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Sample records for high-resolution positron emission

  1. High resolution and high speed positron emission tomography data acquisition

    International Nuclear Information System (INIS)

    Burgiss, S.G.; Byars, L.G.; Jones, W.F.; Casey, M.E.

    1986-01-01

    High resolution positron emission tomography (PET) requires many detectors. Thus, data collection systems for PET must have high data rates, wide data paths, and large memories to histogram the events. This design uses the VMEbus to cost effectively provide these features. It provides for several modes of operation including real time sorting, list mode data storage, and replay of stored list mode data

  2. New detector developments for high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Ziegler, S.I.; Pichler, B.; Lorenz, E.

    1998-01-01

    The strength of quantitative, functional imaging using positron emission tomography, specially in small animals, is limited due to the spatial resolution. Therefore, various tomograph designs employing new scintillators, light sensors, or coincidence electronic are investigated to improve resolution without losses in sensitivity. Luminous scintillators with short light decay time in combination with novel readout schemes using photomultipliers or semiconductor detectors are currently tested by several groups and are implemented in tomographs for small animals. This review summarises the state of development in high resolution positron emission tomography with a detailed description of a system incorporating avalanche photodiode arrays and small scintillation crystals. (orig.) [de

  3. Detectors for high resolution dynamic positron emission tomography

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Budinger, T.F.; Huesman, R.H.

    1985-01-01

    Tomography is the technique of producing a photographic image of an opaque specimen by transmitting a beam of x-rays or gamma rays through the specimen onto an adjacent photographic film. The image results from variations in thickness, density, and chemical composition, of the specimen. This technique is used to study the metabolism of the human brain. This article examines the design of equipment used for high resolution dynamic positron emission tomography. 27 references, 5 figures, 3 tables

  4. Towards high-resolution positron emission tomography for small volumes

    International Nuclear Information System (INIS)

    McKee, B.T.A.

    1982-01-01

    Some arguments are made regarding the medical usefulness of high spatial resolution in positron imaging, even if limited to small imaged volumes. Then the intrinsic limitations to spatial resolution in positron imaging are discussed. The project to build a small-volume, high resolution animal research prototype (SHARP) positron imaging system is described. The components of the system, particularly the detectors, are presented and brief mention is made of data acquisition and image reconstruction methods. Finally, some preliminary imaging results are presented; a pair of isolated point sources and 18 F in the bones of a rabbit. Although the detector system is not fully completed, these first results indicate that the goals of high sensitivity and high resolution (4 mm) have been realized. (Auth.)

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

    Science.gov (United States)

    Budinger, T. F.; Derenzo, S. E.; Huesman, R. H.; Jagust, W. J.; Valk, P. E.

    1989-09-01

    One of the unexpected fruits of basic physics research and the computer revolution is the noninvasive imaging power available to today's physician. Technologies that were strictly the province of research scientists only a decade or two ago now serve as the foundations for such standard diagnostic tools as x-ray computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), ultrasound, single photon emission computed tomography (SPECT), and positron emission tomography (PET). Furthermore, prompted by the needs of both the practicing physician and the clinical researcher, efforts to improve these technologies continue. This booklet endeavors to describe the advantages of achieving high resolution in PET imaging.

  6. High resolution positron tomography

    International Nuclear Information System (INIS)

    Brownell, G.L.; Burnham, C.A.

    1982-01-01

    The limits of spatial resolution in practical positron tomography are examined. The four factors that limit spatial resolution are: positron range; small angle deviation; detector dimensions and properties; statistics. Of these factors, positron range may be considered the fundamental physical limitation since it is independent of instrument properties. The other factors are to a greater or lesser extent dependent on the design of the tomograph

  7. Study on a high resolution positron emission tomography scanner for brain study

    International Nuclear Information System (INIS)

    Nohara, N.; Tomitani, T.; Yamamoto, M.; Murayama, H.; Tanaka, E.

    1990-01-01

    The spatial resolution of positron emission tomography (PET) scanners is usually limited by the finite size of crystals such as bismuth germanate (BGO). To attain high resolution as well as high sensitivity, it is essential to use a large number of small BGO crystals arranged in close-packing on circular rings. In developing high resolution PET scanners, however, there are two physical factors limiting the spatial resolution. One is the finite range of positrons before annihilation and the other the deviation from 180 degrees of annihilation photons. The effect of the factors on the spatial resolution has been evaluated for positron-emitting sources as a function of detector ring radius. A high resolution PET scanner has been developed for brain study, aiming to have spatial resolutions as high as less than 4-mm FWHM in tomographic plane and less than 6-mm FWHM in axial direction at the detector ring center. For the goal of the high resolutions a multi-segment type of photomultiplier tubes has been specially designed and developed, which allows one tube to be directly coupled by four BGO crystals. The scanner consists of five detector rings of 47-cm in diameter, using all 1200 BGO crystals each measuring 5 mm x 12 mm x 30 mm. The scanner provides simultaneous 9 images by combination of in-plane and cross-plane, offering a 24-cm dia. x7.4-cm field-of-view. Physical performance of the scanner was investigated. At the ring center, the spatial resolution in the tomographic plane was measured to be 3.5-mm FWHM. The axial resolution was measured to be 5.7-mm FWHM for in-plane and 5.3-mm FWHM for cross-plane. Sensitivity for a 20-cm dia. uniform source was measured to be 9.5 kcps/μCi/ml for in-plane and 15.3 kcps/μCi/ml for cross-plane. (J.P.N.)

  8. Detector response restoration in image reconstruction of high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Liang, Z.

    1994-01-01

    A mathematical method was studied to model the detector response of high spatial-resolution positron emission tomography systems consisting of close-packed small crystals, and to restore the resolution deteriorated due to crystal penetration and/or nonuniform sampling across the field-of-view (FOV). The simulated detector system had 600 bismuth germanate crystals of 3.14 mm width and 30 mm length packed on a single ring of 60 cm diameter. The space between crystal was filled up with lead. Each crystal was in coincidence with 200 opposite crystals so that the FOV had a radius of 30 cm. The detector response was modeled based on the attenuating properties of the crystals and the septa, as well as the geometry of the detector system. The modeled detector-response function was used to restore the projections from the sinogram of the ring-detector system. The restored projections had a uniform sampling of 1.57 mm across the FOV. The crystal penetration and/or the nonuniform sampling were compensated in the projections. A penalized maximum-likelihood algorithm was employed to accomplish the restoration. The restored projections were then filtered and backprojected to reconstruct the image. A chest phantom with a few small circular ''cold'' objects located at the center and near the periphery of FOV was computer generated and used to test the restoration. The reconstructed images from the restored projections demonstrated resolution improvement off the FOV center, while preserving the resolution near the center

  9. Initial characterization of a BGO-photodiode detector for high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Derenzo, S.E.

    1983-11-01

    Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon photodiodes (SPDs) for crystal identification, and coupled in groups to phototubes (PMTs) for coincidence timing. A 3 mm x 3 mm x 3 mm BGO crystal coupled only to an SPD can achieve a 511 keV photopeak resolution of 8.7% FWHM at -150 0 C, using a pulse peaking time of 10 μs. When two 3 mm x 3 mm x 15 mm BGO crystals are coupled individually to SPDs and also coupled to a common 14 mm diam PMT, the SPDs detect the 511 keV photopeak with a resolution of 30% FWHM at -76 0 C. In coincidence with an opposing 3 mm wide BGO crystal, the SPDs are able to identify the crystal of interaction with good signal-to-noise ratio, and the detector pair resolution is 2 mm FWHM. 32 references, 7 figures, 3 tables

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

    International Nuclear Information System (INIS)

    Knesaurek, K.; Machac, J.; Vallabhajosula, S.; Buchsbaum, M.S.

    1996-01-01

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

  11. Use of a YAP:Ce matrix coupled to a position-sensitive photomultiplier for high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Del Guerra, A.; Zavattini, G.; Notaristefani, F. de; Giganti, M.; Piffanelli, A.; Pani, R.; Turra, A.

    1996-01-01

    A new scintillation detector system has been designed for application in high resolution Positron Emission Tomography (PET). The detector is a bundle of small YAlO 3 :Ce (YAP) crystals closely packed (0.2 x 0.2 x 3.0 cm 3 ), coupled to a position sensitive photomultiplier tube (PSPMT). The preliminary results obtained for spatial resolution, time resolution, energy resolution and efficiency of two such detectors working in coincidence are presented. These are 1.2 mm for the FWHM spatial resolution, 2.0 ns for the FWHM time resolution and 20% for the FWHM energy resolution at 511 keV. The measured efficiency is (44 ± 3)% with a 150 keV threshold and (20 ± 2)% with a 300 keV threshold

  12. Development of high-resolution detector module with depth of interaction identification for positron emission tomography

    International Nuclear Information System (INIS)

    Niknejad, Tahereh; Pizzichemi, Marco; Stringhini, Gianluca; Auffray, Etiennette; Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino; Ferramacho, Luis; Lecoq, Paul; Leong, Carlos; Paganoni, Marco; Rolo, Manuel; Silva, Rui; Silveira, Miguel; Tavernier, Stefaan; Varela, Joao; Zorraquino, Carlos

    2017-01-01

    We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm"3 matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

  13. Development of high-resolution detector module with depth of interaction identification for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Niknejad, Tahereh, E-mail: tniknejad@lip.pt [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Pizzichemi, Marco [University of Milano-Bicocca (Italy); Stringhini, Gianluca [University of Milano-Bicocca (Italy); CERN, Geneve (Switzerland); Auffray, Etiennette [CERN, Geneve (Switzerland); Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Ferramacho, Luis [PETsys Electronics, Oeiras (Portugal); Lecoq, Paul [CERN, Geneve (Switzerland); Leong, Carlos [PETsys Electronics, Oeiras (Portugal); Paganoni, Marco [University of Milano-Bicocca (Italy); Rolo, Manuel [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); INFN, Turin (Italy); Silva, Rui [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Silveira, Miguel [PETsys Electronics, Oeiras (Portugal); Tavernier, Stefaan [PETsys Electronics, Oeiras (Portugal); Vrije Universiteit Brussel (Belgium); Varela, Joao [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); CERN, Geneve (Switzerland); Zorraquino, Carlos [Biomedical Image Technologies Lab, Universidad Politécnica de Madrid (Spain); CIBER-BBN, Universidad Politécnica de Madrid (Spain)

    2017-02-11

    We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm{sup 3} matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

  14. Effects of system geometry and other physical factors on photon sensitivity of high-resolution positron emission tomography

    Science.gov (United States)

    Habte, F.; Foudray, A. M. K.; Olcott, P. D.; Levin, C. S.

    2007-07-01

    We are studying two new detector technologies that directly measure the three-dimensional coordinates of 511 keV photon interactions for high-resolution positron emission tomography (PET) systems designed for small animal and breast imaging. These detectors are based on (1) lutetium oxyorthosilicate (LSO) scintillation crystal arrays coupled to position-sensitive avalanche photodiodes (PSAPD) and (2) cadmium zinc telluride (CZT). The detectors have excellent measured 511 keV photon energy resolutions (oriented 'edge-on' with respect to incoming 511 keV annihilation photons and arranged to form a compact FOV with detectors very close to, or in contact with, the subject tissues. In this paper, we used Monte Carlo simulation to study various factors that limit the photon sensitivity of a high-resolution PET system dedicated to small animal imaging. To optimize the photon sensitivity, we studied several possible system geometries for a fixed 8 cm transaxial and 8 cm axial FOV. We found that using rectangular-shaped detectors arranged into a cylindrical geometry does not yield the best photon sensitivity. This is due to the fact that forming rectangular-shaped detectors into a ring produces significant wedge-shaped inter-module gaps, through which Compton-scattered photons in the detector can escape. This effect limits the center point source photon sensitivity to 8% photon sensitivity for the LSO-PSAPD box configuration and >15% for CZT box geometry, using a 350-650 keV energy window setting. These simulation results compare well with analytical estimations. The trend is different for a clinical whole-body PET system that uses conventional LSO-PMT block detectors with larger crystal elements. Simulations predict roughly the same sensitivity for both box and cylindrical detector configurations. This results from the fact that a large system diameter (>80 cm) results in relatively small inter-module gaps in clinical whole-body PET. In addition, the relatively large block

  15. Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals

    Energy Technology Data Exchange (ETDEWEB)

    Brix, G. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany); Doll, J. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany); Bellemann, M.E. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany); Trojan, H. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany); Haberkorn, U. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany); Schmidlin, P. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany); Ostertag, H. [Research Program ``Radiological Diagnostics and Therapy``, German Cancer Research Center (DKFZ), Heidelberg (Germany)

    1997-07-01

    The purpose of this work was to improve of the spatial resolution of a whole-body PET system for experimental studies of small animals by incorporation of scanner characteristics into the process of iterative image reconstruction. The image-forming characteristics of the PET camera were characterized by a spatially variant line-spread function (LSF), which was determined from 49 activated copper-64 line sources positioned over a field of view (FOV) of 21.0 cm. During the course of iterative image reconstruction, the forward projection of the estimated image was blurred with the LSF at each iteration step before the estimated projections were compared with the measured projections. Moreover, imaging studies of a rat and two nude mice were performed to evaluate the imaging properties of our approach in vivo. The spatial resolution of the scanner perpendicular to the direction of projection could be approximated by a one-dimensional Gaussian-shaped LSF with a full-width at half-maximum increasing from 6.5 mm at the centre to 6.7 mm at a radial distance of 10.5 cm. The incorporation of this blurring kernel into the iteration formula resulted in a significantly improved spatial resolution of about 3.9 mm over the examined FOV. As demonstrated by the phantom and the animal experiments, the high-resolution algorithm not only led to a better contrast resolution in the reconstructed emission scans but also improved the accuracy for quantitating activity concentrations in small tissue structures without leading to an amplification of image noise or image mottle. The presented data-handling strategy incorporates the image restoration step directly into the process of algebraic image reconstruction and obviates the need for ill-conditioned ``deconvolution`` procedures to be performed on the projections or on the reconstructed image. In our experience, the proposed algorithm is of special interest in experimental studies of small animals. (orig./AJ). With 9 figs.

  16. Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals

    International Nuclear Information System (INIS)

    Brix, G.; Doll, J.; Bellemann, M.E.; Trojan, H.; Haberkorn, U.; Schmidlin, P.; Ostertag, H.

    1997-01-01

    The purpose of this work was to improve of the spatial resolution of a whole-body PET system for experimental studies of small animals by incorporation of scanner characteristics into the process of iterative image reconstruction. The image-forming characteristics of the PET camera were characterized by a spatially variant line-spread function (LSF), which was determined from 49 activated copper-64 line sources positioned over a field of view (FOV) of 21.0 cm. During the course of iterative image reconstruction, the forward projection of the estimated image was blurred with the LSF at each iteration step before the estimated projections were compared with the measured projections. Moreover, imaging studies of a rat and two nude mice were performed to evaluate the imaging properties of our approach in vivo. The spatial resolution of the scanner perpendicular to the direction of projection could be approximated by a one-dimensional Gaussian-shaped LSF with a full-width at half-maximum increasing from 6.5 mm at the centre to 6.7 mm at a radial distance of 10.5 cm. The incorporation of this blurring kernel into the iteration formula resulted in a significantly improved spatial resolution of about 3.9 mm over the examined FOV. As demonstrated by the phantom and the animal experiments, the high-resolution algorithm not only led to a better contrast resolution in the reconstructed emission scans but also improved the accuracy for quantitating activity concentrations in small tissue structures without leading to an amplification of image noise or image mottle. The presented data-handling strategy incorporates the image restoration step directly into the process of algebraic image reconstruction and obviates the need for ill-conditioned ''deconvolution'' procedures to be performed on the projections or on the reconstructed image. In our experience, the proposed algorithm is of special interest in experimental studies of small animals. (orig./AJ). With 9 figs

  17. High resolution computed tomography of positron emitters

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Budinger, T.F.; Cahoon, J.L.; Huesman, R.H.; Jackson, H.G.

    1976-10-01

    High resolution computed transaxial radionuclide tomography has been performed on phantoms containing positron-emitting isotopes. The imaging system consisted of two opposing groups of eight NaI(Tl) crystals 8 mm x 30 mm x 50 mm deep and the phantoms were rotated to measure coincident events along 8960 projection integrals as they would be measured by a 280-crystal ring system now under construction. The spatial resolution in the reconstructed images is 7.5 mm FWHM at the center of the ring and approximately 11 mm FWHM at a radius of 10 cm. We present measurements of imaging and background rates under various operating conditions. Based on these measurements, the full 280-crystal system will image 10,000 events per sec with 400 μCi in a section 1 cm thick and 20 cm in diameter. We show that 1.5 million events are sufficient to reliably image 3.5-mm hot spots with 14-mm center-to-center spacing and isolated 9-mm diameter cold spots in phantoms 15 to 20 cm in diameter

  18. Test-retest variability of high resolution positron emission tomography (PET) imaging of cortical serotonin (5HT2A) receptors in older, healthy adults

    International Nuclear Information System (INIS)

    Chow, Tiffany W; Mamo, David C; Uchida, Hiroyuki; Graff-Guerrero, Ariel; Houle, Sylvain; Smith, Gwenn S; Pollock, Bruce G; Mulsant, Benoit H

    2009-01-01

    Position emission tomography (PET) imaging using [ 18 F]-setoperone to quantify cortical 5-HT 2A receptors has the potential to inform pharmacological treatments for geriatric depression and dementia. Prior reports indicate a significant normal aging effect on serotonin 5HT 2A receptor (5HT 2A R) binding potential. The purpose of this study was to assess the test-retest variability of [ 18 F]-setoperone PET with a high resolution scanner (HRRT) for measuring 5HT 2A R availability in subjects greater than 60 years old. Methods: Six healthy subjects (age range = 65–78 years) completed two [ 18 F]-setoperone PET scans on two separate occasions 5–16 weeks apart. The average difference in the binding potential (BP ND ) as measured on the two occasions in the frontal and temporal cortical regions ranged between 2 and 12%, with the lowest intraclass correlation coefficient in anterior cingulate regions. We conclude that the test-retest variability of [ 18 F]-setoperone PET in elderly subjects is comparable to that of [ 18 F]-setoperone and other 5HT 2A R radiotracers in younger subject samples

  19. High resolution Cerenkov light imaging of induced positron distribution in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Fujii, Kento; Morishita, Yuki; Okumura, Satoshi; Komori, Masataka [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Aichi 461-8673 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Aichi 462-8508 (Japan)

    2014-11-01

    Purpose: In proton therapy, imaging of the positron distribution produced by fragmentation during or soon after proton irradiation is a useful method to monitor the proton range. Although positron emission tomography (PET) is typically used for this imaging, its spatial resolution is limited. Cerenkov light imaging is a new molecular imaging technology that detects the visible photons that are produced from high-speed electrons using a high sensitivity optical camera. Because its inherent spatial resolution is much higher than PET, the authors can measure more precise information of the proton-induced positron distribution with Cerenkov light imaging technology. For this purpose, they conducted Cerenkov light imaging of induced positron distribution in proton therapy. Methods: First, the authors evaluated the spatial resolution of our Cerenkov light imaging system with a {sup 22}Na point source for the actual imaging setup. Then the transparent acrylic phantoms (100 × 100 × 100 mm{sup 3}) were irradiated with two different proton energies using a spot scanning proton therapy system. Cerenkov light imaging of each phantom was conducted using a high sensitivity electron multiplied charge coupled device (EM-CCD) camera. Results: The Cerenkov light’s spatial resolution for the setup was 0.76 ± 0.6 mm FWHM. They obtained high resolution Cerenkov light images of the positron distributions in the phantoms for two different proton energies and made fused images of the reference images and the Cerenkov light images. The depths of the positron distribution in the phantoms from the Cerenkov light images were almost identical to the simulation results. The decay curves derived from the region-of-interests (ROIs) set on the Cerenkov light images revealed that Cerenkov light images can be used for estimating the half-life of the radionuclide components of positrons. Conclusions: High resolution Cerenkov light imaging of proton-induced positron distribution was possible. The

  20. High resolution Cerenkov light imaging of induced positron distribution in proton therapy

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi; Fujii, Kento; Morishita, Yuki; Okumura, Satoshi; Komori, Masataka; Toshito, Toshiyuki

    2014-01-01

    Purpose: In proton therapy, imaging of the positron distribution produced by fragmentation during or soon after proton irradiation is a useful method to monitor the proton range. Although positron emission tomography (PET) is typically used for this imaging, its spatial resolution is limited. Cerenkov light imaging is a new molecular imaging technology that detects the visible photons that are produced from high-speed electrons using a high sensitivity optical camera. Because its inherent spatial resolution is much higher than PET, the authors can measure more precise information of the proton-induced positron distribution with Cerenkov light imaging technology. For this purpose, they conducted Cerenkov light imaging of induced positron distribution in proton therapy. Methods: First, the authors evaluated the spatial resolution of our Cerenkov light imaging system with a 22 Na point source for the actual imaging setup. Then the transparent acrylic phantoms (100 × 100 × 100 mm 3 ) were irradiated with two different proton energies using a spot scanning proton therapy system. Cerenkov light imaging of each phantom was conducted using a high sensitivity electron multiplied charge coupled device (EM-CCD) camera. Results: The Cerenkov light’s spatial resolution for the setup was 0.76 ± 0.6 mm FWHM. They obtained high resolution Cerenkov light images of the positron distributions in the phantoms for two different proton energies and made fused images of the reference images and the Cerenkov light images. The depths of the positron distribution in the phantoms from the Cerenkov light images were almost identical to the simulation results. The decay curves derived from the region-of-interests (ROIs) set on the Cerenkov light images revealed that Cerenkov light images can be used for estimating the half-life of the radionuclide components of positrons. Conclusions: High resolution Cerenkov light imaging of proton-induced positron distribution was possible. The authors

  1. Positron emission tomography

    International Nuclear Information System (INIS)

    Reivich, M.; Alavi, A.

    1985-01-01

    This book contains 24 selections. Some of the titles are: Positron Emission Tomography Instrumentation, Generator Systems for Positron Emitters, Reconstruction Algorithms, Cerebral Glucose Consumption: Methodology and Validation, Cerebral Blood Flow Tomography Using Xenon-133 Inhalation: Methods and Clinical Applications, PET Studies of Stroke, Cardiac Positron Emission Tomography, and Use of PET in Oncology

  2. High-resolution(18)F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging for pituitary adenoma detection in Cushing disease.

    Science.gov (United States)

    Chittiboina, Prashant; Montgomery, Blake K; Millo, Corina; Herscovitch, Peter; Lonser, Russell R

    2015-04-01

    OBJECT High-resolution PET (hrPET) performed using a high-resolution research tomograph is reported as having a resolution of 2 mm and could be used to detect corticotroph adenomas through uptake of(18)F-fluorodeoxyglucose ((18)F-FDG). To determine the sensitivity of this imaging modality, the authors compared(18)F-FDG hrPET and MRI detection of pituitary adenomas in Cushing disease (CD). METHODS Consecutive patients with CD who underwent preoperative(18)F-FDG hrPET and MRI (spin echo [SE] and spoiled gradient recalled [SPGR] sequences) were prospectively analyzed. Standardized uptake values (SUVs) were calculated from hrPET and were compared with MRI findings. Imaging findings were correlated to operative and histological findings. RESULTS Ten patients (7 females and 3 males) were included (mean age 30.8 ± 19.3 years; range 11-59 years). MRI revealed a pituitary adenoma in 4 patients (40% of patients) on SE and 7 patients (70%) on SPGR sequences.(18)F-FDG hrPET demonstrated increased(18)F-FDG uptake consistent with an adenoma in 4 patients (40%; adenoma size range 3-14 mm). Maximum SUV was significantly higher for(18)F-FDG hrPET-positive tumors (difference = 5.1, 95% CI 2.1-8.1; p = 0.004) than for(18)F-FDG hrPET-negative tumors.(18)F-FDG hrPET positivity was not associated with tumor volume (p = 0.2) or dural invasion (p = 0.5). Midnight and morning ACTH levels were associated with(18)F-FDG hrPET positivity (p = 0.01 and 0.04, respectively) and correlated with the maximum SUV (R = 0.9; p = 0.001) and average SUV (R = 0.8; p = 0.01). All(18)F-FDG hrPET-positive adenomas had a less than a 180% ACTH increase and(18)F-FDG hrPET-negative adenomas had a greater than 180% ACTH increase after CRH stimulation (p = 0.03). Three adenomas were detected on SPGR MRI sequences that were not detected by(18)F-FDG hrPET imaging. Two adenomas not detected on SE (but no adenomas not detected on SPGR) were detected on(18)F-FDG hrPET. CONCLUSIONS While(18)F-FDG hrPET imaging can

  3. Positron emission tomography

    International Nuclear Information System (INIS)

    Iio, Masahiro

    1982-01-01

    Utilization of positron emission tomography was reviewed in relation to construction and planned construction of small-size medical cyclotrons, planned construction of positron cameras and utilization of short-lived radionuclides. (Chiba, N.)

  4. Instrumentation for positron emission tomography

    International Nuclear Information System (INIS)

    Budinger, T.F.; Derenzo, S.E.; Huesman, R.H.

    1984-01-01

    Positron emission tomography with a spatial resolution of 2 mm full width at half maximum for quantitation in regions of interest 4 mm in diameter will become possible with the development of detectors that achieve ultrahigh resolution. Improved resolution will be possible using solid-state photodetectors for crystal identification or photomultiplier tubes with many small electron multipliers. Temporal resolution of 2 seconds and gating of cyclic events can be accomplished if statistical requirements are met. The major physical considerations in achieving high-resolution positron emission tomography are the degradation in resolution resulting from positron range, emission angle, parallax error, detector sampling density, the sensitivity of various detector materials and packing schemes, and the tradeoff between temporal resolution and statistical accuracy. The accuracy of data required for physiological models depends primarily on the fidelity of spatial sampling independent of statistical constraints

  5. Positron emission tomography imaging--technical considerations

    International Nuclear Information System (INIS)

    Muehllehner, G.; Karp, J.S.

    1986-01-01

    Positron imaging instrumentation has improved rapidly in the last few years. Scanners currently under development are beginning to approach fundamental limits set by positron range and noncolinearity effects. This report reviews the latest developments in positron emission tomography (PET) instrumentation, emphasizing the development of coding schemes that reduce the complexity and cost of high-resolution scanners. The relative benefits of using time-of-flight (TOF) information is discussed as well. 68 references

  6. Cardiac positron emission tomography

    International Nuclear Information System (INIS)

    Eftekhari, M.; Ejmalian, G.

    2003-01-01

    Positron emission tomography is an intrinsically tool that provide a unique and unparalleled approach for clinicians and researchers to interrogate the heart noninvasively. The ability to label substances of physiological interest with positron-emitting radioisotopes has permitted insight into normal blood flow and metabolism and the alterations that occur with disease states. Positron emission tomography of the heart has evolved as a unique, noninvasive approach for the assessment of myocardial perfusion, metabolism, and function. Because of the intrinsic quantitative nature of positron emission tomography measurements as well as the diverse compounds that can be labeled with positron- emitting radioisotopes, studies with positron emission tomography have provided rich insight into the physiology of the heart under diverse conditions

  7. Positron emission tomography

    International Nuclear Information System (INIS)

    Paans, A.M.J.

    1981-01-01

    Positron emitting radiopharmaceuticals have special applications in in-vivo studies of biochemical processes. The combination of a cyclotron for the production of radionuclides and a positron emission tomograph for the registration of the distribution of radioactivity in the body enables the measurement of local radioactivity concentration in tissues, and opens up new possibilities in the diagnosis and examination of abnormalities in the metabolism. The principles and procedures of positron emission tomography are described and the necessary apparatus considered, with emphasis on the positron camera. The first clinical applications using 55 Co bloemycine for tumor detection are presented. (C.F.)

  8. Improvement in the detection of locoregional recurrence in head and neck malignancies: F-18 fluorodeoxyglucose-positron emission tomography/computed tomography compared to high-resolution contrast-enhanced computed tomography and endoscopic examination.

    Science.gov (United States)

    Rangaswamy, Balasubramanya; Fardanesh, M Reza; Genden, Eric M; Park, Eunice E; Fatterpekar, Girish; Patel, Zara; Kim, Jongho; Som, Peter M; Kostakoglu, Lale

    2013-11-01

    To compare the diagnostic efficacy of positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG-PET)/computed tomography (CT) to that of contrast-enhanced high-resolution CT (HRCT) and assess the value of a combinatorial approach in detection of recurrent squamous cell cancer of the head and neck (HNC) and to assess the efficacy of FDG-PET/CT with and without HRCT in comparison to standard-of-care follow-up--physical examination (PE) and endoscopy (E)--in determination of locally recurrent HNC. Retrospective study. A total of 103 patients with HNC underwent FDG-PET/CT and neck HRCT. There were two groups of patients: Group A had an FDG-PET study acquired with low-dose CT, and group B had an FDG-PET study acquired with HRCT. The PET data obtained with or without HRCT were compared on a lesion and patient basis with the results of the PE/E. On a lesion basis, both groups combined had higher sensitivity and negative predictive value (NPV) than the HRCT. Specificity and positive predictive value (PPV) for group B were higher than for group A. On a patient basis, both groups combined had a higher sensitivity and NPV than PE/E, respectively, although specificity of PE/E was higher than that of either group. PET data obtained with either protocol directly influenced treatment. HRCT increases the specificity and PPV of PET/CT when acquired simultaneously with PET. FDG-PET/CT acquired with either LDCT or HRCT has higher accuracy than HRCT alone and increases the sensitivity and NPV of PE/E. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  9. Positron emission tomography

    NARCIS (Netherlands)

    Paans, AMJ

    Positron Emission Tomography (PET) is a method for determining biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides as C-11, N-13, O-15 and F-18 and by measuring the annihilation radiation using a

  10. Positron emission computed tomography

    International Nuclear Information System (INIS)

    Grover, M.; Schelbert, H.R.

    1985-01-01

    Regional mycardial blood flow and substrate metabolism can be non-invasively evaluated and quantified with positron emission computed tomography (Positron-CT). Tracers of exogenous glucose utilization and fatty acid metabolism are available and have been extensively tested. Specific tracer kinetic models have been developed or are being tested so that glucose and fatty acid metabolism can be measured quantitatively by Positron-CT. Tracers of amino acid and oxygen metabolism are utilized in Positron-CT studies of the brain and development of such tracers for cardiac studies are in progress. Methods to quantify regional myocardial blood flow are also being developed. Previous studies have demonstrated the ability of Positron-/CT to document myocardial infarction. Experimental and clinical studies have begun to identify metabolic markers of reversibly ischemic myocardium. The potential of Positron-CT to reliably detect potentially salvageable myocardium and, hence, to identify appropriate therapeutic interventions is one of the most exciting applications of the technique

  11. Positron emission tomography

    International Nuclear Information System (INIS)

    Chandrasekhar, Preethi; Himabindu, Pucha

    2000-01-01

    Positron Emission Tomography (PET) is a non-invasive nuclear imaging technique used to study different molecular pathways and anatomical structures. PET has found extensive applications in various fields of medicine viz. cardiology, oncology, psychiatry/psychology, neuro science and pulmonology. This study paper basically deals with the physics, chemistry and biology behind the PET technique. It discusses the methodology for generation of the radiotracers responsible for emission of positrons and the annihilation and detection techniques. (author)

  12. Positron emission tomography

    International Nuclear Information System (INIS)

    Dvorak, O.

    1989-01-01

    The principle is briefly described of positron emission tomography, and its benefits and constraints are listed. It is emphasized that positron emission tomography (PET) provides valuable information on metabolic changes in the organism that are otherwise only very difficult to obtain, such as brain diagnosis including relationships between mental disorders and the physiology and pathophysiology of the brain. A PET machine is to be installed in Czechoslovakia in the near future. (L.O.)

  13. Positron emission tomography

    International Nuclear Information System (INIS)

    Wienhard, K.; Heiss, W.D.

    1984-01-01

    The principles and selected clinical applications of positron emission tomography are described. In this technique a chemical compound is labeled with a positron emitting isotope and its biochemical pathway is traced by coincidence detection of the two annihilation photons. The application of the techniques of computed tomography allows to reconstruct the spatial distribution of the radioactivity within a subject. The 18 F-deoxyglucose method for quantitative measurement of local glucose metabolism is discussed in order to illustrate the possibilities of positron emission tomography to record physiological processes in vivo. (orig.) [de

  14. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI.

    Science.gov (United States)

    Yoon, Haesung; Yoon, Dahye; Yun, Mijin; Choi, Ji Soo; Park, Vivian Youngjean; Kim, Eun-Kyung; Jeong, Joon; Koo, Ja Seung; Yoon, Jung Hyun; Moon, Hee Jung; Kim, Suhkmann; Kim, Min Jung

    2016-01-01

    Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters. Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32-75 years) with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1) were suspicious for malignancy on mammography or ultrasound (US), 2) were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB) 3) underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) and positron emission tomography-computed tomography (PET-CT), and 4) had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER), maximum standardized FDG uptake value (SUV max), apparent diffusion coefficient (ADC), and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA) to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters. In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in all cases. Multiple metabolites showed

  15. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI.

    Directory of Open Access Journals (Sweden)

    Haesung Yoon

    Full Text Available Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS magnetic resonance spectroscopy (MRS and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters.Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32-75 years with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1 were suspicious for malignancy on mammography or ultrasound (US, 2 were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB 3 underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE and diffusion-weighted imaging (DWI and positron emission tomography-computed tomography (PET-CT, and 4 had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER, maximum standardized FDG uptake value (SUV max, apparent diffusion coefficient (ADC, and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters.In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in all cases. Multiple metabolites

  16. High-resolution tomography of positron emitters with clustered pinhole SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Goorden, Marlies C; Beekman, Freek J [Section of Radiation Detection and Medical Imaging, Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)], E-mail: m.c.goorden@tudelft.nl

    2010-03-07

    State-of-the-art small-animal single photon emission computed tomography (SPECT) enables sub-half-mm resolution imaging of radio-labelled molecules. Due to severe photon penetration through pinhole edges, current multi-pinhole SPECT is not suitable for high-resolution imaging of photons with high energies, such as the annihilation photons emitted by positron emitting tracers (511 keV). To deal with this edge penetration, we introduce here clustered multi-pinhole SPECT (CMP): each pinhole in a cluster has a narrow opening angle to reduce photon penetration. Using simulations, CMP is compared with (i) a collimator with traditional pinholes that is currently used for sub-half-mm imaging of SPECT isotopes (U-SPECT-II), and (ii), like (i) but with collimator thickness adapted to image high-energy photons (traditional multi-pinhole SPECT, TMP). At 511 keV, U-SPECT-II is able to resolve the 0.9 mm rods of an iteratively reconstructed Jaszczak-like capillary hot rod phantom, and while TMP only leads to small improvements, CMP can resolve rods as small as 0.7 mm. Using a digital tumour phantom, we show that CMP resolves many details not assessable with standard USPECT-II and TMP collimators. Furthermore, CMP makes it possible to visualize uptake of positron emitting tracers in sub-compartments of a digital mouse striatal brain phantom. This may open up unique possibilities for analysing processes such as those underlying the function of neurotransmitter systems. Additional potential of CMP may include (i) the imaging of other high-energy single-photon emitters (e.g. I-131) and (ii) localized imaging of positron emitting tracers simultaneously with single photon emitters, with an even better resolution than coincidence PET.

  17. Positron emission tomography

    International Nuclear Information System (INIS)

    Yamamoto, Y.L.; Thompson, C.J.; Diksic, M.; Meyer, E.; Feindel, W.H.

    1984-01-01

    One of the most exciting new technologies introduced in the last 10 yr is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body. This approach is analogous to quantitative in-vivo autoradiography but has the added advantage of permitting non-invasive in vivo studies. PET scanning requires a small cyclotron to produce short-lived positron emitting isotopes such as oxygen-15, carbon-11, nitrogen-13 and fluorine-18. Proper radiochemical facilities and advanced computer equipment are also needed. Most important, PET requires a multidisciplinary scientific team of physicists, radiochemists, mathematicians, biochemists and physicians. The most recent trends are reviewed in the imaging technology, radiochemistry, methodology and clinical applications of positron emission tomography. (author)

  18. Positron emission tomography

    International Nuclear Information System (INIS)

    Pavuk, M.

    2003-12-01

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

  19. Positron emission tomography

    CERN Document Server

    Paans, A M J

    2006-01-01

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

  20. Tomography by positrons emission

    International Nuclear Information System (INIS)

    Mosconi, Sergio L.

    1999-01-01

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

  1. Positron emission tomography. Positronemisionstomografi

    Energy Technology Data Exchange (ETDEWEB)

    Bolwig, T G; Haunsoe, S; Dahlgaard Hove, J; Hesse, B; Hoejgard, L; Jensen, M; Paulson, O B; Hastrup Svendsen, J; Soelvsten Soerensen, S

    1994-10-01

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

  2. Positron emission tomography

    International Nuclear Information System (INIS)

    Bolwig, T.G.; Haunsoe, S.; Dahlgaard Hove, J.; Hesse, B.; Hoejgard, L.; Jensen, M.; Paulson, O.B.; Hastrup Svendsen, J.; Soelvsten Soerensen, S.

    1994-01-01

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

  3. Positron emission tomography

    International Nuclear Information System (INIS)

    Marchenkov, N.S.

    2000-01-01

    The foundations of the positron emission tomography (PET), widely used for the medical diagnostics, are considered. The brief description of the cyclotron for production of radionuclides, applied in the PET, the target devices for manufacturing the position emitters, the moduli for the radiopharmaceuticals synthesis (RPS) for the PET is presented. The necessity and concept of complete automation of the RPS for the PET are discussed [ru

  4. Positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lindback, Stig [GEMS PET Systems AB, Uppsala (Sweden)

    1995-07-15

    Positron Emission Tomography (PET) is an advanced nuclear medicine technique used for research at major centres. Unique diagnostic information is obtained from tomographic measurements of the biochemistry and physiology of tissues and organs. In theory, diseases are related to biochemical changes and these can be observed with PET long before any anatomical changes are detectable. In PET the radioactive component is a positron-emitting isotope or 'tracer'. The positrons annihilate with electrons in the body to produce two gamma rays 180° apart; coincidence detection of these gammas provides a very efficient method of determining the spatial distribution of the radioisotope tracer. Because physiological measurements are usually required in a single imaging session, very short-lived isotopes are used to label the tracer molecules; isotope production and labelling is usually carried out in situ. The most commonly used radionuclides are carbon- 11 (half-life 20 minutes), nitrogen-13 (10 minutes), oxygen-15 (2 minutes), and fluorine-18 (110 minutes). A PET system has three major components: - a particle accelerator with targets for production of the positron-emitting isotopes; - chemistry modules for synthesis and labelling of the desired tracers; - and a PET camera for in-vivo measurements of the distribution of the tracer in the body.

  5. Positron emission tomography

    International Nuclear Information System (INIS)

    Lindback, Stig

    1995-01-01

    Positron Emission Tomography (PET) is an advanced nuclear medicine technique used for research at major centres. Unique diagnostic information is obtained from tomographic measurements of the biochemistry and physiology of tissues and organs. In theory, diseases are related to biochemical changes and these can be observed with PET long before any anatomical changes are detectable. In PET the radioactive component is a positron-emitting isotope or 'tracer'. The positrons annihilate with electrons in the body to produce two gamma rays 180° apart; coincidence detection of these gammas provides a very efficient method of determining the spatial distribution of the radioisotope tracer. Because physiological measurements are usually required in a single imaging session, very short-lived isotopes are used to label the tracer molecules; isotope production and labelling is usually carried out in situ. The most commonly used radionuclides are carbon- 11 (half-life 20 minutes), nitrogen-13 (10 minutes), oxygen-15 (2 minutes), and fluorine-18 (110 minutes). A PET system has three major components: - a particle accelerator with targets for production of the positron-emitting isotopes; - chemistry modules for synthesis and labelling of the desired tracers; - and a PET camera for in-vivo measurements of the distribution of the tracer in the body

  6. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each ring contains a plurality of scintillation detectors which are positioned around an inner circumference with a septum ring extending inwardly from the inner circumference along each outer edge of each ring. An additional septum ring is positioned in the middle of each ring of detectors and parallel to the other septa rings, whereby the inward extent of all the septa rings may be reduced by one-half and the number of detectors required in each ring is reduced. The additional septa reduces the costs of the positron camera and improves its performance

  7. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each detector ring or offset ring includes a plurality of photomultiplier tubes and a plurality of scintillation crystals are positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring is offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. The offset detector ring geometry reduces the costs of the positron camera and improves its performance

  8. Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    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

  9. Positron Emission Tomography (PET)

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Positron Emission Tomography (PET)

    Science.gov (United States)

    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.

  11. High-resolution mapping of motor vehicle carbon dioxide emissions

    Science.gov (United States)

    McDonald, Brian C.; McBride, Zoe C.; Martin, Elliot W.; Harley, Robert A.

    2014-05-01

    A fuel-based inventory for vehicle emissions is presented for carbon dioxide (CO2) and mapped at various spatial resolutions (10 km, 4 km, 1 km, and 500 m) using fuel sales and traffic count data. The mapping is done separately for gasoline-powered vehicles and heavy-duty diesel trucks. Emission estimates from this study are compared with the Emissions Database for Global Atmospheric Research (EDGAR) and VULCAN. All three inventories agree at the national level within 5%. EDGAR uses road density as a surrogate to apportion vehicle emissions, which leads to 20-80% overestimates of on-road CO2 emissions in the largest U.S. cities. High-resolution emission maps are presented for Los Angeles, New York City, San Francisco-San Jose, Houston, and Dallas-Fort Worth. Sharp emission gradients that exist near major highways are not apparent when emissions are mapped at 10 km resolution. High CO2 emission fluxes over highways become apparent at grid resolutions of 1 km and finer. Temporal variations in vehicle emissions are characterized using extensive day- and time-specific traffic count data and are described over diurnal, day of week, and seasonal time scales. Clear differences are observed when comparing light- and heavy-duty vehicle traffic patterns and comparing urban and rural areas. Decadal emission trends were analyzed from 2000 to 2007 when traffic volumes were increasing and a more recent period (2007-2010) when traffic volumes declined due to recession. We found large nonuniform changes in on-road CO2 emissions over a period of 5 years, highlighting the importance of timely updates to motor vehicle emission inventories.

  12. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector planes positioned side-by-side around a patient area to detect radiation. Each plane includes a plurality of photomultiplier tubes and at least two rows of scintillation crystals on each photomultiplier tube extend across to adjacent photomultiplier tubes for detecting radiation from the patient area. Each row of crystals on each photomultiplier tube is offset from the other rows of crystals, and the area of each crystal on each tube in each row is different than the area of the crystals on the tube in other rows for detecting which crystal is actuated and allowing the detector to detect more inter-plane slides. The crystals are offset by an amount equal to the length of the crystal divided by the number of rows. The rows of crystals on opposite sides of the patient may be rotated 90 degrees relative to each other

  13. Positron emission tomography. Basic principles

    International Nuclear Information System (INIS)

    Rodriguez, Jose Luis; Massardo, Teresa; Gonzalez, Patricio

    2001-01-01

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

  14. Rostrocaudal gradients of dopamine D2/3 receptor binding in striatal subregions measured with [11C]raclopride and high-resolution positron emission tomography

    DEFF Research Database (Denmark)

    Alakurtti, Kati; Johansson, Jarkko J; Tuokkola, Terhi

    2013-01-01

    scanned with brain-dedicated high-resolution research tomography (HRRT, Siemens Medical Solutions, Knoxville, TN, USA) and [(11)C]raclopride. Coronally defined regions of interest (ROIs) of the caudate nucleus, putamen and ventral striatum (VST) were sampled plane-by-plane, 1.5mm apart, on spatially...... observed in the VST. The novelty of this study lies in the presentation, for the first time, of the D2/3 receptor binding gradients in each striatal subregion in the brains of living healthy humans. The high spatial resolution provided by HRRT enables frequent sampling of BPND along the longitudinal extent...

  15. Fundamentals of positron emission tomography

    International Nuclear Information System (INIS)

    Ostertag, H.

    1989-01-01

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

  16. Positron emission tomography in oncology

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This report describes the current and potential uses of positron emission tomography in clinical medicine and research related to oncology. Assessment will be possible of metabolism and physiology of tumors and their effects on adjacent tissues. Specific probes are likely to be developed for target sites on tumors, including monoclonal antibodies and specific growth factors that recognize tumors. To date, most oncological applications of positron emission tomography tracers have been qualitative; in the future, quantitative metabolic measurements should aid in the evaluation of tumor biology and response to treatment

  17. NMF on positron emission tomography

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  18. High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

    NARCIS (Netherlands)

    Groot, F.M.F. de

    2000-01-01

    In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption

  19. The metabolism of the human brain studied with positron emission tomography

    International Nuclear Information System (INIS)

    Greitz, T.; Ingvar, D.H.; Widen, L.

    1985-01-01

    This volume presents coverage of the use of positron emission tomography (PET) to study the human brain. The contributors assess new developments in high-resolution positron emission tomography, cyclotrons, radiochemistry, and tracer kinetic models, and explore the use of PET in brain energy metabolism, blood flow, and protein synthesis measurements, receptor analysis, and pH determinations, In addition, they discuss the relevance and applications of positron emission tomography from the perspectives of physiology, neurology, and psychiatry

  20. Imaging of dopamine transporters in rats using high-resolution pinhole single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Booij, Jan; Bruin, Kora de; Habraken, Jan B.A. [Department of Nuclear Medicine, F2N, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Voorn, Pieter [Department of Anatomy, Vrije Universiteit Medical Center, Amsterdam (Netherlands)

    2002-09-01

    To date, the vast majority of investigations on the dopaminergic system in small animals have been in vitro studies. In comparison with in vitro studies, single-photon emission tomography (SPET) or positron emission tomography (PET) imaging of the dopaminergic system in small animals has the advantage of permitting repeated studies within the same group of animals. Dopamine transporter imaging is a valuable non-invasive tool with which to investigate the integrity of dopaminergic neurons. The purpose of this study was to investigate the feasibility of assessing dopamine transporter density semi-quantitatively in rats using a recently developed high-resolution pinhole SPET system. This system was built exclusively for imaging of small animals. In this unique single-pinhole system, the animal rotates instead of the collimated detector. The system has proven to have a high spatial resolution. We performed SPET imaging with [{sup 123}I]FP-CIT to quantify striatal dopamine transporters in rat brain. In all seven studied control rats, symmetrical striatal binding to dopamine transporters was seen 2 h after injection of the radiotracer, with striatal-to-cerebellar binding ratios of approximately 3.5. In addition, test/retest variability of the striatal-to-cerebellar binding ratios was studied and found to be 14.5%. Finally, in unilaterally 6-hydroxydopamine-lesioned rats, striatal binding was only visible on the non-lesioned side. Quantitative analysis revealed that striatal-to-cerebellar SPET ratios were significantly lower on the lesioned (mean binding ratio 2.2{+-}0.2) than on the non-lesioned (mean ratio 3.1{+-}0.4) side. The preliminary results of this study indicate that semi-quantitative assessment of striatal dopamine transporter density using our recently developed high-resolution single-pinhole SPET system is feasible in living rat brain. (orig.)

  1. A prototype high-resolution animal positron tomograph with avalanche photodiode arrays and LSO crystals

    International Nuclear Information System (INIS)

    Ziegler, S.I.; Pichler, B.J.; Rafecas, M.; Schwaiger, M.

