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Sample records for emission tomography studies

  1. Addiction Studies with Positron Emission Tomography

    SciTech Connect

    Joanna Fowler

    2008-10-13

    Brookhaven scientist Joanna Fowler describes Positron Emission Technology (PET) research at BNL which for the past 30 years has focused in the integration of basic research in radiotracer chemistry with the tools of neuroscience to develop new scientific

  2. Addiction Studies with Positron Emission Tomography

    ScienceCinema

    Joanna Fowler

    2016-07-12

    Brookhaven scientist Joanna Fowler describes Positron Emission Technology (PET) research at BNL which for the past 30 years has focused in the integration of basic research in radiotracer chemistry with the tools of neuroscience to develop new scientific

  3. Studying the pulmonary circulation with positron emission tomography

    SciTech Connect

    Schuster, D.P.; Mintun, M.A.

    1988-01-01

    Positron emission tomography and appropriately labeled, short-lived radiopharmaceuticals can be used to study a variety of physiologic processes within the lung. Recently, methods have been developed to measure regional pulmonary blood flow and pulmonary vascular permeability to protein macromolecules. The advantages of these techniques include accurate quantitation, regional data available in an image format, noninvasiveness, and repeatability. These methods have recently been applied to studies of hypoxic vasoconstriction, pulmonary edema, and chronic obstructive lung disease in man and large experimental animals. Although the technology is complex and requires the integration of people from a variety of disciplines, these methods offer a unique opportunity to study in vivo lung physiology.

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

    SciTech Connect

    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.

  5. Positron emission tomography in the study of hepatic encephalopathy.

    PubMed

    Lockwood, A H

    1998-12-01

    Positron-emission tomography (PET) is a quantitative technique that produces images of biological or physiological processes. The nature of the image depends on the tracer used: common tracers used to study HE include 18F-fluordeoxyglucose, a marker of glucose metabolism; 15O-water, a marker of cerebral blood flow; and 13N-ammonia, a marker of ammonia metabolism. Combined blood flow and ammonia metabolism studies can be used to calculate the permeability surface area product for ammonia at the blood brain barrier. To take full advantage of PET, the data should be analyzed using one of the several sophisticated image processing and analysis techniques that are available. Thus, PET is an ideal technique to evaluate ammonia metabolism and, because of a close linkage of blood flow and glucose metabolism with neural activity, to investigate the neural response to drugs and other treatments and to examine neural systems that mediate specific tasks that are impaired in patients with HE.

  6. Wilson's disease studied with FDG and positron emission tomography

    SciTech Connect

    Hawkins, R.A.; Mazziotta, J.C.; Phelps, M.E.

    1987-11-01

    Four patients with Wilson's disease and eight normal controls were studied with 2-deoxy-2-(/sup 18/F)fluoro-D-glucose (FDG) and positron emission tomography (PET). The patients had diffusely reduced glucose metabolism in all brain regions evaluated compared with controls, with the exception of the thalamus. The ratio of the cerebral metabolic rate for glucose in the lenticular nuclei to hemispheres declined from 1.23 (+/- 0.14 SD) in controls to 1.03 (+/- 0.06) (p less than 0.025) in Wilson's disease patients. Compared with Huntington's disease, the PET FDG results in Wilson's disease indicate relatively less focal involvement of the caudate nucleus, more severe focal changes in the lenticular nuclei, and more significant global changes in glucose metabolism.

  7. Positron emission tomography in the study of human tumors.

    PubMed

    Beaney, R P

    1984-10-01

    To increase our understanding of cancer and improve cancer treatment on a rational basis we need to identify both qualitative and quantitative differences between normal and neoplastic tissue. The multimodality approach to cancer treatment includes radiotherapy, chemotherapy, hyperthermia, and immunotherapy. Most of the data on which we base our therapeutic strategies have been derived from in vitro studies or animal tumor models. More information is required on the physiology of in vivo human tumors and their response to therapy. Positron emission tomography allows the regional tissue concentration of a positron emitting radionuclide to be measured in absolute units. If valid tracer models can be formulated that accurately describe the fate of an administered "biological" tracer then the physiological process under investigation can be measured quantitatively. The sequential inhalation of C15O2, 15O2, and 11CO allows regional tissue blood flow, oxygen utilization and blood volume to be measured in absolute units. Tissue perfusion, a measure of nutrient (eg, oxygen) supply, drug delivery, or a means of heat dissipation, is of immense importance to oncologists. The oxygen-15 technique has been used not only to study regional blood flow and oxygen utilization in both tumor and normal tissue but also their response to therapeutic intervention. In those studies were tracer models are thought to be less than complete (eg, due to insufficient biological data) then only a semiquantitative or qualitative assessment of the pathophysiological state may be possible. In this respect, tumor function has been characterized by the rate of uptake of 18F-2-deoxyglucose. This technique has provided a means of tumor grading and differentiating between radiation-induced tissue necrosis and tumor recurrence. Metabolic imaging with labeled amino acids appears particularly useful in the delineation of tumor extent. Blood brain barrier integrity and the pharmacokinetics of cytotoxic drugs

  8. Simulation study of respiratory-induced errors in cardiac positron emission tomography/computed tomography

    SciTech Connect

    Fitzpatrick, Gianna M.; Wells, R. Glenn

    2006-08-15

    Heart disease is a leading killer in Canada and positron emission tomography (PET) provides clinicians with in vivo metabolic information for diagnosing heart disease. Transmission data are usually acquired with {sup 68}Ge, although the advent of PET/CT scanners has made computed tomography (CT) an alternative option. The fast data acquisition of CT compared to PET may cause potential misregistration problems, leading to inaccurate attenuation correction (AC). Using Monte Carlo simulations and an anthropomorphic dynamic computer phantom, this study determines the magnitude and location of respiratory-induced errors in radioactivity uptake measured in cardiac PET/CT. A homogeneous tracer distribution in the heart was considered. The AC was based on (1) a time-averaged attenuation map (2) CT maps from a single phase of the respiratory cycle, and (3) CT maps phase matched to the emission data. Circumferential profiles of the heart uptake were compared and differences of up to 24% were found between the single-phase CT-AC method and the true phantom values. Simulation results were supported by a PET/CT canine study which showed differences of up to 10% in the heart uptake in the lung-heart boundary region when comparing {sup 68}Ge- to CT-based AC with the CT map acquired at end inhalation.

  9. Eyeblink Conditioning in Healthy Adults: A Positron Emission Tomography Study

    PubMed Central

    Andreasen, Nancy C.; Liu, Dawei; Freeman, John H.; Boles Ponto, Laura L.; O’Leary, Daniel S.

    2013-01-01

    Eyeblink conditioning is a paradigm commonly used to investigate the neural mechanisms underlying motor learning. It involves the paired presentation of a toneconditioning stimulus which precedes and co-terminates with an airpuff unconditioned stimulus. Following repeated paired presentations a conditioned eyeblink develops which precedes the airpuff. This type of learning has been intensively studied and the cerebellum is known to be essential in both humans and animals. The study presented here was designed to investigate the role of the cerebellum during eyeblink conditioning in humans using positron emission tomography (PET). The sample includes 20 subjects (10 male and 10 female) with an average age of 29.2 years. PET imaging was used to measure regional cerebral blood flow (rCBF) changes occurring during the first, second, and third blocks of conditioning. In addition, stimuli-specific rCBF to unpaired tones and airpuffs (“pseudoconditioning”) was used as a baseline level that was subtracted from each block. Conditioning was performed using three, 15-trial blocks of classical eyeblink conditioning with the last five trials in each block imaged. As expected, subjects quickly acquired conditioned responses. A comparison between the conditioning tasks and the baseline task revealed that during learning there was activation of the cerebellum and recruitment of several higher cortical regions. Specifically, large peaks were noted in cerebellar lobules IV/V, the frontal lobes, and cingulate gyri. PMID:22430943

  10. Simulation Study of Single Photon Emission Computed Tomography for Industrial Applications

    SciTech Connect

    Roy, Tushar; Sarkar, P. S.; Sinha, Amar

    2008-09-26

    SPECT (Single Photon Emission Computed Tomography) provides for an invaluable non-invasive technique for the characterization and activity distribution of the gamma-emitting source. For many applications of radioisotopes for medical and industrial application, not only the positional information of the distribution of radioisotopes is needed but also its strength. The well-established X-ray radiography or transmission tomography techniques do not yield sufficient quantitative information about these objects. Emission tomography is one of the important methods for such characterization. Application of parallel beam, fan beam and 3D cone beam emission tomography methods have been discussed in this paper. Simulation studies to test these algorithms have been carried out to validate the technique.

  11. Positron Emission Tomography.

    PubMed

    Lameka, Katherine; Farwell, Michael D; Ichise, Masanori

    2016-01-01

    Positron emission tomography (PET) is a minimally invasive imaging procedure with a wide range of clinical and research applications. PET allows for the three-dimensional mapping of administered positron-emitting radiopharmaceuticals such as (18)F-fluorodeoxyglucose (for imaging glucose metabolism). PET enables the study of biologic function in both health and disease, in contrast to magnetic resonance imaging (MRI) and computed tomography (CT), that are more suited to study a body's morphologic changes, although functional MRI can also be used to study certain brain functions by measuring blood flow changes during task performance. This chapter first provides an overview of the basic physics principles and instrumentation behind PET methodology, with an introduction to the merits of merging functional PET imaging with anatomic CT or MRI imaging. We then focus on clinical neurologic disorders, and reference research on relevant PET radiopharmaceuticals when applicable. We then provide an overview of PET scan interpretation and findings in several specific neurologic disorders such as dementias, epilepsy, movement disorders, infection, cerebrovascular disorders, and brain tumors. PMID:27432667

  12. Cardiac Positron Emission Tomography

    PubMed Central

    Geltman, Edward M.

    1985-01-01

    Positron emission tomography (PET) is a new technique for noninvasively assessing myocardial metabolism and perfusion. It has provided new insight into the dynamics of myocardial fatty acid and glucose metabolism in normal subjects, patients with ischemic heart disease and those with cardiomyopathies, documenting regionally depressed fatty acid metabolism during myocardial ischemia and infarction and spatial heterogeneity of fatty acid metabolism in patients with cardiomyopathy. Regional myocardial perfusion has been studied with PET using water, ammonia and rubidium labeled with positron emitters, permitting the noninvasive detection of hypoperfused zones at rest and during vasodilator stress. With these techniques the relationship between perfusion and the metabolism of a variety of substrates has been studied. The great strides that have been made in developing faster high-resolution instruments and producing new labeled intermediates indicate the promise of this technique for facilitating an increase in the understanding of regional metabolism and blood flow under normal and pathophysiologic conditions. ImagesFigure 5.Figure 6.Figure 7.Figure 8.Figure 9. PMID:3879048

  13. Positron Emission Tomography (PET)

    SciTech Connect

    Welch, M.J.

    1990-01-01

    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 (PET)

    DOE R&D Accomplishments Database

    Welch, M. J.

    1990-01-01

    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.

  15. Brain single photon emission computed tomography: Newer activation and intervention studies

    SciTech Connect

    Tikofsky, R.S.; Hellman, R.S. )

    1991-01-01

    Single-photon emission computed tomography (SPECT) regional cerebral blood flow (rCBF) findings using non-xenon 133 tracers in combination with activation and intervention techniques are reviewed. Examination of the currently available data indicates that it is possible to detect the effects of a variety of activations and interventional procedures using SPECT rCBF with non-xenon 133 tracers. There are still many issues to be resolved before SPECT can reach the level of sophistication attained by xenon 133 and positron emission tomography in studying rCBF during activation or intervention. However, research to date indicates that SPECT rCBF studied with tracers other than xenon 133 has an excellent potential for increasing the ability to differentiate normal and pathological states. 97 refs.

  16. Generalized local emission tomography

    DOEpatents

    Katsevich, Alexander J.

    1998-01-01

    Emission tomography enables locations and values of internal isotope density distributions to be determined from radiation emitted from the whole object. In the method for locating the values of discontinuities, the intensities of radiation emitted from either the whole object or a region of the object containing the discontinuities are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the isotope density discontinuity. The asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) is determined in a neighborhood of S, and the value for the discontinuity is estimated from the asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) knowing pointwise values of the attenuation coefficient within the object. In the method for determining the location of the discontinuity, the intensities of radiation emitted from an object are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the density discontinuity and the location .GAMMA. of the attenuation coefficient discontinuity. Pointwise values of the attenuation coefficient within the object need not be known in this case.

  17. Evaluation of dosimetry and image of very low-dose computed tomography attenuation correction for pediatric positron emission tomography/computed tomography: phantom study

    NASA Astrophysics Data System (ADS)

    Bahn, Y. K.; Park, H. H.; Lee, C. H.; Kim, H. S.; Lyu, K. Y.; Dong, K. R.; Chung, W. K.; Cho, J. H.

    2014-04-01

    In this study, phantom was used to evaluate attenuation correction computed tomography (CT) dose and image in case of pediatric positron emission tomography (PET)/CT scan. Three PET/CT scanners were used along with acryl phantom in the size for infant and ion-chamber dosimeter. The CT image acquisition conditions were changed from 10 to 20, 40, 80, 100 and 160 mA and from 80 to 100, 120 and 140 kVp, which aimed at evaluating penetrate dose and computed tomography dose indexvolume (CTDIvol) value. And NEMA PET Phantom™ was used to obtain PET image under the same CT conditions in order to evaluate each attenuation-corrected PET image based on standard uptake value (SUV) value and signal-to-noise ratio (SNR). In general, the penetrate dose was reduced by around 92% under the minimum CT conditions (80 kVp and 10 mA) with the decrease in CTDIvol value by around 88%, compared with the pediatric abdomen CT conditions (100 kVp and 100 mA). The PET image with its attenuation corrected according to each CT condition showed no change in SUV value and no influence on the SNR. In conclusion, if the minimum dose CT that is properly applied to body of pediatric patient is corrected for attenuation to ensure that the effective dose is reduced by around 90% or more compared with that for adult patient, this will be useful to reduce radiation exposure level.

  18. Improving 18F-Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography Imaging in Alzheimer's Disease Studies

    PubMed Central

    Knešaurek, Karin

    2015-01-01

    The goal was to improve Alzheimer's 2-deoxy-2-18F-fluoro-D-glucose (18F FDG)-positron emission tomography (PET)/computed tomography (CT) imaging through application of a novel, hybrid Fourier-wavelet windowed Fourier transform (WFT) restoration technique, in order to provide earlier and more accurate clinical results. General Electric Medical Systems downward-looking sonar PET/CT 16 slice system was used to acquire studies. Patient data were acquired according the Alzheimer's disease Neuroimaging Initiative (ADNI) protocol. Here, we implemented Fourier-wavelet regularized restoration, with a Butterworth low-pass filter, order n = 6 and a cut-off frequency f = 0.35 cycles/pixel and wavelet (Daubechies, order 2) noise suppression. The original (PET-O) and restored (PET-R) ADNI subject PET images were compared using the Alzheimer's discrimination analysis by dedicated software. Forty-two PET/CT scans were used in the study. They were performed on eleven ADNI subjects at intervals of approximately 6 months. The final clinical diagnosis was used as a gold standard. For three subjects, the final clinical diagnosis was mild cognitive impairment and those 13 PET/CT studies were not included in the final comparison, as the result was considered as inconclusive. Using the reminding 29 PET/CT studies (23 AD and 6 normal), the sensitivity and specificity of the PET-O and PET-R were calculated. The sensitivity was 0.65 and 0.96 for PET-O and PET-R, respectively, and the specificity was 0.67 and 0.50 for PET-O and PET-R. The accuracy was 0.66 and 0.86 for PET-O and PET-R, respectively. The results of the study demonstrated that the accuracy of three-dimensional brain F-18 FDG PET images was significantly improved by Fourier-wavelet restoration filtering. PMID:26420987

  19. Improving (18)F-Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography Imaging in Alzheimer's Disease Studies.

    PubMed

    Knešaurek, Karin

    2015-01-01

    The goal was to improve Alzheimer's 2-deoxy-2-(18)F-fluoro-D-glucose ((18)F FDG)-positron emission tomography (PET)/computed tomography (CT) imaging through application of a novel, hybrid Fourier-wavelet windowed Fourier transform (WFT) restoration technique, in order to provide earlier and more accurate clinical results. General Electric Medical Systems downward-looking sonar PET/CT 16 slice system was used to acquire studies. Patient data were acquired according the Alzheimer's disease Neuroimaging Initiative (ADNI) protocol. Here, we implemented Fourier-wavelet regularized restoration, with a Butterworth low-pass filter, order n = 6 and a cut-off frequency f = 0.35 cycles/pixel and wavelet (Daubechies, order 2) noise suppression. The original (PET-O) and restored (PET-R) ADNI subject PET images were compared using the Alzheimer's discrimination analysis by dedicated software. Forty-two PET/CT scans were used in the study. They were performed on eleven ADNI subjects at intervals of approximately 6 months. The final clinical diagnosis was used as a gold standard. For three subjects, the final clinical diagnosis was mild cognitive impairment and those 13 PET/CT studies were not included in the final comparison, as the result was considered as inconclusive. Using the reminding 29 PET/CT studies (23 AD and 6 normal), the sensitivity and specificity of the PET-O and PET-R were calculated. The sensitivity was 0.65 and 0.96 for PET-O and PET-R, respectively, and the specificity was 0.67 and 0.50 for PET-O and PET-R. The accuracy was 0.66 and 0.86 for PET-O and PET-R, respectively. The results of the study demonstrated that the accuracy of three-dimensional brain F-18 FDG PET images was significantly improved by Fourier-wavelet restoration filtering.

  20. High-resolution PET (positron emission tomography) for medical science studies

    SciTech Connect

    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. 6 refs., 21 figs.

  1. High-resolution PET [Positron Emission Tomography] for Medical Science Studies

    DOE R&D Accomplishments Database

    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.

  2. Positron emission tomography - a new approach to brain chemistry

    SciTech Connect

    Jacobson, H.G.

    1988-11-11

    Positron emission tomography permits examination of the chemistry of the brain in living beings. Until recently, positron emission tomography had been considered a research tool, but it is rapidly moving into clinical practice. This report describes the uses and applications of positron emission tomography in examinations of patients with strokes, epilepsy, malignancies, dementias, and schizophrenia and in basic studies of synaptic neurotransmission.

  3. The nigrostriatal dopaminergic pathway in Wilson's disease studied with positron emission tomography.

    PubMed Central

    Snow, B J; Bhatt, M; Martin, W R; Li, D; Calne, D B

    1991-01-01

    Movement disorders, including Parkinsonism, are prominent features of neurological Wilson's disease (WD). This suggests there may be dysfunction of the nigrostriatal dopaminergic pathway. To explore this possibility, five patients were studied using positron emission tomography (PET) with 18F-6-fluorodopa (6FD), and magnetic resonance imaging (MRI). We calculated striatal 6FD uptake rate constants by a graphical method and compared the results with those of 18 normal subjects. It was found that four patients with symptoms all had abnormally low 6FD uptake, and the one asymptomatic patient had normal uptake. PET evidence for nigrostriatal dopaminergic dysfunction was present even after many years of penicillamine treatment. It is concluded that the nigrostriatal dopaminergic pathway is involved in neurological WD. Images PMID:1901347

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

    SciTech Connect

    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.

  5. Zolpidem-Induced Arousal by Paradoxical GABAergic Stimulation: A Case Report With F-18 Flumazenil Positron Emission Tomography and Single Photon Emission Computed Tomography Study

    PubMed Central

    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

  6. Cognitive processes and cerebral cortical fundi: findings from positron-emission tomography studies.

    PubMed Central

    Markowitsch, H J; Tulving, E

    1994-01-01

    Positron-emission tomography (PET) studies of regional cerebral blood flow have provided evidence relevant to localization of cognitive functions. The critical loci identified in these studies are typically described in terms of macroanatomically labeled cortical and subcortical regions. We report the results of a meta-analysis of localization of changes in blood flow, based on nearly 1000 cerebral cortical peaks of activity obtained from groups of subjects in 30 PET studies. The results showed that, on average, 47% of these peaks were localized within the fundus regions of cortical sulci. This is an unexpectedly high proportion because fundal regions compose < 8% of the cortical mantle. Further analysis suggested a coarse correlation between the extent of fundal activation observed in different studies and the estimated cognitive complexity of the tasks used in the studies. These findings are potentially interesting because (i) the preponderance of fundal activation has implications for the interpretation of the PET data, (ii) they suggest that cortical sulcal and fundal regions may play a distinctive role in higher cognitive processing, or (iii) both of the above. PMID:7937984

  7. Eyeblink conditioning in unmedicated schizophrenia patients: A positron emission tomography study

    PubMed Central

    Parker, Krystal L.; Andreasen, Nancy C.; Liu, Dawei; Freeman, John H.; O’Leary, Daniel S.

    2014-01-01

    Previous studies suggest that patients with schizophrenia exhibit dysfunctions in a widely distributed circuit—the cortico-cerebellar-thalamic-cortical circuit, or CCTCC—and that this may explain the multiple cognitive deficits observed in the disorder. This study uses positron emission tomography (PET) with O15 H2O to measure regional cerebral blood flow (rCBF) in response to a classic test of cerebellar function, the associative learning that occurs during eyeblink conditioning, in a sample of 20 unmedicated schizophrenia patients and 20 closely matched healthy controls. The PET paradigm examined three phases of acquisition and extinction (early, middle and late). The patients displayed impaired behavioral performance during both acquisition and extinction. The imaging data indicate that, compared to the control subjects, the patients displayed decreases in rCBF in all three components of the CCTCC during both acquisition and extinction. Specifically, patients had less rCBF in the middle and medial frontal lobes, anterior cerebellar lobules I/V and VI, as well as the thalamus during acquisition and although similar areas were found in the frontal lobe, ipsilateral cerebellar lobule IX showed consistently less activity in patients during extinction. Thus this study provides additional support for the hypothesis that patients with schizophrenia have a cognitive dysmetria—an inability to smoothly coordinate many different types of mental activity—that affects even a very basic cognitive task that taps into associative learning. PMID:24090512

  8. Neural correlates of sensorimotor gating: a metabolic positron emission tomography study in awake rats.

    PubMed

    Rohleder, Cathrin; Jung, Fabienne; Mertgens, Hanna; Wiedermann, Dirk; Sué, Michael; Neumaier, Bernd; Graf, Rudolf; Leweke, F Markus; Endepols, Heike

    2014-01-01

    Impaired sensorimotor gating occurs in neuropsychiatric disorders such as schizophrenia and can be measured using the prepulse inhibition (PPI) paradigm of the acoustic startle response. This assay is frequently used to validate animal models of neuropsychiatric disorders and to explore the therapeutic potential of new drugs. The underlying neural network of PPI has been extensively studied with invasive methods and genetic modifications. However, its relevance for healthy untreated animals and the functional interplay between startle- and PPI-related areas during a PPI session is so far unknown. Therefore, we studied awake rats in a PPI paradigm, startle control and background noise control, combined with behavioral [(18)F]fluoro-2-deoxyglucose positron emission tomography (FDG-PET). Subtractive analyses between conditions were used to identify brain regions involved in startle and PPI processing in well-hearing Black hooded rats. For correlative analysis with regard to the amount of PPI we also included hearing-impaired Lister hooded rats that startled more often, because their hearing threshold was just below the lowest prepulses. Metabolic imaging showed that the brain areas proposed for startle and PPI mediation are active during PPI paradigms in healthy untreated rats. More importantly, we show for the first time that the whole PPI modulation network is active during "passive" PPI sessions, where no selective attention to prepulse or startle stimulus is required. We conclude that this reflects ongoing monitoring of stimulus significance and constant adjustment of sensorimotor gating.

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

    SciTech Connect

    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. )

    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.

  10. Neural correlates of sensorimotor gating: a metabolic positron emission tomography study in awake rats

    PubMed Central

    Rohleder, Cathrin; Jung, Fabienne; Mertgens, Hanna; Wiedermann, Dirk; Sué, Michael; Neumaier, Bernd; Graf, Rudolf; Leweke, F. Markus; Endepols, Heike

    2014-01-01

    Impaired sensorimotor gating occurs in neuropsychiatric disorders such as schizophrenia and can be measured using the prepulse inhibition (PPI) paradigm of the acoustic startle response. This assay is frequently used to validate animal models of neuropsychiatric disorders and to explore the therapeutic potential of new drugs. The underlying neural network of PPI has been extensively studied with invasive methods and genetic modifications. However, its relevance for healthy untreated animals and the functional interplay between startle- and PPI-related areas during a PPI session is so far unknown. Therefore, we studied awake rats in a PPI paradigm, startle control and background noise control, combined with behavioral [18F]fluoro-2-deoxyglucose positron emission tomography (FDG-PET). Subtractive analyses between conditions were used to identify brain regions involved in startle and PPI processing in well-hearing Black hooded rats. For correlative analysis with regard to the amount of PPI we also included hearing-impaired Lister hooded rats that startled more often, because their hearing threshold was just below the lowest prepulses. Metabolic imaging showed that the brain areas proposed for startle and PPI mediation are active during PPI paradigms in healthy untreated rats. More importantly, we show for the first time that the whole PPI modulation network is active during “passive” PPI sessions, where no selective attention to prepulse or startle stimulus is required. We conclude that this reflects ongoing monitoring of stimulus significance and constant adjustment of sensorimotor gating. PMID:24904330

  11. Dynamic study of methionine positron emission tomography in patients with glioblastoma with oligodendroglial components.

    PubMed

    Yano, Hirohito; Ohe, Naoyuki; Nakayama, Noriyuki; Nomura, Yu-Ichi; Miwa, Kazuhiro; Shinoda, Jun; Iwama, Toru

    2015-10-01

    Anaplastic oligoastrocytoma (AOA) with necrosis is classified as glioblastoma (GBM) with oligodendroglioma component (GBMO), according to the 2007 World Health Organization classification. The prognosis of GBMO remains controversial because definitive diagnostic criteria regarding the percentage of the oligodendroglial components (OC) in the GBM do not exist. We previously reported dynamic methionine (MET) positron emission tomography (PET) in patients with these tumors. A significant decrease in the MET signal was seen in oligodendrocytic tumors, in contrast to a significant MET increase in GBMs. In this study, we analyzed the dynamic MET PET signal in four patients with primary (n = 2) and secondary (n = 2) GBMOs. Static PET scanning was performed in three consecutive phases. Both cases of primary GBMOs and one case of secondary GBMO presented with a gradual decrease in MET PET signal over the consecutive phases. In contrast, the remaining case of secondary GBMO presented with a pattern of slight increase. It is likely that the dynamic change of MET in patients with GBMO resemble those in patients with oligodendroglial tumor, however, further studies are needed to confirm them. We discuss the mechanisms from a viewpoint of pathological findings.

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

    SciTech Connect

    Kuhl, D.E.

    1989-11-01

    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.

  13. The role of pallidal serotonergic function in Parkinson's disease dyskinesias: a positron emission tomography study.

    PubMed

    Smith, Ruben; Wu, Kit; Hart, Thomas; Loane, Clare; Brooks, David J; Björklund, Anders; Odin, Per; Piccini, Paola; Politis, Marios

    2015-04-01

    We have investigated the role of globus pallidus (GP) serotonergic terminals in the development of levodopa-induced dyskinesias (LIDs) in Parkinson's disease (PD). We studied 12 PD patients without LIDs, 12 PD patients with LIDs, and 12 healthy control subjects. We used (11)C-DASB positron emission tomography (PET), a marker of serotonin transporter availability, and (11)C-raclopride PET to measure changes in synaptic dopamine levels following levodopa administration. PD patients without LIDs showed a significant reduction of GP serotonin transporter binding compared with healthy controls although this was within the normal range in PD patients with LIDs. Levels of GP serotonin transporter binding correlated positively with severity of dyskinesias. (11)C-raclopride PET detected a significant rise in GP synaptic dopamine levels of patients with LIDs after a levodopa challenge but not in patients with a stable response. Our findings indicate that LIDs in PD are associated with higher GP serotonergic function. This increased serotonin function may result in further dysregulation of thalamocortical signals and so promote the expression of dyskinesias. PMID:25649022

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

    PubMed

    Park, So Hyeon; Park, Hyun Soo; Kim, Sang Eun

    2016-08-01

    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 (18)F-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

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

    PubMed Central

    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

  16. Functional reorganisation of memory after traumatic brain injury: a study with H2150 positron emission tomography

    PubMed Central

    Levine, B; Cabeza, R; McIntosh, A; Black, S; Grady, C; Stuss, D

    2002-01-01

    Objective: To study the effects of moderate to severe traumatic brain injury (TBI) on the functional neuroanatomy supporting memory retrieval. Methods: Subjects were six patients who had sustained a moderate to severe TBI about four years before scanning and had since made a good recovery. Eleven healthy young adults matched to the patients for age and education served as controls. An established H2150 positron emission tomography paradigm was used to elicit brain activations in response to memory retrieval. TBI patients' patterns of brain activation were compared statistically with those of control subjects. Both group and individual case data were analysed. Results: Both TBI patients and controls engaged frontal, temporal, and parietal regions known to be involved in memory retrieval, yet the TBI patients showed relative increases in frontal, anterior cingulate, and occipital activity. The hemispheric asymmetry characteristic of controls was attenuated in patients with TBI. Reduced activation was noted in the right dorsomedial thalamus. Although local aspects of this pattern were affected by the presence of focal lesions and performance differences, the overall pattern was reliable across patients and comparable to functional neuroimaging results reported for normal aging, Alzheimer's disease, and other patients with TBI. Conclusions: The TBI patients performed memory tasks using altered functional neuroanatomical networks. These changes are probably the result of diffuse axonal injury and may reflect either cortical disinhibition attributable to disconnection or compensation for inefficient mnemonic processes. PMID:12122177

  17. F-18 Fluorodeoxyglucose Positron Emission Tomography study of Impaired Emotion Processing in First Episode Schizophrenia

    PubMed Central

    Choudhary, Mona; Kumar, Arvind; Tripathi, Madhavi; Bhatia, Triptish; Shivakumar, Venkataram; Beniwal, Ram Pratap; Gur, Ruben C.; Gur, Raquel E.; Nimgaonkar, Vishwajit L.

    2015-01-01

    Background Schizophrenia cases have consistently shown to have behavioural and neurofunctional abnormalities but studies during early course are scarce. The present work assesses the performance of acute first episode schizophrenia cases on correlation of a facial emotion perception task with brain function using Fluorine-18 Fluorodeoxyglucose (FDG) positron emission tomography (PET). Methods Twenty First episode schizophrenia cases and 20 matched healthy controls living in the community were enrolled. For cases, longest duration of illness was one year and treatment with neuroleptic did not exceed two weeks on the day of scan. To measure facial emotion perception (FEP) both groups were administered the Emotion battery from the Penn Computerized Battery followed by PET acquisition. SPM 8 analysis for group differences at p<0.001 was performed. Results Schizophrenia subjects showed hypoactivation of bilateral prefrontal cortices and fusiform gyrii, with significant hyperactivation of bilateral basal ganglia and left precuneus. Positive correlation of metabolism in prefrontal cortex and performance indices on emotions domain was seen. No correlation of CPZ equivalent days with metabolism in basal ganglia was observed. Conclusions The performance of schizophrenia cases on FEP task was significantly impaired in comparison to the control group. Brain regions implicated in emotion processing showed hypometabolism in cases as compared to controls. Failure of schizophrenia cases to optimally recruit brain circuitry may be contributing to deficits on FEP task. These findings suggest inherent deficits in neural circuitry of emotion processing in schizophrenia; devoid of confounding effects of neuroleptics and duration of illness. PMID:25655909

  18. Hemiballismus: Study of a case using positron emission tomography with 18fluoro-2-deoxyglucose

    SciTech Connect

    Dubinsky, R.M.; Greenberg, M.; Di Chiro, G.; Baker, M.; Hallett, M. )

    1989-01-01

    A 64-year-old man had right-sided persistent hemiballismus. Cerebral computed tomography (CT) and 0.5-T magnetic resonance imaging (MRI) showed no abnormalities, but 1.5-T MRI showed decreased signal intensity of the putamina, greater on the left than on the right. The subthalamic area was normal on CT and MRI. Positron emission tomography with 18fluoro2-deoxyglucose showed marked hypometabolism of the left putamen (60% of the right) and hypermetabolism of the left parietal lobe (138% of the right). The decreased metabolism of the left putamen may indicate a reduction in neuronal firing. The pathophysiology of the hemiballismus in this case may be loss of tonic inhibition of the lateral globus pallidus from the putamen, leading in turn to greater inhibition of the subthalamic nucleus, less excitation of the medial globus pallidus, and less inhibition of the thalamus and motor cortex, and thus allowing expression of the ballistic movements.

  19. Using positron emission tomography to study human ketone body metabolism: a review.

    PubMed

    Bouteldja, Nadia; Andersen, Lone Thing; Møller, Niels; Gormsen, Lars Christian

    2014-11-01

    Ketone bodies - 3-hydroxybutyrate and acetoacetate - are important fuel substrates, which can be oxidized by most tissues in the body. They are synthesized in the liver and are derived from fatty acids released from adipose tissue. Intriguingly, under conditions of stress such as fasting, arterio-venous catheterization studies have shown that the brain switches from the use of almost 100% glucose to the use of >50-60% ketone bodies. A similar adaptive mechanism is observed in the heart, where fasting induces a shift toward ketone body uptake that provides the myocardium with an alternate fuel source and also favorably affects myocardial contractility. Within the past years there has been a renewed interest in ketone bodies and the possible beneficial effects of fasting/semi-fasting/exercising and other "ketogenic" regimens have received much attention. In this perspective, it is promising that positron emission tomography (PET) techniques with isotopically labeled ketone bodies, fatty acids and glucose offer an opportunity to study interactions between ketone body, fatty acid and glucose metabolism in tissues such as the brain and heart. PET scans are non-invasive and thus eliminates the need to place catheters in vascular territories not easily accessible. The short half-life of e.g. 11C-labeled PET tracers even allows multiple scans on the same study day and reduces the total radiation burden associated with the procedure. This short review aims to give an overview of current knowledge on ketone body metabolism obtained by PET studies and discusses the methodological challenges and perspectives involved in PET ketone body research. PMID:25195069

  20. Effects of amphetamine on the human brain opioid system--a positron emission tomography study.

    PubMed

    Guterstam, Joar; Jayaram-Lindström, Nitya; Cervenka, Simon; Frost, J James; Farde, Lars; Halldin, Christer; Franck, Johan

    2013-05-01

    Studies in rodents have shown that psychostimulant drugs such as cocaine and amphetamine cause endorphin release in the brain reward system. There is also evidence for the involvement of the opioid system in human psychostimulant dependence. The acute effects of an i.v. psychostimulant drug on the brain opioid system, however, have not yet been investigated in humans. We hypothesized that an i.v. dose of amphetamine as compared to placebo would cause an opioid release in the human brain reward system, measurable as a reduction of the binding potential of the μ-opioid receptor radioligand [(11)C]carfentanil. Ten healthy young men were examined using positron emission tomography (PET) and [(11)C]carfentanil in three sessions: at baseline; after placebo; after an i.v. amphetamine dose of 0.3 mg/kg bodyweight. The order of amphetamine and placebo was double-blinded and randomized. PET examinations were performed with a Siemens high resolution research tomograph. Data were analysed with the simplified reference tissue model, applying manually drawn regions of interest for every subject. Using repeated measures analysis of variance, we found no significant differences in [(11)C]carfentanil binding potential between amphetamine and placebo conditions in any of the investigated brain regions. In contrast to data from rodent studies and a recent study of oral amphetamine administration in humans, an i.v. dose of amphetamine does not cause any acute opioid release in healthy human subjects. The postulated role of the opioid system in mediating the effects of amphetamine needs to be further investigated in animal models of the disease as well as in patient populations.

  1. Using Positron Emission Tomography to Study Transporter-Mediated Drug–Drug Interactions in Tissues

    PubMed Central

    Wulkersdorfer, B; Wanek, T; Bauer, M; Zeitlinger, M; Müller, M; Langer, O

    2014-01-01

    Drug disposition is highly regulated by membrane transporters. Some transporter-mediated drug–drug interactions (DDIs) may not manifest themselves in changes in systemic exposure but rather in changes in tissue exposure of drugs. To better assess the impact of transporter-mediated DDIs in tissues, positron emission tomography (PET)—a noninvasive imaging method—plays an increasingly important role. In this article, we provide examples of how PET can be used to assess transporter-mediated DDIs in different organs. PMID:24682030

  2. Painful spondylolysis or spondylolisthesis studied by radiography and single-photon emission computed tomography

    SciTech Connect

    Collier, B.D.; Johnson, R.P.; Carrera, G.F.; Meyer, G.A.; Schwab, J.P.; Flatley, T.J.; Isitman, A.T.; Hellman, R.S.; Zielonka, J.S.; Knobel, J.

    1985-01-01

    Planar bone scintigraphy (PBS) and single-photon emission computed tomography (SPECT) were compared in 19 adults with radiographic evidence of spondylolysis and/or spondylolisthesis. SPECT was more sensitive than PBS when used to identify symptomatic patients and sites of painful defects in the pars interarticularis. In addition, SPECT allowed more accurate localization than PBS. In 6 patients, spondylolysis or spondylolisthesis was unrealted to low back pain, and SPECT images of the posterior neural arch were normal. The authors conclude that when spondylolysis or spondylolisthesis is the cause of low back pain, pars defects are frequently heralded by increased scintigraphic activity which is best detected and localized by SPECT.

  3. Positron emission tomography

    SciTech Connect

    Cohen, R.M.; Semple, W.E.; Gross, M.

    1986-03-01

    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.

  4. Theory of Mind and Schizophrenia: A Positron Emission Tomography Study of Medication-Free Patients

    PubMed Central

    Andreasen, Nancy C.; Calage, Chadi A.; O'Leary, Daniel S.

    2008-01-01

    Background: “Theory of mind” (TOM) refers to the ability to attribute mental states (ie, beliefs and goals) to one's self and others and to recognize that behaviors are guided by these mental states. This capacity, critical for social competence, is impaired in schizophrenia. We undertook a study of TOM in a group of patients with schizophrenia and healthy controls. Method: We used positron emission tomography to identify the neural circuits recruited during a verbal task that required participants to attribute mental states to a character in a story of their creation. The comparison task consisted of reading aloud a neutral story, controlling for the speech component of the task. Results: Patients and controls generated the same percentage of TOM utterances. However, the two groups had markedly different patterns of brain activation. Compared with controls, patients had a lower blood flow in multiple regions in the left hemisphere including the frontal and visual association cortices, posterior hippocampus, and insula. The flow was also lower in contralateral areas in the lateral cerebellum and vermis, thalamus, and posterior insula. On the other hand, the flow was higher in the patients predominantly in the right hemisphere, including multiple frontal and parietal regions, insula, visual association cortex, and pulvinar. Discussion: The areas of lower flow are consistent with previous studies indicating impairment in recruiting cortical-cerebellar circuitry in schizophrenia. The areas of higher flow may reflect a need to draw on the right hemisphere to compensate for deficits in left hemisphere networks that include frontal cortex, anterior cingulate, cerebellum, and thalamus. PMID:18559406

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

    PubMed Central

    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 controls [HC]). Untreated individuals with PTSD (N=25) with non-combat trauma histories, and TC (N=12) and HC (N=23) participated in a magnetic resonance (MR) imaging scan and a resting PET scan with the CB1 receptor antagonist radiotracer [11C]OMAR, which measures volume of distribution (VT) linearly related to CB1 receptor availability. Peripheral levels of anandamide, 2-arachidonoylglycerol (2-AG), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and cortisol were also assessed. In the PTSD group, relative to the HC and TC groups, we found elevated brain-wide [11C]OMAR VT values (F(2,53)=7.96, p=.001; 19.5% and 14.5% higher, respectively) which were most pronounced in women (F(1,53)=5.52, p=.023). Anandamide concentrations were reduced in the PTSD relative to the TC (53.1% lower) and HC (58.2% lower) groups. Cortisol levels were lower in the PTSD and TC groups relative to the HC group. Three biomarkers examined collectively—OMAR VT, anandamide, and cortisol—correctly classified nearly 85% of PTSD cases. These results suggest that abnormal CB1 receptor-mediated anandamide signaling is implicated in the etiology of PTSD, and provide a promising neurobiological model to develop novel, evidence-based pharmacotherapies for this disorder. PMID:23670490

  6. Emission Computed Tomography: A New Technique for the Quantitative Physiologic Study of Brain and Heart in Vivo

    DOE R&D Accomplishments Database

    Phelps, M. E.; Hoffman, E. J.; Huang, S. C.; Schelbert, H. R.; Kuhl, D. E.

    1978-01-01

    Emission computed tomography can provide a quantitative in vivo measurement of regional tissue radionuclide tracer concentrations. This facility when combined with physiologic models and radioactively labeled physiologic tracers that behave in a predictable manner allow measurement of a wide variety of physiologic variables. This integrated technique has been referred to as Physiologic Tomography (PT). PT requires labeled compounds which trace physiologic processes in a known and predictable manner, and physiologic models which are appropriately formulated and validated to derive physiologic variables from ECT data. In order to effectively achieve this goal, PT requires an ECT system that is capable of performing truly quantitative or analytical measurements of tissue tracer concentrations and which has been well characterized in terms of spatial resolution, sensitivity and signal to noise ratios in the tomographic image. This paper illustrates the capabilities of emission computed tomography and provides examples of physiologic tomography for the regional measurement of cerebral and myocardial metabolic rate for glucose, regional measurement of cerebral blood volume, gated cardiac blood pools and capillary perfusion in brain and heart. Studies on patients with stroke and myocardial ischemia are also presented.

  7. Glycine transporter type 1 occupancy by bitopertin: a positron emission tomography study in healthy volunteers.

    PubMed

    Martin-Facklam, Meret; Pizzagalli, Flavia; Zhou, Yun; Ostrowitzki, Susanne; Raymont, Vanessa; Brašić, James R; Parkar, Nikhat; Umbricht, Daniel; Dannals, Robert F; Goldwater, Ron; Wong, Dean F

    2013-02-01

    Deficient N-methyl-D-aspartate (NMDA) receptor transmission is thought to underlie schizophrenia. An approach for normalizing glutamate neurotransmission by enhancing NMDA receptor transmission is to increase glycine availability by inhibiting the glycine transporter type 1 (GlyT1). This study investigated the relationship between the plasma concentration of the glycine reuptake inhibitor bitopertin (RG1678) and brain GlyT1 occupancy. Healthy male volunteers received up to 175 mg bitopertin once daily, for 10-12 days. Three positron emission tomography scans, preceded by a single intravenous infusion of ∼30 mCi [(11)C]RO5013853, were performed: at baseline, on the last day of bitopertin treatment, and 2 days after drug discontinuation. Eighteen subjects were enrolled. At baseline, regional volume of distribution (V(T)) values were highest in the pons, thalamus, and cerebellum (1.7-2.7 ml/cm(3)) and lowest in cortical areas (∼0.8 ml/cm(3)). V(T) values were reduced to a homogeneous level following administration of 175 mg bitopertin. Occupancy values derived by a two-tissue five-parameter (2T5P) model, a simplified reference tissue model (SRTM), and a pseudoreference tissue model (PRTM) were overall comparable. At steady state, the relationship between bitopertin plasma concentration and GlyT1 occupancy derived by the 2T5P model, SRTM, and PRTM exhibited an EC(50) of ∼190, ∼200, and ∼130 ng/ml, respectively. E(max) was ∼92% independently of the model used. Bitopertin plasma concentration was a reliable predictor of occupancy because the concentration-occupancy relationship was superimposable at steady state and 2 days after drug discontinuation. These data allow understanding of the concentration-occupancy-efficacy relationship of bitopertin and support dose selection of future molecules. PMID:23132267

  8. Task-oriented quantitative image reconstruction in emission tomography for single- and multi-subject studies

    NASA Astrophysics Data System (ADS)

    Verhaeghe, Jeroen; Gravel, Paul; Reader, Andrew J.

    2010-12-01

    Task-based selection of image reconstruction methodology in emission tomography is a critically important step when designing a PET study. This paper concerns optimizing, given the measured data of the study only, reconstruction performance for a range of quantification tasks: finding the mean radioactivity concentration for different regions of interests (ROIs), different ROI sizes and different group sizes (i.e. the number of subjects in the PET study). At present, the variability of quantification performance of different reconstruction methods, according to both the ROI and group sizes, is largely ignored. In this paper, it is shown that both the ROI and group size have a tremendous impact on the error of the estimator for the task of ROI quantification. A study-specific, task-oriented and space-variant selection rule is proposed that selects a close to optimal estimate drawn from a series of estimates obtained by filtered backprojection (FBP) and different OSEM (ordered subset expectation maximization) iterations. The optimality criterion is to minimize an estimated mean square error (MSE), where the MSE is estimated from the data in the study using the bootstrap resampling technique. The proposed approach is appropriate for both pixel-level estimates and ROI estimates in single- and multi-subject studies. An extensive multi-trial simulation study using a 2D numerical phantom and relevant count levels shows that the proposed selection rule can produce quantitative estimates that are close to the estimates that minimize the true MSE (where the true MSE can only be obtained from many independent Monte-Carlo realizations with knowledge of the ground truth). This indicates that with the proposed selection rule one can obtain a close to optimal estimate while avoiding the critical step of selecting user-defined reconstruction settings (such as an OSEM iteration number or the choice between FBP and OSEM). In this initial 2D study, only FBP and OSEM reconstruction

  9. Single photon emission tomography in neurological studies: Instrumentation and clinical applications

    NASA Astrophysics Data System (ADS)

    Nikkinen, Paivi Helena

    One triple head and two single head gamma camera systems were used for single photon emission tomography (SPET) imaging of both patients and brain phantoms. Studies with an anatomical brain phantom were performed for evaluation of reconstruction and correction methods in brain perfusion SPET studies. The use of the triple head gamma camera system resulted in a significant increase in image contrast and resolution. This was mainly due to better imaging geometry and the use of a high resolution collimator. The conventional Chang attenuation correction was found suitable for the brain perfusion studies. In the brain perfusion studies region of interest (ROI) based semiquantitation methods were used. A ROI map based on anatomical areas was used in 70 elderly persons (age range 55-85 years) without neurological diseases and in patients suffering from encephalitis or having had a cardiac arrest. Semiquantitative reference values are presented. For the 14 patients with encephalitis the right-to-left side differences were calculated. Defect volume indexes were calculated for 64 patients with brain infarcts. For the 30 cardiac arrest patients the defect percentages and the anteroposterior ratios were used for semiquantitation. It is concluded that different semiquantitation methods are needed for the various patient groups. Age-related reference values will improve the interpretation of SPET data. For validation of the basal ganglia receptor studies measurements were performed using a cylindrical and an anatomical striatal phantom. In these measurements conventional and transmission imaging based non-uniform attenuation corrections were compared. A calibration curve was calculated for the determination of the specific receptor uptake ratio. In the phantom studies using the triple head camera the uptake ratio obtained from simultaneous transmission-emission protocol (STEP) acquisition and iterative reconstruction was closest to the true activity ratio. Conventional

  10. Multimodality imaging probe for positron emission tomography and fluorescence imaging studies.

    PubMed

    Pandey, Suresh K; Kaur, Jasmeet; Easwaramoorthy, Balu; Shah, Ankur; Coleman, Robert; Mukherjee, Jogeshwar

    2014-01-01

    Our goal is to develop multimodality imaging agents for use in cell tracking studies by positron emission tomography (PET) and optical imaging (OI). For this purpose, bovine serum albumin (BSA) was complexed with biotin (histologic studies), 5(6)-carboxyfluorescein, succinimidyl ester (FAM SE) (OI studies), and diethylenetriamine pentaacetic acid (DTPA) for chelating gallium 68 (PET studies). For synthesis of BSA-biotin-FAM-DTPA, BSA was coupled to (+)-biotin N-hydroxysuccinimide ester (biotin-NHSI). BSA-biotin was treated with DTPA-anhydride and biotin-BSA-DTPA was reacted with FAM. The biotin-BSA-DTPA-FAM was reacted with gallium chloride 3 to 5 mCi eluted from the generator using 0.1 N HCl and was passed through basic resin (AG 11 A8) and 150 μCi (100 μL, pH 7-8) was incubated with 0.1 mg of FAM conjugate (100 μL) at room temperature for 15 minutes to give 68Ga-BSA-biotin-DTPA-FAM. A shaved C57 black mouse was injected with FAM conjugate (50 μL) at one flank and FAM-68Ga (50 μL, 30 μCi) at the other. Immediately after injection, the mouse was placed in a fluorescence imaging system (Kodak In-Vivo F, Bruker Biospin Co., Woodbridge, CT) and imaged (λex: 465 nm, λem: 535 nm, time: 8 seconds, Xenon Light Source, Kodak). The same mouse was then placed under an Inveon microPET scanner (Siemens Medical Solutions, Knoxville, TN) injected (intravenously) with 25 μCi of 18F and after a half-hour (to allow sufficient bone uptake) was imaged for 30 minutes. Molecular weight determined using matrix-associated laser desorption ionization (MALDI) for the BSA sample was 66,485 Da and for biotin-BSA was 67,116 Da, indicating two biotin moieties per BSA molecule; for biotin-BSA-DTPA was 81,584 Da, indicating an average of 30 DTPA moieties per BSA molecule; and for FAM conjugate was 82,383 Da, indicating an average of 1.7 fluorescent moieties per BSA molecule. Fluorescence imaging clearly showed localization of FAM conjugate and FAM-68Ga at respective flanks of the mouse

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

    SciTech Connect

    Cameron, O.G.; Modell, J.G.; Hariharan, M. )

    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.

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

    PubMed

    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.

  13. Positron emission tomography wrist detector

    DOEpatents

    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.

  14. Single photon emission computed tomography

    SciTech Connect

    Piez, C.W. Jr.; Holman, B.L.

    1985-07-01

    Single photon emission computed tomography (SPECT) is becoming an increasingly important part of routine clinical nuclear medicine. By providing tomographic reconstructions in multiple planes through the patient, SPECT expands the clinical applications in nuclear medicine as well as providing better contrast, edge definition and separation of target from background activities. Imaging techniques have been developed for the evaluation of regional cerebral blood flow using radiolabeled amines. Thus, cerebral functional imaging can be used in the diagnosis of acute cerebral infarction, cerebral vascular disease, dementia and epilepsy. SPECT plays a complementary role in the evaluation of coronary artery disease, particularly when it is coupled with thallium-201 and exercise testing. SPECT extends our diagnostic capabilities in additional areas, such as liver and bone scintigraphy as well as tumor imaging with gallium-67.

  15. The potential of positron emission tomography for intratreatment dynamic lung tumor tracking: A phantom study

    SciTech Connect

    Yang, Jaewon; Yamamoto, Tokihiro; Mazin, Samuel R.; Graves, Edward E.; Keall, Paul J.

    2014-02-15

    Purpose: This study aims to evaluate the potential and feasibility of positron emission tomography for dynamic lung tumor tracking during radiation treatment. The authors propose a center of mass (CoM) tumor tracking algorithm using gated-PET images combined with a respiratory monitor and investigate the geometric accuracy of the proposed algorithm. Methods: The proposed PET dynamic lung tumor tracking algorithm estimated the target position information through the CoM of the segmented target volume on gated PET images reconstructed from accumulated coincidence events. The information was continuously updated throughout a scan based on the assumption that real-time processing was supported (actual processing time at each frame ≈10 s). External respiratory motion and list-mode PET data were acquired from a phantom programmed to move with measured respiratory traces (external respiratory motion and internal target motion) from human subjects, for which the ground truth target position was known as a function of time. The phantom was cylindrical with six hollow sphere targets (10, 13, 17, 22, 28, and 37 mm in diameter). The measured respiratory traces consisted of two sets: (1) 1D-measured motion from ten healthy volunteers and (2) 3D-measured motion from four lung cancer patients. The authors evaluated the geometric accuracy of the proposed algorithm by quantifying estimation errors (Euclidean distance) between the actual motion of targets (1D-motion and 3D-motion traces) and CoM trajectories estimated by the proposed algorithm as a function of time. Results: The time-averaged error of 1D-motion traces over all trajectories of all targets was 1.6 mm. The error trajectories decreased with time as coincidence events were accumulated. The overall error trajectory of 1D-motion traces converged to within 2 mm in approximately 90 s. As expected, more accurate results were obtained for larger targets. For example, for the 37 mm target, the average error over all 1D

  16. The potential of positron emission tomography for intratreatment dynamic lung tumor tracking: A phantom study

    PubMed Central

    Yang, Jaewon; Yamamoto, Tokihiro; Mazin, Samuel R.; Graves, Edward E.; Keall, Paul J.

    2014-01-01

    Purpose: This study aims to evaluate the potential and feasibility of positron emission tomography for dynamic lung tumor tracking during radiation treatment. The authors propose a center of mass (CoM) tumor tracking algorithm using gated-PET images combined with a respiratory monitor and investigate the geometric accuracy of the proposed algorithm. Methods: The proposed PET dynamic lung tumor tracking algorithm estimated the target position information through the CoM of the segmented target volume on gated PET images reconstructed from accumulated coincidence events. The information was continuously updated throughout a scan based on the assumption that real-time processing was supported (actual processing time at each frame ≈10 s). External respiratory motion and list-mode PET data were acquired from a phantom programmed to move with measured respiratory traces (external respiratory motion and internal target motion) from human subjects, for which the ground truth target position was known as a function of time. The phantom was cylindrical with six hollow sphere targets (10, 13, 17, 22, 28, and 37 mm in diameter). The measured respiratory traces consisted of two sets: (1) 1D-measured motion from ten healthy volunteers and (2) 3D-measured motion from four lung cancer patients. The authors evaluated the geometric accuracy of the proposed algorithm by quantifying estimation errors (Euclidean distance) between the actual motion of targets (1D-motion and 3D-motion traces) and CoM trajectories estimated by the proposed algorithm as a function of time. Results: The time-averaged error of 1D-motion traces over all trajectories of all targets was 1.6 mm. The error trajectories decreased with time as coincidence events were accumulated. The overall error trajectory of 1D-motion traces converged to within 2 mm in approximately 90 s. As expected, more accurate results were obtained for larger targets. For example, for the 37 mm target, the average error over all 1D

  17. Modelling Random Coincidences in Positron Emission Tomography by Using Singles and Prompts: A Comparison Study.

    PubMed

    Oliver, Josep F; Rafecas, M

    2016-01-01

    Random coincidences degrade the image in Positron Emission Tomography, PET. To compensate for their degradation effects, the rate of random coincidences should be estimated. Under certain circumstances, current estimation methods fail to provide accurate results. We propose a novel method, "Singles-Prompts" (SP), that includes the information conveyed by prompt coincidences and models the pile-up. The SP method has the same structure than the well-known "Singles Rate" (SR) approach. Hence, SP can straightforwardly replace SR. In this work, the SP method has been extensively assessed and compared to two conventional methods, SR and the delayed window (DW) method, in a preclinical PET scenario using Monte-Carlo simulations. SP offers accurate estimates for the randoms rates, while SR and DW tend to overestimate the rates (∼10%, and 5%, respectively). With pile-up, the SP method is more robust than SR (but less than DW). At the image level, the contrast is overestimated in SR-corrected images, +16%, while SP produces the correct value. Spill-over is slightly reduced using SP instead of SR. The DW images values are similar to those of SP except for low-statistic scenarios, where DW behaves as if randoms were not compensated for. In particular, the contrast is reduced, -16%. In general, the better estimations of SP translate into better image quality. PMID:27603143

  18. Modelling Random Coincidences in Positron Emission Tomography by Using Singles and Prompts: A Comparison Study

    PubMed Central

    2016-01-01

    Random coincidences degrade the image in Positron Emission Tomography, PET. To compensate for their degradation effects, the rate of random coincidences should be estimated. Under certain circumstances, current estimation methods fail to provide accurate results. We propose a novel method, “Singles–Prompts” (SP), that includes the information conveyed by prompt coincidences and models the pile–up. The SP method has the same structure than the well-known “Singles Rate” (SR) approach. Hence, SP can straightforwardly replace SR. In this work, the SP method has been extensively assessed and compared to two conventional methods, SR and the delayed window (DW) method, in a preclinical PET scenario using Monte–Carlo simulations. SP offers accurate estimates for the randoms rates, while SR and DW tend to overestimate the rates (∼10%, and 5%, respectively). With pile-up, the SP method is more robust than SR (but less than DW). At the image level, the contrast is overestimated in SR-corrected images, +16%, while SP produces the correct value. Spill–over is slightly reduced using SP instead of SR. The DW images values are similar to those of SP except for low-statistic scenarios, where DW behaves as if randoms were not compensated for. In particular, the contrast is reduced, −16%. In general, the better estimations of SP translate into better image quality. PMID:27603143

  19. Neural correlates of malingering in mild traumatic brain injury: A positron emission tomography study.

    PubMed

    Spadoni, Andrea D; Kosheleva, Elena; Buchsbaum, Monte S; Simmons, Alan N

    2015-09-30

    The detection of malingering in cognitive performance is a challenge in clinical and legal environments. Neuroimaging may provide an objective method to determine the source of failure on tests of symptom validity. Participants comprised 45 combat veterans, 31 with mild traumatic brain injury (mTBI), not seeking medical or legal compensation, who completed the Tombaugh Test of Memory Malingering (TOMM) and a positron emission tomography (PET) scan. Based on TOMM performance (i.e., less than 45 of 50 total correct, suggesting suboptimal effort or malingering), subjects were separated into poor TOMM score (PT; n=10) and good TOMM score (GT; n=35) groups. Voxel-based multiple regression analysis with Group (GT/PT) predicting uptake of fluorodeoxyglucose revealed decreased brain metabolism in the ventromedial prefrontal cortex of poor performers. The current findings may suggest that poor TOMM performance in those with combat trauma and mTBI may be related to ventromedial prefrontal cortical dysfunction. These findings have important implications for the disentanglement of feigned versus actual memory impairment, where the latter may be secondary to neural mechanisms not consistent with forgetting or deception.

  20. The metabolic landscape of cortico-basal ganglionic degeneration: regional asymmetries studied with positron emission tomography.

    PubMed Central

    Eidelberg, D; Dhawan, V; Moeller, J R; Sidtis, J J; Ginos, J Z; Strother, S C; Cederbaum, J; Greene, P; Fahn, S; Powers, J M

    1991-01-01

    Regional metabolic rate for glucose (rCMRGlc) was estimated using [18F]fluorodeoxyglucose (FDG) and positron emission tomography (PET) in five patients (four men, one woman; mean age 68; mean disease duration 2.4 years) with clinical findings consistent with the syndrome of cortico-basal ganglionic degeneration (CBGD). Left-right rCMRGlc asymmetry, (L-R)/(L + R) x 100, was calculated for 13 grey matter regions and compared with regional metabolic data from 18 normal volunteers and nine patients with asymmetrical Parkinson's disease (PD). In the CBGD group mean metabolic asymmetry values in the thalamus, inferior parietal lobule and hippocampus were greater than those measured in normal control subjects and patients with asymmetrical PD (p less than 0.02). Parietal lobe asymmetry of 5% or more was evident in all CBGD patients, whereas in PD patients and normal controls, all regional asymmetry measures were less than 5% in absolute value. Measures of frontal, parietal and hemispheric metabolic asymmetry were found to be positively correlated with asymmetries in thalamic rCMRGlc (p less than 0.05). The presence of cortico-thalamic metabolic asymmetry is consistent with the focal neuropathological changes reported in CBGD brains. Our findings suggest that metabolic asymmetries detected with FDG/PET may support a diagnosis of CBGD in life. Images PMID:1744638

  1. A behavioral and micro positron emission tomography imaging study in a rat model of hypothyroidism.

    PubMed

    Yu, Jing; Tang, Yi-Yuang; Feng, Hong-Bo; Cheng, Xiao-Xin

    2014-09-01

    Hypothyroidism leads to somatic, neuropsychological, and psychiatric changes that are similar to depression. The mechanisms underlying the behavioral abnormalities in adult onset hypothyroidism remain ambiguous. Hypothyroidism was induced in adult male Wistar rats by the maintenance of 0.05% propylthiouracil (PTU) in drinking water for 5 weeks (hypothyroid group; HP group); control rats (CON group) received an equivalent amount of water. The open field and sucrose preference tests were employed, and the link between behavioral changes and brain glucose metabolism was evaluated using micro positron emission tomography imaging. The open field test revealed slightly decreased locomotor activity and significantly reduced rearing and defecation in the hypothyroid group. Hypothyroid rats were also characterized by decreased body weight, sucrose preference, and relative sucrose intake compared to control rats. Hypothyroidism induced reduced brain glucose metabolism in the bilateral motor cortex, the caudate putamen, the cortex cingulate, the nucleus accumbens, and the frontal association cortex. A decreased sucrose preference was positively correlated with metabolic glucose changes in the caudate putamen and the nucleus accumbens. The results indicate that the activity pattern in adult onset hypothyroidism is different from the activity pattern when hypothyroidism is induced in the developmental period of the central nervous system. Decreased sucrose preference in hypothyroid rats may be attributed to anhedonia. Furthermore, these findings suggest there may be a common mechanism underlying adult onset hypothyroidism and depression.

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

    SciTech Connect

    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.

  3. A Study on Determination of an Optimized Detector for Single Photon Emission Computed Tomography.

    PubMed

    Khoshakhlagh, Mohammad; Islamian, Jalil Pirayesh; Abedi, Mohammad; Mahmoudian, Babak; Mardanshahi, Ali Reza

    2016-01-01

    The detector is a critical component of the single photon emission computed tomography (SPECT) imaging system for giving accurate information from the exact pattern of radionuclide distribution in the target organ. The SIMIND Monte Carlo program was utilized for the simulation of a Siemen's dual head variable angle SPECT imaging system with a low energy high resolution (LEHR) collimator. The Planar and SPECT scans for a (99m)Tc point source and a Jaszczak Phantom with the both experiment and simulated systems were prepared and after verification and validation of the simulated system, the similar scans of the phantoms were compared (from the point of view of the images' quality), namely, the simulated system with the detectors including bismuth germanate (BGO), yttrium aluminum garnet (YAG:Ce), Cerium-doped yttrium aluminum garnet (YAG:Ce), yttrium aluminum perovslite (YAP:Ce), lutetium aluminum garnet (LuAG:Ce), cerium activated lanthanum bromide (LaBr3), cadmium zinc telluride (CZT), and sodium iodide activated with thallium [NaI(Tl)]. The parameters of full width at half maximum (FWHM), energy and special resolution, sensitivity, and also the comparison of images' quality by the structural similarity (SSIM) algorithm with the Zhou Wang and Rouse/Hemami methods were analyzed. FWHMs for the crystals were calculated at 13.895, 14.321, 14.310, 14.322, 14.184, and 14.312 keV and the related energy resolutions obtained 9.854, 10.229, 10.221, 10.230, 10.131, and 10.223 %, respectively. Finally, SSIM indexes for comparison of the phantom images were calculated at 0.22172, 0.16326, 0.18135, 0.17301, 0.18412, and 0.20433 as compared to NaI(Tl). The results showed that BGO and LuAG: Ce crystals have high sensitivity and resolution, and better image quality as compared to other scintillation crystals. PMID:26912973

  4. A Study on Determination of an Optimized Detector for Single Photon Emission Computed Tomography

    PubMed Central

    Khoshakhlagh, Mohammad; Islamian, Jalil Pirayesh; Abedi, Mohammad; Mahmoudian, Babak; Mardanshahi, Ali Reza

    2016-01-01

    The detector is a critical component of the single photon emission computed tomography (SPECT) imaging system for giving accurate information from the exact pattern of radionuclide distribution in the target organ. The SIMIND Monte Carlo program was utilized for the simulation of a Siemen's dual head variable angle SPECT imaging system with a low energy high resolution (LEHR) collimator. The Planar and SPECT scans for a 99mTc point source and a Jaszczak Phantom with the both experiment and simulated systems were prepared and after verification and validation of the simulated system, the similar scans of the phantoms were compared (from the point of view of the images’ quality), namely, the simulated system with the detectors including bismuth germanate (BGO), yttrium aluminum garnet (YAG:Ce), Cerium-doped yttrium aluminum garnet (YAG:Ce), yttrium aluminum perovslite (YAP:Ce), lutetium aluminum garnet (LuAG:Ce), cerium activated lanthanum bromide (LaBr3), cadmium zinc telluride (CZT), and sodium iodide activated with thallium [NaI(Tl)]. The parameters of full width at half maximum (FWHM), energy and special resolution, sensitivity, and also the comparison of images’ quality by the structural similarity (SSIM) algorithm with the Zhou Wang and Rouse/Hemami methods were analyzed. FWHMs for the crystals were calculated at 13.895, 14.321, 14.310, 14.322, 14.184, and 14.312 keV and the related energy resolutions obtained 9.854, 10.229, 10.221, 10.230, 10.131, and 10.223 %, respectively. Finally, SSIM indexes for comparison of the phantom images were calculated at 0.22172, 0.16326, 0.18135, 0.17301, 0.18412, and 0.20433 as compared to NaI(Tl). The results showed that BGO and LuAG: Ce crystals have high sensitivity and resolution, and better image quality as compared to other scintillation crystals. PMID:26912973

  5. The Role of Chemistry in Positron Emission Tomography.

    ERIC Educational Resources Information Center

    Feliu, Anthony L.

    1988-01-01

    Investigates use of positron emission tomography (PET) to study in-vivo metabolic processes. Discusses methodology of PET and medical uses. Outlines the production of different radioisotopes used in PET radiotracers. Includes selected bibliography. (ML)

  6. Single Photon Emission Computed Tomography (SPECT)

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Single Photon Emission Computed Tomography (SPECT) Updated:Sep 11,2015 ... Persantine) or dobutamine. The tests may take between 2 and 2 1/2 hours. What happens after ...

  7. Scintillators for positron emission tomography

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.

    1995-09-01

    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 ({le} 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 {le} 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so {le}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.

  8. 18Fluorodeoxyglucose positron emission tomography studies in presumed Alzheimer cases, including 13 serial scans.

    PubMed

    McGeer, E G; Peppard, R P; McGeer, P L; Tuokko, H; Crockett, D; Parks, R; Akiyama, H; Calne, D B; Beattie, B L; Harrop, R

    1990-02-01

    Positron emission tomographic (PET) data on local cerebral metabolic rates for glucose (LCMR) are reported for 32 regions of interest (ROI)s in cross-sectional studies on 57 patients with clinically diagnosed Alzheimer's disease (AD) and 20 neurologically normal controls, and in serial studies on 13 of the AD cases, including a familial, young-onset case where the diagnosis has been confirmed at autopsy. Extensive psychological testing was done on all the AD cases. Almost all cortical regions showed a significant decline in LCMR with age in the control subjects. There were the expected cortical metabolic deficits in AD and the serial studies showed a general increase in such deficits over time in 12 of the 13 cases. The regions showing the greatest declines with time in serial studies are the same as those showing the most severe deficiencies in cross-sectional studies. The young-onset case did not show a greater rate of metabolic decline than many of the older cases studied. Results on individual psychological tests tended to correlate with metabolic rates in multiple, rather than single, cortical regions, suggesting intact neuronal networks are required for good performance. The correlations with cortical metabolic activity found were of a sign indicating that the higher the metabolic rates and the better the left:right asymmetry index, the better was the performance.

  9. Fan Beam Emission Tomography for Laminar Fires

    NASA Technical Reports Server (NTRS)

    Sivathanu, Yudaya; Lim, Jongmook; Feikema, Douglas

    2003-01-01

    Obtaining information on the instantaneous structure of turbulent and transient flames is important in a wide variety of applications such as fire safety, pollution reduction, flame spread studies, and model validation. Durao et al. has reviewed the different methods of obtaining structure information in reacting flows. These include Tunable Laser Absorption Spectroscopy, Fourier Transform Infrared Spectroscopy, and Emission Spectroscopy to mention a few. Most flames emit significant radiation signatures that are used in various applications such as fire detection, light-off detection, flame diagnostics, etc. Radiation signatures can be utilized to maximum advantage for determining structural information in turbulent flows. Emission spectroscopy is most advantageous in the infrared regions of the spectra, principally because these emission lines arise from transitions in the fundamental bands of stable species such as CO2 and H2O. Based on the above, the objective of this work was to develop a fan beam emission tomography system to obtain the local scalar properties such as temperature and mole fractions of major gas species from path integrated multi-wavelength infrared radiation measurements.

  10. Data analysis in emission tomography using emission-count posteriors

    NASA Astrophysics Data System (ADS)

    Sitek, Arkadiusz

    2012-11-01

    A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography.

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

    SciTech Connect

    Kuhl, D.E.

