WorldWideScience

Sample records for animal pet imaging

  1. Technology challenges in small animal PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lecomte, Roger E-mail: roger.lecomte@usherbrooke.ca

    2004-07-11

    Positron Emission Tomography (PET) is a non-invasive nuclear imaging modality allowing biochemical processes to be investigated in vivo with sensitivity in the picomolar range. For this reason, PET has the potential to play a major role in the emerging field of molecular imaging by enabling the study of molecular pathways and genetic processes in living animals non-invasively. The challenge is to obtain a spatial resolution that is appropriate for rat and mouse imaging, the preferred animal models for research in biology, while achieving a sensitivity adequate for real-time measurement of rapid dynamic processes in vivo without violating tracer kinetic principles. An overview of the current state of development of dedicated small animal PET scanners is given, and selected applications are reported and discussed with respect to performance and significance to research in biology.

  2. Molecular Imaging with Small Animal PET/CT

    DEFF Research Database (Denmark)

    Binderup, T.; El-Ali, H.H.; Skovgaard, D.;

    2011-01-01

    Small animal positron emission tomography (PET) and computer tomography (CT) is an emerging field in pre-clinical imaging. High quality, state-of-the-art instruments are required for full optimization of the translational value of the small animal studies with PET and CT. However, with this achie...... small animal PET/CT for studies of muscle and tendon in exercise models. © 2011 Bentham Science Publishers Ltd.......Small animal positron emission tomography (PET) and computer tomography (CT) is an emerging field in pre-clinical imaging. High quality, state-of-the-art instruments are required for full optimization of the translational value of the small animal studies with PET and CT. However, with this...... this field of small animal molecular imaging with special emphasis on the targets for tissue characterization in tumor biology such as hypoxia, proliferation and cancer specific over-expression of receptors. The added value of applying CT imaging for anatomical localization and tumor volume...

  3. Monte Carlo simulations in small animal PET imaging

    International Nuclear Information System (INIS)

    This work is based on the use of an implemented Positron Emission Tomography (PET) simulation system dedicated for small animal PET imaging. Geant4 Application for Tomographic Emission (GATE), a Monte Carlo simulation platform based on the Geant4 libraries, is well suited for modeling the microPET FOCUS system and to implement realistic phantoms, such as the MOBY phantom, and data maps from real examinations. The use of a microPET FOCUS simulation model with GATE has been validated for spatial resolution, counting rates performances, imaging contrast recovery and quantitative analysis. Results from realistic studies of the mouse body using -F and [18F]FDG imaging protocols are presented. These simulations include the injection of realistic doses into the animal and realistic time framing. The results have shown that it is possible to simulate small animal PET acquisitions under realistic conditions, and are expected to be useful to improve the quantitative analysis in PET mouse body studies

  4. Monte Carlo simulations in small animal PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Branco, Susana [Universidade de Lisboa, Faculdade de Ciencias, Instituto de Biofisica e Engenharia Biomedica, Lisbon (Portugal)], E-mail: susana.silva@fc.ul.pt; Jan, Sebastien [Service Hospitalier Frederic Joliot, CEA/DSV/DRM, Orsay (France); Almeida, Pedro [Universidade de Lisboa, Faculdade de Ciencias, Instituto de Biofisica e Engenharia Biomedica, Lisbon (Portugal)

    2007-10-01

    This work is based on the use of an implemented Positron Emission Tomography (PET) simulation system dedicated for small animal PET imaging. Geant4 Application for Tomographic Emission (GATE), a Monte Carlo simulation platform based on the Geant4 libraries, is well suited for modeling the microPET FOCUS system and to implement realistic phantoms, such as the MOBY phantom, and data maps from real examinations. The use of a microPET FOCUS simulation model with GATE has been validated for spatial resolution, counting rates performances, imaging contrast recovery and quantitative analysis. Results from realistic studies of the mouse body using {sup -}F and [{sup 18}F]FDG imaging protocols are presented. These simulations include the injection of realistic doses into the animal and realistic time framing. The results have shown that it is possible to simulate small animal PET acquisitions under realistic conditions, and are expected to be useful to improve the quantitative analysis in PET mouse body studies.

  5. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær;

    2012-01-01

    performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7) were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II). CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity...... bladder 18 ± 3% (15–21%). The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of...... the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction....

  6. Development of a PET scanner for simultaneously imaging small animals with MRI and PET.

    Science.gov (United States)

    Thompson, Christopher J; Goertzen, Andrew L; Thiessen, Jonathan D; Bishop, Daryl; Stortz, Greg; Kozlowski, Piotr; Retière, Fabrice; Zhang, Xuezhu; Sossi, Vesna

    2014-01-01

    Recently, positron emission tomography (PET) is playing an increasingly important role in the diagnosis and staging of cancer. Combined PET and X-ray computed tomography (PET-CT) scanners are now the modality of choice in cancer treatment planning. More recently, the combination of PET and magnetic resonance imaging (MRI) is being explored in many sites. Combining PET and MRI has presented many challenges since the photo-multiplier tubes (PMT) in PET do not function in high magnetic fields, and conventional PET detectors distort MRI images. Solid state light sensors like avalanche photo-diodes (APDs) and more recently silicon photo-multipliers (SiPMs) are much less sensitive to magnetic fields thus easing the compatibility issues. This paper presents the results of a group of Canadian scientists who are developing a PET detector ring which fits inside a high field small animal MRI scanner with the goal of providing simultaneous PET and MRI images of small rodents used in pre-clinical medical research. We discuss the evolution of both the crystal blocks (which detect annihilation photons from positron decay) and the SiPM array performance in the last four years which together combine to deliver significant system performance in terms of speed, energy and timing resolution. PMID:25120157

  7. Development of a PET Scanner for Simultaneously Imaging Small Animals with MRI and PET

    Directory of Open Access Journals (Sweden)

    Christopher J Thompson

    2014-08-01

    Full Text Available Recently, positron emission tomography (PET is playing an increasingly important role in the diagnosis and staging of cancer. Combined PET and X-ray computed tomography (PET-CT scanners are now the modality of choice in cancer treatment planning. More recently, the combination of PET and magnetic resonance imaging (MRI is being explored in many sites. Combining PET and MRI has presented many challenges since the photo-multiplier tubes (PMT in PET do not function in high magnetic fields, and conventional PET detectors distort MRI images. Solid state light sensors like avalanche photo-diodes (APDs and more recently silicon photo-multipliers (SiPMs are much less sensitive to magnetic fields thus easing the compatibility issues. This paper presents the results of a group of Canadian scientists who are developing a PET detector ring which fits inside a high field small animal MRI scanner with the goal of providing simultaneous PET and MRI images of small rodents used in pre-clinical medical research. We discuss the evolution of both the crystal blocks (which detect annihilation photons from positron decay and the SiPM array performance in the last four years which together combine to deliver significant system performance in terms of speed, energy and timing resolution.

  8. Importance of Attenuation Correction (AC for Small Animal PET Imaging

    Directory of Open Access Journals (Sweden)

    Henrik H. El Ali

    2012-10-01

    Full Text Available The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7 were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II. CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%, for kidneys 20 ± 1% (19–21%, and for bladder 18 ± 3% (15–21%. The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction.

  9. Performance Evaluation of microPET: A High-Resolution Lutetium Oxyorthosilicate PET Scanner for Animal Imaging

    OpenAIRE

    Chatziioannou, Arion F.; Cherry, Simon R.; Shao, Yiping; Silverman, Robert W.; Meadors, Ken; Farquhar, Thomas H.; Pedarsani, Marjan; Phelps, Michael E.

    1999-01-01

    A new dedicated PET scanner, microPET, was designed and developed at the University of California, Los Angeles, for imaging small laboratory animals. The goal was to provide a compact system with superior spatial resolution at a fraction of the cost of a clinical PET scanner.

  10. Multimodal imaging of orthotopic hepatocellular carcinoma using small animal PET, bioluminescence and contrast enhanced CT imaging

    International Nuclear Information System (INIS)

    Molecular imaging with small-animal PET and bioluminescence imaging has been used as an important tool in cancer research. One of the disadvantages of these imaging modalities is the lack of anatomic information. To obtain fusion images with both molecular and anatomical information, small-animal PET and bioluminescence images fused with contrast enhance CT image in orthotopic hepatocellular carcinoma (HCC) model. We retrovially transfected dual gene (HSV1-tk and firefly luciferase) to morris hepatoma cells. The expression of HSV1-tk and luciferase was checked by optical imager and in vitro radiolabeled FIAU uptake, respectively and also checked by RT-PCR analysis. MCA-TL cells (5X105/ 0.05 ml) mixed with matrigel (1: 10) injected into left lobe of liver in nude mice. 124I-FIAU-PET, bioluminescence and contrast enhanced CT images were obtained in the orthotopic HCC model and digital whole body autoradiography (DWBA) was performed. Small animal PET image was obtained at 2 h post injection of 124I-FIAU and contrast enhanced CT image was obtained at 3 h post injection of Fenestra LC (0.3 ml). MCA-TL cells showed more specific 124I-FIAU uptake and higher luminescent activity than parental cells. The orthotopic HCC was detected by 124I-FIAU PET, contrast enhanced CT, and BLI and confirmed by DWBA. Registered image in orthotopic HCC t models showed a good correlation of images from both PET and CT. Contrast enhanced CT image delineated margin of HCC. Multimodal imaging with 124I-FIAU PET, bioluminescence and contrast enhanced CT allows a precise and improved detection of tumor in orthotopic hepatocellular carcinoma model. Multimodal imaging is potentially useful for monitoring progression of hepatic metastasis and for the evaluation of cancer treatments

  11. Development of a SiPM-based PET imaging system for small animals

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanye [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Yang, Kun, E-mail: yangkun9999@hotmail.com [Department of Control Technology and Instrumentation, College of Quality and Technical Supervision, Hebei University, Baoding, 071000 (China); Zhou, Kedi; Zhang, Qiushi; Pang, Bo [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Ren, Qiushi, E-mail: renqsh@coe.pku.edu.cn [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China)

    2014-04-11

    Advances in small animal positron emission tomography (PET) imaging have been accelerated by many new technologies such as the successful incorporation of silicon photomultiplier (SiPM). In this paper, we have developed a compact, lightweight PET imaging system that is based on SiPM detectors for small animals imaging, which could be integrated into a multi-modality imaging system. This PET imaging system consists of a stationary detector gantry, a motor-controlled animal bed module, electronics modules, and power supply modules. The PET detector, which was designed as a multi-slice circular ring geometry of 27 discrete block detectors, is composed of a cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal and SiPM arrays. The system has a 60 mm transaxial field of view (FOV) and a 26 mm axial FOV. Performance tests (e.g. spatial resolution, energy resolution, and sensitivity) and phantom and animal imaging studies were performed to evaluate the imaging performance of the PET imaging system. The performance tests and animal imaging results demonstrate the feasibility of an animal PET system based on SiPM detectors and indicate that SiPM detectors can be promising photodetectors in animal PET instrumentation development.

  12. Development of a SiPM-based PET imaging system for small animals

    International Nuclear Information System (INIS)

    Advances in small animal positron emission tomography (PET) imaging have been accelerated by many new technologies such as the successful incorporation of silicon photomultiplier (SiPM). In this paper, we have developed a compact, lightweight PET imaging system that is based on SiPM detectors for small animals imaging, which could be integrated into a multi-modality imaging system. This PET imaging system consists of a stationary detector gantry, a motor-controlled animal bed module, electronics modules, and power supply modules. The PET detector, which was designed as a multi-slice circular ring geometry of 27 discrete block detectors, is composed of a cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal and SiPM arrays. The system has a 60 mm transaxial field of view (FOV) and a 26 mm axial FOV. Performance tests (e.g. spatial resolution, energy resolution, and sensitivity) and phantom and animal imaging studies were performed to evaluate the imaging performance of the PET imaging system. The performance tests and animal imaging results demonstrate the feasibility of an animal PET system based on SiPM detectors and indicate that SiPM detectors can be promising photodetectors in animal PET instrumentation development

  13. The motivations and methodology for high-throughput PET imaging of small animals in cancer research

    OpenAIRE

    Aide, Nicolas; Visser, Eric P.; Lheureux, Stéphanie; Heutte, Natacha; Szanda, Istvan; Hicks, Rodney J.

    2012-01-01

    Over the last decade, small-animal PET imaging has become a vital platform technology in cancer research. With the development of molecularly targeted therapies and drug combinations requiring evaluation of different schedules, the number of animals to be imaged within a PET experiment has increased. This paper describes experimental design requirements to reach statistical significance, based on the expected change in tracer uptake in treated animals as compared to the control group, the num...

  14. Evaluation of the respiratory motion effect in small animal PET images with GATE Monte Carlo simulations

    OpenAIRE

    Branco, Susana; Almeida, Pedro; Jan, Sébastien

    2011-01-01

    The rapid growth in genetics and molecular biology combined with the development of techniques for genetically engineering small animals has led to increased interest in in vivo small animal imaging. Small animal imaging has been applied frequently to the imaging of small animals (mice and rats), which are ubiquitous in modeling human diseases and testing treatments. The use of PET in small animals allows the use of subjects as their own control, reducing the interanimal variability....

  15. The motivations and methodology for high-throughput PET imaging of small animals in cancer research

    Energy Technology Data Exchange (ETDEWEB)

    Aide, Nicolas [Francois Baclesse Cancer Centre, Nuclear Medicine Department, Caen Cedex (France); Caen University, BioTICLA team, EA 4656, IFR 146, Caen (France); Visser, Eric P. [Radboud University Nijmegen Medical Center, Nuclear Medicine Department, Nijmegen (Netherlands); Lheureux, Stephanie [Caen University, BioTICLA team, EA 4656, IFR 146, Caen (France); Francois Baclesse Cancer Centre, Clinical Research Unit, Caen (France); Heutte, Natacha [Francois Baclesse Cancer Centre, Clinical Research Unit, Caen (France); Szanda, Istvan [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Hicks, Rodney J. [Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne (Australia)

    2012-09-15

    Over the last decade, small-animal PET imaging has become a vital platform technology in cancer research. With the development of molecularly targeted therapies and drug combinations requiring evaluation of different schedules, the number of animals to be imaged within a PET experiment has increased. This paper describes experimental design requirements to reach statistical significance, based on the expected change in tracer uptake in treated animals as compared to the control group, the number of groups that will be imaged, and the expected intra-animal variability for a given tracer. We also review how high-throughput studies can be performed in dedicated small-animal PET, high-resolution clinical PET systems and planar positron imaging systems by imaging more than one animal simultaneously. Customized beds designed to image more than one animal in large-bore small-animal PET scanners are described. Physics issues related to the presence of several rodents within the field of view (i.e. deterioration of spatial resolution and sensitivity as the radial and the axial offsets increase, respectively, as well as a larger effect of attenuation and the number of scatter events), which can be assessed by using the NEMA NU 4 image quality phantom, are detailed. (orig.)

  16. The motivations and methodology for high-throughput PET imaging of small animals in cancer research

    International Nuclear Information System (INIS)

    Over the last decade, small-animal PET imaging has become a vital platform technology in cancer research. With the development of molecularly targeted therapies and drug combinations requiring evaluation of different schedules, the number of animals to be imaged within a PET experiment has increased. This paper describes experimental design requirements to reach statistical significance, based on the expected change in tracer uptake in treated animals as compared to the control group, the number of groups that will be imaged, and the expected intra-animal variability for a given tracer. We also review how high-throughput studies can be performed in dedicated small-animal PET, high-resolution clinical PET systems and planar positron imaging systems by imaging more than one animal simultaneously. Customized beds designed to image more than one animal in large-bore small-animal PET scanners are described. Physics issues related to the presence of several rodents within the field of view (i.e. deterioration of spatial resolution and sensitivity as the radial and the axial offsets increase, respectively, as well as a larger effect of attenuation and the number of scatter events), which can be assessed by using the NEMA NU 4 image quality phantom, are detailed. (orig.)

  17. Scatter Characterization and Correction for Simultaneous Multiple Small-Animal PET Imaging

    NARCIS (Netherlands)

    Prasad, Rameshwar; Zaidi, Habib

    2014-01-01

    The rapid growth and usage of small-animal positron emission tomography (PET) in molecular imaging research has led to increased demand on PET scanner's time. One potential solution to increase throughput is to scan multiple rodents simultaneously. However, this is achieved at the expense of deterio

  18. Automated method for small-animal PET image registration with intrinsic validation

    OpenAIRE

    Pascau, Javier; Gispert, Juan Domingo; Michaelides, Michael; Thanos, Panayotis K.; Volkow, Nora D.; Vaquero, Juan José; Soto-Montenegro, Maria Luisa; Desco, Manuel

    2009-01-01

    We propose and compare different registration approaches to align small-animal PET studies and a procedure to validate the results by means of objective registration consistency measurements. Procedures: We have applied a registration algorithm based on information theory, using different approaches to mask the reference image. The registration consistency allows for the detection of incorrect registrations. This methodology has been evaluated on a test dataset(FDG-PET rat brain images)...

  19. A combined micro-PET/CT scanner for small animal imaging

    International Nuclear Information System (INIS)

    A micro-PET/CT system was developed by combination of an in-house micro-CT and a microPET[reg] R4 scanner. The cone-beam micro-CT consists of a rotational gantry that fits an X-ray tube, a CCD-based X-ray detector, and motor-driven linear stages. The gantry was designed to be coaxial with the scanner of microPET'' (registered) R4. It can be moved for the convenience of mounting the Ge-68 point-source holder for PET's calibration. The image volumes obtained from two modalities is registered by a pre-determined, inherent spatial transformation function. This hardware-approach fusion, which provides accurate and no labor-intensive alignment, is suitable for mass scanning. The micro-PET/CT system has been operated successfully. Merging the anatomical and functional images benefit studies of the small animal imaging

  20. Feasibility study of small animal imaging using clinical PET/CT scanner

    Science.gov (United States)

    Hsu, Wen-Lin; Chen, Chia-Lin; Wang, Ze-Jing; Wu, Tung-Hsin; Liu, Dai-Wei; Lee, Jason J. S.

    2007-02-01

    The feasibility of small animal imaging using a clinical positron emission tomography/computed tomography (PET/CT) scanner with [F-18]-fluoro-2-deoxy- D-glucose (FDG) was evaluated. Two protocols in PET/CT system, single-mouse high-resolution mode (SHR) and multi-mouse high throughput mode (MHT) protocol were employed to investigate the ability of the scanner and also explored the performance differences between microPET and clinical PET/CT. In this study, we have found that even the clinical PET/CT scanner could not compete with the microPET scanner, especially in spatial resolution; the high-resolution CT image could advance the anatomical information to sub-millimeter level. Besides, CT-based attenuation correction can improve the image uniformity characteristics and quantification accuracy, and the large bore of a human whole-body scanner broadens the possibility of high throughput studies. Considering all the benefits, clinical PET/CT imaging might be a potential alternative for small animal study.

  1. [2D imaging simulations of a small animal PET scanner with DOI measurement: jPET-RD.].

    Science.gov (United States)

    Yamaya, Taiga; Kitamura, Keishi; Hagiwara, Naoki; Obi, Takashi; Hasegawa, Tomoyuki; Yoshida, Eiji; Tsuda, Tomoaki; Inadama, Naoko; Wada, Yasuhiro; Murayama, Hideo

    2005-01-01

    We present a preliminary study on the design of a high sensitivity small animal DOI-PET scanner: jPET-RD (for Rodents with DOI detectors), which will contribute to molecular imaging. The 4-layer DOI block detector for the jPET-RD that consists of scintillation crystals (1.4 mm x 1.4 mm x 4.5 mm) and a flat panel position-sensitive photomultiplier tube (52 mm x 52 mm) was previously proposed. In this paper, we investigate imaging performance of the jPET-RD through numerical simulations. The scanner has a hexagonal geometry with a small diameter and a large axial aperture. Therefore DOI information is expected to improve resolution uniformity in the whole field of view (FOV). We simulate the scanner for various parameters of the number of DOI channels and the crystal length. Simulated data are reconstructed using the maximum likelihood expectation maximization with accurate system modeling. The trade-off results between background noise and spatial resolution show that only shortening the length of crystal does not improve the trade-off at all, and that 4-layer DOI information improves uniformity of spatial resolution in the whole FOV. Excellent performance of the jPET-RD can be expected based on the numerical simulation results. PMID:15961924

  2. High throughput static and dynamic small animal imaging using clinical PET/CT: potential preclinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Aide, Nicolas [Francois Baclesse Cancer Centre and Caen University, Bioticla Team, EA1792, IFR 146 ICORE, GRECAN, Caen (France); Caen University Hospital and Francois Baclesse Cancer Centre, PET Unit, Caen (France); Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne (Australia); Centre Francois Baclesse, Nuclear Medicine Department, Caen cedex 5 (France); Desmonts, Cedric; Agostini, Denis; Bardet, Stephane; Bouvard, Gerard [Caen University Hospital and Francois Baclesse Cancer Centre, PET Unit, Caen (France); Beauregard, Jean-Mathieu; Roselt, Peter; Neels, Oliver [Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne (Australia); Beyer, Thomas [cmi-experts GmbH, Zurich (Switzerland); University Hospital Essen, Department of Nuclear Medicine, Essen (Germany); University Hospital Bern, Institute of Nuclear Medicine, Bern (Switzerland); Kinross, Kathryn [Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne (Australia); Peter MacCallum Cancer Centre, Sir Donald and Lady Trescowthick Laboratories, East Melbourne (Australia); Hicks, Rodney J. [Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne (Australia); University of Melbourne, The Department of Medicine, Parkville (Australia)

    2010-05-15

    The objective of the study was to evaluate state-of-the-art clinical PET/CT technology in performing static and dynamic imaging of several mice simultaneously. A mouse-sized phantom was imaged mimicking simultaneous imaging of three mice with computation of recovery coefficients (RCs) and spillover ratios (SORs). Fifteen mice harbouring abdominal or subcutaneous tumours were imaged on clinical PET/CT with point spread function (PSF) reconstruction after injection of [18F]fluorodeoxyglucose or [18F]fluorothymidine. Three of these mice were imaged alone and simultaneously at radial positions -5, 0 and 5 cm. The remaining 12 tumour-bearing mice were imaged in groups of 3 to establish the quantitative accuracy of PET data using ex vivo gamma counting as the reference. Finally, a dynamic scan was performed in three mice simultaneously after the injection of {sup 68}Ga-ethylenediaminetetraacetic acid (EDTA). For typical lesion sizes of 7-8 mm phantom experiments indicated RCs of 0.42 and 0.76 for ordered subsets expectation maximization (OSEM) and PSF reconstruction, respectively. For PSF reconstruction, SOR{sub air} and SOR{sub water} were 5.3 and 7.5%, respectively. A strong correlation (r {sup 2} = 0.97, p < 0.0001) between quantitative data obtained in mice imaged alone and simultaneously in a group of three was found following PSF reconstruction. The correlation between ex vivo counting and PET/CT data was better with PSF reconstruction (r {sup 2} = 0.98; slope = 0.89, p < 0.0001) than without (r {sup 2} = 0.96; slope = 0.62, p < 0.001). Valid time-activity curves of the blood pool, kidneys and bladder could be derived from {sup 68}Ga-EDTA dynamic acquisition. New generation clinical PET/CT can be used for simultaneous imaging of multiple small animals in experiments requiring high throughput and where a dedicated small animal PET system is not available. (orig.)

  3. Kinetic parametric estimation in animal PET molecular imaging based on artificial immune network

    International Nuclear Information System (INIS)

    Objective: To develop an accurate,reliable method without the need of initialization in animal PET modeling for estimation of the tracer kinetic parameters based on the artificial immune network. Methods: The hepatic and left ventricular time activity curves (TACs) were obtained by drawing ROIs of liver tissue and left ventricle on dynamic 18F-FDG PET imaging of small mice. Meanwhile, the blood TAC was analyzed by sampling the tail vein blood at different time points after injection. The artificial immune network for parametric optimization of pharmacokinetics (PKAIN) was adapted to estimate the model parameters and the metabolic rate of glucose (Ki) was calculated. Results: TACs of liver,left ventricle and tail vein blood were obtained.Based on the artificial immune network, Ki in 3 mice was estimated as 0.0024, 0.0417 and 0.0047, respectively. The average weighted residual sum of squares of the output model generated by PKAIN was less than 0.0745 with a maximum standard deviation of 0.0084, which indicated that the proposed PKAIN method can provide accurate and reliable parametric estimation. Conclusion: The PKAIN method could provide accurate and reliable tracer kinetic modeling in animal PET imaging without the need of initialization of model parameters. (authors)

  4. Contribution of normalization to image noise for the Siemens Inveon small-animal PET scanner

    International Nuclear Information System (INIS)

    Due to the large number of detector elements (25,600 crystals) and lines of response (LOR) (88,453,120), normalization of the Siemens Inveon small-animal PET scanner can introduce additional image noise when using the standard, individual LOR-based normalization (ILORNORM) of 10 h scan duration. Recently, component-based normalization (CNORM) has been made available for this scanner. The aim of this study was to compare the performance of both normalization algorithms and to determine the minimum time needed for a normalization scan. Normalization scans of 1 min up to 115 h were performed. Reconstructed image noise was determined using the FDG-filled NEMA NU-4 small-animal PET image quality phantom. CNORM significantly reduced image noise as compared to ILORNORM. For CNORM, the scan duration could even be reduced to 10 min without deterioration of reconstructed image quality. Such a short scan duration implies that scanner normalization can easily be incorporated in daily or weekly quality control procedures.

  5. Contribution of normalization to image noise for the Siemens Inveon small-animal PET scanner

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Eric P. [Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (Netherlands)], E-mail: e.visser@nucmed.umcn.nl; Disselhorst, Jonathan A.; Laverman, Peter; Gotthardt, Martin; Oyen, Wim J.G.; Boerman, Otto C. [Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen (Netherlands)

    2009-07-01

    Due to the large number of detector elements (25,600 crystals) and lines of response (LOR) (88,453,120), normalization of the Siemens Inveon small-animal PET scanner can introduce additional image noise when using the standard, individual LOR-based normalization (ILORNORM) of 10 h scan duration. Recently, component-based normalization (CNORM) has been made available for this scanner. The aim of this study was to compare the performance of both normalization algorithms and to determine the minimum time needed for a normalization scan. Normalization scans of 1 min up to 115 h were performed. Reconstructed image noise was determined using the FDG-filled NEMA NU-4 small-animal PET image quality phantom. CNORM significantly reduced image noise as compared to ILORNORM. For CNORM, the scan duration could even be reduced to 10 min without deterioration of reconstructed image quality. Such a short scan duration implies that scanner normalization can easily be incorporated in daily or weekly quality control procedures.

  6. A 3D HIDAC-PET camera with sub-millimeter resolution for imaging small animals

    International Nuclear Information System (INIS)

    A HIDAC-PET camera consisting essentially of 5 million 0.5 mm gas avalanching detectors has been constructed for small-animal imaging. The particular HIDAC advantage--a high 3D spatial resolution--has been improved to 0.95 mm fwhm and to 0.7 mm fwhm when reconstructing with 3D-OSEM methods incorporating resolution recovery. A depth-of-interaction resolution of 2.5 mm is implicit, due to the laminar construction. Scatter-corrected sensitivity, at 8.9 cps/kBq (i.e. 0.9%) from a central point source, or 7.2 cps/kBq (543 cps/kBq/cm3) from a distributed (40 mm diameter, 60 mm long) source is now much higher than previous, and other, work. A field-of-view of 100 mm (adjustable to 200 mm) diameter by 210 mm axially permits whole-body imaging of small animals, containing typically 4MBqs of activity, at 40 kcps of which 16% are random coincidences, with a typical scatter fraction of 44%. Throughout the field-of-view there are no positional distortions and relative quantitation is uniform to ± 3.5%, but some variation of spatial resolution is found. The performance demonstrates that HIDAC technology is quite appropriate for small-animal PET cameras

  7. Noise reduction in small-animal PET images using a multiresolution transform.

    Science.gov (United States)

    Mejia, Jose M; Ochoa Domínguez, Humberto de Jesús; Vergara Villegas, Osslan Osiris; Ortega Máynez, Leticia; Mederos, Boris

    2014-10-01

    In this paper, we address the problem of denoising reconstructed small animal positron emission tomography (PET) images, based on a multiresolution approach which can be implemented with any transform such as contourlet, shearlet, curvelet, and wavelet. The PET images are analyzed and processed in the transform domain by modeling each subband as a set of different regions separated by boundaries. Homogeneous and heterogeneous regions are considered. Each region is independently processed using different filters: a linear estimator for homogeneous regions and a surface polynomial estimator for the heterogeneous region. The boundaries between the different regions are estimated using a modified edge focusing filter. The proposed approach was validated by a series of experiments. Our method achieved an overall reduction of up to 26% in the %STD of the reconstructed image of a small animal NEMA phantom. Additionally, a test on a simulated lesion showed that our method yields better contrast preservation than other state-of-the art techniques used for noise reduction. Thus, the proposed method provides a significant reduction of noise while at the same time preserving contrast and important structures such as lesions. PMID:24951682

  8. Quantitative assessment of small animal cardiac 18F-FDG PET and MRI image

    International Nuclear Information System (INIS)

    Cardiac disease research relies increasingly on small animal models and non-invasive imaging methods such as positron emission tomography (PET) and magnetic resonance imaging (MRI). Delayed enhancement magnetic resonance imaging (DE-MRI) using gadolinium-based contrast agents appear to be a visualizing infracted myocardium with high spatial resolution. Polar map (or bull's-eye image) was used to determination of the myocardial infarction area. Polar map is a comprehensive interpretation of the left ventricle. The infarct size was computed as the fraction of the total polar map areas. The threshold was computed as the percentage of mean intensity of the normal region. In other study, 50% predefined threshold value in varying range (30∼70%) was most commonly use. However, predefined threshold value isn't acceptance in all case. The purpose of this study was to investigate methodological approach for automatic measurement of rat myocardial infarct size using PET and MRI polar map with adaptive threshold value driven from Multi gaussian mixture model (MGMM)

  9. Application of a semi-automatic ROI setting system for brain PET images to animal PET studies

    International Nuclear Information System (INIS)

    ProASSIST, a semi-automatic ROI (region of interest) setting system for human brain PET images, has been modified for use with the canine brain, and the performance of the obtained system was evaluated by comparing the operational simplicity for ROI setting and the consistency of ROI values obtained with those by a conventional manual procedure. Namely, we created segment maps for the canine brain by making reference to the coronal section atlas of the canine brain by Lim et al., and incorporated them into the ProASSIST system. For the performance test, CBF (cerebral blood flow) and CMRglc (cerebral metabolic rate in glucose) images in dogs with or without focal cerebral ischemia were used. In ProASSIST, brain contours were defined semiautomatically. In the ROI analysis of the test image, manual modification of the contour was necessary in half cases examined (8/16). However, the operation was rather simple so that the operation time per one brain section was significantly shorter than that in the manual operation. The ROI values determined by the system were comparable with those by the manual procedure, confirming the applicability of the system to these animal studies. The use of the system like the present one would also merit the more objective data acquisition for the quantitative ROI analysis, because no manual procedure except for some specifications of the anatomical features is required for ROI setting. (author)

  10. An investigation of the challenges in reconstructing PET images of a freely moving animal

    International Nuclear Information System (INIS)

    Imaging the brain of a freely moving small animal using positron emission tomography (PET) while simultaneously observing its behaviour is an important goal for neuroscience. While we have successfully demonstrated the use of line-of-response (LOR) rebinning to correct the head motion of confined animals, a large proportion of events may need to be discarded because they either 'miss' the detector array after transformation or fall out of the acceptance range of a sinogram. The proportion of events that would have been measured had motion not occurred, so-called 'lost events', is expected to be even larger for freely moving animals. Moreover, the data acquisition in the case of a freely moving animal is further complicated by a complex attenuation field. The aims of this study were (a) to characterise the severity of 'lost events' problem for the freely moving animal scenario, and (b) to investigate the relative impact of attenuation correction errors on quantitative accuracy of reconstructed images. A phantom study was performed to simulate the uncorrelated motion of a target and non-target source volume. A small animal PET scanner was used to acquire list-mode data for different sets of phantom positions. The list-mode data were processed using the standard LOR rebinning approach, and multiple frame variants of this designed to reduce discarded events. We found that LOR rebinning caused up to 86 % 'lost events', and artifacts that we attribute to incomplete projections, when applied to a freely moving target. This fraction was reduced by up to 18 % using the variant approaches, resulting in slightly reduced image artifacts. The effect of the non-target compartment on attenuation correction of the target volume was surprisingly small. However, for certain poses where the target and non-target volumes are aligned transaxially in the field-of-view, the attenuation problem becomes more complex and sophisticated correction methods will be required. We conclude that

  11. Improved automated synthesis and preliminary animal PET/CT imaging of 11C-acetate

    International Nuclear Information System (INIS)

    To study a simple and rapid automated synthetic technology of 11C-acetate (11C- AC), automated synthesis of 11C-AC was performed by carboxylation of MeMgBr/tetrahydrofuran (THF) on a polyethylene loop with 11C-CO2, followed by hydrolysis and purification on solid-phase extraction cartridges using a 11C-Choline/Methionine synthesizer made in China. A high and reproducible radiochemical yield of above 40% (decay corrected) was obtained within the whole synthesis time about 8 min from 11C-CO2. The radiochemical purity of 11C-AC was over 95%. The novel, simple and rapid on-column hydrolysis-purification procedure should adaptable to the fully automated synthesis of 11C-AC at several commercial synthesis module. 11C-AC injection produced by the automated procedure is safe and effective, and can be used for PET imaging of animals and humans. (authors)

  12. Performance evaluation of a compact PET/SPECT/CT tri-modality system for small animal imaging applications

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Qingyang [Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China); Wang, Shi [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China); Ma, Tianyu, E-mail: maty@tsinghua.edu.cn [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China); Wu, Jing; Liu, Hui; Xu, Tianpeng; Xia, Yan; Fan, Peng; Lyu, Zhenlei; Liu, Yaqiang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China)

    2015-06-21

    PET, SPECT and CT imaging techniques are widely used in preclinical small animal imaging applications. In this paper, we present a compact small animal PET/SPECT/CT tri-modality system. A dual-functional, shared detector design is implemented which enables PET and SPECT imaging with a same LYSO ring detector. A multi-pinhole collimator is mounted on the system and inserted into the detector ring in SPECT imaging mode. A cone-beam CT consisting of a micro focus X-ray tube and a CMOS detector is implemented. The detailed design and the performance evaluations are reported in this paper. In PET imaging mode, the measured NEMA based spatial resolution is 2.12 mm (FWHM), and the sensitivity at the central field of view (CFOV) is 3.2%. The FOV size is 50 mm (∅)×100 mm (L). The SPECT has a spatial resolution of 1.32 mm (FWHM) and an average sensitivity of 0.031% at the center axial, and a 30 mm (∅)×90 mm (L) FOV. The CT spatial resolution is 8.32 lp/mm @10%MTF, and the contrast discrimination function value is 2.06% with 1.5 mm size cubic box object. In conclusion, a compact, tri-modality PET/SPECT/CT system was successfully built with low cost and high performance.

  13. Performance evaluation of a compact PET/SPECT/CT tri-modality system for small animal imaging applications

    International Nuclear Information System (INIS)

    PET, SPECT and CT imaging techniques are widely used in preclinical small animal imaging applications. In this paper, we present a compact small animal PET/SPECT/CT tri-modality system. A dual-functional, shared detector design is implemented which enables PET and SPECT imaging with a same LYSO ring detector. A multi-pinhole collimator is mounted on the system and inserted into the detector ring in SPECT imaging mode. A cone-beam CT consisting of a micro focus X-ray tube and a CMOS detector is implemented. The detailed design and the performance evaluations are reported in this paper. In PET imaging mode, the measured NEMA based spatial resolution is 2.12 mm (FWHM), and the sensitivity at the central field of view (CFOV) is 3.2%. The FOV size is 50 mm (∅)×100 mm (L). The SPECT has a spatial resolution of 1.32 mm (FWHM) and an average sensitivity of 0.031% at the center axial, and a 30 mm (∅)×90 mm (L) FOV. The CT spatial resolution is 8.32 lp/mm @10%MTF, and the contrast discrimination function value is 2.06% with 1.5 mm size cubic box object. In conclusion, a compact, tri-modality PET/SPECT/CT system was successfully built with low cost and high performance

  14. Performance evaluation of a compact PET/SPECT/CT tri-modality system for small animal imaging applications

    Science.gov (United States)

    Wei, Qingyang; Wang, Shi; Ma, Tianyu; Wu, Jing; Liu, Hui; Xu, Tianpeng; Xia, Yan; Fan, Peng; Lyu, Zhenlei; Liu, Yaqiang

    2015-06-01

    PET, SPECT and CT imaging techniques are widely used in preclinical small animal imaging applications. In this paper, we present a compact small animal PET/SPECT/CT tri-modality system. A dual-functional, shared detector design is implemented which enables PET and SPECT imaging with a same LYSO ring detector. A multi-pinhole collimator is mounted on the system and inserted into the detector ring in SPECT imaging mode. A cone-beam CT consisting of a micro focus X-ray tube and a CMOS detector is implemented. The detailed design and the performance evaluations are reported in this paper. In PET imaging mode, the measured NEMA based spatial resolution is 2.12 mm (FWHM), and the sensitivity at the central field of view (CFOV) is 3.2%. The FOV size is 50 mm (∅)×100 mm (L). The SPECT has a spatial resolution of 1.32 mm (FWHM) and an average sensitivity of 0.031% at the center axial, and a 30 mm (∅)×90 mm (L) FOV. The CT spatial resolution is 8.32 lp/mm @10%MTF, and the contrast discrimination function value is 2.06% with 1.5 mm size cubic box object. In conclusion, a compact, tri-modality PET/SPECT/CT system was successfully built with low cost and high performance.

  15. Coincidence measurements on detectors for microPET II: A 1 mm3 resolution PET scanner for small animal imaging

    CERN Document Server

    Chatziioannou, A; Shao, Y; Doshi, N K; Silverman, B; Meadors, K; Cherry, SR

    2000-01-01

    We are currently developing a small animal PET scanner with a design goal of 1 mm3 image resolution. We have built three pairs of detectors and tested performance in terms of crystal identification, spatial, energy and timing resolution. The detectors consisted of 12 multiplied by 12 arrays of 1 multiplied by 1 multiplied by 10mm LSO crystals (1.15 mm pitch) coupled to Hamamatsu H7546 64 channel PMTs via 5cm long coherent glass fiber bundles. Optical fiber connection is necessary to allow high packing fraction in a ring geometry scanner. Fiber bundles with and without extramural absorber (EMA) were tested. The results demonstrated an intrinsic spatial resolution of 1.12 mm (direct coupled LSO array), 1.23 mm (bundle without EMA) and 1.27 mm (bundle with EMA) using a similar to 500 micron diameter Na-22 source. Using a 330 micron line source filled with F-18, intrinsic resolution for the EMA bundle improved to 1.05 mm. The respective timing and energy resolution values were 1.96 ns, 21% (direct coupled), 2.20 ...

  16. Non-Invasive imaging of small-animal tumors: high-frequency ultrasound vs. MicroPET.

    Science.gov (United States)

    Liao, Ai-Ho; Li, Chen-Han; Cheng, Weng-Fang; Li, Pai-Chi

    2005-01-01

    Tumor volume measurement on small animals is important but currently invasive. We employ ultrasonic micro-imaging (UMI) in this study and demonstrate its feasibility. In addition, we use small animal positron emission tomography (microPET) as a preliminary effort to develop multi-modality small animal imaging techniques. The tumor growth curve from UMI is also compared to radioactivity from microPET. Both UMI and [18F] FDG microPET imaging were performed on C57BL/6J black mice bearing WF-3 ovary cancer cells at various stages from the second week till up to the eighth week. Segmentation and 3D reconstruction were also done. The growth curve was obtained in vivo noninvasively by UMI. The cell doubling time was 7.46 days according to UMI. This result was compared with vernier caliper measurement and radioactivity counting by microPET. In microPET, we obtained the time-activity curves from the tumor and the tumor-surrounding tissue. The tumor-to-normal-tissues ratios reached maximum at the fifth week after tumor cell implantation. PMID:17281549

  17. Anesthesia condition for {sup 18}F-FDG imaging of lung metastasis tumors using small animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sang-Keun; Lee, Tae Sup; Kim, Kyeong Min; Kim, June-Youp; Jung, Jae Ho; Kang, Joo Hyun [Division of Nuclear Medicine and RI Application, Korea Institute of Radiological and Medical Sciences (KIRAMS), Nowon-Gu, Seoul 139-706 (Korea, Republic of); Cheon, Gi Jeong [Division of Nuclear Medicine and RI Application, Korea Institute of Radiological and Medical Sciences (KIRAMS), Nowon-Gu, Seoul 139-706 (Korea, Republic of); Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences (KIRAMS), Nowon-Gu, Seoul 139-706 (Korea, Republic of)], E-mail: larry@kcch.re.kr; Choi, Chang Woon; Lim, Sang Moo [Division of Nuclear Medicine and RI Application, Korea Institute of Radiological and Medical Sciences (KIRAMS), Nowon-Gu, Seoul 139-706 (Korea, Republic of); Department of Nuclear Medicine, Korea Institute of Radiological and Medical Sciences (KIRAMS), Nowon-Gu, Seoul 139-706 (Korea, Republic of)

    2008-01-15

    Small animal positron emission tomography (PET) with {sup 18}F-FDG has been increasingly used for tumor imaging in the murine model. The aim of this study was to establish the anesthesia condition for imaging of lung metastasis tumor using small animal {sup 18}F-FDG PET. Methods: To determine the impact of anesthesia on {sup 18}F-FDG distribution in normal mice, five groups were studied under the following conditions: no anesthesia, ketamine and xylazine (Ke/Xy), 0.5% isoflurane (Iso 0.5), 1% isoflurane (Iso 1) and 2% isoflurane (Iso 2). The ex vivo counting, standard uptake value (SUV) image and glucose SUV of {sup 18}F-FDG in various tissues were evaluated. The {sup 18}F-FDG images in the lung metastasis tumor model were obtained under no anesthesia, Ke/Xy and Iso 0.5, and registered with CT image to clarify the tumor region. Results: Blood glucose concentration and muscle uptake of {sup 18}F-FDG in the Ke/Xy group markedly increased more than in the other groups. The Iso 2 group increased {sup 18}F-FDG uptake in heart compared with the other groups. The Iso 0.5 anesthesized group showed the lowest {sup 18}F-FDG uptake in heart and chest wall. The small size of lung metastasis tumor (2 mm) was clearly visualized by {sup 18}F-FDG image with the Iso 0.5 anesthesia. Conclusion: Small animal {sup 18}F-FDG PET imaging with Iso 0.5 anesthesia was appropriate for the detection of lung metastasis tumor. To acquire {sup 18}F-FDG PET images with small animal PET, the type and level of anesthetic should be carefully considered to be suitable for the visualization of target tissue in the experimental model.

  18. Imaging of lung metastasis tumor mouse model using [{sup 18}F]FDG small animal PET and CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, June Youp; Woo, Sang Keun; Lee, Tae Sup [Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul (Korea, Republic of)] (and others)

    2007-02-15

    The purpose of this study is to image metastaic lung melanoma model with optimal pre-conditions for animal handling by using [{sup 18}F]FDG small animal PET and clinical CT. The pre-conditions for lung region tumor imaging were 16-22 h fasting and warming temperature at 30 .deg. C. Small animal PET image was obtained at 60 min postinjection of 7.4 MBq [{sup 18}F]FDG and compared pattern of [{sup 18}F]FDG uptake and glucose standard uptake value (SUVG) of lung region between Ketamine/Xylazine (Ke/Xy) and Isoflurane (Iso) anesthetized group in normal mice. Metastasis tumor mouse model to lung was established by intravenous injection of B16-F10 cells in C57BL/6 mice. In lung metastasis tumor model, [{sup 18}F]FDG image was obtained and fused with anatomical clinical CT image. Average blood glucose concentration in normal mice were 128.0 {+-} 22.87 and 86.0 {+-} 21.65 mg/dL in Ke/Xy group and Iso group, respectively. Ke/Xy group showed 1.5 fold higher blood glucose concentration than Iso group. Lung to Background ratio (L/B) in SUVG image was 8.6 {+-} 0.48 and 12.1 {+-}0.63 in Ke/Xy group and Iso group, respectively. In tumor detection in lung region, [{sup 18}F]FDG image of Iso group was better than that of Ke/Xy group, because of high L/B ratio. Metastatic tumor location in [{sup 18}F]FDG small animal PET image was confirmed by fusion image using clinical CT. Tumor imaging in small animal lung region with [{sup 18}F]FDG small animal PET should be considered pre-conditions which fasting, warming and an anesthesia during [{sup 18}F]FDG uptake. Fused imaging with small animal PET and CT image could be useful for the detection of metastatic tumor in lung region.

  19. MicroPET II: design, development and initial performance of an improved microPET scanner for small-animal imaging

    OpenAIRE

    Tai, Y. C.; Chatziioannou, A. F.; Yang, Y. F.; Silverman, R W; Meadors, K; Siegel, S.; Newport, D F; Stickel, J R; Cherry, Simon R.

    2003-01-01

    MicroPET II is a second-generation animal PET scanner designed for high-resolution imaging of small laboratory rodents. The system consists of 90 scintillation detector modules arranged in three contiguous axial rings with a ring diameter of 16.0 cm and an axial length of 4.9 cm. Each detector module consists of a 14 x 14 array of lutetium oxyorthosilicate (LSO) crystals coupled to a multi-channel photomultiplier tube (MC-PMT) through a coherent optical fibre bundle. Each LSO crystal element ...

  20. DigiPET: sub-millimeter spatial resolution small-animal PET imaging using thin monolithic scintillators.

    Science.gov (United States)

    España, Samuel; Marcinkowski, Radoslaw; Keereman, Vincent; Vandenberghe, Stefaan; Van Holen, Roel

    2014-07-01

    A new preclinical PET system based on dSiPMs, called DigiPET, is presented. The system is based on thin monolithic scintillation crystals and exhibits superior spatial resolution at low-cost compared to systems based on pixelated crystals. Current dedicated small-rodent PET scanners have a spatial resolution in the order of 1 mm. Most of them have a large footprint, requiring considerable laboratory space. For rodent brain imaging, a PET scanner with sub-millimeter resolution is desired. To achieve this, crystals with a pixel pitch down to 0.5 mm have been used. However, fine pixels are difficult to produce and will render systems expensive. In this work, we present the first results with a high-resolution preclinical PET scanner based on thin monolithic scintillators and a large solid angle. The design is dedicated to rat-brain imaging and therefore has a very compact geometry. Four detectors were placed in a square arrangement with a distance of 34.5 mm between two opposing detector modules, defining a field of view (FOV) of 32 × 32 × 32 mm(3). Each detector consists of a thin monolithic LYSO crystal of 32 × 32 × 2 mm(3) optically coupled to a digital silicon photomultiplier (dSiPM). Event positioning within each detector was obtained using the maximum likelihood estimation (MLE) method. To evaluate the system performance, we measured the energy resolution, coincidence resolving time (CRT), sensitivity and spatial resolution. The image quality was evaluated by acquiring a hot-rod phantom filled with (18)F-FDG and a rat head one hour after an (18)F-FDG injection. The MLE yielded an average intrinsic spatial resolution on the detector of 0.54 mm FWHM. We obtained a CRT of 680 ps and an energy resolution of 18% FWHM at 511 keV. The sensitivity and spatial resolution obtained at the center of the FOV were 6.0 cps kBq(-1) and 0.7 mm, respectively. In the reconstructed images of the hot-rod phantom, hot rods down to 0.7 mm can be discriminated

  1. DigiPET: sub-millimeter spatial resolution small-animal PET imaging using thin monolithic scintillators

    International Nuclear Information System (INIS)

    A new preclinical PET system based on dSiPMs, called DigiPET, is presented. The system is based on thin monolithic scintillation crystals and exhibits superior spatial resolution at low-cost compared to systems based on pixelated crystals. Current dedicated small-rodent PET scanners have a spatial resolution in the order of 1 mm. Most of them have a large footprint, requiring considerable laboratory space. For rodent brain imaging, a PET scanner with sub-millimeter resolution is desired. To achieve this, crystals with a pixel pitch down to 0.5 mm have been used. However, fine pixels are difficult to produce and will render systems expensive. In this work, we present the first results with a high-resolution preclinical PET scanner based on thin monolithic scintillators and a large solid angle. The design is dedicated to rat-brain imaging and therefore has a very compact geometry. Four detectors were placed in a square arrangement with a distance of 34.5 mm between two opposing detector modules, defining a field of view (FOV) of 32 × 32 × 32 mm3. Each detector consists of a thin monolithic LYSO crystal of 32 × 32 × 2 mm3 optically coupled to a digital silicon photomultiplier (dSiPM). Event positioning within each detector was obtained using the maximum likelihood estimation (MLE) method. To evaluate the system performance, we measured the energy resolution, coincidence resolving time (CRT), sensitivity and spatial resolution. The image quality was evaluated by acquiring a hot-rod phantom filled with 18F-FDG and a rat head one hour after an 18F-FDG injection. The MLE yielded an average intrinsic spatial resolution on the detector of 0.54 mm FWHM. We obtained a CRT of 680 ps and an energy resolution of 18% FWHM at 511 keV. The sensitivity and spatial resolution obtained at the center of the FOV were 6.0 cps kBq−1 and 0.7 mm, respectively. In the reconstructed images of the hot-rod phantom, hot rods down to 0.7 mm can be discriminated. In

  2. The distribution of D2/D3 receptor binding in the adolescent rhesus monkey using small animal PET imaging

    OpenAIRE

    Christian, BT; Vandehey, NT; Fox, AS; Murali, D.; Oakes, TR; Converse, AK; Nickles, RJ; Shelton, SE; Davidson, RJ; Kalin, NH

    2008-01-01

    PET imaging of the neuroreceptor systems in the brain has earned a prominent role in studying normal development, neuropsychiatric illness and developing targeted drugs. The dopaminergic system is of particular interest due to its role in the development of cognitive function and mood as well as its suspected involvement in neuropsychiatric illness. Nonhuman primate animal models provide a valuable resource for relating neurochemical changes to behavior. To facilitate comparison within and be...

  3. Biometric Recognition for Pet Animal

    OpenAIRE

    Santosh Kumar; Sanjay Kumar Singh

    2014-01-01

    Missing, swapping, false insurance claims and reallocation of pet animals (dog) are global problems throughout the world and research done to solve this problem is minimal. Traditional biometrics and non-biometrics methods have their own boundaries and they fail to provide competent level of security to pet animal (dog). The work on animal identification based on their phenotype appearance (coat patterns) has been an active research area in recent years and automatic face recognition for...

  4. Instruments for radiation measurement in life sciences (5). ''Development of imaging technology in life sciences''. I. PET radiopharmaceuticals and animal imaging devices

    International Nuclear Information System (INIS)

    This review describes PET radiopharmaceuticals (Rp) for imaging of functions of brain and heart and of tumors as well as PET devices for animals. Nuclides in PET are positron emitters with short half-lives like 15O, 13N, 11C, 18F and 62Cu, and Rp contains the nuclide in its chemical structure. For the brain functional studies in animals and man, regional cerebral blood volume, its flow, energy metabolism, neurotransmission/receptor and others are measured with use of a Rp like, typically, 15O2 gas, H215O/123I-IMP, 15O2 gas/18F-FDG, 11C-methylspiperone and 18F-DDNP (a fluorescent dye binding to amyloids), respectively. (123I is not a positron emitter). Rp for early PET diagnosis of Alzheimer disease is awaited. For the cardiac function, energy metabolism, myocardial blood flow and nerve functions are by 18F-FDG/11C-palmitate, 13N-ammonia, and 11C-GB67 (for alpha-receptor imaging), respectively. For tumor imaging, 18F-FDG is a representative Rp and derivatives of nucleic acids, amino acids and choline are now under investigation. PET devices for experimental animals involve small machines like microPET, planar positron imaging system by Hamamatsu Photonics Co., and those for dynamic positron autoradiography of Rp uptake in the living specimen like tissue slices. PET studies in animals have a potential for the development of new drugs, physiological and pathological analyses and novel treatment of diseases as well as for clinical application. (T.I.)

  5. Attenuation correction for small animal PET tomographs

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Patrick L [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States); Rannou, Fernando R [Departamento de Ingenieria Informatica, Universidad de Santiago de Chile (USACH), Av. Ecuador 3659, Santiago (Chile); Chatziioannou, Arion F [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States)

    2005-04-21

    Attenuation correction is one of the important corrections required for quantitative positron emission tomography (PET). This work will compare the quantitative accuracy of attenuation correction using a simple global scale factor with traditional transmission-based methods acquired either with a small animal PET or a small animal x-ray computed tomography (CT) scanner. Two phantoms (one mouse-sized and one rat-sized) and two animal subjects (one mouse and one rat) were scanned in CTI Concorde Microsystem's microPET (registered) Focus{sup TM} for emission and transmission data and in ImTek's MicroCAT{sup TM} II for transmission data. PET emission image values were calibrated against a scintillation well counter. Results indicate that the scale factor method of attenuation correction places the average measured activity concentration about the expected value, without correcting for the cupping artefact from attenuation. Noise analysis in the phantom studies with the PET-based method shows that noise in the transmission data increases the noise in the corrected emission data. The CT-based method was accurate and delivered low-noise images suitable for both PET data correction and PET tracer localization.

  6. Design considerations for a C-shaped PET system, dedicated to small animal brain imaging, using GATE Monte Carlo simulations

    Science.gov (United States)

    Efthimiou, N.; Papadimitroulas, P.; Kostou, T.; Loudos, G.

    2015-09-01

    Commercial clinical and preclinical PET scanners rely on the full cylindrical geometry for whole body scans as well as for dedicated organs. In this study we propose the construction of a low cost dual-head C-shaped PET system dedicated for small animal brain imaging. Monte Carlo simulation studies were performed using GATE toolkit to evaluate the optimum design in terms of sensitivity, distortions in the FOV and spatial resolution. The PET model is based on SiPMs and BGO pixelated arrays. Four different configurations with C- angle 0°, 15°, 30° and 45° within the modules, were considered. Geometrical phantoms were used for the evaluation process. STIR software, extended by an efficient multi-threaded ray tracing technique, was used for the image reconstruction. The algorithm automatically adjusts the size of the FOV according to the shape of the detector's geometry. The results showed improvement in sensitivity of ∼15% in case of 45° C-angle compared to the 0° case. The spatial resolution was found 2 mm for 45° C-angle.

  7. Small animal PET imaging of HSV1-tk gene expression with 124IVDU in liver by the hydrodynamic injection

    International Nuclear Information System (INIS)

    The liver is an important target organ for gene transfer due to its capacity for synthesizing serum protein and its involvement in numerous genetic diseases. High level of foreign gene expression in liver can be achieved by a large-volume and high-speed intravenous injection of naked plasmid DNA (pDNA), so called hydrodynamic injection. This study is aimed to evaluate liver specific-gene expression of herpes simplex virus type 1 thymidine kinase(HSV1-tk) by hydrodynamic injection and image HSV1-tk expression using 124IVDU-PET. We constructed herpes simplex virus type 1 thymidine kinase (HSV1-tk)-expressing pDNA (pHSV1-tk) modified from pEGFP-N1. Hydrodynamic injection was performed using 40 μg of plasmid (pEGFP/N1 or pHSV1-tk) in 2 ml of 0.85% saline solution for 20∼22g mice in 5 seconds intravenously. At 1 d post-hydrodynamic injection, biodistribution study was performed at 2 h post-injection of radiolabeled IVDU, fluorescence image was obtained using optical imager and small animal PET image was acquired with 124IVDU at 2 h post-injection. After PET imaging, digital whole body autoradiography (DWBA) was performed. Expression of HSV1-tk and EGFP was confirmed by RT-PCR in each liver tissue. In liver of pHSV1-tk and pEGFP/N1 injection groups, 123IVDU uptake was 5.65%ID/g and 0.98%ID/g, respectively. 123IVDU uptake in liver of pHSV1-tk injection group showed 5.7-fold higher than that of pEGFP/N1 injection group (p124IVDU uptake was selectively localized in liver of pHSV1-tk injection group and also checked in DWBA, but showed minimal uptake in liver of pEGFP/N1 injection mice. Hydrodynamic injection was effective to liver-specific delivery of plasmid DNA. Small animal PET image of 124IVDU could be used in the evaluation of noninvasive reporter gene imaging in liver

  8. Contrast-enhanced small-animal PET/CT in cancer research: strong improvement of diagnostic accuracy without significant alteration of quantitative accuracy and NEMA NU 4–2008 image quality parameters

    OpenAIRE

    Lasnon, Charline; Quak, Elske; Briand, Mélanie; Gu, Zheng; Louis, Marie-Hélène; Aide, Nicolas

    2013-01-01

    Background The use of iodinated contrast media in small-animal positron emission tomography (PET)/computed tomography (CT) could improve anatomic referencing and tumor delineation but may introduce inaccuracies in the attenuation correction of the PET images. This study evaluated the diagnostic performance and accuracy of quantitative values in contrast-enhanced small-animal PET/CT (CEPET/CT) as compared to unenhanced small animal PET/CT (UEPET/CT). Methods Firstly, a NEMA NU 4–2008 phantom (...

  9. Optical fiber readout of scintillator arrays using a multi-channel PMT: A high resolution PET detector for animal imaging

    International Nuclear Information System (INIS)

    The authors report the results from a new high resolution gamma ray imaging detector designed for use in a positron emission tomography (PET) system dedicated to small animal imaging. The detectors consist of an 8 x 8 array of 2 x 2 x 10 mm bismuth germanate (BGO) crystals coupled by 2 mm diameter double clad optical fibers to a 64 pixel multi-channel photomultiplier tube (MC-PMT). A charge division readout board is used to convert the 64 output channels into four position sensitive signals which determine the crystal of interaction. Measurements with a pair of these detectors demonstrate an intrinsic spatial resolution of 1.4 mm, a coincidence timing resolution of 15 ns and an energy resolution ranging between 35 and 60%. Based on these encouraging results, the design for a dedicated animal PET tomograph is proposed and simulations of this system project a reconstructed resolution of less than 2 mm within a 5 cm diameter transaxial field of view

  10. The Combination of In vivo 124I-PET and CT small animal imaging for evaluation of thyroid physiology and dosimetry

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Eckerwall, Martin; Skovgaard, Dorthe Charlotte;

    2013-01-01

    Objective: A thyroid rat model combining functional and anatomical information would be of great benefit for better modeling of thyroid physiology and for absorbed dose calculations. Our aim was to show that 124I-PET and CT small animal imaging are useful as a combined model for studying thyroid...... physiology and dose calculation. Methods: Seven rats were subjects for multiple thyroid 124I-imaging and CT-scans. S-values [mGy/MBqs] for different thyroid sizes were simulated. A phantom with spheres was designed for validation of performances of the small animal PET and CT imaging systems. Results: Small...... animal PET/CT based measurements of the activity amount and the volumes of the spheres with a priori known volumes showed a good agreement with their corresponding actual volumes. The CT scans of the rats showed thyroid volumes from 34 – 70 mL. Conclusions: The wide span in volumes of thyroid glands...

  11. The Combination of In vivo 124I-PET and CT Small Animal Imaging for Evaluation of Thyroid Physiology and Dosimetry

    Directory of Open Access Journals (Sweden)

    Henrik H. El-Ali

    2012-06-01

    Full Text Available Objective: A thyroid rat model combining functional and anatomical information would be of great benefit for better modeling of thyroid physiology and for absorbed dose calculations. Our aim was to show that 124I-PET and CT small animal imaging are useful as a combined model for studying thyroid physiology and dose calculation. Methods: Seven rats were subjects for multiple thyroid 124I-imaging and CT-scans. S-values [mGy/MBqs] for different thyroid sizes were simulated. A phantom with spheres was designed for validation of performances of the small animal PET and CT imaging systems. Results: Small animal image-based measurements of the activity amount and the volumes of the spheres with a priori known volumes showed a good agreement with their corresponding actual volumes. The CT scans of the rats showed thyroid volumes from 34–70 mL. Conclusions: The wide span in volumes of thyroid glands indicates the importance of using an accurate volume-measuring technique such as the small animal CT. The small animal PET system was on the other hand able to accurately estimate the activity concentration in the thyroid volumes. We conclude that the combination of the PET and CT image information is essential for quantitative thyroid imaging and accurate thyroid absorbed dose calculation.

  12. Initial results from a PET/planar small animal imaging system

    OpenAIRE

    Siegel, Stefan; Vaquero, Juan José; Aloj, L; Seidel, Jürgen; Jagoda, E.; Gandler, William R.; Eckelman, W. C.; Green, Michael V.

    1999-01-01

    A pair of stationary, opposed scintillation detectors in time coincidence is being used to create planar projection or tomographic images of small animals injected with positronemitting radiotracers. The detectors are comprised of arrays of individual crystals of bismuth germanate coupled to position-sensitive photomultiplier tubes. The system uses FERA (LeCroy Research Systems) charge-sensitive ADCs and a low cost digital YO board as a E R A bus-to-host bridge. In pro...

  13. MicroPET II: design, development and initial performance of an improved microPET scanner for small-animal imaging

    International Nuclear Information System (INIS)

    MicroPET II is a second-generation animal PET scanner designed for high-resolution imaging of small laboratory rodents. The system consists of 90 scintillation detector modules arranged in three contiguous axial rings with a ring diameter of 16.0 cm and an axial length of 4.9 cm. Each detector module consists of a 14 x 14 array of lutetium oxyorthosilicate (LSO) crystals coupled to a multi-channel photomultiplier tube (MC-PMT) through a coherent optical fibre bundle. Each LSO crystal element measures 0.975 mm x 0.975 mm in cross section by 12.5 mm in length. A barium sulphate reflector material was used between LSO elements leading to a detector pitch of 1.15 mm in both axial and transverse directions. Fused optical fibre bundles were made from 90 μm diameter glass fibres with a numerical aperture of 0.56. Interstitial extramural absorber was added between the fibres to reduce optical cross talk. A charge-division readout circuit was implemented on printed circuit boards to decode the 196 crystals in each array from the outputs of the 64 anode signals of the MC-PMT. Electronics from Concorde Microsystems Inc. (Knoxville, TN) were used for signal amplification, digitization, event qualification, coincidence processing and data capture. Coincidence data were passed to a host PC that recorded events in list mode. Following acquisition, data were sorted into sinograms and reconstructed using Fourier rebinning and filtered backprojection algorithms. Basic evaluation of the system has been completed. The absolute sensitivity of the microPET II scanner was 2.26% at the centre of the field of view (CFOV) for an energy window of 250-750 keV and a timing window of 10 ns. The intrinsic spatial resolution of the detectors in the system averaged 1.21 mm full width at half maximum (FWHM) when measured with a 22Na point source 0.5 mm in diameter. Reconstructed image resolution ranged from 0.83 mm FWHM at the CFOV to 1.47 mm FWHM in the radial direction, 1.17 mm FWHM in the

  14. Small-animal PET imaging of the type 1 and type 2 cannabinoid receptors in a photothrombotic stroke model

    Energy Technology Data Exchange (ETDEWEB)

    Vandeputte, Caroline; Casteels, Cindy; Koole, Michel; Gerits, Anneleen [KU Leuven, Division of Nuclear Medicine, Leuven (Belgium); KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); Struys, Tom [Hasselt University, Laboratory of Histology, Biomedical Research Institute, Hasselt (Belgium); KU Leuven, Biomedical NMR Unit, Leuven (Belgium); Veghel, Daisy van; Evens, Nele; Bormans, Guy [KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); KU Leuven, Laboratory of Radiopharmacy, Leuven (Belgium); Dresselaers, Tom; Himmelreich, Uwe [KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); KU Leuven, Biomedical NMR Unit, Leuven (Belgium); Lambrichts, Ivo [Hasselt University, Laboratory of Histology, Biomedical Research Institute, Hasselt (Belgium); Laere, Koen van [KU Leuven, Division of Nuclear Medicine, Leuven (Belgium); KU Leuven, Molecular Small Animal Imaging Center, MoSAIC, Leuven (Belgium); UZ Leuven, Division of Nuclear Medicine, Leuven (Belgium)

    2012-11-15

    Recent ex vivo and pharmacological evidence suggests involvement of the endocannabinoid system in the pathophysiology of stroke, but conflicting roles for type 1 and 2 cannabinoid receptors (CB{sub 1} and CB{sub 2}) have been suggested. The purpose of this study was to evaluate CB{sub 1} and CB{sub 2} receptor binding over time in vivo in a rat photothrombotic stroke model using PET. CB{sub 1} and CB{sub 2} microPET imaging was performed at regular time-points up to 2 weeks after stroke using [{sup 18}F]MK-9470 and [{sup 11}C]NE40. Stroke size was measured using MRI at 9.4 T. Ex vivo validation was performed via immunostaining for CB{sub 1} and CB{sub 2}. Immunofluorescent double stainings were also performed with markers for astrocytes (GFAP) and macrophages/microglia (CD68). [{sup 18}F]MK-9470 PET showed a strong increase in CB{sub 1} binding 24 h and 72 h after stroke in the cortex surrounding the lesion, extending to the insular cortex 24 h after surgery. These alterations were consistently confirmed by CB{sub 1} immunohistochemical staining. [{sup 11}C]NE40 did not show any significant differences between stroke and sham-operated animals, although staining for CB{sub 2} revealed minor immunoreactivity at 1 and 2 weeks after stroke in this model. Both CB{sub 1} {sup +} and CB{sub 2} {sup +} cells showed minor immunoreactivity for CD68. Time-dependent and regionally strongly increased CB{sub 1}, but not CB{sub 2}, binding are early consequences of photothrombotic stroke. Pharmacological interventions should primarily aim at CB{sub 1} signalling as the role of CB{sub 2} seems minor in the acute and subacute phases of stroke. (orig.)

  15. Small-animal PET imaging of the type 1 and type 2 cannabinoid receptors in a photothrombotic stroke model

    International Nuclear Information System (INIS)

    Recent ex vivo and pharmacological evidence suggests involvement of the endocannabinoid system in the pathophysiology of stroke, but conflicting roles for type 1 and 2 cannabinoid receptors (CB1 and CB2) have been suggested. The purpose of this study was to evaluate CB1 and CB2 receptor binding over time in vivo in a rat photothrombotic stroke model using PET. CB1 and CB2 microPET imaging was performed at regular time-points up to 2 weeks after stroke using [18F]MK-9470 and [11C]NE40. Stroke size was measured using MRI at 9.4 T. Ex vivo validation was performed via immunostaining for CB1 and CB2. Immunofluorescent double stainings were also performed with markers for astrocytes (GFAP) and macrophages/microglia (CD68). [18F]MK-9470 PET showed a strong increase in CB1 binding 24 h and 72 h after stroke in the cortex surrounding the lesion, extending to the insular cortex 24 h after surgery. These alterations were consistently confirmed by CB1 immunohistochemical staining. [11C]NE40 did not show any significant differences between stroke and sham-operated animals, although staining for CB2 revealed minor immunoreactivity at 1 and 2 weeks after stroke in this model. Both CB1+ and CB2+ cells showed minor immunoreactivity for CD68. Time-dependent and regionally strongly increased CB1, but not CB2, binding are early consequences of photothrombotic stroke. Pharmacological interventions should primarily aim at CB1 signalling as the role of CB2 seems minor in the acute and subacute phases of stroke. (orig.)

  16. I-124 labeled recombinant human annexin V produced by E. coli for apoptosis image using small animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J. H.; Lee, I. S.; Woo, S. K.; Woo, G. S.; Chung, W. S.; Kang, J. H.; Cheon, G. J.; Choi, C. W.; Urn, S. M. [Korea Institute of Radiological and Medical Sciences, Daejeon (Korea, Republic of)

    2007-07-01

    Annexin V labeled with radioisotope and optical probe has been used to detect apoptosis. To evaluate annexin V as a multimodal apoptosis imaging agent, large-scale preparation of Annexin V (AV) is preliminary. The aim of this study is to produce and purify recombinant human Annexin V (rh-AV) in E. coli system and radiolabeled rh-AV evaluate in vitro and in vivo apoptosis model system. Annexin V cDNA was obtained from human placenta and rh-AV cloning vector used fusion E. coli vector. Expression vector was based on the E. coli pET system. Induction of rh-AV was used Isopropyl--D-thiogalactoside (IPTG) and purification was used TALON metal affinity resin and T7 - Taq. Purification yield confirmed through SDS-PAGE. In camptothecin (0, 50, 100 uM) induced Jurkat T cell apoptosis model, AV-PI flow cytometry analysis and in vitro binding assay of I-124 labeled rh - AV were performed and compared. Small animal PET images of I-124 labeled rh-AV were obtained in Fas-mediated hepatic apoptosis model. Optimum expression condition was at 37, 250 rpm, 8 hr in 2X YT media including 1mM IPTG, Through two step purification process, rh-AV confirmed about 35 Kd single band by SDS-PAGE. As camptothecin concentration increasing, annexin V-FITC positive % increased in flow cytometry analysis and uptake of I-124 labeled rh-AV also increased. Annexin V-FITC positive % was correlated with and uptake of I-124 labeled rh-AV (R{sup 2}=0.99). In Fas-mediated hepatic apoptosis model, I-124 labeled rh-AV was selectively localized in liver region in PET image. Recombinant Human annexin V was produced by E. coli system and purified using two step affinity chromatography. Radiolabeled rh-AV was useful for the evaluation of apoptosis in vitro and in vivo model. Recombinant human annexin V could be used as apoptosis imaging agent with various radiolabel and optical probe.