    2001-01-01

    To fully utilize positron emission tomography (PET) as a non-invasive tool for tissue characterization, dedicated instrumentation is being developed which is specially suited for imaging mice and rats. Semiconductor detectors, such as avalanche photodiodes (APDs), may offer an alternative to photomultiplier tubes for the readout of scintillation crystals. Since the scintillation characteristics of lutetium oxyorthosilicate (LSO) are well matched to APDs, the combination of LSO and APDs seems favourable, and the goal of this study was to build a positron tomograph with LSO-APD modules to prove the feasibility of such an approach. A prototype PET scanner based on APD readout of small, individual LSO crystals was developed for tracer studies in mice and rats. The tomograph consists of two sectors (86 mm distance), each comprising three LSO-APD modules, which can be rotated for the acquisition of complete projections. In each module, small LSO crystals (3.7 x 3.7 x 12 mm 3 ) are individually coupled to one channel within matrices containing 2 x 8 square APDs (2.6 x 2.6 mm 2 sensitive area per channel). The list-mode data are reconstructed with a penalized weighted least squares algorithm which includes the spatially dependent line spread function of the tomograph. Basic performance parameters were measured with phantoms and first experiments with rats and mice were conducted to introduce this methodology for biomedical imaging. The reconstructed field of view covers 68 mm, which is 80% of the total detector diameter. Image resolution was shown to be 2.4 mm within the whole reconstructed field of view. Using a lower energy threshold of 450 keV, the system sensitivity was 350 Hz/MBq for a line source in air in the centre of the field of view. In a water-filled cylinder of 4.6 cm diameter, the scatter fraction at the centre of the field of view was 16% (450 keV threshold). The count rate was linear up to 700 coincidence counts per second. In vivo studies of anaesthetized

  2. Study of CT-based positron range correction in high resolution 3D PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cal-Gonzalez, J., E-mail: jacobo@nuclear.fis.ucm.es [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Herraiz, J.L. [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Espana, S. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Vicente, E. [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain); Herranz, E. [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Desco, M. [Unidad de Medicina y Cirugia Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain); Vaquero, J.J. [Dpto. de Bioingenieria e Ingenieria Espacial, Universidad Carlos III, Madrid (Spain); Udias, J.M. [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain)

    2011-08-21

    Positron range limits the spatial resolution of PET images and has a different effect for different isotopes and positron propagation materials. Therefore it is important to consider it during image reconstruction, in order to obtain optimal image quality. Positron range distributions for most common isotopes used in PET in different materials were computed using the Monte Carlo simulations with PeneloPET. The range profiles were introduced into the 3D OSEM image reconstruction software FIRST and employed to blur the image either in the forward projection or in the forward and backward projection. The blurring introduced takes into account the different materials in which the positron propagates. Information on these materials may be obtained, for instance, from a segmentation of a CT image. The results of introducing positron blurring in both forward and backward projection operations was compared to using it only during forward projection. Further, the effect of different shapes of positron range profile in the quality of the reconstructed images with positron range correction was studied. For high positron energy isotopes, the reconstructed images show significant improvement in spatial resolution when positron range is taken into account during reconstruction, compared to reconstructions without positron range modeling.

  3. Study of CT-based positron range correction in high resolution 3D PET imaging

    International Nuclear Information System (INIS)

    Cal-Gonzalez, J.; Herraiz, J.L.; Espana, S.; Vicente, E.; Herranz, E.; Desco, M.; Vaquero, J.J.; Udias, J.M.

    2011-01-01

    Positron range limits the spatial resolution of PET images and has a different effect for different isotopes and positron propagation materials. Therefore it is important to consider it during image reconstruction, in order to obtain optimal image quality. Positron range distributions for most common isotopes used in PET in different materials were computed using the Monte Carlo simulations with PeneloPET. The range profiles were introduced into the 3D OSEM image reconstruction software FIRST and employed to blur the image either in the forward projection or in the forward and backward projection. The blurring introduced takes into account the different materials in which the positron propagates. Information on these materials may be obtained, for instance, from a segmentation of a CT image. The results of introducing positron blurring in both forward and backward projection operations was compared to using it only during forward projection. Further, the effect of different shapes of positron range profile in the quality of the reconstructed images with positron range correction was studied. For high positron energy isotopes, the reconstructed images show significant improvement in spatial resolution when positron range is taken into account during reconstruction, compared to reconstructions without positron range modeling.

  4. Positron emission tomography takes lead

    International Nuclear Information System (INIS)

    Simms, R.

    1989-01-01

    Positron emission tomography (PET)'s ability to detect functional abnormalities before they manifest anatomically is examined and some of its most common applications are outlined. It is emphasised that when PET facility and Australian Nuclear Science and Technology Organization's national cyclotron are established at the Royal Prince Alfred Hospital, the availability of short-lived tracers such as oxygen 15, nitrogen 13 and fluorine 18 would improve the specificity of tests(e.g. for brain tumors or cardiac viability) further. Construction of the cyclotron will start shortly and is due to be completed and operating by the end of 1991

  5. Characteristics of Biogenic VOCs Emission and its High-Resolution Emission Inventory in China

    Science.gov (United States)

    Li, L.; Li, Y.; Xie, S.

    2017-12-01

    Biogenic volatile organic compounds (BVOCs), with high emission and reactivity, can have substantial impacts on the haze and photochemical pollution. It is essential to establish an accurate high-resolution BVOC emission inventory in China for air quality simulation and decision making. Firstly, a semi-static enclosure technique is developed for the field measurements of BVOC emission rates from 50 plant species in China. Using the GC-MS/FID system, 103 VOC species for each plant species are measured. Based on the field measurements in our study and the reported emission rates at home and abroad, a methodology for determining the emission categories of BVOCs is developed using statistical analysis. The isoprene and monoterpene emission rates of 192 plant species/genera in China are determined based on the above emission categories. Secondly, a new vegetation classification with 82 plant functional types (PFTs) is developed based on the most detailed and latest vegetation investigations, China's official statistical data and Vegetation Atlas of China (1:1,000,000). The leaf biomass is estimated based on provincial vegetation volume and production with biomass-apportion models. The WRF model is used to determine meteorological variables at a high spatio-temporal resolution. Using MEAGNv2.1 and the determined emission rates in our study, the high-resolution emission inventories of isoprene, 37 monoterpene species, 32 sesquiterpene species, and other VOCs (OVOCs) from 82 PFTs in China for 1981-2013 are established. The total annual BVOC emissions in 2013 are 55.88 Tg, including 33.87 Tg isoprene, 6.36 Tg monoterpene, 1.29 Tg sesquiterpene, and 14.37 Tg OVOCs. The distribution of isoprene emission fluxes is consistent with the distribution of broadleaf trees, especially tree species with high or higher emission potential. During 1981-2013, China's BVOC emissions have increased by 47.48% at an average rate of 1.80% yr-1. Emissions of isoprene have the largest enhancement

  6. Positron emission tomography of the heart

    International Nuclear Information System (INIS)

    Budinger, T.F.; Yano, Y.; Mathis, C.A.; Moyer, B.R.; Huesman, R.H.; Derenzo, S.E.

    1983-01-01

    Positron emission tomography (PET) offers the opportunity to noninvasively measure heart muscle blood perfusion, oxygen utilization, metabolism of fatty acids, sugars and amino acids. This paper reviews physiological principles which are basic to PET instrumentation for imaging the heart and gives examples of the application of positron emission tomography for measuring myocardial flow and metabolism. 33 references, 11 figures, 1 table

  7. Improved positron emission tomography camera

    International Nuclear Information System (INIS)

    Mullani, N.A.

    1986-01-01

    A positron emission tomography camera having a plurality of rings of detectors positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom, and a plurality of scintillation crystals positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring may be offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. (author)

  8. Positron emission tomography and migraine

    International Nuclear Information System (INIS)

    Chabriat, H.

    1992-01-01

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

  9. Positron emission tomography basic sciences

    CERN Document Server

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

    2003-01-01

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

  10. Positron emission tomography in oncology

    International Nuclear Information System (INIS)

    Lecomte, R.; Bentourkia, M.; Benard, F.

    2002-01-01

    Positron Emission Tomography is a sophisticated molecular imaging technique, using a special scanner, that displays the functional status of tissues in the body at the cellular level (their metabolism). It is a diagnostic scan that provides the physician with information not available with traditional anatomic studies such as CT or MRI. PET can detect changes in cell function (disease) long before they are evident as physical (anatomic) changes seen on CT or MRI. In this way PET can add important information about many diseases allowing the physician to make a diagnosis often much earlier than with anatomic imaging techniques such as CT or MRI alone. In addition, in cases where an abnormality is noted on CT or MRI, PET can help differentiate benign changes from changes due to disease. PET scanning also typically images the entire body, unlike CT/MRI which is usually broken up into specific limited body section scans. All cells use glucose as an energy source but cancer cells use much more since they are growing much faster and out of control. This is the basis of imaging with F-18 FDG glucose, the radiotracer agent use in a PET oncology study. The abnormal, accelerated glucose used by cancer cells is detected by the PET scanner that processes the emissions from the F-18 FDG glucose by abnormally high levels of metabolism (tumor)

  11. Scintillators for positron emission tomography

    International Nuclear Information System (INIS)

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

    1995-09-01

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

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

    Science.gov (United States)

    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.

  13. Positron emission tomography in neuropsychology.

    Science.gov (United States)

    Heiss, W D; Herholz, K; Pawlik, G; Wagner, R; Wienhard, K

    1986-01-01

    By positron emission tomography (PET) of 18F-2-fluoro-2-deoxy-D-glucose (FDG) local cerebral metabolic rate for glucose (LCMRGl) can be measured in man. Normal values in cerebral cortex and basal ganglia range from 35 to 50 mumol/100 g/min, the values in gray matter structures of the posterior fossa were 25-30 mumol/100 g/min, the lowest LCMRGl was found in the white matter (15-20 mumol/100 g/min). During sensory stimulation by various modalities functional activation increases LCMRGl in the respective special areas, while sleep decreases metabolic rate in all cortical and basal gray matter structures. In many neurological disorders CMRGl is altered in a disease-specific pattern. In dementia of the Alzheimer type CMRGl is impaired even in early stages with accentuation in the parieto-temporal cortex, while in multi-infarct dementia glucose uptake is mainly reduced in the multifocal small infarcts. In Huntington's chorea the most conspicuous changes are found in the caudate nucleus and putamen. In cases of focal lesions (e.g. ischemic infarcts) metabolic disturbances extend far beyond the site of the primary lesion and inactivation of metabolism is found in intact brain structures far away from the anatomical lesion. Additional applications of PET include determination of the metabolism of various substrates, of protein synthesis, of function and distribution of receptors, of tumor growth and of the distribution of drugs as well as the measurement of oxygen consumption, blood flow and blood volume.

  14. Positron emission tomography in epilepsy

    International Nuclear Information System (INIS)

    Hosokawa, Shinichi; Kato, Motohiro; Otsuka, Makoto; Kuwabara, Yasuo; Ichiya, Yuichi; Goto, Ikuo

    1989-01-01

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

  15. Radiopharmaceutical chemistry for positron emission tomography

    NARCIS (Netherlands)

    Elsinga, PH

    Radiopharmaceutical chemistry includes the selection, preparation, and preclinical evaluation of radiolabeled compounds. This paper describes selection criteria for candidates for positron emission tomography (PET) investigations. Practical aspects of nucleophilic and electrophilic

  16. Positron emission tomography studies of brain receptors

    International Nuclear Information System (INIS)

    Maziere, B.; Maziere, M.

    1991-01-01

    Probing the regional distribution and affinity of receptors in the brain, in vivo, in human and non human primates has become possible with the use of selective ligands labelled with positron emitting radionuclides and positron emission tomography (PET). After describing the techniques used in positron emission tomography to characterize a ligand receptor binding and discussing the choice of the label and the limitations and complexities of the in vivo approach, the results obtained in the PET studies of various neurotransmission systems: dopaminergic, opiate, benzodiazepine, serotonin and cholinergic systems are reviewed

  17. New Possibilities of Positron-Emission Tomography

    Science.gov (United States)

    Volobuev, A. N.

    2018-01-01

    The reasons for the emergence of the angular distribution of photons generated as a result of annihilation of an electron and a positron in a positron-emission tomograph are investigated. It is shown that the angular distribution of the radiation intensity (i.e., the probability of photon emission at different angles) is a consequence of the Doppler effect in the center-of-mass reference system of the electron and the positron. In the reference frame attached to the electron, the angular distribution of the number of emitted photons does not exists but is replaced by the Doppler shift of the frequency of photons. The results obtained in this study make it possible to extend the potentialities of the positron-emission tomograph in the diagnostics of diseases and to obtain additional mechanical characteristics of human tissues, such as density and viscosity.

  18. Positron emission tomography with Positome, 2

    International Nuclear Information System (INIS)

    Nukui, Hideaki; Yamamoto, Y.L.; Thompson, C.J.; Feindel, W.

    1979-01-01

    Positron emission tomography with Positome II using 68 Ga-EDTA was performed in cases with brain tumor and cerebral arteriovenous malformation. A significant focal uptake in static study and hemodynamic changes in dynamic study were noted in all cases except one case with intracranial lipoma. Comparing this method with sup(99m) Tc-pertechnetate cerebral image study and computerized axial tomography, the diagnostic rate for detecting brain tumor was almost equal in all of these three methods. However, detecting and localizing was easier and clearer in static positron emission tomography with 68 Ga-EDTA than in sup(99m) Tc-pertechnetate cerebral image and computerized axial tomography without infusion of contrast medium. Furthermore, static positron emission tomography with 68 Ga-EDTA was superior to computerized axial tomography without infusion of contrast medium for detecting cerebral arteriovenous malformation. Concerning dynamic positron emission tomography with 68 Ga-EDTA, semiquantitative values obtained by this method correlated well with findings of computerized axial tomography and was thought to be more precise and in detail than the findings of sup(99m) Tc-pertechnetate cerebral image study. Summation of the previous studies about dynamic positron emission tomography with 77 Kr in occlusive cerebrovascular disease is also reported. In conclusion, static positron emission tomography with 68 Ga-EDTA is a very useful diagnostic method for detecting and localizing brain tumor and cerebral arteriovenous malformation without any attendant complications. Furthermore, a good combination of static and dynamic positron emission tomography and computerized axial tomography appear to be outstandingly effective for not only detecting the lesion but also understanding the pathophysiological aspect in cases with various intracranial lesions. (author)

  19. Positron-molecule interactions and corresponding positron attachment to molecules. As a basis for positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Tachikawa, Masanori; Kimura, Mineo; Pichl, Lukas

    2007-01-01

    Through positron and electron interactions, they annihilate emitting primarily two gamma rays with 180-degree opposite directions. Positron spectroscopy using the characteristics of these gamma rays has been employed for analyzing various properties of material as well as for positron emission tomography (PET). However, its fundamental physics of positron-electron interactions and resulting features of emitting gamma rays are not well understood. By obtaining better understanding of positron interactions, it should become possible to provide the firm bases for positron spectroscopy in finer accuracy and quality. Here, we propose a significant mechanism for positron annihilation through positron attachment process, which may help increase the quality of positron spectroscopy. (author)

  20. Emission features in the spectrum of NGC 7027 near 3. 3 microns at very high resolution

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, R.P.; Moorhead, J.M.; Wehlau, W.H.; Maillard, J.P. (Western Ontario Univ., London (Canada) CNRS, Institut d' Astrophysique, Paris (France))

    1991-02-01

    A very high resolution spectrum is presented of the planetary nebula NGC 7027 over a 200/cm interval centered at 2950/cm, and the features found are described: (1) nebular continuum, (2) atomic recombination lines of H and He II, and (3) three broader emission features of uncertain origin. For the latter the first evidence is presented that the 3.46 micron feature and possibly the 3.40 micron feature are resolvable into a sequence of narrower features. The interpretation of the broader features is discussed in terms of the hypothesis of identification with emission by polycyclic aromatic hydrocarbons. 18 refs.

  1. Positron emission tomography imaging of gene expression

    International Nuclear Information System (INIS)

    Tang Ganghua

    2001-01-01

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

  2. Ionization and positron emission in giant quasiatoms

    International Nuclear Information System (INIS)

    Soff, G.; Reinhardt, J.; Reus, T. de; Wietschorke, K.H.; Schaefer, A.; Mueller, B.; Greiner, W.; Mueller, U.; Schlueter, P.

    1985-07-01

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

  3. High resolution of black carbon and organic carbon emissions in the Pearl River Delta region, China.

    Science.gov (United States)

    Zheng, Junyu; He, Min; Shen, Xingling; Yin, Shasha; Yuan, Zibing

    2012-11-01

    A high-resolution regional black carbon (BC) and organic carbon (OC) emission inventory for the year 2009 was developed for the Pearl River Delta (PRD) region, China, based on the collected activity data and the latest emission factors. PM(2.5), BC and OC emissions were estimated to be 303 kt, 39 kt and 31 kt, respectively. Industrial processes were major contributing sources to PM(2.5) emissions. BC emissions were mainly from mobile sources, accounting for 65.0%, while 34.1% of OC emissions were from residential combustion. The primary OC/BC ratios for individual cities in the PRD region were dependent on the levels of economic development due to differences in source characteristics, with high ratios in the less developed cities and low ratios in the central and southern developed areas. The preliminary temporal profiles were established, showing the highest OC emissions in winter and relatively constant BC emissions throughout the year. The emissions were spatially allocated into grid cells with a resolution of 3 km × 3 km. Large amounts of BC emissions were distributed over the central-southern PRD city clusters, while OC emissions exhibited a relatively even spatial distribution due to the significant biomass burning emissions from the outlying area of the PRD region. Uncertainties in carbonaceous aerosol emissions were usually higher than in other primary pollutants like SO(2), NO(x), and PM(10). One of the key uncertainty sources was the emission factor, due to the absence of direct measurements of BC and OC emission rates. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Positron emission tomography in brain function study

    International Nuclear Information System (INIS)

    Wu Hua

    2006-01-01

    Little has been recognized about the advanced brain function. Recent years several new techniques such as event-related potentials, megnetoencephalography, functional magnetic resonance imaging and positron emission tomography (PET) have been used in the study of brain function. The methodology, application study in normal people and clinical patients of PET in brain function are reviewed. (authors)

  5. Positron emission tomography of the heart

    International Nuclear Information System (INIS)

    Budinger, T.F.; Yano, Y.; Moyer, B.R.; Mathis, C.A.; Ganz, E.; Huesman, R.H.; Derenzo, S.E.

    1982-01-01

    Positron emission tomography (PET) of the heart can measure blood perfusion, metabolism of fatty acids, metabolism of sugars, uptake of amino acids and can quantitate infarction volume. The principles which are basic to PET instrumentation and procedures for quantitative studies of the heart muscle with examples of measurements of myocardial flow and metabolism, are reviewed

  6. Positron emission tomography of the heart

    International Nuclear Information System (INIS)

    Budinger, T.F.; Yano, Y.; Huesman, R.H.; Derenzo, S.E.; Moyer, B.R.; Mathis, C.A.; Ganz, E.; Knittel, B.

    1983-01-01

    Positron emission tomography (PET) of the heart can measure blood perfusion, metabolism of fatty acids, metabolism of sugars, uptake of amino acids and can quantitate infarction volume. The principles are reviewed which are basic to PET instrumentation and procedures for quantitative studies of human physiology with examples of measurements of myocardial flow and metabolism

  7. Is positron emission tomography useful in stroke?

    NARCIS (Netherlands)

    DeReuck, J; Leys, D; DeKeyser, J

    Positron emission tomography (PET) has been widely used in the study of stroke and related cerebrovascular diseases. It has shown the various stages leading to cerebral infarction and defined the significance of the ischaemic penumbra. PET scan can predict the clinical outcome of patients with acute

  8. Positron emission tomography in malignant haematological disease

    NARCIS (Netherlands)

    Schot, Bartholomeus Wilhelmus

    2007-01-01

    Positron emission tomography (PET) is a diagnostic technique with a promising role especially in the haemato-oncology. Although its use in the management ; of malignant lymphoma seems to be established already, much about the true potential and drawbacks of FDG-PET in this disease are still unknown.

  9. Positron emission tomography applied to fluidization engineering

    NARCIS (Netherlands)

    Dechsiri, C; Ghione, A; van de Wiel, F; Dehling, HG; Paans, AMJ; Hoffmann, AC

    The movement of particles in a laboratory fluidized bed has been studied using Positron Emission Tomography (PET). With this non-invasive technique both pulses of various shapes and single tracer particles were followed in 3-D. The equipment and materials used made it possible to label actual bed

  10. Advanced Instrumentation for Positron Emission Tomography [PET

    Science.gov (United States)

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

    1985-04-01

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

  11. High-resolution forest carbon stocks and emissions in the Amazon.

    Science.gov (United States)

    Asner, Gregory P; Powell, George V N; Mascaro, Joseph; Knapp, David E; Clark, John K; Jacobson, James; Kennedy-Bowdoin, Ty; Balaji, Aravindh; Paez-Acosta, Guayana; Victoria, Eloy; Secada, Laura; Valqui, Michael; Hughes, R Flint

    2010-09-21

    Efforts to mitigate climate change through the Reduced Emissions from Deforestation and Degradation (REDD) depend on mapping and monitoring of tropical forest carbon stocks and emissions over large geographic areas. With a new integrated use of satellite imaging, airborne light detection and ranging, and field plots, we mapped aboveground carbon stocks and emissions at 0.1-ha resolution over 4.3 million ha of the Peruvian Amazon, an area twice that of all forests in Costa Rica, to reveal the determinants of forest carbon density and to demonstrate the feasibility of mapping carbon emissions for REDD. We discovered previously unknown variation in carbon storage at multiple scales based on geologic substrate and forest type. From 1999 to 2009, emissions from land use totaled 1.1% of the standing carbon throughout the region. Forest degradation, such as from selective logging, increased regional carbon emissions by 47% over deforestation alone, and secondary regrowth provided an 18% offset against total gross emissions. Very high-resolution monitoring reduces uncertainty in carbon emissions for REDD programs while uncovering fundamental environmental controls on forest carbon storage and their interactions with land-use change.

  12. High resolution krypton M/sub 4,5/ x-ray emission spectra

    International Nuclear Information System (INIS)

    Perera, R.C.C.; Hettrick, M.C.; Lindle, D.W.

    1987-10-01

    High resolution M/sub 4,5/ (3d → 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/ΔE, is about 300 in this energy range (∼80 eV). Three dipole-allowed 3d → 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr 2+ , and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab

  13. High-resolution spectroscopic search for the thermal emission of the extrasolar planet HD 217107 b

    OpenAIRE

    Cubillos, Patricio E.; Rojo, Patricio; Fortney, Jonathan J.

    2011-01-01

    We analyzed the combined near-infrared spectrum of a star-planet system with thermal emission atmospheric models, based on the composition and physical parameters of the system. The main objective of this work is to obtain the inclination of the orbit, the mass of the exoplanet, and the planet-to-star flux ratio. We present the results of our routines on the planetary system HD 217107, which was observed with the high-resolution spectrograph Phoenix at 2.14 microns. We revisited and tuned a c...

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

    International Nuclear Information System (INIS)

    Jacobson, H.G.

    1988-01-01

    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

  15. A New High-Resolution N2O Emission Inventory for China in 2008

    Science.gov (United States)

    Shang, Z.; Zhou, F.; Ciais, P.; Tao, S.; Piao, S.; Raymond, P. A.; He, C.; Li, B.; Wang, R.; Wang, X.; Peng, S.; Zeng, Z.; Chen, H.; Ying, N.; Hou, X.; Xu, P.

    2014-12-01

    The amount and geographic distribution of N2O emissions over China remain largely uncertain. Most of existing emission inventories use uniform emission factors (EFs) and the associated parameters and apply spatial proxies to downscale national or provincial data, resulting in the introduction of spatial bias. In this study, county-level and 0.1° × 0.1° gridded anthropogenic N2O emission inventories for China (PKU-N2O) in 2008 are developed based on high-resolution activity data and regional EFs and parameters. These new estimates are compared with estimates from EDGAR v4.2, GAINS-China, National Development and Reform Commission of China (NDRC), and with two sensitivity tests: one that uses high-resolution activity data but the default IPCC methodology (S1) and the other that uses regional EFs and parameters but starts from coarser-resolution activity data. The total N2O emissions are 2150 GgN2O/yr (interquartile range from 1174 to 2787 GgN2O/yr). Agriculture contributes 64% of the total, followed by energy (17%), indirect emissions (12%), wastes (5%), industry (2.8%), and wildfires (0.2%). Our national emission total is 17% greater than that of the EDGAR v4.2 global product sampled over China and is also greater than the GAINS-China, NDRC, and S1 estimates by 10%, 50%, and 17%, respectively. We also found that using uniform EFs and parameters or starting from national/provincial data causes systematic spatial biases compared to PKU-N2O. In addition, the considerable differences between the relative contributions of the six sectors across the six Agro-Climate Zones primarily reflect the different distributions of industrial activities and land use. Eastern China (8.7% area of China) is the largest contributor of N2O emissions and accounts for nearly 25% of the total. Spatial analysis also shows nonlinear relationships between N2O emission intensities and urbanization. Per-capita and per-GDP N2O emissions increase gradually with an increase in the urban

  16. Features and applications of positron emission tomography

    International Nuclear Information System (INIS)

    Fan Mingwu

    1997-01-01

    Positron emission tomography, the so-called world's smartest camera, is based on a NaI or BGO detector and imaging of positron-emitting radioisotopes which are introduced as a tracer into the regional tissue or organ of interest. With the aid of a computer visual images of a series of these distributions can be built into a picture of the functional status of the tissue or organ being imaged. This highly accurate imaging technique is already widely used for clinical diagnostics heart disease, brain disorder, tumors and so on

  17. Electrocardiographic gating in positron emission computed tomography

    International Nuclear Information System (INIS)

    Hoffman, E.J.; Phelps, M.E.; Wisenberg, G.; Schelbert, H.R.; Kuhl, D.E.

    1979-01-01

    Electrocardiographic (ECG) synchronized multiple gated data acquisition was employed with positron emission computed tomography (ECT) to obtain images of myocardial blood pool and myocardium. The feasibility and requirements of multiple gated data acquisition in positron ECT were investigated for 13NH3, ( 18 F)-2-fluoro-2-D-deoxyglucose, and ( 11 C)-carboxyhemoglobin. Examples are shown in which image detail is enhanced and image interpretation is facilitated when ECG gating is employed in the data collection. Analysis of count rate data from a series of volunteers indicates that multiple, statistically adequate images can be obtained under a multiple gated data collection format without an increase in administered dose

  18. Positron emission tomography of the lung

    International Nuclear Information System (INIS)

    Wollmer, P.

    1984-01-01

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

  19. High-resolution ammonia emissions inventories in Fujian, China, 2009-2015

    Science.gov (United States)

    Wu, Shui-Ping; Zhang, Yin-Ju; Schwab, James J.; Li, Yang-Fan; Liu, Yuan-Long; Yuan, Chung-Shin

    2017-08-01

    A high-resolution NH3 emission inventory was developed based on the corrected emission factors and county-level activity data. To provide model-ready emission input, the NH3 emission inventory was gridded for the modeling domain at 1 × 1 km resolution using source-based spatial surrogates and a GIS system. The best estimate of total NH3 emission for the province was 228.02 kt in 2015 with a percentage uncertainty of ±16.3%. Four major contributors were farmland ecosystem, livestock wastes, humans and waste treatment, which contributed 39.4%, 43.1%, 4.9%, and 4.2% of the total emissions, respectively. The averaged NH3 emission density for the whole region was 1.88 t km-2 yr-1 and the higher values were found in coastal areas with higher dense populations. The seasonal patterns, with higher emissions in summer, were consistent with the patterns of temperature and planting practices. From 2009 to 2015, annual NH3 emissions increased from 218.49 kt to 228.02 kt. All of these changes are insignificant compared to the estimated overall uncertainties in the analysis, but indicative of changes in the source categories over this period. Between 2009 and 2015, the largest changes occurred in human emissions and waste treatment plants, which were consistent with the process of rapid urbanization. Meanwhile, the decrease of emissions from pigs was slightly higher than the increased emissions from broilers and the increased emissions from meat goats and beef cattle due to the combine effects of increasingly stringent environmental requirements for pig farms and shift away from pork consumption to beef, chicken and mutton. The validity of the estimates was further evaluated using uncertainty analysis, comparison with previous studies, and correlation analysis between emission density and observed ground ammonia. The inventories reflect the changes in economic progress and environmental protection and can provide scientific basis for the establishment of effective PM2.5 control

  20. Positron emission tomography in movement disorders

    International Nuclear Information System (INIS)

    Martin, W.R.W.

    1985-01-01

    Positron emission tomography provides a method for the quantitation of regional function within the living human brain. Studies of cerebral metabolism and blood flow in patients with Huntington's disease, Parkinson's disease and focal dystonia have revealed functional abnormalities within substructures of the basal ganglia. Recent developments permit assessment of both pre-synaptic and post-synaptic function ion dopaminergic pathways. These techniques are now being applied to studies of movement disorders in human subjects

  1. Positron emission tomography in movement disorders

    Energy Technology Data Exchange (ETDEWEB)

    Martin, W R.W.

    1985-02-01

    Positron emission tomography provides a method for the quantitation of regional function within the living human brain. Studies of cerebral metabolism and blood flow in patients with Huntington's disease, Parkinson's disease and focal dystonia have revealed functional abnormalities within substructures of the basal ganglia. Recent developments permit assessment of both pre-synaptic and post-synaptic function in dopaminergic pathways. These techniques are now being applied to studies of movement disorders in human subjects.

  2. High-resolution mapping of biomass burning emissions in tropical regions across three continents

    Science.gov (United States)

    Shi, Yusheng; Matsunaga, Tsuneo; Saito, Makoto

    2015-04-01

    Biomass burning emissions from open vegetation fires (forest fires, savanna fires, agricultural waste burning), human waste and biofuel combustion contain large amounts of trace gases (e.g., CO2, CH4, and N2O) and aerosols (BC and OC), which significantly impact ecosystem productivity, global atmospheric chemistry, and climate . With the help of recently released satellite products, biomass density based on satellite and ground-based observation data, and spatial variable combustion factors, this study developed a new high-resolution emissions inventory for biomass burning in tropical regions across three continents in 2010. Emissions of trace gases and aerosols from open vegetation burning are estimated from burned areas, fuel loads, combustion factors, and emission factors. Burned areas were derived from MODIS MCD64A1 burned area product, fuel loads were mapped from biomass density data sets for herbaceous and tree-covered land based on satellite and ground-based observation data. To account for spatial heterogeneity in combustion factors, global fractional tree cover (MOD44B) and vegetation cover maps (MCD12Q1) were introduced to estimate the combustion factors in different regions by using their relationship with tree cover under less than 40%, between 40-60% and above 60% conditions. For emission factors, the average values for each fuel type from field measurements are used. In addition to biomass burning from open vegetation fires, the emissions from human waste (residential and dump) burning and biofuel burning in 2010 were also estimated for 76 countries in tropical regions across the three continents and then allocated into each pixel with 1 km grid based on the population density (Gridded Population of the World v3). Our total estimates for the tropical regions across the three continents in 2010 were 17744.5 Tg CO2, 730.3 Tg CO, 32.0 Tg CH4, 31.6 Tg NOx, 119.2 Tg NMOC, 6.3 Tg SO2, 9.8 NH3 Tg, 81.8 Tg PM2.5, 48.0 Tg OC, and 5.7 Tg BC, respectively. Open

  3. Positron emission tomography now and in the future

    International Nuclear Information System (INIS)

    Vaalburg, W.

    1987-01-01

    A survey is given of positron emission tomography used in nuclear medicine. The production of positron emitting radionuclides is discussed. The development of positron detectors is described. The application of positron emission tomography in cardiology, oncology and neurology is treated. The authors conclude that PET is a unique method to examine metabolic processes, although the method is still in its infancy. 7 refs.; 1 table

  4. High-resolution inversion of OMI formaldehyde columns over the Southeast US to infer isoprene emissions

    Science.gov (United States)

    Kaiser, J.; Zhu, L.; Travis, K.; Jacob, D.

    2017-12-01

    In the South East United States, biogenic isoprene fuels tropospheric ozone formation, and its oxidation products contribute significantly to organic aerosol. Bottom-up emission inventories rely on very limited isoprene emission and land-cover data, yielding uncertainties of a factor of 2 or more. Here, we use formaldehyde columns from the Ozone Monitoring Instrument in a high-resolution (0.25 x 0.325o) adjoint-based inversion to constrain isoprene emissions over the SE US during Aug-Sept of 2013. We find that the MEGANv2.1 inventory is biased high over most of the SE US. Our derived scaling factors show significant spatial variability, with the largest corrections applied to Louisiana and the Edwards Plateau in Texas. We test our inversion results against a comprehensive set of isoprene oxidation product observations from the NASA SEAC4RS flight campaign. The SEAC4RS data provides new confidence in the satellite retrievals and in mechanism linking isoprene oxidation to formaldehyde production. Finally, we relate the posterior scaling factors to the underlying land-type, and examine potential sources of observed biases.

  5. Extracting chemical information from high-resolution Kβ X-ray emission spectroscopy

    Science.gov (United States)

    Limandri, S.; Robledo, J.; Tirao, G.

    2018-06-01

    High-resolution X-ray emission spectroscopy allows studying the chemical environment of a wide variety of materials. Chemical information can be obtained by fitting the X-ray spectra and observing the behavior of some spectral features. Spectral changes can also be quantified by means of statistical parameters calculated by considering the spectrum as a probability distribution. Another possibility is to perform statistical multivariate analysis, such as principal component analysis. In this work the performance of these procedures for extracting chemical information in X-ray emission spectroscopy spectra for mixtures of Mn2+ and Mn4+ oxides are studied. A detail analysis of the parameters obtained, as well as the associated uncertainties is shown. The methodologies are also applied for Mn oxidation state characterization of double perovskite oxides Ba1+xLa1-xMnSbO6 (with 0 ≤ x ≤ 0.7). The results show that statistical parameters and multivariate analysis are the most suitable for the analysis of this kind of spectra.

  6. In-situ positron emission of CO oxidation

    NARCIS (Netherlands)

    Vonkeman, K.A.; Jonkers, G.; Wal, van der S.W.A.; Santen, van R.A.

    1993-01-01

    Using a Neuro ECAT positron tomog., the Positron Emission computed Tomog. (PET) was utilized to image the catalytic oxidn. of CO by using CO and CO2, labeled with short lived positron emitting nuclides. Studies were performed over highly dispersed CeO2/g-Al2O3 supported Pt and Rh catalysts. With a

  7. Positron emission tomography of FDG in schizophrenia

    International Nuclear Information System (INIS)

    Sargent, T. III; Kusubov, N.

    1986-01-01

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

  8. Positron Emission Tomography: Its 65 years

    International Nuclear Information System (INIS)

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

    2016-01-01

    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, preclinical and hybrid scanners (i.e., PET/CT and PET/MR) is reported. Finally the actual trend and the recent and future technological developments are fully illustrated.

  9. Methods and instrumentation for positron emission tomography

    International Nuclear Information System (INIS)

    Mandelkern, M.A.; Phelps, M.E.

    1988-01-01

    This paper reports on positron emission tomography (PET), a technique for the noninvasive measurement of local tissue concentrations of injected radioactive tracers. Tracer kinetics techniques can be applied to this information to quantify physiologic function in human tissue. In the tracer method, a pharmaceutical is labeled by a radioactive atom. When introduced into the subject that molecule follows a physiologic pathway. The space- and time-dependent distribution of the radionuclide is obtained via an imaging technique. If the radiopharmaceutical is sufficiently analogous to a natural substrate or other substance of interest, a quantitative image can be translated into a physiologic measurement

  10. Contribution of positron emission tomography in neurology

    International Nuclear Information System (INIS)

    Salmon, E.; Franck, G.

    1992-01-01

    Positron Emission Tomography (PET) is a scanner technique using tracers labelled with shortlived radioisotopes which allows to study and quantify human metabolic processes or drug pharmacology in vivo. The technique is first applied in physiological studies. Sleep, normal brain metabolism or cerebral activations have been studied. The pharmacological approach concerns both drug distribution in the human brain and blood flow or metabolic variations under treatment. Main neurological applications in pathology are cerebrovascular disorders, diseases leading to dementia, epilepsy, movement disorders, and brain tumors. In each field of application, PET gives unique and frequently early informations. It nicely combines both dynamic informations and measurement precision. (author)

  11. High-resolution positron Q-value measurements and nuclear-structure studies far from the stability line. Progress report

    International Nuclear Information System (INIS)

    Avignone, F.T. III.

    1981-01-01

    Extensive data analysis and theoretical analysis has been done to complete the extensive decay scheme investigation of 206 208 Fr and the level structures of 206 208 Rn. A final version of a journal article is presented in preprint form. Extensive Monte Carlo calculations have been made to correct the end point energies of positron spectra taken with intrinsic Ge detectors for annihilation radiation interferences. These calculations were tested using the decay of 82 Sr which has previously measured positron branches. This technique was applied to the positron spectra collected at the on-line UNISOR isotope separator. The reactions used were 60 Ni( 20 Ne;p2n) 77 Rb and 60 Ni( 20 Ne;pn) 78 Rb. Values for 5, γ-β + coincidence positron end point energies are given for the decay of 77 Rb. The implied Q-value is 5.075 +- 0.010 MeV. A complete paper on the calculated corrections is presented. A flow chart of a more complete program which accounts for positrons scattering out of the detector and for bremsstralung radiation is also presented. End-point energies of four β + branches in 77 Rb are given as well as a proposed energy level scheme of 75 Kr based on γ-γ coincidence data taken at UNISOR

  12. High resolution measurements and modeling of auroral hydrogen emission line profiles

    Directory of Open Access Journals (Sweden)

    B. S. Lanchester

    Full Text Available Measurements in the visible wavelength range at high spectral resolution (1.3 Å have been made at Longyearbyen, Svalbard (15.8 E,78.2 N during an interval of intense proton precipitation. The shape and Doppler shift of hydrogen Balmer beta line profiles have been compared with model line profiles, using as input ion energy spectra from almost coincident passes of the FAST and DMSP spacecraft. The comparison shows that the simulation contains the important physical processes that produce the profiles, and confirms that measured changes in the shape and peak wave-length of the hydrogen profiles are the result of changing energy input. This combination of high resolution measurements with modeling provides a method of estimating the incoming energy and changes in flux of precipitating protons over Svalbard, for given energy and pitch-angle distributions. Whereas for electron precipitation, information on the incident particles is derived from brightness and brightness ratios which require at least two spectral windows, for proton precipitation the Doppler profile of resulting hydrogen emission is directly related to the energy and energy flux of the incident energetic protons and can be used to gather information about the source region. As well as the expected Doppler shift to shorter wavelengths, the measured profiles have a significant red-shifted component, the result of upward flowing emitting hydrogen atoms.

    Key words. Ionosphere (auroral ionosphere; particle precipitation – Magnetospheric physics (auroral phenomena

  13. High resolution measurements and modeling of auroral hydrogen emission line profiles

    Directory of Open Access Journals (Sweden)

    B. S. Lanchester

    2003-07-01

    Full Text Available Measurements in the visible wavelength range at high spectral resolution (1.3 Å have been made at Longyearbyen, Svalbard (15.8 E,78.2 N during an interval of intense proton precipitation. The shape and Doppler shift of hydrogen Balmer beta line profiles have been compared with model line profiles, using as input ion energy spectra from almost coincident passes of the FAST and DMSP spacecraft. The comparison shows that the simulation contains the important physical processes that produce the profiles, and confirms that measured changes in the shape and peak wave-length of the hydrogen profiles are the result of changing energy input. This combination of high resolution measurements with modeling provides a method of estimating the incoming energy and changes in flux of precipitating protons over Svalbard, for given energy and pitch-angle distributions. Whereas for electron precipitation, information on the incident particles is derived from brightness and brightness ratios which require at least two spectral windows, for proton precipitation the Doppler profile of resulting hydrogen emission is directly related to the energy and energy flux of the incident energetic protons and can be used to gather information about the source region. As well as the expected Doppler shift to shorter wavelengths, the measured profiles have a significant red-shifted component, the result of upward flowing emitting hydrogen atoms.Key words. Ionosphere (auroral ionosphere; particle precipitation – Magnetospheric physics (auroral phenomena

  14. High-Resolution Spectroscopic Observations of Potassium Emissions in the Lunar Exosphere

    Science.gov (United States)

    Robertson, Sarena D.; Oliversen, Ronald J.; Mierkiewicz, Edwin J.; Kuruppuaratchi, Dona Chathuni P.; Derr, Nicholas James; Gallant, Margaret A.; McFarland, Christina G.; Sarantos, Menelaos

    2018-01-01

    We investigate lunar exospheric potassium D1 emissions (7698.9646 Å) using high-resolution (R = 180,000 or 1.7 km/s) spectroscopy with our dual-etalon Fabry-Perot instrument to measure line widths and radial velocities. The Field of View (FOV) is 2 arcmins (~224 km at the mean lunar distance of 384,400 km) positioned tangent to the sunlit limb. The FOV placements are at cardinal directions from a variety of reference craters. All observations are collected at the National Solar Observatory McMath-Pierce Telescope in Kitt Peak, Arizona. The data are from several observations from 2014 through 2017 at various times of the year. Results are produced via a newly created automated data reduction using Python. Python was chosen as an open-source alternative to the previously used IDL and MATLAB scripts to decrease the cost of software licenses and maintenance. The potassium spectral line profiles provide a direct method to track exospheric effective temperatures and velocities. By monitoring the state of the potassium emissions over different lunar phases, solar activity, and the influx of meteor streams, we can constrain physical processes of sources and sinks at the lunar surface. Mechanisms that create the exosphere include photon-stimulated desorption, thermal evaporation, meteoroid impact vaporization, and ion sputtering via solar wind. In contrast, the exosphere is diminished due to the low lunar escape velocity, solar radiation pressure, and neutral gas being ionized and swept away by the interplanetary and terrestrial magnetic field. Preliminary analysis of 2017 data (January through June, excluding February) indicates an average potassium temperature of 1140 K but varying over the range of 550 K to 2000 K. Preliminary results from 2014 data depict a similar range of temperatures to that of 2017. Further analysis is expected for additional data from 2014 to later observations in 2017 that were not included in the initial set of models.

  15. High resolution X-ray emission spectroscopy: An advanced tool for actinide research

    Science.gov (United States)

    Vitova, T.; Brendebach, B.; Dardenne, K.; Denecke, M. A.; Lebid, A.; Löble, M.; Rothe, J.; Batuk, O. N.; Hormes, J.; Liu, D.; Breher, F.; Geckeis, H.

    2010-03-01

    High resolution X-ray emission spectroscopy (HRXES) is becoming increasingly important for our understanding of electronic and coordination structures. The combination of such information with development of quantum theoretical tools will advance our capability for predicting reactivity and physical behavior especially of 5f elements. HRXES can be used to remove lifetime broadening by registering the partial fluorescence yield emitted by the sample (i.e., recording a windowed signal from the energy dispersed fluorescence emission while varying incident photon energy), thereby yielding highly resolved X-ray absorption fine structure (XAFS) spectra. Such spectra often display resonant features not observed in conventional XAFS. The spectrometer set-up can also be used for a wide range of other experiments, for example, resonant inelastic X-ray scattering (RIXS), where bulk electron configuration information in solids, liquids and gases is obtained. Valence-selective XAFS studies, where the local structure of a selected element's valence state present in a mixture of valence states can be obtained, as well as site-selective XAFS studies, where the coordination structure of a metal bound to selected elements can be differentiated from that of all the other ligating atoms. A HRXES spectrometer has been constructed and is presently being commissioned for use at the INE-Beamline for actinide research at the synchrotron source ANKA at FZK. We present the spectrometer's compact, modular design, optimized for attaining a wide range of energies, and first test measurement results. Examples from HRXES studies of lanthanides, actinides counter parts, are also shown.

  16. Positron emission tomography tracers for imaging angiogenesis

    International Nuclear Information System (INIS)

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

    2010-01-01

    Position emission tomography imaging of angiogenesis may provide non-invasive insights into the corresponding molecular processes and may be applied for individualized treatment planning of antiangiogenic therapies. At the moment, most strategies are focusing on the development of radiolabelled proteins and antibody formats targeting VEGF and its receptor or the ED-B domain of a fibronectin isoform as well as radiolabelled matrix metalloproteinase inhibitors or α v β 3 integrin antagonists. Great efforts are being made to develop suitable tracers for different target structures. All of the major strategies focusing on the development of radiolabelled compounds for use with positron emission tomography are summarized in this review. However, because the most intensive work is concentrated on the development of radiolabelled RGD peptides for imaging α v β 3 expression, which has successfully made its way from bench to bedside, these developments are especially emphasized. (orig.)

  17. Fluorinated tracers for imaging cancer with positron emission tomography

    International Nuclear Information System (INIS)

    Couturier, Olivier; Chatal, Jean-Francois; Luxen, Andre; Vuillez, Jean-Philippe; Rigo, Pierre; Hustinx, Roland

    2004-01-01

    2-[ 18 F]fluoro-2-deoxy-d-glucose (FDG) is currently the only fluorinated tracer used in routine clinical positron emission tomography (PET). Fluorine-18 is considered the ideal radioisotope for PET imaging owing to the low positron energy (0.64 MeV), which not only limits the dose rate to the patient but also results in a relatively short range of emission in tissue, thereby providing high-resolution images. Further, the 110-min physical half-life allows for high-yield radiosynthesis, transport from the production site to the imaging site and imaging protocols that may span hours, which permits dynamic studies and assessment of potentially fairly slow metabolic processes. The synthesis of fluorinated tracers as an alternative to FDG was initially tested using nucleophilic fluorination of the molecule, as performed when radiolabelling with iodine-124 or bromide-76. However, in addition to being long, with multiple steps, this procedure is not recommended for bioactive molecules containing reactive groups such as amine or thiol groups. Radiochemical yields are also often low. More recently, radiosynthesis from prosthetic group precursors, which allows easier radiolabelling of biomolecules, has led to the development of numerous fluorinated tracers. Given the wide availability of 18 F, such tracers may well develop into important routine tracers. This article is a review of the literature concerning fluorinated radiotracers recently developed and under investigation for possible PET imaging in cancer patients. Two groups can be distinguished. The first includes ''generalist'' tracers, i.e. tracers amenable to use in a wide variety of tumours and indications, very similar in this respect to FDG. These are tracers for non-specific cell metabolism, such as protein synthesis, amino acid transport, nucleic acid synthesis or membrane component synthesis. The second group consists of ''specific'' tracers for receptor expression (i.e. oestrogens or somatostatin), cell

  18. High resolution positron Q-value measurements and nuclear structure studies far from the stability line. Progress report

    International Nuclear Information System (INIS)

    Avignone, F.T. III.

    1982-01-01

    Research progress in briefly described, and details are presented in the attached preprints and reprints: (1) precision mass differences in light rubidium and krypton isotopes utilizing beta endpoint measurements; (2) precision mass measurements utilizing beta endpoints; (3) Monte Carlo calculations predicting the response of intrinsic GE detectors to electrons and positrons; and (4) reactor antineutrino spectra and nuclear spectroscopy of isotopes far from beta stability

  19. Efficient high-resolution X-ray emission spectrometry using synchrotron radiation

    International Nuclear Information System (INIS)

    Unterumsberger, Rainer

    2015-01-01

    The aim of the present work is to get access to high-resolution X-Ray Emission Spectrometry (XES) at nanoscaled materials, consisting of light elements and transition metals, by the increase of the sensitivity of a Wavelength-Dispersive Spectrometer (WDS) in the soft X-Ray range. The increase of the sensitivity was achieved by a refocusing of the incident radiation. With the increased sensitivity of the WDS, it was possible to determine the chemical species of different, nominal 100 nm thin titanium oxides. The combination of the refocusing optic and calibrated spectrometer enabled the detection and deconvolution of the L-fluorescence radiation of these nanoscaled titanium oxides. Due to the calibration of the spectrometer, a reliable determination of the transition probabilities of the titanium La- and Ll-fluorescence lines as a function of the chemical state is possible. To the best of my knowledge, the determination of the transition probabilities as a function of the chemical state in the soft X-Ray range has not been investigated yet. The quality of the refocusing was characterized using different diagnostic tools. Vertical full width at half maximum (FWHM) values of the focused beam between 10 μm to 20 μm and horizontal FWHM values between 12 μm and 25 μm could be achieved over an energy range of 180 eV to 1310 eV. Using calibrated photodiodes, it was possible to determine the absolute transmission of the used single bounce monocapillary as well as to monitor the absolute photon flux. By means of the refocusing, it was possible to increase the photon flux by a factor of 4.9 experimentally. The increase of the photon flux enables the analysis of nanoscaled materials with the used spectrometer. This could be shown based on the determination of the lower limit of detection of boron Ka and titanium La. In both cases, the lower limit of detection of 0.4 nm equivalent layer thickness was achieved (about 1.10 -7 g/cm 2 to 2.10 -7 g/cm 2 or 3.10 15 atoms/cm 2 to

  20. High-resolution atmospheric emission inventory of the argentine energy sector. Comparison with edgar global emission database

    Directory of Open Access Journals (Sweden)

    S. Enrique Puliafito

    2017-12-01

    Full Text Available This study presents a 2014 high-resolution spatially disaggregated emission inventory (0.025° × 0.025° horizontal resolution, of the main activities in the energy sector in Argentina. The sub-sectors considered are public generation of electricity, oil refineries, cement production, transport (maritime, air, rail and road, residential and commercial. The following pollutants were included: greenhouse gases (CO2, CH4, N2O, ozone precursors (CO, NOx, VOC and other specific air quality indicators such as SO2, PM10, and PM2.5. This work could contribute to a better geographical allocation of the pollutant sources through census based population maps. Considering the sources of greenhouse gas emissions, the total amount is 144 Tg CO2eq, from which the transportation sector emits 57.8 Tg (40%; followed by electricity generation, with 40.9 Tg (28%; residential + commercial, with 31.24 Tg (22%; and cement and refinery production, with 14.3 Tg (10%. This inventory shows that 49% of the total emissions occur in rural areas: 31% in rural areas of medium population density, 13% in intermediate urban areas and 7% in densely populated urban areas. However, if emissions are analyzed by extension (per square km, the largest impact is observed in medium and densely populated urban areas, reaching more than 20.3 Gg per square km of greenhouse gases, 297 Mg/km2 of ozone precursors gases and 11.5 Mg/km2 of other air quality emissions. A comparison with the EDGAR global emission database shows that, although the total country emissions are similar for several sub sectors and pollutants, its spatial distribution is not applicable to Argentina. The road and residential transport emissions represented by EDGAR result in an overestimation of emissions in rural areas and an underestimation in urban areas, especially in more densely populated areas. EDGAR underestimates 60 Gg of methane emissions from road transport sector and fugitive emissions from refining

  1. F-18-fluorodeoxyglucose-positron emission tomography in colorectal cancer

    International Nuclear Information System (INIS)

    Joerg, L.; Langsteger, W.

