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Sample records for flat-panel-detector chest radiography

  1. Digital chest radiography: flat-panel detectors or conventional radiographs

    International Nuclear Information System (INIS)

    Schaefer-Prokop, C.; Uffmann, M.; Sailer, J.; Kabalan, N.; Herold, C.; Prokop, M.

    2003-01-01

    Flat panel detectors are characterized by improved handling and increased dose efficiency. This allows for increasing of work flow efficiency and for reducing the exposure dose by about 50% compared to current systems with a sensitivity of 400. Whether the increased dose efficiency should be used to reduce acquisition dose or to increase image quality in the chest, will be shown by further clinical experience and will be also determined by the subjective preference of the radiologists. The decreased level of image noise opens new perspectives for image processing that way that elaborated multifrequency processing allows for optimizing the display of very small and low contrast structures that was so far limited by overlying image noise. Specialized applications of dual energy subtraction and temporal subtraction will also profit by the new detector technology and will be further driven forward in context with applications such as computed assisted diagnosis even though this is currently not yet broadly applied. Storage phosphor radiography still represents an important alternative technique based on its larger flexibility with respect to equipment configuration, its broader application options in intensive care and emergency radiology and due to economic reasons. These facts are further underlined by the fact that image quality also in storage phosphor radiography could be constantly increased by improving detector technology and image processing and consequently has a high standard. (orig.) [de

  2. Dynamic chest radiography: flat-panel detector (FPD) based functional X-ray imaging.

    Science.gov (United States)

    Tanaka, Rie

    2016-07-01

    Dynamic chest radiography is a flat-panel detector (FPD)-based functional X-ray imaging, which is performed as an additional examination in chest radiography. The large field of view (FOV) of FPDs permits real-time observation of the entire lungs and simultaneous right-and-left evaluation of diaphragm kinetics. Most importantly, dynamic chest radiography provides pulmonary ventilation and circulation findings as slight changes in pixel value even without the use of contrast media; the interpretation is challenging and crucial for a better understanding of pulmonary function. The basic concept was proposed in the 1980s; however, it was not realized until the 2010s because of technical limitations. Dynamic FPDs and advanced digital image processing played a key role for clinical application of dynamic chest radiography. Pulmonary ventilation and circulation can be quantified and visualized for the diagnosis of pulmonary diseases. Dynamic chest radiography can be deployed as a simple and rapid means of functional imaging in both routine and emergency medicine. Here, we focus on the evaluation of pulmonary ventilation and circulation. This review article describes the basic mechanism of imaging findings according to pulmonary/circulation physiology, followed by imaging procedures, analysis method, and diagnostic performance of dynamic chest radiography.

  3. Digital chest radiography with an amorphous silicon flat-panel-detector versus a storage-phosphor system: comparison of soft-copy images

    International Nuclear Information System (INIS)

    Lee, Hyun Ju; Im, Jung Gi; Goo, Jin Mo; Lee, Chang Hyun

    2006-01-01

    We compared the soft-copy images produced by an amorphous silicon flat-panel-detector system with the images produced by a storage-phosphor radiography system for their ability to visualize anatomic regions of the chest. Two chest radiologists independently analyzed 234 posteroanterior chest radiographs obtained from 78 patients on high-resolution liquid crystal display monitors (2560 x 2048 x 8 bits). In each patient, one radiograph was obtained with a storage-phosphor system, and two radiographs were obtained via amorphous silicon flat-panel-detector radiography with and without spatial frequency filtering. After randomizing the 234 images, the interpreters rated the visibility and radiographic quality of 11 different anatomic regions. Each image was ranked on a five-point scale (1 = not visualized, 2 = poor visualization, 3 = fair visualization, 4 = good visualization, and 5 = excellent visualization). The statistical difference between each system was determined using the Wilcoxon's signed rank test. The visibility of three anatomic regions (hilum, heart border and ribs), as determined by the chest radiologist with 14 years experience (ρ < 0.05) and the visibility of the thoracic spine, as determined by the chest radiologist with 8 years experience (ρ = 0.036), on the amorphous silicon flat-panel-detector radiography prior to spatial frequency filtering were significantly superior to that on the storage-phosphor radiography. The visibility of 11 anatomic regions, as determined by the chest radiologist with 14 years experience (ρ < 0.0001) and the visibility of five anatomic regions (unobscured lung, rib, proximal airway, thoracic spine and overall appearance), as determined by the chest radiologist with 8 years experience (ρ < 0.05), on the amorphous silicon flat-panel-detector radiography after spatial frequency filtering were significantly superior to that on the storage-phosphor radiography. The amorphous silicon flat-panel-detector system depicted the

  4. Optimization of dual-energy subtraction chest radiography by use of a direct-conversion flat-panel detector system.

    Science.gov (United States)

    Fukao, Mari; Kawamoto, Kiyosumi; Matsuzawa, Hiroaki; Honda, Osamu; Iwaki, Takeshi; Doi, Tsukasa

    2015-01-01

    We aimed to optimize the exposure conditions in the acquisition of soft-tissue images using dual-energy subtraction chest radiography with a direct-conversion flat-panel detector system. Two separate chest images were acquired at high- and low-energy exposures with standard or thick chest phantoms. The high-energy exposure was fixed at 120 kVp with the use of an auto-exposure control technique. For the low-energy exposure, the tube voltages and entrance surface doses ranged 40-80 kVp and 20-100 % of the dose required for high-energy exposure, respectively. Further, a repetitive processing algorithm was used for reduction of the image noise generated by the subtraction process. Seven radiology technicians ranked soft-tissue images, and these results were analyzed using the normalized-rank method. Images acquired at 60 kVp were of acceptable quality regardless of the entrance surface dose and phantom size. Using a repetitive processing algorithm, the minimum acceptable doses were reduced from 75 to 40 % for the standard phantom and to 50 % for the thick phantom. We determined that the optimum low-energy exposure was 60 kVp at 50 % of the dose required for the high-energy exposure. This allowed the simultaneous acquisition of standard radiographs and soft-tissue images at 1.5 times the dose required for a standard radiograph, which is significantly lower than the values reported previously.

  5. Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography

    International Nuclear Information System (INIS)

    Oda, S.; Awai, K.; Funama, Y.; Utsunomiya, D.; Yanaga, Y.; Kawanaka, K.; Nakaura, T.; Hirai, T.; Murakami, R.; Nomori, H.; Yamashita, Y.

    2010-01-01

    Aim: To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs. Materials and methods: Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring ≤20 mm and from 15 normal participants. Each dataset included standard and corresponding DES images. There were six non-solid, 10 part-solid, and 10 solid nodules. The mean size of the 26 nodules was 15 ± 4.8 mm. Receiver operating characteristic (ROC) analysis was performed to compare the performance of the eight board-certified radiologists. Results: For the eight radiologists, the mean value of the area under the ROC curve (AUC) without and with DES images was 0.62 ± 0.05 and 0.68 ± 0.05, respectively; the difference was statistically significant (p = 0.02). For part-solid nodules, the difference of the mean AUC value was statistically significant (AUC = 0.61 ± 0.07 versus 0.69 ± 0.05; p < 0.01); for non-solid nodules it was not (AUC = 0.62 ± 0.1 versus 0.61 ± 0.09; p = 0.73), and for solid nodules it was not (AUC = 0.75 ± 0.1 versus 0.78 ± 0.08; p = 0.23). For nodules with overlapping bone shadows, the difference of the mean AUC value was statistically significant (p = 0.03), for nodules without overlapping, it was not (p = 0.26). Conclusion: Use of a double-exposure DES technique at FPD chest radiography significantly improved the diagnostic performance of radiologists to detect small pulmonary nodules.

  6. Digital radiography with large-area flat-panel detectors

    International Nuclear Information System (INIS)

    Kotter, E.; Langer, M.

    2002-01-01

    Large-area flat-panel detectors with active readout mechanisms have been on the market for the past 2 years. This article describes different detector technologies. An important distinction is made between detectors with direct and those with indirect conversion of X-rays into electrical charges. Detectors with indirect conversion are built with unstructured or structured scintillators, the latter resulting in less lateral diffusion of emitted light. Some important qualities of flat-panel detectors are discussed. The first phantom and clinical studies published report an image quality at least comparable to that of screen-film systems and a potential for dose reduction. The available studies are summarised in this article. (orig.)

  7. Flat panel detectors - closing the (digital) gap in chest and skeletal radiology

    International Nuclear Information System (INIS)

    Reiff, Kurt J.

    1999-01-01

    In the radiological department today the majority of all X-ray procedures on chest and skeletal radiography is performed with classical film-screen-systems. Using digital luminescence radiography (DLR or CR, which stands for Computed Radiography) as a technique has shown a way to replace this 100-year-old procedure of doing general radiography work by acquiring the X-rays digitally via phosphor screens, but this approach has faced criticism from lots of radiologists world wide and therefore has not been widely accepted except in the intensive care environment. A new technology is now rising based on the use of so called flat panel X-ray (FD) detectors. Semi-conducting material detects the X-rays in digital form directly and creates an instantaneous image for display, distribution and diagnosis. This ability combined with a large field of view and -- compared to existing methods -- excellent detective quantum efficiency represents a revolutionary step for chest and skeletal radiography and will put basic X-ray-work back into the focus of radiological solutions. This paper will explain the basic technology of flat panel detectors, possible system solutions based on this new technology, aspects of the user interface influencing the system utilization and versatility as well as the possibility to redefine the patient examination process for chest and skeletal radiography. Furthermore the author discusses limitations for the first released systems, upgrades for the installed base and possible scenarios for the future. e.g. fluoroscopy or angiography application

  8. Difference in diaphragmatic motion during tidal breathing in a standing position between COPD patients and normal subjects: Time-resolved quantitative evaluation using dynamic chest radiography with flat panel detector system (“dynamic X-ray phrenicography”)

    International Nuclear Information System (INIS)

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto

    2017-01-01

    Highlights: • Dynamic X-ray phrenicography is a useful method for the evaluation of the diaphragms. • Its radiation dose is comparable to conventional two projection chest radiography. • Diaphragm motion during tidal breathing is larger in COPD than in normal subjects. • Higher BMI is also associated with increased excursions of the bilateral diaphragm. - Abstract: Objectives: To quantitatively compare diaphragmatic motion during tidal breathing in a standing position between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography. Materials and methods: Thirty-nine COPD patients (35 males; age, 71.3 ± 8.4 years) and 47 normal subjects (non-smoker healthy volunteers) (20 males; age, 54.8 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions and peak motion speeds of the diaphragms. The results were analyzed using an unpaired t-test and a multiple linear regression model. Results: The excursions of the diaphragms in COPD patients were significantly larger than those in normal subjects (right, 14.7 ± 5.5 mm vs. 10.2 ± 3.7 mm, respectively, P < 0.001; left, 17.2 ± 4.9 mm vs. 14.9 ± 4.2 mm, respectively, P = 0.022). Peak motion speeds in inspiratory phase were significantly faster in COPD patients compared to normal subjects (right, 16.3 ± 5.0 mm/s vs. 11.8 ± 4.2 mm/s, respectively, P < 0.001; left, 18.9 ± 4.9 mm/s vs. 16.7 ± 4.0 mm/s, respectively, P = 0.022). The multivariate analysis demonstrated that having COPD and higher body mass index were independently associated with increased excursions of the bilateral diaphragm (all P < 0.05), after adjusting for other clinical variables. Conclusions: Time-resolved quantitative evaluation of the diaphragm using dynamic chest radiography demonstrated that the diaphragmatic motion during tidal breathing in a standing position is larger and

  9. Difference in diaphragmatic motion during tidal breathing in a standing position between COPD patients and normal subjects: Time-resolved quantitative evaluation using dynamic chest radiography with flat panel detector system (“dynamic X-ray phrenicography”)

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yoshitake, E-mail: yamada@rad.med.keio.ac.jp [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Ueyama, Masako, E-mail: ueyamam@fukujuji.org [Department of Health Care, Fukujuji Hospital, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose, Tokyo 204-8522 (Japan); Abe, Takehiko, E-mail: takehikoabe@hotmail.com [Department of Radiology, Fukujuji Hospital, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose, Tokyo 204-8522 (Japan); Araki, Tetsuro, E-mail: TARAKI@partners.org [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); Abe, Takayuki, E-mail: abe.t@keio.jp [Department of Preventive Medicine and Public Health, Biostatistics Unit at Clinical and Translational Research Center, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Nishino, Mizuki, E-mail: Mizuki_Nishino11@dfci.harvard.edu [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); Jinzaki, Masahiro, E-mail: jinzaki@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Hatabu, Hiroto, E-mail: hhatabu@partners.org [Department of Radiology, Center for Pulmonary Functional Imaging, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02215 (United States); and others

    2017-02-15

    Highlights: • Dynamic X-ray phrenicography is a useful method for the evaluation of the diaphragms. • Its radiation dose is comparable to conventional two projection chest radiography. • Diaphragm motion during tidal breathing is larger in COPD than in normal subjects. • Higher BMI is also associated with increased excursions of the bilateral diaphragm. - Abstract: Objectives: To quantitatively compare diaphragmatic motion during tidal breathing in a standing position between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography. Materials and methods: Thirty-nine COPD patients (35 males; age, 71.3 ± 8.4 years) and 47 normal subjects (non-smoker healthy volunteers) (20 males; age, 54.8 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions and peak motion speeds of the diaphragms. The results were analyzed using an unpaired t-test and a multiple linear regression model. Results: The excursions of the diaphragms in COPD patients were significantly larger than those in normal subjects (right, 14.7 ± 5.5 mm vs. 10.2 ± 3.7 mm, respectively, P < 0.001; left, 17.2 ± 4.9 mm vs. 14.9 ± 4.2 mm, respectively, P = 0.022). Peak motion speeds in inspiratory phase were significantly faster in COPD patients compared to normal subjects (right, 16.3 ± 5.0 mm/s vs. 11.8 ± 4.2 mm/s, respectively, P < 0.001; left, 18.9 ± 4.9 mm/s vs. 16.7 ± 4.0 mm/s, respectively, P = 0.022). The multivariate analysis demonstrated that having COPD and higher body mass index were independently associated with increased excursions of the bilateral diaphragm (all P < 0.05), after adjusting for other clinical variables. Conclusions: Time-resolved quantitative evaluation of the diaphragm using dynamic chest radiography demonstrated that the diaphragmatic motion during tidal breathing in a standing position is larger and

  10. Digital chest radiography system with amorphous selenium flat-panel detectors: qualitative and dosimetric comparison with a dedicated film-screen system

    International Nuclear Information System (INIS)

    Prato, Antonio; Fava Cesare; Ropolo, Roberto

    2005-01-01

    Purpose. To compare the quality and radiation dose of a conventional film-screen system and a digital system with amorphous selenium detectors in the study of the chest, by verifying overall performance and exposure levels for the main chest structures in patients of different sizes. Materials and methods. An analogic system (Chest Changer, Dupont, Day-light model 1000) and a digital system (Directray Rad 1000C, Hologic) were tested on a total of 1000 patients randomly assigned to one of two groups of 500 subjects.The patients were further subdivided according to BMI (Body Mass Index). Image quality was determined by two chest radiologists who evaluated eight anatomical structures. The entrance surface dose (skin-dose), calculated based on the exposure parameters, was taken as the patient dose. Results. Mean dose delivered was very similar for both techniques in the PA view (0.28 mGy), but it was greater in the LL projections obtained with the digital system (1.20 rnGy versus 0.83 mGy). The highest overall scores were assigned to 43% and 23.2% analogic radiograms and 64% and 70.2% digital radiograms, for the PA and LL projections respectively. The scores assigned to the various anatomical structures confirmed the better performance of the digital system in almost all of the regions considered. Conclusions. The mean quality of radiograms is definitely higher with the digital system, in particular in the LL projections, where the higher patient doses are counterbalanced by fewer repeated scans. The greater level of exposure in the digital system appears nonetheless tolerable on account of the greater informativeness and therefore diagnostic gain and also considering the possibilities for improving the system [it

  11. Time-Resolved Quantitative Analysis of the Diaphragms During Tidal Breathing in a Standing Position Using Dynamic Chest Radiography with a Flat Panel Detector System ("Dynamic X-Ray Phrenicography"): Initial Experience in 172 Volunteers.

    Science.gov (United States)

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto; Kudoh, Shoji

    2017-04-01

    Diaphragmatic motion in a standing position during tidal breathing remains unclear. The purpose of this observational study was to evaluate diaphragmatic motion during tidal breathing in a standing position in a health screening center cohort using dynamic chest radiography in association with participants' demographic characteristics. One hundred seventy-two subjects (103 men; aged 56.3 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions of and peak motion speeds of the diaphragms. Associations between the excursions and participants' demographics (gender, height, weight, body mass index [BMI], smoking history, tidal volume, vital capacity, and forced expiratory volume) were investigated. The average excursion of the left diaphragm (14.9 ± 4.6 mm, 95% CI 14.2-15.5 mm) was significantly larger than that of the right (11.0 ± 4.0 mm, 95% CI 10.4-11.6 mm) (P <0.001). The peak motion speed of the left diaphragm (inspiratory, 16.6 ± 4.2 mm/s; expiratory, 13.7 ± 4.2 mm/s) was significantly faster than that of the right (inspiratory, 12.4 ± 4.4 mm/s; expiratory, 9.4 ± 3.8 mm/s) (both P <0.001). Both simple and multiple regression models demonstrated that higher BMI and higher tidal volume were associated with increased excursions of the bilateral diaphragm (all P <0.05). The average excursions of the diaphragms are 11.0 mm (right) and 14.9 mm (left) during tidal breathing in a standing position. The diaphragmatic motion of the left is significantly larger and faster than that of the right. Higher BMI and tidal volume are associated with increased excursions of the bilateral diaphragm. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  12. 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.

    Science.gov (United States)

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto; Kudoh, Shoji

    2017-07-01

    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. 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, 54.8±9.8 years) underwent sequential chest radiographs during tidal breathing in a standing position using dynamic chest radiography with a flat panel detector system. We evaluated the craniocaudal gradient of MPCR. The results were analyzed using an unpaired t-test and the Tukey-Kramer method. The craniocaudal gradients of MPCR in COPD patients were significantly lower than those in normal subjects (right inspiratory phase, 75.5±48.1 vs. 108.9±42.0s -1 cm -1 , P<0.001; right expiratory phase, 66.4±40.6 vs. 89.8±31.6s -1 cm -1 , P=0.003; left inspiratory phase, 75.5±48.2 vs. 108.2±47.2s -1 cm -1 , P=0.002; left expiratory phase, 60.9±38.2 vs. 84.3±29.5s -1 cm -1 , P=0.002). No significant differences in height, weight, or BMI were observed between COPD and normal groups. In the sub-analysis, the gradients in severe COPD patients (global initiative for chronic obstructive lung disease [GOLD] 3 or 4, n=26) were significantly lower than those in mild COPD patients (GOLD 1 or 2, n=17) for both right and left inspiratory/expiratory phases (all P≤0.005). A decrease of the craniocaudal gradient of MPCR was observed in COPD patients. The craniocaudal gradient was lower in severe COPD patients than in mild COPD patients. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  13. Scan equalization digital radiography (SEDR) implemented with an amorphous selenium flat-panel detector: initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xinming; Lai Chaojen; Chen Lingyun; Han Tao; Zhong Yuncheng; Shen Youtao; Wang Tianpeng; Shaw, Chris C [Department of Imaging Physics, Digital Imaging Research Laboratory, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4009 (United States)], E-mail: xliu@di.mdacc.tmc.edu

    2009-11-21

    It is well recognized in projection radiography that low-contrast detectability suffers in heavily attenuating regions due to excessively low x-ray fluence to the image receptor and higher noise levels. Exposure equalization can improve image quality by increasing the x-ray exposure to heavily attenuating regions, resulting in a more uniform distribution of exposure to the detector. Image quality is also expected to be improved by using the slot-scan geometry to reject scattered radiation effectively without degrading primary x-rays. This paper describes the design of a prototype scan equalization digital radiography (SEDR) system implemented with an amorphous silicon (a-Si) thin-film transistor (TFT) array-based flat-panel detector. With this system, slot-scan geometry with alternate line erasure and readout (ALER) technique was used to achieve scatter rejection. A seven-segment beam height modulator assembly was mounted onto the fore collimator to regulate exposure regionally for chest radiography. The beam modulator assembly, consisting of micro linear motors, lead screw cartridge with lead (Pb) beam blockers attached, position feedback sensors and motor driver circuitry, has been tested and found to have an acceptable response for exposure equalization in chest radiography. An anthropomorphic chest phantom was imaged in the posterior-anterior (PA) view under clinical conditions. Scatter component, primary x-rays, scatter-to-primary ratios (SPRs) and primary signal-to-noise ratios (PSNRs) were measured in the SEDR images to evaluate the rejection and redistribution of scattered radiation, and compared with those for conventional full-field imaging with and without anti-scatter grid methods. SPR reduction ratios (SPRRRs, defined as the differences between the non-grid full-field SPRs and the reduced SPRs divided by the former) yielded approximately 59% for the full-field imaging with grid and 82% for the SEDR technique in the lungs, and 77% for the full

  14. Performance Characteristic of a CsI(Tl) Flat Panel Detector Radiography System

    International Nuclear Information System (INIS)

    Jeong, Hoi Woun; Min, Jung Hwan; Kim, Jung Min; Park, Min Seok; Lee, Gaung Young

    2012-01-01

    The purpose of this work was to evaluate an amorphous silicon cesium iodide based indirect flat-panel detector (FPD) in terms of their modulation transfer function (MTF), Wiener spectrum (WS, or noise power spectrum, NPS), and detective quantum efficiency (DQE). Measurements were made on flat-panel detector using the International Electrotechnical Commission (IEC) defined RQA3, RQA5, RQA7, and RQA9 radiographic technique. The MTFs of the systems were measured using an edge method. The WS(NPS) of the systems were determined for a range of exposure levels by two-dimensional (2D). Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, WS(NPS), exposure, and estimated ideal signal-to-noise ratios. Characteristic curve in the RQA3 showed difference in the characteristic curve from RQA5, RQA7, RQA9. MTFs were not differences according to x-ray beam quality. WS(NPS) was reduced with increasing dose, and RQA 3, RQA5, RQA7, RQA9 as the order is reduced. DQE represented the best in the 1mR, RQA 3, RQA5, RQA7, RQA9 decrease in the order. The physical imaging characteristics of FPD may also differ from input beam quality. This study gives an initial motivation that the physical imaging characteristics of FPD is an important issue for the right use of digital radiography system.

  15. Performance Characteristic of a CsI(Tl) Flat Panel Detector Radiography System

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hoi Woun [Dept. of Radiological Science, Baekseok Culture University, Seoul (Korea, Republic of); Min, Jung Hwan [Dept. of Radiological Technology, Shingu University, Seongnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Science, Korea University, Health Science College, Seoul (Korea, Republic of); Park, Min Seok [Korea Institue of Radiological and Medical Sicences, Research Institute of Radiologycal and Medical Sciences, Seoul (Korea, Republic of); Lee, Gaung Young [National Institute of Food and Drug Safety Evaluation, Seoul (Korea, Republic of)

    2012-06-15

    The purpose of this work was to evaluate an amorphous silicon cesium iodide based indirect flat-panel detector (FPD) in terms of their modulation transfer function (MTF), Wiener spectrum (WS, or noise power spectrum, NPS), and detective quantum efficiency (DQE). Measurements were made on flat-panel detector using the International Electrotechnical Commission (IEC) defined RQA3, RQA5, RQA7, and RQA9 radiographic technique. The MTFs of the systems were measured using an edge method. The WS(NPS) of the systems were determined for a range of exposure levels by two-dimensional (2D). Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, WS(NPS), exposure, and estimated ideal signal-to-noise ratios. Characteristic curve in the RQA3 showed difference in the characteristic curve from RQA5, RQA7, RQA9. MTFs were not differences according to x-ray beam quality. WS(NPS) was reduced with increasing dose, and RQA 3, RQA5, RQA7, RQA9 as the order is reduced. DQE represented the best in the 1mR, RQA 3, RQA5, RQA7, RQA9 decrease in the order. The physical imaging characteristics of FPD may also differ from input beam quality. This study gives an initial motivation that the physical imaging characteristics of FPD is an important issue for the right use of digital radiography system.

  16. Initial experiences in clinical application of the THORAX-FD: flat-panel detector radiography in thoracic diagnosis

    International Nuclear Information System (INIS)

    Herrmann, K.A.; Staebler, A.; Bonel, H.; Kulinna, C.; Holzknecht, N.; Reiser, M.F.; Geiger, B.; Boehm, S.; Maschke, M.

    2000-01-01

    The flat-panel detector closes the gap between radiography and the digital diagnostics equipment currently in use. In addition to the dose reduction that can be expected, the availability of diagnostic information in digital form enables the user to optimize the clinical workflow and to network radiography directly with a digital archiving and communication system. (orig.)

  17. Portable low-cost flat panel detectors for real-time digital radiography

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    Iovea, Mihai; Neagu, Marian; Stefanescu, Bogdan; Mateiasi, Gabriela; Porosnicu, Ioana; Angheluta, Elena [Accent Pro 2000 S.R.L., Bucharest (Romania)

    2015-07-01

    The X-ray inspection is one of the most common used non-destructive testing methods in industry applications, but for the portable X-ray digital solution are not so many accessible, low-cost and versatile detection devices. The efficiency of a non-destructive X-ray portable device is represented by the quality of digital images, by its low acquisition time combined with a high resolution, in condition of low noise and at an affordable cost. The paper presents two X-ray portable imaging systems developed by us, suitable also for aerospace NDT applications, which are also very versatile for being easily adapted for other fields that requires mobile solutions. The first device described in the paper represent a portable large-size (210 mm X 550 mm) and high-resolution (27/54 microns) flat panel detector based on linear translation of a X-Ray TDI detector, destined for various components/parts real-time transmission measurements. The second system it is also a flat panel detectors, with a size of 510 mm X 610 mm, with the detector size from 0.2 mm until 1.5 mm, which can operate by applying the dual-energy method, very useful for discriminating materials by evaluating their Atomic effective number. The high resolution and low-cost of this flat-panels widens their applicability by covering large requirements, from identifying unwanted materials within a structure until detection of very thin cracks in complex components.

  18. Portable low-cost flat panel detectors for real-time digital radiography

    International Nuclear Information System (INIS)

    Iovea, Mihai; Neagu, Marian; Stefanescu, Bogdan; Mateiasi, Gabriela; Porosnicu, Ioana; Angheluta, Elena

    2015-01-01

    The X-ray inspection is one of the most common used non-destructive testing methods in industry applications, but for the portable X-ray digital solution are not so many accessible, low-cost and versatile detection devices. The efficiency of a non-destructive X-ray portable device is represented by the quality of digital images, by its low acquisition time combined with a high resolution, in condition of low noise and at an affordable cost. The paper presents two X-ray portable imaging systems developed by us, suitable also for aerospace NDT applications, which are also very versatile for being easily adapted for other fields that requires mobile solutions. The first device described in the paper represent a portable large-size (210 mm X 550 mm) and high-resolution (27/54 microns) flat panel detector based on linear translation of a X-Ray TDI detector, destined for various components/parts real-time transmission measurements. The second system it is also a flat panel detectors, with a size of 510 mm X 610 mm, with the detector size from 0.2 mm until 1.5 mm, which can operate by applying the dual-energy method, very useful for discriminating materials by evaluating their Atomic effective number. The high resolution and low-cost of this flat-panels widens their applicability by covering large requirements, from identifying unwanted materials within a structure until detection of very thin cracks in complex components.

