The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David W Townsend - One of the best experts on this subject based on the ideXlab platform.
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hybrid pet ct and pet mri imaging of vulnerable coronary plaque and myocardial scar tissue in acute myocardial infarction
Journal of Nuclear Cardiology, 2018Co-Authors: Stephanie Marchesseau, David W Townsend, Aruni Seneviratna, Therese A Sjoholm, Jamie X M Ho, Derek J Hausenloy, Mark A Richards, John J Totman, Mark Y ChanAbstract:BACKGROUND: Following an acute coronary syndrome, combined CT and PET with 18F-NaF can identify coronary atherosclerotic plaques that have ruptured or eroded. However, the processes behind 18F-NaF uptake in vulnerable plaques remain unclear. METHODS AND RESULTS: Ten patients with STEMI were scanned after 18F-NaF injection, for 75 minutes in a Siemens PET/MR Scanner using delayed enhancement (LGE). They were then scanned in a Siemens PET/CT Scanner for 10 minutes. Tissue-to-background ratio (TBR) was compared between the culprit lesion in the IRA and remote non-culprit lesions in an effort to independently validate prior studies. Additionally, we performed a proof-of-principle study comparing TBR in scar tissue and remote myocardium using LGE images and PET/MR or PET/CT data. From the 33 coronary lesions detected on PET/CT, TBRs for culprit lesions were higher than for non-culprit lesions (TBR = 2.11 ± 0.45 vs 1.46 ± 0.48; P < 0.001). Interestingly, the TBR measured on the PET/CT was higher for infarcted myocardium than for remote myocardium (TBR = 0.81 ± 0.10 vs 0.71 ± 0.05; P = 0.003). These results were confirmed using the PET/MR data (TBR = 0.81 ± 0.10 for scar, TBR = 0.71 ± 0.06 for healthy myocardium, P = 0.03). CONCLUSIONS: We confirmed the potential of 18F-NaF PET/CT imaging to detect vulnerable coronary lesions. Moreover, we demonstrated proof-of-principle that 18F-NaF concurrently detects myocardial scar tissue.
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physical and clinical performance of the mct time of flight pet ct Scanner
Physics in Medicine and Biology, 2011Co-Authors: David W Townsend, Bjoern Jakoby, Y Bercier, Maurizio Conti, Michael E Casey, B BendriemAbstract:Time-of-flight (TOF) measurement capability promises to improve PET image quality. We characterized the physical and clinical PET performance of the first Biograph mCT TOF PET/CT Scanner (Siemens Medical Solutions USA, Inc.) in comparison with its predecessor, the Biograph TruePoint TrueV. In particular, we defined the improvements with TOF. The physical performance was evaluated according to the National Electrical Manufacturers Association (NEMA) NU 2-2007 standard with additional measurements to specifically address the TOF capability. Patient data were analyzed to obtain the clinical performance of the Scanner. As expected for the same size crystal detectors, a similar spatial resolution was measured on the mCT as on the TruePoint TrueV. The mCT demonstrated modestly higher sensitivity (increase by 19.7 ? 2.8%) and peak noise equivalent count rate (NECR) (increase by 15.5 ? 5.7%) with similar scatter fractions. The energy, time and spatial resolutions for a varying single count rate of up to 55 Mcps resulted in 11.5 ? 0.2% (FWHM), 527.5 ? 4.9 ps (FWHM) and 4.1 ? 0.0 mm (FWHM), respectively. With the addition of TOF, the mCT also produced substantially higher image contrast recovery and signal-to-noise ratios in a clinically-relevant phantom geometry. The benefits of TOF were clearly demonstrated in representative patient images.
