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flat panel detector

Pengwei Wu, Joseph Webster Stayman, Alejandro Sisniega, Wojciech Zbijewski, David Foos, Xiaohui Wang, Nafi Aygun, Robert Stevens, Jeffrey H Siewerdsen
Cone-beam CT (CBCT) systems commonly incorporate a flat-panel detector (FPD) with multiple-gain readout capability to reduce electronic noise and extend dynamic range. In this work, we report a penalized weighted least-squares (PWLS) method for CBCT image reconstruction with a system model that includes the electronic noise characteristics of FPDs, including systems with dynamic-gain or dual-gain (DG) readout in which the electronic noise is spatially varying. Statistical weights in PWLS were modified to account for the contribution of the electronic noise (algorithm denoted PWLS^DG), and the method was combined with a certainty-based approach that improves the homogeneity of spatial resolution (algorithm denoted PWLS_Cert^DG)...
November 14, 2018: Physics in Medicine and Biology
D Behme, N Amelung, T Khakzad, M-N Psychogios
BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms has relevantly changed over the past decades. Multiple new devices such as intrasaccular flow diverters have broadened the treatment spectrum but require very exact aneurysm sizing. In this study, we investigated multidetector and flat panel angiographic CT and digital subtraction imaging as well as different postprocessing methods (multiplanar reconstruction, volume-rendering technique, 3D DSA, and conventional 2D angiography) for their ability to exactly size 2 aneurysm models...
November 8, 2018: AJNR. American Journal of Neuroradiology
Koji Ohara, Satoshi Tominaka, Hiroki Yamada, Masakuni Takahashi, Hiroshi Yamaguchi, Futoshi Utsuno, Takashi Umeki, Atsushi Yao, Kengo Nakada, Michitaka Takemoto, Satoshi Hiroi, Naruki Tsuji, Toru Wakihara
A dedicated apparatus has been developed for studying structural changes in amorphous and disordered crystalline materials substantially in real time. The apparatus, which can be set up on beamlines BL04B2 and BL08W at SPring-8, mainly consists of a large two-dimensional flat-panel detector and high-energy X-rays, enabling total scattering measurements to be carried out for time-resolved pair distribution function (PDF) analysis in the temperature range from room temperature to 873 K at pressures of up to 20 bar...
November 1, 2018: Journal of Synchrotron Radiation
Wenying Wang, Grace J Gang, Jeffrey H Siewerdsen, J Webster Stayman
PURPOSE: Model-based iterative reconstruction (MBIR) algorithms such as penalized-likelihood (PL) methods exhibit data-dependent and shift-variant properties. Image quality predictors have been derived to prospectively estimate local noise and spatial resolution, facilitating both system hardware design and tuning of reconstruction methods. However, current MBIR image quality predictors rely on idealized system models, ignoring physical blurring effects and noise correlations found in real systems...
October 29, 2018: Medical Physics
Naoya Kozono, Takamitsu Okada, Naohide Takeuchi, Satoshi Hamai, Hidehiko Higaki, Takeshi Shimoto, Satoru Ikebe, Hirotaka Gondo, Yoshitaka Nakanishi, Takahiro Senju, Yasuharu Nakashima
BACKGROUND: There are no previous studies on the acromiohumeral distance in shoulders with large-to-massive full-thickness rotator cuff tears. In this study, the acromiohumeral distance in rotator cuff tear and healthy shoulders was measured using 3D-to-2D model-to-image registration techniques. METHODS: The dynamic glenohumeral kinematics during scapular plane abduction and axial rotation were analyzed in 11 rotator cuff tear patients and 10 healthy control subjects...
July 26, 2018: Clinical Biomechanics
Niral M Sheth, Wojciech Zbijewski, Matthew W Jacobson, Godwin Abiola, Gerhard Kleinszig, Sebastian Vogt, Stefan Soellradl, Jens Bialkowski, William S Anderson, Clifford R Weiss, Greg M Osgood, Jeffrey H Siewerdsen
PURPOSE: Indirect-detection CMOS flat-panel detectors (FPDs) offer fine pixel pitch, fast readout, and low electronic noise in comparison to current a-Si:H FPDs. This work investigates the extent to which these potential advantages affect imaging performance in mobile C-arm fluoroscopy and cone-beam CT (CBCT). METHODS: FPDs based on CMOS (Xineos 3030HS, 0.151 mm pixel pitch) or a-Si:H (PaxScan 3030X, 0.194 mm pixel pitch) sensors were outfitted on equivalent mobile C-arms for fluoroscopy and CBCT...
October 19, 2018: Medical Physics
Kenneth A Fetterly
PURPOSE: Electronic noise associated with passive pixel (PP) x-ray angiography flat panel detectors is known to compromise fluoroscopic image quality. An active pixel (AP) crystalline silicon x-ray detector with potential for reduced influence of electronic noise is commercially available. The purpose of this work was to compare the performance of the AP vs PP x-ray angiography detectors over a detector target dose (DTD) range relevant for invasive cardiology procedures. METHODS: A total of 16 passive pixel detector systems representing two models and two active pixel detector systems of a single model were tested...
