scholarly journals Evaluation of image quality with four positron emitters and three preclinical PET/CT systems

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jarmo Teuho ◽  
Leon Riehakainen ◽  
Aake Honkaniemi ◽  
Olli Moisio ◽  
Chunlei Han ◽  
...  
Keyword(s):  
Image Quality ◽  
Small Animal ◽  
Quality Parameters ◽  
Acquisition Time ◽  
Image Quantification ◽  
Recovery Coefficient ◽  
Positron Range ◽  
Positron Emission ◽  
Pet Ct ◽  
Positron Emitters

Abstract Background We investigated the image quality of 11C, 68Ga, 18F and 89Zr, which have different positron fractions, physical half-lifes and positron ranges. Three small animal positron emission tomography/computed tomography (PET/CT) systems were used in the evaluation, including the Siemens Inveon, RAYCAN X5 and Molecubes β-cube. The evaluation was performed on a single scanner level using the national electrical manufacturers association (NEMA) image quality phantom and analysis protocol. Acquisitions were performed with the standard NEMA protocol for 18F and using a radionuclide-specific acquisition time for 11C, 68Ga and 89Zr. Images were assessed using percent recovery coefficient (%RC), percentage standard deviation (%STD), image uniformity (%SD), spill-over ratio (SOR) and evaluation of image quantification. Results 68Ga had the lowest %RC (< 62%) across all systems. 18F had the highest maximum %RC (> 85%) and lowest %STD for the 5 mm rod across all systems. For 11C and 89Zr, the maximum %RC was close (> 76%) to the %RC with 18F. A larger SOR were measured in water with 11C and 68Ga compared to 18F on all systems. SOR in air reflected image reconstruction and data correction performance. Large variation in image quantification was observed, with maximal errors of 22.73% (89Zr, Inveon), 17.54% (89Zr, RAYCAN) and − 14.87% (68Ga, Molecubes). Conclusions The systems performed most optimal in terms of NEMA image quality parameters when using 18F, where 11C and 89Zr performed slightly worse than 18F. The performance was least optimal when using 68Ga, due to large positron range. The large quantification differences prompt optimization not only by terms of image quality but also quantification. Further investigation should be performed to find an appropriate calibration and harmonization protocol and the evaluation should be conducted on a multi-scanner and multi-center level.

scholarly journals Influence of detectors efficiency normalization on small animal PET image quality

2019 ◽  
Vol 7 (3) ◽  
Author(s):  
Mateus Gesulado Carneiro De Santana ◽  
Guilherme Cavalcante de Albuquerque Souza ◽  
Rodrigo Modesto Gadelha Gontijo ◽  
Bruno Melo Mendes ◽  
Andréa Vidal Ferreira
Keyword(s):  
Image Quality ◽  
Image Acquisition ◽  
Small Animal ◽  
Quality Parameters ◽  
Small Animal Pet ◽  
Daily Routine ◽  
Positron Emission Tomograph ◽  
Software Update ◽  
Positron Emission ◽  
Compromise Image Quality

LabPET GE 4 (a small animal positron emission tomograph) image acquisition is done by 1536 independents channels. Differences in the rate counting of each channel must be corrected so as not compromise image quality. Equipment user manual recommends that normalization of the detectors efficiency be made as often as possible and always whenever there are hardware or software parameters changes - included, but not limited to channels parameters adjustments, electronic cards replacements, channels activation or inactivation or software update. This work evaluates the normalization effects on the image quality parameters. PET image acquisition were performed using recommended parameters by the NEMA NU 4-2008 standards. Image was reconstructed in different ways using different normalization files. The tests performed indicated that the image quality parameters do not vary significantly with different normalization data. Therefore, a daily routine of normalizations is not justified, suggesting a periodical frequency of one month or more for this procedure.

scholarly journals Head-to-head comparison of a Si-photomultiplier-based and a conventional photomultiplier-based PET-CT system

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jenny Oddstig ◽  
Gustav Brolin ◽  
Elin Trägårdh ◽  
David Minarik
Keyword(s):  
Image Quality ◽  
Acquisition Time ◽  
Reconstruction Algorithms ◽  
Ct Scanner ◽  
Recovery Coefficient ◽  
Reconstruction Methods ◽  
Pet Ct ◽  
Significant Difference ◽  
Ct System ◽  
Bed Position