  19. Contrast-detail analysis of three flat panel detectors for digital radiography

    International Nuclear Information System (INIS)

    Borasi, Giovanni; Samei, Ehsan; Bertolini, Marco; Nitrosi, Andrea; Tassoni, Davide

    2006-01-01

    In this paper we performed a contrast detail analysis of three commercially available flat panel detectors, two based on the indirect detection mechanism (GE Revolution XQ/i, system A, and Trixell/Philips Pixium 4600, system B) and one based on the direct detection mechanism (Hologic DirectRay DR 1000, system C). The experiment was conducted using standard x-ray radiation quality and a widely used contrast-detail phantom. Images were evaluated using a four alternative forced choice paradigm on a diagnostic-quality softcopy monitor. At the low and intermediate exposures, systems A and B gave equivalent performances. At the high dose levels, system A performed better than system B in the entire range of target sizes, even though the pixel size of system A was about 40% larger than that of system B. At all the dose levels, the performances of the system C (direct system) were lower than those of system A and B (indirect systems). Theoretical analyses based on the Perception Statistical Model gave similar predicted SNR T values corresponding to an observer efficiency of about 0.08 for systems A and B and 0.05 for system C

  20. Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

    International Nuclear Information System (INIS)

    Ravindran, V. R.; Sreelakshmi, C.; Vibin

    2008-01-01

    The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

  1. The effect of dose reduction on image quality in digital radiography using a flat-panel detector: experimental study in rabbits

    International Nuclear Information System (INIS)

    Jung, Sung Il; Goo, Jin Mo; Lee, Hyun Ju; Moon, Woo Kyung; Lim, Kun Young; Cho, Gyung Goo; Kim, Ji Hoon; Im, Jung Gi; Choi, Jang Yong; Nam, Sang Hee

    2005-01-01

    To evaluate the effect of dose reduction on image quality in digital radiography using a flat-panel detector. Digital radiographs of 30 rabbits were obtained at two different dose levels (33.23 μGY for the standard dose group and 20.09 μGY for the reduced dose group). The amorphous selenium-based flat-panel detector system had a panel size of 7 x 8.5 inches, a matrix of 1280 x 1536 (pixels?), and a pixel pitch of 138 μm. Four observers evaluated the soft-copy images on a high-resolution video monitor (2560 x 2048 x 8 bits) in random order. The observers rated the visibility of 13 different anatomic structures on a 5-point scale, viz, the retrocardiac lung, subdiaphragmatic lung, heart border, diaphragmatic border, proximal airway, unobscured lung, liver border, kidney border, bowel gas, flank stripe, ribs, and vertebrae in the mediastinal and abdominal regions. Statistical significance was determined using Wilcoxon's signed rank test. There was no statistically significant difference in the visibility of the anatomic structures on digital radiography between the standard and reduced dose groups. Digital radiography using an amorphous selenium-based flat-panel detector can preserve the image quality, though the dose is reduced to 40% of the standard level

  2. The effect of dose reduction on image quality in digital radiography using a flat-panel detector: experimental study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung Il; Goo, Jin Mo; Lee, Hyun Ju; Moon, Woo Kyung; Lim, Kun Young; Cho, Gyung Goo; Kim, Ji Hoon; Im, Jung Gi [Seoul National College of Medicine, Seoul (Korea, Republic of); Choi, Jang Yong; Nam, Sang Hee [Inje University, Seoul (Korea, Republic of)

    2005-07-15

    To evaluate the effect of dose reduction on image quality in digital radiography using a flat-panel detector. Digital radiographs of 30 rabbits were obtained at two different dose levels (33.23 {mu}GY for the standard dose group and 20.09 {mu}GY for the reduced dose group). The amorphous selenium-based flat-panel detector system had a panel size of 7 x 8.5 inches, a matrix of 1280 x 1536 (pixels?), and a pixel pitch of 138 {mu}m. Four observers evaluated the soft-copy images on a high-resolution video monitor (2560 x 2048 x 8 bits) in random order. The observers rated the visibility of 13 different anatomic structures on a 5-point scale, viz, the retrocardiac lung, subdiaphragmatic lung, heart border, diaphragmatic border, proximal airway, unobscured lung, liver border, kidney border, bowel gas, flank stripe, ribs, and vertebrae in the mediastinal and abdominal regions. Statistical significance was determined using Wilcoxon's signed rank test. There was no statistically significant difference in the visibility of the anatomic structures on digital radiography between the standard and reduced dose groups. Digital radiography using an amorphous selenium-based flat-panel detector can preserve the image quality, though the dose is reduced to 40% of the standard level.

  3. On site evaluation of three flat panel detectors for digital radiography

    International Nuclear Information System (INIS)

    Borasi, Giovanni; Nitrosi, Andrea; Ferrari, Paolo; Tassoni, Davide

    2003-01-01

    During a tender we evaluated the image performance of three commercially available active matrix flat panel imagers (AMFPI) for general radiography, one based on direct detection method (Se photoconductor) the other two on indirect detection method (CsI phosphor). Basic image quality parameters (MTF, NNPS, DQE) were evaluated with particular attention to dose and energy dependence. As it is known, presampling modulation transfer function (MTF) of selenium based detector is very high (at 70 kV, 2 cycles/mm, 2.5 μGy, about 0.80). Indirect detection panels exhibit a comparable (lower) resolution (at 70 kV, 2 cycles/mm, 2.5 μGy, MTF is about 0.34 for both the systems analyzed) and a more pronounced energy and dose dependence could also be noted in one of them. As a consequence of the very high resolution, the normalized noise power spectrum (NNPS) of the direct system is substantially flat, very similar to a white noise. Considering that the sensitive layer of all detectors is the same (0.5 mm), the relatively higher NNPS values are related to selenium absorption properties (lower Z respect to CsI:Tl) and detector inherent noise. NNPSs of the other systems, at low frequencies, are comparable but the frequency dependence is significantly different. At 70 kV, 2.5 μGy, 0.5 cycles/mm detective quantum efficiency (DQE) is about 0.35 for the direct detection system, and about the same (0.6) for the indirect ones. The combined effect of additive and multiplicative noise components makes DQE dependence on dose not monotonic. DQE present a maximum for an intermediate exposure. This complex behavior may be useful to characterize the systems in terms of the monodimensional integral over the frequency of DQE (IDQE). Both visual contrast-detail experiment and the direct evaluation of the signal-to-noise ratio confirmed, at least in a qualitative way, the system performances predicted by IDQE

  4. Present and future of flat panel detectors in the world

    International Nuclear Information System (INIS)

    Inamura, Kiyonari

    2002-01-01

    Present status of development of flat panel detectors and their clinical application in the world have been surveyed, and future trends are also explored especially in the field of material researches and methods of manufacturing. Also the importance of role of medical physicists on user side is described because characteristic physics measurement of a detector assembly is unavoidable and essential in quality assurance in clinical routine and acceptance test in hospitals. Even though physics measurements and clinical evaluations on flat panel detectors have shown remarkable progress and advances in these several years, future problems of cost down in manufacturing and quality assurance to prevent individual differences between detector assemblies must be resolved. Results of evaluation in mammography, chest radiography, fluoroscopy for cardiovascular examination, bone tumor examination and radiotherapy application indicate that flat panel detectors are future promising materials. Their systematic operation is contributing to heighten accuracy of image examinations and preciseness of radiation therapy. Encouragement to medical physicists relevant to flat panel detectors is also raised in this paper. (author)

  5. Flat-panel detectors in x-ray diagnosis

    International Nuclear Information System (INIS)

    Spahn, M.; Heer, V.; Freytag, R.

    2003-01-01

    For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography, mammography and cardiologic angiography flat-panel detectors are already well established while they are made ready for market introduction in general angiography and fluoroscopy. Two flat-panel detector technologies are available. One technology is based on an indirect conversion process of X-rays while the other one uses a direct conversion method.For radiography and dynamic applications the indirect method provides substantial advantages, while the direct method has some benefits for mammography. In radiography and mammography flat-panel detectors lead to clear improvements with respect to workflow, image quality and dose reduction potentials. These improvements are fostered by the immediate availability of the image, the large dynamic range and the high sensitivity to X-rays. New applications and the use of complex image processing algorithms have the potential to enlarge the present diagnostic range of applications.Up to now, image intensifiers are still the well-established technology for angiography and fluoroscopy. Nevertheless flat-panel detectors begin to enter this field, especially in cardiologic angiography.Characteristics of flat-panel detectors such as the availability of distortion-free images, the excellent contrast resolution, the large dynamic range, the high sensitivity to X-rays and the usability in magnetic fields provide the basis for improved and new diagnostic and interventional methods. (orig.) [de

  6. Digital radiography with a large-scale electronic flat-panel detector vs screen-film radiography: observer preference in clinical skeletal diagnostics

    International Nuclear Information System (INIS)

    Hamers, S.; Freyschmidt, J.; Neitzel, U.

    2001-01-01

    The imaging performance of a recently developed digital flat-panel detector system was compared with conventional screen-film imaging in an observer preference study. In total, 34 image pairs of various regions of the skeleton were obtained in 24 patients; 30 image pairs were included in the study. The conventional images were acquired with 250- and 400-speed screen-film combinations, using the standard technique of our department. Within hours, the digital images were obtained using identical exposure parameters. The digital system employed a large-area (43 x 43 cm) flat-panel detector based on amorphous silicon (Trixell Pixium 4600), integrated in a Bucky table. Six radiologists independently evaluated the image pairs with respect to image latitude, soft tissue rendition, rendition of the periosteal and enosteal border of cortical bone, rendition of cancellous bone and the visibility of potentially present pathological changes, using a subjective five-point scale. The digital images were rated significantly (p=0.001) better than the screen-film images with respect to soft tissue rendition and image latitude. Also the rendition of the cancellous bone and the periosteal and enosteal border of the cortical bone was rated significantly (p=0.05) better for the flat-panel detector. The visibility of pathological lesions was equivalent; only large-area sclerotic lesions (n=2) were seen superiorly on screen-film images. The new digital flat-panel detector based on amorphous silicon appears to be at least equivalent to conventional screen-film combinations for skeletal examinations, and in most respects even superior. (orig.)

  7. Clinical evaluation of digital radiography based on a large-area cesium iodide-amorphous silicon flat-panel detector compared with screen-film radiography for skeletal system and abdomen

    International Nuclear Information System (INIS)

    Okamura, Terue; Tanaka, Saori; Koyama, Koichi; Norihumi, Nishida; Daikokuya, Hideo; Matsuoka, Toshiyuki; Yamada, Ryusaku; Kishimoto, Kenji; Hatagawa, Masakatsu; Kudoh, Hiroaki

    2002-01-01

    The aim of this clinical study was to compare the image quality of digital radiography using the new digital Bucky system based on a flat-panel detector with that of a conventional screen-film system for the skeletal structure and the abdomen. Fifty patients were examined using digital radiography with a flat-panel detector and screen-film systems, 25 for the skeletal structures and 25 for the abdomen. Six radiologists judged each paired image acquired under the same exposure parameters concerning three observation items for the bone and six items for the abdomen. Digital radiographic images for the bone were evaluated to be similar to screen-film images at the mean of 42.2%, to be superior at 50.2%, and to be inferior at 7.6%. Digital radiographic images for the abdomen were judged to be similar to screen-film images at the mean of 43.4%, superior at 52.4%, and inferior at 4.2%; thus, digital radiographic images were estimated to be either similar as or superior to screen-film images at over 92% for the bone and abdomen. On the statistical analysis, digital radiographic images were also judged to be preferred significantly in the most items for the bone and abdomen. In conclusion, the image quality of digital radiography with a flat-panel detector was superior to that of a screen-film system under the same exposure parameters, suggesting that dose reduction is possible with digital radiography. (orig.)

  8. Digital radiography of the chest in pediatric patients

    International Nuclear Information System (INIS)

    Puig, S.

    2003-01-01

    The hopes placed in digital radiography have been fulfilled only partly in pediatric radiology. Specifically, the option of gaining reduced radiation exposure in combination with a similar or even improved image quality was hard to realize. The only portable digital system available for a long time were storage phosphors which were disadvantaged by an extremely limited dose-quantum-efficiency (DQE) in comparison to digital flat panel detectors. New developments and the introduction of the dual-reading system led to image qualities comparable to film-screen-systems with high resolution and achievable without dose increase, sometimes even with dose reduction. A study using an animal model suggests that these systems can even be used in preterm infants with very low birth weights. A new portable flat panel detector by Canon may improve digital chest radiography in pediatric patients. (orig.) [de

  9. Evaluation of a flat-panel detector system

    International Nuclear Information System (INIS)

    Sato, Masami; Eguchi, Yoichi; Yamada, Kinichi; Kaga, Yuji; Endo, Yutaka; Yamazaki, Tatsuya

    2001-01-01

    We evaluated the imaging performance of a flat-panel detector digital radiography system (CXDI-11 X-ray Digital Camera, Canon Inc.) and a computed radiography system (FCR9000C-HQ, Fuji Film). The characteristics of the two detectors and of the overall systems were compared. This included evaluation and comparison of the fundamental physical characteristics, including x-ray response curve, modulation transfer function (MTF), Wiener spectra, noise-equivalent quanta, and x-ray tube voltage-dependent detector response. Overall system performance was evaluated using receiver operating characteristic (ROC) analysis. The results of the study showed that the dynamic range of the CXDI-11 measured relative to the input x-ray flux was 10 3 , similar to that of the FCR9000C-HQ. Both systems showed similar final MTFs, although the pre-sampling MTF of the CXDI-11 was better than that of the FCR9000C-HQ. Noise analysis, based on noise-equivalent quanta and Wiener spectra, showed that for normal exposure conditions the CXDI-11 had superior performance. With both systems, x-ray response (system output/incident x-ray exposure) increased with increasing x-ray tube voltage. ROC analysis indicated that the CXDI-11 was superior in overall performance. (author)

  10. Resolution requirements for monitor viewing of digital flat-panel detector radiographs: a contrast detail analysis

    International Nuclear Information System (INIS)

    Peer, Siegfried; Giacomuzzi, Salvatore M.; Peer, Regina; Gassner, Eva; Steingruber, Iris; Jaschke, Werner

    2003-01-01

    With the introduction of digital flat-panel detector systems into clinical practice, the still unresolved question of resolution requirements for picture archiving communication system (PACS) workstation monitors has gained new momentum. This contrast detail analysis was thus performed to define the differences in observer performance in the detection of small low-contrast objects on clinical 1K and 2K monitor workstations. Images of the CDRAD 2.0 phantom were acquired at varying exposures on an indirect-type digital flat-panel detector. Three observers evaluated a total of 15 images each with respect to the threshold contrast for each detail size. The numbers of correctly identified objects were determined for all image subsets. No significant difference in the correct detection ratio was detected among the observers; however, the difference between the two types of workstations (1K vs 2K monitors) despite less than 3% was significant at a 95% confidence level. Slight but statistically significant differences exist in the detection of low-contrast nodular details visualized on 1K- and 2K-monitor workstations. Further work is needed to see if this result holds true also for comparison of clinical flat-panel detector images and may, for example, exert an influence on the diagnostic accuracy of chest X-ray readings. (orig.)

  11. Synchrotron applications of an amorphous silicon flat-panel detector

    International Nuclear Information System (INIS)

    Lee, J. H.; Can Aydiner, C.; Almer, J.; Bernier, J.; Chapman, K. W.; Chupas, P. J.; Haeffner, D.; Kump, K.; Lee, P. L.; Lienert, U.; Miceli, A.; Vera, G.; LANL; GE Healthcare

    2008-01-01

    A GE Revolution 41RT flat-panel detector (GE 41RT) from GE Healthcare (GE) has been in operation at the Advanced Photon Source for over two years. The detector has an active area of 41 cm x 41 cm with 200 (micro)m x 200 (micro)m pixel size. The nominal working photon energy is around 80 keV. The physical set-up and utility software of the detector system are discussed in this article. The linearity of the detector response was measured at 80.7 keV. The memory effect of the detector element, called lag, was also measured at different exposure times and gain settings. The modulation transfer function was measured in terms of the line-spread function using a 25 (micro)m x 1 cm tungsten slit. The background (dark) signal, the signal that the detector will carry without exposure to X-rays, was measured at three different gain settings and with exposure times of 1 ms to 15 s. The radial geometric flatness of the sensor panel was measured using the diffraction pattern from a CeO 2 powder standard. The large active area and fast data-capturing rate, i.e. 8 frames s -1 in radiography mode, 30 frames s -1 in fluoroscopy mode, make the GE 41RT one of a kind and very versatile in synchrotron diffraction. The loading behavior of a Cu/Nb multilayer material is used to demonstrate the use of the detector in a strain-stress experiment. Data from the measurement of various samples, amorphous SiO 2 in particular, are presented to show the detector effectiveness in pair distribution function measurements

  12. Digital chest radiography

    DEFF Research Database (Denmark)

    Debess, Jeanne Elisabeth; Johnsen, Karen Kirstine; Thomsen, Henrik

    on collimation and dose reduction in digital chest radiography Methods and Materials A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from one hundred fifty self-reliant female patients between 15 and 55 years...

  13. Chest X-Ray (Chest Radiography)

    Science.gov (United States)

    ... Resources Professions Site Index A-Z X-ray (Radiography) - Chest Chest x-ray uses a very small dose ... Radiography? What is a Chest X-ray (Chest Radiography)? The chest x-ray is the most commonly performed diagnostic ...

  14. Chest radiography after minor chest trauma

    Energy Technology Data Exchange (ETDEWEB)

    Rossen, B.; Laursen, N.O.; Just, S.

    The results of chest radiography in 581 patients with blunt minor thoracic trauma were reviewed. Frontal and lateral views of the chest indicated pathology in 72 patients (12.4%). Pneumothorax was present in 16 patients; 4 had hemothorax. The physical examination and the results of chest radiography were not in accordance because in 6(30%) of the 20 patients with hemo/-pneumothorax the physical examination was normal. Consequently there is wide indication for chest radiography after minor blunt chest trauma.

  15. Digital chest radiography

    DEFF Research Database (Denmark)

    Debess, Jeanne Elisabeth; Vejle-Sørensen, Jens Kristian; Thomsen, Henrik

    ,3 mAs and SID SID of 180 centimetres using a phantom and lithium fluoride thermo luminescence dosimeter (TLD). Dose to risk organs mamma, thyroid and colon are measured at different collimations with one-centimetre steps. TLD results are used to estimate dose reduction for different collimations...... at the conference. Conclusion: Collimation improvement in basic chest radiography can reduce the radiation to female patients at chest x-ray examinations....

  16. Chest radiography after minor chest trauma

    International Nuclear Information System (INIS)

    Rossen, B.; Laursen, N.O.; Just, S.

    1987-01-01

    The results of chest radiography in 581 patients with blunt minor thoracic trauma were reviewed. Frontal and lateral views of the chest indicated pathology in 72 patients (12.4%). Pneumothorax was present in 16 patients; 4 had hemothorax. The physical examination and the results of chest radiography were not in accordance because in 6(30%) of the 20 patients with hemo/-pneumothorax the physical examination was normal. Consequently there is wide indication for chest radiography after minor blunt chest trauma. (orig.)

  17. Imaging responses of on-site CsI and Gd2O2S flat-panel detectors: Dependence on the tube voltage

    Science.gov (United States)

    Jeon, Hosang; Chung, Myung Jin; Youn, Seungman; Nam, Jiho; Lee, Jayoung; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Ho Kyung

    2015-07-01

    One of the emerging issues in radiography is low-dose imaging to minimize patient's exposure. The scintillating materials employed in most indirect flat-panel detectors show a drastic change of X-ray photon absorption efficiency around their K-edge energies that consequently affects image quality. Using various tube voltages, we investigated the imaging performance of most popular scintillators: cesium iodide (CsI) and gadolinium oxysulfide (Gd2O2S). The integrated detective quantum efficiencies (iDQE) of four detectors installed in the same hospital were evaluated according to the standardized procedure IEC 62220-1 at tube voltages of 40 - 120 kVp. The iDQE values of the Gd2O2S detectors were normalized by those of CsI detectors to exclude the effects of image postprocessing. The contrast-to-noise ratios (CNR) were also evaluated by using an anthropomorphic chest phantom. The iDQE of the CsI detector outperformed that of the Gd2O2S detector over all tube voltages. Moreover, we noted that the iDQE of the Gd2O2S detectors quickly rolled off with decreasing tube voltage under 70 kVp. The CNRs of the two scintillators were similar at 120 kVp. At 60 kVp, however, the CNR of Gd2O2S was about half that of CsI. Compared to the Gd2O2S detectors, variations in the DQE performance of the CsI detectors were relatively immune to variations in the applied tube voltages. Therefore, we claim that Gd2O2S detectors are inappropriate for use in low-tube-voltage imaging (e.g., extremities and pediatrics) with low patient exposure.

  18. Mass chest radiography in Greece

    International Nuclear Information System (INIS)

    Papavasiliou, C.

    1987-01-01

    In Greece mass chest radiography has been performed regularly on various population groups as a measure to control tuberculosis. Routine chest radiography is performed in most Greek hospitals on admission. In this report available data-admittedly inadequate-directly or indirectly addressing the problem of benefit versus the risk or cost associated with this examination is presented

  19. Comparison of imaging properties of direct-type and indirect-type of flat-panel detector

    International Nuclear Information System (INIS)

    Matsumoto, Masao; Suekane, Koji; Ichimaru, Yasunobu; Ogata, Yuji; Inamura, Kiyonari; Kanai, Kouzou; Kanamori, Hitoshi

    2002-01-01

    A Flat-Panel Detector (FPD) has many advantages such as eliminating cassette handling and being able to display a preview image immediately in addition to the digital image processing and the networking. Thus, the FPD has ability to innovate the radiology department. We measured and evaluated the digital and over-all imaging properties (characteristic curves, modulation Transfer Functions, Wiener spectra and Noise Equivalent Quanta (NEQ) for the direct-type and indirect-type of FPD. The pre-sampling and overall NEQ of the indirect-type of FPD were better than the NEQ of the direct-type of FPD at lower spatial frequencies, but were worse at higher spatial frequencies. The FPD can take image data at real-time and be easy to digitalize. From these results, Screen/Film system and Computed Radiography system will be replaced by the FPD system, together with diffusion of CAD, cone beam Computed Tomography (CT) system and open-type Magnetic Resonance Imagining (MRI) system. (T. Tanaka)

  20. Tracking brachytherapy sources using emission imaging with one flat panel detector

    International Nuclear Information System (INIS)

    Song Haijun; Bowsher, James; Das, Shiva; Yin Fangfang

    2009-01-01

    This work proposes to use the radiation from brachytherapy sources to track their dwell positions in three-dimensional (3D) space. The prototype device uses a single flat panel detector and a BB tray. The BBs are arranged in a defined pattern. The shadow of the BBs on the flat panel is analyzed to derive the 3D coordinates of the illumination source, i.e., the dwell position of the brachytherapy source. A kilovoltage x-ray source located 3.3 m away was used to align the center BB with the center pixel on the flat panel detector. For a test plan of 11 dwell positions, with an Ir-192 high dose rate unit, one projection was taken for each dwell point, and locations of the BB shadows were manually identified on the projection images. The 3D coordinates for the 11 dwell positions were reconstructed based on two BBs. The distances between dwell points were compared with the expected values. The average difference was 0.07 cm with a standard deviation of 0.15 cm. With automated BB shadow recognition in the future, this technique possesses the potential of tracking the 3D trajectory and the dwell times of a brachytherapy source in real time, enabling real time source position verification.

  1. Digital radiography of the chest

    International Nuclear Information System (INIS)

    Sakurai, Kenji; Hachiya, Junichi; Korenaga, Tateo; Nitatori, Toshiaki; Miyasaka, Yasuo; Furuya, Yoshiro

    1984-01-01

    Initial clinical experience in digital chest radiography utilizing photostimulable phosphor and scanning laser stimulated luminescence was reported. Image quality of conventional film/screen radiography and digital radiography was compared in 30 normal cases. Reflecting wide dynamic range of the system, improved image quality was confirmed in all 30 cases, particularly in visibility of various mediastinal structures and pulmonary vessels. High sensor sensitivity of the system enabled digital radiography to reduce radiation dose requirement significantly. Diagnostically acceptable chest images were obtained with approximately 1/5 of routine dose for conventional radiography without significant image quality degradation. Some artifact created by digital processing were mostly overcome by a routine use of simultaneous display of two different types of image processing and therefore was not an actual drawback from diagnostic standpoint. Further technical advancement of the system to be seen for digital storage, retrieval and tranceference of images. (author)

  2. Endobronchial Tuberculosis and Chest Radiography

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Sasani

    2016-03-01

    Full Text Available Endobronchial tuberculosis and chest radiography I read, with interest, the article entitled “Clinical and Para-clinical Presentations of Endobronchial Tuberculosis” by Ahmadi Hoseini H. S. et al. (1 published in this journal. I would like to focus on some details about the chest X-ray of patients as elaborated by the authors in the results section. Accordingly, the findings of chest radiography in the available patients were as follows: pulmonary consolidation (75%, reduced pulmonary volume (20%, and hilar adenopathy (10%. This is an incomplete statement because the authors did not explain whether there was any normal chest radiography in the study population. In addition, it is not clear whether the X-ray examinations of the patients were normal, how many abnormal plain films yielded the presented data. On the other hand, the fact that the studied patients had no normal chest radiography is  controversial since in the literature, 10-20% of the patients with endobronchial tuberculosis are reported to have normal chest X-ray (2, 3. In fact, this is one of the problems in the diagnosis of the disease, as well as a potential cause of delayed diagnosis and treatment of the patients. Therefore, the absence of normal chest radiographs is in contrast to the available literature, and if not an error, it could be a subject of further investigation.

  3. Modelling of scintillator based flat-panel detectors with Monte-Carlo simulations

    International Nuclear Information System (INIS)

    Reims, N; Sukowski, F; Uhlmann, N

    2011-01-01

    Scintillator based flat panel detectors are state of the art in the field of industrial X-ray imaging applications. Choosing the proper system and setup parameters for the vast range of different applications can be a time consuming task, especially when developing new detector systems. Since the system behaviour cannot always be foreseen easily, Monte-Carlo (MC) simulations are keys to gain further knowledge of system components and their behaviour for different imaging conditions. In this work we used two Monte-Carlo based models to examine an indirect converting flat panel detector, specifically the Hamamatsu C9312SK. We focused on the signal generation in the scintillation layer and its influence on the spatial resolution of the whole system. The models differ significantly in their level of complexity. The first model gives a global description of the detector based on different parameters characterizing the spatial resolution. With relatively small effort a simulation model can be developed which equates the real detector regarding signal transfer. The second model allows a more detailed insight of the system. It is based on the well established cascade theory, i.e. describing the detector as a cascade of elemental gain and scattering stages, which represent the built in components and their signal transfer behaviour. In comparison to the first model the influence of single components especially the important light spread behaviour in the scintillator can be analysed in a more differentiated way. Although the implementation of the second model is more time consuming both models have in common that a relatively small amount of system manufacturer parameters are needed. The results of both models were in good agreement with the measured parameters of the real system.

  4. Evaluation of imaging quality for flat-panel detector based low dose C-arm CT system

    International Nuclear Information System (INIS)

    Seo, Chang-Woo; Cha, Bo Kyung; Jeon, Sungchae; Huh, Young

    2015-01-01

    The image quality associated with the extent of the angle of gantry rotation, the number of projection views, and the dose of X-ray radiation was investigated in flat-panel detector (FPD) based C-arm cone-beam computed tomography (CBCT) system for medical applications. A prototype CBCT system for the projection acquisition used the X-ray tube (A-132, Varian inc.) having rhenium-tungsten molybdenum target and flat panel a-Si X-ray detector (PaxScan 4030CB, Varian inc.) having a 397 x 298 mm active area with 388 μm pixel pitch and 1024 x 768 pixels in 2 by 2 binning mode. The performance comparison of X-ray imaging quality was carried out using the Feldkamp, Davis, and Kress (FDK) reconstruction algorithm between different conditions of projection acquisition. In this work, head-and-dental (75 kVp/20 mA) and chest (90 kVp/25 mA) phantoms were used to evaluate the image quality. The 361 (30 fps x 12 s) projection data during 360 deg. gantry rotation with 1 deg. interval for the 3D reconstruction were acquired. Parke weighting function were applied to handle redundant data and improve the reconstructed image quality in a mobile C-arm system with limited rotation angles. The reconstructed 3D images were investigated for comparison of qualitative image quality in terms of scan protocols (projection views, rotation angles and exposure dose). Furthermore, the performance evaluation in image quality will be investigated regarding X-ray dose and limited projection data for a FPD based mobile C-arm CBCT system. (authors)

  5. Should 3K zoom function be used for detection of pneumothorax in cesium iodide/amorphous silicon flat-panel detector radiographs presented on 1K-matrix soft copies?

