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Sample records for emission tomography studies

  1. 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

  2. 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

  3. Positron emission tomography studies in parkinsonism.

    PubMed

    Eidelberg, D

    1992-05-01

    PET imaging is a rapidly expanding technique with growing clinical utility. In this review, we have discussed the contribution of functional neuroimaging with PET in elucidating the pathophysiology of parkinsonism. In addition, we emphasize the growing role of this technique in the clinical setting. FDG/PET has become increasingly available at major medical centers and is especially suitable as an aid in the clinical assessment of patients with akinetic-rigid or other movement disorders. Although this technique is essentially quantitative and ideally suited for broad population studies, qualitative and semiquantitative approaches may suffice in the evaluation of individual patients. To the extent that several of the functional imaging models are linear with raw count rates, blood sampling may not be needed in each instance. Moreover recent advances in SPECT perfusion imaging may permit the extension of PET diagnostic criteria to other imaging modalities that are less costly and more accessible in the community setting. New statistical methods for the detection of regional metabolic covariation patterns hold special promise for the development of disease-specific imaging markers, which may permit rapid differential diagnosis, improved drug trials, and possible preclinical detection. F-dopa/PET has provided many important in vivo insights into the nigrostriatal dopamine system and its role in the development of parkinsonism. In contrast to FDG/PET, this technique demands specialized radiochemistry, plasma analysis, and modeling approaches that currently restrict its applicability to a few research PET centers. Several promising developments in radiochemical synthesis, data acquisition, and kinetic modeling may simplify the technique sufficiently to be used in the clinical domain. F-dopa/PET holds particular promise in preclinical screening of individuals at risk for Parkinson's disease on genetic or environmental grounds. This has great significance in view of the

  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. Cerebral blood flow and personality: a positron emission tomography study.

    PubMed

    Johnson, D L; Wiebe, J S; Gold, S M; Andreasen, N C; Hichwa, R D; Watkins, G L; Boles Ponto, L L

    1999-02-01

    This study sought to describe brain regions associated with the personality dimension of introversion/extraversion. Measures of cerebral blood flow (CBF) were obtained from 18 healthy subjects by means of [150]H20 positron emission tomography. Correlations of regional CBF with introversion/extraversion were calculated, and a three-dimensional map of those correlations was generated. Overall, introversion was associated with increased blood flow in the frontal lobes and in the anterior thalamus. Regions in the anterior cingulate gyrus, the temporal lobes, and the posterior thalamus were found to be correlated with extraversion. The findings of the study lend support to the notion that introversion is associated with increased activity in frontal lobe regions. Moreover, the study suggests that individual differences in introversion and extraversion are related to differences in a fronto-striato-thalamic circuit.

  6. Translational neuroimaging: positron emission tomography studies of monoamine oxidase.

    PubMed

    Fowler, Joanna S; Logan, Jean; Volkow, Nora D; Wang, Gene-Jack

    2005-01-01

    Positron emission tomography (PET) using radiotracers with high molecular specificity is an important scientific tool in studies of monoamine oxidase (MAO), an important enzyme in the regulation of the neurotransmitters dopamine, norepinephrine, and serotonin as well as the dietary amine, tyramine. MAO occurs in two different subtypes, MAO A and MAO B, which have different substrate and inhibitor specificity and which are different gene products. The highly variable subtype distribution with different species makes human studies of special value. MAO A and B can be imaged in the human brain and certain peripheral organs using PET and carbon-11 (half-life 20.4 minutes) labeled mechanism-based irreversible inhibitors, clorgyline and L -deprenyl, respectively. In this article we introduce MAO and describe the development of these radiotracers and their translation from preclinical studies to the investigation of variables affecting MAO in the human brain and peripheral organs.

  7. Microdosing studies in humans: the role of positron emission tomography.

    PubMed

    Bauer, Martin; Wagner, Claudia Christina; Langer, Oliver

    2008-01-01

    Positron emission tomography (PET)-microdosing comprises the administration of a carbon-11- or fluorine-18-labelled drug candidate to human subjects in order to describe the drug's concentration-time profile in body tissues targeted for treatment. As PET microdosing involves the administration of only microgram amounts of unlabelled drug, the potential toxicological risk to human subjects is very limited. Consequently, regulatory authorities require reduced preclinical safety testing as compared with conventional phase 1 studies. Microdose studies are gaining increasing importance in clinical drug research as they have the potential to shorten time-lines and cut costs along the critical path of drug development. Current applications of PET in anticancer, anti-infective and CNS system drug research are reviewed.

  8. 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.

  9. 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.

  10. SAKE: a new quantification tool for positron emission tomography studies.

    PubMed

    Veronese, Mattia; Rizzo, Gaia; Turkheimer, Federico E; Bertoldo, Alessandra

    2013-07-01

    In dynamic positron emission tomography (PET) studies, spectral analysis (SA) refers to a data-driven quantification method, based on a single-input single-output model for which the transfer function is described by a sum of exponential terms. SA allows to quantify numerosities, amplitudes and eigenvalues of the transfer function allowing, in this way, to separate kinetic components of the tissue tracer activity with minimal model assumptions. The SA model can be solved with a linear estimator alone or with numerical filters, resulting in different types of SA approaches. Once estimated the number, amplitudes and eigenvalues of the transfer function, one can distinguish the presence in the system of irreversible and/or reversible components as well as derive parameters of physiological significance. These characteristics make it an appealing alternative method to compartmental models which are widely used for the quantitative analysis of dynamic studies acquired with PET. However, despite its applicability to a large number of PET tracers, its implementation is not straightforward and its utilization in the nuclear medicine community has been limited especially by the lack of an user-friendly software application. In this paper we proposed SAKE, a computer program for the quantitative analysis of PET data through the main SA methods. SAKE offers a unified pipeline of analysis usable also by people with limited computer knowledge but with high interest in SA. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Positron Emission Tomography - Computed Tomography (PET/CT)

    MedlinePlus

    ... Index A-Z Positron Emission Tomography - Computed Tomography (PET/CT) Positron emission tomography (PET) uses small amounts of ... CT)? What is Positron Emission Tomography – Computed Tomography (PET/CT) Scanning? Positron emission tomography, also called PET imaging ...

  12. Positron emission tomography for use in microdosing studies.

    PubMed

    Wagner, Claudia Christina; Müller, Markus; Lappin, Graham; Langer, Oliver

    2008-01-01

    Positron emission tomography (PET) imaging using microdoses of radiolabeled drug tracers is gaining increasing acceptance in modern clinical drug development. This approach is unique in that it allows for direct quantitative assessment of drug concentrations in the tissues targeted for treatment, thereby bridging the gap between pharmacokinetics and pharmacodynamics. Current applications of PET in anticancer, anti-infective and central nervous system drug research are reviewed herein. Situated at the interface of preclinical and clinical drug testing, PET microdosing is a powerful and highly innovative tool for pharmaceutical development.

  13. Alcohol ADME in Primates Studied with Positron Emission Tomography

    PubMed Central

    Li, Zizhong; Xu, Youwen; Warner, Don; Volkow, Nora D.

    2012-01-01

    Background and Purpose The sensitivity to the intoxicating effects of alcohol as well as its adverse medical consequences differ markedly among individuals, which reflects in part differences in alcohol's absorption, distribution, metabolism, and elimination (ADME) properties. The ADME of alcohol in the body and its relationship with alcohol's brain bioavailability, however, is not well understood. Experimental Approach The ADME of C-11 labeled alcohol, CH311CH2OH, 1 and C-11 and deuterium dual labeled alcohol, CH311CD2OH, 2 in baboons was compared based on the principle that C–D bond is stronger than C–H bond, thus the reaction is slower if C–D bond breaking occurs in a rate-determining metabolic step. The following ADME parameters in peripheral organs and brain were derived from time activity curve (TAC) of positron emission tomography (PET) scans: peak uptake (Cmax); peak uptake time (Tmax), half-life of peak uptake (T1/2), the area under the curve (AUC60min), and the residue uptake (C60min). Key Results For 1 the highest uptake occurred in the kidney whereas for 2 it occurred in the liver. A deuterium isotope effect was observed in the kidneys in both animals studied and in the liver of one animal but not the other. The highest uptake for 1 and 2 in the brain was in striatum and cerebellum but 2 had higher uptake than 1 in all brain regions most evidently in thalamus and cingulate. Alcohol's brain uptake was significantly higher when given intravenously than when given orally and also when the animal was pretreated with a pharmacological dose of alcohol. Conclusion and Implications The study shows that alcohol metabolism in peripheral organs had a large effect on alcohol's brain bioavailability. This study sets the stage for clinical investigation on how genetics, gender and alcohol abuse affect alcohol's ADME and its relationship to intoxication and medical consequences. PMID:23049712

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

    SciTech Connect

    Metter, E.J.; Wasterlain, C.G.; Kuhl, D.E.; Hanson, W.R.; Phelps, M.E.

    1981-08-01

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

  15. 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.

  16. Cardiac positron emission tomography

    SciTech Connect

    Geltman, E.M.

    1985-12-01

    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. 16 references, 9 figures, 2 tables.

  17. Positron emission tomography-computed tomography versus positron emission tomography-magnetic resonance imaging for diagnosis of oral squamous cell carcinoma: A pilot study.

    PubMed

    Schlittenbauer, Tilo; Zeilinger, Martin; Nkenke, Emeka; Kreißel, Sebastian; Wurm, Matthias C; Lell, Michael; Kuwert, Torsten; Beck, Michael

    2015-12-01

    Diagnostic imaging of head and neck cancer has made enormous progress during recent years. Next to morphological imaging modalities (computed tomography [CT] and magnetic resonance imaging [MRI]), there are also hybrid imaging systems that combine functional and morphological information (positron emission tomography [PET]/CT and PET/MRI). The aim of this study was to compare the diagnostic accuracy of PET/MRI in the diagnosis of head and neck cancer with other imaging modalities (MRI, CT, PET/CT). Ten patients (nine male and one female) with histologically proven oral squamous cell carcinoma participated in an 18 F-FDG-PET/CT scan and an additional 18 F-FDG PET/MRI scan prior to surgery. The morphological and functional results were compared with the histological results. Inclusion criteria were histologically proven oral squamous cell carcinoma and no prior surgical intervention, medical therapy, or local external radiation. There was no significant correlation between tumor differentiation and maximum standard uptake values. Functional imaging showed a slightly better correlation with the measurement of the maximal tumor diameter, whereas pure morphological imaging showed a better correlation with the measurement of infiltration depth. Only with PET/MRI could correct lymph node staging be reached; the other imaging tools showed false-negative or false-positive results. In conclusion, we showed in our limited patient cohort that PET/MRI is superior to the morphological imaging modalities, especially for lymph node staging.

  18. Emission tomography of the kidney

    SciTech Connect

    Teates, C.D.; Croft, B.Y.; Brenbridge, N.A.; Bray, S.T.; Williamson, B.R.

    1983-12-01

    Single photon emission computerized tomography (SPECT) was done on two patients with suspected renal masses. Nuclear scintigraphy was equivocal on two tumors readily identified by SPECT. Single photon tomography is cost effective and increases the reliability of nuclear scintigraphy.

  19. 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.

  20. 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.

  1. [Tau Positron Emission Tomography].

    PubMed

    Higuchi, Makoto

    2017-07-01

    Accumulation of fibrillar tau protein aggregates is a neuropathological hallmark of Alzheimer's disease (AD) and related neurodegenerative dementias, including a subgroup of frontotemporal lobar degeneration (FTLD). Visualization of tau lesions in the brains of living subjects enables a pathology-based diagnosis of dementing illnesses in the prodromal stage, and offers objective measures of disease progression and outcomes of disease-modifying therapies. With this rationale, diverse classes of low-molecular-weight chemicals capable of binding to a β-pleated sheet structure have been developed to be used for in vivo positron emission tomography (PET) of tau pathologies. Clinical PET studies of AD patients with such tau probes have provided the following insights: (1) Tau fibrils accumulate in the hippocampal formation in an age-dependent manner that is independent of amyloid-beta peptide (Aβ) pathology; (2) The deposition of Aβ may trigger a spatial expansion of tau pathology, in transition from normal aging to advanced AD; and (3) Tau accumulation is intimately associated with local neuronal loss, leading to cortical atrophy and focal symptoms. In contrast, studies of FTLD have shown a limited performance of first-generation PET probes in capturing non-AD-type tau lesions. New compounds have accordingly been developed and clinically tested, proving to yield a high contrast for tau deposits with high specificity. These second-generation probes are being evaluated primarily by pharmaceutical companies, in line with their growing demands for neuroimaging-based biomarkers serving for clinical trials of anti-Aβ and anti-tau therapies. Meanwhile, a consortium flexibly linking academia and industry to facilitate the utilization of research tools, including tau PET probes, has been established in Japan, for the ultimate purpose of elucidating the molecular etiology of tauopathies and creating diagnostic and therapeutic agents based on such an understanding.

  2. 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.

  3. 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.

  4. Pain and Opiate Receptors: Considerations for the Design of Positron Emission Tomography Studies

    PubMed Central

    Sadzot, B.; Frost, J. J.

    1990-01-01

    Opiate receptors in the brain are the target of endogenous opioids and of exogenous synthetic opiates. These receptors play a major role in the modulation of pain perception. Using the appropriate ligands, positron emission tomography now allows investigators to monitor neuroreceptors in vivo. We have used 11C-diprenorphine and the extremely potent mu opiate receptor agonist, 11C-carfentanil, to image the distribution of opiate receptors in the brain and to quantify their density, their affinity, and their occupancy. Several important aspects of the in vivo opiate receptor labeling with positron emission tomography in relation to the study of pain are considered in this paper. Monitoring receptor occupancy by opiate drugs as a function of pain relief has the potential to reveal better ways to treat pain. PMID:1964768

  5. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography imaging in pyogenic and tuberculous spondylitis: preliminary study.

    PubMed

    Lee, In Sook; Lee, Jung Sub; Kim, Seong-Jang; Jun, Sungmin; Suh, Keun Tak

    2009-01-01

    The purpose of this study was to compare the effectiveness of positron emission tomography (PET)/computed tomography (CT) in distinguishing between tuberculous and pyogenic spondylitis with that of magnetic resonance imaging (MRI). Twenty-two consecutive patients confirmed to have tuberculous or pyogenic spondylitis were examined with both MRI and dual-time point PET/CT. The serum C-reactive protein (CRP) level was measured. The early and delayed PET/CT data were analyzed using the standardized uptake value (SUV). The radiologists scored the MRI findings and differentiated between tuberculous and pyogenic spondylitis. Each MRI result and CRP value was compared with the SUVs of PET/CT. The reviewers identified tuberculous spondylitis (n = 11) on MRI, with a sensitivity, specificity, and positive predictive values of 90%, 100%, and 100%, respectively. For pyogenic spondylitis (n = 11), the corresponding values were 100%, 90%, and 92%, respectively. There was a significant difference in the maximum SUVs of the early phase between tuberculous and pyogenic spondylitis (P = 0.028). Magnetic resonance imaging was superior to PET/CT in differentiating between tuberculous and pyogenic spondylitis (P = 0.043). A comparison of the maximum SUVs of the early phase and CRP values revealed a correlation coefficient of 0.581 (P = 0.006). The maximum SUVs of early-phase PET/CT may be complementary to MRI for differentiating pyogenic and tuberculous spondylitis and reflecting the activity of infectious spondylitis.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Usefulness of Positron Emission Tomography in Patients with Syphilis: A Systematic Review of Observational Studies.

    PubMed

    Chen, Jian-Hua; Zheng, Xin; Liu, Xiu-Qin

    2017-05-05

    Diagnosis of syphilis is difficult. Follow-up and therapy evaluation of syphilitic patients are poor. Little is known about positron emission tomography (PET) in syphilis. This review was to systematically review usefulness of PET for diagnosis, disease extent evaluation, follow-up, and treatment response assessment in patients with syphilis. We searched PubMed, EMBASE, SCOPUS, Cochrane Library, Web of Science, ClinicalTrials.gov, and three Chinese databases (SinoMed, Wanfang, and CNKI) for English and Chinese language articles from inception to September 2016. We also collected potentially relevant studies and reviews using a manual search. The search keywords included the combined text and MeSH terms "syphilis" and "positron emission tomography". We included studies that reporting syphilis with a PET scan before and/or after antibiotic treatment. The diagnosis of syphilis was based on serological criteria or dark field microscopy. Outcomes include pre- and post-treatment PET scan, pre- and post-treatment computed tomography, and pre- and post-treatment magnetic resonance imaging. We excluded the articles not published in English or Chinese or not involving humans. Of 258 identified articles, 34 observational studies were included. Thirty-three studies were single-patient case reports and one study was a small case series. All patients were adults. The mean age of patients was 48.3 ± 12.1 years. In primary syphilis, increased fluorodeoxyglucose (FDG) accumulation could be seen at the site of inoculation or in the regional lymph nodes. In secondary syphilis with lung, bone, gastrointestinal involvement, or generalized lymphadenopathy, increased FDG uptake was the most commonly detected changes. In tertiary syphilis, increased glucose metabolic activity, hypometabolic lesions, or normal glucose uptake might be seen on PET. There were five types of PET scans in neurosyphilis. A repeated PET scan after treatment revealed apparent or complete resolution of the

  11. 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.

  12. Regional cerebral glucose metabolism during sevoflurane anaesthesia in healthy subjects studied with positron emission tomography.

    PubMed

    Schlünzen, L; Juul, N; Hansen, K V; Gjedde, A; Cold, G E

    2010-05-01

    The precise mechanism by which sevoflurane exerts its effects in the human brain remains unknown. In the present study, we quantified the effects of sevoflurane on regional cerebral glucose metabolism (rGMR) in the human brain measured with positron emission tomography. Eight volunteers underwent two dynamic 18F-fluorodeoxyglucose positron emission tomography (PET) scans. One scan assessed conscious-baseline metabolism and the other scan assessed metabolism during 1 minimum alveolar concentration (MAC) sevoflurane anaesthesia. Cardiovascular and respiratory parameters were monitored and bispectral index responses were registered. Statistical parametric maps and conventional regions of interest analysis were used to determine rGMR differences. All subjects were unconsciousness at 1.0 MAC sevoflurane. Cardiovascular and respiratory parameters were constant over time. In the awake state, rGMR ranged from 0.24 to 0.35 mumol/g/min in the selected regions. Compared with the conscious state, total GMR decreased 56% in sevoflurane anaesthesia. In white and grey matter, GMR was averaged 42% and 58% of normal, respectively. Sevoflurane reduced the absolute rGMR in all selected areas by 48-71% of the baseline (P< or = 0.01), with the most significant reductions in the lingual gyrus (71%), occipital lobe in general (68%) and thalamus (63%). No increases in rGMR were observed. Sevoflurane caused a global whole-brain metabolic reduction of GMR in all regions of the human brain, with the most marked metabolic suppression in the lingual gyrus, thalamus and occipital lobe.

  13. FDG positron emission tomography/computed tomography studies of Wilms' tumor.

    PubMed

    Moinul Hossain, A K M; Shulkin, Barry L; Gelfand, Michael J; Bashir, Humayun; Daw, Najat C; Sharp, Susan E; Nadel, Helen R; Dome, Jeffrey S

    2010-07-01

    The purpose of this analysis was to evaluate the utility of FDG PET/CT scanning in patients with Wilms' tumors. A total of 58 scans were performed in 27 patients (14 male, 13 female; ages: 1.9-23 years, median: 7 years) with proven Wilms' tumor. Twenty-six patients (56 scans) were studied at the time of suspected relapse, progressive disease, persistent disease, or for monitoring of therapy. In the 27 patients with Wilms' tumor, 34 scans showed areas of abnormal uptake consistent with metabolically active tumors. Of the patients, 8 (24 scans) had pulmonary metastases larger than 10 mm in diameter, 10 (12 scans) had hepatic metastases, 11 (11 scans) had regional nodal involvement, 3 (3 scans) had bone metastases, 1 (1 scan) had chest wall involvement, 2 (2 scans) had pancreatic metastasis, and 5 (5 scans) had abdominal and pelvic soft tissue involvement. Two of eight patients with lung metastases had variable uptakes. Lung lesions 10 mm or smaller were not consistently visualized on PET scans. One patient with a liver metastasis showed no uptake on PET scan after treatment (size decreased from 45 to 15 mm). Most Wilms' tumors concentrate FDG. However, small pulmonary metastases may be better visualized with CT. FDG PET/CT appears useful for defining the extent of involvement and assessing the response to treatment.

  14. Value of 18fluorodeoxyglucose-positron-emission tomography in amyotrophic lateral sclerosis: a prospective study.

    PubMed

    Van Laere, Koen; Vanhee, Annelies; Verschueren, Jolien; De Coster, Liesbeth; Driesen, An; Dupont, Patrick; Robberecht, Wim; Van Damme, Philip

    2014-05-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder primarily affecting the motor system, with extramotor involvement to a variable extent. Biomarkers for early differential diagnosis and prognosis are needed. An autosomal dominant hexanucleotide (GGGGCC) expansion in the noncoding region of the chromosome 9 open reading frame 72 (C9orf72) gene is the most frequent genetic cause of ALS, but its metabolic pattern has not been studied systematically. To evaluate the use of 18fluorodeoxyglucose-positron-emission tomography as a marker of ALS pathology and investigate whether a specific metabolic signature is present in patients with C9orf72 mutations. In total, 81 patients with a suspected diagnosis of ALS at University Hospital Leuven were prospectively investigated. All underwent detailed neurological examination and electrodiagnostic and genetic testing for the major known genetic causes of ALS (C9orf72, SOD1, TARDBP, and FUS). A diagnosis of ALS was made in 70 of 81 patients. Of these, 11 were C9orf72 positive and 59 were C9orf72 negative. In 7 patients, the diagnosis of primary lateral sclerosis was made; 4 patients had progressive muscular atrophy. A screened healthy control population was used for comparison. Positron-emission tomographic data were spatially normalized and analyzed using a predefined volume of interest and a voxel-based analysis (SPM8). Discriminant analysis was done both volume of interest based and voxel based using a support vector machine approach. Compared with control participants, 18fluorodeoxyglucose-positron-emission tomography showed perirolandic and variable prefrontal hypometabolism in most patients. Patients with primary lateral sclerosis showed a similar pattern. Patients with C9orf72-positive ALS had discrete relative hypometabolism in the thalamus and posterior cingulate compared with those with C9orf72-negative ALS. A posteriori-corrected discriminant analysis was able to correctly classify 95% of ALS cases and

  15. Electrical impedance tomography compared to positron emission tomography for the measurement of regional lung ventilation: an experimental study

    PubMed Central

    Richard, JC; Pouzot, C; Gros, A; Tourevieille, C; Lebars, D; Lavenne, F; Frerichs, I; Guérin, C

    2009-01-01

    Introduction Electrical impedance tomography (EIT), which can assess regional lung ventilation at the bedside, has never been compared with positron-emission tomography (PET), a gold-standard to quantify regional ventilation. This experiment systematically compared both techniques in injured and non-injured lungs. Methods The study was performed in six mechanically ventilated female piglets. In normal lungs, tidal volume (VT) was randomly changed to 6, 8, 10 and 15 ml/kg on zero end-expiratory pressure (ZEEP), then, at VT 10 ml/kg, positive end-expiratory pressure (PEEP) was randomly changed to 5, 10 and 15 cmH2O. Afterwards, acute lung injury (ALI) was subsequently created in three animals by injecting 3 ml/kg hydrochloric acid into the trachea. Then at PEEP 5 cmH2O, VT was randomly changed to 8 and 12 ml/kg and PEEP of 10 and 15 cmH2O applied at VT 10 ml/kg. EIT and PET examinations were performed simultaneously. EIT ventilation (VTEIT) and lung volume (VL) were measured in the anterior and posterior area of each lung. On the same regions of interest, ventilation (VPET) and aerated lung volume (VAatten) were determined with PET. Results On ZEEP, VTEIT and VPET significantly correlated for global (VTEIT = VPET - 2E-13, R2 = 0.95, P < 0.001) and regional (VTEIT = 0.81VPET+7.65, R2 = 0.63, P < 0.001) ventilation over both conditions. For ALI condition, corresponding R2 were 0.91 and 0.73 (P < 0.01). Bias was = 0 and limits of agreement were -37.42 and +37.42 ml/min for global ventilation over both conditions. These values were 0.04 and -29.01 and +29.08 ml/min, respectively, for regional ventilation. Significant correlations were also found between VL and VAatten for global (VL = VAatten+1E-12, R2 = 0.93, P < 0.0001) and regional (VL = 0.99VAatten+0.92, R2 = 0.65, P < 0.001) volume. For ALI condition, corresponding R2 were 0.94 (P < 0.001) and 0.54 (P < 0.05). Bias was = 0 and limits of agreement ranged -38.16 and +38.16 ml for global ventilation over both

  16. 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.

  17. Serotonin transporter in attention-deficit hyperactivity disorder--preliminary results from a positron emission tomography study.

    PubMed

    Karlsson, Linnea; Tuominen, Lauri; Huotarinen, Antti; Leppämäki, Sami; Sihvola, Elina; Helin, Semi; Sipilä, Maria; Tani, Pekka; Hirvonen, Jussi; Hietala, Jarmo; Karlsson, Hasse

    2013-05-30

    The serotonin transporter (SERT) in attention-deficit hyperactivity disorder (ADHD) patients has not been explored by earlier positron emission tomography (PET) studies. We measured SERT availability in female ADHD patients (n=8) and healthy controls (n=14) with PET and [11C]MADAM as a tracer. No significant group differences in [11C]MADAM binding potential were noted.

  18. Prediction of pulmonary function after lung lobectomy by subsegments counting, computed tomography, single photon emission computed tomography and computed tomography: a comparative study.

    PubMed

    Yoshimoto, Kentaro; Nomori, Hiroaki; Mori, Takeshi; Kobayashi, Hironori; Ohba, Yasuomi; Shibata, Hidekatsu; Shiraishi, Shinya; Kobayashi, Toshiaki

    2009-03-01

    The aim of the present study was to determine the optimal method of predicting postoperative pulmonary function (PPF) after lung lobectomy. The forced expiratory volume in 1s (FEV(1)) was measured in 37 patients before and after lobectomy, and the following three methods of predicting the PPF were evaluated: (1) the number of functioning subsegments to be resected were counted (subsegments counting [SC]); (2) the volume of the functioning lung was calculated using CT images (quantitative CT); and (3) perfusion scintigraphy was performed using co-registered single photon emission computed tomography and CT imaging (SPECT/CT). The FEV(1) values predicted using these three methods were then compared with the measured postoperative FEV(1), and the correlations and differences were analyzed. While a paired t-test showed the SPECT/CT method to have the smallest difference between the measured and the predicted FEV(1) values (0.05 l, p=0.33), followed by the quantitative CT method (0.07 l, p=0.07), and finally the SC method (0.15 l, p<0.001), the difference between the two values was not significantly different between the quantitative CT and SPECT/CT method (p=0.22). While the SC method is inferior to both the quantitative CT and the SPECT/CT methods for predicting the PPF after lobectomy, the latter two methods are almost equally accurate.

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

    PubMed

    Markowitsch, H J; Tulving, E

    1994-10-25

    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.

  20. Progressive degeneration of the right temporal lobe studied with positron emission tomography.

    PubMed Central

    Tyrrell, P J; Warrington, E K; Frackowiak, R S; Rossor, M N

    1990-01-01

    A 79 year old man with a twelve year progressive history of prosopagnosia and recent naming difficulty, in whom other intellectual skills were preserved, is described. Positron emission tomography (PET) revealed an area of right temporal lobe hypometabolism, with an additional area of less severe hypometabolism at the left temporal pole. This may represent an example of progressive focal cortical degeneration similar to that associated with primary progressive dysphasia, but affecting the right temporal lobe. Images PMID:2292695

  1. Randomized Trial of Neuroprotective Effects of Erythropoietin in Patients Receiving Adjuvant Chemotherapy for Breast Cancer: Positron Emission Tomography and Neuropsychological Study

    DTIC Science & Technology

    2008-09-01

    Effects of Erythropoietin in Patients Receiving Adjuvant Chemotherapy for Breast Cancer : Positron Emission Tomography and Neuropsychological Study...Neuroprotective Effects of Erythropoietin in Patients 5a. CONTRACT NUMBER Receiving Adjuvant Chemotherapy for Breast Cancer : Positron Emission Tomography...11 Introduction In the United States approximately 60-80% of patients diagnosed with breast cancer will receive

  2. A positron emission tomography microdosing study with sertraline in healthy volunteers.

    PubMed

    Shin, Kwang-Hee; Kim, Kyu-Pyo; Lim, Kyoung Soo; Kim, Ji Who; Lee, Yun-Sang; Yang, Bo Yeun; Lee, Jae Sung; Jung, Jae-Min; Yoon, Seo-Hyun; Jang, In-Jin; Yu, Kyung-Sang

    2012-03-01

    This study explored microdosing methods for evaluating the distribution and pharmacokinetics (PK) of a central nervous system (CNS) drug candidate. We used sertraline as a model drug. In this open-label, one-arm, three-period, multiple-dosing study, 10 healthy male volunteers received 6-day administrations of sertraline at doses of 5, 25 or 50 mg/d in three different periods. Before the first dose of Period 1, and 24 h after the last dose of each period, an intravenous bolus of [11C]sertraline was injected for positron emission tomography (PET) scanning. After the sixth dose in each period, serial blood samples were collected at scheduled intervals over 48 h; then serum sertraline concentrations were determined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sertraline was distributed in the brain within 20 min, and it was highly distributed in the putamen, cingulate, and thalamus. Linearity in steady-state Cmax and AUClast were observed in the 5 - 50 mg dose range. The results suggested that microdosing with PET was a useful method for exploring the bloodbrain- barrier penetration and distribution of a candidate CNS drug. This study described a microdosing method that combined PET with LC-MS/MS for determining the brain distribution and PK characteristics of a CNS drug candidate.

  3. [Multi-center study of inter-scanner difference in brain positron emission tomography].

    PubMed

    Oda, Keiichi; Sakata, Muneyuki; Nishio, Tomoyuki; Tsushima, Hiroyuki; Tanizaki, Yasuo; Kato, Seiji; Ochi, Shinji

    2012-01-01

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

  4. The application of positron emission tomography to the study of normal and pathologic emotions.

    PubMed

    Reiman, E M

    1997-01-01

    This report reviews six studies in which positron emission tomography (PET) was used to investigate the neuroanatomic correlates of emotion, anxiety, and anxiety disorders. PET was used to study brain regions that participate in film- and recall-generated discrete emotions (happiness, sadness, and disgust), picture-generated positive and negative emotions, and normal anticipatory anxiety; participate in the predisposition to, elicitation of, and treatment of panic attacks; participate in social phobic anxiety; and participate in specific phobic anxiety. Results of these investigations suggest that thalamic and medial prefrontal regions may participate in aspects of normal emotion unrelated to its type, valence, or stimulus; that modality-specific sensory association areas and anterior temporal lobe regions appear to participate in the evaluation procedure that invests exteroceptive sensory information with emotional significance; that anterior insular regions appear to participate in the evaluation procedure that invests potentially distressing cognitive and interoceptive sensory information with negative emotional significance; and that anterior cingulate, cerebellar vermis, midbrain, and other brain regions appear to participate in the elaboration of normal and pathologic forms of anxiety. As a complement to other research strategies, PET promises to help determine how multiple brain regions and the mental operations to which they are related work in concert to produce emotions and how they conspire to produce emotional disorders.

  5. 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.

  6. Theory of mind and schizophrenia: a positron emission tomography study of medication-free patients.

    PubMed

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

    2008-07-01

    "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. 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. 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. 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.

  7. Study of direct and indirect parametric estimation methods of linear models in dynamic positron emission tomography.

    PubMed

    Tsoumpas, Charalampos; Turkheimer, Federico E; Thielemans, Kris

    2008-04-01

    In dynamic positron emission tomography (PET) studies, the time changing activity of the radiotracer is measured through multiple consecutive frames. Subsequent pixel-by-pixel application of the appropriate kinetic model provides quantitative information in terms of images of the distribution of the physiological parameter of interest. In this context, iterative reconstruction methods may be used to reconstruct for each time frame a static image of appreciable higher quality than the analytical algorithms, especially in low-count cases. Furthermore, if the reconstruction algorithm also models the kinetics of the measured counts, the parametric image is expected to be of even higher quality. In this work, we investigate the methodology to directly reconstruct parametric images in three-dimensional PET when the kinetic model is linear in its parameters (Patlak plot) and compare with indirectly estimated parametric maps, where the radioactivity distribution was estimated by the filtered back projection and ordered subsets expectation maximization algorithms. Both real and simulated data for tracers with irreversible kinetics in brain studies are included. The results demonstrate appreciable smaller standard deviation and mean squared error characteristics for the direct reconstruction. However, some regions may converge slowly. The FBP and ordered subsets expectation maximization (OSEM) indirect estimations have a similar level of bias after matching their resolutions, but OSEM has smaller standard deviation.

  8. 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. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Pareidolia in Parkinson's disease without dementia: A positron emission tomography study.

    PubMed

    Uchiyama, Makoto; Nishio, Yoshiyuki; Yokoi, Kayoko; Hosokai, Yoshiyuki; Takeda, Atsushi; Mori, Etsuro

    2015-06-01

    Pareidolia, which is a particular type of complex visual illusion, has been reported to be a phenomenon analogous to visual hallucinations in patients with dementia with Lewy bodies. However, whether pareidolia is observed in Parkinson's disease (PD) or whether there are common underlying mechanisms of these two types of visual misperceptions remains to be elucidated. A test to evoke pareidolia, the Pareidolia test, was administered to 53 patients with PD without dementia and 24 healthy controls. The regional cerebral metabolic rate of glucose was measured using 18F-fluorodeoxyglucose positron emission tomography in the PD patients. PD patients without dementia produced a greater number of pareidolic illusions compared with the controls. Pareidolia was observed in all of the patients having visual hallucinations as well as a subset of those without visual hallucinations. The number of pareidolic illusions was correlated with hypometabolism in the bilateral temporal, parietal and occipital cortices. The index of visual hallucinations was correlated with hypometabolism in the left parietal cortex. A region associated with both pareidolia and visual hallucinations was found in the left parietal lobe. Our study suggests that PD patients without dementia experience pareidolia more frequently than healthy controls and that posterior cortical dysfunction could be a common neural mechanism of pareidolia and visual hallucinations. Pareidolia could represent subclinical hallucinations or a predisposition to visual hallucinations in Lewy body disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study.

    PubMed

    Stolin, Alexander V; Martone, Peter F; Jaliparthi, Gangadhar; Raylman, Raymond R

    2017-01-01

    Positron emission tomography (PET) scanners designed for imaging of small animals have transformed translational research by reducing the necessity to invasively monitor physiology and disease progression. Virtually all of these scanners are based on the use of pixelated detector modules arranged in rings. This design, while generally successful, has some limitations. Specifically, use of discrete detector modules to construct PET scanners reduces detection sensitivity and can introduce artifacts in reconstructed images, requiring the use of correction methods. To address these challenges, and facilitate measurement of photon depth-of-interaction in the detector, we investigated a small animal PET scanner (called AnnPET) based on a monolithic annulus of scintillator. The scanner was created by placing 12 flat facets around the outer surface of the scintillator to accommodate placement of silicon photomultiplier arrays. Its performance characteristics were explored using Monte Carlo simulations and sections of the NEMA NU4-2008 protocol. Results from this study revealed that AnnPET's reconstructed spatial resolution is predicted to be [Formula: see text] full width at half maximum in the radial, tangential, and axial directions. Peak detection sensitivity is predicted to be 10.1%. Images of simulated phantoms (mini-hot rod and mouse whole body) yielded promising results, indicating the potential of this system for enhancing PET imaging of small animals.

  11. 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

  12. 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.

  13. Brain uptake of iomazenil in cirrhotic patients: a single photon emission tomography study.

    PubMed

    Kapczinski, F; Quevedo, J; Curran, H V; Fleminger, S; Toone, B; Cluckie, A; Lader, M

    1999-01-01

    Brain uptake of 123I-iomazenil was studied in seven cirrhotic patients and eight normal controls using single photon emission computerized tomography. The highest concentration of the ligand was found in the occipital cortex, which corresponds to the brain region with the highest concentration of benzodiazepine receptors. The peak uptake was delayed in patients across all brain regions. The uptake in occipital cortex was higher in low albumin cirrhotics. Patients with low albumin also presented a more delayed peak uptake in occipital cortex and a higher volume of distribution of iomazenil in plasma, compared to patients with normal albumin levels and controls. The changes in brain uptake (delayed peak uptake and increased maximal uptake in occipital cortex) appears to reflect changes in the pharmacokinetics of the ligand, particularly in cirrhotics with low levels of plasma albumin. The curve of brain uptake of the tracer was modelled into a two compartments equation, which seems to provide a practical and reliable method to calculate the slopes of acquisition and decay, time to peak and maximal acquisition.

  14. Positron emission tomography in the detection of occult primary head and neck carcinoma: a retrospective study

    PubMed Central

    2012-01-01

    Background The management of cervical lymph node metastases from an unknown primary tumor remains a controversial subject. Recently, Positron Emission Tomography (PET) has proved useful in the detection of these tumors, even after an unsuccessful conventional diagnostic workup. This study was performed to assess the role of PET in the detection of occult primary head and neck carcinomas. Methods A retrospective analysis of a four year period at a tertiary referral oncology hospital was conducted. Results Of the 49 patients with cervical metastases of carcinoma from an unknown primary, PET detected a primary in 9 patients and gave 5 false positive and 4 false negative results. Detection rate, sensitivity, specificity and accuracy were of 18.4%, 69.2%, 86.1% and 81.6%, respectively. PET was also of substantial benefit in detecting distant metastatic disease and, thus, altered therapeutic strategies in a significant amount of patients. Conclusions Therefore, PET is a valuable tool in the management of patients with occult primary head and neck carcinoma, not only because it provides additional information as to the location of primary tumors, but also due to the fact that it can detect unexpected distant metastases. PMID:22709938

  15. 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

  16. 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.

  17. Comparison of Positron Emission Tomography Quantification Using Magnetic Resonance- and Computed Tomography-Based Attenuation Correction in Physiological Tissues and Lesions: A Whole-Body Positron Emission Tomography/Magnetic Resonance Study in 66 Patients.

    PubMed

    Seith, Ferdinand; Gatidis, Sergios; Schmidt, Holger; Bezrukov, Ilja; la Fougère, Christian; Nikolaou, Konstantin; Pfannenberg, Christina; Schwenzer, Nina

    2016-01-01

    Attenuation correction (AC) in fully integrated positron emission tomography (PET)/magnetic resonance (MR) systems plays a key role for the quantification of tracer uptake. The aim of this prospective study was to assess the accuracy of standardized uptake value (SUV) quantification using MR-based AC in direct comparison with computed tomography (CT)-based AC of the same PET data set on a large patient population. Sixty-six patients (22 female; mean [SD], 61 [11] years) were examined by means of combined PET/CT and PET/MR (11C-choline, 18F-FDG, or 68Ga-DOTATATE) subsequently. Positron emission tomography images from PET/MR examinations were corrected with MR-derived AC based on tissue segmentation (PET(MR)). The same PET data were corrected using CT-based attenuation maps (μ-maps) derived from PET/CT after nonrigid registration of the CT to the MR-based μ-map (PET(MRCT)). Positron emission tomography SUVs were quantified placing regions of interest or volumes of interest in 6 different body regions as well as PET-avid lesions, respectively. The relative differences of quantitative PET values when using MR-based AC versus CT-based AC were varying depending on the organs and body regions assessed. In detail, the mean (SD) relative differences of PET SUVs were as follows: -7.8% (11.5%), blood pool; -3.6% (5.8%), spleen; -4.4% (5.6%)/-4.1% (6.2%), liver; -0.6% (5.0%), muscle; -1.3% (6.3%), fat; -40.0% (18.7%), bone; 1.6% (4.4%), liver lesions; -6.2% (6.8%), bone lesions; and -1.9% (6.2%), soft tissue lesions. In 10 liver lesions, distinct overestimations greater than 5% were found (up to 10%). In addition, overestimations were found in 2 bone lesions and 1 soft tissue lesion adjacent to the lung (up to 28.0%). Results obtained using different PET tracers show that MR-based AC is accurate in most tissue types, with SUV deviations generally of less than 10%. In bone, however, underestimations can be pronounced, potentially leading to inaccurate SUV quantifications. In

  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. (18) F-sodium fluoride positron emission tomography of the equine distal limb: Exploratory study in three horses.

    PubMed

    Spriet, M; Espinosa, P; Kyme, A Z; Phillips, K L; Katzman, S A; Galuppo, L D; Stepanov, P; Beylin, D

    2017-07-14

    Positron emission tomography (PET) is a cross-sectional, functional imaging modality that has recently become available to the horse. The use of (18) F-sodium fluoride ((18) F-NaF), a PET bone tracer, has not previously been reported in this species. To assess the feasibility of (18) F-NaF PET in the equine distal limb and explore possible applications in the horse in comparison with other imaging modalities. Exploratory descriptive study involving three research horses. Horses were placed under general anaesthesia prior to intravenous (i.v.) administration of 1.5 MBq/kg of (18) F-NaF. Positron emission tomography imaging of both front feet and fetlocks was performed using a portable scanner. Computed tomography (CT) of the distal limb was performed under a separate anaesthetic episode. Bone scintigraphy and magnetic resonance imaging (MRI) were subsequently performed under standing sedation. Images obtained from PET and other imaging modalities were independently assessed and the results correlated. Positron emission tomography images were obtained without complication. The radiation exposure rate was similar to equine bone scintigraphy. Positron emission tomography detected focal (18) F-NaF uptake in areas where other imaging modalities did not identify any abnormalities. This included sites of ligamentous attachment, subchondral compact bone plate and the flexor cortex of the navicular bone. (18) F-NaF uptake was identified in some, but not all, osseous fragments and areas of osseous formation, suggesting a distinction between active and inactive lesions. A small number of horses were included and histopathology was not available. (18) F-NaF PET imaging of the equine distal limb provides useful additional information when compared with CT, MRI and scintigraphy and has the potential for both research and clinical applications in the horse. The Summary is available in Chinese - see Supporting information. © 2017 EVJ Ltd.

  20. Optimised Motion Tracking for Positron Emission Tomography Studies of Brain Function in Awake Rats

    PubMed Central

    Kyme, Andre Z.; Zhou, Victor W.; Meikle, Steven R.; Baldock, Clive; Fulton, Roger R.

    2011-01-01

    Positron emission tomography (PET) is a non-invasive molecular imaging technique using positron-emitting radioisotopes to study functional processes within the body. High resolution PET scanners designed for imaging rodents and non-human primates are now commonplace in preclinical research. Brain imaging in this context, with motion compensation, can potentially enhance the usefulness of PET by avoiding confounds due to anaesthetic drugs and enabling freely moving animals to be imaged during normal and evoked behaviours. Due to the frequent and rapid motion exhibited by alert, awake animals, optimal motion correction requires frequently sampled pose information and precise synchronisation of these data with events in the PET coincidence data stream. Motion measurements should also be as accurate as possible to avoid degrading the excellent spatial resolution provided by state-of-the-art scanners. Here we describe and validate methods for optimised motion tracking suited to the correction of motion in awake rats. A hardware based synchronisation approach is used to achieve temporal alignment of tracker and scanner data to within 10 ms. We explored the impact of motion tracker synchronisation error, pose sampling rate, rate of motion, and marker size on motion correction accuracy. With accurate synchronisation (<100 ms error), a sampling rate of >20 Hz, and a small head marker suitable for awake animal studies, excellent motion correction results were obtained in phantom studies with a variety of continuous motion patterns, including realistic rat motion (<5% bias in mean concentration). Feasibility of the approach was also demonstrated in an awake rat study. We conclude that motion tracking parameters needed for effective motion correction in preclinical brain imaging of awake rats are achievable in the laboratory setting. This could broaden the scope of animal experiments currently possible with PET. PMID:21747951

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

    PubMed

    Kyme, Andre Z; Zhou, Victor W; Meikle, Steven R; Baldock, Clive; Fulton, Roger R

    2011-01-01

    Positron emission tomography (PET) is a non-invasive molecular imaging technique using positron-emitting radioisotopes to study functional processes within the body. High resolution PET scanners designed for imaging rodents and non-human primates are now commonplace in preclinical research. Brain imaging in this context, with motion compensation, can potentially enhance the usefulness of PET by avoiding confounds due to anaesthetic drugs and enabling freely moving animals to be imaged during normal and evoked behaviours. Due to the frequent and rapid motion exhibited by alert, awake animals, optimal motion correction requires frequently sampled pose information and precise synchronisation of these data with events in the PET coincidence data stream. Motion measurements should also be as accurate as possible to avoid degrading the excellent spatial resolution provided by state-of-the-art scanners. Here we describe and validate methods for optimised motion tracking suited to the correction of motion in awake rats. A hardware based synchronisation approach is used to achieve temporal alignment of tracker and scanner data to within 10 ms. We explored the impact of motion tracker synchronisation error, pose sampling rate, rate of motion, and marker size on motion correction accuracy. With accurate synchronisation (<100 ms error), a sampling rate of >20 Hz, and a small head marker suitable for awake animal studies, excellent motion correction results were obtained in phantom studies with a variety of continuous motion patterns, including realistic rat motion (<5% bias in mean concentration). Feasibility of the approach was also demonstrated in an awake rat study. We conclude that motion tracking parameters needed for effective motion correction in preclinical brain imaging of awake rats are achievable in the laboratory setting. This could broaden the scope of animal experiments currently possible with PET.

  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. [Study of regional cerebral glucose metabolism, in man, while awake or asleep, by positron emission tomography].

    PubMed

    Franck, G; Salmon, E; Poirrier, R; Sadzot, B; Franco, G

    1987-03-01

    Measurements of regional cerebral glucose uptake by the 18F-fluorodeoxyglucose technique (18FDG) and positron emission tomography (PET) along with polygraph recordings were made serially during relaxed wakefulness and different stages of nocturnal sleep in two right-handed normal volunteers. During stage III-IV sleep, values declined diffusely in both hemispheric regions (-31%), thalamus (-33%), cerebellum (-33%) and brain stem (-25%). During paradoxical sleep regional values increased diffusely compared with slow wave sleep. Compared to wakefulness, regional metabolic values seemed to increase but the results were more variable from one volunteer to the other. These preliminary data indicate important regional alterations in cerebral metabolism between sleep states.

  4. Dopamine D1 receptor availability is related to social behavior: a positron emission tomography study.

    PubMed

    Plavén-Sigray, Pontus; Gustavsson, Petter; Farde, Lars; Borg, Jacqueline; Stenkrona, Per; Nyberg, Lars; Bäckman, Lars; Cervenka, Simon

    2014-11-15

    Dysfunctional interpersonal behavior is thought to underlie a wide spectrum of psychiatric disorders; however, the neurobiological underpinnings of these behavioral disturbances are poorly understood. Previous molecular imaging studies have shown associations between striatal dopamine (DA) D2-receptor binding and interpersonal traits, such as social conformity. The objective of this study was to explore, for the first time, the role of DA D1-receptors (D1-Rs) in human interpersonal behavior. Twenty-three healthy subjects were examined using positron emission tomography and the radioligand [(11)C]SCH23390, yielding D1-R binding potential values. Striatal D1-R binding was related to personality scales selected to specifically assess one dimension of interpersonal behavior, namely a combination of affiliation and dominance (i.e., the Social Desirability, Verbal Trait Aggression and Physical Trait Aggression scales from Swedish Universities Scales of Personality). An exploratory analysis was also performed for extrastriatal brain regions. D1-R binding potential values in the limbic striatum (r = .52; p = .015), associative striatum (r = .55; p = .009), and sensorimotor striatum (r = .67; p = .001) were positively related to Social Desirability scores. D1-R binding potential in the limbic striatum (r = -.51; p = .019) was negatively associated with Physical Trait Aggression scores. For extrastriatal regions, Social Desirability scores showed positive correlations in the amygdala (r = .60; p = .006) and medial frontal cortex (r = .60; p = .004). This study provides further support for the role of DA function in the expression of disaffiliative and dominant traits. Specifically, D1-R availability may serve as a marker for interpersonal behavior in humans. Associations were demonstrated for the same dimension of interpersonal behavior as for D2-R, but in the opposite direction, suggesting that the two receptor subtypes are involved in the same behavioral processes, but

  5. 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.

  6. Charged-particle emission tomography.

    PubMed

    Ding, Yijun; Caucci, Luca; Barrett, Harrison H

    2017-06-01

    Conventional charged-particle imaging techniques - such as autoradiography - provide only two-dimensional (2D) black ex vivo images of thin tissue slices. In order to get volumetric information, images of multiple thin slices are stacked. This process is time consuming and prone to distortions, as registration of 2D images is required. We propose a direct three-dimensional (3D) autoradiography technique, which we call charged-particle emission tomography (CPET). This 3D imaging technique enables imaging of thick tissue sections, thus increasing laboratory throughput and eliminating distortions due to registration. CPET also has the potential to enable in vivo charged-particle imaging with a window chamber or an endoscope. Our approach to charged-particle emission tomography uses particle-processing detectors (PPDs) to estimate attributes of each detected particle. The attributes we estimate include location, direction of propagation, and/or the energy deposited in the detector. Estimated attributes are then fed into a reconstruction algorithm to reconstruct the 3D distribution of charged-particle-emitting radionuclides. Several setups to realize PPDs are designed. Reconstruction algorithms for CPET are developed. Reconstruction results from simulated data showed that a PPD enables CPET if the PPD measures more attributes than just the position from each detected particle. Experiments showed that a two-foil charged-particle detector is able to measure the position and direction of incident alpha particles. We proposed a new volumetric imaging technique for charged-particle-emitting radionuclides, which we have called charged-particle emission tomography (CPET). We also proposed a new class of charged-particle detectors, which we have called particle-processing detectors (PPDs). When a PPD is used to measure the direction and/or energy attributes along with the position attributes, CPET is feasible. © 2017 The Authors. Medical Physics published by Wiley Periodicals

  7. 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

  8. Disclosure of positron emission tomography amyloid imaging results: A preliminary study of safety and tolerability.

    PubMed

    Lim, Yen Ying; Maruff, Paul; Getter, Christine; Snyder, Peter J

    2016-04-01

    Three (18)F-labeled radiopharmaceuticals have been Food and Drug Administration-approved for the identification of cortical amyloidosis in clinical settings. Although there has been strong debate among professionals as to the ethical and social consequences of disclosing such information, increasing numbers of participants are being recruited into secondary prevention trials for which they are likely to, and/or desire to, receive their positron emission tomography (PET) imaging results. Healthy older adults (n = 63, mean age = 62 years) enrolled in a preclinical Alzheimer's disease (AD) biomarkers trial, and 11 requested disclosure of PET amyloid imaging results to their treating neurologist, per institutional review board-approved study protocol. These individuals completed a follow-up psychoeducational program and structured interviews to assess impact of disclosure on several key psychological factors. Four of 11 subjects demonstrated increased amyloid aggregation and reported that they were not surprised, particularly given their family histories and subjective memory concerns. All indicated that they had shared this information with pertinent significant others; they were satisfied with their level of social support, and the imaging results had motivated them to change their lifestyle by exercising more, changing their diet, and planning ahead. Amyloid-positive participants showed little change in levels of depressive, anxiety, and stress symptoms, subjective sense of memory impairment, or on measures of intrusion, avoidance, and hyperarousal, and reported risk of self-harm. Disclosure of PET amyloid status did not significantly impact mood, subjective sense of memory impairment, or perceived risk of developing AD; nor was this associated with significant emotional impact, irrespective of actual amyloid burden status. Those subjects with increased amyloid burden were more likely than those without significant amyloidosis to make positive changes to their

  9. [Neurotransmitter systems in the human brain studied by positron emission tomography].