    2002-01-01

    Whole-body positron emission tomography (PET) with the radiolabeled glucose analog F-18-fluorodeoxyglucose (F-18-FDG) is a sensitive diagnostic tool that images tumors based on increased uptake of glucose. Several recent publications have shown that F-18-fluorodeoxyglucose-positron emission tomography is more sensitive than computed-tomography (CT) in detecting colorectal cancer. In patients with increasing CEA (carcinoembryonic antigen) and no evidence of recurrent disease on CT F-18-fluorodeoxyglucose-positron emission tomography often detects recurrent cancer. In all, patient management seems to be changed in about 25 % of patients who undergo F-18-fluorodeoxyglucose-positron emission tomography in addition to standard staging procedure. Limited reports to date on both chemotherapy and radiotherapy support the role of F-18-fluorodeoxyglucose-positron emission tomography in assessing treatment response. Also regarding preoperative staging of primary colorectal cancer the literature is very limited. (author)

  2. The Positron Emission Tomography. A diagnostic technique

    International Nuclear Information System (INIS)

    Salvadori, P.

    2001-01-01

    Positron Emission Tomography (PET) is a new imaging modality, which is able to assess non-invasively the biochemical mechanisms, underlying physiological and pathophysiological processes in vivo in humans. The technique relies on the administration of radioactive tracers labeled with short-lived positron emitters, which need to be produced on site via a particle accelerator (cyclotron). Radionuclides are produced upon request and formulated into biologically active organic molecules having precise pharmacokinetics and specificity. The radiotracer can be detected by the PET scanner and represented as tomographic sections (images of body sections) showing its regional distribution and concentration. This makes it possible to address clinical questions concerning occurrence and evolution of many diseases as well as their response to therapy. The ability to image (measure) biological processes and not only anatomy enables PET to explore diseases in the very early stage, including those diseases which are not related to modifications of organ structure (e.g. psychiatric diseases, metabolic disorders, biochemical disfunction). PET plays a major role, in conjunction with the other imaging modalities, to improve diagnosis capabilities and disease mechanism understanding [it

  3. Positron emission tomography (PET) in psychiatry

    International Nuclear Information System (INIS)

    Buchsbaum, M.S.

    1984-01-01

    In the past the approach to the brain has been necessarily indirect, employing peripheral fluids to assess central and regional neurochemical processes. Blood, urine, skin and muscle biopsy, and cerebrospinal fluid are valuable reflectors of the neurochemical and neuropharmacological activity of the brain, but are removed in time and place from disordered thought processes and diluted by the products of both functional and dysfunctional brain systems. Biopsy studies have helped in studying the functional disorders of organs like the liver, but they are destructive to the brain and less useful because unlike these organs, the brain has a regional variation in its chemistry. The experimental insights from animal studies focusing on the pharmacology of individual cell groups - in striatum or locus coeruleus, for example - cannot easily or unambigiously be applied to clinical populations. Positron emission tomography (PET) is a versatile approach utilizing the mathematics of x-ray transmission scanning (CT scanning) to produce slice images of radioisotope distribution. PET makes possible a wide range of metabolic studies. Positron emitters such as carbon-11 or fluorine-18 can be used to label glucose, amino acids, drugs, neurotransmitter precursors, and many other molecules and examine their distribution and fate in discrete cell groups

  4. Positron emission tomography of the heart

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-01-01

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

  5. Positron emission tomography in drug development

    International Nuclear Information System (INIS)

    Rubin, R. H.; Fischman, A. J.

    1997-01-01

    There are four kinds of measurements that can be carried out with positron emission tomography (PET) that can contribute significantly to the process of drug development: pharmacodynamic measurement of tissue metabolism influenced by a given drug; precise measurements of tissue blood flow; tissue pharmacokinetics of a given drug following administration of a particular dose; and the temporal course of ligand-receptor interaction. One or more of these measurements can greatly improve the decision making involved in determining the appropriate dose of a drug, the clinical situations in which a drug might be useful, and the linkage of pharmacokinetics with pharmacodynamics, which is at the heart of effective drug development. The greater the potential of a particular compound as a therapeutic agent, the greater the potential for PET to contribute to the drug development process

  6. Positron emission tomography of the heart

    International Nuclear Information System (INIS)

    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

  7. Applications of positron emission tomography to psychiatry

    International Nuclear Information System (INIS)

    Volkow, N.D.; Brodie, J.D.; Gomez-mont, F.

    1985-01-01

    The brain's inaccessibility has hampered investigation of the metabolic changes underlying the behavioral and psychological symptoms of psychiatric patients. Using positron emission transaxial tomography (PET) to study the functioning human brain opens the possibility of directly investigating the patterns of activity associated with mental illness. A major focus of present-day research in psychiatry has been to identify etiological agents that fit a medical model of psychiatric illness. Experiments seeking pathophysiological indices that would permit objective classification of psychiatric illnesses have failed to reveal consistent abnormalities. The lack of consistency is explained in part by research designs that deal with the brain as if it were a homogeneous organ. PET offers a unique technique for monitoring the regional biochemical activity that is associated with the different ''brain states'' and ''brain traits'' of normal subjects and psychiatric patients

  8. Motion correction in thoracic positron emission tomography

    CERN Document Server

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

    2015-01-01

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

  9. Positron emission tomography and basal ganglia functions

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Motohiro; Otsuka, Makoto; Taniwaki, Koukyo; Hosokawa, Shinichi; Kuwabara, Yasuo; Ichiya, Yuichi [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1990-05-01

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

  10. Instrumentation optimization for positron emission mammography

    International Nuclear Information System (INIS)

    Moses, William W.; Qi, Jinyi

    2003-01-01

    The past several years have seen designs for PET cameras optimized to image the breast, commonly known as Positron Emission Mammography or PEM cameras. The guiding principal behind PEM instrumentation is that a camera whose field of view is restricted to a single breast has higher performance and lower cost than a conventional PET camera. The most common geometry is a pair of parallel planes of detector modules, although geometries that encircle the breast have also been proposed. The ability of the detector modules to measure the depth of interaction (DOI) is also a relevant feature. This paper finds that while both the additional solid angle coverage afforded by encircling the breast and the decreased blurring afforded by the DOI measurement improve performance, the ability to measure DOI is more important than the ability to encircle the breast

  11. Positron emission tomography and basal ganglia functions

    International Nuclear Information System (INIS)

    Kato, Motohiro; Otsuka, Makoto; Taniwaki, Koukyo; Hosokawa, Shinichi; Kuwabara, Yasuo; Ichiya, Yuichi

    1990-01-01

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

  12. Fundamental limits of positron emission mammography

    International Nuclear Information System (INIS)

    Moses, William W.; Qi, Jinyi

    2001-01-01

    We explore the causes of performance limitation in positron emission mammography cameras. We compare two basic camera geometries containing the same volume of 511 keV photon detectors, one with a parallel plane geometry and another with a rectangular geometry. We find that both geometries have similar performance for the phantom imaged (in Monte Carlo simulation), even though the solid angle coverage of the rectangular camera is about 50 percent higher than the parallel plane camera. The reconstruction algorithm used significantly affects the resulting image; iterative methods significantly outperform the commonly used focal plane tomography. Finally, the characteristics of the tumor itself, specifically the absolute amount of radiotracer taken up by the tumor, will significantly affect the imaging performance

  13. Application of mathematical removal of positron range blurring in positron emission tomography

    International Nuclear Information System (INIS)

    Haber, S.F.; Derenzo, S.E.; Uber, D.

    1990-01-01

    The range of positrons in tissue is an important limitation to the ultimate spatial resolution achievable in positron emission tomography. In this work the authors have applied a Fourier deconvolution technique to remove range blurring in images taken by the Donner 600-crystal positron tomograph. Using phantom data, the authors have found significant improvement in the image quality and the FWHM for both 68 Ga and 82 Rb. These were successfully corrected so that the images and FWHM almost matched those of 18 F which has negligible positron range. However, statistical noise was increased by the deconvolution process and it was not practical to recover the full spatial resolution of the tomograph

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

    International Nuclear Information System (INIS)

    Sureau, F.

    2008-06-01

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

  15. Simultaneous in vivo positron emission tomography and magnetic resonance imaging.

    Science.gov (United States)

    Catana, Ciprian; Procissi, Daniel; Wu, Yibao; Judenhofer, Martin S; Qi, Jinyi; Pichler, Bernd J; Jacobs, Russell E; Cherry, Simon R

    2008-03-11

    Positron emission tomography (PET) and magnetic resonance imaging (MRI) are widely used in vivo imaging technologies with both clinical and biomedical research applications. The strengths of MRI include high-resolution, high-contrast morphologic imaging of soft tissues; the ability to image physiologic parameters such as diffusion and changes in oxygenation level resulting from neuronal stimulation; and the measurement of metabolites using chemical shift imaging. PET images the distribution of biologically targeted radiotracers with high sensitivity, but images generally lack anatomic context and are of lower spatial resolution. Integration of these technologies permits the acquisition of temporally correlated data showing the distribution of PET radiotracers and MRI contrast agents or MR-detectable metabolites, with registration to the underlying anatomy. An MRI-compatible PET scanner has been built for biomedical research applications that allows data from both modalities to be acquired simultaneously. Experiments demonstrate no effect of the MRI system on the spatial resolution of the PET system and <10% reduction in the fraction of radioactive decay events detected by the PET scanner inside the MRI. The signal-to-noise ratio and uniformity of the MR images, with the exception of one particular pulse sequence, were little affected by the presence of the PET scanner. In vivo simultaneous PET and MRI studies were performed in mice. Proof-of-principle in vivo MR spectroscopy and functional MRI experiments were also demonstrated with the combined scanner.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nestle, Ursula; Hentschel, Michael; Grosu, Anca-Ligia [Departments of Radiation Oncology, University of Freiburg, Robert Koch Str. 3, 79106 Freiburg (Germany); Weber, Wolfgang [Nuclear Medicine, University of Freiburg, Robert Koch Str. 3, 79106 Freiburg (Germany)], E-mail: ursula.nestle@uniklinik-freiburg.de

    2009-01-07

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

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

    Science.gov (United States)

    Nestle, Ursula; Weber, Wolfgang; Hentschel, Michael; Grosu, Anca-Ligia

    2009-01-07

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

  18. Cardiological applications of positron emission tomography

    International Nuclear Information System (INIS)

    Schelbert, H.; Czernin, J.

    1994-01-01

    Positron emission tomography (PET) expands the diagnostic possibilities of nuclear medicine techniques for the diagnosis of coronary artery disease and, especially, for the identification of myocardial viability. The presence of coronary artery disease can be detected by evaluation of myocardial blood flow at rest and during pharmacologically induced hyperemia with a sensitivity of 84 to 98% and a specificity of 78 to 100% according to recent studies. Comparative investigations in the same patients have demonstrated a significant gain in the diagnostic accuracy of PET as compared with single photon emission computed tomography (SPECT). PET has influenced even more profoundly the identification of myocardial viability. Measured against the functional outcome of regional contractile function after successful revascularization, an increase of glucose utilization relative to regional myocardial blood flow is 77 to 85% accurate in identifying reversibly injured myocardium. Conversely, PET is 78 to 92% accurate in identifying myocardium as irreversibly injured when pre-operative glucose uptake was reduced or absent. Recent studies have indicated that it is possible to predict to some extent post-revascularization improvement in left ventricular function as well as in congestive heart failure related symptoms in patients with ischemic cardiomyopathy. Furthermore, PET can identify patients with an increased risk of mortality and morbidity as a result of ischemic heart disease and, thus, stratify patients to the most appropriate and cost-effective therapeutic approach. (authors)

  19. Simultaneous emission and transmission scanning in positron emission tomography

    International Nuclear Information System (INIS)

    Satoh, Tomohiko; Tanaka, Kazumi; Kitamura, Keishi; Amano, Masaharu; Miura, Shuichi

    2001-01-01

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

  20. Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO2 emissions

    Directory of Open Access Journals (Sweden)

    S. Feng

    2016-07-01

    Full Text Available Megacities are major sources of anthropogenic fossil fuel CO2 (FFCO2 emissions. The spatial extents of these large urban systems cover areas of 10 000 km2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO2 emissions over the Los Angeles (LA megacity area. The Weather Research and Forecasting (WRF-Chem model was coupled to a very high-resolution FFCO2 emission product, Hestia-LA, to simulate atmospheric CO2 concentrations across the LA megacity at spatial resolutions as fine as  ∼  1 km. We evaluated multiple WRF configurations, selecting one that minimized errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010. Our results show no significant difference between moderate-resolution (4 km and high-resolution (1.3 km simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution and Hestia-LA (1.3 km resolution fossil fuel CO2 emission products to evaluate the impact of the spatial resolution of the CO2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO2 concentrations. We find that high spatial resolution in the fossil fuel CO2 emissions is more important than in the atmospheric model to capture CO2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO2 fields reflect the coverage of

  1. Positron emission tomography in drug development and drug evaluation

    NARCIS (Netherlands)

    Paans, AMJ; Vaalburg, W

    2000-01-01

    Positron Emission Tomography (PET) is an imaging modality which can determine biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labeled with positron emitting radionuclides as C-11, N-13, O-15 and F-18 and by measuring the annihilation radiation

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

  4. Amorphous silicon detectors in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-12-01

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

  5. Positron emission particle tracking in pulsatile flow

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Nitant; Ruggles, Arthur [University of Tennessee-Knoxville, Department of Nuclear Engineering, Knoxville, TN (United States); Wiggins, Cody [University of Tennessee-Knoxville, Department of Physics and Astronomy, Knoxville, TN (United States)

    2017-05-15

    Positron emission particle tracking (PEPT) is increasingly used to understand the flow characteristics in complex systems. This research utilizes PEPT to measure pulsatile flow of frequency 2.1 Hz in an elastic Masterkleer PVC tube of 19 mm inner diameter and 3.2 mm wall thickness. Anion exchange resin beads are labeled with {sup 18}F and delivered to a pump driven flow loop with motorized ball valve used to develop the pulsatile flow. Data are collected in the tube with circular cross section, and measurements are also collected with a section of the tube pinched. Nominal flow velocities are near 1 m/s and Reynolds numbers near 20,000. Many thousand PEPT particle traces are collected and synchronized with the flow pulsation. These Lagrangian data are presented as a series of 20 still frames depicting the 3-D velocity field present during each phase of the flow pulsation. Pressure data are also collected to resolve the pressure wave front moving through the open elastic tube at velocity 15.2 m/s. (orig.)

  6. Functional cardiac imaging: positron emission tomography

    International Nuclear Information System (INIS)

    Mullani, N.A.; Gould, K.L.

    1984-01-01

    Dynamic cardiovascular imaging plays a vital role in the diagnosis and treatment of cardiac disease by providing information about the function of the heart. During the past 30 years, cardiovascular imaging has evolved from the simple chest x-ray and fluoroscopy to such sophisticated techniques as invasive cardiac angiography and cinearteriography and, more recently, to noninvasive cardiac CT scanning, nuclear magnetic resonance, and positron emission tomography, which reflect more complex physiologic functions. As research tools, CT, NMR, and PET provide quantitative information on global as well as regional ventricular function, coronary artery stenosis, myocardial perfusion, glucose and fatty acid metabolism, or oxygen utilization, with little discomfort or risk to the patient. As imaging modalities become more sophisticated and more oriented toward clinical application, the prospect of routinely obtaining such functional information about the heart is becoming realistic. However, these advances are double-edged in that the interpretation of functional data is more complex than that of the anatomic imaging familiar to most physicians. They will require an enhanced understanding of the physiologic and biochemical processes, as well as of the instrumentation and techniques for analyzing the data. Of the new imaging modalities that provide functional information about the heart, PET is the most useful because it quantitates the regional distribution of radionuclides in vivo. Clinical applications, interpretation of data, and the impact of PET on our understanding of cardiac pathophysiology are discussed. 5 figures

  7. Amorphous silicon detectors in positron emission tomography

    International Nuclear Information System (INIS)

    Conti, M.; 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 ε 2 τ'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

  8. Positron emission tomography for the assessment of myocardial viability

    International Nuclear Information System (INIS)

    Schelbert, H.R.

    1991-01-01

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

  9. Simulation of the annihilation emission of galactic positrons

    International Nuclear Information System (INIS)

    Gillard, W.

    2008-01-01

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

  10. Emission features in the spectrum of NGC 7027 near 3.3 microns at very high resolution

    International Nuclear Information System (INIS)

    Lowe, R.P.; Moorhead, J.M.; Wehlau, W.H.; Maillard, J.P.

    1991-01-01

    A very high resolution spectrum is presented of the planetary nebula NGC 7027 over a 200/cm interval centered at 2950/cm, and the features found are described: (1) nebular continuum, (2) atomic recombination lines of H and He II, and (3) three broader emission features of uncertain origin. For the latter the first evidence is presented that the 3.46 micron feature and possibly the 3.40 micron feature are resolvable into a sequence of narrower features. The interpretation of the broader features is discussed in terms of the hypothesis of identification with emission by polycyclic aromatic hydrocarbons. 18 refs

  11. The practicality of high magnification imaging by positron emission

    International Nuclear Information System (INIS)

    Hulett, L.D. Jr.; Pendyala, S.

    1988-01-01

    The positron emission microscope has the capability of contrasting areas having high concentrations of monatomic vacancies and other defects. Since the positrons traveling through the specimen will have energies of the same magnitude as that of valence electrons, image contrast will be sensitive to the chemistry of the specimen. In the near future resolutions of 10 nm or lower will be achieved. Whether or not optical aberrations will permit one atom resolution is not clear. For one atom resolution to be obtained positron emission fluxes must be brightness enhanced to 10 11 sec/sup/minus/1/cm/sup/minus/2/ or greater. 5 refs., 1 fig

  12. Positron emission tomographic images and expectation maximization: A VLSI architecture for multiple iterations per second

    International Nuclear Information System (INIS)

    Jones, W.F.; Byars, L.G.; Casey, M.E.

    1988-01-01

    A digital electronic architecture for parallel processing of the expectation maximization (EM) algorithm for Positron Emission tomography (PET) image reconstruction is proposed. Rapid (0.2 second) EM iterations on high resolution (256 x 256) images are supported. Arrays of two very large scale integration (VLSI) chips perform forward and back projection calculations. A description of the architecture is given, including data flow and partitioning relevant to EM and parallel processing. EM images shown are produced with software simulating the proposed hardware reconstruction algorithm. Projected cost of the system is estimated to be small in comparison to the cost of current PET scanners

  13. The Neuro-PET: a new high-resolution 7-slice positron emission tomograph

    International Nuclear Information System (INIS)

    Brooks, R.A.; Sank, V.J.; Di Chiro, G.; Friauf, W.S.; Leighton, S.B.; Cascio, H.E.

    1982-01-01

    The Neuro-PET consists of 4 circular rings of 128 BGO detectors providing 7 simultaneous slices. At present the scanner is operating with only one ring, pending delivery of three more electronic chassis. Inter-plane septa of depleted uranium are used to shield out-of-plane activity and scatter, without interfering with the cross-slice images. Preliminary measurements of in-plane resolution, using a 1 mm dia. Ge-68-filled steel rod in a plastic phantom, give 6 mm full-width-at-half-maximum at the center of the image and 7 mm at a point 9 cm off center. Axial resolution was measured to be 10 mm. Sensitivity, as measured with a 20 cm diameter uniform phantom, is 53000, 44000 or 31000 counts/s/μCi/cc, depending on the energy threshold, which is switch-selectable at the console. Scatter was measured with a cold spot phantom by taking the ratio of apparent activity at the center of the cold spot to that in the surrounding area. The result for a 1 cm cold spot located near the periphery of the phantom was 33%, without software correction, and less than 20% for a 5 cm cold spot

  14. The Next-generation Berkeley High Resolution NO2 (BEHR NO2) Retrieval: Design and Preliminary Emissions Constraints

    Science.gov (United States)

    Laughner, J.; Cohen, R. C.

    2017-12-01

    Recent work has identified a number of assumptions made in NO2 retrievals that lead to biases in the retrieved NO2 column density. These include the treatment of the surface as an isotropic reflector, the absence of lightning NO2 in high resolution a priori profiles, and the use of monthly averaged a priori profiles. We present a new release of the Berkeley High Resolution (BEHR) OMI NO2 retrieval based on the new NASA Standard Product (version 3) that addresses these assumptions by: accounting for surface anisotropy by using a BRDF albedo product, using an updated method of regridding NO2 data, and revised NO2 a priori profiles that better account for lightning NO2 and daily variation in the profile shape. We quantify the effect these changes have on the retrieved NO2 column densities and the resultant impact these updates have on constraints of urban NOx emissions for select cities throughout the United States.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gillard, W

    2008-01-15

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

  16. High-resolution forest carbon stocks and emissions in the Amazon

    Science.gov (United States)

    G. P. Asner; George V. N. Powell; Joseph Mascaro; David E. Knapp; John K. Clark; James Jacobson; Ty Kennedy-Bowdoin; Aravindh Balaji; Guayana Paez-Acosta; Eloy Victoria; Laura Secada; Michael Valqui; R. Flint. Hughes

    2010-01-01

    Efforts to mitigate climate change through the Reduced Emissions from Deforestation and Degradation (REDD) depend on mapping and monitoring of tropical forest carbon stocks and emissions over large geographic areas. With a new integrated use of satellite imaging, airborne light detection and ranging, and field plots, we mapped aboveground carbon stocks and emissions at...

  17. High Resolution Atmospheric Inversion of Urban CO2 Emissions During the Dormant Season of the Indianapolis Flux Experiment (INFLUX)

    Science.gov (United States)

    Lauvaux, Thomas; Miles, Natasha L.; Deng, Aijun; Richardson, Scott J.; Cambaliza, Maria O.; Davis, Kenneth J.; Gaudet, Brian; Gurney, Kevin R.; Huang, Jianhua; O'Keefe, Darragh; hide

    2016-01-01

    Urban emissions of greenhouse gases (GHG) represent more than 70% of the global fossil fuel GHG emissions. Unless mitigation strategies are successfully implemented, the increase in urban GHG emissions is almost inevitable as large metropolitan areas are projected to grow twice as fast as the world population in the coming 15 years. Monitoring these emissions becomes a critical need as their contribution to the global carbon budget increases rapidly. In this study, we developed the first comprehensive monitoring systems of CO2 emissions at high resolution using a dense network of CO2 atmospheric measurements over the city of Indianapolis. The inversion system was evaluated over a 8-month period and showed an increase compared to the Hestia CO2 emission estimate, a state-of-the-art building-level emission product, with a 20% increase in the total emissions over the area (from 4.5 to 5.7 Metric Megatons of Carbon +/- 0.23 Metric Megatons of Carbon). However, several key parameters of the inverse system need to be addressed to carefully characterize the spatial distribution of the emissions and the aggregated total emissions.We found that spatial structures in prior emission errors, mostly undetermined, affect significantly the spatial pattern in the inverse solution, as well as the carbon budget over the urban area. Several other parameters of the inversion were sufficiently constrained by additional observations such as the characterization of the GHG boundary inflow and the introduction of hourly transport model errors estimated from the meteorological assimilation system. Finally, we estimated the uncertainties associated with remaining systematic errors and undetermined parameters using an ensemble of inversions. The total CO2 emissions for the Indianapolis urban area based on the ensemble mean and quartiles are 5.26 - 5.91 Metric Megatons of Carbon, i.e. a statistically significant difference compared to the prior total emissions of 4.1 to 4.5 Metric Megatons of

  18. Shielding design for positron emission tomography facility

    International Nuclear Information System (INIS)

    Abdallah, I.I.

    2007-01-01

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

  19. F-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Appearance of Extramedullary Hematopoesis in a Case of Primary Myelofibrosis

    Science.gov (United States)

    Mukherjee, Anirban; Bal, Chandrasekhar; Tripathi, Madhavi; Das, Chandan Jyoti; Shamim, Shamim Ahmed

    2017-01-01

    A 44-year-old female with known primary myelofibrosis presented with shortness of breath. High Resolution Computed Tomography thorax revealed large heterogeneously enhancing extraparenchymal soft tissue density mass involving bilateral lung fields. F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography revealed mildly FDG avid soft tissue density mass with specks of calcification involving bilateral lung fields, liver, and spleen. Subsequent histopathologic evaluation from the right lung mass was suggestive of extramedullary hematopoesis. PMID:28533647

  20. Construction of a quartz spherical analyzer: application to high-resolution analysis of the Ni Kα emission spectrum

    International Nuclear Information System (INIS)

    Honnicke, Marcelo Goncalves; Cusatis, Cesar

    2016-01-01

    The construction and characterization of a focusing X-ray spherical analyzer based on α-quartz 44̄04 are presented. For this study, the performance of the analyzer was demonstrated by applying it to a high-resolution X-ray spectroscopy study of theKα_1_,_2emission spectrum of Ni. An analytical representation based on physical grounds was assumed to model the shape of the X-ray emission lines. Satellite structures assigned to 3dspectator hole transitions were resolved and determined as well as their relative contribution to the emission spectrum. The present results on 1s"-"13d"-"1shake probabilities support a recently proposed calculation framework based on a multi-configuration atomic model.

  1. A High Resolution Technology-based Emissions Inventory for Nepal: Present and Future Scenario

    Science.gov (United States)

    Sadavarte, P.; Das, B.; Rupakheti, M.; Byanju, R.; Bhave, P.

    2016-12-01

    A comprehensive regional assessment of emission sources is a major hindrance for a complete understanding of the air quality and for designing appropriate mitigation solutions in Nepal, a landlocked country in foothills of the Himalaya. This study attempts, for the first time, to develop a fine resolution (1km × 1km) present day emission inventory of Nepal with a higher tier approach using our understanding of the currently used technologies, energy consumption used in various energy sectors and its resultant emissions. We estimate present-day emissions of aerosols (BC, OC and PM2.5), trace gases (SO2, CO, NOX and VOC) and greenhouse gases (CO2, N2O and CH4) from non-open burning sources (residential, industry, transport, commercial) and open-burning sources (agriculture and municipal solid waste burning) for the base year 2013. We used methodologies published in literatures, and both primary and secondary data to estimate energy production and consumption in each sector and its sub-sector and associated emissions. Local practices and activity rates are explicitly accounted for energy consumption and dispersed often under-documented emission sources like brick manufacturing, diesel generator sets, mining, stone crushing, solid waste burning and diesel use in farms are considered. Apart from pyrogenic source of CH4 emissions, methanogenic and enteric fermentation sources are also accounted. Region-specific and newly measured country-specific emission factors are used for emission estimates. Activity based proxies are used for spatial and temporal distribution of emissions. Preliminary results suggest that 80% of national energy consumption is in residential sector followed by industry (8%) and transport (7%). More than 90% of the residential energy is supplied by biofuel which needs immediate attention to reduce emissions. Further, the emissions would be compared with other contemporary studies, regional and global datasets and used in the model simulations to

  2. Monitoring Oilfield Operations and GHG Emissions Sources Using Object-based Image Analysis of High Resolution Spatial Imagery

    Science.gov (United States)

    Englander, J. G.; Brodrick, P. G.; Brandt, A. R.

    2015-12-01

    Fugitive emissions from oil and gas extraction have become a greater concern with the recent increases in development of shale hydrocarbon resources. There are significant gaps in the tools and research used to estimate fugitive emissions from oil and gas extraction. Two approaches exist for quantifying these emissions: atmospheric (or 'top down') studies, which measure methane fluxes remotely, or inventory-based ('bottom up') studies, which aggregate leakage rates on an equipment-specific basis. Bottom-up studies require counting or estimating how many devices might be leaking (called an 'activity count'), as well as how much each device might leak on average (an 'emissions factor'). In a real-world inventory, there is uncertainty in both activity counts and emissions factors. Even at the well level there are significant disagreements in data reporting. For example, some prior studies noted a ~5x difference in the number of reported well completions in the United States between EPA and private data sources. The purpose of this work is to address activity count uncertainty by using machine learning algorithms to classify oilfield surface facilities using high-resolution spatial imagery. This method can help estimate venting and fugitive emissions sources from regions where reporting of oilfield equipment is incomplete or non-existent. This work will utilize high resolution satellite imagery to count well pads in the Bakken oil field of North Dakota. This initial study examines an area of ~2,000 km2 with ~1000 well pads. We compare different machine learning classification techniques, and explore the impact of training set size, input variables, and image segmentation settings to develop efficient and robust techniques identifying well pads. We discuss the tradeoffs inherent to different classification algorithms, and determine the optimal algorithms for oilfield feature detection. In the future, the results of this work will be leveraged to be provide activity

  3. First Top-Down Estimates of Anthropogenic NOx Emissions Using High-Resolution Airborne Remote Sensing Observations

    Science.gov (United States)

    Souri, Amir H.; Choi, Yunsoo; Pan, Shuai; Curci, Gabriele; Nowlan, Caroline R.; Janz, Scott J.; Kowalewski, Matthew G.; Liu, Junjie; Herman, Jay R.; Weinheimer, Andrew J.

    2018-03-01

    A number of satellite-based instruments have become an essential part of monitoring emissions. Despite sound theoretical inversion techniques, the insufficient samples and the footprint size of current observations have introduced an obstacle to narrow the inversion window for regional models. These key limitations can be partially resolved by a set of modest high-quality measurements from airborne remote sensing. This study illustrates the feasibility of nitrogen dioxide (NO2) columns from the Geostationary Coastal and Air Pollution Events Airborne Simulator (GCAS) to constrain anthropogenic NOx emissions in the Houston-Galveston-Brazoria area. We convert slant column densities to vertical columns using a radiative transfer model with (i) NO2 profiles from a high-resolution regional model (1 × 1 km2) constrained by P-3B aircraft measurements, (ii) the consideration of aerosol optical thickness impacts on radiance at NO2 absorption line, and (iii) high-resolution surface albedo constrained by ground-based spectrometers. We characterize errors in the GCAS NO2 columns by comparing them to Pandora measurements and find a striking correlation (r > 0.74) with an uncertainty of 3.5 × 1015 molecules cm-2. On 9 of 10 total days, the constrained anthropogenic emissions by a Kalman filter yield an overall 2-50% reduction in polluted areas, partly counterbalancing the well-documented positive bias of the model. The inversion, however, boosts emissions by 94% in the same areas on a day when an unprecedented local emissions event potentially occurred, significantly mitigating the bias of the model. The capability of GCAS at detecting such an event ensures the significance of forthcoming geostationary satellites for timely estimates of top-down emissions.

  4. A high-resolution open biomass burning emission inventory based on statistical data and MODIS observations in mainland China

    Science.gov (United States)

    Xu, Y.; Fan, M.; Huang, Z.; Zheng, J.; Chen, L.

    2017-12-01

    Open biomass burning which has adverse effects on air quality and human health is an important source of gas and particulate matter (PM) in China. Current emission estimations of open biomass burning are generally based on single source (alternative to statistical data and satellite-derived data) and thus contain large uncertainty due to the limitation of data. In this study, to quantify the 2015-based amount of open biomass burning, we established a new estimation method for open biomass burning activity levels by combining the bottom-up statistical data and top-down MODIS observations. And three sub-category sources which used different activity data were considered. For open crop residue burning, the "best estimate" of activity data was obtained by averaging the statistical data from China statistical yearbooks and satellite observations from MODIS burned area product MCD64A1 weighted by their uncertainties. For the forest and grassland fires, their activity levels were represented by the combination of statistical data and MODIS active fire product MCD14ML. Using the fire radiative power (FRP) which is considered as a better indicator of active fire level as the spatial allocation surrogate, coarse gridded emissions were reallocated into 3km ×3km grids to get a high-resolution emission inventory. Our results showed that emissions of CO, NOx, SO2, NH3, VOCs, PM2.5, PM10, BC and OC in mainland China were 6607, 427, 84, 79, 1262, 1198, 1222, 159 and 686 Gg/yr, respectively. Among all provinces of China, Henan, Shandong and Heilongjiang were the top three contributors to the total emissions. In this study, the developed open biomass burning emission inventory with a high-resolution could support air quality modeling and policy-making for pollution control.

  5. Estimating Biogenic Non-Methane Hydrocarbon Emissions for the Wasatch Front Through a High-Resolution. Gridded, Biogenic Vola Tile Organic Compound Emissions Inventory

    Science.gov (United States)

    2002-01-01

    1-hour and proposed 8-hour National Ambient Air Quality Standards. Reactive biogenic (natural) volatile organic compounds emitted from plants have...uncertainty in predicting plant species composition and frequency. Isoprene emissions computed for the study area from the project’s high-resolution...Landcover Database (BELD 2), while monoterpene and other reactive volatile organic compound emission rates were almost 26% and 28% lower, respectively

  6. High-resolution inventory of NO emissions from agricultural soils over the Ile-de-France region

    Energy Technology Data Exchange (ETDEWEB)

    Rolland, M.-N. [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Gabrielle, B., E-mail: Benoit.Gabrielle@agroparistech.f [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Laville, P.; Cellier, P. [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Beekmann, M. [Laboratoire Inter-universitaire des Systemes Atmospheriques - CNRS, Universites Paris-Est and Paris 7, F-94 010 Creteil (France); Gilliot, J.-M.; Michelin, J.; Hadjar, D. [INRA, AgroParisTech, UMR 1091 Environnement et Grandes Cultures, F-78850 Grignon (France); Curci, G. [Dipartimento di Fisica - CETEMPS, Universita' degli Studi dell' Aquila, 67010 Coppito, L' Aquila (Italy)

    2010-03-15

    Arable soils are a significant source of nitric oxide (NO), a precursor of tropospheric ozone, and thereby contribute to ozone pollution. However, their actual impact on ozone formation is strongly related to their spatial and temporal emission patterns, which warrant high-resolution estimates. Here, we combined an agro-ecosystem model and geo-referenced databases to map these sources over the 12 000 km{sup 2} administrative region surrounding Paris, France, with a kilometric level resolution. The six most frequent arable crop species were simulated, with emission rates ranging from 1.4 kg N-NO ha{sup -1} yr{sup -1} to 11.1 kg N-NO ha{sup -1} yr{sup -1}. The overall emission factor for fertilizer-derived NO emissions was 1.7%, while background emissions contributed half of the total NO efflux. Emissions were strongly seasonal, being highest in spring due to fertilizer inputs. They were mostly sensitive to soil type, crops' growing season and fertilizer N rates. - The use of an agro-ecosystem model at regional scale makes it possible to map the emissions of nitric oxide from arable soils at a resolution compatible with tropospheric ozone models.

  7. In-situ positron emission of CO oxidation

    OpenAIRE

    Vonkeman, K.A.; Jonkers, G.; Wal, van der, S.W.A.; Santen, van, R.A.

    1993-01-01

    Using a Neuro ECAT positron tomog., the Positron Emission computed Tomog. (PET) was utilized to image the catalytic oxidn. of CO by using CO and CO2, labeled with short lived positron emitting nuclides. Studies were performed over highly dispersed CeO2/g-Al2O3 supported Pt and Rh catalysts. With a math. model of the reaction kinetics, based on the elementary steps of the catalytic reaction and partially on literature surface science data, the effect of CeO2 promotion and the presence of NO we...

  8. A new liquid xenon scintillation detector for positron emission tomography

    International Nuclear Information System (INIS)

    Chepel, V.Yu.

    1993-01-01

    A new positron-sensitive detector of annihilation photons filled with liquid xenon is proposed for positron emission tomography. Simultaneous detection of both liquid xenon scintillation and ionization current produces a time resolution of < 1 ns and a position resolution in the tangential direction of the tomograph ring is ∼ 1 mm and in the radial direction is ∼ 5 mm. The advantages of a tomograph with new detectors are discussed. New algorithms of Compton scattering can be used. (author)

  9. Positron emission tomographic imaging of tumors using monoclonal antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Zalutsky, M.R.

    1992-08-01

    This research project is developing methods for utilizing positron emission tomography (PET) to increase the clinical potential of radiolabeled monoclonal antibodies (MAbs). This report describes the development of methods for labeling MAbs and their fragments with positron-emitting halogen nuclides, fluorine-18 and iodine-124. These nulides were selected because of the widespread availability of F-18 and because of our extensive experience in the development of new protein radiohalogenation methods.

  10. High-resolution inventory of ammonia emissions from agricultural fertilizer in China from 1978 to 2008

    Science.gov (United States)

    Xu, P.; Liao, Y. J.; Lin, Y. H.; Zhao, C. X.; Yan, C. H.; Cao, M. N.; Wang, G. S.; Luan, S. J.

    2016-02-01

    The quantification of ammonia (NH3) emissions is essential to the more accurate quantification of atmospheric nitrogen deposition, improved air quality and the assessment of ammonia-related agricultural policy and climate mitigation strategies. The quantity, geographic distribution and historical trends of these emissions remain largely uncertain. In this paper, a new Chinese agricultural fertilizer NH3 (CAF_NH3) emissions inventory has been compiled that exhibits the following improvements: (1) a 1 × 1 km gridded map on the county level was developed for 2008; (2) a combined bottom-up and top-down method was used for the local correction of emission factors (EFs) and parameters; (3) the temporal patterns of historical time trends for 1978-2008 were estimated and the uncertainties were quantified for the inventories; and (4) a sensitivity test was performed in which a province-level disaggregated map was compared with CAF_NH3 emissions for 2008. The total CAF_NH3 emissions for 2008 were 8.4 TgNH3 yr-1 (a 6.6-9.8 Tg interquartile range). From 1978 to 2008, annual NH3 emissions fluctuated with three peaks (1987, 1996 and 2005), and total emissions increased from 3.2 to 8.4 Tg at an annual rate of 3.0 %. During the study period, the contribution of livestock manure spreading increased from 37.0 to 45.5 % because of changing fertilization practices and the rapid increase in egg, milk, and meat consumption. The average contribution of synthetic fertilizer, which has a positive effect on crop yields, was approximately 38.3 % (minimum: 33.4 %; maximum: 42.7 %). With rapid urbanization causing a decline in the rural population, the contribution of the rural excrement sector varied widely between 20.3 % and 8.5 %. The average contributions of cake fertilizer and straw returning were approximately 3.8 and 4.5 %, respectively, thus small and stable. Collectively, the CAF_NH3 emissions reflect the nation's agricultural policy to a certain extent. An effective approach to

  11. Development and evaluation of high-resolution regional emission inventory: A case study for Jiangsu Province, China

    Science.gov (United States)

    Zhao, Y.; Mao, P.; Zhou, Y.

    2017-12-01

    Improved emission inventories are crucial for better understanding atmospheric chemistry with air quality simulation at regional or local scales. Using the bottom-up approach, a high-resolution emission inventory was developed for Jiangsu China. Key parameters for over 6000 industrial sources were investigated, compiled and revised at plant level based on various data sources and on-site survey. Totally 56 NMVOCs samples were collected in 9 chemical plants and analyzed with a gas chromatography-mass spectrometry system. Source profiles of stack emissions from synthetic rubber, acetate fiber, polyether, vinyl acetate, and ethylene production, and those of fugitive emissions from ethylene, butanol and octanol, propylene epoxide, polyethylene and glycol production were obtained. Improvement of this provincial inventory was evaluated through comparisons with other inventories at larger spatial scales, using satellite observation and air quality modeling. Three inventories (national, regional, and provincial by this work) were applied in the Models-3/Community Multi-scale Air Quality (CMAQ) system to evaluate the model performances with different emission inputs. The best agreement between available ground observation and simulation was found when the provincial inventory was applied, indicated by the smallest normalized mean bias (NMB) and normalized mean errors (NME) for all the concerned species SO2, NO2, O3 and PM2.5. The result thus implied the advantage of improved emission inventory at local scale for high resolution air quality modeling. Under the unfavorable meteorology in which horizontal and vertical movement of atmosphere was limited, the simulated SO2 concentrations at downtown Nanjing (the capital city of Jiangsu) using the regional or national inventories were much higher than observation, implying overestimated urban emissions when economy or population densities were applied to downscale or allocate the emissions. With more accurate spatial distribution

  12. A high-resolution emission inventory of primary pollutants for the Huabei region, China

    Directory of Open Access Journals (Sweden)

    B. Zhao

    2012-01-01

    Full Text Available Huabei, located between 32° N and 42° N, is part of eastern China and includes administratively the Beijing and Tianjin Municipalities, Hebei and Shanxi Provinces, and Inner-Mongolia Autonomous Region. Over the past decades, the region has experienced dramatic changes in air quality and climate, and has become a major focus of environmental research in China. Here we present a new inventory of air pollutant emissions in Huabei for the year 2003 developed as part of the project Influence of Pollution on Aerosols and Cloud Microphysics in North China (IPAC-NC.

    Our estimates are based on data from the statistical yearbooks of the state, provinces and local districts, including major sectors and activities of power generation, industrial energy consumption, industrial processing, civil energy consumption, crop straw burning, oil and solvent evaporation, manure, and motor vehicles. The emission factors are selected from a variety of literature and those from local measurements in China are used whenever available. The estimated total emissions in the Huabei administrative region in 2003 are 4.73 Tg SO2, 2.72 Tg NOx (in equivalent NO2, 1.77 Tg VOC, 24.14 Tg CO, 2.03 Tg NH3, 4.57 Tg PM10, 2.42 Tg PM2.5, 0.21 Tg EC, and 0.46 Tg OC.

    For model convenience, we consider a larger Huabei region with Shandong, Henan and Liaoning Provinces included in our inventory. The estimated total emissions in the larger Huabei region in 2003 are: 9.55 Tg SO2, 5.27 Tg NOx (in equivalent NO2, 3.82 Tg VOC, 46.59 Tg CO, 5.36 Tg NH3, 10.74 Tg PM10, 5.62 Tg PM2.5, 0.41 Tg EC, and 0.99 Tg OC. The estimated emission rates are projected into grid cells at a horizontal resolution of 0.1° latitude by 0.1° longitude. Our gridded emission inventory consists of area sources, which are classified into industrial, civil, traffic, and

  13. Application of High Resolution Air-Borne Remote Sensing Observations for Monitoring NOx Emissions

    Science.gov (United States)

    Souri, A.; Choi, Y.; Pan, S.; Curci, G.; Janz, S. J.; Kowalewski, M. G.; Liu, J.; Herman, J. R.; Weinheimer, A. J.

    2017-12-01

    Nitrogen oxides (NOx=NO+NO2) are one of the air pollutants, responsible for the formation of tropospheric ozone, acid rain and particulate nitrate. The anthropogenic NOx emissions are commonly estimated based on bottom-up inventories which are complicated by many potential sources of error. One way to improve the emission inventories is to use relevant observations to constrain them. Fortunately, Nitrogen dioxide (NO2) is one of the most successful detected species from remote sensing. Although many studies have shown the capability of using space-borne remote sensing observations for monitoring emissions, the insufficient sample number and footprint of current measurements have introduced a burden to constrain emissions at fine scales. Promisingly, there are several air-borne sensors collected for NASA's campaigns providing high spatial resolution of NO2 columns. Here, we use the well-characterized NO2 columns from the Airborne Compact Atmospheric Mapper (ACAM) onboard NASA's B200 aircraft into a 1×1 km regional model to constrain anthropogenic NOx emissions in the Houston-Galveston-Brazoria area. Firstly, in order to incorporate the data, we convert the NO2 slant column densities to vertical ones using a joint of a radiative transfer model and the 1x1 km regional model constrained by P3-B aircraft measurements. After conducting an inverse modeling method using the Kalman filter, we find the ACAM observations are resourceful at mitigating the overprediction of model in reproducing NO2 on regular days. Moreover, the ACAM provides a unique opportunity to detect an anomaly in emissions leading to strong air quality degradation that is lacking in previous works. Our study provides convincing evidence that future geostationary satellites with high spatial and temporal resolutions will give us insights into uncertainties associated with the emissions at regional scales.

  14. Methyl jasmonate-induced emission of biogenic volatiles is biphasic in cucumber: a high-resolution analysis of dose dependence.

    Science.gov (United States)

    Jiang, Yifan; Ye, Jiayan; Li, Shuai; Niinemets, Ülo

    2017-07-20

    Methyl jasmonate (MeJA) is a key airborne elicitor activating jasmonate-dependent signaling pathways, including induction of stress-related volatile emissions, but how the magnitude and timing of these emissions scale with MeJA dose is not known. Treatments with exogenous MeJA concentrations ranging from mild (0.2 mM) to lethal (50 mM) were used to investigate quantitative relationships among MeJA dose and the kinetics and magnitude of volatile release in Cucumis sativus by combining high-resolution measurements with a proton-transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) and GC-MS. The results highlighted biphasic kinetics of elicitation of volatiles. The early phase, peaking in 0.1-1 h after the MeJA treatment, was characterized by emissions of lipoxygenase (LOX) pathway volatiles and methanol. In the subsequent phase, starting in 6-12 h and reaching a maximum in 15-25 h after the treatment, secondary emissions of LOX compounds as well as emissions of monoterpenes and sesquiterpenes were elicited. For both phases, the maximum emission rates and total integrated emissions increased with applied MeJA concentration. Furthermore, the rates of induction and decay, and the duration of emission bursts were positively, and the timing of emission maxima were negatively associated with MeJA dose for LOX compounds and terpenoids, except for the duration of the first LOX burst. These results demonstrate major effects of MeJA dose on the kinetics and magnitude of volatile response, underscoring the importance of biotic stress severity in deciphering the downstream events of biological impacts. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. A high-resolution air pollutants emission inventory in 2013 for the Beijing-Tianjin-Hebei region, China

    Science.gov (United States)

    Qi, Ji; Zheng, Bo; Li, Meng; Yu, Fang; Chen, Chuchu; Liu, Fei; Zhou, Xiafei; Yuan, Jing; Zhang, Qiang; He, Kebin

    2017-12-01

    We developed a high-resolution Beijing-Tianjin-Hebei (BTH) regional air pollutants emission inventory for the year 2013. The inventory was established using a bottom-up approach based on facility-level activity data obtained from multiple data sources. The estimates from the BTH 2013 emission inventory show that the total emissions of SO2, NOX, PM2.5, PM10, CO, NMVOC, NH3, BC, and OC were 2,305, 2,686, 1,090, 1,494, 20,567, 2,207, 623, 160, and 254 Gg, respectively. The industry sector is the largest emissions source for SO2, NOX, PM2.5, PM10, CO, and NMVOC in the BTH region, contributing 72.6%, 43.7%, 59.6%, 64.7%, 60.3%, and 70.4% of the total emissions, respectively. Power plants contributed 11.8% and 23.3% of the total SO2 and NOX emissions, respectively. The transportation sector contributed 28.9% of the total NOX emissions. Emissions from the residential sector accounted for 31.3%, 21.5%, 46.6% and 71.7% of the total PM2.5, NMVOC, BC and OC emissions, respectively. In addition, more than 90% of the total NH3 emissions originate from the agriculture sector, with 44.2% from fertilizer use and 47.7% from livestock. The spatial distribution results illustrate that air pollutant emissions are mainly distributed over the eastern and southern BTH regions. Beijing, Tianjin, Shijiazhuang, Tangshan and Handan are the major contributors of air pollutants. The major NMVOC species in the BTH region are ethylene, acetylene, ethane and toluene. Ethylene is the biggest contributor in Tianjin and Hebei. The largest contributor in Beijing is toluene. There is relatively low uncertainty in SO2 and NOX emission estimates, medium uncertainty in PM2.5, PM10 and CO emission estimates, and high uncertainties in VOC, NH3, BC and OC emission estimates. The proposed policy recommendations, based on the BTH 2013 emission inventory, would be helpful to develop strategies for air pollution control.