    International Nuclear Information System (INIS)

    Herrmann, Karin A.; Zech, C.J.; Reiser, M.F.; Bonel, H.M.; Staebler, A.; Voelk, M.; Strotzer, M.

    2006-01-01

    The purpose of the study was to evaluate observer performance in the detection of pneumothorax with cesium iodide and amorphous silicon flat-panel detector radiography (CsI/a-Si FDR) presented as 1K and 3K soft-copy images. Forty patients with and 40 patients without pneumothorax diagnosed on previous and subsequent digital storage phosphor radiography (SPR, gold standard) had follow-up chest radiographs with CsI/a-Si FDR. Four observers confirmed or excluded the diagnosis of pneumothorax according to a five-point scale first on the 1K soft-copy image and then with help of 3K zoom function (1K monitor). Receiver operating characteristic (ROC) analysis was performed for each modality (1K and 3K). The area under the curve (AUC) values for each observer were 0.7815, 0.7779, 0.7946 and 0.7066 with 1K-matrix soft copies and 0.8123, 0.7997, 0.8078 and 0.7522 with 3K zoom. Overall detection of pneumothorax was better with 3K zoom. Differences between the two display methods were not statistically significant in 3 of 4 observers (p-values between 0.13 and 0.44; observer 4: p=0.02). The detection of pneumothorax with 3K zoom is better than with 1K soft copy but not at a statistically significant level. Differences between both display methods may be subtle. Still, our results indicate that 3K zoom should be employed in clinical practice. (orig.)

  6. Correlation of contrast-detail analysis and clinical image quality assessment in chest radiography with a human cadaver study.

    Science.gov (United States)

    De Crop, An; Bacher, Klaus; Van Hoof, Tom; Smeets, Peter V; Smet, Barbara S; Vergauwen, Merel; Kiendys, Urszula; Duyck, Philippe; Verstraete, Koenraad; D'Herde, Katharina; Thierens, Hubert

    2012-01-01

    To determine the correlation between the clinical and physical image quality of chest images by using cadavers embalmed with the Thiel technique and a contrast-detail phantom. The use of human cadavers fulfilled the requirements of the institutional ethics committee. Clinical image quality was assessed by using three human cadavers embalmed with the Thiel technique, which results in excellent preservation of the flexibility and plasticity of organs and tissues. As a result, lungs can be inflated during image acquisition to simulate the pulmonary anatomy seen on a chest radiograph. Both contrast-detail phantom images and chest images of the Thiel-embalmed bodies were acquired with an amorphous silicon flat-panel detector. Tube voltage (70, 81, 90, 100, 113, 125 kVp), copper filtration (0.1, 0.2, 0.3 mm Cu), and exposure settings (200, 280, 400, 560, 800 speed class) were altered to simulate different quality levels. Four experienced radiologists assessed the image quality by using a visual grading analysis (VGA) technique based on European Quality Criteria for Chest Radiology. The phantom images were scored manually and automatically with use of dedicated software, both resulting in an inverse image quality figure (IQF). Spearman rank correlations between inverse IQFs and VGA scores were calculated. A statistically significant correlation (r = 0.80, P chest radiography. © RSNA, 2011.

  7. Performance evaluation of flat panel detector in x-ray fluoroscopy

    International Nuclear Information System (INIS)

    Grewal, R.K.; Mclean, I.D.

    2004-01-01

    Full text: Flat panel detectors are currently replacing the conventional image intensifiers in R-F imaging. We evaluated the performance of a biplane cardiac imaging system (Siemens Axiom Artis dBC), the image acquisition was based on a 25 cm diagonal digital fiat panel detector. Performance characteristics included image quality, typical patient entrance dose and measurement of input to the surface of flat detector. The results were compared with conventional image intensifier systems (Siemens Hicor Unit and Toshiba DPF 2000 A Biplane Unit) used in cardiac imaging at Westmead. Image quality and dose measurements were performed following standard protocols using Westmead test object and 20 cm solid water as absorber in the beam. For measurement of input to the surface of flat detector, 2 mm copper was placed on the collimator. Radcal 3cc and 180 cc ion chambers were used for dose measurements. Image quality: Our measurements on flat panel system indicate that high contrast resolution and threshold contrast is not affected by changing field size. This is expected due to minimum loss of signal in the imaging chain of digital systems and the independence of detector pixel size with change in field of view. While low contrast resolution was found to be similar to conventional systems, high contrast resolution was significantly superior using flat detector system for large and intermediate field of view (25-28 1p/cm against 18-20). Typical patient dose as measured using flat detector system was similar to the conventional Toshiba pulsed fluoroscopy system( ∼ 3 - 8 mGy/min depending on the field size). This was 40-50 % lower than our old Siemens hicore unit. Input to the surface of flat detector was found to vary with field size as is the case with a conventional II system. As described elsewhere, although there is no necessity to increase exposure or video gain in a digital magnification, digital data interpolation process introduces noise. As a result system

  8. Practical expressions describing detective quantum efficiency in flat-panel detectors

    Science.gov (United States)

    Kim, H. K.

    2011-11-01

    In radiology, image quality excellence is a balance between system performance and patient dose, hence x-ray systems must be designed to ensure the maximum image quality is obtained for the lowest consistent dose. The concept of detective quantum efficiency (DQE) is widely used to quantify, understand, measure, and predict the performance of x-ray detectors and imaging systems. Cascaded linear-systems theory can be used to estimate DQE based on the system design parameters and this theoretical DQE can be utilized for determining the impact of various physical processes, such as secondary quantum sinks, noise aliasing, reabsorption noise, and others. However, the prediction of DQE usually requires tremendous efforts to determine each parameter consisting of the cascaded linear-systems model. In this paper, practical DQE formalisms assessing both the photoconductor- and scintillator-based flat-panel detectors under quantum-noise-limited operation are described. The developed formalisms are experimentally validated and discussed for their limits. The formalisms described in this paper would be helpful for the rapid prediction of the DQE performances of developing systems as well as the optimal design of systems.

  9. Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality

    Science.gov (United States)

    Vano, E.; Geiger, B.; Schreiner, A.; Back, C.; Beissel, J.

    2005-12-01

    The practical aspects of the dosimetric and imaging performance of a digital x-ray system for cardiology procedures were evaluated. The system was configured with an image intensifier (II) and later upgraded to a dynamic flat panel detector (FD). Entrance surface air kerma (ESAK) to phantoms of 16, 20, 24 and 28 cm of polymethyl methacrylate (PMMA) and the image quality of a test object were measured. Images were evaluated directly on the monitor and with numerical methods (noise and signal-to-noise ratio). Information contained in the DICOM header for dosimetry audit purposes was also tested. ESAK values per frame (or kerma rate) for the most commonly used cine and fluoroscopy modes for different PMMA thicknesses and for field sizes of 17 and 23 cm for II, and 20 and 25 cm for FD, produced similar results in the evaluated system with both technologies, ranging between 19 and 589 µGy/frame (cine) and 5 and 95 mGy min-1 (fluoroscopy). Image quality for these dose settings was better for the FD version. The 'study dosimetric report' is comprehensive, and its numerical content is sufficiently accurate. There is potential in the future to set those systems with dynamic FD to lower doses than are possible in the current II versions, especially for digital cine runs, or to benefit from improved image quality.

  10. Comparison of dose and image quality of a Flat-panel detector and an image intensifier

    International Nuclear Information System (INIS)

    Lazzaro, M.; Friedrich, B.Q.; Luz, R.M. da; Silva, A.M.M. da

    2016-01-01

    With the development of new technologies, have emerged new conversion methods of X-ray image, such as flat panel detectors. The aim of this work is the comparison of entrance surface air kerma (ESAK) and image quality between an image intensifier type of detector (A) and a flat panel (B). The ESAK was obtained by placing a ionization chamber under PMMA simulators of 10, 20 and 30 cm and the image quality was obtained by using the TOR "1"8FG simulator. The ESAK to the equipment A is higher when compared to the equipment B. The high contrast resolution is better for the equipment A for all thicknesses of simulators. The equipment A has low contrast resolution with a better viewing threshold for thicknesses of 10 and 20 cm, and a worse performance for 30 cm. It is concluded that the equipment B has ESAK smaller and despite having lower resolution, in almost all cases, have appropriate image quality for diagnosis. (author)

  11. Pediatric radiation dose management in digital radiography

    International Nuclear Information System (INIS)

    Neitzel, U.

    2004-01-01

    Direct digital radiography (DR) systems based on flat-panel detectors offer improved dose management in pediatric radiography. Integration of X-ray generation and detection in one computer-controlled system provides better control and monitoring

  12. Patient dosimetry during chest radiography

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, O.; Kosutic, D.; Markovic, S.

    2004-01-01

    Reasons for the variation in patient doses from chest radiography procedure were investigated by assessing entrance skin doses from kerma-area product measurements. Data were collected from seven x-ray tubes in five hospitals involving 259 adult patients. The third quartile value was 0.81 mGy compared to general reference level of 0.30 mGy. The applied tube potential was main contributor to patient dose variation. If department use at least 90 k Vp, the mean entrance surface dose would be reduced ut to factor six. Modification of departmental procedure is correct approach for dose reduction in diagnostic radiology. (author) [sr

  13. Evaluation of patient exposure with Flat Panel Detector (FPD) in X-ray TV system

    International Nuclear Information System (INIS)

    Yamada, M.; Komiya, N.; Kawaguchi, A.; Suzuki, M.; Suzuki, Shoichi; Asada, Yasuki

    2008-01-01

    The use of flat-panel detector (FPD) systems in TV equipment for gastrointestinal tract examination is increasing. The use of FPD systems is believed to reduce the exposure dose. When our institution changed its TV equipment from an image intensifier (GE; MS90Tj) system to an FPD (Shimadzu; SONIALVISION safire DAR-3500) system, we measured the doses produced and carried out a comparative examination of the extent to which exposure could be reduced. Two TV systems were used. We used an analyzer to measure output waveform, tube voltage, and half-value layer (HVL), and an ionization chamber dosimeter to carry out dose-in-air measurements. Body thickness, number of image acquisitions, and fluoroscopy time are required for the calculation of entrance skin dose (ESD). We therefore measured body thicknesses in 1000 upper gastrointestinal tract (UGI) and barium enemas and obtained average body thicknesses for males and females by age group. Values used for number of image acquisitions and fluoroscopy times were the averages in our institution over a two-year period. When an I.I. system was used, the average ESD during UGI examination were 126.8 mGy fluoroscopy dose and 11.62 mGy imaging dose, for an average total dose of 138.42 mGy per examination. ESD during barium enema averaged 201.73 mGy fluoroscopy dose and 45.2 mGy imaging dose, for an average total dose of 246.92 mGy per examination. When an FPD system was used, the average ESD during UGI examination were 58.71 mGy fluoroscopy dose and 5.72 mGy imaging dose, for an average total dose of 64.43 mGy per examination. ESD during barium enema averaged 112.21 mGy fluoroscopy dose and 24.55 mGy imaging dose, for an average total dose of 136.76 mGy per examination. The use of an FPD system reduced both fluoroscopy dose and imaging dose by 50%. The number of TV systems equipped with FPD in Japan has increased from around 1300 in 2006 to around 1700 in 2007. The use of FPD systems can be expected to increase in future. This

  14. Source strength verification and quality assurance of preloaded brachytherapy needles using a CMOS flat panel detector

    Energy Technology Data Exchange (ETDEWEB)

    Golshan, Maryam, E-mail: maryam.golshan@bccancer.bc.ca [Department of Physics, University of British Columbia, Vancouver, British Columbia V6T1Z1, Canada and Department of Medical Physics, Vancouver Center, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4E6 (Canada); Spadinger, Ingrid [Department of Medical Physics, Vancouver Center, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4E6 (Canada); Chng, Nick [Department of Medical Physics, Center for the North, British Columbia Cancer Agency, Prince George, British Columbia V2M 7E9 (Canada)

    2016-06-15

    Purpose: Current methods of low dose rate brachytherapy source strength verification for sources preloaded into needles consist of either assaying a small number of seeds from a separate sample belonging to the same lot used to load the needles or performing batch assays of a subset of the preloaded seed trains. Both of these methods are cumbersome and have the limitations inherent to sampling. The purpose of this work was to investigate an alternative approach that uses an image-based, autoradiographic system capable of the rapid and complete assay of all sources without compromising sterility. Methods: The system consists of a flat panel image detector, an autoclavable needle holder, and software to analyze the detected signals. The needle holder was designed to maintain a fixed vertical spacing between the needles and the image detector, and to collimate the emissions from each seed. It also provides a sterile barrier between the needles and the imager. The image detector has a sufficiently large image capture area to allow several needles to be analyzed simultaneously.Several tests were performed to assess the accuracy and reproducibility of source strengths obtained using this system. Three different seed models (Oncura 6711 and 9011 {sup 125}I seeds, and IsoAid Advantage {sup 103}Pd seeds) were used in the evaluations. Seeds were loaded into trains with at least 1 cm spacing. Results: Using our system, it was possible to obtain linear calibration curves with coverage factor k = 1 prediction intervals of less than ±2% near the centre of their range for the three source models. The uncertainty budget calculated from a combination of type A and type B estimates of potential sources of error was somewhat larger, yielding (k = 1) combined uncertainties for individual seed readings of 6.2% for {sup 125}I 6711 seeds, 4.7% for {sup 125}I 9011 seeds, and 11.0% for Advantage {sup 103}Pd seeds. Conclusions: This study showed that a flat panel detector dosimetry system

  15. Calibration model of a dual gain flat panel detector for 2D and 3D x-ray imaging

    International Nuclear Information System (INIS)

    Schmidgunst, C.; Ritter, D.; Lang, E.

    2007-01-01

    The continuing research and further development in flat panel detector technology have led to its integration into more and more medical x-ray systems for two-dimensional (2D) and three-dimensional (3D) imaging, such as fixed or mobile C arms. Besides the obvious advantages of flat panel detectors, like the slim design and the resulting optimum accessibility to the patient, their success is primarily a product of the image quality that can be achieved. The benefits in the physical and performance-related features as opposed to conventional image intensifier systems (e.g., distortion-free reproduction of imaging information or almost linear signal response over a large dynamic range) can be fully exploited, however, only if the raw detector images are correctly calibrated and postprocessed. Previous procedures for processing raw data contain idealizations that, in the real world, lead to artifacts or losses in image quality. Thus, for example, temperature dependencies or changes in beam geometry, as can occur with mobile C arm systems, have not been taken into account up to this time. Additionally, adverse characteristics such as image lag or aging effects have to be compensated to attain the best possible image quality. In this article a procedure is presented that takes into account the important dependencies of the individual pixel sensitivity of flat panel detectors used in 2D or 3D imaging and simultaneously minimizes the work required for an extensive recalibration. It is suitable for conventional detectors with only one gain mode as well as for the detectors specially developed for 3D imaging with dual gain read-out technology

  16. Performance Study of an aSi Flat Panel Detector for Fast Neutron Imaging of Nuclear Waste

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, M.; Mauerhofer, E. [Institute of Energy and Climate Research - Nuclear Waste Management and Reactor Safety, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Engels, R.; Kemmerling, G. [Central Institute for Engineering, Electronics and Analytics - Electronic Systems, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Frank, M. [MATHCCES - Department of Mathematics, RWTH Aachen University, 52062 Aachen (Germany); Havenith, A.; Kettler, J.; Klapdor-Kleingrothaus, T. [Institute of Nuclear Engineering and Technology Transfer, RWTH Aachen University, 52062 Aachen (Germany); Schitthelm, O. [Corporate Technology, Siemens AG, 91058 Erlangen (Germany)

    2015-07-01

    Radioactive waste must be characterized to check its conformance for intermediate storage and final disposal according to national regulations. For the determination of radio-toxic and chemo-toxic contents of radioactive waste packages non-destructive analytical techniques are preferentially used. Fast neutron imaging is a promising technique to assay large and dense items providing, in complementarity to photon imaging, additional information on the presence of structures in radioactive waste packages. Therefore the feasibility of a compact Neutron Imaging System for Radioactive waste Analysis (NISRA) using 14 MeV neutrons is studied in a cooperation framework of Forschungszentrum Juelich GmbH, RWTH Aachen University and Siemens AG. However due to the low neutron emission of neutron generators in comparison to research reactors the challenging task resides in the development of an imaging detector with a high efficiency, a low sensitivity to gamma radiation and a resolution sufficient for the purpose. The setup is composed of a commercial D-T neutron generator (Genie16GT, Sodern) with a surrounding shielding made of polyethylene, which acts as a collimator and an amorphous silicon flat panel detector (aSi, 40 x 40 cm{sup 2}, XRD-1642, Perkin Elmer). Neutron detection is achieved using a general propose plastic scintillator (EJ-260, Eljen Technology) linked to the detector. The thermal noise of the photodiodes is reduced by employing an entrance window made of aluminium. Optimal gain and integration time for data acquisition are set by measuring the response of the detector to the radiation of a 500 MBq {sup 241}Am-source. Detector performance was studied by recording neutron radiography images of materials with various, but well known, chemical compositions, densities and dimensions (Al, C, Fe, Pb, W, concrete, polyethylene, 5 x 8 x 10 cm{sup 3}). To simulate gamma-ray emitting waste radiographs in presence of a gamma-ray sources ({sup 60}Co, {sup 137}Cs, {sup 241

  17. Preliminary performance of image quality for a low-dose C-arm CT system with a flat-panel detector

    Energy Technology Data Exchange (ETDEWEB)

    Kyung Cha, Bo [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Seo, Chang-Woo [Department of Radiation Convergence Engineering, College of Health Science, Yonsei University, Wonju (Korea, Republic of); Yang, Keedong [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Jeon, Seongchae, E-mail: sarim@keri.re.kr [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of); Huh, Young [Advanced Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

    2015-06-01

    Digital flat panel imager (FPI)-based cone-beam computed tomography (CBCT) has been widely used in C-arm imaging for spine surgery and interventional procedures. The system provides real-time fluoroscopy with high spatial resolution and three-dimensional (3D) visualization of anatomical structure without the need for patient transportation in interventional suite. In this work, a prototype CBCT imaging platform with continuous single rotation about the gantry was developed by using a large-area flat-panel detector with amorphous Si-based thin film transistor matrix. The different 2D projection images were acquired during constant gantry velocity for reconstructed images at a tube voltage of 80–120 kVp, and different current (10–50 mA) conditions. Various scan protocols were applied to a chest phantom human by changing the number of projection images and scanning angles. The projections were then reconstructed into a volumetric data of sections by using a 3D reconstruction algorithm (e.g., filtered back projection). The preliminary quantitative X-ray performance of our CBCT system was investigated by using the American Association of Physicists in Medicine CT phantom in terms of spatial resolution, contrast resolution, and CT number linearity for mobile or fixed C-arm based CBCT application with limited rotational geometry. The novel results of the projection data with different scanning angles and angular increments in the orbital gantry platform were acquired and evaluated experimentally.

  18. Preliminary performance of image quality for a low-dose C-arm CT system with a flat-panel detector

    International Nuclear Information System (INIS)

    Kyung Cha, Bo; Seo, Chang-Woo; Yang, Keedong; Jeon, Seongchae; Huh, Young

    2015-01-01

    Digital flat panel imager (FPI)-based cone-beam computed tomography (CBCT) has been widely used in C-arm imaging for spine surgery and interventional procedures. The system provides real-time fluoroscopy with high spatial resolution and three-dimensional (3D) visualization of anatomical structure without the need for patient transportation in interventional suite. In this work, a prototype CBCT imaging platform with continuous single rotation about the gantry was developed by using a large-area flat-panel detector with amorphous Si-based thin film transistor matrix. The different 2D projection images were acquired during constant gantry velocity for reconstructed images at a tube voltage of 80–120 kVp, and different current (10–50 mA) conditions. Various scan protocols were applied to a chest phantom human by changing the number of projection images and scanning angles. The projections were then reconstructed into a volumetric data of sections by using a 3D reconstruction algorithm (e.g., filtered back projection). The preliminary quantitative X-ray performance of our CBCT system was investigated by using the American Association of Physicists in Medicine CT phantom in terms of spatial resolution, contrast resolution, and CT number linearity for mobile or fixed C-arm based CBCT application with limited rotational geometry. The novel results of the projection data with different scanning angles and angular increments in the orbital gantry platform were acquired and evaluated experimentally

  19. High resolution X-ray imaging of bone-implant interface by large area flat-panel detector

    International Nuclear Information System (INIS)

    Kytyr, D; Jirousek, O; Dammer, J

    2011-01-01

    The aim of the research was to investigate the cemented bone-implant interface behavior (cement layer degradation and bone-cement interface debonding) with emphasis on imaging techniques suitable to detect the early defects in the cement layer. To simulate in vivo conditions a human pelvic bone was implanted with polyurethane acetabular cup using commercial acrylic bone cement. The implanted cup was then loaded in a custom hip simulator to initiate fatigue crack propagation in the bone cement. The pelvic bone was then repetitively scanned in a micro-tomography device. Reconstructed tomography images showed failure processes that occurred in the cement layer during the first 250,000 cycles. A failure in cemented acetabular implant - debonding, crumbling and smeared cracks - has been found to be at the bone-cement interface. Use of micro-focus source and high resolution flat panel detector of large physical dimensions allowed to reconstruct the micro-structural models suitable for investigation of migration, micro-motions and consecutive loosening of the implant. The large area flat panel detector with physical dimensions 120 x 120mm with 50μm pixel size provided a superior image quality compared to clinical CT systems with 300-150μm pixel size.

  20. Radiography of the chest and upper airway

    International Nuclear Information System (INIS)

    Sharko, G.A.; Wilmot, D.M.

    1987-01-01

    The techniques of radiography of the chest in all pediatric-age groups differ only slightly from those used in adult radiography. The technologist's principal challenge, however, relates to optimum handling of the patient with respect to positioning and radiation protection. The hints provided in this chapter should permit the conscientious radiographer to obtain high quality radiographs on all pediatric patients

  1. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    International Nuclear Information System (INIS)

    Lee, D.; Kim, D.; Choi, S.; Kim, H.-J.; Choi, S.; Lee, H.

    2017-01-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  2. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    Science.gov (United States)

    Lee, D.; Choi, S.; Lee, H.; Kim, D.; Choi, S.; Kim, H.-J.

    2017-04-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  3. Radiation dose reduction using a CdZnTe-based computed tomography system: Comparison to flat-panel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Le, Huy Q.; Ducote, Justin L.; Molloi, Sabee [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2010-03-15

    Purpose: Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detector materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. Methods: A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. Results: The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam

  4. Radiation dose reduction using a CdZnTe-based computed tomography system: Comparison to flat-panel detectors

    International Nuclear Information System (INIS)

    Le, Huy Q.; Ducote, Justin L.; Molloi, Sabee

    2010-01-01

    Purpose: Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detector materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. Methods: A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. Results: The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam

  5. Digital luminescent radiography: A substitute for conventional chest radiography?

    International Nuclear Information System (INIS)

    Neufang, K.F.R.; Krug, B.; Lorenz, R.; Steinbrich, W.

    1990-01-01

    The image quality of digital luminescent radiography (DLR) is sufficient for routine biplane chest radiography and for follow-up studies of heart size, pulmonary congestion, coin lesions, infiltrations, atelectasis, pleural effusions, and mediastinal and hilar lymph node enlargement. Chest radiography in the intensive care unit may in most cases be performed using the DLR technique. there is no need for repeat shots because of incorrect exposure, and the position of catheters, tubes, pacemakers, drains and artificial heart valves, the mediastinum, and the retrocardiac areas of the left lung are more confidently assessed on the edge-enhanced DLR films than on conventional films. Nevertheless, DLR is somewhat inferior to conventional film-screen radiography of the chest as it can demonstrate or rule out subtle pulmonary interstitial disease less confidently. There is no reduction of radiation exposure of the chest in DLR compared with modern film-screen systems. As a consequence, DLR is presently not in a position to replace traditional film-screen radiography of the chest completely. (orig.) [de

  6. Cone-Beam CT with Flat-Panel-Detector Digital Angiography System: Early Experience in Abdominal Interventional Procedures

    International Nuclear Information System (INIS)

    Hirota, Shozo; Nakao, Norio; Yamamoto, Satoshi; Kobayashi, Kaoru; Maeda, Hiroaki; Ishikura, Reiichi; Miura, Koui; Sakamoto, Kiyoshi; Ueda, Ken; Baba, Rika

    2006-01-01

    We developed a cone-beam computed tomography (CBCT) system equipped with a large flat-panel detector. Data obtained by 200 o rotation imaging are reconstructed by means of CBCT to generate three-dimensional images. We report the use of CBCT angiography using CBCT in 10 patients with 8 liver malignancies and 2 hypersplenisms during abdominal interventional procedures. CBCT was very useful for interventional radiologists to confirm a perfusion area of the artery catheter wedged on CT by injection of contrast media through the catheter tip, although the image quality was slightly degraded, scoring as 2.60 on average by streak artifacts. CBCT is space-saving because it does not require a CT system with a gantry, and it is also time-saving because it does not require the transfer of patients

  7. Algorithm for optimisation of paediatric chest radiography

    International Nuclear Information System (INIS)

    Kostova-Lefterova, D.

    2016-01-01

    The purpose of this work is to assess the current practice and patient doses in paediatric chest radiography in a large university hospital. The X-ray unit is used in the paediatric department for respiratory diseases. Another purpose was to recommend and apply optimized protocols to reduce patient dose while maintaining diagnostic image quality for the x-ray images. The practice of two different radiographers was studied. The results were compared with the existing practice in paediatric chest radiography and the opportunities for optimization were identified in order to reduce patient doses. A methodology was developed for optimization of the x-ray examinations by grouping children in age groups or according to other appropriate indication and creating an algorithm for proper selection of the exposure parameters for each group. The algorithm for the optimisation of paediatric chest radiography reduced patient doses (PKA, organ dose, effective dose) between 1.5 and 6 times for the different age groups, the average glandular dose up to 10 times and the dose for the lung between 2 and 5 times. The resulting X-ray images were of good diagnostic quality. The subjectivity in the choice of exposure parameters was reduced and standardization has been achieved in the work of the radiographers. The role of the radiologist, the medical physicist and radiographer in the process of optimization was shown. It was proven the effect of teamwork in reducing patient doses at keeping adequate image quality. Key words: Chest Radiography. Paediatric Radiography. Optimization. Radiation Exposure. Radiation Protection

  8. Investigation on effect of image lag in fluoroscopic images obtained with a dynamic flat-panel detector (FPD) on accuracy of target tracking in radiotherapy

    International Nuclear Information System (INIS)

    Tanaka, Rie; Ichikawa, Katsuhiro; Sanada, Sigeru; Mori, Shinichiro; Dobashi, Suguru; Kumagai, Motoki; Minohara, Shinichi; Kawashima, Hiroki

    2010-01-01

    Real-time tumor tracking in external radiotherapy can be achieved by diagnostic (kV) X-ray imaging with a dynamic flat-panel detector (FPD). The purpose of this study was to address image lag in target tracking and its influence on the accuracy of tumor tracking. Fluoroscopic images were obtained using a direct type of dynamic FPD. Image lag properties were measured without test devices according to IEC 62220-1. Modulation transfer function (MTF) and profile curves were measured on the edges of a moving tungsten plate at movement rate of 10 and 20 mm/s, covering lung tumor movement of normal breathing. A lung tumor and metal sphere with blurred edge due to image lag was simulated using the results and then superimposed on breathing chest radiographs of a patient. The moving target with and without image lag was traced using a template-matching technique. In the results, the image lag for the first frame after X-ray cutoff was 2.0% and decreased to less than 0.1% in the fifth frame. In the measurement of profile curves on the edges of static and moving tungsten material plates, the effect of image lag was seen as blurred edges of the plate. The blurred edges of a moving target were indicated as reduction of MTF. However, the target could be traced within an error of ±5 mm. The results indicated that there was no effect of image lag on target tracking in usual breathing speed in a radiotherapy situation. (author)

  9. Satisfaction of Search in Chest Radiography 2015.

    Science.gov (United States)

    Berbaum, Kevin S; Krupinski, Elizabeth A; Schartz, Kevin M; Caldwell, Robert T; Madsen, Mark T; Hur, Seung; Laroia, Archana T; Thompson, Brad H; Mullan, Brian F; Franken, Edmund A

    2015-11-01

    Two decades have passed since the publication of laboratory studies of satisfaction of search (SOS) in chest radiography. Those studies were performed using film. The current investigation tests for SOS effects in computed radiography of the chest. Sixty-four chest computed radiographs half demonstrating various "test" abnormalities were read twice by 20 radiologists, once with and once without the addition of a simulated pulmonary nodule. Receiver-operating characteristic detection accuracy and decision thresholds were analyzed to study the effects of adding the nodule on detecting the test abnormalities. Results of previous studies were reanalyzed using similar modern techniques. In the present study, adding nodules did not influence detection accuracy for the other abnormalities (P = .93), but did induce a reluctance to report them (P chest radiography (P chest radiography has changed, but it is not clear why. SOS may be changing as a function of changes in radiology education and practice. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  10. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

    OpenAIRE

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

    2013-01-01

    Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).