October 12, 2018: Medical Physics
Ling Zhu, Yi Chen, Jie Yang, Xiaofeng Tao, Yan Xi
OBJECTIVE: Metal artifacts are highly common in dental computed tomography (CT) images because of the high X-ray attenuation of metallic dental fillings and implants. This study presents an evaluation of the virtual monochromatic imaging for metal artefact reduction by a recently introduced dental spectral cone beam CT (SCBCT), which is the first commercial dental spectral CBCT with flat-panel detector. METHODS: We carried out phantom experiments and clinical trials in this study...
October 9, 2018: Dento Maxillo Facial Radiology
M P Duarte Conde, A M de Korte, F J A Meijer, R Aquarius, H D Boogaarts, R H M A Bartels, J de Vries
BACKGROUND AND PURPOSE: This was a pilot study to explore the diagnostic accuracy and safety of subtraction CTA combined with a single-energy metal artifact reduction algorithm (SEMAR) compared to DSA for the evaluation of intracranial aneurysm occlusion after flow diverter treatment. MATERIALS AND METHODS: We included patients treated with a flow diverter for an unruptured intracranial aneurysm between November 2015 and November 2016. The patient cohort comprised 2 groups: those who underwent follow-up imaging 1 month after flow-diverter treatment and those with a known residual intracranial aneurysm after flow diverter treatment who underwent imaging at regular follow-ups...
October 4, 2018: AJNR. American Journal of Neuroradiology
Satoshi Tanabe, Osamu Umetsu, Toshikazu Sasage, Satoru Utsunomiya, Ryota Kuwabara, Toshiki Kuribayashi, Hiromasa Takatou, Gen Kawaguchi, Hidefumi Aoyama
BACKGROUND & AIMS: A new real-time tracking radiotherapy (RTRT) system, the SyncTraX FX4 (Shimadzu, Kyoto, Japan), consisting of four X-ray tubes and four ceiling-mounted flat panel detectors (FPDs) combined with a linear accelerator, was installed at Uonuma Kikan Hospital (Niigata, Japan) for the first time worldwide. In addition to RTRT, the SyncTraX FX4 system enables bony structure-based patient verification. Here we provide the first report of this system's clinical commissioning for intracranial stereotactic radiotherapy (SRT)...
November 2018: Journal of Applied Clinical Medical Physics
Avilash Cramer, Jake Hecla, Dufan Wu, Xiaochun Lai, Tim Boers, Kai Yang, Tim Moulton, Steven Kenyon, Zaven Arzoumanian, Wolfgang Krull, Keith Gendreau, Rajiv Gupta
Computed tomography (CT) is used to diagnose many emergent medical conditions, including stroke and traumatic brain injuries. Unfortunately, the size, weight, and expense of CT systems make them largely inaccessible for patients outside of major hospitals. We have designed a module containing multiple miniature x-ray sources that could allow for CT systems to be significantly lighter, smaller, and cheaper, and to operate without any moving parts. We have developed a novel photocathode-based x-ray source, created by depositing a thin film of magnesium on an electron multiplier...
September 21, 2018: Scientific Reports
K S Kim, S Y Kang, C K Park, G A Kim, S Y Park, Hyosung Cho, C W Seo, D Y Lee, H W Lim, H W Lee, J E Park, T H Woo, J E Oh
In cone-beam computed tomography (CBCT), reconstructed images are inherently degraded, restricting its image performance, due mainly to imperfections in the imaging process resulting from detector resolution, noise, X-ray tube's focal spot, and reconstruction procedure as well. Thus, the recovery of CBCT images from their degraded version is essential for improving image quality. In this study, we investigated a compressed-sensing (CS)-based blind deconvolution method to solve the blurring problem in CBCT where both the image to be recovered and the blur kernel (or point-spread function) of the imaging system are simultaneously recursively identified...
September 20, 2018: Journal of Digital Imaging: the Official Journal of the Society for Computer Applications in Radiology
Monica Abella, Claudia de Molina, Nerea Ballesteros, Alba García-Santos, Álvaro Martínez, Inés García, Manuel Desco
In scenarios where the use of a Computed Tomography (CT) is difficult, such as during surgery or in the ICU, the use of a C-arm system to generate tomographic information could contribute with interesting additional clinical information. Recent days are seeing the development of the so-called cone-beam CT (CBCT) based on advanced motorized isocentric C-arm systems. To be able to make use of more basic C-arm systems, apart from the geometric non-idealities common to any CBCT, we need to address other difficulties...
