Image quality assessment along the one metre axial field-of-view of the total-body Biograph Vision Quadra PET/CT system for 18F-FDG

Rausch, Ivo; Mannheim, Julia G.; Kupferschläger, Jürgen; Fougère, Christian la; Schmidt, F.

doi:10.1186/s40658-022-00516-5

Cited by 20 publications

(18 citation statements)

References 32 publications

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“…This study differs from the recently published study by Rausch et al [ 18 ] as it further investigates the CRCs and voxel noise at multiple positions within the FOV with both axial and transaxial offsets for multiple isotopes (F-18, Zr-89 and Ga-68), different acceptance angles and number of iterations for image reconstruction, whereas Rausch et al investigated the CRCs at four axial positions focusing on F-18 for the standard clinical reconstruction protocol using an Ordinary Poisson ordered subsets expectation maximization (OP-OSEM) algorithm with four iterations and an acceptance angle of 18° [ 18 ]. Hence, our study provides additional data to fully characterize the entire FOV of the Biograph Vision Quadra in regards to CRCs and voxel noise.…”

Section: Introductioncontrasting

confidence: 99%

“…The CRC values of the 37 and 28 mm spheres in the cFOV are comparable with reported data from the same scanner [ 7 , 18 ], demonstrating similar system performance to other systems from the same vendor. Minor differences in CRC values may result due to VOI positioning, utilized software for analysis [ 19 ], as well as calculation of recovery (based on NEMA, etc.).…”

Section: Discussionsupporting

confidence: 80%

“…In general, comparisons of the CRC values along the axial FOV to the literature values are limited, as the NEMA protocol requires the phantom only to be centered in the FOV. Rausch et al [ 18 ] recently investigated the CRCs for the Biograph Vision Quadra at four positions along the axial FOV (cFOV, axial offsets of 250 mm, 450 mm and 505 mm) and determined a stable behavior for the spheres larger than 13 mm and axial offsets up to 450 mm (for acquisition times of 120 and 600 s). This is consistent with our data reporting that for the 37 and 28 mm spheres the CRCs were stable along the axial FOV (see Fig.…”

Section: Discussionmentioning

confidence: 99%

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Characterization of the partial volume effect along the axial field-of-view of the Biograph Vision Quadra total-body PET/CT system for multiple isotopes

Mannheim

Rausch

Conti³

et al. 2023

EJNMMI Phys

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Background Total-body PET scanners with axial field of views (FOVs) longer than 1 m enable new applications to study multiple organs (e.g., the brain-gut-axis) simultaneously. As the spatial resolution and the associated partial volume effect (PVE) can vary significantly along the FOV, detailed knowledge of the contrast recovery coefficients (CRCs) is a prerequisite for image analysis and interpretation of quantitative results. The aim of this study was to determine the CRCs, as well as voxel noise, for multiple isotopes throughout the 1.06 m axial FOV of the Biograph Vision Quadra PET/CT system (Siemens Healthineers). Materials and Methods Cylindrical phantoms equipped with three different sphere sizes (inner diameters 7.86 mm, 28 and 37 mm) were utilized for the PVE evaluation. The 7.86 mm sphere was filled with F-18 (8:1 and 4:1), Ga-68 (8:1) and Zr-89 (8:1). The 28 mm and 37 mm spheres were filled with F-18 (8:1). Background concentration in the respective phantoms was of ~ 3 kBq/ml. The phantoms were measured at multiple positions in the FOV (axial: 0, 10, 20, 30, 40 and 50 cm, transaxial: 0, 10, 20 cm). The data were reconstructed with the standard clinical protocol, including PSF correction and TOF information with up to 10 iterations for maximum ring differences (MRDs) of 85 and 322; CRCs, as well as voxel noise levels, were determined for each position. Results F-18 CRCs (SBR 8:1 and 4:1) of the 7.86 mm sphere decreased up to 18% from the center FOV (cFOV) toward the transaxial edge and increased up to 17% toward the axial edge. Noise levels were below 15% for the default clinical reconstruction parameters. The larger spheres exhibited a similar pattern. Zr-89 revealed ~ 10% lower CRCs than F-18 but larger noise (9.1% (F-18), 19.1% (Zr-89); iteration 4, cFOV) for the default reconstruction. Zr-89 noise levels in the cFOV significantly decreased (~ 28%) when reconstructing the data with MRD322 compared with MRD85 along with a slight decrease in CRC values. Ga-68 exhibited the lowest CRCs for the three isotopes and noise characteristics comparable to those of F-18. Conclusions Distinct differences in the PVE within the FOV were detected for clinically relevant isotopes F-18, Ga-68 and Zr-89, as well as for different sphere sizes. Depending on the positions inside the FOV, the sphere-to-background ratios, count statistics and isotope used, this can result in an up to 50% difference between CRCs. Hence, these changes in PVE can significantly affect the quantitative analysis of patient data. MRD322 resulted in slightly lower CRC values, especially in the center FOV, whereas the voxel noise significantly decreased compared with MRD85.

