keyword
MENU ▼
Read by QxMD icon Read
search

Flat panel detectors

keyword
https://www.readbyqxmd.com/read/27906270/stochastic-model-for-quantum-noise-analysis-in-flat-panel-detectors-for-medical-imaging-applications
#1
Isao Yamada
A one-dimensional stochastic model is proposed to analyze the characteristics of quantum noise in flat-panel detectors (FPD) for medical imaging applications. The number of x-ray photons is modeled as a Poisson process, and explicit expressions for the autocorrelation function and noise power spectrum density (NPSD) are obtained in terms of the exposure dose, blur shape in the capture element, and pixel size. The results from the proposed model are validated with numerical simulations, and it is shown that this model can be used for the analysis of the noise properties of the FPD...
December 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/27893455/patient-radiation-doses-in-paediatric-interventional-cardiology-procedures-a-review
#2
R W Harbron, S Dreuil, M-O Bernier, M S Pearce, I Thierry-Chef, C-L Chapple, H Baysson
A large number of investigations into the radiation doses from x-ray guided interventional cardiology procedures in children have been carried out in recent years. A review was conducted of these studies, gathering data on kerma area product (P KA), fluoroscopic screening time (FT), air kerma, and estimates of effective dose and organ doses. The majority of studies focus on P KA and FT with no estimation of dose to the patient. A greater than ten-fold variation in average P KA was found between different studies, even where data were stratified by patient age or weight...
November 28, 2016: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/27886993/consideration-of-the-protection-curtain-s-shielding-ability-after-identifying-the-source-of-scattered-radiation-in-the-angiography
#3
Naoki Sato, Toshioh Fujibuchi, Takatoshi Toyoda, Takato Ishida, Hiroki Ohura, Ryuichi Miyajima, Shinichi Orita, Tomonari Sueyoshi
To decrease radiation exposure to medical staff performing angiography, the dose distribution in the angiography was calculated in room using the particle and heavy ion transport code system (PHITS), which is based on Monte Carlo code, and the source of scattered radiation was confirmed using a tungsten sheet by considering the difference shielding performance among different sheet placements. Scattered radiation generated from a flat panel detector, X-ray tube and bed was calculated using the PHITS. In this experiment, the source of scattered radiation was identified as the phantom or acrylic window attached to the X-ray tube thus, a protection curtain was placed on the bed to shield against scattered radiation at low positions...
November 24, 2016: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/27847769/clinical-utility-of-angiographic-ct-with-a-flat-detector-angiographic-system-during-endovascular-procedure
#4
Seon Woong Choi, Kwang Wook Jo, Young Woo Kim, Seong Rim Kim, Ik Seong Park, Hoon Kim
OBJECTIVE: We evaluated the feasibility of angiographic computed tomography (ACT) for visualizing stent material in patients who underwent intracranial or extracranial stent placement to treat atherosclerotic lesions or stent assisted coil embolization. MATERIALS AND METHODS: We performed intrarterial and intravenous ACT on biplane angiography system equipped with flat panel detectors (Axiom Arits dBA; Siemens Medical Solutions, Forchheim, Germany). Vistipaque 320 was injected for contrast medium, total 150 mL at flow rate of 5 mL/s through artery and 77 mL at flow rate of 3...
September 2016: Journal of Cerebrovascular and Endovascular Neurosurgery
https://www.readbyqxmd.com/read/27806621/a-method-for-geometric-calibration-of-edge-on-detectors-in-a-ct-gantry
#5
Martin Sjölin, Mats Danielsson
PURPOSE: Photon-counting edge-on detectors are currently being considered for use in clinical computed tomography (CT) systems. A method for geometric calibration of edge-on detectors mounted on a CT-gantry has been developed and evaluated. The method is complementary to the geometrical calibration methods developed for CT systems using flat-panel detectors and takes the extra dimension of the edge-on detectors (along the direction of the x-rays) into account. METHODS: The method uses projection images of a simple phantom together with geometrical arguments to accurately estimate the orientation and relative position of the edge-on detectors...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27806106/voxel-based-sensitivity-of-flat-panel-ct-for-the-detection-of-intracranial-hemorrhage-comparison-to-multi-detector-ct
#6
Andreas M Frölich, Jan-Hendrik Buhk, Jens Fiehler, Andre Kemmling
OBJECTIVES: Flat-panel CT (FPCT) allows cross-sectional parenchymal, vascular and perfusion imaging within the angiography suite, which could greatly facilitate acute stroke management. We hypothesized that FPCT offers equal diagnostic accuracy compared to multi-detector CT (MDCT) as a primary tool to exclude intracranial hemorrhage. METHODS: 22 patients with intracranial hematomas who had both MDCT and FPCT performed within 24 hours were retrospectively identified...
