Two-dimensional anti-scatter grids for computed tomography detectors

Vogtmeier, Gereon; Dorscheid, R.; Engel, Klaus; Luhta, Randy P.; Mattson, Rod; Harwood, Brian; Appleby, Michael C.; Randolph, Bill; Klinger, Jill

doi:10.1117/12.770063

Cited by 28 publications

(33 citation statements)

References 16 publications

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“…Noise reduction can be accomplished by the use of a post-patient, detector-mounted, two-dimensional anti-scatter grid (2D ASG). Such a 2D ASG reduces scatter by a factor of three [40,41] compared to a traditional one-dimensional ASG. This improvement in scatterto-primary ratio (SPR) increases CT number homogeneity in the bariatric thorax and facilitates an increase in low contrast resolution for soft tissue imaging [40,41], which is particularly important for characterizing non-calcified plaque and regions of reduced myocardial perfusion in all patients.…”

Section: X-ray Tube Powermentioning

confidence: 95%

“…Such a 2D ASG reduces scatter by a factor of three [40,41] compared to a traditional one-dimensional ASG. This improvement in scatterto-primary ratio (SPR) increases CT number homogeneity in the bariatric thorax and facilitates an increase in low contrast resolution for soft tissue imaging [40,41], which is particularly important for characterizing non-calcified plaque and regions of reduced myocardial perfusion in all patients. In addition to providing the X-ray tube power necessary to image obese patients, increased tube current-time products (mAs) are possible at reduced tube voltages (e.g., 80 kVp) such that diagnostic image quality at substantially reduced effective radiation dose is possible in small-and medium-sized patients [24].…”

Section: X-ray Tube Powermentioning

confidence: 95%

“…The ability to image obese and bariatric patients with BMI greater than 30 kg/m 2 using prospective CCTA requires higher X-ray tube power (e.g., 120 kW) and noise-reduction measures [40,41]. A 120 kW system provides the necessary instantaneous tube power to support 0.27 s rotation times in a prospective acquisition mode.…”

Section: X-ray Tube Powermentioning

confidence: 99%

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Low-dose prospectively gated 256-slice coronary computed tomographic angiography

Weigold

Olszewski

Walker

2009

Int J Cardiovasc Imaging

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Since the introduction of 64-slice scanners, multidetector computed tomography (MDCT) has experienced a marked increase in adoption for the noninvasive assessment of coronary artery disease, although radiation dose concerns remain. The recent introduction of prospective coronary CT angiography (CCTA) has begun to address these concerns; however, its applicability with existing scanners remains limited to cohorts defined by heart rate, heart rate variability, and body mass index. This paper reviews prospective CCTA, the effect of heart rate and heart rate variability on image quality, and the physiologic basis for selection of optimal prospective imaging windows. We then discuss 256-slice technology and our first 4 months of clinical experience with 256-slice prospective CCTA. Our early clinical results indicate that high-quality, low-dose prospective coronary CTA may be applied to patients with higher heart rates, higher BMI, and with less sensitivity to heart rate variability using 256-slice MDCT.

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Section: X-ray Tube Powermentioning

confidence: 95%

Section: X-ray Tube Powermentioning

confidence: 95%

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Low-dose prospectively gated 256-slice coronary computed tomographic angiography

Weigold

Olszewski

Walker

2009

Int J Cardiovasc Imaging

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“…Scatter grids are parallel (one-dimensional) or crossed lamellas (two-dimensional) positioned between the individual detectors to absorb the scattered photons. X-ray absorbing materials like tungsten, lead, copper, molybdenum and tantalum can be used for scatter grids [9].…”

Section: Device Equipmentmentioning

confidence: 99%

“…These post-processing techniques are computationally intensive but the processing time takes less than 1 minute. Care has to be taken, however, to identify new artifacts induced by these projection-based algorithms, especially areas of pseudo-osteolysis that commonly appear at the bone-metal interface [9,16]. The radiologist can avoid making the false-positive diagnosis of implant loosening or an osteolytic bone lesion only by comparing the projection-based corrected images side-by-side with the standard CT reconstructions (▶ Fig.…”

