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flat panel detector

Tomoyuki Hida, Yoshitake Yamada, Masako Ueyama, Tetsuro Araki, Mizuki Nishino, Atsuko Kurosaki, Masahiro Jinzaki, Hiroshi Honda, Hiroto Hatabu, Shoji Kudoh
OBJECTIVE: To assess the diaphragmatic motion in chronic obstructive pulmonary disease (COPD) patients during forced breathing by time-resolved quantitative analysis using dynamic chest radiography and to demonstrate the characteristics and the difference from that in normal subjects. MATERIALS AND METHODS: Thirty-one COPD patients and a matched control of 31 normal subjects on age, sex, height, and weight, who underwent chest radiographs during forced breathing using dynamic chest radiography, were included in this study...
March 2019: European Journal of Radiology
Chie Kuwahara, Takatoshi Aoki, Nobuhiro Oda, Jun Kawabata, Koichiro Sugimoto, Michiko Kobayashi, Masami Fujii, Yukunori Korogi
OBJECTIVE: To investigate optimal beam quality for chest flat panel detector (FPD) system by semi-quantitatively assessment using a realistic lung phantom. MATERIALS AND METHODS: Chest FPD radiographs were obtained on a realistic lung phantom with simulated lung opacities using various X-ray tube voltage levels (90-140 kV) with/without copper filter. Entrance skin dose was set to maintain identical for all images (0.1 mGy). Three chest radiologists unaware of the exposure settings independently evaluated the image quality of each simulated opacity and normal structure using a 5-point scale (+ 2: clearly superior to the standard; + 1: slightly superior to the standard; 0: equal to the standard; - 1: slightly inferior to the standard; - 2: clearly inferior to the standard)...
February 8, 2019: European Radiology
Shinichiro Mori, Yukinobu Sakata, Ryusuke Hirai, Wataru Furuichi, Kazuki Shimabukuro, Ryosuke Kohno, Woong Sub Koom, Shigeru Kasai, Keiko Okaya, Yasushi Iseki
PURPOSE: To perform the final quality assurance of our fluoroscopic-based markerless tumor tracking for gated carbon-ion pencil beam scanning (C-PBS) radiotherapy using a rotating gantry system, we evaluated the geometrical accuracy and tumor tracking accuracy using a moving chest phantom with simulated respiration. METHODS: The positions of the dynamic flat panel detector (DFPD) and X-ray tube are subject to changes due to gantry sag. To compensate for this, we generated a geometrical calibration table (gantry flex map) in 15° gantry angle steps by the bundle adjustment method...
January 28, 2019: Medical Physics
Rie Tanaka, Tohru Tani, Norihisa Nitta, Takahisa Tabata, Noritsugu Matsutani, Shintaro Muraoka, Tsutomu Yoneyama, Shigeru Sanada
RATIONALE AND OBJECTIVES: To assess the capacity of dynamic flat-panel detector imaging without the use of contrast media to detect pulmonary embolism (PE) based on temporal changes in radiographic lung density during cardiac beating. MATERIALS AND METHODS: Sequential chest radiographs of six pigs were acquired using a dynamic flat-panel detector system. A porcine model of PE was developed, and temporal changes in pixel values in the imaged lungs were analyzed during a whole cardiac cycle...
January 22, 2019: Academic Radiology
Hideaki Tashima, Eiji Yoshida, Yuma Iwao, Hidekatsu Wakizaka, Takamasa Maeda, Chie Seki, Yasuyuki Kimura, Yuhei Takado, Makoto Higuchi, Tetsuya Suhara, Taichi Yamashita, Taiga Yamaya
A strong demand is expected for high-sensitivity, high-resolution, and low-cost brain positron emission tomography (PET) imaging for early diagnosis of dementia as well as for general neuroscience studies. Therefore, we have proposed novel geometries of a hemisphere detector arrangement for high-sensitivity brain imaging, in which an add-on detector at the chin position or neck position helps in sensitivity uniformity improvement. In this study, we developed the first prototype system for proof-of-concept using 4-layer depth-of-interaction detectors, each of which consisted of 16×16×4 Zr-doped GSO crystals with dimensions of 2...