Abstract Background A novel generation of PET scanners based on silicon (Si)-photomultiplier (PM) technology has recently been introduced. Concurrently, there has been development of new reconstruction methods aimed at increasing the detectability of small lesions without increasing image noise. The combination of new detector technologies and new reconstruction algorithms has been found to increase image quality. However, it is unknown to what extent the demonstrated improvement of image quality is due to scanner hardware development or improved reconstruction algorithms. To isolate the contribution of the hardware, this study aimed to compare the ability to detect small hotspots in phantoms using the latest generation SiPM-based PET/CT scanner (GE Discovery MI) relative to conventional PM-based PET/CT scanner (GE Discovery 690), using identical reconstruction protocols. Materials and methods Two different phantoms (NEMA body and Jasczcak) with fillable spheres (31 μl to 26.5 ml) and varying sphere-to-background-ratios (SBR) were scanned in one bed position for 15–600 s on both scanners. The data were reconstructed using identical reconstruction parameters on both scanners. The recovery-coefficient (RC), noise level, contrast (spherepeak/backgroundpeak-value), and detectability of each sphere were calculated and compared between the scanners at each acquisition time. Results The RC-curves for the NEMA phantom were near-identical for both scanners at SBR 10:1. For smaller spheres in the Jaszczak phantom, the contrast was 1.22 higher for the DMI scanner at SBR 15:1. The ratio decreased for lower SBR, with a ratio of 1.03 at SBR 3.85:1. Regarding the detectability of spheres, the sensitivity was 98% and 88% for the DMI and D690, respectively, for SBR 15:1. For SBR 7.5, the sensitivity was 75% and 83% for the DMI and D690, respectively. For SBR 3.85:1, the sensitivity was 43% and 30% for the DMI and D690, respectively. Conclusion Marginally higher contrast in small spheres was seen for the SiPM-based scanner but there was no significant difference in detectability between the scanners. It was difficult to detect differences between the scanners, suggesting that the SiPM-based detectors are not the primary reason for improved image quality.

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

2014 ◽  
Vol 59 (11) ◽  
pp. 2727-2746 ◽  
Author(s):  
Imre Lajtos ◽  
Johannes Czernin ◽  
Magnus Dahlbom ◽  
Freddie Daver ◽  
Miklos Emri ◽  
...  
Keyword(s):  
Image Quality ◽  
Small Animal ◽  
Wall Effect ◽  
Small Animal Pet ◽  
Cold Wall ◽  
Recovery Coefficient ◽  
Animal Pet ◽  
Pet Scanners

An Automatic System for Analyzing Phantom Images to Determine the Reliability of PET/SPECT Cameras

2015 ◽  
Author(s):  
Miri Weiss Cohen ◽  
John A. Kennedy ◽  
Archil Pirmisashvili ◽  
Gleb Orlikov
Keyword(s):  
Quality Control ◽  
Image Quality ◽  
Spatial Resolution ◽  
Automatic System ◽  
Quality Parameters ◽  
Tomographic Image ◽  
Performance Parameters ◽  
Pet Ct ◽  
Ct Scanners

This paper describes an automatic system for analyzing phantom images from two types of PET/CT scanners. The system was developed for the purpose of obtaining tomographic image quality parameters, which determine a number of different performance parameters, primarily scanner sensitivity, tomographic uniformity, contrast and spatial resolution. The system provides a method for generating and altering image masks used for the analysis of PET images, which are then automatically aligned with the PET data. The system automatically generates Quality Control (QC) reports and is currently being used at clinical PET/CT center.

Acquisition Protocols to Optimize 68Ga-DOTA-NOC Position Emission Tomography/Computer Tomography Image Quality Based on Patient Body Mass Index and Injected Dose

2020 ◽  
Vol 10 (2) ◽  
pp. 508-514
Author(s):  
Lei Xu ◽  
Lei Lei Zhou ◽  
Zhenyu Zhao ◽  
Qingle Meng ◽  
Rui Yang ◽  
...  
Keyword(s):  
Image Quality ◽  
Dose Group ◽  
Group Versus ◽  
Normal Weight ◽  
Emission Tomography ◽  
Acquisition Time ◽  
Position Emission Tomography ◽  
Weight Group ◽  
Pet Ct ◽  
Overweight Group