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physical and clinical performance of the mct time of flight pet ct Scanner
Physics in Medicine and Biology, 2011Co-Authors: David W Townsend, Bjoern Jakoby, Y Bercier, Maurizio Conti, Michael E Casey, B BendriemAbstract:Time-of-flight (TOF) measurement capability promises to improve PET image quality. We characterized the physical and clinical PET performance of the first Biograph mCT TOF PET/CT Scanner (Siemens Medical Solutions USA, Inc.) in comparison with its predecessor, the Biograph TruePoint TrueV. In particular, we defined the improvements with TOF. The physical performance was evaluated according to the National Electrical Manufacturers Association (NEMA) NU 2-2007 standard with additional measurements to specifically address the TOF capability. Patient data were analyzed to obtain the clinical performance of the Scanner. As expected for the same size crystal detectors, a similar spatial resolution was measured on the mCT as on the TruePoint TrueV. The mCT demonstrated modestly higher sensitivity (increase by 19.7 ± 2.8%) and peak noise equivalent count rate (NECR) (increase by 15.5 ± 5.7%) with similar scatter fractions. The energy, time and spatial resolutions for a varying single count rate of up to 55 Mcps resulted in 11.5 ± 0.2% (FWHM), 527.5 ± 4.9 ps (FWHM) and 4.1 ± 0.0 mm (FWHM), respectively. With the addition of TOF, the mCT also produced substantially higher image contrast recovery and signal-to-noise ratios in a clinically-relevant phantom geometry. The benefits of TOF were clearly demonstrated in representative patient images.
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performance characteristics of a new lso pet ct Scanner with extended axial field of view and psf reconstruction
IEEE Transactions on Nuclear Science, 2009Co-Authors: Bjoern Jakoby, Charles C Watson, Y Bercier, B Bendriem, David W TownsendAbstract:A new combined lutetium oxyorthosilicate (LSO) PET/CT Scanner with an extended axial field-of-view (FOV) of 21.8 cm has been developed (Biograph TruePoint PET/CT with TrueV; Siemens Molecular Imaging) and introduced into clinical practice. The Scanner includes the recently announced point spread function (PSF) reconstruction algorithm. The PET components incorporate four rings of 48 detector blocks, 5.4 cm times 5.4 cm in cross-section. Each block comprises a 13 times 13 matrix of 4 times 4 times 20 mm3 elements. Data are acquired with a 4.5 ns coincidence time window and an energy window of 425-650 keV. The physical performance of the new Scanner has been evaluated according to the recently revised National Electrical Manufacturers Association (NEMA) NU 2-2007 standard and the results have been compared with a previous PET/CT design that incorporates three rings of block detectors with an axial coverage of 16.2 cm (Biograph TruePoint PET/CT; Siemens Molecular Imaging). In addition to the phantom measurements, patient Noise Equivalent Count Rates (NECRs) have been estimated for a range of patients with different body weights (42-154 kg). The average spatial resolution is the same for both Scanners: 4.4 mm (FWHM) and 5.0 mm (FWHM) at 1 cm and 10 cm respectively from the center of the transverse FOV. The scatter fractions of the Biograph TruePoint and Biograph TruePoint TrueV are comparable at 32%. Compared to the three ring design, the system sensitivity and peak NECR with smoothed randoms correction (1R) increase by 82% and 73%, respectively. The increase in sensitivity from the extended axial coverage of the Biograph TruePoint PET/CT with TrueV should allow a decrease in either scan time or injected dose without compromising diagnostic image quality. The contrast improvement with the PSF reconstruction potentially offers enhanced detectability for small lesions.
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performance investigation of a time of flight pet ct Scanner
IEEE Nuclear Science Symposium, 2008Co-Authors: Bjoern Jakoby, Y Bercier, Maurizio Conti, Michael E Casey, T Gremillion, Charles Hayden, B Bendriem, David W TownsendAbstract:The physical PET performance of the first prototype of the recently introduced Biograph mCT TOF PET/CT Scanner (Siemens Molecular Imaging) has been evaluated. The PET component incorporates 192 detector blocks, 5.4 cm x 5.4 cm in cross-section; each block comprises a 13 x 13 matrix of 4 x 4 x 20 mm3 crystal elements. The four detector block rings cover a 21.8 cm axial field-of-view with a 78 cm diameter patient port. Data are acquired within a 4.1 ns coincidence time window and with an energy threshold of 435–650 keV. The recent NEMA NU 2-2007 standard [1] was utilized to evaluate the preliminary physical performance of the Scanner with additional measurements that specifically addressed the TOF capability. An average spatial resolution of 4.4 mm (FWHM) and 5.2 mm (FWHM) were measured at 1 cm and 10 cm from the center of the transverse field-of-view. The system sensitivity for a line source was 0.96 % and 0.94 % respectively at 0 cm and 10 cm from the center of the transverse FOV. We report a scatter fraction of 32% and a noise equivalent count (NEC) rate peaking at more than 180 kcps. The energy and timing resolution were measured with a 18F line source resulting in 11.7% (FWHM) and less than 550 ps (FWHM) respectively. We observed no significant variation in time, energy and spatial resolution for a singles count rate of more than 45 Mcps.