January 23, 2019: Physics in Medicine and Biology
Reena Sharma, S D Sharma, P S Sarkar, D Datta
Introduction: Image quality of digital mammography system is generally defined by three primary physical parameters, namely, contrast, resolution, and noise. Quantification of these metrics can be done by measuring objective image quality parameters defined as contrast-to-noise ratio (CNR), modulation transfer function (MTF), and noise power spectra (NPS). Materials and Methods: In the present study, various imaging metrics such as CNR, contrast detail resolution, MTF, and NPS were evaluated for a direct flat-panel detector-based digital mammography system following the European Guidelines...
October 2018: Journal of Medical Physics
Sandra van der Velden, Britt Kunnen, Wilco J C Koppert, Johannes H L Steenbergen, Martijn M A Dietze, Casper Beijst, Max A Viergever, Marnix G E H Lam, Hugo W A M de Jong
Purpose To develop and evaluate a dual-layer detector capable of acquiring intrinsically registered real-time fluoroscopic and nuclear images in the interventional radiology suite. Materials and Methods The dual-layer detector consists of an x-ray flat panel detector placed in front of a γ camera with cone beam collimator focused at the x-ray focal spot. This design relies on the x-ray detector absorbing the majority of the x-rays while it is more transparent to the higher energy γ photons. A prototype was built and dynamic phantom images were acquired...
January 8, 2019: Radiology
S V Setlur Nagesh, V Fennel, J Krebs, C Ionita, J Davies, D R Bednarek, M Mokin, A H Siddiqui, S Rudin
BACKGROUND AND PURPOSE: Quality of visualization of treatment devices during critical stages of endovascular interventions, can directly impact their safety and efficacy. Our aim was to compare the visualization of neurointerventional procedures and treatment devices using a 194-μm pixel flat panel detector mode and a 76-μm pixel complementary metal oxide semiconductor detector mode (high definition) of a new-generation x-ray detector system using a blinded-rater study. MATERIALS AND METHODS: Deployment of flow-diversion devices for the treatment of internal carotid artery aneurysms was performed under flat panel detector and high-definition-mode image guidance in a neurointerventional phantom simulating patient cranium and tissue attenuation, embedded with 3D-printed intracranial vascular models, each with an aneurysm in the ICA segment...
December 27, 2018: AJNR. American Journal of Neuroradiology
James Anthony Seibert
Recent advances in digital detector technology for medical radiography and fluoroscopy have resulted in improved workflow efficiency, operational flexibility, image quality, and diagnostic accuracy. This is attributed to the implementation of portable flat-panel x-ray detector devices able to provide real-time readout, processing, and display of medical images. As a result, digital radiography flat-panel detectors are rapidly replacing computed radiography passive detectors for projection imaging exams and image intensifier detectors for dynamic fluoroscopy exams...
February 2019: Health Physics
Rongxiao Zhang, Gregory C Sharp, Kyung-Wook Jee, Ethan W Cascio, Joseph Mark Harms, Jacob B Flanz, Hsiao-Ming Lu
In proton therapy, range uncertainties induced by the conversion from x-ray CT (xCT) Hounsfield units (HU) to relative stopping power (RSP) compromise the precision of dose delivery. To reduce range uncertainties induced by HU-converted RSPs, this study investigates optimizing the RSP of individual voxels in xCT iteratively based on multi-projection proton radiography (pRG) acquired using a single amorphous silicon flat panel imager. Time-resolved dose rate functions (DRF) were measured by the imager placed downstream of a test phantom consisting of tissue substitute materials...
December 18, 2018: Physics in Medicine and Biology
Oliver Edwin Holmes, Janos Szanto, Vered Tsehmaister Abitbul, Taleb Al Mansoori, Hanan Al-Qahtani, John Sinclair, Daniela Iancu, Shawn Malone
Background: Successful radiosurgery for intracranial arteriovenous malformations (AVMs) requires accurate delineation of the nidus in 3D. Exact targeting and precise equipment is needed to achieve obliteration of the nidus while minimizing toxicity to the surrounding brain. In some micro-AVMs and poorly visible AVMs we have used cone beam CT angiography (CBCTA) with selective and super-selective angiography where a micro-catheter is advanced into the feeding arteries- to assist with nidus definition for CyberKnife radiosurgery planning...
2018: Journal of Radiosurgery and SBRT
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...
December 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
OBJECTIVES: Metal artefacts are highly common in dental 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, which is the first commercial dental spectral CBCT with flat-panel detector. METHODS: We carried out phantom experiments and clinical trials in this study. In the phantom study, the head phantom with metallic dental fillings and implants of various materials was scanned...
February 2019: 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
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