Comparison of vessel contrast measured with a scanning-beam digital x-ray system and an image intensifier/television system

Speidel, Michael A.; Wilfley, Brian P.; Heanue, Joseph A.; Betts, Timothy D.; Lysel, Michael S. Van

doi:10.1118/1.1339881

Cited by 7 publications

(12 citation statements)

References 15 publications

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“…The x-ray scatter fraction at 100 kVp with 28.0 cm acrylic was 2.9%, in good agreement with a previous measurement made with SBDX under these conditions ͑3.1%͒. 29 The II/CCD system scatter plus veiling glare fraction, interpolated to the position of the contrast disk, was 30%, 33%, 37%, 39%, 43%, 49%, 52%, and 56%, respectively, for 18.6, 21.0, 23.3, 25.6, 28.0, 30.3, 32.6, and 35.0 cm acrylic phantoms. The veiling glare fraction was 10%.…”

Section: Detection Efficiency and Scatter Fractionsupporting

confidence: 91%

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Comparison of entrance exposure and signal-to-noise ratio between an SBDX prototype and a wide-beam cardiac angiographic system

Speidel

Wilfley²,

Star‐Lack³

et al. 2006

Med. Phys.

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The scanning-beam digital x-ray (SBDX) system uses an inverse geometry, narrow x-ray beam, and a 2-mm thick CdTe detector to improve the dose efficiency of the coronary angiographic procedure. Entrance exposure and large-area iodine signal-to-noise ratio (SNR) were measured with the SBDX prototype and compared to that of a clinical cardiac interventional system with image intensifier (II) and charge coupled device (CCD) camera (Philips H5000, MRC-200 x-ray tube, 72 kWp max). Phantoms were 18.6-35.0 cm acrylic with an iohexol-equivalent disk placed at midthickness (35 mg/cm2 iodine radiographic density). Imaging was performed at 15 frame/s, with the disk at mechanical isocenter and an 11-cm object-plane field width. The II/CCD system was operated in cine mode with automatic exposure control. With the SBDX prototype at maximum x-ray output (120 kVp, 24.3 kWp), the SBDX SNR was 107%-69% of the II/CCD SNR, depending on phantom thickness, and the SBDX entrance exposure rate was 10.7-9.3 R/min (9.4-8.2 cGy/min air kerma). For phantoms where an equal-kVp imaging comparison was possible (> or = 23.3 cm), the SBDX SNR ranged from 47% to 69% of the II/CCD SNR while delivering 6% to 9% of the II/CCD entrance exposure rate. From these measurements it was determined that the relative SBDX entrance exposure at equal SNR would be 31%-16%. Results were consistent with a model for relative entrance exposure at equal SNR, which predicted a 3-7 times reduction in entrance exposure due to SBDX's comparatively low scatter fraction (5.5%-8.1% measured, including off-focus radiation), high detector detective quantum efficiency (66%-73%, measured from 70 to 120 kVp), and large entrance field area (1.7x - 2.3x, for the same object-plane field width). With improvements to the system geometry, detector, and x-ray source, SBDX technology is projected to achieve conventional cine-quality SNR over a full range of patient thicknesses, with 5-10 times lower skin dose.

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Section: Detection Efficiency and Scatter Fractionsupporting

confidence: 91%

“…The small difference in detected primary contrast was consistent with a previous comparison study of iodinated vessel contrast. 29…”

Section: Relative Entrance Exposurementioning

confidence: 99%

Comparison of entrance exposure and signal-to-noise ratio between an SBDX prototype and a wide-beam cardiac angiographic system

Speidel

Wilfley²,

Star‐Lack³

et al. 2006

Med. Phys.

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“…It is therefore important to monitor the imaging dose and reduce it, if possible. To this end, a novel x-ray imaging device for interventional fluoroscopic imaging, the scanning-beam digital x-ray (SBDX) system, has been recently developed (Speidel et al 2006a, 2006b, Van Lysel et al 1997, Speidel et al 2001, Fahrig et al 2003). The SBDX imaging system offers a reduction in imaging skin dose.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo model of the scanning beam digital x-ray (SBDX) source

Bazalova¹,

M²,

Wilfley³

et al. 2012

Phys. Med. Biol.