Background: The choice of 68Ga-DOTA-1-Nal3-octreotide (68Ga-DOTA-NOC) injected dose and Position emission tomography/computer tomography (PET/CT) acquisition time is still a challenge for obtaining consistently high-quality PET image. Objective: To determine the optimal acquisition protocols based on patient body mass index (BMI) and the injected dose per kilogram for 68Ga-DOTA-NOC PET/CT imaging. Patients and Methods: This was a retrospective analysis of 51 patients (21 males and 30 females) who underwent clinical 68Ga-DOTANOC PET/CT imaging from November 2016 to March 2018 in Nanjing first hospital, the average BMI of these patients was 23.18 ± 3.45 kg/m2 with injected dose of 39.55–110.11 MBq. The study population was classified into groups based on Chinese standard BMI and injected dose. PET image quality and acquisition time were evaluated by coefficient of variance (CV) in the liver slice. Results: (1) The CV significantly increased with increasing weight and BMI (r = 0.647, 0.483, all P < 0.01), and significantly decreased with increasing injected dose per kilogram (r = 0 695, P < 0.01). (2) The CV differed significantly among 4 BMI-based groups, except for normal-weight group versus overweight group and overweight group versus obese group (P < 0.01), and the ratio of overweight group and obese group to normal weight group was approximately 1.1 and 1.2, respectively. Meanwhile, the CV had a significant statistical difference among 3 injected dose per kilogram groups (P < 0.01), and the ratio of that for low dose group and high dose group to moderate dose group was approximately 1.2 and 0.8. Conclusion: The findings showed a feasibility of obtaining consistently high-quality PET image at low injected dose and shorter acquisition time. Estimation of optimal acquisition time and injected dose using CV is valid in improving PET image quality, which can provide reference for the establishment and promotion of 68Ga-DOTA-NOC imaging protocols in China.

scholarly journals Impacts of acquisition and reconstruction parameters on the absolute technetium quantification of the cadmium–zinc–telluride-based SPECT/CT system: a phantom study

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ruyi Zhang ◽  
Miao Wang ◽  
Yaqian Zhou ◽  
Shen Wang ◽  
Yiming Shen ◽  
...  
Keyword(s):  
Image Quality ◽  
Cadmium Zinc Telluride ◽  
Scatter Correction ◽  
Zinc Telluride ◽  
Acquisition Time ◽  
Energy Window ◽  
Image Correction ◽  
Recovery Coefficient ◽  
Czt Spect ◽  
Cadmium Zinc

Abstract Background The digital cadmium–zinc–telluride (CZT)-based SPECT system has many advantages, including better spatial and energy resolution. However, the impacts of different acquisition and reconstruction parameters on CZT SPECT quantification might still need to be validated. This study aimed to evaluate the impacts of acquisition parameters (the main energy window and acquisition time per frame) and reconstruction parameters (the number of iterations, subsets in iterative reconstruction, post-filter, and image correction methods) on the technetium quantification of CZT SPECT/CT. Methods A phantom (PET NEMA/IEC image quality, USA) was filled with four target-to-background (T/B) ratios (32:1, 16:1, 8:1, and 4:1) of technetium. Mean uptake values (the calculated mean concentrations for spheres) were measured to evaluate the recovery coefficient (RC) changes under different acquisition and reconstruction parameters. The corresponding standard deviations of mean uptake values were also measured to evaluate the quantification error. Image quality was evaluated using the National Electrical Manufacturers Association (NEMA) NU 2–2012 standard. Results For all T/B ratios, significant correlations were found between iterations and RCs (r = 0.62–0.96 for 1–35 iterations, r = 0.94–0.99 for 35–90 iterations) as well as between the full width at half maximum (FWHM) of the Gaussian filter and RCs (r = − 0.86 to − 1.00, all P values < 0.05). The regression coefficients of 1–35 iterations were higher than those of 35–90 iterations (0.51–1.60 vs. 0.02–0.19). RCs calculated with AC (attenuation correction) + SC (scatter correction) + RR (resolution recovery correction) combination were more accurate (53.82–106.70%) than those calculated with other combinations (all P values < 0.05). No significant statistical differences (all P values > 0.05) were found between the 15% and 20% energy windows except for the 32:1 T/B ratio (P value = 0.023) or between the 10 s/frame and 120 s/frame acquisition times except for the 4:1 T/B ratio (P value = 0.015) in terms of RCs. Conclusions CZT-SPECT/CT of technetium resulted in good quantification accuracy. The favourable acquisition parameters might be a 15% energy window and 40 s/frame of acquisition time. The favourable reconstruction parameters might be 35 iterations, 20 subsets, the AC + SC + RR correction combination, and no filter.

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