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 cmx23 cm target, 100x100 focal spot positions, and a 5 cmx5 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 realisticmore » 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.« less
The feasibility of making regional perfusion measurements using a tomosynthetic digital subtraction angiography (TDSA) acquisition has been demonstrated. The study of tomosynthetic perfusion measurements was motivated by the clinical desire for perfusion measurements in an interventional angiography suite. These pilot studies were performed using the scanning-beam digital x-ray (SBDX) system which is an inverse-geometry imaging device which utilizes an electromagnetically-scanned x-ray source, a...
We propose an inverse-geometry volumetric CT system for acquiring a 15-cm volume in one rotation with negligible cone-beam artifacts. The system uses a large-area scanned source and a smaller detector array. This note describes two feasibility investigations. The first examines data sufficiency in the transverse planes. The second predicts the signal-to-noise ratio(SNR) compared to a conventional scanner. Results showed sufficient sampling of the full volume in less than 0.5 s and, when compared...
Digital x-ray tomosynthesis is a technique for producing slice images using conventional x-ray systems. It is a refinement of conventional geometric tomography, which has been known since the 1930s. In conventional geometric tomography, the x-ray tube and image receptor move in synchrony on opposite sides of the patient to produce a plane of structures in sharp focus at the plane containing the fulcrum of the motion; all other structures above and below the fulcrum plane are blurred and thus les...
Vessel contrast was measured in the fluoroscopic images produced by a scanning-beam digital x-ray (SBDX) system and an image intensifier/television (II/TV) based system. The SBDX system electronically scans a series of pencil x-ray beams across the patient, each of which is directed at a distant small-area detector array. The reduction in detected scatter achieved with this geometry was expected to provide an increase in imagecontrast. Vessel contrast was evaluated from images of a phantom conta...
An advanced Scanning-Beam Digital X-ray (SBDX) system for cardiac angiography has been constructed. The 15-kW source operates at 70 - 120 kVp and has an electron beam that is electromagnetically scanned across a 23-cm X 23-cm transmission target. The target is directly liquid cooled for continuous full-power operation and is located behind a focused source collimator. The collimator is a rectangular grid of 100 X 100 apertures whose axes are aligned with the center of the detector array. X-ray b...
The Scanning-Beam Digital X-ray (SBDX) system promises low- dose cardiac fluoroscopy and angiography with excellent image quality. The system demands a detector capable of high count rates and excellent detection efficiency. Cadmium zinc telluride (CdZnTe) is well suited to these requirements. The SBDX detector comprises sixteen 3-mm-thick, 13.5 mm X 13.5 mm tiles arranged in a 4 X 4 array. Each tile has 144 imaging elements. Thus, the entire detector measures 54.0 mm X 54.0 mm and includes 2,30...
Last. Michael A. Speidel(UW: University of Wisconsin-Madison)H-Index: 11
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A prototype scanning-beam digital x-ray (SBDX) system for cardiac fluoroscopy has been constructed. The unique geometry and absence of detected x-ray scatter in the SBDX image promises to provide image quality equivalent to a conventional image-intensifier-based fluoroscopic system at substantially reduced x-ray exposure to patient and staff. In order to measure the SBDX exposure advantage, a contrast- detail study was performed comparing SBDX and a conventional cardiac fluoroscopic system. Low-...
Since 1992, the U.S. Food and Drug Administration (FDA) has received reports of radiation-induced injuries to the skin in patients who had undergone fluoroscopically guided interventional procedures. The reports were investigated to determine the procedure- or equipment-related factors that may have contributed to the injury. The injuries ranged in severity from erythema to moist desquamation to tissue necrosis that required skin grafting. They occurred after a variety of interventional procedur...
A prototype scanning-beam digital x-ray system for cardiac fluoroscopy has been constructed. Source-to-detector distance is 94 cm with the subject positioned near the source. The 4-kW source operates at 70-110 kVp and has an electromagnetically-scanned 25-cm-diameter transmission target. The target is at ground potential and is directly liquid cooled for continuous full-power operation. The source collimator has 22,000 holes whose axes are aligned with the center of the detector array. Beam dive...