    PubMed

    Shinotoh, H

    1996-12-01

    Positron emission tomography with appropriate tracers provides unique opportunity to study neurotransmitter systems in the living human brain. PET with [18F] 6-fluoro-L-dopa (FD) provides an index of the integrity of nigrostriatal pathway, and striatal FD uptake correlates linearly with the density of nigral neurons. PET allows us to assess the progression of the nigral lesions in Parkinson's disease (PD). A 68-year-old normal female volunteer was scanned by FD-PET. Subsequently, she developed parkinsonism 3.7 years after the scan. A repeated FD-PET scan revealed a significant reduction of FD uptake by 20% over the 5.2 year interval. The results suggest a relatively short presymptomatic period with fast initial losses of nigral neurons in PD. FD-PET has been used to determine the viability of fetal graft implanted in the striatum for the treatment of PD. PET imaging of dopamine D1 and D2 receptors may be useful for the differential diagnosis of PD and striatonigral degeneration. PET reveals significant reduction of dopamine D1 and D2 receptor binding in the putamen of patients with SND, while D1 and D2 receptor binding is normal or slightly upregulated in PD. We found hypersensitivity of muscarinic cholinergic receptors in the frontal cortex of patients with PD by using PET. The result suggests a loss of ascending cholinergic system in the frontal cortex in PD, which may cause the frontal lobe dysfunction in PD. Recently, acetylcholine analogs labelled with positron emitter have been developed for measurement of brain acetylcholinesterase activity in vivo. These tracers may be useful for the assessment of ascending cholinergic system in Alzheimer's disease and PD.

  10. Glycine Transporter Type 1 Occupancy by Bitopertin: a Positron Emission Tomography Study in Healthy Volunteers

    PubMed Central

    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

    2013-01-01

    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 [11C]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 (VT) values were highest in the pons, thalamus, and cerebellum (1.7–2.7 ml/cm3) and lowest in cortical areas (∼0.8 ml/cm3). VT 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 EC50 of ∼190, ∼200, and ∼130 ng/ml, respectively. Emax 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

  11. Activity-based costing evaluation of a [(18)F]-fludeoxyglucose positron emission tomography study.

    PubMed

    Krug, Bruno; Van Zanten, Annie; Pirson, Anne-Sophie; Crott, Ralph; Borght, Thierry Vander

    2009-10-01

    The aim of the study is to use the activity-based costing approach to give a better insight in the actual cost structure of a positron emission tomography procedure (FDG-PET) by defining the constituting components and by simulating the impact of possible resource or practice changes. The cost data were obtained from the hospital administration, personnel and vendor interviews as well as from structured questionnaires. A process map separates the process in 16 patient- and non-patient-related activities, to which the detailed cost data are related. One-way sensitivity analyses shows to which degree of uncertainty the different parameters affect the individual cost and evaluate the impact of possible resource or practice changes like the acquisition of a hybrid PET/CT device, the patient throughput or the sales price of a 370MBq (18)F-FDG patient dose. The PET centre spends 73% of time in clinical activities and the resting time after injection of the tracer (42%) is the single largest departmental cost element. The tracer cost and the operational time have the most influence on cost per procedure. The analysis shows a total cost per FDG-PET ranging from 859 Euro for a BGO PET camera to 1142 Euro for a 16 slices PET-CT system, with a distribution of the resource costs in decreasing order: materials (44%), equipment (24%), wage (16%), space (6%) and hospital overhead (10%). The cost of FDG-PET is mainly influenced by the cost of the radiopharmaceutical. Therefore, the latter rather than the operational time should be reduced in order to improve its cost-effectiveness.

  12. 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.

  13. Cerebral Hypoperfusion in Hereditary Coproporphyria (HCP): A Single Photon Emission Computed Tomography (SPECT) Study

    PubMed Central

    Valle, Guido; Guida, Claudio Carmine; Nasuto, Michelangelo; Totaro, Manuela; Aucella, Filippo; Frusciante, Vincenzo; Di Mauro, Lazzaro; Potenza, Adele; Savino, Maria; Stanislao, Mario; Popolizio, Teresa; Guglielmi, Giuseppe; Giagulli, Vito Angelo; Guastamacchia, Edoardo; Triggiani, Vincenzo

    2016-01-01

    Background: Hereditary Coproporphyria (HCP) is characterized by abdominal pain, neurologic symptoms and psychiatric disorders, even if it might remain asymptomatic. The pathophysiology of both neurologic and psychiatric symptoms is not fully understood. Therefore, aiming to evaluate a possible role of brain blood flow disorders, we have retrospectively investigated cerebral perfusion patterns in Single Photon Emission Computed Tomography (SPECT) studies in HCP patients. Materials & Methods: We retrospectively evaluated the medical records of patients diagnosed as being affected by HCP. A total of seven HCP patients had been submitted to brain perfusion SPECT study with 99mTc-Exametazime (hexamethylpropyleneamine oxime, HMPAO) or with its functionally equivalent 99mTc-Bicisate (ECD or Neurolite) according with common procedures. In 3 patients the scintigraphic study had been repeated for a second time after the first evaluation at 3, 10 and 20 months, respectively. All the studied subjects had been also submitted to an electromyographic and a Magnetic Resonance Imaging (MRI) study of the brain. Results: Mild to moderate perfusion defects were detected in temporal lobes (all 7 patients), frontal lobes (6 patients) and parietal lobes (4 patients). Occipital lobe, basal ganglia and cerebellar involvement were never observed. In the three subjects in which SPECT study was repeated, some recovery of hypo-perfused areas and appearance of new perfusion defects in other brain regions have been found. In all patients electromyography resulted normal and MRI detected few unspecific gliotic lesions only in one patient. Discussion & Conclusions: Since perfusion abnormalities were usually mild to moderate, this can probably explain the normal pattern observed at MRI studies. Compared to MRI, SPECT with 99mTc showed higher sensitivity in HCP patients. Changes observed in HCP patients who had more than one study suggest that transient perfusion defects might be due to a brain

  14. Cerebral Hypoperfusion in Hereditary Coproporphyria (HCP): A Single Photon Emission Computed Tomography (SPECT) Study.

    PubMed

    Valle, Guido; Guida, Claudio Carmine; Nasuto, Michelangelo; Totaro, Manuela; Aucella, Filippo; Frusciante, Vincenzo; Di Mauro, Lazzaro; Potenza, Adele; Savino, Maria; Stanislao, Mario; Popolizio, Teresa; Guglielmi, Giuseppe; Giagulli, Vito Angelo; Guastamacchia, Edoardo; Triggiani, Vincenzo

    2016-01-01

    Hereditary Coproporphyria (HCP) is characterized by abdominal pain, neurologic symptoms and psychiatric disorders, even if it might remain asymptomatic. The pathophysiology of both neurologic and psychiatric symptoms is not fully understood. Therefore, aiming to evaluate a possible role of brain blood flow disorders, we have retrospectively investigated cerebral perfusion patterns in Single Photon Emission Computed Tomography (SPECT) studies in HCP patients. We retrospectively evaluated the medical records of patients diagnosed as being affected by HCP. A total of seven HCP patients had been submitted to brain perfusion SPECT study with 99mTc-Exametazime (hexamethylpropyleneamine oxime, HMPAO) or with its functionally equivalent 99mTc-Bicisate (ECD or Neurolite) according with common procedures. In 3 patients the scintigraphic study had been repeated for a second time after the first evaluation at 3, 10 and 20 months, respectively. All the studied subjects had been also submitted to an electromyographic and a Magnetic Resonance Imaging (MRI) study of the brain. Mild to moderate perfusion defects were detected in temporal lobes (all 7 patients), frontal lobes (6 patients) and parietal lobes (4 patients). Occipital lobe, basal ganglia and cerebellar involvement were never observed. In the three subjects in which SPECT study was repeated, some recovery of hypo-perfused areas and appearance of new perfusion defects in other brain regions have been found. In all patients electromyography resulted normal and MRI detected few unspecific gliotic lesions only in one patient. Discussion & Conclusions: Since perfusion abnormalities were usually mild to moderate, this can probably explain the normal pattern observed at MRI studies. Compared to MRI, SPECT with 99mTc showed higher sensitivity in HCP patients. Changes observed in HCP patients who had more than one study suggest that transient perfusion defects might be due to a brain artery spasm possibly leading to psychiatric

  15. 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

  16. Central representation of phantom limb phenomenon in amputees studied with single photon emission computerized tomography.

    PubMed

    Liaw, M Y; You, D L; Cheng, P T; Kao, P F; Wong, A M

    1998-01-01

    To explore the possible mechanisms of phantom limb discomfort after amputation, three amputees with phantom limb pain were studied. This study examined the change of regional cerebral blood flow using technetium-99m hexamethylpropyleneamine oxime-single photon emission computerized tomography, which was arranged at the time of severe phantom limb discomfort and after the discomfort subsided or was completely relieved. Nine representative transverse slices parallel to the orbitomeatal line were selected for quantification. The cortical ribbon (2-cm thickness) was equally subdivided into 12 symmetrical pairs of sector regions of interest in each slice. The irregularly shaped regions of interest were drawn manually around the right thalamus and basal ganglion and then mirrored to the left thalamus and basal ganglion. The contralateral to ipsilateral ratio of regional cerebral blood flow for each area was calculated. The intensity of phantom limb pain was evaluated on a 0 to 10 visual analog scale. In Cases 1 and 2, the contralateral to ipsilateral regional cerebral blood flow ratios of multiple areas of the frontal, temporal, or parietal lobes were increased at the time of more severe phantom limb pain, and the ratios were normalized or even decreased when the phantom limb pain subsided. In Case 3, increased contralateral to ipsilateral regional cerebral blood flow ratios were also found over the frontal, temporal, and parietal lobe. However, most of the increased regional cerebral blood flow ratios of regions of interest in the first study persisted in the follow-up study. Also, the regional cerebral blood flow ratios of greater number of regions of interest of the same gyrus and new gyrus were increased. There was no significant right-left difference of regional cerebral blood flow over bilateral thalami and basal ganglia in all three cases. The results suggested that phantom limb pain might be associated with cortical activation involving the frontal, temporal, or

  17. Exenatide improves both hepatic and adipose tissue insulin resistance: A dynamic positron emission tomography study.

    PubMed

    Gastaldelli, Amalia; Gaggini, Melania; Daniele, Giuseppe; Ciociaro, Demetrio; Cersosimo, Eugenio; Tripathy, Devjit; Triplitt, Curtis; Fox, Peter; Musi, Nicolas; DeFronzo, Ralph; Iozzo, Patricia

    2016-12-01

    Glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1-RAs) act on multiple tissues, in addition to the pancreas. Recent studies suggest that GLP-1-RAs act on liver and adipose tissue to reduce insulin resistance (IR). Thus, we evaluated the acute effects of exenatide (EX) on hepatic (Hep-IR) and adipose (Adipo-IR) insulin resistance and glucose uptake. Fifteen male subjects (age = 56 ± 8 years; body mass index = 29 ± 1 kg/m(2) ; A1c = 5.7 ± 0.1%) were studied on two occasions, with a double-blind subcutaneous injection of EX (5 μg) or placebo (PLC) 30 minutes before a 75-g oral glucose tolerance test (OGTT). During OGTT, we measured hepatic (HGU) and adipose tissue (ATGU) glucose uptake with [(18) F]2-fluoro-2-deoxy-D-glucose/positron emission tomography, lipolysis (RaGly) with [U-(2) H5 ]-glycerol, oral glucose absorption (RaO) with [U-(13) C6 ]-glucose, and hepatic glucose production (EGP) with [6,6-(2) H2 ]-glucose. Adipo-IR and Hep-IR were calculated as (FFA0-120min ) × (Ins0-120min ) and (EGP0-120min ) × (Ins0-120min ), respectively. EX reduced RaO, resulting in reduced plasma glucose and insulin concentration from 0 to 120 minutes postglucose ingestion. EX decreased Hep-IR (197 ± 28 to 130 ± 37; P = 0.02) and increased HGU of orally administered glucose (23 ± 4 to 232 ± 89 [μmol/min/L]/[μmol/min/kg]; P = 0.003) despite lower insulin (23 ± 5 vs. 41 ± 5 mU/L; P < 0.02). EX enhanced insulin suppression of RaGly by decreasing Adipo-IR (23 ± 4 to 13 ± 3; P = 0.009). No significant effect of insulin was observed on ATGU (EX = 1.16 ± 0.15 vs. PLC = 1.36 ± 0.13 [μmol/min/L]/[μmol/min/kg]). Acute EX administration (1) improves Hep-IR, decreases EGP, and enhances HGU and (2) reduces Adipo-IR, improves the antilipolytic effect of insulin, and reduces plasma free fatty acid levels during OGTT. (Hepatology 2016;64:2028-2037). © 2016 by the American Association for the Study of Liver Diseases.

  18. Effect of gender on glucose utilization rates in healthy humans: A positron emission tomography study

    SciTech Connect

    Miura, S.A.; Schapiro, M.B.; Grady, C.L.; Kumar, A.; Salerno, J.A.; Kozachuk, W.E.; Wagner, E.; Rapoport, S.I.; Horwitz, B. )

    1990-12-01

    Positron emission tomography (PET) was used with 18fluorodeoxyglucose to see if gender differences in resting cerebral glucose utilization could be detected. Thirty-two healthy subjects (15 women and 17 men; age range: 21-38 yr) were examined using a high-resolution PET scanner to determine the regional cerebral metabolic rate for glucose (CMRglc) in 65 gray matter regions of interest. Whole brain CMRglc did not differ significantly between the two genders, nor did any of the regional CMRglc values. Only 1 of 65 ratios of regional-to-whole brain CMRglc differed significantly between men and women, which is consistent with chance. These results indicate that there are no differences in resting regional cerebral glucose utilization between young men and women.

  19. 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.

  20. Synthesis and positron emission tomography studies of carbon-11-labeled imatinib (Gleevec)

    PubMed Central

    Kil, Kun-Eek; Ding, Yu-Shin; Lin, Kuo-Shyan; Alexoff, David; Kim, Sung Won; Shea, Colleen; Xu, Youwen; Muench, Lisa; Fowler, Joanna S.

    2010-01-01

    Introduction Imatinib mesylate (Gleevec) is a well known drug for treating chronic myeloid leukemia and gastrointestinal stromal tumors. Its active ingredient, imatinib ([4-[(4-methyl-1-piperazinyl)methyl]-N-[4-methyl-3-[[4-(3-pyridyl)-2-pyrimidinyl]amino]phenyl]benzamide), blocks the activity of several tyrosine kinases. Here we labeled imatinib with carbon-11 as a tool for determining the drug distribution and pharmacokinetics of imatinib, and we carried out positron emission tomography (PET) studies in baboons. Methods [N-11C-methyl]imatinib was synthesized from [11C]methyl iodide and norimatinib was synthesized by the demethylation of imatinib (isolated from Gleevec tablets) according to a patent procedure [Collins JM, Klecker RW Jr, Anderson LW. Imaging of drug accumulation as a guide to antitumor therapy. US Patent 20030198594A1, 2003]. Norimatinib was also synthesized from the corresponding amine and acid. PET studies were carried out in three baboons to measure pharmacokinetics in the brain and peripheral organs and to determine the effect of a therapeutic dose of imatinib. Log D and plasma protein binding were also measured. Results [N-11C-methyl]imatinib uptake in the brain is negligible (consistent with P-glycoprotein-mediated efflux); it peaks and clears rapidly from the heart, lungs and spleen. Peak uptake and clearance occur more slowly in the liver and kidneys, followed by accumulation in the gallbladder and urinary bladder. Pretreatment with imatinib did not change uptake in the heart, lungs, kidneys and spleen, and increased uptake in the liver and gallbladder. Conclusions [N-11C-methyl]imatinib has potential for assessing the regional distribution and kinetics of imatinib in the human body to determine whether the drug targets tumors and to identify other organs to which the drug or its labeled metabolites distribute. Paired with tracers such as 2-deoxy-2-[18F]fluoro-D-glucose (18FDG) and 3′-deoxy-3′-[18F]fluorothymidine (18FLT), [N-11C

  1. Kinetic modeling of 5-fluorouracil anabolism in colorectal adenocarcinoma: a positron emission tomography study in rats.

    PubMed

    Bading, James R; Yoo, Paul B; Fissekis, John D; Alauddin, Mian M; D'Argenio, David Z; Conti, Peter S

    2003-07-01

    Drug uptake and anabolism by tumors are prerequisites of response to 5-fluorouracil (5-FU). Positron emission tomography (PET) with 5-[(18)F]FU (PET/5-[(18)F]FU) is potentially useful for noninvasive measurement of these processes, but is severely hampered by rapid catabolism of 5-[(18)F]FU in vivo. This study explored the combined use of PET/5-[(18)F]FU and eniluracil (5-ethynyluracil), a potent inhibitor of 5-FU catabolism, to measure the pharmacokinetics of 5-FU uptake and metabolism in tumors. Rats bearing a s.c. implanted rat colon tumor were given eniluracil and injected i.v. with 5-[(18)F]FU. Dynamic PET and arterial blood sampling were performed 0-2 h. Tumors (n = 5) were then rapidly excised, frozen, and analyzed for labeled metabolites by high performance liquid chromatography. Tumor TACs were analyzed by compartmental modeling. Compartments were identified with molecular species by comparison with ex vivo assays. Tumor extracellular fluid volume was determined in a separate group of rats. Kinetic analysis indicated partial trapping of (18)F within tumors 0-2 h after injection. Tumor time-activity curves conformed closely to a catenary 3-compartment, 5-parameter model. The model yielded values for 5-FU clearance from plasma into the trap that agreed closely with those reported previously for gastrointestinal tumors from a PET/5-[(18)F]FU + eniluracil study in humans. Tumor extracellular fluid volume as measured with (99m)Tc DTPA [(3.1 +/- 0.2) x 10(-1) ml/g; n = 5] agreed well with the distribution volume for compartment 1 of the 3-compartment, 5-parameter model [(3.7 +/- 0.3) x 10(-1) ml/g; n = 5], thus indicating that compartment 1 corresponds to tumor extracellular space. Compartment 3 closely matched the combined magnitudes of (18)F fluoronucleoside (FN) triphosphates and macromolecules in all of the cases, and compartment 2 was quantitatively consistent with the sum of intracellular 5-FU, FNs, and FN mono- and diphosphates. These observations show

  2. 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.

  3. 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.

  4. Positron emission tomography/computed tomography in melanoma.

    PubMed

    Bourgeois, Austin C; Chang, Ted T; Fish, Lindsay M; Bradley, Yong C

    2013-09-01

    Fludeoxyglucose F 18 positron emission tomography/computed tomography (PET/CT) has been invaluable in the assessment of melanoma throughout the course of the disease. As with any modality, the studies are incomplete and more information will be gleaned as our experience progresses. Additionally, it is hoped that a newer PET agent in the pipeline will give us even greater success in the identification and subsequent treatment of melanoma. This article aims to examine the utilization of PET/CT in the staging, prognostication, and follow-up of melanoma while providing the physicians who order and interpret these studies practical guidelines and interpretive pitfalls. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Serotonin Synthesis and Reuptake in Social Anxiety Disorder: A Positron Emission Tomography Study.

    PubMed

    Frick, Andreas; Åhs, Fredrik; Engman, Jonas; Jonasson, My; Alaie, Iman; Björkstrand, Johannes; Frans, Örjan; Faria, Vanda; Linnman, Clas; Appel, Lieuwe; Wahlstedt, Kurt; Lubberink, Mark; Fredrikson, Mats; Furmark, Tomas

    2015-08-01

    Serotonin is involved in negative affect, but whether anxiety syndromes, such as social anxiety disorder (SAD), are characterized by an overactive or underactive serotonin system has not been established. Serotonin 1A autoreceptors, which inhibit serotonin synthesis and release, are downregulated in SAD, and serotonin transporter availability might be increased; however, presynaptic serotonin activity has not been evaluated extensively. To examine the serotonin synthesis rate and serotonin transporter availability in patients with SAD and healthy control individuals using positron emission tomography (PET) with the radioligands 5-hydroxytryptophan labeled with carbon 11 ([11C]5-HTP) and 11C-labeled 3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile [11C]DASB. We performed a cross-sectional study at an academic clinical research center. Eighteen patients with SAD (9 men and 9 women; mean [SD] age, 32.6 [8.2] years) and 18 sex- and age-matched healthy controls (9 men and 9 women; mean [SD] age, 34.7 [9.2] years) underwent [11C]5-HTP PET imaging. We acquired [11C]DASB PET images for 26 additional patients with SAD (14 men and 12 women; mean [SD] age, 35.2 [10.7] years) and the same 18 sex- and age-matched healthy controls. Participants were recruited through newspaper advertisements. Data were acquired from March 12, 2002, through March 5, 2012, and analyzed from March 28, 2013, through August 29, 2014. The influx rate of [11C]5-HTP as a measure of serotonin synthesis rate capacity and [11C]DASB binding potential as an index of serotonin transporter availability were acquired during rest. We used the Liebowitz Social Anxiety Scale to measure severity of social anxiety symptoms. The PET data were not available for analysis in 1 control for each scan. Increased [11C]5-HTP influx rate was observed in the amygdala, raphe nuclei region, caudate nucleus, putamen, hippocampus, and anterior cingulate cortex of patients with SAD compared with healthy controls (P

  6. A wavelet phase filter for emission tomography

    SciTech Connect

    Olsen, E.T.; Lin, B.

    1995-07-01

    The presence of a high level of noise is a characteristic in some tomographic imaging techniques such as positron emission tomography (PET). Wavelet methods can smooth out noise while preserving significant features of images. Mallat et al. proposed a wavelet based denoising scheme exploiting wavelet modulus maxima, but the scheme is sensitive to noise. In this study, the authors explore the properties of wavelet phase, with a focus on reconstruction of emission tomography images. Specifically, they show that the wavelet phase of regular Poisson noise under a Haar-type wavelet transform converges in distribution to a random variable uniformly distributed on [0, 2{pi}). They then propose three wavelet-phase-based denoising schemes which exploit this property: edge tracking, local phase variance thresholding, and scale phase variation thresholding. Some numerical results are also presented. The numerical experiments indicate that wavelet phase techniques show promise for wavelet based denoising methods.

  7. 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

  8. 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

  9. 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

  10. Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study.

    PubMed

    Van de Kelft, Erik; Verleye, Gino; Van de Kelft, An-Sofie; Melis, Koen; Van Goethem, Johan

    2017-10-01

    The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP. To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II). A prospective comparative study. Two hundred patients were enrolled: 96 in Group I and 104 in Group II. Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records. Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest. The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this

  11. Where the imaginal appears real: A positron emission tomography study of auditory hallucinations

    PubMed Central

    Szechtman, Henry; Woody, Erik; Bowers, Kenneth S.; Nahmias, Claude

    1998-01-01

    An auditory hallucination shares with imaginal hearing the property of being self-generated and with real hearing the experience of the stimulus being an external one. To investigate where in the brain an auditory event is “tagged” as originating from the external world, we used positron emission tomography to identify neural sites activated by both real hearing and hallucinations but not by imaginal hearing. Regional cerebral blood flow was measured during hearing, imagining, and hallucinating in eight healthy, highly hypnotizable male subjects prescreened for their ability to hallucinate under hypnosis (hallucinators). Control subjects were six highly hypnotizable male volunteers who lacked the ability to hallucinate under hypnosis (nonhallucinators). A region in the right anterior cingulate (Brodmann area 32) was activated in the group of hallucinators when they heard an auditory stimulus and when they hallucinated hearing it but not when they merely imagined hearing it. The same experimental conditions did not yield this activation in the group of nonhallucinators. Inappropriate activation of the right anterior cingulate may lead self-generated thoughts to be experienced as external, producing spontaneous auditory hallucinations. PMID:9465124

  12. Second order components of moving plaids activate extrastriate cortex: a positron emission tomography study.

    PubMed

    Wenderoth, P; Watson, J D; Egan, G F; Tochon-Danguy, H J; O'keefe, G J

    1999-02-01

    A moving plaid is a composite pattern produced by superimposing two sinusoidal gratings which differ in orientation and motion direction. The perceived drift direction of a plaid appears to be determined partly by a binocular mechanism, which follows intersection of constraint rules (Burke and Wenderoth, 1993b), and partly by a monocular mechanism, which tracks the dark and bright intersects of the plaid, the contrast envelopes. The first neurones that respond to plaids as patterns rather than component gratings are found in area V5, also known as MT, which is exclusively binocular. Therefore, the psychophysical evidence suggesting that the contrast envelope tracking mechanism is monocular is surprising but has been obtained consistently. We aimed to localize the contrast envelope tracking mechanism by undertaking a positron emission tomography (PET) activation experiment in which the subjects were presented with alternating plaid components during the control scan and with the moving plaid resulting from the superposition of these components as the activation scan. The results showed differential activation in area V3. Recent results from macaque single cell recordings have also demonstrated increased sensitivity to moving plaid stimuli compared to the plaid component gratings in V3 neurones. Copyright 1999 Academic Press.

  13. 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.

  14. 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.

  15. A study of persistent post-concussion symptoms in mild head trauma using positron emission tomography

    PubMed Central

    Chen, S; Kareken, D; Fastenau, P; Trexler, L; Hutchins, G

    2003-01-01

    Background: Complaints of persistent cognitive deficits following mild head trauma are often uncorroborated by structural brain imaging and neuropsychological examination. Objective: To investigate, using positron emission tomography (PET), the in vivo changes in regional cerebral uptake of 2-[18F]fluoro-2-deoxy-D-glucose (FDG) and regional cerebral blood flow (rCBF) in patients with persistent symptoms following mild head trauma. Methods: Five patients with mild head trauma and five age and education matched healthy controls were imaged using FDG-PET to measure differences in resting regional cerebral glucose metabolism. Oxygen-15 labelled water (H215O)-PET was also used to measure group differences in rCBF changes during a spatial working memory task. In addition, neuropsychological testing and self report of dysexecutive function and post-concussion symptoms were acquired to characterise the sample. Results: There was no difference between patients and controls in normalised regional cerebral FDG uptake in the resting state in frontal and temporal regions selected a priori. However, during the spatial working memory task, patients had a smaller increase in rCBF than controls in the right prefrontal cortex. Conclusions: Persistent post-concussive symptoms may not be associated with resting state hypometabolism. A cognitive challenge may be necessary to detect cerebral changes associated with mild head trauma. PMID:12588917

  16. 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

  17. [Visualized study on acupuncture treatment of children autism using single photon emission computed tomography].

    PubMed

    Jia, Shao-Wei; Sun, Tao-Tao; Fan, Rong

    2008-10-01

    To provide the molecular iconographic evidence for acupuncture treatment of children autism (CA). Electric acupuncture (EA) was applied on acupoints of bilateral Hegu (LI4), Quchi (LI11), Zusanli (ST36) and Sanyinjiao (SP6) in 34 CA patients' with ABC scale > 57 scores. Using SIEMENS ECAM / ICON double head system, single photon emission computed tomography (SPECT) brain perfusion imaging were performed before and during EA with 99mTc-ECD. Then SPECT images were analyzed visually and quantitatively. Visual analysis showed that 114 foci of low cerebral perfusion and function were found in 34 CA patients before EA, 28 cases (82.35%) of them with abnormalities in left (or both) front lobes, left Broca area and left Wernicke area. During EA, the affected areas improved to different extent. Quantitative analysis showed that significant difference existed between pre-EA focal Ff and mirror-side Ff, pre-EA Ff and mid-EA Fe, focal BFCR% and mirror-side BFCR % (all P < 0.01). The improving analysis of cerebral perfusion and function showed that the efficacy of EA was 78.95%. Acupuncture was proved preliminarily effective in treating children autism.

  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. Development of novel emission tomography system

    NASA Astrophysics Data System (ADS)

    Fu, Geng

    In recent years, small animals, such as mice and rats, have been widely used as subjects of study in biomedical research while molecular biology and imaging techniques open new opportunities to investigate disease model. With the help of medical imaging techniques, researchers can investigate underlying mechanisms inside the small animal, which are useful for both early diagnosis and treatment monitoring. Based on tracer principle single photon emission computed tomography (SPECT) has increased popularity in small animal imaging due to its higher spatial resolution and variety of single-photon emitting radionuclides. Since the image quality strongly depends on the detector properties, both scintillation and semiconductor detectors are under active investigation for high resolution X-ray and gamma ray photon detection. The desired detector properties include high intrinsic spatial resolution, high energy resolution, and high detection efficiency. In this thesis study, we have made extensive efforts to develop novel emission tomography system, and evaluate the use of both semiconductor and ultra-high resolution scintillation detectors for small animal imaging. This thesis work includes the following three areas. Firstly, we have developed a novel energy-resolved photon counting (ERPC) detector. With the benefits of high energy resolution, high spatial resolution, flexible detection area, and a wide dynamic range of 27--200keV, ERPC detector is well-suited for small animal SPECT applications. For prototype ERPC detector excellent imaging (˜350microm) and spectroscopic performance (4keV Co-57 122keV) has been demonstrated in preliminary study. Secondly, to further improve spatial resolution to hundred-micron level, an ultra-high resolution Intensified EMCCD (I-EMCCD) detector has been designed and evaluated. This detector consists of the newly developed electron multiplying CCD (EMCCD) sensor, columnar CsI(Tl) scintillator, and an electrostatic de-magnifier (DM) tube

  20. A method for comparing intra-tumoural radioactivity uptake heterogeneity in preclinical positron emission tomography studies.

    PubMed

    Grafström, Jonas; Ahlzén, Hanna-Stina; Stone-Elander, Sharon

    2015-12-01

    Non-uniformity influences the interpretation of nuclear medicine based images and consequently their use in treatment planning and monitoring. However, no standardised method for evaluating and ranking heterogeneity exists. Here, we have developed a general algorithm that provides a ranking and a visualisation of the heterogeneity in small animal positron emission tomography (PET) images. The code of the algorithm was written using the Matrix Laboratory software (MATLAB). Parameters known to influence the heterogeneity (distances between deviating peaks, gradients and size compensations) were incorporated into the algorithm. All data matrices were mathematically constructed in the same format with the aim of maintaining overview and control. Histograms visualising the spread and frequency of contributions to the heterogeneity were also generated. The construction of the algorithm was tested using mathematically generated matrices and by varying post-processing parameters. It was subsequently applied in comparisons of radiotracer uptake in preclinical images in human head and neck carcinoma and endothelial and ovarian carcinoma xenografts. Using the developed algorithm, entire tissue volumes could be assessed and gradients could be handled in an indirect manner. Similar-sized volumes could be compared without modifying the algorithm. Analyses of the distribution of different tracers gave results that were generally in accordance with single plane preclinical images, indicating that it could appropriately handle comparisons of targeting vs. non-targeting tracers and also for different target levels. Altering the reconstruction algorithm, pixel size, tumour ROI volumes and lower cut-off limits affected the calculated heterogeneity factors in expected directions but did not reverse conclusions about which tumour was more or less heterogeneous. The algorithm constructed is an objective and potentially user-friendly tool for one-to-one comparisons of heterogeneity in

  1. 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.

  2. 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

  3. 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)

  4. 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)

  5. Method for Studying the Myocardial Blood Flow Reserve by Load Dynamic Single-Photon Emission Computed Tomography.

    PubMed

    Mochula, A V; Zavadovsky, K V; Lishmanov, Yu B

    2016-04-01

    We developed a method for collection and processing of scintigraphic data to estimate myocardial reserve in a gamma-chamber with cadmium-zinc-telluride detectors. Dynamic single-photon emission computed tomography of the heart with (99m)Tc-Technetril was performed in 16 coronary heart disease patients at rest and during pharmacological load. During data processing, regions of interest from the cavity and the myocardium of the left ventricle were formed and activity-time curves were constructed. The index of myocardial blood fl ow reserve was calculated as the difference between two ratios of the mean gamma-count from the myocardial area to the area under the left ventricle cavity curve (peak) during load and at rest. The mean indices of myocardial reserve in healthy volunteers and patients with coronary artery atherosclerosis were 1.86 (1.59; 2.20) and 1.39 (1.12; 1.69), respectively. The development of the method for studying myocardial reserve by single-photon emission computed tomography is an urgent problem and requires further investigations.

  6. Prospective Study of 68Ga-DOTATATE Positron Emission Tomography/Computed Tomography for Detecting Gastro-Entero-Pancreatic Neuroendocrine Tumors and Unknown Primary Sites

    PubMed Central

    Sadowski, Samira M.; Neychev, Vladimir; Millo, Corina; Shih, Joanna; Nilubol, Naris; Herscovitch, Peter; Pacak, Karel; Marx, Stephen J.

    2016-01-01

    Purpose Gastro-entero-pancreatic neuroendocrine tumors (GEPNETs) are increasing in incidence, and accurate staging is important for selecting the appropriate treatment. 68Ga-DOTATATE imaging is a promising approach for detecting GEPNETs and could help in selecting optimal therapeutic strategies. The aim of this study was to prospectively determine the clinical utility of 68Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) in detecting unknown primary and metastatic GEPNETs. Patients and Methods One hundred thirty-one patients were enrolled in a prospective study of patients undergoing 68Ga-DOTATATE PET/CT, 111In-pentetreotide single-photon emission computed tomography (SPECT)/CT and multiphasic CT scan, and/or magnetic resonance imaging in a blinded fashion with comprehensive biochemical testing. The primary outcome measure was the detection of lesions by each imaging study. Results 68Ga-DOTATATE PET/CT imaging detected 95.1% of lesions (95% CI, 92.4% to 96.8%) with an average maximum standardized uptake value of 65.4 ± 47 (range, 6.9 to 244), anatomic imaging detected 45.3% of lesions (95% CI, 37.9% to 52.9%), and 111In-pentetreotide SPECT/CT detected 30.9% of lesions (95% CI, 25.0% to 37.5%), with a significant difference between imaging modalities (P < .001). In four of 14 patients (28.6%), 68Ga-DOTATATE PET/CT found a previously unknown primary tumor, and detected primary GEPNET, lymph node, and distant metastases correctly in 72 of 113 lesions (63.7%) when compared with histopathology, with 22.1% and 38.9% detected by using 111In-pentetreotide SPECT/CT and anatomic imaging, respectively. On the basis of findings with 68Ga-DOTATATE PET/CT, 43 of 131 patients (32.8%) had a change in management recommendation. In patients with carcinoid symptoms but negative biochemical testing, 68Ga-DOTATATE PET/CT detected lesions in 65.2% of patients, 40% of which were detected neither by anatomic imaging nor by 111In-pentetreotide SPECT/CT. Conclusion

  7. The neurobiology of glucocerebrosidase-associated parkinsonism: a positron emission tomography study of dopamine synthesis and regional cerebral blood flow.

    PubMed

    Goker-Alpan, Ozlem; Masdeu, Joseph C; Kohn, Philip D; Ianni, Angela; Lopez, Grisel; Groden, Catherine; Chapman, Molly C; Cropp, Brett; Eisenberg, Daniel P; Maniwang, Emerson D; Davis, Joie; Wiggs, Edythe; Sidransky, Ellen; Berman, Karen F

    2012-08-01

    Mutations in GBA, the gene encoding glucocerebrosidase, the enzyme deficient in Gaucher disease, are common risk factors for Parkinson disease, as patients with Parkinson disease are over five times more likely to carry GBA mutations than healthy controls. Patients with GBA mutations generally have an earlier onset of Parkinson disease and more cognitive impairment than those without GBA mutations. We investigated whether GBA mutations alter the neurobiology of Parkinson disease, studying brain dopamine synthesis and resting regional cerebral blood flow in 107 subjects (38 women, 69 men). We measured dopamine synthesis with (18)F-fluorodopa positron emission tomography, and resting regional cerebral blood flow with H(2)(15)O positron emission tomography in the wakeful, resting state in four study groups: (i) patients with Parkinson disease and Gaucher disease (n = 7, average age = 56.6 ± 9.2 years); (ii) patients with Parkinson disease without GBA mutations (n = 11, 62.1 ± 7.1 years); (iii) patients with Gaucher disease without parkinsonism, but with a family history of Parkinson disease (n = 14, 52.6 ± 12.4 years); and (iv) healthy GBA-mutation carriers with a family history of Parkinson disease (n = 7, 50.1 ± 18 years). We compared each study group with a matched control group. Data were analysed with region of interest and voxel-based methods. Disease duration and Parkinson disease functional and staging scores were similar in the two groups with parkinsonism, as was striatal dopamine synthesis: both had greatest loss in the caudal striatum (putamen Ki loss: 44 and 42%, respectively), with less reduction in the caudate (20 and 18% loss). However, the group with both Parkinson and Gaucher diseases showed decreased resting regional cerebral blood flow in the lateral parieto-occipital association cortex and precuneus bilaterally. Furthermore, two subjects with Gaucher disease without parkinsonian manifestations showed diminished striatal dopamine. In conclusion

  8. Patient Study of In Vivo Verification of Beam Delivery and Range, Using Positron Emission Tomography and Computed Tomography Imaging After Proton Therapy

    SciTech Connect

    Parodi, Katia . E-mail: Katia.Parodi@med.uni-heidelberg.de; Paganetti, Harald; Shih, Helen A.; Michaud, Susan; Loeffler, Jay S.; DeLaney, Thomas F.; Liebsch, Norbert J.; Munzenrider, John E.; Fischman, Alan J.; Knopf, Antje; Bortfeld, Thomas

    2007-07-01

    Purpose: To investigate the feasibility and value of positron emission tomography and computed tomography (PET/CT) for treatment verification after proton radiotherapy. Methods and Materials: This study included 9 patients with tumors in the cranial base, spine, orbit, and eye. Total doses of 1.8-3 GyE and 10 GyE (for an ocular melanoma) per fraction were delivered in 1 or 2 fields. Imaging was performed with a commercial PET/CT scanner for 30 min, starting within 20 min after treatment. The same treatment immobilization device was used during imaging for all but 2 patients. Measured PET/CT images were coregistered to the planning CT and compared with the corresponding PET expectation, obtained from CT-based Monte Carlo calculations complemented by functional information. For the ocular case, treatment position was approximately replicated, and spatial correlation was deduced from reference clips visible in both the planning radiographs and imaging CT. Here, the expected PET image was obtained from an analytical model. Results: Good spatial correlation and quantitative agreement within 30% were found between the measured and expected activity. For head-and-neck patients, the beam range could be verified with an accuracy of 1-2 mm in well-coregistered bony structures. Low spine and eye sites indicated the need for better fixation and coregistration methods. An analysis of activity decay revealed as tissue-effective half-lives of 800-1,150 s. Conclusions: This study demonstrates the feasibility of postradiation PET/CT for in vivo treatment verification. It also indicates some technological and methodological improvements needed for optimal clinical application.

  9. Can Positron Emission Tomography/Computed Tomography with the Dual Tracers Fluorine-18 Fluoroestradiol and Fluorodeoxyglucose Predict Neoadjuvant Chemotherapy Response of Breast Cancer? ----A Pilot Study

    PubMed Central

    Yang, Zhongyi; Sun, Yifei; Xue, Jing; Yao, Zhifeng; Xu, Junyan; Cheng, Jingyi; Shi, Wei; Zhu, Beiling; Zhang, Yongping; Zhang, Yingjian

    2013-01-01

    Objective To assess the clinical value of dual tracers Positron emission tomography/computed tomography (PET/CT) 18F-fluoroestradiol (18F-FES) and 18F-fluorodeoxyglucose (18F-FDG) in predicting neoadjuvant chemotherapy response (NAC) of breast cancer. Methods Eighteen consecutive patients with newly diagnosed, non-inflammatory, stage II and III breast cancer undergoing NAC were included. Before chemotherapy, they underwent both 18F-FES and 18F-FDG PET/CT scans. Surgery was performed after three to six cycles of chemotherapy. Tumor response was graded and divided into two groups: the responders and non-responders. We used the maximum standardized uptake value (SUVmax) to qualify each primary lesion. Results Pathologic analysis revealed 10 patients were responders while the other 8 patients were non-responders. There was no statistical difference of SUVmax-FDG and tumor size between these two groups (P>0.05). On the contrary, SUVmax-FES was lower in responders (1.75±0.66 versus 4.42±1.14; U=5, P=0.002); and SUVmax-FES/FDG also showed great value in predicting outcome (0.16±0.06 versus 0.54±0.22; U=5, P=0.002). Conclusions Our study showed 18F-FES PET/CT might be feasible to predict response of NAC. However, whether the use of dual tracers 18F-FES and 18F-FDG has complementary value should be further studied. PMID:24205151

  10. In Vivo Tissue Pharmacokinetics of Carbon-11-Labeled Clozapine in Healthy Volunteers: A Positron Emission Tomography Study

    PubMed Central

    Park, HS; Kim, E; Moon, BS; Lim, NH; Lee, BC; Kim, SE

    2015-01-01

    We investigated clozapine (CLZ) tissue pharmacokinetics in vivo by using carbon-11-labeled CLZ (11C-CLZ) and positron emission tomography (PET). Eight healthy volunteers underwent 11C-CLZ studies wherein computed tomography image acquisition was followed by PET scans (whole-body, four; brain, four). After bolus intravenous 11C-CLZ injection, PET images were acquired at various timepoints for 2–3 hours. Tissue 11C-CLZ signals were plotted over time, and pharmacokinetic parameters were determined. High 11C-CLZ radioactivity was detected in the liver and brain, implying CLZ hepatic metabolism and efficient blood–brain barrier penetration. The urinary and hepatobiliary tracts were involved in 11C-CLZ excretion. Moderate to high radioactivity was observed in the dopaminergic and serotonergic receptor-rich brain regions, indicating CLZ binding to multiple receptor types. To our knowledge, this is the first study to report the determination of 11C-CLZ tissue pharmacokinetics in humans. PET using radiolabeled drugs can provide valuable information that could complement plasma pharmacokinetic data. PMID:26225256

  11. The influence of tomograph sensitivity on kinetic parameter estimation in positron emission tomography imaging studies of the rat brain.

    PubMed

    Meikle, S R; Eberl, S; Fulton, R R; Kassiou, M; Fulham, M J

    2000-08-01

    We investigated the influence of tomograph sensitivity on reliability of parameter estimation in positron emission tomography studies of the rat brain. The kinetics of two tracers in rat striatum and cerebellum were simulated. A typical injected dose of 10 MBq and a reduced dose of 1 MBq were assumed. Kinetic parameters were estimated using a region of interest (ROI) analysis and two pixel-by-pixel analyses. Striatal binding potential was estimated as a function of effective tomograph sensitivity (S(eff)) using a simplified reference tissue model. A S(eff) value of > or =1% was required to ensure reliable parameter estimation for ROI analysis and a S(eff) of 3-6% was required for pixel-by-pixel analysis. We conclude that effective tomograph sensitivity of 3% may be an appropriate design goal for rat brain imaging.

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

    SciTech Connect

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

    1985-05-01

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

  13. Role and interpretation of fluorodeoxyglucose-positron emission tomography/computed tomography in HIV-infected patients with fever of unknown origin: a prospective study.

    PubMed

    Martin, C; Castaigne, C; Tondeur, M; Flamen, P; De Wit, S

    2013-09-01

    The aim of the study was to evaluate prospectively the usefulness of fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in investigation of fever of unknown origin (FUO) in HIV-positive patients and to determine whether HIV viraemia impacts on FDG-PET/CT performance. The FDG-PET/CT results of 20 HIV-infected patients with FUO were analysed and compared with the FDG-PET/CT results of 10 HIV-infected viraemic patients without FUO. The performance of FDG-PET/CT for identifying the aetiology of FUO was assessed. Final diagnosis for FUO was based on histopathology, microbiological assays, or clinical and imaging follow-up. FDG-PET/CT contributed to the diagnosis or exclusion of a focal aetiology of the febrile state in 80% of patients with FUO. The presence of increased FDG uptake in the central lymph node has 100% specificity for focal aetiology of fever, even in viraemic patients. The absence of hypermetabolic central lymph nodes in FUO patients has 100% negative predictive value for focal disease. Lymph node biopsy in central hypermetabolic areas allowed, in 100% of cases, identification of underlying disease in patients with FUO. Biopsy of peripheral lymph nodes should be performed in lymph nodes with maximum standardized uptake value (SUVmax) ≥ 6-8 (sensitivity 62.5%; specificity 75%) and avoided in lymph nodes with SUVmax = 0-4 (specificity 0%). High HIV viraemia does not prevent correct interpretation of FDG-PET/CT. As in HIV-negative patients, we confirm the usefulness of FDG-PET/CT in investigation of FUO in HIV-positive patients even if they are viraemic. © 2013 British HIV Association.

  14. Application of the Intraoperative Dual Photon Emission Computed Tomography System in Sentinel Lymph Node Detection: A Simulation Study

    NASA Astrophysics Data System (ADS)

    Lin, Chang-Shiun; Lin, Hsin-Hon.; Ni, Yu-Ching; Jan, Meei-Ling.; Lu, Kuan-Pai; Chuang, Keh-Shih

    2016-02-01

    The sentinel lymph node (SLN) hypothesis is applied as part of the standard procedure for identifying early-stage breast cancer. Thus, an imaging system that can locate SLNs in operating rooms is desired. Many 2-D probe imaging systems and a freehand single-photon emission-computed tomography (fhSPECT) system have been proposed. However, 2-D probe imaging systems are affected by shine-through and shadowing effects. Here, we propose an alternative to 3-D imaging systems, i.e., a dual-photon emission computed tomography (DuPECT) system, which integrates both preoperative and intraoperative information to locate SLNs using cascade isotopes such as Se-75. The system consists of a LaBr3-based probe and planar head, a collimation system, and a coincidence circuit. For each disintegration, the slat and parallel-hole collimator define a plane and a line, respectively, which represent the possible flight paths of each photon. SLNs can be located using the line-plane intersection. Here, the performance is evaluated using Monte Carlo software developed in our laboratory, integrated with SimSET and GATE software. A measurement study indicates that the randoms rate increases with increased initial activities, while the scatter rate is lower than 1.2 count/s for various activities. In a simulated imaging study, four injection sites and two LNs placed at various depths are minimally distinguishable. However, the LNs are clearly identifiable in the absence of injection sites. Our results indicate that the proposed three-dimensional imaging system has the potential to identify injection sites and various SLNs. However, difficulties with low sensitivity for LN detection, especially in the presence of activity from injection sites, and the choice of appropriate radioisotope must be overcome for its clinical usage.

  15. 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.

  16. Positron emission tomography/computerized tomography for tumor response assessment-a review of clinical practices and radiomics studies.

    PubMed

    Lu, Wei; Chen, Wengen

    2016-08-01

    Even with recent advances in cancer diagnosis and therapy, treatment outcomes for many cancers remain dismal. Patients often show different response to the same therapy regimen, supporting the development of personalized medicine. 18F-FDG PET/CT has been used routinely in the assessment of tumor response, in prediction of outcomes, and in guiding personalized treatment. These assessments are mainly based on physician's subjective or semi-quantitative evaluation. Recent development in Radiomics provides a promising objective way for tumor response assessment, which uses computerized tools to extract a large number of image features that capture additional information not currently used in clinic that has prognostic value. In this review, we summarized the clinical use of PET/CT and the PET/CT Radiomics studies for tumor response assessment. Finally, we discussed some challenges and future perspectives.

  17. Positron emission tomography/computerized tomography for tumor response assessment—a review of clinical practices and radiomics studies

    PubMed Central

    Lu, Wei; Chen, Wengen

    2016-01-01

    Even with recent advances in cancer diagnosis and therapy, treatment outcomes for many cancers remain dismal. Patients often show different response to the same therapy regimen, supporting the development of personalized medicine. 18F-FDG PET/CT has been used routinely in the assessment of tumor response, in prediction of outcomes, and in guiding personalized treatment. These assessments are mainly based on physician’s subjective or semi-quantitative evaluation. Recent development in Radiomics provides a promising objective way for tumor response assessment, which uses computerized tools to extract a large number of image features that capture additional information not currently used in clinic that has prognostic value. In this review, we summarized the clinical use of PET/CT and the PET/CT Radiomics studies for tumor response assessment. Finally, we discussed some challenges and future perspectives. PMID:27904837

  18. Pilot study of F(18)-Fluorodeoxyglucose Positron Emission Tomography/computerised tomography in Wilms' tumour: correlation with conventional imaging, pathology and immunohistochemistry.

    PubMed

    Begent, Joanna; Sebire, Neil J; Levitt, Gill; Brock, Penelope; Jones, Kathy Pritchard; Ell, Peter; Gordon, Isky; Anderson, John

    2011-02-01

    Wilms' tumour is the second most common paediatric solid tumour. Prognosis is good although higher stage disease carries significant mortality and treatment related morbidity. In the UK, risk stratification is based on histological response to pre-operative chemotherapy. F(18)-Fluorodeoxyglucose Positron Emission Tomography (F(18)FDG-PET) is an emerging functional imaging technique in paediatric oncology. Little is known about the relationship between F(18)FDG-PET images and the disease process of Wilms' tumour. We performed F(18)FDG-PET/CT scans in seven children with Wilms' tumour after induction chemotherapy, immediately before surgery. The standard uptake values (SUV) of F(18)FDG-PET/CT images were related to conventional imaging and histopathological findings. In total seven children were studied. F(18)FDG-PET/CT was consistently safely performed. All tumours showed F(18)FDG activity. Four tumours had activity with SUV/bw max >5 g/ml. Histological examination of these active areas revealed viable anaplastic Wilms' tumour. Furthermore, in these four tumours GLUT-1 and Ki67 immunostaining was strongly positive. Three further tumours demonstrated lower uptake (SUV/bw max <5 g/ml), which represented areas of microscopic foci of residual viable tumour mixed with post chemotherapy change. Metastatic disease was F(18)FDG avid in two of four children with stage four diseases. In conclusion, following chemotherapy, active Wilms' tumour is F(18)FDG avid and higher SUV was seen in histologically high risk disease.

  19. 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).

  20. 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).

  1. 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.

  2. 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

  3. Quantitative positron emission tomography in brain research.

    PubMed

    Heurling, Kerstin; Leuzy, Antoine; Jonasson, My; Frick, Andreas; Zimmer, Eduardo R; Nordberg, Agneta; Lubberink, Mark

    2017-09-01

    The application of positron emission tomography (PET) in brain research has increased substantially during the past 20years, and is still growing. PET provides a unique insight into physiological and pathological processes in vivo. In this article we introduce the fundamentals of PET, and the methods available for acquiring quantitative estimates of the parameters of interest. A short introduction to different areas of application is also given, including basic research of brain function and in neurology, psychiatry, drug receptor occupancy studies, and its application in diagnostics of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Our aim is to inform the unfamiliar reader of the underlying basics and potential applications of PET, hoping to inspire the reader into considering how the technique could be of benefit for his or her own research. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. 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.

  5. Advanced instrumentation for Positron Emission Tomography

    SciTech Connect

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

    1985-04-01

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

  6. 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

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

    2016-08-28

    To clarify clinicopathological features of ductal carcinoma in situ (DCIS) visualized on [F-18] fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT). 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. [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. 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.

