Comparison of VRX CT scanners geometries

DiBianca, Frank A.; Melnyk, Roman; Duckworth, Christopher N.; Russ, Stephan; Jordan, Lawrence M.; Laughter, Joseph S.

doi:10.1117/12.430890

Cited by 7 publications

(13 citation statements)

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“…6 An analytical and Monte Carlo study of this 576channel detector has demonstrated several advantages of the dual-arm detector configuration compared with the singlearm configuration. 7 Therefore, the 576-channel dual-arm detector has been used to construct an experimental VRX CT scanner. Initial assessment of the scanner has included a Monte Carlo study of the x-ray cross-talk and has indicated the need for antiscatter collimation and optimization of the x-ray tube voltage.…”

Section: Introductionmentioning

confidence: 99%

Modeling and measurement of the detector presampling MTF of a variable resolution x‐ray CT scanner

Melnyk

DiBianca

2007

Medical Physics

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The detector presampling MTF of a 576-channel variable resolution x-ray (VRX) CT scanner was evaluated in this study. The scanner employs a VRX detector, which provides increased spatial resolution by matching the scanner's field of view (FOV) to the size of an object being imaged. Because spatial resolution is the parameter the scanner promises to improve, the evaluation of this resolution is important. The scanner's pre-reconstruction spatial resolution, represented by the detector presampling MTF, was evaluated using both modeling (Monte Carlo simulation) and measurement (the moving slit method). The theoretical results show the increase in the cutoff frequency of the detector presampling MTF from 1.39 cy/mm to 43.38 cy/mm as the FOV of the VRX CT scanner decreases from 32 cm to 1 cm. The experimental results are in reasonable agreement with the theoretical data. Some discrepancies between the measured and the modeled detector presampling MTFs can be explained by the limitations of the model. At small FOVs (1-8 cm), the MTF measurements were limited by the size of the focal spot. The obtained results are important for further development of the VRX CT scanner.

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Section: Introductionmentioning

confidence: 99%

Modeling and measurement of the detector presampling MTF of a variable resolution x‐ray CT scanner

Melnyk

DiBianca

2007

Medical Physics

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“…Among the various VRX detector models, the dual-arm geometry is preferable because of its left-right symmetry, low magnification nonuniformity from one end of the detector to the other, and compact system design. 20 A schematic diagram of the proposed oriented cell detector design is depicted in Fig. 1͑b͒.…”

Section: Introductionmentioning

confidence: 99%

Novel detector design for reducing intercell x‐ray cross‐talk in the variable resolution x‐ray CT scanner: A Monte Carlo study

Arabi

Kamali-Asl

et al. 2011

Medical Physics

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Purpose:The variable resolution x-ray ͑VRX͒ CT scanner provides substantial improvement in the spatial resolution by matching the scanner's field of view ͑FOV͒ to the size of the object being imaged. Intercell x-ray cross-talk is one of the most important factors limiting the spatial resolution of the VRX detector. In this work, a new cell arrangement in the VRX detector is suggested to decrease the intercell x-ray cross-talk. The idea is to orient the detector cells toward the opening end of the detector. Methods: Monte Carlo simulations were used for performance assessment of the oriented cell detector design. Previously published design parameters and simulation results of x-ray cross-talk for the VRX detector were used for model validation using the GATE Monte Carlo package. In the first step, the intercell x-ray cross-talk of the actual VRX detector model was calculated as a function of the FOV. The obtained results indicated an optimum cell orientation angle of 28°to minimize the x-ray cross-talk in the VRX detector. Thereafter, the intercell x-ray cross-talk in the oriented cell detector was modeled and quantified. Results:The intercell x-ray cross-talk in the actual detector model was considerably high, reaching up to 12% at FOVs from 24 to 38 cm. The x-ray cross-talk in the oriented cell detector was less than 5% for all possible FOVs, except 40 cm ͑maximum FOV͒. The oriented cell detector could provide considerable decrease in the intercell x-ray cross-talk for the VRX detector, thus leading to significant improvement in the spatial resolution and reduction in the spatial resolution nonuniformity across the detector length. Conclusions: The proposed oriented cell detector is the first dedicated detector design for the VRX CT scanners. Application of this concept to multislice and flat-panel VRX detectors would also result in higher spatial resolution.

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“…The symmetry of this configuration helps reduce the inconveniences produced by the fact that in a single-arm system the cells at their "closer" side of the arm appear bigger than those in the "far" side, a fact that becomes more apparent in systems with a wide fan beam, i.e., those in which the distance from the focal spot to the detector is not much larger than the length of the arm. In a symmetrical two-arm configuration, both arms provided the same increase in spatial resolution [14,15,51].…”

Section: Single and Dual Arm Vrxmentioning

confidence: 99%

“…By combining the information from the two arms, we will find that while we can image relatively large objects (up to the size of the FOV determined by the arm with the larger angle) a circular region around the center of the image will be reconstructed at a higher resolution that can only be achieved in a single arm or a symmetrical dual arm configuration by sacrificing part of the field of view. A system with this property is called a targeting VRX scanner, the interior, higher resolution region is called the target region, and the rest of the FOV is called the external region [13,15,51,23].…”

Section: Two and Four Arm Vrx In Targeting Modementioning

confidence: 99%

“…The arms will be located symmetrically, with the two "inner" arms tilted to a small angle while the two "outer" arms are placed at the ends of the inner arms, at a larger angle relative to the system centerline. The inner arms provide the increased spatial resolution of the target region, while the outer arms provided the large field of view [13,15,51,23]. …”

Section: Two and Four Arm Vrx In Targeting Modementioning

confidence: 99%

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Development and Application of Computational Tools for the Study and Optimization of Variable Resolution X-ray (VRX) Computed Tomography Scanners

Rendon¹

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Comparison of VRX CT scanners geometries

Cited by 7 publications

References 0 publications

Modeling and measurement of the detector presampling MTF of a variable resolution x‐ray CT scanner

Modeling and measurement of the detector presampling MTF of a variable resolution x‐ray CT scanner

Novel detector design for reducing intercell x‐ray cross‐talk in the variable resolution x‐ray CT scanner: A Monte Carlo study

Development and Application of Computational Tools for the Study and Optimization of Variable Resolution X-ray (VRX) Computed Tomography Scanners

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