Eugenio Inglese - One of the best experts on this subject based on the ideXlab platform.
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performance characteristics obtained for a new 3 dimensional lutetium oxyorthosilicate based whole body pet ct Scanner with the national electrical manufacturers association nu 2 2001 standard
The Journal of Nuclear Medicine, 2005Co-Authors: Marco Brambilla, Chiara Secco, Marco Dominietto, Roberta Matheoud, Gianmauro Sacchetti, Eugenio IngleseAbstract:This article reports the results of performance measurements obtained for the lutetium oxyorthosilicate (LSO)–based whole-body PET/CT Scanner Biograph 16 HI-REZ with the National Electrical Manufacturers Association (NEMA) NU 2-2001 standard. The Biograph 16 HI-REZ combines a multislice (16-slice) spiral CT Scanner with a PET Scanner composed of 24.336 LSO crystals arranged in 39 rings. The crystal dimensions are 4.0 × 4.0 × 20 mm3, and the crystals are organized in 13 × 13 blocks coupled to 4 photomultiplier tubes each. The 39 rings allow the acquisition of 81 images 2.0 mm thick, covering an axial field of view of 162 mm. The low- and high-energy thresholds are set to 425 and 650 keV, respectively, acquiring data within a 4.5-ns-wide coincidence window. Methods: Performance measurements for the LSO-based PET/CT Scanner were obtained with the NEMA NU 2-2001 standard, taking into account issues deriving from the presence of intrinsic radiation. Results: The results obtained with the NEMA NU 2-2001 standard measurements were as follows: average transverse and axial spatial resolutions (full width at half maximum) at 1 cm and at 10 cm off axis of 4.61 (5.10) mm and 5.34 (5.91) mm, respectively; average sensitivity of 4.92 counts per second per kilobecquerel for the 2 radial positions (0 and 10 cm); 34.1% system scatter fraction; and peak noise equivalent count (NEC) rates of 84.77 kilocounts per second (kcps) at 28.73 kBq/mL (k = 1 in the NEC formula; noiseless random correction) and 58.71 kcps at 21.62 kBq/mL (k = 2; noisy random correction). Conclusion: The new integrated PET/CT system Biograph 16 HI-REZ has good overall performance, with, in particular, a high resolution, a low scatter fraction, and a very good NEC response.
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performance characteristics obtained for a new 3 dimensional lutetium oxyorthosilicate based whole body pet ct Scanner with the national electrical manufacturers association nu 2 2001 standard
The Journal of Nuclear Medicine, 2005Co-Authors: Marco Brambilla, Chiara Secco, Marco Dominietto, Roberta Matheoud, Gianmauro Sacchetti, Eugenio IngleseAbstract:UNLABELLED: This article reports the results of performance measurements obtained for the lutetium oxyorthosilicate (LSO)-based whole-body PET/CT Scanner Biograph 16 HI-REZ with the National Electrical Manufacturers Association (NEMA) NU 2-2001 standard. The Biograph 16 HI-REZ combines a multislice (16-slice) spiral CT Scanner with a PET Scanner composed of 24.336 LSO crystals arranged in 39 rings. The crystal dimensions are 4.0x4.0x20 mm3, and the crystals are organized in 13x13 blocks coupled to 4 photomultiplier tubes each. The 39 rings allow the acquisition of 81 images 2.0 mm thick, covering an axial field of view of 162 mm. The low- and high-energy thresholds are set to 425 and 650 keV, respectively, acquiring data within a 4.5-ns-wide coincidence window. METHODS: Performance measurements for the LSO-based PET/CT Scanner were obtained with the NEMA NU 2-2001 standard, taking into account issues deriving from the presence of intrinsic radiation. RESULTS: The results obtained with the NEMA NU 2-2001 standard measurements were as follows: average transverse and axial spatial resolutions (full width at half maximum) at 1 cm and at 10 cm off axis of 4.61 (5.10) mm and 5.34 (5.91) mm, respectively; average sensitivity of 4.92 counts per second per kilobecquerel for the 2 radial positions (0 and 10 cm); 34.1% system scatter fraction; and peak noise equivalent count (NEC) rates of 84.77 kilocounts per second (kcps) at 28.73 kBq/mL (k=1 in the NEC formula; noiseless random correction) and 58.71 kcps at 21.62 kBq/mL (k=2; noisy random correction). CONCLUSION: The new integrated PET/CT system Biograph 16 HI-REZ has good overall performance, with, in particular, a high resolution, a low scatter fraction, and a very good NEC response.