    1992-07-01

    The general goals of the physics and kinetic modeling projects are to: (1) improve the quantitative information extractable from PET images, and (2) develop, implement and optimize tracer kinetic models for new PET neurotransmitter/receptor ligands aided by computer simulations. Work towards improving PET quantification has included projects evaluating: (1) iterative reconstruction algorithms using supplemental boundary information, (2) automated registration of dynamic PET emission and transmission data using sinogram edge detection, and (3) automated registration of multiple subjects to a common coordinate system, including the use of non-linear warping methods. Simulation routines have been developed providing more accurate representation of data generated from neurotransmitter/receptor studies. Routines consider data generated from complex compartmental models, high or low specific activity administrations, non-specific binding, pre- or post-injection of cold or competing ligands, temporal resolution of the data, and radiolabeled metabolites. Computer simulations and human PET studies have been performed to optimize kinetic models for four new neurotransmitter/receptor ligands, [{sup 11}C]TRB (muscarinic), [{sup 11}C]flumazenil (benzodiazepine), [{sup 18}F]GBR12909, (dopamine), and [{sup 11}C]NMPB (muscarinic).

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

    SciTech Connect

    Kuhl, D.E.

    1992-01-01

    The general goals of the physics and kinetic modeling projects are to: (1) improve the quantitative information extractable from PET images, and (2) develop, implement and optimize tracer kinetic models for new PET neurotransmitter/receptor ligands aided by computer simulations. Work towards improving PET quantification has included projects evaluating: (1) iterative reconstruction algorithms using supplemental boundary information, (2) automated registration of dynamic PET emission and transmission data using sinogram edge detection, and (3) automated registration of multiple subjects to a common coordinate system, including the use of non-linear warping methods. Simulation routines have been developed providing more accurate representation of data generated from neurotransmitter/receptor studies. Routines consider data generated from complex compartmental models, high or low specific activity administrations, non-specific binding, pre- or post-injection of cold or competing ligands, temporal resolution of the data, and radiolabeled metabolites. Computer simulations and human PET studies have been performed to optimize kinetic models for four new neurotransmitter/receptor ligands, ({sup 11}C)TRB (muscarinic), ({sup 11}C)flumazenil (benzodiazepine), ({sup 18}F)GBR12909, (dopamine), and ({sup 11}C)NMPB (muscarinic).

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

    PubMed Central

    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

  14. Tumor characteristics of ductal carcinoma in situ of breast visualized on [F-18] fluorodeoxyglucose-positron emission tomography/computed tomography: Results from a retrospective study

    PubMed Central

    Fujioka, Tomoyuki; Kubota, Kazunori; Toriihara, Akira; Machida, Youichi; Okazawa, Kaori; Nakagawa, Tsuyoshi; Saida, Yukihisa; Tateishi, Ukihide

    2016-01-01

    AIM To clarify clinicopathological features of ductal carcinoma in situ (DCIS) visualized on [F-18] fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT). METHODS This study retrospectively reviewed 52 consecutive tumors in 50 patients with pathologically proven pure DCIS who underwent [F-18] FDG-PET/CT before surgery. [F-18] FDG-PET/CT was performed after biopsy in all patients. The mean interval from biopsy to [F-18] FDG-PET/CT was 29.2 d. [F-18] FDG uptake by visual analysis and maximum standardized uptake value (SUVmax) was compared with clinicopathological characteristics. RESULTS [F-18] FDG uptake was visualized in 28 lesions (53.8%) and the mean and standard deviation of SUVmax was 1.63 and 0.90. On univariate analysis, visual analysis and the SUVmax were associated with symptomatic presentation (P = 0.012 and 0.002, respectively), palpability (P = 0.030 and 0.024, respectively), use of core-needle biopsy (CNB) (P = 0.023 and 0.012, respectively), ultrasound-guided biopsy (P = 0.040 and 0.006, respectively), enhancing lesion ≥ 20 mm on magnetic resonance imaging (MRI) (P = 0.001 and 0.010, respectively), tumor size ≥ 20 mm on histopathology (P = 0.002 and 0.008, respectively). However, [F-18] FDG uptake parameters were not significantly associated with age, presence of calcification on mammography, mass formation on MRI, presence of comedo necrosis, hormone status (estrogen receptor, progesterone receptor and human epidermal growth factor receptor-2), and nuclear grade. The factors significantly associated with visual analysis and SUVmax were symptomatic presentation (P = 0.019 and 0.001, respectively), use of CNB (P = 0.001 and 0.031, respectively), and enhancing lesion ≥ 20 mm on MRI (P = 0.001 and 0.049, respectively) on multivariate analysis. CONCLUSION Although DCIS of breast is generally non-avid tumor, symptomatic and large tumors (≥ 20 mm) tend to be visualized on [F-18] FDG-PET/CT. PMID:27648168

  15. Positron Emission Tomography of the Heart

    DOE R&D Accomplishments Database

    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.

  16. Methodological aspects of brain activation studies: cerebral blood flow determined with [15O]butanol and positron emission tomography.

    PubMed

    Ingvar, M; Eriksson, L; Greitz, T; Stone-Elander, S; Dahlbom, M; Rosenqvist, G; af Trampe, P; von Euler, C

    1994-07-01

    In this methodological study, a procedure for measuring regional CBF (rCBF) with positron emission tomography and 15O-labelled tracers is optimized. Four healthy volunteers were subjected to eight studies with use of [15O]butanol as a tracer: four times while reading aloud and four times while reading silently from a phonologically balanced list of single words. The gain from these repeated intra-individual studies of the same activation state (fractionation) was demonstrated in terms of noise-equivalent counts in a phantom study. A computerized brain atlas was used to reformat the images to a common anatomical representation, thereby minimizing the effects of inter- and intra-individual anatomical and positional variations. This allowed the formation of inter- and intra-individual average subtraction images with error estimates. Differences between the two activation states were detected with use of an exploratory significance map based on a paired Student's t test. The results compared well with Friston's method of determining levels of statistical significance. No difference was obtained when comparing results from rCBF images and images generated from measurement of uptake of the tracer. The paradigm chosen for activation was shown to yield a constant activation level during the repeated measurements (i.e., no habituation).

  17. Advanced Instrumentation for Positron Emission Tomography [PET

    DOE R&D Accomplishments Database

    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.

  18. A positron emission tomography study of nigro-striatal dopaminergic mechanisms underlying attention: implications for ADHD and its treatment.

    PubMed

    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; Sahakian, Barbara J; Müller, Ulrich

    2013-11-01

    Through the combined use of (18)F-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 scanned and tested on a computerized sustained attention task after oral methylphenidate (0.5 mg/kg) and placebo administration in a within-subject, double-blind, cross-over design. Although patients with attention deficit/hyperactivity disorder as a group showed significant attentional deficits and reduced grey matter volume in fronto-striato-cerebellar and limbic networks, they had equivalent D2/D3 receptor availability and equivalent increases in endogenous dopamine after methylphenidate treatment to that observed in healthy control subjects. However, poor attentional performers drawn from both the attention deficit/hyperactivity disorder and the control groups had significantly reduced left caudate dopamine activity. Methylphenidate significantly increased dopamine levels in all nigro-striatal regions, thereby normalizing dopamine levels in the left caudate in low performers. Behaviourally, methylphenidate improved sustained attention in a baseline performance-dependent manner, irrespective of diagnosis. This finding was accompanied by an equally performance-dependent effect of the drug on dopamine release in the midbrain, whereby low performers showed reduced dopamine release in this region. Collectively, these findings support a dimensional model of attentional deficits and underlying nigro-striatal dopaminergic mechanisms of attention deficit/hyperactivity disorder that extends into the healthy population. Moreover, they confer midbrain dopamine autoreceptors a hitherto

  19. A positron emission tomography study of the neural basis of informational and energetic masking effects in speech perception.

    PubMed

    Scott, Sophie K; Rosen, Stuart; Wickham, Lindsay; Wise, Richard J S

    2004-02-01

    Positron emission tomography (PET) was used to investigate the neural basis of the comprehension of speech in unmodulated noise ("energetic" masking, dominated by effects at the auditory periphery), and when presented with another speaker ("informational" masking, dominated by more central effects). Each type of signal was presented at four different signal-to-noise ratios (SNRs) (+3, 0, -3, -6 dB for the speech-in-speech, +6, +3, 0, -3 dB for the speech-in-noise), with listeners instructed to listen for meaning to the target speaker. Consistent with behavioral studies, there was SNR-dependent activation associated with the comprehension of speech in noise, with no SNR-dependent activity for the comprehension of speech-in-speech (at low or negative SNRs). There was, in addition, activation in bilateral superior temporal gyri which was associated with the informational masking condition. The extent to which this activation of classical "speech" areas of the temporal lobes might delineate the neural basis of the informational masking is considered, as is the relationship of these findings to the interfering effects of unattended speech and sound on more explicit working memory tasks. This study is a novel demonstration of candidate neural systems involved in the perception of speech in noisy environments, and of the processing of multiple speakers in the dorso-lateral temporal lobes. PMID:15000192

  20. A positron emission tomography study of the neural basis of informational and energetic masking effects in speech perception

    NASA Astrophysics Data System (ADS)

    Scott, Sophie K.; Rosen, Stuart; Wickham, Lindsay; Wise, Richard J. S.

    2004-02-01

    Positron emission tomography (PET) was used to investigate the neural basis of the comprehension of speech in unmodulated noise (``energetic'' masking, dominated by effects at the auditory periphery), and when presented with another speaker (``informational'' masking, dominated by more central effects). Each type of signal was presented at four different signal-to-noise ratios (SNRs) (+3, 0, -3, -6 dB for the speech-in-speech, +6, +3, 0, -3 dB for the speech-in-noise), with listeners instructed to listen for meaning to the target speaker. Consistent with behavioral studies, there was SNR-dependent activation associated with the comprehension of speech in noise, with no SNR-dependent activity for the comprehension of speech-in-speech (at low or negative SNRs). There was, in addition, activation in bilateral superior temporal gyri which was associated with the informational masking condition. The extent to which this activation of classical ``speech'' areas of the temporal lobes might delineate the neural basis of the informational masking is considered, as is the relationship of these findings to the interfering effects of unattended speech and sound on more explicit working memory tasks. This study is a novel demonstration of candidate neural systems involved in the perception of speech in noisy environments, and of the processing of multiple speakers in the dorso-lateral temporal lobes.

  1. Effect of aspartame-derived phenylalanine on neutral amino acid uptake in human brain: a positron emission tomography study.

    PubMed

    Koeppe, R A; Shulkin, B L; Rosenspire, K C; Shaw, L A; Betz, A L; Mangner, T; Price, J C; Agranoff, B W

    1991-05-01

    The possible effects of elevation of the plasma phenylalanine level secondary to the ingestion of aspartame on brain amino acid uptake in human subjects have been investigated by means of positron emission tomography (PET). 1-[11C]Aminocyclohexanecarboxylate [( 11C]ACHC) is a poorly metabolized synthetic amino acid that crosses the blood-brain barrier by the same carrier that transports naturally occurring large neutral amino acids. Quantitative test-retest PET studies were performed on 15 individuals. Seven received two identical baseline scans, whereas eight received a baseline scan followed by a scan performed approximately 40-45 min following ingestion of an orange-flavored beverage containing 34 mg/kg of body weight of the low-calorie sweetener aspartame, a dose equivalent to the amount in 5 L of diet soft drink consumed all at once by the study subjects, weighing an average of 76 kg. The 40-45-min interval was selected to maximize the detection of possible decreases in ACHC uptake resulting from increased competition for the carrier, because the plasma phenylalanine level is known to peak at this time. We observed an 11.5% decrease in the amino acid transport rate constant K1 and a smaller decrease in the tissue distribution volume of ACHC (6%). Under conditions of normal dietary use, aspartame is thus unlikely to cause changes in brain amino acid uptake that are measurable by PET.

  2. Choice of reference area in studies of Alzheimer's disease using positron emission tomography with fluorodeoxyglucose-F18.

    PubMed

    Yakushev, Igor; Landvogt, Christian; Buchholz, Hans-Georg; Fellgiebel, Andreas; Hammers, Alexander; Scheurich, Armin; Schmidtmann, Irene; Gerhard, Alexander; Schreckenberger, Mathias; Bartenstein, Peter

    2008-11-30

    At present, there is still no consensus on the choice of the reference area in positron emission tomography (PET) studies of Alzheimer's disease (AD). In this study, PET scans with fluorodeoxyglucose-F18 were carried out in the following groups of subjects: 47 patients with probable AD, 8 patients with mild cognitive impairment, and 15 age-similar healthy subjects. Scans normalized to the cerebral global mean (CGM), cerebellum (CBL), and the primary sensorimotor cortex (SMC). We evaluated the effect of the different count normalization procedures on the accuracy of (18)F-FDG PET to detect AD-specific metabolic abnormalities (voxel-based group comparison) and to differentiate between patients and healthy subjects (ROI-based discriminant analysis) with regard to the degree of clinical deterioration. Metabolic reductions in groups of very mildly, mildly and moderate-to-severely affected patients appeared, respectively, 2.2, 2.6, and 2.7 times greater in spatial extent when tracer uptake was normalized to SMC rather than to CGM. The overall accuracy of discrimination was 94%, 91%, and 80% after normalization to SMC, CBL, and CGM, respectively. In general, normalization to SMC was somewhat superior to cerebellar normalization, allowing the detection of more pronounced metabolic deficits and the more accurate discrimination of patients from non-patients. Normalization to CGM should be used with great caution not only in advanced stages of dementia, but also in very mild AD cases. PMID:18930634

  3. Kinetics of in vivo binding of antagonist to muscarinic cholinergic receptor in the human heart studied by Positron Emission Tomography

    SciTech Connect

    Syrota, A.; Paillotin, G.; Davy, J.M.; Aumont, M.C.

    1984-08-27

    Positron Emission Tomography (PET) was used to analyze in vivo antagonist binding to human myocardial muscarinic cholinergic receptor. The methiodide salt of the muscarinic antagonist, quinuclidinyl benzilate (MQNB), was labeled with the positron emitter, Carbon-11, and injected intravenously to 8 normal subjects. /sup 11/C-MQNB concentration was determined in vivo in the ventricular septum from 40 cross-sectional images acquired at the same transverse level over a period of 70 minutes. In 4 subjects, various amounts of unlabeled atropine were rapidly injected at 20 minutes to study whether atropine competitively inhibited MQNB. The kinetics of binding of /sup 11/C-MQNB were not the same in vivo and in vitro. The apparent dissociation rate of /sup 11/C-MQNB in vivo was much slower (by 1 to 2 orders of magnitude) than that observed in vitro with /sup 3/H-QNB. After atropine injection, /sup 11/C-MQNB dissociated from its binding sites at a rate that apparently depended on the amount of atropine present. /sup 11/C-MQNB kinetics were analyzed with a mathematical model which assumes the existence of a boundary layer containing free ligand in the vicinity of the binding sites. The dissociation rate of the radioligand depends on the probability of its rebinding to a free receptor site. 11 references, 1 table.

  4. The association between heroin expenditure and dopamine transporter availability--a single-photon emission computed tomography study.

    PubMed

    Lin, Shih-Hsien; Chen, Kao Chin; Lee, Sheng-Yu; Chiu, Nan Tsing; Lee, I Hui; Chen, Po See; Yeh, Tzung Lieh; Lu, Ru-Band; Chen, Chia-Chieh; Liao, Mei-Hsiu; Yang, Yen Kuang

    2015-03-30

    One of the consequences of heroin dependency is a huge expenditure on drugs. This underlying economic expense may be a grave burden for heroin users and may lead to criminal behavior, which is a huge cost to society. The neuropsychological mechanism related to heroin purchase remains unclear. Based on recent findings and the established dopamine hypothesis of addiction, we speculated that expenditure on heroin and central dopamine activity may be associated. A total of 21 heroin users were enrolled in this study. The annual expenditure on heroin was assessed, and the availability of the dopamine transporter (DAT) was assessed by single-photon emission computed tomography (SPECT) using [(99m)TC]TRODAT-1. Parametric and nonparametric correlation analyses indicated that annual expenditure on heroin was significantly and negatively correlated with the availability of striatal DAT. After adjustment for potential confounders, the predictive power of DAT availability was significant. Striatal dopamine function may be associated with opioid purchasing behavior among heroin users, and the cycle of spiraling dysfunction in the dopamine reward system could play a role in this association.

  5. Diagnosis of dementia with single photon emission computed tomography

    SciTech Connect

    Jagust, W.J.; Budinger, T.F.; Reed, B.R.

    1987-03-01

    Single photon emission computed tomography is a practical modality for the study of physiologic cerebral activity in vivo. We utilized single photon emission computed tomography and N-isopropyl-p-iodoamphetamine iodine 123 to evaluate regional cerebral blood flow in nine patients with Alzheimer's disease (AD), five healthy elderly control subjects, and two patients with multi-infarct dementia. We found that all subjects with AD demonstrated flow deficits in temporoparietal cortex bilaterally, and that the ratio of activity in bilateral temporoparietal cortex to activity in the whole slice allowed the differentiation of all patients with AD from both the controls and from the patients with multi-infarct dementia. Furthermore, this ratio showed a strong correlation with disease severity in the AD group. Single photon emission computed tomography appears to be useful in the differential diagnosis of dementia and reflects clinical features of the disease.

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

    PubMed

    Dannals, R F; Långström, B; Ravert, H T; Wilson, A A; Wagner, H N

    1988-01-01

    Dexetimide (Fig. 1a), a potent muscarinic cholinergic receptor antagonist, and levetimide (Fig. 1b), its pharmacologically inactive enantiomer, were labeled with 11C for non-invasive in vivo studies of muscarinic cholinergic receptors in the human brain using positron emission tomography. The syntheses were completed in approximately 32 min using [alpha-11C]benzyl iodide as the precursor. The synthesis, purification, characterization and determination of specific activity are presented and discussed. PMID:2838435

  7. Positron emission tomography tracers for imaging angiogenesis

    PubMed Central

    Beer, Ambros J.; Wang, Hui; Chen, Xiaoyuan

    2013-01-01

    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. PMID:20559632

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

    SciTech Connect

    Kuhl, D.E.

    1993-01-01

    This progress report describes accomplishments of four programs. The four programs are entitled (1) Faster,simpler processing of positron-computing precursors: New physicochemical approaches, (2) Novel solid phase reagents and methods to improve radiosynthesis and isotope production, (3) Quantitative evaluation of the extraction of information from PET images, and (4) Optimization of tracer kinetic methods for radioligand studies in PET.

  9. Sensitivity analysis for liver iron measurement through neutron stimulated emission computed tomography: a Monte Carlo study in GEANT4.

    PubMed

    Agasthya, G A; Harrawood, B C; Shah, J P; Kapadia, A J

    2012-01-01

    Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive imaging modality to detect and quantify iron overload in the human liver. NSECT uses gamma photons emitted by the inelastic interaction between monochromatic fast neutrons and iron nuclei in the body to detect and quantify the disease. Previous simulated and physical experiments with phantoms have shown that NSECT has the potential to accurately diagnose iron overload with reasonable levels of radiation dose. In this work, we describe the results of a simulation study conducted to determine the sensitivity of the NSECT system for hepatic iron quantification in patients of different sizes. A GEANT4 simulation of the NSECT system was developed with a human liver and two torso sizes corresponding to small and large patients. The iron concentration in the liver ranged between 0.5 and 20 mg g(-1), corresponding to clinically reported iron levels in iron-overloaded patients. High-purity germanium gamma detectors were simulated to detect the emitted gamma spectra, which were background corrected using suitable water phantoms and analyzed to determine the minimum detectable level (MDL) of iron and the sensitivity of the NSECT system. These analyses indicate that for a small patient (torso major axis = 30 cm) the MDL is 0.5 mg g(-1) and sensitivity is ∼13 ± 2 Fe counts/mg/mSv and for a large patient (torso major axis = 40 cm) the values are 1 mg g(-1) and ∼5 ± 1 Fe counts/mg/mSv, respectively. The results demonstrate that the MDL for both patient sizes lies within the clinically significant range for human iron overload.

  10. Serotonin 2A Receptors in Obsessive-Compulsive Disorder: a Positron Emission Tomography Study with [11C]MDL 100907

    PubMed Central

    Simpson, H. Blair; Slifstein, Mark; Bender, James; Xu, Xiaoyan; Hackett, Elizabeth; Maher, Michael J.; Abi-Dargham, Anissa

    2014-01-01

    Background Serotonergic abnormalities are hypothesized to contribute to obsessive-compulsive disorder (OCD). This study used positron emission tomography (PET) with the radioligand [11C]MDL 100907 to examine whether the distribution of one of the serotonin receptors, the 5-HT2A receptor, is altered in OCD. Methods Nineteen OCD subjects, free of psychiatric medications and depression, and 19 matched healthy controls underwent PET scans following injection of [11C]MDL 100907. Total distribution volumes (VT) were derived by kinetic analysis using the arterial input function. Two measures of 5-HT2A availability were computed (BPND and BPP). Groups were compared using a region of interest (ROI) analysis and voxelwise analysis of spatially normalized parametric maps. ROIs included cortical regions (orbitofrontal, dorsolateral prefrontal, medial prefrontal, anterior cingulate, temporal, parietal, occipital, and insular cortex) and limbic regions (entorhinal cortex, parahippocampal gyrus, and medial temporal lobe). Results No significant group differences were observed in [11C]MDL 100907 BPND or BPP in the ROIs or in the voxelwise analysis of BPND maps. There was a significant correlation in the orbitofrontal cortex between [11C] MDL 100907 binding and age of onset, with earlier age of onset associated with higher binding. Conclusions In contrast to prior reports, people with OCD (free of psychiatric medications and depression) are not characterized as a group by major changes in 5-HT2A availability in cortical or limbic brain regions. Further research is warranted to examine potential differences in 5-HT2A availability between early and late onset OCD and to assess 5-HT2A function in relation to other neurotransmitter systems implicated in OCD. PMID:21855857

  11. Sensitivity analysis for liver iron measurement through neutron stimulated emission computed tomography: a Monte Carlo study in GEANT4

    NASA Astrophysics Data System (ADS)

    Agasthya, G. A.; Harrawood, B. C.; Shah, J. P.; Kapadia, A. J.

    2012-01-01

    Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive imaging modality to detect and quantify iron overload in the human liver. NSECT uses gamma photons emitted by the inelastic interaction between monochromatic fast neutrons and iron nuclei in the body to detect and quantify the disease. Previous simulated and physical experiments with phantoms have shown that NSECT has the potential to accurately diagnose iron overload with reasonable levels of radiation dose. In this work, we describe the results of a simulation study conducted to determine the sensitivity of the NSECT system for hepatic iron quantification in patients of different sizes. A GEANT4 simulation of the NSECT system was developed with a human liver and two torso sizes corresponding to small and large patients. The iron concentration in the liver ranged between 0.5 and 20 mg g-1,In this paper all iron concentrations with units mg g-1 refer to wet weight concentrations. corresponding to clinically reported iron levels in iron-overloaded patients. High-purity germanium gamma detectors were simulated to detect the emitted gamma spectra, which were background corrected using suitable water phantoms and analyzed to determine the minimum detectable level (MDL) of iron and the sensitivity of the NSECT system. These analyses indicate that for a small patient (torso major axis = 30 cm) the MDL is 0.5 mg g-1 and sensitivity is ˜13 ± 2 Fe counts/mg/mSv and for a large patient (torso major axis = 40 cm) the values are 1 mg g-1 and ˜5 ± 1 Fe counts/mg/mSv, respectively. The results demonstrate that the MDL for both patient sizes lies within the clinically significant range for human iron overload.

  12. Examining Endogenous Dopamine in Treated Schizophrenia using [11C]-(+)-PHNO Positron Emission Tomography: A Pilot study

    PubMed Central

    Caravaggio, Fernando; Borlido, Carol; Wilson, Alan; Graff-Guerrero, Ariel

    2015-01-01

    Background Using positron emission tomography (PET) it is possible to estimate endogenous dopamine (DA) occupying D2/3 receptors (D2/3R) in the living human brain. Persons with schizophrenia (SZ) (previously medicated and naïve) have increased endogenous DA occupying D2/3R in the caudate. It is unknown whether currently medicated patients demonstrate increased DA levels at D2/3R. Moreover, DA levels have not been estimated in SZ using agonist radiotracers, which may offer a more sensitive quantification over antagonists. Methods Using the agonist radiotracer [11C]-(+)-PHNO, DA levels were estimated at D2/3R (ΔBPND) in three patients with SZ (Male, Mage=30±16). Patients were currently being treated long-term with Olanzapine (147±88 nmol/L). Results were compared to ten healthy controls (HC’s). Results Medicated persons with SZ had greater ΔBPND in the left caudate (U=2, Z=−2.20, p=.03) and right putamen (U=2, Z=−2.20, p=.03). No differences were observed in the ventral striatum or globus pallidus. Conclusions It is possible to estimate endogenous DA at D2/3R in SZ patients currently taking antipsychotics. Despite medication, patients continue to have increased endogenous DA at D2/3R. This lends more biological support to the clinical observation that relapses in symptoms can occur in the face of complete antipsychotic discontinuation. Future studies with larger samples are warranted. PMID:25814099

  13. Apomorphine effect on pain threshold in Parkinson's disease: a clinical and positron emission tomography study.

    PubMed

    Dellapina, Estelle; Gerdelat-Mas, Angélique; Ory-Magne, Fabienne; Pourcel, Laure; Galitzky, Monique; Calvas, Fabienne; Simonetta-Moreau, Marion; Thalamas, Claire; Payoux, Pierre; Brefel-Courbon, Christine

    2011-01-01

    Patients with Parkinson's disease (PD) frequently experience pain that could be in part due to central modification of nociception. In this randomized controlled double blind study, we compared the effect of apomorphine versus placebo on pain thresholds and pain-induced cerebral activity in 25 patients with PD. Subjective pain threshold (using thermal stimulation, thermotest), objective pain threshold (nociceptive flexion reflex), and cerebral activity (H(2)(15)O PET) during noxious and innocuous stimulations were performed. Neither subjective nor objective pain thresholds nor pain activation profile were modified by apomorphine compared with placebo in 25 PD patients. Apomorphine has no effect on pain processing in PD. We suggest that other monoamine systems than dopaminergic system could be involved.

  14. Are there radiographic, metabolic, and prognostic differences between cavitary and noncavitary nonsmall cell lung carcinoma? A retrospective fluorodeoxyglucose positron emission tomography/computed tomography study

    PubMed Central

    Nguyen, Nghi C.; Abhishek, Kumar; Nyon, Samuel; Farghaly, Hussein Rabie S.; Osman, Medhat M.; Reimers, Hans-Joachim

    2016-01-01

    AIMS: The prognosis of nonsmall cell lung cancer with cavitation (NSCLC-c) is not well-known. We compared the positron emission tomography/computed tomography (PET/CT) findings and survival data of patients with NSCLC-c patients with those without cavitation (NSCLC-nc). METHODS: Between 7/2004 and 6/2007, cavitary lung lesions were identified in 46/248 patients undergoing fluorodeoxyglucose (FDG) PET/CT for lung nodule characterization or lung cancer staging. Within the same period, 40 of 202 patients with NSCLC-nc were randomly selected for comparison. The primary was assessed by location, size, cell type, and standardized uptake value (SUV). Disease stage was determined according to American Joint Committee on Cancer guidelines for lung cancer. Kaplan–Meier method was used for survival analysis and Cox regression to assess the effect of clinical and imaging variables on survival. RESULTS: NSCLC-c was found in 87% of patients that had a cavitary lung lesion at PET/CT. Squamous cell carcinoma, primary size and primary-to-liver SUV ratio differed significantly between NSCLC-c and NSCLC-nc, whereas age, gender, primary location, primary SUV, type of treatment, and disease stage did not. Median survival and overall 5-year survival were 19 months and 24% for NSCLC-c, and 31 months and 31% for NSCLC-nc, P = 0.23. Disease stage was the only predictor of survival. CONCLUSION: Cavitary lung lesions in patients undergoing FDG PET/CT harbor a significant risk for cancer. NSCLC-c is associated with squamous cell carcinoma, larger size, and greater FDG metabolism compared with NSCLC-nc, although these variables may not be predictive of survival. Nonetheless, PET/CT contributes to accurate staging and has an indirect impact on prognosis. PMID:26933457

  15. Positron emission tomography in generalized seizures

    SciTech Connect

    Theodore, W.H.; Brooks, R.; Margolin, R.; Patronas, N.; Sato, S.; Porter, R.J.; Mansi, L.; Bairamian, D.; DiChiro, G.

    1985-05-01

    The authors used /sup 18/F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to study nine patients with clinical absence or generalized seizures. One patient had only absence seizures, two had only generalized tonic-clonic seizures, and six had both seizure types. Interictal scans in eight failed to reveal focal or lateralized hypometabolism. No apparent abnormalities were noted. Two patients had PET scans after isotope injection during hyperventilation-induced generalized spike-wave discharges. Diffusely increased metabolic rates were found in one compared with an interictal scan, and in another compared with control values. Another patient had FDG injected during absence status: EEG showed generalized spike-wave discharges (during which she was unresponsive) intermixed with slow activity accompanied by confusion. Metabolic rates were decreased, compared with the interictal scan, throughout both cortical and subcortical structures. Interictal PET did not detect specific anatomic regions responsible for absence seizure onset in any patient, but the results of the ictal scans did suggest that pathophysiologic differences exist between absence status and single absence attacks.

  16. Therapy response evaluation with positron emission tomography-computed tomography.

    PubMed

    Segall, George M

    2010-12-01

    Positron emission tomography-computed tomography with F-18-fluorodeoxyglucose is widely used for evaluation of therapy response in patients with solid tumors but has not been as readily adopted in clinical trials because of the variability of acquisition and processing protocols and the absence of universal response criteria. Criteria proposed for clinical trials are difficult to apply in clinical practice, and gestalt impression is probably accurate in individual patients, especially with respect to the presence of progressive disease and complete response. Semiquantitative methods of determining tissue glucose metabolism, such as standard uptake value, can be a useful descriptor for levels of tissue glucose metabolism and changes in response to therapy if technical quality control measures are carefully maintained. The terms partial response, complete response, and progressive disease are best used in clinical trials in which the terms have specific meanings and precise definitions. In clinical practice, it may be better to use descriptive terminology agreed upon by imaging physicians and clinicians in their own practice. PMID:21147376

  17. Single-photon emission computed tomography (SPECT): Applications and potential

    SciTech Connect

    Holman, B.L.; Tumeh, S.S. )

    1990-01-26

    Single-photon emission computed tomography has received increasing attention as radiopharmaceuticals that reflect perfusion, metabolism, and receptor and cellular function have become widely available. Perfusion single-photon emission computed tomography of the brain provides functional information useful for the diagnosis and management of stroke, dementia, and epilepsy. Single-photon emission computed tomography has been applied to myocardial, skeletal, hepatic, and tumor scintigraphy, resulting in increased diagnostic accuracy over planar imaging because background activity and overlapping tissues interfere far less with activity from the target structure when tomographic techniques are used. Single-photon emission computed tomography is substantially less expensive and far more accessible than positron emission tomography and will become an increasingly attractive alternative for transferring the positron emission tomography technology to routine clinical use.

  18. Single-photon emission computed tomography and positron-emission tomography assays for tissue oxygenation.

    PubMed

    Chapman, J D; Schneider, R F; Urbain, J L; Hanks, G E

    2001-01-01

    Radiotherapy prescription can now be customized to target the major mechanism(s) of resistance of individual tumors. In that regard, functional imaging techniques should be exploited to identify the dominant mechanism(s). Tumor biology research has identified several mechanisms of tumor resistance that may be unique to radiation treatments. These fall into 3 broad areas associated with (1) tumor hypoxic fraction, (2) tumor growth rate, (3) and the intrinsic radiosensitivity of tumor clonogens. Imaging research has markers in various stages of development for quantifying relevant information about each of these mechanisms, and those that measure tumor oxygenation and predict for radioresistance are the most advanced. Positron-emission tomography (PET) measurement of oxygen 15 has yielded important information, particularly about brain tissue perfusion, metabolism, and function. Indirect markers of tumor hypoxia have exploited the covalent binding of bioreductive intermediates of azomycin-containing compounds whose uptakes are inversely proportional to intracellular oxygen concentrations. Pilot clinical studies with single-photon emission computed tomography (SPECT) and PET detection of radiolabeled markers to tumor hypoxia have been reported. Recently, other studies have attempted to exploit the reduction properties of both technetium and copper chelates for the selective deposition of radioactive metals in hypoxic tissues. A growing number of potentially useful isotopes are now available for labeling several novel chemicals that could have the appropriate specificity and sensitivity. Preclinical studies with "microSPECT" and "microPET" will be important to define the optimal radiodiagnostic(s) for measuring tissue oxygenation and for determining the time after their administration for optimal hypoxic signal acquisition. Radiolabeled markers of growth kinetics and intrinsic radiosensitivity of cells in solid tumors are also being developed. We conclude that

  19. Positron Emission Tomography: Its 65 years

    NASA Astrophysics Data System (ADS)

    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.

  20. The distribution of cerebral muscarinic acetylcholine receptors in vivo in patients with dementia. A controlled study with 123IQNB and single photon emission computed tomography

    SciTech Connect

    Weinberger, D.R.; Gibson, R.; Coppola, R.; Jones, D.W.; Molchan, S.; Sunderland, T.; Berman, K.F.; Reba, R.C. )

    1991-02-01

    A high-affinity muscarinic receptor antagonist, 123IQNB (3-quinuclidinyl-4-iodobenzilate labeled with iodine 123), was used with single photon emission computed tomography to image muscarinic acetylcholine receptors in 14 patients with dementia and in 11 healthy controls. High-resolution single photon emission computed tomographic scanning was performed 21 hours after the intravenous administration of approximately 5 mCi of IQNB. In normal subjects, the images of retained ligand showed a consistent regional pattern that correlated with postmortem studies of the relative distribution of muscarinic receptors in the normal human brain, having high radioactivity counts in the basal ganglia, occipital cortex, and insular cortex, low counts in the thalamus, and virtually no counts in the cerebellum. Eight of 12 patients with a clinical diagnosis of Alzheimer's disease had obvious focal cortical defects in either frontal or posterior temporal cortex. Both patients with a clinical diagnosis of Pick's disease had obvious frontal and anterior temporal defects. A region of interest statistical analysis of relative regional activity revealed a significant reduction bilaterally in the posterior temporal cortex of the patients with Alzheimer's disease compared with controls. This study demonstrates the practicability of acetylcholine receptor imaging with 123IQNB and single photon emission computed tomography. The data suggest that focal abnormalities in muscarinic binding in vivo may characterize some patients with Alzheimer's disease and Pick's disease, but further studies are needed to address questions about partial volume artifacts and receptor quantification.

  1. Level Set Method for Positron Emission Tomography

    PubMed Central

    Chan, Tony F.; Li, Hongwei; Lysaker, Marius; Tai, Xue-Cheng

    2007-01-01

    In positron emission tomography (PET), a radioactive compound is injected into the body to promote a tissue-dependent emission rate. Expectation maximization (EM) reconstruction algorithms are iterative techniques which estimate the concentration coefficients that provide the best fitted solution, for example, a maximum likelihood estimate. In this paper, we combine the EM algorithm with a level set approach. The level set method is used to capture the coarse scale information and the discontinuities of the concentration coefficients. An intrinsic advantage of the level set formulation is that anatomical information can be efficiently incorporated and used in an easy and natural way. We utilize a multiple level set formulation to represent the geometry of the objects in the scene. The proposed algorithm can be applied to any PET configuration, without major modifications. PMID:18354724

  2. Estimation of linear functionals in emission tomography

    SciTech Connect

    Kuruc, A.

    1995-08-01

    In emission tomography, the spatial distribution of a radioactive tracer is estimated from a finite sample of externally-detected photons. We present an algorithm-independent theory of statistical accuracy attainable in emission tomography that makes minimal assumptions about the underlying image. Let f denote the tracer density as a function of position (i.e., f is the image being estimated). We consider the problem of estimating the linear functional {Phi}(f) {triple_bond} {integral}{phi}(x)f(x) dx, where {phi} is a smooth function, from n independent observations identically distributed according to the Radon transform of f. Assuming only that f is bounded above and below away from 0, we construct statistically efficient estimators for {Phi}(f). By definition, the variance of the efficient estimator is a best-possible lower bound (depending on and f) on the variance of unbiased estimators of {Phi}(f). Our results show that, in general, the efficient estimator will have a smaller variance than the standard estimator based on the filtered-backprojection reconstruction algorithm. The improvement in performance is obtained by exploiting the range properties of the Radon transform.

  3. [Positron emission tomography/computed tomography in follow-up programmes for patients with colorectal cancer].

    PubMed

    Hansen, Anne Fogh; Jensen, Mads Radmer; Nordholm-Carstensen, Andreas

    2016-09-12

    The current follow-up programmes for patients with colorectal cancer (CRC) after curative surgery do not include 18F-fluorodeoxyglucose-positron emission tomography (PET). Several small studies on selected patient populations indicate a high sensitivity of PET/computed tomography (CT) on visualizing relapse in patients with CRC after curative surgery. Therefore, PET/CT could probably be valuable in patients with unexplained increase in carcinoembryonic antigen level or a clinical suspicion of relapse, but PET/CT is not recommended as a standard in follow-up after CRC. PMID:27649583

  4. D2 dopamine receptors in neuroleptic-naive schizophrenic patients. A positron emission tomography study with (11C)raclopride

    SciTech Connect

    Farde, L.; Wiesel, F.A.; Stone-Elander, S.; Halldin, C.; Nordstroem, A.L.H.; Hall, H.; Sedvall, G. )

    1990-03-01

    Several groups have reported increased densities of D2 dopamine receptors in the basal ganglia of schizophrenic brains postmortem. The significance of this finding has been questioned, since an upregulation of receptor number may be a neuronal response to neuroleptic drug treatment. We have used positron emission tomography and ({sup 11}C)raclopride to examine central D2 dopamine receptor binding in 20 healthy subjects and 18 newly admitted, young, neuroleptic-naive patients with schizophrenia. An in vivo saturation procedure was applied for quantitative determination of D2 dopamine receptor density (Bmax) and affinity (Kd). When the two groups were compared, no significant difference in Bmax or Kd values was found in the putamen or the caudate nucleus. The hypothesis of generally elevated central D2 dopamine receptor densities in schizophrenia was thus not supported by the present findings. In the patients but not in the healthy controls, significantly higher densities were found in the left than in the right putamen but not in the caudate nucleus.

  5. Cerebral organization in a right-handed trilingual patient with right-hemisphere speech: a positron emission tomography study.

    PubMed

    Klein, Denise; Milner, Brenda; Zatorre, Robert J; Visca, Regina; Olivier, André

    2002-01-01

    Using the method of positron emission tomography, combined with word-generation tasks, we had the opportunity to examine the cerebral representation of multiple languages in the brain in a right-handed patient, RA, with known right-hemisphere speech representation as determined by intracarotid sodium amobarbital testing. Similar patterns of cerebral blood flow were observed across all three languages (French, Spanish and English), when synonym generation was compared with a silent resting baseline. In particular, several regions in the right inferior frontal cortex were activated. These foci are in locations corresponding to those observed in the left hemisphere in normal right-handed volunteers with presumed left-hemisphere dominance, and in patients known to be left-hemisphere dominant for speech. The lack of anatomical separation of the three languages within the same individual, who acquired two languages early and one language later in life, suggests that at least at this single-word level of analysis, age of acquisition was not a significant factor in the determining of functional organization in the brain.

  6. [Assessing myocardial perfusion with positron emission tomography].

    PubMed

    vom Dahl, J

    2001-11-01

    Positron emission tomography (PET) of the heart has gained widespread scientific and clinical acceptance with regard to two indications: 1) The detection of perfusion abnormalities by qualitative and semiquantitative analyses of perfusion images at rest and during physical or pharmacological stress using well-validated perfusion tracers, such as N-13 ammonia, Rb-82 rubidium chloride, or O-15 labeled water. 2) Viability imaging of myocardial regions with reduced contractility by combining perfusion measurements with substrate metabolism as assessed from F-18 deoxyglucose utilization. This overview summarizes the use of PET as a perfusion imaging method. With a sensitivity > 90% in combination with high specificity, PET is today the best-validated available nuclear imaging technique for the diagnosis of coronary artery disease (CAD). The short half-life of the perfusion tracers in combination with highly sophisticated hard- and software enables rapid PET studies with high patient throughput. The high diagnostic accuracy and the methological advantages as compared to conventional scintigraphy allows one to use PET perfusion imaging to detect subtle changes in the perfusion reserve for the detection of CAD in high risk but asymptomatic patients as well as in patients with proven CAD undergoing various treatment forms such as risk factor reduction or coronary revascularization. In patients following orthotopic heart transplantation, evolving transplant vasculopathy can be detected at an early stage. Quantitative PET imaging at rest allows for detection of myocardial viability since cellular survival is based on maintenance of a minimal perfusion and structural changes correlate to the degree of perfusion reduction. Furthermore, quantitative assessment of the myocardial perfusion reserve detects the magnitude and competence of collaterals in regions with occluded epicardial collaterals and, thus, imaging of several coronary distribution territories in one noninvasive

  7. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  8. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  9. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  10. Compact conscious animal positron emission tomography scanner

    DOEpatents

    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.

  11. Positron Emission Tomography with improved spatial resolution

    SciTech Connect

    Drukier, A.K.

    1990-04-01

    Applied Research Corporation (ARC) proposed the development of a new class of solid state detectors called Superconducting Granular Detectors (SGD). These new detectors permit considerable improvements in medical imaging, e.g. Positron Emission Tomography (PET). The biggest impact of this technique will be in imaging of the brain. It should permit better clinical diagnosis of such important diseases as Altzheimer's or schizophrenia. More specifically, we will develop an improved PET-imager; a spatial resolution 2 mm may be achievable with SGD. A time-of-flight capability(t {approx} 100 psec) will permit better contrast and facilitate 3D imaging. In the following, we describe the results of the first 9 months of the development.

  12. Imaging Tumor Metabolism Using Positron Emission Tomography

    PubMed Central

    Lewis, David Y.; Soloviev, Dmitry; Brindle, Kevin M.

    2015-01-01

    Positron emission tomography (PET) is an extraordinarily sensitive clinical imaging modality for interrogating tumor metabolism. Radiolabelled PET substrates can be traced at sub-physiological concentrations, allowing non-invasive imaging of metabolism and intra-tumoral heterogeneity in systems ranging from advanced cancer models to cancer patients in the clinic. There are a wide range of novel and more established PET radiotracers, which can be used to investigate various aspects of tumor metabolism, including carbohydrate, amino acid and fatty acid metabolism. In this review we will briefly discuss the more established metabolic tracers and describe recent work on the development of new tracers. Some of the unanswered questions in tumor metabolism will be considered alongside new technical developments, such as combined PET/MRI machines, that could provide new imaging solutions to some of the outstanding diagnostic challenges facing modern cancer medicine. PMID:25815854

  13. Bayesian image reconstruction: Application to emission tomography

    SciTech Connect

    Nunez, J.; Llacer, J.

    1989-02-01

    In this paper we propose a Maximum a Posteriori (MAP) method of image reconstruction in the Bayesian framework for the Poisson noise case. We use entropy to define the prior probability and likelihood to define the conditional probability. The method uses sharpness parameters which can be theoretically computed or adjusted, allowing us to obtain MAP reconstructions without the problem of the grey'' reconstructions associated with the pre Bayesian reconstructions. We have developed several ways to solve the reconstruction problem and propose a new iterative algorithm which is stable, maintains positivity and converges to feasible images faster than the Maximum Likelihood Estimate method. We have successfully applied the new method to the case of Emission Tomography, both with simulated and real data. 41 refs., 4 figs., 1 tab.

  14. Improved photomultiplier tube for positron emission tomography.

    PubMed

    Woldeselassie, T

    1989-05-01

    The paper describes an investigation in which it is shown that small positive voltage pulses applied to an external conductor placed against the photocathode of a photomultiplier tube can be used to switch the photocathode completely off for the duration of the pulses. This suggests that a photomultiplier tube with a multisegment photocathode can be constructed, the individual cathode segments of which can be switched off independently by means of such pulses. A theoretical explanation for the effect is provided with the aid of a simple circuit model for the photocathode. Analysis of the model also shows that it is possible to identify the particular cathode segment in which a photon is detected when a pulse is recorded at the phototube's anode. A phototube with these characteristics can have important implications for positron emission tomography, as it can provide improved spatial resolution, simultaneous multislice capability and the ability to eliminate distortion due to dead-time effects at high count rates.

  15. Positron emission tomography features of hidradenitis suppurativa

    PubMed Central

    Simpson, R C; Dyer, M J S; Entwisle, J; Harman, K E

    2011-01-01

    A 35-year-old male with classical Hodgkin's lymphoma (nodular sclerosing, grade 1 histology, clinical stage 2A) underwent a positron emission tomography (PET) scan to assess response to treatment. Half body CT PET imaging was obtained using a Siemens Biograph scanner from eyes to thighs. 405 MBq of 18-fluorodeoxyglucose (FDG) was injected with acquisition starting at 60 min. There was unexpected intense focal uptake in the superficial subcutaneous tissues of the abdomen, pelvis and lateral chest wall with overlying skin thickening seen on the CT component. This was initially of concern, but the patient was known to have a history of hidradenitis suppurativa (HS). On further examination, the radiological abnormalities corresponded to the clinical sites of involvement. To the best of our knowledge, this is the first documentation of the appearance of HS on PET scan. PMID:21750134

  16. Positron emission tomography and radiation oncology

    NASA Astrophysics Data System (ADS)

    Fullerton, PhD, Gary D.; Fox, MD, Peter; Phillips, MD, William T.

    2001-10-01

    Medical physics research is providing new avenues for addressing the fundamental problem of radiation therapy-how to provide a tumor-killing dose while reducing the dose to a non-lethal level for critical organs in adjacent portions of the patient anatomy. This talk reviews the revolutionary impact of Positron Emission Tomography on the practice of radiation oncology. The concepts of PET imaging and the development of "tumor" imaging methods using 18F-DG flouro-deoxyglucose are presented to provide the foundation for contemporary research and application to therapy. PET imaging influences radiation therapy decisions in multiple ways. Imaging of occult but viable tumor metastases eliminates misguided therapy attempts. The ability to distinguish viable tumor from scar tissue and necroses allows reduction of treatment portals and more selective treatments. Much research remains before the clinical benefits of these advances are fully realized.

  17. Anti-3-[18F]FACBC Positron Emission Tomography-Computerized Tomography and 111In-Capromab Pendetide Single Photon Emission Computerized Tomography-Computerized Tomography for Recurrent Prostate Carcinoma: Results of a Prospective Clinical Trial

    PubMed Central

    Schuster, David M.; Nieh, Peter T.; Jani, Ashesh B.; Amzat, Rianot; Bowman, F. DuBois; Halkar, Raghuveer K.; Master, Viraj A.; Nye, Jonathon A.; Odewole, Oluwaseun A.; Osunkoya, Adeboye O.; Savir-Baruch, Bital; Alaei-Taleghani, Pooneh; Goodman, Mark M.

    2014-01-01

    Purpose We prospectively evaluated the amino acid analogue positron emission tomography radiotracer anti-3-[18F]FACBC compared to ProstaScint® (111In-capromab pendetide) single photon emission computerized tomography-computerized tomography to detect recurrent prostate carcinoma. Materials and Methods A total of 93 patients met study inclusion criteria who underwent anti-3-[18F]FACBC positron emission tomography-computerized tomography plus 111In-capromab pendetide single photon emission computerized tomography-computerized tomography for suspected recurrent prostate carcinoma within 90 days. Reference standards were applied by a multidisciplinary board. We calculated diagnostic performance for detecting disease. Results In the 91 of 93 patients with sufficient data for a consensus on the presence or absence of prostate/bed disease anti-3-[18F]FACBC had 90.2% sensitivity, 40.0% specificity, 73.6% accuracy, 75.3% positive predictive value and 66.7% negative predictive value compared to 111In-capromab pendetide with 67.2%, 56.7%, 63.7%, 75.9% and 45.9%, respectively. In the 70 of 93 patients with a consensus on the presence or absence of extraprostatic disease anti-3-[18F]FACBC had 55.0% sensitivity, 96.7% specificity, 72.9% accuracy, 95.7% positive predictive value and 61.7% negative predictive value compared to 111In-capromabpendetide with10.0%, 86.7%, 42.9%, 50.0% and 41.9%, respectively. Of 77 index lesions used to prove positivity histological proof was obtained in 74 (96.1%). Anti-3-[18F]FACBC identified 14 more positive prostate bed recurrences (55 vs 41) and 18 more patients with extraprostatic involvement (22 vs 4). Anti-3-[18F]FACBC positron emission tomography-computerized tomography correctly up-staged 18 of 70 cases (25.7%) in which there was a consensus on the presence or absence of extraprostatic involvement. Conclusions Better diagnostic performance was noted for anti-3-[18F]FACBC positron emission tomography-computerized tomography than for 111In

  18. Central correlation of muscle sympathetic nerve activation during baroreflex unloading - a microneurography-positron emission tomography study.

    PubMed

    Krämer, Heidrun H; Ament, Stephan-Johann; Breimhorst, Markus; Klega, Andre; Schmieg, Katharina; Endres, Corina; Buchholz, Hans-Georg; Elam, Mikael; Schreckenberger, Mathias; Birklein, Frank

    2014-02-01

    The baroreceptor reflex controls spontaneous fluctuations in blood pressure. One major control variable of the baroreflex is the sympathetic vasoconstrictor activity to muscles [MSNA; burst frequency (BF) and burst incidence (BI)], which can be quantitatively assessed by microneurography. We aimed to investigate the central regions involved in baroreflex regulation of MSNA. Healthy men (mean age 25 years) participated in three experimental sessions. (i) Microneurography recordings of MSNA from the left peroneal nerve during rest and baroreflex unloading, induced by lower body negative pressure (LBNP; -40 mmHg). If MSNA could be reliably recorded throughout this procedure (n = 15), the subjects entered the positron emission tomography (PET) experiments. The two PET sessions took place in a randomised order. Cerebral glucose metabolism (18-fluorodeoxyglucose) was analysed after: (ii) baroreflex unloading (LBNP); and (iii) control condition (lying in the LBNP chamber without suction). The PET data were analysed employing SPM8. LBNP elicited a significant increase in MSNA in all successfully recorded subjects (BI: P = 0.001; F = 5.54; BF: P < 0.001; F = 36.59). As compared with the control condition, LBNP was associated with increased PET regional glucose metabolism bilaterally in the orbitofrontal cortex (OFC; BA 11, 47). Related to the rise of BF, there was increased activation of the left OFC (BA 11); related to the rise of BI there was increased activation of the brainstem corresponding to the rostral ventrolateral medulla. Our data support a role for the ventrolateral medulla and the OFC in baroreflex-mediated control of MSNA in humans. PMID:24528135

  19. Single photon emission computed tomography in seizure disorders.

    PubMed Central

    Denays, R; Rubinstein, M; Ham, H; Piepsz, A; Noël, P

    1988-01-01

    Fourteen children with various seizure disorders were studied using a cerebral blood flow tracer, 123I iodoamphetamine (0.05 mCi/kg), and single photon emission computed tomography (SPECT). In the five patients with radiological lesions, SPECT showed congruent or more extensive abnormalities. Five of the nine children with a normal scan on computed tomography had abnormal SPECT studies consisting of focal hypoperfusion, diffuse hemispheric hypoperfusion, multifocal and bilateral hypoperfusion, or focal hyperperfusion. A focal lesion seen on SPECT has been found in children with tonic-clonic seizures suggesting secondarily generalised seizures. Moreover the pattern seen on SPECT seemed to be related to the clinical status. An extensive impairment found on SPECT was associated with a poor evolution in terms of intellectual performance and seizure frequency. Conversely all children with a normal result on SPECT had less than two seizures per year and normal neurological and intellectual development. Images Figure PMID:3264135

  20. Positron Emission Tomography Imaging of Atherosclerosis

    PubMed Central

    Orbay, Hakan; Hong, Hao; Zhang, Yin; Cai, Weibo

    2013-01-01

    Atherosclerosis-related cardiovascular events are the leading causes of death in the industrialized world. Atherosclerosis develops insidiously and the initial manifestation is usually sudden cardiac death, stroke, or myocardial infarction. Molecular imaging is a valuable tool to identify the disease at an early stage before fatal manifestations occur. Among the various molecular imaging techniques, this review mainly focuses on positron emission tomography (PET) imaging of atherosclerosis. The targets and pathways that have been investigated to date for PET imaging of atherosclerosis include: glycolysis, cell membrane metabolism (phosphatidylcholine synthesis), integrin αvβ3, low density lipoprotein (LDL) receptors (LDLr), natriuretic peptide clearance receptors (NPCRs), fatty acid synthesis, vascular cell adhesion molecule-1 (VCAM-1), macrophages, platelets, etc. Many PET tracers have been investigated clinically for imaging of atherosclerosis. Early diagnosis of atherosclerotic lesions by PET imaging can help to prevent the premature death caused by atherosclerosis, and smooth translation of promising PET tracers into the clinic is critical to the benefit of patients. PMID:24312158

  1. Resistive plate chambers in positron emission tomography

    NASA Astrophysics Data System (ADS)

    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.

  2. Positron Emission Tomography: A Basic Analysis

    NASA Astrophysics Data System (ADS)

    Kerbacher, M. E.; Deaton, J. W.; Phinney, L. C.; Mitchell, L. J.; Duggan, J. L.

    2007-10-01

    Positron Emission Tomography is useful in detecting biological abnormalities. The technique involves attaching radiotracers to a material used inside the body, in many cases glucose. Glucose is absorbed most readily in areas of unusual cell growth or uptake of nutrients so through natural processes the treated glucose highlights regions of tumors and other degenerative disorders such as Alzheimer's disease. The higher the concentration of isotopes, the more dynamic the area. Isotopes commonly used as tracers are 11C, 18F, 13N, and 15O due to their easy production and short half-lives. Once the tracers have saturated an area of tissue they are detected using coincidence detectors collinear with individual isotopes. As the isotope decays it emits a positron which, upon annihilating an electron, produces two oppositely directioned gamma rays. The PET machine consists of several pairs of detectors, each 180 degrees from their partner detector. When the oppositely positioned detectors are collinear with the area of the isotope, a computer registers the location of the isotope and can compile an image of the activity of the highlighted area based on the position and strength of the isotopes.

  3. Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yılmaz; Vatankulu, Betül; Uslu, Lebriz; Halac, Metin

    2016-01-01

    An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images. PMID:27385906

  4. Association between Cerebral Amyloid Deposition and Clinical Factors Including Cognitive Function in Geriatric Depression: Pilot Study Using Amyloid Positron Emission Tomography

    PubMed Central

    Kim, Hye-Geum; Kong, Eun-Jung; Cheon, Eun-Jin; Kim, Hae-Won; Koo, Bon-Hoon

    2016-01-01

    The purpose of this study was to explore the relationship between cerebral amyloid deposition and overall clinical factors including cognitive functions in geriatric depression by using 18F-florbetaben positron emission tomography. Thirteen subjects aged over 60 years who had a history of major depressive disorder and also had subjective memory complaint were included. Of all subjects, 3 subjects judged as amyloid positive, and the others judged as amyloid negative. Their memory, visuospatial functions and attention abilities were negatively correlated with amyloid deposition in specific brain regions, but their language and recognition abilities were not correlated with any region. The amyloid deposition of the whole brain region was significantly negatively correlated with immediate memory. PMID:27776391

  5. Single photon emission computed tomography in AIDS dementia complex

    SciTech Connect

    Pohl, P.; Vogl, G.; Fill, H.; Roessler, H.Z.; Zangerle, R.; Gerstenbrand, F.

    1988-08-01

    Single photon emission computed tomography (SPECT) studies were performed in AIDS dementia complex using IMP in 12 patients (and HM-PAO in four of these same patients). In all patients, SPECT revealed either multiple or focal uptake defects, the latter corresponding with focal signs or symptoms in all but one case. Computerized tomography showed a diffuse cerebral atrophy in eight of 12 patients, magnetic resonance imaging exhibited changes like atrophy and/or leukoencephalopathy in two of five cases. Our data indicate that both disturbance of cerebral amine metabolism and alteration of local perfusion share in the pathogenesis of AIDS dementia complex. SPECT is an important aid in the diagnosis of AIDS dementia complex and contributes to the understanding of the pathophysiological mechanisms of this disorder.

  6. Imaging local brain function with emission computed tomography

    SciTech Connect

    Kuhl, D.E.

    1984-03-01

    Positron emission tomography (PET) using /sup 18/F-fluorodeoxyglucose (FDG) was used to map local cerebral glucose utilization in the study of local cerebral function. This information differs fundamentally from structural assessment by means of computed tomography (CT). In normal human volunteers, the FDG scan was used to determine the cerebral metabolic response to conrolled sensory stimulation and the effects of aging. Cerebral metabolic patterns are distinctive among depressed and demented elderly patients. The FDG scan appears normal in the depressed patient, studded with multiple metabolic defects in patients with multiple infarct dementia, and in the patients with Alzheimer disease, metabolism is particularly reduced in the parietal cortex, but only slightly reduced in the caudate and thalamus. The interictal FDG scan effectively detects hypometabolic brain zones that are sites of onset for seizures in patients with partial epilepsy, even though these zones usually appear normal on CT scans. The future prospects of PET are discussed.

  7. Quantitative simultaneous positron emission tomography and magnetic resonance imaging

    PubMed Central

    Ouyang, Jinsong; Petibon, Yoann; Huang, Chuan; Reese, Timothy G.; Kolnick, Aleksandra L.; El Fakhri, Georges

    2014-01-01

    Abstract. Simultaneous positron emission tomography and magnetic resonance imaging (PET-MR) is an innovative and promising imaging modality that is generating substantial interest in the medical imaging community, while offering many challenges and opportunities. In this study, we investigated whether MR surface coils need to be accounted for in PET attenuation correction. Furthermore, we integrated motion correction, attenuation correction, and point spread function modeling into a single PET reconstruction framework. We applied our reconstruction framework to in vivo animal and patient PET-MR studies. We have demonstrated that our approach greatly improved PET image quality. PMID:26158055

  8. Positron emission tomography for the assessment of myocardial viability

    SciTech Connect

    Schelbert, H.R. )

    1991-09-01

    The detection of viable myocardium or ischemically injured myocardium with a reversible impairment of contractile function remains clinically important but challenging. Detection of reversible dysfunction and distinction from irreversible tissue injury by positron emission tomography is based on identification of preserved or even enhanced glucose metabolism with F-18 2-fluoro 2-deoxyglucose. Regional patterns of myocardial glucose utilization and blood flow, defined as perfusion-metabolism mismatches or matches, on positron emission tomography in patients with chronic or even acute ischemic heart disease are highly accurate in predicting the functional outcome after interventional revascularization. Compared with thallium-201 redistribution scintigraphy, positron emission tomography appears to be diagnostically more accurate, especially in patients with severely impaired left ventricular function. While larger clinical trials are needed for further confirmation, positron emission tomography has already proved clinically useful for stratifying patients with poor left ventricular function to the most appropriate therapeutic approach.

  9. Single versus multiple impulse control disorders in Parkinson's disease: an ¹¹C-raclopride positron emission tomography study of reward cue-evoked striatal dopamine release.

    PubMed

    Wu, Kit; Politis, Marios; O'Sullivan, Sean S; Lawrence, Andrew D; Warsi, Sarah; Bose, Subrata; Lees, Andrew J; Piccini, Paola

    2015-06-01

    Impulse control disorders (ICDs) are reported in Parkinson's disease (PD) in association with dopaminergic treatment. Approximately 25 % of patients with ICDs have multiple co-occurring ICDs (i.e. more than one diagnosed ICD). The extent to which dopaminergic neurotransmission in PD patients with multiple ICDs differs from those with only one diagnosed ICD is unknown. The aims of this study are: (1) to investigate dopamine neurotransmission in PD patients diagnosed with multiple ICDs, single ICDs and non-ICD controls in response to reward-related visual cues using positron emission tomography with (11)C-raclopride. (2) to compare clinical features of the above three groups. PD individuals with mulitple ICDs (n = 10), single ICD (n = 7) and no ICDs (n = 9) were recruited and underwent two positron emission tomography (PET) scans with (11)C-raclopride: one where they viewed neutral visual cues and the other where they viewed a range of visual cues related to different rewards. Individuals with both multiple ICDs and single ICDs showed significantly greater ventral striatal dopamine release compared to non-ICD PD individuals in response to reward cues, but the two ICD groups did not differ from each other in the extent of dopamine release. Subjects with multiple ICDs were, however, significantly more depressed, and had higher levels of impulsive sensation-seeking compared to subjects with single ICDs and without ICDs. This is the first study to compare dopamine neurotransmission using PET neuroimaging in PD subjects with multiple vs. single ICDs. Our results suggest that striatal dopamine neurotransmission is not directly related to the co-occurrence of ICDs in PD, potentially implicating non-dopaminergic mechanisms linked to depression; and suggest that physicians should be vigilant in managing depression in PD patients with ICDs.

  10. Combined positron emission tomography and computed tomography to visualize and quantify fluid flow in sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Fernø, M. A.; Gauteplass, J.; Hauge, L. P.; Abell, G. E.; Adamsen, T. C. H.; Graue, A.

    2015-09-01

    Here we show for the first time the combined positron emission tomography (PET) and computed tomography (CT) imaging of flow processes within porous rocks to quantify the development in local fluid saturations. The coupling between local rock structure and displacement fronts is demonstrated in exploratory experiments using this novel approach. We also compare quantification of 3-D temporal and spatial water saturations in two similar CO2 storage tests in sandstone imaged separately with PET and CT. The applicability of each visualization technique is evaluated for a range of displacement processes, and the favorable implementation of combining PET/CT for laboratory core analysis is discussed. We learn that the signal-to-noise ratio (SNR) is over an order of magnitude higher for PET compared with CT for the studied processes.

  11. Positron emission tomography imaging of prostate cancer

    PubMed Central

    Hong, Hao; Zhang, Yin; Sun, Jiangtao; Cai, Weibo

    2009-01-01

    Prostate cancer (PCa) is the second leading cause of cancer death among men in the United States. Positron emission tomography (PET), a non-invasive, sensitive, and quantitative imaging technique, can facilitate personalized management of PCa patients. There are two critical needs for PET imaging of PCa, early detection of primary lesions and accurate imaging of PCa bone metastasis, the predominant cause of death in PCa. Since the most widely used PET tracer in the clinic, 18F-fluoro-2-deoxy-2-D-glucose (18F-FDG), does not meet these needs, a wide variety of PET tracers have been developed for PCa imaging which span an enormous size range from small molecules to intact antibodies. In this review, we will first summarize small molecule-based PET tracers for PCa imaging, which measure certain biological events such as cell membrane metabolism, fatty acid synthesis, and receptor expression. Next, we will discuss radiolabeled amino acid derivatives (e.g. methionine, leucine, tryptophan, and cysteine analogs), which are primarily based on the increased amino acid transport of PCa cells. Peptide-based tracers for PET imaging of PCa, mostly based on the bombesin peptide and its derivatives which bind to the gastrin-releasing peptide receptor, will then be presented in detail. We will also cover radiolabeled antibodies and antibody fragments (e.g. diabodies and minibodies) for PET imaging of PCa, targeting integrin αvβ3, EphA2, the epidermal growth factor receptor, or the prostate stem cell antigen. Lastly, we will identify future directions for the development of novel PET tracers for PCa imaging, which may eventually lead to personalized management of PCa patients. PMID:19946787

  12. Radiofluorinated carbohydrates for positron emission tomography.

    PubMed

    Mun, Jiyoung

    2013-01-01

    2-Deoxy-2-[(18)F]fluoro-D-glucose (2-(18)FDG) has represented radiofluorinated carbohydrates as the most successful tracer for positron emission tomography (PET). 2-(18)FDG uptake depends on glucose metabolism, which is related to a disease progression. 2-(18)FDG has been widely used in oncology, neurology, cardiology, infectious diseases, and inflammation, to complement anatomical modalities such as CT and MRI. Followed by the success of 2-(18)FDG, various radiofluorinated carbohydrates have been evaluated as PET tracers, which include analogs of D-ribose, D-mannose, D-galactose, D-talose, D-fructose, D-allose, lactose, L-fucose, N-acetylneuraminic acid, and L-ascorbic acid. Among those radiofluorinated carbohydrates, several have implied potential for further development. 2-Deoxy-2-[(18)F]fluoro-D-galactose has been developed to assess liver function and diagnose hepatic carcinoma. 6-Deoxy-6-[(18)F]fluoro-D-fructose showed promising characteristics for diagnosis of breast cancer. Three radiofluorinated analogs of lactose have been designed as the substrates of the overexpressed hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein in peritumoral pancreatic tissue for early diagnosis of pancreatic cancer. The metabolism of 6-[(18)F]fluoro-L-fucose suggested that it is a bioactive analog of L-fucose in the synthesis of glycoconjugate macromolecules. 6-Deoxy-6-[(18)F]fluoro-L-ascorbic acid was evaluated to assess antioxidant function of L-ascorbic acid in rodent models of transient global ischemia and glutathione deficiency.

  13. An online emission spectral tomography system with digital signal processor.

    PubMed

    Wan, Xiong; Xiong, Wenlin; Zhang, Zhimin; Chang, Fangfei

    2009-03-30

    Emission spectral tomography (EST) has been adopted to test the three-dimensional distribution parameters of fluid fields, such as burning gas, flame and plasma etc. In most cases, emission spectral data received by the video cameras are enormous so that the emission spectral tomography calculation is often time-consuming. Hence, accelerating calculation becomes the chief factor that one must consider for the practical application of EST. To solve the problem, a hardware implementation method was proposed in this paper, which adopted a digital signal processor (DSP) DM642 in an emission spectral tomography test system. The EST algorithm was fulfilled in the DSP, then calculation results were transmitted to the main computer via the user datagram protocol. Compared with purely VC++ software implementations, this new approach can decrease the calculation time significantly.

  14. Domain-related differentiation of working memory in the Japanese macaque (Macaca fuscata) frontal cortex: a positron emission tomography study.

    PubMed

    Kojima, T; Onoe, H; Hikosaka, K; Tsutsui, K; Tsukada, H; Watanabe, M

    2007-04-01

    The lateral prefrontal cortex (LPFC) is important for working memory (WM) task performance. Neuropsychological and neurophysiological studies in monkeys suggest that the lateral prefrontal cortex is functionally segregated based on the working memory domain (spatial vs. non-spatial). However, this is not supported by most human neuroimaging studies, and the discrepancy might be due to differences in methods and/or species (monkey neuropsychology/physiology vs. human neuroimaging). We used positron emission topography to examine the functional segregation of the lateral prefrontal cortex of Japanese macaques (Macaca fuscata) that showed near 100% accuracy on spatial and non-spatial working memory tasks. Compared with activity during the non-working memory control tasks, the dorsolateral prefrontal cortex (DLPFC) was more active during the non-spatial, but not during the spatial, working memory task, although a muscimol microinjection into the dorsolateral prefrontal cortex significantly impaired the performance of both working memory tasks. A direct comparison of the brain activity between the two working memory tasks revealed no differences within the lateral prefrontal cortex, whereas the premotor area was more active during the spatial working memory task. Comparing the delay-specific activity, which did not include task-associated stimulus/response-related activity, revealed more spatial working memory-related activity in the posterior parietal and premotor areas, and more non-spatial working memory-related activity in the dorsolateral prefrontal cortex and hippocampus. These results suggest that working memory in the monkey brain is segregated based on domain, not within the lateral prefrontal cortex but rather between the posterior parietal-premotor areas and the dorsolateral prefrontal-hippocampus areas.

  15. Positron emission tomography of lung tumors and mediastinal lymph nodes using [18F]fluorodeoxyglucose. The Members of the PET-Lung Tumor Study Group.

    PubMed

    Scott, W J; Schwabe, J L; Gupta, N C; Dewan, N A; Reeb, S D; Sugimoto, J T

    1994-09-01

    Positron emission tomography detects increased glucose uptake in malignant tissue using the glucose analogue [2-18F]fluoro-2-deoxy-D-glucose. We reviewed the scans obtained in 62 patients with lung tumors. All had undergone computed tomography and had tissue-based diagnoses: 22 had adenocarcinomas, 12 had squamous cell carcinomas, 13 had other malignancies, 1 had organizing pneumonia, 1 had a hamartoma, and 13 had granulomas. Positron emission tomography with [2-18F]fluoro-2-deoxy-D-glucose identified 44 of 47 malignancies. Two of three false-negative findings were tumors that were 1 cm2 or less and the other was a bronchioloalveolar carcinoma. All three false-positive findings were granulomas. The sensitivity and specificity of the technique were 93.6% and 80%, respectively, and the positive and negative predictive values were 93.6% and 80%, respectively. The differential uptake ratio was determined in all 62 patients. The mean differential uptake ratio (+/- the standard error of the mean) for malignant tumors was 6.4 +/- 0.56 and that for benign tumors was 1.14 +/- 0.26 (p < 0.0001, t test). Twenty-five of the patients had N2 lymph nodes evaluated pathologically. Positron emission tomography with [2-18F]fluoro-2-deoxy-D-glucose identified negative N2 nodes in 19 of 22 patients (86%) with negative nodes and positive N2 nodes in 2 of 3 patients (66%) with positive nodes, including one instance missed by computed tomography.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7944691

  16. A Pilot Study Measuring the Distribution and Permeability of a Vaginal HIV Microbicide Gel Vehicle Using Magnetic Resonance Imaging, Single Photon Emission Computed Tomography/Computed Tomography, and a Radiolabeled Small Molecule.

