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Objective To test and analyze the performance of Biograph Vision 600 PET/CT according to the NEMA NU2—2012 standard to achieve reliable, repeatable, and inter-system comparable performance measurement, and to provide a basis for future equipment stability testing and status detection. Methods The Biograph Vision PET equipment features a detector based on silicon photomultipliers, with 3.2 mm lutetium oxyorthosilicate crystals and full cover of the scintillation region. The spatial resolution, sensitivity, noise-equivalent count rate, scatter fraction, coincidence count rate, image quality, scatter correction, and time-of-flight resolution of Biograph Vision PET were tested by referring to the test model and method of the NEMA NU2—2012 standard. Results The Biograph Vision 600 PET equipment showed lateral and axial spatial resolutions of 3.69 mm and 3.81 mm at 1 cm off-center of the field of view, respectively and of 4.29 mm and 4.48 mm at 10 cm, respectively. The sensitivity was 17.5 kcps/MBq. The time-of-flight resolution changed from 210 ps to 215 ps as the count rate increased to the peak noise equivalent count rate. The NEMA peak noise-equivalent count rate was 247 kcps at 30.3 kBq/ml. The corresponding scatter fraction was 34.8%. With the NEMA module, the overall image quality contrast range was 73.6%-92.8%, and the background variability was 2.3%-6.5%; the mean lung residual error was 3.4%; and the time-of-flight resolution was 210 ps. Conclusion This performance test was performed according to the NEMA NU2—2012 standard, showing that all parameters were better than the ex-factory standard, which can provide a reference for other institutions selecting equipment and also provide a basis for future equipment stability testing and status detection.
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Objective: To provide reference for the performance testing of single photon emission computed tomography (SPECT) based on CZT detector by correct applying NEMA NU1-2007 that established by NEMA. Methods: When the performance of SPECT based on CZT detector was tested, the CZT detector should be distinguished from single crystal detector. And the items of performance testing of CZT detector that was not suitable for NEMA NU1-2007 standard were discussed and explored. Result: The experiment items which was not suitable for NEMA NU1-2007 standard were grasped, and the research provided the relative analysis of reason and method of disposition. Conclusion: The performance testing of SPECT based on CZT detector could not completely be implemented according to the standard of NEMA NU1-2007. Besides, manufacturer need know which testing items were inapplicable and their reasons.
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Objective To analyze the influence factors on, and the relationship between, the system performance parameters by testing SPECT equipment.Methods By reference to National Electrical Manufactures Association standards and manufacturer's specifications, the performances of a total of 31 SPECTs in 12 provinces were measured, for the first time, with regard to their system spatial resolution (SSR) , system planar sensitivity (SPS) and tomographic spatial resolution (TPR).Results The results were as follows: (7.90 ± 0.62) mm for SSR, with the highest 9.46 mm and the lowest 7.04 mm;(78.54± 13.17)s-1· MBq-1 for SPS, with the highest 123.80 s-1 · MBq-1 and the lowest 56.70 s-1·MBq-1;and (13.12 ± 2.59) mm for TSR, with the highest 18.13 mm and the lowest 8.45 mm.These values indicated a nearly consistent upward and downward trend and could meet the clinical requirements by comparison with the manufactuer' s specifications.Conclusions Mutual restrictions have been shown between SSR and SPS.Increased thickness of the system crystal plane can improve the SPS, but also has a negative impact on the SSR.For all the above reasons, it is the optimum solution to choose the right type of collimator and crystal thickness for different clinical applications.
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La presente investigación tiene como objetivo el desarrollo de un servidor de almacenamiento y transmisión de imágenes médicas. Es un sistema orientado al área de radiología de una clínica hospitalaria, con el fin de almacenar y transmitir las imágenes generadas por los equipos de adquisición. Se ha elaborado según lo estipulado en el estándar DICOM 3.0 para el almacenamiento y transmisión de las imágenes médicas. Fue desarrollado sobre plataforma .NET con lenguaje de programación C#, utilizando el Framework 4.0, lo cual facilitará la migración hacia una plataforma libre. Posee una interfaz amigable que posibilita que la aplicación sea fácil de configurar. La implantación del sistema proporciona un mejor desempeño del sistema alas PACS y las imágenes médicas adquiridas son almacenadas de forma segura y quedando disponibles a los especialistas para su posterior uso(AU)
This research aims to develop a server for the storage and transmission of medical images. It is a system oriented toward the radiology needs of a real hospital, in order to store and transmit the images generated by the acquisition equipment. It has been prepared as required by the DICOM 3.0 standard for the storage and transmission of medical images. It was developed on .NET platform with C# programming language, using the Framework 4.0. It has a friendly interface that allows the application to be easy to configure. The implementation of the system provides a better performance for the alas PACS system and the medical images acquired are securely stored and are available to specialists for further use(AU)
Subject(s)
Humans , Male , Female , Image Processing, Computer-Assisted/methods , Medical Informatics Applications , Software DesignABSTRACT
Objective:To explore the SPECT detection method of quality control in detection of main performance index. Methods: according to the 2007 edition of SPECT performance measurementof the NEMA (the United States Electrical Manufacturers Association) standard, and the corresponding model of intrinsic spatial resolution, intrinsic spatial non-linearity, intrinsic non-uniformity, characteristic count rate, system planar sensitivity, system spatial resolution, fault spatial resolution and other indicators. Results: after quality control testing, have deviation more index hospitals SPECT results. Conclusion: the hospital should detect quality control as far as possible in nuclear medicine and nuclear medicine imaging equipment, ensure the normal operation of equipment, and improve the quality of image.
