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Flat panel detectors

Alisa I Walz-Flannigan, Kimberly J Brossoit, Dayne J Magnuson, Beth A Schueler
Visual familiarity with the variety of digital radiographic artifacts is needed to identify, resolve, or prevent image artifacts from creating issues with patient imaging. Because the mechanism for image creation is different between flat-panel detectors and computed radiography, the causes and appearances of some artifacts can be unique to these different modalities. Examples are provided of artifacts that were found on clinical images or during quality control testing with flat-panel detectors. The examples are meant to serve as learning tools for future identification and troubleshooting of artifacts and as a reminder for steps that can be taken for prevention...
April 20, 2018: Radiographics: a Review Publication of the Radiological Society of North America, Inc
Masayuki Kumashiro, Takahiro Kataoka, Shinobu Yokota, Shinobu Nakagawa, Keisuke Otsuki, Nobuyuki Miyake, Shinji Osumi, Kiyonori Yamaoka
We examined the effects of a reduced exposure dose on the quality of images from an angiography device augmented with a noise reduction algorithm. Before its clinical application, we compared the diameter of the discrimination limit of the hole with that in the conventional method by a visual evaluation with a contrast-detail (C-D) phantom imaged using the target dose. Based on the results, a reducible dose was determined and applied clinically. The sample population consisted of patients being followed up after percutaneous coronary intervention (PCI) for coronary artery disease; we evaluated the effects of the exposure reduction on image quality...
April 2018: Acta Medica Okayama
Arianna Ferrari, Luca Bertolaccini, Piergiorgio Solli, Paola Oriana Di Salvia, David Scaradozzi
Lung cancer is the leading cause of cancer death and second most common cancer among both men and women, but most of them are detected when patients become symptomatic and in late-stage. Chest radiography (CR) is a basic technique for the investigation of lung cancer and has the benefit of convenience and low radiation dose, but detection of malignancy is often difficult. The introduction of computed tomography (CT) for screening has increased the proportion of lung cancer detected but with higher exposure dose and higher costs...
March 2018: Annals of Translational Medicine
Jason F Talbott, Daniel L Cooke, Marc C Mabray, Paul S Larson, Matthew R Amans, Steven W Hetts, Mark W Wilson, Terilyn Moore, Ernesto A Salegio
PURPOSE: To evaluate the accuracy of percutaneous fluoroscopic injection into the spinal cord of a spine phantom utilizing integrated navigational guidance from fused flat panel detector CT (FDCT) and MR datasets. Conventional and convection-enhanced delivery (CED) techniques were evaluated. MATERIALS AND METHODS: FDCT and MR datasets of a swine thoracic spine phantom were co-registered using an integrated guidance system and surface to spinal cord target trajectory planning was performed on the fused images...
April 17, 2018: Journal of Neurointerventional Surgery
Christian A Bohoun, Kentaro Naito, Toru Yamagata, Samantha Tamrakar, Kenji Ohata, Toshihiro Takami
Although spinal instrumentation technique has undergone revolutionary progress over the past few decades, it may still carry significant surgery-related risks. The purpose of the present study was to assess the radiological accuracy of spinal screw instrumentation using a hybrid operating room (OR) and quantify the related radiation exposure. This retrospective study included 33 cases of complex spine fusion surgeries that were conducted using a hybrid OR with a flat panel detector (FPD) angiography system...
April 16, 2018: Neurosurgical Review
Juliaan R M van Rappard, Willy A Hummel, Tijmen de Jong, Chantal M Mouës
BACKGROUND: The use of intraoperative fluoroscopy has become mandatory in osseous hand surgery. Due to its overall practicality, the mini C-arm has gained popularity among hand surgeons over the standard C-arm. This study compares image quality and radiation exposure for patient and staff between the mini C-arm and the standard C-arm, both with flat panel technology. METHODS: An observer-based subjective image quality study was performed using a contrast detail (CD) phantom...
April 1, 2018: Hand: Official Journal of the American Association for Hand Surgery
Dong Sik Kim, Eunae Lee
Fixed pattern noise due to nonuniform amplifier gains and scintillator sensitivity should be alleviated in radiography imaging to acquire low-noise x-ray images from detectors. Here, the noise property of the detector is usually evaluated observing the noise power spectrum (NPS). A gain-correction scheme, in which uniformly illuminated images are averaged to design a gain map, can be applied to alleviate the fixed pattern noise problem. The normalized NPS (NNPS) of the gain-corrected image decreases as the number of images for the average increases and converges to an infimum, which can be achieved if the fixed pattern noise is completely removed...