  7. Vitamin D Status and Coronary Flow Reserve Measured by Positron Emission Tomography: A Co-Twin Control Study

    PubMed Central

    Karohl, Cristina; Vaccarino, Viola; Veledar, Emir; Goldberg, Jack; Tangpricha, Vin; Bellasi, Antonio

    2013-01-01

    Context: Vitamin D insufficiency is associated with increased cardiovascular events in the general population. Additionally, low serum 25-hydroxyvitamin D [25(OH)D] is associated with endothelial dysfunction and arterial stiffness. However, little is known about the association between serum 25(OH)D level and myocardial blood flow. Objective: Our objective was to examine the association between serum 25(OH)D levels and coronary flow reserve (CFR) measured by 13N-positron emission tomography in asymptomatic middle-aged male twins. Design: The Emory Twin Study is a cross-sectional study of soldiers from the Vietnam Era Registry. Setting: The study was conducted at the General Clinical Research Center, Emory University, Atlanta, GA. Participants: A total of 368 middle-aged male twins were enrolled for the study. Serum 25(OH)D levels were measured in all subjects and classified as vitamin D insufficiency [25(OH)D <30 ng/ml] or sufficiency [25(OH)D ≥30 ng/ml]. Positron emission tomography with [13N]ammonia was used to evaluate myocardial blood flow at rest and after adenosine stress. CFR was measured as the ratio of maximum to rest myocardial blood flow. Main Outcome Measure: Primary outcome was CFR measurement. Results: Mean overall serum 25(OH)D concentration was 37.0 ± 21.4 ng/ml; 167 twins (45%) were vitamin D insufficient. CFR was significantly lower in subjects with vitamin D insufficiency compared with subjects with vitamin D sufficiency (2.41 vs. 2.64; P = 0.007), even after adjustment for traditional cardiovascular risk factors, serum PTH, calcium, and phosphorus levels, and season. An abnormal CFR (CFR <2) was more prevalent in subjects with vitamin D insufficiency than with vitamin D sufficiency (31 vs. 20%; P = 0.03). In addition, in vitamin D status-discordant twin pairs, CFR was significantly lower in the vitamin D-insufficient twin than in the vitamin D-sufficient co-twin (2.35 vs. 2.58; P = 0.037). Conclusion: Vitamin D insufficiency is associated

  8. Possible effects of tetrahydrobiopterin treatment in six children with autism--clinical and positron emission tomography data: a pilot study.

    PubMed

    Fernell, E; Watanabe, Y; Adolfsson, I; Tani, Y; Bergström, M; Hartvig, P; Lilja, A; von Knorring, A L; Gillberg, C; Långström, B

    1997-05-01

    Six children, between 3 and 5 years of age, having infantile autism according to DSM-III-R, were treated for 3 months with 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (R-BH4), a cofactor for tyrosine hydroxylases in the biosynthetic pathway of catecholamines and serotonin. A criterion for inclusion in the study was a relatively low level of R-BH4 in the cerebrospinal fluid. For clinical evaluation, the Parental Satisfaction Survey (PASS) was used every fourth week and the Griffiths Developmental Scales were used before starting and 3 months after completing the treatment. During the treatment period, all parents reported improvements in the child's social functioning-mainly eye contact and desire to interact-and in the number of words or sounds which the child used. Small positive changes were noted on the Griffiths Developmental Scales between the two testing occasions. R-BH4 levels in CSF increased significantly after treatment. The positron emission tomography (PET) study showed that the high value of dopamine D2 receptor binding in the caudate and putamen decreased by about 10% towards the normal level after treatment with R-BH4. The observations in this open study indicate that the drug might be useful for a subgroup of children with autism, but there is a need for a larger double-blind study with a longer treatment period.

  9. The leptomeningeal ivy sign on fluid-attenuated inversion recovery images in moyamoya disease: positron emission tomography study.

    PubMed

    Kaku, Yasuyuki; Iihara, Koji; Nakajima, Norio; Kataoka, Hiroharu; Fukushima, Kazuhito; Iida, Hidehiro; Hashimoto, Nobuo

    2013-01-01

    The ivy sign is sometimes seen on fluid-attenuated inversion recovery (FLAIR) images in moyamoya disease (MMD). In recent studies using single-photon emission computed tomography, ivy sign proliferation correlated with decreases in cerebrovascular reserve. However, a decreased vascular reserve is not concrete. The purpose of this study was to evaluate the correlation between ivy sign proliferation and the findings of 15O gas positron emission tomography (PET). In 19 MMD patients (12 women, age 31-69 years) with ischemic symptoms, FLAIR magnetic resonance imaging and 15O gas PET were performed. We classified the middle cerebral artery (MCA) territory into 2 regions in each hemisphere, and the degree of the ivy sign (ivy sign score) in each region was classified into 3 grades (0-2), where grade 0 indicated an absence of the ivy sign, grade 1 indicated that the ivy sign was seen on less than half of the cortical surface in each region, and grade 2 indicated that the ivy sign was seen on more than half of the cortical surface. We examined the relationship among the ivy sign score, the severity of ischemic symptoms and PET parameters in 76 MCA regions of 19 patients. Ivy sign scores of the regions were 0 (n = 19), 1 (n = 40), and 2 (n = 17). Total ivy sign score of a hemisphere increased as clinical symptoms became more severe. Cerebral blood flow (CBF) values were lower, cerebral blood volume (CBV) values were higher, and CBF/CBV values were lower than those of controls as symptoms became severe (p < 0.05). CBF and CBF/CBV values decreased and CBV values increased as the ivy sign score increased, and were significantly higher and lower, respectively, than control values (p < 0.05). No significant differences in cerebral metabolic rate of oxygen and oxygen extraction fraction were found between the 3 ivy sign scores. A positive correlation was found between ivy sign score and increases in CBV (p < 0.01), and a more obvious negative correlation was found between ivy sign

  10. [Cerebral blood flow and oxygen extraction in lacunar hemiplegia. Semi-quantitative study using oxygen 15 and emission tomography].

    PubMed

    Rougemont, D; Baron, J C; Lebrun-Grandie, P; Bousser, M G; Cabanis, E; Laplane, D

    1983-01-01

    The oxygen 15 non invasive continuous inhalation technique coupled with positron emission tomography (P.E.T.) allows the local study of cerebral blood flow and oxygen metabolism. Recent P.E.T. studies have demonstrated the frequent occurrence of widespread metabolic depression remote from the site of middle cerebral artery territory infarct per se, especially over the cortical mantle and thalamus ipsilaterally, and over the cerebellar hemisphere contralaterally. These phenomena have been taken as indicative of transneural depression (i.e. diaschisis). We thought it interesting to study the possible occurrence of such abnormalities in patients with lacunar syndromes. We have applied the (15)0 technique to six patients (2 with pure motor hemiplegia, 4 with ataxic hemiparesis) for whom no large causal ischemic lesion could be demonstrated on CT scans; in only one patient was a lacunar lesion, presumably responsible for the clinical deficit demonstrated. Compared to a set of 19 patients without brain disease, the semi-quantitative results (analyzed in terms of asymmetry indices between homologous brain regions) in our patients did not disclose any pathophysiologically significant abnormality. More specifically, no evidence of physiological dysfunction similar to that reported in internal carotid artery territory infarcts, was detected over the cerebral or cerebellar cortices. These findings are commented upon in view of the presumably small size and the uncertain topography of the causal lesion.

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

    PubMed Central

    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

    2013-01-01

    Through the combined use of 18F-fallypride positron emission tomography and magnetic resonance imaging this study examined the neural mechanisms underlying the attentional deficits associated with attention deficit/hyperactivity disorder and their potential reversal with a single therapeutic dose of methylphenidate. Sixteen adult patients with attention deficit/hyperactivity disorder and 16 matched healthy control subjects were positron emission tomography and magnetic resonance imaging 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

  12. Decrease of prefrontal metabolism after subthalamic stimulation in obsessive-compulsive disorder: a positron emission tomography study.

    PubMed

    Le Jeune, Florence; Vérin, Marc; N'Diaye, Karim; Drapier, Dominique; Leray, Emmanuelle; Du Montcel, Sophie Tezenas; Baup, Nicolas; Pelissolo, Antoine; Polosan, Mircea; Mallet, Luc; Yelnik, Jérome; Devaux, Bertrand; Fontaine, Denys; Chereau, Isabelle; Bourguignon, Aurélie; Peron, Julie; Sauleau, Paul; Raoul, Sylvie; Garin, Etienne; Krebs, Marie-Odile; Jaafari, Nematollah; Millet, Bruno

    2010-12-01

    High-frequency bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) is a promising treatment in refractory obsessive-compulsive disorder (OCD). Using the crossover, randomized, and double-blind procedure adopted by the STOC study, 10 patients treated with high-frequency bilateral STN DBS underwent am 18-fluorodeoxyglucose positron emission tomography (PET) investigation to highlight the neural substratum of this therapeutic approach. The median Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores for all 10 patients were 31 (minimum = 18, maximum = 36) with "Off-Stimulation" status and 19 (minimum = 0, maximum = 30) with "On-Stimulation" status (p = .05). The OCD patients in Off-Stimulation status showed a hypermetabolism in the right frontal middle and superior gyri, right parietal lobe, postcentral gyrus, and bilateral putamen compared with healthy control subjects. A significant decrease in cerebral metabolism was observed in the left cingulate gyrus and the left frontal medial gyrus in On-Stimulation conditions compared with Off-Stimulation conditions. In addition, the improvement assessed by Y-BOCS scores during the On-Stimulation conditions was positively correlated with PET signal changes at the boundary of the orbitofrontal cortex and the medial prefrontal cortex, between PET signal changes and the Y-BOCS scores modifications in On-Stimulation status. This study suggests that the therapeutic effect of STN DBS is related to a decrease in prefrontal cortex metabolism. Copyright © 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  13. 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.

  14. Positron emission tomography (PET) for cholangiocarcinoma

    PubMed Central

    Breitenstein, S.; Apestegui, C.

    2008-01-01

    The combination of positron emission tomography (PET) with computed tomography (PET-CT) provides simultaneous metabolic and anatomic information on tumors in the same imaging session. Sensitivity of PET/PET-CT is higher for intrahepatic (>90%) than for extrahepatic cholangiocarcinoma (CCA) (about 60%). The detection rate of distant metastasis is 100%. PET, and particularly PET-CT, improves the results and impacts on the oncological management in CCA compared with other imaging modalities. Therefore, PET-CT is recommended in the preoperative staging of intrahepatic (strength of recommendation: moderate) and extrahepatic (strength of recommendation: low) CCA. PMID:18773069

  15. 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.

  16. Cerebral metabolic rate for glucose during the first six months of life: an FDG positron emission tomography study.

    PubMed Central

    Kinnala, A.; Suhonen-Polvi, H.; Aärimaa, T.; Kero, P.; Korvenranta, H.; Ruotsalainen, U.; Bergman, J.; Haaparanta, M.; Solin, O.; Nuutila, P.; Wegelius, U.

    1996-01-01

    AIM: To measure the local cerebral metabolic rate for glucose (LCMRGlc) in neonatal brains during maturation using positron emission tomography (PET) and 2-[18F]fluoro-2-deoxy-D-glucose (FDG). METHODS: Twenty infants were studied using PET during the neonatal period. The postconceptional age ranged from 32.7 to 60.3 weeks. All infants had normal neurodevelopment and were normoglycaemic. The development of the infants was carefully evaluated (follow up 12-36 months) clinically, and by using a method based on Gesell Amatruda's developmental diagnosis. LCMRGlc was quantitated using PET derived from FDG kinetics and calculated in the whole brain and for regional brain structures. RESULTS: LCMRGlc for various cortical brain regions and the basal ganglia was low at birth (from 4 to 16 mumol/100 g/minute). In infants 2 months of age and younger LCMRGlc was highest in the sensorimotor cortex, thalamus, and brain stem. By 5 months, LCMRGlc had increased in the frontal, parietal, temporal, occipital and cerebellar cortical regions. In general, the whole brain LCMRGlc correlated with postconceptional age (r = 0.90; P < 0.001). The change in the glucose metabolic pattern observed in the neonatal brain reflects the functional maturation of these brain regions. CONCLUSION: These findings show that LCMRGlc in infants increases with maturation. Accordingly, when LCMRGlc is measured during infancy, the postconceptional age has to be taken into account when interpretating the results. Images Figure 1 PMID:8777676

  17. Estradiol modulates neural response to conspecific and heterospecific song in female house sparrows: An in vivo positron emission tomography study

    PubMed Central

    Stabile, Frank A.; Carson, Richard E.

    2017-01-01

    Although there is growing evidence that estradiol modulates female perception of male sexual signals, relatively little research has focused on female auditory processing. We used in vivo 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging to examine the neuronal effects of estradiol and conspecific song in female house sparrows (Passer domesticus). We assessed brain glucose metabolism, a measure of neuronal activity, in females with empty implants, estradiol implants, and empty implants ~1 month after estradiol implant removal. Females were exposed to conspecific or heterospecific songs immediately prior to imaging. The activity of brain regions involved in auditory perception did not differ between females with empty implants exposed to conspecific vs. heterospecific song, but neuronal activity was significantly reduced in females with estradiol implants exposed to heterospecific song. Furthermore, our within-individual design revealed that changes in brain activity due to high estradiol were actually greater several weeks after peak hormone exposure. Overall, this study demonstrates that PET imaging is a powerful tool for assessing large-scale changes in brain activity in living songbirds, and suggests that after breeding is done, specific environmental and physiological cues are necessary for estradiol-stimulated females to lose the selectivity they display in neural response to conspecific song. PMID:28832614

  18. Altered regional cerebral glucose metabolism in internet game overusers: a 18F-fluorodeoxyglucose positron emission tomography study.

    PubMed

    Park, Hyun Soo; Kim, Sang Hee; Bang, Seong Ae; Yoon, Eun Jin; Cho, Sang Soo; Kim, Sang Eun

    2010-03-01

    Internet game overuse is an emerging disorder and features diminished impulse control and poor reward-processing. In an attempt to understand the neurobiological bases of Internet game overuse, we investigated the differences in regional cerebral glucose metabolism at resting state between young individuals with Internet game overuse and those with normal use using 18F-fluorodeoxyglucose positron emission tomography study. Twenty right-handed male participants (9 normal users: 24.7+/-2.4 years of age, 11 overusers: 23.5+/-2.9 years of age) participated. A trait measure of impulsivity was also completed after scanning. Internet game overusers showed greater impulsiveness than the normal users and there was a positive correlation between the severity of Internet game overuse and impulsiveness. Imaging data showed that the overusers had increased glucose metabolism in the right middle orbitofrontal gyrus, left caudate nucleus, and right insula, and decreased metabolism in the bilateral postcentral gyrus, left precentral gyrus, and bilateral occipital regions compared to normal users. Internet game overuse may be associated with abnormal neurobiological mechanisms in the orbitofrontal cortex, striatum, and sensory regions, which are implicated in impulse control, reward processing, and somatic representation of previous experiences. Our results support the idea that Internet game overuse shares psychological and neural mechanisms with other types of impulse control disorders and substance/non-substance-related addiction.

  19. Studies on functional roles of the histaminergic neuron system by using pharmacological agents, knockout mice and positron emission tomography.

    PubMed

    Watanabe, T; Yanai, K

    2001-12-01

    Since one of us, Takehiko Watanabe (TW), elucidated the location and distribution of the histaminergic neuron system in the brain with antibody raised against L-histidine decarboxylase (a histamine-forming enzyme, HDC) as a marker in 1984 and came to Tohoku University School of Medicine in Sendai, we have been collaborating on the functions of this neuron system by using pharmacological agents, knockout mice of the histamine-related genes, and, in some cases, positron emission tomography (PET). Many of our graduate students and colleagues have been actively involved in histamine research since 1985. Our extensive studies have clarified some of the functions of histamine neurons using methods from molecular techniques to non-invasive human PET imaging. Histamine neurons are involved in many brain functions, such as spontaneous locomotion, arousal in wake-sleep cycle, appetite control, seizures, learning and memory, aggressive behavior and emotion. Particularly, the histaminergic neuron system is one of the most important neuron systems to maintain and stimulate wakefulness. Histamine also functions as a bioprotection system against various noxious and unfavorable stimuli (for examples, convulsion, nociception, drug sensitization, ischemic lesions, and stress). Although activators of histamine neurons have not been clinically available until now, we would like to point out that the activation of the histaminergic neuron system is important to maintain mental health. Here, we summarize the newly-discovered functions of histamine neurons mainly on the basis of results from our research groups.

  20. Brain metabolism of children with profound deafness: a visual language activation study by 18F-fluorodeoxyglucose positron emission tomography.

    PubMed

    Fujiwara, Keizo; Naito, Yasushi; Senda, Michio; Mori, Toshiko; Manabe, Tomoko; Shinohara, Shogo; Kikuchi, Masahiro; Hori, Shin-Ya; Tona, Yosuke; Yamazaki, Hiroshi

    2008-04-01

    The use of fluorodeoxyglucose positron emission tomography (FDG-PET) with a visual language task provided objective information on the development and plasticity of cortical language networks. This approach could help individuals involved in the habilitation and education of prelingually deafened children to decide upon the appropriate mode of communication. To investigate the cortical processing of the visual component of language and the effect of deafness upon this activity. Six prelingually deafened children participated in this study. The subjects were numbered 1-6 in the order of their spoken communication skills. In the time period between an intravenous injection of 370 MBq 18F-FDG and PET scanning of the brain, each subject was instructed to watch a video of the face of a speaking person. The cortical radioactivity of each deaf child was compared with that of a group of normal- hearing adults using a t test in a basic SPM2 model. The widest bilaterally activated cortical area was detected in subject 1, who was the worst user of spoken language. By contrast, there was no significant difference between subject 6, who was the best user of spoken language with a hearing aid, and the normal hearing group.

  1. 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.

  2. Positron emission tomography in the evaluation of subdural hematomas

    SciTech Connect

    Ericson, K.; Bergstroem, M.; Eriksson, L.

    1980-12-01

    Fifteen patients with 21 subdural effusions were investigated both with transmission computer assisted tomography (CAT) and positron emission tomography (PET). The tracer in the emission studies was /sup 68/Ga-EDTA. Twelve lesions were visualized both with CAT and PET. Five lesions that were negative or doubtful on CAT were visualized with PET, whereas four lesions negative or doubtful on PET were demonstrated by CAT. The two methods complement each other due to the fact that they are based on different mechanisms: CAT mainly on attenuation of the fluid collection. PET on isotope accumulation, particularly in the hematoma membranes.

  3. Positron Emission Tomography Imaging of Hypoxia

    PubMed Central

    Lapi, Suzanne E.; Voller, Thomas F.; Welch, Michael J.

    2009-01-01

    Synopsis Hypoxia imaging has applications in functional recovery in ischemic events such as stroke and myocardial ischemia, but especially in tumors in which hypoxia can be predictive of treatment response and overall prognosis. Recently there has been development of imaging agents utilizing positron emission tomography for non-invasive imaging of hypoxia. Many of these PET agents have come to the forefront of hypoxia imaging. Halogenated PET nitroimidazole imaging agents labeled with 18F (t1/2 = 110 m) and 124I (t1/2 = 110 m) have been under investigation for the last 25 years, with radiometal agents (64Cu-ATSM) being developed more recently. This review focuses on these positron emission tomography imaging agents for hypoxia. PMID:20046923

  4. A positron emission tomography microdosing study with a potential antiamyloid drug in healthy volunteers and patients with Alzheimer's disease.

    PubMed

    Bauer, Martin; Langer, Oliver; Dal-Bianco, Peter; Karch, Rudolf; Brunner, Martin; Abrahim, Aiman; Lanzenberger, Rupert; Hofmann, Andrea; Joukhadar, Christian; Carminati, Paolo; Ghirardi, Orlando; Piovesan, Paola; Forloni, Gianluigi; Corrado, Mario E; Lods, Nadège; Dudczak, Robert; Auff, Eduard; Kletter, Kurt; Müller, Markus

    2006-09-01

    This work describes a microdosing study with an investigational, carbon 11-labeled antiamyloid drug, 1,1'-methylene-di-(2-naphthol) (ST1859), and positron emission tomography (PET) in healthy volunteers (n = 3) and patients with Alzheimer's disease (n = 6). The study aimed to assess the distribution and local tissue pharmacokinetics of the study drug in its target organ, the human brain. Before PET studies were performed in humans, the toxicologic characteristics of ST1859 were investigated by an extended single-dose toxicity study according to guidelines of the Food and Drug Administration and European Medicines Agency, which are relevant for clinical trials with a single microdose. After intravenous bolus injection of 341 +/- 21 MBq [(11)C]ST1859 (containing <11.4 nmol of unlabeled ST1859), peripheral metabolism was rapid, with less than 20% of total plasma radioactivity being in the form of unchanged parent drug at 10 minutes after administration. In both the control and patient groups, uptake of radioactivity into the brain was relatively fast (time to reach maximum concentration, 9-17 minutes) and pronounced (maximum concentration [standardized uptake value], 1.3-2.2). In both healthy volunteers and patients, there was a rather uniform distribution of radioactivity in the brain, including both amyloid-beta-rich and -poor regions, with slow washout of radioactivity (half-life, 82-185 minutes). In conclusion, these data provide important information on the blood-brain barrier penetration and metabolism of an investigational antiamyloid drug and suggest that the PET microdosing approach is a useful method to describe the target-organ pharmacokinetics of radiolabeled drugs in humans.

  5. Aerosol Delivery with Two Nebulizers Through High-Flow Nasal Cannula: A Randomized Cross-Over Single-Photon Emission Computed Tomography-Computed Tomography Study.

    PubMed

    Dugernier, Jonathan; Hesse, Michel; Jumetz, Thibaud; Bialais, Emilie; Roeseler, Jean; Depoortere, Virginie; Michotte, Jean-Bernard; Wittebole, Xavier; Ehrmann, Stephan; Laterre, Pierre-François; Jamar, François; Reychler, Gregory

    2017-10-01

    High-flow nasal cannula use is developing in ICUs. The aim of this study was to compare aerosol efficiency by using two nebulizers through a high-flow nasal cannula: the most commonly used jet nebulizer (JN) and a more efficient vibrating-mesh nebulizer (VN). Aerosol delivery of diethylenetriaminepentaacetic acid labeled with technetium-99m (4 mCi/4 mL) to the lungs by using a VN (Aerogen Solo(®); Aerogen Ltd., Galway, Ireland) and a constant-output JN (Opti-Mist Plus Nebulizer(®); ConvaTec, Bridgewater, NJ) through a high-flow nasal cannula (Optiflow(®); Fisher & Paykel, New Zealand) was compared in six healthy subjects. Flow rate was set at 30 L/min through the heated humidified circuit. Pulmonary and extrapulmonary deposition was measured by single-photon emission computed tomography combined with a low-dose computed tomographic scan and by planar scintigraphy. Lung deposition was only 3.6 (2.1-4.4) and 1 (0.7-2)% of the nominal dose with the VN and the JN, respectively (p < 0.05). The JN showed higher retained doses than the VN. However, both nebulizers were associated with substantial deposition in the single limb circuit, the humidification chamber, and the nasal cannula [58.2 (51.6-61.6)% of the nominal dose with the VN versus 19.2 (15.8-22.9)% of the nominal dose with the JN, p < 0.05] and in the upper respiratory tract [17.6 (13.4-27.9)% of the nominal dose with the VN and 8.6 (6.0-11.0)% of the nominal dose with the JN, p < 0.05], especially in the nasal cavity. In the specific conditions of the study, pulmonary drug delivery through the high-flow nasal cannula is about 1%-4% of the initial amount of drugs placed in the nebulizer, despite the higher efficiency of the VN as compared with the JN.

  6. Amorphous silicon detectors in positron emission tomography

    SciTech Connect

    Conti, M. Lawrence Berkeley Lab., CA ); Perez-Mendez, V. )

    1989-12-01

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

  7. Effect of Cigarette Smoking on a Marker for Neuroinflammation: A [(11)C]DAA1106 Positron Emission Tomography Study.

    PubMed

    Brody, Arthur L; Hubert, Robert; Enoki, Ryutaro; Garcia, Lizette Y; Mamoun, Michael S; Okita, Kyoji; London, Edythe D; Nurmi, Erika L; Seaman, Lauren C; Mandelkern, Mark A

    2017-03-06

    In the brain, microglia continuously scan the surrounding extracellular space, in order to respond to damage or infection by becoming activated and participating in neuroinflammation. When activated, microglia increase the expression of the translocator protein (TSPO) 18 kDa, thereby making TSPO expression a marker for neuroinflammation. We used the radiotracer [(11)C]DAA1106 (a ligand for TSPO) and positron emission tomography (PET) to determine the effect of smoking on availability of this marker for neuroinflammation. Forty-five participants (30 smokers and 15 non-smokers) completed the study and had usable data. Participants underwent a dynamic PET scanning session with bolus injection of [(11)C]DAA1106 (with smokers in the satiated state) and blood draws during PET scanning to determine TSPO affinity genotype and plasma nicotine levels. Whole brain standardized uptake values (SUVs) were determined, and analysis of variance was performed, with group (smoker vs non-smoker) and genotype as factors, thereby controlling for genotype. Smokers and non-smokers differed in whole brain SUVs (P=0.006) due to smokers having 16.8% lower values than non-smokers. The groups did not differ in injected radiotracer dose or body weight, which were used to calculate SUV. An inverse association was found between whole brain SUV and reported cigarettes per day (P<0.05), but no significant relationship was found for plasma nicotine. Thus, smokers have less [(11)C]DAA1106 binding globally than nonsmokers, indicating less microglial activation. Study findings are consistent with much prior research demonstrating that smokers have impaired inflammatory functioning compared to non-smokers and that constituents of tobacco smoke other than nicotine affect inflammatory processes.Neuropsychopharmacology accepted article preview online, 06 March 2017. doi:10.1038/npp.2017.48.

  8. Heterogeneity of Monosymptomatic Resting Tremor in a Prospective Study: Clinical Features, Electrophysiological Test, and Dopamine Transporter Positron Emission Tomography

    PubMed Central

    Zheng, Hua-Guang; Zhang, Rong; Li, Xin; Li, Fang-Fei; Wang, Ya-Chen; Wang, Xue-Mei; Lu, Ling-Long; Feng, Tao

    2015-01-01

    Background: The relationship between monosymptomatic resting tremor (mRT) and Parkinson's disease (PD) remains controversial. In this study, we aimed to assess the function of presynaptic dopaminergic neurons in patients with mRT by dopamine transporter positron emission tomography (DAT-PET) and to evaluate the utility of clinical features or electrophysiological studies in differential diagnosis. Methods: Thirty-three consecutive patients with mRT were enrolled prospectively. The Unified Parkinson's Disease Rating Scale and electromyography were tested before DAT-PET. Striatal asymmetry index (SAI) was calculated, and a normal DAT-PET was defined as a SAI of <15%. Scans without evidence of dopaminergic deficits (SWEDDs) were diagnosed in patients with a subsequent normal DAT-PET and structural magnetic resonance imaging. Results: Twenty-eight mRT patients with a significant reduction in uptake of DAT binding in the striatum were diagnosed with PD, while the remained 5 with a normal DAT-PET scan were SWEDDs. As for UPRDS, the dressing and hygiene score, walking in motor experiences of daily living (Part II) and motor examination (Part III) were significant different between two groups (P < 0.05 and P < 0.01, respectively). Bilateral tremor was more frequent in the SWEDDs group (P < 0.05). The frequency of resting tremor and the amplitude of postural tremor tend to be higher in the SWEDDs group (P = 0.08 and P = 0.05, respectively). Conclusions: mRT is heterogeneous in presynaptic nigrostriatal dopaminergic degeneration, which can be determined by DAT-PET brain imaging. Clinical and electrophysiological features may provide clues to distinguish PD from SWEDDs. PMID:26112718

  9. Heterogeneity of Monosymptomatic Resting Tremor in a Prospective Study: Clinical Features, Electrophysiological Test, and Dopamine Transporter Positron Emission Tomography.

    PubMed

    Zheng, Hua-Guang; Zhang, Rong; Li, Xin; Li, Fang-Fei; Wang, Ya-Chen; Wang, Xue-Mei; Lu, Ling-Long; Feng, Tao

    2015-07-05

    The relationship between monosymptomatic resting tremor (mRT) and Parkinson's disease (PD) remains controversial. In this study, we aimed to assess the function of presynaptic dopaminergic neurons in patients with mRT by dopamine transporter positron emission tomography (DAT-PET) and to evaluate the utility of clinical features or electrophysiological studies in differential diagnosis. Thirty-three consecutive patients with mRT were enrolled prospectively. The Unified Parkinson's Disease Rating Scale and electromyography were tested before DAT-PET. Striatal asymmetry index (SAI) was calculated, and a normal DAT-PET was defined as a SAI of <15%. Scans without evidence of dopaminergic deficits (SWEDDs) were diagnosed in patients with a subsequent normal DAT-PET and structural magnetic resonance imaging. Twenty-eight mRT patients with a significant reduction in uptake of DAT binding in the striatum were diagnosed with PD, while the remained 5 with a normal DAT-PET scan were SWEDDs. As for UPRDS, the dressing and hygiene score, walking in motor experiences of daily living (Part II) and motor examination (Part III) were significant different between two groups (P < 0.05 and P < 0.01, respectively). Bilateral tremor was more frequent in the SWEDDs group (P < 0.05). The frequency of resting tremor and the amplitude of postural tremor tend to be higher in the SWEDDs group (P = 0.08 and P = 0.05, respectively). mRT is heterogeneous in presynaptic nigrostriatal dopaminergic degeneration, which can be determined by DAT-PET brain imaging. Clinical and electrophysiological features may provide clues to distinguish PD from SWEDDs.

  10. Elevated brain cannabinoid CB1 receptor availability in post-traumatic stress disorder: a positron emission tomography study.

    PubMed

    Neumeister, A; Normandin, M D; Pietrzak, R H; Piomelli, D; Zheng, M Q; Gujarro-Anton, A; Potenza, M N; Bailey, C R; Lin, S F; Najafzadeh, S; Ropchan, J; Henry, S; Corsi-Travali, S; Carson, R E; Huang, Y

    2013-09-01

    Endocannabinoids and their attending cannabinoid type 1 (CB1) receptor have been implicated in animal models of post-traumatic 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 [(11)C]OMAR in individuals with PTSD, and healthy controls with lifetime histories of trauma (trauma-exposed 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 imaging scan and a resting PET scan with the CB1 receptor antagonist radiotracer [(11)C]OMAR, which measures the volume of distribution (VT) linearly related to CB1 receptor availability. Peripheral levels of anandamide, 2-arachidonoylglycerol, oleoylethanolamide, palmitoylethanolamide and cortisol were also assessed. In the PTSD group, relative to the HC and TC groups, we found elevated brain-wide [(11)C]OMAR VT values (F(2,53)=7.96, P=0.001; 19.5% and 14.5% higher, respectively), which were most pronounced in women (F(1,53)=5.52, P=0.023). 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.

  11. Temperament, character and serotonin activity in the human brain: a positron emission tomography study based on a general population cohort.

    PubMed

    Tuominen, L; Salo, J; Hirvonen, J; Någren, K; Laine, P; Melartin, T; Isometsä, E; Viikari, J; Cloninger, C R; Raitakari, O; Hietala, J; Keltikangas-Järvinen, L

    2013-04-01

    The psychobiological model of personality by Cloninger and colleagues originally hypothesized that interindividual variability in the temperament dimension 'harm avoidance' (HA) is explained by differences in the activity of the brain serotonin system. We assessed brain serotonin transporter (5-HTT) density in vivo with positron emission tomography (PET) in healthy individuals with high or low HA scores using an 'oversampling' study design. Method Subjects consistently in either upper or lower quartiles for the HA trait were selected from a population-based cohort in Finland (n = 2075) with pre-existing Temperament and Character Inventory (TCI) scores. A total of 22 subjects free of psychiatric and somatic disorders were included in the matched high- and low-HA groups. The main outcome measure was regional 5-HTT binding potential (BPND) in high- and low-HA groups estimated with PET and [11C]N,N-dimethyl-2-(2-amino-4-methylphenylthio)benzylamine ([11C]MADAM). In secondary analyses, 5-HTT BPND was correlated with other TCI dimensions. 5-HTT BPND did not differ between high- and low-HA groups in the midbrain or any other brain region. This result remained the same even after adjusting for other relevant TCI dimensions. Higher 5-HTT BPND in the raphe nucleus predicted higher scores in 'self-directedness'. This study does not support an association between the temperament dimension HA and serotonin transporter density in healthy subjects. However, we found a link between high serotonin transporter density and high 'self-directedness' (ability to adapt and control one's behaviour to fit situations in accord with chosen goals and values). We suggest that biological factors are more important in explaining variability in character than previously thought.

  12. 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.

  13. Three-dimensional visualization of cardiac single-photon-emission computed-tomography studies

    NASA Astrophysics Data System (ADS)

    Cooke, C. D.; Garcia, Ernest V.; Folks, Russell D.; Peifer, John W.

    1992-09-01

    We have previously reported on a method for visualizing cardiovascular nuclear medicine tomographic perfusion studies which included: long and short axis slices, two-dimensional (2- D) polar maps, three-dimensional (3-D) surface models, and four-dimensional surface models. We have since validated the 3-D surface model in a prospective patient population, added the ability to generate 3-D models from any polar map, and added a panoramic display that allows two 3-D models to be compared side-by-side. This paper describes the methodologies involved in these enhancements.

  14. 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

    2012-01-07

    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.

  15. The neuronal component of gray matter damage in multiple sclerosis: A [(11) C]flumazenil positron emission tomography study.

    PubMed

    Freeman, Léorah; Garcia-Lorenzo, Daniel; Bottin, Laure; Leroy, Claire; Louapre, Céline; Bodini, Benedetta; Papeix, Caroline; Assouad, Rana; Granger, Benjamin; Tourbah, Ayman; Dollé, Frédéric; Lubetzki, Catherine; Bottlaender, Michel; Stankoff, Bruno

    2015-10-01

    Using positron emission tomography (PET) with [(11) C]flumazenil ([(11) C]FMZ), an antagonist of the central benzodiazepine site located within the GABAA receptor, we quantified and mapped neuronal damage in the gray matter (GM) of patients with multiple sclerosis (MS) at distinct disease stages. We investigated the relationship between neuronal damage and white matter (WM) lesions and evaluated the clinical relevance of this neuronal PET metric. A cohort of 18 MS patients (9 progressive and 9 relapsing-remitting) was compared to healthy controls and underwent neurological and cognitive evaluations, high-resolution dynamic [(11) C]FMZ PET imaging and brain magnetic resonance imaging. [(11) C]FMZ binding was estimated using the partial saturation protocol providing voxel-wise absolute quantification of GABAA receptor concentration. PET data were evaluated using a region of interest (ROI) approach as well as on a vertex-by-vertex basis. [(11) C]FMZ binding was significantly decreased in the cortical GM of MS patients, compared to controls (-10%). Cortical mapping of benzodiazepine receptor concentration ([(11) C]FMZ Bmax) revealed significant intergroup differences in the bilateral parietal cortices and right frontal areas. ROI analyses taking into account GM volume changes showed extensive decrease in [(11) C]FMZ binding in bilateral parietal, cingulate, and insular cortices as well as in the thalami, amygdalae, and hippocampi. These changes were significant in both progressive and relapsing-remitting forms of the disease and correlated with WM T2-weighted lesion load. [(11) C]FMZ cortical binding correlated with cognitive performance. This pilot study showed that PET with [(11) C]FMZ could be a promising and sensitive quantitative marker to assess and map the neuronal substrate of GM pathology in MS. © 2015 American Neurological Association.

  16. Review. Positron emission tomography imaging studies of dopamine receptors in primate models of addiction.

    PubMed

    Nader, Michael A; Czoty, Paul W; Gould, Robert W; Riddick, Natallia V

    2008-10-12

    Animal models have provided valuable information related to trait and state variables associated with vulnerability to drug addiction. Our brain imaging studies in monkeys have implicated D2 receptors in cocaine addiction. For example, an inverse relationship between D2 receptor availability and rates of cocaine self-administration has been documented. Moreover, environmental variables, such as those associated with formation of the social hierarchy, can impact receptor availability and sensitivity to the abuse-related effects of cocaine. Similarly, both D2 receptor availability and cocaine self-administration can be altered by chronic drug administration and fluctuations in hormone levels. In addition, cocaine self-administration can be altered in an orderly fashion by presentation of an acute stressor, such as acting as an intruder into an unfamiliar social group, which can shift the cocaine dose-response curve to the left in subordinate monkeys and to the right in dominant animals, suggesting an interaction between social variables and acute stressors. Conversely, irrespective of social rank, acute environmental enrichment, such as increasing the size of the living space, shifts the cocaine dose-response curve to the right. These findings highlight a pervasive influence of the environment in modifying the reinforcing effects of cocaine and strongly implicate brain D2 receptors.

  17. 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.

  18. Positron-emission tomography and personality disorders.

    PubMed

    Goyer, P F; Andreason, P J; Semple, W E; Clayton, A H; King, A C; Compton-Toth, B A; Schulz, S C; Cohen, R M

    1994-02-01

    This study used positron-emission tomography to examine cerebral metabolic rates of glucose (CMRG) in 17 patients with DSM III-R diagnoses of personality disorder. Within the group of 17 personality disorder patients, there was a significant inverse correlation between a life history of aggressive impulse difficulties and regional CMRG in the frontal cortex of the transaxial plane approximately 40 mm above the canthomeatal line (CML) (r = -.56, p = 0.17). Diagnostic groups included antisocial (n = 6), borderline (n = 6), dependent (n = 2), and narcissistic (n = 3). Regional CMRG in the six antisocial patients and in the six borderline patients was compared to a control group of 43 subjects using an analysis of covariance with age and sex as covariates. In the borderline personality disorder group, there was a significant decrease in frontal cortex metabolism in the transaxial plane approximately 81 mm above the CML and a significant increase in the transaxial plane approximately 53 mm above the CML (F[1,45] = 8.65, p = .005; and F[1,45] = 7.68, p = .008, respectively.

  19. Positron emission tomography combined with computed tomography as a screening tool for occult malignancy in patients with unprovoked venous thromboembolism: an observational study.

    PubMed

    Chauchard, Maria; Benali, Khadija; Papo, Thomas; Sacre, Karim

    2014-11-01

    Venous thromboembolism (VTE) can be the first clinical manifestation of an occult malignancy. We aimed to assess the value, in daily practice, of positron emission tomography combined with computed tomography (PET-CT) for occult malignancy diagnosis in patients with unprovoked VTE.All PET-CTs performed over 5-years period (from January 2009 to October 2013) in adult patients followed in the Department of Internal Medicine (Bichat Hospital, Paris, France) were retrospectively reviewed. Clinical history, imaging findings, and additional diagnostic tests performed because of PET-CT findings were analyzed.From January 2009 to October 2013, PET-CT was performed for malignancy diagnosis in 67 consecutive patients with unprovoked VTE. Seventeen patients were excluded because of congenital or acquired thrombophilia, known cancer, estrogen use, inability to confirm VTE diagnosis, or missing data. Fifty patients (25 women; mean age, 65.2 ± 15.9 years) were included. VTE was a first episode in 84% of cases. In 22 (44%) patients, PET-CT showed increased uptake suspicious for malignancy. After additional procedures, malignancy was confirmed in 12/22 patients. In all cases of confirmed malignancies, conventional computed tomography scan (CT-scan) had similar diagnosis yield, as compared with PET-CT. In 10/22 cases, the suspected diagnosis of malignancy could not be confirmed despite extensive workup including specialist visits (n = 5), magnetic resonance imaging (n = 4), gastrointestinal tract endoscopy (n = 3), endometrial biopsies (n = 2), and hysterectomy (n = 1). The cost of additional diagnosis procedures performed because of false positive PET-CT amounted to є1956/patient. Interestingly, considering CT-scan findings only, no further investigation would have been scheduled. No patient with negative or false positive PET-CT was diagnosed with cancer during a mean follow-up of 22 ± 13.6 months.A diagnosis strategy based on PET-CT screening for

  20. 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.

  1. Single photon emission computed tomography-guided Cerenkov luminescence tomography

    NASA Astrophysics Data System (ADS)

    Hu, Zhenhua; Chen, Xueli; Liang, Jimin; Qu, Xiaochao; Chen, Duofang; Yang, Weidong; Wang, Jing; Cao, Feng; Tian, Jie

    2012-07-01

    Cerenkov luminescence tomography (CLT) has become a valuable tool for preclinical imaging because of its ability of reconstructing the three-dimensional distribution and activity of the radiopharmaceuticals. However, it is still far from a mature technology and suffers from relatively low spatial resolution due to the ill-posed inverse problem for the tomographic reconstruction. In this paper, we presented a single photon emission computed tomography (SPECT)-guided reconstruction method for CLT, in which a priori information of the permissible source region (PSR) from SPECT imaging results was incorporated to effectively reduce the ill-posedness of the inverse reconstruction problem. The performance of the method was first validated with the experimental reconstruction of an adult athymic nude mouse implanted with a Na131I radioactive source and an adult athymic nude mouse received an intravenous tail injection of Na131I. A tissue-mimic phantom based experiment was then conducted to illustrate the ability of the proposed method in resolving double sources. Compared with the traditional PSR strategy in which the PSR was determined by the surface flux distribution, the proposed method obtained much more accurate and encouraging localization and resolution results. Preliminary results showed that the proposed SPECT-guided reconstruction method was insensitive to the regularization methods and ignored the heterogeneity of tissues which can avoid the segmentation procedure of the organs.

  2. [Positron emission tomography/computed tomography in rheumatology].

    PubMed

    Derlin, T

    2017-06-29

    Combined positron emission tomography/computed tomography (PET/CT) is a whole-body imaging procedure, which enables sensitive detection of inflammatory changes. It may be used to simultaneously obtain both precise anatomical and molecular information in order to comprehensively characterize diseases. The glucose analogue (18)F-fluorodeoxyglucose (FDG) represents a universally applicable radiotracer for imaging of inflammatory processes. Its accumulation in tissues can be semiquantitatively characterized by use of standardized uptake values (SUV). In principle, a broad spectrum of infectious and non-infectious inflammatory and malignant diseases can be imaged. (18)F-FDG PET/CT has become a valuable modality and is increasingly being used for evaluation of large vessel vasculitis and for evaluation of elevated systemic inflammatory markers without known cause. Beside the radiotracer (18)F-FDG, other radiopharmaceuticals enable a non-invasive analysis of additional parameters of inflammatory disorders, such as other metabolic pathways or the expression of surface receptors.

  3. 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.

  4. 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.

  5. Future direction of renal positron emission tomography.

    PubMed

    Szabo, Zsolt; Xia, Jinsong; Mathews, William B; Brown, Phillip R

    2006-01-01

    Positron emission tomography (PET) is perfectly suited for quantitative imaging of the kidneys, and the recent improvements in detector technology, computer hardware, and image processing software add to its appeal. Multiple positron emitting radioisotopes can be used for renal imaging. Some, including carbon-11, nitrogen-13, and oxygen-15, can be used at institutions with an on-site cyclotron. Other radioisotopes that may be even more useful in a clinical setting are those that either can be obtained from radionuclide generators (rubidium-82, copper-62) or have a sufficiently long half-life for transportation (fluorine-18). The clinical use of functional renal PET studies (blood flow, glomerular filtration rate) has been slow, in part because of the success of concurrent technologies, including single-photon emission computed tomography (SPECT) and planar gamma camera imaging. Renal blood flow studies can be performed with O-15-labeled water, N-13-labeled ammonia, rubidium-82, and copper-labeled PTSM. With these tracers, renal blood flow can be quantified using a modified microsphere kinetic model. Glomerular filtration can be imaged and quantified with gallium-68 EDTA or cobalt-55 EDTA. Measurements of renal blood flow with PET have potential applications in renovascular disease, in transplant rejection or acute tubular necrosis, in drug-induced nephropathies, ureteral obstruction, before and after revascularization, and before and after the placement of ureteral stents. The most important clinical application for imaging glomerular function with PET would be renovascular hypertension. Molecular imaging of the kidneys with PET is rather limited. At present, research is focused on the investigation of metabolism (acetate), membrane transporters (organic cation and anion transporters, pepT1 and pepT2, GLUT, SGLT), enzymes (ACE), and receptors (AT1R). Because many nephrological and urological disorders are initiated at the molecular and organelle levels and may

  6. Introduction to neutron stimulated emission computed tomography.

    PubMed

    Floyd, Carey E; Bender, Janelle E; Sharma, Amy C; Kapadia, Anuj; Xia, Jessie; Harrawood, Brian; Tourassi, Georgia D; Lo, Joseph Y; Crowell, Alexander; Howell, Calvin

    2006-07-21

    Neutron stimulated emission computed tomography (NSECT) is presented as a new technique for in vivo tomographic spectroscopic imaging. A full implementation of NSECT is intended to provide an elemental spectrum of the body or part of the body being interrogated at each voxel of a three-dimensional computed tomographic image. An external neutron beam illuminates the sample and some of these neutrons scatter inelastically, producing characteristic gamma emission from the scattering nuclei. These characteristic gamma rays are acquired by a gamma spectrometer and the emitting nucleus is identified by the emitted gamma energy. The neutron beam is scanned over the body in a geometry that allows for tomographic reconstruction. Tomographic images of each element in the spectrum can be reconstructed to represent the spatial distribution of elements within the sample. Here we offer proof of concept for the NSECT method, present the first single projection spectra acquired from multi-element phantoms, and discuss potential biomedical applications.

  7. An investigation of a noninvasive detector system for [oxygen-15]water blood flow studies in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Aykac, Mehmet

    Imaging studies that use positron emission tomography (PET) with [O-15]water have been central for the assessment of neurophysiological activity. Estimation of regional cerebral blood flow (rCBF) for accurate and quantitative mapping of brain function requires measurement of the post-injection arterial time course of [O-15]water. The overall purpose of this work is to design and build a small inexpensive single ring PET tomograph that can be placed around a subject's neck or wrist to noninvasively measure the arterial radioactivity input function. The design and construction of a noninvasive blood sampling system required modeling of the time varying radioactivity distribution in the neck and wrist, examination of the light collection properties of various reflectors and scintillator surface treatment, and an investigation of scintillator size and PMT coupling. Neural network method was also used in order to estimate phenomenologically the light collection efficiency of the coincidence detectors. Two detector modules were designed and fabricated using 0.8mm x 10mm x 20mm BGO crystals wrapped with Teflon reflector of 0.1 mm thickness and coupled to R5900-L16 PSPMTs (Hamamatsu, Japan). A coincidence detector system with 184mm ring diameter was simulated by Monte Carlo methods and experimental data acquired by rotating the radioactive phantoms in front of two detector modules operated in coincidence. Detector linearity was verified up to 125mCi/ml radioactivity concentration. The sensitivity of the system was extrapolated to be 1600 (counts/sec)/(mCi/ml) for 578 total detectors of an equivalent ring tomograph. The spatial resolution of the system was measured <=2mm. The system responded linearly to bolus injections between 50mCi and 375mCi. Due to the small field of view (7mm), the system was not tested in the clinical operation. Inter-crystal scattering of the annihilation photons and transmission of scintillation photons limit energy resolution. Improvements in

  8. 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.

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

    PubMed

    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.

  10. 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.

  11. Positron emission tomography and computed tomography assessments of the aging human brain

    SciTech Connect

    de Leon, M.J.; George, A.E.; Ferris, S.H.; Christman, D.R.; Fowler, J.S.; Gentes, C.I.; Brodie, J.; Reisberg, B.; Wolf, A.P.

    1984-02-01

    The relationship between alterations in brain structure and brain function was studied in vivo in both young and elderly human subjects. Computed tomography revealed significant age-related ventricular and cortical sulcal dilatation. The cortical changes were most closely related to age. Positron emission tomography failed to show regional changes in brain glucose metabolic rate. The results suggest that the normal aging brain undergoes structural atrophic changes without incurring regional metabolic changes. Examination of the correlations between the structural and the metabolic measures revealed no significant relationships. These data are discussed with respect to the significant structure-function relationships that have been reported in Alzheimer disease. 27 references, 3 figures, 2 tables.

  12. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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.

  17. 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.

  18. Tumor Quantification in Clinical Positron Emission Tomography

    PubMed Central

    Bai, Bing; Bading, James; Conti, Peter S

    2013-01-01

    Positron emission tomography (PET) is used extensively in clinical oncology for tumor detection, staging and therapy response assessment. Quantitative measurements of tumor uptake, usually in the form of standardized uptake values (SUVs), have enhanced or replaced qualitative interpretation. In this paper we review the current status of tumor quantification methods and their applications to clinical oncology. Factors that impede quantitative assessment and limit its accuracy and reproducibility are summarized, with special emphasis on SUV analysis. We describe current efforts to improve the accuracy of tumor uptake measurements, characterize overall metabolic tumor burden and heterogeneity of tumor uptake, and account for the effects of image noise. We also summarize recent developments in PET instrumentation and image reconstruction and their impact on tumor quantification. Finally, we offer our assessment of the current development needs in PET tumor quantification, including practical techniques for fully quantitative, pharmacokinetic measurements. PMID:24312151

  19. Imaging tumour hypoxia with positron emission tomography

    PubMed Central

    Fleming, I N; Manavaki, R; Blower, P J; West, C; Williams, K J; Harris, A L; Domarkas, J; Lord, S; Baldry, C; Gilbert, F J

    2015-01-01

    Hypoxia, a hallmark of most solid tumours, is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. Given its prominent role in oncology, accurate detection of hypoxia is important, as it impacts on prognosis and could influence treatment planning. A variety of approaches have been explored over the years for detecting and monitoring changes in hypoxia in tumours, including biological markers and noninvasive imaging techniques. Positron emission tomography (PET) is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. This review provides an overview of imaging hypoxia with PET, with an emphasis on the advantages and limitations of the currently available hypoxia radiotracers. PMID:25514380

  20. Positron emission tomography and single-photon emission computed tomography in substance abuse research.

    PubMed

    Volkow, Nora D; Fowler, Joanna S; Wang, Gene-Jack

    2003-04-01

    Many advances in the conceptualization of addiction as a disease of the brain have come from the application of imaging technologies directly in the human drug abuser. New knowledge has been driven by advances in radiotracer design and chemistry and positron emission tomography (PET) and single-photon emission computed tomography (SPECT) instrumentation and the integration of these scientific tools with the tools of biochemistry, pharmacology, and medicine. This topic cuts across the medical specialties of neurology, psychiatry, oncology, and cardiology because of the high medical, social, and economic toll that drugs of abuse, including the legal drugs, cigarettes and alcohol, take on society. This article highlights recent advances in the use of PET and SPECT imaging to measure the pharmacokinetic and pharmacodynamic effects of drugs of abuse on the human brain.

  1. Calorimetry in Medical Applications: Single-Photon Emission Computed Tomography and Positron Emission Tomography

    SciTech Connect

    Chen, C.-T.

    2006-10-27

    Positron emission tomography (PET) and single-photon emission computed tomography (SPECT), two nuclear medicine imaging modalities broadly used in clinics and research, share many common instrumentation, detector, and electronics technology platforms with calorimetry in high-energy physics, astronomy, and other physics sciences. Historically, advances made in calorimetry had played major roles in the development of novel approaches and critical technologies essential to the evolution of PET and SPECT. There have also been examples in which PET/SPECT developments had led to new techniques in calorimetry for other application areas. In recent years, several innovations have propelled advances in both calorimetry in general and PET/SPECT in particular. Examples include time-of-flight (TOF) measurements, silicon photomultipliers (SiPMs), etc.

  2. 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.

  3. 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.

  4. Cluster analysis for identifying sub-types of tinnitus: a positron emission tomography and voxel-based morphometry study.

