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https://www.readbyqxmd.com/read/28983677/reduced-dose-c-arm-computed-tomography-applications-at-a-pediatric-institution
#1
Michael Acord, Sphoorti Shellikeri, Seth Vatsky, Abhay Srinivasan, Ganesh Krishnamurthy, Marc S Keller, Anne Marie Cahill
BACKGROUND: Reduced-dose C-arm computed tomography (CT) uses flat-panel detectors to acquire real-time 3-D images in the interventional radiology suite to assist with anatomical localization and procedure planning. OBJECTIVE: To describe dose-reduction techniques for C-arm CT at a pediatric institution and to provide guidance for implementation. MATERIALS AND METHODS: We conducted a 5-year retrospective study on procedures using an institution-specific reduced-dose protocol: 5 or 8 s Dyna Rotation, 248/396 projection images/acquisition and 0...
October 5, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/28959083/characterization-of-continuous-and-pulsed-emission-modes-of-a-hybrid-micro-focus-x-ray-source-for-medical-imaging-applications
#2
Muhammad U Ghani, Molly D Wong, Liqiang Ren, Di Wu, Bin Zheng, John X Rong, Xizeng Wu, Hong Liu
The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16-50 μm as the source output power changes from 10-39 W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution. Source output was measured using an ionization chamber for various tube voltages (kVs) with varying current (μA) and distances...
May 1, 2017: Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
https://www.readbyqxmd.com/read/28958735/an-integrated-system-for-clinical-treatment-verification-of-hdr-prostate-brachytherapy-combining-source-tracking-with-pretreatment-imaging
#3
Ryan L Smith, Max Hanlon, Vanessa Panettieri, Jeremy L Millar, Bronwyn Matheson, Annette Haworth, Rick D Franich
PURPOSE: High-dose-rate (HDR) prostate brachytherapy treatment is usually delivered in one or a few large dose fractions. Poor execution of a planned treatment could have significant clinical impact, as high doses are delivered in seconds, and mistakes in an individual fraction cannot be easily rectified. Given that most potential errors in HDR brachytherapy ultimately lead to a geographical miss, a more direct approach to verification of correct treatment delivery is to directly monitor the position of the source throughout the treatment...
September 22, 2017: Brachytherapy
https://www.readbyqxmd.com/read/28940528/assessment-of-a-photon-counting-detector-for-a-dual-energy-c-arm-angiographic-system
#4
Moiz Ahmad, Rebecca Fahrig, Leland Pung, Martin Spahn, Niko S Köster, Silke Reitz, Teri Moore, Jang-Hwan Choi, Waldo Hinshaw, Yan Xia, Kerstin Müller
PURPOSE: This article presents the implementation and assessment of photon-counting dual-energy x-ray detector technology for angiographic C-arm systems in interventional radiology. METHODS: A photon-counting detector was successfully integrated into a clinical C-arm CT system. Detector performance was assessed using image uniformity metrics in both 2D projections and 3D cone-beam computed tomography (CBCT) images. Uniform exposure fields were acquired to analyze projection images and scans of a homogeneous cylinder phantom were taken to analyze 3D reconstructions...
September 22, 2017: Medical Physics
https://www.readbyqxmd.com/read/28893700/comparison-of-radiation-exposure-during-endovascular-treatment-of-peripheral-arterial-disease-with-flat-panel-detectors-on-mobile-c-arm-vs-fixed-systems
#5
Marie Guillou, Blandine Maurel, Hatem Necib, Pierre-Alexandre Vent, Alain Costargent, Philippe Chaillou, Yann Gouëffic, Adrien Kaladji
PURPOSE: Flat-panel detectors on mobile C-arm (MC-arm) systems are currently challenging fixed C-arm (FC-arm) systems used in hybrid operating rooms. MC-arm systems offer an alternative to FC-arm systems in the endovascular treatment of peripheral arterial disease (PAD) but their efficiency has not been evaluated comparatively. METHODS: Two series of patients undergoing arteriography with intention to treat were included. Each series consisted of two non-randomized groups: an MC-arm group and an FC-arm group...