Measurements were made of the MTF(f), NPS(f), and DQE(f) of four generations of computed radiography(CR) imaging plates and three generations of CR image readers. The MTF generally showed only a minor change between generations of plates and readers, but the DQE(f) has improved substantially from a very early plate/reader combination to a more recent one. The DQE in the more recent plate/reader combination is 1.3× greater at low frequencies and about 3× greater at high frequencies than the much ...
#1Qinghao Chen(WashU: Washington University in St. Louis)
#2Shuang Zhou(WashU: Washington University in St. Louis)H-Index: 1
Last. Tiezhi Zhang(WashU: Washington University in St. Louis)H-Index: 14
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PURPOSE A tetrahedron beam (TB) X-ray system with a linear X-ray source array and a linear detector array positioned orthogonal to each other may overcome the X-ray scattering problem of traditional cone-beam X-ray systems. We developed a TB imaging benchtop system using a linear array X-ray source to demonstrate the principle and benefits of TB imaging. METHODS A multi-pixel thermionic emission X-ray (MPTEX) source with 48 focal spots in 4-mm spacing was developed in-house. The X-ray beams are ...
#1Mang Feng(UW: University of Wisconsin-Madison)H-Index: 5
#2Xu Ji(UW: University of Wisconsin-Madison)H-Index: 5
Last. Ke Li(UW: University of Wisconsin-Madison)H-Index: 14
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Large-area photon counting detectors (PCDs) are usually built by tiling multiple semiconductor panels that often have slightly different spectral responses to input x-rays. As a result of this spectral inconsistency, experimental PCD-CT images of large, human-sized objects may show high-frequency ring artifacts and low-frequency band artifacts. Due to the much larger width of the bands compared with the rings, the concentric artifact problem in PCD-CT images of human-sized objects cannot be adeq...
Abstract null null Replacing moving mechanics in computed tomography (CT) and digital breast tomosynthesis (DBT) has inspired numerous projects to develop alternative X-ray sources. While less suitable for CT, DBT is a viable target application for the multi-X-ray-source array tube suggested in Becker, A.E., et al. (2020): A prototype Multi-X-ray-source array (MXA) for digital breast tomosynthesis. Physics in Medicine & Biology, 65(23), 235033. The proposed prototype MXA tube comprises rotating ...
The spread of COVID-19 disease rapidly worldwide and the increase in deaths are a threat to humanity. This threat prompted researchers in deep learning (DL) to find ways to diagnose COVID-19 from computed tomography (CT) or x-rays. Working deep learning identifies the infection accurately through medical imaging, and the practising radiologist can diagnose the illness.This survey will discuss the reason behind deep learning and the technology used in medical image processing. Exposure to the mos...
#2Serestina Viriri(UKZN: University of KwaZulu-Natal)H-Index: 12
This paper aims to investigate the use of transfer learning architectures in the detection of COVID-19 from CT lung scans The study evaluates the performances of various transfer learning architectures, as well as the effects of the standard Histogram Equalization and Contrast Limited Adaptive Histogram Equalization The findings of this study suggest that transfer learning-based frameworks are an alternative to the contemporary methods used to detect the presence of the virus in patients The hig...
The universal transmission of pandemic COVID-19 (Coronavirus) causes an immediate need to commit in the fight across the whole human population. The emergencies for human health care are limited for this abrupt outbreak and abandoned environment. In this situation, inventive automation like computer vision (machine learning, deep learning, artificial intelligence), medical imaging (computed tomography, X-Ray) has developed an encouraging solution against COVID-19. In recent months, different tec...
Kilovoltage (kV) x-rays are most commonly used for diagnostic imaging due to their sensitivity to tissue composition. In radiation therapy (RT), due to their fast attenuation, kV x-rays are typically only used for superficial irradiation of skin cancer and for intra-operative RT (IORT). Recently, however, a number of kV RT techniques have emerged. In this review article, we provide a brief overview of the use of kV x-rays for RT. Various kV x-ray source technologies suitable for RT, such as conv...
