the operation of these automated systems is contrasted to radiotracer production carried out by chemists, and the rationale for and basic concepts of knowledge-based programming are explained. Finally, a prototype knowledge-based system supporting automated radiopharmaceutical manufacturing of 18FDG at Brookhaven National Laboratory (BNL) is described using 1stClass, a commercially available PC-based expert system shell

  11. Development of the LBNL positron emission mammography camera

    International Nuclear Information System (INIS)

    We present the construction status of the LBNL Positron Emission Mammography (PEM) camera, which utilizes a PET detector module with depth of interaction measurement consisting of 64 LSO crystals (3x3x30 mm3) coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PDs). The PMT provides an accurate timing pulse, the PDs identify the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction. We have completed construction of all 42 PEM detector modules. All data acquisition electronics have been completed, fully tested and loaded onto the gantry. We have demonstrated that all functions of the custom IC work using the production rigid-flex boards and data acquisition system. Preliminary detector module characterization and coincidence data have been taken using the production system, including initial images

  12. Guideline for performance evaluation of positron emission tomographs

    International Nuclear Information System (INIS)

    This supplement presents guideline for performance evaluation of positron emission tomographies (PET). The purpose of this guideline is to define measurement methods for evaluating both the performance of PET equipment and the accuracy of various data corrections in the clinical setting. The guideline has 8 items. The first four items, consisting of spatial dose distributions, scattering fraction, sensitivity, and counting loss and accidental coincidence counting, deals with the basic performance of PET equipment. The next three items, including image uniformity, accuracy of absorption and scattering correction, and characteristics of high counting rate (accuracy of counting loss corrections and S/N ratio), are designed to provide the quantitative evaluation of images reconstructed by various data corrections for absorption, scattering, counting loss, and others. The last item is partial volume effect (recovery coefficient), which is important for the quantitative analysis of PET images, with the aim of both the measurement method of partial volume effect and the definition of phantoms required. (N.K.)

  13. Positron Emission Tomography in the Differential Diagnosis of Parkinsonism

    Directory of Open Access Journals (Sweden)

    Juha O Rinne

    2009-10-01

    Full Text Available Positron emission tomography (PET studies on presynaptic dopaminergic function can reveal hypofunction in early Parkinson’s disease (PD which may help in the early diagnosis especially in patients with mild symptoms. This hypofunction can be detected with fluorodopa (reflecting mainly aromatic amino acid decarboxylase activity of nigrostriatal terminals or dopamine transporter ligands. These studies can also help to distinguish PD from essential tremor. However, investigations of presynaptic dopaminergic function are not useful in the differential diagnosis of parkinsonian syndromes. PET ligands, such as fluorodeoxyglucose (reflecting glucose metabolism and dopamine receptor ligands, reflecting striatal neuronal function are better in this respect. Cardiac sympathetic function studies represent a new and interesting approach to improve differential diagnosis of parkinsonian syndromes but more studies are needed in larger patient populations with longer follow-up to evaluate the usefulness of these investigations. Multitracer approach combining ligands reflecting different aspects of dopaminergic neurotransmission and other physiological function will increase differential diagnostic accuracy.

  14. Differential diagnosis of depression: relevance of positron emission tomography

    International Nuclear Information System (INIS)

    The proper differential diagnosis of depression is important. A large body of research supports the division of depressive illness into bipolar and unipolar subtypes with respect to demographics, genetics, treatment response, and neurochemical mechanisms. Optimal treatment is different for unipolar and bipolar depressions. Treating a patient with bipolar depression as one would a unipolar patient may precipitate a serious manic episode or possibly even permanent rapid cycling disorder. The clinical distinction between these disorders, while sometimes difficult, can often be achieved through an increased diagnostic suspicion concerning a personal or family history of mania. Positron emission tomography and the FDG method, which allow in vivo study of the glucose metabolic rates for discrete cerebral structures, provide new evidence that bipolar and unipolar depression are two different disorders

  15. Positron Emission Tomography: state of the art and future developments

    Science.gov (United States)

    Pizzichemi, M.

    2016-08-01

    Positron emission tomography (PET) plays a fundamental role in medical imaging, with a wide range of applications covering, among the others, oncology, neurology and cardiology. PET has undergone a steady technological evolution since its introduction in mid 20th century, from the development of 3D PET in the late 1980s, to the invention of PET/CT in the 1990s and more recently with the introduction of PET/MR scanners. The current research topics aiming to develop the next generation of PET scanners are summarized in this paper, focusing on the efforts to increase the sensitivity of the detectors, as long as improving their timing, spatial and energy resolutions, with the final goal of reducing the amount of radioactive dose received by the patients and the duration of the exams while improving at the same time the detectability of lesions.

  16. Positron emission tomography studies of central receptors in humans

    International Nuclear Information System (INIS)

    Central neurotransmitter systems and receptors are intimately involved in the mechanism of several neurologic and psychiatric disorders. One well-known example is the nigro-striatal dopaminergic system in akinesia of Parkinson's disease. Although neurotransmitter concentration and receptor function can be measured regionally post-mortem, positron tomography (PET) studies can be performed during life and therefore may provide insight into changes at early stages of the disease as well as follow-up data on, and pharmacological modification of, such changes. PET allows to monitor non-invasively the time-course of regional tissue tracer concentration following administration of a radioactive drug. If the latter is known to interact selectively with specific binding sites, it can be used to probe in vivo the regional distribution and affinity of the receptors involved. This principle was first pioneered using 3H or 14C-labeled ligands injected intravenously to laboratory animal, but necessitated brain tissue sampling for determination of regional radioactive concentration. The feasibility of the PET paradigm to characterize specific binding in vivo showed that trace amounts of 11C-labeled flunitrazepam could be displaced specifically from the baboon's brain by a therapeutic load of the unlabeled competitor Lorazepam, indicating that specific in vivo binding of the radioligand to the benzodiazepine (BZD) receptors has taken place

  17. Calculation of Positron Distribution in the Presence of a Uniform Magnetic Field for the Improvement of Positron Emission Tomography (PET) Imaging Using GEANT4 Toolkit

    OpenAIRE

    Mohsen Mashayekhi; Ali Asghar Mowlavi

    2015-01-01

    Introduction Range and diffusion of positron-emitting radiopharmaceuticals are important parameters for image resolution in positron emission tomography (PET). In this study, GEANT4 toolkit was applied to study positron diffusion in soft tissues with and without a magnetic field for six commonly used isotopes in PET imaging including 11C, 13N, 15O, 18F, 68Ga, and 82Rb. Materials and Methods GEANT4 toolkit was used to simulate the transport and interactions of positrons. Calculations ...

  18. Scintillation crystals for positron emission tomography having a non reflecting band

    International Nuclear Information System (INIS)

    This invention relates generally to positron emission tomography, a sub-field of the class of medical imaging techniques using ionizing radiation and image reconstruction techniques; and more particularly to devices which use an array of scintillation detectors to detect the annihilation radiation from positron disintegration and use this information to reconstruct an image of the distribution of positron emitting isotope within a body section. 6 figs

  19. Synthesis and in vivo studies of a specific monoamine oxidase B inhibitor: 5-[4-(benzyloxy)phenyl]-3-(2-cyanoethyl)-1,3,4-oxadiazol-[11C]-2(3H)-one. Biodistribution in the rat and positron emission tomography studies in the baboon brain

    International Nuclear Information System (INIS)

    We report the radiochemical synthesis of a specific MAO B inhibitor, namely 5-[4-(benzyloxy)phenyl]-3-(2-cyanoethyl)-1,3,4-oxadiazol-[11C]-2(3H)-one (2b) (in vitro IC50=4nM and selectivity over 71000 for MAO B), by cyclization of its hydrazide precursor 1 with [11C]phosgene. The reaction occurred within 2 min. The product obtained after HPLC purification, 2b, had a high specific activity (11.1-22.2 GBq/μmol), allowing its use in experiments as a radiotracer in vivo. Biodistribution of 2b in the CNS and in the peripheral organs of the rat, and positron emission tomography (PET) studies in the living baboon brain, pretreated or not with L-depdenyl (1 mg/kg, 1 h), an irreversible MAO B-specific inhibitor, were undertaken. The results showed a good uptake of 2b in all organs of the rate, with a rapid clearance from the blood (10 min). Metabolite analyses in plasma and in the diencephalon of the rat showed tha 2b was the only radioactive compound in brain structure whereas in plasma three other radioactive products appeared. PET experiments show that in the L-deprenyl-pretreated baboon brain, specific binding of 2b represents around 70% of total radioactivity, whereas in the blood and plasma the radioactivity cleared rapidly (15 min). (orig.)

  20. Synthesis and in vivo studies of a specific monoamine oxidase B inhibitor: 5-[4-(benzyloxy)phenyl]-3-(2-cyanoethyl)-1,3,4-oxadiazol-[{sup 11}C]-2(3H)-one. Biodistribution in the rat and positron emission tomography studies in the baboon brain

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, S. [Service Hospitalier Frederic Joliot, DRIPP, CEA, 91 - Orsay (France)]|[Lab. de Chimie Organique Medicale, Unite de Recherche Chimie et Pharmacologie, Faculte de Medecine Xavier Bichat, Paris-7 Univ., 75 (France); Fuseau, C. [Service Hospitalier Frederic Joliot, DRIPP, CEA, 91 - Orsay (France); Schmid, L. [Service Hospitalier Frederic Joliot, CNRS URA, CEA, 91 - Orsay (France); Milcent, R. [Lab. de Chimie Organique Medicale, Unite de Recherche Chimie et Pharmacologie, Faculte de Medecine Xavier Bichat, Paris-7 Univ., 75 (France); Crouzel, C. [Service Hospitalier Frederic Joliot, DRIPP, CEA, 91 - Orsay (France)

    1996-02-01

    We report the radiochemical synthesis of a specific MAO B inhibitor, namely 5-[4-(benzyloxy)phenyl]-3-(2-cyanoethyl)-1,3,4-oxadiazol-[{sup 11}C]-2(3H)-one (2b) (in vitro IC{sub 50}=4nM and selectivity over 71000 for MAO B), by cyclization of its hydrazide precursor 1 with [{sup 11}C]phosgene. The reaction occurred within 2 min. The product obtained after HPLC purification, 2b, had a high specific activity (11.1-22.2 GBq/{mu}mol), allowing its use in experiments as a radiotracer in vivo. Biodistribution of 2b in the CNS and in the peripheral organs of the rat, and positron emission tomography (PET) studies in the living baboon brain, pretreated or not with L-depdenyl (1 mg/kg, 1 h), an irreversible MAO B-specific inhibitor, were undertaken. The results showed a good uptake of 2b in all organs of the rate, with a rapid clearance from the blood (10 min). Metabolite analyses in plasma and in the diencephalon of the rat showed tha 2b was the only radioactive compound in brain structure whereas in plasma three other radioactive products appeared. PET experiments show that in the L-deprenyl-pretreated baboon brain, specific binding of 2b represents around 70% of total radioactivity, whereas in the blood and plasma the radioactivity cleared rapidly (15 min). (orig.)

  1. Spatial registration of echocardiographic and positron emission tomographic heart studies

    International Nuclear Information System (INIS)

    A method has been developed to match corresponding heart regions from functional echocardiographic (Echo) and metabolic fluorine-18-fluoro-2-deoxy-D-glucose ([18F]FDG) positron emission tomography (PET) studies in individual patients. Echo and PET images are spatially correlated by determining homologous anatomical landmarks (the two papillary muscles and the inferior junction of the right ventricle), identifiable in images obtained by both acquisition modalities. Echo-PET image registration is first performed in the plane identified by the three landmarks, using a rigid rotate-translate scale model. The registration parameters are then used to transform the whole PET volume. This allows a consistent Echo-PET regional analysis, according to a segmental subdivision of the heart. The technique was tested on patients. The overlay of Echo and PET registered images proved the reliability of realignment of the three markers and a good spatial correlation of myocardial walls. This approach to image registration could be applied to other acquisition modalities (such as magnetic resonance imaging and single-photon emission tomography), provided that the three anatomical landmarks are visualized. (orig.)

  2. Dynamic Positron Emission Tomography Imaging of Renal Clearable Gold Nanoparticles.

    Science.gov (United States)

    Chen, Feng; Goel, Shreya; Hernandez, Reinier; Graves, Stephen A; Shi, Sixiang; Nickles, Robert J; Cai, Weibo

    2016-05-01

    Optical imaging has been the primary imaging modality for nearly all of the renal clearable nanoparticles since 2007. Due to the tissue depth penetration limitation, providing accurate organ kinetics non-invasively has long been a huge challenge. Although a more quantitative imaging technique has been developed by labeling nanoparticles with single-photon emission computed tomography (SPECT) isotopes, the low temporal resolution of SPECT still limits its potential for visualizing the rapid dynamic process of renal clearable nanoparticles in vivo. The dynamic positron emission tomography (PET) imaging of renal clearable gold (Au) nanoparticles by labeling them with copper-64 ((64) Cu) to form (64) Cu-NOTA-Au-GSH is reported. Systematic nanoparticle synthesis and characterizations are performed to demonstrate the efficient renal clearance of as-prepared nanoparticles. A rapid renal clearance of (64) Cu-NOTA-Au-GSH is observed (>75%ID at 24 h post-injection) with its elimination half-life calculated to be less than 6 min, over 130 times shorter than previously reported similar nanoparticles. Dynamic PET imaging not only addresses the current challenges in accurately and non-invasively acquiring the organ kinetics, but also potentially provides a highly useful tool for studying renal clearance mechanism of other ultra-small nanoparticles, as well as the diagnosis of kidney diseases in the near future. PMID:27062146

  3. Correlated electron-positron emission in heavy-ion collisions

    International Nuclear Information System (INIS)

    A group of narrow electron-positron sum-energy lines with similar mean energies around 610, 750 and 810 keV has been observed with the EPOS spectrometer in both collision systems 238U + 232Th and 238U + 181Ta studied so far at the UNILAC heavy ion accelerator of GSI, Darmstadt. The intensities of the three lines vary with the beam-energy, the variation being most clearly observed for the 748-keV line in 238U + 181Ta. On the basis of our present understanding Internal Pair Conversion in a collision product at rest or in flight as well as coincident lepton emission during the quasiatomic phase of the collision can be excluded as the origin. The very narrow widths of the sum-energy lines as compared to the widths of the associated broad structure in the difference spectrum of the lepton energies seem to argue for a mutual cancellation of kinematical shifts. Such correlation is expected for two leptons emitted back-to-back in a two-body decay of objects being at rest in the heavy-ion c.m. frame. This speculative hypothesis is confronted with the actual dependence of the lines on the individual lepton energy and the lepton emission angle, as well as on the opening angle of the pair. In fact, the back-to-back decay could not be proved to be a general feature of these lines. (orig.)

  4. Positron emission tomography in aging and dementia: effect of cerebral atrophy

    International Nuclear Information System (INIS)

    The spatial resolution of current positron emission tomography (PET) scanners does not allow a distinction between cerebrospinal fluid (CSF) containing spaces and contiguous brain tissue. Data analysis strategies which therefore purport to quantify cerebral metabolism per unit mass brain tissue are in fact measuring a value which may be artifactually reduced due to contamination by CSF. We studied cerebral glucose metabolism (CMRglc) in 17 healthy elderly individuals and 24 patients with Alzheimer's dementia using [18F]fluorodeoxyglucose and PET. All subjects underwent x-ray computed tomography (XCT) scanning at the time of their PET study. The XCT scans were analyzed volumetrically, in order to determine relative areas for ventricles, sulci, and brain tissue. Global CMRglc was calculated before and after correction for contamination by CSF (cerebral atrophy). A greater increase in global CMRglc after atrophy correction was seen in demented individuals compared with elderly controls (16.9% versus 9.0%, p less than 0.0005). Additional preliminary data suggest that volumetric analysis of proton-NMR images may prove superior to analysis of XCT data in quantifying the degree of atrophy. Appropriate corrections for atrophy should be employed if current PET scanners are to accurately measure actual brain tissue metabolism in various pathologic states

  5. Development of radiotracers for imaging NR2B subtype NMDA receptors with positron emission tomography

    International Nuclear Information System (INIS)

    The aim of this thesis was to develop new radioactive tracers for imaging NR2B subtype NMDA receptors with positron emission tomography. Several compounds including 4-(4-fluoro-benzyl)piperidine and presenting interesting in vivo biological properties were the object of a labelling with a positrons emitter atom (11C or 18F)

  6. Positron emission tomography in human hemispheric infarction: a study with 150 continuous inhalation technique

    International Nuclear Information System (INIS)

    Non-invasive tomographic imaging of cerebral blood flow and oxygen metabolism has now become possible with the 15O continuous inhalation technique coupled with positron emission tomography (PET). We have for the first time applied this procedure in a large scale study of human hemispheric infarction. From this study, it may be concluded that: various hitherto undescribed patterns of disturbances in the perfusion/metabolism couple that occur in cerebral infarction have been documented by PET imaging of CBF and EO2. The EO2 appears as an important physiological parameter in the study of recent cerebral infarction, and specific patterns of the CBF/EO2 relationship are now emerging that may have important pathophysiologic, prognostic and therapeutic implications. Despite some limitations, the non invasive 15O inhalation technique has a number of major specific advantages that make it particularly suited for the study of ischemic brain disorders

  7. Marked reduction of cerebral oxygen metabolism in patients with advanced cirrhosis; A positron emission tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Kawatoko, Toshiharu; Murai, Koichiro; Ibayashi, Setsurou; Tsuji, Hiroshi; Nomiyama, Kensuke; Sadoshima, Seizo; Eujishima, Masatoshi; Kuwabara, Yasuo; Ichiya, Yuichi (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

    1992-01-01

    Regional cerebral blood flow (rCBF), cerebral metabolic rate of oxygen (rCMRO{sub 2}), and oxygen extraction fraction (rOEF) were measured using positron emission tomography (PET) in four patients with cirrhosis (two males and two females, aged 57 to 69 years) in comparison with those in five age matched controls with previous transient global amnesia. PET studies were carried out when the patients were fully alert and oriented after the episodes of encephalopathy. In the patients, rCBF tended to be lower, while rCMRO{sub 2} was significantly lowered in almost all hemisphere cortices, more markedly in the frontal cortex. Our results suggest that the brain oxygen metabolism is diffusely impaired in patients with advanced cirrhosis, and the frontal cortex seems to be more susceptible to the systemic metabolic derangements induced by chronic liver disease. (author).

  8. Greater left cerebral hemispheric metabolism in bulimia assessed by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.C.; Hagman, J.; Buchsbaum, M.S.; Blinder, B.; Derrfler, M.; Tai, W.Y.; Hazlett, E.; Sicotte, N. (Univ. of California, Irvine (USA))

    1990-03-01

    Eight women with bulimia and eight age- and sex-matched normal control subjects were studied with positron emission tomography using (18F)-fluorodeoxyglucose (FDG) as a tracer of brain metabolic rate. Subjects performed a visual vigilance task during FDG uptake. In control subjects, the metabolic rate was higher in the right hemisphere than in the left, but patients with bulimia did not have this normal asymmetry. Lower metabolic rates in the basal ganglia, found in studies of depressed subjects, and higher rates in the basal ganglia, reported in a study of anorexia nervosa, were not found. This is consistent with the suggestion that bulimia is a diagnostic grouping distinct from these disorders.

  9. Regional cerebral glucose metabolic rate in human sleep assessed by positron emission tomography

    International Nuclear Information System (INIS)

    The cerebral metabolic rate of glucose was measured during nighttime sleep in 36 normal volunteers using positron emission tomography and fluorine-18-labeled 2-deoxyglucose (FDG). In comparison to waking controls, subjects given FDG during non-rapid eye movement (NREM) sleep showed about a 23% reduction in metabolic rate across the entire brain. This decrease was greater for the frontal than temporal or occipital lobes, and greater for basal ganglia and thalamus than cortex. Subjects in rapid eye movement (REM) sleep tended to have higher cortical metabolic rates than walking subjects. The cingulate gyrus was the only cortical structure to show a significant increase in glucose metabolic rate in REM sleep in comparison to waking. The basal ganglia were relatively more active on the right in REM sleep and symmetrical in NREM sleep

  10. Regional cerebral glucose metabolic rate in human sleep assessed by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Buchsbaum, M.S.; Wu, J.; Hazlett, E.; Sicotte, N.; Bunney, W.E. Jr. (Univ. of California, Irvine (USA)); Gillin, J.C. (Univ. of California, San Diego (USA))

    1989-01-01

    The cerebral metabolic rate of glucose was measured during nighttime sleep in 36 normal volunteers using positron emission tomography and fluorine-18-labeled 2-deoxyglucose (FDG). In comparison to waking controls, subjects given FDG during non-rapid eye movement (NREM) sleep showed about a 23% reduction in metabolic rate across the entire brain. This decrease was greater for the frontal than temporal or occipital lobes, and greater for basal ganglia and thalamus than cortex. Subjects in rapid eye movement (REM) sleep tended to have higher cortical metabolic rates than walking subjects. The cingulate gyrus was the only cortical structure to show a significant increase in glucose metabolic rate in REM sleep in comparison to waking. The basal ganglia were relatively more active on the right in REM sleep and symmetrical in NREM sleep.

  11. Positron Emission Tomography with Three-Dimensional Reconstruction

    International Nuclear Information System (INIS)

    The development of two different low-cost scanners for positron emission tomography (PET) based on 3D acquisition are presented. The first scanner consists of two rotating scintillation cameras, and produces quantitative images, which have shown to be clinically useful. The second one is a system with two opposed sets of detectors, based on the limited angle tomography principle, dedicated for mammographic studies. The development of low-cost PET scanners can increase the clinical impact of PET, which is an expensive modality, only available at a few centres world-wide and mainly used as a research tool. A 3D reconstruction method was developed that utilizes all the available data. The size of the data-sets is considerably reduced, using the single-slice rebinning approximation. The 3D reconstruction is divided into 1D axial deconvolution and 2D transaxial reconstruction, which makes it relatively fast. This method was developed for the rotating scanner, but was also implemented for multi-ring scanners with and without inter plane septa. An iterative 3D reconstruction method was developed for the limited angle scanner, based on the new concept of 'mobile pixels', which reduces the finite pixel errors and leads to an improved signal to noise ratio. 100 refs

  12. Characterization of time resolved photodetector systems for Positron Emission Tomography

    CERN Document Server

    Powolny, François

    The main topic of this work is the study of detector systems composed of a scintillator, a photodetector and readout electronics, for Positron Emission Tomography (PET). In particular, the timing properties of such detector systems are studied. The first idea is to take advantage of the good timing properties of the NINO chip, which is a fast preamplifier-discriminator developed for the ALICE Time of flight detector at CERN. This chip uses a time over threshold technique that is to be applied for the first time in medical imaging applications. A unique feature of this technique is that it delivers both timing and energy information with a single digital pulse, the time stamp with the rising edge and the energy from the pulse width. This entails substantial simplification of the entire readout architecture of a tomograph. The scintillator chosen in the detector system is LSO. Crystals of 2x2x10mm3 were used. For the photodetector, APDs were first used, and were then replaced by SiPMs to make use of their highe...

  13. Silicon as an unconventional detector in positron emission tomography

    Science.gov (United States)

    Clinthorne, Neal; Brzezinski, Karol; Chesi, Enrico; Cochran, Eric; Grkovski, Milan; Grošičar, Borut; Honscheid, Klaus; Huh, Sam; Kagan, Harris; Lacasta, Carlos; Linhart, Vladimir; Mikuž, Marko; Smith, D. Shane; Stankova, Vera; Studen, Andrej; Weilhammer, Peter; Žontar, Dejan

    2013-01-01

    Positron emission tomography (PET) is a widely used technique in medical imaging and in studying small animal models of human disease. In the conventional approach, the 511 keV annihilation photons emitted from a patient or small animal are detected by a ring of scintillators such as LYSO read out by arrays of photodetectors. Although this has been successful in achieving ˜5 mm FWHM spatial resolution in human studies and ˜1 mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches including the potential for high intrinsic spatial resolution in 3D. To evaluate silicon in a variety of PET "magnifying glass" configurations, an instrument was constructed that consists of an outer partial-ring of PET scintillation detectors into which various arrangements of silicon detectors are inserted to emulate dual-ring or imaging probe geometries. Measurements using the test instrument demonstrated the capability of clearly resolving point sources of 22Na having a 1.5 mm center-to-center spacing as well as the 1.2 mm rods of a 18F-filled resolution phantom. Although many challenges remain, silicon has potential to become the PET detector of choice when spatial resolution is the primary consideration.

  14. The natural history of misery perfusion in positron emission tomography

    International Nuclear Information System (INIS)

    This report reviews the natural courses of misery perfusion in 5 patients with atherosclerotic cerebrovascular occlusion diseases. Cases 1 showed partial improvement and Case 2 showed deterioration of misery perfusion on positron emission tomography (PET). These 2 patients did not show any clinical changes during the follow-up periods. Case 3 showed remarkable improvement of misery perfusion during the 2-year follow-ups, but his neurological condition worsened. The EC-IC bypass improved both in PET and clinical symptoms. Case 4 had a stroke at the region of misery perfusion in PET. Case 5 had a lacunar infarction 2 years after the EC-IC bypass on the opposite side. PET taken one month before the stroke did not show any signs of hypoperfusion in the area of the lacunar infarction. Misery perfusion seems not to be a static but a dynamic condition that can develop into cerebral infarction by some hemodynamic stresses. Cerebral cortical or lobar infarction may occur in the region of severe misery perfusion. EC-IC bypass may prevent impending infarction of the cerebral cortex by improving the regional cerebral blood flow. However, EC-CI bypass will not prevent the lacunar infarction of the basal ganglia or internal capsule. (author)

  15. European health telematics networks for positron emission tomography

    International Nuclear Information System (INIS)

    A pilot network of positron emission tomography centers across Europe has been setup employing telemedicine services. The primary aim is to bring all PET centers in Europe (and beyond) closer, by integrating advanced medical imaging technology and health telematics networks applications into a single, easy to operate health telematics platform, which allows secure transmission of medical data via a variety of telecommunications channels and fosters the cooperation between professionals in the field. The platform runs on PCs with Windows 2000/XP and incorporates advanced techniques for image visualization, analysis and fusion. The communication between two connected workstations is based on a TCP/IP connection secured by secure socket layers and virtual private network or jabber protocols. A teleconsultation can be online (with both physicians physically present) or offline (via transmission of messages which contain image data and other information). An interface sharing protocol enables online teleconsultations even over low bandwidth connections. This initiative promotes the cooperation and improved communication between nuclear medicine professionals, offering options for second opinion and training. It permits physicians to remotely consult patient data, even if they are away from the physical examination site

  16. Clinical application of positron emission tomography imaging in urologic tumors

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is an advanced noninvasive molecular imaging modality that is being investigated for use in the differentiation, diagnosis, and guiding therapy ora variety of cancer types. FDG PET has the unique clinical value in the differentiation, diagnosis, and monitoring therapy of prostate, such as bladder, renal, and testicle cancer. However, high false-positive and false-negative findings are observed in the detection of these tumors with FDG PET. 11C-Choline (CH) and 11C-acetate (AC) can overcome the pitfall of FDG, and appear to be more successful than FGD in imaging prostate cancer and bladder cancer. The short half-life of 11C prevents the widespread use of CH and AC and 18F-fluorocholine (FCH) and 18F-fluoroacetate (FAC) seem to be potential tracers. Potential clinical value of the new PET tracers, such as 3'-deoxy-3'-18F-fluorothymidine (FLT), 18F-fluorodihydrotestosterone (FDHT), and 9-(4-18F-3-hydroxymethylbutyl)-guanine(18F-FHBG) in the detection of urologic tumors, can deserve further study. (authors)

  17. Diagnosis of intrahepatic cholangiocarcinoma with positron emission tomography

    International Nuclear Information System (INIS)

    Diagnosis of intrahepatic cholangiocarcinoma (IC) by positron emission tomography (PET) has been scarcely reported and this paper reviews authors' experience of PET diagnosis of IC with [18F]deoxy-glucose (FDG). Subjects are 20 cases with IC who received FDG-PET diagnosis for evaluating the disease progression and 16 cases with suspicious recurrent IC. PET was done with Advance NXi machine (GE Medical System) 60 min after intravenous 200-250 MBq of FDG. Compared were images by PET and CT. For the IC, diagnostic sensitivities by CT and PET were found to be 95-100% and for metastatic lymph nodes, the sensitivity, specificity and overall accuracy of PET were 38, 100 and 74%, respectively, whereas those of CT, 75, 73 and 74%. For recurrence, those of PET were 77, 67 and 75%. In conclusion, PET images have a compensatory role for CT images, especially for lymphatic metastasis with higher specificity and for recurrence with higher overall accuracy. (R.T.)