  11. Digital chest radiography: collimation and dose reduction

    DEFF Research Database (Denmark)

    Debess, Jeanne; Johnsen, Karen Kirstine; Vejle-Sørensen, Jens Kristian

    ,3 mAs and SID SID of 180 centimetres using a phantom and lithium fluoride thermo luminescence dosimeter (TLD). Dose to risk organs mamma, thyroid and colon are measured at different collimations with one-centimetre steps. TLD results are used to estimate dose reduction for different collimations...... at the conference. Conclusion: Collimation improvement in basic chest radiography can reduce the radiation to female patients at chest x-ray examinations....

  12. Interpretation of neonatal chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hye Kyung [Dept. of Radiology, Kangwon National University Hospital, Chuncheon (Korea, Republic of)

    2016-05-15

    Plain radiographs for infants in the neonatal intensive care unit are obtained using the portable X-ray equipment in order to evaluate the neonatal lungs and also to check the position of the tubes and catheters used for monitoring critically-ill neonates. Neonatal respiratory distress is caused by a variety of medical or surgical disease conditions. Clinical information about the gestational week, respiratory symptoms, and any events during delivery is essential for interpretation of the neonatal chest radiographs. Awareness of common chest abnormality in the prematurely born or term babies is also very important for chest evaluation in the newborn. Furthermore, knowledge about complications such as air leaks and bronchopulmonary dysplasia following treatment are required to accurately inform the clinicians. The purpose of this article was to briefly review radiographic findings of chest diseases in newborns that are relatively common in daily practice.

  13. Interpretation of neonatal chest radiography

    International Nuclear Information System (INIS)

    Yoon, Hye Kyung

    2016-01-01

    Plain radiographs for infants in the neonatal intensive care unit are obtained using the portable X-ray equipment in order to evaluate the neonatal lungs and also to check the position of the tubes and catheters used for monitoring critically-ill neonates. Neonatal respiratory distress is caused by a variety of medical or surgical disease conditions. Clinical information about the gestational week, respiratory symptoms, and any events during delivery is essential for interpretation of the neonatal chest radiographs. Awareness of common chest abnormality in the prematurely born or term babies is also very important for chest evaluation in the newborn. Furthermore, knowledge about complications such as air leaks and bronchopulmonary dysplasia following treatment are required to accurately inform the clinicians. The purpose of this article was to briefly review radiographic findings of chest diseases in newborns that are relatively common in daily practice

  14. Noise, sampling, and the number of projections in cone-beam CT with a flat-panel detector

    International Nuclear Information System (INIS)

    Zhao, Z.; Gang, G. J.; Siewerdsen, J. H.

    2014-01-01

    Purpose: To investigate the effect of the number of projection views on image noise in cone-beam CT (CBCT) with a flat-panel detector. Methods: This fairly fundamental consideration in CBCT system design and operation was addressed experimentally (using a phantom presenting a uniform medium as well as statistically motivated “clutter”) and theoretically (using a cascaded systems model describing CBCT noise) to elucidate the contributing factors of quantum noise (σ Q ), electronic noise (σ E ), and view aliasing (σ view ). Analysis included investigation of the noise, noise-power spectrum, and modulation transfer function as a function of the number of projections (N proj ), dose (D tot ), and voxel size (b vox ). Results: The results reveal a nonmonotonic relationship between image noise andN proj at fixed total dose: for the CBCT system considered, noise decreased with increasing N proj due to reduction of view sampling effects in the regime N proj proj due to increased electronic noise. View sampling effects were shown to depend on the heterogeneity of the object in a direct analytical relationship to power-law anatomical clutter of the form κ/f  β —and a general model of individual noise components (σ Q , σ E , and σ view ) demonstrated agreement with measurements over a broad range in N proj , D tot , and b vox . Conclusions: The work elucidates fairly basic elements of CBCT noise in a manner that demonstrates the role of distinct noise components (viz., quantum, electronic, and view sampling noise). For configurations fairly typical of CBCT with a flat-panel detector (FPD), the analysis reveals a “sweet spot” (i.e., minimum noise) in the rangeN proj ∼ 250–350, nearly an order of magnitude lower in N proj than typical of multidetector CT, owing to the relatively high electronic noise in FPDs. The analysis explicitly relates view aliasing and quantum noise in a manner that includes aspects of the object (“clutter”) and imaging chain

  15. Method of estimating patient skin dose from dose displayed on medical X-ray equipment with flat panel detector

    International Nuclear Information System (INIS)

    Fukuda, Atsushi; Koshida, Kichiro; Togashi, Atsuhiko; Matsubara, Kousuke

    2004-01-01

    The International Electrotechnical Commission (IEC) has stipulated that medical X-ray equipment for interventional procedures must display radiation doses such as air kerma in free air at the interventional reference point and dose area product to establish radiation safety for patients (IEC 60601-2-43). However, it is necessary to estimate entrance skin dose for the patient from air kerma for an accurate risk assessment of radiation skin injury. To estimate entrance skin dose from displayed air kerma in free air at the interventional reference point, it is necessary to consider effective energy, the ratio of the mass-energy absorption coefficient for skin and air, and the backscatter factor. In addition, since automatic exposure control is installed in medical X-ray equipment with flat panel detectors, it is necessary to know the characteristics of control to estimate exposure dose. In order to calculate entrance skin dose under various conditions, we investigated clinical parameters such as tube voltage, tube current, pulse width, additional filter, and focal spot size, as functions of patient body size. We also measured the effective energy of X-ray exposure for the patient as a function of clinical parameter settings. We found that the conversion factor from air kerma in free air to entrance skin dose is about 1.4 for protection. (author)

  16. Aging of imaging properties of a CMOS flat-panel detector for dental cone-beam computed tomography

    Science.gov (United States)

    Kim, D. W.; Han, J. C.; Yun, S.; Kim, H. K.

    2017-01-01

    We have experimentally investigated the long-term stability of imaging properties of a flat-panel detector in conditions used for dental x-ray imaging. The detector consists of a CsI:Tl layer and CMOS photodiode pixel arrays. Aging simulations were carried out using an 80-kVp x-ray beam at an air-kerma rate of approximately 5 mGy s-1 at the entrance surface of the detector with a total air kerma of up to 0.6 kGy. Dark and flood-field images were periodically obtained during irradiation, and the mean signal and noise levels were evaluated for each image. We also evaluated the modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). The aging simulation showed a decrease in both the signal and noise of the gain-offset-corrected images, but there was negligible change in the signal-to-noise performance as a function of the accumulated dose. The gain-offset correction for analyzing images resulted in negligible changes in MTF, NPS, and DQE results over the total dose. Continuous x-ray exposure to a detector can cause degradation in the physical performance factors such the detector sensitivity, but linear analysis of the gain-offset-corrected images can assure integrity of the imaging properties of a detector during its lifetime.

  17. Improving screen-film chest radiography

    International Nuclear Information System (INIS)

    Shaikh, N.; Baker, R.A.

    1996-01-01

    Traditionally symmetric screens and double emulsion symmetric films with medium to wide latitutde are used for radiography of the chest. Beacuse of mismatch of transmitted exposure through the chest with limited latitude of the film, most of the dense areas of the chest are underexposed. Kodak's recent innovation of a unique asymmetry screen-film system (InSight) alleviates this problem. Our phantom measurement indicates that the InSight system offers wider recording range, and the flexible grid permits more positional latitude than conventional grids. Our five-year extensive clinical experience indicates that dense anatomic structures, such as mediastinum, retrocardiac and subdiaphragmatic, are more visible in the InSight system than in the conventional symmetric system. Similarly, a substantial improvement in image quality in portable chest imaging is realized by use of flexible grids because of scatter rejection and invisible grid lines. (author)

  18. Evaluation the image obtained from X-ray flat-panel detectors utilizing a polycrystalline CdZnTe film as the conversion layer

    International Nuclear Information System (INIS)

    Tokuda, S.; Kishihara, H.; Kaino, M.; Sato, T.

    2006-01-01

    We can expect that fluoroscopic images with a high sensitivity and excellent detective efficiency can be obtained by using a semiconductor with a small W factor for the conversion layer of X-ray flat-panel detectors, which have experienced a rapid gain inpopularity for medical and non-destructive industrial inspection uses in recent years. We believe that polycrystalline CdZnTe film formed by the closed spaced sublimation (CSS) method is a promising conversion material for next-generation high efficiency X-ray flat-panel detectors, and have previously reported the results of feasibility studies. In this paper, we present an overview of X-ray flat-panel detectors and the features of CdZnTe film, then we describe the CSS method of deposition and evaluation of the physical characteristics of CdZnTe film, and finally we present the results of our fabrication and testing of proto-type detectors utilizing CdZnTe film. (author)

  19. Percutaneous sacroplasty with the use of C-arm flat-panel detector CT: technical feasibility and clinical outcome

    International Nuclear Information System (INIS)

    Kang, Sung Eun; Lee, Joon Woo; Kim, Joo Hyung; Kang, Heung Sik; Park, Kun Woo; Yeom, Jin S.

    2011-01-01

    Sacroplasty for sacral insufficiency fractures (SIFs) has been performed mostly under computed tomography (CT) or fluoroscopy guidance. The purposes of this study are to describe technical tips and clinical outcomes of sacroplasty under C-arm flat panel detector CT (C-arm CT) guidance, and to compare the cement distributions shown on C-arm CT with those on multi-detector CT (MDCT). This study consisted of patients who underwent sacroplasty for SIF using C-arm CT from May 2006 to May 2009. Technical success was assessed in terms of cement filling and leakage. Clinical outcome was assessed at short-term (less than 1 month) and long-term (more than 1 month) follow-up using a four-grade patient satisfaction scale: poor, fair, good, and excellent. After sacroplasty, all patients underwent MDCT and three radiologists compared MDCT images with C-arm CT images in consensus, focusing on the cement distribution and cement leakage. Sacroplasties were performed on both sacral alae in all 8 patients (male:female = 2:6, mean age = 76.9, range = 63-82). The technical success rate was 100%. At short-term follow up, 6 patients (87.5%) reported significant improvement. Five patients (62.5%) were available for long-term follow-up and all 5 patients reported a reduced pain and an improved ability to ambulate. Using MDCT as the standard of reference, the cement distribution was visualized equally well by C-arm CT. Sacroplasty under C-arm CT showed excellent technical success and good clinical outcome. There was an excellent correlation between C-arm CT and MDCT in evaluating cement distribution and cement leakage. (orig.)

  20. Percutaneous sacroplasty with the use of C-arm flat-panel detector CT: technical feasibility and clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung Eun; Lee, Joon Woo; Kim, Joo Hyung; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology, Gyeonggi-do (Korea, Republic of); Park, Kun Woo; Yeom, Jin S. [Seoul National University Bundang Hospital, Department of Orthopaedic Surgery, Gyeonggi-do (Korea, Republic of)

    2011-04-15

    Sacroplasty for sacral insufficiency fractures (SIFs) has been performed mostly under computed tomography (CT) or fluoroscopy guidance. The purposes of this study are to describe technical tips and clinical outcomes of sacroplasty under C-arm flat panel detector CT (C-arm CT) guidance, and to compare the cement distributions shown on C-arm CT with those on multi-detector CT (MDCT). This study consisted of patients who underwent sacroplasty for SIF using C-arm CT from May 2006 to May 2009. Technical success was assessed in terms of cement filling and leakage. Clinical outcome was assessed at short-term (less than 1 month) and long-term (more than 1 month) follow-up using a four-grade patient satisfaction scale: poor, fair, good, and excellent. After sacroplasty, all patients underwent MDCT and three radiologists compared MDCT images with C-arm CT images in consensus, focusing on the cement distribution and cement leakage. Sacroplasties were performed on both sacral alae in all 8 patients (male:female = 2:6, mean age = 76.9, range = 63-82). The technical success rate was 100%. At short-term follow up, 6 patients (87.5%) reported significant improvement. Five patients (62.5%) were available for long-term follow-up and all 5 patients reported a reduced pain and an improved ability to ambulate. Using MDCT as the standard of reference, the cement distribution was visualized equally well by C-arm CT. Sacroplasty under C-arm CT showed excellent technical success and good clinical outcome. There was an excellent correlation between C-arm CT and MDCT in evaluating cement distribution and cement leakage. (orig.)

  1. A new system for fully automatic inspection of digital flat-panel detector radiographs of aluminium castings

    International Nuclear Information System (INIS)

    Fuchs, T.; Hassler, U.; Huetten, U.; Wenzel, T.

    2006-01-01

    The aim of our work was the integration of various newly-developed methods into a system for fully automatic radioscopic inspection of arbitrary casting parts. Using a 16-bit flat-panel detector, projections in arbitrary directions through the part are acquired and analysed. The software tool for inspection can be separated into five stages: registration, calibration, image processing, fault segmentation, and quality assessment. Thereby, each step is realized with full 16-bit data processing. Within the first processing stage, information about the physical length and density of the aluminium structures is extracted from the primary projections. Next, the primary image is registered with a reference image, which was acquired previously. Afterwards, the third stage combines both reference image-based and reference-less testing. A filter is applied, which adapts automatically to the local object structure by referring to the properties of the reference. Thereby, the self-adapting filter selects its size, direction and filter method optimally according to the local situation. Similar to the reference-less procedure, a subtraction is followed by a threshold operation, resulting in a map of regions that are suspected to be faulty. The fourth step aims at an elimination of false-positive detections. Again, two methods are applied successively: evaluation of local image features at suspicious positions and a classification based on teachings independent of position and orientation of the faults. Within the last step the quality criteria are applied. These criteria may concern fault size and depth, the density of faults in critical regions and a minimum distance between two or more faults. (orig.)

  2. Bacteriological research for the contamination of equipment in chest radiography

    International Nuclear Information System (INIS)

    Choi, Seung Gu; Song, Woon Heung; Kweon, Dae Cheol

    2015-01-01

    The purpose is to determine the degree of contamination of the equipment for infection control in chest radiography of the radiology department. We confirmed by chemical and bacterial identification of bacteria of the equipment and established a preventive maintenance plan. Chest X-ray radiography contact area on the instrument patients shoulder, hand, chin, chest lateral radiography patient contact areas with a 70% isopropyl alcohol cotton swab were compared to identify the bacteria before and after sterilization on the patient contact area in the chest radiography equipment of the department. The gram positive Staphylococcus was isolated from side shoots handle before disinfection in the chest radiography equipment. For the final identification of antibiotic tested that it was determined by performing the nobobiocin to the sensitive Staphylococcus epidermidis. Chest radiography equipment before disinfecting the handle side of Staphylococcus epidermidis bacteria were detected using a disinfectant should be to prevent hospital infections

  3. Bacteriological research for the contamination of equipment in chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seung Gu; Song, Woon Heung; Kweon, Dae Cheol [Shinhan University, Uijeongbu (Korea, Republic of)

    2015-12-15

    The purpose is to determine the degree of contamination of the equipment for infection control in chest radiography of the radiology department. We confirmed by chemical and bacterial identification of bacteria of the equipment and established a preventive maintenance plan. Chest X-ray radiography contact area on the instrument patients shoulder, hand, chin, chest lateral radiography patient contact areas with a 70% isopropyl alcohol cotton swab were compared to identify the bacteria before and after sterilization on the patient contact area in the chest radiography equipment of the department. The gram positive Staphylococcus was isolated from side shoots handle before disinfection in the chest radiography equipment. For the final identification of antibiotic tested that it was determined by performing the nobobiocin to the sensitive Staphylococcus epidermidis. Chest radiography equipment before disinfecting the handle side of Staphylococcus epidermidis bacteria were detected using a disinfectant should be to prevent hospital infections.

  4. Reduction of ring artifacts in CBCT: Detection and correction of pixel gain variations in flat panel detectors

    International Nuclear Information System (INIS)

    Altunbas, Cem; Lai, Chao-Jen; Zhong, Yuncheng; Shaw, Chris C.

    2014-01-01

    Purpose: In using flat panel detectors (FPD) for cone beam computed tomography (CBCT), pixel gain variations may lead to structured nonuniformities in projections and ring artifacts in CBCT images. Such gain variations can be caused by change in detector entrance exposure levels or beam hardening, and they are not accounted by conventional flat field correction methods. In this work, the authors presented a method to identify isolated pixel clusters that exhibit gain variations and proposed a pixel gain correction (PGC) method to suppress both beam hardening and exposure level dependent gain variations. Methods: To modulate both beam spectrum and entrance exposure, flood field FPD projections were acquired using beam filters with varying thicknesses. “Ideal” pixel values were estimated by performing polynomial fits in both raw and flat field corrected projections. Residuals were calculated by taking the difference between measured and ideal pixel values to identify clustered image and FPD artifacts in flat field corrected and raw images, respectively. To correct clustered image artifacts, the ratio of ideal to measured pixel values in filtered images were utilized as pixel-specific gain correction factors, referred as PGC method, and they were tabulated as a function of pixel value in a look-up table. Results: 0.035% of detector pixels lead to clustered image artifacts in flat field corrected projections, where 80% of these pixels were traced back and linked to artifacts in the FPD. The performance of PGC method was tested in variety of imaging conditions and phantoms. The PGC method reduced clustered image artifacts and fixed pattern noise in projections, and ring artifacts in CBCT images. Conclusions: Clustered projection image artifacts that lead to ring artifacts in CBCT can be better identified with our artifact detection approach. When compared to the conventional flat field correction method, the proposed PGC method enables characterization of nonlinear

  5. Revisit image control for pediatric chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kohda, Ehiichi; Nagamoto, Masashi; Gomi, Tatsuya; Terada, Hitoshi; Kawawa, Yohko [Toho Univ., School of Medicine, Tokyo (Japan); Tsutsumi, Yoshiyuki; Masaki, Hidekazu [National Center for Child Health and Development, Tokyo (Japan); Shiraga, Nobuyuki [Kyousai Tachikawa Hospital, Tachikawa, Tokyo (Japan)

    2007-02-15

    The aim of this study was to analyze the fraction defectiveness and efficacy of the patient immobilization device (PID) for pediatric chest radiography. We examined 840 plain chest radiographs in six hospitals, including four children's hospitals and two general hospitals. The mean age of the patients was 1.9 years (range 0-5 years). Two boardqualified pediatric radiologists rated (into three grades, by consensus) the degree of inspiration, rotation, lordosis, scoliosis, and cutoff or coning as well as the quality of the chest radiographs. The incidence of ''poor'' and ''very poor'' quality examinations was 2/140 and 3/140 in each of two children's hospitals using PID. The corresponding figures were 9/139 and 17/140 in the two children's hospitals that did not use PID. The general hospital using PID had 14/140 ''poor'' and ''very poor'' examinations. The general hospital that did not use PID had 28/140 ''poor'' and ''very poor'' examinations. Thus, statistically better quality chest radiography was obtained with the use of PID (P<0.001). Likewise, rotation, lordosis, and scoliosis were less frequently diagnosed as present when PID was used (P<0.001, 0.001, 0.05). Cutoff or coning had no relation to the use of PID (P=0.13). No significant difference was found between the degree of inspiration and the use of PID (P=0.56). Fraction defectiveness in the general hospital that did not use PID was as much as 14 times higher than that of the children's hospitals that used PID. The patient immobilization device is recommended for hospitals with technologists not specifically trained for pediatric examination. (author)

  6. Revisit image control for pediatric chest radiography

    International Nuclear Information System (INIS)

    Kohda, Ehiichi; Nagamoto, Masashi; Gomi, Tatsuya; Terada, Hitoshi; Kawawa, Yohko; Tsutsumi, Yoshiyuki; Masaki, Hidekazu; Shiraga, Nobuyuki

    2007-01-01

    The aim of this study was to analyze the fraction defectiveness and efficacy of the patient immobilization device (PID) for pediatric chest radiography. We examined 840 plain chest radiographs in six hospitals, including four children's hospitals and two general hospitals. The mean age of the patients was 1.9 years (range 0-5 years). Two boardqualified pediatric radiologists rated (into three grades, by consensus) the degree of inspiration, rotation, lordosis, scoliosis, and cutoff or coning as well as the quality of the chest radiographs. The incidence of ''poor'' and ''very poor'' quality examinations was 2/140 and 3/140 in each of two children's hospitals using PID. The corresponding figures were 9/139 and 17/140 in the two children's hospitals that did not use PID. The general hospital using PID had 14/140 ''poor'' and ''very poor'' examinations. The general hospital that did not use PID had 28/140 ''poor'' and ''very poor'' examinations. Thus, statistically better quality chest radiography was obtained with the use of PID (P<0.001). Likewise, rotation, lordosis, and scoliosis were less frequently diagnosed as present when PID was used (P<0.001, 0.001, 0.05). Cutoff or coning had no relation to the use of PID (P=0.13). No significant difference was found between the degree of inspiration and the use of PID (P=0.56). Fraction defectiveness in the general hospital that did not use PID was as much as 14 times higher than that of the children's hospitals that used PID. The patient immobilization device is recommended for hospitals with technologists not specifically trained for pediatric examination. (author)

  7. Image processing in digital chest radiography

    International Nuclear Information System (INIS)

    Manninen, H.; Partanen, K.; Lehtovirta, J.; Matsi, P.; Soimakallio, S.

    1992-01-01

    The usefulness of digital image processing of chest radiographs was evaluated in a clinical study. In 54 patients, chest radiographs in the posteroanterior projection were obtained by both 14 inch digital image intensifier equipment and the conventional screen-film technique. The digital radiographs (512x512 image format) viewed on a 625 line monitor were processed in 3 different ways: 1.standard display; 2.digital edge enhancement for the standard display; 3.inverse intensity display. The radiographs were interpreted independently by 3 radiologists. Diagnoses were confirmed by CT, follow-up radiographs and clinical records. Chest abnormalities of the films analyzed included 21 primary lung tumors, 44 pulmonary nodules, 16 cases with mediastinal disease, 17 with pneumonia /atelectasis. Interstitial lung disease, pleural plaques, and pulmonary emphysema were found in 30, 18 and 19 cases respectively. Sensitivity of conventional radiography when averaged overall findings was better than that of digital techniques (P<0.001). Differences in diagnostic accuracy measured by sensitivity and specificity between the 3 digital display modes were small. Standard image display showed better sensitivity for pulmonary nodules (0.74 vs 0.66; P<0.05) but poorer specificity for pulmonary emphysema (0.85 vs 0.93; P<0.05) compared with inverse intensity display. It is concluded that when using 512x512 image format, the routine use of digital edge enhancement and tone reversal at digital chest radiographs is not warranted. (author). 12 refs.; 4 figs.; 2 tabs

  8. Chest radiography: new technological developments and their applications

    NARCIS (Netherlands)

    Schalekamp, S.; Ginneken, B. van; Karssemeijer, N.; Schaefer-Prokop, C.M.

    2014-01-01

    Digital chest radiography is still the most common radiological examination. With the upcoming three-dimensional (3D) acquisition techniques the value of radiography seems to diminish. But because radiography is inexpensive, readily available, and requires very little dose, it is still being used

  9. Reconstruction of Spectra Using X-ray Flat Panel Detector; Reconstruccion de Espectros de Rayos X Utilizando un Detector Flat Panel

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, S.; Querol, A.; Pozuelo, F.; Juste, B.; Rodenas, J.; Verdu, G.

    2013-07-01

    In this work, we used a flat panel detector with a wedge of PMMA for absorbed dose curve for given working conditions of X-ray tube The relationship between absorbed dose curve recorded by the flat panel and primary X-ray spectrum is defined by a response function that can be obtained using the Monte Carlo method, namely the MCNP5 code. However there are some problems that affect the applicability of this method such as: flat panel characteristics and the characteristics of the physical process (ill-conditioned problem). Both aspects are discussed in this paper.

  10. Dual-energy cone-beam CT with a flat-panel detector: Effect of reconstruction algorithm on material classification

    International Nuclear Information System (INIS)

    Zbijewski, W.; Gang, G. J.; Xu, J.; Wang, A. S.; Stayman, J. W.; Taguchi, K.; Carrino, J. A.; Siewerdsen, J. H.

    2014-01-01

    Purpose: Cone-beam CT (CBCT) with a flat-panel detector (FPD) is finding application in areas such as breast and musculoskeletal imaging, where dual-energy (DE) capabilities offer potential benefit. The authors investigate the accuracy of material classification in DE CBCT using filtered backprojection (FBP) and penalized likelihood (PL) reconstruction and optimize contrast-enhanced DE CBCT of the joints as a function of dose, material concentration, and detail size. Methods: Phantoms consisting of a 15 cm diameter water cylinder with solid calcium inserts (50–200 mg/ml, 3–28.4 mm diameter) and solid iodine inserts (2–10 mg/ml, 3–28.4 mm diameter), as well as a cadaveric knee with intra-articular injection of iodine were imaged on a CBCT bench with a Varian 4343 FPD. The low energy (LE) beam was 70 kVp (+0.2 mm Cu), and the high energy (HE) beam was 120 kVp (+0.2 mm Cu, +0.5 mm Ag). Total dose (LE+HE) was varied from 3.1 to 15.6 mGy with equal dose allocation. Image-based DE classification involved a nearest distance classifier in the space of LE versus HE attenuation values. Recognizing the differences in noise between LE and HE beams, the LE and HE data were differentially filtered (in FBP) or regularized (in PL). Both a quadratic (PLQ) and a total-variation penalty (PLTV) were investigated for PL. The performance of DE CBCT material discrimination was quantified in terms of voxelwise specificity, sensitivity, and accuracy. Results: Noise in the HE image was primarily responsible for classification errors within the contrast inserts, whereas noise in the LE image mainly influenced classification in the surrounding water. For inserts of diameter 28.4 mm, DE CBCT reconstructions were optimized to maximize the total combined accuracy across the range of calcium and iodine concentrations, yielding values of ∼88% for FBP and PLQ, and ∼95% for PLTV at 3.1 mGy total dose, increasing to ∼95% for FBP and PLQ, and ∼98% for PLTV at 15.6 mGy total dose. For a

  11. Gain and offset calibration reduces variation in exposure-dependent SNR among systems with identical digital flat-panel detectors.