  17. I-124 labeled recombinant human annexin V produced by E. coli for apoptosis image using small animal PET

    International Nuclear Information System (INIS)

    Annexin V labeled with radioisotope and optical probe has been used to detect apoptosis. To evaluate annexin V as a multimodal apoptosis imaging agent, large-scale preparation of Annexin V (AV) is preliminary. The aim of this study is to produce and purify recombinant human Annexin V (rh-AV) in E. coli system and radiolabeled rh-AV evaluate in vitro and in vivo apoptosis model system. Annexin V cDNA was obtained from human placenta and rh-AV cloning vector used fusion E. coli vector. Expression vector was based on the E. coli pET system. Induction of rh-AV was used Isopropyl--D-thiogalactoside (IPTG) and purification was used TALON metal affinity resin and T7 - Taq. Purification yield confirmed through SDS-PAGE. In camptothecin (0, 50, 100 uM) induced Jurkat T cell apoptosis model, AV-PI flow cytometry analysis and in vitro binding assay of I-124 labeled rh - AV were performed and compared. Small animal PET images of I-124 labeled rh-AV were obtained in Fas-mediated hepatic apoptosis model. Optimum expression condition was at 37, 250 rpm, 8 hr in 2X YT media including 1mM IPTG, Through two step purification process, rh-AV confirmed about 35 Kd single band by SDS-PAGE. As camptothecin concentration increasing, annexin V-FITC positive % increased in flow cytometry analysis and uptake of I-124 labeled rh-AV also increased. Annexin V-FITC positive % was correlated with and uptake of I-124 labeled rh-AV (R2=0.99). In Fas-mediated hepatic apoptosis model, I-124 labeled rh-AV was selectively localized in liver region in PET image. Recombinant Human annexin V was produced by E. coli system and purified using two step affinity chromatography. Radiolabeled rh-AV was useful for the evaluation of apoptosis in vitro and in vivo model. Recombinant human annexin V could be used as apoptosis imaging agent with various radiolabel and optical probe

  18. Non-invasive imaging of acute renal allograft rejection in rats using small animal F-FDG-PET.

    Directory of Open Access Journals (Sweden)

    Stefan Reuter

    Full Text Available BACKGROUND: At present, renal grafts are the most common solid organ transplants world-wide. Given the importance of renal transplantation and the limitation of available donor kidneys, detailed analysis of factors that affect transplant survival are important. Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection (AR is still a major risk for graft survival. Nowadays, AR can only be definitively by renal biopsy. However, biopsies carry a risk of renal transplant injury and loss. Most important, they can not be performed in patients taking anticoagulant drugs. METHODOLOGY/PRINCIPAL FINDINGS: We present a non-invasive, entirely image-based method to assess AR in an allogeneic rat renal transplantation model using small animal positron emission tomography (PET and (18F-fluorodeoxyglucose (FDG. 3 h after i.v. injection of 30 MBq FDG into adult uni-nephrectomized, allogeneically transplanted rats, tissue radioactivity of renal parenchyma was assessed in vivo by a small animal PET-scanner (post operative day (POD 1,2,4, and 7 and post mortem dissection. The mean radioactivity (cps/mm(3 tissue as well as the percent injected dose (%ID was compared between graft and native reference kidney. Results were confirmed by histological and autoradiographic analysis. Healthy rats, rats with acute CSA nephrotoxicity, with acute tubular necrosis, and syngeneically transplanted rats served as controls. FDG-uptake was significantly elevated only in allogeneic grafts from POD 1 on when compared to the native kidney (%ID graft POD 1: 0.54+/-0.06; POD 2: 0.58+/-0.12; POD 4: 0.81+/-0.06; POD 7: 0.77+/-0.1; CTR: 0.22+/-0.01, n = 3-28. Renal FDG-uptake in vivo correlated with the results obtained by micro-autoradiography and the degree of inflammatory infiltrates observed in histology. CONCLUSIONS/SIGNIFICANCE: We propose that graft FDG-PET imaging is a new option to non-invasively, specifically, early detect, and follow

  19. Small-Animal PET Imaging of Amyloid-Beta Plaques with [11C]PiB and Its Multi-Modal Validation in an APP/PS1 Mouse Model of Alzheimer's Disease

    OpenAIRE

    Manook, André; Yousefi, Behrooz H.; Willuweit, Antje; Platzer, Stefan; Reder, Sybille; Voss, Andreas; Huisman, Marc; Settles, Markus; Neff, Frauke; Velden, Joachim; Schoor, Michael; von der Kammer, Heinz; Wester, Hans-Jürgen; Schwaiger, Markus; Henriksen, Gjermund

    2012-01-01

    In vivo imaging and quantification of amyloid-β plaque (Aβ) burden in small-animal models of Alzheimer's disease (AD) is a valuable tool for translational research such as developing specific imaging markers and monitoring new therapy approaches. Methodological constraints such as image resolution of positron emission tomography (PET) and lack of suitable AD models have limited the feasibility of PET in mice. In this study, we evaluated a feasible protocol for PET imaging of Aβ in mouse brain...

  20. Demonstration of an Axial PET concept for brain and small animal imaging

    CERN Document Server

    Beltrame, P; Clinthorne, N; Meddi, F; Kagan, H; Braem, A; Pauss, F; Djambazov, L; Lustermann, W; Weilhammer, P; Nessi-Tedaldi, F; Dissertori, G; Renker, D; Schneider, T; Schinzel, D; De Leo, R; Bolle, E; Fanti, V; Rafecas, M; Rudge, A; Stapnes, S; Casella, C; Chesi, E; Seguinot, J; Solevi, P; Joram, C; Oliver, J F

    2011-01-01

    Standard Positron Emission Tomography (PET) cameras need to reach a compromise between spatial resolution and sensitivity. To overcome this limitation we developed a novel concept of PET. Our AX-PET demonstrator is made of LYSO crystals aligned along the z coordinate (patient's axis) and WLS strips orthogonally placed with respect to the crystals. This concept offers full 3D localization of the photon interaction inside the camera. Thus the spatial resolution and the sensitivity can be simultaneously improved and the reconstruction of Compton interactions inside the detector is also possible. Moreover, by means of G-APDs for reading out the photons, both from LYSO and WLS, the detector is insensitive to magnetic fields and it is then suitable to be used in a combined PET/MRI apparatus. A complete Monte Carlo simulation and dedicated reconstruction software have been developed. The two final modules, each composed of 48 crystals and 156 WLS strips, have been built and fully characterized in a dedicated test se...

  1. A Very High Spatial Resolution Detector for Small Animal PET

    International Nuclear Information System (INIS)

    Positron Emission Tomography (PET) is an in vivo analog of autoradiography and has the potential to become a powerful new tool in imaging biological processes in small laboratory animals. PET imaging of small animals can provide unique information that can help in advancement of human disease models as well as drug development. Clinical PET scanners used for human imaging are bulky, expensive and do not have adequate spatial resolution for small animal studies. Hence, dedicated, low cost instruments are required for conducting small animal studies with higher spatial resolution than what is currently achieved with clinical as well as dedicated small animal PET scanners. The goal of the proposed project is to investigate a new all solid-state detector design for small animal PET imaging. Exceptionally high spatial resolution, good timing resolution, and excellent energy resolution are expected from the proposed detector design. The Phase I project was aimed at demonstrating the feasibility of producing high performance solid-state detectors that provide high sensitivity, spatial resolution, and timing characteristics. Energy resolution characteristics of the new detector were also investigated. The goal of the Phase II project is to advance the promising solid-state detector technology for small animal PET and determine its full potential. Detectors modules will be built and characterized and finally, a bench-top small animal PET system will be assembled and evaluated

  2. Studies oriented to optimize the image quality of the small animal PET: Clear PET, modifying some of the parameters of the reconstruction algorithm IMF-OSEM 3D on the data acquisition simulated with GAMOS

    International Nuclear Information System (INIS)

    This report presents studies oriented to optimize the image quality of the small animal PET: Clear- PET. Certain figures of merit (FOM) were used to assess a quantitative value of the contrast and delectability of lesions. The optimization was carried out modifying some of the parameters in the reconstruction software of the scanner, imaging a mini-Derenzo phantom and a cylinder phantom with background activity and two hot spheres. Specifically, it was evaluated the incidence of the inter-update Metz filter (IMF) inside the iterative reconstruction algorithm 3D OSEM. The data acquisition was simulated using the GAMOS framework (Monte Carlo simulation). Integrating GAMOS output with the reconstruction software of the scanner was an additional novelty of this work, to achieve this, data sets were written with the list-mode format (LMF) of ClearPET. In order to verify the optimum values obtained, we foresee to make real acquisitions in the ClearPET of CIEMAT. (Author) 17 refs

  3. A new animal model for the imaging of melanoma: correlation of FDG PET with clinical outcome, macroscopic aspect and histological classification in Melanoblastoma-bearing Libechov Minipigs

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the Melanoblastoma-bearing Libechov Minipigs (MeLiM) as an animal model of melanoma for in vivo imaging. Serial whole-body 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG PET) scans were conducted on five MeLiM. In order to explore different clinical stages of the tumoural lesions, each animal was scanned two to four times, at intervals of 30-155 days. PET images were analysed by a semiquantitative method based on the tumour to muscle metabolic ratio. Histology was performed on biopsies taken between or after the scans and the histological grading of the tumours was compared with the FDG uptake. The overall sensitivity of FDG PET for the detection of cutaneous melanoma was 75%; 62.5% of involved lymph nodes were positive. Sensitivity was better for tumours with vertical growth than for flat lesions. FDG PET did not detect tumours with epidermal involvement only, nor did it detect small metastatic foci. The metabolic ratio was correlated with the evolution of the melanoma. FDG PET is effective in the staging of cutaneous melanoma and the follow-up of tumoural extension and regression in Melanoblastoma-bearing Libechov Minipigs. The results obtained in this animal model correlate well with those described in human melanoma. Accordingly, this model may be useful in testing new tracers specific for melanoma and in helping to detect molecules expressed early during tumoural regression. (orig.)

  4. Small-Animal PET Imaging of Tau Pathology with 18F-THK5117 in 2 Transgenic Mouse Models.

    Science.gov (United States)

    Brendel, Matthias; Jaworska, Anna; Probst, Federico; Overhoff, Felix; Korzhova, Viktoria; Lindner, Simon; Carlsen, Janette; Bartenstein, Peter; Harada, Ryuichi; Kudo, Yukitsuka; Haass, Christian; Van Leuven, Fred; Okamura, Nobuyuki; Herms, Jochen; Rominger, Axel

    2016-05-01

    Abnormal accumulation of tau aggregates in the brain is one of the hallmarks of Alzheimer disease neuropathology. We visualized tau deposition in vivo with the previously developed 2-arylquinoline derivative (18)F-THK5117 using small-animal PET in conjunction with autoradiography and immunohistochemistry gold standard assessment in 2 transgenic mouse models expressing hyperphosphorylated tau. Small-animal PET recordings were obtained in groups of P301S (n = 11) and biGT mice (n = 16) of different ages, with age-matched wild-type (WT) serving as controls. After intravenous administration of 16 ± 2 MBq of (18)F-THK5117, a dynamic 90-min emission recording was initiated for P301S mice and during 20-50 min after injection for biGT mice, followed by a 15-min transmission scan. After coregistration to the MRI atlas and scaling to the cerebellum, we performed volume-of-interest-based analysis (SUV ratio [SUVR]) and statistical parametric mapping. Small-animal PET results were compared with autoradiography ex vivo and in vitro and further validated with AT8 staining for neurofibrillary tangles. SUVRs calculated from static recordings during the interval of 20-50 min after tracer injection correlated highly with estimates of binding potential based on the entire dynamic emission recordings (R = 0.85). SUVR increases were detected in the brain stem of aged P301S mice (+11%; P parametric mapping analysis. Saturable binding of the tracer was verified by autoradiographic blocking studies. In the first dedicated small-animal PET study in 2 different transgenic tauopathy mouse models using the tau tracer (18)F-THK5117, the temporal and spatial progression could be visualized in good correlation with gold standard assessments of tau accumulation. The serial small-animal PET method could afford the means for preclinical testing of novel therapeutic approaches by accommodating interanimal variability at baseline, while detection thresholds in young animals have to be considered

  5. Small animal PET imaging of TAG-72 expressing tumor using 68Ga-NOTA-3E8 Fab radioimmunoconjugate

    International Nuclear Information System (INIS)

    The tumor-associated glycoprotein TAG-72 is express ed in the majority of human adenocarcinomas but is rarely expressed in most normal tissues, which makes it a potential target for the diagnosis and therapy of a variety of human cancer. 3E8 is anti-TAG-72 humanized antibody. Antibody fragments have some advantages such as improved pharmacokinetics and reduced immunogenicity compared to whole IgG. 68Ga is a short-lived positron emitter (t1/268 min; β+, 88%) that is produced, independent from a cyclotron, by a 68Ge/68Ga generator. The parent nuclide 68Ge has a long half-life (270.8 day), allowing its use as a generator for more than 1 year. A 68Ga is labeled with antibodies through bifunctional chelators, which allows possible kit formulation and which wide availability of the nuclear imaging agents. In this study, Fab fragment of anti-TAG-72 humanized Ab (3E8) was conjugated with 2-(p-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4, 7-triacetic acid (p-SCN-Bn-NOTA) and radiolabeled with 68Ga and acquire small animal PET image

  6. PET imaging of inflammation

    International Nuclear Information System (INIS)

    Inflammatory diseases are common place and often chronic. Most inflammatory cells have increased uptake of glucose which is enhanced in the presence of local cytokines. Therefore, imaging glucose metabolism by the means of 18F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET) holds significant promise in imaging focal inflammation. Most of the work published involved small series of patients with either vasculitis, sarcoid or rheumatoid arthritis. It would appear that FDG PET is a simple and effective technique to identify inflammatory tissue in these conditions. There is even some work to suggest that by comparing baseline and early post therapy scans clinical outcome can be predicted. This would appear to be true with vasculitis as well as retroperitoneal fibrosis. The number of patients in each study is small but the evidence is compelling enough to recommend FDG PET imaging in the routine care of these patients.

  7. Characteristics of a multichannel low-noise front-end ASIC for CZT-based small animal PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gao, W., E-mail: gaowu@nwpu.edu.cn [Institute of Microelectronics, School of Computer S and T, Northwestern Polytechnical University, Xi’an (China); Liu, H., E-mail: newhui.cn@gmail.com [Institute of Microelectronics, School of Computer S and T, Northwestern Polytechnical University, Xi’an (China); Gan, B., E-mail: shadow524@163.com [Institute of Microelectronics, School of Computer S and T, Northwestern Polytechnical University, Xi’an (China); Hu, Y., E-mail: Yann.Hu@ires.in2p3.fr [Institut Pluridisciplinaire Hubert Curien, IN2P3/CNRS/UDS, Strasbourg (France)

    2014-05-01

    In this paper, we present the design and characteristics of a novel low-noise front-end readout application-specific integrated circuit dedicated to CdZnTe (CZT) detectors for a small animal PET imaging system. A low-noise readout method based on the charge integration and the delayed peak detection is proposed. An eight-channel front-end readout prototype chip is designed and implemented in a 0.35 μm CMOS process. The die size is 2.3 mm ×2.3 mm. The prototype chip is tested in different methods including electronic test, energy spectrum test and irradiation test. The input range of the ASIC is from 2000e{sup −} to 180,000e{sup −}, reflecting the energy of the gamma ray from 11.2 keV to 1 MeV. The gain of the readout channel is 65 mV/fC at the shaping time of 1 μs. The best test result of the equivalent noise charge (ENC) is 58.9 e{sup −} at zero farad plus 5.4 e{sup −} per picofarad. The nonlinearity and the crosstalk are less than 3% and less than 2%, respectively, at the room temperature. The static power dissipation is about 3 mW/channel.

  8. Comparison of 3D Maximum A Posteriori and Filtered Backprojection algorithms for high resolution animal imaging in microPET

    Energy Technology Data Exchange (ETDEWEB)

    Chatziioannou, A.; Qi, J.; Moore, A.; Annala, A.; Nguyen, K.; Leahy, R.M.; Cherry, S.R.

    2000-01-01

    We have evaluated the performance of two three dimensional reconstruction algorithms with data acquired from microPET, a high resolution tomograph dedicated to small animal imaging. The first was a linear filtered-backprojection algorithm (FBP) with reprojection of the missing data and the second was a statistical maximum-aposteriori probability algorithm (MAP). The two algorithms were evaluated in terms of their resolution performance, both in phantoms and in vivo. Sixty independent realizations of a phantom simulating the brain of a baby monkey were acquired, each containing 3 million counts. Each of these realizations was reconstructed independently with both algorithms. The ensemble of the sixty reconstructed realizations was used to estimate the standard deviation as a measure of the noise for each reconstruction algorithm. More detail was recovered in the MAP reconstruction without an increase in noise relative to FBP. Studies in a simple cylindrical compartment phantom demonstrated improved recovery of known activity ratios with MAP. Finally in vivo studies also demonstrated a clear improvement in spatial resolution using the MAP algorithm. The quantitative accuracy of the MAP reconstruction was also evaluated by comparison with autoradiography and direct well counting of tissue samples and was shown to be superior.

  9. Comparison of 3D Maximum A Posteriori and Filtered Backprojection algorithms for high resolution animal imaging in microPET

    International Nuclear Information System (INIS)

    We have evaluated the performance of two three dimensional reconstruction algorithms with data acquired from microPET, a high resolution tomograph dedicated to small animal imaging. The first was a linear filtered-backprojection algorithm (FBP) with reprojection of the missing data and the second was a statistical maximum-aposteriori probability algorithm (MAP). The two algorithms were evaluated in terms of their resolution performance, both in phantoms and in vivo. Sixty independent realizations of a phantom simulating the brain of a baby monkey were acquired, each containing 3 million counts. Each of these realizations was reconstructed independently with both algorithms. The ensemble of the sixty reconstructed realizations was used to estimate the standard deviation as a measure of the noise for each reconstruction algorithm. More detail was recovered in the MAP reconstruction without an increase in noise relative to FBP. Studies in a simple cylindrical compartment phantom demonstrated improved recovery of known activity ratios with MAP. Finally in vivo studies also demonstrated a clear improvement in spatial resolution using the MAP algorithm. The quantitative accuracy of the MAP reconstruction was also evaluated by comparison with autoradiography and direct well counting of tissue samples and was shown to be superior

  10. Characteristics of a multichannel low-noise front-end ASIC for CZT-based small animal PET imaging

    Science.gov (United States)

    Gao, W.; Liu, H.; Gan, B.; Hu, Y.

    2014-05-01

    In this paper, we present the design and characteristics of a novel low-noise front-end readout application-specific integrated circuit dedicated to CdZnTe (CZT) detectors for a small animal PET imaging system. A low-noise readout method based on the charge integration and the delayed peak detection is proposed. An eight-channel front-end readout prototype chip is designed and implemented in a 0.35 μm CMOS process. The die size is 2.3 mm ×2.3 mm. The prototype chip is tested in different methods including electronic test, energy spectrum test and irradiation test. The input range of the ASIC is from 2000e- to 180,000e-, reflecting the energy of the gamma ray from 11.2 keV to 1 MeV. The gain of the readout channel is 65 mV/fC at the shaping time of 1 μs. The best test result of the equivalent noise charge (ENC) is 58.9 e- at zero farad plus 5.4 e- per picofarad. The nonlinearity and the crosstalk are less than 3% and less than 2%, respectively, at the room temperature. The static power dissipation is about 3 mW/channel.

  11. Characteristics of a multichannel low-noise front-end ASIC for CZT-based small animal PET imaging

    International Nuclear Information System (INIS)

    In this paper, we present the design and characteristics of a novel low-noise front-end readout application-specific integrated circuit dedicated to CdZnTe (CZT) detectors for a small animal PET imaging system. A low-noise readout method based on the charge integration and the delayed peak detection is proposed. An eight-channel front-end readout prototype chip is designed and implemented in a 0.35 μm CMOS process. The die size is 2.3 mm ×2.3 mm. The prototype chip is tested in different methods including electronic test, energy spectrum test and irradiation test. The input range of the ASIC is from 2000e− to 180,000e−, reflecting the energy of the gamma ray from 11.2 keV to 1 MeV. The gain of the readout channel is 65 mV/fC at the shaping time of 1 μs. The best test result of the equivalent noise charge (ENC) is 58.9 e− at zero farad plus 5.4 e− per picofarad. The nonlinearity and the crosstalk are less than 3% and less than 2%, respectively, at the room temperature. The static power dissipation is about 3 mW/channel

  12. PET imaging of hypoxia

    International Nuclear Information System (INIS)

    Hypoxia in tumors has been related to poor response to conventional therapies. This paper will discuss the methods, both invasive and non-invasive, used to determine hypoxia levels within tumors. PET imaging with two lead compounds 18F-fluoro misonidazole (18FMISO) and Cu-(II)-diacetyl-bis(N4-methylthiosemicarbazone (Cu-ATSM) and their relative effectiveness in delineating hypoxic regions will be discussed. The advantages of Cu-ATSM-PET over existing imaging agents will be discussed along with its potential application as a direct-and/or surrogate marker for the determination of oncological hypoxia in vivo

  13. In vivo imaging of microglial activation using a peripheral benzodiazepine receptor ligand. [11C]PK-11195 and animal PET following ethanol injury in rat striatum

    International Nuclear Information System (INIS)

    To investigate whether [11C]PK-11195, a specific peripheral benzodiazepine receptors (PBRs) ligand for positron emission tomography (PET), can show activated microglia in a rat brain injury model. On day 1, ethanol was injected into the rat's right striatum (ST) using a stereotaxic operative procedure. On day 3, head magnetic resonance imaging (MRI) scans for surgically treated rats were performed to evaluate ethanol injury morphologically. On day 4, dynamic PET scans (17 injured rats and 7 non-injured controls) were performed for 60 min with an animal PET scanner under chloral hydrate anesthesia following a bolus injection of [11C]PK-11195 through tail vein. Because PBRs are present throughout the brain, there is no suitable receptor-free reference region. The reference tissue model may not be applicable because of low target to back-ground ratio for low affinity of [11C]PK-11195 to PBRs. We evaluated the PBRs binding with regions of interest (ROIs)-based approach to estimate total distribution volume (V). We used an integral from 0 min to 60 min (V60) as an estimate of V. On the coronal PET image, ROIs were placed on bilateral ST. Differences in right/left ST V60 ratios between lesioned and unlesioned control rats were compared using unpaired t tests. Immunohistochemical staining was performed for confirming the presence of activated microglia following decapitation on the PET experiment day. The right/left ST V60 ratios in lesioned rats (1.07±0.08) were significantly higher than those in unlesioned control rats (1.00±0.06, P11C]PK-11195 PET imaging would be a useful tool for evaluating microglial activation in a rat brain injury model. (author)

  14. The influence of the image reconstruction in relative quantification in SPECT/PET/CT animal; A influencia da reconstrucao da imagem na quantificacao relativa em SPECT/PET/CT animal

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, Sarah; Sa, Lidia Vasconcellos de, E-mail: sarahsoriano@bolsista.ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ),Rio de Janeiro, RJ (Brazil); Souza, Sergio; Barboza, Thiago [Hospital Universitario Clementino Fraga Filho (HUCFF/UFRJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    The objective of this study is to evaluate the spatial resolution of the equipment SPECT/PET/CT animal to different reconstruction methods and the influence of this parameter in the mouse dosimetry C57BL6, aimed at development of new radiopharmaceuticals for use in humans. CT and SPECT images were obtained from a simulator composed of four spheres of different diameters (d), which simulate captating lesions by the equipment FLEX ™ Triumph ™ Pre-Clinical Imaging System used for preclinical studies in the Hospital Universitario (HU/UFRJ). In order to simulate a real study, the total volume of the simulator (body) was filled with a solution of {sup 99m}Tc diluted in water and the spheres were filled with concentrations four time higher than the body of the simulator. From the gross SPECT images it was used filtered backprojection method (FBP) with application of different filters: Hamming, Hann and Ramp, ranging the cutoff frequencies. The resolution of the equipment found in the study was 9.3 to 9.4 mm, very below the value provided by the manufacturer of 1.6mm. Thus, the protocol for mice can be optimized as being the FBP reconstruction method of Hamming filter, cutoff of 0.5 to yield a resolution from 9.3 to 9.4mm. This value indicates that captating regions of diameter below 9.3 mm are not properly quantified.

  15. Can hypoxia-PET map hypoxic cell density heterogeneity accurately in an animal tumor model at a clinically obtainable image contrast?

    International Nuclear Information System (INIS)

    Background: PET allows non-invasive mapping of tumor hypoxia, but the combination of low resolution, slow tracer adduct-formation and slow clearance of unbound tracer remains problematic. Using a murine tumor with a hypoxic fraction within the clinical range and a tracer post-injection sampling time that results in clinically obtainable tumor-to-reference tissue activity ratios, we have analyzed to what extent inherent limitations actually compromise the validity of PET-generated hypoxia maps. Materials and methods: Mice bearing SCCVII tumors were injected with the PET hypoxia-marker fluoroazomycin arabinoside (FAZA), and the immunologically detectable hypoxia marker, pimonidazole. Tumors and reference tissue (muscle, blood) were harvested 0.5, 2 and 4 h after FAZA administration. Tumors were analyzed for global (well counter) and regional (autoradiography) tracer distribution and compared to pimonidazole as visualized using immunofluorescence microscopy. Results: Hypoxic fraction as measured by pimonidazole staining ranged from 0.09 to 0.32. FAZA tumor to reference tissue ratios were close to unity 0.5 h post-injection but reached values of 2 and 6 when tracer distribution time was prolonged to 2 and 4 h, respectively. A fine-scale pixel-by-pixel comparison of autoradiograms and immunofluorescence images revealed a clear spatial link between FAZA and pimonidazole-adduct signal intensities at 2 h and later. Furthermore, when using a pixel size that mimics the resolution in PET, an excellent correlation between pixel FAZA mean intensity and density of hypoxic cells was observed already at 2 h post-injection. Conclusions: Despite inherent weaknesses, PET-hypoxia imaging is able to generate quantitative tumor maps that accurately reflect the underlying microscopic reality (i.e., hypoxic cell density) in an animal model with a clinical realistic image contrast.

  16. Simultaneous PET and MR imaging

    International Nuclear Information System (INIS)

    We have developed a prototype PET detector which is compatible with a clinical MRI system to provide simultaneous PET and MR imaging. This single-slice PET system consists of 48 2x2x10mm3 LSO crystals in a 38 mm diameter ring configuration that can be placed inside the receiver coil of the MRI system, coupled to three multi-channel photomultipliers housed outside the main magnetic field via 4 m long and 2 mm diameter optical fibres. The PET system exhibits 2 mm spatial resolution, 41% energy resolution at 511 keV and 20 ns timing resolution. Simultaneous PET and MR phantom images were successfully acquired. (author)

  17. PET-based geometrical calibration of a pinhole SPECT add-on for an animal PET scanner

    International Nuclear Information System (INIS)

    We developed SPECT imaging capability on an animal PET scanner to provide a cost effective option for animal SPECT imaging. The SPECT add-on sub-system was enabled by mechanically integrating a multiple-pinhole collimator in the PET detector ring. This study introduces a method to calibrate the geometrical parameters of the SPECT add-on using the PET imaging capability of the scanner. The proposed PET imaging-based calibration method consists of two steps: (1) paint the pinhole apertures of the collimator with a positron emitting radioactive solution; and (2) image the collimator inside the scanner in PET mode. The geometrical parameters of the multi-pinhole SPECT add-on can then be derived directly from a set of PET images by simple linear calculation and used in defining the SPECT system. The method was compared to our implementation of a SPECT calibration approach with model-based fitting of SPECT projection data. The procedure for carrying out the PET imaging-based calibration method is simpler and faster than that of our implementation of the SPECT model-based calibration method. Since it does not require model fitting, the uniqueness of the calibration result is warranted. Better quality SPECT images were reconstructed using the PET-derived calibration parameters rather than our implementation of the SPECT model-based calibration parameters. We conclude that the proposed PET imaging-based calibration method provides a highly effective means for enabling SPECT imaging on a PET scanner. (paper)

  18. PET radiopharmaceuticals for neuroreceptor imaging

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Routine clinical PET radiopharmaceuticals for the noninvasive imaging of brain receptors, transporters,and enzymes are commonly labeled with positron emitting nuclides such as carbon-11 or fluorine-18. Certain minimal conditions need to be fulfilled for these PET ligands to be used as imaging agents in vivo. Some of these prerequisites are discussed and examples of the most useful clinical PET radiopharmaceuticals that have found application in the central nervous system are reviewed.

  19. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies.

    Science.gov (United States)

    Xiong, Guoming; Paul, Cumming; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [(18)F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach. PMID:23160517

  20. PET-based molecular imaging in neuroscience

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) allows non-invasive assessment of physiological, metabolic and molecular processes in humans and animals in vivo. Advances in detector technology have led to a considerable improvement in the spatial resolution of PET (1-2 mm), enabling for the first time investigations in small experimental animals such as mice. With the developments in radiochemistry and tracer technology, a variety of endogenously expressed and exogenously introduced genes can be analysed by PET. This opens up the exciting and rapidly evolving field of molecular imaging, aiming at the non-invasive localisation of a biological process of interest in normal and diseased cells in animal models and humans in vivo. The main and most intriguing advantage of molecular imaging is the kinetic analysis of a given molecular event in the same experimental subject over time. This will allow non-invasive characterisation and ''phenotyping'' of animal models of human disease at various disease stages, under certain pathophysiological stimuli and after therapeutic intervention. The potential broad applications of imaging molecular events in vivo lie in the study of cell biology, biochemistry, gene/protein function and regulation, signal transduction, transcriptional regulation and characterisation of transgenic animals. Most importantly, molecular imaging will have great implications for the identification of potential molecular therapeutic targets, in the development of new treatment strategies, and in their successful implementation into clinical application. Here, the potential impact of molecular imaging by PET in applications in neuroscience research with a special focus on neurodegeneration and neuro-oncology is reviewed. (orig.)

  1. Cold wall effect eliminating method to determine the contrast recovery coefficient for small animal PET scanners using the NEMA NU-4 image quality phantom

    Science.gov (United States)

    Lajtos, Imre; Czernin, Johannes; Dahlbom, Magnus; Daver, Freddie; Emri, Miklos; Farshchi-Heydari, Salman; Forgacs, Attila; Hoh, Carl K.; Joszai, Istvan; Krizsan, Aron K.; Lantos, Judit; Major, Peter; Molnar, Jozsef; Opposits, Gabor; Tron, Lajos; Vera, David R.; Balkay, Laszlo

    2014-06-01

    The contrast recovery coefficients (CRC) were evaluated for five different small animal PET scanners: GE Explore Vista, Genisys4, MiniPET-2, nanoScan PC and Siemens Inveon. The NEMA NU-4 2008 performance test with the suggested image quality phantom (NU4IQ) does not allow the determination of the CRC values for the hot regions in the phantom. This drawback of NU4IQ phantom motivated us to develop a new method for this purpose. The method includes special acquisition and reconstruction protocols using the original phantom, and results in an artificially merged image enabling the evaluation of CRC values. An advantageous feature of this method is that it stops the cold wall effect from distorting the CRC calculation. Our suggested protocol results in a set of CRC values contributing to the characterization of small animal PET scanners. GATE simulations were also performed to validate the new method and verify the evaluated CRC values. We also demonstrated that the numerical values of this parameter depend on the actual object contrast of the hot region(s) and this mainly comes from the spillover effect. This effect was also studied while analysing the background activity level around the hot rods. We revealed that the calculated background mean values depended on the target contrast in a scanner specific manner. Performing the artificially merged imaging procedure and additional simulations using the micro hollow sphere (MHS) phantom geometry, we also proved that the inactive wall around the hot spheres can have a remarkable impact on the calculated CRC. In conclusion, we have shown that the proposed artificial merging procedure and the commonly used NU4IQ phantom prescribed by the NEMA NU-4 can easily deliver reliable CRC data otherwise unavailable for the NU4IQ phantom in the conventional protocol or the MHS phantom.

  2. Cold wall effect eliminating method to determine the contrast recovery coefficient for small animal PET scanners using the NEMA NU-4 image quality phantom

    International Nuclear Information System (INIS)

    The contrast recovery coefficients (CRC) were evaluated for five different small animal PET scanners: GE Explore Vista, Genisys4, MiniPET-2, nanoScan PC and Siemens Inveon. The NEMA NU-4 2008 performance test with the suggested image quality phantom (NU4IQ) does not allow the determination of the CRC values for the hot regions in the phantom. This drawback of NU4IQ phantom motivated us to develop a new method for this purpose. The method includes special acquisition and reconstruction protocols using the original phantom, and results in an artificially merged image enabling the evaluation of CRC values. An advantageous feature of this method is that it stops the cold wall effect from distorting the CRC calculation. Our suggested protocol results in a set of CRC values contributing to the characterization of small animal PET scanners. GATE simulations were also performed to validate the new method and verify the evaluated CRC values. We also demonstrated that the numerical values of this parameter depend on the actual object contrast of the hot region(s) and this mainly comes from the spillover effect. This effect was also studied while analysing the background activity level around the hot rods. We revealed that the calculated background mean values depended on the target contrast in a scanner specific manner. Performing the artificially merged imaging procedure and additional simulations using the micro hollow sphere (MHS) phantom geometry, we also proved that the inactive wall around the hot spheres can have a remarkable impact on the calculated CRC. In conclusion, we have shown that the proposed artificial merging procedure and the commonly used NU4IQ phantom prescribed by the NEMA NU-4 can easily deliver reliable CRC data otherwise unavailable for the NU4IQ phantom in the conventional protocol or the MHS phantom. (paper)

  3. Lutetium oxyorthosilicate (LSO) intrinsic activity correction and minimal detectable target activity study for SPECT imaging with a LSO-based animal PET scanner

    Science.gov (United States)

    Yao, Rutao; Ma, Tianyu; Shao, Yiping

    2008-08-01

    This work is part of a feasibility study to develop SPECT imaging capability on a lutetium oxyorthosilicate (LSO) based animal PET system. The SPECT acquisition was enabled by inserting a collimator assembly inside the detector ring and acquiring data in singles mode. The same LSO detectors were used for both PET and SPECT imaging. The intrinsic radioactivity of 176Lu in the LSO crystals, however, contaminates the SPECT data, and can generate image artifacts and introduce quantification error. The objectives of this study were to evaluate the effectiveness of a LSO background subtraction method, and to estimate the minimal detectable target activity (MDTA) of image object for SPECT imaging. For LSO background correction, the LSO contribution in an image study was estimated based on a pre-measured long LSO background scan and subtracted prior to the image reconstruction. The MDTA was estimated in two ways. The empirical MDTA (eMDTA) was estimated from screening the tomographic images at different activity levels. The calculated MDTA (cMDTA) was estimated from using a formula based on applying a modified Currie equation on an average projection dataset. Two simulated and two experimental phantoms with different object activity distributions and levels were used in this study. The results showed that LSO background adds concentric ring artifacts to the reconstructed image, and the simple subtraction method can effectively remove these artifacts—the effect of the correction was more visible when the object activity level was near or above the eMDTA. For the four phantoms studied, the cMDTA was consistently about five times of the corresponding eMDTA. In summary, we implemented a simple LSO background subtraction method and demonstrated its effectiveness. The projection-based calculation formula yielded MDTA results that closely correlate with that obtained empirically and may have predicative value for imaging applications.

  4. Lutetium oxyorthosilicate (LSO) intrinsic activity correction and minimal detectable target activity study for SPECT imaging with a LSO-based animal PET scanner

    International Nuclear Information System (INIS)

    This work is part of a feasibility study to develop SPECT imaging capability on a lutetium oxyorthosilicate (LSO) based animal PET system. The SPECT acquisition was enabled by inserting a collimator assembly inside the detector ring and acquiring data in singles mode. The same LSO detectors were used for both PET and SPECT imaging. The intrinsic radioactivity of 176Lu in the LSO crystals, however, contaminates the SPECT data, and can generate image artifacts and introduce quantification error. The objectives of this study were to evaluate the effectiveness of a LSO background subtraction method, and to estimate the minimal detectable target activity (MDTA) of image object for SPECT imaging. For LSO background correction, the LSO contribution in an image study was estimated based on a pre-measured long LSO background scan and subtracted prior to the image reconstruction. The MDTA was estimated in two ways. The empirical MDTA (eMDTA) was estimated from screening the tomographic images at different activity levels. The calculated MDTA (cMDTA) was estimated from using a formula based on applying a modified Currie equation on an average projection dataset. Two simulated and two experimental phantoms with different object activity distributions and levels were used in this study. The results showed that LSO background adds concentric ring artifacts to the reconstructed image, and the simple subtraction method can effectively remove these artifacts-the effect of the correction was more visible when the object activity level was near or above the eMDTA. For the four phantoms studied, the cMDTA was consistently about five times of the corresponding eMDTA. In summary, we implemented a simple LSO background subtraction method and demonstrated its effectiveness. The projection-based calculation formula yielded MDTA results that closely correlate with that obtained empirically and may have predicative value for imaging applications

  5. In vivo imaging and quantitative analysis of TSPO in rat peripheral tissues using small-animal PET with [18F]FEDAC

    International Nuclear Information System (INIS)

    Introduction: The translocator protein (18 kDa) (TSPO) is widely expressed in peripheral tissues, including the heart, lung, and kidney. Our laboratory developed N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[18F]fluoroethyl) -8-oxo-2-phenyl-9H-purin-9-yl]acetamide ([18F]FEDAC) as a TSPO positron emission tomography (PET) ligand. Here, using small-animal PET with [18F]FEDAC, we performed TSPO imaging and quantitative analysis of TSPO binding in rat peripheral tissues. Methods: The in vivo distribution and kinetics of [18F]FEDAC were measured in rat peripheral tissues (heart, lung and kidney). Using the in vivo pseudo-equilibrium method, TSPO binding parameters [TSPO density (Bmax), dissociation constant (KD)] and receptor occupancy were estimated in these peripheral tissues. Results: [18F]FEDAC was highly distributed in the lung, heart and kidney, and these TSPO-enriched tissues could be clearly visualized. The kinetics of this radioligand in these tissues was rapid, which is suitable for the determination of in vivo TSPO binding parameters and receptor occupancy. The Bmax value of TSPO in the heart, lung, and kidney was 393, 141, and 158 pmol/ml, respectively. The KD value of the radioligand in the heart, lung, and kidney was 119, 36 and 123 nM, respectively. By pretreatment with 5 mg/kg Ro 5-4864 (a TSPO ligand), about 90% of binding sites for TSPO in the heart and lung were occupied. In the kidney, the binding sites were completely occupied by 5 mg/kg Ro 5-4864. Conclusions: [18F]FEDAC is a suitable PET ligand for TSPO imaging and quantitative analysis of TSPO binding in rat peripheral tissues. The utilization of [18F]FEDAC-PET and the pseudo-equilibrium method can contribute to the study of the TSPO function and evaluate the in vivo binding parameters and receptor occupancy of TSPO therapeutic compounds.

  6. Animal biodistribution,safety and validation study of dopamine transporter PET imaging agent 18F-FECNT

    Institute of Scientific and Technical Information of China (English)

    WANG Songpei; CHEN Zhengping; LI Xiaomin; TANG Jie; LILT Chunyi; ZOU Meifen; PAN Donghui; LU Chunxiong; XU Yuping; XU Xijie; ZHOU Xingqin; JIN Jian

    2009-01-01

    This work was to investigate the pharmacologic characteristics of 18F-FECNT (2β-carbomethoxy-3β-(4-chlorophenyl)-8-(2-[18F]fluorcethyl)nortropane) as a dopamine transporter (DAT) PET imaging agent.Its partition coefficients were determined in n-octanol and phosphate buffer (PB) (pH 7.0 and pH 7.4).6-Hydroxydopamine (6-OHDA) left-sided lesioned Parkinsonian rats were established and validated by rotational behavior tests.Biodistribution in vivo in mice,autoradiography in normal and hemi-Parkinsonian rat brains,and toxicity test were performed.The results showed that partition coefficients were 34.14 (pH 7.0) and 56.41 (pH 7.4),respectively.Biodistribution exhibited rapid uptake and favorable retention in the mice brains.The major radioactivity was metabolized by the hepatic system.The autoradiography showed that 18F-FECNT was highly concentrated in striaturn,and that the left and the tight striatal uptake were symmetrical in normal SD rat brains.In left-sided lesioned PD rat brains,the striatal uptake of 18F-FECNT bilaterally decreased in comparison with normal rats.No significant uptake was visible in the 6-OHDA lesioned-sided striatal areas.The results demonstrated that 18F-FECNT binds to DAT was specific.Toxicity trial displayed that the acceptable dose per kilogram to mice was 625 times greater than that to human.These indicate that 18F-FECNT is a potentially safe and useful DAT PET imaging agent in the brain.

  7. Towards very high resolution RPC-PET for small animals

    International Nuclear Information System (INIS)

    We present imaging results of needle-like and planar 22Na sources obtained with a prototype of a high-acceptance small-animal positron emission tomograph based on resistive plate chambers (RPC-PET). The maximum-likelihood expectation-maximization (MLEM) reconstruction of the acquired data yielded an excellent and stable resolution of 0.4 mm FWHM

  8. PET and PET/CT for imaging of prostate cancer

    International Nuclear Information System (INIS)

    This review article provides an overview of the current literature data regarding the value of PET and PET/CT for imaging of prostate cancer. Most widely used PET tracers for prostate cancer imaging are 11C-acetate and 11C- or 18F-labeled choline. Available literature data on the performance of PET and PET/CT in the detection of the primary malignancy as well as local or distant metastases are presented and discussed. In addition, our own preliminary results regarding the diagnostic efficacy of 11C-choline PET and PET/CT in 43 patients with suspected prostate cancer are provided. The prevalence of prostate cancer in this patient sample was 55.8%. PET and PET/CT showed a sensitivity of 88% with a specificity of 63% in the detection of the primary prostate cancer. The sensitivity in the detection of metastatic spread was 77% and no false-positives were found. The possible value and limitations of combined PET/CT systems when compared to stand alone PET scanners are discussed. PET and PET/CT is at present the single imaging modality providing functional information not only regarding the primary malignancy but also its metastases. This unique feature distinguishes PET from MRI complemented with magnetic resonance spectroscopy - a competing procedure. Our own results as well as the still limited literature data suggest, that PET and PET/CT may prove to be useful methods for imaging of prostate cancer. (orig.)

  9. In vivo imaging and quantitative analysis of TSPO in rat peripheral tissues using small-animal PET with [{sup 18}F]FEDAC

    Energy Technology Data Exchange (ETDEWEB)

    Yanamoto, Kazuhiko; Kumata, Katsushi; Fujinaga, Masayuki [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan); Nengaki, Nobuki [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan); SHI Accelerator Service Co., Ltd., Shinagawa-ku, Tokyo, 141-0032 (Japan); Takei, Makoto [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan); Tokyo Nuclear Service Co., Ltd., Taito-ku, Tokyo, 110-0016 (Japan); Wakizaka, Hidekatsu [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan); Hosoi, Rie; Momosaki, Sotaro [Division of Health Sciences, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871 (Japan); Yamasaki, Tomoteru; Yui, Joji; Kawamura, Kazunori; Hatori, Akiko [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan); Inoue, Osamu [Division of Health Sciences, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871 (Japan); Zhang, Ming-Rong, E-mail: zhang@nirs.go.j [Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan)

    2010-10-15

    Introduction: The translocator protein (18 kDa) (TSPO) is widely expressed in peripheral tissues, including the heart, lung, and kidney. Our laboratory developed N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[{sup 18}F]fluoroethyl) -8-oxo-2-phenyl-9H-purin-9-yl]acetamide ([{sup 18}F]FEDAC) as a TSPO positron emission tomography (PET) ligand. Here, using small-animal PET with [{sup 18}F]FEDAC, we performed TSPO imaging and quantitative analysis of TSPO binding in rat peripheral tissues. Methods: The in vivo distribution and kinetics of [{sup 18}F]FEDAC were measured in rat peripheral tissues (heart, lung and kidney). Using the in vivo pseudo-equilibrium method, TSPO binding parameters [TSPO density (B{sub max}), dissociation constant (K{sub D})] and receptor occupancy were estimated in these peripheral tissues. Results: [{sup 18}F]FEDAC was highly distributed in the lung, heart and kidney, and these TSPO-enriched tissues could be clearly visualized. The kinetics of this radioligand in these tissues was rapid, which is suitable for the determination of in vivo TSPO binding parameters and receptor occupancy. The B{sub max} value of TSPO in the heart, lung, and kidney was 393, 141, and 158 pmol/ml, respectively. The K{sub D} value of the radioligand in the heart, lung, and kidney was 119, 36 and 123 nM, respectively. By pretreatment with 5 mg/kg Ro 5-4864 (a TSPO ligand), about 90% of binding sites for TSPO in the heart and lung were occupied. In the kidney, the binding sites were completely occupied by 5 mg/kg Ro 5-4864. Conclusions: [{sup 18}F]FEDAC is a suitable PET ligand for TSPO imaging and quantitative analysis of TSPO binding in rat peripheral tissues. The utilization of [{sup 18}F]FEDAC-PET and the pseudo-equilibrium method can contribute to the study of the TSPO function and evaluate the in vivo binding parameters and receptor occupancy of TSPO therapeutic compounds.

  10. Design of a small animal MR compatible PET scanner

    International Nuclear Information System (INIS)

    Using a combination of Monte-Carlo simulations and experimental measurements, the authors have designed a small animal MR compatible PET (McPET) scanner for simultaneous PET and MR imaging of mice and rats in vivo. The scanner consists of one ring of 480 LSO crystals arranged in 3 layers with 160 crystals per layer. The crystal dimensions are 2 x 3 x 7.5 mm3. This was based on a target resolution of 2.5 mm and simulations showing that a depth of 7.5 mm avoided significant depth of interaction effects across the desired field of view. The system diameter of 11.2 cm is large enough to accommodate the animal positioned inside a stereotactic frame. Each crystal will be coupled through 2 mm diameter optical fibers to multi-channel PMT's which reside outside the main magnetic field. Through 50 cm of optical fiber, a photopeak is clearly seen and the measured energy resolution is 25%. Prototype optical fiber connectors have been tested to increase the flexibility of the system and result in a light loss of only 6%. The proposed system will have adequate resolution and sensitivity for a number of applications in small animals and will be the first practical device for simultaneous in vivo imaging with PET and MR

  11. Important bacterial infections transmitted to humans from pet animals

    OpenAIRE

    Gökçen Dinç; Mehmet Doğanay; Müjgan İzgür

    2015-01-01

    In recent years, pets have started to be more commonly in family life, in our country and also all over the world. Previously, animals such as cats, dogs, birds have been ownered more frequently, but today pet range increased remarkably and the animals like hamsters, mice, rats, snakes, lizards, alligators have started to been preferred. Pet animals provide people feel better as psychological and physiological. It is mentioned that pet owners have lower blood pressure ...

  12. MR-based Motion Correction for PET Imaging

    Science.gov (United States)

    Ouyang, Jinsong; Li, Quanzheng; Fakhri, Georges El

    2012-01-01

    PET image quality is limited by patient motion. Emission data are blurred due to cardiac and/or respiratory motion. Although spatial resolution is 4 mm for standard clinical whole-body PET scanners, the effective resolution can be a low as 1 cm due to motion. Additionally, the deformation of attenuation medium causes image artifacts. Previously, gating is used to “freeze” the motion, but leads to significantly increased noise level. Simultaneous PET-MR modality offers a new way to perform PET motion correction. MR can be used to measure 3D motion fields, which can then be incorporated into the iterative PET reconstruction to obtain motion corrected PET images. In this report, we present MR imaging techniques to acquire dynamic images, a non-rigid image registration algorithm to extract motion fields from acquired MR images, and a PET reconstruction algorithm with motion correction. We also present results from both phantom and in-vivo animal PET-MR studies. We demonstrate that MR-based PET motion correction using simultaneous PET-MR improves image quality and lesion detectability compared to gating and to no motion correction. PMID:23178089

  13. Multi-modality PET-CT imaging of breast cancer in an animal model using nanoparticle x-ray contrast agent and 18F-FDG

    Science.gov (United States)

    Badea, C. T.; Ghaghada, K.; Espinosa, G.; Strong, L.; Annapragada, A.

    2011-03-01

    Multi-modality PET-CT imaging is playing an important role in the field of oncology. While PET imaging facilitates functional interrogation of tumor status, the use of CT imaging is primarily limited to anatomical reference. In an attempt to extract comprehensive information about tumor cells and its microenvironment, we used a nanoparticle xray contrast agent to image tumor vasculature and vessel 'leakiness' and 18F-FDG to investigate the metabolic status of tumor cells. In vivo PET/CT studies were performed in mice implanted with 4T1 mammary breast cancer cells.Early-phase micro-CT imaging enabled visualization 3D vascular architecture of the tumors whereas delayedphase micro-CT demonstrated highly permeable vessels as evident by nanoparticle accumulation within the tumor. Both imaging modalities demonstrated the presence of a necrotic core as indicated by a hypo-enhanced region in the center of the tumor. At early time-points, the CT-derived fractional blood volume did not correlate with 18F-FDG uptake. At delayed time-points, the tumor enhancement in 18F-FDG micro-PET images correlated with the delayed signal enhanced due to nanoparticle extravasation seen in CT images. The proposed hybrid imaging approach could be used to better understand tumor angiogenesis and to be the basis for monitoring and evaluating anti-angiogenic and nano-chemotherapies.

  14. Attenuation correction for the NIH ATLAS small animal PET scanner

    CERN Document Server

    Yao, Rutao; Liow, JeihSan; Seidel, Jurgen

    2003-01-01

    We evaluated two methods of attenuation correction for the NIH ATLAS small animal PET scanner: 1) a CT-based method that derives 511 keV attenuation coefficients (mu) by extrapolation from spatially registered CT images; and 2) an analytic method based on the body outline of emission images and an empirical mu. A specially fabricated attenuation calibration phantom with cylindrical inserts that mimic different body tissues was used to derive the relationship to convert CT values to (I for PET. The methods were applied to three test data sets: 1) a uniform cylinder phantom, 2) the attenuation calibration phantom, and 3) a mouse injected with left bracket **1**8F right bracket FDG. The CT-based attenuation correction factors were larger in non-uniform regions of the imaging subject, e.g. mouse head, than the analytic method. The two methods had similar correction factors for regions with uniform density and detectable emission source distributions.

  15. A new generation of PET scanners for small animal studies

    International Nuclear Information System (INIS)

    Complete text of publication follows. Research on small animal PET scanners has been a hot topic in recent years. These devices are used in the preclinical phases of drug tests and during the development of new radiopharmaceuticals. They also provide a cost efficient way to test new materials, new design concepts and new technologies that later can be used to build more efficient human medical imaging devices. The development of a PET scanner requires expertise on different fields, therefore a consortium was formed that brought together Hungarian academic and industrial partners: the Nuclear Research Institute (which has experience in the development of nuclear detectors and data acquisition systems), the PET Center of the University of Debrecen (which has clinical experience in the application of nuclear imaging devices and background in image processing software), Mediso Ltd. (which has been developing, manufacturing, selling and servicing medical imaging devices since 1990) and other academic partners. This consortium has been working together since 2003: the knowledge base acquired during the development of our small animal PET scanners (miniPET-I and miniPET-II) is now being utilized to build a commercial multimodal human PET scanner. The operation of a PET scanner is based on the simultaneous detection ('coincidence') of two gamma photons originating from a positron annihilation. In traditional PET scanners coincidence is detected by a central unit during the measurement. In our system there is no such central module: all detected single gamma events are recorded (list mode data acquisition), and the list of events are processed using a computer cluster (built from PCs). The usage of independent detector modules and commercial components reduce both development and maintenance costs. Also, this mode of data acquisition is more suitable for development purposes, since once the data is collected and stored it can be used many times to test different signal

  16. Quantitative evaluation of PET image using event information bootstrap

    Science.gov (United States)

    Song, Hankyeol; Kwak, Shin Hye; Kim, Kyeong Min; Kang, Joo Hyun; Chung, Yong Hyun; Woo, Sang-Keun

    2016-04-01

    The purpose of this study was to enhance the effect in the PET image quality according to event bootstrap of small animal PET data. In order to investigate the time difference condition, realigned sinograms were generated from randomly sampled data set using bootstrap. List-mode data was obtained from small animal PET scanner for Ge-68 30 sec, Y-90 20 min and Y-90 60 min. PET image was reconstructed by Ordered Subset Expectation Maximization(OSEM) 2D with the list-mode format. Image analysis was investigated by Signal to Noise Ratio(SNR) of Ge-68 and Y-90 image. Non-parametric resampled PET image SNR percent change for the Ge-68 30 sec, Y-90 60 min, and Y-90 20 min was 1.69 %, 7.03 %, and 4.78 %, respectively. SNR percent change of non-parametric resampled PET image with time difference condition was 1.08 % for the Ge-68 30 sec, 6.74 % for the Y-90 60 min and 10.94 % for the Y-90 29 min. The result indicated that the bootstrap with time difference condition had a potential to improve a noisy Y-90 PET image quality. This method should be expected to reduce Y-90 PET measurement time and to enhance its accuracy.

  17. Early Detection of Tumor Response by FLT/MicroPET Imaging in a C26 Murine Colon Carcinoma Solid Tumor Animal Model

    Directory of Open Access Journals (Sweden)

    Wan-Chi Lee

    2011-01-01

    Full Text Available Fluorine-18 fluorodeoxyglucose (18F-FDG positron emission tomography (PET imaging demonstrated the change of glucose consumption of tumor cells, but problems with specificity and difficulties in early detection of tumor response to chemotherapy have led to the development of new PET tracers. Fluorine-18-fluorothymidine (18F-FLT images cellular proliferation by entering the salvage pathway of DNA synthesis. In this study, we evaluate the early response of colon carcinoma to the chemotherapeutic drug, lipo-Dox, in C26 murine colorectal carcinoma-bearing mice by 18F-FDG and 18F-FLT. The male BALB/c mice were bilaterally inoculated with 1×105 and 1×106 C26 tumor cells per flank. Mice were intravenously treated with 10 mg/kg lipo-Dox at day 8 after 18F-FDG and 18F-FLT imaging. The biodistribution of 18F-FDG and 18F-FLT were followed by the microPET imaging at day 9. For the quantitative measurement of microPET imaging at day 9, 18F-FLT was superior to 18F-FDG for early detection of tumor response to Lipo-DOX at various tumor sizes (<0.05. The data of biodistribution showed similar results with those from the quantification of SUV (standard uptake value by microPET imaging. The study indicates that 18F-FLT/microPET is a useful imaging modality for early detection of chemotherapy in the colorectal mouse model.

  18. Animal Models for imaging

    OpenAIRE

    Croft, Barbara Y.

    2002-01-01

    Animal models can be used in the study of disease. This chapter discusses imaging animal models to elucidate the process of human disease. The mouse is used as the primary model. Though this choice simplifies many research choices, it necessitates compromises for in vivo imaging. In the future, we can expect improvements in both animal models and imaging techniques.

  19. Diagnostic imaging of exotic pets

    International Nuclear Information System (INIS)

    Radiographic, ultrasonographic, and computed tomographic (CT) imaging are important diagnostic modalities in exotic pets. The use of appropriate radiographic equipment, film-screen combinations, and radiographic projections enhances the information obtained from radiographs. Both normal findings and common radiographic abnormalities are discussed. The use of ultrasonography and CT scanning for exotic small mammals and reptiles is described

  20. Construction and tests of demonstrator modules for a 3-D axial PET system for brain or small animal imaging

    CERN Document Server

    Chesi, E; Clinthorne, N; Pauss, P; Meddi, F; Beltrame, P; Kagan, H; Braem, A; Casella, C; Djambazov, G; Smith, S; Johnson, I; Lustermann, W; Weilhammer, P; Nessi-Tedaldi, F; Dissertori, G; Renker, D; Schneider, T; Schinzel, D; Honscheid, K; De Leo, R; Bolle, E; Fanti, V; Rafecas, M; Cochran, E; Rudge, A; Stapnes, S; Huh, S; Seguinot, J; Solevi, P; Joram, C; Oliver, J F

    2011-01-01

    The design and construction of a PET camera module with high sensitivity, full 3-D spatial reconstruction and very good energy resolution is presented. The basic principle consists of an axial arrangement of long scintillation crystals around the Field Of View (FOV), providing a measurement of the transverse coordinates of the interacting 511 keV gamma ray. On top of each layer of crystals, an array of Wave-Length Shifter (WLS) strips, which collect the light leaving the crystals sideways, is positioned orthogonal to the crystal direction. The signals in the WLS strips allow a precise measurement of the z (axial) co-ordinate of the 511 keV gamma-ray gamma impact. The construction of two modules used for demonstration of the concept is described. First preliminary results on spatial and energy resolution from one full module will be shown. (C) 2010 Elsevier B.V. All rights reserved.

  1. Construction and tests of demonstrator modules for a 3-D axial PET system for brain or small animal imaging

    International Nuclear Information System (INIS)

    The design and construction of a PET camera module with high sensitivity, full 3-D spatial reconstruction and very good energy resolution is presented. The basic principle consists of an axial arrangement of long scintillation crystals around the Field Of View (FOV), providing a measurement of the transverse coordinates of the interacting 511 keV gamma ray. On top of each layer of crystals, an array of Wave-Length Shifter (WLS) strips, which collect the light leaving the crystals sideways, is positioned orthogonal to the crystal direction. The signals in the WLS strips allow a precise measurement of the z (axial) co-ordinate of the 511 keV γ-ray gamma impact. The construction of two modules used for demonstration of the concept is described. First preliminary results on spatial and energy resolution from one full module will be shown.

  2. PET/MR Imaging in Heart Disease.

    Science.gov (United States)

    Rischpler, Christoph; Nekolla, Stephan G

    2016-10-01

    Hybrid PET/MR imaging is a complex imaging modality that has raised high expectations not only for oncological and neurologic imaging applications, but also for cardiac imaging applications. Initially, physicians and physicists had to become accustomed to technical challenges including attenuation correction, gating, and more complex workflow and more elaborate image analysis as compared with PET/CT or standalone MR imaging. PET/MR imaging seems to be particularly valuable to assess inflammatory myocardial diseases (such as sarcoidosis), to cross-validate PET versus MR imaging data (eg, myocardial perfusion imaging), and to help validate novel biomarkers of various disease states (eg, postinfarction inflammation). PMID:27593250

  3. Neurotransmission imaging by PET

    International Nuclear Information System (INIS)

    PET studies on neurotransmission in psychological disorders to evaluate abnormal neurotransmission and therapeutic effects are thoroughly reviewed by type of major neurotransmitters. Studies on dopaminergic neurotransmission have focused on the function of dopamine D2 receptors, receptor subtypes, such as the D1 receptor, and ligands, such as transporters. PET studies of dopamine D2 receptor, which began in the early 1980s, have predominantly been performed in schizophrenia, and most have failed to detect any statistically significant differences between schizophrenia patients and controls. The studies in the early 1980s were performed by using [11C]N-methyl-spiperone (NMSP) and [11C]raclopride, ligands for striatal dopamine D2 receptors. [11C]FLB457, which has much higher affinity for D2 receptors than raclopride, began to be used in the 1990s. Dopamine D2 occupancy after drug ingestion has also been investigated to clarify the mechanisms and effects of antipsychotic drugs, and there have also been studies on the effect of aging and personality traits on dopamine D2 receptor levels in healthy subjects. In studies on dopamine receptor subtypes other than D2, dopamine D1 receptors have been studied in connection with assessments of cognitive functions. Most studies on dopamine transporters have been related to drug dependence. Serotonin 5-HT2A receptors have been studied with [11C]NMSP in schizophrenia patients, while studies of another serotonin receptor subtype, 5-HT1A receptors, have been mainly conducted in patients with depression. [11C]NMSP PET showed no difference between schizophrenia patients who had not undergone phamacotherapy and normal subjects. Because serotonin selective reuptake inhibitors (SSRIs) affect serotonin transporters, and abnormalities in serotonin transporters detected in mood disorders, PET ligands for serotonin transporters have increasingly been developed, and serotonin transporters have recently begun to be examined. GABA has been

  4. Neurotransmission imaging by PET

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Akihiro; Suhara, Tetsuya [National Inst. of Radiological Sciences, Chiba (Japan)

    2001-08-01

    PET studies on neurotransmission in psychological disorders to evaluate abnormal neurotransmission and therapeutic effects are thoroughly reviewed by type of major neurotransmitters. Studies on dopaminergic neurotransmission have focused on the function of dopamine D{sub 2} receptors, receptor subtypes, such as the D{sub 1} receptor, and ligands, such as transporters. PET studies of dopamine D{sub 2} receptor, which began in the early 1980s, have predominantly been performed in schizophrenia, and most have failed to detect any statistically significant differences between schizophrenia patients and controls. The studies in the early 1980s were performed by using [{sup 11}C]N-methyl-spiperone (NMSP) and [{sup 11}C]raclopride, ligands for striatal dopamine D{sub 2} receptors. [{sup 11}C]FLB457, which has much higher affinity for D{sub 2} receptors than raclopride, began to be used in the 1990s. Dopamine D{sub 2} occupancy after drug ingestion has also been investigated to clarify the mechanisms and effects of antipsychotic drugs, and there have also been studies on the effect of aging and personality traits on dopamine D{sub 2} receptor levels in healthy subjects. In studies on dopamine receptor subtypes other than D{sub 2}, dopamine D{sub 1} receptors have been studied in connection with assessments of cognitive functions. Most studies on dopamine transporters have been related to drug dependence. Serotonin 5-HT{sub 2A} receptors have been studied with [{sup 11}C]NMSP in schizophrenia patients, while studies of another serotonin receptor subtype, 5-HT{sub 1A} receptors, have been mainly conducted in patients with depression. [{sup 11}C]NMSP PET showed no difference between schizophrenia patients who had not undergone phamacotherapy and normal subjects. Because serotonin selective reuptake inhibitors (SSRIs) affect serotonin transporters, and abnormalities in serotonin transporters detected in mood disorders, PET ligands for serotonin transporters have increasingly

  5. FDG PET imaging dementia

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Byeong Cheol [Kyungpook National University Medical School and Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2007-04-15

    Dementia is a major burden for many countries including South Korea, where life expectancy is continuously growing and the proportion of aged people is rapidly growing. Neurodegenerative disorders, such as, Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia. Parkinson disease, progressive supranuclear palsy, corticobasal degeneration, Huntington disease, can cause dementia, and cerebrovascular disease also can cause dementia. Depression or hypothyroidism also can cause cognitive deficits, but they are reversible by management of underlying cause unlike the forementioned dementias. Therefore these are called pseudodementia. We are entering an era of dementia care that will be based upon the identification of potentially modifiable risk factors and early disease markers, and the application of new drugs postpone progression of dementias or target specific proteins that cause dementia. Efficient pharmacologic treatment of dementia needs not only to distinguish underlying causes of dementia but also to be installed as soon as possible. Therefore, differential diagnosis and early diagnosis of dementia are utmost importance. F-18 FDG PET is useful for clarifying dementing diseases and is also useful for early detection of the disease. Purpose of this article is to review the current value of FDG PET for dementing diseases including differential diagnosis of dementia and prediction of evolving dementia.

  6. FDG PET imaging dementia

    International Nuclear Information System (INIS)

    Dementia is a major burden for many countries including South Korea, where life expectancy is continuously growing and the proportion of aged people is rapidly growing. Neurodegenerative disorders, such as, Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia. Parkinson disease, progressive supranuclear palsy, corticobasal degeneration, Huntington disease, can cause dementia, and cerebrovascular disease also can cause dementia. Depression or hypothyroidism also can cause cognitive deficits, but they are reversible by management of underlying cause unlike the forementioned dementias. Therefore these are called pseudodementia. We are entering an era of dementia care that will be based upon the identification of potentially modifiable risk factors and early disease markers, and the application of new drugs postpone progression of dementias or target specific proteins that cause dementia. Efficient pharmacologic treatment of dementia needs not only to distinguish underlying causes of dementia but also to be installed as soon as possible. Therefore, differential diagnosis and early diagnosis of dementia are utmost importance. F-18 FDG PET is useful for clarifying dementing diseases and is also useful for early detection of the disease. Purpose of this article is to review the current value of FDG PET for dementing diseases including differential diagnosis of dementia and prediction of evolving dementia

  7. The Power of Pets: How Animals Affect Family Relationships

    OpenAIRE

    Geller, Krista Scott

    2002-01-01

    THE POWER OF PETS: HOW ANIMALS AFFECT FAMILY RELATIONSHIPS By Krista Scott Geller Katherine R. Allen, Committee Chair Department of Human Development Virginia polytechnic Institute and State University (ABSTRACT) This study was designed to explore the importance a pet can have on someoneâ s life, including ways a pet affects the relationships an individual has with other family members. This study assessed how pets can be influential in peopleâ s lives, espe...

  8. Proton Therapy Verification with PET Imaging

    OpenAIRE

    Zhu, Xuping; Fakhri, Georges El

    2013-01-01

    Proton therapy is very sensitive to uncertainties introduced during treatment planning and dose delivery. PET imaging of proton induced positron emitter distributions is the only practical approach for in vivo, in situ verification of proton therapy. This article reviews the current status of proton therapy verification with PET imaging. The different data detecting systems (in-beam, in-room and off-line PET), calculation methods for the prediction of proton induced PET activity distributions...

  9. Imaging of Awake Animals

    OpenAIRE

    Wilkinson, Thomas

    2015-01-01

    The 3Rs of reduction, refinement and replacement are the guiding principles of animal research and embedded in national and international legislation regulating the use of animals in scientific procedures. Awake imaging by MRI of rodents can offer a reduction by increasing the quality of scientific data through longitudinal imaging using less animals by avoiding a serial sacrifice design and refinement through reducing the stressful effects animals are exposed to, in comparison to existing mo...

  10. Studies oriented to optimize the image quality of the small animal PET: Clear PET, modifying some of the parameters of the reconstruction algorithm IMF-OSEM 3D on the data acquisition simulated with GAMOS; Estudios para la optimizaciOn de la calidad de imagen en el escaner ClearPET, modifi cando parametros del algoritmo IMF-OSEM 3D sobre adquisiciones simuladas con GAMOS

    Energy Technology Data Exchange (ETDEWEB)

    Canadas, M.; Mendoza, J.; Embid, M.

    2007-09-27

    This report presents studies oriented to optimize the image quality of the small animal PET: Clear- PET. Certain figures of merit (FOM) were used to assess a quantitative value of the contrast and delectability of lesions. The optimization was carried out modifying some of the parameters in the reconstruction software of the scanner, imaging a mini-Derenzo phantom and a cylinder phantom with background activity and two hot spheres. Specifically, it was evaluated the incidence of the inter-update Metz filter (IMF) inside the iterative reconstruction algorithm 3D OSEM. The data acquisition was simulated using the GAMOS framework (Monte Carlo simulation). Integrating GAMOS output with the reconstruction software of the scanner was an additional novelty of this work, to achieve this, data sets were written with the list-mode format (LMF) of ClearPET. In order to verify the optimum values obtained, we foresee to make real acquisitions in the ClearPET of CIEMAT. (Author) 17 refs.

  11. Questions and Answers about Ebola, Pets, and Other Animals

    Science.gov (United States)

    ... Questions and Answers about Ebola, Pets, and Other Animals Language: English Español Français Recommend on Facebook Tweet Share Compartir How are animals involved in Ebola outbreaks? Because the natural reservoir ...

  12. Radiosynthesis and evaluation of [{sup 61}Cu]-9,10-phenanthrenequinone thiosemicarbazone in fibrosarcoma-bearing animals for PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jalilian, A.R.; Akhlaghi, M.; Kamali-Dehghan, M.; Shafaii, K.; Moradkhani, S. [Agricultural, Medical and Industrial Research School (AMIRS-NSTRI), Karaj (Iran); Emami, A. [Islamic Azad University, Tehran (Iran). Pharmaceutical Sciences Branch

    2010-07-01

    [{sup 61}Cu]-9,10-Phenanthrenequinone thiosemicarbazone ({sup 61}Cu-PQTS), a radiolabeled anticancer compound was prepared for malignant tissue imaging studies. Copper-61 was produced via the {sup nat}Zn(p, x){sup 61}Cu nuclear reaction in a 30 MeV cyclotron (150 {mu}A irradiation for 76 min, radionuclidic purity >95%). {sup 61}Cu-PQTS was prepared from in-house synthesized PQTS. Quality control was performed using ITLC. The biodistribution of the tracer was compared to the biodistribution of cationic copper-61 in healthy controls. {sup 61}Cu-PQTS was then administered to fibrosarcoma-bearing mice for biodistribution and co-incidence imaging studies. {sup 61}Cu-PQTS demonstrated significant tumor uptake of 2.1% ID/g and the tumor was clearly visualized in a fibrosarcoma model. (orig.)

  13. Radiosynthesis and evaluation of [61Cu]-9,10-phenanthrenequinone thiosemicarbazone in fibrosarcoma-bearing animals for PET imaging

    International Nuclear Information System (INIS)

    [61Cu]-9,10-Phenanthrenequinone thiosemicarbazone (61Cu-PQTS), a radiolabeled anticancer compound was prepared for malignant tissue imaging studies. Copper-61 was produced via the natZn(p, x)61Cu nuclear reaction in a 30 MeV cyclotron (150 μA irradiation for 76 min, radionuclidic purity >95%). 61Cu-PQTS was prepared from in-house synthesized PQTS. Quality control was performed using ITLC. The biodistribution of the tracer was compared to the biodistribution of cationic copper-61 in healthy controls. 61Cu-PQTS was then administered to fibrosarcoma-bearing mice for biodistribution and co-incidence imaging studies. 61Cu-PQTS demonstrated significant tumor uptake of 2.1% ID/g and the tumor was clearly visualized in a fibrosarcoma model. (orig.)