  18. Predicting count loss in modern positron-emission tomography systems

    International Nuclear Information System (INIS)

    The purpose of the data-acquisition electronics for any positron-emission tomography (PET) system is to detect and digitally encode annihilation events as they occur. Individual elements of the electronics are placed in parallel or cascade to organize the event information for subsequent processing. Each element is parameterized with a count loss L which is the fraction of events lost due to dead time (encoding delays, etc.) or data overflow in queueing circuits. This is an important parameter because the sensitivity of the tomograph in proportional to (1-L). The authors have categorized processing elements according to five device types. For each type, they find an expression for count loss. Some mathematical models that have appeared in the literature are applicable. These are extended here to include other devices, such as bank encoders and time-to-digital converters (TDC), with coincidence time resolving circuitry. Because some PET systems will have devices that do not fall into these categories, the authors show the derivations of the loss expressions so that one could easily extend their models with parallel derivations for other device types. In addition to PET systems, one should also be able to apply their results to other types of instruments which count random events. Although they concentrate mainly on count loss, they also briefly discuss the evaluation of other metrics of counting efficiency, which are the fraction of miscoded events and the fraction of ''random coincidence'' events

  19. European health telematics networks for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kontaxakis, George [Universidad Politecnica de Madrid, ETSI Telecomunicacion, Madrid 28040 (Spain)]. E-mail: g.kontaxakis@upm.es; Pozo, Miguel Angel [Centro PET Complutense, Madrid 28040 (Spain); Universidad Complutense de Madrid, Instituto Pluridisciplinar, Madrid 28040 (Spain); Ohl, Roland [MedCom Gesellschaft fuer medizinische Bildverarbeitung mbH, Darmstadt 64283 (Germany); Visvikis, Dimitris [U650 INSERM, Lab. du Traitement de L' Information Medicale, University of Brest Occidentale, CHU Morvan, Brest 29609 (France); Sachpazidis, Ilias [Fraunhofer Institute for Computer Graphics, Darmstadt 64283 (Germany); Ortega, Fernando [Fundacion Instituto Valenciano de Oncologia, Valencia 46009 (Spain); Guerra, Pedro [Universidad Politecnica de Madrid, ETSI Telecomunicacion, Madrid 28040 (Spain); Cheze-Le Rest, Catherine [Dept. Medicine Nucleaire, CHU Morvan, Brest 29609 (France); Selby, Peter [MedCom Gesellschaft fuer medizinische Bildverarbeitung mbH, Darmstadt 64283 (Germany); Pan, Leyun [German Cancer Research Centre, Clinical Cooperation Unit Nuclear Medicine, Heidelberg 69120 (Germany); Diaz, Javier [Fundacion Instituto Valenciano de Oncologia, Valencia 46009 (Spain); Dimitrakopoulou-Strauss, Antonia [German Cancer Research Centre, Clinical Cooperation Unit Nuclear Medicine, Heidelberg 69120 (Germany); Santos, Andres [Universidad Politecnica de Madrid, ETSI Telecomunicacion, Madrid 28040 (Spain); Strauss, Ludwig [German Cancer Research Centre, Clinical Cooperation Unit Nuclear Medicine, Heidelberg 69120 (Germany); Sakas, Georgios [MedCom Gesellschaft fuer medizinische Bildverarbeitung mbH, Darmstadt 64283 (Germany); Fraunhofer Institute for Computer Graphics, Darmstadt 64283 (Germany)

    2006-12-20

    A pilot network of positron emission tomography centers across Europe has been setup employing telemedicine services. The primary aim is to bring all PET centers in Europe (and beyond) closer, by integrating advanced medical imaging technology and health telematics networks applications into a single, easy to operate health telematics platform, which allows secure transmission of medical data via a variety of telecommunications channels and fosters the cooperation between professionals in the field. The platform runs on PCs with Windows 2000/XP and incorporates advanced techniques for image visualization, analysis and fusion. The communication between two connected workstations is based on a TCP/IP connection secured by secure socket layers and virtual private network or jabber protocols. A teleconsultation can be online (with both physicians physically present) or offline (via transmission of messages which contain image data and other information). An interface sharing protocol enables online teleconsultations even over low bandwidth connections. This initiative promotes the cooperation and improved communication between nuclear medicine professionals, offering options for second opinion and training. It permits physicians to remotely consult patient data, even if they are away from the physical examination site.

  20. Positron emission tomography scans on kanji and kana

    International Nuclear Information System (INIS)

    We reanalyzed our positron emission tomography (PET) study on reading of Japanese kanji (morphogram) words, kana (phonogram) words and kana nonwords, using Statistical Parametric Mapping (SPM). The basal occipital and occipito-temporal areas were activated in common, among which activity was most pronounced in the fusiform/inferior temporal gyri with kanji and in the inferior occipital gyrus with kana. The results were consistent with the clinical observations that damage to the posterior inferior temporal cortex including the fusiform/inferior temporal gyri causes alexia with agraphia for kanji, whereas damage to the posterior occipital area including the inferior occipital gyrus causes pure alexia for kana. Bases on the present results and the lesion studies, a dual-route hypothesis that modifies Iwata's model of reading about the Japanese language was proposed. That is, the middle occipital gyrus, deep perisylvian temporoparietal cortex and posterior temporal gyrus constitute a dorsal route for reading and process phonology for words, whereas the inferior occipital, fusiform and posterior inferior temporal gyri constitute a ventral route for reading and process orthography and lexico-semantics for words. The ventral route may gain dominance in reading, according as a word is repeatedly presented. (author)

  1. Characterization of nontransmural myocardial infarction by positron-emission tomography

    International Nuclear Information System (INIS)

    The present study was performed to determine whether positron emission tomography (PET) performed after i.v. 11C-palmitate permits detection and characterization of nontransmural myocardial infarction. PET was performed after the i.v. injection of 11C-palmitate in 10 normal subjects, 24 patients with initial nontransmural myocardial infarction (defined electrocardiographically), and 22 patients with transmural infarction. Depressed accumulation of 11C-palmitate was detected with sagittal, coronal and transverse reconstructions, and quantified based on 14 contiguous transaxial reconstructions. Defects with homogeneously intense depression of accumulation of tracer were detected in all 22 patients with transmural infarction (100%). Abnormalities of the distribution of 11C-palmitate in the myocardium were detected in 23 patients with nontransmural infarction (96%). Thallium scintigrams were abnormal in only 11 of 18 patients with nontransmural infarction (61%). Tomographically estimated infarct size was greater among patients with transmural infarction (50.4 +/- 7.8 PET-g-Eq/m2 [+/- SEM SEM]) compared with those with nontransmural infarction (19 +/- 4 PET-g-Eq, p less than 0.01). Residual accumulation of 11C-palmitate within regions of infarction was more intensely depressed among patients with transmural compared to nontransmural infarction (33 +/- 1 vs 39 +/- 1% maximal myocardial radioactivity, p less than 0.01). Thus, PET and metabolic imaging with 11C-palmitate is a sensitive means of detecting, quantifying and characterizing nontransmural and transmural myocardial infarction

  2. Positron emission tomography in degenerative disorders of the dopaminergic system

    International Nuclear Information System (INIS)

    21 patients who had Parkinson's disease (PD), PD plus dementia of Alzheimer type (PDAT) or progressive supranuclear palsy (PSP), were studied with positron emission tomography (PET) using (18F)-2-fluoro-2-deoxy-D-glucose (FDG). In one patient with strictly unilateral PD side differences in striatal dopa uptake were studied with 6-(18F)fluoro-L-dopa (F-dopa). In patients with PD PET with FDG did not show any significant change in regional cerebral metabolic rates for glucose (rCMR(Glu)). In PDAT glucose metabolism was generally reduced, the most severe decrease was found in parietal cortex. The matebolic pattern was similar to that typically found in patients with Alzheimer's disease (AD). In the patients with strictly unilateral PD rCMR(Glu) was normal, F-dopa PET, however, revealed a distinct reduction of dopa uptake in the contralateral putamen. In PSP glucose metabolism was significantly decreased in subcortical regions (caudatum, putamen and brainstem) and in frontal cortex. Thus PET demonstrated a clear difference of metabolic pattern between PDAT and PSP

  3. Photon time-of-flight-assisted positron emission tomography

    International Nuclear Information System (INIS)

    In positron emission tomography (PET), the annihilation radiation is usually detected as a coincidence occurrence that localizes the position of the annihilation event to a straight line joining the detectors. The measure of the difference between the time of flight (TOF) of the annihilation photons between their inception and their detection permits the localization of the position of the annihilation event along the coincidence line. The incorporation of TOF information into the PET reconstruction process improves the signal-to-noise ratio in the image obtained. The utilization of scintillation detectors utilizing cesium fluoride scintillators, fast photomultiplier tubes, and fast timing circuits allows sub-nanosecond coincidence timing resolution needed for the effective use of TOF in PET. Mathematical considerations and pilot experiments show that with state-of-the-art electronic components and through the application of proper reconstruction algorithms, the combination of TOF and PET positional data improves severalfold the signal-to-noise ratio with respect to conventional PET image reconstruction at the cost of increasing the amount of data to be processed. The construction of a TOF-assisted PET device is within the capability of state-of-the-art technology

  4. European health telematics networks for positron emission tomography

    Science.gov (United States)

    Kontaxakis, George; Pozo, Miguel Angel; Ohl, Roland; Visvikis, Dimitris; Sachpazidis, Ilias; Ortega, Fernando; Guerra, Pedro; Cheze-Le Rest, Catherine; Selby, Peter; Pan, Leyun; Diaz, Javier; Dimitrakopoulou-Strauss, Antonia; Santos, Andres; Strauss, Ludwig; Sakas, Georgios

    2006-12-01

    A pilot network of positron emission tomography centers across Europe has been setup employing telemedicine services. The primary aim is to bring all PET centers in Europe (and beyond) closer, by integrating advanced medical imaging technology and health telematics networks applications into a single, easy to operate health telematics platform, which allows secure transmission of medical data via a variety of telecommunications channels and fosters the cooperation between professionals in the field. The platform runs on PCs with Windows 2000/XP and incorporates advanced techniques for image visualization, analysis and fusion. The communication between two connected workstations is based on a TCP/IP connection secured by secure socket layers and virtual private network or jabber protocols. A teleconsultation can be online (with both physicians physically present) or offline (via transmission of messages which contain image data and other information). An interface sharing protocol enables online teleconsultations even over low bandwidth connections. This initiative promotes the cooperation and improved communication between nuclear medicine professionals, offering options for second opinion and training. It permits physicians to remotely consult patient data, even if they are away from the physical examination site.

  5. Positron emission tomography scans on kanji and kana

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Yasuhisa [Mitsui Memorial Hospital, Tokyo (Japan)

    2002-12-01

    We reanalyzed our positron emission tomography (PET) study on reading of Japanese kanji (morphogram) words, kana (phonogram) words and kana nonwords, using Statistical Parametric Mapping (SPM). The basal occipital and occipito-temporal areas were activated in common, among which activity was most pronounced in the fusiform/inferior temporal gyri with kanji and in the inferior occipital gyrus with kana. The results were consistent with the clinical observations that damage to the posterior inferior temporal cortex including the fusiform/inferior temporal gyri causes alexia with agraphia for kanji, whereas damage to the posterior occipital area including the inferior occipital gyrus causes pure alexia for kana. Bases on the present results and the lesion studies, a dual-route hypothesis that modifies Iwata's model of reading about the Japanese language was proposed. That is, the middle occipital gyrus, deep perisylvian temporoparietal cortex and posterior temporal gyrus constitute a dorsal route for reading and process phonology for words, whereas the inferior occipital, fusiform and posterior inferior temporal gyri constitute a ventral route for reading and process orthography and lexico-semantics for words. The ventral route may gain dominance in reading, according as a word is repeatedly presented. (author)

  6. Fluorodeoxyglucose positron emission tomography in pancreatic cancer: an unsolved problem

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takashi [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Fukatsu, Hiroshi [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Ito, Kengo; Tadokoro, Masanori [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Ota, Toyohiro [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Ikeda, Mitsuru [Dept. of Medical Information and Medical Records, Nagoya Univ. School of Medicine (Japan); Isomura, Takayuki [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Ito, Shigeki [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Nishino, Masanari [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan); Ishigaki, Takeo [Dept. of Radiology, Nagoya Univ. School of Medicine (Japan)

    1995-01-01

    The aim of this study was to examine the significance and problems of 2-[fluorine-18]-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in diagnosing pancreatic cancer and mass-forming pancreatitis (MFP). PET, X-ray computed tomography (CT) and magnetic resonance (MR) imaging were performed in 15 patients with pancreatic cancer and nine patients with MFP. The areas of the PET scan were determined according to the markers drawn on the patients at CT or MR imaging. Regions of interests (ROIs) were placed by reference to the CT or MR images corresponding to the PET images. Tissue metabolism was evaluated by the differential absorption ratio (DAR) at 50 min after intravenous injection of FDG [DAR = tissue tracer concentration/(injected dose/body weight)]. The DAR value differed significantly in pancreatic cancer (mean{+-}SD, 4.64{+-}1.94) and MFP (mean{+-}SD, 2.84{+-}2.22) (P<0.05). In one false-negative case (mucinous adenocarcinoma), the tumour contained a small number of malignant cells. In one false-positive case, lymphocytes accumulated densely in the mass in the pancreatic head. Further studies are necessary to investigate the histopathological characteristics (especially the cellularity) and other factors affecting the FDG DAR on PET images. (orig.)

  7. Cerebral perfusion reserve indexes determined by fluoromethane positron emission scanning

    International Nuclear Information System (INIS)

    An index of cerebral perfusion reserve (RES%), defined as the percent change of regional cerebral blood flow over baseline per mm Hg of end-tidal CO2 tension, was determined for each middle cerebral artery (MCA) territory in patients with unilateral carotid distribution transient ischemic attacks or minor cerebrovascular accidents and was compared with that of age-matched, neurologically normal volunteers. Vasodilator responses to induced hypercapnia were tested during inhalation of 5% CO2 in 95% O2 while regional cerebral blood flow was measured by fluoromethane inhalation positron emission tomography. Mean RES% for 24 normal MCA territories was 5.2 +/- 0.8%. Mean RES% for 15 patient nonischemic MCA territories was 3.8 +/- 1.3% and for 15 ischemic MCA territories was 2.8 +/- 1.9% (both p less than 0.001). Individual RES% values and symmetry ratios between ischemic and nonischemic regions were also determined and compared with angiographic data. Areas of diminished, asymmetric, or paradoxical (two patients) CO2 reactivity appear to correspond to areas of compensatory vasodilation. We found this technique to be a safe and reproducible method for defining and recording localized areas of cerebral tissue at apparent risk for hemodynamically related damage

  8. Positron emission tomography in degenerative disorders of the dopaminergic system

    International Nuclear Information System (INIS)

    21 patients who had Parkinson's disease (PD), PD plus dementia of Alzheimer type (PDAT) or progressive supranuclear palsy (PSP), were studied with positron emission tomography (PET) using (18F)-2-fluoro-2-deoxy-D-glucose (FDG). In one patient with strictly unilateral PD side differences in striatal dopa uptake were studied with 6-(18F)fluoro-L-dopa (F-dopa). In patients with PD PET with FDG did not show any significant change in regional cerebral metabolic rates for glucose (rCMR(Glu)). In PDAT glucose metabolism was generally reduced, the most severe decrease was found in parietal cortex. The metabolic pattern was similar to that typically found in patients with Alzheimer's disease (AD). In the patient with strictly unilateral PD rCMR(Glu) was normal, F-dopa PET, however, revealed a distinct reduction of dopa uptake in the contralateral putamen. In PSP glucose metabolism was significantly decreased in subcortical regions (caudatum, putamen and brainstem) and in frontal cortex. Thus PET demonstrated a clear difference of metabolic pattern between PDAT and PSP. (authors)

  9. Recent innovations in the detection systems of Positron Emission Tomography

    International Nuclear Information System (INIS)

    Since the recognition of the clinical value of Positron Emission Tomography (PET) for the diagnosis and staging of several cancers, the PET systems have evolved to systems associating PET and Computed Tomography (CT). The main constraint for clinical imaging is to reduce the acquisition duration. As a consequence, PET detectors are faster and emit more light than the BGO crystal used previously. These detectors allow an improvement of the count rate performance of the PET systems, reducing the scattered and the random events while increasing the true events at high activity concentration. Among the new crystals, some allow measuring the time of flight of the annihilation photons. This measurement further improves the performance of the systems. The spatial resolution of clinical PET systems is still equal to 5 mm at best. High spatial resolution PET systems dedicated to small animal imaging have been developed. These systems use similar crystal materials as the clinical systems. However, in order to permit spatial resolution close to 1 mm, the crystal elements have much smaller transverse dimensions than that of clinical systems. The detectors are compact using position sensitive photomultipliers or photodiodes. In order to preserve the uniformity of the spatial resolution over the transverse field of view of the tomography, solutions allowing the measurement of the depth of interaction of the photons in the crystal have been designed. New compact detectors based on semi conductors are currently investigated. (author)

  10. 76 FR 47593 - Guidance for Small Business Entities on Current Good Manufacturing Practice for Positron Emission...

    Science.gov (United States)

    2011-08-05

    ... a guidance for small business entities entitled ``PET Drugs--Current Good Manufacturing Practice... entitled ``PET Drugs--Current Good Manufacturing Practice (CGMP); Small Entity Compliance Guide.'' This... Manufacturing Practice for Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug...

  11. Diagnostic value for extrahepatic metastases of hepatocellular carcinoma in positron emission tomography/computed tomography scan

    OpenAIRE

    2012-01-01

    AIM: To evaluated the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) scan in diagnosis of hepatocellular carcinoma (HCC) and extrahepatic metastases.

  12. Molecular pathology in vulnerable carotid plaques: correlation with [18]-fluorodeoxyglucose positron emission tomography (FDG-PET)

    DEFF Research Database (Denmark)

    Graebe, M; Pedersen, Sune Folke; Borgwardt, L;

    2008-01-01

    OBJECTIVES: Atherosclerosis is recognised as an inflammatory disease, and new diagnostic tools are warranted to evaluate plaque inflammatory activity and risk of cardiovascular events. We investigated [18]-fluorodeoxyglucose (FDG) uptake in vulnerable carotid plaques visualised by positron emission...

  13. Measurement of regional cerebral glucose utilization in man by positron emission tomography

    International Nuclear Information System (INIS)

    The various methods available for the study of regional cerebral glucose consumption in man by positron emission tomography are described and their applications, limitations and principal physiopathological results are presented

  14. Synthesis of the radiopharmaceuticals for positron emission tomography

    International Nuclear Information System (INIS)

    In this paper is shown a short overview of the biogenic positron radiopharmaceuticals production and a brief summary of some PET preparation synthesis. At the end the overview of some forward-looking positron radionuclides, which can be used for a preparation of the PET radiopharmaceuticals is said. A short review of diagnostic use of PET radiopharmaceuticals is presented (authors)

  15. Software development for modeling positrons emission tomograph scanners

    International Nuclear Information System (INIS)

    The Geant4 Application for Tomographic Emission (GATE) is an international platform recognized and used to develop Computational Model Exposure (CME) in the context of Nuclear Medicine, although currently there are dedicated modules for applications in Radiotherapy and Computed Tomography (CT). GATE uses Monte Carlo (MC) methods, and has a scripting language of its own. The writing of scripts for simulation of a PET scanner in GATE involves a number of interrelated steps, and the accuracy of the simulation is dependent on the correct setup of the geometries involved, since the physical processes depend on them, as well as the modeling of electronic detectors in module Digitizer, for example. The manual implementation of this setup can be a source of errors, especially for users without experience in the field of simulations or without any previous knowledge of a programming language, and also due to the the fact that the modeling process in GATE still remains bounded to LINUX / UNIX based systems, an environment only familiar to a few. This becomes an obstacle for beginners and prevents the use of GATE by a larger number of users interested in optimizing their experiments and/or clinical protocols through a more accessible, fast and friendly application. The objective of this work is therefore to develop a user-friendly software for the modeling of Positron Emission Tomography called GUIGATE (Graphical User Interface for GATE), with specific modules dedicated to quality control in PET scanners. The results exhibit the features available in this first version of GUIGATE, present in a set of windows that allow users to create their input files, perform and display in real time the model and analyze its output file in a single environment, allowing so intuitively access the entire architecture of the GATE simulation and to CERN's data analyzer, the ROOT. (author)

  16. A proposed method for the determination of cerebral regional intermediary glucose metabolism in humans in vivo using specifically labeled 11C-glucose and positron emission transverse tomography (PETT). I. An animal model with 14C-glucose and rat brain autoradiography

    International Nuclear Information System (INIS)

    Based upon data obtained with our arterio-venous technique for the determination of cerebral metabolism in humans in vivo we have proposed a method for the determination of cerebral regional intermediary glucose metabolism in humans in vivo using specifically labeled 11C-glucose and positron emission transverse tomography (PETT). In it we would give the subject successive intravenous injections of [3,4-11C] glucose, [2,5-11C] glucose and [1-11C] glucose. There would be a 30 min period of continuous PETT measurements following each injection and a 2 hr interval after the first and second injections. The data would be used with suitable equations and algorithms to estimate for each specific region of the subject's brain the dynamics of the Embden-Meyerhof-Parnas (EMP) and the tricarboxylic acid cycle (TCA) metabolic pathways and the incorporation of glucose carbons into lactate, and the extent of dilution of glucose carbons into lactate, and the extent of dilution of glucose carbons in traversing the TCA with their subsequent incorporation into other carbon pools of the brain (ie, glutamate, glutamine, GABA, alanine). Using 14C as a model for 11C and autoradiographs made with rat brain slices, we have produced an animal model to demonstrate the feasibility of our proposed method. The resulting autoradiographs have provided evidence of the validity of the predictions made from our arterio-venous data. The model was employed to show the selective reductions in the rates of incorporation of specific carbon atoms of glucose into regions of the rat brain and evidence of altered metabolic pathways following a single electroconvulsive shock (ECS) and after a series of nine ECS

  17. 18F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

    International Nuclear Information System (INIS)

    Uterine carcinosarcomas clinically confined to the uterus usually harbor occult metastases. We conducted a pilot study to evaluate the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in uterine carcinosarcoma. Patients with histologically confirmed uterine carcinosarcoma were enrolled. Abdominal and pelvic magnetic resonance imaging (MRI)/whole-body computed tomography (CT) scan, and whole-body 18F-FDG PET or PET/CT were undertaken for primary staging, evaluating response, and restaging/post-therapy surveillance. The clinical impact of 18F-FDG PET was determined on a scan basis. A total of 19 patients were recruited and 31 18F-FDG PET scans (including 8 scans performed on a PET/CT scanner) were performed. Positive impacts of scans were found in 36.8% (7/19) for primary staging, 66.7% (2/3) for monitoring response, and 11.1% (1/9) for restaging/post-therapy surveillance. PET excluded falsely inoperable disease defined by MRI in two patients. Aggressive treatment applying to three patients with PET-defined resectable stage IVB disease seemed futile. Two patients died of disease shortly after salvage therapy restaged by PET. With PET monitoring, one stage IVB patient treated by targeted therapy only was alive with good performance. Using PET did not lead to improvement of overall survival of this series compared with the historical control (n = 35) (P 0.779). The preliminary results suggest that 18F-FDG PET is beneficial in excluding falsely inoperable disease for curative therapy and in making a decision on palliation for better quality of life instead of aggressive treatment under the guidance of PET. PET seems to have limited value in post-therapy surveillance or restaging after failure. (orig.)

  18. Silicon as an unconventional detector in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a widely used technique in medical imaging and in studying small animal models of human disease. In the conventional approach, the 511 keV annihilation photons emitted from a patient or small animal are detected by a ring of scintillators such as LYSO read out by arrays of photodetectors. Although this has been successful in achieving ∼5mm FWHM spatial resolution in human studies and ∼1mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches including the potential for high intrinsic spatial resolution in 3D. To evaluate silicon in a variety of PET “magnifying glass” configurations, an instrument was constructed that consists of an outer partial-ring of PET scintillation detectors into which various arrangements of silicon detectors are inserted to emulate dual-ring or imaging probe geometries. Measurements using the test instrument demonstrated the capability of clearly resolving point sources of 22Na having a 1.5 mm center-to-center spacing as well as the 1.2 mm rods of a 18F-filled resolution phantom. Although many challenges remain, silicon has potential to become the PET detector of choice when spatial resolution is the primary consideration. -- Highlights: ► We examine the use of position-sensitive silicon detectors in magnifying PET geometries. ► A demonstrator using silicon detectors and BGO scintillation detectors was constructed. ► Both single-slice and volume PET configurations were tested. ► For a 4.5 cm field-of-view, resolutions <1mm were achievable. ► Resolution will improve further with higher resolution silicon detectors.

  19. Study of patients with spinocerebellar degeneration using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Susumu; Tanaka, Makoto; Sun, X.; Sakai, Yasujiro; Hirai, Shunsaku (Gunma Univ., Maebashi (Japan). School of Medicine)

    1993-10-01

    We studied cerebral blood flow, oxygen metabolism and their relation to clinical symptoms in 45 patients with spinocerebellar degeneration (SCD) and 12 normal control subjects using positron emission tomography (PET). Regions of interest were acquired for the cerebellar hemispheres, cerebellar vermis, brainstem, thalami, and cerebral cortices. PET studies revealed that regional cerebral blood flow (CBF), regional cerebral oxygen metabolic rate (CMRO[sub 2]), CBF/mean CBF of each cerebral cortex (CBF/mCBF) and CMRO[sub 2]/mean CMRO[sub 2] of each cerebral cortex (CMRO[sub 2]/mCMRO[sub 2]) in the cerebellar hemispheres, cerebellar vermis, and brainstem showed a significant decrease in comparison with the normal control subjects, while in the cerebral cortices and thalami, SCD patients showed normal values. CBF/mCBF and CMRO[sub 2]/mCMRO[sub 2] were significantly decreased in patients with olivo-pontocerebellar atrophy (OPCA) and Menzel type of hereditary ataxia (Menzel type) in the cerebellar hemispheres, cerebellar vermis, and brainstem, whereas patients with late cortical cerebellar atrophy (LCCA) and Holmes type of hereditary ataxia (Holmes type) revealed a significant decrease of CBF/mCBF and CMRO[sub 2]/mCMRO[sub 2] in the cerebellar hemispheres and cerebellar vermis, but not in the brainstem. Patients with OPCA showed a significant decrease of CBF in the cerebellar hemispheres, cerebellar vermis, brainstem and that of CMRO[sub 2] in the cerebellar hemispheres and cerebellar vermis. Patients with LCCA showed a significant decrease of CBF in the right cerebellar hemisphere and cerebellar vermis. In patients with LCCA and Holmes type, the severity of upper limb ataxia and dysdiadochocinesis were significantly correlated with CBF/mCBF and CMRO[sub 2]/mCMRO[sub 2] in the cerebellar hemispheres and brainstem. PET may be useful for diagnosing SCD and understanding its pathogenesis. (author).

  20. Positron emission tomography in patients with drug-resistant epilepsy

    International Nuclear Information System (INIS)

    Positron emission tomography with 18Fluor-deoxyglucose (18FDG PET) was introduced as method of evaluation of the cerebral metabolism in the early 80s. 18FDG PET/computed tomography (PET/CT) has rapidly become a method of epileptogenic zone localization because of the hypometaboilsm of this zone during the interictal period. This paper represents the first Bulgarian series of patients with drug- resistant epilepsy who were evaluated with 18FDG PET as part of the presurgical work-up. Our study has included 21 patients with drug-resistant epilepsy who were evaluated with 18FDG PET/CT from January 2010 to May 2013. All patients were evaluated with dedicated MRI epilepsy protocol. PET/CT study was fused with 3D MRI study using FSL or GE software. Video EEG monitoring was performed in all 21 patients and seizures were recorded in 18 patients. Hypometabolic zones were found in 15 patients. The hypometabolism was focal in 5 patients, multilobar in 9 patients and hemispheric in 1 patient. The MRI was normal in 8 patients. Hypometabolic zones were found in 3 of these 8 patients with cryptogenic epilepsy. Epilepsy surgery was performed in 6 cases. All operated patients were with hypometabolic zones. Significant seizure reduction after surgery was observed in 5 of 6 operated patients. 18FDG PET/CT is a valuable method for epileptogenic zone localization in patients with drug-resistant epilepsy. The introduction of this method in the bulgarian epilepsy surgery program increases the chances for successful resective surgery. (authors)

  1. Positron Emission Tomography in the Management of Lung Cancer (NSCLC)

    International Nuclear Information System (INIS)

    Lung cancer is the leading cause of cancer deaths in men and the second most common cancer in women. Globally it remains the most commonly diagnosed cancer at 1.35 million, representing 12.4% of all new cancers. Almost half (49.9%) of the lung cancer cases occur in the developing countries of the world, which is a big change since 1980, when it was estimated that 69% were in developed countries. Although lung cancer is the most deadly of all the cancers, it is the only major cancer that does not have a widely accepted screening test. Lung cancer often presents as a solitary pulmonary nodule on chest radiographs, which are usually performed on patients as a preoperative screening test, or as a part of routine health screening, often in the absence of symptoms. Incidental detection can occur in up to 12% of cases in asymptomatic cases. It is clear that there is a need for the accurate diagnosis of these lesions. In recent years Positron early and Emission Tomography (PET) holds early and promise as a noninvasive investigative tool for the evaluation of lung cancer. 18F-FDG PET is currently indicated for the characterization of lung lesions, staging of non-small cell lung carcinoma (NSCLC), detection of distant metastases, and diagnosis of recurrent disease. PET/CT studies are also being increasingly employed in radiotherapy treatment also planning. Furthermore PET also plays an important role in monitoring of treatment response. On the face of it a PET-CT study may appear expensive. But in the overall context, PET/CT is cost-effective in the treatment of Lung cancer. The modality is the best discriminator of disease load if used in the correct clinical setting. It can do away with the need for multiple, many times needless investigations. It can reduce the number of futile operations, unwarranted interventions, as well as over and under treatments of lung cancer. (author)

  2. Positron emission tomography in urological cancer; Positronenemissionstomographie bei urologischen Tumoren

    Energy Technology Data Exchange (ETDEWEB)

    Wit, M. de [Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Abt. Onkologie/Haematologie, Medizinische Klinik; Kotzerke, J. [Universitaetsklinikum Ulm (DE). Radiologie III (Nuklearmedizin)

    2000-09-01

    In staging cancer of the urinary bladder, the kidneys and the prostate and of testicular cancer there is a need for detecting tumor involvement of the lymph nodes to avoid surgical exploration. Positron emission tomography (PET) using fluorodeoxyglucose (FDG) can detect tumorous lymph nodes (sensitivity: 70%, specificity: 85%) which is helpful for several patients. In carcinoma of the prostate, other radiotracers than FDG (e.g. C-11-choline) might be more sensitive to detect tumorous lymph nodes. Up to now no diagnostical benefit of PET in germ cell tumors could be demonstrated in the published small series. In principle FDG-PET is useful in diagnosis of recurrence. In germ cell cancer FDG-PET seems to identify effectively persistent vital tumor tissue after chemotherapy. A multicenter study was initiated to demonstrate the potential of FDG-PET in a sufficient number of patients with germ cell tumor. (orig.) [German] Bei Harnblasen-, Nieren-, Prostata- und Hodenkarzinomen besteht aus klinischer Sicht ein Bedarf an verbessertem Lymphknoten-Staging, um die operative Evaluation zu vermeiden. Die Positronenemissionstomographie (PET) mit Fluordeoxyglukose (FDG) kann daher im Einzelfall bei Harnblasen- und Nierenkarzinomen hilfreich sein (bei Sensitivitaet um 70% und Spezifitaet um 85%). Beim Prostatakarzinom koennten sich andere Radiotracer (z.B. C-11-Cholin) bei der Detektion von tumoroesen Lymphknoten ueberlegen erweisen. Bei Keimzelltumoren konnte ein Nutzen der PET im primaeren Staging bei den bisher publizierten kleinen Studien nicht nachgewiesen werden. Fuer die Rezidivdiagnostik ist bei den genannten Tumoren aus grundsaetzlicher Ueberlegung der Einsatz von DFG-PET sinnvoll. Die Erkennung von vitalem malignen Tumorgewebe nach Chemotherapie erscheint bei Keimzelltumoren mit FDG-PET weitgehend sicher zu gelingen. Eine multizentrische Studie wurde begonnen, die hierueber Aufschluss geben wird. (orig.)