2016: PloS One
https://www.readbyqxmd.com/read/27804925/multiple-energy-synchrotron-biomedical-imaging-system
#7
B Bassey, M Martinson, N Samadi, G Belev, C Karanfil, P Qi, D Chapman
A multiple energy imaging system that can extract multiple endogenous or induced contrast materials as well as water and bone images would be ideal for imaging of biological subjects. The continuous spectrum available from synchrotron light facilities provides a nearly perfect source for multiple energy x-ray imaging. A novel multiple energy x-ray imaging system, which prepares a horizontally focused polychromatic x-ray beam, has been developed at the BioMedical Imaging and Therapy bend magnet beamline at the Canadian Light Source...
November 2, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27801658/radiation-exposure-and-contrast-agent-reduction-during-transcatheter-aortic-valve-implantation-an-ongoing-experience
#8
Davide Maccagni, Cosmo Godino, Azeem Latib, Morena Mancin, Alaide Chieffo, Alberto Margonato, Antonio Colombo
OBJECTIVES: To determine the patient radiation exposure and contrast agent variation during transcatheter aortic valve implantation (TAVI) procedures resulting from technological improvements. METHODS: TAVI procedures from January 2008 to July 2015 were analyzed in three different time periods: 1st period, when the angiography was equipped with an image intensifier technology; 2nd period, starting with the installation of a new angiography system with flat-panel detector (FPD) technology; and 3rd period, starting with the systematic use of preprocedural multidetector computed tomography (MDCT) to individualize optimal fluoroscopic projections for the aortic prosthesis implantation...
November 2016: Journal of Invasive Cardiology
https://www.readbyqxmd.com/read/27782694/technical-assessment-of-a-prototype-cone-beam-ct-system-for-imaging-of-acute-intracranial-hemorrhage
#9
Jennifer Xu, Alejandro Sisniega, Wojciech Zbijewski, Hao Dang, J Webster Stayman, Michael Mow, Xiaohui Wang, David H Foos, Vassillis E Koliatsos, Nafi Aygun, Jeffrey H Siewerdsen
PURPOSE: A cone-beam CT scanner has been developed for detection and monitoring of traumatic brain injury and acute intracranial hemorrhage (ICH) at the point of care. This work presents a technical assessment of imaging performance and dose for the scanner in phantom and cadaver studies as a prerequisite to clinical translation. METHODS: The scanner incorporates a compact, rotating-anode x-ray source and a flat-panel detector (43 × 43 cm(2)) on a mobile U-arm gantry with source-axis distance = 550 mm and source-detector distance = 1000 mm...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27782684/technical-note-an-oversampling-procedure-to-calculate-the-mtf-of-an-imaging-system-from-a-bar-pattern-image
#10
Antonio González-López, Pedro Antonio Campos-Morcillo, José Domingo Lago-Martín
PURPOSE: Line-pair resolution phantoms are used to determine the spatial resolution of medical imaging systems. In some cases, these phantoms are used to determine the maximum number of line-pairs per mm that the system can resolve. In other cases, a numerical determination of the modulation transfer function (MTF) is carried out by means of the analysis of the variance of ROIs on the image. In this note, a new procedure is implemented to calculate the presampled MTF of an imaging system...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27779141/development-and-first-use-of-a-novel-cylindrical-ball-bearing-phantom-for-9-dof-geometric-calibrations-of-flat-panel-imaging-devices-used-in-image-guided-ion-beam-therapy
#11
A Zechner, M Stock, D Kellner, I Ziegler, P Keuschnigg, P Huber, U Mayer, F Sedlmayer, H Deutschmann, P Steininger
Image guidance during highly conformal radiotherapy requires accurate geometric calibration of the moving components of the imager. Due to limited manufacturing accuracy and gravity-induced flex, an x-ray imager's deviation from the nominal geometrical definition has to be corrected for. For this purpose a ball bearing phantom applicable for nine degrees of freedom (9-DOF) calibration of a novel cone-beam computed tomography (CBCT) scanner was designed and validated. In order to ensure accurate automated marker detection, as many uniformly distributed markers as possible should be used with a minimum projected inter-marker distance of 10 mm...