    PubMed

    Fuchs, Edward J; Schwartz, Jill L; Friend, David R; Coleman, Jenell S; Hendrix, Craig W

    2015-11-01

    Vaginal microbicide gels containing tenofovir have proven effective in HIV prevention, offering the advantage of reduced systemic toxicity. We studied the vaginal distribution and effect on mucosal permeability of a gel vehicle. Six premenopausal women were enrolled. In Phase 1, a spreading gel containing (99m)technetium-DTPA ((99m)Tc) radiolabel and gadolinium contrast for magnetic resonance imaging (MRI) was dosed intravaginally. MRI was obtained at 0.5, 4, and 24 h, and single photon emission computed tomography with conventional computed tomography (SPECT/CT) at 1.5, 5, and 25 h postdosing. Pads and tissues were measured for activity to determine gel loss. In Phase 2, nonoxynol-9 (N-9), containing (99m)Tc-DTPA, was dosed as a permeability control; permeability was measured in blood and urine for both phases. SPECT/CT showed the distribution of spreading gel throughout the vagina with the highest concentration of radiosignal in the fornices and ectocervix; signal intensity diminished over 25 h. MRI showed the greatest signal accumulation in the fornices, most notably 1-4 h postdosing. The median (interquartile range) isotope signal loss from the vagina through 6 h was 29.1% (15.8-39.9%). Mucosal permeability to (99m)Tc-DTPA following spreading gel was negligible, in contrast to N-9, with detectable radiosignal in plasma, peaking at 8 h (5-12). Following spreading gel dosing, 0.004% (0.001-2.04%) of the radiosignal accumulated in urine over 12 h compared to 8.31% (7.07-11.01%) with N-9, (p=0.043). Spreading gel distributed variably throughout the vagina, persisting for 24 h, with signal concentrating in the fornices and ectocervix. The spreading gel had no significant effect on vaginal mucosal permeability.

  17. A Pilot Study Measuring the Distribution and Permeability of a Vaginal HIV Microbicide Gel Vehicle Using Magnetic Resonance Imaging, Single Photon Emission Computed Tomography/Computed Tomography, and a Radiolabeled Small Molecule.

    PubMed

    Fuchs, Edward J; Schwartz, Jill L; Friend, David R; Coleman, Jenell S; Hendrix, Craig W

    2015-11-01

    Vaginal microbicide gels containing tenofovir have proven effective in HIV prevention, offering the advantage of reduced systemic toxicity. We studied the vaginal distribution and effect on mucosal permeability of a gel vehicle. Six premenopausal women were enrolled. In Phase 1, a spreading gel containing (99m)technetium-DTPA ((99m)Tc) radiolabel and gadolinium contrast for magnetic resonance imaging (MRI) was dosed intravaginally. MRI was obtained at 0.5, 4, and 24 h, and single photon emission computed tomography with conventional computed tomography (SPECT/CT) at 1.5, 5, and 25 h postdosing. Pads and tissues were measured for activity to determine gel loss. In Phase 2, nonoxynol-9 (N-9), containing (99m)Tc-DTPA, was dosed as a permeability control; permeability was measured in blood and urine for both phases. SPECT/CT showed the distribution of spreading gel throughout the vagina with the highest concentration of radiosignal in the fornices and ectocervix; signal intensity diminished over 25 h. MRI showed the greatest signal accumulation in the fornices, most notably 1-4 h postdosing. The median (interquartile range) isotope signal loss from the vagina through 6 h was 29.1% (15.8-39.9%). Mucosal permeability to (99m)Tc-DTPA following spreading gel was negligible, in contrast to N-9, with detectable radiosignal in plasma, peaking at 8 h (5-12). Following spreading gel dosing, 0.004% (0.001-2.04%) of the radiosignal accumulated in urine over 12 h compared to 8.31% (7.07-11.01%) with N-9, (p=0.043). Spreading gel distributed variably throughout the vagina, persisting for 24 h, with signal concentrating in the fornices and ectocervix. The spreading gel had no significant effect on vaginal mucosal permeability. PMID:26077739

  18. Distinct neural correlates of visual long-term memory for spatial location and object identity: a positron emission tomography study in humans.

    PubMed Central

    Moscovitch, C; Kapur, S; Köhler, S; Houle, S

    1995-01-01

    The purpose of the present study was to investigate by using positron emission tomography (PET) whether the cortical pathways that are involved in visual perception of spatial location and object identity are also differentially implicated in retrieval of these types of information from episodic long-term memory. Subjects studied a set of displays consisting of three unique representational line drawings arranged in different spatial configurations. Later, while undergoing PET scanning, subjects' memory for spatial location and identity of the objects in the displays was tested and compared to a perceptual baseline task involving the same displays. In comparison to the baseline task, each of the memory tasks activated both the dorsal and the ventral pathways in the right hemisphere but not to an equal extent. There was also activation of the right prefrontal cortex. When PET scans of the memory tasks were compared to each other, areas of activation were very circumscribed and restricted to the right hemisphere: For retrieval of object identity, the area was in the inferior temporal cortex in the region of the fusiform gyrus (area 37), whereas for retrieval of spatial location, it was in the inferior parietal lobule in the region of the supramarginal gyrus (area 40). Thus, our study shows that distinct neural pathways are activated during retrieval of information about spatial location and object identity from long-term memory. Images Fig. 2 PMID:7731972

  19. Histone Deacetylase Inhibitor MS-275 Exhibits Poor Brain Penetration: Pharmacokinetic Studies of [11C]MS-275 using Positron Emission Tomography

    PubMed Central

    2009-01-01

    MS-275 (entinostat) is a histone deacetylase (HDAC) inhibitor currently in clinical trials for the treatment of several types of cancer. Recent reports have noted that MS-275 can cross the blood−brain barrier (BBB) and cause region-specific changes in rodent brain histone acetylation. To characterize the pharmacokinetics and distribution of MS-275 in the brain using positron emission tomography (PET), we labeled the carbamate carbon of MS-275 with carbon-11. Using PET, we determined that [11C]MS-275 has low uptake in brain tissue when administered intravenously to nonhuman primates. In rodent studies, we observed that pharmacokinetics and brain accumulation of [11C]MS-275 were not changed by the coadministration of large doses of unlabeled MS-275. These results, which both highlight the poor brain penetration of MS-275, clearly suggest its limitation as a therapeutic agent for the central nervous system (CNS). Moreover, our study demonstrates the effectiveness of PET at providing brain pharmacokinetic data for HDAC inhibitors. These data are important not only for the development of new compounds for peripheral cancer treatment (where CNS exclusion is often advantageous) but also for the treatment of neurological disorders (where CNS penetration is critical). PMID:20657706

  20. Histone Deacetylase Inhibitor MS-275 Exhibits Poor Brain Penetration: Pharmacokinetic Studies of [11C]MS-275 using Positron Emission Tomography

    SciTech Connect

    Hooker, J.M.; Hooker, J.M.; Kim, S.W.; Alexoff, D.; Xu, Y.; Shea, C.; Reid, A.; Volkow, N.D.; Fowler, J.S.

    2009-10-01

    MS-275 (entinostat) is a histone deacetylase (HDAC) inhibitor currently in clinical trials for the treatment of several types of cancer. Recent reports have noted that MS-275 can cross the blood-brain barrier (BBB) and cause region-specific changes in rodent brain histone acetylation. To characterize the pharmacokinetics and distribution of MS-275 in the brain using positron emission tomography (PET), we labeled the carbamate carbon of MS-275 with carbon-11. Using PET, we determined that [{sup 11}C]MS-275 has low uptake in brain tissue when administered intravenously to nonhuman primates. In rodent studies, we observed that pharmacokinetics and brain accumulation of [{sup 11}C]MS-275 were not changed by the coadministration of large doses of unlabeled MS-275. These results, which both highlight the poor brain penetration of MS-275, clearly suggest its limitation as a therapeutic agent for the central nervous system (CNS). Moreover, our study demonstrates the effectiveness of PET at providing brain pharmacokinetic data for HDAC inhibitors. These data are important not only for the development of new compounds for peripheral cancer treatment (where CNS exclusion is often advantageous) but also for the treatment of neurological disorders (where CNS penetration is critical).

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

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    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. PMID:25589818

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

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    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.

  3. Pigmented villonodular synovitis mimics metastases on fluorine 18 fluorodeoxyglucose position emission tomography-computed tomography

    PubMed Central

    Elumogo, Comfort O.; Kochenderfer, James N.; Civelek, A. Cahid

    2016-01-01

    Pigmented villonodular synovitis (PVNS) is a benign joint disease best characterized on magnetic resonance imaging (MRI). The role of fluorine 18 fluorodeoxyglucose (18F-FDG) position emission tomography-computed tomography (PET-CT) in the diagnosis or characterization remains unclear. PVNS displays as a focal FDG avid lesion, which can masquerade as a metastatic lesion, on PET-CET. We present a case of PVNS found on surveillance imaging of a lymphoma patient. PMID:27190776

  4. Distribution of 1-methyl-4-phneyl-1,2,3,6-tetrahydropyridine in experimental animals studied by positron emission tomography and whole body autoradiography

    SciTech Connect

    Hartvig, P.; Lindquist, N.G.; Aquilonius, S.M.; d'Argy, R.; Bergstroem, K.; Bondesson, U.; Eckernaes, S.A.; Gullberg, P.; Larsson, B.S.; Lindberg, B.

    1986-01-06

    1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a selective potent neurotoxin which has induced a syndrome similar to parkinsonism both in man and in monkeys. At autopsy degeneration of pigmented nerve cells in the pars compacta of the substantia nigra has been confirmed. The regional distribution of intravenously administered 1-(/sup 11/C-methyl)-4-phenyl-1,2,3,6-tetrahydropyridine (/sup 11/C-MPTP) in the brain of Rhesus monkeys was studied by positron emission tomography and the whole body distribution in mice was documented by autoradiography and by impulse counting of selected tissues. A rapid and high uptake of /sup 11/C-MPTP derived radioactivity was seen in areas corresponding to striatum and midbrain, including the substantia nigra area. Pretreatment of the monkey with spiperone, a selective dopamine receptor antagonist, did not alter uptake nor the kinetics of the /sup 11/C-MPTP derived radioactivity. Thus, /sup 11/C-MPTP does not have a high affinity for postsynaptic dopamine receptors. A remarkably high uptake of /sup 11/C-MPTP derived radioactivity was seen in the eye of the monkey. The selective uptake of radioactivity in the eye was also confirmed in pigmented but not in albino mice. The melanin affinity of MPTP may cause high intracellular concentrations of the compound or its metabolites in the melanin containing nerve cells in substantia nigra, which may explain the serious vulnerability of these neurons to MPTP. 30 references, 3 figures, 2 tables.

  5. Delta-9-Tetrahydrocannabinol-Induced Dopamine Release as a Function of Psychosis Risk: 18F-Fallypride Positron Emission Tomography Study

    PubMed Central

    Kuepper, Rebecca; Ceccarini, Jenny; Lataster, Johan; van Os, Jim; van Kroonenburgh, Marinus; van Gerven, Joop M. A.; Marcelis, Machteld; Van Laere, Koen; Henquet, Cécile

    2013-01-01

    Cannabis use is associated with psychosis, particularly in those with expression of, or vulnerability for, psychotic illness. The biological underpinnings of these differential associations, however, remain largely unknown. We used Positron Emission Tomography and 18F-fallypride to test the hypothesis that genetic risk for psychosis is expressed by differential induction of dopamine release by Δ9-THC (delta-9-tetrahydrocannabinol, the main psychoactive ingredient of cannabis). In a single dynamic PET scanning session, striatal dopamine release after pulmonary administration of Δ9-THC was measured in 9 healthy cannabis users (average risk psychotic disorder), 8 patients with psychotic disorder (high risk psychotic disorder) and 7 un-related first-degree relatives (intermediate risk psychotic disorder). PET data were analyzed applying the linear extension of the simplified reference region model (LSRRM), which accounts for time-dependent changes in 18F-fallypride displacement. Voxel-based statistical maps, representing specific D2/3 binding changes, were computed to localize areas with increased ligand displacement after Δ9-THC administration, reflecting dopamine release. While Δ9-THC was not associated with dopamine release in the control group, significant ligand displacement induced by Δ9-THC in striatal subregions, indicative of dopamine release, was detected in both patients and relatives. This was most pronounced in caudate nucleus. This is the first study to demonstrate differential sensitivity to Δ9-THC in terms of increased endogenous dopamine release in individuals at risk for psychosis. PMID:23936196

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

    PubMed

    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

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

    PubMed Central

    Frick, A; Ahs, F; Linnman, C; Jonasson, M; Appel, L; Lubberink, M; Långström, B; Fredrikson, M; Furmark, T

    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 [11C]GR205171. The Patlak Graphical plot using a cerebellar reference region was used to model the influx parameter, Ki measuring NK1 receptor availability. Voxel-wise statistical parametric mapping analyses revealed increased NK1 receptor availability specifically in the right amygdala in SAD patients relative to controls. Thus, we demonstrate that exaggerated social anxiety is related to enhanced NK1 receptor availability in the amygdala. This finding supports the contribution of NK1 receptors not only in animal models of stress and anxiety but also in humans with anxiety disorders. PMID:26151925

  8. Effects of point spread function-based image reconstruction on neuroreceptor binding in positron emission tomography study with [(11)C]FLB 457.

    PubMed

    Thongpraparn, Thonnapong; Ikoma, Yoko; Shiraishi, Takahiro; Yamaya, Taiga; Ito, Hiroshi

    2016-01-01

    The ordered subset expectation maximization with a point spread function (OSEM-PSF) was developed to improve the spatial resolution of reconstructed positron emission tomography (PET) images and has been reported to improve the contrast of hot spots in PET studies for oncology. However, in neuroreceptor imaging, the regional radioactivity concentration changes dynamically during the scan, and the effects of the PSF may differ among various radioligands or quantification methods. In this study, we investigated the effects of the PSF on quantification in PET studies with [(11)C]FLB 457 of dopamine D2 receptors, using both phantom and human data acquired by the Siemens Biograph 16 imaging platform. In the phantom studies, we evaluated the hot contrast recovery coefficient (HCRC) for variously sized hot spheres and the linearity between the measured and true radioactivities in OSEM-PSF images. Next, in the human studies with [(11)C]FLB 457, radioactivity concentrations and binding potentials for the cerebral cortex and thalamus were compared between images reconstructed with and without PSF. In the phantom studies, the OSEM-PSF images showed a better HCRC compared to images without PSF, and they showed a good linear correlation with true radioactivity. In the human studies, the radioactivity concentration increased especially in small regions with high accumulation of [(11)C]FLB 457 when the PSF was included. However, little difference in the binding potentials was observed for the target regions between both types of reconstructed images. In conclusion, PSF-based reconstruction reduced the spill-over phenomena in small hot regions; however, it caused no increase in the binding potentials in the [(11)C]FLB 457 studies.

  9. Single Photon Emission Local Tomography (SPELT)

    SciTech Connect

    Zeng, G.L.; Gullberg, G.T.

    1996-12-31

    Local tomography uses truncated projection data to reconstruct a region of interest, and is important in medical imaging and industrial non-destructive evaluation using micro X-ray CT. The popular filtered backprojection (FBP) algorithm does not reconstruct a reliable image, which varies with the degree and location of truncation due to its global convolution kernel. A typical local tomography method uses a second derivative local operator to replace the global convolution kernel in the filtered backprojection algorithm (LFBP). By using a local filter, the reconstructed region depends only on the local projections. The singularities (edges) are preserved, but the exact image value cannot be recovered. This paper, using the data consistency conditions, developed a pre-processing technique that uses the FBP algorithm, which outperforms direct FBP and LFBP.

  10. Single photon emission computed tomography (SPECT) in epilepsy

    SciTech Connect

    Leroy, R.F.

    1991-12-31

    Epilepsy is a common neurologic disorder which has just begun to be studied with single photon emission computerized tomography (SPECT). Epilepsy usually is studied with electroencephalographic (EEG) techniques that demonstrate the physiologic changes that occur during seizures, and with neuroimaging techniques that show the brain structures where seizures originate. Neither method alone has been adequate to describe the pathophysiology of the patient with epilepsy. EEG techniques lack anatomic sensitivity, and there are no structural abnormalities shown by neuroimaging which are specific for epilepsy. Functional imaging (FI) has developed as a physiologic tool with anatomic sensitivity, and SPECT has been promoted as a FI technique because of its potentially wide availability. However, SPECT is early in its development and its clinical utility for epilepsy still has to be demonstrated. To understand this role of SPECT, consideration must be given to the pathophysiology of epilepsy, brain physiology, types of seizure, epileptic syndromes, and the SPECT technique itself. 44 refs., 2 tabs.

  11. Psychotic reactivity to daily life stress and the dopamine system: a study combining experience sampling and [18F]fallypride positron emission tomography.

    PubMed

    Hernaus, Dennis; Collip, Dina; Lataster, Johan; Viechtbauer, Wolfgang; Myin, Erik; Ceccarini, Jenny; Van Laere, Koen; van Os, Jim; Myin-Germeys, Inez

    2015-02-01

    Stressful life events increase the risk for psychosis, and the subjective experience of stress related to daily life activities drives moment-to-moment variation in psychotic intensity. Positron emission tomography (PET) studies suggest that dopaminergic (DAergic) activity mediates the behavioral response to an experimental stressor. However, it is not known how alterations in this DAergic stress response relate to the subjective experience of stress in real life situations assessed in momentary assessment studies. This study combined [18F]fallypride PET with an Experience Sampling ambulatory assessment approach to examine the association between the prefrontal DAergic response to experimentally induced stress and real life psychotic reactivity to the subjective experience of stress in daily life. Healthy first-degree relatives of individuals with a psychotic disorder (N = 14) and healthy controls (N = 11) participated in (a) a psychosocial [18F]fallypride PET stress paradigm and (b) an experience sampling study, using a structured diary approach. Mixed multilevel random intercept models revealed that stress-induced [18F]fallypride displacement, indicative of DAergic activity, in ventromedial prefrontal cortex (VMPFC) was associated with psychotic reactivity to daily life stress in the entire sample. Lower levels of [18F]fallypride displacement to stress predicted increased psychotic reactivity to daily life stress. This study combined PET neuroimaging with real life behavioral assessments in the investigation of psychotic symptoms; we showed decreased [18F]fallypride displacement to stress in VMPFC to be associated with increased psychotic reactivity to daily life stress. The preliminary evidence in this study demonstrates that it is possible to acquire a grasp on how brain function is associated with contextualized experience, which has relevance for neuroimaging studies in general.

  12. Imaging Cellular Proliferation During Chemo-Radiotherapy: A Pilot Study of Serial {sup 18}F-FLT Positron Emission Tomography/Computed Tomography Imaging for Non-Small-Cell Lung Cancer

    SciTech Connect

    Everitt, Sarah; Hicks, Rodney J.; Ball, David; Kron, Tomas; Schneider-Kolsky, Michal; Walter, Tania; Binns, David; Mac Manus, Michael

    2009-11-15

    Purpose: To establish whether {sup 18}F-3'-deoxy-3'-fluoro-L-thymidine ({sup 18}F-FLT) can monitor changes in cellular proliferation of non-small-cell lung cancer (NSCLC) during radical chemo-radiotherapy (chemo-RT). Methods and Materials: As part of a prospective pilot study, 5 patients with locally advanced NSCLC underwent serial {sup 18}F-FLT positron emission tomography (PET)/computed tomography (CT) scans during treatment. Baseline {sup 18}F-FLT PET/CT scans were compared with routine staging {sup 18}F-FDG PET/CT scans. Two on-treatment {sup 18}F-FLT scans were performed for each patient on Days 2, 8, 15 or 29, providing a range of time points for response assessment. Results: In all 5 patients, baseline lesional uptake of {sup 18}F-FLT on PET/CT corresponded to staging {sup 18}F-FDG PET/CT abnormalities. {sup 18}F-FLT uptake in tumor was observed on five of nine (55%) on-treatment scans, on Days 2, 8 and 29, but not Day 15. A 'flare' of {sup 18}F-FLT uptake in the primary tumor of one case was observed after 2 Gy of radiation (1.22 x baseline). The remaining eight on-treatment scans demonstrated a mean reduction in {sup 18}F-FLT tumor uptake of 0.58 x baseline. A marked reduction of {sup 18}F-FLT uptake in irradiated bone marrow was observed for all cases. This reduction was observed even after only 2 Gy, and all patients demonstrated a complete absence of proliferating marrow after 10 Gy. Conclusions: This proof of concept study indicates that {sup 18}F-FLT uptake can monitor the distinctive biologic responses of epithelial cancers and highly radiosensitive normal tissue changes during radical chemo-RT. Further studies of {sup 18}F-FLT PET/CT imaging during therapy may suggest that this tracer is useful in developing response-adapted RT for NSCLC.

  13. New approaches to gastric cancer staging: Beyond endoscopic ultrasound, computed tomography and positron emission tomography

    PubMed Central

    Yoon, Hyuk; Lee, Dong Ho

    2014-01-01

    Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and 18F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years. PMID:25320516

  14. Gamma Ray Emission Tomography and Angular Correlation Measurements to Study the Distribution and Binding Site of Selenium.

    NASA Astrophysics Data System (ADS)

    Dahni, Anwar

    Available from UMI in association with The British Library. The distribution of ^ {75}Se in tissue equivalent materials was investigated employing Gamma ray Emission Topography with a rectilinear scanner utilizing NaI(Tl) and BGO detectors. The reconstructed images, using Filtered Back Projection and Iterative techniques were presented in 2D colour and 3D representations. Using a lead collimator of aperture 1.5 x 20 mm and 70 length, the distribution of selenium with variation of volume and concentration was examined and clearly seen. Several corrections such as background, scattering, attenuation compensation and X-ray characteristic suppression, were performed to improve the quality of the images which was evaluated in terms of the fidelity factor. The possibility of quantifying an image was considered with regard to spatial resolution and least detectable concentration. The spatial resolution was measured using two small vials containing the same concentration of selenium, the value obtained was the same as the width of the collimator aperture. The value of the least detectable concentration of selenium however, was difficult to find, due to the many ambiguous factors involved. The binding site of selenium which is based on quadrupole interaction with the surrounding electric field, was investigated employing Perturbed Angular Correlation (PAC) experiments using NaI(Tl) and BaF_2 detectors. Using NaI(Tl) detectors, it was difficult to observe the perturbation, due to the poor time resolution. The BaF_2 detector according to the literature has a shorter light emission decay time constant (0.6 ns), suggested that a better time resolution than that found with the NaI(Tl) detectors could be obtained. A Perturbed Angular Correlation experiment employing BaF _2 detectors and a fast-slow coincidence system was set up. The time differential PAC of selenium in solution showed an unperturbed angular correlation pattern. The main problem is the very short half life of the

  15. In Vivo Monitoring of the Antiangiogenic Effect of Neurotensin Receptor-Mediated Radiotherapy by Small-Animal Positron Emission Tomography: A Pilot Study

    PubMed Central

    Maschauer, Simone; Ruckdeschel, Tina; Tripal, Philipp; Haubner, Roland; Einsiedel, Jürgen; Hübner, Harald; Gmeiner, Peter; Kuwert, Torsten; Prante, Olaf

    2014-01-01

    The neurotensin receptor (NTS1) has emerged as an interesting target for molecular imaging and radiotherapy of NTS-positive tumors due to the overexpression in a range of tumors. The aim of this study was to develop a 177Lu-labeled NTS1 radioligand, its application for radiotherapy in a preclinical model and the imaging of therapy success by small-animal positron emission tomography (µPET) using [68Ga]DOTA-RGD as a specific tracer for imaging angiogenesis. The 177Lu-labeled peptide was subjected to studies on HT29-tumor-bearing nude mice in vivo, defining four groups of animals (single dose, two fractionated doses, four fractionated doses and sham-treated animals). Body weight and tumor diameters were determined three times per week. Up to day 28 after treatment, µPET studies were performed with [68Ga]DOTA-RGD. At days 7–10 after treatment with four fractionated doses of 11–14 MBq (each at days 0, 3, 6 and 10), the tumor growth was slightly decreased in comparison with untreated animals. Using a single high dose of 51 MBq, a significantly decreased tumor diameter of about 50% was observed with the beginning of treatment. Our preliminary PET imaging data suggested decreased tumor uptake values of [68Ga]DOTA-RGD in treated animals compared to controls at day 7 after treatment. This pilot study suggests that early PET imaging with [68Ga]DOTA-RGD in radiotherapy studies to monitor integrin expression could be a promising tool to predict therapy success in vivo. Further successive PET experiments are needed to confirm the significance and predictive value of RGD-PET for NTS-mediated radiotherapy. PMID:24743103

  16. In vivo monitoring of the antiangiogenic effect of neurotensin receptor-mediated radiotherapy by small-animal positron emission tomography: a pilot study.

    PubMed

    Maschauer, Simone; Ruckdeschel, Tina; Tripal, Philipp; Haubner, Roland; Einsiedel, Jürgen; Hübner, Harald; Gmeiner, Peter; Kuwert, Torsten; Prante, Olaf

    2014-01-01

    The neurotensin receptor (NTS1) has emerged as an interesting target for molecular imaging and radiotherapy of NTS-positive tumors due to the overexpression in a range of tumors. The aim of this study was to develop a 177Lu-labeled NTS1 radioligand, its application for radiotherapy in a preclinical model and the imaging of therapy success by small-animal positron emission tomography (µPET) using [68Ga]DOTA-RGD as a specific tracer for imaging angiogenesis. The 177Lu-labeled peptide was subjected to studies on HT29-tumor-bearing nude mice in vivo, defining four groups of animals (single dose, two fractionated doses, four fractionated doses and sham-treated animals). Body weight and tumor diameters were determined three times per week. Up to day 28 after treatment, µPET studies were performed with [68Ga]DOTA-RGD. At days 7-10 after treatment with four fractionated doses of 11-14 MBq (each at days 0, 3, 6 and 10), the tumor growth was slightly decreased in comparison with untreated animals. Using a single high dose of 51 MBq, a significantly decreased tumor diameter of about 50% was observed with the beginning of treatment. Our preliminary PET imaging data suggested decreased tumor uptake values of [68Ga]DOTA-RGD in treated animals compared to controls at day 7 after treatment. This pilot study suggests that early PET imaging with [68Ga]DOTA-RGD in radiotherapy studies to monitor integrin expression could be a promising tool to predict therapy success in vivo. Further successive PET experiments are needed to confirm the significance and predictive value of RGD-PET for NTS-mediated radiotherapy. PMID:24743103

  17. Respiratory motion correction in emission tomography image reconstruction.

    PubMed

    Reyes, Mauricio; Malandain, Grégoire; Koulibaly, Pierre Malick; González Ballester, Miguel A; Darcourt, Jacques

    2005-01-01

    In Emission Tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations and imprecise diagnosis. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested with improvements over the spatial activity distribution in lungs lesions, but with the disadvantages of requiring additional instrumentation or discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory motion correction directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the Maximum Likelihood Expectation Maximization (MLEM) algorithm that includes a respiratory motion model, which takes into account the displacements and volume deformations produced by the respiratory motion during the data acquisition process. We present results from synthetic simulations incorporating real respiratory motion as well as from phantom and patient data.

  18. Brain abnormalities in murderers indicated by positron emission tomography.

    PubMed

    Raine, A; Buchsbaum, M; LaCasse, L

    1997-09-15

    Murderers pleading not guilty by reason of insanity (NGRI) are thought to have brain dysfunction, but there have been no previous studies reporting direct measures of both cortical and subcortical brain functioning in this specific group. Positron emission tomography brain imaging using a continuous performance challenge task was conducted on 41 murderers pleading not guilty by reason of insanity and 41 age- and sex-matched controls. Murderers were characterized by reduced glucose metabolism in the prefrontal cortex, superior parietal gyrus, left angular gyrus, and the corpus callosum, while abnormal asymmetries of activity (left hemisphere lower than right) were also found in the amygdala, thalamus, and medial temporal lobe. These preliminary findings provide initial indications of a network of abnormal cortical and subcortical brain processes that may predispose to violence in murderers pleading NGRI.

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

    SciTech Connect

    Schwartz, J.M.; Baxter, L.R. Jr.; Mazziotta, J.C.; Gerner, R.H.; Phelps, M.E.

    1987-09-11

    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.

  20. Chelators for copper radionuclides in positron emission tomography radiopharmaceuticals†

    PubMed Central

    Cai, Zhengxin; Anderson, Carolyn J.

    2014-01-01

    The development of chelating agents for copper radionuclides in positron emission tomography radiopharmaceuticals has been a highly active and important area of study in recent years. The rapid evolution of chelators has resulted in highly specific copper chelators that can be readily conjugated to biomolecules and efficiently radiolabeled to form stable complexes in vivo. Chelators are not only designed for conjugation to monovalent biomolecules but also for incorporation into multivalent targeting ligands such as theranostic nanoparticles. These advancements have strengthened the role of copper radionuclides in the fields of nuclear medicine and molecular imaging. This review emphasizes developments of new copper chelators that have most greatly advanced the field of copper-based radiopharmaceuticals over the past 5 years. PMID:24347474

  1. Positron emission tomography for the evaluation and treatment of cardiomyopathy.

    PubMed

    Shah, Palak; Choi, Brian G; Mazhari, Ramesh

    2011-06-01

    Congestive heart failure accounts for tremendous morbidity and mortality worldwide. There are numerous causes of cardiomyopathy, the most common of which is coronary artery disease. Positron emission tomography (PET) has an established and expanding role in the evaluation of patients with cardiomyopathy. The specific application of PET to hypertrophic cardiomyopathy, cardiac sarcoidosis, and diabetic cardiomyopathy has been studied extensively and promises to be a useful tool for managing these patients. Furthermore, evaluating the efficacy of standard treatments for congestive heart failure is important as health care costs continue to rise. Recently, there have been significant developments in the field of cardiovascular stem cell research. Familiarity with the mechanisms by which stem cells benefit patients with cardiovascular disease is the key to understanding these advances. Molecular imaging techniques including PET/CT imaging play an important role in monitoring stem cell therapy in both animals and humans. These noninvasive imaging techniques will be highlighted in this paper.

  2. [Positron emission tomography (PET) in malignant ovarian tumors].

    PubMed

    Fularz, Maciej; Adamiak, Paulina; Czepczyński, Rafał; Jarzabek-Bielecka, Grazyna; Kedzia, Witold; Ruchała, Marek

    2013-08-01

    Accessibility of positron emission tomography integrated with computed tomography (PET/CT) has improved significantly in recent years. PET/CT with the use of 18F-deoxyglucose (FDG) is widely used in patients with ovarian malignancies at different stages of the management. FDG PET/CT shows high diagnostic accuracy in the differentiation of benign and malignant ovarian lesions with the exception of borderline tumors that may cause false negative results. Moreover FDG PET/CT is used in some centers for preoperative staging and determining the prognosis of ovarian cancer However further studies including larger groups of patients are needed to confirm the applicability of FDG PET/CT in case of the two abovementioned indications. Until now, the best documented indication for FDG PET/ CT in patients with ovarian cancer has been the detection of recurrence, especially in subjects with elevated CA 125 marker and negative results of other imaging techniques. This review focuses on the applicability of PET with the use of FDG in ovarian malignancies and points out to the limitations of this method.

  3. Positron Emission Tomography: Human Brain Function and Biochemistry.

    ERIC Educational Resources Information Center

    Phelps, Michael E.; Mazziotta, John C.

    1985-01-01

    Describes the method, present status, and application of positron emission tomography (PET), an analytical imaging technique for "in vivo" measurements of the anatomical distribution and rates of specific biochemical reactions. Measurements and image dynamic biochemistry link basic and clinical neurosciences with clinical findings suggesting…

  4. Recent Developments in Positron Emission Tomography (PET) Instrumentation

    DOE R&D Accomplishments Database

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

    1986-04-01

    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.

  5. Risky Decision-Making and Ventral Striatal Dopamine Responses to Amphetamine: A Positron Emission Tomography [11C] Raclopride Study in Healthy Adults

    PubMed Central

    Oswald, Lynn M.; Wand, Gary S.; Wong, Dean F.; Brown, Clayton H.; Kuwabara, Hiroto; Brašić, James R.

    2015-01-01

    Recent functional magnetic resonance imaging (fMRI) studies have provided compelling evidence that corticolimbic brain regions are integrally involved in human decision-making. Although much less is known about molecular mechanisms, there is growing evidence that the mesolimbic dopamine (DA) neurotransmitter system may be an important neural substrate. Thus far, direct examination of DA signaling in human risk-taking has centered onl gambling disorder. Findings from several positron emission tomography (PET) studies suggest that dysfunctions in mesolimbic DA circuits may play an important role in gambling behavior. Nevertheless, interpretation of these findings is currently hampered by a need for better understanding of how individual differences in regional DA function influence normative decision-making in humans. To further our understanding of these processes, we used [11C]raclopride PET to examine associations between ventral striatal (VS) DA responses to amphetamine (AMPH) and risky decision-making in a sample of healthy young adults with no history of psychiatric disorder, Forty-five male and female subjects, ages 18–29 years, completed a computerized version of the IOWA Gambling Task. Participants then underwent two 90-minute PET studies with high specific activity [11C]raclopride. The first scan was preceded by intravenous saline; the second, by intravenous AMPH (0.3 mg/kg). Findings of primary analyses showed that less advantageous decision-making was associated with greater right VS DA release; the relationship did not differ as a function of gender. No associations were observed between risk-taking and left VS DA release or baseline D2/D3 receptor availability in either hemisphere. Overall, the results support notions that variability in striatal DA function may mediate inter-individual differences in risky decision-making in healthy adults, further suggesting that hypersensitive DA circuits may represent a risk pathway in this population. PMID

  6. The influence of tumor oxygenation on 18F-FDG (Fluorine-18 Deoxyglucose) uptake: A mouse study using positron emission tomography (PET)

    PubMed Central

    Chan, Linda W; Hapdey, Sebastien; English, Sean; Seidel, Jurgen; Carson, Joann; Sowers, Anastasia L; Krishna, Murali C; Green, Michael V; Mitchell, James B; Bacharach, Stephen L

    2006-01-01

    Background This study investigated whether changing a tumor's oxygenation would alter tumor metabolism, and thus uptake of 18F-FDG (fluorine-18 deoxyglucose), a marker for glucose metabolism using positron emission tomography (PET). Results Tumor-bearing mice (squamous cell carcinoma) maintained at 37°C were studied while breathing either normal air or carbogen (95% O2, 5% CO2), known to significantly oxygenate tumors. Tumor activity was measured within an automatically determined volume of interest (VOI). Activity was corrected for the arterial input function as estimated from image and blood-derived data. Tumor FDG uptake was initially evaluated for tumor-bearing animals breathing only air (2 animals) or only carbogen (2 animals). Subsequently, 5 animals were studied using two sequential 18F-FDG injections administered to the same tumor-bearing mouse, 60 min apart; the first injection on one gas (air or carbogen) and the second on the other gas. When examining the entire tumor VOI, there was no significant difference of 18F-FDG uptake between mice breathing either air or carbogen (i.e. air/carbogen ratio near unity). However, when only the highest 18F-FDG uptake regions of the tumor were considered (small VOIs), there was a modest (21%), but significant increase in the air/carbogen ratio suggesting that in these potentially most hypoxic regions of the tumor, 18F-FDG uptake and hence glucose metabolism, may be reduced by increasing tumor oxygenation. Conclusion Tumor 18F-FDG uptake may be reduced by increases in tumor oxygenation and thus may provide a means to further enhance 18F-FDG functional imaging. PMID:16722588

  7. Risky decision-making and ventral striatal dopamine responses to amphetamine: a positron emission tomography [(11)C]raclopride study in healthy adults.

    PubMed

    Oswald, Lynn M; Wand, Gary S; Wong, Dean F; Brown, Clayton H; Kuwabara, Hiroto; Brašić, James R

    2015-06-01

    Recent functional magnetic resonance imaging (fMRI) studies have provided compelling evidence that corticolimbic brain regions are integrally involved in human decision-making. Although much less is known about molecular mechanisms, there is growing evidence that the mesolimbic dopamine (DA) neurotransmitter system may be an important neural substrate. Thus far, direct examination of DA signaling in human risk-taking has centered on gambling disorder. Findings from several positron emission tomography (PET) studies suggest that dysfunctions in mesolimbic DA circuits may play an important role in gambling behavior. Nevertheless, interpretation of these findings is currently hampered by a need for better understanding of how individual differences in regional DA function influence normative decision-making in humans. To further our understanding of these processes, we used [(11)C]raclopride PET to examine associations between ventral striatal (VS) DA responses to amphetamine (AMPH) and risky decision-making in a sample of healthy young adults with no history of psychiatric disorder, Forty-five male and female subjects, ages 18-29 years, completed a computerized version of the Iowa Gambling Task. Participants then underwent two 90-minute PET studies with high specific activity [(11)C]raclopride. The first scan was preceded by intravenous saline; the second, by intravenous AMPH (0.3mg/kg). Findings of primary analyses showed that less advantageous decision-making was associated with greater right VS DA release; the relationship did not differ as a function of gender. No associations were observed between risk-taking and left VS DA release or baseline D2/D3 receptor availability in either hemisphere. Overall, the results support notions that variability in striatal DA function may mediate inter-individual differences in risky decision-making in healthy adults, further suggesting that hypersensitive DA circuits may represent a risk pathway in this population. PMID

  8. Depressed glucose consumption at reperfusion following brain ischemia does not correlate with mitochondrial dysfunction and development of infarction: an in vivo positron emission tomography study.

    PubMed

    Martín, Abraham; Rojas, Santiago; Pareto, Deborah; Santalucia, Tomàs; Millán, Olga; Abasolo, Ibane; Gómez, Vanessa; Llop, Jordi; Gispert, Joan D; Falcon, Carles; Bargalló, Núria; Planas, Anna M

    2009-05-01

    Glucose consumption is severely depressed in the ischemic core, whereas it is maintained or even increased in penumbral regions during ischemia. Conversely, glucose utilization is severely reduced early after reperfusion in spite that glucose and oxygen are available. Experimental studies suggest that glucose hypometabolism might be an early predictor of brain infarction. However, the relationship between early glucose hypometabolism with later development of infarction remains to be further studied in the same subjects. Here, glucose consumption was assessed in vivo by positron emission tomography (PET) with (18)F-fluorodeoxyglucose ((18)F-FDG) in a rat model of ischemia/reperfusion. Perfusion was evaluated by PET with (13)NH(3) during and after 2-hour (h) middle cerebral artery occlusion, and (18)F-FDG was given after 2h of reperfusion. Brain infarction was evaluated at 24h. Mitochondrial oxygen consumption was examined ex vivo using a biochemical method. Cortical (18)F-FDG uptake was reduced by 45% and 25% in the ischemic core and periphery, respectively. However, substantial alteration of mitochondrial respiration was not apparent until 24h, suggesting that mitochondria retained the ability to consume oxygen early after reperfusion. These results show reduced glucose use at early reperfusion in regions that will later develop infarction and, to a lesser extent, in adjacent regions. Depressed glucose metabolism in the ischemic core might be attributable to reduced metabolic requirement due to irreversible cellular injury. However, reduced glucose metabolism in peripheral regions suggests either an impairment of glycolysis or reduced glucose demand. Thus, our study supports that glycolytic depression early after reperfusion is not always related to subsequent development of infarction.

  9. Distinguishing tumor recurrence from irradiation sequelae with positron emission tomography in patients treated for larynx cancer

    SciTech Connect

    Greven, K.M.; Williams, D.W. III; Keyes, J.W. Jr.; McGuirt, W.F.; Harkness, B.A.; Watson, N.E. Jr.; Raben, M.; Frazier, L.C.; Geisinger, K.R.; Capellari, J.O.

    1994-07-01

    Distinguishing persistent or recurrent tumor from postradiation edema, or soft tissue/cartilage necrosis in patients treated for carcinoma of the larynx can be difficult. Because recurrent tumor is often submucosal, multiple deep biopsies may be necessary before a diagnosis can be established. Positron emission tomography with 18F-2-fluro-2-deoxglucose (FDG) was studied for its ability to aid in this problem. Positron emission tomography (18FDG) scans were performed on 11 patients who were suspected of having persistent or recurrent tumor after radiation treatment for carcinoma of the larynx. Patients underwent thorough history and physical examinations, scans with computerized tomography, and pathologic evaluation when indicated. Standard uptake values were used to quantitate the FDG uptake in the larynx. The time between completion of radiation treatment and positron emission tomography examination ranged from 2 to 26 months with a median of 6 months. Ten patients underwent computed tomography (CT) of the larynx, which revealed edema of the larynx (six patients), glottic mass (four patients), and cervical nodes (one patient). Positron emission tomography scans revealed increased FDG uptake in the larynx in five patients and laryngectomy confirmed the presence of carcinoma in these patients. Five patients had positron emission tomography results consistent with normal tissue changes in the larynx, and one patient had increased FDG uptake in neck nodes. This patient underwent laryngectomy, and no cancer was found in the primary site, but nodes were pathologically positive. One patient had slightly elevated FDG uptake and negative biopsy results. The remaining patients have been followed for 11 to 14 months since their positron emission studies and their examinations have remained stable. In patients without tumor, average standard uptake values of the larynx ranged from 2.4 to 4.7, and in patients with tumor, the range was 4.9 to 10.7. 18 refs., 3 figs., 1 tab.

  10. Integrated telemedicine applications and services for oncological positron emission tomography.

    PubMed

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

    2006-01-01

    TENPET (Trans European Network for Positron Emission Tomography) aims to evaluate the provision of integrated teleconsultation and intelligent computer supported cooperative work services for clinical positron emission tomography (PET) in Europe at its current stage, as it is a multi-centre project financially supported by the European Commission (Information Society, eTEN Program). It addresses technological challenges by linking PET centres and developing supporting services that permit remote consultation between professionals in the field. The technological platform (CE-marked) runs on Win2000/NT/XP systems and incorporates advanced techniques for image visualization, analysis and fusion, as well as for interactive communication and message handling for off-line communications. Four PET Centres from Spain, France and Germany participate to the pilot system trials. The performance evaluation of the system is carried out via log files and user-filled questionnaires on the frequency of the teleconsultations, their duration and efficacy, quality of the images received, user satisfaction, as well as on privacy, ethical and security issues. TENPET promotes the co-operation and improved communication between PET practitioners that are miles away from their peers or on mobile units, offering options for second opinion and training and permitting physicians to remotely consult patient data if they are away from their centre. It is expected that TENPET will have a significant impact in the development of new skills by PET professionals and will support the establishment of peripheral PET units. To our knowledge, TENPET is the first telemedicine service specifically designed for oncological PET. This report presents the technical innovations incorporated in the TENPET platform and the initial pilot studies at real and diverse clinical environments in the field of oncology.

  11. The role of metabotropic glutamate receptor 5 in the pathogenesis of mood disorders and addiction: combining preclinical evidence with human Positron Emission Tomography (PET) studies

    PubMed Central

    Terbeck, Sylvia; Akkus, Funda; Chesterman, Laurence P.; Hasler, Gregor

    2015-01-01

    In the present review, we deliver an overview of the involvement of metabotropic glutamate receptor 5 (mGluR5) activity and density in pathological anxiety, mood disorders and addiction. Specifically, we will describe mGluR5 studies in humans that employed Positron Emission Tomography (PET) and combined the findings with preclinical animal research. This combined view of different methodological approaches—from basic neurobiological approaches to human studies—might give a more comprehensive and clinically relevant view of mGluR5 function in mental health than the view on preclinical data alone. We will also review the current research data on mGluR5 along the Research Domain Criteria (RDoC). Firstly, we found evidence of abnormal glutamate activity related to the positive and negative valence systems, which would suggest that antagonistic mGluR5 intervention has prominent anti-addictive, anti-depressive and anxiolytic effects. Secondly, there is evidence that mGluR5 plays an important role in systems for social functioning and the response to social stress. Finally, mGluR5's important role in sleep homeostasis suggests that this glutamate receptor may play an important role in RDoC's arousal and modulatory systems domain. Glutamate was previously mostly investigated in non-human studies, however initial human clinical PET research now also supports the hypothesis that, by mediating brain excitability, neuroplasticity and social cognition, abnormal metabotropic glutamate activity might predispose individuals to a broad range of psychiatric problems. PMID:25852460

  12. Pharmacokinetic modeling of P-glycoprotein function at the rat and human blood–brain barriers studied with (R)-[11C]verapamil positron emission tomography

    PubMed Central

    2012-01-01

    Background This study investigated the influence of P-glycoprotein (P-gp) inhibitor tariquidar on the pharmacokinetics of P-gp substrate radiotracer (R)-[11C]verapamil in plasma and brain of rats and humans by means of positron emission tomography (PET). Methods Data obtained from a preclinical and clinical study, in which paired (R)-[11C]verapamil PET scans were performed before, during, and after tariquidar administration, were analyzed using nonlinear mixed effects (NLME) modeling. Administration of tariquidar was included as a covariate on the influx and efflux parameters (Qin and Qout) in order to investigate if tariquidar increased influx or decreased outflux of radiotracer across the blood–brain barrier (BBB). Additionally, the influence of pilocarpine-induced status epilepticus (SE) was tested on all model parameters, and the brain-to-plasma partition coefficient (VT-NLME) was calculated. Results Our model indicated that tariquidar enhances brain uptake of (R)-[11C]verapamil by decreasing Qout. The reduction in Qout in rats during and immediately after tariquidar administration (sevenfold) was more pronounced than in the second PET scan acquired 2 h after tariquidar administration (fivefold). The effect of tariquidar on Qout in humans was apparent during and immediately after tariquidar administration (twofold reduction in Qout) but was negligible in the second PET scan. SE was found to influence the pharmacological volume of distribution of the central brain compartment Vbr1. Tariquidar treatment lead to an increase in VT-NLME, and pilocarpine-induced SE lead to increased (R)-[11C]verapamil distribution to the peripheral brain compartment. Conclusions Using NLME modeling, we were able to provide mechanistic insight into the effects of tariquidar and SE on (R)-[11C]verapamil transport across the BBB in control and 48 h post SE rats as well as in humans. PMID:23072492

  13. Principal component analysis with pre-normalization improves the signal-to-noise ratio and image quality in positron emission tomography studies of amyloid deposits in Alzheimer's disease

    NASA Astrophysics Data System (ADS)

    Razifar, Pasha; Engler, Henry; Blomquist, Gunnar; Ringheim, Anna; Estrada, Sergio; Långström, Bengt; Bergström, Mats

    2009-06-01

    This study introduces a new approach for the application of principal component analysis (PCA) with pre-normalization on dynamic positron emission tomography (PET) images. These images are generated using the amyloid imaging agent N-methyl [11C]2-(4'-methylaminophenyl)-6-hydroxy-benzothiazole ([11C]PIB) in patients with Alzheimer's disease (AD) and healthy volunteers (HVs). The aim was to introduce a method which, by using the whole dataset and without assuming a specific kinetic model, could generate images with improved signal-to-noise and detect, extract and illustrate changes in kinetic behavior between different regions in the brain. Eight AD patients and eight HVs from a previously published study with [11C]PIB were used. The approach includes enhancement of brain regions where the kinetics of the radiotracer are different from what is seen in the reference region, pre-normalization for differences in noise levels and removal of negative values. This is followed by slice-wise application of PCA (SW-PCA) on the dynamic PET images. Results obtained using the new approach were compared with results obtained using reference Patlak and summed images. The new approach generated images with good quality in which cortical brain regions in AD patients showed high uptake, compared to cerebellum and white matter. Cortical structures in HVs showed low uptake as expected and in good agreement with data generated using kinetic modeling. The introduced approach generated images with enhanced contrast and improved signal-to-noise ratio (SNR) and discrimination power (DP) compared to summed images and parametric images. This method is expected to be an important clinical tool in the diagnosis and differential diagnosis of dementia.

  14. Principal component analysis with pre-normalization improves the signal-to-noise ratio and image quality in positron emission tomography studies of amyloid deposits in Alzheimer's disease.

    PubMed

    Razifar, Pasha; Engler, Henry; Blomquist, Gunnar; Ringheim, Anna; Estrada, Sergio; Långström, Bengt; Bergström, Mats

    2009-06-01

    This study introduces a new approach for the application of principal component analysis (PCA) with pre-normalization on dynamic positron emission tomography (PET) images. These images are generated using the amyloid imaging agent N-methyl [(11)C]2-(4'-methylaminophenyl)-6-hydroxy-benzothiazole ([(11)C]PIB) in patients with Alzheimer's disease (AD) and healthy volunteers (HVs). The aim was to introduce a method which, by using the whole dataset and without assuming a specific kinetic model, could generate images with improved signal-to-noise and detect, extract and illustrate changes in kinetic behavior between different regions in the brain. Eight AD patients and eight HVs from a previously published study with [(11)C]PIB were used. The approach includes enhancement of brain regions where the kinetics of the radiotracer are different from what is seen in the reference region, pre-normalization for differences in noise levels and removal of negative values. This is followed by slice-wise application of PCA (SW-PCA) on the dynamic PET images. Results obtained using the new approach were compared with results obtained using reference Patlak and summed images. The new approach generated images with good quality in which cortical brain regions in AD patients showed high uptake, compared to cerebellum and white matter. Cortical structures in HVs showed low uptake as expected and in good agreement with data generated using kinetic modeling. The introduced approach generated images with enhanced contrast and improved signal-to-noise ratio (SNR) and discrimination power (DP) compared to summed images and parametric images. This method is expected to be an important clinical tool in the diagnosis and differential diagnosis of dementia.

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

    PubMed Central

    Papin-Michault, Caroline; Bonnetaud, Christelle; Dufour, Maxime; Almairac, Fabien; Coutts, Mickael; Patouraux, Stéphanie; Virolle, Thierry; Darcourt, Jacques; Burel-Vandenbos, Fanny

    2016-01-01

    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. PMID:27276226

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

    SciTech Connect

    Llacer, J.; Veklerov, E.; Nolan, D. ); Grafton, S.T.; Mazziotta, J.C.; Hawkins, R.A.; Hoh, C.K.; Hoffman, E.J. )

    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. The Effect of Delayed Auditory Feedback on Activity in the Temporal Lobe while Speaking: A Positron Emission Tomography Study

    ERIC Educational Resources Information Center

    Takaso, Hideki; Eisner, Frank; Wise, Richard J. S.; Scott, Sophie K.

    2010-01-01

    Purpose: Delayed auditory feedback is a technique that can improve fluency in stutterers, while disrupting fluency in many nonstuttering individuals. The aim of this study was to determine the neural basis for the detection of and compensation for such a delay, and the effects of increases in the delay duration. Method: Positron emission…

  18. New techniques for positron emission tomography in the study of human neurological disorders. Progress report, June 1990--June 1993

    SciTech Connect

    Kuhl, D.E.

    1993-06-01

    This progress report describes accomplishments of four programs. The four programs are entitled (1) Faster,simpler processing of positron-computing precursors: New physicochemical approaches, (2) Novel solid phase reagents and methods to improve radiosynthesis and isotope production, (3) Quantitative evaluation of the extraction of information from PET images, and (4) Optimization of tracer kinetic methods for radioligand studies in PET.

  19. Imaging and analysis of thin structures using positron emission tomography: Thin phantoms and in vivo tobacco leaves study.

    PubMed

    Partelová, Denisa; Horník, Miroslav; Lesný, Juraj; Rajec, Pavol; Kováč, Peter; Hostin, Stanislav

    2016-09-01

    In this work, a novel approach utilizing the designed phantoms imitating the plant tissues was applied for the evaluation of the relationships between the parameters of the prepared phantoms and/or quantitative variables obtained within the PET analysis. The microPET system developed for animal objects and approaches used made it possible to obtain the quantitative data in the form of (18)F radioactivity as well as the glucose (in µg) accumulated in leaf tissues within the dynamic in vivo study. PMID:27344004

  20. Neural correlates of intelligibility in speech investigated with noise vocoded speech--a positron emission tomography study.

    PubMed

    Scott, Sophie K; Rosen, Stuart; Lang, Harriet; Wise, Richard J S

    2006-08-01

    Functional imaging studies of speech perception in the human brain have identified a key role for auditory association areas in the temporal lobes (bilateral superior temporal gyri and sulci) in the perceptual processing of the speech signal. This is extended to suggest some functional specialization within this bilateral system, with a particular role for the left anterior superior temporal sulcus (STS) in processing intelligible speech. In the current study, noise-vocoded speech was used to vary the intelligibility of speech parametrically. This replicated the finding of a selective response to intelligibility in speech in the left anterior superior temporal sulcus, in contrast to the posterior superior temporal sulcus, which showed a response profile insensitive to the degree of intelligibility. These results are related to theories of functional organization in the human auditory system, which have indicated that there are separate processing streams, with different functional roles, running anterior and posterior to primary auditory cortex. Specifically, it is suggested that an anterior stream processing intelligibility can be distinguished from a posterior stream associated with transient representations, important in spoken repetition and working memory. PMID:16938993

  1. [(11)C]Raclopride binding in the striatum of minimally restrained and free-walking awake mice in a positron emission tomography study.

    PubMed

    Takuwa, Hiroyuki; Maeda, Jun; Ikoma, Yoko; Tokunaga, Masaki; Wakizaka, Hidekatsu; Uchida, Shouko; Kanno, Iwao; Taniguchi, Junko; Ito, Hiroshi; Higuchi, Makoto

    2015-12-01

    Anesthesia and restraint stress have profound impacts on brain functions, including neural activity and cerebrovascular function, possibly influencing functional and neurochemical positron emission tomography (PET) imaging data. For circumventing this effect, we developed an experimental system enabling PET imaging of free-walking awake mice with minimal restraints by fixing the head to a holder. The applicability of this system was investigated by performing PET imaging of D2 dopamine receptors with [(11)C]raclopride under the following three different conditions: (1) free-walking awake state; (2) 1.5% isoflurane anesthesia; and (3) whole-body restraint without anesthesia. [(11)C]raclopride binding potential (BP(ND)) values under isoflurane anesthesia and restrained awake state were significantly lower than under free-walking awake state (P < 0.01). Heart rates in restrained awake mice were significantly higher than those in free-walking awake mice (P < 0.01), suggesting that free-walking awake state minimized restraint stress during the PET scan. [(11)C] raclopride-PET with methamphetamine (METH) injection was also performed in awake and anesthetized mice. METH-induced reduction of [(11)C]raclopride BP(ND) in anesthetized mice showed a trend to be less than that in free-walking awake mice, implying that pharmacological modulation of dopaminergic transmissions could be sensitively captured by PET imaging of free-walking awake mice. We concluded that our system is of utility as an in vivo assaying platform for studies of brain functions and neurotransmission elements in small animals, such as those modeling neuropsychiatric disorders.

  2. Heightened D3 Dopamine Receptor Levels in Cocaine Dependence and Contributions to the Addiction Behavioral Phenotype: A Positron Emission Tomography Study with [11C]-(+)-PHNO

    PubMed Central

    Payer, Doris E; Behzadi, Arian; Kish, Stephen J; Houle, Sylvain; Wilson, Alan A; Rusjan, Pablo M; Tong, Junchao; Selby, Peter; George, Tony P; McCluskey, Tina; Boileau, Isabelle

    2014-01-01

    The dopamine system is a primary treatment target for cocaine dependence (CD), but research on dopaminergic abnormalities (eg, D2 receptor system deficiencies) has so far failed to translate into effective treatment strategies. The D3 receptor system has recently attracted considerable clinical interest, and D3 antagonism is now under investigation as a novel avenue for addiction treatment. The objective here was to evaluate the status and behavioral relevance of the D3 receptor system in CD, using the positron emission tomography (PET) radiotracer [11C]-(+)-PHNO. Fifteen CD subjects (many actively using, but all abstinent 7–240 days on scan day) and fifteen matched healthy control (HC) subjects completed two PET scans: one with [11C]-(+)-PHNO to assess D3 receptor binding (BPND; calculated regionally using the simplified reference tissue model), and for comparison, a second scan with [11C]raclopride to assess D2/3 binding. CD subjects also completed a behavioral battery to characterize the addiction behavioral phenotype. CD subjects showed higher [11C]-(+)-PHNO BPND than HC in the substantia nigra, which correlated with behavioral impulsiveness and risky decision making. In contrast, [11C]raclopride BPND was lower across the striatum in CD, consistent with previous literature in ⩾2 week abstinence. The data suggest that in contrast to a D2 deficiency, CD individuals may have heightened D3 receptor levels, which could contribute to addiction-relevant traits. D3 upregulation is emerging as a biomarker in preclinical models of addiction, and human PET studies of this receptor system can help guide novel pharmacological strategies for treatment. PMID:23921256

  3. Modulation of P-glycoprotein at the Human Blood-Brain Barrier by Quinidine or Rifampin Treatment: A Positron Emission Tomography Imaging Study.

    PubMed

    Liu, Li; Collier, Ann C; Link, Jeanne M; Domino, Karen B; Mankoff, David A; Eary, Janet F; Spiekerman, Charles F; Hsiao, Peng; Deo, Anand K; Unadkat, Jashvant D

    2015-11-01

    Permeability-glycoprotein (P-glycoprotein, P-gp), an efflux transporter at the human blood-brain barrier (BBB), is a significant obstacle to central nervous system (CNS) delivery of P-gp substrate drugs. Using positron emission tomography imaging, we investigated P-gp modulation at the human BBB by an approved P-gp inhibitor, quinidine, or the P-gp inducer, rifampin. Cerebral blood flow (CBF) and BBB P-gp activity were respectively measured by administration of (15)O-water followed by (11)C-verapamil. In a crossover design, healthy volunteers received quinidine and 11-29 days of rifampin treatment during different study periods. CBF and P-gp activity was measured in the absence (control; prior to quinidine treatment) and presence of P-gp modulation. At clinically relevant quinidine plasma concentrations, P-gp inhibition resulted in a 60% increase in (11)C-radioactivity distribution across the human BBB as measured by the brain extraction ratio (ER) of (11)C-radioactivity. Furthermore, the magnitude of BBB P-gp inhibition by quinidine was successfully predicted by a combination of in vitro and macaque data, but not by rat data. Although our findings demonstrated that quinidine did not completely inhibit P-gp at the human BBB, it has the potential to produce clinically significant CNS drug interactions with P-gp substrate drugs that exhibit a narrow therapeutic window and are significantly excluded from the brain by P-gp. Rifampin treatment induced systemic CYP3A metabolism of (11)C-verapamil; however, it reduced the ER by 6%. Therefore, we conclude that rifampin, at its usual clinical dose, cannot be used to induce P-gp at the human BBB to a clinically meaningful extent and is unlikely to cause inadvertent BBB-inductive drug interactions. PMID:26354948

  4. The antiepileptic drug mephobarbital is not transported by P-glycoprotein or multidrug resistance protein 1 at the blood-brain barrier: a positron emission tomography study

    PubMed Central

    Mairinger, Severin; Bankstahl, Jens P.; Kuntner, Claudia; Römermann, Kerstin; Bankstahl, Marion; Wanek, Thomas; Stanek, Johann; Löscher, Wolfgang; Müller, Markus; Erker, Thomas; Langer, Oliver

    2013-01-01

    Summary Aim of this study was to determine whether the carbon-11-labelled antiepileptic drug [11C]mephobarbital is a substrate of P-glycoprotein (Pgp) and can be used to assess Pgp function at the blood-brain barrier (BBB) with positron emission tomography (PET). We performed paired PET scans in rats, wild-type (FVB) and Mdr1a/b(−/−) mice, before and after intravenous administration of the Pgp inhibitor tariquidar (15 mg/kg). Brain-to-blood AUC0-60 ratios in rats and brain AUC0-60 values of [11C]mephobarbital in wild-type and Mdr1a/b(−/−) mice were similar in scan 1 and scan 2, respectively, suggesting that in vivo brain distribution of [11C]mephobarbital is not influenced by Pgp efflux. Absence of Pgp transport was confirmed in vitro by performing concentration equilibrium transport assay in cell lines transfected with MDR1 or Mdr1a. PET experiments in wild-type mice, with and without pretreatment with the multidrug resistance protein (MRP) inhibitor MK571 (20 mg/kg), and in Mrp1(−/−) mice suggested that [11C]mephobarbital is also not transported by MRPs at the murine BBB, which was also supported by in vitro transport experiments using human MRP1-transfected cells. Our results are surprising as phenobarbital, the N-desmethyl derivative of mephobarbital, has been shown to be a substrate of Pgp, which suggests that N-methylation abolishes Pgp affinity of barbiturates. PMID:22342565

  5. A study on statistically reliable and computationally efficient algorithms for generating local cerebral blood flow parametric images with positron emission tomography

    SciTech Connect

    Feng, Dagan; Wang, Zhizhong . Basser Dept. of Computer Science); Huang, Sung Cheng . Dept. of Radiological Sciences)

    1993-06-01

    With the advent of positron emission tomography (PET), a variety of techniques have been developed to measure local cerebral blood flow (LCBF) noninvasively in humans. It is essential that the techniques developed should be statistically reliable and computationally efficient. A potential class of techniques, which includes linear least squares (LS), linear weighted least squares (WLS), linear generalized least squares (GLS), and linear generalized weighted least squares (GWLS), is proposed. The statistical characteristics of the new methods were examined by computer simulation. The authors present a comparison of these four methods with two other rapid estimation techniques developed by Huang et al. and Alpert, and two classical methods, the unweighted and weighted nonlinear least squares regression which are supposed to have optimal statistical properties. The results show that the new methods can take full advantage of the contribution from the fine temporal sampling data of modern tomographs, and thus provide statistically reliable estimates that are comparable to those obtained from nonlinear least squares regression. The new methods also have high computational efficiency, and the parameters can be estimated directly from operational equations in one single step. Therefore, they can potentially be used in image-wide estimation of local cerebral blood flow and distribution volume with positron emission tomography.

  6. A novel phantom design for emission tomography enabling scatter- and attenuation-"free" single-photon emission tomography imaging.

    PubMed

    Larsson, S A; Jonsson, C; Pagani, M; Johansson, L; Jacobsson, H

    2000-02-01

    A newly designed technique for experimental single-photon emission tomography (SPET) and positron emission tomography (PET) data acquisition with minor disturbing effects from scatter and attenuation has been developed. In principle, the method is based on discrete sampling of the radioactivity distribution in 3D objects by means of equidistant 2D planes. The starting point is a set of digitised 2D sections representing the radioactivity distribution of the 3D object. Having a radioactivity-related grey scale, the 2D images are printed on paper sheets using radioactive ink. The radioactive sheets can be shaped to the outline of the object and stacked into a 3D structure with air or some arbitrary dense material in between. For this work, equidistantly spaced transverse images of a uniform cylindrical phantom and of the digitised Hoffman rCBF phantom were selected and printed out on paper sheets. The uniform radioactivity sheets were imaged on the surface of a low-energy ultra-high-resolution collimator (4 mm full-width at half-maximum) of a three-headed SPET camera. The reproducibility was 0.7% and the uniformity was 1.2%. Each rCBF sheet, containing between 8.3 and 80 MBq of 99mTcO4- depending on size, was first imaged on the collimator and then stacked into a 3D structure with constant 12 mm air spacing between the slices. SPET was performed with the sheets perpendicular to the central axis of the camera. The total weight of the stacked rCBF phantom in air was 63 g, giving a scatter contribution comparable to that of a point source in air. The overall attenuation losses were <20%. A second SPET study was performed with 12-mm polystyrene plates in between the radioactive sheets. With polystyrene plates, the total phantom weight was 2300 g, giving a scatter and attenuation magnitude similar to that of a patient study. With the proposed technique, it is possible to obtain "ideal" experimental images (essentially built up by primary photons) for comparison with "real

  7. [TUBERCULOUS CONSTRICTIVE PERICARDITIS DETECTED ON POSITRON EMISSION TOMOGRAPHY].

    PubMed

    Takakura, Hiroki; Sunada, Kouichi; Shimizu, Kunihiko

    2016-02-01

    A 72-year-old man presented with fever, dyspnea, and weight loss. He was referred to our hospital for further examination of the cause of the pleural effusions. Chest computed tomography showed pleural effusions, a pericardial effusion, and enlarged lymph nodes in the carina tracheae. We administered treatment for heart failure and conducted analyses for a malignant tumor. The pericardial effusion improved, but the pericardium was thickened. Positron emission tomography-computed tomography (PET-CT) showed fluorine-18 deoxyglucose accumulation at the superior fovea of the right clavicle, carina tracheae, superior mediastinum lymph nodes, and a thickened pericardium. Because these findings did not suggest malignancy, we assumed this was a tuberculous lesion. Echocardiography confirmed this finding as constrictive pericarditis; therefore, pericardiolysis was performed. Pathological examination showed features of caseous necrosis and granulomatous changes. Hence, the patient was diagnosed with tuberculous constrictive pericarditis. PET-CT serves as a useful tool for the diagnosis of tuberculous pericarditis. PMID:27263228

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

    PubMed Central

    Mattsson, Niklas

    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 during preclinical stages of Alzheimer’s disease. We included 437 non-demented subjects from the prospective, longitudinal Alzheimer’s Disease Neuroimaging Initiative (ADNI) study. All underwent 18F-florbetapir positron emission tomography and cerebrospinal fluid amyloid-β42 analysis at baseline and at least one additional positron emission tomography after a mean follow-up of 2.1 years (range 1.1–4.4 years). Group classifications were based on normal and abnormal cerebrospinal fluid and positron emission tomography results at baseline. We found that cases with isolated abnormal cerebrospinal fluid amyloid-β and normal positron emission tomography at baseline accumulated amyloid with a mean rate of 1.2%/year, which was similar to the rate in cases with both abnormal cerebrospinal fluid and positron emission tomography (1.2%/year, P = 0.86). The mean accumulation rate of those with isolated abnormal cerebrospinal fluid was more than three times that of those with both normal cerebrospinal fluid and positron emission tomography (0.35%/year, P = 0.018). The group differences were similar when analysing yearly change in standardized uptake value ratio of florbetapir instead of percentage change. Those with both abnormal cerebrospinal fluid and positron emission tomography deteriorated more in memory and hippocampal volume compared with the other groups (P < 0.001), indicating that they were closer to Alzheimer’s disease dementia. The results were replicated after

  9. Motion management in positron emission tomography/computed tomography for radiation treatment planning.

    PubMed

    Bettinardi, Valentino; Picchio, Maria; Di Muzio, Nadia; Gilardi, Maria Carla

    2012-09-01

    Hybrid positron emission tomography (PET)/computed tomography (CT) scanners combine, in a unique gantry, 2 of the most important diagnostic imaging systems, a CT and a PET tomograph, enabling anatomical (CT) and functional (PET) studies to be performed in a single study session. Furthermore, as the 2 scanners use the same spatial coordinate system, the reconstructed CT and PET images are spatially co-registered, allowing an accurate localization of the functional signal over the corresponding anatomical structure. This peculiarity of the hybrid PET/CT system results in improved tumor characterization for oncological applications, and more recently, it was found to be also useful for target volume definition (TVD) and treatment planning in radiotherapy (RT) applications. In fact, the use of combined PET/CT information has been shown to improve the RT treatment plan when compared with that obtained by a CT alone. A limiting factor to the accuracy of TVD by PET/CT is organ and tumor motion, which is mainly due to patient respiration. In fact, respiratory motion has a degrading effect on PET/CT image quality, and this is also critical for TVD, as it can lead to possible tumor missing or undertreatment. Thus, the management of respiratory motion is becoming an increasingly essential component in RT treatment planning; indeed, it has been recognized that the use of personalized motion information can improve TVD and, consequently, permit increased tumor dosage while sparing surrounding healthy tissues and organs at risk. This review describes the methods used for motion management in PET/CT for radiation treatment planning. The article covers the following: (1) problems caused by organ and lesion motion owing to respiration, and the artifacts generated on CT, PET, and PET/CT images; (2) data acquisition and processing techniques used to manage respiratory motion in PET/CT studies; and (3) the use of personalized motion information for TVD and radiation treatment planning.

  10. Positron Emission Tomography: Principles, Technology, and Recent Developments

    NASA Astrophysics Data System (ADS)

    Ziegler, Sibylle I.

    2005-04-01

    Positron emission tomography (PET) is a nuclear medical imaging technique for quantitative measurement of physiologic parameters in vivo (an overview of principles and applications can be found in [P.E. Valk, et al., eds. Positron Emission Tomography. Basic Science and Clinical Practice. 2003, Springer: Heidelberg]), based on the detection of small amounts of posi-tron-emitter-labelled biologic molecules. Various radiotracers are available for neuro-logical, cardiological, and oncological applications in the clinic and in research proto-cols. This overview describes the basic principles, technology, and recent develop-ments in PET, followed by a section on the development of a tomograph with ava-lanche photodiodes dedicated for small animal imaging as an example of efforts in the domain of high resolution tomographs.