  3. Noninvasive alternatives to arterial blood sampling in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography is commonly employed for the quantitative assessment of regional biochemistry. The determination of glucose and oxygen utilization rates using [F-18] 2FDG and [0-15] 0/sub 2/ demand accurate measurement of the driving function producing the observed tissue response. Conventional techniques consist of an arterial or venous puncture with either discrete or continuous sampling of blood label concentrations. A time-of-flight (TOF) probe and expired gas detector have been developed as alternatives to these invasive techniques. The acquisition of serial spectra with the TOF pair (4 x 4cm BaF/sub 2/;XP2020Q;380 psec FWHM), sampling a line through the cardiac chambers, reveals the spatial distribution of activity in the heart and surrounding tissue as a function of time. Region-of-interest analysis of the temporally resolved spectra produce the activity time courses required for analysis of tissue response data. Multigated TOF acquisition using a pulsewatch (LED-phototransistor pair which detects finger-tip blood volume changes) as the gating mechanism promises to provide an easy and accurate method for positioning the TOF probe. Dynamic techniques for the measurement of oxygen utilization rates require both the arterial [0-15] 0/sub 2/ and [0-15] H/sub 2/O concentrations. A heated flow-through plastic (NE 102) beta detector was developed to measure the concentration of label in the alveolar gas which was equilibrated with the blood in the pulmonary capillaries. Combining the TOF probe and expired gas data allows the separation of the oxygen and water components of the input function

  4. Analysis of Factors Affecting Positron Emission Mammography (PEM) Image Formation

    International Nuclear Information System (INIS)

    Image reconstruction for positron emission mammography (PEM) with the breast positioned between two parallel, planar detectors is usually performed by backprojection to image planes. Three important factors affecting PEM image reconstruction by backprojection are investigated: (1) image uniformity (flood) corrections, (2) image sampling (pixel size) and (3) count allocation methods. An analytic expression for uniformity correction is developed that incorporates factors for spatial-dependent detector sensitivity and geometric effects from acceptance angle limits on coincidence events. There is good agreement between experimental floods from a PEM system with a pixellated detector and numerical simulations. The analytic uniformity corrections are successfully applied to image reconstruction of compressed breast phantoms and reduce the necessity for flood scans at different image planes. Experimental and simulated compressed breast phantom studies show that lesion contrast is improved when the image pixel size is half of, rather than equal to, the detector pixel size, though this occurs at the expense of some additional image noise. In PEM reconstruction counts usually are allocated to the pixel in the image plane intersected by the line of response (LOR) between the centers of the detection pixels. An alternate count allocation method is investigated that distributes counts to image pixels in proportion to the area of the tube of response (TOR) connecting the detection pixels that they overlay in the image plane. This TOR method eliminates some image artifacts that occur with the LOR method and increases tumor signal-to-noise ratios at the expense of a slight decrease in tumor contrast. Analysis of image uniformity, image sampling and count allocation methods in PEM image reconstruction points to ways of improving image formation. Further work is required to optimize image reconstruction parameters for particular detection or quantitation tasks

  5. Effect of tissue heterogeneity on quantification in positron emission tomography

    International Nuclear Information System (INIS)

    As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMRglc in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constans such as k2 and k3 for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameter kon.Bmax could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity, Bmax was found to be insensitive while Kd was very sensitive to tissue heterogeneity. (orig.)

  6. Effect of tissue heterogeneity on quantification in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blomqvist, G. [Dept. of Clinical Neuroscience, Experimental Alcohol and Drug Addiction Research Section, Karolinska Hospital, Stockholm (Sweden); Lammertsma, A.A. [PET Methodology Group, Cyclotron Unit, MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, London (United Kingdom); Mazoyer, B. [Service Hospitalier Frederic Joliot CEA/Dept. de Biologie, Hopital d`Orsay and Antenne d`Informatique Medicale, Hopital Robert Debre, Paris (France); Wienhard, K. [Max-Planck-Inst. fuer Neurologische Forschung, Koeln (Germany)

    1995-07-01

    As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMR{sub glc} in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constans such as k{sub 2} and k{sub 3} for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameter k{sub on}.B{sub max} could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity, B{sub max} was found to be insensitive while K{sub d} was very sensitive to tissue heterogeneity. (orig.)

  7. [Capabilities of positron emission tomography to study mecha-nisms of multiple sclerosis: own data and literature].

    Science.gov (United States)

    Stolyarov, I D; Petrov, A M; Shkil'nyuk, G G; Kataeva, G V; Prakhova, L N

    2016-01-01

    The article presents the literature data and results of our own researchon the use of positron emission tomography (PET) with different radiotracersin multiple sclerosis (MS). Informationon the operating principles of PET and PET studies with different radiotracers are considered. The results of PET studiesin different typesof MS, including determinationof the localization of neuronal damagein the corticalgray matter, assessmentof microglial activation, study of the relationship between glucose metabolismin the brain and the severity of cognitive impairmentin MS, can providenew information about the pathogenesis ofMS. PMID:27070358

  8. Positron emission tomography assessment of effects of benzodiazepines on regional glucose metabolic rate in patients with anxiety disorder

    International Nuclear Information System (INIS)

    Patients with generalized anxiety disorder (n = 18) entered a 21-day, double-blind, placebo-controlled random assignment trial of clorazepate. Positron emission tomography with 18F-deoxyglucose was carried out before and after treatment. Decreases in glucose metabolic rate in visual cortex and relative increases in the basal ganglia and thalamus were found. A correlation between regional changes in metabolic rate and regional benzodiazepine receptor binding density from other human autopsy studies was observed; brain regions highest in receptor density showed the greatest decrease in rate

  9. Positron emission tomography assessment of effects of benzodiazepines on regional glucose metabolic rate in patients with anxiety disorder

    Energy Technology Data Exchange (ETDEWEB)

    Buchsbaum, M.S.; Wu, J.; Haier, R.; Hazlett, E.; Ball, R.; Katz, M.; Sokolski, K.; Lagunas-Solar, M.; Langer, D.

    1987-06-22

    Patients with generalized anxiety disorder (n = 18) entered a 21-day, double-blind, placebo-controlled random assignment trial of clorazepate. Positron emission tomography with YF-deoxyglucose was carried out before and after treatment. Decreases in glucose metabolic rate in visual cortex and relative increases in the basal ganglia and thalamus were found. A correlation between regional changes in metabolic rate and regional benzodiazepine receptor binding density from other human autopsy studies was observed; brain regions highest in receptor density showed the greatest decrease in rate.

  10. Neuroleptic binding sites: specific labeling in mice with [18F]haloperidol, a potential tracer for positron emission tomography

    International Nuclear Information System (INIS)

    Haloperidol labeled with fluorine-18 (T 1/2 . 110 min, positron emission 97%), prepared yielding .04 Ci/millimole by the Balz-Schiemann reaction, was evaluated in a murine model as a potential radiotracer for noninvasive determination, by positron-emission tomography, of regional concentrations of brain dopamine receptors in patients. As the haloperidol dose in mice was increased from 0.01 to 1000 micrograms/kg, the relative concentration of [18F]haloperidol (microCi per g specimen/microCi per g of body mass), at one hour after injection decreased from 30 to 1.0 in the striatum and from 8.0 to 1.0 in the cerebellum. The striatal radioactivity, plotted as relative concentration against log of dose, decreased sigmoidally, presumably reflecting competition between labeled and unlabeled haloperidol for a single class of accessible binding sites. Because the cerebellum is relatively deficient in dopamine receptors, the observed decrease in cerebellar radioactivity may reflect a saturable component of haloperidol transport into brain. The high brain concentrations and the unexpectedly high striatum-to-cerebellum concentration ratios (greater than 4 at haloperidol doses less than or equal to 1 microgram/kg) suggest that [18F]haloperidol warrants further investigation as a potential radiotracer for dopamine receptors

  11. 18F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging findings of primary intracranial histiocytic sarcoma in a dog

    International Nuclear Information System (INIS)

    A 10-year-old, neutered male, Maltese dog presented with a three week history of intention tremor, right hind limb rigidity, poor coordination, and occasional circling to the left. On magnetic resonance imaging (MRI) of the brain, a mass was identified in the right occipital lobe and cerebellum. Three weeks after the initial MRI scan, we performed an sup(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) of the brain. The FDG-PET demonstrated areas of hypermetabolism in the right occipital lobe, cerebellum, pons, and medulla oblongata. When the standardized uptake value was calculated, the hypermetabolic lesion was higher than the gray matter values. The anatomical location of the hypermetabolic lesion was more precisely identified by the PET-MRI fusion images. The dog was definitively diagnosed as a primary histiocytic sarcoma of the brain. This is the first report of PET findings of an intracranial histiocytic sarcoma in a dog

  12. Preclinical studies on [{sup 11}C]MPDX for mapping adenosine A{sub 1} receptors by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ishiwata, Kiichi; Kimura, Yuichi; Oda, Keiichi; Kawamura, Kazunori; Ishii, Kenji; Senda, Michio [Tokyo Metropolitan Inst. of Gerontology (Japan). Positron Medical Center; Nariai, Tadashi; Wakabayashi, Shinichi [Tokyo Medical and Dental Univ. (Japan). School of Medicine; Shimada, Junichi [Kyowa Hakko Kogyo Co. Ltd., Tokyo (Japan). Pharmaceutical Research Inst.

    2002-09-01

    In previous in vivo studies with mice, rats and cats, we have demonstrated that [{sup 11}C]MPDX ([1-methyl-{sup 11}C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine) is a potential radioligand for mapping adenosine A{sub 1} receptors of the brain by positron emission tomography (PET). In the present study, we performed a preclinical study. The radiation absorbed-dose by [{sup 11}C]MPDX in humans estimated from the tissue distribution in mice was low enough for clinical use, and the acute toxicity and mutagenicity of MPDX were not found. The monkey brain was clearly visualized by PET with [{sup 11}C]MPDX. We have concluded that [{sup 11}C]MPDX is suitable for mapping adenosine A{sub 1} receptors in the human brain by PET. (author)

  13. Positron emission tomography displacement sensitivity: predicting binding potential change for positron emission tomography tracers based on their kinetic characteristics.

    Science.gov (United States)

    Morris, Evan D; Yoder, Karmen K

    2007-03-01

    There is great interest in positron emission tomography (PET) as a noninvasive assay of fluctuations in synaptic neurotransmitter levels, but questions remain regarding the optimal choice of tracer for such a task. A mathematical method is proposed for predicting the utility of any PET tracer as a detector of changes in the concentration of an endogenous competitor via displacement of the tracer (a.k.a., its 'vulnerability' to competition). The method is based on earlier theoretical work by Endres and Carson and by the authors. A tracer-specific predictor, the PET Displacement Sensitivity (PDS), is calculated from compartmental model simulations of the uptake and retention of dopaminergic radiotracers in the presence of transient elevations of dopamine (DA). The PDS predicts the change in binding potential (DeltaBP) for a given change in receptor occupancy because of binding by the endogenous competitor. Simulations were performed using estimates of tracer kinetic parameters derived from the literature. For D(2)/D(3) tracers, the calculated PDS indices suggest a rank order for sensitivity to displacement by DA as follows: raclopride (highest sensitivity), followed by fallypride, FESP, FLB, NMSP, and epidepride (lowest). Although the PDS takes into account the affinity constant for the tracer at the binding site, its predictive value cannot be matched by either a single equilibrium constant, or by any one rate constant of the model. Values for DeltaBP have been derived from published studies that employed comparable displacement paradigms with amphetamine and a D(2)/D(3) tracer. The values are in good agreement with the PDS-predicted rank order of sensitivity to displacement. PMID:16788713

  14. New techniques for positron emission tomography in the study of human neurological disorders

    International Nuclear Information System (INIS)

    This progress report represents a summary of our performance during the two year period following initial start-up of these research activities at Michigan. Productivity has been excellent; already over 47 papers and abstracts have been published or accepted for publication from this still young program. They represent significant contributions to extending the technology of positron emission tomography in the study of human neurological disorders. Our focus is to develop more cost effective and efficient means for producing new functionally specific tracers and simpler, less expensive, means for acquiring and interpreting quantitative data. These improved processes are required for the future growth of PET as a sophisticated research tool and for the transfer of this technology to clinical use. Our approach concentrates on two separate yet related areas, radiosynthesis and data analysis. In subproject 1, Drs. Jewett and Mulholland have introduced innovative methods for improving 11C and 18F synthetic processes. In Subproject 2, Dr. Hutchins has laid the foundations for an objective analysis of the limitations and opportunities for quantifying regional PET data. In Subproject 3, Dr. Koeppe has extended rapid techniques for parameter estimation in kinetic modeling of new ligands. Finally, in Subproject 4, Dr. Frey has applied kinetic analysis to ligand tracing of the cholinergic neurotransmitter system in animal and human brain. These DOE supported studies have direct impact on clinical research here and elsewhere which is expected to improve diagnosis and treatment of degenerative neurological diseases, mental illness and brain tumors. 47 refs., 7 figs., 4 tabs

  15. Positron emission tomographic scan investigations of Huntington's disease: cerebral metabolic correlates of cognitive function

    International Nuclear Information System (INIS)

    Fifteen drug-free patients with early to mid-stage Huntington's disease (HD) were evaluated with positron emission tomographic (PET) scans of 18F-2-fluoro-2-deoxy-D-glucose uptake and quantitative measures of neurological function, learning, memory, and general intelligence. In comparison with a group of normal volunteers, the HD patients showed lower metabolism in both caudate (p less than 0.001) and putamen (p less than 0.001) on PET scans. A significant and positive relationship was found between neuropsychological measures of verbal learning and memory and caudate metabolism in the patient group but not in the normal group. Visual-spatial learning did not reflect a similar pattern, but performance intelligence quotient was positively related to both caudate and putamen metabolism in the HD group. Vocabulary level was unrelated to either brain structure. Discussion focuses on these and other observed brain-behavior relationships and on the implications of these findings for general behaviors such as those involved in coping and adaptation

  16. Positron emission tomography-computed tomography in the management of lung cancer: An update

    Directory of Open Access Journals (Sweden)

    Punit Sharma

    2013-01-01

    Full Text Available This communication presents an update on the current role of positron emission tomography-computed tomography (PET-CT in the various clinical decision-making steps in lung carcinoma. The modality has been reported to be useful in characterizing solitary pulmonary nodules, improving lung cancer staging, especially for the detection of nodal and metastatic site involvement, guiding therapy, monitoring treatment response, and predicting outcome in non-small cell lung carcinoma (NSCLC. Its role has been more extensively evaluated in NSCLC than small cell lung carcinoma (SCLC. Limitations in FDG PET-CT are encountered in cases of tumor histotypes characterized by low glucose uptake (mucinous forms, bronchioalveolar carcinoma, neuroendocrine tumors, in the assessment of brain metastases (high physiologic 18F-FDG uptake in the brain and in cases presenting with associated inflammation. The future potentials of newer PET tracers beyond FDG are enumerated. An evolving area is PET-guided assessment of targeted therapy (e.g., EGFR and EGFR tyrosine kinase overexpression in tumors which have significant potential for drug development.

  17. Metabolic and circulatory evaluation of acute cerebral ischaemic accidents in man by positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography and oxygen-15 were used to evaluate the effects of an almitrine-raubasine combination on cerebral blood flow and oxydative metabolism in patients with acute cerebral ischaemia. In 5 patients, aged between 58 and 74 years, with cerebral ischaemic accident in the territory of the middle cerebral artery, blood flow rate, oxygen consumption and brain oxygen extraction were measured before and after a 90-min intravenous infusion of almitrine bismesilate 15 mg and raubasine 5 mg. Only one patient presented with initial relative luxury perfusion, the intensity of which was reduced by the combined treatment. The other 4 patients had focal reduction of cerebral blood flow and oxygen consumption prior to treatment. Satistical analysis conducted on three cerebral areas (epicentre of the lesion, anterior and posterior juxtalesional areas and homologous heterolateral areas) showed a significant 3.6% increase of oxygen consumption in the epicentre, both hemispheres included, and a significant increase of cerebral blood flow in all three areas (3% on the healthy side, 13% on the diseased side). No significant change in oxygen extraction was demonstrated. The authors conclude that acute almitrine-raubasine treatment has beneficial effects on the brain immediately after a cerebral vascular accident, reflecting respect of the circulation-metabolism couple

  18. Preparation of a potential positron emission tomographic radioligand for the dopamine transporter

    International Nuclear Information System (INIS)

    NNC 12-0722 (1-[2-(bis(4-fluorophenyl)-methoxy)ethyl]-4-methyl piperazine) is a new selective inhibitor of the dopamine transporter. [11C]NNC 12-0722 was prepared by N-methylation of the desmethyl compound with [11C]methyl iodide. The total radiochemical yield of [11C]NNC 12-0722 was 40%-50% with an overall synthesis time of 30-35 min. The radiochemical purity was higher than 99% and the specific radioactivity about 1500 Ci/mmol (55 GBq/μmol). Autoradiographic examination of [11C]NNC 12-0722 binding on whole hemisphere cryosections from human brain post mortem demonstrated specific binding in the caudate nucleus and putamen. In a positron emission tomographic examination of [11C]NNC 12-0722 in a cynomolgus monkey there was a rapid uptake of radioactivity in the brain. In the striatum, a region with a high density of dopamine transporters, the radioactivity was two times higher than in the cerebellum. These results indicate that [11C]NNC 12-0722 may be a useful radioligand for labelling of the dopamine transporter in man. (orig.)

  19. Regional Cerebral Glucose Metabolism in Novelty Seeking and Antisocial Personality: A Positron Emission Tomography Study

    Science.gov (United States)

    Park, So Hyeon; Park, Hyun Soo

    2016-01-01

    Novelty seeking (NS) and antisocial personality (ASP) are commonly exhibited by those who suffer from addictions, such as substance abuse. NS has been suggested to be a fundamental aspect of ASP. To investigate the neurobiological substrate of NS and ASP, we tested the relationship between regional cerebral glucose metabolism and the level of NS, determining the differences between individuals with and without ASP. Seventy-two healthy adults (43 males, mean age±SD=38.8±16.6 years, range=20~70 years; 29 females, 44.2±20.1 years, range=19~72 years) underwent resting-state brain positron emission tomography (PET) 40 minutes after 18F-fluorodeoxyglucose (FDG) injection. Within 10 days of the FDG PET study, participants completed Cloninger's 240-item Temperament and Character Inventory (TCI) to determine NS scores. Participants with and without ASP were grouped according to their TCI profiles. Statistical parametric mapping analysis was performed using the FDG PET and TCI profile data. NS scores positively correlated with metabolism in the left anterior cingulate gyrus and the insula on both sides of the brain and negatively correlated with metabolism in the right pallidum and putamen. Participants with ASP showed differences in cerebral glucose metabolism across various cortical and subcortical regions, mainly in the frontal and prefrontal areas. These data demonstrate altered regional cerebral glucose metabolism in individuals with NS and ASP and inform our understanding of the neurobiological substrates of problematic behaviors and personality disorders. PMID:27574485

  20. Determination of cerebral metabolic patterns in dementia using positron emission tomography

    International Nuclear Information System (INIS)

    With the introduction of the Kety-Schmidt method whole brain measurements of blood flow and metabolism were first applied to normal aged and demented patients. Chronically demented patients were consistently found to have marked reductions in cerebral blood flow, oxygen utilization, and glucose utilization when dementia was severe, and lesser reductions when it was mild. Others found that cerebral blood flow, oxygen utilization, and glucose utilization were decreased in parallel in late stages of Alzheimer's disease (AD) and multiple infarct dementia (MID). The intraarterial /sup 133/Xe method has been used to determine abnormalities in regional cerebral blood flow that correlate with cognitive deficits in patients with organic dementia, mostly Alzheimer's cases. Positron emission tomography (PET) and the /sup 18/F fluorodeoxyglycose (FDG) method have been applied to small numbers of demented patients with advanced AD. In general, decreases were found in global cerebral glucose utilization, but especially in temporal and parietal cortex. Others, using PET and the /sup 15/O/sub 2/ steady-state method, found a coupled decline in global cerebral blood flow and oxygen utilization that was correlated with increasing severity of dementia in both AD and MID, but there was no increase in oxygen extraction ratio, and therefore no evidence to support the existence of a chronic ischemic brain process. In this chapter, the author reviews some of the recent findings at UCLA using PET and the method in the study of normal aging and dementing disorders

  1. Positron emission tomography in patients with head and neck carcinoma

    International Nuclear Information System (INIS)

    PURPOSE: To examine the role of positron emission tomography (PET) with labeled fluorodeoxyglucose (FDG) in patients with primary neoplasms of the head and neck. MATERIALS and METHODS: Between (9(92)) and (9(94)), forty-four FDG PET scans were performed on 27 patients with head and neck neoplasms. FDG uptake at the tumor sites was quantified with standardized uptake values (SUV). There were seven women and 20 men. Median age was 70 (37 - 85). All patients had squamous cell carcinoma except two with esthesioneuroblastoma. In six patients the primary site was occult and treatment consisted of surgery followed by radiation. In the other patients, primary sites included nasopharynx (2), base of tongue (6), tonsil (4), larynx (2), piriform sinus (3) paranasal sinuses (3) and multiple (1). Three were Stage II, four were Stage III, 11 were Stage IV and three had recurrent disease. Gross disease was treated by radiation (2), twice daily radiation (8) or concurrent chemotherapy and radiation (11). The median follow-up of survivors is 12 months (6 - 30). RESULTS: All patients had baseline scans prior to radiation therapy. In the six patients with occult primaries, no primary lesions were discovered by PET scans. In the other 21 patients, all known primary sites, regional node metastases and distant metastases demonstrated increased uptake on PET imaging. In one patient distant metastases were suggested on PET (but without corroborating clinical or radiographic evidence) and in two patients additional regional node metastases were discovered. Eleven patients had PET scans at the conclusion of radiation therapy. Five patients had complete responses by PET, two had major responses and four had partial responses. However, all these patients had good clinical responses and none have failed locally. Five patients had six scans during follow-up (at 3 to 12 months) to differentiate radiation changes from persistent disease. In four patients the PET scans were negative and they are

  2. Fabrication of polycrystalline scintillators for the positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Transparent ceramics are becoming more and more important for two new types of applications. On the one hand in cases where high mechanical and thermal demands in combination with optical properties are required, on the other hand where the optical properties of transparent materials like glass are not sufficient e.g. in positron-emission-tomography (PET) diagnostics. Most state of the art PET-scanners are using high-priced single crystals as scintillator material. The technological challenge is to replace single crystal by cost-efficient transparent ceramics. Producing transparent ceramics is ordered in synthesis of the powders and in manufacturing of these into transparent ceramics. The aim of this work was to synthesize single phase yttrium-alumina-and Luthetiumalumina-garnet (YAG, LuAG) powders partially doped with neodymium or praseodymium by four different synthesis routes (Pechini-synthesis, sol-gel-route, coprecipitation and solid state reactions). Additionally industrial LuAG and LuPO4 powders were characterized and manufactured. The powders were processed as submicron- and nanopowders. The compaction of nanopowder greenbodies sintered at high temperatures leads to a ''cross-over'' between both manufacturing route. Newly produced single-phase powders were homogenized with additions of sintering additives like tetraethyl orthosilicate (TEOS) and binders like polyvinyl alcohol (PVA). Moulding the powders were carried out by uniaxial pressing, cold isostatic pressing and in individual cases also by slip casting. The achieved green densities were in a range of 25-42 %. Examination of calcination behaviour leads to a calcination temperature of 1000 C with 2 hours dwell time in air atmosphere. Only solid state reactions resulted into transparent YAG, YAG:Pr, LuAG, LuAG:Pr ceramics. Solid state reactions of nanopowders resulted in heterogeneously transparent samples. Ceramics made by powders of other synthetic routes gave nontransparent ceramics due to porosity

  3. Hyperventilation-induced reduction in cerebral blood flow: Assessment by positron emission tomography

    International Nuclear Information System (INIS)

    The use of positron emission tomography (PET) has been well documented as a relatively noninvasive method of measuring cerebral blood flow (CBF), both globally and regionally. The utility of readily detecting alterations in CBF is apparent, particularly when applied to the evaluation of therapeutic interventions thought to influence CBF. We report the effects of hypocapnia, an experimental condition of known cerebral vasoconstriction, in ten normal volunteers. Subjects had brain blood flow evaluated utilizing H215O as the positron emitter before and after approximately five minutes of hyperventilation. Baseline CBF was measured as a mean +/- SD of 61.2 +/- 16.3 mL/min/100 g of tissue. Mean baseline arterial blood gas values were PaO2 107.4 +/- 14 mm Hg, PaCO2 37.7 +/- 0.89 mm Hg, and pH 7.39 (calculated from mean [H+]). Post hyperventilation, global CBF was measured as 31.1 +/- 10.8 mL/min/100 g. Mean arterial blood gas values were PaO2 141.7 +/- 21 mm Hg, PaCO2 19.7 +/- 5 mm Hg, and pH 7.63 (calculated from mean [H+]). CBF decreased by a mean of 49.5 +/- 11 percent. Data analysis using the Student's t-test showed a significant change over baseline in PaCO2 (p less than 0.001) and CBF (p less than 0.001), in the hyperventilated state. Correlations were noted between the decrease in CBF and change in PaCO2 (r = 0.81) as well as between hyperventilation PaCO2 and the change in CBF (r = 0.97). We conclude that, as measured by PET, CBF decreases significantly during a state of artificial hyperventilation to a degree consistent with results seen using other methods. PET appears to be a valuable tool in the assessment of interventions that could influence CBF

  4. Laparoscopic Scar: a mimicker of Sister Mary Joseph's nodule on positron emission tomography/CT

    International Nuclear Information System (INIS)

    Positron emission tomography/CT is an established imaging method in the diagnosis and staging of cancers. 18F-fluoro-2-deoxy-D-glucose (FDG) is the most commonly used radiotracer in positron emission tomography/CT. It is a tumour viability agent and usually its uptake within a lesion reflects the presence of a viable tumour tissue. However, false-positive FDG uptake is known to occur in benign processes of either inflammatory or infectious aetiology. We describe FDG uptake at the site of laparoscopic scar that mimicked Sister Mary Joseph's nodule in a patient with gastric adenocarcinoma. Here, the knowledge of the patient's history and subtle imaging findings helped in accurate staging of the patient. In this case report, we emphasize the value of the knowledge of the patient history and awareness of different pitfalls of FDG to achieve a correct diagnosis on positron emission tomography/CT

  5. A new iterative reconstruction technique for attenuation correction in high-resolution positron emission tomography

    International Nuclear Information System (INIS)

    A new interative reconstruction technique (NIRT) for positron emission computed tomography (PET), which uses transmission data for nonuniform attenuation correction, is described. Utilizing the general inverse problem theory, a cost functional which includes a noise term was derived. The cost functional was minimized using a weighted-least-square maximum a posteriori conjugate gradient (CG) method. The procedure involves a change in the Hessian of the cost function by adding an additional term. Two phantoms were used in a real data acquisition. The first was a cylinder phantom filled with uniformly distributed activity of 74 MBq of fluorine-18. Two different inserts were placed in the phantom. The second was a Hoffman brain phantom filled with uniformly distributed activity of 7.4 MBq of 18F. Resulting reconstructed images were used to test and compare a new interative reconstruction technique with a standard filtered backprojection (FBP) method. The results confirmed that NIRT, based on the conjugate gradient method, converges rapidly and provides good reconstructed images. In comaprison with standard results obtained by the FBP method, the images reconstructed by NIRT showed better noise properties. The noise was measured as rms% noise and was less, by a factor of 1.75, in images reconstructed by NIRT than in the same images reconstructed by FBP. The distance between the Hoffman brain slice created from the MRI image was 0.526, while the same distance for the Hoffman brain slice reconstructed by NIRT was 0.328. The NIRT method suppressed the propagation of the noise without visible loss of resolution in the reconstructed PET images. (orig.)