2018: PloS One
Keith Smith, James Crowhurst, Darren Walters, Deborah Starkey
OBJECTIVE: This study compares the performance of bi-plane coronary angiography against single plane angiography in terms of the volume of contrast used (ml) and the total dose-area product (DAP) (μGym2 ) to the patient measured directly via flat panel detectors. METHODS: A total of 5176 adult diagnostic cardiac angiograms from a hospital in Brisbane, Australia were retrospectively studied. Patients with aortograms, iliac or femoral artery imaging, and stenting or graft interventions were excluded...
September 21, 2018: British Journal of Radiology
Adrian Howansky, A R Lubinsky, Katsuhiko Suzuki, S Ghose, Wei Zhao
PURPOSE: Turbid (powder or columnar-structured) scintillators are widely used in indirect flat panel detectors (I-FPDs) for scientific, industrial, and medical radiography. Light diffusion and absorption within these scintillators is expected to cause depth-dependent variations in their x ray conversion gain and spatial blur. These variations degrade the detective quantum efficiency of I-FPDs at all spatial frequencies. Despite their importance, there are currently no established methods for directly measuring scintillator depth effects...
November 2018: Medical Physics
Qiushui Chen, Jing Wu, Xiangyu Ou, Bolong Huang, Jawaher Almutlaq, Ayan A Zhumekenov, Xinwei Guan, Sanyang Han, Liangliang Liang, Zhigao Yi, Juan Li, Xiaoji Xie, Yu Wang, Ying Li, Dianyuan Fan, Daniel B L Teh, Angelo H All, Omar F Mohammed, Osman M Bakr, Tom Wu, Marco Bettinelli, Huanghao Yang, Wei Huang, Xiaogang Liu
The rising demand for radiation detection materials in many applications has led to extensive research on scintillators1-3 . The ability of a scintillator to absorb high-energy (kiloelectronvolt-scale) X-ray photons and convert the absorbed energy into low-energy visible photons is critical for applications in radiation exposure monitoring, security inspection, X-ray astronomy and medical radiography4,5 . However, conventional scintillators are generally synthesized by crystallization at a high temperature and their radioluminescence is difficult to tune across the visible spectrum...
September 2018: Nature
Daiki Aburakawa, Yoshikazu Ogawa, Kenichi Sato, Kuniyasu Niizuma, Teiji Tominaga
Giant pituitary adenomas carry higher surgical risks despite recent advances in microsurgical and/or endoscopic surgery. In particular, postoperative acute catastrophic changes without major vessel disturbance are still extremely difficult to predict, and may manifest as postoperative pituitary apoplexy with very poor outcomes. These changes are associated with injuries to the capillary intratumoral feeders and/or drainers, which frequently have diameters of less than 300µm, and result in drastic hemodynamic changes...
August 2018: No Shinkei Geka. Neurological Surgery
Nivedh Manohar, Francisco J Reynoso, Sang Hyun Cho
PURPOSE: This report describes upgrades and performance characterization of an experimental benchtop cone-beam x-ray fluorescence computed tomography (XFCT) system capable of determining the spatial distribution and concentration of metal probes such as gold nanoparticles (GNPs). Specifically, a high-power (~3 kW) industrial x-ray source and transmission CT capability were deployed in the same platform under the cone-beam geometry. METHODS: All components of the system are described in detail, including the x-ray source, imaging stage, cadmium-telluride detector for XFCT, and flat-panel detector for transmission CT imaging...
October 2018: Medical Physics
Adrien Kaladji, Alexandre Villena, Remy Pascot, Florent Lalys, Anne Daoudal, Elodie Clochard, Antoine Lucas, Alain Cardon
INTRODUCTION: Fusion imaging is a technique that facilitates endovascular navigation but is only available in hybrid rooms. The goal of this study was to evaluate the feasibility of fusion imaging with a mobile C-arm in a conventional operating room through the use of an angio-navigation station. METHODS: From May 2016 to June 2017, the study included all patients who underwent an aortic stent graft procedure in a conventional operating room with a mobile flat-panel detector (Cios Alpha, Siemens) connected to an angio-navigation station (EndoNaut, Therenva)...
August 6, 2018: Annals of Vascular Surgery
Noriyuki Sakai, Katsuyuki Tabei, Jiro Sato, Toshikazu Imae, Yuichi Suzuki, Shigeharu Takenaka, Keiichi Yano, Osamu Abe
OBJECTIVES: To (a) evaluate the interpolation frames of frame rate conversion (FRC) compared with fluoroscopic frames of conventional method, and (b) compare radiation dose and fluoroscopy time between various clinical examinations without and with FRC retrospectively. METHODS: This study consisted of a basic study and a clinical retrospective analysis. The radiation dosimetry, visual assessment and measurements of contrast to noise ratio were examined. Similarity between interpolation frames and fluoroscopic frames was evaluated using normalised cross-correlation values...
July 9, 2018: European Radiology
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