    Science.gov (United States)

    Willis, Charles E; Vinogradskiy, Yevgeniy Y; Lofton, Brad K; White, R Allen

    2011-07-01

    The conditions under which vendor performance criteria for digital radiography systems are obtained do not adequately simulate the conditions of actual clinical imaging with respect to radiographic technique factors, scatter production, and scatter control. Therefore, the relationship between performance under ideal conditions and performance in clinical practice remains unclear. Using data from a large complement of systems in clinical use, the authors sought to develop a method to establish expected performance criteria for digital flat-panel radiography systems with respect to signal-to-noise ratio (SNR) versus detector exposure under clinical conditions for thoracic imaging. The authors made radiographic exposures of a patient-equivalent chest phantom at 125 kVp and 180 cm source-to-image distance. The mAs value was modified to produce exposures above and below the mAs delivered by automatic exposure control. Exposures measured free-in-air were corrected to the imaging plane by the inverse square law, by the attenuation factor of the phantom, and by the Bucky factor of the grid for the phantom, geometry, and kilovolt peak. SNR was evaluated as the ratio of the mean to the standard deviation (SD) of a region of interest automatically selected in the center of each unprocessed image. Data were acquired from 18 systems, 14 of which were tested both before and after gain and offset calibration. SNR as a function of detector exposure was interpolated using a double logarithmic function to stratify the data into groups of 0.2, 0.5, 1.0, 2.0, and 5.0 mR exposure (1.8, 4.5, 9.0, 18, and 45 microGy air KERMA) to the detector. The mean SNR at each exposure interval after calibration exhibited linear dependence on the mean SNR before calibration (r2=0.9999). The dependence was greater than unity (m = 1.101 +/- 0.006), and the difference from unity was statistically significant (p grid replacement. The nonconformant behavior of the other system was corrected by replacing

  12. Chest tomosynthesis: technical and clinical perspectives.

    Science.gov (United States)

    Johnsson, Ase Allansdotter; Vikgren, Jenny; Bath, Magnus

    2014-02-01

    The recent implementation of chest tomosynthesis is built on the availability of large, dose-efficient, high-resolution flat panel detectors, which enable the acquisition of the necessary number of projection radiographs to allow reconstruction of section images of the chest within one breath hold. A chest tomosynthesis examination obtains the increased diagnostic information provided by volumetric imaging at a radiation dose comparable to that of conventional chest radiography. There is evidence that the sensitivity of chest tomosynthesis may be at least three times higher than for conventional chest radiography for detection of pulmonary nodules. The sensitivity increases with increasing nodule size and attenuation and decreases for nodules with subpleural location. Differentiation between pleural and subpleural lesions is a known pitfall due to the limited depth resolution in chest tomosynthesis. Studies on different types of pathology report increased detectability in favor of chest tomosynthesis in comparison to chest radiography. The technique provides improved diagnostic accuracy and confidence in the diagnosis of suspected pulmonary lesions on chest radiography and facilitates the exclusion of pulmonary lesions in a majority of patients, avoiding the need for computed tomography (CT). However, motion artifacts can be a cumbersome limitation and breathing during the tomosynthesis image acquisition may result in severe artifacts significantly affecting the detectability of pathology. In summary, chest tomosynthesis has been shown to be superior to chest conventional radiography for many tasks and to be able to replace CT in selected cases. In our experience chest tomosynthesis is an efficient problem solver in daily clinical work. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  13. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    Science.gov (United States)

    Abu Anas, Emran Mohammad; Kim, Jae Gon; Lee, Soo Yeol; Kamrul Hasan, Md

    2011-10-01

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  14. Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment.

    Science.gov (United States)

    Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Nikoubashman, Omid; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

    2016-08-01

    Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. MAR improved the assessability of the brain parenchyma and small vessels (diameter metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  15. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    International Nuclear Information System (INIS)

    Anas, Emran Mohammad Abu; Hasan, Md Kamrul; Kim, Jae Gon; Lee, Soo Yeol

    2011-01-01

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  16. The Usefulness of Three-Dimensional Angiography with a Flat Panel Detector of Direct Conversion Type in a Transcatheter Arterial Chemoembolization Procedure for Hepatocellular Carcinoma: Initial Experience

    International Nuclear Information System (INIS)

    Kakeda, Shingo; Korogi, Yukunori; Hatakeyama, Yoshihisa; Ohnari, Norihiro; Oda, Nobuhiro; Nishino, Kazuyoshi; Miyamoto, Wataru

    2008-01-01

    The purpose of this study was to assess the usefulness of a three-dimensional (3D) angiography system using a flat panel detector of direct conversion type in treatments with subsegmental transcatheter arterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). Thirty-six consecutive patients who underwent hepatic angiography were prospectively examined. First, two radiologists evaluated the degree of visualization of the peripheral branches of the hepatic arteries on 3D digital subtraction angiography (DSA). Then the radiologists evaluated the visualization of tumor staining and feeding arteries in 25 patients (30 HCCs) who underwent subsegmental TACE. The two radiologists who performed the TACE assessed whether the additional information provided by 3D DSA was useful for treatments. In 34 (94.4%) of 36 patients, the subsegmental branches of the hepatic arteries were sufficiently visualized. The feeding arteries of HCCs were sufficiently visualized in 28 (93%) of 30 HCCs, whereas tumor stains were sufficiently visualized in 18 (60%). Maximum intensity projection images were significantly superior to volume recording images for visualization of the tumor staining and feeding arteries of HCCs. In 27 (90%) of 30 HCCs, 3D DSA provided additional useful information for subsegmental TACE. The high-quality 3D DSA with flat panel detector angiography system provided a precise vascular road map, which was useful for performing subsegmental TACE .of HCCs

  17. Optical compensation device for chest film radiography

    Science.gov (United States)

    Gould, Robert G.; Hasegawa, Bruce H.; DeForest, Sherman E.; Schmidt, Gregory W.; Hier, Richard G.

    1990-07-01

    Although chest radiography is the most commonly performed radiographic examination and one of the most valuable and cost-effective studies in medicine it suffers from relatively high error rates in both missing pathology and false positive interpretations. Detectability of lung nodules and other structures in underpenetrated regions of the chest film can be improved by both exposure and optical compensation but current compensation systems require major capital cost or a significant change in normal clinical practice. A new optical compensation system called the " Intelligent X-Ray Illuminator" (IXI) automatically and virtually instantaneously generates a patient-specific optical unsharp mask that is projected directly on a radiograph. When a radiograph is placed on the IXI which looks much like a conventional viewbox it acquires a low-resolution electronic image of this film from which the film transmission is derived. The transmission information is inverted and blurred in an image processor to form an unsharp mask which is fed into a spatial light modulator (SLM) placed between a light source and the radiograph. The SLM tailors the viewbox luminance by decreasing illumination to underexposed (i. e. transmissive) areas of the radiograph presenting the observer with an optically unsharp-masked image. The IXI uses the original radiograph and will allow it to be viewed on demand with conventional (uniform illumination. Potentially the IXI could introduce the known beneficial aspects of optical unsharp masking into radiology at low capital

  18. TU-E-217BCD-06: Cone Beam Breast CT with a High Resolution Flat Panel Detector-Improvement of Calcification Visibility.

    Science.gov (United States)

    Shen, Y; Zhong, Y; Lai, C; Wang, T; Shaw, C

    2012-06-01

    To investigate the advantage of a high resolution flat panel detector for improving the visibility of microcalcifications (MCs) in cone beam breast CT Methods: A paraffin cylinder was used to simulate a 100% adipose breast. Calcium carbonate grains, ranging from 125-140 μm to 224 - 250 μm in size, were used to simulate the MCs. Groups of 25 same size MCs were embedded at the phantom center. The phantom was scanned with a bench-top CBCT system at various exposure levels. A 75μm pitch flat panel detector (Dexela 2923, Perkin Elmer) with 500μm thick CsI scintillator plate was used as the high resolution detector. A 194 μm pitch detector (Paxscan 4030CB, Varian Medical Systems) was used for reference. 300 projection images were acquired over 360° and reconstructed. The images were reviewed by 6 readers. The MC visibility was quantified as the fraction of visible MCs and averaged for comparison. The visibility was plotted as a function of the estimated dose level for various MC sizes and detectors. The MTFs and DQEs were measured and compared. For imaging small (200 μm and smaller) MCs, the visibility achieved with the 75μm pitch detector was found to be significantly higher than those achieved with the 194μm pitch detector. For imaging larger MCs, there was little advantage in using the 75μm pitch detector. Using the 75μm pitch detector, MCs as small as 180 μm could be imaged to achieve a visibility of 78% with an isocenter tissue dose of ∼20 mGys versus 62% achieved with the 194 μm pitch detector at the same dose level. It was found that a high pitch flat panel detector had the advantages of extending its imaging capability to higher frequencies thus helping improve the visibility when used to image small MCs. This work was supported in part by grants CA104759, CA13852 and CA124585 from NIH-NCI, a grant EB00117 from NIH-NIBIB, and a subcontract from NIST-ATP. © 2012 American Association of Physicists in Medicine.

  19. Calculation of the Cardiothoracic Ratio from Portable Anteroposterior Chest Radiography

    Science.gov (United States)

    Chon, Sung Bin; Oh, Won Sup; Cho, Jun Hwi; Kim, Sam Soo

    2011-01-01

    Cardiothoracic ratio (CTR), the ratio of cardiac diameter (CD) to thoracic diameter (TD), is a useful screening method to detect cardiomegaly, but is reliable only on posteroanterior chest radiography (chest PA). We performed this cross-sectional 3-phase study to establish reliable CTR from anteroposterior chest radiography (chest AP). First, CDChest PA/CDChest AP ratios were determined at different radiation distances by manipulating chest computed tomography to simulate chest PA and AP. CDChest PA was inferred from multiplying CDChest AP by this ratio. Incorporating this CD and substituting the most recent TDChest PA, we calculated the 'corrected' CTR and compared it with the conventional one in patients who took both the chest radiographies. Finally, its validity was investigated among the critically ill patients who performed portable chest AP. CDChest PA/CDChest AP ratio was {0.00099 × (radiation distance [cm])} + 0.79 (n = 61, r = 1.00, P chest AP with an available previous chest PA. This might help physicians detect congestive cardiomegaly for patients undergoing portable chest AP. PMID:22065900

  20. Chest X ray effective doses estimation in computed radiography

    International Nuclear Information System (INIS)

    Abdalla, Esra Abdalrhman Dfaalla

    2013-06-01

    Conventional chest radiography is technically difficult because of wide in tissue attenuations in the chest and limitations of screen-film systems. Computed radiography (CR) offers a different approach utilizing a photostimulable phosphor. photostimulable phosphors overcome some image quality limitations of chest imaging. The objective of this study was to estimate the effective dose in computed radiography at three hospitals in Khartoum. This study has been conducted in radiography departments in three centres Advanced Diagnostic Center, Nilain Diagnostic Center, Modern Diagnostic Center. The entrance surface dose (ESD) measurement was conducted for quality control of x-ray machines and survey of operators experimental techniques. The ESDs were measured by UNFORS dosimeter and mathematical equations to estimate patient doses during chest X rays. A total of 120 patients were examined in three centres, among them 62 were males and 58 were females. The overall mean and range of patient dosed was 0.073±0.037 (0.014-0.16) mGy per procedure while the effective dose was 3.4±01.7 (0.6-7.0) mSv per procedure. This study compared radiation doses to patients radiographic examinations of chest using computed radiology. The radiation dose was measured in three centres in Khartoum- Sudan. The results of the measured effective dose showed that the dose in chest radiography was lower in computed radiography compared to previous studies.(Author)

  1. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: visibility of simulated microcalcifications.

    Science.gov (United States)

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C

    2013-10-01

    To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150-160, 160-180, and 180-200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200-212 and 212-224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224-250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160-180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat

  2. Evaluation of a Noise Reduction Procedure for Chest Radiography

    Science.gov (United States)

    Fukui, Ryohei; Ishii, Rie; Kodani, Kazuhiko; Kanasaki, Yoshiko; Suyama, Hisashi; Watanabe, Masanari; Nakamoto, Masaki; Fukuoka, Yasushi

    2013-01-01

    Background The aim of this study was to evaluate the usefulness of noise reduction procedure (NRP), a function in the new image processing for chest radiography. Methods A CXDI-50G Portable Digital Radiography System (Canon) was used for X-ray detection. Image noise was analyzed with a noise power spectrum (NPS) and a burger phantom was used for evaluation of density resolution. The usefulness of NRP was evaluated by chest phantom images and clinical chest radiography. We employed the Bureau of Radiological Health Method for scoring chest images while carrying out our observations. Results NPS through the use of NRP was improved compared with conventional image processing (CIP). The results in image quality showed high-density resolution through the use of NRP, so that chest radiography examination can be performed with a low dose of radiation. Scores were significantly higher than for CIP. Conclusion In this study, use of NRP led to a high evaluation in these so we are able to confirm the usefulness of NRP for clinical chest radiography. PMID:24574577

  3. High resolution X-ray imaging of bone-implant interface by large area flat-panel detector

    Czech Academy of Sciences Publication Activity Database

    Kytýř, Daniel; Jiroušek, Ondřej; Dammer, J.

    2011-01-01

    Roč. 6, č. 1 (2011), s. 1038-1043 ISSN 1748-0221 R&D Projects: GA ČR(CZ) GAP105/10/2305 Institutional research plan: CEZ:AV0Z20710524 Keywords : computed radiography * computerized tomography * medical-image reconstruction Subject RIV: JJ - Other Materials Impact factor: 1.869, year: 2011 http://iopscience.iop.org/1748-0221/6/01/C01038

  4. Accuracy of chest radiography versus chest computed tomography in hemodynamically stable patients with blunt chest trauma

    Directory of Open Access Journals (Sweden)

    Chardoli Mojtaba

    2013-12-01

    Full Text Available 【Abstract】 Objective: Thoracic injuries are respon- sible for 25% of deaths of blunt traumas. Chest X-ray (CXR is the first diagnostic method in patients with blunt trauma. The aim of this study was to detect the accuracy of CXR versus chest computed tomograpgy (CT in hemodynami- cally stable patients with blunt chest trauma. Methods: Study was conducted at the emergency department of Sina Hospital from March 2011 to March 2012. Hemodynamically stable patients with at least 16 years of age who had blunt chest trauma were included. All patients underwent the same diagnostic protocol which consisted of physical examination, CXR and CT scan respectively. Results: Two hundreds patients (84% male and 16% female were included with a mean age of (37.9±13.7 years. Chin J Traumatol 2013;16(6:351-354 Rib fracture was the most common finding of CXR (12.5% and CT scan (25.5%. The sensitivity of CXR for hemothorax, thoracolumbar vertebra fractures and rib fractures were 20%, 49% and 49%, respectively. Pneumothorax, foreign body, emphysema, pulmonary contusion, liver hematoma and ster- num fracture were not diagnosed with CXR alone. Conclusion: Applying CT scan as the first-line diag- nostic modality in hemodynamically stable patients with blunt chest trauma can detect pathologies which may change management and outcome. Key words: Radiography; Thoracic injuries; Tomography, X-ray computed

  5. Compton radiography, 2. Clinical significance of Compton radiography of a chest phantom

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, S; Sera, K; Fukuda, H; Shishido, F [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer; Mishina, H

    1977-09-01

    Compton radiography, a tomographic technic with Compton-scattered rays of a monochromatic gamma ray beam, was feasible of tomographing a chest phantom. The result suggested that the technic could be extended to imaging of the lung and the surrounding structures of the chest wall, mediastinum and liver in Compton tomographic mode.

  6. Flat panel detector-based cone beam computed tomography with a circle-plus-two-arcs data acquisition orbit: Preliminary phantom study

    International Nuclear Information System (INIS)

    Ning Ruola; Tang Xiangyang; Conover, David; Yu Rongfeng

    2003-01-01

    Cone beam computed tomography (CBCT) has been investigated in the past two decades due to its potential advantages over a fan beam CT. These advantages include (a) great improvement in data acquisition efficiency, spatial resolution, and spatial resolution uniformity, (b) substantially better utilization of x-ray photons generated by the x-ray tube compared to a fan beam CT, and (c) significant advancement in clinical three-dimensional (3D) CT applications. However, most studies of CBCT in the past are focused on cone beam data acquisition theories and reconstruction algorithms. The recent development of x-ray flat panel detectors (FPD) has made CBCT imaging feasible and practical. This paper reports a newly built flat panel detector-based CBCT prototype scanner and presents the results of the preliminary evaluation of the prototype through a phantom study. The prototype consisted of an x-ray tube, a flat panel detector, a GE 8800 CT gantry, a patient table and a computer system. The prototype was constructed by modifying a GE 8800 CT gantry such that both a single-circle cone beam acquisition orbit and a circle-plus-two-arcs orbit can be achieved. With a circle-plus-two-arcs orbit, a complete set of cone beam projection data can be obtained, consisting of a set of circle projections and a set of arc projections. Using the prototype scanner, the set of circle projections were acquired by rotating the x-ray tube and the FPD together on the gantry, and the set of arc projections were obtained by tilting the gantry while the x-ray tube and detector were at the 12 and 6 o'clock positions, respectively. A filtered backprojection exact cone beam reconstruction algorithm based on a circle-plus-two-arcs orbit was used for cone beam reconstruction from both the circle and arc projections. The system was first characterized in terms of the linearity and dynamic range of the detector. Then the uniformity, spatial resolution and low contrast resolution were assessed using

  7. Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

    International Nuclear Information System (INIS)

    Gruber, Michael; Uffmann, Martin; Weber, Michael; Balassy, Csilla; Schaefer-Prokop, Cornelia; Prokop, Mathias

    2006-01-01

    The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality. (orig.)

  8. Whole body dual X-ray absorptiometry for bone mineral density and body composition using a flat panel detector

    International Nuclear Information System (INIS)

    Dinten, J.M.; Robert-Coutant, C.; Gonon, G.; Bordy, T.

    2003-01-01

    Whole-body dual-energy X-ray absorptiometry (DXA) systems are used for the determination of bone mineral density (BMD) but also for body composition estimates (lean mass and fat mass). The calculation is based on the difference in attenuation of body tissues for a low-energy of about 50 KeV and a high-energy of about 80-100 KeV. The measurement of dual-energy projections allows first to compute to the body composition in the non-bone area, and then to extrapolate the fat / lean ratio of soft tissue into the bone area in order to compute the BMD. Since detectors have limited area, a whole body examination requires a scan of the patient and a reconstruction process in order to build up a large field image from smaller radiographs. This reconstruction process must keep the quantitative value of the radiographs, and avoid any distortion which could be a consequence of the conic acquisition geometry. The cone angle is low (6 at maximum) and the large overlap between radiographs helps to reconstruct an image equivalent with a parallel-beam geometry. Scatter is corrected from the radiographs before reconstruction, as described in a previous paper ('Dual-energy X-rays absorptiometry using a 2D digital radiography detector. Application to bone densitometry', SPIE Medical Imaging 2001, Medical Physics). We have developed an original reconstruction method dedicated to whole-body examinations which will be described. Thanks to the quasi-radiologic quality of the detector, reconstructed images are of very good quality and this makes the measurement of BMD and fat / lean masses easier. (author)

  9. Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures

    Energy Technology Data Exchange (ETDEWEB)

    Peer, Siegfried; Neitzel, Ulrich; Giacomuzzi, Salvatore M.; Pechlaner, Sigurd; KUenzel, Karl Heinz; Peer, Regina; Gassner, Eva; Steingruber, Iris; Gaber, O.; Jaschke, Werner

    2002-04-01

    AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures. Peer, S. et al. (2002)

  10. Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures

    International Nuclear Information System (INIS)

    Peer, Siegfried; Neitzel, Ulrich; Giacomuzzi, Salvatore M.; Pechlaner, Sigurd; KUenzel, Karl Heinz; Peer, Regina; Gassner, Eva; Steingruber, Iris; Gaber, O.; Jaschke, Werner

    2002-01-01

    AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures. Peer, S. et al. (2002)

  11. Non-destructive, preclinical evaluation of root canal anatomy of human teeth with flat-panel detector volume CT (FD-VCT)

    International Nuclear Information System (INIS)

    Heidrich, G.; Hassepass, F.; Dullin, C.; Grabbe, E.; Attin, T.; Hannig, C.

    2005-01-01

    Purpose: Successful endodontic diagnostics and therapy call for adequate depiction of the root canal anatomy with multimodal diagnostic imaging. The aim of the present study is to evaluate visualization of the endodont with flat-panel detector volume CT (FD-VCT). Materials and methods: 13 human teeth were examined with the prototype of a FD-VCT. After data acquisition and generation of volume data sets in volume rendering technology (VRT), the findings obtained were compared to conventional X-rays and cross-section preparations of the teeth. Results: The anatomical structures of the endodont such as root canals, side canals and communications between different root canals as well as dentricles could be detected precisely with FD-VCT. The length of curved root canals was also determined accurately. The spatial resolution of the system is around 140 μm. Only around 73% of the main root canals detected with FD-VCT and 87% of the roots could be visualized with conventional dental X-rays. None of the side canals, shown with FD-VCT, was detectable on conventional X-rays. In all cases the enamel and dentin of the teeth could be well delineated. No differences in image quality could be discerned between stored and freshly extracted teeth, or between primary and adult teeth. (orig.)

  12. Comparison of the quality of the chest film between digital radiography and conventional high kV radiography

    International Nuclear Information System (INIS)

    Zeng Qingsi; Cen Renli; Chen Ling; He Jianxun; Lin Hanfei

    2003-01-01

    Objective: To evaluate the quality and usefulness of direct digital radiography system in roentgenogram of chest in clinical practice. Methods: 1000 cases of chest roentgenograms with digital radiography and high kV conventional radiography were selected for analysis by 3 senior radiologists. Results: 1. With digital radiography system, the quality of chest film was assessed as grade A in 50.6%, grade B in 38.5%, grade C in 10.9%, and no waste film. 2. With conventional high kV radiography, the quality of chest film was assessed as grade A in 41.1%, grade B in 44.1%, grade C in 13.3%, and waste film in 1.5%. The direct digital radiography was statistically superior to the conventional high kV radiography. 3. The fine structure of the lungs could be revealed in 100.0% of chest roentgenogram with direct digital radiograph system, which was significantly higher than that acquired with the conventional high KV radiography (78.6%, P < 0.001). Conclusion: Direct digital radiography could provide the chest film with better quality than that with the conventional high kV radiography. The direct digital radiography system is easy to operate, fast in capturing imaging and could provide post-processing techniques, which will facilitate the accurate diagnosis of chest radiography

  13. Chest radiography and abdominal ultrasound in general practice

    NARCIS (Netherlands)

    Speets, Anouk Mariëlle

    2006-01-01

    Chest radiography (CXR) and abdominal ultrasound (US) are two widely used diagnostic imaging techniques in Western societies. General practitioners (GPs) in The Netherlands annually request approximately 500,000 CXRs and 200,000 abdominal US, and therefore clearly place a burden on health care.

  14. Utility of routine postoperative chest radiography in pediatric tracheostomy.

    Science.gov (United States)

    Genther, Dane J; Thorne, Marc C

    2010-12-01

    Routine chest radiography following pediatric tracheostomy is commonly performed in order to evaluate for air-tracking complications. Routine chest radiography affords disadvantages of radiation exposure and cost. The primary objective of this study was to determine the utility of routine postoperative chest radiography following tracheostomy in pediatric patients. Secondary objectives were to compare the rates of postoperative complications by various patient and surgeon characteristics. All infants and children 18 years of age or less (n=421) who underwent tracheostomy at a single tertiary-care medical center from January 2000 to April 2009 were included in the study. A combination of data obtained from billing and administrative systems and review of electronic medical records were recorded and compiled in a database for statistical analysis. Three air-tracking complications (2 pneumothoraces and 1 pneumomediastinum) were identified in our population of 421 pediatric patients, for an incidence of 0.71% (95% CI: 0.1-2.0%). No significant relationships were found between the incidence of air-tracking complication and surgical specialty, patient age, or type of procedure (elective, urgent/emergent). Our study identified a low rate of pneumothorax and pneumomediastinum following pediatric tracheostomy. In all three cases, the pneumothorax was suspected clinically. This finding suggests that postoperative chest radiography should be reserved for cases where there is suspicion of a complication on the basis of intraoperative findings or clinical parameters. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  15. The place of clinical features and standard chest radiography in ...

    African Journals Online (AJOL)

    One hundred and five primary mediastinal masses were seen between 1975 and 1998, at the Cardiothoracic surgical Unit of the University College Hospital Ibadan. These were studied to establish the importance of clinical features and plain chest radiography in preoperative evaluation of these masses. The sources of ...

  16. A study on the scattered dose in portable chest radiography

    International Nuclear Information System (INIS)

    Ahn, Bong Seon; Lee, Hwan Hyung

    2000-01-01

    The purpose of this study is to survey the present status of portable radiography and the result of free space scattered dose rate when taking a radiography at the general hospital or the university hospital in Taejon city. The results were as follows; The number of cases using portable radiography for three years increased to averages 16.2%, 7.7% per year from January 1st in 1996 to December 31st in 1998. The average of distance of adjacent patients was 219.1 cm at the ward. For portable chest radiography, the free space scattered dose rate was 10.5 mSv/hr at 50 cm distance, 1.8 mSv/hr at 100 cm distance, and 0.2 mSv/hr at 200 cm distance. Therefore, in case of portable chest radiography at the ward, the average of distance of adjacent patients is 219.1 cm, so it dose not have influence on the adjacent patient. But during the portable radiography, a guardian who is close to the patient, doctor, nurse and radiologic technologists has to set up the shield to prevent from the unnecessary radiation or the distance should be as great as possible from the mobile X-ray equipment

  17. Digital radiography of the chest: state of the art

    International Nuclear Information System (INIS)

    Souto, M.; Malagari, K.S.; Tucker, D.; Tahoces, P.G.; Correa, J.; Benakis, V.S.; Roussos, C.; Strigaris, K.A.; Vidal, J.J.; Barnes, G.T.; Fraser, R.G.

    1994-01-01

    Digital image acquisition possesses a number of advantages over conventional systems in radiographic examination of the chest, the most important of which is its greater dynamic range. In addition, once digital images are acquired, they can be processed by computer in ways that cannot be rivalled by conventional analog techniques. Finally, digital images can be stored, retrieved and transmitted to local or remote sites. Here the status of the different digital systems employed in chest radiology and commonly used image processing techniques are reviewed. Also discussed are the current clinical applications of integrating digital chest radiography with a picture archiving and communication system (PACS) along with the difficulties typically encountered. Studies with a variety of digital techniques have been carried out on several fronts. Computed radiography based on photostimulable phosphor (CR) has replaced screen-film imaging in certain applications (i.e. bedside imaging). However, CR has limitations, namely its poor X-ray utilisation efficiency at high X-ray tube voltages and sensitivity to scatter; therefore, it is not ideal for all applications. Recently, a dedicated digital chest unit with excellent X-ray utilisation efficiency at high X-ray tube potentials has been introduced. On the basis of the state-of-the-art capabilities and research during the past decade, recommendations are made regarding the most desirable equipment specifications for dedicated and bedside digital chest radiography. (orig.)

  18. Multiple-beam equalization radiography in chest radiology

    International Nuclear Information System (INIS)

    Axelsson, B.; Forsberg, H.; Hansson, B.; Haverling, M.

    1991-01-01

    The large difference in transmission between the mediastinum and the part of the chest mainly containing lungs causes major problems in chest radiography. A system for advanced multiple beam equalization radiography has been evaluated. Evaluation of image quality has been performed both using standard phantoms and from clinical radiographs. Measurements of radiation dose burden to the patient have been made both in clinical examinations and using an anthropomorphic phantom. The image quality, in areas with low transmission, is substantially increased using the equalization system. In parts of the chest mainly containing lung tissue, conventional systems show an equal or slightly better image quality. The radiation dose burden to the patient is increased by 25 percent using the equation system, as compared to a low-dose air-gap system. In our opinion, the slight increase in radiation dose burden is well motivated by the high quality of the radiographs produced. (orig.)

  19. Variation in X-ray dose quantity using an amorphous selenium based flat-panel detector - a study on the dose reduction rate up to the limit of diagnostical utilization

    International Nuclear Information System (INIS)

    Lehnert, T.; Wohlers, J.; Manegold, K.; Wetter, A.; Jacobi, V.; Mack, M.G.; Vogl, T.J.; Streng, W.

    2006-01-01

    Purpose: To evaluate the diagnostic quality and minimum required dose to obtain acceptable images for diagnostic purposes in the field of musculoskeletal radiology. Materials and methods: A critical comparison of the image quality produced by a novel flat panel detector and the conventional screen/film system using a contrast-detail phantom was performed in phase I. Images from both systems were obtained with the same dose and displayed with similar contrast and density. In phase II images of significant anatomical structures in cadaver extremities obtained using the digital detector system and the standard film/screen system were critically evaluated. After a successive reduction in the X-ray dose for 84 patients in phase III, eight independent radiologists compared the image quality of the screen/film system to that of the novel flat panel detector. Results: Phases I and II revealed a difference in the image quality achieved by the standard screen/film system and the digital detector system to the advantage of the digital detector system. In 77 of 84 patients (91.7%), phase III showed equal image quality after a 50% reduction in the X-ray dose. In 3 cases (3.6%) the image quality and the level of contrast were better. No unified statement could be made for 4 patients (4.7%). Conclusion: Digital imaging of skeletal disorders using the novel flat panel detector makes it possible to reduce the X-ray dose by 50% with equal or even better image quality. (orig.)

