PET and Recycling

OpenAIRE

Funda Sevencan; Songul A. Vaizoglu

2007-01-01

This review aims to clarify the need of decreasing the environmental effects caused by human and draw attention to the increasing environmental effects of plastics wastes. Plastics consist of organic molecules with high density molecules or polymers. Main resources of plastics are the residue of oil rafineries. Several advantages of plastics, have increased the usage continuously. Polyethylene Terephthalate (PET) is the most commonly used plastics. PET is used to protect food, drinking water,...

High value carbon materials from PET recycling

Energy Technology Data Exchange (ETDEWEB)

Parra, J.B.; Ania, C.O.; Arenillas, A.; Rubiera, F.; Pis, J.J

2004-11-15

Poly(ethylene) terephthalate (PET), has become one of the major post-consumer plastic waste. In this work special attention was paid to minimising PET residues and to obtain a high value carbon material. Pyrolysis and subsequent activation of PET from post-consumer soft-drink bottles was performed. Activation was carried out at 925 deg. C under CO{sub 2} atmosphere to different burn-off degrees. Textural characterisation of the samples was carried out by performing N{sub 2} adsorption isotherms at -196 deg. C. The obtained carbons materials were mainly microporous, presenting low meso and macroporosity, and apparent BET surface areas of upto 2500 m{sup 2} g{sup -1}. The capacity of these materials for phenol adsorption and PAHs removal from aqueous solutions was measured and compared with that attained with commercial active carbons. Preliminary tests also showed high hydrogen uptake values, as good as the results obtained with high-tech carbon materials.

Effects of storage temperature and time of antimony release from PET bottles into drinking water in China.

Science.gov (United States)

Qiao, Fei; Lei, Kun; Li, Zicheng; Liu, Qing; Wei, Zhanliang; An, Lihui; Qi, Hongli; Cui, Song

2018-01-01

Antimony (Sb) concentrations were measured in 10 brands of PET bottled drinking water available in supermarkets in China. To simulate general storage habits based on market research, these PET bottles with drinking water were stored for 4 weeks in a lab or a car trunk during the summer. Although the PET package material of brand A had the lowest Sb level (142.71 ± 29.81 μg/g), it showed a significant increase in Sb concentrations when stored in both the car trunk and the lab. There was significant release of Sb from the PET bottles into the water following 24 h of incubation at ≥ 40 °C (40, 50, 60, and 70 °C), especially at 70 °C. The potential health risk of Sb release from PET bottles was calculated based on daily intake values and determined to be acceptable for consumers under normal storage conditions.

Breast cancer detection using high-resolution breast PET compared to whole-body PET or PET/CT

Energy Technology Data Exchange (ETDEWEB)

Kalinyak, Judith E. [Naviscan Inc., San Diego, CA (United States); Berg, Wendie A. [University of Pittsburgh School of Medicine, Magee-Womens Hospital, Pittsburgh, PA (United States); Schilling, Kathy [Boca Raton Regional Hospital, Boca Raton, FL (United States); Madsen, Kathleen S. [Certus International, Inc., St. Louis, MO (United States); Narayanan, Deepa [Naviscan Inc., San Diego, CA (United States); National Cancer Institute, Bethesda, MD (United States); Tartar, Marie [Scripps Clinic, Scripps Green Hospital, La Jolla, CA (United States)

2014-02-15

To compare the performance characteristics of positron emission mammography (PEM) with those of whole-body PET (WBPET) and PET/CT in women with newly diagnosed breast cancer. A total of 178 women consented to PEM for presurgical planning in an IRB-approved protocol and also underwent either WBPET (n = 69) or PET/CT (n = 109) imaging, as per usual care at three centers. Tumor detection sensitivity, positive predictive values, and {sup 18}F-fluorodeoxyglucose (FDG) uptake were compared between the modalities. The effects of tumor size, type, and grade on detection were examined. The chi-squared or Fisher's exact tests were used to compare distributions between groups, and McNemar's test was used to compare distributions for paired data within subject groups, i.e. PEM versus WBPET or PEM versus PET/CT. The mean age of the women was 59 ± 12 years (median 60 years, range 26-89 years), with a mean invasive index tumor size of 1.6 ± 0.8 cm (median 1.5 cm, range 0.5-4.0 cm). PEM detected more index tumors (61/66, 92 %) than WBPET (37/66, 56 %; p < 0.001) or PET/CT (95/109, 87 % vs. 104/109, 95 % for PEM; p < 0.029). Sensitivity for the detection of additional ipsilateral malignancies was also greater with PEM (7/15, 47 %) than with WBPET (1/15, 6.7 %; p = 0.014) or PET/CT (3/23, 13 % vs. 13/23, 57 % for PEM; p = 0.003). Index tumor detection decreased with decreasing invasive tumor size for both WBPET (p = 0.002) and PET/CT (p < 0.001); PEM was not significantly affected (p = 0.20). FDG uptake, quantified in terms of maximum PEM uptake value, was lowest in ductal carcinoma in situ (median 1.5, range 0.7-3.0) and invasive lobular carcinoma (median 1.5, range 0.7-3.4), and highest in grade III invasive ductal carcinoma (median 3.1, range 1.4-12.9). PEM was more sensitive than either WBPET or PET/CT in showing index and additional ipsilateral breast tumors and remained highly sensitive for tumors smaller than 1 cm. (orig.)

Clinical blood flow measurements with O-15 water and Positron Emission Tomography (PET)

International Nuclear Information System (INIS)

Hichwa, R.D.; Watkins, G.L.; Boles Ponto, L.L.

1993-01-01

Traditionally PET chemists have been primarily involved in development and synthesis of radiopharmaceuticals for imaging. If greater clinical utility and research productivity are to be achieved in the PET field, then this role must be expanded to include not just the synthesis of the end product, but also the efficient and timely delivery of the radiopharmaceutical. Hence, the chemist must also consider (1) more automation of synthesis and QC procedures, (2) reduced radiopharmaceutical preparation time with emphasis towards on-line syntheses whenever feasible, (3) integrated cyclotron/chemistry operations, (4) dose delivery schemes to minimize staff exposure while maintaining purity, sterility and apyrogenicity, and (5) technologist/technician operability of all procedures. At the University of Iowa, techniques have been employed to stream-line the production synthesis, delivery, and imaging of O-15 labelled water for determination of tissue blood flow. Automated cyclotron and PET tomograph operation, as well as steady-state production of O-15 water permit a single PET technologist to conduct qualitative blood flow studies on demand for routine or emergency procedures

A Very High Spatial Resolution Detector for Small Animal PET

International Nuclear Information System (INIS)

Kanai Shah, M.S.

2007-01-01

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

THE ANALYSIS OF THE THREAT OF REUSING PET BOTTLES FOR THE STORAGE OF DRINKING WATER

Directory of Open Access Journals (Sweden)

Manuilov A. M.

2017-12-01

Full Text Available Introduction. According to a sociological survey of about 86% of Kharkiv (Ukraine residents reuse PET bottles for a drinking water storing. This type of reuse of PET bottles isn't safe and the results of numerous research unequivocally confirm this assertion. The largest hazard of plastic bottles reuse for drinking water storage is biological film on the internally surface of bottle. This biofilm may contain pathogenic microorganisms which can migrate from biofilm to fresh water. Human, who drinking contaminated water, may drink microorganisms in common with this water. It's very dangerous, because the numerous strains of pathogens may migration in water and infect from gastric-bowel tract to the humans. Scientists from National technical university "Kharkiv polytechnic institute" in common with experts from Mechnikov institute of microbiology and immunology explored this problem and devised the apparatus, which can destroy a biofilm on polymer or another surface. Materials & Methods. The tested apparatus was the electrical device consisting of a block with electrodes, an electronic control, a water pump and a sprinkler for spraying the disinfectant. The electrode was made of 925˚ silver (sterling silver. Water for the preparation of a disinfectant was tap water and wasn't treated additionally. The sprinkler for spraying the disinfectant was placed in the neck of the infected bottle. Disinfectant solution was sprayed inside the bottle for 4 seconds. The water pressure was about 1.5 atmospheres. After that, the sprinkler was removed and the disinfectant was drained. A smear for microbiological composition was taken from three parts of the bottle - the neck, the middle part and the bottom. Growth of microorganisms and their detections was fixed by classic microbiological methods. Results & Discussion. In the article the scheme of the most probable and widespread way of infection of PET-bottles by pathogens and the way of minimization of this

Multiphase contrast-enhanced CT with highly concentrated contrast agent can be used for PET attenuation correction in integrated PET/CT imaging

International Nuclear Information System (INIS)

Aschoff, Philip; Plathow, Christian; Lichy, Matthias P.; Claussen, Claus D.; Pfannenberg, Christina; Beyer, Thomas; Erb, Gunter; Oeksuez, Mehmet Oe.

2012-01-01

State-of-the-art positron emission tomography/computed tomography (PET/CT) systems incorporate multislice CT technology, thus facilitating the acquisition of multiphase, contrast-enhanced CT data as part of integrated PET/CT imaging protocols. We assess the influence of a highly concentrated iodinated contrast medium (CM) on quantification and image quality following CT-based attenuation correction (CT-AC) in PET/CT. Twenty-eight patients with suspected malignant liver lesions were enrolled prospectively. PET/CT was performed 60 min after injection of 400 MBq of 18 F-fluorodeoxyglucose (FDG) and following the biphasic administration of an intravenous CM (400 mg iodine/ml, Iomeron 400). PET images were reconstructed with CT-AC using any of four acquired CT image sets: non-enhanced, pre-contrast (n-PET), arterial phase (art-PET), portal venous phase (pv-PET) and late phase (late-PET). Normal tissue activity and liver lesions were assessed visually and quantitatively on each PET/CT image set. Visual assessment of PET following CT-AC revealed no noticeable difference in image appearance or quality when using any of the four CT data sets for CT-AC. A total of 44 PET-positive liver lesions was identified in 21 of 28 patients. There were no false-negative or false-positive lesions on PET. Mean standardized uptake values (SUV) in 36 evaluable lesions were: 5.5 (n-PET), 5.8 (art-PET), 5.8 (pv-PET) and 5.8 (late-PET), with the highest mean increase in mean SUV of 6%. Mean SUV changes in liver background increased by up to 10% from n-PET to pv-PET. Multiphase CT data acquired with the use of highly concentrated CM can be used for qualitative assessment of liver lesions in torso FDG PET/CT. The influence on quantification of FDG uptake is small and negligible for most clinical applications. (orig.)

High-Resolution PET Detector. Final report

International Nuclear Information System (INIS)

Karp, Joel

2014-01-01

The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface

High Efficiency, Low Cost Scintillators for PET

International Nuclear Information System (INIS)

Kanai Shah

2007-01-01

Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized

Investigation of Antimony Leaching from Bottles (PET into the Bottled Waters in Fars Province

Directory of Open Access Journals (Sweden)

Masoud Noshadi

2015-05-01

Full Text Available Polyethylene Terephthalate (PET is the most common material used in manufacturing mineral water bottles. Antimony trioxide (Sb2O3 used to form the PET containers may pollute water with their ingredients. In this research, graphite furnance atomic absorption spectrometry was used to investigate the effects of storage time (1 to 8 weeks, storage temperature (-20 to 80 °C, pH (6.3 to 8.3, exposure to sunlight, and UV radiation on leaching antimony from PET bottles into the mineral water of 15 bottled water brands available in Fars Province. Concentrations of antimony in the first and second weeks were lower than the maximum standard limit (5 ppb recommended by Iranian regulations. Antimony concentration in one sample (brand A rose above the standard limit after four weeks and in 3 samples (brands A, F, and J with antimony concentrations of 5.48, 5.08, and 5.06 µg/L, respectively exceeded the standard limit after 8 weeks. Sunlight, UV radiation, changes in pH, and storage at temperatures of -20 ℃, 60 ℃, and 80℃ were also found to increase antimony concentrations to levels above the maximum standard limit. Clearly, storing bottled mineral water in ambient conditions may lead to the release of antimony into bottled water, which is a serious threat to public health.

Water Quality Evaluation of PET Bottled Water by Mineral Balance in the Northeast Asian Region: A Case Study of South Korea.

Science.gov (United States)

Houri, Daisuke; Koo, Chung Mo

2015-09-01

The past few years have seen a demand for drinking water in contemporary society with a focus on safety and taste. Mineral water is now marketed as a popular commercial product and, partly due to health concerns, the production. For the study, a comparison was carried out of water samples from 9 types of polyethylene terephthalate (PET) bottled water sold in South Korea as well as from tap water in the cities of Seoul and Chuncheon. These were compared with samples of Japanese PET bottled water in order to determine shared commonalities and identify individual characteristics. To evaluate water quality objectively, we quantified the elements contained in the water samples. Samples were assessed not with the usual sensory evaluation but with the evaluation approach advocated by Hashimoto et al. which employs the Water Index of Taste and the Water Index of Health. The levels of water quality obtained were compared with the "Prerequisites for Tasty Water" and the "Standards for Tasty Water" devised for city water. The PET Bottled water varieties analyzed in this study-Seoksu, Icis, Bong Pyong, Soon Soo 100, Dong Won Saem Mul, GI JANG SOO and DIAMOND-showed the Water Index of Taste ≥ 2.0 and the Water Index of Health ≥ 5.2, which we classified as tasty/healthy water. SamDaSoo and NamiNeral can be classified as tasty water due to their values of the Water Index of Taste ≥ 2.0 and the Water Index of Health water studied here fulfills the "Water Index of Taste," "Water Index of Health," "Standard for Tasty Water" and "Prerequisites for Tasty Water" that Japanese people value for city water. We can conclude that bottled water which meets water quality requirements will be considered good-tasting by a majority of people.

18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters.

Science.gov (United States)

Mhlanga, Joyce C; Carrino, John A; Lodge, Martin; Wang, Hao; Wahl, Richard L

2014-12-01

The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with (18)F-FDG. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological (18)F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73 ± 7.7 years). Six patients served as the control group (53.7 ± 9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r = 0.86. p = 0.007; r = 0.94, p = 0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7 ± 6.6 vs. 32.2 ± 0.4, p = 0.02; 37.5 ± 5.4 vs. 32.2 ± 0.4, p = 0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8 ± 4.2 vs. 18 ± 1.8, p = 0.13; 22.8 ± 5.38 vs. 20.1 ± 1.54, p = 0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9 ± 31.3 vs. 0, p = 0.03). Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted.

PetIGA: A framework for high-performance isogeometric analysis

KAUST Repository

Dalcin, Lisandro; Collier, N.; Vignal, Philippe; Cortes, Adriano Mauricio; Calo, Victor M.

2016-01-01

We present PetIGA, a code framework to approximate the solution of partial differential equations using isogeometric analysis. PetIGA can be used to assemble matrices and vectors which come from a Galerkin weak form, discretized with Non-Uniform Rational B-spline basis functions. We base our framework on PETSc, a high-performance library for the scalable solution of partial differential equations, which simplifies the development of large-scale scientific codes, provides a rich environment for prototyping, and separates parallelism from algorithm choice. We describe the implementation of PetIGA, and exemplify its use by solving a model nonlinear problem. To illustrate the robustness and flexibility of PetIGA, we solve some challenging nonlinear partial differential equations that include problems in both solid and fluid mechanics. We show strong scaling results on up to 40964096 cores, which confirm the suitability of PetIGA for large scale simulations.

PetIGA: A framework for high-performance isogeometric analysis

KAUST Repository

Dalcin, L.

2016-05-25

We present PetIGA, a code framework to approximate the solution of partial differential equations using isogeometric analysis. PetIGA can be used to assemble matrices and vectors which come from a Galerkin weak form, discretized with Non-Uniform Rational B-spline basis functions. We base our framework on PETSc, a high-performance library for the scalable solution of partial differential equations, which simplifies the development of large-scale scientific codes, provides a rich environment for prototyping, and separates parallelism from algorithm choice. We describe the implementation of PetIGA, and exemplify its use by solving a model nonlinear problem. To illustrate the robustness and flexibility of PetIGA, we solve some challenging nonlinear partial differential equations that include problems in both solid and fluid mechanics. We show strong scaling results on up to 40964096 cores, which confirm the suitability of PetIGA for large scale simulations.

NiftyPET: a High-throughput Software Platform for High Quantitative Accuracy and Precision PET Imaging and Analysis.

Science.gov (United States)

Markiewicz, Pawel J; Ehrhardt, Matthias J; Erlandsson, Kjell; Noonan, Philip J; Barnes, Anna; Schott, Jonathan M; Atkinson, David; Arridge, Simon R; Hutton, Brian F; Ourselin, Sebastien

2018-01-01

We present a standalone, scalable and high-throughput software platform for PET image reconstruction and analysis. We focus on high fidelity modelling of the acquisition processes to provide high accuracy and precision quantitative imaging, especially for large axial field of view scanners. All the core routines are implemented using parallel computing available from within the Python package NiftyPET, enabling easy access, manipulation and visualisation of data at any processing stage. The pipeline of the platform starts from MR and raw PET input data and is divided into the following processing stages: (1) list-mode data processing; (2) accurate attenuation coefficient map generation; (3) detector normalisation; (4) exact forward and back projection between sinogram and image space; (5) estimation of reduced-variance random events; (6) high accuracy fully 3D estimation of scatter events; (7) voxel-based partial volume correction; (8) region- and voxel-level image analysis. We demonstrate the advantages of this platform using an amyloid brain scan where all the processing is executed from a single and uniform computational environment in Python. The high accuracy acquisition modelling is achieved through span-1 (no axial compression) ray tracing for true, random and scatter events. Furthermore, the platform offers uncertainty estimation of any image derived statistic to facilitate robust tracking of subtle physiological changes in longitudinal studies. The platform also supports the development of new reconstruction and analysis algorithms through restricting the axial field of view to any set of rings covering a region of interest and thus performing fully 3D reconstruction and corrections using real data significantly faster. All the software is available as open source with the accompanying wiki-page and test data.

New perspective in high tech radiotherapy planning using PET/CT images (Radiation oncologist's view on PET/CT usage)

International Nuclear Information System (INIS)

Hadjieva, T.; Bildirev, N.; Koleva, I.; Zahariev, Z.; Vasileva, V.; Encheva, E.; Sultanov, B.

2010-01-01

Biological images provided by 18F-FDG PET in combination with structural X ray picture currently offer the most accurate available information on tumour staging, curative antitumour effect for prognosis, impairment of organ function after treatment, as well as primary tumour detection in unknown primary metastatic disease. The authors as radiation oncologists critically have analyzed numerous clinical trials and two guidelines to prove PET/ CT benefit in radiotherapy practice. At present they found lack of scientific evidence to confirm that patient outcomes are superior as a result of the use of PET in RT planning. PET/CT offers a best image for tumour delineation only in some cases of lung cancer, mediastinal lymph nodes and malignant lymphomas. 11C methionin PET adds additional information on postoperative MRI image for brain tumours. Inflammation as postradiation phenomenon, as well as physiological organ movements leads to false-positive PET signal. High tech radiotherapy methods require delineation on precise images given after multidisciplinary team expertise - a practice that is possible only in clinical trials, These unsolved problems have raised many ethical challenges in medical, scientific and social aspect, if wide and routine use of FDG-PET u PET/CT is advocated. (authors)

Poster - 01: LabPET II Pixelated APD-Based PET Scanner for High-Resolution Preclinical Imaging

Energy Technology Data Exchange (ETDEWEB)

Lecomte, Roger; Arpin, Louis; Beaudoin, Jean-François; Bergeron, Mélanie; Bouchard, Jonathan; Bouziri, Haithem; Cadorette, Jules; Gaudin, Émilie; Jürgensen, Nadia; Koua, Konin Calliste; Trépanier, Pierre-Yves Lauzier; Leroux, Jean-Daniel; Loignon-Houle, Francis; Njejimana, Larissa; Paillé, Maxime; Paulin, Caroline; Pepin, Catherine; Pratte, Jean-François; Samson, Arnaud; Thibaudeau, Christian [Université de Sherbrooke, Université de Sherbrooke, CIMS/CRCHUS, Université de Sherbrooke, Université de Sherbrooke, Université de Sherbrooke, CIMS/CRCHUS, Université de Sherbrooke, Université de Sherbrooke, 3IT, Université de Sherbrooke, Novalgo Inc., Université de Sherbrooke, Université de Sherbrooke, CIMS/CRCHUS, 3IT, Université de Sherbrooke, Université de Sherbrooke, Université de Sherbrooke, Université de Sherbrooke, 3IT, Université de Sherbrooke (Canada); and others

2016-08-15

Purpose: LabPET II is a new generation APD-based PET scanner designed to achieve sub-mm spatial resolution using truly pixelated detectors and highly integrated parallel front-end processing electronics. Methods: The basic element uses a 4×8 array of 1.12×1.12 mm{sup 2} Lu{sub 1.9}Y{sub 0.1}SiO{sub 5}:Ce (LYSO) scintillator pixels with one-to-one coupling to a 4×8 pixelated monolithic APD array mounted on a ceramic carrier. Four detector arrays are mounted on a daughter board carrying two flip-chip, 64-channel, mixed-signal, application-specific integrated circuits (ASIC) on the backside interfacing to two detector arrays each. Fully parallel signal processing was implemented in silico by encoding time and energy information using a dual-threshold Time-over-Threshold (ToT) scheme. The self-contained 128-channel detector module was designed as a generic component for ultra-high resolution PET imaging of small to medium-size animals. Results: Energy and timing performance were optimized by carefully setting ToT thresholds to minimize the noise/slope ratio. ToT spectra clearly show resolved 511 keV photopeak and Compton edge with ToT resolution well below 10%. After correction for nonlinear ToT response, energy resolution is typically 24±2% FWHM. Coincidence time resolution between opposing 128-channel modules is below 4 ns FWHM. Initial imaging results demonstrate that 0.8 mm hot spots of a Derenzo phantom can be resolved. Conclusion: A new generation PET scanner featuring truly pixelated detectors was developed and shown to achieve a spatial resolution approaching the physical limit of PET. Future plans are to integrate a small-bore dedicated mouse version of the scanner within a PET/CT platform.

18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters

International Nuclear Information System (INIS)

Mhlanga, Joyce C.; Lodge, Martin; Carrino, John A.; Wang, Hao; Wahl, Richard L.

2014-01-01

The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with 18 F-FDG. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological 18 F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73 ± 7.7 years). Six patients served as the control group (53.7 ± 9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r = 0.86. p = 0.007; r = 0.94, p = 0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7 ± 6.6 vs. 32.2 ± 0.4, p = 0.02; 37.5 ± 5.4 vs. 32.2 ± 0.4, p = 0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8 ± 4.2 vs. 18 ± 1.8, p = 0.13; 22.8 ± 5.38 vs. 20.1 ± 1.54, p= 0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9 ± 31.3 vs. 0, p = 0.03). Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted. (orig.)

Highly porous oil sorbent based on hollow fibers as the interceptor for oil on static and running water

Energy Technology Data Exchange (ETDEWEB)

Dong, Ting [College of Textiles, Donghua University, Shanghai 201620 (China); Cao, Shengbin [College of Textiles, Donghua University, Shanghai 201620 (China); School of Mechanical Engineering, Shanghai Dianji University, Shanghai 201306 (China); Xu, Guangbiao, E-mail: guangbiao_xu@dhu.edu.cn [College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science and Technology Ministry of Education, Donghua University, Shanghai 201620 (China)

2016-03-15

Highlights: • Highly porous sorbent was made up of kapok and PET fibers. • The sorbent was prepared by air-laying-bonding method. • The sorbent showed much higher oil sorption capacity than 100% loose kapok fibers. • The sorbent showed high intercepting efficiency to oils on water. • The runing of water significantly accelerated the oil leakage. - Abstract: Highly porous fibrous assembly made by kapok and hollow PET fibers was prepared by the air-laying-bonding method, and used as the interceptor for oils on static and running water. SEM showed that the vast majority of kapok and PET fibers in the assembly was intact and retained their hollow lumens, with the assembly's porosity high to 98.03%. Oil sorption tests exhibited that kapok/PET assembly could absorb 63.00 g/g of vegetable oil and 58.50 g/g of used motor oil, with high oil retention after 24 h dripping. In static condition of oil interception, the two oils started to leak at around 20 min for 10-mm thick kapok/PET wall. The time for that was prolonged with increasing the thickness of kapok/PET wall. After oil breakthrough, continuous oil leaking took place. The typical leakage was divided into three stages in which oils leaked separately in sharply increased rate, reduced rate and finally gently. In running condition, oils leaked in markedly quicker way than that in static condition, with initial leakage of oils shortened to less 6 min when the water ran at 60.35 ml/s. The leakage of oils was considerably accelerated with increasing running rates.

Highly porous oil sorbent based on hollow fibers as the interceptor for oil on static and running water

International Nuclear Information System (INIS)

Dong, Ting; Cao, Shengbin; Xu, Guangbiao

2016-01-01

Highlights: • Highly porous sorbent was made up of kapok and PET fibers. • The sorbent was prepared by air-laying-bonding method. • The sorbent showed much higher oil sorption capacity than 100% loose kapok fibers. • The sorbent showed high intercepting efficiency to oils on water. • The runing of water significantly accelerated the oil leakage. - Abstract: Highly porous fibrous assembly made by kapok and hollow PET fibers was prepared by the air-laying-bonding method, and used as the interceptor for oils on static and running water. SEM showed that the vast majority of kapok and PET fibers in the assembly was intact and retained their hollow lumens, with the assembly's porosity high to 98.03%. Oil sorption tests exhibited that kapok/PET assembly could absorb 63.00 g/g of vegetable oil and 58.50 g/g of used motor oil, with high oil retention after 24 h dripping. In static condition of oil interception, the two oils started to leak at around 20 min for 10-mm thick kapok/PET wall. The time for that was prolonged with increasing the thickness of kapok/PET wall. After oil breakthrough, continuous oil leaking took place. The typical leakage was divided into three stages in which oils leaked separately in sharply increased rate, reduced rate and finally gently. In running condition, oils leaked in markedly quicker way than that in static condition, with initial leakage of oils shortened to less 6 min when the water ran at 60.35 ml/s. The leakage of oils was considerably accelerated with increasing running rates.

Quantitative myocardial perfusion by O-15-water PET

DEFF Research Database (Denmark)

Thomassen, Anders; Petersen, Henrik; Johansen, Allan

2015-01-01

AIMS: Reporting of quantitative myocardial blood flow (MBF) is typically performed in standard coronary territories. However, coronary anatomy and myocardial vascular territories vary among individuals, and a coronary artery may erroneously be deemed stenosed or not if territorial demarcation...... disease (CAD). METHODS AND RESULTS: Forty-four patients with suspected CAD were included prospectively and underwent coronary CT-angiography and quantitative MBF assessment with O-15-water PET followed by invasive, quantitative coronary angiography, which served as reference. MBF was calculated...

Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

International Nuclear Information System (INIS)

Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Zdorovets, Maxim V.; Taltenov, Abzal A.

2015-01-01

In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H 2 O 2 under UV irradiation (H 2 O 2 /UV) and Fenton system under visible light (Fenton/H 2 O 2 /Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H 2 O 2 /UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H 2 O 2 /Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

Science.gov (United States)

Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Zdorovets, Maxim V.; Taltenov, Abzal A.

2015-12-01

In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H2O2 under UV irradiation (H2O2/UV) and Fenton system under visible light (Fenton/H2O2/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H2O2/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H2O2/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

High Resolution PET with 250 micrometer LSO Detectors and Adaptive Zoom

International Nuclear Information System (INIS)

Cherry, Simon R.; Qi, Jinyi

2012-01-01

There have been impressive improvements in the performance of small-animal positron emission tomography (PET) systems since their first development in the mid 1990s, both in terms of spatial resolution and sensitivity, which have directly contributed to the increasing adoption of this technology for a wide range of biomedical applications. Nonetheless, current systems still are largely dominated by the size of the scintillator elements used in the detector. Our research predicts that developing scintillator arrays with an element size of 250 (micro)m or smaller will lead to an image resolution of 500 (micro)m when using 18F- or 64Cu-labeled radiotracers, giving a factor of 4-8 improvement in volumetric resolution over the highest resolution research systems currently in existence. This proposal had two main objectives: (i) To develop and evaluate much higher resolution and efficiency scintillator arrays that can be used in the future as the basis for detectors in a small-animal PET scanner where the spatial resolution is dominated by decay and interaction physics rather than detector size. (ii) To optimize one such high resolution, high sensitivity detector and adaptively integrate it into the existing microPET II small animal PET scanner as a 'zoom-in' detector that provides higher spatial resolution and sensitivity in a limited region close to the detector face. The knowledge gained from this project will provide valuable information for building future PET systems with a complete ring of very high-resolution detector arrays and also lay the foundations for utilizing high-resolution detectors in combination with existing PET systems for localized high-resolution imaging.

{sup 18}F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters

Energy Technology Data Exchange (ETDEWEB)

Mhlanga, Joyce C.; Lodge, Martin [Johns Hopkins University School of Medicine, Division of Nuclear Medicine, The Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Carrino, John A. [Johns Hopkins University School of Medicine, Division of Musculoskeletal Radiology, The Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Wang, Hao [Johns Hopkins University School of Medicine, Department of Oncology Biostatistics Division, Baltimore, MD (United States); Wahl, Richard L. [Johns Hopkins University School of Medicine, Division of Nuclear Medicine, The Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Johns Hopkins University Hospitals, Division of Nuclear Medicine, Baltimore, MD (United States)

2014-12-15

The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with {sup 18}F-FDG. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological {sup 18}F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73 ± 7.7 years). Six patients served as the control group (53.7 ± 9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r = 0.86. p = 0.007; r = 0.94, p = 0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7 ± 6.6 vs. 32.2 ± 0.4, p = 0.02; 37.5 ± 5.4 vs. 32.2 ± 0.4, p = 0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8 ± 4.2 vs. 18 ± 1.8, p = 0.13; 22.8 ± 5.38 vs. 20.1 ± 1.54, p= 0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9 ± 31.3 vs. 0, p = 0.03). Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted. (orig.)

Field comparison of solar water disinfection (SODIS) efficacy between glass and polyethylene terephalate (PET) plastic bottles under sub-Saharan weather conditions.

Science.gov (United States)

Asiimwe, J K; Quilty, B; Muyanja, C K; McGuigan, K G

2013-12-01

Concerns about photodegradation products leaching from plastic bottle material into water during solar water disinfection (SODIS) are a major psychological barrier to increased uptake of SODIS. In this study, a comparison of SODIS efficacy using glass and plastic polyethylene terephalate (PET) bottles was carried out under strong real sunlight and overcast weather conditions at Makerere University in central Uganda. Both clear and turbid natural water samples from shallow wells and open dug wells, respectively, were used. Efficacy was determined from the inactivation of a wild strain of Escherichia coli in solar-exposed contaminated water in both glass and PET bottles. The studies reveal no significant difference in SODIS inactivation between glass and PET bottles (95% CI, p > 0.05), for all water samples under the different weather conditions except for clear water under overcast conditions where there was a small but significant difference (95% CI, p = 0.047) with less viable bacterial counts in PET bottles at two intermediate time points but not at the end of the exposure. The results demonstrate that SODIS efficacy in glass under tropical field conditions is comparable to PET plastic. SODIS users in these regions can choose either of reactors depending on availability and preference of the user.

Performance evaluation of a high resolution dedicated breast PET scanner

Energy Technology Data Exchange (ETDEWEB)

García Hernández, Trinitat, E-mail: mtrinitat@eresa.com; Vicedo González, Aurora; Brualla González, Luis; Granero Cabañero, Domingo [Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014 (Spain); Ferrer Rebolleda, Jose; Sánchez Jurado, Raúl; Puig Cozar Santiago, Maria del [Department of Nuclear Medicine, ERESA, Hospital General Universitario, Valencia 46014 (Spain); Roselló Ferrando, Joan [Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014 (Spain); Department of Physiology, University of Valencia, Valencia 46010 (Spain)

2016-05-15

Purpose: Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision). Methods: Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ({sup 18}F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared. Results: The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10. Conclusions: The DbPET has a good

Performance evaluation of a high resolution dedicated breast PET scanner

International Nuclear Information System (INIS)

García Hernández, Trinitat; Vicedo González, Aurora; Brualla González, Luis; Granero Cabañero, Domingo; Ferrer Rebolleda, Jose; Sánchez Jurado, Raúl; Puig Cozar Santiago, Maria del; Roselló Ferrando, Joan

2016-01-01

Purpose: Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision). Methods: Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ("1"8F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared. Results: The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10. Conclusions: The DbPET has a good performance

Calculation of left ventricular volumes and ejection fraction from dynamic cardiac-gated 15O-water PET/CT: 5D-PET

OpenAIRE

Jonny Nordström; Tanja Kero; Hendrik Johannes Harms; Charles Widström; Frank A. Flachskampf; Jens Sörensen; Mark Lubberink

2017-01-01

BACKGROUND: Quantitative measurement of myocardial blood flow (MBF) is of increasing interest in the clinical assessment of patients with suspected coronary artery disease (CAD). (15)O-water positron emission tomography (PET) is considered the gold standard for non-invasive MBF measurements. However, calculation of left ventricular (LV) volumes and ejection fraction (EF) is not possible from standard (15)O-water uptake images. The purpose of the present work was to investigate the possibility...

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

International Nuclear Information System (INIS)

Jeong, Ju Hye; Cho, Ihn Ho; Kong, Eun Jung; Chun, Kyung Ah

2014-01-01

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85±13 min after 18 F-FDG injection of 403± 45 MBq) and then (125±19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64± 0.70; in-phase, 1.29±1.01; opposed-phase, 1.29±1.15; water-weighted, 1.71±1.07; fat weighted, 0.56±1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63±1.62; SUVmax, 4.30±2.88) and contrast-enhanced PET

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ju Hye; Cho, Ihn Ho; Kong, Eun Jung; Chun, Kyung Ah [Yeungnam Univ. Hospital, Daegu (Korea, Republic of)

2014-03-15

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85±13 min after {sup 18}F-FDG injection of 403± 45 MBq) and then (125±19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64± 0.70; in-phase, 1.29±1.01; opposed-phase, 1.29±1.15; water-weighted, 1.71±1.07; fat weighted, 0.56±1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63±1.62; SUVmax, 4.30±2.88) and contrast

New horizons with PET/CT in high-tech radiotherapy planning

International Nuclear Information System (INIS)

Hadjieva, T.

2009-01-01

Full text:The precise delineation of exposed volumes in the high-tech radiotherapy is a major problem. The malignoma imaging was revolutionized by PET. PET became one of the routine imaging methods in developed countries in Europe and USA. PET with 18-FDG, combined with structural and topographic representation of images by CT, currently provides the most reliable information about the location and spread of tumor. Three dimensional radiotherapy planning is a challenge in today's practice and requires the most accurate visualization of the tumor, with its functional characteristics (proliferation activity, hypoxic cells, apoptosis, neoangiogenesis) and surrounding radiosensitive normal tissue and organs. The collected information about the main indications for radiotherapy planning using PET / CT in head and neck cancers , small cell lung carcinoma and some malignant lymphomas has been discussed. The problem of false positive and false negative findings has been also considered. The protocol for 18-FDG PET / CT conducting according to the agreed consensus of the IAEA expert meeting held in 2006 is presented

Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

Energy Technology Data Exchange (ETDEWEB)

Korolkov, Ilya V.; Mashentseva, Anastassiya A. [Institute of Nuclear Physics, Ibrahimov Str., 1, 050032 Almaty (Kazakhstan); The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan); Güven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey); Zdorovets, Maxim V. [Institute of Nuclear Physics, Ibrahimov Str., 1, 050032 Almaty (Kazakhstan); The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan); Taltenov, Abzal A. [The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan)

2015-12-15

In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H{sub 2}O{sub 2} under UV irradiation (H{sub 2}O{sub 2}/UV) and Fenton system under visible light (Fenton/H{sub 2}O{sub 2}/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H{sub 2}O{sub 2}/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H{sub 2}O{sub 2}/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

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

International Nuclear Information System (INIS)

Aide, Nicolas; Desmonts, Cedric; Agostini, Denis; Bardet, Stephane; Bouvard, Gerard; Beauregard, Jean-Mathieu; Roselt, Peter; Neels, Oliver; Beyer, Thomas; Kinross, Kathryn; Hicks, Rodney J.

2010-01-01

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 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 air and SOR water were 5.3 and 7.5%, respectively. A strong correlation (r 2 = 0.97, p 2 = 0.98; slope = 0.89, p 2 = 0.96; slope = 0.62, p 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.)

High-resolution multi-slice PET

International Nuclear Information System (INIS)

Yasillo, N.J.; Chintu Chen; Ordonez, C.E.; Kapp, O.H.; Sosnowski, J.; Beck, R.N.

1992-01-01

This report evaluates the progress to test the feasibility and to initiate the design of a high resolution multi-slice PET system. The following specific areas were evaluated: detector development and testing; electronics configuration and design; mechanical design; and system simulation. The design and construction of a multiple-slice, high-resolution positron tomograph will provide substantial improvements in the accuracy and reproducibility of measurements of the distribution of activity concentrations in the brain. The range of functional brain research and our understanding of local brain function will be greatly extended when the development of this instrumentation is completed

PET/CT in staging of the high risk prostate cancer

International Nuclear Information System (INIS)

Bergero, M.A.; David, C.; Dipatto, F.; Popeneciu, V.; Ríos, L.; Faccio, F.

2016-01-01

Objectives: In the last decade multimodal management of the high risk prostate cancer (HRPC) is a therapeutic option in selected patients and the staging of these patients depends on the current diagnostic methods (DM) which have low diagnostic accuracy for detecting metastasis (MTS). The positron emission tomography/computed tomography (PET/CT) would have a greater diagnostic accuracy and it is presented as a better DM for staging prostate cancer (PC). The aim of this article is present 2 patients in whom PET/CT modified the therapeutic decision and conduct a literature review. Materials and methods: 2 patients with HRPC who performed PET/CT and it modified the therapeutic behavior were described and a systematic review of the literature was conducted using PubMed, Embase, SciELO and Cochrane answering the question: has PET/CT a place in HRPC staging? Results: TPET/CT has a sensitivity and specificity between 19% to 100% and 67% to 98,5 %, respectively, in assessing nodal involvement by PC and between 84% to 96% and 92.3% to 100%, respectively, in assessing bone involvement by PC. Besides PET/CT allowed to modify the therapeutic behavior between 20% to 40% of the patients with PC. Conclusions: PET/CT has good specificity and moderate sensitivity for detecting lymph node MTS and good sensitivity and specificity for detecting bone MTS. Besides PET/CT modified the therapeutic behavior in 1/3 of cases and it allowed us to modify the therapeutic behavior in our series. (authors) [es

Mechanical Characterization and Water Absorption Behaviour of Interwoven Kenaf/PET Fibre Reinforced Epoxy Hybrid Composite

Directory of Open Access Journals (Sweden)

Yakubu Dan-mallam

2015-01-01

Full Text Available The development of interwoven fabric for composite production is a novel approach that can be adopted to address the challenges of balanced mechanical properties and water absorption behaviour of polymer composites. In this paper, kenaf and PET (polyethylene terephthalate fibre were selected as reinforcing materials to develop the woven fabric, and low viscosity epoxy resin was chosen as the matrix. Vacuum infusion process was adopted to produce the hybrid composite due to its superior advantages over hand lay-up technique. The weight percentage composition of the Epoxy/kenaf/PET hybrid composite was maintained at 70/15/15 and 60/20/20, respectively. A significant increase in tensile strength and elastic modulus of approximately 73% and 53% was recorded in relation to neat epoxy. Similarly, a substantial increase in flexural, impact, and interlaminar properties was also realized in relation to neat epoxy. This enhancement in mechanical properties may be attributed to the interlocking structure of the interwoven fabric, individual properties of kenaf and PET fibres, strong interfacial bonding, and resistance of the fibres to impact loading. The water absorption of the composites was studied by prolonged exposure in distilled water, and the moisture absorption pattern was found to follow Fickian behaviour.

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

In-beam PET at high-energy photon beams: a feasibility study

Science.gov (United States)

Müller, H.; Enghardt, W.

2006-04-01

For radiation therapy with carbon ion beams, either for the stable isotope 12C or for the radioactive one 11C, it has been demonstrated that the β+-activity distribution created or deposited, respectively, within the irradiated volume can be visualized by means of positron emission tomography (PET). The PET images provide valuable information for quality assurance and precision improvement of ion therapy. Dedicated PET scanners have been integrated into treatment sites at the Heavy Ion Medical Accelerator at Chiba (HIMAC), Japan, and the Gesellschaft für Schwerionenforschung (GSI), Germany, to make PET imaging feasible during therapeutic irradiation (in-beam PET). A similar technique may be worthwhile for radiotherapy with high-energy bremsstrahlung. In addition to monitoring the dose delivery process which in-beam PET has been primarily developed for, it may be expected that radiation response of tissue can be detected by means of in-beam PET. We investigate the applicability of PET for treatment control in the case of using bremsstrahlung spectra produced by 15-50 MeV electrons. Target volume activation due to (γ, n) reactions at energies above 20 MeV yields moderate β+-activity levels, which can be employed for imaging. The radiation from positrons produced by pair production is not presently usable because the detectors are overloaded due to the low duty factor of medical electron linear accelerators. However, the degradation of images caused by positron motion between creation and annihilation seems to be tolerable.

High-performance electronics for time-of-flight PET systems

International Nuclear Information System (INIS)

Choong, W-S; Peng, Q; Vu, C Q; Turko, B T; Moses, W W

2013-01-01

We have designed and built a high-performance readout electronics system for time-of-flight positron emission tomography (TOF PET) cameras. The electronics architecture is based on the electronics for a commercial whole-body PET camera (Siemens/CPS Cardinal electronics), modified to improve the timing performance. The fundamental contributions in the electronics that can limit the timing resolution include the constant fraction discriminator (CFD), which converts the analog electrical signal from the photo-detector to a digital signal whose leading edge is time-correlated with the input signal, and the time-to-digital converter (TDC), which provides a time stamp for the CFD output. Coincident events are identified by digitally comparing the values of the time stamps. In the Cardinal electronics, the front-end processing electronics are performed by an Analog subsection board, which has two application-specific integrated circuits (ASICs), each servicing a PET block detector module. The ASIC has a built-in CFD and TDC. We found that a significant degradation in the timing resolution comes from the ASIC's CFD and TDC. Therefore, we have designed and built an improved Analog subsection board that replaces the ASIC's CFD and TDC with a high-performance CFD (made with discrete components) and TDC (using the CERN high-performance TDC ASIC). The improved Analog subsection board is used in a custom single-ring LSO-based TOF PET camera. The electronics system achieves a timing resolution of 60 ps FWHM. Prototype TOF detector modules are read out with the electronics system and give coincidence timing resolutions of 259 ps FWHM and 156 ps FWHM for detector modules coupled to LSO and LaBr 3 crystals respectively.

Self-consolidating concretes containing waste PET bottles as sand replacement

Science.gov (United States)

Khalid, Faisal Sheikh; Azmi, Nurul Bazilah; Mazenan, Puteri Natasya; Shahidan, Shahiron; Othman, Nor hazurina; Guntor, Nickholas Anting Anak

2018-02-01

This study evaluates the effect of self-consolidating concrete (SCC) containing waste polyethylene terephthalate (PET) granules on the fresh, mechanical and water absorption properties. Fine aggregates were replaced from 0% to 8% by PET granules. The fresh properties of SCC containing PET granules were determined using slump flow and V-funnel flow time tests. The compressive and splitting tensile strength were evaluated. The results indicated that utilization of waste PET granules in production of SCC could be an effective way for recycling purpose. The maximum amount of PET replacement should be limited to 5%. Exceeding 5% of PET content may result in an increase of V-funnel flow time to overpass the limiting value, decrease in strength. The production of high performance SCC containing 5% PET granules satisfies all the requirements for SCC with satisfactory outputs.

Do carotid MR surface coils affect PET quantification in PET/MR imaging?

International Nuclear Information System (INIS)

Willemink, Martin J; Eldib, Mootaz; Leiner, Tim; Fayad, Zahi A; Mani, Venkatesh

2015-01-01

To evaluate the effect of surface coils for carotid MR imaging on PET quantification in a clinical simultaneous whole-body PET/MR scanner. A cylindrical phantom was filled with a homogeneous 2L water-FDG mixture at a starting dose of 301.2MBq. Clinical PET/MR and PET/CT systems were used to acquire PET-data without a coil (reference standard) and with two carotid MRI coils (Siemens Special Purpose 8-Channel and Machnet 4-Channel Phased Array). PET-signal attenuation was evaluated with Osirix using 51 (PET/MR) and 37 (PET/CT) circular ROIs. Mean and maximum standardized uptake values (SUVs) were quantified for each ROI. Furthermore, SUVs of PET/MR and PET/CT were compared. For validation, a patient was scanned with an injected dose of 407.7MBq on both a PET/CT and a PET/MR system without a coil and with both coils. PET/MR underestimations were -2.2% (Siemens) and -7.8% (Machnet) for SUVmean, and -1.2% (Siemens) and -3.3% (Machnet) for SUVmax, respectively. For PET/CT, underestimations were -1.3% (Siemens) and -1.4% (Machnet) for SUVmean and -0.5% (both Siemens and Machnet) for SUVmax, respectively using no coil data as reference. Except for PET/CT SUVmax values all differences were significant. SUVs differed significantly between PET/MR and PET/CT with SUVmean values of 0.51-0.55 for PET/MR and 0.68-0.69 for PET/CT, respectively. The patient examination showed that median SUVmean values measured in the carotid arteries decreased from 0.97 without a coil to 0.96 (Siemens) and 0.88 (Machnet). Carotid surface coils do affect attenuation correction in both PET/MR and PET/CT imaging. Furthermore, SUVs differed significantly between PET/MR and PET/CT.

High Dose MicroCT Does Not Contribute Toward Improved MicroPET/CT Image Quantitative Accuracy and Can Limit Longitudinal Scanning of Small Animals

Directory of Open Access Journals (Sweden)

Wendy A. McDougald

2017-10-01

Full Text Available Obtaining accurate quantitative measurements in preclinical Positron Emission Tomography/Computed Tomography (PET/CT imaging is of paramount importance in biomedical research and helps supporting efficient translation of preclinical results to the clinic. The purpose of this study was two-fold: (1 to investigate the effects of different CT acquisition protocols on PET/CT image quality and data quantification; and (2 to evaluate the absorbed dose associated with varying CT parameters.Methods: An air/water quality control CT phantom, tissue equivalent material phantom, an in-house 3D printed phantom and an image quality PET/CT phantom were imaged using a Mediso nanoPET/CT scanner. Collected data was analyzed using PMOD software, VivoQuant software and National Electric Manufactures Association (NEMA software implemented by Mediso. Measured Hounsfield Unit (HU in collected CT images were compared to the known HU values and image noise was quantified. PET recovery coefficients (RC, uniformity and quantitative bias were also measured.Results: Only less than 2 and 1% of CT acquisition protocols yielded water HU values < −80 and air HU values < −840, respectively. Four out of 11 CT protocols resulted in more than 100 mGy absorbed dose. Different CT protocols did not impact PET uniformity and RC, and resulted in <4% overall bias relative to expected radioactive concentration.Conclusion: Preclinical CT protocols with increased exposure times can result in high absorbed doses to the small animals. These should be avoided, as they do not contributed toward improved microPET/CT image quantitative accuracy and could limit longitudinal scanning of small animals.

A useful PET probe [11C]BU99008 with ultra-high specific radioactivity for small animal PET imaging of I2-imidazoline receptors in the hypothalamus

International Nuclear Information System (INIS)

Kawamura, Kazunori; Shimoda, Yoko; Yui, Joji; Zhang, Yiding; Yamasaki, Tomoteru; Wakizaka, Hidekatsu; Hatori, Akiko; Xie, Lin; Kumata, Katsushi; Fujinaga, Masayuki; Ogawa, Masanao; Kurihara, Yusuke; Nengaki, Nobuki; Zhang, Ming-Rong

2017-01-01

Introduction: A positron emission tomography (PET) probe with ultra-high specific radioactivity (SA) enables measuring high receptor specific binding in brain regions by avoiding mass effect of the PET probe itself. It has been reported that PET probe with ultra-high SA can detect small change caused by endogenous or exogenous ligand. Recently, Kealey et al. developed [ 11 C]BU99008, a more potent PET probe for I 2 -imidazoline receptors (I 2 Rs) imaging, with a conventional SA (mean 76 GBq/μmol) showed higher specific binding in the brain. Here, to detect small change of specific binding for I 2 Rs caused by endogenous or exogenous ligand in an extremely small region, such as hypothalamus in the brain, we synthesized and evaluated [ 11 C]BU99008 with ultra-high SA as a useful PET probe for small-animal PET imaging of I 2 Rs. Methods: [ 11 C]BU99008 was prepared by [ 11 C]methylation of N-desmethyl precursor with [ 11 C]methyl iodide. Biodistribution, metabolite analysis, and brain PET studies were conducted in rats. Results: [ 11 C]BU99008 with ultra-high SA in the range of 5400–16,600 GBq/μmol were successfully synthesized (n = 7), and had appropriate radioactivity for in vivo study. In the biodistribution study, the mean radioactivity levels in all investigated tissues except for the kidney did not show significant difference between [ 11 C]BU99008 with ultra-high SA and that with conventional SA. In the metabolite analysis, the percentage of unchanged [ 11 C]BU99008 at 30 min after the injection of probes with ultra-high and conventional SA was similar in rat brain and plasma. In the PET study of rats' brain, radioactivity level (AUC 30–60 min ) in the hypothalamus of rats injected with [ 11 C]BU99008 with ultra-high SA (64 [SUV ∙ min]) was significantly higher than that observed for that with conventional SA (50 [SUV ∙ min]). The specific binding of [ 11 C]BU99008 with ultra-high SA (86% of total binding) for I 2 R was higher than that of

Effect of temperature on the release of intentionally and non-intentionally added substances from polyethylene terephthalate (PET) bottles into water: chemical analysis and potential toxicity.

Science.gov (United States)

Bach, Cristina; Dauchy, Xavier; Severin, Isabelle; Munoz, Jean-François; Etienne, Serge; Chagnon, Marie-Christine

2013-08-15

The purpose of this study was to investigate the impact of temperature on the release of PET-bottle constituents into water and to assess the potential health hazard using in vitro bioassays with bacteria and human cell lines. Aldehydes, trace metals and other compounds found in plastic packaging were analysed in PET-bottled water stored at different temperatures: 40, 50, and 60°C. In this study, temperature and the presence of CO2 increased the release of formaldehyde, acetaldehyde and antimony (Sb). In parallel, genotoxicity assays (Ames and micronucleus assays) and transcriptional-reporter gene assays for estrogenic and anti-androgenic activity were performed on bottled water extracts at relevant consumer exposure levels. As expected, and in accordance with the chemical formulations specified for PET bottles, neither phthalates nor UV stabilisers were present in the water extracts. However, 2,4-di-tert-butylphenol, a degradation compound of phenolic antioxidants, was detected. In addition, an intermediary monomer, bis(2-hydroxyethyl)terephthalate, was found but only in PET-bottled waters. None of the compounds are on the positive list of EU Regulation No. 10/2011. However, the PET-bottled water extracts did not induce any cytotoxic, genotoxic or endocrine-disruption activity in the bioassays after exposure. Copyright © 2013 Elsevier Ltd. All rights reserved.

PetIGA-MF: a multi-field high-performance toolbox for structure-preserving B-splines spaces

KAUST Repository

Sarmiento, Adel; Cô rtes, A.M.A.; Garcia, D.A.; Dalcin, Lisandro; Collier, N.; Calo, V.M.

2016-01-01

We describe a high-performance solution framework for isogeometric discrete differential forms based on B-splines: PetIGA-MF. Built on top of PetIGA, an open-source library we have built and developed over the last decade, PetIGA-MF is a general

Quantification of renal cortical blood flow using factor analysis of O-15 water dynamic PET images

International Nuclear Information System (INIS)

Seo, Kang Jun; Ahn, Ji Young; Lee, Jae Sung; Paeng, Jin Chul; Cheon, Gi Jeong; Lee, Dong Soo; Noh, Tae Won; Chung, June Key; Lee, Myung Chul

2000-01-01

To obtain spatial distribution of renal factor images, input function, and regional tissue time-activity curve (TAC) from O-15 water dynamic PET images non-invasively, factor analysis (FA) was used. O-15 water dynamic PET scans were performed on 3 normal dogs (22 ∼ 29 kg) with the bolus injection of O-15 water (555 ∼ 740 Mbq). We performed FA on the masked dynamic images and obtained the pure TACs and the corresponding factor images. Microsphere experiment also was performed. 37MBq of microsphere labeled with Sc-46 was injected into the left ventricle. Arterial input functions derived from the PET images using FA were compared with the invasively derived arterial blood samples. The renal cortical blood flow using the TACs by FA was within the normal range of 1.23 ∼ 2.46 ml/min/g. In microsphere study, the renal cortical blood flow of left kidney by FA was 2.49±0.47 ml/min/g (1.81∼2.90 ml/min/g) and by microsphere was 2.52 ±0.19 ml/min/g (2.34 ∼2.68 ml/min/g). In right kidney, flow by FA was 2.02 ±0.32 ml/min/g (1.82∼2.49 ml/min/g) and by microsphere was 2.49 ±0.27 ml/min/g (2.02∼2.7). FA is a useful and robust method to extract input functions and tissue TACs from O-15 dynamic renal PET. Renal cortical blood flow can be estimated non-invasively using FA and it will be helpful for the assessment of renal functional disease

A new PET detector concept for compact preclinical high-resolution hybrid MR-PET

Science.gov (United States)

Berneking, Arne; Gola, Alberto; Ferri, Alessandro; Finster, Felix; Rucatti, Daniele; Paternoster, Giovanni; Jon Shah, N.; Piemonte, Claudio; Lerche, Christoph

2018-04-01

This work presents a new PET detector concept for compact preclinical hybrid MR-PET. The detector concept is based on Linearly-Graded SiPM produced with current FBK RGB-HD technology. One 7.75 mm x 7.75 mm large sensor chip is coupled with optical grease to a black coated 8 mm x 8 mm large and 3 mm thick monolithic LYSO crystal. The readout is obtained from four readout channels with the linear encoding based on integrated resistors and the Center of Gravity approach. To characterize the new detector concept, the spatial and energy resolutions were measured. Therefore, the measurement setup was prepared to radiate a collimated beam to 25 different points perpendicular to the monolithic scintillator crystal. Starting in the center point of the crystal at 0 mm / 0 mm and sampling a grid with a pitch of 1.75 mm, all significant points of the detector were covered by the collimator beam. The measured intrinsic spatial resolution (FWHM) was 0.74 +/- 0.01 mm in x- and 0.69 +/- 0.01 mm in the y-direction at the center of the detector. At the same point, the measured energy resolution (FWHM) was 13.01 +/- 0.05 %. The mean intrinsic spatial resolution (FWHM) over the whole detector was 0.80 +/- 0.28 mm in x- and 0.72 +/- 0.19 mm in y-direction. The energy resolution (FWHM) of the detector was between 13 and 17.3 % with an average energy resolution of 15.7 +/- 1.0 %. Due to the reduced thickness, the sensitivity of this gamma detector is low but still higher than pixelated designs with the same thickness due to the monolithic crystals. Combining compact design, high spatial resolution, and high sensitivity, the detector concept is particularly suitable for applications where the scanner bore size is limited and high resolution is required - as is the case in small animal hybrid MR-PET.

