Interesting detector shapes for third generation CT scanners

Kachelrieß, Marc

doi:10.1118/1.4789588

Cited by 7 publications

(6 citation statements)

References 30 publications

(16 reference statements)

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“…A recent study suggests that this geometry requires a small detector area and only a few detector pixels for third-generation CT systems [46]. A Katsevich-type algorithm for native ring detector geometry was developed in this study.…”

Section: Discussionmentioning

confidence: 99%

A stationary computed tomography system with cylindrically distributed sources and detectors

Chen

Zhao

2014

Journal of X-Ray Science and Technology

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BACKGROUND: The temporal resolution of current computed tomography (CT) systems is limited by the rotation speed of their gantries. OBJECTIVE: A helical interlaced source detector array (HISDA) CT, which is a stationary CT system with distributed X-ray sources and detectors, is presented in this paper to overcome the aforementioned limitation and achieve high temporal resolution. METHODS: Projection data can be obtained from different angles in a short time and do not require source, detector, or object motion. Axial coverage speed is increased further by employing a parallel scan scheme. Interpolation is employed to approximate the missing data in the gaps, and then a Katsevich-type reconstruction algorithm is applied to enable an approximate reconstruction. RESULTS: The proposed algorithm suppressed the cone beam and gap-induced artifacts in HISDA CT. The results also suggest that gap-induced artifacts can be reduced by employing a large helical pitch for a fixed gap height. CONCLUSIONS: HISDA CT is a promising 3D dynamic imaging architecture given its good temporal resolution and stationary advantage. Y. Chen et al. / A stationary computed tomography system with cylindrically distributed sources and detectorsspeed because an ultra-fast gantry rotation speed creates a strong centrifugal force that may exceed mechanical limits. The shortest rotation time of a typical 320-row multi-slice CT (Aquilion ONE, Toshiba Medical Systems Corporation, Japan) is 0.35 s [1]. Motion organs, such as the heart and the lungs, reduce image quality because of insufficient temporal resolution. Insufficient temporal resolution causes deformation in structure, and it requires additional correction to estimate the real length of the object [2]. A moving X-ray source also enlarges the size of the X-ray focal spots along the motion direction, thereby resulting in image blurring. The third generation CT also requires geometric calibration [3].New CT architectures are being developed to obtain improved temporal resolution. These architectures are divided into rotational and stationary classes. Some technologies in the rotational class improve temporal performance. The multi-slice CT can increase the longitudinal volume coverage [4]. Dualsource technologies [5] have also been used in cardiac CT [6,7], whereas triple-source CT [8-10] is theoretically capable of increasing the temporal resolution by up to three times. Because gantry rotation speed remains a bottleneck in these systems, there is no much space for further improving the temporal resolution.The stationary class has a long history. One example of this class is electron beam CT (EBCT) [11,12] which is proposed in 1979 and uses an X-ray tube with a ring-shaped anode instead of the conventional, rotational X-ray tube. X-rays are generated by electromagnetically steering the electron beam to different spots on the ring-shaped anode. Scanning is thus controlled by electromagnetic rather than mechanical rotation. This change can reduce the scanning time for one circle to 50 ms [13]. El...

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Section: Discussionmentioning

confidence: 99%

A stationary computed tomography system with cylindrically distributed sources and detectors

Chen

Zhao

2014

Journal of X-Ray Science and Technology

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“…56,67,78,104 However, the MSUs and the low-field scanners need calibrations and correction for drifts. 81,[101][102][103][104][105][106][107][108][109] The fixed scanners are typically not compact 103 and hence demand supporting infrastructure and logistics, resulting in a bigger footprint. Fixed-MR scanners require significantly higher electrical power compared to the low-field scanners.…”

Section: Potential Of Low-field Mri For Stroke Imagingmentioning

confidence: 99%

Low‐Field MRI of Stroke: Challenges and Opportunities

Bhat

Fernandes

Poojar

et al. 2020

Magnetic Resonance Imaging

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Stroke is a leading cause of death and disability worldwide. The reasons for increased stroke burden in developing countries are inadequately controlled risk factors resulting from poor public awareness and inadequate infrastructure. Computed tomography and MRI are common neuroimaging modalities used to assess stroke with diffusion-weighted MRI, in particular, being the recommended choice for acute stroke imaging. However, access to these imaging modalities is primarily restricted to major cities and high-income groups. In the case of stroke, the time-window of treatment to limit the damage is of a few hours and needs a point-of-care diagnosis. A low-cost MR system typically achieved at the ultra-lowand very-low-field would meet the need for a geographically accessible and portable solution. We review studies focused on accessible stroke imaging and recent developments in MR methodologies, including hardware, to image at low fields. We hypothesize that in the absence of a formal, rapid stroke triaging system, the value of timely on-site delivery of the scanner to the stroke patient can be significant. To this end, we discuss multiple recent hardware and methods developments in the low-field regime. Our review suggests a compelling need to explore further the trade-offs between high signal, contrast, and accessibility at low fields in low-income communities.

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“…While we covered a wide range of CT architectures, this study is not exhaustive. For instance, concepts were proposed with alternate detector designs [41,42] or with source and detector rotating in opposite directions [43,44].…”

Section: Semi-stationary Architectures-mentioning

confidence: 99%