  20. Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD).

    Science.gov (United States)

    Russ, M; Shankar, A; Jain, A; Setlur Nagesh, S V; Ionita, C N; Scott, C; Karim, K S; Bednarek, D R; Rudin, S

    2016-02-27

    A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25 μ m pixel pitch, and 1000 μ m thick a-Se layer operating at 10V/ μ m bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

  1. Comparison of Radiation Exposure during Endovascular Treatment of Peripheral Arterial Disease with Flat-Panel Detectors on Mobile C-arm versus Fixed Systems.

    Science.gov (United States)

    Guillou, Marie; Maurel, Blandine; Necib, Hatem; Vent, Pierre-Alexandre; Costargent, Alain; Chaillou, Philippe; Gouëffic, Yann; Kaladji, Adrien

    2018-02-01

    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. Two series of patients undergoing arteriography with intention to treat were included. Each series consisted of 2 nonrandomized groups: an MC-arm group and an FC-arm group. Series 1 evaluated exposure to the patient (MC-arm, n = 113; FC-arm, n = 206) while series 2 evaluated exposure to patients and also health care personnel (MC-arm, n = 24; FC-arm, n = 76). The primary end points for evaluating exposure were air kerma (AK, in mGy) for patients and effective dose for health care personnel (in μSv). After adjustment for the effect of body mass index (analysis of covariance test), AK was found to be lower in the MC-arm group than in the FC-arm group (124.1 ± 142 vs. 173.3 ± 248.7, P = 0.025). There was no difference between the groups with regard to effective dose recorded for senior surgeons or for operating room nurses. However, a higher effective dose was recorded by the MC-arm group external dosimeter for the trainee resident and for nurse anesthetists. In endovascular treatment of lower limb PAD, use of an FC-arm system is associated with more radiation exposure to the patient than an MC-arm system. However, this type of imaging system does not appear to affect exposure to health care personnel. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Digital luminescence radiography using a chest phantom

    International Nuclear Information System (INIS)

    Lyttkens, K.; Kehler, M.; Andersson, B.; Carlsen, S.; Ebbesen, A.; Hochbergs, P.; Stroembaeck, A.

    1993-01-01

    With the introduction of picture and archiving communicating systems an alternative image display for the wards might be a personal computer (PC). The intention with this study was to evaluate the diagnostic image quality of the monitor of a PC compared to that of a workstation. Eighty-five digital radiographs of a chest phantom with simulated tumors in the mediastinum and right lung were saved on optical discs. The examinations were reviewed by 4 radiologists on a monitor at a workstation and at a PC, and receiver operating characteristic (ROC) curves were constructed. No significant difference was found between performance of the PC and the workstation. (orig.)

  3. Efficacy of daily bedside chest radiography as visualized by digital luminescence radiography

    International Nuclear Information System (INIS)

    Kirchner, J.; Stueckle, C.A.; Schilling, E.M.; Peters, J.

    2001-01-01

    To determine the diagnostic impact of daily bedside chest radiography in comparison with digital luminescence technique (DLR; storage phosphor radiography) and conventional film screen radiography, a prospective randomized study was completed in 210 mechanically ventilated patients with a total of 420 analysed radiographs. The patients were allocated to two groups: 150 patients underwent DLR, and 60 patients underwent conventional film screen radiography. Radiological analysis was performed consensually and therapeutic efficacy was assessed by the clinicians. There was no statistical significant difference between the frequency of abnormal findings seen on DLR and conventional film screen radiography. In total, 448 abnormal findings were present in 249 of 300 DLR and 97 of 120 conventional film screen radiographs. The most common findings were signs of overhydration (41 %), pleural effusion (31%), partial collapse of the lung (11%) and pneumothorax (2%). One hundred and twenty-three of 448 (27%) of these abnormal findings were thought to have a considerable impact on patient management. The high rate of abnormal findings with significant impact on patient management suggests that the use of daily bedside chest radiography may be reasonable. Copyright (2001) Blackwell Science Pty Ltd

  4. Computed radiography versus mobile direct radiography for bedside chest radiographs: impact of dose on image quality and reader agreement

    NARCIS (Netherlands)

    de Boo, D. W.; Weber, M.; Deurloo, E. E.; Streekstra, G. J.; Freling, N. J.; Dongelmans, D. A.; Schaefer-Prokop, C. M.

    2011-01-01

    To asses the image quality and potential for dose reduction of mobile direct detector (DR) chest radiography as compared with computed radiography (CR) for intensive care unit (ICU) chest radiographs (CXR). Three groups of age-, weight- and disease-matched ICU patients (n=114 patients; 50 CXR per

  5. Gonad protective effect of radiation protective apron in chest radiography

    International Nuclear Information System (INIS)

    Hashimoto, Masatoshi; Kato, Hideyuki; Fujibuchi, Toshiou; Ochi, Shigehiro; Morita, Fuminori

    2004-01-01

    Depending on the facility, a radiation protective apron (protector) is used to protect the gonad from radiation exposure in chest radiography. To determine the necessity of using a protector during chest radiography, we measured the effect of the protector on the gonad in this study. First, using a human body phantom, we measured the absorbed dose of the female gonad with and without the protector, using a thermoluminescence dosimeter (TLD), and confirmed its protective effect. Using the protector, the absorbed dose was reduced to 28±2% and 39±4% for field sizes of 14 x 17 inch and 14 x 14 inch, respectively. Next, we used Monte Carlo simulation and confirmed, not only the validity of the actual measurement values, but also the fact that the influence of radiation on the absorbed dose of the gonad was mostly from scattered radiation from inside the body for the 14 x 17 inch field size, and also from the X-ray tube for the 14 x 14 inch field size. Although a certain protective effect is achieved by using the protector, the radiation dose to the gonad is only a few μGy even without a protector. Thus, the risk of a genetic effect would be as small as 10 -8 . Given that acceptable risk is below 10 -6 , we conclude the use of a radiation protective apron is not necessary for diagnostic chest radiography. (author)

  6. [Gonad protective effect of radiation protective apron in chest radiography].

    Science.gov (United States)

    Hashimoto, Masatoshi; Kato, Hideyuki; Fujibuchi, Toshiou; Ochi, Shigehiro; Morita, Fuminori

    2004-12-01

    Depending on the facility, a radiation protective apron (protector) is used to protect the gonad from radiation exposure in chest radiography. To determine the necessity of using a protector during chest radiography, we measured the effect of the protector on the gonad in this study. First, using a human body phantom, we measured the absorbed dose of the female gonad with and without the protector, using a thermoluminescence dosimeter (TLD), and confirmed its protective effect. Using the protector, the absorbed dose was reduced to 28+/-2% and 39+/-4% for field sizes of 14 x 17 inch and 14 x 14 inch, respectively. Next, we used Monte Carlo simulation and confirmed, not only the validity of the actual measurement values, but also the fact that the influence of radiation on the absorbed dose of the gonad was mostly from scattered radiation from inside the body for the 14 x 17 inch field size, and also from the X-ray tube for the 14 x 14 inch field size. Although a certain protective effect is achieved by using the protector, the radiation dose to the gonad is only a few microGy even without a protector. Thus, the risk of a genetic effect would be as small as 10(-8). Given that acceptable risk is below 10(-6), we conclude the use of a radiation protective apron is not necessary for diagnostic chest radiography.

  7. Digital luminescence radiography of the chest

    International Nuclear Information System (INIS)

    Kehler, M.

    1991-10-01

    The aim of the present study was to evaluate the efficacy of a digital system in chest radiology compared to the conventional film-screen system. The first studies (1-3) were purely clinical, had two parts, one clinical and one using phantoms, and the 5:th used solely phantoms. Except for the first - pilot - study, the studies were performed as receiver operating characteristic (ROC) analysis. From one exposure, two digital radiographs were obtained, one simulating the film-screen radiograph and one enhanced, using an unsharp mask. The conventional radiograph was compared to this double-image, but in addition to this, even to the simulated normal and enhanced separately (1-3). To evaluate the value of inverted (positive) radiographs, the original digital (negative) radiographs were inverted, and then compared to the originals (4). As digitzation means easy storing and transfer of data and possibility of electronic display, the diagnostic performance of an interactive workstation was assessed (5). In the clinical studies, a variety of chest affections were used: atelectasis, tumor, pneumothorax, fibrosis, mediastinal and bony changes, tuberculosis, incompensations and enlargement of the heart (1), pneumothorax (2), fibrosis (3), and tumor (4). In the phantom studies, test objects simulating tumors (4) and pneumothorax (5) were used. In no study was statistical significant difference seen between the digital and conventional system (p>0.05). Neither in the clinical nor the phantom study did inversion of the radiographs improve diagnostic performance. The workstation performed almost equally well as the radiographs even with a resolution of 1.25 1p/mm compared to the digital radiographs 2.5 and film-screen radiographs 5 1p/mm. (au) (50 refs.)

  8. Volume CT with a flat-panel detector on a mobile, isocentric C-arm: Pre-clinical investigation in guidance of minimally invasive surgery

    International Nuclear Information System (INIS)

    Siewerdsen, J.H.; Moseley, D.J.; Burch, S.; Bisland, S.K.; Bogaards, A.; Wilson, B.C.; Jaffray, D.A.

    2005-01-01

    A mobile isocentric C-arm (Siemens PowerMobil) has been modified in our laboratory to include a large area flat-panel detector (in place of the x-ray image intensifier), providing multi-mode fluoroscopy and cone-beam computed tomography (CT) imaging capability. This platform represents a promising technology for minimally invasive, image-guided surgical procedures where precision in the placement of interventional tools with respect to bony and soft-tissue structures is critical. The image quality and performance in surgical guidance was investigated in pre-clinical evaluation in image-guided spinal surgery. The control, acquisition, and reconstruction system are described. The reproducibility of geometric calibration, essential to achieving high three-dimensional (3D) image quality, is tested over extended time scales (7 months) and across a broad range in C-arm angulation (up to 45 deg.), quantifying the effect of improper calibration on spatial resolution, soft-tissue visibility, and image artifacts. Phantom studies were performed to investigate the precision of 3D localization (viz., fiber optic probes within a vertebral body) and effect of lateral projection truncation (limited field of view) on soft-tissue detectability in image reconstructions. Pre-clinical investigation was undertaken in a specific spinal procedure (photodynamic therapy of spinal metastases) in five animal subjects (pigs). In each procedure, placement of fiber optic catheters in two vertebrae (L1 and L2) was guided by fluoroscopy and cone-beam CT. Experience across five procedures is reported, focusing on 3D image quality, the effects of respiratory motion, limited field of view, reconstruction filter, and imaging dose. Overall, the intraoperative cone-beam CT images were sufficient for guidance of needles and catheters with respect to bony anatomy and improved surgical performance and confidence through 3D visualization and verification of transpedicular trajectories and tool placement

  9. Performance evaluation of a direct-conversion flat-panel detector system in imaging and quality assurance for a high-dose-rate 192Ir source

    Science.gov (United States)

    Miyahara, Yoshinori; Hara, Yuki; Nakashima, Hiroto; Nishimura, Tomonori; Itakura, Kanae; Inomata, Taisuke; Kitagaki, Hajime

    2018-03-01

    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 was unknown why iridium is visible when using a d-FPD. The purpose of this study was to clarify the 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, and linearity of d-FPD to high-energy gamma rays. The acquired data included: x-rays, [X]; gamma rays, [γ] dual rays (X  +  γ), [D], and subtracted data for depicting the source ([D]  -  [γ]). In the quality assurance (QA) test for the positional accuracy of a source core, the coordinates of each dwelling point were compared between the planned and actual source core positions using a CT/MR-compatible ovoid applicator and a Fletcher-Williamson applicator. The profile curves of [X] and ([D]  -  [γ]) matched well on MTF and NPS. The contrast resolutions of [D] and [X] were equivalent. A strongly positive linear correlation was found between the output data of [γ] and source strength (r 2  >  0.99). With regard to the accuracy of the source core position, the largest coordinate difference (3D distance) was noted at the maximum curvature of the CT/MR-compatible ovoid and Fletcher-Williamson applicators, showing 1.74  ±  0.02 mm and 1.01  ±  0.01 mm, respectively. A d-FPD system provides high-quality images of a source, even when high-energy gamma rays are emitted to the detector, and positional accuracy tests with clinical applicators are useful in identifying source positions (source movements) within the applicator for QA.

  10. Pulmonary disease in cystic fibrosis: assessment with chest CT at chest radiography dose levels.

    Science.gov (United States)

    Ernst, Caroline W; Basten, Ines A; Ilsen, Bart; Buls, Nico; Van Gompel, Gert; De Wachter, Elke; Nieboer, Koenraad H; Verhelle, Filip; Malfroot, Anne; Coomans, Danny; De Maeseneer, Michel; de Mey, Johan

    2014-11-01

    To investigate a computed tomographic (CT) protocol with iterative reconstruction at conventional radiography dose levels for the assessment of structural lung abnormalities in patients with cystic fibrosis ( CF cystic fibrosis ). In this institutional review board-approved study, 38 patients with CF cystic fibrosis (age range, 6-58 years; 21 patients 18 years) underwent investigative CT (at minimal exposure settings combined with iterative reconstruction) as a replacement of yearly follow-up posteroanterior chest radiography. Verbal informed consent was obtained from all patients or their parents. CT images were randomized and rated independently by two radiologists with use of the Bhalla scoring system. In addition, mosaic perfusion was evaluated. As reference, the previous available conventional chest CT scan was used. Differences in Bhalla scores were assessed with the χ(2) test and intraclass correlation coefficients ( ICC intraclass correlation coefficient s). Radiation doses for CT and radiography were assessed for adults (>18 years) and children (chest CT protocol can replace the two yearly follow-up chest radiographic examinations without major dose penalty and with similar diagnostic quality compared with conventional CT.

  11. Clinical aspects of plain film radiography of the chest

    International Nuclear Information System (INIS)

    Ravin, C.E.

    1988-01-01

    In spite of the introduction of a number of intriguing new imaging modalities including Computed Tomography and Magnetic Resonance Imaging, the plain film of the chest remains the mainstay of thoracic imaging. It is estimated that more than fifty million chest radiographs are performed each year in the United States. In the attempt to compare newer imaging modalities with the standard plain film of the chest, investigators have been forced to adopt specific structures and or disease processes to be analyzed. To some extent identification of normally appearing structures in the mediastinum and lung parenchyma serves as a clue as to the ability of a newer technology to compete with or be compared with the plain film. However, as most authors would acknowledge, the ability to portray normal underlying anatomy is only the first step in analysis in intrathoracic disease. Experimental design becomes somewhat more complicated when one wishes to move beyond normal anatomy to analysis of disease processes. The challenge of digital radiography in whatever form it may take will be to equal or exceed the standard established by conventional plain film radiography and deliver such service at reasonable cost in a manner which allows for appropriate patient throughput

  12. Patient dose measurement and dose reduction in chest radiography

    Directory of Open Access Journals (Sweden)

    Milatović Aleksandra A.

    2014-01-01

    Full Text Available Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area product of patient doses. In the second stage, the possibilities for dose reduction were investigated. Mean kerma area product values were 0.8 ± 0.5 Gycm2 for the posterior-anterior projection and 1.6 ± 0.9 Gycm2 for the lateral projection. The max/min ratio for the entrance surface air kerma was found to be 53 for the posterior-anterior projection and 88 for the lateral projection. Comparing the results obtained in Montenegro with results from other countries, we concluded that patient doses in our medical centres are significantly higher. Changes in exposure parameters and increased filtration contributed to a dose reduction of up to 36% for posterior-anterior chest examinations. The variability of the estimated dose values points to a significant space for dose reduction throughout the process of radiological practice optimisation.

  13. Dose and perceived image quality in chest radiography

    International Nuclear Information System (INIS)

    Veldkamp, Wouter J.H.; Kroft, Lucia J.M.; Geleijns, Jacob

    2009-01-01

    Chest radiography is the most commonly performed diagnostic X-ray examination. The radiation dose to the patient for this examination is relatively low but because of its frequent use, the contribution to the collective dose is considerable. Consequently, optimization of dose and image quality offers a challenging area of research. In this article studies on dose reduction, different detector technologies, optimization of image acquisition and new technical developments in image acquisition and post processing will be reviewed. Studies indicate that dose reduction in PA chest images to at least 50% of commonly applied dose levels does not affect diagnosis in the lung fields; however, dose reduction in the mediastinum, upper abdomen and retrocardiac areas appears to directly deteriorate diagnosis. In addition to patient dose, also the design of the various digital detectors seems to have an effect on image quality. With respect to image acquisition, studies showed that using a lower tube voltage improves visibility of anatomical structures and lesions in digital chest radiographs but also increases the disturbing appearance of ribs. New techniques that are currently being evaluated are dual energy, tomosynthesis, temporal subtraction and rib suppression. These technologies may improve diagnostic chest X-ray further. They may for example reduce the negative influence of over projection of ribs, referred to as anatomic noise. In chest X-ray this type of noise may be the dominating factor in the detection of nodules. In conclusion, optimization and new developments will enlarge the value of chest X-ray as a mainstay in the diagnosis of chest diseases.

  14. Chest Tomosynthesis: Technical Principles and Clinical Update

    Science.gov (United States)

    Dobbins, James T.; McAdams, H. Page

    2009-01-01

    Digital tomosynthesis is a radiographic technique that can produce an arbitrary number of section images of a patient from a single pass of the x-ray tube. It utilizes a conventional x-ray tube, a flat-panel detector, a computer-controlled tube mover, and special reconstruction algorithms to produce section images. While it does not have the depth resolution of computed tomography (CT), tomosynthesis provides some of the tomographic benefits of CT but at lower cost and radiation dose than CT. Compared to conventional chest radiography, chest tomosynthesis results in improved visibility of normal structures such as vessels, airway and spine. By reducing visual clutter from overlying normal anatomy, it also enhances detection of small lung nodules. This review article outlines the components of a tomosynthesis system, discusses results regarding improved lung nodule detection from the recent literature, and presents examples of nodule detection from a clinical trial in human subjects. Possible implementation strategies for use in clinical chest imaging are discussed. PMID:19616909

  15. Quality of outpatient paediatric chest radiography - a pilot study

    International Nuclear Information System (INIS)

    Engelmann, D.; Duetting, T.; Wunsch, R.; Troeger, J.

    2001-01-01

    A quality control of outpatient paediatric chest X-rays was conducted in a sample of patients of one paediatric practice. During a period of eight months the technical image quality was analysed considering both diagnostic aspects and radiation protection. The quality of the 139 examined chest X-rays was inadequate concerning the collimation and focussing of the X-rays and the positioning of the patients. Exposure was estimated as average, sharpness was rated as good. In total 14% of the X-rays were not suitable for medical diagnosis. Image quality of the X-rays of infants (children younger than 6 years) was significantly lower compared to the total sample. Radiation protection standards were not fulfilled. As a conclusion from our results, improvements in outpatient paediatric radiography are urgently necessary. Quality control committees should pay particular attention in radiographs of infants. (orig.) [de

  16. ACR Appropriateness Criteria® Routine Chest Radiography.

    Science.gov (United States)

    McComb, Barbara L; Chung, Jonathan H; Crabtree, Traves D; Heitkamp, Darel E; Iannettoni, Mark D; Jokerst, Clinton; Saleh, Anthony G; Shah, Rakesh D; Steiner, Robert M; Mohammed, Tan-Lucien H; Ravenel, James G

    2016-03-01

    Chest radiographs are sometimes taken before surgeries and interventional procedures on hospital admissions and outpatients. This manuscript summarizes the American College of Radiology review of the literature and recommendations on routinely performed chest radiographies in these settings. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

  17. Developments in dual-energy, single-exposure chest radiography

    International Nuclear Information System (INIS)

    Ho Jungtsuoe.

    1990-01-01

    Conventional chest radiography (CCR), the most commonly performed technique for the diagnosis of lung cancer, does not detect a high percentage of these tumors. One reason for errors is the overlap of tumor image with bone image in a chest radiograph. Dual-energy (DE) radiography has been suggested as the most effective method to eliminate bone contrast for better lung tumor visualization. DE radiography also provides a bone image from which benign nodules can be identified by the presence of nodule calcification. The purpose of this study is to evaluate the performance of a film-screen based DE, single exposure technique in lung nodule detection and to improve its performance by both hardware (HD) and software developments (SD) to increase the accuracy of lung cancer diagnosis. Previous implementation of the technique resulted in small residual tissue contrast and incomplete tissue subtraction due to screen selection and x-ray beam hardening, respectively. HD, including uses of a new screen pair (Y 2 O 2 S/CaWO 4 ) and a K-edge filter (europium), were studied to improve residual tissue contrast by increasing the energy separation. Successful SD included a three-dimensional interpolation algorithm and noise suppression methods to achieve complete tissue subtraction and noise reduction, respectively. The results show that the new screen pair performed better than LaOBr/CaWo 4 ; the use of K-edge filter produced more residual tissue contrast than that obtained without it. Even though the dual exposure technique performed better than the single exposure technique in a simulated lung nodule detection study, the difference between the two techniques was statistically insignificant and they both performed better than CCR. Based on these encouraging results, the author concludes that the film-screen based DE, single exposure technique, with the HD and SD holds promise for further clinical study

  18. Temporal subtraction in chest radiography: Automated assessment of registration accuracy

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Doshi, Devang J.; Engelmann, Roger; Croteau, Charles L.; MacMahon, Heber

    2006-01-01

    Radiologists routinely compare multiple chest radiographs acquired from the same patient over time to more completely understand changes in anatomy and pathology. While such comparisons are achieved conventionally through a side-by-side display of images, image registration techniques have been developed to combine information from two separate radiographic images through construction of a 'temporal subtraction image'. Although temporal subtraction images provide a powerful mechanism for the enhanced visualization of subtle change, errors in the clinical evaluation of these images may arise from misregistration artifacts that can mimic or obscure pathologic change. We have developed a computerized method for the automated assessment of registration accuracy as demonstrated in temporal subtraction images created from radiographic chest image pairs. The registration accuracy of 150 temporal subtraction images constructed from the computed radiography images of 72 patients was rated manually using a five-point scale ranging from '5-excellent' to '1-poor'; ratings of 3, 4, or 5 reflected clinically acceptable subtraction images, and ratings of 1 or 2 reflected clinically unacceptable images. Gray-level histogram-based features and texture measures are computed at multiple spatial scales within a 'lung mask' region that encompasses both lungs in the temporal subtraction images. A subset of these features is merged through a linear discriminant classifier. With a leave-one-out-by-patient training/testing paradigm, the automated method attained an A z value of 0.92 in distinguishing between temporal subtraction images that demonstrated clinically acceptable and clinically unacceptable registration accuracy. A second linear discriminant classifier yielded an A z value of 0.82 based on a feature subset selected from an independent database of digitized film images. These methods are expected to advance the clinical utility of temporal subtraction images for chest

  19. A method to optimize the processing algorithm of a computed radiography system for chest radiography.

    Science.gov (United States)

    Moore, C S; Liney, G P; Beavis, A W; Saunderson, J R

    2007-09-01

    A test methodology using an anthropomorphic-equivalent chest phantom is described for the optimization of the Agfa computed radiography "MUSICA" processing algorithm for chest radiography. The contrast-to-noise ratio (CNR) in the lung, heart and diaphragm regions of the phantom, and the "system modulation transfer function" (sMTF) in the lung region, were measured using test tools embedded in the phantom. Using these parameters the MUSICA processing algorithm was optimized with respect to low-contrast detectability and spatial resolution. Two optimum "MUSICA parameter sets" were derived respectively for maximizing the CNR and sMTF in each region of the phantom. Further work is required to find the relative importance of low-contrast detectability and spatial resolution in chest images, from which the definitive optimum MUSICA parameter set can then be derived. Prior to this further work, a compromised optimum MUSICA parameter set was applied to a range of clinical images. A group of experienced image evaluators scored these images alongside images produced from the same radiographs using the MUSICA parameter set in clinical use at the time. The compromised optimum MUSICA parameter set was shown to produce measurably better images.

  20. Evaluation of chest tomosynthesis for the detection of pulmonary nodules: effect of clinical experience and comparison with chest radiography

    Science.gov (United States)

    Zachrisson, Sara; Vikgren, Jenny; Svalkvist, Angelica; Johnsson, Åse A.; Boijsen, Marianne; Flinck, Agneta; Månsson, Lars Gunnar; Kheddache, Susanne; Båth, Magnus

    2009-02-01

    Chest tomosynthesis refers to the technique of collecting low-dose projections of the chest at different angles and using these projections to reconstruct section images of the chest. In this study, a comparison of chest tomosynthesis and chest radiography in the detection of pulmonary nodules was performed and the effect of clinical experience of chest tomosynthesis was evaluated. Three senior thoracic radiologists, with more than ten years of experience of chest radiology and 6 months of clinical experience of chest tomosynthesis, acted as observers in a jackknife free-response receiver operating characteristics (JAFROC-1) study, performed on 42 patients with and 47 patients without pulmonary nodules examined with both chest tomosynthesis and chest radiography. MDCT was used as reference and the total number of nodules found using MDCT was 131. To investigate the effect of additional clinical experience of chest tomosynthesis, a second reading session of the tomosynthesis images was performed one year after the initial one. The JAFROC-1 figure of merit (FOM) was used as the principal measure of detectability. In comparison with chest radiography, chest tomosynthesis performed significantly better with regard to detectability. The observer-averaged JAFROC-1 FOM was 0.61 for tomosynthesis and 0.40 for radiography, giving a statistically significant difference between the techniques of 0.21 (p<0.0001). The observer-averaged JAFROC-1 FOM of the second reading of the tomosynthesis cases was not significantly higher than that of the first reading, indicating no improvement in detectability due to additional clinical experience of tomosynthesis.

  1. Nodule detection in digital chest radiography: Summary of the radius chest trial

    International Nuclear Information System (INIS)

    Haakansson, M.; Baath, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattson, S.; Maansson, L. G.

    2005-01-01

    As a part of the Europe-wide research project 'Unification of physical and clinical requirements for medical X-ray imaging' - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial aimed at thoroughly examining various aspects of nodule detection in digital chest radiography, such as the effects of nodule location, system noise, anatomical noise, and anatomical background. The main findings of the RADIUS chest trial concerning the detection of a lung nodule with a size in the order of 10 mm can be summarised as: (1) the detectability of the nodule is largely dependent on its location in the chest, (2) the system noise has a minor impact on the detectability at the dose levels used today, (3) the disturbance of the anatomical noise is larger than that of the system noise but smaller than that of the anatomical background and (4) the anatomical background acts as noise to a large extent and is the major image component affecting the detectability of the nodule. (authors)

  2. Studies on image quality and dose exposure in chest radiography in children

    International Nuclear Information System (INIS)

    Schumacher, R.

    1985-01-01

    Chest radiography accounts for almost 50% of all radiographies in radiological departments for children, thus clearly dominating X-ray performances. The indications for examination in children are frequent infections of the upper airways, congenital cardiac defects, and controls in oncological patients. By contrast, indications for radioscopy of the chest organs which figure greatly in adult age and are often required concurrently with every chest radiography, are rather rare in the patient group of a paediatric X-ray department with their rate of c. 0.5% related to chest radiography. Chest radiographs and phantom radiographs were produced using different techniques and were compared by means of subjective and objective image quality parameters. Concurrently, thermoluminescence dosimetry was used to perform dose measurements of the small gonadal dose occurring in patients in chest radiographies. The study aimed at finding a chest radiography technique appropriate for use in paediatric radiology while considering both image quality parameters and the radiation dose required for producing pictures. (orig./DG) [de

  3. Digital radiography in NDT applications

    International Nuclear Information System (INIS)

    Deprins, E.

    2004-01-01

    A lot of film radiography could be replaced by today's technologies in the field of digital radiography. Only few of these applications have indeed replaced film. The choice to go digital depends on cost, quality requirement, workflow and throughput. Digital images offer a lot of advantages in terms of image manipulation and workflow. But despite the many advantages, a lot of considerations are needed before someone can decide to convert his organization from conventional to digital radiography. This paper gives an overview of all different modalities that can be used in digital radiography with today's technologies, together with the experiences of the pioneers of digital radiography. Film Scanning, Computed Radiography and Digital Radiography by using of different kinds of flat panel detectors all have their specific application fields and customers. What is the status of the technology today, which advantages brings digital radiography, and which are the limitations radiographers have to consider when replacing film by digital systems. (author)

  4. Evaluation of entrance surface air kerma in pediatric chest radiography

    International Nuclear Information System (INIS)

    Porto, L.; Lunelli, N.; Paschuk, S.; Oliveira, A.; Ferreira, J.L.; Schelin, H.; Miguel, C.; Denyak, V.; Kmiecik, C.; Tilly, J.; Khoury, H.