Acetaldehyde in mineral water stored in polyethylene terephthalate (PET) bottles: Odour threshold and quantification

NARCIS (Netherlands)

Nijssen, B.; Kamperman, T.; Jetten, J.

1996-01-01

The use of PET bottles for packaging soft drinks and mineral waters is still growing world wide. The production process for these bottles is improving constantly. These improvements are focussed on bottles with better barrier properties, higher inertness and higher heat stability. One of the factors

Blood perfusion in osteomyelitis studied with [15O]water PET in a juvenile porcine model

DEFF Research Database (Denmark)

Jødal, Lars; Nielsen, Ole L; Afzelius, Pia

2017-01-01

and not quantitative. Quantitative assessment of perfusion could aid in the selection of therapy. A non-invasive, quantitative way to study perfusion is dynamic [15O]water positron emission tomography (PET). We aim to demonstrate that the method can be used for measuring perfusion in OM lesions and hypothesize...... that perfusion will be less elevated in OM lesions than in soft tissue (ST) infection. The study comprised 11 juvenile pigs with haematogenous osteomyelitis induced by injection of Staphylococcus aureus into the right femoral artery 1 week before scanning (in one pig, 2 weeks). The pigs were dynamically PET...

New DOI identification approach for high-resolution PET detectors

International Nuclear Information System (INIS)

Choghadi, Amin; Takahashi, Hiroyuki; Shimazoe, Kenji

2016-01-01

Depth-of-interaction (DOI) Identification in positron emission tomography (PET) detectors is getting importance as it improves spatial resolution in both conventional and time-of-flight (TOF) PET, and coincidence time resolution (CTR) in TOF-PET. In both prototypes, spatial resolution is affected by parallax error caused by length of scintillator crystals. This long length also contributes substantial timing uncertainty to the time resolution of TOF-PET. Through DOI identification, both parallax error and the timing uncertainty caused by the length of crystal can be resolved. In this work, a novel approach to estimate DOI was investigated, enjoying the interference of absorbance spectrum of scintillator crystals with their emission spectrum. Because the absorption length is close to zero for shorter wavelengths of crystal emission spectrum, the counts in this range of spectrum highly depend on DOI; that is, higher counts corresponds to deeper interactions. The ratio of counts in this range to the total counts is a good measure to estimate DOI. In order to extract such ratio, two photodetectors for each crystal are used and an optical filter is mounted only on top of one of them. The ratio of filtered output to non-filtered output can be utilized as DOI estimator. For a 2×2×20 mm 3 GAGG:Ce scintillator, 8-mm DOI resolution achieved in our simulations. (author)

A Case of Esophageal Leiomyoma Showing High FDG Uptake on F-18 FDG PET

Energy Technology Data Exchange (ETDEWEB)

Lee, Jai Hyuen [College of Medicine, Cheonan (Korea, Republic of); Ryu, Jin Sook [Asan Medical Center, University of Ulsan College of Medicine (Korea, Republic of)

2008-08-15

An esophageal leiomyoma is the most common benign tumor of the esophagus mainly occurred in intramural portion. Occasionally, it is difficult to discriminate esophageal malignancy from large leiomyoma. Although F-18 FDG PET has been used for differentiating malignant from benign disease, false-positive cases have been reported. Recently, uterine leiomyoma has been reported to have relatively high F-18 FDG uptake in some patients but little is known about how an esophageal leiomyoma might be showed on F-18 FDG PET. We report a case of esophageal leiomyoma that showed high FDG uptake on PET images.

A Case of Esophageal Leiomyoma Showing High FDG Uptake on F-18 FDG PET

International Nuclear Information System (INIS)

Lee, Jai Hyuen; Ryu, Jin Sook

2008-01-01

An esophageal leiomyoma is the most common benign tumor of the esophagus mainly occurred in intramural portion. Occasionally, it is difficult to discriminate esophageal malignancy from large leiomyoma. Although F-18 FDG PET has been used for differentiating malignant from benign disease, false-positive cases have been reported. Recently, uterine leiomyoma has been reported to have relatively high F-18 FDG uptake in some patients but little is known about how an esophageal leiomyoma might be showed on F-18 FDG PET. We report a case of esophageal leiomyoma that showed high FDG uptake on PET images

An experimental phantom study of the effect of gadolinium-based MR contrast agents on PET attenuation coefficients and PET quantification in PET-MR imaging: application to cardiac studies.

Science.gov (United States)

O' Doherty, Jim; Schleyer, Paul

2017-12-01

Simultaneous cardiac perfusion studies are an increasing trend in PET-MR imaging. During dynamic PET imaging, the introduction of gadolinium-based MR contrast agents (GBCA) at high concentrations during a dual injection of GBCA and PET radiotracer may cause increased attenuation effects of the PET signal, and thus errors in quantification of PET images. We thus aimed to calculate the change in linear attenuation coefficient (LAC) of a mixture of PET radiotracer and increasing concentrations of GBCA in solution and furthermore, to investigate if this change in LAC produced a measurable effect on the image-based PET activity concentration when attenuation corrected by three different AC strategies. We performed simultaneous PET-MR imaging of a phantom in a static scenario using a fixed activity of 40 MBq [18 F]-NaF, water, and an increasing GBCA concentration from 0 to 66 mM (based on an assumed maximum possible concentration of GBCA in the left ventricle in a clinical study). This simulated a range of clinical concentrations of GBCA. We investigated two methods to calculate the LAC of the solution mixture at 511 keV: (1) a mathematical mixture rule and (2) CT imaging of each concentration step and subsequent conversion to LAC at 511 keV. This comparison showed that the ranges of LAC produced by both methods are equivalent with an increase in LAC of the mixed solution of approximately 2% over the range of 0-66 mM. We then employed three different attenuation correction methods to the PET data: (1) each PET scan at a specific millimolar concentration of GBCA corrected by its corresponding CT scan, (2) each PET scan corrected by a CT scan with no GBCA present (i.e., at 0 mM GBCA), and (3) a manually generated attenuation map, whereby all CT voxels in the phantom at 0 mM were replaced by LAC = 0.1 cm -1 . All attenuation correction methods (1-3) were accurate to the true measured activity concentration within 5%, and there were no trends in image

Combined 18F-Fluciclovine PET/MRI Shows Potential for Detection and Characterization of High-Risk Prostate Cancer.

Science.gov (United States)

Elschot, Mattijs; Selnæs, Kirsten M; Sandsmark, Elise; Krüger-Stokke, Brage; Størkersen, Øystein; Giskeødegård, Guro F; Tessem, May-Britt; Moestue, Siver A; Bertilsson, Helena; Bathen, Tone F

2018-05-01

The objective of this study was to investigate whether quantitative imaging features derived from combined 18 F-fluciclovine PET/multiparametric MRI show potential for detection and characterization of primary prostate cancer. Methods: Twenty-eight patients diagnosed with high-risk prostate cancer underwent simultaneous 18 F-fluciclovine PET/MRI before radical prostatectomy. Volumes of interest (VOIs) for prostate tumors, benign prostatic hyperplasia (BPH) nodules, prostatitis, and healthy tissue were delineated on T2-weighted images, using histology as a reference. Tumor VOIs were marked as high-grade (≥Gleason grade group 3) or not. MRI and PET features were extracted on the voxel and VOI levels. Partial least-squared discriminant analysis (PLS-DA) with double leave-one-patient-out cross-validation was performed to distinguish tumors from benign tissue (BPH, prostatitis, or healthy tissue) and high-grade tumors from other tissue (low-grade tumors or benign tissue). The performance levels of PET, MRI, and combined PET/MRI features were compared using the area under the receiver-operating-characteristic curve (AUC). Results: Voxel and VOI features were extracted from 40 tumor VOIs (26 high-grade), 36 BPH VOIs, 6 prostatitis VOIs, and 37 healthy-tissue VOIs. PET/MRI performed better than MRI and PET alone for distinguishing tumors from benign tissue (AUCs of 87%, 81%, and 83%, respectively, at the voxel level and 96%, 93%, and 93%, respectively, at the VOI level) and high-grade tumors from other tissue (AUCs of 85%, 79%, and 81%, respectively, at the voxel level and 93%, 93%, and 91%, respectively, at the VOI level). T2-weighted MRI, diffusion-weighted MRI, and PET features were the most important for classification. Conclusion: Combined 18 F-fluciclovine PET/multiparametric MRI shows potential for improving detection and characterization of high-risk prostate cancer, in comparison to MRI and PET alone. © 2018 by the Society of Nuclear Medicine and Molecular

Clinical Application of F-18 FDG PET (PET/CT) in Malignancy of Unknown Origin

International Nuclear Information System (INIS)

Kim, Byung Il

2008-01-01

Diagnosis of primary origin site in the management of malignancy of unknown origin (MUO) is the most important issue. According to the histopathologic subtype of primary lesion, specialized treatment can be given and survival gain is expected. F-18 FDG PET (PET/CT) has been estimated as useful in detection of primary lesion with high sensitivity and moderate specificity. F-18 FDG PET (PET/CT) study before conventional studies is also recommended because it has high diagnostic performance compared to conventional studies. Although there has few data, F-18 FDG PET (PET/CT) is expected to be useful in diagnosis of recurrence, restaging, evaluation of treatment effect, considering that PET (PET/CT) has been reported as useful in other malignancies

Composites based on PET and red mud residues as catalyst for organic removal from water

Energy Technology Data Exchange (ETDEWEB)

Bento, Natálya I.; Santos, Patrícia S.C. [Science and Technology Institute, Federal University of Alfenas, Rodovia José Aurélio Vilela, 11999, BR 267, Km 533, CEP 37715-400 Poços de Caldas, MG (Brazil); Souza, Talita E. de; Oliveira, Luiz C.A. [Department of Chemistry, Federal University of Minas Gerais, UFMG, Av. Antônio Carlos, 6627, Pampulha, 31270-901 Belo Horizonte, MG (Brazil); Castro, Cínthia S., E-mail: cinthia.soares.castro@gmail.com [Science and Technology Institute, Federal University of Alfenas, Rodovia José Aurélio Vilela, 11999, BR 267, Km 533, CEP 37715-400 Poços de Caldas, MG (Brazil)

2016-08-15

Highlights: • Composite based on carbon/iron oxide from PET and red mud wastes for organic contaminants oxidation. • Composites are mainly composed of hematite and a carbon matrix from PET decomposition. • RM/PET-15 presents the highest methylene blue (MB) removal from water, by combined adsorption and oxidation processes. • The dye oxidation was confirmed by ESI-MS studies. • The RM/PET catalysts can be reused for at least four batch runs. - Abstract: In this study, we obtained a composite based on carbon/iron oxide from red mud and PET (poly(ethylene terephthalate)) wastes by mechanical mixture (10, 15 and 20 wt.% of PET powder/red mud) followed by a controlled thermal treatment at 400 °C under air. XRD analyses revealed that the α-Fe{sub 2}O{sub 3} is the main phase formed from red mud. TPR analyses showed that the iron oxide present in the composites undergoes reduction at lower temperature to form Fe{sup 2+} species present in Fe{sub 3}O{sub 4}, indicating that the iron oxide in the composite can exhibit greater reactivity in the catalytic processes compared to the original red mud. In fact, catalytic tests showed that the composites presented higher capacity to remove methylene blue dye (MB), presenting about 90% of removal after 24 h of reaction. The MB removal was also monitored by mass spectrometer with ionization via electrospray (ESI-MS), which demonstrated the occurrence of the oxidation process, showing the formation of MB oxidation products. The stability of the composites was confirmed after four reuse cycles. The results seem to indicate that PET carbon deposited over the iron oxide from red mud promotes adsorption of the contaminant allowing its contact with the iron atoms and their consequent reaction.

Clinical Application of F-18 FDG PET (PET/CT) in Colo-rectal and Anal Cancer

International Nuclear Information System (INIS)

Kim, Byung Il

2008-01-01

In the management of colo-retal and anal cancer, accurate staging, treatment evaluation, early detection of recurrence are main clinical problems. F-18 FDG PET (PET/CT) has been reported as useful in the management of colo-rectal and anal cancer because that PET has high diagnostic performance comparing to conventional studies. In case of liver metastases, for confirmation of no extrahepatic metastases, in case of high risk of metastasis, for avoiding unnecessary operation, PET (PET/CT) is expected more useful. In anal cancer, PET is expected useful in lymph node staging. For the early prediction of chemotherapy or radiation therapy effect PET has been reported as useful, also. In early detection of recurrence by PET, cost-benefit advantages has been suggested, also. PET/CT is expected to have higher diagnostic performance than PET alone

F-FDG PET/CT (PET/CT) influences management in patients with known or suspected pancreatic cancer

International Nuclear Information System (INIS)

Barber, Thomas W.; Kalff, Victor; Cherk, Martin H.; Yap, Kenneth SK.; Evans, Peter; Kelly, Michael J.

2009-01-01

Full text: Objective: To assess the impact on clinical management of PET/CT in patients with known or suspected pancreatic cancer. Methods: Between April 2006 and September 2008,25 PET/CT scans were performed using a dedicated PET/CT (22 scans) or a coincidence hybrid PET/CT camera (3 scans) in 23 patients with known or suspected pancreatic cancer. 17 scans were performed for initial evaluation and 8 for restaging of disease. The pre-PET/CT management plan and for intent were prospectively recorded in all cases. The post-PET/CT management plan was determined from the medical record and for discussions with treating clinicians. The impact of PET/CT on management was classified as High, Medium, Low or None, defined using ANZAPNM PET data collection project criteria. Follow-up was used to reconcile any discordance between PET/CT and conventional imaging. Results: Overall, PET/CT management impact was classified as high (n equal 7), medium (n equal 4), low (n equal 10) or none (n equal 4). Impact was either high or medium in l l/25 patients (44%) (95% confidence interval; 24 - 64%). Impact was high in 4/17 patients imaged for initial evaluation, predominantly by clarifying equivocal lesions on conventional imaging. In restaged patients, PET/CT impact was high in 3/8, and it correctly modified disease extent in 5/8. In the 16 discordant studies, PET/CT assessment was correct in 10, conventional imaging in 4 and there was insufficient information in 2. Conclusion: PET/CT has high or medium management impact in 44% of patients imaged for known or suspected pancreatic cancer, more commonly during restaging. Discordant PET/CT results were usually correct.

Comparison of Imaging Characteristics of 124I PET for Determination of Optimal Energy Window on the Siemens Inveon PET

Directory of Open Access Journals (Sweden)

A Ram Yu

2016-01-01

Full Text Available Purpose.124I has a half-life of 4.2 days, which makes it suitable for imaging over several days over its uptake and washout phases. However, it has a low positron branching ratio (23%, because of prompt gamma coincidence due to high-energy γ-photons (602 to 1,691 keV, which are emitted in cascade with positrons. Methods. In this study, we investigated the optimal PET energy window for 124I PET based on image characteristics of reconstructed PET. Image characteristics such as nonuniformities, recovery coefficients (RCs, and the spillover ratios (SORs of 124I were measured as described in NEMA NU 4-2008 standards. Results. The maximum and minimum prompt gamma coincidence fraction (PGF were 33% and 2% in 350~800 and 400~590 keV, respectively. The difference between best and worst uniformity in the various energy windows was less than 1%. The lowest SORs of 124I were obtained at 350~750 keV in nonradioactive water compartment. Conclusion. Optimal energy window should be determined based on image characteristics. Our developed correction method would be useful for the correction of high-energy prompt gamma photon in 124I PET. In terms of the image quality of 124I PET, our findings indicate that an energy window of 350~750 keV would be optimal.

3D conditional generative adversarial networks for high-quality PET image estimation at low dose.

Science.gov (United States)

Wang, Yan; Yu, Biting; Wang, Lei; Zu, Chen; Lalush, David S; Lin, Weili; Wu, Xi; Zhou, Jiliu; Shen, Dinggang; Zhou, Luping

2018-07-01

Positron emission tomography (PET) is a widely used imaging modality, providing insight into both the biochemical and physiological processes of human body. Usually, a full dose radioactive tracer is required to obtain high-quality PET images for clinical needs. This inevitably raises concerns about potential health hazards. On the other hand, dose reduction may cause the increased noise in the reconstructed PET images, which impacts the image quality to a certain extent. In this paper, in order to reduce the radiation exposure while maintaining the high quality of PET images, we propose a novel method based on 3D conditional generative adversarial networks (3D c-GANs) to estimate the high-quality full-dose PET images from low-dose ones. Generative adversarial networks (GANs) include a generator network and a discriminator network which are trained simultaneously with the goal of one beating the other. Similar to GANs, in the proposed 3D c-GANs, we condition the model on an input low-dose PET image and generate a corresponding output full-dose PET image. Specifically, to render the same underlying information between the low-dose and full-dose PET images, a 3D U-net-like deep architecture which can combine hierarchical features by using skip connection is designed as the generator network to synthesize the full-dose image. In order to guarantee the synthesized PET image to be close to the real one, we take into account of the estimation error loss in addition to the discriminator feedback to train the generator network. Furthermore, a concatenated 3D c-GANs based progressive refinement scheme is also proposed to further improve the quality of estimated images. Validation was done on a real human brain dataset including both the normal subjects and the subjects diagnosed as mild cognitive impairment (MCI). Experimental results show that our proposed 3D c-GANs method outperforms the benchmark methods and achieves much better performance than the state

Prototype of high resolution PET using resistive electrode position sensitive CdTe detectors

International Nuclear Information System (INIS)

Kikuchi, Yohei; Ishii, Keizo; Matsuyama, Shigeo; Yamazaki, Hiromichi

2008-01-01

Downsizing detector elements makes it possible that spatial resolutions of positron emission tomography (PET) cameras are improved very much. From this point of view, semiconductor detectors are preferable. To obtain high resolution, the pixel type or the multi strip type of semiconductor detectors can be used. However, in this case, there is a low packing ratio problem, because a dead area between detector arrays cannot be neglected. Here, we propose the use of position sensitive semiconductor detectors with resistive electrode. The CdTe detector is promising as a detector for PET camera because of its high sensitivity. In this paper, we report development of prototype of high resolution PET using resistive electrode position sensitive CdTe detectors. We made 1-dimensional position sensitive CdTe detectors experimentally by changing the electrode thickness. We obtained 750 A as an appropriate thickness of position sensitive detectors, and evaluated the performance of the detector using a collimated 241 Am source. A good position resolution of 1.2 mm full width half maximum (FWHM) was obtained. On the basis of the fundamental development of resistive electrode position sensitive detectors, we constructed a prototype of high resolution PET which was a dual head type and was consisted of thirty-two 1-dimensional position sensitive detectors. In conclusion, we obtained high resolutions which are 0.75 mm (FWHM) in transaxial, and 1.5 mm (FWHM) in axial. (author)

Development of a Si-PM-based high-resolution PET system for small animals

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Imaizumi, Masao; Watabe, Tadashi; Shimosegawa, Eku; Hatazawa, Jun; Watabe, Hiroshi; Kanai, Yasukazu

2010-01-01

A Geiger-mode avalanche photodiode (Si-PM) is a promising photodetector for PET, especially for use in a magnetic resonance imaging (MRI) system, because it has high gain and is less sensitive to a static magnetic field. We developed a Si-PM-based depth-of-interaction (DOI) PET system for small animals. Hamamatsu 4 x 4 Si-PM arrays (S11065-025P) were used for its detector blocks. Two types of LGSO scintillator of 0.75 mol% Ce (decay time: ∼45 ns; 1.1 mm x 1.2 mm x 5 mm) and 0.025 mol% Ce (decay time: ∼31 ns; 1.1 mm x 1.2 mm x 6 mm) were optically coupled in the DOI direction to form a DOI detector, arranged in a 11 x 9 matrix, and optically coupled to the Si-PM array. Pulse shape analysis was used for the DOI detection of these two types of LGSOs. Sixteen detector blocks were arranged in a 68 mm diameter ring to form the PET system. Spatial resolution was 1.6 mm FWHM and sensitivity was 0.6% at the center of the field of view. High-resolution mouse and rat images were successfully obtained using the PET system. We confirmed that the developed Si-PM-based PET system is promising for molecular imaging research.

Optimization of fixed titanium dioxide film on PET bottles and visual indicator for water disinfection

Science.gov (United States)

Heredia-Munoz, Manuel Antonio

Water is perhaps the most important resource that sustains human life. According to the World Health Organization (WHO), almost two billion people do not have access to the required water that is needed to satisfy their daily needs and one billion do not have access to clean sources of water for consumption, most of them living in isolated and poor areas around the globe. Poor quality water increases the risk of cholera, typhoid fever and dysentery, and other water-borne illness making this problem a real crisis that humankind is facing. Several water disinfection technologies have been proposed as solutions for this problem. Solar water disinfection using TiO2 coated PET bottles was the alternative that is studied in this work. This technology does not only inactivate bacteria but also disintegrates organic chemicals that can be present in water. The objectives of this work address the optimization of the TiO 2 coated PET bottles technologies. The improvement on the bottle coating process, using two coats of 10% W/V of TiO2 in a solution of vinegar and sodium bicarbonate to form the TiO2 film, the use of a different indigo carmine (1.25 X 10-1mg/pill) concentration in the pill indicator of contamination, the increase of the disinfection rate through shaking the bottles, degradation under intermittent UV radiation and the effect of bottle size on photocatalytic water disinfection were among the most important findings. A new mathematical model that describes better photocatalytic water disinfection in TiO2 coated bottles and simulates water disinfection under different working conditions was another important achievement. These results can now be used to design a strategy for disseminating this technology in areas where it is required and, in that way, generate the greatest positive impact on the people needing safe drinking water.

High performance detector head for PET and PET/MR with continuous crystals and SiPMs

International Nuclear Information System (INIS)

Llosá, G.; Barrillon, P.; Barrio, J.; Bisogni, M.G.; Cabello, J.; Del Guerra, A.; Etxebeste, A.; Gillam, J.E.; Lacasta, C.; Oliver, J.F.; Rafecas, M.; Solaz, C.; Stankova, V.; La Taille, C. de

2013-01-01

A high resolution PET detector head for small animal PET applications has been developed. The detector is composed of a 12mm×12mm continuous LYSO crystal coupled to a 64-channel monolithic SiPM matrix from FBK-irst. Crystal thicknesses of 5 mm and 10 mm have been tested, both yielding an intrinsic spatial resolution around 0.7 mm FWHM with a position determination algorithm that can also provide depth-of-interaction information. The detectors have been tested in a rotating system that makes it possible to acquire tomographic data and reconstruct images of 22 Na sources. An image reconstruction method specifically adapted for continuous crystals has been employed. The Full Width at Half Maximum measured from a point source reconstructed with ML–EM was 0.7 mm with the 5 mm crystal and 0.8 mm with the 10 mm crystal

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

Science.gov (United States)

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

1989-09-01

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

Development of PET insert for simultaneous PET/MR imaging of human brain

Energy Technology Data Exchange (ETDEWEB)

Jung, Jiwoong; Choi, Yong; Jung, Jin Ho; Kim, Sangsu; Im, Ki Chun; Lim, Hyun Keong [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Oh, Changheun; Park, HyunWook; Cho, Gyuseong [Departments of Electrical Engineering and Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

2014-07-29

Recently, there has been great interest on the development of combined PET/MR, which is a useful tool for both functional and anatomic imaging. The purpose of this study was to develop a MR compatible PET insert for simultaneous PET and MR imaging of human brain and to evaluate the performance of the hybrid PET-MRI. The PET insert consisted of 18 detector blocks arranged in a ring of 390 mm diameter with 60 mm axial FOV. Each detector block was composed of 4 × 4 matrix of detector modules, each of which consisted of a 4 × 4 array LYSO coupled to a 4 × 4 GAPD array. The PET gantry was shielded with gold-plated conductive fabric tapes. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuits (PDCs) and then transferred to FPGA-embedded DAQ modules. The PDCs and DAQ modules were enclosed in an aluminum box and located at the rear of the MR bore inside MRI room. 3-T human MRIs of two different vendors were used to evaluate the MR compatibility of developed PET insert. No significant changes of the PET performance and the homogeneity of MR images caused by the non-compatibility of PET-MRI were observed with the 2 different MRIs. The signal intensities of MR images were slightly degraded (<3.6%) with the both MRI systems. The difference between independently and simultaneously acquired PET images of brain phantom was negligibly small (<4.3%). High quality simultaneous brain PET and MRI of 3 normal volunteers were successfully acquired. Experimental results indicate that the high performance compact and lightweight PET insert for hybrid PET/MRI, which could be utilized with the MRI from various manufactures, can be developed using GAPD arrays and charge signal transmission method proposed in this study.

Application of PET and PET/CT imaging for cancer screening

International Nuclear Information System (INIS)

Chen Yenkung; Hu Fenglan; Shen Yehyou; Liao, A.C.; Hung, T.Z.; Su, Chentau; Chen Liangkuang

2004-01-01

The aim of this study was to evaluate the potential application of 18F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) and PET/CT for cancer screening in asymptomatic individuals. Methods: The subjects consisted of 3631 physical check up examinees (1947 men, 1684 women; mean age ±SD, 52.1±8.2 y) with non-specific medical histories. Whole-body FDG PET (or PET/CT), ultrasound and tumor markers were performed on all patients. Focal hypermetabolic areas with intensities equal to or exceeding the level of FDG uptake in the brain and bladder were considered abnormal and interpreted as neoplasia. Follow-up periods were longer than one year. Results: Among the 3631 FDG PET (including 1687 PET/CT), ultrasound and tumor markers examinations, malignant tumors were discovered in 47 examinees (1.29%). PET findings were true-positive in 38 of the 47 cancers (80.9%). In addition, 32 of the 47 cancers were performed with the PET-CT scan. PET detected cancer lesions in 28 of the 32 examinees. However, the CT detected cancer lesions in only 15 of 32 examinees. Conclusion: The sensitivity of FDG PET in the detection of a wide variety of cancers is high. Most cancer can be detected with FDG PET in a resectable stage. CT of the PET/CT for localization and characteristics of the lesion shows an increased specificity of the PET scan. Using ultrasound and tumor markers may complement the PET scan in cancer screening for hepatic and urologic neoplasms. (authors)

Indeterminate findings on oncologic PET/CT: What difference dose PET/MRI make?

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Fraum, Tyler J.; Fowler, Kathryn J.; McConathy, Jonathan; Dehdashti, Farokh [Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis (United States)

2016-12-15

Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-[{sup 18}F]fluoro-D-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment of many different malignancies. Despite this success, PET/CT is often supplemented by MRI to improve assessment of local tumor invasion and to facilitate detection of lesions in organs with high background FDG uptake. Consequently, PET/MRI has the potential to expand the clinical value of PET examinations by increasing reader certainty and reducing the need for subsequent imaging. This study evaluates the ability of FDG-PET/MRI to clarify findings initially deemed indeterminate on clinical FDG-PET/CT studies. A total of 190 oncology patients underwent whole-body PET/CT, immediately followed by PET/MRI utilizing the same FDG administration. Each PET/CT was interpreted by our institution's nuclear medicine service as a standard-of-care clinical examination. Review of these PET/CT reports identified 31 patients (16 %) with indeterminate findings. Two readers evaluated all 31 PET/CT studies, followed by the corresponding PET/MRI studies. A consensus was reached for each case, and changes in interpretation directly resulting from PET/MRI review were recorded. Interpretations were then correlated with follow-up imaging, pathology results, and other diagnostic studies. In 18 of 31 cases with indeterminate findings on PET/CT, PET/MRI resulted in a more definitive interpretation by facilitating the differentiation of infection/inflammation from malignancy (15/18), the accurate localization of FDG-avid lesions (2/18), and the characterization of incidental non-FDG-avid solid organ lesions (1/18). Explanations for improved reader certainty with PET/MRI included the superior soft tissue contrast of MRI and the ability to assess cellular density with diffusion-weighted imaging. The majority (12/18) of such cases had an appropriate standard of reference; in all 12 cases

Indeterminate findings on oncologic PET/CT: What difference dose PET/MRI make?

International Nuclear Information System (INIS)

Fraum, Tyler J.; Fowler, Kathryn J.; McConathy, Jonathan; Dehdashti, Farokh

2016-01-01

Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-["1"8F]fluoro-D-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment of many different malignancies. Despite this success, PET/CT is often supplemented by MRI to improve assessment of local tumor invasion and to facilitate detection of lesions in organs with high background FDG uptake. Consequently, PET/MRI has the potential to expand the clinical value of PET examinations by increasing reader certainty and reducing the need for subsequent imaging. This study evaluates the ability of FDG-PET/MRI to clarify findings initially deemed indeterminate on clinical FDG-PET/CT studies. A total of 190 oncology patients underwent whole-body PET/CT, immediately followed by PET/MRI utilizing the same FDG administration. Each PET/CT was interpreted by our institution's nuclear medicine service as a standard-of-care clinical examination. Review of these PET/CT reports identified 31 patients (16 %) with indeterminate findings. Two readers evaluated all 31 PET/CT studies, followed by the corresponding PET/MRI studies. A consensus was reached for each case, and changes in interpretation directly resulting from PET/MRI review were recorded. Interpretations were then correlated with follow-up imaging, pathology results, and other diagnostic studies. In 18 of 31 cases with indeterminate findings on PET/CT, PET/MRI resulted in a more definitive interpretation by facilitating the differentiation of infection/inflammation from malignancy (15/18), the accurate localization of FDG-avid lesions (2/18), and the characterization of incidental non-FDG-avid solid organ lesions (1/18). Explanations for improved reader certainty with PET/MRI included the superior soft tissue contrast of MRI and the ability to assess cellular density with diffusion-weighted imaging. The majority (12/18) of such cases had an appropriate standard of reference; in all 12 cases, the

Preliminary report on the development of a high resolution PET camera using semiconductor detectors

International Nuclear Information System (INIS)

Kikuchi, Yohei; Ishii, Keizo; Yamazaki, Hiromichi; Matsuyama, Shigeo; Yamaguchi, Takashi; Yamamoto, Yusuke; Sato, Takemi; Aoki, Yasushi; Aoki, Kenichi

2005-01-01

We are developing a PET camera using small semiconductor detectors, whose resolution is equivalent to the physical limit of spatial resolution. First, a coincidence system of 16 Schottky CdTe detectors of 0.5 mm width obtained a resolution of <1 mm and it was confirmed that the Schottky CdTe detector is suitable for high resolution PET. Next, the performance of a pair of 32 channel CdTe arrays (1.2 mm width per channel) was investigated for the development of the prototype of high resolution PET. The time resolution between opposing detector pair was 13 ns (FWHM) when high voltage (700 V) was applied. The image of a 0.6 mm diameter point source was obtained in an experiment with opposing detector arrays using four channels, indicating that, a higher resolution can be achieved with the 32 channel CdTe array

18F-FDG PET and PET/CT in Burkitt's lymphoma

International Nuclear Information System (INIS)

Karantanis, Dimitrios; Durski, Jolanta M.; Lowe, Val J.; Nathan, Mark A.; Mullan, Brian P.; Georgiou, Evangelos; Johnston, Patrick B.; Wiseman, Gregory A.

2010-01-01

Objective: To explore the value of 18 F fluorodeoxy-glucose (FDG) positron emission tomography (PET) in Burkitt's lymphoma. Methods: All Burkitt's lymphoma patients referred for FDG PET or FDG PET/computed tomography (CT) exams at our institution from June 2003 to June 2006 were included. Selected patients were followed and clinical information was reviewed retrospectively. Results from FDG PET-PET/CT, as blindly reviewed by a consensus of two experienced readers, were compared with the status of the disease as determined by other laboratory, clinical and imaging exams and clinical follow-up. FDG PET-PET/CT results were classified as true positive or negative and false positive or negative. The degree of FDG uptake in the positive lesions was semiquantified as maximum standard uptake value (SUVmax). Results: Fifty-seven FDG PET-PET/CT exams were done in 15 patients. Seven exams were done for initial staging, 8 during and 14 after the completion of therapy, and 28 for disease surveillance. For nodal disease FDG PET-PET/CT was true positive in 8, true negative in 47 and false positive in 2 exams (sensitivity 100%, specificity 96%). For extranodal disease FDG PET-PET/CT was true positive in 6, true negative in 48 and false positive in 3 exams (sensitivity 100%, specificity 94%). The mean SUVmax for the positive nodal lesions was 15.7 (range 6.9-21.7, median 18.5) and for extranodal lesions was 14.2 (range 6.2-24.3, median 12.4). Conclusions: FDG PET-PET/CT is sensitive for the detection of viable disease in Burkitt's lymphoma. Affected areas demonstrated high degree of uptake that was reversible upon successful implementation of treatment.

Effect of PET functionalization in composites of

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Cristina Cazan

2017-03-01

Full Text Available The functionalization of polyethylene terephthalate (PET from tire rubber–PET–high density polyethylene (HDPE composites represents a key strategy for improving the composite properties. This is a practical and effective method to improve the interface between matrix (waste tire rubber and fillers (waste PET and HDPE. By PET functionalization, adherence and surface properties of composite materials can be controlled. PET functionalization was performed with polyethylene glycol (PEG 400, 1% and sodium dodecyl sulphate (SDS 1%. The characterization of the components and composite are discussed in terms of surface energy values (evaluated from water contact angle measurements and surface morphology by using scanning electron microscopy (SEM. The structural and conformational changes were investigated by Fourier Transform Infrared (FTIR Spectroscopy while the crystalline structure was studied by X-ray diffraction (XRD. The improved interfacial adhesion, thermal stability and mechanical properties (stress–strain, compression and impact resistance of the composites are correlated with the PET functionalization, with non-ionic (PEG and an anionic surfactant (SDS. The results proved that the interface properties are improved by functionalization of PET. The best mechanical properties were recorded at 30 min moulding. The samples with 45% PET–SDS showed the best combination of mechanical properties: tensile strength (1.56 N/mm2, impact strength (43.72 kJ/m2 and compression (158.78 N/mm2.

Water-equivalent oral contrast agents in dual-modality PET/computed tomography scanning: does a little barium make the difference?

Science.gov (United States)

Kinner, Sonja; Veit-Haibach, Patrick; Lauenstein, Thomas C; Bockisch, Andreas; Antoch, Gerald

2009-03-01

To retrospectively evaluate the performance of two water-equivalent oral contrast agents [locust bean gum (LBG)-mannitol and VoLumen] concerning their potential to distend the bowel while avoiding contrast-associated artifacts in PET/computed tomography. PET/computed tomography examinations of 30 patients with two different oral contrast agents were reviewed. Bowel distension, intraluminal density, and potential contrast-associated artifacts were assessed for stomach, jejunum, and ileum. Statistical significance was tested by Student's t-test. Distension was slightly better in the stomach with VoLumen as compared with LBG-mannitol whereas LBG-mannitol was found to slightly better distend the small bowel. This difference proved to be statistically significant for the jejunum. A statistically significant difference was detected for intraluminal density with higher densities for VoLumen. This difference, however, did not result in a higher incidence of PET artifacts with VoLumen. LBG-mannitol provides excellent bowel distension, thereby avoiding contrast-associated PET artifacts. If this solution is not available, VoLumen provides a satisfactory alternative for bowel distension without relevant PET artifacts.

Development of a novel depth of interaction PET detector using highly multiplexed G-APD cross-strip encoding

Energy Technology Data Exchange (ETDEWEB)

Kolb, A., E-mail: armin.kolb@med.uni-tuebingen.de; Parl, C.; Liu, C. C.; Pichler, B. J. [Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, 72076 Tübingen (Germany); Mantlik, F. [Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University, 72076 Tübingen, Germany and Department of Empirical Inference, Max Planck Institute for Intelligent Systems, 72076 Tübingen (Germany); Lorenz, E. [Max Planck Institute for Physics, Föhringer Ring 6, 80805 München (Germany); Renker, D. [Department of Physics, Technische Universität München, 85748 Garching (Germany)

2014-08-15

Purpose: The aim of this study was to develop a prototype PET detector module for a combined small animal positron emission tomography and magnetic resonance imaging (PET/MRI) system. The most important factor for small animal imaging applications is the detection sensitivity of the PET camera, which can be optimized by utilizing longer scintillation crystals. At the same time, small animal PET systems must yield a high spatial resolution. The measured object is very close to the PET detector because the bore diameter of a high field animal MR scanner is limited. When used in combination with long scintillation crystals, these small-bore PET systems generate parallax errors that ultimately lead to a decreased spatial resolution. Thus, we developed a depth of interaction (DoI) encoding PET detector module that has a uniform spatial resolution across the whole field of view (FOV), high detection sensitivity, compactness, and insensitivity to magnetic fields. Methods: The approach was based on Geiger mode avalanche photodiode (G-APD) detectors with cross-strip encoding. The number of readout channels was reduced by a factor of 36 for the chosen block elements. Two 12 × 2 G-APD strip arrays (25μm cells) were placed perpendicular on each face of a 12 × 12 lutetium oxyorthosilicate crystal block with a crystal size of 1.55 × 1.55 × 20 mm. The strip arrays were multiplexed into two channels and used to calculate the x, y coordinates for each array and the deposited energy. The DoI was measured in step sizes of 1.8 mm by a collimated {sup 18}F source. The coincident resolved time (CRT) was analyzed at all DoI positions by acquiring the waveform for each event and applying a digital leading edge discriminator. Results: All 144 crystals were well resolved in the crystal flood map. The average full width half maximum (FWHM) energy resolution of the detector was 12.8% ± 1.5% with a FWHM CRT of 1.14 ± 0.02 ns. The average FWHM DoI resolution over 12 crystals was 2.90 �

Radioactive spheres without inactive wall for lesion simulation in PET

International Nuclear Information System (INIS)

Bazanez-Borgert, M.; Bundschuh, R.A.; Herz, M.; Martinez, M.J.; Schwaiger, M.; Ziegler, S.I.

2008-01-01

With the growing importance of PET and PET/CT in diagnosis, staging, therapy monitoring and radiotherapy planning, appropriate tools to simulate lesions in phantoms are important. Normally hollow spheres, made of plastic or glass, which can be filled with radioactive solutions, are used. As these spheres have an inactive wall they do not reflect the real situation in the patient and lead to quantification errors in the presence of background activity. We propose spheres made of radioactive wax, which are easy to produce, give a high flexibility to the user and a more accurate quantification. These wax spheres were evaluated for their applicability in PET phantoms and it was found that the activity is not diffusing into the surrounding water in relevant quantities, that they show a sufficient homogeneity, and that their attenuation properties are equivalent to water for photons of PET energies. Recovery coefficients for the wax spheres were measured and compared with those obtained for fillable plastic spheres for diameters of 28, 16, 10, and 6 mm in the presence of background activity. Recovery coefficients of the wax spheres were found to be up to 21% higher than for the fillable spheres. (orig.)

Highly conductive and low cost Ni-PET flexible substrate for efficient dye-sensitized solar cells.

Science.gov (United States)

Su, Haijun; Zhang, Mingyang; Chang, Ya-Huei; Zhai, Peng; Hau, Nga Yu; Huang, Yu-Ting; Liu, Chang; Soh, Ai Kah; Feng, Shien-Ping

2014-04-23

The highly conductive and flexible nickel-polyethylene terephthalate (Ni-PET) substrate was prepared by a facile way including electrodeposition and hot-press transferring. The effectiveness was demonstrated in the counter electrode of dye-sensitized solar cells (DSSCs). The Ni film electrodeposition mechanism, microstructure, and DSSC performance for the Ni-PET flexible substrate were investigated. The uniform and continuous Ni film was first fabricated by electroplating metallic Ni on fluorine-doped tin oxide (FTO) and then intactly transferred onto PET via hot-pressing using Surlyn as the joint adhesive. The obtained flexible Ni-PET substrate shows low sheet resistance of 0.18Ω/□ and good chemical stability for the I(-)/I(3-) electrolyte. A high light-to-electric energy conversion efficiency of 7.89% was demonstrated in DSSCs system based on this flexible electrode substrate due to its high conductivity, which presents an improvement of 10.4% as compared with the general ITO-PEN flexible substrate. This method paves a facile and cost-effective way to manufacture various metals on a plastic nonconducive substrate beneficial for the devices toward flexible and rollable.

FDG-PET status following chemoradiotherapy provides high management impact and powerful prognostic stratification in oesophageal cancer

International Nuclear Information System (INIS)

Duong, Cuong P.; Thomas, Robert J.S.; Hicks, Rodney J.; Drummond, Elizabeth; Weih, LeAnn; Leong, Trevor; Michael, Michael

2006-01-01

The purpose of this study was to evaluate the impact of FDG-PET following chemoradiotherapy (CRT) on treatment planning and survival in patients with oesophageal cancer (OC). Fifty-three consecutive OC patients had a post-treatment PET scan to evaluate tumour response to CRT prior to possible surgery. Baseline pre-CRT PET was performed in 33 patients. Prospectively recorded post-CRT management plans were compared with post-PET treatment. High impact was defined as a change in treatment intent or modality. Survival was analysed using the Kaplan-Meier product limit method and Cox proportional hazards regression model. After completion of CRT, 23/53 patients (43%) achieved complete metabolic response (CMR), as compared with only four (8%) with complete response on computed tomography. High PET impact was observed in 19 patients (36%). CMR was strongly predictive of survival (p<0.008) on multivariate analysis. CMR patients in whom resection was not performed had comparable survival to those (CMR and non-CMR) who underwent resection. The use of post-treatment FDG-PET for assessment of tumour response after CRT changed the clinical management of more than one-third of OC patients. CMR status as assessed by PET powerfully stratified prognosis. Even in the absence of a baseline study, normalisation of uptake at all sites of known tumoral involvement carries a good medium-term prognosis. (orig.)

Assessment of blood flow with (68)Ga-DOTA PET in experimental inflammation: a validation study using (15)O-water.

Science.gov (United States)

Autio, Anu; Saraste, Antti; Kudomi, Nobuyuki; Saanijoki, Tiina; Johansson, Jarkko; Liljenbäck, Heidi; Tarkia, Miikka; Oikonen, Vesa; Sipilä, Hannu T; Roivainen, Anne

2014-01-01

Increased blood flow and vascular permeability are key events in inflammation. Based on the fact that Gadolinium-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (Gd-DOTA) is commonly used in magnetic resonance (MR) imaging of blood flow (perfusion), we evaluated the feasibility of its Gallium-68 labeled DOTA analog ((68)Ga-DOTA) for positron emission tomography (PET) imaging of blood flow in experimental inflammation. Adult, male Sprague-Dawley rats with turpentine oil induced sterile skin/muscle inflammation were anesthetized with isoflurane, and imaged under rest and adenosine-induced hyperemia by means of dynamic 2-min Oxygen-15 labeled water (H2 (15)O) and 30-min (68)Ga-DOTA PET. For the quantification of PET data, regions of interest (ROIs) were defined in the focus of inflammation, healthy muscle, myocardium and heart left ventricle. Radioactivity concentration in the ROIs versus time after injection was determined for both tracers and blood flow was calculated using image-derived input. According to the H2 (15)O PET, blood flow was 0.69 ± 0.15 ml/min/g for inflammation and 0.15 ± 0.03 ml/min/g for muscle during rest. The blood flow remained unchanged during adenosine-induced hyperemia 0.67 ± 0.11 and 0.12 ± 0.03 ml/min/g for inflammation and muscle, respectively, indicating that adenosine has little effect on blood flow in peripheral tissues in rats. High focal uptake of (68)Ga-DOTA was seen at the site of inflammation throughout the 30-min PET imaging. According to the (68)Ga-DOTA PET, blood flow measured as the blood-to-tissue transport rate (K1) was 0.60 ± 0.07 ml/min/g for inflammation and 0.14 ± 0.06 ml/min/g for muscle during rest and 0.63 ± 0.08 ml/min/g for inflammation and 0.09 ± 0.04 ml/min/g for muscle during adenosine-induced hyperemia. The H2 (15)O-based blood flow and (68)Ga-DOTA-based K1 values correlated well (r = 0.94, P DOTA PET imaging is useful for the quantification of increased blood flow induced by inflammation.

Assessment of blood flow with 68Ga-DOTA PET in experimental inflammation: a validation study using 15O-water

Science.gov (United States)

Autio, Anu; Saraste, Antti; Kudomi, Nobuyuki; Saanijoki, Tiina; Johansson, Jarkko; Liljenbäck, Heidi; Tarkia, Miikka; Oikonen, Vesa; Sipilä, Hannu T; Roivainen, Anne

2014-01-01

Increased blood flow and vascular permeability are key events in inflammation. Based on the fact that Gadolinium-1,4,7,10-tetraazacyclododecane-N,N‘,N‘‘,N‘‘‘-tetraacetic acid (Gd-DOTA) is commonly used in magnetic resonance (MR) imaging of blood flow (perfusion), we evaluated the feasibility of its Gallium-68 labeled DOTA analog (68Ga-DOTA) for positron emission tomography (PET) imaging of blood flow in experimental inflammation. Adult, male Sprague-Dawley rats with turpentine oil induced sterile skin/muscle inflammation were anesthetized with isoflurane, and imaged under rest and adenosine-induced hyperemia by means of dynamic 2-min Oxygen-15 labeled water (H2 15O) and 30-min 68Ga-DOTA PET. For the quantification of PET data, regions of interest (ROIs) were defined in the focus of inflammation, healthy muscle, myocardium and heart left ventricle. Radioactivity concentration in the ROIs versus time after injection was determined for both tracers and blood flow was calculated using image-derived input. According to the H2 15O PET, blood flow was 0.69 ± 0.15 ml/min/g for inflammation and 0.15 ± 0.03 ml/min/g for muscle during rest. The blood flow remained unchanged during adenosine-induced hyperemia 0.67 ± 0.11 and 0.12 ± 0.03 ml/min/g for inflammation and muscle, respectively, indicating that adenosine has little effect on blood flow in peripheral tissues in rats. High focal uptake of 68Ga-DOTA was seen at the site of inflammation throughout the 30-min PET imaging. According to the 68Ga-DOTA PET, blood flow measured as the blood-to-tissue transport rate (K1) was 0.60 ± 0.07 ml/min/g for inflammation and 0.14 ± 0.06 ml/min/g for muscle during rest and 0.63 ± 0.08 ml/min/g for inflammation and 0.09 ± 0.04 ml/min/g for muscle during adenosine-induced hyperemia. The H2 15O-based blood flow and 68Ga-DOTA-based K1 values correlated well (r = 0.94, P DOTA PET imaging is useful for the quantification of increased blood flow induced by inflammation. PMID

Dedicated brain PET system of PET/MR for brain research

International Nuclear Information System (INIS)

Cheng, Li; Liu, Yaqiang; Ma, Tianyu; Wang, Shi; Wei, Qingyang; Xu, Tianpeng

2015-01-01

This work is to replace PET ring in human brain PET/MR system with a dedicated wearable PET insert, aimed at improving both patient feasibility and system performance for brain imaging. The designed PET/MR system includes two parts: the inside parts, including a radio frequency (RF) coil and PET ring, are mounted on patient’s head, and the outside part, a MR imager, is dependent of patient. The RF coil is the innermost layer, surrounded by an outer PET-ring layer. They are supported by a MRcompatible structure. And both RF coil and PET detectors are placed inside a standard clinical 3-T MR imager. From the design of the system we can infer that some advantages can be achieved. First, high sensitivity will be achieved with the same amount crystals as the PET ring is more close to region-of-interest area, at a reduced cost. Second, by using a 2-layer depth of interaction (DOI) detector, the parallax effect can be minimized. The resolution will benefit from short positron range caused by magnetic field and smaller ring diameter will also reduce the effect of non-collinearity. Thirdly, as the PET ring is mounted on head, impact of patient motion will be reduced.

Dedicated brain PET system of PET/MR for brain research

Energy Technology Data Exchange (ETDEWEB)

Cheng, Li; Liu, Yaqiang; Ma, Tianyu; Wang, Shi; Wei, Qingyang; Xu, Tianpeng [Institute of Medical Physics, Department of Engineering Physics, Tsinghua University, Beijing (China)

2015-05-18

This work is to replace PET ring in human brain PET/MR system with a dedicated wearable PET insert, aimed at improving both patient feasibility and system performance for brain imaging. The designed PET/MR system includes two parts: the inside parts, including a radio frequency (RF) coil and PET ring, are mounted on patient’s head, and the outside part, a MR imager, is dependent of patient. The RF coil is the innermost layer, surrounded by an outer PET-ring layer. They are supported by a MRcompatible structure. And both RF coil and PET detectors are placed inside a standard clinical 3-T MR imager. From the design of the system we can infer that some advantages can be achieved. First, high sensitivity will be achieved with the same amount crystals as the PET ring is more close to region-of-interest area, at a reduced cost. Second, by using a 2-layer depth of interaction (DOI) detector, the parallax effect can be minimized. The resolution will benefit from short positron range caused by magnetic field and smaller ring diameter will also reduce the effect of non-collinearity. Thirdly, as the PET ring is mounted on head, impact of patient motion will be reduced.

Evaluation of the PET component of simultaneous [18F]choline PET/MRI in prostate cancer: comparison with [18F]choline PET/CT

International Nuclear Information System (INIS)

Wetter, Axel; Lipponer, Christine; Nensa, Felix; Altenbernd, Jens-Christian; Schlosser, Thomas; Lauenstein, Thomas; Heusch, Philipp; Ruebben, Herbert; Bockisch, Andreas; Poeppel, Thorsten; Nagarajah, James

2014-01-01

The aim of this study was to evaluate the positron emission tomography (PET) component of [ 18 F]choline PET/MRI and compare it with the PET component of [ 18 F]choline PET/CT in patients with histologically proven prostate cancer and suspected recurrent prostate cancer. Thirty-six patients were examined with simultaneous [ 18 F]choline PET/MRI following combined [ 18 F]choline PET/CT. Fifty-eight PET-positive lesions in PET/CT and PET/MRI were evaluated by measuring the maximum and mean standardized uptake values (SUV max and SUV mean ) using volume of interest (VOI) analysis. A scoring system was applied to determine the quality of the PET images of both PET/CT and PET/MRI. Agreement between PET/CT and PET/MRI regarding SUV max and SUV mean was tested using Pearson's product-moment correlation and Bland-Altman analysis. All PET-positive lesions that were visible on PET/CT were also detectable on PET/MRI. The quality of the PET images was comparable in both groups. Median SUV max and SUV mean of all lesions were significantly lower in PET/MRI than in PET/CT (5.2 vs 6.1, p max of PET/CT and PET/MRI (R = 0.86, p mean of PET/CT and PET/MRI (R = 0.81, p max of PET/CT vs PET/MRI and -1.12 to +2.23 between SUV mean of PET/CT vs PET/MRI. PET image quality of PET/MRI was comparable to that of PET/CT. A highly significant correlation between SUV max and SUV mean was found. Both SUV max and SUV mean were significantly lower in [ 18 F]choline PET/MRI than in [ 18 F]choline PET/CT. Differences of SUV max and SUV mean might be caused by different techniques of attenuation correction. Furthermore, differences in biodistribution and biokinetics of [ 18 F]choline between the subsequent examinations and in the respective organ systems have to be taken into account. (orig.)

PET and Recycling

Directory of Open Access Journals (Sweden)

Funda Sevencan

2007-08-01

Full Text Available This review aims to clarify the need of decreasing the environmental effects caused by human and draw attention to the increasing environmental effects of plastics wastes. Plastics consist of organic molecules with high density molecules or polymers. Main resources of plastics are the residue of oil rafineries. Several advantages of plastics, have increased the usage continuously. Polyethylene Terephthalate (PET is the most commonly used plastics. PET is used to protect food, drinking water, fruit juice, alcoholic beverage, and food packing films. By the increasing interest on the environmental effects of plastic wastes, concerns on the recyclable packing materials also grew up. Also the daily use of recyclable containers consisting PET have increased. There are five steps for recycling of plastics. These steps are; using large amounts of plastics, collecting them in a big center, classifying and sorting the plastics, reproducing the polymers and obtaining new products with melted plastics. Providing a healthy recycling of plastics, the consumers should have knowledge and responsibility. The consumer should know what he/she has to do before putting the plastics in the recycling containers. Recycling containers and bags should be placed near the sources of plastic wastes. Consequently, the plastic wastes and environmental problems they cause will be on the agenda in future. [TAF Prev Med Bull. 2007; 6(4: 307-312

PET and Recycling

Directory of Open Access Journals (Sweden)

Funda Sevencan

2007-08-01

Full Text Available This review aims to clarify the need of decreasing the environmental effects caused by human and draw attention to the increasing environmental effects of plastics wastes. Plastics consist of organic molecules with high density molecules or polymers. Main resources of plastics are the residue of oil rafineries. Several advantages of plastics, have increased the usage continuously. Polyethylene Terephthalate (PET is the most commonly used plastics. PET is used to protect food, drinking water, fruit juice, alcoholic beverage, and food packing films. By the increasing interest on the environmental effects of plastic wastes, concerns on the recyclable packing materials also grew up. Also the daily use of recyclable containers consisting PET have increased. There are five steps for recycling of plastics. These steps are; using large amounts of plastics, collecting them in a big center, classifying and sorting the plastics, reproducing the polymers and obtaining new products with melted plastics. Providing a healthy recycling of plastics, the consumers should have knowledge and responsibility. The consumer should know what he/she has to do before putting the plastics in the recycling containers. Recycling containers and bags should be placed near the sources of plastic wastes. Consequently, the plastic wastes and environmental problems they cause will be on the agenda in future. [TAF Prev Med Bull 2007; 6(4.000: 307-312

Dedicated mobile high resolution prostate PET imager with an insertable transrectal probe

Science.gov (United States)

Majewski, Stanislaw; Proffitt, James

2010-12-28

A dedicated mobile PET imaging system to image the prostate and surrounding organs. The imaging system includes an outside high resolution PET imager placed close to the patient's torso and an insertable and compact transrectal probe that is placed in close proximity to the prostate and operates in conjunction with the outside imager. The two detector systems are spatially co-registered to each other. The outside imager is mounted on an open rotating gantry to provide torso-wide 3D images of the prostate and surrounding tissue and organs. The insertable probe provides closer imaging, high sensitivity, and very high resolution predominately 2D view of the prostate and immediate surroundings. The probe is operated in conjunction with the outside imager and a fast data acquisition system to provide very high resolution reconstruction of the prostate and surrounding tissue and organs.