  6. Pioneering and fundamental achievements on the development of positron emission tomography (PET) in oncology

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG), a glucose analog, is widely used throughout the world as an indispensable imaging modality for the management of cancer treatment. This article reviews the pioneering achievements of PET in oncology with a focus on the development of PET that occurred from 1980 through the early-1990s. 18F-FDG was first applied for imaging of animal tumors in 1980 and for brain tumor imaging clinically in 1982. 18F-FDG enabled to visualize liver metastasis as clear positive image that could not be obtained by conventional nuclear imaging. Subsequently, 18F-FDG was used for imaging various cancers, such as lung, pancreas, colorectal and hepatoma. 11C-L-methionine (11C-MET) that reflects amino acid transport of cancers has an advantage that its uptake is lower in the brain and inflammatory tissue compared to 18F-FDG, and was first applied for imaging lung cancer and brain tumor. 18F-FDG and 11C-MET were proved to be sensitive tracers that can be used to objectively evaluate the effectiveness of cancer treatment. The diagnostic accuracy of PET, which is critical in clinical practice, was evaluated for the differential diagnosis of malignant and benign lung nodules using 18F-FDG or 11C-MET. In addition to 18F-FDG and 11C-MET, many radiopharmaceuticals were developed, such as 18F-labled thymidine analogs for evaluating proliferative activity, 18F-fluoromisonidazole for imaging of hypoxia, and 18F-fluorodeoxygalactose for evaluating liver-specific galactose metabolism and for imaging of hepatoma that retains galactose metabolic activity. These early efforts and achievements have greatly contributed to the development and clinical application of 18F-FDG PET in oncology. (author) 113 refs.

  7. The 511 keV emission from positron annihilation in the Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Prantzos, N.; Boehm, C.; Bykov, A. M.; Diehl, R.; Ferriere, K.; Guessoum, N.; Jean, P.; Knoedlseder, J.; Marcowith, A.; Moskalenko, I. V.; Strong, A.; Weidenspointner, G. [CNRS, UMR7095, UMPC and Institut d' Astrophysique de Paris, F-75014, Paris (France) and LAPP, 9 Chemin de Bellevue, BP 110 F-74941 Annecy-le-Vieux (France); A. F. Ioffe Institute of Physics and Technology, Russian Academy of Sciences, 194021, St. Petersburg (Russian Federation); Max Planck Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany); Laboratoire d' Astrophysique de Toulouse-Tarbes, Universite de Toulouse, CNRS, 14 avenue Edouard Belin, F-31400 Toulouse (France); American University of Sharjah, College of Arts and Sciences/Physics Department, P.O. Box 26666, Sharjah (United Arab Emirates); CESR, Universite de Toulouse, CNRS, 9, Avenue du Colonel Roche, Boite Postal 4346, F-31028 Toulouse Cedex 4 (France); L.U.P.M., Universite Montpellier II, CNRS, Place Eugene Bataillon, F-34095 Montpellier (France); Hansen Experimental Physics Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, California 94305 (United States); Max Planck Institut fuer Extraterrestrische Physik, D-85741, Garching (Germany); Max Planck Institut fur Extraterrestrische Physik, Garching, D-85741 Germany, and MPI Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Muenchen (Germany)

    2011-07-01

    The first {gamma}-ray line originating from outside the Solar System that was ever detected is the 511 keV emission from positron annihilation in the Galaxy. Despite 30 years of intense theoretical and observational investigation, the main sources of positrons have not been identified up to now. Observations in the 1990s with OSSE/CGRO (Oriented Scintillation Spectrometer Experiment on GRO satellite/Compton Gamma Ray Observatory) showed that the emission is strongly concentrated toward the Galactic bulge. In the 2000s, the spectrometer SPI aboard the European Space Agency's (ESA) International Gamma Ray Astrophysics Laboratory (INTEGRAL) allowed scientists to measure that emission across the entire Galaxy, revealing that the bulge-to-disk luminosity ratio is larger than observed at any other wavelength. This mapping prompted a number of novel explanations, including rather ''exotic'' ones (e.g., dark matter annihilation). However, conventional astrophysical sources, such as type Ia supernovae, microquasars, or x-ray binaries, are still plausible candidates for a large fraction of the observed total 511 keV emission of the bulge. A closer study of the subject reveals new layers of complexity, since positrons may propagate far away from their production sites, making it difficult to infer the underlying source distribution from the observed map of 511 keV emission. However, in contrast to the rather well-understood propagation of high-energy (>GeV) particles of Galactic cosmic rays, understanding the propagation of low-energy ({approx}MeV) positrons in the turbulent, magnetized interstellar medium still remains a formidable challenge. The spectral and imaging properties of the observed 511 keV emission are reviewed and candidate positron sources and models of positron propagation in the Galaxy are critically discussed.

  8. Value of positron emission tomography and computer tomography (PET/CT) for urologic malignancies

    International Nuclear Information System (INIS)

    Positron emission tomography is a functional imaging technique that allows the detection of the regional metabolic rate, and is often coupled with other morphological imaging technique such as computed tomography. The rationale for its use is based on the clearly demonstrated fact that functional changes in tumor processes happen before morphological changes. Its introduction to the clinical practice added a new dimension in conventional imaging techniques. This review presents the current and proposed indications of the use of positron emission/computed tomography for prostate, bladder and testes, and the potential role of this exam in radiotherapy planning. (authors)

  9. [Value of positron emission tomography and computer tomography (PET/CT) for urologic malignancies].

    Science.gov (United States)

    Boujelbene, N; Prior, J O; Boubaker, A; Azria, D; Schaffer, M; Gez, E; Jichlinski, P; Meuwly, J-Y; Mirimanoff, R O; Ozsahin, M; Zouhair, A

    2011-07-01

    Positron emission tomography is a functional imaging technique that allows the detection of the regional metabolic rate, and is often coupled with other morphological imaging technique such as computed tomography. The rationale for its use is based on the clearly demonstrated fact that functional changes in tumor processes happen before morphological changes. Its introduction to the clinical practice added a new dimension in conventional imaging techniques. This review presents the current and proposed indications of the use of positron emission/computed tomography for prostate, bladder and testes, and the potential role of this exam in radiotherapy planning. PMID:21507695

  10. Analysis of local perfusion rate and local glucose transport rate in brain and heart in man by means of C-11-methyl-D-glucose and dynamic positron emission tomography

    International Nuclear Information System (INIS)

    Because an imbalance of perfusion, transport and metabolism may determine the ultimate damage in ischemic brain - or heart disease, it appears desirable to simultaneously determine the rates of regional perfusion and glucose utilisation, in small brain or heart regions. Local tissue perfusion rate (LPR) and unidirectional glucose transmembrane transport rate (LGTR) may be simultaneously assayed by C-11-labelled methyl-D-glucose (CMG). This sugar analogue follows the pathway of glucose via perfusion and transmembrane transport, yet does not enter cellular metabolism; it returns to blood. Following intravenous application, CMG equilibrates between blood and tissue. The CMG concentration in blood (csub(B)) at various times may be taken as internal standard, against which the tracer accumulation in tissue is evaluated. 2-5 mCi of CMG were injected into an antecubital vein of the patient and transaxial activity distribution in one selected slice of brain or chest was registered with the ECAT II scanner at 2 minute intervals for 40 minutes. The measured attenuation correction was used for image reconstruction. Different regions of brain or heart scans were then selected and time activity curves created. The data from sup. long. sinus (brain) and left ventricular cavity (heart) were taken to represent csub(B). It was concluded from the data that for diagnostic evaluation of ultimate brain or heart damage simultaneous quantitative assessment of both LPR or LGTR is of basic importance. There is evidence that the CMG technique is an excellent tool which provide the possibility to obtain this information in defined morphological regions

  11. Positron emission tomography alone, positron emission tomography-computed tomography and computed tomography in diagnosing recurrent cervical carcinoma: a systematic review and meta-analysis

    OpenAIRE

    Xiao, Yi; Wei, Jia; Zhang, Yicheng; Xiong, Weining

    2014-01-01

    Introduction The aim of the study was to assess systematically the accuracies of positron emission tomography (PET), PET/computed tomography (CT), and CT in diagnosing recurrent cervical cancer. Material and methods We searched for articles published from January 1980 to June 2013 using the following inclusion criteria: articles were reported in English; the use of PET, interpreted with or without the use of CT; use of CT to detect recurrent cervical cancer; and histopathologic analysis and/o...

  12. Imaging Spectrum and Pitfalls of 11C-Methionine Positron Emission Tomography in a Series of Patients with Intracranial Lesions

    Science.gov (United States)

    Matsuda, Hiroshi; Kubota, Kazoo

    2016-01-01

    11C-methionine (Met) positron emission tomography (PET) is one of the most commonly used PET tracers for evaluating brain tumors. However, few reports have described tips and pitfalls of 11C-Met PET for general practitioners. Physiological 11C-Met uptake, anatomical variations, vascular disorders, non-tumorous lesions such as inflammation or dysplasia, benign brain tumors and patient condition during 11C-Met PET examination can potentially affect the image interpretation and cause false positives and negatives. These pitfalls in the interpretation of 11C-Met PET images are important for not only nuclear medicine physicians but also general radiologists. Familiarity with the spectrum and pitfalls of 11C-Met images could help prevent unfavorable clinical results caused by misdiagnoses. PMID:27134530

  13. Cerebral metabolic rates for glucose in mood disorders. Studies with positron emission tomography and fluorodeoxyglucose F 18

    International Nuclear Information System (INIS)

    Cerebral metabolic rates for glucose were examined in patients with unipolar depression (N = 11), bipolar depression (N = 5), mania (N = 5), bipolar mixed states (N = 3), and in normal controls (N = 9) using positron emission tomography and fluorodeoxyglucose F 18. All subjects were studied supine under ambient room conditions with eyes open. Bipolar depressed and mixed patients had supratentorial whole brain glucose metabolic rates that were significantly lower than those of the other comparison groups. The whole brain metabolic rates for patients with bipolar depression increased going from depression or a mixed state to a euthymic or manic state. Patients with unipolar depression showed a significantly lower ratio of the metabolic rate of the caudate nucleus, divided by that of the hemisphere as a whole, when compared with normal controls and patients with bipolar depression

  14. Methodology of the individual detection of cerebral activations by positrons emission tomography: statistical characterization of noise images and introduction of anatomical information

    International Nuclear Information System (INIS)

    The work that presented here has been done in the context of non invasive study of human brain, with metabolism images techniques ( positrons emission tomography or P.E.T.) and anatomy images techniques (imaging by nuclear magnetic resonance or MRI). The objective of this thesis was to use jointly, the information given by these two ways, in the aim of improving the individual detection of cerebral activation. (N.C.)

  15. Increased neurokinin-1 receptor availability in the amygdala in social anxiety disorder : a positron emission tomography study with [(11)C]GR205171

    OpenAIRE

    Frick, Andreas; Åhs, Fredrik; Linnman, Clas; Jonasson, My; Appel, Lieuwe; Lubberink, Mark; Långström, Bengt; Fredrikson, Mats; Furmark, Tomas

    2015-01-01

    The neurokinin-1 (NK1) receptor is abundantly expressed in the fear circuitry of the brain, including the amygdala, where it modulates stress and anxiety. Despite its proposed involvement in psychopathology, only a few studies of NK1 receptor availability in human subjects with anxiety disorders exist. Here, we compared NK1 receptor availability in patients with social anxiety disorder (SAD; n = 17) and healthy controls (n = 17) using positron emission tomography and the radiotracer [(11)C]GR...

  16. The electronics system for the LBNL positron emission tomography (PEM) camera

    International Nuclear Information System (INIS)

    We describe the electronics for a high performance Positron Emission Mammography (PEM) camera. It is based on the electronics for a human brain PET camera (the Siemens/CTI HRRT), modified to use a detector module that incorporates a photodiode (PD) array. An ASIC services the PD array, amplifying its signal and identifying the crystal of interaction. Another ASIC services the photomultiplier tube (PMT), measuring its output and providing a timing signal. Field programmable gate arrays (FPGAs) and lookup RAMs are used to apply crystal by crystal correction factors and measure the energy deposit and the interaction depth (based on the PD/PMT ratio). Additional FPGAs provide event multiplexing, derandomization, coincidence detection, and real-time rebinning. Embedded PC/104 microprocessors provide communication, real-time control, and configure the system. Extensive use of FPGAs makes the overall design extremely flexible, allowing many different functions (or design modifications) to be realized without hardware changes. Incorporation of extensive onboard diagnostics, implemented in the FPGAs, is required by the very high level of integration and density achieved by this system

  17. Detection of amyloid in Alzheimer's disease with positron emission tomography using [11C]AZD2184

    International Nuclear Information System (INIS)

    Current positron emission tomography (PET) radioligands for detection of Aβ amyloid in Alzheimer's disease (AD) are not ideal for quantification. To improve the signal to noise ratio we have developed the radioligand [11C]AZD2184 and report here the first clinical evaluation. Eight AD patients and four younger control subjects underwent 93-min PET measurements with [11C]AZD2184. A ratio approach using the cerebellum as reference region was applied to determine binding parameters. Brain uptake of [11C]AZD2184 peaked within 1 min at 3-4% of injected radioactivity. AD patients had high radioactivity in cortical regions while controls had uniformly low radioactivity uptake. Specific binding peaked within 30 min at which time standardized uptake value ratios (SUVR) ranged between 1.19 and 2.57. [11C]AZD2184 is a promising radioligand for detailed mapping of Aβ amyloid depositions in Alzheimer's disease, due to low non-specific binding, high signal to background ratio and reversible binding as evident from early peak equilibrium. (orig.)

  18. Cerebral hypometabolism in progressive supranuclear palsy studied with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Foster, N.L.; Gilman, S.; Berent, S.; Morin, E.M.; Brown, M.B.; Koeppe, R.A.

    1988-09-01

    Progressive supranuclear palsy (PSP) is characterized by supranuclear palsy of gaze, axial dystonia, bradykinesia, rigidity, and a progressive dementia. Pathological changes in this disorder are generally restricted to subcortical structures, yet the type and range of cognitive deficits suggest the involvement of many cerebral regions. We examined the extent of functional impairment to cerebral cortical and subcortical structures as measured by the level of glucose metabolic activity at rest. Fourteen patients with PSP were compared to 21 normal volunteers of similar age using 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography. Glucose metabolism was reduced in the caudate nucleus, putamen, thalamus, pons, and cerebral cortex, but not in the cerebellum in the patients with PSP as compared to the normal subjects. Analysis of individual brain regions revealed significant declines in cerebral glucose utilization in most regions throughout the cerebral cortex, particularly those in the superior half of the frontal lobe. Declines in the most affected regions of cerebral cortex were greater than those in any single subcortical structure. Although using conventional neuropathological techniques the cerebral cortex appears to be unaffected in PSP, significant and pervasive functional impairments in both cortical and subcortical structures are present. These observations help to account for the constellation of cognitive symptoms in individual patients with PSP and the difficulty encountered in identifying a characteristic psychometric profile for this group of patients.

  19. Radiopharmaceuticals for positron emission tomography investigations of Alzheimer's disease

    Energy Technology Data Exchange (ETDEWEB)

    Naagren, Kjell [Odense University Hospital, Department of Nuclear Medicine, PET and Cyclotron Unit, Odense C (Denmark); Halldin, Christer [Karolinska University Hospital Solna, Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Stockholm (Sweden); Rinne, Juha O. [Turku PET Centre, P.O. Box 52, Turku (Finland)

    2010-08-15

    Alzheimer's disease (AD) is a common degenerative neurological disease that is an increasing medical, economical, and social problem. There is evidence that a long ''asymptomatic'' phase of the disease exists where functional changes in the brain are present, but structural imaging for instance with magnetic resonance imaging remains normal. Positron emission tomography (PET) is one of the tools by which it is possible to explore changes in cerebral blood flow and metabolism and the functioning of different neurotransmitter systems. More recently, investigation of protein aggregations such as amyloid deposits or neurofibrillary tangles containing tau-protein has become possible. The purpose of this paper is to review the current knowledge on various {sup 18}F- and {sup 11}C-labelled PET tracers that could be used to study the pathophysiology of AD, to be used in the early or differential diagnosis or to be used in development of treatment and in monitoring of treatment effects. (orig.)

  20. Basic principles of positron emission tomography in oncology: Quantitation and whole body techniques

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) of the brain and heart has made important contributions in clinical and research applications in the fields of neurology and cardiology. The more recent applications of PET in tumor imaging has marked oncology as the next frontier in PET; however, the dilemma of rising health care cost will challenge the application of new technologies. This challenge can be approached by innovative and appropriate use of sophisticated technology in both the research and clinical realms. The current developments of PET imaging technology to accurately stage the extent of tumor, as well as monitor the effectiveness or ineffectiveness of new or current therapies will be an extremely valuable tool in research and in the cost effective management of cancer patients. In the future, the oncologist may be able to adjust the chemotherapy to the tumor response based on PET imaging. In other situations, PET may be able to predict that no existing therapy will elicit a durable response, resolving the patients and families uncertainty of whether extreme therapeutic measures would have made a significant difference. This paper reviews some of the recent developments and areas of research in tumor PET imaging, and describes some of the practical and technical aspects involved with FDG tumor quantitation and whole body PET imaging. (authors)

  1. Proximal methods for the resolution of inverse problems: application to positron emission tomography

    International Nuclear Information System (INIS)

    The objective of this work is to propose reliable, efficient and fast methods for minimizing convex criteria, that are found in inverse problems for imagery. We focus on restoration/reconstruction problems when data is degraded with both a linear operator and noise, where the latter is not assumed to be necessarily additive.The reliability of the method is ensured through the use of proximal algorithms, the convergence of which is guaranteed when a convex criterion is considered. Efficiency is sought through the choice of criteria adapted to the noise characteristics, the linear operators and the image specificities. Of particular interest are regularization terms based on total variation and/or sparsity of signal frame coefficients. As a consequence of the use of frames, two approaches are investigated, depending on whether the analysis or the synthesis formulation is chosen. Fast processing requirements lead us to consider proximal algorithms with a parallel structure. Theoretical results are illustrated on several large size inverse problems arising in image restoration, stereoscopy, multi-spectral imagery and decomposition into texture and geometry components. We focus on a particular application, namely Positron Emission Tomography (PET), which is particularly difficult because of the presence of a projection operator combined with Poisson noise, leading to highly corrupted data. To optimize the quality of the reconstruction, we make use of the spatio-temporal characteristics of brain tissue activity. (author)

  2. Positron emission tomography neuroimaging in amyotrophic lateral sclerosis: what is new?

    International Nuclear Information System (INIS)

    Amyotrophic lateral sclerosis (ALS) is a neuro degenerative disease involving upper and lower motor neurons, extra-motor neurons, microglia and astrocytes. The neuro degenerative process results in progressive muscle paralysis and even in cognitive impairment. Within the complex diagnostic work-up, positron emission tomography (PET) represents a valuable imaging tool in the assessment of patients with ALS. PET, by means of different radiotracers (i.e. 18F-fluorodeoxyglucose, 6-[18F]fluoro-L-dopa, [11C]flumazenil) can assess the status of the wide range of brain regions and neural circuits, which can be affected by ALS. Furthermore, experimental radio compounds have been developed for the evaluation of white matter, which plays a role in the progression of the disease. Here we present a comprehensive review including in different sections the most relevant PET studies: studies investigating ALS and ALS-mimicking conditions (especially primary lateral sclerosis and other neuro degenerative diseases), articles selecting specific subsets of patients (with bulbar or spinal onset), studies investigating patients with familial type of ALS, studies evaluating the role of the white matter in ALS and papers evaluating the diagnostic sensitivity of PET in ALS patients

  3. Cerebral hypometabolism in progressive supranuclear palsy studied with positron emission tomography

    International Nuclear Information System (INIS)

    Progressive supranuclear palsy (PSP) is characterized by supranuclear palsy of gaze, axial dystonia, bradykinesia, rigidity, and a progressive dementia. Pathological changes in this disorder are generally restricted to subcortical structures, yet the type and range of cognitive deficits suggest the involvement of many cerebral regions. We examined the extent of functional impairment to cerebral cortical and subcortical structures as measured by the level of glucose metabolic activity at rest. Fourteen patients with PSP were compared to 21 normal volunteers of similar age using 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography. Glucose metabolism was reduced in the caudate nucleus, putamen, thalamus, pons, and cerebral cortex, but not in the cerebellum in the patients with PSP as compared to the normal subjects. Analysis of individual brain regions revealed significant declines in cerebral glucose utilization in most regions throughout the cerebral cortex, particularly those in the superior half of the frontal lobe. Declines in the most affected regions of cerebral cortex were greater than those in any single subcortical structure. Although using conventional neuropathological techniques the cerebral cortex appears to be unaffected in PSP, significant and pervasive functional impairments in both cortical and subcortical structures are present. These observations help to account for the constellation of cognitive symptoms in individual patients with PSP and the difficulty encountered in identifying a characteristic psychometric profile for this group of patients

  4. Positron emission tomography neuroimaging in amyotrophic lateral sclerosis: what is new?

    Science.gov (United States)

    Quartuccio, N; Van Weehaeghe, D; Cistaro, A; Jonsson, C; Van Laere, K; Pagani, M

    2014-12-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease involving upper and lower motor neurons, extra-motor neurons, microglia and astrocytes. The neurodegenerative process results in progressive muscle paralysis and even in cognitive impairment. Within the complex diagnostic work-up, positron emission tomography (PET) represents a valuable imaging tool in the assessment of patients with ALS. PET, by means of different radiotracers (i.e. 18F-fluorodeoxyglucose, 6-[18F]fluoro-L-dopa, [11C]flumazenil) can assess the status of the wide range of brain regions and neural circuits, which can be affected by ALS. Furthermore, experimental radiocompounds have been developed for the evaluation of white matter, which plays a role in the progression of the disease. Here we present a comprehensive review including in different sections the most relevant PET studies: studies investigating ALS and ALS-mimicking conditions (especially primary lateral sclerosis and other neurodegenerative diseases), articles selecting specific subsets of patients (with bulbar or spinal onset), studies investigating patients with familial type of ALS, studies evaluating the role of the white matter in ALS and papers evaluating the diagnostic sensitivity of PET in ALS patients. PMID:25375229

  5. Pharmacological constraints associated with positron emission tomographic scanning of small laboratory animals

    International Nuclear Information System (INIS)

    With the stated aim of scanning small regions of interest in mice, several high-resolution positron emission tomographic (PET) systems are presently under development. Some, however, have low sensitivity and require high doses of radioactivity to achieve count statistics adequate to reconstruct small volumes. Using in vivo dissociation constants for three carbon-11 labelled ligands previously measured in rat brain, the present paper utilises simple saturation kinetics to estimate the limits on radioactivity and specific activity, to minimise the degree of receptor occupancy and achieve maximal specific binding of the radioligand. The extent of the problem is exemplified by considering a high-affinity ligand (dissociation constant in vitro ∝0.1 nM; in vivo ∝5 nmol/kg i.v. injected dose), where routinely produced levels of specific activity (∝100 MBq/nmol) would limit the activity injected into mice to ∝0.1 MBq for a 1% receptor occupancy. If, as is feasible, the new generation of high resolution PET systems requires an injected activity >10 MBq, then a >100-fold increase in specific activity would be needed for tracer kinetics to hold. The paper highlights the need to consider realistically achievable goals if high-resolution PET is to be accepted as a viable methodology to acquire pharmacologically and physiologically accurate ligand-receptor binding data in mice. (orig.)

  6. A New Approach to Image Reconstruction in Positron Emission Tomography Using Artificial Neural Networks

    Science.gov (United States)

    Bevilacqua, A.; Bollini, D.; Campanini, R.; Lanconelli, N.; Galli, M.

    This study investigates the possibility of using an Artificial Neural Network (ANN) for reconstructing Positron Emission Tomography (PET) images. The network is trained with simulated data which include physical effects such as attenuation and scattering. Once the training ends, the weights of the network are held constant. The network is able to reconstruct every type of source distribution contained inside the area mapped during the learning. The reconstruction of a simulated brain phantom in a noiseless case shows an improvement if compared with Filtered Back-Projection reconstruction (FBP). In noisy cases there is still an improvement, even if we do not compensate for noise fluctuations. These results show that it is possible to reconstruct PET images using ANNs. Initially we used a Dec Alpha; then, due to the high data parallelism of this reconstruction problem, we ported the learning on a Quadrics (SIMD) machine, suited for the realization of a small medical dedicated system. These results encourage us to continue in further studies that will make possible reconstruction of images of bigger dimension than those used in the present work (32 × 32 pixels).

  7. Positron emission tomographic studies using C-11-glucose in normal aging and cerebrovascular dementia

    International Nuclear Information System (INIS)

    Seven normal volunteers and 11 patients with cerebrovascular dementia were studied about the relations between effect of aging, severity of dementia, cerebral glucose metabolism and metabolic response to verbal stimuli by positron emission tomography (PET) using C-11-glucose. Regional distribution of glycogenic metabolites (RDGM: mg/100 g brain), which was a semi-quantitation of the pool of glycogenic metabolites mainly amino acids, were calculated. The RDGM values in elder normal subjects were significantly low compared with young normal subjects in frontal cortex (p < 0.05). The decline in frontal cortex metabolism could have been caused by the morphological changes in the course of aging. In temporal cortex, there was no significance between two groups. RDGM increased significantly respond to the verbal stimuli in frontal and temporal cortex both young and elder normal subjects. The RDGM values in vascular dementias were significantly low (p < 0.001) compared with elder normal subjects' in frontal and temporal cortex. Significant difference existed between mild and severe dementia in frontal cortex (p < 0.05). However, there was no significance between mild and severe dementias in temporal cortex. In mild dementias, RDGM increased significantly respond to the verbal stimuli in frontal and temporal cortex. In severe dementias, metabolic response to the verbal stimuli was less or lacking. Our results suggest that the cerebral metabolic functional reserve and the ability of the cerebral cortex to function respond to psychophysiologic stimulation are preserved in young and elder normal subjects and mild cerebrovascular dementias. (J.P.N.)

  8. Active transport of C-11-Methyl-D-Glucose and 3-F-18-Deoxyglucose in acute ischemic brain disease and Huntington's chorea, studied by positron-emission-tomography (PET)

    International Nuclear Information System (INIS)

    C-11-Methyl-D-Glucose (CMG) and 3-F-18-Deoxyglucose (3FDG) were demonstrated to be non-metabolizable glucose analogues which are transported across the blood-brain-barrier into and out of tissue via the glucose carrier system (GCS). These two substances were used as indicators for determining the perfusion-independent rate constant of GCS in the brain. Five normals with informed consent, 12 patients with acute ischemic brain disease and 9 patients with initial and advanced Huntington's chorea were examined by PET after i.v. application of 5 mCi of GMG or 3FDG. In each patient 30 transaxial images were registered in 1 selected plane, image collection time being 1 min. Time-activity curves were created from different regions of interest. The slope to tracer steady state between tissue and blood yields the perfusion-independent rate constant of GCS from tissue to blood (k/sub 2/). In normals k/sub 2/ for CMG was 0.235 +- 0.03/min, as expected, and for 3FDG 0.47 +- 0.07/min indicating a higher affinity to GCS for 3FDG than CMG. In acute ischemic brain disease k/sub 2/ was normal or reduced at the site of insult for both CMG and 3FDG. In Huntington's chorea, k/sub 2/ was reduced in the basal ganglia but normal or occasionally significantly increased in frontal or occipital cortical areas, for CMG and 3FDG. The authors conclude that CMG permits noninvasive analysis of the perfusion-independent rate constant of CCS. 3FDG shows a higher affinity for CCS than CMC but gives comparable information

  9. Depressed cerebral oxygen metabolism in patients with chronic renal failure. A positron emission tomography study

    International Nuclear Information System (INIS)

    In order to elucidate brain oxygen metabolism in uremic patients, the regional cerebral blood flow (rCBF), oxygen extraction (rOEF) and oxygen metabolism (rCMRO2) were measured by positron emission tomography (PET) in both 10 hemodialysis patients (HD: male [m]/female [f]=2/8, age of 49±3 [SEM] years old, HD duration of 113±26 months) and 13 pre-dialysis renal failure patients (CRF: m/f=10/3, age of 61±2 years old, serum creatinine (SCr) of 6.3±1.0 mg/dl). Data were compared with 20 non-uremic subjects (Control: m/f=7/13, age of 62±2 years old, SCr of 0.9±0.1 mg/dl). They had no neurological abnormalities, congestive heart failure, history of cerebrovascular accident, diabetes mellitus, or symptomatic brain lesion on magnetic resonance imaging. The age of HD was significantly younger than the other groups (p2 in both HD (1.82±0.10 ml/min/100 g) and CRF (1.95±0.09) showed significantly lower values as compared to Control (2.23±0.05) (p<0.01, respectively). Hemispheric rCBF in HD (35.6±2.1 ml/100 g/min) and in CRF (36.1±2.1) were not different from that in Control (31.8±1.4). Hemispheric rOEF in CRF (45.7±1.6%) was significantly higher than that in Control (40.5±1.2%) (p<0.02), but that in HD (43.7±1.9%) did not increase significantly. These tendencies were similar in all regions of interest, especially in the cerebral cortices, but not in the cerebellum. All PET parameters in the frontal cortices tended to show the lowest value in renal failure patients. For all HD patients, rCBF in both the frontal cortex and the white matter correlated inversely with HD duration (frontal cortex: r=-0.649, p<0.05; white matter: r=-0.706, p<0.02). Based on these data, it is concluded that brain oxygen metabolism is depressed in renal failure patients on or before hemodialysis treatment. The cause for the depressed brain oxygen metabolism is considered to be due either to the dysregulation of cerebral circulation or to lower brain cell activity. (author)

  10. Cerebral metabolic data obtained by positron emission tomography in physiological aging. A review of the literature

    International Nuclear Information System (INIS)

    Following a summary of the general principles and limitations of metabolic measurements by positron emission tomography and of the different indices used to interpret the data, the authors review the results of published studies on physiological aging. Globally, with strict inclusion criteria absolute metabolic values at rest and under partial sensorial deprivation are little or not modified by age. In contrast, functional interactions between regions, as deduced from metabolic intercorrelations, are perhaps different in elderly people. In any case, positron emission tomography seems to discriminate between normal aging and different patterns of pathological aging. Technical improvements, more refined neuropsychological correlations and the use of dynamic activation paradigms will no doubt provide, in the future, a better definition of normal and pathological aging as positron tomography

  11. Cerebral metabolic data obtained by positron emission tomography in physiological aging. A review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Pellat, J.; Hommel, M.