November 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27754987/npwe-model-observer-as-a-validated-alternative-for-contrast-detail-analysis-of-digital-detectors-in-general-radiography
#12
N Van Peteghem, H Bosmans, N W Marshall
To propose and validate a non-prewhitening with eye filter (NPWE) model observer as an alternative means of quantifying and specifying imaging performance for general radiography detectors, in a comparative study with contrast detail analysis and detective quantum efficiency (DQE). Five different x-ray detectors were assessed, covering a range of detector technologies including powder computed radiography (CR), needle CR, and three indirect conversion flat panel digital radiography detectors (DR). For each detector, threshold contrast detail (c-d) detectability was measured using the Leeds TO20 test object...
November 7, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27727117/cone-beam-micro-computed-tomography-dedicated-to-the-breast
#13
Antonio Sarno, Giovanni Mettivier, Francesca Di Lillo, Mario Cesarelli, Paolo Bifulco, Paolo Russo
We developed a scanner for micro computed tomography dedicated to the breast (BµCT) with a high resolution flat-panel detector and a microfocus X-ray tube. We evaluated the system spatial resolution via the 3D modulation transfer function (MTF). In addition to conventional absorption-based X-ray imaging, such a prototype showed capabilities for propagation-based phase-contrast and related edge enhancement effects in 3D imaging. The system limiting spatial resolution is 6.2mm(-1) (MTF at 10%) in the vertical direction and 3...
October 7, 2016: Medical Engineering & Physics
https://www.readbyqxmd.com/read/27716681/separable-scatter-model-of-the-detector-and%C3%A2-object-contributions-using-continuously-thickness-adapted-kernels-in-cbct
#14
Navnina Bhatia, David Tisseur, Solene Valton, Jean Michel Létang
Due to the increased cone beam coverage and the introduction of flat panel detector, the size of X-ray illumination fields has grown dramatically in Cone Beam Computed Tomography (CBCT), causing an increase in scatter radiation. Existing reconstruction algorithms do not model the scatter radiation, so scatter artifacts appear in the reconstruction images. The contribution of scattering of photons inside the detector itself becomes prominent and challenging in case of X-ray source of high energy (over a few 100 keV) which is used in typical industrial Non Destructive Testing (NDT)...
October 6, 2016: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/27680419/noise-power-characteristics-of-a-micro-computed-tomography-system
#15
Muhammad U Ghani, Liqiang Ren, Molly Wong, Yuhua Li, Bin Zheng, Xiujiang John Rong, Kai Yang, Hong Liu
OBJECTIVE: The aim of this study was to investigate the noise power properties of a micro-computed tomography (micro-CT) system under different operating conditions. METHODS: A commercial micro-CT was used in the study that used a flat panel detector with a 127-μm-pixel pitch and a micro-focus x-ray tube. Conical tubes of various diameters were used under different acquisition conditions. Multidimensional noise power spectrums were used as a metric to investigate the noise properties of the system...