Markerless 3D Head Tracking for Motion Correction in High Resolution PET Brain Imaging

DEFF Research Database (Denmark)

Olesen, Oline Vinter

relying on markers. Data-driven motion correction is problematic due to the physiological dynamics. Marker-based tracking is potentially unreliable, and it is extremely hard to validate when the tracking information is correct. The motion estimation is essential for proper motion correction of the PET......This thesis concerns application specific 3D head tracking. The purpose is to improve motion correction in position emission tomography (PET) brain imaging through development of markerless tracking. Currently, motion correction strategies are based on either the PET data itself or tracking devices...... images. Incorrect motion correction can in the worst cases result in wrong diagnosis or treatment. The evolution of a markerless custom-made structured light 3D surface tracking system is presented. The system is targeted at state-of-the-art high resolution dedicated brain PET scanners with a resolution...

(90)Y -PET imaging: Exploring limitations and accuracy under conditions of low counts and high random fraction.

Science.gov (United States)

Carlier, Thomas; Willowson, Kathy P; Fourkal, Eugene; Bailey, Dale L; Doss, Mohan; Conti, Maurizio

2015-07-01

(90)Y -positron emission tomography (PET) imaging is becoming a recognized modality for postinfusion quantitative assessment following radioembolization therapy. However, the extremely low counts and high random fraction associated with (90)Y -PET may significantly impair both qualitative and quantitative results. The aim of this work was to study image quality and noise level in relation to the quantification and bias performance of two types of Siemens PET scanners when imaging (90)Y and to compare experimental results with clinical data from two types of commercially available (90)Y microspheres. Data were acquired on both Siemens Biograph TruePoint [non-time-of-flight (TOF)] and Biograph microcomputed tomography (mCT) (TOF) PET/CT scanners. The study was conducted in three phases. The first aimed to assess quantification and bias for different reconstruction methods according to random fraction and number of true counts in the scan. The NEMA 1994 PET phantom was filled with water with one cylindrical insert left empty (air) and the other filled with a solution of (90)Y . The phantom was scanned for 60 min in the PET/CT scanner every one or two days. The second phase used the NEMA 2001 PET phantom to derive noise and image quality metrics. The spheres and the background were filled with a (90)Y solution in an 8:1 contrast ratio and four 30 min acquisitions were performed over a one week period. Finally, 32 patient data (8 treated with Therasphere(®) and 24 with SIR-Spheres(®)) were retrospectively reconstructed and activity in the whole field of view and the liver was compared to theoretical injected activity. The contribution of both bremsstrahlung and LSO trues was found to be negligible, allowing data to be decay corrected to obtain correct quantification. In general, the recovered activity for all reconstruction methods was stable over the range studied, with a small bias appearing at extremely high random fraction and low counts for iterative algorithms

90Y -PET imaging: Exploring limitations and accuracy under conditions of low counts and high random fraction

International Nuclear Information System (INIS)

Carlier, Thomas; Willowson, Kathy P.; Fourkal, Eugene; Bailey, Dale L.; Doss, Mohan; Conti, Maurizio

2015-01-01

Purpose: 90 Y -positron emission tomography (PET) imaging is becoming a recognized modality for postinfusion quantitative assessment following radioembolization therapy. However, the extremely low counts and high random fraction associated with 90 Y -PET may significantly impair both qualitative and quantitative results. The aim of this work was to study image quality and noise level in relation to the quantification and bias performance of two types of Siemens PET scanners when imaging 90 Y and to compare experimental results with clinical data from two types of commercially available 90 Y microspheres. Methods: Data were acquired on both Siemens Biograph TruePoint [non-time-of-flight (TOF)] and Biograph microcomputed tomography (mCT) (TOF) PET/CT scanners. The study was conducted in three phases. The first aimed to assess quantification and bias for different reconstruction methods according to random fraction and number of true counts in the scan. The NEMA 1994 PET phantom was filled with water with one cylindrical insert left empty (air) and the other filled with a solution of 90 Y . The phantom was scanned for 60 min in the PET/CT scanner every one or two days. The second phase used the NEMA 2001 PET phantom to derive noise and image quality metrics. The spheres and the background were filled with a 90 Y solution in an 8:1 contrast ratio and four 30 min acquisitions were performed over a one week period. Finally, 32 patient data (8 treated with Therasphere ® and 24 with SIR-Spheres ® ) were retrospectively reconstructed and activity in the whole field of view and the liver was compared to theoretical injected activity. Results: The contribution of both bremsstrahlung and LSO trues was found to be negligible, allowing data to be decay corrected to obtain correct quantification. In general, the recovered activity for all reconstruction methods was stable over the range studied, with a small bias appearing at extremely high random fraction and low counts for

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.)

PetIGA-MF: a multi-field high-performance toolbox for structure-preserving B-splines spaces

KAUST Repository

Sarmiento, Adel

2016-10-01

We describe a high-performance solution framework for isogeometric discrete differential forms based on B-splines: PetIGA-MF. Built on top of PetIGA, an open-source library we have built and developed over the last decade, PetIGA-MF is a general multi-field discretization tool. To test the capabilities of our implementation, we solve different viscous flow problems such as Darcy, Stokes, Brinkman, and Navier-Stokes equations. Several convergence benchmarks based on manufactured solutions are presented assuring optimal convergence rates of the approximations, showing the accuracy and robustness of our solver.

Development of dose delivery verification by PET imaging of photonuclear reactions following high energy photon therapy

International Nuclear Information System (INIS)

Janek, S; Svensson, R; Jonsson, C; Brahme, A

2006-01-01

A method for dose delivery monitoring after high energy photon therapy has been investigated based on positron emission tomography (PET). The technique is based on the activation of body tissues by high energy bremsstrahlung beams, preferably with energies well above 20 MeV, resulting primarily in 11 C and 15 O but also 13 N, all positron-emitting radionuclides produced by photoneutron reactions in the nuclei of 12 C, 16 O and 14 N. A PMMA phantom and animal tissue, a frozen hind leg of a pig, were irradiated to 10 Gy and the induced positron activity distributions were measured off-line in a PET camera a couple of minutes after irradiation. The accelerator used was a Racetrack Microtron at the Karolinska University Hospital using 50 MV scanned photon beams. From photonuclear cross-section data integrated over the 50 MV photon fluence spectrum the predicted PET signal was calculated and compared with experimental measurements. Since measured PET images change with time post irradiation, as a result of the different decay times of the radionuclides, the signals from activated 12 C, 16 O and 14 N within the irradiated volume could be separated from each other. Most information is obtained from the carbon and oxygen radionuclides which are the most abundant elements in soft tissue. The predicted and measured overall positron activities are almost equal (-3%) while the predicted activity originating from nitrogen is overestimated by almost a factor of two, possibly due to experimental noise. Based on the results obtained in this first feasibility study the great value of a combined radiotherapy-PET-CT unit is indicated in order to fully exploit the high activity signal from oxygen immediately after treatment and to avoid patient repositioning. With an RT-PET-CT unit a high signal could be collected even at a dose level of 2 Gy and the acquisition time for the PET could be reduced considerably. Real patient dose delivery verification by means of PET imaging seems to be

[18F]FDG PET/CT outperforms [18F]FDG PET/MRI in differentiated thyroid cancer

International Nuclear Information System (INIS)

Vrachimis, Alexis; Wenning, Christian; Weckesser, Matthias; Stegger, Lars; Burg, Matthias Christian; Allkemper, Thomas; Schaefers, Michael

2016-01-01

To evaluate the diagnostic potential of PET/MRI with [ 18 F]FDG in comparison to PET/CT in patients with differentiated thyroid cancer suspected or known to have dedifferentiated. The study included 31 thyroidectomized and remnant-ablated patients who underwent a scheduled [ 18 F]FDG PET/CT scan and were then enrolled for a PET/MRI scan of the neck and thorax. The datasets (PET/CT, PET/MRI) were rated regarding lesion count, conspicuity, diameter and characterization. Standardized uptake values were determined for all [ 18 F]FDG-positive lesions. Histology, cytology, and examinations before and after treatment served as the standards of reference. Of 26 patients with a dedifferentiated tumour burden, 25 were correctly identified by both [ 18 F]FDG PET/CT and PET/MRI. Detection rates by PET/CT and PET/MRI were 97 % (113 of 116 lesions) and 85 % (99 of 113 lesions) for malignant lesions, and 100 % (48 of 48 lesions) and 77 % (37 of 48 lesions) for benign lesions, respectively. Lesion conspicuity was higher on PET/CT for both malignant and benign pulmonary lesions and in the overall rating for malignant lesions (p < 0.001). There was a difference between PET/CT and PET/MRI in overall evaluation of malignant lesions (p < 0.01) and detection of pulmonary metastases (p < 0.001). Surgical evaluation revealed three malignant lesions missed by both modalities. PET/MRI additionally failed to detect 14 pulmonary metastases and 11 benign lesions. In patients with thyroid cancer and suspected or known dedifferentiation, [ 18 F]FDG PET/MRI was inferior to low-dose [ 18 F]FDG PET/CT for the assessment of pulmonary status. However, for the assessment of cervical status, [ 18 F]FDG PET/MRI was equal to contrast-enhanced neck [ 18 F]FDG PET/CT. Therefore, [ 18 F]FDG PET/MRI combined with a low-dose CT scan of the thorax may provide an imaging solution when high-quality imaging is needed and high-energy CT is undesirable or the use of a contrast agent is contraindicated. (orig.)

Positron range in tissue-equivalent materials: experimental microPET studies

Science.gov (United States)

Alva-Sánchez, H.; Quintana-Bautista, C.; Martínez-Dávalos, A.; Ávila-Rodríguez, M. A.; Rodríguez-Villafuerte, M.

2016-09-01

In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with 18F, 13N or 68Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

Highly improved operation of monolithic BGO-PET blocks

Science.gov (United States)

Gonzalez-Montoro, A.; Sanchez, F.; Majewski, S.; Zanettini, S.; Benlloch, J. M.; Gonzalez, A. J.

2017-11-01

In PET scanners both scintillation crystals and photosensors are key components defining the system's performance and cost. Original PET systems used BGO or NaI(Tl) scintillators but achieved limited performance due to its slow decay and relatively low light output. Moreover, NaI(Tl) has low stopping power for 511 keV annihilation photons. In this study we report the possibility to reintroduce BGO crystals, and in particular in the form of monolithic blocks, especially suitable for low-dose large-size PET scanners, offering significantly improved sensitivity at a highly reduced cost compared to LYSO type fast scintillators. We have studied the performance of a monolithic BGO block as large as 50 × 50 × 15 mm3 with black-painted lateral walls to reduce lights spread, enabling accurate photon depth of interaction (DOI) measurements. A directional optical layer, called retro-reflector, was coupled to the entrance face bouncing back the scintillation light in the direction of the emission source and, therefore, adding to the light signal while preserving the narrow light cone distribution. Four configurations namely 12 × 12 and 16 × 16 SiPM arrays (3 mm × 3 mm each) as photosensors, with or without a nanopattern treatment at the crystal exit face, have been studied. This structure consisted of a thin layer of a specific high refractive index material shaped with a periodic nanopattern, increasing the scintillation light extraction. The readout returned information for each SiPM row and column, characterizing the X-Y light distribution projections. We have studied the detector spatial resolution using collimated 22Na sources at normal incidence. The DOI resolution was evaluated using collimated gamma beams with lateral incidence. The overall best detector performance was obtained for the 16× 16 SiPM array offering higher readout granularity. We have determined the spatial resolution for 3 separated DOI layers, obtaining the best results for the DOI region near to

Validating PET segmentation of thoracic lesions-is 4D PET necessary?

DEFF Research Database (Denmark)

Nielsen, M. S.; Carl, J.

2017-01-01

Respiratory-induced motions are prone to degrade the positron emission tomography (PET) signal with the consequent loss of image information and unreliable segmentations. This phantom study aims to assess the discrepancies relative to stationary PET segmentations, of widely used semiautomatic PET...... segmentation methods on heterogeneous target lesions influenced by motion during image acquisition. Three target lesions included dual F-18 Fluoro-deoxy-glucose (FDG) tracer concentrations as high-and low tracer activities relative to the background. Four different tracer concentration arrangements were...... segmented using three SUV threshold methods (Max40%, SUV40% and 2.5SUV) and a gradient based method (GradientSeg). Segmentations in static 3D-PET scans (PETsta) specified the reference conditions for the individual segmentation methods, target lesions and tracer concentrations. The motion included PET...

Imaging and PET - PET/CT imaging

International Nuclear Information System (INIS)

Von Schulthess, G.K.; Hany, Th.F.

2008-01-01

PET/CT has grown because the lack of anatomic landmarks in PET makes 'hardware-fusion' to anatomic cross-sectional data extremely useful. Addition of CT to PET improves specificity, but also sensitivity, and adding PET to CT adds sensitivity and specificity in tumor imaging. The synergistic advantage of adding CT is that the attenuation correction needed for PET data can also be derived from the CT data. This makes PET-CT 25-30% faster than PET alone, leading to higher patient throughput and a more comfortable examination for patients typically lasting 20 minutes or less. FDG-PET-CT appears to provide relevant information in the staging and therapy monitoring of many tumors, such as lung carcinoma, colorectal cancer, lymphoma, gynaecological cancers, melanoma and many others, with the notable exception of prostatic cancer. for this cancer, choline derivatives may possibly become useful radiopharmaceuticals. The published literature on the applications of FDG-PET-CT in oncology is still limited but several designed studies have demonstrated the benefits of PET-CT. (authors)

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests.

Science.gov (United States)

Demir, Mustafa; Toklu, Türkay; Abuqbeitah, Mohammad; Çetin, Hüseyin; Sezgin, H Sezer; Yeyin, Nami; Sönmezoğlu, Kerim

2018-02-01

The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated aspects were spatial resolution, sensitivity, scatter fraction, count rate performance, image quality, count loss and random events correction accuracy. The findings of this study demonstrated superior sensitivity (~ 4 folds) of PET scanner in PET/MR compared to PET/CT system. Image quality test exhibited higher contrast in PET/MR (~ 9%) compared with PET/CT. The scatter fraction of PET/MR was 43.4% at noise equivalent count rate (NECR) peak of 218 kcps and the corresponding activity concentration was 17.7 kBq/cc. Whereas the scatter fraction of PET/CT was found as 39.2% at NECR peak of 72 kcps and activity concentration of 24.3 kBq/cc. The percentage error of the random event correction accuracy was 3.4% and 3.1% in PET/MR and PET/CT, respectively. It was concluded that PET/MR system is about 4 times more sensitive than PET/CT, and the contrast of hot lesions in PET/MR was ~ 9% higher than PET/CT. These outcomes also emphasize the possibility to achieve excellent clinical PET images with low administered dose and/or a short acquisition time in PET/MR.

A high resolution TOF-PET concept with axial geometry and digital SiPM readout

CERN Document Server

Casella, C; Joram, C; Schneider, T

2014-01-01

The axial arrangement of long scintillation crystals is a promising concept in PET instrumentation to address the need for optimized resolution and sensitivity. Individual crystal readout and arrays of wavelength shifter strips placed orthogonally to the crystals lead to a 3D-detection of the annihilations photons. A fully operational demonstrator scanner, developed by the AX-PET collaboration, proved the potential of this concept in terms of energy and spatial resolution as well as sensitivity. This paper describes a feasibility study, performed on axial prototype detector modules with 100 mm long LYSO crystals, read out by the novel digital Silicon Photomultipliers (dSiPM) from Philips. With their highly integrated readout electronics and excellent intrinsic time resolution, dSiPMs allow for compact, axial detector modules which may extend the potential of the axial PET concept by time of fl ight capabilities (TOF-PET). A coincidence time resolution of 211 ps (FWHM) was achieved in the coincidence of two ax...

The effect of intravenous contrast on SUV value in 18F-FDG PET/CT using diagnostic high energy CT

International Nuclear Information System (INIS)

Jeong, Young Jin; Kang, Do Young

2006-01-01

According to the development of CT scanner in PET/CT system, the role of CT unit as a diagnostic tool has been more important. To improve the diagnostic ability of CT scanner, it is a key aspect that CT scanning has to be performed with high dose energy and intravenous (IV) contrast. So we investigated the effect of IV contrast media on the maximum SUV (maxSUV) of normal tissues and pathologic lesions using PET/CT scanner with high dose CT scanning. The study enrolled 13 patients who required PET/CT evaluation. At first, the patients were performed whole body non-contrast CT (NCCT - 120 kVp, 130 mAs) scan. Than contrast enhanced CT (CECT) scan was performed immediately. Finally PET scan was followed. The PET emission data were reconstructed twice, once with the NCCT and again with the CECT. We measured the maxSUV of 10 different body regions that were considered as normal in all patients. Also pathologic lesions were investigated. There were not seen focal artifacts in PET images based on CT with IV contrast agent. Firstly, 130 normal regions in 13 patients were evaluated. The maxSUV was significantly different between two PET images (p < 0.001). The maxSUV was 1.1 ± 0.5 in PET images with CECT-corrected attenuation and 1.0 ± 0.5 in PET images with NCCT-corrected attenuation. The limit of agreement was 0.1 ± 0.3 in Bland-Altman analysis. Especially there were significant differences in 6 of 10 regions, apex and base of the right lung, ascending aorta, segment 6 and segment 8 of the liver and spleen (p <0.05). Secondly, 39 pathologic lesions were evaluated. The maxSUV was significantly different between two PET images (p < 0.001). The maxSUV was 4.7 ± 2.0 in PET images with CECT-corrected attenuation and 4.4 ± 2.0 in PET images with NCCT- corrected attenuation. The limit of agreement was 0.4 ± 0.8 in Bland-Altman analysis. Although there were increases of maxSUVs in the PET images based on CT with IV contrast agent, it was very narrow in the range of limit of

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

International Nuclear Information System (INIS)

Bergeron, Mélanie; Cadorette, Jules; Beaudoin, Jean-François; Lecomte, Roger; Tétrault, Marc-André; Leroux, Jean-Daniel; Fontaine, Réjean

2014-01-01

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 mm 3 ), 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

Use of FDG PET/CT for investigation of febrile neutropenia: evaluation in high-risk cancer patients

International Nuclear Information System (INIS)

Guy, Stephen D.; Tramontana, Adrian R.; Worth, Leon J.; Thursky, Karin A.; Slavin, Monica A.; Lau, Eddie; Hicks, Rodney J.; Seymour, John F.

2012-01-01

Febrile neutropenia (FNP) is a frequent complication of cancer care and evaluation often fails to identify a cause. [ 18 F]FDG PET/CT has the potential to identify inflammatory and infectious foci, but its potential role as an investigation for persistent FNP has not previously been explored. The aim of this study was to prospectively evaluate the clinical utility of FDG PET/CT in patients with cancer and severe neutropenia and five or more days of persistent fever despite antibiotic therapy. Adult patients with a diagnosis of an underlying malignancy and persistent FNP (temperature ≥38 C and neutrophil count <500 cells/μl for 5 days) underwent FDG PET/CT as an adjunct to conventional evaluation and management. The study group comprised 20 patients with FNP who fulfilled the eligibility criteria and underwent FDG PET/CT in addition to conventional evaluation. The median neutrophil count on the day of the FDG PET/CT scan was 30 cells/μl (range 0-730 cells/μl). Conventional evaluation identified 14 distinct sites of infection, 13 (93 %) of which were also identified by FDG PET/CT, including all deep tissue infections. FDG PET/CT identified 9 additional likely infection sites, 8 of which were subsequently confirmed as ''true positives'' by further investigations. FDG PET/CT was deemed to be of 'high' clinical impact in 15 of the 20 patients (75 %). This study supports the utility of FDG PET/CT scanning in severely neutropenic patients with five or more days of fever. Further evaluation of the contribution of FDG PET/CT in the management of FNP across a range of underlying malignancies is required. (orig.)

Use of FDG PET/CT for investigation of febrile neutropenia: evaluation in high-risk cancer patients

Energy Technology Data Exchange (ETDEWEB)

Guy, Stephen D.; Tramontana, Adrian R. [Western Health, Department of Infectious Diseases, Private Bag, Footscray, Victoria (Australia); University of Melbourne, Parkville, Victoria (Australia); Worth, Leon J.; Thursky, Karin A.; Slavin, Monica A. [University of Melbourne, Parkville, Victoria (Australia); Peter MacCallum Cancer Centre, Department of Infectious Diseases, Melbourne, Victoria (Australia); Lau, Eddie; Hicks, Rodney J. [University of Melbourne, Parkville, Victoria (Australia); Peter MacCallum Cancer Centre, Centre for Cancer Imaging, Melbourne, Victoria (Australia); Seymour, John F. [University of Melbourne, Parkville, Victoria (Australia); Peter MacCallum Cancer Centre, Department of Haematology, Melbourne, Victoria (Australia)

2012-08-15

Febrile neutropenia (FNP) is a frequent complication of cancer care and evaluation often fails to identify a cause. [{sup 18} F]FDG PET/CT has the potential to identify inflammatory and infectious foci, but its potential role as an investigation for persistent FNP has not previously been explored. The aim of this study was to prospectively evaluate the clinical utility of FDG PET/CT in patients with cancer and severe neutropenia and five or more days of persistent fever despite antibiotic therapy. Adult patients with a diagnosis of an underlying malignancy and persistent FNP (temperature {>=}38 C and neutrophil count <500 cells/{mu}l for 5 days) underwent FDG PET/CT as an adjunct to conventional evaluation and management. The study group comprised 20 patients with FNP who fulfilled the eligibility criteria and underwent FDG PET/CT in addition to conventional evaluation. The median neutrophil count on the day of the FDG PET/CT scan was 30 cells/{mu}l (range 0-730 cells/{mu}l). Conventional evaluation identified 14 distinct sites of infection, 13 (93 %) of which were also identified by FDG PET/CT, including all deep tissue infections. FDG PET/CT identified 9 additional likely infection sites, 8 of which were subsequently confirmed as ''true positives'' by further investigations. FDG PET/CT was deemed to be of 'high' clinical impact in 15 of the 20 patients (75 %). This study supports the utility of FDG PET/CT scanning in severely neutropenic patients with five or more days of fever. Further evaluation of the contribution of FDG PET/CT in the management of FNP across a range of underlying malignancies is required. (orig.)

The accuracy of {sup 68}Ga-PSMA PET/CT in primary lymph node staging in high-risk prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Oebek, Can; Doganca, Tuenkut [Acibadem Taksim Hospital, Department of Urology, Istanbul (Turkey); Demirci, Emre [Sisli Etfal Training and Research Hospital, Department of Nuclear Medicine, Istanbul (Turkey); Ocak, Meltem [Istanbul University, Faculty of Pharmacy, Department of Pharmaceutical Technology, Istanbul (Turkey); Kural, Ali Riza [Acibadem University, Department of Urology, Istanbul (Turkey); Yildirim, Asif [Istanbul Medeniyet University, Department of Urology, Istanbul (Turkey); Yuecetas, Ugur [Istanbul Training and Research Hospital, Department of Urology, Istanbul (Turkey); Demirdag, Cetin [Istanbul University, Cerrahpasa School of Medicine, Department of Urology, Istanbul (Turkey); Erdogan, Sarper M. [Istanbul University, Cerrahpasa School of Medicine, Department of Public Health, Istanbul (Turkey); Kabasakal, Levent [Istanbul University, Cerrahpasa School of Medicine, Department of Nuclear Medicine, Istanbul (Turkey); Collaboration: Members of Urooncology Association, Turkey

2017-10-15

To assess the diagnostic accuracy of {sup 68}Ga-PSMA PET in predicting lymph node (LN) metastases in primary N staging in high-risk and very high-risk nonmetastatic prostate cancer in comparison with morphological imaging. This was a multicentre trial of the Society of Urologic Oncology in Turkey in conjunction with the Nuclear Medicine Department of Cerrahpasa School of Medicine, Istanbul University. Patients were accrued from eight centres. Patients with high-risk and very high-risk disease scheduled to undergo surgical treatment with extended LN dissection between July 2014 and October 2015 were included. Either MRI or CT was used for morphological imaging. PSMA PET/CT was performed and evaluated at a single centre. Sensitivity, specificity and accuracy were calculated for the detection of lymphatic metastases by PSMA PET/CT and morphological imaging. Kappa values were calculated to evaluate the correlation between the numbers of LN metastases detected by PSMA PET/CT and by histopathology. Data on 51 eligible patients are presented. The sensitivity, specificity and accuracy of PSMA PET in detecting LN metastases in the primary setting were 53%, 86% and 76%, and increased to 67%, 88% and 81% in the subgroup with of patients with ≥15 LN removed. Kappa values for the correlation between imaging and pathology were 0.41 for PSMA PET and 0.18 for morphological imaging. PSMA PET/CT is superior to morphological imaging for the detection of metastatic LNs in patients with primary prostate cancer. Surgical dissection remains the gold standard for precise lymphatic staging. (orig.)

Quantitative assessment of regional myocardial flow reserve using Tc-99m-sestamibi imaging. Comparison with results of O-15 water PET

International Nuclear Information System (INIS)

Tsukamoto, Takahiro; Ito, Yoshinori; Noriyasu, Kazuyuki; Morita, Koichi; Katoh, Chietsugu; Okamoto, Hiroshi; Tamaki, Nagara

2005-01-01

The aims of this study were to develop a method for quantitative estimation of the myocardial blood flow index (MBFI) and myocardial flow reserve (MFR) of the whole left ventricle using 99m technetium (Tc-99m)-sestamibi imaging. Twenty-two patients with suspected coronary artery disease and 7 controls underwent both Tc-99m-sestamibi imaging and O-15 water positron emission tomography (PET). The global MBFI was calculated on the basis of the microsphere model from the ratio of the myocardial count to the area under the time-activity curve on the aortic arch. The regional MBFI was calculated from the relative distributions of Tc-99m-sestamibi uptake values. The regional MBFI and MFR (Tc-MFR) obtained using single-photon emission computed tomography were compared with the myocardial blood flow (MBF) and MFR (PET-MFR) obtained using PET as the gold standard. Regional MBFI significantly correlated with the MBF obtained using PET. Regional Tc-MFR also correlated with the regional PET-MER, with some underestimation. These results indicate that regional MBF and MFR may be estimated by dynamic Tc-99m-sestamibi imaging and can be used for the early detection and estimation of the functional severity of coronary lesions without the need for a PET camera. (author)

SU-F-I-59: Quality Assurance Phantom for PET/CT Alignment and Attenuation Correction

International Nuclear Information System (INIS)

Lin, T; Hamacher, K

2016-01-01

Purpose: This study utilizes a commercial PET/CT phantom to investigate two specific properties of a PET/CT system: the alignment accuracy of PET images with those from CT used for attenuation correction and the accuracy of this correction in PET images. Methods: A commercial PET/CT phantom consisting of three aluminum rods, two long central cylinders containing uniform activity, and attenuating materials such as air, water, bone and iodine contrast was scanned using a standard PET/CT protocol. Images reconstructed with 2 mm slice thickness and a 512 by 512 matrix were obtained. The center of each aluminum rod in the PET and CT images was compared to evaluate alignment accuracy. ROIs were drawn on transaxial images of the central rods at each section of attenuating material to determine the corrected activity (in BQML). BQML values were graphed as a function of slice number to provide a visual representation of the attenuation-correction throughout the whole phantom. Results: Alignment accuracy is high between the PET and CT images. The maximum deviation between the two in the axial plane is less than 1.5 mm, which is less than the width of a single pixel. BQML values measured along different sections of the large central rods are similar among the different attenuating materials except iodine contrast. Deviation of BQML values in the air and bone sections from the water section is less than 1%. Conclusion: Accurate alignment of PET and CT images is critical to ensure proper calculation and application of CT-based attenuation correction. This study presents a simple and quick method to evaluate the two with a single acquisition. As the phantom also includes spheres of increasing diameter, this could serve as a straightforward means to annually evaluate the status of a modern PET/CT system.

SU-F-I-59: Quality Assurance Phantom for PET/CT Alignment and Attenuation Correction

Energy Technology Data Exchange (ETDEWEB)

Lin, T; Hamacher, K [Columbia University Medical Center, New York, NY (United States)

2016-06-15

Purpose: This study utilizes a commercial PET/CT phantom to investigate two specific properties of a PET/CT system: the alignment accuracy of PET images with those from CT used for attenuation correction and the accuracy of this correction in PET images. Methods: A commercial PET/CT phantom consisting of three aluminum rods, two long central cylinders containing uniform activity, and attenuating materials such as air, water, bone and iodine contrast was scanned using a standard PET/CT protocol. Images reconstructed with 2 mm slice thickness and a 512 by 512 matrix were obtained. The center of each aluminum rod in the PET and CT images was compared to evaluate alignment accuracy. ROIs were drawn on transaxial images of the central rods at each section of attenuating material to determine the corrected activity (in BQML). BQML values were graphed as a function of slice number to provide a visual representation of the attenuation-correction throughout the whole phantom. Results: Alignment accuracy is high between the PET and CT images. The maximum deviation between the two in the axial plane is less than 1.5 mm, which is less than the width of a single pixel. BQML values measured along different sections of the large central rods are similar among the different attenuating materials except iodine contrast. Deviation of BQML values in the air and bone sections from the water section is less than 1%. Conclusion: Accurate alignment of PET and CT images is critical to ensure proper calculation and application of CT-based attenuation correction. This study presents a simple and quick method to evaluate the two with a single acquisition. As the phantom also includes spheres of increasing diameter, this could serve as a straightforward means to annually evaluate the status of a modern PET/CT system.

MRI-assisted PET motion correction for neurologic studies in an integrated MR-PET scanner.

Science.gov (United States)

Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B; Michel, Christian J; El Fakhri, Georges; Schmand, Matthias; Sorensen, A Gregory

2011-01-01

Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MRI data can be used for motion tracking. In this work, a novel algorithm for data processing and rigid-body motion correction (MC) for the MRI-compatible BrainPET prototype scanner is described, and proof-of-principle phantom and human studies are presented. To account for motion, the PET prompt and random coincidences and sensitivity data for postnormalization were processed in the line-of-response (LOR) space according to the MRI-derived motion estimates. The processing time on the standard BrainPET workstation is approximately 16 s for each motion estimate. After rebinning in the sinogram space, the motion corrected data were summed, and the PET volume was reconstructed using the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed, and motion estimates were obtained using 2 high-temporal-resolution MRI-based motion-tracking techniques. After accounting for the misalignment between the 2 scanners, perfectly coregistered MRI and PET volumes were reproducibly obtained. The MRI output gates inserted into the PET list-mode allow the temporal correlation of the 2 datasets within 0.2 ms. The Hoffman phantom volume reconstructed by processing the PET data in the LOR space was similar to the one obtained by processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the procedure. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 s and 20 ms, respectively. Motion-deblurred PET images, with excellent delineation of specific brain structures, were obtained using these 2 MRI

PET imaging for brain function

International Nuclear Information System (INIS)

Fukuda, Hiroshi

2003-01-01

Described are the principle of PET and its characteristics, imaging of human brain function, mapping of detailed human cerebral functions and PET imaging of nerve transmission. Following compounds labeled by positron emitters are used for PET imaging of brain functions: for blood flow and oxygen metabolism, 15 O-O 2 gas, water and carbon dioxide; for energy metabolism, 18 F-fluorodeoxyglucose; and for nerve transmission functions in receptor binding, transporter, transmitter synthesis and enzyme, 11 C- or 18 F-dopamine, serotonin and their analogues, and acetylcholine analogues. For brain mapping, examples of cognition tasks, results and their statistics are presented with images for blood flow. Nerve transmissions in schizophrenia and Alzheimer disease are imaged with labeled analogues of dopamine and acetylcholine, respectively. PET is becoming more and more important in the field of psychiatric science particularly in the coming society of increasing aged people. (N.I.)

PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients.

Science.gov (United States)

Burger, C; Goerres, G; Schoenes, S; Buck, A; Lonn, A H R; Von Schulthess, G K

2002-07-01

The CT data acquired in combined PET/CT studies provide a fast and essentially noiseless source for the correction of photon attenuation in PET emission data. To this end, the CT values relating to attenuation of photons in the range of 40-140 keV must be transformed into linear attenuation coefficients at the PET energy of 511 keV. As attenuation depends on photon energy and the absorbing material, an accurate theoretical relation cannot be devised. The transformation implemented in the Discovery LS PET/CT scanner (GE Medical Systems, Milwaukee, Wis.) uses a bilinear function based on the attenuation of water and cortical bone at the CT and PET energies. The purpose of this study was to compare this transformation with experimental CT values and corresponding PET attenuation coefficients. In 14 patients, quantitative PET attenuation maps were calculated from germanium-68 transmission scans, and resolution-matched CT images were generated. A total of 114 volumes of interest were defined and the average PET attenuation coefficients and CT values measured. From the CT values the predicted PET attenuation coefficients were calculated using the bilinear transformation. When the transformation was based on the narrow-beam attenuation coefficient of water at 511 keV (0.096 cm(-1)), the predicted attenuation coefficients were higher in soft tissue than the measured values. This bias was reduced by replacing 0.096 cm(-1) in the transformation by the linear attenuation coefficient of 0.093 cm(-1) obtained from germanium-68 transmission scans. An analysis of the corrected emission activities shows that the resulting transformation is essentially equivalent to the transmission-based attenuation correction for human tissue. For non-human material, however, it may assign inaccurate attenuation coefficients which will also affect the correction in neighbouring tissue.

Evaluation of a high resolution silicon PET insert module

Energy Technology Data Exchange (ETDEWEB)

Grkovski, Milan, E-mail: milan.grkovski@ijs.si [Jožef Stefan Institute, Ljubljana (Slovenia); Memorial Sloan Kettering Cancer Center, New York, NY (United States); Brzezinski, Karol [IFIC/CSIC, Valencia (Spain); Cindro, Vladimir [Jožef Stefan Institute, Ljubljana (Slovenia); Clinthorne, Neal H. [University of Michigan, Ann Arbor, MI (United States); Kagan, Harris [Ohio State University, Columbus, OH (United States); Lacasta, Carlos [IFIC/CSIC, Valencia (Spain); Mikuž, Marko [Jožef Stefan Institute, Ljubljana (Slovenia); Solaz, Carles [IFIC/CSIC, Valencia (Spain); Studen, Andrej [Jožef Stefan Institute, Ljubljana (Slovenia); Weilhammer, Peter [Ohio State University, Columbus, OH (United States); Žontar, Dejan [Jožef Stefan Institute, Ljubljana (Slovenia)

2015-07-11

Conventional PET systems can be augmented with additional detectors placed in close proximity of the region of interest. We developed a high resolution PET insert module to evaluate the added benefit of such a combination. The insert module consists of two back-to-back 1 mm thick silicon sensors, each segmented into 1040 1 mm{sup 2} pads arranged in a 40 by 26 array. A set of 16 VATAGP7.1 ASICs and a custom assembled data acquisition board were used to read out the signal from the insert module. Data were acquired in slice (2D) geometry with a Jaszczak phantom (rod diameters of 1.2–4.8 mm) filled with {sup 18}F-FDG and the images were reconstructed with ML-EM method. Both data with full and limited angular coverage from the insert module were considered and three types of coincidence events were combined. The ratio of high-resolution data that substantially improves quality of the reconstructed image for the region near the surface of the insert module was estimated to be about 4%. Results from our previous studies suggest that such ratio could be achieved at a moderate technological expense by using an equivalent of two insert modules (an effective sensor thickness of 4 mm)

Impact of high (131)I-activities on quantitative (124)I-PET

DEFF Research Database (Denmark)

Braad, P E N; Hansen, Søren B.; Høilund-Carlsen, P F

2015-01-01

relevant [Formula: see text]I/[Formula: see text]I-activities were performed on a clinical PET/CT-system. Noise equivalent count rate (NECR) curves and quantitation accuracy were determined from repeated scans performed over several weeks on a decaying NEMA NU-2 1994 cylinder phantom initially filled...... [Formula: see text]I-activities was good and image quantification unaffected except at very high count rates. Quantitation accuracy and contrast recovery were uninfluenced at [Formula: see text]I-activities below 1000 MBq, whereas image noise was slightly increased. The NECR peaked at 550 MBq of [Formula......: see text]I, where it was 2.8 times lower than without [Formula: see text]I in the phantom. Quantitative peri-therapeutic [Formula: see text]I-PET is feasible....

Application of PET in breast cancer

International Nuclear Information System (INIS)

Noh, Dong Young

2002-01-01

Positron emission tomography (PET) is an imaging method that employs radionuclide and tomography techniques. Since 1995, we applied PET not only to the diagnosis of breast cancer but also to the detection of abnormalities in the augmented breast and to the detection of metastasis. Until 2001, we evaluated 242 breast cases by PET at PET center of Seoul National University Hospital. Our group has reported serially at the international journals. In the firtst report, PET showed high sensitivity for detecting breast cancer, both the primary and axillary node metastasis. A total of 27 patients underwent breast operations based on PET results at Seoul National University Hospital from 1995 to 1996. The diagnostic accuracy of PET were 97% for the primary tumor mass and 96% for axillary lymph node metastasis. In case of the breast augmented, PET also showed excellent diagnostic results for primary breast cancer and axillary lymph node metastasis where mammography and ultrasound could not diagnose properly. PET also had outstanding results in the detection of recurrent or metastatic breast cancer(sensitivity 94%, specificity 80%, accuracy 89%). In addition, our study gave some evidence that PET could be applied further to evaluate the growth rate of tumors by measuring SUV, and finally to prognosticated the disease. PET could also be applied to evaluate the response after chemotherapy to measure its metabolic rate and size. In conclsion, PET is a highly sensitive, accurate diagnostic tool for breast cancer of primary lesion in various conditions including metastasis

Recommendations for the use of PET and PET-CT for radiotherapy planning in research projects.

Science.gov (United States)

Somer, E J; Pike, L C; Marsden, P K

2012-08-01

With the increasing use of positron emission tomography (PET) for disease staging, follow-up and therapy monitoring in a number of oncological indications there is growing interest in the use of PET and PET-CT for radiation treatment planning. In order to create a strong clinical evidence base for this, it is important to ensure that research data are clinically relevant and of a high quality. Therefore the National Cancer Research Institute PET Research Network make these recommendations to assist investigators in the development of radiotherapy clinical trials involving the use of PET and PET-CT. These recommendations provide an overview of the current literature in this rapidly evolving field, including standards for PET in clinical trials, disease staging, volume delineation, intensity modulated radiotherapy and PET-augmented planning techniques, and are targeted at a general audience. We conclude with specific recommendations for the use of PET in radiotherapy planning in research projects.

PET Imaging Stability Measurements During Simultaneous Pulsing of Aggressive MR Sequences on the SIGNA PET/MR System.

Science.gov (United States)

Deller, Timothy W; Khalighi, Mohammad Mehdi; Jansen, Floris P; Glover, Gary H

2018-01-01

The recent introduction of simultaneous whole-body PET/MR scanners has enabled new research taking advantage of the complementary information obtainable with PET and MRI. One such application is kinetic modeling, which requires high levels of PET quantitative stability. To accomplish the required PET stability levels, the PET subsystem must be sufficiently isolated from the effects of MR activity. Performance measurements have previously been published, demonstrating sufficient PET stability in the presence of MR pulsing for typical clinical use; however, PET stability during radiofrequency (RF)-intensive and gradient-intensive sequences has not previously been evaluated for a clinical whole-body scanner. In this work, PET stability of the GE SIGNA PET/MR was examined during simultaneous scanning of aggressive MR pulse sequences. Methods: PET performance tests were acquired with MR idle and during simultaneous MR pulsing. Recent system improvements mitigating RF interference and gain variation were used. A fast recovery fast spin echo MR sequence was selected for high RF power, and an echo planar imaging sequence was selected for its high heat-inducing gradients. Measurements were performed to determine PET stability under varying MR conditions using the following metrics: sensitivity, scatter fraction, contrast recovery, uniformity, count rate performance, and image quantitation. A final PET quantitative stability assessment for simultaneous PET scanning during functional MRI studies was performed with a spiral in-and-out gradient echo sequence. Results: Quantitation stability of a 68 Ge flood phantom was demonstrated within 0.34%. Normalized sensitivity was stable during simultaneous scanning within 0.3%. Scatter fraction measured with a 68 Ge line source in the scatter phantom was stable within the range of 40.4%-40.6%. Contrast recovery and uniformity were comparable for PET images acquired simultaneously with multiple MR conditions. Peak noise equivalent count

{sup 18}F-FDG PET and PET/CT in Burkitt's lymphoma

Energy Technology Data Exchange (ETDEWEB)

Karantanis, Dimitrios, E-mail: dkarantanis@nuclmed.ne [Division of Nuclear Medicine, Department of Radiology, Mayo Clinic, Rochester, MN (United States); Durski, Jolanta M.; Lowe, Val J.; Nathan, Mark A.; Mullan, Brian P. [Division of Nuclear Medicine, Department of Radiology, Mayo Clinic, Rochester, MN (United States); Georgiou, Evangelos [Medical Physics Department, Medical School, University of Athens (Greece); Johnston, Patrick B. [Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN (United States); Wiseman, Gregory A. [Division of Nuclear Medicine, Department of Radiology, Mayo Clinic, Rochester, MN (United States)

2010-07-15

Objective: To explore the value of {sup 18}F fluorodeoxy-glucose (FDG) positron emission tomography (PET) in Burkitt's lymphoma. Methods: All Burkitt's lymphoma patients referred for FDG PET or FDG PET/computed tomography (CT) exams at our institution from June 2003 to June 2006 were included. Selected patients were followed and clinical information was reviewed retrospectively. Results from FDG PET-PET/CT, as blindly reviewed by a consensus of two experienced readers, were compared with the status of the disease as determined by other laboratory, clinical and imaging exams and clinical follow-up. FDG PET-PET/CT results were classified as true positive or negative and false positive or negative. The degree of FDG uptake in the positive lesions was semiquantified as maximum standard uptake value (SUVmax). Results: Fifty-seven FDG PET-PET/CT exams were done in 15 patients. Seven exams were done for initial staging, 8 during and 14 after the completion of therapy, and 28 for disease surveillance. For nodal disease FDG PET-PET/CT was true positive in 8, true negative in 47 and false positive in 2 exams (sensitivity 100%, specificity 96%). For extranodal disease FDG PET-PET/CT was true positive in 6, true negative in 48 and false positive in 3 exams (sensitivity 100%, specificity 94%). The mean SUVmax for the positive nodal lesions was 15.7 (range 6.9-21.7, median 18.5) and for extranodal lesions was 14.2 (range 6.2-24.3, median 12.4). Conclusions: FDG PET-PET/CT is sensitive for the detection of viable disease in Burkitt's lymphoma. Affected areas demonstrated high degree of uptake that was reversible upon successful implementation of treatment.

Development of high shrinkage polyethylene terephthalate (PET) shape memory polymer tendons for concrete crack closure

Science.gov (United States)

Teall, Oliver; Pilegis, Martins; Sweeney, John; Gough, Tim; Thompson, Glen; Jefferson, Anthony; Lark, Robert; Gardner, Diane

2017-04-01

The shrinkage force exerted by restrained shape memory polymers (SMPs) can potentially be used to close cracks in structural concrete. This paper describes the physical processing and experimental work undertaken to develop high shrinkage die-drawn polyethylene terephthalate (PET) SMP tendons for use within a crack closure system. The extrusion and die-drawing procedure used to manufacture a series of PET tendon samples is described. The results from a set of restrained shrinkage tests, undertaken at differing activation temperatures, are also presented along with the mechanical properties of the most promising samples. The stress developed within the tendons is found to be related to the activation temperature, the cross-sectional area and to the draw rate used during manufacture. Comparisons with commercially-available PET strip samples used in previous research are made, demonstrating an increase in restrained shrinkage stress by a factor of two for manufactured PET filament samples.

PET-Probe: Evaluation of Technical Performance and Clinical Utility of a Handheld High-Energy Gamma Probe in Oncologic Surgery.

Science.gov (United States)

Gulec, Seza A; Daghighian, Farhad; Essner, Richard

2016-12-01

Positron emission tomography (PET) has become an invaluable part of patient evaluation in surgical oncology. PET is less than optimal for detecting lesions PET-positive lesions can be challenging as a result of difficulties in surgical exposure. We undertook this investigation to assess the utility of a handheld high-energy gamma probe (PET-Probe) for intraoperative identification of 18 F-deoxyglucose (FDG)-avid tumors. Forty patients underwent a diagnostic whole-body FDG-PET scan for consideration for surgical exploration and resection. Before surgery, all patients received an intravenous injection of 7 to 10 mCi of FDG. At surgery, the PET-Probe was used to determine absolute counts per second at the known tumor site(s) demonstrated by whole-body PET and at adjacent normal tissue (at least 4 cm away from tumor-bearing sites). Tumor-to-background ratios were calculated. Thirty-two patients (80%) underwent PET-Probe-guided surgery with therapeutic intent in a recurrent or metastatic disease setting. Eight patients underwent surgery for diagnostic exploration. Anatomical locations of the PET-identified lesions were neck and supraclavicular (n = 8), axilla (n = 5), groin and deep iliac (n = 4), trunk and extremity soft tissue (n = 3), abdominal and retroperitoneal (n = 19), and lung (n = 2). PET-Probe detected all PET-positive lesions. The PET-Probe was instrumental in localization of lesions in 15 patients that were not immediately apparent by surgical exploration. The PET-Probe identified all lesions demonstrated by PET scanning and, in selected cases, was useful in localizing FDG-avid disease not seen with conventional PET scanning.

Panel Board From Coconut Fibre And Pet Bottle

Science.gov (United States)

Ngadiman, Norhayati; Kaamin, Masiri; Abd. Kadir, Aslila; Sahat, Suhaila; Zaini, Aziza; Raihana Nor Zentan, Siti; Ain Ahmad, Nur; Amran, Wan Haizatul Aisyhah Wan

2018-03-01

The rate of global deforestation and its impact on the environment has led particle board manufacture to search for alternative feedstock, especially in countries where wood is less available compared to other cellulosic natural product. Based on the properties of coconut fibre and PET bottle, these two materials can be recycle as raw material for manufacture of panel board. As for this study, the coconut fibre were used as the filler and PET bottle as outer lining of the panel board. Two types of coconut fibre were used which are grinding and un-grinding coconut fibre. At first, the coconut fibre are undergoes softening, grinding, drying and sieving process, while PET bottle was cleaning, shredding, sieving before compacted using hydraulic hot press machine. There are four types of testing that been carried out which are swelling, water absorption, Modulus of Elasticity (MOE) and Modulus of Rupture (MOR). The result show the conventional board has the highest value for MOE test, so it's indicate that the conventional board is less strength from the coconut fibre board. As for water absorption test, the average water absorption of coconut fibre based panel board is less than conventional board. Overall, the coconut fibre board is better than conventional panel board because coconut fibre board are less swelling, has low water absorption, high modulus of rupture and low modulus of elasticity. Based on the finding, this coconut fibre panel board has potential as a stronger and long-lasting panel board than the conventional board in the market. Other than that, the panel also have their own aesthetic value since the recycled plastic bottle used as outer lining is colourful and giving aesthetic value.

Assessment of Physiological Equivalent Temperature (PET in Transitional Spaces of a High-Rise Building

Directory of Open Access Journals (Sweden)

Nooriati Taib

2016-01-01

Full Text Available One passive approach that can significantly reduce energy usage in high-rise buildings is through the creation of non-air conditioned spaces such as transitional spaces. Optimizing passive design would reduce wastage associated with the building’s energy consumption. The study measures the thermal comfort of three types of transitional spaces (sky court, balcony, and rooftop in a high-rise office building. Based on the assessment of Physiological Equivalent Temperature (PET, the outcome showed significant differences in PET in all locations in both wet and dry season. The effectiveness of such area can be improved with the contributions of landscape, maximizing natural ventilation and day lighting where possible.

H2WHOA - 6 to 8 glasses of water an hour: how water can distinguish physiological from pathological uptake in the GIT on PET/CT scans

International Nuclear Information System (INIS)

Crowther, M. D.

2009-01-01

Full text:Objectives: To determine the effectiveness of water as a negative contrast agent in PET/CT. To determine the amount and timing of water to be administered in order to evaluate specific regions of the gastro-intestinal tract (GIT). To evaluate whether the use of a 'bolus' of a large amount of water is effective in distinguishing physiological from pathological 18F-FDG uptake in the GIT. Method: Over the past seven months, patients who were scanned and on review had FDG-avidity in the stomach, or had FDG-avidity of an uncertain aetiology further along the GIT, were selected for further scanning. Depending on the site of FDG uptake, patients were either given 1) 2 glasses of water on the bed immediately before scanning or 2) given 6-8 glasses of water in the space of an hour and a delay preceded before scanning over the GIT. Results: To date, 11 patients who have had 13 FDG PET/CT scans have had further water-enhanced delayed imaging. 8(61.5%) scans proved water to be a useful contrast agent. In 11(84.6%) cases, an appropriate amount and timing of water ingested assisted in further evaluating a specific region. In 7(53.9%) cases a large bolus of water allowed the reporting doctor to effectively distinguish between physiological and pathological uptake in the GIT. Conclusions: Patients with gastric/gastro-oesophageal/pancreatic cancers benefit from imaging with water in the stomach or small bowel. Scanning patients with discrete, FDG uptake in the large bowel following a large 'bolus' of water can help to distinguish physiological from pathological FDG uptake.

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

International Nuclear Information System (INIS)

Goerres, Gerhard W.; Hany, Thomas F.; Kamel, Ehab; Schulthess von, Gustav K.; Buck, Alfred

2002-01-01

Germanium-68 based attenuation correction (PET Ge68 ) 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 (PET CT ) 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 PET Ge68 and PET CT . Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PET CT in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PET Ge68 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 PET Ge68 and PET CT 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 68 Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the non-attenuation-corrected PET images also be

MR-assisted PET Motion Correction for eurological Studies in an Integrated MR-PET Scanner

Science.gov (United States)

Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B.; Michel, Christian J.; El Fakhri, Georges; Schmand, Matthias; Sorensen, A. Gregory

2011-01-01

Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MR data can be used for motion tracking. In this work, a novel data processing and rigid-body motion correction (MC) algorithm for the MR-compatible BrainPET prototype scanner is described and proof-of-principle phantom and human studies are presented. Methods To account for motion, the PET prompts and randoms coincidences as well as the sensitivity data are processed in the line or response (LOR) space according to the MR-derived motion estimates. After sinogram space rebinning, the corrected data are summed and the motion corrected PET volume is reconstructed from these sinograms and the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed and motion estimates were obtained using two high temporal resolution MR-based motion tracking techniques. Results After accounting for the physical mismatch between the two scanners, perfectly co-registered MR and PET volumes are reproducibly obtained. The MR output gates inserted in to the PET list-mode allow the temporal correlation of the two data sets within 0.2 s. The Hoffman phantom volume reconstructed processing the PET data in the LOR space was similar to the one obtained processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the novel MC algorithm. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 seconds and 20 ms, respectively. Substantially improved PET images with excellent delineation of specific brain structures were obtained after applying the MC using these MR-based estimates. Conclusion A novel MR-based MC

Comparison of 18F-FDG PET/CT and PET/MRI in patients with multiple myeloma

OpenAIRE

Sachpekidis, Christos; Hillengass, Jens; Goldschmidt, Hartmut; Mosebach, Jennifer; Pan, Leyun; Schlemmer, Heinz-Peter; Haberkorn, Uwe; Dimitrakopoulou-Strauss, Antonia

2015-01-01

PET/MRI represents a promising hybrid imaging modality with several potential clinical applications. Although PET/MRI seems highly attractive in the diagnostic approach of multiple myeloma (MM), its role has not yet been evaluated. The aims of this prospective study are to evaluate the feasibility of 18F-FDG PET/MRI in detection of MM lesions, and to investigate the reproducibility of bone marrow lesions detection and quantitative data of 18F-FDG uptake between the functional (PET) component ...

Influence of content and particle size of waste pet bottles on concrete behavior at different w/c ratios

International Nuclear Information System (INIS)

Albano, C.; Camacho, N.; Hernandez, M.; Matheus, A.; Gutierrez, A.

2009-01-01

The goal of this work was to study the mechanical behavior of concrete with recycled Polyethylene Therephtalate (PET), varying the water/cement ratio (0.50 and 0.60), PET content (10 and 20 vol%) and the particle size. Also, the influence of the thermal degradation of PET in the concrete was studied, when the blends were exposed to different temperatures (200, 400, 600 o C). Results indicate that PET-filled concrete, when volume proportion and particle size of PET increased, showed a decrease in compressive strength, splitting tensile strength, modulus of elasticity and ultrasonic pulse velocity; however, the water absorption increased. On the other hand, the flexural strength of concrete-PET when exposed to a heat source was strongly dependent on the temperature, water/cement ratio, as well as on the PET content and particle size. Moreover, the activation energy was affected by the temperature, PET particles location on the slabs and water/cement ratio.