    1987-06-18

    Following a summary of the general principles and limitations of metabolic measurements by positron emission tomography and of the different indices used to interpret the data, the authors review the results of published studies on physiological aging. Globally, with strict inclusion criteria absolute metabolic values at rest and under partial sensorial deprivation are little or not modified by age. In contrast, functional interactions between regions, as deduced from metabolic intercorrelations, are perhaps different in elderly people. In any case, positron emission tomography seems to discriminate between normal aging and different patterns of pathological aging. Technical improvements, more refined neuropsychological correlations and the use of dynamic activation paradigms will no doubt provide, in the future, a better definition of normal and pathological aging as positron tomography.

  12. Use of transputers in a 3-D positron emission tomograph

    International Nuclear Information System (INIS)

    This paper discusses the use of a VME-based transputer system as a front-end parallel processing engine for Positron Volume Imaging. The authors model different topologies with different numbers of nodes, using the Master/Worker software paradigm called a Processor Farm, and determine optimum configuration parameters for different computation requirements. The versatility and scalability of transputers makes them very suitable for use in PVI tomographs in that the same transputers can be used for speeding up data acquisition, image reconstruction and display

  13. Time resolution in scintillator based detectors for positron emission tomography

    International Nuclear Information System (INIS)

    In the domain of medical photon detectors L(Y)SO scintillators are used for positron emission tomography (PET). The interest for time of flight (TOF) in PET is increasing since measurements have shown that new crystals like L(Y)SO coupled to state of the art photodetectors, e.g. silicon photomultipliers (SiPM), can reach coincidence time resolutions (CTRs) of far below 500ps FWHM. To achieve these goals it is important to study the processe in the whole detection chain, i.e. the high energy particle or gamma interaction in the crystal, the scintillation process itself, the light propagation in the crystal with the light transfer to the photodetector, and the electronic readout. In this thesis time resolution measurements for a PET like system are performed in a coincidence setup utilizing the ultra fast amplifier discriminator NINO. We found that the time-over-threshold energy information provided by NINO shows a degradation in energy resolution for higher SiPM bias voltages. This is a consequence of the increasing dark count rate (DCR) of the SiPM with higher bias voltages together with the exponential decay of the signal. To overcome this problem and to operate the SiPM at its optimum voltage in terms of timing we developed a new electronic board that employs NINO only as a low noise leading edge discriminator together with an analog amplifier which delivers the energy information. With this new electronic board we indeed improved the measured CTR by about 15%. To study the limits of time resolution in more depth we measured the CTR with 2x2x3mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially available SiPMs (Hamamatsu S10931-50P MPPC) and achieved a CTR of 108±5ps FWHM at an energy of 511keV. We determined the influence of the data acquisition system and the electronics on the CTR to be 27±2ps FWHM and thus negligible. To quantitatively understand the measured values, we developed a Monte Carlo simulation tool in MATLAB that incorporates the timing

  14. Analysis of local perfusion rate (LPR) and local glucose transport rate (LGTR) in brain and heart in man by means of C-11-methyl-D-glucose (CMG) and dynamic positron emission tomography (dPET)

    International Nuclear Information System (INIS)

    A method has been developed to measure simultaneously the LPR and LGTR. CMG is used as an indicator. The transaxial distribution of activity in organism is registered with dPET. On the basis of a mathematical model, the LPR and LGTR can be calculated in terms of parameters of the time activity curves registered over different brain or heart regions and over the sup. long. sinus (brain) or the ventricular cavity (heart) (blood activity). The method was used in 10 normal subjects and 20 patients with ischemic brain or heart disease. The values of LGTR range from 0.43 to 0.6 μmol/min g in normal cortex and from 0.09 to 0.12 μmol/min g in normal white matter. The LPR was 0.9-098 ml/min g for the cortex and 0.3-0.4 ml/min g for the white matter. In patients with stroke the ischemic defects appeared to be larger in CMG scans than in CT. The results obtained in a patient with left homonymous hemianopia, caused by infarctions in the distribution area of RMCA, and in a patient with TIA, demonstrate that the inactivation of morphologically intact, cerebral cortex, observed in stroke patients, may be caused by undercutting of cortical fiber tracts as well as by the impairment of the glucose transport systems in the inactivated area. In myocardial studies the LPR in normal left myocardium was 0.68 ml/min g (subendocardium 0.74 ml/min g; subepicardiuim 0.65 ml/min g). In patients with old myocardial infarction, the infarcted areas could be easily recognized as accumulation defects. The results obtained in a patient with narrowing of the RCA indicate that repeated exposure of myocardial tissue to transient ischemia produces an irreversible damage of the glucose transport system. We conclude from the data that for diagnostic evaluation of ultimate brain or heart damage simultaneous quantitative assessment of both LPR and LGTR is of basic importance. (Author)

  15. Positron emission tomography/computerized tomography imaging of multiple focus of neurolymphomatosis

    International Nuclear Information System (INIS)

    Neurolymphomatosis is defined as infiltration of the peripheral nervous system by malignant lymphocytes in the presence of lymphoma. In this case, we described multiple neurol involvement and findings of 18F-fluorodeoxyglucose positron emission tomography/computerized tomography in a 35-year-old female diagnosed with B-cell lymphoma

  16. Recurrent ovarian endodermal sinus tumor: demonstration by computed tomography, magnetic resonance imaging, and positron emission tomography

    International Nuclear Information System (INIS)

    We report a case of recurrent endodermal sinus tumor of the ovary that was identified and/or clearly depicted by computed tomography, magnetic resonance imaging, and positron emission tomography. The potential roles of various imaging modalities in the detection of recurrent endodermal sinus tumor are discussed. (orig.)

  17. Fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography in evaluation of residual intramuscular myxoma

    International Nuclear Information System (INIS)

    Intramuscular myxoma (IM) is a rare benign neoplasm. In a patient diagnosed with IM of left thigh, we report the utility of a postoperative fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography scan in assessing the efficacy of surgical excision

  18. Monitoring liver tumor therapy with [18F]FDG positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) with [18F]-2-flurodeoxy-glucose (FDG) can be utilized as a functional imaging modality for monitoring liver tumor therapy. We report three cases in which PET-FDG was more useful for this purpose than other imaging methods and tumor markers

  19. Tomography by positrons emission: integral unit to the service of Mexico

    International Nuclear Information System (INIS)

    The applications of the Positron emission tomography (PET) together with the one radiopharmaceutical 2 - [18 F]-fluoro-2-deoxy-D-glucose in the area of the medical imaging is expanding quickly and it possesses a bigger impact at the moment in favor of those patient to who suffers an oncological, cardiac or neurological illness in Mexico. (Author)

  20. On the possible mixing of the electron capture and the positron emission channels in nuclear decay

    OpenAIRE

    Isakov, V. I.

    2009-01-01

    On the basis of the idea of mixing (interaction) between the electron capture and the positron emission channels in the \\beta^+ decay in the cases when both channels are energetically allowed, we attempt to explain oscillations of the K-capture rates that were possibly seen in the recent experiment.

  1. Positron emission tomography-computed tomography has a clinical impact for patients with cervical cancer

    DEFF Research Database (Denmark)

    Sandvik, Rikke Mulvad; Jensen, Pernille Tine; Hendel, Helle Westergren;

    2011-01-01

    Many studies have found that positron emission tomography-computed tomography (PET-CT) has a high sensitivity and specificity in the identification of metastasis in cervical cancer. Herlev Hospital, Denmark, has been performing PET-CTs in stage I-IV cervical cancer since 1 May 2006. The present...

  2. Small animal positron emission tomography imaging and in vivo studies of atherosclerosis

    DEFF Research Database (Denmark)

    Hag, Anne Mette Fisker; Ripa, Rasmus Sejersten; Pedersen, Sune Folke;

    2013-01-01

    Atherosclerosis is a growing health challenge globally, and despite our knowledge of the disease has increased over the last couple of decades, many unanswered questions remain. As molecular imaging can be used to visualize, characterize and measure biological processes at the molecular and cellu...... knowledge obtained from in vivo positron emission tomography studies of atherosclerosis performed in small animals....

  3. Characterisation of beta(2)-adrenoceptors, using the agonist [C-11]formoterol and positron emission tomography

    NARCIS (Netherlands)

    Visser, T.J; van Waarde, Aaren; Doze, P; Elsinga, P.H; van der Mark, Thomas W.; Kraan, Jan; Ensing, Kees; Vaalburg, W.

    1998-01-01

    The agonist radioligand N-[2-hydroxy-5-[1-hydroxy-2-[[2-(4-[C-11]-methoxyphenyl)-1-methylethyl]amino]ethyl]phenyl]formamide ([C-11]formoterol) was synthesised in order to test its ability to visualise pulmonary beta(2)-adrenoceptors in vivo, with positron emission tomography (PET). Formoterol was la

  4. Capillaries within compartments: microvascular interpretation of dynamic positron emission tomography data

    DEFF Research Database (Denmark)

    Munk, O L; Keiding, S; Bass, L

    2003-01-01

    Measurement of exchange of substances between blood and tissue has been a long-lasting challenge to physiologists, and considerable theoretical and experimental accomplishments were achieved before the development of the positron emission tomography (PET). Today, when modeling data from modern PE...

  5. Diffuse nesidioblastosis diagnosed on a Ga-68 DOTATATE positron emission tomography/computerized tomography.

    Science.gov (United States)

    Arun, Sasikumar; Rai Mittal, Bhagwant; Shukla, Jaya; Bhattacharya, Anish; Kumar, Praveen

    2013-07-01

    The authors describe a 50 days old pre-term infant with persistent hyperinsulinemic hypoglycemia of infancy in whom Ga-68 DOTATATE positron emission tomography/computerized tomography scan showed diffusely increased tracer uptake in the entire pancreas with no abnormal tracer uptake anywhere else in the body, suggestive of a diffuse variant of nesidioblastosis. PMID:24250024

  6. a Dynamic Technique for the Quantitation of Oxygen Utilization Rates Using Positron Emission Tomography

    Science.gov (United States)

    Hutchins, Gary Dwight

    The conversion of oxygen to water in oxidative phosphorylation is required for the efficient production of adenosine triphosphate. This process can be monitored externally using oxygen-15 and positron emission tomography to allow estimation of metabolic rate in the human brain. A dynamic technique using ('15)O-O(,2) has been developed and compared to the existing steady state and autoradiographic approaches. These currently employed methods suffer from pitfalls associated with using assumed values for the tissue -blood partition coefficient of water. Computer simulations have been performed demonstrating the underestimation of physiological rates with the steady state technique and the time varying solutions of the autoradiographic approach. Experimental data agrees with the predicted behavior of each of these methods. The new technique requires the estimation of local cerebral blood volume and the tissue-blood partition coefficient value of water. The blood volume, necessary for a blood radioactivity correction, is estimated from the equilibrium distribution of ('15)O-CO. The tissue-blood partition coefficient is calculated using a rapid least squares analysis of ('15)O-H(,2)O dynamic blood flow data. The measured values of blood volume and partition coefficient are assumed to remain invariant with changes in the physiological state of the brain. The metabolic rate is then estimated by fitting the oxygen model to the observed kinetics in a one minute breathhold study. Alternatives to arterial blood sampling have been considered. Expired breath and lung activity concentrations used in conjunction with arterial blood sample data provide the required input functions. A time-of-flight probe has been developed as a non-invasive alternative and some intial measurements with the system are presented. The experimental data are in good agreement with the model predictions supporting the switch to a dynamic technique for the estimation of oxygen utilization rate using ('15

  7. Positron emission imaging device and method of using the same

    Science.gov (United States)

    Bingham, Philip R.; Mullens, James Allen

    2013-01-15

    An imaging system and method of imaging are disclosed. The imaging system can include an external radiation source producing pairs of substantially simultaneous radiation emissions of a picturization emission and a verification emissions at an emission angle. The imaging system can also include a plurality of picturization sensors and at least one verification sensor for detecting the picturization and verification emissions, respectively. The imaging system also includes an object stage is arranged such that a picturization emission can pass through an object supported on said object stage before being detected by one of said plurality of picturization sensors. A coincidence system and a reconstruction system can also be included. The coincidence can receive information from the picturization and verification sensors and determine whether a detected picturization emission is direct radiation or scattered radiation. The reconstruction system can produce a multi-dimensional representation of an object imaged with the imaging system.

  8. The review of myocardial positron emission computed tomography and positron imaging by gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, Tohru [Tokyo Univ. (Japan). Faculty of Medicine

    1998-04-01

    To measure myocardial blood flow, Nitrogen-13 ammonia, Oxygen-15 water, Rubidium-82 and et al. are used. Each has merit and demerit. By measuring myocardial coronary flow reserve, the decrease of flow reserve during dipyridamole in patients with hypercholesterolemia or diabetes mellitus without significant coronary stenosis was observed. The possibility of early detection of atherosclerosis was showed. As to myocardial metabolism, glucose metabolism is measured by Fluorine-18 fluorodeoxyglucose (FDG), and it is considered as useful for the evaluation of myocardial viability. We are using FDG to evaluate insulin resistance during insulin clamp in patients with diabetes mellitus by measuring glucose utilization rate of myocardium and skeletal muscle. FFA metabolism has been measured by {sup 11}C-palmitate, but absolute quantification has not been performed. Recently the method for absolute quantification was reported, and new radiopharmaceutical {sup 18}F-FTHA was reported. Oxygen metabolism has been estimated by {sup 11}C-acetate. Myocardial viability, cardiac efficiency was evaluated by oxygen metabolism. As to receptor or sympathetic nerve end, cardiac insufficiency or cardiac transplantation was evaluated. Imaging of positron emitting radiopharmaceutical by gamma camera has been performed. Collimator method is clinically useful for cardiac imaging of viability study. (author). 54 refs.

  9. The review of myocardial positron emission computed tomography and positron imaging by gamma camera

    International Nuclear Information System (INIS)

    To measure myocardial blood flow, Nitrogen-13 ammonia, Oxygen-15 water, Rubidium-82 and et al. are used. Each has merit and demerit. By measuring myocardial coronary flow reserve, the decrease of flow reserve during dipyridamole in patients with hypercholesterolemia or diabetes mellitus without significant coronary stenosis was observed. The possibility of early detection of atherosclerosis was showed. As to myocardial metabolism, glucose metabolism is measured by Fluorine-18 fluorodeoxyglucose (FDG), and it is considered as useful for the evaluation of myocardial viability. We are using FDG to evaluate insulin resistance during insulin clamp in patients with diabetes mellitus by measuring glucose utilization rate of myocardium and skeletal muscle. FFA metabolism has been measured by 11C-palmitate, but absolute quantification has not been performed. Recently the method for absolute quantification was reported, and new radiopharmaceutical 18F-FTHA was reported. Oxygen metabolism has been estimated by 11C-acetate. Myocardial viability, cardiac efficiency was evaluated by oxygen metabolism. As to receptor or sympathetic nerve end, cardiac insufficiency or cardiac transplantation was evaluated. Imaging of positron emitting radiopharmaceutical by gamma camera has been performed. Collimator method is clinically useful for cardiac imaging of viability study. (author). 54 refs

  10. Methodological aspects in quantitative translational neuroimaging in central nervous system diseases with Positron Emission Tomography

    International Nuclear Information System (INIS)

    Patients suffering from central nervous system (CNS) diseases crucially depend on a sufficient supply with CNS active drugs that help them to control and endure their illness. As the site of action of CNS drugs is in the brain, these substances need to pass the blood-brain barrier (BBB), a physiological barrier seperating the blood circulation and the brain. However, CNS drug treatment is often accompanied by pharmacoresistance (drug resistance). Multidrug transporters, such as permeable glycoprotein (Pgp) are responsible for a gradient dependent transport of substances over the BBB. Drug resistance is hypothesised as a result of overactivity of multidrug transporters at the BBB, with the result of insufficient and poor CNS drug levels in the brain. In the case of epilepsy in up to 20 - 40% of patients drug resistance is observed. The influence of Ppg overexpression on drug resistance in epilepsy was studied using positron emission tomography (PET), a novel non-invasive nuclear imaging method, together with radioligands that interact with Pgp. Radiolabeled Pgp-substrates ((R)-[11C]verapamil), and inhibitors ([11C]elacridar and [11C]tariquidar) were developed and used to study the influence of Pgp and other transporters at the BBB in a translational research approach; in animal models of epilepsy and in humans. The aim in translational PET research is a direct comparision of gathered animal and human data. Consequently diverse methodological challenges arise, that need to be addressed and observed in order to enable a translation between species. To achieve full quantification of the function and density of drug transporters at the BBB in both, humans and rodents, kinetic modeling (compartmental modeling) was applied to the PET pharmacokinetic data. Estimated modeling parameters were in succession used to estimate biological and physiological processes of Pgp at the BBB. Subsequently, nonlinear mixed effects modeling was deployed to increase the mechanistic

  11. Multitracer study with positron emission tomography in Creutzfeldt-Jakob disease

    Energy Technology Data Exchange (ETDEWEB)

    Engler, Henry [Uppsala University PET Centre, Uppsala University Hospital, SE 751 85 Uppsala (Sweden); Department of Neurology, Uppsala University Hospital, Uppsala (Sweden); Lundberg, Per Olov [Department of Neurology, Uppsala University Hospital, Uppsala (Sweden); Ekbom, Karl [Department of Neurology, Huddinge University Hospital, Stockholm (Sweden); Nennesmo, Inger [Department of Pathology, Huddinge University Hospital, Stockholm (Sweden); Nilsson, Anna; Bergstroem, Mats; Hartvig, Per; Laangstroem, Bengt [Uppsala University PET Centre, Uppsala University Hospital, SE 751 85 Uppsala (Sweden); Tsukada, Hideo [Hamamatsu Photonics K.K.Central Research Lab, Hamakita City (Japan)

    2003-01-01

    During the period February 1997 to April 2000, 15 patients with clinical symptoms of Creutzfeldt-Jakob disease (CJD) were referred to Uppsala University PET Centre. Positron emission tomography (PET) was performed to detect characteristic signs of the disease, e.g. neuronal death and/or astrocytosis in the brain. The examinations were performed in one session starting with oxygen-15 labelled water scan to measure regional cerebral blood flow, followed by imaging with the monoamine oxidase B inhibitor N-[{sup 11}C-methyl]-L-deuterodeprenyl (DED) to assess astrocytosis in the brain and finally imaging with fluorine-18 2-fluorodeoxyglucose (FDG) to assess regional cerebral glucose metabolism (rCMR{sub glu}). Nine of the patients fulfilled the clinical criteria of probable CJD. In eight of them, FDG and DED imaging revealed, in comparison with normal controls, a typical pattern characterized by a pronounced regional decrease (<2SD) in glucose brain metabolism, indicative of neuronal dysfunction; this was accompanied by a similar increase (>2SD) in DED binding, indicating astrocytosis. These changes were most pronounced in the cerebellum and the frontal, occipital and parietal cortices, whereas the pons, the thalamus and the putamen were less affected and the temporal cortex appeared unaffected. The cerebral blood flow showed a pattern similar to that observed with FDG. In the ninth patient, analysis with DED was not possible. The diagnosis of definite CJD according to international consensus criteria was confirmed in six of these patients. In one patient with probable CJD, protease-resistant prion protein (PrPres) could not be demonstrated. In two patients with probable CJD, autopsy was not allowed. Computed tomography and magnetic resonance imaging, performed in four and seven of these nine patients respectively, showed unspecific, mainly atrophic changes. In six other patients, the PET examinations gave a different pattern. In three of them, high rCMR{sub glu} was

  12. Three-dimensional imaging of hidden objects using positron emission backscatter

    International Nuclear Information System (INIS)

    Positron emission backscatter imaging is a technique for interrogation and three-dimensional (3-D) reconstruction of hidden objects when we only have access to the objects from one side. Using time-of-flight differences in detected direct and backscattered positron-emitted photons, we construct 3-D images of target objects. Recently at Los Alamos National Laboratory, a fully three-dimensional imaging system has been built and the experimental results are discussed in this paper. Quantitative analysis of images reconstructed in both two- and three-dimensions are also presented.

  13. Zolpidem-Induced Arousal by Paradoxical GABAergic Stimulation: A Case Report With F-18 Flumazenil Positron Emission Tomography and Single Photon Emission Computed Tomography Study

    Science.gov (United States)

    Kim, Changjae; Nam, Ki Yeun; Park, Jin Woo; Lee, Ho Jun

    2016-01-01

    Zolpidem is a non-benzodiazepine drug that has selectivity for the gamma-aminobutyric acid (GABA) receptors. We experienced paradoxical effect of zolpidem in a 48-year-old male patient with hypoxic-ischemic brain injury after cardiac arrest. The patient was in stupor and could not communicate. His Glasgow Coma Scale (GCS) was E2M4V2 and Rancho Los Amigos (RLA) was grade III to IV. Zolpidem was prescribed to induce sedation but paradoxically, he became alert (GCS 15, RLA VII) and was able to communicate. The arousal lasted for 2 hours repeatedly following each administration of the medication. While he was alert, electroencephalogram showed the reversal of slow wave into beta range fast activity and F-18 flumazenil positron emission tomography (PET) showed increased GABAergic receptor activity in both frontoparietotemporal cortices. Single photon emission computed tomography (SPECT) also showed increased cerebral perfusion and reversal of cerebellar diaschisis. PMID:26949686

  14. Regional cerebral metabolic alterations in dementia of the Alzheimer type: positron emission tomography with [18F]fluorodeoxyglucose

    International Nuclear Information System (INIS)

    Alzheimer disease is the most common cause of dementia in adults. Despite recent advances in our understanding of its anatomy and chemistry, we remain largely ignorant of its pathogenesis, physiology, diagnosis, and treatment. Dynamic positron emission tomography using [18F]fluorodeoxyglucose (FDG) was performed on the Donner 280-crystal ring in 10 subjects with dementia of the Alzheimer type and six healthy age-matched controls. Ratios comparing mean counts per resolution element in frontal, temporoparietal, and entire cortex regions in brain sections 10 mm thick obtained 40-70 min following FDG injection showed relatively less FDG uptake in the temporoparietal cortex bilaterally in all the Alzheimer subjects (p less than 0.01). Left-right alterations were less prominent than the anteroposterior changes. This diminished uptake was due to lowered rates of FDG use and suggests that the metabolic effects of Alzheimer disease are most concentrated in the temporoparietal cortex. Positron emission tomography is a most powerful tool for the noninvasive in vivo assessment of cerebral pathophysiology in dementia

  15. Gallium-68 ethylenediamine tetraacetic acid (EDTA) imaging of brain tumors by positron tomography

    International Nuclear Information System (INIS)

    While noncontrast CT demonstrates the effects of brain tumors, such as regions surrounding the tumors with low CT numbers, contrast is often required to show the tumor itself. Unfortunately, contrast may cause seizures in 9-15% of patients with brain metastases. Contrast enters the tumor region because of absence of the blood-brain barrier (BBB). Chelates have been used in planar nuclear imaging to study BBB integrity, but have not been used widely in position tomography. The authors carried out positron tomography (PET) with Ga-68 EDTA in 22 patients with suspected or proven brain tumors. In l3/22, the lesions were detected equally well by contract CT and PET. In 3/22 the lesions were more clearly visualized with PET than contrast CT. In 1 case, there as a more extensive abnormality on PET than on contract CT. In 2 post-operating patients, the presence of tumor was detected by contrast CT and PET, but interference from surgical clips obscured the CT but not the PET images. Indications for positron tomography with Ga-68 EDTA include allergy to contrast media, history of seizures with contrast media, or interfering opacities such as surgical clips or calcifications. An important characteristic of Ga-68 EDTA is that it is easily eluted from a long lived Ge-68 generator. Furthermore, GA-68 EDTA can be used to quantify BBB integrity with the appropriate modelling, e.g. as in steroid therapy

  16. Determination of the positron diffusion length in Kapton by analysing the positronium emission

    International Nuclear Information System (INIS)

    Doppler profile spectroscopy and Compton-to-peak ratio analysis have been used to study the positronium (Ps) emission from the Kapton surface as a function of the positron implantation energy E. Two different positions for the sample have been performed in the experiment. In the first case the sample and the Ge-detector are perpendicular to the positron beam. With this geometry the emission of para-positronium (p-Ps) is detected as a narrow central peak. In the second case, by rotating the sample 45 deg. with respect to the beam axis, the emission of p-Ps is detected as a blue-shifted fly away peak. The implantation of the positrons is described by the Makhov profile, where we used the modified median implantation for polymers as given by Algers et al. [J. Algers, P. Sperr, W. Egger, G. Koegel, F.H.J. Maurer, Phys. Rev. B 67 (2003) 125404]. Thermalised positrons can diffuse to the surface and may pick up an electron to be emitted as Ps. We found a thermal and or epithermal positron diffusion length L+ = 5.43 ± 0.71 nm and L+ = 5.51 ± 0.28 nm correspondingly for both cases, which is much more than the one found by Brusa et al. [R.S. Brusa, A. Dupasquier, E. Galvanetto, A. Zecca, Appl. Phys. A 54 (1992) 233]. The respective efficiency for the emission of Ps by picking up an electron from the surface is found to be fpu = 0.247 ± 0.012 and fpu = 0.156 ± 0.003

  17. A new method of detection for a positron emission tomograph using a time of flight method

    International Nuclear Information System (INIS)

    In the first chapter, it is shown the advantages of positron radioemitters (β+) of low period, and the essential characteristics of positron tomographs realized at the present time. The second chapter presents the interest of an original technique of image reconstruction: the time of flight technique. The third chapter describes the characterization methods which were set for verifying the feasibility of cesium fluoride in tomography. Chapter four presents the results obtained by these methods. It appears that the cesium fluoride constitute presently the best positron emission associated to time of flight technique. The hypotheses made on eventual performances of such machines are validated by experiments with phantom. The results obtained with a detector (bismuth germanate) conserves all its interest in skull tomography

  18. A new positron emission particle tracking facility at iThemba LABS

    International Nuclear Information System (INIS)

    Positron emission particle tracking (PEPT) has become a powerful tool for in-situ characterisation and visualization of particulate flow within aggressive industrial environments, such as tumbling mills and powder mixers. PEPT is based on the tracking of a single tracer particle which has been labelled with a radionuclide that decays via beta-plus decay. The location of the particle is obtained by the triangulation of events associated with the detection of pairs of annihilation gamma rays in a modified 'positron camera.' One of the challenges facing PEPT is associated with labelling particles smaller than 100 μm which would allow studies in systems of finer particulate flow, such as flotation cells. The Positron Imaging Centre at the University of Birmingham is currently the only operational PEPT facility in the world. PEPT Cape Town will shortly become operational at iThemba LABS, South Africa. (author)

  19. Multitracer study with positron emission tomography in Creutzfeldt-Jakob disease

    International Nuclear Information System (INIS)

    During the period February 1997 to April 2000, 15 patients with clinical symptoms of Creutzfeldt-Jakob disease (CJD) were referred to Uppsala University PET Centre. Positron emission tomography (PET) was performed to detect characteristic signs of the disease, e.g. neuronal death and/or astrocytosis in the brain. The examinations were performed in one session starting with oxygen-15 labelled water scan to measure regional cerebral blood flow, followed by imaging with the monoamine oxidase B inhibitor N-[11C-methyl]-L-deuterodeprenyl (DED) to assess astrocytosis in the brain and finally imaging with fluorine-18 2-fluorodeoxyglucose (FDG) to assess regional cerebral glucose metabolism (rCMRglu). Nine of the patients fulfilled the clinical criteria of probable CJD. In eight of them, FDG and DED imaging revealed, in comparison with normal controls, a typical pattern characterized by a pronounced regional decrease (2SD) in DED binding, indicating astrocytosis. These changes were most pronounced in the cerebellum and the frontal, occipital and parietal cortices, whereas the pons, the thalamus and the putamen were less affected and the temporal cortex appeared unaffected. The cerebral blood flow showed a pattern similar to that observed with FDG. In the ninth patient, analysis with DED was not possible. The diagnosis of definite CJD according to international consensus criteria was confirmed in six of these patients. In one patient with probable CJD, protease-resistant prion protein (PrPres) could not be demonstrated. In two patients with probable CJD, autopsy was not allowed. Computed tomography and magnetic resonance imaging, performed in four and seven of these nine patients respectively, showed unspecific, mainly atrophic changes. In six other patients, the PET examinations gave a different pattern. In three of them, high rCMRglu was noticed in parts of the brain, particularly in the temporal lobes and basal ganglia, which could suggest encephalitis. One of the

  20. Basal ganglia disorders studied by positron emission tomography

    International Nuclear Information System (INIS)

    Recent development of positron emitting radioligands has made it possible to investigate the alterations of neurotransmitter systems associated with basal ganglia disorders in vivo. The functional integrity of nigro-striatal dopaminergic terminals may be studied with [18F]6-fluoro-L-dopa ([18F]dopa), and striatal dopamine receptor density with suitable PET ligands. [18F]dopa uptake in the striatum (putamen) is markedly reduced in patients with Parkinson's disease (PD). [18F]dopa-PET is capable of detecting sub-clinical nigral dysfunction in asymptomatic patients with familial PD and those who become Parkinsonian on conventional doses of dopamine receptor antagonists. While putamen [18F]dopa uptake is reduced to a similar level in patients with multiple system atrophy (MSA) and PD, caudate [18F] dopa uptake is lower in MSA than PD. However, [18F]dopa PET cannot consistently distinguish MSA from PD because individual ranges of caudate [18F]dopa uptake overlap. D1 and D2 receptor binding is markedly reduced in the striatum (posterior putamen) of MSA patients. Therefore, dopamine receptor imaging is useful for the differential diagnosis of MSA and PD. Similar marked reductions in putamen and caudate [18F]dopa uptake have been observed in patients with progressive supranuclear palsy (PSP). Moderate reductions in D2 receptor binding have been reported in the striatum of PSP patients. The reduction in D2 receptor binding is more prominent in the caudate than putamen. Striatal [18F]dopa uptake is normal or only mildly reduced in patients with dopa responsive dystonia (DRD). D2 receptor binding is markedly reduced in patients with Huntington's disease, while striatal [18F]dopa uptake is normal or mildly reduced. In summary, PET can demonstrate characteristic patterns of disruption of dopaminergic systems associated with basal ganglia disorders. These PET findings are useful in the differential diagnosis of basal ganglia disorders. (J.P.N.) 55 refs

  1. What have positron emission tomography and 'Zippy' told us about the neuropharmacology of drug addiction?

    Science.gov (United States)

    Cumming, Paul; Caprioli, Daniele; Dalley, Jeffrey W

    2011-08-01

    Translational molecular imaging with positron emission tomography (PET) and allied technologies offer unrivalled applications in the discovery of biomarkers and aetiological mechanisms relevant to human disease. Foremost among clinical PET findings during the past two decades of addiction research is the seminal discovery of reduced dopamine D(2/3) receptor expression in the striatum of drug addicts, which could indicate a predisposing factor and/or compensatory reaction to the chronic abuse of stimulant drugs. In parallel, recent years have witnessed significant improvements in the performance of small animal tomographs (microPET) and a refinement of animal models of addiction based on clinically relevant diagnostic criteria. This review surveys the utility of PET in the elucidation of neuropharmacological mechanisms underlying drug addiction. It considers the consequences of chronic drug exposure on regional brain metabolism and neurotransmitter function and identifies those areas where further research is needed, especially concerning the implementation of PET tracers targeting neurotransmitter systems other than dopamine, which increasingly have been implicated in the pathophysiology of drug addiction. In addition, this review considers the causal effects of behavioural traits such as impulsivity and novelty/sensation-seeking on the emergence of compulsive drug-taking. Previous research indicates that spontaneously high-impulsive rats--as exemplified by 'Zippy'--are pre-disposed to escalate intravenous cocaine self-administration, and subsequently to develop compulsive drug taking tendencies that endure despite concurrent adverse consequences of such behaviour, just as in human addiction. The discovery using microPET of pre-existing differences in dopamine D(2/3) receptor expression in the striatum of high-impulsive rats suggests a neural endophenotype that may likewise pre-dispose to stimulant addiction in humans. PMID:20846139

  2. Human cerebral acetylcholinesterase activity measured with positron emission tomography: procedure, normal values and effect of age

    International Nuclear Information System (INIS)

    The regional cerebral metabolic rate of [11C]N-methyl-4-piperidyl acetate, which is nearly proportional to regional cerebral acetylcholinesterase (AChE) activity, was measured by dynamic positron emission tomography in 20 healthy subjects with a wide age range (24-89 years). Quantitative measurement was achieved using a kinetic model which consisted of arterial plasma and cerebral tissue compartments. The plasma input function was obtained using thin-layer chromatography and an imaging phosphor plate system at frequent sampling intervals to catch the rapid metabolism of the tracer in the blood. The distribution of the rate constant k3, an index of AChE activity, agreed well with reported post-mortem AChE distribution in the cerebral cortex (0.067-0.097 min-1) and thalamus (0.268 min-1), where AChE activity was low to moderate. The k3 values in the striatum and cerebellum, where AChE activity was very high, did not respond linearly to AChE activity because of increased flow dependency. No significant effect of age was found on AChE activity of the cerebral cortex, suggesting that the ascending central cholinergic system is preserved in normal aging. This study has shown that quantitative measurement of enzyme activity in the living brain is possible through appropriate modelling of tracer kinetics and accurate measurement of the input function. The method should be applicable to patients with Alzheimer's disease and those with other kinds of dementia whose central cholinergic system has been reported to be disturbed. (orig.)