    PubMed

    Schecklmann, Martin; Lehner, Astrid; Poeppl, Timm B; Kreuzer, Peter M; Hajak, Göran; Landgrebe, Michael; Langguth, Berthold

    2012-11-16

    Tinnitus is a heterogeneous disorder with respect to its etiology and phenotype. Thus, the identification of sub-types implicates high relevance for treatment recommendations. For this aim, we used cluster analysis of patients for which clinical data, positron-emission tomography (PET) data and voxel-based morphometry (VBM) data were available. 44 patients with chronic tinnitus were included in this analysis. On a phenotypical level, we used tinnitus distress, duration, and laterality for clustering. To correct PET and VBM data for age, gender, and hearing, we built up a design matrix including these variables as regressors and extracted the residuals. We applied Ward's clustering method and forced cluster analysis to divide the data into two groups for both imaging and phenotypical data. On a phenotypical level the clustered groups differed only in tinnitus laterality (uni- vs. bilateral tinnitus), but not in tinnitus duration, distress, age, gender, and hearing. For grey matter volume, groups differed mainly in frontal, cingulate, temporal, and thalamic areas. For glucose metabolism, groups differed in temporal and parietal areas. The correspondence of classification was near chance level for the interrelationship of all three data set clusters. Thus, we showed that clustering according to imaging data is feasible and might depict a new approach for identifying tinnitus sub-types. However, it remains an open question to what extent the phenotypical and imaging levels may be interrelated. This article is part of a Special Issue entitled: Tinnitus Neuroscience.

  5. Use of fuzzy edge single-photon emission computed tomography analysis in definite Alzheimer's disease - a retrospective study

    PubMed Central

    2010-01-01

    Background Definite Alzheimer's disease (AD) requires neuropathological confirmation. Single-photon emission computed tomography (SPECT) may enhance diagnostic accuracy, but due to restricted sensitivity and specificity, the role of SPECT is largely limited with regard to this purpose. Methods We propose a new method of SPECT data analysis. The method is based on a combination of parietal lobe selection (as regions-of-interest (ROI)), 3D fuzzy edge detection, and 3D watershed transformation. We applied the algorithm to three-dimensional SPECT images of human brains and compared the number of watershed regions inside the ROI between AD patients and controls. The Student's two-sample t-test was used for testing domain number equity in both groups. Results AD patients had a significantly reduced number of watershed regions compared to controls (p < 0.01). A sensitivity of 94.1% and specificity of 80% was obtained with a threshold value of 57.11 for the watershed domain number. The narrowing of the SPECT analysis to parietal regions leads to a substantial increase in both sensitivity and specificity. Conclusions Our non-invasive, relatively low-cost, and easy method can contribute to a more precise diagnosis of AD. PMID:20809946

  6. Aspects of the application of positron emission tomography to engineering studies: Drawing overlays and correction for photon attenuation

    NASA Astrophysics Data System (ADS)

    O'Dwyer, M. A.; Hawkesworth, M. R.; Walker, J.

    1988-12-01

    Two important aspects of the application of positron emission tomography in engineering are: the creation of accurate but simplified engineering drawings to overlay the radiolabel tomograms as an aid to their interpretation, and the correction of important features in tomograms for attenuation in overlying metal to provide quantitative information. The practical difficulties met in producing overlays and correcting for attenuation are described, and strategies which are proving useful to overcome them are outlined. The essential starting point is the creation in computer memory of a full three-dimensional representation of all the subject of interest. After scaling, any plane through this model can then be extracted to overlay the appropriate plane through the radiolabel distribution, and all acceptable photon trajectories can be traced from each volume element containing positron emitter to give correction factors for attenuation in the materials traversed. It is shown that it is appropriate to use the total attenuation coefficients of materials in the correction and, finally, a gradient-contour routine is described for separating true signal from background prior to correction.

  7. Effect of subthalamic nucleus stimulation during exercise on the mesolimbocortical dopaminergic region in Parkinson's disease: a positron emission tomography study.

    PubMed

    Nozaki, Takao; Sugiyama, Kenji; Yagi, Shunsuke; Yoshikawa, Etsuji; Kanno, Toshihiko; Asakawa, Tetsuya; Ito, Tae; Terada, Tatsuhiro; Namba, Hiroki; Ouchi, Yasuomi

    2013-03-01

    To elucidate the dynamic effects of deep brain stimulation (DBS) in the subthalamic nucleus (STN) during activity on the dopaminergic system, 12 PD patients who had STN-DBS operations at least 1 month prior, underwent two positron emission tomography scans during right-foot movement in DBS-off and DBS-on conditions. To quantify motor performance changes, the motion speed and mobility angle of the foot at the ankle were measured twice. Estimations of the binding potential of [(11)C]raclopride (BP(ND)) were based on the Logan plot method. Significant motor recovery was found in the DBS-on condition. The STN-DBS during exercise significantly reduced the [(11)C]raclopride BP(ND) in the caudate and the nucleus accumbens (NA), but not in the dorsal or ventral putamen. The magnitude of dopamine release in the NA correlated negatively with the magnitude of motor load, indicating that STN-DBS facilitated motor behavior more smoothly and at less expense to dopamine neurons in the region. The lack of dopamine release in the putamen and the significant dopamine release in the ventromedial striatum by STN-DBS during exercise indicated dopaminergic activation occurring in the motivational circuit during action, suggesting a compensatory functional activation of the motor loop from the nonmotor to the motor loop system.

  8. Teflon laryngeal granuloma presenting as laryngeal cancer on combined positron emission tomography and computed tomography scanning.

    PubMed

    Ondik, M P; Kang, J; Bayerl, M G; Bruno, M; Goldenberg, D

    2009-05-01

    Positron emission tomography with 18F-fluorodeoxyglucose (18FDG) has been increasingly used in the diagnostic investigation of patients with neoplasms of the head and neck. Positron emission tomography and computed tomography have also proven useful for surveillance of thyroid cancers that no longer concentrate radioiodine. However, certain benign or inflammatory lesions can also accumulate 18F-fluorodeoxyglucose and lead to misdiagnosis. We review and discuss the pitfalls of using positron emission tomography and computed tomography for surveillance of thyroid cancer. We present the case of a 48-year-old woman who was diagnosed with a laryngeal neoplasm on integrated positron emission tomography and computed tomography scanning, after a routine ultrasound demonstrated an enlarged thyroid nodule. On physical examination, she had a laryngeal mass overlying an immobile vocal fold. The mass was biopsied and found to harbour a Teflon granuloma. Positron emission tomography positive Teflon granulomas have previously been reported in the nasopharynx and vocal folds, and should be considered in the differential diagnosis of patients who have undergone prior surgery involving Teflon injection. It is important for otolaryngologists and radiologists to recognise potential causes of false positive positron emission tomography and computed tomography findings, including Teflon granulomas.

  9. 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

  10. Development and Operation of a High Resolution Positron Emission Tomography System to Perform Metabolic Studies on Small Animals.

    NASA Astrophysics Data System (ADS)

    Hogan, Matthew John

    A positron emission tomography system designed to perform high resolution imaging of small volumes has been characterized. Two large area planar detectors, used to detect the annihilation gamma rays, formed a large aperture stationary positron camera. The detectors were multiwire proportional chambers coupled to high density lead stack converters. Detector efficiency was 8%. The coincidence resolving time was 500 nsec. The maximum system sensitivity was 60 cps/(mu)Ci for a solid angle of acceptance of 0.74(pi) St. The maximum useful coincidence count rate was 1500 cps and was limited by electronic dead time. Image reconstruction was done by performing a 3-dimensional deconvolution using Fourier transform methods. Noise propagation during reconstruction was minimized by choosing a 'minimum norm' reconstructed image. In the stationary detector system (with a limited angle of acceptance for coincident events) statistical uncertainty in the data limited reconstruction in the direction normal to the detector surfaces. Data from a rotated phantom showed that detector rotation will correct this problem. Resolution was 4 mm in planes parallel to the detectors and (TURN)15 mm in the normal direction. Compton scattering of gamma rays within a source distribution was investigated using both simulated and measured data. Attenuation due to scatter was as high as 60%. For small volume imaging the Compton background was identified and an approximate correction was performed. A semiquantitative blood flow measurement to bone in the leg of a cat using the ('18)F('-) ion was performed. The results were comparable to investigations using more conventional techniques. Qualitative scans using ('18)F labelled deoxy -D-glucose to assess brain glucose metabolism in a rhesus monkey were also performed.

  11. Cardiac rehabilitation improves coronary endothelial function in patients with heart failure due to dilated cardiomyopathy: A positron emission tomography study.

    PubMed

    Legallois, Damien; Belin, Annette; Nesterov, Sergey V; Milliez, Paul; Parienti, J-J; Knuuti, Juhani; Abbas, Ahmed; Tirel, Olivier; Agostini, Denis; Manrique, Alain

    2016-01-01

    Endothelial dysfunction is common in patients with heart failure and is associated with poor clinical outcome. Cardiac rehabilitation is able to enhance peripheral endothelial function but its impact on coronary vasomotion remains unknown. We aimed to evaluate the effect of cardiac rehabilitation on coronary vasomotion in patients with heart failure. We prospectively enrolled 29 clinically stable heart failure patients from non-ischaemic dilated cardiomyopathy and without coronary risk factors. Myocardial blood flow was quantified using (15)-O water positron emission tomography at rest and during a cold pressor test, before and after 12 weeks of cardiac rehabilitation and optimization of medical therapy. Rest myocardial blood flow was significantly improved after the completion of rehabilitation compared to baseline (1.31 ± 0.38 mL/min/g vs. 1.16 ± 0.41 mL/min/g, p = 0.04). The endothelium-related change in myocardial blood flow from rest to cold pressor test and the percentage of myocardial blood flow increase during the cold pressor test were both significantly improved after cardiac rehabilitation (respectively from -0.03 ± 0.22 mL/min/g to 0.19 ± 0.22 mL/min/g, p < 0.001 and from 101.5 ± 16.5% to 118.3 ± 24.4%, p < 0.001). Left ventricular ejection fraction, plasma levels of brain natriuretic peptide, maximal oxygen consumption and the Minnesota Living with Heart Failure Questionnaire score were also significantly improved. The improvement was not related to uptitration of medical therapy. Coronary endothelial function is altered in patients with heart failure due to non-ischaemic dilated cardiomyopathy. In these patients, cardiac rehabilitation significantly improves coronary vasomotion. © The European Society of Cardiology 2014.

  12. Brain areas involved in acupuncture needling sensation of de qi: a single-photon emission computed tomography (SPECT) study.

    PubMed

    Chen, Jia-Rong; Li, Gan-Long; Zhang, Gui-Feng; Huang, Yong; Wang, Shu-Xia; Lu, Na

    2012-12-01

    De qi is a sensory response elicited by acupuncture stimulation. According to traditional Chinese medicine (TCM), de qi is essential for clinical efficacy. However, the understanding of the neurobiological basis of de qi is still limited. To investigate the relationship between brain activation and de qi by taking a single-photon emission computed tomography (SPECT) scan while applying acupuncture at TE5. A total of 24 volunteers were randomly divided into 4 groups, and received verum or sham acupuncture at true acupuncture point TE5 or a nearby sham point according to grouping. All subjects then received a (99m)Tc-ethylcysteinate dimer (ECD) SPECT scan. All six subjects in the verum acupuncture at true acupuncture point group experienced de qi sensation; in contrast, all six subjects in the sham acupuncture at the sham point group responded with nothing other than non-sensation. Compared to the scan results from subjects who experienced non-sensation, SPECT scans from subjects with de qi sensation demonstrated significant activated points mainly located in brodmann areas 6, 8, 19, 21, 28, 33, 35, 37, 47, the parahippocampal gyrus, lentiform nucleus, claustrum and red nucleus; deactivated points were seen in brodmann areas 9 and 25. Verum acupuncture at true acupuncture points is more likely to elicit de qi sensation. De qi sensations mainly resulted in brain area activations, but not deactivations. These brain areas are related to the curative effect of Te5. The acupuncture needle sensations of de qi and sharp pain are associated with different patterns of activations and deactivations in the brain.

  13. Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography.

    PubMed

    Tao, Li; Daghighian, Henry M; Levin, Craig S

    2017-01-01

    We compare the performance of two detector materials, cadmium telluride (CdTe) and bismuth silicon oxide (BSO), for optical property modulation-based radiation detection method for positron emission tomography (PET), which is a potential new direction to dramatically improve the annihilation photon pair coincidence time resolution. We have shown that the induced current flow in the detector crystal resulting from ionizing radiation determines the strength of optical modulation signal. A larger resistivity is favorable for reducing the dark current (noise) in the detector crystal, and thus the higher resistivity BSO crystal has a lower (50% lower on average) noise level than CdTe. The CdTe and BSO crystals can achieve the same sensitivity under laser diode illumination at the same crystal bias voltage condition while the BSO crystal is not as sensitive to 511-keV photons as the CdTe crystal under the same crystal bias voltage. The amplitude of the modulation signal induced by 511-keV photons in BSO crystal is around 30% of that induced in CdTe crystal under the same bias condition. In addition, we have found that the optical modulation strength increases linearly with crystal bias voltage before saturation. The modulation signal with CdTe tends to saturate at bias voltages higher than 1500 V due to its lower resistivity (thus larger dark current) while the modulation signal strength with BSO still increases after 3500 V. Further increasing the bias voltage for BSO could potentially further enhance the modulation strength and thus, the sensitivity.

  14. A positron emission tomography study of short- and long-term treatment effects on functional brain activation in adults who stutter.

    PubMed

    De Nil, Luc F; Kroll, Robert M; Lafaille, Sophie J; Houle, Sylvain

    2003-01-01

    Previous studies have shown that fluency-inducing techniques, such as choral speech, result in changes in neural activation as measured by functional neuroimaging. In the present study, positron emission tomography was used to investigate the effects of intensive behavioural treatment, followed by a 1-year maintenance program, on the pattern of cortical and subcortical activation in stuttering adults during silent and oral reading of single words. The results indicate changes in activation lateralisation, as well as a general reduction in over-activation, especially in the motor cortex, following treatment. The results are discussed in light of previous functional imaging studies with stuttering adults. The reader will learn about and be able to describe the: (1) use of functional neuroimaging PET in the study of stuttering; (2) differences in neural activation between stuttering and non-stuttering adults; and (3) effects of behavioural fluency treatment on cortical and subcortical activations in stuttering speakers.

  15. 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.

  16. 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.

  17. Low Utility of Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography for Detecting Hepatocellular Carcinoma in Patients Before Liver Transplantation.

    PubMed

    Alotaibi, Faisal; Kabbani, Monther; Abaalkhail, Faisal; Chorley, Alicia; Elbeshbeshy, Hany; Al-Hamoudi, Waleed; Alabbad, Saleh; Boehnert, Markus U; Alsofayan, Mohammad; Al-Kattan, Wael; Ahmed, Baderaldeen; Broering, Dieter; Al Sebayel, Mohamed; Elsiesy, Hussien

    2017-02-01

    Our program routinely used fluorodeoxyglucose-positron emission tomography/computed tomography as part of the liver transplant evaluation of patients with hepatocellular carcinoma. The aim of this study was to evaluate the role of this imaging modality in the pretransplant work-up. This was a retrospective chart review of our liver transplant database from January 2011 to December 2014 for all patients with hepatocellular carcinoma who underwent a liver transplant. Collected data included age, sex, cause of liver disease, imaging modality, fluorodeoxyglucose-positron emission tomography/computed tomography results, explant tissue analysis, type of transplant, and transplant outcome. During the study period, 275 liver transplants were performed. Fifty-three patients had hepatocellular carcinoma; 41 underwent fluorodeoxyglucose-positron emission tomography/computed tomography. Twenty-nine patients underwent living-donor liver transplant, and 12 patients underwent deceased-donor liver transplant. One of the 41 patients with negative FDG-imaging results had no evidence of hepatocellular carcinoma in the explant and was excluded from the study. The patients' average age was 58 years (range, 22-72 y), and 28 patients were men. The cause of liver disease was hepatitis C virus in 24 patients, cryptogenic cirrhosis in 12 patients, and hepatitis B virus in 5 patients. One patient had no hepatocellular carcinoma on explants and was excluded from the study. Twenty-five patients had hepatocellular carcinoma that met the Milan criteria, 7 were within the UCSF (University of California, San Francisco) criteria, and 8 exceeded the UCSF criteria. Of the 40 patients, 11 had positive fluorodeoxyglucose-positron emission tomography/computed tomography results (27.5%) with evidence of hepatocellular carcinoma in the explant; the remaining 29 patients (72.5%) had negative results. The fluorodeoxyglucose-positron emission tomography/computed tomography results were positive in 16% (4 of

  18. 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

  19. Single photon emission computerized tomography and histological evaluation in the validation of a new technique for closure of oro-antral communication: an experimental study in pigs.

    PubMed

    Ogunsalu, C O; Rohrer, M; Persad, Hari; Archibald, A; Watkins, J; Daisley, H; Ezeokoli, C; Adogwa, A; Legall, C; Khan, O

    2008-03-01

    Various bone regeneration techniques have evolved recently but controversies regarding vascularization and integration of such bone grafting techniques have led occasionally to animal experiment to validate such techniques. The objective of this study was to evaluate the evidence of vascularization and osseo-integration of a new bone regeneration technique utilized for the closure of oro-antral communication (OAC) by an experimental model in which Single Photon Emission computerized Tomography and histological studies were conducted in pigs. We conclude that the sandwich technique used for the closure of OAC results in a vascularized new bone formation which eventually osseo-integrate with the surrounding bone. Also, this experimental study confirmed that autogeneous bone graft was superior to xenografts when used within the sandwich unit.

  20. SPECT (Single-Photon Emission Computerized Tomography) Scan

    MedlinePlus

    SPECT scan Overview By Mayo Clinic Staff A single-photon emission computerized tomography (SPECT) scan lets your doctor analyze the function of some of your internal organs. A SPECT scan is a type of nuclear imaging test, ...

  1. Binding of Pramipexole to Extrastriatal Dopamine D2/D3 Receptors in the Human Brain: A Positron Emission Tomography Study Using 11C-FLB 457

    PubMed Central

    Ishibashi, Kenji; Ishii, Kenji; Oda, Keiichi; Mizusawa, Hidehiro; Ishiwata, Kiichi

    2011-01-01

    The purpose of this study was to determine the binding sites of pramipexole in extrastriatal dopaminergic regions because its antidepressive effects have been speculated to occur by activating the dopamine D2 receptor subfamily in extrastriatal areas. Dynamic positron emission tomography (PET) scanning using 11C-FLB 457 for quantification of D2/D3 receptor subtype was performed on 15 healthy volunteers. Each subject underwent two PET scans before and after receiving a single dose of pramipexole (0, 0.125, or 0.25 mg). The study demonstrated that pramipexole significantly binds to D2/D3 receptors in the prefrontal cortex, amygdala, and medial and lateral thalamus at a dose of 0.25 mg. These regions have been indicated to have some relation to depression and may be part of the target sites where pramipexole exerts its antidepressive effects. PMID:21408026

  2. 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

  3. 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.

  4. 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.

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

    PubMed

    Palmqvist, Sebastian; Mattsson, Niklas; Hansson, Oskar

    2016-04-01

    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 (18)F-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 adjustments of different factors and when using different cut-offs for amyloid-β abnormality

  6. Evaluation of 18-F-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) as a staging and monitoring tool for dogs with stage-2 splenic hemangiosarcoma – A pilot study

    PubMed Central

    Winter, Amber L.; Stuebner, Kathleen; Scott, Ruth; Ober, Christopher P.; Anderson, Kari L.; Feeney, Daniel A.; Vallera, Daniel A.; Koopmeiners, Joseph S.; Modiano, Jaime F.; Froelich, Jerry

    2017-01-01

    Positron Emission Tomography-Computed Tomography (PET-CT) is routinely used for staging and monitoring of human cancer patients and is becoming increasingly available in veterinary medicine. In this study, 18-fluorodeoxyglucose (18FDG)-PET-CT was used in dogs with naturally occurring splenic hemangiosarcoma (HSA) to assess its utility as a staging and monitoring modality as compared to standard radiography and ultrasonography. Nine dogs with stage-2 HSA underwent 18FDG-PET-CT following splenectomy and prior to commencement of chemotherapy. Routine staging (thoracic radiography and abdominal ultrasonography) was performed prior to 18FDG-PET-CT in all dogs. When abnormalities not identified on routine tests were noted on 18FDG-PET-CT, owners were given the option to repeat a PET-CT following treatment with eBAT. A PET-CT scan was repeated on Day 21 in three dogs. Abnormalities not observed on conventional staging tools, and most consistent with malignant disease based on location, appearance, and outcome, were detected in two dogs and included a right atrial mass and a hepatic nodule, respectively. These lesions were larger and had higher metabolic activity on the second scans. 18FDG-PET-CT has potential to provide important prognostic information and influence treatment recommendations for dogs with stage-2 HSA. Additional studies will be needed to precisely define the value of this imaging tool for staging and therapy monitoring in dogs with this and other cancers. PMID:28222142

  7. 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

  8. 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.

  9. 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

  10. Reversal of focal "misery-perfusion syndrome" by extra-intracranial arterial bypass in hemodynamic cerebral ischemia. A case study with 15O positron emission tomography.

    PubMed

    Baron, J C; Bousser, M G; Rey, A; Guillard, A; Comar, D; Castaigne, P

    1981-01-01

    Tomographic images of cerebral blood flow (CBF) and oxygen extraction fraction (OEF) using the 15O continuous inhalation technique, and positron emission tomography, were obtained from a patient with cerebral ischemia distal to an occluded left internal carotid artery. There was a focal mismatch between CBF and oxygen metabolism in the brain supplied by the middle cerebral artery where CBF was decreased and OEF increased ("misery-perfusion syndrome" as opposed to "luxury-perfusion syndrome"). These abnormalities were most marked in the parieto-occipital watershed area. After left superficial temporal to middle cerebral artery anastomosis, the clinical attacks ceased and a repeat study did not demonstrate the previous CBF and OEF abnormalities. This suggests that this pattern of abnormalities indicates potential viable tissue. The concept of "misery-perfusion" may be of some importance in the pathophysiological mechanisms of hemodynamic cerebral ischemia and serve as a rational basis for revascularization procedures.

  11. 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.

  12. Asymptomatic Emphysematous Pyelonephritis - Positron Emission Tomography Computerized Tomography Aided Diagnostic and Therapeutic Elucidation

    PubMed Central

    Pathapati, Deepti; Shinkar, Pawan Gulabrao; kumar, Satya Awadhesh; Jha; Dattatreya, Palanki Satya; Chigurupati, Namrata; Chigurupati, Mohana Vamsy; Rao, Vatturi Venkata Satya Prabhakar

    2017-01-01

    The authors report an interesting coincidental unearthing by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of a potentially serious medical condition of emphysematous pyelonephritis in a case of nasopharyngeal carcinoma. The management by conservative ureteric stenting and antibiotics was done with gratifying clinical outcome. PMID:28242985

  13. 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.

  14. The role of positron emission tomography/computed tomography in planning radiotherapy in endometrial cancer.

    PubMed

    Simcock, Bryony; Narayan, Kailash; Drummond, Elizabeth; Bernshaw, David; Wells, Elizabeth; Hicks, Rodney J

    2015-05-01

    The optimal method of assessing disease distribution in endometrial cancer is widely debated. Knowledge of disease distribution assists in planning adjuvant radiotherapy; in this study we used positron emission tomography/computed tomography (PET/CT) to assess disease distribution before radiotherapy. Seventy-three consecutive patients referred to the Peter MacCallum Cancer Centre for adjuvant radiotherapy for endometrial cancer, with either high-risk disease after a hysterectomy or recurrent disease, had a PET/CT before treatment. The findings on PET/CT and clinical course were recorded. PET/CT found additional disease in 35% of postoperative patients, changing planned treatment in 31%. In the group with known recurrence, additional disease was found in 72%, changing management in 36%. PET/CT is a valuable tool for planning radiotherapy in endometrial cancer.

  15. Incorporation of Time-of-Flight Information Reduces Metal Artifacts in Simultaneous Positron Emission Tomography/Magnetic Resonance Imaging: A Simulation Study.

    PubMed

    Davison, Helen; ter Voert, Edwin E G W; de Galiza Barbosa, Felipe; Veit-Haibach, Patrick; Delso, Gaspar

    2015-07-01

    This study aimed to describe and evaluate the influence of time-of-flight (TOF) information on metal artifact reduction in positron emission tomography (PET) image quality in clinical simultaneous PET/magnetic resonance (MR) scanning. A total of 7 patients with various malignant tumors were included and underwent a PET/MR examination after standard PET/computed tomography. Baseline TOF and non-TOF PET images were reconstructed. Next, the TOF and non-TOF PET reconstructions were repeated after the introduction of artificial signal voids in the attenuation map to simulate metal artifacts of various sizes in a range of locations. Three different sizes of signal voids were inserted in the attenuation maps for each location of interest: over the maxilla, humeral head, chest, sternum, thoracic and lumbar spine, as well as the femoral head to replicate clinically relevant metal artifacts. The reconstructed images with the artifacts were then compared with the baseline reconstructed images. The mean percentage error in a region of interest surrounding the simulated artifact was used to compare between TOF and non-TOF images. Further comparison between TOF and non-TOF images was performed using histogram analysis. In all cases, the mean percentage error in a region of interest surrounding the simulated artifact was reduced when TOF information was included in the reconstruction. The inclusion of TOF also changes the distribution of smaller errors away from the origin of the artifact. In some anatomical regions, an increase in the number of small errors was noted with TOF, although the differences with non-TOF were minimal. Positron emission tomographic imaging benefits from the integration of TOF information in simultaneous PET/MR. The inclusion of TOF information in simultaneous PET/MR imaging reduces errors related to metal artifacts at the site of the artifact.

  16. Influence of 24-Nor-Ursodeoxycholic Acid on Hepatic Disposition of [(18)F]Ciprofloxacin, a Positron Emission Tomography Study in Mice.

    PubMed

    Wanek, Thomas; Halilbasic, Emina; Visentin, Michele; Mairinger, Severin; Römermann, Kerstin; Stieger, Bruno; Kuntner, Claudia; Müller, Markus; Langer, Oliver; Trauner, Michael

    2016-01-01

    24-nor-ursodeoxycholic acid (norUDCA) is a novel therapeutic approach to cholestatic liver diseases. In mouse models of cholestasis, norUDCA induces basolateral multidrug resistance-associated proteins 4 (Mrp4) and 3 in hepatocytes, which provide alternative escape routes for bile acids accumulating during cholestasis but could also result in altered hepatic disposition of concomitantly administered substrate drugs. We used positron emission tomography imaging to study the influence of norUDCA on hepatic disposition of the model Mrp4 substrate [(18)F]ciprofloxacin in wild-type and Mdr2((-/-)) mice, a model of cholestasis. Animals underwent [(18)F]ciprofloxacin positron emission tomography at baseline and after norUDCA treatment. After norUDCA treatment, liver-to-blood area under the curve ratio of [(18)F]ciprofloxacin was significantly decreased compared to baseline, both in wild-type (-34.0 ± 2.1%) and Mdr2((-/-)) mice (-20.5 ± 6.0%). [(18)F]Ciprofloxacin uptake clearance from blood into liver was reduced by -17.1 ± 9.0% in wild-type and by -20.1 ± 7.3% in Mdr2((-/-)) mice. Real-time PCR analysis showed significant increases in hepatic Mrp4 and multidrug resistance-associated protein 3 mRNA after norUDCA. Transport experiments in organic anion transporting polypeptide (OATP)1B1-, OATP1B3-, and OATP2B1-transfected cells revealed weak transport of [(14)C]ciprofloxacin by OATP1B3 and OATP2B1 and no inhibition by norUDCA. In conclusion, our data suggest that changes in hepatic [(18)F]ciprofloxacin disposition in mice after norUDCA treatment were caused by induction of basolateral Mrp4 in hepatocytes.

  17. Early and late stage positron emission tomography (PET) studies on the haemocirculation and metabolism of seemingly normal brain tissue in patients with gliomas following radiochemotherapy.

    PubMed

    Mineura, K; Suda, Y; Yasuda, T; Kowada, M; Ogawa, T; Shishido, F; Uemura, K

    1988-01-01

    Haemocirculatory and metabolic changes in seemingly normal brain tissue following radiochemotherapy including nimustine hydrochloride (ACNU) and tegafur (FT) were analyzed using oxygen-15 and fluorine-18 positron emission tomography (PET) in seven patients with gliomas. At an early stage (within one month) after radiochemotherapy, marginal increases in regional cerebral blood flow (rCBF) and cerebral blood volume (rCBV) were found contralateral to the tumour in gray matter which was apparently normal brain structure, as seen on computerized tomography (CT). The oxygen extraction fraction (rOEF) decreased significantly (p less than 0.05 by a paired-t test) from that of the pretreatment study, due to surgical decompression and radiochemotherapy. At the late stage (three to thirty-one months with a mean of thirteen months), rCBF decreased significantly from the early stage study (p less than 0.05); oxygen consumption (rCMRO2) fell in all cases significantly from the pretreatment study (p less than 0.01) and from the early stage study (p less than 0.05); consequently, rOEF remained unchanged at a level similar to the early stage study. Glucose consumption (rCMRG1) increased slightly as compared with the early stage study but failed to be restored to the level of the pretreatment study. Noteworthy was a coupling reduction of rCBF and rCMRO2--presumably, a late delayed effect of radiochemotherapy. These preliminary results indicate that with PET studies it may be possible to predict damage to normal brain tissue after radiochemotherapy.

  18. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1200 Emission computed...

  19. Validation of left ventricular function from gated single photon computed emission tomography by using a scintillator-photodiode camera: a dynamic myocardial phantom study.

    PubMed

    Kubo, N; Mabuchi, M; Katoh, C; Arai, H; Morita, K; Tsukamoto, E; Morita, Y; Tamaki, N

    2002-07-01

    A scintillator-photodiode camera is able to acquire single photon emission computed tomography (SPECT) images by using a rotating chair system. We validated the left ventricular (LV) parameters of this camera system utilizing a dynamic myocardial phantom. Gated myocardial SPECT of a dynamic myocardial phantom (Hokkaido University type; end diastolic volume (EDV), 143 ml; end systolic volume (ESV), 107 ml; ejection fraction (EF), 25%) was performed with this scintillation camera. LV parameters were calculated using pre-installed software (Mirage Myocardial Perfusion SPECT) (study 1) and the other software (QGS; Cedars-Sinai) (study 2). For comparison, SPECT from a traditional Anger camera were processed by the QGS software (study 3). The estimated volumes were similar among the three studies (EDV, 110+/-8 ml in study 1, 112+/-2 ml in study 2 and 111+/-1 ml in study 3; ESV, 86+/-8 ml in study 1, 93+/-4 ml in study 2 and 91+/-2 ml in study 3). The estimated EFs were 23+/-3%, 17+/-2%, and 18+/-1%, respectively. The calculated volume within each study was underestimated by approximately the same degree. However, each estimated EF value for each study was close to the actual value. The estimated LV function using the scintillator-photodiode camera system may be considered as a suitable alternative to the traditional Anger camera system.

  20. 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.

  1. Positron emission tomography with fluorodeoxyglucose to evaluate tumor response and control after radiation therapy

    SciTech Connect

    Chaiken, L.; Juillard, G.; Rege, S.; Hoh, C.; Choi, Y.; Jabour, B.; Hawkins, R.; Parker, R. )

    1993-09-20

    Following radiation therapy, evaluation of viable tumor can often be difficult with anatomic imaging criteria (tumor size alone). In this study, the utility of biochemical imaging with the glucose analog 2-[F-18]fluoro-2-deoxy-D-glucose and positron emission tomography was investigated in patients with radiation therapy. Post-radiation positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose studies were done in all patients, with 9 head and neck patients receiving pre-radiation positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose scans as well. Results were correlated with other imaging techniques and pathology. Positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose detected head and neck primary tumors and lymph node metastases in all nine pre-radiation scans, while magnetic resonance imaging failed to detect two primary tumors. Serial positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose showed a significant decrease in tumor activity after radiation therapy, compared to pre-radiation levels, (p < 0.05), except for two patients with increased uptake at the primary site. Biopsies of these two patients showed persistent/recurrent disease after radiation therapy, which was not detected by magnetic resonance imaging. Six additional head and neck patients, with suspicious examination and inconclusive magnetic resonance imaging, were imaged with positron emission tomography after radiation therapy only. Five patients had increased positron emission tomography activity, with corresponding biopsies positive in four patients, and negative in one patient with clinically worsening symptoms. The remaining sixth patient had minimal and stable positron emission tomography uptake, and is improving clinically. Four patients had mammogram findings suspicious for recurrence after conservation treatment for breast cancer. 40 refs., 6 figs., 1 tab.

  2. Shifted helical computed tomography to optimize cardiac positron emission tomography-computed tomography coregistration: quantitative improvement and limitations.

    PubMed

    Johnson, Nils P; Pan, Tinsu; Gould, K Lance

    2010-10-01

    Positron emission tomography-computed tomography (PET-CT) uses CT attenuation correction but suffers from misregistration artifacts. However, the quantitative accuracy of helical versus cine CT in the same patient after optimized coregistration by shifting both CT data as needed for each patient is unknown. We studied 293 patients undergoing cardiac perfusion PET-CT using helical CT attenuation correction for comparison to cine CT. Objective, quantitative criteria identified perfusion abnormalities that were associated visually with PET-CT misregistration. Custom software shifted CT data to optimize coregistration with quantitative artifact improvement. The majority (58.1%) of cases with both helical and shifted helical CT data (n  = 93) had artifacts that improved or resolved by software shifting helical CT data. Translation of shifted helical CT was greatest in the x-direction (8.8 ± 3.3 mm) and less in the y- and z-directions (approximately 3.5 mm). The magnitude of differences in quantitative end points was greatest for helical (p  =  .0001, n  =  177 studies), less for shifted helical but significant (p  =  .0001, n  =  93 studies), and least for cine (not significant, n  =  161 studies) CT compared to optimal attenuation correction for each patient. Frequent artifacts owing to attenuation-emission misregistration are substantially corrected by software shifting helical CT scans to achieve proper coregistration that, however, remains on average significantly inferior to cine CT attenuation quantitatively.

  3. Systemic and vascular inflammation in patients with moderate to severe psoriasis as measured by [18F]-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT): a pilot study.

    PubMed

    Mehta, Nehal N; Yu, YiDing; Saboury, Babak; Foroughi, Negar; Krishnamoorthy, Parasuram; Raper, Anna; Baer, Amanda; Antigua, Jules; Van Voorhees, Abby S; Torigian, Drew A; Alavi, Abass; Gelfand, Joel M

    2011-09-01

    To evaluate the feasibility of using [18F]-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) to detect and quantify systemic inflammation in patients with psoriasis. Case series with a nested case-control study. Referral dermatology and preventive cardiology practices. Six patients with psoriasis affecting more than 10% of their body surface area and 4 controls age and sex matched to 4 of the patients with psoriasis for a nested case-control study. The FDG uptake in the liver, musculoskeletal structures, and aorta measured by mean standardized uptake value, a measure of FDG tracer uptake by macrophages and other inflammatory cells. FDG-PET/CT identified numerous foci of inflammation in 6 patients with psoriasis within the skin, liver, joints, tendons, and aorta. Inflammation in the joints was observed in a patient with psoriatic arthritis as well as in 1 patient with no history of joint disease or joint symptoms. In a nested case-control study, FDG-PET/CT imaging demonstrated increased vascular inflammation in multiple segments of the aorta compared with controls. These findings persisted after adjustment for traditional cardiovascular risk factors in multivariate analysis (mean β = 0.33; P < .001). Patients with psoriasis further demonstrated increased hepatic inflammation after adjusting for cardiovascular risk factors (β = 0.18; P < .001), but the association was no longer significant when adjusted for alcohol intake (β = -0.25; P = .07). FDG-PET/CT is a sensitive tool for identifying inflammation and can be used to identify clinically observed inflammation in the skin and subclinical inflammation in the blood vessels, joints, and liver of patients with psoriasis.

  4. Monte Carlo Simulation Of Emission Tomography And Other Medical Imaging Techniques.

    PubMed

    Harrison, Robert L

    2010-01-05

    An introduction to Monte Carlo simulation of emission tomography. This paper reviews the history and principles of Monte Carlo simulation, then applies these principles to emission tomography using the public domain simulation package SimSET (a Simulation System for Emission Tomography) as an example. Finally, the paper discusses how the methods are modified for X-ray computed tomography and radiotherapy simulations.

  5. Single-photon emission computed tomography/computed tomography in brain tumors.

    PubMed

    Schillaci, Orazio; Filippi, Luca; Manni, Carlo; Santoni, Riccardo

    2007-01-01

    Anatomic imaging procedures (computed tomography [CT] and magnetic resonance imaging [MRI]) have become essential tools for brain tumor assessment. Functional images (positron emission tomography [PET] and single-photon emission computed tomography [SPECT]) can provide additional information useful during the diagnostic workup to determine the degree of malignancy and as a substitute or guide for biopsy. After surgery and/or radiotherapy, nuclear medicine examinations are essential to assess persistence of tumor, to differentiate recurrence from radiation necrosis and gliosis, and to monitor the disease. The combination of functional images with anatomic ones is of the utmost importance for a full evaluation of these patients, which can be obtained by means of imaging fusion. Despite the fast-growing diffusion of PET, in most cases of brain tumors, SPECT studies are adequate and provide results that parallel those obtained with PET. The main limitation of SPECT imaging with brain tumor-seeking radiopharmaceuticals is the lack of precise anatomic details; this drawback is overcome by the fusion with morphological studies that provide an anatomic map to scintigraphic data. In the past, software-based fusion of independently performed SPECT and CT or MRI demonstrated usefulness for brain tumor assessment, but this process is often time consuming and not practical for everyday nuclear medicine studies. The recent development of dual-modality integrated imaging systems, which allow the acquisition of SPECT and CT images in the same scanning session, and their co-registration by means of the hardware, has facilitated this process. In SPECT studies of brain tumors with various radiopharmaceuticals, fused images are helpful in providing the precise localization of neoplastic lesions, and in excluding the disease in sites of physiologic tracer uptake. This information is useful for optimizing diagnosis, therapy monitoring, and radiotherapy treatment planning, with a

  6. A case of skeletal tuberculosis and psoas abscess: disease activity evaluated using 18 F-fluorodeoxyglucose positron emission tomography-computed tomography

    PubMed Central

    2013-01-01

    Background Psoas abscess complicating tuberculous spondylitis is a rare morbidity in extrapulmonary tuberculosis. There are no established guidelines for evaluating the clinical response of psoas abscess. Although several studies have shown that positron emission tomography-computed tomography with 18 F-fluorodeoxyglucose can play a potential role in diagnosing multifocal tuberculosis and monitoring the clinical response of pulmonary tuberculosis, to our knowledge, this is the first report demonstrating that positron emission tomography-computed tomography is useful for evaluating local inflammation and disease activity of a tuberculous psoas abscess. Case presentation We report a case of multifocal bone and lymph node tuberculosis with concomitant lumbar psoas abscess in a 77-year-old man, along with a literature review. An initial positron emission tomography-computed tomography scan showed intense 18 F-fluorodeoxyglucose accumulation in the sternum, ribs, vertebrae, and lymph nodes. The patient was successfully treated with antitubercular agents and computed tomography-guided drainage therapy. A follow-up positron emission tomography-computed tomography after abscess drainage and 9 months of antitubercular drug treatment revealed that the majority of lesions improved; however, protracted inflammation surrounding the psoas abscess was still observed. These results indicate that disease activity of psoas abscess can remain, even after successful drainage and antitubercular medication regime of appropriate duration. Conclusion We have successfully followed up the extent of skeletal tuberculosis complicated with psoas abscess by positron emission tomography-computed tomography. In this patient, positron emission tomography-computed tomography is useful for evaluating the disease activity of tuberculous psoas abscess and for assessing the appropriate duration of antitubercular drug therapy in psoas abscess. PMID:24225333

  7. Bone and Gallium Single-Photon Emission Computed Tomography-Computed Tomography is Equivalent to Magnetic Resonance Imaging in the Diagnosis of Infectious Spondylodiscitis: A Retrospective Study.

    PubMed

    Tamm, Alexander S; Abele, Jonathan T

    2017-02-01

    Spondylodiscitis has historically been a difficult clinical diagnosis. Two imaging techniques that address this problem are magnetic resonance imaging (MRI) and combined bone ((99m)Tc-methylene diphosphonate) and gallium-67 single-photon emission computed tomography-computed tomography (SPECT-CT). Their accuracies have not been adequately compared. The purpose of this study is to compare the sensitivities and specificities of bone and gallium SPECT-CT and MRI in infectious spondylodiscitis. This retrospective study assessed all patients who underwent a bone or gallium SPECT-CT of the spine to assess for infectious spondylodiscitis from January 1, 2010, to May 2, 2012, at a single tertiary care centre. Thirty-four patients (23 men; average 62 ± 14 years of age) were included. The results of the bone or gallium SPECT-CT were compared against MRI for all patients in the cohort who underwent an MRI within 12 weeks of the SPECT-CT. A diagnosis of spondylodiscitis in the discharge summary was considered the reference standard, and was based on a combination of clinical scenario, response to therapy, imaging, or microbiology. Spondylodiscitis was diagnosed in 18 patients and excluded in 16. Bone or gallium SPECT-CT and MRI had similar (P > .05; κ = 0.74) sensitivities (0.94 vs 0.94), specificities (1.00 vs 1.00), positive predictive values (1.00 vs 1.00), negative predictive values (0.94 vs 0.80), and accuracies (0.97 vs 0.95) when compared to the reference standard. Although MRI remains the initial modality of choice in diagnosing spondylodiscitis, bone and gallium SPECT-CT appears diagnostically equivalent and should be considered a viable supplementary or alternative imaging modality particularly if there is contraindication or inaccessibility to MRI. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  8. Single photon emission computed tomography/computed tomography for malignant otitis externa: lesion not shown on planar image.

    PubMed

    Chen, Yu-Hung; Hsieh, Hung-Jen

    2013-01-01

    Malignant otitis externa is a severe and rare infection of the external acoustic meatus. Triphasic bone and (67)Ga scintigraphies are used to initial detect and follow-up the response of therapy. With single photon emission computed tomography/computed tomography images, the diagnostic sensitivity is higher. We presented a case with malignant otitis externa with initial negative planar scintigraphic finding. The lesion was detected by photon emission computed tomography/computed tomography images. We concluded that the photon emission computed tomography/computed tomography should be performed routinely for patients with suspected malignant otitis externa, even without evidence of lesion on planar images. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Is there any role of positron emission tomography computed tomography for predicting resectability of gallbladder cancer?

    PubMed

    Kim, Jaihwan; Ryu, Ji Kon; Kim, Chulhan; Paeng, Jin Chul; Kim, Yong-Tae

    2014-05-01

    The role of integrated (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography computed tomography (PET-CT) is uncertain in gallbladder cancer. The aim of this study was to show the role of PET-CT in gallbladder cancer patients. Fifty-three patients with gallbladder cancer underwent preoperative computed tomography (CT) and PET-CT scans. Their medical records were retrospectively reviewed. Twenty-six patients underwent resection. Based on the final outcomes, PET-CT was in good agreement (0.61 to 0.80) with resectability whereas CT was in acceptable agreement (0.41 to 0.60) with resectability. When the diagnostic accuracy of the predictions for resectability was calculated with the ROC curve, the accuracy of PET-CT was higher than that of CT in patients who underwent surgical resection (P=0.03), however, there was no difference with all patients (P=0.12). CT and PET-CT had a discrepancy in assessing curative resection in nine patients. These consisted of two false negative and four false positive CT results (11.3%) and three false negative PET-CT results (5.1%). PET-CT was in good agreement with the final outcomes compared to CT. As a complementary role of PEC-CT to CT, PET-CT tended to show better prediction about resectability than CT, especially due to unexpected distant metastasis.

  10. 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.

  11. 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 Central

    Schwartz, Jill L.; Friend, David R.; Coleman, Jenell S.; Hendrix, Craig W.

    2015-01-01

    Abstract 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 99mtechnetium-DTPA (99mTc) 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 99mTc-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 99mTc-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

  12. Impact of 18F-fluoro-2-deoxyglucose positron emission tomography on treatment strategy and radiotherapy planning for stage I-II Hodgkin disease: a prospective multicenter study.

    PubMed

    Pommier, Pascal; Dussart, Sophie; Girinsky, Théodore; Chabaud, Sylvie; Lagrange, Jean Leon; Nguyen, Tan Dat; Beckendorff, Véronique; D'Hombres, Anne; Artignan, Xavier; Bondiau, Pierre Yves; Carrie, Christian; Giammarile, Francesco

    2011-03-01

    To quantify the impact of preradiotherapy 18F-fluoro-2-deoxyglucose positron-emission tomography (FDG-PET) on treatment strategy and radiotherapy planning for patients with Stage I/II Hodgkin disease included in a large prospective multicenter study. Conventional computed tomography and FDG-PET were performed just before the planned radiotherapy. The radiotherapy plan was first elaborated under blinded conditions for FDG-PET data. Then, the medical staff was asked to confirm or not confirm the treatment strategy and, if appropriate, to modify the radiotherapy plan based on additional information from FDG-PET. Between January 2004 and January 2006, 137 patients were included (124 were available for analysis) in 11 centers (108 adults, 16 children). All but 1 patient had received chemotherapy before inclusion. Prechemotherapy work-up included FDG-PET for 61 patients, and data were available for elaboration of the first radiotherapy plan. Based on preradiotherapy FDG-PET data, the radiotherapy was cancelled in 6 patients (4.8%), and treatment plan modifications occurred in 16 patients (12.9%): total dose (11 patients), CTV volume (5 patients), number of beam incidences (6 patients), and number of CTV (6 patients). The concordance between the treatment strategies with or without preradiotherapy FDG-PET was 82.3%. Concordance results were not significantly different when prechemotherapy PET-CT information was available. Preradiotherapy FDG-PET for treatment planning in Hodgkin lymphoma may lead to significant modification of the treatment strategy and the radiotherapy planning in patients with Stage I or II Hodgkin disease, even in those who have undergone FDG-PET as part of the prechemotherapy work-up. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Impact of 18F-Fluoro-2-Deoxyglucose Positron Emission Tomography on Treatment Strategy and Radiotherapy Planning for Stage I-II Hodgkin Disease: A Prospective Multicenter Study

    SciTech Connect

    Pommier, Pascal; Dussart, Sophie; Girinsky, Theodore; Chabaud, Sylvie; Lagrange, Jean Leon; Nguyen, Tan Dat; Beckendorff, Veronique; D'Hombres, Anne; Artignan, Xavier; Bondiau, Pierre Yves; Carrie, Christian; Giammarile, Francesco

    2011-03-01

    Purpose: To quantify the impact of preradiotherapy 18F-fluoro-2-deoxyglucose positron-emission tomography (FDG-PET) on treatment strategy and radiotherapy planning for patients with Stage I/II Hodgkin disease included in a large prospective multicenter study. Patients and Methods: Conventional computed tomography and FDG-PET were performed just before the planned radiotherapy. The radiotherapy plan was first elaborated under blinded conditions for FDG-PET data. Then, the medical staff was asked to confirm or not confirm the treatment strategy and, if appropriate, to modify the radiotherapy plan based on additional information from FDG-PET. Results: Between January 2004 and January 2006, 137 patients were included (124 were available for analysis) in 11 centers (108 adults, 16 children). All but 1 patient had received chemotherapy before inclusion. Prechemotherapy work-up included FDG-PET for 61 patients, and data were available for elaboration of the first radiotherapy plan. Based on preradiotherapy FDG-PET data, the radiotherapy was cancelled in 6 patients (4.8%), and treatment plan modifications occurred in 16 patients (12.9%): total dose (11 patients), CTV volume (5 patients), number of beam incidences (6 patients), and number of CTV (6 patients). The concordance between the treatment strategies with or without preradiotherapy FDG-PET was 82.3%. Concordance results were not significantly different when prechemotherapy PET-CT information was available. Conclusion: Preradiotherapy FDG-PET for treatment planning in Hodgkin lymphoma may lead to significant modification of the treatment strategy and the radiotherapy planning in patients with Stage I or II Hodgkin disease, even in those who have undergone FDG-PET as part of the prechemotherapy work-up.

  14. Dopamine release in response to a psychological stress in humans and its relationship to early life maternal care: a positron emission tomography study using [11C]raclopride.

    PubMed

    Pruessner, Jens C; Champagne, Frances; Meaney, Michael J; Dagher, Alain

    2004-03-17

    Mesolimbic dopamine is thought to play a role in the processing of rewards. However, animal studies also demonstrate dopamine release in response to aversive stressful stimuli. Also, in animal studies, disruptions of the mother-infant relationship have been shown to have long-lasting effects on the mesolimbic dopamine system and the hypothalamic-pituitary adrenal axis. We therefore investigated dopamine release in response to stress in human subjects, considering the relationship to early life parental care. We screened 120 healthy young college students for parental care in early life using a combination of telephone interviews and questionnaires. Five students from the top end and five students from the bottom end of the parental care distribution were then invited for a positron emission tomography study using [11C]raclopride and a psychosocial stress task. The psychosocial stressor caused a significant release of dopamine in the ventral striatum as indicated by a reduction in [11C]raclopride binding potential in the stress versus resting condition in subjects reporting low parental care. Moreover, the magnitude of the salivary cortisol response to stress was significantly correlated with the reduction in [11C]raclopride binding in the ventral striatum (r = 0.78), consistent with a facilitating effect of cortisol on dopamine neuron firing. These data suggest that aversive stressful events can be associated with mesolimbic dopamine release in humans, and that the method presented here may be useful to study the effects of early life events on neurobiological stress systems.

  15. Breath-hold single-photon emission tomography and computed tomography for predicting residual pulmonary function in patients with lung cancer.

    PubMed

    Sudoh, Manabu; Ueda, Kazuhiro; Kaneda, Yoshikazu; Mitsutaka, Jinbo; Li, Tao-Sheng; Suga, Kazuyoshi; Kawakami, Yasuhiko; Hamano, Kimikazu

    2006-05-01

    We sought to evaluate the utility of integrated breath-hold single-photon emission tomography and computed tomography imaging compared with that of simple calculation with the lung segment-counting technique for predicting residual pulmonary function in patients undergoing surgical intervention for lung cancer. A prospective series of 22 patients undergoing anatomic lung resection for cancer were enrolled in this study. Postoperative residual forced expiratory volume in 1 second was predicted by measuring the radioactivity counts of the affected lobes or segments to be resected within the entire lungs by placement of regions of interest on single-photon emission tomography and computed tomography images. Residual forced expiratory volume in 1 second was also estimated by using the segment-counting technique. Both predicted values agreed well with postoperative forced expiratory volume in 1 second. Although the residual forced expiratory volume in 1 second predicted by means of single-photon emission tomography and computed tomography correlated well with that predicted by using segment counting, the values were significantly underestimated by the segment-counting technique in 4 outliers with severe emphysema. There were 2 patients with borderline pulmonary functional reserve whose residual forced expiratory volume in 1 second values were predicted more accurately by means of single-photon emission tomography and computed tomography than by using segment counting. Integrated breath-hold single-photon emission tomography and computed tomography images allow the accurate prediction of postoperative pulmonary function but without statistical superiority over the simple segment-counting technique. Further study of the usefulness of single-photon emission tomography and computed tomography in patients with severe emphysema and borderline lung function should prove valuable because the segment-counting technique underestimates pulmonary functional reserve in these

  16. The diagnostic possibilities of positron emission tomography (PET): applications in oral and maxillofacial buccal oncology.

    PubMed

    Carranza-Pelegrina, Daniela; Lomeña-Caballero, Francisco; Soler-Peter, Marina; Berini-Aytés, Leonardo; Gay-Escoda, Cosme

    2005-01-01

    The principles of positron emission tomography (PET), recently introduced as a diagnostic procedure into the health sciences, are described. The principle clinical applications apply to a particular group of specialties: cardiology, neurology, psychiatry, and above all oncology. Positron emission tomography is a non-invasive diagnostic imaging technique with clinical applications. It is an excellent tool for the study of the stage and possible malignancy of tumors of head and neck, the detection of otherwise clinically indeterminate metastases and lymphadenopathies, and likewise for the diagnosis of relapses. The only tracer with any practical clinical application is fluor-desoxyglucosa-F18 (FDG). PET detects the intense accumulation of FDG produced in malignant tumors due to the increased glycolytic rate of the neoplastic cells. With the introduction of hybrid systems that combine computerized tomography or magnetic resonance with positron emission tomography, important advances are being made in the diagnosis and follow-up of oncologic pathology of head and neck.