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Section: Introductioncontrasting

confidence: 99%

Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

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Characterization of the partial volume effect along the axial field-of-view of the Biograph Vision Quadra total-body PET/CT system for multiple isotopes

Mannheim

Rausch

Conti³

et al. 2023

EJNMMI Phys

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“…The NEMA NU2 CRC measurements performed on state-of-the-art commercial PET scanners (Jakoby et al 2011, Rausch et al 2015, 2019, van Sluis et al 2019, Prenosil et al 2022, Rausch et al 2022 show a general trend towards an increased CRC with increasing sphere size and decreasing voxel size. However, there are prominent deviations in the experimental results, examples of which are shown in figure 1 in a comparison of the NEMA NU 2-2018 CRC measurements performed on four different PET/CT scanners, all using different implementations of the TOF-OSEM image reconstruction algorithm with RM.…”

Section: Introductionmentioning

confidence: 96%

Numerical investigation reveals challenges in measuring the contrast recovery coefficients in PET

Bayerlein,

Spencer,

Abdelhafez

et al. 2023

Phys. Med. Biol.

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Objective. Contrast recovery coefficient (CRC) is essential for image quality (IQ) assessment in positron emission tomography (PET), typically measured according to the NEMA NU 2 standard. This study quantifies systematic uncertainties of the CRC measurement by a numerical investigation of the effects from scanner-independent parameters like voxel size, region-of-interest (ROI) misplacement, and sphere position on the underlying image grid. Approach. CRC measurements with 2D and 3D ROIs were performed on computer-generated images of a NEMA IQ-like phantom, using voxel sizes of 1‒4 mm for sphere diameters of 5‒40 mm – first in absence of noise and blurring, then with simulated spatial resolution and image noise with varying noise levels. The systematic uncertainties of the CRC measurement were quantified from above variations of scanner-independent parameters. Subsampled experimental images of a NEMA IQ phantom were additionally used to investigate the impact of ROI misplacement at different noise levels. Main results. In absence of noise and blurring, systematic uncertainties were up to 28.8% and 31.0% with 2D and 3D ROIs, respectively, for the 10-mm sphere, with the highest impact from ROI misplacement. In all cases, smaller spheres showed higher uncertainties with larger voxels. Contrary to prior assumptions, the use of 3D ROIs did not exhibit less susceptibility for parameter changes. Experimental and computer-generated images both demonstrated considerable variations on individual CRC measurements when background coefficient-of-variation exceeded 20%, despite negligible effects on mean CRC. Significance. This study underscores the effect of scanner-independent parameters on reliability, reproducibility, and comparability of CRC measurements. Our findings highlight the trade-off between the benefits of smaller voxel sizes and noise-induced CRC fluctuations, which is not considered in the current version of the NEMA IQ standards. The results furthermore warrant adjustments to the standard to accommodate the advances in sensitivity and spatial resolution of current-generation PET scanners.

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“…The idea is to have detector coverage over the whole torso (about 1 m axial length, e.g. the Biograph Vision Quadra [5,6]) or even the 'total body' (about 2 m axial length, e.g. the uExplorer [3,7]).…”

Section: Introductionmentioning

confidence: 99%

System characteristics comparison of the Walk-Through Total-Body PET and the Biograph Vision Quadra PET/CT

Dadgar

Maebe

Akl

et al. 2023

Preprint

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Background: Although a new generation of tomographs with a larger axial field of view called total-body PET has been developed, they are not widely utilized due to their high cost compared to conventional scanners. The walk-through total-body PET scanner is introduced as a high-throughput and cost-efficient alternative to total-body PET scanners, by making use of a flat-panel geometry and lower cost, depth-of-interaction capable, monolithic BGO detectors. The main aim of the presented study is to evaluate the system characteristics of the walk-through total-body PET scanner by comparing it with the Siemens Biograph Vision Quadra total-body PET. Methods: The walk-through total-body PET is comprised of two flat detector panels, spaced 50 cm apart. Each panel, 70 x 106 cm^2 in size, consists of 280 BGO-based monolithic detectors. The Biograph Vision Quadra, one of the most common total-body PET scanners with 106 cm of axial field-of-view, is constructed with pixelated LSO scintillation crystals. The spatial resolution, sensitivity, count rate performance, scatter fractions and image quality of both scanners are simulated in the GATE simulation toolkit for comparison. Results: Due to the DOI-capable detectors used in the walk-through total-body PET, the spatial resolution of this scanner was below 2 mm in the entire volume of the tomograph. This resolution is a large improvement compared to the values of the Quadra. This feature allows the walk-through total-body PET to use its maximum sensitivity (∼ 26%) for data acquisition and image reconstruction. While the Biograph Vision Quadra has a higher primary sensitivity (∼ 31.5%), after applying an 85 maximum ring difference cut to limit axial resolution loss, the corresponding value dropped by a factor of three (∼ 11.2%). Conclusion: Based on the excellent combination of very good spatial resolution and high sensitivity of the walk-through total-body PET, along with a 2.2 times lower scintillation crystal volume and 1.8 times lower SiPM surface, this scanner can be a very cost-efficient alternative for total-body PET scanners.

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Image quality assessment along the one metre axial field-of-view of the total-body Biograph Vision Quadra PET/CT system for 18F-FDG

Cited by 20 publications

References 32 publications

Characterization of the partial volume effect along the axial field-of-view of the Biograph Vision Quadra total-body PET/CT system for multiple isotopes

Characterization of the partial volume effect along the axial field-of-view of the Biograph Vision Quadra total-body PET/CT system for multiple isotopes

Numerical investigation reveals challenges in measuring the contrast recovery coefficients in PET

System characteristics comparison of the Walk-Through Total-Body PET and the Biograph Vision Quadra PET/CT

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