Four-arm variable-resolution x-ray detector for CT target imaging

DiBianca, Frank A.; Gulabani, Daya; Jordan, Lawrence M.; Vangala, Sravanthi; Rendon, David A.; Laughter, Joseph S.; Melnyk, Roman; Gaber, M. Waleed; Keyes, G.

doi:10.1117/12.594102

Cited by 7 publications

(16 citation statements)

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“…Nevertheless, in practice the difference in resolution in different regions of the image is not very significant. On the other hand, if the arms of a two-arm VRX system are placed asymmetrically around the main (F s C r ) axis, or if a symmetrical four-arm system with the inner arms located at smaller half-opening angles is used, the central region of the image (called the target zone) will have a considerably higher spatial resolution, while the system maintains a relatively large field of view [13]. show schematic representations of a four-arm targeting system, as well as two different two-arm targeting configurations.…”

Section: Targeting Vrx Scannersmentioning

confidence: 99%

“…For example, the detectors in a four-arm system can be coupled to form a two-or even a single-arm system, and in multi-arm systems the arms can be placed in different positions to allow for target imaging. In target imaging, a region at the center of the image, known as the target zone, is imaged at a higher resolution while the external field of view remains large [13]. Target imaging with multi-arm VRX scanners is discussed in Section 3.1.3.…”

Section: Comparison Of Different Vrx Ct Implementations and Configuramentioning

confidence: 99%

“…When the four-arm VRX configuration was introduced [13], it became apparent that rather than practically rewriting the code to produce yet another inflexible set of algorithms, our efforts should be centered on developing comprehensive and flexible algorithms that would easily accommodate all existing and future VRX models (or at least all single-slice ones) regardless of their configuration and the specifications of the parts used. In the remainder of this Chapter we will describe the main "universal" VRX algorithms related to the accurate reconstruction of images acquired with singleslice VRX scanners regardless of the number of arms and their specifications.…”

Section: Development Of Reconstruction Algorithmsmentioning

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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Section: Targeting Vrx Scannersmentioning

confidence: 99%

Section: Comparison Of Different Vrx Ct Implementations and Configuramentioning

confidence: 99%

Section: Development Of Reconstruction Algorithmsmentioning

confidence: 99%

Section: Two and Four Arm Vrx In Targeting Modementioning

confidence: 99%

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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Computational models of Variable Resolution (VRX) CT scanners

Rendon

DiBianca

Keyes

2009

2009 First Annual ORNL Biomedical Science &Amp; Engineering Conference

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Variable Resolution X-ray (VRX) CT scanners allow imaging of different sized anatomy at the same proportional level of detail using the same device. For example, the same scanner can be used to image large animals such as dogs, and small ones, like mice, with the same level of anatomical detail. This is achieved by tilting the x-ray detectors so that the projected size of the detecting elements is varied producing reconstructions of smaller fields of view with higher spatial resolution [1], [2]. The resolution of central region of a relatively large field of view can be further enhanced by using two or more detectors with different degrees of tilting [3], [4]. Scanners with such "target" regions are useful for following the evolution of pre-diagnosed lesions or any other situation in which a high resolution is indispensable only for a small region of the patient's anatomy, but a larger field of view is needed to avoid artifacts. A computational model of multi-arm VRX scanners was developed as a fundamental aid in the study and development of these devices [4], [5].This work studies the effect of varying several parameters of the computational model on the quality of the reconstructed image. This will affect the usefulness of the simulator in predicting the quality of the images produced by the scanner being modeled. The parameters studied include the number of X-ray beams per detector cell, the number of energy bins in which the incoming polychromatic beam is divided, and the number of views used in the reconstruction. All these parameters will affect the performance of the simulator both in terms of the time required to perform the computations, and the accuracy of the resulting image. The ideal combination of parameters will allow for faster computation without compromising significantly the resulting quality.

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Performance analysis of a CsI-based flat panel detector in a cone beam variable resolution x-ray system

et al. 2007

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A new Cone-Beam CT (CBCT) system is introduced that uses the concept of Variable Resolution X-ray (VRX) detection, which has previously been demonstrated to significantly increase spatial resolution for small objects. An amorphous silicon Flat Panel Detector (FPD) with a CsI scintillator (PaxScan 2020, Varian, Salt Lake City, UT) is coupled with a micro-focus x-ray tube (35 -80 kVp, 10 -250 µA) to form a CBCT. The FPD is installed on a rotating arm that can be adjusted to any angle θ, called the VRX angle, between 90 o and 0 o with respect to the x-ray direction. A VRX angle of 90 o for the detector corresponds to a conventional CBCT whereas a VRX angle of 30 o means that the detector is tilted 90 o -30 o = 60 o from its perpendicular position. Tilting the FPD in this manner reduces both the line-spread function width and the sampling distance by a factor of sin(θ), thereby increasing detector spatial resolution proportionately. An in-house phantom is used to measure the MTF of the reconstructed CT images using different VRX angles. An increase by a factor of 1.67 ± 0.007 is observed in the MTF cutoff frequency at 30 o compared to 90 o in images acquired at 75 kVp. Expected theoretical value for this case is 2.0. The new Cone-Beam Variable Resolution X-ray (CB-VRX) CT system is expected to significantly improve the images acquired from small objects -such as small animals -while exploiting the opportunities offered by a conventional CBCT.

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Four-arm variable-resolution x-ray detector for CT target imaging

Cited by 7 publications

References 0 publications

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

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

Computational models of Variable Resolution (VRX) CT scanners

Performance analysis of a CsI-based flat panel detector in a cone beam variable resolution x-ray system

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