  17. Relation between Dopamine Synthesis Capacity and Cell-Level Structure in Human Striatum: A Multi-Modal Study with Positron Emission Tomography and Diffusion Tensor Imaging

    PubMed Central

    Kawaguchi, Hiroshi; Obata, Takayuki; Takano, Harumasa; Nogami, Tsuyoshi; Suhara, Tetsuya; Ito, Hiroshi

    2014-01-01

    Positron emission tomography (PET) study has shown that dopamine synthesis capacity varied among healthy individuals. This interindividual difference might be due to a difference in the cell-level structure of presynaptic dopaminergic neurons, i.e., cellular density and/or number. In this study, the relations between the dopamine synthesis capacity measured by PET and the parameter estimates in diffusion tensor imaging (DTI) in striatal subregions were investigated in healthy human subjects. DTI and PET studies with carbon-11 labeled L-DOPA were performed in ten healthy subjects. Age-related changes in the above parameters were also considered. Fractional anisotropy showed a significant positive correlation with age in the posterior caudate. There was significant negative correlation between dopamine synthesis capacity and mean diffusivity in the posterior caudate and putamen. Assuming that mean diffusivity reflects the density of wide-spreading axonal terminals in the striatum, the result suggests that dopamine synthesis may be related to the density of dopaminergic neuronal fibers. It is evident that PET/DTI combined measurements can contribute to investigations of the pathophysiology of neuropsychiatric diseases involving malfunction of dopaminergic neurons. PMID:24498218

  18. Receptor binding and selectivity of three 11C-labelled dopamine receptor antagonists in the brain of rhesus monkeys studied with positron emission tomography.

    PubMed

    Hartvig, P; Eckernäs, S A; Ekblom, B; Lindström, L; Lundqvist, H; Axelsson, S; Fasth, K J; Gullberg, P; Långström, B

    1988-04-01

    The regional distribution of 3 11C-labelled dopamine receptor antagonists, N-methyl spiperone, raclopride and clozapine, in the brain of Rhesus monkeys was studied by positron emission tomography (PET). The measured radioactivities in the striatal area were similar for the 3 antagonists, although the highest selectivity as compared to cerebellum was found for 11C-raclopride 60 min after administration. The selectivity of the radiotracers for the serotonin and D2-dopamine receptors was evaluated after pretreatment of the monkeys with serotonin and dopamine receptor antagonists. 11C-N-methylspiperone and 11C-clozapine both bound to serotonin receptors in the frontal cortex and to D2-dopamine receptors in the striatal area. Raclopride was selectively bound to the D2-dopamine receptors. The radioactivities measured in the striatal area with cerebellum as reference were fitted to a 3-compartment model which made possible evaluation of receptor binding characteristics. The rate proportional to the association rate constant for the receptor, kon and number of receptors, Bmax, varied from 0.02-0.07 min-1 between the studied radiolabelled drugs, whereas the apparent dissociation rate was highest for clozapine. This means that clozapine had the lowest affinity for the receptors in the striatum, assuming that the Bmax values are identical. The observed difference in selective receptor binding and binding characteristics of the 3 tracers may have an influence both on the clinical efficacy and side effects of the studied dopamine receptor antagonists.

  19. No regional difference in dopamine D2 receptor occupancy by the second-generation antipsychotic drug risperidone in humans: a positron emission tomography study.

    PubMed

    Ito, Hiroshi; Arakawa, Ryosuke; Takahashi, Hidehiko; Takano, Harumasa; Okumura, Masaki; Otsuka, Tatsui; Ikoma, Yoko; Shidahara, Miho; Suhara, Tetsuya

    2009-06-01

    The effects of antipsychotic drugs have generally been considered to be mediated by blockade of dopamine D2 receptors. The concept of limbic and cortical selectivity of second-generation antipsychotics, i.e. higher dopamine D2 receptor occupancy in the cerebral cortices than in the striatum, has been suggested to explain their clinical efficacy with lower incidence of extrapyramidal side-effects. In this study, regional distribution of dopamine D2 receptor occupancy by risperidone was determined in order to elucidate the limbic and cortical selectivity of second-generation antipsychotics. Striatal and extrastriatal dopamine D2 receptor binding at baseline and after oral administration of 2 mg risperidone were measured in ten healthy men by positron emission tomography (PET) using different tracers with different affinity for the receptors, [11C]raclopride and [11C]FLB 457, respectively. Striatal and extrastriatal occupancies of dopamine D2 receptors were calculated for each brain region. Occupancies of dopamine D2 receptors were about 70% and 60% in the striatum and extrastriatum, respectively. A simulation study showed that non-negligible specific binding in the reference region (cerebellum), could cause systemic underestimation of occupancy in [11C]FLB 457 PET studies, indicating that occupancies in both the striatum and extrastriatum may not have differed. Among the extrastriatal regions including limbic and neocortical regions, no significant regional differences in dopamine D2 receptor occupancy were observed. Thus, limbic and cortical selectivity was not observed by one of the second-generation antipsychotics, risperidone.

  20. Preparation and biodistribution in mice of [11C]carfentanil: a radiopharmaceutical for studying brain mu-opioid receptors by positron emission tomography.

    PubMed

    Saji, H; Tsutsumi, D; Magata, Y; Iida, Y; Konishi, J; Yokoyama, A

    1992-02-01

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

  1. Integrating Dynamic Positron Emission Tomography and Conventional Pharmacokinetic Studies to Delineate Plasma and Tumor Pharmacokinetics of FAU, a Prodrug Bioactivated by Thymidylate Synthase.

    PubMed

    Li, Jing; Kim, Seongho; Shields, Anthony F; Douglas, Kirk A; McHugh, Christopher I; Lawhorn-Crews, Jawana M; Wu, Jianmei; Mangner, Thomas J; LoRusso, Patricia M

    2016-11-01

    FAU, a pyrimidine nucleotide analogue, is a prodrug bioactivated by intracellular thymidylate synthase to form FMAU, which is incorporated into DNA, causing cell death. This study presents a model-based approach to integrating dynamic positron emission tomography (PET) and conventional plasma pharmacokinetic studies to characterize the plasma and tissue pharmacokinetics of FAU and FMAU. Twelve cancer patients were enrolled into a phase 1 study, where conventional plasma pharmacokinetic evaluation of therapeutic FAU (50-1600 mg/m(2) ) and dynamic PET assessment of (18) F-FAU were performed. A parent-metabolite population pharmacokinetic model was developed to simultaneously fit PET-derived tissue data and conventional plasma pharmacokinetic data. The developed model enabled separation of PET-derived total tissue concentrations into the parent drug and metabolite components. The model provides quantitative, mechanistic insights into the bioactivation of FAU and retention of FMAU in normal and tumor tissues and has potential utility to predict tumor responsiveness to FAU treatment. © 2016, The American College of Clinical Pharmacology.

  2. 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.

  3. The role of single-photon emission computed tomography and SPECT/computed tomography in oncologic imaging.

    PubMed

    Brandon, David; Alazraki, Adina; Halkar, Raghuveer K; Alazraki, Naomi P

    2011-02-01

    Single-photon emission computed tomography (SPECT) and hybrid SPECT/computed tomography (SPECT/CT) cameras have emerged as a dominant technology providing invaluable tools in the diagnosis, staging, therapy planning, and treatment monitoring of multiple cancers over the past decade. In the same way that positron emission tomography (PET) benefited from the addition of CT, functional SPECT and anatomic CT data obtained as a single study have shown improvements in diagnostic imaging sensitivity and specificity by improving lesion conspicuity, reducing false positives, and clarifying indeterminate lesions. Furthermore, the anatomic imaging better localizes the functional data, which can be critical in surgical and therapy planning. As more disease-specific imaging agents become available, the role of SPECT/CT in the new paradigms of molecular imaging for personalized medicine will expand. Established and emerging uses of SPECT/CT in a wide variety of oncologic diseases, as well as radiation exposure issues, are reviewed. Published by Elsevier Inc.

  4. Positron emission tomography-computed tomography coregistration for diagnosis and intraoperative localization in recurrent nelson syndrome.

    PubMed

    Hintz, Eric B; Tomlin, Jeffery M; Chengazi, Vaseem; Vates, G Edward

    2013-06-01

    Recurrent pituitary disease presents unique challenges, including in some cases difficulty localizing a tumor radiographically. Here, we present the case of a patient with recurrent Nelson syndrome whose radiographic work-up was complicated by a significant parasellar metallic artifact. Positron emission tomography ultimately localized the lesion, and coregistration with computed tomography allowed for accurate intraoperative navigation. Additionally, we review a range of imaging techniques available in the evaluation of pituitary disease.

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

    PubMed

    Elumogo, Comfort O; Kochenderfer, James N; Civelek, A Cahid; Bluemke, David A

    2016-04-01

    Pigmented villonodular synovitis (PVNS) is a benign joint disease best characterized on magnetic resonance imaging (MRI). The role of fluorine 18 fluorodeoxyglucose ((18)F-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.

  6. 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

  7. 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).

  8. 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.

  9. Single photon emission computed tomography/computed tomography of the skull in malignant otitis externa.

    PubMed

    Chakraborty, Dhritiman; Bhattacharya, Anish; Kamaleshwaran, Koramadai Karuppusamy; Agrawal, Kanhaiyalal; Gupta, Ashok Kumar; Mittal, Bhagwant Rai

    2012-01-01

    Malignant otitis externa is a severe, rare infective condition of the external auditory canal and skull base. The diagnosis is generally made from a range of clinical, laboratory, and imaging findings. Technetium 99m methylene diphosphonate bone scintigraphy is known to detect osteomyelitis earlier than computed tomography. The authors present a patient with bilateral malignant otitis externa where the extent of skull base involvement was determined on 3-phase bone scintigraphy with single photon emission computed tomography/computed tomography. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Delta-9-tetrahydrocannabinol-induced dopamine release as a function of psychosis risk: 18F-fallypride positron emission tomography study.

    PubMed

    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 (18)F-fallypride to test the hypothesis that genetic risk for psychosis is expressed by differential induction of dopamine release by Δ(9)-THC (delta-9-tetrahydrocannabinol, the main psychoactive ingredient of cannabis). In a single dynamic PET scanning session, striatal dopamine release after pulmonary administration of Δ(9)-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 (18)F-fallypride displacement. Voxel-based statistical maps, representing specific D2/3 binding changes, were computed to localize areas with increased ligand displacement after Δ(9)-THC administration, reflecting dopamine release. While Δ(9)-THC was not associated with dopamine release in the control group, significant ligand displacement induced by Δ(9)-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 Δ(9)-THC in terms of increased endogenous dopamine release in individuals at risk for psychosis.

  11. Neural networks combined with region growing techniques for tumor detection in [18F]-fluorothymidine dynamic positron emission tomography breast cancer studies

    NASA Astrophysics Data System (ADS)

    Cseh, Zoltan; Kenny, Laura; Swingland, James; Bose, Subrata; Turheimer, Federico E.

    2013-03-01

    Early detection and precise localization of malignant tumors has been a primary challenge in medical imaging in recent years. Functional modalities play a continuously increasing role in these efforts. Image segmentation algorithms which enable automatic, accurate tumor visualization and quantification on noisy positron emission tomography (PET) images would significantly improve the quality of treatment planning processes and in turn, the success of treatments. In this work a novel multistep method has been applied in order to identify tumor regions in 4D dynamic [18F] fluorothymidine (FLT) PET studies of patients with locally advanced breast cancer. In order to eliminate the effect of inherently detectable high inhomogeneity inside tumors, specific voxel-kinetic classes were initially introduced by finding characteristic FLT-uptake curves with K-means algorithm on a set of voxels collected from each tumor. Image voxel sets were then split based on voxel time-activity curve (TAC) similarities, and models were generated separately on each voxel set. At first, artificial neural networks, in comparison with linear classification algorithms were applied to distinguish tumor and healthy regions relying on the characteristics of TACs of the individual voxels. The outputs of the best model with very high specificity were then used as input seeds for region shrinking and growing techniques, the application of which considerably enhanced the sensitivity and specificity (78.65% +/- 0.65% and 98.98% +/- 0.03%, respectively) of the final image segmentation model.

  12. 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

  13. Pilot study of positron emission tomography (PET) brain glucose metabolism to assess the efficacy of tongue and body acupuncture in cerebral palsy.

    PubMed

    Wong, Virginia C N; Sun, Jie-Guang; Yeung, David W C

    2006-06-01

    We aimed to assess the efficacy of tongue and body acupuncture with clinical function and brain glucose metabolism in children with a severe type of cerebral palsy. Four children were recruited. The motor function belonged to grade 5 of the Gross Motor Function Measure (i.e., completely nonambulatory). Daily tongue and body acupuncture was applied for 5 days a week for 8 weeks. The Functional Independence Scale for Children (WeeFIM), Clinical Global Impression Scale (CGIS), and positron emission tomography of the brain with [18F]fluorodeoxyglucose (FDG) were performed at baseline and after acupuncture. None of the children had any significant change in the Functional Independence Scale for Children score, despite the fact that all mothers scored 3 on the Clinical Global Impression Scale (i.e., 25% in improvement) in overall function. The brain glucose metabolism, however, showed a >10% increase in the frontal, parietal, temporal, and occipital cortices and cerebellum. Thus, a short course of tongue and body acupuncture was shown to increase brain glucose metabolism, despite lacking any clinical functional improvement seen during the eight-week course, possibly owing to the severity of the motor dysfunction and the short duration of treatment. The objective increase in brain glucose metabolism might serve as a surrogate marker for assessing the subclinical efficacy of an alternative treatment before any objective clinical improvement is evident. A larger-scale study for different degrees of severity of cerebral palsy and an impairment model should be undertaken to correlate clinical with neurometabolic change.

  14. 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.

  15. Neural Correlates of Exposure to Traumatic Pictures and Sound in Vietnam Combat Veterans with and without Posttraumatic Stress Disorder: A Positron Emission Tomography Study

    PubMed Central

    Bremner, J. Douglas; Staib, Lawrence H.; Kaloupek, Danny; Southwick, Steven M.; Soufer, Robert; Charney, Dennis S.

    2011-01-01

    Background Patients with posttraumatic stress disorder (PTSD) show a reliable increase in PTSD symptoms and physiological reactivity following exposure to traumatic pictures and sounds. In this study neural correlates of exposure to traumatic pictures and sounds were measured in PTSD. Methods Positron emission tomography and H2[15O] were used to measure cerebral blood flow during exposure to combat-related and neutral pictures and sounds in Vietnam combat veterans with and without PTSD. Results Exposure to traumatic material in PTSD (but not non-PTSD) subjects resulted in a decrease in blood flow in medial prefrontal cortex (area 25), an area postulated to play a role in emotion through inhibition of amygdala responsiveness. Non-PTSD subjects activated anterior cingulate (area 24) to a greater degree than PTSD patients. There were also differences in cerebral blood flow response in areas involved in memory and visuospatial processing (and by extension response to threat), including posterior cingulate (area 23), precentral (motor) and inferior parietal cortex, and lingual gyrus. There was a pattern of increases in PTSD and decreases in non-PTSD subjects in these areas. Conclusions The findings suggest that functional alterations in specific cortical and subcortical brain areas involved in memory, visuospatial processing, and emotion underlie the symptoms of patients with PTSD. PMID:10202567

  16. Blocking of fatty acid amide hydrolase activity with PF-04457845 in human brain: a positron emission tomography study with the novel radioligand [(11)C]CURB.

    PubMed

    Boileau, Isabelle; Rusjan, Pablo M; Williams, Belinda; Mansouri, Esmaeil; Mizrahi, Romina; De Luca, Vincenzo; Johnson, Douglas S; Wilson, Alan A; Houle, Sylvain; Kish, Stephen J; Tong, Junchao

    2015-11-01

    Positron emission tomography with [(11)C]CURB was recently developed to quantify fatty acid amide hydrolase (FAAH), the enzyme responsible for hydrolyzing the endocannabinoid anandamide. This study investigated the test-retest reliability of [(11)C]CURB as well as its in vivo specificity and the validity of the kinetic model by using the highly specific FAAH inhibitor, PF-04457845. Five healthy volunteers completed test-retest [(11)C]CURB scans 1 to 2 months apart and six subjects completed baseline and blocking scans on the same day after PF-04457845 (p.o.) administration (1, 4, or 20 mg; n=2 each). The composite parameter λk3 (an index of FAAH activity, λ=K1/k2) was estimated using an irreversible two-tissue compartment model with plasma input function. There were no clinically observable responses to oral PF-04457845 or [(11)C]CURB injection. Oral administration of PF-04457845 reduced [(11)C]CURB binding to a homogeneous level at all three doses, with λk3 values decreased by ⩾91%. Excellent reproducibility and good reliability (test-retest variability=9%; intraclass correlation coefficient=0.79) were observed across all regions of interest investigated. Our findings suggest that λk3/[(11)C]CURB is a reliable, highly sensitive, and selective tool to measure FAAH activity in human brain in vivo. Moreover, PF-04457845 is a highly potent FAAH inhibitor (>95% inhibition at 1 mg) in living human brain.

  17. Comparison of Cannabinoid CB1 Receptor Binding in Adolescent and Adult Rats: A Positron Emission Tomography Study Using [18F]MK-9470

    PubMed Central

    Verdurand, Mathieu; Nguyen, Vu; Stark, Daniela; Zahra, David; Gregoire, Marie-Claude; Greguric, Ivan; Zavitsanou, Katerina

    2011-01-01

    Despite the important role of cannabinoid CB1 receptors (CB1R) in brain development, little is known about their status during adolescence, a critical period for both the development of psychosis and for initiation to substance abuse. In the present study, we assessed the ontogeny of CB1R in adolescent and adult rats in vivo using positron emission tomography with [18F]MK-9470. Analysis of covariance (ANCOVA) to control for body weight that would potentially influence [18F]MK-9470 values between the two groups revealed a main effect of age (F(1,109)=5.0, P = 0.02) on [18F]MK-9470 absolute binding (calculated as percentage of injected dose) with adult estimated marginal means being higher compared to adolescents amongst 11 brain regions. This finding was confirmed using in vitro autoradiography with [3H]CP55,940 (F(10,99)=140.1, P < 0.0001). This ontogenetic pattern, suggesting increase of CB1R during the transition from adolescence to adulthood, is the opposite of most other neuroreceptor systems undergoing pruning during this period. PMID:22187642

  18. Extracardiac abnormalities on rubidium-82 cardiac positron emission tomography/computed tomography.

    PubMed

    Mirpour, Sahar; Khandani, Amir H

    2011-04-01

    The role of rubidium-82 (Rb) in recognizing extracardiac diseases is minimally investigated. The aim of this study was to evaluate the frequency and incremental added value of extracardiac findings on Rb cardiac positron emission tomography/computed tomography (PET/CT) studies. The study included all consecutive patients who were referred from July 2008 to June 2010 for Rb cardiac PET/CT to our institution. A blinded reader reviewed the images retrospectively to assess abnormal extracardiac PET findings. Images of 406 patients (142 men; 264 women) with a mean age±standard deviation of 59.72±12.93 years (range: 18-91 years) were reviewed. Incidental extracardiac abnormalities were found in 67 of 406 patients (16.5%). Among them, eight patients had malignant etiologies (1.9%). Incidental extracardiac findings were present in a significant portion of patients undergoing Rb cardiac PET/CT studies. Although most of the extracardiac findings on Rb cardiac PET/CT studies represented clinically known pathologies, these incidental findings on routine Rb cardiac PET/CT scans may have a significant clinical impact on a small number of patients, and offer the referring physician the chance to obtain additional clinically relevant information.

  19. Role of positron emission tomography/computed tomography in breast cancer.

    PubMed

    Bourgeois, Austin C; Warren, Lance A; Chang, Ted T; Embry, Scott; Hudson, Kathleen; Bradley, Yong C

    2013-09-01

    Although positron emission tomography (PET) imaging may not be used in the diagnosis of breast cancer, the use of PET/computed tomography is imperative in all aspects of breast cancer staging, treatment, and follow-up. PET will continue to be relevant in personalized medicine because accurate tumor status will be even more critical during and after the transition from a generic metabolic agent to receptor imaging. Positron emission mammography is an imaging proposition that may have benefits in lower doses, but its use is limited without new radiopharmaceuticals. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. 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.

  1. 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.

  2. The investigation of Alzheimer's disease with single photon emission tomography.

    PubMed Central

    Burns, A; Philpot, M P; Costa, D C; Ell, P J; Levy, R

    1989-01-01

    Twenty patients satisfying standard clinical criteria for Alzheimer's disease (AD) and six age-matched normal controls were studied using 99mTc hexamethyl-propyleneamine oxime and single photon emission tomography. The AD patients had lower regional cerebral blood flow (rCBF) in the temporal and posterior parietal lobes compared to controls. AD patients with apraxia and aphasia had lower rCBF in the lateral temporal and posterior parietal lobes than AD patients without these features. Within the AD group, correlations were found between neuropsychological tests and rCBF: praxis correlated with posterior parietal activity, memory with left temporal lobe activity and language with activity throughout the left hemisphere. Images PMID:2467967

  3. Chelators for copper radionuclides in positron emission tomography radiopharmaceuticals.

    PubMed

    Cai, Zhengxin; Anderson, Carolyn J

    2014-04-01

    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. © 2013 The Authors. J. Label Compd. Radiopharm published by John Wiley & Sons Ltd.

  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. MR imaging and positron emission tomography of cortical heterotopia

    SciTech Connect

    Bairamian, D.; Di Chiro, G.; Theodore, W.H.; Holmes, M.D.; Dorwart, R.H.; Larson, S.M.

    1985-11-01

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

  6. 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…

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

    SciTech Connect

    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. 117 refs., 4 figs., 4 tabs.

  8. 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…

  9. Principles and clinical applications of positron emission tomography.

    PubMed

    Gardner, S F; Green, J A; Bednarczyk, E M; Farnett, L; Miraldi, F

    1992-06-01

    The basics of positron emission tomography (PET) are presented, including the physics, instrumentation, and radiopharmaceuticals involved; the clinical and research applications; and the cost. In PET, organic molecules labeled with positron-emitting radionuclides are injected or inhaled, and the high-energy photons produced by annihilation events are detected by paired, integrated crystal detectors. A computer uses the lines of origin of these photons to reconstruct a three-dimensional map of a functioning organ system. The positron-emitting radionuclides most often used are carbon 11, oxygen 15, nitrogen 13, fluorine 18, and rubidium 82. PET imaging centers usually consist of a cyclotron facility, a radiochemistry facility, a PET scanner, and computers for image reconstruction. Radiopharmaceuticals used in PET may be divided into blood flow-imaging agents, metabolic imaging agents, and drug receptor-imaging agents. Although PET is still primarily a research tool, it has shown diagnostic potential in neurology, cardiology, and oncology. It has also shown promise as a tool for pharmacologic assessment, as in studies of the effects of the fluorinated quinolones on cerebral blood flow and glucose metabolism. PET may become important in drug development because it yields specific information relatively noninvasively. A single study carries an average break-even price tag of $1500-$2000; rigorous cost-benefit analyses should be conducted before society is asked to subsidize such costs. Positron emission tomography is a frontier technology for which valuable clinical applications are being discovered. Pharmacists can contribute enormously to PET applications and at the same time establish a unique subspecialty for the profession.

  10. Role of positron emission tomography in urological oncology.

    PubMed

    Rioja, Jorge; Rodríguez-Fraile, Macarena; Lima-Favaretto, Ricardo; Rincón-Mayans, Anibal; Peñuelas-Sánchez, Iván; Zudaire-Bergera, Juan Javier; Parra, Raul O

    2010-12-01

    • Positron emission tomography (PET) is a diagnostic tool using radiotracers to show changes in metabolic activities in tissues. We analysed the role of PET and PET/computed tomography (CT) in the diagnosis, staging, and follow-up of urological tumours. • A critical, non-structured review of the literature of the role of PET and PET/CT in urological oncology was conducted. • PET and PET/CT can play a role in the management of urological malignancies. For prostate cancer, the advances in radiotracers seems promising, with novel radiotracers yielding better diagnostic and staging results than 18F-fluorodeoxyglucose (18F-FDG). In kidney cancer, PET and PET/CT allow a proper diagnosis before the pathological examination of the surgical specimen. For testis cancer, PET and PET/CT have been shown to be useful in the management of seminoma tumours. In bladder cancer, these scans allow a better initial diagnosis for invasive cancer, while detecting occult metastases. • PET and its combined modality PET/CT have shown their potential in the diagnosis of urological malignancies. However, further studies are needed to establish the role of PET in the management of these diseases. Future applications of PET may involve fusion techniques such as magnetic resonance imaging with PET.

  11. Orbital positron emission tomography/computed tomography (PET/CT) imaging findings in graves ophthalmopathy

    PubMed Central

    2013-01-01

    Background We aimed to describe orbital positron emission tomography/computed tomography (PET/CT) imaging findings, both structural and metabolic, in different clinical stages of Graves ophthalmopathy (GO). This prospective, observational, cross-sectional study examined 32 eyes of 16 patients with GO. Methods Patients were assessed with a complete ophthalmological evaluation and assigned a VISA classification for GO. All patients underwent serum thyroid hormone measurement, antibody profile, and 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT) of the orbits. The 18-FDG uptake on PET images was expressed in terms of maximum standard uptake value (SUVmax). CT images were analyzed, and orbital structures were measured in millimeters. Vision, inflammation, strabismus, and overall appearance were assessed according to the VISA classification system, thyroid hormone levels, antibody values, 18-FDG uptake, and thickness of orbital structures. Results Altogether, 32 eyes of 16 patients (10 women, 6 men; mean age 44.31 ± 13 years, range 20–71 years) were included. Three patients were hypothyroid, seven were euthyroid, and six were hyperthyroid. CT measurements of extraocular muscle diameter were elevated (P < 0.05), and muscle 18-FDG uptake values were increased. Eyes with a clinical VISA inflammation score of ≤ 4 had an average extraocular muscle SUVmax of 3.09, and those with a score of ≥ 5 had an average SUVmax of 3.92 (P = 0.09), showing no clear correlation between clinically observed inflammation and 18-FDG uptake. 18-FDG uptake values also did not show a correlation with extraocular muscle diameter as measured by CT (R2 = 0.0755, P > 0.05). Conclusions We demonstrated a lack of correlation between 18-FDG extraocular muscle uptake and either clinical inflammation score or muscle diameter. Although 18-FDG uptake has been used as an inflammation marker in other pathologies, inflammation in GO may

  12. 77 FR 71802 - Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-04

    ... ``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). DATES... guidance entitled ``Investigational New Drug Applications for Positron Emission Tomography (PET) Drugs...

  13. Normal values of cardiac mechanical synchrony parameters using gated myocardial perfusion single-photon emission computed tomography: Impact of population and study protocol

    PubMed Central

    Mukherjee, Anirban; Singh, Harmandeep; Patel, Chetan; Sharma, Gautam; Roy, Ambuj; Naik, Nitish

    2016-01-01

    Purpose of the Study: Normal values of cardiac mechanical synchrony parameters in gated myocardial perfusion single-photon emission computed tomography (GMPS) are well established in literature from the Western population. The aim of the study is to establish normal values of mechanical synchrony with GMPS in Indian population and to find out whether it differs significantly from established values. Procedure: We retrospectively analyzed 1 day low-dose stress/high-dose rest GMPS studies of 120 patients (sixty males, 52 ± 11.7 years) with low pretest likelihood of coronary artery disease and having normal GMPS study. In GMPS, first-harmonic fast Fourier transform was used to extract a phase array using commercially available software. Phase standard deviation (PSD) and phase histogram bandwidth (PHB) were used to quantify cardiac mechanical dyssynchrony. Results: The values obtained were as follows, PSD: In men, 14.3 ± 4.7 (stress) and 8.9 ± 2.9 (rest), in women 11 ± 4 (stress) and 7.7 ± 2.7 (rest), and PHB: In men, 40.1 ± 11.9 (stress) and 30.6 ± 7.6 (rest), in women, 34.7 ± 12.6 (stress) and 25.3 ± 8.6 (rest). The value of PSD and PHB was significantly less in Indian population as compared with established values in literature. We also observed that synchrony indices derived from the low-dose stress studies are higher than high-dose rest studies. Conclusions: The value of synchrony parameters differs significantly according to population and methodology suggesting that specific population and methodology-based normal database for assessment of cardiac mechanical dyssynchrony should be established. PMID:27833309

  14. 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.

  15. 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.

  16. 5-HT(1A) receptor binding changes in patients with major depressive disorder before and after antidepressant treatment: a pilot [¹⁸F]MPPF positron emission tomography study.

    PubMed

    Lothe, Amélie; Saoud, Mohamed; Bouvard, Sandrine; Redouté, Jérôme; Lerond, Jérôme; Ryvlin, Philippe

    2012-07-30

    This is the first [¹⁸F]MPPF PET study in positron emission tomography study in depressed patients, both before and after treatment with a selective serotonin reuptake inhibitor (SSRI). Dynamic changes in [¹⁸F]MPPF binding potential were observed primarily in the medial orbital regions from baseline to 30 days of treatment, suggesting SSRI-mediated serotoninergic adaptative mechanisms. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. 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.

  18. Magnetosensory function in rats: localization using positron emission tomography.

    PubMed

    Frilot, Clifton; Carrubba, Simona; Marino, Andrew A

    2009-05-01

    The aim of this study was to show that low-strength electromagnetic fields (EMFs) produced evoked potentials in rats and to localize the activated region in the brain. In response to a 2.5-G, 60-Hz stimulus, onset- and offset-evoked potentials were detected (P < 0.05 in each of the 10 animals studied); the evoked potentials had the same magnitude, latency, and nonlinear relationship to the field seen in previous studies on rabbits and human subjects. The neuroanatomical region of activation associated with the electrophysiological effect was identified by positron emission tomography using fluorodeoxyglucose. Paired emission scans (the same animal with and without field treatment) from 10 additional rats were differenced and averaged to produce a t-statistic image using the pooled variance; the t value of each voxel was compared with a calculated critical t value to identify the activated voxels (P < 0.05). A brain volume of 13 mm(3) (15 voxels) located in the posterior, central cerebellum was found to have been activated by exposure to the field. Taken together, the results indicated that magnetosensory evoked potentials in the rats were associated with increased glucose utilization in the cerebellum, thereby supporting earlier evidence that EMF transduction occurred in the brain.

  19. Arterial Spin Labeling Perfusion Magnetic Resonance Image with Dual Postlabeling Delay: A Correlative Study with Acetazolamide Loading (123)I-Iodoamphetamine Single-Photon Emission Computed Tomography.

    PubMed

    Haga, Sei; Morioka, Takato; Shimogawa, Takafumi; Akiyama, Tomoaki; Murao, Kei; Kanazawa, Yuka; Sayama, Tetsuro; Arakawa, Shuji

    2016-01-01

    Perfusion magnetic resonance image with arterial spin labeling (ASL) provides a completely noninvasive measurement of cerebral blood flow (CBF). However, arterial transient times can have a marked effect on the ASL signal. For example, a single postlabeling delay (PLD) of 1.5 seconds underestimates the slowly streaming collateral pathways that maintain the cerebrovascular reserve (CVR). To overcome this limitation, we developed a dual PLD method. A dual PLD method of 1.5  and 2.5 seconds was compared with (123)I-iodoamphetamine single-photon emission computed tomography with acetazolamide loading to assess CVR in 10 patients with steno-occlusive cerebrovascular disease. In 5 cases (Group A), dual PLD-ASL demonstrated low CBF with 1.5-second PLD in the target area, whereas CBF was improved with 2.5-second PLD. In the other 5 cases (Group B), dual PLD-ASL depicted low CBF with 1.5-second PLD, and no improvement in CBF with 2.5-second PLD in the target area was observed. On single-photon emission computed tomography, CVR was maintained in Group A but decreased in Group B. Although dual PLD methods may not be a completely alternative test for (123)I-iodoamphetamine single-photon emission computed tomography with acetazolamide loading, it is a feasible, simple, noninvasive, and repeatable technique for assessing CVR, even when employed in a routine clinical setting. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  20. Iodine-131 meta-iodobezylguanidine single photon emission computed tomography/computerized tomography in diagnosis of neuro-endocrine tumors

    PubMed Central

    Harisankar, Chidambaram Natrajan Balasubramanian; Mittal, Bhagwant Rai; Bhattacharya, Anish; Kashyap, Raghava; Bhansali, Anil

    2012-01-01

    Metaiodobenzyl guanidine (MIBG) is a derivative of guanethidine and acts as an analogue of nor-epinephrine and is widely used in the imaging of tumors of neuro-endocrine origin. Iodine-123 MIBG has ideal imaging characteristics but is expensive with limited availability. Iodine-131 MIBG is widely used in India and is cheap. Hybrid single photon emission computed tomography (SPECT)/computerized tomography (CT) allows for anatomico-functional imaging and is being tried in MIBG studies. However, the experience with I-131 MIBG is limited. We present a pictorial assay of I-131 MIBG SPECT/CT findings in various MIBG avid tumors. PMID:23599604

  1. Multimodal sentinel lymph node mapping with single-photon emission computed tomography (SPECT)/computed tomography (CT) and photoacoustic tomography.

    PubMed

    Akers, Walter J; Edwards, W Barry; Kim, Chulhong; Xu, Baogang; Erpelding, Todd N; Wang, Lihong V; Achilefu, Samuel

    2012-03-01

    The identification of cancer cells in the lymph nodes surrounding a tumor is important in establishing a prognosis. Optical detection techniques such as fluorescence and photoacoustic tomography (PAT) have been reported in preclinical studies for noninvasive sentinel lymph node (SLN) mapping. A method for validation of these techniques is needed for clinical trials. We report the use of a multimodal optical-radionuclear contrast agent as a validation tool for PAT in a preclinical model. Methylene blue (MB) was radiolabeled with (125)I for multimodal SLN mapping and used in conjunction with MB to assess the feasibility of multimodal SLN mapping in a rat model by PAT and single-photon emission computed tomography (SPECT). MB provided sufficient contrast for identifying SLNs noninvasively with a PAT system adapted from a clinical ultrasound imaging system. The signal location was corroborated by SPECT using (125)I labeled MB. The translation of PAT into the clinic can be facilitated by a direct comparison with established imaging methods using a clinically relevant dual SPECT and photoacoustic imaging agent. The new high-resolution PAT is a promising technology for the sensitive and accurate SLN detection in cancer patients. Copyright © 2012 Mosby, Inc. All rights reserved.

  2. Neuroimaging of translocator protein in patients with systemic lupus erythematosus: a pilot study using [11C]DPA-713 positron emission tomography.

    PubMed

    Wang, Yuchuan; Coughlin, Jennifer M; Ma, Shuangchao; Endres, Christopher J; Kassiou, Michael; Sawa, Akira; Dannals, Robert F; Petri, Michelle; Pomper, Martin G

    2016-07-06

    Inflammation secondary to autoantibody-mediated effects occurring in multiple organs is a hallmark of systemic lupus erythematosus (SLE). The inflammatory response to SLE-mediated damage in brain parenchyma has been postulated in both normal and cognitively impaired individuals. Our goal is to use molecular imaging to investigate the distribution within the brain of the mitochondrial translocator protein (TSPO) that is upregulated during glial cell activation, and is considered as a marker of brain injury and repair. We sought to characterize TSPO distribution in the brain of SLE patients using positron emission tomography (PET) and [(11)C]DPA-713 (DPA), a radiopharmaceutical that targets TSPO. We imaged 11 healthy controls and 10 patients with SLE (years of diagnosis: 13.0 ± 7.7), all between the ages of 22 and 52. Among the nine brain regions studied, no statistically significant increases in DPA binding were observed in SLE. Instead, there was a significant decrease in TSPO distribution in the cerebellum and hippocampus of SLE patients, as compared to healthy controls. Such decreases were most significant in cognitively normal SLE subjects, but showed pseudo-normalization in those with cognitive impairment, due to higher cerebellar and hippocampal DPA binding in the cognitively impaired (versus normal) SLE brain. Results from this pilot study suggest a link between diminished regional TSPO expression in the brain of patients with SLE, as well as possible glial cell activation within the cerebellum and hippocampus of cognitively impaired individuals with SLE. Further studies are needed to elucidate how mitochondrial dysfunction and glial cell activation may act together in SLE and SLE-mediated neurocognitive deficits. © The Author(s) 2016.

  3. Histamine H₁ receptor occupancy by the new-generation antidepressants fluvoxamine and mirtazapine: a positron emission tomography study in healthy volunteers.

    PubMed

    Sato, Hirotoshi; Ito, Chihiro; Tashiro, Manabu; Hiraoka, Kotaro; Shibuya, Katsuhiko; Funaki, Yoshihito; Iwata, Ren; Matsuoka, Hiroo; Yanai, Kazuhiko

    2013-11-01

    Histamine H₁ antagonists have hypnotic, appetite-promoting, and sedative effects. The affinities of various antidepressants for histamine receptors have only been partially determined in vitro and animal study. Positron emission tomography (PET) can clarify the in vivo dynamics of antidepressants at histamine receptors. We performed human PET imaging with [¹¹C]doxepin, a selective PET ligand of the histamine H₁ receptor (H₁R), to study the in vivo affinities of fluvoxamine and mirtazapine for the H₁R. The subjects were five male healthy Japanese volunteers. We performed cross-randomized PET imaging after single oral administration of fluvoxamine (25mg), mirtazapine (15 mg), or placebo. PET data were analyzed by region-of-interest and voxel-by-voxel analysis. We concurrently measured plasma drug concentrations, using liquid chromatography/tandem mass spectrometry and subjective sleepiness. The binding potential ratio of mirtazapine in brain cortex was significantly lower than that of fluvoxamine or placebo. Fluvoxamine did not occupy the H₁R, whereas H₁R occupancy (H₁RO) of mirtazapine reached 80-90 % in the cerebral neocortex. In the voxel-by-voxel analysis, the binding potential of mirtazapine was significantly lower than placebo in the dorsolateral prefrontal cortex, lateral temporal cortex, anterior cingulate gyrus, and posterior cingulate gyrus. The H₁RO of mirtazapine depended on the plasma drug concentration (AUC(0-180 min)) and was related to subjective sleepiness. Our results demonstrate a low affinity of fluvoxamine and a very high affinity of mirtazapine for the human brain H₁R in vivo. This study provides a basis for investigating the efficacy of new-generation antidepressants in central histamine systems.

  4. Occupancy of α7 Nicotinic Acetylcholine Receptors in the Brain by Tropisetron: A Positron Emission Tomography Study Using [11C]CHIBA-1001 in Healthy Human Subjects

    PubMed Central

    Ishikawa, Masatomo; Sakata, Muneyuki; Toyohara, Jun; Oda, Keiichi; Ishii, Kenji; Wu, Jin; Yoshida, Taisuke; Iyo, Masaomi; Ishiwata, Kiichi

    2011-01-01

    Objective Agonists of α7-nicotinic acetylcholine receptors (nAChRs) have been developed as potential therapeutic drugs for neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. Positron emission tomography (PET) is a noninvasive brain imaging technique to measure receptor occupancy in the living human brain. Although much effort has been expended to create specific PET radioligands for α7-nAChRs in the brain, only 4-[11C]methylphenyl-1,4-diazabicyclo[3.2.2.]nonane-4-carboxylate ([11C]CHIBA-1001) is currently available for clinical studies. In contrast, two 5-hydroxytryptamine-3 (5-HT3) receptor antagonists, tropisetron and ondansetron, have been used to treat patients with chemotherapy-induced or postoperative nausea and vomiting. Furthermore, tropisetron, but not ondansetron, possesses high affinity for α7-nAChRs. In the present study, we evaluated the receptor occupancy in the human brain after a single oral administration of tropisetron and ondansetron using [11C]CHIBA-1001 and PET. Methods Two serial dynamic PET scans using [11C]CHIBA-1001 in healthy non-smoking male subjects were performed before and after receiving an oral administration of these medications. Results A single oral administration of tropisetron, but not ondansetron, decreased the total distribution volume of [11C]CHIBA-1001 in the human brain. Conclusion This study shows that tropisetron, but not ondansetron, could bind to α7-nAChRs in the human brain after a single oral administration. Therefore, [11C]CHIBA-1001 may be a useful PET radioligand to measure the occupancy of α7-nAChRs in the human brain. PMID:23430308

  5. 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

  6. Noninvasive multimodality imaging of the tumor microenvironment: registered dynamic magnetic resonance imaging and positron emission tomography studies of a preclinical tumor model of tumor hypoxia.

    PubMed

    Cho, HyungJoon; Ackerstaff, Ellen; Carlin, Sean; Lupu, Mihaela E; Wang, Ya; Rizwan, Asif; O'Donoghue, Joseph; Ling, C Clifton; Humm, John L; Zanzonico, Pat B; Koutcher, Jason A

    2009-03-01

    In vivo knowledge of the spatial distribution of viable, necrotic, and hypoxic areas can provide prognostic information about the risk of developing metastases and regional radiation sensitivity and may be used potentially for localized dose escalation in radiation treatment. In this study, multimodality in vivo magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging using stereotactic fiduciary markers in the Dunning R3327-AT prostate tumor were performed, focusing on the relationship between dynamic contrast-enhanced (DCE) MRI using Magnevist (Gd-DTPA) and dynamic (18)F-fluoromisonidazole ((18)F-Fmiso) PET. The noninvasive measurements were verified using tumor tissue sections stained for hematoxylin/eosin and pimonidazole. To further validate the relationship between (18)F-Fmiso and pimonidazole uptake, (18)F digital autoradiography was performed on a selected tumor and compared with the corresponding pimonidazole-stained slices. The comparison of Akep values (kep = rate constant of movement of Gd-DTPA between the interstitial space and plasma and A = amplitude in the two-compartment model (Hoffmann U, Brix G, Knopp MV, Hess T and Lorenz WJ (1995). Magn Reson Med 33, 506-514) derived from DCE-MRI studies and from early (18)F-Fmiso uptake PET studies showed that tumor vasculature is a major determinant of early (18)F-Fmiso uptake. A negative correlation between the spatial map of Akep and the slope map of late (last 1 hour of the dynamic PET scan) (18)F-Fmiso uptake was observed. The relationships between DCE-MRI and hematoxylin/eosin slices and between (18)F-Fmiso PET and pimonidazole slices confirm the validity of MRI/PET measurements to image the tumor microenvironment and to identify regions of tumor necrosis, hypoxia, and well-perfused tissue.

  7. Noninvasive Multimodality Imaging of the Tumor Microenvironment: Registered Dynamic Magnetic Resonance Imaging and Positron Emission Tomography Studies of a Preclinical Tumor Model of Tumor Hypoxia12

    PubMed Central

    Cho, HyungJoon; Ackerstaff, Ellen; Carlin, Sean; Lupu, Mihaela E; Wang, Ya; Rizwan, Asif; O'Donoghue, Joseph; Ling, C Clifton; Humm, John L; Zanzonico, Pat B; Koutcher, Jason A

    2009-01-01

    In vivo knowledge of the spatial distribution of viable, necrotic, and hypoxic areas can provide prognostic information about the risk of developing metastases and regional radiation sensitivity and may be used potentially for localized dose escalation in radiation treatment. In this study, multimodality in vivo magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging using stereotactic fiduciary markers in the Dunning R3327-AT prostate tumor were performed, focusing on the relationship between dynamic contrast-enhanced (DCE) MRI using Magnevist (Gd-DTPA) and dynamic 18F-fluoromisonidazole (18F-Fmiso) PET. The noninvasive measurements were verified using tumor tissue sections stained for hematoxylin/eosin and pimonidazole. To further validate the relationship between 18F-Fmiso and pimonidazole uptake, 18F digital autoradiography was performed on a selected tumor and compared with the corresponding pimonidazole-stained slices. The comparison of Akep values (kep = rate constant of movement of Gd-DTPA between the interstitial space and plasma and A = amplitude in the two-compartment model (Hoffmann U, Brix G, Knopp MV, Hess T and Lorenz WJ (1995). Magn Reson Med 33, 506–514) derived from DCE-MRI studies and from early 18F-Fmiso uptake PET studies showed that tumor vasculature is a major determinant of early 18F-Fmiso uptake. A negative correlation between the spatial map of Akep and the slope map of late (last 1 hour of the dynamic PET scan) 18F-Fmiso uptake was observed. The relationships between DCE-MRI and hematoxylin/eosin slices and between 18F-Fmiso PET and pimonidazole slices confirm the validity of MRI/PET measurements to image the tumor microenvironment and to identify regions of tumor necrosis, hypoxia, and well-perfused tissue. PMID:19242606

  8. Striatal Dopamine Transporter Modulation After Rotigotine: Results From a Pilot Single-Photon Emission Computed Tomography Study in a Group of Early Stage Parkinson Disease Patients.

    PubMed

    Rossi, Carlo; Genovesi, Dario; Marzullo, Paolo; Giorgetti, Assuero; Filidei, Elena; Corsini, Giovanni Umberto; Bonuccelli, Ubaldo; Ceravolo, Roberto

    Several in vitro data have reported negative interference by dopamine-agonists on the expression of dopamine transporter (DAT), whereas the majority of imaging studies have shown that neither L-dopa nor dopamine-agonists interfere with DAT availability. As yet, there are no in vivo studies on DAT expression after treatment with rotigotine. We evaluated presynaptic nigrostriatal function in 8 patients with de novo Parkinson disease (age, 59 ± 6.2 years; male/female sex, 5/3) using 123-I- N-ω-fluoropropyl-2-β-carbomethoxy-3-β-(4-iodophenyl)nortropane (FP-CIT) single-photon emission computed tomography before and after 3 months of treatment with rotigotine (mean dose, 7.75 ± 1.98 mg). For data analysis, specific (left and right caudate, left and right putamen) to nonspecific (occipital cortex) binding ratios, putamen-to-caudate ratios, and asymmetry indices were calculated. After rotigotine, motor symptoms improved in all patients (Unified Parkinson Disease Rating Scale III mean score, 11.88 ± 2.59 vs 7.63 ± 1.92 on therapy; P = 0.0022). Striatal FP-CIT levels showed a significant improvement in every patient at the follow-up scan. Comparisons between before and after treatment in the whole group revealed a significant improvement in FP-CIT uptake in both caudate and putamen (P < 0.001 in each nucleus). Putamen-to-caudate ratio and asymmetry indices did not show any significant difference before and after treatment. Although the study population was small, we found DAT overexpression after chronic treatment with rotigotine, presumably related to its pharmacological profile. The DAT upregulation by rotigotine in an opposite direction with respect to early Parkinson disease compensatory mechanisms might reduce the risk of dyskinesia, but it could imply less motor benefit because of less stimulation by the dopamine itself on dopaminergic receptors.

  9. 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

  10. 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.

  11. [Positron-emission tomography/computed tomography: artifacts and pitfalls in cancer patients].

    PubMed

    Gorospe Sarasúa, L; Echeveste Aizpurúa, J; Raman, S

    2006-01-01

    Diagnostic accuracy and correct initial staging (or restaging) are fundamental in the management of oncological patients and can directly influence therapeutic decisions. The combination of positron-emission tomography (PET) and computed tomography (CT) in a single scanner (PET/TC) represents an important achievement in the fields of oncology, nuclear medicine, and radiology. These scanners allow morphologic images (obtained by CT) to be fused and correlated with metabolic images (obtained by PET) to a high degree of accuracy. In addition to an understanding of the physiopathology of cancer and the behavior of the different types of neoplasms, the correct interpretation of PET/CT images requires in-depth knowledge of the physiological distribution of the F-18 fluorodeoxyglucose molecule (FDG, currently the most widely used marker in oncology), of the frequent physiological variations in its distribution, and of the possible causes of non-malignant pathological FDG uptake. Furthermore, the use of CT data to correct attenuation and reconstruct PET images in PET/CT scanners can generate some characteristic artifacts specific to this new diagnostic tool, and these can lead to misinterpretation with potential therapeutic implications. This article reviews and illustrates some of the most common artifacts and pitfalls that can appear in PET/CT studies. The detection and correct interpretation of these findings are essential for the appropriate management of oncologic patients.

  12. Small Animal Imaging using a Clinical Positron Emission Tomography/Computed Tomography and Super-Resolution

    PubMed Central

    DiFilippo, Frank P.; Patel, Sagar; Asosingh, Kewal; Erzurum, Serpil

    2013-01-01

    Considering the high cost of dedicated small animal positron emission tomography/computed tomography (PET/CT), an acceptable alternative in many situations might be clinical PET/CT. However spatial resolution and image quality are of concern. The utility of clinical PET/CT for small-animal research and image quality improvements from super-resolution (spatial subsampling) were investigated. National Electrical Manufacturers Association (NEMA) NU 4 phantom and mouse data were acquired with a clinical PET/CT scanner, both as conventional static and stepped scans. Static scans were reconstructed with and without point spread function (PSF) modeling. Stepped images were postprocessed with iterative deconvolution to produce super-resolution images. Image quality was markedly improved using the super-resolution technique, avoiding certain artifacts produced by PSF modeling. The 2-mm rod of the NU 4 phantom was visualized with high contrast, and the major structures of the mouse were well resolved. Although not a perfect substitute for a state-of-the-art small animal PET/CT scanner, a clinical PET/CT scanner with super-resolution produces acceptable small-animal image quality for many preclinical research studies. PMID:22554485

  13. 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.

  14. 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

  15. No evidence for a role of the serotonin 4 receptor in five-factor personality traits: A positron emission tomography brain study.

    PubMed

    Stenbæk, Dea Siggaard; Dam, Vibeke Høyrup; Fisher, Patrick MacDonald; Hansen, Nanna; Hjordt, Liv Vadskjær; Frokjaer, Vibe Gedsoe

    2017-01-01

    Serotonin (5-HT) brain architecture appears to be implicated in normal personality traits as supported by genetic associations and studies using molecular brain imaging. However, so far, no studies have addressed potential contributions to variation in normal personality traits from in vivo serotonin 4 receptor (5-HT4R) brain availability, which has recently become possible to image with Positron Emission Tomography (PET). This is particularly relevant since availability of 5-HT4R has been shown to adapt to synaptic levels of 5-HT and thus offers information about serotonergic tone in the healthy brain. In 69 healthy participants (18 females), the associations between personality traits assessed with the five-factor NEO Personality Inventory-Revised (NEO PI-R) and regional cerebral 5-HT4R binding in neocortex, amygdala, hippocampus, and anterior cingulate cortex (ACC) were investigated using linear regression models. The associations between each of the five personality traits and a latent variable construct of global 5-HT4R levels were also evaluated using latent variable structural equation models. We found no significant associations between the five NEO personality traits and regional 5-HT4R binding (all p-values > .17) or the latent construct of global 5-HT4R levels (all p-values > .37). Our findings indicate that NEO personality traits and 5-HT4R are not related in healthy participants. Under the assumption that global 5-HT4R levels index 5-HT tone, our data also suggest that 5-HT tone per se is not directly implicated in normal personality traits.

  16. Motion-frozen Imaging by Gated Myocardial Perfusion Single Photon Emission Computed Tomography Using Multi-focus Fan Beam Collimator in Thallium-201 Study.