  3. Human cerebral acetylcholinesterase activity measured with positron emission tomography: procedure, normal values and effect of age

    Energy Technology Data Exchange (ETDEWEB)

    Namba, Hiroki [Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan)]|[Division of Neurological Surgery, Chiba Cancer Center, Chiba (Japan); Iyo, Masaomi [Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan)]|[Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu (Japan); Fukushi, Kiyoshi; Suhara, Tetsuya; Sudo, Yasuhiko; Suzuki, Kazutoshi; Irie, Toshiaki [Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan); Shinotoh, Hitoshi [Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan)]|[Department of Neurology, Chiba University School of Medicine, Chiba (Japan); Nagatsuka, Shin-ichiro [Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan)]|[Tokai Research Laboratories, Daiichi Pure Chemical Co., Ltd., Ibaraki (Japan)

    1999-02-01

    The regional cerebral metabolic rate of [{sup 11}C]N-methyl-4-piperidyl acetate, which is nearly proportional to regional cerebral acetylcholinesterase (AChE) activity, was measured by dynamic positron emission tomography in 20 healthy subjects with a wide age range (24-89 years). Quantitative measurement was achieved using a kinetic model which consisted of arterial plasma and cerebral tissue compartments. The plasma input function was obtained using thin-layer chromatography and an imaging phosphor plate system at frequent sampling intervals to catch the rapid metabolism of the tracer in the blood. The distribution of the rate constant k{sub 3}, an index of AChE activity, agreed well with reported post-mortem AChE distribution in the cerebral cortex (0.067-0.097 min{sup -1}) and thalamus (0.268 min{sup -1}), where AChE activity was low to moderate. The k{sub 3} values in the striatum and cerebellum, where AChE activity was very high, did not respond linearly to AChE activity because of increased flow dependency. No significant effect of age was found on AChE activity of the cerebral cortex, suggesting that the ascending central cholinergic system is preserved in normal aging. This study has shown that quantitative measurement of enzyme activity in the living brain is possible through appropriate modelling of tracer kinetics and accurate measurement of the input function. The method should be applicable to patients with Alzheimer`s disease and those with other kinds of dementia whose central cholinergic system has been reported to be disturbed. (orig.) With 8 figs., 1 tab., 21 refs.

  4. Comparison study of positron emission tomography, X-ray CT and MRI in Parkinsonism with dementia

    International Nuclear Information System (INIS)

    Brain atrophy and local cerebral metabolic rate of glucose (LCMR-glc) in Parkinson's disease with dementia and Parkinsonism-dementia complex (PDC) were studied using positron emission tomography (PET) with F-18-2-deoxy-2-fluoro-D-glucose, X-ray CT and magnetic resonance imaging (MRI). The group of Parkinson's disease with dementia (n=7) had a significantly decreased LCMR-glc in all regions when compared with the age-matched normal group. In the group of Parkinson's disease without dementia (n=6), LCMR-glc was also significantly lower than the control group, although it was higher than the group with associated dementia. Some of the normal aged persons had cortical atrophy. There was no correlation between LCMR-glc and cortical atrophy. Six Guamnian patients had PDC associated with amyotrophic lateral sclerosis (ALS), and four patients had it without ALS. LCMR-glc did not differ in the two groups. It was, however, significantly lower than that in 5 Guamanian and 10 Caucasian normal persons. The group of PDC had a noticeable cortical atrophy and ventricular dilatation, regardless of the presence or absence of ALS. There was correlation between decrease of LCMR-glc and cortical atrophy of the frontal, parietal and temporal lobes. Parkinson's disease and PDC were different from Alzheimer's disease in which a decreased LCMR-glc has been reported to be usually confined to the cerebral cortex. Cortical atrophy and ventricular dilatation were depicted on MRI and CT in the PDC group, but did not in the group of Parkinson's disease. PET was useful in the functional examination and both MRI and CT were useful in the anatomical examination of these diseases. (Namekawa, K)

  5. A study of conduction aphasia by positron emission tomography

    International Nuclear Information System (INIS)

    We reported two cases of conduction aphasia with distinctive language disorder from early stage of stroke, as well as their cerebral blood flow and oxygen consumption investigated with PET. The case was a 72-year-old right handed man whose speech disturbance began acutely. On admission, neurological examination revealed hand pronation sign on the right and speech disturbance. Other neurological findings including cortical functions were normal. Brain CT scan showed low density area in the white matter of the left supramarginal gyrus. The diagnosis was cerebral infarction. The case 2 was a 64-year-old right handed man. He suffered right hemiparesis 2 months before. Neurological examination revealed mild right hemiparesis and speech disturbance. Other cortical functions were noncontributory. Brain CT scan showed old subcortical infarction of the left frontal lobe and new cerebral infarction. with supramarginal gyrus. The low density area of the supramarginal cortex extended into the subcortical white matter. The language performances in these two cases were similar. Two patients were definitely fluent, but the verbal output was contaminated by paraphasias which were predominantly literal. They performed poorly when attempting to repeat despite good comprehension. Thus, the primary characteristics of conduction aphasia were present. PET studies resulted as follows. 1) rCBF reduced 36 % in the supramarginal cortex, 50 % in the white matter. 2) rCMRO2 reduced 37 % in the supramarginal cortex, 45 % in the white matter. 3) The CBF and the CMRO2 images indicated that cerebral blood flow and oxygen consumption reduced in wider range of area than that shown by brain CT. These results indicated that not only the cortex but also the white matter were damaged in conduction aphasia and several methods including PET should be used to determine the locus of abnormality in conduction aphasia. (author)

  6. Study of conduction aphasia by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, Mikio; Harigawa, Yasuo; Kawarabayashi, Takeshi; Hirai, Shunsaku; Tamada, Junpei.

    1988-04-01

    We reported two cases of conduction aphasia with distinctive language disorder from early stage of stroke, as well as their cerebral blood flow and oxygen consumption investigated with PET. The case was a 72-year-old right handed man whose speech disturbance began acutely. On admission, neurological examination revealed hand pronation sign on the right and speech disturbance. Other neurological findings including cortical functions were normal. Brain CT scan showed low density area in the white matter of the left supramarginal gyrus. The diagnosis was cerebral infarction. The case 2 was a 64-year-old right handed man. He suffered right hemiparesis 2 months before. Neurological examination revealed mild right hemiparesis and speech disturbance. Other cortical functions were noncontributory. Brain CT scan showed old subcortical infarction of the left frontal lobe and new cerebral infarction. with supramarginal gyrus. The low density area of the supramarginal cortex extended into the subcortical white matter. The language performances in these two cases were similar. Two patients were definitely fluent, but the verbal output was contaminated by paraphasias which were predominantly literal. They performed poorly when attempting to repeat despite good comprehension. Thus, the primary characteristics of conduction aphasia were present. PET studies resulted as follows. 1) rCBF reduced 36 % in the supramarginal cortex, 50 % in the white matter. 2) rCMRO/sub 2/ reduced 37 % in the supramarginal cortex, 45 % in the white matter. 3) The CBF and the CMRO/sub 2/ images indicated that cerebral blood flow and oxygen consumption reduced in wider range of area than that shown by brain CT. These results indicated that not only the cortex but also the white matter were damaged in conduction aphasia and several methods including PET should be used to determine the locus of abnormality in conduction aphasia.

  7. Positron Emission Tomography (PET) Studies in Anxiety Disorders

    OpenAIRE

    Michelgård Palmquist, Åsa

    2010-01-01

    Anxiety disorders are very common and the primary feature is abnormal or inappropriate anxiety. Fear and anxiety is often mediated by the amygdala, a brain structure rich in substance P (SP) and neurokinin 1 (NK1) receptors. To learn more about how the human amygdala is modulated by fear and anxiety in event-triggered anxiety disorders and to investigate if the SP/NK1 receptor system is affected, regional cerebral blood flow (rCBF) ([15O]-water; Study I and II) and the SP/NK1 receptor system ...

  8. Persistence of cerebral metabolic abnormalities in chronic schizophrenia as determined by positron emission tomography

    International Nuclear Information System (INIS)

    Local cerebral metabolic rates were determined by positron emission tomography and the deoxyglucose method in a group of 10 chronic schizophrenic subjects before and after somatic treatment and in eight normal subjects. Before treatment, schizophrenic subjects had markedly lower absolute metabolic activity than did normal controls in both frontal and temporal regions and a trend toward relative hyperactivity in the basal ganglia area. After treatment, their metabolic rates approached those seen in normal subjects in nearly all regions except frontal. Persistence of diminished frontal metabolism was manifested as significant relative hypofrontality. These findings suggest specific loci of aberrant cerebral functioning in chronic schizophrenia and the utility of positron emission tomography in characterizing these abnormalities

  9. Scar or recurrent rectal cancer. Positron emission tomography is more helpful for diagnosis than immunoscintigraphy

    International Nuclear Information System (INIS)

    We used positron emission tomography and fludeoxyglucose F-18 to assess metabolic activity of a pelvic mass in 18 patients who had suspected recurrent rectal cancer. Computed tomography could not differentiate tumor from scar. All patients presenting increased uptake of fludeoxyglucose F 18 by the mass were proved by histologic studies to suffer from recurrent tumor. Six of seven patients with low fludeoxyglucose uptake had nonmalignant lesions. Using immunoscintigraphy in 14 patients with elevated carcinoembryonic antigen levels, only four of ten recurrences could be identified by increased antibody accumulation in the mass. On the other hand, two of four benign lesions were interpreted as being recurrent tumor because of high uptake. Therefore, only positron emission tomography seems to be a useful diagnostic tool in the differentiation of recurrent rectal cancer and scar by providing information about the metabolic activity of a mass

  10. [11C]CURB: Evaluation of a novel radiotracer for imaging fatty acid amide hydrolase by positron emission tomography

    International Nuclear Information System (INIS)

    Introduction: Fatty acid amide hydrolase (FAAH) is the enzyme responsible for metabolising the endogenous cannabinoid, anandamide, and thus represents an important target for molecular imaging. To date, no radiotracer has been shown to be useful for imaging of FAAH using either positron emission tomography (PET) or single photon emission computed tomography (SPECT). We here determine the suitability of a novel carbon-11-labeled inhibitor of FAAH via ex vivo biodistribution studies in rat brain in conjunction with pharmacological challenges. Methods: A potent irreversible inhibitor of FAAH, URB694, radiolabeled with carbon-11 in the carbonyl position ([11C]CURB), was administered to male rats via tail-vein injection. Rats were sacrificed at various time points postinjection, and tissue samples were dissected, counted and weighed. Specific binding to FAAH was investigated by pretreatment of animals with URB694 or URB597. For metabolism and mechanism of binding studies, whole brains were excised post-radiotracer injection, homogenised and extracted exhaustively with 80% aq. acetonitrile to determine the time course and fraction of radioactivity that was irreversibly bound to brain parenchyma. Results: Upon intravenous injection into rats, [11C]CURB showed high brain uptake [standard uptake value (SUV) of 1.6-2.4 at 5 min] with little washout over time, which is characteristic of irreversible binding. Highest uptake of radioactivity was seen in the cortex, intermediate in the cerebellum and lowest in the hypothalamus, reflecting the reported distribution of FAAH. Brain uptake of radioactivity was decreased in a dose-dependent manner by pretreatment with increasing amounts of URB694, demonstrating that binding was saturable. Pretreatment with the well-characterised FAAH inhibitor, URB597, reduced binding in all brain regions by 70-80%. Homogenised brain extraction experiments demonstrated unequivocally that [11C]CURB was irreversibly bound to FAAH. Conclusions: The

  11. [{sup 11}C]CURB: Evaluation of a novel radiotracer for imaging fatty acid amide hydrolase by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Alan A., E-mail: alan.wilson@camhpet.c [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Garcia, Armando; Parkes, Jun [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Houle, Sylvain [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Tong, Junchao [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8 (Canada); Vasdev, Neil [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada)

    2011-02-15

    Introduction: Fatty acid amide hydrolase (FAAH) is the enzyme responsible for metabolising the endogenous cannabinoid, anandamide, and thus represents an important target for molecular imaging. To date, no radiotracer has been shown to be useful for imaging of FAAH using either positron emission tomography (PET) or single photon emission computed tomography (SPECT). We here determine the suitability of a novel carbon-11-labeled inhibitor of FAAH via ex vivo biodistribution studies in rat brain in conjunction with pharmacological challenges. Methods: A potent irreversible inhibitor of FAAH, URB694, radiolabeled with carbon-11 in the carbonyl position ([{sup 11}C]CURB), was administered to male rats via tail-vein injection. Rats were sacrificed at various time points postinjection, and tissue samples were dissected, counted and weighed. Specific binding to FAAH was investigated by pretreatment of animals with URB694 or URB597. For metabolism and mechanism of binding studies, whole brains were excised post-radiotracer injection, homogenised and extracted exhaustively with 80% aq. acetonitrile to determine the time course and fraction of radioactivity that was irreversibly bound to brain parenchyma. Results: Upon intravenous injection into rats, [{sup 11}C]CURB showed high brain uptake [standard uptake value (SUV) of 1.6-2.4 at 5 min] with little washout over time, which is characteristic of irreversible binding. Highest uptake of radioactivity was seen in the cortex, intermediate in the cerebellum and lowest in the hypothalamus, reflecting the reported distribution of FAAH. Brain uptake of radioactivity was decreased in a dose-dependent manner by pretreatment with increasing amounts of URB694, demonstrating that binding was saturable. Pretreatment with the well-characterised FAAH inhibitor, URB597, reduced binding in all brain regions by 70-80%. Homogenised brain extraction experiments demonstrated unequivocally that [{sup 11}C]CURB was irreversibly bound to FAAH

  12. An 8×8 Row-Column Summing Readout Electronics for Preclinical Positron Emission Tomography Scanners

    OpenAIRE

    Shih, Y. C.; Sun, F. W.; MacDonald, L R; Otis, B. P.; Miyaoka, R S; McDougald, W.; Lewellen, T K

    2009-01-01

    This work presents a row/column summing readout electronics for an 8×8 silicon photomultiplier array. The summation circuit greatly reduces the number of electronic channels, which is desirable for pursuing higher resolution positron emission tomography scanners. By using a degenerated common source topology in the summation circuit, more fan-in is possible and therefore a greater reduction in the number of electronic channels can be achieved. The timing signal is retrieved from a common anod...

  13. Dynamic Positron Emission Tomography Image Restoration via a Kinetics-Induced Bilateral Filter

    OpenAIRE

    Bian, Zhaoying; Huang, Jing; Ma, Jianhua; Lu, Lijun; Niu, Shanzhou; Zeng, Dong; Feng, Qianjin; Chen, Wufan

    2014-01-01

    Dynamic positron emission tomography (PET) imaging is a powerful tool that provides useful quantitative information on physiological and biochemical processes. However, low signal-to-noise ratio in short dynamic frames makes accurate kinetic parameter estimation from noisy voxel-wise time activity curves (TAC) a challenging task. To address this problem, several spatial filters have been investigated to reduce the noise of each frame with noticeable gains. These filters include the Gaussian f...

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

    Energy Technology Data Exchange (ETDEWEB)

    Schelbert, H.R.; Phelps, M.E.

    1980-06-01

    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.

  15. Value of positron emission tomography in diagnosing synchronous penile metastasis from urothelial bladder cancer

    OpenAIRE

    Rouanne, M.; Alhammadi, A.; Vilain, D.; Radulescu, C.; Lebret, T.

    2015-01-01

    Metastases to the penis are extremely rare events. Most frequently, penile metastases come from the urogenital system (bladder, prostate) or the rectum-sigmoid colon. Usually painful, penile lesions may be asymptomatic, making diagnosis more challenging. Hence, we report the adding value of 18F-fludeoxyglucose–positron emission tomography/computed tomography (18F-FDG PET/CT) in the detection of penile metastases originating from urothelial carcinoma of the bladder. Arguably, penile metastases...

  16. Positron emission tomography radioligands for in vivo imaging of Aβ plaques

    OpenAIRE

    Mason, N Scott; Mathis, Chester A.; Klunk, William E

    2013-01-01

    The development of positron emission tomography (PET) radioligands for the non-invasive imaging of amyloid-β plaque burden has been the focus of intense research efforts over the last decade. A variety of structural backbones have been investigated and several radiolabeled molecules have been evaluated in phase I (and later) clinical studies. These efforts have been driven by the desire not only to develop a suitable diagnostic imaging agent but also to develop a means to evaluate potential t...

  17. [(18)F]Fluoroethyltyrosine- positron emission tomography-guided radiotherapy for high-grade glioma

    OpenAIRE

    Ratib Osman; Dipasquale Giovanna; Nouet Philippe; Rouzaud Michel; Haller Guy; Casanova Nathalie; Buchegger Franz; Zilli Thomas; Weber Damien C; Zaidi Habib; Vees Hansjorg; Miralbell Raymond

    2008-01-01

    Abstract Background To compare morphological gross tumor volumes (GTVs), defined as pre- and postoperative gadolinium enhancement on T1-weighted magnetic resonance imaging to biological tumor volumes (BTVs), defined by the uptake of 18F fluoroethyltyrosine (FET) for the radiotherapy planning of high-grade glioma, using a dedicated positron emission tomography (PET)-CT scanner equipped with three triangulation lasers for patient positioning. Methods Nineteen patients with malignant glioma were...

  18. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Rydhög, J. S.; Søndergaard, Rikke Vicki;

    2016-01-01

    Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver......, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy...

  19. Positron emission tomography in cases of chorea with different underlying diseases.

    OpenAIRE

    Hosokawa, S.; Ichiya, Y; Kuwabara, Y; Ayabe, Z; Mitsuo, K; Goto, I; Kato, M.

    1987-01-01

    Local cerebral metabolic rate for glucose (LCMRglc) was measured with positron emission tomography using the 18F-fluorodeoxy-glucose method in five patients with chorea due to different underlying diseases. Hypometabolism was observed in the striatum bilaterally in patients with Huntington's disease, choreoacanthocytosis, sporadic progressive chorea and dementia, and pseudo-Huntington form of dentato-rubro-pallido-luysian atrophy (DRPLA). The patient with hemichorea showed hypometabolism in t...

  20. Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography

    International Nuclear Information System (INIS)

    While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography (13N-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

  1. Photo-Detectors for Time of Flight Positron Emission Tomography (ToF-PET)

    OpenAIRE

    Levin, Craig S; Virginia Ch. Spanoudaki

    2010-01-01

    We present the most recent advances in photo-detector design employed in time of flight positron emission tomography (ToF-PET). PET is a molecular imaging modality that collects pairs of coincident (temporally correlated) annihilation photons emitted from the patient body. The annihilation photon detector typically comprises a scintillation crystal coupled to a fast photo-detector. ToF information provides better localization of the annihilation event along the line formed by each detector pa...

  2. The establishment of crystal position look-up table for positron emission tomography with block detectors

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors. It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model (GMM). This method has taken full consideration of the characteristics of the GMM and the detector itself. The experimental results have proved that it is simple, reliable, and universal.

  3. Positron emission tomography-computed tomography has a clinical impact for patients with cervical cancer

    DEFF Research Database (Denmark)

    Sandvik, Rikke Mulvad; Jensen, Pernille Tine; Hendel, Helle W;

    2011-01-01

    Many studies have found that positron emission tomography-computed tomography (PET-CT) has a high sensitivity and specificity in the identification of metastasis in cervical cancer. Herlev Hospital, Denmark, has been performing PET-CTs in stage I-IV cervical cancer since 1 May 2006. The present...... study investigates the positive (PPV) and negative predictive value (NPV) of PET-CT in stage I disease and the clinical impact of the scan results in all disease stages....

  4. Regional structure-function correlations in chronic obstructive lung disease measured with positron emission tomography.

    OpenAIRE

    Brudin, L H; Rhodes, C G; Valind, S O; Buckingham, P D; Jones, T; Hughes, J. M.

    1992-01-01

    BACKGROUND: Positron emission tomography, performed with isotopes of very short half life, can be used to relate local lung tissue density to local ventilation and to the ventilation:perfusion ratio. This method has been used in 10 patients with severe chronic airflow obstruction and differing values for carbon monoxide transfer factor (TLCO) and transfer coefficient (KCO). METHODS: Ventilation (VA) and the ventilation:perfusion ratio (V/Q), lung density, and blood volume were measured region...

  5. Usefulness of myocardial positron emission tomography/nuclear imaging in Takotsubo cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    Marzia; Testa; Mauro; Feola

    2014-01-01

    AIM:To analyse and summarize all the articles related to positron emission tomography and Takotsubo cardiomyopathy(TTC).METHODS:We performed a systematic review of the existing literature on positron emission tomography/nuclear imaging and Takotsubo cardiomyopathy using PUBMED database.We combined search terms such as"takotsubo","takotsubo syndrome","myocardial positron emission tomography","positron emission tomography".All case reports were excluded.The list included only four articles which were reviewed by two independent investigators.It was not possible to undertake a formal meta-analysis because of the heterogeneity of the studies;therefore,we made a narrative synthesis of the collected data.RESULTS:Nuclear medicine techniques can be useful employed in the differential diagnosis of TTC from an acute coronary syndrome(ACS).In fact,transient left ventricular(LV)apical ballooning is a syndrome frequently misdiagnosed as an ACS and can mimic symptoms of myocardial infarction with ST-T segments changes on electrocardiography(ECG),a limited re-lease of myocardial enzyme,mainly reported after sudden emotional or physical stress,and an akinesis or dyskinesis of the left ventricle apex which are completely reversible in a few weeks.In the studies included in this review,nuclear medicine techniques have demonstrated a discrepancy between normal perfusion and a reduced glucose utilization in TTC,commonly known as"inverse flow metabolism mismatch".This suggests that apical ballooning represents a transient metabolic disorder on the cellular level,rather than a structural contractile disease of the myocardium,due to a transient decrease of glucose metabolism that might be related to a coronary microcirculation impairment followed by prolonged myocardial stunning.CONCLUSION:Nuclear medicine techniques can be usefully used for the diagnosis of TTC and can increase our knowledge of the pathophysiological mechanisms of TTC.

  6. Exogenous lipoid pneumonia with unusual CT pattern and FDG positron emission tomography scan findings

    International Nuclear Information System (INIS)

    We report a case of an exogenous lipoid pneumonia that appeared as a spiculated calcified mass on CT scan in which a positron emission tomography (PET) scan was performed before histological analysis. The F-18 fluoro-deoxy-D-glucose (FDG) PET showed a pattern highly suggestive of malignancy which, to our knowledge, has not yet been described. Similar to inflammatory and infectious lung diseases, lipoid pneumonia may be a false-positive case of F-18 FDG uptake. (orig.)

  7. Exogenous lipoid pneumonia with unusual CT pattern and FDG positron emission tomography scan findings

    Energy Technology Data Exchange (ETDEWEB)

    Tahon, Florence; Berthezene, Yves; Blineau, Nadine; Marchand, Bruno [Department of Radiology, Hopital de la Croix-Rousse, 103 grande rue de la Croix-Rousse, 69317 Lyon Cedex (France); Hominal, Stephane; Guerin, Jean-Claude [Department of Chest, Hopital de la Croix-Rousse, 103 grande rue de la Croix-Rousse, 69317 Lyon Cedex (France); Cinotti, Luc [CERMEP, 59 bd Pinel, 69003 Lyon Cedex (France)

    2002-07-01

    We report a case of an exogenous lipoid pneumonia that appeared as a spiculated calcified mass on CT scan in which a positron emission tomography (PET) scan was performed before histological analysis. The F-18 fluoro-deoxy-D-glucose (FDG) PET showed a pattern highly suggestive of malignancy which, to our knowledge, has not yet been described. Similar to inflammatory and infectious lung diseases, lipoid pneumonia may be a false-positive case of F-18 FDG uptake. (orig.)

  8. Imaging Chronic Pain and Inflammation : Positron Emission Tomography Studies of Whiplash Associated Disorder

    OpenAIRE

    Linnman, Clas

    2008-01-01

    This thesis is on chronic neck pain after a rear impact car injury, so called whiplash associated disorder (WAD). Three empirical studies using positron emission tomography (PET) with different radioligands have been performed. The first study evaluated resting state regional cerebral blood flow (rCBF) in WAD patients and in healthy, pain-free controls, by use of oxygen-15 labeled water. Patients had heightened resting rCBF bilaterally in the posterior parahippocampal and the posterior cingul...

  9. Identifying active vascular micro-calcification by 18F-sodium fluoride positron emission tomography

    OpenAIRE

    Irkle, Agnese; Vesey, Alex T.; Lewis, David Y.; Jeremy N Skepper; Bird, Joseph L. E.; Dweck, Marc R; Joshi, Francis R.; Gallagher, Ferdia A.; Warburton, Elizabeth A; Bennett, Martin R; Kevin M. Brindle; Newby, David E; Rudd, James H.; Davenport, Anthony P.

    2015-01-01

    Vascular calcification is a complex biological process that is a hallmark of atherosclerosis. While macrocalcification confers plaque stability, microcalcification is a key feature of high-risk atheroma and is associated with increased morbidity and mortality. Positron emission tomography and X-ray computed tomography (PET/CT) imaging of atherosclerosis using 18F-sodium fluoride (18F-NaF) has the potential to identify pathologically high-risk nascent microcalcification. However, the precise m...

  10. Identifying active vascular microcalcification by (18)F-sodium fluoride positron emission tomography

    OpenAIRE

    Irkle, Agnese; Vesey, Alex T.; Lewis, David Y.; Jeremy N Skepper; Bird, Joseph L. E.; Dweck, Marc R; Joshi, Francis R.; Gallagher, Ferdia A.; Warburton, Elizabeth A; Bennett, Martin R; Kevin M. Brindle; Newby, David E; Rudd, James H.; Davenport, Anthony P.

    2015-01-01

    Vascular calcification is a complex biological process that is a hallmark of atherosclerosis. While macrocalcification confers plaque stability, microcalcification is a key feature of high-risk atheroma and is associated with increased morbidity and mortality. Positron emission tomography and X-ray computed tomography (PET/CT) imaging of atherosclerosis using (18)F-sodium fluoride ((18)F-NaF) has the potential to identify pathologically high-risk nascent microcalcification. However, the preci...

  11. Clinical Imaging Characteristics of the Positron Emission Mammography Camera: PEM Flex Solo II

    OpenAIRE

    MacDonald, Lawrence; Edwards, John; Lewellen, Thomas; Haseley, David; Rogers, James; Kinahan, Paul

    2009-01-01

    We evaluated a commercial positron emission mammography (PEM) camera, the PEM Flex Solo II. This system comprises two 6 × 16.4 cm detectors that scan together covering up to a 24 × 16.4 cm field of view (FOV). There are no specific standards for testing this detector configuration. We performed several tests important to breast imaging, and we propose tests that should be included in standardized testing of PEM systems.