Section: Post-processingmentioning

confidence: 99%

CT and MRI Techniques for Imaging Around Orthopedic Hardware

Duong

Sutter

Skornitzke

et al. 2017

Fortschr Röntgenstr

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ZUSAMMENFASSUNGOrthopädische Implantate verringern die Bildqualität in der Schnittbildgebung. Bei steigendem Einsatz von orthopädi-schen Implantaten in einer alternden Bevölkerung ist eine Metallartefaktreduktion von zunehmender Bedeutung. Im folgenden Review möchten wir einen Überblick über die wesentlichen Artefakte in der Computertomografie und Magnetresonanztomografie sowie die neuesten Standards zur Verbesserung der Bildqualität geben. Alle Schritte der Bildakquisition von Gerätewahl über Scanvorbereitungen und -parameter bis hin zur Bildverarbeitung beeinflussen das Ausmaß der Metallartefakte. Technische Fortschritte wie die Dual-energy-Computertomografie mit der Option der Virtuellen monochromatischen Bildgebung sowie neue Implantatmaterialien bieten weitere Möglichkeiten der Metallartefaktreduktion in CT und MRT. Dezidierte MetallartefaktSequenzen beinhalten Algorithmen zur Artefaktreduktion und zur Verbesserung der Bildqualität des umgebenden Gewebes und sind essenzielle Werkzeuge in der orthopä-dischen Bildgebung zur frühzeitigen Detektion von postoperativen Komplikationen. ABSTR AC TOrthopedic hardware impairs image quality in cross-sectional imaging. With an increasing number of orthopedic implants in an aging population, the need to mitigate metal artifacts in computed tomography and magnetic resonance imaging is becoming increasingly relevant. This review provides an overview of the major artifacts in CT and MRI and state-ofthe-art solutions to improve image quality. All steps of image acquisition from device selection, scan preparations and parameters to image post-processing influence the magnitude of metal artifacts. Technological advances like dual-energy CT with the possibility of virtual monochromatic imaging (VMI) and new materials offer opportunities to further reduce artifacts in CT and MRI. Dedicated metal artifact reduction sequences contain algorithms to reduce artifacts and improve imaging of surrounding tissue and are essential tools in orthopedic imaging to detect postoperative complications in early stages.

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Impact of scatter radiation on spectral quantification performance of first‐ and second‐generation dual‐layer spectral computed tomography

Salazar,

Liu,

Perkins

et al. 2024

J Applied Clin Med Phys

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ObjectiveTo assess the impact of scatter radiation on quantitative performance of first and second‐generation dual‐layer spectral computed tomography (DLCT) systems.MethodA phantom with two iodine inserts (1 and 2 mg/mL) configured to intentionally introduce high scattering conditions was scanned with a first‐ and second‐generation DLCT. Collimation widths (maximum of 4 cm for first generation and 8 cm for second generation) and radiation dose levels were varied. To evaluate the performance of both systems, the mean CT numbers of virtual monoenergetic images (MonoEs) at different energies were calculated and compared to expected values. MonoEs at 50 versus 150 keV were plotted to assess material characterization of both DLCTs. Additionally, iodine concentrations were determined, plotted, and compared against expected values. For each experimental scenario, absolute errors were reported.ResultsAn experimental setup, including a phantom design, was successfully implemented to simulate high scatter radiation imaging conditions. Both CT scanners illustrated high spectral accuracy for small collimation widths (1 and 2 cm). With increased collimation (4 cm), the second‐generation DLCT outperformed the earlier DLCT system. Further, the spectral performance of the second‐generation DLCT at an 8 cm collimation width was comparable to a 4 cm collimation on the first‐generation DLCT. A comparison of the absolute errors between both systems at lower energy MonoEs illustrates that, for the same acquisition parameters, the second‐generation DLCT generated results with decreased errors. Similarly, the maximum error in iodine quantification was less with second‐generation DLCT (0.45 and 0.33 mg/mL for the first and second‐generation DLCT, respectively).ConclusionThe implementation of a two‐dimensional anti‐scatter grid in the second‐generation DLCT improves the spectral quantification performance. In the clinical routine, this improvement may enable additional clinical benefits, for example, in lung imaging.

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Two-dimensional anti-scatter grids for computed tomography detectors

Cited by 28 publications

References 16 publications

Low-dose prospectively gated 256-slice coronary computed tomographic angiography

Low-dose prospectively gated 256-slice coronary computed tomographic angiography

CT and MRI Techniques for Imaging Around Orthopedic Hardware

Impact of scatter radiation on spectral quantification performance of first‐ and second‐generation dual‐layer spectral computed tomography

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