  11. Studies on regional cerebral pH in patients with cerebral tumors using continuous inhalation of /sup 11/CO/sub 2/ and positron emission tomography

    SciTech Connect

    Brooks, D.J.; Beaney, R.P.; Thomas, D.G.; Marshall, J.; Jones, T.

    1986-10-01

    Regional cerebral pH (rpH) was measured in 12 patients with cerebral tumours and in 5 normal subjects using continuous inhalation of /sup 11/CO/sub 2/ and positron emission tomography (PET). Cerebral tumours with a disrupted blood-brain barrier (BBB) on computed tomography scanning had a similar rpH to that of equivalent regions of contralateral brain tissue (mean tumour rpH, 6.98; mean contralateral brain pH, 6.99). Cerebral tumours with an intact BBB were consistently found to be more alkaline than contralateral brain tissue (mean tumour rpH, 7.09). There was no significant difference between the mean rpH values obtained for peripheral cortical gray and central white matter in normal subjects (7.02 and 6.98, respectively). It is concluded that in spite of reports of raised levels of aerobic glycolysis in neoplastic tissue, there is no evidence that cerebral tumour rpH values are depressed.

  12. Enhancement of positron emission tomography-computed tomography image quality using the principle of stochastic resonance

    PubMed Central

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Sharma, Punit; Singh, Harmandeep; Patel, Chetan; Sarkar, Kaushik; Kumar, Rakesh; Bal, Chandra Sekhar

    2014-01-01

    Purpose: Acquisition of higher counts improves visual perception of positron emission tomography-computed tomography (PET-CT) image. Larger radiopharmaceutical doses (implies more radiation dose) are administered to acquire this count in a short time period. However, diagnostic information does not increase after a certain threshold of counts. This study was conducted to develop a post processing method based on principle of “stochastic resonance” to improve visual perception of the PET-CT image having a required threshold counts. Materials and Methods: PET-CT images (JPEG file format) with low, medium, and high counts in the image were included in this study. The image was corrupted with the addition of Poisson noise. The amplitude of the Poisson noise was adjusted by dividing each pixel by a constant 1, 2, 4, 8, 16, and 32. The best amplitude of the noise that gave best images quality was selected based on high value of entropy of the output image, high value of structural similarity index and feature similarity index. Visual perception of the image was evaluated by two nuclear medicine physicians. Results: The variation in structural and feature similarity of the image was not appreciable visually, but statistically images deteriorated as the noise amplitude increases although maintaining structural (above 70%) and feature (above 80%) similarity of input images in all cases. We obtained the best image quality at noise amplitude “4” in which 88% structural and 95% feature similarity of the input images was retained. Conclusion: This method of stochastic resonance can be used to improve the visual perception of the PET-CT image. This can indirectly lead to reduction of radiation dose. PMID:25400362

  13. Interest of the ordered subsets expectation maximization (OS-EM) algorithm in pinhole single-photon emission tomography reconstruction: a phantom study.

    PubMed

    Vanhove, C; Defrise, M; Franken, P R; Everaert, H; Deconinck, F; Bossuyt, A

    2000-02-01

    Pinhole single-photon emission tomography (SPET) has been proposed to improve the trade-off between sensitivity and resolution for small organs located in close proximity to the pinhole aperture. This technique is hampered by artefacts in the non-central slices. These artefacts are caused by truncation and by the fact that the pinhole SPET data collected in a circular orbit do not contain sufficient information for exact reconstruction. The ordered subsets expectation maximization (OS-EM) algorithm is a potential solution to these problems. In this study a three-dimensional OS-EM algorithm was implemented for data acquired on a single-head gamma camera equipped with a pinhole collimator (PH OS-EM). The aim of this study was to compare the PH OS-EM algorithm with the filtered back-projection algorithm of Feldkamp, Davis and Kress (FDK) and with the conventional parallel-hole geometry as a whole, using a line source phantom, Picker's thyroid phantom and a phantom mimicking the human cervical column. Correction for the angular dependency of the sensitivity in the pinhole geometry was based on a uniform flood acquisition. The projection data were shifted according to the measured centre of rotation. No correction was made for attenuation, scatter or distance-dependent camera resolution. The resolution measured with the line source phantom showed a significant improvement with PH OS-EM as compared with FDK, especially in the axial direction. Using Picker's thyroid phantom, one iteration with eight subsets was sufficient to obtain images with similar noise levels in uniform regions of interest to those obtained with the FDK algorithm. With these parameters the reconstruction time was 2.5 times longer than for the FDK method. Furthermore, there was a reduction in the artefacts caused by the circular orbit SPET acquisition. The images obtained from the phantom mimicking the human cervical column indicated that the improvement in image quality with PH OS-EM is relevant for

  14. Extra-nigral pathological conditions are common in Parkinson's disease with freezing of gait: an in vivo positron emission tomography study.

    PubMed

    Bohnen, Nicolaas I; Frey, Kirk A; Studenski, Stephanie; Kotagal, Vikas; Koeppe, Robert A; Constantine, Gregory M; Scott, Peter J H; Albin, Roger L; Müller, Martijn L T M

    2014-08-01

    Cholinergic denervation has been associated with falls and slower gait speed and β-amyloid deposition with greater severity of axial motor impairments in Parkinson disease (PD). However, little is known about the association between the presence of extra-nigral pathological conditions and freezing of gait (FoG). Patients with PD (n = 143; age, 65.5 ± 7.4 years, Hoehn and Yahr stage, 2.4 ± 0.6; Montreal Cognitive Assessment score, 25.9 ± 2.6) underwent [(11) C]methyl-4-piperidinyl propionate acetylcholinesterase and [(11) C]dihydrotetrabenazine dopaminergic PET imaging, and clinical, including FoG, assessment in the dopaminergic "off" state. A subset of subjects (n = 61) underwent [(11) C]Pittsburgh compound-B β-amyloid positron emission tomography (PET) imaging. Normative data were used to dichotomize abnormal β-amyloid uptake or cholinergic deficits. Freezing of gait was present in 20 patients (14.0%). Freezers had longer duration of disease (P = 0.009), more severe motor disease (P < 0.0001), and lower striatal dopaminergic activity (P = 0.013) compared with non-freezers. Freezing of gait was more common in patients with diminished neocortical cholinergic innervation (23.9%, χ(2)  = 5.56, P = 0.018), but not in the thalamic cholinergic denervation group (17.4%, χ(2)  = 0.26, P = 0.61). Subgroup analysis showed higher frequency of FoG with increased neocortical β-amyloid deposition (30.4%, Fisher Exact test: P = 0.032). Frequency of FoG was lowest with absence of both pathological conditions (4.8%), intermediate in subjects with single extra-nigral pathological condition (14.3%), and highest with combined neocortical cholinopathy and amyloidopathy (41.7%; Cochran-Armitage trend test, Z = 2.63, P = 0.015). Within the group of freezers, 90% had at least one of the two extra-nigral pathological conditions studied. Extra-nigral pathological conditions, in particular the combined presence of cortical

  15. Performance of principal component analysis and independent component analysis with respect to signal extraction from noisy positron emission tomography data - a study on computer simulated images.

    PubMed

    Razifar, Pasha; Muhammed, Hamid Hamed; Engbrant, Fredrik; Svensson, Per-Edvin; Olsson, Johan; Bengtsson, Ewert; Långström, Bengt; Bergström, Mats

    2009-01-01

    Multivariate image analysis tools are used for analyzing dynamic or multidimensional Positron Emission Tomography, PET data with the aim of noise reduction, dimension reduction and signal separation. Principal Component Analysis is one of the most commonly used multivariate image analysis tools, applied on dynamic PET data. Independent Component Analysis is another multivariate image analysis tool used to extract and separate signals. Because of the presence of high and variable noise levels and correlation in the different PET images which may confound the multivariate analysis, it is essential to explore and investigate different types of pre-normalization (transformation) methods that need to be applied, prior to application of these tools. In this study, we explored the performance of Principal Component Analysis (PCA) and Independent Component Analysis (ICA) to extract signals and reduce noise, thereby increasing the Signal to Noise Ratio (SNR) in a dynamic sequence of PET images, where the features of the noise are different compared with some other medical imaging techniques. Applications on computer simulated PET images were explored and compared. Application of PCA generated relatively similar results, with some minor differences, on the images with different noise characteristics. However, clear differences were seen with respect to the type of pre-normalization. ICA on images normalized using two types of normalization methods also seemed to perform relatively well but did not reach the improvement in SNR as PCA. Furthermore ICA seems to have a tendency under some conditions to shift over information from IC1 to other independent components and to be more sensitive to the level of noise. PCA is a more stable technique than ICA and creates better results both qualitatively and quantitatively in the simulated PET images. PCA can extract the signals from the noise rather well and is not sensitive to type of noise, magnitude and correlation, when the input

  16. Brain tumor imaging with synthesized /sup 18/F-fluorophenylalanine and positron emission tomography

    SciTech Connect

    Mineura, K.; Kowada, M.; Shishido, F.

    1989-06-01

    Two patients with cerebral gliomas were studied with 18F-fluorophenylalanine, newly synthesized by the electrophilic substitution reaction, using positron emission tomography. The tracer accumulated markedly in the tumor lesion and delineated the extent of the lesion. This new tracer will be promising in the diagnosis of gliomas.

  17. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast

    PubMed Central

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-01-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). PMID:27650938

  18. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast

    PubMed Central

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-01-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05).

  19. Relationship of computed tomography perfusion and positron emission tomography to tumour progression in malignant glioma

    SciTech Connect

    Yeung, Timothy P C; Yartsev, Slav; Lee, Ting-Yim; Wong, Eugene; He, Wenqing; Fisher, Barbara; VanderSpek, Lauren L; Macdonald, David; Bauman, Glenn

    2014-02-15

    Introduction: This study aimed to explore the potential for computed tomography (CT) perfusion and 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting sites of future progressive tumour on a voxel-by-voxel basis after radiotherapy and chemotherapy. Methods: Ten patients underwent pre-radiotherapy magnetic resonance (MR), FDG-PET and CT perfusion near the end of radiotherapy and repeated post-radiotherapy follow-up MR scans. The relationships between these images and tumour progression were assessed using logistic regression. Cross-validation with receiver operating characteristic (ROC) analysis was used to assess the value of these images in predicting sites of tumour progression. Results: Pre-radiotherapy MR-defined gross tumour; near-end-of-radiotherapy CT-defined enhancing lesion; CT perfusion blood flow (BF), blood volume (BV) and permeability-surface area (PS) product; FDG-PET standard uptake value (SUV); and SUV:BF showed significant associations with tumour progression on follow-up MR imaging (P < 0.0001). The mean sensitivity (±standard deviation), specificity and area under the ROC curve (AUC) of PS were 0.64 ± 0.15, 0.74 ± 0.07 and 0.72 ± 0.12 respectively. This mean AUC was higher than that of the pre-radiotherapy MR-defined gross tumour and near-end-of-radiotherapy CT-defined enhancing lesion (both AUCs = 0.6 ± 0.1, P ≤ 0.03). The multivariate model using BF, BV, PS and SUV had a mean AUC of 0.8 ± 0.1, but this was not significantly higher than the PS only model. Conclusion: PS is the single best predictor of tumour progression when compared to other parameters, but voxel-based prediction based on logistic regression had modest sensitivity and specificity.

  20. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast.

    PubMed

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-09-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). PMID:27650938

  1. Silicon as an unconventional detector in positron emission tomography

    NASA Astrophysics Data System (ADS)

    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.

  2. Brain single photon emission computed tomography in neonates

    SciTech Connect

    Denays, R.; Van Pachterbeke, T.; Tondeur, M.; Spehl, M.; Toppet, V.; Ham, H.; Piepsz, A.; Rubinstein, M.; Nol, P.H.; Haumont, D. )

    1989-08-01

    This study was designed to rate the clinical value of ({sup 123}I)iodoamphetamine (IMP) or ({sup 99m}Tc) hexamethyl propylene amine oxyme (HM-PAO) brain single photon emission computed tomography (SPECT) in neonates, especially in those likely to develop cerebral palsy. The results showed that SPECT abnormalities were congruent in most cases with structural lesions demonstrated by ultrasonography. However, mild bilateral ventricular dilatation and bilateral subependymal porencephalic cysts diagnosed by ultrasound were not associated with an abnormal SPECT finding. In contrast, some cortical periventricular and sylvian lesions and all the parasagittal lesions well visualized in SPECT studies were not diagnosed by ultrasound scans. In neonates with subependymal and/or intraventricular hemorrhage the existence of a parenchymal abnormality was only diagnosed by SPECT. These results indicate that ({sup 123}I)IMP or ({sup 99m}Tc)HM-PAO brain SPECT shows a potential clinical value as the neurodevelopmental outcome is clearly related to the site, the extent, and the number of cerebral lesions. Long-term clinical follow-up is, however, mandatory in order to define which SPECT abnormality is associated with neurologic deficit.

  3. Simultaneous iterative reconstruction of emission and attenuation images in positron emission tomography from emission data only.

    PubMed

    Landmann, M; Reske, S N; Glatting, G

    2002-09-01

    For quantitative image reconstruction in positron emission tomography attenuation correction is mandatory. In case that no data are available for the calculation of the attenuation correction factors one can try to determine them from the emission data alone. However, it is not clear if the information content is sufficient to yield an adequate attenuation correction together with a satisfactory activity distribution. Therefore, we determined the log likelihood distribution for a thorax phantom depending on the choice of attenuation and activity pixel values to measure the crosstalk between both. In addition an iterative image reconstruction (one-dimensional Newton-type algorithm with a maximum likelihood estimator), which simultaneously reconstructs the images of the activity distribution and the attenuation coefficients is used to demonstrate the problems and possibilities of such a reconstruction. As result we show that for a change of the log likelihood in the range of statistical noise, the associated change in the activity value of a structure is between 6% and 263%. In addition, we show that it is not possible to choose the best maximum on the basis of the log likelihood when a regularization is used, because the coupling between different structures mediated by the (smoothing) regularization prevents an adequate solution due to crosstalk. We conclude that taking into account the attenuation information in the emission data improves the performance of image reconstruction with respect to the bias of the activities, however, the reconstruction still is not quantitative.

  4. Positron Emission Tomography Detector Development for Plant Biology

    SciTech Connect

    Weisenberger, A G; McKisson, J; Stolin, A; Zorn, C; Howell, C R; Crowell, A S; Reid, C D; Majewski, S; Smith, M F

    2010-01-01

    There are opportunities for the development of new tools to advance plant biology research through the use of radionuclides. Thomas Jefferson National Accelerator Facility, Duke University, West Virginia University and the University of Maryland are collaborating on the development of radionuclide imaging technologies to facilitate plant biology research. Biological research into optimizing plant productivity under various environmental constraints, biofuel and carbon sequestration research are areas that could potentially benefit from new imaging technologies. Using 11CO2 tracers, the investigators at Triangle University Nuclear Laboratory / Duke University Phytotron are currently researching the dynamical responses of plants to environmental changes forecasted from increasing greenhouse trace gases involved in global change. The biological research primary focus is to investigate the impact of elevated atmospheric CO2 and nutrients limitation on carbon and nitrogen dynamics in plants. We report here on preliminary results of 11CO2 plant imaging experiments involving barley plants using Jefferson Lab dual planar positron emission tomography detectors to image 11CO2 in live barley plants. New detector designs will be developed based on the preliminary studies reported here and further planned.

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

    SciTech Connect

    Geltman, E.M.; Biello, D.; Welch, M.J.; Ter-Pogossian, M.M.; Roberts, R.; Sobel, B.E.

    1982-04-01

    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.

  6. Occipital lobe infarction and positron emission tomography.

    PubMed

    Tagawa, K; Nagata, K; Shishido, F

    1990-08-01

    Even though the PET study revealed a total infarct in the territory of the left PCA in our 3 cases of pure alexia, it is still obscure which part of the left occipital lobe is most closely associated with the occurrence of the pure alexia. In order to elucidate the intralobar localization of the pure alexia, it is needed to have an ideal case who shows an pure alexia due to the localized lesion within the left occipital lobe. Furthermore, high-resolution PET scanner will circumvent the problem in detecting the metabolism and blood flow in the corpus callosum which plays an important role in the pathogenesis. We have shown that the occlusion of the right PCA also produced a left unilateral agnosia which is one of the common neurological signs in the right MCA infarction. To tell whether the responsible lesion for the unilateral spatial agnosia differs between the PCA occlusion and the MCA occlusion, the correlation study should be carried out in a greater number of the subjects. Two distinctive neuropsychological manifestations, cerebral color blindness and prosopagnosia, have been considered to be produced by the bilateral occipital lesion. The PET studies disclosed reduction of blood flow and oxygen metabolism in both occipital lobes in our particular patient who exhibited cerebral color blindness and prosopagnosia.

  7. Positron emission tomography provides molecular imaging of biological processes

    PubMed Central

    Phelps, Michael E.

    2000-01-01

    Diseases are biological processes, and molecular imaging with positron emission tomography (PET) is sensitive to and informative of these processes. This is illustrated by detection of biological abnormalities in neurological disorders with no computed tomography or MRI anatomic changes, as well as even before symptoms are expressed. PET whole body imaging in cancer provides the means to (i) identify early disease, (ii) differentiate benign from malignant lesions, (iii) examine all organs for metastases, and (iv) determine therapeutic effectiveness. Diagnostic accuracy of PET is 8–43% higher than conventional procedures and changes treatment in 20–40% of the patients, depending on the clinical question, in lung and colorectal cancers, melanoma, and lymphoma, with similar findings in breast, ovarian, head and neck, and renal cancers. A microPET scanner for mice, in concert with human PET systems, provides a novel technology for molecular imaging assays of metabolism and signal transduction to gene expression, from mice to patients: e.g., PET reporter gene assays are used to trace the location and temporal level of expression of therapeutic and endogenous genes. PET probes and drugs are being developed together—in low mass amounts, as molecular imaging probes to image the function of targets without disturbing them, and in mass amounts to modify the target's function as a drug. Molecular imaging by PET, optical technologies, magnetic resonance imaging, single photon emission tomography, and other technologies are assisting in moving research findings from in vitro biology to in vivo integrative mammalian biology of disease. PMID:10922074

  8. Positron Emission Tomography in Breast Cancer

    PubMed Central

    Vercher-Conejero, Jose Luis; Pelegrí-Martinez, Laura; Lopez-Aznar, Diego; Cózar-Santiago, María del Puig

    2015-01-01

    Gradually, FDG-PET/CT has been strengthening within the diagnostic algorithms of oncological diseases. In many of these, PET/CT has shown to be useful at different stages of the disease: diagnosis, staging or re-staging, treatment response assessment, and recurrence. Some of the advantages of this imaging modality versus CT, MRI, bone scan, mammography, or ultrasound, are based on its great diagnostic capacity since, according to the radiopharmaceutical used, it reflects metabolic changes that often occur before morphological changes and therefore allows us to stage at diagnosis. Moreover, another advantage of this technique is that it allows us to evaluate the whole body so it can be very useful for the detection of distant disease. With regard to breast cancer, FDG-PET/CT has proven to be important when recurrence is suspected or in the evaluation of treatment response. The technological advancement of PET equipment through the development of new detectors and equipment designed specifically for breast imaging, and the development of more specific radiopharmaceuticals for the study of the different biological processes of breast cancer, will allow progress not only in making the diagnosis of the disease at an early stage but also in enabling personalized therapy for patients with breast cancer. PMID:26854143

  9. Newer positron emission tomography radiopharmaceuticals for radiotherapy planning: an overview

    PubMed Central

    Mukherjee, Anirban

    2016-01-01

    Positron emission tomography-computed tomography (PET-CT) has changed cancer imaging in the last decade, for better. It can be employed for radiation treatment planning of different cancers with improved accuracy and outcomes as compared to conventional imaging methods. 18F-fluorodeoxyglucose remains the most widely used though relatively non-specific cancer imaging PET tracer. A wide array of newer PET radiopharmaceuticals has been developed for targeted imaging of different cancers. PET-CT with such new PET radiopharmaceuticals has also been used for radiotherapy planning with encouraging results. In the present review we have briefly outlined the role of PET-CT with newer radiopharmaceuticals for radiotherapy planning and briefly reviewed the available literature in this regard. PMID:26904575

  10. Are we ready for positron emission tomography/computed tomography-based target volume definition in lymphoma radiation therapy?

    PubMed

    Yeoh, Kheng-Wei; Mikhaeel, N George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  11. Are We Ready for Positron Emission Tomography/Computed Tomography-based Target Volume Definition in Lymphoma Radiation Therapy?

    SciTech Connect

    Yeoh, Kheng-Wei; Mikhaeel, N. George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  12. Clinical experience with the first combined positron emission tomography/computed tomography scanner in Australia.

    PubMed

    Lau, W F Eddie; Binns, David S; Ware, Robert E; Ramdave, Shakher; Cachin, Florent; Pitman, Alexander G; Hicks, Rodney J

    2005-02-21

    Metabolic imaging with fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is increasing rapidly worldwide because of superior accuracy compared with conventional non-invasive techniques used for evaluating cancer. Limited anatomical information from FDG-PET images alone dictates that complementary use with structural imaging is required to optimise benefit. Recently, combined positron emission tomography/computed tomography (PET/CT) scanners have overtaken standalone PET scanners as the most commonly purchased PET devices. We describe our experience of over 5500 scans performed since the first PET/CT scanner in Australia was commissioned at the Peter MacCallum Cancer Centre (PMCC), Melbourne, in January 2002. Clinical indications for PET/CT scans performed at PMCC largely reflect current Medicare reimbursement policy. Advantages of PET/CT include greater patient comfort and higher throughput, greater diagnostic certainty and accuracy, improved biopsy methods, and better treatment planning. We believe PET/CT will underpin more effective and efficient imaging paradigms for many common tumours, and lead to a decrease in imaging costs. PMID:15720173

  13. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results. PMID:27625897

  14. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

    PubMed

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results. PMID:27625897

  15. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results.

  16. Concurrent Ultrasonic Tomography and Acoustic Emission in Solid Materials

    NASA Astrophysics Data System (ADS)

    Chow, Thomas M.

    A series of experiments were performed to detect stress induced changes in the elastic properties of various solid materials. A technique was developed where these changes were monitored concurrently by two methods, ultrasonic tomography and acoustic emission monitoring. This thesis discusses some experiments in which acoustic emission (AE) and ultrasonic tomography were performed on various samples of solid materials including rocks, concrete, metals, and fibre reinforced composites. Three separate techniques were used to induce stress in these samples. Disk shaped samples were subject to stress via diametral loading using an indirect tensile test geometry. Cylindrical samples of rocks and concrete were subject to hydraulic fracture tests, and rectangular samples of fibre reinforced composite were subject to direct tensile loading. The majority of the samples were elastically anisotropic. Full waveform acoustic emission and tomographic data were collected while these samples were under load to give information concerning changes in the structure of the material as it was undergoing stress change and/or failure. Analysis of this data indicates that AE and tomographic techniques mutually compliment each other to give a view of the stress induced elastic changes in the tested samples.

  17. Extramedullary Plasmacytoma of the Gallbladder Detected on Fluorine 18-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Fakhri, Asif Ali; Rodrigue, Paul David; Fakhri, Amena Fatima

    2016-01-01

    Extramedullary plasmacytoma is rare in patients with diagnosed multiple myeloma. Soft tissue plasmacytoma of the gallbladder is particularly uncommon and has been described in only a handful of cases. Diagnosis of gallbladder plasmacytoma with fluorine 18-fluorodeoxyglucose (F18-FDG) positron emission tomography/computed tomography (PET/CT) has not previously been reported. We present a 65-year-old female with a history of multiple myeloma who underwent a restaging F18-FDG-PET/CT which showed a focal area of hypermetabolic activity, corresponding to a nodular lesion within the posterior gallbladder wall. The patient underwent successful cholecystectomy, with surgical pathology revealing gallbladder plasmacytoma. A follow-up scan was negative for active malignancy. This is a novel case of gallbladder plasmacytoma diagnosed on whole-body F18-FDG PET/CT – thus demonstrating the clinical value of this imaging modality in staging, restaging, and surveillance for patients with multiple myeloma. PMID:27761300

  18. Unusual case of infantile fibrosarcoma evaluated on F-18 fluorodeoxyglucose positron emission tomography-computed tomography

    PubMed Central

    Bedmutha, Akshay; Singh, Natasha; Shivdasani, Divya; Gupta, Nitin

    2016-01-01

    Infantile fibrosarcoma (IFS) is a rare soft-tissue sarcoma originating from extremities and occasionally from axial soft tissue. The prognosis is good with favorable long-term survival. It is rarely metastasizing tumor, the chances being lesser with IFS originating from extremities. Use of neoadjuvant chemotherapy (NACT) as a treatment regime further reduces the chances of local relapse and distant metastasis. The organs commonly affected in metastatic IFS are lungs and lymph nodes. We report an unusual case of an IFS originating from extremity, which received NACT, yet presented with an early metastatic disease involving soft tissues and sparing lungs and lymph nodes, as demonstrated on fluorodeoxyglucose positron emission tomography-computed tomography. PMID:27385891

  19. A case of sarcoidosis diagnosed by positron emission tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yilmaz; Özdemir, Elif; Sentürk, Aysegül; Türkölmez, Seyda

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis. PMID:27385890

  20. A case of sarcoidosis diagnosed by positron emission tomography/computed tomography.

    PubMed

    Aksoy, Sabire Yilmaz; Özdemir, Elif; Sentürk, Aysegül; Türkölmez, Seyda

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis. PMID:27385890

  1. RPC: from High Energy Physics to Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Belli, G.; DeVecchi, C.; Giroletti, E.; Musitelli, G.; Nardò, R.; Necchi, M. M.; Pagano, D.; Ratti, S. P.; Riccardi, C.; Sani, G.; Torre, P.; Vitulo, P.; Viviani, C.

    2006-05-01

    A low cost gas-based charged particle detector, the Resistive Plate Counter (RPC) intensively used in fixed target and collider high energy experiments, is proposed as basic detector for Positron Emission Tomography. The performance of RPCs in terms of intrinsic space and time resolution and electronic pulse height response, makes it possible to transform standard RPCs into photon detectors and therefore to compensate for the photon sensitivity of scintillating crystals, when the efficiency of the complex crystal + photomultiplier is turned into standard quantum efficiency (q.e). Prototype multigap glass RPCs were developed which optimize γ detection efficiency and thus might substitute the traditional scintillators setups.

  2. Spatial emission tomography reconstruction using Pitman-Yor process

    SciTech Connect

    Fall, Mame Diarra; Mohammad-Djafari, Ali; Barat, Eric; Comtat, Claude

    2009-12-08

    In this paper, we address the problem of emission tomography spatial reconstruction in three dimensions following a Bayesian nonparametric approach. Our model makes use of a generalization of the Dirichlet process called Pitman-Yor process. The problem in this approach is to deal with the infinite representation of the distribution in the inference. So we propose an efficient Markov Chain Monte-Carlo sampling scheme which is able to generate samples from the posterior distribution of the activity distribution. An application to 3D-PET reconstruction is presented.

  3. [Positron emission tomography: a new modality in Brazilian nuclear medicine].

    PubMed

    Robilotta, Cecil Chow

    2006-01-01

    In nuclear medicine, radioactive substances are used to diagnose and treat disease. This medical specialty, that can provide information about the human body's physiologic and metabolic processes, has become a key diagnostic tool for the early detection of many different disorders, including various types of cancer. The present article describes the historical milestones in nuclear medicine; the basic physical principles underlying positron emission tomography (PET), which is an imaging method used to map the distribution of radiopharmaceuticals in the body for diagnostic and therapeutic purposes, and the current status of this modality in Brazil.

  4. The statistical efficiency of filtered backprojection in emission tomography

    SciTech Connect

    Kuruc, A.

    1995-09-25

    While there has been much interest in developing tomographic reconstruction algorithms that are more statistically efficient than filtered backprojection (FB), the degree of improvement possible has not been well understood. We present an algorithm-independent theory of statistical accuracy attainable in emission tomography that provides a geometrical interpretation of the statistical efficiency of FB. Our analysis shows that, in general, one can build unbiased estimators with smaller variance than FB. The improvement in performance is obtained by exploiting the range properties of the Radon transform.

  5. A Semiconductor-Based Positron Emission Tomography System

    NASA Astrophysics Data System (ADS)

    Oxley, D. C.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Grint, A. N.; Harkness, L. J.; Jones, M.; Judson, D. S.; Nolan, P. J.; Slee, M.; Unsworth, C.; Lazarus, I. H.

    2009-12-01

    This paper shall summarize the research conducted employing the high-purity germanium based small animal imaging system, SmartPET (SMall Animal Reconstructive Tomograph for Positron Emission Tomography). Geant4 simulations of the experimental setup were carried out in order to derive novel analysis procedures and quantify the system limitations. In this paper, we will focus on a gamma ray tracking approach devised to overcome germanium's high Compton scattering cross-section and on imaging challenging and complex phantom geometries. The potential of the developed tools and of the system itself will be discussed.

  6. Direct conversion semiconductor detectors in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Cates, Joshua W.; Gu, Yi; Levin, Craig S.

    2015-05-01

    Semiconductor detectors are playing an increasing role in ongoing research to improve image resolution, contrast, and quantitative accuracy in preclinical applications of positron emission tomography (PET). These detectors serve as a medium for direct detection of annihilation photons. Early clinical translation of this technology has shown improvements in image quality and tumor delineation for head and neck cancers, relative to conventional scintillator-based systems. After a brief outline of the basics of PET imaging and the physical detection mechanisms for semiconductor detectors, an overview of ongoing detector development work is presented. The capabilities of semiconductor-based PET systems and the current state of these devices are discussed.

  7. Detection of lung cancer in patients with pneumoconiosis by fluorodeoxyglucose-positron emission tomography/computed tomography: four cases.

    PubMed

    Yu, Hua; Zhang, Hua; Wang, Yanli; Cui, Xinjian; Han, Jiankui

    2013-01-01

    We report 4 cases of lung cancer in patients with pneumoconiosis detected by F18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), which could differentiate lung cancer and pneumoconiosis. FDG-PET/CT may be useful in cancer screening for patients with pneumoconiosis.

  8. Utility of 18F-choline photon emission tomography/computed tomography in the diagnosis of parathyroid adenoma

    PubMed Central

    Damle, Nishikant Avinash; Tripathi, Madhavi; Behera, Abhishek; Aggarwal, Sameer; Bal, Chandrasekhar; Aggarwal, Shipra; Aggarwal, Vivek; Kandasamy, Devasenathipathi; Taywade, Sameer

    2016-01-01

    Recently, the role of 18F-choline in the detection of parathyroid adenomas has been reported. At our institution, we are currently studying the role of this tracer in comparison to the standard methoxy-isobutyl-isonitrile.(MIBI) scan with single photon emission tomography/computed tomography. Our initial results show that 18F-choline is at least as good as 99mTc-MIBI scan. We present here a representative case of a 45-year-old woman with multiple skeletal lytic lesions and a high parathyroid hormone.(PTH) who underwent both these imaging techniques with concordant results, further confirmed by histopathology and postoperative fall in serum PTH levels. PMID:27385893

  9. Dizocilpine and reduced body temperature do not prevent methamphetamine-induced neurotoxicity in the vervet monkey: [11C]WIN 35,428 - positron emission tomography studies.

    PubMed

    Melega, W P; Lacan, G; Harvey, D C; Huang, S C; Phelps, M E

    1998-12-11

    [11C]WIN 35,428 (WIN), a cocaine analog that binds to the dopamine transporter (DAT), and positron emission tomography (PET) were used to evaluate the potential neuroprotective effects of dizocilpine (MK-801) on methamphetamine (MeAmp) induced neurotoxicity in the striatal dopamine system of the vervet monkey. MK-801 (1 mg/kg, i.m.) was administered 30 min prior to a neurotoxic MeAmp dosage for this species (2 x 2 mg/kg, 4 h apart); control subjects received MeAmp. MK-801 treated subjects were anesthetized by the drug for 6-8 h; throughout that period, a 2-3 degrees C decrease in body temperature was measured. At 1-2 weeks post-MeAmp, decreases of approximately 75% in striatal WIN binding were observed for both MK-801/MeAmp and MeAmp subjects. Thus, in this non-human primate species, the combination of MK-801 pretreatment and reduced body temperature did not provide protection from the MeAmp-induced loss of DAT. Further, the absence of an elevated body temperature during the acute MeAmp exposure period indicated that hyperthermia, per se, was not a necessary concomitant of the MeAmp neurotoxicity profile as has been previously demonstrated in rodents. These results provide evidence that different regulatory factors maintain the integrity of the rodent and primate striatal dopamine systems.

  10. Comparative study of thallium-201 single-photon emission computed tomography and electrocardiography in Duchenne and other types of muscular dystrophy

    SciTech Connect

    Yamamoto, S.; Matsushima, H.; Suzuki, A.; Sotobata, I.; Indo, T.; Matsuoka, Y.

    1988-04-01

    Single-photon emission computed tomography (SPECT) using thallium-201 was compared with 12-lead electrocardiography (ECG) in patients with Duchenne (29), facioscapulohumeral (7), limb-girdle (6) and myotonic (5) dystrophies, by dividing the left ventricular (LV) wall into 5 segments. SPECT showed thallium defects (37 patients, mostly in the posteroapical wall), malrotation (23), apical aneurysm (5) and dilatation (7). ECG showed abnormal QRS (36 patients), particularly as a posterolateral pattern (13). Both methods of assessment were normal in only 7 patients. The Duchenne type frequently showed both a thallium defect (particularly in the posteroapical wall) and an abnormal QRS (predominantly in the posterolateral wall); the 3 other types showed abnormalities over the 5 LV wall segments in both tests. The percent of agreement between the 2 tests was 64, 66, 70, 72 and 72 for the lateral, apical, anteroseptal, posterior and inferior walls, respectively. The 2 tests were discordant in 31% of the LV wall, with SPECT (+) but ECG (-) in 21% (mostly in the apicoinferior wall) and SPECT (-) but ECG (+) in 10% (mostly in the lateral wall). Some patients showed large SPECT hypoperfusion despite minimal electrocardiographic changes. ECG thus appeared to underestimate LV fibrosis and to reflect posteroapical rather than posterolateral dystrophy in its posterolateral QRS pattern. In this disease, extensive SPECT hypoperfusion was also shown, irrespective of clinical subtype and skeletal involvement.

  11. Clinical significance of reverse redistribution on technetium-99m tetrofosmin single-photon emission computed tomography: an 18-month follow-up study

    PubMed Central

    Swinkels, B.M.; Hooghoudt, T.E.H.; Schoenmakers, E.A.J.M.; Zinder, C.G.; de Boo, T.M.; Verheugt, F.W.A.

    2003-01-01

    Background The clinical and prognostic significance of reverse redistribution on technetium-99m (99mTc) single-photon emission computed tomography (SPECT) is unclear. Objectives To determine outcomes of chest pain patients showing reverse redistribution after 99mTc tetrofosmin SPECT versus SPECT showing no reverse redistribution. Methods Patient outcomes (death, nonfatal myocardial infarction, coronary artery bypass grafting and percutaneous transluminal coronary angioplasty) within 18 months after 99mTc tetrofosmin SPECT were determined in two populations of ambulatory patients, most of whom had been evaluated because of chest pain: a population of 57 patients whose SPECT images showed reverse redistribution without reversible or fixed defects, versus a control population of 98 patients whose SPECT images were normal (no reverse redistribution, no reversible defects, no fixed defects). Results Stepwise logistic regression analysis showed that the population of patients with reverse redistribution did not have a worse 18-month outcome in comparison with the control population of patients without reverse redistribution (3.5% versus 9.2%, respectively; p=0.15 corrected for age and gender). Conclusion Reverse redistribution on 99mTc tetrofosmin SPECT does not appear to be an unfavourable prognostic factor in ambulatory chest pain patients. PMID:25696192

  12. Correlation between decreased motor activity and dopaminergic degeneration in the ventrolateral putamen in monkeys receiving repeated MPTP administrations: a positron emission tomography study.

    PubMed

    Nagai, Yuji; Minamimoto, Takafumi; Ando, Kiyoshi; Obayashi, Shigeru; Ito, Hiroshi; Ito, Nobuhiko; Suhara, Tetsuya

    2012-05-01

    Parkinson's disease (PD) patients have remarkably reduced levels of dopaminergic biomarkers in the caudal putamen. However, the relationship between motor impairments and the localization of intrastriatal dopaminergic degeneration in monkey PD models remains unclear. To identify the striatal areas with dopaminergic dysfunction responsible for motor impairments, we measured changes in both general motor activity and in vivo dopaminergic biomarkers in three cynomolgus monkeys that repeatedly received 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), starting in the normal state and continuing until after tremor appearance. Binding of dopamine transporters (DAT) and D(2) receptors were measured by positron emission tomography (PET) using [(11)C]PE2I and [(11)C]raclopride, respectively. Region-of-interest-based regression analysis demonstrated the degree of general motor activity reduction to be explained by striatal DAT binding but not by D(2) receptor binding. Furthermore, voxel-based analysis revealed a significant correlation between reduced general motor activity and decreased DAT binding, specifically in the ventrolateral putamen, which corresponds to the area receiving upper body motor inputs from the primary motor cortex. These results suggest that specific functional deficits in PD models are closely related to the degeneration of dopaminergic terminals in the striatal subregion responsible for these functions and that the level of deficit is dependent on the degree of degeneration.

  13. Positron Emission Tomography: Current Challenges and Opportunities for Technological Advances in Clinical and Preclinical Imaging Systems.

    PubMed

    Vaquero, Juan José; Kinahan, Paul

    2015-01-01

    Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The physics of the emission, and the detection of the coincident photons, give PET imaging unique capabilities for both very high sensitivity and accurate estimation of the in vivo concentration of the radiotracer. PET imaging has been widely adopted as an important clinical modality for oncological, cardiovascular, and neurological applications. PET imaging has also become an important tool in preclinical studies, particularly for investigating murine models of disease and other small-animal models. However, there are several challenges to using PET imaging systems. These include the fundamental trade-offs between resolution and noise, the quantitative accuracy of the measurements, and integration with X-ray computed tomography and magnetic resonance imaging. In this article, we review how researchers and industry are addressing these challenges.

  14. Positron Emission Tomography: Current Challenges and Opportunities for Technological Advances in Clinical and Preclinical Imaging Systems.

    PubMed

    Vaquero, Juan José; Kinahan, Paul

    2015-01-01

    Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The physics of the emission, and the detection of the coincident photons, give PET imaging unique capabilities for both very high sensitivity and accurate estimation of the in vivo concentration of the radiotracer. PET imaging has been widely adopted as an important clinical modality for oncological, cardiovascular, and neurological applications. PET imaging has also become an important tool in preclinical studies, particularly for investigating murine models of disease and other small-animal models. However, there are several challenges to using PET imaging systems. These include the fundamental trade-offs between resolution and noise, the quantitative accuracy of the measurements, and integration with X-ray computed tomography and magnetic resonance imaging. In this article, we review how researchers and industry are addressing these challenges. PMID:26643024

  15. Noninvasive imaging of islet grafts using positron-emission tomography

    NASA Astrophysics Data System (ADS)

    Lu, Yuxin; Dang, Hoa; Middleton, Blake; Zhang, Zesong; Washburn, Lorraine; Stout, David B.; Campbell-Thompson, Martha; Atkinson, Mark A.; Phelps, Michael; Gambhir, Sanjiv Sam; Tian, Jide; Kaufman, Daniel L.

    2006-07-01

    Islet transplantation offers a potential therapy to restore glucose homeostasis in type 1 diabetes patients. However, islet transplantation is not routinely successful because most islet recipients gradually lose graft function. Furthermore, serological markers of islet function are insensitive to islet loss until the latter stages of islet graft rejection. A noninvasive method of monitoring islet grafts would aid in the assessment of islet graft survival and the evaluation of interventions designed to prolong graft survival. Here, we show that recombinant adenovirus can engineer isolated islets to express a positron-emission tomography (PET) reporter gene and that these islets can be repeatedly imaged by using microPET after transplantation into mice. The magnitude of signal from engineered islets implanted into the axillary cavity was directly related to the implanted islet mass. PET signals attenuated over the following weeks because of the transient nature of adenovirus-mediated gene expression. Because the liver is the preferred site for islet implantation in humans, we also tested whether islets could be imaged after transfusion into the mouse liver. Control studies revealed that both intrahepatic islet transplantation and hyperglycemia altered the biodistribution kinetics of the PET probe systemically. Although transplanted islets were dispersed throughout the liver, clear signals from the liver region of mice receiving PET reporter-expressing islets were detectable for several weeks. Viral transduction, PET reporter expression, and repeated microPET imaging had no apparent deleterious effects on islet function after implantation. These studies lay a foundation for noninvasive quantitative assessments of islet graft survival using PET. diabetes | transplantation

  16. PDE regularization for Bayesian reconstruction of emission tomography

    NASA Astrophysics Data System (ADS)

    Wang, Zhentian; Zhang, Li; Xing, Yuxiang; Zhao, Ziran

    2008-03-01

    The aim of the present study is to investigate a type of Bayesian reconstruction which utilizes partial differential equations (PDE) image models as regularization. PDE image models are widely used in image restoration and segmentation. In a PDE model, the image can be viewed as the solution of an evolutionary differential equation. The variation of the image can be regard as a descent of an energy function, which entitles us to use PDE models in Bayesian reconstruction. In this paper, two PDE models called anisotropic diffusion are studied. Both of them have the characteristics of edge-preserving and denoising like the popular median root prior (MRP). We use PDE regularization with an Ordered Subsets accelerated Bayesian one step late (OSL) reconstruction algorithm for emission tomography. The OS accelerated OSL algorithm is more practical than a non-accelerated one. The proposed algorithm is called OSEM-PDE. We validated the OSEM-PDE using a Zubal phantom in numerical experiments with attenuation correction and quantum noise considered, and the results are compared with OSEM and an OS version of MRP (OSEM-MRP) reconstruction. OSEM-PDE shows better results both in bias and variance. The reconstruction images are smoother and have sharper edges, thus are more applicable for post processing such as segmentation. We validate this using a k-means segmentation algorithm. The classic OSEM is not convergent especially in noisy condition. However, in our experiment, OSEM-PDE can benefit from OS acceleration and keep stable and convergent while OSEM-MRP failed to converge.

  17. Muscle use during double poling evaluated by positron emission tomography.

    PubMed

    Bojsen-Møller, Jens; Losnegard, Thomas; Kemppainen, Jukka; Viljanen, Tapio; Kalliokoski, Kari K; Hallén, Jostein

    2010-12-01

    Due to the complexity of movement in cross-country skiing (XCS), the muscle activation patterns are not well elucidated. Previous studies have applied surface electromyography (SEMG); however, recent gains in three-dimensional (3D) imaging techniques such as positron emission tomography (PET) have rendered an alternative approach to investigate muscle activation. The purpose of the present study was to examine muscle use during double poling (DP) at two work intensities by use of PET. Eight male subjects performed two 20-min DP bouts on separate days. Work intensity was ∼ 53 and 74% of peak oxygen uptake (Vo(2peak)), respectively. During exercise 188 ± 8 MBq of [(18)F]fluorodeoxyglucose ([(18)F]FDG) was injected, and subsequent to exercise a full-body PET scan was conducted. Regions of interest (ROI) were defined within 15 relevant muscles, and a glucose uptake index (GUI) was determined for all ROIs. The muscles that span the shoulder and elbow joints, the abdominal muscles, and hip flexors displayed the greatest GUI during DP. Glucose uptake did not increase significantly from low to high intensity in most upper body muscles; however, an increased GUI (P < 0.05) was seen for the knee flexor (27%) and extensor muscles (16%), and for abdominal muscles (21%). The present data confirm previous findings that muscles of the upper limb are the primary working muscles in DP. The present data further suggest that when exercise intensity increases, the muscles that span the lumbar spine, hip, and knee joints contribute increasingly. Finally, PET provides a promising alternative or supplement to existing methods to assess muscle activation in complex human movements.

  18. Exploring spatial overlap of high-uptake regions derived from dual tracer positron emission tomography-computer tomography imaging using 18F-fluorodeoxyglucose and 18F-fluorodeoxythymidine in nonsmall cell lung cancer patients: a prospective pilot study.

    PubMed

    Liu, Jing; Li, Chengqiang; Hu, Man; Lu, Jie; Shi, Xiaorong; Xing, Ligang; Sun, Xindong; Fu, Zheng; Yu, Jinming; Meng, Xue

    2015-05-01

    Interest is growing in radiotherapy to nonuniformly boost radioresistant regions within nonsmall cell lung cancer (NSCLC) using molecular imaging techniques. The complexity of tumor behavior is beyond the ability of any single radiotracer to reveal. We hold dual tracer positron emission tomography-computer tomography (PET/CT) imaging with fluorodeoxyglucose (FDG) and fluorodeoxythymidine (FLT) for NSCLC patients to offer an integrated overlook of tumor biological behaviors quantitatively and localizationally, which may help biological target volume delineation and subvolume boost.Pathological confirmed that NSCLC patients were eligible. FDG and FLT PET/CT were performed for each patient before anticancer treatment and coregistrated for analysis. Maximum and mean standardized uptake values (SUVmax and SUVmean) were calculated automatically. Metabolic volumes (MVs) were delineated by a fixed 50% of SUVmax in FDG PET/CT and proliferative volumes (PVs) were delineated by 50% to 90% of SUVmax with 10% interval in FLT PET/CT. Overlap ratio (OR) were determined as overlapped volume between MV and PV divided PV. Conventional contrast-enhanced CT-based intensity-modulated radiotherapy (IMRT) plans with and without additional PET/CT-guided subtarget boost were made for each of the 5 typical NSCLC patients. Dosimetric parameters derived from dose-volume histogram, tumor control probability (TCP), and normal tissue complication probability (NTCP) of lung, esophagus, heart, and spinal cord were calculated and compared.Thirty-one patients were prospectively included and 23 were selected for analysis. Totally, 23 primary diseases, 41 metastatic lymph nodes, and 15 metastatic lesions were positive in dual PET/CTs and included for analysis. Median ORs increased from 58.61% to 93.12% under thresholds of 50% of SUVmax in FDG PET/CT and increased thresholds from 50% to 90% of SUVmax in FLT PET/CT. Based on conventional IMRT, additional boost to union of high FDG (determined by 50

  19. Budget impact from the incorporation of positron emission tomography – computed tomography for staging lung cancers

    PubMed Central

    Biz, Aline Navega; Caetano, Rosângela

    2015-01-01

    OBJECTIVE To estimate the budget impact from the incorporation of positron emission tomography (PET) in mediastinal and distant staging of non-small cell lung cancer. METHODS The estimates were calculated by the epidemiological method for years 2014 to 2018. Nation-wide data were used about the incidence; data on distribution of the disease´s prevalence and on the technologies’ accuracy were from the literature; data regarding involved costs were taken from a micro-costing study and from Brazilian Unified Health System (SUS) database. Two strategies for using PET were analyzed: the offer to all newly-diagnosed patients, and the restricted offer to the ones who had negative results in previous computed tomography (CT) exams. Univariate and extreme scenarios sensitivity analyses were conducted to evaluate the influence from sources of uncertainties in the parameters used. RESULTS The incorporation of PET-CT in SUS would imply the need for additional resources of 158.1 BRL (98.2 USD) million for the restricted offer and 202.7 BRL (125.9 USD) million for the inclusive offer in five years, with a difference of 44.6 BRL (27.7 USD) million between the two offer strategies within that period. In absolute terms, the total budget impact from its incorporation in SUS, in five years, would be 555 BRL (345 USD) and 600 BRL (372.8 USD) million, respectively. The costs from the PET-CT procedure were the most influential parameter in the results. In the most optimistic scenario, the additional budget impact would be reduced to 86.9 BRL (54 USD) and 103.8 BRL (64.5 USD) million, considering PET-CT for negative CT and PET-CT for all, respectively. CONCLUSIONS The incorporation of PET in the clinical staging of non-small cell lung cancer seems to be financially feasible considering the high budget of the Brazilian Ministry of Health. The potential reduction in the number of unnecessary surgeries may cause the available resources to be more efficiently allocated. PMID:26274871

  20. Role of Positron Emission Tomography-Computed Tomography in the Management of Anal Cancer

    SciTech Connect

    Mistrangelo, Massimiliano; Pelosi, Ettore; Bello, Marilena; Ricardi, Umberto; Milanesi, Enrica; Cassoni, Paola; Baccega, Massimo; Filippini, Claudia; Racca, Patrizia; Lesca, Adriana; Munoz, Fernando H.; Fora, Gianluca; Skanjeti, Andrea; Cravero, Francesca; Morino, Mario

    2012-09-01

    Purpose: Pre- and post-treatment staging of anal cancer are often inaccurate. The role of positron emission tomograpy-computed tomography (PET-CT) in anal cancer is yet to be defined. The aim of the study was to compare PET-CT with CT scan, sentinel node biopsy results of inguinal lymph nodes, and anal biopsy results in staging and in follow-up of anal cancer. Methods and Materials: Fifty-three consecutive patients diagnosed with anal cancer underwent PET-CT. Results were compared with computed tomography (CT), performed in 40 patients, and with sentinel node biopsy (SNB) (41 patients) at pretreatment workup. Early follow-up consisted of a digital rectal examination, an anoscopy, a PET-CT scan, and anal biopsies performed at 1 and 3 months after the end of treatment. Data sets were then compared. Results: At pretreatment assessment, anal cancer was identified by PET-CT in 47 patients (88.7%) and by CT in 30 patients (75%). The detection rates rose to 97.9% with PET-CT and to 82.9% with CT (P=.042) when the 5 patients who had undergone surgery prior to this assessment and whose margins were positive at histological examination were censored. Perirectal and/or pelvic nodes were considered metastatic by PET-CT in 14 of 53 patients (26.4%) and by CT in 7 of 40 patients (17.5%). SNB was superior to both PET-CT and CT in detecting inguinal lymph nodes. PET-CT upstaged 37.5% of patients and downstaged 25% of patients. Radiation fields were changed in 12.6% of patients. PET-CT at 3 months was more accurate than PET-CT at 1 month in evaluating outcomes after chemoradiation therapy treatment: sensitivity was 100% vs 66.6%, and specificity was 97.4% vs 92.5%, respectively. Median follow-up was 20.3 months. Conclusions: In this series, PET-CT detected the primary tumor more often than CT. Staging of perirectal/pelvic or inguinal lymph nodes was better with PET-CT. SNB was more accurate in staging inguinal lymph nodes.

  1. Positron emission tomography radiopharmaceuticals for imaging brain Beta-amyloid.

    PubMed

    Vallabhajosula, Shankar

    2011-07-01

    Alzheimer's disease (AD) is defined histologically by the presence of extracellular β-amyloid (Aβ) plaques and intraneuronal neurofibrillary tangles in the cerebral cortex. The diagnosis of dementia, along with the prediction of who will develop dementia, has been assisted by magnetic resonance imaging and positron emission tomography (PET) by using [(18)F]fluorodeoxyglucose (FDG). These techniques, however, are not specific for AD. Based on the chemistry of histologic staining dyes, several Aβ-specific positron-emitting radiotracers have been developed to image neuropathology of AD. Among these, [(11)C]PiB is the most studied Aβ-binding PET radiopharmaceutical in the world. The histologic and biochemical specificity of PiB binding across different regions of the AD brain was demonstrated by showing a direct correlation between Aβ-containing amyloid plaques and in vivo [(11)C]PiB retention measured by PET imaging. Because (11)C is not ideal for commercialization, several (18)F-labeled tracers have been developed. At this time, [(18)F]3'-F-PiB (Flutemetamol), (18)F-AV-45 (Florbetapir), and (18)F-AV-1 (Florbetaben) are undergoing extensive phase II and III clinical trials. This article provides a brief review of the amyloid biology and chemistry of Aβ-specific (11)C and (18)F-PET radiopharmaceuticals. Clinical trials have clearly documented that PET radiopharmaceuticals capable of assessing Aβ content in vivo in the brains of AD subjects and subjects with mild cognitive impairment will be important as diagnostic agents to detect in vivo amyloid brain pathology. In addition, PET amyloid imaging will also help test the amyloid cascade hypothesis of AD and as an aid to assess the efficacy of antiamyloid therapeutics currently under development in clinical trials.

  2. Multiple pulmonary sclerosing hemangiomas (pneumocytoma) mimicking lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Rajan, Firoz; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-01-01

    Pulmonary sclerosing hemangioma (PSH), or the alternative name of “sclerosing pneumocytoma,” is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary or multiple pulmonary nodules on radiologic imaging studies. Few articles have been reported to describe the fluorodeoxyglucose positron emission tomography (FDG PET) findings about PSH. The authors describe an interesting but uncommonly encountered cause of false positive FDG PET scan in the thorax in a 25-year-old woman, a known case of arteriovenous malformation of oral cavity who underwent embolization and presented with incidental detection of bilateral lung nodules. She is asymptomatic and is on follow-up. PMID:25210285

  3. Multiple pulmonary sclerosing hemangiomas (pneumocytoma) mimicking lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Rajan, Firoz; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-07-01

    Pulmonary sclerosing hemangioma (PSH), or the alternative name of "sclerosing pneumocytoma," is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary or multiple pulmonary nodules on radiologic imaging studies. Few articles have been reported to describe the fluorodeoxyglucose positron emission tomography (FDG PET) findings about PSH. The authors describe an interesting but uncommonly encountered cause of false positive FDG PET scan in the thorax in a 25-year-old woman, a known case of arteriovenous malformation of oral cavity who underwent embolization and presented with incidental detection of bilateral lung nodules. She is asymptomatic and is on follow-up.

  4. Positron Emission Tomography imaging with the SmartPET system

    NASA Astrophysics Data System (ADS)

    Cooper, R. J.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Grint, A. N.; Harkness, L. J.; Nolan, P. J.; Oxley, D. C.; Scraggs, D. P.; Mather, A. R.; Lazarus, I.; Simpson, J.

    2009-07-01

    The Small Animal Reconstruction Tomograph for Positron Emission Tomography (SmartPET) project is the development of a small animal Positron Emission Tomography (PET) demonstrator based on the use of High-Purity Germanium (HPGe) detectors and state of the art digital electronics. The experimental results presented demonstrate the current performance of this unique system. By performing high precision measurements of one of the SmartPET HPGe detectors with a range of finely collimated gamma-ray beams the response of the detector as a function of gamma-ray interaction position has been quantified, facilitating the development of parametric Pulse Shape Analysis (PSA) techniques and algorithms for the correction of imperfections in detector performance. These algorithms have then been applied to data from PET imaging measurements using two such detectors in conjunction with a specially designed rotating gantry. In this paper we show how the use of parametric PSA approaches allows over 60% of coincident events to be processed and how the nature and complexity of an event has direct implications for the quality of the resulting image.

  5. Tomography studies of volcanic complexes

    NASA Astrophysics Data System (ADS)

    Koulakov, I.; Gordeev, E. I.; West, M.; Yeguas, A. G.; Luehr, B.-G.; Jakovlev, A.

    2012-04-01

    We present an overview of recent results of seismic tomography studies of different volcanic complexes performed in collaboration with different research teams. In first three examples corresponding to Central Andes, areas around Merapi volcano and Toba caldera, the tomographic images down to 100-200 km depth reveal the paths of fluids and melts which escape from the subducting plate and feed the arc volcanoes. In all these areas, the shapes of the paths are different depending on particular features of the subduction regimes, such as type of the overriding plate, age of the slab, rate of the subduction etc. Next group of studies covers detailed tomographic studies of local structures beneath selected volcanoes. Beneath the Spurr Volcano (Alaska) we clearly observe a thin vertical channel with anomalously high Vp/Vs ratio beneath the main cone. Beneath the volcanoes of Kluchevskoy group (Kamchatka) seismic images reveal complex structure of channels and intermediate magma reservoirs. In the mantle we detect an anomaly with very high Vp/Vs ratio reaching 2.2, which looks as a top of the mantle channel feeding the volcanoes of the group. For this group we observed the time variations of seismic structure based on more than 10 years of continuous data. We detect considerable variations in Vp/Vs ratio in the crust related to large eruptions of Kluchevskoy and Bezymyanny volcanoes in 2005. The last example is another time-lapse tomography model obtained for the El Hierro volcano in Canaries based on earthquake swarm occurred from July to October 2011. During this period we observe regular deepening of a large body with high Vp/Vs ratio, which is interpreted as a magma reservoir, together with lowering of seismicity.

  6. Positron Emission Tomography for the Assessment of Myocardial Viability

    PubMed Central

    2010-01-01

    Executive Summary In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Assessment of Myocardial Viability, an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients undergoing viability assessment. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities. After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies that can be used for the assessment of myocardial viability: positron emission tomography, cardiac magnetic resonance imaging, dobutamine echocardiography, and dobutamine echocardiography with contrast, and single photon emission computed tomography. A 2005 review conducted by MAS determined that positron emission tomography was more sensitivity than dobutamine echocardiography and single photon emission tomography and dominated the other imaging modalities from a cost-effective standpoint. However, there was inadequate evidence to compare positron emission tomography and cardiac magnetic resonance imaging. Thus, this report focuses on this comparison only. For both technologies, an economic analysis was also completed. The Non-Invasive Cardiac Imaging Technologies for the Assessment of Myocardial Viability is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.html Positron Emission Tomography for the Assessment of Myocardial Viability: An Evidence-Based Analysis Magnetic Resonance Imaging for the Assessment of Myocardial Viability: An Evidence-Based Analysis Objective The objective of this analysis is to assess the

  7. Positron emission tomography detects tissue metabolic activity in myocardial segments with persistent thallium perfusion defects

    SciTech Connect

    Brunken, R.; Schwaiger, M.; Grover-McKay, M.; Phelps, M.E.; Tillisch, J.; Schelbert, H.R.

    1987-09-01

    Positron emission tomography with /sup 13/N-ammonia and /sup 18/F-2-deoxyglucose was used to assess myocardial perfusion and glucose utilization in 51 myocardial segments with a stress thallium defect in 12 patients. Myocardial infarction was defined by a concordant reduction in segmental perfusion and glucose utilization, and myocardial ischemia was identified by preservation of glucose utilization in segments with rest hypoperfusion. Of the 51 segments studied, 36 had a fixed thallium defect, 11 had a partially reversible defect and 4 had a completely reversible defect. Only 15 (42%) of the 36 segments with a fixed defect and 4 (36%) of the 11 segments with a partially reversible defect exhibited myocardial infarction on study with positron tomography. In contrast, residual myocardial glucose utilization was identified in the majority of segments with a fixed (58%) or a partially reversible (64%) thallium defect. All of the segments with a completely reversible defect appeared normal on positron tomography. Apparent improvement in the thallium defect on delayed images did not distinguish segments with ischemia from infarction. Thus, positron emission tomography reveals evidence of persistent tissue metabolism in the majority of segments with a fixed or partially resolving stress thallium defect, implying that markers of perfusion alone may underestimate the extent of viable tissue in hypoperfused myocardial segments.

  8. Simultaneous iterative reconstruction for emission and attenuation images in positron emission tomography.

    PubMed

    Glatting, G; Wuchenauer, M; Reske, S N

    2000-09-01

    The quality of the attenuation correction strongly influences the outcome of the reconstructed emission scan in positron emission tomography. Usually the attenuation correction factors are calculated from the transmission and blank scan and thereafter applied during the reconstruction on the emission data. However, this is not an optimal treatment of the available data, because the emission data themselves contain additional information about attenuation: The optimal treatment must use this information for the determination of the attenuation correction factors. Therefore, our purpose is to investigate a simultaneous emission and attenuation image reconstruction using a maximum likelihood estimator, which takes the attenuation information in the emission data into account. The total maximum likelihood function for emission and transmission is used to derive a one-dimensional Newton-like algorithm for the calculation of the emission and attenuation image. Log-likelihood convergence, mean differences, and the mean of squared differences for the emission image and the attenuation correction factors of a mathematical thorax phantom were determined and compared. As a result we obtain images improved with respect to log likelihood in all cases and with respect to our figures of merit in most cases. We conclude that the simultaneous reconstruction can improve the performance of image reconstruction.

  9. Plasma Emission Profile Recreation using Soft X-Ray Tomography

    NASA Astrophysics Data System (ADS)

    Page, J. W.; Mauel, M. E.; Levesque, J. P.

    2015-11-01

    With sufficient views from multiple diode arrays, soft X-ray tomography is an invaluable plasma diagnostic because it is a non-perturbing method to reconstruct the emission within the interior of the plasma. In preparation for the installation of new SXR arrays in HBT-EP, we compute high-resolution tomographic reconstructions of discharges having kink-like structures that rotate nearly rigidly. By assuming a uniform angular mapping from the kink mode rotation, Δϕ ~ ωΔ t, a temporal sequence from a single 16-diode fan array represents as many as 16 x 100 independent views. We follow the procedure described by Wang and Granetz and use Bessel basis functions to take the inverse Radon transform. This transform is fit to our data using a least-squares method to estimate the internal SXR emissivity as a sum of polar functions. By varying different parameters of the transformation, we optimize the quality of our recreation of the emission profile and quantify how the reconstruction changes with the azimuthal order of the transform. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  10. Cardiac emission tomography in patients using 201thallium. A new technique for perfusion scintigraphy.

    PubMed

    Dymond, D S; Stone, D L; Elliott, A T; Britton, K E; Spurrell, R A

    1979-06-01

    The distribution of 201thallium (Tl) in the myocardium has been studied by the new technique of emission tomography, and compared with standard gamma camera images in 5 patients. Tomographic imaging was carried out using a dual-detector scanner operated under the single-photon technique. Initial results have been promising, with visualisation of resting perfusion defects in patients with recent infarction and those with ventricular aneurysms. Emission tomography has also been performed at exercise, and has shown tracer deficits in the distribution of significant coronary stenoses. This new approach to myocardial perfusion scintigraphy may lead to improved sensitivity for detecting apical and inferior wall abnormalities by providing depth information not available from a conventional two-dimensional image. PMID:315854

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

    SciTech Connect

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-05-01

    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.

  12. SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY: COMPENSATION FOR CONSTANT ATTENUATION

    SciTech Connect

    Gullberg, Grant T.; Budinger, Thomas F.

    1980-06-01

    A back-projection of filtered projection (BKFIL) reconstruction algorithm is presented that is applicable to single-photon emission computed tomography (ECT) in the presence of a constant attenuating medium such as the brain. The filters used in transmission computed tomography (TCT) - comprised of a ramp multiplied by window functions - are modified so that the single-photon ECT filter is a function of the constant attenuation coefficient. The filters give good reconstruction results with sufficient angular and lateral sampling. With continuous samples the BKFIL algorithm has a point spread function that is the Hankel transform of the window function. The resolution and s tistical properties of the filters are demonstrated by various simulations. Statistical formulas for the reconstructed image show that the square of the percent-root-mean square uncertainty (%RMS) of the reconstruction is inversely proportional to the total measured counts. The results indicate that constant attenuation can be compensated for in single-photon ECT by using an attenuation-dependent filter that reconstructs the transverse section reliably. Computer time requirements are two times that of conventional TCT or positron ECT and there is no increase in memory requirements.

  13. Practical implementation of tetrahedral mesh reconstruction in emission tomography.

    PubMed

    Boutchko, R; Sitek, A; Gullberg, G T

    2013-05-01

    This paper presents a practical implementation of image reconstruction on tetrahedral meshes optimized for emission computed tomography with parallel beam geometry. Tetrahedral mesh built on a point cloud is a convenient image representation method, intrinsically three-dimensional and with a multi-level resolution property. Image intensities are defined at the mesh nodes and linearly interpolated inside each tetrahedron. For the given mesh geometry, the intensities can be computed directly from tomographic projections using iterative reconstruction algorithms with a system matrix calculated using an exact analytical formula. The mesh geometry is optimized for a specific patient using a two stage process. First, a noisy image is reconstructed on a finely-spaced uniform cloud. Then, the geometry of the representation is adaptively transformed through boundary-preserving node motion and elimination. Nodes are removed in constant intensity regions, merged along the boundaries, and moved in the direction of the mean local intensity gradient in order to provide higher node density in the boundary regions. Attenuation correction and detector geometric response are included in the system matrix. Once the mesh geometry is optimized, it is used to generate the final system matrix for ML-EM reconstruction of node intensities and for visualization of the reconstructed images. In dynamic PET or SPECT imaging, the system matrix generation procedure is performed using a quasi-static sinogram, generated by summing projection data from multiple time frames. This system matrix is then used to reconstruct the individual time frame projections. Performance of the new method is evaluated by reconstructing simulated projections of the NCAT phantom and the method is then applied to dynamic SPECT phantom and patient studies and to a dynamic microPET rat study. Tetrahedral mesh-based images are compared to the standard voxel-based reconstruction for both high and low signal-to-noise ratio

  14. Evaluating Positron Emission Tomography Use in Differentiated Thyroid Cancer

    PubMed Central

    Esfandiari, Nazanene H.; Papaleontiou, Maria; Worden, Francis P.; Haymart, Megan R.

    2015-01-01

    Background: Using the Surveillance, Epidemiology, and End Results—Medicare database, a substantial increase was found in the use of positron emission tomography (PET) scans after 2004 in differentiated thyroid cancer (DTC) patients. The reason for the increased utilization of the PET scan was not clear based on available the data. Therefore, the indications for and outcomes of PET scans performed at an academic institution were evaluated. Methods: A retrospective cohort study was performed of DTC patients who underwent surgery at the University of Michigan Health System from 2006 to 2011. After identifying patients who underwent a PET scan, indications, rate of positive PET scans, and impact on management were evaluated. For positive scans, the location of disease was characterized, and presence of disease on other imaging was determined. Results: Of the 585 patients in the cohort, 111 (19%) patients had 200 PET scans performed for evaluation of DTC. Indications for PET scan included: elevated thyroglobulin and negative radioiodine scan in 52 scans (26.0%), thyroglobulin antibodies in 13 scans (6.5%), rising thyroglobulin in 18 scans (9.0%), evaluation of abnormality on other imaging in 22 scans (11.0%), evaluation of extent of disease in 33 scans (16.5%), follow-up of previous scan in 57 scans (28.5%), other indications in two scans (1.0%), and unclear indications in three scans (1.5%). The PET scan was positive in 124 studies (62.0%); positivity was identified in the thyroid bed on 25 scans, cervical or mediastinal lymph nodes on 105 scans, lung on 28 scans, bone on four scans, and other areas on 14 scans. Therapy following PET scan was surgery in 66 cases (33.0%), chemotherapy or radiation in 23 cases (11.5%), observation in 110 cases (55.0%), and palliative care in one case (0.5%). Disease was identifiable on other imaging in 66% of cases. PET scan results changed management in 59 cases (29.5%). Conclusions: In this academic medical center, the PET scan was

  15. A Review on Segmentation of Positron Emission Tomography Images

    PubMed Central

    Foster, Brent; Bagci, Ulas; Mansoor, Awais; Xu, Ziyue; Mollura, Daniel J.

    2014-01-01

    Positron Emission Tomography (PET), a non-invasive functional imaging method at the molecular level, images the distribution of biologically targeted radiotracers with high sensitivity. PET imaging provides detailed quantitative information about many diseases and is often used to evaluate inflammation, infection, and cancer by detecting emitted photons from a radiotracer localized to abnormal cells. In order to differentiate abnormal tissue from surrounding areas in PET images, image segmentation methods play a vital role; therefore, accurate image segmentation is often necessary for proper disease detection, diagnosis, treatment planning, and follow-ups. In this review paper, we present state-of-the-art PET image segmentation methods, as well as the recent advances in image segmentation techniques. In order to make this manuscript self-contained, we also briefly explain the fundamentals of PET imaging, the challenges of diagnostic PET image analysis, and the effects of these challenges on the segmentation results. PMID:24845019

  16. Central Nervous System Drug Evaluation Using Positron Emission Tomography

    PubMed Central

    Maeda, Jun; Shimada, Hitoshi; Nogami, Tsuyoshi; Arakawa, Ryosuke; Takano, Harumasa; Higuchi, Makoto; Ito, Hiroshi; Okubo, Yoshiro; Suhara, Tetsuya

    2011-01-01

    In conventional pharmacological research in the field of mental disorders, pharmacological effect and dose have been estimated by ethological approach and in vitro data of affinity to the site of action. In addition, the frequency of administration has been estimated from drug kinetics in blood. However, there is a problem regarding an objective index of drug effects in the living body. Furthermore, the possibility that the concentration of drug in blood does not necessarily reflect the drug kinetics in target organs has been pointed out. Positron emission tomography (PET) techniques have made progress for more than 20 years, and made it possible to measure the distribution and kinetics of small molecule components in living brain. In this article, we focused on rational drug dosing using receptor occupancy and proof-of-concept of drugs in the drug development process using PET. PMID:23431048

  17. Simulation of Medical Imaging Systems: Emission and Transmission Tomography

    NASA Astrophysics Data System (ADS)

    Harrison, Robert L.