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The scanning-beam digital x-ray (SBDX) system has been developed for fluoroscopic imaging using an inverse x-ray imaging geometry. The SBDX system consists of a large-area x-ray source with a multihole collimator and a small detector. The goal of this study was to build a Monte Carlo (MC) model of the SBDX source as a useful tool for optimization of the SBDX imaging system in terms of its hardware components and imaging parameters. The MC model of the source was built in the EGSnrc/BEAMnrc code and validated using the DOSXYZnrc code and Gafchromic film measurements for 80, 100, and 120 kV x-ray source voltages. The MC simulated depth dose curves agreed with measurements to within 5%, and beam profiles at three selected depths generally agreed within 5%. Exposure rates and half-value layers for three voltages were also calculated from the MC simulations. Patient skin-dose per unit detector-dose was quantified as a function of patient size for all three x-ray source voltages. The skin-dose to detector-dose ratio ranged from 5–10 for a 20 cm thick patient to 1 × 103–1 × 105 for a 50 cm patient for the 120 and 80 kV beams, respectively. Simulations of imaging dose for a prostate patient using common imaging parameters revealed that skin-dose per frame was as low as 0.2 mGy.

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“…The design goal of SBDX is to perform x-ray fluoroscopy and angiography with a several-fold reduction in x-ray dose to the patient and medical staff, while maintaining the image quality offered by a conventional system ͑II/TV or FPI͒. [3][4][5][6] The first reported SBDX prototype 3,4 was designed for fluoroscopic electrophysiology applications. This system was limited to 4.2 kWp source power at 70 kVp, used a YSOscintillator/photomultiplier array, and was capable of recon-structing only one tomosynthetic image plane.…”

Section: Introductionmentioning

confidence: 99%

“…Subsequently the x-ray source, detector, and image reconstructor technologies were redesigned for the higher demands of coronary angiography. 5,6 These changes focused on raising source power, detection efficiency, and the width of the scanned beam in order to increase detected x-ray fluence. The redesign also featured a larger source-detector distance, the capability to simultaneously reconstruct multiple tomosynthetic image planes, and the ability to form a composite of these planes in real time for display to the interventionalist.…”

Section: Introductionmentioning

confidence: 99%

Scanning-beam digital x-ray (SBDX) technology for interventional and diagnostic cardiac angiography

et al. 2006

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The scanning-beam digital x-ray (SBDX) system is designed for x-ray dose reduction in cardiac angiographic applications. Scatter reduction, efficient detection of primary x-rays, and an inverse beam geometry are the main components of the entrance dose reduction strategy. This paper reports the construction of an SBDX prototype, image reconstruction techniques, and measurements of spatial resolution and x-ray output. The x-ray source has a focal spot that is electronically scanned across a large-area transmission target. A multihole collimator beyond the target defines a series of x-ray beams directed at a distant small-area detector array. The prototype has a 23 cm X 23 cm target, 100 X 100 focal spot positions, and a 5 cm X 5 cm CdTe detector positioned 150 cm from the target. With this nonmechanical method of beam scanning, patient images with low detected scatter are generated at up to 30 frame/s. SBDX data acquisition is tomosynthetic. The prototype simultaneously reconstructs 16 planes spaced throughout the cardiac volume using shift-and-add backprojection. Image frames analogous to conventional projection images are generated with a multiplane compositing algorithm. Single-plane versus multiplane reconstruction of contrast-filled coronary arteries is demonstrated with images of the porcine heart. Phantom and porcine imaging studies show multiplane reconstruction is practicable under clinically realistic levels of patient attenuation and cardiac motion. The modulation transfer function for an in-plane slit at mechanical isocenter measured 0.41-0.56 at 1 cycle/mm, depending on the detector element to image pixel interpolation technique. Modeling indicates that desired gains in spatial resolution are achievable by halving the detector element width. The x-ray exposure rate 15 cm below isocenter, without table or patient in the beam, measured 11.5 R/min at 120 kVp, 24.3 kWp and 3.42 R/min at 70 kVp, 14.2 kWp.

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Comparison of vessel contrast measured with a scanning-beam digital x-ray system and an image intensifier/television system

Cited by 7 publications

References 15 publications

Comparison of entrance exposure and signal-to-noise ratio between an SBDX prototype and a wide-beam cardiac angiographic system

Comparison of entrance exposure and signal-to-noise ratio between an SBDX prototype and a wide-beam cardiac angiographic system

Monte Carlo model of the scanning beam digital x-ray (SBDX) source

Scanning-beam digital x-ray (SBDX) technology for interventional and diagnostic cardiac angiography

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