September 8, 2017: Annals of Vascular Surgery
https://www.readbyqxmd.com/read/28837233/real-time-tomosynthesis-for-radiation-therapy-guidance
#6
Scott S Hsieh, Lydia W Ng
PURPOSE: Fluoroscopy has been a tool of choice for monitoring treatments or interventions because of its extremely fast imaging times. However, the contrast obtained in fluoroscopy may be insufficient for certain clinical applications. In stereotactic ablative radiation therapy of the lung, fluoroscopy often lacks sufficient contrast for gating treatment. The purpose of this work is to describe and assess a real-time tomosynthesis design that can produce sufficient contrast for guidance of lung tumor treatment within a small field of view...
August 24, 2017: Medical Physics
https://www.readbyqxmd.com/read/28811040/implant-specific-follow-up-imaging-of-treated-intracranial-aneurysms-tof-mra-vs-metal-artifact-reduced-intravenous-flat-panel-computed-tomography-angiography-fpcta
#7
N H Hänsel, G A Schubert, B Scholz, O Nikoubashman, A E Othman, M Wiesmann, R Pjontek, M A Brockmann
AIM: To compare the diagnostic quality of time-of-flight magnetic resonance angiography (TOF-MRA) and metal-artefact-reduction (MAR) flat-panel-detector computed tomography angiography (FPCTA) and to determine the imaging technique best suited for evaluation endovascular and surgically treated aneurysms. METHODS: The image quality of TOF-MRA and MAR-FPCTA of 44 intracranial implants (coiling: n=20; clipping: n=15; coiling + stenting: n=9) in a patient cohort of 25 was evaluated by two independent readers...
August 12, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28760084/optimal-dilution-of-contrast-medium-for-quantitating-parenchymal-blood-volume-using-a-flat-panel-detector
#8
Takumi Kuriyama, Nobuyuki Sakai, Mikiya Beppu, Chiaki Sakai, Hirotoshi Imamura, Iwao Kojima, Katsuhiro Masago, Nobuyuki Katakami
Objective Similar to perfusion studies after acute ischemic stroke, measuring cerebral blood volume (CBV) via C-arm computed tomography before and after therapeutic interventions may help gauge subsequent revascularization. We tested serial dilutions of intra-arterial injectable contrast medium (CM) to determine the optimal CM concentration for quantifying parenchymal blood volume by flat-panel detector imaging (FD-PBV). Methods CM was diluted via saline power injector, instituting time delays for FD-PBV studies...
January 1, 2017: Journal of International Medical Research
https://www.readbyqxmd.com/read/28649157/use-of-patient-specific-3d-printed-neurovascular-phantoms-to-evaluate-the-clinical-utility-of-a-high-resolution-x-ray-imager
#9
S V Setlur Nagesh, M Russ, C N Ionita, D Bednarek, S Rudin
Modern 3D printing technology can fabricate vascular phantoms based on an actual human patient with a high degree of precision facilitating a realistic simulation environment for an intervention. We present two experimental setups using 3D printed patient-specific neurovasculature to simulate different disease anatomies. To simulate the human neurovasculature in the Circle of Willis, patient-based phantoms with aneurysms were 3D printed using a Objet Eden 260V printer. Anthropomorphic head phantoms and a human skull combined with acrylic plates simulated human head bone anatomy and x-ray attenuation...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28637959/examination-of-dose-reduction-using-image-noise-reduction-technology-in-cardiovascular-x-ray-systems
#10
Takaya Saijo, Shigenobu Seguchi
The aim of this study is to establish radiation exposure dose reduction protocols during cardiac intervention by decreasing the entrance dose at flat panel detector (FPD) with image quality evaluations. For measuring entrance surface dose (ESD), we have used a Radical 9015 dosimeter (6 cc ion chamber) placed under 20 cm thick acrylic plates at the patient's entrance reference point. We performed an image quality assessment based on quantitative as well as visual evaluation of the images obtained via current and dose reduction protocols...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28632551/comparative-study-of-c-arms-for-intraoperative-3-dimensional-imaging-and-navigation-in-minimally-invasive-spine-surgery-part-i-applicability-and-image-quality
#11
Jan-Helge Klingler, Ronen Sircar, Christian Scheiwe, Evangelos Kogias, Florian Volz, Marie T Krüger, Ulrich Hubbe
STUDY DESIGN: This was a retrospective analysis. OBJECTIVE: This study compares 2 different 3-dimensional (3D) C-arm devices for intraoperative imaging and navigation with regard to clinical applicability and image quality. SUMMARY OF BACKGROUND DATA: Minimally invasive spine surgery requires intraoperative imaging techniques to adequately visualize the unexposed spine. For this purpose, mobile 3D C-arms became available along with the evolution of intraoperative navigation techniques...