    Simulation is an important tool in medical imaging research. In patient scans the true underlying anatomy and physiology is unknown. We have no way of knowing in a given scan how various factors are confounding the data: statistical noise; biological variability; patient motion; scattered radiation, dead time, and other data contaminants. Simulation allows us to isolate a single factor of interest, for instance when researchers perform multiple simulations of the same imaging situation to determine the effect of statistical noise or biological variability. Simulations are also increasingly used as a design optimization tool for tomographic scanners. This article gives an overview of the mechanics of emission and transmission tomography simulation, reviews some of the publicly available simulation tools, and discusses trade-offs between the accuracy and efficiency of simulations.

  18. Positron emission tomography (PET) advances in neurological applications

    NASA Astrophysics Data System (ADS)

    Sossi, V.

    2003-09-01

    Positron Emission Tomography (PET) is a functional imaging modality used in brain research to map in vivo neurotransmitter and receptor activity and to investigate glucose utilization or blood flow patterns both in healthy and disease states. Such research is made possible by the wealth of radiotracers available for PET, by the fact that metabolic and kinetic parameters of particular processes can be extracted from PET data and by the continuous development of imaging techniques. In recent years great advancements have been made in the areas of PET instrumentation, data quantification and image reconstruction that allow for more detailed and accurate biological information to be extracted from PET data. It is now possible to quantitatively compare data obtained either with different tracers or with the same tracer under different scanning conditions. These sophisticated imaging approaches enable detailed investigation of disease mechanisms and system response to disease and/or therapy.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Resolution and Sensitivity in Positron Emission Tomography Imaging:. New Frontiers

    NASA Astrophysics Data System (ADS)

    Sossi, V.

    2004-07-01

    The combination of new detector technologies and rapidly increasing computing power is contributing to major developments in positron emission tomography (PET) imaging. The uniqueness of PET resides in its ability to detect very small concentrations of radioactively labeled tracers specifically designed to investigate selected biological functions. The desire to quantitatively observe increasingly complex biological processes together with the need of furthering research in small animal models of disease are pushing the limits of imaging spatial resolution and sensitivity. Resolution of approximately 10 mm3 is now achievable in human size brain scanners, while 1 mm3 can almost be reached in small animal imaging. Such ability will enable a more detailed exploration of healthy and disease function with the ultimate goal of imaging at a molecular level and of detecting pre-clinical disease induced changes.

  1. Fuzzy-rule-based image reconstruction for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Mondal, Partha P.; Rajan, K.

    2005-09-01

    Positron emission tomography (PET) and single-photon emission computed tomography have revolutionized the field of medicine and biology. Penalized iterative algorithms based on maximum a posteriori (MAP) estimation eliminate noisy artifacts by utilizing available prior information in the reconstruction process but often result in a blurring effect. MAP-based algorithms fail to determine the density class in the reconstructed image and hence penalize the pixels irrespective of the density class. Reconstruction with better edge information is often difficult because prior knowledge is not taken into account. The recently introduced median-root-prior (MRP)-based algorithm preserves the edges, but a steplike streaking effect is observed in the reconstructed image, which is undesirable. A fuzzy approach is proposed for modeling the nature of interpixel interaction in order to build an artifact-free edge-preserving reconstruction. The proposed algorithm consists of two elementary steps: (1) edge detection, in which fuzzy-rule-based derivatives are used for the detection of edges in the nearest neighborhood window (which is equivalent to recognizing nearby density classes), and (2) fuzzy smoothing, in which penalization is performed only for those pixels for which no edge is detected in the nearest neighborhood. Both of these operations are carried out iteratively until the image converges. Analysis shows that the proposed fuzzy-rule-based reconstruction algorithm is capable of producing qualitatively better reconstructed images than those reconstructed by MAP and MRP algorithms. The reconstructed images are sharper, with small features being better resolved owing to the nature of the fuzzy potential function.

  2. Pulmonary malignant melanoma with distant metastasis assessed by positron emission tomography-computed tomography.

    PubMed

    Kim, So Ri; Yoon, Ha-Yong; Jin, Gong Yong; Choe, Yeong Hun; Park, Seung Yong; Lee, Yong Chul

    2016-07-01

    Melanoma is a cutaneous malignant neoplasm of melanocytes. Primary malignant melanoma (MM) of the lung is very rare. Although previous reports have described the radiologic features of pulmonary MM, its rarity means that many factors are unknown. Thus, radiologic diagnosis is very difficult. Furthermore, there is little information regarding diagnostic application and/or the usefulness of [(18)F]-fluorine-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (FDG-PET-CT) for primary pulmonary MM. A 69-year-old patient with a productive cough lasting three weeks was admitted to our hospital. Chest CT showed a large single mass with a multi-lobulated margin and homogeneous enhancement in the right upper lobe, which was subsequently diagnosed as a primary pulmonary MM with multiple metastases. On PET-CT images, the pulmonary mass and multiple bone lesions showed very increased uptakes of FDG. Considering that pulmonary metastasis from a mucocutaneous melanoma is the main differential diagnosis of primary pulmonary MM, systemic assessment of the whole body is more important than for other types of lung malignancies. This report introduces PET-CT as a useful diagnostic modality for pulmonary MM, especially in cases of distant multiple metastases. PMID:27385996

  3. Positron emission tomography / computerized tomography evaluation of primary Hodgkin's disease of liver.

    PubMed

    Gota, V S; Purandare, N C; Gujral, S; Shah, S; Nair, R; Rangarajan, V

    2009-01-01

    Occurrence of primary Hodgkin's lymphoma (PHL) of the liver is extremely rare. We report on a case of a 60-year-old male who presented with liver mass and B-symptomatology. Hepatoma or hepatic metastasis from a gastrointestinal primary was initially suspected. Tumor markers like AFP, CEA, Total PSA, and CA-19.9 were within normal limits. Positron Emission Tomography / Computerized Tomography (PET/CT) revealed a large hepatic lesion and a nodal mass in the porta hepatis. A liver biopsy was consistent with Hodgkin's lymphoma. There was complete regression of the hepatic lesion and evidence of shrinkage of the nodal mass following four cycles of chemotherapy. 18F Fluro -de-oxy Glucose (FDG) PET / CT in this case helped in establishing a primary hepatic lymphoma by demonstrating the absence of pathologically hypermetabolic foci in any other nodes or organs. PET / CT scan is a useful adjunct to conventional imaging and histopathology, not only to establish the initial diagnosis, but also to monitor treatment response in PHL.

  4. Role of positron emission tomography-computed tomography in non-small cell lung cancer

    PubMed Central

    Garg, Pankaj Kumar; Singh, Saurabh Kumar; Prakash, Gaurav; Jakhetiya, Ashish; Pandey, Durgatosh

    2016-01-01

    Lung cancer is the leading cause of cancer-related mortality worldwide. Non-small cell carcinoma and small cell carcinoma are the main histological subtypes and constitutes around 85% and 15% of all lung cancer respectively. Multimodality treatment plays a key role in the successful management of lung cancer depending upon the histological subtype, stage of disease, and performance status. Imaging modalities play an important role in the diagnosis and accurate staging of the disease, in assessing the response to neoadjuvant therapy, and in the follow-up of the patients. Last decade has witnessed voluminous upsurge in the use of positron emission tomography-computed tomography (PET-CT); role of PET-CT has widened exponentially in the management of lung cancer. The present article reviews the role of 18-fluoro-deoxyglucose PET-CT in the management of non small cell lung cancer with emphasis on staging of the disease and the assessment of response to neoadjuvant therapy based on available literature. PMID:27018223

  5. EEG, transmission computed tomography, and positron emission tomography with fluorodeoxyglucose /sup 18/F. Their use in adults with gliomas

    SciTech Connect

    Newmark, M.E.; Theodore, W.H.; Sato, S.; De La Paz, R.; Patronas, N.; Brooks, R.; Jabbari, B.; Di Chiro, G.

    1983-10-01

    We evaluated the relationship between findings from EEG, transmission computed tomography (CT), and positron emission tomography in 23 adults with gliomas. The cortical metabolic rate was suppressed in patients with and without focal slowing. Focal delta activity was not related to involvement of gray or white matter. Rhythmic delta activity and focal attenuation of background amplitude on EEG, however, were correlated with involvement of the thalamus.

  6. Retroperitoneal Endometriosis: A Possible Cause of False Positive Finding at 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Maffione, Anna Margherita; Panzavolta, Riccardo; Lisato, Laura Camilla; Ballotta, Maria; D'Isanto, Mariangela Zanforlini; Rubello, Domenico

    2015-01-01

    Endometriosis is a frequent and clinically relevant problem in young women. Laparoscopy is still the gold standard for the diagnosis of endometriosis, but frequently both morphologic and functional imaging techniques are involved in the diagnostic course before achieving a conclusive diagnosis. We present a case of a patient affected by infiltrating retroperitoneal endometriosis falsely interpreted as a malignant mass by contrast-enhanced magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography/computed tomography. PMID:26097425

  7. Iofetamine I 123 single photon emission computed tomography is accurate in the diagnosis of Alzheimer's disease

    SciTech Connect

    Johnson, K.A.; Holman, B.L.; Rosen, T.J.; Nagel, J.S.; English, R.J.; Growdon, J.H. )

    1990-04-01

    To determine the diagnostic accuracy of iofetamine hydrochloride I 123 (IMP) with single photon emission computed tomography in Alzheimer's disease, we studied 58 patients with AD and 15 age-matched healthy control subjects. We used a qualitative method to assess regional IMP uptake in the entire brain and to rate image data sets as normal or abnormal without knowledge of subjects'clinical classification. The sensitivity and specificity of IMP with single photon emission computed tomography in AD were 88% and 87%, respectively. In 15 patients with mild cognitive deficits (Blessed Dementia Scale score, less than or equal to 10), sensitivity was 80%. With the use of a semiquantitative measure of regional cortical IMP uptake, the parietal lobes were the most functionally impaired in AD and the most strongly associated with the patients' Blessed Dementia Scale scores. These results indicated that IMP with single photon emission computed tomography may be a useful adjunct in the clinical diagnosis of AD in early, mild disease.

  8. Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

    PubMed Central

    Wong, Ka-Kit; Gandhi, Arpit; Viglianti, Benjamin L; Fig, Lorraine M; Rubello, Domenico; Gross, Milton D

    2016-01-01

    AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders. METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology. RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for 99mTc-sestamibi parathyroid scintigraphy and 99mTc-pertechnetate thyroid scintigraphy, 123I- or 131I-radioiodine for staging of differentiated thyroid carcinoma, 111In- and 99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, 131I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and 123I- or 131I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma. CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy

  9. Attenuation correction in emission tomography using the emission data—A review

    PubMed Central

    Li, Yusheng

    2016-01-01

    The problem of attenuation correction (AC) for quantitative positron emission tomography (PET) had been considered solved to a large extent after the commercial availability of devices combining PET with computed tomography (CT) in 2001; single photon emission computed tomography (SPECT) has seen a similar development. However, stimulated in particular by technical advances toward clinical systems combining PET and magnetic resonance imaging (MRI), research interest in alternative approaches for PET AC has grown substantially in the last years. In this comprehensive literature review, the authors first present theoretical results with relevance to simultaneous reconstruction of attenuation and activity. The authors then look back at the early history of this research area especially in PET; since this history is closely interwoven with that of similar approaches in SPECT, these will also be covered. We then review algorithmic advances in PET, including analytic and iterative algorithms. The analytic approaches are either based on the Helgason–Ludwig data consistency conditions of the Radon transform, or generalizations of John’s partial differential equation; with respect to iterative methods, we discuss maximum likelihood reconstruction of attenuation and activity (MLAA), the maximum likelihood attenuation correction factors (MLACF) algorithm, and their offspring. The description of methods is followed by a structured account of applications for simultaneous reconstruction techniques: this discussion covers organ-specific applications, applications specific to PET/MRI, applications using supplemental transmission information, and motion-aware applications. After briefly summarizing SPECT applications, we consider recent developments using emission data other than unscattered photons. In summary, developments using time-of-flight (TOF) PET emission data for AC have shown promising advances and open a wide range of applications. These techniques may both remedy

  10. Combined computed tomography and fluorodeoxyglucose positron emission tomography in the diagnosis of prosthetic valve endocarditis: a case series

    PubMed Central

    2014-01-01

    Background The diagnosis of prosthetic valve endocarditis is challenging. The gold standard for prosthetic valve endocarditis diagnosis is trans-esophageal echocardiography. However, trans-esophageal echocardiography may result in negative findings or yield images difficult to differentiate from thrombus in patients with prosthetic valve endocarditis. Combined computed tomography and fluorodeoxyglucose positron emission tomography is a potentially promising diagnostic tool for several infectious conditions and it has also been employed in patients with prosthetic valve endocarditis but data are still scant. Case presentations We reviewed the charts of 6 patients with prosthetic aortic valves evaluated for suspicion of prosthetic valve endocarditis, at two different hospital, over a 3-year period. We found 3 patients with early-onset PVE cases and blood cultures yielding Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus lugdunensis, respectively; and 3 late-onset cases in the remaining 3 patients with isolation in the blood of Streptococcus bovis, Candida albicans and P. aeruginosa, respectively. Initial trans-esophageal echocardiography was negative in all the patients, while fluorodeoxyglucose positron emission tomography showed images suspicious for prosthetic valve endocarditis. In 4 out of 6 patients valve replacement was done with histology confirming the prosthetic valve endocarditis diagnosis. After an adequate course of antibiotic therapy fluorodeoxyglucose positron emission tomography showed resolution of prosthetic valve endocarditis in all the patients. Conclusion Our experience confirms the potential role of fluoroseoxyglucose positron emission tomography in the diagnosis and follow-up of prosthetic valve endocarditis. PMID:24418206

  11. Molecular Imaging of Transporters with Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    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

  12. Decreased cerebral cortical serotonin transporter binding in ecstasy users: a positron emission tomography/[11C]DASB and structural brain imaging study

    PubMed Central

    Lerch, Jason; Furukawa, Yoshiaki; Tong, Junchao; McCluskey, Tina; Wilkins, Diana; Houle, Sylvain; Meyer, Jeffrey; Mundo, Emanuela; Wilson, Alan A.; Rusjan, Pablo M.; Saint-Cyr, Jean A.; Guttman, Mark; Collins, D. Louis; Shapiro, Colin; Warsh, Jerry J.; Boileau, Isabelle

    2010-01-01

    Animal data indicate that the recreational drug ecstasy (3,4-methylenedioxymethamphetamine) can damage brain serotonin neurons. However, human neuroimaging measurements of serotonin transporter binding, a serotonin neuron marker, remain contradictory, especially regarding brain areas affected; and the possibility that structural brain differences might account for serotonin transporter binding changes has not been explored. We measured brain serotonin transporter binding using [11C] N,N-dimethyl-2-(2-amino-4-cyanophenylthio) benzylamine in 50 control subjects and in 49 chronic (mean 4 years) ecstasy users (typically one to two tablets bi-monthly) withdrawn from the drug (mean 45 days). A magnetic resonance image for positron emission tomography image co-registration and structural analyses was acquired. Hair toxicology confirmed group allocation but also indicated use of other psychoactive drugs in most users. Serotonin transporter binding in ecstasy users was significantly decreased throughout all cerebral cortices (range –19 to –46%) and hippocampus (–21%) and related to the extent of drug use (years, maximum dose), but was normal in basal ganglia and midbrain. Substantial overlap was observed between control and user values except for insular cortex, in which 51% of ecstasy user values fell below the lower limit of the control range. Voxel-based analyses confirmed a caudorostral gradient of cortical serotonin transporter binding loss with occipital cortex most severely affected. Magnetic resonance image measurement revealed no overall regional volume differences between groups; however, a slight left-hemispheric biased cortical thinning was detected in methamphetamine-using ecstasy users. The serotonin transporter binding loss was not related to structural changes or partial volume effect, use of other stimulant drugs, blood testosterone or oestradiol levels, major serotonin transporter gene promoter polymorphisms, gender, psychiatric status, or self

  13. Positron Emission Tomography for the Assessment of Myocardial Viability

    PubMed Central

    2005-01-01

    ventricular (LV) viability is, therefore, critical in deciding whether a patient with coronary artery disease and severe LV dysfunction should undergo revascularization, receive a heart transplant, or remain on medical therapy. Assessment of Left Ventricular Viability Techniques for assessing myocardial viability depend on the measurement of a specific characteristic of viable myocytes such as cell membrane integrity, preserved metabolism, mitochondria integrity, and preserved contractile reserve. In Ontario, single photon emission computed tomography (SPECT) using radioactive 201thallium is the most commonly used technique followed by dobutamine echocardiography. Newer techniques include SPECT using technetium tracers, cardiac magnetic resonance imaging, and PET, the subject of this review. Positron Emission Tomography PET is a nuclear imaging technique based on the metabolism of radioactive analogs of normal substrates such as glucose and water. The radiopharmaceutical used most frequently in myocardial viability assessment is F18 fluorodeoxyglucose (FDG), a glucose analog. The procedure involves the intravenous administration of FDG under controlled glycemic conditions, and imaging with a PET scanner. The images are reconstructed using computer software and analyzed visually or semi-quantitatively, often in conjunction with perfusion images. Dysfunctional but stunned myocardium is characterized by normal perfusion and normal FDG uptake; hibernating myocardium exhibits reduced perfusion and normal/enhanced FDG uptake (perfusion/metabolism mismatch), whereas scar tissue is characterized by reduction in both perfusion and FDG uptake (perfusion/metabolism match). Review Strategy The Medical Advisory Secretariat used a search strategy similar to that used in the 2001 ICES review to identify English language reports of health technology assessments and primary studies in selected databases, published from January 1, 2001 to April 20, 2005. Patients of interest were those with

  14. [Inflammatory activity in Takayasu arteritis. Detection through positron emission tomography (PET)].

    PubMed

    Alexánderson, Erick; Soto, María Elena; Ricalde, Alejandro; Meave, Aloha; Reyes, Pedro

    2005-01-01

    Takayasu arteritis (TA) is a chronic disease that affects mainly the aorta. Its etiology is still unknown, nevertheless it predominates in women and initiates primarily in the youth. This disease seems to have two different stages, an early stage that is characterized by an inflammatory process and a later stage characterized by vascular occlusion. Unitl now, diagnosis and classification of TA are made clinically, based on ACR; criteria and imaging studies as computed tomography and aorta angiographies. Currently, new imaging, non invasive studies, such as magnetic resonance (MRI) and positron emission tomography (PET) are being used. PET technique could be helpful in the diagnosis and detection of inflammatory activity in patients with TA because of its capacity to detect increased metabolism. We present the case of a female patient with TA diagnosis, which demonstrated clinical inflammatory activity that was corroborated by laboratory studies, MRI and PET. PMID:15909745

  15. Positron emission tomography-computed tomography in the diagnostic evaluation of smoldering multiple myeloma: identification of patients needing therapy

    PubMed Central

    Siontis, B; Kumar, S; Dispenzieri, A; Drake, M T; Lacy, M Q; Buadi, F; Dingli, D; Kapoor, P; Gonsalves, W; Gertz, M A; Rajkumar, S V

    2015-01-01

    We studied 188 patients with a suspected smoldering multiple myeloma (MM) who had undergone a positron emission tomography-computed tomography (PET-CT) scan as part of their clinical evaluation. PET-CT was positive (clinical radiologist interpretation of increased bone uptake and/or evidence of lytic bone destruction) in 74 patients and negative in 114 patients. Of these, 25 patients with a positive PET-CT and 97 patients with a negative PET-CT were observed without therapy and formed the study cohort (n=122). The probability of progression to MM within 2 years was 75% in patients with a positive PET-CT observed without therapy compared with 30% in patients with a negative PET-CT; median time to progression was 21 months versus 60 months, respectively, P=0.0008. Of 25 patients with a positive PET-CT, the probability of progression was 87% at 2 years in those with evidence of underlying osteolysis (n=16) and 61% in patients with abnormal PET-CT uptake but no evidence of osteolysis (n=9). Patients with positive PET-CT and evidence of underlying osteolysis have a high risk of progression to MM within 2 years when observed without therapy. These observations support recent changes to imaging requirements in the International Myeloma Working Group updated diagnostic criteria for MM. PMID:26495861

  16. Multidimensional characterization of an entangled photon-pair source via stimulated emission tomography.

    PubMed

    Fang, B; Liscidini, M; Sipe, J E; Lorenz, V O

    2016-05-01

    Using stimulated emission tomography, we characterize an entangled photon-pair source in the energy and polarization degrees of freedom, with a precision far exceeding what could be obtained by quantum state tomography. Through this multidimensional tomography we find that energy-polarization correlations are a cause of polarization-entanglement degradation, demonstrating that this technique provides useful information for source engineering and can accelerate the development of quantum information processing systems dependent on many degrees of freedom. PMID:27137611

  17. Regulation of the compounding of positron emission tomography drugs.

    PubMed

    Hung, J C

    2001-01-15

    Controversial aspects of the regulatory framework for compounding drug products used in positron emission tomography (PET) are discussed. The Food and Drug Administration Modernization Act of 1997 (FDAMA), which amends the Federal Food, Drug, and Cosmetic Act (FFDCA), required that FDA establish approval (new drug application [NDA] and abbreviated new drug application [ANDA]) procedures and current good manufacturing practice (CGMP) requirements for PET drugs; this seems to conflict with differentiation between manufacturing and compounding in FFDCA. Compounding by pharmacists is implied in the FDAMA section on PET, but specific mention of "pharmacist" needs to be included. Congress apparently did not intend for compounded PET drugs to be regulated differently from other drugs. Although FDA has waived NDA and ANDA fees for three PET radiopharmaceuticals, revision of FDAMA to exempt PET drug products from regulations placed on manufacturing is needed. Without relief from the current regulations, many academic PET centers are likely to close; this would violate FDAMA's stated intent of making PET available to patients at reasonable cost. Also problematic is FDAMA's prohibition of compounding "regularly or in inordinate amounts" a product that is commercially available; the common PET radiopharmaceutical fludeoxyglucose F 18 injection, for example, is commercially available. A sensible alternative to NDA or ANDA and CGMP requirements would be the enforcement of USP standards for PET drugs by state boards of pharmacy.

  18. Mathematical model of single-photon emission computed tomography

    SciTech Connect

    Clough, A.V.

    1986-01-01

    Single-photon emission computed tomography (SPECT) is a nuclear-medicine imaging technique that has been shown to provide clinically useful images of radionuclide distributions within the body. The problem of quantitative determination of tomographic activity images from a projection data set leads to a mathematical inverse problem which is formulated as an integral equation. The solution of this problem then depends on an accurate mathematical model as well as a reliable and efficient inversion algorithm. The effects of attenuation and Compton scatter within the body have been incorporated into the model in the hopes of providing a more physically realistic mathematical model. The attenuated Radon transform is the mathematical basis of SPECT. In this work, the case of constant attenuation is reviewed and a new proof of the Tretiak-Metz algorithm is presented. A space-domain version of the inverse attenuated Radon transform is derived. A special case of this transform that is applicable when the object is rotationally symmetric, and attenuated Abel transform is derived, and its inverse is found. A numerical algorithm for the implementation of the inverse attenuated Radon transform with constant attenuation is described and computer simulations are performed to demonstrate the results of the inversion procedure. With the use of the single-scatter approximation and an energy-windowed detector, the effects of Compton scatter are incorporated into the model. The data are then taken to be the sum of primary photons and single-scattered photons.

  19. European health telematics networks for positron emission tomography

    NASA Astrophysics Data System (ADS)

    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.

  20. Geoscientific process monitoring with positron emission tomography (GeoPET)

    NASA Astrophysics Data System (ADS)

    Kulenkampff, Johannes; Gründig, Marion; Zakhnini, Abdelhamid; Lippmann-Pipke, Johanna

    2016-08-01

    Transport processes in geomaterials can be observed with input-output experiments, which yield no direct information on the impact of heterogeneities, or they can be assessed by model simulations based on structural imaging using µ-CT. Positron emission tomography (PET) provides an alternative experimental observation method which directly and quantitatively yields the spatio-temporal distribution of tracer concentration. Process observation with PET benefits from its extremely high sensitivity together with a resolution that is acceptable in relation to standard drill core sizes. We strongly recommend applying high-resolution PET scanners in order to achieve a resolution on the order of 1 mm. We discuss the particularities of PET applications in geoscientific experiments (GeoPET), which essentially are due to high material density. Although PET is rather insensitive to matrix effects, mass attenuation and Compton scattering have to be corrected thoroughly in order to derive quantitative values. Examples of process monitoring of advection and diffusion processes with GeoPET illustrate the procedure and the experimental conditions, as well as the benefits and limits of the method.

  1. Florbetapir positron emission tomography and cerebrospinal fluid biomarkers

    PubMed Central

    Hake, Ann; Trzepacz, Paula T.; Wang, Shufang; Yu, Peng; Case, Michael; Hochstetler, Helen; Witte, Michael M.; Degenhardt, Elisabeth K.; Dean, Robert A.

    2015-01-01

    Background We evaluated the relationship between florbetapir-F18 positron emission tomography (FBP PET) and cerebrospinal fluid (CSF) biomarkers. Methods Alzheimer’s Disease Neuroimaging Initiative (ADNI)-GO/2 healthy control (HC), mild cognitive impairment (MCI), and Alzheimer’s disease (AD) dementia subjects with clinical measures and CSF collected ±90 days of FBP PET data were analyzed using correlation and logistic regression. Results In HC and MCI subjects, FBP PET anterior and posterior cingulate and composite standard uptake value ratios correlated with CSF amyloid beta (Aβ1-42) and tau/Aβ1-42 ratios. Using logistic regression, Aβ1-42, total tau (t-tau), phosphorylated tau181P (p-tau), and FBP PET composite each differentiated HC versus AD. Aβ1-42 and t-tau distinguished MCI versus AD, without additional contribution by FBP PET. Total tau and p-tau added discriminative power to FBP PET when classifying HC versus AD. Conclusion Based on cross-sectional diagnostic groups, both amyloid and tau measures distinguish healthy from demented subjects. Longitudinal analyses are needed. PMID:25916563

  2. Proceedings of clinical SPECT (single photon emission computed tomography) symposium

    SciTech Connect

    Not Available

    1986-09-01

    It has been five years since the last in-depth American College of Nuclear Physicians/Society of Nuclear Medicine Symposium on the subject of single photon emission computed tomography (SPECT) was held. Because this subject was nominated as the single most desired topic we have selected SPECT imaging as the basis for this year's program. The objectives of this symposium are to survey the progress of SPECT clinical applications that have taken place over the last five years and to provide practical and timely guidelines to users of SPECT so that this exciting imaging modality can be fully integrated into the evaluation of pathologic processes. The first half was devoted to a consideration of technical factors important in SPECT acquisition and the second half was devoted to those organ systems about which sufficient clinical SPECT imaging data are available. With respect to the technical aspect of the program we have selected the key areas which demand awareness and attention in order to make SPECT operational in clinical practice. These include selection of equipment, details of uniformity correction, utilization of phantoms for equipment acceptance and quality assurance, the major aspect of algorithms, an understanding of filtered back projection and appropriate choice of filters and an awareness of the most commonly generated artifacts and how to recognize them. With respect to the acquisition and interpretation of organ images, the faculty will present information on the major aspects of hepatic, brain, cardiac, skeletal, and immunologic imaging techniques. Individual papers are processed separately for the data base. (TEM)

  3. The Next Generation of Positron Emission Tomography Radiopharmaceuticals in Oncology

    PubMed Central

    Rice, Samuel L.; Roney, Celeste A.; Daumar, Pierre; Lewis, Jason S.

    2015-01-01

    Although 18F-fluorodeoxyglucose (18F-FDG) is still the most widely used positron emission tomography (PET) radiotracer, there are a few well-known limitations to its use. The last decade has seen the development of new PET probes for in vivo visualization of specific molecular targets, along with important technical advances in the production of positron-emitting radionuclides and their related labeling methods. As such, a broad range of new PET tracers are in preclinical development or have recently entered clinical trials. The topics covered in this review include labeling methods, biological targets, and the most recent preclinical or clinical data of some of the next generation of PET radiopharmaceuticals. This review, which is by no means exhaustive, has been separated into sections related to the PET radionuclide used for radiolabeling: fluorine-18, for the labeling of agents such as FACBC, FDHT, choline, and Galacto-RGD; carbon-11, for the labeling of choline; gallium-68, for the labeling of peptides such as DOTATOC and bombesin analogs; and the long-lived radionuclides iodine-124 and zirconium-89 for the labeling of monoclonal antibodies cG250, and J591 and trastuzumab, respectively. PMID:21624561

  4. The next generation of positron emission tomography radiopharmaceuticals in oncology.

    PubMed

    Rice, Samuel L; Roney, Celeste A; Daumar, Pierre; Lewis, Jason S

    2011-07-01

    Although (18)F-fluorodeoxyglucose ((18)F-FDG) is still the most widely used positron emission tomography (PET) radiotracer, there are a few well-known limitations to its use. The last decade has seen the development of new PET probes for in vivo visualization of specific molecular targets, along with important technical advances in the production of positron-emitting radionuclides and their related labeling methods. As such, a broad range of new PET tracers are in preclinical development or have recently entered clinical trials. The topics covered in this review include labeling methods, biological targets, and the most recent preclinical or clinical data of some of the next generation of PET radiopharmaceuticals. This review, which is by no means exhaustive, has been separated into sections related to the PET radionuclide used for radiolabeling: fluorine-18, for the labeling of agents such as FACBC, FDHT, choline, and Galacto-RGD; carbon-11, for the labeling of choline; gallium-68, for the labeling of peptides such as DOTATOC and bombesin analogs; and the long-lived radionuclides iodine-124 and zirconium-89 for the labeling of monoclonal antibodies cG250, and J591 and trastuzumab, respectively.

  5. Imaging pancreatic islet cells by positron emission tomography

    PubMed Central

    Li, Junfeng; Karunananthan, Johann; Pelham, Bradley; Kandeel, Fouad

    2016-01-01

    It was estimated that every year more than 30000 persons in the United States - approximately 80 people per day - are diagnosed with type 1 diabetes (T1D). T1D is caused by autoimmune destruction of the pancreatic islet (β cells) cells. Islet transplantation has become a promising therapy option for T1D patients, while the lack of suitable tools is difficult to directly evaluate of the viability of the grafted islet over time. Positron emission tomography (PET) as an important non-invasive methodology providing high sensitivity and good resolution, is able to accurate detection of the disturbed biochemical processes and physiological abnormality in living organism. The successful PET imaging of islets would be able to localize the specific site where transplanted islets engraft in the liver, and to quantify the level of islets remain alive and functional over time. This information would be vital to establishing and evaluating the efficiency of pancreatic islet transplantation. Many novel imaging agents have been developed to improve the sensitivity and specificity of PET islet imaging. In this article, we summarize the latest developments in carbon-11, fluorine-18, copper-64, and gallium-68 labeled radioligands for the PET imaging of pancreatic islet cells. PMID:27721939

  6. The methodology of TSPO imaging with positron emission tomography.

    PubMed

    Turkheimer, Federico E; Rizzo, Gaia; Bloomfield, Peter S; Howes, Oliver; Zanotti-Fregonara, Paolo; Bertoldo, Alessandra; Veronese, Mattia

    2015-08-01

    The 18-kDA translocator protein (TSPO) is consistently elevated in activated microglia of the central nervous system (CNS) in response to a variety of insults as well as neurodegenerative and psychiatric conditions. It is therefore a target of interest for molecular strategies aimed at imaging neuroinflammation in vivo. For more than 20 years, positron emission tomography (PET) has allowed the imaging of TSPO density in brain using [(11)C]-(R)-PK11195, a radiolabelled-specific antagonist of the TSPO that has demonstrated microglial activation in a large number pathological cohorts. The significant clinical interest in brain immunity as a primary or comorbid factor in illness has sparked great interest in the TSPO as a biomarker and a surprising number of second generation TSPO radiotracers have been developed aimed at improving the quality of TSPO imaging through novel radioligands with higher affinity. However, such major investment has not yet resulted in the expected improvement in image quality. We here review the main methodological aspects of TSPO PET imaging with particular attention to TSPO genetics, cellular heterogeneity of TSPO in brain tissue and TSPO distribution in blood and plasma that need to be considered in the quantification of PET data to avoid spurious results as well as ineffective development and use of these radiotracers.

  7. Simultaneous laser speckle imaging and positron emission tomography

    NASA Astrophysics Data System (ADS)

    Gramer, M.; Feuerstein, D.; Backes, H.; Takagaki, M.; Kumagai, T.; Graf, R.

    2013-06-01

    Complex biological systems often require measurements of multiple parameters with high temporal and spatial resolution. Multimodal approaches and the combination of methods are therefore a powerful tool to address such scientific questions. Laser speckle imaging (LSI) is an optical method that monitors dynamic changes in cortical blood flow (CBF) with high temporal resolution. Positron emission tomography (PET) allows for quantitative imaging of physiological processes and is a gold standard method to determine absolute cerebral blood flow. We developed a setup that allows simultaneous measurement with both modalities. Here, we simultaneously measured CBF with PET and LSI in rats and analyzed how the correlation of PET and LSI is modified when (1) different methods are used for the calculation of speckle inverse correlation time (ICT), (2) speckle data is acquired through thinned or craniectomized skull, (3) influence of surface vessels is removed from the speckle data. For the latter, a method for automated vessel segmentation from LSI data was developed. We obtained the best correlation (R² = 0.890, p<0.001) when correcting for surface vessel structures taking into account the contribution of static scatterers while keeping the coherence factor constant. However, using the originally published relation, which allows a 900 times faster computation of blood flow maps, still provided a good correlation (R2 = 0.879, p<0.001). Given the good correlation between LSI and PET we used our data to calibrate the speckle ICT. Thus, LSI provides CBF in absolute units at high temporal resolution.

  8. Quantifying the limitations of small animal positron emission tomography

    NASA Astrophysics Data System (ADS)

    Oxley, D. C.; Boston, A. J.; Boston, H. C.; Cooper, R. J.; Cresswell, J. R.; Grint, A. N.; Nolan, P. J.; Scraggs, D. P.; Lazarus, I. H.; Beveridge, T. E.

    2009-06-01

    The application of position sensitive semiconductor detectors in medical imaging is a field of global research interest. The Monte-Carlo simulation toolkit GEANT4 [ http://geant4.web.cern.ch/geant4/] was employed to improve the understanding of detailed γ-ray interactions within the small animal Positron Emission Tomography (PET), high-purity germanium (HPGe) imaging system, SmartPET [A.J. Boston, et al., Oral contribution, ANL, Chicago, USA, 2006]. This system has shown promising results in the field of PET [R.J. Cooper, et al., Nucl. Instr. and Meth. A (2009), accepted for publication] and Compton camera imaging [J.E. Gillam, et al., Nucl. Instr. and Meth. A 579 (2007) 76]. Images for a selection of single and multiple point, line and phantom sources were successfully reconstructed using both a filtered-back-projection (FBP) [A.R. Mather, Ph.D. Thesis, University of Liverpool, 2007] and an iterative reconstruction algorithm [A.R. Mather, Ph.D. Thesis, University of Liverpool, 2007]. Simulated data were exploited as an alternative route to a reconstructed image allowing full quantification of the image distortions introduced in each phase of the data processing. Quantifying the contribution of uncertainty in all system components from detector to reconstruction algorithm allows the areas in need of most attention on the SmartPET project and semiconductor PET to be addressed.

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

    PubMed Central

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

    2012-01-01

    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 radiochemistry can lead to the use of smaller quantities of precursors, accelerated reaction rates and easier purification processes with greater yield and higher specific activity of desired probes. Several ‘proof-of-principle’ examples, along with basics of device architecture and operation, and potential limitations of each design are discussed here. Along with the concept of radioisotope distribution from centralized cyclotron facilities to individual imaging centers and laboratories (“decentralized model”), an easy-to-use, standalone, flexible, fully-automated radiochemical microfluidic platform can open up to simpler and more cost-effective procedures for molecular imaging using PET. PMID:20643021

  10. Automated identification of the lung contours in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Nery, F.; Silvestre Silva, J.; Ferreira, N. C.; Caramelo, F. J.; Faustino, R.

    2013-03-01

    Positron Emission Tomography (PET) is a nuclear medicine imaging technique that permits to analyze, in three dimensions, the physiological processes in vivo. One of the areas where PET has demonstrated its advantages is in the staging of lung cancer, where it offers better sensitivity and specificity than other techniques such as CT. On the other hand, accurate segmentation, an important procedure for Computer Aided Diagnostics (CAD) and automated image analysis, is a challenging task given the low spatial resolution and the high noise that are intrinsic characteristics of PET images. This work presents an algorithm for the segmentation of lungs in PET images, to be used in CAD and group analysis in a large patient database. The lung boundaries are automatically extracted from a PET volume through the application of a marker-driven watershed segmentation procedure which is robust to the noise. In order to test the effectiveness of the proposed method, we compared the segmentation results in several slices using our approach with the results obtained from manual delineation. The manual delineation was performed by nuclear medicine physicians that used a software routine that we developed specifically for this task. To quantify the similarity between the contours obtained from the two methods, we used figures of merit based on region and also on contour definitions. Results show that the performance of the algorithm was similar to the performance of human physicians. Additionally, we found that the algorithm-physician agreement is similar (statistically significant) to the inter-physician agreement.

  11. Mediastinal lymph node staging of non-small-cell lung cancer: a prospective comparison of computed tomography and positron emission tomography.

    PubMed

    Scott, W J; Gobar, L S; Terry, J D; Dewan, N A; Sunderland, J J

    1996-03-01

    We compared the abilities of positron emission tomography and computed tomography to detect N2 or N3 lymph node metastases (N2 or N3) in patients with lung cancer. Positron emission tomography detects increased rates of glucose uptake, characteristic of malignant cells. Patients with peripheral tumors smaller than 2 cm and a normal mediastinum were ineligible. All patients underwent computed tomography, positron emission tomography, and surgical staging. The American Thoracic Society lymph node map was used. Computed and positron emission tomographic scans were read by separate radiologists blinded to surgical staging results. Lymph nodes were "positive" by computed tomography if larger than 1.0 cm in short-axis diameter. Standardized uptake values were recorded from areas on positron emission tomography corresponding to those from which biopsy specimens were taken; if greater than 4.2, they were called "positive." Seventy-five lymph node stations (2.8 per patient) were analyzed in 27 patients. Computed tomography incorrectly staged the mediastinum as positive for metastases in three patients and as negative for metastases in three patients. Sensitivity and specificity of computed tomographic scans were 67% and 83%, respectively. Positron emission tomography correctly staged the mediastinum in all 27 patients. When analyzed by individual node station, there were four false positive and four false negative results by computed tomography (sensitivity = 60%, specificity = 93%, positive predictive value = 60%). Positron emission tomography mislabeled one node station as positive (100% sensitive, 98% specific, positive predictive value 91%). The differences were significant when the data were analyzed both for individual lymph node stations (p = 0.039) and for patients (p = 0.031) (McNemar test). Positron emission tomography and computed tomography are more accurate than computed tomography alone in detecting mediastinal lymph node metastases from non-small-cell lung

  12. Co-registration of glucose metabolism with positron emission tomography and vascularity with fluorescent diffuse optical tomography in mouse tumors

    PubMed Central

    2012-01-01

    Background Bimodal molecular imaging with fluorescence diffuse optical tomography (fDOT) and positron emission tomography (PET) has the capacity to provide multiple molecular information of mouse tumors. The objective of the present study is to co-register fDOT and PET molecular images of tumors in mice automatically. Methods The coordinates of bimodal fiducial markers (FM) in regions of detection were automatically detected in planar optical images (x, y positions) in laser pattern optical surface images (z position) and in 3-D PET images. A transformation matrix was calculated from the coordinates of the FM in fDOT and in PET and applied in order to co-register images of mice bearing neuroendocrine tumors. Results The method yielded accurate non-supervised co-registration of fDOT and PET images. The mean fiducial registration error was smaller than the respective voxel sizes for both modalities, allowing comparison of the distribution of contrast agents from both modalities in mice. Combined imaging depicting tumor metabolism with PET-[18 F]2-deoxy-2-fluoro-d-glucose and blood pool with fDOT demonstrated partial overlap of the two signals. Conclusions This automatic method for co-registration of fDOT with PET and other modalities is efficient, simple and rapid, opening up multiplexing capacities for experimental in vivo molecular imaging. PMID:22564761

  13. Image reconstruction of single photon emission computed tomography (SPECT) on a pebble bed reactor (PBR) using expectation maximization and exact inversion algorithms: Comparison study by means of numerical phantom

    NASA Astrophysics Data System (ADS)

    Razali, Azhani Mohd; Abdullah, Jaafar

    2015-04-01

    Single Photon Emission Computed Tomography (SPECT) is a well-known imaging technique used in medical application, and it is part of medical imaging modalities that made the diagnosis and treatment of disease possible. However, SPECT technique is not only limited to the medical sector. Many works are carried out to adapt the same concept by using high-energy photon emission to diagnose process malfunctions in critical industrial systems such as in chemical reaction engineering research laboratories, as well as in oil and gas, petrochemical and petrochemical refining industries. Motivated by vast applications of SPECT technique, this work attempts to study the application of SPECT on a Pebble Bed Reactor (PBR) using numerical phantom of pebbles inside the PBR core. From the cross-sectional images obtained from SPECT, the behavior of pebbles inside the core can be analyzed for further improvement of the PBR design. As the quality of the reconstructed image is largely dependent on the algorithm used, this work aims to compare two image reconstruction algorithms for SPECT, namely the Expectation Maximization Algorithm and the Exact Inversion Formula. The results obtained from the Exact Inversion Formula showed better image contrast and sharpness, and shorter computational time compared to the Expectation Maximization Algorithm.

  14. Image reconstruction of single photon emission computed tomography (SPECT) on a pebble bed reactor (PBR) using expectation maximization and exact inversion algorithms: Comparison study by means of numerical phantom

    SciTech Connect

    Razali, Azhani Mohd Abdullah, Jaafar

    2015-04-29

    Single Photon Emission Computed Tomography (SPECT) is a well-known imaging technique used in medical application, and it is part of medical imaging modalities that made the diagnosis and treatment of disease possible. However, SPECT technique is not only limited to the medical sector. Many works are carried out to adapt the same concept by using high-energy photon emission to diagnose process malfunctions in critical industrial systems such as in chemical reaction engineering research laboratories, as well as in oil and gas, petrochemical and petrochemical refining industries. Motivated by vast applications of SPECT technique, this work attempts to study the application of SPECT on a Pebble Bed Reactor (PBR) using numerical phantom of pebbles inside the PBR core. From the cross-sectional images obtained from SPECT, the behavior of pebbles inside the core can be analyzed for further improvement of the PBR design. As the quality of the reconstructed image is largely dependent on the algorithm used, this work aims to compare two image reconstruction algorithms for SPECT, namely the Expectation Maximization Algorithm and the Exact Inversion Formula. The results obtained from the Exact Inversion Formula showed better image contrast and sharpness, and shorter computational time compared to the Expectation Maximization Algorithm.

  15. Assessment of patient selection criteria for quantitative imaging with respiratory-gated positron emission tomography.

    PubMed

    Bowen, Stephen R; Pierce, Larry A; Alessio, Adam M; Liu, Chi; Wollenweber, Scott D; Stearns, Charles W; Kinahan, Paul E

    2014-07-01

    The objective of this investigation was to propose techniques for determining which patients are likely to benefit from quantitative respiratory-gated imaging by correlating respiratory patterns to changes in positron emission tomography (PET) metrics. Twenty-six lung and liver cancer patients underwent PET/computed tomography exams with recorded chest/abdominal displacements. Static and adaptive amplitude-gated [[Formula: see text

  16. 77 FR 71802 - Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-04

    ... HUMAN SERVICES Food and Drug Administration Guidance on Investigational New Drug Applications for... ``Investigational New Drug Applications for Positron Emission Tomography (PET) Drugs.'' The guidance is intended to assist manufacturers of PET drugs in submitting investigational new drug applications (INDs)....

  17. Clinical positron emission tomography/magnetic resonance imaging applications.

    PubMed

    von Schulthess, Gustav K; Kuhn, Felix Pierre; Kaufmann, Philipp; Veit-Haibach, Patrick

    2013-01-01

    Although clinical positron emission tomography (PET)/computed tomography (CT) applications were obvious and have completely replaced PET in oncology, clinical applications of PET/magnetic resonance (MR) are currently not clearly defined. This is due to the lack of clinical data, which is mainly because PET/MR technology is not clinically mature at this point. Open issues are technical and concern ease of obtaining PET attenuation correction maps, dealing with, for example, MR surface coil metal in the PET field-of-view and appropriate workflows leading to a cost-effective examination. All issues can be circumvented by using a shuttle-connected PET/CT-MR system, but the penalty is that simultaneous PET and MR imaging are not possible and potential motion between examinations may occur. Clinically, some systems installed worldwide start to have a reasonable bulk of clinical data. Preliminary results suggest that in oncology, PET/MR may have advantages over PET/CT in head and neck imaging. In liver imaging, more PET-positive lesions are seen on MR than on CT, but that does not mean that PET/MR is superior to PET/CT. Possibly in some settings where a contrast-enhanced PET/CT is needed to be diagnostic, PET/MR can be done without contrast media. Although PET/CT has virtually no role in brain imaging, this may be an important domain for PET/MR, particularly in dementia imaging. The role of PET/MR in the heart is as yet undefined, and much research will have to be done to elucidate this role. At this point, it is also not clear where the simultaneity afforded by a fully integrated PET/MR is really needed. Sequential data acquisition even on separate systems and consecutive software image fusion may well be appropriate. With the increasing installed base of systems, clinical data will be forthcoming and define more clearly where there is clinical value in PET/MR at an affordable price. PMID:23178084

  18. [18F] fluoromisonidazole and [18F] fluorodeoxyglucose positron emission tomography in response evaluation after chemo-/radiotherapy of non-small-cell lung cancer: a feasibility study

    PubMed Central

    Gagel, Bernd; Reinartz, Patrick; Demirel, Cengiz; Kaiser, Hans J; Zimny, Michael; Piroth, Marc; Pinkawa, Michael; Stanzel, Sven; Asadpour, Branka; Hamacher, Kurt; Coenen, Heinz H; Buell, Ulrich; Eble, Michael J

    2006-01-01

    Background Experimental and clinical evidence suggest that hypoxia in solid tumours reduces their sensitivity to conventional treatment modalities modulating response to ionizing radiation or chemotherapeutic agents. The aim of the present study was to show the feasibility of determining radiotherapeutically relevant hypoxia and early tumour response by ([18F] Fluoromisonidazole (FMISO) and [18F]-2-fluoro-2'-deoxyglucose (FDG) PET. Methods Eight patients with non-small-cell lung cancer underwent PET scans. Tumour tissue oxygenation was measured with FMISO PET, whereas tumour glucose metabolism was measured with FDG PET. All PET studies were carried out with an ECAT EXACT 922/47® scanner with an axial field of view of 16.2 cm. FMISO PET consisted of one static scan of the relevant region, performed 180 min after intravenous administration of the tracer. The acquisition and reconstruction parameters were as follows: 30 min emission scanning and 4 min transmission scanning with 68-Ge/68-Ga rod sources. The patients were treated with chemotherapy, consisting of 2 cycles of gemcitabine (1200 mg/m2) and vinorelbine (30 mg/m2) followed by concurrent radio- (2.0 Gy/d; total dose 66.0 Gy) and chemotherapy with gemcitabine (300–500 mg/m2) every two weeks. FMISO PET and FDG PET were performed in all patients 3 days before and 14 days after finishing chemotherapy. Results FMISO PET allowed for the qualitative and quantitative definition of hypoxic sub-areas which may correspond to a localization of local recurrences. In addition, changes in FMISO and FDG PET measure the early response to therapy, and in this way, may predict freedom from disease, as well as overall survival. Conclusion These preliminary results warrant validation in larger trials. If confirmed, several novel treatment strategies may be considered, including the early use of PET to evaluate the effectiveness of the selected therapy. PMID:16515707

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

    SciTech Connect

    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.

  20. Hemispheric encoding/retrieval asymmetry in episodic memory: positron emission tomography findings.

    PubMed Central

    Tulving, E; Kapur, S; Craik, F I; Moscovitch, M; Houle, S

    1994-01-01

    Data are reviewed from positron emission tomography studies of encoding and retrieval processes in episodic memory. These data suggest a hemispheric encoding/retrieval asymmetry model of prefrontal involvement in encoding and retrieval of episodic memory. According to this model, the left and right prefrontal lobes are part of an extensive neuronal network that subserves episodic remembering, but the two prefrontal hemispheres play different roles. Left prefrontal cortical regions are differentially more involved in retrieval of information from semantic memory and in simultaneously encoding novel aspects of the retrieved information into episodic memory. Right prefrontal cortical regions, on the other hand, are differentially more involved in episodic memory retrieval. PMID:8134342

  1. Positron emission tomography: a first-hand experience.

    PubMed

    Traylor, J

    2000-01-01

    In July 1999, the University of Kansas Hospital installed a positron emission tomography (PET) scanner and added PET to the imaging technologies it offers patients and physicians. The new service is managed by the nuclear medicine section in the department of radiology. Plans are being implemented now to install a cyclotron in March 2000. Prior to installation of the scanner, a radiation area survey was performed in the space being considered for the PET unit. We also needed to address other critical considerations, including the manufacturer's requirements for construction of the scanner room, special electrical needs, and how the system would connect to our existing information network. It is important to work closely with your chief financial officer and chief operations officer from the beginning of the purchasing process so that these administrators have up-to-date, supportive information about PET and the progress of the installation. We made use of a variety of promotional techniques to market the new service, including broadcast e-mail, an open house for potential referring physicians, postings on the nuclear medicine Web site and communication through the local media. We also worked with the major insurance providers that utilize our hospital to educate them about PET and its benefits. In addition, we trained our own billing staff about procedures that optimize reimbursement for PET. In March 2000, University of Kansas Hospital will install the first cyclotron in the state, enabling us to generate the drugs used for PET scanning and potentially to add targets for research PET radiopharmaceuticals. PMID:10787761

  2. Determination of Internal Target Volume From a Single Positron Emission Tomography/Computed Tomography Scan in Lung Cancer

    SciTech Connect

    Chang Guoping; Chang Tingting; Pan Tinsu; Clark, John W.; Mawlawi, Osama R.

    2012-05-01

    Purpose: The use of four-dimensional computed tomography (4D-CT) to determine the tumor internal target volume (ITV) is usually characterized by high patient radiation exposure. The objective of this study was to propose and evaluate an approach that relies on a single static positron emission tomography (PET)/CT scan to determine the ITV, thereby eliminating the need for 4D-CT and thus reduce patient radiation dose. Methods and Materials: The proposed approach is based on the concept that the observed PET image is the result of a joint convolution of an ideal PET image (free from motion and partial volume effect) with a motion-blurring kernel (MBK) and partial volume effect. In this regard, the MBK and tumor ITV are then estimated from the deconvolution of this joint model. To test this technique, phantom and patient studies were performed using different sphere/tumor sizes and motion trajectories. In all studies, a 4D-CT and a PET/CT image of the sphere/tumor were acquired. The ITV from the proposed technique was then compared to the maximum intensity projection (MIP) volume of the 4D-CT images. A Dice coefficient of the two volumes was calculated to represent the similarity between the two ITVs. Results: The average ITVs of the proposed technique were 97.2% {+-} 0.3% and 81.0% {+-} 16.7% similar to the MIP volume in the phantom and patient studies, respectively. The average dice coefficients were 0.87 {+-} 0.05 and 0.73 {+-} 0.16, respectively, for the two studies. Conclusion: Using the proposed approach, a single static PET/CT scan has the potential to replace a 4D-CT to determine the tumor ITV. This approach has the added advantage of reducing patient radiation exposure and determining the tumor MBK compared to 4D-CT/MIP-CT.

  3. Spectrum of fluorodeoxyglucose-positron emission tomography/computed tomography and magnetic resonance imaging findings of ovarian tumors.

    PubMed

    Kitajima, Kazuhiro; Ueno, Yoshiko; Maeda, Tetsuo; Murakami, Koji; Kaji, Yasushi; Kita, Masato; Suzuki, Kayo; Sugimura, Kazuro

    2011-11-01

    The purpose of this article is to review fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI) findings in a variety of benign, malignant, and borderline malignant ovarian tumors. It is advantageous to become familiar with the wide variety of FDG-PET/CT findings of this entity. Benign ovarian tumors generally have faint uptake, whereas endometriomas, fibromas, and teratomas show mild to moderate uptake. Malignant ovarian tumors generally have intense uptake, whereas tumors with a small solid component often show minimal uptake.

  4. Metastatic superscan in prostate carcinoma on gallium-68-prostate-specific membrane antigen positron emission tomography/computed tomography scan

    PubMed Central

    Agarwal, Krishan Kant; Tripathi, Madhavi; Kumar, Rajeev; Bal, Chandrasekhar

    2016-01-01

    We describe the imaging features of a metastatic superscan on gallium-68 Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as gallium-68-prostate-specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) imaging. 68Ga-PSMA is novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. This patient had a superscan of metastases on conventional bone scintigraphy and was referred for 68Ga-PSMA PET/CT to evaluate the feasibility of 177Lu-PSMA therapy. PMID:27095868

  5. Clinical usefulness of post-operative 18F-fluorodeoxyglucose positron emission tomography-computed tomography in canine hemangiosarcoma

    PubMed Central

    Lee, Gahyun; Kwon, Seong Young; Son, Kyuyeol; Park, Seungjo; Lee, Ju-hwan; Cho, Kyoung-Oh; Min, Jung-Joon

    2016-01-01

    This report describes the usefulness of positron emission tomography-computed tomography (PET-CT) for evaluating recurrent or residual tumors following surgery. CT and 18F-fluorodeoxyglucose PET-CT were pre- and post-operatively applied to multiple masses in a dog with hemangiosarcoma. The distinction between the left subcutaneous mass and the peritoneum was clarified on pre-operative CT examination, and malignancy was suspected based on PET-CT. A recurrent or residual tumor in the left subcutaneous region was suspected on post-operative PET-CT, and confirmed through histopathologic examination. PMID:26645332

  6. Evaluation of Shoulder Disorders by 2-[F-18]-fluoro-2-deoxy-D-glucose Positron Emission Tomography and Computed Tomography

    PubMed Central

    Lee, Sang Hong; Park, Sung Yong; Yu, Jae Cheol; Gorthi, Venkat

    2010-01-01

    Background Although flourine-18-flourodeoxyglucose (FDG) positron emission tomography (PET) has a limitation for localizing anatomical structures, combining it with computed tomography (CT) has made it more efficient for overcoming such limitations. This study aims to evaluate the efficacy of PET/CT for evaluating diseases of the shoulder. Methods Retrospective examination was performed on 25 patients who underwent FDG-PET/CT scanning. All the patients were over 60 years of age, and they were evaluated both clinically and radiologically for shoulder pain. The study period was from May, 2006 to May, 2008. One of the patients had metastatic lesion in a shoulder and this patient was excluded from the study, so the total number of subjects in the study was finally 24 patients. Results PET/CT showed 67% sensitivity, 73% specificity, a positive predictive value of 60%, a negative predictive value of 79%, 27% false positivity and 33% false negativity concerning shoulder pain. PET/CT showed negative finding in 4 cases that were successfully treated by operative treatment (rotator cuff tear [RCT], 3 cases; impingement syndrome, 1 case). Negative findings were also noted in 6 cases in which the pain subsided after conservative treatment (RCT, 1 case; suspected RCT, 2 cases; impingement syndrome, 3 cases). All the patients with osteoarthritis and rheumatoid arthritis had positive findings on PET/CT scanning. Conclusions PET/CT is a useful adjunct to the existing imaging modalities to assess functional and pathophysiologic processes and at a very early stage, and so PET/CT can help physicians make better preoperative and postoperative decisions on treatment. PMID:20808588

  7. Carbon nanotube based microfocus field emission x-ray source for microcomputed tomography

    SciTech Connect

    Liu Zejian; Yang Guang; Lee, Yueh Z.; Bordelon, David; Lu Jianping; Zhou, Otto

    2006-09-04

    Microcomputed tomography is now widely used for in vivo small animal imaging for cancer studies. Achieving high imaging quality of live objects requires the x-ray source to have both high spatial and temporal resolutions. Preliminary studies have shown that carbon nanotube (CNT) based field emission x-ray source has significant intrinsic advantages over the conventional thermionic x-ray tube including better temporal resolution and programmability. Here we report the design and characterization of a CNT based field emission x-ray source that also affords a high spatial resolution. The device uses modified asymmetric Einzel lenses for electron focusing and an elliptical shaped CNT cathode patterned by photolithography. Stable and small isotropic x-ray focal spot sizes were obtained.

  8. Role of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Cytologically Indeterminate Thyroid Nodules

    PubMed Central

    Buyukdereli, Gulgun; Aktar, Yasemin; Kara, Ertan; Uguz, Aysun; Sonmez, Husnu

    2016-01-01

    Background: Thyroid nodules with indeterminate fine-needle aspiration biopsy (FNAB) results remain a diagnostic dilemma, because 70 - 85% of these nodules have been found to be benign after thyroid surgery. Objectives: The purpose of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the preoperative diagnosis of cytologically indeterminate nodules. Patients and Methods: Forty-six patients were included in this study. These individuals had undergone FDG PET/CTs for the preoperative evaluation of thyroid nodules with indeterminate FNAB results. The results of the preoperative PET/CT scans were compared with the postoperative pathological results and statistically analyzed. Results: Of the 46 patients included in our study, the histopathology of the surgical specimens revealed thyroid cancer in 17 individuals (37%, 17/46). The PET/CT scan showed a positive result in 27 patients. Of these, 16 patients (59.3%) were found to have thyroid carcinomas. In addition, the PET/CT scan was considered to be negative in 19 patients, 18 (94.7%) of whom had benign lesions. For the detection of malignant lesions, the values for the sensitivity and specificity, and the positive predictive and negative predictive values were 94%, 62%, 59%, and 95%, respectively. Conclusion: The FDG PET/CT showed a high sensitivity and a high negative predictive value for identifying malignancies in thyroid nodules with indeterminate FNAB results. Therefore, the FDG PET/CT may be a helpful tool in the clinical management of these nodules. When an FDG positive lesion is detected, further examination is recommended. PMID:27110335

  9. Contrast-enhanced [18 F] fluorodeoxyglucose-positron emission tomography/computed tomography in clinical oncology: tumor-, site-, and question-based comparison with standard positron emission tomography/computed tomography

    PubMed Central

    2014-01-01

    Background The present study aimed to evaluate the added value of contrast-enhanced computed tomography (ceCT) in comparison to standard, non-enhanced CT in the context of a combined positron emission tomography (PET)/CT examination by means of a tumor-, site-, and clinical question-based approach. Methods Analysis was performed in 202 patients undergoing PET/CT consisting of a multiphase CT protocol followed by a whole-body PET. The Cochran Q test was performed, followed by a multiple comparisons correction (McNemar test and Bonferroni adjustment), to compare standard and contrast-enhanced PET (cePET/CT). Histopathology or clinical-radiologic follow-up greater than 1 year was used as a reference. Results cePET/CT showed significantly different results with respect to standard PET/CT in head and neck and gastrointestinal cancer (P = 0.02 and 0.0002, respectively), in the evaluation of lesions located in the abdomen (P = 0.009), and in the context of disease restaging (P = 0.003). In all these clinical scenarios, adding ceCT resulted in a distinct benefit, by yielding a higher percentage of change in patient management. Conclusion These data strongly underline the importance of strictly selecting patients for the combined exam. In particular, patient selection should not be driven solely by mere tumor classification, but should also account for the clinical question and the anatomical location of the neoplastic disease, which can significantly impact patient management. PMID:25609564

  10. Absolute quantitation of iodine-123 epidepride kinetics using single-photon emission tomography: comparison with carbon-11 epidepride and positron emission tomography.

    PubMed

    Almeida, P; Ribeiro, M J; Bottlaender, M; Loc'h, C; Langer, O; Strul, D; Hugonnard, P; Grangeat, P; Mazière, B; Bendriem, B

    1999-12-01

    Epidepride labelled with iodine-123 is a suitable probe for the in vivo imaging of striatal and extrastriatal dopamine D2 receptors using single-photon emission tomography (SPET). Recently, this molecule has also been labelled with carbon-11. The goal of this work was to develop a method allowing the in vivo quantification of radioactivity uptake in baboon brain using SPET and to validate it using positron emission tomography (PET). SPET studies were performed in Papio anubis baboons using 123I-epidepride. Emission and transmission measurements were acquired on a dual-headed system with variable head angulation and low-energy ultra-high resolution (LEUHR) collimation. The imaging protocol consisted of one transmission measurement (24 min, heads at 90 degrees), obtained with two sliding line sources of gadolinium-153 prior to injection of 0.21-0.46 GBq of 123I-epidepride, and 12 emission measurements starting 5 min post injection. For scatter correction (SC) we used a dual-window method adapted to 123I. Collimator blurring correction (CBC) was done by deconvolution in Fourier space and attenuation correction (AT) was applied on a preliminary (CBC) filtered back-projection reconstruction using 12 iterations of a preconditioned, regularized minimal residual algorithm. For each reconstruction, a calibration factor was derived from a uniform cylinder filled with a 123I solution of a known radioactivity concentration. Calibration and baboon images were systematically built with the same reconstruction parameters. Uncorrected (UNC) and (AT), (SC + AT) and (SC + CBC + AT) corrected images were compared. PET acquisitions using 0.11-0.44 GBq of 11C-epidepride were performed on the same baboons and used as a reference. The radioactive concentrations expressed in percent of the injected dose per 100 ml (% ID/100 ml) obtained after (SC + CBC + AT) in SPET are in good agreement with those obtained with PET and 11C-epidepride. A method for the in vivo absolute quantitation of 123

  11. Disproportionate Reduction of Serotonin Transporter May Predict the Response and Adherence to Antidepressants in Patients with Major Depressive Disorder: A Positron Emission Tomography Study with 4-[18F]-ADAM

    PubMed Central

    Yeh, Yi-Wei; Ho, Pei-Shen; Kuo, Shin-Chang; Chen, Chun-Yen; Liang, Chih-Sung; Yen, Che-Hung; Huang, Chang-Chih; Ma, Kuo-Hsing; Shiue, Chyng-Yann; Huang, Wen-Sheng; Shyu, Jia-Fwu; Wan, Fang-Jung; Lu, Ru-Band

    2015-01-01

    Background: Many lines of evidence suggest the role of serotonin transporter (SERT)-mediated reuptake of serotonin in the pathophysiology and treatment of major depressive disorder (MDD). This study aimed to examine whether the pretreatment of SERT binding potential or SERT binding ratio between terminal projection regions relative to the midbrain raphe nuclei was associated with treatment outcomes to SERT-targeted antidepressants. Methods: We recruited 39 antidepressant-naïve patients with MDD and 39 heathy controls. Positron emission tomography with N,N-dimethyl-2-(2-amino-4-[18F]fluorophenylthio)benzylamine (4-[18F]-ADAM) was used to measure in vivo SERT availability prior to antidepressant treatment. The 21-item Hamilton Depression Rating Scale (HDRS) was use to assess the severity of depression from baseline to week 6. All the patients with MDD had HDRS scores of 18 or more. Results: Pretreatment SERT binding in the thalamus and striatum positively correlated with an early reduction in HDRS scores at week 3. Nonresponders and dropout patients showed a proportionate reduction in SERT binding in the terminal projection regions and midbrain compared to healthy controls. In contrast, a disproportionate reduction in SERT binding in the terminal projection regions relative to midbrain was observed in responders. Conclusions: The results of this study suggested that a disproportionate reduction in SERT binding between terminal projection regions and midbrain may predict better treatment outcomes in patients with MDD. PMID:25568284

  12. 18F-fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma

    PubMed Central

    Li, Xiao-Feng; Fu, Qiang; Dong, You-Wen; Liu, Jian-Jing; Song, Xiu-Yu; Dai, Dong; Zuo, Cong; Xu, Wen-Gui

    2016-01-01

    AIM To compare 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma. METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent 18F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions, including FDG avidity, pattern (focal/diffuse), and intensity [maximal standard uptake value: (SUVmax)]. The correlation of SUVmax with gastric clinicopathological variables was investigated by χ2 test, and receiver-operating characteristic (ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients (94.23%) with gastric lymphoma and 65 patients (89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type I and type II lesions, whereas gastric carcinoma patients mainly had type III lesions. The SUVmax (13.39 ± 9.24 vs 8.35 ± 5.80, P < 0.001) and SUVmax/THKmax (maximal thickness) (7.96 ± 4.02 vs 4.88 ± 3.32, P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone. CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma, which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma. PMID:27678362

  13. 18F-fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma

    PubMed Central

    Li, Xiao-Feng; Fu, Qiang; Dong, You-Wen; Liu, Jian-Jing; Song, Xiu-Yu; Dai, Dong; Zuo, Cong; Xu, Wen-Gui

    2016-01-01

    AIM To compare 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma. METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent 18F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions, including FDG avidity, pattern (focal/diffuse), and intensity [maximal standard uptake value: (SUVmax)]. The correlation of SUVmax with gastric clinicopathological variables was investigated by χ2 test, and receiver-operating characteristic (ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients (94.23%) with gastric lymphoma and 65 patients (89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type I and type II lesions, whereas gastric carcinoma patients mainly had type III lesions. The SUVmax (13.39 ± 9.24 vs 8.35 ± 5.80, P < 0.001) and SUVmax/THKmax (maximal thickness) (7.96 ± 4.02 vs 4.88 ± 3.32, P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone. CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma, which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma.

  14. Computed tomography and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography findings in adrenal candidiasis and histoplasmosis: two cases.

    PubMed

    Altinmakas, Emre; Guo, Ming; Kundu, Uma R; Habra, Mouhammed Amir; Ng, Chaan

    2015-01-01

    We report the contrast-enhanced computed tomography (CT) and (18)F-fluorodeoxyglucose positron emission tomography findings in adrenal histoplasmosis and candidiasis. Both demonstrated bilateral hypermetabolic heterogeneous adrenal masses with limited wash-out on delayed CT. Adrenal candidiasis has not been previously reported, nor have the CT wash-out findings in either infection. The adrenal imaging findings are indistinguishable from malignancy, which is more common; but in this setting, physicians should be alert to the differential diagnosis of fungal infections, since it can be equally deadly.

  15. Catecholamine stimulation, substrate competition, and myocardial glucose uptake in conscious dogs assessed with positron emission tomography.

    PubMed

    Merhige, M E; Ekas, R; Mossberg, K; Taegtmeyer, H; Gould, K L

    1987-11-01

    Uptake of radiolabelled deoxyglucose out of proportion to reduced coronary flow demonstrated by positron emission tomography has been used to identify reversibly ischemic, viable myocardium. For this concept to be applied reliably in the clinical setting, factors that may depress glucose availability independent of tissue viability, such as adrenergic stimulation and substrate competition, must be examined. Accordingly, we studied the effect of catecholamine stimulation by dopamine on myocardial glucose uptake in vivo using chronically instrumented, intact dogs and positron emission tomography. We measured myocardial activity of [2-18F]-2-deoxyglucose (FDG) and 82Rb in glucose-loaded animals randomly studied during dopamine infusion, during insulin infusion, and then during their combined infusion. Myocardial FDG uptake was significantly decreased when animals were treated with dopamine, compared with treatment in the same animals with insulin. When insulin was added to the dopamine infusion, myocardial FDG uptake was restored. In contrast, myocardial activity of 82Rb, which is taken up in proportion to coronary flow, was similar under all three experimental conditions. Plasma glucose, free fatty acid, and lactate concentrations were determined before and during each infusion. The depression of myocardial FDG activity seen during dopamine infusion and its reversal with addition of insulin can be explained on the basis of effects of these hormones on substrate availability and competition.