  14. Simultaneous PET/MR body imaging in rats. Initial experiences with an integrated PET/MRI scanner

    International Nuclear Information System (INIS)

    We recently developed an integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) (iPET/MRI) scanner for small animals, which had relatively large field-of-view (FOV) covering up to the size of a rat body. The purpose of this study was to report results of simultaneous PET/MRI of a rat body using this scanner with some radiotracers. C-11-methionine (MET), F-18-fluorodeoxyglucose (FDG), or F-18-sodium fluoride (NaF) was injected as a radiotracer for PET portion in addition to gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid, a hepatobiliary contrast agent, for MRI portion. Simultaneous PET/MRI was performed in normal rats. PET, MRI, and co-registered fusion images were evaluated regarding image quality and feasibility for rat imaging studies. MET uptake was clearly shown in the liver and pancreas, which was confirmed with magnetic resonance (MR) and fused PET/MR images. PET/MR images depicted intense FDG uptake in the brain, Harderian glands, and myocardium. NaF uptake was observed in all bones and joints within FOV, except in ribs, which was well recognized with the help of MR and fused PET/MR images. This study demonstrated that simultaneous PET/MRI with an integrated dual-modality molecular imaging scanner was a feasible technique for imaging studies targeting on a rat body. However, further developments including attenuation correction methods are required to use this technique routinely in rat imaging studies. (author)

  15. An introduction to PET/CT imaging

    International Nuclear Information System (INIS)

    Since its introduction in 1998, dual-modality PET/CT imaging has received great attention in the medical community. Patients are examined with both CT and PET in a whole-body single examination in the same scanner and fusion can be obtained directly obviating the need for software registration. The CT images are used for anatomic reference of the tracer uptake patterns imaged in PET, as well as for attenuation correction of the PET data. This review discusses the technical background of PET with F-18-fluorodeoxyglucose, CT and combined PET/CT devices. Clinical applications in oncology are considered. Fusion of the anatomic information provided by CT and the metabolic information provided by PET in PET/CT imaging allows a higher diagnostic accuracy for lesion localisation than PET plus CT performed independently. Image artefacts can result from CT-based attenuation methodology that can overcorrect dense objects generating hot spot artefacts in attenuation correction PET images and mismatches in CT and PET studies due to respiratory movements and the different patient positioning between both examinations. (author)

  16. Molecular Imaging Challenges With PET

    CERN Document Server

    Lecoq, P

    2010-01-01

    The future trends in molecular imaging and associated challenges for in-vivo functional imaging are illustrated on the basis of a few examples, such as atherosclerosis vulnerable plaques imaging or stem cells tracking. A set of parameters are derived to define the specifications of a new generation of in-vivo imaging devices in terms of sensitivity, spatial resolution and signal-to-noise ratio. The limitations of strategies used in present PET scanners are discussed and new approaches are proposed taking advantage of recent progress on materials, photodetectors and readout electronics. A special focus is put on metamaterials, as a new approach to bring more functionality to detection devices. It is shown that the route is now open towards a fully digital detector head with very high photon counting capability over a large energy range, excellent timing precision and possibility of imaging the energy deposition process.

  17. A generalized method of converting CT image to PET linear attenuation coefficient distribution in PET/CT imaging

    International Nuclear Information System (INIS)

    The accuracy of attenuation correction in positron emission tomography scanners depends mainly on deriving the reliable 511-keV linear attenuation coefficient distribution in the scanned objects. In the PET/CT system, the linear attenuation distribution is usually obtained from the intensities of the CT image. However, the intensities of the CT image relate to the attenuation of photons in an energy range of 40 keV–140 keV. Before implementing PET attenuation correction, the intensities of CT images must be transformed into the PET 511-keV linear attenuation coefficients. However, the CT scan parameters can affect the effective energy of CT X-ray photons and thus affect the intensities of the CT image. Therefore, for PET/CT attenuation correction, it is crucial to determine the conversion curve with a given set of CT scan parameters and convert the CT image into a PET linear attenuation coefficient distribution. A generalized method is proposed for converting a CT image into a PET linear attenuation coefficient distribution. Instead of some parameter-dependent phantom calibration experiments, the conversion curve is calculated directly by employing the consistency conditions to yield the most consistent attenuation map with the measured PET data. The method is evaluated with phantom experiments and small animal experiments. In phantom studies, the estimated conversion curve fits the true attenuation coefficients accurately, and accurate PET attenuation maps are obtained by the estimated conversion curves and provide nearly the same correction results as the true attenuation map. In small animal studies, a more complicated attenuation distribution of the mouse is obtained successfully to remove the attenuation artifact and improve the PET image contrast efficiently. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. A generalized method of converting CT image to PET linear attenuation coefficient distribution in PET/CT imaging

    Science.gov (United States)

    Wang, Lu; Wu, Li-Wei; Wei, Le; Gao, Juan; Sun, Cui-Li; Chai, Pei; Li, Dao-Wu

    2014-02-01

    The accuracy of attenuation correction in positron emission tomography scanners depends mainly on deriving the reliable 511-keV linear attenuation coefficient distribution in the scanned objects. In the PET/CT system, the linear attenuation distribution is usually obtained from the intensities of the CT image. However, the intensities of the CT image relate to the attenuation of photons in an energy range of 40 keV-140 keV. Before implementing PET attenuation correction, the intensities of CT images must be transformed into the PET 511-keV linear attenuation coefficients. However, the CT scan parameters can affect the effective energy of CT X-ray photons and thus affect the intensities of the CT image. Therefore, for PET/CT attenuation correction, it is crucial to determine the conversion curve with a given set of CT scan parameters and convert the CT image into a PET linear attenuation coefficient distribution. A generalized method is proposed for converting a CT image into a PET linear attenuation coefficient distribution. Instead of some parameter-dependent phantom calibration experiments, the conversion curve is calculated directly by employing the consistency conditions to yield the most consistent attenuation map with the measured PET data. The method is evaluated with phantom experiments and small animal experiments. In phantom studies, the estimated conversion curve fits the true attenuation coefficients accurately, and accurate PET attenuation maps are obtained by the estimated conversion curves and provide nearly the same correction results as the true attenuation map. In small animal studies, a more complicated attenuation distribution of the mouse is obtained successfully to remove the attenuation artifact and improve the PET image contrast efficiently.

  19. PET/CT Imaging in Mouse Models of Myocardial Ischemia

    Directory of Open Access Journals (Sweden)

    Sara Gargiulo

    2012-01-01

    Full Text Available Different species have been used to reproduce myocardial infarction models but in the last years mice became the animals of choice for the analysis of several diseases, due to their short life cycle and the possibility of genetic manipulation. Many techniques are currently used for cardiovascular imaging in mice, including X-ray computed tomography (CT, high-resolution ultrasound, magnetic resonance imaging, and nuclear medicine procedures. Cardiac positron emission tomography (PET allows to examine noninvasively, on a molecular level and with high sensitivity, regional changes in myocardial perfusion, metabolism, apoptosis, inflammation, and gene expression or to measure changes in anatomical and functional parameters in heart diseases. Currently hybrid PET/CT scanners for small laboratory animals are available, where CT adds high-resolution anatomical information. This paper reviews mouse models of myocardial infarction and discusses the applications of dedicated PET/CT systems technology, including animal preparation, anesthesia, radiotracers, and images postprocessing.

  20. Simultaneous ECG-gated PET imaging of multiple mice

    International Nuclear Information System (INIS)

    Introduction: We describe and illustrate a method for creating ECG-gated PET images of the heart for each of several mice imaged at the same time. The method is intended to increase “throughput” in PET research studies of cardiac dynamics or to obtain information derived from such studies, e.g. tracer concentration in end-diastolic left ventricular blood. Methods: An imaging bed with provisions for warming, anesthetic delivery, etc., was fabricated by 3D printing to allow simultaneous PET imaging of two side-by-side mice. After electrode attachment, tracer injection and placement of the animals in the scanner field of view, ECG signals from each animal were continuously analyzed and independent trigger markers generated whenever an R-wave was detected in each signal. PET image data were acquired in “list” mode and these trigger markers were inserted into this list along with the image data. Since each mouse is in a different spatial location in the FOV, sorting of these data using trigger markers first from one animal and then the other yields two independent and correctly formed ECG-gated image sequences that reflect the dynamical properties of the heart during an “average” cardiac cycle. Results: The described method yields two independent ECG-gated image sequences that exhibit the expected properties in each animal, e.g. variation of the ventricular cavity volumes from maximum to minimum and back during the cardiac cycle in the processed animal with little or no variation in these volumes during the cardiac cycle in the unprocessed animal. Conclusion: ECG-gated image sequences for each of several animals can be created from a single list mode data collection using the described method. In principle, this method can be extended to more than two mice (or other animals) and to other forms of physiological gating, e.g. respiratory gating, when several subjects are imaged at the same time

  1. Quantitative simultaneous PET-MR imaging

    Science.gov (United States)

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

    2014-06-01

    Whole-body PET is currently limited by the degradation due to patient motion. Respiratory motion degrades imaging studies of the abdomen. Similarly, both respiratory and cardiac motions significantly hamper the assessment of myocardial ischemia and/or metabolism in perfusion and viability cardiac PET studies. Based on simultaneous PET-MR, we have developed robust and accurate MRI methods allowing the tracking and measurement of both respiratory and cardiac motions during abdominal or cardiac studies. Our list-mode iterative PET reconstruction framework incorporates the measured motion fields into PET emission system matrix as well as the time-dependent PET attenuation map and the position dependent point spread function. Our method significantly enhances the PET image quality as compared to conventional methods.

  2. Principles of PET/MR Imaging.

    Science.gov (United States)

    Disselhorst, Jonathan A; Bezrukov, Ilja; Kolb, Armin; Parl, Christoph; Pichler, Bernd J

    2014-05-12

    Hybrid PET/MR systems have rapidly progressed from the prototype stage to systems that are increasingly being used in the clinics. This review provides an overview of developments in hybrid PET/MR systems and summarizes the current state of the art in PET/MR instrumentation, correction techniques, and data analysis. The strong magnetic field requires considerable changes in the manner by which PET images are acquired and has led, among others, to the development of new PET detectors, such as silicon photomultipliers. During more than a decade of active PET/MR development, several system designs have been described. The technical background of combined PET/MR systems is explained and related challenges are discussed. The necessity for PET attenuation correction required new methods based on MR data. Therefore, an overview of recent developments in this field is provided. Furthermore, MR-based motion correction techniques for PET are discussed, as integrated PET/MR systems provide a platform for measuring motion with high temporal resolution without additional instrumentation. The MR component in PET/MR systems can provide functional information about disease processes or brain function alongside anatomic images. Against this background, we point out new opportunities for data analysis in this new field of multimodal molecular imaging. PMID:24819419

  3. Small Animal Retinal Imaging

    Science.gov (United States)

    Choi, WooJhon; Drexler, Wolfgang; Fujimoto, James G.

    Developing and validating new techniques and methods for small animal imaging is an important research area because there are many small animal models of retinal diseases such as diabetic retinopathy, age-related macular degeneration, and glaucoma [1-6]. Because the retina is a multilayered structure with distinct abnormalities occurring in different intraretinal layers at different stages of disease progression, there is a need for imaging techniques that enable visualization of these layers individually at different time points. Although postmortem histology and ultrastructural analysis can be performed for investigating microscopic changes in the retina in small animal models, this requires sacrificing animals, which makes repeated assessment of the same animal at different time points impossible and increases the number of animals required. Furthermore, some retinal processes such as neurovascular coupling cannot be fully characterized postmortem.

  4. Whole animal imaging

    OpenAIRE

    Sandhu, Gurpreet Singh; Solorio, Luis; Broome, Ann-Marie; Salem, Nicolas; Kolthammer, Jeff; Shah, Tejas; Flask, Chris; Duerk, Jeffrey L.

    2010-01-01

    Translational research plays a vital role in understanding the underlying pathophysiology of human diseases, and hence development of new diagnostic and therapeutic options for their management. After creating an animal disease model, pathophysiologic changes and effects of a therapeutic intervention on them are often evaluated on the animals using immunohistologic or imaging techniques. In contrast to the immunohistologic techniques, the imaging techniques are noninvasive and hence can be us...

  5. A Review of Cancer Chemotherapy for Pet Animals

    OpenAIRE

    Norris, A. M.; Withrow, S.J.

    1984-01-01

    A review of the principles of cancer chemotherapy for pet animals is presented. The various pharmacological classes of antineoplastic drugs are described with specific references to those drugs that have been widely used in veterinary medicine.

  6. 15 CFR 265.43 - Pets and other animals.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Pets and other animals. 265.43 Section... animals. Except in connection with the conduct of official business on the site or with the approval of... person shall bring upon the site any cat, dog, or other animal, provided, however, that blind persons...

  7. Proton Therapy Verification with PET Imaging

    Science.gov (United States)

    Zhu, Xuping; Fakhri, Georges El

    2013-01-01

    Proton therapy is very sensitive to uncertainties introduced during treatment planning and dose delivery. PET imaging of proton induced positron emitter distributions is the only practical approach for in vivo, in situ verification of proton therapy. This article reviews the current status of proton therapy verification with PET imaging. The different data detecting systems (in-beam, in-room and off-line PET), calculation methods for the prediction of proton induced PET activity distributions, and approaches for data evaluation are discussed. PMID:24312147

  8. Increased brain metabolism after acute administration of the synthetic cannabinoid HU210: a small animal PET imaging study with 18F-FDG.

    Science.gov (United States)

    Nguyen, Vu H; Verdurand, Mathieu; Dedeurwaerdere, Stefanie; Wang, Hongqin; Zahra, David; Gregoire, Marie-Claude; Zavitsanou, Katerina

    2012-02-10

    Cannabis use has been shown to alter brain metabolism in both rat models and humans although the observations between both species are conflicting. In the present study, we examined the short term effects of a single-dose injection of the synthetic cannabinoid agonist HU210 on glucose metabolism in the rat brain using small animal (18)F-2-fluoro-deoxyglucose (FDG) Positron Emission Tomography (PET) 15 min (Day 1) and 24h (Day 2) post-injection of the agonist in the same animal. Young adult male Wistar rats received an intra-peritoneal injection of HU210 (100 μg/kg, n=7) or vehicle (n=5) on Day 1. Approximately 1mCi of (18)F-FDG was injected intravenously into each animal at 15 min (Day 1) and 24h (Day 2) post-injection of HU210. A 5-min Computer Tomography (CT) scan followed by a 20-min PET scan was performed 40 min after each (18)F-FDG injection. Standardised Uptake Values (SUVs) were calculated for 10 brain regions of interest (ROIs). Global increased SUVs in the whole brain, hence global brain metabolism, were observed following HU210 treatment on Day 1 compared to the controls (21%, PHU210 treated group returned to control levels (21-30% decrease compared to Day 1), in all ROIs investigated (PHU210 increases brain glucose metabolism in the rat brain shortly after administration, in line with normalised human in vivo studies, an effect that was no longer apparent 24 h later. PMID:22155282

  9. PET imaging using parkinsonian primate model

    International Nuclear Information System (INIS)

    Many animal models have been for studying neutrodegenerative diseases in humans. Among them, Parkinson's disease (PD) model in primates treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is expected to be valid and useful in the field of regenerative medicine. MPTP-treated monkeys demonstrate parkinsonian syndrome, such as tremor, dyskinesia, rigidity, immobility, caused by the degeneration of dopamine neurons at the nigrostriatal pathway. In this model, investigation of cognitive impairment that is one of the important aspects of PD could be possible. We evaluated the degeneration process of nigrostriatal dopamine neurons with positron emission tomography (PET) using unanesthetized MPTP-treated two cynomolgus monkeys (Macaca fascicularis). The tracers used were [11C]PE2I, [11C]DOPA, [11C]raclopride for monitoring dopamine transporter (DAT) densities, dopamine (DA) turnover, dopamine D2-receptor (D2R) densities, respectively. The gross behavioral observation was also performed referring to the criteria of the PD symptoms. The motor dysfunction was not clearly observed up to the cumulative doses of 3 mg/kg MPTP. This period was called 'asymptomatic period'. As a result of PET scans in the asymptomatic period, DAT densities and DA turnover had already decreased greatly, but D2R densities had not changed clearly. These findings suggest that PET imaging can delineate the dopaminergic dysfunction in vivo even in the asymptomatic period. In human study of PD, it is reported that parkinsonism is shown after great loss of dopaminergic neutrons as well as pre-synaptic dysfunction. MPTP-treated monkeys demonstrate the parkinsonian syndrome with the similar mechanism as human PD. It can be expected that PET study with MPTP-monkeys would provide important clues relevant to the underlying cause of PD and be useful for preclinical study of regenerative medicine in this disease. (author)

  10. PET-CT imaging in pediatric oncology

    OpenAIRE

    McCarville, M. Beth

    2009-01-01

    Abstract Positron emission tomography (PET)-computed tomography (CT) is emerging as a valuable tool for assessing a wide variety of pediatric malignancies, including lymphomas, soft-tissue tumors, and bone sarcomas. PET-CT may provide information that is not apparent on conventional imaging performed to stage these diseases and monitor their response to treatment. The use of PET-CT in children requires an awareness of the technical and logistical issues unique to this patient population. In a...

  11. Ready for prime time? Dual tracer PET and SPECT imaging

    Science.gov (United States)

    Fakhri, Georges El

    2012-01-01

    Dual isotope single photon emission computed tomography (SPECT) and dual tracer positron emission tomography (PET) imaging have great potential in clinical and molecular applications in the pediatric as well as the adult populations in many areas of brain, cardiac, and oncologic imaging as it allows the exploration of different physiological and molecular functions (e.g., perfusion, neurotransmission, metabolism, apoptosis, angiogenesis) under the same physiological and physical conditions. This is crucial when the physiological functions studied depend on each other (e.g., perfusion and metabolism) hence requiring simultaneous assessment under identical conditions, and can reduce greatly the quantitation errors associated with physical factors that can change between acquisitions (e.g., human subject or animal motion, change in the attenuation map as a function of time) as is detailed in this editorial. The clinical potential of simultaneous dual isotope SPECT, dual tracer PET and dual SPECT/PET imaging are explored and summarized. In this issue of AJNMMI (http://www.ajnmmi.us), Chapman et al. explore the feasibility of simultaneous and sequential SPECT/PET imaging and conclude that down-scatter and crosstalk from 511 keV photons preclude obtaining useful SPECT information in the presence of PET radiotracers. They report on an alternative strategy that consists of performing sequential SPECT and PET studies in hybrid microPET/SPECT/CT scanners, now widely available for molecular imaging. They validate their approach in a phantom consisting of a 96-well plate with variable 99mTc and 18F concentrations and illustrate the utility of such approaches in two sequential SPECT-PET/CT studies that include 99mTc-MAA/18F-NaF and 99mTc-Pentetate/18F-NaF. These approaches will need to be proven reproducible, accurate and robust to variations in the experimental conditions before they can be accepted by the molecular imaging community and be implemented in routine molecular

  12. 9.4–14.1 T small-animal PET-MR imaging: Feasibility analysis of LYSO APD readout via long signal lines

    Energy Technology Data Exchange (ETDEWEB)

    Neves, J.A., E-mail: janeves@lip.pt [LIP - Laboratory of Instrumentation and Experimental Particle Physics, Lisbon (Portugal); IST-UTL - Instituto Superior Técnico, Technical University of Lisbon, Lisbon (Portugal); Laboratory of Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne (Switzerland); Bugalho, R. [LIP - Laboratory of Instrumentation and Experimental Particle Physics, Lisbon (Portugal); IST-UTL - Instituto Superior Técnico, Technical University of Lisbon, Lisbon (Portugal); Gruetter, R. [Laboratory of Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne (Switzerland); Department of Radiology, University of Lausanne, Lausanne (Switzerland); Department of Radiology, University of Geneva, Geneva (Switzerland); Magill, A.W. [Laboratory of Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne (Switzerland); Department of Radiology, University of Lausanne, Lausanne (Switzerland); Ortigão, C.; Silva, J.C.; Silva, R. [LIP - Laboratory of Instrumentation and Experimental Particle Physics, Lisbon (Portugal); Varela, J. [LIP - Laboratory of Instrumentation and Experimental Particle Physics, Lisbon (Portugal); IST-UTL - Instituto Superior Técnico, Technical University of Lisbon, Lisbon (Portugal); CERN - European Organization for Nuclear Research, Geneva (Switzerland)

    2013-02-21

    In the present work we intend to assess the readout feasibility of Avalanche Photodiode (APD) detectors via long signal lines for the development of a combined small-animal PET-MR prototype based on the ClearPEM technology. The detection performance of a LYSO-APD module was evaluated reading out the APD charge signals to the front-end ASIC via an 80 mm length flexible flat-cable (FFC). Experimental results showed a time resolution of 5.06 ns for the detector module in double-readout mode, with a nonsignificant degradation of 8.4% with the introduction of the FFC. The energy resolution of the system was not degradated by the FFC.

  13. Simultaneous imaging using Si-PM-based PET and MRI for development of an integrated PET/MRI system

    International Nuclear Information System (INIS)

    The silicon photomultiplier (Si-PM) is a promising photo-detector for PET for use in magnetic resonance imaging (MRI) systems because it has high gain and is insensitive to static magnetic fields. Recently we developed a Si-PM-based depth-of-interaction PET system for small animals and performed simultaneous measurements by combining the Si-PM-based PET and the 0.15 T permanent MRI to test the interferences between the Si-PM-based PET and an MRI. When the Si-PM was inside the MRI and installed around the radio frequency (RF) coil of the MRI, significant noise from the RF sequence of the MRI was observed in the analog signals of the PET detectors. However, we did not observe any artifacts in the PET images; fluctuation increased in the count rate of the Si-PM-based PET system. On the MRI side, there was significant degradation of the signal-to-noise ratio (S/N) in the MRI images compared with those without PET. By applying noise reduction procedures, the degradation of the S/N was reduced. With this condition, simultaneous measurements of a rat brain using a Si-PM-based PET and an MRI were made with some degradation in the MRI images. We conclude that simultaneous measurements are possible using Si-PM-based PET and MRI. (note)

  14. PET imaging of adoptive progenitor cell therapies.

    Energy Technology Data Exchange (ETDEWEB)

    Gelovani, Juri G.

    2008-05-13

    Objectives. The overall objective of this application is to develop novel technologies for non-invasive imaging of adoptive stem cell-based therapies with positron emission tomography (PET) that would be applicable to human patients. To achieve this objective, stem cells will be genetically labeled with a PET-reporter gene and repetitively imaged to assess their distribution, migration, differentiation, and persistence using a radiolabeled reporter probe. This new imaging technology will be tested in adoptive progenitor cell-based therapy models in animals, including: delivery pro-apoptotic genes to tumors, and T-cell reconstitution for immunostimulatory therapy during allogeneic bone marrow progenitor cell transplantation. Technical and Scientific Merits. Non-invasive whole body imaging would significantly aid in the development and clinical implementation of various adoptive progenitor cell-based therapies by providing the means for non-invasive monitoring of the fate of injected progenitor cells over a long period of observation. The proposed imaging approaches could help to address several questions related to stem cell migration and homing, their long-term viability, and their subsequent differentiation. The ability to image these processes non-invasively in 3D and repetitively over a long period of time is very important and will help the development and clinical application of various strategies to control and direct stem cell migration and differentiation. Approach to accomplish the work. Stem cells will be genetically with a reporter gene which will allow for repetitive non-invasive “tracking” of the migration and localization of genetically labeled stem cells and their progeny. This is a radically new approach that is being developed for future human applications and should allow for a long term (many years) repetitive imaging of the fate of tissues that develop from the transplanted stem cells. Why the approach is appropriate. The novel approach to

  15. PET imaging of adoptive progenitor cell therapies

    International Nuclear Information System (INIS)

    The overall objective of this application is to develop novel technologies for non-invasive imaging of adoptive stem cell-based therapies with positron emission tomography (PET) that would be applicable to human patients. To achieve this objective, stem cells will be genetically labeled with a PET-reporter gene and repetitively imaged to assess their distribution, migration, differentiation, and persistence using a radiolabeled reporter probe. This new imaging technology will be tested in adoptive progenitor cell-based therapy models in animals, including: delivery pro-apoptotic genes to tumors, and T-cell reconstitution for immunostimulatory therapy during allogeneic bone marrow progenitor cell transplantation. Technical and Scientific Merits. Non-invasive whole body imaging would significantly aid in the development and clinical implementation of various adoptive progenitor cell-based therapies by providing the means for non-invasive monitoring of the fate of injected progenitor cells over a long period of observation. The proposed imaging approaches could help to address several questions related to stem cell migration and homing, their long-term viability, and their subsequent differentiation. The ability to image these processes non-invasively in 3D and repetitively over a long period of time is very important and will help the development and clinical application of various strategies to control and direct stem cell migration and differentiation. Approach to accomplish the work. Stem cells will be genetically with a reporter gene which will allow for repetitive non-invasive 'tracking' of the migration and localization of genetically labeled stem cells and their progeny. This is a radically new approach that is being developed for future human applications and should allow for a long term (many years) repetitive imaging of the fate of tissues that develop from the transplanted stem cells. Why the approach is appropriate. The novel approach to stem cell imaging

  16. Performance Evaluation of a Small-Animal PET/CT System

    OpenAIRE

    Dahle, Tordis Johnsen

    2014-01-01

    This master project is the first vendor-independent performance evaluation of the new nanoScan PET/CT system at the University of Bergen. A comprehensive performance evaluation of a novel scanner is very important, particularly when quantitative assessments of images are required. The nanoScan PET/CT system is a fully integrated small-animal PET/CT system. An abbreviated performance evaluation of the CT subsystem was done, which included a Hounsfield quality check, a comparison of reconstr...

  17. Quantitative PET imaging with the 3T MR-BrainPET

    International Nuclear Information System (INIS)

    The new hybrid imaging technology of MR-PET allows for simultaneous acquisition of versatile MRI contrasts and the quantitative metabolic imaging with PET. In order to achieve the quantification of PET images with minimal residual error the application of several corrections is crucial. In this work we present our results on quantification with the 3T MR BrainPET scanner

  18. Quantitative Techniques in PET-CT Imaging

    NARCIS (Netherlands)

    Basu, Sandip; Zaidi, Habib; Holm, Soren; Alavi, Abass

    2011-01-01

    The appearance of hybrid PET/CT scanners has made quantitative whole body scanning of radioactive tracers feasible. This paper deals with the novel concepts for assessing global organ function and disease activity based on combined functional (PET) and structural (CT or MR) imaging techniques, their

  19. Progress of PET imaging in Schizophrenia

    International Nuclear Information System (INIS)

    PET is an important functional neuroimaging technique that can be used to assessment of cerebral metabolic activity and blood flow and identifies the distribution of important neurotransmitters in the human brain. Compared with other conventional imaging techniques, PET enables regional cerebral glucose metabolism, blood flow, dopaminergic and serotonergic receptor function to be assessed qualitatively and quantitatively. In recent years, PET increasingly being used greatly to advance our understanding of the neurobiology and pathophysiology of schizophrenia. This review focuses on the use of PET tracers in identifying regional brain abnormalities and regions associated with cognitive functioning in schizophrenia. (authors)

  20. FDG-PET imaging in hematological malignancies.

    Science.gov (United States)

    Valls, L; Badve, C; Avril, S; Herrmann, K; Faulhaber, P; O'Donnell, J; Avril, N

    2016-07-01

    The majority of aggressive lymphomas is characterized by an up regulated glycolytic activity, which enables the visualization by F-18 FDG-PET/CT. One-stop hybrid FDG-PET/CT combines the functional and morphologic information, outperforming both, CT and FDG-PET as separate imaging modalities. This has resulted in several recommendations using FDG-PET/CT for staging, restaging, monitoring during therapy, and assessment of treatment response as well as identification of malignant transformation. FDG-PET/CT may obviate the need for a bone marrow biopsy in patients with Hodgkin's lymphoma and diffuse large B cell lymphoma. FDG-PET/CT response assessment is recommended for FDG-avid lymphomas, whereas CT-based response evaluation remains important in lymphomas with low or variable FDG avidity. The treatment induced change in metabolic activity allows for assessment of response after completion of therapy as well as prediction of outcome early during therapy. The five-point scale Deauville Criteria allows the assessment of treatment response based on visual FDG-PET analysis. Although the use of FDG-PET/CT for prediction of therapeutic response is promising it should only be conducted in the context of clinical trials. Surveillance FDG-PET/CT after complete remission is discouraged due to the relative high number of false-positive findings, which in turn may result in further unnecessary investigations. Future directions include the use of new PET tracers such as F-18 fluorothymidine (FLT), a surrogate biomarker of cellular proliferation and Ga-68 CXCR4, a chemokine receptor imaging biomarker as well as innovative digital PET/CT and PET/MRI techniques. PMID:27090170

  1. Small animal simultaneous PET/MRI: initial experiences in a 9.4 T microMRI

    Science.gov (United States)

    Harsha Maramraju, Sri; Smith, S. David; Junnarkar, Sachin S.; Schulz, Daniela; Stoll, Sean; Ravindranath, Bosky; Purschke, Martin L.; Rescia, Sergio; Southekal, Sudeepti; Pratte, Jean-François; Vaska, Paul; Woody, Craig L.; Schlyer, David J.

    2011-04-01

    We developed a non-magnetic positron-emission tomography (PET) device based on the rat conscious animal PET that operates in a small-animal magnetic resonance imaging (MRI) scanner, thereby enabling us to carry out simultaneous PET/MRI studies. The PET detector comprises 12 detector blocks, each being a 4 × 8 array of lutetium oxyorthosilicate crystals (2.22 × 2.22 × 5 mm3) coupled to a matching non-magnetic avalanche photodiode array. The detector blocks, housed in a plastic case, form a 38 mm inner diameter ring with an 18 mm axial extent. Custom-built MRI coils fit inside the positron-emission tomography (PET) device, operating in transceiver mode. The PET insert is integrated with a Bruker 9.4 T 210 mm clear-bore diameter MRI scanner. We acquired simultaneous PET/MR images of phantoms, of in vivo rat brain, and of cardiac-gated mouse heart using [11C]raclopride and 2-deoxy-2-[18F]fluoro-d-glucose PET radiotracers. There was minor interference between the PET electronics and the MRI during simultaneous operation, and small effects on the signal-to-noise ratio in the MR images in the presence of the PET, but no noticeable visual artifacts. Gradient echo and high-duty-cycle spin echo radio frequency (RF) pulses resulted in a 7% and a 28% loss in PET counts, respectively, due to high PET counts during the RF pulses that had to be gated out. The calibration of the activity concentration of PET data during MR pulsing is reproducible within less than 6%. Our initial results demonstrate the feasibility of performing simultaneous PET and MRI studies in adult rats and mice using the same PET insert in a small-bore 9.4 T MRI.

  2. PET: functional imaging applications in oncology

    International Nuclear Information System (INIS)

    PET imaging plays an important role in the diagnosis, staging and management of tumors. At present, its principal application is in lung cancer, but interest in other applications is growing rapidly. (orig.)

  3. Positron range in PET imaging: an alternative approach for assessing and correcting the blurring

    DEFF Research Database (Denmark)

    Jødal, Lars; Le Loirec, Cindy; Champion, Christophe

    2012-01-01

    Background: Positron range impairs resolution in PET imaging, especially for high-energy emitters and for small-animal PET. De-blurring in image reconstruction is possible if the blurring distribution is known. Further, the percentage of annihilation events within a given distance from the point ...

  4. In vivo imaging and characterization of [18F]DPA-714, a potential new TSPO ligand, in mouse brain and peripheral tissues using small-animal PET

    International Nuclear Information System (INIS)

    Introduction: The translocator protein 18 kDa (TSPO), a biochemical marker of neuroinflammation, is highly expressed in the brain activated microglia and it is also expressed by peripheral inflammatory cells and normal peripheral tissues. Thus, development of radioligands for the TSPO may contribute to further understanding the in vivo TSPO function in central and peripheral inflammatory processes and other pathologies. Here, we report the biodistribution, the specific binding and the radiometabolites of [18F]DPA-714, a promising fluorinated PET radiotracer, in normal mice using a microPET/CT scanner. Methods: The in vivo biodistribution and kinetics of [18F]DPA-714 were measured in mice brain and peripheral tissues. Specific binding to TSPO sites was assessed using pharmacological competitive studies by means of saturation experiments performed by i.v. injection of 1 mg/kg of unlabeled DPA-714 or 3 mg/kg of unlabeled PK11195. A region of interest analysis was performed to generate time-activity curves in the brain, heart, lung, kidney, spleen and liver. Metabolites assay was performed in the plasma and peripheral organs by radio-HPLC. Results: [18F]DPA-714 reached high concentration in lung, heart, kidney and spleen, tissues well known to be rich in TSPO sites. [18F]DPA-714 kinetics were faster in the lung and slower in the kidney. Pre-injection of unlabeled DPA-714 or PK11195 inhibited about 80% of [18F]DPA-714 uptake in the lung and heart (p < 0.0005). The percentage of inhibition in the kidney was lower and achieved at later times only with DPA-714 (p < 0.05) but not with PK11195. Sixty minutes after radiotracer injection only unmetabolized radioligand was found in the brain, lung, heart and spleen. Conclusion: These results suggest that [18F]DPA-714 is a suitable PET ligand for imaging in mice brain and peripheral tissues since it binds with high specificity TSPO binding sites and it is almost unchanged at 60 minutes after radiotracer injection in the brain

  5. Evaluation of [11C]SA5845 and [11C]SA4503 for imaging of sigma receptors in tumors by animal PET

    International Nuclear Information System (INIS)

    Sigma receptors are expressed in a wide variety of tumor cell lines, and are expressed in proliferating cells. A radioligand for the visualization of sigma receptors could be useful for selective detection of primary tumors and their metastases, and for non-invasive assessment of tumor proliferative status. To this end we evaluated two sigma receptor ligands, [11C]SA5845 and [11C]SA4503. In an in vitro study, AH109A hepatoma showed moderate densities of sigma1 and sigma2 receptors, and VX-2 carcinoma showed a high density of sigma2 receptors: Bmax (fmol/mg protein) for sigma1 vs. sigma2, 1,700 vs. 1,200 for AH109A hepatoma and 800 vs. 10,000 for VX-2 carcinoma. In a cell growth assay in vitro, neither SA5845 nor SA4503 (11C]SA5845 and [11C]SA4503 in AH109A tissues was accumulated over the first 60 minutes; however, the uptake of both tracers increased by co-injection with haloperidol as a sigma receptor ligand. On the other hand, in the PET studies of rabbits, the uptake of [11C]SA5845 in the VX-2 carcinoma was relatively higher than that of [11C]SA4503, because of a much higher density of sigma2 receptors compared to sigma1 receptors in the VX-2 tissue, and the uptake of both tracers in the VX-2 tissue was decreased by carrier-loading and pre-treatment with haloperidol ([11C]SA5845, 53% and 26%, respectively; [11C]SA4503, 41% and 22%, respectively at 30 minutes after injection). Therefore, [11C]SA5845 and [11C]SA4503 may be potential ligands for PET imaging of sigma receptor-rich tumors. (author)

  6. Molecular Characterization of Pneumococcal Isolates from Pets and Laboratory Animals

    OpenAIRE

    Mark van der Linden; Adnan Al-Lahham; Werner Nicklas; Ralf René Reinert

    2009-01-01

    BACKGROUND: Between 1986 and 2008 Streptococcus pneumoniae was isolated from 41 pets/zoo animals (guinea pigs (n = 17), cats (n = 12), horses (n = 4), dogs (n = 3), dolphins (n = 2), rat (n = 2), gorilla (n = 1)) treated in medical veterinary laboratories and zoos, and 44 laboratory animals (mastomys (multimammate mice; n = 32), mice (n = 6), rats (n = 4), guinea pigs (n = 2)) during routine health monitoring in an animal facility. S. pneumoniae was isolated from nose, lung and respiratory tr...

  7. Positron range in PET imaging: an alternative approach for assessing and correcting the blurring

    OpenAIRE

    Jødal, Lars; Le Loirec, Cindy; Champion, Christophe

    2012-01-01

    Background: Positron range impairs resolution in PET imaging, especially for high-energy emitters and for small-animal PET. De-blurring in image reconstruction is possible if the blurring distribution is known. Further, the percentage of annihilation events within a given distance from the point of positron emission is relevant for assessing statistical noise. Aims: The paper aims to determine positron range distribution relevant for blurring for seven medically relevant PET isotopes, 18F, 11...

  8. Ga-68-DOTATOC: Feasibility of high throughput screening by small animal PET using a clinical high-resolution PET/CT scanner

    International Nuclear Information System (INIS)

    As radio peptide tracers have been developed in recent years for the high sensitive detection of neuroendocrine tumors, still the broad application of other peptides to breast and prostate cancer is missing. A rapid screening of new peptides can, in theory, be based on in vivo screening in animals by PET/CT. To test this hypothesis and to asses the minimum screening time needed per animal, we used the application of Ga-68-DOTATOC PET/CT in rats as test system. The Ga-68-DOTATOC yields in a hot spot imaging with minimal background. To delineate liver and spleen, we performed PET/CT of 10 animals on a SIEMENS Biograph 16 LSO HIGHREZ after intravenous injection of 1.5 MBq Ga-68-DOTATOC per animal. Animals were mounted in an '18 slot' holding device and scanned for a single-bed position. The emission times for the PET scan was varied from 1 to 20 min. The images were assessed first for 'PET only' and afterwards in PET/CT fusion mode. The detection of the two organs was good at emission times down to 1 min in PET/CT fusion mode. In the 'PET only' scans, the liver was clearly to be identified down to 1 min emission in all animals. But the spleen could only be delineated only by 1 min of emission in the PET/CT-fusion mode. In conclusion the screening of 'hot spot' enriching peptides is feasible. 'PET only' is in terms of delineation of small organs by far inferior to PET/CT fusion. If animal tumors are above a diameter of 10 mm small, animal PET/CT using clinical high resolution scanners will enable rapid screening. Even the determination of bio-distributions becomes feasible by using list mode tools. The time for the whole survey of 18 animals including anesthesia, preparation and mounting was approximately 20 min. By use of several holding devices mounted simultaneously, a survey time of less than 1 h for 180 animals can be expected

  9. The significant human-animal bond: Pets with cancer

    Energy Technology Data Exchange (ETDEWEB)

    Weller, R.E.

    1994-03-01

    Veterinarians have responsibilities to both the animal and its owner. In the past several years there has been an increased awareness and concern about human-animal bonds. As a result, we have begun to appreciate the nature, strength, and significance of bonds that develop between humans and companion animals. It is typical for a pet to be perceived as and treated as a member of the family and as a result, animals provide special and beneficial relationships for many years. It is partly because of this role of the pet in promoting human health and happiness that we as veterinarians have an obligation to assist both owner and animal. The mark of the good practitioner concerns not only the ability to diagnose and treat accurately, but also the ability to show understanding and compassionate judgement.

  10. Advances in Small Animal Imaging Systems

    International Nuclear Information System (INIS)

    The rapid growth in genetics and molecular biology combined with the development of techniques for genetically engineering small animals has led to an increased interest in in vivo laboratory animal imaging during the past few years. For this purpose, new instrumentation, data acquisition strategies, and image processing and reconstruction techniques are being developed, researched and evaluated. The aim of this article is to give a short overview of the state of the art technologies for high resolution and high sensitivity molecular imaging techniques, primarily positron emission tomography (PET) and single photon emission computed tomography (SPECT). The basic needs of small animal imaging will be described. The evolution in instrumentation in the past two decades, as well as the commercially available systems will be overviewed. Finally, the new trends in detector technology and preliminary results from challenging applications will be presented. For more details a number of references are provided

  11. Animal Images and Metaphors in Animal Farm

    Directory of Open Access Journals (Sweden)

    Ping Sun

    2015-05-01

    Full Text Available In literary works animal images are frequently used as the “source domain” of a metaphor to disclose the natures of the “target domain”, human beings. This is called “cross-domain mapping” or “conceptual metaphor” in cognitive linguistics, which is based on the similar qualities between animals and human beings. Thus the apparent descriptions of the animals are really the deep revelations of the human beings. Animal Farm is one exemplary product of this special expressing way. Diversified animal images are intelligently used by George Orwell to represent the people, so all the characters are animals in appearance, but humans in nature. Starting from the animal images and then the conceptual metaphors, readers can perceive a fresh understanding of this classical book. In this novel, three conceptual metaphors are identified and the special findings can be illustrated as the following: Firstly, the whole story of the animals represents the history and politics of the Soviet Union. Secondly, the pigs symbolize the authorities of the society. Thirdly, the names of the characters in the novel reveal their identities.

  12. Animal Images and Metaphors in Animal Farm

    OpenAIRE

    Ping Sun

    2015-01-01

    In literary works animal images are frequently used as the “source domain” of a metaphor to disclose the natures of the “target domain”, human beings. This is called “cross-domain mapping” or “conceptual metaphor” in cognitive linguistics, which is based on the similar qualities between animals and human beings. Thus the apparent descriptions of the animals are really the deep revelations of the human beings. Animal Farm is one exemplary product of this special expressing way. Diversified ani...

  13. Denoising of high resolution small animal 3D PET data using the non-subsampled Haar wavelet transform

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa Domínguez, Humberto de Jesús, E-mail: hochoa@uacj.mx [Departamento de Ingeniería Eléctrica y computación, Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chih. (Mexico); Máynez, Leticia O. [Departamento de Ingeniería Eléctrica y computación, Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chih. (Mexico); Vergara Villegas, Osslan O. [Departamento de Ingeniería Industrial, Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chih. (Mexico); Mederos, Boris; Mejía, José M.; Cruz Sánchez, Vianey G. [Departamento de Ingeniería Eléctrica y computación, Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chih. (Mexico)

    2015-06-01

    PET allows functional imaging of the living tissue. However, one of the most serious technical problems affecting the reconstructed data is the noise, particularly in images of small animals. In this paper, a method for high-resolution small animal 3D PET data is proposed with the aim to reduce the noise and preserve details. The method is based on the estimation of the non-subsampled Haar wavelet coefficients by using a linear estimator. The procedure is applied to the volumetric images, reconstructed without correction factors (plane reconstruction). Results show that the method preserves the structures and drastically reduces the noise that contaminates the image.

  14. Denoising of high resolution small animal 3D PET data using the non-subsampled Haar wavelet transform

    International Nuclear Information System (INIS)

    PET allows functional imaging of the living tissue. However, one of the most serious technical problems affecting the reconstructed data is the noise, particularly in images of small animals. In this paper, a method for high-resolution small animal 3D PET data is proposed with the aim to reduce the noise and preserve details. The method is based on the estimation of the non-subsampled Haar wavelet coefficients by using a linear estimator. The procedure is applied to the volumetric images, reconstructed without correction factors (plane reconstruction). Results show that the method preserves the structures and drastically reduces the noise that contaminates the image

  15. PET imaging of the autonomic myocardial function: methods and interpretation

    OpenAIRE

    Noordzij, Walter; Slart, Riemer H.J.A.

    2015-01-01

    Cardiac positron emission tomography (PET) is mainly applied in myocardial perfusion and viability detection. Noninvasive imaging of myocardial innervation using PET is a valuable additional methodology in cardiac imaging. Novel methods and different PET ligands have been developed to measure presynaptic and postsynaptic function of the cardiac neuronal system. Obtained PET data can be analysed quantitatively or interpreted qualitatively. Thus far, PET is not a widely used clinical applicatio...

  16. Monte Carlo based performance assessment of different animal PET architectures using pixellated CZT detectors

    International Nuclear Information System (INIS)

    The majority of present position emission tomography (PET) animal systems are based on the coupling of high-density scintillators and light detectors. A disadvantage of these detector configurations is the compromise between image resolution, sensitivity and energy resolution. In addition, current combined imaging devices are based on simply placing back-to-back and in axial alignment different apparatus without any significant level of software or hardware integration. The use of semiconductor CdZnTe (CZT) detectors is a promising alternative to scintillators for gamma-ray imaging systems. At the same time CZT detectors have the potential properties necessary for the construction of a truly integrated imaging device (PET/SPECT/CT). The aims of this study was to assess the performance of different small animal PET scanner architectures based on CZT pixellated detectors and compare their performance with that of state of the art existing PET animal scanners. Different scanner architectures were modelled using GATE (Geant4 Application for Tomographic Emission). Particular scanner design characteristics included an overall cylindrical scanner format of 8 and 24 cm in axial and transaxial field of view, respectively, and a temporal coincidence window of 8 ns. Different individual detector modules were investigated, considering pixel pitch down to 0.625 mm and detector thickness from 1 to 5 mm. Modified NEMA NU2-2001 protocols were used in order to simulate performance based on mouse, rat and monkey imaging conditions. These protocols allowed us to directly compare the performance of the proposed geometries with the latest generation of current small animal systems. Results attained demonstrate the potential for higher NECR with CZT based scanners in comparison to scintillator based animal systems

  17. Monte Carlo based performance assessment of different animal PET architectures using pixellated CZT detectors

    Science.gov (United States)

    Visvikis, D.; Lefevre, T.; Lamare, F.; Kontaxakis, G.; Santos, A.; Darambara, D.

    2006-12-01

    The majority of present position emission tomography (PET) animal systems are based on the coupling of high-density scintillators and light detectors. A disadvantage of these detector configurations is the compromise between image resolution, sensitivity and energy resolution. In addition, current combined imaging devices are based on simply placing back-to-back and in axial alignment different apparatus without any significant level of software or hardware integration. The use of semiconductor CdZnTe (CZT) detectors is a promising alternative to scintillators for gamma-ray imaging systems. At the same time CZT detectors have the potential properties necessary for the construction of a truly integrated imaging device (PET/SPECT/CT). The aims of this study was to assess the performance of different small animal PET scanner architectures based on CZT pixellated detectors and compare their performance with that of state of the art existing PET animal scanners. Different scanner architectures were modelled using GATE (Geant4 Application for Tomographic Emission). Particular scanner design characteristics included an overall cylindrical scanner format of 8 and 24 cm in axial and transaxial field of view, respectively, and a temporal coincidence window of 8 ns. Different individual detector modules were investigated, considering pixel pitch down to 0.625 mm and detector thickness from 1 to 5 mm. Modified NEMA NU2-2001 protocols were used in order to simulate performance based on mouse, rat and monkey imaging conditions. These protocols allowed us to directly compare the performance of the proposed geometries with the latest generation of current small animal systems. Results attained demonstrate the potential for higher NECR with CZT based scanners in comparison to scintillator based animal systems.

  18. Monte Carlo based performance assessment of different animal PET architectures using pixellated CZT detectors

    Energy Technology Data Exchange (ETDEWEB)

    Visvikis, D. [INSERM U650, LaTIM, University Hospital Medical School, F-29609 Brest (France)]. E-mail: Visvikis.Dimitris@univ-brest.fr; Lefevre, T. [INSERM U650, LaTIM, University Hospital Medical School, F-29609 Brest (France); Lamare, F. [INSERM U650, LaTIM, University Hospital Medical School, F-29609 Brest (France); Kontaxakis, G. [ETSI Telecomunicacion Universidad Politecnica de Madrid, Ciudad Universitaria, s/n 28040, Madrid (Spain); Santos, A. [ETSI Telecomunicacion Universidad Politecnica de Madrid, Ciudad Universitaria, s/n 28040, Madrid (Spain); Darambara, D. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford (United Kingdom)

    2006-12-20

    The majority of present position emission tomography (PET) animal systems are based on the coupling of high-density scintillators and light detectors. A disadvantage of these detector configurations is the compromise between image resolution, sensitivity and energy resolution. In addition, current combined imaging devices are based on simply placing back-to-back and in axial alignment different apparatus without any significant level of software or hardware integration. The use of semiconductor CdZnTe (CZT) detectors is a promising alternative to scintillators for gamma-ray imaging systems. At the same time CZT detectors have the potential properties necessary for the construction of a truly integrated imaging device (PET/SPECT/CT). The aims of this study was to assess the performance of different small animal PET scanner architectures based on CZT pixellated detectors and compare their performance with that of state of the art existing PET animal scanners. Different scanner architectures were modelled using GATE (Geant4 Application for Tomographic Emission). Particular scanner design characteristics included an overall cylindrical scanner format of 8 and 24 cm in axial and transaxial field of view, respectively, and a temporal coincidence window of 8 ns. Different individual detector modules were investigated, considering pixel pitch down to 0.625 mm and detector thickness from 1 to 5 mm. Modified NEMA NU2-2001 protocols were used in order to simulate performance based on mouse, rat and monkey imaging conditions. These protocols allowed us to directly compare the performance of the proposed geometries with the latest generation of current small animal systems. Results attained demonstrate the potential for higher NECR with CZT based scanners in comparison to scintillator based animal systems.

  19. Performance characteristics of microPET R4 scanner for small animal

    International Nuclear Information System (INIS)

    Dedicated animal PET is useful equipment for the study of new PET tracer. Recently microPET R4 was installed in the Korea institute of radiology and medical science. In this study, we measured the characteristics of scanner. Resolution was measured using a line source (F-18:65 μ Ci, inner diameter: 0.5 mm). The line source was put in the axial direction and was moved from the center of field of view to outside with 1 mm interval. PET images were reconstructed using a filtered back-projection and ordered subset expectation maximization. Line source (16.5 μ Ci, 78 mm) was put on the center of axial direction to measure the sensitivity when the deadtime was under 1%. Images were acquired during 4 minutes respectively from center to 39 mm outward. Delayed count was subtracted from total count and then decay was corrected for the calculation of sensitivity. Noise equivalent count ratio and scatter fraction were calculated using cylindrical phantom. Spatial resolution of reconstructed image using filtered back-projection was 1.86 mm(radial), 1.95 mm(tangential), 1.95 mm(axial) in the center of field of view, and 2.54 mm, 2.8 mm, 1.61 mm in 2 cm away from the center respectively. Sensitivity was 2.36% at the center of transaxial field of view. Scatter fraction was 20%. Maximal noise equivalent count ratio was 66.4 kcps at 242 kBq/mL. Small animal images were acquired for confirmation of performance. Performance characteristics of microPET R4 were similar with reported value. So this will be a useful tool for small animal imaging

  20. PET imaging for evaluating tumor angiogenesis

    International Nuclear Information System (INIS)

    Angiogenesis, a main characteristic in tumors, plays an important role in tumor growth and metastasis, which provides a new strategy for tumor treatment. By marking angiogenesis-related receptors, polypeptides, kinases or extracellular matrix proteins as high affinity molecular probes, PET imaging can noninvasively display integrin, VEGF/VEGFR, matrix metalloproteinases (MMPs) and closely monitor tumor angiogenesis and vascular-targeted treatments on the molecular level. In this paper, research progress and future development of PET imaging for evaluating tumor angiogenesis are reviewed. (authors)

  1. A small animal pet prototype with sub-millimetre spatial resolution based on tRPCs

    OpenAIRE

    Blanco Castro, Alberto

    2012-01-01

    The aim of this thesis is to explore the possibility of building a Positron Emission Tomography (PET) system with sub-millimetre spatial resolution and absence of parallax error based on timing Resistive Plate Chambers (tRPC), to be used in the imaging of small animals. An RPC-PET prototype has been built consisting in two detector heads. Each head is built from sixteen independent metal-glass RPCs with a gas gap of 0.300 mm working on avalanche mode in the standard mixture. The cha...

  2. Automated analysis of small animal PET studies through deformable registration to an atlas

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, Daniel F. [Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva 4 (Switzerland); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva 4 (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland); University of Groningen, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands)

    2012-11-15

    This work aims to develop a methodology for automated atlas-guided analysis of small animal positron emission tomography (PET) data through deformable registration to an anatomical mouse model. A non-rigid registration technique is used to put into correspondence relevant anatomical regions of rodent CT images from combined PET/CT studies to corresponding CT images of the Digimouse anatomical mouse model. The latter provides a pre-segmented atlas consisting of 21 anatomical regions suitable for automated quantitative analysis. Image registration is performed using a package based on the Insight Toolkit allowing the implementation of various image registration algorithms. The optimal parameters obtained for deformable registration were applied to simulated and experimental mouse PET/CT studies. The accuracy of the image registration procedure was assessed by segmenting mouse CT images into seven regions: brain, lungs, heart, kidneys, bladder, skeleton and the rest of the body. This was accomplished prior to image registration using a semi-automated algorithm. Each mouse segmentation was transformed using the parameters obtained during CT to CT image registration. The resulting segmentation was compared with the original Digimouse atlas to quantify image registration accuracy using established metrics such as the Dice coefficient and Hausdorff distance. PET images were then transformed using the same technique and automated quantitative analysis of tracer uptake performed. The Dice coefficient and Hausdorff distance show fair to excellent agreement and a mean registration mismatch distance of about 6 mm. The results demonstrate good quantification accuracy in most of the regions, especially the brain, but not in the bladder, as expected. Normalized mean activity estimates were preserved between the reference and automated quantification techniques with relative errors below 10 % in most of the organs considered. The proposed automated quantification technique is

  3. Automated analysis of small animal PET studies through deformable registration to an atlas

    International Nuclear Information System (INIS)

    This work aims to develop a methodology for automated atlas-guided analysis of small animal positron emission tomography (PET) data through deformable registration to an anatomical mouse model. A non-rigid registration technique is used to put into correspondence relevant anatomical regions of rodent CT images from combined PET/CT studies to corresponding CT images of the Digimouse anatomical mouse model. The latter provides a pre-segmented atlas consisting of 21 anatomical regions suitable for automated quantitative analysis. Image registration is performed using a package based on the Insight Toolkit allowing the implementation of various image registration algorithms. The optimal parameters obtained for deformable registration were applied to simulated and experimental mouse PET/CT studies. The accuracy of the image registration procedure was assessed by segmenting mouse CT images into seven regions: brain, lungs, heart, kidneys, bladder, skeleton and the rest of the body. This was accomplished prior to image registration using a semi-automated algorithm. Each mouse segmentation was transformed using the parameters obtained during CT to CT image registration. The resulting segmentation was compared with the original Digimouse atlas to quantify image registration accuracy using established metrics such as the Dice coefficient and Hausdorff distance. PET images were then transformed using the same technique and automated quantitative analysis of tracer uptake performed. The Dice coefficient and Hausdorff distance show fair to excellent agreement and a mean registration mismatch distance of about 6 mm. The results demonstrate good quantification accuracy in most of the regions, especially the brain, but not in the bladder, as expected. Normalized mean activity estimates were preserved between the reference and automated quantification techniques with relative errors below 10 % in most of the organs considered. The proposed automated quantification technique is

  4. Animal imaging studies of potential brain damage

    Science.gov (United States)

    Gatley, S. J.; Vazquez, M. E.; Rice, O.

    To date, animal studies have not been able to predict the likelihood of problems in human neurological health due to HZE particle exposure during space missions outside the Earth's magnetosphere. In ongoing studies in mice, we have demonstrated that cocaine stimulated locomotor activity is reduced by a moderate dose (120 cGy) of 1 GeV 56Fe particles. We postulate that imaging experiments in animals may provide more sensitive and earlier indicators of damage due to HZE particles than behavioral tests. Since the small size of the mouse brain is not well suited to the spatial resolution offered by microPET, we are now repeating some of our studies in a rat model. We anticipate that this will enable us to identify imaging correlates of behavioral endpoints. A specific hypothesis of our studies is that changes in the metabolic rate for glucose in striatum of animals will be correlated with alterations in locomotor activity. We will also evaluate whether the neuroprotective drug L-deprenyl reduces the effect of radiation on locomotor activity. In addition, we will conduct microPET studies of brain monoamine oxidase A and monoamine oxidase B in rats before and at various times after irradiation with HZE particles. The hypothesis is that monoamine oxidase A, which is located in nerve terminals, will be unchanged or decreased after irradiation, while monoamine oxidase B, which is located in glial cells, will be increased after irradiation. Neurochemical effects that could be measured using PET could in principle be applied in astronauts, in terms of detecting and monitoring subtle neurological damage that might have occurred during long space missions. More speculative uses of PET are in screening candidates for prolonged space missions (for example, for adequate reserve in critical brain circuits) and in optimizing medications to treat impairments after missions.

  5. The research on detector sensitivity of full-coverage animal PET system

    International Nuclear Information System (INIS)

    In order to improve detector sensitivity of small animal PET system and increase geometry angle coverage rate of detector, a full-coverage animal PET system design is proposed, in which two square detectors are added to the original circular PET scanner's both ends. There is a hole in the middle of each of the two square detectors. To investigate the detector sensitivity performance of the new system, GATE was used to build system model and simulation was performed with three different types of radioactive sources which is point, plane and volume sources. The simulation results demonstrate that the change to the detector structure effectively increase the detector sensitivity, and the number of line of responses (LOR) is doubled more than before which will potentially benefit image reconstruction; meanwhile the simulation results of point and plane radioactive sources show that the proposed full-coverage arrangement of detectors improves the uniformity of sensitivity in the FOV, however the hole on the board detector weakens the improvement of detector sensitivity, especially to the radioactive source which is put on the edge of the FOV. Full-coverage animal PET system as proposed can improve detector sensitivity and image quality. (authors)

  6. LOR-interleaving image reconstruction for PET imaging with fractional-crystal collimation

    Science.gov (United States)

    Li, Yusheng; Matej, Samuel; Karp, Joel S.; Metzler, Scott D.

    2015-01-01

    Positron emission tomography (PET) has become an important modality in medical and molecular imaging. However, in most PET applications, the resolution is still mainly limited by the physical crystal sizes or the detector’s intrinsic spatial resolution. To achieve images with better spatial resolution in a central region of interest (ROI), we have previously proposed using collimation in PET scanners. The collimator is designed to partially mask detector crystals to detect lines of response (LORs) within fractional crystals. A sequence of collimator-encoded LORs is measured with different collimation configurations. This novel collimated scanner geometry makes the reconstruction problem challenging, as both detector and collimator effects need to be modeled to reconstruct high-resolution images from collimated LORs. In this paper, we present a LOR-interleaving (LORI) algorithm, which incorporates these effects and has the advantage of reusing existing reconstruction software, to reconstruct high-resolution images for PET with fractional-crystal collimation. We also develop a 3D ray-tracing model incorporating both the collimator and crystal penetration for simulations and reconstructions of the collimated PET. By registering the collimator-encoded LORs with the collimator configurations, high-resolution LORs are restored based on the modeled transfer matrices using the non-negative least-squares method and EM algorithm. The resolution-enhanced images are then reconstructed from the high-resolution LORs using the MLEM or OSEM algorithm. For validation, we applied the LORI method to a small-animal PET scanner, A-PET, with a specially designed collimator. We demonstrate through simulated reconstructions with a hot-rod phantom and MOBY phantom that the LORI reconstructions can substantially improve spatial resolution and quantification compared to the uncollimated reconstructions. The LORI algorithm is crucial to improve overall image quality of collimated PET, which

  7. LOR-interleaving image reconstruction for PET imaging with fractional-crystal collimation

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) has become an important modality in medical and molecular imaging. However, in most PET applications, the resolution is still mainly limited by the physical crystal sizes or the detector’s intrinsic spatial resolution. To achieve images with better spatial resolution in a central region of interest (ROI), we have previously proposed using collimation in PET scanners. The collimator is designed to partially mask detector crystals to detect lines of response (LORs) within fractional crystals. A sequence of collimator-encoded LORs is measured with different collimation configurations. This novel collimated scanner geometry makes the reconstruction problem challenging, as both detector and collimator effects need to be modeled to reconstruct high-resolution images from collimated LORs. In this paper, we present a LOR-interleaving (LORI) algorithm, which incorporates these effects and has the advantage of reusing existing reconstruction software, to reconstruct high-resolution images for PET with fractional-crystal collimation. We also develop a 3D ray-tracing model incorporating both the collimator and crystal penetration for simulations and reconstructions of the collimated PET. By registering the collimator-encoded LORs with the collimator configurations, high-resolution LORs are restored based on the modeled transfer matrices using the non-negative least-squares method and EM algorithm. The resolution-enhanced images are then reconstructed from the high-resolution LORs using the MLEM or OSEM algorithm. For validation, we applied the LORI method to a small-animal PET scanner, A-PET, with a specially designed collimator. We demonstrate through simulated reconstructions with a hot-rod phantom and MOBY phantom that the LORI reconstructions can substantially improve spatial resolution and quantification compared to the uncollimated reconstructions. The LORI algorithm is crucial to improve overall image quality of collimated PET, which

  8. PET imaging in patients with Modic changes

    Energy Technology Data Exchange (ETDEWEB)

    Albert, H.B.; Manniche, C. [Univ. of Southern Denmark, Funen (Denmark). Back Research Centre; Petersen, H.; Hoeilund-Carlsen, P.F. [Odense University Hospital, Univ. of Southern Denmark (Denmark). Dept. of Nuclear Medicine

    2009-07-01

    The aim of this study was via PET imaging to reveal if any highly metabolic processes were occurring in Modic changes type 1 and/or in the adjacent discs. Modic changes (MC) are signal changes in the vertebral endplate and body visualised by magnetic resonance imaging (MRI). MC are strongly associated with low back pain (LBP). MC type 1 appear to be inflammation on MRI, and histological and biochemical findings make it highly likely that an inflammation is present. Though MC is painful no known treatment is available, and it is unknown which entities affect the progress or regress of MC. The changes observed on MRI are slow and take months to develop, but faster changes in the metabolism might provide a platform for monitoring patients. Patients from The Back Centre Funen, with low back pain in the area of L1 to S1, MC type 1 in L1 to L5, and a previous herniated lumbar disc. All patients had a PET scan using FDG ({sup 18}F-fluorodeoxyglucose) as tracer. Included in the study were 11 patients, 4 women and 7 men, mean age 48.1 year (range 20-65). All MC were situated in the vertebrae both above and below the previously herniated disc/discs. Ten patients had MC at 1 level, and 1 had MC at 2 levels. The affected levels were 1 at L2/L3, 6 at L4 /L5, and 5 at L5/S1. All had a previous disc herniation and MC larger than 4 mm in diameter. Technically satisfactory PET scans were obtained. However, PET imaging showed no increases in metabolism in any vertebra or disc of any patient. Modic type 1 changes do not reveal themselves by showing increased metabolism with ordinary FDG PET imaging. PET tracers illuminating inflammation are being developed and hopefully may become more successful. (orig.)

  9. PET imaging in patients with Modic changes

    International Nuclear Information System (INIS)

    The aim of this study was via PET imaging to reveal if any highly metabolic processes were occurring in Modic changes type 1 and/or in the adjacent discs. Modic changes (MC) are signal changes in the vertebral endplate and body visualised by magnetic resonance imaging (MRI). MC are strongly associated with low back pain (LBP). MC type 1 appear to be inflammation on MRI, and histological and biochemical findings make it highly likely that an inflammation is present. Though MC is painful no known treatment is available, and it is unknown which entities affect the progress or regress of MC. The changes observed on MRI are slow and take months to develop, but faster changes in the metabolism might provide a platform for monitoring patients. Patients from The Back Centre Funen, with low back pain in the area of L1 to S1, MC type 1 in L1 to L5, and a previous herniated lumbar disc. All patients had a PET scan using FDG (18F-fluorodeoxyglucose) as tracer. Included in the study were 11 patients, 4 women and 7 men, mean age 48.1 year (range 20-65). All MC were situated in the vertebrae both above and below the previously herniated disc/discs. Ten patients had MC at 1 level, and 1 had MC at 2 levels. The affected levels were 1 at L2/L3, 6 at L4 /L5, and 5 at L5/S1. All had a previous disc herniation and MC larger than 4 mm in diameter. Technically satisfactory PET scans were obtained. However, PET imaging showed no increases in metabolism in any vertebra or disc of any patient. Modic type 1 changes do not reveal themselves by showing increased metabolism with ordinary FDG PET imaging. PET tracers illuminating inflammation are being developed and hopefully may become more successful. (orig.)

  10. Pet imaging of estrogen receptors in breast cancer

    International Nuclear Information System (INIS)

    The development of radiopharmaceutical for imaging steroid receptors in breast cancer could have considerable clinical value because of the known relationship between the levels of steroid receptors, particularly for estrogen and progestin, and the natural history and response of this cancer to therapy. We recently reported preliminary clinical investigation of a new radiopharmaceutical, 16α-[18F]fluoro-estradiol-17β (FES), which had shown highly favorable biodistribution as an estrogen receptor ligand in animals. Twelve women undergoing preliminary evaluation for new breast masses and later confirmed to have breast cancer were studied with positron emission tomography (PET) and FES. PET-measured primary tumor uptake of the tracer was shown to have an excellent correlation with tumor estrogen receptor concentration (r = 0.96) determined by in vitro techniques. PET images demonstrated primary breast cancers, as well as several foci of axillary metastases. Additionally, one distant site of metastasis on the anterior chest wall was visualized. To further evaluate this radioligand, additional patients with breast cancer and documented osseous and soft tissue metastases have been studied prior to and after initiation of antiestrogen chemotherapy (tamoxifen). PET imaging before antiestrogen therapy showed multiple metastatic sites. After initiation of therapy, the uptake of the FES was dramatically reduced

  11. Pet Face: Mechanisms Underlying Human-Animal Relationships

    OpenAIRE

    Borgi, Marta; Cirulli, Francesca

    2016-01-01

    Accumulating behavioral and neurophysiological studies support the idea of infantile (cute) faces as highly biologically relevant stimuli rapidly and unconsciously capturing attention and eliciting positive/affectionate behaviors, including willingness to care. It has been hypothesized that the presence of infantile physical and behavioral features in companion (or pet) animals (i.e., dogs and cats) might form the basis of our attraction to these species. Preliminary evidence has indeed shown...

  12. Combined PET/MR imaging in neurology

    DEFF Research Database (Denmark)

    Andersen, Flemming Littrup; Ladefoged, Claes Nøhr; Beyer, Thomas;

    2014-01-01

    AIM: Combined PET/MR systems have now become available for clinical use. Given the lack of integrated standard transmission (TX) sources in these systems, attenuation and scatter correction (AC) must be performed using the available MR-images. Since bone tissue cannot easily be accounted for duri...

  13. PET Imaging - from Physics to Clinical Molecular Imaging

    Science.gov (United States)

    Majewski, Stan

    2008-03-01

    From the beginnings many years ago in a few physics laboratories and first applications as a research brain function imager, PET became lately a leading molecular imaging modality used in diagnosis, staging and therapy monitoring of cancer, as well as has increased use in assessment of brain function (early diagnosis of Alzheimer's, etc) and in cardiac function. To assist with anatomic structure map and with absorption correction CT is often used with PET in a duo system. Growing interest in the last 5-10 years in dedicated organ specific PET imagers (breast, prostate, brain, etc) presents again an opportunity to the particle physics instrumentation community to contribute to the important field of medical imaging. In addition to the bulky standard ring structures, compact, economical and high performance mobile imagers are being proposed and build. The latest development in standard PET imaging is introduction of the well known TOF concept enabling clearer tomographic pictures of the patient organs. Development and availability of novel photodetectors such as Silicon PMT immune to magnetic fields offers an exciting opportunity to use PET in conjunction with MRI and fMRI. As before with avalanche photodiodes, particle physics community plays a leading role in developing these devices. The presentation will mostly focus on present and future opportunities for better PET designs based on new technologies and methods: new scintillators, photodetectors, readout, software.

  14. [11C]PR04.MZ, a promising DAT ligand for low concentration imaging: synthesis, efficient 11C-0-methylation and initial small animal PET studies

    Energy Technology Data Exchange (ETDEWEB)

    Riss, P.J.; Hooker, J.; Alexoff, D.; Kim, Sung-Won; Fowler, J.S.; Roesch, F.

    2009-05-01

    PR04.MZ was designed as a highly selective dopamine transporter inhibitor, derived from natural cocaine. Its binding profile indicates that [{sup 11}C]PR04.MZ may be suited as a PET radioligand for the non-invasive exploration of striatal and extrastriatal DAT populations. As a key feature, its structural design facilitates both, labelling with fluorine-18 at its terminally fluorinated butynyl moiety and carbon-11 at its methyl ester function. The present report concerns the efficient [{sup 11}C]MeI mediated synthesis of [{sup 11}C]PR04.MZ from an O-desmethyl precursor trifluoroacetic acid salt with Rb{sub 2}CO{sub 3} in DMF in up to 95 {+-} 5% labelling yield. A preliminary {mu}PET-experiment demonstrates the reversible, highly specific binding of [{sup 11}C]PR04.MZ in the brain of a male Sprague-Dawley rat.

  15. Performance evaluation of a high-sensitivity large-aperture small-animal PET scanner. ClairvivoPET

    International Nuclear Information System (INIS)

    In this study, we evaluated the performance of a newly commercialized small-animal positron emission tomography (PET) scanner, ClairvivoPET, which provides significant advantages in spatial resolution, sensitivity, and quantitative accuracy. This scanner consists of depth of interaction detector modules with a large axial extent of 151 mm and an external 137Cs source for attenuation correction. Physical performances, resolution, sensitivity, scatter fraction (SF), counting rate including noise equivalent count (NEC) rate, quantitative accuracy versus activity strength, and transmission accuracy, were measured and evaluated. Animal studies were also performed. Transaxial spatial resolution, measured with a capillary tube, was 1.54 mm at the center and 2.93 mm at a radial offset of 40 mm. The absolute sensitivity was 8.2% at the center, and SFs for mouse- and rat-sized phantoms were 10.7% and 24.2%, respectively. Peak NEC rates for mouse- and rat-sized uniform cylindrical phantoms were 328 kcps at 173 kBq/ml and 119 kcps at 49 kBq/ml, respectively. The quantitative stability of emission counts against activity strength was within 2% over 5 half-lives, ranging from 0.6 MBq to 30 MBq. Transmission measurement based on segmented attenuation correction allowed 6-min and 10-min scans for mouse- and rat-sized cylindrical phantoms, respectively. Rat imaging injected with 18F-NaF resulted in visibility of fine bone structures, and mouse imaging injected with 18F-D-fluoromethyl tyrosine demonstrated the feasibility of using this system to obtain simultaneous time activity curves from separate regions, such as for the heart and tumors. ClairvivoPET is well suited to quantitative imaging even with short scan times, and will provide a number of advantages in new drug development and for kinetic measurement in molecular imaging. (author)

  16. PET ANIMALS (CATS AND DOGS) OWNERS PROSPECTS FOR THE VETERINARY CLINICS

    OpenAIRE

    DEMİR, Pınar; UĞURLU KOÇ, Aysun

    2014-01-01

    In this study, the views and expectations of pet animal owners were determined for their veterinary clinic. The material of this study was obtained from a survey conducted with the owners of 102 pet animals in Ankara Altinpark. 55.9% of the pet owners, who surveyed, were  female and the average age of pet owners were 34.9±1.28 and having pet animals average 8.2±0.79 years. The study also determined that almost 55% of animal breeders who surveyed feed the cat. The average monthly income of the...

