Performance Evaluation of the FLEX Triumph X-PET Scanner Using the National Electrical Manufacturers Association NU-4 Standards

Prasad, Rameshwar; Ratib, Osman; Zaidi, Habib

doi:10.2967/jnumed.110.076125

Cited by 44 publications

(53 citation statements)

References 32 publications

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“…This effect could possibly be attributed to an overshoot at the edges, commonly referred to as the Gibbs effect (29,32). The measured activities in cold regions, that is, the water-and air-filled inserts, for enhanced-resolution mode without postfiltering processing were comparable to data obtained with another scanner (28), suggesting that corrections for attenuation and scatter were done appropriately. In general, preclinical PET attenuation correction is done with CT or with a 57 Co point source by singles detection.…”

Section: Discussionsupporting

confidence: 62%

“…This was somewhat higher than the scatter fractions of currently available preclinical PET scanners (3,28,29), possibly because of the large solid angle of this dedicated breast PET camera and the low-energy threshold for the third and the fourth crystal layers. The energy window of the third and fourth layers was set to 100-800 keV for maintenance of sensitivity.…”

Section: Discussionmentioning

confidence: 83%

“…Among several cameras that have been evaluated with NEMA NU 4 standards (3,24,28), the present dedicated breast camera provided comparable or higher visual contrast with acceptable uniformity in enhanced-resolution mode, and comparable or slightly lower contrast with excellent uniformity in standard mode. Such a property may increase the detectability of tumors, contribute to the evaluation of intratumoral morphologic and metabolic characteristics, and improve the quantification of 18 F-FDG uptake.…”

Section: Discussionmentioning

confidence: 99%

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Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards

et al. 2014

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The aim of this work was to evaluate the performance characteristics of a newly developed dedicated breast PET scanner, according to National Electrical Manufacturers Association (NEMA) NU 4-2008 standards. Methods: The dedicated breast PET scanner consists of 4 layers of a 32 · 32 lutetium oxyorthosilicate-based crystal array, a light guide, and a 64-channel position-sensitive photomultiplier tube. The size of a crystal element is 1.44 · 1.44 · 4.5 mm. The detector ring has a large solid angle with a 185-mm aperture and an axial coverage of 155.5 mm. The energy windows at depth of interaction for the first and second layers are 400-800 keV, and those at the third and fourth layers are 100-800 keV. A fixed timing window of 4.5 ns was used for all acquisitions. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with NEMA NU 4-2008 standards. Human imaging was performed in addition to the evaluation. Results: Radial, tangential, and axial spatial resolution measured as minimal full width at half maximum approached 1.6, 1.7, and 2.0 mm, respectively, for filtered backprojection reconstruction and 0.8, 0.8, and 0.8 mm, respectively, for dynamic row-action maximum-likelihood algorithm reconstruction. The peak absolute sensitivity of the system was 11.2%. Scatter fraction at the same acquisition settings was 30.1% for the rat-sized phantom. Peak noise-equivalent counting rate and peak true rate for the ratlike phantom was 374 kcps at 25 MBq and 603 kcps at 31 MBq, respectively. In the image-quality phantom study, recovery coefficients and uniformity were 0.04-0.82 and 1.9%, respectively, for standard reconstruction mode and 0.09-0.97 and 4.5%, respectively, for enhanced-resolution mode. Human imaging provided highcontrast images with restricted background noise for standard reconstruction mode and high-resolution images for enhancedresolution mode. Conclusion: The dedicated breast PET scanner has excellent spatial resolution and high sensitivity. The performance of the dedicated breast PET scanner is considered to be reasonable enough to support its use in breast cancer imaging. Br east cancer is one of the leading causes of cancer death among women worldwide, accounting for 425,000 deaths in 187 countries in 2010 (1). A strategy for reducing breast cancer mortality is early detection for successful treatment. PET systems dedicated to the breast have been under development since 1994, when Thompson et al. reported the feasibility of the first of these systems (2). The dedicated PET systems are intended to have higher photon sensitivity and improved spatial resolution by bringing the detectors close to the breast and by using smaller detector elements than those for whole-body tomography. Most of the dedicated PET systems perform positron emission mammography with 2 planar or curved detector heads that can compress the breast mildly, providing planar and limited-angle tomography images (3-8). Fully tomographic dedicated PET systems have also been introduced. This...

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

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Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards

et al. 2014

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“…These methods are widely used and validated on clinical PET systems [11]; however, they still need to be thoroughly investigated on dedicated high resolution, small field-of-view scanners such as those used for small-animal imaging. The quantitative capabilities of the commercially available FLEX Triumph™ (Gamma Medica-Ideas, Nortridge, CA) preclinical PET/CT platform installed in our department are being characterized [12]; however, the lack of reliable image correction methodologies necessitated the implementation of CTAC on this system as a first step to achieve our endeavors. In this work, we implemented and evaluated tube voltage-dependent attenuation correction on this preclinical PET/CT scanner.…”

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confidence: 99%

CT-Based Attenuation Correction on the FLEX Triumph Preclinical PET/CT Scanner

Prasad

Ratib

et al. 2011

IEEE Trans. Nucl. Sci.