    2014-01-01

    The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior–posterior (AP) and posterior–anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0–1 y, 1–5 y, 5–10 y, and 10–15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels. - Highlights: • The entrance surface air kerma of chest X-ray examinations in pediatric patients was estimated. • The data were analyzed for patients aged up to 15 y, stratified by age. • The doses of LAT examinations were 40% higher than of AP/PA because of kV used. • An increase in kV with a decrease in mAs leads to significant dose reduction

  5. The “dirty chest”—correlations between chest radiography, multislice CT and tobacco burden

    Science.gov (United States)

    Kirchner, J; Goltz, J P; Lorenz, F; Obermann, A; Kirchner, E M; Kickuth, R

    2012-01-01

    Objectives Cigarette smoking-induced airway disease commonly results in an overall increase of non-specific lung markings on chest radiography. This has been described as “dirty chest”. As the morphological substrate of this condition is similar to the anthracosilicosis of coal workers, we hypothesised that it is possible to quantify the radiological changes using the International Labour Organization (ILO) classification of pneumoconiosis. The aims of this study were to evaluate whether there is a correlation between the extent of cigarette smoking and increased lung markings on chest radiography and to correlate the chest radiographic scores with findings on CT studies. Methods In a prospective analysis a cohort of 85 smokers was examined. The cigarette consumption was evaluated in pack years (defined as 20 cigarettes per day over 1 year). Film reading was performed by two board-certified radiologists. Chest radiographs were evaluated for the presence of thickening of bronchial walls, the presence of linear or nodular opacities, and emphysema. To correlate the smoking habits with the increase of overall lung markings in chest radiography, the ILO profusion score was converted to numbers ranging from zero to nine. Chest radiographs were rated according to the complete set of standard films of the revised ILO classification. Results 63/85 (74%) of the smokers showed an increase in overall lung markings on chest radiography; 32 (37%) had an ILO profusion score of chest radiography and the cigarette consumption quantified as pack years (r=0.68). The majority of the heavy smokers (>40 pack years) showed emphysema; there was no significant difference between the prevalence of emphysema as diagnosed by CT (62%) or chest radiography (71%) (pchest radiography. PMID:21937617

  6. Evaluation of entrance surface air kerma in pediatric chest radiography

    Science.gov (United States)

    Porto, L.; Lunelli, N.; Paschuk, S.; Oliveira, A.; Ferreira, J. L.; Schelin, H.; Miguel, C.; Denyak, V.; Kmiecik, C.; Tilly, J.; Khoury, H.

    2014-11-01

    The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior-posterior (AP) and posterior-anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0-1 y, 1-5 y, 5-10 y, and 10-15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels.

  7. Optimization of selective exposure radiography of the chest

    International Nuclear Information System (INIS)

    Naimuddin, S.

    1986-01-01

    A major technical limitation in conventional chest radiography is the mismatch of the x-ray transmission dynamic range with the useful exposure range of a radiographic film when a patient is presented with a uniform incident exposure field. The goal of this project is to develop a faster and more reliable selective exposure system to fabricate and position a compensating filter (or digital beam attenuator, DBA) for clinical use. The essential components of this system include a dose efficient test-image detector, a special purpose field grabber (image memory), a custom made fast printer, a transport channel, and a computer. The fabrication process begins with acquisition of a 64 x 64 format low-dose patient image which undergoes corrections for detector nonuniformity and scatter. The corrected data after log transformation are used to calculate thickness of filter material needed to compensate for the image dynamic range. Using this thickness information the computer controls the printer which fabricates as attenuator by overprinting multiple layers of cerium oxide on a 35 mm film substrate. Although the images are acquired in a 64 x 64 format, the attenuator is constructed in a dithered 16 x 16 format using a special algorithm. After fabrication, the attenuator is automatically conveyed through the transport channel and is positioned in the x-ray beam between the collimator and x-ray tube before the final compensated radiograph is taken

  8. Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system.

    Science.gov (United States)

    Moore, C S; Wood, T J; Beavis, A W; Saunderson, J R

    2013-07-01

    The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson's correlation coefficient. Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, pchest CR images acquired without an antiscatter grid. A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography.

  9. Nodule detection in digital chest radiography: Introduction to the radius chest trial

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattsson, S.; Maansson, L. G.

    2005-01-01

    Most digital radiographic systems of today have wide latitude and are hence able to provide images with a small constraint on dose level. This opens up for an unprejudiced dose optimisation. However, in order to succeed in the optimisation task, good knowledge of the imaging and detection processes is needed. As a part of the European-wide research project 'unification of physical and clinical requirements for medical X-ray imaging - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial was focused on the detection of lung nodules in digital chest radiography with the aims of determining to what extent (1) the detection of a nodule is dependent on its location, (2) the system noise disturbs the detection of lung nodules, (3) the anatomical noise disturbs the detection of lung nodules and (4) the image background and anatomical background act as pure noise for the detection of lung nodules. The purpose of the present paper is to give an introduction to the trial and describe the framework and set-up of the investigation. (authors)

  10. The phrenic nerve with accompanying vessels: a silent cause of cardiovascular border obliteration on chest radiography.

    Science.gov (United States)

    Farhana, Shiri; Ashizawa, Kazuto; Hayashi, Hideyuki; Ogihara, Yukihiro; Aso, Nobuya; Hayashi, Kuniaki; Uetani, Masataka

    2015-12-01

    Our aim was to clarify the frequency of cardiovascular border obliteration on frontal chest radiography and to prove that the phrenic nerve with accompanying vessels can be considered as a cause of obliteration of cardiovascular border on an otherwise normal chest radiography. Two radiologists reviewed chest radiographs and computed tomography (CT) images of 100 individuals. CT confirmed the absence of intrapulmonary or extrapulmonary abnormalities in all of them. We examined the frequency of cardiovascular border obliteration on frontal chest radiography and summarized the causes of obliteration as pericardial fat pad, phrenic nerve, intrafissure fat, pulmonary vessels, and others, comparing them with CT in each case. Cardiovascular border was obliterated on frontal chest radiography in 46 cases on the right and in 61 on the left. The phrenic nerve with accompanying vessels was found to be a cause of obliteration in 34 of 46 cases (74%) on the right and 29 of 61 (48%) cases on the left. The phrenic nerve was the most frequent cause of cardiovascular border obliteration on both sides. The phrenic nerve with accompanying vessels, forming a prominent fold of parietal pleura, can be attributed as a cause of cardiovascular border obliteration on frontal chest radiography.

  11. Chest radiography practice in critically ill patients: a postal survey in the Netherlands

    International Nuclear Information System (INIS)

    Graat, Marleen E; Hendrikse, Karin A; Spronk, Peter E; Korevaar, Johanna C; Stoker, Jaap; Schultz, Marcus J

    2006-01-01

    To ascertain current chest radiography practice in intensive care units (ICUs) in the Netherlands. Postal survey: a questionnaire was sent to all ICUs with > 5 beds suitable for mechanical ventilation; pediatric ICUs were excluded. When an ICU performed daily-routine chest radiographs in any group of patients it was considered to be a 'daily-routine chest radiography' ICU. From the number of ICUs responding, 63% practice a daily-routine strategy, in which chest radiographs are obtained on a daily basis without any specific reason. A daily-routine chest radiography strategy is practiced less frequently in university-affiliated ICUs (50%) as compared to other ICUs (68%), as well as in larger ICUs (> 20 beds, 50%) as compared to smaller ICUs (< 20 beds, 65%) (P > 0.05). Remarkably, physicians that practice a daily-routine strategy consider daily-routine radiographs helpful in guiding daily practice in less than 30% of all performed radiographs. Chest radiographs are considered essential for verification of the position of invasive devices (81%) and for diagnosing pneumothorax, pneumonia or acute respiratory distress syndrome (82%, 74% and 69%, respectively). On demand chest radiographs are obtained after introduction of thoracic drains, central venous lines and endotracheal tubes in 98%, 84% and 75% of responding ICUs, respectively. Chest films are also obtained in case of ventilatory deterioration (49% of responding ICUs), and after cardiopulmonary resuscitation (59%), tracheotomy (58%) and mini-tracheotomy (23%). There is notable lack of consensus on chest radiography practice in the Netherlands. This survey suggests that a large number of intensivists may doubt the value of daily-routine chest radiography, but still practice a daily-routine strategy

  12. Multi-Institutional Evaluation of Digital Tomosynthesis, Dual-Energy Radiography, and Conventional Chest Radiography for the Detection and Management of Pulmonary Nodules.

    Science.gov (United States)

    Dobbins, James T; McAdams, H Page; Sabol, John M; Chakraborty, Dev P; Kazerooni, Ella A; Reddy, Gautham P; Vikgren, Jenny; Båth, Magnus

    2017-01-01

    Purpose To conduct a multi-institutional, multireader study to compare the performance of digital tomosynthesis, dual-energy (DE) imaging, and conventional chest radiography for pulmonary nodule detection and management. Materials and Methods In this binational, institutional review board-approved, HIPAA-compliant prospective study, 158 subjects (43 subjects with normal findings) were enrolled at four institutions. Informed consent was obtained prior to enrollment. Subjects underwent chest computed tomography (CT) and imaging with conventional chest radiography (posteroanterior and lateral), DE imaging, and tomosynthesis with a flat-panel imaging device. Three experienced thoracic radiologists identified true locations of nodules (n = 516, 3-20-mm diameters) with CT and recommended case management by using Fleischner Society guidelines. Five other radiologists marked nodules and indicated case management by using images from conventional chest radiography, conventional chest radiography plus DE imaging, tomosynthesis, and tomosynthesis plus DE imaging. Sensitivity, specificity, and overall accuracy were measured by using the free-response receiver operating characteristic method and the receiver operating characteristic method for nodule detection and case management, respectively. Results were further analyzed according to nodule diameter categories (3-4 mm, >4 mm to 6 mm, >6 mm to 8 mm, and >8 mm to 20 mm). Results Maximum lesion localization fraction was higher for tomosynthesis than for conventional chest radiography in all nodule size categories (3.55-fold for all nodules, P chest radiography for all nodules (1.49-fold, P chest radiography, as given by the area under the receiver operating characteristic curve (1.23-fold, P chest radiography or tomosynthesis. Conclusion Tomosynthesis outperformed conventional chest radiography for lung nodule detection and determination of case management; DE imaging did not show significant differences over conventional chest

  13. Effects of optimization and image processing in digital chest radiography

    International Nuclear Information System (INIS)

    Kheddache, S.; Maansson, L.G.; Angelhed, J.E.; Denbratt, L.; Gottfridsson, B.; Schlossman, D.

    1991-01-01

    A digital system for chest radiography based on a large image intensifier was compared to a conventional film-screen system. The digital system was optimized with regard to spatial and contrast resolution and dose. The images were digitally processed for contrast and edge enhancement. A simulated pneumothorax and two and two simulated nodules were positioned over the lungs and the mediastinum of an anthro-pomorphic phantom. Observer performance was evaluated with Receiver Operating Characteristic (ROC) analysis. Five observers assessed the processed digital images and the conventional full-size radiographs. The time spent viewing the full-size radiographs and the digital images was recorded. For the simulated pneumothorax, the results showed perfect performance for the full-size radiographs and detectability was high also for the processed digital images. No significant differences in the detectability of the simulated nodules was seen between the two imaging systems. The results for the digital images showed a significantly improved detectability for the nodules in the mediastinum as compared to a previous ROC study where no optimization and image processing was available. No significant difference in detectability was seen between the former and the present ROC study for small nodules in the lung. No difference was seen in the time spent assessing the conventional full-size radiographs and the digital images. The study indicates that processed digital images produced by a large image intensifier are equal in image quality to conventional full-size radiographs for low-contrast objects such as nodules. (author). 38 refs.; 4 figs.; 1 tab

  14. Indirect flat-panel detector with avalanche gain: Fundamental feasibility investigation for SHARP-AMFPI (scintillator HARP active matrix flat panel imager)

    International Nuclear Information System (INIS)

    Zhao Wei; Li Dan; Reznik, Alla; Lui, B.J.M.; Hunt, D.C.; Rowlands, J.A.; Ohkawa, Yuji; Tanioka, Kenkichi

    2005-01-01

    An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic image is read out using an active matrix array of thin film transistors (TFT). We call the proposed detector SHARP-AMFPI (scintillator HARP active matrix flat panel imager). The advantage of the SHARP-AMFPI is its programmable gain, which can be turned on during low dose fluoroscopy to overcome electronic noise, and turned off during high dose radiography to avoid pixel saturation. The purpose of this paper is to investigate the important design considerations for SHARP-AMFPI such as avalanche gain, which depends on both the thickness d Se and the applied electric field E Se of the HARP layer. To determine the optimal design parameter and operational conditions for HARP, we measured the E Se dependence of both avalanche gain and optical quantum efficiency of an 8 μm HARP layer. The results were used in a physical model of HARP as well as a linear cascaded model of the FPI to determine the following x-ray imaging properties in both the avalanche and nonavalanche modes as a function of E Se : (1) total gain (which is the product of avalanche gain and optical quantum efficiency); (2) linearity; (3) dynamic range; (4) gain nonuniformity resulting from thickness nonuniformity; and (5) effects of direct x-ray interaction in HARP. Our results showed that a HARP layer thickness of 8 μm can provide adequate avalanche gain and sufficient dynamic range for x-ray imaging applications to permit quantum limited operation over the range of exposures needed for radiography and fluoroscopy

  15. Dichotomy between theory and practice in chest radiography and its impact on students.

    Science.gov (United States)

    Botwe, Benard O; Arthur, Lawrence; Tenkorang, Michael K K; Anim-Sampong, Samuel

    2017-06-01

    It is important that theory is synchronous with clinical practices that students engage in. Lack of congruence between theory and practice presents serious problems to students. This study was therefore conducted to determine if there was a theory-practice gap in chest radiography during clinical rotations, and any associated causes and effects on radiography students. A descriptive survey design was used to conduct this study from 2 February to 27 July 2014. A semi-structured questionnaire consisting of open- and close-ended questions was used to purposively collect data from 26 radiography students in Ghana who had completed theory lessons in chest radiography and had either completed or were undertaking clinical rotations in chest radiography. Twenty-five (96%) respondents indicated the presence of theory-practice gap in chest radiography during clinical rotations, where differences between theory and clinical practice were observed. Lack of working materials 16 (62%), heavy workload 14 (54%), equipment breakdowns 14 (54%) and supervisory factors 11 (43%) were identified as the causes. Many students (81%) experienced diverse adverse effects such as confusion 10 (38%), poor performance during clinical examinations 6 (23%) and entire loss of interest in the professional training 1 (4%) of this dichotomy. Dichotomy between theory and practice found in chest radiography has diverse adverse effects on students. Regular feedback on the quality of clinical practice received by students should be encouraged to determine the existence of any gaps between theory and practice in order to promote effective clinical rotation programmes in radiography. © 2016 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.

  16. Effect of Localizer Radiography Projection on Organ Dose at Chest CT with Automatic Tube Current Modulation.

    Science.gov (United States)

    Saltybaeva, Natalia; Krauss, Andreas; Alkadhi, Hatem

    2017-03-01

    Purpose To calculate the effect of localizer radiography projections to the total radiation dose, including both the dose from localizer radiography and that from subsequent chest computed tomography (CT) with tube current modulation (TCM). Materials and Methods An anthropomorphic phantom was scanned with 192-section CT without and with differently sized breast attachments. Chest CT with TCM was performed after one localizer radiographic examination with anteroposterior (AP) or posteroanterior (PA) projections. Dose distributions were obtained by means of Monte Carlo simulations based on acquired CT data. For Monte Carlo simulations of localizer radiography, the tube position was fixed at 0° and 180°; for chest CT, a spiral trajectory with TCM was used. The effect of tube start angles on dose distribution was investigated with Monte Carlo simulations by using TCM curves with fixed start angles (0°, 90°, and 180°). Total doses for lungs, heart, and breast were calculated as the sum of the dose from localizer radiography and CT. Image noise was defined as the standard deviation of attenuation measured in 14 circular regions of interest. The Wilcoxon signed rank test, paired t test, and Friedman analysis of variance were conducted to evaluate differences in noise, TCM curves, and organ doses, respectively. Results Organ doses from localizer radiography were lower when using a PA instead of an AP projection (P = .005). The use of a PA projection resulted in higher TCM values for chest CT (P chest CT. © RSNA, 2016 Online supplemental material is available for this article.

  17. The experiment of grid characteristics for high-voltage radiography of chest

    International Nuclear Information System (INIS)

    Kim, Jung Min; Ahn, Bong Seon

    1992-01-01

    Grids can improve the diagnostic quality of chest radiography by trapping the greater part of scattered radiation thus providing more detailed chest radiographic images. It is most effective method of reduce the scatter ratio but must increase the expour factor. The benefit of use of grid is improve the contrast and the loss is increase of patient dose. In chest radiography especially hard quality high voltage radiography it will have to be considered to select the optimum grid with view point of benefit and loss. In this experiment, auther got some result of characteristics about 4 different grids with film method. 1. There was no difference the scatter ratio in case of no grid and the scatter ratio was about 60 % 2. 16 : 1 grid was excellent of scatter reduction factor in high voltage chest radiography, next was 10 : 1, CROSS, MICRO FINE grid have low scatter reduction rate compare to 16:1,10:1 grid. 3. The bucky factor of CROSS grid in accordance of kVp was find out the highest in 4 grids, on the contrary 10 : 1 grid was profitable to the. exposure does. 4. With careful consideration in the point of scatter reduction rate and bucky factor, auther suggest the 10 : 1 linear grid on the use of chest radiography in 80∼120 kVp, 16 : 1 grid in 120∼140 kVp

  18. Clinical Evaluation of a Dual-Side Readout Technique Computed Radiography System in Chest Radiography of Premature Neonates

    International Nuclear Information System (INIS)

    Carlander, A.; Hansson, J.; Soederberg, J.; Steneryd, K.; Baath, M.

    2008-01-01

    Background: Recently, the dual-side readout technique has been introduced in computed radiography, leading to an increase in detective quantum efficiency (DQE) compared with the single-side readout technique. Purpose: To evaluate if the increase in DQE with the dual-side readout technique results in a higher clinical image quality in chest radiography of premature neonates at no increase in radiation dose. Material and Methods: Twenty-four chest radiographs of premature neonates were collected from both a single-side readout technique system and a double-side readout technique system. The images were processed in the same image-processing station in order for the comparison to be only dependent on the difference in readout technique. Five radiologists rated the fulfillment of four image quality criteria, which were based on important anatomical landmarks. The given ratings were analyzed using visual grading characteristics (VGC) analysis. Results: The VGC analysis showed that the reproduction of the carina with the main bronchi and the thoracic vertebrae behind the heart was better with the dual-side readout technique, whereas no significant difference for the reproduction of the central vessels or the peripheral vessels could be observed. Conclusions: The results indicate that the higher DQE of the dual-side readout technique leads to higher clinical image quality in chest radiography of premature neonates at no increase in radiation dose. Keywords: Digital radiography; lung; observer performance; pediatrics; thorax

  19. Reproducible positioning in chest X-ray radiography

    International Nuclear Information System (INIS)

    1974-01-01

    A device is described that can be used to ensure reproducibility in the positioning of the patient during X-ray radiography of the thorax. Signals are taken from an electrocardiographic monitor and from a device recording the respiratory cycle. Radiography is performed only when two preselected signals coincide

  20. Rib Radiography versus Chest Computed Tomography in the Diagnosis of Rib Fractures.

    Science.gov (United States)

    Sano, Atsushi

    2018-05-01

     The accurate diagnosis of rib fractures is important in chest trauma. Diagnostic images following chest trauma are usually obtained via chest X-ray, chest computed tomography, or rib radiography. This study evaluated the diagnostic characteristics of rib radiography and chest computed tomography.  Seventy-five rib fracture patients who underwent both chest computed tomography and rib radiography between April 2008 and December 2013 were included. Rib radiographs, centered on the site of pain, were taken from two directions. Chest computed tomography was performed using a 16-row multidetector scanner with 5-mm slice-pitch without overlap, and axial images were visualized in a bone window.  In total, 217 rib fractures were diagnosed in 75 patients. Rib radiography missed 43 rib fractures in 24 patients. The causes were overlap with organs in 15 cases, trivial fractures in 21 cases, and injury outside the imaging range in 7 cases. Left lower rib fractures were often missed due to overlap with the heart, while middle and lower rib fractures were frequently not diagnosed due to overlap with abdominal organs. Computed tomography missed 21 rib fractures in 17 patients. The causes were horizontal fractures in 10 cases, trivial fractures in 9 cases, and insufficient breath holding in 1 case.  In rib radiography, overlap with organs and fractures outside the imaging range were characteristic reasons for missed diagnoses. In chest computed tomography, horizontal rib fractures and insufficient breath holding were often responsible. We should take these challenges into account when diagnosing rib fractures. Georg Thieme Verlag KG Stuttgart · New York.

  1. Comparison of dose and image quality of a Flat-panel detector and an image intensifier; Comparacao da dose e qualidade da imagem de um detector Flatpanel e um intensificador de imagem

    Energy Technology Data Exchange (ETDEWEB)

    Lazzaro, M.; Friedrich, B.Q.; Luz, R.M. da; Silva, A.M.M. da, E-mail: marcos.lazzaro@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil)

    2016-07-01

    With the development of new technologies, have emerged new conversion methods of X-ray image, such as flat panel detectors. The aim of this work is the comparison of entrance surface air kerma (ESAK) and image quality between an image intensifier type of detector (A) and a flat panel (B). The ESAK was obtained by placing a ionization chamber under PMMA simulators of 10, 20 and 30 cm and the image quality was obtained by using the TOR {sup 18}FG simulator. The ESAK to the equipment A is higher when compared to the equipment B. The high contrast resolution is better for the equipment A for all thicknesses of simulators. The equipment A has low contrast resolution with a better viewing threshold for thicknesses of 10 and 20 cm, and a worse performance for 30 cm. It is concluded that the equipment B has ESAK smaller and despite having lower resolution, in almost all cases, have appropriate image quality for diagnosis. (author)

  2. Non-destructive, preclinical evaluation of root canal anatomy of human teeth with flat-panel detector volume CT (FD-VCT); Zerstoerungsfreie praeklinische Evaluation der Wurzelkanalanatomie menschlicher Zaehne mittels Flaechendetektor-Volumen-CT (FD-VCT)

    Energy Technology Data Exchange (ETDEWEB)

    Heidrich, G.; Hassepass, F.; Dullin, C.; Grabbe, E. [Universitaetsklinikum Goettingen, Abt. Diagnostische Radiologie (Germany); Attin, T.; Hannig, C. [Universitaetsklinikum Goettingen, Abt. fuer Zahnerhaltung, Praeventive Zahnheilkunde und Paradontologie (Germany)

    2005-12-15

    Purpose: Successful endodontic diagnostics and therapy call for adequate depiction of the root canal anatomy with multimodal diagnostic imaging. The aim of the present study is to evaluate visualization of the endodont with flat-panel detector volume CT (FD-VCT). Materials and methods: 13 human teeth were examined with the prototype of a FD-VCT. After data acquisition and generation of volume data sets in volume rendering technology (VRT), the findings obtained were compared to conventional X-rays and cross-section preparations of the teeth. Results: The anatomical structures of the endodont such as root canals, side canals and communications between different root canals as well as dentricles could be detected precisely with FD-VCT. The length of curved root canals was also determined accurately. The spatial resolution of the system is around 140 {mu}m. Only around 73% of the main root canals detected with FD-VCT and 87% of the roots could be visualized with conventional dental X-rays. None of the side canals, shown with FD-VCT, was detectable on conventional X-rays. In all cases the enamel and dentin of the teeth could be well delineated. No differences in image quality could be discerned between stored and freshly extracted teeth, or between primary and adult teeth. (orig.)

  3. Pulmonary effects of synthetic marijuana: chest radiography and CT findings.

    Science.gov (United States)

    Berkowitz, Eugene A; Henry, Travis S; Veeraraghavan, Srihari; Staton, Gerald W; Gal, Anthony A

    2015-04-01

    The purpose of this article is to present the first chest radiographic and CT descriptions of organizing pneumonia in response to smoking synthetic marijuana. Chest radiographs showed a diffuse miliary-micronodular pattern. Chest CT images showed diffuse centrilobular nodules and tree-in-bud pattern and a histopathologic pattern of organizing pneumonia with or without patchy acute alveolar damage. This distinct imaging pattern should alert radiologists to include synthetic marijuana abuse in the differential diagnosis.

  4. A method to detect occult pneumothorax with chest radiography.

    Science.gov (United States)

    Matsumoto, Shokei; Kishikawa, Masanobu; Hayakawa, Koichi; Narumi, Atsushi; Matsunami, Katsutoshi; Kitano, Mitsuhide

    2011-04-01

    Small pneumothoraces are often not visible on supine screening chest radiographs because they develop anteriorly to the lung. These pneumothoraces are termed occult. Occult pneumothoraces account for an astonishingly high 52% to 63% of all traumatic pneumothoraces. A 19-year-old obese woman was involved in a head-on car accident. The admission anteroposterior chest radiographs were unremarkable. Because of the presence of right chest tenderness and an abrasion, we suspected the presence of a pneumothorax. Thus, we decided to take a supine oblique chest radiograph of the right side of the thorax, which clearly revealed a visceral pleural line, consistent with a diagnosis of traumatic pneumothorax. A pneumothorax may be present when a supine chest radiograph reveals either an apparent deepening of the costophrenic angle (the "deep sulcus sign") or the presence of 2 diaphragm-lung interfaces (the "double diaphragm sign"). However, in practice, supine chest radiographs have poor sensitivity for occult pneumothoraces. Oblique chest radiograph is a useful and fast screening tool that should be considered for cases of blunt chest trauma, especially when transport of critically ill patients to the computed tomographic suite is dangerous or when imminent transfer to another hospital is being arranged and early diagnosis of an occult pneumothorax is essential. Copyright © 2010 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

  5. An audit of follow-up chest radiography after coronary artery bypass graft

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, S. [Department of Cardiothoracic Surgery, Yorkshire Heart Centre, Leeds General Infirmary, Leeds (United Kingdom); O' Regan, D.J. [Department of Cardiothoracic Surgery, Yorkshire Heart Centre, Leeds General Infirmary, Leeds (United Kingdom)]. E-mail: regan@leedsth.nhs.uk

    2006-07-15

    AIM: To investigate the clinical value and audit chest radiography, which is currently undertaken as part of routine practice, in the follow-up of coronary artery bypass graft (CABG) patients. MATERIAL AND METHODS: Six hundred and sixty-six first time CABG patients were identified from the Patient Analysis and Tracking System database representing the work of a single surgeon between February 2001 and September 2005. The data regarding the clinical and radiological findings on follow-up were collected from the follow-up clinic letters and case notes. Any need for re-admission/intervention was also noted. RESULTS: Of the 666 patients, 11 died and a further 10 either refused or failed to arrive for follow-up. Chest radiography was undertaken in 645 patients. Only 13 patients (2%) were found to have an abnormality on chest radiography. In all cases this was a pleural effusion that was confirmed on clinical examination in seven patients (53.9%) patients. Only one patient needed re-admission and intervention. In this case the effusion had been noted on clinical examination. Seven patients were discharged and the remaining five were followed up with repeat chest radiography before discharge. Seventy-four patients had a respiratory complication postoperatively, but only three had any evidence of an effusion on follow-up. CONCLUSION: The diagnostic yield of a routine chest radiography in a CABG follow-up clinic is low (2%) and the need for intervention is rare and is determined by clinical examination. The practice of routine radiography in this group of patients has now stopped and follow-up audit will be conducted in 12 months.