    PubMed

    Takahashi, Kaito; Takeuchi, Takashi; Hosokai, Yoshiyuki; Odagiri, Hayato; Saito, Haruo

    This study aimed to evaluate the statistical noise of motion-frozen (MF) image generated by gated myocardial perfusion single photon emission computed tomography (SPECT) imaging using IQ · SPECT and to determine the optimal acquisition and reconstruction parameters for MF image using IQ · SPECT. A movement cardiac phantom and static cardiac phantom were used to acquire the MF images. The acquisition times used were different in 8 and 16 frames per R-R interval, and varying reconstruction parameters (subset and iteration) were used. We determined the %CV value, contrast, and normalized mean square error (NMSE) to evaluate the image quality. The %CV value for a MF image with IQ · SPECT was lower than that for a conventional non-gated myocardial perfusion SPECT (MPS) image with low energy high resolution (LEHR). With regard to the acquisition parameters, the contrast did not change when the acquisition time was increased in 8 and 16 frames per R-R interval. NMSE converged in 56 beats/view in 8 frames per R-R interval. With regard to the reconstruction parameters, the contrast and the %CV value of the anterior and septal wall converged in update 40. The minimum NMSE in subsets 1, 2, and 3 were almost similar. Uniformity in the MF image with IQ · SPECT was higher than that in the conventional image. The results of this MF image with IQ · SPECT study suggest that the optimal acquisition parameter should be 56 beats/view in 8 frames per R-R interval, and the optimal reconstruction parameters should be subset 3 and iteration 14.

  17. Regions of the human brain affected during a liquid-meal taste perception in the fasting state: a positron emission tomography study.

    PubMed

    Gautier, J F; Chen, K; Uecker, A; Bandy, D; Frost, J; Salbe, A D; Pratley, R E; Lawson, M; Ravussin, E; Reiman, E M; Tataranni, P A

    1999-11-01

    The sensation of taste provides reinforcement for eating and is of possible relevance to the clinical problem of obesity. Positron emission tomography (PET) was used to explore regions of the brain that were preferentially affected during the taste perception of a liquid meal by 11 right-handed, lean men in the fasting state. After subjects had fasted for 36 h, 2 measurements of regional cerebral blood flow (rCBF) obtained immediately after subjects retained and swallowed 2 mL of a flavored liquid meal (the taste condition) were compared with 2 measurements of rCBF obtained immediately after subjects retained and swallowed 2 mL of water (the baseline condition). Compared with the baseline condition, taste was associated with increased rCBF (P < 0.005) in the left dorsolateral prefrontal cortex and superior temporal gyrus; the right ventrolateral prefrontal cortex, supramarginal gyrus, and anterior thalamus; and bilaterally in the hippocampal formation, posterior cingulate, midbrain, occipital cortex, and cerebellum. Taste was also associated with decreased rCBF (P < 0.005) in the right dorsolateral prefrontal cortex, superior temporal gyrus, and supplementary motor area, and bilaterally in the medial prefrontal cortex and inferior parietal lobule. This exploratory study provides additional evidence that the temporal cortex, thalamus, cingulate cortex, caudate, and hippocampal formation are preferentially affected by taste stimulation. The asymmetric pattern of activity in the dorsolateral prefrontal cortex and superior temporal gyrus may contribute to the taste perception of a liquid meal perceived as pleasant. Additional studies are required to determine how these regions are affected in patients with obesity or anorexia.

  18. 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

    2009-06-07

    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.

  19. 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.

  20. Quantitative imaging of neuroinflammation in human white matter: a positron emission tomography study with translocator protein 18 kDa radioligand, [18F]-FEPPA.

    PubMed

    Suridjan, Ivonne; Rusjan, Pablo M; Kenk, Miran; Verhoeff, Nicolaas Paul L G; Voineskos, Aristotle N; Rotenberg, David; Wilson, Alan A; Meyer, Jeffrey H; Houle, Sylvain; Mizrahi, Romina

    2014-11-01

    The ability to quantify translocator protein 18 kDa (TSPO) in white matter (WM) is important to understand the role of neuroinflammation in neurological disorders with WM involvement. This article aims to extend the utility of TSPO imaging in WM using a second-generation radioligand, [18F]-FEPPA, and high-resolution research tomograph (HRRT) positron emission tomography (PET) camera system. Four WM regions of interests (WM-ROI), relevant to the study of aging and neuroinflammatory diseases, were examined. The corpus callosum, cingulum bundle, superior longitudinal fasciculus, and posterior limb of internal capsule were delineated automatically onto subject's T1 -weighted magnetic resonance image using a diffusion tensor imaging-based WM template. The TSPO polymorphism (rs6971) stratified individuals to three genetic groups: high-affinity binders (HAB), mixed-affinity binders (MAB), and low-affinity binders. [18F]-FEPPA PET scans were acquired on 32 healthy subjects and analyzed using a full kinetic compartment analysis. The two-tissue compartment model showed moderate identifiability (coefficient of variation 15-19%) for [18F]-FEPPA total volume distribution (VT ) in WM-ROIs. Noise affects VT variability, although its effect on bias was small (6%). In a worst-case scenario, ≤6% of simulated data did not fit reliably. A simulation of increased TSPO density exposed minimal effect on variability and identifiability of [18F]-FEPPA VT in WM-ROIs. We found no association between age and [18F]-FEPPA VT in WM-ROIs. The VT values were 15% higher in HAB than in MAB, although the difference was not statistically significant. This study provides evidence for the utility and limitations of [18F]-FEPPA PET to measure TSPO expression in WM. © 2014 Wiley Periodicals, Inc.

  1. A rodent model of metabolic surgery for study of type 2 diabetes and positron emission tomography scanning of beta cell mass

    PubMed Central

    Inabnet, William B.; Milone, Luca; Korner, Judith; Durak, Evren; Ahmed, Leaque; Pomrantz, Jill; Harris, Paul E.; Bessler, Marc

    2013-01-01

    Background Type 2 diabetes mellitus is a worldwide healthcare problem with major socioeconomic implications. Metabolic surgical procedures have been shown to improve diabetes, but the mechanism of action is poorly understood. The Goto-Kakizaki (GK) rodent is a type 2 diabetic animal model that is ideally situated for studying the effect of surgery on diabetes; however, the operative mortality is high. The aim of this study was to describe the operative technique, improvements in perioperative management, and the technique of micro-positron emission tomography (PET) scanning of the β-cell mass in GK rodents. Methods A total of 53 GK rats were divided into 1 of 3 operative groups: sham, sleeve gastrectomy, and duodenojejunal bypass. A subset of animals underwent micro-PET scanning with [11C]-dihydrotetrabenazine to determine the vesicular monoamine transporter 2 binding index, an indicator of β-cell mass. Results The 30-day mortality in the sham and sleeve gastrectomy rodents was 0; however, 2 sleeve gastrectomy rodents developed enterocutaneous fistula and 1 developed an abscess. In the duodenojejunal bypass group, the initial mortality rate was close to 90%; however, refinements in the surgical technique and perioperative management (fluids, antibiotics, pain control) lowered the mortality rate to 60%. The surgical technique is discussed in detail. [11C]-Dihydrotetrabenazine uptake in the pancreas was demonstrated on micro-PET scanning in the sham and duodenojejunal bypass rodents. Conclusion Intensive medical management in the perioperative period and attention to the operative technique lowered the mortality. [11C]-Dihydrotetrabenazine micro-PET scanning is a feasible method for assessing the β-cell mass in GK rodents and could prove to be an important modality for evaluating β-cell performance in type 2 diabetes. PMID:19136315

  2. 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

  3. 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.

  4. 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…

  5. 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…

  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. 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.

  8. Differential brain processing of audiovisual sexual stimuli in men: comparative positron emission tomography study of the initiation and maintenance of penile erection during sexual arousal.

    PubMed

    Miyagawa, Yasushi; Tsujimura, Akira; Fujita, Kazutoshi; Matsuoka, Yasuhiro; Takahashi, Tohru; Takao, Tetsuya; Takada, Shingo; Matsumiya, Kiyomi; Osaki, Yasuhiro; Takasawa, Masashi; Oku, Naohiko; Hatazawa, Jun; Kaneko, Shigeo; Okuyama, Akihiko

    2007-07-01

    The human male psychosexual cycle consists of four phases: excitation, plateau, orgasm, and resolution. Identification of the specific neural substrates of each phase may provide information regarding the brain's pathophysiology of sexual dysfunction. We previously analyzed regional cerebral blood flow (rCBF) with H(2)15O-positron emission tomography (PET) during the excitation phase (initiation of penile erection) induced by audiovisual sexual stimuli (AVSS) and identified activation of the cerebellar vermis, the bilateral extrastriate cortex, and right orbitofrontal cortex, suggesting a role of cognition/emotion in the excitement phase. In the present study, we analyzed rCBF of the same six healthy volunteers during the plateau phase (maintenance of penile erection) induced by AVSS and compared the results with those of the excitation phase. Penile rigidity was monitored in real time with RigiScan Plus during PET scanning. Images were analyzed by statistical parametric mapping (SPM) software, and rCBF in the amygdala, hypothalamus, anterior cingulate, and insula was measured. During the plateau phase, primary subcortical activation was noted in the right ventral putamen, indicating motivational factors in the sexual response via the limbic reward circuit. A significant increase in rCBF in the left hypothalamus was also observed during the plateau phase. The right anterior cingulate and left insula were specifically activated during the excitation phase but not during the plateau phase. These results indicate a significant role of the ventral putamen and the hypothalamus in the plateau phase and confirm that paralimbic and limbic components of the human brain differentially coordinate the sexual response in a psychosexual phase-dependent manner.

  9. Effects of surgical levels of propofol and sevoflurane anesthesia on cerebral blood flow in healthy subjects studied with positron emission tomography.

    PubMed

    Kaisti, Kaike K; Metsähonkala, Liisa; Teräs, Mika; Oikonen, Vesa; Aalto, Sargo; Jääskeläinen, Satu; Hinkka, Susanna; Scheinin, Harry

    2002-06-01

    The authors report a positron emission tomography (PET) study on humans with parallel exploration of the dose-dependent effects of an intravenous (propofol) and a volatile (sevoflurane) anesthetic agent on regional cerebral blood flow (rCBF) using quantitative and relative (Statistical Parametric Mapping [SPM]) analysis. Using H(2)(15)O, rCBF was assessed in 16 healthy (American Society of Anesthesiologists [ASA] physical status I) volunteers awake and at three escalating drug concentrations: 1, 1.5, and 2 MAC/EC(50), or specifically, at either 2, 3, and 4% end-tidal sevoflurane (n = 8), or 6, 9, and 12 microg/ml plasma concentration of propofol (n = 8). Rocuronium was used for muscle relaxation. Both drugs decreased the bispectral index and blood pressure dose-dependently. Comparison between adjacent levels showed that sevoflurane initially (0 vs. 1 MAC) reduced absolute rCBF by 36-53% in all areas, then (1 vs. 1.5 MAC) increased rCBF in the frontal cortex, thalamus, and cerebellum (7-16%), and finally (1.5 vs. 2 MAC) caused a dual effect with a 23% frontal reduction and a 38% cerebellar increase. In the propofol group, flow was also initially reduced by 62-70%, with minor further effects. In the SPM analysis of the "awake to 1 MAC/EC(50)" step, both anesthetic agents reduced relative rCBF in the cuneus, precuneus, posterior limbic system, and the thalamus or midbrain; additionally, propofol reduced relative rCBF in the parietal and frontal cortices. Both anesthetic agents caused a global reduction of rCBF (propofol > sevoflurane) at the 1 MAC/EC(50) level. The effect was maintained at higher propofol concentrations, whereas 2 MAC sevoflurane caused noticeable flow redistribution. Despite the marked global changes, SPM analysis enabled detailed localization of regions with the greatest relative decreases.

  10. Coronary vasodilation is impaired in both hypertrophied and nonhypertrophied myocardium of patients with hypertrophic cardiomyopathy: A study with nitrogen-13 ammonia and positron emission tomography

    SciTech Connect

    Camici, P.; Chiriatti, G.; Lorenzoni, R.; Bellina, R.C.; Gistri, R.; Italiani, G.; Parodi, O.; Salvadori, P.A.; Nista, N.; Papi, L. )

    1991-03-15

    To assess regional coronary reserve in hypertrophic cardiomyopathy, regional myocardial blood flow was measured in 23 patients with hypertrophic cardiomyopathy and 12 control subjects by means of nitrogen-13 ammonia and dynamic positron emission tomography. In patients with hypertrophic cardiomyopathy at baseline study, regional myocardial blood flow was 1.14 +/- 0.43 ml/min per g in the hypertrophied (20 +/- 3 mm) interventricular septum and 0.90 +/- 0.35 ml/min per g (p less than 0.05 versus septal flow) in the nonhypertrophied (10 +/- 2 mm) left ventricular free wall. These were not statistically different from the corresponding values in control subjects (1.04 +/- 0.25 and 0.91 +/- 0.21 ml/min per g, respectively, p = NS). After pharmacologically induced coronary vasodilation (dipyridamole, 0.56 mg/kg intravenously over 4 min), regional myocardial blood flow in patients with hypertrophic cardiomyopathy increased significantly less than in control subjects both in the septum (1.63 +/- 0.58 versus 2.99 +/- 1.06 ml/min per g, p less than 0.001) and in the free wall (1.47 +/- 0.58 versus 2.44 +/- 0.82 ml/min per g, p less than 0.001). In addition, patients with hypertrophic cardiomyopathy who had a history of chest pain had more pronounced impairment of coronary vasodilator reserve than did those without a history of chest pain. After dipyridamole, coronary resistance in the septum decreased by 38% in patients without a history of chest pain, but decreased by only 14% in those with such a history (p less than 0.05). Coronary resistance in the free wall decreased by 45% in patients without and by 27% in those with a history of chest pain (p = 0.06).

  11. Blocking of fatty acid amide hydrolase activity with PF-04457845 in human brain: a positron emission tomography study with the novel radioligand [11C]CURB

    PubMed Central

    Boileau, Isabelle; Rusjan, Pablo M; Williams, Belinda; Mansouri, Esmaeil; Mizrahi, Romina; De Luca, Vincenzo; Johnson, Douglas S; Wilson, Alan A; Houle, Sylvain; Kish, Stephen J; Tong, Junchao

    2015-01-01

    Positron emission tomography with [11C]CURB was recently developed to quantify fatty acid amide hydrolase (FAAH), the enzyme responsible for hydrolyzing the endocannabinoid anandamide. This study investigated the test–retest reliability of [11C]CURB as well as its in vivo specificity and the validity of the kinetic model by using the highly specific FAAH inhibitor, PF-04457845. Five healthy volunteers completed test–retest [11C]CURB scans 1 to 2 months apart and six subjects completed baseline and blocking scans on the same day after PF-04457845 (p.o.) administration (1, 4, or 20 mg; n=2 each). The composite parameter λk3 (an index of FAAH activity, λ=K1/k2) was estimated using an irreversible two-tissue compartment model with plasma input function. There were no clinically observable responses to oral PF-04457845 or [11C]CURB injection. Oral administration of PF-04457845 reduced [11C]CURB binding to a homogeneous level at all three doses, with λk3 values decreased by ⩾91%. Excellent reproducibility and good reliability (test–retest variability=9% intraclass correlation coefficient=0.79) were observed across all regions of interest investigated. Our findings suggest that λk3/[11C]CURB is a reliable, highly sensitive, and selective tool to measure FAAH activity in human brain in vivo. Moreover, PF-04457845 is a highly potent FAAH inhibitor (>95% inhibition at 1 mg) in living human brain. PMID:26082009

  12. Baseline increased 18F-fluoride uptake lesions at vertebral corners on positron emission tomography predict new syndesmophyte development in ankylosing spondylitis: a 2-year longitudinal study.

    PubMed

    Park, Eun-Kyoung; Pak, Kyoungjune; Park, Ji-Heh; Kim, Keunyoung; Kim, Seong-Jang; Kim, In-Joo; Kim, Geun-Tae; Lee, Seung-Geun

    2017-02-02

    The goal of this study was to demonstrate whether increased 18F-fluoride uptake lesions on positron emission tomography (PET) scan can predict new syndesmophyte development in patients with ankylosing spondylitis (AS). In 12 AS patients, 18F-fluoride PET and magnetic resonance imaging (MRI) was performed at baseline, and radiography was performed at baseline and the 2-year follow-up. The following data were recorded: the presence of increased 18F-fluoride uptake lesions on PET defined as an uptake greater than the uptake in the adjacent normal vertebral body; acute (type A) and advanced (type B) corner inflammatory lesions (CILs) and fat lesions on MRI; and syndesmophytes on radiography. Of 231 anterior vertebral corners without syndesmophyte at baseline, 13 type A CILs (5.5%), 2 type B CILs (0.9%), and 20 fat lesions (8.7%) on MRI and six increased fluoride uptake lesions (2.6%) on PET were observed. At the 2-year follow-up, 16 new syndesmophytes (6.9%) in eight AS patients (66.7%) occurred. New syndesmophytes developed significantly more frequently in anterior vertebral corners with increased 18F-fluoride uptake lesions (50%) or fat lesions (25%) at baseline than in those without such lesions (5.8 and 5.2%; p = 0.005 and p = 0.007, respectively). After adjusting confounding factors, baseline increased 18F-fluoride uptake lesions was independently associated with new syndesmophytes development (OR 13.8, 95% CI 1.5-124.3, p = 0.019). Fat lesions were also associated with new syndesmophytes formation. Our data suggest that 18F-fluoride PET may be applied to identify AS patients with high risk of future syndesmophyte formation.

  13. Lack of age-dependent decrease in dopamine D3 receptor availability: a [(11)C]-(+)-PHNO and [(11)C]-raclopride positron emission tomography study.

    PubMed

    Nakajima, Shinichiro; Caravaggio, Fernando; Boileau, Isabelle; Chung, Jun K; Plitman, Eric; Gerretsen, Philip; Wilson, Alan A; Houle, Sylvain; Mamo, David C; Graff-Guerrero, Ariel

    2015-11-01

    Positron emission tomography with antagonist radiotracers has showed that striatal dopamine D2/3 receptor (D2/3R) availability decreases with age. However, no study has specifically assessed whether D2/3R availability decreases with age in healthy persons as measured with agonist radiotracers. Moreover, it is unknown whether D3R availability changes with age in healthy humans. Thus, we explored the relationship between age and D2/3R availability in healthy humans using the D3 receptor (D3R)-preferential agonist radiotracer [(11)C]-(+)-PHNO (n=72, mean±s.d. age=40±15, range=18 to 73) and the antagonist [(11)C]-Raclopride (n=70, mean±s.d. age =40±14, range=18 to 73) (both, n=33). The contribution of D3R to the [(11)C]-(+)-PHNO signal varies across regions of interest; the substantia nigra and hypothalamus represent D3R-specific regions, the ventral pallidum, globus pallidus, and ventral striatum represent D2/3R-mixed regions, and the caudate and putamen represent D2 receptor (D2R)-specific regions. With [(11)C]-(+)-PHNO, a negative correlation was observed between age and nondisplaceable binding potential (BPND) in the caudate (r(70)=-0.32, P=0.005). No correlations were observed in the other regions. With [(11)C]-Raclopride, negative correlations were observed between age and BPND in the caudate (r(68)=-0.50, P<0.001), putamen (r(68)=-0.41, P<0.001), and ventral striatum (r(68)=-0.43, P<0.001). In conclusion, in contrast with the age-dependent decrease in D2R availability, these findings suggest that D3R availability does not change with age.

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

    PubMed Central

    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.

    2015-01-01

    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 15O-water followed by 11C-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 11C-radioactivity distribution across the human BBB as measured by the brain extraction ratio (ER) of 11C-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 11C-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

  15. Optimization of attenuation correction for positron emission tomography studies of thorax and pelvis using count-based transmission scans.

    PubMed

    Boellaard, R; van Lingen, A; van Balen, S C M; Lammertsma, A A

    2004-02-21

    The quality of thorax and pelvis transmission scans and therefore of attenuation correction in PET depends on patient thickness and transmission rod source strength. The purpose of the present study was to assess the feasibility of using count-based transmission scans, thereby guaranteeing more consistent image quality and more precise quantification than with fixed transmission scan duration. First, the relation between noise equivalent counts (NEC) of 10 min calibration transmission scans and rod source activity was determined over a period of 1.5 years. Second, the relation between transmission scan counts and uniform phantom diameter was studied numerically, determining the relative contribution of counts from lines of response passing through the phantom as compared with the total number of counts. Finally, the relation between patient weight and transmission scan duration was determined for 35 patients, who were scanned at the level of thorax or pelvis. After installation of new rod sources, the NEC of transmission scans first increased slightly (5%) with decreasing rod source activity and after 3 months decreased with a rate of 2-3% per month. The numerical simulation showed that the number of transmission scan counts from lines of response passing through the phantom increased with phantom diameter up to 7 cm. For phantoms larger than 7 cm, the number of these counts decreased at approximately the same rate as the total number of transmission scan counts. Patient data confirmed that the total number of transmission scan counts decreased with increasing patient weight with about 0.5% kg(-1). It can be concluded that count-based transmission scans compensate for radioactive decay of the rod sources. With count-based transmission scans, rod sources can be used for up to 1.5 years at the cost of a 50% increased transmission scan duration. For phantoms with diameters of more than 7 cm and for patients scanned at the level of thorax or pelvis, use of count

  16. NOTE: Optimization of attenuation correction for positron emission tomography studies of thorax and pelvis using count-based transmission scans

    NASA Astrophysics Data System (ADS)

    Boellaard, R.; van Lingen, A.; van Balen, S. C. M.; Lammertsma, A. A.

    2004-02-01

    The quality of thorax and pelvis transmission scans and therefore of attenuation correction in PET depends on patient thickness and transmission rod source strength. The purpose of the present study was to assess the feasibility of using count-based transmission scans, thereby guaranteeing more consistent image quality and more precise quantification than with fixed transmission scan duration. First, the relation between noise equivalent counts (NEC) of 10 min calibration transmission scans and rod source activity was determined over a period of 1.5 years. Second, the relation between transmission scan counts and uniform phantom diameter was studied numerically, determining the relative contribution of counts from lines of response passing through the phantom as compared with the total number of counts. Finally, the relation between patient weight and transmission scan duration was determined for 35 patients, who were scanned at the level of thorax or pelvis. After installation of new rod sources, the NEC of transmission scans first increased slightly (5%) with decreasing rod source activity and after 3 months decreased with a rate of 2 3% per month. The numerical simulation showed that the number of transmission scan counts from lines of response passing through the phantom increased with phantom diameter up to 7 cm. For phantoms larger than 7 cm, the number of these counts decreased at approximately the same rate as the total number of transmission scan counts. Patient data confirmed that the total number of transmission scan counts decreased with increasing patient weight with about 0.5% kg-1. It can be concluded that count-based transmission scans compensate for radioactive decay of the rod sources. With count-based transmission scans, rod sources can be used for up to 1.5 years at the cost of a 50% increased transmission scan duration. For phantoms with diameters of more than 7 cm and for patients scanned at the level of thorax or pelvis, use of count

  17. Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography.

    PubMed

    Schlünzen, L; Cold, G E; Rasmussen, M; Vafaee, M S

    2006-03-01

    In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus. Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, aO PET scan was performed. Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus. Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2-1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.

  18. 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

  19. Positron emission tomography reveals a leiomyosarcoma causing proteinuria.

    PubMed

    Hegner, B; Krakamp, B; Hedde, J P; Brockmann, M; Weber, M; Schulze-Lohoff, E

    2003-08-01

    Obstruction of the renal veins may result in proteinuria and is frequently caused by thrombosis or tumorous processes. Since thrombosis and malignancy may occur simultaneously in the venous outflow of the kidneys, search for an underlying intraluminal tumor may be impeded by extensive thrombosis in the lumen of renal and caval veins. We report the case of a 30-year-old man with moderate proteinuria which was caused by an obstructing process of the vena cava inferior and the renal veins. While the obstructive mass was initially misdiagnosed as thrombosis, positron emission tomography helped to reveal the tumorous character of the lesion and fine-needle biopsy allowed rapid diagnosis of a leiomyosarcoma originating from the caval or renal veins. We conclude that undelayed diagnosis of the cause of renal and caval vein obstruction is facilitated by early positron emission tomography and subsequent fine-needle biopsy to identify possible tumorous lesions.

  20. Reconstruction of Emission Tomography Data Using Origin Ensembles

    PubMed Central

    Sitek, Arkadiusz

    2011-01-01

    A new statistical reconstruction method based on origin ensembles (OE) for emission tomography (ET) is examined. Using a probability density function (pdf) derived from first principles, an ensemble expectation of numbers of detected event origins per voxel is determined. These numbers divided by sensitivities of voxels and acquisition time provide OE estimates of the voxel activities. The OE expectations are shown to be the same as expectations calculated using the complete–data space. The properties of the OE estimate are examined. It is shown that OE estimate approximates maximum likelihood (ML) estimate for conditions usually achieved in practical applications in emission tomography. Three numerical experiments with increasing complexity are used to validate theoretical findings and demonstrate similarities of ML and OE estimates. Recommendations for achieving improved accuracy and speed of OE reconstructions are provided. PMID:21147594

  1. 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.

  2. Magnetic resonance imaging and positron emission tomography of band heterotopia.

    PubMed

    Miura, K; Watanabe, K; Maeda, N; Matsumoto, A; Kumagai, T; Ito, K; Kato, T

    1993-01-01

    A case of band heterotopia was reported with findings of positron emission tomography (PET). The patient was an 8-year-old girl who had mild mental retardation and intractable partial epilepsy. Her MRI showed another diffuse layer of gray matter underlying the normal-looking cortex and separated from it by an apparently normal layer of white matter. PET scan with [18F]fluorodeoxyglucose revealed that band heterotopia had the same degree of glucose metabolism as that of the overlying cortex.

  3. Technology related parameters affecting quantification in positron emission tomography imaging.

    PubMed

    Visvikis, D; Turzo, A; Bizais, Y; Cheze-Le Rest, C

    2004-07-01

    Some of the issues associated with positron emission tomography (PET) technology which still pose challenges for the recovery of quantitative images are discussed. Through these issues reference to what is today considered as the 'gold standard' in quantitative PET imaging is also presented. A brief comparison of 2-D and 3-D PET is given, together with a short discussion of combined PET/CT imaging devices.

  4. Current and future technological trends in positron emission tomography.

    PubMed

    Karp, J S; Freifelder, R

    1992-04-01

    Current trends in positron emission tomography (PET) instrumentation are examined, with an emphasis on providing information suitable to the prospective PET user. Basic principles underlying PET are explained and information on performance measurements, techniques, and quantitation are given in order to allow the user to compare and contrast different types of PET scanners. These scanner designs are described. Specific examples are given and the combination of PET with other modalities is discussed.

  5. Revisiting stopping rules for iterative methods used in emission tomography.

    PubMed

    Guo, Hongbin; Renaut, Rosemary A

    2011-07-01

    The expectation maximization algorithm is commonly used to reconstruct images obtained from positron emission tomography sinograms. For images with acceptable signal to noise ratios, iterations are terminated prior to convergence. A new quantitative and reproducible stopping rule is designed and validated on simulations using a Monte-Carlo generated transition matrix with a Poisson noise distribution on the sinogram data. Iterations are terminated at the solution which yields the most probable estimate of the emission densities while matching the sinogram data. It is more computationally efficient and more accurate than the standard stopping rule based on the Pearson's χ(2) test.

  6. A combined accelerator mass spectrometry-positron emission tomography human microdose study with 14C- and 11C-labelled verapamil

    PubMed Central

    Wagner, Claudia C; Simpson, Marie; Zeitlinger, Markus; Bauer, Martin; Karch, Rudolf; Abrahim, Aiman; Feurstein, Thomas; Schütz, Matthias; Kletter, Kurt; Müller, Markus; Lappin, Graham; Langer, Oliver

    2013-01-01

    Background and Objective In microdose studies, the pharmacokinetic (PK) profile of a drug in blood after administration of a dose up to 100 μg is measured with sensitive analytical techniques, such as accelerator mass spectrometry (AMS). As most drugs exert their effect in tissue rather than blood, methodology is needed for extending PK analysis to different tissue compartments. In the present study, we combined, for the first time, AMS analysis with positron emission tomography (PET) in order to determine the PK profile of the model drug verapamil in plasma and brain of humans. In order to assess PK dose-linearity of verapamil, data were acquired and compared after administration of an intravenous (iv) microdose and an iv microdose dosed concomitantly with an oral therapeutic dose. Methods Six healthy male volunteers received an iv microdose (0.05 mg) (period 1) and an iv microdose dosed concomitantly with an oral therapeutic dose (80 mg) of verapamil (period 2) in a randomized, cross-over, two-period study design. The iv dose was a mixture of (R/S)-[14C]verapamil and (R)-[11C]verapamil and the oral dose was unlabelled racemic verapamil. Brain distribution of radioactivity was measured with PET whereas plasma PK of (R)- and (S)-verapamil was determined with AMS. PET data were analyzed by kinetic modeling to estimate the rate constants for transfer of radioactivity across the blood-brain barrier. Results Most PK parameters of (R)- and (S)-verapamil as well as parameters describing exchange of radioactivity between plasma and brain (K1=0.030±0.003 and 0.031±0.005 mL·mL−1·min−1 and k2=0.099±0.006 and 0.095±0.008 min−1 for period 1 and 2, respectively) were not statistically different between the two periods although there was a trend for non-linear kinetics for the (R)-enantiomer. On the other hand, all PK parameters (except for t1/2) differed significantly between the (R)- and (S)-enantiomers for both periods. Cmax, AUC(0-24) and AUC(0-inf) were higher

  7. 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

  8. Pravastatin stimulates angiogenesis in a murine hindlimb ischemia model: a positron emission tomography imaging study with (64)Cu-NOTA-TRC105.

    PubMed

    Orbay, Hakan; Hong, Hao; Koch, Jill M; Valdovinos, Hector F; Hacker, Timothy A; Theuer, Charles P; Barnhart, Todd E; Cai, Weibo

    2013-01-01

    In this study, (64)Cu-NOTA-TRC105 (TRC105 is an anti-CD105 monoclonal antibody that binds to both human and murine CD105) positron emission tomography (PET) was used to assess the response to pravastatin treatment in a murine model of peripheral artery disease (PAD). Hindlimb ischemia was induced by ligation of the right femoral arteries in BALB/c mice under anesthesia, and the left hindlimb served as an internal control. Mice in the treatment group were given intraperitoneal pravastatin daily until the end of the study, whereas the animals in the control group were injected with 0.9% sodium chloride solution. Laser Doppler imaging showed that blood flow in the ischemic hindlimb plummeted to ~20% of the normal level after surgery, and gradually recovered to near normal level on day 10 in the treatment group and on day 20 in the control group. Angiogenesis was non-invasively monitored and quantified with (64)Cu-NOTA-TRC105 PET on postoperative days 3, 10, 17, and 24. Tracer uptake at 48 h post-injection in the ischemic hindlimb in the treatment group was significantly higher than that of the control group on day 10 (20.5 ± 1.9 %ID/g vs 11.4 ± 1.5 %ID/g), suggesting increased CD105 expression and higher level of angiogenesis upon pravastatin treatment, and gradually decreased to background levels in both groups (4.9 ± 0.8 %ID/g vs 3.4 ± 1.9 %ID/g on day 24). The in vivo PET data correlated well with ex vivo biodistribution studies performed on day 24. Increased CD105 expression on days 3 and 10 following ischemia was further confirmed by immunofluorescence staining. Taken together, our results indicated that (64)Cu-NOTA-TRC105 PET is a suitable and non-invasive method to monitor the angiogenesis and therapeutic response in PAD, which can also be utilized for non-invasive evaluation of other pro-angiogenic/anti-angiogenic drugs in other cardiovascular diseases and cancer.

  9. Synthesis and positron emission tomography studies of C-11-labeled isotopomers and metabolites of GTS-21, a partial alpha7 nicotinic cholinergic agonist drug.

    PubMed

    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

    2007-07-01

    (3E)-3-[(2,4-dimethoxyphenyl)methylene]-3,4,5,6-tetrahydro-2,3'-bipyridine (GTS-21), a partial alpha7 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. We labeled GTS-21 in two different positions with carbon-11 ([2-methoxy-(11)C]GTS-21 and [4-(11)C]GTS-21) along with two corresponding demethylated metabolites ([2-methoxy-(11)C]4-OH-GTS-21 and [4-methoxy-(11)C]2-OH-GTS-21) for pharmacokinetic studies in baboons and mice with positron emission tomography (PET). Both [2-(11)C]GTS-21 and [4-methoxy-(11)C]GTS-21 showed similar initial high rapid uptake in baboon brain, peaking from 1 to 3.5 min (0.027-0.038%ID/cc) followed by rapid clearance (t(1/2)<15 min), resulting in low brain retention by 30 min. However, after 30 min, [2-methoxy-(11)C]GTS-21 continued to clear while [4-methoxy-(11)C]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-(11)C]2-OH-GTS-21 (the labeled metabolite of [4-methoxy-(11)C]GTS-21) relative to [2-methoxy-(11)C]4-OH-GTS-21 (the labeled metabolite of [2-methoxy-(11)C]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. The major findings are as follows: (a) extremely rapid uptake and clearance of [2-methoxy-(11)C]GTS-21 from the brain, which may need to be considered in developing optimal dosing of GTS-21 for patients, and (b) 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

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

    PubMed

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

    2014-10-01

    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. 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. 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. 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.

  11. Trends in radiation protection of positron emission tomography/computed tomography imaging.

    PubMed

    Alenezi, A; Soliman, K

    2015-06-01

    Over the past decade, the number of positron emission tomography/computed tomography (PET/CT) imaging procedures has increased substantially. This imaging technique provides accurate functional and anatomical information, particularly for oncological applications. Separately, both PET and CT are considered as high-dose imaging modalities. With the increased use of PET/CT, one could expect an increase in radiation doses to staff and patients. As such, major efforts have been made to reduce radiation dose in PET/CT facilities. Variations in working techniques have made it difficult to compare published results. This study aimed to review the literature on proposed methods to reduce patient and staff dose in clinical PET/CT imaging. A brief overview of some published information on staff and patient doses will be analysed and presented. Recent trends regarding radiation protection in PET/CT imaging will be discussed, and practical recommendations for reducing radiation doses to staff and patients will be discussed and summarised. Generally, the CT dose component is often higher in magnitude than the dose from PET alone; as such, focusing on CT dose reduction will decrease the overall patient dose in PET/CT imaging studies. The following factors should be considered in order to reduce the patient's dose from CT alone: proper justification for ordering contrast-enhanced CT; use of automatic exposure control features; use of adaptive statistical iterative reconstruction algorithms; and optimisation of scan parameters, especially scan length. The PET dose component can be reduced by administration of lower activity to the patient, optimisation of the workflow, and appropriate use of protective devices and engineered systems. At the international level, there is wide variation in work practices among institutions. The current observed trends are such that the annual dose limits for radiation workers in PET/CT imaging are unlikely to be exceeded.

  12. Does positron emission tomography/computed tomography change management in colorectal cancer?

    PubMed

    Falconer, Rachel; Connor, Saxon; Balasingam, Adrian; Eglinton, Tim

    2016-10-27

    Positron emission tomography/computed tomography (PET/CT) is used pre-operatively in patients with metastatic or recurrent colorectal cancer to identify those who have potentially curative disease. However, a recent randomized trial questioned the added benefit of PET/CT over conventional imaging in patients with liver metastases. The aim of this study was to determine the proportion of patients with colorectal cancer in whom PET/CT altered surgical management, in a single tertiary centre. This was a retrospective study of all patients with colorectal cancer who had a PET/CT for colorectal cancer, funded by the Canterbury District Health Board between 2010 and 2014. Some 111 PET/CT scans were performed on 105 patients. A total of 38% of PET/CT were for patients with known or suspected liver metastases, 23% for suspected local recurrence and 18% for known or suspected lung metastases. Five scans were for post-operative patients with a rising carcinoembryonic antigen and no attributable source on conventional imaging. PET/CT identified additional extrahepatic sites of disease in 19 of 111 (17%) scans in patients deemed to have potentially operable disease. Overall, PET/CT altered surgical management following six of 42 (14%) scans for patients with liver metastases, four of 20 (20%) scans for patients with lung metastases and six of 26 (23%) scans for patients with local recurrence. PET/CT remains a useful adjunct to conventional imaging in the pre-operative workup of patients with colorectal cancer. © 2016 Royal Australasian College of Surgeons.

  13. Predicting exercise capacity after lobectomy by single photon emission computed tomography and computed tomography.

    PubMed

    Nagamatsu, Yoshinori; Sueyoshi, Susumu; Sasahara, Hiroko; Oka, Yousuke; Kumazoe, Hiroyuki; Mitsuoka, Masahiro; Akagi, Yoshito

    2016-09-01

    This study compared the prediction of postoperative exercise capacity by employing lung perfusion scintigraphy images obtained with single photon emission computed tomography together with computed tomography (SPECT/CT) versus the common method of counting subsegments (SC method). In 18 patients scheduled for lobectomy, predicted postoperative maximum oxygen uptake per kilogram body weight ([Formula: see text]) was calculated by the SPECT/CT and SC methods. Correlations were examined between the [Formula: see text] predicted by SPECT/CT or the SC method, and the actual [Formula: see text] measured at 2 weeks (mean 15.4 ± 1.5 days) and 1 month (mean 29.1 ± 0.75 days) after surgery to determine whether SPECT/CT was more accurate than SC for predicting postoperative exercise capacity. There was a significant positive correlation between the [Formula: see text] predicted by SPECT/CT and the actual value at 2 weeks (r = 0.802, p < 0.0001) or 1 month (r = 0.770, p < 0.0001). There was also a significant positive correlation between the [Formula: see text] predicted by SC and the actual value at 2 weeks (r = 0.785, p < 0.0001) or 1 month (r = 0.784, p < 0.0001). This study showed that both SPECT/CT and the SC method were useful for predicting postoperative [Formula: see text] in the clinical setting.

  14. Imaging in breast cancer: Single-photon computed tomography and positron-emission tomography

    PubMed Central

    Bénard, François; Turcotte, Éric

    2005-01-01

    Although mammography remains a key imaging method for the early detection and screening of breast cancer, the overall accuracy of this test remains low. Several radiopharmaceuticals have been proposed as adjunct imaging methods to characterize breast masses by single-photon-emission computed tomography (SPECT) and positron-emission tomography (PET). Useful in characterizing indeterminate palpable masses and in the detection of axillary metastases, these techniques are insufficiently sensitive to detect subcentimetric tumor deposits. Their role in staging nodal involvement of the axillary areas therefore currently remains limited. Several enzymes and receptors have been targeted for imaging breast cancers with PET. [18F]Fluorodeoxyglucose is particularly useful in the detection and staging of recurrent breast cancer and in assessing the response to chemotherapy. Several other ligands targeting proliferative activity, protein synthesis, and hormone and cell-membrane receptors may complement this approach by providing unique information about biological characteristics of breast cancer across primary and metastatic tumor sites. PMID:15987467

  15. Effects of metabolite correction for arterial input function on quantitative receptor images with 11C-flumazenil in clinical positron emission tomography studies.

    PubMed

    Okazawa, Hidehiko; Yamauchi, Hiroshi; Sugimoto, Kanji; Magata, Yasuhiro; Kudo, Takashi; Yonekura, Yoshiharu

    2004-01-01

    To evaluate the effect of inputs estimated from different methods for metabolite correction on binding potential (BP) of C-flumazenil (FMZ). Five healthy volunteers underwent C-FMZ positron emission tomography. Arterial blood was sampled to obtain plasma radioactivity and metabolite fraction, followed by estimation of input functions with several methods. Binding potential images for different input functions and that using the noninvasive graphic method were calculated. Images of standardized uptake value (SUV) with different acquisition times were also compared. Binding potential images calculated from arterial inputs were almost equivalent, and regional values were not significantly different irrespective of methods for metabolite correction as well as the noninvasive graphic plot method. Standardized uptake value images showed less contrast compared with quantitative BP images, and the regional values varied depending on scan time. Statistical parametric mapping analysis showed significant regional differences between BP and SUV images. Binding potential images were equivalent irrespective of calculation methods; however, SUV was not appropriate for quantitative evaluation.

  16. Longitudinal Partial Volume Correction in 2-[18F]-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography Studies of Alzheimer Disease.

    PubMed

    Malpas, Charles B; Saling, Michael M; Velakoulis, Dennis; Desmond, Patricia; Hicks, Rodney J; OʼBrien, Terence J

    2015-01-01

    To investigate partial volume correction (PVC) of 2-[F]-fluoro-2-deoxy-D-glucose positron emission tomography in Alzheimer disease in a longitudinal context. A total of 115 participants were included, including 55 controls, 53 patients with mild cognitive impairment, and 7 patients with dementia of the Alzheimer type. Imaging was performed at baseline and 24 months. Partial volume corrected vs uncorrected rates of longitudinal change were compared for mesial temporal and cortical regions of interest. Partial volume correction increased apparent uptake, and this effect was greater at 24 months compared with baseline. Partial volume correction decreased the rate of decline, causing an apparent increase in uptake at 24 months compared with baseline. This effect was correlated with the structural atrophy. These findings suggest that applying PVC in a longitudinal context in Alzheimer disease might produce unpredictable results. Accordingly, both PVC corrected and uncorrected data should be reported to ensure that the results are physiologically plausible.

  17. 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.

  18. Improved differentiation of benign and malignant breast tumors with multiparametric 18fluorodeoxyglucose positron emission tomography magnetic resonance imaging: a feasibility study.

    PubMed

    Pinker, Katja; Bogner, Wolfgang; Baltzer, Pascal; Karanikas, Georgios; Magometschnigg, Heinrich; Brader, Peter; Gruber, Stephan; Bickel, Hubert; Dubsky, Peter; Bago-Horvath, Zsuzsanna; Bartsch, Rupert; Weber, Michael; Trattnig, Siegfried; Helbich, Thomas H

    2014-07-01

    To assess whether multiparametric (18)fluorodeoxyglucose positron emission tomography magnetic resonance imaging (MRI) (MP (18)FDG PET-MRI) using dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted imaging (DWI), three-dimensional proton MR spectroscopic imaging (3D (1)H-MRSI), and (18)FDG-PET enables an improved differentiation of benign and malignant breast tumors. Seventy-six female patients (mean age, 55.7 years; range, 25-86 years) with an imaging abnormality (BI-RADS 0, 4-5) were included in this Institutional Review Board (IRB)-approved study. Patients underwent fused PET-MRI of the breast with (18)FDG-PET/CT and MP MRI at 3T. The likelihood of malignancy was assessed for all single parameters, for MP MRI with two/three parameters, and for MP (18)FDG PET-MRI. Histopathology was used as the standard of reference. Appropriate statistical tests were used to assess sensitivity, specificity, and diagnostic accuracy for each assessment combination. There were 53 malignant and 23 benign breast lesions. MP (18)FDG PET-MRI yielded a significantly higher area under the cure (AUC) of 0.935 than DCE-MRI (AUC, 0.86; P = 0.044) and the combination of DCE-MRI and another parameter (AUC, 0.761-0.826; P = 0.013-0.020). MP (18)FDG PET-MRI showed slight further improvement to MP MRI with three parameters (AUC, 0.925; P = 0.317). Using MP (18)FDG PET-MRI there would have been a reduction of the unnecessary breast biopsies recommended by MP imaging with one or two parameters (P = 0.002-0.011). This feasibility study shows that MP (18)FDG PET-MRI enables an improved differentiation of benign and malignant breast tumors when several MRI and PET parameters are combined. MP (18)FDG PET-MRI may lead to a reduction in unnecessary breast biopsies. ©2014 American Association for Cancer Research.

  19. Long-term estrogen therapy and 5-HT(2A) receptor binding in postmenopausal women; a single photon emission tomography (SPET) study.

    PubMed

    Compton, J; Travis, M J; Norbury, R; Erlandsson, K; van Amelsvoort, T; Daly, E; Waddington, W; Matthiasson, P; Eersels, J L H; Whitehead, M; Kerwin, R W; Ell, P J; Murphy, D G M

    2008-01-01

    Variation in estrogen level is reported by some to affect brain maturation and memory. The neurobiological basis for this may include modulation of the serotonergic system. No neuroimaging studies have directly examined the effect of extended estrogen therapy (ET), on the 5-HT(2A) receptor in human brain. We investigated the effect of long-term ET on cortical 5-HT(2A) receptor availability in postmenopausal women. In a cross-sectional study, we compared cortical 5-HT(2A) receptor availability in 17 postmenopausal ERT-naive women and 17 long-term oophorectomised estrogen-users, age- and IQ-matched using single photon emission tomography and the selective 5-HT(2A) receptor ligand (123)I-5-I-R91150. Also, we used the Revised Wechsler Memory Scale to relate memory function to 5-HT(2A) receptor availability. Never-users had significantly higher 5-HT(2A) receptor availability than estrogen-users in hippocampus (1.17 vs. 1.11, respectively, p=0.02), although this did not remain significant after correction for multiple comparisons. Hippocampal 5-HT(2A) receptor availability correlated negatively with verbal and general memory and delayed recall (r=-0.45, p=0.01; r=-0.40, p=0.02; r=-0.36, p=0.04). Right superior temporal 5-HT(2A) receptor availability correlated negatively with verbal memory (r=-0.36, p=0.04). In estrogen-users, receptor availability correlated negatively with verbal and general memory (r=-0.70, p=0.002; r=-0.69, p=0.002); and in never-users, receptor availability negatively correlated with attention and concentration (r=-0.54, p=0.02). Long-term ET may be associated with lower 5-HT(2A) receptor availability in hippocampus. This may reflect increased activity within the serotonergic pathway leading to down-regulation of post-synaptic receptor. Also, increased availability of the 5-HT(2A) receptor in hippocampus is associated with poorer memory function.

  20. 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.

  1. C-Arm Computed Tomography Compared With Positron Emission Tomography/Computed Tomography for Treatment Planning Before Radioembolization

    SciTech Connect

    Becker, Christoph Waggershauser, Tobias; Tiling, Reinhold; Weckbach, Sabine; Johnson, Thorsten; Meissner, Oliver; Klingenbeck-Regn, Klaus; Reiser, Maximilian; Hoffmann, Ralf Thorsten

    2011-06-15

    The purpose of this study was to determine whether rotational C-arm computed tomography (CT) allows visualization of liver metastases and adds relevant information for radioembolization (RE) treatment planning. Technetium angiography, together with C-arm CT, was performed in 47 patients to determine the feasibility for RE. C-arm CT images were compared with positron emission tomography (PET)/CT images for the detection of liver tumors. The images were also rated according one of the following three categories: (1) images that provide no additional information compared with DSA alone; (2) images that do provide additional information compared with DSA; and (2) images that had an impact on eligibility determination for and planning of the RE procedure. In all patients, 283 FDG-positive liver lesions were detected by PET. In venous contrast-phase CT, 221 (78.1%) and 15 (5.3%) of these lesions were either hypodense or hyperdense, respectively. In C-arm CT, 103 (36.4%) liver lesions were not detectable because they were outside of either the field of view or the contrast-enhanced liver segment. Another 25 (8.8%) and 98 (34.6%) of the liver lesions were either hyperdense or presented primarily as hypodense lesions with a rim enhancement, respectively. With PET/CT as the standard of reference, venous CT and C-arm CT failed to detect 47 (16.6%) and 57 (20.1%) of all liver lesions, respectively. For RE planning, C-arm CT provided no further information, provide some additional information, or had an impact on the procedure in 20 (42.5%), 15 (31.9%) and 12 (25.6%) of patients, respectively. We conclude that C-arm CT may add decisive information in patients scheduled for RE.

  2. Routine positron emission tomography and positron emission tomography/computed tomography in melanoma staging with positive sentinel node biopsy is of limited benefit.

    PubMed

    Constantinidou, Anastasia; Hofman, Michael; O'Doherty, Michael; Acland, Katharine M; Healy, Ciaran; Harries, Mark

    2008-02-01

    Positron emission tomography (PET) is increasingly used for the staging and management of melanoma. The aim of this study was to evaluate the role of PET or PET/ computed tomography (CT) as a routine procedure in patients with positive sentinel node biopsy (SNB). Thirty patients with melanoma of Breslow thickness greater than 1 mm who had PET or PET/CT scans performed within 100 days after a positive SNB were reviewed retrospectively. Two patients (6%) had a positive PET scan, none of which were melanoma related. The first patient had a synchronous neuroendocrine thyroid tumour and the second patient had increased uptake in the chest wall, which proved to be old trauma. Lymph node dissection was positive in five cases (16%). With a median follow-up of 24 months, 21 patients remained disease free. In none of the 30 cases did the early PET scan after a positive SNB alter subsequent melanoma management. The role of PET scanning soon after a positive sentinel node biopsy seems to be of limited benefit. It is questionable whether any imaging is beneficial at this stage. The results of this review suggest that PET scanning might not be indicated for this group of patients.

  3. 18F-fluorodeoxyglucose positron-emission tomography-computed tomography to diagnose recurrent cancer

    PubMed Central

    You, J J; Cline, K J; Gu, C-S; Pritchard, K I; Dayes, I S; Gulenchyn, K Y; Inculet, R I; Dhesy-Thind, S K; Freeman, M A; Chan, A M; Julian, J A; Levine, M N

    2015-01-01

    Background: Sometimes the diagnosis of recurrent cancer in patients with a previous malignancy can be challenging. This prospective cohort study assessed the clinical utility of 18F-fluorodeoxyglucose positron-emission tomography-computed tomography (18F-FDG PET-CT) in the diagnosis of clinically suspected recurrence of cancer. Methods: Patients were eligible if cancer recurrence (non-small-cell lung (NSCL), breast, head and neck, ovarian, oesophageal, Hodgkin's or non-Hodgkin's lymphoma) was suspected clinically, and if conventional imaging was non-diagnostic. Clinicians were asked to indicate their management plan before and after 18F-FDG PET-CT scanning. The primary outcome was change in planned management after 18F-FDG PET-CT. Results: Between April 2009 and June 2011, 101 patients (age, median 65 years; 55% female) were enroled from four cancer centres in Ontario, Canada. Distribution by primary tumour type was: NSCL (55%), breast (19%), ovarian (10%), oesophageal (6%), lymphoma (6%), and head and neck (4%). Of the 99 subjects who underwent 18F-FDG PET-CT, planned management changed after 18F-FDG PET-CT in 52 subjects (53%, 95% confidence interval (CI), 42–63%); a major change in plan from no treatment to treatment was observed in 38 subjects (38%, 95% CI, 29–49%), and was typically associated with 18F-FDG PET-CT findings that were positive for recurrent cancer (37 subjects). After 3 months, the stated post-18F-FDG PET-CT management plan was actually completed in 88 subjects (89%, 95% CI, 81–94%). Conclusion: In patients with suspected cancer recurrence and conventional imaging that is non-diagnostic, 18F-FDG PET-CT often provides new information that leads to important changes in patient management. PMID:25942398

  4. Accuracy of 18F fluorodeoxyglucose positron emission tomography/computed tomography in staging of pediatric sarcomas.

    PubMed

    Tateishi, Ukihide; Hosono, Ako; Makimoto, Atsushi; Sakurada, Aine; Terauchi, Takashi; Arai, Yasuaki; Imai, Yutaka; Kim, Euishin Edmund

    2007-09-01

    The present study was conducted to clarify the diagnostic accuracy of 18F-fluoro-2-deoxy-D-glucose (18FDG) positron emission tomography (PET)/computed tomography (CT) in the staging in pediatric sarcomas. Fifty pediatric patients with histologically proven sarcomas who underwent 18FDG PET/CT before treatment were evaluated retrospectively for the detection of nodal and distant metastases. Diagnostic accuracy of 18FDG PET/CT in detecting nodal and distant metastases was compared with that of 18FDG PET and conventional imaging (CI). The images were reviewed and a diagnostic consensus was reached by 3 observers. REFERENCE standard was histologic examination in 15 patients and confirmation of an obvious progression in size of the lesions on follow-up examinations. Nodal metastasis was correctly assessed in 48 patients (96%) with PET/CT, in contrast to 43 patients (86%) with PET, and 46 patients (92%) with CI. Diagnostic accuracies of nodal metastasis in 3 modalities were similar. Using PET/CT, distant metastasis was correctly assigned in 43 patients (86%), whereas interpretation based on PET alone or CI revealed distant metastasis in 33 patients (66%) and 35 patients (70%), respectively. Diagnostic accuracy of distant metastasis with PET/CT was significantly higher than that of PET (P=0.002) or CI (P=0.008). False negative results regarding distant metastasis by PET/CT in 7 patients (14%) were caused by subcentimetric lesions (n=4), bone marrow lesion (n=2), and soft tissue lesions (n=1). PET/CT is more accurate and probably more cost-effective than PET alone or CI regarding distant metastasis in pediatric sarcomas.