  17. PET image reconstruction: mean, variance, and optimal minimax criterion

    Science.gov (United States)

    Liu, Huafeng; Gao, Fei; Guo, Min; Xue, Liying; Nie, Jing; Shi, Pengcheng

    2015-04-01

    Given the noise nature of positron emission tomography (PET) measurements, it is critical to know the image quality and reliability as well as expected radioactivity map (mean image) for both qualitative interpretation and quantitative analysis. While existing efforts have often been devoted to providing only the reconstructed mean image, we present a unified framework for joint estimation of the mean and corresponding variance of the radioactivity map based on an efficient optimal min-max criterion. The proposed framework formulates the PET image reconstruction problem to be a transformation from system uncertainties to estimation errors, where the minimax criterion is adopted to minimize the estimation errors with possibly maximized system uncertainties. The estimation errors, in the form of a covariance matrix, express the measurement uncertainties in a complete way. The framework is then optimized by ∞-norm optimization and solved with the corresponding H∞ filter. Unlike conventional statistical reconstruction algorithms, that rely on the statistical modeling methods of the measurement data or noise, the proposed joint estimation stands from the point of view of signal energies and can handle from imperfect statistical assumptions to even no a priori statistical assumptions. The performance and accuracy of reconstructed mean and variance images are validated using Monte Carlo simulations. Experiments on phantom scans with a small animal PET scanner and real patient scans are also conducted for assessment of clinical potential.

  18. Energy dependence of scatter components in multispectral PET imaging

    International Nuclear Information System (INIS)

    High resolution images in PET based on small individual detectors are obtained at the cost of low sensitivity and increased detector scatter. These limitations can be partially overcome by enlarging discrimination windows to include more low-energy events and by developing more efficient energy-dependent methods to correct for scatter radiation from all sources. The feasibility of multispectral scatter correction was assessed by decomposing response functions acquired in multiple energy windows into four basic components: object, collimator and detector scatter, and trues. The shape and intensity of these components are different and energy-dependent. They are shown to contribute to image formation in three ways: useful (true), potentially useful (detector scatter), and undesirable (object and collimator scatter) information to the image over the entire energy range. With the Sherbrooke animal PET system, restoration of detector scatter in every energy window would allow nearly 90% of all detected events to participate in image formation. These observations suggest that multispectral acquisition is a promising solution for increasing sensitivity in high resolution PET. This can be achieved without loss of image quality if energy-dependent methods are made available to preserve useful events as potentially useful events are restored and undesirable events removed

  19. Quantitative Comparison of PET/MR and PET/CT for Imaging of Lymphoma Patients

    OpenAIRE

    Olsen, Silje Kjærnes

    2015-01-01

    Positron emission tomography/computed tomography (PET/CT), a multimodality imaging tool, is today the golden standard in diagnosis, staging and response monitoring of lymphoma patients, while it is investigated if positron emission tomography/magnetic resonance (PET/MR) is superior to PET/CT and should be the gold standard in imaging of lymphoma patients in the future. In this study, PET/MR and PET/CT have been quantitatively compared for imaging of lymphoma patients, by the semi-quanti...

  20. PET Imaging in Huntington’s Disease

    Science.gov (United States)

    Roussakis, Andreas-Antonios; Piccini, Paola

    2015-01-01

    To date, little is known about how neurodegeneration and neuroinflammation propagate in Huntington’s disease (HD). Unfortunately, no treatment is available to cure or reverse the progressive decline of function caused by the disease, thus considering HD a fatal disease. Mutation gene carriers typically remain asymptomatic for many years although alterations in the basal ganglia and cortex occur early on in mutant HD gene–carriers. Positron Emission Tomography (PET) is a functional imaging technique of nuclear medicine which enables in vivo visualization of numerous biological molecules expressed in several human tissues. Brain PET is most powerful to study in vivo neuronal and glial cells function as well as cerebral blood flow in a plethora of neurodegenerative disorders including Parkinson’s disease, Alzheimer’s and HD. In absence of HD–specific biomarkers for monitoring disease progression, previous PET studies in HD were merely focused on the study of dopaminergic terminals, cerebral blood flow and glucose metabolism in manifest and premanifest HD–gene carriers. More recently, research interest has been exploring novel PET targets in HD including the state of phosphodiesterse expression and the role of activated microglia. Hence, a better understanding of the HD pathogenesis mechanisms may lead to the development of targeted therapies. PET imaging follow–up studies with novel selective PET radiotracers such as 11C-IMA–107 and 11C-PBR28 may provide insight on disease progression and identify prognostic biomarkers, elucidate the underlying HD pathology and assess novel pharmaceutical agents and over time. PMID:26683130

  1. PET imaging clinical trials: standards for good image quality

    International Nuclear Information System (INIS)

    Full text: Imaging holds a promising place in the drug development process and clinical trials. In recent times, scientists and researchers have realized that imaging enables them to look for new surrogate endpoints and accelerate the process of drug development. As the number of such trials is increasing every year, there is a growing awareness for the need of quality in imaging trials, so as to avoid imaging issues, reduce losses due to non-evaluable imaging and improve subject safety. This paper is an attempt to address the need of standards for good quality image in clinical trials which use imaging. The main focus of the paper is to describe the various acquisition options in PET-CT available for medical imaging, their applicability in drug development process and clinical trials, emphasize the need to identify possible sources that could possibly impact the quality of images, ways of standardizing the equipments and minimizing the variability of different scanners. Additionally this paper will look into the importance of an expert medical imaging group, imaging protocols, quality assurance programs, and image assessment post acquisition for technical compliance and image quality. A reference of standards as prescribed by various scientific bodies and organizations will also be reviewed. In this paper the focus will be mainly to discuss aspects of PET-CT imaging in clinical trials. PET-CT has the potential to be best for response monitoring to therapy and early detection of disease compared to all other imaging modalities such as CT, MRI, gamma camera, SPECT, ultrasonography etc. In research, PET imaging can help in understanding the pharmacokinetics of a molecule, i.e. kinetic modeling and provides various imaging options, qualitative and quantitative. PET-CT provides anatomical as well as functional information and has the potential to be highly reproducible. The paper emphasizes good imaging practices and its relevance, especially when we are not just

  2. PET imaging in pediatric Hodgkin's lymphoma

    International Nuclear Information System (INIS)

    Advances in diagnostic imaging technology, especially functional imaging modalities like positron emission tomography (PET), have significantly influenced the staging and treatment approaches used for pediatric Hodgkin's lymphoma. Today, the majority of children and adolescents diagnosed with Hodgkin's lymphoma will be cured following treatment with noncross-resistant combination chemotherapy alone or in combination with low-dose, involved-field radiation. This success produced a greater appreciation of long-term complications related to radiation, chemotherapy, and surgical staging that prompted significant changes in staging and treatment protocols for children and adolescents with Hodgkin's lymphoma. Contemporary treatment for pediatric Hodgkin's lymphoma uses a risk-adapted approach that reduces the number of combination chemotherapy cycles and radiation treatment fields and doses for patients with localized favorable disease presentation. Advances in diagnostic imaging technology have played a critical role in the development of these risk-adapted treatment regimens. The introduction of computed tomography (CT) provided an accurate and non-invasive modality to define nodal involvement below the diaphragm that motivated the change from surgical to clinical staging. The introduction of functional imaging modalities, like positron emission tomography (PET) scanning, provided the means to correlate tumor activity with anatomic features generated by CT and modify treatment based on tumor response. For centers with access to this modality, PET imaging plays an important role in staging, evaluating tumor response, planning radiation treatment fields, and monitoring after completion of therapy for pediatric Hodgkin's lymphoma. (orig.)

  3. PET CT imaging: the Philippine experience

    International Nuclear Information System (INIS)

    Currently, the most discussed fusion imaging is PET CT. Fusion technology has tremendous potential in diagnostic imaging to detect numerous conditions such as tumors, Alzheimer's disease, dementia and neural disorders. The fusion of PET with CT helps in the localization of molecular abnormalities, thereby increasing diagnostic accuracy and differentiating benign or artefact lesions from malignant diseases. It uses a radiotracer called fluro deoxyglucose that gives a clear distinction between pathological and physiological uptake. Interest in this technology is increasing and additional clinical validation are likely to induce more health care providers to invest in combined scanners. It is hope that in time, a better appreciation of its advantages over conventional and traditional imaging modalities will be realized. The first PET CT facility in the country was established at the St. Luke's Medical Center in Quezon City in 2008 and has since then provided a state-of-the art imaging modality to its patients here and those from other countries. The paper will present the experiences so far gained from its operation, including the measures and steps currently taken by the facility to ensure optimum workers and patient safety. Plans and programs to further enhance the awareness of the Filipino public on this advanced imaging modality for an improved health care delivery system may also be discussed briefly. (author)

  4. PET imaging in pediatric neuroradiology: current and future applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sunhee [Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States); Salamon, Noriko [UCLA David Geffen School of Medicine at UCLA, Department of Radiology, Ronald Reagan UCLA Medical Center, Los Angeles, CA (United States); Jackson, Hollie A.; Blueml, Stefan [Keck School of Medicine of USC, Department of Radiology, Childrens Hospital Los Angeles, Los Angeles, CA (United States); Panigrahy, Ashok [Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States); Keck School of Medicine of USC, Department of Radiology, Childrens Hospital Los Angeles, Los Angeles, CA (United States)

    2010-01-15

    Molecular imaging with positron emitting tomography (PET) is widely accepted as an essential part of the diagnosis and evaluation of neoplastic and non-neoplastic disease processes. PET has expanded its role from the research domain into clinical application for oncology, cardiology and neuropsychiatry. More recently, PET is being used as a clinical molecular imaging tool in pediatric neuroimaging. PET is considered an accurate and noninvasive method to study brain activity and to understand pediatric neurological disease processes. In this review, specific examples of the clinical use of PET are given with respect to pediatric neuroimaging. The current use of co-registration of PET with MR imaging is exemplified in regard to pediatric epilepsy. The current use of PET/CT in the evaluation of head and neck lymphoma and pediatric brain tumors is also reviewed. Emerging technologies including PET/MRI and neuroreceptor imaging are discussed. (orig.)

  5. Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jin Ho; Choi, Yong, E-mail: ychoi.image@gmail.com; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun [Department of Electronic Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 121-742 (Korea, Republic of); Oh, Chang Hyun; Park, Hyun-wook [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Kyung Min; Kim, Jong Guk [Korea Institute of Radiological and Medical Science, 75 Nowon-ro, Nowon-gu, Seoul 139-709 (Korea, Republic of)

    2015-05-15

    Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

  6. Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

  7. Development of image reconstruction and correction techniques in PET/CT and PET/MR imaging

    OpenAIRE

    Mehranian, Abolfazl

    2015-01-01

    Positron emission tomography (PET) is one of the leading molecular imaging techniques for the non-invasive detection and quantitative assessment of a variety of biochemical processes associated with neoplasms and physiopathological conditions. Following injection of a positron-emitting radiotracer to the patient, the PET scanner measures the biodistribution and kinetics of the administered radiopharmaceutical. However, this modality does not provide the anatomical information necessary for lo...

  8. Childhood pet ownership, attachment to pets, and subsequent meat avoidance. The mediating role of empathy toward animals.

    Science.gov (United States)

    Rothgerber, Hank; Mican, Frances

    2014-08-01

    Researchers studying childhood pet ownership outcomes do not typically focus on measures of adult diet, and those studying the psychology of meat consumption do not normally consider early experiences with companion animals. The present research sought to integrate these two areas by examining relationships between childhood pet ownership, pet attachment, empathy toward animals, belief in human-animal similarity, meat avoidance, and justifications for eating meat. Results from 273 individuals responding to a survey on an internet platform revealed that participants with greater childhood attachment to a pet reported greater meat avoidance as adults, an effect that disappeared when controlling for animal empathy. Greater childhood pet attachment was also related to the use of indirect, apologetic justifications for meat consumption, and this effect too, was mediated by empathy toward animals. Child pet ownership itself predicted views toward animals but not dietary behavior or meat-eating justifications. The authors propose a sequence of events by which greater childhood pet attachment leads to increased meat avoidance, focusing on the central role played by empathy toward animals. PMID:24704704

  9. Accuracy and reproducibility of tumor positioning during prolonged and multi-modality animal imaging studies

    Science.gov (United States)

    Zhang, Mutian; Huang, Minming; Le, Carl; Zanzonico, Pat B.; Claus, Filip; Kolbert, Katherine S.; Martin, Kyle; Ling, C. Clifton; Koutcher, Jason A.; Humm, John L.

    2008-10-01

    Dedicated small-animal imaging devices, e.g. positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI) scanners, are being increasingly used for translational molecular imaging studies. The objective of this work was to determine the positional accuracy and precision with which tumors in situ can be reliably and reproducibly imaged on dedicated small-animal imaging equipment. We designed, fabricated and tested a custom rodent cradle with a stereotactic template to facilitate registration among image sets. To quantify tumor motion during our small-animal imaging protocols, 'gold standard' multi-modality point markers were inserted into tumor masses on the hind limbs of rats. Three types of imaging examination were then performed with the animals continuously anesthetized and immobilized: (i) consecutive microPET and MR images of tumor xenografts in which the animals remained in the same scanner for 2 h duration, (ii) multi-modality imaging studies in which the animals were transported between distant imaging devices and (iii) serial microPET scans in which the animals were repositioned in the same scanner for subsequent images. Our results showed that the animal tumor moved by less than 0.2-0.3 mm over a continuous 2 h microPET or MR imaging session. The process of transporting the animal between instruments introduced additional errors of ~0.2 mm. In serial animal imaging studies, the positioning reproducibility within ~0.8 mm could be obtained.

  10. Accuracy and reproducibility of tumor positioning during prolonged and multi-modality animal imaging studies

    International Nuclear Information System (INIS)

    Dedicated small-animal imaging devices, e.g. positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI) scanners, are being increasingly used for translational molecular imaging studies. The objective of this work was to determine the positional accuracy and precision with which tumors in situ can be reliably and reproducibly imaged on dedicated small-animal imaging equipment. We designed, fabricated and tested a custom rodent cradle with a stereotactic template to facilitate registration among image sets. To quantify tumor motion during our small-animal imaging protocols, 'gold standard' multi-modality point markers were inserted into tumor masses on the hind limbs of rats. Three types of imaging examination were then performed with the animals continuously anesthetized and immobilized: (i) consecutive microPET and MR images of tumor xenografts in which the animals remained in the same scanner for 2 h duration, (ii) multi-modality imaging studies in which the animals were transported between distant imaging devices and (iii) serial microPET scans in which the animals were repositioned in the same scanner for subsequent images. Our results showed that the animal tumor moved by less than 0.2-0.3 mm over a continuous 2 h microPET or MR imaging session. The process of transporting the animal between instruments introduced additional errors of ∼0.2 mm. In serial animal imaging studies, the positioning reproducibility within ∼0.8 mm could be obtained.

  11. An image quality approach for optimizing {sup 124}I PET imaging on Siemens Inveon PET Scanner

    Energy Technology Data Exchange (ETDEWEB)

    Yu, A Ram; Kim, Jin Su; An, Gwang Il; Woo, Sang Keun; Kim, Jong Guk; Park, Ji Ae; Cheon, Gi Jeong; Kim, Byeong Il; Choi, Chang Woon; Lim, Sang Moo; Kim, Kyeong Min [Korea Institute Radiological and Medical Science, Seoul (Korea, Republic of); Kim, Hee Joung [College of Health Science, Yonsei University, Wonju (Korea, Republic of)

    2010-10-15

    {sup 124}I has a long half life of 4.2 days that is suitable for imaging over several days during the biological uptake and washout of radioiodine. However {sup 124}I has a low positron branching ratio (23%). High-energy {gamma}- photons (602 keV to 1,326 keV) are emitted in cascade with the positrons. These cascade {gamma}- photons degrade the image quality. To find optimal parameter, image quality of the Inveon {sup 124}I PET scanner with various energy window settings was measured based on the NEMA NU4-standars and compared with those of {sup 18}F PET

  12. Why Did You Choose This Pet?: Adopters and Pet Selection Preferences in Five Animal Shelters in the United States

    OpenAIRE

    Carla Vela; Heather Mohan-Gibbons; Emily Weiss; Katherine Miller

    2012-01-01

    Simple Summary This study examined reasons why adopters chose their pet in an animal shelter, what behaviors were first exhibited by the pet to the adopter, what information was important during their selection process, and the relative importance of seeing the animals’ behavior in various contexts. Abstract Responses from an adopter survey (n = 1,491) determined reasons for pet selection, type of information received by the adopter, and the context in which the animal’s behavior was observed...

  13. BIODISTRIBUTION AND PET IMAGING OF [18F]-FLUOROADENOSINE DERIVATIVES

    Science.gov (United States)

    Alauddin, Mian M.; Shahinian, Antranik; Park, Ryan; Tohme, Michael; Fissekis, John D.; Conti, Peter S.

    2007-01-01

    Introduction: Many fluorinated analogues of adenosine nucleoside have been synthesized and studied as potential antitumor and antiviral agents. Earlier we reported radiosynthesis of 2′-deoxy-2′-[18F]fluoro-1-β-D-arabinofuranosyl-adenine ([18F]-FAA) and 3′-deoxy-3′-[18F]fluoro-1-β-D-xylofuranosyl-adenine ([18F]FXA). Now we report their in vivo studies including blood clearance, biodistribution and micro-PET imaging in tumor-bearing nude mice. Methods: Tumors were grown in six weeks old athymic nude mice (Harlan, Indianapolis, IN) by inoculation of HT-29 cells, wild type cells in the left flank and transduced cells with HSV-tk on the right flank. When the tumor was about 1 cm in size, animals were injected with these radiotracers for in vivo studies, including blood clearance, micro-PET imaging and biodistribution. Results: Uptake of [18F]FAA in tumor was 3.3-fold higher than blood, with highest uptake in the spleen. Maximum uptake of [18F]FXA was observed in the heart compared to other organs. There was no tumor uptake of [18F]FXA. Biodistribution results were supported by micro-PET images, which also showed very high uptake of [18F]FAA in spleen and visualization of tumors, and high uptake of [18F]FXA in the heart. Conclusion: These results suggest that [18F]FAA may be useful for tumor imaging, while [18F]FXA may have potential as a heart imaging agent with PET. PMID:17383576

  14. Improved attenuation correction for freely moving animal brain PET studies using a virtual scanner geometry

    Science.gov (United States)

    Angelis, Georgios I.; Ryder, William J.; Kyme, Andre Z.; Fulton, Roger R.; Meikle, Steven R.

    2014-03-01

    Attenuation correction in positron emission tomography brain imaging of freely moving animals can be very challenging since the body of the animal is often within the field of view and introduces a non negligible atten- uating factor that can degrade the quantitative accuracy of the reconstructed images. An attractive approach that avoids the need for a transmission scan involves the generation of the convex hull of the animal's head based on the reconstructed emission images. However, this approach ignores the potential attenuation introduced by the animal's body. In this work, we propose a virtual scanner geometry, which moves in synchrony with the animal's head and discriminates between those events that traverse only the animal's head (and therefore can be accurately compensated for attenuation) and those that might have also traversed the animal's body. For each pose a new virtual scanner geometry was defined and therefore a new system matrix was calculated leading to a time-varying system matrix. This new approach was evaluated on phantom data acquired on the microPET Focus 220 scanner using a custom-made rat phantom. Results showed that when the animal's body is within the FOV and not accounted for during attenuation correction it can lead to bias of up to 10%. On the contrary, at- tenuation correction was more accurate when the virtual scanner was employed leading to improved quantitative estimates (bias <2%), without the need to account for the animal's body.

  15. PET imaging of human cardiac opioid receptors

    International Nuclear Information System (INIS)

    The presence of opioid peptides and receptors and their role in the regulation of cardiovascular function has been previously demonstrated in the mammalian heart. The aim of this study was to image μ and δ opioid receptors in the human heart using positron emission tomography (PET). Five subjects (three females, two males, 65±8 years old) underwent PET scanning of the chest with [11C]carfentanil ([11C]CFN) and [11C]-N-methyl-naltrindole ([11C]MeNTI) and the images were analyzed for evidence of opioid receptor binding in the heart. Either [11C]CFN or [11C]MeNTI (20 mCi) was injected i.v. with subsequent dynamic acquisitions over 90 min. For the blocking studies, either 0.2 mg/kg or 1 mg/kg of naloxone was injected i.v. 5 min prior to the injection of [11C]CFN and [11C]MeNTI, respectively. Regions of interest were placed over the left ventricle, left ventricular chamber, lung and skeletal muscle. Graphical analysis demonstrated average baseline myocardial binding potentials (BP) of 4.37±0.91 with [11C]CFN and 3.86±0.60 with [11C]MeNTI. Administration of 0.2 mg/kg naloxone prior to [11C]CFN produced a 25% reduction in BP in one subject in comparison with baseline values, and a 19% decrease in myocardial distribution volume (DV). Administration of 1 mg/kg of naloxone before [11C]MeNTI in another subject produced a 14% decrease in BP and a 21% decrease in the myocardial DV. These results demonstrate the ability to image these receptors in vivo by PET. PET imaging of cardiac opioid receptors may help to better understand their role in cardiovascular pathophysiology and the effect of abuse of opioids and drugs on heart function. (orig.)

  16. SEGMENTATION OF LUNG CANCER PET SCAN IMAGES USING FUZZY CMEANS

    OpenAIRE

    Santhosh T; Narasimha Prasad L V

    2014-01-01

    Image segmentation plays a vital role in medical image processing. Eventually, the proposed work is subjected to classify the tumour and non-tumour parts, followed by the segmentation of tumour region in PET scan images. Lung cancer has been the largest cause of cancer deaths. This paper focuses on Fuzzy C means algorithm for Lung tumour part segmentation of PET scan images to diagnose accurately the region of cancer. A PET scan can often detect cellular level metabolic changes at the earl...

  17. A rat head holder for simultaneous scanning of two rats in small animal PET scanners: Design, construction, feasibility testing and kinetic validation

    OpenAIRE

    Cheng, Tee Ean; Yoder, Karmen K; Normandin, Marc D.; Risacher, Shannon L; Converse, Alexander K; Hampel, Joseph A; Miller, Michael A.; Morris, Evan D

    2008-01-01

    To reduce imaging costs, we designed a head holder for scanning two rats simultaneously in small animal PET scanners. Our goals were (i) to maintain high sensitivity and (ii) to minimize repositioning error between scans.

  18. Molecular characterization of pneumococcal isolates from pets and laboratory animals.

    Directory of Open Access Journals (Sweden)

    Mark van der Linden

    Full Text Available BACKGROUND: Between 1986 and 2008 Streptococcus pneumoniae was isolated from 41 pets/zoo animals (guinea pigs (n = 17, cats (n = 12, horses (n = 4, dogs (n = 3, dolphins (n = 2, rat (n = 2, gorilla (n = 1 treated in medical veterinary laboratories and zoos, and 44 laboratory animals (mastomys (multimammate mice; n = 32, mice (n = 6, rats (n = 4, guinea pigs (n = 2 during routine health monitoring in an animal facility. S. pneumoniae was isolated from nose, lung and respiratory tract, eye, ear and other sites. METHODOLOGY/PRINCIPAL FINDINGS: Carriage of the same isolate of S. pneumoniae over a period of up to 22 weeks was shown for four mastomys. Forty-one animals showed disease symptoms. Pneumococcal isolates were characterized by optochin sensitivity, bile solubility, DNA hybridization, pneumolysin PCR, serotyping and multilocus sequence typing. Eighteen of the 32 mastomys isolates (56% were optochin resistant, all other isolates were optochin susceptible. All mastomys isolates were serotype 14, all guinea pig isolates serotype 19F, all horse isolates serotype 3. Rats had serotypes 14 or 19A, mice 33A or 33F. Dolphins had serotype 23F, the gorilla serotype 14. Cats and dogs had many different serotypes. Four isolates were resistant to macrolides, three isolates also to clindamycin and tetracycline. Mastomys isolates were sequence type (ST 15 (serotype 14, an ST/serotype combination commonly found in human isolates. Cats, dogs, pet rats, gorilla and dolphins showed various human ST/serotype combinations. Lab rats and lab mice showed single locus variants (SLV of human STs, in human ST/serotype combinations. All guinea pig isolates showed the same completely new combination of known alleles. The horse isolates showed an unknown allele combination and three new alleles. CONCLUSIONS/SIGNIFICANCE: The isolates found in mastomys, mice, rats, cats, dogs, gorilla and dolphins are most likely identical to human pneumococcal isolates. Isolates from

  19. 77 FR 28799 - Animal Welfare; Retail Pet Stores and Licensing Exemptions

    Science.gov (United States)

    2012-05-16

    ..., testing, experimentation, exhibition, or for use as a pet; or any dog at the wholesale level for hunting...; ] DEPARTMENT OF AGRICULTURE Animal and Plant Health Inspection Service 9 CFR Parts 1 and 2 RIN 0579-AD57 Animal Welfare; Retail Pet Stores and Licensing Exemptions AGENCY: Animal and Plant Health Inspection...

  20. What about animals dealing with working dogs, pets and other animals during terrorism incidents and disasters

    International Nuclear Information System (INIS)

    It is highly likely that K9 teams (patrol, search and rescue, and cadaver) will be exposed to hazardous materials as a result of an act of CBRN terrorism, and thus require decontamination. Service animals and pets which have been exposed to toxic agents and materials will also need to be decontaminated, along with their owners. Emergency evacuation and sheltering plans need to consider how service animals, pets and livestock will be handled. The United States has recently made significant changes to focus in this regard, to the extent that caring for animals must now be addressed in disaster preparedness planning. In this paper we describe lessons learned from work done by the Massachusetts Urban Search and Rescue Team (USAR), and the response to hurricane Katrina, concerning the handling and decontamination of animals following major incidents. We discuss: how the new Federal and state mandates have changed evacuation and sheltering concepts; cooperation among government entities, veterinarians, animal facilities, humane societies, animal rescue organizations and animal owners; and describe some practical considerations and solutions to sheltering and mass decontamination of animals along with their humans.(author)

  1. [¹⁸F]-fluorodeoxyglucose PET imaging of atherosclerosis

    DEFF Research Database (Denmark)

    Blomberg, Björn Alexander; Høilund-Carlsen, Poul Flemming

    2015-01-01

    [(18)F]-fluorodeoxyglucose PET ((18)FDG PET) imaging has emerged as a promising tool for assessment of atherosclerosis. By targeting atherosclerotic plaque glycolysis, a marker for plaque inflammation and hypoxia, (18)FDG PET can assess plaque vulnerability and potentially predict risk of...

  2. Design and construction of a small animal PET/CT scanner combining scintillation Phoswich modules and hybrid pixels detectors

    International Nuclear Information System (INIS)

    The pathway that has been followed by the imXgam team at CPPM was to combine on a single rotating device the detector modules of the small animal PET scanner ClearPET with a photon counting X-ray detector in order to perform simultaneous acquisition of images from the anatomy (X-ray CT) and from the metabolic function (PET) of the common field-of-view. A preliminary study of the hybrid imaging system ClearPET/XPAD3 carried out using Gate led us to form a new PET detection assembly based on 21 Phoswich modules, to fix the design of the PET/CT device, as well as to study and solve the difficulties arising from simultaneous hybrid imaging. Last but not least, the simulation tool also allowed us for thinking how well such a system could judiciously use the spatial and temporal correlations between anatomic and functional information. From an instrumentation point of view, we succeeded to set up the ClearPET/XPAD3 prototype. Once both imaging systems were operational individually, we demonstrated on one side that the ClearPET prototype was perfectly capable of performing correctly in simultaneous acquisition conditions, providing that the detector modules were appropriately shielded. On the other side, the new generation of the hybrid pixel camera using the XPAD3-S chip proved to be quite promising given the good quality of the first reconstructed images. Finally, the proof of concept of simultaneous PET/CT data acquisition was made using a sealed positron source and an X-ray tube. (author)

  3. Inter-subject MR-PET image registration and integration

    International Nuclear Information System (INIS)

    A MR-PET inter-subject image integration technique is developed to provide more precise anatomical location based on a template MR image, and to examine the anatomical variation in sensory-motor stimulation or to obtain cross-subject signal averaging to enhance the delectability of focal brain activity detected by different subject PET images. In this study, a multimodality intrasubject image registration procedure is firstly applied to align MR and PET images of the same subject. The second procedure is to estimate an elastic image transformation that can nonlinearly deform each 3D brain MR image and map them to the template MR image. The estimation procedure of the elastic image transformation is based on a strategy that searches the best local image match to achieve an optimal global image match, iteratively. The final elastic image transformation estimated for each subject will then be used to deform the MR-PET registered PET image. After the nonlinear PET image deformation, MR-PET intersubject mapping, averaging, and fusing are simultaneously accomplished. The developed technique has been implemented to an UNIX based workstation with Motif window system. The software named Elastic-IRIS has few requirements of user interaction. The registered anatomical location of 10 different subjects has a standard deviation of ∼2mm. in the x, y, and z directions. The processing time for one MR-PET inter-subject registration ranged from 20 to 30 minutes on a SUN SPARC-20

  4. An efficient simulator for pinhole imaging of PET isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Goorden, M C; Van der Have, F; Kreuger, R; Beekman, F J, E-mail: m.c.goorden@tudelft.nl [Section of Radiation Detection and Medical Imaging, Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

    2011-03-21

    Today, small-animal multi-pinhole single photon emission computed tomography (SPECT) can reach sub-half-millimeter image resolution. Recently we have shown that dedicated multi-pinhole collimators can also image PET tracers at sub-mm level. Simulations play a vital role in the design and optimization of such collimators. Here we propose and validate an efficient simulator that models the whole imaging chain from emitted positron to detector signal. This analytical simulator for pinhole positron emission computed tomography (ASPECT) combines analytical models for pinhole and detector response with Monte Carlo (MC)-generated kernels for positron range. Accuracy of ASPECT was validated by means of a MC simulator (MCS) that uses a kernel-based step for detector response with an angle-dependent detector kernel based on experiments. Digital phantom simulations with ASPECT and MCS converge to almost identical images. However, ASPECT converges to an equal image noise level three to four orders of magnitude faster than MCS. We conclude that ASPECT could serve as a practical tool in collimator design and iterative image reconstruction for novel multi-pinhole PET.

  5. Optimizing modelling in iterative image reconstruction for preclinical pinhole PET

    Science.gov (United States)

    Goorden, Marlies C.; van Roosmalen, Jarno; van der Have, Frans; Beekman, Freek J.

    2016-05-01

    The recently developed versatile emission computed tomography (VECTor) technology enables high-energy SPECT and simultaneous SPECT and PET of small animals at sub-mm resolutions. VECTor uses dedicated clustered pinhole collimators mounted in a scanner with three stationary large-area NaI(Tl) gamma detectors. Here, we develop and validate dedicated image reconstruction methods that compensate for image degradation by incorporating accurate models for the transport of high-energy annihilation gamma photons. Ray tracing software was used to calculate photon transport through the collimator structures and into the gamma detector. Input to this code are several geometric parameters estimated from system calibration with a scanning 99mTc point source. Effects on reconstructed images of (i) modelling variable depth-of-interaction (DOI) in the detector, (ii) incorporating photon paths that go through multiple pinholes (‘multiple-pinhole paths’ (MPP)), and (iii) including various amounts of point spread function (PSF) tail were evaluated. Imaging 18F in resolution and uniformity phantoms showed that including large parts of PSFs is essential to obtain good contrast-noise characteristics and that DOI modelling is highly effective in removing deformations of small structures, together leading to 0.75 mm resolution PET images of a hot-rod Derenzo phantom. Moreover, MPP modelling reduced the level of background noise. These improvements were also clearly visible in mouse images. Performance of VECTor can thus be significantly improved by accurately modelling annihilation gamma photon transport.

  6. SPECT and PET imaging in Parkinson's disease

    International Nuclear Information System (INIS)

    Parkinson disease (PD) is the second most common neurodegenerative disorder after Alzheimer's dementia (AD) with a prevalence of 2/1000 in the whole population. This number increases to 2/100 in the aging population and the total number of patients will rise further with increasing life expectancy. Modern imaging techniques such as SPECT (single photon emission tomography) and PET(positron emission tomography) can visualize function and molecular structures in the living human brain and are important clinical and research tools in the evaluation of FP. Because the brain dopamine (DA) system plays a pivotal role in the pathogenesis of PD and related disorders most SPECT and PET studies in PD deal with different aspects of DA-ergic function. However, PD also affects noradrenaline (NA) and serotonin (5HT) producing neurons which contribute to non-motor symptoms. Recent SPECT and PET studies also address this issue. SPECT is a technique which is widely available and is increasingly used in the clinical evaluation of PF patients. With SPECT and specific 123I labelled ligands pre- and postsynaptic structures of the nigrostriatal DA-ergic system can be labelled and visualized. Thus, it is possible to detect and to quantify lesions of the DA-ergic system on the one hand and lesions of the striatal output neurons on the other. This technique also enables studies of pharmacological interactions at the receptor level. With the help of β-CIT, a cocaine derivative, and other similar ligands DA transporters (DATs) can be labelled on DA-ergic nerve terminals. DAT imaging clearly differentiates between normal controls and PD patients even in early stages of the disease. Patients with subcortical vascular encephalopathy presenting with symptoms resembling PD ('lower body Parkinson') can be distinguished with high specificity and sensitivity. PET has the advantage of a better resolution and quantification and a larger number of tracers have mainly been used as a research tool. With

  7. An automatic segmentation method for fast imaging in PET

    International Nuclear Information System (INIS)

    A new segmentation method has been developed for PET fast imaging. The technique automatically segments the transmission images into different anatomical regions, it efficiently reduced the PET transmission scan time. The result shows that this method gives only 3 min-scan time which is perfect for attenuation correction of the PET images instead of the original 15-30 min-scan time. This approach has been successfully tested both on phantom and clinical data

  8. PET image reconstruction with rotationally symmetric polygonal pixel grid based highly compressible system matrix

    International Nuclear Information System (INIS)

    To achieve a maximum compression of system matrix in positron emission tomography (PET) image reconstruction, we proposed a polygonal image pixel division strategy in accordance with rotationally symmetric PET geometry. Geometrical definition and indexing rule for polygonal pixels were established. Image conversion from polygonal pixel structure to conventional rectangular pixel structure was implemented using a conversion matrix. A set of test images were analytically defined in polygonal pixel structure, converted to conventional rectangular pixel based images, and correctly displayed which verified the correctness of the image definition, conversion description and conversion of polygonal pixel structure. A compressed system matrix for PET image recon was generated by tap model and tested by forward-projecting three different distributions of radioactive sources to the sinogram domain and comparing them with theoretical predictions. On a practical small animal PET scanner, a compress ratio of 12.6:1 of the system matrix size was achieved with the polygonal pixel structure, comparing with the conventional rectangular pixel based tap-mode one. OS-EM iterative image reconstruction algorithms with the polygonal and conventional Cartesian pixel grid were developed. A hot rod phantom was detected and reconstructed based on these two grids with reasonable time cost. Image resolution of reconstructed images was both 1.35 mm. We conclude that it is feasible to reconstruct and display images in a polygonal image pixel structure based on a compressed system matrix in PET image reconstruction. (authors)

  9. Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Frohwein, Lynn J., E-mail: frohwein@uni-muenster.de; Schäfers, Klaus P. [European Institute for Molecular Imaging, University of Münster, Münster 48149 (Germany); Hoerr, Verena; Faber, Cornelius [Department of Clinical Radiology, University Hospital of Münster, Münster 48149 (Germany)

    2015-07-15

    Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

  10. Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

    International Nuclear Information System (INIS)

    Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

  11. Pet Face: Mechanisms Underlying Human-Animal Relationships

    Science.gov (United States)

    Borgi, Marta; Cirulli, Francesca

    2016-01-01

    Accumulating behavioral and neurophysiological studies support the idea of infantile (cute) faces as highly biologically relevant stimuli rapidly and unconsciously capturing attention and eliciting positive/affectionate behaviors, including willingness to care. It has been hypothesized that the presence of infantile physical and behavioral features in companion (or pet) animals (i.e., dogs and cats) might form the basis of our attraction to these species. Preliminary evidence has indeed shown that the human attentional bias toward the baby schema may extend to animal facial configurations. In this review, the role of facial cues, specifically of infantile traits and facial signals (i.e., eyes gaze) as emotional and communicative signals is highlighted and discussed as regulating the human-animal bond, similarly to what can be observed in the adult-infant interaction context. Particular emphasis is given to the neuroendocrine regulation of the social bond between humans and animals through oxytocin secretion. Instead of considering companion animals as mere baby substitutes for their owners, in this review we highlight the central role of cats and dogs in human lives. Specifically, we consider the ability of companion animals to bond with humans as fulfilling the need for attention and emotional intimacy, thus serving similar psychological and adaptive functions as human-human friendships. In this context, facial cuteness is viewed not just as a releaser of care/parental behavior, but, more in general, as a trait motivating social engagement. To conclude, the impact of this information for applied disciplines is briefly described, particularly in consideration of the increasing evidence of the beneficial effects of contacts with animals for human health and wellbeing. PMID:27014120

  12. PET FACE: MECHANISMS UNDERLYING HUMAN-ANIMAL RELATIONSHIPS

    Directory of Open Access Journals (Sweden)

    Marta eBorgi

    2016-03-01

    Full Text Available Accumulating behavioral and neurophysiological studies support the idea of infantile (cute faces as highly biologically relevant stimuli rapidly and unconsciously capturing attention and eliciting positive/affectionate behaviors, including willingness to care. It has been hypothesized that the presence of infantile physical and behavioral features in companion (or pet animals (i.e. dogs and cats might form the basis of our attraction to these species. Preliminary evidence has indeed shown that the human attentional bias toward the baby schema may extend to animal facial configurations. In this review, the role of facial cues, specifically of infantile traits and facial signals (i.e. eyes gaze as emotional and communicative signals is highlighted and discussed as regulating human-animal bond, similarly to what can be observed in the adult-infant interaction context. Particular emphasis is given to the neuroendocrine regulation of social bond between humans and animals through oxytocin secretion. Instead of considering companion animals as mere baby substitutes for their owners, in this review we highlight the central role of cats and dogs in human lives. Specifically, we consider the ability of companion animals to bond with humans as fulfilling the need for attention and emotional intimacy, thus serving similar psychological and adaptive functions as human-human friendships. In this context, facial cuteness is viewed not just as a releaser of care/parental behavior, but more in general as a trait motivating social engagement. To conclude, the impact of this information for applied disciplines is briefly described, particularly in consideration of the increasing evidence of the beneficial effects of contacts with animals for human health and wellbeing.

  13. Pet Face: Mechanisms Underlying Human-Animal Relationships.

    Science.gov (United States)

    Borgi, Marta; Cirulli, Francesca

    2016-01-01

    Accumulating behavioral and neurophysiological studies support the idea of infantile (cute) faces as highly biologically relevant stimuli rapidly and unconsciously capturing attention and eliciting positive/affectionate behaviors, including willingness to care. It has been hypothesized that the presence of infantile physical and behavioral features in companion (or pet) animals (i.e., dogs and cats) might form the basis of our attraction to these species. Preliminary evidence has indeed shown that the human attentional bias toward the baby schema may extend to animal facial configurations. In this review, the role of facial cues, specifically of infantile traits and facial signals (i.e., eyes gaze) as emotional and communicative signals is highlighted and discussed as regulating the human-animal bond, similarly to what can be observed in the adult-infant interaction context. Particular emphasis is given to the neuroendocrine regulation of the social bond between humans and animals through oxytocin secretion. Instead of considering companion animals as mere baby substitutes for their owners, in this review we highlight the central role of cats and dogs in human lives. Specifically, we consider the ability of companion animals to bond with humans as fulfilling the need for attention and emotional intimacy, thus serving similar psychological and adaptive functions as human-human friendships. In this context, facial cuteness is viewed not just as a releaser of care/parental behavior, but, more in general, as a trait motivating social engagement. To conclude, the impact of this information for applied disciplines is briefly described, particularly in consideration of the increasing evidence of the beneficial effects of contacts with animals for human health and wellbeing. PMID:27014120

  14. PET/CT imaging: what radiologists need to know

    OpenAIRE

    Benamor, M.; Ollivier, L; Brisse, H; Moulin-Romsee, G.; Servois, V.; Neuenschwander, S.

    2007-01-01

    Abstract Positron emission tomography (PET)/computed tomography (CT) imaging is frequently requested in Oncology. Radiologists and nuclear medicine physicians are often asked to perform a panel of imaging examinations as part of the initial staging or follow-up of cancer patients. Medical imaging must therefore integrate polyvalent skills enabling imaging specialists to understand and interpret all types of images. In this context, PET imaging combined with non-enhanced CT, and diagnostic qua...

  15. Accuracy and Radiation Dose of CT-Based Attenuation Correction for Small Animal PET: A Monte Carlo Simulation Study

    International Nuclear Information System (INIS)

    -Small animal PET allows qualitative assessment and quantitative measurement of biochemical processes in vivo, but the accuracy and reproducibility of imaging results can be affected by several parameters. The first aim of this study was to investigate the performance of different CT-based attenuation correction strategies and assess the resulting impact on PET images. The absorbed dose in different tissues caused by scanning procedures was also discussed to minimize biologic damage generated by radiation exposure due to PET/CT scanning. A small animal PET/CT system was modeled based on Monte Carlo simulation to generate imaging results and dose distribution. Three energy mapping methods, including the bilinear scaling method, the dual-energy method and the hybrid method which combines the kVp conversion and the dual-energy method, were investigated comparatively through assessing the accuracy of estimating linear attenuation coefficient at 511 keV and the bias introduced into PET quantification results due to CT-based attenuation correction. Our results showed that the hybrid method outperformed the bilinear scaling method, while the dual-energy method achieved the highest accuracy among the three energy mapping methods. Overall, the accuracy of PET quantification results have similar trend as that for the estimation of linear attenuation coefficients, whereas the differences between the three methods are more obvious in the estimation of linear attenuation coefficients than in the PET quantification results. With regards to radiation exposure from CT, the absorbed dose ranged between 7.29-45.58 mGy for 50-kVp scan and between 6.61-39.28 mGy for 80-kVp scan. For 18F radioactivity concentration of 1.86x105 Bq/ml, the PET absorbed dose was around 24 cGy for tumor with a target-to-background ratio of 8. The radiation levels for CT scans are not lethal to the animal, but concurrent use of PET in longitudinal study can increase the risk of biological effects. The

  16. PET imaging in patients with Modic changes

    DEFF Research Database (Denmark)

    Albert, Hanne; Pedersen, Henrik; Manniche, Claus;

    2009-01-01

    changes observed on MRI are slow and take months to develop, but faster changes in the metabolism might provide a platform for monitoring patients. PATIENTS, METHODS: Patients from The Back Centre Funen, with low back pain in the area of L1 to S1, MC type 1 in L1 to L5, and a previous herniated lumbar...... disc. All patients had a PET scan using FDG (18F-fluorodeoxyglucose) as tracer. RESULTS: Included in the study were 11 patients, 4 women and 7 men, mean age 48.1 year (range 20-65). All MC were situated in the vertebrae both above and below the previously herniated disc/discs. Ten patients had MC at 1...... level, and 1 had MC at 2 levels. The affected levels were 1 at L2/L3, 6 at L4 /L5, and 5 at L5/S1. All had a previous disc herniation and MC larger than 4 mm in diameter. Technically satisfactory PET scans were obtained. However, PET imaging showed no increases in metabolism in any vertebra or disc of...

  17. Performance of three-photon PET imaging: Monte Carlo simulations

    Science.gov (United States)

    Kacperski, Krzysztof; Spyrou, Nicholas M.

    2005-12-01

    We have recently introduced the idea of making use of three-photon positron annihilations in positron emission tomography. In this paper, the basic characteristics of the three-gamma imaging in PET are studied by means of Monte Carlo simulations and analytical computations. Two typical configurations of human and small animal scanners are considered. Three-photon imaging requires high-energy resolution detectors. Parameters currently attainable by CdZnTe semiconductor detectors, the technology of choice for the future development of radiation imaging, are assumed. Spatial resolution is calculated as a function of detector energy resolution and size, position in the field of view, scanner size and the energies of the three-gamma annihilation photons. Possible ways to improve the spatial resolution obtained for nominal parameters, 1.5 cm and 3.2 mm FWHM for human and small animal scanners, respectively, are indicated. Counting rates of true and random three-photon events for typical human and small animal scanning configurations are assessed. A simple formula for minimum size of lesions detectable in the three-gamma based images is derived. Depending on the contrast and total number of registered counts, lesions of a few mm size for human and sub mm for small animal scanners can be detected.

  18. Dual-Modality PET/Ultrasound imaging of the Prostate

    International Nuclear Information System (INIS)

    Functional imaging with positron emission tomography (PET)will detect malignant tumors in the prostate and/or prostate bed, as well as possibly help determine tumor ''aggressiveness''. However, the relative uptake in a prostate tumor can be so great that few other anatomical landmarks are visible in a PET image. Ultrasound imaging with a transrectal probe provides anatomical detail in the prostate region that can be co-registered with the sensitive functional information from the PET imaging. Imaging the prostate with both PET and transrectal ultrasound (TRUS) will help determine the location of any cancer within the prostate region. This dual-modality imaging should help provide better detection and treatment of prostate cancer. LBNL has built a high performance positron emission tomograph optimized to image the prostate.Compared to a standard whole-body PET camera, our prostate-optimized PET camera has the same sensitivity and resolution, less backgrounds and lower cost. We plan to develop the hardware and software tools needed for a validated dual PET/TRUS prostate imaging system. We also plan to develop dual prostate imaging with PET and external transabdominal ultrasound, in case the TRUS system is too uncomfortable for some patients. We present the design and intended clinical uses for these dual imaging systems

  19. Dual-Modality PET/Ultrasound imaging of the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Jennifer S.; Moses, William W.; Pouliot, Jean; Hsu, I.C.

    2005-11-11

    Functional imaging with positron emission tomography (PET)will detect malignant tumors in the prostate and/or prostate bed, as well as possibly help determine tumor ''aggressiveness''. However, the relative uptake in a prostate tumor can be so great that few other anatomical landmarks are visible in a PET image. Ultrasound imaging with a transrectal probe provides anatomical detail in the prostate region that can be co-registered with the sensitive functional information from the PET imaging. Imaging the prostate with both PET and transrectal ultrasound (TRUS) will help determine the location of any cancer within the prostate region. This dual-modality imaging should help provide better detection and treatment of prostate cancer. LBNL has built a high performance positron emission tomograph optimized to image the prostate.Compared to a standard whole-body PET camera, our prostate-optimized PET camera has the same sensitivity and resolution, less backgrounds and lower cost. We plan to develop the hardware and software tools needed for a validated dual PET/TRUS prostate imaging system. We also plan to develop dual prostate imaging with PET and external transabdominal ultrasound, in case the TRUS system is too uncomfortable for some patients. We present the design and intended clinical uses for these dual imaging systems.

  20. PET imaging of human cardiac opioid receptors

    Energy Technology Data Exchange (ETDEWEB)

    Villemagne, Patricia S.R.; Dannals, Robert F. [Department of Radiology, The Johns Hopkins University School of Medicine, 605 N Caroline St., Baltimore, Maryland (United States); Department of Environmental Health Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Ravert, Hayden T. [Department of Radiology, The Johns Hopkins University School of Medicine, 605 N Caroline St., Baltimore, Maryland (United States); Frost, James J. [Department of Radiology, The Johns Hopkins University School of Medicine, 605 N Caroline St., Baltimore, Maryland (United States); Department of Environmental Health Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States)

    2002-10-01

    The presence of opioid peptides and receptors and their role in the regulation of cardiovascular function has been previously demonstrated in the mammalian heart. The aim of this study was to image {mu} and {delta} opioid receptors in the human heart using positron emission tomography (PET). Five subjects (three females, two males, 65{+-}8 years old) underwent PET scanning of the chest with [{sup 11}C]carfentanil ([{sup 11}C]CFN) and [{sup 11}C]-N-methyl-naltrindole ([{sup 11}C]MeNTI) and the images were analyzed for evidence of opioid receptor binding in the heart. Either [{sup 11}C]CFN or [{sup 11}C]MeNTI (20 mCi) was injected i.v. with subsequent dynamic acquisitions over 90 min. For the blocking studies, either 0.2 mg/kg or 1 mg/kg of naloxone was injected i.v. 5 min prior to the injection of [{sup 11}C]CFN and [{sup 11}C]MeNTI, respectively. Regions of interest were placed over the left ventricle, left ventricular chamber, lung and skeletal muscle. Graphical analysis demonstrated average baseline myocardial binding potentials (BP) of 4.37{+-}0.91 with [{sup 11}C]CFN and 3.86{+-}0.60 with [{sup 11}C]MeNTI. Administration of 0.2 mg/kg naloxone prior to [{sup 11}C]CFN produced a 25% reduction in BP in one subject in comparison with baseline values, and a 19% decrease in myocardial distribution volume (DV). Administration of 1 mg/kg of naloxone before [{sup 11}C]MeNTI in another subject produced a 14% decrease in BP and a 21% decrease in the myocardial DV. These results demonstrate the ability to image these receptors in vivo by PET. PET imaging of cardiac opioid receptors may help to better understand their role in cardiovascular pathophysiology and the effect of abuse of opioids and drugs on heart function. (orig.)

  1. Head and neck imaging with PET and PET/CT: artefacts from dental metallic implants

    International Nuclear Information System (INIS)

    Germanium-68 based attenuation correction (PETGe68) is performed in positron emission tomography (PET) imaging for quantitative measurements. With the recent introduction of combined in-line PET/CT scanners, CT data can be used for attenuation correction. Since dental implants can cause artefacts in CT images, CT-based attenuation correction (PETCT) may induce artefacts in PET images. The purpose of this study was to evaluate the influence of dental metallic artwork on the quality of PET images by comparing non-corrected images and images attenuation corrected by PETGe68 and PETCT. Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PETCT in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PETGe68 images were acquired in the same imaging session. Visual analysis of fluorine-18 fluorodeoxyglucose (FDG) distribution in several regions of the head and neck was scored on a 4-point scale in comparison with normal grey matter of the brain in the corresponding PET images. In addition, artefacts adjacent to dental metallic artwork were evaluated. A significant difference in image quality scoring was found only for the lips and the tip of the nose, which appeared darker on non-corrected than on corrected PET images. In 33 patients, artefacts were seen on CT, and in 28 of these patients, artefacts were also seen on PET imaging. In eight patients without implants, artefacts were seen neither on CT nor on PET images. Direct comparison of PETGe68 and PETCT images showed a different appearance of artefacts in 3 of 17 patients. Malignant lesions were equally well visible using both transmission correction methods. Dental implants, non-removable bridgework etc. can cause artefacts in attenuation-corrected images using either a conventional 68Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the non-attenuation-corrected PET images also be evaluated

  2. Cortical surface-based statistical analysis of brain PET images

    International Nuclear Information System (INIS)

    Precise and focal analysis of brain PET using voxel-based statistical mapping is limited due to the innate low spatial resolution of PET images which causes partial volume effect as well as due to the low precision of the image registration. In this study, we propose a cortical surface-based method for the precise analysis of brain PET images in combination with MRI. 18F-FDG brain PET images were acquired using GE ADVANCE PET scanner in 3D mode. 3D T1-weighted axial MR images were acquired from Philips Intera 1.5T scanner with slice thickness 1.5 mm and FOV=22 cm. The first step of analysis, we segmented gray and white matter from the structural T1 images using Freesurfer (MGH, Harvard Medical School) which extract the white matter surface using a deformable surface model. The cortical surface was further parcellated automatically into 85 anatomically relevant brain sub-regions. The second step, we developed a method for registering PET images to MRI in combination with a mutual information algorithm to maximize total metabolic activity within the gray matter band. Partial volume correction of PET image was conducted utilizing the extracted gray matter. The third step, we calculated mean cortical activity along the path from the white matter surface to the gray matter surface. The cortical activity was represented on the spatially normalized surface which statistical evaluation of cortical activity was conducted with. We evaluated the surface-based representation of PET images and the registration of PET images and the registration of PET and MRI utilizing cortical parcellation. The preliminary results showed that our method is very promising in the analysis of subtle cortical activity difference. We proposed a novel surface-based approach of brain PET analysis using high resolution MRI. Cortical Surface-based method was very efficient in the precise representation of brain activity, correction of partial volume effect as well as better spatial normalization

  3. Cortical surface-based statistical analysis of brain PET images

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae Jeong; Kim, Jae Jin; Yoon, Mi Jin; Yoo, Young Hoon; Lee, Jong Doo [School of Medicine, Yonsei University, Seoul (Korea, Republic of)

    2004-07-01

    Precise and focal analysis of brain PET using voxel-based statistical mapping is limited due to the innate low spatial resolution of PET images which causes partial volume effect as well as due to the low precision of the image registration. In this study, we propose a cortical surface-based method for the precise analysis of brain PET images in combination with MRI. {sup 18}F-FDG brain PET images were acquired using GE ADVANCE PET scanner in 3D mode. 3D T1-weighted axial MR images were acquired from Philips Intera 1.5T scanner with slice thickness 1.5 mm and FOV=22 cm. The first step of analysis, we segmented gray and white matter from the structural T1 images using Freesurfer (MGH, Harvard Medical School) which extract the white matter surface using a deformable surface model. The cortical surface was further parcellated automatically into 85 anatomically relevant brain sub-regions. The second step, we developed a method for registering PET images to MRI in combination with a mutual information algorithm to maximize total metabolic activity within the gray matter band. Partial volume correction of PET image was conducted utilizing the extracted gray matter. The third step, we calculated mean cortical activity along the path from the white matter surface to the gray matter surface. The cortical activity was represented on the spatially normalized surface which statistical evaluation of cortical activity was conducted with. We evaluated the surface-based representation of PET images and the registration of PET images and the registration of PET and MRI utilizing cortical parcellation. The preliminary results showed that our method is very promising in the analysis of subtle cortical activity difference. We proposed a novel surface-based approach of brain PET analysis using high resolution MRI. Cortical Surface-based method was very efficient in the precise representation of brain activity, correction of partial volume effect as well as better spatial normalization.

  4. 18F-fluoride PET imaging in a nude rat model of bone metastasis from breast cancer: Comparison with 18F-FDG and bioluminescence imaging

    International Nuclear Information System (INIS)

    Introduction: Clinically-relevant animal models and appropriate imaging diagnostic tools are essential to study cancer and develop novel therapeutics. We evaluated a model of bone metastasis in nude rats by micro-PET and bioluminescence imaging. Methods: A bone metastasis model was produced by intracardiac injection of osteotropic MDA-MB-231Bo-Luc human breast cancer cells into nude rats. Bioluminescence imaging and micro-PET scans using 18F-FDG and 18F-fluoride were acquired serially for 5 weeks. We correlated bioluminescence imaging, 18F-FDG and 18F-fluoride PET images, and histological slides. Results: Multiple bone metastases were successfully evaluated by bioluminescence imaging and 18F-FDG and 18F-fluoride PET scans. Bioluminescence photon flux increased exponentially on weekly follow-up. 18F-FDG PET revealed increased FDG uptake at the spine and bilaterally in the hind legs in week 2 images, and showed a progressive pattern up to 4 weeks that correlated with bioluminescence imaging. 18F-fluoride PET showed minimal abnormal findings in week 2 images, but it showed an irregular pattern at the spine from week 3 or 4 images. On quantitative analysis with standardized uptake values, a pattern of gradual increase was observed from week 2 to week 4 in both 18F-FDG PET and fluoride PET. Histopathological examination confirmed the formation of osteolytic metastasis and necrosis of the distal femur, which appeared as a photon defect on PET scans. Conclusion: Developing bone metastasis from breast cancer in a nude rat model was successfully evaluated with an animal PET imaging system and bioluminescence imaging. This nude rat model of bone metastasis, which can be evaluated by PET imaging, may be a valuable tool for evaluating early responses to novel therapeutics

  5. PET: An Eye-tracking Dataset for Animal-centric PASCAL Object Classes

    OpenAIRE

    Gilani, Syed Omer; Subramanian, Ramanathan; Yan, Yan; Melcher, David; Sebe, Nicu; Winkler, Stefan

    2016-01-01

    We present the Pascal animal classes Eye Tracking database. Our database comprises eye movement recordings compiled from forty users for the bird, cat, cow, dog, horse and sheep {trainval} sets from the VOC 2012 image set. Different from recent eye-tracking databases such as \\cite{kiwon_cvpr13_gaze,PapadopoulosCKF14}, a salient aspect of PET is that it contains eye movements recorded for both the free-viewing and visual search task conditions. While some differences in terms of overall gaze b...

  6. Imaging corn plants with PhytoPET, a modular PET system for plant biology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.; Kross, B.; McKisson, J.; McKisson, J. E.; Weisenberger, A. G.; Xi, W.; Zorn, C.; Bonito, G.; Howell, C. R.; Reid, C. D.; Crowell, A.; Cumberbatch, L. C.; Topp, C.; Smith, M. F.

    2013-11-01

    PhytoPET is a modular positron emission tomography (PET) system designed specifically for plant imaging. The PhytoPET design allows flexible arrangements of PET detectors based on individual standalone detector modules built from single Hamamatsu H8500 position sensitive photomultiplier tubes and pixelated LYSO arrays. We have used the PhytoPET system to perform preliminary corn plant imaging studies at the Duke University Biology Department Phytotron. Initial evaluation of the PhytoPET system to image the biodistribution of the positron emitting tracer {sup 11}C in corn plants is presented. {sup 11}CO{sub 2} is loaded into corn seedlings by a leaf-labeling cuvette and translocation of {sup 11}C-sugars is imaged by a flexible arrangement of PhytoPET modules on each side. The PhytoPET system successfully images {sup 11}C within corn plants and allows for the dynamic measurement of {sup 11}C-sugar translocation from the leaf to the roots.

  7. PET/MR Imaging in Cancers of the Gastrointestinal Tract.

    Science.gov (United States)

    Paspulati, Raj Mohan; Gupta, Amit

    2016-10-01

    PET/computed tomography (PET/CT) is an established hybrid imaging technique for staging and follow-up of gastrointestinal (GI) tract malignancies, especially for colorectal carcinoma. Dedicated hybrid PET/MR imaging scanners are currently available for clinical use. Although they will not replace regular use of PET/CT, they may have utility in selected cases of GI tract malignancies. The superior soft tissue contrast resolution and depiction of anatomy and the functional information obtained from diffusion-weighted imaging (DWI) provided by MR imaging in PET/MR imaging are advantages over CT of PET/CT for T staging and follow-up of rectal carcinoma and for better characterization of liver lesions. Functional information from DWI and use of liver-specific MR imaging contrast agents are an added advantage in follow-up of liver metastases after systemic and locoregional treatment. New radiotracers will improve the utility of PET/MR imaging in staging and follow-up of tumors, which may not be [18F]-2-fluoro-2-deoxy-d-glucose avid, such as hepatocellular carcinoma and neuroendocrine tumors. PET/MR imaging also has application in selected cases of cholangiocarcinoma, gallbladder cancer, and pancreatic carcinoma for initial staging and follow-up assessment. PMID:27593246

  8. Companion animal welfare and possible implications on the human-pet relationship

    Directory of Open Access Journals (Sweden)

    Marina Verga

    2010-01-01

    Full Text Available The role of pets (dogs and cats in particular in human society has changed in recent years. Nowadays pets are an integral part of the human family and this aspect has many social and emotional implications. For their positive effects on human health, pets are also employed in some special and therapeutic activities known by the generic term of “Pet Therapy”. In these programmes the animal becomes an integral part of the therapeutic plan in order to induce some physical, social, emotional, and cognitive improvements in human patients. However, the close bond between companion animals and man is not always the herald of beneficial effects. Sometimes the welfare of pets may be compromised by distress due to many factors, mostly related to the environment and to management by humans. Both behavioural and physiological variables may be analysed in order to evaluate welfare level in pets. Reduced welfare may be indicated by the onset of some behavioural problems, which have usually a multifactorial aetiology, related both to the genetic individual basis and environmental factors. Physiological variables which may be analysed in order to evaluate pet welfare include hormone levels, mainly related to the HPA (hypothalamus-pituitary-adrenal- axis and to the immune systems activations. Behavioural problems may also lead to the relinquishment of pets to shelters. Animals housed in rescue shelters cannot display their ethogram and show behavioural and physiological signs of distress. Thus it is very important to improve the human-pet relationship both by educating owners and reducing the number of stray animals, in accordance with the indications of the European Convention for the Protection of Pet Animals stated at Strasbourg in 1987, mainly as regards pet breeding and welfare. Humans have to realise that adopting pets implies the responsibility to care for their health and welfare, avoiding undue stress in the living environment and improving the

  9. Non-FDG PET imaging of brain tumors

    Institute of Scientific and Technical Information of China (English)

    HUANG Zemin; GUAN Yihui; ZUO Chuantao; ZHANG Zhengwei; XUE Fangping; LIN Xiangtong

    2007-01-01

    Due to relatively high uptake of glucose in the brain cortex, the use of FDG PET imaging is greatly limited in brain tumor imaging, especially for low-grade gliomas and some metastatic tumours. More and more tracers with higher specificity were developed lately for brain tumor imaging. There are 3 main types of non-FDG PET tracers:amino acid tracers, choline tracers and nucleic acid tracers. These tracers are now widely applied in many aspects of brain tumor imaging. This article summarized the general use of non-FDG PET in different aspects of brain tumor imaging.

  10. Performance evaluation of the small-animal PET scanner ClairvivoPET using NEMA NU 4-2008 Standards

    Science.gov (United States)

    Sato, K.; Shidahara, M.; Watabe, H.; Watanuki, S.; Ishikawa, Y.; Arakawa, Y.; Nai, YH; Furumoto, S.; Tashiro, M.; Shoji, T.; Yanai, K.; Gonda, K.

    2016-01-01

    The aim of this study was to evaluate the performance of ClairvivoPET using NEMA NU4 standards. The ClairvivoPET incorporates a LYSO dual depth-of-interaction detector system with 151 mm axial field of view (FOV). Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated using NEMA NU4-2008 standards. Normal mouse imaging was also performed for 10min after intravenous injection of 18F(-)-NaF. Data were compared with 19 other preclinical PET scanners. Spatial resolution measured using full width at half maximum on FBP-ramp reconstructed images was 2.16 mm at radial offset 5 mm of the axial centre FOV. The maximum absolute sensitivity for a point source at the FOV centre was 8.72%. Peak noise equivalent counting rate (NECR) was 415kcps at 14.6MBq ml-1. The uniformity with the image-quality phantom was 4.62%. Spillover ratios in the images of air and water filled chambers were 0.19 and 0.06, respectively. Our results were comparable with the 19 other preclinical PET scanners based on NEMA NU4 standards, with excellent sensitivity because of the large FOV. The ClairvivoPET with iterative reconstruction algorithm also provided sufficient visualization of the mouse spine. The high sensitivity and resolution of the ClairvivoPET scanner provided high quality images for preclinical studies.

  11. MR-based Motion Correction for PET Imaging

    OpenAIRE

    Ouyang, Jinsong; Li, Quanzheng; Fakhri, Georges El

    2013-01-01

    PET image quality is limited by patient motion. Emission data are blurred due to cardiac and/or respiratory motion. Although spatial resolution is 4 mm for standard clinical whole-body PET scanners, the effective resolution can be a low as 1 cm due to motion. Additionally, the deformation of attenuation medium causes image artifacts. Previously, gating is used to “freeze” the motion, but leads to significantly increased noise level. Simultaneous PET-MR modality offers a new way to perform PET...

  12. Full modelling of the MOSAIC animal PET system based on the GATE Monte Carlo simulation code

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) systems dedicated to animal imaging are now widely used for biological studies. The scanner performance strongly depends on the design and the characteristics of the system. Many parameters must be optimized like the dimensions and type of crystals, geometry and field-of-view (FOV), sampling, electronics, lightguide, shielding, etc. Monte Carlo modelling is a powerful tool to study the effect of each of these parameters on the basis of realistic simulated data. Performance assessment in terms of spatial resolution, count rates, scatter fraction and sensitivity is an important prerequisite before the model can be used instead of real data for a reliable description of the system response function or for optimization of reconstruction algorithms. The aim of this study is to model the performance of the Philips Mosaic(TM) animal PET system using a comprehensive PET simulation code in order to understand and describe the origin of important factors that influence image quality. We use GATE, a Monte Carlo simulation toolkit for a realistic description of the ring PET model, the detectors, shielding, cap, electronic processing and dead times. We incorporate new features to adjust signal processing to the Anger logic underlying the Mosaic(TM) system. Special attention was paid to dead time and energy spectra descriptions. Sorting of simulated events in a list mode format similar to the system outputs was developed to compare experimental and simulated sensitivity and scatter fractions for different energy thresholds using various models of phantoms describing rat and mouse geometries. Count rates were compared for both cylindrical homogeneous phantoms. Simulated spatial resolution was fitted to experimental data for 18F point sources at different locations within the FOV with an analytical blurring function for electronic processing effects. Simulated and measured sensitivities differed by less than 3%, while scatter fractions agreed

  13. NEMA NU-04-based performance characteristics of the LabPET-8(TM) small animal PET scanner

    International Nuclear Information System (INIS)

    The objective of this study is to characterize the performance of the preclinical avalanche photodiode (APD)-based LabPET-8(TM) subsystem of the fully integrated trimodality PET/SPECT/CT Triumph(TM) scanner using the National Electrical Manufacturers Association (NEMA) NU 04-2008 protocol. The characterized performance parameters include the spatial resolution, sensitivity, scatter fraction, counts rate performance and image-quality characteristics. The PET system is fully digital using APD-based detector modules with highly integrated electronics. The detector assembly consists of phoswich pairs of Lu1.9Y0.1SiO5 (LYSO) and Lu0.4Gd1.6SiO5 (LGSO) crystals with dimensions of 2 x 2 x 14 mm3 having 7.5 cm axial and 10 cm transverse field of view (FOV). The spatial resolution and sensitivity were measured using a small 22Na point source at different positions in the scanner's FOV. The scatter fraction and count rate characteristics were measured using mouse- and rat-sized phantoms fitted with an18F line source. The overall imaging capabilities of the scanner were assessed using the NEMA image-quality phantom and laboratory animal studies. The NEMA-based radial and tangential spatial resolution ranged from 1.7 mm at the center of the FOV to 2.59 mm at a radial offset of 2.5 cm and from 1.85 mm at the center of the FOV to 1.76 mm at a radial offset of 2.5 cm, respectively. Iterative reconstruction improved the spatial resolution to 0.84 mm at the center of the FOV. The total absolute system sensitivity is 12.74% for an energy window of 250-650 keV. For the mouse-sized phantom, the peak noise equivalent count rate (NECR) is 183 kcps at 2.07 MBq cc-1, whereas the peak true count rate is 320 kcps at 2.5 MBq cc-1 with a scatter fraction of 19%. The rat-sized phantom had a scatter fraction of 31%, with a peak NECR of 67 kcps at 0.23 MBq cc-1 and a peak true count rate of 186 kcps at 0.27 MBq cc-1. The average activity concentration and percentage standard deviation were 126

  14. Imaging of I{sub 2}-imidazoline receptors by small-animal PET using 2-(3-fluoro-[4-{sup 11}C]tolyl)-4,5-dihydro-1H-imidazole ([{sup 11}C]FTIMD)

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Kazunori, E-mail: kawamur@nirs.go.j [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Naganawa, Mika [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Konno, Fujiko; Yui, Joji [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Wakizaka, Hidekatsu [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Yamasaki, Tomoteru; Yanamoto, Kazuhiko; Hatori, Akiko [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Takei, Makoto [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Tokyo Nuclear Services Co., Ltd., Tokyo 110-0016 (Japan); Yoshida, Yuichiro [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); SHI Accelerator Service Ltd., Tokyo 141-0032 (Japan); Sakaguchi, Kazuya [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Fukumura, Toshimitsu [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Kimura, Yuichi [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Zhang, Ming-Rong [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2010-07-15

    Introduction: Imidazoline receptors (IRs) have been established as distinct receptors, and have been categorized into at least two subtypes (I{sub 1}R and I{sub 2}R). I{sub 2}Rs are associated with depression, Alzheimer's disease, Huntington's disease and Parkinson's disease. A few positron emission tomography (PET) probes for I{sub 2}Rs have been synthesized, but a selective PET probe has not been evaluated for the imaging of I{sub 2}Rs by PET. We labeled a selective I{sub 2}R ligand 2-(3-fluoro-4-tolyl)-4,5-dihydro-1H-imidazole (FTIMD) with {sup 11}C and performed the first imaging of I{sub 2}Rs by PET using 2-(3-fluoro-[4-{sup 11}C]tolyl)-4,5-dihydro-1H-imidazole ([{sup 11}C]FTIMD). Methods: [{sup 11}C]FTIMD was prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [{sup 11}C]methyl iodide in the presence of tris(dibenzylideneacetone)dipalladium(0) and tri(o-tol)phosphine. Biodistribution was investigated in rats by tissue dissection. [{sup 11}C]FTIMD metabolites were measured in brain tissues and plasma. Dynamic PET scans were acquired in rats, and the kinetic parameters estimated. Results: [{sup 11}C]FTIMD was successfully synthesized with a suitable radioactivity for the injection. Co-injection with 0.1 mg/kg of cold FTIMD and BU224 induced a significant reduction in the brain-to-blood ratio 15 and 30 min after the injection. In metabolite analysis, unchanged [{sup 11}C]FTIMD in the brain was high (98%) 30 min after the injection. In PET studies, high radioactivity levels were observed in regions with a high density of I{sub 2}R. The radioactivity levels and V{sub T} values in the brain regions were prominently reduced by 1.0 mg/kg of BU224 pretreatment as compared with control. Conclusion: [{sup 11}C]FTIMD showed specific binding to I{sub 2}Rs in rat brains with a high density of I{sub 2}R.