  16. Positron Emission Tomography Imaging Using Radiolabeled Inorganic Nanomaterials

    PubMed Central

    Sun, Xiaolian; Cai, Weibo; Chen, Xiaoyuan

    2015-01-01

    CONSPECTUS Positron emission tomography (PET) is a radionuclide imaging technology that plays an important role in preclinical and clinical research. With administration of a small amount of radiotracer, PET imaging can provide a noninvasive, highly sensitive, and quantitative readout of its organ/tissue targeting efficiency and pharmacokinetics. Various radiotracers have been designed to target specific molecular events. Compared with antibodies, proteins, peptides, and other biologically relevant molecules, nanoparticles represent a new frontier in molecular imaging probe design, enabling the attachment of different imaging modalities, targeting ligands, and therapeutic payloads in a single vector. We introduce the radiolabeled nanoparticle platforms that we and others have developed. Due to the fundamental differences in the various nanoparticles and radioisotopes, most radiolabeling methods are designed case-by-case. We focus on some general rules about selecting appropriate isotopes for given types of nanoparticles, as well as adjusting the labeling strategies according to specific applications. We classified these radiolabeling methods into four categories: (1) complexation reaction of radiometal ions with chelators via coordination chemistry; (2) direct bombardment of nanoparticles via hadronic projectiles; (3) synthesis of nanoparticles using a mixture of radioactive and nonradioactive precursors; (4) chelator-free postsynthetic radiolabeling. Method 1 is generally applicable to different nanomaterials as long as the surface chemistry is well-designed. However, the addition of chelators brings concerns of possible changes to the physicochemical properties of nanomaterials and detachment of the radiometal. Methods 2 and 3 have improved radiochemical stability. The applications are, however, limited by the possible damage to the nanocomponent caused by the proton beams (method 2) and harsh synthetic conditions (method 3). Method 4 is still in its infancy

  17. Positron emission tomography study on pancreatic somatostatin receptors in normal and diabetic rats with {sup 68}Ga-DOTA-octreotide: A potential PET tracer for beta cell mass measurement

    SciTech Connect

    Sako, Takeo; Hasegawa, Koki; Nishimura, Mie; Kanayama, Yousuke; Wada, Yasuhiro; Hayashinaka, Emi; Cui, Yilong; Kataoka, Yosky; Senda, Michio; Watanabe, Yasuyoshi

    2013-12-06

    Highlights: •PET images showed high uptake of {sup 68}Ga-DOTA-octreotide in the normal pancreas. •{sup 68}Ga-DOTA-octreotide specifically binds to somatostatin receptors in the pancreas. •The pancreatic uptake of {sup 68}Ga-DOTA-octreotide was decreased in the diabetic rats. •{sup 68}Ga-DOTA-octreotide could be a candidate PET probe to measure the beta cell mass. -- Abstract: Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, and the loss or dysfunction of pancreatic beta cells has been reported before the appearance of clinical symptoms and hyperglycemia. To evaluate beta cell mass (BCM) for improving the detection and treatment of DM at earlier stages, we focused on somatostatin receptors that are highly expressed in the pancreatic beta cells, and developed a positron emission tomography (PET) probe derived from octreotide, a metabolically stable somatostatin analog. Octreotide was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), a chelating agent, and labeled with {sup 68}Gallium ({sup 68}Ga). After intravenous injection of {sup 68}Ga-DOTA-octreotide, a 90-min emission scan of the abdomen was performed in normal and DM model rats. The PET studies showed that {sup 68}Ga-DOTA-octreotide radioactivity was highly accumulated in the pancreas of normal rats and that the pancreatic accumulation was significantly reduced in the rats administered with an excess amount of unlabeled octreotide or after treatment with streptozotocin, which was used for the chemical induction of DM in rats. These results were in good agreement with the ex vivo biodistribution data. These results indicated that the pancreatic accumulation of {sup 68}Ga-DOTA-octreotide represented specific binding to the somatostatin receptors and reflected BCM. Therefore, PET imaging with {sup 68}Ga-DOTA-octreotide could be a potential tool for evaluating BCM.

  18. P-glycoprotein mediated interaction between (R)-[11C]verapamil and tariquidar at the human blood-brain barrier studied with positron emission tomography, a comparison with rat data

    PubMed Central

    Bauer, Martin; Zeitlinger, Markus; Karch, Rudolf; Matzneller, Peter; Stanek, Johann; Jäger, Walter; Böhmdorfer, Michaela; Wadsak, Wolfgang; Mitterhauser, Markus; Bankstahl, Jens P.; Löscher, Wolfgang; Koepp, Matthias; Müller, Markus; Langer, Oliver

    2013-01-01

    Using positron emission tomography (PET) imaging we assessed in vivo the interaction between a microdose of (R)-[11C]verapamil, a P-glycoprotein (Pgp) substrate, and escalating doses of the Pgp inhibitor tariquidar (3, 4, 6 and 8 mg/kg) at the blood-brain barrier (BBB) of healthy human subjects. We compared the dose-response relationship of tariquidar in humans with data obtained in rats using similar methodology. Tariquidar was equipotent in humans and rats to increase (R)-[11C]verapamil brain uptake, expressed as whole brain volume of distribution (VT), with very similar half-maximum effect concentrations. Both in humans and rats, brain VTs approached plateau levels at tariquidar plasma concentrations >1,000 ng/mL. However, Pgp inhibition in humans only led to 2.7-fold increase in brain VT relative to baseline scans without tariquidar compared to 11.0-fold in rats. The results of this translational study add to the accumulating evidence of marked species-dependent differences in Pgp expression and functionality at the BBB. PMID:22166851

  19. Radiation Dose from Whole-Body F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Nationwide Survey in Korea

    PubMed Central

    2016-01-01

    The purpose of this study was to estimate average radiation exposure from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) examinations and to analyze possible factors affecting the radiation dose. A nation-wide questionnaire survey was conducted involving all institutions that operate PET/CT scanners in Korea. From the response, radiation doses from injected FDG and CT examination were calculated. A total of 105 PET/CT scanners in 73 institutions were included in the analysis (response rate of 62.4%). The average FDG injected activity was 310 ± 77 MBq and 5.11 ± 1.19 MBq/kg. The average effective dose from FDG was estimated to be 5.89 ± 1.46 mSv. The average CT dose index and dose-length product were 4.60 ± 2.47 mGy and 429.2 ± 227.6 mGy∙cm, which corresponded to 6.26 ± 3.06 mSv. The radiation doses from FDG and CT were significantly lower in case of newer scanners than older ones (P < 0.001). Advanced PET technologies such as time-of-flight acquisition and point-spread function recovery were also related to low radiation dose (P < 0.001). In conclusion, the average radiation dose from FDG PET/CT is estimated to be 12.2 mSv. The radiation dose from FDG PET/CT is reduced with more recent scanners equipped with image-enhancing algorithms. PMID:26908992

  20. Line emission tomography for CDX-U using filtered diodes

    SciTech Connect

    Stutman, D.; Menard, J.; Hwang, Y.S.; Choe, W.; Ono, M.; Finkenthal, M.; Soukhanovskii, V.; May, M.J.; Regan, S.P.; Moos, H.W.

    1997-01-01

    Electron density and temperature in the CDX-U low aspect ratio tokamak are too low to allow observation of fast magnetohydrodynamic activity using soft x-ray continuum emission. However, spectroscopic measurements show that extreme ultraviolet (XUV) line emission of intrinsic impurities is bright enough to observe such activity. In addition, a fast monitoring system for local temperature changes in the plasma core is required for planned auxiliary heating experiments. We present a spectrally resolved tomographic system for fast imaging of OVI 2s{endash}np, 2p{endash}nd (n{ge}3), CV 1s{sup 2}{endash}1s2p and CVI 1s{endash}2p XUV transitions. Using this emission, we can study both core and edge MHD activity, while the CVI to CV intensity ratio can indicate local changes in electron temperature. To achieve maximal throughput together with the needed spectral resolution, we use arrays of surface barrier diodes filtered with bandpass elemental filters. Using M edge filters (Zr, Pd, and Ag), we achieve both good discrimination between the above charge states and large transmission at the wavelengths of interest. Preliminary results obtained from CDX-U are presented. {copyright} {ital 1997 American Institute of Physics.}

  1. Three dimensional quantification of left ventricular wall motion by ECG-gated blood pool emission tomography

    SciTech Connect

    Underwood, S.R.; Walton, S.; Laming, P.J.; Jarritt, P.H.; Ell, P.J.; Emanuel, R.W.; Swanton, R.H.

    1985-05-01

    ECG-gated blood pool emission tomography is a relatively new technique, and this study establishes a simple method for displaying the three dimensional data obtained, determines a normal range for ejection fraction in all regions of the left ventricle, and compares wall motion in abnormal subjects with that determined by X-ray contrast ventriculography. The short axis sections dividing the ventricle in slices from apex to base, were used to calculate ejection fraction for all parts of the ventricle and the results were plotted on a single colour coded circular image. The apex was represented in the centre, the base around the circumference, and all other parts of the ventricle were represented in between. The image was divided into 15 segments, and normal segmental ejection fraction was defined as within two standard deviations of the mean in a group of 10 normal subjects. In 25 subjects with coronary artery disease, motion of the anterior, apical, and inferior walls agreed in every case with the right anterior oblique contrast ventriculogram, but in 12 of these, the three dimensional ejection fraction image showed abnormal septal motion, and in a further 3, abnormal lateral wall motion in addition. In the 12 subjects there was disease of the left anterior descending coronary artery, and in the further 3 there was left circumflex disease. ECG-gated blood pool emission tomography thus provides an accurate quantitative assessment of left ventricular wall motion in three dimensions, and has significant advantages over conventional planar techniques.

  2. Myocardial Blood Flow Quantification for Evaluation of Coronary Artery Disease by Positron Emission Tomography, Cardiac Magnetic Resonance Imaging, and Computed Tomography

    PubMed Central

    Waller, Alfonso H.; Blankstein, Ron; Kwong, Raymond Y.; Di Carli, Marcelo F.

    2014-01-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging and computed tomography, and its emerging clinical applications. PMID:24718671

  3. Bone single photon emission computed tomography with computed tomography disclosing chronic uterine perforation with intrauterine device migration into the anterior wall of the bladder: a case report

    PubMed Central

    2013-01-01

    Introduction Extraosseous uptake of 99mTc-hydroxymethylene diphosphonate is a common situation of variable clinical relevance. Case presentation A 52-year-old Caucasian woman presented to our department for breast cancer staging. A 99mTc-hydroxymethylene diphosphonate bone scan was performed and showed focal pelvic hyperfixation that disclosed intrauterine device migration into the anterior wall of the bladder on single photon emission computed tomography with computed tomography. Conclusion This observation confirms the major role of single photon emission computed tomography with computed tomography in achieving an exact diagnosis. PMID:23759143

  4. Adult granulosa cell tumor presenting with massive ascites, elevated CA-125 level, and low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography

    PubMed Central

    Tak, Ji Young; Park, Ji Y.; Lee, Seung Jeong; Lee, Yoon Hee; Hong, Dae Gy

    2015-01-01

    Adult granulosa cell tumors (AGCTs) presenting with massive ascites and elevated serum CA-125 levels have rarely been described in the literature. An ovarian mass, massive ascites, and elevated serum CA-125 levels in postmenopausal women generally suggest a malignant ovarian tumor, particularly advanced epithelial ovarian cancer. AGCT has low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography due to its low metabolic activity. In the present report, we describe a case of an AGCT with massive ascites, elevated serum CA-125 level, and low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography. PMID:26430671

  5. Effects of Respiration-Averaged Computed Tomography on Positron Emission Tomography/Computed Tomography Quantification and its Potential Impact on Gross Tumor Volume Delineation

    SciTech Connect

    Chi, Pai-Chun Melinda; Mawlawi, Osama; Luo Dershan; Liao Zhongxing; Macapinlac, Homer A.; Pan Tinsu

    2008-07-01

    Purpose: Patient respiratory motion can cause image artifacts in positron emission tomography (PET) from PET/computed tomography (CT) and change the quantification of PET for thoracic patients. In this study, respiration-averaged CT (ACT) was used to remove the artifacts, and the changes in standardized uptake value (SUV) and gross tumor volume (GTV) were quantified. Methods and Materials: We incorporated the ACT acquisition in a PET/CT session for 216 lung patients, generating two PET/CT data sets for each patient. The first data set (PET{sub HCT}/HCT) contained the clinical PET/CT in which PET was attenuation corrected with a helical CT (HCT). The second data set (PET{sub ACT}/ACT) contained the PET/CT in which PET was corrected with ACT. We quantified the differences between the two datasets in image alignment, maximum SUV (SUV{sub max}), and GTV contours. Results: Of the patients, 68% demonstrated respiratory artifacts in the PET{sub HCT}, and for all patients the artifact was removed or reduced in the corresponding PET{sub ACT}. The impact of respiration artifact was the worst for lesions less than 50 cm{sup 3} and located below the dome of the diaphragm. For lesions in this group, the mean SUV{sub max} difference, GTV volume change, shift in GTV centroid location, and concordance index were 21%, 154%, 2.4 mm, and 0.61, respectively. Conclusion: This study benchmarked the differences between the PET data with and without artifacts. It is important to pay attention to the potential existence of these artifacts during GTV contouring, as such artifacts may increase the uncertainties in the lesion volume and the centroid location.

  6. The Use and Misuse of Positron Emission Tomography in Lung Cancer Evaluation

    PubMed Central

    Chang, Ching-Fei; Rashtian, Afshin; Gould, Michael K.

    2011-01-01

    Synopsis Positron emission tomography (PET) has been studied for a variety of indications in patients with known or suspected non-small cell lung cancer (NSCLC). In this review, we discuss the potential benefits and limitations of PET for characterizing lung nodules, staging the mediastinum, identifying occult distant metastasis, determining prognosis and treatment response, guiding plans for radiation therapy, restaging during and after treatment, and selecting targets for tissue sampling. (Table 1) Evidence from randomized, controlled trials supports the use of PET for initial staging in NSCLC, while lower quality evidence from studies of diagnostic accuracy and modeling studies supports the use of PET for characterizing lung nodules. For most other indications in NSCLC, additional studies are required to clarify the role of PET and determine who is most likely to benefit. PMID:22054883

  7. Occupancy of serotonin and norepinephrine transporter by milnacipran in patients with major depressive disorder: a positron emission tomography study with [(11)C]DASB and (S,S)-[(18)F]FMeNER-D(2).

    PubMed

    Nogami, Tsuyoshi; Takano, Harumasa; Arakawa, Ryosuke; Ichimiya, Tetsuya; Fujiwara, Hironobu; Kimura, Yasuyuki; Kodaka, Fumitoshi; Sasaki, Takeshi; Takahata, Keisuke; Suzuki, Masayuki; Nagashima, Tomohisa; Mori, Takaaki; Shimada, Hitoshi; Fukuda, Hajime; Sekine, Mizuho; Tateno, Amane; Takahashi, Hidehiko; Ito, Hiroshi; Okubo, Yoshiro; Suhara, Tetsuya

    2013-06-01

    Antidepressants used for treatment of depression exert their efficacy by blocking reuptake at serotonin transporters (5-HTT) and/or norepinephrine transporters (NET). Recent studies suggest that serotonin and norepinephrine reuptake inhibitors that block both 5-HTT and NET have better tolerability than tricyclic antidepressants and may have higher efficacy compared to selective serotonin reuptake inhibitors. Previous positron emission tomography (PET) studies have reported >80% 5-HTT occupancy with clinical doses of antidepressants, but there has been no report of NET occupancy in patients treated with antidepressants. In the present study, we investigated both 5-HTT and NET occupancies by PET using radioligands [(11)C]DASB and (S,S)-[(18)F]FMeNER-D(2), in six patients, each with major depressive disorder (MDD), using various doses of milnacipran. Our data show that mean 5-HTT occupancy in the thalamus was 33.0% at 50 mg, 38.6% at 100 mg, 60.0% at 150 mg and 61.5% at 200 mg. Mean NET occupancy in the thalamus was 25.3% at 25 mg, 40.0% at 100 mg, 47.3% at 125 mg and 49.9% at 200 mg. Estimated ED(50) was 122.5 mg with the dose for 5-HTT and 149.9 mg for NET. Both 5-HTT and NET occupancies were observed in a dose-dependent manner. Both 5-HTT and NET occupancies were about 40% by milnacipran at 100 mg, the dose most commonly administered to MDD patients. PMID:23067569

  8. An atlas of Doppler emission-line tomography of cataclysmic variable stars

    NASA Technical Reports Server (NTRS)

    Kaitchuck, Ronald H.; Schlegel, Eric M.; Honeycutt, R. Kent; Horne, Keith; Marsh, T. R.; White, J. C., II; Mansperger, Cathy S.

    1994-01-01

    Doppler emission-line tomography is a technique similar to medical tomography. In this atlas the emission-line profiles of cataclysmic variable stars, seen at different orbital phases, are transformed into velocity space images. This transformation makes many of the complex line profile changes easier to interpret. The emission contributions of the disk and the s-wave are clearly separated in these images, and any emission from the stream and the secondary star can often be identified. In this atlas, Doppler tomograms of Hbeta, He I lambda 4471, and He II lambda 4686 emission lines of 18 cataclysmic variable stars are presented. The Doppler images provide insights into the individual systems and a better technique for measuring and radial velocity amplitude of the white dwarf.

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

    SciTech Connect

    Wu, J.C.; Hagman, J.; Buchsbaum, M.S.; Blinder, B.; Derrfler, M.; Tai, W.Y.; Hazlett, E.; Sicotte, N. )

    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.

  10. New techniques for positron emission tomography in the study of human neurological disorders: Progress report, 15 June 1992--31 October 1992

    SciTech Connect

    Not Available

    1992-10-01

    During the past six months, we have continued work on the fronts of kinetic modeling of radioligands for studying neurotransmitter/receptor systems, iterative reconstruction techniques, and methodology for PET cerebral blood flow activation studies. Initial human PET studies have been performed and analyzed with many different kinetic model formulations to determine the quantitative potential of the neuronwsmitter/receptor ligand, [{sup 11}C]N-methyl piperidyl benzilate (NMPB), a muscarinic cholinergic antagonist. In addition, initial human studies using [{sup 11}C]tetrabenazine (TBZ), a marker for monoantine nerve terminal density. Results of the NWB studies have indicated that this new agent yields better estimates of receptor density than previous muscarinic ligands developed at our facility, [{sup 11}C]-TRB and [{sup 11}C]scopolamine. TRB and scopolamine have previously been shown to be only partially successful ligands due to sub-optimal values of the individual rate constants, causing varying degrees of flow limitation. This is found to be much less of a problem for NMPB due to the 2.0--2.5 fold increase in ligand transport observed in the human studies ({approximately}60% first pass extraction). A 2-parameter 2-compartment simplification had previously been implemented for the benzodiazepine ligand, [C-11]FMZ, and a similar model appears to be suitable for TBZ based on the preliminary human data.

  11. New techniques for positron emission tomography in the study of human neurological disorders: Progress report, 15 June 1992--31 October 1992

    SciTech Connect

    Not Available

    1992-01-01

    During the past six months, we have continued work on the fronts of kinetic modeling of radioligands for studying neurotransmitter/receptor systems, iterative reconstruction techniques, and methodology for PET cerebral blood flow activation studies. Initial human PET studies have been performed and analyzed with many different kinetic model formulations to determine the quantitative potential of the neuronwsmitter/receptor ligand, ({sup 11}C)N-methyl piperidyl benzilate (NMPB), a muscarinic cholinergic antagonist. In addition, initial human studies using ({sup 11}C)tetrabenazine (TBZ), a marker for monoantine nerve terminal density. Results of the NWB studies have indicated that this new agent yields better estimates of receptor density than previous muscarinic ligands developed at our facility, ({sup 11}C)-TRB and ({sup 11}C)scopolamine. TRB and scopolamine have previously been shown to be only partially successful ligands due to sub-optimal values of the individual rate constants, causing varying degrees of flow limitation. This is found to be much less of a problem for NMPB due to the 2.0--2.5 fold increase in ligand transport observed in the human studies ({approximately}60% first pass extraction). A 2-parameter 2-compartment simplification had previously been implemented for the benzodiazepine ligand, (C-11)FMZ, and a similar model appears to be suitable for TBZ based on the preliminary human data.

  12. Characterization of brain mGluR5 binding in a pilot study of late-life major depressive disorder using positron emission tomography and [11C]ABP688

    PubMed Central

    DeLorenzo, C; Sovago, J; Gardus, J; Xu, J; Yang, J; Behrje, R; Kumar, J S D; Devanand, D P; Pelton, G H; Mathis, C A; Mason, N S; Gomez-Mancilla, B; Aizenstein, H; Mann, J J; Parsey, R V

    2015-01-01

    The metabotropic glutamate receptor subtype 5 (mGluR5) has been implicated in the pathophysiology of mood and anxiety disorders and is a potential treatment target in major depressive disorder (MDD). This study compared brain mGluR5 binding in elderly patients suffering from MDD with that in elderly healthy volunteers using positron emission tomography (PET) and [11C]ABP688. Twenty elderly (mean age: 63.0±6.3) subjects with MDD and twenty-two healthy volunteers in the same age range (mean age: 66.4±7.3) were examined with PET after a single bolus injection of [11C]ABP688, with many receiving arterial sampling. PET images were analyzed on a region of interest and a voxel level to compare mGluR5 binding in the brain between the two groups. Differences in [11C]ABP688 binding between patients with early- and late-onset depression were also assessed. In contrast to a previously published report in a younger cohort, no significant difference in [11C]ABP688 binding was observed between elderly subjects with MDD and healthy volunteers. [11C]ABP688 binding was also similar between subgroups with early- or late-onset depression. We believe this is the first study to examine mGluR5 expression in depression in the elderly. Although future work is required, results suggest potential differences in the pathophysiology of elderly depression versus depression earlier in life. PMID:26645628

  13. Lower Monoamine Oxidase-A Total Distribution Volume in Impulsive and Violent Male Offenders with Antisocial Personality Disorder and High Psychopathic Traits: An [11C] Harmine Positron Emission Tomography Study

    PubMed Central

    Kolla, Nathan J; Matthews, Brittany; Wilson, Alan A; Houle, Sylvain; Bagby, R Michael; Links, Paul; Simpson, Alexander I; Hussain, Amina; Meyer, Jeffrey H

    2016-01-01

    Antisocial personality disorder (ASPD) often presents with highly impulsive, violent behavior, and pathological changes in the orbitofrontal cortex (OFC) and ventral striatum (VS) are implicated. Several compelling reasons support a relationship between low monoamine oxidase-A (MAO-A), an enzyme that regulates neurotransmitters, and ASPD. These include MAO-A knockout models in rodents evidencing impulsive aggression and positron emission tomography (PET) studies of healthy subjects reporting associations between low brain MAO-A levels and greater impulsivity or aggression. However, a fundamental gap in the literature is that it is unknown whether brain MAO-A levels are low in more severe, clinical disorders of impulsivity, such as ASPD. To address this issue, we applied [11C] harmine PET to measure MAO-A total distribution volume (MAO-A VT), an index of MAO-A density, in 18 male ASPD participants and 18 age- and sex-matched controls. OFC and VS MAO-A VT were lower in ASPD compared with controls (multivariate analysis of variance (MANOVA): F2,33 = 6.8, P = 0.003; OFC and VS MAO-A VT each lower by 19%). Similar effects were observed in other brain regions: prefrontal cortex, anterior cingulate cortex, dorsal putamen, thalamus, hippocampus, and midbrain (MANOVA: F7,28 = 2.7, P = 0.029). In ASPD, VS MAO-A VT was consistently negatively correlated with self-report and behavioral measures of impulsivity (r = −0.50 to −0.52, all P-values<0.05). This study is the first to demonstrate lower brain MAO-A levels in ASPD. Our results support an important extension of preclinical models of impulsive aggression into a human disorder marked by pathological aggression and impulsivity. PMID:26081301

  14. Systematic Endobronchial Ultrasound-guided Mediastinal Staging Versus Positron Emission Tomography for Comprehensive Mediastinal Staging in NSCLC Before Radical Radiotherapy of Non-small Cell Lung Cancer: A Pilot Study.

    PubMed

    Steinfort, Daniel P; Siva, Shankar; Leong, Tracy L; Rose, Morgan; Herath, Dishan; Antippa, Phillip; Ball, David L; Irving, Louis B

    2016-02-01

    Despite known limitations of positron emission tomography (PET) for mediastinal staging of non-small cell lung cancer (NSCLC), radiation treatment fields are generally based on PET-identified disease extent. However, no studies have examined the accuracy of FDG-PET/CT on a per-node basis in patients being considered for curative-intent radiotherapy in NSCLC.In a prospective trial, patients with NSCLC being considered for definitive thoracic radiotherapy (± systemic chemotherapy) underwent minimally invasive systematic mediastinal evaluation with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) following noninvasive staging with integrated PET-CT.Thirty patients underwent EBUS-TBNA, with TBNA performed from a mean 2.5 lymph node (LN) stations per patient (median 3, range 1-5). Discordant findings between PET-CT and EBUS-TBNA were observed in 10 patients (33%, 95% CI 19%-51%). PET-occult LN metastases were demonstrated by EBUS in 4 patients, whereas a lesser extent of mediastinal involvement, compared with FDG-PET, was demonstrated by EBUS in 6 patients, including 2 patients downstaged from cN3 to pN2. LNs upstaged by EBUS were significantly smaller than nodes downstaged by EBUS, 7.5 mm (range 7-9) versus 12 mm (range 6-21), P = 0.005.A significant proportion of patients considered for definitive radiotherapy (+/-chemotherapy) undergoing systematic mediastinal evaluation with EBUS-TBNA in this study have an extent of mediastinal NSCLC involvement discordant with that indicated by PET-CT. Systematic EBUS-TBNA may aid in defining the extent of mediastinal involvement in NSCLC patients undergoing radiotherapy. Systematic EBUS-TBNA has the potential to contribute significantly to radiotherapy planning and delivery, by either identifying occult nodal metastases, or demonstrating FDG-avid LNs to be disease-free. PMID:26937894

  15. Lower Monoamine Oxidase-A Total Distribution Volume in Impulsive and Violent Male Offenders with Antisocial Personality Disorder and High Psychopathic Traits: An [(11)C] Harmine Positron Emission Tomography Study.

    PubMed

    Kolla, Nathan J; Matthews, Brittany; Wilson, Alan A; Houle, Sylvain; Bagby, R Michael; Links, Paul; Simpson, Alexander I; Hussain, Amina; Meyer, Jeffrey H

    2015-10-01

    Antisocial personality disorder (ASPD) often presents with highly impulsive, violent behavior, and pathological changes in the orbitofrontal cortex (OFC) and ventral striatum (VS) are implicated. Several compelling reasons support a relationship between low monoamine oxidase-A (MAO-A), an enzyme that regulates neurotransmitters, and ASPD. These include MAO-A knockout models in rodents evidencing impulsive aggression and positron emission tomography (PET) studies of healthy subjects reporting associations between low brain MAO-A levels and greater impulsivity or aggression. However, a fundamental gap in the literature is that it is unknown whether brain MAO-A levels are low in more severe, clinical disorders of impulsivity, such as ASPD. To address this issue, we applied [(11)C] harmine PET to measure MAO-A total distribution volume (MAO-A VT), an index of MAO-A density, in 18 male ASPD participants and 18 age- and sex-matched controls. OFC and VS MAO-A VT were lower in ASPD compared with controls (multivariate analysis of variance (MANOVA): F2,33=6.8, P=0.003; OFC and VS MAO-A VT each lower by 19%). Similar effects were observed in other brain regions: prefrontal cortex, anterior cingulate cortex, dorsal putamen, thalamus, hippocampus, and midbrain (MANOVA: F7,28=2.7, P=0.029). In ASPD, VS MAO-A VT was consistently negatively correlated with self-report and behavioral measures of impulsivity (r=-0.50 to -0.52, all P-values<0.05). This study is the first to demonstrate lower brain MAO-A levels in ASPD. Our results support an important extension of preclinical models of impulsive aggression into a human disorder marked by pathological aggression and impulsivity.

  16. Lower Monoamine Oxidase-A Total Distribution Volume in Impulsive and Violent Male Offenders with Antisocial Personality Disorder and High Psychopathic Traits: An [11C] Harmine Positron Emission Tomography Study

    PubMed Central

    Kolla, Nathan J; Matthews, Brittany; Wilson, Alan A; Houle, Sylvain; Michael Bagby, R; Links, Paul; Simpson, Alexander I; Hussain, Amina; Meyer, Jeffrey H

    2015-01-01

    Antisocial personality disorder (ASPD) often presents with highly impulsive, violent behavior, and pathological changes in the orbitofrontal cortex (OFC) and ventral striatum (VS) are implicated. Several compelling reasons support a relationship between low monoamine oxidase-A (MAO-A), an enzyme that regulates neurotransmitters, and ASPD. These include MAO-A knockout models in rodents evidencing impulsive aggression and positron emission tomography (PET) studies of healthy subjects reporting associations between low brain MAO-A levels and greater impulsivity or aggression. However, a fundamental gap in the literature is that it is unknown whether brain MAO-A levels are low in more severe, clinical disorders of impulsivity, such as ASPD. To address this issue, we applied [11C] harmine PET to measure MAO-A total distribution volume (MAO-A VT), an index of MAO-A density, in 18 male ASPD participants and 18 age- and sex-matched controls. OFC and VS MAO-A VT were lower in ASPD compared with controls (multivariate analysis of variance (MANOVA): F2,33=6.8, P=0.003; OFC and VS MAO-A VT each lower by 19%). Similar effects were observed in other brain regions: prefrontal cortex, anterior cingulate cortex, dorsal putamen, thalamus, hippocampus, and midbrain (MANOVA: F7,28=2.7, P=0.029). In ASPD, VS MAO-A VT was consistently negatively correlated with self-report and behavioral measures of impulsivity (r=−0.50 to −0.52, all P-values<0.05). This study is the first to demonstrate lower brain MAO-A levels in ASPD. Our results support an important extension of preclinical models of impulsive aggression into a human disorder marked by pathological aggression and impulsivity. PMID:26081301

  17. Maturational changes in cerebral function in infants determined by /sup 18/FDG positron emission tomography

    SciTech Connect

    Chugani, H.T.; Phelps, M.E.

    1986-02-21

    2-Deoxy-2(/sup 18/F)fluro-D-glucose positron emission tomography performed in human infants during development revealed progressive changes in local cerebral glucose utilization. In infants 5 weeks of age and younger, glucose utilization was highest in the sensorimotor cortex, thalamus, midbrain-brainstem, and cerebellar vermis. By 3 months, glucose metabolic activity had increased in the parietal, temporal, and occipital cortices and the basal ganglia, with subsequent increases in frontal and various association regions occurring by 8 months. These functional changes measured with positron emission tomography are in agreement with behavioral, neurophysiological, and anatomical alterations known to occur during infant development. 32 references, 2 figures, 1 table.

  18. New techniques for positron emission tomography in the study of human neurological disorders: Progress report, December 15, 1987-June 14, 1988

    SciTech Connect

    Kuhl, D.E.

    1988-02-01

    A brief progress report is presented describing the preparation and animal testing of /sup 11/C scopolamine and /sup 18/F fluoride. Additional studies entitled ''Automated Arterial Blood Sampling System for PET,'' Rapid Data Analysis Schemes for Functional Imaging in PET,'' and ''Tracer Kinetic Modeling in PET Measures of Cholinergic Receptors'' are described

  19. The role of positron emission tomography/computed tomography in radiation therapy planning for patients with lung cancer.

    PubMed

    Mac Manus, Michael P; Hicks, Rodney J

    2012-09-01

    Positron emission tomography (PET)/computed tomography (CT) has rapidly assumed a critical role in the management of patients with locoregionally advanced lung cancers who are candidates for definitive radiation therapy (RT). Definitive RT is given with curative intent, but can only be successful in patients without distant metastasis and if all gross tumor is contained within the treated volume. An increasing body of evidence supports the use of PET-based imaging for selection of patients for both surgery and definitive RT. Similarly, the use of PET/CT images for accurate target volume definition in lung cancer is a dynamic area of research. Most available evidence on PET staging of lung cancer relates to non-small cell lung cancer (NSCLC). In general clinical use, (18)F-fluorodeoxyglucose (FDG) is the primary radiopharmaceutical useful in NSCLC. Other tracers, including proliferation markers and hypoxia tracers, may have significant roles in future. Much of the FDG-PET literature describing the impact of PET on actual patient management has concerned candidates for surgical resection. In the few prospective studies where PET was used for staging and patient selection in NSCLC candidates for definitive RT, 25%-30% of patients were denied definitive RT, generally because PET detected unsuspected advanced locoregional or distant metastatic disease. PET/CT and CT findings are often discordant in NSCLC but studies with clinical-pathological correlation always show that PET-assisted staging is more accurate than conventional assessment. In all studies in which "PET-defined" and "non-PET-defined" RT target volumes were compared, there were major differences between PET and non-PET volumes. Therefore, in cases where PET-assisted and non-PET staging are different and biopsy confirmation is unavailable, it is rational to use the most accurate modality (namely PET/CT) to define the target volume. The use of PET/CT in patient selection and target volume definition is likely

  20. The use of fluorine-18 fluorodeoxyglucose positron emission tomography for imaging human motor neuronal activation in the brain

    PubMed Central

    PAHK, KISOO; PARK, KUN-WOO; PYUN, SUNG BOM; LEE, JAE SUNG; KIM, SUNGEUN; CHOE, JAE GOL

    2015-01-01

    The present study aimed to visualize human motor neuronal activation in the brain using fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), and to develop an FDG-PET procedure for imaging neuronal activation. A male volunteer underwent 20 min periods of rest and motor activation, whilst being assessed using FDG-PET on two consecutive days. The motor task, which involved repetitively grasping and releasing the right hand, was performed during the initial 5 min of the activation period. Subtraction of the rest period signal from the activation PET images was performed using the subtraction ictal single-photon emission computed tomography co-registered to magnetic resonance imaging method. The subtracted image detected activation of the contralateral (left) primary motor cortex, supplementary motor area, and ipsilateral (right) cerebellum. In the present study, FDG-PET detected significantly increased motor-associated activation of the brain in a subject performing a motor task. PMID:26668604

  1. Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings of Post Traumatic Lymphangioma in a Young Adult Male

    PubMed Central

    Kwon, Sang Don; Chun, Kyung Ah; Kong, Eun Jung; Cho, Ihn Ho

    2016-01-01

    The authors report the case of a 34-year-old male, who underwent a fluorine-18 fluoro deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan 7 years after trauma for the evaluation of multifocal masses in the right iliac and right inguinal areas. CT findings showed multifocal low density masses and 18F-FDG PET revealed slightly increased uptake (maximum standardized uptake value [SUVmax] 3.1). These findings did not exclude the possibility of a benign or malignant lesion. To achieve differential diagnosis, partial surgical excision was performed and a pathologic examination subsequently revealed lymphangioma. Here, the authors describe the 18F-FDG PET/CT findings of a rare case of lymphangioma resulting from trauma. PMID:27699163

  2. Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings of Post Traumatic Lymphangioma in a Young Adult Male

    PubMed Central

    Kwon, Sang Don; Chun, Kyung Ah; Kong, Eun Jung; Cho, Ihn Ho

    2016-01-01

    The authors report the case of a 34-year-old male, who underwent a fluorine-18 fluoro deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan 7 years after trauma for the evaluation of multifocal masses in the right iliac and right inguinal areas. CT findings showed multifocal low density masses and 18F-FDG PET revealed slightly increased uptake (maximum standardized uptake value [SUVmax] 3.1). These findings did not exclude the possibility of a benign or malignant lesion. To achieve differential diagnosis, partial surgical excision was performed and a pathologic examination subsequently revealed lymphangioma. Here, the authors describe the 18F-FDG PET/CT findings of a rare case of lymphangioma resulting from trauma.

  3. Bilateral Diffuse Fluorodeoxyglucose Uptake in Thyroid Gland Diagnosed by Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Win, Aung Zaw; Aparici, Carina Mari

    2014-01-01

    Our patient is a female who was first diagnosed with breast cancer at the age of 23. A follow-up fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) at age 44 revealed diffuse high FDG uptake in an enlarged thyroid gland. Fine-needle aspiration (FNA) of the thyroid mass revealed estrogen receptor/progesterone receptor negative, human epidermal growth factor receptor 2+ breast cancer. To the best of our knowledge, this is the first case to report breast cancer metastasis to the thyroid in a diffuse pattern on FDG-PET/CT. Bilateral diffuse uptake of FDG in thyroid is the most commonly associated with benign conditions. However, FNA biopsies need to be done to rule out metastatic disease in thyroid lesions with diffuse high FDG uptake, especially for patients with history of cancer. PMID:25191131

  4. Myelin imaging with C-11 labeled diphenylmethanol and positron emission tomography

    SciTech Connect

    Herscovitch, P.; Dischino, D.D.; Kilbourn, M.R.; Welch, M.J.; Raichle, M.E.

    1985-05-01

    The authors have recently studied several C-11-labeled radiopharmaceuticals for their suitability as myelin imaging agents with positron emission tomography (PET). C-11 diphenylmethanol (DPM) was selected on the basis of its in vivo metabolic stability and high extraction and lipophilicity. PET studies were performed in three normal subjects and in one patient with multiple sclerosis (MS). Myelin distribution was imaged following the bolus intravenous administration of 25-30 mCi of C-11 DPM. Sequential scans were obtained after radiotracer administration to measure the DPM distribution as a function of time. In addition, regional cerebral blood flow was measured after the bolus intravenous injection of 0-15 water. A tomographic slice through the centrum semiovale was used to obtain regional data for gray matter (GM) and white matter (WM).

  5. Positron emission tomography radioligands for in vivo imaging of Aβ plaques

    PubMed Central

    Mason, N. Scott; Mathis, Chester A.; Klunk, William E.

    2014-01-01

    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 therapies for Alzheimer’s disease. This review focuses on the development of these ligands, as well as the radiochemistry and current regulatory status of these PET radioligands. Particular attention is given to those ligands that have progressed to the later stages of drug development (phase II/III clinical trial studies) or approved New Drug Application status. PMID:24285314

  6. Diagnosis of Alzheimer-type dementia: a preliminary comparison of positron emission tomography and proton magnetic resonance

    SciTech Connect

    Friedland, R.P.; Budinger, T.F.; Brant-Zawadzki, M.; Jagust, W.J.

    1984-11-16

    The use of positron emission tomography with (18F)-2-fluoro-2-deoxy-D-glucose (FDG) to study glucose metabolism in dementia is described and compared with the use of magnetic resonance imaging. These studies suggest that physiological imaging with PET may be superior to MR as it is currently used in the diagnosis of dementia-like diseases. Pet is currently limited to a few centers; however, single photon emission CT can provide regional physiological data without the need for a local cyclotron. 15 references, 2 tables.

  7. 18F-fluorodeoxyglucose positron emission tomography imaging in brain tumours: the Western Australia positron emission tomography/cyclotron service experience.

    PubMed

    McCarthy, M; Yuan, J B; Campbell, A; Lenzo, N P; Butler-Henderson, K

    2008-12-01

    (18)F-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.

  8. Synthesis and positron emission tomography studies of C-11 labeled isotopomers and metabolites of GTS-21, a partial α7 nicotinic cholinergic agonist drug

    PubMed Central

    Kim, Sung Won; Ding, Yu-Shin; Alexoff, David; Patel, Vinal; Logan, Jean; Lin, Kuo-Shyan; Shea, Colleen; Muench, Lisa; Xu, Youwen; Carter, Pauline; King, Payton; Constanzo, Jasmine R.; Ciaccio, James A.; Fowler, Joanna S.

    2009-01-01

    Introduction GTS-21 ((3E)-3-[(2,4-dimethoxyphenyl)methylene]-3,4,5,6-tetrahydro-2,3′-bipyridine), a partial α7 nicotinic acetylcholine receptor agonist drug, has recently been shown to improve cognition in schizophrenia and Alzheimer’s disease. One of its two major demethylated metabolites, 4-OH-GTS-21, has been suggested to contribute to its therapeutic effects. Methods We labeled GTS-21 in two different positions with carbon-11 ([2-methoxy-11C]GTS-21 and [4-methoxy-11C]GTS-21) along with two corresponding demethylated metabolites ([2-methoxy-11C]4-OH-GTS-21 and [4-methoxy-11C]2-OH-GTS-21) for pharmacokinetic studies in baboons and mice with PET. Results Both [2-methoxy-11C]GTS-21 and [4-methoxy-11C]GTS-21 showed similar initial high rapid uptake in baboon brain, peaking from 1–3.5 min (0.027–0.038 %ID/cc) followed by rapid clearance (t1/2 <15 min), resulting in low brain retention by 30 min. However, after 30 min, [2-methoxy-11C]GTS-21 continued to clear while [4-methoxy-11C]GTS-21 plateaued, suggesting the entry of a labeled metabolite into the brain. Comparison of the pharmacokinetics of the two labeled metabolites confirmed expected higher brain uptake and retention of [4-methoxy-11C]2-OH-GTS-21 (the labeled metabolite of [4-methoxy-11C]GTS-21) relative to [2-methoxy-11C]4-OH-GTS-21 (the labeled metabolite of [2-methoxy-11C]GTS-21) which had negligible brain uptake. Ex vivo studies in mice showed that GTS-21 is the major chemical form in the mouse brain. Whole body dynamic PET imaging in baboon and mouse showed that the major route of excretion of C-11 is through the gallbladder. Conclusions The major findings are (1) extremely rapid uptake and clearance of [2-methoxy-11C]GTS-21 from the brain which may need to be considered in developing optimal dosing of GTS-21 for patients, and (2) significant brain uptake of 2-OH-GTS-21, suggesting that it might contribute to the therapeutic effects of GTS-21. This study illustrates the value of comparing

  9. Use of a tantalum-178 generator and a multiwire gamma camera to study the effect of the Mueller maneuver on left ventricular performance: comparison to hemodynamics and single photon emission computed tomography perfusion patterns.

    PubMed

    Gioia, G; Lin, B; Katz, R; DiMarino, A J; Ogilby, J D; Cassel, D; DePace, N L; Heo, J; Iskandrian, A S

    1995-11-01

    During the Mueller maneuver, there is a decrease in intrathoracic pressure and an increase in transmural left ventricular pressure. The changes in loading conditions cause transient left ventricular dysfunction. This study examined the effects of the Mueller maneuver on left ventricular performance using tantalum (Ta)-178 (half-life 9.3 min) and a multiwire gamma camera. First-pass radionuclide angiograms were obtained at baseline and during Mueller maneuver in 41 patients aged 58 +/- 10 years. In 34 patients, stress single photon emission computed tomography (SPECT) myocardial perfusion imaging with thallium-201 or sestamibi was also performed. Hemodynamic measurements during the Mueller maneuver (n = 10) showed a decrease in systemic pressure (139 +/- 25 mm Hg vs 123 +/- 24 mm Hg, p < 0.001) and pulmonary artery pressure (24 +/- 6 mm Hg vs 14 +/- 12 mm Hg, p = 0.01) and an increase in heart rate (67 +/- 10 bpm vs 75 +/- 14 beats/min, p = 0.001). Among the 34 patients who had perfusion imaging, the left ventricular ejection fraction remained unchanged or increased in 17 patients (group 1) (48% +/- 19% vs 49% +/- 21%, p not significant) and decreased (> or = 5%) in 17 patients (group 2) (55% +/- 13% vs 40% +/- 16%, p = 0.001). The stress SPECT images showed no or only fixed defects in 11 (65%) patients in group 1 and 3 (18%) patients in group 2 (p = 0.02), and reversible defects in 6 (35%) patients in group 1 and 14 (82%) patients in group 2 (p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

  10. LC-MS Supported Studies on the in Vitro Metabolism of both Enantiomers of Flubatine and the in Vivo Metabolism of (+)-[(18)F]Flubatine-A Positron Emission Tomography Radioligand for Imaging α4β2 Nicotinic Acetylcholine Receptors.

    PubMed

    Ludwig, Friedrich-Alexander; Smits, René; Fischer, Steffen; Donat, Cornelius K; Hoepping, Alexander; Brust, Peter; Steinbach, Jörg

    2016-01-01

    Both enantiomers of [(18)F]flubatine are promising radioligands for neuroimaging of α4β2 nicotinic acetylcholine receptors (nAChRs) by positron emission tomography (PET). To support clinical studies in patients with early Alzheimer's disease, a detailed examination of the metabolism in vitro and in vivo has been performed. (+)- and (-)-flubatine, respectively, were incubated with liver microsomes from mouse and human in the presence of NADPH (β-nicotinamide adenine dinucleotide 2'-phosphate reduced tetrasodium salt). Phase I in vitro metabolites were detected and their structures elucidated by LC-MS/MS (liquid chromatography-tandem mass spectrometry). Selected metabolite candidates were synthesized and investigated for structural confirmation. Besides a high level of in vitro stability, the microsomal incubations revealed some species differences as well as enantiomer discrimination with regard to the formation of monohydroxylated products, which was identified as the main metabolic pathway in this assay. Furthermore, after injection of 250 MBq (+)-[(18)F]flubatine (specific activity > 350 GBq/μmol) into mouse, samples were prepared from brain, liver, plasma, and urine after 30 min and investigated by radio-HPLC (high performance liquid chromatography with radioactivity detection). For structure elucidation of the radiometabolites of (+)-[(18)F]flubatine formed in vivo, identical chromatographic conditions were applied to LC-MS/MS and radio-HPLC to compare samples obtained in vitro and in vivo. By this correlation approach, we assigned three of four main in vivo radiometabolites to products that are exclusively C- or N-hydroxylated at the azabicyclic ring system of the parent molecule. PMID:27617996

  11. Synthesis of (R)-(-)- and (S)-(+)-4-fluorodeprenyl and (R)-(-)- and (S)-(+)-(N- sup 11 C-methyl)-4-fluorodeprenyl and positron emission tomography studies in baboon brain

    SciTech Connect

    Plenevaux, A.; Dewey, S.L.; Fowler, J.S.; Guillaume, M.; Wolf, A.P. )

    1990-07-01

    (R)-(-)- and (S)-(+)-alpha-methyl-beta-4-(fluorophenyl)-N-methyl-N- propynylethylamine (R)-(-)- and (S)-(+)-4-fluorodeprenyl were synthesized via the reaction of 4-fluorobenzaldehyde with nitroethane followed by reduction with lithium aluminum hydride to produce racemic 4-fluoroamphetamine, which was resolved by recrystallization with L- or D-N-acetylleucine to yield (R)-(-)-4-fluoroamphetamine or (S)-(+)-4-fluoroamphetamine in greater than 96% enantiomeric excesses and in yields of 42 and 39%, respectively. Alkylation with propargyl bromide gave (R)-(-)- or (S)-(+)-4-fluoronordeprenyl which was reductively methylated (Borch conditions) to produce (R)-(-)- or (S)-(+)-4-fluorodeprenyl. Alkylation of (R)-(-)- or (S)-(+)-4-fluoronordeprenyl with carbon-11 labeled methyl iodide gave (R)-(-)- or (S)-(+)-(N-11C-methyl)-4-fluorodeprenyl in a radiochemical yield of 30-40%. Comparative PET studies of the two labeled enantiomers in baboons showed a significantly lower retention of radioactivity in the striatum for the (S)-(+) enantiomer relative to the (R)-(-) enantiomer.

  12. Statistical parametric mapping in brain single photon computed emission tomography after carbon monoxide intoxication.

    PubMed

    Watanabe, N; Nohara, S; Matsuda, H; Sumiya, H; Noguchi, K; Shimizu, M; Tsuji, S; Kinuya, S; Shuke, N; Yokoyama, K; Seto, H

    2002-04-01

    The purpose of this retrospective study was to assess regional cerebral blood flow in patients after carbon monoxide intoxication by using brain single photon emission computed tomography and statistical parametric mapping. Eight patients with delayed neuropsychiatric sequelae and ten patients with no neuropsychiatric symptoms after carbon monoxide intoxication were studied with brain single photon emission tomography imaging with 99mTc-hexamethyl-propyleneamine oxime. Forty-four control subjects were also studied. We used the adjusted regional cerebral blood flow images in relative flow distribution (normalization of global cerebral blood flow for each subject to 50 ml x 100 g(-1) x min(-1) with proportional scaling) to compare these groups with statistical parametric mapping. Using this technique, significantly decreased regional cerebral blood flow was noted extensively in the bilateral frontal lobes as well as the bilateral insula and a part of the right temporal lobe in the patients with delayed neuropsychiatric sequelae as compared with normal volunteers (P< 0.005). In the patients with no neuropsychiatric symptoms, significantly decreased regional blood flow in the bilateral frontal lobes particularly on the left side was detected. There was a significantly decreased regional cerebral blood flow in the right frontal lobe and insula in the patients with delayed neuropsychiatric sequelae as compared to those with no neuropsychiatric sequelae. It is concluded that statistical parametric mapping is a useful technique for highlighting differences in regional cerebral blood flow in patients following carbon monoxide intoxication as compared with normal volunteers. The selectively reduced blood flow noted in this investigation supports the contention that the decrease following carbon monoxide intoxication may be prolonged and further worsen in the frontal lobe. In addition, the present study may help to clarify the characteristics of the pathophysiological

  13. Pretreatment Staging Positron Emission Tomography/Computed Tomography in Patients With Inflammatory Breast Cancer Influences Radiation Treatment Field Designs

    SciTech Connect

    Walker, Gary V.; Niikura, Naoki; Yang Wei; Rohren, Eric; Valero, Vicente; Woodward, Wendy A.; Alvarez, Ricardo H.; Lucci, Anthony; Ueno, Naoto T.; Buchholz, Thomas A.

    2012-08-01

    Purpose: Positron emission tomography/computed tomography (PET/CT) is increasingly being utilized for staging of inflammatory breast cancer (IBC). The purpose of this study was to define how pretreatment PET/CT studies affected postmastectomy radiation treatment (PMRT) planning decisions for IBC. Methods and Materials: We performed a retrospective analysis of 62 patients diagnosed with IBC between 2004 and 2009, who were treated with PMRT in our institution and who had a staging PET/CT within 3 months of diagnosis. Patients received a baseline physical examination, staging mammography, ultrasonographic examination of breast and draining lymphatics, and chest radiography; most patients also had a bone scan (55 patients), liver imaging (52 patients), breast MRI (46 patients), and chest CT (25 patients). We compared how PET/CT findings affected PMRT, assuming that standard PMRT would target the chest wall, level III axilla, supraclavicular fossa, and internal mammary chain (IMC). Any modification of target volumes, field borders, or dose prescriptions was considered a change. Results: PET/CT detected new areas of disease in 27 of the 62 patients (44%). The areas of additional disease included the breast (1 patient), ipsilateral axilla (1 patient), ipsilateral supraclavicular (4 patients), ipsilateral infraclavicular (1 patient), ipsilateral IMC (5 patients), ipsilateral subpectoral (3 patients), mediastinal (8 patients), other distant/contralateral lymph nodes (15 patients), or bone (6 patients). One patient was found to have a non-breast second primary tumor. The findings of the PET/CT led to changes in PMRT in 11 of 62 patients (17.7%). These changes included additional fields in 5 patients, adjustment of fields in 2 patients, and higher doses to the supraclavicular fossa (2 patients) and IMC (5 patients). Conclusions: For patients with newly diagnosed IBC, pretreatment PET/CT provides important information concerning involvement of locoregional lymph nodes

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

    SciTech Connect

    Chawluk, J.B.; Alavi, A.; Dann, R.; Hurtig, H.I.; Bais, S.; Kushner, M.J.; Zimmerman, R.A.; Reivich, M.

    1987-04-01

    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 (/sup 18/F)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.

  15. A head motion measurement system suitable for emission computed tomography

    SciTech Connect

    Goldstein, S.R.; Eidsath, A.; Daube-Witherspoon, M.E.; Green, M.V.

    1997-02-01

    Subject motion during brain imaging studies can adversely affect the images through loss of resolution and other artifacts related to movement. The authors have developed and tested a device to measure heat motion externally in real-time during emission computed tomographic (ECT) brain imaging studies, to be used eventually to correct ECT data for that motion. The system is based on optical triangulation of three miniature lights affixed to the patient`s head and viewed by two position-sensitive detectors. The computer-controlled device converts the three sets of lamp positions into rotational and translational coordinates every 0.7 seconds. When compared against a mechanical test fixture, the optical system was found to be linear and accurate with minimal crosstalk between the coordinates. In a study of two subjects, comparing the angular motions measured by the optical device and a commercially available electromagnetic motion detector, the two systems agreed well, with an root mean square (rms) difference of less than 0.6{degree} for all rotations.

  16. Model-based respiratory motion compensation for emission tomography image reconstruction.

    PubMed

    Reyes, M; Malandain, G; Koulibaly, P M; González-Ballester, M A; Darcourt, J

    2007-06-21

    In emission tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations, imprecise diagnosis, impairing of fusion with other modalities, etc. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested, which lead to improvements over the spatial activity distribution in lungs lesions, but which have the disadvantages of requiring additional instrumentation or the need of discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory motion compensation directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the maximum likelihood expectation maximization (MLEM) algorithm that includes a respiratory motion model, which takes into account the displacements and volume deformations produced by the respiratory motion during the data acquisition process. We present results from synthetic simulations incorporating real respiratory motion as well as from phantom and patient data.

  17. Brain perfusion single photon emission computed tomography in major psychiatric disorders: From basics to clinical practice

    PubMed Central

    Santra, Amburanjan; Kumar, Rakesh

    2014-01-01

    Brain single photon emission computed tomography (SPECT) is a well-established and reliable method to assess brain function through measurement of regional cerebral blood flow (rCBF). It can be used to define a patient's pathophysiological status when neurological or psychiatric symptoms cannot be explained by anatomical neuroimaging findings. Though there is ample evidence validating brain SPECT as a technique to track human behavior and correlating psychiatric disorders with dysfunction of specific brain regions, only few psychiatrists have adopted brain SPECT in routine clinical practice. It can be utilized to evaluate the involvement of brain regions in a particular patient, to individualize treatment on basis of SPECT findings, to monitor the treatment response and modify treatment, if necessary. In this article, we have reviewed the available studies in this regard from existing literature and tried to present the evidence for establishing the clinical role of brain SPECT in major psychiatric illnesses. PMID:25400359

  18. Optical imaging of reporter gene expression using a positron-emission-tomography probe

    NASA Astrophysics Data System (ADS)

    Liu, Hongguang; Ren, Gang; Liu, Shuanglong; Zhang, Xiaofen; Chen, Luxi; Han, Peizhen; Cheng, Zhen

    2010-11-01

    Reporter gene/reporter probe technology is one of the most important techniques in molecular imaging. Lately, many reporter gene/reporter probe systems have been coupled to different imaging modalities such as positron emission tomography (PET) and optical imaging (OI). It has been recently found that OI techniques could be used to monitor radioactive tracers in vitro and in living subjects. In this study, we further demonstrate that a reporter gene/nuclear reporter probe system [herpes simplex virus type-1 thymidine kinase (HSV1-tk) and 9-(4-18F-fluoro-3-[hydroxymethyl] butyl) guanine ([18F]FHBG)] could be successfully imaged by OI in vitro and in vivo. OI with radioactive reporter probes will facilitate and broaden the applications of reporter gene/reporter probe techniques in medical research.

  19. Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET)/MRI for Lung Cancer Staging.

    PubMed

    Ohno, Yoshiharu; Koyama, Hisanobu; Lee, Ho Yun; Yoshikawa, Takeshi; Sugimura, Kazuro

    2016-07-01

    Tumor, lymph node, and metastasis (TNM) classification of lung cancer is typically performed with the TNM staging system, as recommended by the Union Internationale Contre le Cancer (UICC), the American Joint Committee on Cancer (AJCC), and the International Association for the Study of Lung Cancer (IASLC). Radiologic examinations for TNM staging of lung cancer patients include computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography with 2-[fluorine-18] fluoro-2-deoxy-D-glucose (FDG-PET), and FDG-PET combined with CT (FDG-PET/CT) and are used for pretherapeutic assessments. Recent technical advances in MR systems, application of fast and parallel imaging and/or introduction of new MR techniques, and utilization of contrast media have markedly improved the diagnostic utility of MRI in this setting. In addition, FDG-PET can be combined or fused with MRI (PET/MRI) for clinical practice. This review article will focus on these recent advances in MRI as well as on PET/MRI for lung cancer staging, in addition to a discussion of their potential and limitations for routine clinical practice in comparison with other modalities such as CT, FDG-PET, and PET/CT.

  20. Imaging Prostate Cancer: An Update on Positron Emission Tomography and Magnetic Resonance Imaging

    PubMed Central

    Turkbey, Baris; Choyke, Peter; Capala, Jacek

    2012-01-01

    Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an essential role in the clinical management of patients. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. Developments in imaging technologies, specifically magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT), have improved the detection rate of prostate cancer. MRI has improved lesion detection and local staging. Furthermore, MRI allows functional assessment with techniques such as diffusion-weighted MRI, MR spectroscopy, and dynamic contrast-enhanced MRI. The most common PET radiotracer, 18F-fluorodeoxyglucose, is not very useful in prostate cancer. However, in recent years other PET tracers have improved the accuracy of PET/CT imaging of prostate cancer. Among these, choline (labeled with 18F or 11C), 11C-acetate, and 18F-fluoride have demonstrated promising results, and other new radiopharmaceuticals are currently under evaluation in preclinical and clinical studies. PMID:20425625

  1. Positron Emission Tomography of Brain β-Amyloid and Tau Levels in Adults With Down Syndrome

    PubMed Central

    Nelson, Linda D.; Siddarth, Prabha; Kepe, Vladimir; Scheibel, Kevin E.; Huang, S. C.; Barrio, Jorge R.; Small, Gary W.

    2012-01-01

    Objectives To determine the neuropathological load in the living brain of nondemented adults with Down syndrome using positron emission tomography with 2-(1-{6-[(2-fluorine 18–labeled fluoroethyl)methylamino]-2-napthyl}ethylidene) malononitrile ([18F]FDDNP) and to assess the influence of age and cognitive and behavioral functioning. For reference, [18F]FDDNP binding values and patterns were compared with those from patients with Alzheimer disease and cognitively intact control participants. Design Cross-sectional clinical study. Participants Volunteer sample of 19 persons with Down syndrome without dementia (mean age, 36.7 years), 10 patients with Alzheimer disease (mean age, 66.5 years), and 10 controls (mean age, 43.8 years). Main Outcome Measures Binding of [18F]FDDNP in brain regions of interest, including the parietal, medial temporal, lateral temporal, and frontal lobes and posterior cingulate gyrus, and the average of all regions (global binding). Results The [18F]FDDNP binding values were higher in all brain regions in the Down syndrome group than in controls. Compared with the Alzheimer disease group, the Down syndrome group had higher [18F]FDDNP binding values in the parietal and frontal regions, whereas binding levels in other regions were comparable. Within the Down syndrome group, age correlated with [18F]FDDNP binding values in all regions except the posterior cingulate, and several measures of behavioral dysfunction showed positive correlations with global, frontal, parietal, and posterior cingulate [18F]FDDNP binding. Conclusions Consistent with neuropathological findings from postmortem studies, [18F]FDDNP positron emission tomography shows high binding levels in Down syndrome comparable to Alzheimer disease and greater levels than in members of a control group. The positive associations between [18F]FDDNP binding levels and age as well as behavioral dysfunction in Down syndrome are consistent with the age-related progression of Alzheimer

  2. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines.

    PubMed

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission H(α) (656 nm) and H(β) (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design.

  3. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines

    NASA Astrophysics Data System (ADS)

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission Hα (656 nm) and Hβ (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design.

  4. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines.

    PubMed

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission H(α) (656 nm) and H(β) (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design. PMID:27036771

  5. Detection of scalene lymph node metastases from lung cancer. Positron emission tomography.

    PubMed

    Scott, W J; Gobar, L S; Hauser, L G; Sunderland, J J; Dewan, N A; Sugimoto, J T

    1995-04-01

    Preliminary data indicate that positron emission tomography (PET) following injection of fluorodeoxyglucose F18 (FDG) is sensitive and specific for detecting malignant cells in chest tumors and mediastinal lymph nodes. We report a case of non-small cell lung cancer metastatic to clinically normal scalene lymph nodes that was correctly staged by FDG-PET. PMID:7705136

  6. Positron Emission Tomography Methods with Potential for Increased Understanding of Mental Retardation and Developmental Disabilities

    ERIC Educational Resources Information Center

    Sundaram, Senthil K.; Chugani, Harry T.; Chugani, Diane C.

    2005-01-01

    Positron emission tomography (PET) is a technique that enables imaging of the distribution of radiolabeled tracers designed to track biochemical and molecular processes in the body after intravenous injection or inhalation. New strategies for the use of radiolabeled tracers hold potential for imaging gene expression in the brain during development…

  7. Attention Performance in Autism and Regional Brain Metabolic Rate Assessed by Positron Emission Tomography. Brief Report.

    ERIC Educational Resources Information Center

    Buchsbaum, M. S.; And Others

    1992-01-01

    This evaluation of seven high functioning adults with autism utilized positron emission tomography on a visual vigilance task. Although the subjects, as a group, did as well as normal controls on the task, there was a lack of normal hemispheric asymmetry in glucose metabolic rate. A heterogeneous etiology for autism is suggested to explain…

  8. 77 FR 8262 - Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... HUMAN SERVICES Food and Drug Administration Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug Administration (FDA) is announcing the availability of a draft...

  9. The Neural Correlates of Driving Performance Identified Using Positron Emission Tomography

    ERIC Educational Resources Information Center

    Horikawa, E.; Okamura, N.; Tashiro, M.; Sakurada, Y.; Maruyama, M.; Arai, H.; Yamaguchi, K.; Sasaki, H.; Yanai, K.; Itoh, M.

    2005-01-01

    Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [^1^5O]H"2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and…

  10. Positron Emission Tomography in Cochlear Implant and Auditory Brainstem Implant Recipients.

    ERIC Educational Resources Information Center

    Miyamoto, Richard T.; Wong, Donald

    2001-01-01

    Positron emission tomography imaging was used to evaluate the brain's response to auditory stimulation, including speech, in deaf adults (five with cochlear implants and one with an auditory brainstem implant). Functional speech processing was associated with activation in areas classically associated with speech processing. (Contains five…

  11. Evaluation of external beam hardening filters on image quality of computed tomography and single photon emission computed tomography/computed tomography.

    PubMed

    Rana, Nivedita; Rawat, Dinesh; Parmar, Madan; Dhawan, Devinder Kumar; Bhati, Ashok Kumar; Mittal, Bhagwant Rai

    2015-01-01

    This study was undertaken to evaluate the effect of external metal filters on the image quality of computed tomography (CT) and single photon emission computed tomography (SPECT)/CT images. Images of Jaszack phantom filled with water and containing iodine contrast filled syringes were acquired using CT (120 kV, 2.5 mA) component of SPECT/CT system, ensuring fixation of filter on X-ray collimator. Different thickness of filters of Al and Cu (1 mm, 2 mm, 3 mm, and 4 mm) and filter combinations Cu 1 mm, Cu 2 mm, Cu 3 mm each in combination with Al (1 mm, 2 mm, 3 mm, and 4 mm), respectively, were used. All image sets were visually analyzed for streak artifacts and contrast to noise ratio (CNR) was derived. Similar acquisition was done using Philips CT quality control (QC) phantom and CNR were calculated for its lexan, perspex, and teflon inserts. Attenuation corrected SPECT/CT images of Jaszack phantom filled with 444-555 MBq (12-15 mCi) of (99m)Tc were obtained by applying attenuation correction map generated by hardened X-ray beam for different filter combination, on SPECT data. Uniformity, root mean square (rms) and contrast were calculated in all image sets. Less streak artifacts at iodine water interface were observed in images acquired using external filters as compared to those without a filter. CNR for syringes, spheres, and inserts of Philips CT QC phantom was almost similar to Al 2 mm, Al 3 mm, and without the use of filters. CNR decreased with increasing copper thickness and other filter combinations. Uniformity and rms were lower, and value of contrast was higher for SPECT/CT images when CT was acquired with Al 2 mm and 3 mm filter than for images acquired without a filter. The study suggests that for Infinia Hawkeye 4, SPECT/CT system, Al 2 mm, and 3 mm are the optimum filters for improving image quality of SPECT/CT images of Jaszack or Philips CT QC phantom keeping other parameters of CT constant.

  12. Regional myocardial metabolism in patients with acute myocardial infarction assessed by positron emission tomography

    SciTech Connect

    Schwaiger, M.; Brunken, R.; Grover-McKay, M.; Krivokapich, J.; Child, J.; Tillisch, J.H.; Phelps, M.E.; Schelbert, H.R.

    1986-10-01

    Positron emission tomography has been shown to distinguish between reversible and irreversible ischemic tissue injury. Using this technique, 13 patients with acute myocardial infarction were studied within 72 hours of onset of symptoms to evaluate regional blood flow and glucose metabolism with nitrogen (N)-13 ammonia and fluorine (F)-18 deoxyglucose, respectively. Serial noninvasive assessment of wall motion was performed to determine the prognostic value of metabolic indexes for functional tissue recovery. Segmental blood flow and glucose utilization were evaluated using a circumferential profile technique and compared with previously established semiquantitative criteria. Relative N-13 ammonia uptake was depressed in 32 left ventricular segments. Sixteen segments demonstrated a concordant decrease in flow and glucose metabolism. Regional function did not change over time in these segments. In contrast, 16 other segments with reduced blood flow revealed maintained F-18 deoxyglucose uptake consistent with remaining viable tissue. The average wall motion score improved significantly in these segments (p less than 0.01), yet the degree of recovery varied considerably among patients. Coronary anatomy was defined in 9 of 13 patients: patent infarct vessels supplied 8 of 10 segments with F-18 deoxyglucose uptake, while 10 of 13 segments in the territory of an occluded vessel showed concordant decreases in flow and metabolism (p less than 0.01). Thus, positron emission tomography reveals a high incidence of residual tissue viability in ventricular segments with reduced flow and impaired function during the subacute phase of myocardial infarction. Absence of residual tissue metabolism is associated with irreversible injury, while preservation of metabolic activity identifies segments with a variable outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Repeated Positron Emission Tomography-Computed Tomography and Perfusion-Computed Tomography Imaging in Rectal Cancer: Fluorodeoxyglucose Uptake Corresponds With Tumor Perfusion

    SciTech Connect

    Janssen, Marco H.M.; Aerts, Hugo J.W.L.; Buijsen, Jeroen; Lambin, Philippe; Lammering, Guido; Oellers, Michel C.

    2012-02-01

    Purpose: The purpose of this study was to analyze both the intratumoral fluorodeoxyglucose (FDG) uptake and perfusion within rectal tumors before and after hypofractionated radiotherapy. Methods and Materials: Rectal cancer patients, referred for preoperative hypofractionated radiotherapy (RT), underwent FDG-positron emission tomography (PET)-computed tomography (CT) and perfusion-CT (pCT) imaging before the start of hypofractionated RT and at the day of the last RT fraction. The pCT-images were analyzed using the extended Kety model, quantifying tumor perfusion with the pharmacokinetic parameters K{sup trans}, v{sub e}, and v{sub p}. The mean and maximum FDG uptake based on the standardized uptake value (SUV) and transfer constant (K{sup trans}) within the tumor were correlated. Also, the tumor was subdivided into eight subregions and for each subregion the mean and maximum SUVs and K{sup trans} values were assessed and correlated. Furthermore, the mean FDG uptake in voxels presenting with the lowest 25% of perfusion was compared with the FDG uptake in the voxels with the 25% highest perfusion. Results: The mean and maximum K{sup trans} values were positively correlated with the corresponding SUVs ({rho} = 0.596, p = 0.001 and {rho} = 0.779, p < 0.001). Also, positive correlations were found for K{sup trans} values and SUVs within the subregions (mean, {rho} = 0.413, p < 0.001; and max, {rho} = 0.540, p < 0.001). The mean FDG uptake in the 25% highest-perfused tumor regions was significantly higher compared with the 25% lowest-perfused regions (10.6% {+-} 5.1%, p = 0.017). During hypofractionated radiotherapy, stable mean (p = 0.379) and maximum (p = 0.280) FDG uptake levels were found, whereas the mean (p = 0.040) and maximum (p = 0.003) K{sup trans} values were found to significantly increase. Conclusion: Highly perfused rectal tumors presented with higher FDG-uptake levels compared with relatively low perfused tumors. Also, intratumor regions with a high FDG

  14. Field studies in geophysical diffraction tomography

    SciTech Connect

    Witten, A.J.; Stevens, S.S.; King, W.C.; Ursic, J.R.

    1992-07-01

    Geophysical diffraction tomography (GDT) is a quantitative, high- resolution technique for subsurface imaging. This method has been used in a number of shallow applications to image buried waste, trenches, soil strata, tunnels, synthetic magma chambers, and the buried skeletal remains of seismosaurus, the longest dinosaur ever discovered. The theory associated with the GDT inversion and implementing software have been developed for acoustic and scalar electromagnetic waves for bistatic and monostatic measurements in cross-borehole, offset vertical seismic profiling and reflection geometries. This paper presents an overview of some signal processing algorithms, a description of the instrumentation used in field studies, and selected imaging results.

  15. Field studies in geophysical diffraction tomography

    SciTech Connect

    Witten, A.J.; Stevens, S.S. ); King, W.C. . Dept. of Geography and Environmental Engineering); Ursic, J.R. . Region V)

    1992-01-01

    Geophysical diffraction tomography (GDT) is a quantitative, high- resolution technique for subsurface imaging. This method has been used in a number of shallow applications to image buried waste, trenches, soil strata, tunnels, synthetic magma chambers, and the buried skeletal remains of seismosaurus, the longest dinosaur ever discovered. The theory associated with the GDT inversion and implementing software have been developed for acoustic and scalar electromagnetic waves for bistatic and monostatic measurements in cross-borehole, offset vertical seismic profiling and reflection geometries. This paper presents an overview of some signal processing algorithms, a description of the instrumentation used in field studies, and selected imaging results.