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Inveon PET is a recently developed preclinical PET system for small animal. This study was conducted to measure the performance of Inveon PET as recommended by the NEMA NU 4-2008. We measured the spatial resolution, the sensitivity, the scatter fraction and the NECR using a F-18 source. A 3.432 ns coincidence window was used. A 1 mm3 sized F-18 point source was used for the measurement of spatial resolution within an energy window of 350~625 keV. PET acquisition was performed to obtain the spatial resolution from the center to the 5 cm offset toward the edge of the transverse FOV. Sensitivity, scatter fraction, and NECR were measured within an energy window of 350~750 keV. For measuring the sensitivity, a F-18 line source (length: 12.7 cm) was used with concentric 5 aluminum tubes. For the acquisition of the scatter fraction and the NECR, two NEMA scatter phantoms (rat: 50 mm in diameter, 150 mm in length; mouse: 25 mm in diameter, 70 mm in length) were used and the data for 14 half-lives (25.6 hr) was obtained using the F-18 line source (rat: 316 MBq, mouse: 206 MBq). The spatial resolution of the F-18 point source was 1.53, 1.50 and 2.33 mm in the radial, tangential and axial directions, respectively. The volumetric resolution was 5.43 mm3 in the center. The absolute sensitivity was 6.61%. The peak NECR was 486 kcps @121 MBq (rat phantom), and 1056 kcps @128 MBq (mouse phantom). The values of the scatter fraction were 20.59% and 7.93% in the rat and mouse phantoms, respectively. The performances of the Inveon animal PET scanner were measured in this study. This scanner will be useful for animal imaging.
Subject(s)
Animals , Mice , Rats , AluminumABSTRACT
Objective To evaluate the performance parameters of the PET instrument, which has been used for years in our hospital, assuring the stability of image quality and performance parameters. Methods NEMA NU 2-1994 Standards was used as reference for performance measurement of PET, which were published by National Electrical Manufacturers Association(NEMA). The NEMA standard cylinder model, 18F radiation source, and 18F and 68Ge columniform radiation source were used. Results Projects for performance measurement and daily quality control were drawn up. Conclusion This project provides a reference and methods for the performance measurement of PET instrument and daily quality control. It better ensures the stability of image quality and performance parameters of the PET instrument.
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PURPOSE: NEMA NU2-2001 was proposed as a new standard for performance evaluation of whole body PET scanners. In this study, system performance of Siemens CTI ECAT EXACT 47 PET scanner including spatial resolution, sensitivity, scatter fraction, and count rate performance in 2D and 3D mode was evaluated using this new standard method. METHODS: ECAT EXACT 47 is a BGO crystal based PET scanner and covers an axial field of view (FOV) of 16.2 cm. Retractable septa allow 2D and 3D data acquisition. All the PET data were acquired according to the NEMA NU2-2001 protocols (coincidence window: 12 ns, energy window: 250 ~ 650 keV). For the spatial resolution measurement, F-18 point source was placed at the center of the axial FOV ( (a) x=0, and y=1, (b) x=0, and y=10, (c) x=10, and y=0cm) and a position one fourth of the axial FOV from the center ( (a) x=0, and y=1, (b) x=0, and y=10, (c) x=10, and y=0cm). In this case, x and y are transaxial horizontal and vertical, and z is the scanner's axial direction. Images were reconstructed using FBP with ramp filter without any post-processing. To measure the system sensitivity, NEMA sensitivity phantom filled with F-18 solution and surrounded by 1~5 aluminum sleeves were scanned at the center of transaxial FOV and 10 cm offset from the center. Attenuation free values of sensitivity were estimated by extrapolating data to the zero wall thickness. NEMA scatter phantom with length of 70 cm was filled with F-18 or C-11solution (2D: 2, 900 MBq, 3D: 407 MBq), and coincidence count rates were measured for 7 half-lives to obtain noise equivalent count rate (NECR) and scatter fraction. We confirmed that dead time loss of the last frame were below 1%. Scatter fraction was estimated by averaging the true to background (scatter + random) ratios of last 3 frames in which the fractions of random rate are negligibly small. RESULTS: Axial and transverse resolutions at 1cm offset from the center were 0.62 and 0.66 cm (FBP in 2D and 3D), and 0.67 and 0.69 cm (FBP in 2D and 3D). Axial, transverse radial, and transverse tangential resolutions at 10cm offset from the center were 0.72 and 0.68 cm (FBP in 2D and 3D), 0.63 and 0.66 cm (FBP in 2D and 3D), and 0.72 and 0.66 cm (FBP in 2D and 3D). Sensitivity values were 708.6 (2D), 2931.3 (3D) counts/sec/MBq at the center and 728.7 (2D), 3398.2 (3D) counts/sec/MBq at 10 cm offset from the center. Scatter fractions were 0.19 (2D) and 0.49 (3D). Peak true count rate and NECR were 64.0 kcps at 40.1 kBq/mL and 49.6 kcps at 40.1 kBq/mL in 2D and 53.7 kcps at 4.76 kBq/mL and 26.4 kcps at 4.47 kBq/mL in 3D. CONCLUSION: Information about the performance of CTI ECAT EXACT 47 PET scanner reported in this study will be useful for the quantitative analysis of data and determination of optimal image acquisition protocols using this widely used scanner for clinical and research purposes.