  15. Imaging of I2-imidazoline receptors by small-animal PET using 2-(3-fluoro-[4-11C]tolyl)-4,5-dihydro-1H-imidazole ([11C]FTIMD)

    International Nuclear Information System (INIS)

    Introduction: Imidazoline receptors (IRs) have been established as distinct receptors, and have been categorized into at least two subtypes (I1R and I2R). I2Rs are associated with depression, Alzheimer's disease, Huntington's disease and Parkinson's disease. A few positron emission tomography (PET) probes for I2Rs have been synthesized, but a selective PET probe has not been evaluated for the imaging of I2Rs by PET. We labeled a selective I2R ligand 2-(3-fluoro-4-tolyl)-4,5-dihydro-1H-imidazole (FTIMD) with 11C and performed the first imaging of I2Rs by PET using 2-(3-fluoro-[4-11C]tolyl)-4,5-dihydro-1H-imidazole ([11C]FTIMD). Methods: [11C]FTIMD was prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [11C]methyl iodide in the presence of tris(dibenzylideneacetone)dipalladium(0) and tri(o-tol)phosphine. Biodistribution was investigated in rats by tissue dissection. [11C]FTIMD metabolites were measured in brain tissues and plasma. Dynamic PET scans were acquired in rats, and the kinetic parameters estimated. Results: [11C]FTIMD was successfully synthesized with a suitable radioactivity for the injection. Co-injection with 0.1 mg/kg of cold FTIMD and BU224 induced a significant reduction in the brain-to-blood ratio 15 and 30 min after the injection. In metabolite analysis, unchanged [11C]FTIMD in the brain was high (98%) 30 min after the injection. In PET studies, high radioactivity levels were observed in regions with a high density of I2R. The radioactivity levels and VT values in the brain regions were prominently reduced by 1.0 mg/kg of BU224 pretreatment as compared with control. Conclusion: [11C]FTIMD showed specific binding to I2Rs in rat brains with a high density of I2R.

  16. Generalized metrics induced anatomical prior for MAP PET image reconstruction

    International Nuclear Information System (INIS)

    Information theoretic metrics, including mutual information (MI) and joint entropy (JE), have been investigated as priors to incorporate anatomical information in ill-posed positron emission tomography (PET) image reconstruction. These metrics are generally based on the Shannon entropy. Meanwhile, in this paper, we proposed a generalized metrics induced anatomical prior for maximum a posteriori (MAP) PET reconstruction based on the generalized Shannon entropy metrics or Tsallis entropy. For the presented prior computation, a non-parametric method was used to estimate the joint probability density of the PET and MR image. Furthermore, we also developed an one-step-advance (OSA) MAP algorithm for PET image reconstruction with the presented prior regularization. Simulation results show that the presented novel prior has significantly improved the reconstructed PET image quality. (orig.)

  17. Body-wide anatomy recognition in PET/CT images

    Science.gov (United States)

    Wang, Huiqian; Udupa, Jayaram K.; Odhner, Dewey; Tong, Yubing; Zhao, Liming; Torigian, Drew A.

    2015-03-01

    With the rapid growth of positron emission tomography/computed tomography (PET/CT)-based medical applications, body-wide anatomy recognition on whole-body PET/CT images becomes crucial for quantifying body-wide disease burden. This, however, is a challenging problem and seldom studied due to unclear anatomy reference frame and low spatial resolution of PET images as well as low contrast and spatial resolution of the associated low-dose CT images. We previously developed an automatic anatomy recognition (AAR) system [15] whose applicability was demonstrated on diagnostic computed tomography (CT) and magnetic resonance (MR) images in different body regions on 35 objects. The aim of the present work is to investigate strategies for adapting the previous AAR system to low-dose CT and PET images toward automated body-wide disease quantification. Our adaptation of the previous AAR methodology to PET/CT images in this paper focuses on 16 objects in three body regions - thorax, abdomen, and pelvis - and consists of the following steps: collecting whole-body PET/CT images from existing patient image databases, delineating all objects in these images, modifying the previous hierarchical models built from diagnostic CT images to account for differences in appearance in low-dose CT and PET images, automatically locating objects in these images following object hierarchy, and evaluating performance. Our preliminary evaluations indicate that the performance of the AAR approach on low-dose CT images achieves object localization accuracy within about 2 voxels, which is comparable to the accuracies achieved on diagnostic contrast-enhanced CT images. Object recognition on low-dose CT images from PET/CT examinations without requiring diagnostic contrast-enhanced CT seems feasible.

  18. Twelve automated thresholding methods for segmentation of PET images: a phantom study

    Science.gov (United States)

    Prieto, Elena; Lecumberri, Pablo; Pagola, Miguel; Gómez, Marisol; Bilbao, Izaskun; Ecay, Margarita; Peñuelas, Iván; Martí-Climent, Josep M.

    2012-06-01

    Tumor volume delineation over positron emission tomography (PET) images is of great interest for proper diagnosis and therapy planning. However, standard segmentation techniques (manual or semi-automated) are operator dependent and time consuming while fully automated procedures are cumbersome or require complex mathematical development. The aim of this study was to segment PET images in a fully automated way by implementing a set of 12 automated thresholding algorithms, classical in the fields of optical character recognition, tissue engineering or non-destructive testing images in high-tech structures. Automated thresholding algorithms select a specific threshold for each image without any a priori spatial information of the segmented object or any special calibration of the tomograph, as opposed to usual thresholding methods for PET. Spherical 18F-filled objects of different volumes were acquired on clinical PET/CT and on a small animal PET scanner, with three different signal-to-background ratios. Images were segmented with 12 automatic thresholding algorithms and results were compared with the standard segmentation reference, a threshold at 42% of the maximum uptake. Ridler and Ramesh thresholding algorithms based on clustering and histogram-shape information, respectively, provided better results that the classical 42%-based threshold (p < 0.05). We have herein demonstrated that fully automated thresholding algorithms can provide better results than classical PET segmentation tools.

  19. Twelve automated thresholding methods for segmentation of PET images: a phantom study

    International Nuclear Information System (INIS)

    Tumor volume delineation over positron emission tomography (PET) images is of great interest for proper diagnosis and therapy planning. However, standard segmentation techniques (manual or semi-automated) are operator dependent and time consuming while fully automated procedures are cumbersome or require complex mathematical development. The aim of this study was to segment PET images in a fully automated way by implementing a set of 12 automated thresholding algorithms, classical in the fields of optical character recognition, tissue engineering or non-destructive testing images in high-tech structures. Automated thresholding algorithms select a specific threshold for each image without any a priori spatial information of the segmented object or any special calibration of the tomograph, as opposed to usual thresholding methods for PET. Spherical 18F-filled objects of different volumes were acquired on clinical PET/CT and on a small animal PET scanner, with three different signal-to-background ratios. Images were segmented with 12 automatic thresholding algorithms and results were compared with the standard segmentation reference, a threshold at 42% of the maximum uptake. Ridler and Ramesh thresholding algorithms based on clustering and histogram-shape information, respectively, provided better results that the classical 42%-based threshold (p < 0.05). We have herein demonstrated that fully automated thresholding algorithms can provide better results than classical PET segmentation tools. (paper)

  20. Molecular cardiac PET besides FDG viability imaging; Molekulare Kardiale PET jenseits der FDG-Vitalitaetsdiagnostik

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, O.; Burchert, W. [Universitaetsklinik der Ruhr-Univ. Bochum (Germany). Inst. fuer Radiologie, Nuklearmedizin und Molekulare Bildgebung, Herz- und Diabetszentrum NRW

    2009-06-15

    Molecular cardiac non F-18-FDG PET is currently based on perfusion imaging. It is of excellent diagnostic accuracy to detect coronary artery disease (CAD) and superior to perfusion SPECT. There is also evidence for its incremental prognostic value. The unique feature of PET to measure myocardial perfusion in absolute terms and in short time periods define its impact on cardiac imaging enabling both the evaluation of early changes in CAD and the accurate characterization of multivessel disease. Currently, all available PET perfusion tracers in Europe are cyclotron products. Rb-82, a generator product, is the most frequently employed perfusion tracer in the United States and cyclotron independent. This tracer has the potential to become an alternative in Europe soon. Nowadays, PET systems are manufactured as hybrid PET-CT scanners. In oncology, hybrid imaging revealed, that the combination of functional and morphological imaging is superior to the single components. In cardiology, the integration of perfusion PET imaging with CT calcium scoring and CT anatomy of the coronary arteries represents a similar constellation. Atherosclerotic plaque evaluation by combined PET-CT technique will be one of the most promising future applications with a potential immense impact on prophylaxis, diagnosis and therapy of CAD in the future. (orig.)

  1. Performance of three-photon PET imaging: Monte Carlo simulations

    CERN Document Server

    Kacperski, K; Kacperski, Krzysztof; Spyrou, Nicholas M.

    2005-01-01

    We have recently introduced the idea of making use of three-photon positron annihilations in positron emission tomography. In this paper the basic characteristics of the three-gamma imaging in PET are studied by means of Monte Carlo simulations and analytical computations. Two typical configurations of human and small animal scanners are considered. Three-photon imaging requires high energy resolution detectors. Parameters currently attainable by CdZnTe semiconductor detectors, the technology of choice for the future development of radiation imaging, are assumed. Spatial resolution is calculated as a function of detector energy resolution and size, position in the field of view, scanner size, and the energies of the three gamma annihilation photons. Possible ways to improve the spatial resolution obtained for nominal parameters: 1.5 cm and 3.2 mm FWHM for human and small animal scanners, respectively, are indicated. Counting rates of true and random three-photon events for typical human and small animal scann...

  2. Automated movement correction for dynamic PET/CT images: Evaluation with phantom and patient data

    OpenAIRE

    Ye, H.; Wong, KP; Wardak, M; Dahlbom, M.; Kepe, V; Barrio, JR; Nelson, LD; Small, GW; Huang, SC

    2014-01-01

    Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed th...

  3. Software Solutions for Nuclear Imaging Systems in Cardiology, Small Animal Research and Education

    OpenAIRE

    Valastyán, Iván

    2010-01-01

    The sensitivity for observing physiological processes makes nuclear imaging an important tool in medical diagnostics. Different types of nuclear imaging modalities, with emphasis on the software components and image reconstructions, are presented in this thesis:  the Cardiotom for myocardial heart studies at the Karolinska University Hospital, the small animal Positron Emission Tomograph (PET) scanners for research and the SPECT, PET, spiral CT and Cardiotom demonstrators for the Royal Instit...

  4. Jet set pets: examining the zoonosis risk in animal import and travel across the European Union

    OpenAIRE

    Johnson, Nicholas

    2014-01-01

    Anthony R Fooks,1,2 Nicholas Johnson1 1Wildlife Zoonoses and Vector-Borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, 2Department of Clinical Infection, University of Liverpool, Liverpool, UK Abstract: Ownership of companion animals or pets is popular throughout the world. Unfortunately, such animals are susceptible to and potential reservoirs of zoonotic pathogens. Close proximity to and contact with pets can lead to human infections. The distribution of zoo...

  5. Kinetic modeling in PET imaging of hypoxia

    DEFF Research Database (Denmark)

    Li, Fan; Jørgensen, Jesper Tranekjær; Hansen, Anders E;

    2014-01-01

    used for non-invasive mapping of tissue oxygenation in vivo and several hypoxia specific PET tracers have been developed. Evaluation of PET data in the clinic is commonly based on visual assessment together with semiquantitative measurements e.g. standard uptake value (SUV). However, dynamic PET...

  6. An investigation of a coincidence detection system for an all-digital small animal PET scanner

    International Nuclear Information System (INIS)

    Objective: To investigate and design a coincidence detection system for an all-digital small animal PET scanner and evaluate its preliminary performance properties. Methods: This coincidence module adopted a coincidence identification mode based on singles data in list-mode.Using digital signal processing technology, energy calibration, crystal identification, timing alignment and coincidence events extraction were performed on singles data in list-mode. The obtained data could be used for image reconstruction. Results: The 13 × 13 crystal array was well recognized by the position histogram of one lutetium yttrium orthosilicate (LYSO) crystal block. In the coincidence timing histogram of the micro-Derenzo phantom, 1.36 ns full width at half maximum was obtained. The rods with a diameter of 1.2 mm were clearly displayed in the reconstructed image of the micro-Derenzo phantom. Conclusion: The coincidence module can provide satisfactory performance to meet the design needs of an all-digital small animal PET scanner. (authors)

  7. A method for small-animal PET/CT alignment calibration

    International Nuclear Information System (INIS)

    Small-animal positron-emission tomography/computed tomography (PET/CT) scanners provide anatomical and molecular imaging, which enables the joint visualization and analysis of both types of data. A proper alignment calibration procedure is essential for small-animal imaging since resolution is much higher than that in human devices. This work presents an alignment phantom and two different calibration methods that provide a reliable and repeatable measurement of the spatial geometrical alignment between the PET and the CT subsystems of a hybrid scanner. The phantom can be built using laboratory materials, and it is meant to estimate the rigid spatial transformation that aligns both modalities. It consists of three glass capillaries filled with a positron-emitter solution and positioned in a non-coplanar triangular geometry inside the system field of view. The calibration methods proposed are both based on automatic line detection, but with different approaches to calculate the transformation of the lines between both modalities. Our results show an average accuracy of the alignment estimation of 0.39 mm over the whole field of view. (note)

  8. The benefit of pets and animal-assisted therapy to the health of older individuals.

    Science.gov (United States)

    Cherniack, E Paul; Cherniack, Ariella R

    2014-01-01

    Many studies utilizing dogs, cats, birds, fish, and robotic simulations of animals have tried to ascertain the health benefits of pet ownership or animal-assisted therapy in the elderly. Several small unblinded investigations outlined improvements in behavior in demented persons given treatment in the presence of animals. Studies piloting the use of animals in the treatment of depression and schizophrenia have yielded mixed results. Animals may provide intangible benefits to the mental health of older persons, such as relief social isolation and boredom, but these have not been formally studied. Several investigations of the effect of pets on physical health suggest animals can lower blood pressure, and dog walkers partake in more physical activity. Dog walking, in epidemiological studies and few preliminary trials, is associated with lower complication risk among patients with cardiovascular disease. Pets may also have harms: they may be expensive to care for, and their owners are more likely to fall. Theoretically, zoonotic infections and bites can occur, but how often this occurs in the context of pet ownership or animal-assisted therapy is unknown. Despite the poor methodological quality of pet research after decades of study, pet ownership and animal-assisted therapy are likely to continue due to positive subjective feelings many people have toward animals. PMID:25477957

  9. The Benefit of Pets and Animal-Assisted Therapy to the Health of Older Individuals

    Directory of Open Access Journals (Sweden)

    E. Paul Cherniack

    2014-01-01

    Full Text Available Many studies utilizing dogs, cats, birds, fish, and robotic simulations of animals have tried to ascertain the health benefits of pet ownership or animal-assisted therapy in the elderly. Several small unblinded investigations outlined improvements in behavior in demented persons given treatment in the presence of animals. Studies piloting the use of animals in the treatment of depression and schizophrenia have yielded mixed results. Animals may provide intangible benefits to the mental health of older persons, such as relief social isolation and boredom, but these have not been formally studied. Several investigations of the effect of pets on physical health suggest animals can lower blood pressure, and dog walkers partake in more physical activity. Dog walking, in epidemiological studies and few preliminary trials, is associated with lower complication risk among patients with cardiovascular disease. Pets may also have harms: they may be expensive to care for, and their owners are more likely to fall. Theoretically, zoonotic infections and bites can occur, but how often this occurs in the context of pet ownership or animal-assisted therapy is unknown. Despite the poor methodological quality of pet research after decades of study, pet ownership and animal-assisted therapy are likely to continue due to positive subjective feelings many people have toward animals.

  10. PET imaging in temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Semah, F. [Service Hospitalier Frederic Joliot, DSV-CEA, 91 Orsay (France)

    2006-07-01

    The research projects on epilepsy addressed two main issues: the pathophysiology of the inter-ictal hypo-metabolism in temporal lobe epilepsy and the role of the basal ganglia in the control of seizure. Our research projects focused primarily on temporal lobe epilepsy: The pathophysiology of inter-ictal hypo-metabolism and its correlation with the epileptogenic network was investigated in patients with mesial temporal lobe epilepsy. Inter-ictal hypo-metabolism is commonly found in mesio-temporal lobe epilepsy (MTLE) but its pathophysiology remains incompletely understood. We hypothesized that metabolic changes reflect the preferential networks involved in ictal discharges. We analyzed the topography of inter-ictal hypo-metabolism according to electro-clinical patterns in 50 patients with unilateral hippocampal sclerosis (HS) and consistent features of MTLE. Based on electro-clinical correlations we identified 4 groups:1) mesial group characterized by mesial seizure onset without evidence of early spread beyond the temporal lobe; 2) anterior mesio-lateral group (AML) with early anterior spread, involving the anterior lateral temporal cortex and insulo-fronto-opercular areas; 3) widespread mesio-lateral group (WML) with widespread spread, involving both anterior and posterior lateral temporal and peri-sylvian areas; 4) bi-temporal group (BT) with early contralateral temporal spread. Results of FDG-PET imaging in each group were compared to control subjects using statistical parametric mapping software (SPM99). MRI data and surgical outcome in each group were compared to metabolic findings. Hypo-metabolism was limited to the hippocampal gyrus, the temporal pole and the insula in the mesial group. Gradual involvement of the lateral temporal cortex, the insula and the peri-sylvian areas was observed in the AML and WML groups. The BT group differed from the others by mild bi-temporal involvement, bilateral insular hypo-metabolism and longer epilepsy duration. MRI

  11. PET imaging in temporal lobe epilepsy

    International Nuclear Information System (INIS)

    The research projects on epilepsy addressed two main issues: the pathophysiology of the inter-ictal hypo-metabolism in temporal lobe epilepsy and the role of the basal ganglia in the control of seizure. Our research projects focused primarily on temporal lobe epilepsy: The pathophysiology of inter-ictal hypo-metabolism and its correlation with the epileptogenic network was investigated in patients with mesial temporal lobe epilepsy. Inter-ictal hypo-metabolism is commonly found in mesio-temporal lobe epilepsy (MTLE) but its pathophysiology remains incompletely understood. We hypothesized that metabolic changes reflect the preferential networks involved in ictal discharges. We analyzed the topography of inter-ictal hypo-metabolism according to electro-clinical patterns in 50 patients with unilateral hippocampal sclerosis (HS) and consistent features of MTLE. Based on electro-clinical correlations we identified 4 groups:1) mesial group characterized by mesial seizure onset without evidence of early spread beyond the temporal lobe; 2) anterior mesio-lateral group (AML) with early anterior spread, involving the anterior lateral temporal cortex and insulo-fronto-opercular areas; 3) widespread mesio-lateral group (WML) with widespread spread, involving both anterior and posterior lateral temporal and peri-sylvian areas; 4) bi-temporal group (BT) with early contralateral temporal spread. Results of FDG-PET imaging in each group were compared to control subjects using statistical parametric mapping software (SPM99). MRI data and surgical outcome in each group were compared to metabolic findings. Hypo-metabolism was limited to the hippocampal gyrus, the temporal pole and the insula in the mesial group. Gradual involvement of the lateral temporal cortex, the insula and the peri-sylvian areas was observed in the AML and WML groups. The BT group differed from the others by mild bi-temporal involvement, bilateral insular hypo-metabolism and longer epilepsy duration. MRI

  12. Sparsity-constrained PET image reconstruction with learned dictionaries

    Science.gov (United States)

    Tang, Jing; Yang, Bao; Wang, Yanhua; Ying, Leslie

    2016-09-01

    PET imaging plays an important role in scientific and clinical measurement of biochemical and physiological processes. Model-based PET image reconstruction such as the iterative expectation maximization algorithm seeking the maximum likelihood solution leads to increased noise. The maximum a posteriori (MAP) estimate removes divergence at higher iterations. However, a conventional smoothing prior or a total-variation (TV) prior in a MAP reconstruction algorithm causes over smoothing or blocky artifacts in the reconstructed images. We propose to use dictionary learning (DL) based sparse signal representation in the formation of the prior for MAP PET image reconstruction. The dictionary to sparsify the PET images in the reconstruction process is learned from various training images including the corresponding MR structural image and a self-created hollow sphere. Using simulated and patient brain PET data with corresponding MR images, we study the performance of the DL-MAP algorithm and compare it quantitatively with a conventional MAP algorithm, a TV-MAP algorithm, and a patch-based algorithm. The DL-MAP algorithm achieves improved bias and contrast (or regional mean values) at comparable noise to what the other MAP algorithms acquire. The dictionary learned from the hollow sphere leads to similar results as the dictionary learned from the corresponding MR image. Achieving robust performance in various noise-level simulation and patient studies, the DL-MAP algorithm with a general dictionary demonstrates its potential in quantitative PET imaging.

  13. Evaluation of New Inorganic Scintillators for Application in a Prototype Small Animal PET Scanner

    CERN Document Server

    Kuntner, C

    2003-01-01

    In the study of new pharmaceuticals as well as brain and genetic research, Positron Emission Tomography (PET) is a useful method. It has also recently entered the clinical domain in cardiology and particularly in oncology. Small animals such as mice, are often used to validate sophisticated models of human disease. High spatial resolution PET instrumentation is therefore necessary due to the reduced dimensions of the organs. Inorganic scintillators are employed in most of the diagnostic imaging devices. The ultimate performance of the PET scanner is tightly bound to the scintillation properties of the crystals. In the last years there has been an effort to develop new scintillating materials characterized by high light output, high detection efficiency and fast decay time. The most studied systems are mainly Ce3+-doped crystals such as LSO:Ce, YAP:Ce, LuAP:Ce, and recently also mixed Lux(RE3+)1-xAlO3:Ce crystals. These crystals are very attractive for medical application because of their high density (with th...

  14. PET/MRI in Oncological Imaging: State of the Art.

    Science.gov (United States)

    Bashir, Usman; Mallia, Andrew; Stirling, James; Joemon, John; MacKewn, Jane; Charles-Edwards, Geoff; Goh, Vicky; Cook, Gary J

    2015-01-01

    Positron emission tomography (PET) combined with magnetic resonance imaging (MRI) is a hybrid technology which has recently gained interest as a potential cancer imaging tool. Compared with CT, MRI is advantageous due to its lack of ionizing radiation, superior soft-tissue contrast resolution, and wider range of acquisition sequences. Several studies have shown PET/MRI to be equivalent to PET/CT in most oncological applications, possibly superior in certain body parts, e.g., head and neck, pelvis, and in certain situations, e.g., cancer recurrence. This review will update the readers on recent advances in PET/MRI technology and review key literature, while highlighting the strengths and weaknesses of PET/MRI in cancer imaging. PMID:26854157

  15. PET/MRI in Oncological Imaging: State of the Art

    Directory of Open Access Journals (Sweden)

    Usman Bashir

    2015-07-01

    Full Text Available Positron emission tomography (PET combined with magnetic resonance imaging (MRI is a hybrid technology which has recently gained interest as a potential cancer imaging tool. Compared with CT, MRI is advantageous due to its lack of ionizing radiation, superior soft-tissue contrast resolution, and wider range of acquisition sequences. Several studies have shown PET/MRI to be equivalent to PET/CT in most oncological applications, possibly superior in certain body parts, e.g., head and neck, pelvis, and in certain situations, e.g., cancer recurrence. This review will update the readers on recent advances in PET/MRI technology and review key literature, while highlighting the strengths and weaknesses of PET/MRI in cancer imaging.

  16. Use of animal waste for the production of pet food for dogs

    OpenAIRE

    Kubáčková, Anna

    2013-01-01

    The reason why I have chosen the topic named “Use of animal waste for the production of pet food for dogs“ was mainly the fact that I am interested in pet food for dogs its composition and use of animal waste for its prepare. Literature research is focused on the use of animal waste, such as slaughter waste, uneaten leftovers from the store, etc., to the production of feed dogs as pets. It can be industry food, which has three sections dry food, semi-dry food and canned or homemade BARF di...

  17. Human-animal bonds II: the role of pets in family systems and family therapy.

    Science.gov (United States)

    Walsh, Froma

    2009-12-01

    The vast majority of pet owners regard their companion animals as family members, yet the role of pets in family systems and family therapy has received little attention in research, training, and practice. This article first notes the benefits of family pets and their importance for resilience. It then examines their role in couple and family processes and their involvement in relational dynamics and tensions. Next, it addresses bereavement in the loss of a cherished pet, influences complicating grief, and facilitation of mourning and adaptation. Finally, it explores the ways that clients' pets and the use of therapists' companion animals in animal-assisted therapy can inform and enrich couple and family therapy as valuable resources in healing. PMID:19930434

  18. Spatial resolution evaluation with a pair of two four-layer DOI detectors for small animal PET scanner: jPET-RD

    Energy Technology Data Exchange (ETDEWEB)

    Nishikido, Fumihiko [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)], E-mail: funis@nirs.go.jp; Tsuda, Tomoaki [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Yoshida, Eiji; Inadama, Naoko; Shibuya, Kengo; Yamaya, Taiga [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Kitamura, Keishi [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Takahashi, Kei [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Graduate School of Science and Technology, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba-shi, Chiba 263-8522 (Japan); Ohmura, Atsushi [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Graduate School of Advanced Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169-8555 (Japan); Murayama, Hideo [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

    2008-01-01

    We are developing a small animal PET scanner, 'jPET-RD' to achieve high sensitivity as well as high spatial resolution by using four-layer depth-of-interaction (DOI) detectors. The jPET-RD is designed with two detector rings. Each detector ring is composed of six DOI detectors arranged hexagonally. The diameter of the field-of-view (FOV) is 8.8 cm, which is smaller than typical small animal PET scanners on the market now. Each detector module consists of a crystal block and a 256-channel flat panel position-sensitive photomultiplier tube. The crystal block, consisting of 32x32x4 crystal (4096 crystals, each 1.46 mmx1.46 mmx4.5 mm) and a reflector, is mounted on the 256ch FP-PMT. In this study, we evaluated the spatial resolution of reconstructed images with the evaluation system of two four-layer DOI detectors which consist of 32x32x4 LYSO (Lu: 98%, Y: 2%) crystals coupled on the 256ch FP-PMT by using RTV rubber. The spatial resolution of 1.5 mm was obtained at the center of the FOV by the filtered back projection. The spatial resolution, better than 2 mm in the whole FOV, was also achieved with DOI while the spatial resolution without DOI was degraded to 3.3 mm.

  19. FDG PET/CT imaging of lung tumor

    International Nuclear Information System (INIS)

    PET/CT imaging combines PET for functional information and CT for morphological information in a single examination, and has shown how the initial staging with lung cancer. [18F]fluoro-deoxy-glucose (FDG) PET/CT imaging has a higher diagnostic accuracy for lung cancer except so-called bronchioloalveolar carcinoma and acute inflammatory lesion such as tuberculosis, pneumonia etc, compared with the conventional diagnostic modalities. FDG PET/CT imaging can demonstrate unexpected sites of mediastinal lymph node metastases (N factor), distant metastases (M factor) in initial staging and influence treatment plans for lung cancer. Furthermore, the grade of FDG uptake on PET/CT predicts prognosis of lung cancer and evaluates tumor response to treatment. Recurrences or metastases of lung cancer, and pleural disease can be detected correctly on FDG PET/CT. It is important that interpreting physicians understand the role of FDG PET/CT in staging, assessing of treatment and observing after therapy on the multidisciplinary managements of lung cancer. The clinical applications of PET/CT are still evolving, and future researches will determine the precise role that combined metabolic and morphological imaging has to play in the management of patients with lung cancer. (author)

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

    International Nuclear Information System (INIS)

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

  1. Dynamic {sup 11}C-methionine PET analysis has an additional value for differentiating malignant tumors from granulomas: an experimental study using small animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Songji; Zhao, Yan [Hokkaido University, Department of Nuclear Medicine, Graduate School of Medicine, Sapporo (Japan); Hokkaido University, Department of Tracer Kinetics and Bioanalysis, Graduate School of Medicine, Sapporo (Japan); Kuge, Yuji; Hatano, Toshiyuki [Hokkaido University, Central Institute of Isotope Science, Sapporo (Japan); Yi, Min; Kohanawa, Masashi [Hokkaido University, Department of Advanced Medicine, Graduate School of Medicine, Sapporo (Japan); Magota, Keiichi; Tamaki, Nagara [Hokkaido University, Department of Nuclear Medicine, Graduate School of Medicine, Sapporo (Japan); Nishijima, Ken-ichi [Hokkaido University, Department of Molecular Imaging, Graduate School of Medicine, Sapporo (Japan)

    2011-10-15

    We evaluated whether the dynamic profile of L-{sup 11}C-methionine ({sup 11}C-MET) may have an additional value in differentiating malignant tumors from granulomas in experimental rat models by small animal positron emission tomography (PET). Rhodococcus aurantiacus and allogenic rat C6 glioma cells were inoculated, respectively, into the right and left calf muscles to generate a rat model bearing both granulomas and tumors (n = 6). Ten days after the inoculations, dynamic {sup 11}C-MET PET was performed by small animal PET up to 120 min after injection of {sup 11}C-MET. The next day, after overnight fasting, the rats were injected with {sup 18}F-2-deoxy-2-fluoro-D-glucose ({sup 18}F-FDG), and dynamic {sup 18}F-FDG PET was performed up to 180 min. The time-activity curves, static images, and mean standardized uptake value (SUV) in the lesions were calculated. {sup 11}C-MET uptake in the granuloma showed a slow exponential clearance after an initial distribution, while the uptake in the tumor gradually increased with time. The dynamic pattern of {sup 11}C-MET uptake in the granuloma was significantly different from that in the tumor (p < 0.001). In the static analysis of {sup 11}C-MET, visual assessment and SUV analysis could not differentiate the tumor from the granuloma in all cases, although the mean SUV in the granuloma (1.48 {+-} 0.09) was significantly lower than that in the tumor (1.72 {+-} 0.18, p < 0.01). The dynamic patterns, static images, and mean SUVs of {sup 18}F-FDG in the granuloma were similar to those in the tumor (p = NS). Dynamic {sup 11}C-MET PET has an additional value for differentiating malignant tumors from granulomatous lesions, which deserves further elucidation in clinical settings. (orig.)

  2. Development of a PET/Cerenkov-light hybrid imaging system

    International Nuclear Information System (INIS)

    Purpose: Cerenkov-light imaging is a new molecular imaging technology that detects visible photons from high-speed electrons using a high sensitivity optical camera. However, the merit of Cerenkov-light imaging remains unclear. If a PET/Cerenkov-light hybrid imaging system were developed, the merit of Cerenkov-light imaging would be clarified by directly comparing these two imaging modalities. Methods: The authors developed and tested a PET/Cerenkov-light hybrid imaging system that consists of a dual-head PET system, a reflection mirror located above the subject, and a high sensitivity charge coupled device (CCD) camera. The authors installed these systems inside a black box for imaging the Cerenkov-light. The dual-head PET system employed a 1.2 × 1.2 × 10 mm3 GSO arranged in a 33 × 33 matrix that was optically coupled to a position sensitive photomultiplier tube to form a GSO block detector. The authors arranged two GSO block detectors 10 cm apart and positioned the subject between them. The Cerenkov-light above the subject is reflected by the mirror and changes its direction to the side of the PET system and is imaged by the high sensitivity CCD camera. Results: The dual-head PET system had a spatial resolution of ∼1.2 mm FWHM and sensitivity of ∼0.31% at the center of the FOV. The Cerenkov-light imaging system's spatial resolution was ∼275μm for a 22Na point source. Using the combined PET/Cerenkov-light hybrid imaging system, the authors successfully obtained fused images from simultaneously acquired images. The image distributions are sometimes different due to the light transmission and absorption in the body of the subject in the Cerenkov-light images. In simultaneous imaging of rat, the authors found that 18F-FDG accumulation was observed mainly in the Harderian gland on the PET image, while the distribution of Cerenkov-light was observed in the eyes. Conclusions: The authors conclude that their developed PET/Cerenkov-light hybrid imaging

  3. 18F-Fluoride-PET in Skeletal Imaging

    International Nuclear Information System (INIS)

    Bone scintigraphy using 99mTc-labeled phosphate agents has long been the standard evaluation method for whole skeletal system. However, recent shortage of 99mTc supply and advanced positron emission tomography (PET) technology evoked the attention to surrogate radiopharmaceuticals and imaging modalities for bone. Actually, fluorine-18 (18F) was the first bone seeking radiotracer before the introduction of 99mTc-labeled agents even though its clinical application failed to become pervasive anymore after the rapid spread of Anger type gamma camera systems in early 1970s. However, rapidly developed PET technology made us refocus on the usefulness of 18F as a PET tracer. Early study comparing 18F-Na PET scan and planar bone scintigraphy reported that PET has higher sensitivity and specificity in the diagnosis of metastatic bone lesions than planar bone scan. Subsequent reports comparing between PET and both planar and SPECT bone image also revealed better results of PET scan in similar study groups. Rapid clinical application of PET/CT also accumulated considerable amount of experiences in skeletal evaluation and this modality is known to have better diagnostic power than stand alone PET system as well as bone scan. Furthermore 18F-Na PET/CT revealed better or at least equal results in detection of primary and metastatic bone lesions compared with CT and MRI. Therefore, it is obvious that 18F-Na PET/CT has potential to become new imaging modality for practical skeletal evaluation so continuous and careful evaluation of this modality and radiopharmaceutical must be required

  4. PET Imaging and biodistribution of chemically modified bacteriophage MS2.

    Science.gov (United States)

    Farkas, Michelle E; Aanei, Ioana L; Behrens, Christopher R; Tong, Gary J; Murphy, Stephanie T; O'Neil, James P; Francis, Matthew B

    2013-01-01

    The fields of nanotechnology and medicine have merged in the development of new imaging and drug delivery agents based on nanoparticle platforms. As one example, a mutant of bacteriophage MS2 can be differentially modified on the exterior and interior surfaces for the concurrent display of targeting functionalities and payloads, respectively. In order to realize their potential for use in in vivo applications, the biodistribution and circulation properties of this class of agents must first be investigated. A means of modulating and potentially improving the characteristics of nanoparticle agents is the appendage of PEG chains. Both MS2 and MS2-PEG capsids possessing interior DOTA chelators were labeled with (64)Cu and injected intravenously into mice possessing tumor xenografts. Dynamic imaging of the agents was performed using PET-CT on a single animal per sample, and the biodistribution at the terminal time point (24 h) was assessed by gamma counting of the organs ex vivo for 3 animals per agent. Compared to other viral capsids of similar size, the MS2 agents showed longer circulation times. Both MS2 and MS2-PEG bacteriophage behaved similarly, although the latter agent showed significantly less uptake in the spleen. This effect may be attributed to the ability of the PEG chains to mask the capsid charge. Although the tumor uptake of the agents may result from the enhanced permeation and retention (EPR) effect, selective tumor imaging may be achieved in the future by using exterior targeting groups. PMID:23214968

  5. PET IMAGING STUDIES IN DRUG ABUSE RESEARCH.

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J.S.; Volkow, N.D.; Ding, Y.S.; Logan, J.; Wang, G.J.

    2001-01-29

    There is overwhelming evidence that addiction is a disease of the brain (Leshner, 1997). Yet public perception that addiction is a reflection of moral weakness or a lack of willpower persists. The insidious consequence of this perception is that we lose sight of the fact that there are enormous medical consequences of addiction including the fact that a large fraction of the total deaths from cancer and heart disease are caused by smoking addiction. Ironically the medical school that educates physicians in addiction medicine and the cancer hospital that has a smoking cessation clinic are vanishingly rare and efforts at harm reduction are frequently met with a public indignation. Meanwhile the number of people addicted to substances is enormous and increasing particularly the addictions to cigarettes and alcohol. It is particularly tragic that addiction usually begins in adolescence and becomes a chronic relapsing problem and there are basically no completely effective treatments. Clearly we need to understand how drugs of abuse affect the brain and we need to be creative in using this information to develop effective treatments. Imaging technologies have played a major role in the conceptualization of addiction as a disease of the brain (Fowler et al., 1998a; Fowler et al., 1999a). New knowledge has been driven by advances in radiotracer design and chemistry and positron emission tomography (PET) instrumentation and the integration of these scientific tools with the tools of biochemistry, pharmacology and medicine. This topic cuts across the medical specialties of neurology, psychiatry, cancer and heart disease because of the high medical, social and economic toll that drugs of abuse, including and especially the legal drugs, cigarettes and alcohol, take on society. In this chapter we will begin by highlighting the important role that chemistry has played in making it possible to quantitatively image the movement of drugs as well as their effects on the human brain

  6. Ultrasonography Fused with PET-CT Hybrid Imaging

    DEFF Research Database (Denmark)

    Udesen, Jesper; Ewertsen, Caroline; Gran, Fredrik;

    2011-01-01

    We present a method with fusion of images of three modalities 18F-FDG PET, CT, and 3-D ultrasound (US) applied to imaging of the anal canal and the rectum. To obtain comparable geometries in the three imaging modalities, a plexiglas rod, with the same dimensions as the US transducer, is placed in...... the anal canal prior to the PET-CT examination. The method is based on manual co-registration of PET-CT images and 3-D US images. The three-modality imaging of the rectum-anal canal may become useful as a supplement to conventional imaging in the external radiation therapy in the treatment of anal....... Three-modality imaging may also be used in certain other diagnostic or therapeutic fields....

  7. Imaging performance of LabPET APD-based digital PET scanners for pre-clinical research

    International Nuclear Information System (INIS)

    The LabPET is an avalanche photodiode (APD) based digital PET scanner with quasi-individual detector read-out and highly parallel electronic architecture for high-performance in vivo molecular imaging of small animals. The scanner is based on LYSO and LGSO scintillation crystals (2×2×12/14 mm3), assembled side-by-side in phoswich pairs read out by an APD. High spatial resolution is achieved through the individual and independent read-out of an individual APD detector for recording impinging annihilation photons. The LabPET exists in three versions, LabPET4 (3.75 cm axial length), LabPET8 (7.5 cm axial length) and LabPET12 (11.4 cm axial length). This paper focuses on the systematic characterization of the three LabPET versions using two different energy window settings to implement a high-efficiency mode (250–650 keV) and a high-resolution mode (350–650 keV) in the most suitable operating conditions. Prior to measurements, a global timing alignment of the scanners and optimization of the APD operating bias have been carried out. Characteristics such as spatial resolution, absolute sensitivity, count rate performance and image quality have been thoroughly investigated following the NEMA NU 4-2008 protocol. Phantom and small animal images were acquired to assess the scanners' suitability for the most demanding imaging tasks in preclinical biomedical research. The three systems achieve the same radial FBP spatial resolution at 5 mm from the field-of-view center: 1.65/3.40 mm (FWHM/FWTM) for an energy threshold of 250 keV and 1.51/2.97 mm for an energy threshold of 350 keV. The absolute sensitivity for an energy window of 250–650 keV is 1.4%/2.6%/4.3% for LabPET4/8/12, respectively. The best count rate performance peaking at 362 kcps is achieved by the LabPET12 with an energy window of 250–650 keV and a mouse phantom (2.5 cm diameter) at an activity of 2.4 MBq ml−1. With the same phantom, the scatter fraction for all scanners is about 17

  8. Facile Fabrication of Animal-Specific Positioning Molds For Multi-modality Molecular Imaging

    International Nuclear Information System (INIS)

    Recently multi-modal imaging system has become widely adopted in molecular imaging. We tried to fabricate animal-specific positioning molds for PET/MR fusion imaging using easily available molding clay and rapid foam. The animal-specific positioning molds provide immobilization and reproducible positioning of small animal. Herein, we have compared fiber-based molding clay with rapid foam in fabricating the molds of experimental animal. The round bottomed-acrylic frame, which fitted into microPET gantry, was prepared at first. The experimental mice was anesthetized and placed on the mold for positioning. Rapid foam and fiber-based clay were used to fabricate the mold. In case of both rapid foam and the clay, the experimental animal needs to be pushed down smoothly into the mold for positioning. However, after the mouse was removed, the fabricated clay needed to be dried completely at 60 .deg. C in oven overnight for hardening. Four sealed pipe tips containing [18F]FDG solution were used as fiduciary markers. After injection of [18F]FDG via tail vein, microPET scanning was performed. Successively, MRI scanning was followed in the same animal. Animal-specific positioning molds were fabricated using rapid foam and fiber-based molding clay for multimodality imaging. Functional and anatomical images were obtained with microPET and MRI, respectively. The fused PET/MR images were obtained using freely available AMIDE program. Animal-specific molds were successfully prepared using easily available rapid foam, molding clay and disposable pipet tips. Thanks to animal-specific molds, fusion images of PET and MR were co-registered with negligible misalignment

  9. Cardiovascular hybrid imaging using PET/MRI; Kardiovaskulaere Hybridbildgebung mit PET/MRT

    Energy Technology Data Exchange (ETDEWEB)

    Nensa, Felix; Schlosser, Thomas [Universitaetsklinikum Essen (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie und Neuroradiologie

    2014-12-15

    The following overview provides a summary of the state of the art and research as well as potential clinical applications of cardiovascular PET/MR imaging. PET/MRI systems have been clinically available for a few years, and their use in cardiac imaging has been successfully demonstrated. At this period in time, some of the technical difficulties that arose at the beginning have been solved; in particular with respect to MRI-based attenuation correction, caution should be exercised with PET quantification. In addition, many promising technical options are still in the developmental stage, such as MRI-based motion correction of PET data resulting from simultaneous MR acquisition, and are not yet available for cardiovascular imaging. On the other hand, PET/MRI has been used to demonstrate significant pathologies such as acute and chronic myocardial infarction, myocarditis or cardiac sarcoidosis; future applications in clinical routine or within studies appear to be possible. In coming years additional studies will have to be performed to prove diagnostic gain at a reasonable cost-benefit ratio before valid conclusions are possible regarding the clinical utility and future of cardiovascular PET/MR imaging.

  10. Prevalence, species distribution and antimicrobial resistance patterns of methicillin-resistant staphylococci in Lithuanian pet animals

    OpenAIRE

    Ruzauskas, Modestas; Couto, Natacha; Kerziene, Sigita; Siugzdiniene, Rita; Klimiene, Irena; Virgailis, Marius; Pomba, Constança

    2015-01-01

    Background The bacterial genus Staphylococcus consists of many species that causes infections in pet animals. Antimicrobial resistant staphylococci cause infections that are difficult to treat and they are important from the point of one health perspective. The aim of this study was to determine the prevalence of methicillin-resistant Staphylococcus (MRS) species, including methicillin-resistant S. aureus (MRSA) in diseased pet animals (Group A) and kennel dogs (Group B) in Lithuania and to c...

  11. Dual modality CT/PET imaging in lung cancer staging

    International Nuclear Information System (INIS)

    Purpose: To compare the diagnostic capability of PET-HCT image fusion and helical computed tomography (HCT) for nodal and distant metastases detection in patients with lung cancer. Material and methods: Between February, 2003 and March, 2004 sixty-six consecutive lung cancer patients (45 men and 21 women, mean ages: 63 years old, range: 38 to 96 years old) who underwent HCT and PET-HCT fusion imaging were evaluated retrospectively. All patients had histological confirmation of lung cancer and a definitive diagnosis established on the basis of pathology results and/or clinical follow-up. Results: For global nodal staging (hilar and mediastinal) HCT showed a sensitivity, specificity, positive predictive value and negative predictive value of 72%, 47%, 62% and 58% respectively, versus 94%, 77%, 83% and 92% corresponding to PET-HCT examination. For assessment of advanced nodal stage (N3) PET-HCT showed values of 92%, 100%, 100% and 98% respectively. For detection of distant metastasis, HCT alone had values of 67%, 93%, 84% and 83% respectively versus 100%, 98%, 96% and 100% for the PET-HCT fusion imaging. In 20 (30%) patients under-staged or over-staged on the basis of HCT results, PET-HCT allowed accurate staging. Conclusions: PET-HCT fusion imaging was more effective than HCT alone for nodal and distant metastasis detection and oncology staging. (author)

  12. Assessment of oxidative metabolism in Brown Fat using PET imaging

    OpenAIRE

    Otto eMuzik; Mangner, Thomas J.; Granneman, James G.

    2012-01-01

    Objective: Although it has been believed that brown adipose tissue (BAT) depots disappear shortly after the perinatal period in humans, PET imaging using the glucose analog FDG has shown unequivocally the existence of functional BAT in humans. The objective of this study was to determine, using dynamic oxygen-15 (15O) PET imaging, to what extent BAT thermogenesis is activated in adults during cold stress and to establish the relationship between BAT oxidative metabolism and FDG tracer uptake....

  13. Assessment of Oxidative Metabolism in Brown Fat Using PET Imaging

    OpenAIRE

    Muzik, Otto; Mangner, Thomas J.; Granneman, James G.

    2012-01-01

    Objective: Although it has been believed that brown adipose tissue (BAT) depots disappear shortly after the perinatal period in humans, positron emission tomography (PET) imaging using the glucose analog 18F-deoxy-d-glucose (FDG) has shown unequivocally the existence of functional BAT in humans, suggesting that most humans have some functional BAT. The objective of this study was to determine, using dynamic oxygen-15 (15O) PET imaging, to what extent BAT thermogenesis is activated in adults d...

  14. Fluorine-18 NaF PET imaging of child abuse

    Energy Technology Data Exchange (ETDEWEB)

    Drubach, Laura A. [Children' s Hospital Boston and Harvard Medical School, Department of Radiology, Division of Nuclear Medicine/PET, Boston, MA (United States); Sapp, Mark.V. [School of Osteopathic Medicine, Child Abuse Research Education and Services (CARES) Institute University of Medicine and Dentistry of New Jersey, New Jersey (United States); Laffin, Stephen [Children' s Hospital Boston, Department of Radiology, Division of Nuclear Medicine/PET, Boston, MA (United States); Kleinman, Paul K. [Children' s Hospital Boston and Harvard Medical School, Department of Radiology, Division of Musculoskeletal Imaging, Boston, MA (United States)

    2008-07-15

    We describe the use of {sup 18}F-NaF positron emission tomography (PET) whole-body imaging for the evaluation of skeletal trauma in a case of suspected child abuse. To our knowledge, 18F NaF PET has not been used in the past for the evaluation of child abuse. In our patient, this technique detected all sites of trauma shown by initial and follow-up skeletal surveys, including bilateral metaphyseal fractures of the proximal humeri. Fluorine-18 NaF PET has potential advantage over Tc-99m-labeled methylene diphosphonate (MDP) based upon superior image contrast and spatial resolution. (orig.)

  15. Fluorine-18 NaF PET imaging of child abuse

    International Nuclear Information System (INIS)

    We describe the use of 18F-NaF positron emission tomography (PET) whole-body imaging for the evaluation of skeletal trauma in a case of suspected child abuse. To our knowledge, 18F NaF PET has not been used in the past for the evaluation of child abuse. In our patient, this technique detected all sites of trauma shown by initial and follow-up skeletal surveys, including bilateral metaphyseal fractures of the proximal humeri. Fluorine-18 NaF PET has potential advantage over Tc-99m-labeled methylene diphosphonate (MDP) based upon superior image contrast and spatial resolution. (orig.)

  16. Validation of a small-animal PET simulation using GAMOS: a GEANT4-based framework

    Science.gov (United States)

    Cañadas, M.; Arce, P.; Rato Mendes, P.

    2011-01-01

    Monte Carlo-based modelling is a powerful tool to help in the design and optimization of positron emission tomography (PET) systems. The performance of these systems depends on several parameters, such as detector physical characteristics, shielding or electronics, whose effects can be studied on the basis of realistic simulated data. The aim of this paper is to validate a comprehensive study of the Raytest ClearPET small-animal PET scanner using a new Monte Carlo simulation platform which has been developed at CIEMAT (Madrid, Spain), called GAMOS (GEANT4-based Architecture for Medicine-Oriented Simulations). This toolkit, based on the GEANT4 code, was originally designed to cover multiple applications in the field of medical physics from radiotherapy to nuclear medicine, but has since been applied by some of its users in other fields of physics, such as neutron shielding, space physics, high energy physics, etc. Our simulation model includes the relevant characteristics of the ClearPET system, namely, the double layer of scintillator crystals in phoswich configuration, the rotating gantry, the presence of intrinsic radioactivity in the crystals or the storage of single events for an off-line coincidence sorting. Simulated results are contrasted with experimental acquisitions including studies of spatial resolution, sensitivity, scatter fraction and count rates in accordance with the National Electrical Manufacturers Association (NEMA) NU 4-2008 protocol. Spatial resolution results showed a discrepancy between simulated and measured values equal to 8.4% (with a maximum FWHM difference over all measurement directions of 0.5 mm). Sensitivity results differ less than 1% for a 250-750 keV energy window. Simulated and measured count rates agree well within a wide range of activities, including under electronic saturation of the system (the measured peak of total coincidences, for the mouse-sized phantom, was 250.8 kcps reached at 0.95 MBq mL-1 and the simulated peak was

  17. Ultrasonography Fused with PET-CT Hybrid Imaging

    DEFF Research Database (Denmark)

    Udesen, Jesper; Ewertsen, Caroline; Gran, Fredrik; Fogh Christensen, Anders; Kjaer-Kristoffersen, Flemming; Engelholm, Svend Aage; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    the anal canal prior to the PET-CT examination. The method is based on manual co-registration of PET-CT images and 3-D US images. The three-modality imaging of the rectum-anal canal may become useful as a supplement to conventional imaging in the external radiation therapy in the treatment of anal......We present a method with fusion of images of three modalities 18F-FDG PET, CT, and 3-D ultrasound (US) applied to imaging of the anal canal and the rectum. To obtain comparable geometries in the three imaging modalities, a plexiglas rod, with the same dimensions as the US transducer, is placed in...... cancer, where the precise delineation of a tumor is crucial to avoid damage from radiation therapy to the healthy tissue surrounding it. The technique is still in a phase of development, and the demands for integration different company software systems are significant before commercial application...

  18. The Benefit of Pets and Animal-Assisted Therapy to the Health of Older Individuals

    OpenAIRE

    E. Paul Cherniack; Cherniack, Ariella R.

    2014-01-01

    Many studies utilizing dogs, cats, birds, fish, and robotic simulations of animals have tried to ascertain the health benefits of pet ownership or animal-assisted therapy in the elderly. Several small unblinded investigations outlined improvements in behavior in demented persons given treatment in the presence of animals. Studies piloting the use of animals in the treatment of depression and schizophrenia have yielded mixed results. Animals may provide intangible benefits to the mental health...

  19. Complicated grief and posttraumatic stress disorder in humans' response to the death of pets/animals.

    Science.gov (United States)

    Adrian, Julie A Luiz; Deliramich, Aimee N; Frueh, B Christopher

    2009-01-01

    The present exploratory project represents a cross-sectional study designed to determine the percentage of people reporting significant symptoms of complicated grief (CG) and/or posttraumatic stress disorder (PTSD) in response to the death of companion pets/animals. Human participants (N = 106) were sampled from a veterinary clinic. Fifty-two percent of participants had lost one to three pets from natural causes, 60% had never lost a pet to euthanasia, and 37% had lost one to three pets to euthanasia. The study suggests that many people experience significant attachment to their pets/animals and experience significant features of grief reactions (about 20%) after the death of a pet/animal. However, the percentage of people experiencing major pathological disruption is relatively low (pets/animals and last 6 months or more for about 30% of those sampled. Severe pathological reactions do occur but are quite rare among human survivors. Implications for mental health clinicians working with affected populations are discussed. PMID:19807222

  20. First PET Center in Mexico: the power of molecular imaging

    International Nuclear Information System (INIS)

    Positron Emission Tomography (PET) is a non-invasive diagnostic imaging technique modality. It represents the forefront of medical images and was developed as a quantitative technique for imaging biochemical and physiological processes in the human body. PET is unique because it produces images of the body's basic biochemistry or function. Traditional diagnostic techniques such as x-rays, CT scans or MRI, produce images of the body's anatomy or structure. The premise with these techniques is that the change in anatomy or structure that occurs with disease can be seen. However, biochemical processes are also altered with disease and may occur before there is a change gross anatomy. PET is an imaging technique that is used to visualize some of these processes. The development of PET as we know it today began in 1974 with the development of a single ring detector system by Phelps et al. Today, over 350 PET scanners are in use in the world, mainly in the USA (over 140), Europe (particularly in the Anglo-Saxon countries and France) and Japan. Many of these facilities also have their own cyclotron to produce the positron emitters. In the Southern hemisphere, only Australia, Argentina. and recently Mexico, have a very small number of PET facilities. (Author)

  1. Dynamic 11C-methionine PET analysis has an additional value for differentiating malignant tumors from granulomas: an experimental study using small animal PET

    International Nuclear Information System (INIS)

    We evaluated whether the dynamic profile of L-11C-methionine (11C-MET) may have an additional value in differentiating malignant tumors from granulomas in experimental rat models by small animal positron emission tomography (PET). Rhodococcus aurantiacus and allogenic rat C6 glioma cells were inoculated, respectively, into the right and left calf muscles to generate a rat model bearing both granulomas and tumors (n = 6). Ten days after the inoculations, dynamic 11C-MET PET was performed by small animal PET up to 120 min after injection of 11C-MET. The next day, after overnight fasting, the rats were injected with 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG), and dynamic 18F-FDG PET was performed up to 180 min. The time-activity curves, static images, and mean standardized uptake value (SUV) in the lesions were calculated. 11C-MET uptake in the granuloma showed a slow exponential clearance after an initial distribution, while the uptake in the tumor gradually increased with time. The dynamic pattern of 11C-MET uptake in the granuloma was significantly different from that in the tumor (p 11C-MET, visual assessment and SUV analysis could not differentiate the tumor from the granuloma in all cases, although the mean SUV in the granuloma (1.48 ± 0.09) was significantly lower than that in the tumor (1.72 ± 0.18, p 18F-FDG in the granuloma were similar to those in the tumor (p = NS). Dynamic 11C-MET PET has an additional value for differentiating malignant tumors from granulomatous lesions, which deserves further elucidation in clinical settings. (orig.)

  2. FDG PET/CT imaging as a biomarker in lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Meignan, Michel; Itti, Emmanuel [Hopitaux Universitaires Henri Mondor, Paris-Est Creteil University, LYSA Imaging, Department of Nuclear Medicine, Creteil (France); Gallamini, Andrea [Nice University, Research, Innovation and Statistic Department, Antoine Lacassagne Cancer Center, Nice (France); Scientific Research Committee, S. Croce Hospital, Cuneo (Italy); Younes, Anas [Memorial Sloan Kettering Cancer Center, Lymphoma Service, New York, NY (United States)

    2015-04-01

    FDG PET/CT has changed the management of FDG-avid lymphoma and is now recommended as the imaging technique of choice for staging and restaging. The need for tailoring therapy to reduce toxicity in patients with a favourable outcome and for improving treatment in those with high-risk factors requires accurate diagnostic methods and a new prognostic algorithm to identify different risk categories. New drugs are used in relapsed/refractory patients. The role of FDG PET/CT as a biomarker in this context is summarized in this review. New trends in FDG metabolic imaging in lymphoma are addressed including metabolic tumour volume measurement at staging and integrative PET which combines PET data with clinical and molecular markers or other imaging techniques. The quantitative approach for response assessment which is under investigation and is used in large ongoing trials is compared with visual criteria. The place of FDG in the era of targeted therapy is discussed. (orig.)

  3. Towards optimal imaging with PET: an in silico feasibility study

    International Nuclear Information System (INIS)

    The efficacy of Positron Emission Tomography (PET) imaging relies fundamentally on the ability of the system to accurately identify true coincidence events. With existing systems, this is currently accomplished with an energy acceptance criterion followed by correction techniques to remove suspected false coincidence events. These corrections generally result in signal and contrast loss and thus limit the PET system’s ability to achieve optimum image quality. A key property of annihilation radiation is that the photons are polarised with respect to each other. This polarisation correlation offers a potentially powerful discriminator, independent of energy, to accurately identify true events. In this proof of concept study, we investigate how photon polarisation information can be exploited in PET imaging by developing a method to discriminate true coincidences using the polarisation correlation of annihilation pairs. We implement this method using a Geant4 PET simulation of a GE Advance/Discovery LS system and demonstrate the potential advantages of the polarisation coincidence selection method over a standard energy criterion method. Current PET ring detectors are not capable of exploiting the polarisation correlation of the photon pairs. Compton PET systems, however are promising candidates for this application. We demonstrate the feasibility of a two-component Compton camera system in identifying true coincidences with Monte Carlo simulations. Our study demonstrates the potential of improving signal gain using polarisation, particularly for high photon emission rates. We also demonstrate the ability of the Compton camera at exploiting this polarisation correlation in PET. (paper)

  4. Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part II. In Vivo Imaging of Bone Marrow Stromal Cells in Swine with PET/CT and MR Imaging.

    Science.gov (United States)

    Parashurama, Natesh; Ahn, Byeong-Cheol; Ziv, Keren; Ito, Ken; Paulmurugan, Ramasamy; Willmann, Jürgen K; Chung, Jaehoon; Ikeno, Fumiaki; Swanson, Julia C; Merk, Denis R; Lyons, Jennifer K; Yerushalmi, David; Teramoto, Tomohiko; Kosuge, Hisanori; Dao, Catherine N; Ray, Pritha; Patel, Manishkumar; Chang, Ya-Fang; Mahmoudi, Morteza; Cohen, Jeff Eric; Goldstone, Andrew Brooks; Habte, Frezghi; Bhaumik, Srabani; Yaghoubi, Shahriar; Robbins, Robert C; Dash, Rajesh; Yang, Phillip C; Brinton, Todd J; Yock, Paul G; McConnell, Michael V; Gambhir, Sanjiv S

    2016-09-01

    Purpose To quantitatively determine the limit of detection of marrow stromal cells (MSC) after cardiac cell therapy (CCT) in swine by using clinical positron emission tomography (PET) reporter gene imaging and magnetic resonance (MR) imaging with cell prelabeling. Materials and Methods Animal studies were approved by the institutional administrative panel on laboratory animal care. Seven swine received 23 intracardiac cell injections that contained control MSC and cell mixtures of MSC expressing a multimodality triple fusion (TF) reporter gene (MSC-TF) and bearing superparamagnetic iron oxide nanoparticles (NP) (MSC-TF-NP) or NP alone. Clinical MR imaging and PET reporter gene molecular imaging were performed after intravenous injection of the radiotracer fluorine 18-radiolabeled 9-[4-fluoro-3-(hydroxyl methyl) butyl] guanine ((18)F-FHBG). Linear regression analysis of both MR imaging and PET data and nonlinear regression analysis of PET data were performed, accounting for multiple injections per animal. Results MR imaging showed a positive correlation between MSC-TF-NP cell number and dephasing (dark) signal (R(2) = 0.72, P = .0001) and a lower detection limit of at least approximately 1.5 × 10(7) cells. PET reporter gene imaging demonstrated a significant positive correlation between MSC-TF and target-to-background ratio with the linear model (R(2) = 0.88, P = .0001, root mean square error = 0.523) and the nonlinear model (R(2) = 0.99, P = .0001, root mean square error = 0.273) and a lower detection limit of 2.5 × 10(8) cells. Conclusion The authors quantitatively determined the limit of detection of MSC after CCT in swine by using clinical PET reporter gene imaging and clinical MR imaging with cell prelabeling. (©) RSNA, 2016 Online supplemental material is available for this article. PMID:27332865

  5. Improved Image Fusion in PET/CT Using Hybrid Image Reconstruction and Super-Resolution

    OpenAIRE

    Kennedy, John A.; Ora Israel; Alex Frenkel; Rachel Bar-Shalom; Haim Azhari

    2007-01-01

    Purpose. To provide PET/CT image fusion with an improved PET resolution and better contrast ratios than standard reconstructions. Method. Using a super-resolution algorithm, several PET acquisitions were combined to improve the resolution. In addition, functional PET data was smoothed with a hybrid computed tomography algorithm (HCT), in which anatomical edge information taken from the CT was employed to retain sharper edges. The combined HCT and super-resolution technique were evaluated in p...

  6. Spatial resolution recovery utilizing multi-ray tracing and graphic processing unit in PET image reconstruction

    International Nuclear Information System (INIS)

    Depth-of-interaction (DOI) poses a major challenge for a PET system to achieve uniform spatial resolution across the field-of-view, particularly for small animal and organ-dedicated PET systems. In this work, we implemented an analytical method to model system matrix for resolution recovery, which was then incorporated in PET image reconstruction on a graphical processing unit platform, due to its parallel processing capacity. The method utilizes the concepts of virtual DOI layers and multi-ray tracing to calculate the coincidence detection response function for a given line-of-response. The accuracy of the proposed method was validated for a small-bore PET insert to be used for simultaneous PET/MR breast imaging. In addition, the performance comparisons were studied among the following three cases: 1) no physical DOI and no resolution modeling; 2) two physical DOI layers and no resolution modeling; and 3) no physical DOI design but with a different number of virtual DOI layers. The image quality was quantitatively evaluated in terms of spatial resolution (full-width-half-maximum and position offset), contrast recovery coefficient and noise. The results indicate that the proposed method has the potential to be used as an alternative to other physical DOI designs and achieve comparable imaging performances, while reducing detector/system design cost and complexity. (paper)

  7. Spatial resolution recovery utilizing multi-ray tracing and graphic processing unit in PET image reconstruction

    Science.gov (United States)

    Liang, Yicheng; Peng, Hao

    2015-02-01

    Depth-of-interaction (DOI) poses a major challenge for a PET system to achieve uniform spatial resolution across the field-of-view, particularly for small animal and organ-dedicated PET systems. In this work, we implemented an analytical method to model system matrix for resolution recovery, which was then incorporated in PET image reconstruction on a graphical processing unit platform, due to its parallel processing capacity. The method utilizes the concepts of virtual DOI layers and multi-ray tracing to calculate the coincidence detection response function for a given line-of-response. The accuracy of the proposed method was validated for a small-bore PET insert to be used for simultaneous PET/MR breast imaging. In addition, the performance comparisons were studied among the following three cases: 1) no physical DOI and no resolution modeling; 2) two physical DOI layers and no resolution modeling; and 3) no physical DOI design but with a different number of virtual DOI layers. The image quality was quantitatively evaluated in terms of spatial resolution (full-width-half-maximum and position offset), contrast recovery coefficient and noise. The results indicate that the proposed method has the potential to be used as an alternative to other physical DOI designs and achieve comparable imaging performances, while reducing detector/system design cost and complexity.

  8. Quantitative Comparison of Y-90 and Ge-68 PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sangkeun; Kwak, Shin Hye; Lee, Jeong A; Song, Han Kyeol; Kang, Joo Hyun; Lim, Sang Moo; KIm, Kyeong Min [Korea Institute of Raiological and Medical Sciences, Seoul (Korea, Republic of); Jeong, Su Young [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2014-05-15

    The purpose of this study was to assess statistical characteristics and to improve count rate of image for enhancing Y-90 image quality by using non-parametric bootstrap method. The results showed that Y-90 PET image can be improved using non-parametric bootstrap method. PET data was able to be improved using non-parametric bootstrap method and it was verified with showing improved prompts rate. Y-90 PET image quality was improved and bias indicated that the bootstrapped image was more similar to the gold standard than other images. The non-parametric bootstrap method will be useful tool for enhancing Y-90 PET image and it will be expected to reduce time for acquisition and to elevate performance for diagnosis and treatment. Yttrium-90 (Y-90) radioembolization is one of the treatment methods unrespectable stage of hepatocellular carcinoma (HCC) and metastatic colon cancer to the liver. However, Y-90 radioembolization is a catheter-based therapy that delivers internal radiation to tumors, it results in greater radiation exposure to the tumors than using external radiation. Also, unlike other current therapies for the treatment of unresectable liver tumors, Y-90 radioembolization is much less often associated with toxicities such as abdominal pain, fever, nausea, and vomiting. Therefore Y-90 has been received much interest and studied by many researchers. Imaging of Y-90 has been conducted using most commonly gamma camera but quantitative PET imaging is required due to low sensitivity and resolution. Y-90 imaging is generally performed with SPECT by Bremsstrahlung photons. Unfortunately, the low image quality due to the nature of the Bremsstrahlung photon limits the quantitative accuracy of Y-90 SPECT. To overcome this limitation in SPECT imaging, Y-90 PET has been suggested as an alternative.

  9. Quantitative Comparison of Y-90 and Ge-68 PET imaging

    International Nuclear Information System (INIS)

    The purpose of this study was to assess statistical characteristics and to improve count rate of image for enhancing Y-90 image quality by using non-parametric bootstrap method. The results showed that Y-90 PET image can be improved using non-parametric bootstrap method. PET data was able to be improved using non-parametric bootstrap method and it was verified with showing improved prompts rate. Y-90 PET image quality was improved and bias indicated that the bootstrapped image was more similar to the gold standard than other images. The non-parametric bootstrap method will be useful tool for enhancing Y-90 PET image and it will be expected to reduce time for acquisition and to elevate performance for diagnosis and treatment. Yttrium-90 (Y-90) radioembolization is one of the treatment methods unrespectable stage of hepatocellular carcinoma (HCC) and metastatic colon cancer to the liver. However, Y-90 radioembolization is a catheter-based therapy that delivers internal radiation to tumors, it results in greater radiation exposure to the tumors than using external radiation. Also, unlike other current therapies for the treatment of unresectable liver tumors, Y-90 radioembolization is much less often associated with toxicities such as abdominal pain, fever, nausea, and vomiting. Therefore Y-90 has been received much interest and studied by many researchers. Imaging of Y-90 has been conducted using most commonly gamma camera but quantitative PET imaging is required due to low sensitivity and resolution. Y-90 imaging is generally performed with SPECT by Bremsstrahlung photons. Unfortunately, the low image quality due to the nature of the Bremsstrahlung photon limits the quantitative accuracy of Y-90 SPECT. To overcome this limitation in SPECT imaging, Y-90 PET has been suggested as an alternative

  10. Attenuation correction for freely moving small animal brain PET studies based on a virtual scanner geometry

    Science.gov (United States)

    Angelis, G. I.; Kyme, A. Z.; Ryder, W. J.; Fulton, R. R.; Meikle, S. R.

    2014-10-01

    Attenuation correction in positron emission tomography brain imaging of freely moving animals is a very challenging problem since the torso of the animal is often within the field of view and introduces a non negligible attenuating factor that can degrade the quantitative accuracy of the reconstructed images. In the context of unrestrained small animal imaging, estimation of the attenuation correction factors without the need for a transmission scan is highly desirable. An attractive approach that avoids the need for a transmission scan involves the generation of the hull of the animal’s head based on the reconstructed motion corrected emission images. However, this approach ignores the attenuation introduced by the animal’s torso. In this work, we propose a virtual scanner geometry which moves in synchrony with the animal’s head and discriminates between those events that traversed only the animal’s head (and therefore can be accurately compensated for attenuation) and those that might have also traversed the animal’s torso. For each recorded pose of the animal’s head a new virtual scanner geometry is defined and therefore a new system matrix must be calculated leading to a time-varying system matrix. This new approach was evaluated on phantom data acquired on the microPET Focus 220 scanner using a custom-made phantom and step-wise motion. Results showed that when the animal’s torso is within the FOV and not appropriately accounted for during attenuation correction it can lead to bias of up to 10% . Attenuation correction was more accurate when the virtual scanner was employed leading to improved quantitative estimates (bias introduced by the extraneous compartment. Although the proposed method requires increased computational resources, it can provide a reliable approach towards quantitatively accurate attenuation correction for freely moving animal studies.

  11. Attenuation correction for freely moving small animal brain PET studies based on a virtual scanner geometry

    International Nuclear Information System (INIS)

    Attenuation correction in positron emission tomography brain imaging of freely moving animals is a very challenging problem since the torso of the animal is often within the field of view and introduces a non negligible attenuating factor that can degrade the quantitative accuracy of the reconstructed images. In the context of unrestrained small animal imaging, estimation of the attenuation correction factors without the need for a transmission scan is highly desirable. An attractive approach that avoids the need for a transmission scan involves the generation of the hull of the animal’s head based on the reconstructed motion corrected emission images. However, this approach ignores the attenuation introduced by the animal’s torso. In this work, we propose a virtual scanner geometry which moves in synchrony with the animal’s head and discriminates between those events that traversed only the animal’s head (and therefore can be accurately compensated for attenuation) and those that might have also traversed the animal’s torso. For each recorded pose of the animal’s head a new virtual scanner geometry is defined and therefore a new system matrix must be calculated leading to a time-varying system matrix. This new approach was evaluated on phantom data acquired on the microPET Focus 220 scanner using a custom-made phantom and step-wise motion. Results showed that when the animal’s torso is within the FOV and not appropriately accounted for during attenuation correction it can lead to bias of up to 10% . Attenuation correction was more accurate when the virtual scanner was employed leading to improved quantitative estimates (bias < 2%), without the need to account for the attenuation introduced by the extraneous compartment. Although the proposed method requires increased computational resources, it can provide a reliable approach towards quantitatively accurate attenuation correction for freely moving animal studies. (paper)

  12. Jet set pets: examining the zoonosis risk in animal import and travel across the European Union

    Directory of Open Access Journals (Sweden)

    Fooks AR

    2014-12-01

    Full Text Available Anthony R Fooks,1,2 Nicholas Johnson1 1Wildlife Zoonoses and Vector-Borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, 2Department of Clinical Infection, University of Liverpool, Liverpool, UK Abstract: Ownership of companion animals or pets is popular throughout the world. Unfortunately, such animals are susceptible to and potential reservoirs of zoonotic pathogens. Close proximity to and contact with pets can lead to human infections. The distribution of zoonotic diseases associated with companion animals such as dogs and cats is not uniform around the world, and moving animals between regions, countries, and continents carries with it the risk of relocating the pathogens they might harbor. Critical among these zoonotic diseases are rabies, echinococcosis, and leishmania. In addition, the protozoan parasites, Toxoplasma gondii and Giardia duodenalis, are also significant agents for human disease of pet origin. Considerable effort is applied to controlling movements of companion animals, particularly dogs, into the European Union. However, free movement of people and their pets within the European Union is a risk factor for the translocation of diseases and their vectors. This review considers the current distribution of some of these diseases, the risks associated with pet travel, and the controls implemented within Europe to prevent the free movement of zoonotic pathogens. Keywords: zoonosis, companion animal, rabies, alveolar echinococcosis, leishmania

  13. Improved dead-time correction for PET scanners: application to small-animal PET

    International Nuclear Information System (INIS)

    Pile-up and dead-time are two main causes of nonlinearity in the response of a PET scanner as a function of activity in the field of view (FOV). For a given scanner and acquisition system, pile-up effects depend on the material and size of the object being imaged and on the distribution of activity inside and outside the FOV, because these factors change the singles-to-coincidences ratio (SCR). Thus, it is difficult to devise an accurate correction that would be valid for any acquisition. In this work, we demonstrate a linear relationship between SCR and effective dead-time, which measures the effects of both dead-time (losses) and pile-up (gains and losses). This relationship allows us to propose a simple method to accurately estimate dead-time and pile-up corrections using only two calibration acquisitions with, respectively, a high and low SCR. The method has been tested with simulations and experimental data for two different scanner geometries: a scanner with large area detectors and no pile-up rejection, and a scanner composed of two full rings of smaller detectors. Our results show that the SCR correction method is accurate within 7%, even for high activities in the FOV, and avoids the bias of the standard single-parameter method. (paper)

  14. Improved dead-time correction for PET scanners: application to small-animal PET

    Science.gov (United States)

    Vicente, E.; Herraiz, J. L.; España, S.; Herranz, E.; Desco, M.; Vaquero, J. J.; Udías, J. M.

