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https://www.readbyqxmd.com/read/30315578/performance-assessment-of-active-vs-passive-pixel-x-ray-angiography-detector-systems-using-a-bias-corrected-channelized-hotelling-observer-and-adult-patient-equivalent-experimental-conditions
#1
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
https://www.readbyqxmd.com/read/30299983/evaluation-of-the-dental-spectral-cone-beam-ct-for-metal-artifact-reduction
#2
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
https://www.readbyqxmd.com/read/30287460/subtraction-cta-an-alternative-imaging-option-for-the-follow-up-of-flow-diverter-treated-aneurysms
#3
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
https://www.readbyqxmd.com/read/30273444/clinical-commissioning-of-a-new-patient-positioning-system-synctrax-fx4-for-intracranial-stereotactic-radiotherapy
#4
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)...
October 1, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/30242169/stationary-computed-tomography-for-space-and-other-resource-constrained-environments
#5
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
https://www.readbyqxmd.com/read/30238344/a-compressed-sensing-based-blind-deconvolution-method-for-image-deblurring-in-dental-cone-beam-computed-tomography
#6
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
https://www.readbyqxmd.com/read/30212543/enabling-tomography-with-low-cost-c-arm-systems
#7
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
https://www.readbyqxmd.com/read/30209953/bi-plane-and-single-plane-angiography-a-study-to-compare-contrast-usage-and-radiation-doses-for-adult-cardiac-patients-in-diagnostic-studies
#8
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
https://www.readbyqxmd.com/read/30193407/an-apparatus-and-method-for-directly-measuring-the-depth-dependent-gain-and-spatial-resolution-of-turbid-scintillators
#9
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...
September 7, 2018: Medical Physics
https://www.readbyqxmd.com/read/30150772/all-inorganic-perovskite-nanocrystal-scintillators
#10
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
https://www.readbyqxmd.com/read/30135291/-surgical-planning-for-a-giant-pituitary-adenoma-based-on-evaluation-of-the-fine-feeding-system-and-angioarchitecture-a-case-report
#11
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
https://www.readbyqxmd.com/read/30125950/technical-note-a-benchtop-cone-beam-x-ray-fluorescence-computed-tomography-xfct-system-with-a-high-power-x-ray-source-and-transmission-ct-imaging-capability
#12
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
https://www.readbyqxmd.com/read/30092429/fusion-imaging-for-evar-with-mobile-c-arm
#13
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
https://www.readbyqxmd.com/read/29987416/radiation-dose-reduction-with-frame-rate-conversion-in-x-ray-fluoroscopic-imaging-systems-with-flat-panel-detector-basic-study-and-clinical-retrospective-analysis
#14
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
https://www.readbyqxmd.com/read/29970119/dynamic-hip-kinematics-during-squatting-before-and-after-total-hip-arthroplasty
#15
Keisuke Komiyama, Satoshi Hamai, Daisuke Hara, Satoru Ikebe, Hidehiko Higaki, Kensei Yoshimoto, Kyohei Shiomoto, Hirotaka Gondo, Yifeng Wang, Yasuharu Nakashima
BACKGROUND: The difference in in vivo kinematics before and after total hip arthroplasty (THA) for the same subjects and the clearance between the liner and neck during squatting have been unclear. The purpose of the present study was to clarify (1) the changes in the in vivo kinematics between prosthetic hips and osteoarthritis hips of the same subjects and (2) the extent of the liner-to-neck clearance during squatting under weight-bearing conditions. METHODS: This study consisted of 10 patients who underwent unilateral THA for symptomatic osteoarthritis...
July 3, 2018: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/29951253/new-advances-in-intra-operative-imaging-in-trauma
#16
Peter H Richter, Florian Gebhard, Alexander Eickhoff, Konrad Schütze
The invention of flat-panel detectors led to a revolution in medical imaging. The major benefits of this technology are a higher image quality and dose reduction. Flat-panel detectors have proved to be superior to standard C-arms (= C-arm with radiograph source and image intensifier).Cone-beam computed tomography (cone-beam CT) is a 3D data set, which can be acquired with a flat-panel detector. The cone-shaped beam is used for 3D data generation. For cone-beam CT acquisition, the flat-panel detector rotates around the patient lying on the operating table...
May 2018: EFORT Open Reviews
https://www.readbyqxmd.com/read/29947938/-imaging-in-acute-ischemic-stroke-using-automated-postprocessing-algorithms
#17
REVIEW
K Egger, C Strecker, E Kellner, H Urbach
There are several automated analytical methods to detect thromboembolic vascular occlusions, the infarct core and the potential infarct-endangered tissue (tissue at risk) by means of multimodal computed tomography (CT) and magnetic resonance imaging (MRI). The infarct core is more reliably visualized by diffusion-weighted imaging (DWI) MRI or CT perfusion than by native CT. The extent of tissue at risk and endangerment can only be estimated; however, it seems essential whether "tissue at risk" actually exists...
August 2018: Der Nervenarzt
https://www.readbyqxmd.com/read/29934087/radiation-exposure-to-surgeon-and-assistant-during-flat-panel-mini-c-arm-fluoroscopy-in-hand-and-wrist-surgical-procedures
#18
Juliaan R M van Rappard, Tijmen de Jong, Willy A Hummel, Marco J P F Ritt, Chantal M Mouës
PURPOSE: During mini C-arm fluoroscopy, both the patient and surgical team are exposed to scatter radiation. The objective of this study was to quantify body, thyroid, and hand radiation exposure to surgeon and assistant during intraoperative use of flat panel mini C-arm fluoroscopy in hand and wrist surgical procedures. METHODS: Over 5 months, the surgeon's and assistant's radiation exposure was recorded during all osseous hand and wrist surgical procedures. Whole-body and thyroid radiation exposure were measured with 2 types of dosimeters: a photon thermoluminescence detector and a RaySafe i2 real-time dosimeter...
June 19, 2018: Journal of Hand Surgery
https://www.readbyqxmd.com/read/29903933/performance-evaluation-of-g8-a-high-sensitivity-benchtop-preclinical-pet-ct-tomograph
#19
Zheng Gu, Richard Taschereau, Nam Vu, David L Prout, Robert W Silverman, Jason Lee, Arion F Chatziioannou
G8 is a bench top integrated PET/CT scanner dedicated to high sensitivity and high resolution imaging of mice. This work characterizes its National Electrical Manufacturers Association (NEMA) NU4-2008 performance where applicable and also provides an assessment of the basic imaging performance of the CT subsystem. Methods: The PET subsystem in G8 consists of four flat-panel type detectors arranged in a box like geometry. Each panel consists of two modules of a 26 × 26 pixelated bismuth germanate (BGO) scintillator array with individual crystals measuring 1...
June 14, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/29899592/use-of-material-decomposition-in-the-context-of-neurovascular-intervention-using-standard-flat-panel-and-a-high-resolution-cmos-detector
#20
A R Podgorsak, A C Venkataraman, S V Setlur Nagesh, D R Bednarek, S Rudin, A Siddiqui, C N Ionita
The imaging of endovascular devices during neurovascular procedures such as the coiling of aneurysms guided with CBCT imaging may be challenging due to the presence of highly attenuating materials such as platinum in the coil and stent marker, nickel-titanium in the stent, iodine in the contrast agent, and tantalum in the embolization agent. The use of dual-energy imaging followed by a basis material decomposition image processing-scheme may improve the feature separation and recognition. Two sets of testing were performed to validate this concept...
February 2018: Proceedings of SPIE
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