  16. High Resolution CH4 Emissions and Dissolved CH4 Measurements Elucidate Surface Gas Exchange Processes in Toolik Lake, Arctic Alaska

    Science.gov (United States)

    Del Sontro, T.; Sollberger, S.; Kling, G. W.; Shaver, G. R.; Eugster, W.

    2013-12-01

    Approximately 14% of the Alaskan North Slope is covered in lakes of various sizes and depths. Diffusive carbon emissions (CH4 and CO2) from these lakes offset the tundra sink by ~20 %, but the offset would substantially increase if ebullitive CH4 emissions were also considered. Ultimately, arctic lake CH4 emissions are not insignificant in the global CH4 budget and their contribution is bound to increase due to impacts from climate change. Here we present high resolution CH4 emission data as measured via eddy covariance and a Los Gatos gas analyzer during the ice free period from Toolik Lake, a deep (20 m) Arctic lake located on the Alaskan North Slope, over the last few summers. Emissions are relatively low (Gatos gas analyzer. Thus, having both the flux and the CH4 gradient across the air-water interface measured directly, we can calculate k and investigate the processes influencing CH4 gas exchange in this lake. Preliminary results indicate that there are two regimes in wind speed that impact k - one at low wind speeds up to ~5 m s-1 and another at higher wind speeds (max ~10 m s-1). The differential wind speeds during night and day may compound the effect of convective mixing and cause the diurnal variation in observed fluxes.

  17. Ultra High Resolution Imaging of Enceladus Tiger Stripe Thermal Emission with Cassini CIRS

    Science.gov (United States)

    Spencer, John R.; Gorius, Nicolas; Howett, Carly; Verbiscer, Anne J.; Cassini CIRS Team

    2017-10-01

    In October 2015, Cassini flew within 48 km of Enceladus’ south pole. The spacecraft attitude was fixed during the flyby, but the roll angle of the spacecraft was chosen so that the remote sensing instrument fields of view passed over Damascus, Baghdad, and Cairo Sulci. The Composite Infrared Spectrometer (CIRS) instrument obtained a single interferometer scan during the flyby, using a special mode, enabled by a flight software update, which bypassed numerical filters to improve the fidelity of the interferograms. This generated a total of 11 interferograms, at 5 contiguous spatial locations for each of the 7 - 9 micron (FP4) and 9 - 17 micron (FP3) focal planes, and a single larger field of view for the 17 - 500 micron focal plane (FP1). Strong spikes were seen in the interferograms when crossing each of the sulci, due to the rapid passage of warm material through the field of view. For FP3 and FP4, the temporal variations of the signals from the 5 contiguous detectors can be used to generated 5-pixel-wide images of the thermal emission, which show excellent agreement between the two focal planes. FP3 and FP4 spatial resolution, limited along track by the 5 msec time sampling of the interferogram, and across track by the CIRS field of view, is a remarkable 40 x 40 meters. At this resolution, the tiger stripe thermal emission shows a large amount of structure, including both continuous emission along the fractures, discrete hot spots less than 100 meters across, and extended emission with complex structure.

  18. Positron emission tomography in oncology. Council on Scientific Affairs

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This report describes the current and potential uses of positron emission tomography in clinical medicine and research related to oncology. Assessment will be possible of metabolism and physiology of tumors and their effects on adjacent tissues. Specific probes are likely to be developed for target sites on tumors, including monoclonal antibodies and specific growth factors that recognize tumors. To date, most oncological applications of positron emission tomography tracers have been qualitative; in the future, quantitative metabolic measurements should aid in the evaluation of tumor biology and response to treatment. 41 references

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

    International Nuclear Information System (INIS)

    Bauer, R.

    1994-01-01

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

  20. High resolution emission spectra of H2 and D2 near 80 nm

    International Nuclear Information System (INIS)

    Larzilliere, M.; Roncin, J.-Y.; Launay, F.

    1980-01-01

    A few lines have been observed in the far ultraviolet emission spectrum of molecular hydrogen and deuterium. They are assigned to transitions from levels of the 3pπD 1 PIsub(u)sup(-) state, lying above the dissociation limit into H(ls) + H(n=2), near 84.5 nm, and, for some of them, above the first ionization limit near 80.4 nm, the lower state being X 1 Σsub(g)sup(+) (v''=1). This is in fair agreement with measured predissociation and preionization yields. Accurate line position measurements lead to molecular constants in very good agreement with theoretical calculations

  1. High-Resolution Electron-Impact Study of the Far-Ultraviolet Emission Spectrum of Molecular Hydrogen

    Science.gov (United States)

    Liu, Xian-Ming; Ahmed, Syed M.; Multari, Rosalie A.; James, Geoffrey K.; Ajello, Joseph M.

    1995-01-01

    The emission spectrum of molecular hydrogen produced by electron-impact excitation at 100 eV has been measured in the wavelength range 1140-1690 A. High-resolution, optically thin spectra (delta(lambda) = 0.136 A) of the far-ultraviolet (FUV) Lyman and Werner band systems have been obtained with a newly constructed 3 m spectrometer. Synthetic spectral intensities based on the transition probabilities calculated by Abgrall et al. are in very good agreement with experimentally observed intensities. Previous modeling that utilized Allison & Daigarno band transition probabilities with Hoenl-London factors breaks down when the transition moment has significant J dependence or when ro-vibrational coupling is significant. Ro-vibrational perturbation between upsilon = 14 of the B(sup 1)Sigma(sup +, sub u) state and upsilon = 3 of the C(sup 1)Pi(sub u) state and the rotational dependence of the transition moment in the bands of the Lyman system are examined. Complete high-resolution experimental reference FUV spectra, together with the model synthetic spectra based on the Abgrall transition probabilities, are presented. An improved calibration standard is obtained, and an accurate calibration of the 3 m spectrometer has been achieved.

  2. High resolution study of Kβ' and Kβ1,3 X-ray emission lines from Mn-compounds

    International Nuclear Information System (INIS)

    Limandri, S.; Ceppi, S.; Tirao, G.; Stutz, G.; Sanchez, C.G.; Riveros, J.A.

    2010-01-01

    High-resolutionemission spectra of several manganese compounds were measured in order to characterize the dependence of the Kβ' and Kβ 1,3 features, on the chemical environment. High resolution spectra were obtained using a non-conventional spectrometer based on quasi-back-diffraction geometry at National Synchrotron Light Laboratory (LNLS). It was found that the energy of the Kβ' satellite structure relative to the main Kβ 1,3 line decreases linearly with the formal oxidation state for Mn-O systems. A noticeable dispersion of the relative Kβ' energy for different Mn 2+ compounds could be observed. The dependence of the Kβ' satellite line on the net charge and the effective 3d spin in Mn 2+ compounds was investigated. Calculations of the net charge and the effective 3d spin were performed within the density-functional theory using the package SIESTA. A direct relation between this dispersion and the effective Mn 3d spin was found.

  3. Comparison of Gas Emission Crater Geomorphodynamics on Yamal and Gydan Peninsulas (Russia, Based on Repeat Very-High-Resolution Stereopairs

    Directory of Open Access Journals (Sweden)

    Alexander Kizyakov

    2017-10-01

    Full Text Available Gas Emission Craters (GEC represent a new phenomenon in permafrost regions discovered in the north of West Siberia. In this study we use very-high-resolution Worldview satellite stereopairs and Resurs-P images to reveal and measure the geomorphic features that preceded and followed GEC formation on the Yamal and Gydan peninsulas. Analysis of DEMs allowed us to: (1 distinguish different terrain positions of the GEC, at the foot of a gentle slope (Yamal, and on an upper edge of a terrace slope; (2 notice that the formation of both Yamal and Gydan GECs were preceded by mound development; (3 measure a funnel-shaped upper part and a cylindrical lower part for each crater; (4 and measure the expansion and plan form modification of GECs. Although the general characteristics of both craters are similar, there are differences when comparing both key sites in detail. The height of the mound and diameter of the resulting GEC in Yamal exceeds that in Gydan; GEC-1 was surrounded by a well-developed parapet, while AntGEC did not show any considerable accumulative body. Thus, using very-high-resolution remote sensing data allowed us to discriminate geomorphic features and relief positions characteristic for GEC formation. GECs are a potential threat to commercial facilities in permafrost and indigenous settlements, especially because at present there is no statistically significant number of study objects to identify the local environmental conditions in which the formation of new GEC is possible.

  4. Positron emission tomographic imaging of cardiac sympathetic innervation and function

    International Nuclear Information System (INIS)

    Goldstein, D.S.; Chang, P.C.; Eisenhofer, G.; Miletich, R.; Finn, R.; Bacher, J.; Kirk, K.L.; Bacharach, S.; Kopin, I.J.

    1990-01-01

    Sites of uptake, storage, and metabolism of [ 18 F]fluorodopamine and excretion of [ 18 F]fluorodopamine and its metabolites were visualized using positron emission tomographic (PET) scanning after intravenous injection of the tracer into anesthetized dogs. Radioactivity was concentrated in the renal pelvis, heart, liver, spleen, salivary glands, and gall bladder. Uptake of 18F by the heart resulted in striking delineation of the left ventricular myocardium. Pretreatment with desipramine markedly decreased cardiac positron emission, consistent with dependence of the heart on neuronal uptake (uptake-1) for removal of circulating catecholamines. In reserpinized animals, cardiac positron emission was absent within 30 minutes after injection of [ 18 F]-6-fluorodopamine, demonstrating that the emission in untreated animals was from radioactive labeling of the sympathetic storage vesicles. Decreased positron emission from denervated salivary glands confirmed that the tracer was concentrated in sympathetic neurons. Radioactivity in the gall bladder and urinary system depicted the hepatic and renal excretion of the tracer and its metabolites. Administration of tyramine or nitroprusside increased and ganglionic blockade with trimethaphan decreased the rate of loss of myocardial radioactivity. The results show that PET scanning after administration of [ 18 F]fluorodopamine can be used to visualize sites of sympathetic innervation, follow the metabolism and renal and hepatic excretion of catecholamines, and examine cardiac sympathetic function

  5. Long-range transport biomass burning emissions to the Himalayas: insights from high-resolution aerosol mass spectrometer

    Science.gov (United States)

    Xu, J.; Zhang, X.; Liu, Y.; Shichang, K.; Ma, Y.

    2017-12-01

    An intensive measurement was conducted at a remote, background, and high-altitude site (Qomolangma station, QOMS, 4276 m a.s.l.) in the northern Himalayas, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) along with other collocated instruments. The field measurement was performed from April 12 to May 12, 2016 to chemically characterize high time-resolved submicron particulate matter (PM1) and obtain the influence of biomass burning emissions to the Himalayas, frequently transported from south Asia during pre-monsoon season. Two high aerosol loading periods were observed during the study. Overall, the average (± 1σ) PM1 mass concentration was 4.44 (± 4.54) µg m-3 for the entire study, comparable with those observed at other remote sites worldwide. Organic aerosols (OA) was the dominant PM1 species (accounting for 54.3% of total PM1 mass on average) and its contribution increased with the increase of total PM1 mass loading. The average size distributions of PM1 species all peaked at an overlapping accumulation mode ( 500 nm), suggesting that aerosol particles were internally well-mixed and aged during long-range transportations. Positive matrix factorization (PMF) analysis on the high-resolution organic mass spectra identified three distinct OA factors, including a biomass burning related OA (BBOA, 43.7%) and two oxygenated OA (Local-OOA and LRT-OOA; 13.9% and 42.4%) represented sources from local emissions and long-range transportations, respectively. Two polluted air mass origins (generally from the west and southwest of QOMS) and two polluted episodes with enhanced PM1 mass loadings and elevated BBOA contributions were observed, respectively, suggesting the important sources of wildfires from south Asia. One of polluted aerosol plumes was investigated in detail to illustrate the evolution of aerosol characteristics at QOMS driving by different impacts of wildfires, air mass origins, meteorological conditions and

  6. 3D fast reconstruction in positron emission tomography

    International Nuclear Information System (INIS)

    Egger, M.L.; Scheurer, A. Hermann; Joseph, C.; Morel, C.

    1996-01-01

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

  7. Time-of-flight positron emission tomography and associated detectors

    International Nuclear Information System (INIS)

    Vacher, J.; Allemand, R.; Campagnolo, R.

    1983-04-01

    An analysis of the timing capabilities of the detectors (scintillators and photomultipliers) in time-of-flight positron emission tomography is presented. The advantages of BaF 2 compared with CsF for the futur tomographs are evaluated [fr

  8. Cobalt-55 positron emission tomography in recurrent ischaemic stroke

    NARCIS (Netherlands)

    De Reuck, J; Santens, P; Keppens, J; De Bleecker, J; Strijckmans, K; Goethals, P; Lemahieu, [No Value; Korf, J

    The present study investigates if Cobalt-55 (Co-55) positron emission tomography (PET) allows us to distinguish and detect recent, recurrent strokes in patients who had already suffered a previous infarct in the same vascular territory. Fourteen patients with recurrent strokes underwent a Co-55 PET

  9. Detectors, sampling, shielding, and electronics for positron emission tomography

    International Nuclear Information System (INIS)

    Derenzo, S.E.

    1981-08-01

    A brief discussion of the important design elements for positron emission tomographs is presented. The conclusions are that the instrumentation can be improved by the use of larger numbers of small, efficient detectors closely packed in many rings, the development of new detector materials, and novel electronic designs to reduce the deadtime and increase maximum event rates

  10. Measurement of absolute bone blood flow by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nahmias, C.; Cockshott, W.P.; Garnett, E.S.; Belbeck, L.W.

    1986-03-01

    A method of measuring bone blood flow has been developed using /sup 18/F sodium fluoride and positron emission tomography. The blood flow levels are in line with those obtained experimentally from microsphere embolisation. This investigative method could be applied to elucidate a number of clinical questions involving bone perfusion.

  11. Positron emission tomography/computed tomography scanning for ...

    African Journals Online (AJOL)

    Background: Although the site of nosocomial sepsis in the critically ill ventilated patient is usually identifiable, it may remain occult, despite numerous investigations. The rapid results and precise anatomical location of the septic source using positron emission tomography (PET) scanning, in combination with computed ...

  12. MR imaging and positron emission tomography of cortical heterotopia

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. MR imaging and positron emission tomography of cortical heterotopia

    International Nuclear Information System (INIS)

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

    1985-01-01

    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 18 F-2-deoxyglucose

  14. Positron emission tomography for staging of oesophageal and gastroesophageal malignancy

    NARCIS (Netherlands)

    Kole, AC; Plukker, JT; Nieweg, OE; Vaalburg, W

    Positron emission tomography (PET) with [F-18]-fluoro-2-deoxy-D-glucose (FDG) was prospectively investigated as a means of detecting metastatic disease in patients with oesophageal tumours and compared with computerized tomography (CT), with the surgical findings as a gold standard. Twenty-six

  15. Amyloid-β positron emission tomography imaging probes

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  16. Positron emission tomography of incidentally detected small pulmonary nodules

    DEFF Research Database (Denmark)

    Fischer, B M; Mortensen, J; Dirksen, A

    2004-01-01

    The aim of this study was to assess the value of fluorodeoxyglucose positron emission tomography (FDG PET) imaging of small pulmonary nodules incidentally detected by spiral computed tomography (CT) in a high-risk population. Ten patients (five females, five males, aged 54-72 years) were recruited...

  17. Positron Emission Tomography : background, possibilities and perspectives in neuroscience

    NARCIS (Netherlands)

    Paans, AMJ

    Positron Emission Tomography (PET) is a method for determining biochemical and physiological processes in vivo in a quantitative way. This includes the measurement of the pharmacokinetics of labeled drugs and the measurement of the effects of drugs and/or therapy on metabolism. Also deviations of

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

    International Nuclear Information System (INIS)

    Steinling, M.; Samson, Y.

    1999-01-01

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

  19. Positron emission tomography in presurgical diagnosis of partial epilepsies

    International Nuclear Information System (INIS)

    Hajek, M.; Leenders, K.L.; Wieser, H.G.

    1992-01-01

    We present results of studies in which positron emission tomography was applied to the presurgical evaluation of epileptics. Emphasis is placed on results of PET studies with various tracers in partial epilepsies and on the use of PET in age-related epileptic syndromes in children. (orig.) [de

  20. Serotonin synthesis studied with positron emission tomography, (PET)

    DEFF Research Database (Denmark)

    Honoré, Per Gustaf Hartvig; Lundquist, Pinelopi

    Positron emission tomography (PET) has the potential to study the biosynthesis and release of serotonin (5HT) at brain serotonergic neurons. PET requires probe compounds with specific attributes to enable imaging and quantification of biological processes. This section focuses on probes to measure...

  1. Quantification in dynamic and small-animal positron emission tomography

    NARCIS (Netherlands)

    Disselhorst, Johannes Antonius

    2011-01-01

    This thesis covers two aspects of positron emission tomography (PET) quantification. The first section addresses the characterization and optimization of a small-animal PET/CT scanner. The sensitivity and resolution as well as various parameters affecting image quality (reconstruction settings, type

  2. High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential

    Energy Technology Data Exchange (ETDEWEB)

    Uhlig, J.; Doriese, W. B.; Fowler, J. W.; Swetz, D. S.; Jaye, C.; Fischer, D. A.; Reintsema, C. D.; Bennett, D. A.; Vale, L. R.; Mandal, U.; O' Neil, G. C.; Miaja-Avila, L.; Joe, Y. I.; El Nahhas, A.; Fullagar, W.; Parnefjord Gustafsson, F.; Sundström, V.; Kurunthu, D.; Hilton, G. C.; Schmidt, D. R.; Ullom, J. N.

    2015-04-21

    X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low efficiency of wavelength-dispersive X-ray spectrometer technology has limited the use of XES, especially in combination with weaker laboratory X-ray sources. More efficient energy-dispersive detectors have either insufficient energy resolution because of the statistical limits described by Fano or too low counting rates to be of practical use. This paper updates an approach to high-resolution X-ray emission spectroscopy that uses a microcalorimeter detector array of superconducting transition-edge sensors (TESs). TES arrays are discussed and compared with conventional methods, and shown under which circumstances they are superior. It is also shown that a TES array can be integrated into a table-top time-resolved X-ray source and a soft X-ray synchrotron beamline to perform emission spectroscopy with good chemical sensitivity over a very wide range of energies.

  3. 77 FR 21783 - Guidance on Media Fills for Validation of Aseptic Preparations for Positron Emission Tomography...

    Science.gov (United States)

    2012-04-11

    ...] Guidance on Media Fills for Validation of Aseptic Preparations for Positron Emission Tomography Drugs... Aseptic Preparations for Positron Emission Tomography (PET) Drugs.'' This guidance is intended to help... Preparations for Positron Emission Tomography (PET) Drugs.'' Most PET drugs are designed for parenteral...

  4. Positron Emission Tomography Particle tracking using cluster analysis

    International Nuclear Information System (INIS)

    Gundogdu, O.

    2004-01-01

    Positron Emission Particle Tracking was successfully used in a wide range of industrial applications. This technique primarily uses a single positron emitting tracer particle. However, using multiple particles would provide more comparative information about the physical processes taking place in a system such as mixing or fluidised beds. In this paper, a unique method that enables us to track more than one particle is presented. This method is based on the midpoint of the closest distance between two trajectories or coincidence vectors. The technique presented in this paper employs a clustering method

  5. Positron Emission Tomography Particle tracking using cluster analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gundogdu, O. [University of Birmingham, School of Physics and Astronomy, Birmingham, B15 2TT (United Kingdom)]. E-mail: o.gundogdu@surrey.ac.uk

    2004-12-01

    Positron Emission Particle Tracking was successfully used in a wide range of industrial applications. This technique primarily uses a single positron emitting tracer particle. However, using multiple particles would provide more comparative information about the physical processes taking place in a system such as mixing or fluidised beds. In this paper, a unique method that enables us to track more than one particle is presented. This method is based on the midpoint of the closest distance between two trajectories or coincidence vectors. The technique presented in this paper employs a clustering method.

  6. Images to visualize the brain. PET: Positron Emission Tomography

    International Nuclear Information System (INIS)

    1992-01-01

    Diagnosis instrument and research tool, Positron Emission Tomography permits advanced technological developments on positron camera, on molecule labelling and principally on very complex 3D image processing. Cyceron Centre in Caen-France works on brain diseases and try to understand the mechanism of observed troubles and to assess the treatment efficiency with PET. Service Hospitalier Frederic Joliot of CEA-France establishes a mapping of cognitive functions in PET as vision areas, anxiety regions, brain organization of language, different attention forms, voluntary actions and motor functions

  7. Positron emission tomography in a national research centre

    International Nuclear Information System (INIS)

    Weinreich, R.

    1989-01-01

    The example of the Paul Scherrer Institute shows that positron emission tomography can be implanted successfully as spin-off into an appropriate environment. The adaption to the existing irradiation facilities of the technique of production of the short-lived positron emitters is complex. However, the basic necessities of a tomography programme can be covered. Moreover, the relatively high energy of the institute's injector cyclotron allows additional production of rare-used longer-lived positron emitters. The scanner exceeded the guaranteed specifications. With respect to the somewhat lower availability of beam time compared to a usual baby cyclotron, the research programme must not be very patient-intense. A strong participation of the pharmaceutical industry has directed research priorities into the pharmacological area. (orig.) [de

  8. Occipital lobe infarction and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tagawa, Koichi; Nagata, Ken; Shishido, Fumio (Research Inst. of Brain and Blood Vessels, Akita (Japan))

    1990-08-01

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

  9. Occipital lobe infarction and positron emission tomography

    International Nuclear Information System (INIS)

    Tagawa, Koichi; Nagata, Ken; Shishido, Fumio

    1990-01-01

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

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

    International Nuclear Information System (INIS)

    Paez Gutierrez, Diana Isabel; De los Reyes, Amelia; Llamas Olier, Augusto

    2007-01-01

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

  11. Nuclear medicine and positron emission tomography: An overview

    International Nuclear Information System (INIS)

    McCarthy, T.J.; Schwarz, S.W.; Welch, M.J.

    1994-01-01

    Nuclear medicine is the field of medical practice that involves the oral or intravenous administration of radioactive materials for use in diagnosis and therapy. The majority of radiopharmaceutical available are used for diagnostic purposes. These involve the determination of organ function, shape, or position from an image of the radioactivity distribution within an organ or at a location within the body. After administration, the radiopharmaceutical localizes within an organ or target tissue due to its biological or physiologic characteristics. This diagnostic capability is usually the result of the emission of gamma radiation from the radiopharmaceutical localized within an organ. This allows for external detection and imaging using a special type of camera known as a gamma camera. When a positron-emitting radionuclide decays, a positron (positive electron) is emitted from the nucleus. The positron then annihilates with an electron, resulting in the release of energy in the form of two 511-KeV γ-rays at 180 degree to one another. The energy of these photons is sufficient to pass through tissue. Thus, placing a series of detectors around the patient allows technicians to monitor the emission of both of the photons that result from a single positron annihilation. this ultimately allows an accurate quantification of the distribution of radioactivity in the body not possible when only a single γ-ray is emitted

  12. Clinical applications of positron emission tomography at Montreal Neurological Institute

    International Nuclear Information System (INIS)

    Morgan, P.P.

    1983-01-01

    The Montreal Neurological Institute occupies a leading position in positron emission tomography (PET) of the brain with the help of the following three techological gains: they have acquired a 'Therascan' positron emission tomograph manufactured by Atomic Energy of Canada Ltd.; also, a 'Baby Cyclotron' manufactured by Japan Steel Works Ltd.; and they have written a computer program to display the results in colour. Four short-lived isotopes are used; 11 C, 15 O, 18 F, 13 N. Studies of the oxygen uptake of tumours, their glucose metabolism (as monitored by 18 F labelled 2-fluoro-2-deoxyglucose), and their uptake of therapeutic agents, provide valuable research and diagnostic information. PET is also being used to study epilepsy and cerebrovascular disease

  13. Positron emission zone plate holography for particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Gundogdu, O. [University of Birmingham, School of Physics and Astronomy, Birmingham B15 2TT (United Kingdom)]. E-mail: o.gundogdu@surrey.ac.uk

    2006-01-15

    Positron Emission Particle Tracking (PEPT) is a powerful non-invasive technique that has been used extensively for tracking a single particle. In this paper, we present a study of zone plate holography method in order to track multiple particles, mainly two particles. The main aim is to use as small number of events as possible in the order to make it possible to track particles in fast moving industrial systems. A zone plate with 100% focal efficiency is simulated and applied to the Positron Emission Tomography (PET) data for multiple particle tracking. A simple trajectory code was employed to explore the effects of the nature of the experimental trajectories. A computer holographic reconstruction code that simulates optical reconstruction was developed. The different aspects of the particle location, particle activity ratios for enabling tagging of particles and zone plate and hologram locations are investigated. The effect of the shot noise is investigated and the limitations of the zone plate holography are reported.

  14. Positron emission zone plate holography for particle tracking

    International Nuclear Information System (INIS)

    Gundogdu, O.

    2006-01-01

    Positron Emission Particle Tracking (PEPT) is a powerful non-invasive technique that has been used extensively for tracking a single particle. In this paper, we present a study of zone plate holography method in order to track multiple particles, mainly two particles. The main aim is to use as small number of events as possible in the order to make it possible to track particles in fast moving industrial systems. A zone plate with 100% focal efficiency is simulated and applied to the Positron Emission Tomography (PET) data for multiple particle tracking. A simple trajectory code was employed to explore the effects of the nature of the experimental trajectories. A computer holographic reconstruction code that simulates optical reconstruction was developed. The different aspects of the particle location, particle activity ratios for enabling tagging of particles and zone plate and hologram locations are investigated. The effect of the shot noise is investigated and the limitations of the zone plate holography are reported

  15. A full-sky, high-resolution atlas of galactic 12 μm dust emission with WISE

    International Nuclear Information System (INIS)

    Meisner, Aaron M.; Finkbeiner, Douglas P.

    2014-01-01

    We describe our custom processing of the entire Wide-field Infrared Survey Explorer (WISE) 12 μm imaging data set, and present a high-resolution, full-sky map of diffuse Galactic dust emission that is free of compact sources and other contaminating artifacts. The principal distinctions between our resulting co-added images and the WISE Atlas stacks are our removal of compact sources, including their associated electronic and optical artifacts, and our preservation of spatial modes larger than 1.°5. We provide access to the resulting full-sky map via a set of 430 12.°5 × 12.°5 mosaics. These stacks have been smoothed to 15'' resolution and are accompanied by corresponding coverage maps, artifact images, and bit-masks for point sources, resolved compact sources, and other defects. When combined appropriately with other mid-infrared and far-infrared data sets, we expect our WISE 12 μm co-adds to form the basis for a full-sky dust extinction map with angular resolution several times better than Schlegel et al.

  16. Possibilities of High Resolution Inductively Coupled Plasma Optical Emission Spectrometry in the Determination of Trace Elements in Environmental Materials

    Directory of Open Access Journals (Sweden)

    Nikolaya Velitchkova

    2013-01-01

    Full Text Available This paper presents new quantitative data for the spectral interferences obtained by high resolution 40.68 MHz radial viewing inductively coupled plasma optical emission spectrometry (HR-ICP-OES in the determination of Zn, Cd, Sb, Cu, Mn, Pb, Sn, Cr, U, and Ba in environmental materials in the presence of a complex matrix, containing Al, Ca, Fe, Mg, and Ti. The -concept for quantification of spectral interferences was used. The optimum line selection for trace analysis of a variety of multicomponent matrices requires the choice of prominent lines, which are free or negligibly influenced by line interference problems. The versatility of -concept as basic methodology was experimentally demonstrated in the determination of trace of elements in soil and drinking water. The detection limits are lower in comparison with corresponding threshold concentration levels for soil and drinking water in accordance with environmental regulations. This paper shows the possibilities of present day ICP-OES equipment in the direct determination of trace elements (without preconcentration of impurities in environmental samples.

  17. Application of positron emission tomography in the heart

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This report discusses experimental and clinical applications of positron emission tomography to the heart, including measurements of blood flow to the myocardium and studies of metabolism and experimental injury. Most initial clinical studies have concentrated on ischemic heart disease, but the technique also has potential for investigation of cardiomyopathies, studying the neural control of the heart, and evaluating the effects of drugs on cardiac tissues

  18. Photon emission by electrons and positrons traversing thin single crystal

    International Nuclear Information System (INIS)

    Ol'chak, A.S.

    1984-01-01

    Radiation emission by planar channeled particles (electrons, positrons) in a thin single crystal of thickness L is considered. It is shown that for L approximately πb/THETAsub(L) (b is the lattice constant, THETA sub(L) the Lindhard angle) besides the main spontaneous channeling maxima there exist auxiliary interference maxima, the positions of all the maxima depending on L. The dependence of the radiation spectral intensity on crystal thickness is discussed

  19. Contribution of positron emission tomography in pleural disease.

    OpenAIRE

    Duysinx, Bernard; Corhay, Jean-Louis; Larock, Marie-Paule; Withofs, Nadia; Bury, Thierry; Hustinx, Roland; Louis, Renaud

    2010-01-01

    INTRODUCTION: Positron emission tomography (PET) now plays a clear role in oncology, especially in chest tumours. We discuss the value of metabolic imaging in characterising pleural pathology in the light of our own experience and review the literature. BACKGROUND: PET is particularly useful in characterising malignant pleural pathologies and is a factor of prognosis in mesothelioma. Metabolic imaging also provides clinical information for staging lung cancer, in researching the primary tumou...

  20. Simulated annealing image reconstruction for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sundermann, E; Lemahieu, I; Desmedt, P [Department of Electronics and Information Systems, University of Ghent, St. Pietersnieuwstraat 41, B-9000 Ghent, Belgium (Belgium)

    1994-12-31

    In Positron Emission Tomography (PET) images have to be reconstructed from moisy projection data. The noise on the PET data can be modeled by a Poison distribution. In this paper, we present the results of using the simulated annealing technique to reconstruct PET images. Various parameter settings of the simulated annealing algorithm are discussed and optimized. The reconstructed images are of good quality and high contrast, in comparison to other reconstruction techniques. (authors). 11 refs., 2 figs.

  1. Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography in Disseminated Cryptococcosis

    Science.gov (United States)

    Tripathy, Sarthak; Parida, Girish Kumar; Roy, Shambo Guha; Singhal, Abhinav; Mallick, Saumya Ranjan; Tripathi, Madhavi; Shamim, Shamim Ahmed

    2017-01-01

    Disseminated cryptococcosis without pulmonary involvement is a very rare phenomenon. Patterns of organ involvement in cryptococcosis resemble various other infective conditions as well as malignant conditions on fluorodeoxyglucose positron emission tomography–computed tomography. We present a case of a 43-year-old male patient who had disseminated cryptococcosis. The rarity of the case being noninvolvement of lungs and meninges and resembling more like lymphoma due to the diffuse involvement of the lymph nodes on both sides of the diaphragm. PMID:29142368

  2. Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Disseminated Cryptococcosis.

    Science.gov (United States)

    Tripathy, Sarthak; Parida, Girish Kumar; Roy, Shambo Guha; Singhal, Abhinav; Mallick, Saumya Ranjan; Tripathi, Madhavi; Shamim, Shamim Ahmed

    2017-01-01

    Disseminated cryptococcosis without pulmonary involvement is a very rare phenomenon. Patterns of organ involvement in cryptococcosis resemble various other infective conditions as well as malignant conditions on fluorodeoxyglucose positron emission tomography-computed tomography. We present a case of a 43-year-old male patient who had disseminated cryptococcosis. The rarity of the case being noninvolvement of lungs and meninges and resembling more like lymphoma due to the diffuse involvement of the lymph nodes on both sides of the diaphragm.

  3. Measurement of brain pH with positron emission tomography

    International Nuclear Information System (INIS)

    Buxton, R.B.; Alpert, N.M.; Ackerman, R.H.; Wechsler, L.R.; Elmaleh, D.R.; Correia, J.A.

    1985-01-01

    With positron emission tomography (PET) it is now possible to measure local brain pH noninvasively in humans. The application of PET to the determination of pH is relatively new, so only a handful of papers on the subject have appeared in print. This chapter reviews the current strategies for measuring brain pH with PET, discuss methodological problems, and present initial results

  4. Simulated annealing image reconstruction for positron emission tomography

    International Nuclear Information System (INIS)

    Sundermann, E.; Lemahieu, I.; Desmedt, P.

    1994-01-01

    In Positron Emission Tomography (PET) images have to be reconstructed from moisy projection data. The noise on the PET data can be modeled by a Poison distribution. In this paper, we present the results of using the simulated annealing technique to reconstruct PET images. Various parameter settings of the simulated annealing algorithm are discussed and optimized. The reconstructed images are of good quality and high contrast, in comparison to other reconstruction techniques. (authors)

  5. High-resolution simulation of link-level vehicle emissions and concentrations for air pollutants in a traffic-populated eastern Asian city

    Directory of Open Access Journals (Sweden)

    S. Zhang

    2016-08-01

    Full Text Available Vehicle emissions containing air pollutants created substantial environmental impacts on air quality for many traffic-populated cities in eastern Asia. A high-resolution emission inventory is a useful tool compared with traditional tools (e.g. registration data-based approach to accurately evaluate real-world traffic dynamics and their environmental burden. In this study, Macau, one of the most populated cities in the world, is selected to demonstrate a high-resolution simulation of vehicular emissions and their contribution to air pollutant concentrations by coupling multimodels. First, traffic volumes by vehicle category on 47 typical roads were investigated during weekdays in 2010 and further applied in a networking demand simulation with the TransCAD model to establish hourly profiles of link-level vehicle counts. Local vehicle driving speed and vehicle age distribution data were also collected in Macau. Second, based on a localized vehicle emission model (e.g. the emission factor model for the Beijing vehicle fleet – Macau, EMBEV–Macau, this study established a link-based vehicle emission inventory in Macau with high resolution meshed in a temporal and spatial framework. Furthermore, we employed the AERMOD (AMS/EPA Regulatory Model model to map concentrations of CO and primary PM2.5 contributed by local vehicle emissions during weekdays in November 2010. This study has discerned the strong impact of traffic flow dynamics on the temporal and spatial patterns of vehicle emissions, such as a geographic discrepancy of spatial allocation up to 26 % between THC and PM2.5 emissions owing to spatially heterogeneous vehicle-use intensity between motorcycles and diesel fleets. We also identified that the estimated CO2 emissions from gasoline vehicles agreed well with the statistical fuel consumption in Macau. Therefore, this paper provides a case study and a solid framework for developing high-resolution environment assessment tools for other

  6. Positron emission tomography in the evaluation of subdural hematomas

    International Nuclear Information System (INIS)

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

    1980-01-01

    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 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

  7. Attenuation Correction Strategies for Positron Emission Tomography/Computed Tomography and 4-Dimensional Positron Emission Tomography/Computed Tomography

    OpenAIRE

    Pan, Tinsu; Zaidi, Habib

    2013-01-01

    This article discusses attenuation correction strategies in positron emission tomography/computed tomography (PET/CT) and 4 dimensional PET/CT imaging. Average CT scan derived from averaging the high temporal resolution CT images is effective in improving the registration of the CT and the PET images and quantification of the PET data. It underscores list mode data acquisition in 4 dimensional PET and introduces 4 dimensional CT popular in thoracic treatment planning to 4 dimensional PET/CT. ...

  8. Comparison of Diagnostic Performance of Three-Dimensional Positron Emission Mammography versus Whole Body Positron Emission Tomography in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Dong Dai

    2017-01-01

    Full Text Available Objective. To compare the diagnostic performance of three-dimensional (3D positron emission mammography (PEM versus whole body positron emission tomography (WBPET for breast cancer. Methods. A total of 410 women with normal breast or benign or highly suspicious malignant tumors were randomized at 1 : 1 ratio to undergo 3D-PEM followed by WBPET or WBPET followed by 3D-PEM. Lumpectomy or mastectomy was performed on eligible participants after the scanning. Results. The sensitivity and specificity of 3D-PEM were 92.8% and 54.5%, respectively. WBPET showed a sensitivity of 95.7% and specificity of 56.8%. After exclusion of the patients with lesions beyond the detecting range of the 3D-PEM instrument, 3D-PEM showed higher sensitivity than WBPET (97.0% versus 95.5%, P = 0.913, particularly for small lesions (<1 cm (72.0% versus 60.0%, P = 0.685. Conclusions. The 3D-PEM appears more sensitive to small lesions than WBPET but may fail to detect lesions that are beyond the detecting range. This study was approved by the Ethics Committee (E2012052 at the Tianjin Medical University Cancer Institute and Hospital (Tianjin, China. The instrument positron emission mammography (PEMi was approved by China State Food and Drug Administration under the registration number 20153331166.

  9. Positron emission tomography and cerebral metabolism

    International Nuclear Information System (INIS)

    Comar, D.; Maziere, M.; Zarifian, E.; Naquet, R.

    1979-01-01

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

  10. Positron transaxial emission tomograph with computerized image reconstruction

    International Nuclear Information System (INIS)

    Jatteau, Michel.

    1981-01-01

    This invention concerns a positron transaxial emission tomography apparatus with computerized image reconstruction, like those used in nuclear medicine for studying the metabolism of organs, in physiological examinations and as a diagnosis aid. The operation is based on the principle of the detection of photons emitted when the positrons are annihilated by impact with an electron. The appliance is mainly composed of: (a) - a set of gamma ray detectors distributed on a polygonal arrangement around the body area to be examined, (b) - circuits for amplifying the signals delivered by the gamma ray detectors, (c) - computers essentially comprising energy integration and discrimination circuits and provided at the output of the detectors for calculating and delivering, as from the amplified signals, information on the position and energy relative to each occurrence constituted by the detections of photons, (d) - time coincidence circuits for selecting by emission of detector validation signals, only those occurrences, among the ensemble of those detected, which effectively result from the annihilation of positrons inside the area examined, (e) - a data processing system [fr

  11. First image from a combined positron emission tomography and field-cycled MRI system.

    Science.gov (United States)

    Bindseil, Geron A; Gilbert, Kyle M; Scholl, Timothy J; Handler, William B; Chronik, Blaine A

    2011-07-01

    Combining positron emission tomography and MRI modalities typically requires using either conventional MRI with a MR-compatible positron emission tomography system or a modified MR system with conventional positron emission tomography. A feature of field-cycled MRI is that all magnetic fields can be turned off rapidly, enabling the use of conventional positron emission tomography detectors based on photomultiplier tubes. In this demonstration, two photomultiplier tube-based positron emission tomography detectors were integrated with a field-cycled MRI system (0.3 T/4 MHz) by placing them into a 9-cm axial gap. A positron emission tomography-MRI phantom consisting of a triangular arrangement of positron-emitting point sources embedded in an onion was imaged in a repeating interleaved sequence of ∼1 sec MRI then 1 sec positron emission tomography. The first multimodality images from the combined positron emission tomography and field-cycled MRI system show no additional artifacts due to interaction between the systems and demonstrate the potential of this approach to combining positron emission tomography and MRI. Copyright © 2010 Wiley-Liss, Inc.

  12. Investigation of granular impact using positron emission particle tracking

    KAUST Repository

    Marston, Jeremy O.

    2015-04-01

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

  13. An automated blood sampling system used in positron emission tomography

    International Nuclear Information System (INIS)

    Eriksson, L.; Bohm, C.; Kesselberg, M.

    1988-01-01

    Fast dynamic function studies with positron emission tomography (PET), has the potential to give accurate information of physiological functions of the brain. This capability can be realised if the positron camera system accurately quantitates the tracer uptake in the brain with sufficiently high efficiency and in sufficiently short time intervals. However, in addition, the tracer concentration in blood, as a function of time, must be accurately determined. This paper describes and evaluates an automated blood sampling system. Two different detector units are compared. The use of the automated blood sampling system is demonstrated in studies of cerebral blood flow, in studies of the blood-brain barrier transfer of amino acids and of the cerebral oxygen consumption. 5 refs.; 7 figs

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

    International Nuclear Information System (INIS)

    Gould, K.L.

    1991-01-01

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

  15. Use of positron emission tomography in colorectal cancer

    International Nuclear Information System (INIS)

    Gonzalez E, Patricio; Jofre E, Josefina; Massardo V, Teresa; Humeres, Pamela; Canessa G, Jose; Sierralta C, Paulina

    2002-01-01

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

  16. Contribution of positron emission tomography in pleural disease.

    Science.gov (United States)

    Duysinx, B; Corhay, J-L; Larock, M-P; Withofs, N; Bury, T; Hustinx, R; Louis, R

    2010-10-01

    Positron emission tomography (PET) now plays a clear role in oncology, especially in chest tumours. We discuss the value of metabolic imaging in characterising pleural pathology in the light of our own experience and review the literature. PET is particularly useful in characterising malignant pleural pathologies and is a factor of prognosis in mesothelioma. Metabolic imaging also provides clinical information for staging lung cancer, in researching the primary tumour in metastatic pleurisy and in monitoring chronic or recurrent pleural pathologies. PET should therefore be considered as a useful tool in the diagnosis of liquid or solid pleural pathologies. Copyright © 2010 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  17. Positron emission tomography. Present status and Romanian perspectives

    International Nuclear Information System (INIS)

    Constantinescu, B.; Lungu, V.

    1995-01-01

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

  18. Design of a volume-imaging positron emission tomograph

    International Nuclear Information System (INIS)

    Harrop, R.; Rogers, J.G.; Coombes, G.H.; Wilkinson, N.A.; Pate, B.D.; Morrison, K.S.; Stazyk, M.; Dykstra, C.J.; Barney, J.S.; Atkins, M.S.; Doherty, P.W.; Saylor, D.P.

    1988-11-01

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

  19. Kinetic modeling in pre-clinical positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

  20. Time-of-Flight Positron Emission Tomography with Radiofrequency Phototube

    International Nuclear Information System (INIS)

    Margaryan, A.; Kakoyan, V.; Knyazyan, S.

    2011-01-01

    In this paper γ-detector, based on the radiofrequency (RF) phototube and recently developed fast and ultrafast scintillators, is considered for Time-of-Flight positron emission tomography applications. Timing characteristics of such a device has been investigated by means of a dedicated Monte Carlo code based on the single photon counting concept. Biexponential timing model for scintillators have been used. The calculations have shown that such a timing model is in a good agreement with recently measured data. The timing resolution of -detectors can be significantly improved by using the RF phototube. (authors)

  1. Low-resource synchronous coincidence processor for positron emission tomography

    International Nuclear Information System (INIS)

    Sportelli, Giancarlo; Belcari, Nicola; Guerra, Pedro; Santos, Andres

    2011-01-01

    We developed a new FPGA-based method for coincidence detection in positron emission tomography. The method requires low device resources and no specific peripherals in order to resolve coincident digital pulses within a time window of a few nanoseconds. This method has been validated with a low-end Xilinx Spartan-3E and provided coincidence resolutions lower than 6 ns. This resolution depends directly on the signal propagation properties of the target device and the maximum available clock frequency, therefore it is expected to improve considerably on higher-end FPGAs.

  2. Functional imaging of the brain with positron emission tomography

    International Nuclear Information System (INIS)

    Alavi, A.; Reivich, M.; Jones, S.C.; Greenberg, J.H.; Wolf, A.P.

    1982-01-01

    An extensive review, with 191 references, of the development and diagnostic use of positron emission tomography (PET) of the brain is presented. An historical overview of functional studies of the brain reviews the use of nitrons oxide, 85 Kr and 133 Xe, [ 14 C]2-deoxyglucose, and [ 18 F]FDG. The [ 18 F]FDG technique allows the investigation of the effects of physiologic stimulation on the brain. Several studies using this technique are reported. The effects of stroke, seizure disorders, aging and dementia, and schizophrenia on cerebral metabolism as demosntrated by PET are explored

  3. Characterization of metallic nanoparticles by high-resolution X-ray absorption and X-ray emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Timna-Josua

    2012-03-15

    In almost all areas of technology, metallic nanoparticles are of interest due to their special thermal, electronic, magnetic and optical properties. Their special properties are mainly due to their small size which implies the relevance of quantum effects as well as the significance of the surface: For 2 nm nanoparticles, the surface-to-volume ratio is already 1:1. However, the identification of surface-to-volume interactions - that are responsible for the new properties - is a difficult task due to the small size that inhibits a lot of 'standard' techniques to be applicable. Here X-ray absorption/emission spectroscopy (XAS/XES) is a favorable tool for the characterization of nanoparticles, independent on size, degree of crystallinity and shape/condition of the surface. Using XAS, a tempered nanosized Co{sub 3}Pt/C catalyst have been investigated. Its outstanding oxygen-reduction reaction (ORR) properties in a fuel cell could be related to a lowered Pt 5d-band center connected to a tightened Pt-Pt bonding distance, leading to a weakening of the oxygen adsorption strength so that the ORR may proceed faster. One drawback remains, however, as the properties found by (standard) XAS are summed up for different chemical environments of the chosen element. Thus, no distinction can be made between, e.g., the pure metal in a nanoparticles' interior and the ligated metal in the outer shells or surface. Here, high-resolution fluorescence-detected XAS (HRFD-XAS) provides additional opportunities as, due to its chemical sensitivity, it leads to site-selective XAS. For a system of 6 nm sized Co nanoparticles, build up of a metallic core surrounded by a protecting shell, that resulted from the 'smooth oxidation' process, this technique of site-selective XAS was proven to be applicable. For the first time, the interior and outer shell of a metallic nanoparticle could be characterized separately. In particular, the Co-hcp phase could be determined for the

  4. Application of positron emission tomography in industrial research

    International Nuclear Information System (INIS)

    Jonkers, G.; van den Bergen, E.A.; Vonkeman, K.A.

    1990-01-01

    Positron Emission computed Tomography (PET) is a relatively new imaging technique, exploiting the 511 keV annihilation radiation characteristic of positron emitters. Although exclusively used till now in the field of nuclear medicine, the application of PET for the non-invasive, in-situ visualisation of processes of industrial interest is challenging, because PET can in principle be used to obtain quantitative, 2D/3D images of the flow and distribution of fluids inside process units, whose steel walls may be up to several centimeters thick. With the aid of a NeuroECAT positron tomographer the PET technique has been utilised to image important (model) processes in the petrochemical industry, using physical labelling of the phase to be imaged. First, the displacement of a brine/surfactant phase, labelled with 66 Ga-EDTA, in a piece of reservoir rock was imaged. Secondly, the dehydration of water-in-oil emulsions was monitored dynamically by labelling the water phase with 68 Ga-EDTA. The second study in particular demonstrates that in the presence of noisy data the image reconstruction method utilised strongly influences the results obtained. With the advent of PET in nuclear medicine the availability of short-lived positron emitting nuclides like 11 C (t1/2 = 20 min), 13 N (t1/2 = 10 min) and 15 0 (t1/2 = 2 min) has increased considerably, allowing the investigation of industrially important reactions by chemical labelling. Utilising the NeuroECAT in a special mode, the catalytic oxidation of carbon monoxide could be imaged in a model tubular reactor by using 11 C-labelled CO, providing information about the kinetics of the individual reaction steps and interactions and about the degree of occupation of catalytically active sites. (author)

  5. High resolution positron Q-value measurements and nuclear structure studies far from the stability line. Progress report, July 1, 1979-June 30, 1980

    International Nuclear Information System (INIS)

    Avignone, F.T. III.