  12. Fluorodeoxyglucose positron emission tomography-computed tomography findings in a case of xanthogranulomatous pyelonephritis

    OpenAIRE

    Joshi, Prathamesh; Lele, Vikram; Shah, Hardik

    2013-01-01

    Xanthogranulomatous pyelonephritis (XGNP) is an uncommon condition characterized by chronic suppurative renal inflammation that leads to progressive parenchymal destruction. This condition can clinically present as recurrent urinary tract infections, flank pain, hematuria, and occasionally sepsis, and weight loss. This condition is usually associated with obstructing renal calculus. We present 18-fluorodeoxyglucose positron emission tomography-computed tomography (18-FDG PET/CT) findings in a...

  13. Optimization of In-Beam Positron Emission Tomography for Monitoring Heavy Ion Tumor Therapy

    OpenAIRE

    Vieira Crespo, Paulo Alexandre

    2010-01-01

    In-beam positron emission tomography (in-beam PET) is currently the only method for an in-situ monitoring of highly tumor-conformed charged hadron therapy. In such therapy, the clinical effect of deviations from treatment planning is highly minimized by implementing safety margins around the tumor and selecting proper beam portals. Nevertheless, in-beam PET is able to detect eventual, undesirable range deviations and anatomical modifications during fractionated irradiation, to verify the accu...

  14. Transcutaneous measurement of the arterial input function in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) provides a powerful tool in medical research. Biochemical function can be both precisely localized and quantitatively measured. To achieve reliable quantitation it is necessary to know the time course of activity concentration in the arterial blood during the measurement. In this study the arterial blood curve from the brachial artery is compared to the activity measured in the internal carotid artery with a new transcutaneous detector

  15. Human hemispheric infarction studied by positron emission tomography and the 15O continuous inhalation technique

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) offers an entirely new approach to the study of the pathophysiology of cerebral ischemic disorders. For the first time it is possible to obtain functional tomographic images that represent cerebral perfusion and metabolism on a regional basis. We report here a study of cerebral blood flow and oxygen extraction by means of the 15O inhalation technique in a large number of human hemispheric infarctions. (orig.)

  16. Synthesis of Novel Neutrophil-Specific Imaging Agents for Positron Emission Tomography (PET) Imaging

    OpenAIRE

    ZHANG Yi; Kundu, Bijoy; Fairchild, Karen D.; Locke, Landon; Berr, Stuart S.; Linden, Joel; Pan, Dongfeng

    2007-01-01

    A neutrophil specific peptide, cinnamoyl-F(D)LF(D)LFK (cFLFLFK), was conjugated consecutively with a polyethylene glycol moiety (3.4 K) and 2,2′,2″,2‴-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) to form cFLFLFK-PEG-DOTA. After 64Cu labeling, Positron Emission Tomography (PET) imaging was successfully able to detect mouse lung inflammation.

  17. Dynamic positron emission tomography in man using small bismuth germanate crystals

    International Nuclear Information System (INIS)

    Primary considerations for the design of positron emission tomographs for medical studies in humans are the need for high imaging sensitivity, whole organ coverage, good spatial resolution, high maximum data rates, adequate spatial sampling with minimum mechanical motion, shielding against out of plane activity, pulse height discrimination against scattered photons, and timing discrimination against accidental coincidences. We discuss the choice of detectors, sampling motion, shielding, and electronics to meet these objectives

  18. Combined use of positron emission tomography and volume doubling time in lung cancer screening with low-dose CT scanning

    DEFF Research Database (Denmark)

    Ashraf, H; Dirksen, A; Jakobsen, Annika Loft;

    2011-01-01

    In lung cancer screening the ability to distinguish malignant from benign nodules is a key issue. This study evaluates the ability of positron emission tomography (PET) and volume doubling time (VDT) to discriminate between benign and malignant nodules....

  19. The Marinesco-Sjoegren syndrome examined by computed tomography, magnetic resonance, and 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography

    International Nuclear Information System (INIS)

    The Marinesco-Sjoegren syndrome is an autosomal recessive degenerative disorder characterized by congenital cataracts, cerebellar ataxia, spasticity, mental deficiency, and skeletal abnormalities. We studied two adult siblings with Marinesco-Sjoegren syndrome using anatomic and metabolic brain imaging techniques to characterize the pattern and nature of abnormalities in the brain. Computed tomographic and magnetic resonance imaging showed diffuse brain atrophy of mild to moderate degree, involving primarily the white matter of the cerebrum, cerebellum, brain stem, and cervical spinal cord. The pattern of atrophy resembled that seen in diffuse leukoencephalopathies. Measurements of local cerebral glucose metabolic rates with positron emission tomography revealed no statistically significant differences from normal control subjects in most regions, but metabolic rate was decreased in the thalamus in one patient. The findings support a diffuse white matter disorder in Marinesco-Sjoegren syndrome.Aut

  20. Assessment of regional myocardial and renal blood flow with copper-PTSM and positron emission tomography.

    Science.gov (United States)

    Shelton, M E; Green, M A; Mathias, C J; Welch, M J; Bergmann, S R

    1990-09-01

    We recently demonstrated in isolated, perfused hearts that radiolabeled pyruvaldehyde bis(N4-methylthiosemicarbazonato)copper(II) (Cu-PTSM) is well extracted throughout a range of conditions including ischemia, hypoxia, and hyperemia. Once extracted, binding of radioactivity by the isolated heart was essentially irreversible, giving this tracer microspherelike qualities. Because Cu-PTSM can be readily prepared with the generator-produced positron-emitting copper 62 and other gamma- or positron-emitting copper radionuclides, we evaluated its usefulness for measuring regional myocardial and renal blood flow in vivo in intact dogs at rest, after ischemia, or after coronary hyperemia was induced by intravenous administration of dipyridamole. After intravenous administration of radiolabeled Cu-PTSM, the tracer cleared rapidly from the blood. Myocardial uptake of single photon-emitting 67Cu-labeled Cu-PTSM was measured directly in myocardial samples 15 minutes after tracer administration, and it increased proportionally with blood flow throughout the flow range (estimated concomitantly with radiolabeled microspheres) of 0.0-6.0 ml/g/min (n = 340 samples from 17 dogs, r = 0.99, Ycopper radioactivity = 85Xmicrosphere flow -7 chi 2 + 17). Renal uptake of radiolabeled Cu-PTSM was also proportional to blood flow. Positron emission tomography was performed in four intact dogs after intravenous administration of 64Cu-labeled Cu-PTSM (19% positron decay, t1/2 = 12.8 hours). High-quality images of heart and kidney were obtained. Accordingly, radiolabeled Cu-PTSM should be a useful, generator-produced tracer for estimating regional myocardial and renal blood flow with positron emission tomography. PMID:2394015

  1. Drug distribution in man: a positron emission tomography study after oral administration of the labelled neuroprotective drug vinpocetine

    International Nuclear Information System (INIS)

    Direct information on the distribution of a drug requires measurements in various tissues. Such data have until now been obtained in animals, or have indirectly been calculated from plasma measurements in humans using mathematical models. Here we suggest the use of positron emission tomography (PET) as a method to obtain direct measurements of drug distribution in the human body. The distribution in body and brain of vinpocetine, a neuroprotective drug widely used in the prevention and treatment of cerebrovascular diseases, was followed after oral administration. Vinpocetine was labelled with carbon-11 and radioactivity was measured by PET in stomach, liver, brain and kidney in six healthy volunteers. The radioactivity in blood and urine as well as the fractions of [11C]vinpocetine and labelled metabolites in plasma were also determined. After oral administration, [11C]vinpocetine appeared immediately in the stomach and within minutes in the liver and the blood. In the blood the level of radioactivity continuously increased until the end of the measurement period, whereas the fraction of the unchanged mother compound decreased. Radioactivity uptake and distribution in the brain were demonstrable from the tenth minute after the administration of the labelled drug. Brain distribution was heterogeneous, similar to the distribution previously reported after intravenous administration. These findings indicate that vinpocetine, administered orally in humans, readily enters the bloodstream from the stomach and gastrointestinal tract and, consequently, passes the blood-brain barrier and enters the brain. Radioactivity from [11C]vinpocetine was also demonstrated in the kidneys and in urine, indicating that at least a part of the radioactive drug and labelled metabolites is eliminated from the body through the kidneys. This study is the first to demonstrate that PET might be a useful, direct and non-invasive tool to study the distribution and pharmacokinetics of orally

  2. Tomography by positrons emission: integral unit to the service of Mexico; Tomografia por emision de positrones: unidad integral al servicio de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez D, F.A. [Unidad PET-Ciclotron, Facultad de Medicina, UNAM (Mexico)]. e-mail: fred-alonso@correo.unam.mx

    2005-07-01

    The applications of the Positron emission tomography (PET) together with the one radiopharmaceutical 2 - [{sup 18} F]-fluoro-2-deoxy-D-glucose in the area of the medical imaging is expanding quickly and it possesses a bigger impact at the moment in favor of those patient to who suffers an oncological, cardiac or neurological illness in Mexico. (Author)

  3. A positron emission tomography study of nigro-striatal dopaminergic mechanisms underlying attention: implications for ADHD and its treatment

    OpenAIRE

    del Campo, Natalia; Fryer, Tim D; Hong, Young T.; Smith, Rob; Brichard, Laurent; Acosta-Cabronero, Julio; Chamberlain, Samuel R.; Tait, Roger; Izquierdo, David; Regenthal, Ralf; Dowson, Jonathan; Suckling, John; Baron, Jean-Claude; Aigbirhio, Franklin I.; Robbins, Trevor W.

    2013-01-01

    Through the combined use of 18F-fallypride positron emission tomography and magnetic resonance imaging this study examined the neural mechanisms underlying the attentional deficits associated with attention deficit/hyperactivity disorder and their potential reversal with a single therapeutic dose of methylphenidate. Sixteen adult patients with attention deficit/hyperactivity disorder and 16 matched healthy control subjects were positron emission tomography and magnetic resonance imaging scann...

  4. Synthesis and positron emission tomography studies of carbon-11-labeled imatinib (Gleevec)

    Energy Technology Data Exchange (ETDEWEB)

    Kil, Kun-Eek [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400 (United States); Ding Yushin [Department of Radiology, Yale University School of Medicine, New Haven, CT 06520-8048 (United States); Lin Kuoshyan [Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Alexoff, David [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Kim, Sung Won [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400 (United States); Shea, Colleen [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Xu Youwen [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Muench, Lisa [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Fowler, Joanna S. [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States) and Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400 (United States)]. E-mail: fowler@bnl.gov

    2007-02-15

    Introduction: Imatinib mesylate (Gleevec) is a well known drug for treating chronic myeloid leukemia and gastrointestinal stromal tumors. Its active ingredient, imatinib ([4-[(4-methyl-1-piperazinyl)methyl]-N-[4-methyl-3-[[4-(3-pyridyl) -2-pyrimidinyl]amino]phenyl]benzamide), blocks the activity of several tyrosine kinases. Here we labeled imatinib with carbon-11 as a tool for determining the drug distribution and pharmacokinetics of imatinib, and we carried out positron emission tomography (PET) studies in baboons. Methods: [N-{sup 11}C-methyl]imatinib was synthesized from [{sup 11}C]methyl iodide and norimatinib was synthesized by the demethylation of imatinib (isolated from Gleevec tablets) according to a patent procedure [Collins JM, Klecker RW Jr, Anderson LW. Imaging of drug accumulation as a guide to antitumor therapy. US Patent 20030198594A1, 2003]. Norimatinib was also synthesized from the corresponding amine and acid. PET studies were carried out in three baboons to measure pharmacokinetics in the brain and peripheral organs and to determine the effect of a therapeutic dose of imatinib. Log D and plasma protein binding were also measured. Results: [N-{sup 11}C-methyl]imatinib uptake in the brain is negligible (consistent with P-glycoprotein-mediated efflux); it peaks and clears rapidly from the heart, lungs and spleen. Peak uptake and clearance occur more slowly in the liver and kidneys, followed by accumulation in the gallbladder and urinary bladder. Pretreatment with imatinib did not change uptake in the heart, lungs, kidneys and spleen, and increased uptake in the liver and gallbladder. Conclusions: [N-{sup 11}C-methyl]imatinib has potential for assessing the regional distribution and kinetics of imatinib in the human body to determine whether the drug targets tumors and to identify other organs to which the drug or its labeled metabolites distribute. Paired with tracers such as 2'deoxy-2'-[{sup 18}F]fluoro-D-glucose ({sup 18}FDG) and 3&apos

  5. Depressed cerebral oxygen metabolism in patients with chronic renal failure. A positron emission tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Hirakata, Hideki; Kanai, Hidetoshi; Nakane, Hiroshi; Fujii, Ken-ichiro; Hirakata, Eriko; Ibayashi, Setsuro; Kuwabara, Yasuo; Deenitchna, S.S.; Fujishima, Masatoshi [Kyushu Univ., Fukuoka (Japan). Graduate School of Medical Sciences

    2001-07-01

    In order to elucidate brain oxygen metabolism in uremic patients, the regional cerebral blood flow (rCBF), oxygen extraction (rOEF) and oxygen metabolism (rCMRO{sub 2}) were measured by positron emission tomography (PET) in both 10 hemodialysis patients (HD: male [m]/female [f]=2/8, age of 49{+-}3 [SEM] years old, HD duration of 113{+-}26 months) and 13 pre-dialysis renal failure patients (CRF: m/f=10/3, age of 61{+-}2 years old, serum creatinine (SCr) of 6.3{+-}1.0 mg/dl). Data were compared with 20 non-uremic subjects (Control: m/f=7/13, age of 62{+-}2 years old, SCr of 0.9{+-}0.1 mg/dl). They had no neurological abnormalities, congestive heart failure, history of cerebrovascular accident, diabetes mellitus, or symptomatic brain lesion on magnetic resonance imaging. The age of HD was significantly younger than the other groups (p<0.02) and the hemoglobin (Hb) levels in both HD (10.5{+-}0.5 g/dl) and CRF (9.8{+-}0.9) were significantly lower than that in Control (13.3{+-}0.3) (p<0.02). In the hemisphere, rCMRO{sub 2} in both HD (1.82{+-}0.10 ml/min/100 g) and CRF (1.95{+-}0.09) showed significantly lower values as compared to Control (2.23{+-}0.05) (p<0.01, respectively). Hemispheric rCBF in HD (35.6{+-}2.1 ml/100 g/min) and in CRF (36.1{+-}2.1) were not different from that in Control (31.8{+-}1.4). Hemispheric rOEF in CRF (45.7{+-}1.6%) was significantly higher than that in Control (40.5{+-}1.2%) (p<0.02), but that in HD (43.7{+-}1.9%) did not increase significantly. These tendencies were similar in all regions of interest, especially in the cerebral cortices, but not in the cerebellum. All PET parameters in the frontal cortices tended to show the lowest value in renal failure patients. For all HD patients, rCBF in both the frontal cortex and the white matter correlated inversely with HD duration (frontal cortex: r=-0.649, p<0.05; white matter: r=-0.706, p<0.02). Based on these data, it is concluded that brain oxygen metabolism is depressed in renal failure

  6. [18F]-Fluoro-Deoxy-Glucose Positron Emission Tomography Scan Should Be Obtained Early in Cases of Autoimmune Encephalitis

    Science.gov (United States)

    Sarwal, A.; Hantus, S.

    2016-01-01

    Introduction. Autoimmune encephalitis (AE) is a clinically challenging diagnosis with nonspecific neurological symptoms. Prompt diagnosis is important and often relies on neuroimaging. We present a case series of AE highlighting the importance of an early [18F]-fluoro-deoxy-glucose positron emission tomography (FDG-PET) scan. Methods. Retrospective review of seven consecutive cases of autoimmune encephalitis. Results. All patients had both magnetic resonance imaging (MRI) and FDG-PET scans. Initial clinical presentations included altered mental status and/or new onset seizures. Six cases had serum voltage-gated potassium channel (VGKC) antibody and one had serum N-methyl-D-aspartate (NMDA) antibody. MRI of brain showed mesial temporal lobe hyperintensity in five cases of VGKC. The other two patients with VGKC or NMDA AE had restiform body hyperintensity on MRI brain or a normal MRI, respectively. Mesial temporal lobe hypermetabolism was noted in three cases on FDG-PET, despite initial unremarkable MRI. Malignancy workup was negative in all patients. Conclusion. A high index of suspicion for AE should be maintained in patients presenting with cognitive symptoms, seizures, and limbic changes on neuroimaging. In cases with normal initial brain MRI, FDG-PET can be positive. Additionally, extralimbic hyperintensity on MRI may also be observed.

  7. Positron emission tomography in presurgical evaluation of epilepsy

    International Nuclear Information System (INIS)

    In a considerable proportion of patients with medically intractable partial epilepsies who are considered for surgery, the detection of a lesion with MRI or CT is not possible. Functional imaging methods can provide clinically useful information in these cases, being methods which enable localisation of functional abnormalities independent from EEG. There is an extensive knowledge about interictal PET-investigations with F-18 FDG. Many centers dealing with preoperative evaluation of epilepsy use this method as part of their diagnostic routine. Most studies report a decrease of glucose metabolism in topographic correlation to the EEG defined seizure origin in temporal lobe epilepsy in 70%-85% of the patients. The sensitivity reported for the detection of extratemporal foci is markedly lower. The mapping of neuronal structures with specific ligands, i.e. benzodiazepine receptor ligands has advantages compared to the detection of changes in flow and metabolism. It enables the differentiation of abnormalities in the neuronal texture of the brain from deactivated cortical areas. This is especially important when surgical procedures other than standard resection techniques are considered. The clinical importance of the functional imaging methods is that they help to decrease the amount of invasive EEG recordings in temporal lobe epilepsy. Furthermore, in extratemporal epilepsies functional imaging techniques facilitate the placement of the electrodes for invasive EEG recording. (orig.)

  8. High-resolution PET [Positron Emission Tomography] for Medical Science Studies

    Science.gov (United States)

    Budinger, T. F.; Derenzo, S. E.; Huesman, R. H.; Jagust, W. J.; Valk, P. E.

    1989-09-01

    One of the unexpected fruits of basic physics research and the computer revolution is the noninvasive imaging power available to today's physician. Technologies that were strictly the province of research scientists only a decade or two ago now serve as the foundations for such standard diagnostic tools as x-ray computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), ultrasound, single photon emission computed tomography (SPECT), and positron emission tomography (PET). Furthermore, prompted by the needs of both the practicing physician and the clinical researcher, efforts to improve these technologies continue. This booklet endeavors to describe the advantages of achieving high resolution in PET imaging.

  9. Patient radiation protection in positron emission tomography; Proteccion radiologica del paciente en la tomografia por emision de positrones

    Energy Technology Data Exchange (ETDEWEB)

    Marti-Climent, J. M.; Garcia-Velloso, M. J. [Universidad de Navarra. (Spain)

    2003-07-01

    Patient radiation protection in Positron Emission Tomography (PET) is closely related to the correct execution of studies: proper scanner performance, and optimization of both image quality and patient dose. We describe the quality control tests considered as essential: scanner stability, spatial resolution, sensitivity and tomographic uniformity. Knowledge of the dose received by the critical organ and the effective dose for each radiopharmaceutical allows the establishment of strategies for dose optimization. Although a great variety of PET tracers exist, we review the dose produced by F-FDG, the most widely used tracer, and those used in our PET Center O-Water, N-Ammonia, C-Methionine, C-Choline, F-Choline, F-Dopa, and F-FHBG. Reduction of administered activity to the patient is the direct way to reduce the dose. Thus, PET acquisition in the 3D mode, with higher sensitivity, is a determining factor. In order to reduce the dose to different organs, efforts should be directed to the critical organs, mainly the urinary bladder wall. Finally, correct patient preparation improves, PET image quality, due to an optimum tracer uptake, which optimizes the dose to different organs. (Author) 25 refs.

  10. {sup 64} Cu-pyruvaldehide-bis-(N{sup 4} methyl-thio semi-carbazone) - Cu-PTSM as brain tracer for positron emission tomography; Cu-piruvaldehido-bis-(N{sup 4} metiltiosemicarbazona) o Cu-PSTM como trazador cerebral para tomografia por emision de positrones

    Energy Technology Data Exchange (ETDEWEB)

    Arguelles, M.G.; Lago Fernandez, J.L.; Casale, G.A.; Torres, E.A. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina)

    1995-12-31

    Synthesis of Pyruvaldehide-bis-(N{sup 4}-methyl-thio semicarbazone) PTSM used for medical investigation and diagnosis has been carried out in our Radiopharmaceutical Division in Centro Atomico Ezeiza. PTSM has been obtained introducing modifications to a previous synthesis published by H.G. Petering TLC, HPLC and IR, UV spectrum controls have been performed. Cu-64 can be obtained by the Cu-63 (n, {gamma}) and Zn-64 (n,p) reactions. This last reaction has been chosen for the production in the RA-3 reactor since it leads to Cu-64 of high specific activity. Two different assays have been performed to obtain the chelate PTSM-Cu-64. The first one has beer carried out by buffering the Cu-64 solution to pH 3-4; adding the PTSM solution in ethanol. The second assay has been carried out by buffering the Cu-64 solution with sodium acetate 3 M and adding 100 {mu}l of PTSM solution in ethanol. The chelate thus obtained is purified in Sepak C-18. Radiochemical purity has been tested by thin layer chromatography. Biodistribution studies have been carried on NIH mice and Wistar rats showing a brain uptake of 4%, 30 minutes after injection. Thus, FTMS-Cu-64 proves to be a good brain diagnosis agent. (author). 7 refs., 3 figs.

  11. Geneva University - The AX-PET experiment : A demonstrator for an axial Positron Emission Tomography

    CERN Multimedia

    Université de Genève

    2012-01-01

    Geneva University École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92   Wednesday 14 March 2012 SEMINAIRE DE PHYSIQUE CORPUSCULAIRE 11.15 a.m. - Science II, Auditoire 1S081, 30, quai Ernest-Ansermet, 1211 Genève 4 The AX-PET experiment : A demonstrator for an axial Positron Emission Tomography Dr Chiara CASELLA   ETH Zurich   PET (Positron Emission Tomography) is a tool for in-vivo functional imaging, successfully used since the earliest days of nuclear medicine. It is based on the detection of the two coincident 511 keV photons from the annihilation of a positron, emitted from a radiotracer injected into the body. Tomographic analysis of the coincidence data allows for a 3D reconstructed image of the source distribution. The AX-PET experiment proposes a novel geometrical approach for a PET scanner, in which l...

  12. High power laser production of short-lived isotopes for positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) is a powerful diagnostic/imaging technique requiring the production of the short-lived positron emitting isotopes 11C, 13N, 15O and 18F by proton irradiation of natural/enriched targets using cyclotrons. The development of PET has been hampered due to the size and shielding requirements of nuclear installations. Recent results show that when an intense laser beam interacts with solid targets, megaelectronvolt (MeV) protons capable of producing PET isotopes are generated. This report describes how to generate intense PET sources of 11C and 18F using a petawatt laser beam. The work describing the laser production of 18F through a (p,n) 18O reaction, and the subsequent synthesis of 2-[18F] is reported for the first time. The potential for developing compact laser technology for this purpose is discussed

  13. The 511 keV emission from positron annihilation in the Galaxy

    CERN Document Server

    Prantzos, N; Bykov, A M; Diehl, R; Ferriere, K; Guessoum, N; Jean, P; Knoedlseder, J; Marcowith, A; Moskalenko, I V; Strong, A; Weidenspointner, G

    2010-01-01

    The first gamma-ray line originating from outside the solar system that was ever detected is the 511 keV emission from positron annihilation in the Galaxy. Despite 30 years of intense theoretical and observational investigation, the main sources of positrons have not been identified up to now. Observations in the 1990's with OSSE/CGRO showed that the emission is strongly concentrated towards the Galactic bulge. In the 2000's, the SPI instrument aboard ESA's INTEGRAL gamma-ray observatory allowed scientists to measure that emission across the entire Galaxy, revealing that the bulge/disk luminosity ratio is larger than observed in any other wavelength. This mapping prompted a number of novel explanations, including rather "exotic ones (e.g. dark matter annihilation). However, conventional astrophysical sources, like type Ia supernovae, microquasars or X-ray binaries, are still plausible candidates for a large fraction of the observed total 511 keV emission of the bulge. A closer study of the subject reveals new...

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

    International Nuclear Information System (INIS)

    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

  15. Chronic morphine upregulates a μ-opiate binding site labeled by [3H]cycloFOXY: a novel opiate antagonist suitable for positron emission tomography

    International Nuclear Information System (INIS)

    CycloFOXY (17-cyclopropylmethyl-3,14-dihydroxy-4,5-α-epoxy-6-β-fluoromorphinan) is a novel opiate antagonist synthesized as a ligand suitable for in vivo visualization of opiate receptors using positron emission transaxial tomography. In this paper it is reported that [3H]cycloFOXY labels two distinct opiate binding sites in rat brain membranes, tentatively identified as μ and κ. Furthermore, chronic administration of morphine results in a selective up-regulation of the μ binding site. The implications of this finding for models of the opioid receptors and the mechanism of the sodium effect are discussed. 34 refs.; 1 figure; 4 tabs

  16. Metabolism and quantification of [18F]DPA-714, a new TSPO positron emission tomography radioligand

    International Nuclear Information System (INIS)

    [18F]DPA-714 [N,N-diethyl-2-(2-(4-(2[18F]-fluoroethoxy)phenyl) 5,7-dimethyl-pyrazolo[1,5a]pyrimidin-3-yl)acetamide] is a new radioligand currently used for imaging the 18-kDa translocator protein in animal models of neuro-inflammation and recently in humans. The biodistribution by positron emission tomography (PET) in baboons and the in vitro and in vivo metabolism of [18F]DPA-714 were investigated in rats, baboons, and humans. Whole-body PET experiments showed a high uptake of radioactivity in the kidneys, heart, liver, and gallbladder. The liver was a major route of elimination of [18F]DPA-714, and urine was a route of excretion for radio-metabolites. In rat and baboon plasma, high-performance liquid chromatography (HPLC) metabolic profiles showed three major radio-metabolites accounting for 85% and 89% of total radioactivity at 120 minutes after injection, respectively. Rat microsomal incubations and analyses by liquid chromatography-mass spectrometry (LC-MS) identified seven metabolites, characterized as O-de-ethyl, hydroxyl, and N-de-ethyl derivatives of nonradioactive DPA-714, two of them having the same retention times than those detected in rat and baboon plasma. The third plasma radio-metabolite was suggested to be a carboxylic acid compound that accounted for 15% of the rat brain radioactivity. O-de-ethylation led to a nonradioactive compound and [18F] fluoroacetic acid. Human CYP3A4 and CYP2D6 were shown to be involved in the oxidation of the radioligand. Finally an easy, rapid, and accurate method-indispensable for PET quantitative clinical studies - for quantifying [18F]DPA-714 by solid-phase extraction was developed. In vivo, an extensive metabolism of [18F]DPA-714 was observed in rats and baboons, identified as [18F]de-ethyl, [18F]hydroxyl, and [18F]carboxylic acid derivatives of [18F]DPA-714. The main route of excretion of the unchanged radioligand in baboons was hepatobiliary while that of radio-metabolites was the urinary system. (authors)

  17. Simplifications in analyzing positron emission tomography data: effects on outcome measures

    International Nuclear Information System (INIS)

    Initial validation studies of new radiotracers generally involve kinetic models that require a measured arterial input function. This allows for the separation of tissue binding from delivery and blood flow effects. However, when using a tracer in a clinical setting, it is necessary to eliminate arterial blood sampling due to its invasiveness and the extra burden of counting and analyzing the blood samples for metabolites. In some cases, it may also be necessary to replace dynamic scanning with a shortened scanning period some time after tracer injection, as is done with FDG (F-18 fluorodeoxyglucose). These approximations represent loss of information. In this work, we considered several questions related to this: (1) Do differences in experimental conditions (drug treatments) or populations affect the input function, and what effect, if any, does this have on the final outcome measure? (2) How do errors in metabolite measurements enter into results? (3) What errors are incurred if the uptake ratio is used in place of the distribution volume ratio? (4) Is one- or two-point blood sampling any better for FDG data than the standardized uptake value? and (5) If blood sampling is necessary, what alternatives are there to arterial blood sampling? The first three questions were considered in terms of data from human dynamic positron emission tomography (PET) studies under conditions of baseline and drug pretreatment. Data from [11C]raclopride studies and those from the norepinephrine transporter tracer (S,S)-[11C]O-methyl reboxetine were used. Calculation of a metabolic rate for FDG using the operational equation requires a measured input function. We tested a procedure based on two blood samples to estimate the plasma integral and convolution that occur in the operational equation. There are some tracers for which blood sampling is necessary. Strategies for brain studies involve using the internal carotids in estimating the radioactivity after correcting for partial

  18. Are restrictions to behaviour of patients required following fluorine-18 fluorodeoxyglucose positron emission tomographic studies?