  16. A Nonparametric Bayesian Approach For Emission Tomography Reconstruction

    NASA Astrophysics Data System (ADS)

    Barat, Éric; Dautremer, Thomas

    2007-11-01

    We introduce a PET reconstruction algorithm following a nonparametric Bayesian (NPB) approach. In contrast with Expectation Maximization (EM), the proposed technique does not rely on any space discretization. Namely, the activity distribution—normalized emission intensity of the spatial poisson process—is considered as a spatial probability density and observations are the projections of random emissions whose distribution has to be estimated. This approach is nonparametric in the sense that the quantity of interest belongs to the set of probability measures on Rk (for reconstruction in k-dimensions) and it is Bayesian in the sense that we define a prior directly on this spatial measure. In this context, we propose to model the nonparametric probability density as an infinite mixture of multivariate normal distributions. As a prior for this mixture we consider a Dirichlet Process Mixture (DPM) with a Normal-Inverse Wishart (NIW) model as base distribution of the Dirichlet Process. As in EM-family reconstruction, we use a data augmentation scheme where the set of hidden variables are the emission locations for each observed line of response in the continuous object space. Thanks to the data augmentation, we propose a Markov Chain Monte Carlo (MCMC) algorithm (Gibbs sampler) which is able to generate draws from the posterior distribution of the spatial intensity. A difference with EM is that one step of the Gibbs sampler corresponds to the generation of emission locations while only the expected number of emissions per pixel/voxel is used in EM. Another key difference is that the estimated spatial intensity is a continuous function such that there is no need to compute a projection matrix. Finally, draws from the intensity posterior distribution allow the estimation of posterior functionnals like the variance or confidence intervals. Results are presented for simulated data based on a 2D brain phantom and compared to Bayesian MAP-EM.

  17. Clinical evaluation of a high-resolution (2. 6-mm) positron emission tomography

    SciTech Connect

    Valk, P.E.; Jagust, W.J.; Derenzo, S.E.; Huesman, R.H.; Geyer, A.B.; Budinger, T.F. )

    1990-09-01

    The intrinsic resolution of the Donner 600-crystal positron emission tomograph (PET 600) is 2.6 mm full width at half maximum (FWHM) in-plane and 6 mm FWHM axially. More than 100 patients with glioma, radiation necrosis, Alzheimer disease, or epilepsy have been studied with this system. Approximately 1 million events are acquired in 15 minutes, starting 1 hour after injection of 10 mCi (370 MBq) of fluorine-18-fluorodeoxyglucose. Normal structures as small as the superior colliculi and the external capsule have been resolved. Improved separation of the cortical ribbon from adjacent white matter has allowed more accurate determination of cortical metabolic rate. In two of 15 patients undergoing evaluation for recurrent glioma, the PET 600 images showed tumor uptake that was not apparent on a lower-resolution study. A high-activity orbiting transmission source with electronic collimation allows accurate, short-duration transmission measurements to be made after radiopharmaceutical administration. The anatomic detail seen on the transmission images can be used for reproducible patient positioning with an accuracy of 1-2 mm perpendicular to the image plane. These findings demonstrate the practicality and clinical effectiveness of high-resolution positron emission tomography.

  18. Treatment modification of yttrium-90 radioembolization based on quantitative positron emission tomography/CT imaging.

    PubMed

    Chang, Ted T; Bourgeois, Austin C; Balius, Anastasia M; Pasciak, Alexander S

    2013-03-01

    Treatment activity for yttrium-90 ((90)Y) radioembolization when calculated by using the manufacturer-recommended technique is only partially patient-specific and may result in a subtumoricidal dose in some patients. The authors describe the use of quantitative (90)Y positron emission tomography/computed tomography as a tool to provide patient-specific optimization of treatment activity and evaluate this new method in a patient who previously received traditional (90)Y radioembolization. The modified treatment resulted in a 40-Gy increase in absorbed dose to tumor and complete resolution of disease in the treated area within 3 months.

  19. Multilayer mirror based line emission tomography for spherical Tokamaks

    SciTech Connect

    Stutman, D.; Hwang, Y.S.; Menard, J.; Choe, W.; Ono, M.; Finkenthal, M.; May, M.J.; Regan, S.P.; Soukhanovskii, V.; Moos, H.W.

    1997-01-01

    Due to their highly shaped plasma and possible poloidal asymmetry in impurity concentration, spherical Tokamaks will require tomographic reconstruction of local emissivities to assess impurity content and transport. To collect in an effective manner the data required for such reconstruction, we develop arrays of high throughput {open_quotes}mini-monochromators{close_quotes} using extreme ultraviolet multilayer mirrors as dispersive elements and filtered surface barrier diodes as detectors. We discuss monochromator optimization and show that by working at near normal incidence throughput and spectral resolution are simultaneously maximized. A system proposed for tomographic reconstruction of CV and CVI resonance emission at 33.7 and 40.5 {Angstrom} respectively, achieves 0.9 {Angstrom} spectral resolution, 2 cm spatial resolution, and 0.2 ms temporal resolution, together with good sensitivity and background rejection. Preliminary results obtained from CDX-U low aspect ratio tokamak are also presented. {copyright} {ital 1997 American Institute of Physics.}

  20. Evaluation of Technetium-99m glucoheptonate single photon emission computed tomography for brain tumor grading

    PubMed Central

    Alam, Syed Shafiq; Junaid, Syed; Ahmed, Syed Mushtaq

    2016-01-01

    Background: This study is designed to appraise the diagnostic value of technetium-99m glucoheptonate (Tc-99m GHA) single photon emission computed tomography (SPECT) in brain tumor grading. Subjects and Methods: The study was performed on 30 patients referred from the Department of Neurosurgery, who were from both urban and rural areas. Data were collected through interview, history taking, and clinical examination followed by recording the desired parameters and finally imaging. The study subjects were divided into five groups: Controls (n = 4), low-grade tumors (n = 8), high-grade tumors (n = 8), metastases (n = 5), and nonneoplastic lesions (n = 5). This division was based on the World Health Organization (WHO) classification postclinico-histological diagnosis. Each of the subjects underwent contrast-enhanced computed tomography/contrast-enhanced magnetic resonance and Tc-99m GHA SPECT preoperatively. All were followed up postoperatively, and histopathological reports were regarded as the gold standard for tumor grading wherever available. Results: It was found that high-grade tumors (Grades III/IV and IV/IV according to the WHO classification) showed significantly higher tumor to normal (T/N) ratios as well as Tmax/N ratios when compared with low-grade tumors (Grades I/IV and II/IV), metastases or nonneoplastic lesions. Conclusions: In summary, the results of this study suggest that in situations where a preoperative grading of tumor is required Tc-99m GHA can be used in tumor grading and its use should be encouraged. Semi-quantitative analysis using both T/N as well as Tmax/N can be used in differentiating high-grade tumors from low-grade ones. PMID:27057217

  1. Occupational Exposure to Veterinary Workers from the Positron Emission Tomography Imaging Agent 64Cu-ATSM.

    PubMed

    Hetrick, Lucas D; Kraft, Susan L; Johnson, Thomas E

    2015-11-01

    Cu-ATSM is an emerging radiopharmaceutical for diagnostic use in positron emission tomography (PET), but to date there are no studies that assess the potential occupational doses to workers in either human or veterinary medicine. This study was aimed at determining the external radiation dose to veterinary workers from clinical PET/CT (PET combined with computed tomography) procedures using Cu-ATSM. To determine the dose to the workers, each worker was assigned two Electronic Personal Dosimeters (EPDs) to be worn on the chest and waist during the entirety of each procedure. The workers monitored during this study included a radiobiologist, a nuclear medicine technologist, an anesthesiologist, and a veterinary surgeon. Seven canine patients were imaged with an average mass of 33.7 kg (a range of 20.0-55.1 kg) with an average injected activity of 5 MBq kg. The dose range for the radiobiologist was 2-17 μSv (mean of 7.1 μSv), for the nuclear medicine technologist 0-14 μSv (mean of 5.6 μSv), for the anesthesiologist 0-12 μSv (mean of 4.0 μSv), and for the surgeon 0-10 μSv (mean of 3.6 μSv). In a comparison between the results of this study and published literature on occupational exposures from veterinary FDG PET/CT procedures, Cu-ATSM veterinary PET/CT procedures, on a per patient bias, exposed workers to less radiation. PMID:26425985

  2. Determination of the spatial characteristics of an RF electrodeless discharge by the method of emission tomography

    SciTech Connect

    Denisova, N. V.; Revalde, G.; Skudra, A.

    2006-11-15

    The spatial distribution of the density of mercury atoms in the 7{sup 3}S state in a spherical RF electrode-less gas-discharge lamp is reconstructed by the method of emission tomography. The local values of the corresponding emission coefficients, which are proportional to the density of mercury atoms in the 7{sup 3}S state, are determined from integral (over the plasma volume) measurements of the lamp radiation at a wavelength of 546.1 nm with the help of an algorithm based on the maximum entropy method. The results obtained show that, for all of the operating modes under study, the profile of the density of mercury atoms in the 7{sup 3}S state has a minimum in the center of the lamp and a maximum near its wall. At a generator current of 100 mA and cold-spot temperature of 41 deg. C, the density of mercury atoms in the 7{sup 3}S state is observed to drop substantially both in the center of the lamp and near its wall, the density in the center being reduced to almost zero. An explanation of this phenomenon is proposed.

  3. Imaging of Tumor Metabolism Using Positron Emission Tomography (PET).

    PubMed

    Apostolova, Ivayla; Wedel, Florian; Brenner, Winfried

    2016-01-01

    Molecular imaging employing PET/CT enables in vivo visualization, characterization, and measurement of biologic processes in tumors at a molecular and cellular level. Using specific metabolic tracers, information about the integrated function of multiple transporters and enzymes involved in tumor metabolic pathways can be depicted, and the tracers can be directly applied as biomarkers of tumor biology. In this review, we discuss the role of F-18-fluorodeoxyglucose (FDG) as an in vivo glycolytic marker which reflects alterations of glucose metabolism in cancer cells. This functional molecular imaging technique offers a complementary approach to anatomic imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) and has found widespread application as a diagnostic modality in oncology to monitor tumor biology, optimize the therapeutic management, and guide patient care. Moreover, emerging methods for PET imaging of further biologic processes relevant to cancer are reviewed, with a focus on tumor hypoxia and aberrant tumor perfusion. Hypoxic tumors are associated with poor disease control and increased resistance to cytotoxic and radiation treatment. In vivo imaging of hypoxia, perfusion, and mismatch of metabolism and perfusion has the potential to identify specific features of tumor microenvironment associated with poor treatment outcome and, thus, contribute to personalized treatment approaches. PMID:27557539

  4. Digital contrast enhancement of 18Fluorine-fluorodeoxyglucose positron emission tomography images in hepatocellular carcinoma

    PubMed Central

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Agarwal, Krishan Kant; Sharma, Punit; Bal, Chandrasekhar; Kumar, Rakesh

    2016-01-01

    Purpose: The role of 18fluorodeoxyglucose positron emission tomography (PET) is limited for detection of primary hepatocellular carcinoma (HCC) due to low contrast to the tumor, and normal hepatocytes (background). The aim of the present study was to improve the contrast between the tumor and background by standardizing the input parameters of a digital contrast enhancement technique. Materials and Methods: A transverse slice of PET image was adjusted for the best possible contrast, and saved in JPEG 2000 format. We processed this image with a contrast enhancement technique using 847 possible combinations of input parameters (threshold “m” and slope “e”). The input parameters which resulted in an image having a high value of 2nd order entropy, and edge content, and low value of absolute mean brightness error, and saturation evaluation metrics, were considered as standardized input parameters. The same process was repeated for total nine PET-computed tomography studies, thus analyzing 7623 images. Results: The selected digital contrast enhancement technique increased the contrast between the HCC tumor and background. In seven out of nine images, the standardized input parameters “m” had values between 150 and 160, and for other two images values were 138 and 175, respectively. The value of slope “e” was 4 in 4 images, 3 in 3 images and 1 in 2 images. It was found that it is important to optimize the input parameters for the best possible contrast for each image; a particular value was not sufficient for all the HCC images. Conclusion: The use of above digital contrast enhancement technique improves the tumor to background ratio in PET images of HCC and appears to be useful. Further clinical validation of this finding is warranted. PMID:26917889

  5. Positron emission tomography as a diagnostic tool in infection: present role and future possibilities.

    PubMed

    Basu, Sandip; Chryssikos, Timothy; Moghadam-Kia, Siamak; Zhuang, Hongming; Torigian, Drew A; Alavi, Abass

    2009-01-01

    The past decade has witnessed the emergence of yet another promising application of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in the detection and management of patients with infection and inflammatory disorders. This phenomenon is quite evident when the peer-reviewed scientific literature is searched for on this topic. Among these scientific communications, the 6 conditions in which FDG-PET has demonstrated its greatest utility include (1) chronic osteomyelitis, (2) complicated lower-limb prostheses, (3) complicated diabetic foot, (4) fever of unknown origin, (5) acquired immunodeficiency syndrome (ie, AIDS), and (6) vascular graft infection and fistula. On the basis of published literature, orthopedic infections, particularly those related to implanted prostheses and osteomyelitis (including that occurring in the setting of a complicated diabetic foot), can be detected successfully by the use of FDG-PET and, therefore, this modality has great promise for becoming the study of choice in these complex settings. Increasingly, this technique is being used to detect infection in soft tissues, including those representing the sources of fever of unknown origin. The ability of FDG-PET to diagnose vascular graft infection and fistula, even when the anatomical imaging modalities are inconclusive, is of considerable interest to practitioners of vascular surgery. Combined PET/computed tomography (CT) imaging has the potential to determine the sites of infection or inflammation with high precision. The data on the role of PET/CT imaging in the assessment of infection and inflammation is sparse, but this combined modality approach may prove to be the study of choice in foreseeable future for precise localization of involved sites. However, the role of PET/CT may be limited in the presence of metallic artifacts (such as those caused by prostheses) adjacent to the sites of infection. PMID:19038599

  6. The Promise and Pitfalls of Positron Emission Tomography and Single-Photon Emission Computed Tomography Molecular Imaging–Guided Radiation Therapy

    PubMed Central

    Wahl, Richard L.; Herman, Joseph M.; Ford, Eric

    2015-01-01

    External beam radiation therapy procedures have, until recently, been planned almost exclusively using anatomic imaging methods. Molecular imaging using hybrid positron emission tomography (PET)/computed tomography scanning or single-photon emission computed tomography (SPECT) imaging has provided new insights into the precise location of tumors (staging) and the extent and character of the biologically active tumor volume (BTV) and has provided differential response information during and after therapy. In addition to the commonly used radiotracer 18F-fluoro- 2-deoxyD-glucose (FDG), additional radiopharmaceuticals are being explored to image major physiological processes as well as tumor biological properties, such as hypoxia, proliferation, amino acid accumulation, apoptosis, and receptor expression, providing the potential to target or boost the radiation dose to a biologically relevant region within a tumor, such as the most hypoxic or most proliferative area. Imaging using SPECT agents has furthered the possibility of limiting dose to functional normal tissues. PET can also portray the distribution of particle therapy by displaying activated species in situ. With both PET and SPECT imaging, fundamental physical issues of limited spatial resolution relative to the biological process, partial volume effects for quantification of small volumes, image misregistration, motion, and edge delineation must be carefully considered and can differ by agent or the method applied. Molecular imaging–guided radiation therapy (MIGRT) is a rapidly evolving and promising area of investigation and clinical translation. As MIGRT evolves, evidence must continue to be gathered to support improved clinical outcomes using MIGRT versus purely anatomic approaches. PMID:21356477

  7. Radiolabeling, whole-body single photon emission computed tomography/computed tomography imaging, and pharmacokinetics of carbon nanohorns in mice

    PubMed Central

    Zhang, Minfang; Jasim, Dhifaf A; Ménard-Moyon, Cécilia; Nunes, Antonio; Iijima, Sumio; Bianco, Alberto; Yudasaka, Masako; Kostarelos, Kostas

    2016-01-01

    In this work, we report that the biodistribution and excretion of carbon nanohorns (CNHs) in mice are dependent on their size and functionalization. Small-sized CNHs (30–50 nm; S-CNHs) and large-sized CNHs (80–100 nm; L-CNHs) were chemically functionalized and radiolabeled with [111In]-diethylenetriaminepentaacetic acid and intravenously injected into mice. Their tissue distribution profiles at different time points were determined by single photon emission computed tomography/computed tomography. The results showed that the S-CNHs circulated longer in blood, while the L-CNHs accumulated faster in major organs like the liver and spleen. Small amounts of S-CNHs- and L-CNHs were excreted in urine within the first few hours postinjection, followed by excretion of smaller quantities within the next 48 hours in both urine and feces. The kinetics of excretion for S-CNHs were more rapid than for L-CNHs. Both S-CNH and L-CNH material accumulated mainly in the liver and spleen; however, S-CNH accumulation in the spleen was more prominent than in the liver. PMID:27524892

  8. Application of positron emission tomography/computed tomography in radiation treatment planning for head and neck cancers

    PubMed Central

    Awan, Musaddiq J; Siddiqui, Farzan; Schwartz, David; Yuan, Jiankui; Machtay, Mitchell; Yao, Min

    2015-01-01

    18-fluorodeoxygluocose positron emission tomography/computed tomography (18FDG-PET/CT) provides significant information in multiple settings in the management of head and neck cancers (HNC). This article seeks to define the additional benefit of PET/CT as related to radiation treatment planning for squamous cell carcinomas (SCCs) of the head and neck through a review of relevant literature. By helping further define both primary and nodal volumes, radiation treatment planning can be improved using PET/CT. Special attention is paid to the independent benefit of PET/CT in targeting mucosal primaries as well as in detecting nodal metastases. The utility of PET/CT is also explored for treatment planning in the setting of SCC of unknown primary as PET/CT may help define a mucosal target volume by guiding biopsies for examination under anesthesia thus changing the treatment paradigm and limiting the extent of therapy. Implications of the use of PET/CT for proper target delineation in patients with artifact from dental procedures are discussed and the impact of dental artifact on CT-based PET attenuation correction is assessed. Finally, comment is made upon the role of PET/CT in the high-risk post-operative setting, particularly in the context of radiation dose escalation. Real case examples are used in these settings to elucidate the practical benefits of PET/CT as related to radiation treatment planning in HNCs. PMID:26644824

  9. 2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography/computed tomography imaging in paediatric oncology

    PubMed Central

    Freebody, John; Wegner, Eva A; Rossleigh, Monica A

    2014-01-01

    Positron emission tomography (PET) is a minimally invasive technique which has been well validated for the diagnosis, staging, monitoring of response to therapy, and disease surveillance of adult oncology patients. Traditionally the value of PET and PET/computed tomography (CT) hybrid imaging has been less clearly defined for paediatric oncology. However recent evidence has emerged regarding the diagnostic utility of these modalities, and they are becoming increasingly important tools in the evaluation and monitoring of children with known or suspected malignant disease. Important indications for 2-deoxy-2-(18F)fluoro-D-glucose (FDG) PET in paediatric oncology include lymphoma, brain tumours, sarcoma, neuroblastoma, Langerhans cell histiocytosis, urogenital tumours and neurofibromatosis type I. This article aims to review current evidence for the use of FDG PET and PET/CT in these indications. Attention will also be given to technical and logistical issues, the description of common imaging pitfalls, and dosimetric concerns as they relate to paediatric oncology. PMID:25349660

  10. Thoracic [18F]fluorodeoxyglucose uptake measured by positron emission tomography/computed tomography in pulmonary hypertension.

    PubMed

    Frille, Armin; Steinhoff, Karen Geva; Hesse, Swen; Grachtrup, Sabine; Wald, Alexandra; Wirtz, Hubert; Sabri, Osama; Seyfarth, Hans-Juergen

    2016-06-01

    Positron emission tomography (PET) visualizes increased cellular [F]fluorodeoxyglucose ([F]FDG) uptake. Pulmonary hypertension (PH) is conceived of a proliferative disease of the lung vessels. Increased glucose uptake can be quantified as pulmonary [F]FDG uptake via PET imaging. Because the angioproliferative mechanisms in PH are still in need of further description, the aim of the present study was to investigate whether [F]FDG PET/CT imaging can elucidate these pathophysiologic mechanisms in different etiologies of PH.Patients (n = 109) with end-stage pulmonary disease being evaluated for lung transplant were included in this observational study. Mean standardized uptake value (SUVmean) of predefined regions of interest in lung parenchyma (LP), left (LV), and right ventricle (RV) of the heart, and SUVmax in pulmonary artery (PA) were determined and normalized to liver uptake. These SUV ratios (SUVRs) were compared with results from right heart catheterization (mean pulmonary artery pressure [mPAP], pulmonary vascular resistance [PVR]), and serum N-terminal pro-brain natriuretic peptide. Group comparisons were performed and Pearson correlation coefficients (r) were calculated.The [F]FDG uptake ratios in LP, RV, RV/LV, and PA, but not in LV, were found to be significantly higher in both patients with mPAP ≥25 mm Hg (P = 0.013, P = 0.006, P = 0.049, P = 0.002, P = 0.68, respectively) and with PVR ≥480 dyn·s/cm (P < 0.001, P = 0.045, P < 0.001, P < 0.001, P = 0.26, respectively). The [F]FDG uptake in these regions positively correlated also with mPAP, PVR, and N-terminal pro-brain natriuretic peptide. The SUVR of PA positively correlated with the SUVR of LP and RV (r = 0.55, r = 0.42, respectively).Pulmonary and cardiac [F]FDG uptake in PET imaging positively correlated with the presence and severity of PH in patients with end-stage pulmonary disease. Increased glucose metabolism in the central PAs seems to

  11. Prostate cancer nodal oligometastasis accurately assessed using prostate-specific membrane antigen positron emission tomography-computed tomography and confirmed histologically following robotic-assisted lymph node dissection

    PubMed Central

    O’Kane, Dermot B.; Lawrentschuk, Nathan; Bolton, Damien M.

    2016-01-01

    We herein present a case of a 76-year-old gentleman, where prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT) was used to accurately detect prostate cancer (PCa), pelvic lymph node (LN) metastasis in the setting of biochemical recurrence following definitive treatment for PCa. The positive PSMA PET-CT result was confirmed with histological examination of the involved pelvic LNs following pelvic LN dissection. PMID:27141207

  12. Review of cardiovascular imaging in the journal of nuclear cardiology in 2015. Part 1 of 2: Plaque imaging, positron emission tomography, computed tomography, and magnetic resonance.

    PubMed

    AlJaroudi, Wael A; Hage, Fadi G

    2016-02-01

    In 2015, many original articles pertaining to cardiovascular imaging with impressive quality were published in the Journal of Nuclear Cardiology. In a set of 2 articles, we provide an overview of these contributions to facilitate for the interested reader a quick review of the advancements that occurred in the field over this year. In this first article, we focus on arterial plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance imaging.

  13. Review of cardiovascular imaging in the journal of nuclear cardiology in 2015. Part 1 of 2: Plaque imaging, positron emission tomography, computed tomography, and magnetic resonance.

    PubMed

    AlJaroudi, Wael A; Hage, Fadi G

    2016-02-01

    In 2015, many original articles pertaining to cardiovascular imaging with impressive quality were published in the Journal of Nuclear Cardiology. In a set of 2 articles, we provide an overview of these contributions to facilitate for the interested reader a quick review of the advancements that occurred in the field over this year. In this first article, we focus on arterial plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance imaging. PMID:26542991

  14. 18F-fluorodeoxyglucose positron emission tomography-computed tomography finding of left gonadal vein thrombosis in a case of renal cell carcinoma.

    PubMed

    Narayan, Ravishwar; Ravishankar, Uma; Natarajan, Savita; Vohra, Sandeep

    2016-01-01

    Tumor thrombus from renal cell carcinoma is commonly reported in renal vein and inferior vena cava with a few reports of gonadal vein involvement. Here, we report a case of an elderly female who underwent fluorodeoxyglucose (FDG) positron emission tomography-computed tomography scan for initial staging of left renal cell carcinoma. Along with an FDG avid left renal mass lesion, scan also revealed FDG avid tumor thrombus in the entire length of the left gonadal vein.

  15. Rare case of isolated splenic metastases from gastric cancer detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Sivanesan, Balasubramanian; Shibu, Deepu; Shinto, Ajit Sugunan

    2013-04-01

    We report a rare case of isolated splenic metastasis from gastric cancer detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT). A 55-year-old man with gastric cancer 1 year post surgery, evaluated with PET/CT showed focal, intense uptake in the spleen, with no other abnormal findings. On splenectomy, the lesion was confirmed as metastasis from gastric cancer pathologically.

  16. Unilateral primary adrenal natural killer/T-cell lymphoma: Role of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography for staging and interim response assessment

    PubMed Central

    Kabnurkar, Rasika; Agrawal, Archi; Epari, Sridhar; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    Primary adrenal lymphoma (PAL) is a rare malignancy often involving bilateral adrenal glands. Diffuse large B-cell is the most common histological type. Unilateral presentation and T-cell/natural killer (T/NK) cell histological type is rarer. We report fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography scan findings in a case of unilateral T/NK cell PAL performed for staging and interim treatment response assessment. PMID:26917897

  17. Persistence of cerebral metabolic abnormalities in chronic schizophrenia as determined by positron emission tomography

    SciTech Connect

    Wolkin, A.; Jaeger, J.; Brodie, J.D.; Wolf, A.P.; Fowler, J.; Rotrosen, J.; Gomez-Mont, F.; Cancro, R.

    1985-05-01

    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.

  18. Development of radioiodinated receptor ligands for cerebral single photon emission tomography

    SciTech Connect

    Knapp, F.F. Jr.; McPherson, D.W.

    1992-01-01

    In the last decade the use of radiolabeled ligands for the imaging of cerebral receptors by emission computed tomography (ECT) has seen rapid growth. The opportunity to routinely perform cerebral single photon emission tomography (SPET) with iodine-123-labeled ligands depends on the availability of receptor ligands into which iodine can be introduced without decreasing the required high target receptor specificity. The use of iodine-123-labeled receptor-specific ligands also depends on the availability of high purity iodine-123 at reasonable costs and the necessary imaging instrumentation. In this paper, the development and current stage of evaluation of various iodine-123-labeled ligands for SPET imaging of dopaminergic, serotonergic and muscarinic acetylcholinergic receptor classes are discussed.

  19. Development of radioiodinated receptor ligands for cerebral single photon emission tomography

    SciTech Connect

    Knapp, F.F. Jr.; McPherson, D.W.

    1992-03-01

    In the last decade the use of radiolabeled ligands for the imaging of cerebral receptors by emission computed tomography (ECT) has seen rapid growth. The opportunity to routinely perform cerebral single photon emission tomography (SPET) with iodine-123-labeled ligands depends on the availability of receptor ligands into which iodine can be introduced without decreasing the required high target receptor specificity. The use of iodine-123-labeled receptor-specific ligands also depends on the availability of high purity iodine-123 at reasonable costs and the necessary imaging instrumentation. In this paper, the development and current stage of evaluation of various iodine-123-labeled ligands for SPET imaging of dopaminergic, serotonergic and muscarinic acetylcholinergic receptor classes are discussed.

  20. Single photon emission computed tomography in Alzheimer's disease. Abnormal iofetamine I 123 uptake reflects dementia severity

    SciTech Connect

    Johnson, K.A.; Holman, B.L.; Mueller, S.P.; Rosen, T.J.; English, R.; Nagel, J.S.; Growdon, J.H.

    1988-04-01

    To determine whether abnormalities in regional cerebral functional activity estimated by iofetamine hydrochloride I 123 and single photon emission computed tomography can be detected in mild or moderate as well as severe cases of Alzheimer's disease (AD), we performed iofetamine I 123-single photon emission computed tomography in 37 patients with probable AD (nine patients with mild, 18 patients with moderate, and ten patients with severe dementia) and nine age-matched control subjects. Iofetamine I 123 uptake was measured in right and left frontal, temporal, parietal, and occipital cortices. Mean (right and left) iofetamine I 123 activity was lowest in the parietal region of patients with AD and was significantly reduced in the other three regions compared with control subjects. Only in the parietal region was lower relative iofetamine I 123 activity associated with an impaired level of patient function and with cognitive deficit.

  1. {sup 18}F-Choline Positron Emission Tomography/Computed Tomography–Driven High-Dose Salvage Radiation Therapy in Patients With Biochemical Progression After Radical Prostatectomy: Feasibility Study in 60 Patients

    SciTech Connect

    D'Angelillo, Rolando M.; Sciuto, Rosa; Ramella, Sara; Papalia, Rocco; Jereczek-Fossa, Barbara A.; Trodella, Luca E.; Fiore, Michele; Gallucci, Michele; Maini, Carlo L.; Trodella, Lucio

    2014-10-01

    Purpose: To retrospectively review data of a cohort of patients with biochemical progression after radical prostatectomy, treated according to a uniform institutional treatment policy, to evaluate toxicity and feasibility of high-dose salvage radiation therapy (80 Gy). Methods and Materials: Data on 60 patients with biochemical progression after radical prostatectomy between January 2009 and September 2011 were reviewed. The median value of prostate-specific antigen before radiation therapy was 0.9 ng/mL. All patients at time of diagnosis of biochemical recurrence underwent dynamic {sup 18}F-choline positron emission tomography/computed tomography (PET/CT), which revealed in all cases a local recurrence. High-dose salvage radiation therapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT-positive area. Toxicity was recorded according to the Common Terminology Criteria for Adverse Events, version 3.0, scale. Results: Treatment was generally well tolerated: 54 patients (90%) completed salvage radiation therapy without any interruption. Gastrointestinal grade ≥2 acute toxicity was recorded in 6 patients (10%), whereas no patient experienced a grade ≥2 genitourinary toxicity. No grade 4 acute toxicity events were recorded. Only 1 patient (1.7%) experienced a grade 2 gastrointestinal late toxicity. With a mean follow-up of 31.2 months, 46 of 60 patients (76.6%) were free of recurrence. The 3-year biochemical progression-free survival rate was 72.5%. Conclusions: At early follow-up, {sup 18}F-choline PET/CT-driven high-dose salvage radiation therapy seems to be feasible and well tolerated, with a low rate of toxicity.

  2. Role of (18F) 2-fluoro-2-deoxyglucose positron emission tomography in upper gastrointestinal malignancies

    PubMed Central

    Smyth, Elizabeth C; Shah, Manish A

    2011-01-01

    The role of whole-body FDG [(18F) 2-fluoro-2-deoxyglucose] positron emission tomography (PET) scanning as an imaging modality in the management of patients with malignancy has evolved enormously over the past two decades. FDG-PET has demonstrated significant efficacy in the staging, prognostication and detection of occult metastatic disease in malignancies of the gastrointestinal tract, in addition to assessment of the response to cytotoxic chemotherapy in a more timely manner than has traditionally been possible by more conventional imaging tools. The sensitivity and specificity of FDG-PET for the detection and staging of malignancy depend not only on the site and size of the primary tumor and metastases, but also on histological cell type, reflecting underlying disparities in glucose metabolism. The metabolic response to neo-adjuvant chemotherapy or to chemo-radiotherapy in cancers of the gastro-esophageal junction or stomach has been demonstrated in several prospective studies to correlate significantly with both the histological tumor response to treatment and with consequent improvements in overall survival. This may offer a future paradigm of personalized treatment based on the PET response to chemotherapy. FDG-PET has been less successful in efforts to screen for and detect recurrent upper gastrointestinal malignancies, and in the detection of low volume metastatic peritoneal disease. Efforts to improve the accuracy of PET include the use of novel radiotracers such as (18F) FLT (3-deoxy-3-fluorothymidine) or 11C-choline, or fusion PET-CT with concurrent high-resolution computed tomography. This review focuses on the role of FDG-PET scanning in staging and response assessment in malignancies of the upper gastrointestinal tract, specifically gastric, esophageal and pancreas carcinoma. PMID:22171140

  3. Positron Emission Tomography and Magnetic Resonance Imaging of Cellular Inflammation in Patients with Abdominal Aortic Aneurysms

    PubMed Central

    McBride, O.M.B.; Joshi, N.V.; Robson, J.M.J.; MacGillivray, T.J.; Gray, C.D.; Fletcher, A.M.; Dweck, M.R.; van Beek, E.J.R.; Rudd, J.H.F.; Newby, D.E.; Semple, S.I.

    2016-01-01

    Objectives Inflammation is critical in the pathogenesis of abdominal aortic aneurysm (AAA) disease. Combined 18F-fludeoxyglucose (18F-FDG) positron emission tomography with computed tomography (PET-CT) and ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) are non-invasive methods of assessing tissue inflammation. The aim of this study was to compare these techniques in patients with AAA. Materials and methods Fifteen patients with asymptomatic AAA with diameter 46 ± 7 mm underwent PET-CT with 18F-FDG, and T2*-weighted MRI before and 24 hours after administration of USPIO. The PET-CT and MRI data were then co-registered. Standardised uptake values (SUVs) were calculated to measure 18F-FDG activity, and USPIO uptake was determined using the change in R2*. Comparisons between the techniques were made using a quadrant analysis and a voxel-by-voxel evaluation. Results When all areas of the aneurysm were evaluated, there was a modest correlation between the SUV on PET-CT and the change in R2* on USPIO-enhanced MRI (n = 70,345 voxels; r = .30; p < .0001). Although regions of increased 18F-FDG and USPIO uptake co-localised on occasion, this was infrequent (kappa statistic 0.074; 95% CI 0.026–0.122). 18F-FDG activity was commonly focused in the shoulder region whereas USPIO uptake was more apparent in the main body of the aneurysm. Maximum SUV was lower in patients with mural USPIO uptake. Conclusions Both 18F-FDG PET-CT and USPIO-MRI uptake identify vascular inflammation associated with AAA. Although they demonstrate a modest correlation, there are distinct differences in the pattern and distribution of uptake, suggesting a differential detection of macrophage glycolytic and phagocytic activity respectively. PMID:26919936

  4. High-speed digitization readout of silicon photomultipliers for time of flight positron emission tomography

    SciTech Connect

    Ronzhin, A.; Los, S.; Martens, M.; Ramberg, E.; Kim, H.; Chen, C.; Kao, C.; Niessen, K.; Zatserklyaniy, A.; Mazzillo, M.; Carbone, B.; /SGS Thomson, Catania

    2011-02-01

    We report on work to develop a system with about 100 picoseconds (ps) time resolution for time of flight positron emission tomography [TOF-PET]. The chosen photo detectors for the study were Silicon Photomultipliers (SiPM's). This study was based on extensive experience in studying timing properties of SiPM's. The readout of these devices used the commercial high speed digitizer DRS4. We applied different algorithms to get the best time resolution of 155 ps Guassian (sigma) for a LYSO crystal coupled to a SiPM. We consider the work as a first step in building a prototype TOF-PET module. The field of positron-emission-tomography (PET) has been rapidly developing. But there are significant limitations in how well current PET scanners can reconstruct images, related to how fast data can be acquired, how much volume they can image, and the spatial and temporal resolution of the generated photons. Typical modern scanners now include multiple rings of detectors, which can image a large volume of the patient. In this type of scanner, one can treat each ring as a separate detector and require coincidences only within the ring, or treat the entire region viewed by the scanner as a single 3 dimensional volume. This 3d technique has significantly better sensitivity since more photon pair trajectories are accepted. However, the scattering of photons within the volume of the patient, and the effect of random coincidences limits the technique. The advent of sub-nanosecond timing resolution detectors means that there is potentially much better rejection of scattered photon events and random coincidence events in the 3D technique. In addition, if the timing is good enough, then the origin of photons pairs can be determined better, resulting in improved spatial resolution - so called 'Time-of-Flight' PET, or TOF-PET. Currently a lot of activity has occurred in applications of SiPMs for TOF-PET. This is due to the devices very good time resolution, low profile, lack of high voltage

  5. High uptake in schneiderian papillomas of the maxillary sinus on positron-emission tomography using fluorodeoxyglucose.

    PubMed

    Lin, F Y; Genden, E M; Lawson, W L; Som, P; Kostakoglu, L

    2009-02-01

    Schneiderian papillomas are benign tumors of the nasal cavity and paranasal sinuses often asymptomatic in their early stages. We report a case of a maxillary sinus oncocytic schneiderian papilloma first detected by positron-emission tomography by using fluorodeoxyglucose (FDG). Schneiderian papillomas demonstrate increased FDG uptake, similar to that of other oncocytic tumors, making it important for otolaryngologists and radiologists to realize that high uptake of FDG does not necessarily indicate a malignant lesion. PMID:18768722

  6. Brain dopamine metabolism in patients with Parkinson's disease measured with positron emission tomography.

    PubMed Central

    Leenders, K L; Palmer, A J; Quinn, N; Clark, J C; Firnau, G; Garnett, E S; Nahmias, C; Jones, T; Marsden, C D

    1986-01-01

    L-[18F] fluorodopa was administered in trace amounts intravenously to healthy control subjects and to patients with Parkinson's disease. Striatal uptake of radioactivity was measured using positron emission tomography. The capacity of the striatum to retain tracer was severely impaired in patients compared to controls. This may reflect a reduction of striatal dopamine storage in Parkinson's disease. Patients showing the "on/off" phenomenon had an even greater decrease of striatal storage capacity. Images PMID:3091770

  7. Advances in Single-Photon Emission Computed Tomography Hardware and Software.

    PubMed

    Piccinelli, Marina; Garcia, Ernest V

    2016-02-01

    Nuclear imaging techniques remain today's most reliable modality for the assessment and quantification of myocardial perfusion. In recent years, the field has experienced tremendous progress both in terms of dedicated cameras for cardiac applications and software techniques for image reconstruction. The most recent advances in single-photon emission computed tomography hardware and software are reviewed, focusing on how these improvements have resulted in an even more powerful diagnostic tool with reduced injected radiation dose and acquisition time.

  8. Bimedial rectus hypermetabolism in convergence spasm as observed on positron emission tomography.

    PubMed

    Jeong, Seong-Hae; Oh, Young-Mi; Kim, Chae-Yong; Kim, Ji Soo

    2008-09-01

    A 52-year-old man developed vertical gaze palsy, convergence spasm, and convergence-retraction nystagmus due to glioblastoma of the right thalamus. 18F-fluorodeoxyglucose positron emission tomography (PET) inadvertently demonstrated markedly increased metabolism in the medial rectus muscles. The hypermetabolism indicates active contraction of these extraocular muscles due to excessive convergence drive attributed to inappropriate activation or disrupted inhibition of convergence neurons by the diencephalic lesion.

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

    SciTech Connect

    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.

  10. Evaluation of Glucose Uptake in Normal and Cancer Cell Lines by Positron Emission Tomography.

    PubMed

    Maddalena, Francesca; Lettini, Giacomo; Gallicchio, Rosj; Sisinni, Lorenza; Simeon, Vittorio; Nardelli, Anna; Venetucci, Angela Assunta; Storto, Giovanni; Landriscina, Matteo

    2015-01-01

    To date, there is no definitive demonstration of the utility of positron emission tomography (PET) in studying glucose metabolism in cultured cell lines. Thus, this study was designed to compare PET to more standardized methods for the quantitative assessment of glucose uptake in nontransformed and transformed living cells and to validate PET for metabolic studies in vitro. Human colon and breast carcinoma cell lines and mouse embryo fibroblasts were evaluated for [(18)F]fluorodeoxyglucose ([(18)F]FDG) uptake by PET and autoradiography and 2-deoxyglucose (2-DG) incorporation by colorimetric assay and analyzed for the radiotoxic effects of [(18)F]FDG and the expression levels of glucose transporters. Indeed, [(18)F]FDG incorporation on PET was comparable to [(18)F]FDG uptake by autoradiography and 2-DG incorporation by colorimetric assay, although radiotracer-based methods exhibited more pronounced differences between individual cell lines. As expected, these data correlated with glucose transporters 1 to 4 and hexokinase II expression in tumor cell lines and mouse fibroblasts. Notably, [(18)F]FDG incorporation resulted in low apoptotic rates, with fibroblasts being slightly more sensitive to radiotracer-induced cell death. The quantitative analysis of [(18)F]FDG uptake in living cells by PET represents a valuable and reproducible method to study tumor cell metabolism in vitro, being representative of the differences in the molecular profile of normal and tumor cell lines.

  11. Correlation between histological grade and positron emission tomography parameters in cervical carcinoma

    PubMed Central

    Mocciaro, Vanessa; Scollo, Paolo; Stefano, Alessandro; Gieri, Stefania; Russo, Giorgio; Scibilia, Giuseppe; Cosentino, Sebastiano; Murè, Gabriella; Baldari, Sara; Sabini, Maria Gabriella; Fraggetta, Filippo; Gilardi, Maria Carla; Ippolito, Massimo

    2016-01-01

    The aim of the present study was to evaluate the changes in cervical cancer glucose metabolism for different levels of cellular differentiation. The metabolic activity was measured by standardized uptake value (SUV), SUV normalized to lean body mass, metabolic tumor volume and total lesion glycolysis using fluorine-18 fluorodeoxyglucose positron emission tomography (PET). A correlation study of these values could be used to facilitate therapeutic choice and to improve clinical practice and outcome. This study considered 32 patients with diagnosed cervical cancers, at different International Federation of Gynecology and Obstetrics stages. Glucose metabolism was assessed by PET examination, and histological specimens were examined to determine their initial grade of differentiation. A correlation study of these values was evaluated. Histological examination showed that all cases were of squamous cell carcinoma. Regarding the differentiation of the tumor, 19 well- to moderately-differentiated tumors and 13 poorly-differentiated tumors were determined. Negative findings for correlations between metabolic parameters and initial grade of histological differentiation were found, and considering that histological grade has been shown to have no consistent prognostic value in cervical cancer treatment, PET imaging could play a significant role in cervical cancer prognosis. PMID:27446445

  12. Stable confinement of positron emission tomography and magnetic resonance agents within carbon nanotubes for bimodal imaging

    PubMed Central

    Cisneros, Brandon T; Law, Justin J; Matson, Michael L; Azhdarinia, Ali; Sevick-Muraca, Eva M; Wilson, Lon J

    2014-01-01

    Aims Simultaneous positron emission tomography/MRI has recently been introduced to the clinic and dual positron emission tomography/MRI probes are rare and of growing interest. We have developed a strategy for producing multimodal probes based on a carbon nanotube platform without the use of chelating ligands. Materials & methods Gd3+ and 64Cu2+ ions were loaded into ultra-short single-walled carbon nanotubes by sonication. Normal, tumor-free athymic nude mice were injected intravenously with the probe and imaged over 48 h. Results & conclusion The probe was stable for up to 24 h when challenged with phosphate-buffered saline and mouse serum. Positron emission tomography imaging also confirmed the stability of the probe in vivo for up to 48 h. The probe was quickly cleared from circulation, with enhanced accumulation in the lungs. Stable encapsulation of contrast agents within ultra-short single-walled carbon nanotubes represents a new strategy for the design of advanced imaging probes with variable multimodal imaging capabilities. PMID:24628687

  13. Positron Emission Tomography in Prostate Cancer: Summary of Systematic Reviews and Meta-Analysis

    PubMed Central

    Jadvar, Hossein

    2015-01-01

    Prostate cancer is a prevalent public health problem worldwide. Over the past decade, there has been tremendous research activity in the potential use of positron emission tomography with a number of radiotracers targeted to various biological aspects of this complex tumor. Systematic reviews and meta-analysis are important contributions to the relevant literature that summarize the evidence while reducing the effect of various sources of bias in the published data. The accumulation of relevant data in this clinical setting has recently provided the opportunity for systematic reviews. In this brief article, I summarize the published systematic reviews and meta-analysis of positron emission tomography in prostate cancer. Most robust evidence suggests a probable role for first-line use of positron emission tomography with radiolabeled choline in restating patients with biochemical relapse of prostate cancer with the diagnostic performance that appears to be positively associated with the serum prostate specific antigen level and velocity. Future systematic reviews will be needed for other emerging radiotracers such as those based on prostate specific membrane antigen and gastrin-releasing peptide receptor. PMID:26726317

  14. Targeted positron emission tomography imaging of CXCR4 expression in patients with acute myeloid leukemia

    PubMed Central

    Herhaus, Peter; Habringer, Stefan; Philipp-Abbrederis, Kathrin; Vag, Tibor; Gerngross, Carlos; Schottelius, Margret; Slotta-Huspenina, Julia; Steiger, Katja; Altmann, Torben; Weißer, Tanja; Steidle, Sabine; Schick, Markus; Jacobs, Laura; Slawska, Jolanta; Müller-Thomas, Catharina; Verbeek, Mareike; Subklewe, Marion; Peschel, Christian; Wester, Hans-Jürgen; Schwaiger, Markus; Götze, Katharina; Keller, Ulrich

    2016-01-01

    Acute myeloid leukemia originates from leukemia-initiating cells that reside in the protective bone marrow niche. CXCR4/CXCL12 interaction is crucially involved in recruitment and retention of leukemia-initiating cells within this niche. Various drugs targeting this pathway have entered clinical trials. To evaluate CXCR4 imaging in acute myeloid leukemia, we first tested CXCR4 expression in patient-derived primary blasts. Flow cytometry revealed that high blast counts in patients with acute myeloid leukemia correlate with high CXCR4 expression. The wide range of CXCR4 surface expression in patients was reflected in cell lines of acute myeloid leukemia. Next, we evaluated the CXCR4-specific peptide Pentixafor by positron emission tomography imaging in mice harboring CXCR4 positive and CXCR4 negative leukemia xenografts, and in 10 patients with active disease. [68Ga]Pentixafor-positron emission tomography showed specific measurable disease in murine CXCR4 positive xenografts, but not when CXCR4 was knocked out with CRISPR/Cas9 gene editing. Five of 10 patients showed tracer uptake correlating well with leukemia infiltration assessed by magnetic resonance imaging. The mean maximal standard uptake value was significantly higher in visually CXCR4 positive patients compared to CXCR4 negative patients. In summary, in vivo molecular CXCR4 imaging by means of positron emission tomography is feasible in acute myeloid leukemia. These data provide a framework for future diagnostic and theranostic approaches targeting the CXCR4/CXCL12-defined leukemia-initiating cell niche. PMID:27175029

  15. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

    NASA Astrophysics Data System (ADS)

    Christensen, A. N.; Rydhög, J. S.; Søndergaard, R. V.; Andresen, T. L.; Holm, S.; Munck Af Rosenschöld, P.; Conradsen, K.; Jølck, R. I.

    2016-05-01

    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-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive 106Ag, 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 (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively.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-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive 106Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The

  16. Insights Into Microcirculation Underlying Critical Limb Ischemia by Single-Photon Emission Computed Tomography

    PubMed Central

    Liu, Jung-Tung; Chang, Cheng-Siu; Su, Chen-Hsing; Li, Cho-Shun

    2015-01-01

    Abstract Perfusion difference is used as a parameter to evaluate microcirculation. This study aims to differentiate lower-limb perfusion insufficiency from neuropathy to prevent possible occurrence of failed back surgery syndrome (FBSS). Patients were retrospectively gathered from 134 FBSS cases diagnosed in the past 7 years. Up to 82 cases that were excluded from neuralgia by radiologic imaging, electrodiagnostic electromyography, and nerve conduction velocity were enrolled in this study. Perfusion difference was evaluated by single-photon emission computed tomography, and pain intensities were recorded via visual analog scale (VAS) score. Lower perfusion at the left leg comprises 51.2% (42 of 82) of the patients. The mean perfusion difference of the 82 patients was 0.86 ± 0.05 (range: 0.75–0.93). Patients with systemic vascular diseases exhibited significantly higher perfusion difference than that of patients without these related diseases (P < 0.05), except for renal insufficiency (P = 0.134). Significant correlation was observed between perfusion difference and VAS score (r = −0.78; P < 0.0001; n = 82). In this study, we presented perfusion difference as a parameter for evaluating microcirculation, which cannot be detected by ultrasonography or angiography. PMID:26166084

  17. Fluorine-18 fluorodeoxyglucose positron emission tomography imaging of T-lymphoblastic lymphoma patients

    PubMed Central

    Park, Jong Hoon; Pahk, Kisoo; Kim, Sungeun; Lim, Sang Moo; Cheon, Gi Jeong; Park, Yeon Hee; Lee, Seung-Sook; Choe, Jae Gol

    2016-01-01

    The purpose of the present study was to evaluate the fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings in patients with T-lymphoblastic lymphoma (T-LBL). In total, 9 patients with histopathologically confirmed T-LBL were included in the study. Bone marrow (BM) involvement and leukemic transformation (LT) were evaluated through iliac crest marrow biopsy and peripheral blood blast count. FDG-PET scans were performed at the initial pre-treatment point. Two experienced nuclear medicine physicians evaluated the FDG-PET images by visual analysis and using the maximum standardized uptake values (SUVmax) of the malignant lesions. Overall, 8 out 9 patients presented with BM involvement; 7 showed LT, while 1 showed BM involvement without LT. All involved T-LBL lesions were FDG-avid with variable uptake. The mean SUVmax was 6.4±3.3. T-LBL patients with BM involvement showed diffuse or nodular marrow uptake. In addition, all the patients with LT showed diffuse marrow FDG activity. However, the patient with BM involvement but no LT showed nodular FDG uptake in the marrow. In conclusion, the present study indicates that it is possible to use FDG-PET for the evaluation of the disease extent of T-LBL. Furthermore, the imaging technique could provide a diagnostic clue for determining BM involvement or LT. PMID:27446482

  18. Critical examination of the uniformity requirements for single-photon emission computed tomography.

    PubMed

    O'Connor, M K; Vermeersch, C

    1991-01-01

    It is generally recognized that single-photon emission computed tomography (SPECT) imposes very stringent requirements on gamma camera uniformity to prevent the occurrence of ring artifacts. The purpose of this study was to examine the relationship between nonuniformities in the planar data and the magnitude of the consequential ring artifacts in the transaxial data, and how the perception of these artifacts is influenced by factors such as reconstruction matrix size, reconstruction filter, and image noise. The study indicates that the relationship between ring artifact magnitude and image noise is essentially independent of the acquisition or reconstruction matrix sizes, but is strongly dependent upon the type of smoothing filter applied during the reconstruction process. Furthermore, the degree to which a ring artifact can be perceived above image noise is dependent on the size and location of the nonuniformity in the planar data, with small nonuniformities (1-2 pixels wide) close to the center of rotation being less perceptible than those further out (8-20 pixels). Small defects or nonuniformities close to the center of rotation are thought to cause the greatest potential corruption to tomographic data. The study indicates that such may not be the case. Hence the uniformity requirements for SPECT may be less demanding than was previously thought.

  19. Kinetic analysis of [11C]vorozole binding in the human brain with positron emission tomography.

    PubMed

    Logan, Jean; Kim, Sung Won; Pareto, Deborah; Telang, Frank; Wang, Gene-Jack; Fowler, Joanna S; Biegon, Anat

    2014-01-01

    Using positron emission tomography, we investigated the kinetics of [11C]vorozole ([11C]VOR), a radiotracer for the enzyme aromatase that catalyzes the last step in estrogen biosynthesis. Six subjects were scanned under baseline conditions followed by retest 2 weeks later. The retest was followed by a blocking study with 2.5 mg of the aromatase inhibitor letrozole. The binding potential (BP(A)ND) was estimated from a Lassen plot using the total tissue distribution volume (VT) for baseline and blocked. for the thalamus was found to be 15 times higher than that for the cerebellum. From the letrozole studies, we found that [11C]VOR exhibits a slow binding compartment (small k4) that has a nonspecific and a blockable component. Because of the sensitivity of VT to variations in k4, a common value was used for the four highest binding regions. We also considered the tissue uptake to plasma ratio for 60 to 90 minutes as an outcome measure. Using the ratio method, the difference between the highest and lowest was 2.4 compared to 3.5 for the VT. The ratio method underestimates the high regions but is less variable and may be more suitable for patient studies. Because of its kinetics and distribution, this tracer is not a candidate for a bolus infusion or reference tissue methods.

  20. Positron Emission Tomography to Assess the Outcome of Intraportal Islet Transplantation.

    PubMed

    Eriksson, Olof; Selvaraju, Ramkumar; Eich, Torsten; Willny, Mariam; Brismar, Torkel B; Carlbom, Lina; Ahlström, Håkan; Tufvesson, Gunnar; Lundgren, Torbjörn; Korsgren, Olle

    2016-09-01

    No imaging methodology currently exists to monitor viable islet mass after clinical intraportal islet transplantation. We investigated the potential of the endocrine positron emission tomography (PET) marker [(11)C]5-hydroxytryptophan ([(11)C]5-HTP) for this purpose. In a preclinical proof-of-concept study, the ex vivo and in vivo [(11)C]5-HTP signal was compared with the number of islets transplanted in rats. In a clinical study, human subjects with an intraportal islet graft (n = 8) underwent two [(11)C]5-HTP PET and MRI examinations 8 months apart. The tracer concentration in the liver as a whole, or in defined hotspots, was correlated to measurements of islet graft function. In rat, hepatic uptake of [(11)C]5-HTP correlated with the number of transplanted islets. In human subjects, uptake in hepatic hotspots showed a correlation with metabolic assessments of islet function. Change in hotspot standardized uptake value (SUV) predicted loss of graft function in one subject, whereas hotspot SUV was unchanged in subjects with stable graft function. The endocrine marker [(11)C]5-HTP thus shows a correlation between hepatic uptake and transplanted islet function and promise as a tool for noninvasive detection of viable islets. The evaluation procedure described can be used as a benchmark for novel agents targeting intraportally transplanted islets. PMID:27325286

  1. Static stabilometry, transcranial Doppler, and single photon emission computed tomography in patients with central dizziness.

    PubMed

    Woolley, S M; Rubin, A M; Chronis, C B; Dailey, V; Bork, C E; Gerard, G

    1994-11-01

    Previous studies have found that transcranial doppler (TCD) and single photon emission computed tomography (SPECT) are effective means of diagnosing cerebral blood flow disorders in patients with central dizziness whose etiology was unknown by standard audiologic and/or vestibular assessment techniques. Also, static stabilometry, which measures a person's standing center of pressure (COP) movements, has been used to distinguish between patients with central neurologic and peripheral vestibular disorders. The purpose of this retrospective study was to examine the relation between TCD, SPECT, and stabilometry in patients with central dizziness attributable to cerebral blood flow disorders. Stabilometry testing was conducted on 50 normal subjects and 31 subjects with dizziness, the latter group consisting of persons with cerebral dysautoregulation, migraines, and unknown etiology with negative or positive SPECT results. The results indicated that patients with cerebral dysautoregulation were not significantly different from normal subjects or the other three groups in their COP movements. The other three groups exhibited significantly higher COP movements than the normal subjects, particularly when visual inputs were compromised. Patients with negative SPECT results were significantly different in their COP movements from the other three groups of subjects with dizziness. These results suggest that the pattern of COP movements may be useful in identifying patients with postural dysfunctions whose etiology may then be detected by TCD and SPECT.

  2. Detection of neuronal damage in degenerative brain disease with cobalt-55 and positron emission tomography

    SciTech Connect

    Jansen, H.M.L.; Pruim, J.; Paans, A.M.J.

    1994-05-01

    We suggest Cobalt-55 (Co) as a Calcium (Ca)-marker to visualize Ca transport across the neuronal membrane. Elevation of intracellular Ca is closely linked with the process of neuronal cell-decay. Co-uptake is correlated with Ca-accumulation through divalent cation-permeable kainate (KA)-activated receptor-operated channels in the neuronal membrane. This hypothesis was studied with position emission tomography (PET) both in patients with a ischemic cerebro-vascular accident (CVA) and in patients with relapsing progressive multiple sclerosis (MS). Co-PET studies were performed in a dynamic mode (6 frames of 10 minutes) 20-25 hours after iv.-administration of 1-2 mCi Co. Regional specific accumulation irrespective of blood brain barrier (BBB) integrity in the (clinically appropriate) affected cerebral region could be demonstrated in CVA-patients, thus suggesting neuronal decay in (the early phase of) infarction. In MS, inhomogeneous cerebral distribution of Co was detected, in contrast to healthy volunteers. This suggests focal accumulation of Co in multiple spots of neuronal decay, possibly related to MS-lesions on MRI. In conclusion, Co-PET may prove to be a valuable tool for the early detection of neuronal decay not only in CVA and MS, but in other brain-pathology as well. The usefulness of Co-PET in imaging brain-tumors and myocardial ischemia has already been established.

  3. A New Positron Emission Tomography (PET) Radioligand for Imaging Sigma-1 Receptors in Living Subjects

    PubMed Central

    Zavaleta, Cristina L.; Nielsen, Carsten H.; Mesangeau, Christophe; Vuppala, Pradeep K.; Chan, Carmel; Avery, Bonnie A.; Fishback, James A.; Matsumoto, Rae R.; Gambhir, Sanjiv S.; McCurdy, Christopher R.; Chin, Frederick T.

    2014-01-01

    Sigma-1 receptor (S1R) radioligands have the potential to detect and monitor various neurological diseases. Herein we report the synthesis, radiofluorination and evaluation of a new S1R ligand 6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one ([18F]FTC-146, [18F]13). [18F]13 was synthesized by nucleophilic fluorination, affording a product with >99% radiochemical purity (RCP) and specific activity (SA) of 2.6 ± 1.2 Ci/Amol (n = 13) at end of synthesis (EOS). Positron emission tomography (PET) and ex vivo autoradiography studies of [18F]13 in mice showed high uptake of the radioligand in S1R rich regions of the brain. Pre treatment with 1 mg/kg haloperidol (2), non radioactive 13, or BD1047 (18) reduced the binding of [18F]13 in the brain at 60 min by 80%, 82% and 81% respectively, suggesting that [18F]13 accumulation in mouse brain represents specific binding to S1Rs. These results indicate that [18F]13 is a promising candidate radiotracer for further evaluation as a tool for studying S1Rs in living subjects. PMID:22853801

  4. A Novel Potential Positron Emission Tomography Imaging Agent for Vesicular Monoamine Transporter Type 2.

    PubMed

    Huang, Zih-Rou; Tsai, Chia-Ling; Huang, Ya-Yao; Shiue, Chyng-Yann; Tzen, Kai-Yuan; Yen, Ruoh-Fang; Hsin, Ling-Wei

    2016-01-01

    In the early 1990s, 9-(+)-11C-dihydrotetrabenazine (9-(+)-11C-DTBZ) was shown to be a useful positron emission tomography (PET) imaging agent for various neurodegenerative disorders. Here, we described the radiosynthesis and evaluation of the 9-(+)-11C-DTBZ analog, 10-(+)-11C-DTBZ, as a vesicular monoamine transporter 2 (VMAT2) imaging agent and compare it with 9-(+)-11C-DTBZ. 10-(+)-11C-DTBZ was obtained by 11C-MeI methylation with its 10 hydroxy precursor in the presence of 5 M NaOH. It had a slightly better average radiochemical yield of 35.3 ± 3.6% (decay-corrected to end of synthesis (EOS)) than did 9-(+)-11C-DTBZ (30.5 ± 2.3%). MicroPET studies showed that 10-(+)-11C-DTBZ had a striatum-to-cerebellum ratio of 3.74 ± 0.21 at 40 min post-injection, while the ratio of 9-(+)-11C-DTBZ was 2.50 ± 0.33. This indicated that 10-(+)-11C-DTBZ has a higher specific uptake in VMAT2-rich brain regions, and 10-(+)-11C-DTBZ may be a potential VMAT2 radioligand. Our experiment is the first study of 10-(+)-11C-DTBZ to include dynamic brain distribution in rat brains. PMID:27612194

  5. A Novel Potential Positron Emission Tomography Imaging Agent for Vesicular Monoamine Transporter Type 2

    PubMed Central

    Huang, Zih-Rou; Tsai, Chia-Ling; Huang, Ya-Yao; Shiue, Chyng-Yann; Tzen, Kai-Yuan; Yen, Ruoh-Fang; Hsin, Ling-Wei

    2016-01-01

    In the early 1990s, 9-(+)-11C-dihydrotetrabenazine (9-(+)-11C-DTBZ) was shown to be a useful positron emission tomography (PET) imaging agent for various neurodegenerative disorders. Here, we described the radiosynthesis and evaluation of the 9-(+)-11C-DTBZ analog, 10-(+)-11C-DTBZ, as a vesicular monoamine transporter 2 (VMAT2) imaging agent and compare it with 9-(+)-11C-DTBZ. 10-(+)-11C-DTBZ was obtained by 11C-MeI methylation with its 10 hydroxy precursor in the presence of 5 M NaOH. It had a slightly better average radiochemical yield of 35.3 ± 3.6% (decay-corrected to end of synthesis (EOS)) than did 9-(+)-11C-DTBZ (30.5 ± 2.3%). MicroPET studies showed that 10-(+)-11C-DTBZ had a striatum-to-cerebellum ratio of 3.74 ± 0.21 at 40 min post-injection, while the ratio of 9-(+)-11C-DTBZ was 2.50 ± 0.33. This indicated that 10-(+)-11C-DTBZ has a higher specific uptake in VMAT2-rich brain regions, and 10-(+)-11C-DTBZ may be a potential VMAT2 radioligand. Our experiment is the first study of 10-(+)-11C-DTBZ to include dynamic brain distribution in rat brains. PMID:27612194

  6. New Glucocyclic RGD Dimers for Positron Emission Tomography Imaging of Tumor Integrin Receptors.

    PubMed

    Lee, Ji Woong; Park, Ji-Ae; Lee, Yong Jin; Shin, Un Chol; Kim, Suhng Wook; Kim, Byung Il; Lim, Sang Moo; An, Gwang Il; Kim, Jung Young; Lee, Kyo Chul

    2016-08-01

    Most studies of radiolabeled arginine-glycine-aspartic acid (RGD) peptides have shown in vitro affinity for integrin ανβ3, allowing for the targeting of receptor-positive tumors in vivo. However, major differences have been found in the pharmacokinetic profiles of different radiolabeled RGD peptide analogs. The purposes of this study were to prepare (64)Cu-DOTA-gluco-E[c(RGDfK)]2 (R8), (64)Cu-NOTA-gluco-E[c(RGDfK)]2 (R9), and (64)Cu-NODAGA-gluco-E[c(RGDfK)]2 (R10) and compare their pharmacokinetics and tumor imaging properties using small-animal positron emission tomography (PET). All three compounds were produced with high specific activity within 10 minutes. The IC50 values were similar for all the substances, and their affinities were greater than that of c(RGDyK). R8, R9, and R10 were stable for 24 hours in human and mouse serums and showed high uptake in U87MG tumors with high tumor-to-blood ratios. Compared to the control, a cyclic RGD peptide dimer without glucosamine, R10, showed low uptake in the liver. Because of their good imaging qualities and improved pharmacokinetics, (64)Cu-labeled dimer RGD conjugates (R8, R9, and R10) may have potential applications as PET radiotracers. R9 (NOTA) with highly in vivo stability consequentially showed an improved PET tumor uptake than R8 (DOTA) or R10 (NODAGA). PMID:27403677

  7. Test-Retest Repeatability of Myocardial Blood Flow Measurements using Rubidium-82 Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Efseaff, Matthew

    Rubidium-82 positron emission tomography (PET) imaging has been proposed for routine myocardial blood flow (MBF) quantification. Few studies have investigated the test-retest repeatability of this method. Same-day repeatability of rest MBF imaging was optimized with a highly automated analysis program using image-derived input functions and a dual spillover correction (SOC). The effects of heterogeneous tracer infusion profiles and subject hemodynamics on test-retest repeatability were investigated at rest and during hyperemic stress. Factors affecting rest MBF repeatability included gender, suspected coronary artery disease, and dual SOC (p < 0.001). The best repeatability coefficient for same-day rest MBF was 0.20 mL/min/g using a six-minute scan-time, iterative reconstruction, dual SOC, resting rate-pressure-product (RPP) adjustment, and a left atrium image-derived input function. The serial study repeatabilities of the optimized protocol in subjects with homogeneous RPPs and tracer infusion profiles was 0.19 and 0.53 mL/min/g at rest and stress, and 0.95 for stress / rest myocardial flow reserve (MFR). Subjects with heterogeneous tracer infusion profiles and hemodynamic conditions had significantly less repeatable MBF measurements at rest, stress, and stress/rest flow reserve (p < 0.05).

  8. Value of Positron Emission Tomography/Computed Tomography (PET-CT) in Suspected Non-small Cell Lung Cancer Recurrence and Impact on Patient Management

    PubMed Central

    Beslic, Nermina; Sadija, Amera; Ceric, Timur; Milardovic, Renata; Ceric, Sejla; Cavaljuga, Semra

    2016-01-01

    Introduction: Positron emission tomography/computed tomography (PET-CT) is very sensitive for diagnosis of recurrent NSCLC and has a significant impact on change of management. Preliminary data suggest superiority of PET-CT comparing to CT alone for lung cancer restaging. Materials and methods: This is a retrospective study which aim is to validate usage of PET-CT in suspected non-small cell lung carcinoma recurrence and its impact on further patient management. Total number of 31 patients with non-small cell lung carcinoma and uncertain diagnosis of recurrent disease or its extent after routine clinical and CT work-up were enrolled in this study. Discussion: We found in our study that PET-CT diagnosed recurrent disease in 65% of patients who were previously presented with an indeterminante CT. In 85% of patients there were change in further management. Conclusion: We suggest that PET should be performed on patients who have suspected relapse after potentially curative treatment, particularly if active treatment is being considered. PET-CT improved the diagnosis of recurrent NSCLC and this resulted in a significant impact and change in further patient management. PMID:27708496

  9. Treatment of advanced solid tumours with NSAIDs: Correlation of quantitative monitoring of circulating tumour cells and positron emission tomography-computed tomography imaging

    PubMed Central

    Willecke-Hochmuth, Regina; Pachmann, Katharina; Drevs, Joachim

    2016-01-01

    The detection and characterisation of tumour-derived circulating epithelial tumor cells (CETCs) or circulating tumor cells (CTCs) have been a main focus of basic oncological research over previous years. Numerous studies in the past decade have shown that CTCs are a promising tool for the estimation of the risk for metastatic relapse. The present observational study describes treatment results using tumour imaging and the quantification of CTCs. A group of 14 patients with advanced carcinomas was followed during their anticancer treatments. CTC numbers were serially detected and treatment success was estimated by positron emission tomography-computed tomography. A connection was found between tumour remission and a decreasing CTC count in 83%, a connection between stable disease and stable CTC numbers in 78% and a connection between progressive disease (PD) and an increase in CTC count in 50% of cases. In the patients with PD, an incomplete response was observed affecting the CTCs, but not the solid region of the tumour. As a result of this study, it may be concluded that patients with solid tumours benefit from serial quantification of CTCs in addition to imaging, as this combination of techniques provides a more sensitive result than imaging alone. PMID:27588120

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

    SciTech Connect

    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.

  11. Imaging and modeling of flow in porous media using clinical nuclear emission tomography systems and computational fluid dynamics

    PubMed Central

    Boutchko, Rostyslav; Rayz, Vitaliy L.; Vandehey, Nicholas T.; O’Neil, James P.; Budinger, Thomas F.; Nico, Peter S.; Druhan, Jennifer L.; Saloner, David A.; Gullberg, Grant T.; Moses, William W.

    2014-01-01

    This paper presents experimental and modeling aspects of applying nuclear emission tomography to study fluid flow in laboratory packed porous media columns of the type frequently used in geophysics, geochemistry and hydrology research. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are used as non-invasive tools to obtain dynamic 3D images of radioactive tracer concentrations. Dynamic sequences obtained using 18F-FDG PET are used to trace flow through a 5 cm diameter × 20 cm tall sand packed column with and without an impermeable obstacle. In addition, a custom-made rotating column setup placed in a clinical two-headed SPECT camera is used to image 99mTc-DTPA tracer propagation in a through-flowing column (10 cm diameter × 30 cm tall) packed with recovered aquifer sediments. A computational fluid dynamics software package FLUENT is used to model the observed flow dynamics. Tracer distributions obtained in the simulations in the smaller column uniformly packed with sand and in the column with an obstacle are remarkably similar to the reconstructed images in the PET experiments. SPECT results demonstrate strongly non-uniform flow patterns for the larger column slurry-packed with sub-surface sediment and slow upward flow. In the numerical simulation of the SPECT study, two symmetric channels with increased permeability are prescribed along the column walls, which result in the emergence of two well-defined preferential flow paths. Methods and results of this work provide new opportunities in hydrologic and biogeochemical research. The primary target application for developed technologies is non-destructive, non-perturbing, quantitative imaging of flow dynamics within laboratory scale porous media systems. PMID:24917693

  12. Positron emission tomography in female patients with borderline personality disorder.

    PubMed

    Juengling, F D; Schmahl, C; Hesslinger, B; Ebert, D; Bremner, J D; Gostomzyk, J; Bohus, M; Lieb, K

    2003-01-01

    The pathology of Borderline personality disorder (BPD) is poorly understood and its biological basis remains largely unknown. One functional brain imaging study using [(18)F]Deoxyglucose-PET previously reported frontal and prefrontal hypometabolism. We studied brain metabolism at baseline in 12 medication-free female patients with BPD without current substance abuse or depression and 12 healthy female controls by [(18)F]Deoxyglucose-PET and statistical parametric mapping. We found significant frontal and prefrontal hypermetabolism in patients with BPD relative to controls as well as significant hypometabolism in the hippocampus and cuneus. This study demonstrated limbic and prefrontal dysfunction under resting conditions in patients with BPD by FDG-PET. Dysfunction in this network of brain regions, which has been implicated in the regulation of emotion, may underlie symptoms of BPD.