Influence of content and particle size of waste pet bottles on concrete behavior at different w/c ratios.

Science.gov (United States)

Albano, C; Camacho, N; Hernández, M; Matheus, A; Gutiérrez, A

2009-10-01

The goal of this work was to study the mechanical behavior of concrete with recycled Polyethylene Therephtalate (PET), varying the water/cement ratio (0.50 and 0.60), PET content (10 and 20 vol%) and the particle size. Also, the influence of the thermal degradation of PET in the concrete was studied, when the blends were exposed to different temperatures (200, 400, 600 degrees C). Results indicate that PET-filled concrete, when volume proportion and particle size of PET increased, showed a decrease in compressive strength, splitting tensile strength, modulus of elasticity and ultrasonic pulse velocity; however, the water absorption increased. On the other hand, the flexural strength of concrete-PET when exposed to a heat source was strongly dependent on the temperature, water/cement ratio, as well as on the PET content and particle size. Moreover, the activation energy was affected by the temperature, PET particles location on the slabs and water/cement ratio.

High resolution reconstruction of PET images using the iterative OSEM algorithm

International Nuclear Information System (INIS)

Doll, J.; Bublitz, O.; Werling, A.; Haberkorn, U.; Semmler, W.; Adam, L.E.; Pennsylvania Univ., Philadelphia, PA; Brix, G.

2004-01-01

Aim: Improvement of the spatial resolution in positron emission tomography (PET) by incorporation of the image-forming characteristics of the scanner into the process of iterative image reconstruction. Methods: All measurements were performed at the whole-body PET system ECAT EXACT HR + in 3D mode. The acquired 3D sinograms were sorted into 2D sinograms by means of the Fourier rebinning (FORE) algorithm, which allows the usage of 2D algorithms for image reconstruction. The scanner characteristics were described by a spatially variant line-spread function (LSF), which was determined from activated copper-64 line sources. This information was used to model the physical degradation processes in PET measurements during the course of 2D image reconstruction with the iterative OSEM algorithm. To assess the performance of the high-resolution OSEM algorithm, phantom measurements performed at a cylinder phantom, the hotspot Jaszczack phantom, and the 3D Hoffmann brain phantom as well as different patient examinations were analyzed. Results: Scanner characteristics could be described by a Gaussian-shaped LSF with a full-width at half-maximum increasing from 4.8 mm at the center to 5.5 mm at a radial distance of 10.5 cm. Incorporation of the LSF into the iteration formula resulted in a markedly improved resolution of 3.0 and 3.5 mm, respectively. The evaluation of phantom and patient studies showed that the high-resolution OSEM algorithm not only lead to a better contrast resolution in the reconstructed activity distributions but also to an improved accuracy in the quantification of activity concentrations in small structures without leading to an amplification of image noise or even the occurrence of image artifacts. Conclusion: The spatial and contrast resolution of PET scans can markedly be improved by the presented image restauration algorithm, which is of special interest for the examination of both patients with brain disorders and small animals. (orig.)

Comparison of PET/CT with Sequential PET/MRI Using an MR-Compatible Mobile PET System.

Science.gov (United States)

Nakamoto, Ryusuke; Nakamoto, Yuji; Ishimori, Takayoshi; Fushimi, Yasutaka; Kido, Aki; Togashi, Kaori

2018-05-01

The current study tested a newly developed flexible PET (fxPET) scanner prototype. This fxPET system involves dual arc-shaped detectors based on silicon photomultipliers that are designed to fit existing MRI devices, allowing us to obtain fused PET and MR images by sequential PET and MR scanning. This prospective study sought to evaluate the image quality, lesion detection rate, and quantitative values of fxPET in comparison with conventional whole-body (WB) PET and to assess the accuracy of registration. Methods: Seventeen patients with suspected or known malignant tumors were analyzed. Approximately 1 h after intravenous injection of 18 F-FDG, WB PET/CT was performed, followed by fxPET and MRI. For reconstruction of fxPET images, MRI-based attenuation correction was applied. The quality of fxPET images was visually assessed, and the number of detected lesions was compared between the 2 imaging methods. SUV max and maximum average SUV within a 1 cm 3 spheric volume (SUV peak ) of lesions were also compared. In addition, the magnitude of misregistration between fxPET and MR images was evaluated. Results: The image quality of fxPET was acceptable for diagnosis of malignant tumors. There was no significant difference in detectability of malignant lesions between fxPET and WB PET ( P > 0.05). However, the fxPET system did not exhibit superior performance to the WB PET system. There were strong positive correlations between the 2 imaging modalities in SUV max (ρ = 0.88) and SUV peak (ρ = 0.81). SUV max and SUV peak measured with fxPET were approximately 1.1-fold greater than measured with WB PET. The average misregistration between fxPET and MR images was 5.5 ± 3.4 mm. Conclusion: Our preliminary data indicate that running an fxPET scanner near an existing MRI system provides visually and quantitatively acceptable fused PET/MR images for diagnosis of malignant lesions. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

PET/CT: underlying physics, instrumentation, and advances.

Science.gov (United States)

Torres Espallardo, I

Since it was first introduced, the main goal of PET/CT has been to provide both PET and CT images with high clinical quality and to present them to radiologists and specialists in nuclear medicine as a fused, perfectly aligned image. The use of fused PET and CT images quickly became routine in clinical practice, showing the great potential of these hybrid scanners. Thanks to this success, manufacturers have gone beyond considering CT as a mere attenuation corrector for PET, concentrating instead on design high performance PET and CT scanners with more interesting features. Since the first commercial PET/CT scanner became available in 2001, both the PET component and the CT component have improved immensely. In the case of PET, faster scintillation crystals with high stopping power such as LYSO crystals have enabled more sensitive devices to be built, making it possible to reduce the number of undesired coincidence events and to use time of flight (TOF) techniques. All these advances have improved lesion detection, especially in situations with very noisy backgrounds. Iterative reconstruction methods, together with the corrections carried out during the reconstruction and the use of the point-spread function, have improved image quality. In parallel, CT instrumentation has also improved significantly, and 64- and 128-row detectors have been incorporated into the most modern PET/CT scanners. This makes it possible to obtain high quality diagnostic anatomic images in a few seconds that both enable the correction of PET attenuation and provide information for diagnosis. Furthermore, nowadays nearly all PET/CT scanners have a system that modulates the dose of radiation that the patient is exposed to in the CT study in function of the region scanned. This article reviews the underlying physics of PET and CT imaging separately, describes the changes in the instrumentation and standard protocols in a combined PET/CT system, and finally points out the most important

Diagnostic performance of FDG PET or PET/CT in prosthetic infection after arthroplasty: a meta-analysis

International Nuclear Information System (INIS)

Jin, H.; Yuan, L.; Li, C.; Kan, Y.; Yang, J.; Hao, R.

2014-01-01

The purpose of this study was to systematically review and perform a meta-analysis of published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty. A comprehensive computer literature search of studies published through May 31, 2012 regarding PET or PET/CT in patients suspicious of prosthetic infection was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of PET or PET/CT in patients with suspicious of prosthetic infection. Fourteen studies comprising 838 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 86% (95% confidence interval [CI] 82-90%) on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 86% (95% CI 83-89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.93 on a per prosthesis-based analysis. In patients suspicious of prosthetic infection, FDG PET or PET/CT demonstrated high sensitivity and specificity. FDG PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false positive results and influcing factors should kept in mind.

Diagnostic performance of FDG PET or PET/CT in prosthetic infection after arthroplasty: a meta-analysis.

Science.gov (United States)

Jin, H; Yuan, L; Li, C; Kan, Y; Hao, R; Yang, J

2014-03-01

The purpose of this study was to systematically review and perform a meta-analysis of published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty. A comprehensive computer literature search of studies published through May 31, 2012 regarding PET or PET/CT in patients suspicious of prosthetic infection was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of PET or PET/CT in patients with suspicious of prosthetic infection. Fourteen studies comprising 838 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 86% (95% confidence interval [CI] 82-90%) on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 86% (95% CI 83-89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.93 on a per prosthesis-based analysis. In patients suspicious of prosthetic infection, FDG PET or PET/CT demonstrated high sensitivity and specificity. FDG PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false positive results and influcing factors should kept in mind.

{sup 90}Y -PET imaging: Exploring limitations and accuracy under conditions of low counts and high random fraction

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Carlier, Thomas, E-mail: thomas.carlier@chu-nantes.fr [Department of Nuclear Medicine, University Hospital of Nantes, Place Alexis Ricordeau, Nantes 44093, France and CRCNA–UMR 892 INSERM 6299 CNRS, 8 quai Moncousu BP 70721, Nantes 44007 (France); Willowson, Kathy P. [Institute of Medical Physics, University of Sydney, Camperdown, New South Wales 2006 (Australia); Fourkal, Eugene [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Bailey, Dale L. [Faculty of Health Sciences, University of Sydney, Lidcombe 2141, Australia and Department of Nuclear Medicine, Royal North Shore Hospital, St Leonards, New South Wales 2065 (Australia); Doss, Mohan [Department of Diagnostic Imaging, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States); Conti, Maurizio [Siemens Healthcare Molecular Imaging, 810 Innovation Drive, Knoxville, Tennessee 37932 (United States)

2015-07-15

Purpose: {sup 90}Y -positron emission tomography (PET) imaging is becoming a recognized modality for postinfusion quantitative assessment following radioembolization therapy. However, the extremely low counts and high random fraction associated with {sup 90}Y -PET may significantly impair both qualitative and quantitative results. The aim of this work was to study image quality and noise level in relation to the quantification and bias performance of two types of Siemens PET scanners when imaging {sup 90}Y and to compare experimental results with clinical data from two types of commercially available {sup 90}Y microspheres. Methods: Data were acquired on both Siemens Biograph TruePoint [non-time-of-flight (TOF)] and Biograph microcomputed tomography (mCT) (TOF) PET/CT scanners. The study was conducted in three phases. The first aimed to assess quantification and bias for different reconstruction methods according to random fraction and number of true counts in the scan. The NEMA 1994 PET phantom was filled with water with one cylindrical insert left empty (air) and the other filled with a solution of {sup 90}Y . The phantom was scanned for 60 min in the PET/CT scanner every one or two days. The second phase used the NEMA 2001 PET phantom to derive noise and image quality metrics. The spheres and the background were filled with a {sup 90}Y solution in an 8:1 contrast ratio and four 30 min acquisitions were performed over a one week period. Finally, 32 patient data (8 treated with Therasphere{sup ®} and 24 with SIR-Spheres{sup ®}) were retrospectively reconstructed and activity in the whole field of view and the liver was compared to theoretical injected activity. Results: The contribution of both bremsstrahlung and LSO trues was found to be negligible, allowing data to be decay corrected to obtain correct quantification. In general, the recovered activity for all reconstruction methods was stable over the range studied, with a small bias appearing at extremely

A comparison of high dose Ga-67 SPECT and FDG PET imaging in malignant melanoma

International Nuclear Information System (INIS)

Kaliff, V.; Hicks, R.J.; Binns, D.S.; Henderson, M.A.; Ainslie, J.; Jenner, D.A.

1998-01-01

Full text: Ga-67 imaging for tumour localisation lost favour in the 1970's. With improvement in technology and use of higher doses, it has now found an important role in lymphoma. A similar phenomenon may be possible in the staging of melanoma. This study therefore compares high dose (370 MBq) Ga-67 imaging using a day 5 and 7 whole-body and comprehensive SPECT protocol, with (100 MBq) F-18 fluorodeoxyglucose (FDG) imaging using positron emission tomography (PET): a technique recently shown to be highly accurate in this condition. 85 patients; 46 males, mean age 52+17 yrs: range 22-83 yrs, underwent both studies within 9±16 days (max-91 days). Scans were judged as positive (+ve), negative (-ve) or equivocal (EQ) for local, regional and distant disease. Clinical follow-up resolved discordant scan findings. PET and Ga-67 results were concordant in 61 (70%) patients (19 with +ve, 37 -ve and 5 EQ scans). None of the 9 ps with one EQ and one eye scan had disease on follow-up. Follow-up was available in 4/5 patients with discordantly +ve (3 patients) or more extensive Ga-67 abnormality: 3 patients had disease confirmed, 1 patient false +ve (asymmetric lung hilum). Follow-up was available in 9/10 patients with discordantly +ve (3 patients) or more extensive PET abnormality: 4 patients had confirmed disease, l pt false +ve (bladder diverticulum). A further 4 patients had second primaries (2 rectal carcinomas, 1 plasmacytoma, 1 basal cell carcinoma). High dose Ga-67 scanning incorporating SPECT appears to be a reasonable alternative to FDG PET for screening patients with melanoma. In this series PET's main advantages were in the detection of other occult tumours, greater patient convenience and lower radiation dosimetry

Evaluation of 19 cases of benign lesions with high accumulation of tracer on 18F-FDG PET imaging

International Nuclear Information System (INIS)

Wang Quanshi; Wu Hubing; Wang Mingfang; Huang Zuhan

2003-01-01

Objective: To review PET images of benign lesions with high accumulation of 18 F-FDG and to analyse the possibility of FDG PET imaging for differentiating the benign from the malignant. Methods: 18 F-FDG PET imaging was performed on 19 patients with benign diseases including 13 cases of active tuberculosis and 6 cases of other benign diseases. Positive pathologic or bacteriological results were obtained for all the patients. PET images were evaluated with standardized uptake value (SUV), lesion shapes , and radioactivity distribution. CT or MRI and histopathologic findings also were reviewed. Results: 1) Thirteen patients with active tuberculosis showed high uptake of 18 F-FDG. The SUV was 3.1±1.8. But radioactivity distribution in some lesions was not uniform and there were defect areas in the lesions. Histopathologic findings proved that the defect areas were induced by caseous necrosis. Seven cases of pulmonary tuberculosis showed two or multiple stripe and funicular high accumulation and other lesions displayed high uptake in sheet or irregular shape; 1 case of scrofula and 1 case of splenetic tuberculosis showed defect areas in the lesions; the other scrofula case showed focal intense uptake. Two of lumbar tuberculosis showed intense uptake in the lumbar vertebra, and one of the two cases complicated with the cold abscess showed bilateral high accumulation in the shape of sheet along musculus psoas major. In the peritoneal tuberculosis case, PET images showed diffuse incrassation and intense uptake in peritoneum and mesentery. CT findings revealed that the peritoneum and mesentery thickened. 2) Pulmonary abscess, pulmonary cryptococcus granuloma, cerebral cryptococcus granuloma, pulmonary inflammatory pseudotumor, leiomyoma, and breast adenoma all showed high accumulation in the shapes of nodule or mass. Mean SUV was 4.5±3.1. CT or MRI findings were the same as on PET images shape. Histopathologic work-up did not find necrosis in the lesions. Conclusions

Effects on Mechanical Properties of Recycled PET in Cement-Based Composites

Directory of Open Access Journals (Sweden)

Liliana Ávila Córdoba

2013-01-01

Full Text Available Concretes consisting of portland cement (OPC, silica sand, gravel, water, and recycled PET particles were developed. Specimens without PET particles were prepared for comparison. Curing times, PET particle sizes, and aggregate concentrations were varied. The compressive strength, compressive strain at yield point, and Young modulus were determined. Morphological and chemical compositions of recycled PET particles were seen in a scanning electron microscopy. Results show that smaller PET particle sizes in lower concentrations generate improvements on compressive strength and strain, and Young’s modulus decreases when the size of PET particles used was increased.

Comparison between PET/MR and PET/CT in evaluation of oncological patients%PET/MR与PET/CT的对比研究

Institute of Scientific and Technical Information of China (English)

徐白萱; 富丽萍; 关志伟; 尹大一; 刘家金; 杨晖; 张锦明; 陈英茂; 安宁豫

2014-01-01

Objective To verify the feasibility of the integrated PET/MR for oncological applications by comparing PET/MR with PET/CT in terms of lesion detection and quantitative measurement.Methods A total of 277 patients (165 males,112 females,average age (52.9± 12.6) years) voluntarily participated in this same-day PET/CT and PET/MR comparative study.The time interval between the two studies was 15-35 min.PET/CT images were acquired and reconstructed following standard protocols.PET/MR covered the body trunk with a sequence combination of transverse T1 weighted imaging (WI) 3D-volumetric interpolated breath-hold,T2WI turbo spin echo with fat saturation,diffusion-weighted imaging,and simultaneous PET acquisition.PET images were reconstructed by vender-provided attenuation correction methods.The results of PET/CT and PET/MR were regarded as positive if any modality (CT,PET or MRI) was positive.SUVmax was obtained by the manually drawn ROI.Detection rates were compared with x2 test and SUVmax from the two modalities was analyzed with Spearman correlation analysis.Results A total of 353 lesions were detected in 220 patients.Compared to PET/CT,PET/MR revealed 30 additional true-positive lesions,while missed 6.The detection rates between PET/CT and PET/MR were significantly different (P＜0.05).The lesion-based and patient-based consistency was 89.8％ (317/353) and 85.9％ (189/220),respectively.There were significant correlations of SUVmax between PET/MR and PET/CT for lesions(rs =0.91,P＜0.01) and for normal tissues(rs =0.62-0.76,all P＜0.01).Conclusions With reference to PET/CT,integrated PET/MR may provide comparable semi-quantitative measurements of pathological lesions as well as normal tissues.Integrated PET/MR may be more effective to detect lesions in abdomen and pelvis.%目的 通过与PET/CT在病灶检测及定量分析方面的比较,论证PET/MR一体机应用于临床的可行性.方法 2012年5月至2013年2月共300例患者同天间隔15 ～ 35 min行PET/CT和PET

'Serial review on clinical PET tracers'. Application of health insurance of [15O]oxygen PET and [18F]FDG-PET

International Nuclear Information System (INIS)

Torizuka, Kanji

2009-01-01

As regards the application required for health insurance of PET, the Ministry of Health, Labour and Welfare indicates the following procedures: first, request a permission to the Ministry of Health, Labour and Welfare for the clinical use of the automatic synthetic instrument for PET drug, approved according to the Pharmaceutical Affairs Law. Second, put into practice the use of PET test, under the highly advanced medicine premises. Then, in case of gathered positive results, the health insurance is approved for this PET test. Thus, following the above mentioned procedures, first, the use of [ 15 O] oxygen PET was approved in April 1996. Second, the use of [ 18 F]FDG-PET was approved in 12 different diseases: epilepsy, ischemic heart disease and 10 different types of cancer, in April 2002. Third, in April 2006, a additional 3 types of cancer were approved. Now, we are in the process to get the health insurance of all kinds of malignant tumors (cancer and sarcoma) except for the early gastric cancer. (author)

[{sup 18}F]FDG PET/CT outperforms [{sup 18}F]FDG PET/MRI in differentiated thyroid cancer

Energy Technology Data Exchange (ETDEWEB)

Vrachimis, Alexis; Wenning, Christian; Weckesser, Matthias; Stegger, Lars [University Hospital Muenster, Department of Nuclear Medicine, Muenster (Germany); Burg, Matthias Christian; Allkemper, Thomas [University Hospital Muenster, Department of Clinical Radiology, Muenster (Germany); Schaefers, Michael [University Hospital Muenster, Department of Nuclear Medicine, Muenster (Germany); Westfaelische Wilhelms University Muenster, European Institute for Molecular Imaging, Muenster (Germany)

2016-02-15

To evaluate the diagnostic potential of PET/MRI with [{sup 18}F]FDG in comparison to PET/CT in patients with differentiated thyroid cancer suspected or known to have dedifferentiated. The study included 31 thyroidectomized and remnant-ablated patients who underwent a scheduled [{sup 18}F]FDG PET/CT scan and were then enrolled for a PET/MRI scan of the neck and thorax. The datasets (PET/CT, PET/MRI) were rated regarding lesion count, conspicuity, diameter and characterization. Standardized uptake values were determined for all [{sup 18}F]FDG-positive lesions. Histology, cytology, and examinations before and after treatment served as the standards of reference. Of 26 patients with a dedifferentiated tumour burden, 25 were correctly identified by both [{sup 18}F]FDG PET/CT and PET/MRI. Detection rates by PET/CT and PET/MRI were 97 % (113 of 116 lesions) and 85 % (99 of 113 lesions) for malignant lesions, and 100 % (48 of 48 lesions) and 77 % (37 of 48 lesions) for benign lesions, respectively. Lesion conspicuity was higher on PET/CT for both malignant and benign pulmonary lesions and in the overall rating for malignant lesions (p < 0.001). There was a difference between PET/CT and PET/MRI in overall evaluation of malignant lesions (p < 0.01) and detection of pulmonary metastases (p < 0.001). Surgical evaluation revealed three malignant lesions missed by both modalities. PET/MRI additionally failed to detect 14 pulmonary metastases and 11 benign lesions. In patients with thyroid cancer and suspected or known dedifferentiation, [{sup 18}F]FDG PET/MRI was inferior to low-dose [{sup 18}F]FDG PET/CT for the assessment of pulmonary status. However, for the assessment of cervical status, [{sup 18}F]FDG PET/MRI was equal to contrast-enhanced neck [{sup 18}F]FDG PET/CT. Therefore, [{sup 18}F]FDG PET/MRI combined with a low-dose CT scan of the thorax may provide an imaging solution when high-quality imaging is needed and high-energy CT is undesirable or the use of a contrast

MRPC-PET: A new technique for high precision time and position measurements

International Nuclear Information System (INIS)

Doroud, K.; Hatzifotiadou, D.; Li, S.; Williams, M.C.S.; Zichichi, A.; Zuyeuski, R.

2011-01-01

The purpose of this paper is to consider a new technology for medical diagnosis: the MRPC-PET. This technology allows excellent time resolution together with 2-D position information thus providing a fundamental step in this field. The principle of this method is based on the Multigap Resistive Plate Chamber (MRPC) capable of high precision time measurements. We have previously found that the route to precise timing is differential readout (this requires matching anode and cathode strips); thus crossed strip readout schemes traditionally used for 2-D readout cannot be exploited. In this paper we consider the time difference from the two ends of the strip to provide a high precision measurement along the strip; the average time gives precise timing. The MRPC-PET thus provides a basic step in the field of medical technology: excellent time resolution together with 2-D position measurement.

Hybrid imaging for detection of carcinoma of unknown primary: A preliminary comparison trial of whole-body PET/MRI versus PET/CT

International Nuclear Information System (INIS)

Ruhlmann, Verena; Ruhlmann, Marcus; Bellendorf, Alexander; Grueneisen, Johannes; Sawicki, Lino M.; Grafe, Hong; Forsting, Michael; Bockisch, Andreas; Umutlu, Lale

2016-01-01

Highlights: • Both 18F-FDG PET/CT and 18F-FDG PET/MRI provide a comparable diagnostic ability for detection of primary cancer and metastases in CUP-syndrome. • Both imaging methods showed comparably high lesion conspicuity and diagnostic confidence (superior assessment of cervical lesions in PET/MRI). • PET/MRI may serve as a powerful alternative, particularly for therapy monitoring or surveillance considering the long-term cumulative dose. - Abstract: Purpose: The aim of this study is to evaluate and compare the diagnostic potential of integrated whole-body [18F]FDG-PET/MRI to [18F]FDG-PET/CT for detection of a potential primary cancer and metastases in patients suspected for cancer of unknown primary (CUP). Methods: A total of 20 patients (15 male, 5 female, age 53 ± 13 years) suspect for CUP underwent a dedicated head and neck & whole-body [18F]FDG-PET/CT (Biograph mCT 128, Siemens Healthcare) and a subsequent simultaneous [18F]FDG-PET/MRI examination (Biograph mMR, Siemens Healthcare). Two readers rated the datasets (PET/CT; PET/MRI) regarding the detection of the primary cancer and metastases, lesion conspicuity (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale). PET analysis comprised the assessment of maximum standardized uptake values (SUVmax) of all PET-positive lesions using volume of interest (VOI) analysis derived from the PET/CT and PET/MR datasets. All available data considering histology and imaging including prior and clinical follow-up examinations served as reference standard. Statistical analysis included comparison of mean values using Mann-Whitney U test and correlation of SUVmax using Pearson‘s correlation. Results: In 14 out of 20 patients 49 malignant lesions were present. The primary cancer could be correctly identified in 11/20 patients with both PET/CT and PET/MRI. PET/CT enabled the detection of a total 38 metastases, PET/MR respectively of 37 metastases (one lung metastasis <5mm was missed). PET/CT and

Hybrid imaging for detection of carcinoma of unknown primary: A preliminary comparison trial of whole-body PET/MRI versus PET/CT

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Ruhlmann, Verena; Ruhlmann, Marcus; Bellendorf, Alexander [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Grueneisen, Johannes [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Sawicki, Lino M. [Department of Diagnostic and Interventional Radiology, University of Dusseldorf, Moorenstraße 5, 40225 Dusseldorf (Germany); Grafe, Hong [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Forsting, Michael [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Bockisch, Andreas [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Umutlu, Lale, E-mail: verena.ruhlmann@uk-essen.de [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany)

2016-11-15

Highlights: • Both 18F-FDG PET/CT and 18F-FDG PET/MRI provide a comparable diagnostic ability for detection of primary cancer and metastases in CUP-syndrome. • Both imaging methods showed comparably high lesion conspicuity and diagnostic confidence (superior assessment of cervical lesions in PET/MRI). • PET/MRI may serve as a powerful alternative, particularly for therapy monitoring or surveillance considering the long-term cumulative dose. - Abstract: Purpose: The aim of this study is to evaluate and compare the diagnostic potential of integrated whole-body [18F]FDG-PET/MRI to [18F]FDG-PET/CT for detection of a potential primary cancer and metastases in patients suspected for cancer of unknown primary (CUP). Methods: A total of 20 patients (15 male, 5 female, age 53 ± 13 years) suspect for CUP underwent a dedicated head and neck & whole-body [18F]FDG-PET/CT (Biograph mCT 128, Siemens Healthcare) and a subsequent simultaneous [18F]FDG-PET/MRI examination (Biograph mMR, Siemens Healthcare). Two readers rated the datasets (PET/CT; PET/MRI) regarding the detection of the primary cancer and metastases, lesion conspicuity (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale). PET analysis comprised the assessment of maximum standardized uptake values (SUVmax) of all PET-positive lesions using volume of interest (VOI) analysis derived from the PET/CT and PET/MR datasets. All available data considering histology and imaging including prior and clinical follow-up examinations served as reference standard. Statistical analysis included comparison of mean values using Mann-Whitney U test and correlation of SUVmax using Pearson‘s correlation. Results: In 14 out of 20 patients 49 malignant lesions were present. The primary cancer could be correctly identified in 11/20 patients with both PET/CT and PET/MRI. PET/CT enabled the detection of a total 38 metastases, PET/MR respectively of 37 metastases (one lung metastasis <5mm was missed). PET/CT and

Imaging with 124I in differentiated thyroid carcinoma: is PET/MRI superior to PET/CT?

International Nuclear Information System (INIS)

Binse, I.; Poeppel, T.D.; Ruhlmann, M.; Gomez, B.; Bockisch, A.; Rosenbaum-Krumme, S.J.; Umutlu, L.

2016-01-01

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 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 2 ) followed by PET/MRI of the neck 24 h after 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 2 acquisition time (2 min, PET/MRI 2 ) and the other covering the whole MRI scan time (30 min, PET/MRI 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 2 detected significantly more iodine-positive metastases and thyroid remnants than PET/CT 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 30 tended to detect more PET-positive metastases than PET/MRI 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-positive lesions as either metastasis or thyroid remnant

Pet Problems at Home: Pet Problems in the Community.

Science.gov (United States)

Soltow, Willow

1984-01-01

Discusses problems of pets in the community, examining the community's role related to disruptive pets and pet overpopulation. Also discusses pet problems at home, offering advice on selecting a pet, meeting a pet's needs, and disciplining pets. Includes a list of books, films/filmstrips, teaching materials, and various instructional strategies.…

Evacuating People and Their Pets: Older Floridians' Need for and Proximity to Pet-Friendly Shelters.

Science.gov (United States)

Douglas, Rachel; Kocatepe, Ayberk; Barrett, Anne E; Ozguven, Eren Erman; Gumber, Clayton

2017-10-04

Pets influence evacuation decisions, but little is known about pet-friendly emergency shelters' availability or older adults' need for them. Our study addresses this issue, focusing on the most densely populated area of Florida (Miami-Dade)-the state with the oldest population and greatest hurricane susceptibility. We use Geographic Information Systems (GIS)-based methodology to identify the shortest paths to pet-friendly shelters, based on distance and congested and uncongested travel times-taking into account the older population's spatial distribution. Logistic regression models using the 2013 American Housing Survey's Disaster Planning Module examine anticipated shelter use as a function of pet ownership and requiring pet evacuation assistance. Thirty-four percent of older adults in the Miami-Dade area have pets-35% of whom report needing pet evacuation assistance. However, GIS accessibility measures show that travel time factors are likely to impede older adults' use of the area's few pet-friendly shelters. Logistic regression results reveal that pet owners are less likely to report anticipating shelter use; however, the opposite holds for pet owners reporting they would need help evacuating their pets-they anticipate using shelters. High pet shelter need coupled with low availability exacerbates older adults' heightened vulnerability during Florida's hurricane season. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The role of PET quantification in cardiovascular imaging.

Science.gov (United States)

Slomka, Piotr; Berman, Daniel S; Alexanderson, Erick; Germano, Guido

2014-08-01

Positron Emission Tomography (PET) has several clinical and research applications in cardiovascular imaging. Myocardial perfusion imaging with PET allows accurate global and regional measurements of myocardial perfusion, myocardial blood flow and function at stress and rest in one exam. Simultaneous assessment of function and perfusion by PET with quantitative software is currently the routine practice. Combination of ejection fraction reserve with perfusion information may improve the identification of severe disease. The myocardial viability can be estimated by quantitative comparison of fluorodeoxyglucose ( 18 FDG) and rest perfusion imaging. The myocardial blood flow and coronary flow reserve measurements are becoming routinely included in the clinical assessment due to enhanced dynamic imaging capabilities of the latest PET/CT scanners. Absolute flow measurements allow evaluation of the coronary microvascular dysfunction and provide additional prognostic and diagnostic information for coronary disease. Standard quantitative approaches to compute myocardial blood flow from kinetic PET data in automated and rapid fashion have been developed for 13 N-ammonia, 15 O-water and 82 Rb radiotracers. The agreement between software methods available for such analysis is excellent. Relative quantification of 82 Rb PET myocardial perfusion, based on comparisons to normal databases, demonstrates high performance for the detection of obstructive coronary disease. New tracers, such as 18 F-flurpiridaz may allow further improvements in the disease detection. Computerized analysis of perfusion at stress and rest reduces the variability of the assessment as compared to visual analysis. PET quantification can be enhanced by precise coregistration with CT angiography. In emerging clinical applications, the potential to identify vulnerable plaques by quantification of atherosclerotic plaque uptake of 18 FDG and 18 F-sodium fluoride tracers in carotids, aorta and coronary arteries

Interference between PET and MRI sub-systems in a silicon-photomultiplier-based PET/MRI system

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Watabe, Hiroshi; Kanai, Yasukazu; Hatazawa, Jun; Aoki, Masaaki; Sugiyama, Eiji; Watabe, Tadashi; Imaizumi, Masao; Shimosegawa, Eku

2011-01-01

The silicon-photomultiplier (Si-PM) is a promising photodetector, especially for integrated PET/MRI systems, due to its small size, high gain, and low sensitivity to static magnetic fields. The major problem using a Si-PM-based PET system within the MRI system is the interference between the PET and MRI units. We measured the interference by combining a Si-PM-based PET system with a permanent-magnet MRI system. When the RF signal-induced pulse height exceeded the lower energy threshold level of the PET system, interference between the Si-PM-based PET system and MRI system was detected. The prompt as well as the delayed coincidence count rates of the Si-PM-based PET system increased significantly. These noise counts produced severe artifacts on the reconstructed images of the Si-PM-based PET system. In terms of the effect of the Si-PM-based PET system on the MRI system, although no susceptibility artifact was observed on the MR images, electronic noise from the PET detector ring was detected by the RF coil and reduced the signal-to-noise ratio (S/N) of the MR images. The S/N degradation of the MR images was reduced when the distance between the RF coil and the Si-PM-based PET system was increased. We conclude that reducing the interference between the PET and MRI systems is essential for achieving the optimum performance of integrated Si-PM PET/MRI systems.

Evaluation of compressive strength and water absorption of soil-cement bricks manufactured with addition of pet (polyethylene terephthalate wastes

Directory of Open Access Journals (Sweden)

João Alexandre Paschoalin Filho

2016-04-01

Full Text Available This paper presents the evaluation of compressive strength of soil-cement bricks obtained by the inclusion in their mixture of PET flakes through mineral water bottles grinding. The Polyethylene Terephthalate (PET has been characterized by its difficulty of disaggregation in nature, requiring a long period for this. On the other hand, with the increase in civil construction activities the demand for raw material also increases, causing considerable environmental impacts. In this context, the objective of this research is to propose a simple methodology, preventing its dumping and accumulation in irregular areas, and reducing the demand of raw materials by the civil construction industry. The results showed that compressive strengths obtained were lower than recommended by NBR 8491 (Associação Brasileira de Normas Técnicas [ABNT], 2012b at seven days of curing time. However, they may be used as an alternative solution in masonry works in order to not submit themselves to great loads or structural functions. The studied bricks also presented water absorption near to recommended values by NBR 8491 (ABNT, 2012b. Manufacturing costs were also determined for this brick, comparing it with the costs of other brick types. Each brick withdrew from circulation approximately 300 g of PET waste. Thus, for an area of 1 m2 the studied bricks can promote the withdrawal of approximately 180 beverage bottles of 2 L capacity.

High impact of FDG-PET/CT in diagnostic strategies for ovarian cancer

International Nuclear Information System (INIS)

Zytoon, Ashraf Anas; Murakami, Koji; Eid, Hazem; El-Gammal, Mahmoud

2013-01-01

Background: Ovarian cancer has the highest mortality of all gynecologic malignancies. FDG-PET/CT was proven to be accurate for identification of primary ovarian tumors, regional lymph nodes, and distant metastases. Purpose: To evaluate ovarian masses at FDG-PET/CT in correlation with histopathologic findings. Material and Methods: Ninety-eight patients underwent whole body FDG-PET/CT examination. Eighty-six patients with primary ovarian cancer and 12 patients with metastatic disease to the ovaries were included. Results: PET/CT imaging was true-positive in 87/94 patients with malignant tumors. In 4/4 patients with benign tumors, PET/CT results were true-negative, with sensitivity of 92.6%, specificity 100%, total test accuracy 92.9%. Fifty-seven patients were diagnosed as stage IV ovarian cancer with distant metastasis. Conclusion: The anatomical/functional examination by FDG-PET/CT was proven to be valuable in increasing the diagnostic accuracy that can help improve patient management

The relationship between myocardial blood flow and myocardial viability after reperfusion. Myocardial viability assessed by 15O-water-PET

International Nuclear Information System (INIS)

Tsukagoshi, Joichi

1994-01-01

The purpose of this study was to examine the relationship between myocardial blood flow and myocardial viability in the ischemic canine myocardium after reperfusion. Transient ischemia was induced by 60-, 90-, and 180-minute occlusion of the left anterior descending coronary artery. Myocardial blood flow (MBF) was measured in the areas in which regional contractility was severely impaired (ehocardiographically akinetic or dyskinetic) in the early reperfusion period by 15 O-water positron emission tomography (PET) 12 hours and 4 weeks after reperfusion. An MBF ratio of ischemic to nonischemic regions 12 hours after reperfusion was inversely correlated with the amount of histologically determined tissue necrosis (r=-0.74). The regional contractility recovered 4 weeks later in the areas where an MBF ratio was 0.48 or greater, but did not recover in the areas with a lower MBF ratio. Thus, myocardial viability can be appropriately predicted in the early phase of myocardial perfusion by PET with 15 O-water even in the absence of metabolic imaging. (author)

Automatic extraction of forward stroke volume using dynamic PET/CT

DEFF Research Database (Denmark)

Harms, Hans; Tolbod, Lars Poulsen; Hansson, Nils Henrik

Background: Dynamic PET can be used to extract forward stroke volume (FSV) by the indicator dilution principle. The technique employed can be automated and is in theory independent on the tracer used and may therefore be added to any dynamic cardiac PET protocol. The aim of this study...... was to validate automated methods for extracting FSV directly from dynamic PET studies for two different tracers and to examine potential scanner hardware bias. Methods: 21 subjects underwent a dynamic 27 min 11C-acetate PET scan on a Siemens Biograph TruePoint 64 PET/CT scanner (scanner I). In addition, 8...... subjects underwent a dynamic 6 min 15O-water PET scan followed by a 27 min 11C-acetate PET scan on a GE Discovery ST PET/CT scanner (scanner II). The LV-aortic time-activity curve (TAC) was extracted automatically from dynamic PET data using cluster analysis. The first-pass peak was isolated by automatic...

Feasibility of proton-activated implantable markers for proton range verification using PET

Science.gov (United States)

Cho, Jongmin; Ibbott, Geoffrey; Gillin, Michael; Gonzalez-Lepera, Carlos; Titt, Uwe; Paganetti, Harald; Kerr, Matthew; Mawlawi, Osama

2013-11-01

Proton beam range verification using positron emission tomography (PET) currently relies on proton activation of tissue, the products of which decay with a short half-life and necessitate an on-site PET scanner. Tissue activation is, however, negligible near the distal dose fall-off region of the proton beam range due to their high interaction energy thresholds. Therefore Monte Carlo simulation is often supplemented for comparison with measurement; however, this also may be associated with systematic and statistical uncertainties. Therefore, we sought to test the feasibility of using long-lived proton-activated external materials that are inserted or infused into the target volume for more accurate proton beam range verification that could be performed at an off-site PET scanner. We irradiated samples of ≥98% 18O-enriched water, natural Cu foils, and >97% 68Zn-enriched foils as candidate materials, along with samples of tissue-equivalent materials including 16O water, heptane (C7H16), and polycarbonate (C16H14O3)n, at four depths (ranging from 100% to 3% of center of modulation (COM) dose) along the distal fall-off of a modulated 160 MeV proton beam. Samples were irradiated either directly or after being embedded in Plastic Water® or balsa wood. We then measured the activity of the samples using PET imaging for 20 or 30 min after various delay times. Measured activities of candidate materials were up to 100 times greater than those of the tissue-equivalent materials at the four distal dose fall-off depths. The differences between candidate materials and tissue-equivalent materials became more apparent after longer delays between irradiation and PET imaging, due to the longer half-lives of the candidate materials. Furthermore, the activation of the candidate materials closely mimicked the distal dose fall-off with offsets of 1 to 2 mm. Also, signals from the foils were clearly visible compared to the background from the activated Plastic Water® and balsa wood

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests

OpenAIRE

Mustafa Demir; Türkay Toklu; Mohammad Abuqbeitah; Hüseyin Çetin; H. Sezer Sezgin; Nami Yeyin; Kerim Sönmezoğlu

2018-01-01

Objective: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. Methods: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated...

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests

OpenAIRE

Demir, Mustafa; Toklu, Türkay; Abuqbeitah, Mohammad; Çetin, Hüseyin; Sezgin, H. Sezer; Yeyin, Nami; Sönmezoğlu, Kerim

2018-01-01

Objective: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. Methods: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated asp...

Simulation study comparing the helmet-chin PET with a cylindrical PET of the same number of detectors

Science.gov (United States)

Ahmed, Abdella M.; Tashima, Hideaki; Yoshida, Eiji; Nishikido, Fumihiko; Yamaya, Taiga

2017-06-01

There is a growing interest in developing brain PET scanners with high sensitivity and high spatial resolution for early diagnosis of neurodegenerative diseases and studies of brain functions. Sensitivity of the PET scanner can be improved by increasing the solid angle. However, conventional PET scanners are designed based on a cylindrical geometry, which may not be the most efficient design for brain imaging in terms of the balance between sensitivity and cost. We proposed a dedicated brain PET scanner based on a hemispheric shape detector and a chin detector (referred to as the helmet-chin PET), which is designed to maximize the solid angle by increasing the number of lines-of-response in the hemisphere. The parallax error, which PET scanners with a large solid angle tend to have, can be suppressed by the use of depth-of-interaction detectors. In this study, we carry out a realistic evaluation of the helmet-chin PET using Monte Carlo simulation based on the 4-layer GSO detector which consists of a 16  ×  16  ×  4 array of crystals with dimensions of 2.8  ×  2.8  ×  7.5 mm3. The purpose of this simulation is to show the gain in imaging performance of the helmet-chin PET compared with the cylindrical PET using the same number of detectors in each configuration. The sensitivity of the helmet-chin PET evaluated with a cylindrical phantom has a significant increase, especially at the top of the (field-of-view) FOV. The peak-NECR of the helmet-chin PET is 1.4 times higher compared to the cylindrical PET. The helmet-chin PET provides relatively low noise images throughout the FOV compared to the cylindrical PET which exhibits enhanced noise at the peripheral regions. The results show the helmet-chin PET can significantly improve the sensitivity and reduce the noise in the reconstructed images.

Treatment response evaluation with 18F-FDG PET/CT and 18F-NaF PET/CT in multiple myeloma patients undergoing high-dose chemotherapy and autologous stem cell transplantation.

Science.gov (United States)

Sachpekidis, Christos; Hillengass, J; Goldschmidt, H; Wagner, B; Haberkorn, U; Kopka, K; Dimitrakopoulou-Strauss, A

2017-01-01

The aim of this study was to assess the combined use of the radiotracers 18 F-FDG and 18 F-NaF in treatment response evaluation of a group of multiple myeloma (MM) patients undergoing high-dose chemotherapy (HDT) followed by autologous stem cell transplantation (ASCT) by means of static (whole-body) and dynamic PET/CT (dPET/CT). Thirty-four patients with primary, previously untreated MM scheduled for treatment with HDT followed by ASCT were enrolled in the study. All patients underwent PET/CT scanning with 18 F-FDG and 18 F-NaF before and after therapy. Treatment response by means of PET/CT was assessed according to the European Organization for Research and Treatment of Cancer (EORTC) 1999 criteria. The evaluation of dPET/CT studies was based on qualitative evaluation, semi-quantitative (SUV) calculation, and quantitative analysis based on two-tissue compartment modelling and a non-compartmental approach leading to the extraction of fractal dimension (FD). An analysis was possible in 29 patients: three with clinical complete response (CR) and 26 with non-CR (13 patients near complete response-nCR, four patients very good partial response-VGPR, nine patients partial response-PR). After treatment, 18 F-FDG PET/CT was negative in 14/29 patients and positive in 15/29 patients, showing a sensitivity of 57.5 % and a specificity of 100 %. According to the EORTC 1999 criteria, 18 F-FDG PET/CT-based treatment response revealed CR in 14 patients ( 18 F-FDG PET/CT CR), PR in 11 patients ( 18 F-FDG PET/CT PR) and progressive disease in four patients ( 18 F-FDG PET/CT PD). In terms of 18 F-NaF PET/CT, 4/29 patients (13.8 %) had a negative baseline scan, thus failed to depict MM. Regarding the patients for which a direct lesion-to-lesion comparison was feasible, 18 F-NaF PET/CT depicted 56 of the 129 18 F-FDG positive lesions (43 %). Follow-up 18 F-NaF PET/CT showed persistence of 81.5 % of the baseline 18 F-NaF positive MM lesions after treatment, despite the fact that 64

The simulation of a data acquisition system for a proposed high resolution PET scanner

Energy Technology Data Exchange (ETDEWEB)

Rotolo, C.; Larwill, M.; Chappa, S. [Fermi National Accelerator Lab., Batavia, IL (United States); Ordonez, C. [Chicago Univ., IL (United States)

1993-10-01

The simulation of a specific data acquisition (DAQ) system architecture for a proposed high resolution Positron Emission Tomography (PET) scanner is discussed. Stochastic processes are used extensively to model PET scanner signal timing and probable DAQ circuit limitations. Certain architectural parameters, along with stochastic parameters, are varied to quantatively study the resulting output under various conditions. The inclusion of the DAQ in the model represents a novel method of more complete simulations of tomograph designs, and could prove to be of pivotal importance in the optimization of such designs.

The simulation of a data acquisition system for a proposed high resolution PET scanner

International Nuclear Information System (INIS)

Rotolo, C.; Larwill, M.; Chappa, S.; Ordonez, C.

1993-10-01

The simulation of a specific data acquisition (DAQ) system architecture for a proposed high resolution Positron Emission Tomography (PET) scanner is discussed. Stochastic processes are used extensively to model PET scanner signal timing and probable DAQ circuit limitations. Certain architectural parameters, along with stochastic parameters, are varied to quantatively study the resulting output under various conditions. The inclusion of the DAQ in the model represents a novel method of more complete simulations of tomograph designs, and could prove to be of pivotal importance in the optimization of such designs

Choline-PET/CT for imaging prostate cancer; Cholin-PET/CT zur Bildgebung des Prostatakarzinoms

Energy Technology Data Exchange (ETDEWEB)

Krause, Bernd Joachim [Klinik- und Poliklinik fuer Nuklearmedizin, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany); Treiber, U.; Schwarzenboeck, S.; Souvatzoglou, M. [Klinik fuer Urologie, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany)

2010-09-15

PET and PET/CT using [{sup 11}C]- and [{sup 18}F]-labelled choline derivatives are increasingly being used for imaging of prostate cancer. The value of PET and PET/CT with [{sup 11}C]- and [{sup 18}F]-labelled choline derivates in biochemical recurrence of prostate cancer has been examined in many studies and demonstrates an increasing importance. Primary prostate cancer can be detected with moderate sensitivity using PET and PET/CT using [{sup 11}C]- and [{sup 18}F]-labelled choline derivatives - the differentiation between benign prostatic hyperplasia, prostatitis or high-grade intraepithelial neoplasia (HGPIN) is not always possible. At the present time [{sup 11}C]choline PET/CT is not recommended in the primary setting but may be utilized in clinically suspected prostate cancer with repeatedly negative prostate biopsies, in preparation of a focused re-biopsy. Promising results have been obtained for the use of PET and PET/CT with [{sup 11}C]- and [{sup 18}F]-labelled choline derivates in patients with biochemical recurrence. The detection rate of choline PET and PET/CT for local, regional, and distant recurrence in patients with a biochemical recurrence shows a linear correlation with PSA values at the time of imaging and reaches about 75% in patients with PSA > 3 ng/mL. At PSA values below 1 ng/mL, the recurrence can be diagnosed with choline PET/CT in approximately 1/3 of the patients. PET and PET/CT with [{sup 11}C]- and [{sup 18}F]choline derivates can be helpful for choosing a therapeutic strategy in the sense of an individualized treatment: since an early diagnosis of recurrence is crucial to the choice of optimal treatment. The localization of the site of recurrence - local recurrence, lymph node metastasis or systemic dissemination - has important influence on the therapy regimen. (orig.)

Panel Board From Coconut Fibre And Pet Bottle

Directory of Open Access Journals (Sweden)

Ngadiman Norhayati

2018-01-01

Full Text Available The rate of global deforestation and its impact on the environment has led particle board manufacture to search for alternative feedstock, especially in countries where wood is less available compared to other cellulosic natural product. Based on the properties of coconut fibre and PET bottle, these two materials can be recycle as raw material for manufacture of panel board. As for this study, the coconut fibre were used as the filler and PET bottle as outer lining of the panel board. Two types of coconut fibre were used which are grinding and un-grinding coconut fibre. At first, the coconut fibre are undergoes softening, grinding, drying and sieving process, while PET bottle was cleaning, shredding, sieving before compacted using hydraulic hot press machine. There are four types of testing that been carried out which are swelling, water absorption, Modulus of Elasticity (MOE and Modulus of Rupture (MOR. The result show the conventional board has the highest value for MOE test, so it’s indicate that the conventional board is less strength from the coconut fibre board. As for water absorption test, the average water absorption of coconut fibre based panel board is less than conventional board. Overall, the coconut fibre board is better than conventional panel board because coconut fibre board are less swelling, has low water absorption, high modulus of rupture and low modulus of elasticity. Based on the finding, this coconut fibre panel board has potential as a stronger and long-lasting panel board than the conventional board in the market. Other than that, the panel also have their own aesthetic value since the recycled plastic bottle used as outer lining is colourful and giving aesthetic value.

Initial evaluation of a practical PET respiratory motion correction method in clinical simultaneous PET/MRI

International Nuclear Information System (INIS)

Manber, Richard; Thielemans, Kris; Hutton, Brian; Barnes, Anna; Ourselin, Sebastien; Arridge, Simon; O’Meara, Celia; Atkinson, David

2014-01-01

Respiratory motion during PET acquisitions can cause image artefacts, with sharpness and tracer quantification adversely affected due to count ‘smearing’. Motion correction by registration of PET gates becomes increasingly difficult with shorter scan times and less counts. The advent of simultaneous PET/MRI scanners allows the use of high spatial resolution MRI to capture motion states during respiration [1, 2]. In this work, we use a respiratory signal derived from the PET list-mode data [3, ], with no requirement for an external device or MR sequence modifications.

FDG-PET, PET/CT and conventional nuclear medicine procedures in the evaluation of lung cancer. A systematic review

International Nuclear Information System (INIS)

Hellwig, Dirk; Kirsch, C.M.; Baum, R.P.

2009-01-01

Aim: Currently, the German and Austrian S3 guidelines on the evaluation and treatment of lung cancer are about to be published whereas the American Colleague of Chest Physicians (ACCP) guidelines were already presented in 2007. An important part of the diagnostic workup of lung cancer will be the evaluation of indeterminate lung lesions and the mediastinal and extrathoracic staging using FDG-PET or PET/CT. The results from the literature on FDG-PET and PET/CT as well as on conventional nuclear medicine staging procedures and the clinical implications are presented. Methods: The literature data was amassed in analogy to the metaanalyses drawn for the current ACCP guidelines. In addition, relevant more recent publications were also considered. To answer the important question for the extent of pathological confirmation needed, the residual risk of mediastinal metastases was calculated for certain constellations of FDG-PET and CT findings. Suggested recommendations were characterized with the level of evidence. Results: FDG-PET (PET/CT) allows the differentiation of indeterminate lung lesions with high accuracy. FDG-PET (PET/CT) is the most accurate non-invasive procedure to assess the mediastinal nodal stage, for non-small cell as well as for small cell lung cancer. It is justified to omit invasive evaluation of enlarged but FDG-PET negative lymph nodes under certain circumstances. Unexpected extrathoracic metastases detected by FDG-PET imply important changes in therapeutic management. Conclusion: The upcoming S3 guideline on lung cancer will recommend FDG-PET in several indications due to its clinical efficacy well proven by data from literature (high level of evidence). The selected use of conventional nuclear medicine procedures remains beyond doubt. FDG-PET (PET/CT) belongs to the standard of care in lung cancer

FDG-PET, PET/CT and conventional nuclear medicine procedures in the evaluation of lung cancer. A systematic review

Energy Technology Data Exchange (ETDEWEB)

Hellwig, Dirk; Kirsch, C.M. [Saarland Univ. Medical Center, Homburg (Germany). Dept. of Nuclear Medicine; Baum, R.P. [Zentralklinik Bad Berka (Germany). Dept. of Nuclear Medicine / PET Center

2009-07-01

Aim: Currently, the German and Austrian S3 guidelines on the evaluation and treatment of lung cancer are about to be published whereas the American Colleague of Chest Physicians (ACCP) guidelines were already presented in 2007. An important part of the diagnostic workup of lung cancer will be the evaluation of indeterminate lung lesions and the mediastinal and extrathoracic staging using FDG-PET or PET/CT. The results from the literature on FDG-PET and PET/CT as well as on conventional nuclear medicine staging procedures and the clinical implications are presented. Methods: The literature data was amassed in analogy to the metaanalyses drawn for the current ACCP guidelines. In addition, relevant more recent publications were also considered. To answer the important question for the extent of pathological confirmation needed, the residual risk of mediastinal metastases was calculated for certain constellations of FDG-PET and CT findings. Suggested recommendations were characterized with the level of evidence. Results: FDG-PET (PET/CT) allows the differentiation of indeterminate lung lesions with high accuracy. FDG-PET (PET/CT) is the most accurate non-invasive procedure to assess the mediastinal nodal stage, for non-small cell as well as for small cell lung cancer. It is justified to omit invasive evaluation of enlarged but FDG-PET negative lymph nodes under certain circumstances. Unexpected extrathoracic metastases detected by FDG-PET imply important changes in therapeutic management. Conclusion: The upcoming S3 guideline on lung cancer will recommend FDG-PET in several indications due to its clinical efficacy well proven by data from literature (high level of evidence). The selected use of conventional nuclear medicine procedures remains beyond doubt. FDG-PET (PET/CT) belongs to the standard of care in lung cancer.

The MiniPET: a didactic PET system

International Nuclear Information System (INIS)

Pedro, R; Silva, J; Maio, A; Gurriana, L; Silva, J M; Augusto, J Soares

2013-01-01

The MiniPET project aims to design and build a small PET system. It consists of two 4 × 4 matrices of 16 LYSO scintillator crystals and two PMTs with 16 channels resulting in a low cost system with the essential functionality of a clinical PET instrument. It is designed to illustrate the physics of the PET technique and to provide a didactic platform for the training of students and nuclear imaging professionals as well as for scientific outreach. The PET modules can be configured to test for the coincidence of 511 keV gamma rays. The model has a flexible mechanical setup [1] and can simulate 14 diferent ring geometries, from a configuration with as few as 18 detectors per ring (ring radius φ=51 mm), up to a geometry with 70 detectors per ring (φ=200 mm). A second version of the electronic system [2] allowed measurement and recording of the energy deposited in 4 detector channels by photons from a 137 Cs radioactive source and by photons resulting of the annihilation of positrons from a 22 Na radioactive source. These energy spectra are used for detector performance studies, as well as angular dependency studies. In this paper, the mechanical setup, the front-end high-speed analog electronics, the digital acquisition and control electronics implemented in a FPGA, as well as the data-transfer interface between the FPGA board and a host PC are described. Recent preliminary results obtained with the 4 active channels in the prototype are also presented.