    2013-04-01

    Pile-up and dead-time are two main causes of nonlinearity in the response of a PET scanner as a function of activity in the field of view (FOV). For a given scanner and acquisition system, pile-up effects depend on the material and size of the object being imaged and on the distribution of activity inside and outside the FOV, because these factors change the singles-to-coincidences ratio (SCR). Thus, it is difficult to devise an accurate correction that would be valid for any acquisition. In this work, we demonstrate a linear relationship between SCR and effective dead-time, which measures the effects of both dead-time (losses) and pile-up (gains and losses). This relationship allows us to propose a simple method to accurately estimate dead-time and pile-up corrections using only two calibration acquisitions with, respectively, a high and low SCR. The method has been tested with simulations and experimental data for two different scanner geometries: a scanner with large area detectors and no pile-up rejection, and a scanner composed of two full rings of smaller detectors. Our results show that the SCR correction method is accurate within 7%, even for high activities in the FOV, and avoids the bias of the standard single-parameter method.

  15. Imaging and PET-CT evaluation of Gi tract cancers

    International Nuclear Information System (INIS)

    Imaging plays a pivotal role in the management of G.I. tract cancers for diagnosis, characterization, locoregional staging, metastatic work-up and follow-up during and after curative or palliative treatment. The imaging protocols should be optimized and reproducible because of their impact on therapy. Thoracic, abdominal and pelvic CT is the cornerstone of the imaging work-up, optimized and reproducible because of their impact on therapy. Thoracic, abdominal and pelvic CT is the cornerstone of the imaging work-up, optimized and tailored to the specific G.I. segment involved, requiring good G.I. tract distension. Image interpretation of native axial and reformatted multiplanar images is routinely performed. In specific cases, additional targeted imaging with the US or MRI or whole body imaging with PET/CT or MRI may be valuable. PET/CT is a complement to morphological imaging. PET allows detection of lesions otherwise undetected on morphological imaging, usually due to poor contrast with surrounding tissues, and characterization of known lesions. PET/CT is best used as an integral part of a comprehensive imaging work-up. Radiologist and nuclear medicine specialists provide complementary information. each must be familiar with the clinical questions at hand and related stakes, and advantages and limitations of each modality to optimize treatment as part of a multidisciplinary management approach. (authors)

  16. PET Imaging of Integrin αVβ3 Expression

    Directory of Open Access Journals (Sweden)

    Ambros J. Beer, Horst Kessler, Hans-Jürgen Wester, Markus Schwaiger

    2011-01-01

    Full Text Available PET imaging of integrin αvβ3 expression has been studied intensely by the academia and recently also by the industry. Imaging of integrin αvβ3 expression is of great potential value, as the integrin αvβ3 is a key player in tumor metastasis and angiogenesis. Therefore PET imaging of this target might be a suitable in-vivo biomarker of angiogenesis and metastatic potential of tumors. In this manuscript, the various strategies for PET imaging of the integrin αvβ3 will be summarized, including monomeric and multimeric radiolabelled RGD peptides and nanoparticles. While most experiments have been performed using preclinical tumor models, more and more clinical results on PET imaging of αvβ3 expression are available and will be discussed in detail. However, while a multitude of radiotracer strategies have been successfully evaluated for PET imaging of αvβ3, the ultimate clinical value of this new imaging biomarker still has to be evaluated in large clinical trials.

  17. An evaluation of exact and approximate 3-D reconstruction algorithms for a high-resolution small-animal PET scanner

    International Nuclear Information System (INIS)

    MicroPET is a low-cost, high-resolution positron emission tomography (PET) scanner designed for imaging small animals. MicroPET operates exclusively without septa, acquiring fully three-dimensional (3-D) data sets. The performance of the projection-reprojection (3DRP), variable axial rebinning (VARB), single slice rebinning (SSRB), and Fourier rebinning (FORE) methods for reconstruction of microPET data were evaluated. The algorithms were compared with respect to resolution, noise variance, and reconstruction time. Results suggested that the 3DRP algorithm gives the best combination of resolution and noise performance in 9 min of reconstruction time on a Sun UltraSparc I workstation. The FORE algorithm provided the most acceptable accelerated method of reconstruction, giving similar resolution performance with a 10%--20% degradation in noise variance in under 2 min. Significant degradation in the axial resolution was measured with the VARB and SSRB methods, offsetting the decrease in reconstruction time achieved with those methods. In-plane angular mashing of the 3-D data before reconstruct ion led to a 50% reduction in reconstruction time but also introduced unacceptable tangential blurring artifacts. This thorough evaluation of analytical 3-D reconstruction techniques allowed for optimal selection of a reconstruction method for the diverse range of microPET applications

  18. An integrated multimodality image-guided robot system for small-animal imaging research

    International Nuclear Information System (INIS)

    We design and construct an image-guided robot system for use in small-animal imaging research. This device allows the use of co-registered small-animal PET-MRI images to guide the movements of robotic controllers, which will accurately place a needle probe at any predetermined location inside, for example, a mouse tumor, for biological readouts without sacrificing the animal. This system is composed of three major components: an automated robot device, a CCD monitoring mechanism, and a multimodality registration implementation. Specifically, the CCD monitoring mechanism was used for correction and validation of the robot device. To demonstrate the value of the proposed system, we performed a tumor hypoxia study that involved FMISO small-animal PET imaging and the delivering of a pO2 probe into the mouse tumor using the image-guided robot system. During our evaluation, the needle positioning error was found to be within 0.153±0.042 mm of desired placement; the phantom simulation errors were within 0.693±0.128 mm. In small-animal studies, the pO2 probe measurements in the corresponding hypoxia areas showed good correlation with significant, low tissue oxygen tensions (less than 6 mmHg). We have confirmed the feasibility of the system and successfully applied it to small-animal investigations. The system could be easily adapted to extend to other biomedical investigations in the future.

  19. An integrated multimodality image-guided robot system for small-animal imaging research

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Wen-Lin [Department of Radiology, Tzu-Chi University and Radiation Oncology, Buddhist Tzu-Chi General Hospital Hualien, Taiwan (China); Hsin Wu, Tung [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan (China); Hsu, Shih-Ming [Department of Biomedical Imaging and Radiological Sciences, China Medical University, Taichung, Taiwan (China); Chen, Chia-Lin [Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan (China); Lee, Jason J.S., E-mail: jslee@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan (China); Huang, Yung-Hui, E-mail: yhhuang@isu.edu.tw [Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung, Taiwan (China)

    2011-10-01

    We design and construct an image-guided robot system for use in small-animal imaging research. This device allows the use of co-registered small-animal PET-MRI images to guide the movements of robotic controllers, which will accurately place a needle probe at any predetermined location inside, for example, a mouse tumor, for biological readouts without sacrificing the animal. This system is composed of three major components: an automated robot device, a CCD monitoring mechanism, and a multimodality registration implementation. Specifically, the CCD monitoring mechanism was used for correction and validation of the robot device. To demonstrate the value of the proposed system, we performed a tumor hypoxia study that involved FMISO small-animal PET imaging and the delivering of a pO{sub 2} probe into the mouse tumor using the image-guided robot system. During our evaluation, the needle positioning error was found to be within 0.153{+-}0.042 mm of desired placement; the phantom simulation errors were within 0.693{+-}0.128 mm. In small-animal studies, the pO{sub 2} probe measurements in the corresponding hypoxia areas showed good correlation with significant, low tissue oxygen tensions (less than 6 mmHg). We have confirmed the feasibility of the system and successfully applied it to small-animal investigations. The system could be easily adapted to extend to other biomedical investigations in the future.

  20. Preclinical imaging in animal models of radiation therapy

    International Nuclear Information System (INIS)

    Modern radiotherapy benefits from precise and targeted diagnostic and pretherapeutic imaging. Standard imaging modalities, such as computed tomography (CT) offer high morphological detail but only limited functional information on tumors. Novel functional and molecular imaging modalities provide biological information about tumors in addition to detailed morphological information. Perfusion magnetic resonance imaging (MRI) CT or ultrasound-based perfusion imaging as well as hybrid modalities, such as positron emission tomography (PET) CT or MRI-PET have the potential to identify and precisely delineate viable and/or perfused tumor areas, enabling optimization of targeted radiotherapy. Functional information on tissue microcirculation and/or glucose metabolism allow a more precise definition and treatment of tumors while reducing the radiation dose and sparing the surrounding healthy tissue. In the development of new imaging methods for planning individualized radiotherapy, preclinical imaging and research plays a pivotal role, as the value of multimodality imaging can only be assessed, tested and adequately developed in a preclinical setting, i.e. in animal tumor models. New functional imaging modalities will play an increasing role for the surveillance of early treatment response during radiation therapy and in the assessment of the potential value of new combination therapies (e.g. combining anti-angiogenic drugs with radiotherapy). (orig.)

  1. Development of Input Function Measurement System for Small Animal PET Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Guk; Kim, Byung Su; Kim, Jin Su [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2010-10-15

    For quantitative measurement of radioactivity concentration in tissue and a validated tracer kinetic model, the high sensitive detection system has been required for blood sampling. With the accurate measurement of time activity curves (TACs) of labeled compounds in blood (plasma) enable to provide quantitative information on biological parameters of interest in local tissue. Especially, the development of new tracers for PET imaging requires knowledge of the kinetics of the tracer in the body and in arterial blood and plasma. Conventional approaches of obtaining an input function are to sample arterial blood sequentially by manual as a function of time. Several continuous blood sampling systems have been developed and used in nuclear medicine research field to overcome the limited temporal resolution in sampling by the conventional method. In this work, we developed the high sensitive and unique geometric design of GSO detector for small animal blood activity measurement

  2. Multi-technique hybrid imaging in PET/CT and PET/MR: what does the future hold?

    Science.gov (United States)

    de Galiza Barbosa, F; Delso, G; Ter Voert, E E G W; Huellner, M W; Herrmann, K; Veit-Haibach, P

    2016-07-01

    Integrated positron-emission tomography and computed tomography (PET/CT) is one of the most important imaging techniques to have emerged in oncological practice in the last decade. Hybrid imaging, in general, remains a rapidly growing field, not only in developing countries, but also in western industrialised healthcare systems. A great deal of technological development and research is focused on improving hybrid imaging technology further and introducing new techniques, e.g., integrated PET and magnetic resonance imaging (PET/MRI). Additionally, there are several new PET tracers on the horizon, which have the potential to broaden clinical applications in hybrid imaging for diagnosis as well as therapy. This article aims to highlight some of the major technical and clinical advances that are currently taking place in PET/CT and PET/MRI that will potentially maintain the position of hybrid techniques at the forefront of medical imaging technologies. PMID:27108800

  3. Mass effect of injected dose in small rodent imaging by SPECT and PET

    Energy Technology Data Exchange (ETDEWEB)

    Kung, M.-P. [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kung, Hank F. [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States) and Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104 (United States)]. E-mail: kunghf@sunmac.spect.upenn.edu

    2005-10-01

    This paper discusses the effect of mass (chemical quantity) of injected dose on positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Commonly, PET or SPECT imaging study uses a 'no-carrier added' dose, which contains a small amount of radioactive imaging agent (in picogram to microgram). For small animal (rodent) imaging studies, specifically targeting binding sites or biological processes, the mass (chemical quantity) in the dose may significantly modify the binding, pharmacokinetics and, ultimately, the imaging outcome. Due to differences in size and other physiological factors between humans and rodents, there is a dramatic divergence of mass effect between small animal and human imaging study. In small animal imaging studies, the mass, or effective dose (ED{sub 50}), a dose required for 50% of receptor or binding site occupancy, is usually not directly related to binding potential (B {sub max}/K {sub d}) (measured by in vitro binding assay). It is likely that dynamic interplays between specific and nonspecific binding in blood circulation, transient lung retention, kidney excretion, liver-gallbladder flow, soft tissue retention as well as metabolism could each play a significant role in determining the concentration of the tracer in the target regions. When using small animal imaging for studying drug occupancy (either by a pretreatment, coinjection or chasing dose), the mass effects on imaging outcome are important factors for consideration.

  4. Mass effect of injected dose in small rodent imaging by SPECT and PET

    International Nuclear Information System (INIS)

    This paper discusses the effect of mass (chemical quantity) of injected dose on positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Commonly, PET or SPECT imaging study uses a 'no-carrier added' dose, which contains a small amount of radioactive imaging agent (in picogram to microgram). For small animal (rodent) imaging studies, specifically targeting binding sites or biological processes, the mass (chemical quantity) in the dose may significantly modify the binding, pharmacokinetics and, ultimately, the imaging outcome. Due to differences in size and other physiological factors between humans and rodents, there is a dramatic divergence of mass effect between small animal and human imaging study. In small animal imaging studies, the mass, or effective dose (ED50), a dose required for 50% of receptor or binding site occupancy, is usually not directly related to binding potential (B max/K d) (measured by in vitro binding assay). It is likely that dynamic interplays between specific and nonspecific binding in blood circulation, transient lung retention, kidney excretion, liver-gallbladder flow, soft tissue retention as well as metabolism could each play a significant role in determining the concentration of the tracer in the target regions. When using small animal imaging for studying drug occupancy (either by a pretreatment, coinjection or chasing dose), the mass effects on imaging outcome are important factors for consideration

  5. Pet projects: animal assisted therapy in nursing homes.

    Science.gov (United States)

    Gammonley, J; Yates, J

    1991-01-01

    1. Animal assisted therapy is an applied science using animals to solve a human problem. It is an interdisciplinary approach using animals as an adjunct to other therapies. 2. The major difference between animals as therapy and entertainment is the animal-human bond, a special relationship that develops when a person has strong feelings of psychological attachment to the animal. 3. It is essential that a complete nursing and activity assessment be made before implementation of individualized animal assisted therapy. PMID:1899683

  6. FDG PET/CT imaging in canine cancer patients

    DEFF Research Database (Denmark)

    Hansen, Anders Elias; McEvoy, Fintan; Engelholm, Svend Aage;

    2011-01-01

    and organs in canine cancer patients. FDG PET/CT was performed in 14 dogs including, nine mesenchymal tumors, four carcinomas, and one incompletely excised mast cell tumor. A generally higher FDG uptake was observed in carcinomas relative to sarcomas. Maximum SUV of carcinomas ranged from 7.6 to 27.......0, and for sarcomas from 2.0 to 10.6. The FDG SUV of several organs and tissues, including regional brain uptake is reported, to serve as a reference for future FDG PET studies in canine cancer patients. Several potential pitfalls have been recognized in interpretation of FDG PET images of human patients, a number...

  7. Imaging with {sup 124}I in differentiated thyroid carcinoma: is PET/MRI superior to PET/CT?

    Energy Technology Data Exchange (ETDEWEB)

    Binse, I.; Poeppel, T.D.; Ruhlmann, M.; Gomez, B.; Bockisch, A.; Rosenbaum-Krumme, S.J. [University of Duisburg-Essen, Medical Faculty, Department of Nuclear Medicine, Essen (Germany); Umutlu, L. [University of Duisburg-Essen, Medical Faculty, Department of Radiology, Essen (Germany)

    2016-06-15

    The aim of this study was to compare integrated PET/CT and PET/MRI for their usefulness in detecting and categorizing cervical iodine-positive lesions in patients with differentiated thyroid cancer using {sup 124}I as tracer. The study group comprised 65 patients at high risk of iodine-positive metastasis who underwent PET/CT (low-dose CT scan, PET acquisition time 2 min; PET/CT{sub 2}) followed by PET/MRI of the neck 24 h after {sup 124}I administration. PET images from both modalities were analysed for the numbers of tracer-positive lesions. Two different acquisition times were used for the comparisons, one matching the PET/CT{sub 2} acquisition time (2 min, PET/MRI{sub 2}) and the other covering the whole MRI scan time (30 min, PET/MRI{sub 30}). Iodine-positive lesions were categorized as metastasis, thyroid remnant or inconclusive according to their location on the PET/CT images. Morphological information provided by MRI was considered for evaluation of lesions on PET/MRI and for volume information. PET/MRI{sub 2} detected significantly more iodine-positive metastases and thyroid remnants than PET/CT{sub 2} (72 vs. 60, p = 0.002, and 100 vs. 80, p = 0.001, respectively), but the numbers of patients with at least one tumour lesion identified were not significantly different (21/65 vs. 17/65 patients). PET/MRI{sub 30} tended to detect more PET-positive metastases than PET/MRI{sub 2} (88 vs. 72), but the difference was not significant (p = 0.07). Of 21 lesions classified as inconclusive on PET/CT, 5 were assigned to metastasis or thyroid remnant when evaluated by PET/MRI. Volume information was available in 34 % of iodine-positive metastases and 2 % of thyroid remnants on PET/MRI. PET/MRI of the neck was found to be superior to PET/CT in detecting iodine-positive lesions. This was attributed to the higher sensitivity of the PET component, Although helpful in some cases, we found no substantial advantage of PET/MRI over PET/CT in categorizing iodine

  8. Atlas of PET/MR imaging in oncology

    International Nuclear Information System (INIS)

    Numerous illustrated clinical cases in different oncology domains. Includes digital interactive software matching the cases in the book. Interactive version based on the latest web standard, HTML5, ensuring the widest compatibility. Edited by three international opinion leaders/imaging experts in the field. This new project on PET/MR imaging in oncology includes digital interactive software matching the cases in the book. The interactive version of the atlas is based on the latest web standard, HTML5, ensuring compatibility with any computer operating system as well as a dedicated version for Apple iPad and iPhone. The book opens with an introduction to the principles of hybrid imaging that pays particular attention to PET/MR imaging and standard PET/MR acquisition protocols. A wide range of illustrated clinical case reports are then presented. Each case study includes a short clinical history, findings, and teaching points, followed by illustrations, legends, and comments. The multimedia version of the book includes dynamic movies that allow the reader to browse through series of rotating 3D images (MIP or volume rendered), display blending between PET and MR, and dynamic visualization of 3D image volumes. The movies can be played either continuously or sequentially for better exploration of sets of images. The editors of this state-of-the-art publication are key opinion leaders in the field of multimodality imaging. Professor Osman Ratib (Geneva) and Professor Markus Schwaiger (Munich) were the first in Europe to initiate the clinical adoption of PET/MR imaging. Professor Thomas Beyer (Zurich) is an internationally renowned pioneering physicist in the field of hybrid imaging. Individual clinical cases presented in this book are co-authored by leading international radiologists and nuclear physicians experts in the use of PET and MRI.

  9. Atlas of PET/MR imaging in oncology

    Energy Technology Data Exchange (ETDEWEB)

    Ratib, Osman [University Hospital of Geneva (Switzerland). Nuclear Medicine Division; Schwaiger, Markus [Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik und Poliklinik; Beyer, Thomas (eds.) [General Hospital Vienna (Austria). Center for Medical Physics and Biomedical Engineering

    2013-08-01

    Numerous illustrated clinical cases in different oncology domains. Includes digital interactive software matching the cases in the book. Interactive version based on the latest web standard, HTML5, ensuring the widest compatibility. Edited by three international opinion leaders/imaging experts in the field. This new project on PET/MR imaging in oncology includes digital interactive software matching the cases in the book. The interactive version of the atlas is based on the latest web standard, HTML5, ensuring compatibility with any computer operating system as well as a dedicated version for Apple iPad and iPhone. The book opens with an introduction to the principles of hybrid imaging that pays particular attention to PET/MR imaging and standard PET/MR acquisition protocols. A wide range of illustrated clinical case reports are then presented. Each case study includes a short clinical history, findings, and teaching points, followed by illustrations, legends, and comments. The multimedia version of the book includes dynamic movies that allow the reader to browse through series of rotating 3D images (MIP or volume rendered), display blending between PET and MR, and dynamic visualization of 3D image volumes. The movies can be played either continuously or sequentially for better exploration of sets of images. The editors of this state-of-the-art publication are key opinion leaders in the field of multimodality imaging. Professor Osman Ratib (Geneva) and Professor Markus Schwaiger (Munich) were the first in Europe to initiate the clinical adoption of PET/MR imaging. Professor Thomas Beyer (Zurich) is an internationally renowned pioneering physicist in the field of hybrid imaging. Individual clinical cases presented in this book are co-authored by leading international radiologists and nuclear physicians experts in the use of PET and MRI.

  10. Fast synthesis of 11C-Raclopride and its initial PET study on animal model

    International Nuclear Information System (INIS)

    Objective: 11C-Raclopride is a type-2 dopamine receptor (D2R) binding agent used in the study of Parkinson's disease. This study introduced a fast and convenient method for preparation of 11C- Raclopride and reported on the preclinical trial of this receptor tracer on animal studies. Methods: 11C- Raclopride was synthesized via reaction of 11C-CH3-Triflate with Nor-Raclopride. The mixture of primary product was water-diluted and loaded on Sep-Pak C18 column for separation. The final product, 11C-Raclopride, was purified by column chromatography and then eluted from the C18 column with ethanol. The bio-distribution was studied in SD rats and the in vivo imaging pattern was studied in hem ipark insonjan mon- keys. Results: Within 16 min from beginning of processing with 11CO2, the synthetic yield of 11C-Raclopride was 60%, radiochemical purity (RCP) > 95% and specific activity 8 GBq/mmol. The uptake ratios of striatum to cerebellum and cerebral cortex were 4.67 and 6.20, respectively, at 30 min after 11C-Raclopride administration. The striatal uptake in normal rat brain could be blocked by N-methylspiperone (NMSP) and raclopride, but not by Nor-raclopride. PET imaging showed higher striatal D2R uptake on the D2 receptor up-regulated side of the experimental monkeys relative to the contralateral side. Conclusions: Column chromatography for purification of 11C-Raclopride was fast, convenient and with a RCP similar to that of high performance liquid chromatography purification. Preliminary PET findings using animal model suggested that 11C-Raclopride by column chromatogram purification might be considered for clinical use. (authors)

  11. Accurate and efficient modeling of the detector response in small animal multi-head PET systems

    International Nuclear Information System (INIS)

    In fully three-dimensional PET imaging, iterative image reconstruction techniques usually outperform analytical algorithms in terms of image quality provided that an appropriate system model is used. In this study we concentrate on the calculation of an accurate system model for the YAP-(S)PET II small animal scanner, with the aim to obtain fully resolution- and contrast-recovered images at low levels of image roughness. For this purpose we calculate the system model by decomposing it into a product of five matrices: (1) a detector response component obtained via Monte Carlo simulations, (2) a geometric component which describes the scanner geometry and which is calculated via a multi-ray method, (3) a detector normalization component derived from the acquisition of a planar source, (4) a photon attenuation component calculated from x-ray computed tomography data, and finally, (5) a positron range component is formally included. This system model factorization allows the optimization of each component in terms of computation time, storage requirements and accuracy. The main contribution of this work is a new, efficient way to calculate the detector response component for rotating, planar detectors, that consists of a GEANT4 based simulation of a subset of lines of flight (LOFs) for a single detector head whereas the missing LOFs are obtained by using intrinsic detector symmetries. Additionally, we introduce and analyze a probability threshold for matrix elements of the detector component to optimize the trade-off between the matrix size in terms of non-zero elements and the resulting quality of the reconstructed images. In order to evaluate our proposed system model we reconstructed various images of objects, acquired according to the NEMA NU 4-2008 standard, and we compared them to the images reconstructed with two other system models: a model that does not include any detector response component and a model that approximates analytically the depth of interaction

  12. Bayesian PET image reconstruction incorporating anato-functional joint entropy

    Science.gov (United States)

    Tang, Jing; Rahmim, Arman

    2009-12-01

    We developed a maximum a posterior (MAP) reconstruction method for positron emission tomography (PET) image reconstruction incorporating magnetic resonance (MR) image information, with the joint entropy between the PET and MR image features serving as the regularization constraint. A non-parametric method was used to estimate the joint probability density of the PET and MR images. Using realistically simulated PET and MR human brain phantoms, the quantitative performance of the proposed algorithm was investigated. Incorporation of the anatomic information via this technique, after parameter optimization, was seen to dramatically improve the noise versus bias tradeoff in every region of interest, compared to the result from using conventional MAP reconstruction. In particular, hot lesions in the FDG PET image, which had no anatomical correspondence in the MR image, also had improved contrast versus noise tradeoff. Corrections were made to figures 3, 4 and 6, and to the second paragraph of section 3.1 on 13 November 2009. The corrected electronic version is identical to the print version.

  13. Compact and mobile high resolution PET brain imager

    Science.gov (United States)

    Majewski, Stanislaw; Proffitt, James

    2011-02-08

    A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

  14. Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology

    DEFF Research Database (Denmark)

    Stauss, J.; Franzius, C.; Pfluger, T.;

    2008-01-01

    tomography ((18)F-FDG PET) in paediatric oncology. The Oncology Committee of the European Association of Nuclear Medicine (EANM) has published excellent procedure guidelines on tumour imaging with (18)F-FDG PET (Bombardieri et al., Eur J Nucl Med Mol Imaging 30:BP115-24, 2003). These guidelines, published by...... Association of Nuclear Medicine. They should be taken in the context of "good practice" of nuclear medicine and of any national rules, which may apply to nuclear medicine examinations. The recommendations of these guidelines cannot be applied to all patients in all practice settings. The guidelines should not...

  15. Imaging and Quantification of Brain Serotonergic Activity using PET

    OpenAIRE

    Lundquist, Pinelopi

    2006-01-01

    This thesis investigates the potential of using positron emission tomography (PET) to study the biosynthesis and release of serotonin (5HT) at the brain serotonergic neuron. As PET requires probe compounds with specific attributes to enable imaging and quantification of biological processes, emphasis was placed on the evaluation of these attributes. The experiments established that the 5HT transporter radioligand [11C]-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile, [11C]DASB, ...

  16. Performance of a DOI-encoding small animal PET system with monolithic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Carles, M., E-mail: montcar@ific.uv.es [Instituto de Instrumentacion para Imagen Molecular(I3M), Centro mixto CSIC-Universitat Politecnica de Valencia- IEMAT, Camino de Vera s/n, 46020 Valencia (Spain); Lerche, Ch.W. [Department X-Ray Imaging Systems, Philips Research Europe, Weisshausstrasse 2, D-52066 Aachen (Germany); Sanchez, F.; Orero, A.; Moliner, L.; Soriano, A.; Benlloch, J.M. [Instituto de Instrumentacion para Imagen Molecular(I3M), Centro mixto CSIC-Universitat Politecnica de Valencia- IEMAT, Camino de Vera s/n, 46020 Valencia (Spain)

    2012-12-11

    PET systems designed for specific applications require high resolution and sensitivity instrumentation. In dedicated system design smaller ring diameters and deeper crystals are widely used in order to increase the system sensitivity. However, this design increases the parallax error, which degrades the spatial image resolution gradually from the center to the edge of the field-of-view (FOV). Our group has designed a depth of interaction(DOI)-encoding small animal PET system based on monolithic crystals. In this work we investigate the restoration of radial resolution for transaxially off-center sources using the DOI information provided by our system. For this purpose we have designed a support for point like sources adapted to our system geometry that allows a spatial compression and resolution response study. For different point source radial positions along vertical and horizontal axes of a FOV transaxial plane we compare the results obtained by three methods: without DOI information, with the DOI provided by our system and with the assumption that all the {gamma}-rays interact at half depth of the crystal thickness. Results show an improvement of the mean resolution of 10% with the half thickness assumption and a 16% achieved using the DOI provided by the system. Furthermore, a 10% restoration of the resolution uniformity is obtained using the half depth assumption and an 18% restoration using measured DOI.

  17. A prototype of very high-resolution small animal PET scanner using silicon pad detectors

    CERN Document Server

    Park, S J; Huh, S; Kagan, H; Honscheid, K; Burdette, D; Chesi, Enrico Guido; Lacasta, C; Llosa, G; Mikuz, M; Studen, A; Weilhammer, P; Clinthorne, N H

    2007-01-01

    Abstract A very high-resolution small animal positron emission tomograph (PET), which can achieve sub-millimeter spatial resolution, is being developed using silicon pad detectors. The prototype PET for a single slice instrument consists of two 1 mm thick silicon pad detectors, each containing a 32×16 array of 1.4×1.4 mm pads readout with four VATAGP3 chips which have 128 channels low-noise self-triggering ASIC in each chip, coincidence units, a source turntable and tungsten slice collimator. The silicon detectors were located edgewise on opposite sides of a 4 cm field-of-view to maximize efficiency. Energy resolution is dominated by electronic noise, which is 0.98% (1.38 keV) FWHM at 140.5 keV. Coincidence timing resolution is 82.1 ns FWHM and coincidence efficiency was measured to be 1.04×10−3% from two silicon detectors with annihilation photons of 18F source. Image data were acquired and reconstructed using conventional 2-D filtered-back projection (FBP) and a maximum likelihood expectation maximizat...

  18. Rapid intracerebroventricular delivery of Cu-DOTA-etanercept after peripheral administration demonstrated by PET imaging

    Directory of Open Access Journals (Sweden)

    Chen Xiaoyuan

    2009-02-01

    Full Text Available Abstract Background The cytokines interleukin-1 and tumor necrosis factor (TNF, and the cytokine blocker interleukin-1 receptor antagonist, all have been demonstrated to enter the cerebrospinal fluid (CSF following peripheral administration. Recent reports of rapid clinical improvement in patients with Alzheimer's disease and related forms of dementia following perispinal administration of etanercept, a TNF antagonist, suggest that etanercept also has the ability to reach the brain CSF. To investigate, etanercept was labeled with a positron emitter to enable visualization of its intracranial distribution following peripheral administration by PET in an animal model. Findings Radiolabeling of etanercept with the PET emitter 64Cu was performed by DOTA (1,4,7,10-tetraazadodecane-N,N',N",N"'-tetraacetic acid conjugation of etanercept, followed by column purification and 64Cu labeling. MicroPET imaging revealed accumulation of 64Cu-DOTA-etanercept within the lateral and third cerebral ventricles within minutes of peripheral perispinal administration in a normal rat anesthesized with isoflurane anesthesia, with concentration within the choroid plexus and into the CSF. Conclusion Synthesis of 64Cu-DOTA-etanercept enabled visualization of its intracranial distribution by microPET imaging. MicroPET imaging documented rapid accumulation of 64Cu-DOTA-etanercept within the choroid plexus and the cerebrospinal fluid within the cerebral ventricles of a living rat after peripheral administration. Further study of the effects of etanercept and TNF at the level of the choroid plexus may yield valuable insights into the pathogenesis of Alzheimer's disease.

  19. Fusion of PET and MRI for Hybrid Imaging

    Science.gov (United States)

    Cho, Zang-Hee; Son, Young-Don; Kim, Young-Bo; Yoo, Seung-Schik

    Recently, the development of the fusion PET-MRI system has been actively studied to meet the increasing demand for integrated molecular and anatomical imaging. MRI can provide detailed anatomical information on the brain, such as the locations of gray and white matter, blood vessels, axonal tracts with high resolution, while PET can measure molecular and genetic information, such as glucose metabolism, neurotransmitter-neuroreceptor binding and affinity, protein-protein interactions, and gene trafficking among biological tissues. State-of-the-art MRI systems, such as the 7.0 T whole-body MRI, now can visualize super-fine structures including neuronal bundles in the pons, fine blood vessels (such as lenticulostriate arteries) without invasive contrast agents, in vivo hippocampal substructures, and substantia nigra with excellent image contrast. High-resolution PET, known as High-Resolution Research Tomograph (HRRT), is a brain-dedicated system capable of imaging minute changes of chemicals, such as neurotransmitters and -receptors, with high spatial resolution and sensitivity. The synergistic power of the two, i.e., ultra high-resolution anatomical information offered by a 7.0 T MRI system combined with the high-sensitivity molecular information offered by HRRT-PET, will significantly elevate the level of our current understanding of the human brain, one of the most delicate, complex, and mysterious biological organs. This chapter introduces MRI, PET, and PET-MRI fusion system, and its algorithms are discussed in detail.

  20. PET Imaging with 89Zr: From Radiochemistry to the Clinic

    OpenAIRE

    Deri, Melissa A.; Zeglis, Brian M; Francesconi, Lynn C.; Lewis, Jason S.

    2012-01-01

    The advent of antibody-based cancer therapeutics has led to the concomitant rise in the development of companion diagnostics for these therapies, particularly nuclear imaging agents. A number of radioisotopes have been employed for antibody-based PET and SPECT imaging, notably 64Cu, 124I, 111In, and 99mTc; in recent years, however, the field has increasingly focused on 89Zr, a radiometal with near ideal physical and chemical properties for immunoPET imaging. In the review at hand, we seek to ...

  1. Fabrication of animal-specific positioning molds for multi-modality imaging

    International Nuclear Information System (INIS)

    As part of efforts to image tumor-bearing animal models by PET/MRI, we tried to fabricate animal-specific positioning molds with RT CradleTM and Angel ClayTM (Donerland. Co., Korea). For successful multi-modality imaging, animal-specific positioning molds for immobilization and reproducible positioning of animal are prerequisite. First. we prepared acrylic frame fitted to microPET gantry. Pre-mixed RT CradleTM foaming reagents 'A' and 'B' were poured into the wrapped acrylic frame. During still soft, the anesthetized mouse was gently pressed into the foaming mixture for positioning. After removing the animal, entirely hardened mold was used for microPET and MR imaging. In case of Angel ClayTM, commercially available clay, the anesthetized mouse was placed on flattened clay directly, and tenderly pushed down into the mold for positioning. After the mouse was removed, the mold was completely dried at 60 .deg. C in oven overnight for next day imaging studies. The sealed pipet tip containing F-18 activity was used as fiduciary markers. U87MG tumor cells were injected subcutaneously into the right hindlimb of nude mouse. The tumor was allowed to grow up to ∼5 mm in diameter. The mouse was injected with 540 Ci of [18F]FDG. Right after microPET imaging, T2-weighted MR imaging was performed with fast gradient spin echo sequence in 0.8 mm of a slice thickness. Animal-specific beds were easily fabricated by using both RT CradleTM and Angel ClayTM. The fusion PET/MRI images were obtained by using AMIDE fusion program. U87MG tumor was clearly visualized by both microPET and MRI imaging. Animal-specific molds were successfully prepared by using cheap and easily available RT CradleTM and Angel ClayTM. Thanks to animal-specific molds, fusion images of PET and MR were obtained with little discrepancy, and small glioblastoma in mouse was easily identified in microPET images

  2. Fabrication of animal-specific positioning molds for multi-modality imaging

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Chan; Yun, Seon Young; Woo, Seung Tae; Kim, Kyeong Min; Chang, Young Min; Lee, Sang Woo; Ahn, Byeong Cheal; Lee, Jae Tae; Yoo, Jeong Soo [Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

    2007-07-01

    As part of efforts to image tumor-bearing animal models by PET/MRI, we tried to fabricate animal-specific positioning molds with RT Cradle{sup TM} and Angel Clay{sup TM} (Donerland. Co., Korea). For successful multi-modality imaging, animal-specific positioning molds for immobilization and reproducible positioning of animal are prerequisite. First. we prepared acrylic frame fitted to microPET gantry. Pre-mixed RT Cradle{sup TM} foaming reagents 'A' and 'B' were poured into the wrapped acrylic frame. During still soft, the anesthetized mouse was gently pressed into the foaming mixture for positioning. After removing the animal, entirely hardened mold was used for microPET and MR imaging. In case of Angel Clay{sup TM}, commercially available clay, the anesthetized mouse was placed on flattened clay directly, and tenderly pushed down into the mold for positioning. After the mouse was removed, the mold was completely dried at 60 .deg. C in oven overnight for next day imaging studies. The sealed pipet tip containing F-18 activity was used as fiduciary markers. U87MG tumor cells were injected subcutaneously into the right hindlimb of nude mouse. The tumor was allowed to grow up to {approx}5 mm in diameter. The mouse was injected with 540 Ci of [{sup 18}F]FDG. Right after microPET imaging, T{sub 2}-weighted MR imaging was performed with fast gradient spin echo sequence in 0.8 mm of a slice thickness. Animal-specific beds were easily fabricated by using both RT Cradle{sup TM} and Angel Clay{sup TM}. The fusion PET/MRI images were obtained by using AMIDE fusion program. U87MG tumor was clearly visualized by both microPET and MRI imaging. Animal-specific molds were successfully prepared by using cheap and easily available RT Cradle{sup TM} and Angel Clay{sup TM}. Thanks to animal-specific molds, fusion images of PET and MR were obtained with little discrepancy, and small glioblastoma in mouse was easily identified in microPET images.

  3. On the accuracy of a mutual information algorithm for PET-MR image registration

    International Nuclear Information System (INIS)

    Image registration has been increasingly used in radiation diagnosis and treatment planning as a means of information integration from different imaging modalities (e.g. MRI, PET, CT). Especially for brain lesions, accurate 3D registration and fusion of MR and PET images can provide comprehensive information about the patient under study by relating functional information from PET images to the detailed anatomical information available in MR images. However, direct PET-MR image fusion in soft tissue is complicated mainly due to the lack of conspicuous anatomical features in PET images. This study describes the implementation and validation of a mutual information registration algorithm for this purpose. Ten patients with brain lesions underwent MR and PET/CT scanning. MR-PET registration was performed a) based on the well validated MR-CT registration technique and copying the transformation to the PET images derived from the PET/CT scan (MR/PET/CT registration method) and b) directly from the MR and PET images without taking into account the CT images (MR/PET registration method). In order to check the registration accuracy of the MR/PET method, the lesion (target) was contoured in the PET images and it was transferred to the MR images using both the above methods. The MR/PET/CT method served as the gold standard for target contouring. Target contours derived by the MR/PET method were compared with the gold standard target contours for each patient and the deviation between the two contours was used to estimate the accuracy of the PET-MR registration method. This deviation was less than 3 mm (i.e. comparable to the imaging voxel of the PET/CT scanning) for 9/10 of the cases studied. Results show that the mutual information algorithm used is able to perform the PET-MR registration reliably and accurately.

  4. In vivo PET imaging of implanted cells in a Parkinson's disease rat model

    International Nuclear Information System (INIS)

    Objective: It is a major hurdle for the researchers to mornitor the implanted cells differentiation in vivo. This study was designed as a proof of concept of the feasibility to track the efficacy of transplanted human retinal pigment epithelial (RPE) cells in a Parkinson's disease (PD) rat model using PET. Methods: RPE cells or normal saline were injected into striatum of the injured side of the models in treated group(12 rats) and control group(11 rats), respectively. PET imaging on both groups was under- taken before and at certain intervals after the transplantation using 11C-raclopride and 11C-CFT as the markers. Behavioral observation and immunofluorescence confocal microscopy also conducted to prove PET results. Results: PET studies showed increased 11C-raclopride accumulation and decreased 11C-CFT in the injured side of striatum in both groups before transplantation. The 11C-raclopride striatum/cerebellum ratio at ipsilateral side decreased from 1.870 ± 0.465 to 1.601 ± 0.257 after transplantation, along with a concomitant increase of 11C-CFT accumulation in the same area (1.827 ± 0.347 to 2.336 ± 0.326) in treated group. The changes of PET studies paralleled the behavior states and confocal microscopic observations in the treated animals. Conclusion: Even a clinical PET scanner could provide to certain extent some information on the existence and in vivo differentiation of RPE cells in a PD rat model. (authors)

  5. Noninvasive Assessment of Hypoxia in Rabbit Advanced Atherosclerosis Using 18F-fluoromisonidazole PET Imaging

    Science.gov (United States)

    Mateo, Jesus; Izquierdo-Garcia, David; Badimon, Juan J.; Fayad, Zahi A.; Fuster, Valentin

    2014-01-01

    Background Hypoxia is an important microenvironmental factor influencing atherosclerosis progression by inducing foam-cell formation, metabolic adaptation of infiltrated macrophages and plaque neovascularization. Therefore, imaging plaque hypoxia could serve as a marker of lesions at risk. Methods and Results Advanced aortic atherosclerosis was induced in 18 rabbits by atherogenic diet and double balloon endothelial denudation. Animals underwent 18F-FMISO PET and 18F-fluorodeoxyglucose (18F-FDG) PET imaging after 6–8 months (atherosclerosis induction) and 12–16 months (progression) of diet initiation. Four rabbits fed standard chow served as controls. Radiotracer uptake of the abdominal aorta was measured using standardized uptake values (SUV). Following imaging, plaque hypoxia (pimonidazole), macrophages (RAM-11), neovessels (CD31) and hypoxia-inducible factor-1α (HIF-1α) were assessed by immunohistochemistry. 18F-FMISO uptake increased with time on diet (SUVmean, 0.10±0.01 in non-atherosclerotic animals versus 0.20±0.03 (P=0.002) at induction and 0.25±0.03 (P<0.001) at progression). Ex vivo PET imaging corroborated the 18F-FMISO uptake by the aorta of atherosclerotic rabbits. 18F-FDG uptake also augmented in atherosclerotic animals, with a SUVmean of 0.43±0.02 at induction versus 0.35±0.02 in non-atherosclerotic animals (P=0.031), and no further increase at progression. By immunohistochemistry, hypoxia was mainly located in the macrophage-rich areas within the atheromatous core, whereas the macrophages close to the lumen were hypoxia-negative. Intraplaque neovessels were found predominantly in macrophage-rich hypoxic regions (pimonidazole+/HIF-1α+/RAM-11+). Conclusions Plaque hypoxia increases with disease progression and is present in macrophage-rich areas associated with neovascularization. 18F-FMISO PET imaging emerges as a new tool for detection of atherosclerotic lesions. PMID:24508668

  6. In vivo PET imaging of beta-amyloid deposition in mouse models of Alzheimer's disease with a high specific activity PET imaging agent [18F]flutemetamol

    OpenAIRE

    Snellman, Anniina; Rokka, Johanna; Lopez-Picon, Francisco R; Eskola, Olli; Salmona, Mario; Forloni, Gianluigi; Scheinin, Mika; Solin, Olof; Rinne, Juha O; Haaparanta-Solin, Merja

    2014-01-01

    Background: The purpose of the study was to evaluate the applicability of 18F-labelled amyloid imaging positron emission tomography (PET) agent [18F]flutemetamol to detect changes in brain beta-amyloid (Aβ) deposition in vivo in APP23, Tg2576 and APPswe-PS1dE9 mouse models of Alzheimer's disease. We expected that the high specific activity of [18F]flutemetamol would make it an attractive small animalimaging agent. Methods: [18F]flutemetamol uptake in the m...

  7. 11C-Acetate PET imaging for renal cell carcinoma

    International Nuclear Information System (INIS)

    In this study, we investigated the effectiveness of positron emission tomography (PET) with 11C-acetate (AC) for evaluation of renal cell carcinoma. Enrolled in the study were 20 patients with suspected renal tumour, one of whom had three renal lesions. In all, 22 renal lesions were evaluated. Following administration of 350 MBq (10 mCi) of AC, whole-body PET images were obtained. Based on these PET findings, kidney lesions were scored as positive or negative. The PET results were correlated with the CT findings and histological diagnosis after surgery. In 18 patients, 20 tumours were diagnosed as renal cell carcinoma. Lesions in the remaining two patients were diagnosed as complicated cyst without malignant tissue. Of the 20 renal cell carcinomas. 14 (70%) showed positive AC PET findings; 6 were negative. The two patients with complicated cyst had negative AC PET findings. Of the 20 renal cell carcinomas, 19 were clear-cell carcinoma and 1 was a papillary cell carcinoma. This papillary cell carcinoma showed high AC uptake. AC demonstrates marked uptake in renal cell carcinoma. These preliminary data show that AC is a possible PET tracer for detection of renal cancer. (orig.)

  8. PET/CT imaging in lung cancer: indications and findings

    Directory of Open Access Journals (Sweden)

    Bruno Hochhegger

    2015-06-01

    Full Text Available The use of PET/CT imaging in the work-up and management of patients with lung cancer has greatly increased in recent decades. The ability to combine functional and anatomical information has equipped PET/CT to look into various aspects of lung cancer, allowing more precise disease staging and providing useful data during the characterization of indeterminate pulmonary nodules. In addition, the accuracy of PET/CT has been shown to be greater than is that of conventional modalities in some scenarios, making PET/CT a valuable noninvasive method for the investigation of lung cancer. However, the interpretation of PET/CT findings presents numerous pitfalls and potential confounders. Therefore, it is imperative for pulmonologists and radiologists to familiarize themselves with the most relevant indications for and limitations of PET/CT, seeking to protect their patients from unnecessary radiation exposure and inappropriate treatment. This review article aimed to summarize the basic principles, indications, cancer staging considerations, and future applications related to the use of PET/CT in lung cancer.

  9. Transforming a Targeted Porphyrin Theranostic Agent into a PET Imaging Probe for Cancer

    Directory of Open Access Journals (Sweden)

    Jiyun Shi, Tracy W.B. Liu, Juan Chen, David Green, David Jaffray, Brian C. Wilson, Fan Wang, Gang Zheng

    2011-01-01

    Full Text Available Porphyrin based photosensitizers are useful agents for photodynamic therapy (PDT and fluorescence imaging of cancer. Porphyrins are also excellent metal chelators forming highly stable metallo-complexes making them efficient delivery vehicles for radioisotopes. Here we investigated the possibility of incorporating 64Cu into a porphyrin-peptide-folate (PPF probe developed previously as folate receptor (FR targeted fluorescent/PDT agent, and evaluated the potential of turning the resulting 64Cu-PPF into a positron emission tomography (PET probe for cancer imaging. Noninvasive PET imaging followed by radioassay evaluated the tumor accumulation, pharmacokinetics and biodistribution of 64Cu-PPF. 64Cu-PPF uptake in FR-positive tumors was visible on small-animal PET images with high tumor-to-muscle ratio (8.88 ± 3.60 observed after 24 h. Competitive blocking studies confirmed the FR-mediated tracer uptake by the tumor. The ease of efficient 64Cu-radiolabeling of PPF while retaining its favorable biodistribution, pharmacokinetics and selective tumor uptake, provides a robust strategy to transform tumor-targeted porphyrin-based photosensitizers into PET imaging probes.

  10. Development of a simultaneous optical/PET imaging system for awake mice

    Science.gov (United States)

    Takuwa, Hiroyuki; Ikoma, Yoko; Yoshida, Eiji; Tashima, Hideaki; Wakizaka, Hidekatsu; Shinaji, Tetsuya; Yamaya, Taiga

    2016-09-01

    Simultaneous measurements of multiple physiological parameters are essential for the study of brain disease mechanisms and the development of suitable therapies to treat them. In this study, we developed a measurement system for simultaneous optical imaging and PET for awake mice. The key elements of this system are the OpenPET, optical imaging and fixation apparatus for an awake mouse. The OpenPET is our original open-type PET geometry, which can be used in combination with another device because of the easily accessible open space of the former. A small prototype of the axial shift single-ring OpenPET was used. The objective lens for optical imaging with a mounted charge-coupled device camera was placed inside the open space of the AS-SROP. Our original fixation apparatus to hold an awake mouse was also applied. As a first application of this system, simultaneous measurements of cerebral blood flow (CBF) by laser speckle imaging (LSI) and [11C]raclopride-PET were performed under control and 5% CO2 inhalation (hypercapnia) conditions. Our system successfully obtained the CBF and [11C]raclopride radioactivity concentration simultaneously. Accumulation of [11C]raclopride was observed in the striatum where the density of dopamine D2 receptors is high. LSI measurements could be stably performed for more than 60 minutes. Increased CBF induced by hypercapnia was observed while CBF under the control condition was stable. We concluded that our imaging system should be useful for investigating the mechanisms of brain diseases in awake animal models.

  11. Small animal imaging. Basics and practical guide

    International Nuclear Information System (INIS)

    Small animal imaging has been recognized as an important tool in preclinical research. Nevertheless, the results of non-invasive imaging are often disappointing owing to choice of a suboptimal imaging modality and/or shortcomings in study design, experimental setup, and data evaluation. This textbook is a practical guide to the use of non-invasive imaging in preclinical research. Each of the available imaging modalities is discussed in detail, with the assistance of numerous informative illustrations. In addition, many useful hints are provided on the installation of a small animal unit, study planning, animal handling, and the cost-effective performance of small animal imaging. Cross-calibration methods, data postprocessing, and special imaging applications are also considered in depth. This is the first book to cover all the practical basics in small animal imaging, and it will prove an invaluable aid for researchers, students, and technicians. (orig.)

  12. Small Animal Radionuclide Imaging With Focusing Gamma-Ray Optics

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R; Decker, T; Epstein, M; Ziock, K; Pivovaroff, M J; Craig, W W; Jernigan, J G; Barber, W B; Christensen, F E; Funk, T; Hailey, C J; Hasegawa, B H; Taylor, C

    2004-02-27

    Significant effort currently is being devoted to the development of noninvasive imaging systems that allow in vivo assessment of biological and biomolecular interactions in mice and other small animals. While physiological function in small animals can be localized and imaged using conventional radionuclide imaging techniques such as single-photon emission tomography (SPECT) and positron emission tomography (PET), these techniques inherently are limited to spatial resolutions of 1-2 mm. For this reason, we are developing a small animal radionuclide imaging system (SARIS) using grazing incidence optics to focus gamma-rays emitted by {sup 125}I and other radiopharmaceuticals. We have developed a prototype optic with sufficient accuracy and precision to focus the 27.5 keV photons from {sup 125}I onto a high-resolution imaging detector. Experimental measurements from the prototype have demonstrated that the optic can focus X-rays from a microfocus X-ray tube to a spot having physical dimensions (approximately 1500 microns half-power diameter) consistent with those predicted by theory. Our theoretical and numerical analysis also indicate that an optic can be designed and build that ultimately can achieve 100 {micro}m spatial resolution with sufficient efficiency to perform in vivo single photon emission imaging studies in small animal.

  13. PET/SPECT imaging: From carotid vulnerability to brain viability

    Energy Technology Data Exchange (ETDEWEB)

    Meerwaldt, Robbert [Department of Surgery, Isala Clinics, Zwolle (Netherlands); Slart, Riemer H.J.A. [Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands); Dam, Gooitzen M. van [Department of Surgery, University Medical Center Groningen, Groningen (Netherlands); Luijckx, Gert-Jan [Department of Neurology, University Medical Center Groningen, Groningen (Netherlands); Tio, Rene A. [Department of Cardiology, University Medical Center Groningen, Groningen (Netherlands); Zeebregts, Clark J. [Department of Surgery, University Medical Center Groningen, Groningen (Netherlands)], E-mail: czeebregts@hotmail.com

    2010-04-15

    Background: Current key issues in ischemic stroke are related to carotid plaque vulnerability, brain viability, and timing of intervention. The treatment of ischemic stroke has evolved into urgent active interventions, as 'time is brain'. Functional imaging such as positron emission tomography (PET)/single photon emission computed tomography (SPECT) could improve selection of patients with a vulnerable plaque and evaluation of brain viability in ischemic stroke. Objective: To describe the current applications of PET and SPECT as a diagnostic tool in relation to ischemic stroke. Methods: A literature search using PubMed identified articles. Manual cross-referencing was also performed. Results: Several papers, all observational studies, identified PET/SPECT to be used as a tool to monitor systemic atheroma modifying treatment and to select high-risk patients for surgery regardless of the degree of luminal stenosis in carotid lesions. Furthermore, PET/SPECT is able to quantify the penumbra region during ischemic stroke and in this way may identify those patients who may benefit from timely intervention. Discussion: Functional imaging modalities such as PET/SPECT may become important tools for risk-assessment and evaluation of treatment strategies in carotid plaque vulnerability and brain viability. Prospective clinical studies are needed to evaluate the diagnostic accuracy of PET/SPECT.

  14. PET/SPECT imaging: From carotid vulnerability to brain viability

    International Nuclear Information System (INIS)

    Background: Current key issues in ischemic stroke are related to carotid plaque vulnerability, brain viability, and timing of intervention. The treatment of ischemic stroke has evolved into urgent active interventions, as 'time is brain'. Functional imaging such as positron emission tomography (PET)/single photon emission computed tomography (SPECT) could improve selection of patients with a vulnerable plaque and evaluation of brain viability in ischemic stroke. Objective: To describe the current applications of PET and SPECT as a diagnostic tool in relation to ischemic stroke. Methods: A literature search using PubMed identified articles. Manual cross-referencing was also performed. Results: Several papers, all observational studies, identified PET/SPECT to be used as a tool to monitor systemic atheroma modifying treatment and to select high-risk patients for surgery regardless of the degree of luminal stenosis in carotid lesions. Furthermore, PET/SPECT is able to quantify the penumbra region during ischemic stroke and in this way may identify those patients who may benefit from timely intervention. Discussion: Functional imaging modalities such as PET/SPECT may become important tools for risk-assessment and evaluation of treatment strategies in carotid plaque vulnerability and brain viability. Prospective clinical studies are needed to evaluate the diagnostic accuracy of PET/SPECT.

  15. A phantom study of tumor contouring on PET imaging

    International Nuclear Information System (INIS)

    Objective: To explore an algorithm to define the threshold value for tumor contouring on 18F-fluorodeoxyglucose (FDG) PET imaging. Methods: A National Electrical Manufacturing Association (NEMA)NU 2 1994 PET phantom with 5 spheres of different diameters were filled with 18F-FDG. Seven different sphere-to-background ratios were obtained and the phantom was scanned by Discovery LS 4. For each sphere-to-background ratio, the maximum standardized uptake value (SUVmax) of each sphere, the SUV of the border of each sphere (SUVborder), the mean SUV of a 1 cm region of background (SUVbg) and the diameter (D) of each sphere were measured. SPSS 13.0 software was used for curve fitting and regression analysis to obtain the threshold algorithm. The calculated thresholds were applied to delineate 29 pathologically confirmed lung cancer lesions on PET images and the obtained volumes were compared with the volumes contoured on CT images in lung window. Results: The algorithm for defining contour threshold is TH% = 33.1% + 46.8% SUVbg/SUVmax + 13.9%/D (r = 0.994) by phantom studies. For 29 lung cancer lesions, the average gross tumor volumes (GTV) delineated on PET and CT are (7.36±1.62) ml and (8.31±2.05) ml, respectively (t = -1.26, P>0.05). Conclusion: The proposed threshold algorithm for tumor contouring on PET image could provide comparable GTV with CT. (authors)

  16. Monitoring proton radiation therapy with in-room PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Xuping; Ouyang Jinsong; El Fakhri, Georges [Department of Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States); Espana, Samuel; Daartz, Juliane; Liebsch, Norbert; Paganetti, Harald; Bortfeld, Thomas R, E-mail: elfakhri@pet.mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114 (United States)

    2011-07-07

    We used a mobile positron emission tomography (PET) scanner positioned within the proton therapy treatment room to study the feasibility of proton range verification with an in-room, stand-alone PET system, and compared with off-line equivalent studies. Two subjects with adenoid cystic carcinoma were enrolled into a pilot study in which in-room PET scans were acquired in list-mode after a routine fractionated treatment session. The list-mode PET data were reconstructed with different time schemes to generate in-room short, in-room long and off-line equivalent (by skipping coincidences from the first 15 min during the list-mode reconstruction) PET images for comparison in activity distribution patterns. A phantom study was followed to evaluate the accuracy of range verification for different reconstruction time schemes quantitatively. The in-room PET has a higher sensitivity compared to the off-line modality so that the PET acquisition time can be greatly reduced from 30 to <5 min. Features in deep-site, soft-tissue regions were better retained with in-room short PET acquisitions because of the collection of {sup 15}O component and lower biological washout. For soft tissue-equivalent material, the distal fall-off edge of an in-room short acquisition is deeper compared to an off-line equivalent scan, indicating a better coverage of the high-dose end of the beam. In-room PET is a promising low cost, high sensitivity modality for the in vivo verification of proton therapy. Better accuracy in Monte Carlo predictions, especially for biological decay modeling, is necessary.

  17. PET imaging in ectopic Cushing syndrome: a systematic review.

    Science.gov (United States)

    Santhanam, Prasanna; Taieb, David; Giovanella, Luca; Treglia, Giorgio

    2015-11-01

    Cushing syndrome due to endogenous hypercortisolism may cause significant morbidity and mortality. The source of excess cortisol may be adrenal, pituitary, or ectopic. Ectopic Cushing syndrome is sometimes difficult to localize on conventional imaging like CT and MRI. After performing a multilevel thoracoabdominal imaging with CT, the evidence regarding the use of radiotracers for PET imaging is unclear due to significant molecular and etiological heterogeneity of potential causes of ectopic Cushing's syndrome. In our systematic review of literature, it appears that GalLium-based (Ga68) somatostatin receptor analogs have better sensitivity in diagnosis of bronchial carcinoids causing Cushing syndrome and FDG PET appears superior for small-cell lung cancers and other aggressive tumors. Further large-scale studies are needed to identify the best PET tracer for this condition. PMID:26206753

  18. A detector head design for small-animal PET with silicon photomultipliers (SiPM).

    Science.gov (United States)

    Moehrs, Sascha; Del Guerra, Alberto; Herbert, Deborah J; Mandelkern, Mark A

    2006-03-01

    Small-animal PET systems are now striving for sub-millimetre resolution. Current systems based upon PSPMTs and finely pixellated scintillators can be pushed to higher resolution, but at the expense of other performance parameters and a rapidly escalating cost. Moreover, depth of interaction (DOI) information is usually difficult to assess in such systems, even though this information is highly desirable to reduce the parallax error, which is often the dominant error for such high-resolution systems. In this study we propose a high-resolution detector head for a small-animal PET imaging system with intrinsic DOI information. Instead of a pixellated scintillator, our design is based upon the classic Anger camera principle, i.e. the head is constructed of modular layers each consisting of a continuous slab of scintillator, viewed by a new type of compact silicon photodetector. The photodetector is the recently developed silicon photomultiplier (SiPM) that as well as being very compact has many other attractive properties: high gain at low bias voltage, excellent single-photoelectron resolution and fast timing. A detector head of about 4 x 4 cm2 in area is proposed, constructed from three modular layers of the type described above. We perform a simulation study, using the Monte Carlo simulation package Geant4. The simulation results are used to optimize the geometry of the detector head and characterize its performance. Additionally, hit estimation algorithms are studied to determine the interaction position of annihilation photons correctly over the whole detector surface. The resulting detector has a nearly uniform efficiency for 511 keV photons of approximately 70% and an intrinsic spatial resolution of less than approximately 0.4 mm full width at half maximum (fwhm). PMID:16481681

  19. Infection imaging using whole-body FDG-PET

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for the detection of soft tissue and bone infections. Forty-five PET examinations in 39 patients (26 male, 13 female, age range 27-86 years) with suspected infectious foci were examined with whole- or partial-body PET scans using FDG. Twenty-seven scans were done in patients with soft tissue and 18 in patients with bone infections. Corrected and uncorrected transaxial PET images were acquired. Seven hundred and twelve body regions in these 45 PET scans were evaluated. Pathological findings were graded using a confidence scale from A to E (A, definitive infection; E, no infection). Disease status was defined in all patients by culture, biopsy or surgery and clinical follow-up. In 45 PET scans there were 40 true-positive, four false-positive and one false-negative findings. Twelve foci suspected to be infectious in nature on the basis of other imaging examinations were identified as negative by PET, thus representing true-negative findings. Sensitivities for the patients with soft tissue (STI) and bone infections (BI) and for the pooled data were 96%, 100% and 98%, respectively. As the calculation of specificity is not straightforward, it was calculated on a per lesion as well as on a per body region basis to permit estimation of an upper and a lower limit. On a per lesion basis, specificities were 70% (STI), 83% (BI) and 75% for the pooled data and on a per body region basis (dividing the body into 22 regions) they were 99% (STI), 99% (BI) and 99% for the pooled data. One false-negative result was found in a patient with cholangitis. It is concluded that PET appears to be a highly sensitive method to detect infectious foci. Specificity is more difficult to estimate, but is probably in the range from 70% to above 90%. (orig.)

  20. Importance of PET/CT for imaging of colorectal cancer; Stellenwert der PET/CT zur Bildgebung des kolorektalen Karzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Meinel, F.G.; Schramm, N.; Graser, A.; Reiser, M.F.; Rist, C. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Haug, A.R. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Klinik und Poliklinik fuer Nuklearmedizin, Muenchen (Germany)

    2012-06-15

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has emerged as a very useful imaging modality in the management of colorectal carcinoma. Data from the literature regarding the role of PET/CT in the initial diagnosis, staging, radiotherapy planning, response monitoring and surveillance of colorectal carcinoma is presented. Future directions and economic aspects are discussed. Computed tomography (CT), magnetic resonance imaging (MRI) and FDG-PET for colorectal cancer and endorectal ultrasound for rectal cancer. Combined FDG-PET/CT. While other imaging modalities allow superior visualization of the extent and invasion depth of the primary tumor, PET/CT is most sensitive for the detection of distant metastases of colorectal cancer. We recommend a targeted use of PET/CT in cases of unclear M staging, prior to metastasectomy and in suspected cases of residual or recurrent colorectal carcinoma with equivocal conventional imaging. The role of PET/CT in radiotherapy planning and response monitoring needs to be determined. Currently there is no evidence to support the routine use of PET/CT for colorectal screening, staging or surveillance. To optimally exploit the synergy between morphologic and functional information, FDG-PET should generally be performed as an integrated FDG-PET/CT with a contrast-enhanced CT component in colorectal carcinoma. (orig.) [German] Die Fluordesoxyglukose-Positronenemissionstomographie/Computertomographie (FDG-PET/CT) hat in den letzten Jahren zunehmende Bedeutung zur Bildgebung des kolorektalen Karzinoms erlangt. In diesem Beitrag stellen wir den Stand der Literatur zur Rolle der PET/CT bei Screening, Staging, Bestrahlungsplanung, Beurteilung eines Therapieansprechens und Nachsorge des kolorektalen Karzinoms dar. Zudem wird auf gesundheitsoekonomische Aspekte und zukuenftige Entwicklungen eingegangen. CT, MRT, FDG-PET, beim Rektumkarzinom zusaetzlich endorektaler Ultraschall. Kombinierte FDG-PET/CT. Waehrend

  1. Influence of Iterative Reconstruction Algorithms on PET Image Resolution

    Science.gov (United States)

    Karpetas, G. E.; Michail, C. M.; Fountos, G. P.; Valais, I. G.; Nikolopoulos, D.; Kandarakis, I. S.; Panayiotakis, G. S.

    2015-09-01

    The aim of the present study was to assess image quality of PET scanners through a thin layer chromatography (TLC) plane source. The source was simulated using a previously validated Monte Carlo model. The model was developed by using the GATE MC package and reconstructed images obtained with the STIR software for tomographic image reconstruction. The simulated PET scanner was the GE DiscoveryST. A plane source consisted of a TLC plate, was simulated by a layer of silica gel on aluminum (Al) foil substrates, immersed in 18F-FDG bath solution (1MBq). Image quality was assessed in terms of the modulation transfer function (MTF). MTF curves were estimated from transverse reconstructed images of the plane source. Images were reconstructed by the maximum likelihood estimation (MLE)-OSMAPOSL, the ordered subsets separable paraboloidal surrogate (OSSPS), the median root prior (MRP) and OSMAPOSL with quadratic prior, algorithms. OSMAPOSL reconstruction was assessed by using fixed subsets and various iterations, as well as by using various beta (hyper) parameter values. MTF values were found to increase with increasing iterations. MTF also improves by using lower beta values. The simulated PET evaluation method, based on the TLC plane source, can be useful in the resolution assessment of PET scanners.

  2. MRI and PET images fusion based on human retina model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The diagnostic potential of brain positron emission tomography (PET) imaging is limited by low spatial resolution.For solving this problem we propose a technique for the fusion of PET and MRI images. This fusion is a trade-off between the spectral information extracted from PET images and the spatial information extracted from high spatial resolution MRI. The proposed method can control this trade-off. To achieve this goal, it is necessary to build a multiscale fusion model, based on the retinal cell photoreceptors model. This paper introduces general prospects of this model, and its application in multispectral medical image fusion. Results showed that the proposed method preserves more spectral features with less spatial distortion.transform methods, the best spectral and spatial quality is only achieved simultaneously with the proposed feature-based data fusion method. This method does not require resampling images, which is an advantage over the other methods, and can perform in any aspect ratio between the pixels of MRI and PET images.

  3. Quantitative carotid PET/MR imaging: clinical evaluation of MR-Attenuation correction versus CT-Attenuation correction in 18F-FDG PET/MR emission data and comparison to PET/CT

    OpenAIRE

    Bini, Jason; Robson, Philip M.; Calcagno, Claudia; Eldib, Mootaz; Fayad, Zahi A.

    2015-01-01

    Current PET/MR systems employ segmentation of MR images and subsequent assignment of empirical attenuation coefficients for quantitative PET reconstruction. In this study we examine the differences in the quantification of 18F-FDG uptake in the carotid arteries between PET/MR and PET/CT scanners. Five comparisons were performed to asses differences in PET quantification: i) PET/MR MR-based AC (MRAC) versus PET/MR CTAC, ii) PET/MR MRAC versus PET/CT, iii) PET/MR MRAC with carotid coil versus P...

  4. Gallium-68 EDTA PET/CT for Renal Imaging.

    Science.gov (United States)

    Hofman, Michael S; Hicks, Rodney J

    2016-09-01

    Nuclear medicine renal imaging provides important functional data to assist in the diagnosis and management of patients with a variety of renal disorders. Physiologically stable metal chelates like ethylenediaminetetraacetic acid (EDTA) and diethylenetriamine penta-acetate (DTPA) are excreted by glomerular filtration and have been radiolabelled with a variety of isotopes for imaging glomerular filtration and quantitative assessment of glomerular filtration rate. Gallium-68 ((68)Ga) EDTA PET usage predates Technetium-99m ((99m)Tc) renal imaging, but virtually disappeared with the widespread adoption of gamma camera technology that was not optimal for imaging positron decay. There is now a reemergence of interest in (68)Ga owing to the greater availability of PET technology and use of (68)Ga to label other radiotracers. (68)Ga EDTA can be used a substitute for (99m)Tc DTPA for wide variety of clinical indications. A key advantage of PET for renal imaging over conventional scintigraphy is 3-dimensional dynamic imaging, which is particularly helpful in patients with complex anatomy in whom planar imaging may be nondiagnostic or difficult to interpret owing to overlying structures containing radioactive urine that cannot be differentiated. Other advantages include accurate and absolute (rather than relative) camera-based quantification, superior spatial and temporal resolution and integrated multislice CT providing anatomical correlation. Furthermore, the (68)Ga generator enables on-demand production at low cost, with no additional patient radiation exposure compared with conventional scintigraphy. Over the past decade, we have employed (68)Ga EDTA PET/CT primarily to answer difficult clinical questions in patients in whom other modalities have failed, particularly when it was envisaged that dynamic 3D imaging would be of assistance. We have also used it as a substitute for (99m)Tc DTPA if unavailable owing to supply issues, and have additionally examined the role of

  5. Feasibility of breathing-adapted PET/CT imaging for radiation therapy of Hodgkin lymphoma

    DEFF Research Database (Denmark)

    Aznar, M C; Andersen, Flemming; Berthelsen, A K;

    2011-01-01

    Aim: Respiration can induce artifacts in positron emission tomography (PET)/computed tomography (CT) images leading to uncertainties in tumour volume, location and uptake quantification. Respiratory gating for PET images is now established but is not directly translatable to a radiotherapy setup....... uptake in PET/CT images. These results suggest that advanced therapies (such as SUV-based dose painting) will likely require breathing-adapted PET images and that the relevant SUV thresholds are yet to be investigated....