    1980-01-01

    This document represents a progress report and renewal proposal for the contract DEAS 09 79 ER10434 between the USDOE and USC. During the time from 1 July 1979 to 1 March 1980, the large 35% intrinsic Ge detector was purchased and tested, and the new hyperpure Ge detector for positron end-point-energy measurements was designed and fabricated by ORTEC. It was delivered just prior to January 1, 1980. Measurements using this special equipment began in January 1980. During this period, a new effort in the measurement of short nuclear lifetimes was completed, and nuclear structure measurements of 206 Rn nd 208 Rn were completed. The results of these efforts are described in the text. A search for the Post Doctoral Research Associate was started last summer and the position will be filled on or about 1 March 1980. The first experiments to measure positron end-point-energies were proposed to the ORIC scheduling committee, and measurements will begin in March 1980. Theoretical efforts describe accurately the interference of annihilation radiation with positron end-point-energy measurements were begun

  6. Positron emission CT on post-traumatic epilepsy

    International Nuclear Information System (INIS)

    Tsukiyama, Takashi; Tsubokawa, Takashi; Doi, Nobuyasu; Sato, Kohten; Iio, Masaaki.

    1983-01-01

    Six patients suffering from post-traumatic epilepsy were checked by encephalography (EEG), X-ray CT and cerebral positron emission computed tomography (PECT) using 11 C-carbon dioxide ( 11 CO 2 ) and 11 C-glucoses as indicators of the local cerebral circulation and local cerebral glucose utilization, in order to assess the diagnostic value of PECT in post-traumatic epilepsy. In those patients (4 cases) who had focal electrical abnormalities or X-ray CT lesions, PECT clearly revealed localized regions of decreased cerebral circulation and glucose utilization. A focal hypometabolic zone also appeared in the post-traumatic epilepsy (1 case) which had a normal X-ray CT. One case, who had been treated for several years by medication but showed no EEG change and no abnormality on X-ray CT, revealed a normal circulation and metabolism by RECT. This case did not require any further medication for epilepsy. It is concluded that positron emission CT represents a useful diagnostic method for post-traumatic epilepsy which does not demonstrate any abnormality on X-ray CT. (author)

  7. Clinical applications of positron emission tomography in breast cancer patients

    International Nuclear Information System (INIS)

    Roemer, W.; Avril, N.; Schwaiger, M.

    1997-01-01

    Increased glucose metabolism by malignant tissue can be visualized with positron emission tomography (PET), using the radiolabeled glucose analogue F-18 fluorodeoxyglucose (FDG). Depending on the criteria of image interpretation FDG-PET allows detection of breast cancer with a sensitivity of 68% to 94 % and a specificity of 84 % to 97 %. However, sensitivity to visualize small tumors (< 1 cm) is limited. Positron emission tomography demonstrates tumor involvement of regional lymph nodes with high accuracy, predominantly in patients with advanced breast cancer. The sensitivity for the detection of axillary lymph node metastases was 79% with a corresponding specificity of 96 %. Lymph node metastases could not be identified in four of six patients with small primary breast cancer (stage pT1), resulting in a sensitivity of only 33% in these patients. By visualizing primary tumors and metastases in one imaging procedure, PET imaging may allow the effective staging of breast cancer patients. Further studies are needed to define the role of scintigraphic techniques for the diagnostic work-up in patients. (author)

  8. Positron Emission Tomography imaging with the SmartPET system

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.J. [Department of Physics, University of Liverpool, Liverpool, Merseyside L69 7ZE (United Kingdom)], E-mail: cooperrj@ornl.gov; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Grint, A.N.; Harkness, L.J.; Nolan, P.J.; Oxley, D.C.; Scraggs, D.P.; Mather, A.R. [Department of Physics, University of Liverpool, Liverpool, Merseyside L69 7ZE (United Kingdom); Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom)

    2009-07-21

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

  9. Positron emission tomography in the management of cervix cancer patients

    International Nuclear Information System (INIS)

    Bonardel, G.; Gontier, E.; Soret, M.; Dechaud, C.; Fayolle, M.; Foehrenbach, H.; Chargari, C.; Bauduceau, O.

    2009-01-01

    Since its introduction in clinical practice in the 1990 s, positron emission tomography (PET), usually with 18 F-fluoro-2-deoxy-D-glucose ( 18 F-F.D.G.), has become an important imaging modality in patients with cancer. For cervix carcinoma, F.D.G.-PET is significantly more accurate than computed tomography (CT) and is recommended for loco-regional lymph node and extra pelvic staging. The metabolic dimension of the technique provides additional prognostic information. Ongoing studies now concentrate on more advanced clinical applications, such as the planning of radiotherapy, the response evaluation after the induction of therapy, the early detection of recurrence. Technical innovations, such as PET cameras with better spatial resolution and hybrid positron emission tomography/computed tomography (PET-CT), available now on the whole territory, provide both anatomic and metabolic information in the same procedure. From the point of view of biological metabolism, new radiopharmaceutical probes are being developed. Those hold promise for future refinements in this field. This article reviews the current applications of F.D.G.-PET in patients with cervix cancer. (authors)

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

    International Nuclear Information System (INIS)

    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 userfriendly analysis workstations permits installation of a clinical PET center within most nuclear medicine facilities. This review provides simple descriptions of important aspects concerning physics, instrumentation, and image analysis in PET imaging which should be understood by medical personnel involved in the clinical operation of a PET imaging center. (author)

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

    International Nuclear Information System (INIS)

    Standke, R.

    2002-01-01

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

  12. Characterization of primary organic aerosol emissions from meat cooking, trash burning, and motor vehicles with high-resolution aerosol mass spectrometry and comparison with ambient and chamber observations.

    Science.gov (United States)

    Mohr, Claudia; Huffman, Alex; Cubison, Michael J; Aiken, Allison C; Docherty, Kenneth S; Kimmel, Joel R; Ulbrich, Ingrid M; Hannigan, Michael; Jimenez, Jose L

    2009-04-01

    Organic aerosol (OA) emissions from motor vehicles, meat-cooking and trash burning are analyzed here using a high-resolution aerosol mass spectrometer (AMS). High resolution data show that aerosols emitted by combustion engines and plastic burning are dominated by hydrocarbon-like organic compounds. Meat cooking and especially paper burning emissions contain significant fractions of oxygenated organic compounds; however, their unit-resolution mass spectral signatures are very similar to those from ambient hydrocarbon-like OA, and very different from the mass spectra of ambient secondary or oxygenated OA (OOA). Thus, primary OA from these sources is unlikelyto be a significant direct source of ambient OOA. There are significant differences in high-resolution tracer m/zs that may be useful for differentiating some of these sources. Unlike in most ambient spectra, all of these sources have low total m/z 44 and this signal is not dominated by the CO2+ ion. All sources have high m/z 57, which is low during high OOA ambient periods. Spectra from paper burning are similar to some types of biomass burning OA, with elevated m/z 60. Meat cooking aerosols also have slightly elevated m/z 60, whereas motor vehicle emissions have very low signal at this m/z.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gillard, W

    2008-01-15

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

  14. Spatiotemporal variability of biogenic terpenoid emissions in Pearl River Delta, China, with high-resolution land-cover and meteorological data

    Science.gov (United States)

    Wang, Xuemei; Situ, Shuping; Guenther, Alex; Chen, Fei; Wu, Zhiyong; Xia, Beicheng; Wang, Tijian

    2011-04-01

    This study intended to provide 4-km gridded, hourly, year-long, regional estimates of terpenoid emissions in the Pearl River Delta (PRD), China. It combined Thematic Mapper images and local-survey data to characterize plant functional types, and used observed emission potential of biogenic volatile organic compounds (BVOC) from local plant species and high-resolution meteorological outputs from the MM5 model to constrain the MEGAN BVOC-emission model. The estimated annual emissions for isoprene, monoterpene and sesquiterpene are 95.55 × 106 kg C, 117.35 × 106 kg C and 9.77 × 106 kg C, respectively. The results show strong variabilities of terpenoid emissions spanning diurnal and seasonal time scales, which are mainly distributed in the remote areas (with more vegetation and less economic development) in PRD. Using MODIS PFTs data reduced terpenoid emissions by 27% in remote areas. Using MEGAN-model default emission factors led to a 24% increase in BVOC emission. The model errors of temperature and radiation in MM5 output were used to assess impacts of uncertainties in meteorological forcing on emissions: increasing (decreasing) temperature and downward shortwave radiation produces more (less) terpenoid emissions for July and January. Strong temporal variability of terpenoid emissions leads to enhanced ozone formation during midday in rural areas where the anthropogenic VOC emissions are limited.

  15. 77 FR 71802 - Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Science.gov (United States)

    2012-12-04

    ... Positron Emission Tomography (PET) Drugs.'' The guidance is intended to assist manufacturers of PET drugs... one self-addressed adhesive label to assist that office in processing your requests. See the... ``Investigational New Drug Applications for Positron Emission Tomography (PET) Drugs.'' The guidance summarizes the...

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

    International Nuclear Information System (INIS)

    Lavayssiere, Robert; Cabee, Anne-Elizabeth; Filmont, Jean-Emmanuel

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-15

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

  18. A regional high-resolution emission inventory of primary air pollutants in 2012 for Beijing and the surrounding five provinces of North China

    Science.gov (United States)

    Liu, Huanjia; Wu, Bobo; Liu, Shuhan; Shao, Panyang; Liu, Xiangyang; Zhu, Chuanyong; Wang, Yong; Wu, Yiming; Xue, Yifeng; Gao, Jiajia; Hao, Yan; Tian, Hezhong

    2018-05-01

    A high resolution regional emission inventory of typical primary air pollutants (PAPs) for the year 2012 in Beijing and the surrounding five provinces (BSFP) of North China is developed. It is compiled with the combination of bottom-up and top-down methods, based on city-level collected activity data and the latest updated specific emission factors for different sources. The considered sources are classified into 12 major categories and totally 36 subcategories with respect to their multi-dimensional characteristics, such as economic sector, combustion facility or industrial process, installed air pollution control devices, etc. Power plant sector is the dominant contributor of NOX emissions with an average contribution of 34.1%, while VOCs emissions are largely emitted from industrial process sources (33.9%). Whereas, other stationary combustion sources represent major sources of primary PM2.5, PM10 and BC emissions, accounting for 22.7%, 30.0% and 33.9% of the total emissions, respectively. Hebei province contributes over 34% of the regional total CO emissions because of huge volume of iron and steel production. By comparison, Shandong province ranks as the biggest contributor for NOX, PM10, PM2.5, SO2, VOCs and OC. Further, the BSFP regional total emissions are spatially distributed into grid cells with a high resolution of 9 km × 9 km using GIS tools and surrogate indexes, such regional population, gross domestic product (GDP) and the types of arable soils. The highest emission intensities are mainly located in Beijing-Tianjin-Tangshan area, Jinan-Laiwu-Zibo area and several other cities such as Shijiazhuang, Handan, and Zhengzhou. Furthermore, in order to establish a simple method to estimate and forecast PAPs emissions with macroscopic provincial-level statistical parameters in China, multi-parameter regression equations are firstly developed to estimate emissions outside the BSFP region with routine statistics (e.g. population, total final coal consumption

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

    International Nuclear Information System (INIS)

    Buck, A.; Kamel, E.

    2002-01-01

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

  20. 4.5 Tesla magnetic field reduces range of high-energy positrons -- Potential implications for positron emission tomography

    International Nuclear Information System (INIS)

    Wirrwar, A.; Vosberg, H.; Herzog, H.; Halling, H.; Weber, S.; Mueller-Gaertner, H.W.; Forschungszentrum Juelich GmbH

    1997-01-01

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

  1. Analysis of human cerebral functions using positron emission tomography (PET)

    International Nuclear Information System (INIS)

    Shibasaki, Takashi

    1984-01-01

    Positron emission tomography has two major advantages to analyse human cerebral functions in vivo. First, we can see the distribution of a variety of substance in the living (and doing something) human brain. Positron emitters, 11 C, 13 N, 15 O and 18 F, are made by medical cyclotron and are elements of natural substrates or easily tagged to substrate. Second, the distribution of the tracer is calculated to make a quantitative functional map in a reasonable spatial resolution over the entire brain in the same time. Not only cortical areas but also deeper structures show regional cerebral blood flow (rCBF) or local cerebral metabolic rates (LCMRs). Nowadays, PET is put to practical use for determination of mainly rCBF, LCMR for glucose (LCMRsub(glu)), LCMR for oxygen (LCMRsub(o2)) and regional cerebral blood volume (rCBV). There have been many other pilot studies, such as estimation of distribution of given neurotransmitters or modulators in the brain which also confirms the substances' role in the neuronal function, and observation of protein synthesis relating to memory function. (J.P.N.)

  2. Application of positron emission tomography in the lung

    International Nuclear Information System (INIS)

    Valind, S.O.; Wollmer, P.E.; Rhodes, C.G.

    1985-01-01

    The early application of positron emission tomography in the lung was mainly concerned with the investigation of the regional volume of the vascular and extravascular compartments, using measurements of fractional blood volume and lung density. However, in addition to its passive role in the exchange of oxygen and carbon dioxide, the lung exerts a number of active, metabolic functions such as the inactivation of circulating vasoactive compounds and the synthesis and release of biologically active substances. Furthermore, many of the pulmonary disorders originate at a cellular or metabolic level, or have metabolic consequences. Many of the substrates of biochemical reactions and the biologically active compounds, or their analogs, can be labeled with positron-emitting radioisotopes without disturbing their biological or biochemical characteristics. In combination with the development of the appropriate physiological and biochemical models, the quantitative measurements possible with PET provide a unique opportunity of regionally studying the metabolic processes of the lung of man in vivo. Hence, a range of different expressions of metabolism and of lung function can be evaluated and their interdependence can be studied regionally

  3. Evaluation of scintillators and semiconductor detectors to image three-photon positron annihilation for positron emission tomography

    International Nuclear Information System (INIS)

    Abuelhia, E.; Spyrou, N.M.; Kacperski, K.; College University, Middlesex Hospital, London

    2008-01-01

    Positron emission tomography (PET) is rapidly becoming the main nuclear imaging modality of the present century. The future of PET instrumentation relies on semiconductor detectors because of their excellent characteristics. Three-photon positron annihilation has been recently investigated as a novel imaging modality, which demands the crucial high energy resolution of semiconductor detector. In this work the evaluation of the NaI(Tl) scintillator and HPGe and CdZTe semiconductor detectors, to construct a simple three-photon positron annihilation scanner has been explored. The effect of detector and scanner size on spatial resolution (FWHM) is discussed. The characteristics: energy resolution versus count rate and point-spread function of the three-photon positron annihilation image profile from triple coincidence measurements were investigated. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Metter, E.J.; Hanson, W.R.; Jackson, C.A.; Kempler, D.; van Lancker, D.; Mazziotta, J.C.; Phelps, M.E. (National Institute of Aging, Baltimore, MD (USA))

    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.

  5. Evaluation of brain tumours by positron emission tomography

    International Nuclear Information System (INIS)

    Schober, O.; Meyer, G.J.

    1992-01-01

    The clinical application of positron emission tomography (PET) for the evaluation of brain tumours has proved clinically valuable. Amino acid and FDG-glucose PET provide information on the degree of malignancy and the prognosis during the initial evaluation. After therapy, the residual tumour can be visualized and recurrence can be differentiated from necrosis. Amino acids have advantages over FDG for these clinical applications. Blood flow, oxygen extraction and metabolism and blood-brain barrier permeability are of minor relevance in clinical situations. Comparison of PET with MRI and MRS will provide new data. The quantitative information of the unique information yielded by PET will lead to a more important clinical role, as will the extrapolation of this experience to the SPECT technique. (orig.) [de

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

    International Nuclear Information System (INIS)

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

    1990-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-10-01

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

  8. Diagnosis and evaluation of gastric cancer by positron emission tomography

    Science.gov (United States)

    Wu, Chen-Xi; Zhu, Zhao-Hui

    2014-01-01

    Gastric cancer is the second leading cause of cancer mortality worldwide. The diagnosis of gastric cancer has been significantly improved with the broad availability of gastrointestinal endoscopy. Effective technologies for accurate staging and quantitative evaluation are still in demand to merit reasonable treatment and better prognosis for the patients presented with advanced disease. Preoperative staging using conventional imaging tools, such as computed tomography (CT) and endoscopic ultrasonography, is inadequate. Positron emission tomography (PET), using 18F-fluorodeoxyglucose (FDG) as a tracer and integrating CT for anatomic localization, holds a promise to detect unsuspected metastasis and has been extensively used in a variety of malignancies. However, the value of FDG PET/CT in diagnosis and evaluation of gastric cancer is still controversial. This article reviews the current literature in diagnosis, staging, response evaluation, and relapse monitoring of gastric cancer, and discusses the current understanding, improvement, and future prospects in this area. PMID:24782610

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

    International Nuclear Information System (INIS)

    Pizzichemi, M.

    2016-01-01

    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.

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

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  11. Positron emission tomography with gamma camera in coincidence mode

    International Nuclear Information System (INIS)

    Hertel, A.; Hoer, G.

    1999-01-01

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

  12. Development of the LBNL positron emission mammography camera

    International Nuclear Information System (INIS)

    Huber, Jennifer S.; Choong, Woon-Seng; Wang, Jimmy; Maltz, Jonathon S.; Qi, Jinyi; Mandelli, Emanuele; Moses, William W.

    2002-01-01

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

  13. Positron emission tomography (PET) for oncologic applications in oral region

    International Nuclear Information System (INIS)

    Shozushima, Masanori; Terasaki, Kazunori

    2004-01-01

    A rapidly emerging clinical application of positron emission tomography (PET) is the detection of cancer with radionuclide tracer, because it provides information unavailable by ultrasound, computed tomography or magnetic resonance imaging. The most commonly used radiotracer for PET oncologic imaging is fluorine-18-labeled fluorodeoxyglucose ( 18 F-FDG). Early studies show PET has potential value in viewing the region of the tumor, detecting, staging, grading, monitoring response to anticancer therapy, and differentiating recurrent or residual disease from post treatment changes. However, limitations of FDG-PET in the head and neck region, namely, physiological FDG uptake in the salivary glands and palatine tonsils, have been reported, increasing the false-positive rates in image interpretation. This review was designed to address these distinctions of oral cancer PET imaging: specialization of PET equipment, cancer cell metabolism, proliferation and tracers, clinical diagnosis of oral cancer with PET, pitfalls in oncologic diagnosis with FDG-PET imaging. (author)

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

    International Nuclear Information System (INIS)

    Brard, Emmanuel

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    H. Nagasawa

    1993-01-01

    Full Text Available We measured cerebral blood flow, oxygen metabolism, glucose utilization, and dopamine metabolism in the brain of a patient with corticobasal degeneration using positron emission tomography (PET. The clinical picture is distinctive, comprising features referable to both cortical and basal ganglionic dysfunction. Brain imagings of glucose and dopamine metabolism can demonstrate greater abnormalities in the cerebral cortex and in the striatum contralateral to the more affected side than those of blood flow and oxygen metabolism. This unique combination study measuring both cerebral glucose utilization and dopamine metabolism in the nigrostriatal system can provide efficient information about the dysfunctions which are correlated with individual clinical symptoms, and this study is essential to diagnosis of corticobasal degeneration.

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

    International Nuclear Information System (INIS)

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

    1987-01-01

    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

  17. Lesion detection and quantitation of positron emission mammography

    International Nuclear Information System (INIS)

    Qi, Jinyi; Huesman, Ronald H.

    2001-01-01

    A Positron Emission Mammography (PEM) scanner dedicated to breast imaging is being developed at our laboratory. We have developed a list mode likelihood reconstruction algorithm for this scanner. Here we theoretically study the lesion detection and quantitation. The lesion detectability is studied theoretically using computer observers. We found that for the zero-order quadratic prior, the region of interest observer can achieve the performance of the prewhitening observer with a properly selected smoothing parameter. We also study the lesion quantitation using the test statistic of the region of interest observer. The theoretical expressions for the bias, variance, and ensemble mean squared error of the quantitation are derived. Computer simulations show that the theoretical predictions are in good agreement with the Monte Carlo results for both lesion detection and quantitation

  18. Evaluating patients with ischemic cerebrovascular disease using positron emission tomography

    International Nuclear Information System (INIS)

    Raichle, M.E.

    1982-01-01

    Recent advances in nuclear medicine imaging techniques offer an important alternative for the evaluation of therapy for ischemic cerebrovascular disease. In particular, positron emission tomography (PET), with its capacity to provide quantitative measurements of brain blood flow, metabolism and biochemistry on a truly regional basis, now offers the opportunity to evaluate therapy in terms of specific changes in these parameters. By doing this PET permits one to study the problem on an individual patient basis with each subject serving as his own control. The author has been pursuing this approach in patients considered candidates for superficial temporal artery-middle cerebral artery anastomosis to bypass major stenotic or occlusive lesions of the internal carotid or middle cerebral artery. The results indicate that PET is of considerable value in establishing much more exactly the pathophysiology of certain forms of ischemic cerebrovascular disease and evaluating a form of therapy designed to correct the basic underlying defect. (Auth./C.F.)

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

    International Nuclear Information System (INIS)

    Alexoff, D.L.

    1991-01-01

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

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

    International Nuclear Information System (INIS)

    Naagren, Kjell; Halldin, Christer; Rinne, Juha O.

    2010-01-01

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

  1. Data acquisition electronics for positron emission mammography (PEM) detectors

    International Nuclear Information System (INIS)

    Martinez, J.D.; Sebastia, A.; Cerda, J.; Esteve, R.; Mora, F.J.; Toledo, J.F.; Benlloch, J.M.; Gimenez, N.; Gimenez, M.; Lerche, Ch. W.; Pavon, N.; Sanchez, F.

    2005-01-01

    Positron emission mammography (PEM) is an innovative technique to increase sensitivity and overcome the main drawbacks of conventional X-ray screening. However, dedicated PET imaging systems demand specific hardware solutions for data acquisition and processing that can take advantage of the reduction in the number of channels. Data acquisition issues can affect PEM scanners performance and they should be exhaustively addressed in order to exploit the increment in the event count rate. This is crucial in order to reduce both the scanning time and the total injected dose. This paper presents the electronics for our PEM camera prototype that enables us to achieve very high-count rates and perform comprehensive online processing. Results about acquisition in our detector for a typical clinical setup are studied using Monte Carlo simulation of hot lesion phantoms

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

    Science.gov (United States)

    Raine, A; Buchsbaum, M; LaCasse, L

    1997-09-15

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

  3. Investigation of language lateralization mechanism by Positron Emission Tomography

    International Nuclear Information System (INIS)

    Belin, Pascal

    1997-01-01

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

  4. F-18-fluorodeoxyglucose-positron-emission tomography in neurology

    International Nuclear Information System (INIS)

    Fazekas, F.; Payer, F.

    2002-01-01

    Positron emission tomography using F-18-fluorodeoxyglucose (F-18-FDG-PET) is an ideal tool for imaging regional cerebral metabolism as glucose is the most important source of energy for neurons. Under physiologic conditions the pattern of metabolism reflects the state of cerebral activation which can be modulated by various stimuli to investigate cerebral organization. Pathologic conditions usually cause a drop in metabolism because of neuronal inactivity or loss. They can, however, also be associated with an increased rate of glucose metabolism such as in case of active epileptic foci or malignant tumors. As a consequence F-18-FDG-PET has become a valuable functional imaging modality especially for the diagnostic clarification of non-contributory or negative morphologic imaging results. Dementia, pre-surgical evaluation of epilepsy and neurooncology are currently frequent indications for referral to F-18-FDG-PET in neurology. (author)

  5. A simulation study of a method to reduce positron annihilation spread distributions using a strong magnetic field in positron emission tomography

    International Nuclear Information System (INIS)

    Iida, H.; Kanno, I.; Miura, S.; Murakami, M.; Takahashi, V.; Kemura, K.

    1986-01-01

    The positron trajectories have been three-dimensionally simulated using a Monte-Carlo method under various strength of the magnetic field. More than 5 tesla of the field confined the positrons effectively, resulting in increase of the probability of the annihilation within a limited small region, hence the higher spatial resolution in positron emission tomography

  6. 76 FR 6143 - Draft Guidance on Positron Emission Tomography Drug Applications-Content and Format for New Drug...

    Science.gov (United States)

    2011-02-03

    ...; formerly Docket No. 00D-0892] Draft Guidance on Positron Emission Tomography Drug Applications--Content and... Applications for Certain Positron Emission Tomography Drug Products; Availability,'' issued on March 10, 2000... and ANDAs.'' The draft guidance is intended to assist manufacturers of certain positron emission...

  7. Dynamic high resolution imaging of rats

    International Nuclear Information System (INIS)

    Miyaoka, R.S.; Lewellen, T.K.; Bice, A.N.

    1990-01-01

    A positron emission tomography with the sensitivity and resolution to do dynamic imaging of rats would be an invaluable tool for biological researchers. In this paper, the authors determine the biological criteria for dynamic positron emission imaging of rats. To be useful, 3 mm isotropic resolution and 2-3 second time binning were necessary characteristics for such a dedicated tomograph. A single plane in which two objects of interest could be imaged simultaneously was considered acceptable. Multi-layered detector designs were evaluated as a possible solution to the dynamic imaging and high resolution imaging requirements. The University of Washington photon history generator was used to generate data to investigate a tomograph's sensitivity to true, scattered and random coincidences for varying detector ring diameters. Intrinsic spatial uniformity advantages of multi-layered detector designs over conventional detector designs were investigated using a Monte Carlo program. As a result, a modular three layered detector prototype is being developed. A module will consist of a layer of five 3.5 mm wide crystals and two layers of six 2.5 mm wide crystals. The authors believe adequate sampling can be achieved with a stationary detector system using these modules. Economical crystal decoding strategies have been investigated and simulations have been run to investigate optimum light channeling methods for block decoding strategies. An analog block decoding method has been proposed and will be experimentally evaluated to determine whether it can provide the desired performance

  8. Application of high resolution X-ray emission spectroscopy on the study of Cr ion adsorption by activated carbon

    International Nuclear Information System (INIS)

    Espinoza-Quinones, Fernando R.; Modenes, Aparecido N.; Camera, Adriana S.; Stutz, Guillermo; Tirao, German; Palacio, Soraya M.; Kroumov, Alexander D.; Oliveira, Ana P.; Alflen, Vanessa L.

    2010-01-01

    In this work granular activated carbon has been chosen as an absorbent in order to investigate the Cr(VI) reduced by adsorption experiments. Several batch chromium-sorption experiments were carried out using 0.25 g of granular activated carbon in 50 mL aqueous solution containing approximately 70 and 140 mg L -1 of Cr(VI) and Cr(III), respectively. Cr-Kβ fluorescence spectra of Cr adsorbed in a carbon matrix and Cr reference materials were measured using a high-resolution Johann-type spectrometer. Based on evidence from the Cr-Kb satellite lines, the Cr(VI) reduction process has actually happened during metal adsorption by the activated carbon.

  9. High-resolution inventory of technologies, activities, and emissions of coal-fired power plants in China from 1990 to 2010

    Energy Technology Data Exchange (ETDEWEB)

    Liu, F.; Zheng, B.; He, K.B. [Tsinghua Univ., Beijing (China). State Key Joint Laboratory of Environment Simulation and Pollution Control; Zhang, Q. [Tsinghua Univ., Beijing (China). Ministry of Education Key Laboratory for Earth System Modeling; Tong, D.; Li, M. [Tsinghua Univ., Beijing (China). Ministry of Education Key Laboratory for Earth System Modeling; Tsinghua Univ., Beijing (China). State Key Joint Laboratory of Environment Simulation and Pollution Control; Huo, H. [Tsinghua Univ., Beijing (China). Inst. of Energy, Environment and Economy

    2015-07-01

    This paper, which focuses on emissions from China's coal-fired power plants during 1990-2010, is the second in a series of papers that aims to develop a high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20-year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335, and 442 % for SO{sub 2}, NO{sub x}, and CO{sub 2}, respectively, and decreased by 23 and 27 % for PM{sub 2.5} and PM{sub 10} respectively. Driven by the accelerated economic growth, large power plants were constructed throughout the country after 2000, resulting in a dramatic growth in emissions. The growth trend of emissions has been effectively curbed since 2005 due to strengthened emission control measures including the installation of flue gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of the power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination of temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

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

    International Nuclear Information System (INIS)

    Thompson, C.J.

    1992-01-01

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

  11. [Chilean experience with the use of 18F-deoxyglucose positron emission tomography].

    Science.gov (United States)

    Massardo, Teresa; Jofré, M Josefina; Sierralta, Paulina; Canessa, José; González, Patricio; Humeres, Pamela; Valdebenito, Robert

    2007-03-01

    Clinical oncology is the main application of 18F-deoxyglucose (FDG) positron emission tomography (PET). To evaluate the first 1,000 patients studied with FDG PET in Chile. Retrospective analysis of 1,000 patients (aged between 1 and 94 years, 550 females) studied with FDG PET, since 2003. All studies were performed in a high resolution Siemens Ecat-Exact HR (+). All reports were based on the visual analysis of three plane and three-dimensional images. Ninety seven percent of exams were done for oncological indications, mainly lung lesions, lymphoma, colorectal and gastroesophageal, cancer and breast tumors. Only 1% of patients had brain tumors. Non tumor neurological indications corresponded to 1.7%. Cardiac studies were only 0.3% and inflammatory process corresponded to 1%. The 5.6% corresponded to pediatric population. Six percent of patients were aged less than 18 years and in 50% of them, the indication was oncological, mainly lymphomas, brain tumors, endocrine cancers and sarcomas. The remaining 50% had a neurological indications, mainly for refractory epilepsy. PET FDG imaging was effective in the management of diverse diseases of children and adults.

  12. The Fire INventory from NCAR (FINN: a high resolution global model to estimate the emissions from open burning

    Directory of Open Access Journals (Sweden)

    C. Wiedinmyer

    2011-07-01

    Full Text Available The Fire INventory from NCAR version 1.0 (FINNv1 provides daily, 1 km resolution, global estimates of the trace gas and particle emissions from open burning of biomass, which includes wildfire, agricultural fires, and prescribed burning and does not include biofuel use and trash burning. Emission factors used in the calculations have been updated with recent data, particularly for the non-methane organic compounds (NMOC. The resulting global annual NMOC emission estimates are as much as a factor of 5 greater than some prior estimates. Chemical speciation profiles, necessary to allocate the total NMOC emission estimates to lumped species for use by chemical transport models, are provided for three widely used chemical mechanisms: SAPRC99, GEOS-CHEM, and MOZART-4. Using these profiles, FINNv1 also provides global estimates of key organic compounds, including formaldehyde and methanol. Uncertainties in the emissions estimates arise from several of the method steps. The use of fire hot spots, assumed area burned, land cover maps, biomass consumption estimates, and emission factors all introduce error into the model estimates. The uncertainty in the FINNv1 emission estimates are about a factor of two; but, the global estimates agree reasonably well with other global inventories of biomass burning emissions for CO, CO2, and other species with less variable emission factors. FINNv1 emission estimates have been developed specifically for modeling atmospheric chemistry and air quality in a consistent framework at scales from local to global. The product is unique because of the high temporal and spatial resolution, global coverage, and the number of species estimated. FINNv1 can be used for both hindcast and forecast or near-real time model applications and the results are being critically evaluated with models and observations whenever possible.

  13. High resolution of anthropogenic atmospheric emissions of 12 heavy metals in the three biggest metropolitan areas, China

    Science.gov (United States)

    Tian, H.; Zhu, C.

    2015-12-01

    Atmospheric emissions of typical toxic heavy metals from anthropogenic sources have received worldwide concerns due to their adverse effects on human health and the ecosystem. An integrated inventory of anthropogenic emissions of twelve HMs (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn) in the three biggest metropolitan areas, including Beijing-Tianjin-Hebei (BTH) region, Yangtze River Delta (YRD) region and Pearl River Delta (PRD) region, are developed for 1980-2012 by combining with detailed activity data and inter-annual dynamic emission factors which are determined by S-shaped curves on account of technology progress, economic development, and emission control. The results indicate total emissions of twelve HMs in the three metropolitan regions have increased from 5448.8 tons in 1980 to 19054.9 tons in 2012, with an annual average growth rate of about 4.0%. Due to significant difference in industrial structures and energy consumption compositions, remarkable distinctions can be observed with respect to source contributions of total HM emissions from above three metropolitan areas. Specifically, the ferrous metal smelting sector, coal combustion by industrial boilers and coal combustion by power plants are found to be the primary source of total HM emissions in the BTH region (about 34.2%), YRD region (about 28.2%) and PRD region (about 24.3%), respectively. Furthermore, we allocate the annual emissions of these heavy metals in 2012 at a high spatial resolution of 9 km × 9 km grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). The peak of HM emissions are mainly distributed over the grid cells of Beijing, Tianjin, Tangshan, Shijiazhuang, Handan and Baoding in the BTH region; Shanghai, Suzhou, Wuxi, Nanjing, Hangzhou, Ningbo in the YRD region; Guangzhou, Shenzhen, Dongguan, Foshan in the PYD region, respectively. Additionally, monthly emission profiles are established in order to further identify

  14. Quantification of uncertainty associated with United States high resolution fossil fuel CO2 emissions: updates, challenges and future plans

    Science.gov (United States)

    Gurney, K. R.; Chandrasekaran, V.; Mendoza, D. L.; Geethakumar, S.

    2010-12-01

    The Vulcan Project has estimated United States fossil fuel CO2 emissions at the hourly time scale and at spatial scales below the county level for the year 2002. Vulcan is built from a wide variety of observational data streams including regulated air pollutant emissions reporting, traffic monitoring, energy statistics, and US census data. In addition to these data sets, Vulcan relies on a series of modeling assumptions and constructs to interpolate in space, time and transform non-CO2 reporting into an estimate of CO2 combustion emissions. The recent version 2.0 of the Vulcan inventory has produced advances in a number of categories with particular emphasis on improved temporal structure. Onroad transportation emissions now avail of roughly 5000 automated traffic count monitors allowing for much improved diurnal and weekly time structure in our onroad transportation emissions. Though the inventory shows excellent agreement with independent national-level CO2 emissions estimates, uncertainty quantification has been a challenging task given the large number of data sources and numerous modeling assumptions. However, we have now accomplished a complete uncertainty estimate across all the Vulcan economic sectors and will present uncertainty estimates as a function of space, time, sector and fuel. We find that, like the underlying distribution of CO2 emissions themselves, the uncertainty is also strongly lognormal with high uncertainty associated with a relatively small number of locations. These locations typically are locations reliant upon coal combustion as the dominant CO2 source. We will also compare and contrast Vulcan fossil fuel CO2 emissions estimates against estimates built from DOE fuel-based surveys at the state level. We conclude that much of the difference between the Vulcan inventory and DOE statistics are not due to biased estimation but mechanistic differences in supply versus demand and combustion in space/time.

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

    International Nuclear Information System (INIS)

    Labas, R.

    2007-01-01

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

  16. Novel targets for positron emission tomography (PET) radiopharmaceutical tracers for visualization of neuroinflammation

    Science.gov (United States)

    Shchepetkin, I.; Shvedova, M.; Anfinogenova, Y.; Litvak, M.; Atochin, D.

    2017-08-01

    Non-invasive molecular imaging techniques can enhance diagnosis of neurological diseases to achieve their successful treatment. Positron emission tomography (PET) imaging can identify activated microglia and provide detailed functional information based on molecular biology. This imaging modality is based on detection of isotope labeled tracers, which emit positrons. The review summarizes the developments of various radiolabeled ligands for PET imaging of neuroinflammation.

  17. Effectiveness of lead aprons in positron emission tomography

    International Nuclear Information System (INIS)

    Bezerra Fonseca, R.; Amaral, A.

    2008-01-01

    Full text: In the last two decades, Positron Emission Tomography (PET) has emerged as clinical diagnostic technique, becoming one of the fastest growing imaging tools in modern nuclear medicine. Because 511 keV annihilation photon energy is much higher than the photon with mean energy of 140 keV emitted in Single Photon Computed Tomography (SPECT), medical staff working in PET studies receive a higher dose than those working only with SPECT tracers do. As a result, special attention must be paid to keep radiation exposure as low as reasonably achievable (ALARA principle). Lead equivalent apron is the principal personal protective equipment for technologists occupationally exposed to ionizing radiation in medical procedures and may be an important component in the ALARA program. However, in practices involving PET, 0.5 mm lead equivalent aprons have been used regardless of photon's energy. In this context, this work was designed for evaluating radioprotective effectiveness of such aprons in PET procedures. For this, the operational quantities personal dose equivalent H p (0.07) and H p (10) have been assessed by using MCNP4C code in a model of individual exposure to small source of 511 keV photons, representing the situation of injection of the radiopharmaceutical, in two situations: technologists wearing and not wearing 0.5 mm lead aprons. To represent the technologist a mathematical anthropomorphic phantom was employed, and the simulated source to subject distances varied between 40 to 100 cm, in steps of 10 cm. The results showed no significant differences between the values obtained for H p (10) in the two situations, pointing out that that there is no radioprotective influence of wearing such aprons on PET practices. Compared to simulations without such device, H p (0.07) increased up about 26% when technologist is wearing radioprotective aprons, depending on the source to subject distance. On the basis of this work, 0.5 mm lead equivalent aprons should not be

  18. Source data supported high resolution carbon emissions inventory for urban areas of the Beijing-Tianjin-Hebei region: Spatial patterns, decomposition and policy implications.

    Science.gov (United States)

    Cai, Bofeng; Li, Wanxin; Dhakal, Shobhakar; Wang, Jianghao

    2018-01-15

    This paper developed internationally compatible methods for delineating boundaries of urban areas in China. By integrating emission source data with existing official statistics as well as using rescaling methodology of data mapping for 1 km grid, the authors constructed high resolution emission gridded data in Beijing-Tianjin-Hebei (Jing-Jin-Ji) region in China for 2012. Comparisons between urban and non-urban areas of carbon emissions from industry, agriculture, household and transport exhibited regional disparities as well as sectoral differences. Except for the Hebei province, per capita total direct carbon emissions from urban extents in Beijing and Tianjin were both lower than provincial averages, indicating the climate benefit of urbanization, comparable to results from developed countries. Urban extents in the Hebei province were mainly industrial centers while those in Beijing and Tianjin were more service oriented. Further decomposition analysis revealed population to be a common major driver for increased carbon emissions but climate implications of urban design, economic productivity of land use, and carbon intensity of GDP were both cluster- and sector-specific. This study disapproves the one-size-fits-all solution for carbon mitigation but calls for down-scaled analysis of carbon emissions and formulation of localized carbon reduction strategies in the Jing-Jin-Ji as well as other regions in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. single photon emission tomography and positron emission tomography - Part 1 (October 2012), Part 2 (October 2010)

    International Nuclear Information System (INIS)

    Buvat, Irene

    2010-10-01

    The objective of this lecture is to present the single photon emission computed tomography (SPECT) and the positron emission tomography (PET) imaging techniques. Part 1 Content: 1 - Introduction: anatomic, functional and molecular imaging; 2 - Radiotracers: chemical and physical constraints, gamma photon emitters, positon emitters, radioisotopes production, emitters type and imaging techniques; 3 - Gamma cameras; 4 - Quantification in emission tomography: attenuation, scattering, un-stationary spatial resolution; 5 - Synthesis and conclusion. Part 2 content: 1 - Positon emitters; 2 - Positons detection: Coincidence detection (electronic collimation, PET detectors with gamma cameras, dedicated PET detectors, spectrometry); PET detectors type; time-of-flight PET; 2D PET; 3D PET; 3 - Quantification in emission tomography: detected events, attenuation, scattering, fortuitous coincidences, standardisation; 4 - Common SPECT and PET problems: partial volume effect, movement, tomographic reconstruction, calibration, dead time; 5 - Synthesis and conclusion

  20. Relevance of positron emission tomography (PET) in oncology

    International Nuclear Information System (INIS)

    Weber, W.A.; Avril, N.; Schwaiger, M.

    1999-01-01

    Background: The clinical use of positron emission tomography (PET) for detection and staging of malignant tumors is rapidly increasing. Furthermore, encouraging results for monitoring the effects of radio- and chemotherapy have been reported. Methods: This review describes the technical principles of PET and the biological characteristics of tracers used in oncological research and patient studies. The results of clinical studies published in peer reviewed journals during the last 5 years are summarized and clinical indications for PET scans in various tumor types are discussed. Results and Conclusions: Numerous studies have documented the high diagnostic accuracy of PET studies using the glucose analogue F-18-fluordeoxyglucose (FDG-PET) for detection and staging of malignant tumors. In this field, FDG-PET has been particularly successful in lung cancer, colorectal cancer, malignant lymphoma and melanoma. Furthermore, FDG-PET has often proven to be superior to morphological imaging techniques for differentation of tumor recurrence from scar tissue. Due to the high glucose utilization of normal gray matter radiolabeled amino-acids like C-11-methionine are superior to FDG for detection and delineation of brain tumors by PET. In the future, more specific markers of tumor cell proliferation and gene expression may allow the application of PET not only for dianostic imaging also but for non-invasive biological characterization of malignant tumors and early monitoring of therapeutic interventions. (orig.) [de

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

    International Nuclear Information System (INIS)

    Herscovitch, P.; Powers, W.J.

    1987-01-01

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

  2. European health telematics networks for positron emission tomography

    Science.gov (United States)

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

    2006-12-01

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

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

    CERN Document Server

    Powolny, François

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

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

    International Nuclear Information System (INIS)

    Kato, Takashi; Fukatsu, Hiroshi; Ito, Kengo; Tadokoro, Masanori; Ota, Toyohiro; Ikeda, Mitsuru; Isomura, Takayuki; Ito, Shigeki; Nishino, Masanari; Ishigaki, Takeo

    1995-01-01

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

  5. Positron emission tomography scans on kanji and kana

    International Nuclear Information System (INIS)

    Sakurai, Yasuhisa

    2002-01-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  7. Positron emission tomography/computed tomography imaging and rheumatoid arthritis.

    Science.gov (United States)

    Wang, Shi-Cun; Xie, Qiang; Lv, Wei-Fu

    2014-03-01

    Rheumatoid arthritis (RA) is a phenotypically heterogeneous, chronic, destructive inflammatory disease of the synovial joints. A number of imaging tools are currently available for evaluation of inflammatory conditions. By targeting the upgraded glucose uptake of infiltrating granulocytes and tissue macrophages, positron emission tomography/computed tomography with fluorine-18 fluorodeoxyglucose ((18) F-FDG PET/CT) is available to delineate inflammation with high sensitivity. Recently, several studies have indicated that FDG uptake in affected joints reflects the disease activity of RA. In addition, usage of FDG PET for the sensitive detection and monitoring of the response to treatment has been reported. Combined FDG PET/CT enables the detailed assessment of disease in large joints throughout the whole body. These unique capabilities of FDG PET/CT imaging are also able to detect RA-complicated diseases. Therefore, PET/CT has become an excellent ancillary tool to assess disease activity and prognosis in RA. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

  8. Quantifying the limitations of small animal positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Oxley, D.C. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom)], E-mail: dco@ns.ph.liv.ac.uk; Boston, A.J.; Boston, H.C.; Cooper, R.J.; Cresswell, J.R.; Grint, A.N.; Nolan, P.J.; Scraggs, D.P. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lazarus, I.H. [STFC Daresbury Laboratory, Warrington, WA4 4AD Cheshire (United Kingdom); Beveridge, T.E. [School of Materials and Engineering, Monash University, Melbourne (Australia)

    2009-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Karbe, H; Holthoff, V; Huber, M; Herholz, K; Wienhard, K; Wagner, R; Heiss, W D [Universitaetsklinik fuer Neurologie und Max-Planck-Institut fuer neurologische Forschung, Koeln (Germany)

    1992-01-01

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

  10. Positron Emission Tomography with Three-Dimensional Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Erlandsson, K.

    1996-10-01

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

  11. Positron Emission Tomography with Three-Dimensional Reconstruction

    International Nuclear Information System (INIS)

    Erlandsson, K.

    1996-10-01

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

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

    Science.gov (United States)

    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. Copyright © 2010. Published by Elsevier Inc.

  13. Imaging Cellular Proliferation in Prostate Cancer with Positron Emission Tomography

    Directory of Open Access Journals (Sweden)

    Hossein Jadvar

    2015-07-01

    Full Text Available Prostate cancer remains a major public health problem worldwide. Imaging plays an important role in the assessment of disease at all its clinical phases, including staging, restaging after definitive therapy, evaluation of therapy response, and prognostication. Positron emission tomography with a number of biologically targeted radiotracers has been demonstrated to have potential diagnostic and prognostic utility in the various clinical phases of this prevalent disease. Given the remarkable biological heterogeneity of prostate cancer, one major unmet clinical need that remains is the non-invasive imaging-based characterization of prostate tumors. Accurate tumor characterization allows for image-targeted biopsy and focal therapy as well as facilitates objective assessment of therapy effect. PET in conjunction with radiotracers that track the thymidine salvage pathway of DNA synthesis may be helpful to fulfill this necessity. We review briefly the preclinical and pilot clinical experience with the two major cellular proliferation radiotracers, [18F]-3’-deoxy-3’-fluorothymidine and [18F]-2’-fluoro-5-methyl-1-beta-D-arabinofuranosyluracil in prostate cancer.

  14. Carbon-11-methionine positron emission tomography imaging of chordoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hong [Department of Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan); Department of Medical Imaging, Research Center Hospital for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, 263-8555, Chiba (Japan); Yoshikawa, Kyosan; Tamura, Katsumi; Sagou, Kenji; Kandatsu, Susumu [Clinical Diagnosis Section, National Institute of Radiological Sciences, Chiba (Japan); Tian, Mei; Suhara, Tetsuya; Suzuki, Kazutoshi; Tanada, Shuji [Department of Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan); Tsujii, Hirohiko [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)

    2004-09-01

    Chordoma is a rare malignant bone tumor that arises from notochord remnants. This is the first trial to investigate the utility of {sup 11}C-methionine (MET) positron emission tomography (PET) in the imaging of chordoma before and after carbon-ion radiotherapy (CIRT). Fifteen patients with chordoma were investigated with MET-PET before and after CIRT and the findings analyzed visually and quantitatively. Tumor MET uptake was evaluated by tumor-to-nontumor ratio (T/N ratio). In 12 (80%) patients chordoma was clearly visible in the baseline MET-PET study with a mean T/N ratio of 3.3{+-}1.7. The MET uptake decreased significantly to 2.3{+-}1.4 after CIRT (P<0.05). A significant reduction in tumor MET uptake of 24% was observed after CIRT. Fourteen (93%) patients showed no local recurrence after CIRT with a median follow-up time of 20 months. This study has demonstrated that MET-PET is feasible for imaging of chordoma. MET-PET could provide important tumor metabolic information for the therapeutic monitoring of chordoma after CIRT. (orig.)

  15. Carbon-11-methionine positron emission tomography imaging of chordoma

    International Nuclear Information System (INIS)

    Zhang, Hong; Yoshikawa, Kyosan; Tamura, Katsumi; Sagou, Kenji; Kandatsu, Susumu; Tian, Mei; Suhara, Tetsuya; Suzuki, Kazutoshi; Tanada, Shuji; Tsujii, Hirohiko

    2004-01-01

    Chordoma is a rare malignant bone tumor that arises from notochord remnants. This is the first trial to investigate the utility of 11 C-methionine (MET) positron emission tomography (PET) in the imaging of chordoma before and after carbon-ion radiotherapy (CIRT). Fifteen patients with chordoma were investigated with MET-PET before and after CIRT and the findings analyzed visually and quantitatively. Tumor MET uptake was evaluated by tumor-to-nontumor ratio (T/N ratio). In 12 (80%) patients chordoma was clearly visible in the baseline MET-PET study with a mean T/N ratio of 3.3±1.7. The MET uptake decreased significantly to 2.3±1.4 after CIRT (P<0.05). A significant reduction in tumor MET uptake of 24% was observed after CIRT. Fourteen (93%) patients showed no local recurrence after CIRT with a median follow-up time of 20 months. This study has demonstrated that MET-PET is feasible for imaging of chordoma. MET-PET could provide important tumor metabolic information for the therapeutic monitoring of chordoma after CIRT. (orig.)