  13. Comparison of left ventricular ejection fraction values obtained using invasive contrast left ventriculography, two-dimensional echocardiography, and gated single-photon emission computed tomography

    PubMed Central

    Garg, Nadish; Dresser, Thomas; Aggarwal, Kul; Gupta, Vishal; Mittal, Mayank K; Alpert, Martin A

    2016-01-01

    Objectives: Left ventricular ejection fraction can be measured by a variety of invasive and non-invasive cardiac techniques. This study assesses the relation of three diagnostic modalities to each other in the measurement of left ventricular ejection fraction: invasive contrast left ventriculography, two-dimensional echocardiography, and quantitative gated single-photon emission computed tomography. Methods: Retrospective chart review was conducted on 58 patients hospitalized with chest pain, who underwent left ventricular ejection fraction evaluation using each of the aforementioned modalities within a 3-month period not interrupted by myocardial infarction or revascularization. Results: The mean left ventricular ejection fraction values were as follows: invasive contrast left ventriculography (0.44±0.15), two-dimensional echocardiography (0.46±0.13), and gated single-photon emission computed tomography (0.37±0.10). Correlations coefficients and associated p values were as follows: invasive contrast left ventriculography versus two-dimensional echocardiography (r=0.69, p<0.001), invasive contrast left ventriculography versus gated single-photon emission computed tomography (r=0.80, p<0.0001), and gated single-photon emission computed tomography versus two-dimensional echocardiography (r=0.69, p<0.001). Conclusion: Our results indicate that strong positive correlations exist among the three techniques studied. PMID:27621804

  14. Comparison of left ventricular ejection fraction values obtained using invasive contrast left ventriculography, two-dimensional echocardiography, and gated single-photon emission computed tomography

    PubMed Central

    Garg, Nadish; Dresser, Thomas; Aggarwal, Kul; Gupta, Vishal; Mittal, Mayank K; Alpert, Martin A

    2016-01-01

    Objectives: Left ventricular ejection fraction can be measured by a variety of invasive and non-invasive cardiac techniques. This study assesses the relation of three diagnostic modalities to each other in the measurement of left ventricular ejection fraction: invasive contrast left ventriculography, two-dimensional echocardiography, and quantitative gated single-photon emission computed tomography. Methods: Retrospective chart review was conducted on 58 patients hospitalized with chest pain, who underwent left ventricular ejection fraction evaluation using each of the aforementioned modalities within a 3-month period not interrupted by myocardial infarction or revascularization. Results: The mean left ventricular ejection fraction values were as follows: invasive contrast left ventriculography (0.44±0.15), two-dimensional echocardiography (0.46±0.13), and gated single-photon emission computed tomography (0.37±0.10). Correlations coefficients and associated p values were as follows: invasive contrast left ventriculography versus two-dimensional echocardiography (r=0.69, p<0.001), invasive contrast left ventriculography versus gated single-photon emission computed tomography (r=0.80, p<0.0001), and gated single-photon emission computed tomography versus two-dimensional echocardiography (r=0.69, p<0.001). Conclusion: Our results indicate that strong positive correlations exist among the three techniques studied.

  15. Prediction of positron emission tomography/computed tomography (PET/CT) positivity in patients with high-risk primary melanoma

    PubMed Central

    Danielsen, Maria; Kjaer, Andreas; Wu, Max; Martineau, Lea; Nosrati, Mehdi; Leong, Stanley PL; Sagebiel, Richard W; III, James R Miller; Kashani-Sabet, Mohammed

    2016-01-01

    Positron emission tomography/computed tomography (PET/CT) is an important tool to identify occult melanoma metastasis. To date, it is controversial which patients with primary cutaneous melanoma should have staging PET/CT. In this retrospective analysis of more than 800 consecutive patients with cutaneous melanoma, we sought to identify factors predictive of PET/CT positivity in the setting of newly-diagnosed high-risk primary melanoma to determine those patients most appropriate to undergo a PET/CT scan as part of their diagnostic work up. 167 patients with newly-diagnosed high-risk primary cutaneous melanoma underwent a PET/CT scan performed as part of their initial staging. Clinical and histologic factors were evaluated as possible predictors of melanoma metastasis identified on PET/CT scanning using both univariate and multivariate logistic regression. In all, 32 patients (19.2%) had a positive PET/CT finding of metastatic melanoma. In more than half of these patients (56.3%), PET/CT scanning identified disease that was not detectable on clinical examination. Mitotic rate, tumor thickness, lymphadenopathy, and bleeding were significantly predictive of PET/CT positivity. A combinatorial index constructed from these factors revealed a significant association between number of high-risk factors observed and prevalence of PET/CT positivity, which increased from 5.8% (with the presence of 0-2 factors) to 100.0%, when all four factors were present. These results indicate that combining clinical and histologic prognostic factors enables the identification of patients with a higher likelihood of a positive PET/CT scan. PMID:27766186

  16. Iterative reconstruction using a Monte Carlo based system transfer matrix for dedicated breast positron emission tomography

    SciTech Connect

    Saha, Krishnendu; Straus, Kenneth J.; Glick, Stephen J.; Chen, Yu.

    2014-08-28

    To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.

  17. Future imaging of atherosclerosis: molecular imaging of coronary atherosclerosis with 18F positron emission tomography

    PubMed Central

    Psaltis, Peter J.

    2016-01-01

    Atherosclerosis is characterized by the formation of complex atheroma lesions (plaques) in arteries that pose risk by their flow-limiting nature and propensity for rupture and thrombotic occlusion. It develops in the context of disturbances to lipid metabolism and immune response, with inflammation underpinning all stages of plaque formation, progression and rupture. As the primary disease process responsible for myocardial infarction, stroke and peripheral vascular disease, atherosclerosis is a leading cause of morbidity and mortality on a global scale. A precise understanding of its pathogenic mechanisms is therefore critically important. Integral to this is the role of vascular wall imaging. Over recent years, the rapidly evolving field of molecular imaging has begun to revolutionize our ability to image beyond just the anatomical substrate of vascular disease, and more dynamically assess its pathobiology. Nuclear imaging by positron emission tomography (PET) can target specific molecular and biological pathways involved in atherosclerosis, with the application of 18Fluoride PET imaging being widely studied for its potential to identify plaques that are vulnerable or high risk. In this review, we discuss the emergence of 18Fluoride PET as a promising modality for the assessment of coronary atherosclerosis, focusing on the strengths and limitations of the two main radionuclide tracers that have been investigated to date: 2-deoxy-2-(18F)fluoro-D-glucose (18F-FDG) and sodium 18F-fluoride (18F-NaF). PMID:27500093

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

    PubMed Central

    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

  19. Correlation of physical parameters during radiochemical synthesis of (18)F positron emission tomography radiopharmaceuticals.

    PubMed

    Tiwari, Anjani K; Varshney, Raunak; Kaushik, Aruna; Datta, Anupama; Singh, Lokendra; Mishra, Anil K

    2011-06-01

    Positron emission tomography is a highly specialized imaging technique using short-lived radiolabel substances to produce extremely high resolution images of the body's biological function. The (18)F(-) ion is produced via the (18)O(p,n)(18)F reaction using a silver target cell filled with 1.4 mL of enriched [(18)O] water. On a typical run, the target is irradiated for 45 minutes with 16.5 MeV protons (on target) and an average beam current of 5-45 mA. When the same reaction takes place with [(16)O] water [(13)N] Ammonia is produced as the primary product by the abstraction of hydrogen from water. This study investigated the physical parameters of medical cyclotron during the radiochemical process with induced radioactivity flux and mutual correlation of physical parameters for 16.5 MeV medical cyclotron at the INMAS Delhi, India. It is observed that by getting farther from the target, the relative number of low-energy neutrons increases while the overall flux of neutrons decreases. This is due to multiple scattering of high-energy neutrons in the walls and eventually absorption of low-energy neutrons. The other parameters are also linked with each other which are correlatable.

  20. An investigation into positron emission tomography contouring methods across two treatment planning systems

    SciTech Connect

    Young, Tony; Som, Seu; Sathiakumar, Chithradevi; Holloway, Lois

    2013-04-01

    Positron emission tomography (PET) imaging has been used to provide additional information regarding patient tumor location, size, and staging for radiotherapy treatment planning purposes. This additional information reduces interobserver variability and produces more consistent contouring. It is well recognized that different contouring methodology for PET data results in different contoured volumes. The goal of this study was to compare the difference in PET contouring methods for 2 different treatment planning systems using a phantom dataset and a series of patient datasets. Contouring methodology was compared on the ADAC Pinnacle Treatment Planning System and the CMS XiO Treatment Planning System. Contours were completed on the phantom and patient datasets using a number of PET contouring methods—the standardized uptake value 2.5 method, 30%, 40%, and 50% of the maximum uptake method and the signal to background ratio method. Differences of >15% were observed for PET-contoured volumes between the different treatment planning systems for the same data and the same PET contouring methodology. Contoured volume differences between treatment planning systems were caused by differences in data formatting and display and the different contouring tools available. Differences in treatment planning system as well as contouring methodology should be considered carefully in dose-volume contouring and reporting, especially between centers that may use different treatment planning systems or those that have several different treatment planning systems.

  1. Metabolizer in vivo of fullerenes and metallofullerenes by positron emission tomography.

    PubMed

    Li, Juan; Yang, Wenjiang; Cui, Rongli; Wang, Dongliang; Chang, Yanan; Gu, Weihong; Yin, Wenyan; Bai, Xue; Chen, Kui; Xia, Lin; Geng, Huan; Xing, Gengmei

    2016-04-15

    Fullerenes (C60) and metallofullerenes (Gd@C82) have similar chemical structure, but the bio-effects of both fullerene-based materials are distinct in vivo. Tracking organic carbon-based materials such as C60 and Gd@C82 is difficult in vivo due to the high content of carbon element in the living tissues themselves. In this study, the biodistribution and metabolism of fullerenes (C60 and Gd@C82) radiolabeled with (64)Cu were observed by positron emission tomography (PET). (64)Cu-C60 and (64)Cu-Gd@C82 were prepared using 1, 4, 7, 10-tetrakis (carbamoylmethyl)-1, 4, 7, 10-tetra-azacyclodo-decanes grafted on carbon cages as a chelator for (64)Cu, and were obtained rapidly with high radiochemical yield (≥90%). The new radio-conjugates were evaluated in vivo in the normal mouse model and tissue distribution by small animal PET/CT imaging and histology was carried out. The PET imaging, the biodistribution and the excretion of C60 and Gd@C82 indicated that C60 samples have higher blood retention and lower renal clearance than the Gd@C82 samples in vivo and suggested that the differences in metabolism and distribution in vivo were caused by the structural differences of the groups on the fullerene cages though there is chemical similarity between C60 and Gd@C82.

  2. Imaging Brain Metabolism and Pathology in Alzheimer’s Disease with Positron Emission Tomography

    PubMed Central

    Shokouhi, S; Claassen, D; Riddle, WR

    2014-01-01

    Current Positron Emission Tomography (PET) biomarkers for Alzheimer’s disease (AD) assess either neuronal function, or associated pathological features of this common neurodegenerative disease. The most widely accepted clinical PET tool for AD is 18-fluorodeoxyglucose PET (FDG-PET), which measures cerebral metabolic glucose utilization rate (CMRglc). FDG-PET is a marker of synaptic activity, neuronal function, and neuronal metabolic activity. AD is characterized by a distinct pattern of hypometabolism, as seen with the FDG images. This pattern can show variability across different subjects and is present before a patient is demented, specifically in amnestic mild cognitive impairment a clinical diagnosis defined as an intermediate state from normal aging to dementia. In addition to FDG PET, novel PET approaches assess known pathological hallmarks of AD including extracellular amyloid-beta plaques (Aβ) and intracellular neurofibrillary tangles composed of tau fibrils. Already, amyloid PET imaging is a tool that allows in vivo imaging of extracellular beta-amyloid levels. Efforts to bring tau imaging into clinical use continue, but this approach is hampered by the intracellular nature of tau protein deposition, subsequent weak radiotracer binding, and low image contrast. Several new candidate probes for tau-specific PET imaging are currently available but have not found their way into broad clinical applications. This study gives an overview of the most recent PET-based neuroimaging techniques for AD. We place special emphasis on PET data analysis and interpretation techniques, as well as radiochemistry for imaging metabolism and assessing Aβ and tau pathology. PMID:25343059

  3. List-mode image reconstruction for positron emission tomography using tetrahedral voxels

    NASA Astrophysics Data System (ADS)

    Gillam, John E.; Angelis, Georgios I.; Meikle, Steven R.

    2016-09-01

    Image space decomposition based on tetrahedral voxels are interesting candidates for use in emission tomography. Tetrahedral voxels provide many of the advantages of point clouds with irregular spacing, such as being intrinsically multi-resolution, yet they also serve as a volumetric partition of the image space and so are comparable to more standard cubic voxels. Additionally, non-rigid displacement fields can be applied to the tetrahedral mesh in a straight-forward manner. So far studies incorporating tetrahedral decomposition of the image space have concentrated on pre-calculated, node-based, system matrix elements which reduces the flexibility of the tetrahedral approach and the capacity to accurately define regions of interest. Here, a list-mode on-the-fly calculation of the system matrix elements is described using a tetrahedral decomposition of the image space and volumetric elements—voxels. The algorithm is demonstrated in the context of awake animal PET which may require both rigid and non-rigid motion compensation, as well as quantification within small regions of the brain. This approach allows accurate, event based, motion compensation including non-rigid deformations.

  4. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    NASA Astrophysics Data System (ADS)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-11-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5× {{10}-6} is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.

  5. Iterative reconstruction using a Monte Carlo based system transfer matrix for dedicated breast positron emission tomography

    NASA Astrophysics Data System (ADS)

    Saha, Krishnendu; Straus, Kenneth J.; Chen, Yu.; Glick, Stephen J.

    2014-08-01

    To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.

  6. Metabolizer in vivo of fullerenes and metallofullerenes by positron emission tomography

    NASA Astrophysics Data System (ADS)

    Li, Juan; Yang, Wenjiang; Cui, Rongli; Wang, Dongliang; Chang, Yanan; Gu, Weihong; Yin, Wenyan; Bai, Xue; Chen, Kui; Xia, Lin; Geng, Huan; Xing, Gengmei

    2016-04-01

    Fullerenes (C60) and metallofullerenes (Gd@C82) have similar chemical structure, but the bio-effects of both fullerene-based materials are distinct in vivo. Tracking organic carbon-based materials such as C60 and Gd@C82 is difficult in vivo due to the high content of carbon element in the living tissues themselves. In this study, the biodistribution and metabolism of fullerenes (C60 and Gd@C82) radiolabeled with 64Cu were observed by positron emission tomography (PET). 64Cu-C60 and 64Cu-Gd@C82 were prepared using 1, 4, 7, 10-tetrakis (carbamoylmethyl)-1, 4, 7, 10-tetra-azacyclodo-decanes grafted on carbon cages as a chelator for 64Cu, and were obtained rapidly with high radiochemical yield (≥90%). The new radio-conjugates were evaluated in vivo in the normal mouse model and tissue distribution by small animal PET/CT imaging and histology was carried out. The PET imaging, the biodistribution and the excretion of C60 and Gd@C82 indicated that C60 samples have higher blood retention and lower renal clearance than the Gd@C82 samples in vivo and suggested that the differences in metabolism and distribution in vivo were caused by the structural differences of the groups on the fullerene cages though there is chemical similarity between C60 and Gd@C82.

  7. Amyloid and metabolic positron emission tomography imaging of cognitively normal adults with Alzheimer's parents.

    PubMed

    Mosconi, Lisa; Rinne, Juha O; Tsui, Wai H; Murray, John; Li, Yi; Glodzik, Lidia; McHugh, Pauline; Williams, Schantel; Cummings, Megan; Pirraglia, Elizabeth; Goldsmith, Stanley J; Vallabhajosula, Shankar; Scheinin, Noora; Viljanen, Tapio; Någren, Kjell; de Leon, Mony J

    2013-01-01

    This study examines the relationship between fibrillar beta-amyloid (Aβ) deposition and reduced glucose metabolism, a proxy for neuronal dysfunction, in cognitively normal (NL) individuals with a parent affected by late-onset Alzheimer's disease (AD). Forty-seven 40-80-year-old NL received positron emission tomography (PET) with (11)C-Pittsburgh compound B (PiB) and 18F-fluoro-2-deoxy-d-glucose (FDG). These included 19 NL with a maternal history (MH), 12 NL with a paternal history (PH), and 16 NL with negative family history of AD (NH). Automated regions of interest, statistical parametric mapping, voxel-wise intermodality correlations, and logistic regressions were used to examine cerebral-to-cerebellar PiB and FDG standardized uptake value ratios across groups. The MH group showed higher PiB retention and lower metabolism in AD regions compared with NH and PH, which were negatively correlated in posterior cingulate, frontal, and parieto-temporal regions (Pearson r ≤ -0.57, p ≤ 0.05). No correlations were observed in NH and PH. The combination of Aβ deposition and metabolism yielded accuracy ≥ 69% for MH vs. NH and ≥ 71% for MH vs. PH, with relative risk = 1.9-5.1 (p values < 0.005). NL individuals with AD-affected mothers show co-occurring Aβ increases and hypometabolism in AD-vulnerable regions, suggesting an increased risk for AD.

  8. Imaging muscarinic cholinergic receptors using I-123-paraiododexetimide and emission computed tomography

    SciTech Connect

    Frost, J.J.; Wilson, A.A.; Dannals, R.F.; Ravert, H.T.; Smith, A.C.; Wagner, H.N. Jr.

    1985-05-01

    Dexetimide is a high affinity muscarinic cholinergic receptor (MR) antagonist which binds preferentially to MR in vivo. The corresponding optical isomer of dexetimide is levetimide (LEV) which binds to MR with a thousand-fold lower affinity. Paraiododexetimide (IDEX) has an affinity slightly less than dexetimide (KD = 2.7 nM). Following the administration of I-125 IDEX (10 ..mu..g/kg,IV) to mice high radioactivity concentrations in the striatum and cerebral cortex and a low radioactivity concentration in the cerebellum were observed; this distribution corresponds to the known distribution of MR in the brain. Following the injection of I-125-ILEV a low and uniform radioactivity concentration was observed throughout the brain. Preliminary imaging studies using an Anger camera and I-123-IDEX in a baboon showed high radioactivity in the brain and parotid gland. The radioactivity in the parotid gland diminished with time whereas the radioactivity in the brain increased over the 90 min. imaging period, which suggests high affinity binding to MR in the brain. These results demonstrate the feasibility of imaging MR using single photon emission computed tomography and I-123-IDEX.

  9. (18)F-Labeling of Mannan for Inflammation Research with Positron Emission Tomography.

    PubMed

    Li, Xiang-Guo; Hagert, Cecilia; Siitonen, Riikka; Virtanen, Helena; Sareila, Outi; Liljenbäck, Heidi; Tuisku, Jouni; Knuuti, Juhani; Bergman, Jörgen; Holmdahl, Rikard; Roivainen, Anne

    2016-09-01

    Recently mannan from Saccharomyces cerevisiae has been shown to be able to induce psoriasis and psoriatic arthritis in mice, and the phenotypes resemble the corresponding human diseases. To investigate the pathological processes, we set out to label mannan with fluorine-18 ((18)F) and study the (18)F-labeled mannan in vitro and in vivo with positron emission tomography (PET). Accordingly, mannan has been transformed into (18)F-fluoromannan with (18)F-bicyclo[6.1.0]nonyne. In mouse aorta, the binding of [(18)F]fluoromannan to the atherosclerotic lesions was clearly visualized and was significantly higher compared to blocking assays (P < 0.001) or healthy mouse aorta (P < 0.001). In healthy rats the [(18)F]fluoromannan radioactivity accumulated largely in the macrophage-rich organs such as liver, spleen, and bone marrow and the excess excreted in urine. Furthermore, the corresponding (19)F-labeled mannan has been used to induce psoriasis and psoriatic arthritis in mice, which indicates that the biological function of mannan is preserved after the chemical modifications. PMID:27660685

  10. Future imaging of atherosclerosis: molecular imaging of coronary atherosclerosis with (18)F positron emission tomography.

    PubMed

    Scherer, Daniel J; Psaltis, Peter J

    2016-08-01

    Atherosclerosis is characterized by the formation of complex atheroma lesions (plaques) in arteries that pose risk by their flow-limiting nature and propensity for rupture and thrombotic occlusion. It develops in the context of disturbances to lipid metabolism and immune response, with inflammation underpinning all stages of plaque formation, progression and rupture. As the primary disease process responsible for myocardial infarction, stroke and peripheral vascular disease, atherosclerosis is a leading cause of morbidity and mortality on a global scale. A precise understanding of its pathogenic mechanisms is therefore critically important. Integral to this is the role of vascular wall imaging. Over recent years, the rapidly evolving field of molecular imaging has begun to revolutionize our ability to image beyond just the anatomical substrate of vascular disease, and more dynamically assess its pathobiology. Nuclear imaging by positron emission tomography (PET) can target specific molecular and biological pathways involved in atherosclerosis, with the application of (18)Fluoride PET imaging being widely studied for its potential to identify plaques that are vulnerable or high risk. In this review, we discuss the emergence of (18)Fluoride PET as a promising modality for the assessment of coronary atherosclerosis, focusing on the strengths and limitations of the two main radionuclide tracers that have been investigated to date: 2-deoxy-2-((18)F)fluoro-D-glucose ((18)F-FDG) and sodium (18)F-fluoride ((18)F-NaF). PMID:27500093

  11. Speech disorders in olivopontocerebellar atrophy correlate with positron emission tomography findings

    SciTech Connect

    Kluin, K.J.; Gilman, S.; Markel, D.S.; Koeppe, R.A.; Rosenthal, G.; Junck, L.

    1988-06-01

    We compared the severity of ataxic and spastic dysarthria with local cerebral metabolic rates for glucose (lCMRGlc) in 30 patients with olivopontocerebellar atrophy (OPCA). Perceptual analysis was used to examine the speech disorders, and rating scales were devised to quantitate the degree of ataxia and spasticity in the speech of each patient. lCMRGlc was measured with /sup 18/F-2-fluoro-2-deoxy-D-glucose and positron emission tomography (PET). PET studies revealed marked hypometabolism in the cerebellar hemispheres, cerebellar vermis, and brainstem of OPCA patients compared with 30 control subjects. With data normalized to the cerebral cortex, a significant inverse correlation was found between the severity of ataxia in speech and the lCMRGlc within the cerebellar vermis, cerebellar hemispheres, and brainstem, but not within the thalamus. No significant correlation was found between the severity of spasticity in speech and lCMRGlc in any of these structures. The findings support the view that the severity of ataxia in speech in OPCA is related to the functional activity of the cerebellum and its connections in the brainstem.

  12. Regional brain hematocrit in stroke by single photon emission computed tomography imaging

    SciTech Connect

    Loutfi, I.; Frackowiak, R.S.; Myers, M.J.; Lavender, J.P.

    1987-01-01

    Nineteen studies on 18 subjects were performed by single photon emission computed tomography (SPECT) of the head after the successive intravenous administration of a plasma label (/sup 99m/Tc-human serum albumin (HSA)) and /sup 99m/Tc-labeled autologous red blood cells (RBC). Two sets of cerebral tomographic sections were generated: for cerebral /sup 99m/Tc-HSA alone and for combined /sup 99m/Tc-HSA and /sup 99m/Tc-RBC. By relating counts in regions of interest from the cerebral tomograms to counts from blood samples obtained during each tomographic acquisition, regional cerebral haematocrit (Hct) was calculated by the application of a simple formula. Results show 1) lower cerebral Hct than venous Hct (ratio of HCT brain/Hct venous 0.65-0.90) in all subjects, and 2) comparison between right and left hemisphere Hct in 3/3 normal subjects, 6/6 patients with transient ischaemic attacks and 3/8 patients with stroke showed no significant difference. However, in 3/8 patients with stroke (most recent strokes) significant differences were found, the higher Hct value corresponding to the affected side.

  13. A fast rebinning algorithm for 3D positron emission tomography using John's equation

    NASA Astrophysics Data System (ADS)

    Defrise, Michel; Liu, Xuan

    1999-08-01

    Volume imaging in positron emission tomography (PET) requires the inversion of the three-dimensional (3D) x-ray transform. The usual solution to this problem is based on 3D filtered-backprojection (FBP), but is slow. Alternative methods have been proposed which factor the 3D data into independent 2D data sets corresponding to the 2D Radon transforms of a stack of parallel slices. Each slice is then reconstructed using 2D FBP. These so-called rebinning methods are numerically efficient but are approximate. In this paper a new exact rebinning method is derived by exploiting the fact that the 3D x-ray transform of a function is the solution to the second-order partial differential equation first studied by John. The method is proposed for two sampling schemes, one corresponding to a pair of infinite plane detectors and another one corresponding to a cylindrical multi-ring PET scanner. The new FORE-J algorithm has been implemented for this latter geometry and was compared with the approximate Fourier rebinning algorithm FORE and with another exact rebinning algorithm, FOREX. Results with simulated data demonstrate a significant improvement in accuracy compared to FORE, while the reconstruction time is doubled. Compared to FOREX, the FORE-J algorithm is slightly less accurate but more than three times faster.

  14. Development of a treatment planning system for BNCT based on positron emission tomography data: preliminary results

    NASA Astrophysics Data System (ADS)

    Cerullo, N.; Daquino, G. G.; Muzi, L.; Esposito, J.

    2004-01-01

    Present standard treatment planning (TP) for glioblastoma multiforme (GBM - a kind of brain tumor), used in all boron neutron capture therapy (BNCT) trials, requires the construction (based on CT and/or MRI images) of a 3D model of the patient head, in which several regions, corresponding to different anatomical structures, are identified. The model is then employed by a computer code to simulate radiation transport in human tissues. The assumption is always made that considering a single value of boron concentration for each specific region will not lead to significant errors in dose computation. The concentration values are estimated "indirectly", on the basis of previous experience and blood sample analysis. This paper describes an original approach, with the introduction of data on the in vivo boron distribution, acquired by a positron emission tomography (PET) scan after labeling the BPA (borono-phenylalanine) with the positron emitter 18F. The feasibility of this approach was first tested with good results using the code CARONTE. Now a complete TPS is under development. The main features of the first version of this code are described and the results of a preliminary study are presented. Significant differences in dose computation arise when the two different approaches ("standard" and "PET-based") are applied to the TP of the same GBM case.

  15. Effect of Harderian adenectomy on the statistical analyses of mouse brain imaging using positron emission tomography.

    PubMed

    Kim, Minsoo; Woo, Sang-Keun; Yu, Jung Woo; Lee, Yong Jin; Kim, Kyeong Min; Kang, Joo Hyun; Eom, Kidong; Nahm, Sang-Soep

    2014-01-01

    Positron emission tomography (PET) using 2-deoxy-2-[(18)F] fluoro-D-glucose (FDG) as a radioactive tracer is a useful technique for in vivo brain imaging. However, the anatomical and physiological features of the Harderian gland limit the use of FDG-PET imaging in the mouse brain. The gland shows strong FDG uptake, which in turn results in distorted PET images of the frontal brain region. The purpose of this study was to determine if a simple surgical procedure to remove the Harderian gland prior to PET imaging of mouse brains could reduce or eliminate FDG uptake. Measurement of FDG uptake in unilaterally adenectomized mice showed that the radioactive signal emitted from the intact Harderian gland distorts frontal brain region images. Spatial parametric measurement analysis demonstrated that the presence of the Harderian gland could prevent accurate assessment of brain PET imaging. Bilateral Harderian adenectomy efficiently eliminated unwanted radioactive signal spillover into the frontal brain region beginning on postoperative Day 10. Harderian adenectomy did not cause any post-operative complications during the experimental period. These findings demonstrate the benefits of performing a Harderian adenectomy prior to PET imaging of mouse brains.

  16. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography.

    PubMed

    Christensen, A N; Rydhög, J S; Søndergaard, R V; Andresen, T L; Holm, S; Munck Af Rosenschöld, P; Conradsen, K; Jølck, R I

    2016-06-01

    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-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive (106)Ag, 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 (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively. PMID:27174233

  17. Assessing tumor hypoxia by positron emission tomography with Cu-ATSM.

    PubMed

    Holland, J P; Lewis, J S; Dehdashti, F

    2009-04-01

    For the last several decades, hypoxia has been recognized to be one of the key factors in tumor aggression and an important impediment to local and distant control of malignant tumors. In addition, hypoxia is a major cause of failure of both radiation therapy and chemotherapy. It has been shown that hypoxia is an independent negative prognostic factor for patient outcome in various solid tumors. Clinical studies using polarographic oxygen electrodes, as a tool for measuring hypoxia, were the first to demonstrate the presence of hypoxia in human tumors and its association with poor prognosis. However, this method is invasive and has technical limitations that prevent its routine clinical use. Over the years, imaging as a noninvasive method has attracted a lot of attention and several radiotracers have been developed for noninvasive evaluation of hypoxia. One of the most promising radiotracers is the copper(II) complex of diacetyl-2,3-bis(N(4)-methyl-3-thiosemicarbazonato) ligand (Cu-ATSM) for imaging with positron emission tomography. In this review, the preclinical evaluation of Cu-ATSM as well as its clinical value in several solid tumors will be discussed.

  18. Positron emission tomography to assess hypoxia and perfusion in lung cancer

    PubMed Central

    Verwer, Eline E; Boellaard, Ronald; van der Veldt, Astrid AM

    2014-01-01

    In lung cancer, tumor hypoxia is a characteristic feature, which is associated with a poor prognosis and resistance to both radiation therapy and chemotherapy. As the development of tumor hypoxia is associated with decreased perfusion, perfusion measurements provide more insight into the relation between hypoxia and perfusion in malignant tumors. Positron emission tomography (PET) is a highly sensitive nuclear imaging technique that is suited for non-invasive in vivo monitoring of dynamic processes including hypoxia and its associated parameter perfusion. The PET technique enables quantitative assessment of hypoxia and perfusion in tumors. To this end, consecutive PET scans can be performed in one scan session. Using different hypoxia tracers, PET imaging may provide insight into the prognostic significance of hypoxia and perfusion in lung cancer. In addition, PET studies may play an important role in various stages of personalized medicine, as these may help to select patients for specific treatments including radiation therapy, hypoxia modifying therapies, and antiangiogenic strategies. In addition, specific PET tracers can be applied for monitoring therapy. The present review provides an overview of the clinical applications of PET to measure hypoxia and perfusion in lung cancer. Available PET tracers and their characteristics as well as the applications of combined hypoxia and perfusion PET imaging are discussed. PMID:25493221

  19. Positron Emission Tomography Imaging of Cancer Biology: Current Status and Future Prospects

    PubMed Central

    Chen, Kai; Chen, Xiaoyuan

    2011-01-01

    Positron emission tomography (PET) is one of the most rapidly growing areas of medical imaging, with many applications in the clinical management of patients with cancer. The principal goal of PET imaging is to visualize, characterize, and measure biological processes at the cellular, subcellular, and molecular levels in living subjects using noninvasive procedures. PET imaging takes advantage of the traditional diagnostic imaging techniques and introduces positron-emitting probes to determine the expression of indicative molecular targets at different stages of cancer progression. Although [18F]fluorodeoxyglucose ([18F]FDG)-PET has been widely utilized for staging and restaging of cancer, evaluation of response to treatment, differentiation of post-therapy alterations from residual or recurrent tumor, and assessment of prognosis, [18F]FDG is not a target-specific PET tracer. Over the last decade, numerous target-specific PET tracers have been developed and evaluated in preclinical and clinical studies. This review provides an overview of the current status and trends in the development of non-[18F]FDG PET probes in oncology and their application in the investigation of cancer biology. PMID:21362517

  20. Radiolabelling diverse positron emission tomography (PET) tracers using a single digital microfluidic reactor chip.

    PubMed

    Chen, Supin; Javed, Muhammad Rashed; Kim, Hee-Kwon; Lei, Jack; Lazari, Mark; Shah, Gaurav J; van Dam, R Michael; Keng, Pei-Yuin; Kim, Chang-Jin C J

    2014-03-01

    Radiotracer synthesis is an ideal application for microfluidics because only nanogram quantities are needed for positron emission tomography (PET) imaging. Thousands of radiotracers have been developed in research settings but only a few are readily available, severely limiting the biological problems that can be studied in vivo via PET. We report the development of an electrowetting-on-dielectric (EWOD) digital microfluidic chip that can synthesize a variety of (18)F-labeled tracers targeting a range of biological processes by confirming complete syntheses of four radiotracers: a sugar, a DNA nucleoside, a protein labelling compound, and a neurotransmitter. The chip employs concentric multifunctional electrodes that are used for heating, temperature sensing, and EWOD actuation. All of the key synthesis steps for each of the four (18)F-labeled tracers are demonstrated and characterized with the chip: concentration of fluoride ion, solvent exchange, and chemical reactions. The obtained fluorination efficiencies of 90-95% are comparable to, or greater than, those achieved by conventional approaches.

  1. (18)F-Labeling of Mannan for Inflammation Research with Positron Emission Tomography.

    PubMed

    Li, Xiang-Guo; Hagert, Cecilia; Siitonen, Riikka; Virtanen, Helena; Sareila, Outi; Liljenbäck, Heidi; Tuisku, Jouni; Knuuti, Juhani; Bergman, Jörgen; Holmdahl, Rikard; Roivainen, Anne

    2016-09-01

    Recently mannan from Saccharomyces cerevisiae has been shown to be able to induce psoriasis and psoriatic arthritis in mice, and the phenotypes resemble the corresponding human diseases. To investigate the pathological processes, we set out to label mannan with fluorine-18 ((18)F) and study the (18)F-labeled mannan in vitro and in vivo with positron emission tomography (PET). Accordingly, mannan has been transformed into (18)F-fluoromannan with (18)F-bicyclo[6.1.0]nonyne. In mouse aorta, the binding of [(18)F]fluoromannan to the atherosclerotic lesions was clearly visualized and was significantly higher compared to blocking assays (P < 0.001) or healthy mouse aorta (P < 0.001). In healthy rats the [(18)F]fluoromannan radioactivity accumulated largely in the macrophage-rich organs such as liver, spleen, and bone marrow and the excess excreted in urine. Furthermore, the corresponding (19)F-labeled mannan has been used to induce psoriasis and psoriatic arthritis in mice, which indicates that the biological function of mannan is preserved after the chemical modifications.

  2. Glucose utilization in a patient with hepatoma and hypoglycemia. Assessment by a positron emission tomography.

    PubMed Central

    Eastman, R C; Carson, R E; Orloff, D G; Cochran, C S; Perdue, J F; Rechler, M M; Lanau, F; Roberts, C T; Shapiro, J; Roth, J

    1992-01-01

    Tumor glucose use in patients with non-islet-cell tumors has been difficult to measure, particularly in hepatoma, because of hepatic involvement by neoplasm. We studied a patient with nonhepatic recurrence of hepatoma after successful liver transplantation. Tumor tissue contained messenger RNA for insulin-like growth factor-II (IGF-II), and circulating high molecular weight components and E-peptide of IGF-II were increased. Glucose use measured by isotope dilution with [3-3H]glucose was 7.94 mg/kg fat-free mass per min, and splanchnic glucose production was 0.93 mg/kg fat-free mass per min. Glucose uptake and glucose model parameters were independently measured in tissues by positron emission tomography with 18F-fluoro-2-deoxy-D-glucose. Glucose uptake by heart muscle, liver, skeletal muscle, and neoplasm accounted for 0.8, 14, 44, and 15% of total glucose use, respectively. Model parameters in liver and neoplasm were not significantly different, and glucose transport and phosphorylation were twofold and fourfold greater than in muscle. This suggests that circulating IGF-II-like proteins are partial insulin agonists, and that hypoglycemia in hepatoma with IGF-II production is predominantly due to glucose uptake by skeletal muscle and suppression of glucose production. PMID:1318326

  3. Iterative reconstruction using a Monte Carlo based system transfer matrix for dedicated breast positron emission tomography.

    PubMed

    Saha, Krishnendu; Straus, Kenneth J; Chen, Yu; Glick, Stephen J

    2014-08-28

    To maximize sensitivity, it is desirable that ring Positron Emission Tomography (PET) systems dedicated for imaging the breast have a small bore. Unfortunately, due to parallax error this causes substantial degradation in spatial resolution for objects near the periphery of the breast. In this work, a framework for computing and incorporating an accurate system matrix into iterative reconstruction is presented in an effort to reduce spatial resolution degradation towards the periphery of the breast. The GATE Monte Carlo Simulation software was utilized to accurately model the system matrix for a breast PET system. A strategy for increasing the count statistics in the system matrix computation and for reducing the system element storage space was used by calculating only a subset of matrix elements and then estimating the rest of the elements by using the geometric symmetry of the cylindrical scanner. To implement this strategy, polar voxel basis functions were used to represent the object, resulting in a block-circulant system matrix. Simulation studies using a breast PET scanner model with ring geometry demonstrated improved contrast at 45% reduced noise level and 1.5 to 3 times resolution performance improvement when compared to MLEM reconstruction using a simple line-integral model. The GATE based system matrix reconstruction technique promises to improve resolution and noise performance and reduce image distortion at FOV periphery compared to line-integral based system matrix reconstruction.

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

    PubMed

    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

  5. Biological Response of Positron Emission Tomography Scan Exposure and Adaptive Response in Humans

    PubMed Central

    Schnarr, Kara; Carter, Timothy F.; Gillis, Daniel; Webber, Colin; Dayes, Ian; Dolling, Joanna A.; Gulenchyn, Karen; Boreham, Douglas R.

    2015-01-01

    The biological effects of exposure to radioactive fluorodeoxyglucose (18F-FDG) were investigated in the lymphocytes of patients undergoing positron emission tomography (PET) procedures. Low-dose, radiation-induced cellular responses were measured using 3 different end points: (1) apoptosis; (2) chromosome aberrations; and (3) γH2AX foci formation. The results showed no significant change in lymphocyte apoptosis, or chromosome aberrations, as a result of in vivo 18F-FDG exposure, and there was no evidence the PET scan modified the apoptotic response of lymphocytes to a subsequent 2 Gy in vitro challenge irradiation. However, lymphocytes sampled from patients following a PET scan showed an average of 22.86% fewer chromosome breaks and 39.16% fewer dicentrics after a subsequent 2 Gy in vitro challenge irradiation. The effect of 18F-FDG exposure on phosphorylation of histone H2AX (γH2AX) in lymphocytes of patients showed a varied response between individuals. The relationship between γH2AX foci formation and increasing activity of 18F-FDG was not directly proportional to dose. This variation is most likely attributed to differences in the factors that combine to constitute an individual’s radiation response. In summary, the results of this study indicate18F-FDG PET scans may not be detrimental but can elicit variable responses between individuals and can modify cellular response to subsequent radiation exposures. PMID:26740810

  6. Dictionary learning for data recovery in positron emission tomography.

    PubMed

    Valiollahzadeh, SeyyedMajid; Clark, John W; Mawlawi, Osama

    2015-08-01

    Compressed sensing (CS) aims to recover images from fewer measurements than that governed by the Nyquist sampling theorem. Most CS methods use analytical predefined sparsifying domains such as total variation, wavelets, curvelets, and finite transforms to perform this task. In this study, we evaluated the use of dictionary learning (DL) as a sparsifying domain to reconstruct PET images from partially sampled data, and compared the results to the partially and fully sampled image (baseline).A CS model based on learning an adaptive dictionary over image patches was developed to recover missing observations in PET data acquisition. The recovery was done iteratively in two steps: a dictionary learning step and an image reconstruction step. Two experiments were performed to evaluate the proposed CS recovery algorithm: an IEC phantom study and five patient studies. In each case, 11% of the detectors of a GE PET/CT system were removed and the acquired sinogram data were recovered using the proposed DL algorithm. The recovered images (DL) as well as the partially sampled images (with detector gaps) for both experiments were then compared to the baseline. Comparisons were done by calculating RMSE, contrast recovery and SNR in ROIs drawn in the background, and spheres of the phantom as well as patient lesions.For the phantom experiment, the RMSE for the DL recovered images were 5.8% when compared with the baseline images while it was 17.5% for the partially sampled images. In the patients' studies, RMSE for the DL recovered images were 3.8%, while it was 11.3% for the partially sampled images. Our proposed CS with DL is a good approach to recover partially sampled PET data. This approach has implications toward reducing scanner cost while maintaining accurate PET image quantification.

  7. Dictionary learning for data recovery in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Valiollahzadeh, SeyyedMajid; Clark, John W., Jr.; Mawlawi, Osama

    2015-08-01

    Compressed sensing (CS) aims to recover images from fewer measurements than that governed by the Nyquist sampling theorem. Most CS methods use analytical predefined sparsifying domains such as total variation, wavelets, curvelets, and finite transforms to perform this task. In this study, we evaluated the use of dictionary learning (DL) as a sparsifying domain to reconstruct PET images from partially sampled data, and compared the results to the partially and fully sampled image (baseline). A CS model based on learning an adaptive dictionary over image patches was developed to recover missing observations in PET data acquisition. The recovery was done iteratively in two steps: a dictionary learning step and an image reconstruction step. Two experiments were performed to evaluate the proposed CS recovery algorithm: an IEC phantom study and five patient studies. In each case, 11% of the detectors of a GE PET/CT system were removed and the acquired sinogram data were recovered using the proposed DL algorithm. The recovered images (DL) as well as the partially sampled images (with detector gaps) for both experiments were then compared to the baseline. Comparisons were done by calculating RMSE, contrast recovery and SNR in ROIs drawn in the background, and spheres of the phantom as well as patient lesions. For the phantom experiment, the RMSE for the DL recovered images were 5.8% when compared with the baseline images while it was 17.5% for the partially sampled images. In the patients’ studies, RMSE for the DL recovered images were 3.8%, while it was 11.3% for the partially sampled images. Our proposed CS with DL is a good approach to recover partially sampled PET data. This approach has implications toward reducing scanner cost while maintaining accurate PET image quantification.

  8. Positron Emission Tomography (PET): Towards Time of Flight

    SciTech Connect

    Karp, Joel

    2004-09-29

    PET is a powerful imaging tool that is being used to study cancer, using a variety of tracers to measure physiological processes including glucose metabolism, cell proliferation, and hypoxia in tumor cells. As the utilization of PET has grown in the last several years, it has become clear that improved lesion detection and quantification are critical goals for cancer studies. Although physical performance of the current generation of PET scanners has improved recently, there are limitations especially for heavy patients where attenuation and scatter effects are increased. We are investigating new scintillation detectors, scanner designs, and image processing algorithms in order to overcome these limitations and improve performance. In particular, we are studying scanner designs that would incorporate scintillators with improved energy and timing resolution. Improved energy resolution helps to reduce scattered radiation, and improved timing resolution makes it feasible to incorporate the time-of-flight information between the two coincident gamma rays into the image reconstruction algorithm, a technique that improves signal-to-noise. Results of recent experiments and computer simulations will be shown to demonstrate these potential improvements.

  9. Positron emission tomography for measurement of copper fluxes in live organisms.

    PubMed

    Peng, Fangyu

    2014-05-01

    Copper is an essential nutrient for the physiology of live organisms, but excessive copper can be harmful. Copper radioisotopes are used for measurement of copper fluxes in live organisms using a radioactivity assay of body fluids or whole-body positron emission tomography (PET). Hybrid positron emission tomography-computed tomography (PET/CT) is a versatile tool for real-time measurement of copper fluxes combining the high sensitivity and quantification capability of PET and the superior spatial resolution of CT for anatomic localization of radioactive tracer activity. Kinetic analysis of copper metabolism in the liver and extrahepatic tissues of Atp7b(-/-) knockout mice, a mouse model of Wilson's disease, demonstrated the feasibility of measuring copper fluxes in live organisms with PET/CT using copper-64 chloride ((64) CuCl2 ) as a radioactive tracer ((64) CuCl2 -PET/CT). (64) CuCl2 -PET/CT holds potential as a useful tool for the diagnosis of inherited and acquired human copper metabolism disorders and for monitoring the effects of copper-modulating therapy.

  10. Bayesian reconstruction and use of anatomical a priori information for emission tomography

    SciTech Connect

    Bowsher, J.E.; Johnson, V.E.; Turkington, T.G.; Jaszczak, R.J.; Floyd, C.E. Jr.; Coleman, R.E.

    1996-10-01

    A Bayesian method is presented for simultaneously segmenting and reconstructing emission computed tomography (ECT) images and for incorporating high-resolution, anatomical information into those reconstructions. The anatomical information is often available from other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). The Bayesian procedure models the ECT radiopharmaceutical distribution as consisting of regions, such that radiopharmaceutical activity is similar throughout each region. It estimates the number of regions, the mean activity of each region, and the region classification and mean activity of each voxel. Anatomical information is incorporated by assigning higher prior probabilities to ECT segmentations in which each ECT region stays within a single anatomical region. This approach is effective because anatomical tissue type often strongly influences radiopharmaceutical uptake. The Bayesian procedure is evaluated using physically acquired single-photon emission computed tomography (SPECT) projection data and MRI for the three-dimensional (3-D) Hoffman brain phantom. A clinically realistic count level is used. A cold lesion within the brain phantom is created during the SPECT scan but not during the MRI to demonstrate that the estimation procedure can detect ECT structure that is not present anatomically.

  11. Positron Emission Tomography-Guided, Focal-Dose Escalation Using Intensity-Modulated Radiotherapy for Head and Neck Cancer

    SciTech Connect

    Madani, Indira . E-mail: indira@krtkg1.ugent.be; Duthoy, Wim; Derie, Cristina R.N.; De Gersem, Werner Ir.; Boterberg, Tom; Saerens, Micky; Jacobs, Filip Ir.; Gregoire, Vincent; Lonneux, Max; Vakaet, Luc; Vanderstraeten, Barbara; Bauters, Wouter; Bonte, Katrien; Thierens, Hubert; Neve, Wilfried de

    2007-05-01

    Purpose: To assess the feasibility of intensity-modulated radiotherapy (IMRT) using positron emission tomography (PET)-guided dose escalation, and to determine the maximum tolerated dose in head and neck cancer. Methods and Materials: A Phase I clinical trial was designed to escalate the dose limited to the [{sup 18}-F]fluoro-2-deoxy-D-glucose positron emission tomography ({sup 18}F-FDG-PET)-delineated subvolume within the gross tumor volume. Positron emission tomography scanning was performed in the treatment position. Intensity-modulated radiotherapy with an upfront simultaneously integrated boost was employed. Two dose levels were planned: 25 Gy (level I) and 30 Gy (level II), delivered in 10 fractions. Standard IMRT was applied for the remaining 22 fractions of 2.16 Gy. Results: Between 2003 and 2005, 41 patients were enrolled, with 23 at dose level I, and 18 at dose level II; 39 patients completed the planned therapy. The median follow-up for surviving patients was 14 months. Two cases of dose-limiting toxicity occurred at dose level I (Grade 4 dermitis and Grade 4 dysphagia). One treatment-related death at dose level II halted the study. Complete response was observed in 18 of 21 (86%) and 13 of 16 (81%) evaluated patients at dose levels I and II (p < 0.7), respectively, with actuarial 1-year local control at 85% and 87% (p n.s.), and 1-year overall survival at 82% and 54% (p = 0.06), at dose levels I and II, respectively. In 4 of 9 patients, the site of relapse was in the boosted {sup 18}F-FDG-PET-delineated region. Conclusions: For head and neck cancer, PET-guided dose escalation appears to be well-tolerated. The maximum tolerated dose was not reached at the investigated dose levels.

  12. F-18 deoxyglucose and stress N-13 ammonia positron emission tomography in anterior wall healed myocardial infarction

    SciTech Connect

    Fudo, T.; Kambara, H.; Hashimoto, T.; Hayashi, M.; Nohara, R.; Tamaki, N.; Yonekura, Y.; Senda, M.; Konishi, J.; Kawai, C.

    1988-06-01

    To evaluate myocardial blood flow and glucose utilization, N-13 ammonia (NH3) and F-18 deoxyglucose positron emission tomography scanning was performed in 22 patients with previous anterior wall myocardial infarction, using a high-resolution, multi-slice, whole-body scanner. The N-13 ammonia study was performed at rest and after exercise. The F-18 deoxyglucose study was performed at rest after fasting greater than 5 hours. The N-13 ammonia study revealed a hypoperfused area in 19 of the 22 patients (86%), that corresponded to the infarcted regions as diagnosed by electrocardiography, coronary arteriography and left ventriculography (21 patients). The hypoperfused areas expanded after exercise in 16 of 22 patients (73%). F-18 deoxyglucose uptake was observed in these hypoperfused areas, especially in patients with hypokinetic wall motion on left ventriculography and in exercise-induced hypoperfused areas. However, positron emission tomography demonstrated diffuse uptake of F-18 deoxyglucose in 3 of 8 patients with dyskinetic wall motion. Thus, metabolically active myocardium in infarcted areas or periinfarct ischemia can be visualized with F-18 deoxyglucose and stress N-13 ammonia studies.

  13. The Marinesco-Sjoegren syndrome examined by computed tomography, magnetic resonance, and sup 18 F-2-fluoro-2-deoxy-D-glucose and positron emission tomography

    SciTech Connect

    Bromberg, M.B.; Junck, L.; Gebarski, S.S.; McLean, M.J.; Gilman, S. )

    1990-11-01

    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

  14. Development of robotic plasma radiochemical assays for positron emission tomography

    SciTech Connect

    Alexoff, D.L.; Shea, C.; Fowler, J.S.; Gatley, S.J.; Schlyer, D.J.

    1995-12-01

    A commercial laboratory robot system (Zymate PyTechnology II Laboratory Automation System; Zymark Corporation, Hopkinton, MA) was interfaced to standard and custom laboratory equipment and programmed to perform rapid radiochemical analyses for quantitative PET studies. A Zymark XP robot arm was used to carry out the determination of unchanged (parent) radiotracer in plasma using only solid phase extraction methods. Robotic throughput for the assay of parent radiotracer in plasma is 4--6 samples/hour depending on the radiotracer. Robotic assays of parent compound in plasma were validated for the radiotracers [{sup 11}C]Benztropine, [{sup 11}C]cocaine, [{sup 11}C]clorgyline, [{sup 11}C]deprenyl, [{sup 11}C]methadone, [{sup 11}C]methylphenidate, [{sup 11}C]raclorpride, and [{sup 11}C]SR46349B. A simple robot-assisted methods development strategy has been implemented to facilitate the automation of plasma assays of new radiotracers.

  15. Influence of slice overlap on positron emission tomography image quality

    NASA Astrophysics Data System (ADS)

    McKeown, Clare; Gillen, Gerry; Dempsey, Mary Frances; Findlay, Caroline

    2016-02-01

    PET scans use overlapping acquisition beds to correct for reduced sensitivity at bed edges. The optimum overlap size for the General Electric (GE) Discovery 690 has not been established. This study assesses how image quality is affected by slice overlap. Efficacy of 23% overlaps (recommended by GE) and 49% overlaps (maximum possible overlap) were specifically assessed. European Association of Nuclear Medicine (EANM) guidelines for calculating minimum injected activities based on overlap size were also reviewed. A uniform flood phantom was used to assess noise (coefficient of variation, (COV)) and voxel accuracy (activity concentrations, Bq ml-1). A NEMA (National Electrical Manufacturers Association) body phantom with hot/cold spheres in a background activity was used to assess contrast recovery coefficients (CRCs) and signal to noise ratios (SNR). Different overlap sizes and sphere-to-background ratios were assessed. COVs for 49% and 23% overlaps were 9% and 13% respectively. This increased noise was difficult to visualise on the 23% overlap images. Mean voxel activity concentrations were not affected by overlap size. No clinically significant differences in CRCs were observed. However, visibility and SNR of small, low contrast spheres (⩽13 mm diameter, 2:1 sphere to background ratio) may be affected by overlap size in low count studies if they are located in the overlap area. There was minimal detectable influence on image quality in terms of noise, mean activity concentrations or mean CRCs when comparing 23% overlap with 49% overlap. Detectability of small, low contrast lesions may be affected in low count studies—however, this is a worst-case scenario. The marginal benefits of increasing overlap from 23% to 49% are likely to be offset by increased patient scan times. A 23% overlap is therefore appropriate for clinical use. An amendment to EANM guidelines for calculating injected activities is also proposed which better reflects the effect overlap size has

  16. Signal transduction images in human brain by positron emission tomography

    SciTech Connect

    Imahori, Y.; Fujii, R.; Ueda, S.

    1994-05-01

    Analysis of changes in intracellular signal transduction will provide clear images of the projected target neurons. We have recently developed a technique which allows second-messenger imaging of changes in intracellular signal transduction which is activated in parallel with phosphoinositide (PI) turnover. Using carbon-11-labeled 1,2-diacylglycerol (DAG), we have recently succeeded in making an image of intracellular signal transduction during the course of synaptic transmission in human brains. When five healthy volunteers were examined by this technique, they had high activity in the associate field, in particular the prefrontal area. In the absence of paradigm loading, the associate field was unilaterally active, and human subjects showed predominant activity in the right prefrontal area. Activation of the ipsilateral supraorbital region and the superior temporal area was also seen at the same time. In conclusion, no previous study has directly demonstrated the unilateral predominance of the activity in the associate fields (projected target area) and the accompanying areas. Unlike the conventional positron-labeled compounds which did not permit visualization of activation of the associate fields, our technique can measure the PI turnover, as a postsynaptic response, and thus provide clear images of the projected target nerve cells in relation to higher cortical function in human brain.

  17. Head sinuses, melon, and jaws of bottlenose dolphins, Tursiops truncatus, observed with computed tomography structural and single photon emission computed tomography functional imaging

    NASA Astrophysics Data System (ADS)

    Ridgway, Sam; Houser, Dorian; Finneran, James J.; Carder, Don; van Bonn, William; Smith, Cynthia; Hoh, Carl; Corbeil, Jacqueline; Mattrey, Robert

    2003-04-01

    The head sinuses, melon, and lower jaws of dolphins have been studied extensively with various methods including radiography, chemical analysis, and imaging of dead specimens. Here we report the first structural and functional imaging of live dolphins. Two animals were imaged, one male and one female. Computed tomography (CT) revealed extensive air cavities posterior and medial to the ear as well as between the ear and sound-producing nasal structures. Single photon emission computed tomography (SPECT) employing 50 mCi of the intravenously injected ligand technetium [Tc-99m] biscisate (Neurolite) revealed extensive and uptake in the core of the melon as well as near the pan bone area of the lower jaw. Count density on SPECT images was four times greater in melon as in the surrounding tissue and blubber layer suggesting that the melon is an active rather than a passive tissue. Since the dolphin temporal bone is not attached to the skull except by fibrous suspensions, the air cavities medial and posterior to the ear as well as the abutment of the temporal bone, to the acoustic fat bodies of each lower jaw, should be considered in modeling the mechanism of sound transmission from the environment to the dolphin ear.

  18. Detection of bone marrow involvement in newly diagnosed post-transplant lymphoproliferative disorder: (18)F-fluorodeoxyglucose positron emission tomography/computed tomography versus bone marrow biopsy.

    PubMed

    Gheysens, Olivier; Thielemans, Sanne; Morscio, Julie; Boeckx, Nancy; Goffin, Karolien E; Deroose, Christophe M; Sagaert, Xavier; Wlodarska, Iwona; Verhoef, Gregor; Dierickx, Daan; Tousseyn, Thomas

    2016-10-01

    Detecting bone marrow involvement (BMI) in lymphoma is important as it adversely affects stage. Bone marrow biopsy (BMB) remains the standard to detect BMI but is prone to sampling error. We retrospectively investigated whether (18)F-fluorodeoxyglucose positron emission tomography with computed tomography ((18)F-FDG-PET/CT) could identify BMI in patients with post-transplant lymphoproliferative disorder (PTLD) with sufficient accuracy in comparison with staging BMB. Twenty-five patients diagnosed with PTLD who underwent (18)F-FDG-PET/CT and BMB within one month were evaluated. Based on our criteria, six patients (24%) were considered positive for BMI on (18)F-FDG-PET/CT compared to one by BMB. Although we cannot completely exclude false positive results on (18)F-FDG-PET/CT, our data indicate a significantly higher sensitivity of (18)F-FDG-PET/CT compared to BMB (100% vs 17%) but similar specificity. These data confirm the high diagnostic performance of (18)F-FDG-PET/CT for detecting BMI, but prospective studies are needed to determine whether (18)F-FDG-PET/CT could indeed replace staging BMB in PTLD.

  19. The Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Bone Lesions of Undetermined Origin.

    PubMed

    Tamam, Cuneyt; Tamam, Muge; Mulazimoglu, Mehmet

    2016-01-01

    The aim of the current study was to determine the diagnostic accuracy of whole-body fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in detecting carcinoma of unknown primary (CUP) with bone metastases. We evaluated 87 patients who were referred to FDG-PET/CT imaging and reported to have skeletal lesions with suspicion of malignancy. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. The median survival rate was measured to evaluate the prognostic value of the FDG-PET/CT findings. In the search for a primary, FDG-PET/CT findings correctly diagnosed lesions as the site of the primary true positive (TP) in 64 (73%) cases, 4 (5%) findings diagnosed no site of a primary, and none were subsequently proven to be true negative (TN); 14 (16%) diagnoses were false positive (FP) and 5 (6%) diagnoses were false negative (FN). Life expectancy was between 2 months and 25 months. Whole-body FDG-PET/CT imaging may be a useful method in assessing the bone lesions with suspicion of bone metastases. PMID:27134563

  20. The predictive role of interim positron emission tomography for Hodgkin lymphoma treatment outcome is confirmed using the interpretation criteria of the Deauville five-point scale

    PubMed Central

    Gallamini, Andrea; Barrington, Sally F.; Biggi, Alberto; Chauvie, Stephane; Kostakoglu, Lale; Gregianin, Michele; Meignan, Michel; Mikhaeel, George N.; Loft, Annika; Zaucha, Jan M.; Seymour, John F.; Hofman, Michael S.; Rigacci, Luigi; Pulsoni, Alessandro; Coleman, Morton; Dann, Eldad J.; Trentin, Livio; Casasnovas, Olivier; Rusconi, Chiara; Brice, Pauline; Bolis, Silvia; Viviani, Simonetta; Salvi, Flavia; Luminari, Stefano; Hutchings, Martin

    2014-01-01

    A retrospective, international, multicenter study was undertaken to assess: (i) the prognostic role of ‘interim’ positron emission tomography performed during treatment with doxorubicin, bleomycin, vinblastine and dacarbazine in patients with Hodgkin lymphoma; and (ii) the reproducibility of the Deauville five-point scale for the interpretation of interim positron emission tomography scan. Two hundred and sixty patients with newly diagnosed Hodgkin lymphoma were enrolled. Fifty-three patients with early unfavorable and 207 with advanced-stage disease were treated with doxorubicin, bleomycin, vinblastine and dacarbazine ± involved-field or consolidation radiotherapy. Positron emission tomography scan was performed at baseline and after two cycles of chemotherapy. Treatment was not changed according to the results of the interim scan. An international panel of six expert reviewers independently reported the scans using the Deauville five-point scale, blinded to treatment outcome. Forty-five scans were scored as positive (17.3%) and 215 (82.7%) as negative. After a median follow up of 37.0 (2–110) months, 252 patients are alive and eight have died. The 3-year progression-free survival rate was 83% for the whole study population, 28% for patients with interim positive scans and 95% for patients with interim negative scans (P<0.0001). The sensitivity, specificity, and negative and positive predictive values of interim positron emission tomography scans for predicting treatment outcome were 0.73, 0.94, 0.94 and 0.73, respectively. Binary concordance amongst reviewers was good (Cohen’s kappa 0.69–0.84). In conclusion, the prognostic role and validity of the Deauville five-point scale for interpretation of interim positron emission tomography scans have been confirmed by the present study. PMID:24658820

  1. The predictive role of interim positron emission tomography for Hodgkin lymphoma treatment outcome is confirmed using the interpretation criteria of the Deauville five-point scale.

    PubMed

    Gallamini, Andrea; Barrington, Sally F; Biggi, Alberto; Chauvie, Stephane; Kostakoglu, Lale; Gregianin, Michele; Meignan, Michel; Mikhaeel, George N; Loft, Annika; Zaucha, Jan M; Seymour, John F; Hofman, Michael S; Rigacci, Luigi; Pulsoni, Alessandro; Coleman, Morton; Dann, Eldad J; Trentin, Livio; Casasnovas, Olivier; Rusconi, Chiara; Brice, Pauline; Bolis, Silvia; Viviani, Simonetta; Salvi, Flavia; Luminari, Stefano; Hutchings, Martin

    2014-06-01

    A retrospective, international, multicenter study was undertaken to assess: (i) the prognostic role of 'interim' positron emission tomography performed during treatment with doxorubicin, bleomycin, vinblastine and dacarbazine in patients with Hodgkin lymphoma; and (ii) the reproducibility of the Deauville five-point scale for the interpretation of interim positron emission tomography scan. Two hundred and sixty patients with newly diagnosed Hodgkin lymphoma were enrolled. Fifty-three patients with early unfavorable and 207 with advanced-stage disease were treated with doxorubicin, bleomycin, vinblastine and dacarbazine ± involved-field or consolidation radiotherapy. Positron emission tomography scan was performed at baseline and after two cycles of chemotherapy. Treatment was not changed according to the results of the interim scan. An international panel of six expert reviewers independently reported the scans using the Deauville five-point scale, blinded to treatment outcome. Forty-five scans were scored as positive (17.3%) and 215 (82.7%) as negative. After a median follow up of 37.0 (2-110) months, 252 patients are alive and eight have died. The 3-year progression-free survival rate was 83% for the whole study population, 28% for patients with interim positive scans and 95% for patients with interim negative scans (P<0.0001). The sensitivity, specificity, and negative and positive predictive values of interim positron emission tomography scans for predicting treatment outcome were 0.73, 0.94, 0.94 and 0.73, respectively. Binary concordance amongst reviewers was good (Cohen's kappa 0.69-0.84). In conclusion, the prognostic role and validity of the Deauville five-point scale for interpretation of interim positron emission tomography scans have been confirmed by the present study. PMID:24658820

  2. A Gaussian mixture model for definition of lung tumor volumes in positron emission tomography

    SciTech Connect

    Aristophanous, Michalis; Penney, Bill C.; Martel, Mary K.; Pelizzari, Charles A.

    2007-11-15

    The increased interest in {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in radiation treatment planning in the past five years necessitated the independent and accurate segmentation of gross tumor volume (GTV) from FDG-PET scans. In some studies the radiation oncologist contours the GTV based on a computed tomography scan, while incorporating pertinent data from the PET images. Alternatively, a simple threshold, typically 40% of the maximum intensity, has been employed to differentiate tumor from normal tissue, while other researchers have developed algorithms to aid the PET based GTV definition. None of these methods, however, results in reliable PET tumor segmentation that can be used for more sophisticated treatment plans. For this reason, we developed a Gaussian mixture model (GMM) based segmentation technique on selected PET tumor regions from non-small cell lung cancer patients. The purpose of this study was to investigate the feasibility of using a GMM-based tumor volume definition in a robust, reliable and reproducible way. A GMM relies on the idea that any distribution, in our case a distribution of image intensities, can be expressed as a mixture of Gaussian densities representing different classes. According to our implementation, each class belongs to one of three regions in the image; the background (B), the uncertain (U) and the target (T), and from these regions we can obtain the tumor volume. User interaction in the implementation is required, but is limited to the initialization of the model parameters and the selection of an 'analysis region' to which the modeling is restricted. The segmentation was developed on three and tested on another four clinical cases to ensure robustness against differences observed in the clinic. It also compared favorably with thresholding at 40% of the maximum intensity and a threshold determination function based on tumor to background image intensities proposed in a recent paper. The parts of

  3. Clinical Utility of Positron Emission Tomography Magnetic Resonance Imaging (PET-MRI) in Gastrointestinal Cancers.

    PubMed

    Matthews, Robert; Choi, Minsig

    2016-01-01

    Anatomic imaging utilizing both CT (computed tomography) and MRI (magnetic resonance imaging) limits the assessment of cancer metastases in lymph nodes and distant organs while functional imaging like PET (positron emission tomography) scan has its limitation in spatial resolution capacity. Hybrid imaging utilizing PET-CT and PET-MRI are novel imaging modalities that are changing the current landscape in cancer diagnosis, staging, and treatment response. MRI has shown to have higher sensitivity in soft tissue, head and neck pathology, and pelvic disease, as well as, detecting small metastases in the liver and bone compared to CT. Combining MRI with PET allows for detection of metastases that may have been missed with current imaging modalities. In this review, we will examine the clinical utility of FDG PET-MRI in the diagnosis and staging of gastrointestinal cancers with focus on esophageal, stomach, colorectal, and pancreatic cancers. We will also explore its role in treatment response and future directions associated with it.

  4. 18F-FDG positron emission tomography in oncology: main indications.

    PubMed

    Vercher-Conejero, J L; Gámez Cenzano, C

    2016-01-01

    The development of molecular and functional imaging with new imaging techniques such as computed tomography, magnetic resonance imaging, and positron emission tomography (PET) among others, has greatly improved the detection of tumors, tumor staging, and the detection of possible recurrences. Furthermore, the combination of these different imaging modalities and the continual development of radiotracers for PET have advanced our understanding and knowledge of the different pathophysiological processes in cancer, thereby helping to make treatment more efficacious, improving patients' quality of life, and increasing survival. PET is one of the imaging techniques that has attracted the most interest in recent years for its diagnostic capabilities. Its ability to anatomically locate pathologic foci of metabolic activity has revolutionized the detection and staging of many tumors, exponentially broadening its potential indications not only in oncology but also in other fields such as cardiology, neurology, and inflammatory and infectious diseases. PMID:27184919

  5. 18F-FDG positron emission tomography in oncology: main indications.

    PubMed

    Vercher-Conejero, J L; Gámez Cenzano, C

    2016-01-01

    The development of molecular and functional imaging with new imaging techniques such as computed tomography, magnetic resonance imaging, and positron emission tomography (PET) among others, has greatly improved the detection of tumors, tumor staging, and the detection of possible recurrences. Furthermore, the combination of these different imaging modalities and the continual development of radiotracers for PET have advanced our understanding and knowledge of the different pathophysiological processes in cancer, thereby helping to make treatment more efficacious, improving patients' quality of life, and increasing survival. PET is one of the imaging techniques that has attracted the most interest in recent years for its diagnostic capabilities. Its ability to anatomically locate pathologic foci of metabolic activity has revolutionized the detection and staging of many tumors, exponentially broadening its potential indications not only in oncology but also in other fields such as cardiology, neurology, and inflammatory and infectious diseases.

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

    SciTech Connect

    Leenders, K.L.; Frackowiak, R.S.; Quinn, N.; Marsden, C.D.

    1986-01-01

    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-( YF)-fluorodopa uptake was normal, but dopamine (D2) receptor binding was decreased when compared to normal subjects.

  7. Single-photon emission computed tomography in human immunodeficiency virus encephalopathy: A preliminary report

    SciTech Connect

    Masdeu, J.C.; Yudd, A.; Van Heertum, R.L.; Grundman, M.; Hriso, E.; O'Connell, R.A.; Luck, D.; Camli, U.; King, L.N. )

    1991-08-01

    Depression or psychosis in a previously asymptomatic individual infected with the human immunodeficiency virus (HIV) may be psychogenic, related to brain involvement by the HIV or both. Although prognosis and treatment differ depending on etiology, computed tomography (CT) and magnetic resonance imaging (MRI) are usually unrevealing in early HIV encephalopathy and therefore cannot differentiate it from psychogenic conditions. Thirty of 32 patients (94%) with HIV encephalopathy had single-photon emission computed tomography (SPECT) findings that differed from the findings in 15 patients with non-HIV psychoses and 6 controls. SPECT showed multifocal cortical and subcortical areas of hypoperfusion. In 4 cases, cognitive improvement after 6-8 weeks of zidovudine (AZT) therapy was reflected in amelioration of SPECT findings. CT remained unchanged. SPECT may be a useful technique for the evaluation of HIV encephalopathy.