  5. 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.

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

    PubMed

    Rodriguez-Vieitez, Elena; Ni, Ruiqing; Gulyás, Balázs; Tóth, Miklós; Häggkvist, Jenny; Halldin, Christer; Voytenko, Larysa; Marutle, Amelia; Nordberg, Agneta

    2015-06-01

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

  7. 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 Central

    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

  8. Cerebral hemodynamic disturbance in dural arteriovenous fistula with retrograde leptomeningeal venous drainage: a prospective study using (123)I-iodoamphetamine single photon emission computed tomography.

    PubMed

    Kanemaru, Kazuya; Kinouchi, Hiroyuki; Yoshioka, Hideyuki; Yagi, Takashi; Wakai, Takuma; Hashimoto, Koji; Fukumoto, Yuichiro; Umeda, Takako; Onishi, Hiroshi; Nishiyama, Yoshihisa; Horikoshi, Toru

    2015-07-01

    The severity of cerebral hemodynamic disturbance caused by retrograde leptomeningeal venous drainage (RLVD) of a dural arteriovenous fistula (dAVF) is related to neurological morbidity and unfavorable outcome. However, the cerebral hemodynamics of this disorder have not been elucidated well. The aim of this study was to assess the relationship between the cerebral venous congestive encephalopathy represented as a high-intensity area (HIA) on T2-weighted MR images and the cerebral hemodynamics examined by (123)I-iodoamphetamine (IMP) single photon emission computed tomography (SPECT), as well as the predictive value of (123)I-IMP SPECT for the development and reversibility of venous congestion encephalopathy. Based on the pre- and posttreatment T2 HIAs associated with venous congestion encephalopathy, patients were divided into 3 groups: a normal group, an edema group, and an infarction group. The regional cerebral blood flow (rCBF) at the region with RLVD was analyzed by (123)I-IMP SPECT, and the results were compared among the groups. There were 11, 6, and 3 patients in the normal, edema, and infarction groups, respectively. No patients in the normal group showed any symptoms related to venous congestion. In contrast, all patients in the edema and infarction groups developed neurological symptoms. The rCBF in the edema group was significantly lower than that in the normal group, and significantly higher than that in the infarction group. The cerebral vascular reactivity (CVR) of the infarction group was significantly lower than that of the normal and edema groups. After treatment, the neurological signs disappeared in the edema group, but only partial improvement was seen in the infarction group. The rCBF also significantly increased in the normal and edema groups, but not in the infarction group. Quantitative rCBF measurement is useful for evaluating hemodynamic disturbance in dAVF with RLVD. The reduction of rCBF was strongly correlated with the severity of

  9. 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.

  10. Markerless motion tracking of awake animals in positron emission tomography.

    PubMed

    Kyme, Andre; Se, Stephen; Meikle, Steven; Angelis, Georgios; Ryder, Will; Popovic, Kata; Yatigammana, Dylan; Fulton, Roger

    2014-11-01

    Noninvasive functional imaging of awake, unrestrained small animals using motion-compensation removes the need for anesthetics and enables an animal's behavioral response to stimuli or administered drugs to be studied concurrently with imaging. While the feasibility of motion-compensated radiotracer imaging of awake rodents using marker-based optical motion tracking has been shown, markerless motion tracking would avoid the risk of marker detachment, streamline the experimental workflow, and potentially provide more accurate pose estimates over a greater range of motion. We have developed a stereoscopic tracking system which relies on native features on the head to estimate motion. Features are detected and matched across multiple camera views to accumulate a database of head landmarks and pose is estimated based on 3D-2D registration of the landmarks to features in each image. Pose estimates of a taxidermal rat head phantom undergoing realistic rat head motion via robot control had a root mean square error of 0.15 and 1.8 mm using markerless and marker-based motion tracking, respectively. Markerless motion tracking also led to an appreciable reduction in motion artifacts in motion-compensated positron emission tomography imaging of a live, unanesthetized rat. The results suggest that further improvements in live subjects are likely if nonrigid features are discriminated robustly and excluded from the pose estimation process.

  11. Brain activity following esophageal acid infusion using positron emission tomography

    PubMed Central

    Kobayashi, Shigeyuki; Abe, Yasuhiko; Tashiro, Manabu; Koike, Tomoyuki; Iijima, Katsunori; Imatani, Akira; Ohara, Shuichi; Watanabe, Satoshi; Fukudo, Shin; Shimosegawa, Tooru

    2010-01-01

    AIM: To investigate symptoms and brain activity following esophageal acid infusion. METHODS: Fifteen healthy volunteers were recruited for the study. Hydrochloric acid (pH 1 and 2) and distilled water (pH 7) were randomly and repeatedly infused into the esophagus. The brain activity was evaluated by positron emission tomography. The severity of heartburn elicited by the infusion was rated on an auditory analog scale of 0-10. RESULTS: The severity of heartburn following each infusion showed a step-wise increase with increasing acidity of the perfusate. The heartburn scores were significantly higher in the second pH 1 infusion compared with the first infusion. Acid and distilled water infusion induced activation of various brain areas such as the anterior insula, temporal gyrus, and anterior/posterior cingulate cortex. At pH 1 or 2, in particular, activation was observed in some emotion-related brain areas such as the more anterior part of the anterior cingulate cortex, parahippocampal gyrus, or the temporal pole. Strong activation of the orbitofrontal cortex was found by subtraction analysis of the two second pH 1 infusions, with a significant increase of heartburn symptoms. CONCLUSION: Emotion-related brain areas were activated by esophageal acid stimulation. The orbitofrontal area might be involved in symptom processing, with esophageal sensitization induced by repeated acid stimulation. PMID:21086568

  12. [Methods and clinical applications of positron emission tomography in endocrinology].

    PubMed

    De Landsheere, C; Lamotte, D

    1990-01-01

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

  13. The economics of creating a positron emission tomography center.

    PubMed

    Lissak, R J

    2000-10-01

    Positron emission tomography (PET) scanning has been a powerful research tool since its inception. Changes in the marketplace that have allowed PET to move into the clinical environment include the commercial availability of appropriate radiopharmaceuticals, reimbursement of procedures by insurance companies, and increasing awareness of physicians of the benefits of PET. Facilities that are interested in clinical PET need to develop a process to purchase equipment with an appropriate business plan. This is necessary to assure financial viability and to convince hospital administrators of the viability. The creation of a successful PET program requires an understanding of all aspects relating to a center. The process begins with reviewing the mission statement of the facility. The next step is to prepare the feasibility study, which includes reviewing the existing marketplace and determining the volume, level of referring physicians' interest, and availability of radiopharmaceuticals. Finally, an appropriate pro forma needs to be constructed to facilitate the final decision concerning the potential financial viability of such an endeavor.

  14. Variation in Positron Emission Tomography Use After Colon Cancer Resection

    PubMed Central

    Bailey, Christina E.; Hu, Chung-Yuan; You, Y. Nancy; Kaur, Harmeet; Ernst, Randy D.; Chang, George J.

    2015-01-01

    Purpose: Colon cancer surveillance guidelines do not routinely include positron emission tomography (PET) imaging; however, its use after surgical resection has been increasing. We evaluated the secular patterns of PET use after surgical resection of colon cancer among elderly patients and identified factors associated with its increasing use. Patients and Methods: We used the SEER-linked Medicare database (July 2001 through December 2009) to establish a retrospective cohort of patients age ≥ 66 years who had undergone surgical resection for colon cancer. Postoperative PET use was assessed with the test for trends. Patient, tumor, and treatment characteristics were analyzed using univariable and multivariable logistic regression analyses. Results: Of the 39,221 patients with colon cancer, 6,326 (16.1%) had undergone a PET scan within 2 years after surgery. The use rate steadily increased over time. The majority of PET scans had been performed within 2 months after surgery. Among patients who had undergone a PET scan, 3,644 (57.6%) had also undergone preoperative imaging, and 1,977 (54.3%) of these patients had undergone reimaging with PET within 2 months after surgery. Marriage, year of diagnosis, tumor stage, preoperative imaging, postoperative visit to a medical oncologist, and adjuvant chemotherapy were significantly associated with increased PET use. Conclusion: PET use after colon cancer resection is steadily increasing, and further study is needed to understand the clinical value and effectiveness of PET scans and the reasons for this departure from guideline-concordant care. PMID:25852143

  15. 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.

  16. 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

  17. Sooting flame thermometry using emission/absorption tomography

    NASA Astrophysics Data System (ADS)

    Hall, Robert J.; Bonczyk, Paul A.

    1990-11-01

    A sooting flame temperature measurement technique has been demonstrated based on emission-absorption tomography. The approach applies the algorithms of Fourier transform tomography to deconvolve local soot absorption coefficient and Planck function (temperature) from sets of parallel line-of-sight measurements. The technique has the advantage that it is experimentally simple and does not require involved data reduction. For small particles, there is also no sensitivity of the inferred temperature to possibly uncertain medium parameters. Its main limitation seems to be that it will not work for vanishingly small absorption, but this could be overcome in practice by seeding and then performing all work at the wavelength of a seed resonance. While in principle limited to optically thin flames, accurate corrections for moderate optical thickness can often be made. A self-consistent comparison of measured global radiation from a sooting ethylene flame with a radiative transfer calculation based on measured temperature and soot absorption parameters has been performed.

  18. Sooting flame thermometry using emission/absorption tomography.

    PubMed

    Hall, R J; Bonczyk, P A

    1990-11-01

    A sooting flame temperature measurement technique has been demonstrated based on emission-absorption tomography. The approach applies the algorithms of Fourier transform tomography to deconvolve local soot absorption coefficient and Planck function (temperature) from sets of parallel line-of-sight measurements. The technique has the advantage that it is experimentally simple and does not require involved data reduction. For small particles, there is also no sensitivity of the inferred temperature to possibly uncertain medium parameters. Its main limitation seems to be that it will not work well for vanishingly small absorption, but this could be overcome in practice by seeding and then performing all work at the wavelength of a seed resonance. While in principle limited to optically thin flames, accurate corrections for moderate optical thickness can often be made. A self-consistent comparison of measured global radiation from a sooting ethylene flame with a radiative transfer calculation based on measured temperature and soot absorption parameters has been performed.

  19. History and future technical innovation in positron emission tomography.

    PubMed

    Jones, Terry; Townsend, David

    2017-01-01

    Instrumentation for positron emission tomography (PET) imaging has experienced tremendous improvements in performance over the past 60 years since it was first conceived as a medical imaging modality. Spatial resolution has improved by a factor of 10 and sensitivity by a factor of 40 from the early designs in the 1970s to the high-performance scanners of today. Multimodality configurations have emerged that combine PET with computed tomography (CT) and, more recently, with MR. Whole-body scans for clinical purposes can now be acquired in under 10 min on a state-of-the-art PET/CT. This paper will review the history of these technical developments over 40 years and summarize the important clinical research and healthcare applications that have been made possible by these technical advances. Some perspectives for the future of this technology will also be presented that promise to bring about new applications of this imaging modality in clinical research and healthcare.

  20. 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

  1. [Positron emission tomography and computed tomography (PET/CT) in lung cancer].

    PubMed

    Altamirano-Ley, Javier; Estrada-Sánchez, Gisela Rocío; Ochoa-Carrillo, Francisco Javier

    2007-01-01

    Lung cancer is the most frequent cause of death due to neoplasm in Western populations, with >660,000 new diagnoses of lung cancer per year according to the World Health Organization. We undertook this study to emphasize the role of positron emission tomography to all health care professionals involved in lung cancer diagnosis. There are false negatives with PET-(18)FDG in carcinoids and broncheoalveolar carcinoma in almost 40% of the cases. One relatively common cause of false positives is the vocal cord and adjacent muscles contralateral and compensatory to the lung lesion that show an increased uptake of (18)FDG because of lesions in the laryngeal nerve by the tumor or secondary to surgery. It should not be confounded with metastases. There is sufficient scientific evidence pointing to the usefulness of PET studies and its evolution to PET/CT, especially in patients with lung cancer. This can resolve doubts by the oncologist and patient when there is a suspicious malignant lesion by the following: characterizing solitary pulmonary nodules (benign or malignant), localizing the optimal site for the biopsy, diagnosis of the primary tumor for initial staging, evaluation of mediastinal involvement and distant metastasis, evaluate and restage residual tumor, assessment of recurrence, monitoring response, prognostic prediction and radiotherapy planning.

  2. 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.

  3. Does positron emission tomography/computed tomography aid the diagnosis of prosthetic valve infective endocarditis?

    PubMed

    Balmforth, Damian; Chacko, Jacob; Uppal, Rakesh

    2016-10-01

    A best evidence topic was constructed according to a structured protocol. The question addressed was whether (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) aids the diagnosis of prosthetic valve endocarditis (PVE)? A total of 107 publications were found using the reported search, of which 6 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The reported outcome of all studies was a final diagnosis of confirmed endocarditis on follow-up. All the six studies were non-randomized, single-centre, observational studies and thus represented level 3 evidence. The diagnostic capability of PET/CT for PVE was compared with that of the modified Duke Criteria and echocardiography, and reported in terms of sensitivity, specificity and positive and negative predictive values. All studies demonstrated an increased sensitivity for the diagnosis of PVE when PET/CT was combined with the modified Duke Criteria on admission. A higher SUVmax on PET was found to be significantly associated with a confirmed diagnosis of endocarditis and an additional diagnostic benefit of PET/CT angiography over conventional PET/non-enhanced CT is reported due to improved anatomical resolution. However, PET/CT was found to be unreliable in the early postoperative period due to its inability to distinguish between infection and residual postoperative inflammatory changes. PET/CT was also found to be poor at diagnosing cases of native valve endocarditis. We conclude that PET/CT aids in the diagnosis of PVE when combined with the modified Duke Criteria on admission by increasing the diagnostic sensitivity. The diagnostic ability of PET/CT can be potentiated by the use of PET/CTA; however, its use may be unreliable in the early postoperative period or in native valve endocarditis. © The Author 2016. Published by

  4. The Alzheimer's Disease Neuroimaging Initiative positron emission tomography core.

    PubMed

    Jagust, William J; Bandy, Dan; Chen, Kewei; Foster, Norman L; Landau, Susan M; Mathis, Chester A; Price, Julie C; Reiman, Eric M; Skovronsky, Daniel; Koeppe, Robert A

    2010-05-01

    This is a progress report of the Alzheimer's Disease Neuroimaging Initiative (ADNI) positron emission tomography (PET) Core. The Core has supervised the acquisition, quality control, and analysis of longitudinal [(18)F]fluorodeoxyglucose PET (FDG-PET) data in approximately half of the ADNI cohort. In an "add on" study, approximately 100 subjects also underwent scanning with [(11)C] Pittsburgh compound B PET for amyloid imaging. The Core developed quality control procedures and standardized image acquisition by developing an imaging protocol that has been widely adopted in academic and pharmaceutical industry studies. Data processing provides users with scans that have identical orientation and resolution characteristics despite acquisition on multiple scanner models. The Core labs have used many different approaches to characterize differences between subject groups (Alzheimer's disease, mild cognitive impairment, controls), to examine longitudinal change over time in glucose metabolism and amyloid deposition, and to assess the use of FDG-PET as a potential outcome measure in clinical trials. ADNI data indicate that FDG-PET increases statistical power over traditional cognitive measures, might aid subject selection, and could substantially reduce the sample size in a clinical trial. Pittsburgh compound B PET data showed expected group differences, and identified subjects with significant annual increases in amyloid load across the subject groups. The next activities of the PET core in ADNI will entail developing standardized protocols for amyloid imaging using the [(18)F]-labeled amyloid imaging agent AV45, which can be delivered to virtually all ADNI sites. ADNI has demonstrated the feasibility and utility of multicenter PET studies and is helping to clarify the role of biomarkers in the study of aging and dementia. Copyright 2010 The Alzheimer

  5. Positron Emission Tomography (PET) for benign and malignant disease

    PubMed Central

    Visioni, Anthony; Kim, Julian

    2011-01-01

    Synopsis Functional imaging using radiolabeled probes which specifically bind and accumulate in target tissues has improved the sensitivity and specificity of conventional imaging. Positron Emission Tomography using modified glucose probes (FDG-PET) has demonstrated improved diagnostic accuracy in differentiating benign from malignant lesions in the setting of solitary pulmonary nodules. In addition, FDG-PET has become a useful modality in pre-operative staging of patients with lung cancer and is being tested with many other malignancies for its ability to change patient management. This article provides an overview of the current status of FDG-PET and presents the challenges of moving towards routine use. PMID:21184913

  6. [Positron emission tomography: diagnostic imaging on a molecular level].

    PubMed

    Allemann, K; Wyss, M; Wergin, M; Bley, C Rohrer; Ametamay, S; Bruehlmeier, M; Kaser-Hotz, B

    2004-08-01

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

  7. 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.

  8. [Positron emission tomography and scintigraphy. Nuclear imaging in clinical orthopaedics].

    PubMed

    Kirsch, C M

    2006-09-01

    Nuclear medicine uses the function of organs or organ systems to diagnose and treat disease. The source of radiation is brought into the patient's body by means of a radioactive labelled pharmaceutical. Its way through the body is recorded by appropriate equipment on the outside. Of the many nuclear medical procedures, those primarily applicable to orthopaedic problems are explained here, such as bone scintigraphy, scintigraphy of inflammatory lesions, and tumour scintigraphy. Besides their use in diagnostics, therapeutic applications are covered as well. Using examples from clinical practice, "conventional" nuclear medicine and positron emission tomography are also covered.

  9. 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.

  10. Positron emission tomography: the conceptual idea using a multidisciplinary approach.

    PubMed

    Paans, Anne M J; van Waarde, Aren; Elsinga, Philip H; Willemsen, Antoon T M; Vaalburg, Willem

    2002-07-01

    Positron emission tomography (PET) is a method for quantitatively measuring biochemical and physiological processes in vivo by using radiopharmaceuticals labeled with positron-emitting radionuclides such as 11C, 13N, 15O, and 18F and by measuring the annihilation radiation using a coincidence technique. This technique is also used for measurement of the pharmacokinetics of labeled drugs and measurement of the effects of drugs on metabolism. Deviations from normal metabolism can be measured and insight into biological processes responsible for diseases can be obtained.

  11. Silicon as an Unconventional Detector in Positron Emission Tomography

    PubMed Central

    Clinthorne, N.H.; Brzezinski, K.; Chesi, E.; Cochran, E.; Grkovski, M.; Grošičar, B.; Honscheid, K.; Huh, S.; Kagan, H.; Lacasta, C.; Linhart, V.; Mikuž, M.; Smith, S.; Stankova, V.; Studen, A.; Weilhammer, P.; žontar, D.

    2012-01-01

    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 a successful in achieving ~5mm FWHM spatial resolution in human studies and ~1mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches. Foremost is its high spatial resolution in 3D: our past studies show that there is little diffculty in localizing 511 keV photon interactions to ~0.3mm. Since spatial resolution and reconstructed image noise trade off in a highly non-linear manner that depends on the PET instrument response, if high spatial resolution is the goal, silicon may outperform standard PET detectors even though it has lower sensitivity to 511 keV photons. To evaluate silicon in a variety of PET “magnifying glass” configurations, an instrument has been constructed that consists of an outer partial-ring of PET scintillation detectors into which various arrangements of silicon detectors can be inserted to emulate dual-ring or imaging probe geometries. Recent results have demonstrated 0.7 mm FWHM resolution using pad detectors having 16×32 arrays of 1.4mm square pads and setups have shown promising results in both small animal and PET imaging probe configurations. Although many challenges remain, silicon has potential to become the PET detector of choice when spatial resolution is the primary consideration. PMID:23230345

  12. 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. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. 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.

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

    PubMed Central

    Vaquero, Juan José; Kinahan, Paul

    2017-01-01

    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. 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.

  16. Fasciola Hepatica Mimicking Malignancy on 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Sürücü, Erdem; Demir, Yusuf; Dülger, Ahmet C.; Batur, Abdüssamed; Ölmez, Şehmus; Kitapçı, Mehmet T.

    2016-01-01

    A 48-year-old female with complaints of gastrointestinal symptoms such as abdominal pain, fatigue, vomiting, nausea, and weight loss was diagnosed with neuroendocrine tumor after removal of a 2 mm lesion from the stomach with endoscopic biopsy. Her magnetic resonance imaging that was performed due to on-going symptoms showed multiple linear hypointense lesions in the liver. Positron emission tomography/computed tomography (PET/CT) scan was performed for differential diagnosis, which showed high fluorodeoxyglucose (FDG) uptake in these lesions. Clinical and laboratory findings revealed the final diagnosis as Fasciola hepatica. The imaging features of this case is presented to aid in differentiating this infectious disease from malignancy and avoid misdiagnosis on FDG-PET/CT. PMID:27751978

  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. Positron Emission Tomography Computed Tomography: A Guide for the General Radiologist.

    PubMed

    Beadsmoore, Clare; Newman, David; MacIver, Duncan; Pawaroo, Davina

    2015-11-01

    Cancer remains a leading cause of death in Canada and worldwide. Whilst advances in anatomical imaging to detect and monitor malignant disease have continued over the last few decades, limitations remain. Functional imaging, such as positron emission tomography (PET), has improved the sensitivity and specificity in detecting malignant disease. In combination with computed tomography (CT), PET is now commonly used in the oncology setting and is an integral part of many cancer patients' pathways. Although initially the CT component of the study was purely for attenuation of the PET imaging and to provide anatomical coregistration, many centers now combine the PET study with a diagnostic quality contrast enhanced CT to provide one stop staging, thus refining the patient's pathway. The commonest tracer used in everyday practice is FDG (F18-fluorodeoxyglucose). There are many more tracers in routine clinical practice and those with emerging roles, such as 11C-choline, useful in the imaging of prostate cancer; 11C-methionine, useful in imaging brain tumours; C11-acetate, used in imaging hepatocellular carcinomas; 18F-FLT, which can be used as a marker of cellular proliferation in various malignancies; and F18-DOPA and various 68Ga-somatostatin analogues, used in patients with neuroendocrine tumours. In this article we concentrate on FDG PETCT as this is the most commonly available and widely utilised tracer now used to routinely stage a number of cancers. PETCT alters the stage in approximately one-third of patients compared to anatomical imaging alone. Increasingly, PETCT is being used to assess early metabolic response to treatment. Metabolic response can be seen much earlier than a change in the size/volume of the disease which is measured by standard CT imaging. This can aid treatment decisions in both in terms of modifying therapy and in addition to providing important prognostic information. Furthermore, it is helpful in patients with distorted anatomy from surgery

  19. Long-term outcome of (18) F-fluorodeoxyglucose-positron emission tomography-guided dose painting for head and neck cancer: Matched case-control study.

    PubMed

    Berwouts, Dieter; Madani, Indira; Duprez, Frédéric; Olteanu, AnaMaria Luiza; Vercauteren, Tom; Boterberg, Tom; Deron, Philippe; Bonte, Katrien; Huvenne, Wouter; De Neve, Wilfried; Goethals, Ingeborg

    2017-08-21

    The purpose of this study was to report the long-term outcome of (18) F-fluorodeoxyglucose-positron emission tomography ((18) F-FDG-PET)-guided dose painting for head and neck cancer in comparison to conventional intensity-modulated radiotherapy (IMRT) in a matched case-control study. Seventy-two patients with nonmetastatic head and neck cancer treated with dose painting were compared with 72 control patients matched on tumor site and T classification. Either (18) F-FDG-PET-guided dose painting by contour (DPBC) or voxel intensity-based dose painting by number (DPBN) was performed; control patients underwent standard IMRT. A total median dose to the dose-painted target was 70.2-85.9 Gy/30-32 fractions versus 69.1 Gy/32 fractions with conventional IMRT. In 31 patients, dose painting was adapted to per-treatment changes in the tumor and organs-at-risk (OAR). Median follow-up in living dose-painting and control patients was 87.7 months (range 56.1-119.3) and 64.8 months (range 46.3-83.4), respectively. Five-year local control rates in the dose-painting patients were 82.3% against 73.6% in the control (P = .36); in patients treated to normalized isoeffective doses >91 Gy (NID2Gy) local control reached 85.7% at 5 years against 73.6% in the control group (P =.39). There was no difference in regional (P = .82) and distant control (P = .78). Five-year overall and disease-specific survival rates were 36.3% versus 38.1% (P = .50) and 56.5% versus 51.7% (P = .72), respectively. A half of the dose-painting patients developed acute grade ≥3 dysphagia (P = .004). Late grade 4 mucosal ulcers at the site of dose escalation in 9 of 72 patients was the most common severe toxicity with dose painting versus 3 of 72 patients with conventional IMRT (P = .11). Patients in the dose-painting group had increased rates of acute and late dysphagia (P = .004 and P = .005). Dose-painting strategies can be used to increase dose to specific tumor subvolumes. Five-year local, regional, and

  20. Pure hemidystonia with basal ganglion abnormalities on positron emission tomography

    SciTech Connect

    Perlmutter, J.S.; Raichle, M.E.

    1984-03-01

    We present a patient with hemidystonia and an abnormality of the contralateral basal ganglion seen only with positron emission tomography. A 50-year-old sinistral man suffered minor trauma to the right side of his head and neck. Within 20 minutes he developed paroxysmal intermittent dystonic posturing of his right face, forearm, hand, and foot, with weaker contractions of the left foot, lasting several seconds and recurring every few minutes. Neurological findings between spells were normal. The following were also normal: electrolyte, calcium, magnesium, and arterial blood gas levels, and findings of drug screen, cerebrospinal fluid examination, electroencephalography with nasopharyngeal leads, computed tomographic scanning (initially and four weeks later), and cerebral angiography. Positron emission tomographic scanning revealed abnormalities in the left basal ganglion region, including decreased oxygen metabolism, decreased oxygen extraction, increased blood volume, and increased blood flow.

  1. 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

  2. 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.

  3. Positron emission tomography (PET) and macromolecular delivery in vivo.

    PubMed

    Strauss, Ludwig G; Dimitrakopoulou-Strauss, Antonia

    2009-01-01

    Positron emission tomography (PET) examinations with F-18-fluorodeoxyglucose (FDG) provide detailed information about the glucose-like metabolism in tissue. It is generally accepted that FDG reflects the viability of tumour cells. The kinetics of FDG is modulated by several genes, besides the glucose transporters and hexokinases. Additional specific information can be obtained non-invasively by using other tracers specific for cell membrane receptors. PET studies with radiolabelled peptides have emerged as a new diagnostic tool for imaging of certain tumour entities, like neuroendocrine tumours (NETs) and gastrointestinal stromal tumours (GISTs). This application is based on certain properties of these tumours, like the overexpression of somatostatin receptors, which can be visualised by somatostatin analogues, like 1,4,7,10-tetraazacyclododecane-N, N', N'', N'''-tetraacetic-acid-D: -Phe1-Tyr3 octreotide (DOTATOC) in NET. The overexpression of gastrin-releasing peptide (GRP) receptors can be visualised in GIST by using bombesin analogues. These peptides can be labelled by (68)Ga, which is a generator product and therefore more cost-effective than cyclotron products. (68)Ga-DOTATOC is a peptide that binds primarily to somatostatin receptor subtype 2 (SSTR2). PET studies with (68)Ga-DOTATOC are performed in patients with NET and some other tumours. (68)Ga-BZH3 ((68)Ga-Bombesin) is a peptide that binds to at least three bombesin receptor subtypes: the BB1 (also known as neuromedin B), the BB2 (also known as GRP), and the BB3 (bombesin receptor subtype 3). This bombesin analogue, (68)Ga-BZH3, is used in patients with GIST.

  4. Nonhuman primate positron emission tomography neuroimaging in drug abuse research.

    PubMed

    Howell, Leonard Lee; Murnane, Kevin Sean

    2011-05-01

    Positron emission tomography (PET) neuroimaging in nonhuman primates has led to significant advances in our current understanding of the neurobiology and treatment of stimulant addiction in humans. PET neuroimaging has defined the in vivo biodistribution and pharmacokinetics of abused drugs and related these findings to the time course of behavioral effects associated with their addictive properties. With novel radiotracers and enhanced resolution, PET neuroimaging techniques have also characterized in vivo drug interactions with specific protein targets in the brain, including neurotransmitter receptors and transporters. In vivo determinations of cerebral blood flow and metabolism have localized brain circuits implicated in the effects of abused drugs and drug-associated stimuli. Moreover, determinations of the predisposing factors to chronic drug use and long-term neurobiological consequences of chronic drug use, such as potential neurotoxicity, have led to novel insights regarding the pathology and treatment of drug addiction. However, similar approaches clearly need to be extended to drug classes other than stimulants. Although dopaminergic systems have been extensively studied, other neurotransmitter systems known to play a critical role in the pharmacological effects of abused drugs have been largely ignored in nonhuman primate PET neuroimaging. Finally, the study of brain activation with PET neuroimaging has been replaced in humans mostly by functional magnetic resonance imaging (fMRI). There has been some success in implementing pharmacological fMRI in awake nonhuman primates. Nevertheless, the unique versatility of PET imaging will continue to complement the systems-level strengths of fMRI, especially in the context of nonhuman primate drug abuse research.

  5. 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging in a Patient with HIV (-) Kaposi Sarcoma

    PubMed Central

    Cengiz, Arzu; Şavk, Ekin; Tataroğlu, Canten; Yürekli, Yakup

    2016-01-01

    Kaposi sarcoma (KS) is a vascular neoplasm that often manifests with multiple vascular nodules on the skin and other organs. Various imaging modalities can be used to display disease extent. Herein we present a 65-year-old female patient with human immunodeficiency virus negative KS along with her whole-body positron emission tomography/computed tomography imaging findings. PMID:27751977

  6. Rare case of an ovarian vein tumor thrombosis identified on fluorodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Chandra, Piyush; Agrawal, Archi; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    Fludeoxyglucose positron emission tomography/computed tomography is valuable in the identification of tumor thrombus and differentiating it from bland thrombus which has implications in initiating anticoagulation. We present a rare case of tumor thrombosis in ovarian vein, in a recurrent case of uterine carcinosarcoma. PMID:27833321

  7. Sensory experience of food and obesity: a positron emission tomography study of the brain regions affected by tasting a liquid meal after a prolonged fast.

    PubMed

    DelParigi, Angelo; Chen, Kewei; Salbe, Arline D; Reiman, Eric M; Tataranni, P Antonio

    2005-01-15

    The sensory experience of food is a primary reinforcer of eating and overeating plays a major role in the development of human obesity. However, whether the sensory experience of a forthcoming meal and the associated physiological phenomena (cephalic phase response, expectation of reward), which prepare the organism for the ingestion of food play a role in the regulation of energy intake and contribute to the development of obesity remains largely unresolved. We used positron emission tomography (PET) and 15O-water to measure changes in regional cerebral blood flow (rCBF) and to assess the brain's response to the oral administration of 2 ml of a liquid meal (Ensure Plus, 1.5 kcal/ml) after a 36-h fast and shortly before consuming the same meal. Twenty-one obese (BMI > 35 kg/m2, 10M/11F, age 28 +/- 6 years, body fat 40 +/- 6%) and 20 lean individuals (BMI < 25 kg/m2, 10M/10F, age 33 +/- 9 years, body fat 21 +/- 7%) were studied. Compared to lean individuals, obese individuals had higher fasting plasma glucose (83.3 +/- 6.2 vs. 75.5 +/- 9.6 mg/dl; P = 0.0003) and insulin concentrations (6.1 +/- 3.5 vs. 2.5 +/- 1.7 microU/ml; P < 0.0001) and were characterized by a higher score of dietary disinhibition (i.e., the susceptibility of eating behavior to emotional factors and sensory cues, 5.7 +/- 3.6 vs. 3.5 +/- 2.7; P = 0.01) assessed by the Three Factor Eating Questionnaire. In response to the sensory experience of food, differences in rCBF were observed in several regions of the brain, including greater increases in the middle-dorsal insula and midbrain, and greater decreases in the posterior cingulate, temporal, and orbitofrontal cortices in obese compared to lean individuals (P < 0.05, after small volume correction). In a multiple regression model, percentage of body fat (P = 0.04), glycemia (P = 0.01), and disinhibition (P = 0.07) were independent correlates of the neural response to the sensory experience of the meal in the middle-dorsal insular cortex (R2 = 0

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

    PubMed

    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 (18)F-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 (18)F-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.

  9. 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

  10. Intracranial Leptomeningeal Carcinomatosis in Three Cases from Breast Cancer Demonstrated on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography.

    PubMed

    Ortapamuk, Hulya; Demir, Mustafa Kemal

    2017-01-01

    Leptomeningeal carcinomatosis (LC) is an uncommon late manifestation of non-central nervous system (CNS) solid tumors. With prolonged survival in solid tumors, an increased frequency of metastases is noted in these tumors too. The detection of tumor cells in the cerebrospinal fluid remains the gold standard. Noninvasively, magnetic resonance imaging is frequently used for the diagnosis of LC. Although its low sensitivity of F-18 fluorodeoxyglucose positron emission tomography/computerized tomography (F-18 FDG PET/CT) on demonstrating CNS lesions, it could be useful in identifying the possibility of LC of breast carcinoma by giving high attention to the meninges. We discuss here three cases all of them having intracranial LC; where (18)F-FDG PET/CT study helped us in the diagnosis of LC. To our knowledge, this is the second report about intracranial LC from breast cancer demonstrating on (18)F-FDG PET/CT.

  11. Intracranial Leptomeningeal Carcinomatosis in Three Cases from Breast Cancer Demonstrated on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography

    PubMed Central

    Ortapamuk, Hulya; Demir, Mustafa Kemal

    2017-01-01

    Leptomeningeal carcinomatosis (LC) is an uncommon late manifestation of non-central nervous system (CNS) solid tumors. With prolonged survival in solid tumors, an increased frequency of metastases is noted in these tumors too. The detection of tumor cells in the cerebrospinal fluid remains the gold standard. Noninvasively, magnetic resonance imaging is frequently used for the diagnosis of LC. Although its low sensitivity of F-18 fluorodeoxyglucose positron emission tomography/computerized tomography (F-18 FDG PET/CT) on demonstrating CNS lesions, it could be useful in identifying the possibility of LC of breast carcinoma by giving high attention to the meninges. We discuss here three cases all of them having intracranial LC; where 18F-FDG PET/CT study helped us in the diagnosis of LC. To our knowledge, this is the second report about intracranial LC from breast cancer demonstrating on 18F-FDG PET/CT. PMID:28242978

  12. ACR-SPR-STR Practice Parameter for the Performance of Cardiac Positron Emission Tomography - Computed Tomography (PET/CT) Imaging.

    PubMed

    Subramaniam, Rathan M; Janowitz, Warren R; Johnson, Geoffrey B; Lodge, Martin A; Parisi, Marguerite T; Ferguson, Mark R; Hellinger, Jeffrey C; Gladish, Gregory W; Gupta, Narainder K

    2017-09-15

    This clinical practice parameter has been developed collaboratively by the American College of Radiology (ACR), the Society for Pediatric Radiology (SPR), and the Society of Thoracic Radiology (STR). This document is intended to act as a guide for physicians performing and interpreting positron emission tomography-computed tomography (PET/CT) of cardiac diseases in adults and children. The primary value of cardiac PET/CT imaging include evaluation of perfusion, function, viability, inflammation, anatomy, and risk stratification for cardiac-related events such as myocardial infarction and death. Optimum utility of cardiac PET/CT is achieved when images are interpreted in conjunction with clinical information and laboratory data. Measurement of myocardial blood flow, coronary flow reserve and detection of balanced ischemia are significant advantages of cardiac PET perfusion studies. Increasingly cardiac PET/CT is used in diagnosis and treatment response assessment for cardiac sarcoidosis.

  13. Contrast-enhanced fluorodeoxyglucose positron emission tomography/computed tomography in solid pseudopapillary neoplasm of the pancreas.

    PubMed

    Santhosh, Sampath; Lakshmanan, Ramesh Kumar; Sonik, Bhavay; Padmavathy, Rajagopalan; Gunaseelan, Rajamani Emmanuel

    2016-01-01

    Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare pancreatic tumor with low malignant potential. It occurs characteristically more often in young women. Radiological and pathological studies have revealed that the tumor is quite different from other pancreatic tumors. Limited information is available in the literature reporting their accumulation of fluorine-(18) fluorodeoxyglucose ((18)F-FDG) in positron emission tomography/computed tomography (PET/CT). Here, we report a case of pancreatic SPN imaged with contrast-enhanced FDG PET/CT. A percutaneous fine needle aspiration from the metabolically active lesion revealed SPN, and it was confirmed with histopathological results. Recurrence or metastasis was not found after 7 months of follow-up.

  14. Contrast-enhanced fluorodeoxyglucose positron emission tomography/computed tomography in solid pseudopapillary neoplasm of the pancreas

    PubMed Central

    Santhosh, Sampath; Lakshmanan, Ramesh Kumar; Sonik, Bhavay; Padmavathy, Rajagopalan; Gunaseelan, Rajamani Emmanuel

    2016-01-01

    Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare pancreatic tumor with low malignant potential. It occurs characteristically more often in young women. Radiological and pathological studies have revealed that the tumor is quite different from other pancreatic tumors. Limited information is available in the literature reporting their accumulation of fluorine-18 fluorodeoxyglucose (18F-FDG) in positron emission tomography/computed tomography (PET/CT). Here, we report a case of pancreatic SPN imaged with contrast-enhanced FDG PET/CT. A percutaneous fine needle aspiration from the metabolically active lesion revealed SPN, and it was confirmed with histopathological results. Recurrence or metastasis was not found after 7 months of follow-up. PMID:27095862

  15. [Approach to fever of unknown origin: the role of positron-emission tomography].

    PubMed

    Poncini, Gabriele; Nendaz, Mathieu

    2010-02-03

    Despite important advances in diagnostic medical techniques, feverof unknown origin (FUO) still remains a major challenge. This article tries to determine how much the 18F-fluorodeoxyglucose positron emission tomography coupled to computed tomography (FDG-PET/CT) contributes to the final diagnosis explaining FUO. It also analyzes whether its position in the investigation algorithm may be defined precisely. Our literature review revealed that FDG-PET/CT demonstrates an important potential to replace some traditional radiographic tests but that its position in the strategy of investigations remains to be further defined. The available studies are presently scarce, heterogeneous, and sometimes discordant.

  16. 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.

  17. Bone mineral density and single photon emission computed tomography changes after total knee arthroplasty: a 2-year follow-up study.

    PubMed

    Soininvaara, Tarja; Nikola, Tua; Vanninen, Esko; Miettinen, Hannu; Kröger, Heikki

    2008-03-01

    Dual X-ray absorptionmetry (DXA) provides a highly reproducible method for quantitative analysis and monitoring periprosthetic bone mineral density (BMD) after total knee arthroplasty (TKA). Single photon emission computed tomography (SPECT) with bone avid radiopharmaceuticals reflects bone metabolic activity and circulation. We combined information from DXA and SPECT to assess the evaluation of the dynamic balance between BMD and bone turnover. Sixteen patients underwent serial DXA (Lunar Expert XL) and 99mTc-methylene diphosphonate SPECT measurements until 2 years after TKA. A rapid bone loss, up to 25.5%, was detected in femur during the first six postoperative months. However, tibial periprosthetic BMD remained close to baseline. There was a significant correlation between 12-month SPECT uptake and preceding BMD change in medial tibia (r = 0.5, P = 0.044). At 12 months, SPECT uptakes in the operated knee were notably higher compared with those of the control knee. SPECT uptakes showed statistically significant decreases from 12 months to 24 months, while SPECT uptake in the control knee remained stable. In tibia, the results are more complex; referring that increased bone remodelling is continuing below the tibial tray. Furthermore, femoral diaphyseal uptake remained elevated, while corresponding tibial uptake had levelled off at 2 years. Increased SPECT uptake during the first 2 years after uncomplicated TKA results most likely from normal postoperative bone remodelling. Levelling of SPECT uptake may indicate a new balance between bone loss and regain.

  18. Pharmacokinetics and red cell utilization of iron(III) hydroxide-sucrose complex in anaemic patients: a study using positron emission tomography.

    PubMed

    Beshara, S; Lundqvist, H; Sundin, J; Lubberink, M; Tolmachev, V; Valind, S; Antoni, G; Långström, B; Danielson, B G

    1999-02-01

    The pharmacokinetics of a single intravenous injection of 100 mg iron hydroxide-sucrose complex labelled with a tracer in the form of 52Fe/59Fe was followed in six anaemic patients for a period ranging from 6 to 8 3 h using positron emission tomography (PET). Red cell utilization of the labelled iron was followed for 4 weeks. PET data showed radioactive uptake by the liver, spleen and bone marrow. The uptake by the macrophage-rich spleen demonstrated the reticuloendothelial uptake of this iron preparation, with subsequent effective release of that iron for marrow utilization. Red cell utilization, followed for 4 weeks, ranged from 59% to 97%. The bone marrow influx rate constant was independent of blood iron concentration, indicating non-saturation of the transport system in bone marrow. This implied that higher doses of the iron complex can probably be used in the same setting. A higher influx rate into the marrow compared with the liver seemed to be consistent with higher red cell utilization. This would indicate that early distribution of the injected iron complex may predict the long-term utilization.

  19. A single photon emission computed tomography scan study of striatal dopamine D2 receptor binding with 123I-epidepride in patients with schizophrenia and controls.

    PubMed Central

    Tibbo, P; Silverstone, P H; McEwan, A J; Scott, J; Joshua, A; Golberg, K

    1997-01-01

    The usefulness of 123I-epidepride as a single photon emission computed tomography (SPECT) scan D2 receptor ligand was examined in vivo in 13 medicated patients with schizophrenia and age- and sex-matched normal controls. To establish the effect of endogenous dopamine on 123I-epidepride binding, 4 of the 13 controls also received 20 mg D-amphetamine. The results showed that 123I-epidepride had high specific binding to the striatum in both patients with schizophrenia and normal controls. There was a trend for the total striatal binding of medicated patients with schizophrenia, as measured by total basal ganglia: frontal cortex (TBG:FC) ratios, to be less than the binding of controls (P = 0.053). This trend confirms previous work showing that antipsychotic medication decreases the number of D2 receptors available for binding to the radioligand. Interestingly, there was also a significant relationship between 123I-epidepride binding ratios and global functioning scales (Global Assessment of Functioning scale [GAF]) for schizophrenia (r = 0.56, P = 0.045), although there was no such relationship with the Brief Psychiatric Rating Scale (BPRS). In addition, our results showed that amphetamine-induced dopamine release did not alter 123I-epidepride binding, confirming the high specific binding of 123I-epidepride to the D2 receptor. We conclude that 123I-epidepride appears to be a very useful SPECT ligand for imaging the D2 receptor. PMID:9002391

  20. Initial performance studies of a wearable brain positron emission tomography camera based on autonomous thin-film digital Geiger avalanche photodiode arrays.

    PubMed

    Schmidtlein, Charles R; Turner, James N; Thompson, Michael O; Mandal, Krishna C; Häggström, Ida; Zhang, Jiahan; Humm, John L; Feiglin, David H; Krol, Andrzej

    2017-01-01

    Using analytical and Monte Carlo modeling, we explored performance of a lightweight wearable helmet-shaped brain positron emission tomography (PET), or BET camera, based on thin-film digital Geiger avalanche photodiode arrays with Lutetium-yttrium oxyorthosilicate (LYSO) or [Formula: see text] scintillators for imaging in vivo human brain function of freely moving and acting subjects. We investigated a spherical cap BET and cylindrical brain PET (CYL) geometries with 250-mm diameter. We also considered a clinical whole-body (WB) LYSO PET/CT scanner. The simulated energy resolutions were 10.8% (LYSO) and 3.3% ([Formula: see text]), and the coincidence window was set at 2 ns. The brain was simulated as a water sphere of uniform F-18 activity with a radius of 100 mm. We found that BET achieved [Formula: see text] better noise equivalent count (NEC) performance relative to the CYL and [Formula: see text] than WB. For 10-mm-thick [Formula: see text] equivalent mass systems, LYSO (7-mm thick) had [Formula: see text] higher NEC than [Formula: see text]. We found that [Formula: see text] scintillator crystals achieved [Formula: see text] full-width-half-maximum spatial resolution without parallax errors. Additionally, our simulations showed that LYSO generally outperformed [Formula: see text] for NEC unless the timing resolution for [Formula: see text] was considerably smaller than that presently used for LYSO, i.e., well below 300 ps.

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

    PubMed

    Porenta, G

    1994-01-01

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

  2. Super-resolution in respiratory synchronized positron emission tomography.

    PubMed

    Wallach, Daphné; Lamare, Frédéric; Kontaxakis, Giorgos; Visvikis, Dimitris

    2012-02-01

    Respiratory motion is a major source of reduced quality in positron emission tomography (PET). In order to minimize its effects, the use of respiratory synchronized acquisitions, leading to gated frames, has been suggested. Such frames, however, are of low signal-to-noise ratio (SNR) as they contain reduced statistics. Super-resolution (SR) techniques make use of the motion in a sequence of images in order to improve their quality. They aim at enhancing a low-resolution image belonging to a sequence of images representing different views of the same scene. In this work, a maximum a posteriori (MAP) super-resolution algorithm has been implemented and applied to respiratory gated PET images for motion compensation. An edge preserving Huber regularization term was used to ensure convergence. Motion fields were recovered using a B-spline based elastic registration algorithm. The performance of the SR algorithm was evaluated through the use of both simulated and clinical datasets by assessing image SNR, as well as the contrast, position and extent of the different lesions. Results were compared to summing the registered synchronized frames on both simulated and clinical datasets. The super-resolution image had higher SNR (by a factor of over 4 on average) and lesion contrast (by a factor of 2) than the single respiratory synchronized frame using the same reconstruction matrix size. In comparison to the motion corrected or the motion free images a similar SNR was obtained, while improvements of up to 20% in the recovered lesion size and contrast were measured. Finally, the recovered lesion locations on the SR images were systematically closer to the true simulated lesion positions. These observations concerning the SNR, lesion contrast and size were confirmed on two clinical datasets included in the study. In conclusion, the use of SR techniques applied to respiratory motion synchronized images lead to motion compensation combined with improved image SNR and contrast

  3. Simulation of emission tomography using grid middleware for distributed computing.

    PubMed

    Thomason, M G; Longton, R F; Gregor, J; Smith, G T; Hutson, R K

    2004-09-01

    SimSET is Monte Carlo simulation software for emission tomography. This paper describes a simple but effective scheme for parallel execution of SimSET using NetSolve, a client-server system for distributed computation. NetSolve (version 1.4.1) is "grid middleware" which enables a user (the client) to run specific computations remotely and simultaneously on a grid of networked computers (the servers). Since the servers do not have to be identical machines, computation may take place in a heterogeneous environment. To take advantage of diversity in machines and their workloads, a client-side scheduler was implemented for the Monte Carlo simulation. The scheduler partitions the total decay events by taking into account the inherent compute-speeds and recent average workloads, i.e., the scheduler assigns more decay events to processors expected to give faster service and fewer decay events to those expected to give slower service. When compute-speeds and sustained workloads are taken into account, the speed-up is essentially linear in the number of equivalent "maximum-service" processors. One modification in the SimSET code (version 2.6.2.3) was made to ensure that the total number of decay events specified by the user is maintained in the distributed simulation. No other modifications in the standard SimSET code were made. Each processor runs complete SimSET code for its assignment of decay events, independently of others running simultaneously. Empirical results are reported for simulation of a clinical-quality lung perfusion study.

  4. Ictal onset zone and seizure propagation delineated on ictal F-18 fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Tripathi, Madhavi; Tripathi, Manjari; Garg, Ajay; Damle, Nishikant; Bal, Chandrasekhar

    2016-01-01

    The present case highlights the utility of ictal F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in delineating the seizure onset zone in a child with complex partial seizures. Although F-18 FDG PET has been successfully used to delineate interictal hypometabolism, planned ictal FDG PET, in cases with prolonged seizure activity, can provide better spatial resolution than single-photon emission CT by delineating the seizure onset zone and propagation pathway.

  5. 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.

  6. 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

  7. [Positron emission tomography in neuroscience. An integrative part of clinical diagnostic methods and experimental research].

    PubMed

    Schaller, B

    2005-02-01

    The role of molecular neuroimaging techniques is increasing in the understanding of pathophysiological mechanism of diseases. To date, positron emission tomography is the most powerful tool for the non-invasive study of biochemical and molecular processes in humans and animals in vivo. With the development in radiochemistry and tracer technology, a variety of endogenously expressed and exogenously introduced genes can be analyzed by PET. This opens up the exciting and rapidly field of molecular imaging, aiming at the non-invasive localisation of a biological process of interest in normal and diseased cells in animal models and humans in vivo. Besides its usefulness for basic research positron emission tomography has been proven to be superior to conventional diagnostic methods in several clinical indications. This is illustrated by detection of biological or anatomic changes that cannot be demonstrated by computed tomography or magnetic resonance imaging, as well as even before symptoms are expressed. The present review summarizes the clinical use of positron emission tomography in neuroscience that has helped elucidate the pathophysiology of a number of diseases and has suggested strategies in the treatment of these patients. Special reference is given to the neurovascular, neurodegenerative and neurooncological disease.

  8. Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging in Patients With Carcinoma of the Nasopharynx: Diagnostic Accuracy and Impact on Clinical Management

    SciTech Connect

    Gordin, Arie . E-mail: ariegor@hotmail.com; Golz, Avishay; Daitzchman, Marcello; Keidar, Zohar; Bar-Shalom, Rachel; Kuten, Abraham; Israel, Ora

    2007-06-01

    Purpose: To assess the value of {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma as compared with PET and conventional imaging (CI) alone, and to assess the impact of PET/CT on further clinical management. Methods and Materials: Thirty-three patients with nasopharyngeal carcinoma had 45 PET/CT examinations. The study was a retrospective analysis. Changes in patient care resulting from the PET/CT studies were recorded. Results: Positron emission tomography/computed tomography had sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 92%, 90%, 90%, 90%, and 91%, respectively, as compared with 92%, 65%, 76%, 86%, and 80% for PET and 92%, 15%, 60%, 60%, and 60% for CI. Imaging with PET/CT altered further management of 19 patients (57%). Imaging with PET/CT eliminated the need for previously planned diagnostic procedures in 11 patients, induced a change in the planned therapeutic approach in 5 patients, and guided biopsy to a specific metabolically active area inside an edematous region in 3 patients, thus decreasing the chances for tissue sampling errors and avoiding damage to nonmalignant tissue. Conclusions: In cancer of the nasopharynx, the diagnostic performance of PET/CT is better than that of stand-alone PET or CI. Positron emission tomography/computed tomography had a major impact on further clinical management in 57% of patients.

  9. 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

  10. Right parietal stroke with Gerstmann's syndrome. Appearance on computed tomography, magnetic resonance imaging, and single-photon emission computed tomography.