AX-PET: A novel PET concept with G-APD readout

CERN Document Server

Heller, M; Casella, C; Chesi, E; De Leo, R; Dissertori, G; Fanti, V; Gillam, J E; Joram, C; Lustermann, W; Nappi, E; Oliver, J F; Pauss, F; Rafecas, M; Rudge, A; Ruotsalainen, U; Schinzel, D; Schneider, T; Seguinot, J; Solevi, P; Stapnes, S; Tuna, U; Weilhammer, P

2012-01-01

The AX-PET collaboration has developed a novel concept for high resolution PET imaging to overcome some of the performance limitations of classical PET cameras, in particular the compromise between spatial resolution and sensitivity introduced by the parallax error. The detector consists of an arrangement of long LYSO scintillating crystals axially oriented around the field of view together with arrays of wave length shifter strips orthogonal to the crystals. This matrix allows a precise 3D measurement of the photon interaction point. This is valid both for photoelectric absorption at 511 key and for Compton scattering down to deposited energies of about 100 keV. Crystals and WLS strips are individually read out using Geiger-mode Avalanche Photo Diodes (G-APDs). The sensitivity of such a detector can be adjusted by changing the number of layers and the resolution is defined by the crystal and strip dimensions. Two AX-PET modules were built and fully characterized in dedicated test set-ups at CERN, with point-...

Deep-inspiration breath-hold PET/CT versus free breathing PET/CT and respiratory gating PET for reference. Evaluation in 95 patients with lung cancer

International Nuclear Information System (INIS)

Kawano, Tsuyoshi; Ohtake, Eiji; Inoue, Tomio

2011-01-01

The objective of this study was to define the factors that correlate with differences in maximum standardized uptake value (SUV max ) in deep-inspiration breath-hold (DIBH) and free breathing (FB) positron emission tomography (PET)/CT admixed with respiratory gating (RG) PET for reference. Patients (n=95) with pulmonary lesions were evaluated at one facility over 33 months. After undergoing whole-body PET/CT, a RG PET and FB PET/CT scans were obtained, followed by a DIBH PET/CT scan. All scans were recorded using a list-mode dynamic collection method with respiratory gating. The RG PET was reconstructed using phase gating without attenuation correction; the FB PET was reconstructed from the RG PET sinogram datasets with attenuation correction. Respiratory motion distance, breathing cycle speed, and waveform of RG PET were recorded. The SUV max of FB PET/CT and DIBH PET/CT were recorded: the percent difference in SUV max between the FB and DIBH scans was defined as the %BH-index. The %BH-index was significantly higher for lesions in the lower lung area than in the upper lung area. Respiratory motion distance was significantly higher in the lower lung area than in the upper lung area. A significant relationship was observed between the %BH-index and respiratory motion distance. Waveforms without steady end-expiration tended to show a high %BH-index. Significant inverse relationships were observed between %BH-index and cycle speed, and between respiratory motion distance and cycle speed. Decrease in SUV max of FB PET/CT was due to tumor size, distribution of lower lung, long respiratory movement at slow breathing cycle speeds, and respiratory waveforms without steady end-expiration. (author)

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

{sup 18}F-FDG PET/contrast enhanced CT in the standard surveillance of high risk colorectal cancer patients

Energy Technology Data Exchange (ETDEWEB)

Jiménez Londoño, Germán Andrés, E-mail: gjimenez91@yahoo.com [Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); García Vicente, Ana María [Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Sánchez Pérez, Victoria [Department of Oncology, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Jiménez Aragón, Fátima [Department of Radiology, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); León Martin, Alberto [Investigation Unit, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Cano Cano, Juana María [Department of Oncology, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Domínguez Ferreras, Esther [Department of Radiology, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Gómez López, Ober Van [Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Espinosa Arranz, Javier [Department of Oncology, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain); Soriano Castrejón, Ángel María [Department of Nuclear Medicine, Hospital General Universitario de Ciudad Real, Ciudad Real (Spain)

2014-12-15

Highlights: • We assessed the accuracy of FDG-PET/contrast enhanced CT (FDG-PET/ceCT) in the detection of unsuspected recurrence of colorectal cancer. In regard to our knowledge, no previous experience has been reported about the combined acquisition and interpretation of a FDG-PET/ceCT in the surveillance of colorectal cancer. • We designed a prospective study and performed an individual and combined assessment of both techniques (PET and ceCT), in a patient-based analysis and a lesion-based analysis. • The value of PET and ceCT was found to be similar in the detection of unsuspected recurrence of CRC in a patient-based analysis. The most interesting of our result, is that the combined assessment of PET/ceCT improves the accuracy in the lesion-based analysis. - Abstract: Objective: To assess the accuracy of FDG-PET/contrast enhanced CT (FDG-PET/ceCT) in the detection of unsuspected recurrence of colorectal cancer (CRC) in patients with high risk of relapse. Methods: Thirty-three patients (14 females and 19 males, mean age: 62, range: 41–78), with CRC in complete remission, were prospectively included. All patients underwent FDG-PET/ceCT (58 studies). FDG-PET/ceCT was requested in the surveillance setting, and performed following a standardized protocol. A portal venous phase CT scan was performed after the injection of iodinated contrast agent. An individual and combined assessment of both techniques (PET and ceCT) was performed. Concordant and discordant findings of PET, ceCT and FDG-PET/ceCT were compared in a patient-based and a lesion-based analysis. The final diagnosis, recurrence or disease free status (DFS), were established by histopathology or clinical/radiological follow-up of at least 6 months. Results: Seven out of 33 patients had a confirmed recurrence and the rest of patients had a DFS. In a patient-based analysis the sensitivity and specificity of PET, ceCT and PET/ceCT was of 86% and 88%, 86% and 92%, 86% and 85%, respectively. Attending to

Usefulness of low dose oral contrast media in FDG PET/CT

Energy Technology Data Exchange (ETDEWEB)

An, Y. S.; Yun, J. G.; Lee, M. H.; Cho, C. W.; Yun, S. N [Ajou University Medical Center, Suwon (Korea, Republic of)

2004-07-01

Oral contrast media might help in interpreting PET/CT images, allowing better discrimination between physiologic and pathologic abdominal uptake. The aim of this study was to evaluate the usefulness of low dose oral contrast on FDG PET/CT. A total of 435 cancer patients received 200mL of oral Barium with water(200mL) immediately before FDG injection. PET images were reconstructed using attenuation correction and iterative reconstruction. The FDG uptake in gastrointestinal(GI) tract were analyzed by visual and semiquantitative method in transaxial, coronal and sagittal planes. Seventy patients(16%, 113 sites) of 435 images showed high FDG uptake(pSUV>4.0) : 50(74%, 84 sites) with diffuse uptake and 20(26%, 29sites) with focal uptake. The most common distribution site of oral contrast media was small bowel (n=27, 39%) and others were small bowel with transverse colon(n=6, 8%), small bowel with ascending and sigmoid colon(n=6, 8%) and etc. In PET/CT images, FDG uptake coexisted with oral contrast was showed in 26 patients(54%) with diffuse pattern and 9(45%) with focal pattern, and by sites, those were 38(45%) and 9(31%), respectively. In small bowel regions, the most common distribution site, the proportion of coexistence reached as high as 61% (29 in the total 47 sites). Application of low dose contrast agent can be helpful in the evaluation of intestinal uptake in FDG PET/CT image.

Usefulness of low dose oral contrast media in FDG PET/CT

International Nuclear Information System (INIS)

An, Y. S.; Yun, J. G.; Lee, M. H.; Cho, C. W.; Yun, S. N

2004-01-01

Oral contrast media might help in interpreting PET/CT images, allowing better discrimination between physiologic and pathologic abdominal uptake. The aim of this study was to evaluate the usefulness of low dose oral contrast on FDG PET/CT. A total of 435 cancer patients received 200mL of oral Barium with water(200mL) immediately before FDG injection. PET images were reconstructed using attenuation correction and iterative reconstruction. The FDG uptake in gastrointestinal(GI) tract were analyzed by visual and semiquantitative method in transaxial, coronal and sagittal planes. Seventy patients(16%, 113 sites) of 435 images showed high FDG uptake(pSUV>4.0) : 50(74%, 84 sites) with diffuse uptake and 20(26%, 29sites) with focal uptake. The most common distribution site of oral contrast media was small bowel (n=27, 39%) and others were small bowel with transverse colon(n=6, 8%), small bowel with ascending and sigmoid colon(n=6, 8%) and etc. In PET/CT images, FDG uptake coexisted with oral contrast was showed in 26 patients(54%) with diffuse pattern and 9(45%) with focal pattern, and by sites, those were 38(45%) and 9(31%), respectively. In small bowel regions, the most common distribution site, the proportion of coexistence reached as high as 61% (29 in the total 47 sites). Application of low dose contrast agent can be helpful in the evaluation of intestinal uptake in FDG PET/CT image

Click synthesis of PET radiopharmaceuticals

International Nuclear Information System (INIS)

Xu Mei; Kuang Chunxiang

2009-01-01

Increasing attention has been focused on synthesis radiopharmaceuticals for positron emission tomography (PET). The recent years witnessed applications of click chemistry to PET radiopharmaceutical synthesis,because of its distinctive advantages including high speed,yield and stereospecificity under mild conditions. Synthesis of 18 F-labeled and 11 C-labeled radiopharmaceuticals and intermediates via click chemistry are reviewed. The future trend of click chemistry for the synthesis of PET radiopharmaceutical is prospected. (authors)

qPET - a quantitative extension of the Deauville scale to assess response in interim FDG-PET scans in lymphoma

Energy Technology Data Exchange (ETDEWEB)

Hasenclever, Dirk [University of Leipzig, Institute for Medical Informatics, Statistics and Epidemiology (IMISE), Leipzig (Germany); Kurch, Lars; Georgi, Thomas; Sabri, Osama; Kluge, Regine [University Hospital Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Mauz-Koerholz, Christine; Koerholz, Dieter [University Hospital Halle, Department of Pediatrics, Halle (Germany); Elsner, Andreas [Hermes Medical Solutions AB, Stockholm (Sweden); Wallace, Hamish [Royal Hospital for Sick Children, Edinburgh, Scotland (United Kingdom); Landman-Parker, Judith [Hopital d' Enfants Armand Trousseau, Paris (France); Moryl-Bujakowska, Angelina [Jagiellonian University Medical College, Department of Pediatric Oncology and Hematology, Polish-American Institute of Pediatrics, Krakow (Poland); Cepelova, Michaela [Department of Pediatric Hematology and Oncology, Faculty Hospital Motol, Prague (Czech Republic); Karlen, Jonas [Karolinska University Hospital, Pediatric Cancer Unit, Astrid Lindgrens Childrens Hospital, Stockholm (Sweden); Alvarez Fernandez-Teijeiro, Ana [University Hospital Virgen Macarena Avda, Department of Pediatric Oncology and Hematology, Sevilla (Spain); Attarbaschi, Andishe [Medical University of Vienna, Department of Pediatric Hematology and Oncology, St. Anna Children' s Hospital, Vienna (Austria); Fossaa, Alexander [Department of Medical Oncology and Radiotherapy, Rikshospitalet - Radiumhospitalet HF, Oslo (Norway); Pears, Jane [Our Lady' s Children' s Hospital, Crumlin, Dublin (Ireland); Hraskova, Andrea [University Children' s Hospital, Clinic of Pediatric Oncology, Bratislava (Slovakia); Bergstraesser, Eva [University Children' s Hospital, Department Oncology, Zurich (Switzerland); Beishuizen, Auke [MC - Sophia Children' s Hospital, Department of Pediatric Oncology/Hematology, Rotterdam (Netherlands); Uyttebroeck, Anne [University Hospitals of Leuven, Department of Pediatric Hemato-Oncology, Leuven (Belgium); Schomerus, Eckhard [University of Odense (OUH), Department of Pediatric Oncology and Hematology, H. C. Andersen Children' s Hospital, Odense (Denmark)

2014-07-15

Interim FDG-PET is used for treatment tailoring in lymphoma. Deauville response criteria consist of five ordinal categories based on visual comparison of residual tumor uptake to physiological reference uptakes. However, PET-response is a continuum and visual assessments can be distorted by optical illusions. With a novel semi-automatic quantification tool we eliminate optical illusions and extend the Deauville score to a continuous scale. SUV{sub peak} of residual tumors and average uptake of the liver is measured with standardized volumes of interest. The qPET value is the quotient of these measurements. Deauville scores and qPET-values were determined in 898 pediatric Hodgkin's lymphoma patients after two OEPA chemotherapy cycles. Deauville categories translate to thresholds on the qPET scale: Categories 3, 4, 5 correspond to qPET values of 0.95, 1.3 and 2.0, respectively. The distribution of qPET values is unimodal with a peak representing metabolically normal responses and a tail of clearly abnormal outliers. In our patients, the peak is at qPET = 0.95 coinciding with the border between Deauville 2 and 3. qPET cut values of 1.3 or 2 (determined by fitting mixture models) select abnormal metabolic responses with high sensitivity, respectively, specificity. qPET methodology provides semi-automatic quantification for interim FDG-PET response in lymphoma extending ordinal Deauville scoring to a continuous scale. Deauville categories correspond to certain qPET cut values. Thresholds between normal and abnormal response can be derived from the qPET-distribution without need for follow-up data. In our patients, qPET < 1.3 excludes abnormal response with high sensitivity. (orig.)

qPET - a quantitative extension of the Deauville scale to assess response in interim FDG-PET scans in lymphoma

International Nuclear Information System (INIS)

Hasenclever, Dirk; Kurch, Lars; Georgi, Thomas; Sabri, Osama; Kluge, Regine; Mauz-Koerholz, Christine; Koerholz, Dieter; Elsner, Andreas; Wallace, Hamish; Landman-Parker, Judith; Moryl-Bujakowska, Angelina; Cepelova, Michaela; Karlen, Jonas; Alvarez Fernandez-Teijeiro, Ana; Attarbaschi, Andishe; Fossaa, Alexander; Pears, Jane; Hraskova, Andrea; Bergstraesser, Eva; Beishuizen, Auke; Uyttebroeck, Anne; Schomerus, Eckhard

2014-01-01

Interim FDG-PET is used for treatment tailoring in lymphoma. Deauville response criteria consist of five ordinal categories based on visual comparison of residual tumor uptake to physiological reference uptakes. However, PET-response is a continuum and visual assessments can be distorted by optical illusions. With a novel semi-automatic quantification tool we eliminate optical illusions and extend the Deauville score to a continuous scale. SUV peak of residual tumors and average uptake of the liver is measured with standardized volumes of interest. The qPET value is the quotient of these measurements. Deauville scores and qPET-values were determined in 898 pediatric Hodgkin's lymphoma patients after two OEPA chemotherapy cycles. Deauville categories translate to thresholds on the qPET scale: Categories 3, 4, 5 correspond to qPET values of 0.95, 1.3 and 2.0, respectively. The distribution of qPET values is unimodal with a peak representing metabolically normal responses and a tail of clearly abnormal outliers. In our patients, the peak is at qPET = 0.95 coinciding with the border between Deauville 2 and 3. qPET cut values of 1.3 or 2 (determined by fitting mixture models) select abnormal metabolic responses with high sensitivity, respectively, specificity. qPET methodology provides semi-automatic quantification for interim FDG-PET response in lymphoma extending ordinal Deauville scoring to a continuous scale. Deauville categories correspond to certain qPET cut values. Thresholds between normal and abnormal response can be derived from the qPET-distribution without need for follow-up data. In our patients, qPET < 1.3 excludes abnormal response with high sensitivity. (orig.)

Feasibility study of a highly sensitive LaBr{sub 3} PET scanner based on the DOI-dependent extended-energy window

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Eiji [Naitonal Institute of Radiological Sciences, Chiba (Japan)], E-mail: rush@nirs.go.jp; Kitamura, Keishi [Shimadzu Corporation, Kyoto (Japan); Nishikido, Fumihiko; Shibuya, Kengo [Naitonal Institute of Radiological Sciences, Chiba (Japan); Hasegawa, Tomoyuki [Kitasato University, Kanagawa (Japan); Yamaya, Taiga; Inadama, Naoko; Murayama, Hideo [Naitonal Institute of Radiological Sciences, Chiba (Japan)

2009-06-01

Conventionally, positron emission tomograph (PET) scanners use scintillators which have a high effective atomic number. Recently, novel scintillators like LaBr{sub 3} have been developed which have excellent timing and energy resolutions. LaBr{sub 3} has a high performance for PET scanner use, but its effective atomic number is lower than that of lutetium oxyorthosilicate (LSO). As an alternative, we have developed a scatter reduction method using depth-of-interaction (DOI) information and energy information to increase the sensitivity. The sensitivity of the PET scanner with LaBr{sub 3} can be improved using the DOI-dependent extended-energy window (DEEW) method. In this work, our method is applied to the whole-body LSO/LaBr{sub 3} PET scanner using the GATE simulation toolkit. Simulation results show the number of true coincidences can be increased while minimizing the scatter and random coincidences by using the DEEW method. Noise equivalent count rate (NECR) can be improved by 20-70% for the whole-body DOI-PET scanner. Sensitivity of the PET scanner with a scintillator of low-effective atomic number can be improved by the DEEW method.

Prospective evaluation of 18F-FACBC PET/CT and PET/MRI versus multiparametric MRI in intermediate- to high-risk prostate cancer patients (FLUCIPRO trial).

Science.gov (United States)

Jambor, Ivan; Kuisma, Anna; Kähkönen, Esa; Kemppainen, Jukka; Merisaari, Harri; Eskola, Olli; Teuho, Jarmo; Perez, Ileana Montoya; Pesola, Marko; Aronen, Hannu J; Boström, Peter J; Taimen, Pekka; Minn, Heikki

2018-03-01

The purpose of this study was to evaluate 18 F-FACBC PET/CT, PET/MRI, and multiparametric MRI (mpMRI) in detection of primary prostate cancer (PCa). Twenty-six men with histologically confirmed PCa underwent PET/CT immediately after injection of 369 ± 10 MBq 18 F-FACBC (fluciclovine) followed by PET/MRI started 55 ± 7 min from injection. Maximum standardized uptake values (SUV max ) were measured for both hybrid PET acquisitions. A separate mpMRI was acquired within a week of the PET scans. Logan plots were used to calculate volume of distribution (V T ). The presence of PCa was estimated in 12 regions with radical prostatectomy findings as ground truth. For each imaging modality, area under the curve (AUC) for detection of PCa was determined to predict diagnostic performance. The clinical trial registration number is NCT02002455. In the visual analysis, 164/312 (53%) regions contained PCa, and 41 tumor foci were identified. PET/CT demonstrated the highest sensitivity at 87% while its specificity was low at 56%. The AUC of both PET/MRI and mpMRI significantly (p PET/CT while no differences were detected between PET/MRI and mpMRI. SUV max and V T of Gleason score (GS) >3 + 4 tumors were significantly (p PET/CT and PET/MRI demonstrated true-positive findings in only 1/7 patients with metastatic lymph nodes. Quantitative 18 F-FACBC imaging significantly correlated with GS but failed to outperform MRI in lesion detection. 18 F-FACBC may assist in targeted biopsies in the setting of hybrid imaging with MRI.

Impact of temperature and storage time on the migration of antimony from polyethylene terephthalate (PET) containers into bottled water in Qatar.

Science.gov (United States)

Al-Otoum, Fatima; Al-Ghouti, Mohammad A; Costa, Ozeas S; Khraisheh, Majeda

2017-11-12

Prosperity in Qatar and the consequent stresses on water resources resulted in a sustainable increase in the bottled drinking water market. Reports on health concerns and possible migration of chemicals from the plastic material into the water have driven the current investigation. This study aims to address the extent of antimony (Sb) leaching from polyethylene terephthalate (PET) water bottles subject to temperature variations (24-50 °C) due to Qatar's hot climate and improper storage conditions. A representative basket including 66 different imported and locally produced water bottles was considered. The concentrations of Sb in bottled water ranged from 0.168 to 2.263 μg/L at 24 °C and from 0.240 to 6.110 μg/L at 50 °C. Antimony concentrations in PET bottles at 24 °C was significantly lower than those at 50 °C (p = 0.0142), indicating that the temperature was a principal factor affecting the release of Sb from the plastic into the water. Although the detected Sb amounts were below the guidelines endorsed by WHO and Qatar (standard 5 μg/L) at 24 °C, the concentration measured at 50 °C was higher than the recommended WHO values (6.11 μg/L).

Development of compact DOI-measurable PET detectors for simultaneous PET/MR Imaging

Energy Technology Data Exchange (ETDEWEB)

Shao, Yiping; Sun, Xishan [University of Texas MD Anderson Cancer Center (United States); Lou, Kai [Rice University (United States)

2015-05-18

It is critically needed yet challenging to develop compact PET detectors with high sensitivity and uniform, high imaging resolution for improving the performance of simultaneous PET/MR imaging, particularly for an integrated/inserted small-bore system. Using the latest “edge-less” SiPM arrays for DOI measurement using the design of dual-ended-scintillator readout, we developed several compact PET detectors suited for PET/MR imaging. Each detector consists of one LYSO array with each end coupled to a SiPM array. Multiple detectors can be seamlessly tiled together along all sides to form a large detector panel. Detectors with 1.5x1.5 and 2.0x2.0 mm crystals at 20 or 30 mm lengths were studied. Readout of individual SiPM or capacitor-based signal multiplexing was used to transfer 3D interaction position-coded analog signals through flexible-print-circuit cables to dedicated ASIC frontend electronics to output digital timing pulses that encode interaction information. These digital pulses can be transferred to, through standard LVDS cables, and decoded by a FPGA-based data acquisition positioned outside the MRI scanner for coincidence event selection. Initial detector performance measurement shows excellent crystal identification even with 30 mm long crystals, ~18% and 2.8 ns energy and timing resolutions, and around 2-3 mm DOI resolution. A large size detector panel can be scaled up with these modular detectors and different PET systems can be flexibly configured with the scalable readout electronics and data acquisition, providing an important design advantage for different system and application requirements. It is expected that standard shielding of detectors, electronics and signal transfer lines can be applied for simultaneous PET/MR imaging applications, with desired DOI measurement capability to enhance the PET performance and image quality.

Development of compact DOI-measurable PET detectors for simultaneous PET/MR Imaging

International Nuclear Information System (INIS)

Shao, Yiping; Sun, Xishan; Lou, Kai

2015-01-01

It is critically needed yet challenging to develop compact PET detectors with high sensitivity and uniform, high imaging resolution for improving the performance of simultaneous PET/MR imaging, particularly for an integrated/inserted small-bore system. Using the latest “edge-less” SiPM arrays for DOI measurement using the design of dual-ended-scintillator readout, we developed several compact PET detectors suited for PET/MR imaging. Each detector consists of one LYSO array with each end coupled to a SiPM array. Multiple detectors can be seamlessly tiled together along all sides to form a large detector panel. Detectors with 1.5x1.5 and 2.0x2.0 mm crystals at 20 or 30 mm lengths were studied. Readout of individual SiPM or capacitor-based signal multiplexing was used to transfer 3D interaction position-coded analog signals through flexible-print-circuit cables to dedicated ASIC frontend electronics to output digital timing pulses that encode interaction information. These digital pulses can be transferred to, through standard LVDS cables, and decoded by a FPGA-based data acquisition positioned outside the MRI scanner for coincidence event selection. Initial detector performance measurement shows excellent crystal identification even with 30 mm long crystals, ~18% and 2.8 ns energy and timing resolutions, and around 2-3 mm DOI resolution. A large size detector panel can be scaled up with these modular detectors and different PET systems can be flexibly configured with the scalable readout electronics and data acquisition, providing an important design advantage for different system and application requirements. It is expected that standard shielding of detectors, electronics and signal transfer lines can be applied for simultaneous PET/MR imaging applications, with desired DOI measurement capability to enhance the PET performance and image quality.

PET/MRI. Challenges, solutions and perspectives

Energy Technology Data Exchange (ETDEWEB)

Herzog, Hans [Forschungszentrum Juelich (Germany). Inst. of Neuroscience and Medicine - 4

2012-07-01

Already from the start of PET/CT integrating positron emission tomography (PET) and computed tomography (CT) in one instrument, there have been considerations how to combine PET and magnetic resonance imaging (MRI) so that their complementary abilities can be utilized in a single investigation. Since classical PET electronics fail in an even weak magnetic field and PET signal processing might disturb high-frequency signals of MRI, it soon became clear that new solutions had to be found to avoid mutual interferences. During the last fifteen years a number of different approaches towards PET/MRI for small animal imaging have been developed by research groups which together with their specific features are summarized in this review. Recently, PET/MRI for human imaging became available as well - this time by industrial initiatives. First some prototypes of BrainPET/MRI were developed followed by commercial products for simultaneous and non-simultaneous whole-body PET/MRI. Although only PET/MRI integrated in one scanner offers the full diversity of complementary multiparametric imaging, there are also promising applications of non-simultaneous sequential PET/MRI. While describing the present instrumentation for human PET/MRI, this review discusses the challenges and promises related to this new imaging technology. (orig.)

Accuracy of a clinical PET/CT vs. a preclinical μPET system for monitoring treatment effects in tumour xenografts

Energy Technology Data Exchange (ETDEWEB)

Palmowski, Karin [Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen (Germany); Department of Pneumology and Critical Care Medicine, Thoraxklinik Heidelberg, University of Heidelberg, Heidelberg (Germany); Winz, Oliver [Department of Nuclear Medicine, RWTH-Aachen University, Aachen (Germany); Rix, Anne; Bzyl, Jessica [Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen (Germany); Behrendt, Florian F.; Verburg, Frederic A.; Mottaghy, Felix M. [Department of Nuclear Medicine, RWTH-Aachen University, Aachen (Germany); Palmowski, Moritz, E-mail: mpalmowski@ukaachen.de [Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen (Germany); Department of Nuclear Medicine, RWTH-Aachen University, Aachen (Germany); Academic Radiology Baden Baden, Diagnostic and Interventional Radiology, University Medical Center Heidelberg, Heidelberg (Germany)

2013-08-15

Purpose: Small animal imaging is of growing importance for preclinical research and drug development. Tumour xenografts implanted in mice can be visualized with a clinical PET/CT (cPET); however, it is unclear whether early treatment effects can be monitored. Thus, we investigated the accuracy of a cPET versus a preclinical μPET using {sup 18}F-FDG for assessing early treatment effects. Materials and methods: The spatial resolution and the quantitative accuracy of a clinical and preclinical PET were evaluated in phantom experiments. To investigate the sensitivity for assessing treatment response, A431 tumour xenografts were implanted in nude mice. Glucose metabolism was measured in untreated controls and in two therapy groups (either one or four days of antiangiogenic treatment). Data was validated by γ-counting of explanted tissues. Results: In phantom experiments, cPET enabled reliable separation of boreholes ≥ 5 mm whereas μPET visualized boreholes ≥ 2 mm. In animal studies, μPET provided significantly higher tumour-to-muscle ratios for untreated control tumours than cPET (3.41 ± 0.87 vs. 1.60 ± .0.28, respectively; p < 0.01). During treatment, cPET detected significant therapy effects at day 4 (p < 0.05) whereas μPET revealed highly significant therapy effects even at day one (p < 0.01). Correspondingly, γ-counting of explanted tumours indicated significant therapy effects at day one and highly significant treatment response at day 4. Correlation with γ-counting was good for cPET (r = 0.74; p < 0.01) and excellent for μPET (r = 0.85; p < 0.01). Conclusion: Clinical PET is suited to investigate tumour xenografts ≥ 5 mm at an advanced time-point of treatment. For imaging smaller tumours or for the sensitive assessment of very early therapy effects, μPET should be preferred.

WE-G-209-03: PET

Energy Technology Data Exchange (ETDEWEB)

Kemp, B. [Mayo Clinic (United States)

2016-06-15

Digital radiography, CT, PET, and MR are complicated imaging modalities which are composed of many hardware and software components. These components work together in a highly coordinated chain of events with the intent to produce high quality images. Acquisition, processing and reconstruction of data must occur in a precise way for optimum image quality to be achieved. Any error or unexpected event in the entire process can produce unwanted pixel intensities in the final images which may contribute to visible image artifacts. The diagnostic imaging physicist is uniquely qualified to investigate and contribute to resolution of image artifacts. This course will teach the participant to identify common artifacts found clinically in digital radiography, CT, PET, and MR, to determine the causes of artifacts, and to make recommendations for how to resolve artifacts. Learning Objectives: Identify common artifacts found clinically in digital radiography, CT, PET and MR. Determine causes of various clinical artifacts from digital radiography, CT, PET and MR. Describe how to resolve various clinical artifacts from digital radiography, CT, PET and MR.

WE-G-209-03: PET

International Nuclear Information System (INIS)

Kemp, B.

2016-01-01

Digital radiography, CT, PET, and MR are complicated imaging modalities which are composed of many hardware and software components. These components work together in a highly coordinated chain of events with the intent to produce high quality images. Acquisition, processing and reconstruction of data must occur in a precise way for optimum image quality to be achieved. Any error or unexpected event in the entire process can produce unwanted pixel intensities in the final images which may contribute to visible image artifacts. The diagnostic imaging physicist is uniquely qualified to investigate and contribute to resolution of image artifacts. This course will teach the participant to identify common artifacts found clinically in digital radiography, CT, PET, and MR, to determine the causes of artifacts, and to make recommendations for how to resolve artifacts. Learning Objectives: Identify common artifacts found clinically in digital radiography, CT, PET and MR. Determine causes of various clinical artifacts from digital radiography, CT, PET and MR. Describe how to resolve various clinical artifacts from digital radiography, CT, PET and MR.

Qualification test of a MPPC-based PET module for future MRI-PET scanners

Science.gov (United States)

Kurei, Y.; Kataoka, J.; Kato, T.; Fujita, T.; Funamoto, H.; Tsujikawa, T.; Yamamoto, S.

2014-11-01

We have developed a high-resolution, compact Positron Emission Tomography (PET) module for future use in MRI-PET scanners. The module consists of large-area, 4×4 ch MPPC arrays (Hamamatsu S11827-3344MG) optically coupled with Ce:LYSO scintillators fabricated into 12×12 matrices of 1×1 mm2 pixels. At this stage, a pair of module and coincidence circuits was assembled into an experimental prototype gantry arranged in a ring of 90 mm in diameter to form the MPPC-based PET system. The PET detector ring was then positioned around the RF coil of the 4.7 T MRI system. We took an image of a point 22Na source under fast spin echo (FSE) and gradient echo (GE), in order to measure interference between the MPPC-based PET and the MRI. We only found a slight degradation in the spatial resolution of the PET image from 1.63 to 1.70 mm (FWHM; x-direction), or 1.48-1.55 mm (FWHM; y-direction) when operating with the MRI, while the signal-to-noise ratio (SNR) of the MRI image was only degraded by 5%. These results encouraged us to develop a more advanced version of the MRI-PET gantry with eight MPPC-based PET modules, whose detailed design and first qualification test are also presented in this paper.

The value of FDG-PET/CT in assessing single pulmonary nodules in patients at high risk of lung cancer

International Nuclear Information System (INIS)

Kagna, Olga; Solomonov, Anna; Fruchter, Oren; Keidar, Zohar; Bar-Shalom, Rachel; Israel, Ora; Yigla, Mordechai; Guralnik, Luda

2009-01-01

To evaluate whether PET/low-dose CT (ldCT) using 18 F-fluorodeoxyglucose (FDG) improves characterization of indeterminate single pulmonary nodules (SPNs) in patients at high risk of lung cancer. Retrospective analysis of 307 patients who underwent FDG-PET/CT for indeterminate SPNs identified 93 (70 men, age range 46-90 years) at high risk of lung cancer (age >40 years, minimum 10 pack-year smokers). SPNs were evaluated for the presence and intensity of FDG avidity and ldCT patterns. The performance of visual and semiquantitative FDG-PET/ldCT algorithms for characterization of SPNs was compared to that of ldCT. Incongruent FDG-PET and ldCT patterns were analyzed for significance in further patient management. Malignancy was diagnosed in 38% patients. FDG avidity defined 33 SPNs as true-positive (TP) and 2 as false-negative (FN) (malignant), and 41 as true-negative (TN) and 17 as false-positive (FP) (benign). For SUVmax of 2.2 (by ROC analysis) there were 27 TP, 8 FN, 48 TN and 10 FP SPNs. LdCT defined 34 TP, 1 FN, 28 TN and 30 FP lesions. Of the FP lesions on ldCT, 60% were FDG-negative. Visual PET/ldCT analysis had a sensitivity of 94%, a specificity of 70%, an accuracy of 80%, a positive predictive value (PPV) of 66%, and a negative predictive value (NPV) of 95% as compared to 77%, 83%, 81%, 73%, 86% for semiquantitative PET/ldCT and 97%, 48%, 66%, 53%, 96% for ldCT, respectively. Both PET/ldCT algorithms had statistically significantly higher specificity and accuracy than ldCT. Semiquantitative analysis showed significantly higher PPV and lower sensitivity and NPV than found with ldCT. A single screening procedure encompassing FDG-PET and ldCT may improve screening for lung cancer in high-risk patients. The significantly improved specificity may potentially reduce FP ldCT results and further unnecessary invasive procedures. (orig.)

Tiny Turtles Purchased at Pet Stores are a Potential High Risk for Salmonella Human Infection in the Valencian Region, Eastern Spain.

Science.gov (United States)

Marin, Clara; Vega, Santiago; Marco-Jiménez, Francisco

2016-07-01

Turtles may be considered unsafe pets, particularly in households with children. This study aimed to assess Salmonella carriage by turtles in pet stores and in private ownership to inform the public of the potential health risk, enabling informed choices around pet selection. During the period between September and October 2013, 24 pet stores and 96 private owners were sampled in the Valencian Region (Eastern Spain). Salmonella identification procedure was based on ISO 6579: 2002 recommendations (Annex D). Salmonella strains were serotyped in accordance with Kauffman-White-Le-Minor technique. The rate of isolation of Salmonella was very high from pet store samples (75.0% ± 8.8%) and moderate for private owners (29.0% ± 4.6%). Serotyping revealed 18 different serotypes among two Salmonella enterica subspecies: S. enterica subsp. enterica and S. enterica subsp. diarizonae. Most frequently isolated serotypes were Salmonella Typhimurium (39.5%, 17/43) and Salmonella Pomona (9.3%, 4/43). Serotypes identified have previously been reported in turtles, and child Salmonella infections associate with pet turtle exposure. The present study clearly demonstrates that turtles in pet stores, as well as in private owners, could be a direct or indirect source of a high risk of human Salmonella infections. In addition, pet stores should advise their customers of the potential risks associated with reptile ownership.

Arterial spin labeling-based Z-maps have high specificity and positive predictive value for neurodegenerative dementia compared to FDG-PET

Energy Technology Data Exchange (ETDEWEB)

Faellmar, David; Larsson, Elna-Marie [Uppsala University, Department of Surgical Sciences, Radiology, Uppsala (Sweden); Haller, Sven [Uppsala University, Department of Surgical Sciences, Radiology, Uppsala (Sweden); University Medical Center Freiburg, Department of Neuroradiology, Freiburg (Germany); University of Geneva, Faculty of Medicine, Geneva (Switzerland); Affidea CDRC - Centre Diagnostique Radiologique de Carouge, Carouge (Switzerland); Lilja, Johan [Uppsala University, Department of Surgical Sciences, Nuclear Medicine and PET, Uppsala (Sweden); Hermes Medical Solutions, Stockholm (Sweden); Danfors, Torsten [Uppsala University, Department of Surgical Sciences, Nuclear Medicine and PET, Uppsala (Sweden); Kilander, Lena [Uppsala University, Department of Public Health and Caring Sciences, Geriatrics, Uppsala (Sweden); Tolboom, Nelleke; Croon, Philip M.; Berckel, Bart N.M. van [VU University Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Egger, Karl [University Medical Center Freiburg, Department of Neuroradiology, Freiburg (Germany); Kellner, Elias [Medical Center University of Freiburg, Department of Radiology, Medical Physics, Faculty of Medicine, Freiburg (Germany); Verfaillie, Sander C.J.; Ossenkoppele, Rik [VU University Medical Center, Department of Neurology, Alzheimer Center Amsterdam, Amsterdam (Netherlands); Barkhof, Frederik [VU University Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); UCL, Institutes of Neurology and Healthcare Engineering, London (United Kingdom)

2017-10-15

Cerebral perfusion analysis based on arterial spin labeling (ASL) MRI has been proposed as an alternative to FDG-PET in patients with neurodegenerative disease. Z-maps show normal distribution values relating an image to a database of controls. They are routinely used for FDG-PET to demonstrate disease-specific patterns of hypometabolism at the individual level. This study aimed to compare the performance of Z-maps based on ASL to FDG-PET. Data were combined from two separate sites, each cohort consisting of patients with Alzheimer's disease (n = 18 + 7), frontotemporal dementia (n = 12 + 8) and controls (n = 9 + 29). Subjects underwent pseudocontinuous ASL and FDG-PET. Z-maps were created for each subject and modality. Four experienced physicians visually assessed the 166 Z-maps in random order, blinded to modality and diagnosis. Discrimination of patients versus controls using ASL-based Z-maps yielded high specificity (84%) and positive predictive value (80%), but significantly lower sensitivity compared to FDG-PET-based Z-maps (53% vs. 96%, p < 0.001). Among true-positive cases, correct diagnoses were made in 76% (ASL) and 84% (FDG-PET) (p = 0.168). ASL-based Z-maps can be used for visual assessment of neurodegenerative dementia with high specificity and positive predictive value, but with inferior sensitivity compared to FDG-PET. (orig.)

Development of ''Eminence STARGATE'' PET/CT system

International Nuclear Information System (INIS)

Okazaki, Masato; Inoue, Yoshihiro; Amano, Masaharu

2009-01-01

A PET/CT system, the combination of a PET (Positron Emission Tomography) system with an X-ray CT system, has been widely used in recent years. Our newly developed ''Eminence STARGATE'' PET/CT system allows the PET gantry and the X-ray CT gantry to move independently. This advantage provides high flexibility for PET examination and X-ray CT examination and also eases a patient's psychological anxiety about closed spaces. The system has a 16-slice X-ray CT scanner. (author)

An update on the role of PET/CT and PET/MRI in ovarian cancer

International Nuclear Information System (INIS)

Khiewvan, Benjapa; Torigian, Drew A.; Emamzadehfard, Sahra; Paydary, Koosha; Salavati, Ali; Houshmand, Sina; Werner, Thomas J.; Alavi, Abass

2017-01-01

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as 18 F-fluorothymidine (FLT) or 11 C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer. (orig.)

An update on the role of PET/CT and PET/MRI in ovarian cancer

Energy Technology Data Exchange (ETDEWEB)

Khiewvan, Benjapa [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Mahidol University, Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok (Thailand); Torigian, Drew A.; Emamzadehfard, Sahra; Paydary, Koosha; Salavati, Ali; Houshmand, Sina; Werner, Thomas J.; Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States)

2017-06-15

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as {sup 18}F-fluorothymidine (FLT) or {sup 11}C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer. (orig.)

Dynamic 18F-FET PET in newly diagnosed astrocytic low-grade glioma identifies high-risk patients.

Science.gov (United States)

Jansen, Nathalie L; Suchorska, Bogdana; Wenter, Vera; Eigenbrod, Sabina; Schmid-Tannwald, Christine; Zwergal, Andreas; Niyazi, Maximilian; Drexler, Mark; Bartenstein, Peter; Schnell, Oliver; Tonn, Jörg-Christian; Thon, Niklas; Kreth, Friedrich-Wilhelm; la Fougère, Christian

2014-02-01

Because the clinical course of low-grade gliomas in the individual adult patient varies considerably and is unpredictable, we investigated the prognostic value of dynamic (18)F-fluorethyltyrosine ((18)F-FET) PET in the early diagnosis of astrocytic low-grade glioma (World Health Organization grade II). Fifty-nine patients with newly diagnosed low-grade glioma and dynamic (18)F-FET PET before histopathologic assessment were retrospectively investigated. (18)F-FET PET analysis comprised a qualitative visual classification of lesions; assessment of the semiquantitative parameters maximal, mean, and total standardized uptake value as ratio to background and biologic tumor volume; and dynamic analysis of intratumoral (18)F-FET uptake over time (increasing vs. decreasing time-activity curves). The correlation between PET parameters and progression-free survival, overall survival, and time to malignant transformation was investigated. (18)F-FET uptake greater than the background level was found in 34 of 59 tumors. Dynamic (18)F-FET uptake analysis was available for 30 of these 34 patients. Increasing and decreasing time-activity curves were found in 18 and 12 patients, respectively. Neither the qualitative factor presence or absence of (18)F-FET uptake nor any of the semiquantitative uptake parameters significantly influenced clinical outcome. In contrast, decreasing time-activity curves in the kinetic analysis were highly prognostic for shorter progression-free survival and time to malignant transformation (P dynamic (18)F-FET PET constitute an unfavorable prognostic factor in astrocytic low-grade glioma and, by identifying high-risk patients, may ease treatment decisions.

Metallic artifacts caused by dental metal prostheses on PET images. A PET/CT phantom study using different PET/CT scanners

International Nuclear Information System (INIS)

Shimamoto, Hiroaki; Kakimoto, Naoya; Murakami, Shumei; Furukawa, Souhei; Fujino, Kouichi; Hamada, Seiki; Shimosegawa, Eku; Hatazawa, Jun

2009-01-01

The objective of this study was to investigate the effects of computed tomography (CT) artifacts caused by dental metal prostheses on positron emission tomography (PET) images. A dental arch cast was fixed in a cylindrical water-bath phantom. A spherical phantom positioned in the vicinity of the dental arch cast was used to simulate a tumor. To simulate the tumor imaging, the ratio of the 18 F-fluoro-deoxy-glucose radioactivity concentration of the spherical phantom to that of the water-bath phantom was set at 2.5. A dental bridge composed of a gold-silver-palladium alloy on the right mandibular side was prepared. A spherical phantom was set in the white artifact area on the CT images (site A), in a slightly remote area from the white artifact (site B), and in a black artifact area (site C). A PET/CT scan was performed with and without the metal bridge at each simulated tumor site, and the artifactual influence was evaluated on the axial attenuation-corrected (AC) PET images, in which the simulated tumor produced the strongest accumulation. Measurements were performed using three types of PET/CT scanners (scanners 1 and 2 with CT-based attenuation correction, and 3 with Cesium-137 ( 137 Cs)-based attenuation correction). The influence of the metal bridge was evaluated using the change rate of the SUVmean with and without the metal bridge. At site A, an overestimation was shown (scanner 1: +5.0% and scanner 2: +2.5%), while scanner 3 showed an underestimation of -31.8%. At site B, an overestimation was shown (scanner 1: +2.1% and scanner 2: +2.0%), while scanner 3 showed an underestimation of -2.6%. However, at site C, an underestimation was shown (scanner 1: -25.0%, scanner 2: -32.4%, and scanner 3: -8.4%). When CT is used for attenuation correction in patients with dental metal prostheses, an underestimation of radioactivity of accumulated tracer is anticipated in the dark streak artifact area on the CT images. In this study, the dark streak artifacts of the CT

Automatic extraction of forward stroke volume using dynamic PET/CT

DEFF Research Database (Denmark)

Harms, Hans; Tolbod, Lars Poulsen; Hansson, Nils Henrik Stubkjær

2015-01-01

Background The aim of this study was to develop and validate an automated method for extracting forward stroke volume (FSV) using indicator dilution theory directly from dynamic positron emission tomography (PET) studies for two different tracers and scanners. Methods 35 subjects underwent...... a dynamic 11 C-acetate PET scan on a Siemens Biograph TruePoint-64 PET/CT (scanner I). In addition, 10 subjects underwent both dynamic 15 O-water PET and 11 C-acetate PET scans on a GE Discovery-ST PET/CT (scanner II). The left ventricular (LV)-aortic time-activity curve (TAC) was extracted automatically...... from PET data using cluster analysis. The first-pass peak was isolated by automatic extrapolation of the downslope of the TAC. FSV was calculated as the injected dose divided by the product of heart rate and the area under the curve of the first-pass peak. Gold standard FSV was measured using phase...

Prospective evaluation of solitary thyroid nodule on 18F-FDG PET/CT and high-resolution ultrasonography

International Nuclear Information System (INIS)

D'Souza, M.M.; Marwaha, R.K.; Sharma, R.

2010-01-01

The utility of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the assessment of thyroid nodules is unclear as there are several conflicting reports on the usefulness of standardized uptake value (SUV) as an indicator to distinguish benign from malignant thyroid lesions. This study incorporated an additional parameter, namely dual time point imaging, to determine the diagnostic accuracy of PET/CT imaging. The performance of 18F-FDG PET/CT was compared to that of high-resolution ultrasound which is routinely used for the evaluation of thyroid nodules. Two hundred patients with incidentally detected solitary thyroid nodules were included in the study. Each patient underwent ultrasound and PET/CT evaluation within 7 days of each other, reported by an experienced radiologist and nuclear medicine specialist, respectively, in a blinded manner. The PET/CT criteria employed were maximum SUV (SUV max ) at 60 min and change in SUV max at delayed (120 min) imaging. Final diagnosis was based on pathological evaluation and follow-up. Of the 200 patients, 26 had malignant and 174 had benign nodules. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of ultrasound were 80.8, 81.6, 39.6, 96.6 and 81.5%, respectively. Using SUV max at 60 min as the diagnostic criterion, the above indices were 80.8, 84.5, 43.8, 96.7 and 84%, respectively, for PET/CT. The SUV max of malignant thyroid lesions was significantly higher than benign lesions (16.2±10.6 vs. 4.5±3.1, respectively; p=0.0001). Incorporation of percentage change in SUV max at delayed imaging as the diagnostic criterion yielded a slightly improved sensitivity, specificity, PPV, NPV and accuracy of 84.6, 85.6, 46.8, 97.4 and 85.5%, respectively. There was a significant difference in percentage change in SUV max between malignant and benign thyroid lesions (14.9±11.4 vs. -1.6±13.7, respectively; p=0.0001). However, there was no statistically

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

International Nuclear Information System (INIS)

Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

2016-01-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176 Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176 Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

Science.gov (United States)

Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

2016-11-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

Simultaneous PET/MR imaging in a human brain PET/MR system in 50 patients—Current state of image quality

International Nuclear Information System (INIS)

Schwenzer, N.F.; Stegger, L.; Bisdas, S.; Schraml, C.; Kolb, A.; Boss, A.; Müller, M.

2012-01-01

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 [ 18 F]-FDG, [ 11 C]-methionine or [ 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 [ 11 C]-methionine and [ 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 [ 11 C]-methionine; additional lesions were found in 2/8 [ 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 of PET results between PET/MR and PET

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

Brain PET and functional MRI: why simultaneously using hybrid PET/MR systems?

Science.gov (United States)

Cecchin, Diego; Palombit, Alessandro; Castellaro, Marco; Silvestri, Erica; Bui, Franco; Barthel, Henryk; Sabri, Osama; Corbetta, Maurizio; Bertoldo, Alessandra

2017-12-01

In the last 20 years growing attention has been devoted to multimodal imaging. The recent literature is rich of clinical and research studies that have been performed using different imaging modalities on both separate and integrated positron emission tomography (PET) and magnetic resonance (MR) scanners. However, today, hybrid PET/MR systems measure signals related to brain structure, metabolism, neurochemistry, perfusion, and neuronal activity simultaneously, i.e. in the same physiological conditions. A frequently raised question at meeting and symposia is: "Do we really need a hybrid PET/MR system? Are there any advantages over acquiring sequential and separate PET and MR scans?" The present paper is an attempt to answer these questions specifically in relation to PET combined with functional magnetic resonance imaging (fMRI) and arterial spin labeling. We searched (last update: June 2017) the databases PubMed, PMC, Google Scholar and Medline. We also included additional studies if they were cited in the selected articles. No language restriction was applied to the search, but the reviewed articles were all in English. Among all the retrieved articles, we selected only those performed using a hybrid PET/MR system. We found a total of 17 papers that were selected and discussed in three main groups according to the main radiopharmaceutical used: 18F-fluorodeoxyglucose (18F-FDG) (N.=8), 15O-water (15O-H2O) (N.=3) and neuroreceptors (N.=6). Concerning studies using 18F-FDG, simultaneous PET/fMRI revealed that global aspects of functional organization (e.g. graph properties of functional connections) are partially associated with energy consumption. There are remarkable spatial and functional similarities across modalities, but also discrepant findings. More work is needed on this point. There are only a handful of papers comparing blood flow measurements with PET 15O-H2O and MR arterial spin label (ASL) measures, and they show significant regional CBF differences

Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

Energy Technology Data Exchange (ETDEWEB)

Luboldt, Wolfgang [Multiorgan Screening Foundation, Frankfurt (Germany); University Hospital Frankfurt, Department of Radiology, Frankfurt am Main (Germany); University Hospital Dresden, Clinic and Policlinic of Nuclear Medicine, Dresden (Germany); Volker, Teresa; Zoephel, Klaus; Kotzerke, Joerg [University Hospital Dresden, Clinic and Policlinic of Nuclear Medicine, Dresden (Germany); Wiedemann, Baerbel [University Hospital Dresden, Institute of Medical Informatics and Biometrics, Dresden (Germany); Wehrmann, Ursula [University Hospital Dresden, Clinic and Policlinic of Surgery, Dresden (Germany); Koch, Arne; Abolmaali, Nasreddin [University Hospital Dresden, Oncoray, Dresden (Germany); Toussaint, Todd; Luboldt, Hans-Joachim [Multiorgan Screening Foundation, Frankfurt (Germany); Middendorp, Markus; Gruenwald, Frank [University Hospital Frankfurt, Department of Nuclear Medicine, Frankfurt (Germany); Aust, Daniela [University Hospital Dresden, Department of Pathology, Dresden (Germany); Vogl, Thomas J. [University Hospital Frankfurt, Department of Radiology, Frankfurt am Main (Germany)

2010-09-15

To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas {>=}10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off. 84 patients, who underwent PET/CT and colonoscopy (n=79)/sigmoidoscopy (n=5) for (79 x 6+5 x 2)=484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs. Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n=23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n=10) the SUV{sub max} was {>=}5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV{sub max}. FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV{sub max}{>=} 5 improves the accuracy. (orig.)

Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

International Nuclear Information System (INIS)

Luboldt, Wolfgang; Volker, Teresa; Zoephel, Klaus; Kotzerke, Joerg; Wiedemann, Baerbel; Wehrmann, Ursula; Koch, Arne; Abolmaali, Nasreddin; Toussaint, Todd; Luboldt, Hans-Joachim; Middendorp, Markus; Gruenwald, Frank; Aust, Daniela; Vogl, Thomas J.

2010-01-01

To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas ≥10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off. 84 patients, who underwent PET/CT and colonoscopy (n=79)/sigmoidoscopy (n=5) for (79 x 6+5 x 2)=484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs. Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n=23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n=10) the SUV max was ≥5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV max . FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV max ≥ 5 improves the accuracy. (orig.)

FDG PET and PET-CT for the detection of bone metastases in patients with head and neck cancer. A meta-analysis

International Nuclear Information System (INIS)

Yi, Xuelin; Zhang, Hongting; Liu, Shixi; Fan, Min; Liu, Yilin

2013-01-01

We performed a meta-analysis to evaluate 18FDG PET/PET-CT for the detection of bone metastases in patients with head and neck cancer. We calculated sensitivities, specificities, likelihood ratios, and constructed summary receiver operating characteristic curves for PET and PET-CT, respectively. We also compared the performance of PET/PET-CT with that of bone scintigraphy by analysing studies that had also used bone scintigraphy on the same patients. Across 9 PET studies (1621 patients) and 10 PET-CT studies (1291 patients), sensitivity and specificity of PET were 0.81 and 0.99, and of PET-CT were 0.89 and 0.99, respectively. In 5 comparative studies (1184 patients), sensitivity and specificity of PET/PET-CT were 0.85 and 0.98, and of bone scintigraphy were 0.55 and 0.98, respectively. 18FDG PET and PET-CT have high sensitivity and accuracy for the detection of bone metastasis in patients with head and neck cancer.

Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT

International Nuclear Information System (INIS)

Wiesmueller, Marco; Schmidt, Daniela; Beck, Michael; Kuwert, Torsten; Gall, Carl C. von; Quick, Harald H.; Navalpakkam, Bharath; Lell, Michael M.; Uder, Michael; Ritt, Philipp

2013-01-01

PET/MR hybrid scanners have recently been introduced, but not yet validated. The aim of this study was to compare the PET components of a PET/CT hybrid system and of a simultaneous whole-body PET/MR hybrid system with regard to reproducibility of lesion detection and quantitation of tracer uptake. A total of 46 patients underwent a whole-body PET/CT scan 1 h after injection and an average of 88 min later a second scan using a hybrid PET/MR system. The radioactive tracers used were 18 F-deoxyglucose (FDG), 18 F-ethylcholine (FEC) and 68 Ga-DOTATATE (Ga-DOTATATE). The PET images from PET/CT (PET CT ) and from PET/MR (PET MR ) were analysed for tracer-positive lesions. Regional tracer uptake in these foci was quantified using volumes of interest, and maximal and average standardized uptake values (SUV max and SUV avg , respectively) were calculated. Of the 46 patients, 43 were eligible for comparison and statistical analysis. All lesions except one identified by PET CT were identified by PET MR (99.2 %). In 38 patients (88.4 %), the same number of foci were identified by PET CT and by PET MR . In four patients, more lesions were identified by PET MR than by PET CT , in one patient PET CT revealed an additional focus compared to PET MR . The mean SUV max and SUV avg of all lesions determined by PET MR were by 21 % and 11 % lower, respectively, than the values determined by PET CT (p CT and PET MR were minor, but statistically significant. Nevertheless, a more detailed study of the quantitative accuracy of PET MR and the factors governing it is needed to ultimately assess its accuracy in measuring tissue tracer concentrations. (orig.)