  6. 124I labeled Arg-Gly-Asp (RGD) peptide: PET/MR fusion imaging of tumor expressing integrin v3

    International Nuclear Information System (INIS)

    Tumor-induced angiogenesis and metastasis express high level of integrin v3 which has become a promising diagnostic biomarker and therapeutic target for various tumors. Radiolabeled RGD (Arg-Gly-Asp) peptides are well known to specifically bind to integrin and can be used not only for noninvasive imaging of integrin over-expression but also for integrin-targeted radionuclide therapy. We used three RGDyK derivatives, monomeric-, dimeric- and tetrameric-RGD for radio labeling. They were labeled with [124I]NaI using iodo-bead. Labeled RGD peptide was purified by FPLC. Xenografts were induced by subcutaneous injection of 1X107 U87MG cells into the right thigh of female Balb/c nude mice. After injection of 124I-labeled monomeric-RGD via the tail vein, the microPET imaging was obtained during 2 hours. Right after microPET imaging, T2-weighted MR imaging was performed with fast gradient spin echo sequence in 0.8 mm of a slice thickness. PET/MR fusion images were constructed by AMIDE program. For immobilization and reproducible positioning of animal, animal-specific positioning molds were fabricated. Monomeric-RGD peptide was labeled with 124I in labeling yield of 50%. After FPLC purification, the radiochemical purity was above 90%. U87MG tumor was clearly seen in both microPET and MR imaging of tumor-bearing nude mouse. The fusion imaging was well constructed by using AMIDE with little discrepancy thanks to animal-specific molds. Three RGD derivatives were also labeled with 131I in labeling yield of 20-55%. All three RGD peptides were successfully radioiodinated with 124I or 131I. U87MG glioblastoma tumor was clearly visualized in PET/MR fusion imaging. MicroPET/MR fusion imaging of dimeric- and tetrameric-RGD peptides in tumor bearing mice will also be presented during conference

  7. Use of segmented CT transmission map to avoid metal artifacts in PET images by a PET-CT device

    International Nuclear Information System (INIS)

    Background: Attenuation correction is generally used to PET images to achieve count rate values independent from tissue densities. The goal of this study was to provide a qualitative comparison of attenuation corrected PET images produced by a PET-CT device (CT, 120 kV, 40 mAs, FOV 600 mm) with and without segmentation of transmission data (ACseg+ and ACseg-respectively). Methods: The reconstructed images were compared to attenuation corrected images obtained with a high-energy transmission source (Cs-137 – 662 keV). Thirty oncologic patients were studied using CT and 137Cs for attenuation correction. All image data were acquired using the Gemini PET-CT scanner (Philips Medical Systems). It is an open PET-CT system that consists of the MX8000 multislice CT and the Allegro PET scanner arranged in a separable configuration. Images with ACseg+ and ACseg- were analyzed simultaneously in coronal, sagittal and transaxial planes. Two nuclear medicine physicians reviewed the image sets. Results: The image quality in the area of metal implants was better with ACseg+ than ACseg-, without metal induced artifacts generally observed in CT corrected images. Further the images with ACseg+ were qualitatively comparable to those obtained with 137Cs attenuation correction. Conclusions: In case of metal implants, PET studies corrected by CT should preferably use the ACseg+ method to avoid the image artifacts

  8. Enclosure for small animals during awake animal imaging

    Science.gov (United States)

    Goddard, Jr., James S

    2013-11-26

    An enclosure or burrow restrains an awake animal during an imaging procedure. A tubular body, made from a radiolucent material that does not attenuate x-rays or gamma rays, accepts an awake animal. A proximal end of the body includes an attachment surface that corresponds to an attachment surface of an optically transparent and optically uniform window. An anti-reflective coating may be applied to an inner surface, an outer surface, or both surfaces of the window. Since the window is a separate element of the enclosure and it is not integrally formed as part of the body, it can be made with optically uniform thickness properties for improved motion tracking of markers on the animal with a camera during the imaging procedure. The motion tracking information is then used to compensate for animal movement in the image.

  9. Image Registration for PET/CT and CT Images with Particle Swarm Optimization

    International Nuclear Information System (INIS)

    Image registration is a fundamental task in image processing used to match two or more images. It gives new information to the radiologists by matching images from different modalities. The objective of this study is to develop 2D image registration algorithm for PET/CT and CT images acquired by different systems at different times. We matched two CT images first (one from standalone CT and the other from PET/CT) that contain affluent anatomical information. Then, we geometrically transformed PET image according to the results of transformation parameters calculated by the previous step. We have used Affine transform to match the target and reference images. For the similarity measure, mutual information was explored. Use of particle swarm algorithm optimized the performance by finding the best matched parameter set within a reasonable amount of time. The results show good agreements of the images between PET/CT and CT. We expect the proposed algorithm can be used not only for PET/CT and CT image registration but also for different multi-modality imaging systems such as SPECT/CT, MRI/PET and so on.

  10. HIGH-RESOLUTION L(Y)SO DETECTORS USING PMT-QUADRANT-SHARING FOR HUMAN & ANIMAL PET CAMERAS.

    Science.gov (United States)

    Ramirez, Rocio A; Liu, Shitao; Liu, Jiguo; Zhang, Yuxuan; Kim, Soonseok; Baghaei, Hossain; Li, Hongdi; Wang, Yu; Wong, Wai-Hoi

    2008-06-01

    We developed high resolution L(Y)SO detectors for human and animal PET applications using Photomultiplier-quadrant-sharing (PQS) technology. The crystal sizes were 1.27 × 1.27 × 10 mm(3) for the animal PQS-blocks and 3.25 × 3.25 × 20 mm(3) for human ones. Polymer mirror film patterns (PMR) were placed between crystals as reflector. The blocks were assembled together using optical grease and wrapped by Teflon tape. The blocks were coupled to regular round PMT's of 19/51 mm in PQS configuration. List-mode data of Ga-68 source (511 KeV) were acquired with our high yield pileup-event recovery (HYPER) electronics and data acquisition software. The high voltage bias was 1100V. Crystal decoding maps and individual crystal energy resolutions were extracted from the data. To investigate the potential imaging resolution of the PET cameras with these blocks, we used GATE (Geant4 Application for Tomographic Emission) simulation package. GATE is a GEANT4 based software toolkit for realistic simulation of PET and SPECT systems. The packing fractions of these blocks were found to be 95.6% and 98.2%. From the decoding maps, all 196 and 225 crystals were clearly identified. The average energy resolutions were 14.0% and 15.6%. For small animal PET systems, the detector ring diameter was 16.5 cm with an axial field of view (AFOV) of 11.8 cm. The simulation data suggests that a reconstructed radial (tangential) spatial resolution of 1.24 (1.25) mm near the center is potentially achievable. For the wholebody human PET systems, the detector ring diameter was 86 cm. The simulation data suggests that a reconstructed radial (tangential) spatial resolution of 3.09(3.38) mm near the center is potentially achievable. From this study we can conclude that PQS design could achieve high spatial resolutions and excellent energy resolutions on human and animal PET systems with substantially lower production costs and inexpensive readout devices. PMID:19946463

  11. Image artifacts from MR-based attenuation correction in clinical, whole-body PET/MRI

    DEFF Research Database (Denmark)

    Keller, Sune H; Holm, Søren; Hansen, Adam E;

    2013-01-01

    Integrated whole-body PET/MRI tomographs have become available. PET/MR imaging has the potential to supplement, or even replace combined PET/CT imaging in selected clinical indications. However, this is true only if methodological pitfalls and image artifacts arising from novel MR-based attenuation...

  12. A high resolution animal PET scanner using compact PS-PMT detectors

    International Nuclear Information System (INIS)

    A new high resolution PET scanner dedicated to animal studies has been designed, built and tested. The system utilizes 240 block detectors, each of which consists of a new compact position-sensitive photomultiplier tube (PS-PMT) and an 8 x 4 BGO array. A total number of 7,680 crystals (480 per ring) are positioned to form a 508 mm diameter of 16 detector rings with 7.2 mm pitch and 114 mm axial field of view (FOV). The system is designed to perform activation studies using a monkey in a sitting position. The data can be acquired in either 2D or 3D mode, where the slice collimators are retracted in 3D mode. The transaxial resolution is 2.6 mm FWHM at the center of the FOV, and the average axial resolution on the axis of the ring is 3.3 mm FWHM in the direct slice and 3.2 mm FWHM in the cross slice. The scatter fraction, sensitivity and count rate performance were evaluated for a 10 cm diameter cylindrical phantom. The total system sensitivity is 2.3 kcps/kBq/ml in 2D mode and 22.8 kcps/kBq/ml in 3D mode. The noise equivalent count rate with 3D mode is equivalent to that with 2D mode at five times higher radioactivity level. The applicable imaging capabilities of the scanner was demonstrated by animal studies with a monkey

  13. (18)F- and (68)Ga-Labeled Neurotensin Peptides for PET Imaging of Neurotensin Receptor 1.

    Science.gov (United States)

    Maschauer, Simone; Einsiedel, Jürgen; Hübner, Harald; Gmeiner, Peter; Prante, Olaf

    2016-07-14

    The neurotensin (NT) receptor-1 (NTS1) is overexpressed in a variety of carcinomas and is therefore an interesting target for imaging with positron emission tomography (PET). The aim of this study was the development of new NT derivatives based on the metabolically stable peptide sequence NLys-Lys-Pro-Tyr-Tle-Leu suitable for PET imaging. The NT peptides were synthesized by solid-phase supported peptide synthesis and elongated with respective chelators (NODA-GA, DOTA) for (68)Ga-labeling or propargylglycine for (18)F-labeling via copper-catalyzed azide-alkyne cycloaddition. Receptor affinities of the peptides for NTS1 were in the range of 19-110 nM. Biodistribution studies using HT29 tumor-bearing mice showed highest tumor uptake for [(68)Ga]6 and [(68)Ga]8 and specific binding in small-animal PET studies. The tumor uptake of (68)Ga-labeled peptides in vivo significantly correlated with the in vitro Ki values for NTS1. [(68)Ga]8 displayed an excellent tumor-to-background ratio and could therefore be considered as an appropriate molecular probe for NTS1 imaging by PET. PMID:27336295

  14. A micro-PET/CT approach using O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine in an experimental animal model of F98 glioma for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Menichetti, L., E-mail: luca.menichetti@ifc.cnr.it [CNR Institute of Clinical Physiology, Pisa (Italy); Petroni, D.; Panetta, D. [CNR Institute of Clinical Physiology, Pisa (Italy); Burchielli, S. [Fondazione CNR/Regione Toscana G. Monasterio, Pisa (Italy); Bortolussi, Silva [Dept. Theoretical and Nuclear Physics, University of Pavia, Pavia (Italy); Matteucci, M. [Scuola Superiore Sant' Anna, Pisa (Italy); Pascali, G.; Del Turco, S. [CNR Institute of Clinical Physiology, Pisa (Italy); Del Guerra, A. [Department of Physics, University of Pisa, Pisa (Italy); Altieri, S. [Dept. Theoretical and Nuclear Physics, University of Pavia, Pavia (Italy); Salvadori, P.A. [CNR Institute of Clinical Physiology, Pisa (Italy)

    2011-12-15

    The present study focuses on a micro-PET/CT application to be used for experimental Boron Neutron Capture Therapy (BNCT), which integrates, in the same frame, micro-CT derived anatomy and PET radiotracer distribution. Preliminary results have demonstrated that {sup 18}F-fluoroethyl-tyrosine (FET)/PET allows the identification of the extent of cerebral lesions in F98 tumor bearing rat. Neutron autoradiography and {alpha}-spectrometry on axial tissues slices confirmed the tumor localization and extraction, after the administration of fructose-boronophenylalanine (BPA). Therefore, FET-PET approach can be used to assess the transport, the net influx, and the accumulation of FET, as an aromatic amino acid analog of BPA, in experimental animal model. Coregistered micro-CT images allowed the accurate morphological localization of the radiotracer distribution and its potential use for experimental BNCT.

  15. ClearPEM: prototype PET device dedicated to breast imaging

    CERN Multimedia

    Joao Varela

    2009-01-01

    Clinical trials have begun in Portugal on a new breast imaging system (ClearPEM) using positron emission tomography (PET). The system, developed by a Portuguese consortium in collaboration with CERN and laboratories participating in the Crystal Clear collaboration, will detect even the smallest tumours and thus help avoid unnecessary biopsies.

  16. Anatomic and functional imaging of tagged molecules in animals

    Science.gov (United States)

    Weisenberger, Andrew G.; Majewski, Stanislaw; Paulus, Michael J.; Gleason, Shaun S.

    2007-04-24

    A novel functional imaging system for use in the imaging of unrestrained and non-anesthetized small animals or other subjects and a method for acquiring such images and further registering them with anatomical X-ray images previously or subsequently acquired. The apparatus comprises a combination of an IR laser profilometry system and gamma, PET and/or SPECT, imaging system, all mounted on a rotating gantry, that permits simultaneous acquisition of positional and orientational information and functional images of an unrestrained subject that are registered, i.e. integrated, using image processing software to produce a functional image of the subject without the use of restraints or anesthesia. The functional image thus obtained can be registered with a previously or subsequently obtained X-ray CT image of the subject. The use of the system described herein permits functional imaging of a subject in an unrestrained/non-anesthetized condition thereby reducing the stress on the subject and eliminating any potential interference with the functional testing that such stress might induce.

  17. Imaging the Gastrointestinal Tract of Small Animals

    OpenAIRE

    Jelicks, Linda A.

    2010-01-01

    Animal models of human diseases are increasingly available and are invaluable for studies of organ pathophysiology. Megacolon, abnormal dilatation of the colon not caused by mechanical obstruction, involves the destruction of the autonomic nervous system innervating the colon. Animal models of megacolon include mouse models of Chagas disease and Hirschprung’s disease. Small animal imaging has become an important research tool and recent advances in preclinical imaging modalities have enhanced...

  18. Simultaneous PET/MRI with 13C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification

    DEFF Research Database (Denmark)

    Hansen, Adam E.; Andersen, Flemming L.; Henriksen, Sarah T.;

    2016-01-01

    Background: Integrated PET/MRI with hyperpolarized 13C magnetic resonance spectroscopic imaging (13C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented for...... and 13C-MRSI phantoms including a NEMA [18F]-FDG phantom, 13C-acetate and 13C-urea sources, and hyperpolarized 13C-pyruvate were imaged repeatedly with PET and/or 13C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total...... number of PET trues; and 13C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. Results: PET and 13C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in...

  19. PET imaging of acute and chronic inflammation in living mice

    International Nuclear Information System (INIS)

    In this study, we evaluated the 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced acute and chronic inflammation in living mice by PET imaging of TNF-α and integrin αvβ3 expression. TPA was topically applied to the right ear of BALB/c mice every other day to create the inflammation model. 64Cu-DOTA-etanercept and 64Cu-DOTA-E{E[c(RGDyK)]2}2 were used for PET imaging of TNF-α and integrin αvβ3 expression in both acute and chronic inflammation. Hematoxylin and eosin staining, ex vivo autoradiography, direct tissue sampling, and immunofluorescence staining were also performed to confirm the non-invasive PET imaging results. The ear thickness increased significantly and the TNF-α level more than tripled after a single TPA challenge. MicroPET imaging using 64Cu-DOTA-etanercept revealed high activity accumulation in the inflamed ear, reaching 11.1 ± 1.3, 13.0 ± 2.0, 10.9 ± 1.4, 10.2 ± 2.2%ID/g at 1, 4, 16, and 24 h post injection, respectively (n = 3). Repeated TPA challenges caused TPA-specific chronic inflammation and reduced 64Cu-DOTA-etanercept uptake due to lowered TNF-α expression. 64Cu-DOTA-E{E[c(RGDyK)]2}2 uptake in the chronically inflamed ears (after four and eight TPA challenges) was significantly higher than in the control ears and those after one TPA challenge. Immunofluorescence staining revealed increased integrin β3 expression, consistent with the non-invasive PET imaging results using 64Cu-DOTA-E{E[c(RGDyK)]2}2 as an integrin αv β3-specific radiotracer. Biodistribution and autoradiography studies further confirmed the quantification capability of microPET imaging. Successful PET imaging of TNF- α expression in acute inflammation and integrin αv β3 expression in chronic inflammation provides the rationale for multiple target evaluation over time to fully understand the inflammation processes. (orig.)

  20. PET imaging of acute and chronic inflammation in living mice

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Qizhen; Cai, Weibo; Li, Zi-Bo; Chen, Kai; He, Lina; Chen, Xiaoyuan [Stanford University School of Medicine, The Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford, CA (United States); Li, Hui-Cheng; Hui, Mizhou [AmProtein Corporation, Camarillo, CA (United States)

    2007-11-15

    In this study, we evaluated the 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced acute and chronic inflammation in living mice by PET imaging of TNF-{alpha} and integrin {alpha}{sub v}{beta}{sub 3} expression. TPA was topically applied to the right ear of BALB/c mice every other day to create the inflammation model. {sup 64}Cu-DOTA-etanercept and {sup 64}Cu-DOTA-E{l_brace}E[c(RGDyK)]{sub 2}{r_brace}{sub 2} were used for PET imaging of TNF-{alpha} and integrin {alpha}{sub v}{beta}{sub 3} expression in both acute and chronic inflammation. Hematoxylin and eosin staining, ex vivo autoradiography, direct tissue sampling, and immunofluorescence staining were also performed to confirm the non-invasive PET imaging results. The ear thickness increased significantly and the TNF-{alpha} level more than tripled after a single TPA challenge. MicroPET imaging using {sup 64}Cu-DOTA-etanercept revealed high activity accumulation in the inflamed ear, reaching 11.1 {+-} 1.3, 13.0 {+-} 2.0, 10.9 {+-} 1.4, 10.2 {+-} 2.2%ID/g at 1, 4, 16, and 24 h post injection, respectively (n = 3). Repeated TPA challenges caused TPA-specific chronic inflammation and reduced {sup 64}Cu-DOTA-etanercept uptake due to lowered TNF-{alpha} expression. {sup 64}Cu-DOTA-E{l_brace}E[c(RGDyK)]{sub 2}{r_brace}{sub 2} uptake in the chronically inflamed ears (after four and eight TPA challenges) was significantly higher than in the control ears and those after one TPA challenge. Immunofluorescence staining revealed increased integrin {beta}{sub 3} expression, consistent with the non-invasive PET imaging results using {sup 64}Cu-DOTA-E{l_brace}E[c(RGDyK)]{sub 2}{r_brace}{sub 2} as an integrin {alpha}{sub v} {beta}{sub 3}-specific radiotracer. Biodistribution and autoradiography studies further confirmed the quantification capability of microPET imaging. Successful PET imaging of TNF- {alpha} expression in acute inflammation and integrin {alpha}{sub v} {beta}{sub 3} expression in chronic inflammation provides

  1. SiliPET: Design of an ultra-high resolution small animal PET scanner based on stacks of semi-conductor detectors

    Science.gov (United States)

    Cesca, N.; Auricchio, N.; Di Domenico, G.; Zavattini, G.; Malaguti, R.; Andritschke, R.; Kanbach, G.; Schopper, F.

    2007-03-01

    We studied with Monte Carlo simulations, using the EGSnrc code, a new scanner for small animal positron emission tomography (PET), based on stacks of double-sided semiconductor detectors. Each stack is composed of planar detectors with dimension 70×60×1 mm 3 and orthogonal strips on both sides with 500 μm pitch to read the two interaction coordinates, the third being the detector number in the stack. Multiple interactions in a stack are discarded. In this way, we achieve a precise determination of the first interaction point of the two 511 keV photons. The reduced dimensions of the scanner also improve the solid angle coverage resulting in a high sensitivity. Preliminary results of scanners based on Si planar detectors are presented and the initial tomographic reconstructions demonstrate very good spatial resolution limited only by the positron range. This suggests that, this is a promising new approach for small animal PET imaging. We are testing some double-sided silicon detectors, equipped with 128 orthogonal p and n strips on opposite sides using VATAGP3 ASIC by IDEAS.

  2. SiliPET: Design of an ultra-high resolution small animal PET scanner based on stacks of semi-conductor detectors

    International Nuclear Information System (INIS)

    We studied with Monte Carlo simulations, using the EGSnrc code, a new scanner for small animal positron emission tomography (PET), based on stacks of double-sided semiconductor detectors. Each stack is composed of planar detectors with dimension 70x60x1 mm3 and orthogonal strips on both sides with 500 μm pitch to read the two interaction coordinates, the third being the detector number in the stack. Multiple interactions in a stack are discarded. In this way, we achieve a precise determination of the first interaction point of the two 511 keV photons. The reduced dimensions of the scanner also improve the solid angle coverage resulting in a high sensitivity. Preliminary results of scanners based on Si planar detectors are presented and the initial tomographic reconstructions demonstrate very good spatial resolution limited only by the positron range. This suggests that, this is a promising new approach for small animal PET imaging. We are testing some double-sided silicon detectors, equipped with 128 orthogonal p and n strips on opposite sides using VATAGP3 ASIC by IDEAS

  3. Cardiovascular PET-CT imaging: a new frontier?

    Science.gov (United States)

    Adamson, P D; Williams, M C; Newby, D E

    2016-07-01

    Cardiovascular positron-emission tomography combined with computed tomography (PET-CT) has recently emerged as an imaging technology with the potential to simultaneously describe both anatomical structures and physiological processes in vivo. The scope for clinical application of this technique is vast, but to date this promise has not been realised. Nonetheless, significant research activity is underway to explore these possibilities and it is likely that the knowledge gained will have important diagnostic and therapeutic implications in due course. This review provides a brief overview of the current state of cardiovascular PET-CT and the likely direction of future developments. PMID:26951964

  4. Application of PET-CT imaging in pediatric oncology

    International Nuclear Information System (INIS)

    Pediatric oncology is one of the important cause of children death. PET-CT, which can provide functional and anatomical images in the same scanning session, has a high sensitivity and specialty in the diagnosis of tumors. During the examination of children, careful preparation and individualized dosage are the keys to make it. PET-CT has a great value in making the personal therapy strategy during the clinical activity, including staging, grading, evaluation of therapy, and the items of prognosis and follow-up. (authors)

  5. Accurate modeling of a DOI capable small animal PET scanner using GATE

    International Nuclear Information System (INIS)

    data confirms that the developed simulation setup is a useful tool for a wide range of research applications. - Highlights: ► We developed an MC model of the Argus (Sedecal) small-animal PET scanner using GATE. ► Validation was performed through comparison between simulated and experimental data. ► Spatial resolution, sensitivity and scatter fraction showed agreement within 7%. ► NEC was in excellent agreement at activities up to 50 MBq in the field of view. ► Image quality was also compared through the NEMA NU-4 phantom

  6. NEMA image quality phantom measurements and attenuation correction in integrated PET/MR hybrid imaging

    OpenAIRE

    Ziegler, Susanne; Jakoby, Bjoern W.; Braun, Harald; Paulus, Daniel H.; Quick, Harald H

    2015-01-01

    Background In integrated PET/MR hybrid imaging the evaluation of PET performance characteristics according to the NEMA standard NU 2–2007 is challenging because of incomplete MR-based attenuation correction (AC) for phantom imaging. In this study, a strategy for CT-based AC of the NEMA image quality (IQ) phantom is assessed. The method is systematically evaluated in NEMA IQ phantom measurements on an integrated PET/MR system. Methods NEMA IQ measurements were performed on the integrated 3.0 T...

  7. PET Quantification of Cerebral Oxygen Metabolism in Small Animals

    OpenAIRE

    Takashi Temma; Kazuhiro Koshino; Tetsuaki Moriguchi; Jun-ichiro Enmi; Hidehiro Iida

    2014-01-01

    Understanding cerebral oxygen metabolism is of great importance in both clinical diagnosis and animal experiments because oxygen is a fundamental source of brain energy and supports brain functional activities. Since small animals such as rats are widely used to study various diseases including cerebral ischemia, cerebrovascular diseases, and neurodegenerative diseases, the development of a noninvasive in vivo measurement method of cerebral oxygen metabolic parameters such as oxygen extractio...

  8. Ready for prime time? Dual tracer PET and SPECT imaging

    OpenAIRE

    Fakhri, Georges El

    2012-01-01

    Dual isotope single photon emission computed tomography (SPECT) and dual tracer positron emission tomography (PET) imaging have great potential in clinical and molecular applications in the pediatric as well as the adult populations in many areas of brain, cardiac, and oncologic imaging as it allows the exploration of different physiological and molecular functions (e.g., perfusion, neurotransmission, metabolism, apoptosis, angiogenesis) under the same physiological and physical conditions. T...

  9. Optimization and characterization of PET scanners for Medical Imaging

    OpenAIRE

    Cucciati,

    2014-01-01

    Positron emission tomography is an imaging technique that appeared to be a valid instrument for cancers detection and neuro-imaging studies. Since first models built during 1960s, an incredible effort has been done by researchers to develop scanners more and more advanced with higher specificity and efficiency. Monte Carlo simulations have shown to be a very important tool during design phase of PET prototypes thanks to their ability to simulate systems with many coupled degrees of freedom, a...

  10. Predicting standard-dose PET image from low-dose PET and multimodal MR images using mapping-based sparse representation

    Science.gov (United States)

    Wang, Yan; Zhang, Pei; An, Le; Ma, Guangkai; Kang, Jiayin; Shi, Feng; Wu, Xi; Zhou, Jiliu; Lalush, David S.; Lin, Weili; Shen, Dinggang

    2016-01-01

    Positron emission tomography (PET) has been widely used in clinical diagnosis for diseases and disorders. To obtain high-quality PET images requires a standard-dose radionuclide (tracer) injection into the human body, which inevitably increases risk of radiation exposure. One possible solution to this problem is to predict the standard-dose PET image from its low-dose counterpart and its corresponding multimodal magnetic resonance (MR) images. Inspired by the success of patch-based sparse representation (SR) in super-resolution image reconstruction, we propose a mapping-based SR (m-SR) framework for standard-dose PET image prediction. Compared with the conventional patch-based SR, our method uses a mapping strategy to ensure that the sparse coefficients, estimated from the multimodal MR images and low-dose PET image, can be applied directly to the prediction of standard-dose PET image. As the mapping between multimodal MR images (or low-dose PET image) and standard-dose PET images can be particularly complex, one step of mapping is often insufficient. To this end, an incremental refinement framework is therefore proposed. Specifically, the predicted standard-dose PET image is further mapped to the target standard-dose PET image, and then the SR is performed again to predict a new standard-dose PET image. This procedure can be repeated for prediction refinement of the iterations. Also, a patch selection based dictionary construction method is further used to speed up the prediction process. The proposed method is validated on a human brain dataset. The experimental results show that our method can outperform benchmark methods in both qualitative and quantitative measures.

  11. A dedicated high resolution PET imager for plant sciences

    CERN Document Server

    Wang, Qiang; Li, Ke; Wen, Jie; Komarov, Sergey; O'Sullivan, Joseph A; Tai, Yuan-Chuan

    2014-01-01

    PET provides in vivo molecular and functional imaging capability that is crucial to studying the interaction of plant with changing environment at the whole-plant level. We have developed a dedicated plant PET imager that features high spatial resolution, housed in a fully controlled environment provided by a plant growth chamber (PGC). The system currently contains two types of detector modules: 84 microPET R4 block detectors with 2.2 mm crystals to provide a large detecting area; and 32 Inveon block detectors with 1.5 mm crystals to provide higher spatial resolution. Outputs of the four microPET block detectors in a modular housing are concatenated by a custom printed circuit board to match the output characteristics of an Inveon detector. All the detectors are read out by QuickSilver electronics. The detector modules are configured to full rings with a 15 cm diameter trans-axial field of view (FOV) for dynamic tomographic imaging of small plants. Potentially, the Inveon detectors can be reconfigured to qua...

  12. The effect, identification and correction of misalignment between PET transmission and emission scans on brain PET imaging

    International Nuclear Information System (INIS)

    Objectives: To study the effect of misalignment between PET transmission and emission scans of brain on brain PET imaging, and the Methods to identify and correct it. Methods: 18F-FDG PET imaging was performed on 8 volunteers. The emission images were reconstructed with attenuation correction after some translations and rotations in the x-axis and transverse plane were given, 1 mm and 1 degree each step, respectively. The 3-D volume fusion of PET emission and transmission scans was used to identify the suspected misalignment on 10 18F-FDG PET brain imaging. Three Methods were used to correct the misalignment. First, to quantitate the amount of the misalignment by 3-D volume registration of PET emission and transmission scans, the emission images were reconstructed with corrected translations and rotations in x-direction and transverse plane. Second, the emission images were reconstructed with mathematic calculation of brain attenuation. Third, 18F-FDG PET brain imaging was redone with careful application of laser alignment. Results: The translations greater than 3 mm in x-direction and the rotations greater than 8 degrees in transverse plane could lead to visible artifacts, which were presented with decreasing radioactivity uptake in the cortex of half cerebrum and in the frontal cortex at the side in the translating or rotating direction, respectively. The 3-D volume fusion of PET emission and transmission scans could identify and quantitate the amount of misalignment between PET emission and transmission scans of brain. The PET emission images reconstructed with corrected misalignment and mathematic calculation of brain attenuation were consistent with redone PET brain imaging. Conclusions: The misalignment between PET transmission and emission scans of brain can lead to visible artifacts. The 3-D volume fusion of PET emission and transmission scans can identify and quantitate the amount of the misalignment. The visible artifacts caused by the misalignment can be

  13. Lung tumor segmentation in PET images using graph cuts.

    Science.gov (United States)

    Ballangan, Cherry; Wang, Xiuying; Fulham, Michael; Eberl, Stefan; Feng, David Dagan

    2013-03-01

    The aim of segmentation of tumor regions in positron emission tomography (PET) is to provide more accurate measurements of tumor size and extension into adjacent structures, than is possible with visual assessment alone and hence improve patient management decisions. We propose a segmentation energy function for the graph cuts technique to improve lung tumor segmentation with PET. Our segmentation energy is based on an analysis of the tumor voxels in PET images combined with a standardized uptake value (SUV) cost function and a monotonic downhill SUV feature. The monotonic downhill feature avoids segmentation leakage into surrounding tissues with similar or higher PET tracer uptake than the tumor and the SUV cost function improves the boundary definition and also addresses situations where the lung tumor is heterogeneous. We evaluated the method in 42 clinical PET volumes from patients with non-small cell lung cancer (NSCLC). Our method improves segmentation and performs better than region growing approaches, the watershed technique, fuzzy-c-means, region-based active contour and tumor customized downhill. PMID:23146420

  14. Preclinical Study on GRPR-Targeted (68)Ga-Probes for PET Imaging of Prostate Cancer.

    Science.gov (United States)

    Sun, Yao; Ma, Xiaowei; Zhang, Zhe; Sun, Ziyan; Loft, Mathias; Ding, Bingbing; Liu, Changhao; Xu, Liying; Yang, Meng; Jiang, Yuxin; Liu, Jianfeng; Xiao, Yuling; Cheng, Zhen; Hong, Xuechuan

    2016-08-17

    Gastrin-releasing peptide receptor (GRPR) targeted positron emission tomography (PET) is a highly promising approach for imaging of prostate cancer (PCa) in small animal models and patients. Developing a GRPR-targeted PET probe with excellent in vivo performance such as high tumor uptake, high contrast, and optimal pharmacokinetics is still very challenging. Herein, a novel bombesin (BBN) analogue (named SCH1) based on JMV594 peptide modified with an 8-amino octanoic acid spacer (AOC) was thus designed and conjugated with the metal chelator 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA). The resulting NODAGA-SCH1 was then radiolabeled with (68)Ga and evaluated for PET imaging of PCa. Compared with (68)Ga-NODAGA-JMV594 probe, (68)Ga-NODAGA-SCH1 exhibited excellent PET/CT imaging properties on PC-3 tumor-bearing nude mice, such as high tumor uptake (5.80 ± 0.42 vs 3.78 ± 0.28%ID/g, 2 h) and high tumor/muscle contrast (16.6 ± 1.50 vs 8.42 ± 0.61%ID/g, 2 h). Importantly, biodistribution data indicated a relatively similar accumulation of (68)Ga-NODAGA-SCH1 was observed in the liver (4.21 ± 0.42%ID/g) and kidney (3.41 ± 0.46%ID/g) suggesting that the clearance is through both the kidney and the liver. Overall, (68)Ga-NODAGA-SCH1 showed promising in vivo properties and is a promising candidate for translation into clinical PET-imaging of PCa patients. PMID:27399868

  15. Simultaneous PET/MR imaging in a human brain PET/MR system in 50 patients-Current state of image quality

    Energy Technology Data Exchange (ETDEWEB)

    Schwenzer, N.F., E-mail: nina.schwenzer@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tuebingen, Tuebingen (Germany); Stegger, L., E-mail: stegger@gmx.net [Department of Nuclear Medicine and European Institute for Molecular Imaging, University of Muenster, Muenster (Germany); Bisdas, S., E-mail: sbisdas@gmail.com [Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls University Tuebingen, Tuebingen (Germany); Schraml, C., E-mail: christina.schraml@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tuebingen, Tuebingen (Germany); Kolb, A., E-mail: armin.kolb@med.uni-tuebingen.de [Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, Department of Preclinical Imaging and Radiopharmacy, Eberhard-Karls University Tuebingen, Tuebingen (Germany); Boss, A., E-mail: Andreas.Boss@usz.ch [Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tuebingen, Tuebingen (Germany); Institute of Diagnostic and Interventional Radiology, University Hospital Zuerich, Zuerich (Switzerland); Mueller, M., E-mail: mark.mueller@med.uni-tuebingen.de [Department of Nuclear Medicine, Eberhard-Karls University Tuebingen, Tuebingen (Germany); and others

    2012-11-15

    Objectives: The present work illustrates the current state of image quality and diagnostic accuracy in a new hybrid BrainPET/MR. Materials and methods: 50 patients with intracranial masses, head and upper neck tumors or neurodegenerative diseases were examined with a hybrid BrainPET/MR consisting of a conventional 3T MR system and an MR-compatible PET insert. Directly before PET/MR, all patients underwent a PET/CT examination with either [{sup 18}F]-FDG, [{sup 11}C]-methionine or [{sup 68}Ga]-DOTATOC. In addition to anatomical MR scans, functional sequences were performed including diffusion tensor imaging (DTI), arterial spin labeling (ASL) and proton-spectroscopy. Image quality score of MR imaging was evaluated using a 4-point-scale. PET data quality was assessed by evaluating FDG-uptake and tumor delineation with [{sup 11}C]-methionine and [{sup 68}Ga]-DOTATOC. FDG uptake quantification accuracy was evaluated by means of ROI analysis (right and left frontal and temporo-occipital lobes). The asymmetry indices and ratios between frontal and occipital ROIs were compared. Results: In 45/50 patients, PET/MR examination was successful. Visual analysis revealed a diagnostic image quality of anatomical MR imaging (mean quality score T2 FSE: 1.27 {+-} 0.54; FLAIR: 1.38 {+-} 0.61). ASL and proton-spectroscopy was possible in all cases. In DTI, dental artifacts lead to one non-diagnostic dataset (mean quality score DTI: 1.32 {+-} 0.69; ASL: 1.10 {+-} 0.31). PET datasets of PET/MR and PET/CT offered comparable tumor delineation with [{sup 11}C]-methionine; additional lesions were found in 2/8 [{sup 68}Ga]-DOTATOC-PET in the PET/MR. Mean asymmetry index revealed a high accordance between PET/MR and PET/CT (1.5 {+-} 2.2% vs. 0.9 {+-} 3.6%; mean ratio (frontal/parieto-occipital) 0.93 {+-} 0.08 vs. 0.96 {+-} 0.05), respectively. Conclusions: The hybrid BrainPET/MR allows for molecular, anatomical and functional imaging with uncompromised MR image quality and a high accordance

  16. Low energy cyclotron production of multivalent transition metals for PET imaging and therapy

    Science.gov (United States)

    Avila-Rodriguez, Miguel Angel

    Recent advances in high-resolution tomographs for small animals require the production of nonconventional long-lived positron emitters to label novel radiopharmaceuticals for PET-based molecular imaging. Radioisotopes with an appropriate half life to match the kinetics of slow biological processes will allow to researchers to study the phamacokinetics of PET ligands over several hours, or even days, on the same animal, with the injection of a single dose. In addition, radionuclides with a suitable half life can potentially be distributed from a central production site making them available in PET facilities that lack an in-house cyclotron. In the last few years there has been a growing interest in the use of PET ligands labeled with radiometals, particularly isotopes of copper, yttrium and zirconium. Future clinical applications of these tracers will require them to be produced reliably and efficiently. This thesis work deals with implementing and optimizing the production of the multivalent transition metals 61,64Cu, 86Y and 89Zr for molecular PET imaging and therapy. Our findings in the production of these radionuclides at high specific activity on an 11 MeV proton-only cyclotron are presented. Local applications of these tracers, including Cu-ATSM for in vivo quantification of hypoxia, synthesis of targeted radiopharmaceuticals using activated esters of DOTA, and a novel development of positron emitting resin microspheres, are also be discussed. As a result of this thesis work, metallic radionuclides are now efficiently produced on a weekly basis in sufficient quality and quantity for collaborating scientists at UW-Madison and external users in other Universities across the country.

  17. Monte Carlo simulation of PET images for injection dose optimization

    Czech Academy of Sciences Publication Activity Database

    Boldyš, Jiří; Dvořák, Jiří; Bělohlávek, O.; Skopalová, M.

    London : Taylor and Francis, 2011 - (Manuel, J.; Tavares, R.; Jorge, N.), s. 1-6 ISBN 978-0-415-68395-1. [VipIMAGE 2011 - third ECCOMAS thematic conference on computational vision and medical image processing. Olhao, Algarve (PT), 12.10.2011-14.10.2011] R&D Projects: GA MŠk(CZ) 1M0572 Institutional research plan: CEZ:AV0Z10750506 Keywords : positron emission tomography * Monte Carlo simulation * biological system modeling * image quality Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2012/ZOI/boldys-monte carlo simulation of pet images for injection dose optimization.pdf

  18. High-resolution image reconstruction for PET using estimated detector response functions

    Science.gov (United States)

    Tohme, Michel S.; Qi, Jinyi

    2007-02-01

    The accuracy of the system model in an iterative reconstruction algorithm greatly affects the quality of reconstructed PET images. For efficient computation in reconstruction, the system model in PET can be factored into a product of geometric projection matrix and detector blurring matrix, where the former is often computed based on analytical calculation, and the latter is estimated using Monte Carlo simulations. In this work, we propose a method to estimate the 2D detector blurring matrix from experimental measurements. Point source data were acquired with high-count statistics in the microPET II scanner using a computer-controlled 2-D motion stage. A monotonically convergent iterative algorithm has been derived to estimate the detector blurring matrix from the point source measurements. The algorithm takes advantage of the rotational symmetry of the PET scanner with the modeling of the detector block structure. Since the resulting blurring matrix stems from actual measurements, it can take into account the physical effects in the photon detection process that are difficult or impossible to model in a Monte Carlo simulation. Reconstructed images of a line source phantom show improved resolution with the new detector blurring matrix compared to the original one from the Monte Carlo simulation. This method can be applied to other small-animal and clinical scanners.

  19. PET molecular imaging in stem cell therapy for neurological diseases

    International Nuclear Information System (INIS)

    Human neurological diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, spinal cord injury and multiple sclerosis are caused by loss of different types of neurons and glial cells in the brain and spinal cord. At present, there are no effective therapies against these disorders. Discovery of the therapeutic potential of stem cells offers new strategies for the treatment of neurological diseases. Direct assessment of stem cells' survival, interaction with the host and impact on neuronal functions after transplantation requires advanced in vivo imaging techniques. Positron emission tomography (PET) is a potential molecular imaging modality to evaluate the viability and function of transplanted tissue or stem cells in the nervous system. This review focuses on PET molecular imaging in stem cell therapy for neurological diseases. (orig.)

  20. PET imaging biomarkers in head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Differding, Sarah; Gregoire, Vincent [Universite Catholique de Louvain, St-Luc University Hospital, Department of Radiation Oncology, and Center for Molecular Imaging, Radiotherapy and Oncology (MIRO), Institut de Recherche Experimentale et Clinique (IREC), Brussels (Belgium); Hanin, Francois-Xavier [Universite Catholique de Louvain, St-Luc University Hospital, Department of Nuclear Medicine, and Center for Molecular Imaging, Radiotherapy and Oncology (MIRO), Institut de Recherche Experimentale et Clinique (IREC), Brussels (Belgium)

    2015-04-01

    In locally advanced head and neck squamous cell carcinoma (HNSCC), the role of imaging becomes more and more critical in the management process. In this framework, molecular imaging techniques such as PET allow noninvasive assessment of a range of tumour biomarkers such as metabolism, hypoxia and proliferation, which can serve different purposes. First, in a pretreatment setting they can influence therapy selection strategies and target delineation for radiation therapy. Second, their predictive and/or prognostic value could help enhance the therapeutic ratio in the management of HNSCC. Third, treatment modification can be performed through the generation of a molecular-based heterogeneous dose distribution with dose escalation to the most resistant parts of the tumour, a concept known as dose painting. Fourth, they are increasingly becoming a tool for monitoring response to therapy. In this review, PET imaging biomarkers used in the routine management of HNSCC or under investigation are discussed. (orig.)

  1. PET molecular imaging in stem cell therapy for neurological diseases

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiachuan; Zhang, Hong [Second Affiliated Hospital of Zhejiang University School of Medicine, Department of Nuclear Medicine, Hangzhou, Zhejiang (China); Zhejiang University, Medical PET Center, Hangzhou (China); Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou (China); Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou (China); Tian, Mei [University of Texas, M.D. Anderson Cancer Center, Department of Experimental Diagnostic Imaging, Houston, TX (United States)

    2011-10-15

    Human neurological diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, spinal cord injury and multiple sclerosis are caused by loss of different types of neurons and glial cells in the brain and spinal cord. At present, there are no effective therapies against these disorders. Discovery of the therapeutic potential of stem cells offers new strategies for the treatment of neurological diseases. Direct assessment of stem cells' survival, interaction with the host and impact on neuronal functions after transplantation requires advanced in vivo imaging techniques. Positron emission tomography (PET) is a potential molecular imaging modality to evaluate the viability and function of transplanted tissue or stem cells in the nervous system. This review focuses on PET molecular imaging in stem cell therapy for neurological diseases. (orig.)

  2. Assessment of MR-compatibility of SiPM PET insert using short optical fiber bundles for small animal research

    Science.gov (United States)

    Kang, H. G.; Hong, S. J.; Ko, G. B.; Yoon, H. S.; Song, I. C.; Rhee, J. T.; Lee, J. S.

    2015-12-01

    Simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) can provide new perspectives in human disease research because of their complementary in-vivo imaging techniques. Previously, we have developed an MR-compatible PET insert based on optical fibers using silicon photomultipliers (SiPM). However when echo planar imaging (EPI) sequence was performed, signal intensity was slowly decreased by -0.9% over the 5.5 minutes and significant geometrical distortion was observed as the PET insert was installed inside an MRI bore, indicating that the PET electronics and its shielding boxes might have been too close to an MR imaging object. In this paper, optical fiber bundles with a length of 54 mm instead of 31 mm were employed to minimize PET interference on MR images. Furthermore, the LYSO crystals with a size of 1.5 × 1.5 × 7.0 mm3 were used instead of 2.47 × 2.74 × 20.0 mm3 for preclinical PET/MR applications. To improve the MR image quality, two receive-only loop coils were used. The effects of the PET insert on the SNR of the MR image either for morphological or advanced MR pulse sequences such as diffusion weighted imaging (DWI), functional MRI (fMRI), and magnetic resonance spectroscopy (MRS) were investigated. The quantitative MR compatibility such as B0 and B1 field homogeneity without PET, with `PET OFF', and with `PET ON' was also evaluated. In conclusion, B0 maps were not affected by the proposed PET insert whereas B1 maps were significantly affected by the PET insert. The advanced MRI sequences such as DWI, EPI, and MRS can be performed without a significant MR image quality degradation.

  3. Assessment of MR-compatibility of SiPM PET insert using short optical fiber bundles for small animal research

    International Nuclear Information System (INIS)

    Simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) can provide new perspectives in human disease research because of their complementary in-vivo imaging techniques. Previously, we have developed an MR-compatible PET insert based on optical fibers using silicon photomultipliers (SiPM). However when echo planar imaging (EPI) sequence was performed, signal intensity was slowly decreased by −0.9% over the 5.5 minutes and significant geometrical distortion was observed as the PET insert was installed inside an MRI bore, indicating that the PET electronics and its shielding boxes might have been too close to an MR imaging object. In this paper, optical fiber bundles with a length of 54 mm instead of 31 mm were employed to minimize PET interference on MR images. Furthermore, the LYSO crystals with a size of 1.5 × 1.5 × 7.0 mm3 were used instead of 2.47 × 2.74 × 20.0 mm3 for preclinical PET/MR applications. To improve the MR image quality, two receive-only loop coils were used. The effects of the PET insert on the SNR of the MR image either for morphological or advanced MR pulse sequences such as diffusion weighted imaging (DWI), functional MRI (fMRI), and magnetic resonance spectroscopy (MRS) were investigated. The quantitative MR compatibility such as B0 and B1 field homogeneity without PET, with 'PET OFF', and with 'PET ON' was also evaluated. In conclusion, B0 maps were not affected by the proposed PET insert whereas B1 maps were significantly affected by the PET insert. The advanced MRI sequences such as DWI, EPI, and MRS can be performed without a significant MR image quality degradation

  4. Imaging optimizations with non-pure and high-energy positron emitters in small animal positron computed tomography

    International Nuclear Information System (INIS)

    The contribution on imaging optimizations with non-pure and high-energy positron emitters in small animal positron emission tomography (PET) covers the following topics: physical fundamentals of PET, mathematical image reconstruction and data analyses, Monte-Carlo simulations and implemented correction scheme, quantification of cascade gamma coincidences based on simulations and measurements, sinogram based corrections, restoration of the spatial resolution, implementation of full corrections.

  5. Classification of bones from MR images in torso PET-MR imaging using a statistical shape model

    NARCIS (Netherlands)

    Ay, Mohammad Reza; Akbarzadeh, Afshin; Ahmadian, Alireza; Zaidi, Habib

    2014-01-01

    There have been exclusive features for hybrid PET/MRI systems in comparison with its PET/CT counterpart in terms of reduction of radiation exposure, improved soft-tissue contrast and truly simultaneous and multi-parametric imaging capabilities. However, quantitative imaging on PET/MR is challenged b

  6. State of the art in both in vitro and in vivo aspects of small animal imaging

    International Nuclear Information System (INIS)

    Full text: In vivo imaging for small animals is dramatically expanding due to the coincidence of mainly three technical factors: 1. the explosion in computer power 2. the enhancement in image processing 3. the accessibility and affordability of digital autoradiography systems and small-animal scanners. Among these imaging techniques let us mention the anatomical imaging techniques such as ultrasonography, X-rays and IRM and the functional imaging radioisotopic techniques SPECT and TEP. The main advantage of the first group of imaging techniques is essentially linked to the high resolution of the anatomical images (with the drawback of the necessity of putting the animal at rest using anaesthesia). The main advantages of SPECT and PET are their high sensitivity and the vast number of functions or metabolism they allow to image. The applications for isotopic functional imaging in small animals are increasing rapidly. Factors contributing to this dramatic expansion include the three previous technical factors plus, at least, three methodological factors: 1. the drug discovery process based on receptor / mechanism of action 2. the increasing number of rodent models of human diseases (SCID mice implanted with human tumors, gene knock-out mice, transgene mice) 3. the advances in isotope and validated tracer availability performances Small animal radioisotopic functional imaging for drug development. In vivo quantification of biological processes to measure the mechanism of action of a potential drug and its concentration at the site of action has become mandatory for developing a drug. Rational and efficient means of confirming mechanisms of action are required. For this purpose, PET and/or SPECT functional - biochemical - molecular imaging in small animals are tools of choice for economical reasons (in the domain of drug development, industry is suffering huge opportunity costs by failing to weed out non-performing new active substances until late phases II and III) and

  7. Radiation protection in an animal research unit with pet: Occupational doses and dose rates produced by animals

    International Nuclear Information System (INIS)

    This study focuses on the occupational doses of technologists working at an Animal Research Unit using PET radiotracers and on the environmental dose rates produced by the animals (mice, rats and monkeys). In particular, whole body and extremity monitoring is reported and related with the workload. The study shows that doses not only depend on the amount of activity injected but also on the type of animals and radiotracers managed. The extremities, with a great variability of the doses received, are the limiting organs as far as regulatory dose limits for workers are concerned. Mean H∗(10) rates in contact and at 20 cm from the animals, when they are handled by the technologist, range from around 1 mSv/h to 20 μSv/h, respectively.

  8. A hybrid algorithm for PET/CT image merger in hybrid scanners

    International Nuclear Information System (INIS)

    To improve the PET image quality of a hybrid PET/CT scanner by merging CT borders with PET texture. PET/CT scanners provide both high-resolution CT images showing anatomical details and PET images of low-resolution physiological information about radiopharmaceutical uptake. Standard smoothing of noisy PET images may further impair PET resolution, reducing small lesion detectability. The CT edge data and the PET texture data were merged using a modified form of an algorithm called HCT (hybrid computed tomography). In merged PET/CT images, each PET pixel value was estimated by iteratively applying a corrected 2D Taylor expansion to each of its eight neighbors. The spatial derivative term was used only near anatomical edges provided by the CT. This counts-preserving algorithm was tested on a special resolution phantom and patient data sets obtained by PET/CT acquisitions. The HCT algorithm provided phantom PET images with sharp borders and improved resolution (≤3 mm as compared to ≥4 mm). HCT increased the signal to background contrast ratios by an average of 61% (40-89%) while maintaining noise reduction similar to the Gaussian filtering standard in PET. In the clinical PET images, HCT allowed for an improved delineation of pulmonary and pelvic lesions and an improved visualization of the brain. A new reconstruction algorithm for merging CT anatomical edge data with functional PET data has been introduced. The algorithm smoothes noisy PET images while retaining sharper edges at corresponding anatomical borders, resulting in an improvement in resolution and contrast ratio. (orig.)

  9. PET/CT imaging of atherosclerotic blood vessel alterations

    International Nuclear Information System (INIS)

    Atherosclerosis is a chronic inflammatory disease of middle sized and large vessels with sequelae comprising the most frequent causes of death in the Western world. Modern imaging modalities are being introduced for the study of atherosclerosis with emphasis on the detection of vulnerable plaques. The hybrid imaging method PET/CT presents advantages for the localization of vulnerable plaques based on the uptake of various molecular imaging agents indicative of inflammatory processes. Using semiquantitative image analysis fluorodeoxyglucose (FDG) uptake in large peripheral vessels has been identified in a series of 21 patients, who were scanned first with the previous generation of PET/CT scanner and subsequently with a new generation apparatus, after a mean interval of 6.5 months. The mean ratio of FDG uptake in the walls of eight large vessels to the blood-pool activity (TBR) was nearly identical in the two PET/CT sessions (TBR1 1.26 versus TBR2 1.28; p=n.s.), indicating independence of the TBR endpoint from the particular instrumentation. (orig.)

  10. Fluorescence-enhanced optical tomography and nuclear imaging system for small animals

    Science.gov (United States)

    Tan, I.-Chih; Lu, Yujie; Darne, Chinmay; Rasmussen, John C.; Zhu, Banghe; Azhdarinia, Ali; Yan, Shikui; Smith, Anne M.; Sevick-Muraca, Eva M.

    2012-03-01

    Near-infrared (NIR) fluorescence is an alternative modality for molecular imaging that has been demonstrated in animals and recently in humans. Fluorescence-enhanced optical tomography (FEOT) using continuous wave or frequency domain photon migration techniques could be used to provide quantitative molecular imaging in vivo if it could be validated against "gold-standard," nuclear imaging modalities, using dual-labeled imaging agents. Unfortunately, developed FEOT systems are not suitable for incorporation with CT/PET/SPECT scanners because they utilize benchtop devices and require a large footprint. In this work, we developed a miniaturized fluorescence imaging system installed in the gantry of the Siemens Inveon PET/CT scanner to enable NIR transillumination measurements. The system consists of a CCD camera equipped with NIR sensitive intensifier, a diode laser controlled by a single board compact controller, a 2-axis galvanometer, and RF circuit modules for homodyne detection of the phase and amplitude of fluorescence signals. The performance of the FEOT system was tested and characterized. A mouse-shaped solid phantom of uniform optical properties with a fluorescent inclusion was scanned using CT, and NIR fluorescence images at several projections were collected. The method of high-order approximation to the radioactive transfer equation was then used to reconstruct the optical images. Dual-labeled agents were also used on a tumor bearing mouse to validate the results of the FEOT against PET/CT image. The results showed that the location of the fluorophore obtained from the FEOT matches the location of tumor obtained from the PET/CT images. Besides validation of FEOT, this hybrid system could allow multimodal molecular imaging (FEOT/PET/CT) for small animal imaging.

  11. Registration of chest PET and CT images. Fusion technique using the PET/Tr image by the respiration compensation

    International Nuclear Information System (INIS)

    The conventional registration of PET images of the chest with CT images is performed by rotating and shifting those images while used median lines and contours on axial images as the reference indexes. For the thoracic and the abdominal regions, therefore, the respiratory movements have prevented us from achieving satisfactory levels of registration reproducibility and accuracy. In order to solve this, we have analyzed respiratory movements of the chest and derived an image fusion method. Respiratory movements of the lung along each axis (X-axis: left-right, Y-axis: dorsoventral, and Z-axis: craniocaudal) during deep breathing were analyzed using CT-3D images. In addition, respiratory movements of the lung and thorax in the Y-axis and Z-axis directions during deep breathing and at rest were also analyzed by using an MR system that is the non-invasive method and allows for acquiring arbitrary tomographic images. Respiratory movements were compensated for on PET images of the lung. Moving average deviations in the Y-axis and Z-axis directions, which were obtained from the analytical result of respiration (30 samples), were used to derive the compensatory values. The analysis of CT-3D images showed that the movements in the X-axis direction were negligible. Registration of PET images with CT images was found useful when it performed on the sagittal planes. The analysis of MR images on sagittal planes revealed that the region extending from the apex of the lung to the posterior wall of the lung was useful for reference indexes for registration. The PET image by the compensation of the respiration transfer difference in the pulmonary hilum division was fusion on the CT image. In the pulmonary hilum division, the improvement in the accuracy of 3.6 mm in the dorsoventral and 6.1 mm in the craniocaudal direction was obtained in comparison with the fusion only of the reference index. The developed image fusion technique compensating the respiratory movements was found to be

  12. 11C-Choline PET/pathology image coregistration in primary localized prostate cancer

    International Nuclear Information System (INIS)

    The aim of this study was to develop a methodology for the comparison of pathology specimens after prostatectomy (post-S) with PET images obtained before surgery (pre-S). This method was used to evaluate the merit of 11C-choline PET/CT for delineation of gross tumour volume (GTV) in prostate cancer (PC). In 28 PC patients, 11C-choline PET/CT was performed before surgery. PET/CT data were coregistered with the pathology specimens. GTV on PET images (GTV-PET) was outlined automatically and corrected manually. Tumour volume in the prostate (TVP) was delineated manually on the pathology specimens. Based on the coregistered PET/pathology images, the following parameters were assessed: SUVmax and SUVmean in the tumoral and nontumoral prostate (NP), GTV-PET (millilitres) and TVP (millilitres). PET/pathology image coregistration was satisfactory. Mean SUVmax in the TVP was lower than in the NP: 5.0 and 5.5, respectively (p = 0.093). Considering the entire prostate, SUVmax was located in the TVP in two patients, in the TVP and NP in 12 patients and exclusively in NP in 14 patients. Partial overlap the TVP and GTV-PET was seen in 71 % of patients, and complete overlap in 4 %. PET/pathology image coregistration can be used for evaluation of different imaging modalities. 11C-Choline PET failed to distinguish tumour from nontumour tissue. (orig.)

  13. {sup 11}C-Choline PET/pathology image coregistration in primary localized prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Grosu, Anca-Ligia; Prokic, Vesna [University of Freiburg, Department of Radiation Oncology, Freiburg (Germany); Technical University of Munich, Department of Radiation Oncology, Munich (Germany); Weirich, Gregor [Technical University of Munich, Institute of Pathology, Munich (Germany); Wendl, Christina; Geinitz, Hans; Molls, Michael [Technical University of Munich, Department of Radiation Oncology, Munich (Germany); Kirste, Simon [University of Freiburg, Department of Radiation Oncology, Freiburg (Germany); Souvatzoglou, Michael; Schwaiger, Markus [Technical University of Munich, Department of Nuclear Medicine, Munich (Germany); Gschwend, Juergen E.; Treiber, Uwe [Technical University of Munich, Department of Urology, Munich (Germany); Weber, Wolfgang A. [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, New York (United States); Krause, Bernd Joachim [Technical University of Munich, Department of Nuclear Medicine, Munich (Germany); University of Rostock, Department of Nuclear Medicine, Rostock (Germany)

    2014-12-15

    The aim of this study was to develop a methodology for the comparison of pathology specimens after prostatectomy (post-S) with PET images obtained before surgery (pre-S). This method was used to evaluate the merit of {sup 11}C-choline PET/CT for delineation of gross tumour volume (GTV) in prostate cancer (PC). In 28 PC patients, {sup 11}C-choline PET/CT was performed before surgery. PET/CT data were coregistered with the pathology specimens. GTV on PET images (GTV-PET) was outlined automatically and corrected manually. Tumour volume in the prostate (TVP) was delineated manually on the pathology specimens. Based on the coregistered PET/pathology images, the following parameters were assessed: SUVmax and SUVmean in the tumoral and nontumoral prostate (NP), GTV-PET (millilitres) and TVP (millilitres). PET/pathology image coregistration was satisfactory. Mean SUVmax in the TVP was lower than in the NP: 5.0 and 5.5, respectively (p = 0.093). Considering the entire prostate, SUVmax was located in the TVP in two patients, in the TVP and NP in 12 patients and exclusively in NP in 14 patients. Partial overlap the TVP and GTV-PET was seen in 71 % of patients, and complete overlap in 4 %. PET/pathology image coregistration can be used for evaluation of different imaging modalities. {sup 11}C-Choline PET failed to distinguish tumour from nontumour tissue. (orig.)

  14. High resolution PET breast imager with improved detection efficiency

    Science.gov (United States)

    Majewski, Stanislaw

    2010-06-08

    A highly efficient PET breast imager for detecting lesions in the entire breast including those located close to the patient's chest wall. The breast imager includes a ring of imaging modules surrounding the imaged breast. Each imaging module includes a slant imaging light guide inserted between a gamma radiation sensor and a photodetector. The slant light guide permits the gamma radiation sensors to be placed in close proximity to the skin of the chest wall thereby extending the sensitive region of the imager to the base of the breast. Several types of photodetectors are proposed for use in the detector modules, with compact silicon photomultipliers as the preferred choice, due to its high compactness. The geometry of the detector heads and the arrangement of the detector ring significantly reduce dead regions thereby improving detection efficiency for lesions located close to the chest wall.

  15. Peritoneal Lymphomatosis Imaged by F-18 FDG PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Park, Eun Kyung; Lee, Se Ryeon; Kim, Young Chul; Oh, Sun Young; Choe, Jae Gol [Korea University Anam Hospital, Seoul (Korea, Republic of)

    2010-06-15

    Peritoneal lymphomatosis is uncommon, but when encountered is associated with aggressive histological subtypes of high-grade lymphoma, such as small-cell, large-cell, mixed large and small cell, non-cleaved, lymphoblastic Burkitt-like, and diffuse large B-cell lymphomas. The CT findings of peritoneal lymphomatosis are linear or nodular peritoneal thickening, retroperitoneal lymphadenopathy, omental and mesenteric involvement with streak-like infiltrations or a bulky mass, bowel wall thickening, hepatosplenomegaly, and ascites. The authors reports report the first FDG PET/CT images of diffuse large B-cell lymphoma of small bowel origin associated with peritoneal lymphomatosis in a 69-year-old man. The lesions demonstrated intense FDG uptake in PET/CT images.

  16. Peritoneal Lymphomatosis Imaged by F-18 FDG PET/CT

    International Nuclear Information System (INIS)

    Peritoneal lymphomatosis is uncommon, but when encountered is associated with aggressive histological subtypes of high-grade lymphoma, such as small-cell, large-cell, mixed large and small cell, non-cleaved, lymphoblastic Burkitt-like, and diffuse large B-cell lymphomas. The CT findings of peritoneal lymphomatosis are linear or nodular peritoneal thickening, retroperitoneal lymphadenopathy, omental and mesenteric involvement with streak-like infiltrations or a bulky mass, bowel wall thickening, hepatosplenomegaly, and ascites. The authors reports report the first FDG PET/CT images of diffuse large B-cell lymphoma of small bowel origin associated with peritoneal lymphomatosis in a 69-year-old man. The lesions demonstrated intense FDG uptake in PET/CT images.

  17. Recent trends in Molecular Imaging : PET/CT in Neurology

    Directory of Open Access Journals (Sweden)

    R P Tripathi

    2015-06-01

    Full Text Available PET/CT is an important molecular imaging technique for the assessment ofneurological disorders. The most widely used radiopharmaceutical for both clinical and research purposes is [18F] 2-fluoro-2-deoxy-D-glucose (FDG. It is extensively used owing to its favourable physical characteristics. It enables depiction of cerebral glucose metabolism, and has thus been used to study various pathological states. Despite this, FDG has its own limitations. This is owing to its limited specificity and high cortical uptake. This has paved the way for the development of several non-FDG PET radiopharmaceuticals. We present the insights gained at our institution, using these radiotracers in the assessment of neurological disease. Our study shows that the use of FDG and non-FDG novel PET radiopharmaceuticals facilitates the early diagnosis, delineation of extent, prognostication and monitoring of therapeutic response in several neuropathological states.PET/CT is an important molecular imaging technique for the assessment ofneurological disorders. The most widely used radiopharmaceutical for both clinicaland research purposes is [18F] 2-fluoro-2-deoxy-D-glucose (FDG. It is extensivelyused owing to its favourable physical characteristics. It enables depiction of cerebralglucose metabolism, and has thus been used to study various pathological states.Despite this, FDG has its own limitations. This is owing to its limited specificity andhigh cortical uptake. This has paved the way for the development of several non-FDGPET radiopharmaceuticals. We present the insights gained at our institution, usingthese radiotracers in the assessment of neurological disease. Our study shows that theuse of FDG and non-FDG novel PET radiopharmaceuticals facilitates the earlydiagnosis, delineation of extent, prognostication and monitoring of therapeuticresponse in several neuropathological states.

  18. Synthesis of fluorine-18 radio-labeled serum albumins for PET blood pool imaging

    International Nuclear Information System (INIS)

    We sought to develop a practical, reproducible and clinically translatable method of radiolabeling serum albumins with fluorine-18 for use as a PET blood pool imaging agent in animals and man. Fluorine-18 radiolabeled fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester, [18F]F-Py-TFP was prepared first by the reaction of its quaternary ammonium triflate precursor with [18F]tetrabutylammonium fluoride ([18F]TBAF) according to a previously published method for peptides, with minor modifications. The incubation of [18F]F-Py-TFP with rat serum albumin (RSA) in phosphate buffer (pH 9) for 15 min at 37–40 °C produced fluorine-18-radiolabeled RSA and the product was purified using a mini-PD MiniTrap G-25 column. The overall radiochemical yield of the reaction was 18–35% (n = 30, uncorrected) in a 90-min synthesis. This procedure, repeated with human serum albumin (HSA), yielded similar results. Fluorine-18-radiolabeled RSA demonstrated prolonged blood retention (biological half-life of 4.8 hours) in healthy awake rats. The distribution of major organ radioactivity remained relatively unchanged during the 4 hour observation periods either by direct tissue counting or by dynamic PET whole-body imaging except for a gradual accumulation of labeled metabolic products in the bladder. This manual method for synthesizing radiolabeled serum albumins uses fluorine-18, a widely available PET radionuclide, and natural protein available in both pure and recombinant forms which could be scaled up for widespread clinical applications. These preclinical biodistribution and PET imaging results indicate that [18F]RSA is an effective blood pool imaging agent in rats and might, as [18F]HSA, prove similarly useful as a clinical imaging agent

  19. Biodistribution and PET imaging of [{sup 18}F]-fluoroadenosine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Alauddin, Mian M. [Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA 90033 (United States)]. E-mail: alauddin@di.mdacc.tmc.edu; Shahinian, Antranik [Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA 90033 (United States); Park, Ryan [Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA 90033 (United States); Tohme, Michael [Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA 90033 (United States); Fissekis, John D. [Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA 90033 (United States); Conti, Peter S. [Department of Radiology, PET Imaging Science Center, University of Southern California, Los Angeles, CA 90033 (United States)

    2007-04-15

    Introduction: Many fluorinated analogues of adenosine nucleoside have been synthesized and studied as potential antitumor and antiviral agents. Earlier, we reported radiosynthesis of 2'-deoxy-2'-[{sup 18}F]fluoro-1-{beta}-D-arabinofuranosyl-adenine ([{sup 18}F]-FAA) and 3'-deoxy-3'-[{sup 18}F]fluoro-1-{beta}-D-xylofuranosyl-adenine ([{sup 18}F]FXA). Now, we report their in vivo studies including blood clearance, biodistribution and micro-PET imaging in tumor-bearing nude mice. Methods: Tumors were grown in 6-week-old athymic nude mice (Harlan, Indianapolis, IN, USA) by inoculation of HT-29 cells, wild-type cells in the left flank and transduced cells with HSV-tk on the right flank. When the tumor was about 1 cm in size, animals were injected with these radiotracers for in vivo studies, including blood clearance, micro-PET imaging and biodistribution. Results: Uptake of [{sup 18}F]FAA in tumor was 3.3-fold higher than blood, with highest uptake in the spleen. Maximum uptake of [{sup 18}F]FXA was observed in the heart compared to other organs. There was no tumor uptake of [{sup 18}F]FXA. Biodistribution results were supported by micro-PET images, which also showed very high uptake of [{sup 18}F]FAA in spleen and visualization of tumors, and high uptake of [{sup 18}F]FXA in the heart. Conclusion: These results suggest that [{sup 18}F]FAA may be useful for tumor imaging, while [{sup 18}F]FXA may have potential as a heart imaging agent with PET.

  20. [Evaluation of new technologies PET/CT nuclear imaging].

    Science.gov (United States)

    Giraldes, Maria Rosário

    2010-01-01

    Nuclear imaging has used initially anatomic and volumetric technologies as CT or MRI. In recent years new dimensions of non invasive studies, as PET, have shown a higher utility in the effectiveness of the treatment. The evaluation of need must be done according to a principle of Horizontal Equity, equal treatment for equal need and of a principle of Vertical Equity, Different treatment, at regional level, according to each hospital level. The evaluation of need has been made according to the Potential Demand by Potential User Groups: diabetes, type 2, (50 years and more); screening colorectal (50 years and more); morbidity by cancer; surgery of lung cancer; cardiology; heart surgery; acute chest pain in the emergency department. In a Macro Perspective need has been evaluated using the Population Estimations for 2007, at municipality level. Relatively to Lisbon and Porto data at locality level has been used, from the 2001 Census. According to Campos, J.R. (2007), in 2006, it existed 1 PET by 1 million inhabitants and after that date 2 more were created (Quadrantes and Hospital ad Luz), belonging to the private sector. Mores 15 PET are needed in the NHS, 1 PET for about 504128 inhabitants. According to The Potential Demand perspective 18 new PET are needed, 15 from the public sector. The private sector will cover progressively the demand. Dorado and Albertino (2002), in Spain, mention that the introduction of this new technique in our Health System must be done slowly due to the cost and complexity. In Portugal exists already 6 PET and this applies also. As a first priority the intervention in Oncology in the IPO (Coimbra). A priority must be given to the University Hospitals of Santa Maria and São João. The Central Hospitals of Viseu and VilaReal/Régua must have also 1 PET. A priority must be given to the interior in order to avoid transports of patients and families. In fourth place the HC Central Lisbon must have also 1 PET, which will go to the New Hospital

  1. PET imaging with 89Zr: From radiochemistry to the clinic

    International Nuclear Information System (INIS)

    The advent of antibody-based cancer therapeutics has led to the concomitant rise in the development of companion diagnostics for these therapies, particularly nuclear imaging agents. A number of radioisotopes have been employed for antibody-based PET and SPECT imaging, notably 64Cu, 124I, 111In, and 99mTc; in recent years, however, the field has increasingly focused on 89Zr, a radiometal with near ideal physical and chemical properties for immunoPET imaging. In the review at hand, we seek to provide a comprehensive portrait of the current state of 89Zr radiochemical and imaging research, including work into the production and purification of the isotope, the synthesis of new chelators, the development of new bioconjugation strategies, the creation of novel 89Zr-based agents for preclinical imaging studies, and the translation of 89Zr-labeled radiopharmaceuticals to the clinic. Particular attention will also be dedicated to emerging trends in the field, 89Zr-based imaging applications using vectors other than antibodies, the comparative advantages and limitations of 89Zr-based imaging compared to that with other isotopes, and areas that would benefit from more extensive investigation. At bottom, it is hoped that this review will provide both the experienced investigator and new scientist with a full and critical overview of this exciting and fast-developing field.

  2. Potential Role of Pet Animals in Household Transmission of Methicillin-Resistant Staphylococcus aureus: A Narrative Review

    OpenAIRE

    Bramble, Manuel; Morris, Daniel; Tolomeo, Pam; Lautenbach, Ebbing

    2011-01-01

    In this narrative review, we found numerous reports suggesting that dogs and cats may play a role in household methicillin-resistant Staphylococcus aureus (MRSA) transmission and recurrent MRSA infection in human contacts. Future work should emphasize elucidating more clearly the prevalence of MRSA in household pets and characterize transmission dynamics of MRSA humans and pet animals.