September 27, 2016: Journal of Computer Assisted Tomography
https://www.readbyqxmd.com/read/27668790/flat-panel-ct-for-cochlear-implant-electrode-imaging-comparison-to-multi-detector-ct
#16
Tabassum A Kennedy, Nathan Connell, Timothy Szczykutowicz, Sebastian Schafer, Kevin Royalty, Sara Nace, Brian Gartrell, Samuel Gubbels
HYPOTHESIS: Flat-panel computed tomography (FPCT) will allow more accurate localization of cochlear implants with decreased metallic artifact and decreased radiation dose when compared with multi-detector CT (MDCT). BACKGROUND: The measurement of scalar location and intra-scalar position of cochlear implantation (CI) electrodes using computed tomography (CT) is complicated by metallic image artifact and insufficient scalar resolution. FPCT has been shown to improve upon the resolution of MDCT while reducing artifact...
September 23, 2016: Otology & Neurotology
https://www.readbyqxmd.com/read/27664432/optimisation-of-patient-dose-and-image-quality-in-endoscopic-retrograde-cholangiopancreatography-a-phantom-based-evaluation
#17
Anastasia C Hadjiconstanti, Gerasimos A T Messaris, Konstantinos C Thomopoulos, Aikaterini G Solomou, George S Panayiotakis
A phantom-based study is presented aiming to optimise patient dose and image quality (IQ) in endoscopic retrograde cholangiopancreatography procedures, utilising a fluoroscopy system equipped with a flat panel detector. The patient thickness was simulated with various polymethyl methacrylate slabs, whilst IQ was evaluated using the Leeds test object. The main factors evaluated were phantom thickness, distance between phantom and detector, field of view and pulse rate. For all these factors, the dosemetric indices, entrance surface air kerma (ESAK) rate and ESAK per pulse, as well as the IQ parameters, signal-to-noise ratio and high contrast spatial resolution, were measured...
September 24, 2016: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/27646696/-intraoperative-3d-imaging-in-spinal-surgery
#18
O Gonschorek, S Hauck, V Bühren
BACKGROUND: Intraoperative imaging during spinal interventions has experienced significant developments over the last two decades. By the introduction of flat screen detectors, 3D imaging has been made possible and easier and by developing compact and mobile systems computed tomography can even be used in the operating theater. OBJECTIVE: Presentation of modern intraoperative 3D imaging and navigation in spinal surgery. MATERIAL AND METHODS: The techniques of intraoperative 3D imaging and navigation during spinal procedures are presented based on the currently available literature and own experiences at a German national spine and trauma center...
October 2016: Der Unfallchirurg
https://www.readbyqxmd.com/read/27613643/diaphragm-height-varies-with-arm-position-comparison-between-angiography-and-ct
#19
Shiro Onozawa, Satoru Murata, Takayoshi Kimura, Tatsuo Ueda, Fumie Sugihara, Daisuke Yasui, Hiroyuki Tajima
PURPOSE: To investigate how elevation of the arms affects diaphragm height. MATERIALS AND METHODS: We retrospectively reviewed angiography and computed tomography (CT) portography data from 44 patients who were treated for hepatocellular carcinoma at our institution from July 2013 to May 2014. Diaphragm height was determined independently by two radiologists as the distance from the upper edge of the first lumbar vertebra to the highest point of the right diaphragm...
September 9, 2016: Japanese Journal of Radiology
https://www.readbyqxmd.com/read/27562478/radiation-doses-to-operators-performing-transjugular-intrahepatic-portosystemic-shunt-using-a-flat-panel-detector-based-system-and-ultrasound-guidance-for-portal-vein-targeting
#20
Roberto Miraglia, Roberta Gerasia, Luigi Maruzzelli, Mario D'Amico, Angelo Luca
OBJECTIVES: The aim of this study was to prospectively evaluate effective dose (E) of operators performing transjugular intrahepatic portosystemic shunts (TIPS) in a single centre. Patients' radiation exposure was also collected. METHODS: Between 8/2015 and 6/2016, 45 consecutive TIPS were performed in adult patients using a flat-panel detector-based system (FPDS) and real-time ultrasound guidance (USG) for portal vein targeting. Electronic personal dosimeters were used to measure radiation doses to the primary and assistant operators, anaesthesia nurse and radiographer...
August 25, 2016: European Radiology
keyword
keyword
1339
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"