    International Nuclear Information System (INIS)

    The clinical use of positron emission tomography (PET) is expanding rapidly in most European countries. It is likely therefore that patients receiving the tracer fluorine-18 fluorodeoxyglucose (18FDG) will be discharged to come into contact with family members, members of the public and ward staff. There are few direct measurements on which to base any recommendations with regard to radiation protection, and so we have measured the dose rates from patients undergoing clinical PET examinations in our centre. Seventy-five patients who underwent whole-body and brain 18FDG PET examinations were studied. Dose rates were measured at 0.1, 0.5, 1.0 and 2.0 m from the mid thorax on leaving the department. The median administered activity was 323 MBq with a 95th percentile value of 360 MBq. The median dose rates measured at the four distances were 90.0, 35.0, 14.0 and 5.0 μSv h-1 (the median dose rates per unit administered activity at 2 h post injection were 0.31, 0.11, 0.04 and 0.02 μSv h-1 MBq-1). The corresponding 95th percentile values were 174.0, 69.0, 29.0 and 7.5 μSv h-1 (0.43, 0.2, 0.08 and 0.03 μSv h-1 MBq-1). A number of social situations were modelled and an annual dose limit of 1 mSv was used to determine whether restrictive behavioural advice was required. In the case of nursing staff on wards a value of 6 mSv was regarded as the annual limit, which translates to a daily limit of approximately 24 μSv. There is no need for restrictive advice for patients travelling by public or private transport when they leave the department 2 h after the administration of 18FDG. Similarly, there is no need for restrictive advice with regard to their contact with partners, work colleagues or children of any age, although it should be stressed that children should not accompany the patient to the scanning department. The only possible area of concern is in an oncology ward, where patients may be regularly referred for PET investigations and other high activity radionuclide

  19. Reactive astrocytes over express TSPO and are detected by TSPO Positron Emission Tomography Imaging

    International Nuclear Information System (INIS)

    Astrocytes and micro-glia become reactive under most brain pathological conditions, making this neuro-inflammation process a surrogate marker of neuronal dysfunction. Neuro-inflammation is associated with increased levels of translocator protein 18kDa(TSPO) and binding sites for TSPO ligands. Positron emission tomography (PET) imaging of TSPO is thus commonly used to monitor neuro-inflammation in preclinical and clinical studies. It is widely considered that TSPO PET signal reveals reactive micro-glia, although a few studies suggested a potential contribution of reactive astrocytes. Because astrocytes and micro-glia play very different roles, it is crucial to determine whether reactive astrocytes can also over-express TSPO and yield to a detectable TSPO PET signal in vivo. We used a model of selective astrocyte activation through lentiviral gene transfer of the cytokine ciliary neuro-trophic factor (CNTF) into the rat striatum, in the absence of neuro-degeneration. CNTF induced an extensive activation of astrocytes, which over-expressed GFAP and become hypertrophic, whereas micro-glia displayed minimal increase in reactive markers.Two TSPO radioligands, [18F]DPA-714[N,N-diethyl-2-(2-(4-(2-[18F]fluoroethoxy)phenyl) - 5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide] and [11C]SSR180575 (7-chloro-N,N-dimethyl-5-[11C]methyl-4-oxo-3-phenyl - 3,5-dihydro-4H-pyridazino[4,5- b]indole-1-acetamide),showed a significant binding in the lenti-CNTF-injected striatum that was saturated and displaced by PK11195[N-methyl- N-(1-methylpropyl)-1-(2-chlorophenyl)-isoquinoline-3-carboxamide]. The volume of radioligand binding matched the GFAP immuno-positive volume. TSPO mRNA levels were significantly increased, and TSPO protein was over-expressed by CNTF-activated astrocytes. We show that reactive astrocytes over-express TSPO, yielding to a significant and selective binding of TSPO radioligands. Therefore, caution must be used when interpreting TSPO PET imaging in animals or

  20. 18F-Fluoromisonidazole positron emission tomography may differentiate glioblastoma multiforme from less malignant gliomas

    International Nuclear Information System (INIS)

    Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor and its prognosis is significantly poorer than those of less malignant gliomas. Pathologically, necrosis is one of the most important characteristics that differentiate GBM from lower grade gliomas; therefore, we hypothesized that 18F fluoromisonidazole (FMISO), a radiotracer for hypoxia imaging, accumulates in GBM but not in lower grade gliomas. We aimed to evaluate the diagnostic value of FMISO positron emission tomography (PET) for the differential diagnosis of GBM from lower grade gliomas. This prospective study included 23 patients with pathologically confirmed gliomas. All of the patients underwent FMISO PET and 18F-fluorodeoxyglucose (FDG) PET within a week. FMISO images were acquired 4 h after intravenous administration of 400 MBq of FMISO. Tracer uptake in the tumor was visually assessed. Lesion to normal tissue ratios and FMISO uptake volume were calculated. Of the 23 glioma patients, 14 were diagnosed as having GBM (grade IV glioma in the 2007 WHO classification), and the others were diagnosed as having non-GBM (5 grade III and 4 grade II). In visual assessment, all GBM patients showed FMISO uptake in the tumor greater than that in the surrounding brain tissues, whereas all the non-GBM patients showed FMISO uptake in the tumor equal to that in the surrounding brain tissues (p ≤ 0.001). One GBM patient was excluded from FDG PET study because of hyperglycemia. All GBM patients and three of the nine (33%) non-GBM patients showed FDG uptake greater than or equal to that in the gray matter. The sensitivity and specificity for diagnosing GBM were 100 and 100% for FMISO, and 100 and 66% for FDG, respectively. The lesion to cerebellum ratio of FMISO uptake was higher in GBM patients (2.74 ± 0.60, range 1.71-3.81) than in non-GBM patients (1.22 ± 0.06, range 1.09-1.29, p ≤ 0.001) with no overlap between the groups. The lesion to gray matter ratio of FDG was also higher in GBM patients

  1. Mechanisms for the recovery of aphasia following stroke. A positron emission tomography study

    International Nuclear Information System (INIS)

    Language disorders following stroke are common and are a major source of distress and disability. Most patients show some recovery with time implying the potential for neuronal plasticity within the brain for recovery of language. The mechanisms underlying recovery are poorly understood, making strategies for speech therapy and further investigation of potential therapeutic agents difficult. These studies were designed to explore the cortical re-organisation which underlies at least some language recovery using positron emission tomography (PET). With the rapid developments in PET technology and advances in image data processing it is now well established that language tasks can be studied in terms of responses within brain regions, and interactions between regions. The results can be interpreted with reference to neuropsychological theory and models. Many language activation studies have been performed in the normal brain. The studies reported here concentrated on one behavioural task - the verbal fluency task - the strategy being to compare patterns of activation in normal subjects with those in recovered aphasic patients performing the same fluency task. In the first part of this thesis, a detailed PET study of a verb retrieval task was made using different control tasks in normal volunteers. The results show that this task engages a widespread network of regions, predominantly in the left hemisphere i.e. the dorsolateral temporal cortex, the inferolateral temporal cortex and inferior parietal cortex, an extensive area of the dorsolateral prefrontal cortex (LDLPFC), the anterior cingulate and the supplementary motor area (SMA). The experiments using different control tasks suggest that the dorsolateral temporal cortex is involved with auditory and lexical processing of the stimulus nouns and it is demonstrated that observation of an activation in this region is dependent on the particular control task used with the retrieval task. This explains discrepancies

  2. Mechanisms for the recovery of aphasia following stroke. A positron emission tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Warburton, E

    1998-07-01

    Language disorders following stroke are common and are a major source of distress and disability. Most patients show some recovery with time implying the potential for neuronal plasticity within the brain for recovery of language. The mechanisms underlying recovery are poorly understood, making strategies for speech therapy and further investigation of potential therapeutic agents difficult. These studies were designed to explore the cortical re-organisation which underlies at least some language recovery using positron emission tomography (PET). With the rapid developments in PET technology and advances in image data processing it is now well established that language tasks can be studied in terms of responses within brain regions, and interactions between regions. The results can be interpreted with reference to neuropsychological theory and models. Many language activation studies have been performed in the normal brain. Thestudies reported here concentrated on one behavioural task - the verbal fluency task - the strategy being to compare patterns of activation in normal subjects with those in recovered aphasic patients performing the same fluency task. In the first part of this thesis, a detailed PET study of a verb retrieval task was made using different control tasks in normal volunteers. The results show that this task engages a widespread network of regions, predominantly in the left hemisphere i.e. the dorsolateral temporal cortex, the inferolateral temporal cortex and inferior parietal cortex, an extensive area of the dorsolateral prefrontal cortex (LDLPFC), the anterior cingulate and the supplementary motor area (SMA). The experiments using different control tasks suggest that the dorsolateral temporal cortex is involved with auditory and lexical processing of the stimulus nouns and it is demonstrated that observation of an activation in this region is dependent on the particular control task used with the retrieval task. This explains discrepancies

  3. 18F-2-Deoxy-2-Fluoro-D-Glucose Positron Emission Tomography: Computed Tomography for Preoperative Staging in Gastric Cancer Patients

    OpenAIRE

    Youn, Seok Hwa; Seo, Kyung Won; Lee, Sang Ho; Shin, Yeon Myung; Yoon, Ki Young

    2012-01-01

    Purpose The use of 18F-2-deoxy-2-fluoro-D-glucose positron emission tomography-computed tomography as a routine preoperative modality is increasing for gastric cancer despite controversy with its usefulness in preoperative staging. In this study we aimed to determine the usefulness of preoperative positron emission tomography-computed tomography scans for staging of gastric cancer. Materials and Methods We retrospectively analyzed 396 patients' positron emission tomography-computed tomography...

  4. GABA-A stimulation in normal volunteers and during temporal epilepsy measured by 18FDG with positron emission tomography

    International Nuclear Information System (INIS)

    The γ-amino butyric acid (GABA) is the principal inhibitory neurotransmitter of the brain and it has been evoked in epilepto-genesis. Using a GABA analog, the THIP, we tried to establish if the gabaergic neurotransmission was modified in the epileptic focus. For this purpose, we measured the effects of this specific GABA agonist on the cerebral glucose consumption (CMRGlu) as measured by 18F-fluoro-deoxyglucose (18FDG) with positron emission tomography (PET). Eight patients presenting temporal epilepsy and three normal volunteers received two 18FDG PET studies, after placebo and THIP injection, in random order. Clinical symptoms and electroencephalographic data demonstrated a trend towards sleepiness and a diminution of alpha waves after THIP injection. CMRGlu was globally increased with THIP in cortical regions, cerebellum and caudate nuclei. The average increase was 17% in grey matter while it did not reach significancy in white matter. Under the placebo condition, the asymmetry between the focus and the controlateral internal temporal zone was 18% as an average, and reduced significantly to 11% after THIP injection. In the external temporal zones, the asymmetry decreased from 28% to 14%. These results suggest that gabaergic inhibition requires energy in the normal brain tissue and in this with temporal epilepsy. Since the asymmetry of glucose consumption tends to diminish, the inhibitory GABA system appears preserved in temporal epilepsy with an enhanced sensitivity in the focus. (Authors). 6 refs., 4 figs

  5. Synthesis and evaluation of fluorinated derivatives of fentanyl as candidates for opiate receptor studies using positron emission tomography

    International Nuclear Information System (INIS)

    Three fluorinated derivatives of fentanyl, fluorofentanyl (3), keto-fluorofentanyl (5), and fluorofentanol (6), were synthesized and their abilities to compete with 3diprenorphine for binding sites in guinea pig brain membranes were determined. The relative potencies were fentanyl > 3 approx.= 6 >> 5. On the basis of its apparent affinity for opiate receptors and its relative ease of synthesis, 6 was selected for further study. Fentanyl was slightly better than 6 in its ability to compete with [3H]naltrexone for binding sites in rat brain membranes. Both fentayl and 6 exhibited a similar high ''sodium ratio'' (quotient of the IC50's against [3H]naltrexone in the presence and absence of sodium chloride) generally characteristic of opiate agonists. The analgesic potencies of fentanyl and 6 were determined in rats by measuring suppression of locomotion and vocalization responses to footshock. 6 appeared slightly less potent than fentanyl, but produced a similar analgesia and catalepsy which was entirely blocked by pretreatment of rats with naloxone, an opiate antagonist. A rapid synthesis of [18F]-6 was developed and the tissue distribution of [18F]-6 in mice was determined 5, 60, and 120 minutes after intravenous injection. The use of this general route to 18F-labeled derivatives of fentanyl for studies of the opiate receptor using positron emission tomography is planned. (author)

  6. Synthesis and evaluation of fluorinated derivatives of fentanyl as candidates for opiate receptor studies using positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Dahren Hwang; Feliu, A.L.; Wolf, A.P.; MacGregor, R.R.; Fowler, J.S.; Arnett, C.D.

    1986-03-01

    Three fluorinated derivatives of fentanyl, fluorofentanyl (3), keto-fluorofentanyl (5), and fluorofentanol (6), were synthesized and their abilities to compete with /sup 3/diprenorphine for binding sites in guinea pig brain membranes were determined. The relative potencies were fentanyl > 3 approx.= 6 >> 5. On the basis of its apparent affinity for opiate receptors and its relative ease of synthesis, 6 was selected for further study. Fentanyl was slightly better than 6 in its ability to compete with (/sup 3/H)naltrexone for binding sites in rat brain membranes. Both fentayl and 6 exhibited a similar high ''sodium ratio'' (quotient of the IC/sub 50/'s against (/sup 3/H)naltrexone in the presence and absence of sodium chloride) generally characteristic of opiate agonists. The analgesic potencies of fentanyl and 6 were determined in rats by measuring suppression of locomotion and vocalization responses to footshock. 6 appeared slightly less potent than fentanyl, but produced a similar analgesia and catalepsy which was entirely blocked by pretreatment of rats with naloxone, an opiate antagonist. A rapid synthesis of (/sup 18/F)-6 was developed and the tissue distribution of (/sup 18/F)-6 in mice was determined 5, 60, and 120 minutes after intravenous injection. The use of this general route to /sup 18/F-labeled derivatives of fentanyl for studies of the opiate receptor using positron emission tomography is planned.

  7. Preclinical studies on [11C]TMSX for mapping adenosine A2A receptors by positron emission tomography

    International Nuclear Information System (INIS)

    In previous in vivo studies with mice, rats and monkeys, we have demonstrated that [11C]TMSX ([7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)- 1,3,7-trimethylxanthine) is a potential radioligand for mapping adenosine A2A receptors of the brain by positron emission tomography (PET). In the present study, we performed a preclinical study. A suitable preparation method for [11C]TMSX injection was established. The radiation absorbed-dose by [11C]TMSX in humans estimated from the tissue distribution in mice was low enough for clinical use, and the acute toxicity and mutagenicity of TMSX were not found. The striatal uptake of [11C]TMSX in mice was reduced by pretreatment with theophylline at the dose of 10 and 100 mg/kg, suggesting that the [11C]TMSX PET should be carefully performed in the patients received with theophylline. We have concluded that [11C]TMSX is suitable for mapping adenosine A2A receptors in the human brain by PET. (author)

  8. Studies on functional roles of the histaminergic neuron system by using pharmacological agents, knockout mice and positron emission tomography

    International Nuclear Information System (INIS)

    Since one of us, Takehiko Watanabe (TW), elucidated the location and distribution of the histaminergic neuron system in the brain with antibody raised against L-histidine decarboxylase (a histamine-forming enzyme, HDC) as a marker in 1984 and came to Tohoku University School of Medicine in Sendai, we have been collaborating on the functions of this neuron system by using pharmacological agents, knockout mice of the histamine-related genes, and, in some cases, positron emission tomography (PET). Many of our graduate students and colleagues have been actively involved in histamine research since 1985. Our extensive studies have clarified some of the functions of histamine neurons using methods from molecular techniques to non-invasive human PET imaging. Histamine neurons are involved in many brain functions, such as spontaneous locomotion, arousal in wake-sleep cycle, appetite control, seizures, learning and memory, aggressive behavior and emotion. Particularly, the histaminergic neuron system is one of the most important neuron systems to maintain and stimulate wakefulness. Histamine also functions as a biprotection system against various noxious and unfavorable stimuli (for examples, convulsion, nociception, drug sensitization, ischemic lesions, and stress). Although activators of histamine neurons have not been clinically available until now, we would like to point out that the activation of the histaminergic neuron system is important to maintain mental health. Here, we summarize the newly-discovered functions of histamine neurons mainly on the basis of results from our research groups. (author)

  9. Clinico-radiological correlation of Wilson's disease by magnetic resonance imaging, computed tomography and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Ken; Sakata, Chigusa; Nemoto, Hiroshi; Yokoi, Fuji; Sunohara, Nobuhiko (National Center of Neurology and Psychiatry, Kodaira, Tokyo (Japan)); Iio, Masaaki

    1991-02-01

    Five patients with Wilson's disease received repeated magnetic resonance imaging (MRI) and computed tomography (CT) examinations at intervals from 6 to 29 months. Four patients, except for asymptomatic one, also underwent positron emission tomography (PET). The significance and limitations of these imaging modalities were examined in the light of their correlation with clinical manifestations and their therapeutic evaluation. The following focal regions, detected on MRI, had a strong positive correlation with clinical manifestations: the lenticular nuclei for dystonia, the brain stem for abnormality of smooth persuit eye movements, and the caudate and lenticular nuclei for severe dysarthria/dysphagia. Follow-up MRI for 3 patients showed an improvement of findings in the lenticular nuclei, lateral part of the putamen, and brain stem, that was in accordance with improved clinical or neurologic manifestations, such as dystonia and cerebellar symptoms. Severe abnormality in the caudate nucleus was associated with poor prognosis. Repeated CT failed to show serial changes in any of the patients. Regional blood flow and oxygen metabolic rate, obtained by PET examinations, were slightly decreased in the thalamus that had normal findings on both MRI and CT, as well as in the cerebral cortex and basal ganglia. PET was, however, inferior to MRI in detecting fine foci within the basal ganglia. In conclusion, there was a good correlation between MRI findings, particularly foci of the caudate and lenticular nuclei, and clinical manifestations. Repeated MRI examinations were the most useful approach to the evaluation of therapeutic effects and prognosis. (N.K.).

  10. Clinico-radiological correlation of Wilson's disease by magnetic resonance imaging, computed tomography and positron emission tomography

    International Nuclear Information System (INIS)

    Five patients with Wilson's disease received repeated magnetic resonance imaging (MRI) and computed tomography (CT) examinations at intervals from 6 to 29 months. Four patients, except for asymptomatic one, also underwent positron emission tomography (PET). The significance and limitations of these imaging modalities were examined in the light of their correlation with clinical manifestations and their therapeutic evaluation. The following focal regions, detected on MRI, had a strong positive correlation with clinical manifestations: the lenticular nuclei for dystonia, the brain stem for abnormality of smooth persuit eye movements, and the caudate and lenticular nuclei for severe dysarthria/dysphagia. Follow-up MRI for 3 patients showed an improvement of findings in the lenticular nuclei, lateral part of the putamen, and brain stem, that was in accordance with improved clinical or neurologic manifestations, such as dystonia and cerebellar symptoms. Severe abnormality in the caudate nucleus was associated with poor prognosis. Repeated CT failed to show serial changes in any of the patients. Regional blood flow and oxygen metabolic rate, obtained by PET examinations, were slightly decreased in the thalamus that had normal findings on both MRI and CT, as well as in the cerebral cortex and basal ganglia. PET was, however, inferior to MRI in detecting fine foci within the basal ganglia. In conclusion, there was a good correlation between MRI findings, particularly foci of the caudate and lenticular nuclei, and clinical manifestations. Repeated MRI examinations were the most useful approach to the evaluation of therapeutic effects and prognosis. (N.K.)

  11. Quantitative evaluation of regional substrate metabolism in the human heart by positron emission tomography

    International Nuclear Information System (INIS)

    Meaning interpretation of metabolic images obtained by positron emission tomography for evaluation of cardiac disease requires a knowledge of the normal variation in regional myocardial substrate metabolism. Recent studies with fluorine-18 (F-18) fluorodeoxyglucose suggest inhomogeneity of myocardial glucose metabolism in the normal human heart, which may relate to substrate availability. Therefore, quantitative evaluation of myocardial oxidative metabolism and glucose metabolism, as derived by dynamic positron emission tomography with carbon-11 (C-11) acetate and F-18 fluorodeoxyglucose, was performed in nine healthy male volunteers. All were studied under tightly controlled metabolic conditions of hyperinsulinemic-euglycemic clamping with and without a concurrent lipid emulsion infusion. Significant inhomogeneity of regional glucose metabolism was noted although it was less than that described under fasting conditions. Glucose utilization was 13% lower in the septum compared with the lateral wall both without and with lipid infusion (0.34 vs. 0.39 mumol/g per min, respectively, p less than 0.05; and 0.33 vs. 0.38 mumol/g per min, respectively, (p less than 0.05)). Relatively decreased septal glucose utilization could not be explained by decreased metabolic demand because C-11 clearance constants were marginally higher in the septum than in the lateral wall in both studies (0.055 vs. 0.054 per min, respectively, p = NS; and 0.061 vs. 0.056 per min, respectively,(p less than 0.05)). Relatively decreased septal glucose utilization could reflect regional variation in substrate use and possible preferential free fatty acid utilization by the septum. These data provide a useful framework for assessing altered cardiac metabolism in disease and support standardization of metabolic conditions during metabolic imaging with positron emission tomography

  12. Quantitative evaluation of regional substrate metabolism in the human heart by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, R.J.; Herman, W.H.; Kalff, V.; Molina, E.; Wolfe, E.R.; Hutchins, G.; Schwaiger, M. (Department of Internal Medicine, University of Michigan Hospitals, Ann Arbor (USA))

    1991-07-01

    Meaning interpretation of metabolic images obtained by positron emission tomography for evaluation of cardiac disease requires a knowledge of the normal variation in regional myocardial substrate metabolism. Recent studies with fluorine-18 (F-18) fluorodeoxyglucose suggest inhomogeneity of myocardial glucose metabolism in the normal human heart, which may relate to substrate availability. Therefore, quantitative evaluation of myocardial oxidative metabolism and glucose metabolism, as derived by dynamic positron emission tomography with carbon-11 (C-11) acetate and F-18 fluorodeoxyglucose, was performed in nine healthy male volunteers. All were studied under tightly controlled metabolic conditions of hyperinsulinemic-euglycemic clamping with and without a concurrent lipid emulsion infusion. Significant inhomogeneity of regional glucose metabolism was noted although it was less than that described under fasting conditions. Glucose utilization was 13% lower in the septum compared with the lateral wall both without and with lipid infusion (0.34 vs. 0.39 mumol/g per min, respectively, p less than 0.05; and 0.33 vs. 0.38 mumol/g per min, respectively, (p less than 0.05)). Relatively decreased septal glucose utilization could not be explained by decreased metabolic demand because C-11 clearance constants were marginally higher in the septum than in the lateral wall in both studies (0.055 vs. 0.054 per min, respectively, p = NS; and 0.061 vs. 0.056 per min, respectively,(p less than 0.05)). Relatively decreased septal glucose utilization could reflect regional variation in substrate use and possible preferential free fatty acid utilization by the septum. These data provide a useful framework for assessing altered cardiac metabolism in disease and support standardization of metabolic conditions during metabolic imaging with positron emission tomography.

  13. Noninvasive measurement of liver regeneration with positron emission tomography and [2-11C]thymidine

    International Nuclear Information System (INIS)

    The feasibility of liver regeneration determination with [2-11C]thymidine and positron emission tomography was investigated in partially hepatectomized rats. Serial tomographic scans were performed over a 120-minute period after injection of [2-11C]thymidine together with tritium-labeled thymidine. Within 10 minutes after injection, positron emission tomography scans showed a twofold higher hepatic uptake in regenerating than in nonregenerating livers. Time-activity curves over the liver area indicated that the maximal uptake was followed by a faster decrease of 11C radioactivity in controls than in regenerating animals, so that total 11C activity remaining in the liver at 120 minutes accounted for 68% of maximum in regenerating and only 38% in controls. Tissue distribution studies performed at 120 minutes showed that total 11C radioactivity, expressed in percent injected dose per gram, was six times higher in regenerating livers than in controls (0.62% ± 0.07% in regenerating livers and 0.10% ± 0.03% in nonregenerating livers; P less than 0.001) and correlated with 3H radioactivity measured in the nuclear fraction (r = 0.92; P less than 0.001). When the hepatic uptake was expressed in percent of dose per organ, the difference between both groups increased (2.31% ± 0.23% in regenerating livers and 0.29% ± 0.02% in nonregenerating livers; P less than 0.001) because of higher weight of regenerating livers than of nonregenerating livers (3.83 ± 0.11 g in regenerating livers and 2.96 ± 0.16 g in nonregenerating livers; P less than 0.001). In other organs examined, no difference in 11C radioactivity was found between the two groups of rats. These results indicated the potential usefulness of [2-11C]thymidine and positron emission tomography for noninvasive measurement of liver regeneration

  14. FEASIBILITY OF POSITRON EMISSION TOMOGRAPHY OF DOSE DISTRIBUTION IN PROTON BEAM CANCER THERAPY.

    Energy Technology Data Exchange (ETDEWEB)

    BEEBE - WANG,J.J.; DILMANIAN,F.A.; PEGGS,S.G.; SCHLYEER,D.J.; VASKA,P.

    2002-06-03

    Proton therapy is a treatment modality of increasing utility in clinical radiation oncology mostly because its dose distribution conforms more tightly to the target volume than x-ray radiation therapy. One important feature of proton therapy is that it produces a small amount of positron-emitting isotopes along the beam-path through the non-elastic nuclear interaction of protons with target nuclei such as {sup 12}C, {sup 14}N, and {sup 16}O. These radioisotopes, mainly {sup 11}C, {sup 13}N and {sup 15}O, allow imaging the therapy dose distribution using positron emission tomography (PET). The resulting PET images provide a powerful tool for quality assurance of the treatment, especially when treating inhomogeneous organs such as the lungs or the head-and-neck, where the calculation of the dose distribution for treatment planning is more difficult. This paper uses Monte Carlo simulations to predict the yield of positron emitters produced by a 250 MeV proton beam, and to simulate the productions of the image in a clinical PET scanner.

  15. A new positron emission particle tracking facility at iThemba LABS

    International Nuclear Information System (INIS)

    Positron emission particle tracking (PEPT) has become a powerful tool for in-situ characterisation of particulate flow within aggressive industrial environments, such as tumbling mills and powder mixers. PEPT is based on the tracking of a single tracer particle which has been labelled with a radionuclide that decays via β decay. The location of the particle is obtained by the triangulation of events associated with the detection of pairs of annihilation γ rays in a modified 'positron camera'. One of the challenges facing PEPT is associated with labelling sub-millimetre sized particles which would allow studies in systems of finer particulate flow, such as flotation cells. The Positron Imaging Centre at the University of Birmingham is currently the only operational PEPT facility in the world. We are presently installing a PEPT laboratory at the iThemba LABS cyclotron facility in Cape Town. Details of this new facility will be presented, together with a flavour of recent PEPT data obtained in Birmingham, and results from our accelerator-based studies at iThemba LABS which are aimed at extending the state-of-the-art in the size and type of labelled tracer particles for PEPT work. (author)

  16. Human hemispheric infarction studied by positron emission tomography and the 150 continuous inhalation technique

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) offers an entirely new approach to the study of the pathophysiology of cerebral ischemic disorders. This is so because for the first time it is possible to obtain functional tomographic images that represent cerebral perfusion and metabolism in a regional basis. We report here a study of cerebral blood flow and oxygen extraction by means of the 15O inhalation technique in a large number of human hemispheric infarctions. PET imaging with this non-invasive technique has permitted the description of hitherto unreported focal patterns of changes in the CBF/EO2 couple that may have important pathophysiologic and prognostic implications

  17. Whole Body Muscle Activity during the FIFA 11+ Program Evaluated by Positron Emission Tomography

    OpenAIRE

    Nakase, Junsuke; Inaki, Anri; Mochizuki, Takafumi; Toratani, Tatsuhiro; Kosaka, Masahiro; Ohashi, Yoshinori; Taki, Junichi; Yahata, Tetsutaro; Kinuya, Seigo; Tsuchiya, Hiroyuki

    2013-01-01

    Purpose This study investigated the effect of the FIFA 11+ warm-up program on whole body muscle activity using positron emission tomography. Methods Ten healthy male volunteers were divided into a control group and a group that performed injury prevention exercises (The 11+). The subjects of the control group were placed in a sitting position for 20 min and 37 MBq of 18F-fluorodeoxyglucose (FDG) was injected intravenously. The subjects then remained seated for 45 min. The subjects of the exer...

  18. Dead time correction in positron emission tomograph. A method using single photon rate

    Energy Technology Data Exchange (ETDEWEB)

    Senda, Michio; Yonekura, Yoshiharu; Mukai, Takao; Fujita, Toru; Torizuka, Kanji

    1987-06-01

    The count rate linearity and dead time count losses were evaluated in Positologica III, a wholebody multislice positron emission tomograph, using several kinds of phantoms. A wide variation was observed in the relationship between count loss and true coincidence count rate depending on the source distribution, and the dead time correction using the count rate itself was unsuccessful. Since most count losses of this PET scanner occur when the single photon signals were encoded at the circuitry, we measured the single rate to correct for the count loss. This method enabled dead time correction independent of the distribution of source and attenuation material.

  19. Time stamp generation with inverse FIR filters for Positron Emission Tomography

    International Nuclear Information System (INIS)

    Photon coincidence detection is the process by which Positron Emission Tomography (PET) works. This requires the determination of the time of impact of each coincident photon at the detector system, also known as time stamp. In this work, the timestamp was generated by means of digital time-domain deconvolution with FIR filters for a INa(Tl) based system. The detector deadtime was reduced from 350 ns to 175 ns while preserving the system's energy resolution and a direct relation between the amount of light collected and the temporal resolution was found.(author)

  20. Risk of malignancy in thyroid incidentalomas detected by (18)f-fluorodeoxyglucose positron emission tomography

    DEFF Research Database (Denmark)

    Soelberg, Kerstin; Bonnema, Steen Joop; Brix, Thomas Heiberg;

    2012-01-01

    Background: The expanding use of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) has led to the identification of increasing numbers of patients with an incidentaloma in the thyroid gland. We aimed to review the proportion of incidental thyroid cancers found by (18)F-FDG PET...... uptake, 7 of whom (4.4%) had thyroid malignancy. In the eight studies reporting individual maximum standardized uptake values (SUV(max)), the mean SUV(max) was 4.8 (standard deviation [SD] 3.1) and 6.9 (SD 4.7) in benign and malignant lesions, respectively (p...