January 2018: Journal of Medical Imaging
Koji Murakami, Satoshi Hamai, Ken Okazaki, Yifeng Wang, Satoru Ikebe, Hidehiko Higaki, Takeshi Shimoto, Hideki Mizu-Uchi, Yukio Akasaki, Yasuharu Nakashima
PURPOSE: This study aimed to evaluate the effects of two types of total knee arthroplasty (TKA) designs: posterior-stabilized (PS) and bicruciate-stabilized (BCS) on in vivo kinematics during gait. METHODS: Continuous X-ray images of the gait were taken using a flat panel detector for 23 PS and BCS TKAs. We analyzed the tibiofemoral implant flexion angle, anteroposterior (AP) translation, axial rotation, and anterior/posterior cam-post contact using image-matching techniques...
April 5, 2018: International Orthopaedics
Ioannis A Tsalafoutas
OBJECTIVE: To investigate whether electronic collimation software, which is available in all digital X-ray systems, may comprise an overexposure risk. METHODS: In the context of surveys on Diagnostic Reference Levels carried out in two radiographic facilities, along with data on exposure factors, the radiographic field sizes were also recorded. In one facility (Unit A), a wireless flat panel detector is used with a conventional X-ray unit, while in the other, a fully digital system is installed (Unit B)...
March 22, 2018: British Journal of Radiology
Adam Wang, Alexander Maslowski, Philippe Messmer, Mathias Lehmann, Adam Strzelecki, Elaine Yu, Pascal Paysan, Marcus Brehm, Peter Munro, Josh Star-Lack, Dieter Seghers
PURPOSE: To correct for scatter in kV cone-beam CT (CBCT) projection data on a clinical system using a new tool, Acuros® CTS, that estimates scatter images rapidly and accurately by deterministically solving the linear Boltzmann transport equation. METHODS: Phantom and patient CBCT scans were acquired on TrueBeam® radiotherapy machines. A first-pass reconstruction was used to create water and bone density maps of the imaged object, which was updated to include a more accurate representation of the patient couch...
March 6, 2018: Medical Physics
Rie Tanaka, Tohru Tani, Norihisa Nitta, Takahisa Tabata, Noritsugu Matsutani, Shintaro Muraoka, Tsutomu Yoneyama, Shigeru Sanada
OBJECTIVES: The aims of this study were to address the relationship between respiratory changes in image density of the lungs and tidal volume, to compare the changes between affected and unaffected lobes, and to apply this new technique to the diagnosis of atelectasis. MATERIALS AND METHODS: Our animal care committee approved this prospective animal study. Sequential chest radiographs of 4 pigs were obtained under respiratory control with a ventilator using a dynamic flat-panel detector system...
March 2, 2018: Investigative Radiology
A Sonig, S V Setlur Nagesh, V S Fennell, S Gandhi, L Rangel-Castilla, C N Ionita, K V Snyder, L N Hopkins, D R Bednarek, S Rudin, A H Siddiqui, E I Levy
BACKGROUND AND PURPOSE: The ROI-dose-reduced intervention technique represents an extension of ROI fluoroscopy combining x-ray entrance skin dose reduction with spatially different recursive temporal filtering to reduce excessive image noise in the dose-reduced periphery in real-time. The aim of our study was to compare the image quality of simulated neurointerventions with regular and reduced radiation doses using a standard flat panel detector system. MATERIALS AND METHODS: Ten 3D-printed intracranial aneurysm models were generated on the basis of a single patient vasculature derived from intracranial DSA and CTA...
February 15, 2018: AJNR. American Journal of Neuroradiology
Sangeetha Jayakumar, T Saravanan, John Philip
Nanocomposites containing α-Bi2O3, β-Bi2O3 and Bi nanoparticles as nanofillers in vulcanized silicone resin as a matrix are prepared and their diagnostic X-ray attenuation property is studied. The nanocomposites are prepared using a simple solution casting technique, with nanofiller concentration varying from 2-50 wt%. Thermogravimetric analysis and differential scanning calorimetry are performed to study the thermal stability of the nanocomposites. The attenuation property is studied by exposing the nanocomposites containing α-Bi2O3, β-Bi2O3 and Bi nanoparticles to X-rays of energy 30-60 keV...