Chao Wang - One of the best experts on this subject based on the ideXlab platform.
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engineering and performance nema and animal of a lower cost higher resolution animal pet ct Scanner using photomultiplier quadrant sharing detectors
The Journal of Nuclear Medicine, 2012Co-Authors: Wai Hoi Wong, Hossain Baghaei, Yuxuan Zhang, Rocio Ramirez, Shitao Liu, Chao WangAbstract:The dedicated murine PET (MuPET) Scanner is a high-resolution, high-sensitivity, and low-cost preclinical PET camera designed and manufactured at our laboratory. In this article, we report its performance according to the NU 4-2008 standards of the National Electrical Manufacturers Association (NEMA). We also report the results of additional phantom and mouse studies. Methods: The MuPET Scanner, which is integrated with a CT camera, is based on the photomultiplier-quadrant-sharing concept and comprises 180 blocks of 13 × 13 lutetium yttrium oxyorthosilicate crystals (1.24 × 1.4 × 9.5 mm3) and 210 low-cost 19-mm photomultipliers. The camera has 78 detector rings, with an 11.6-cm axial field of view and a ring diameter of 16.6 cm. We measured the energy resolution, scatter fraction, sensitivity, spatial resolution, and counting rate performance of the Scanner. In addition, we scanned the NEMA image-quality phantom, Micro Deluxe and Ultra-Micro Hot Spot phantoms, and 2 healthy mice. Results: The system average energy resolution was 14% at 511 keV. The average spatial resolution at the center of the field of view was about 1.2 mm, improving to 0.8 mm and remaining below 1.2 mm in the central 6-cm field of view when a resolution-recovery method was used. The absolute sensitivity of the camera was 6.38% for an energy window of 350–650 keV and a coincidence timing window of 3.4 ns. The system scatter fraction was 11.9% for the NEMA mouselike phantom and 28% for the ratlike phantom. The maximum noise-equivalent counting rate was 1,100 at 57 MBq for the mouselike phantom and 352 kcps at 65 MBq for the ratlike phantom. The 1-mm fillable rod was clearly observable using the NEMA image-quality phantom. The images of the Ultra-Micro Hot Spot phantom also showed the 1-mm hot rods. In the mouse studies, both the left and right ventricle walls were clearly observable, as were the Harderian glands. Conclusion: The MuPET camera has excellent resolution, sensitivity, counting rate, and imaging performance. The data show it is a powerful Scanner for preclinical animal study and pharmaceutical development.
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engineering and performance nema and animal of a lower cost higher resolution animal pet ct Scanner using photomultiplier quadrant sharing detectors
The Journal of Nuclear Medicine, 2012Co-Authors: Wai Hoi Wong, Hossain Baghaei, Yuxuan Zhang, Rocio Ramirez, Shitao Liu, Chao WangAbstract:UNLABELLED The dedicated murine PET (MuPET) Scanner is a high-resolution, high-sensitivity, and low-cost preclinical PET camera designed and manufactured at our laboratory. In this article, we report its performance according to the NU 4-2008 standards of the National Electrical Manufacturers Association (NEMA). We also report the results of additional phantom and mouse studies. METHODS The MuPET Scanner, which is integrated with a CT camera, is based on the photomultiplier-quadrant-sharing concept and comprises 180 blocks of 13 × 13 lutetium yttrium oxyorthosilicate crystals (1.24 × 1.4 × 9.5 mm(3)) and 210 low-cost 19-mm photomultipliers. The camera has 78 detector rings, with an 11.6-cm axial field of view and a ring diameter of 16.6 cm. We measured the energy resolution, scatter fraction, sensitivity, spatial resolution, and counting rate performance of the Scanner. In addition, we scanned the NEMA image-quality phantom, Micro Deluxe and Ultra-Micro Hot Spot phantoms, and 2 healthy mice. RESULTS The system average energy resolution was 14% at 511 keV. The average spatial resolution at the center of the field of view was about 1.2 mm, improving to 0.8 mm and remaining below 1.2 mm in the central 6-cm field of view when a resolution-recovery method was used. The absolute sensitivity of the camera was 6.38% for an energy window of 350-650 keV and a coincidence timing window of 3.4 ns. The system scatter fraction was 11.9% for the NEMA mouselike phantom and 28% for the ratlike phantom. The maximum noise-equivalent counting rate was 1,100 at 57 MBq for the mouselike phantom and 352 kcps at 65 MBq for the ratlike phantom. The 1-mm fillable rod was clearly observable using the NEMA image-quality phantom. The images of the Ultra-Micro Hot Spot phantom also showed the 1-mm hot rods. In the mouse studies, both the left and right ventricle walls were clearly observable, as were the Harderian glands. CONCLUSION The MuPET camera has excellent resolution, sensitivity, counting rate, and imaging performance. The data show it is a powerful Scanner for preclinical animal study and pharmaceutical development.