  3. Motion compensation for PET image reconstruction using deformable tetrahedral meshes

    International Nuclear Information System (INIS)

    Respiratory-induced organ motion is a technical challenge to PET imaging. This motion induces displacements and deformation of the organs tissues, which need to be taken into account when reconstructing the spatial radiation activity. Classical image-based methods that describe motion using deformable image registration (DIR) algorithms cannot fully take into account the non-reproducibility of the respiratory internal organ motion nor the tissue volume variations that occur during breathing. In order to overcome these limitations, various biomechanical models of the respiratory system have been developed in the past decade as an alternative to DIR approaches. In this paper, we describe a new method of correcting motion artefacts in PET image reconstruction adapted to motion estimation models such as those based on the finite element method. In contrast with the DIR-based approaches, the radiation activity was reconstructed on deforming tetrahedral meshes. For this, we have re-formulated the tomographic reconstruction problem by introducing a time-dependent system matrix based calculated using tetrahedral meshes instead of voxelized images. The MLEM algorithm was chosen as the reconstruction method. The simulations performed in this study show that the motion compensated reconstruction based on tetrahedral deformable meshes has the capability to correct motion artefacts. Results demonstrate that, in the case of complex deformations, when large volume variations occur, the developed tetrahedral based method is more appropriate than the classical DIR-based one. This method can be used, together with biomechanical models controlled by external surrogates, to correct motion artefacts in PET images and thus reducing the need for additional internal imaging during the acquisition. (paper)

  4. Performance evaluation of SiPM photodetectors for PET imaging in the presence of magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Espana, S., E-mail: samuel@nuclear.fis.ucm.e [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Fraile, L.M.; Herraiz, J.L.; Udias, J.M. [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Desco, M.; Vaquero, J.J. [Unidad de Medicina y Cirugia Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain)

    2010-02-01

    The multi-pixel photon counter (MPPC) or silicon photomultiplier (SiPM), recently introduced as a solid-state photodetector, consists of an array of Geiger-mode photodiodes (microcells). It is a promising device for PET due to its potential for high photon detection efficiency (PDE) and its foreseeable immunity to magnetic fields. It is also easy to use with simple read-outs, has a high gain and a small size. In this work we evaluate the in field performance of three 1x1 mm{sup 2} (with 100, 400 and 1600 microcells, respectively) and one 6x6 mm{sup 2} (arranged as a 2x2 array) Hamamatsu MPPCs for their use in PET imaging. We examine the dependence of the energy resolution and the gain of these devices on the temperature and reverse bias voltage, when coupled to LYSO scintillator crystals under conditions that one would find in a PET system. We find that the 400 and 1600 microcells models and the 2x2 array are suitable for small-size crystals, like those employed in high resolution small animal scanners. We have confirmed the good performance of these devices up to magnetic fields of 7 T as well as their suitability for performing PET acquisitions in the presence of fast switching gradients and high duty radiofrequency MRI sequences.

  5. Image fusion between whole body FDG PET images and whole body MRI images using a full-automatic mutual information-based multimodality image registration software

    International Nuclear Information System (INIS)

    We attempted image fusion between whole body PET and whole body MRI of thirty patients using a full-automatic mutual information (MI) -based multimodality image registration software and evaluated accuracy of this method and impact of the coregistrated imaging on diagnostic accuracy. For 25 of 30 fused images in body area, translating gaps were within 6 mm in all axes and rotating gaps were within 2 degrees around all axes. In head and neck area, considerably much gaps caused by difference of head inclination at imaging occurred in 16 patients, however these gaps were able to decrease by fused separately. In 6 patients, diagnostic accuracy using PET/MRI fused images was superior compared by PET image alone. This work shows that whole body FDG PET images and whole body MRI images can be automatically fused using MI-based multimodality image registration software accurately and this technique can add useful information when evaluating FDG PET images. (author)

  6. The labelling and animal study of tumor positive imaging agent 5-18F-fluorouracil

    International Nuclear Information System (INIS)

    Objective: To synthesize and label a tumor positive imaging agent 18F-fluorouracil (FU) and the animal study on the product was also undertaken. Methods: 18F-FU was synthesized and labelled. Its biodistribution analysis was done on normal and tumor bearing nude mice. PET imaging was performed on normal and tumor bearing rabbits. Results: HPLC analysis and other quality control test results guaranteed the possibility of animal study and clinical usage of 18F-FU. Biodistribution analysis and PET imaging also demonstrated a high accumulation of the tracer in tumor tissue. Conclusion: 18F-FU is a kind of potential tumor positive imaging agents which can be used to assess the effects of chemotherapy

  7. Evaluation of animal control measures on pet demographics in Santa Clara County, California, 1993–2006

    OpenAIRE

    Kass, Philip H.; Johnson, Karen L.; Hsin-Yi Weng

    2013-01-01

    The measurable benefits of animal control programs are unknown and the aim of this study was to determine the impact of these programs on pet population changes. A prospective cross-sectional study of 1000 households was implemented in 2005 to evaluate characteristics of the owned and unowned population of dogs and cats in Santa Clara County, California. The same population was previously studied 12 years earlier. During this time period, the county instituted in 1994 and then subsequently di...

  8. Analysis of respiratory motion artifacts in PET imaging using respiratory gated PET combined with 4D-CT

    International Nuclear Information System (INIS)

    Reduction of respiratory motion artifacts in PET images was studied using respiratory-gated PET (RGPET) with moving phantom. Especially a method of generating simulated helical CT images from 4D-CT datasets was developed and applied to a respiratory specific RGPET images for more accurate attenuation correction. Using a motion phantom with periodicity of 6 seconds and linear motion amplitude of 26 mm, PET/CT (Discovery ST; CEMS) scans with and without respiratory gating were obtained for one syringe and two vials with each volume of 3, 10, and 30 ml respectively. RPM (Real-Time Position Management, Varian) was used for tracking motion during PET/CT scanning. Ten datasets of RGPET and 4D-CT corresponding to every 10% phase intervals were acquired. From the positions, sizes, and uptake values of each subject on the resultant phase specific PET and CT datasets, the correlation between motion artifacts in PET and CT images and the size of motion relative to the size of subject were analyzed. The center positions of three vials in RGPET and 4D-CT agree well with the actual position within the estimated error. However, volumes of subjects in non-gated PET images increase proportional to relative motion size and were overestimated as much as 250% when the motion amplitude was increased two times larger than the size of the subject. On the contrary, the corresponding maximal uptake value was reduced to about 50%. RGPET is demonstrated to remove respiratory motion artifacts in PET imaging, and moreover, more precise image fusion and more accurate attenuation correction is possible by combining with 4D-CT

  9. In vivo imaging of brain androgen receptors in rats: a [18F]FDHT PET study

    International Nuclear Information System (INIS)

    Introduction: Steroid hormones like androgens play an important role in the development and maintenance of several brain functions. Androgens can act through androgen receptors (AR) in the brain. This study aims to demonstrate the feasibility of positron emission tomography (PET) with 16β-[18F]fluoro-5α-dihydrotestosterone ([18F]FDHT) to image AR expression in the brain. Methods: Male Wistar rats were either orchiectomized to inhibit endogenous androgen production or underwent sham-surgery. Fifteen days after surgery, rats were subjected to a 90-min dynamic [18F]FDHT PET scan with arterial blood sampling. In a subset of orchiectomized rats, 1 mg/kg dihydrotestosterone was co-injected with the tracer in order to saturate the AR. Plasma samples were analyzed for the presence of radioactive metabolites by radio-TLC. Pharmacokinetic modeling was performed to quantify brain kinetics of the tracer. After the PET scan, the animals were terminated for ex-vivo biodistribution. Results: PET imaging and ex vivo biodistribution studies showed low [18F]FDHT uptake in all brain regions, except pituitary. [18F]FDHT uptake in the surrounding cranial bones was high and increased over time. [18F]FDHT was rapidly metabolized in rats. Metabolism was significantly faster in orchiectomized rats than in sham-orchiectomized rats. Quantitative analysis of PET data indicated substantial spill-over of activity from cranial bones into peripheral brain regions, which prevented further analysis of peripheral brain regions. Logan graphical analysis and kinetic modeling using 1- and 2-tissue compartment models showed reversible and homogenously distributed tracer uptake in central brain regions. [18F]FDHT uptake in the brain could not be blocked by endogenous androgens or administration of dihydrotestosterone. Conclusion: The results of this study indicate that imaging of AR availability in rat brain with [18F]FDHT PET is not feasible. The low AR expression in the brain, the rapid metabolism of

  10. Noninvasive Bioluminescence Imaging in Small Animals

    OpenAIRE

    Zinn, Kurt R.; Chaudhuri, Tandra R.; Szafran, April Adams; O’Quinn, Darrell; Weaver, Casey; Dugger, Kari; Lamar, Dale; Kesterson, Robert A.; Wang, Xiangdong; Frank, Stuart J.

    2008-01-01

    There has been a rapid growth of bioluminescence imaging applications in small animal models in recent years, propelled by the availability of instruments, analysis software, reagents, and creative approaches to apply the technology in molecular imaging. Advantages include the sensitivity of the technique as well as its efficiency, relatively low cost, and versatility. Bioluminescence imaging is accomplished by sensitive detection of light emitted following chemical reaction of the luciferase...

  11. Effect of MR contrast agents on quantitative accuracy of PET in combined whole-body PET/MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lois, Cristina [University of Santiago de Compostela, Department of Particle Physics, Santiago de Compostela (Spain); Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela (Spain); Imaging Science Institute, Tuebingen (Germany); Bezrukov, Ilja [Eberhard Karls University, Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens Foundation, Department of Preclinical Imaging and Radiopharmacy, Tuebingen (Germany); Max Plank Institute for Intelligent Systems, Department of Empirical Inference, Tuebingen (Germany); Schmidt, Holger [Eberhard Karls University, Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens Foundation, Department of Preclinical Imaging and Radiopharmacy, Tuebingen (Germany); Eberhard Karls University, Diagnostic and Interventional Radiology, Department of Radiology, Tuebingen (Germany); Schwenzer, Nina; Werner, Matthias K. [Eberhard Karls University, Diagnostic and Interventional Radiology, Department of Radiology, Tuebingen (Germany); Kupferschlaeger, Juergen [Eberhard Karls University, Nuclear Medicine, Department of Radiology, Tuebingen (Germany); Beyer, Thomas [Imaging Science Institute, Tuebingen (Germany); cmi-experts GmbH, Zuerich (Switzerland)

    2012-11-15

    Clinical PET/MR acquisition protocols entail the use of MR contrast agents (MRCA) that could potentially affect PET quantification following MR-based attenuation correction (AC). We assessed the effect of oral and intravenous (IV) MRCA on PET quantification in PET/MR imaging. We employed two MRCA: Lumirem {sup registered} (oral) and Gadovist {sup registered} (IV). First, we determined their reference PET attenuation values using a PET transmission scan (ECAT-EXACT HR+, Siemens) and a CT scan (PET/CT Biograph 16 HI-REZ, Siemens). Second, we evaluated the attenuation of PET signals in the presence of MRCA. Phantoms were filled with clinically relevant concentrations of MRCA in a background of water and {sup 18}F-fluoride, and imaged using a PET/CT scanner (Biograph 16 HI-REZ, Siemens) and a PET/MR scanner (Biograph mMR, Siemens). Third, we investigated the effect of clinically relevant volumes of MRCA on MR-based AC using human pilot data: a patient study employing Gadovist {sup registered} (IV) and a volunteer study employing two different oral MRCA (Lumirem {sup registered} and pineapple juice). MR-based attenuation maps were calculated following Dixon-based fat-water segmentation and an external atlas-based and pattern recognition (AT and PR) algorithm. IV and oral MRCA in clinically relevant concentrations were found to have PET attenuation values similar to those of water. The phantom experiments showed that under clinical conditions IV and oral MRCA did not yield additional attenuation of PET emission signals. Patient scans showed that PET attenuation maps are not biased after the administration of IV MRCA but may be biased, however, after ingestion of iron oxide-based oral MRCA when segmentation-based AC algorithms are used. Alternative AC algorithms, such as AT and PR, or alternative oral contrast agents, such as pineapple juice, can yield unbiased attenuation maps. In clinical PET/MR scenarios MRCA are not expected to lead to markedly increased attenuation

  12. Effect of MR contrast agents on quantitative accuracy of PET in combined whole-body PET/MR imaging

    International Nuclear Information System (INIS)

    Clinical PET/MR acquisition protocols entail the use of MR contrast agents (MRCA) that could potentially affect PET quantification following MR-based attenuation correction (AC). We assessed the effect of oral and intravenous (IV) MRCA on PET quantification in PET/MR imaging. We employed two MRCA: Lumirem registered (oral) and Gadovist registered (IV). First, we determined their reference PET attenuation values using a PET transmission scan (ECAT-EXACT HR+, Siemens) and a CT scan (PET/CT Biograph 16 HI-REZ, Siemens). Second, we evaluated the attenuation of PET signals in the presence of MRCA. Phantoms were filled with clinically relevant concentrations of MRCA in a background of water and 18F-fluoride, and imaged using a PET/CT scanner (Biograph 16 HI-REZ, Siemens) and a PET/MR scanner (Biograph mMR, Siemens). Third, we investigated the effect of clinically relevant volumes of MRCA on MR-based AC using human pilot data: a patient study employing Gadovist registered (IV) and a volunteer study employing two different oral MRCA (Lumirem registered and pineapple juice). MR-based attenuation maps were calculated following Dixon-based fat-water segmentation and an external atlas-based and pattern recognition (AT and PR) algorithm. IV and oral MRCA in clinically relevant concentrations were found to have PET attenuation values similar to those of water. The phantom experiments showed that under clinical conditions IV and oral MRCA did not yield additional attenuation of PET emission signals. Patient scans showed that PET attenuation maps are not biased after the administration of IV MRCA but may be biased, however, after ingestion of iron oxide-based oral MRCA when segmentation-based AC algorithms are used. Alternative AC algorithms, such as AT and PR, or alternative oral contrast agents, such as pineapple juice, can yield unbiased attenuation maps. In clinical PET/MR scenarios MRCA are not expected to lead to markedly increased attenuation of the PET emission signals. MR

  13. Imaging of Scrub Typhus by PET/CT.

    Science.gov (United States)

    Lv, Jing; Liu, Shuai; Pan, Yu; Ju, Huijun; Zhang, Yifan

    2015-10-01

    A 19-year-old man had an unexplained fever, dizziness, headache, fatigue, and pain in the scrotum. An FDG PET/CT imaging was acquired to assess fever of unknown origin. The images showed multiple foci of increased FDG activity in the enlarged lymph nodes in the body. In addition, mildly increased activity in the enlarged spleen and lung bases was also noted. The patient was eventually diagnosed with scrub typhus based on positive results of the Weil-Felix agglutination test, eschar in the scrotum, and effective therapy. PMID:26252322

  14. Investigation of optimization-based reconstruction with an image-total-variation constraint in PET

    Science.gov (United States)

    Zhang, Zheng; Ye, Jinghan; Chen, Buxin; Perkins, Amy E.; Rose, Sean; Sidky, Emil Y.; Kao, Chien-Min; Xia, Dan; Tung, Chi-Hua; Pan, Xiaochuan

    2016-08-01

    Interest remains in reconstruction-algorithm research and development for possible improvement of image quality in current PET imaging and for enabling innovative PET systems to enhance existing, and facilitate new, preclinical and clinical applications. Optimization-based image reconstruction has been demonstrated in recent years of potential utility for CT imaging applications. In this work, we investigate tailoring the optimization-based techniques to image reconstruction for PET systems with standard and non-standard scan configurations. Specifically, given an image-total-variation (TV) constraint, we investigated how the selection of different data divergences and associated parameters impacts the optimization-based reconstruction of PET images. The reconstruction robustness was explored also with respect to different data conditions and activity up-takes of practical relevance. A study was conducted particularly for image reconstruction from data collected by use of a PET configuration with sparsely populated detectors. Overall, the study demonstrates the robustness of the TV-constrained, optimization-based reconstruction for considerably different data conditions in PET imaging, as well as its potential to enable PET configurations with reduced numbers of detectors. Insights gained in the study may be exploited for developing algorithms for PET-image reconstruction and for enabling PET-configuration design of practical usefulness in preclinical and clinical applications.

  15. A 16-channel MR coil for simultaneous PET/MR imaging in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dregely, Isabel [Klinikum rechts der Isar der Technischen Universitaet Muenchen, Nuklearmedizinische Klinik, Munich (Germany); Department of Radiological Sciences, Los Angeles, CA (United States); Lanz, Titus; Mueller, Matthias F. [Rapid Biomedical GmbH, Rimpar (Germany); Metz, Stephan [Klinikum rechts der Isar der Technischen Universitaet Muenchen, Institut fuer diagnostische und interventionelle Radiologie, Munich (Germany); Kuschan, Marika [Klinikum rechts der Isar der Technischen Universitaet Muenchen, Nuklearmedizinische Klinik, Munich (Germany); IMETUM, Technische Universitaet Muenchen, Munich (Germany); Nimbalkar, Manoj; Ziegler, Sibylle I.; Nekolla, Stephan G.; Schwaiger, Markus [Klinikum rechts der Isar der Technischen Universitaet Muenchen, Nuklearmedizinische Klinik, Munich (Germany); Bundschuh, Ralph A. [Klinikum rechts der Isar der Technischen Universitaet Muenchen, Nuklearmedizinische Klinik, Munich (Germany); Universitaetsklinikum Bonn, Nuklearmedizinische Klinik, Bonn (Germany); Haase, Axel [IMETUM, Technische Universitaet Muenchen, Munich (Germany)

    2015-04-01

    To implement and evaluate a dedicated receiver array coil for simultaneous positron emission tomography/magnetic resonance (PET/MR) imaging in breast cancer. A 16-channel receiver coil design was optimized for simultaneous PET/MR imaging. To assess MR performance, the signal-to-noise ratio, parallel imaging capability and image quality was evaluated in phantoms, volunteers and patients and compared to clinical standard protocols. For PET evaluation, quantitative {sup 18} F-FDG PET images of phantoms and seven patients (14 lesions) were compared to images without the coil. In PET image reconstruction, a CT-based template of the coil was combined with the MR-acquired attenuation correction (AC) map of the phantom/patient. MR image quality was comparable to clinical MR-only examinations. PET evaluation in phantoms showed regionally varying underestimation of the standardised uptake value (SUV; mean 22 %) due to attenuation caused by the coil. This was improved by implementing the CT-based coil template in the AC (<2 % SUV underestimation). Patient data indicated that including the coil in the AC increased the SUV values in the lesions (21 ± 9 %). Using a dedicated PET/MR breast coil, state-of-the-art MRI was possible. In PET, accurate quantification and image homogeneity could be achieved if a CT-template of this coil was included in the AC for PET image reconstruction. (orig.)

  16. Bioluminescence imaging in live cells and animals.

    Science.gov (United States)

    Tung, Jack K; Berglund, Ken; Gutekunst, Claire-Anne; Hochgeschwender, Ute; Gross, Robert E

    2016-04-01

    The use of bioluminescent reporters in neuroscience research continues to grow at a rapid pace as their applications and unique advantages over conventional fluorescent reporters become more appreciated. Here, we describe practical methods and principles for detecting and imaging bioluminescence from live cells and animals. We systematically tested various components of our conventional fluorescence microscope to optimize it for long-term bioluminescence imaging. High-resolution bioluminescence images from live neurons were obtained with our microscope setup, which could be continuously captured for several hours with no signs of phototoxicity. Bioluminescence from the mouse brain was also imaged noninvasively through the intact skull with a conventional luminescence imager. These methods demonstrate how bioluminescence can be routinely detected and measured from live cells and animals in a cost-effective way with common reagents and equipment. PMID:27226972

  17. How Phoenix Creates Color Images (Animation)

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation This simple animation shows how a color image is made from images taken by Phoenix. The Surface Stereo Imager captures the same scene with three different filters. The images are sent to Earth in black and white and the color is added by mission scientists. By contrast, consumer digital cameras and cell phones have filters built in and do all of the color processing within the camera itself. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASAaE(TM)s Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  18. PET imaging in pediatric Hodgkin's lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, M.M. [Dept. of Hematology-Oncology, St. Jude Children' s Research Hospital, Memphis, TN (United States); Krasin, M.J. [Dept. of Radiological Sciences, Div. of Radiation Oncology, St. Jude Children' s Research Hospital, Memphis, TN (United States); Kaste, S.C. [Dept. of Radiological Sciences, Div. of Diagnostic Imaging, St. Jude Children' s Research Hospital, Memphis, TN (United States); Dept. of Radiology, Coll. of Medicine, Univ. of Tennessee Health Science Center, Memphis, TN (United States)

    2004-03-01

    Advances in diagnostic imaging technology, especially functional imaging modalities like positron emission tomography (PET), have significantly influenced the staging and treatment approaches used for pediatric Hodgkin's lymphoma. Today, the majority of children and adolescents diagnosed with Hodgkin's lymphoma will be cured following treatment with noncross-resistant combination chemotherapy alone or in combination with low-dose, involved-field radiation. This success produced a greater appreciation of long-term complications related to radiation, chemotherapy, and surgical staging that prompted significant changes in staging and treatment protocols for children and adolescents with Hodgkin's lymphoma. Contemporary treatment for pediatric Hodgkin's lymphoma uses a risk-adapted approach that reduces the number of combination chemotherapy cycles and radiation treatment fields and doses for patients with localized favorable disease presentation. Advances in diagnostic imaging technology have played a critical role in the development of these risk-adapted treatment regimens. The introduction of computed tomography (CT) provided an accurate and non-invasive modality to define nodal involvement below the diaphragm that motivated the change from surgical to clinical staging. The introduction of functional imaging modalities, like positron emission tomography (PET) scanning, provided the means to correlate tumor activity with anatomic features generated by CT and modify treatment based on tumor response. For centers with access to this modality, PET imaging plays an important role in staging, evaluating tumor response, planning radiation treatment fields, and monitoring after completion of therapy for pediatric Hodgkin's lymphoma. (orig.)

  19. New developments in molecular imaging: positron emission tomography time-of-flight (TOF-PET)

    International Nuclear Information System (INIS)

    Positron Emission tomography (PET) in increasingly being used in oncology for the diagnosis and staging of disease, as well as in monitoring response to therapy. One of the last advances in PET is the incorporation of Time-of-Flight (TOF) information, which improves the tomographic reconstruction process and subsequently the quality of the final image. In this work, we explain the principles of PET and the fundamentals of TOF-PET. Clinical images are shown in order to illustrate how TOF-PET improves the detectability of small lesions, particularly in patients with high body mass index. (Author) 20 refs

  20. A PET imaging system dedicated to mammography

    CERN Document Server

    Varela, J

    2007-01-01

    The imaging system Clear-PEM for positron emission mammography, under development within the framework of the Crystal Clear Collaboration at CERN, is presented. The detector is based on pixelized LYSO crystals optically coupled to avalanche photodiodes (APD) and readout by a fast low-noise electronic system. A dedicated digital trigger and data acquisition system is used for on-line selection of coincidence events with high efficiency, large bandwidth and negligible dead-time. The detector module performance was characterized in detail.

  1. MR-based motion correction for PET imaging using wired active MR microcoils in simultaneous PET-MR: Phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chuan; Brady, Thomas J.; El Fakhri, Georges; Ouyang, Jinsong, E-mail: ouyang.jinsong@mgh.harvard.edu [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Ackerman, Jerome L. [Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Petibon, Yoann [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

    2014-04-15

    Purpose: Artifacts caused by head motion present a major challenge in brain positron emission tomography (PET) imaging. The authors investigated the feasibility of using wired active MR microcoils to track head motion and incorporate the measured rigid motion fields into iterative PET reconstruction. Methods: Several wired active MR microcoils and a dedicated MR coil-tracking sequence were developed. The microcoils were attached to the outer surface of an anthropomorphic{sup 18}F-filled Hoffman phantom to mimic a brain PET scan. Complex rotation/translation motion of the phantom was induced by a balloon, which was connected to a ventilator. PET list-mode and MR tracking data were acquired simultaneously on a PET-MR scanner. The acquired dynamic PET data were reconstructed iteratively with and without motion correction. Additionally, static phantom data were acquired and used as the gold standard. Results: Motion artifacts in PET images were effectively removed by wired active MR microcoil based motion correction. Motion correction yielded an activity concentration bias ranging from −0.6% to 3.4% as compared to a bias ranging from −25.0% to 16.6% if no motion correction was applied. The contrast recovery values were improved by 37%–156% with motion correction as compared to no motion correction. The image correlation (mean ± standard deviation) between the motion corrected (uncorrected) images of 20 independent noise realizations and static reference was R{sup 2} = 0.978 ± 0.007 (0.588 ± 0.010, respectively). Conclusions: Wired active MR microcoil based motion correction significantly improves brain PET quantitative accuracy and image contrast.

  2. MR-based motion correction for PET imaging using wired active MR microcoils in simultaneous PET-MR: Phantom study

    International Nuclear Information System (INIS)

    Purpose: Artifacts caused by head motion present a major challenge in brain positron emission tomography (PET) imaging. The authors investigated the feasibility of using wired active MR microcoils to track head motion and incorporate the measured rigid motion fields into iterative PET reconstruction. Methods: Several wired active MR microcoils and a dedicated MR coil-tracking sequence were developed. The microcoils were attached to the outer surface of an anthropomorphic18F-filled Hoffman phantom to mimic a brain PET scan. Complex rotation/translation motion of the phantom was induced by a balloon, which was connected to a ventilator. PET list-mode and MR tracking data were acquired simultaneously on a PET-MR scanner. The acquired dynamic PET data were reconstructed iteratively with and without motion correction. Additionally, static phantom data were acquired and used as the gold standard. Results: Motion artifacts in PET images were effectively removed by wired active MR microcoil based motion correction. Motion correction yielded an activity concentration bias ranging from −0.6% to 3.4% as compared to a bias ranging from −25.0% to 16.6% if no motion correction was applied. The contrast recovery values were improved by 37%–156% with motion correction as compared to no motion correction. The image correlation (mean ± standard deviation) between the motion corrected (uncorrected) images of 20 independent noise realizations and static reference was R2 = 0.978 ± 0.007 (0.588 ± 0.010, respectively). Conclusions: Wired active MR microcoil based motion correction significantly improves brain PET quantitative accuracy and image contrast

  3. Combined micro-PET/micro-CT imaging of lung tumours in SPC-raf and SPC-myc transgenic mice.

    Directory of Open Access Journals (Sweden)

    Thomas Rodt

    Full Text Available INTRODUCTION: SPC-raf and SPC-myc transgenic mice develop disseminated and circumscribed lung adenocarcinoma respectively, allowing for assessment of carcinogenesis and treatment strategies. The purpose of this study was to investigate the technical feasibility, the correlation of initial findings to histology and the administered radiation dose of combined micro-PET/micro-CT in these animal models. MATERIAL AND METHODS: 14 C57BL/6 mice (4 nontransgenic, 4 SPC-raf transgenic, 6 SPC-myc transgenic were examined using micro-CT and (18F-Fluoro-deoxyglucose micro-PET in-vivo. Micro-PET data was corrected for random events and scatter prior to reconstruction with a 3D-FORE/2D-OSEM iterative algorithm. Rigid micro-PET/micro-CT registration was performed. Tumour-to-non-tumour ratios were calculated for different lung regions and focal lesions. Diffuse tumour growth was quantified using a semiautomated micro-CT segmentation routine reported earlier. Regional histologic tumour load was assessed using a 4-point rating scale. Gamma radiation dose was determined using thermoluminescence dosimeters. RESULTS: Micro-CT allowed visualisation of diffuse and circumscribed tumours in SPC-raf and SPC-myc transgenic animals along with morphology, while micro-PET provided information on metabolism, but lacked morphologic detail. Mean tumour-to-non-tumour ratio was 2.47 for circumscribed lesions. No significant correlation could be shown between histological tumour load and tumour-to-nontumour ratio for diffuse tumours in SPC-raf transgenic animals. Calculation of the expected dose based on gamma dosimetry yielded approximately 140 mGy/micro-PET examination additional to approximately 200 mGy due to micro-CT. CONCLUSIONS: Combined micro-PET/micro-CT imaging allows for in-vivo assessment of lung tumours in SPC-raf and SPC-myc transgenic mice. The technique has potential for the evaluation of carcinogenesis and treatment strategies in circumscribed lung tumours.

  4. Combined Micro-PET/Micro-CT Imaging of Lung Tumours in SPC-raf and SPC-myc Transgenic Mice

    Science.gov (United States)

    Rodt, Thomas; Luepke, Matthias; Boehm, Claudia; Hueper, Katja; Halter, Roman; Glage, Silke; Hoy, Ludwig; Wacker, Frank; Borlak, Juergen; von Falck, Christian

    2012-01-01

    Introduction SPC-raf and SPC-myc transgenic mice develop disseminated and circumscribed lung adenocarcinoma respectively, allowing for assessment of carcinogenesis and treatment strategies. The purpose of this study was to investigate the technical feasibility, the correlation of initial findings to histology and the administered radiation dose of combined micro-PET/micro-CT in these animal models. Material and Methods 14 C57BL/6 mice (4 nontransgenic, 4 SPC-raf transgenic, 6 SPC-myc transgenic) were examined using micro-CT and 18F-Fluoro-deoxyglucose micro-PET in-vivo. Micro-PET data was corrected for random events and scatter prior to reconstruction with a 3D-FORE/2D-OSEM iterative algorithm. Rigid micro-PET/micro-CT registration was performed. Tumour-to-non-tumour ratios were calculated for different lung regions and focal lesions. Diffuse tumour growth was quantified using a semiautomated micro-CT segmentation routine reported earlier. Regional histologic tumour load was assessed using a 4-point rating scale. Gamma radiation dose was determined using thermoluminescence dosimeters. Results Micro-CT allowed visualisation of diffuse and circumscribed tumours in SPC-raf and SPC-myc transgenic animals along with morphology, while micro-PET provided information on metabolism, but lacked morphologic detail. Mean tumour-to-non-tumour ratio was 2.47 for circumscribed lesions. No significant correlation could be shown between histological tumour load and tumour-to-nontumour ratio for diffuse tumours in SPC-raf transgenic animals. Calculation of the expected dose based on gamma dosimetry yielded approximately 140 mGy/micro-PET examination additional to approximately 200 mGy due to micro-CT. Conclusions Combined micro-PET/micro-CT imaging allows for in-vivo assessment of lung tumours in SPC-raf and SPC-myc transgenic mice. The technique has potential for the evaluation of carcinogenesis and treatment strategies in circumscribed lung tumours. PMID:23028537

  5. Simultaneous scanning of two mice in a small-animal PET scanner: a simulation-based assessment of the signal degradation

    Science.gov (United States)

    Reilhac, Anthonin; Boisson, Frédéric; Wimberley, Catriona; Parmar, Arvind; Zahra, David; Hamze, Hasar; Davis, Emma; Arthur, Andrew; Bouillot, Caroline; Charil, Arnaud; Grégoire, Marie-Claude

    2016-02-01

    In PET imaging, research groups have recently proposed different experimental set ups allowing multiple animals to be simultaneously imaged in a scanner in order to reduce the costs and increase the throughput. In those studies, the technical feasibility was demonstrated and the signal degradation caused by additional mice in the FOV characterized, however, the impact of the signal degradation on the outcome of a PET study has not yet been studied. Here we thoroughly investigated, using Monte Carlo simulated [18F]FDG and [11C]Raclopride PET studies, different experimental designs for whole-body and brain acquisitions of two mice and assessed the actual impact on the detection of biological variations as compared to a single-mouse setting. First, we extended the validation of the PET-SORTEO Monte Carlo simulation platform for the simultaneous simulation of two animals. Then, we designed [18F]FDG and [11C]Raclopride input mouse models for the simulation of realistic whole-body and brain PET studies. Simulated studies allowed us to accurately estimate the differences in detection between single- and dual-mode acquisition settings that are purely the result of having two animals in the FOV. Validation results showed that PET-SORTEO accurately reproduced the spatial resolution and noise degradations that were observed with actual dual phantom experiments. The simulated [18F]FDG whole-body study showed that the resolution loss due to the off-center positioning of the mice was the biggest contributing factor in signal degradation at the pixel level and a minimal inter-animal distance as well as the use of reconstruction methods with resolution modeling should be preferred. Dual mode acquisition did not have a major impact on ROI-based analysis except in situations where uptake values in organs from the same subject were compared. The simulated [11C]Raclopride study however showed that dual-mice imaging strongly reduced the sensitivity to variations when mice were

  6. The design of an animal PET: flexible geometry for achieving optimal spatial resolution or high sensitivity.

    Science.gov (United States)

    Weber, S; Terstegge, A; Herzog, H; Reinartz, R; Reinhart, P; Rongen, F; Müller-Gärtner, H W; Halling, H

    1997-10-01

    We present the design of a positron emission tomograph (PET) with flexible geometry dedicated to in vivo studies of small animals (TierPET). The scanner uses two pairs of detectors. Each detector consists of 400 small individual yttrium aluminum perovskite (YAP) scintillator crystals of dimensions 2 x 2 x 15 mm3, optically isolated and glued together, which are coupled to position-sensitive photomultiplier tubes (PSPMT's). The detector modules can be moved in a radial direction so that the detector-to-detector spacing can be varied. Special hardware has been built for coincidence detection, position detection, and real-time data acquisition, which is performed by a PC. The single-event data are transferred to workstations where the radioactivity distribution is reconstructed. The dimensions of the crystals and the detector layout are the result of extensive simulations which are described in this report, taking into account sensitivity, spatial resolution and additional parameters like parallax error or scatter effects. For the three-dimensional (3-D) reconstruction a genuine 3-D expectation-maximization (EM)-algorithm which can include the characteristics of the detector system has been implemented. The reconstruction software is flexible and matches the different detector configurations. The main advantage of the proposed animal PET scanner is its high flexibility, allowing the realization of various detector-system configurations. By changing the detector-to-detector spacing, the system is capable of either providing good spatial resolution or high sensitivity for dynamic studies of pharmacokinetics. PMID:9368124

  7. GPU based Monte Carlo for PET image reconstruction: parameter optimization

    International Nuclear Information System (INIS)

    This paper presents the optimization of a fully Monte Carlo (MC) based iterative image reconstruction of Positron Emission Tomography (PET) measurements. With our MC re- construction method all the physical effects in a PET system are taken into account thus superior image quality is achieved in exchange for increased computational effort. The method is feasible because we utilize the enormous processing power of Graphical Processing Units (GPUs) to solve the inherently parallel problem of photon transport. The MC approach regards the simulated positron decays as samples in mathematical sums required in the iterative reconstruction algorithm, so to complement the fast architecture, our work of optimization focuses on the number of simulated positron decays required to obtain sufficient image quality. We have achieved significant results in determining the optimal number of samples for arbitrary measurement data, this allows to achieve the best image quality with the least possible computational effort. Based on this research recommendations can be given for effective partitioning of computational effort into the iterations in limited time reconstructions. (author)

  8. Automatic detection of radioactive fixations in oncology PET images

    International Nuclear Information System (INIS)

    Therapeutic follow-up of patients with cancer is nowadays of main interest in research. Positron Emission Tomography (PET) appears to become a reference exam for monitoring treatment of cancers, particular in lymphoma. This PhD thus deals on the development of a computer aided detection (CAD) tool focused on hardly visible tumors for whole-body 3D PET images. To achieve such a goal, we proposed an approach based on the combination of two classifiers, the Linear Discriminant Analysis (LDA) and the Support Vector Machines, associated with wavelet image features. Each classifier gives a 3D score map quantifying the probability of its voxels to correspond to a tumor. We proposed a 3D evaluation strategy based on the use of simulated images giving the targeted tumor characteristic gold standard. Such database was developed in this PhD from hundred Monte Carlo simulations of the Zuba phantom. It includes hundred images presenting 375 spherical tumors of calibrated contrasts. Results of the CAD obtained from the binary detection maps are promising. They open the perspective of enriching the binary information generally given to the clinician with parametric indices quantifying the pertinence of each detected tumor. (author)

  9. Molecular imaging of gene expression and protein function in vivo with PET and SPECT.

    Science.gov (United States)

    Sharma, Vijay; Luker, Gary D; Piwnica-Worms, David

    2002-10-01

    Molecular imaging is broadly 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. One underlying premise of molecular imaging is that this emerging field is not defined by the imaging technologies that underpin acquisition of the final image per se, but rather is driven by the underlying biological questions. In practice, the choice of imaging modality and probe is usually reduced to choosing between high spatial resolution and high sensitivity to address a given biological system. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) inherently use image-enhancing agents (radiopharmaceuticals) that are synthesized at sufficiently high specific activity to enable use of tracer concentrations of the compound (picomolar to nanomolar) for detecting molecular signals while providing the desired levels of image contrast. The tracer technologies strategically provide high sensitivity for imaging small-capacity molecular systems in vivo (receptors, enzymes, transporters) at a cost of lower spatial resolution than other technologies. We review several significant PET and SPECT advances in imaging receptors (somatostatin receptor subtypes, neurotensin receptor subtypes, alpha(v)beta(3) integrin), enzymes (hexokinase, thymidine kinase), transporters (MDR1 P-glycoprotein, sodium-iodide symporter), and permeation peptides (human immunodeficiency virus type 1 (HIV-1) Tat conjugates), as well as innovative reporter gene constructs (herpes simplex virus 1 thymidine kinase, somatostatin receptor subtype 2, cytosine deaminase) for imaging gene promoter activation and repression, signal transduction pathways, and protein-protein interactions in vivo. PMID:12353250

  10. In vivo PET imaging of brain nicotinic cholinergic receptors

    International Nuclear Information System (INIS)

    Neuronal acetylcholine receptors (nAChRs) are widely distributed throughout the central nervous system where they modulate a number of CNS functions including neurotransmitter release, cognitive function, anxiety, analgesia and control of cerebral blood flow. In the brain, a major subtype is composed of the α4β2 subunit combination. Density of this subtype has been shown to be decreased in patients with neuro-degenerative disease such as Alzheimer and Parkinson's disease (AD and PD), and mutated receptors has been described in some familial epilepsy. Thus, in vivo mapping of the nicotinic nAChRs by Positron Emission Tomography (PET) are of great interest to monitor the evolution of these pathologies and changes in the neuronal biochemistry induced by therapeutic agents. Recently, a new compound, 3-[2(S)-2-azetidinyl-methoxy]pyridine (A-85380) has been synthesised and labelled with fluorine-18, [18F]fluoro-A-85380 (Dolle et al., 1999). The [18F]fluoro-A-85380 has been shown to bind with high affinity t o nAChRs in vitro (Saba et al., 2004), and its toxicity was low and compatible with it s use at tracer dose in human PET studies (Valette, 2002). PET studies in baboons showed that, after in vivo administration of [ 18F]fluoro-A-85380 at a tracer dose, the distribution of the radioactivity in the brain reflect the distribution of the 18F]fluoro-A-8538 0 combined with its low toxicity make possible the imaging of the nicotinic receptor s in human by PET (Bottlaender 2003). Studies were performed in healthy non-smoker volunteers to evaluate the brain kinetics of [18F]fluoro-A-85380 and to assess the quantification of its nAChRs binding in the human brain with PET (Gallezot et a., 2005). The [18F]fluoro-A-85380 was also used in epileptic patients to whom a mutation in the α4 or β2 nAChRs subunit have been identified. We found that, in these patients, the pattern of the brain distribution of the radiotracer was found different when compared to the healthy subjects

  11. Clinical PET-MR Imaging in Breast Cancer and Lung Cancer.

    Science.gov (United States)

    Rice, Samuel L; Friedman, Kent P

    2016-10-01

    Hybrid imaging systems have dramatically improved thoracic oncology patient care over the past 2 decades. PET-MR imaging systems have the potential to further improve imaging of thoracic neoplasms, resulting in diagnostic and therapeutic advantages compared with current MR imaging and PET-computed tomography systems. Increasing soft tissue contrast and lesion sensitivity, improved image registration, reduced radiation exposure, and improved patient convenience are immediate clinical advantages. Multiparametric quantitative imaging capabilities of PET-MR imaging have the potential to improve understanding of the molecular mechanisms of cancer and treatment effects, potentially guiding improvements in diagnosis and therapy. PMID:27593245

  12. PET hypoxia imaging with FAZA: reproducibility at baseline and during fractionated radiotherapy in tumour-bearing mice

    International Nuclear Information System (INIS)

    Tumour hypoxia is linked to treatment resistance. Positron emission tomography (PET) using hypoxia tracers such as fluoroazomycin arabinoside (FAZA) may allow identification of patients with hypoxic tumours and the monitoring of the efficacy of hypoxia-targeting treatment. Since hypoxia PET is characterized by poor image contrast, and tumour hypoxia undergoes spontaneous changes and is affected by therapy, it remains unclear to what extent PET scans are reproducible. Tumour-bearing mice are valuable in the validation of hypoxia PET, but identification of a reliable reference tissue value (blood sample or image-derived muscle value) for repeated scans may be difficult due to the small size of the animal or absence of anatomical information (pure PET). Here tumour hypoxia was monitored over time using repeated PET scans in individual tumour-bearing mice before and during fractionated radiotherapy. Mice bearing human SiHa cervix tumour xenografts underwent a PET scan 3 h following injection of FAZA on two consecutive days before initiation of treatment (baseline) and again following irradiation with four and ten fractions of 2.5 Gy. On the last scan day, mice were given an intraperitoneal injection of pimonidazole (hypoxia marker), tumours were collected and the intratumoral distribution of FAZA (autoradiography) and hypoxia (pimonidazole immunohistology) were determined in cryosections. Tissue section analysis revealed that the intratumoral distribution of FAZA was strongly correlated with the regional density of hypoxic (pimonidazole-positive) cells, even when necrosis was present, suggesting that FAZA PET provides a reliable measure of tumour hypoxia at the time of the scan. PET-based quantification of tumour tracer uptake relative to injected dose showed excellent reproducibility at baseline, whereas normalization using an image-derived nonhypoxic reference tissue (muscle) proved highly unreliable since a valid and reliable reference value could not be determined

  13. Feasibility of using respiration-averaged MR images for attenuation correction of cardiac PET/MR imaging.

    Science.gov (United States)

    Ai, Hua; Pan, Tinsu

    2015-01-01

    Cardiac imaging is a promising application for combined PET/MR imaging. However, current MR imaging protocols for whole-body attenuation correction can produce spatial mismatch between PET and MR-derived attenuation data owing to a disparity between the two modalities' imaging speeds. We assessed the feasibility of using a respiration-averaged MR (AMR) method for attenuation correction of cardiac PET data in PET/MR images. First, to demonstrate the feasibility of motion imaging with MR, we used a 3T MR system and a two-dimensional fast spoiled gradient-recalled echo (SPGR) sequence to obtain AMR images ofa moving phantom. Then, we used the same sequence to obtain AMR images of a patient's thorax under free-breathing conditions. MR images were converted into PET attenuation maps using a three-class tissue segmentation method with two sets of predetermined CT numbers, one calculated from the patient-specific (PS) CT images and the other from a reference group (RG) containing 54 patient CT datasets. The MR-derived attenuation images were then used for attenuation correction of the cardiac PET data, which were compared to the PET data corrected with average CT (ACT) images. In the myocardium, the voxel-by-voxel differences and the differences in mean slice activity between the AMR-corrected PET data and the ACT-corrected PET data were found to be small (less than 7%). The use of AMR-derived attenuation images in place of ACT images for attenuation correction did not affect the summed stress score. These results demonstrate the feasibility of using the proposed SPGR-based MR imaging protocol to obtain patient AMR images and using those images for cardiac PET attenuation correction. Additional studies with more clinical data are warranted to further evaluate the method. PMID:26218995

  14. Physiological imaging with PET and SPECT in Dementia

    International Nuclear Information System (INIS)

    Dementia is a medical problem of increasingly obvious importance. The most common cause of dementia, Alzheimer's disease (AD) accounts for at least 50% of all cases of dementia, with multi-infarct dementia the next most common cause of the syndrome. While the accuracy of diagnosis of AD may range from 80 to 90%, there is currently no laboratory test to confirm the diagnosis. Functional imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) offer diagnostic advantages since brain function is unequivocally disturbed in all dementing illnesses. Both PET and SPECT have been utilized in the study of dementia. While both techniques rely on principles of emission tomography to produce three dimensional maps of injected radiotracers, the differences between positron and single photon emission have important consequences for the practical applications of the two procedures. This briefly reviews the technical differences between PET and SPECT, and discusses how both techniques have been used in our laboratory to elucidate the pathophysiology of dementia. 32 refs., 2 figs

  15. Sparse/Low Rank Constrained Reconstruction for Dynamic PET Imaging.

    Directory of Open Access Journals (Sweden)

    Xingjian Yu

    Full Text Available In dynamic Positron Emission Tomography (PET, an estimate of the radio activity concentration is obtained from a series of frames of sinogram data taken at ranging in duration from 10 seconds to minutes under some criteria. So far, all the well-known reconstruction algorithms require known data statistical properties. It limits the speed of data acquisition, besides, it is unable to afford the separated information about the structure and the variation of shape and rate of metabolism which play a major role in improving the visualization of contrast for some requirement of the diagnosing in application. This paper presents a novel low rank-based activity map reconstruction scheme from emission sinograms of dynamic PET, termed as SLCR representing Sparse/Low Rank Constrained Reconstruction for Dynamic PET Imaging. In this method, the stationary background is formulated as a low rank component while variations between successive frames are abstracted to the sparse. The resulting nuclear norm and l1 norm related minimization problem can also be efficiently solved by many recently developed numerical methods. In this paper, the linearized alternating direction method is applied. The effectiveness of the proposed scheme is illustrated on three data sets.

  16. Lung PET scan

    Science.gov (United States)

    Chest PET scan; Lung positron emission tomography; PET - chest; PET - lung; PET - tumor imaging ... A PET scan requires a small amount of tracer. The tracer is given through a vein (IV), usually on ...

  17. MO-G-17A-01: Innovative High-Performance PET Imaging System for Preclinical Imaging and Translational Researches

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X [University of Texas MD Anderson Cancer Center, Houston, TX (United States); Lou, K [University of Texas MD Anderson Cancer Center, Houston, TX (United States); Rice University, Houston, TX (United States); Deng, Z [Tsinghua University, Beijing (China); Shao, Y

    2014-06-15

    Purpose: To develop a practical and compact preclinical PET with innovative technologies for substantially improved imaging performance required for the advanced imaging applications. Methods: Several key components of detector, readout electronics and data acquisition have been developed and evaluated for achieving leapfrogged imaging performance over a prototype animal PET we had developed. The new detector module consists of an 8×8 array of 1.5×1.5×30 mm{sup 3} LYSO scintillators with each end coupled to a latest 4×4 array of 3×3 mm{sup 2} Silicon Photomultipliers (with ∼0.2 mm insensitive gap between pixels) through a 2.0 mm thick transparent light spreader. Scintillator surface and reflector/coupling were designed and fabricated to reserve air-gap to achieve higher depth-of-interaction (DOI) resolution and other detector performance. Front-end readout electronics with upgraded 16-ch ASIC was newly developed and tested, so as the compact and high density FPGA based data acquisition and transfer system targeting 10M/s coincidence counting rate with low power consumption. The new detector module performance of energy, timing and DOI resolutions with the data acquisition system were evaluated. Initial Na-22 point source image was acquired with 2 rotating detectors to assess the system imaging capability. Results: No insensitive gaps at the detector edge and thus it is capable for tiling to a large-scale detector panel. All 64 crystals inside the detector were clearly separated from a flood-source image. Measured energy, timing, and DOI resolutions are around 17%, 2.7 ns and 1.96 mm (mean value). Point source image is acquired successfully without detector/electronics calibration and data correction. Conclusion: Newly developed advanced detector and readout electronics will be enable achieving targeted scalable and compact PET system in stationary configuration with >15% sensitivity, ∼1.3 mm uniform imaging resolution, and fast acquisition counting rate

  18. MO-G-17A-01: Innovative High-Performance PET Imaging System for Preclinical Imaging and Translational Researches

    International Nuclear Information System (INIS)

    Purpose: To develop a practical and compact preclinical PET with innovative technologies for substantially improved imaging performance required for the advanced imaging applications. Methods: Several key components of detector, readout electronics and data acquisition have been developed and evaluated for achieving leapfrogged imaging performance over a prototype animal PET we had developed. The new detector module consists of an 8×8 array of 1.5×1.5×30 mm3 LYSO scintillators with each end coupled to a latest 4×4 array of 3×3 mm2 Silicon Photomultipliers (with ∼0.2 mm insensitive gap between pixels) through a 2.0 mm thick transparent light spreader. Scintillator surface and reflector/coupling were designed and fabricated to reserve air-gap to achieve higher depth-of-interaction (DOI) resolution and other detector performance. Front-end readout electronics with upgraded 16-ch ASIC was newly developed and tested, so as the compact and high density FPGA based data acquisition and transfer system targeting 10M/s coincidence counting rate with low power consumption. The new detector module performance of energy, timing and DOI resolutions with the data acquisition system were evaluated. Initial Na-22 point source image was acquired with 2 rotating detectors to assess the system imaging capability. Results: No insensitive gaps at the detector edge and thus it is capable for tiling to a large-scale detector panel. All 64 crystals inside the detector were clearly separated from a flood-source image. Measured energy, timing, and DOI resolutions are around 17%, 2.7 ns and 1.96 mm (mean value). Point source image is acquired successfully without detector/electronics calibration and data correction. Conclusion: Newly developed advanced detector and readout electronics will be enable achieving targeted scalable and compact PET system in stationary configuration with >15% sensitivity, ∼1.3 mm uniform imaging resolution, and fast acquisition counting rate capability for

  19. No Pet or Their Person Left Behind: Increasing the Disaster Resilience of Vulnerable Groups through Animal Attachment, Activities and Networks

    Directory of Open Access Journals (Sweden)

    Kirrilly Thompson

    2014-05-01

    Full Text Available Increased vulnerability to natural disasters has been associated with particular groups in the community. This includes those who are considered de facto vulnerable (children, older people, those with disabilities etc. and those who own pets (not to mention pets themselves. The potential for reconfiguring pet ownership from a risk factor to a protective factor for natural disaster survival has been recently proposed. But how might this resilience-building proposition apply to vulnerable members of the community who own pets or other animals? This article addresses this important question by synthesizing information about what makes particular groups vulnerable, the challenges to increasing their resilience and how animals figure in their lives. Despite different vulnerabilities, animals were found to be important to the disaster resilience of seven vulnerable groups in Australia. Animal attachment and animal-related activities and networks are identified as underexplored devices for disseminating or ‘piggybacking’ disaster-related information and engaging vulnerable people in resilience building behaviors (in addition to including animals in disaster planning initiatives in general. Animals may provide the kind of innovative approach required to overcome the challenges in accessing and engaging vulnerable groups. As the survival of humans and animals are so often intertwined, the benefits of increasing the resilience of vulnerable communities through animal attachment is twofold: human and animal lives can be saved together.

  20. No Pet or Their Person Left Behind: Increasing the Disaster Resilience of Vulnerable Groups through Animal Attachment, Activities and Networks.

    Science.gov (United States)

    Thompson, Kirrilly; Every, Danielle; Rainbird, Sophia; Cornell, Victoria; Smith, Bradley; Trigg, Joshua

    2014-01-01

    Increased vulnerability to natural disasters has been associated with particular groups in the community. This includes those who are considered de facto vulnerable (children, older people, those with disabilities etc.) and those who own pets (not to mention pets themselves). The potential for reconfiguring pet ownership from a risk factor to a protective factor for natural disaster survival has been recently proposed. But how might this resilience-building proposition apply to vulnerable members of the community who own pets or other animals? This article addresses this important question by synthesizing information about what makes particular groups vulnerable, the challenges to increasing their resilience and how animals figure in their lives. Despite different vulnerabilities, animals were found to be important to the disaster resilience of seven vulnerable groups in Australia. Animal attachment and animal-related activities and networks are identified as underexplored devices for disseminating or 'piggybacking' disaster-related information and engaging vulnerable people in resilience building behaviors (in addition to including animals in disaster planning initiatives in general). Animals may provide the kind of innovative approach required to overcome the challenges in accessing and engaging vulnerable groups. As the survival of humans and animals are so often intertwined, the benefits of increasing the resilience of vulnerable communities through animal attachment is twofold: human and animal lives can be saved together. PMID:26480038

  1. A device to measure the effects of strong magnetic fields on the image resolution of PET scanners

    CERN Document Server

    Burdette, D; Chesi, E; Clinthorne, N H; Cochran, E; Honscheid, K; Huh, S S; Kagan, H; Knopp, M; Lacasta, C; Mikuz, M; Schmalbrock, P; Studen, A; Weilhammer, P

    2009-01-01

    Very high resolution images can be achieved in small animal PET systems utilizing solid state silicon pad detectors. As these systems approach sub-millimeter resolutions, the range of the positron is becoming the dominant contribution to image blur. The size of the positron range effect depends on the initial positron energy and hence the radioactive tracer used. For higher energy positron emitters, such as and , which are gaining importance in small animal studies, the width of the annihilation point distribution dominates the spatial resolution. This positron range effect can be reduced by embedding the field of view of the PET scanner in a strong magnetic field. In order to confirm this effect experimentally, we developed a high resolution PET instrument based on silicon pad detectors that can operate in a 7 T magnetic field. In this paper, we describe the instrument and present initial results of a study of the effects of magnetic fields up to 7 T on PET image resolution for and point sources.

  2. Molecular imaging of cancer with radiolabeled peptides and PET.

    Science.gov (United States)

    Vāvere, Amy L; Rossin, Raffaella

    2012-06-01

    Radiolabeled peptides hold promise for diagnosis and therapy of cancer as well as for early monitoring of therapy outcomes, patient stratification, etc. This manuscript focuses on the development of peptides labeled with 18F, 64Cu, 68Ga and other positron-emitting radionuclides for PET imaging. The major techniques for radionuclide incorporation are briefly discussed. Then, examples of positron-emitting peptides targeting somatostatin receptors, integrins, gastrin-releasing peptide receptors, vasointestinal peptide receptors, melanocortin 1 receptors and others are reviewed. PMID:22292762

  3. Segmentation of dynamic PET images with kinetic spectral clustering

    International Nuclear Information System (INIS)

    Segmentation is often required for the analysis of dynamic positron emission tomography (PET) images. However, noise and low spatial resolution make it a difficult task and several supervised and unsupervised methods have been proposed in the literature to perform the segmentation based on semi-automatic clustering of the time activity curves of voxels. In this paper we propose a new method based on spectral clustering that does not require any prior information on the shape of clusters in the space in which they are identified. In our approach, the p-dimensional data, where p is the number of time frames, is first mapped into a high dimensional space and then clustering is performed in a low-dimensional space of the Laplacian matrix. An estimation of the bounds for the scale parameter involved in the spectral clustering is derived. The method is assessed using dynamic brain PET images simulated with GATE and results on real images are presented. We demonstrate the usefulness of the method and its superior performance over three other clustering methods from the literature. The proposed approach appears as a promising pre-processing tool before parametric map calculation or ROI-based quantification tasks. (paper)

  4. Noise and physical limits to maximum resolution of PET images

    Energy Technology Data Exchange (ETDEWEB)

    Herraiz, J.L.; Espana, S. [Dpto. Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Vicente, E.; Vaquero, J.J.; Desco, M. [Unidad de Medicina y Cirugia Experimental, Hospital GU ' Gregorio Maranon' , E-28007 Madrid (Spain); Udias, J.M. [Dpto. Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)], E-mail: jose@nuc2.fis.ucm.es

    2007-10-01

    In this work we show that there is a limit for the maximum resolution achievable with a high resolution PET scanner, as well as for the best signal-to-noise ratio, which are ultimately related to the physical effects involved in the emission and detection of the radiation and thus they cannot be overcome with any particular reconstruction method. These effects prevent the spatial high frequency components of the imaged structures to be recorded by the scanner. Therefore, the information encoded in these high frequencies cannot be recovered by any reconstruction technique. Within this framework, we have determined the maximum resolution achievable for a given acquisition as a function of data statistics and scanner parameters, like the size of the crystals or the inter-crystal scatter. In particular, the noise level in the data as a limitation factor to yield high-resolution images in tomographs with small crystal sizes is outlined. These results have implications regarding how to decide the optimal number of voxels of the reconstructed image or how to design better PET scanners.

  5. Pediatric oncologic imaging. A key application of combined PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gatidis, Sergios; La Fougere, C.; Schaefer, J.F. [Universitaetsklinikum Tuebingen (Germany). Abteilung fuer Diagnostische und Interventionelle Radiologie

    2016-04-15

    Pediatric imaging has been identified as a key application of combined whole-body PET/MRI. First studies have revealed the clinical feasibility and possible advantages of PET/MRI over PET/CT and MRI. Besides a significant reduction in radiation exposure of about 50 - 75 %, combined whole-body PET/MRI offers the diagnostic advantage of the multiparametric characterization of pathophysiologic processes and helps reduce the number of necessary imaging studies. However, very few studies focusing on pediatric PET/MRI have been published to date. Additional studies are necessary in order to fully appreciate the clinical impact of this novel method. This review article shall summarize the existing literature concerning pediatric PET/MRI and give insight into the practical experience derived from over 160 pediatric PET/MRI examinations that were performed in Tuebingen.

  6. FDG-PET/CT imaging for staging and radiotherapy treatment planning of head and neck carcinoma

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) has a potential improvement for staging and radiation treatment planning of various tumor sites. We analyzed the use of 18F-fluorodeoxyglucose (FDG)-PET/computed tomography (CT) images for staging and target volume delineation of patients with head and neck carcinoma candidates for radiotherapy. Twenty-two patients candidates for primary radiotherapy, who did not receive any curative surgery, underwent both CT and PET/CT simulation. Gross Tumor Volume (GTV) was contoured on CT (CT-GTV), PET (PET-GTV), and PET/CT images (PET/CT-GTV). The resulting volumes were analyzed and compared. Based on PET/CT, changes in TNM categories and clinical stage occurred in 5/22 cases (22%). The difference between CT-GTV and PET-GTV was not statistically significant (p = 0.2) whereas the difference between the composite volume (PET/CT-GTV) and CT-GTV was statistically significant (p < 0.0001). PET/CT fusion images could have a potential impact on both tumor staging and treatment planning

  7. Monte Carlo simulations versus experimental measurements in a small animal PET system. A comparison in the NEMA NU 4-2008 framework

    Science.gov (United States)

    Popota, F. D.; Aguiar, P.; España, S.; Lois, C.; Udias, J. M.; Ros, D.; Pavia, J.; Gispert, J. D.

    2015-01-01

    In this work a comparison between experimental and simulated data using GATE and PeneloPET Monte Carlo simulation packages is presented. All simulated setups, as well as the experimental measurements, followed exactly the guidelines of the NEMA NU 4-2008 standards using the microPET R4 scanner. The comparison was focused on spatial resolution, sensitivity, scatter fraction and counting rates performance. Both GATE and PeneloPET showed reasonable agreement for the spatial resolution when compared to experimental measurements, although they lead to slight underestimations for the points close to the edge. High accuracy was obtained between experiments and simulations of the system’s sensitivity and scatter fraction for an energy window of 350-650 keV, as well as for the counting rate simulations. The latter was the most complicated test to perform since each code demands different specifications for the characterization of the system’s dead time. Although simulated and experimental results were in excellent agreement for both simulation codes, PeneloPET demanded more information about the behavior of the real data acquisition system. To our knowledge, this constitutes the first validation of these Monte Carlo codes for the full NEMA NU 4-2008 standards for small animal PET imaging systems.

  8. Monte Carlo simulations versus experimental measurements in a small animal PET system. A comparison in the NEMA NU 4-2008 framework

    International Nuclear Information System (INIS)

    In this work a comparison between experimental and simulated data using GATE and PeneloPET Monte Carlo simulation packages is presented. All simulated setups, as well as the experimental measurements, followed exactly the guidelines of the NEMA NU 4-2008 standards using the microPET R4 scanner. The comparison was focused on spatial resolution, sensitivity, scatter fraction and counting rates performance. Both GATE and PeneloPET showed reasonable agreement for the spatial resolution when compared to experimental measurements, although they lead to slight underestimations for the points close to the edge. High accuracy was obtained between experiments and simulations of the system’s sensitivity and scatter fraction for an energy window of 350–650 keV, as well as for the counting rate simulations. The latter was the most complicated test to perform since each code demands different specifications for the characterization of the system’s dead time. Although simulated and experimental results were in excellent agreement for both simulation codes, PeneloPET demanded more information about the behavior of the real data acquisition system. To our knowledge, this constitutes the first validation of these Monte Carlo codes for the full NEMA NU 4-2008 standards for small animal PET imaging systems. (paper)

  9. Developing Methods for Quantitative PET: Application to Multimodal Human and Rat Brain Imaging

    OpenAIRE

    Ye, Hu

    2014-01-01

    Positron Emission Tomography (PET) is a functional medical imaging tool that enables the visualization of radio-labeled biologically active molecules (tracer) distributed inside a living body. PET is also combined with other modalities such as CT and MRI with either software or hardware methods to gain synergy. However numerous technical and biological issues remain to be addressed to improve the utility of PET in multimodal imaging for both clinical and preclinical applications. Patient move...

  10. Evaluation of anesthesia effects on [{sup 18}F]FDG uptake in mouse brain and heart using small animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, Hiroshi E-mail: htoyama@fujita-hu.ac.jp; Ichise, Masanori; Liow, Jeih-San; Vines, Douglass C.; Seneca, Nicholas M.; Modell, Kendra J.; Seidel, Jurgen; Green, Michael V.; Innis, Robert B

    2004-02-01

    This study evaluates effects of anesthesia on {sup 18}F-FDG (FDG) uptake in mouse brain and heart to establish the basic conditions of small animal PET imaging. Prior to FDG injection, 12 mice were anesthetized with isoflurane gas; 11 mice were anesthetized with an intraperitoneal injection of a ketamine/xylazine mixture; and 11 mice were awake. In isoflurane and ketamine/xylazine conditions, FDG brain uptake (%ID/g) was significantly lower than in controls. Conversely, in the isoflurane condition, %ID/g in heart was significantly higher than in controls, whereas heart uptake in ketamine/xylazine mice was significantly lower. Results suggest that anesthesia impedes FDG uptake in mouse brain and affects FDG uptake in heart; however, the effects in the brain and heart differ depending on the type of anesthesia used.

  11. Influence of image reconstruction methods on statistical parametric mapping of brain PET images

    International Nuclear Information System (INIS)

    Objective: Statistic parametric mapping (SPM) was widely recognized as an useful tool in brain function study. The aim of this study was to investigate if imaging reconstruction algorithm of PET images could influence SPM of brain. Methods: PET imaging of whole brain was performed in six normal volunteers. Each volunteer had two scans with true and false acupuncturing. The PET scans were reconstructed using ordered subsets expectation maximization (OSEM) and filtered back projection (FBP) with 3 varied parameters respectively. The images were realigned, normalized and smoothed using SPM program. The difference between true and false acupuncture scans was tested using a matched pair t test at every voxel. Results: (1) SPM corrected multiple comparison (Pcorrecteduncorrected<0.001): SPM derived from the images with different reconstruction method were different. The largest difference, in number and position of the activated voxels, was noticed between FBP and OSEM re- construction algorithm. Conclusions: The method of PET image reconstruction could influence the results of SPM uncorrected multiple comparison. Attention should be paid when the conclusion was drawn using SPM uncorrected multiple comparison. (authors)

  12. Accuracy verification of PET-CT image fusion and its utilization in target delineation of radiotherapy

    International Nuclear Information System (INIS)

    Objective: Evaluate the accuracy of co-registration of PET and CT (PET-CT) images on line with phantom, and utilize it on patients to provide clinical evidence for target delineation in radiotherapy. Methods: A phantom with markers and different volume cylinders was infused with various concentrations of 18FDG, and scanned at 4 mm by PET and CT respectively. After having been transmitted into GE eNTEGRA and treatment planning system (TPS) workstations, the images were fused and reconstructed. The distance between the markers and the errors were monitored in PET and CT images respectively. The volume of cylinder in PET and CT images were measured and compared by certain pixel value proportion deduction method. The same procedure was performed on the pulmonary tumor image in ten patients. Results: eNTEGRA and TPS workstations had a good length linearity, but the fusion error of the latter was markedly greater than the former. Tumors in different volume filled by varying concentrations of 18FDG required different pixel deduction proportion. The cylinder volume of PET and CT images were almost the same, so were the images of pulmonary tumor of ten patients. Conclusions: The accuracy of image co-registration of PET-CT on line may fulfill the clinical demand. Pixel value proportion deduction method can be used for target delineation on PET image. (authors)

  13. Registered error between PET and CT images confirmed by a water model

    International Nuclear Information System (INIS)

    The registered error between PET and CT imaging system was confirmed by a water model simulating clinical cases. A barrel of 6750 mL was filled with 59.2 MBq [18F]-FDG and scanned after 80 min by 2 dimension model PET/CT. The CT images were used to attenuate the PET images. The CT/PET images were obtained by image morphological processing analyses without barrel wall. The relationship of the water image centroids of CT and PET images was established by linear regression analysis, and the registered error between PET and CT image could be computed one slice by one slice. The alignment program was done 4 times following the protocol given by GE Healthcare. Compared with centroids of water CT images, centroids of PET images were shifted to X-axis (0.011slice+0.63) mm, to Y-axis (0.022×slice+1.35) mm. To match CT images, PET images should be translated along X-axis (-2.69±0.15) mm, Y-axis (0.43±0.11) mm, Z-axis (0.86±0.23) mm, and X-axis be rotated by (0.06±0.07)°, Y-axis by (-0.01±0.08)°, and Z-axis by (0.11±0.07)°. So, the systematic registered error was not affected by load and its distribution. By finding the registered error between PET and CT images for coordinate rotation random error, the water model could confirm the registered results of PET-CT system corrected by Alignment parameters. (authors)

  14. Attenuation correction of emission PET images with average CT: Interpolation from breath-hold CT

    International Nuclear Information System (INIS)

    Misregistration resulting from the difference of temporal resolution in PET and CT scans occur frequently in PET/CT imaging, which causes distortion in tumor quantification in PET. Respiration cine average CT (CACT) for PET attenuation correction has been reported to improve the misalignment effectively by several papers. However, the radiation dose to the patient from a four-dimensional CT scan is relatively high. In this study, we propose a method to interpolate respiratory CT images over a respiratory cycle from inhalation and exhalation breath-hold CT images, and use the average CT from the generated CT set for PET attenuation correction. The radiation dose to the patient is reduced using this method. Six cancer patients of various lesion sites underwent routine free-breath helical CT (HCT), respiration CACT, interpolated average CT (IACT), and 18F-FDG PET. Deformable image registration was used to interpolate the middle phases of a respiratory cycle based on the end-inspiration and end-expiration breath-hold CT scans. The average CT image was calculated from the eight interpolated CT image sets of middle respiratory phases and the two original inspiration and expiration CT images. Then the PET images were reconstructed by these three methods for attenuation correction using HCT, CACT, and IACT. Misalignment of PET image using either CACT or IACT for attenuation correction in PET/CT was improved. The difference in standard uptake value (SUV) from tumor in PET images was most significant between the use of HCT and CACT, while the least significant between the use of CACT and IACT. Besides the similar improvement in tumor quantification compared to the use of CACT, using IACT for PET attenuation correction reduces the radiation dose to the patient.

  15. Attenuation correction of emission PET images with average CT: Interpolation from breath-hold CT

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Tzung-Chi [Department of Biomedical Imaging and Radiological Science, China Medical University, Taiwan (China); Zhang, Geoffrey [Department of Radiation Oncology, Moffitt Cancer Center, FL (United States); Chen, Chih-Hao [Department of Nuclear Medicine, Taipei Veterans General Hospital, Taiwan (China); Yang, Bang-Hung [Department of Nuclear Medicine, Taipei Veterans General Hospital, Taiwan (China); Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taiwan (China); Wu, Nien-Yun [Department of Nuclear Medicine, Taipei Veterans General Hospital, Taiwan (China); Wang, Shyh-Jen, E-mail: jwshyh@vghtpe.gov.tw [Department of Nuclear Medicine, Taipei Veterans General Hospital, Taiwan (China); Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taiwan (China); Wu, Tung-Hsin, E-mail: tung@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taiwan (China)

    2011-05-15

    Misregistration resulting from the difference of temporal resolution in PET and CT scans occur frequently in PET/CT imaging, which causes distortion in tumor quantification in PET. Respiration cine average CT (CACT) for PET attenuation correction has been reported to improve the misalignment effectively by several papers. However, the radiation dose to the patient from a four-dimensional CT scan is relatively high. In this study, we propose a method to interpolate respiratory CT images over a respiratory cycle from inhalation and exhalation breath-hold CT images, and use the average CT from the generated CT set for PET attenuation correction. The radiation dose to the patient is reduced using this method. Six cancer patients of various lesion sites underwent routine free-breath helical CT (HCT), respiration CACT, interpolated average CT (IACT), and 18F-FDG PET. Deformable image registration was used to interpolate the middle phases of a respiratory cycle based on the end-inspiration and end-expiration breath-hold CT scans. The average CT image was calculated from the eight interpolated CT image sets of middle respiratory phases and the two original inspiration and expiration CT images. Then the PET images were reconstructed by these three methods for attenuation correction using HCT, CACT, and IACT. Misalignment of PET image using either CACT or IACT for attenuation correction in PET/CT was improved. The difference in standard uptake value (SUV) from tumor in PET images was most significant between the use of HCT and CACT, while the least significant between the use of CACT and IACT. Besides the similar improvement in tumor quantification compared to the use of CACT, using IACT for PET attenuation correction reduces the radiation dose to the patient.

  16. Attenuation correction of emission PET images with average CT: Interpolation from breath-hold CT

    Science.gov (United States)

    Huang, Tzung-Chi; Zhang, Geoffrey; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Wang, Shyh-Jen; Wu, Tung-Hsin

    2011-05-01

    Misregistration resulting from the difference of temporal resolution in PET and CT scans occur frequently in PET/CT imaging, which causes distortion in tumor quantification in PET. Respiration cine average CT (CACT) for PET attenuation correction has been reported to improve the misalignment effectively by several papers. However, the radiation dose to the patient from a four-dimensional CT scan is relatively high. In this study, we propose a method to interpolate respiratory CT images over a respiratory cycle from inhalation and exhalation breath-hold CT images, and use the average CT from the generated CT set for PET attenuation correction. The radiation dose to the patient is reduced using this method. Six cancer patients of various lesion sites underwent routine free-breath helical CT (HCT), respiration CACT, interpolated average CT (IACT), and 18F-FDG