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Abstract-Positron Emission Tomography (PET) has emerged as a valuable molecular imaging modality for quantitative measurement of biochemical processes in vivo in the clinical and preclinical imaging domains. However, PET imaging suffers from various physical degrading factors including photon attenuation, which can be corrected using CT-based attenuation correction (CTAC) on combined PET/CT scanners. The attenuation map is calculated by converting CT numbers derived from low-energy polyenergetic x-ray spectra to linear attenuation coefficients at 511 keV. Generation of accurate attenuation maps is crucial for reliable attenuation correction of PET data and hence is a prerequisite for accurate quantification of biological processes. For low concentrations of K 2 HPO 4 , the mean relative difference (in %) between theoretical and calculated attenuation coefficients when using bilinear and quadratic energy-mapping methods are 1 39 1 9 and 1 33 1 8, respectively. They are 2 78 1 3 and 2 5 1 3, respectively, for high concentrations of K 2 HPO 4 .As expected, higher activity concentrations were obtained for PET after attenuation correction. The increased PET signal for mouse tissues ranged between 21 and 31% for bilinear energy-mapping and between 21.8 and 35% for quadratic energy-mapping, whereas these varied from 40 to 51% and from 41 to 56%, respec- H. Zaidi is with the Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva, Switzerland and also with the Geneva Neuroscience Center, Geneva University, CH-1211 Geneva, Switzerland (e-mail: habib.zaidi@hcuge.ch).Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org.Digital Object Identifier 10.1109/TNS.2010.2087416tively, for rat tissues. For biological tissues having a high atomic number such as bone, the quadratic energy-mapping method produced slightly improved results compared to the bilinear energy-mapping method. Phantom and rodent PET studies were successfully corrected for photon attenuation using the developed CTAC procedure.

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“…A large number of small-animal Single Photon Emission Computed Tomography (SPECT) [1][2][3][4][5] and Positron Emission Tomography (PET) [6][7][8][9][10][11][12][13][14][15] systems have been developed and have become commercially available during the past years. Moreover, multimodality imaging has emerged as an important tool in Nuclear Medicine both for diagnostic and therapy follow up imaging.…”

Section: Iintroductionmentioning

confidence: 99%

ALBIRA: A small animal PET/SPECT/CT imaging system

et al. 2013

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Abstract:Purpose: We have developed a trimodal PET/SPECT/CT scanner for small animal imaging. The gamma ray sub-systems are based on monolithic crystals coupled to multi-anode photomultiplier tubes (MA-PMTs), while CT comprises a commercially available micro-focus X-ray tube and a CsI scintillator 2D pixelated flat panel X-ray detector. In this study we will report on the design and performance evaluation of the multimodal system. Methods: X-ray transmission measurements are performed based on cone-beam geometry. Individual projections were acquired by rotating the X-ray tube and the 2D flat panel detector, thus making possible a transaxial FOV of roughly 80 mm in diameter and an axial FOV of 65 mm for the CT system. The SPECT component has a dual head detector geometry mounted on a rotating gantry. The distance between the SPECT module detectors can be varied in order to optimize specific user requirements, including variable FOV. The PET system is made up of eight compact modules forming an octagon with an axial Field Of View (FOV) of 40 mm and a transaxial FOV of 80 mm in diameter. The main CT image quality parameters (spatial resolution and uniformity) have been determined. In the case of the SPECT, the tomographic spatial resolution and system sensitivity have been evaluated with a 99m Tc solution using single-pinhole and multipinhole collimators. PET and SPECT images were reconstructed using threedimensional (3D) Maximum Likelihood and Ordered Subset Expectation Maximization (MLEM and OSEM)) algorithms developed by the authors, whereas the CT images were obtained using a 3D based FBP algorithm.Results: CT spatial resolution was 85 μm while a uniformity of 2.7% was obtained for a water filled phantom at 45 kV. The SPECT spatial resolution was better than 0.8 mm measured with a Derenzo-like phantom for a FOV of 20 mm using a 1-mm pinhole aperture collimator. The full width at half-maximum (FWHM) PET radial spatial resolution at the center of the field of view was 1.55 mm. The SPECT system sensitivity for a FOV of 20 mm and 15% energy window was 700 cps/MBq (7.8x10 -2 %) using a multi-pinhole equipped with 5 apertures 1 mm in diameter, whereas the PET absolute sensitivity was 2% for a 350-650 keV energy window and a 5 ns timing window. Several animal images are also presented. Conclusions:The new small animal PET/SPECT/CT proposed here exhibits high performance, producing high-quality images suitable for studies with small animals. Monolithic design for PET and SPECT scintillator crystals reduces cost and complexity without significant performance degradation.

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Performance Evaluation of the FLEX Triumph X-PET Scanner Using the National Electrical Manufacturers Association NU-4 Standards

Cited by 44 publications

References 32 publications

Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards

Performance Evaluation of a New Dedicated Breast PET Scanner Using NEMA NU4-2008 Standards

CT-Based Attenuation Correction on the FLEX Triumph Preclinical PET/CT Scanner

ALBIRA: A small animal PET/SPECT/CT imaging system

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