Charles C Watson - One of the best experts on this subject based on the ideXlab platform.
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performance characteristics of a new lso pet ct Scanner with extended axial field of view and psf reconstruction
IEEE Transactions on Nuclear Science, 2009Co-Authors: Bjoern Jakoby, Charles C Watson, Y Bercier, B Bendriem, David W TownsendAbstract:A new combined lutetium oxyorthosilicate (LSO) PET/CT Scanner with an extended axial field-of-view (FOV) of 21.8 cm has been developed (Biograph TruePoint PET/CT with TrueV; Siemens Molecular Imaging) and introduced into clinical practice. The Scanner includes the recently announced point spread function (PSF) reconstruction algorithm. The PET components incorporate four rings of 48 detector blocks, 5.4 cm times 5.4 cm in cross-section. Each block comprises a 13 times 13 matrix of 4 times 4 times 20 mm3 elements. Data are acquired with a 4.5 ns coincidence time window and an energy window of 425-650 keV. The physical performance of the new Scanner has been evaluated according to the recently revised National Electrical Manufacturers Association (NEMA) NU 2-2007 standard and the results have been compared with a previous PET/CT design that incorporates three rings of block detectors with an axial coverage of 16.2 cm (Biograph TruePoint PET/CT; Siemens Molecular Imaging). In addition to the phantom measurements, patient Noise Equivalent Count Rates (NECRs) have been estimated for a range of patients with different body weights (42-154 kg). The average spatial resolution is the same for both Scanners: 4.4 mm (FWHM) and 5.0 mm (FWHM) at 1 cm and 10 cm respectively from the center of the transverse FOV. The scatter fractions of the Biograph TruePoint and Biograph TruePoint TrueV are comparable at 32%. Compared to the three ring design, the system sensitivity and peak NECR with smoothed randoms correction (1R) increase by 82% and 73%, respectively. The increase in sensitivity from the extended axial coverage of the Biograph TruePoint PET/CT with TrueV should allow a decrease in either scan time or injected dose without compromising diagnostic image quality. The contrast improvement with the PSF reconstruction potentially offers enhanced detectability for small lesions.
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optimizing injected dose in clinical pet by accurately modeling the counting rate response functions specific to individual patient scans
The Journal of Nuclear Medicine, 2005Co-Authors: Charles C Watson, David W Townsend, Michael E Casey, Bernard Bendriem, Jonathan Carney, Stefan Eberl, Steve Meikle, Frank DifilippoAbstract:To optimize the injected dose of radiopharmaceutical in PET, one needs to know its relationship to some metric of data quality for individual patient scans, such as noise-equivalent counting rate (NECR). In this paper, we show how one may accurately model the clinical NECR response corresponding to specific patient scans much as if a counting-rate test had been performed on each patient. We apply this technique to patient data and show how it can lead to improved clinical scanning protocols. Methods: True and random coincidence rates expressed as functions of an appropriate measurable system parameter such as the detector single-event rate have functional forms that are largely independent of the object being scanned. Thus, reference true and random response functions may be scaled directly to the specific counting rates measured on a clinical scan, thereby yielding a curve of NECR versus injected dose. We have applied this technique to 2 groups of 163 clinical 18 F-FDG scans each. One of the groups was obtained on a lutetium oxyorthosilicate PET/CT Scanner with conventional front-end electronics, and the other was obtained on a lutetium oxyorthosilicate PET/CT Scanner with a new digital data processing system (Pico-3D). Results: At 90%‐95% of maximum signal-to-noise ratio (SNR), the mean optimal dose for a 60-min uptake period ranged from 366 to 717 MBq depending on the electronics and randoms processing method. There was only a slight (1 MBq/kg) dependence of optimal dose on patient weight but a larger dependence on position in the body. Pico-3D electronics improved optimal data SNR by 35% for a 70-kg person, but in both cases NECR fell rapidly with increasing weight (1.4%/kg). For an equivalent data SNR, a 120-kg person would have to be scanned 2.3 times longer than a 60-kg person. Over this range of weight, the mean scatter fraction increased by 12% whereas the ratio of mean randoms to trues increased by 48%. Conclusion: The methodology developed here allows one to directly estimate the optimal dose to inject for specific clinical scans and permits a detailed analysis of the sources of noise in PET data and of their variation with parameters such as patient weight.