  16. Hepatic Pseudolymphoma with Fluorodeoxyglucose Uptake on Positron Emission Tomography

    Directory of Open Access Journals (Sweden)

    Kazuhiro Suzumura

    2017-12-01

    Full Text Available A 69-year-old woman with chronic hepatitis B was admitted to our hospital with a hepatic tumor. The levels of 2 tumor markers, carcinoembryonic antigen and carbohydrate antigen 19-9, were slightly elevated; however, the α-fetoprotein and protein levels induced by vitamin K antagonist II were within the normal limits. Abdominal ultrasonography showed a well-defined peripheral hypoechoic mass that was isoechoic and homogeneous on the inside. Computed tomography showed a poorly enhanced tumor of 13 mm in diameter in the 5th segment of the liver. Fluorodeoxyglucose positron emission tomography showed a slight uptake (maximum standard uptake value 3.4 by the hepatic tumor. These findings suggested cholangiocellular carcinoma, and we performed anterior segmentectomy of the liver. A histopathological examination showed a hepatic pseudolymphoma. The patient’s postoperative course was uneventful, and she remains alive without recurrence 5 months after undergoing surgery. In most cases, hepatic pseudolymphoma is preoperatively diagnosed as a malignant tumor and a definite diagnosis is made after resection. It is therefore necessary to consider hepatic pseudolymphoma as a differential diagnosis in patients with hepatic tumors.

  17. European health telematics networks for positron emission tomography

    International Nuclear Information System (INIS)

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

    2006-01-01

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

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

    International Nuclear Information System (INIS)

    Tang Ganghua; Wu Guangyuan

    2007-01-01

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

  19. European health telematics networks for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-20

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Shinji; Fujii, Kiyotaka; Matsushima, Toshio; Fukui, Masashi; Sadoshima, Shouzou; Kuwabara, Yasuo (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

    1992-03-01

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

  1. Quality assurance and radiation safety in positron emission tomography

    International Nuclear Information System (INIS)

    Kmetyuk, Ya.V.; Radosh, H.V.; Bezshyyko, O.A.; Golinka-Bezshyyko, L.O.; Kadenko, I.M.; Kazinova, O.A.; Nagai, A.O.

    2012-01-01

    Scientific studies, clinical experience and economic analysis have shown that the positron emission tomography (PET) is clinically and cost effective cancer diagnostics method. Combined PET and computed tomography (PET/CT) has proven clinical utility, particularly in the diagnosis, staging or restaging malignant disease and metastases, surgical planning, radiation therapy planning and evaluation of treatment response. The use of PET/CT has grown substantially in the past few years, with an increasing number of hospitals and installations of PET/CT imaging centers each year. In the same time combination of 2 procedures, each of which impart a radiation dose and, as a result, increases the deleterious influence for health, creates additional radiation safety issues. In these conditions the role of quality assurance (QA) and quality control (QC) programs is getting more and more important. We considered main QA and radiation safety requirements for whole PET technology chain from radio-pharmacy facilities to PET/CT scanning and patient release criteria. All these issues were considered and assessed having the example of PET facilities and technology chain of All-Ukrainian Center for Radiosurgery of the Clinical Hospital 'Feofania'

  2. Variation in positron emission tomography use after colon cancer resection.

    Science.gov (United States)

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

    2015-05-01

    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. 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. 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. 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. Copyright © 2015 by American Society of Clinical Oncology.

  3. Image-reconstruction algorithms for positron-emission tomography systems

    International Nuclear Information System (INIS)

    Cheng, S.N.C.

    1982-01-01

    The positional uncertainty in the time-of-flight measurement of a positron-emission tomography system is modelled as a Gaussian distributed random variable and the image is assumed to be piecewise constant on a rectilinear lattice. A reconstruction algorithm using maximum-likelihood estimation is derived for the situation in which time-of-flight data are sorted as the most-likely-position array. The algorithm is formulated as a linear system described by a nonseparable, block-banded, Toeplitz matrix, and a sine-transform technique is used to implement this algorithm efficiently. The reconstruction algorithms for both the most-likely-position array and the confidence-weighted array are described by similar equations, hence similar linear systems can be used to described the reconstruction algorithm for a discrete, confidence-weighted array, when the matrix and the entries in the data array are properly identified. It is found that the mean square-error depends on the ratio of the full width at half the maximum of time-of-flight measurement over the size of a pixel. When other parameters are fixed, the larger the pixel size, the smaller is the mean square-error. In the study of resolution, parameters that affect the impulse response of time-of-flight reconstruction algorithms are identified. It is found that the larger the pixel size, the larger is the standard deviation of the impulse response. This shows that small mean square-error and fine resolution are two contradictory requirements

  4. High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH, and Denitrification to C Mineralization.

    Directory of Open Access Journals (Sweden)

    Md Sainur Samad

    Full Text Available Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O and N2O/(N2O+N2 product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2 μmol N/h/vial were significantly associated with C mineralization (CO2 μmol/h/vial measured both under oxic (r2 = 0.62, p = 0.0015 and anoxic (r2 = 0.89, p<0.0001 conditions.

  5. Kalman-filtered compressive sensing for high resolution estimation of anthropogenic greenhouse gas emissions from sparse measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Jaideep; Lee, Jina; Lefantzi, Sophia; Yadav, Vineet; Michalak, Anna M.; van Bloemen Waanders, Bart Gustaaf; McKenna, Sean Andrew

    2013-09-01

    The estimation of fossil-fuel CO2 emissions (ffCO2) from limited ground-based and satellite measurements of CO2 concentrations will form a key component of the monitoring of treaties aimed at the abatement of greenhouse gas emissions. The limited nature of the measured data leads to a severely-underdetermined estimation problem. If the estimation is performed at fine spatial resolutions, it can also be computationally expensive. In order to enable such estimations, advances are needed in the spatial representation of ffCO2 emissions, scalable inversion algorithms and the identification of observables to measure. To that end, we investigate parsimonious spatial parameterizations of ffCO2 emissions which can be used in atmospheric inversions. We devise and test three random field models, based on wavelets, Gaussian kernels and covariance structures derived from easily-observed proxies of human activity. In doing so, we constructed a novel inversion algorithm, based on compressive sensing and sparse reconstruction, to perform the estimation. We also address scalable ensemble Kalman filters as an inversion mechanism and quantify the impact of Gaussian assumptions inherent in them. We find that the assumption does not impact the estimates of mean ffCO2 source strengths appreciably, but a comparison with Markov chain Monte Carlo estimates show significant differences in the variance of the source strengths. Finally, we study if the very different spatial natures of biogenic and ffCO2 emissions can be used to estimate them, in a disaggregated fashion, solely from CO2 concentration measurements, without extra information from products of incomplete combustion e.g., CO. We find that this is possible during the winter months, though the errors can be as large as 50%.

  6. Estimation of intersubject variability of cerebral blood flow measurements using MRI and positron emission tomography

    DEFF Research Database (Denmark)

    Henriksen, Otto Mølby; Larsson, Henrik B W; Hansen, Adam E

    2012-01-01

    PURPOSE: To investigate the within and between subject variability of quantitative cerebral blood flow (CBF) measurements in normal subjects using various MRI techniques and positron emission tomography (PET). MATERIALS AND METHODS: Repeated CBF measurements were performed in 17 healthy, young...

  7. Imaging prostate cancer: an update on positron emission tomography and magnetic resonance imaging

    DEFF Research Database (Denmark)

    Bouchelouche, Kirsten; Turkbey, Baris; Choyke, Peter

    2010-01-01

    , and molecular imaging information. Developments in imaging technologies, specifically magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT), have improved the detection rate of prostate cancer. MRI has improved lesion detection and local staging. Furthermore, MRI...

  8. Measurement of blood-brain barrier permeability with positron emission tomography in patients with multiple sclerosis

    International Nuclear Information System (INIS)

    Fieschi, C.; Pozzilli, C.; Bernardi, S.; Bozzao, L.; Lenzi, G.L.; Picozzi, P.; Iannotti, F.; Conforti, P.

    1988-01-01

    The purpose of the investigation was to elucidate the role of positron emission tomography using 68 Ga-EDTA in the study of blood-brain barrier abnormalities associated with multiple sclerosis. 14 refs.; 1 figure

  9. Readout of scintillator light with avalanche photodiodes for positron emission tomography

    International Nuclear Information System (INIS)

    Chen, Ruru; Fremout, A.; Tavernier, S.; Bruyndonckx, P.; Clement, D.; Loude, J.-F.; Morel, C.

    1999-01-01

    The noise properties and other relevant characteristics of avalanche photodiodes have been investigated with the perspective of replacing photomultiplier tubes in positron emission tomography. It is clearly demonstrated that they are a valid alternative to photomultiplier tubes in this application

  10. Imaging Atherosclerosis with Hybrid Positron Emission Tomography/Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Ripa, Rasmus Sejersten; Kjær, Andreas

    2015-01-01

    Noninvasive imaging of atherosclerosis could potentially move patient management towards individualized triage, treatment, and followup. The newly introduced combined positron emission tomography (PET) and magnetic resonance imaging (MRI) system could emerge as a key player in this context. Both...

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

    International Nuclear Information System (INIS)

    Baron, J.C.

    1986-05-01

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

  12. Software development for modeling positrons emission tomograph scanners

    International Nuclear Information System (INIS)

    Vieira, Igor Fagner

    2013-01-01

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

  13. Synthesis of the radiopharmaceuticals for positron emission tomography

    International Nuclear Information System (INIS)

    Biricova, V.; Kuruc, J.

    2007-01-01

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

  14. RELIABILITY OF POSITRON EMISSION TOMOGRAPHY-COMPUTED TOMOGRAPHY IN EVALUATION OF TESTICULAR CARCINOMA PATIENTS.

    Science.gov (United States)

    Nikoletić, Katarina; Mihailović, Jasna; Matovina, Emil; Žeravica, Radmila; Srbovan, Dolores

    2015-01-01

    The study was aimed at assessing the reliability of 18F-fluorodeoxyglucose positron emission tomography-computed tomography scan in evaluation of testicular carcinoma patients. The study sample consisted of 26 scans performed in 23 patients with testicular carcinoma. According to the pathohistological finding, 14 patients had seminomas, 7 had nonseminomas and 2 patients had a mixed histological type. In 17 patients, the initial treatment was orchiectomy+chemotherapy, 2 patients had orchiectomy+chemotherapy+retroperitoneal lymph node dissection, 3 patients had orchiectomy only and one patient was treated with chemotherapy only. Abnormal computed tomography was the main cause for the oncologist to refer the patient to positron emission tomography-computed tomography scan (in 19 scans), magnetic resonance imaging abnormalities in 1 scan, high level oftumor markers in 3 and 3 scans were perforned for follow-up. Positron emission tomography-computed tomography imaging results were compared with histological results, other imaging modalities or the clinical follow-up of the patients. Positron emission tomography-computed tomography scans were positive in 6 and negative in 20 patients. In two patients, positron emission tomography-computed tomography was false positive. There were 20 negative positron emission omography-computed tomography scans perforned in 18 patients, one patient was lost for data analysis. Clinically stable disease was confirmed in 18 follow-up scans performed in 16 patients. The values of sensitivty, specificity, accuracy, and positive- and negative predictive value were 60%, 95%, 75%, 88% and 90.5%, respectively. A hgh negative predictive value obtained in our study (90.5%) suggests that there is a small possibility for a patient to have future relapse after normal positron emission tomography-computed tomography study. However, since the sensitivity and positive predictive value of the study ire rather low, there are limitations of positive

  15. Confirmation of Elevated Methane Emissions in Utah's Uintah Basin With Ground-Based Observations and a High-Resolution Transport Model

    Science.gov (United States)

    Foster, C. S.; Crosman, E. T.; Holland, L.; Mallia, D. V.; Fasoli, B.; Bares, R.; Horel, J.; Lin, J. C.

    2017-12-01

    Large CH4 leak rates have been observed in the Uintah Basin of eastern Utah, an area with over 10,000 active and producing natural gas and oil wells. In this paper, we model CH4 concentrations at four sites in the Uintah Basin and compare the simulated results to in situ observations at these sites during two spring time periods in 2015 and 2016. These sites include a baseline location (Fruitland), two sites near oil wells (Roosevelt and Castlepeak), and a site near natural gas wells (Horsepool). To interpret these measurements and relate observed CH4 variations to emissions, we carried out atmospheric simulations using the Stochastic Time-Inverted Lagrangian Transport model driven by meteorological fields simulated by the Weather Research and Forecasting and High Resolution Rapid Refresh models. These simulations were combined with two different emission inventories: (1) aircraft-derived basin-wide emissions allocated spatially using oil and gas well locations, from the National Oceanic and Atmospheric Administration (NOAA), and (2) a bottom-up inventory for the entire U.S., from the Environmental Protection Agency (EPA). At both Horsepool and Castlepeak, the diurnal cycle of modeled CH4 concentrations was captured using NOAA emission estimates but was underestimated using the EPA inventory. These findings corroborate emission estimates from the NOAA inventory, based on daytime mass balance estimates, and provide additional support for a suggested leak rate from the Uintah Basin that is higher than most other regions with natural gas and oil development.

  16. Analysis of solute transport in plants using positron emission tomography

    International Nuclear Information System (INIS)

    Partelova, D.

    2016-01-01

    In the first part of the work, geometrically and radiochemically characterized standards (phantoms) imitating the plant tissues and allowing the exact quantification of visualised radioindicator in plant tissues were designed and prepared within the study of visual and analytical characteristics of used positron emission tomograph (microPET system) commercially developed for animal objects at visualization of thin objects. Individual experiments carried out by exposure of excised leaves of tobacco (Nicotiana tabacum L.) or radish (Raphanus sativus L.) in solutions of 2-deoxy-2-fluoro-D-glucose labelled with positron emitter 18 F (2-[ 18 F]FDG) containing 10-, 100-, or 1000-times higher concentrations of D-glucose (c glu ) in comparison with the original 2-[ 18 F]FDG solution showed that the significant changes in visualisation of 2-[ 18 F]FDG distribution as well as in chemical portion of 2-[ 18 F]FDG within the leaf blade were observed as result of increased c glu . In the experiments with the whole plants of tobacco or radish exposed in 2-[ 18 F]FDG solution through the root system, only minimal translocation of 18 F radioactivity into the above-ground parts of plants, also in the case of increased c glu , was observed, which suggest the role of root system as a selective barrier of 2-[ 18 F]FDG transport from roots to the above-ground parts. On the basis of mentioned knowledge and analytical approaches (application of prepared phantoms), the dynamic study of 2-[ 18 F]FDG uptake and transport within the excised leaf of tobacco or whole radish plant was carried out. The description of these processes was realized through the 3D PET images and through the quantification of 2-[ 18 F]FDG distribution within the chosen regions of interest from the point of view of accumulated 18 F radioactivity (in Bq) or amount of D-glucose (in μg) as well. Application of methods of multivariate analysis allows to found the similarities between studied objects mainly from the point

  17. [Human positron emission tomography with oral 11C-vinpocetine].

    Science.gov (United States)

    Vas, Adám; Christer, Halldin; Sóvágó, Judit; Johan, Sandell; Cselényi, Zsolt; Kiss, Béla; Kárpáti, Egon; Lars, Farde; Gulyás, Balázs

    2003-11-16

    Positron emission tomography (PET) is a useful tool for the investigation of certain physiological changes and for the evaluation of the distribution, and receptor binding of drugs labelled with positron emitting isotopes. Vinpocetine (ethyl-apovincaminate) is a neuroprotective drug widely used in the prevention and treatment of cerebrovascular diseases. In the clinical practice vinpocetine is usually administered to the patients in intravenous infusion followed by long-term oral treatment. Until presently human data describing vinpocetine's kinetics and brain distribution came from ex vivo (blood, plasma, liquor) and post mortem (brain autoradiography) measurements. The authors wished to investigate the kinetics and distribution of vinpocetine in the brain and body after oral administration with PET in order to prove, that PET is useful in the non-invasive in vivo determination of these parameters. Vinpocetine was labelled with carbon-11 and the radioactivity was measured by PET in the stomach, liver, brain, colon and kidneys in healthy male volunteers. The radioactivity in the blood and urine was also determined. After oral administration, [11C]vinpocetine appeared immediately in the stomach and within minutes in the liver and the blood. In the blood the level of radioactivity continuously increased until the end of the measurement period, whereas the fraction of the unchanged mother compound decreased. Radioactivity uptake and distribution in the brain were demonstrable from the tenth minute after the oral administration of the labelled drug (average maximum uptake: 0.7% of the administered total dose). Brain distribution was heterogeneous (with preferences in the thalamus, basal ganglia and occipital cortex), similar to the distribution previously reported by the authors after intravenous administration. Vinpocetine, administered orally to human volunteers, readily entered the bloodstream from the stomach and the gastrointestinal tract and thereafter passed the

  18. Development of a high-resolution emission inventory and its evaluation and application through air quality modeling for Jiangsu Province, China

    Science.gov (United States)

    Zhao, Yu; Zhou, Yaduan; Mao, Pan; Zhang, Jie

    2017-04-01

    Improved emission inventories combining detailed source information are crucial for better understanding the atmospheric chemistry and effectively making emission control policies using air quality simulation, particularly at regional or local scales. With the downscaled inventories directly applied, chemical transport model might not be able to reproduce the authentic evolution of atmospheric pollution processes at small spatial scales. Using the bottom-up approach, a high-resolution emission inventory was developed for Jiangsu China, including SO2, NOx, CO, NH3, volatile organic compounds (VOCs), total suspended particulates (TSP), PM10, PM2.5, black carbon (BC), organic carbon (OC), and CO2. The key parameters relevant to emission estimation for over 6000 industrial sources were investigated, compiled and revised at plant level based on various data sources and on-site survey. As a result, the emission fractions of point sources were significantly elevated for most species. The improvement of this provincial inventory was evaluated through comparisons with other inventories at larger spatial scales, using satellite observation and air quality modeling. Compared to the downscaled Multi-resolution Emission Inventory for China (MEIC), the spatial distribution of NOX emissions in our provincial inventory was more consistent with summer tropospheric NO2 VCDs observed from OMI, particularly for the grids with moderate emission levels, implying the improved emission estimation for small and medium industrial plants by this work. Three inventories (national, regional, and provincial by this work) were applied in the Models-3/Community Multi-scale Air Quality (CMAQ) system for southern Jiangsu October 2012, to evaluate the model performances with different emission inputs. The best agreement between available ground observation and simulation was found when the provincial inventory was applied, indicated by the smallest normalized mean bias (NMB) and normalized mean

  19. Satellite constraint for emissions of nitrogen oxides from anthropogenic, lightning and soil sources over East China on a high-resolution grid

    Directory of Open Access Journals (Sweden)

    J.-T. Lin

    2012-03-01

    Full Text Available Vertical column densities (VCDs of tropospheric nitrogen dioxide (NO2 retrieved from space provide valuable information to estimate emissions of nitrogen oxides (NOx inversely. Accurate emission attribution to individual sources, important both for understanding the global biogeochemical cycling of nitrogen and for emission control, remains difficult. This study presents a regression-based multi-step inversion approach to estimate emissions of NOx from anthropogenic, lightning and soil sources individually for 2006 over East China on a 0.25° long × 0.25° lat grid, employing the DOMINO product version 2 retrieved from the Ozone Monitoring Instrument. The inversion is done gridbox by gridbox to derive the respective emissions, taking advantage of differences in seasonality between anthropogenic and natural sources. Lightning and soil emissions are combined together for any given gridbox due to their similar seasonality; and their different spatial distributions are used implicitly for source separation to some extent. The nested GEOS-Chem model for East Asia is used to simulate the seasonal variations of different emission sources and impacts on VCDs of NO2 for the inversion purpose. Sensitivity tests are conducted to evaluate key assumptions embedded in the inversion process. The inverse estimate suggests annual budgets of about 7.1 TgN (±39%, 0.21 TgN (±61%, and 0.38 TgN (±65% for the a posteriori anthropogenic, lightning and soil emissions, respectively, about 18–23% higher than the respective a priori values. The enhancements in anthropogenic emissions are largest in cities and areas with extensive use of coal, particularly in the north in winter, as evident on the high-resolution grid. Derived soil emissions are consistent with recent bottom-up estimates. They are less than 6% of anthropogenic emissions annually, increasing to about 13% for July. Derived lightning emissions are about 3% of

  20. Positron emission computerized tomography: a potential tool for in vivo quantitation of the distribution of radiopharmaceuticals

    International Nuclear Information System (INIS)

    Huebner, K.F.; King, P.; Gibbs, W.D.; Washburn, L.C.; Hayes, R.L.

    1981-01-01

    The principles and some of the difficulties in quantitative positron emission computerized tomography have been discussed. We have shown that randoms and scattered events are a major cause of noise and counting errors in positron emission computerized tomography. The noise has been identified as a convoluting process and a mathematical solution has been presented. Examples of phantom studies and in vivo measurements have demonstrated that the distribution of positron emitting radiopharmaceuticals can be quantitated with much improved accuracy using the deconvolution equation to remove undesired noise

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

    International Nuclear Information System (INIS)

    Guermazi, Fadhel; Hamza, F; Amouri, W.; Charfeddine, S.; Kallel, S.; Jardak, I.

    2013-01-01

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

  2. Visualisation and Quantification of Transport in Barrier Rocks with Positron Emission Tomography

    Science.gov (United States)

    Kulenkampff, J.; Gajewski, C.; Gründig, M.; Lippmann-Pipke, J.; Mittmann, H.; Richter, M.; Wolf, M.

    2009-04-01

    In tight barrier rocks laboratory observation of radionuclide transport and determination of transport parameters is a demanding and interminable task, because of slow rates, small concentrations, and intricate chemical interactions. The validity of results from common laboratory methods, like flow- and diffusion experiments on small samples, is limited by the heterogeneity of the pathways and adherent upscaling issues, because homogeneous conditions have to be presumed for these input-output investigations. But nano-pores or micro-fractures could be present, which would provide pathways for heterogeneous transport processes. Transport properties of these pathways are most influential boundary conditions for reactions between fluid components and crystal surfaces. We propose Positron Emission Tomography (GEO-PET) as an appropriate method for direct observation of heterogeneous transport of radiotracers in tight material on the laboratory scale. With high-resolution PET scanners, which are common instruments of biomedical research ("small animal PET"), it is possible to determine the spatio-temporal distribution of the tracer activity with a resolution of almost 1 mm during about three periods of the tracer half-life (half-lives of some applicable PET tracers: 18F: 1.8 h, 124I: 4.2 days, 58Co: 70.8 days). The PET tracer is applied as ion in solution or as marker for compounds, like colloids. The most considerable difference between PET applications on geomaterial compared to biological tissue is the stronger attenuation and scattering of radiation because of the higher density of rock material. After travelling the positron attenuation length in dense material (about 1 mm), the positron annihilates in contact with an electron, transmitting two photons with 511 keV, propagating in antiparallel direction. The sample size of geomaterial is limited by the attenuation length of these photons. By applying an appropriate attenuation correction it is possible to investigate

  3. WE-H-207A-01: Computational Evaluation of High-Resolution 18F Positron Imaging Using Radioluminescence Microscopy with Lu2O3: Eu Thin-Film Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q; Sengupta, D; Pratx, G [Stanford University, Palo Alto, CA (United States)

    2016-06-15

    Purpose: Radioluminescence microscopy, an emerging and powerful tool for high resolution beta imaging, has been applied to molecular imaging of cellular metabolism to understand tumor biology. A novel thin-film (10 µm thickness) scintillator made of Lu{sub 2}O{sub 3}: Eu has been developed to enhance the system performance. However the advances of radioluminescence imaging with Lu{sub 2}O{sub 3}scintillator compared with that using conventional scintillator have not been explored theoretically to date. To validate the advantages of the thin-film scintillator, this study uses a novel computational simulation framework to evaluate the performance of radioluminescence microscopy using both conventional and thin-film scintillators. Methods: Numerical models for different stages of positron imaging are established. Positron from {sup 18}F passing through the scintillator and its neighbor structures are modeled by Monte-Carlo simulation using Geant4. The propagation and focus of photons by the microscope are modeled by convolution with a depth-varying point spread function generated by the Gibson-Lanni model. Photons focused on the detector plane are then captured and converted into electronic signals by an electron multiplication (EM) CCD camera, which is described by a photosensor model considering various noises and charge amplification. Results: The performance metrics of radioluminescence imaging with a thin-film Lu{sub 2}O{sub 3} and conventional CdWO{sub 4} scintillator are compared, including spatial resolution, sensitivity, positron track area and intensity. The spatial resolution of Lu{sub 2}O{sub 3} system can achieve 10 µm maximally, a 12 µm enhancement from that obtained from CdWO{sub 4} system. Meanwhile, the system with Lu{sub 2}O{sub 3} scintillator can provide a higher mean sensitivity: 40% compared with that (21.5%) obtained from CdWO{sub 4} system. Moreover, the simulation results are in good agreement with previous experimental measurements

  4. Influence of Respiratory Gating, Image Filtering, and Animal Positioning on High-Resolution Electrocardiography-Gated Murine Cardiac Single-Photon Emission Computed Tomography

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2015-01-01

    Full Text Available Cardiac parameters obtained from single-photon emission computed tomographic (SPECT images can be affected by respiratory motion, image filtering, and animal positioning. We investigated the influence of these factors on ultra-high-resolution murine myocardial perfusion SPECT. Five mice were injected with 99m technetium (99mTc-tetrofosmin, and each was scanned in supine and prone positions in a U-SPECT-II scanner with respiratory and electrocardiographic (ECG gating. ECG-gated SPECT images were created without applying respiratory motion correction or with two different respiratory motion correction strategies. The images were filtered with a range of three-dimensional gaussian kernels, after which end-diastolic volumes (EDVs, end-systolic volumes (ESVs, and left ventricular ejection fractions were calculated. No significant differences in the measured cardiac parameters were detected when any strategy to reduce or correct for respiratory motion was applied, whereas big differences (> 5% in EDV and ESV were found with regard to different positioning of animals. A linear relationship (p < .001 was found between the EDV or ESV and the kernel size of the gaussian filter. In short, respiratory gating did not significantly affect the cardiac parameters of mice obtained with ultra-high-resolution SPECT, whereas the position of the animals and the image filters should be the same in a comparative study with multiple scans to avoid systematic differences in measured cardiac parameters.

  5. High-resolution emission tomography of small laboratory animals: physics and gamma-astronomy meet molecular biology

    International Nuclear Information System (INIS)

    Beekman, F.J.; Colijn, A.P.; Vastenhouw, B.; Wiegant, V.M.; Gerrits, M.A.F.M.

    2003-01-01

    Molecular imaging can be defined as the characterization and measurement of biological processes in living animals, model systems and humans at the cellular and molecular level using remote imaging detectors. An example concerns the mapping of the distributions of radioactively labeled molecules in laboratory animals which is of crucial importance for life sciences. Tomographic methods like Single Photon Emission Computed Tomography (SPECT) offer a possibility to visualize distributions of radioactively labeled molecules in living animals. Miniature tomography systems, derived from their clinical counterparts, but with a much higher image resolution are under development in several institutes. An example is U-SPECT that will be discussed in the present paper. Such systems are expected to accelerate several biomedical research procedures, the understanding of gene and protein function, as well as pharmaceutical development

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

    International Nuclear Information System (INIS)

    Blomqvist, G.; Lammertsma, A.A.; Mazoyer, B.; Wienhard, K.

    1995-01-01

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

  7. 18F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

    International Nuclear Information System (INIS)

    Ho, Kung-Chu; Yen, Tzu-Chen; Lai, Chyong-Huey; Wu, Tzu-I; Chang, Ting-Chang; Huang, Huei-Jean; Ng, Koon-Kwan; Lin, Gigin; Wang, Chun-Chieh; Hsueh, Swei

    2008-01-01

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

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

    Science.gov (United States)

    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.

  9. Oxygen-15 labelled water production for positron emission tomography

    International Nuclear Information System (INIS)

    Janus, A.; Sachinidis, J.I.; Chan, J.G.; Tochon-Danguy, H.J.

    1998-01-01

    Full text: Functional imaging using positron emission tomography (PET) and 15 O-labelled compounds is both scientifically and clinically challenging. The short half-life of oxygen-15 (t 1/2 = 2 min) allows for multiple administration to a patient without exceeding acceptable levels of absorbed radiation dose and without excessive delay between administrations. The clinical usefulness of [ 15 O]-labelled water for cerebral blood flow measurements has been well established. Here we report the development and construction of a [ 15 O]water generator based on an earlier design from Hammersmith Hospital, London. The cyclotron produces a continuous flow of [ 15 O]O 2 gas by the irradiation of a natural nitrogen target (1% O 2 in N 2 ) with a 5 MeV deuteron beam, via the nuclear reaction ( 14 N(d,n) 15 O). The radioactive gas is then mixed with 5% hydrogen in nitrogen and piped to the water generator located in the scanner room. The O 2 /N 2 gas mixture is reacted over a palladium catalyst at 1500 deg C to produce [ 15 O]H 2 O vapour. The vapour passes through an exchanger where it diffuses across a semi-permeable membrane (cellulose acetate) into saline solution. At the optimum gas flow- rate of 500 mL/min, more than 95% of the radioactive oxygen is converted to radioactive water. Waste radioactive gas is piped back to the cyclotron vault to decay before release into the atmosphere. The saline solution (0.9% NaCl) is pumped continuously through the system at 6 mL/min with an infusion pump (3M AVI470). The present system has been in operation for more than a year and has been used for clinical evaluation of stroke patients and for brain activation research studies

  10. Study of brain metabolism using positron emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Heiss, W D

    1983-03-21

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

  11. Diagnosis of temporal lobe epilepsy by positron emission tomography

    International Nuclear Information System (INIS)

    Shimizu, Hiroyuki; Ishijima, Buichi; Iio, Masaaki.

    1985-01-01

    Positron emission tomography(PET) was performed in 18 temporal lobe epileptics. About 20 mCi of 11 C-glucose was perorally administered to the patients and 30 minutes later scanning was started when the transport of 11 C-glucose from blood to the brain tissue reached equilibrium. At the level of 25mm above orbitomeatal line, the slice image of the temporal lobe shows a relatively high metabolic oval ring involving the amygdala, hippocapal formation and the hippocampal gyrus medially and the T 1 , T 2 and T 3 neocortices laterally in normal subjects. The epileptic focus, when detected on PET images, was observed as a defect in this oval ring. In 15(83.3%) out of 18 cases, the location of epileptic focus was confirmed as a low metabolic defect. This diagnosis rate was higher than that of other focal epilepsy by PET study. The locations of foci were devided into three types: mesial (5 cases), lateral (4 cases) and combined (6 cases). The seizure symptoms of the patients were analyzed in terms of the correspondence to the focus types. The results showed that automatism and pseudoabsence had a close relation to the mesial and combined types and psychical, vertiginous or visual seizures correlated to the combined and lateral types. Visceral or motor seizures were induced equally by any focus types. These facts suggested that automatism and pseudoabsence were correlated with the mesial organs such as the amygdala and hippocampus and psychical, vertiginous or visual seizures had origin in lateral neocortices. Visceral or motor seizures were supposed to be the results of the spread from the temporal focus to the adjacent structures. It was concluded that PET was very useful in localization diagnosis of temporal lobe epilepsy. In surgical treatment of epilepsy, in which the knowledge of the exact extent of epileptic foci is strongly demanded, PET study will offer invaluable data to the strategy of operation and foreseeing its prognosis. (author)

  12. Fluorodeoxyglucose positron emission tomography in pulmonary carcinoid tumors

    International Nuclear Information System (INIS)

    Gasparri, R.; Rezende, G. C.; Brambilla, D.; Petrella, F.; Galetta, D.; Spaggiari, L.; Fazio, N.; Maisonneuve, P.; Travaini, L. L.; Paganelli, G.

    2015-01-01

    The role of fluorodeoxyglucose positron emission tomography (FDG-PET) as an additional investigation to computer tomography for pulmonary carcinoid tumors remains controversial. The aim of this study was to assess the role of FDG-PET for the diagnosis and staging of pulmonary carcinoid tumors. It has been performed a retrospective mono-institutional analysis of data from 97 patients with pathologically confirmed pulmonary carcinoid tumor who had been operated on between July 1998 and April 2009 and had had a preoperative FDG-PET scan performed. Sixty-five (67%) of the 97 tumors were typical (TC) and 32 (33%) atypical (AC) carcinoid tumors. Overall FDG-PET sensitivity was 67% being lower for TC (60%) than for AC (81%) (P=0.04). FDG-PET negative tumors were smaller than FDG-PET positive tumors, with a respective median size of 15 and 17 mm (P=0.02). Median SUVmax for FDG-PET-positive tumors was 4.0 (2.8-5.1) with no difference between TC and AC tumors. Median Ki-67 expression was respectively 4.7% and 3.1% for FDG-PET positive and FDG-PET negative tumors (P=0.05). During a median follow-up of 49 months (interquartile range 30-63 months), 9 patients (4TC, 5AC) developed recurrent disease. Neither SUVmax nor Ki-67 expression resulted associated with disease-free survival. With an overall sensitivity of 67%, FDG-PET has shown to be useful in the preoperative work-up of patients with suspect lung carcinoid tumors. In particular it could have a role in larger tumors. These results warrant a prospective evaluation of FDG-PET in the staging of lung carcinoid tumor.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-09-01

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

  15. Alcohol ADME in primates studied with positron emission tomography.

    Directory of Open Access Journals (Sweden)

    Zizhong Li

    Full Text Available 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.The ADME of C-11 labeled alcohol, CH(3 (11CH(2OH, 1 and C-11 and deuterium dual labeled alcohol, CH(3 (11CD(2OH, 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 (C(max; peak uptake time (T(max, half-life of peak uptake (T(1/2, the area under the curve (AUC(60 min, and the residue uptake (C(60 min.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.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.

  16. Anomalous positron emission in heavy ion-collisions

    International Nuclear Information System (INIS)

    Kienle, P.

    1986-09-01

    In section two we shortly present the experimental methods and first results on positron lines. Section three deals with the dependence of the positron line production on the charge of the collision system, bombarding energy and scattering angle. The results of the first e + -e - -coincidence studies are reviewed in section 4. In the last paragraph we make some remarks on future developments of the experimental methods. (orig./HSI)

  17. High resolution tomographic instrument development

    International Nuclear Information System (INIS)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational

  18. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  19. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  20. Development of a multiplexed readout with high position resolution for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sangwon; Choi, Yong [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul 04107 (Korea, Republic of); Kang, Jihoon [Department of Biomedical Engineering, Chonnam National University, Yeosu 550-749 (Korea, Republic of); Jung, Jin Ho [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul 04107 (Korea, Republic of)

    2017-04-01

    Detector signals for positron emission tomography (PET) are commonly multiplexed to reduce the number of digital processing channels so that the system can remain cost effective while also maintaining imaging performance. In this work, a multiplexed readout combining Anger position estimation algorithm and position decoder circuit (PDC) was developed to reduce the number of readout channels by a factor of 24, 96-to-4. The data acquisition module consisted of a TDC (50 ps resolution), 4-channel ADCs (12 bit, 105 MHz sampling rate), 2 GB SDRAM and USB3.0. The performance of the multiplexed readout was assessed with a high-resolution PET detector block composed of 2×3 detector modules, each consisting of an 8×8 array of 1.52×1.52×6 mm{sup 3} LYSO, a 4×4 array of 3×3 mm{sup 2} silicon photomultiplier (SiPM) and 13.4×13.4 mm{sup 2} light guide with 0.7 mm thickness. The acquired flood histogram showed that all 384 crystals could be resolved. The average energy resolution at 511 keV was 13.7±1.6% full-width-at-half-maximum (FWHM) and the peak-to-valley ratios of the flood histogram on the horizontal and vertical lines were 18.8±0.8 and 22.8±1.3, respectively. The coincidence resolving time of a pair of detector blocks was 6.2 ns FWHM. The reconstructed phantom image showed that rods down to a diameter of 1.6 mm could be resolved. The results of this study indicate that the multiplexed readout would be useful in developing a PET with a spatial resolution less than the pixel size of the photosensor, such as a SiPM array.

  1. Development of an angled Si-PM-based detector unit for positron emission mammography (PEM) system

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Kouhei, E-mail: nakanishi.kouhei@c.mbox.nagoya-u.ac.jp; Yamamoto, Seiichi

    2016-11-21

    Positron emission mammography (PEM) systems have higher sensitivity than clinical whole body PET systems because they have a smaller ring diameter. However, the spatial resolution of PEM systems is not high enough to detect early stage breast cancer. To solve this problem, we developed a silicon photomultiplier (Si-PM) based detector unit for the development of a PEM system. Since a Si-PM's channel is small, Si-PM can resolve small scintillator pixels to improve the spatial resolution. Also Si-PM based detectors have inherently high timing resolution and are able to reduce the random coincidence events by reducing the time window. We used 1.5×1.9×15 mm LGSO scintillation pixels and arranged them in an 8×24 matrix to form scintillator blocks. Four scintillator blocks were optically coupled to Si-PM arrays with an angled light guide to form a detector unit. Since the light guide has angles of 5.625°, we can arrange 64 scintillator blocks in a nearly circular shape (a regular 64-sided polygon) using 16 detector units. We clearly resolved the pixels of the scintillator blocks in a 2-dimensional position histogram where the averages of the peak-to-valley ratios (P/Vs) were 3.7±0.3 and 5.7±0.8 in the transverse and axial directions, respectively. The average energy resolution was 14.2±2.1% full-width at half-maximum (FWHM). By including the temperature dependent gain control electronics, the photo-peak channel shifts were controlled within ±1.5% with the temperature from 23 °C to 28 °C. With these results, in addition to the potential high timing performance of Si-PM based detectors, our developed detector unit is promising for the development of a high-resolution PEM system.

  2. Advanced modeling in positron emission tomography using Monte Carlo simulations for improving reconstruction and quantification

    International Nuclear Information System (INIS)

    Stute, Simon

    2010-01-01

    Positron Emission Tomography (PET) is a medical imaging technique that plays a major role in oncology, especially using "1"8F-Fluoro-Deoxyglucose. However, PET images suffer from a modest spatial resolution and from high noise. As a result, there is still no consensus on how tumor metabolically active volume and tumor uptake should be characterized. In the meantime, research groups keep producing new methods for such characterizations that need to be assessed. A Monte Carlo simulation based method has been developed to produce simulated PET images of patients suffering from cancer, indistinguishable from clinical images, and for which all parameters are known. The method uses high resolution PET images from patient acquisitions, from which the physiological heterogeneous activity distribution can be modeled. It was shown that the performance of quantification methods on such highly realistic simulated images are significantly lower and more variable than using simple phantom studies. Fourteen different quantification methods were also compared in realistic conditions using a group of such simulated patients. In addition, the proposed method was extended to simulate serial PET scans in the context of patient monitoring, including a modeling of the tumor changes, as well as the variability over time of non-tumoral physiological activity distribution. Monte Carlo simulations were also used to study the detection probability inside the crystals of the tomograph. A model of the crystal response was derived and included in the system matrix involved in tomographic reconstruction. The resulting reconstruction method was compared with other sophisticated methods for modeling the detector response in the image space, proposed in the literature. We demonstrated the superiority of the proposed method over equivalent approaches on simulated data, and illustrated its robustness on clinical data. For a same noise level, it is possible to reconstruct PET images offering a

  3. Combining high-resolution gross domestic product data with home and personal care product market research data to generate a subnational emission inventory for Asia.

    Science.gov (United States)

    Hodges, Juliet Elizabeth Natasha; Vamshi, Raghu; Holmes, Christopher; Rowson, Matthew; Miah, Taqmina; Price, Oliver Richard

    2014-04-01

    Environmental risk assessment of chemicals is reliant on good estimates of product usage information and robust exposure models. Over the past 20 to 30 years, much progress has been made with the development of exposure models that simulate the transport and distribution of chemicals in the environment. However, little progress has been made in our ability to estimate chemical emissions of home and personal care (HPC) products. In this project, we have developed an approach to estimate subnational emission inventory of chemical ingredients used in HPC products for 12 Asian countries including Bangladesh, Cambodia, China, India, Indonesia, Laos, Malaysia, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam (Asia-12). To develop this inventory, we have coupled a 1 km grid of per capita gross domestic product (GDP) estimates with market research data of HPC product sales. We explore the necessity of accounting for a population's ability to purchase HPC products in determining their subnational distribution in regions where wealth is not uniform. The implications of using high resolution data on inter- and intracountry subnational emission estimates for a range of hypothetical and actual HPC product types were explored. It was demonstrated that for low value products (500 US$ per capita/annum required to purchase product) the implications on emissions being assigned to subnational regions can vary by several orders of magnitude. The implications of this on conducting national or regional level risk assessments may be significant. Further work is needed to explore the implications of this variability in HPC emissions to enable the HPC industry and/or governments to advance risk-based chemical management policies in emerging markets. © 2013 SETAC.

  4. High-resolution inversion of OMI formaldehyde columns to quantify isoprene emission on ecosystem-relevant scales: application to the southeast US

    Science.gov (United States)

    Kaiser, Jennifer; Jacob, Daniel J.; Zhu, Lei; Travis, Katherine R.; Fisher, Jenny A.; González Abad, Gonzalo; Zhang, Lin; Zhang, Xuesong; Fried, Alan; Crounse, John D.; St. Clair, Jason M.; Wisthaler, Armin

    2018-04-01

    Isoprene emissions from vegetation have a large effect on atmospheric chemistry and air quality. Bottom-up isoprene emission inventories used in atmospheric models are based on limited vegetation information and uncertain land cover data, leading to potentially large errors. Satellite observations of atmospheric formaldehyde (HCHO), a high-yield isoprene oxidation product, provide top-down information to evaluate isoprene emission inventories through inverse analyses. Past inverse analyses have however been hampered by uncertainty in the HCHO satellite data, uncertainty in the time- and NOx-dependent yield of HCHO from isoprene oxidation, and coarse resolution of the atmospheric models used for the inversion. Here we demonstrate the ability to use HCHO satellite data from OMI in a high-resolution inversion to constrain isoprene emissions on ecosystem-relevant scales. The inversion uses the adjoint of the GEOS-Chem chemical transport model at 0.25° × 0.3125° horizontal resolution to interpret observations over the southeast US in August-September 2013. It takes advantage of concurrent NASA SEAC4RS aircraft observations of isoprene and its oxidation products including HCHO to validate the OMI HCHO data over the region, test the GEOS-Chem isoprene oxidation mechanism and NOx environment, and independently evaluate the inversion. This evaluation shows in particular that local model errors in NOx concentrations propagate to biases in inferring isoprene emissions from HCHO data. It is thus essential to correct model NOx biases, which was done here using SEAC4RS observations but can be done more generally using satellite NO2 data concurrently with HCHO. We find in our inversion that isoprene emissions from the widely used MEGAN v2.1 inventory are biased high over the southeast US by 40 % on average, although the broad-scale distributions are correct including maximum emissions in Arkansas/Louisiana and high base emission factors in the oak-covered Ozarks of southeast

  5. Low-energy positron and electron diffraction and positron-stimulated secondary electron emission from Cu(100)

    International Nuclear Information System (INIS)

    Weiss, A.H.

    1983-01-01

    The results of two series of experiments are reported. In the first, an electrostatically guided beam of low-energy (40-400 eV) positrons, delta/sub p/ was used to study low-energy positron diffraction (LEPD) from a Cu(100) surface under ultrahigh-vacuum conditions. Low-energy electron diffraction (LEED) data were obtained from the same sample in the same apparatus. Comparison of LEPD and LEED intensity versus energy data with model calculations made using computer programs developed by C.B. Duke and collaborators indicated that: LEPD data is adequately modeled using potentials with no exchange-correlation term. The inelastic mean free path, lambda/sub ee/, is shorter for positrons than for electrons at low (< approx.80 eV). LEED is better than LEPD at making a determination of the first-layer spacing of Cu(100) for the particular data set reported. In the second set of experiments, the same apparatus and sample were used to compare positron- and electron-stimulated secondary-electron emission (PSSEE and ESSEE). The results were found to be consistent with existing models of secondary-electron production for metals. The energy distributions of secondary-electrons had broad low-energy (<10 eV) peaks for both positron and electron stimulation. But the PSEE distribution showed no elastic peak. Measurements of secondary-electron angular distributions, found to be cosine-like in both the PSSEE and ESSEE case, were used to obtain total secondary yield ratios, delta, at four beam energies ranging from 40-400 eV. The secondary yield ratio for primary positrons and the yield for primary electrons, delta/sub e/, were similar at these energies. For 400-eV primary particles the secondary yields were found to be delta/sub p/ = 0.94 +/- 0.12 and delta/sub e/ = 0.94 +/- 0./12, giving a ratio of unity for positron-stimulated secondary yield to electron-stimulated secondary yield

  6. Evaluation of esophageal cancer by positron emission tomography

    International Nuclear Information System (INIS)

    Himeno, Shinji; Yasuda, Seiei; Shimada, Hideo; Tajima, Tomoo; Makuuchi, Hiroyasu

    2002-01-01

    A retrospective study was performed to determine the indications for positron emission tomography (PET) using [ 18 F]fluorodeoxyglucose (FDG) in patients with esophageal cancer, including those with early cancer, and to investigate whether the tumor-to-normal ratio (T/N ratio) could be used as a substitute for the standardized uptake value (SUV). Thirty-six patients were included in the study. Thirty-one patients who had 36 biopsy-proven lesions (35 squamous cell carcinomas and one small cell carcinoma) underwent PET study prior to treatment. PET images were evaluated visually and the relationship between the depth of invasion and the PET findings were examined in 22 lesions of 19 patients from whom specimens were obtained from the primary tumor by surgery or endoscopic mucosal resection. PET results were also compared with computed tomography (CT) and endoscopic ultrasonography (EUS) for detection of regional lymph node metastases in 18 patients who underwent extended lymph node dissection. Five patients underwent PET studies for the detection of recurrence and the PET findings were compared with their CT findings. The T/N ratio and the SUV were calculated for 20 primary tumors. Among the 15 tumors that were pT1b or greater, all 15 were positive on PET and all seven of the lesions confined to the mucosa (Tis or T1a) were negative. The sensitivity, specificity and accuracy of detecting nodal involvement were, respectively, 37.5, 96.1 and 88.3% by CT, 30.8, 88.5 and 81.0% by EUS and 41.7, 100 and 92.2% by PET. More sites of recurrence were detected by PET than by CT. There was no statistically significant correlation between the SUV and the T/N ratio. PET imaging can detect primary esophageal cancer with a depth of invasion of T1b or greater, but Tis and T1a tumors are undetectable. PET seems to be more accurate than CT or EUS for diagnosing lymph node metastasis. The T/N ratio cannot be used as a substitute for the SUV. (author)

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

    International Nuclear Information System (INIS)

    Karim, Kamran Said

    2010-01-01

    Transparent ceramics are becoming more and more important for two new types of applications. On the one hand in cases where high mechanical and thermal demands in combination with optical properties are required, on the other hand where the optical properties of transparent materials like glass are not sufficient e.g. in positron-emission-tomography (PET) diagnostics. Most state of the art PET-scanners are using high-priced single crystals as scintillator material. The technological challenge is to replace single crystal by cost-efficient transparent ceramics. Producing transparent ceramics is ordered in synthesis of the powders and in manufacturing of these into transparent ceramics. The aim of this work was to synthesize single phase yttrium-alumina-and Luthetiumalumina-garnet (YAG, LuAG) powders partially doped with neodymium or praseodymium by four different synthesis routes (Pechini-synthesis, sol-gel-route, coprecipitation and solid state reactions). Additionally industrial LuAG and LuPO 4 powders were characterized and manufactured. The powders were processed as submicron- and nanopowders. The compaction of nanopowder greenbodies sintered at high temperatures leads to a ''cross-over'' between both manufacturing route. Newly produced single-phase powders were homogenized with additions of sintering additives like tetraethyl orthosilicate (TEOS) and binders like polyvinyl alcohol (PVA). Moulding the powders were carried out by uniaxial pressing, cold isostatic pressing and in individual cases also by slip casting. The achieved green densities were in a range of 25-42 %. Examination of calcination behaviour leads to a calcination temperature of 1000 C with 2 hours dwell time in air atmosphere. Only solid state reactions resulted into transparent YAG, YAG:Pr, LuAG, LuAG:Pr ceramics. Solid state reactions of nanopowders resulted in heterogeneously transparent samples. Ceramics made by powders of other synthetic routes gave nontransparent ceramics due to porosity

  8. Positron Emission Tomography Imaging Using Radiolabeled Inorganic Nanomaterials

    Science.gov (United States)

    Sun, Xiaolian; Cai, Weibo; Chen, Xiaoyuan

    2015-01-01

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

  9. Potentials of positron emission tomography for regional cerebral blood flow evaluation

    International Nuclear Information System (INIS)

    Depresseux, J.C.