Role of hydrogen-bonding and photoinduced electron transfer (PET) on the interaction of resorcinol based acridinedione dyes with Bovine Serum Albumin (BSA) in water

International Nuclear Information System (INIS)

Kumaran, Rajendran; Vanjinathan, Mahalingam; Ramamurthy, Perumal

2015-01-01

Resorcinol based acridinedione (ADDR) dyes are a class of laser dyes and have structural similarity with purine derivatives, nicotinamide adenine dinucleotide (NADH) analogs. These dyes are classified into photoinduced electron transfer (PET) and non-photoinduced electron transfer dyes, and the photophysical properties of family of these dyes exhibiting PET behavior are entirely different from that of non-PET dyes. The PET process in ADDR dyes is governed by the solvent polarity such that an ADDR dye exhibits PET process through space in an aprotic solvent like acetonitrile and does not exhibit the same in protic solvents like water and methanol. A comparison on the fluorescence emission, lifetime and nature of interaction of various ADDR dyes with a large globular protein like Bovine Serum Albumin (BSA) was carried out in aqueous solution. The interaction of PET based ADDR dyes with BSA in water is found to be largely hydrophobic, but hydrogen-bonding interaction of BSA with dye molecule influences the fluorescence emission of the dye and shifts the emission towards red region. Fluorescence spectral studies reveal that the excited state properties of PET based ADDR dyes are largely influenced by the addition of BSA. The microenvironment around the dye results in significant change in the fluorescence lifetime and emission. Fluorescence enhancement with a red shift in the emission results after the addition of BSA to ADDR dyes containing free amino hydrogen in the 10th position of basic acridinedione dye. The amino hydrogen (N–H) in the 10th position of ADDR dye is replaced by methyl group (N–CH 3 ), a significant decrease in the fluorescence intensity with no apparent shift in the emission maximum was observed after the addition of BSA. The nature of interaction between ADDR dyes with BSA is hydrogen-bonding and the dye remains unbound even at the highest concentration of BSA. Circular Dichroism (CD) studies show that the addition of dye to BSA results in a

PET motion correction using PRESTO with ITK motion estimation

Energy Technology Data Exchange (ETDEWEB)

Botelho, Melissa [Institute of Biophysics and Biomedical Engineering, Science Faculty of University of Lisbon (Portugal); Caldeira, Liliana; Scheins, Juergen [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich (Germany); Matela, Nuno [Institute of Biophysics and Biomedical Engineering, Science Faculty of University of Lisbon (Portugal); Kops, Elena Rota; Shah, N Jon [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich (Germany)

2014-07-29

The Siemens BrainPET scanner is a hybrid MRI/PET system. PET images are prone to motion artefacts which degrade the image quality. Therefore, motion correction is essential. The library PRESTO converts motion-corrected LORs into highly accurate generic projection data [1], providing high-resolution PET images. ITK is an open-source software used for registering multidimensional data []. ITK provides motion estimation necessary to PRESTO.

PET motion correction using PRESTO with ITK motion estimation

International Nuclear Information System (INIS)

Botelho, Melissa; Caldeira, Liliana; Scheins, Juergen; Matela, Nuno; Kops, Elena Rota; Shah, N Jon

2014-01-01

The Siemens BrainPET scanner is a hybrid MRI/PET system. PET images are prone to motion artefacts which degrade the image quality. Therefore, motion correction is essential. The library PRESTO converts motion-corrected LORs into highly accurate generic projection data [1], providing high-resolution PET images. ITK is an open-source software used for registering multidimensional data []. ITK provides motion estimation necessary to PRESTO.

PeneloPET, a Monte Carlo PET simulation tool based on PENELOPE: features and validation

Energy Technology Data Exchange (ETDEWEB)

Espana, S; Herraiz, J L; Vicente, E; Udias, J M [Grupo de Fisica Nuclear, Departmento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid (Spain); Vaquero, J J; Desco, M [Unidad de Medicina y CirugIa Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain)], E-mail: jose@nuc2.fis.ucm.es

2009-03-21

Monte Carlo simulations play an important role in positron emission tomography (PET) imaging, as an essential tool for the research and development of new scanners and for advanced image reconstruction. PeneloPET, a PET-dedicated Monte Carlo tool, is presented and validated in this work. PeneloPET is based on PENELOPE, a Monte Carlo code for the simulation of the transport in matter of electrons, positrons and photons, with energies from a few hundred eV to 1 GeV. PENELOPE is robust, fast and very accurate, but it may be unfriendly to people not acquainted with the FORTRAN programming language. PeneloPET is an easy-to-use application which allows comprehensive simulations of PET systems within PENELOPE. Complex and realistic simulations can be set by modifying a few simple input text files. Different levels of output data are available for analysis, from sinogram and lines-of-response (LORs) histogramming to fully detailed list mode. These data can be further exploited with the preferred programming language, including ROOT. PeneloPET simulates PET systems based on crystal array blocks coupled to photodetectors and allows the user to define radioactive sources, detectors, shielding and other parts of the scanner. The acquisition chain is simulated in high level detail; for instance, the electronic processing can include pile-up rejection mechanisms and time stamping of events, if desired. This paper describes PeneloPET and shows the results of extensive validations and comparisons of simulations against real measurements from commercial acquisition systems. PeneloPET is being extensively employed to improve the image quality of commercial PET systems and for the development of new ones.

PeneloPET, a Monte Carlo PET simulation tool based on PENELOPE: features and validation

International Nuclear Information System (INIS)

Espana, S; Herraiz, J L; Vicente, E; Udias, J M; Vaquero, J J; Desco, M

2009-01-01

Monte Carlo simulations play an important role in positron emission tomography (PET) imaging, as an essential tool for the research and development of new scanners and for advanced image reconstruction. PeneloPET, a PET-dedicated Monte Carlo tool, is presented and validated in this work. PeneloPET is based on PENELOPE, a Monte Carlo code for the simulation of the transport in matter of electrons, positrons and photons, with energies from a few hundred eV to 1 GeV. PENELOPE is robust, fast and very accurate, but it may be unfriendly to people not acquainted with the FORTRAN programming language. PeneloPET is an easy-to-use application which allows comprehensive simulations of PET systems within PENELOPE. Complex and realistic simulations can be set by modifying a few simple input text files. Different levels of output data are available for analysis, from sinogram and lines-of-response (LORs) histogramming to fully detailed list mode. These data can be further exploited with the preferred programming language, including ROOT. PeneloPET simulates PET systems based on crystal array blocks coupled to photodetectors and allows the user to define radioactive sources, detectors, shielding and other parts of the scanner. The acquisition chain is simulated in high level detail; for instance, the electronic processing can include pile-up rejection mechanisms and time stamping of events, if desired. This paper describes PeneloPET and shows the results of extensive validations and comparisons of simulations against real measurements from commercial acquisition systems. PeneloPET is being extensively employed to improve the image quality of commercial PET systems and for the development of new ones.

FDG-PET and FDG-PET/CT for therapy monitoring and restaging in malignant lymphoma

International Nuclear Information System (INIS)

Mottaghy, F.M.; Krause, B.J.

2003-01-01

F-18-fluorodeoxyglucose (FDG) PET allows to assess residual masses in patients with malignant lymphoma differentiating vital tumor from scar tissue. This approach is not applicable with conventional imaging methods (CDM) such as CT or MRI. On the other hand circumscribed results often cannot be definitely allocated in PET, therefore the combined morphological-biochemical approach using the now available PET/CT systems promises to be a pathbreaking technical progress. There is no doubt that stand alone PET is superior to CDM differentiating residual scar tissue from vital tumor as has been shown in 15 recently published studies. The median sensitivity for detecting active disease with FDG PET across the studies was 91%; the corresponding specificity was 89%. As a result FDG PET had a high negative predictive value of 94%. In contrast, specificity and positive predictive value (PPV) of CDM in the 9 studies were a direct comparison was available were low (31% and 46%, one study 82%). PET positive residual masses were associated with a progression-free survival of 0 - 55%. Only a few studies have included FDG-PET in therapy response monitoring studies, however also these results are promising. At the moment FDG-PET seems to be the best possibility to characterize and qualitatively visualize vitality of tumor masses and also hold promises for efficient therapy response monitoring in patients with malignant lymphoma. Therefore it should be included in standard diagnostic protocols in lymphoma patients. The combined PET/CT has to be ranked superior to conventional PET studies as in many cases the combined structural and functional imaging brings a clearer diagnostic statement. (orig.) [de

Usefulness of {sup 18}F-FDG PET, combined FDG-PET/CT and EUS in diagnosing primary pancreatic carcinoma: A meta-analysis

Energy Technology Data Exchange (ETDEWEB)

Tang Shuang [Department of Nuclear Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Huang Gang, E-mail: huang2802@163.com [Department of Nuclear Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Liu Jianjun [Department of Nuclear Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Liu Tao [Department of Orthopedics, Soochow University, Suzhou (China); Treven, Lyndal [Faculty of Public Health, University of Sydney, Sydney (Australia); Song Saoli; Zhang Chenpeng; Pan Lingling [Department of Nuclear Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Zhang Ting [Department of Anesthesiology, Renji Hospital, Shanghai (China)

2011-04-15

The aim was to evaluate the diagnostic value of {sup 18}F-fluorodeoxyglucose-positron emission tomography ({sup 18}F-FDG PET), combined {sup 18}F-fluorodeoxyglucose-positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) and endoscopic ultrasonography (EUS) in diagnosing patients with pancreatic carcinoma. MEDLINE, EMBASE, Cochrane library and some other databases, from January 1966 to April 2009, were searched for initial studies. All the studies published in English or Chinese relating to the diagnostic value of {sup 18}F-FDG PET, PET/CT and EUS for patients with pancreatic cancer were collected. Methodological quality was assessed. The statistic software called 'Meta-Disc 1.4' was used for data analysis. Results: 51 studies were included in this meta-analysis. The pooled sensitivity estimate for combined PET/CT (90.1%) was significantly higher than PET (88.4%) and EUS (81.2%). The pooled specificity estimate for EUS (93.2%) was significantly higher than PET (83.1%) and PET/CT (80.1%). The pooled DOR estimate for EUS (49.774) was significantly higher than PET (32.778) and PET/CT (27.105). SROC curves for PET/CT and EUS showed a little better diagnostic accuracy than PET alone. For PET alone, when interpreted the results with knowledge of other imaging tests, its sensitivity (89.4%) and specificity (80.1%) were closer to PET/CT. For EUS, its diagnostic value decreased in differentiating pancreatic cancer for patients with chronic pancreatitis. In conclusion, PET/CT was a high sensitive and EUS was a high specific modality in diagnosing patients with pancreatic cancer. PET/CT and EUS could play different roles during different conditions in diagnosing pancreatic carcinoma.

SmartPET: Applying HPGe and pulse shape analysis to small-animal PET

Energy Technology Data Exchange (ETDEWEB)

Cooper, R.J. [Department of Physics, University of Liverpool (United Kingdom)], E-mail: rjc@ns.ph.liv.ac.uk; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Grint, A.N.; Mather, A.R.; Nolan, P.J.; Scraggs, D.P.; Turk, G. [Department of Physics, University of Liverpool (United Kingdom); Hall, C.J.; Lazarus, I. [CCLRC Daresbury Laboratory, Warrington, Cheshire (United Kingdom); Berry, A.; Beveridge, T.; Gillam, J.; Lewis, R.A. [School of Physics and Materials Engineering, Monash University, Melbourne (Australia)

2007-08-21

The SmartPET project is the development of a prototype small-animal imaging system based on the use of Hyperpure Germanium (HPGe) detectors. The use of digital electronics and application of Pulse Shape Analysis (PSA) techniques provide fine spatial resolution, while the excellent intrinsic energy resolution of HPGe detectors makes the system ideal for multi-nuclide imaging. As a result, the SmartPET system has the potential to function as a dual modality imager, operating as a dual-head Positron Emission Tomography (PET) camera or in a Compton Camera configuration for Single Photon Emission Computed Tomography (SPECT) imaging. In this paper, we discuss how the use of simple PSA techniques greatly improves the position sensitivity of the detector yielding improved spatial resolution in reconstructed images. The PSA methods presented have been validated by comparison to data from high-precision scanning of the detectors. Results from this analysis are presented along with initial images from the SmartPET system, which demonstrates the impact of these techniques on PET images.

Diagnosis and dosimetry in differentiated thyroid carcinoma using 124I PET: comparison of PET/MRI vs PET/CT of the neck

International Nuclear Information System (INIS)

Nagarajah, James; Jentzen, Walter; Hartung, Verena; Rosenbaum-Krumme, Sandra; Bockisch, Andreas; Stahl, Alexander; Mikat, Christian; Heusner, Till Alexander; Antoch, Gerald

2011-01-01

This study compares intrinsically coregistered 124 I positron emission tomography (PET) and CT (PET/CT) and software coregistered 124 I PET and MRI (PET/MRI) images for the diagnosis and dosimetry of thyroid remnant tissues and lymph node metastases in patients with differentiated thyroid carcinoma (DTC). After thyroidectomy, 33 high-risk DTC patients (stage III or higher) received 124 I PET/CT dosimetry prior to radioiodine therapy to estimate the absorbed dose to lesions and subsequently underwent a contrast-enhanced MRI examination of the neck. Images were evaluated by two experienced nuclear medicine physicians and two radiologists to identify the lesions and to categorize their presumable provenience, i.e. thyroid remnant tissue (TT), lymph node metastasis (LN) and inconclusive tissue. The categorization and dosimetry of lesions was initially performed with PET images alone (PET only). Subsequently lesions were reassessed including the CT and MRI data. The analyses were performed on a patient and on a lesion basis. Patient-based analyses showed that 26 of 33 (79%) patients had at least one lesion categorized as TT on PET only. Of these patients, 11 (42%) and 16 (62%) had a morphological correlate on CT and MRI, respectively, in at least one TT PET lesion. Twelve patients (36%) had at least one lesion classified as LN on PET only. Nine (75%) of these patients had a morphological correlate on both CT and MRI in at least one LN PET lesion. Ten patients (30%) showed at least one lesion on PET only classified as inconclusive. The classification was changed to a clear classification in two patients (two LN) by CT and in four (two TT, two LN) patients by MRI. Lesion-based analyses (n = 105 PET positive lesions) resulted in categorization as TT in 61 cases (58%), 16 (26%) of which had a morphological correlate on CT and 33 (54%) on MRI. A total of 29 lesions (27%) were classified as LN on PET, 18 (62%) of which had a morphological correlate on CT and 24 (83%) on MRI

Separation and recycling of cotton from cotton/PET blends by depolymerization of PET catalyzed by bases and ionic liquids

NARCIS (Netherlands)

Bouwhuis, G.H. (Gerrit); Brinks, G.J. (Ger); Groeneveld, R.A.J. (Richard); Oelerich, J. (Jens)

2014-01-01

The recycling of post consumer cotton textile waste is highly requested, due to the high environmental impact of cotton production. Often cotton is mixed in blends with polyethylene terephthalate (PET). For the generation of high value products from recycled cotton, it essential that PET is

Determination of carbonyl compounds (acetaldehyde and formaldehyde in polyethylene terephthalate containers designated for water conservation

Directory of Open Access Journals (Sweden)

Redžepović Azra S.

2012-01-01

Full Text Available Polyethylene terephthalate (PET has in the last several years become the main packaging material for many food products, particularly carbonated beverages and bottled water, as well as for products of chemical industry (packaging of various hygiene maintenance agents, pesticides, solvents, etc.. The strength and permeability properties of PET are very good for packaging of beverages, its resistance to chemicals is high and it has a high degree of transparency. Acetaldehyde and formaldehyde are formed during the thermoforming of PET containers. After cooling, acetaldehyde and formaldehyde remain trapped in the walls of a PET bottle and may migrate into the water after filling and storage. Since there are no migration tests in Serbia prescribed for the determination of acetaldehyde and formaldehyde, the purpose of the paper is to test the quantitative contents of carbonyl compounds (acetaldehyde and formaldehyde in PET containers of different volumes, made by various manufacturers of bottled mineral carbonated and noncarbonated water, and exposed to different temperatures. In this study, the migration of acetaldehyde and formaldehyde from PET bottles into mineral carbonated and noncarbonated water was determined by high performance liquid chromatography. Taking into consideration that formaldehyde and acetaldehyde have no UV active or fluorescent group, the chromatography shall be preceded by derivatization in a closed system (due to a low boiling point of acetaldehyde and formaldehyde, which shall transform carbonyl compounds into UV active compounds.

Effect of Chemical Treatment on Mechanical and Water-Sorption Properties Coconut Fiber-Unsaturated Polyester from Recycled PET

OpenAIRE

Munirah Abdullah, Nurul; Ahmad, Ishak

2012-01-01

Coconut fibers were used as reinforcement for unsaturated polyester resin from recycled PET that has been prepared using glycolysis and polyesterification reaction. Various concentrations of alkali, silane, and silane on alkalized fiber were applied and the optimum concentration of treatments was determined. Morphological and mechanical properties of the composite have also been investigated to study the effect of fiber surface treatment. The influence of water uptake on the sorption characte...

First validation of myocardial flow reserve assessed by dynamic 99mTc-sestamibi CZT-SPECT camera: head to head comparison with 15O-water PET and fractional flow reserve in patients with suspected coronary artery disease. The WATERDAY study.

Science.gov (United States)

Agostini, Denis; Roule, Vincent; Nganoa, Catherine; Roth, Nathaniel; Baavour, Raphael; Parienti, Jean-Jacques; Beygui, Farzin; Manrique, Alain

2018-07-01

We assessed the feasibility of myocardial blood flow (MBF) and flow reserve (MFR) estimation using dynamic SPECT with a novel CZT camera in patients with stable CAD, in comparison with 15 O-water PET and fractional flow reserve (FFR). Thirty patients were prospectively included and underwent FFR measurements in the main coronary arteries (LAD, LCx, RCA). A stenosis ≥50% was considered obstructive and a FFR abnormal if ≤0.8. All patients underwent a dynamic rest/stress 99m Tc-sestamibi CZT-SPECT and 15 O-water PET for MBF and MFR calculation. Net retention kinetic modeling was applied to SPECT data to estimate global uptake values, and MBF was derived using Leppo correction. Ischemia by PET and CZT-SPECT was considered present if MFR was lower than 2 and 2.1, respectively. CZT-SPECT yielded higher stress and rest MBF compared to PET for global and LAD and LCx territories, but not in RCA territory. MFR was similar in global and each vessel territory for both modalities. The sensitivity, specificity, accuracy, positive and negative predictive value of CZT-SPECT were, respectively, 83.3, 95.8, 93.3, 100 and 85.7% for the detection of ischemia and 58.3, 84.6, 81.1, 36.8 and 93% for the detection of hemodynamically significant stenosis (FFR ≤ 0.8). Dynamic 99m Tc-sestamibi CZT-SPECT was technically feasible and provided similar MFR compared to 15 O-water PET and high diagnostic value for detecting impaired MFR and abnormal FFR in patients with stable CAD.

Towards truly integrated hardware fusion with PET/CT

International Nuclear Information System (INIS)

Beyer, T.

2005-01-01

Combined PET/CT imaging is a non-invasive means of acquiring and reviewing both, the anatomy and the molecular pathways of a patient during a quasi-simultaneous examination. Since the introduction of the prototype PET/CT in 1998 this imaging technology has evolved rapidly. State-of-the-art PET/CT tomographs combine the latest technology in spiral, multi-slice CT and PET using novel scintillator materials and image reconstruction techniques. Together with novel patient positioning systems PET/CT tomographs allow to acquire complementary PET and CT data in a single exam with the best intrinsic co-registration. In addition to the hardware integration efforts have been made to integrate the acquisition and viewing software in PET/CT, thus making the diagnostic review and reporting more efficient. Based on the first clinical experiences and the technical evolution of combined imaging technology PET/CT has become a standard in diagnostic oncology. With high-performance imaging technology at hand today, standardized, high-quality PET/CT imaging protocols are needed to provide best oncology patient care. These protocols mandate the joint efforts of a multi-disciplinary team of physicians, physicists and radiochemists. (orig.)

Iodine-124 PET dosimetry in differentiated thyroid cancer: recovery coefficient in 2D and 3D modes for PET(/CT) systems.

Science.gov (United States)

Jentzen, Walter; Weise, Reiner; Kupferschläger, Jürgen; Freudenberg, Lutz; Brandau, Wolfgang; Bares, Ronald; Burchert, Wolfgang; Bockisch, Andreas

2008-03-01

This study evaluated the absolute quantification of iodine-124 ((124)I) activity concentration with respect to the use of this isotope for dosimetry before therapies with (131)I or (131)I-labeled radiotherapeuticals. The recovery coefficients of positron emission tomography(/computed tomography) PET(/CT) systems using (124)I were determined using phantoms and then validated under typical conditions observed in differentiated thyroid cancer (DTC) patients. Transversal spatial resolution and recovery measurements with (124)I and with fluorine-18 ((18)F) as the reference were performed using isotope-containing line sources embedded in water and six isotope-containing spheres 9.7 to 37.0 mm in diameter placed in water-containing body and cylinder phantoms. The cylinder phantom spheres were filled with (18)F only. Measurements in two-dimensional (2D) and three-dimensional (3D) modes were performed using both stand-alone PET (EXACT HR(+)) and combined PET/CT (BIOGRAPH EMOTION DUO) systems. Recovery comparison measurements were additionally performed on a GE ADVANCE PET system using the cylinder phantom. The recovery coefficients were directly determined using the activity concentration of circular regions of interest divided by the prepared activity concentration determined by the dose calibrator. The recovery correction method was validated using three consecutive scans of the body phantom under our (124)I PET(/CT) protocol for DTC patients. Compared with that of (18)F, transversal spatial resolution of (124)I was slightly, but statistically significantly degraded (7.4 mm vs. 8.3 mm, P or =12.6 mm in diameter. Recovery correction is mandatory for (124)I PET quantification, even for large structures. To ensure accurate dosimetry, thorough absolute recovery measurements must be individually established for the particular PET scanner and radionuclide to be used.

Positron Emission Tomography (PET)

International Nuclear Information System (INIS)

Rollo, F.D.; Hines, H.

2001-01-01

ADAC Laboratories has two main imaging strengths: PET and Gamma Cameras. PET's three-dimensional imaging of metabolic function is used in oncology, with emerging opportunties in cardiology, genetic mapping and pharmaceuticals research. In oncology, PET imaging can provide comprehensive and accurate staging information which is not available from CT or MRI. In some cases, this information can lead to modification of treatment, for example from an aggressive approach to one of palliation. The SKYLight is the world's first and only gantry-free camera. It is a dual-detector variable angle camera designed for high throughput, with unsurpassed openness and patient access. (orig.)

Novel geometrical concept of a high-performance brain PET scanner. Principle, design and performance estimates

International Nuclear Information System (INIS)

Seguinot, J.; Braem, A.; Chesi, E.

2006-01-01

We present the principle, a possible implementation and performance estimates of a novel geometrical concept for a high-resolution positron emission tomograph. The concept, which can be for example implemented in a brain PET device, promises to lead to an essentially parallax-free 3D image reconstruction with excellent spatial resolution and contrast, uniform over the complete field of view. The key components are matrices of long axially oriented scintillator crystals which are read out at both extremities by segmented Hybrid Photon Detectors. We discuss the relevant design considerations for a 3D axial PET camera module, motivate parameter and material choices, and estimate its performance in terms of spatial and energy resolution. We support these estimates by Monte Carlo simulations and in some cases by first experimental results. From the performance of a camera module, we extrapolate to the reconstruction resolution of a 3D axial PET scanner in a semi-analytical way and compare it to an existing state-of-the art brain PET device. We finally describe a dedicated data acquisition system, capable to fully exploit the advantages of the proposed concept

Treatment response evaluation with {sup 18}F-FDG PET/CT and {sup 18}F-NaF PET/CT in multiple myeloma patients undergoing high-dose chemotherapy and autologous stem cell transplantation

Energy Technology Data Exchange (ETDEWEB)

Sachpekidis, Christos [German Cancer Research Center (DKFZ), Medical PET Group-Biological Imaging, Clinical Cooperation Unit Nuclear Medicine, Heidelberg (Germany); University of Bern, Department of Nuclear Medicine, Inselspital, Bern University Hospital, Bern (Switzerland); Hillengass, J.; Wagner, B. [University Hospital Heidelberg, Department of Internal Medicine V, Heidelberg (Germany); Goldschmidt, H. [University Hospital Heidelberg, Department of Internal Medicine V, Heidelberg (Germany); National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg (Germany); Haberkorn, U. [German Cancer Research Center (DKFZ), Medical PET Group-Biological Imaging, Clinical Cooperation Unit Nuclear Medicine, Heidelberg (Germany); University of Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); Kopka, K. [German Cancer Research Center (DKFZ), Department of Radiopharmaceutical Chemistry, Heidelberg (Germany); Dimitrakopoulou-Strauss, A. [German Cancer Research Center (DKFZ), Medical PET Group-Biological Imaging, Clinical Cooperation Unit Nuclear Medicine, Heidelberg (Germany)

2017-01-15

The aim of this study was to assess the combined use of the radiotracers {sup 18}F-FDG and {sup 18}F-NaF in treatment response evaluation of a group of multiple myeloma (MM) patients undergoing high-dose chemotherapy (HDT) followed by autologous stem cell transplantation (ASCT) by means of static (whole-body) and dynamic PET/CT (dPET/CT). Thirty-four patients with primary, previously untreated MM scheduled for treatment with HDT followed by ASCT were enrolled in the study. All patients underwent PET/CT scanning with {sup 18}F-FDG and {sup 18}F-NaF before and after therapy. Treatment response by means of PET/CT was assessed according to the European Organization for Research and Treatment of Cancer (EORTC) 1999 criteria. The evaluation of dPET/CT studies was based on qualitative evaluation, semi-quantitative (SUV) calculation, and quantitative analysis based on two-tissue compartment modelling and a non-compartmental approach leading to the extraction of fractal dimension (FD). An analysis was possible in 29 patients: three with clinical complete response (CR) and 26 with non-CR (13 patients near complete response-nCR, four patients very good partial response-VGPR, nine patients partial response-PR). After treatment, {sup 18}F-FDG PET/CT was negative in 14/29 patients and positive in 15/29 patients, showing a sensitivity of 57.5 % and a specificity of 100 %. According to the EORTC 1999 criteria, {sup 18}F-FDG PET/CT-based treatment response revealed CR in 14 patients ({sup 18}F-FDG PET/CT CR), PR in 11 patients ({sup 18}F-FDG PET/CT PR) and progressive disease in four patients ({sup 18}F-FDG PET/CT PD). In terms of {sup 18}F-NaF PET/CT, 4/29 patients (13.8 %) had a negative baseline scan, thus failed to depict MM. Regarding the patients for which a direct lesion-to-lesion comparison was feasible, {sup 18}F-NaF PET/CT depicted 56 of the 129 {sup 18}F-FDG positive lesions (43 %). Follow-up {sup 18}F-NaF PET/CT showed persistence of 81.5 % of the baseline {sup 18}F

Nutritional sustainability of pet foods.

Science.gov (United States)

Swanson, Kelly S; Carter, Rebecca A; Yount, Tracy P; Aretz, Jan; Buff, Preston R

2013-03-01

Sustainable practices meet the needs of the present without compromising the ability of future generations to meet their needs. Applying these concepts to food and feed production, nutritional sustainability is the ability of a food system to provide sufficient energy and essential nutrients required to maintain good health in a population without compromising the ability of future generations to meet their nutritional needs. Ecological, social, and economic aspects must be balanced to support the sustainability of the overall food system. The nutritional sustainability of a food system can be influenced by several factors, including the ingredient selection, nutrient composition, digestibility, and consumption rates of a diet. Carbon and water footprints vary greatly among plant- and animal-based ingredients, production strategy, and geographical location. Because the pet food industry is based largely on by-products and is tightly interlinked with livestock production and the human food system, however, it is quite unique with regard to sustainability. Often based on consumer demand rather than nutritional requirements, many commercial pet foods are formulated to provide nutrients in excess of current minimum recommendations, use ingredients that compete directly with the human food system, or are overconsumed by pets, resulting in food wastage and obesity. Pet food professionals have the opportunity to address these challenges and influence the sustainability of pet ownership through product design, manufacturing processes, public education, and policy change. A coordinated effort across the industry that includes ingredient buyers, formulators, and nutritionists may result in a more sustainable pet food system.

Detection of Cancer with PET and PET/CT in Asymptomatic Volunteers

International Nuclear Information System (INIS)

Chung, Ji In; Choi, Joon Young; Lee, Kyung Han; Kim, Byung Tae; Choi, Yoon Ho; Cho, Han Byoul; Shim, Jae Yong

2009-01-01

We retrospectively investigated the diagnostic performance of 18 F-fluorodeoxyglucose positron emission tomography (PET) and PET/CT for cancer detection in asymptomatic health-check examinees. This study consisted of 5091 PET or PET/CT conducted as part of annual health examination at one hospital from March 1998 to February 2008. To find the incidence of cancers, medical records of the subjects were thoroughly reviewed for a follow-up period of one year. The patterns of formal readings of PET and PET/CT were analyzed to assess the sensitivity and specificity for cancer detection. The histopathology and stage of the cancers were evaluated in relation to the results of PET. Eighty-six cancers (1.7%) were diagnosed within one year after PET or PET/CT. When PET and PET/CT results were combined, the sensitivity was 48.8% and specificity was 81.1% for cancer detection. PET only had a sensitivity of 46.2% and a specificity of 81.4%, and PET/CT only had a sensitivity of 75.0% and a specificity of 78.5% respectively. There were no significant differences in cancer site, stage and histopathology between PET positive and PET negative cancers. In 19.3% of formal readings of PET and PET/CT, further evaluation to exclude malignancy or significant disease was recommended. Head and neck area and upper gastrointestinal tract were commonly recommended sites for further evaluation. PET and PET/CT showed moderate performance for detecting cancers in asymptomatic adults in this study. More experience and further investigation are needed to overcome limitations of PET and PET/CT for cancer screening

Comparison of 18F-FET PET and perfusion-weighted MRI for glioma grading. A hybrid PET/MR study

International Nuclear Information System (INIS)

Verger, Antoine; Filss, Christian P.; Lohmann, Philipp; Stoffels, Gabriele; Rota Kops, Elena; Sabel, Michael; Wittsack, Hans J.; Galldiks, Norbert; Fink, Gereon R.; Shah, Nadim J.; Langen, Karl-Josef

2017-01-01

Both perfusion-weighted MR imaging (PWI) and O-(2- 18 F-fluoroethyl)-L-tyrosine PET ( 18 F-FET) provide grading information in cerebral gliomas. The aim of this study was to compare the diagnostic value of 18 F-FET PET and PWI for tumor grading in a series of patients with newly diagnosed, untreated gliomas using an integrated PET/MR scanner. Seventy-two patients with untreated gliomas [22 low-grade gliomas (LGG), and 50 high-grade gliomas (HGG)] were investigated with 18 F-FET PET and PWI using a hybrid PET/MR scanner. After visual inspection of PET and PWI maps (rCBV, rCBF, MTT), volumes of interest (VOIs) with a diameter of 16 mm were centered upon the maximum of abnormality in the tumor area in each modality and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios (TBR mean , TBR max ) were calculated. In addition, Time-to-Peak (TTP) and slopes of time-activity curves were calculated for 18 F-FET PET. Diagnostic accuracies of 18 F-FET PET and PWI for differentiating low-grade glioma (LGG) from high-grade glioma (HGG) were evaluated by receiver operating characteristic analyses (area under the curve; AUC). The diagnostic accuracy of 18 F-FET PET and PWI to discriminate LGG from HGG was similar with highest AUC values for TBR mean and TBR max of 18 F-FET PET uptake (0.80, 0.83) and for TBR mean and TBR max of rCBV (0.80, 0.81). In case of increased signal in the tumor area with both methods (n = 32), local hot-spots were incongruent in 25 patients (78%) with a mean distance of 10.6 ± 9.5 mm. Dynamic FET PET and combination of different parameters did not further improve diagnostic accuracy. Both 18 F-FET PET and PWI discriminate LGG from HGG with similar diagnostic performance. Regional abnormalities in the tumor area are usually not congruent indicating that tumor grading by 18 F-FET PET and PWI is based on different pathophysiological phenomena. (orig.)

Gamma-camera 18F-FDG PET in diagnosis and staging of patients presenting with suspected lung cancer and comparison with dedicated PET

DEFF Research Database (Denmark)

Oturai, Peter S; Mortensen, Jann; Enevoldsen, Henriette

2004-01-01

It is not clear whether high-quality coincidence gamma-PET (gPET) cameras can provide clinical data comparable with data obtained with dedicated PET (dPET) cameras in the primary diagnostic work-up of patients with suspected lung cancer. This study focuses on 2 main issues: direct comparison...

Prospective evaluation of {sup 18}F-FACBC PET/CT and PET/MRI versus multiparametric MRI in intermediate- to high-risk prostate cancer patients (FLUCIPRO trial)

Energy Technology Data Exchange (ETDEWEB)

Jambor, Ivan [University of Turku, Department of Diagnostic Radiology, Turku (Finland); University of Massachusetts Medical School - Baystate, Department of Radiology, Springfield, MA (United States); Turku PET Centre, Turku (Finland); Kuisma, Anna [Turku University Hospital, Department of Oncology and Radiotherapy, Turku (Finland); Kaehkoenen, Esa; Bostroem, Peter J. [Turku University Hospital, Department of Urology, Turku (Finland); Kemppainen, Jukka [Turku PET Centre, Turku (Finland); Turku University Hospital, Department of Clinical Physiology and Nuclear Medicine, Turku (Finland); Merisaari, Harri [University of Turku, Department of Diagnostic Radiology, Turku (Finland); Turku PET Centre, Turku (Finland); University of Turku, Department of Information Technology, Turku (Finland); Eskola, Olli; Teuho, Jarmo [Turku PET Centre, Turku (Finland); Montoya Perez, Ileana [University of Turku, Department of Diagnostic Radiology, Turku (Finland); University of Turku, Department of Information Technology, Turku (Finland); Turku University Hospital, Medical Imaging Centre of Southwest Finland, Turku (Finland); Pesola, Marko [University of Turku, Department of Diagnostic Radiology, Turku (Finland); Aronen, Hannu J. [University of Turku, Department of Diagnostic Radiology, Turku (Finland); Turku University Hospital, Medical Imaging Centre of Southwest Finland, Turku (Finland); Taimen, Pekka [University of Turku and Turku University Hospital, Department of Pathology, Turku (Finland); Minn, Heikki [Turku PET Centre, Turku (Finland); Turku University Hospital, Department of Oncology and Radiotherapy, Turku (Finland)

2018-03-15

The purpose of this study was to evaluate {sup 18}F-FACBC PET/CT, PET/MRI, and multiparametric MRI (mpMRI) in detection of primary prostate cancer (PCa). Twenty-six men with histologically confirmed PCa underwent PET/CT immediately after injection of 369 ± 10 MBq {sup 18}F-FACBC (fluciclovine) followed by PET/MRI started 55 ± 7 min from injection. Maximum standardized uptake values (SUV{sub max}) were measured for both hybrid PET acquisitions. A separate mpMRI was acquired within a week of the PET scans. Logan plots were used to calculate volume of distribution (V{sub T}). The presence of PCa was estimated in 12 regions with radical prostatectomy findings as ground truth. For each imaging modality, area under the curve (AUC) for detection of PCa was determined to predict diagnostic performance. The clinical trial registration number is NCT02002455. In the visual analysis, 164/312 (53%) regions contained PCa, and 41 tumor foci were identified. PET/CT demonstrated the highest sensitivity at 87% while its specificity was low at 56%. The AUC of both PET/MRI and mpMRI significantly (p < 0.01) outperformed that of PET/CT while no differences were detected between PET/MRI and mpMRI. SUV{sub max} and V{sub T} of Gleason score (GS) >3 + 4 tumors were significantly (p < 0.05) higher than those for GS 3 + 3 and benign hyperplasia. A total of 442 lymph nodes were evaluable for staging, and PET/CT and PET/MRI demonstrated true-positive findings in only 1/7 patients with metastatic lymph nodes. Quantitative {sup 18}F-FACBC imaging significantly correlated with GS but failed to outperform MRI in lesion detection. {sup 18}F-FACBC may assist in targeted biopsies in the setting of hybrid imaging with MRI. (orig.)

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic {sup 176}Lu radiation of PET detector

Energy Technology Data Exchange (ETDEWEB)

Wei, Qingyang [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Ma, Tianyu; Wang, Shi; Liu, Yaqiang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Gu, Yu, E-mail: guyu@ustb.edu.cn [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Dai, Tiantian, E-mail: maxinedtt@163.com [Department of Radiation Oncology, China-Japan Friendship Hospital, Beijing 100029 (China)

2016-11-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic {sup 176}Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic {sup 176}Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

Temporal and spatial variability of global water balance

Science.gov (United States)

McCabe, Gregory J.; Wolock, David M.

2013-01-01

An analysis of simulated global water-balance components (precipitation [P], actual evapotranspiration [AET], runoff [R], and potential evapotranspiration [PET]) for the past century indicates that P has been the primary driver of variability in R. Additionally, since about 2000, there have been increases in P, AET, R, and PET for most of the globe. The increases in R during 2000 through 2009 have occurred despite unprecedented increases in PET. The increases in R are the result of substantial increases in P during the cool Northern Hemisphere months (i.e. October through March) when PET increases were relatively small; the largest PET increases occurred during the warm Northern Hemisphere months (April through September). Additionally, for the 2000 through 2009 period, the latitudinal distribution of P departures appears to co-vary with the mean P departures from 16 climate model projections of the latitudinal response of P to warming, except in the high latitudes. Finally, changes in water-balance variables appear large from the perspective of departures from the long-term means. However, when put into the context of the magnitudes of the raw water balance variable values, there appears to have been little change in any of the water-balance variables over the past century on a global or hemispheric scale.

PET

DEFF Research Database (Denmark)

Mariager, Rasmus Mølgaard; Schmidt, Regin; Heiberg, Morten Rievers

PET handler om den hemmelige tjenestes arbejde under den kolde krig 1945-1989. Her fortæller Regin Schmidt, Rasmus Mariager og Morten Heiberg om de mest dramatiske og interessante sager fra PET's arkiv. PET er på flere måder en udemokratisk institution, der er sat til at vogte over demokratiet....... Dens virksomhed er skjult for offentligheden, den overvåger borgernes aktiviteter, og den registrerer følsomme personoplysninger. Historien om PET rejser spørgsmålet om, hvad man skal gøre, når befolkningen i et demokrati er kritisk indstillet over for overvågningen af lovlige politiske aktiviteter......, mens myndighederne mener, at det er nødvendigt for at beskytte demokratiet. PET er på en gang en fortælling om konkrete aktioner og begivenheder i PET's arbejde og et stykke Danmarkshistorie. Det handler om overvågning, spioner, politisk ekstremisme og international terrorisme.  ...

Evaluation of the ECAT EXACT HR+ 3D PET scanner in 15O-water brain activation studies

International Nuclear Information System (INIS)

Moreno-Cantu, J.J.; Thompson, C.J.; Zatorre, R.J.

1996-01-01

We evaluated the performance of the ECAT EXACT HR + 3D whole body PET scanner when employed to measure brain function using 15 O-water-bolus activation protocols in single data acquisition sessions. Using vibrotactile and auditory stimuli as independent activation tasks, we studied the scanner's performance under different imaging conditions in four healthy volunteers. Cerebral blood flow images were acquired from each volunteer using 15 O-water-bolus injections of activity varying from 5 to 20mCi. Performance characteristics. The scanner's dead time grew linearly with injected dose from 10% to 25%. Random events varied from 30% to 50% of the detected events. Scattered events were efficiently corrected at all doses. Noise-effective-count curves plateau at about 15mCi. One-session 12-injection bolus PET activation protocol. Using an acquisition protocol that accounts for the scanner's performance and the practical aspects of imaging volunteers and patients in one session, we assessed the correlation between the statistical significance of activation foci and the dose per injection used The one-session protocol employs 12 bolus injections per subject. We present evidence suggesting that 15-20mCi is the optimal dose per injection to be used routinely in one-time scanning sessions

Development of scintillation materials for PET scanners

CERN Document Server

Korzhik, Mikhail; Annenkov, Alexander N; Borissevitch, Andrei; Dossovitski, Alexei; Missevitch, Oleg; Lecoq, Paul

2007-01-01

The growing demand on PET methodology for a variety of applications ranging from clinical use to fundamental studies triggers research and development of PET scanners providing better spatial resolution and sensitivity. These efforts are primarily focused on the development of advanced PET detector solutions and on the developments of new scintillation materials as well. However Lu containing scintillation materials introduced in the last century such as LSO, LYSO, LuAP, LuYAP crystals still remain the best PET species in spite of the recent developments of bright, fast but relatively low density lanthanum bromide scintillators. At the same time Lu based materials have several drawbacks which are high temperature of crystallization and relatively high cost compared to alkali-halide scintillation materials. Here we describe recent results in the development of new scintillation materials for PET application.

PET in cerebrovascular disease; PET bei zerebrovaskulaeren Erkrankungen

Energy Technology Data Exchange (ETDEWEB)

Herholz, K. [Neurologische Universitaetsklinik der Univ. Koeln (Germany)]|[Max-Planck-Institut fuer Neurologische Forschung, Koeln (Germany)

1997-03-01

Tissue viability is of particular interest in acute cerebral ischemia because it may be preserved if reperfusion can be achieved rapidly, e.g. by acute thrombolysis. Measurements of regional cerebral blood flow (CBF) and oxygen consumption by PET can assess tissue viability, and they have substantially increased our knowledge of th pathophysiology of ischemic stroke and the associated penumbra. Widerspread clinical application in acute stroke, however, is unlikely because of the large logistic and personnel resources required. In chronic cerebrovascular disease, measurement of regional CBF and glucose metabolism, which is usually coupled, provide detailed insights in disturbance of cortical function, e.g. due to deafferentiation, and contribute to differentiation of dementia types. Chronic misery perfusion, i.e. reduced perfusion that does not match the metabolic demand of the tissue, can be demonstrated by PET. It may be found in some patients with high-grade arterial stenoses. Less severe impairment of brain perfusion can be demonstrated by measurement of the cerebrovascular reserve capacity. The most frequent clinical situations can be assessed by less demanding procedures, e.g. by SPECT. In conclusion, PET has its role in cerebrovascular disease primarily within scientific studies, where high resolution and absolute quantitation of physiological variables are essential. (orig.). 65 refs. [Deutsch] Beim akuten ischaemischen Insult ist die Vitalitaet des Gewebes von besonderem Interesse, da sie durch rasche Reperfusion, z.B. durch Thrombolyse, erhalten bleiben kann. Messungen der zerebralen Durchblutung und des Sauerstoffumsatzes mittels PET geben darueber wesentliche Aufschluesse, und sie sind wichtig fuer das Verstaendnis der Pathophysiologie ischaemischer Infarkte und der Penumbra mit kritischer Perfusion beim Menschen. Ihre breitere Anwendung in der klinischen Patientenversorgung kommt allerdings wegen des hohen Aufwandes derzeit kaum in Betracht. Bei

High performance ZnO:Al films deposited on PET substrates using facing target sputtering

Science.gov (United States)

Guo, Tingting; Dong, Guobo; Gao, Fangyuan; Xiao, Yu; Chen, Qiang; Diao, Xungang

2013-10-01

ZnO:Al (ZAO) thin films have been deposited on flexible PET substrates using a plasma damage-free facing target sputtering system at room temperature. The structure, surface morphology, electrical and optical properties were investigated as a function of working power. All the samples have a highly preferred orientation of the c-axis perpendicular to the PET substrate and have a high quality surface. With increased working power, the carrier concentration changes slightly, the mobility increases at the beginning and decreases after it reaches a maximum value, in line with electrical conductivity. The figure of merit has been significantly improved with increasing of the working power. Under the optimized condition, the lowest resistivity of 1.3 × 10-3 Ω cm with a sheet resistance of 29 Ω/□ and the relative visible transmittance above 93% in the visible region were obtained.

High performance ZnO:Al films deposited on PET substrates using facing target sputtering

International Nuclear Information System (INIS)

Guo, Tingting; Dong, Guobo; Gao, Fangyuan; Xiao, Yu; Chen, Qiang; Diao, Xungang

2013-01-01

ZnO:Al (ZAO) thin films have been deposited on flexible PET substrates using a plasma damage-free facing target sputtering system at room temperature. The structure, surface morphology, electrical and optical properties were investigated as a function of working power. All the samples have a highly preferred orientation of the c-axis perpendicular to the PET substrate and have a high quality surface. With increased working power, the carrier concentration changes slightly, the mobility increases at the beginning and decreases after it reaches a maximum value, in line with electrical conductivity. The figure of merit has been significantly improved with increasing of the working power. Under the optimized condition, the lowest resistivity of 1.3 × 10 −3 Ω cm with a sheet resistance of 29 Ω/□ and the relative visible transmittance above 93% in the visible region were obtained.

Clinical usefulness of PET in the management of oral cancer. Comparison between FDG-PET and MET-PET

International Nuclear Information System (INIS)

Kitagawa, Yoshimasa; Saitoh, Masaaki; Nakamura, Mikiko

2007-01-01

Inductive chemoradiotherapy has played an important role in preserving organs and functions in patients with oral squamous cell carcinoma (SCC). To determine whether a reduced form of surgery should be performed after chemoradiotherapy, accurate evaluation of residual tumor cells is essential. We investigated the clinical value of positron emission tomography with 18 F labeled fluorodeoxyglucose (FDG-PET) in the management of oral SCCs. Forty-five patients underwent two FDG-PET studies, one prior to and one at 6 weeks after the chemoradiotherapy. Pretreatment FDG-PET was useful in predicting the response to treatment. Posttreatment FDG-PET could evaluate residual viable cells and prognosis. Organ preservation may be feasible based on PET evaluation. Hence FDG-PET is a valuable tool in the treatment of oral cancer. 11 C-Methionine (MET) is another promising tracer for PET that can be used to assess metabolic demand for amino acids in cancer cells. A MET-PET and FDG-PET study was performed during the same period to investigate diagnostic accuracy in 40 oral malignancies. Sensitivity and positive predictive value of MET-PET were 95% and 100%, respectively, and were comparable with those of FDG-PET. Further study is required to determine the diagnostic significance of MET-PET in evaluating response to chemoradiotherapy. (author)

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

International Nuclear Information System (INIS)

Jung, Jin Ho; Choi, Yong; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

2015-01-01

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

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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 70x60x1 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

Evaluation of attenuation correction in cardiac PET using PET/MR.

Science.gov (United States)

Lau, Jeffrey M C; Laforest, R; Sotoudeh, H; Nie, X; Sharma, S; McConathy, J; Novak, E; Priatna, A; Gropler, R J; Woodard, P K

2017-06-01

Simultaneous acquisition Positron emission tomography/magnetic resonance (PET/MR) is a new technology that has potential as a tool both in research and clinical diagnosis. However, cardiac PET acquisition has not yet been validated using MR imaging for attenuation correction (AC). The goal of this study is to evaluate the feasibility of PET imaging using a standard 2-point Dixon volume interpolated breathhold examination (VIBE) MR sequence for AC. Evaluation was performed in both phantom and patient data. A chest phantom containing heart, lungs, and a lesion insert was scanned by both PET/MR and PET/CT. In addition, 30 patients underwent whole-body 18 F-fluorodeoxyglucose PET/CT followed by simultaneous cardiac PET/MR. Phantom study showed 3% reduction of activity values in the myocardium due to the non-inclusion of the phased array coil in the AC. In patient scans, average standardized uptake values (SUVs) obtained by PET/CT and PET/MR showed no significant difference (n = 30, 4.6 ± 3.5 vs 4.7 ± 2.8, P = 0.47). There was excellent per patient correlation between the values acquired by PET/CT and PET/MR (R 2  = 0.97). Myocardial SUVs PET imaging using MR for AC shows excellent correlation with myocardial SUVs obtained by standard PET/CT imaging. The 2-point Dixon VIBE MR technique can be used for AC in simultaneous PET/MR data acquisition.

Automatic extraction of forward stroke volume using dynamic PET/CT: a dual-tracer and dual-scanner validation in patients with heart valve disease.

Science.gov (United States)

Harms, Hendrik Johannes; Tolbod, Lars Poulsen; Hansson, Nils Henrik Stubkjær; Kero, Tanja; Orndahl, Lovisa Holm; Kim, Won Yong; Bjerner, Tomas; Bouchelouche, Kirsten; Wiggers, Henrik; Frøkiær, Jørgen; Sörensen, Jens

2015-12-01

The aim of this study was to develop and validate an automated method for extracting forward stroke volume (FSV) using indicator dilution theory directly from dynamic positron emission tomography (PET) studies for two different tracers and scanners. 35 subjects underwent a dynamic (11)C-acetate PET scan on a Siemens Biograph TruePoint-64 PET/CT (scanner I). In addition, 10 subjects underwent both dynamic (15)O-water PET and (11)C-acetate PET scans on a GE Discovery-ST PET/CT (scanner II). The left ventricular (LV)-aortic time-activity curve (TAC) was extracted automatically from PET data using cluster analysis. The first-pass peak was isolated by automatic extrapolation of the downslope of the TAC. FSV was calculated as the injected dose divided by the product of heart rate and the area under the curve of the first-pass peak. Gold standard FSV was measured using phase-contrast cardiovascular magnetic resonance (CMR). FSVPET correlated highly with FSVCMR (r = 0.87, slope = 0.90 for scanner I, r = 0.87, slope = 1.65, and r = 0.85, slope = 1.69 for scanner II for (15)O-water and (11)C-acetate, respectively) although a systematic bias was observed for both scanners (p dynamic PET/CT and cluster analysis. Results are almost identical for (11)C-acetate and (15)O-water. A scanner-dependent bias was observed, and a scanner calibration factor is required for multi-scanner studies. Generalization of the method to other tracers and scanners requires further validation.

PET-CT and PET-MRI of the prostate. From {sup 18}F-FDG to {sup 68}Ga-PSMA; PET-CT/-MRT der Prostata. Von {sup 18}F-FDG zu {sup 68}Ga-PSMA

Energy Technology Data Exchange (ETDEWEB)

Knorr, K.; Eiber, M.; Scheidhauer, K. [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Muenchen (Germany); Maurer, T. [Technische Universitaet Muenchen, Urologische Klinik und Poliklinik, Klinikum rechts der Isar, Muenchen (Germany); Wester, H.J. [Technische Universitaet Muenchen, Pharmazeutische Radiochemie, Garching (Germany)

2017-08-15

In the last few years nuclear medical diagnostics have experienced a unprecedented renaissance in the diagnostics of prostate cancer, due to the availability of hybrid imaging with positron emission tomography computed tomography (PET/CT), PET magnetic resonance imaging (PET/MRI) and single photon emission computed tomography (SPECT) CT as well as the development of prostate-specific radiopharmaceuticals. The use of fluorodeoxyglucose (FDG), which has been successfully implemented for many years in PET diagnostics, is only helpful in dedifferentiated tumors due to the biological characteristics of prostate cancer. New specific radiopharmaceuticals, such as choline-derivatives, which are incorporated into the prostate cancer cell and built into the cell membrane as well as the recently developed highly specific ligands for prostate-specific membrane antigen (PSMA) are revolutionizing prostate cancer imaging and (re-) staging. The {sup 68} Ga-labeled PSMA ligands for PET-CT and PET-MRI are highly specific tracers for primary diagnostics and detection of metastases of prostate carcinoma. In risk patients, which includes patients with intermediate and high-risk tumors, they have largely replaced choline-based PET-CT, especially in the case of very low PSA values <0.5 ng/ml in the diagnostics of recurrence. The use in the primary diagnostics as PET-MRI, also in combination with multiparametric MRI (mpMRI), is promising with respect to early diagnostics and image fusion-assisted biopsy as well as surgery and irradiation planning. (orig.) [German] Die nuklearmedizinische Diagnostik hat in den letzten Jahren bei der Bildgebung des Prostatakarzinoms eine rasante Entwicklung erlebt, sowohl aufgrund der verfuegbaren Hybridbildgebung mit der Positronenemissionstomographie(PET)-CT, PET-MRT sowie der Single-photon-emission-computed-tomography(SPECT)-CT als auch durch die Entwicklung prostataspezifischer Radiopharmaka. Die in der PET-Diagnostik seit Jahren erfolgreich eingesetzte

High-resolution dynamic imaging and quantitative analysis of lung cancer xenografts in nude mice using clinical PET/CT.

Science.gov (United States)

Wang, Ying Yi; Wang, Kai; Xu, Zuo Yu; Song, Yan; Wang, Chu Nan; Zhang, Chong Qing; Sun, Xi Lin; Shen, Bao Zhong

2017-08-08

Considering the general application of dedicated small-animal positron emission tomography/computed tomography is limited, an acceptable alternative in many situations might be clinical PET/CT. To estimate the feasibility of using clinical PET/CT with [F-18]-fluoro-2-deoxy-D-glucose for high-resolution dynamic imaging and quantitative analysis of cancer xenografts in nude mice. Dynamic clinical PET/CT scans were performed on xenografts for 60 min after injection with [F-18]-fluoro-2-deoxy-D-glucose. Scans were reconstructed with or without SharpIR method in two phases. And mice were sacrificed to extracting major organs and tumors, using ex vivo γ-counting as a reference. Strikingly, we observed that the image quality and the correlation between the all quantitive data from clinical PET/CT and the ex vivo counting was better with the SharpIR reconstructions than without. Our data demonstrate that clinical PET/CT scanner with SharpIR reconstruction is a valuable tool for imaging small animals in preclinical cancer research, offering dynamic imaging parameters, good image quality and accurate data quatification.

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.