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pet performance measurements for an lso based combined pet ct Scanner using the national electrical manufacturers association nu 2 2001 standard
The Journal of Nuclear Medicine, 2004Co-Authors: Yusuf E Erdi, Sadek A Nehmeh, Tim Mulnix, John L Humm, Charles C WatsonAbstract:UNLABELLED: Results of performance measurements for a lutetium oxyorthosilicate (LSO)-based PET/CT Scanner using new National Electrical Manufacturers Association (NEMA) NU 2-2001 standards are reported. METHODS: Performance measurements following the NU 2-2001 standards were performed on an LSO-based PET/CT Scanner. In addition, issues associated with the application of the NEMA standard to LSO-based tomographs in the presence of intrinsic radiation are discussed. RESULTS: We report on some difficulties experienced in following the suggested NEMA measurement techniques and describe alternative approaches. Measurements with the new standard (as compared with NU-1994) incorporate the effects of activity outside the Scanner and facilitate measurements of the entire axial field of view. Realistic clinical conditions are also simulated in image quality measurements of a torso phantom. CONCLUSION: We find that, with appropriate modifications, NU 2-2001 can be successfully applied to LSO-based Scanners.
Paul E Christian - One of the best experts on this subject based on the ideXlab platform.
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pet ct Scanner validation for clinical trials reasons for failure recipes for success the clinical trials network ctn experience
The Journal of Nuclear Medicine, 2015Co-Authors: John Sunderland, Paul E Christian, Tina KissAbstract:1737 Objectives Phantom validation of quantitative accuracy and image quality of a PET/CT Scanner is often the first step in site qualification for clinical trial participation. The SNMMI CTN has analyzed over 400 Scanner validations performed with the CTN oncology phantom. Of these submissions, 20% of studies fail to pass acceptance criteria. The objective of this retrospective study is to identify and classify the reasons for failure to better prepare sites for qualification and to aid in site selection. Methods Records from 421 phantom scans submitted to CTN between 2009 and 2014 were reviewed to identify causes of failures. Seven categories for failure were tallied: 1) Missing information; 2) Phantom filling and activity measurement; 3) Data entry; 4) Scanner calibration/dose calibrator; 5) Image quality/lesion detectability; 6) PET/CT misalignment; 7) Image artifacts. Each site was classified as “academic” or “non-academic” based on the availability of full-time on-site physics support. Results 170 imaging sites performed the 421 phantom scans reviewed. 41% of sites were classified as academic and 59% non-academic. Academic sites failed Scanner validation 12% of the time, but all passed on rescan. Non-academic sites failed validation 31% of the time, and with some frequency also failed rescan. The most frequent failure (42% of all errors, 10% of all phantom scans) was due to technical errors in phantom filling, imaging, or reconstruction. The 2nd most frequent failure was unacceptable Scanner calibration (27% of all errors, 6% of all phantom scans). The frequency distribution of error category (1-7) was nearly identical between academic and non-academic sites. Conclusions Non-academic sites suffered disqualifying errors at nearly 3-times the rate of academic sites. Executing technical instructions for phantom filling and imaging proved the most significant challenge. The results suggest that academic sites have a higher probability of first-pass validation success than their non-academic counterparts. Research Support None
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quantitative pet ct Scanner performance characterization based upon the society of nuclear medicine and molecular imaging clinical trials network oncology clinical simulator phantom
The Journal of Nuclear Medicine, 2015Co-Authors: John Sunderland, Paul E ChristianAbstract:The Clinical Trials Network (CTN) of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) operates a PET/CT phantom imaging program using the CTN’s oncology clinical simulator phantom, designed to validate Scanners at sites that wish to participate in oncology clinical trials. Since its inception in 2008, the CTN has collected 406 well-characterized phantom datasets from 237 Scanners at 170 imaging sites covering the spectrum of commercially available PET/CT systems. The combined and collated phantom data describe a global profile of quantitative performance and variability of PET/CT data used in both clinical practice and clinical trials. Methods: Individual sites filled and imaged the CTN oncology PET phantom according to detailed instructions. Standard clinical reconstructions were requested