Subject(s)
Aluminum , Architectural Accessibility , NoiseABSTRACT
PURPOSE: Philips GEMINI is a newly introduced whole-body GSO PET/CT scanner. In this study, performance of the scanner including spatial resolution, sensitivity, scatter fraction, noise equivalent count ratio (NECR) was measured utilizing NEMA NU2-2001 standard protocol and compared with performance of LSO, BGO crystal scanner. METHODS: GEMINI is composed of the Philips ALLEGRO PET and MX8000 D multi-slice CT scanners. The PET scanner has 28 detector segments which have an array of 29 by 22 GSO crystals (4x6x20 mm), covering axial FOV of 18 cm. PET data to measure spatial resolution, sensitivity, scatter fraction, and NECR were acquired in 3D mode according to the NEMA NU2 protocols (coincidence window: 8 ns, energy window: 409~664 keV). For the measurement of spatial resolution, images were reconstructed with FBP using ramp filter and an iterative reconstruction algorithm, 3D RAMLA. Data for sensitivity measurement were acquired using NEMA sensitivity phantom filled with F-18 solution and surrounded by 1~5 aluminum sleeves after we confirmed that dead time loss did not exceed 1%. To measure NECR and scatter fraction, 1110 MBq of F-18 solution was injected into a NEMA scatter phantom with a length of 70 cm and dynamic scan with 20-min frame duration was acquired for 7 half-lives. Oblique sinograms were collapsed into transaxial slices using single slice rebinning method, and true to background (scatter + random) ratio for each slice and frame was estimated. Scatter fraction was determined by averaging the true to background ratio of last 3 frames in which the dead time loss was below 1%. RESULTS: Transverse and axial resolutions at 1cm radius were (1) 5.3 and 6.5 mm (FBP), (2) 5.1 and 5.9 mm (3D RAMLA). Transverse radial, transverse tangential, and axial resolution at 10 cm were (1) 5.7, 5.7, and 7.0 mm (FBP), (2) 5.4, 5.4, and 6.4 mm (3D RAMLA). Attenuation free values of sensitivity were 3, 620 counts/sec/MBq at the center of transaxial FOV and 4, 324 counts/sec/MBq at 10 cm offset from the center. Scatter fraction was 40.6%, and peak true count rate and NECR were 88.9 kcps @ 12.9 kBq/mL and 34.3 kcps @ 8.84 kBq/mL. These characteristics are better than that of ECAT EXACT PET scanner with BGO crystal. CONCLUSION: The results of this field test demonstrate high resolution, sensitivity and count rate performance of the 3D PET/CT scanner with GSO crystal. The data provided here will be useful for the comparative study with other 3D PET/CT scanners using BGO or LSO crystals.
Subject(s)
Aluminum , Architectural Accessibility , Noise , Positron Emission Tomography Computed Tomography , RadiusABSTRACT
Objective To test image quality, accuracy of attenuation and scattering corrections of PET with NEMA NU2-2001. Methods By using NEMA IEC/2001 PET Phantom,along with the test methods recommended by NEMA NU2-2001, the PET image quality, accuracy of attenuation and scatter corrections were measured. Results Relative error in attenuation and scatter corrections were 0.25 (n=4) and 0.25 (n=8) respectively. Conclusion It's difficulty to prepare the phantom and process data. Preparing the phantom according to the radioactivity ratio strictly and processing data carefully even with many times, the exact result of the test can be obtained.