    PubMed

    Moore, M R; Saver, J L; Johnson, K A; Romero, J A

    1991-04-01

    We examined a patient who exhibited Gerstmann's syndrome (left-right disorientation, finger agnosia, dyscalculia, and dysgraphia) in association with a perioperative stroke in the right parietal lobe. This is the first description of the Gerstmann tetrad occurring in the setting of discrete right hemisphere pathologic findings. A well-localized vascular lesion was demonstrated by computed tomography, magnetic resonance imaging, and single-photon emission computed tomographic studies. The patient had clinical evidence of reversed functional cerebral dominance and radiologic evidence of reversed anatomic cerebral asymmetries.

  11. (18)F-Fluoride and (18)F-Fluorodeoxyglucose Positron Emission Tomography After Transient Ischemic Attack or Minor Ischemic Stroke: Case-Control Study.

    PubMed

    Vesey, Alex T; Jenkins, William S A; Irkle, Agnese; Moss, Alastair; Sng, Greg; Forsythe, Rachael O; Clark, Tim; Roberts, Gemma; Fletcher, Alison; Lucatelli, Christophe; Rudd, James H F; Davenport, Anthony P; Mills, Nicholas L; Al-Shahi Salman, Rustam; Dennis, Martin; Whiteley, William N; van Beek, Edwin J R; Dweck, Marc R; Newby, David E

    2017-03-01

    Combined positron emission tomography (PET) and computed tomography (CT) can assess both anatomy and biology of carotid atherosclerosis. We sought to assess whether (18)F-fluoride or (18)F-fluorodeoxyglucose can identify culprit and high-risk carotid plaque. We performed (18)F-fluoride and (18)F-fluorodeoxyglucose PET/CT in 26 patients after recent transient ischemic attack or minor ischemic stroke: 18 patients with culprit carotid stenosis awaiting carotid endarterectomy and 8 controls without culprit carotid atheroma. We compared standardized uptake values in the clinically adjudicated culprit to the contralateral asymptomatic artery, and assessed the relationship between radiotracer uptake and plaque phenotype or predicted cardiovascular risk (ASSIGN score [Assessing Cardiovascular Risk Using SIGN Guidelines to Assign Preventive Treatment]). We also performed micro PET/CT and histological analysis of excised plaque. On histological and micro PET/CT analysis, (18)F-fluoride selectively highlighted microcalcification. Carotid (18)F-fluoride uptake was increased in clinically adjudicated culprit plaques compared with asymptomatic contralateral plaques (log10standardized uptake valuemean 0.29±0.10 versus 0.23±0.11, P=0.001) and compared with control patients (log10standardized uptake valuemean 0.29±0.10 versus 0.12±0.11, P=0.001). (18)F-Fluoride uptake correlated with high-risk plaque features (remodeling index [r=0.53, P=0.003], plaque burden [r=0.51, P=0.004]), and predicted cardiovascular risk [r=0.65, P=0.002]). Carotid (18)F-fluorodeoxyglucose uptake appeared to be increased in 7 of 16 culprit plaques, but no overall differences in uptake were observed in culprit versus contralateral plaques or control patients. However, (18)F-fluorodeoxyglucose did correlate with predicted cardiovascular risk (r=0.53, P=0.019), but not with plaque phenotype. (18)F-Fluoride PET/CT highlights culprit and phenotypically high-risk carotid plaque. This has the potential to

  12. Mycosis fungoides staged by 18F-flurodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Xu, Lu; Pang, Hua; Zhu, Jin; Chen, Xi; Guan, Lili; Wang, Jie; Chen, Jing; Liu, Ying

    2016-01-01

    Abstract Introduction: Mycosis fungoides is a kind of malignant lymphoma arising from T cells, but primarily occurs in skin, and it is the most common type of cutaneous lymphoma. Mycosis fungoides (MF) is a rare non-Hodgkin lymphoma but the most common type of primary cutaneous T-cell lymphomas. Because of unknown etiology and mechanism, and lack of typical clinical and histophysiological manifestations, the final diagnosis of MF is currently dependent on pathology and immunohistochemistry. Subsequently, tumor staging is very important. Different approaches would be taken according to varying degrees of cutaneous and extracutaneous lesions. Computed tomography (CT) scan has been chosen to stage tumors customarily. However, CT could only provide morphological information and analyze lymphadenopathy by the size criteria. 18F-flurodeoxyglucose positron emission tomography/computed tomography (PET/CT) could provide morphological information and metabolic conditions simultaneously, which is helpful to locate and stage lesion. Conclusion: 18F-flurodeoxyglucose PET/CT could identify cutaneous and extracutaneous lesions in patients with MF. It could provide the range of lesions and biopsy target. PMID:27828842

  13. CO2BOLD assessment of moyamoya syndrome: Validation with single photon emission computed tomography and positron emission tomography imaging

    PubMed Central

    Pellaton, Alain; Bijlenga, Philippe; Bouchez, Laurie; Cuvinciuc, Victor; Barnaure, Isabelle; Garibotto, Valentina; Lövblad, Karl-Olof; Haller, Sven

    2016-01-01

    AIM To compare the assessment of cerebrovascular reserve (CVR) using CO2BOLD magnetic resonance imaging (MRI) vs positron emission tomography (PET) and single photon emission computed tomography (SPECT) as reference standard. METHODS Ten consecutive patients (8 women, mean age of 41 ± 26 years) with moyamoya syndrome underwent 14 pre-surgical evaluations for external-internal carotid artery bypass surgery. CVR was assessed using CO2BOLD and PET (4)/SPECT (11) with a maximum interval of 36 d, and evaluated by two experienced neuroradiologists. RESULTS The inter-rater agreement was 0.81 for SPECT (excellent), 0.43 for PET (fair) and 0.7 for CO2BOLD (good). In 9/14 cases, there was a correspondence between CO2BOLD and PET/SPECT. In 4/14 cases, CVR was over-estimated in CO2BOLD, while in 1/14 case, CVR was underestimated in CO2BOLD. The sensitivity of CO2BOLD was 86% and a specificity of 43%. CONCLUSION CO2BOLD can be used for pre-surgical assessment of CVR in patients with moyamoya syndrome and combines the advantages of absent irradiation, high availability of MRI and assessment of brain parenchyma, cerebral vessels and surrogate CVR in one stop. PMID:27928470

  14. An Assessment of Early Response to Targeted Therapy via Molecular Imaging: A Pilot Study of 3'-deoxy-3'[(18)F]-Fluorothymidine Positron Emission Tomography (18)F-FLT PET/CT in Prostate Adenocarcinoma.

    PubMed

    Kairemo, Kalevi; Ravizzini, Gregory C; Macapinlac, Homer A; Subbiah, Vivek

    2017-04-04

    Fluorothymidine is a thymidine analog labeled with fluorine-18 fluorothymidine for positron emission tomography ((18)F-FLT-PET) imaging. Thymidine is a nucleic acid that is used to build DNA. Fluorine-18 fluorothymidine ((18)F-FLT) utilizes the same metabolic pathway as does thymidine but has a very low incidence of being incorporated into the DNA (<1%). (18)F-FLT-PET could have a role in the evaluation of response to targeted therapy. We present here a pilot study where we investigated cellular metabolism and proliferation in patients with prostate cancer before and after targeted therapy. Seven patients with Stage IV prostate adenocarcinoma, candidates for targeted therapy inhibiting the hepatocyte growth factor/tyrosine-protein kinase Met (HGF/C-MET) pathway, were included in this study. The HGF/C-MET pathway is implicated in prostate cancer progression, and an evaluation of the inhibition of this pathway could be valuable. (18)F-FLT was performed at baseline and within four weeks post-therapy. Tumor response was assessed semi-quantitatively and using visual response criteria. The range of SUVmax for (18)F-FLT at baseline in the prostate varied from 2.5 to 4.2. This study demonstrated that (18)F-FLT with positron emission tomography/computerized tomography ((18)F-FLT PET/CT) had only limited applications in the early response evaluation of prostate cancer. (18)F-FLT PET/CT may have some utility in the assessment of response in lymph node disease. However, (18)F-FLT PET/CT was not found to be useful in the evaluation of the prostate bed, metastatic skeletal disease, and liver disease.

  15. Overview of positron emission tomography chemistry: clinical and technical considerations and combination with computed tomography.

    PubMed

    Koukourakis, G; Maravelis, G; Koukouraki, S; Padelakos, P; Kouloulias, V

    2009-01-01

    The concept of emission and transmission tomography was introduced by David Kuhl and Roy Edwards in the late 1950s. Their work later led to the design and construction of several tomographic instruments at the University of Pennsylvania. Tomographic imaging techniques were further developed by Michel Ter-Pogossian, Michael E. Phelps and others at the Washington University School of Medicine. Positron emission tomography (PET) is a nuclear medicine imaging technique which produces a 3-dimensional image or map of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Images of tracer concentration in 3-dimensional space within the body are then reconstructed by computer analysis. In modern scanners, this reconstruction is often accomplished with the aid of a CT X-ray scan performed on the patient during the same session, in the same machine. If the biologically active molecule chosen for PET is 18F-fluorodeoxyglucose (FDG), an analogue of glucose, the concentrations of tracer imaged give tissue metabolic activity in terms of regional glucose uptake. Although use of this tracer results in the most common type of PET scan, other tracer molecules are used in PET to image the tissue concentration of many other types of molecules of interest. The main role of this article was to analyse the available types of radiopharmaceuticals used in PET-CT along with the principles of its clinical and technical considerations.

  16. Positron emission tomography assessment of large vessel inflammation in patients with newly diagnosed, biopsy-proven giant cell arteritis: a prospective, case-control study.

    PubMed

    Prieto-González, Sergio; Depetris, Marina; García-Martínez, Ana; Espígol-Frigolé, Georgina; Tavera-Bahillo, Itziar; Corbera-Bellata, Marc; Planas-Rigol, Ester; Alba, Marco A; Hernández-Rodríguez, José; Grau, Josep M; Lomeña, Franciso; Cid, Maria C

    2014-07-01

    Positron emission tomography (PET) scan is emerging as a promising imaging technique to detect large-vessel inflammation in giant cell arteritis (GCA). However, the lack of a standardised definition of arteritis based on (18)fluorodeoxyglucose (FDG) uptake is an important limitation to the use of PET scan for diagnostic purposes. To prospectively assess the intensity and distribution of FDG uptake at different vascular territories in patients with newly diagnosed GCA compared with controls. 32 consecutive, biopsy-proven, GCA patients treated with glucocorticoids for ≤3 days were included. The control group consisted of 20 individuals, who underwent PET/CT for cancer staging. Maximal standardised uptake value (SUVm) was calculated at four aortic segments, supraaortic branches and iliac-femoral territory. Sensitivity and specificity was calculated by receiver-operator characteristic curves (ROC) analysis. Mean SUVm was significantly higher in patients than in controls in all vessels explored and correlated with acute-phase reactants and serum IL-6. Mean of the SUVm at all the vascular territories had an area under the curve (AUC) of 0.830, and a cut-off of 1.89 yielded a sensitivity of 80% and a specificity of 79% for GCA diagnosis. There were no significant differences in AUC among the vascular beds examined. FDG uptake by large vessels has a substantial sensitivity and specificity for GCA diagnosis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  17. Quantification of myocardial perfusion using cardiac magnetic resonance imaging correlates significantly to rubidium-82 positron emission tomography in patients with severe coronary artery disease: a preliminary study.

    PubMed

    Qayyum, Abbas A; Hasbak, Philip; Larsson, Henrik B W; Christensen, Thomas E; Ghotbi, Adam A; Mathiasen, Anders B; Vejlstrup, Niels G; Kjaer, Andreas; Kastrup, Jens

    2014-07-01

    Aim was to compare absolute myocardial perfusion using cardiac magnetic resonance imaging (CMRI) based on Tikhonov's procedure of deconvolution and rubidium-82 positron emission tomography (Rb-82 PET). Fourteen patients with coronary artery stenosis underwent rest and adenosine stress imaging by 1.5-Tesla MR Scanner and a mCT/PET 64-slice Scanner. CMRI were analyzed based on Tikhonov's procedure of deconvolution without specifying an explicit compartment model using our own software. PET images were analyzed using standard clinical software. CMRI and PET data was compared with Spearman's rho and Bland-Altman analysis. CMRI results were strongly and significantly correlated with PET results for the absolute global myocardial perfusion differences (r=0.805, p=0.001) and for global myocardial perfusion reserve (MPR) (r=0.886, p<0.001). At vessel territorial level, CMRI results were also significantly correlated with absolute PET myocardial perfusion differences (r=0.737, p<0.001) and MPR (r=0.818, p<0.001). Each vessel territory had similar strong correlation for absolute myocardial perfusion differences (right coronary artery (RCA): r=0.787, p=0.001; left anterior descending artery (LAD): r=0.796, p=0.001; left circumflex artery (LCX): r=0.880, p<0.001) and for MPR (RCA: r=0.895, p<0.001; LAD: r=0.886, p<0.001; LCX: r=0.886, p<0.001). On a global and vessel territorial basis, CMRI-measured absolute myocardial perfusion differences and MPR were strongly and significantly correlated with the Rb-82 PET findings. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Inverse relationship between brain glucose and ketone metabolism in adults during short-term moderate dietary ketosis: A dual tracer quantitative positron emission tomography study.

    PubMed

    Courchesne-Loyer, Alexandre; Croteau, Etienne; Castellano, Christian-Alexandre; St-Pierre, Valérie; Hennebelle, Marie; Cunnane, Stephen C

    2017-07-01

    Ketones (principally β-hydroxybutyrate and acetoacetate (AcAc)) are an important alternative fuel to glucose for the human brain, but their utilisation by the brain remains poorly understood. Our objective was to use positron emission tomography (PET) to assess the impact of diet-induced moderate ketosis on cerebral metabolic rate of acetoacetate (CMRa) and glucose (CMRglc) in healthy adults. Ten participants (35 ± 15 y) received a very high fat ketogenic diet (KD) (4.5:1; lipid:protein plus carbohydrates) for four days. CMRa and CMRglc were quantified by PET before and after the KD with the tracers, (11)C-AcAc and (18)F-fluorodeoxyglucose ((18)F-FDG), respectively. During the KD, plasma ketones increased 8-fold ( p = 0.005) while plasma glucose decreased by 24% ( p = 0.005). CMRa increased 6-fold ( p = 0.005), whereas CMRglc decreased by 20% ( p = 0.014) on the KD. Plasma ketones were positively correlated with CMRa (r = 0.93; p < 0.0001). After four days on the KD, CMRa represented 17% of whole brain energy requirements in healthy adults with a 2-fold difference across brain regions (12-24%). The CMR of ketones (AcAc and β-hydroxybutyrate combined) while on the KD was estimated to represent about 33% of brain energy requirements or approximately double the CMRa. Whether increased ketone availability raises CMR of ketones to the same extent in older people as observed here or in conditions in which chronic brain glucose hypometabolism is present remains to be determined.

  19. In vivo mesolimbic D2/3 receptor binding predicts posttherapeutic clinical responses in restless legs syndrome: a positron emission tomography study.

    PubMed

    Oboshi, Yumi; Ouchi, Yasuomi; Yagi, Shunsuke; Kono, Satoshi; Nakai, Noriyoshi; Yoshikawa, Etsuji; Futatsubashi, Masami; Terada, Tatsuhiro; Kim, Kang; Harada, Kiyoshi

    2012-04-01

    Although D2/3 agonists have been used as a first-line medication for idiopathic restless legs syndrome (iRLS), findings on D2/3 receptors have been inconsistent. Here, we aimed to clarify the contribution of D2/3 receptor function to the clinical symptoms of iRLS by comparing the binding potential (BP(ND)) of [(11)C]raclopride with clinical improvements after D2/3 stimulation by pramipexole. Eight drug-naïve, iRLS patients and eight age-matched healthy subjects were scanned with positron emission tomography (PET). After PET scans, all patients received pramipexole (0.125 mg) orally for 2 weeks. Patients were evaluated every day with several standardized clinical tests. The BP(ND) values were compared using regions of interest and voxel-based methods. Results showed that the mean magnitude of [(11)C]raclopride BP(ND) in the mesolimbic dopamine region (nucleus accumbens (NA) and caudate) was significantly lower in the iRLS group. No significant differences between groups were observed in the putamen. The NA [(11)C]raclopride BP(ND) levels correlated negatively with clinical severity scores and positively with the degree of posttreatment improvement in iRLS. The present results suggest that alterations in mesolimbic D2/3 receptor function reflect the pathophysiology of iRLS, and the baseline availability of D2/3 receptors may predict the clinical outcome after D2/3 agonist treatment.

  20. In-vivo imaging of grey and white matter neuroinflammation in Alzheimer's disease: a positron emission tomography study with a novel radioligand, [18F]-FEPPA.

    PubMed

    Suridjan, I; Pollock, B G; Verhoeff, N P L G; Voineskos, A N; Chow, T; Rusjan, P M; Lobaugh, N J; Houle, S; Mulsant, B H; Mizrahi, R

    2015-12-01

    Our primary aim was to compare neuroinflammation in cognitively intact control subjects and patients with Alzheimer's disease (AD) by using positron emission tomography (PET) with translocator protein 18 kDa (TSPO)-specific radioligand [(18)F]-FEPPA. [(18)F]-FEPPA PET scans were acquired on a high-resolution research tomograph in 21 patients with AD (47- 81 years) and 21 control subjects (49-82 years). They were analyzed by using a 2-tissue compartment model with arterial plasma input function. Differences in neuroinflammation, indexed as [(18)F]-FEPPA binding were compared, adjusting for differences in binding affinity class as determined by a single polymorphism in the TSPO gene (rs6971). In grey matter areas, [(18)F]-FEPPA was significantly higher in AD compared with healthy control subjects. Large increases were seen in the hippocampus, prefrontal, temporal, parietal and occipital cortex (average Cohen's d= 0.89). Voxel-based analyses confirmed significant clusters of neuroinflammation in the frontal, temporal and parietal cortex in patients with AD. In white matter, [(18)F]-FEPPA binding was elevated in the posterior limb of the internal capsule, and the cingulum bundle. Higher neuroinflammation in the parietal cortex (r= -0.7, P= 0.005), and posterior limb of the internal capsule (r= -0.8, P=0.001) was associated with poorer visuospatial function. In addition, a higher [(18)F]-FEPPA binding in the posterior limb of the internal capsule was associated with a greater impairment in language ability (r= -0.7, P=0.004). Elevated neuroinflammation can be detected in AD patients throughout the brain grey and white matter by using [(18)F]-FEPPA PET. Our results also suggest that neuroinflammation is associated with some cognitive deficits.

  1. Gated myocardial perfusion single photon emission computed tomography in the clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial, Veterans Administration Cooperative study no. 424.

    PubMed

    Shaw, Leslee J; Heller, Gary V; Casperson, Paul; Miranda-Peats, Romalisa; Slomka, Piotr; Friedman, John; Hayes, Sean W; Schwartz, Ronald; Weintraub, William S; Maron, David J; Dada, Marcin; King, Spencer; Teo, Koon; Hartigan, Pamela; Boden, William E; O'Rourke, Robert A; Berman, Daniel S

    2006-09-01

    Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial. The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization patients. Substudy 2 (n = 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization in reducing patients' ischemic burdens. The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology. We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based management of patients with stable coronary disease.

  2. Correlation of stable elevations in striatal mu-opioid receptor availability in detoxified alcoholic patients with alcohol craving: a positron emission tomography study using carbon 11-labeled carfentanil.

    PubMed

    Heinz, Andreas; Reimold, Matthias; Wrase, Jana; Hermann, Derik; Croissant, Bernhard; Mundle, Götz; Dohmen, Bernhard M; Braus, Dieter F; Braus, Dieter H; Schumann, Gunter; Machulla, Hans-Jürgen; Bares, Roland; Mann, Karl

    2005-01-01

    The pleasant effects of food and alcohol intake are partially mediated by mu-opiate receptors in the ventral striatum, a central area of the brain reward system. Blockade of mu-opiate receptors with naltrexone reduces the relapse risk among some but not all alcoholic individuals. To test the hypothesis that alcohol craving is pronounced among alcoholic individuals with a high availability of mu-opiate receptors in the brain reward system. Patients and comparison sample. The availability of central mu-opiate receptors was measured in vivo with positron emission tomography (PET) and the radioligand carbon 11-labeled carfentanil in the ventral striatum and compared with the severity of alcohol craving as assessed by the Obsessive Compulsive Drinking Scale (OCDS). Hospitalized care. Volunteer sample of 25 male alcohol-dependent inpatients assessed after detoxification of whom 12 underwent PET again 5 weeks later. Control group of 10 healthy men. After 1 to 3 weeks of abstinence, the availability of mu-opiate receptors in the ventral striatum, including the nucleus accumbens, was significantly elevated in alcoholic patients compared with healthy controls and remained elevated when 12 alcoholic patients had these levels measured 5 weeks later (P<.05 corrected for multiple testing). Higher availability of mu-opiate receptors in this brain area correlated significantly with the intensity of alcohol craving as assessed by the OCDS. Abstinent alcoholic patients displayed an increase in mu-opiate receptors in the ventral striatum, including the nucleus accumbens, which correlated with the severity of alcohol craving. These findings point to a neuronal correlate of alcohol urges.

  3. Relationship between Quantitative Adverse Plaque Features from Coronary CT Angiography and Downstream Impaired Myocardial Flow Reserve by 13N-Ammonia Positron Emission Tomography: A Pilot Study

    PubMed Central

    Dey, Damini; Zamudio, Mariana Diaz; Schuhbaeck, Annika; Orozco, Luis Eduardo Juarez; Otaki, Yuka; Gransar, Heidi; Li, Debiao; Germano, Guido; Achenbach, Stephan; Berman, Daniel S.; Meave, Aloha; Alexanderson, Erick; Slomka, Piotr J.

    2016-01-01

    Background We investigated the relationship of quantitative plaque features from coronary CT Angiography (CTA) and coronary vascular dysfunction by impaired myocardial flow reserve (MFR) by 13N-Ammonia Positron Emission Tomography (PET). Methods and Results Fifty-one patients (32 men, 62.4±9.5 years) underwent combined rest-stress 13N-ammonia PET and CTA scans by hybrid PET/CT. Regional MFR was measured from PET. From CTA, 153 arteries were evaluated by semi-automated software, computing arterial non-calcified plaque (NCP), low-density NCP (NCP<30 HU), calcified and total plaque volumes, and corresponding plaque burden (plaque volumex100%/vessel volume), stenosis, remodeling index, contrast density difference (maximum difference in luminal attenuation per unit area in the lesion), and plaque length. Quantitative stenosis, plaque burden and myocardial mass were combined by boosted ensemble machine-learning algorithm into a composite risk score to predict impaired MFR (MFR≤2.0) by PET, in each artery. Nineteen patients (37%) had impaired regional MFR in at least one territory, (41/153 vessels). Patients with impaired regional MFR had higher arterial NCP (32.4 vs.17.2 %), low-density NCP (7 vs 4 %) and total plaque burden (37 vs 19.3 %, p<0.02). In multivariable analysis with 10-fold cross-validation, NCP burden was the most significant predictor of impaired MFR (Odds Ratio 1.35, p=0.021). For prediction of impaired MFR with 10-fold cross-validation, receiver-operating-characteristics-area-under-the-curve for the composite score was 0.83 (95%CI:0.79–0.91), greater than for quantitative stenosis (0.66, 95%CI:0.57–0.76, p = 0.005). Conclusions Compared to stenosis, arterial NCP burden and a composite score combining quantitative stenosis and plaque burden from CTA significantly improves identification of downstream regional vascular dysfunction. PMID:26467104

  4. 4D seismics in the laboratory: Imaging using acoustic emission tomography

    NASA Astrophysics Data System (ADS)

    Brantut, Nicolas

    2017-04-01

    Over the past three decades, there has been tremendous technological developments of laboratory equipment and studies using acoustic emission and ultrasonic monitoring of rock samples during deformation. Using relatively standard seismological techniques, acoustic emissions can be detected, located in space and time, and source mechanisms can be obtained. In parallel, ultrasonic velocities can be measured routinely using standard pulse-receiver techniques. Despite these major developments, current acoustic emission and ultrasonic monitoring systems are typically used separately, and the poor spatial coverage of acoustic transducers precludes performing active 3D tomography in typical laboratory settings. Here, I present an algorithm and software package that uses both passive acoustic emission data and active ultrasonic measurements to determine acoustic emission locations together with the 3D, anistropic P-wave structure of rock samples during deformation. The technique is analogous to local earthquake tomography, but tailored to the specificities of small scale laboratory tests. The fast marching method is employed to compute the forward problem. The acoustic emission locations and the anisotropic P-wave field are jointly inverted using the Quasi-Newton method. I will present benchmark tests, as well as a real-life example showing the propagation of a compaction front in a porous sandstone.

  5. Transcutaneous measurement of the arterial input function in positron emission tomography

    SciTech Connect

    Litton, J.E.; Eriksson, L. )

    1990-04-01

    Positron emission tomography (PET) provides a powerful tool in medical research. Biochemical function can be both precisely localized and quantitatively measured. To achieve reliable quantitation it is necessary to know the time course of activity concentration in the arterial blood during the measurement. In this study the arterial blood curve from the brachial artery is compared to the activity measured in the internal carotid artery with a new transcutaneous detector.

  6. 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.

  7. Positron emission tomography in patients with clinically diagnosed Alzheimer's disease.

    PubMed Central

    McGeer, P L; Kamo, H; Harrop, R; Li, D K; Tuokko, H; McGeer, E G; Adam, M J; Ammann, W; Beattie, B L; Calne, D B

    1986-01-01

    Fourteen patients who had clinically diagnosed Alzheimer's disease with mild to severe dementia (mean age 69.1 years) were evaluated by calculation of local cerebral metabolic rate for glucose (LCMR-gl) based on uptake of 18F-2-fluoro-2-deoxyglucose (FDG) detected with positron emission tomography (PET). PET scanning showed that the patients had significantly lower LCMR-gl values than 11 age-matched neurologically normal volunteers (mean age 66.3 years). The differences were most marked in the temporal cortex, followed by the frontal, parietal and occipital cortex. In each case the LCMR-gl value was below the lowest control value in at least one cortical area and usually in several; the reduction in LCMR-gl and the number of regions involved in the patients increased with the severity of the dementia. Deficits noted in neuropsychologic testing generally correlated with those predicted from loss of regional cortical metabolism. The patients with Alzheimer's disease were also examined with magnetic resonance imaging, computed tomography or both; the degree of atrophy found showed only a poor correlation with the neuropsychologic deficit. Significant atrophy was also noted in some of the controls. A detailed analysis of LCMR-gl values in selected cerebral regions of various sizes refuted the hypothesis that the reduction in cortical glucose metabolism in Alzheimer's disease is due to the filling by metabolically inert cerebrospinal fluid of space created by tissue atrophy. Images Fig. 2 Fig. 3 Fig. 4 Fig. 7 Fig. 8 Fig. 9 PMID:3512063

  8. 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

  9. Current good manufacturing practice for positron emission tomography drugs.

    PubMed

    2009-12-10

    The Food and Drug Administration (FDA) is issuing regulations on current good manufacturing practice (CGMP) for positron emission tomography (PET) drugs. The regulations are intended to ensure that PET drugs meet the requirements of the Federal Food, Drug, and Cosmetic Act (the act) regarding safety, identity, strength, quality, and purity. In this final rule, we are establishing CGMP regulations for approved PET drugs. For investigational and research PET drugs, the final rule states that the requirement to follow CGMP may be met by complying with these regulations or by producing PET drugs in accordance with the United States Pharmacopeia (USP) general chapter on compounding PET radiopharmaceuticals. We are establishing these CGMP requirements for PET drugs under the provisions of the Food and Drug Administration Modernization Act of 1997 (the Modernization Act). Elsewhere in this issue of the Federal Register, we are announcing the availability of a guidance entitled "PET Drugs--Current Good Manufacturing Practice (CGMP)."

  10. 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.

  11. Positron emission tomography in CNS drug discovery and drug monitoring.

    PubMed

    Piel, Markus; Vernaleken, Ingo; Rösch, Frank

    2014-11-26

    Molecular imaging methods such as positron emission tomography (PET) are increasingly involved in the development of new drugs. Using radioactive tracers as imaging probes, PET allows the determination of the pharmacokinetic and pharmacodynamic properties of a drug candidate, via recording target engagement, the pattern of distribution, and metabolism. Because of the noninvasive nature and quantitative end point obtainable by molecular imaging, it seems inherently suited for the examination of a pharmaceutical's behavior in the brain. Molecular imaging, most especially PET, can therefore be a valuable tool in CNS drug research. In this Perspective, we present the basic principles of PET, the importance of appropriate tracer selection, the impact of improved radiopharmaceutical chemistry in radiotracer development, and the different roles that PET can fulfill in CNS drug research.

  12. (68)Ga-labeled radiopharmaceuticals for positron emission tomography.

    PubMed

    Shetty, Dinesh; Lee, Yun-Sang; Jeong, Jae Min

    2010-12-01

    (68)Ga is a promising emerging radionuclide for positron emission tomography (PET). It is produced using a (68)Ge/(68)Ga-generator, and thus, would enable the cyclotron-independent distribution of PET. However, new (68)Ga-labeled radiopharmaceuticals that can replace (18)F-labeled agents like [(18)F]fluorodeoxyglucose (FDG) are needed. Most of the (68)Ga-labeled derivatives currently used are peptide agents, but the developments of other agents, such as amino acid derivatives, nitroimidazole derivatives, and glycosylated human serum albumin, are being actively pursued in many laboratories. Thus, appearance of new (68)Ga-labeled radiopharmaceuticals with high impact are expected in the near future. Here, we present an overview of (68)Ga-labeled agents in terms of their clinical significances and relevances to the management of certain tumors, and pertinent pre-clinical developments.

  13. Temporoparietal cortex in aphasia. Evidence from positron emission tomography

    SciTech Connect

    Metter, E.J.; Hanson, W.R.; Jackson, C.A.; Kempler, D.; van Lancker, D.; Mazziotta, J.C.; Phelps, M.E. )

    1990-11-01

    Forty-four aphasic patients were examined with (F18)-fluorodeoxyglucose positron emission tomography in a resting state to determine whether consistent glucose metabolic abnormalities were present. Ninety-seven percent of subjects showed metabolic abnormalities in the angular gyrus, 89% in the supramarginal gyrus, and 87% in the lateral and transverse superior temporal gyrus. Pearson product moment correlations were calculated between regional metabolic measures and performance on the Western Aphasia Battery. No significant correlations were found between the Western Aphasia Battery scores and right hemisphere metabolic measures. Most left hemisphere regions correlated with more than one score from the Western Aphasia Battery. Temporal but not frontal regions had significant correlations to the comprehension score. The left temporoparietal region was consistently affected in these subjects, suggesting that common features in the aphasias were caused by left temporoparietal dysfunction, while behavioral differences resulted from (1) the extent of temporoparietal changes, and (2) dysfunction elsewhere in the brain, particularly the left frontal and subcortical areas.

  14. Tau Positron Emission Tomography (PET) Imaging: Past, Present, and Future.

    PubMed

    Ariza, Manuela; Kolb, Hartmuth C; Moechars, Dieder; Rombouts, Frederik; Andrés, José Ignacio

    2015-06-11

    Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common cause of dementia among the elderly population. The good correlation of the density and neocortical spread of neurofibrillary tangles (NFTs) with clinical AD disease progression offers an opportunity for the early diagnosis and staging using a noninvasive imaging technique such as positron emission tomography (PET). Thus, PET imaging of NFTs not only holds promise as a diagnostic tool but also may enable the development of disease modifying therapeutics for AD. In this review, we focus on the structural diversity of tau PET tracers, the challenges related to the identification of high affinity and highly selective NFT ligands, and recent progress in the clinical development of tau PET radioligands.

  15. 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

  16. Practical implementation of tetrahedral mesh reconstruction in emission tomography

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

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

    2013-05-07

    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

  18. 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.

  19. Positron emission tomography as a diagnostic tool in oncology.

    PubMed

    Schiepers, C; Hoh, C K

    1998-01-01

    Early diagnosis in oncology is important for treatment by surgical intervention, which generally has the highest curative potential. For higher stages of disease involvement, initiation of rapid treatment is indicated to provide the patient with the optimal therapy regimen. Although this may not improve the prognosis, it will maintain the quality of life. Anatomic imaging modalities, such as CT, MR imaging, and US, are clinically important high-resolution imaging techniques that are well suited to reveal structural abnormalities. However, the differentiation of lesions as being benign or malignant is still problematic. Metabolic imaging modalities in nuclear medicine (NM), i.e., single photon emission computed tomography (SPECT) and positron emission tomography (PET), can reveal biochemical parameters of the lesions such as glucose, oxygen, or amino acid metabolism, or measure the receptor density status. These parameters may allow a completely new clinical perspective in the management and understanding of diseases such as cancer. Although PET has been around since the early 1960s, it has only recently emerged as a powerful diagnostic tool in oncology. Society has great difficulty accepting this clinical imaging modality because of its high cost and complexity. Current applications of PET in oncology have been in characterizing lesions, differentiating recurrent disease from treatment effects, staging tumors, evaluating the extent of disease, and therapy monitoring. Here, the role of PET in diagnosis, staging, and restaging of cancer is reviewed and compared with the other tumor imaging modalities. We cover articles published in the past 3 years. We utilize the typical radiology format, in which the contribution in each body area is reviewed (topographic orientation), instead of the more organ-based approach used in internal medicine.

  20. 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.

  1. Positron emission tomography: the contribution of cognitive activation paradigms to the understanding of the epilepsies.

    PubMed

    Swartz, B E; Mandelkern, M A

    1999-01-01

    Cognitive activation paradigms coupled with positron emission tomographic techniques may aid in the identification of functional and epileptogenic zones for presurgical evaluation. More work is needed to determine the most clinically efficacious paradigms for different seizure types. The real strength of activation positron emission tomography lies in the ability to study shifts in cognitive circuitry that accompany a fixed neuropathologic entity for both groups of similar subjects and individuals. These techniques are enhancing our understanding of the fundamentals of brain plasticity and may be used in the future to predict precise surgical risks.

  2. Existing Pittsburgh Compound-B positron emission tomography thresholds are too high: statistical and pathological evaluation.

    PubMed

    Villeneuve, Sylvia; Rabinovici, Gil D; Cohn-Sheehy, Brendan I; Madison, Cindee; Ayakta, Nagehan; Ghosh, Pia M; La Joie, Renaud; Arthur-Bentil, Samia Kate; Vogel, Jacob W; Marks, Shawn M; Lehmann, Manja; Rosen, Howard J; Reed, Bruce; Olichney, John; Boxer, Adam L; Miller, Bruce L; Borys, Ewa; Jin, Lee-Way; Huang, Eric J; Grinberg, Lea T; DeCarli, Charles; Seeley, William W; Jagust, William

    2015-07-01

    Amyloid-β, a hallmark of Alzheimer's disease, begins accumulating up to two decades before the onset of dementia, and can be detected in vivo applying amyloid-β positron emission tomography tracers such as carbon-11-labelled Pittsburgh compound-B. A variety of thresholds have been applied in the literature to define Pittsburgh compound-B positron emission tomography positivity, but the ability of these thresholds to detect early amyloid-β deposition is unknown, and validation studies comparing Pittsburgh compound-B thresholds to post-mortem amyloid burden are lacking. In this study we first derived thresholds for amyloid positron emission tomography positivity using Pittsburgh compound-B positron emission tomography in 154 cognitively normal older adults with four complementary approaches: (i) reference values from a young control group aged between 20 and 30 years; (ii) a Gaussian mixture model that assigned each subject a probability of being amyloid-β-positive or amyloid-β-negative based on Pittsburgh compound-B index uptake; (iii) a k-means cluster approach that clustered subjects into amyloid-β-positive or amyloid-β-negative based on Pittsburgh compound-B uptake in different brain regions (features); and (iv) an iterative voxel-based analysis that further explored the spatial pattern of early amyloid-β positron emission tomography signal. Next, we tested the sensitivity and specificity of the derived thresholds in 50 individuals who underwent Pittsburgh compound-B positron emission tomography during life and brain autopsy (mean time positron emission tomography to autopsy 3.1 ± 1.8 years). Amyloid at autopsy was classified using Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria, unadjusted for age. The analytic approaches yielded low thresholds (standard uptake value ratiolow = 1.21, distribution volume ratiolow = 1.08) that represent the earliest detectable Pittsburgh compound-B signal, as well as high thresholds (standard

  3. [Ventricular volumes determined by single-photon emission computed tomography].

    PubMed

    Katohno, E; Ono, K; Owada, K; Fujino, A; Watanabe, N; Sato, M; Konno, I; Yaoita, H; Tsuda, F; Kariyone, S

    1987-06-01

    To determine right (RV) and left ventricular (LV) volumes, a new technique was developed using ECG-gated single-photon emission computed tomography (SPECT). RV volumes of nine patients and LV volumes of 22 patients measured by SPECT and biplane contrast cineangiography were compared. In addition, volume and ejection fraction (EF) of the RV and LV were obtained by SPECT for 10 normal controls, 21 patients with old myocardial infarction (OMI), eight patients with hypertrophic cardiomyopathy (HCM) and 12 patients with dilated cardiomyopathy (DCM), and these results were compared. The intracardiac blood pool was labeled with Tc-99m sodium pertechnetate and 32 images were recorded through 180 degrees by a rotating gamma-camera. End-diastolic and end-systolic counts during 50 msec were recorded during 50 or 60 cardiac cycles. These counting data were reconstructed as tomographic images of vertical long-axial slices with thickness of a pixel without any attenuation correction. The numbers of voxels within the % cut-off level were summed, and the sum was multiplied by the one voxel volume. The cut-off level for ventricular delineation was determined as 45% by phantom studies. 1. The values obtained from SPECT and contrast angiography correlated well. 2. In normal controls, LV end-diastolic and end-systolic volumes were significantly less than those of the RV (p less than 0.05, p less than 0.001) and LVEF was significantly greater than the RVEF (p less than 0.001). 3. In OMI (single vessel disease), both end-diastolic and end-systolic volumes of the LV were significantly greater than those of normals (p less than 0.01, p less than 0.001) and LVEF was significantly less. In HCM end-systolic volumes of the RV were significantly less (p less than 0.05) than those of the normals. 4. LV volume was greater and LVEF was extremely low both in DCM and in OMI (multivessel disease) compared to that of the normals. In DCM, RV end-systolic volumes was greater and RVEF was lower than

  4. The role of single-photon emission computed tomography/computed tomography in benign and malignant bone disease.

    PubMed

    Horger, Marius; Bares, Roland

    2006-10-01

    Radiological (plain radiographs, computed tomography [CT], magnetic resonance imaging [MRI]) and nuclear medicine methods (bone scan, leukocyte scan) both provide unique information about the status of the skeleton. Both have typical strengths and weaknesses, which often lead to the sequential use of different procedures in daily routine. This use causes the unnecessary loss of time and sometimes money, if redundant information is obtained without establishing a final diagnosis. Recently, new devices for hybrid imaging (single-photon emission computed tomography/computed tomography [SPECT/CT], positron emission tomography/computed tomography [PET/CT]) were introduced, which allow for direct fusion of morphological (CT) and functional (SPECT, PET) data sets. With regard to skeletal abnormalities, this approach appears to be extremely useful because it combines the advantages of both techniques (high-resolution imaging of bone morphology and high sensitivity imaging of bone metabolism). By the accurate correlation of both, a new quality of bone imaging has now become accessible. Although researchers undertaking the initial studies exclusively used low-dose CT equipment, a new generation of SPECT/CT devices has emerged recently. By integrating high-resolution spiral CT, quality of bone imaging may improve once more. Ongoing prospective studies will have to show whether completely new diagnostic algorithms will come up for classification of bone disease as a consequence of this development. Besides, the role of ultrasonography and MRI for bone and soft-tissue imaging also will have to be re-evaluated. Looking at the final aim of all imaging techniques--to achieve correct diagnosis in a fast, noninvasive, comprehensive, and inexpensive way--we are now on the edge of a new era of multimodality imaging that will probably change the paths and structure of medicine in many ways. Presently, hybrid imaging using SPECT/CT has been proven to increase sensitivity and specificity

  5. [18F]fluorodeoxyglucose positron emission tomography predicts survival after chemoimmunotherapy for primary mediastinal large B-cell lymphoma: results of the International Extranodal Lymphoma Study Group IELSG-26 Study.

    PubMed

    Martelli, Maurizio; Ceriani, Luca; Zucca, Emanuele; Zinzani, Pier Luigi; Ferreri, Andrés J M; Vitolo, Umberto; Stelitano, Caterina; Brusamolino, Ercole; Cabras, Maria Giuseppina; Rigacci, Luigi; Balzarotti, Monica; Salvi, Flavia; Montoto, Silvia; Lopez-Guillermo, Armando; Finolezzi, Erica; Pileri, Stefano A; Davies, Andrew; Cavalli, Franco; Giovanella, Luca; Johnson, Peter W M

    2014-06-10

    To assess the role of [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) after rituximab and anthracycline-containing chemoimmunotherapy in patients with primary mediastinal large B-cell lymphoma (PMLBCL). Among 125 patients prospectively enrolled, 115 were eligible for central review of PET/CT scans at the completion of standard chemoimmunotherapy, by using a five-point scale. Consolidation radiotherapy (RT) was permitted and given to 102 patients. Fifty-four patients (47%) achieved a complete metabolic response (CMR), defined as a completely negative scan or with residual [18F]FDG activity below the mediastinal blood pool (MBP) uptake. In the remaining 61 patients (53%), the residual uptake was higher than MBP uptake but below the liver uptake in 27 (23%), slightly higher than the liver uptake in 24 (21%), and markedly higher in 10 (9%). CMR after chemoimmunotherapy predicted higher 5-year progression-free survival (PFS; 98% v 82%; P=.0044) and overall survival (OS; 100% v 91%; P=.0298). Patients with residual uptake higher than MBP uptake but below liver uptake had equally good outcomes without any recurrence. Using the liver uptake as cutoff for PET positivity (boundary of score, 3 to 4) discriminated most effectively between high or low risk of failure, with 5-year PFS of 99% versus 68% (P<.001) and 5-year OS of 100% versus 83% (P<.001). More than 90% of patients are projected to be alive and progression-free at 5 years, despite a low CMR rate (47%) after chemoimmunotherapy. This study provides a basis for using PET/CT to define the role of RT in PMLBCL. © 2014 by American Society of Clinical Oncology.

  6. Validation of VASO cerebral blood volume measurement with positron emission tomography.

    PubMed

    Uh, Jinsoo; Lin, Ai-Ling; Lee, Kihak; Liu, Peiying; Fox, Peter; Lu, Hanzhang

    2011-03-01

    Cerebral blood volume (CBV) has been shown to be an important biomarker in a number of neurological disorders and in the quantitative interpretation of functional MRI. One approach to determine CBV in humans is vascular-space-occupancy MRI, and this technique has been applied to the studies of brain glioma, Schizophrenia, and Alzheimer's disease. However, validation of this technique with a gold standard method has not been reported. In this study, we compared vascular-space-occupancy MRI with a radiotracer-based positron emission tomography technique in a group of healthy subjects. It was found that regional CBV measured with vascular-space-occupancy MRI was highly correlated with that of the positron emission tomography data (R=0.79±0.10, N=8). Furthermore, absolute CBV values quantified by vascular-space-occupancy were also in excellent agreement with those by positron emission tomography (slope=1.00±0.15). Because of the differences in the labeling principles between the two modalities, systematic CBV differences were observed in large vessel and ventricle regions. Copyright © 2010 Wiley-Liss, Inc.

  7. Variation in radiotherapy target volume definition, dose to organs at risk and clinical target volumes using anatomic (computed tomography) versus combined anatomic and molecular imaging (positron emission tomography/computed tomography): intensity-modulated radiotherapy delivered using a tomotherapy Hi Art machine: final results of the VortigERN study.

    PubMed

    Chatterjee, S; Frew, J; Mott, J; McCallum, H; Stevenson, P; Maxwell, R; Wilsdon, J; Kelly, C G

    2012-12-01

    Contrast-enhanced computed tomography (CECT) is the current standard for delineating tumours of the head and neck for radiotherapy. Although metabolic imaging with positron emission tomography (PET) has been used in recent years, the studies were non-confirmatory in establishing its routine role in radiotherapy planning in the modern era. This study explored the difference in gross tumour volume and clinical target volume definitions for the primary and nodal volumes when FDG PET/CT was used as compared with CECT in oropharyngeal cancer cases. Twenty patients with oropharyngeal cancers had a PET/CT scan in the treatment position after consent. Target volumes were defined on CECT scans by a consultant clinical oncologist who was blind to the PET scans. After obtaining inputs from a radiologist, another set of target volumes were outlined on the PET/CT data set. The gross and clinical target volumes as defined on the two data sets were then analysed. The hypothesis of more accurate target delineation, preventing geographical miss and comparative overlap volumes between CECT and PET/CT, was explored. The study also analysed the volumes of intersection and analysed whether there was any TNM stage migration when PET/CT was used as compared with CECT for planning. In 17 of 20 patients, the TNM stage was not altered when adding FDG PET information to CT. PET information prevented geographical miss in two patients and identified distant metastases in one case. PET/CT gross tumour volumes were smaller than CECT volumes (mean ± standard deviation: 25.16 cm(3) ± 35.8 versus 36.56 cm(3) ± 44.14; P < 0.015) for the primary tumour. Interestingly, our study showed no significant differences in gross tumour volume for T1/T2 disease, although differences in gross tumour volumes for advanced disease (T3/T4) were significant. The nodal target volumes (mean ± standard deviation: CECT versus PET/CT 32.48 cm(3) ± 36.63 versus 32.21 cm(3) ± 37.09; P > 0.86) were not statistically

  8. Early postischemic hyperperfusion: pathophysiologic insights from positron emission tomography.

    PubMed

    Marchal, G; Young, A R; Baron, J C

    1999-05-01

    Early postischemic hyperperfusion (EPIH) has long been documented in animal stroke models and is the hallmark of efficient recanalization of the occluded artery with subsequent reperfusion of the tissue (although occasionally it may be seen in areas bordering the hypoperfused area during arterial occlusion). In experimental stroke, early reperfusion has been reported to both prevent infarct growth and aggravate edema formation and hemorrhage, depending on the severity and duration of prior ischemia and the efficiency of reperfusion, whereas neuronal damage with or without enlarged infarction also may result from reperfusion (so-called "reperfusion injury"). In humans, focal hyperperfusion in the subacute stage (i.e., more than 48 hours after onset) has been associated with tissue necrosis in most instances, but regarding the acute stage, its occurrence, its relations with tissue metabolism and viability, and its clinical prognostic value were poorly understood before the advent of positron emission tomography (PET), in part because of methodologic issues. By measuring both CBF and metabolism, PET is an ideal imaging modality to study the pathophysiologic mechanism of EPIH. Although only a few PET studies have been performed in the acute stage that have systematically assessed tissue and clinical outcome in relation to EPIH, they have provided important insights. In one study, about one third of the patients with first-ever middle cerebral artery (MCA) territory stroke studied within 5 to 18 hours after symptom onset exhibited EPIH. In most cases, EPIH affected large parts of the cortical MCA territory in a patchy fashion, together with abnormal vasodilation (increased cerebral blood volume), "luxury perfusion" (decreased oxygen extraction fraction), and mildly increased CMRO2, which was interpreted as postischemic rebound of cellular metabolism in structurally preserved tissue. In that study, the spontaneous outcome of the tissue exhibiting EPIH was good, with late

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

    SciTech Connect

    Berker, Yannick Li, Yusheng

    2016-02-15

    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. 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

  11. Preliminary clinical study in patients with hemispatial neglect after stroke by neglect test battery and 99mTc-ECD single-photon emission computed tomography.

    PubMed

    Yin, Yafu; Li, Xuena; Li, Yaming; Gu, Hui; Han, Chunqi; Liu, Hao

    2009-05-01

    To explore the presence, clinical characteristics, anatomical foci in image and mechanism of hemispatial neglect (HSN), neglect test battery and single-photon emission computed tomography (SPECT) regional cerebral blood flow (rCBF) imaging were performed on patients with stroke. Thirty dextromanual patients who were diagnosed as having unilateral stroke clinically were recruited. A neglect test battery including line bisection test, star cancellation test and drawing test was performed on the subjects. The severity of neglect was measured on neglect tests. The lowest rCBF, the range with decreased rCBF, number of the foci with decreased rCBF, the flow deficit size and the total number of pixels in the foci were measured on SPECT rCBF imaging. Twenty-five patients were diagnosed as having HSN by the neglect test battery. Contralateral neglect (CN) and ipsilateral neglect (IN) were observed in both right and left hemisphere strokes. On SPECT imaging, the patients with neglect had decreased rCBF in the frontal cortex most often; followed by the parietal, occipital and temporal cortices; and basal ganglia and thalamus in some cases. The patients who had two or more regions damaged showed neglect more often and severity. The correlation coefficients between rCBF in the foci, the decreased percentage of rCBF of the foci and the severity of neglect were -0.119 (P>.05) and 0.221 (P>.05). The correlation coefficients between the range, number of foci, the flow deficit size, the total number of pixels of the foci and the severity of neglect were 0.537 (P<.05), 0.493 (P<.05), 0.561 (P<.05), 0.466 (P<.05), respectively. No difference between CN and IN on SPECT images reached statistical significance. The severity of neglect did not correlate with rCBF and the decreased percentage of rCBF in the foci, while it was significantly correlated with the range, number of foci, the flow deficit size and the total numbers of pixels of the foci significantly. And the patients with CN and

  12. Clinical applications of positron emission tomography/computed tomography treatment planning.

    PubMed

    Macapinlac, Homer A

    2008-03-01

    Positron emission tomography/computed tomography (PET/CT) has provided an incremental dimension to the management of cancer patients by allowing the incorporation of important molecular images in radiotherapy treatment planning, ie, direct evaluation of tumor metabolism, cell proliferation, apoptosis, hypoxia, and angiogenesis. The CT component allows 4D imaging techniques, allowing improvements in the accuracy of treatment delivery by compensating for tumor/normal organ motion, improving PET quantification, and correcting PET and CT image misregistration. The combination of PET and CT in a single imaging system to obtain a fused anatomical and functional image data is now emerging as a promising tool in radiotherapy departments for improved delineation of tumor volumes and optimization of treatment plans. PET has the potential to improve radiotherapy planning by minimizing unnecessary irradiation of normal tissues and by reducing the risk of geographic miss. PET influences treatment planning in a high proportion of cases and therefore radiotherapy dose escalation without PET may be futile. This article examines the increasing role of hybrid PET/CT imaging techniques in process of improving treatment planning in oncology with emphasis on non small cell lung cancer.

  13. Quality Assurance of Positron Emission Tomography/Computed Tomography for Radiation Therapy

    SciTech Connect

    Xing Lei

    2008-05-01

    Recent advances in radiation delivery techniques, such as intensity-modulated radiation therapy, provide unprecedented ability to exquisitely control three-dimensional dose distribution. Development of on-board imaging and other image-guidance methods significantly improved our ability to better target a radiation beam to the tumor volume. However, in reality, accurate definition of the location and boundary of the tumor target is still problematic. Biologic and physiologic imaging promises to solve the problem in a fundamental way and has a more and more important role in patient staging, treatment planning, and therapeutic assessment in radiation therapy clinics. The last decade witnessed a dramatic increase in the use of positron emission tomography and computed tomography in radiotherapy practice. To ensure safe and effective use of nuclide imaging, a rigorous quality assurance (QA) protocol of the imaging tools and integration of the imaging data must be in place. The application of nuclide imaging in radiation oncology occurs at different levels of sophistication. Quantitative use of the imaging data in treatment planning through image registration and standardized uptake value calculation is often involved. Thus, QA should not be limited to the performance of the scanner, but should also include the process of implementing image data in treatment planning, such as data transfer, image registration, and quantitation of data for delineation of tumors and sensitive structures. This presentation di