June 1, 2018: Journal of Nanoscience and Nanotechnology
Yoshinori Miyahara, Yuki Hara, Hiroto Nakashima, Tomonori Nishimura, Kanae Itakura, Taisuke Inomata, Hajime Kitagaki
In high-dose-rate (HDR) brachytherapy, a direct-conversion flat-panel detector (d-FPD) clearly depicts a 192Ir source without image halation, even under the emission of high-energy gamma-rays. However, it has been unknown why iridium is visible using a d-FPD. The purpose of this study was to clarify reasons for visibility of the source core based on physical imaging characteristics, including the modulation transfer functions (MTF), noise power spectral (NPS), contrast transfer functions (CTF), and linearity of d-FPD to high-energy gamma-rays...
February 9, 2018: Physics in Medicine and Biology
Raymond R Raylman, Will Van Kampen, Alexander V Stolin, Wenbo Gong, Gangadhar Jaliparthi, Peter F Martone, Mark F Smith, David Sarment, Neal H Clinthorne, Mark Perna
PURPOSE: Application of advanced imaging techniques, such as PET and x ray CT, can potentially improve detection of breast cancer. Unfortunately, both modalities have challenges in the detection of some lesions. The combination of the two techniques, however, could potentially lead to an overall improvement in diagnostic breast imaging. The purpose of this investigation is to test the basic performance of a new dedicated breast-PET/CT. METHODS: The PET component consists of a rotating pair of detectors...
February 1, 2018: Medical Physics
M Ohtani, T Oshima, S Mimasaka
BACKGROUND: Forensic odontologists commonly incise the skin for post-mortem dental examinations when it is difficult to open the victim's mouth. However, it is prohibited by law to incise dead bodies without permission in Japan. Therefore, we attempted using extra-oral dental radiography, using a digital X-ray equipment with rechargeable batteries, to overcome this restriction. MATERIALS AND METHODS: A phantom was placed in the prone position on a table, and three plain dental radiographs were used per case: "lateral oblique radiographs" for left and right posterior teeth and a "contact radiograph" for anterior teeth were taken using a flat panel X-ray detector and a hand-held X-ray generator...
December 1, 2017: Journal of Forensic Odonto-stomatology
Chenyang Qiu, Jiang Shao, Xiu Liu, Bao Liu
RATIONALE: Traditional digital subtraction angiography (DSA) provides lumen morphology of renal artery as indicators for vascular patency in patients with renal artery stenosis (RAS). It, however, lacks hemodynamic information toward target kidney. To solve this shortcoming, a novel technique, flat-panel detector parenchymal blood volume imaging (FD-PBV), is introduced, which is able to evaluate hemodynamic changes of target kidney intraoperatively. PATIENTS CONCERNS: A 77-year-old female presented with hypertension, intermittent dizziness, nausea, and fatigue...
November 2017: Medicine (Baltimore)
Yohei Takeshita, Mayumi Shimizu, Gainer R Jasa, Warangkana Weerawanich, Kazutoshi Okamura, Shoko Yoshida, Kenji Tokumori, Junichi Asaumi, Kazunori Yoshiura
OBJECTIVES: To compare the results of a new quantitative image quality evaluation method that requires no observers with the results of receiver operating characteristic (ROC) analysis in detecting the mandibular canal in cone beam CT (CBCT) images. METHODS: A Teflon (polytetrafluoroethylene) plate phantom with holes of different depths was scanned with two CBCT systems. One CBCT system was equipped with an image intensifier (Experiment 1), and the other was equipped with a flat panel detector (Experiment 2)...
January 29, 2018: Dento Maxillo Facial Radiology
Gage Redler, Kevin C Jones, Alistair Templeton, Damian Bernard, Julius Turian, James C H Chu
PURPOSE: Lung stereotactic body radiation therapy (SBRT) requires delivering large radiation doses with millimeter accuracy, making image guidance essential. An approach to forming images of patient anatomy from Compton-scattered photons during lung SBRT is presented. METHODS: To investigate the potential of scatter imaging, a pinhole collimator and flat-panel detector are used for spatial localization and detection of photons scattered during external beam therapy using lung SBRT treatment conditions (6 MV FFF beam)...
March 2018: Medical Physics
Bente Thamsen, Mathieu Plamondon, Marcus Granegger, Marianne Schmid Daners, Rolf Kaufmann, Antonia Neels, Mirko Meboldt
The HeartWare HVAD is a radial rotary blood pump with a combination of passive magnetic and hydrodynamic bearings to levitate the impeller. The axial gap size between impeller and housing in this bearing and its sensitivity to speed, flow, and pressure difference is difficult to assess. Shear stresses are exceptionally high in this tiny gap making it important for blood damage and related adverse events. Therefore, the aim of this study was to measure the axial gap clearance in the HVAD at different operating conditions employing radiography...
January 17, 2018: Artificial Organs
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