    1982-01-01

    A general overview of the potentials of positron emission tomography and of positron-emitting radiopharmaceuticals for the evaluation of regional cerebral blood flow is proposed and discussed. Specific characteristics of this technique are described, with special stress on conceptual and methodological implications. Four different approaches to the problem of the determination of cerebral blood flow are distinguished: trapping equilibrium methods, steady state equilibrium methods, clearance methods and convoluted kinetic methods [fr

  10. A high-resolution regional emission inventory of atmospheric mercury and its comparison with multi-scale inventories: a case study of Jiangsu, China

    Directory of Open Access Journals (Sweden)

    H. Zhong

    2016-12-01

    Full Text Available A better understanding of the discrepancies in multi-scale inventories could give an insight into their approaches and limitations as well as provide indications for further improvements; international, national, and plant-by-plant data are primarily obtained to compile those inventories. In this study we develop a high-resolution inventory of Hg emissions at 0.05°  ×  0.05° for Jiangsu, China, using a bottom-up approach and then compare the results with available global/national inventories. With detailed information on individual sources and the updated emission factors from field measurements applied, the annual Hg emissions of anthropogenic origin in Jiangsu in 2010 are estimated at 39 105 kg, of which 51, 47, and 2 % were Hg0, Hg2+, and Hgp, respectively. This provincial inventory is thoroughly compared to three downscaled national inventories (NJU, THU, and BNU and two global ones (AMAP/UNEP and EDGARv4.tox2. Attributed to varied methods and data sources, clear information gaps exist in multi-scale inventories, leading to differences in the emission levels, speciation, and spatial distributions of atmospheric Hg. The total emissions in the provincial inventory are 28, 7, 19, 22, and 70 % larger than NJU, THU, BNU, AMAP/UNEP, and EDGARv4.tox2, respectively. For major sectors, including power generation, cement, iron and steel, and other coal combustion, the Hg contents (HgC in coals/raw materials, abatement rates of air pollution control devices (APCDs and activity levels are identified as the crucial parameters responsible for the differences in estimated emissions between inventories. Regarding speciated emissions, a larger fraction of Hg2+ is found in the provincial inventory than national and global inventories, resulting mainly from the results by the most recent domestic studies in which enhanced Hg2+ were measured for cement and iron and steel plants. Inconsistent information on large power and industrial plants is

  11. Chemical characterization of long-range transport biomass burning emissions to the Himalayas: insights from high-resolution aerosol mass spectrometry

    Science.gov (United States)

    Zhang, Xinghua; Xu, Jianzhong; Kang, Shichang; Liu, Yanmei; Zhang, Qi

    2018-04-01

    An intensive field measurement was conducted at a remote, background, high-altitude site (Qomolangma Station, QOMS, 4276 m a.s.l.) in the northern Himalayas, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) along with other collocated instruments. The field measurement was performed from 12 April to 12 May 2016 to chemically characterize the high time-resolved submicron particulate matter (PM1) and obtain the dynamic processes (emissions, transport, and chemical evolution) of biomass burning (BB), frequently transported from South Asia to the Himalayas during pre-monsoon season. Overall, the average (±1σ) PM1 mass concentration was 4.44 (±4.54) µg m-3 for the entire study, which is comparable with those observed at other remote sites worldwide. Organic aerosol (OA) was the dominant PM1 species (accounting for 54.3 % of total PM1 on average) followed by black carbon (BC) (25.0 %), sulfate (9.3 %), ammonium (5.8 %), nitrate (5.1 %), and chloride (0.4 %). The average size distributions of PM1 species all peaked at an overlapping accumulation mode (˜ 500 nm), suggesting that aerosol particles were internally well-mixed and aged during long-range transport. Positive matrix factorization (PMF) analysis on the high-resolution organic mass spectra identified three distinct OA factors, including a BB-related OA (BBOA, 43.7 %), a nitrogen-containing OA (NOA, 13.9 %) and a more-oxidized oxygenated OA (MO-OOA, 42.4 %). Two polluted episodes with enhanced PM1 mass loadings and elevated BBOA contributions from the west and southwest of QOMS during the study were observed. A typical BB plume was investigated in detail to illustrate the chemical evolution of aerosol characteristics under distinct air mass origins, meteorological conditions, and atmospheric oxidation processes.

  12. Preclinical evaluation of a positron emitting progestin ([18F]fluoro-16 alpha-methyl-19-norprogesterone) for imaging progesterone receptor positive tumours with positron emission tomography

    NARCIS (Netherlands)

    Verhagen, Aalt; Luurtsema, Gert; PESSER, JW; DEGROOT, TJ; OOSTERHUIS, JW; Vaalburg, Willem; Wouda, S.

    Three 21-fluoro-progestins were investigated as potential imaging agents for the in vivo assessment of human progesterone receptor positive neoplasms with positron emission tomography. In competitive binding assays these compounds demonstrated high specificity, competing only for progesterone

  13. Positron emission tomography of malignant tumours at head and neck. Evaluation of the diagnostic value of positron emission tomography by comparison with computed tomography

    International Nuclear Information System (INIS)

    Kettler, Nele

    2011-01-01

    Imaging methods for early, accurate diagnosis and aftercare of malignant growths is currently one of the most important research topics. The objective of this thesis is to evaluate the diagnostic value of FDG-positron emission tomography by comparison with computed tomography for patients with squamous cell carcinoma, malignant melanoma or sarcoma at head and neck. Measurement criteria are sensitivity and specificity. A retrospective evaluation of 100 examinations on 85 patients of University clinic Aachen was performed. The examination reports were supported by reports from histology, positron emission tomography and computed tomography. In each case, the histological results were assumed to provide a reliable benchmark. Sensitivity and specificity for the primary tumour site, metastatic lymphatic nodes and defined anatomic structures were compared across all patients. Comparisons were also performed on sub groups separated by gender, cancer type and the time and frequency at which tumours arose. The statistic analysis was done with MedCalc. Results: The results for sensitivity and specificity of the primary tumour site were 86.42% and 42.86%, and 64.71% and 66.07%, for positron emission tomography and computed tomography respectively. The results for the lymphatic nodes were 51.52% and 92.86% and 64.71% and 66.07%. When the constituent anatomic structures were evaluated separately, the specificity was significantly higher. The separation by gender showed no difference. Because the classification by tumor type resulted in samples that were of varying size, a comparison was difficult. For the diagnosis of primary tumours, the examination with positron emission tomography was superior, whereas computed tomography proved more effective for the diagnosis of recurrent tumours. For the diagnosis of the main tumour site, both methods were shown to be equally suitable. For the assessment of lymphatic nodes, positron emission tomography was superior to computed tomography

  14. High Resolution Elevation Contours

    Data.gov (United States)

    Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

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

    International Nuclear Information System (INIS)

    Setty, B.; Blake, M.A.; Holalkere, N.S.; Blaszkowsky, L.S.; Fischman, A.

    2006-01-01

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

  16. Homotopic non-local regularized reconstruction from sparse positron emission tomography measurements

    International Nuclear Information System (INIS)

    Wong, Alexander; Liu, Chenyi; Wang, Xiao Yu; Fieguth, Paul; Bie, Hongxia

    2015-01-01

    Positron emission tomography scanners collect measurements of a patient’s in vivo radiotracer distribution. 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, and the tomograms must be reconstructed from projections. The reconstruction of tomograms from the acquired PET data is an inverse problem that requires regularization. The use of tightly packed discrete detector rings, although improves signal-to-noise ratio, are often associated with high costs of positron emission tomography systems. Thus a sparse reconstruction, which would be capable of overcoming the noise effect while allowing for a reduced number of detectors, would have a great deal to offer. In this study, we introduce and investigate the potential of a homotopic non-local regularization reconstruction framework for effectively reconstructing positron emission tomograms from such sparse measurements. Results obtained using the proposed approach are compared with traditional filtered back-projection as well as expectation maximization reconstruction with total variation regularization. A new reconstruction method was developed for the purpose of improving the quality of positron emission tomography reconstruction from sparse measurements. We illustrate that promising reconstruction performance can be achieved for the proposed approach even at low sampling fractions, which allows for the use of significantly fewer detectors and have the potential to reduce scanner costs

  17. Use of positron emission tomography in colorectal cancer; Uso de la tomografia de emision de positrones en el cancer colorrectal

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez E, Patricio; Jofre E, Josefina; Massardo V, Teresa; Humeres, Pamela; Canessa G, Jose; Sierralta C, Paulina [Hospital Militar de Santiago, Medicina Nuclear, Centro PET de Imagenes Moleculares, Santiago (Chile)

    2002-07-01

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

  18. Dynamic positron emission tomography for study of cerebral hemodynamics in a cross section of the head using positron-emitting 68Ga-EDTA and 77Kr

    International Nuclear Information System (INIS)

    Yamamoto, Y.L.; Thompson, C.J.; Meyer, E.; Robertson, J.S.; Feindel, W.

    1977-01-01

    Dynamic positron emission tomographic studies were performed on over 120 patients with occlusive cerebrovascular disease, arteriovenous malformations, and brain tumors, using the positron section scanner, consisting of a ring of 32 scintillation detectors. The radiopharmaceuticals were nondiffusible 68 Ga-EDTA for transit time and uptake studies and the diffusible tracer, 77 Kr, for quantitative regional cerebral blood flow studies in every square centimeter of the cross section of the head. The results of dynamic positron emission tomography in correlation with the results from the gamma scintillation camera dynamic studies and computed tomography (CT) scans are discussed

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

    International Nuclear Information System (INIS)

    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.

    1994-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-04-01

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

  1. Defining a radiotherapy target with positron emission tomography

    International Nuclear Information System (INIS)

    Black, Quinten C.; Grills, Inga S.; Kestin, Larry L.; Wong, Ching-Yee O.; Wong, John W.; Martinez, Alvaro A.; Yan Di

    2004-01-01

    Purpose: F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is now considered the most accurate clinical staging study for non-small-cell lung cancer (NSCLC) and is also important in the staging of multiple other malignancies. Gross tumor volume (GTV) definition for radiotherapy, however, is typically based entirely on computed tomographic data. We performed a series of phantom studies to determine an accurate and uniformly applicable method for defining a GTV with FDG-PET. Methods and materials: A model-based method was tested by a phantom study to determine a threshold, or unique cutoff of standardized uptake value based on body weight (standardized uptake value [SUV]) for FDG-PET based GTV definition. The degree to which mean target SUV, background FDG concentration, and target volume influenced that GTV definition were evaluated. A phantom was constructed consisting of a 9.0-L cylindrical tank. Glass spheres with volumes ranging from 12.2 to 291.0 cc were suspended within the tank, with a minimum separation of 4 cm between the edges of the spheres. The sphere volumes were selected based on the range of NSCLC patient tumor volumes seen in our clinic. The tank and spheres were filled with a variety of known concentrations of FDG in several experiments and then scanned using a General Electric Advance PET scanner. In the initial experiment, six spheres with identical volumes were filled with varying concentrations of FDG (mean SUV 1.85 ∼ 9.68) and suspended within a background bath of FDG at a similar concentration to that used in clinical practice (0.144 μCi/mL). The second experiment was identical to the first, but was performed at 0.144 and 0.036 μCi/mL background concentrations to determine the effect of background FDG concentration on sphere definition. In the third experiment, six spheres with volumes of 12.2 to 291.0 cc were filled with equal concentrations of FDG and suspended in a standard background FDG concentration of 0.144

  2. Molecular Imaging of Transporters with Positron Emission Tomography

    Science.gov (United States)

    Antoni, Gunnar; Sörensen, Jens; Hall, Håkan

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

  3. Role and impact of [18F]-fluorodeoxyglucose positron emission tomography in recurrent breast cancer

    International Nuclear Information System (INIS)

    Grahek, D.; Montravers, F.; Aide, N.; Kerrou, K.; Talbot, J.N.

    2004-01-01

    [18F]-fluorodeoxyglucose positron emission tomography is widely used in oncology to detect malignant tissue, assess the extent of the disease and follow up treatment. In breast cancer, recurrence detection seems to be the leading indication of [18F] fluorodeoxyglucose positron emission tomography. This review, including recent publications, aims to evaluate its role to detect the recurrent malignant. tissue when tumour marker levels are isolatedly rising and to evaluate the extent of-the disease. The first impact studies reveal its important role in the management of the patients suspected of breast cancer recurrence. (author)

  4. Using JPSS VIIRS Fire Radiative Power Data to Forecast Biomass Burning Emissions and Smoke Transport by the High Resolution Rapid Refresh Model

    Science.gov (United States)

    Ahmadov, R.; Grell, G. A.; James, E.; Alexander, C.; Stewart, J.; Benjamin, S.; McKeen, S. A.; Csiszar, I. A.; Tsidulko, M.; Pierce, R. B.; Pereira, G.; Freitas, S. R.; Goldberg, M.

    2017-12-01

    We present a new real-time smoke modeling system, the High Resolution Rapid Refresh coupled with smoke (HRRR-Smoke), to simulate biomass burning (BB) emissions, plume rise and smoke transport in real time. The HRRR is the NOAA Earth System Research Laboratory's 3km grid spacing version of the Weather Research and Forecasting (WRF) model used for weather forecasting. Here we make use of WRF-Chem (the WRF model coupled with chemistry) and simulate fine particulate matter (smoke) emissions emitted by BB. The HRRR-Smoke modeling system ingests fire radiative power (FRP) data from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the Suomi National Polar-orbiting Partnership (S-NPP) satellite to calculate BB emissions. The FRP product is based on processing 750m resolution "M" bands. The algorithms for fire detection and FRP retrieval are consistent with those used to generate the MODIS fire detection data. For the purpose of ingesting VIIRS fire data into the HRRR-Smoke model, text files are generated to provide the location and detection confidence of fire pixels, as well as FRP. The VIIRS FRP data from the text files are processed and remapped over the HRRR-Smoke model domains. We process the FRP data to calculate BB emissions (smoldering part) and fire size for the model input. In addition, HRRR-Smoke uses the FRP data to simulate the injection height for the flaming emissions using concurrently simulated meteorological fields by the model. Currently, there are two 3km resolution domains covering the contiguous US and Alaska which are used to simulate smoke in real time. In our presentation, we focus on the CONUS domain. HRRR-Smoke is initialized 4 times per day to forecast smoke concentrations for the next 36 hours. The VIIRS FRP data, as well as near-surface and vertically integrated smoke mass concentrations are visualized for every forecast hour. These plots are provided to the public via the HRRR-Smoke web-page: https

  5. Anthropogenic and volcanic emission impacts on SO2 dynamics and acid rain profiles. Numerical study using WRF-Chem in a high-resolution modeling

    Science.gov (United States)

    Vela, A. V.; González, C. M.; Ynoue, R.; Rojas, N. Y.; Aristizábal, B. H.; Wahl, M.

    2017-12-01

    Eulerian 3-D chemistry transport models (CTM) have been widely used for the study of air quality in urban environments, becoming an essential tool for studying the impacts and dynamics of gases and aerosols on air quality. However, their use in Colombia is scarce, especially in medium-sized cities, which are experimenting a fast urban growth, increasing the risk associated with possible air pollution episodes. In the densely populated medium-sized Andean city of Manizales, Colombia - a city located on the western slopes of the central range of the Andes (urban population 368000; 2150 m.a.s.l), there is an influence of the active Nevado del Ruiz volcano, located 28 km to the southwest. This natural source emits daily gas and particle fluxes, which could influence the atmospheric chemistry of the city and neighboring towns. Hence, the zone presents a unique combination of anthropogenic and volcanic sulfur gas emissions, which affects SO2 dynamics in the urban area, influencing also in the formation of acid rain phenomenon in the city. Therefore, studies analyzing the relative contribution of anthropogenic and volcanic emission could contribute with a deep understanding about causes and dynamics of both acid rain phenomenon and ambient SO2 levels in Manizales. This work aimed to analyze the influence of anthropogenic (on-road vehicular and industrial point-sources) and volcanic sulfur emissions in SO2 atmospheric chemistry dynamics, evaluating its possible effects on acid rain profiles. Ambient SO2 levels and day-night rain samples were measured and used to analyze results obtained from the application of the fully-coupled on-line WRF-Chem model. Two high-resolution simulations were performed during two dry and wet one-week periods in 2015. Analysis of SO2 dispersion patterns and comparison with SO2 observations in the urban area were performed for three different scenarios in which natural and anthropogenic emissions were simulated separately. Results suggest that

  6. Modeling real-world fuel consumption and carbon dioxide emissions with high resolution for light-duty passenger vehicles in a traffic populated city

    International Nuclear Information System (INIS)

    Zhang, Shaojun; Wu, Ye; Un, Puikei; Fu, Lixin; Hao, Jiming

    2016-01-01

    Modeling fuel consumption of light-duty passenger vehicles has created substantial concerns due to the uncertainty from real-world operating conditions. Macao is world-renowned for its tourism industry and high population density. An empirical model is developed to estimate real-world fuel consumption and carbon dioxide emissions for gasoline-powered light-duty passenger vehicles in Macao by considering local fleet configuration and operating conditions. Thanks to increasingly stringent fuel consumption limits in vehicle manufacturing countries, estimated type-approval fuel consumption for light-duty passenger vehicles in Macao by model year was reduced from 7.4 L/100 km in 1995 to 5.9 L/100 km in 2012, although a significant upsizing trend has considerably offset potential energy-saving benefit. However, lower driving speed and the air-conditioning usage tend to raise fleet-average fuel consumption and carbon dioxide emission factors, which are estimated to be 10.1 L/100 km and 240 g/km in 2010. Fleet-total fuel consumption and carbon dioxide emissions are modeled through registered vehicle population-based and link-level traffic demand approaches and the results satisfactorily coincide with the historical record of fuel sales in Macao. Temporal and spatial variations in fuel consumption and carbon dioxide emissions from light-duty passenger vehicles further highlight the importance of effective traffic management in congested areas of Macao. - Highlights: • A fuel consumption model is developed for Macao's light-duty passenger cars. • Increased vehicle size partially offset energy benefit from tightened fuel consumption standard. • Lower speed and use of air-conditioning greatly increase fuel use of Macao light-duty passenger cars. • A high resolution inventory of fuel use and carbon dioxide emissions is built with link-level traffic data. • Policy suggestions are provided to mitigate fuel use in a traffic populated city.

  7. A BGO detector for Positron Emission Profiling in catalysts

    International Nuclear Information System (INIS)

    Mangnus, A.V.G.; Cunningham, R.H.; Santen, R.A. van; Voigt, M.J.A. de

    1995-01-01

    As part of a project to study the reaction kinetics in catalysts, a detector system has been designed and built. The detector will measure in one dimension the activity distribution of positron emitters in catalyst reactors under operational conditions as a function of time. The detector consists of two arrays of ten BGO crystals each and has the flexibility to measure with high sensitivity the activity profile in various reactor sizes; the position resolution that can be reached is 3 mm. (orig.)

  8. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration.

    Science.gov (United States)

    Converse, Alexander K; Ahlers, Elizabeth O; Bryan, Tom W; Hetue, Jackson D; Lake, Katherine A; Ellison, Paul A; Engle, Jonathan W; Barnhart, Todd E; Nickles, Robert J; Williams, Paul H; DeJesus, Onofre T

    2015-01-01

    Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [(18)F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modeling of fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. After initiation of administration at the bisected leaf stalk, [(18)F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.

  9. Fluorodeoxyglucose and C-Choline positron emission tomography for distinction of metastatic plexopathy and neuritis : a case report

    NARCIS (Netherlands)

    Bartels, Anna L.; Zeebregts, Clark J; Enting, Roeline; Slart, Riemer Hja

    2009-01-01

    INTRODUCTION: Fluorodeoxyglucose positron emission tomography scanning has an established role in the diagnostic work-up of many malignant diseases and also in the evaluation of cancer treatment response. Fluorodeoxyglucose positron emission tomography may, however be non-specific as infectious

  10. High-resolution multi-slice PET

    International Nuclear Information System (INIS)

    Yasillo, N.J.; Chintu Chen; Ordonez, C.E.; Kapp, O.H.; Sosnowski, J.; Beck, R.N.

    1992-01-01

    This report evaluates the progress to test the feasibility and to initiate the design of a high resolution multi-slice PET system. The following specific areas were evaluated: detector development and testing; electronics configuration and design; mechanical design; and system simulation. The design and construction of a multiple-slice, high-resolution positron tomograph will provide substantial improvements in the accuracy and reproducibility of measurements of the distribution of activity concentrations in the brain. The range of functional brain research and our understanding of local brain function will be greatly extended when the development of this instrumentation is completed

  11. High resolution solar observations

    International Nuclear Information System (INIS)

    Title, A.

    1985-01-01

    Currently there is a world-wide effort to develop optical technology required for large diffraction limited telescopes that must operate with high optical fluxes. These developments can be used to significantly improve high resolution solar telescopes both on the ground and in space. When looking at the problem of high resolution observations it is essential to keep in mind that a diffraction limited telescope is an interferometer. Even a 30 cm aperture telescope, which is small for high resolution observations, is a big interferometer. Meter class and above diffraction limited telescopes can be expected to be very unforgiving of inattention to details. Unfortunately, even when an earth based telescope has perfect optics there are still problems with the quality of its optical path. The optical path includes not only the interior of the telescope, but also the immediate interface between the telescope and the atmosphere, and finally the atmosphere itself

  12. Chemical characterization of long-range transport biomass burning emissions to the Himalayas: insights from high-resolution aerosol mass spectrometry

    Directory of Open Access Journals (Sweden)

    X. Zhang

    2018-04-01

    Full Text Available An intensive field measurement was conducted at a remote, background, high-altitude site (Qomolangma Station, QOMS, 4276 m a.s.l. in the northern Himalayas, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS along with other collocated instruments. The field measurement was performed from 12 April to 12 May 2016 to chemically characterize the high time-resolved submicron particulate matter (PM1 and obtain the dynamic processes (emissions, transport, and chemical evolution of biomass burning (BB, frequently transported from South Asia to the Himalayas during pre-monsoon season. Overall, the average (±1σ PM1 mass concentration was 4.44 (±4.54 µg m−3 for the entire study, which is comparable with those observed at other remote sites worldwide. Organic aerosol (OA was the dominant PM1 species (accounting for 54.3 % of total PM1 on average followed by black carbon (BC (25.0 %, sulfate (9.3 %, ammonium (5.8 %, nitrate (5.1 %, and chloride (0.4 %. The average size distributions of PM1 species all peaked at an overlapping accumulation mode (∼ 500 nm, suggesting that aerosol particles were internally well-mixed and aged during long-range transport. Positive matrix factorization (PMF analysis on the high-resolution organic mass spectra identified three distinct OA factors, including a BB-related OA (BBOA, 43.7 %, a nitrogen-containing OA (NOA, 13.9 % and a more-oxidized oxygenated OA (MO-OOA, 42.4 %. Two polluted episodes with enhanced PM1 mass loadings and elevated BBOA contributions from the west and southwest of QOMS during the study were observed. A typical BB plume was investigated in detail to illustrate the chemical evolution of aerosol characteristics under distinct air mass origins, meteorological conditions, and atmospheric oxidation processes.

  13. Fast iterative segmentation of high resolution medical images

    International Nuclear Information System (INIS)

    Hebert, T.J.

    1996-01-01

    Various applications in positron emission tomography (PET), single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) require segmentation of 20 to 60 high resolution images of size 256x256 pixels in 3-9 seconds per image. This places particular constraints on the design of image segmentation algorithms. This paper examines the trade-offs in segmenting images based on fitting a density function to the pixel intensities using curve-fitting versus the maximum likelihood method. A quantized data representation is proposed and the EM algorithm for fitting a finite mixture density function to the quantized representation for an image is derived. A Monte Carlo evaluation of mean estimation error and classification error showed that the resulting quantized EM algorithm dramatically reduces the required computation time without loss of accuracy

  14. Intrinsic spatial resolution limitations due to differences between positron emission position and annihilation detection localization

    International Nuclear Information System (INIS)

    Perez, Pedro; Malano, Francisco; Valente, Mauro

    2012-01-01

    Since its successful implementation for clinical diagnostic, positron emission tomography (PET) represents the most promising medical imaging technique. The recent major growth of PET imaging is mainly due to its ability to trace the biologic pathways of different compounds in the patient's body, assuming the patient can be labeled with some PET isotope. Regardless of the type of isotope, the PET imaging method is based on the detection of two 511-keV gamma photons being emitted in opposite directions, with almost 180 deg between them, as a consequence of electron-positron annihilation. Therefore, this imaging method is intrinsically limited by random uncertainties in spatial resolutions, related with differences between the actual position of positron emission and the location of the detected annihilation. This study presents an approach with the Monte Carlo method to analyze the influence of this effect on different isotopes of potential implementation in PET. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Pellat, J; Hommel, M

    1987-06-18

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

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

    International Nuclear Information System (INIS)

    Pellat, J.; Hommel, M.

    1987-01-01

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

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

    International Nuclear Information System (INIS)

    Gundacker, S.

    2014-01-01

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

  18. MRI and {sup 18}F-fluorodeoxyglucose positron emission tomography in hemimegalencephaly

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, K.T.; Liebig, T.; Hosten, N. [Departments of Radiology and Nuclear Medicine, Virchow-Klinikum, Charite, Berlin (Germany); Amthauer, H.; Farahati, J.; Felix, R. [Departments of Radiology and Nuclear Medicine, Virchow-Klinikum, Charite, Berlin (Germany); PET-Centre Berlin, Virchow-Klinikum, Charite, Humboldt-University, Berlin (Germany); Etou, A.; Lehmann, T.N. [Department of Neurosurgery, Virchow-Klinikum, Charite, Humboldt-University, Berlin (Germany)

    2000-10-01

    We report hemimegalencephaly in a 44-year-old woman with mental retardation, epilepsy and a mild hemiparesis. In addition to typical findings on MRI, 2-deoxy-2[{sup 18}F]fluorodeoxyglucose positron-emission tomography (PET) demonstrated glucose hypometabolism of the affected hemisphere. The results of PET have been coregistered with morphological information from the MRI studies by image fusion. (orig.)

  19. Synthesis and biodistribution of [C-11]procaterol, a beta(2)-adrenoceptor agonist for positron emission tomography

    NARCIS (Netherlands)

    Visser, TJ; van der Wouden, EA; van Waarde, A; Doze, P; Elsinga, PH; Vaalburg, W

    The potent, subtype-selective radioligand (+/-)-erythro-5-(1-hydroxy-2-[C-11]isopropyl-aminobutyl)-8-hydroxy-carbostyril ([C-11]procaterol) was synthesized and evaluated for visualization of pulmonary beta(2)-adrenoceptors with positron emission tomography (PET). Procaterol was labelled by reductive

  20. Positron emission CT and X-ray CT findings in chronic obstructive pulmonary diseases

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yoshikazu; Murata, Kiyoshi; Ito, Harumi; Senda, Michio; Yonekura, Yoshiharu; Konishi, Junji; Nishimura, Koichi; Izumi, Takahide; Oshima, Shunsaku

    1987-08-01

    Positron emission CT and X-ray CT were performed in fifteen patients with emphysema confirmed SAB and twelve patients with clinical DPB. In patients with emphysema, 20 of 36 areas showed a central pattern and their perfusion scintigrams showed stripe-signs. On the other hand, the patients with DPB showed outer layer progression of the disease.

  1. Characterization of positron emission tomography hypoxia tracer uptake and tissue oxygenation via electrochemical modeling

    NARCIS (Netherlands)

    Bowen, S.R.; Kogel, A.J. van der; Nordsmark, M.; Bentzen, S.M.; Jeraj, R.

    2011-01-01

    PURPOSE: Unique uptake and retention mechanisms of positron emission tomography (PET) hypoxia tracers make in vivo comparison between them challenging. Differences in imaged uptake of two common hypoxia radiotracers, [(61)Cu]Cu-ATSM and [(18)F]FMISO, were characterized via computational modeling to

  2. 77 FR 8262 - Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Science.gov (United States)

    2012-02-14

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-D-0081] Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug...

  3. Monitoring variables affecting positron emission tomography measurements of cerebral blood flow in anaesthetized pigs

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen; Zois, Nora Elisabeth; Simonsen, Mette

    Background: Positron emission tomography (PET) imaging of anaesthetised pig brains is a useful tool in neuroscience. Stable cerebral blood flow (CBF) is essential for PET, since variations can affect the kinetics of several radiotracers. However, the impact of physiological factors regulating CBF...

  4. Early positron emission tomography response-adapted treatment in stage I and II hodgkin lymphoma

    DEFF Research Database (Denmark)

    André, Marc P.E.; Girinsky, Théodore; Federico, Massimo

    2017-01-01

    Purpose Patients who receive combined modality treatment for stage I and II Hodgkin lymphoma (HL) have an excellent outcome. Early response evaluation with positron emission tomography (PET) scan may improve selection of patients who need reduced or more intensive treatments. Methods We performed...

  5. A positron emission tomography study of wind-up pain in chronic postherniotomy pain

    DEFF Research Database (Denmark)

    Kupers, Ron; Lonsdale, Markus Georg; Aasvang, Eske Kvanner

    2011-01-01

    -induced wind-up pain in neuropathic pain patients. We therefore used positron emission tomography (PET) to investigate the cerebral response pattern of mechanical wind-up pain in a homogenous group of 10 neuropathic pain patients with long-standing postherniotomy pain in the groin area. Patients were scanned...

  6. Positron emission tomography in the diagnosis and staging of lung cancer

    DEFF Research Database (Denmark)

    Fischer, B M; Mortensen, J; Højgaard, L

    2001-01-01

    positron emission tomography (PET) and gamma-camera PET in the diagnostic investigation of non-small-cell lung cancer (NSCLC). A systematic literature search was carried out in the MEDLINE and EMBASE databases and the Cochrane Controlled Trials Register. We identified 55 original works on the diagnostic...

  7. Hypoxia positron emission tomography imaging: combining information on perfusion and tracer retention to improve hypoxia specificity

    DEFF Research Database (Denmark)

    Busk, Morten; Munk, Ole L; Jakobsen, Steen S

    2017-01-01

    BACKGROUND: Static positron emission tomography (PET) allows mapping of tumor hypoxia, but low resolution and slow tracer retention/clearance results in poor image contrast and the risk of missing areas where hypoxic cells and necrosis are intermixed. Fully dynamic PET may improve accuracy but scan...

  8. Positron emission tomography in the follow-up of cutaneous malignant melanoma patients

    DEFF Research Database (Denmark)

    Danielsen, Maria; Højgaard, Liselotte; Kjær, Andreas

    2014-01-01

    node involvement and distant metastases, accentuating the importance of close surveillance to identify disease progression at an early stage, and thereby detect recurrences amenable to treatment. Positron emission tomography (PET) has already been proven useful in the staging of CMM, but the utility...

  9. 18F-fluorodeoxyglucose positron emission tomography predicts survival of patients with neuroendocrine tumors

    DEFF Research Database (Denmark)

    Binderup, Tina; Knigge, Ulrich; Loft, Annika

    2010-01-01

    PURPOSE: (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is currently not used on a routine basis for imaging of neuroendocrine (NE) tumors. The aim of this study was to investigate the prognostic value of FDG-PET in patients with NE tumors. EXPERIMENTAL DESIGN: Ninety...

  10. Monitoring of herpes simplex virus thymidine kinase enzyme activity using positron emission tomography

    NARCIS (Netherlands)

    Hospers, GAP; Calogero, Anna; van Waarde, A; Doze, P; Vaalburg, W; Mulder, NH; de Vries, EFJ

    2000-01-01

    9-[(1-[F-18]Fluoro-3-hydroxy-2-propoxy)methyl]guanine ([F-18]FHPG) wasevaluated as a tracer for noninvasive positron emission tomography (PET) imaging of herpes simplex virus type 1 thymidine kinase (HSV-tk) gene expression. C6 rat glioma cells with and without the HSV-tk gene were incubated with

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

    NARCIS (Netherlands)

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

    2009-01-01

    Objective: 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.

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

    International Nuclear Information System (INIS)

    Romero, J.A.; Kim, E.E.; Tresukosol, D.; Kudelka, A.P.; Edwards, C.L.; Kavanagh, J.J.

    1995-01-01

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

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

    International Nuclear Information System (INIS)

    Lopez D, F.A.

    2005-01-01

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

  14. Cobalt-55 positron emission tomography in traumatic brain injury : A pilot study

    NARCIS (Netherlands)

    Jansen, HML; vanderNaalt, J; vanZomeren, AH; Paans, AMJ; VeenmavanderDuin, L; Hew, JM; Pruim, J; Minderhoud, JM; Korf, J

    Traumatic brain injury is usually assessed with the Glasgow coma scale (GCS), CT, or MRI. After such injury, the injured brain tissue is characterised by calcium mediated neuronal damage and inflammation. Positron emission tomography with the isotope cobalt-55 (Go-PET) as a calcium tracer enables

  15. Statistical properties of compartmental model parameters extracted from dynamic positron emission tomography experiments

    International Nuclear Information System (INIS)

    Mazoyer, B.M.; Huesman, R.H.; Budinger, T.F.; Knittel, B.L.

    1986-01-01

    Over the past years a major focus of research in physiologic studies employing tracers has been the computer implementation of mathematical methods of kinetic modeling for extracting the desired physiological parameters from tomographically derived data. A study is reported of factors that affect the statistical properties of compartmental model parameters extracted from dynamic positron emission tomography (PET) experiments

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

    International Nuclear Information System (INIS)

    Zade, Anand; Ahire, Archana; Shetty, Shishir; Rai, Sujith; Bokka, Rajashekharrao; Velumani, Arokiaswamy; Kabnurkar, Rasika

    2015-01-01

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

  17. Characterization of hepatic tumors using [11C]metomidate through positron emission tomography

    DEFF Research Database (Denmark)

    Roivainen, Anne; Naum, Alexandru; Nuutinen, Heikki

    2013-01-01

    ABSTRACT: BACKGROUND: Using positron emission tomography (PET), we compared two tracers, [11C]metomidate ([11C]MTO) and [11C]acetate ([11C]ACE), for the characterization of hepatic tumors. METHODS: Thirty-three patients underwent PET with [11C]MTO and [11C]ACE and magnetic resonance imaging (MRI...

  18. Investigating Serotonergic Function Using Positron Emission Tomography: Overview and Recent Findings

    NARCIS (Netherlands)

    Veltman, D.J.; Ruhe, H.G.; Booij, J.

    2010-01-01

    Mono-aminergic neurotransmitters, in particular serotonin (5-HT), are involved in regulating a large number of psychological and physiological functions, and abnormal 5-HT transmission has been implicated in a wide variety of neuropsychiatric disorders. Positron emission tomography (PET) is a

  19. A Monte Carlo simulation of the possible use of Positron Emission Tomography in proton radiotherapy

    International Nuclear Information System (INIS)

    Del Guerra, Alberto; Di Domenico, Giovanni; Gambaccini, Mauro; Marziani, Michele

    1994-01-01

    We have used the Monte Carlo technique to evaluate the applicability of Positron Emission Tomography to in vivo dosimetry for proton radiotherapy. A fair agreement has been found between Monte Carlo results and experimental data. The simulation shows that PET can be useful especially for in vivo Bragg's peak localization. ((orig.))

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  2. Diffuse nesidioblastosis diagnosed on a Ga-68 DOTATATE positron emission tomography/computerized tomography

    International Nuclear Information System (INIS)

    Arun, Sasikumar; Mittal, Bhagwant Rai; Shukla, Jaya; Bhattacharya, Anish; Kumar, Praveen

    2013-01-01

    The authors describe a 50 days old pre-term infant with persistent hyperinsulinemic hypoglycemia of infancy in whom 68 Ga DOTATATE positron emission tomography/computerized tomography scan showed diffusely increased tracer uptake in the entire pancreas with no abnormal tracer uptake anywhere else in the body, suggestive of a diffuse variant of nesidioblastosis. (author)

  3. Fluorodeoxyglucose-based positron emission tomography imaging to monitor drug responses in hematological tumors

    NARCIS (Netherlands)

    Newbold, Andrea; Martin, Ben P.; Cullinane, Carleen; Bots, Michael

    2014-01-01

    Positron emission tomography (PET) can be used to monitor the uptake of the labeled glucose analog fluorodeoxyglucose (¹⁸F-FDG), a process that is generally believed to reflect viable tumor cell mass. The use of ¹⁸F-FDG PET can be helpful in documenting over time the reduction in tumor mass volume

  4. Positron emission medical measurements with accelerated radioactive ion beams

    International Nuclear Information System (INIS)

    Llacer, J.

    1988-01-01

    This paper reviews in some detail the process by which a heavy ion accelerator can be used to inject positron emitting radioactive particles into a human body for a range of possible medical measurements. The process of radioactive beam generation and injection is described, followed by a study of the relationship between activity that can be injected versus dose to the patient as a function of which of the positron emitting ions is used. It is found that 6 C 10 and 10 Ne 19 are the two isotopes that appear more promising for injection into humans. The design considerations for a non-tomographic instrument to obtain images from beam injections are outlined and the results of 10 Ne 19 preliminary measurements with human phantoms and actual patients for the determination of end-of-range of cancer therapy ion beams is reported. Accuracies in the order of ±1 mm in the measurements of stopping point of a therapy beam with safe doses to the patient are reported. The paper concludes with a simple analysis of requirements to extend the technique to on-line verification of cancer treatment and to nuclear medicine research and diagnostics measurements. 17 refs.; 16 figs.; 3 tabs

  5. The review of myocardial positron emission computed tomography and positron imaging by gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, Tohru [Tokyo Univ. (Japan). Faculty of Medicine

    1998-04-01

    To measure myocardial blood flow, Nitrogen-13 ammonia, Oxygen-15 water, Rubidium-82 and et al. are used. Each has merit and demerit. By measuring myocardial coronary flow reserve, the decrease of flow reserve during dipyridamole in patients with hypercholesterolemia or diabetes mellitus without significant coronary stenosis was observed. The possibility of early detection of atherosclerosis was showed. As to myocardial metabolism, glucose metabolism is measured by Fluorine-18 fluorodeoxyglucose (FDG), and it is considered as useful for the evaluation of myocardial viability. We are using FDG to evaluate insulin resistance during insulin clamp in patients with diabetes mellitus by measuring glucose utilization rate of myocardium and skeletal muscle. FFA metabolism has been measured by {sup 11}C-palmitate, but absolute quantification has not been performed. Recently the method for absolute quantification was reported, and new radiopharmaceutical {sup 18}F-FTHA was reported. Oxygen metabolism has been estimated by {sup 11}C-acetate. Myocardial viability, cardiac efficiency was evaluated by oxygen metabolism. As to receptor or sympathetic nerve end, cardiac insufficiency or cardiac transplantation was evaluated. Imaging of positron emitting radiopharmaceutical by gamma camera has been performed. Collimator method is clinically useful for cardiac imaging of viability study. (author). 54 refs.

  6. Positron emission tomography of hepatic first-pass metabolism of ammonia in pig

    DEFF Research Database (Denmark)

    Keiding, S; Munk, O L; Roelsgaard, K

    2001-01-01

    Hepatic first-pass metabolism plays a key role in metabolic regulation and drug metabolism. Metabolic processes can be quantified in vivo by positron emission tomography scanning (PET). We wished to develop a PET technique to measure hepatic first-pass metabolism of ammonia. Seven anaesthetised...... pigs were given positron-labelled ammonia, (13)NH(3), into the portal vein and into the vena cava as successive 2-min infusions followed by 22-min dynamic liver scanning. Vena cava infusion data were used to account for recirculation of tracer and metabolites following the portal vein infusion...

  7. Positron emission tomography - a new technique for observing fluid behaviour in engineering systems

    International Nuclear Information System (INIS)

    Stewart, P.A.E.; Rogers, J.D.; Skelton, R.T.

    1988-01-01

    Positron emission tomography promises to become a powerful new technique for flow tracing and measurement within metal structures in general and operating engines in particular. The principles involved are outlined, and a mobile positron camera system being developed jointly by Rolls-Royce, Castrol, the University of Birmingham and the Rutherford-Appleton Laboratory of the SERC is described. Finally, illustrative examples of the camera's capability are presented drawn from its use to study lubricating fluid flow in the bearings of a Viper gas turbine engine on test up to 100% full power. (author)

  8. Three-dimensional imaging of hidden objects using positron emission backscatter

    International Nuclear Information System (INIS)

    Lee, Dongwon; Cowee, Misa; Fenimore, Ed; Galassi, Mark; Looker, Quinn; Mcneil, Wendy V.; Stonehill, Laura; Wallace, Mark

    2009-01-01

    Positron emission backscatter imaging is a technique for interrogation and three-dimensional (3-D) reconstruction of hidden objects when we only have access to the objects from one side. Using time-of-flight differences in detected direct and backscattered positron-emitted photons, we construct 3-D images of target objects. Recently at Los Alamos National Laboratory, a fully three-dimensional imaging system has been built and the experimental results are discussed in this paper. Quantitative analysis of images reconstructed in both two- and three-dimensions are also presented.

  9. Positron emission tomography in the newborn: extensive impairment of regional cerebral blood flow with intraventricular hemorrhage and hemorrhagic intracerebral involvement

    International Nuclear Information System (INIS)

    Volpe, J.J.; Herscovitch, P.; Perlman, J.M.; Raichle, M.E.

    1983-01-01

    Positron emission tomography (PET) now provides the capability of measuring regional cerebral blood flow with high resolution and little risk. In this study, we utilized PET in six premature infants (920 to 1,200 g) with major intraventricular hemorrhage and hemorrhagic intracerebral involvement to measure regional cerebral blood flow during the acute period (5 to 17 days of age). Cerebral blood flow was determined after intravenous injection of H 2 O, labeled with the positron-emitting isotope, 15 O. Findings were similar and dramatic in all six infants. In the area of hemorrhagic intracerebral involvement, little or no cerebral blood flow was detected. However, in addition, surprisingly, a marked two- to fourfold reduction in cerebral blood flow was observed throughout the affected hemisphere, well posterior and lateral to the intracerebral hematoma, including cerebral white matter and, to a lesser extent, frontal, temporal, and parietal cortex. In the one infant studied a second time, ie, at 3 months of age, the extent and severity of the decreased cerebral blood flows in the affected hemisphere were similar to those observed on the study during the neonatal period. At the three autopsies, the affected left hemisphere showed extensive infarction, corroborating the PET scans. These observations, the first demonstration of the use of PET in the determination of regional cerebral blood flow in the newborn, show marked impairments in regional cerebral blood flow in the hemisphere containing an apparently restricted intracerebral hematoma, indicating that the hemorrhagic intracerebral involvement is only a component of a much larger lesion, ischemic in basic nature, ie, an infarction. This large ischemic lesion explains the poor neurologic outcome in infants with intraventricular hemorrhage and hemorrhagic intracerebral involvement

  10. Application of position-sensitive detectors to positron imaging

    International Nuclear Information System (INIS)

    Yamashita, Takaji; Uchida, Hiroshi; Watanabe, Mitsuo; Omura, Tomohide

    1994-01-01

    Positron imaging including positron emission tomography (PET) is expected to be a promising tool for basic and clinical research, because it makes possible the study of regional chemistry within multiple organs of the body in living human beings and experimental animals. New schemes of high resolution block detectors have been developed to improve the performance of positron imaging systems, which employ small segments of bismuth germanate (BGO) arrays and position-sensitive photomultiplier tubes (PS-PMT). The coincidence detector resolution of less than 2.0 mm in full width at half maximum was achieved with the detectors, which is very close to the theoretical resolution limit in positron imaging. (author)

  11. Positron emission intensities in the decay of 64Cu, 76Br and 124I

    International Nuclear Information System (INIS)

    Qaim, S.M.; Bisinger, T.; Hilgers, K.; Nayak, D.; Coenen, H.H.

    2007-01-01

    The relatively long-lived positron emitters 64 Cu (t 1/2 = 12.7 h), 76 Br (t 1/2 = 16.2 h) and 124 I (t 1/2 = 4.18 d) are finding increasing applications in positron emission tomography (PET). For precise determination of their positron emission intensities, each radionuclide was prepared via a charged particle induced reaction in a ''no-carrier-added'' form and with high radionuclidic purity. It was then subjected to γ-ray and X-ray spectroscopy as well as to anticoincidence beta and γγ-coincidence counting. The positron emission intensities measured were: 64 Cu (17.8 ± 0.4)%, 76 Br (58.2 ± 1.9)% and 124 I (22.0 ± 0.5)%. The intensity of the weak 1346 keV γ-ray emitted in the decay of 64 Cu was determined as (0.54 ± 0.03)%. Some implications of the precisely determined nuclear data are discussed. (orig.)

  12. High resolution data acquisition

    Science.gov (United States)

    Thornton, Glenn W.; Fuller, Kenneth R.

    1993-01-01

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  13. ANL high resolution injector

    International Nuclear Information System (INIS)

    Minehara, E.; Kutschera, W.; Hartog, P.D.; Billquist, P.

    1985-01-01

    The ANL (Argonne National Laboratory) high-resolution injector has been installed to obtain higher mass resolution and higher preacceleration, and to utilize effectively the full mass range of ATLAS (Argonne Tandem Linac Accelerator System). Preliminary results of the first beam test are reported briefly. The design and performance, in particular a high-mass-resolution magnet with aberration compensation, are discussed. 7 refs., 5 figs., 2 tabs

  14. Ultra high resolution tomography

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  15. High resolution (transformers.

    Science.gov (United States)

    Garcia-Souto, Jose A; Lamela-Rivera, Horacio

    2006-10-16

    A novel fiber-optic interferometric sensor is presented for vibrations measurements and analysis. In this approach, it is shown applied to the vibrations of electrical structures within power transformers. A main feature of the sensor is that an unambiguous optical phase measurement is performed using the direct detection of the interferometer output, without external modulation, for a more compact and stable implementation. High resolution of the interferometric measurement is obtained with this technique (transformers are also highlighted.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  18. A new method of detection for a positron emission tomograph using a time of flight method

    International Nuclear Information System (INIS)

    Gresset, Christian.

    1981-05-01

    In the first chapter, it is shown the advantages of positron radioemitters (β + ) of low period, and the essential characteristics of positron tomographs realized at the present time. The second chapter presents the interest of an original technique of image reconstruction: the time of flight technique. The third chapter describes the characterization methods which were set for verifying the feasibility of cesium fluoride in tomography. Chapter four presents the results obtained by these methods. It appears that the cesium fluoride constitute presently the best positron emission associated to time of flight technique. The hypotheses made on eventual performances of such machines are validated by experiments with phantom. The results obtained with a detector (bismuth germanate) conserves all its interest in skull tomography [fr

  19. Emission tomography with positrons principle, physical performances of a ring detector and quantitative possibilities

    International Nuclear Information System (INIS)

    Soussaline, F.; Plummer, D.; Todd Pokropek, A.E.; Loc'h, C.; Comar, D.

    1979-01-01

    Satisfactory qualitative and quantitative data in positron emission tomography requires the use of a well adapted tomographic system. A number of parameters have been identified which can be considered as the critical characteristics for evaluation and intercomparison of such systems. Using these the choice of a single slice ring positron camera could be justified by its physical performance, which is presented and discussed. Series of physical and mathematical simulations allow an appropriate knowledge of such a system, which has been in use for more than a year in a clinical environment. These studies aid to the interpretation of very interesting physiopathologic studies. In principle, a positron tomographic system permits measurement of absolute quantitative concentration values, which are essential for precise metabolic studies. The main sources of error comprising the calibration of the system, the tail effects and the precision for attenuation correction are analysed. When taking in account these errors, a precision of the order of 10% should be obtainable [fr

  20. Fluorodeoxyglucose positron emission tomography scan may be helpful in the case of ductal variant prostate cancer when prostate specific membrane antigen ligand positron emission tomography scan is negative

    International Nuclear Information System (INIS)

    McEwan, Louise M.; Wong, David; Yaxley, John

    2017-01-01

    Gallium-68 prostate specific membrane antigen ligand (Ga-68 PSMA) positron emission tomography/computed tomography (PET/CT) scanning is emerging as a useful imaging modality for the staging of suspected and known recurrent or metastatic prostate cancer and in staging of newly diagnosed higher grade prostate cancer. However, we have observed at our institution that in some cases of the more aggressive ductal variant, Ga-68 PSMA uptake has sometimes been poor compared with prominent 18-fluorodeoxyglucose (F-18 FDG) avidity seen in F-18 FDG PET/CT, which would suggest that FDG PET/CT scans are important in staging of ductal pattern prostate cancer.