and submitted. The phantom itself contains uniform regions suitable for Scanner calibration assessment, lung fields, and 6 hot spheric lesions with diameters ranging from 7 to 20 mm at a 4:1 contrast ratio with primary background. The CTN Phantom Imaging Core evaluated the quality of the phantom fill and imaging and measured background standardized uptake values to assess Scanner calibration and maximum standardized uptake values of all 6 lesions to review quantitative performance. Scanner make-and-model–specific measurements were pooled and then subdivided by reconstruction to create Scanner-specific quantitative profiles. Results: Different makes and models of Scanners predictably demonstrated different quantitative performance profiles including, in some cases, small calibration bias. Differences in site-specific reconstruction parameters increased the quantitative variability among similar Scanners, with postreconstruction smoothing filters being the most influential parameter. Quantitative assessment of this intraScanner variability over this large collection of phantom data gives, for the first time, estimates of reconstruction variance introduced into trials from allowing trial sites to use their preferred reconstruction methodologies. Predictably, time-of-flight–enabled Scanners exhibited less size-based partial-volume bias than non–time-of-flight Scanners. Conclusion: The CTN Scanner validation experience over the past 5 y has generated a rich, well-curated phantom dataset from which PET/CT make-and-model and reconstruction-dependent quantitative behaviors were characterized for the purposes of understanding and estimating Scanner-based variances in clinical trials. These results should make it possible to identify and recommend make-and-model–specific reconstruction strategies to minimize measurement variability in cancer clinical trials.
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quantitative pet ct Scanner performance characterization based upon the society of nuclear medicine and molecular imaging clinical trials network oncology clinical simulator phantom
The Journal of Nuclear Medicine, 2015Co-Authors: John Sunderland, Paul E ChristianAbstract:UNLABELLED: The Clinical Trials Network (CTN) of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) operates a PET/CT phantom imaging program using the CTN's oncology clinical simulator phantom, designed to validate Scanners at sites that wish to participate in oncology clinical trials. Since its inception in 2008, the CTN has collected 406 well-characterized phantom datasets from 237 Scanners at 170 imaging sites covering the spectrum of commercially available PET/CT systems. The combined and collated phantom data describe a global profile of quantitative performance and variability of PET/CT data used in both clinical practice and clinical trials. METHODS: Individual sites filled and imaged the CTN oncology PET phantom according to detailed instructions. Standard clinical reconstructions were requested and submitted. The phantom itself contains uniform regions suitable for Scanner calibration assessment, lung fields, and 6 hot spheric lesions with diameters ranging from 7 to 20 mm at a 4:1 contrast ratio with primary background. The CTN Phantom Imaging Core evaluated the quality of the phantom fill and imaging and measured background standardized uptake values to assess Scanner calibration and maximum standardized uptake values of all 6 lesions to review quantitative performance. Scanner make-and-model-specific measurements were pooled and then subdivided by reconstruction to create Scanner-specific quantitative profiles. RESULTS: Different makes and models of Scanners predictably demonstrated different quantitative performance profiles including, in some cases, small calibration bias. Differences in site-specific reconstruction parameters increased the quantitative variability among similar Scanners, with postreconstruction smoothing filters being the most influential parameter. Quantitative assessment of this intraScanner variability over this large collection of phantom data gives, for the first time, estimates of reconstruction variance introduced into trials from allowing trial sites to use their preferred reconstruction methodologies. Predictably, time-of-flight-enabled Scanners exhibited less size-based partial-volume bias than non-time-of-flight Scanners. CONCLUSION: The CTN Scanner validation experience over the past 5 y has generated a rich, well-curated phantom dataset from which PET/CT make-and-model and reconstruction-dependent quantitative behaviors were characterized for the purposes of understanding and estimating Scanner-based variances in clinical trials. These results should make it possible to identify and recommend make-and-model-specific reconstruction strategies to minimize measurement variability in cancer clinical trials.