July 2017: Clinical Spine Surgery
https://www.readbyqxmd.com/read/28626289/comparison-of-high-resolution-x-ray-detectors-with-conventional-fpds-using-experimental-mtfs-and-apodized-aperture-pixel-design-for-reduced-aliasing
#12
A Shankar, M Russ, S Vijayan, D R Bednarek, S Rudin
Apodized Aperture Pixel (AAP) design, proposed by Ismailova et. al, is an alternative to the conventional pixel design(1). The advantages of AAP processing with a sinc filter in comparison with using other filters include non-degradation of MTF values and elimination of signal and noise aliasing, resulting in an increased performance at higher frequencies, approaching the Nyquist frequency(3). If high resolution small field-of-view (FOV) detectors with small pixels used during critical stages of Endovascular Image Guided Interventions (EIGIs) could also be extended to cover a full field-of-view typical of flat panel detectors (FPDs) and made to have larger effective pixels, then methods must be used to preserve the MTF over the frequency range up to the Nyquist frequency of the FPD while minimizing aliasing...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28625472/3d-catheter-reconstruction-in-hdr-prostate-brachytherapy-for-pre-treatment-verification-using-a-flat-panel-detector
#13
Ryan L Smith, Annette Haworth, Vanessa Panettieri, Jeremy L Millar, Rick D Franich
PURPOSE: High dose rate prostate brachytherapy is a widely-practiced treatment, delivering large conformal doses in relatively few treatment fractions. Inter- and intra-fraction catheter displacements have been reported. Unrecognized displacement can have a significant impact on dosimetry. Knowledge of the implant geometry at the time of treatment is important for ensuring safe and effective treatment. In this work we demonstrate a method to reconstruct the catheter positions pre-treatment, using a 'shift' imaging technique, and perform registration with the treatment plan for verification relative to the prostate...
July 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28624018/difference-in-the-craniocaudal-gradient-of-the-maximum-pixel-value-change-rate-between-chronic-obstructive-pulmonary-disease-patients-and-normal-subjects-using-sub-mgy-dynamic-chest-radiography-with-a-flat-panel-detector-system
#14
Yoshitake Yamada, Masako Ueyama, Takehiko Abe, Tetsuro Araki, Takayuki Abe, Mizuki Nishino, Masahiro Jinzaki, Hiroto Hatabu, Shoji Kudoh
OBJECTIVES: To compare the craniocaudal gradients of the maximum pixel value change rate (MPCR) during tidal breathing between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography. MATERIALS AND METHODS: This prospective study was approved by the institutional review board and all participants provided written informed consent. Forty-three COPD patients (mean age, 71.6±8.7 years) and 47 normal subjects (non-smoker healthy volunteers) (mean age, 54...
July 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28609790/analysis-of-patients-x-ray-exposure-in-146-percutaneous-radiologic-gastrostomies
#15
Tim-Ole Petersen, Martin Reinhardt, Jochen Fuchs, Dieter Gosch, Alexey Surov, Patrick Stumpp, Thomas Kahn, Michael Moche
Purpose Analysis of patient´s X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Materials and Methods Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, and fluoroscopy time (FT) were correlated with the used x-ray systems (Flatpanel Detector (FD) vs. Image Itensifier (BV)) and the necessity for periprocedural placement of a nasogastric tube...