PET or PET-CT with cancer screening

International Nuclear Information System (INIS)

Wang Taisong; Zhao Jinhua; Song Jianhua

2007-01-01

At present, cancer screening remains a lot of debate in contemporary medical practice. Many constitutes have done a lot of experiments in cancer screening. The same version is that recommendations and decisions regarding cancer screening should be based on reliable data, not self- approbation. Now, some institutes advocate 18 F-FDG PET or 18 F-FDG PET-CT for cancer screening, here, discussed status quo, potential financial, radiation safety and statistical data in 18 F-FDG PET or 18 F-FDG PET- CT cancer screening. (authors)

PET / MRI vs. PET / CT. Indications Oncology

International Nuclear Information System (INIS)

Oliva González, Juan P.

2016-01-01

Hybrid techniques in Nuclear Medicine is currently a field in full development for diagnosis and treatment of various medical conditions. With the recent advent of PET / MRI much it speculated about whether or not it is superior to PET / CT especially in oncology. The Conference seeks to clarify this situation by dealing issues such as: State of the art technology PET / MRI; Indications Oncology; Some clinical cases. It concludes by explaining the oncological indications of both the real and current situation of the PET / MRI. (author)

PET/CT. Dose-escalated image fusion?

International Nuclear Information System (INIS)

Brix, G.; Beyer, T.

2005-01-01

Clinical studies demonstrate a gain in diagnostic accuracy by employing combined PET/CT instead of separate CT and PET imaging. However, whole-body PET/CT examinations result in a comparatively high radiation burden to patients and thus require a proper justification and optimization to avoid repeated exposure or over-exposure of patients. This review article summarizes relevant data concerning radiation exposure of patients resulting from the different components of a combined PET/CT examination and presents different imaging strategies that can help to balance the diagnostic needs and the radiation protection requirements. In addition various dose reduction measures are discussed, some of which can be adopted from CT practice, while others mandate modifications to the existing hard- and software of PET/CT systems. (orig.)

PET-MRI and multimodal cancer imaging

International Nuclear Information System (INIS)

Wang Taisong; Zhao Jinhua; Song Jianhua

2011-01-01

Multimodality imaging, specifically PET-CT, brought a new perspective into the fields of clinical imaging. Clinical cases have shown that PET-CT has great value in clinical diagnosis and experimental research. But PET-CT still bears some limitations. A major drawback is that CT provides only limited soft tissue contrast and exposes the patient to a significant radiation dose. MRI overcome these limitations, it has excellent soft tissue contrast, high temporal and spatial resolution and no radiation damage. Additionally, since MRI provides also functional information, PET-MRI will show a new direction of multimodality imaging in the future. (authors)

Statistical dynamic image reconstruction in state-of-the-art high-resolution PET

International Nuclear Information System (INIS)

Rahmim, Arman; Cheng, J-C; Blinder, Stephan; Camborde, Maurie-Laure; Sossi, Vesna

2005-01-01

Modern high-resolution PET is now more than ever in need of scrutiny into the nature and limitations of the imaging modality itself as well as image reconstruction techniques. In this work, we have reviewed, analysed and addressed the following three considerations within the particular context of state-of-the-art dynamic PET imaging: (i) the typical average numbers of events per line-of-response (LOR) are now (much) less than unity (ii) due to the physical and biological decay of the activity distribution, one requires robust and efficient reconstruction algorithms applicable to a wide range of statistics and (iii) the computational considerations in dynamic imaging are much enhanced (i.e., more frames to be stored and reconstructed). Within the framework of statistical image reconstruction, we have argued theoretically and shown experimentally that the sinogram non-negativity constraint (when using the delayed-coincidence and/or scatter-subtraction techniques) is especially expected to result in an overestimation bias. Subsequently, two schemes are considered: (a) subtraction techniques in which an image non-negativity constraint has been imposed and (b) implementation of random and scatter estimates inside the reconstruction algorithms, thus enabling direct processing of Poisson-distributed prompts. Both techniques are able to remove the aforementioned bias, while the latter, being better conditioned theoretically, is able to exhibit superior noise characteristics. We have also elaborated upon and verified the applicability of the accelerated list-mode image reconstruction method as a powerful solution for accurate, robust and efficient dynamic reconstructions of high-resolution data (as well as a number of additional benefits in the context of state-of-the-art PET)

Reliability of semiquantitative 18F-FDG PET parameters derived from simultaneous brain PET/MRI: A feasibility study

International Nuclear Information System (INIS)

Jena, Amarnath; Taneja, Sangeeta; Goel, Reema; Renjen, Pushpendranath; Negi, Pradeep

2014-01-01

Purpose: Simultaneous brain PET/MRI faces an important issue of validation of accurate MRI based attenuation correction (AC) method for precise quantitation of brain PET data unlike in PET/CT systems where the use of standard, validated CT based AC is routinely available. The aim of this study was to investigate the feasibility of evaluation of semiquantitative 18 F-FDG PET parameters derived from simultaneous brain PET/MRI using ultrashort echo time (UTE) sequences for AC and to assess their agreement with those obtained from PET/CT examination. Methods: Sixteen patients (age range 18–73 years; mean age 49.43 (19.3) years; 13 men 3 women) underwent simultaneous brain PET/MRI followed immediately by PET/CT. Quantitative analysis of brain PET images obtained from both studies was undertaken using Scenium v.1 brain analysis software package. Twenty ROIs for various brain regions were system generated and 6 semiquantitative parameters including maximum standardized uptake value (SUV max), SUV mean, minimum SUV (SUV min), minimum standard deviation (SD min), maximum SD (SD max) and SD from mean were calculated for both sets of PET data for each patient. Intra-class correlation coefficients (ICCs) were determined to assess agreement between the various semiquantitative parameters for the two PET data sets. Results: Intra-class co-relation between the two PET data sets for SUV max, SUV mean and SD max was highly significant (p < 0.00) for all the 20 predefined brain regions with ICC > 0.9. SD from mean was also found to be statistically significant for all the predefined brain regions with ICC > 0.8. However, SUV max and SUV mean values obtained from PET/MRI were significantly lower compared to those of PET/CT for all the predefined brain regions. Conclusion: PET quantitation accuracy using the MRI based UTE sequences for AC in simultaneous brain PET/MRI is reliable in a clinical setting, being similar to that obtained using PET/CT

PET/CT in lymphoma patients; PET-CT bei Lymphompatienten

Energy Technology Data Exchange (ETDEWEB)

Steinert, H.C. [Universitaetsspital Zuerich, Klinik und Poliklinik fuer Nuklearmedizin (Switzerland)

2004-11-01

First results of PET/CT in Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) are reported. From March 2001 to August 2004 822 PET/CT were performed at our clinic in lymphoma patients for primary staging, restaging after therapy, and diagnosis of recurrence. For coregistration non contrast-enhanced low-dose CT were used. Due to the exact anatomic localization of {sup 18}F-FDG accumulating lesions equivocal or false positive PET findings are avoided. In comparison to contrast enhanced CT, PET/CT has a higher sensitivity and specificity in patients with HD and aggressive NHL. Integration of PET/CT in treatment planning of radiation therapy optimizes the field volume. Even in the initial phase of clinical evaluation, PET/CT has proven useful in staging and restaging of lymphoma. The exact anatomic localization of the PET findings is essential for a precise report, for treatment planning of radiation therapy, and for planning surgical biopsy. (orig.) [German] Erste Ergebnisse der PET-CT bei Morbus Hodgkin (HD) und den aggressiven Non-Hodgkin-Lymphomen (NHL) werden beschrieben. Von Maerz 2001 bis August 2004 wurden 822 PET-CT bei Lymphompatienten zum primaeren Staging, zum Restaging nach Therapie und zur Rezidivdiagnostik an unserer Klinik durchgefuehrt. Fuer die Koregistration wurde ein Low-dose-CT ohne i.v.-Kontrastmittel verwendet. Durch die exakte anatomische Zuordnung der {sup 18}F-FDG aufnehmenden Laesionen wurden unklare oder falsch-positive PET-Befunde vermieden. Die PET-CT erzielte im Vergleich zur KM-verstaerkten CT eine hoehere Sensitivitaet und Spezifitaet bei Patienten mit HD und aggressiven NHL. Die Integration der PET-CT in die Planung der Strahlentherapie fuehrte zu einer Optimierung der Feldgrenzen. Die PET-CT hat sich bereits in der Phase der initialen klinischen Evaluation als wertvoll beim Staging und Restaging von Lymphomen erwiesen. Die exakte anatomische Zuordnung der PET-Informationen ist fuer eine sichere Befundung

Low-dose respiratory-gated PET/CT: based on 30 mA tube current

International Nuclear Information System (INIS)

Wu Ping; Li Sijin; Zhang Yanlan; Hao Xinzhong; Qin Zhixing; Yan Min; Cheng Pengliang; Wu Zhifang

2013-01-01

Objective: To establish a low-dose but image-comparable respiratory-gated PET/CT (RG PET/CT) protocol based on 30 mA tube current plus other improved scanning parameters, such as the tube current, the number of respiratory phase and length of breathing cycle. Methods: Twenty-six patients with 18 F-FDG-intaking lung nodules underwent one-bed standard-dose PET/CT (120 mA, 2 min/bed) and low dose RG PET/CT (30 mA, 6 respiratory phases, 1 min/phase). The radiation dose and image quality were analyzed subsequently with signal to noise ratio (SNR) for PET and the homogeneity, noise level for CT in the water phantom respectively. Otherwise the CT images were both visual evaluated by two experienced doctors. In addition, different respiratory cycle was simulated to observe its relation with radiation dose. Results: The effective dose of low-dose RG PET/CT was 4.88∼7.69 mSv [mean (5.68±0.83) mSv]. The PET SNR showed no significance between groups. The homogeneity of 30 mA is good (< 5 HU), although noise level was high, the visual character like lobulation, speculation of lung nodule was superior in some respiratory phases. The radiation dose was positively correlated with respiratory cycle. Conclusions: The performance of low-dose RG PET/CT was comparable to those of standard-dose PET/CT based on a protocol with 30 mA tube current, 6 respiratory phases and breathing state of eupnoea. It produced a much lower radiation exposure and the image quality was enough for clinical use such as delineation of tumor active target, characterization and staging of lung nodules, etc. (authors)

Quantitative assessment of human and pet exposure to Salmonella associated with dry pet foods.

Science.gov (United States)

Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Ford, Randall M; Baker, Robert C; Pradhan, Abani K

2016-01-04

Recent Salmonella outbreaks associated with dry pet foods and treats highlight the importance of these foods as previously overlooked exposure vehicles for both pets and humans. In the last decade efforts have been made to raise the safety of this class of products, for instance by upgrading production equipment, cleaning protocols, and finished product testing. However, no comprehensive or quantitative risk profile is available for pet foods, thus limiting the ability to establish safety standards and assess the effectiveness of current and proposed Salmonella control measures. This study sought to develop an ingredients-to-consumer quantitative microbial exposure assessment model to: 1) estimate pet and human exposure to Salmonella via dry pet food, and 2) assess the impact of industry and household-level mitigation strategies on exposure. Data on prevalence and concentration of Salmonella in pet food ingredients, production process parameters, bacterial ecology, and contact transfer in the household were obtained through literature review, industry data, and targeted research. A probabilistic Monte Carlo modeling framework was developed to simulate the production process and basic household exposure routes. Under the range of assumptions adopted in this model, human exposure due to handling pet food is null to minimal if contamination occurs exclusively before extrusion. Exposure increases considerably if recontamination occurs post-extrusion during coating with fat, although mean ingested doses remain modest even at high fat contamination levels, due to the low percent of fat in the finished product. Exposure is highly variable, with the distribution of doses ingested by adult pet owners spanning 3Log CFU per exposure event. Child exposure due to ingestion of 1g of pet food leads to significantly higher doses than adult doses associated with handling the food. Recontamination after extrusion and coating, e.g., via dust or equipment surfaces, may also lead to

A comparison of reactive plasma pre-treatments on PET substrates by Cu and Ti pulsed-DC and HIPIMS discharges

Energy Technology Data Exchange (ETDEWEB)

Audronis, M., E-mail: m.audronis@yahoo.co.uk [Gencoa Ltd, Physics Road, Speke, Liverpool, L24 9HP (United Kingdom); Hinder, S.J. [The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH (United Kingdom); Mack, P. [ThermoFisher Scientific Ltd, Imberhorne Lane, East Grinstead, Sussex, RH19 1UB (United Kingdom); Bellido-Gonzalez, V. [Gencoa Ltd, Physics Road, Speke, Liverpool, L24 9HP (United Kingdom); Bussey, D.; Matthews, A. [Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD (United Kingdom); Baker, M.A. [The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH (United Kingdom)

2011-12-30

PET web samples have been treated by magnetically enhanced glow discharges powered using either medium frequency pulse direct current (p-DC) or low frequency high power pulse (HIPIMS) sources. The plasma pre-treatment processes were carried out in an Ar-O{sub 2} atmosphere using either Cu or Ti sputter targets. XPS, AFM and sessile drop water contact angle measurements have been employed to examine changes in surface chemistry and morphology for different pre-treatment process parameters. Deposition of metal oxide onto the PET surface is observed as a result of the sputter magnetron-based glow discharge web treatment. Using the Cu target, both the p-DC and HIPIMS processes result in the formation of a thin CuO layer (with a thickness between 1 and 11 nm) being deposited onto the PET surface. Employing the Ti target, both p-DC and HIPIMS processes give rise to a much lower concentration of Ti (< 5 at.%), in the form of TiO{sub 2} on the PET treated surface. The TiO{sub 2} is probably distributed as an island-like distribution covering the PET surface. Presence of Cu and Ti oxide constituents on the treated PET is beneficial in aiding the adhesion but alone (i.e. without oxygen plasma activation) is not enough to provide very high levels of hydrophilicity as is clear from sessile drop water contact angle measurements on aged samples. Exposure to the plasma treatments leads to a small amount of roughening of the substrate surface, but the average surface roughness in all cases is below 2.5 nm. The PET structure at the interface with a coating is mostly or wholly preserved. The oxygen plasma treatment, metal oxide deposition and surface roughening resulting from the HIPIMS and p-DC treatments will promote adhesion to any subsequent thin film that is deposited immediately following the plasma treatment.

Interpretation criteria for FDG PET/CT in multiple myeloma (IMPeTUs): final results. IMPeTUs (Italian myeloma criteria for PET USe).

Science.gov (United States)

Nanni, Cristina; Versari, Annibale; Chauvie, Stephane; Bertone, Elisa; Bianchi, Andrea; Rensi, Marco; Bellò, Marilena; Gallamini, Andrea; Patriarca, Francesca; Gay, Francesca; Gamberi, Barbara; Ghedini, Pietro; Cavo, Michele; Fanti, Stefano; Zamagni, Elena

2018-05-01

ᅟ: FDG PET/CT ( 18 F-fluoro-deoxy-glucose positron emission tomography/computed tomography) is a useful tool to image multiple myeloma (MM). However, simple and reproducible reporting criteria are still lacking and there is the need for harmonization. Recently, a group of Italian nuclear medicine experts defined new visual descriptive criteria (Italian Myeloma criteria for Pet Use: IMPeTUs) to standardize FDG PET/CT evaluation in MM patients. The aim of this study was to assess IMPeTUs reproducibility on a large prospective cohort of MM patients. Patients affected by symptomatic MM who had performed an FDG PET/CT at baseline (PET0), after induction (PET-AI), and the end of treatment (PET-EoT) were prospectively enrolled in a multicenter trial (EMN02)(NCT01910987; MMY3033). After anonymization, PET images were uploaded in the web platform WIDEN® and hence distributed to five expert nuclear medicine reviewers for a blinded independent central review according to the IMPeTUs criteria. Consensus among reviewers was measured by the percentage of agreement and the Krippendorff's alpha. Furthermore, on a patient-based analysis, the concordance among all the reviewers in terms of positivity or negativity of the FDG PET/CT scan was tested for different thresholds of positivity (Deauville score (DS 2, 3, 4, 5) for the main parameters (bone marrow, focal score, extra-medullary disease). Eighty-six patients (211 FDG PET/CT scans) were included in this analysis. Median patient age was 58 years (range, 35-66 years), 45% were male, 15% of them were in stage ISS (International Staging System) III, and 42% had high-risk cytogenetics. The percentage agreement was superior to 75% for all the time points, reaching 100% of agreement in assessing the presence skull lesions after therapy. Comparable results were obtained when the agreement analysis was performed using the Krippendorff's alpha coefficient, either in every single time point of scanning (PET0, PET-AI or PET-EoT) or

Advances in prostate-specific membrane antigen PET of prostate cancer.

Science.gov (United States)

Bouchelouche, Kirsten; Choyke, Peter L

2018-05-01

In recent years, a large number of reports have been published on prostate-specific membrane antigen (PSMA)/PET in prostate cancer (PCa). This review highlights advances in PSMA PET in PCa during the past year. PSMA PET/computed tomography (CT) is useful in detection of biochemical recurrence, especially at low prostate-specific antigen (PSA) values. The detection rate of PSMA PET is influenced by PSA level. For primary PCa, PSMA PET/CT shows promise for tumour localization in the prostate, especially in combination with multiparametric MRI (mpMRI). For primary staging, PSMA PET/CT can be used in intermediate and high-risk PCa. Intraoperative PSMA radioligand guidance seems promising for detection of malignant lymph nodes. While the use of PSMA PET/MRI in primary localized disease is limited to high and intermediate-risk patients and localized staging, in the recurrence setting, PET/MRI can be particularly helpful when the lesions are subtle. PSMA PET/CT is superior to choline PET/CT and other conventional imaging modalities. Molecular imaging with PSMA PET continues to pave the way for personalized medicine in PCa.However, large prospective clinical studies are still needed to fully evaluate the role of PSMA PET/CT and PET/MRI in the clinical workflow of PCa.

Novel Geometrical Concept of a High Performance Brain PET Scanner Principle, Design and Performance Estimates

CERN Document Server

Séguinot, Jacques; Chesi, Enrico Guido; Joram, C; Mathot, S; Weilhammer, P; Chamizo-Llatas, M; Correia, J G; Ribeiro da Silva, M; Garibaldi, F; De Leo, R; Nappi, E; Corsi, F; Dragone, A; Schoenahl, F; Zaidi, H

2006-01-01

We present the principle, a possible implementation and performance estimates of a novel geometrical concept for a high resolution positron emission tomograph. The concept, which can for example be implemented in a brain PET device, promisses to lead to an essentially parallax free 3D image reconstruction with excellent spatial resolution and constrast, uniform over the complete field of view. The key components are matrices of long axially oriented scintillator crystals which are read out at both extremities by segmented Hybrid Photon Detectors. We discuss the relevant design considerations for a 3D axial PET camera module, motivate parameter and material choices, and estimate its performance in terms of spatial and energy resolution. We support these estimates by Monte Carlo simulations and in some cases by first experimental results. From the performance of a camera module, we extrapolate to the reconstruction resolution of a 3D axial PET scanner in a semi-analytical way and compare it to an existing state...

The relationship between myocardial blood flow and myocardial viability after reperfusion. Myocardial viability assessed by [sup 15]O-water-PET

Energy Technology Data Exchange (ETDEWEB)

Tsukagoshi, Joichi (Gunma Univ., Maebashi (Japan). School of Medicine)

1994-09-01

The purpose of this study was to examine the relationship between myocardial blood flow and myocardial viability in the ischemic canine myocardium after reperfusion. Transient ischemia was induced by 60-, 90-, and 180-minute occlusion of the left anterior descending coronary artery. Myocardial blood flow (MBF) was measured in the areas in which regional contractility was severely impaired (ehocardiographically akinetic or dyskinetic) in the early reperfusion period by [sup 15]O-water positron emission tomography (PET) 12 hours and 4 weeks after reperfusion. An MBF ratio of ischemic to nonischemic regions 12 hours after reperfusion was inversely correlated with the amount of histologically determined tissue necrosis (r=-0.74). The regional contractility recovered 4 weeks later in the areas where an MBF ratio was 0.48 or greater, but did not recover in the areas with a lower MBF ratio. Thus, myocardial viability can be appropriately predicted in the early phase of myocardial perfusion by PET with [sup 15]O-water even in the absence of metabolic imaging. (author).

Evaluation of PET performance and MR compatibility of a preclinical PET/MR insert with digital silicon photomultiplier technology

Energy Technology Data Exchange (ETDEWEB)

Hallen, Patrick; Schug, David; Wehner, Jakob [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany); Weissler, Bjorn [Department of Chemical Application Research, Philips Research (Germany); Gebhardt, Pierre [Division of Imaging Sciences and Biomedical Engineering, King’s College London (United Kingdom); Goldschmidt, Benjamin [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany); Salomon, Andre [Department of Oncology Solutions, Philips Research (Germany); Duppenbecker, Peter [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany); Kiessling, Fabian [Institute for Experimental Molecular Imaging, RWTH Aachen University (Germany); Schultz, Volkmar [Department of Physics of Molecular Imaging Systems, RWTH Aachen University (Germany)

2015-05-18

In this work we present detailed characterizations of our preclinical high resolution PET/MR insert based on the Hyperion-IID platform. The PET/MR insert consists of a ring of 10 singles detection modules, each comprising 2x3 scintillation detector stacks. Each detector stack features a 30x30 pixelated LYSO crystal array with a height of 12 mm and a pitch of 1 mm, coupled via a slit 2 mm light guide to a digital SiPM tile. The PET performance is stable under a wide range of operating points. The spatial resolution is below 1Ä,mm and the CRT reaches 260 or 450 ps depending on trigger settings. The energy resolution is 12.6% FWHM. The characterization of the MR compatibility showed no relevant degradation in PET performance during MRI operation. On the MRI side, we observe a degradation in B0 homogeneity from a VRMS of 0.03 ppm to 0.08 ppm with active shimming, while observing only minor degradations in the B0 field. The noise floor is slightly increased by 2-15% without any observable dependence on the activity. The Z gradients induces an observable eddy current inside the PET inserts which can lead to ghosting artifacts for EPI sequences. However, we don't observe any visible image degradation for widely used anatomical imaging sequences such as gradient echo and turbo spin echo sequences. To prove the viability of our PET/MR insert for in vivo small animal studies, we successfully performed a longitudinal mouse study with subcutaneously injected tumor model cells. The simultaneously acquired PET/MR images provide a high level of anatomical information and soft tissue contrast in the MR layer together with a high resolution image of the FDG tracer distribution in the PET layer.

Evaluation of high performance data acquisition boards for simultaneous sampling of fast signals from PET detectors

International Nuclear Information System (INIS)

Judenhofer, Martin S; Pichler, Bernd J; Cherry, Simon R

2005-01-01

Detectors used for positron emission tomography (PET) provide fast, randomly distributed signals that need to be digitized for further processing. One possibility is to sample the signals at the peak initiated by a trigger from a constant fraction discriminator (CFD). For PET detectors, simultaneous acquisition of many channels is often important. To develop and evaluate novel PET detectors, a flexible, relatively low cost and high performance laboratory data acquisition (DAQ) system is therefore required. The use of dedicated DAQ systems, such as a multi-channel analysers (MCAs) or continuous sampling boards at high rates, is expensive. This work evaluates the suitability of well-priced peripheral component interconnect (PCI)-based 8-channel DAQ boards (PD2-MFS-8 2M/14 and PD2-MFS-8-500k/14, United Electronic Industries Inc., Canton, MA, USA) for signal acquisition from novel PET detectors. A software package was developed to access the board, measure basic board parameters, and to acquire, visualize, and analyse energy spectra and position profiles from block detectors. The performance tests showed that the boards input linearity is >99.2% and the standard deviation is 22 Na source was 14.9% (FWHM) at 511 keV and is slightly better than the result obtained with a high-end single channel MCA (8000A, Amptek, USA) using the same detector (16.8%). The crystals (1.2 x 1.2 x 12 mm 3 ) within a 9 x 9 LSO block detector could be clearly separated in an acquired position profile. Thus, these boards are well suited for data acquisition with novel detectors developed for nuclear imaging

An ASIC implementation of digital front-end electronics for a high resolution PET scanner

International Nuclear Information System (INIS)

Newport, D.F.; Young, J.W.

1993-01-01

AN Application Specific Integrated Circuit (ASIC) has been designed and fabricated which implements many of the current functions found in the digital front-end electronics for a high resolution Positron Emission Tomography (PET) scanner. The ASIC performs crystal selection, energy qualification, time correction, and event counting functions for block technology high resolution PET scanners. Digitized x and y position, event energy, and time information are used by the ASIC to determine block crystal number, qualify the event based on energy, and correct the event time. In addition, event counting and block dead time calculations are performed for system dead time corrections. A loadable sequencer for controlling the analog front-end electronics is also implemented. The ASIC is implemented in a 37,000 gate, 1.0 micron CMOS gate-array and is capable of handling 4 million events/second while reducing parts count, cost, and power consumption over current board-level designs

[Principles of PET].

Science.gov (United States)

Beuthien-Baumann, B

2018-05-01

Positron emission tomography (PET) is a procedure in nuclear medicine, which is applied predominantly in oncological diagnostics. In the form of modern hybrid machines, such as PET computed tomography (PET/CT) and PET magnetic resonance imaging (PET/MRI) it has found wide acceptance and availability. The PET procedure is more than just another imaging technique, but a functional method with the capability for quantification in addition to the distribution pattern of the radiopharmaceutical, the results of which are used for therapeutic decisions. A profound knowledge of the principles of PET including the correct indications, patient preparation, and possible artifacts is mandatory for the correct interpretation of PET results.

Additive value of amyloid-PET in routine cases of clinical dementia work-up after FDG-PET

International Nuclear Information System (INIS)

Brendel, Matthias; Schnabel, Jonas; Wagner, Leonie; Brendel, Eva; Meyer-Wilmes, Johanna; Unterrainer, Marcus; Schoenecker, Sonja; Prix, Catharina; Ackl, Nibal; Schildan, Andreas; Patt, Marianne; Barthel, Henryk; Sabri, Osama; Catak, Cihan; Pogarell, Oliver; Levin, Johannes; Danek, Adrian; Buerger, Katharina; Bartenstein, Peter; Rominger, Axel

2017-01-01

In recent years, several [ 18 F]-labeled amyloid-PET tracers have been developed and have obtained clinical approval. Despite their widespread scientific use, studies in routine clinical settings are limited. We therefore investigated the impact of [ 18 F]-florbetaben (FBB)-PET on the diagnostic management of patients with suspected dementia that was still unclarified after [ 18 F]-fluordeoxyglucose (FDG)-PET. All subjects were referred in-house with a suspected dementia syndrome due to neurodegenerative disease. After undergoing an FDG-PET exam, the cases were discussed by the interdisciplinary dementia board, where the most likely diagnosis as well as potential differential diagnoses were documented. Because of persistent diagnostic uncertainty, the patients received an additional FBB-PET exam. Results were interpreted visually and classified as amyloid-positive or amyloid-negative, and we then compared the individual clinical diagnoses before and after additional FBB-PET. A total of 107 patients (mean age 69.4 ± 9.7y) were included in the study. The FBB-PET was rated as amyloid-positive in 65/107. In 83% of the formerly unclear cases, a final diagnosis was reached through FBB-PET, and the most likely prior diagnosis was changed in 28% of cases. The highest impact was observed for distinguishing Alzheimer's dementia (AD) from fronto-temporal dementia (FTLD), where FBB-PET altered the most likely diagnosis in 41% of cases. FBB-PET has a high additive value in establishing a final diagnosis in suspected dementia cases when prior investigations such as FDG-PET are inconclusive. The differentiation between AD and FTLD was particularly facilitated by amyloid-PET, predicting a considerable impact on patient management, especially in the light of upcoming disease-modifying therapies. (orig.)

Additive value of amyloid-PET in routine cases of clinical dementia work-up after FDG-PET

Energy Technology Data Exchange (ETDEWEB)

Brendel, Matthias; Schnabel, Jonas; Wagner, Leonie; Brendel, Eva; Meyer-Wilmes, Johanna; Unterrainer, Marcus [University Hospital, LMU Munich, Department of Nuclear Medicine, Munich (Germany); Schoenecker, Sonja; Prix, Catharina; Ackl, Nibal [University Hospital, LMU Munich, Department of Neurology, Munich (Germany); Schildan, Andreas; Patt, Marianne; Barthel, Henryk; Sabri, Osama [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Catak, Cihan [Klinikum der Universitaet Muenchen, Institute for Stroke and Dementia Research, Munich (Germany); Pogarell, Oliver [University Hospital, LMU Munich, Department of Psychiatry, Munich (Germany); Levin, Johannes; Danek, Adrian [University Hospital, LMU Munich, Department of Neurology, Munich (Germany); DZNE - German Center for Neurodegenerative Diseases, Munich (Germany); Buerger, Katharina [Klinikum der Universitaet Muenchen, Institute for Stroke and Dementia Research, Munich (Germany); DZNE - German Center for Neurodegenerative Diseases, Munich (Germany); Bartenstein, Peter; Rominger, Axel [University Hospital, LMU Munich, Department of Nuclear Medicine, Munich (Germany); Munich Cluster for Systems Neurology (SyNergy), Munich (Germany)

2017-12-15

In recent years, several [{sup 18}F]-labeled amyloid-PET tracers have been developed and have obtained clinical approval. Despite their widespread scientific use, studies in routine clinical settings are limited. We therefore investigated the impact of [{sup 18}F]-florbetaben (FBB)-PET on the diagnostic management of patients with suspected dementia that was still unclarified after [{sup 18}F]-fluordeoxyglucose (FDG)-PET. All subjects were referred in-house with a suspected dementia syndrome due to neurodegenerative disease. After undergoing an FDG-PET exam, the cases were discussed by the interdisciplinary dementia board, where the most likely diagnosis as well as potential differential diagnoses were documented. Because of persistent diagnostic uncertainty, the patients received an additional FBB-PET exam. Results were interpreted visually and classified as amyloid-positive or amyloid-negative, and we then compared the individual clinical diagnoses before and after additional FBB-PET. A total of 107 patients (mean age 69.4 ± 9.7y) were included in the study. The FBB-PET was rated as amyloid-positive in 65/107. In 83% of the formerly unclear cases, a final diagnosis was reached through FBB-PET, and the most likely prior diagnosis was changed in 28% of cases. The highest impact was observed for distinguishing Alzheimer's dementia (AD) from fronto-temporal dementia (FTLD), where FBB-PET altered the most likely diagnosis in 41% of cases. FBB-PET has a high additive value in establishing a final diagnosis in suspected dementia cases when prior investigations such as FDG-PET are inconclusive. The differentiation between AD and FTLD was particularly facilitated by amyloid-PET, predicting a considerable impact on patient management, especially in the light of upcoming disease-modifying therapies. (orig.)

MR-assisted PET motion correction in simultaneous PET/MRI studies of dementia subjects.

Science.gov (United States)

Chen, Kevin T; Salcedo, Stephanie; Chonde, Daniel B; Izquierdo-Garcia, David; Levine, Michael A; Price, Julie C; Dickerson, Bradford C; Catana, Ciprian

2018-03-08

Subject motion in positron emission tomography (PET) studies leads to image blurring and artifacts; simultaneously acquired magnetic resonance imaging (MRI) data provides a means for motion correction (MC) in integrated PET/MRI scanners. To assess the effect of realistic head motion and MR-based MC on static [ 18 F]-fluorodeoxyglucose (FDG) PET images in dementia patients. Observational study. Thirty dementia subjects were recruited. 3T hybrid PET/MR scanner where EPI-based and T 1 -weighted sequences were acquired simultaneously with the PET data. Head motion parameters estimated from high temporal resolution MR volumes were used for PET MC. The MR-based MC method was compared to PET frame-based MC methods in which motion parameters were estimated by coregistering 5-minute frames before and after accounting for the attenuation-emission mismatch. The relative changes in standardized uptake value ratios (SUVRs) between the PET volumes processed with the various MC methods, without MC, and the PET volumes with simulated motion were compared in relevant brain regions. The absolute value of the regional SUVR relative change was assessed with pairwise paired t-tests testing at the P = 0.05 level, comparing the values obtained through different MR-based MC processing methods as well as across different motion groups. The intraregion voxelwise variability of regional SUVRs obtained through different MR-based MC processing methods was also assessed with pairwise paired t-tests testing at the P = 0.05 level. MC had a greater impact on PET data quantification in subjects with larger amplitude motion (higher than 18% in the medial orbitofrontal cortex) and greater changes were generally observed for the MR-based MC method compared to the frame-based methods. Furthermore, a mean relative change of ∼4% was observed after MC even at the group level, suggesting the importance of routinely applying this correction. The intraregion voxelwise variability of regional SUVRs

High performance hydrophilic pervaporation composite membranes for water desalination

KAUST Repository

Liang, Bin

2014-08-01

A three-layer thin film nanofibrous pervaporation composite (TFNPVC) membrane was prepared by sequential deposition using electrospraying/electrospinning. The poly(vinyl alcohol) (PVA) top barrier layer was first electrosprayed on aluminum foil and its thickness can be easily controlled by adjusting the collecting time. Next a polyacrylonitrile (PAN) nanofibrous scaffold was deposited by electrospinning as a mid-layer support. A nonwoven PET layer is used to complete the composite membrane. The pervaporation desalination performance of TFNPVC membranes was tested using NaCl solutions at 100. Pa and at room temperature. The TFNPVC membranes show excellent desalination performance (high water flux and salt rejection >. 99.5%) for different salt concentrations with virtually no change in performance after 50. h of operation. © 2014 Elsevier B.V.

Textural analysis of pre-therapeutic [18F]-FET-PET and its correlation with tumor grade and patient survival in high-grade gliomas

Energy Technology Data Exchange (ETDEWEB)

Pyka, Thomas; Hiob, Daniela; Wester, Hans-Juergen [Klinikum Rechts der Isar der TU Muenchen, Department of Nuclear Medicine, Munich (Germany); Gempt, Jens; Ringel, Florian; Meyer, Bernhard [Klinikum Rechts der Isar der TU Muenchen, Neurosurgic Department, Munich (Germany); Schlegel, Juergen [Klinikum Rechts der Isar der TU Muenchen, Institute of Pathology and Neuropathology, Munich (Germany); Bette, Stefanie [Klinikum Rechts der Isar der TU Muenchen, Neuroradiologic department, Munich (Germany); Foerster, Stefan [Klinikum Rechts der Isar der TU Muenchen, Department of Nuclear Medicine, Munich (Germany); Klinikum Rechts der Isar der TU Muenchen, TUM Neuroimaging Center (TUM-NIC), Munich (Germany)

2016-01-15

Amino acid positron emission tomography (PET) with [18F]-fluoroethyl-L-tyrosine (FET) is well established in the diagnostic work-up of malignant brain tumors. Analysis of FET-PET data using tumor-to-background ratios (TBR) has been shown to be highly valuable for the detection of viable hypermetabolic brain tumor tissue; however, it has not proven equally useful for tumor grading. Recently, textural features in 18-fluorodeoxyglucose-PET have been proposed as a method to quantify the heterogeneity of glucose metabolism in a variety of tumor entities. Herein we evaluate whether textural FET-PET features are of utility for grading and prognostication in patients with high-grade gliomas. One hundred thirteen patients (70 men, 43 women) with histologically proven high-grade gliomas were included in this retrospective study. All patients received static FET-PET scans prior to first-line therapy. TBR (max and mean), volumetric parameters and textural parameters based on gray-level neighborhood difference matrices were derived from static FET-PET images. Receiver operating characteristic (ROC) and discriminant function analyses were used to assess the value for tumor grading. Kaplan-Meier curves and univariate and multivariate Cox regression were employed for analysis of progression-free and overall survival. All FET-PET textural parameters showed the ability to differentiate between World Health Organization (WHO) grade III and IV tumors (p < 0.001; AUC 0.775). Further improvement in discriminatory power was possible through a combination of texture and metabolic tumor volume, classifying 85 % of tumors correctly (AUC 0.830). TBR and volumetric parameters alone were correlated with tumor grade, but showed lower AUC values (0.644 and 0.710, respectively). Furthermore, a correlation of FET-PET texture but not TBR was shown with patient PFS and OS, proving significant in multivariate analysis as well. Volumetric parameters were predictive for OS, but this correlation did not

Quantification of myocardial blood flow with dynamic perfusion 3.0 Tesla MRI: Validation with (15) O-water PET.

Science.gov (United States)

Tomiyama, Yuuki; Manabe, Osamu; Oyama-Manabe, Noriko; Naya, Masanao; Sugimori, Hiroyuki; Hirata, Kenji; Mori, Yuki; Tsutsui, Hiroyuki; Kudo, Kohsuke; Tamaki, Nagara; Katoh, Chietsugu

2015-09-01

To develop and validate a method for quantifying myocardial blood flow (MBF) using dynamic perfusion magnetic resonance imaging (MBFMRI ) at 3.0 Tesla (T) and compare the findings with those of (15) O-water positron emission tomography (MBFPET ). Twenty healthy male volunteers underwent magnetic resonance imaging (MRI) and (15) O-water positron emission tomography (PET) at rest and during adenosine triphosphate infusion. The single-tissue compartment model was used to estimate the inflow rate constant (K1). We estimated the extraction fraction of Gd-DTPA using K1 and MBF values obtained from (15) O-water PET for the first 10 subjects. For validation, we calculated MBFMRI values for the remaining 10 subjects and compared them with the MBFPET values. In addition, we compared MBFMRI values of 10 patients with coronary artery disease with those of healthy subjects. The mean resting and stress MBFMRI values were 0.76 ± 0.10 and 3.04 ± 0.82 mL/min/g, respectively, and showed excellent correlation with the mean MBFPET values (r = 0.96, P < 0.01). The mean stress MBFMRI value was significantly lower for the patients (1.92 ± 0.37) than for the healthy subjects (P < 0.001). The use of dynamic perfusion MRI at 3T is useful for estimating MBF and can be applied for patients with coronary artery disease. © 2014 Wiley Periodicals, Inc.

FDG-PET in Follicular Lymphoma Management

Directory of Open Access Journals (Sweden)

C. Bodet-Milin

2012-01-01

Full Text Available 18-Fluoro-deoxyglucose positron emission tomography/computerised tomography (FDG PET/CT is commonly used in the management of patients with lymphomas and is recommended for both initial staging and response assessment after treatment in patients with diffuse large B-cell lymphoma and Hodgkin lymphoma. Despite the FDG avidity of follicular lymphoma (FL, FDG PET/CT is not yet applied in standard clinical practice for patients with FL. However, FDG PET/CT is more accurate than conventional imaging for initial staging, often prompting significant management change, and allows noninvasive characterization to guide assessment of high-grade transformation. For restaging, FDG PET/CT assists in distinguishing between scar tissue and viable tumors in residual masses and a positive PET after induction treatment would seem to predict a shorter progression-free survival.

A Movable Phantom Design for Quantitative Evaluation of Motion Correction Studies on High Resolution PET Scanners

DEFF Research Database (Denmark)

Olesen, Oline Vinter; Svarer, C.; Sibomana, M.

2010-01-01

maximization algorithm with modeling of the point spread function (3DOSEM-PSF), and they were corrected for motions based on external tracking information using the Polaris Vicra real-time stereo motion-tracking system. The new automatic, movable phantom has a robust design and is a potential quality......Head movements during brain imaging using high resolution positron emission tomography (PET) impair the image quality which, along with the improvement of the spatial resolution of PET scanners, in general, raises the importance of motion correction. Here, we present a new design for an automatic...

Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

Science.gov (United States)

Wu, T.-H.; Liang, C.-H.; Wu, J.-K.; Lien, C.-Y.; Yang, B.-H.; Huang, Y.-H.; Lee, J. J. S.

2009-07-01

Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of 18F-fluorodeoxyglucose (18F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT may have a

Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

International Nuclear Information System (INIS)

Wu, T-H; Liang, C-H; Wu, J-K; Lien, C-Y; Yang, B-H; Lee, J J S; Huang, Y-H

2009-01-01

Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of 18 F-fluorodeoxyglucose ( 18 F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT may have a

Relevance of positron emission tomography (PET) in oncology

International Nuclear Information System (INIS)

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

1999-01-01

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

SiliPET: An ultra high resolution design of a small animal PET scanner based on double sided silicon strip detector stacks

International Nuclear Information System (INIS)

Zavattini, G.; Cesca, N.; Di Domenico, G.; Moretti, E.; Sabba, N.

2006-01-01

We investigated the capabilities of a small animal PET scanner, named SiliPET, based on four stacks of double sided silicon strips detectors. Each stack consists of 40 silicon detectors with dimension 60x60x1mm 3 . These are arranged to form a box 5x5x6cm 3 with minor sides opened; the box represents the maximal FOV of the scanner. The performance parameters of SiliPET scanner have been estimated, giving an intrinsic spatial resolution of 0.52mm and a sensitivity of 5.1% at the center of the system

CNS metabolism in high-risk drug abuse, German version. Insights gained from "1H- and "3"1P MRS and PET

International Nuclear Information System (INIS)

Bodea, S.V.

2017-01-01

High-risk drug consumption is a considerable problem for public health actors in industrialised countries. The latest trends show a market tendency towards diversification and increasing demand for high-purity synthetic drugs. Whilst most consumers seek medical help after cannabis use, it is high-risk drugs like cocaine, heroin and amphetamines that account for most of the 1000 drug-related deaths that occur in Germany every year. This article presents the most prominent in vivo cerebral metabolic information in cocaine, heroin and methamphetamine users provided by MRI spectroscopy and PET imaging. We reviewed the literature reporting neuroimaging studies of in vivo metabolic data for methamphetamine, cocaine and heroin consumption published up to March 2017. The search was conducted using PubMed with the following key words: methamphetamine, cocaine, heroin, MR spectroscopy, PET. MRI and PET are indispensable tools in gauging brain metabolic response to illegal drug abuse. Future breakthroughs in this field will most likely come from the investigation of novel neurotransmitter systems in PET and imaging phosphorus and carbon metabolites in MRI. (orig.) [de

Prediction of standard-dose brain PET image by using MRI and low-dose brain [{sup 18}F]FDG PET images

Energy Technology Data Exchange (ETDEWEB)

Kang, Jiayin [School of Electronics Engineering, Huaihai Institute of Technology, Lianyungang, Jiangsu 222005, China and IDEA Laboratory, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Gao, Yaozong [IDEA Laboratory, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Shi, Feng [IDEA Laboratory, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Lalush, David S. [Joint UNC-NCSU Department of Biomedical Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Lin, Weili [MRI Laboratory, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Shen, Dinggang, E-mail: dgshen@med.unc.edu [IDEA Laboratory, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 and Department of Brain and Cognitive Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

2015-09-15

Purpose: Positron emission tomography (PET) is a nuclear medical imaging technology that produces 3D images reflecting tissue metabolic activity in human body. PET has been widely used in various clinical applications, such as in diagnosis of brain disorders. High-quality PET images play an essential role in diagnosing brain diseases/disorders. In practice, in order to obtain high-quality PET images, a standard-dose radionuclide (tracer) needs to be used and injected into a living body. As a result, it will inevitably increase the patient’s exposure to radiation. One solution to solve this problem is predicting standard-dose PET images using low-dose PET images. As yet, no previous studies with this approach have been reported. Accordingly, in this paper, the authors propose a regression forest based framework for predicting a standard-dose brain [{sup 18}F]FDG PET image by using a low-dose brain [{sup 18}F]FDG PET image and its corresponding magnetic resonance imaging (MRI) image. Methods: The authors employ a regression forest for predicting the standard-dose brain [{sup 18}F]FDG PET image by low-dose brain [{sup 18}F]FDG PET and MRI images. Specifically, the proposed method consists of two main steps. First, based on the segmented brain tissues (i.e., cerebrospinal fluid, gray matter, and white matter) in the MRI image, the authors extract features for each patch in the brain image from both low-dose PET and MRI images to build tissue-specific models that can be used to initially predict standard-dose brain [{sup 18}F]FDG PET images. Second, an iterative refinement strategy, via estimating the predicted image difference, is used to further improve the prediction accuracy. Results: The authors evaluated their algorithm on a brain dataset, consisting of 11 subjects with MRI, low-dose PET, and standard-dose PET images, using leave-one-out cross-validations. The proposed algorithm gives promising results with well-estimated standard-dose brain [{sup 18}F]FDG PET

Prediction of standard-dose brain PET image by using MRI and low-dose brain ["1"8F]FDG PET images

International Nuclear Information System (INIS)

Kang, Jiayin; Gao, Yaozong; Shi, Feng; Lalush, David S.; Lin, Weili; Shen, Dinggang

2015-01-01

Purpose: Positron emission tomography (PET) is a nuclear medical imaging technology that produces 3D images reflecting tissue metabolic activity in human body. PET has been widely used in various clinical applications, such as in diagnosis of brain disorders. High-quality PET images play an essential role in diagnosing brain diseases/disorders. In practice, in order to obtain high-quality PET images, a standard-dose radionuclide (tracer) needs to be used and injected into a living body. As a result, it will inevitably increase the patient’s exposure to radiation. One solution to solve this problem is predicting standard-dose PET images using low-dose PET images. As yet, no previous studies with this approach have been reported. Accordingly, in this paper, the authors propose a regression forest based framework for predicting a standard-dose brain ["1"8F]FDG PET image by using a low-dose brain ["1"8F]FDG PET image and its corresponding magnetic resonance imaging (MRI) image. Methods: The authors employ a regression forest for predicting the standard-dose brain ["1"8F]FDG PET image by low-dose brain ["1"8F]FDG PET and MRI images. Specifically, the proposed method consists of two main steps. First, based on the segmented brain tissues (i.e., cerebrospinal fluid, gray matter, and white matter) in the MRI image, the authors extract features for each patch in the brain image from both low-dose PET and MRI images to build tissue-specific models that can be used to initially predict standard-dose brain ["1"8F]FDG PET images. Second, an iterative refinement strategy, via estimating the predicted image difference, is used to further improve the prediction accuracy. Results: The authors evaluated their algorithm on a brain dataset, consisting of 11 subjects with MRI, low-dose PET, and standard-dose PET images, using leave-one-out cross-validations. The proposed algorithm gives promising results with well-estimated standard-dose brain ["1"8F]FDG PET image and substantially

Lung PET scan

Science.gov (United States)

... Chest PET scan; Lung positron emission tomography; PET - chest; PET - lung; PET - tumor imaging; ... Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. Philadelphia, ...

Low-count PET image restoration using sparse representation

Science.gov (United States)

Li, Tao; Jiang, Changhui; Gao, Juan; Yang, Yongfeng; Liang, Dong; Liu, Xin; Zheng, Hairong; Hu, Zhanli

2018-04-01

In the field of positron emission tomography (PET), reconstructed images are often blurry and contain noise. These problems are primarily caused by the low resolution of projection data. Solving this problem by improving hardware is an expensive solution, and therefore, we attempted to develop a solution based on optimizing several related algorithms in both the reconstruction and image post-processing domains. As sparse technology is widely used, sparse prediction is increasingly applied to solve this problem. In this paper, we propose a new sparse method to process low-resolution PET images. Two dictionaries (D1 for low-resolution PET images and D2 for high-resolution PET images) are learned from a group real PET image data sets. Among these two dictionaries, D1 is used to obtain a sparse representation for each patch of the input PET image. Then, a high-resolution PET image is generated from this sparse representation using D2. Experimental results indicate that the proposed method exhibits a stable and superior ability to enhance image resolution and recover image details. Quantitatively, this method achieves better performance than traditional methods. This proposed strategy is a new and efficient approach for improving the quality of PET images.

In-beam PET measurement of $^{7}Li^{3+}$ irradiation induced $\\beta^+}$-activity

CERN Document Server

Priegnitz, M; Parodi, K; Sommerer, F; Fiedler, F; Enghardt, W

2008-01-01

At present positron emission tomography (PET) is the only feasible method of an in situ and non-invasive monitoring of patient irradiation with ions. At the experimental carbon ion treatment facility of the Gesellschaft für Schwerionenforschung (GSI) Darmstadt an in-beam PET scanner has been integrated into the treatment site and lead to a considerable quality improvement of the therapy. Since ions other than carbon are expected to come into operation in future patient treatment facilities, it is highly desirable to extend in-beam PET also to other therapeutic relevant ions, e.g. 7Li. Therefore, by means of the in-beam PET scanner at GSI the β+-activity induced by 7Li3+ ions has been investigated for the first time. Targets of PMMA, water, graphite and polyethylene were irradiated with monoenergetic, pencil-like beams of 7Li3+ with energies between 129.1 A MeV and 205.3 A MeV and intensities ranging from 3.0 × 107 to 1.9 × 108 ions s−1. This paper presents the measured β+-activity profiles as well as d...

Use of a clinical PET/MR scanner for preclinical research with first results

International Nuclear Information System (INIS)

Chary, Karthik; Teuho, Jarmo; Virta, Jenni; Sipilä, Hannu; Saunavaara, Virva; Roivainen, Anne; Teräs, Mika

2014-01-01

This study was performed to evaluate the feasibility of preclinical imaging in a clinical PET/MR system. Preliminary sequences were evaluated for establishing preclinical protocols for rat brain and rabbit knee. Rats were placed in a stereotactic holder, allowing a 30 minute scan time before re-administration of anesthesia. In-house developed warm-water heating system was used to maintain the body temperature at 37.5°C, monitored using an MR-compatible rectal probe. Brain imaging was performed with a dedicated 4 channel phased array receive coil (RAPID Biomedical GmbH, Germany). High resolution coronal images were acquired using conventional T1-SE (0.30x0.30x1.2mm) and T2-TSE (0.23x0.23x0.7mm) with a total scan time of 30 min. PET/MR imaging was performed on two white rabbits. The rabbits were imaged in a custom wooden holder. PET/MR protocol had a total duration of 45 minutes. No external heating was used. MR protocol consisted of anatomical T1, T2 and PDW of the knees, using a SENSE Flex-S coil. MR attenuation correction (MRAC) was acquired with 3D T1-FFE using three-class segmentation. A dynamic 30 minute PET acquisition was started on injection of 33.8MBq of Ga-68. Animal coils enabled high resolution images to be acquired in reasonable acquisition time with regards to animal handling and anesthesia. T1 and T2 images provided good differentiation of anatomy in the rat brain with high contrast. T1, T2 and PDW images of the rabbit knee had high resolution and differentiation of anatomical structures. MRAC was able to distinguish the knees and the body contour. Image fusion of PET and MR was able to localize the infection, which was confirmed by a physician. Pre-clinical imaging with the Ingenuity TF was deemed feasible, although PET imaging is limited by the resolution of the scanner. The preliminary sequences were successfully implemented for future studies on the Ingenuity TF.

Use of a clinical PET/MR scanner for preclinical research with first results

Energy Technology Data Exchange (ETDEWEB)

Chary, Karthik; Teuho, Jarmo; Virta, Jenni; Sipilä, Hannu; Saunavaara, Virva; Roivainen, Anne; Teräs, Mika [Turku PET Centre, Turku University Hospital, Turku (Finland)

2014-07-29

This study was performed to evaluate the feasibility of preclinical imaging in a clinical PET/MR system. Preliminary sequences were evaluated for establishing preclinical protocols for rat brain and rabbit knee. Rats were placed in a stereotactic holder, allowing a 30 minute scan time before re-administration of anesthesia. In-house developed warm-water heating system was used to maintain the body temperature at 37.5°C, monitored using an MR-compatible rectal probe. Brain imaging was performed with a dedicated 4 channel phased array receive coil (RAPID Biomedical GmbH, Germany). High resolution coronal images were acquired using conventional T1-SE (0.30x0.30x1.2mm) and T2-TSE (0.23x0.23x0.7mm) with a total scan time of 30 min. PET/MR imaging was performed on two white rabbits. The rabbits were imaged in a custom wooden holder. PET/MR protocol had a total duration of 45 minutes. No external heating was used. MR protocol consisted of anatomical T1, T2 and PDW of the knees, using a SENSE Flex-S coil. MR attenuation correction (MRAC) was acquired with 3D T1-FFE using three-class segmentation. A dynamic 30 minute PET acquisition was started on injection of 33.8MBq of Ga-68. Animal coils enabled high resolution images to be acquired in reasonable acquisition time with regards to animal handling and anesthesia. T1 and T2 images provided good differentiation of anatomy in the rat brain with high contrast. T1, T2 and PDW images of the rabbit knee had high resolution and differentiation of anatomical structures. MRAC was able to distinguish the knees and the body contour. Image fusion of PET and MR was able to localize the infection, which was confirmed by a physician. Pre-clinical imaging with the Ingenuity TF was deemed feasible, although PET imaging is limited by the resolution of the scanner. The preliminary sequences were successfully implemented for future studies on the Ingenuity TF.

Progress on dedicated animal PET

International Nuclear Information System (INIS)

Liu Wei

2002-01-01

Positron emission tomography, as the leading technology providing molecular imaging of biological processes, is widely used on living laboratory animals. High-resolution dedicated animal PET scanners have been developed. Although the dedicated animal PET faces obstacles and challenges, this advanced technology would play an important role in molecular biomedicine researches, such as diseases study, medicine development, and gene therapy

Impact of [F-18]-fluoro-ethyl-tyrosine PET imaging on target definition for radiation therapy of high-grade glioma

DEFF Research Database (Denmark)

af Rosenschold, Per Munck; Costa, Junia; Engelholm, Svend Aage

2015-01-01

BACKGROUND: We sought to assess the impact of amino-acid (18)F-fluoro-ethyl-tyrosine (FET) positron emission tomography (PET) on the volumetric target definition for radiation therapy of high-grade glioma versus the current standard using MRI alone. Specifically, we investigated the influence....... Patients with grade IV glioma were found to be the primary candidates for PET-guided radiation therapy planning....

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 a clinical whole-body system using simultaneous 1 H-MRI and PET but never for 13C-MRSI and PET. Here, the feasibility of simultaneous PET and 13C-MRSI as well as hyperpolarized 13C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Methods: Combined PET 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...

Positron Emission Tomography (PET)

International Nuclear Information System (INIS)

Welch, M.J.

1990-01-01

Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs

Positron Emission Tomography (PET)

Science.gov (United States)

Welch, M. J.

1990-01-01

Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

Positron Emission Tomography (PET)

Energy Technology Data Exchange (ETDEWEB)

Welch, M.J.

1990-01-01

Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs.