  1. Positron emission tomography studies of central receptors in humans

    International Nuclear Information System (INIS)

    Baron, J.C.; Maziere, B.

    1986-01-01

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

  2. 18F-fluorodeoxyglucose positron emission tomography in colorectal cancer: value in primary staging and follow-up

    International Nuclear Information System (INIS)

    Joerg, L.; Heinisch, M.; Rechberger, E.; Kurz, F.; Klug, R.; Aufschnaiter, M; Hammer, J.; Langsteger, W.

    2002-01-01

    Positron emission tomography using 18 F-fluorodeoxyglucose (FDG-PET) is a encouraging imaging techniques allowing a highly sensitive whole-body search for malignant foci detected by their increased glucose metabolism compared with benign tissues. Several studies are now available that indicate its added value for diagnosis and staging of colorectal cancer. In all, patient management seems to be changed in 20-30 % of patients who undergo fluorodeoxyglucose positron emission tomography in addition to standard staging procedures. Fluorodeoxyglucose positron emission tomography is also useful in monitoring radiation therapy and chemotherapy. Regarding preoperative staging of primary colorectal cancer the literature is very limited. (author)

  3. Basal ganglia disorders studied by positron emission tomography

    International Nuclear Information System (INIS)

    Shinotoh, Hitoshi

    1994-01-01

    Recent development of positron emitting radioligands has made it possible to investigate the alterations of neurotransmitter systems associated with basal ganglia disorders in vivo. The functional integrity of nigro-striatal dopaminergic terminals may be studied with [ 18 F]6-fluoro-L-dopa ([ 18 F]dopa), and striatal dopamine receptor density with suitable PET ligands. [ 18 F]dopa uptake in the striatum (putamen) is markedly reduced in patients with Parkinson's disease (PD). [ 18 F]dopa-PET is capable of detecting sub-clinical nigral dysfunction in asymptomatic patients with familial PD and those who become Parkinsonian on conventional doses of dopamine receptor antagonists. While putamen [ 18 F]dopa uptake is reduced to a similar level in patients with multiple system atrophy (MSA) and PD, caudate [ 18 F] dopa uptake is lower in MSA than PD. However, [ 18 F]dopa PET cannot consistently distinguish MSA from PD because individual ranges of caudate [ 18 F]dopa uptake overlap. D 1 and D 2 receptor binding is markedly reduced in the striatum (posterior putamen) of MSA patients. Therefore, dopamine receptor imaging is useful for the differential diagnosis of MSA and PD. Similar marked reductions in putamen and caudate [ 18 F]dopa uptake have been observed in patients with progressive supranuclear palsy (PSP). Moderate reductions in D 2 receptor binding have been reported in the striatum of PSP patients. The reduction in D 2 receptor binding is more prominent in the caudate than putamen. Striatal [ 18 F]dopa uptake is normal or only mildly reduced in patients with dopa responsive dystonia (DRD). D 2 receptor binding is markedly reduced in patients with Huntington's disease, while striatal [ 18 F]dopa uptake is normal or mildly reduced. In summary, PET can demonstrate characteristic patterns of disruption of dopaminergic systems associated with basal ganglia disorders. These PET findings are useful in the differential diagnosis of basal ganglia disorders. (J.P.N.) 55 refs

  4. Effect of ginseng pretreatment on cerebral glucose metabolism in ischaemic rats using animal positron emission tomography (PET) and [18F]-FDG

    Energy Technology Data Exchange (ETDEWEB)

    Rye, Choi Seok; Magata, Y.; Saji, H.; Tajima, K.; Kitano, H.; Konishi, J.; Yokoyama, A. [Department of Radiopharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-01 (Japan)

    1997-07-01

    To investigate the effect of ginseng on damaged brain activity, we evaluated the cerebral metabolic rate of glucose (CMRglc) as a functional index in post-ischaemic rats and compared the results with those obtained after the administration of a ginseng extract. CMRglc was measured using high resolution animal positron emission tomography with {sup 18}F-2-fluoro-2-deoxy-D-glucose ({sup 18}F-FDG). The rats subjected to a 30-min occlusion showed a significant reduction of k3, the rate constant for phosphorylation of {sup 18}F-FDG by hexokinase, compared with the normal value. The ginseng pretreatment prevented the reduction in k3 and CMRglc caused by ischaemia. Although further investigation is needed to elucidate the mechanism of action, ginseng may be useful for prevention and treatment of ischaemia. © 1997 John Wiley & Sons, Ltd.

  5. Regional myocardial blood flow, metabolism and function assessed noninvasively by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-01-01

    Positron emission computed tomography is a new technique for the noninvasive measure of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study means is due to the technological innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that reflect quantitatively regional tracer tissue concentrations. By employing tracer kinetic models this new technique permits the measurement of regional glucose and fatty acid metabolism of the heart. While already an important new tool for investigative studies into cardiac physiology and pathophysiology, the clinical utility of positron emission tomography remains to be defined.

  6. Persistence of cerebral metabolic abnormalities in chronic schizophrenia as determined by positron emission tomography

    International Nuclear Information System (INIS)

    Wolkin, A.; Jaeger, J.; Brodie, J.D.; Wolf, A.P.; Fowler, J.; Rotrosen, J.; Gomez-Mont, F.; Cancro, R.

    1985-01-01

    Local cerebral metabolic rates were determined by positron emission tomography and the deoxyglucose method in a group of 10 chronic schizophrenic subjects before and after somatic treatment and in eight normal subjects. Before treatment, schizophrenic subjects had markedly lower absolute metabolic activity than did normal controls in both frontal and temporal regions and a trend toward relative hyperactivity in the basal ganglia area. After treatment, their metabolic rates approached those seen in normal subjects in nearly all regions except frontal. Persistence of diminished frontal metabolism was manifested as significant relative hypofrontality. These findings suggest specific loci of aberrant cerebral functioning in chronic schizophrenia and the utility of positron emission tomography in characterizing these abnormalities

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

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

    1985-01-01

    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

  9. A positron emission tomography study of cardiac sequelae in children with Kawasaki disease, 1

    International Nuclear Information System (INIS)

    Ohmochi, Yutaka

    1994-01-01

    This study quantitatively measured regional myocardial blood flow (MBF) and perfusable tissue fraction (pTF) in 25 children (mean age: 17.2±2.7) with Kawasaki disease using positron emission tomography and H 2 15 O. Patients were divided into three groups based on coronary angiographic findings. Group 1 consisted of 11 patients with normal coronary angiograms; Group 2, 7 patients with stenotic coronary lesions. There were no significant differences in MBF and pTF among 5 divided regions on the left ventricular wall. Average MBF at rest in Group 1 was 0.91±0.19 ml/min/g. There was a poor correlation between MBF estimated positron emission tomography and patient's age in Group 1. (r=-0.374, Y=-0.0234X + 1.254: p 2 15 O, to determine the functional capacity of coronary artery lesions and myocardial damage in children with Kawasaki disease. (author)

  10. Performance evaluation of BGO block detectors used in positron emission tomography and a coincidence system

    International Nuclear Information System (INIS)

    Kim, J. H.; Choi, Y.; Lim, K. C.; Lee, M. Y.; Woo, S. K.; Lee, K. H.; Kim, S. E.; Choi, Y. S.; Kim, B. T.

    1999-01-01

    We investigated the basic performances of the BGO block detectors, which is used in the GE Advance positron emission tomography. The block detector is composed of 36 small BGO crystals coupled to two 2-channel photomultiplier tubes. In this study, we measured the crystal map and the intrinsic energy resolution of the detector. The coincidence signals between the detectors were also obtained using F-18. The intrinsic energy resolution of the block detector was 69% FWHM at 140 keV and 33% FWHM at 511 keV. High quality crystal map and the coincidence signals between the detectors were successfully obtained. The timing resolution of the detectors are being measured. The results of this study demonstrate the feasibility of developing high performance positron emission tomography

  11. Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands.

    Science.gov (United States)

    Taylor, Nicholas J; Emer, Enrico; Preshlock, Sean; Schedler, Michael; Tredwell, Matthew; Verhoog, Stefan; Mercier, Joel; Genicot, Christophe; Gouverneur, Véronique

    2017-06-21

    Molecules labeled with fluorine-18 ( 18 F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18 F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18 F-fluorination of aryl boron reagents with 18 F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18 F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.

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

    CERN Document Server

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

    2001-01-01

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

  13. A feature point identification method for positron emission particle tracking with multiple tracers

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Cody, E-mail: cwiggin2@vols.utk.edu [University of Tennessee-Knoxville, Department of Physics and Astronomy, 1408 Circle Drive, Knoxville, TN 37996 (United States); Santos, Roque [University of Tennessee-Knoxville, Department of Nuclear Engineering (United States); Escuela Politécnica Nacional, Departamento de Ciencias Nucleares (Ecuador); Ruggles, Arthur [University of Tennessee-Knoxville, Department of Nuclear Engineering (United States)

    2017-01-21

    A novel detection algorithm for Positron Emission Particle Tracking (PEPT) with multiple tracers based on optical feature point identification (FPI) methods is presented. This new method, the FPI method, is compared to a previous multiple PEPT method via analyses of experimental and simulated data. The FPI method outperforms the older method in cases of large particle numbers and fine time resolution. Simulated data show the FPI method to be capable of identifying 100 particles at 0.5 mm average spatial error. Detection error is seen to vary with the inverse square root of the number of lines of response (LORs) used for detection and increases as particle separation decreases. - Highlights: • A new approach to positron emission particle tracking is presented. • Using optical feature point identification analogs, multiple particle tracking is achieved. • Method is compared to previous multiple particle method. • Accuracy and applicability of method is explored.

  14. Regional myocardial blood flow, metabolism and function assessed noninvasively by positron emission tomography

    International Nuclear Information System (INIS)

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

    1979-01-01

    Positron emission computed tomography is a new technique for the noninvasive measure of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study means is due to the technological innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that reflect quantitatively regional tracer tissue concentrations. By employing tracer kinetic models this new technique permits the measurement of regional glucose and fatty acid metabolism of the heart. While already an important new tool for investigative studies into cardiac physiology and pathophysiology, the clinical utility of positron emission tomography remains to be defined

  15. Basal ganglia disorders studied by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Shinotoh, Hitoshi [Chiba Univ. (Japan). School of Medicine

    1994-04-01

    Recent development of positron emitting radioligands has made it possible to investigate the alterations of neurotransmitter systems associated with basal ganglia disorders in vivo. The functional integrity of nigro-striatal dopaminergic terminals may be studied with [[sup 18]F]6-fluoro-L-dopa ([[sup 18]F]dopa), and striatal dopamine receptor density with suitable PET ligands. [[sup 18]F]dopa uptake in the striatum (putamen) is markedly reduced in patients with Parkinson's disease (PD). [[sup 18]F]dopa-PET is capable of detecting sub-clinical nigral dysfunction in asymptomatic patients with familial PD and those who become Parkinsonian on conventional doses of dopamine receptor antagonists. While putamen [[sup 18]F]dopa uptake is reduced to a similar level in patients with multiple system atrophy (MSA) and PD, caudate [[sup 18]F] dopa uptake is lower in MSA than PD. However, [[sup 18]F]dopa PET cannot consistently distinguish MSA from PD because individual ranges of caudate [[sup 18]F]dopa uptake overlap. D[sub 1] and D[sub 2] receptor binding is markedly reduced in the striatum (posterior putamen) of MSA patients. Therefore, dopamine receptor imaging is useful for the differential diagnosis of MSA and PD. Similar marked reductions in putamen and caudate [[sup 18]F]dopa uptake have been observed in patients with progressive supranuclear palsy (PSP). Moderate reductions in D[sub 2] receptor binding have been reported in the striatum of PSP patients. The reduction in D[sub 2] receptor binding is more prominent in the caudate than putamen. Striatal [[sup 18]F]dopa uptake is normal or only mildly reduced in patients with dopa responsive dystonia (DRD). D[sub 2] receptor binding is markedly reduced in patients with Huntington's disease, while striatal [[sup 18]F]dopa uptake is normal or mildly reduced. In summary, PET can demonstrate characteristic patterns of disruption of dopaminergic systems associated with basal ganglia disorders. (J.P.N.) 55 refs.

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

    DEFF Research Database (Denmark)

    Schlünzen, L; Juul, N; Hansen, K V

    2010-01-01

    BACKGROUND: 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. METHODS: Eight...... areas by 48-71% of the baseline (Pbrain 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....

  17. Dynamic positron emission tomography in man using small bismuth germanate crystals

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Budinger, T.F.; Huesman, R.H.; Cahoon, J.L.

    1982-04-01

    Primary considerations for the design of positron emission tomographs for medical studies in humans are the need for high imaging sensitivity, whole organ coverage, good spatial resolution, high maximum data rates, adequate spatial sampling with minimum mechanical motion, shielding against out of plane activity, pulse height discrimination against scattered photons, and timing discrimination against accidental coincidences. We discuss the choice of detectors, sampling motion, shielding, and electronics to meet these objectives

  18. 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography in Tuberculosis: Spectrum of Manifestations.

    Science.gov (United States)

    Agarwal, Krishan Kant; Behera, Abhishek; Kumar, Rakesh; Bal, Chandrasekhar

    2017-01-01

    The objective of this article is to provide an illustrative tutorial highlighting the utility of 18 F-fluorodeoxyglucose-positron emission tomography/computed tomography ( 18 F-FDG-PET/CT) imaging to detect spectrum of manifestations in patients with tuberculosis (TB). FDG-PET/CT is a powerful tool for early diagnosis, measuring the extent of disease (staging), and consequently for evaluation of response to therapy in patients with TB.

  19. Positron-emission tomography as a new direction in radiation medicine development (scientometric analysis)

    International Nuclear Information System (INIS)

    Artamonova, N.O.; Masyich, O.V.; Pavlyichenko, Yu.V.; Shepeljev, A.G.; Kuryilo, Yu.P.; Ponomarenko, T.O.

    2009-01-01

    The contemporary state and prospects of positron-emission tomography (PET) application in diagnosis of cancer diseases are investigated. The comparative analysis of the image of the topical field in Medline and INIS allowed to allocate the zones of intensive investigation of PET efficacy at cancer diseases, investigations of the brain, lungs, heart as well as to establish the peculiarities of the search depending on the features of their search interfaces

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    OBJECTIVES: Atherosclerosis is recognised as an inflammatory disease, and new diagnostic tools are warranted to evaluate plaque inflammatory activity and risk of cardiovascular events. We investigated [18]-fluorodeoxyglucose (FDG) uptake in vulnerable carotid plaques visualised by positron emission...... tomography (PET). Uptake was correlated to quantitative gene expression of known markers of inflammation and plaque vulnerability. METHODS: Ten patients with recent transient ischaemic attack and carotid artery stenosis (>50%) underwent combined FDG-PET and computed tomography angiography (CTA) the day...

  1. A tumor-targeted polymer theranostics platform for positron emission tomography and fluorescence imaging

    Czech Academy of Sciences Publication Activity Database

    Koziolová, Eva; Goel, S.; Chytil, Petr; Janoušková, Olga; Barnhart, T. E.; Cai, W.; Etrych, Tomáš

    2017-01-01

    Roč. 9, č. 30 (2017), s. 10906-10918 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-02986S; GA MZd(CZ) NV16-28594A; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers * positron emission tomography ( PET ) * fluorescence imaging Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.367, year: 2016

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

    International Nuclear Information System (INIS)

    Litton, J.E.; Eriksson, L.

    1990-01-01

    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

  3. Positron Emission Tomography in Prostate Cancer: Summary of Systematic Reviews and Meta-Analysis

    OpenAIRE

    Jadvar, Hossein

    2015-01-01

    Prostate cancer is a prevalent public health problem worldwide. Over the past decade, there has been tremendous research activity in the potential use of positron emission tomography with a number of radiotracers targeted to various biological aspects of this complex tumor. Systematic reviews and meta-analysis are important contributions to the relevant literature that summarize the evidence while reducing the effect of various sources of bias in the published data. The accumulation of releva...

  4. A promising new mechanism of ionizing radiation detection for positron emission tomography: Modulation of optical properties

    OpenAIRE

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

    2016-01-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we...

  5. A statistical analysis of count normalization methods used in positron-emission tomography

    International Nuclear Information System (INIS)

    Holmes, T.J.; Ficke, D.C.; Snyder, D.L.

    1984-01-01

    As part of the Positron-Emission Tomography (PET) reconstruction process, annihilation counts are normalized for photon absorption, detector efficiency and detector-pair duty-cycle. Several normalization methods of time-of-flight and conventional systems are analyzed mathematically for count bias and variance. The results of the study have some implications on hardware and software complexity and on image noise and distortion

  6. Positron-emission tomography imaging of long-term shape recognition challenges

    OpenAIRE

    Rosier, A.; Cornette, L.; Dupont, P.; Bormans, G.; Michiels, J.; Mortelmans, L.; Orban, G. A.

    1997-01-01

    Long-term visual memory performance was impaired by two types of challenges: a diazepam challenge on acquisition and a sensory challenge on recognition. Using positron-emission tomography regional cerebral blood flow imaging, we studied the effect of these challenges on regional brain activation during the delayed recognition of abstract visual shapes as compared with a baseline fixation task. Both challenges induced a significant decrease in differential activation in the left fusiform gyrus...

  7. Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography

    International Nuclear Information System (INIS)

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

    While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography ( 13 N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique

  8. Dynamic Positron Emission Tomography [PET] in Man Using Small Bismuth Germanate Crystals

    Science.gov (United States)

    Derenzo, S. E.; Budinger, T. F.; Huesman, R. H.; Cahoon, J. L.

    1982-04-01

    Primary considerations for the design of positron emission tomographs for medical studies in humans are the need for high imaging sensitivity, whole organ coverage, good spatial resolution, high maximum data rates, adequate spatial sampling with minimum mechanical motion, shielding against out of plane activity, pulse height discrimination against scattered photons, and timing discrimination against accidental coincidences. We discuss the choice of detectors, sampling motion, shielding, and electronics to meet these objectives.

  9. A multicrystal two dimensional BGO detector system for positron emission tomography

    International Nuclear Information System (INIS)

    Casey, M.E.; Nutt, R.

    1986-01-01

    This paper presents a discussion of a new multicrystal detector system as it is implemented in Positron Emission Tomography. The system consists of a 32 x 8 matrix of BGO crystals, a tuned light pipe, and four photomultipliers. The electronics that decodes the position consists of fast preamps, gated integrators, and level comparators. This detector represents a major development toward reducing the cost of PET

  10. Alternative positron emission tomography with non-conventional positron emitters: effects of their physical properties on image quality and potential clinical applications

    International Nuclear Information System (INIS)

    Pagani, M.; Stone-Elander, S.; Larsson, S.A.

    1997-01-01

    The increasing amount of clinically relevant information obtained by positron emission tomography (PET), primarily with fluorine-18 labelled 2-deoxy-2-fluoro-d-glucose, has generated a demand for new routes for the widespread and cost-efficient use of positron-emitting radiopharmaceuticals. New dual-head single-photon emission tomography (SPET) cameras are being developed which offer coincidence detection with camera heads lacking a collimator or SPET imaging with specially designed collimators and additional photon shielding. Thus, not only satellite PET imaging units but also nuclear medicine units investing in these new SPET/PET systems need to examine all available alternatives for rational radionuclide supplies from host cyclotrons. This article examines 25 ''alternative'' positron-emitting radionuclides, discusses the impact of their decay properties on image quality and reviews methods for their production as well as for their application in imaging techniques. (orig.)

  11. Positron Emission Tomography in Prostate Cancer: Summary of Systematic Reviews and Meta-Analysis.

    Science.gov (United States)

    Jadvar, Hossein

    2015-09-01

    Prostate cancer is a prevalent public health problem worldwide. Over the past decade, there has been tremendous research activity in the potential use of positron emission tomography with a number of radiotracers targeted to various biological aspects of this complex tumor. Systematic reviews and meta-analysis are important contributions to the relevant literature that summarize the evidence while reducing the effect of various sources of bias in the published data. The accumulation of relevant data in this clinical setting has recently provided the opportunity for systematic reviews. In this brief article, I summarize the published systematic reviews and meta-analysis of positron emission tomography in prostate cancer. Most robust evidence suggests a probable role for first-line use of positron emission tomography with radiolabeled choline in restating patients with biochemical relapse of prostate cancer with the diagnostic performance that appears to be positively associated with the serum prostate specific antigen level and velocity. Future systematic reviews will be needed for other emerging radiotracers such as those based on prostate specific membrane antigen and gastrin-releasing peptide receptor.

  12. 2-¹⁸fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) for postchemotherapy seminoma residual lesions

    DEFF Research Database (Denmark)

    Bachner, M; Loriot, Y; Gross-Goupil, M

    2012-01-01

    2-¹⁸fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) has been recommended in international guidelines in the evaluation of postchemotherapy seminoma residuals. Our trial was designed to validate these recommendations in a larger group of patients.......2-¹⁸fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) has been recommended in international guidelines in the evaluation of postchemotherapy seminoma residuals. Our trial was designed to validate these recommendations in a larger group of patients....

  13. The role of (18)fluoro-deoxyglucose positron emission tomography/computed tomography in resectable pancreatic cancer.

    Science.gov (United States)

    Crippa, Stefano; Salgarello, Matteo; Laiti, Silvia; Partelli, Stefano; Castelli, Paola; Spinelli, Antonello E; Tamburrino, Domenico; Zamboni, Giuseppe; Falconi, Massimo

    2014-08-01

    The role of (18)fluoro-deoxyglucose positron emission tomography/computed tomography in pancreatic ductal adenocarcinoma is debated. We retrospectively assessed the value of (18)fluoro-deoxyglucose positron emission tomography/computed tomography in addition to conventional imaging as a staging modality in pancreatic cancer. (18)Fluoro-deoxyglucose positron emission tomography/computed tomography was performed in 72 patients with resectable pancreatic carcinoma after multi-detector computed tomography positron emission tomography was considered positive for a maximum standardized uptake value >3. Overall, 21% of patients had a maximum standardized uptake value ≤ 3, and 60% of those had undergone neoadjuvant treatment (P=0.0001). Furthermore, 11% of patients were spared unwarranted surgery since positron emission tomography/computed tomography detected metastatic disease. All liver metastases were subsequently identified with contrast-enhanced ultrasound. Sensitivity and specificity of positron emission tomography/computed tomography for distant metastases were 78% and 100%. The median CA19.9 concentration was 48.8 U/mL for the entire cohort and 292 U/mL for metastatic patients (P=0.112). The widespread application of (18)fluoro-deoxyglucose positron emission tomography/computed tomography in patients with resectable pancreatic carcinoma seems not justified. It should be considered in selected patients at higher risk of metastatic disease (i.e. CA19.9>200 U/mL) after undergoing other imaging tests. Neoadjuvant treatment is significantly associated with low metabolic activity, limiting the value of positron emission tomography in this setting. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  14. Combined use of positron emission tomography and volume doubling time in lung cancer screening with low-dose CT scanning

    DEFF Research Database (Denmark)

    Ashraf, H; Dirksen, A; Jakobsen, Annika Loft

    2011-01-01

    In lung cancer screening the ability to distinguish malignant from benign nodules is a key issue. This study evaluates the ability of positron emission tomography (PET) and volume doubling time (VDT) to discriminate between benign and malignant nodules.......In lung cancer screening the ability to distinguish malignant from benign nodules is a key issue. This study evaluates the ability of positron emission tomography (PET) and volume doubling time (VDT) to discriminate between benign and malignant nodules....

  15. High resolution ultrasonic densitometer

    International Nuclear Information System (INIS)

    Dress, W.B.

    1983-01-01

    The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks

  16. Tomography by positrons emission: integral unit to the service of Mexico; Tomografia por emision de positrones: unidad integral al servicio de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez D, F A [Unidad PET-Ciclotron, Facultad de Medicina, UNAM (Mexico)

    2005-07-01

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

  17. Time-of-flight positron emission tomography using optical fiber circuit

    International Nuclear Information System (INIS)

    Yamawaki, Masato; Katsumura, Yousuke; Suzuki, Takenori

    2008-01-01

    The measurement method and system architecture of a new time-of-flight positron emission tomography (TOF-PET) system are proposed. This system collects scintillation light using optical fibers connected directly to scintillators and measures the position of positron annihilation. Many scintillators are placed cylindrically whereby a pair of scintillators detects a pair of γ-rays generated at the positron annihilation point. Optical fiber circuits, most of which are bundles of optical fibers bound clockwise or counterclockwise around the cylinder of scintillators, collect light signals generated by γ-rays. These light signals are amplified by several photomultiplier tubes and processed using a single digital oscilloscope to determine the TOF of the positron annihilation γ-rays. One of the most important factors in the performance of the TOF-PET system is the TOF resolution. When fiber circuits are used for transmitting light signals, the dispersion of light signals and the decrease in light intensity are the major factors in the deterioration of the TOF resolution. The result of the preliminary experiment leads to the conclusion that the use of optical fibers degrades the intensity of light but does not severely degrade the TOF resolution. (author)

  18. X-ray-based attenuation correction for positron emission tomography/computed tomography scanners.

    Science.gov (United States)

    Kinahan, Paul E; Hasegawa, Bruce H; Beyer, Thomas

    2003-07-01

    A synergy of positron emission tomography (PET)/computed tomography (CT) scanners is the use of the CT data for x-ray-based attenuation correction of the PET emission data. Current methods of measuring transmission use positron sources, gamma-ray sources, or x-ray sources. Each of the types of transmission scans involves different trade-offs of noise versus bias, with positron transmission scans having the highest noise but lowest bias, whereas x-ray scans have negligible noise but the potential for increased quantitative errors. The use of x-ray-based attenuation correction, however, has other advantages, including a lack of bias introduced from post-injection transmission scanning, which is an important practical consideration for clinical scanners, as well as reduced scan times. The sensitivity of x-ray-based attenuation correction to artifacts and quantitative errors depends on the method of translating the CT image from the effective x-ray energy of approximately 70 keV to attenuation coefficients at the PET energy of 511 keV. These translation methods are usually based on segmentation and/or scaling techniques. Errors in the PET emission image arise from positional mismatches caused by patient motion or respiration differences between the PET and CT scans; incorrect calculation of attenuation coefficients for CT contrast agents or metallic implants; or keeping the patient's arms in the field of view, which leads to truncation and/or beam-hardening (or x-ray scatter) artifacts. Proper interpretation of PET emission images corrected for attenuation by using the CT image relies on an understanding of the potential artifacts. In cases where an artifact or bias is suspected, careful inspection of all three available images (CT and PET emission with and without attenuation correction) is recommended. Copyright 2003 Elsevier Inc. All rights reserved.

  19. Software development for modeling positrons emission tomograph scanners; Desenvolvimento de um software para modelagem de tomografos por emissao de positrons

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Igor Fagner

    2013-08-01

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

  20. Geneva University - The AX-PET experiment : A demonstrator for an axial Positron Emission Tomography

    CERN Multimedia

    Université de Genève

    2012-01-01

    Geneva University École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92   Wednesday 14 March 2012 SEMINAIRE DE PHYSIQUE CORPUSCULAIRE 11.15 a.m. - Science II, Auditoire 1S081, 30, quai Ernest-Ansermet, 1211 Genève 4 The AX-PET experiment : A demonstrator for an axial Positron Emission Tomography Dr Chiara CASELLA   ETH Zurich   PET (Positron Emission Tomography) is a tool for in-vivo functional imaging, successfully used since the earliest days of nuclear medicine. It is based on the detection of the two coincident 511 keV photons from the annihilation of a positron, emitted from a radiotracer injected into the body. Tomographic analysis of the coincidence data allows for a 3D reconstructed image of the source distribution. The AX-PET experiment proposes a novel geometrical approach for a PET scanner, in which l...

  1. Carbon-11 and Fluorine-18 Labeled Amino Acid Tracers for Positron Emission Tomography Imaging of Tumors

    Science.gov (United States)

    Sun, Aixia; Liu, Xiang; Tang, Ganghua

    2017-12-01

    Tumor cells have an increased nutritional demand for amino acids(AAs) to satisfy their rapid proliferation. Positron-emitting nuclide labeled AAs are interesting probes and are of great importance for imaging tumors using positron emission tomography (PET). Carbon-11 and fluorine-18 labeled AAs include the [1-11C] amino acids, labeling alpha-C- amino acids, the branched-chain of amino acids and N-substituted carbon-11 labeled amino acids. These tracers target protein synthesis or amino acid(AA) transport, and their uptake mechanism mainly involves AA transport. AA PET tracers have been widely used in clinical settings to image brain tumors, neuroendocrine tumors, prostate cancer, breast cancer, non–small cell lung cancer (NSCLC) and hepatocellular carcinoma. This review focuses on the fundamental concepts and the uptake mechanism of AAs, AA PET tracers and their clinical applications.

  2. Enhancement of molecular sensitivity in positron emission tomography with quantum correlation of γ-ray photons

    Science.gov (United States)

    Sato, K.; Kobayashi, Y.

    2015-05-01

    Enhancement of molecular sensitivity in positron emission tomography (PET) has long been discussed with respect to imaging instrumentation and algorithms for data treatment. Here, the molecular sensitivity in PET is discussed on the basis of 2-dimensional coincident measurements of 511 keV γ ray photons resultant from two-photon annihilation. Introduction of an additional selection window based on the energy sum and difference of the coincidently measured γ ray photons, without any significant instrumental and algorithmic changes, showed an improvement in the signal-to-noise ratio (SNR) by an order of magnitude. Improvement of performance characteristics in the PET imaging system was demonstrated by an increase in the noise equivalent count rate (NECR) which takes both the SNR and the detection efficiency into consideration. A further improvement of both the SNR and the NECR is expected for the present system in real clinical and in-vivo environments, where much stronger positron sources are employed.

  3. Enhancement of molecular sensitivity in positron emission tomography with quantum correlation of γ-ray photons

    International Nuclear Information System (INIS)

    Sato, K.; Kobayashi, Y.

    2015-01-01

    Enhancement of molecular sensitivity in positron emission tomography (PET) has long been discussed with respect to imaging instrumentation and algorithms for data treatment. Here, the molecular sensitivity in PET is discussed on the basis of 2-dimensional coincident measurements of 511 keV γ ray photons resultant from two-photon annihilation. Introduction of an additional selection window based on the energy sum and difference of the coincidently measured γ ray photons, without any significant instrumental and algorithmic changes, showed an improvement in the signal-to-noise ratio (SNR) by an order of magnitude. Improvement of performance characteristics in the PET imaging system was demonstrated by an increase in the noise equivalent count rate (NECR) which takes both the SNR and the detection efficiency into consideration. A further improvement of both the SNR and the NECR is expected for the present system in real clinical and in-vivo environments, where much stronger positron sources are employed

  4. Visualization of muscles involved in unilateral tremor using 13N-ammonia and positron emission tomography

    International Nuclear Information System (INIS)

    Schelstraete, K.; Simons, M.; Deman, J.; Vermeulen, F.L.; Ghent Rijksuniversiteit; Goethals, P.; Bratzlavsky, M.

    1982-01-01

    Using positron emission computerized tomography (PCT), a high uptake of IV injected 13 N-ammonia was observed in the muscles of the right forearm and leg of a patient with a rightsided static tremor. In some mucles the concentration of 13 NH 3 was 8.5 times higher than in the symmetrical normal limb. Confrontation of the clinical, neurological, and electroyographic findings with the results of the PCT proved that the muscles with the high uptake corresponded to the muscles responsible for the tremulous movements. There is strong evidence that the high uptake of 13 NH 3 was related to the increased blood flow produced by the continuous rhythmic exercise of the muscles involved in the tremor. To our knowledge a similar observation has not been described before. It is suggested that the combined use of suitable positron emitters and PCT might provide a valuable tool for the noninvasive study of perfusion of individual skeletal muscles. (orig.)

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

    International Nuclear Information System (INIS)

    Leenders, K.L.; Frackowiak, R.S.; Quinn, N.; Marsden, C.D.

    1986-01-01

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

  6. High resolution tomography using analog coding

    International Nuclear Information System (INIS)

    Brownell, G.L.; Burnham, C.A.; Chesler, D.A.

    1985-01-01

    As part of a 30-year program in the development of positron instrumentation, the authors have developed a high resolution bismuth germanate (BGO) ring tomography (PCR) employing 360 detectors and 90 photomultiplier tubes for one plane. The detectors are shaped as trapezoid and are 4 mm wide at the front end. When assembled, they form an essentially continuous cylindrical detector. Light from a scintillation in the detector is viewed through a cylindrical light pipe by the photomultiplier tubes. By use of an analog coding scheme, the detector emitting light is identified from the phototube signals. In effect, each phototube can identify four crystals. PCR is designed as a static device and does not use interpolative motion. This results in considerable advantage when performing dynamic studies. PCR is the positron tomography analog of the γ-camera widely used in nuclear medicine

  7. A Movable Phantom Design for Quantitative Evaluation of Motion Correction Studies on High Resolution PET Scanners

    DEFF Research Database (Denmark)

    Olesen, Oline Vinter; Svarer, C.; Sibomana, M.

    2010-01-01

    maximization algorithm with modeling of the point spread function (3DOSEM-PSF), and they were corrected for motions based on external tracking information using the Polaris Vicra real-time stereo motion-tracking system. The new automatic, movable phantom has a robust design and is a potential quality......Head movements during brain imaging using high resolution positron emission tomography (PET) impair the image quality which, along with the improvement of the spatial resolution of PET scanners, in general, raises the importance of motion correction. Here, we present a new design for an automatic...

  8. The simulation of a data acquisition system for a proposed high resolution PET scanner

    Energy Technology Data Exchange (ETDEWEB)

    Rotolo, C.; Larwill, M.; Chappa, S. [Fermi National Accelerator Lab., Batavia, IL (United States); Ordonez, C. [Chicago Univ., IL (United States)

    1993-10-01

    The simulation of a specific data acquisition (DAQ) system architecture for a proposed high resolution Positron Emission Tomography (PET) scanner is discussed. Stochastic processes are used extensively to model PET scanner signal timing and probable DAQ circuit limitations. Certain architectural parameters, along with stochastic parameters, are varied to quantatively study the resulting output under various conditions. The inclusion of the DAQ in the model represents a novel method of more complete simulations of tomograph designs, and could prove to be of pivotal importance in the optimization of such designs.

  9. The simulation of a data acquisition system for a proposed high resolution PET scanner

    International Nuclear Information System (INIS)

    Rotolo, C.; Larwill, M.; Chappa, S.; Ordonez, C.

    1993-10-01

    The simulation of a specific data acquisition (DAQ) system architecture for a proposed high resolution Positron Emission Tomography (PET) scanner is discussed. Stochastic processes are used extensively to model PET scanner signal timing and probable DAQ circuit limitations. Certain architectural parameters, along with stochastic parameters, are varied to quantatively study the resulting output under various conditions. The inclusion of the DAQ in the model represents a novel method of more complete simulations of tomograph designs, and could prove to be of pivotal importance in the optimization of such designs

  10. An inventory of the emission of ammonia from agricultural fertilizer application in China for 2010 and its high-resolution spatial distribution

    NARCIS (Netherlands)

    Xu, Peng; Zhang, Yisheng; Gong, Weiwei; Hou, Xikang; Kroeze, Carolien; Gao, Wei; Luan, Shengji

    2015-01-01

    In an agricultural county like China, agricultural fertilizers are the source of ammonia (NH3) emissions. However, the spatial variability in NH3 emissions is large, and the associated uncertainties affect the reliability of total NH3 emission estimates. In this

  11. {sup 18}F-fluorodeoxyglucose positron emission tomography-computed tomography in the management of adult multisystem Langerhans cell histiocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Obert, Julie [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Centre National de Reference de l' Histiocytose Langerhansienne, Service de Pneumologie, Hopital Saint-Louis, Paris (France); Vercellino, Laetitia [Assistance Publique-Hopitaux de Paris, Service de Medecine Nucleaire, Hopital Saint-Louis, Paris (France); Van der Gucht, Axel [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Service de Medecine Nucleaire, Hopital Saint-Louis, Paris (France); De Margerie-Mellon, Constance [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Service de Radiologie, Hopital Saint-Louis, Paris (France); Bugnet, Emmanuelle; Lorillon, Gwenael [Assistance Publique-Hopitaux de Paris, Centre National de Reference de l' Histiocytose Langerhansienne, Service de Pneumologie, Hopital Saint-Louis, Paris (France); Chevret, Sylvie [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Service de Biostatistique et Information Medicale, Hopital Saint-Louis, Paris (France); Biostatistics and Clinical Epidemiology Research Team, U1153 CRESS, Paris (France); Tazi, Abdellatif [Universite Paris Diderot, Paris (France); Assistance Publique-Hopitaux de Paris, Centre National de Reference de l' Histiocytose Langerhansienne, Service de Pneumologie, Hopital Saint-Louis, Paris (France); Biostatistics and Clinical Epidemiology Research Team, U1153 CRESS, Paris (France)

    2017-04-15

    The standard evaluation of multisystem Langerhans cell histiocytosis (LCH) includes a clinical evaluation, laboratory tests and a skeleton/skull X-ray survey, with chest high-resolution computed tomography (HRCT) in the case of pulmonary involvement. Preliminary reports suggest that {sup 18}F-fluorodeoxyglucose positron emission tomography-computed tomography ({sup 18}F-FDG PET-CT) may be useful for evaluating patients with LCH. Fourteen consecutive adult patients with multisystem LCH were included in this retrospective study, and were evaluated using standard procedures and {sup 18}F-FDG PET-CT. The two sets of findings were compared both at baseline and during follow-up. Serial HRCT and pulmonary function tests were used to evaluate outcome in patients with lung involvement. At the baseline evaluation, PET-CT identified every LCH localization found with the standard evaluation (except a mild cecum infiltration). PET-CT showed additional lesions in seven patients, mostly involving bones, and differentiated inactive from active lesions. Thyroid {sup 18}F-FDG uptake was identified in three cases. No pituitary stalk {sup 18}F-FDG uptake was observed in patients with pituitary LCH. Only 3/12 (25 %) patients with pulmonary LCH displayed moderate pulmonary {sup 18}F-FDG uptake. During follow-up, variations (≥50 % of maximum standardized uptake) in bone {sup 18}F-FDG uptake intensity were correlated with disease state and response to treatment. The absence of lung {sup 18}F-FDG uptake did not preclude lung function improvement after treatment. Except for cases with pulmonary and pituitary involvement, {sup 18}F-FDG PET-CT could replace the standard evaluation for staging of adult patients with multisystem LCH. Serial PET-CT scans are useful for evaluating treatment responses, particularly in cases with bone LCH involvement. (orig.)

  12. Design of an advanced positron emission tomography detector system and algorithms for imaging small animal models of human disease

    Science.gov (United States)

    Foudray, Angela Marie Klohs

    Detecting, quantifying and visualizing biochemical mechanism in a living system without perturbing function is the goal of the instrument and algorithms designed in this thesis. Biochemical mechanisms of cells have long been known to be dependent on the signals they receive from their environment. Studying biological processes of cells in-vitro can vastly distort their function, since you are removing them from their natural chemical signaling environment. Mice have become the biological system of choice for various areas of biomedical research due to their genetic and physiological similarities with humans, the relatively low cost of their care, and their quick breeding cycle. Drug development and efficacy assessment along with disease detection, management, and mechanism research all have benefited from the use of small animal models of human disease. A high resolution, high sensitivity, three-dimensional (3D) positioning positron emission tomography (PET) detector system was designed through device characterization and Monte Carlo simulation. Position-sensitive avalanche photodiodes (PSAPDs) were characterized in various packaging configurations; coupled to various configurations of lutetium oxyorthosilicate (LSO) scintillation crystals. Forty novelly packaged final design devices were constructed and characterized, each providing characteristics superior to commercially available scintillation detectors used in small animal imaging systems: ˜1mm crystal identification, 14-15% of 511 keV energy resolution, and averaging 1.9 to 5.6 ns coincidence time resolution. A closed-cornered box-shaped detector configuration was found to provide optimal photon sensitivity (˜10.5% in the central plane) using dual LSO-PSAPD scintillation detector modules and Monte Carlo simulation. Standard figures of merit were used to determine optimal system acquisition parameters. A realistic model for constituent devices was developed for understanding the signals reported by the

  13. Noninvasive assessment of canine myocardial oxidative metabolism with carbon-11 acetate and positron emission tomography

    International Nuclear Information System (INIS)

    Brown, M.A.; Myears, D.W.; Bergmann, S.R.

    1988-01-01

    Noninvasive quantification of regional myocardial metabolism would be highly desirable to evaluate pathogenetic mechanisms of heart disease and their response to therapy. It was previously demonstrated that the metabolism of radiolabeled acetate, a readily utilized myocardial substrate predominantly metabolized to carbon dioxide (CO2) by way of the tricarboxylic acid cycle, provides a good index of oxidative metabolism in isolated perfused rabbit hearts because of tight coupling between the tricarboxylic acid cycle and oxidative phosphorylation. In the present study, in a prelude to human studies, the relation between myocardial clearance of carbon-11 (11C)-labeled acetate and myocardial oxygen consumption was characterized in eight intact dogs using positron emission tomography. Anesthetized dogs were studied during baseline conditions and again during either high or low work states induced pharmacologically. High myocardial extraction and rapid blood clearance of tracer yielded myocardial images of excellent quality. The turnover (clearance) of 11C radioactivity from the myocardium was biexponential with the mean half-time of the dominant rapid phase averaging 5.4 +/- 2.2, 2.8 +/- 1.3 and 11.1 +/- 1.3 min in control, high and low work load studies, respectively. No significant difference was found between the rate of clearance of 11C radioactivity from the myocardium measured noninvasively with positron emission tomography and the myocardial efflux of 11CO2 measured directly from the coronary sinus. The rate of clearance of the 11C radioactivity from the heart correlated closely with myocardial oxygen consumption (r = 0.90, p less than 0.001) as well as with the rate-pressure product (r = 0.95, p less than 0.001). Hence, the rate of oxidation of 11C-acetate can be determined noninvasively with positron emission tomography, providing a quantitative index of oxidative metabolism under diverse conditions

  14. FEASIBILITY OF POSITRON EMISSION TOMOGRAPHY OF DOSE DISTRIBUTION IN PROTON BEAM CANCER THERAPY

    International Nuclear Information System (INIS)

    BEEBE-WANG, J.J.; DILMANIAN, F.A.; PEGGS, S.G.; SCHLYEER, D.J.; VASKA, P.

    2002-01-01

    Proton therapy is a treatment modality of increasing utility in clinical radiation oncology mostly because its dose distribution conforms more tightly to the target volume than x-ray radiation therapy. One important feature of proton therapy is that it produces a small amount of positron-emitting isotopes along the beam-path through the non-elastic nuclear interaction of protons with target nuclei such as 12 C, 14 N, and 16 O. These radioisotopes, mainly 11 C, 13 N and 15 O, allow imaging the therapy dose distribution using positron emission tomography (PET). The resulting PET images provide a powerful tool for quality assurance of the treatment, especially when treating inhomogeneous organs such as the lungs or the head-and-neck, where the calculation of the dose distribution for treatment planning is more difficult. This paper uses Monte Carlo simulations to predict the yield of positron emitters produced by a 250 MeV proton beam, and to simulate the productions of the image in a clinical PET scanner

  15. Basic concepts on positron emission tomography in oncology and pediatric peculiarities

    International Nuclear Information System (INIS)

    Giammarile, F.; Pellet, O.

    2002-01-01

    (Positron Emission Tomography (PET) is an old functional imaging method, pertaining to the nuclear medicine field, based on the utilisation of positrons emitting nuclei, fixed on targeted molecules. Available since the Seventies, the clinical impact of PET grows daily, particularly in oncology. This method rests on the coincidence detection of the photons issued by the annihilation of the positron. It can be carried out on dedicated scans, equipped with a crown of detectors (PET camera) or on classical cameras whose crystal and electronic system has been adapted CDET camera). The 2-deoxy-2 fluoro-D-glucose marked with fluorine 18 [18FDG or FDG is a glucose analogue. Its cellular uptake uses the facilitated transport of glucose but its metabolism is partial because, contrary to this one, it remains within the cell. This allows functional studies (evaluation of glucose metabolism) on the cell. FDG uptake is thus increased under the pathological conditions comprising an increase in the consumption of glucose either by increase in glycolysis (malignant tumoral tissue) or by increase in the only anaerobic cycle (ischaemia). Consequently, this diagnostic method identifies in vivo the hyper-metabolism of malignant cells and provides a quantification of the tumoral glycolysis, during and after treatment. In Paediatrics, its diffusion and its use in clinical routine, are currently limited, because of the limited availability of the equipment. It is probable that with the awaited rise of PET in France, the paediatric applications will also see their place increasing in the diagnostic strategy of cancer. (authors)

  16. Hard photon emission from high energy electrons and positrons in single crystals

    International Nuclear Information System (INIS)

    Bajer, V.N.; Katkov, V.M.; Strakhovenko, V.M.

    1991-01-01

    A radiation of electrons and positrons in single crystals in coherent bremsstrahlung (CBS) region has been considered for the case when CBS has the most hard spectrum. Under this condition a particle moves near a crystalline plane (in fcc(d) crystal for axis (001) this is the plane (110)) and influence of the continuous plane potential should be taken into account. This potential gives additional contribution in soft part of the spectrum and affects on hard photon emission. Observation of this phenomena at high energy is discussed. 14 refs.; 5 figs.; 1 tab

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

    International Nuclear Information System (INIS)

    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 a CO 2 and increased systolic blood pressure significantly; the change in p a CO 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

  18. Human hemispheric infarction studied by positron emission tomography and the 150 continuous inhalation technique

    International Nuclear Information System (INIS)

    Baron, J.-C.; Bousser, M.G.; Comar, D.; Kellershohn, C.

    1979-01-01

    Positron emission tomography (PET) offers an entirely new approach to the study of the pathophysiology of cerebral ischemic disorders. This is so because for the first time it is possible to obtain functional tomographic images that represent cerebral perfusion and metabolism in a regional basis. We report here a study of cerebral blood flow and oxygen extraction by means of the 15 O inhalation technique in a large number of human hemispheric infarctions. PET imaging with this non-invasive technique has permitted the description of hitherto unreported focal patterns of changes in the CBF/EO2 couple that may have important pathophysiologic and prognostic implications

  19. The potential application of silver and positron emission tomography for in vivo dosimetry during radiotherapy

    DEFF Research Database (Denmark)

    Hansen, Anders T; Hansen, Søren B; Petersen, Jørgen B

    2007-01-01

    of absorbed dose per gram of silver. This demonstrates that it is possible to derive absorbed doses from the radioactivity induced in silver by radiation when measured with the PET scanner. Even though the physical basis for this method is found to be sound, its application, for instance to perform quality......The possible use of silver as a material for in vivo dosimetry in radiotherapy was investigated. The investigation was carried out using a positron emission tomography (PET) scanner, two clinical accelerators and a phantom with silver implants. The phantom was irradiated several times to doses...

  20. Metabolic and hemodynamic evaluation of brain metastases from small cell lung cancer with positron emission tomography

    DEFF Research Database (Denmark)

    Lassen, U; Andersen, P; Daugaard, G

    1998-01-01

    for studies of metabolic and hemodynamic features. This study was performed to determine regional cerebral metabolic rate of glucose (rCMRglu), regional cerebral blood flow (rCBF), and regional cerebral blood volume (rCBV) in brain metastases from small cell lung cancer and the surrounding brain. Tumor r......Brain metastases from small cell lung cancer respond to chemotherapy, but response duration is short and the intracerebral concentration of chemotherapy may be too low because of the characteristics of the blood-brain barrier. Positron emission tomography has been applied in a variety of tumors...