September 2017: RöFo: Fortschritte Auf Dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
https://www.readbyqxmd.com/read/28585520/iterative-image-domain-ring-artifact-removal-in-cone-beam-ct
#16
Xiaokun Liang, Zhicheng Zhang, Tianye Niu, Shaode Yu, Shibin Wu, Zhicheng Li, Huailing Zhang, Yaoqin Xie
Ring artifacts in cone beam computed tomography (CBCT) images are caused by pixel gain variations using flat-panel detectors, and may lead to structured non-uniformities and deterioration of image quality. The purpose of this study is to propose a method of general ring artifact removal in CBCT images. This method is based on the polar coordinate system, where the ring artifacts manifest as stripe artifacts. Using relative total variation, the CBCT images are first smoothed to generate template images with fewer image details and ring artifacts...
July 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28543761/experimental-characterization-of-a-direct-conversion-amorphous-selenium-detector-with-thicker-conversion-layer-for-dual-energy-contrast-enhanced-breast-imaging
#17
David A Scaduto, Olivier Tousignant, Wei Zhao
PURPOSE: Dual-energy contrast-enhanced imaging is being investigated as a tool to identify and localize angiogenesis in the breast, a possible indicator of malignant tumors. This imaging technique requires that x-ray images are acquired at energies above the k-shell binding energy of an appropriate radiocontrast agent. Iodinated contrast agents are commonly used for vascular imaging, and require x-ray energies greater than 33 keV. Conventional direct conversion amorphous selenium (a-Se) flat-panel imagers for digital mammography show suboptimal absorption efficiencies at these higher energies...
August 2017: Medical Physics
https://www.readbyqxmd.com/read/28529251/image-quality-and-clinical-usefulness-of-ray-summation-image-reconstructed-from-ct-data-compared-with-digital-radiography
#18
COMPARATIVE STUDY
Shogo Suzuki, Katsuhiro Ichikawa, Shigeru Tamaki
Ray-summation (raysum) images reconstructed from computed tomography (CT) volume data resemble digital radiography (DR) images. Therefore, they have a potential to be used instead of DR images.The aim of this study was to compare the physical image quality evaluated by signal-difference-to-noise ratio (SDNR) and clinical usefulness between raysum and DR images. We employed an oval water phantom simulating adult abdomen for image quality measurement. Raysum images were reconstructed from CT volume data using an assumed x-ray quality of 70 keV...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28516271/three-dimensional-image-fusion-guidance-for-transjugular-intrahepatic-portosystemic-shunt-placement
#19
Vania Tacher, Arthur Petit, Haytham Derbel, Luigi Novelli, Manuel Vitellius, Fourat Ridouani, Alain Luciani, Alain Rahmouni, Christophe Duvoux, Chady Salloum, Mélanie Chiaradia, Hicham Kobeiter
INTRODUCTION: To assess the safety, feasibility and effectiveness of image fusion guidance with pre-procedural portal phase computed tomography with intraprocedural fluoroscopy for transjugular intrahepatic portosystemic shunt (TIPS) placement. MATERIALS AND METHODS: All consecutive cirrhotic patients presenting at our interventional unit for TIPS creation from January 2015 to January 2016 were prospectively enrolled. Procedures were performed under general anesthesia in an interventional suite equipped with flat panel detector, cone-beam computed tomography (CBCT) and image fusion technique...
May 17, 2017: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/28382313/geometric-calibration-and-correction-for-a-lens-coupled-detector-in-x-ray-phase-contrast-imaging
#20
Alex George, Peter Y Chen, Alejandro Morales-Martinez, Alireza Panna, Andrew A Gomella, Eric E Bennett, Han Wen
A lens-coupled x-ray camera with a tilted phosphor collects light emission from the x-ray illuminated (front) side of phosphor. Experimentally, it has been shown to double x-ray photon capture efficiency and triple the spatial resolution along the phosphor tilt direction relative to the same detector at normal phosphor incidence. These characteristics benefit grating-based phase-contrast methods, where linear interference fringes need to be clearly resolved. However, both the shallow incident angle on the phosphor and lens aberrations of the camera cause geometric distortions...
January 2017: Journal of Medical Imaging
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