Benzodiazepine receptor distribution and cerebral blood flow in early blindness. A PET study

International Nuclear Information System (INIS)

Mishina, Masahiro; Senda, Michio; Kiyosawa, Motohiro

2000-01-01

We studied benzodiazepine receptor (BZR) distribution, which is thought to be affected by neuronal density in the cerebral cortex, and CBF using [ 11 C]flumazenil and [ 15 O]water PET in early blind (EB) and in blindfold sighted control (SC) subjects. PET images were co-registered to the subject's MRI. Using SPM96, MRI images were normalized in the Talairach and Tournoux coordinate system, and accordingly MRI-registered PET images were spatially normalized. Statistical parametric maps were computed on a voxel-by-voxel basis, using the general linear model. CBF for EB was significantly larger in the Brodmann area 17 and 18, especially anterior area, than that for SC, while there was no significant difference in BZR distribution. Our BZR data suggest that the amount of neurons do not change due to early visual deprivation in the visual cortex, in spite of high CBF in visual cortex of EB subjects. (author)

PET in management of breast cancer

International Nuclear Information System (INIS)

Lee, Myung-Chul

2004-01-01

Full text: PET provides useful information about tumor metabolism enabling accurate visualization of malignant lesions. Approximately 60-80% suspicious lesions on mammography have benign histology and about 10% of breast cancers with palpable mass are not identified in mammography. The key roles of PET technology in breast cancer are in: primary diagnosis, staging, recurrent diseases monitoring and prediction of therapy response. The sensitivity and specificity of FDG-PET for the diagnosis of breast cancer has been reported to be 68-100% and 83-100%, respectively. Considering the increasing number of small breast tumors detected by mammography and false negative results, the clinical relevance of FDG-PET for the primary diagnosis is limited. In selected patients, however, for example with dense breasts, breasts implants, augmented breast or after breast surgery, which can affect the accuracy of mammography, and in cases with equivocal mammography, FDG-PET can provide clinically relevant information. PET accurately determines the extent of disease, including the loco-regional lymph node status. Furthermore, whole-body PET imaging promises a high diagnostic accuracy for detecting recurrent or metastatic breast carcinoma with a high positive predictive value. We studied the usefulness of the FDG-PET in 42 preoperative patients with suspected breast cancer in differentiation of lesions. The diagnostic value of FDG-PET in terms of sensitivity and specificity was 95% and 77% respectively in primary mass while it was 73% and 100% for axillary lymph nodes. PET is much more accurate than other conventional modalities. The sensitivity of FDG-PET for correct staging of axillary nodal status is 84-100%. It has the potential to replace conventional procedures for the staging of distant metastases. We observed the sensitivity and the specificity of FDG-PET to be 96% and 85% to detect distant metastases. FDG-PET may become the method of choice for the early assessment of

Comparison of volumetric and functional parameters in simultaneous cardiac PET/MR: feasibility of volumetric assessment with residual activity from prior PET/CT

Energy Technology Data Exchange (ETDEWEB)

Luecke, C.; Brenneis, B.; Grothoff, M.; Gutberlet, M. [University Leipzig - Heart Center, Department of Diagnostic and Interventional Radiology, Leipzig (Germany); Oppolzer, B.; Werner, P.; Jochimsen, T.; Sattler, B.; Barthel, H.; Sabri, O. [University Hospital Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Foldyna, B. [University Leipzig - Heart Center, Department of Diagnostic and Interventional Radiology, Leipzig (Germany); Massachusetts General Hospital - Harvard Medical School, Cardiac MR PET CT Program, Boston, MA (United States); Lurz, P. [University Leipzig - Heart Center, Clinic for Internal Medicine/Cardiology, Leipzig (Germany); Lehmkuhl, L. [Herz- und Gefaess-Klinik GmbH, Radiologische Klinik, Bad Neustadt (Germany)

2017-12-15

To compare cardiac left ventricular (LV) parameters in simultaneously acquired hybrid fluorine-18-fluorodeoxyglucose ([18F] FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with residual tracer activity of upstream PET/CT. Twenty-nine patients (23 men, age 58±17 years) underwent cardiac PET/MRI either directly after a non-cardiac PET/CT with homogenous cardiac [18F] FDG uptake (n=20) or for viability assessment (n=9). Gated cardiac [18F] FDG PET and cine MR sequences were acquired simultaneously and evaluated blinded to the cross-imaging results. Image quality (IQ), end-diastolic (LVEDV), end-systolic volume (LVESV), ejection fraction (LVEF) and myocardial mass (LVMM) were measured. Pearson correlation and intraclass correlation coefficient (ICC), regression and a Bland-Altman analysis were assessed. Except LVMM, volumetric and functional LV parameters demonstrated high correlations (LVESV: r=0.97, LVEDV: r=0.95, LVEF: r=0.91, LVMM: r=0.87, each p<0.05), but wide limits of agreement (LOA) for LVEDV (-25.3-82.5ml); LVESV (-33.1-72.7ml); LVEF (-18.9-14.8%) and LVMM (-78.2-43.2g). Intra- and interobserver reliability were very high (ICC≥0.95) for all parameters, except for MR-LVEF (ICC=0.87). PET-IQ (0-3) was high (mean: 2.2±0.9) with significant influence on LVMM calculations only. In simultaneously acquired cardiac PET/MRI data, LVEDV, LVESV and LVEF show good agreement. However, the agreement seems to be limited if cardiac PET/MRI follows PET/CT and only the residual activity is used. (orig.)

Oral cancer diagnosed using PET/CT: A case report

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Hee; Yang, Byoung Eun; Cho, Young Min [Hallym Univ. College of Medicine, Anyang (Korea, Republic of); Kim, Seong Gon [Sam Anyang General Hospital, Anyang (Korea, Republic of)

2006-06-15

PET/CT is a new imaging technology that combines high-quality Position Emission Tomography (PET) and Computed Tomography (CT). This imaging provides simultaneous anatomical and metabolic information. Therefore PET/CT is useful diagnostic modality for early detection og malignant tumor, accurate at aging, decision on therapeutic plan, monitoring response to therapy and rapid detection of recurrence. We report oral and maxillofacial cancers diagnosed by using PET/CT and the usefulness of PET/CT in the evaluation of postoperative recurrence.

Nutritional Sustainability of Pet Foods12

Science.gov (United States)

Swanson, Kelly S.; Carter, Rebecca A.; Yount, Tracy P.; Aretz, Jan; Buff, Preston R.

2013-01-01

Sustainable practices meet the needs of the present without compromising the ability of future generations to meet their needs. Applying these concepts to food and feed production, nutritional sustainability is the ability of a food system to provide sufficient energy and essential nutrients required to maintain good health in a population without compromising the ability of future generations to meet their nutritional needs. Ecological, social, and economic aspects must be balanced to support the sustainability of the overall food system. The nutritional sustainability of a food system can be influenced by several factors, including the ingredient selection, nutrient composition, digestibility, and consumption rates of a diet. Carbon and water footprints vary greatly among plant- and animal-based ingredients, production strategy, and geographical location. Because the pet food industry is based largely on by-products and is tightly interlinked with livestock production and the human food system, however, it is quite unique with regard to sustainability. Often based on consumer demand rather than nutritional requirements, many commercial pet foods are formulated to provide nutrients in excess of current minimum recommendations, use ingredients that compete directly with the human food system, or are overconsumed by pets, resulting in food wastage and obesity. Pet food professionals have the opportunity to address these challenges and influence the sustainability of pet ownership through product design, manufacturing processes, public education, and policy change. A coordinated effort across the industry that includes ingredient buyers, formulators, and nutritionists may result in a more sustainable pet food system. PMID:23493530

PET and PET/CT in tumour of undetermined origin; PET y PET/CT en tumor de origen indeterminado

Energy Technology Data Exchange (ETDEWEB)

Garcia O, J R [Nuclear Medicine and Molecular Imaging, PET/CT, Centro Medico ABC, Mexico D.F. (Mexico)

2007-07-01

In this presentation the following conclusions were obtained regarding the use of PET and PET/CT in patient with cancer of unknown primary: 1. Detection of the primary one in 1/3 at 1/2 of patient. 2. It detects metastases in other places in 50%. 3. It changes the initial therapy planned in 1/3 at 1/2 of patient. 4. Useful in initial phases of protocol study to limit the other procedures. After standard evaluation. Before advanced protocol. 5. PET/CT study increases the % of primary detection, although in a non significant way vs. PET. 6. They are required more studies to value their utility to a more objective manner. (Author)

Feasibility of a novel design of high resolution parallax-free Compton enhanced PET scanner dedicated to brain research

CERN Document Server

Braem, André; Chesi, Enrico Guido; Correia, J G; Garibaldi, F; Joram, C; Mathot, S; Nappi, E; Ribeiro da Silva, M; Schoenahl, F; Séguinot, Jacques; Weilhammer, P; Zaidi, H

2004-01-01

A novel concept for a positron emission tomography (PET) camera module is proposed, which provides full 3D reconstruction with high resolution over the total detector volume, free of parallax errors. The key components are a matrix of long scintillator crystals and hybrid photon detectors (HPDs) with matched segmentation and integrated readout electronics. The HPDs read out the two ends of the scintillator package. Both excellent spatial (x, y, z) and energy resolution are obtained. The concept allows enhancing the detection efficiency by reconstructing a significant fraction of events which underwent Compton scattering in the crystals. The proof of concept will first be demonstrated with yttrium orthoaluminate perovskite (YAP):Ce crystals, but the final design will rely on other scintillators more adequate for PET applications (e.g. LSO:Ce or LaBr /sub 3/:Ce). A promising application of the proposed camera module, which is currently under development, is a high resolution 3D brain PET camera with an axial fi...

Assessment of various strategies for 18F-FET PET-guided delineation of target volumes in high-grade glioma patients

International Nuclear Information System (INIS)

Vees, Hansjoerg; Senthamizhchelvan, Srinivasan; Ratib, Osman; Miralbell, Raymond; Weber, Damien C.; Zaidi, Habib

2009-01-01

The purpose of the study is to assess the contribution of 18 F-fluoro-ethyl-tyrosine ( 18 F-FET) positron emission tomography (PET) in the delineation of gross tumor volume (GTV) in patients with high-grade gliomas compared with magnetic resonance imaging (MRI) alone. The study population consisted of 18 patients with high-grade gliomas. Seven image segmentation techniques were used to delineate 18 F-FET PET GTVs, and the results were compared to the manual MRI-derived GTV (GTV MRI ). PET image segmentation techniques included manual delineation of contours (GTV man ), a 2.5 standardized uptake value (SUV) cutoff (GTV 2.5 ), a fixed threshold of 40% and 50% of the maximum signal intensity (GTV 40% and GTV 50% ), signal-to-background ratio (SBR)-based adaptive thresholding (GTV SBR ), gradient find (GTV GF ), and region growing (GTV RG ). Overlap analysis was also conducted to assess geographic mismatch between the GTVs delineated using the different techniques. Contours defined using GTV 2.5 failed to provide successful delineation technically in three patients (18% of cases) as SUV max MRI (67% of cases). Yet, PET detected frequently tumors that are not visible on MRI and added substantially tumor extension outside the GTV MRI in six patients (33% of cases). The selection of the most appropriate 18 F-FET PET-based segmentation algorithm is crucial, since it impacts both the volume and shape of the resulting GTV. The 2.5 SUV isocontour and GF segmentation techniques performed poorly and should not be used for GTV delineation. With adequate setting, the SBR-based PET technique may add considerably to conventional MRI-guided GTV delineation. (orig.)

Comparison of {sup 18}F-FET PET and perfusion-weighted MRI for glioma grading. A hybrid PET/MR study

Energy Technology Data Exchange (ETDEWEB)

Verger, Antoine [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); Lorraine University, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Nancy (France); Lorraine University, IADI, INSERM, UMR 947, Nancy (France); Filss, Christian P. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Lohmann, Philipp; Stoffels, Gabriele; Rota Kops, Elena [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); Sabel, Michael [University of Duesseldorf, Department of Neurosurgery, Duesseldorf (Germany); Wittsack, Hans J. [University Duesseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Galldiks, Norbert; Fink, Gereon R. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); University of Cologne, Department of Neurology, Cologne (Germany); University of Cologne and Bonn, Center of Integrated Oncology (CIO), Bonn (Germany); Shah, Nadim J. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Neurology, Aachen (Germany); Juelich-Aachen Research Alliance (JARA), Section JARA-Brain, Juelich (Germany); Langen, Karl-Josef [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Juelich-Aachen Research Alliance (JARA), Section JARA-Brain, Juelich (Germany)

2017-12-15

Both perfusion-weighted MR imaging (PWI) and O-(2-{sup 18}F-fluoroethyl)-L-tyrosine PET ({sup 18}F-FET) provide grading information in cerebral gliomas. The aim of this study was to compare the diagnostic value of {sup 18}F-FET PET and PWI for tumor grading in a series of patients with newly diagnosed, untreated gliomas using an integrated PET/MR scanner. Seventy-two patients with untreated gliomas [22 low-grade gliomas (LGG), and 50 high-grade gliomas (HGG)] were investigated with {sup 18}F-FET PET and PWI using a hybrid PET/MR scanner. After visual inspection of PET and PWI maps (rCBV, rCBF, MTT), volumes of interest (VOIs) with a diameter of 16 mm were centered upon the maximum of abnormality in the tumor area in each modality and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios (TBR{sub mean}, TBR{sub max}) were calculated. In addition, Time-to-Peak (TTP) and slopes of time-activity curves were calculated for {sup 18}F-FET PET. Diagnostic accuracies of {sup 18}F-FET PET and PWI for differentiating low-grade glioma (LGG) from high-grade glioma (HGG) were evaluated by receiver operating characteristic analyses (area under the curve; AUC). The diagnostic accuracy of {sup 18}F-FET PET and PWI to discriminate LGG from HGG was similar with highest AUC values for TBR{sub mean} and TBR{sub max} of {sup 18}F-FET PET uptake (0.80, 0.83) and for TBR{sub mean} and TBR{sub max} of rCBV (0.80, 0.81). In case of increased signal in the tumor area with both methods (n = 32), local hot-spots were incongruent in 25 patients (78%) with a mean distance of 10.6 ± 9.5 mm. Dynamic FET PET and combination of different parameters did not further improve diagnostic accuracy. Both {sup 18}F-FET PET and PWI discriminate LGG from HGG with similar diagnostic performance. Regional abnormalities in the tumor area are usually not congruent indicating that tumor grading by {sup 18}F-FET PET and PWI is based on different pathophysiological phenomena. (orig.)

Towards enhanced PET quantification in clinical oncology

DEFF Research Database (Denmark)

Zaidi, Habib; Karakatsanis, Nicolas

2018-01-01

is still a matter of debate. Quantitative PET has advanced elegantly during the last two decades and is now reaching the maturity required for clinical exploitation, particularly in oncology where it has the capability to open many avenues for clinical diagnosis, assessment of response to treatment...... and therapy planning. Therefore, the preservation and further enhancement of the quantitative features of PET imaging is crucial to ensure that the full clinical value of PET imaging modality is utilized in clinical oncology. Recent advancements in PET technology and methodology have paved the way for faster...... PET acquisitions of enhanced sensitivity to support the clinical translation of highly quantitative 4D parametric imaging methods in clinical oncology. In this report, we provide an overview of recent advances and future trends in quantitative PET imaging in the context of clinical oncology. The pros...

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

Science.gov (United States)

Hansen, Adam E; Andersen, Flemming L; Henriksen, Sarah T; Vignaud, Alexandre; Ardenkjaer-Larsen, Jan H; Højgaard, Liselotte; Kjaer, Andreas; Klausen, Thomas L

2016-12-01

Integrated PET/MRI with hyperpolarized (13)C magnetic resonance spectroscopic imaging ((13)C-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 a clinical whole-body system using simultaneous (1)H-MRI and PET but never for (13)C-MRSI and PET. Here, the feasibility of simultaneous PET and (13)C-MRSI as well as hyperpolarized (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Combined PET and (13)C-MRSI phantoms including a NEMA [(18)F]-FDG phantom, (13)C-acetate and (13)C-urea sources, and hyperpolarized (13)C-pyruvate were imaged repeatedly with PET and/or (13)C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET trues; and (13)C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. PET and (13)C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in PET activity between acquisitions with and without simultaneous (13)C-MRSI was 0.83 (largest sphere) and -0.76 % (background). The average difference in net trues was -0.01 %. The average difference in (13)C-MRSI SNR between acquisitions with and without simultaneous PET ranged from -2.28 to 1.21 % for all phantoms and measurement conditions. No differences were significant. The system was capable of (13)C-MRSI of hyperpolarized (13)C-pyruvate. Simultaneous PET and (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is feasible. Phantom experiments showed that possible interference effects introduced by acquiring data from the two modalities simultaneously are small and non-significant. Further experiments can now investigate the benefits of simultaneous PET and

MR-based attenuation correction for cardiac FDG PET on a hybrid PET/MRI scanner: comparison with standard CT attenuation correction

Energy Technology Data Exchange (ETDEWEB)

Vontobel, Jan; Liga, Riccardo; Possner, Mathias; Clerc, Olivier F.; Mikulicic, Fran; Veit-Haibach, Patrick; Voert, Edwin E.G.W. ter; Fuchs, Tobias A.; Stehli, Julia; Pazhenkottil, Aju P.; Benz, Dominik C.; Graeni, Christoph; Gaemperli, Oliver; Herzog, Bernhard; Buechel, Ronny R.; Kaufmann, Philipp A. [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland)

2015-09-15

The aim of this study was to evaluate the feasibility of attenuation correction (AC) for cardiac {sup 18}F-labelled fluorodeoxyglucose (FDG) positron emission tomography (PET) using MR-based attenuation maps. We included 23 patients with no known cardiac history undergoing whole-body FDG PET/CT imaging for oncological indications on a PET/CT scanner using time-of-flight (TOF) and subsequent whole-body PET/MR imaging on an investigational hybrid PET/MRI scanner. Data sets from PET/MRI (with and without TOF) were reconstructed using MR AC and semi-quantitative segmental (20-segment model) myocardial tracer uptake (per cent of maximum) and compared to PET/CT which was reconstructed using CT AC and served as standard of reference. Excellent correlations were found for regional uptake values between PET/CT and PET/MRI with TOF (n = 460 segments in 23 patients; r = 0.913; p < 0.0001) with narrow Bland-Altman limits of agreement (-8.5 to +12.6 %). Correlation coefficients were slightly lower between PET/CT and PET/MRI without TOF (n = 460 segments in 23 patients; r = 0.851; p < 0.0001) with broader Bland-Altman limits of agreement (-12.5 to +15.0 %). PET/MRI with and without TOF showed minimal underestimation of tracer uptake (-2.08 and -1.29 %, respectively), compared to PET/CT. Relative myocardial FDG uptake obtained from MR-based attenuation corrected FDG PET is highly comparable to standard CT-based attenuation corrected FDG PET, suggesting interchangeability of both AC techniques. (orig.)

Bayesian reconstruction of photon interaction sequences for high-resolution PET detectors

Energy Technology Data Exchange (ETDEWEB)

Pratx, Guillem; Levin, Craig S [Molecular Imaging Program at Stanford, Department of Radiology, Stanford, CA (United States)], E-mail: cslevin@stanford.edu

2009-09-07

Realizing the full potential of high-resolution positron emission tomography (PET) systems involves accurately positioning events in which the annihilation photon deposits all its energy across multiple detector elements. Reconstructing the complete sequence of interactions of each photon provides a reliable way to select the earliest interaction because it ensures that all the interactions are consistent with one another. Bayesian estimation forms a natural framework to maximize the consistency of the sequence with the measurements while taking into account the physics of {gamma}-ray transport. An inherently statistical method, it accounts for the uncertainty in the measured energy and position of each interaction. An algorithm based on maximum a posteriori (MAP) was evaluated for computer simulations. For a high-resolution PET system based on cadmium zinc telluride detectors, 93.8% of the recorded coincidences involved at least one photon multiple-interactions event (PMIE). The MAP estimate of the first interaction was accurate for 85.2% of the single photons. This represents a two-fold reduction in the number of mispositioned events compared to minimum pair distance, a simpler yet efficient positioning method. The point-spread function of the system presented lower tails and higher peak value when MAP was used. This translated into improved image quality, which we quantified by studying contrast and spatial resolution gains.

Estudo do efeito do envelhecimento sob radiação UV no transporte de água em filmes de PET reciclados de bebidas carbonatadas Study of the UV ageing effect on water transport through PET films recycled from beverage bottles

Directory of Open Access Journals (Sweden)

Raquel B. Vichessi

2008-01-01

Full Text Available Este trabalho descreve um estudo sobre o efeito do envelhecimento sob radiação UV no transporte de água em filmes planos de PET reciclados de garrafas de bebidas carbonatadas. A partir do formalismo termodinâmico utilizando a relação de Eyring e os resultados de coeficientes de permeabilidade, foram determinadas a entropia e a entalpia de ativação para o transporte da água. Estas funções representadas num gráfico de efeito de compensação termodinâmica permitiram correlacionar a degradação do material, avaliada via espectroscopia na região do infravermelho com transformada de Fourier, com o transporte de água. Foram analisados os possíveis efeitos da presença de estabilizantes, pigmentos e história de processamento.This work describes a study about the UV ageing effect on water transport through PET film sheets recycled from beverage bottles. Using a thermodynamic formalism based on the Eyring relationship and results of water permeability coefficient, it is possible to determine the entropy and enthalpy of activation for the water transport process. These functions were correlated using the compensation thermodynamic plot and correlations were made between the degradation of the PET samples, measured by FTIR, and transport properties. Also, possible effects from the presence of stabilizers, pigments and processing history were analyzed.

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-08-21

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

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.

Motion compensation for fully 4D PET reconstruction using PET superset data

Energy Technology Data Exchange (ETDEWEB)

Verhaeghe, J; Gravel, P; Mio, R; Fukasawa, R; Rosa-Neto, P; Soucy, J-P; Thompson, C J; Reader, A J, E-mail: jeroen.verhaeghe@mcgill.c [Montreal Neurological Institute, McGill University, Montreal (Canada)

2010-07-21

Fully 4D PET image reconstruction is receiving increasing research interest due to its ability to significantly reduce spatiotemporal noise in dynamic PET imaging. However, thus far in the literature, the important issue of correcting for subject head motion has not been considered. Specifically, as a direct consequence of using temporally extensive basis functions, a single instance of movement propagates to impair the reconstruction of multiple time frames, even if no further movement occurs in those frames. Existing 3D motion compensation strategies have not yet been adapted to 4D reconstruction, and as such the benefits of 4D algorithms have not yet been reaped in a clinical setting where head movement undoubtedly occurs. This work addresses this need, developing a motion compensation method suitable for fully 4D reconstruction methods which exploits an optical tracking system to measure the head motion along with PET superset data to store the motion compensated data. List-mode events are histogrammed as PET superset data according to the measured motion, and a specially devised normalization scheme for motion compensated reconstruction from the superset data is required. This work proceeds to propose the corresponding time-dependent normalization modifications which are required for a major class of fully 4D image reconstruction algorithms (those which use linear combinations of temporal basis functions). Using realistically simulated as well as real high-resolution PET data from the HRRT, we demonstrate both the detrimental impact of subject head motion in fully 4D PET reconstruction and the efficacy of our proposed modifications to 4D algorithms. Benefits are shown both for the individual PET image frames as well as for parametric images of tracer uptake and volume of distribution for {sup 18}F-FDG obtained from Patlak analysis.

Pet Allergy Quiz

Science.gov (United States)

... Treatments ▸ Allergies ▸ Pet Allergy ▸ Pet Allergy Quiz Share | Pet Allergy Quiz More than half of U.S. households ... cat family. Yet, millions of people suffer from pet allergies. Take this quiz to test your knowledge ...

Colorectal cancer staging: comparison of whole-body PET/CT and PET/MR.

Science.gov (United States)

Catalano, Onofrio A; Coutinho, Artur M; Sahani, Dushyant V; Vangel, Mark G; Gee, Michael S; Hahn, Peter F; Witzel, Thomas; Soricelli, Andrea; Salvatore, Marco; Catana, Ciprian; Mahmood, Umar; Rosen, Bruce R; Gervais, Debra

2017-04-01

Correct staging is imperative for colorectal cancer (CRC) since it influences both prognosis and management. Several imaging methods are used for this purpose, with variable performance. Positron emission tomography-magnetic resonance (PET/MR) is an innovative imaging technique recently employed for clinical application. The present study was undertaken to compare the staging accuracy of whole-body positron emission tomography-computed tomography (PET/CT) with whole-body PET/MR in patients with both newly diagnosed and treated colorectal cancer. Twenty-six patients, who underwent same day whole-body (WB) PET/CT and WB-PET/MR, were evaluated. PET/CT and PET/MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Correct staging was compared between methods using McNemar's Chi square test. The two methods were in agreement and correct for 18/26 (69%) patients, and in agreement and incorrect for one patient (3.8%). PET/MR and PET/CT stages for the remaining 7/26 patients (27%) were discordant, with PET/MR staging being correct in all seven cases. PET/MR significantly outperformed PET/CT overall for accurate staging (P = 0.02). PET/MR outperformed PET/CT in CRC staging. PET/MR might allow accurate local and distant staging of CRC patients during both at the time of diagnosis and during follow-up.

A small animal PET based on GAPDs and charge signal transmission approach for hybrid PET-MR imaging

Energy Technology Data Exchange (ETDEWEB)

Kang, Jihoon; Choi, Yong; Hong, Key Jo; Hu, Wei; Jung, Jin Ho; Huh, Yoonsuk [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kim, Byung-Tae, E-mail: ychoi.image@gmail.com [Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of)

2011-08-15

Positron emission tomography (PET) employing Geiger-mode avalanche photodiodes (GAPDs) and charge signal transmission approach was developed for small animal imaging. Animal PET contained 16 LYSO and GAPD detector modules that were arranged in a 70 mm diameter ring with an axial field of view of 13 mm. The GAPDs charge output signals were transmitted to a preamplifier located remotely using 300 cm flexible flat cables. The position decoder circuits (PDCs) were used to multiplex the PET signals from 256 to 4 channels. The outputs of the PDCs were digitized and further-processed in the data acquisition unit. The cross-compatibilities of the PET detectors and MRI were assessed outside and inside the MRI. Experimental studies of the developed full ring PET were performed to examine the spatial resolution and sensitivity. Phantom and mouse images were acquired to examine the imaging performance. The mean energy and time resolution of the PET detector were 17.6% and 1.5 ns, respectively. No obvious degradation on PET and MRI was observed during simultaneous PET-MRI data acquisition. The measured spatial resolution and sensitivity at the CFOV were 2.8 mm and 0.7%, respectively. In addition, a 3 mm diameter line source was clearly resolved in the hot-sphere phantom images. The reconstructed transaxial PET images of the mouse brain and tumor displaying the glucose metabolism patterns were imaged well. These results demonstrate GAPD and the charge signal transmission approach can allow the development of high performance small animal PET with improved MR compatibility.

Cerebral blood flow with [15O]water PET studies using an image-derived input function and MR-defined carotid centerlines

Science.gov (United States)

Fung, Edward K.; Carson, Richard E.

2013-03-01

Full quantitative analysis of brain PET data requires knowledge of the arterial input function into the brain. Such data are normally acquired by arterial sampling with corrections for delay and dispersion to account for the distant sampling site. Several attempts have been made to extract an image-derived input function (IDIF) directly from the internal carotid arteries that supply the brain and are often visible in brain PET images. We have devised a method of delineating the internal carotids in co-registered magnetic resonance (MR) images using the level-set method and applying the segmentations to PET images using a novel centerline approach. Centerlines of the segmented carotids were modeled as cubic splines and re-registered in PET images summed over the early portion of the scan. Using information from the anatomical center of the vessel should minimize partial volume and spillover effects. Centerline time-activity curves were taken as the mean of the values for points along the centerline interpolated from neighboring voxels. A scale factor correction was derived from calculation of cerebral blood flow (CBF) using gold standard arterial blood measurements. We have applied the method to human subject data from multiple injections of [15O]water on the HRRT. The method was assessed by calculating the area under the curve (AUC) of the IDIF and the CBF, and comparing these to values computed using the gold standard arterial input curve. The average ratio of IDIF to arterial AUC (apparent recovery coefficient: aRC) across 9 subjects with multiple (n = 69) injections was 0.49 ± 0.09 at 0-30 s post tracer arrival, 0.45 ± 0.09 at 30-60 s, and 0.46 ± 0.09 at 60-90 s. Gray and white matter CBF values were 61.4 ± 11.0 and 15.6 ± 3.0 mL/min/100 g tissue using sampled blood data. Using IDIF centerlines scaled by the average aRC over each subjects’ injections, gray and white matter CBF values were 61.3 ± 13.5 and 15.5 ± 3.4 mL/min/100 g tissue. Using global

TOF-PET/MR和TOF-PET/CT在体部恶性肿瘤SUVmax值的比较%Comparision of SUVmax of TOF-PET/MR and TOF-PET/CT in body malignant tumor

Institute of Scientific and Technical Information of China (English)

宋天彬; 卢洁; 崔碧霄; 马杰; 杨宏伟; 马蕾; 梁志刚

2017-01-01

目的 探讨时间飞行(TOF)技术PET/CT和PET/MR检查体部恶性病变SUVmax值的一致性.方法 回顾性分析接受TOF-PET/CT和TOF-PET/MR检查的体部恶性肿瘤患者20例,分为先PET/CT后PET/MR组和先PET/MR后PET/CT组,每组10例.采用Bland-Altma图评价两次检查病灶SUVmax值的一致性,采用多因素方差分析评价扫描顺序和机器类型对病灶的SUVmax测量值的影响.结果 TOF-PET/CT与TOF-PET/MR检查病灶的SUVmax值有较好的一致性[先PET/CT后PET/MR组:均值差为3.06,95％CI(-7.5,13.6),先PET/MR后PET/CT组:均值差3.0,95％CI(-2.4,8.3)].扫描顺序对于恶性病灶的SUVmax有影响(F=46.00,P＜0.001),而机器类型对恶性病灶的SUVmax值无影响(F=0.005,P=0.95).结论 TOF-PET/MR和TOF-PET/CT在体部恶性病变SUVmax值测量方面具有相当的诊断价值,且延迟显像SUVmax的增加与采集时间有关,而与检查机器类型无关.%Objective To explore the consistency of time-of-flight (TOF) technology of PET/MRI and PET/CT for max standardized uptake value (SUVmax) of body malignant tumors.Methods A retrospective analysis of TOF-PET/CT and TOF-PET/MR imaging data about twenty patients with body malignant tumors was performed.Patients were divided into two groups (each n=10),including PET/CT first and sequentially PET/MR group and PET/MR first and sequentially PET/CT group.Bland-Altman figure was used to evaluate consistency of SUVmax of malignant lesions between TOF-PET/CT and TOF-PET/MR.Multi-way ANOVA was used to analysis effect of machine type and exam order on SUVmaxof malignant lesions in TOF-PET/CT and TOF-PET/MR.Results SUVmax of malignant lesions in TOF-PET/CT and TOF-PET/MR had good consistency in two groups (PET/CT first and sequentially PET/MR group:Mean difference was 3.06,95％CI was [-7.5,13.6];PET/MR first and sequentially PET/CT group:Mean difference was 3.0,95％CI was [-2.4,8.3]).SUVmax was not influenced by machine type (F=0.005,P=0.95),but exam order (F=46.00,P＜0

Assessment of recycled PET properties for application on oil wells as sand control agents; Avaliacao de propriedades de PET reciclado para aplicacao em pocos de petroleo como agente de contencao de areia

Energy Technology Data Exchange (ETDEWEB)

Pereira, Alexandre Zacarias Ignacio [PETROBRAS, Rio de Janeiro, RJ (Brazil); Delpech, Marcia Cerqueira [Universidade do Estado do Rio de Janeiro (IQ/UERJ), RJ (Brazil). Inst. de Quimica], e-mail: mcd@uerj.br

2008-07-01

The Sand Control is fundamental for oil production in unconsolidated sandstone formations. It consists of the installation of a filter made of stainless steel screens and grained materials (sand control agents) which are, normally, high density inorganic substances (sand, ceramic, bauxite). Shallow formations, near to the sea bed, are more sensitive and need different kinds of sand control agents with low density. The objective of this work was the evaluation of recycled poly(ethylene terephthalate), PET, as sand control agent for oil wells. Pack permeability and thermal stability tests results, after up to six months of exposure to sea water and crude oil, have indicated that the recycled PET kept the necessary characteristics for the proposed application. Also, it was observed that the PET grain pack did not presented significant property modifications in the exposure conditions, when compared to the non-exposed samples. (author)

High diversity of Staphylococcus aureus and Staphylococcus pseudintermedius lineages and toxigenic traits in healthy pet-owning household members. Underestimating normal household contact?

Science.gov (United States)

Gómez-Sanz, Elena; Torres, Carmen; Lozano, Carmen; Zarazaga, Myriam

2013-01-01

Forty-three unrelated pet-owning households were screened in Spain to study the Staphylococcus aureus and Staphylococcus pseudintermedius nasal carriage, their genetic lineages and virulence traits. Sixty-seven healthy owners and 66 healthy pets were investigated. Isolates characterization was performed and potential interspecies transmission was assessed. S. aureus was present in 51.2% of households studied while S. pseudintermedius in 30.2%. Twenty-eight owners (41.8%) carried S. aureus: one methicillin-resistant S. aureus (MRSA) [t5173-ST8-SCCmecIVa] and 27 methicillin-susceptible S. aureus (MSSA). Three owners (4.5%) were colonized by methicillin-susceptible S. pseudintermedius (MSSP). Fifteen pets (22.7%) carried S. pseudintermedius: two methicillin-resistant S. pseudintermedius (MRSP) [ST71-SCCmecII/III; ST92-SCCmecV] and 13 MSSP; in addition, 8 pets (12.1%) presented MSSA. High diversity of spa and sequence types (STs) was detected. Typical livestock-associated S. aureus lineages (CC398, CC9) were observed in humans and/or companion animals and hospital and/or community-acquired S. aureus lineages (CC45, CC121, CC5, CC8) were detected among pets. Almost 40% of S. pseudintermedius were multidrug-resistant. S. aureus isolates harboured a remarkable high number of virulence genes. The expA gene was detected in 3 S. pseudintermedius isolates. Identical strains from both owners and their pets were identified in 5 households (11.6%): (a) four MSSA (t073-ST45/CC45, t159-ST121/CC121, t209-ST109/CC9, t021-ST1654([new])/singleton) and (b) one multidrug-resistant MSSP (ST142([new])). Highly clonally diverse and toxigenic S. aureus and S. pseudintermedius are common colonizers of healthy humans and pets. The presence of these bacterial species, virulence genes, and interspecies transmission detected, points out to consider pet ownership as a risk factor to acquire, maintain and spread, potential pathogenic bacteria. Copyright © 2012 Elsevier Ltd. All rights reserved.

Particle identification with Polyethylene Terephthalate (PET) detector with high detection threshold

Science.gov (United States)

Dey, S.; Maulik, A.; Raha, Sibaji; Saha, Swapan K.; Syam, D.

2014-10-01

In the present work we describe the results of studies, using accelerator data, to determine the accuracy with which particles can be identified and their energies determined with a commercially available polymer (PET) used as a Nuclear Track Detector (NTD). The achieved charge resolution was ± 1 . The initial energy of stopping particle in PET was determined with an accuracy of 10 % for ion energies above the Bragg peak.

Particle identification with Polyethylene Terephthalate (PET) detector with high detection threshold

Energy Technology Data Exchange (ETDEWEB)

Dey, S. [Centre for Astroparticle Physics and Space Science, Bose Institute, Kolkata 700 091 (India); Maulik, A., E-mail: atanu.maulik@gmail.com [Centre for Astroparticle Physics and Space Science, Bose Institute, Kolkata 700 091 (India); Raha, Sibaji; Saha, Swapan K. [Centre for Astroparticle Physics and Space Science, Bose Institute, Kolkata 700 091 (India); Department of Physics, Bose Institute, Kolkata 700 009 (India); Syam, D. [Department of Physics, Barasat Government College, Kolkata 700 124 (India)

2014-10-01

In the present work we describe the results of studies, using accelerator data, to determine the accuracy with which particles can be identified and their energies determined with a commercially available polymer (PET) used as a Nuclear Track Detector (NTD). The achieved charge resolution was ±1. The initial energy of stopping particle in PET was determined with an accuracy of 10% for ion energies above the Bragg peak.

Four-layer depth-of-interaction PET detector for high resolution PET using a multi-pixel S8550 avalanche photodiode

Energy Technology Data Exchange (ETDEWEB)

Nishikido, Fumihiko, E-mail: funis@nirs.go.j [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Inadama, Naoko [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Oda, Ichiro [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Shibuya, Kengo; Yoshida, Eiji; Yamaya, Taiga [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kitamura, Keishi [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Murayama, Hideo [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2010-09-21

Avalanche photodiodes (APDs) are being used as photodetectors in positron emission tomography (PET) because they have many advantages over photomultipliers (PMTs) typically used in PET detectors. We have developed a PET detector that consists of a multi-pixel APD and a 6x6x4 array of 1.46x1.46 mm{sup 2}x4.5 m LYSO crystals for a small animal PET scanner. The detector can identify four-layer depth of interaction (DOI) with a position-sensitive APD coupled to the backside of a crystal array by just an optimized reflector arrangement. Since scintillation lights are shared among many pixels by the method, weaker signals in APD pixels far from the interacting crystals are affected by noise. To evaluate the performance of the four-layer DOI detector with the APD and the influence of electrical noise on our method, we constructed a prototype DOI detector and tested its performance. We found, except for crystal elements on the edge of the crystal array, all crystal elements could be identified from the 2D position histogram. An energy resolution of 16.9% was obtained for the whole crystal array of the APD detector. The results of noise dependence of detector performances indicated that the DOI detector using the APD could achieve sufficient performance even when using application-specific integrated circuits.

Four-layer depth-of-interaction PET detector for high resolution PET using a multi-pixel S8550 avalanche photodiode

International Nuclear Information System (INIS)

Nishikido, Fumihiko; Inadama, Naoko; Oda, Ichiro; Shibuya, Kengo; Yoshida, Eiji; Yamaya, Taiga; Kitamura, Keishi; Murayama, Hideo

2010-01-01

Avalanche photodiodes (APDs) are being used as photodetectors in positron emission tomography (PET) because they have many advantages over photomultipliers (PMTs) typically used in PET detectors. We have developed a PET detector that consists of a multi-pixel APD and a 6x6x4 array of 1.46x1.46 mm 2 x4.5 m LYSO crystals for a small animal PET scanner. The detector can identify four-layer depth of interaction (DOI) with a position-sensitive APD coupled to the backside of a crystal array by just an optimized reflector arrangement. Since scintillation lights are shared among many pixels by the method, weaker signals in APD pixels far from the interacting crystals are affected by noise. To evaluate the performance of the four-layer DOI detector with the APD and the influence of electrical noise on our method, we constructed a prototype DOI detector and tested its performance. We found, except for crystal elements on the edge of the crystal array, all crystal elements could be identified from the 2D position histogram. An energy resolution of 16.9% was obtained for the whole crystal array of the APD detector. The results of noise dependence of detector performances indicated that the DOI detector using the APD could achieve sufficient performance even when using application-specific integrated circuits.

PET/CT in radiation therapy planning; PET/CT in der Strahlentherapieplanung

Energy Technology Data Exchange (ETDEWEB)

Grosu, A.L. [Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany); Krause, B.J. [Klinik fuer Nuklearmedizin, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany); Nestle, U. [Klinik fuer Nuklearmedizin, Universitaetsklinikum des Saarlandes, Homburg/Saar (Germany)

2006-09-15

Regarding treatment planning in radiotherapy PET offers advantages in terms of tumor delineation and the description of biological processes. To define the real impact of this investigation in radiation treatment planning, following experimental, clinical and cost/benefit analysis are required. FDG-PET has a significant impact on GTV and PTV delineation in lung cancer and can detect lymph node involvement and differentiation of malignant tissue from atelectasis. In high-grade gliomas and meningiomas, methionine-PET helps to define the GTV and differentiate tumor from normal tissue. In head and neck cancer, cervix cancer and prostate cancer the value of FDG-PET for radiation treatment planning is still under investigation. For example, FDG-PET can be superior to CT and MRI in the detection of lymph node metastases in head and neck, unknown primary cancer and differentiation of viable tumor tissue after treatment. Therefore, it could play an important role in GTV definition and sparing of normal tissue. For other entities like gastro-intestinal cancer, lymphomas, sarcoma etc., the data of the literature are yet insufficient. The imaging of hypoxia, cell proliferation, angiogenesis, apoptosis and gene expression leads to the identification of different areas of a biologically heterogeneous tumor mass that can be individually targeted using IMRT. In addition, a biological dose distribution can be generated, the so-called dose painting. However, systematical experimental and clinical trials are necessary to validate this hypothesis. (orig.)

Semi-Supervised Tripled Dictionary Learning for Standard-dose PET Image Prediction using Low-dose PET and Multimodal MRI

Science.gov (United States)

Wang, Yan; Ma, Guangkai; An, Le; Shi, Feng; Zhang, Pei; Lalush, David S.; Wu, Xi; Pu, Yifei; Zhou, Jiliu; Shen, Dinggang

2017-01-01

Objective To obtain high-quality positron emission tomography (PET) image with low-dose tracer injection, this study attempts to predict the standard-dose PET (S-PET) image from both its low-dose PET (L-PET) counterpart and corresponding magnetic resonance imaging (MRI). Methods It was achieved by patch-based sparse representation (SR), using the training samples with a complete set of MRI, L-PET and S-PET modalities for dictionary construction. However, the number of training samples with complete modalities is often limited. In practice, many samples generally have incomplete modalities (i.e., with one or two missing modalities) that thus cannot be used in the prediction process. In light of this, we develop a semi-supervised tripled dictionary learning (SSTDL) method for S-PET image prediction, which can utilize not only the samples with complete modalities (called complete samples) but also the samples with incomplete modalities (called incomplete samples), to take advantage of the large number of available training samples and thus further improve the prediction performance. Results Validation was done on a real human brain dataset consisting of 18 subjects, and the results show that our method is superior to the SR and other baseline methods. Conclusion This work proposed a new S-PET prediction method, which can significantly improve the PET image quality with low-dose injection. Significance The proposed method is favorable in clinical application since it can decrease the potential radiation risk for patients. PMID:27187939

Contribution of modulated DSc to study the thermal behaviour of PET films drawn in hot water

International Nuclear Information System (INIS)

Zumalian, Abubaker

2003-01-01

PET films uni-axially drawn in hot water are studied by means of conventional DSc and modulated DSc. The glass transition is studied by modulated DSc which allows access to the values of the glass transition temperature T g and the variations of δ C p = C p 1-C p g (difference between thermal capacity in the liquid-like and glassy states at T = T g ). Variations of T g with the water content (which act as plasticizer) and with the drawing (which rigidifies the amorphous phase) are discussed in regard to the structure engaged in these materials. The variations of δ C p are also interpreted with the help of a three phase model and a strong-fragile glass former liquid concept. We show that the fragility of the medium increases by the conjugated effects of deformation and water as soon as a strain induced crystalline phase is obtained, and it decreases drastically when the rigid amorphous phase occurs. (author)

Surface Treatment of PET Nonwovens with Atmospheric Plasma

International Nuclear Information System (INIS)

Li Shufang

2013-01-01

In this study, polyethylene-terephthalate (PET) nonwovens are treated using an atmospheric plasma and the effects of the treatment time, treatment power and discharge distance on the ability of water-penetration into the nonwovens are investigated. The result indicates that the method can improve the wettability of PET nonwovens remarkably, but the aging decay of the sample's wettability is found to be notable as a function of the storage time after treatment due to the internal rotation of the single bond of surface macromolecules. As shown by SEM and XPS analysis, the etching and surface reaction are significant, and water-penetration weight is found to increase remarkably with the increasing power. This variation can be attributed to momentum transfer and enhanced higher-energy particle excitation.

18F-DOPA PET/CT for assessment of response to induction chemotherapy in a child with high-risk neuroblastoma

International Nuclear Information System (INIS)

Piccardo, Arnoldo; Lopci, Egesta; Foppiani, Luca; Morana, Giovanni; Conte, Massimo

2014-01-01

Functional imaging plays a crucial role in the assessment of neuroblastoma. The evaluation of response to induction chemotherapy is a cornerstone in scheduling proper treatment management in patients affected by high-risk neuroblastoma. 123 I-metaiodobenzylguanidine has been recognized as the radiopharmaceutical of choice in neuroblastoma assessment. To date, the clinical role of PET/CT in pediatric malignancy is not well established. 18 F-DOPA-PET/CT has been recently used in neuroblastoma, and compared with 123 I-MIBG-scan. Scant new data are available about the role of this tool in the evaluation of treatment response after induction chemotherapy. We investigate the role of 18 F-DOPA-PET/CT in characterizing the response to induction chemotherapy in a child affected by high-risk-neuroblastoma, in whom the rare association of 123 I-MIBG-negative primary tumor and MIBG-positive bone marrow metastases was observed. (orig.)

Current opinion on PET for gastrointestinal tumors

International Nuclear Information System (INIS)

Diederichs, C.G.; Schirrmeister, H.; Staib, L.

2000-01-01

The benefit of FDG-PET for restaging of colorectal carcinoma and for the differentiation of indeterminate hepatic lesions is well-documented. Accuracies of FDG-PET for recurrence, lymph node status and the detection of distant metastases are higher compared with computed tomography, for example. For other epithelial gastrointestinal tumors similar results have also been demonstrated in smaller trials or case presentations. The differentiation of recurrent rectal carcinoma from scar and PET for endocrine tumors are described elsewhere (Der Nuklearmediziner PET II, in preparation). Almost no data exist for rare tumors like anal carcinoma or tumors of the small intestines. For hepatocellular carcinoma, FDG-PET has a high positive predictive value, and the intensity of the uptake correlates well with grading. However, FDG-PET is not suitable for the exclusion of hepatocellular carcinoma due to insufficient sensitivity. The differentiation of benign and malignant pancreatic masses works well for selected patients. FDG-PET for lymph node staging is at least as accurate as conventional staging, and for the detection of distant metastases FDG-PET is superior compared with conventional staging. Few data exist on therapy control of gastrointestinal tumors. (orig.) [de

Who wants cancer screening with PET?

International Nuclear Information System (INIS)

Yasunaga, Hideo

2009-01-01

Objectives: Cancer screening using whole-body fluorodeoxyglucose-positron emission tomography (FDG-PET) has gradually become popular in Japan. Although some studies have reported high cancer detection rates with PET screening, the justification for such an approach is still unclear, and no evidence has been provided to indicate that PET screening reduces cancer mortality. We measured the general public's willingness to pay (WTP) for this service using a contingent valuation method, after providing them with sufficient information regarding the efficacy and limitations of the service. Methods: A computer-assisted questionnaire survey was conducted on males and females in Japan aged between 40 and 59 years. The study participants (n = 390) were provided with sufficient information about the PET procedure, the high cancer detection rate, false-negatives/false-positives and the fact that the mortality-reducing effect of PET screening has not yet been demonstrated. The participants' WTP was ascertained by a double-bound dichotomous choice approach. Results: The average WTP among all the participants was $68.0 (95% confidence interval: $56.9-79.2). A Weibull regression analysis showed that income, degree of concern about health, and family history of cancer were significant factors affecting WTP. Conclusions: The actual charge for PET screening in Japan is approximately $1000 on average, which is significantly higher than the participants' WTP for the actual benefit obtained from the service. If the Japanese healthcare consumers are well-informed, most of them would avoid purchasing such a costly service.

Implementation and performance of an optical motion tracking system for high resolution brain PET imaging

Science.gov (United States)

Lopresti, B. J.; Russo, A.; Jones, W. F.; Fisher, T.; Crouch, D. G.; Altenburger, D. E.; Townsend, D. W.

1999-12-01

Head motion during PET scanning is widely regarded as a source of image degradation and resolution loss. Recent improvements in the spatial resolution of state-of-the-art tomographs may be compromised by patient motion during scanning, as these high resolution data will be increasingly susceptible to smaller movements of the head. The authors have developed an opto-electronic motion tracking system based on commercially-available technology that is capable of very accurate real-time measurements of the position and orientation of the patient's head. These positions are transformed to the reference frame of the PET scanner, and could potentially be used to provide motion correction of list-mode emission data on an event-by-event basis.

Diagnostic value of [18F] FDG-PET and PET/CT in urinary bladder cancer: a meta-analysis.

Science.gov (United States)

Zhang, Huojun; Xing, Wei; Kang, Qinqin; Chen, Chao; Wang, Linhui; Lu, Jianping

2015-05-01

An early diagnosis of urinary bladder cancer is crucial for early treatment and management. The objective of this systematic review was to assess the overall diagnostic accuracy of 18 F FDG-PET and PET/CT in urinary bladder cancer with meta-analysis. The PubMed and CNKI databases were searched for the eligible studies published up to June 01, 2014. The sensitivity, specificity, and other measures of accuracy of 18 F FDG-PET and PET/CT in the diagnosis of urinary bladder cancer were pooled along with 95 % confidence intervals (CI). Summary receiver operating characteristic (ROC) curves were used to summarize overall test performance. Ten studies met our inclusion criteria. The summary estimates for 18 F FDG-PET and PET/CT in the diagnosis of urinary bladder cancer in meta-analysis were as follows: a pooled sensitivity, 0.82 (95 % confidence interval [CI], 0.75 to 0.88); a pooled specificity, 0.92 (95 % CI, 0.87 to 0.95); positive likelihood ratio, 6.80 (95 % CI, 4.31 to 10.74); negative likelihood ratio, 0.27 (95 % CI, 0.19 to 0.36); and diagnostic odds ratio, 25.18 (95 % CI, 17.58 to 70.4). The results indicate that 18 F FDG-PET and PET/CT are relatively high sensitive and specific for the diagnosis of urinary bladder cancer.

Effect of Attenuation Correction on Regional Quantification Between PET/MR and PET/CT

DEFF Research Database (Denmark)

Teuho, Jarmo; Johansson, Jarkko; Linden, Jani

2016-01-01

UNLABELLED: A spatial bias in brain PET/MR exists compared with PET/CT, because of MR-based attenuation correction. We performed an evaluation among 4 institutions, 3 PET/MR systems, and 4 PET/CT systems using an anthropomorphic brain phantom, hypothesizing that the spatial bias would be minimized....../MR systems, CTAC was applied as the reference method for attenuation correction. RESULTS: With CTAC, visual and quantitative differences between PET/MR and PET/CT systems were minimized. Intersystem variation between institutions was +3.42% to -3.29% in all VOIs for PET/CT and +2.15% to -4.50% in all VOIs...... for PET/MR. PET/MR systems differed by +2.34% to -2.21%, +2.04% to -2.08%, and -1.77% to -5.37% when compared with a PET/CT system at each institution, and these differences were not significant (P ≥ 0.05). CONCLUSION: Visual and quantitative differences between PET/MR and PET/CT systems can be minimized...

Quantitative PET imaging with the 3T MR-BrainPET

International Nuclear Information System (INIS)

Weirich, C.; Scheins, J.; Lohmann, P.; Tellmann, L.; Byars, L.; Michel, C.; Rota Kops, E.; Brenner, D.; Herzog, H.; Shah, N.J.

2013-01-01

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

Brain PET scan

Science.gov (United States)

... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...

Thoracic staging in lung cancer: prospective comparison of 18F-FDG PET/MR imaging and 18F-FDG PET/CT.

Science.gov (United States)

Heusch, Philipp; Buchbender, Christian; Köhler, Jens; Nensa, Felix; Gauler, Thomas; Gomez, Benedikt; Reis, Henning; Stamatis, Georgios; Kühl, Hilmar; Hartung, Verena; Heusner, Till A

2014-03-01

/MR imaging exhibited a high correlation (R = 0.74 and 0.86, respectively; P dedicated pulmonary MR imaging protocol, compared with (18)F-FDG PET/CT, does not provide advantages in thoracic staging in NSCLC patients.

FDG PET/CT in cancer

DEFF Research Database (Denmark)

Petersen, Henrik; Holdgaard, Paw Christian; Madsen, Poul Henning

2016-01-01

PURPOSE: The Region of Southern Denmark (RSD), covering 1.2 of Denmark's 5.6 million inhabitants, established a task force to (1) retrieve literature evidence for the clinical use of positron emission tomography (PET)/CT and provide consequent recommendations and further to (2) compare the actual...... use of PET/CT in the RSD with these recommendations. This article summarizes the results. METHODS: A Work Group appointed a professional Subgroup which made Clinician Groups conduct literature reviews on six selected cancers responsible for 5,768 (62.6 %) of 9,213 PET/CT scans in the RSD in 2012...... use of PET/CT and literature-based recommendations was high in the first five mentioned cancers in that 96.2 % of scans were made for grade A or B indications versus only 22.2 % in gynaecological cancers. CONCLUSION: Evidence-based usefulness was reported in five of six selected cancers; evidence...

Clinical PET application

Energy Technology Data Exchange (ETDEWEB)

Lim, Sang Moo; Hong, Song W.; Choi, Chang W.; Yang, Seong Dae [Korea Cancer Center Hospital, Seoul (Korea)

1997-12-01

PET gives various methabolic images, and is very important, new diagnostic modality in clinical oncology. In Korea Cancer Center Hospital, PET is installed as a research tool of long-mid-term atomic research project. For the efficient use of PET for clinical and research projects, income from the patients should be managed to get the raw material, equipment, manpower, and also for the clinical PET research. 1. Support the clinical application of PET in oncology. 2. Budgetary management of income, costs for raw material, equipment, manpower, and the clinical PET research project. In this year, 250 cases of PET images were obtained, which resulted total income of 180,000,000 won. 50,000,000 won was deposited for the 1998 PET clinical research. Second year PET clinical research should be managed under unified project. Increased demand for {sup 18}FDG in and outside KCCH need more than 2 times production of {sup 18}FDG in a day purchase of HPLC pump and {sup 68}Ga pin source which was delayed due to economic crisis, should be done early in 1998. (author). 2 figs., 3 tabs.