  6. [Optimization of digital chest radiography image post-processing in diagnosis of pneumoconiosis].

    Science.gov (United States)

    Sheng, Bing-yong; Mao, Ling; Zhou, Shao-wei; Shi, Jin

    2013-11-01

    To establish the optimal image post-processing parameters for digital chest radiography as preliminary research for introducing digital radiography (DR) to pneumoconiosis diagnosis in China. A total of 204 pneumoconiosis patients and 31 dust-exposed workers were enrolled as the subjects in this research. Film-screen radiography (FSR) and DR images were taken for all subjects. DR films were printed after raw images were processed and parameters were altered using DR workstation (GE Healthcare, U.S.A.). Image gradations, lung textures, and the imaging of thoracic vertebra were evaluated by pneumoconiosis experts, and the optimal post-processing parameters were selected. Optical density was measured for both DR films and FSR films. For the DR machine used in this research, the contrast adjustment (CA) and brightness adjustment (BA) were the main parameters that determine the brightness and gray levels of images. The optimal ranges for CA and BA were 115%∼120% and 160%∼165%, respectively. The quality of DR chest films would be optimized when tissue contrast was adjusted to a maximum of 0.15, edge to a minimum of 1, and both noise reduction and tissue equalization to0.The failure rate of chest DR (0.4%) was significantly lower than that of chest FSR (17%) (P image post-processing on DR machine purchased from GE Healthcare, the DR chest films can meet all requirements for the quality of chest X-ray films in the Chinese diagnostic criteria for pneumoconiosis.

  7. [Radiation exposure of children in pediatric radiology. Part 5: organ doses in chest radiography].

    Science.gov (United States)

    Seidenbusch, M C; Schneider, K

    2009-05-01

    Reconstruction of organ doses of selected organs and tissues from radiographic settings and exposure data collected during chest X-ray examinations of children of various age groups performed in Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007. The dosimetric data of all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 119 150 chest radiographs of all age groups. Reconstruction of organ doses in 40 organs and tissues in X-ray examinations of the chest was performed based on the conversion factor concept. The radiation exposure of organs in projection radiography is determined by the exact site of the organs relative to the edges of the X-ray field and the beam direction of X-rays. Optimal collimation in chest radiography can reduce the exposure of organs located at the periphery of the X-ray field, e. g. thyroid gland, stomach and partially the liver, by a factor of 2 to 3, while organs located in the center of the X-ray-field, e. g. thymus, breasts, lungs, esophagus and red bone marrow, are not affected by exact collimation. The high frequency of the roentgen examination of the chest in early age groups increases the collective radiation burden to radiosensitive organs. Therefore, radiation protection of the patient during chest radiographies remains of great importance.

  8. Frequency of Chest Radiography and Abdominal Ultrasound in The Netherlands: 1999-2003

    International Nuclear Information System (INIS)

    Speets, Anouk M.; Kalmijn, Sandra; Hoes, Arno W.; Graaf, Yolanda der; Smeets, Hugo M.; Mali, Willem P. Th. M.

    2005-01-01

    Chest radiography and abdominal ultrasound are two widely used diagnostic imaging techniques in Western societies. However, little is known about the frequency of these examinations and its determinants. The aim of this descriptive study was to provide detailed information on the number of chest radiography and abdominal ultrasound examinations by age, gender, referring physician and ethnicity. We used data of approximately 3,000,000 sick fund insured persons of the Health Insurance Company Agis in The Netherlands from 1999 to 2003. We calculated annual numbers and corresponding 95% confidence intervals for different age, gender and ethnicity categories. The mean age of the population was 38±22 years and 46% were male. Chest radiographs were ordered in 130 per 1000 persons per year and abdominal ultrasound examinations in 39 per 1000 persons per year; these frequencies did not change noticeable over the five-year period. Chest radiography was performed more often in males (156 vs. 109 per 1,000 persons/year in females; p<0.05) and abdominal ultrasound more often in females (43 vs. 34 per 1000 persons/year in males; p<0.05). Frequencies were highest in persons aged 70-79 years. Compared to medical specialists, general practitioners more frequently referred younger patients and females, especially for abdominal ultrasound. Up to the age of 60 years the frequencies of both chest radiography and abdominal ultrasound were higher in Turks and Moroccans compared to other persons. In conclusion, this study showed marked differences in the frequencies of chest radiography and abdominal ultrasound according to age, gender and ethnicity in The Netherlands

  9. Observer training for computer-aided detection of pulmonary nodules in chest radiography

    NARCIS (Netherlands)

    de Boo, Diederick W.; van Hoorn, François; van Schuppen, Joost; Schijf, Laura; Scheerder, Maeke J.; Freling, Nicole J.; Mets, Onno; Weber, Michael; Schaefer-Prokop, Cornelia M.

    2012-01-01

    To assess whether short-term feedback helps readers to increase their performance using computer-aided detection (CAD) for nodule detection in chest radiography. The 140 CXRs (56 with a solitary CT-proven nodules and 84 negative controls) were divided into four subsets of 35; each were read in a

  10. The role of yearly chest radiography in the early detection of lung cancer following oral cancer

    NARCIS (Netherlands)

    Stalpers, L. J.; van Vierzen, P. B.; Brouns, J. J.; Bruaset, I.; Manni, J. J.; Verbeek, A. L.; Ruys, J. H.; van Daal, W. A.

    1989-01-01

    In a study of 213 patients with oral cancer, we investigated the incidence and prognosis of lung malignancies in patients offered a yearly chest radiography in the follow-up. Three conclusions can be drawn. (1) Metastatic or primary lung cancer was diagnosed in 22 (10.3%) patients. The 2-year

  11. Computed and conventional chest radiography: a comparison of image quality and radiation dose

    International Nuclear Information System (INIS)

    Ramli, K.; Abdullah, B.J.J.; Ng, K-H.; Hussain, A.F.; Mahmud, R.

    2005-01-01

    The aim of this study was to compare the image quality and entrance skin dose (ESD) for film-screen and computed chest radiography. Analysis of the image quality and dose on chest radiography was carried out on a conventional X-ray unit using film-screen, storage phosphor plates and selenium drum direct chest radiography. For each receptor, ESD was measured in 60 patients using thermoluminescent dosemeters. Images were printed on 35 x 43 cm films. Image quality was assessed subjectively by evaluation of anatomic features and estimation of the image quality, following the guidelines established by the protocols of the Commission of the European Communities. There was no statistically significant difference noted between the computed and conventional images (Wilcoxon rank sum test, P>0.05). Imaging of the mediastinum and peripheral lung structures were better visualized with the storage phosphor and selenium drum technique than with the film-screen combination. The patients' mean ESD for chest radiography using the storage phosphor, film-screen combination and selenium drum was 0.20, 0.20 and 0.25 mGy, respectively, with no statistically significant difference with P > 0.05 (χ 2 tests) Copyright (2005) Blackwell Publishing Asia Pty Ltd

  12. Digital chest tomosynthesis: the 2017 updated review of an emerging application

    Science.gov (United States)

    Ferrari, Arianna; Bertolaccini, Luca; Solli, Piergiorgio; Di Salvia, Paola Oriana

    2018-01-01

    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. Digital chest tomosynthesis (DCT), a tomographic technique, may offer an alternative to CT. DCT uses a conventional radiograph tube, a flat-panel detector, a computer-controlled tube mover and reconstruction algorithms to produce section images. It shows promise in the detection of potentially malignant lung nodules, with higher sensibility than CR, and is emerging as a low-dose and low-cost alternative to CT to improve treatment decisions. In fact, an increasing number of researchers are showing that tomosynthesis could have a role in the detection of lung cancer, in addition to its present role in breast screening. However, DCT offers some limitations, such as limited depth resolution, which may explain the difficulty in detecting pathologies in the subpleural region and the occurrence of artefacts from medical devices. Once solved these limitations and once more studies supporting its use will be available, DCT could become the first-line lung cancer screening tool among patients at considerable risk of lung cancer. PMID:29666814

  13. Intrathoracic tuberculous lymphadenopathy in children: a guide to chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    George, Anthony; Andronikou, Savvas [Bristol Royal Hospital for Children and the University of Bristol, Department of Paediatric Radiology, Bristol (United Kingdom); Pillay, Tanyia; Zar, Heather J. [University of Cape Town and Medical Research Council Unit on Child and Adolescent Health, Department of Paediatrics and Child Health, Red Cross War Memorial Children' s Hospital, Cape Town (South Africa); Goussard, Pierre [Tygerberg Hospital and the University of Stellenbosch, Department of Paediatrics and Child Health, Cape Town (South Africa)

    2017-09-15

    Making the diagnosis of pulmonary tuberculosis in children can be difficult because microbiological confirmation is not often achieved. Diagnosis is therefore often based on clinical features in combination with chest radiograph findings. Chest radiographs can demonstrate lymphadenopathy of the hilar and para-tracheal regions on the anteroposterior view, and subcarinal lymphadenopathy on the lateral view. However poor interobserver agreement has been reported for radiologist and clinician assessment of lymphadenopathy. This might reflect the lack of standardised imaging criteria for diagnosis as well as radiologists' objectives for achieving sensitivity rather than specificity. In this paper the authors provide a pictorial aid of chest radiographs in children with culture-confirmed tuberculosis to help clinicians identify lymph node enlargement in primary pulmonary tuberculosis. This collection of images comprises chest radiographs accompanied by schematics and either CT or MRI scan confirmation of pathological lymph node enlargement at the positions commonly affected in tuberculosis. (orig.)

  14. Dose-image quality study in digital chest radiography using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Correa, S.C.A.; Souza, E.M.; Silva, A.X.; Lopes, R.T.; Yoriyaz, H.

    2008-01-01

    One of the main preoccupations of diagnostic radiology is to guarantee a good image-sparing dose to the patient. In the present study, Monte Carlo simulations, with MCNPX code, coupled with an adult voxel female model (FAX) were performed to investigate how image quality and dose in digital chest radiography vary with tube voltage (80-150 kV) using air-gap technique and a computed radiography system. Calculated quantities were normalized to a fixed value of entrance skin exposure (ESE) of 0.0136 R. The results of the present analysis show that the image quality for chest radiography with imaging plate is improved and the dose reduced at lower tube voltage

  15. [TUBERCULOSIS SCREENING BY CHEST RADIOGRAPHY AMONG INTERNATIONAL STUDENTS AT JAPANESE LANGUAGE SCHOOLS IN OSAKA CITY].

    Science.gov (United States)

    Tsuda, Yuko; Matsumoto, Kenji; Komukai, Jun; Furukawa, Kanae; Saito, Kazumi; Shimouchi, Akira

    2015-10-01

    With a broader aim of controlling pulmonary tuberculosis (TB) among foreigners, here, we have reported the findings of chest radiography screening for TB among international students at Japanese language schools in Osaka city. Between April 2011 and December 2013, 4,529 international students from 19 Japanese language schools in Osaka city underwent chest radiography for TB screening. The chest radiographs were studied in reference to the student's sex, age, nationality, and date of entry to Japan as well as any health conditions present at the time of screening. We further analyzed the bacterial information and pulmonary TB classification based on chest radiography findings of students who were identified to be positive for TB. Information on the implementation of health education was also gathered. The results revealed that 52.5% of the students who underwent chest radiography came from China, 20.3 % from South Korea, and 16.3% from Vietnam. Of the students, 52.9% were male and 47.1% were female. The median age of students was 23 years (range: 14-70 years). The median number of days from the first date of entry to Japan up until the radiography screening was 63 days. Based on the chest radiography findings, 71 students (1.6%) were suspected to have TB; however, further detailed examination confirmed that 19 students (0.4%) had active TB. This percentage is significantly higher than the 0.1% TB identification rate among residents in Osaka city of the same time period (Pschools (for a total of 12 times) in the 3-year period. A total of 257 language school staff and students attended the health education seminars. The identification rate of TB positive students in Japanese language schools was higher than that of the general residents in Osaka city. In addition, most of these students came to Japan within 1 year. It is also important to note that the majority of TB positive students had sputum smear negative results. This study proves that medical examination after

  16. Comparison between radiation exposure levels using an image intensifier and a flat-panel detector-based system in image-guided central venous catheter placement in children weighing less than 10 kg

    Energy Technology Data Exchange (ETDEWEB)

    Miraglia, Roberto; Maruzzelli, Luigi; Cortis, Kelvin; Gerasia, Roberta; Maggio, Simona; Luca, Angelo [Diagnostic and Therapeutic Services, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo (Italy); Piazza, Marcello [Department of Anesthesia, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo (Italy); Tuzzolino, Fabio [Department of Information Technology, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo (Italy)

    2014-09-10

    Ultrasound-guided central venous puncture and fluoroscopic guidance during central venous catheter (CVC) positioning optimizes technical success and lowers the complication rates in children, and is therefore considered standard practice. The purpose of this study was to compare the radiation exposure levels recorded during CVC placement in children weighing less than 10 kg in procedures performed using an image intensifier-based angiographic system (IIDS) to those performed in a flat-panel detector-based interventional suite (FPDS). A retrospective review of 96 image-guided CVC placements, between January 2008 and October 2013, in 49 children weighing less than 10 kg was performed. Mean age was 8.2 ± 4.4 months (range: 1-22 months). Mean weight was 7.1 ± 2.7 kg (range: 2.5-9.8 kg). The procedures were classified into two categories: non-tunneled and tunneled CVC placement. Thirty-five procedures were performed with the IIDS (21 non-tunneled CVC, 14 tunneled CVC); 61 procedures were performed with the FPDS (47 non-tunneled CVC, 14 tunneled CVC). For non-tunneled CVC, mean DAP was 113.5 ± 126.7 cGy cm{sup 2} with the IIDS and 15.9 ± 44.6 cGy . cm{sup 2} with the FPDS (P < 0.001). For tunneled CVC, mean DAP was 84.6 ± 81.2 cGy . cm{sup 2} with the IIDS and 37.1 ± 33.5 cGy cm{sup 2} with the FPDS (P = 0.02). The use of flat-panel angiographic equipment reduces radiation exposure in small children undergoing image-guided CVC placement. (orig.)

  17. Diagnosing pulmonary edema: lung ultrasound versus chest radiography.

    Science.gov (United States)

    Martindale, Jennifer L; Noble, Vicki E; Liteplo, Andrew

    2013-10-01

    Diagnosing the underlying cause of acute dyspnea can be challenging. Lung ultrasound may help to identify pulmonary edema as a possible cause. To evaluate the ability of residents to recognize pulmonary edema on lung ultrasound using chest radiographs as a comparison standard. This is a prospective, blinded, observational study of a convenience sample of resident physicians in the Departments of Emergency Medicine (EM), Internal Medicine (IM), and Radiology. Residents were given a tutorial on interpreting pulmonary edema on both chest radiograph and lung ultrasound. They were then shown both ultrasounds and chest radiographs from 20 patients who had presented to the emergency department with dyspnea, 10 with a primary diagnosis of pulmonary edema, and 10 with alternative diagnoses. Cohen's κ values were calculated to describe the strength of the correlation between resident and gold standard interpretations. Participants included 20 EM, 20 IM, and 20 Radiology residents. The overall agreement with gold standard interpretation of pulmonary edema on lung ultrasound (74%, κ = 0.51, 95% confidence interval 0.46-0.55) was superior to chest radiographs (58%, κ = 0.25, 95% confidence interval 0.20-0.30) (P Radiology residents interpreted chest radiographs more accurately than did EM and IM residents. Residents were able to more accurately identify pulmonary edema with lung ultrasound than with chest radiograph. Physicians with minimal exposure to lung ultrasound may be able to correctly recognize pulmonary edema on lung ultrasound.

  18. Application of Deconvolution Algorithm of Point Spread Function in Improving Image Quality: An Observer Preference Study on Chest Radiography.

    Science.gov (United States)

    Chae, Kum Ju; Goo, Jin Mo; Ahn, Su Yeon; Yoo, Jin Young; Yoon, Soon Ho

    2018-01-01

    To evaluate the preference of observers for image quality of chest radiography using the deconvolution algorithm of point spread function (PSF) (TRUVIEW ART algorithm, DRTECH Corp.) compared with that of original chest radiography for visualization of anatomic regions of the chest. Prospectively enrolled 50 pairs of posteroanterior chest radiographs collected with standard protocol and with additional TRUVIEW ART algorithm were compared by four chest radiologists. This algorithm corrects scattered signals generated by a scintillator. Readers independently evaluated the visibility of 10 anatomical regions and overall image quality with a 5-point scale of preference. The significance of the differences in reader's preference was tested with a Wilcoxon's signed rank test. All four readers preferred the images applied with the algorithm to those without algorithm for all 10 anatomical regions (mean, 3.6; range, 3.2-4.0; p chest anatomical structures applied with the deconvolution algorithm of PSF was superior to the original chest radiography.

  19. The mass miniature chest radiography programme in Cape Town ...

    African Journals Online (AJOL)

    Background. Tuberculosis (TB) control programmes rely mainly on passive detection of symptomatic individuals. The resurgence of TB has rekindled interest in active case finding. Cape Town (South Africa) had a mass miniature radiography (MMR) screening programme from 1948 to 1994. Objective. To evaluate screening ...

  20. Can routine chest radiography be used to diagnose mild COPD? A nested case-control study.

    Science.gov (United States)

    den Harder, A M; Snoek, A M; Leiner, T; Suyker, W J; de Heer, L M; Budde, R P J; Lammers, J W J; de Jong, P A; Gondrie, M J A

    2017-07-01

    To determine whether mild stage chronic obstructive pulmonary disease (COPD) can be detected on chest radiography without substantial overdiagnosis. A retrospective nested case-control study (case:control, 1:1) was performed in 783 patients scheduled for cardiothoracic surgery who underwent both spirometry and a chest radiograph preoperative. Diagnostic accuracy of chest radiography for diagnosing mild COPD was investigated using objective measurements and overall appearance specific for COPD on chest radiography. Inter-observer variability was investigated and variables with a kappa >0.40 as well as baseline characteristics were used to make a diagnostic model which was aimed at achieving a high positive predictive value (PPV). Twenty percent (155/783) had COPD. The PPV of overall appearance specific for COPD alone was low (37-55%). Factors in the diagnostic model were age, type of surgery, gender, distance of the right diaphragm apex to the first rib, retrosternal space, sternodiaphragmatic angle, maximum height right diaphragm (lateral view) and subjective impression of COPD (using both views). The model resulted in a PPV of 100%, negative predictive value (NPV) of 82%, sensitivity of 10% and specificity of 100% with an area under the curve of 0.811. Detection of mild COPD without substantial overdiagnosis was not feasible on chest radiographs in our cohort. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Cause analysis of missing diagnosis for vertebral fracture on lateral chest radiography

    International Nuclear Information System (INIS)

    Yu Wei; Yao Jinpeng; Lin Qiang; Mu Wenbin

    2010-01-01

    Objective: To analyze the cause of missing diagnosis for vertebral fracture on lateral chest radiography. Methods: Lateral chest radiographies of 1638 hospitalized patients (871 males and 767 females) were retrospectively reviewed for identifying vertebral fractures. Their ages ranged from 50 to 91 years with the mean of 63.5 years. Complains and application for chest radiography in all patients were not related to osteoporosis and vertebral fracture. Vertebral fracture and fracture severity were evaluated using Genant's semiquantitative visual method, taking approximately a 20%-25% vertebral height reduction as mild grade, 26%--40% as moderate grade and 41% or greater as severe grade. Evaluation results of the vertebral fracture, original X-ray reports, as well as medical records were compared for further analysis. Results: Eighty-four in 1638 patients showed vertebral fractures on the lateral chest radiographies. Of them, vertebral fractures were reported in 30 cases and 54 patients were not reported on their original X-ray reports. There were 63 vertebral fractures in 54 un-reported patients, most of which were single fracture (75% or 47/63). Grade I fracture accounted for 54% (34/63), Grade II fracture 33% (21/63), while 13% presented grade III fracture (8/63). In all 84 patients with vertebral fractures, only 5 cases (6%) underwent dual energy X-ray absorptiometry (DXA) measurement, 5 cases (6%) were recorded to have vertebral fractures on the medical papers, as well as 15 cases (18%) were prescribed drugs related to the osteoporosis when discharged from hospital. All drugs prescribed for the 15 patients were limited only to calcium. Conclusions: More attention should be paid to osteoporosis by doctors including radiologists. Vertebral fracture on lateral chest radiography should be completely diagnosed, which is helpful for both prevention and treatment. (authors)

  2. Lung nodule detection by microdose CT versus chest radiography (standard and dual-energy subtracted).

    Science.gov (United States)

    Ebner, Lukas; Bütikofer, Yanik; Ott, Daniel; Huber, Adrian; Landau, Julia; Roos, Justus E; Heverhagen, Johannes T; Christe, Andreas

    2015-04-01

    The purpose of this study was to investigate the feasibility of microdose CT using a comparable dose as for conventional chest radiographs in two planes including dual-energy subtraction for lung nodule assessment. We investigated 65 chest phantoms with 141 lung nodules, using an anthropomorphic chest phantom with artificial lung nodules. Microdose CT parameters were 80 kV and 6 mAs, with pitch of 2.2. Iterative reconstruction algorithms and an integrated circuit detector system (Stellar, Siemens Healthcare) were applied for maximum dose reduction. Maximum intensity projections (MIPs) were reconstructed. Chest radiographs were acquired in two projections with bone suppression. Four blinded radiologists interpreted the images in random order. A soft-tissue CT kernel (I30f) delivered better sensitivities in a pilot study than a hard kernel (I70f), with respective mean (SD) sensitivities of 91.1%±2.2% versus 85.6%±5.6% (p=0.041). Nodule size was measured accurately for all kernels. Mean clustered nodule sensitivity with chest radiography was 45.7%±8.1% (with bone suppression, 46.1%±8%; p=0.94); for microdose CT, nodule sensitivity was 83.6%±9% without MIP (with additional MIP, 92.5%±6%; pmicrodose CT for readers 1, 2, 3, and 4 were 84.3%, 90.7%, 68.6%, and 45.0%, respectively. Sensitivities with chest radiography for readers 1, 2, 3, and 4 were 42.9%, 58.6%, 36.4%, and 90.7%, respectively. In the per-phantom analysis, respective sensitivities of microdose CT versus chest radiography were 96.2% and 75% (pmicrodose CT, the applied dose was 0.1323 mSv. Microdose CT is better than the combination of chest radiography and dual-energy subtraction for the detection of solid nodules between 5 and 12 mm at a lower dose level of 0.13 mSv. Soft-tissue kernels allow better sensitivities. These preliminary results indicate that microdose CT has the potential to replace conventional chest radiography for lung nodule detection.

  3. Usefulness of 2D fusion of postmortem CT and antemortem chest radiography studies for human identification.

    Science.gov (United States)

    Shinkawa, Norihiro; Hirai, Toshinori; Nishii, Ryuichi; Yukawa, Nobuhiro

    2017-06-01

    To determine the feasibility of human identification through the two-dimensional (2D) fusion of postmortem computed tomography (PMCT) and antemortem chest radiography. The study population consisted of 15 subjects who had undergone chest radiography studies more than 12 months before death. Fused images in which a chest radiograph was fused with a PMCT image were obtained for those subjects using a workstation, and the minimum distance gaps between corresponding anatomical landmarks (located at soft tissue and bone sites) in the images obtained with the two modalities were calculated. For each fused image, the mean of all these minimum distance gaps was recorded as the mean distance gap (MDG). For each subject, the MDG obtained for the same-subject fused image (i.e., where both of the images that were fused derived from that subject) was compared with the MDGs for different-subject fused images (i.e., where only one of the images that were fused derived from that subject; the other image derived from a different subject) in order to determine whether same-subject fused images can be reliably distinguished from different-subject fused images. The MDGs of the same-subject fused images were found to be significantly smaller than the MDGs of the different-subject fused images (p chest radiography and postmortem CT images may assist in human identification.

  4. Association of Aortic Calcification on Plain Chest Radiography with Obstructive Coronary Artery Disease

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yeong Han; Chang, Jeong Ho [Dept. of Diagnostic Radiology, Daegu Catholic University Hospital, Daegu (Korea, Republic of); Park, Jong Sam [Dept. of Radiologic Tecnology, Daegu Health College, Daegu (Korea, Republic of)

    2009-03-15

    This study was conducted to determine an association between aortic calcification viewed on plain chest radiography and obstructive coronary artery disease. Retrospective review of all chest radiography obtained from consecutive patients undergoing coronary angiography. Chest PA images were reviewed by technical radiologist and radiologist. Considering the presence of aortic arch calcification, images were compared with the results of coronary angiography. In addition, the size of aortic arch calcification were divided into two groups - the smaller and the larger than 10 mm. Among the total 846 patients, the number of the patients with obstructive coronary artery disease is total 417 (88.3%) in males and 312 (83.4%) in females. Considering the presence of aortic arch calcification, the positive predictive value of relation between aortic arch calcification and obstructive coronary artery disease was 91.4% and the relative risk of the group with aortic arch calcification to the opposite group was 1.10. According to the size of aortic arch calcification and obstructive coronary artery disease, the positive predictive value was 91.9% and the relative risk between two groups was 1.04. This study shows that aortic calcification was closely associated with obstructive coronary artery disease. If the aortic calcification is notified on plain chest radiography, we strongly recommend to consult with doctor.

  5. Computed radiography versus mobile direct radiography for bedside chest radiographs: Impact of dose on image quality and reader agreement

    International Nuclear Information System (INIS)

    De Boo, D.W.; Weber, M.; Deurloo, E.E.; Streekstra, G.J.; Freling, N.J.; Dongelmans, D.A.; Schaefer-Prokop, C.M.

    2011-01-01

    Aim: To asses the image quality and potential for dose reduction of mobile direct detector (DR) chest radiography as compared with computed radiography (CR) for intensive care unit (ICU) chest radiographs (CXR). Methods and materials: Three groups of age-, weight- and disease-matched ICU patients (n = 114 patients; 50 CXR per acquisition technique) underwent clinically indicated bedside CXR obtained with either CR (single read-out powder plates) or mobile DR (GOS-TFT detectors) at identical or 50% reduced dose (DR 50% ). Delineation of anatomic structures and devices used for patient monitoring, overall image quality and disease were scored by four readers. In 12 patients pairs of follow-up CR and DR images were available, and in 15 patients pairs of CR and DR 50% images were available. In these pairs the overall image quality was also compared side-by-side. Results: Delineation of anatomy in the mediastinum was scored better with DR or DR 50% than with CR. Devices used for patient monitoring were seen best with DR, with DR 50% being superior to CR. In the side-by-side comparison, the overall image quality of DR and DR 50% was rated better than CR in 96% (46/48) and 87% (52/60), respectively. Inter-observer agreement for the assessment of pathology was fair for CR and DR 50% (κ = 0.33 and κ = 0.39, respectively) and moderate for DR (κ = 0.48). Conclusion: Mobile DR units offer better image quality than CR for bedside chest radiography and allow for 50% dose reduction. Inter-observer agreement increases with image quality and is superior with DR, while DR 50% and CR are comparable.

  6. The frequency of various indications for plain chest radiography in Nnamdi Azikiwe University Teaching Hospital, Nnewi (NAUTH).

    Science.gov (United States)

    Okpala, O C; Okafor, C; Aronu, M E

    2013-01-01

    With soaring advances in the field of medicine, the place of older radiologic imaging modalities is being reduced to basic screening tools. Yet the modern imaging modalities like computerized tomography (CT), magnetic resonance imaging (MRI), ultrasound and nuclear medicine are hardly available. To study the frequency of various indications of plain chest radiography, remind us of its uses and to enhance the preparedness of the department to maximally accomplish the ideals of this investigation. A total of 1476 consecutive patients for chest radiography in the department of radiology, NAUTH, Nnewi from the period of February 2009 and whose request form contain adequate data were recruited for this study. These data were analyzed using SSPS. A total of 1476 patient were included in this study. There was female preponderance with male to female ratio of 1.3:1. Mean Age of the patients is 39.32 years (std19.56). The most frequent indication for chest radiography is certain infections and parasitic diseases (40.9% and the greatest source of referral for this study is General outpatient (GOPD)/family medicine department. The most frequent indications for chest radiography in the study are certain infection and parasitic diseases. Chest Radiography is the most frequent plain radiography study in our environment where infectious diseases are still very rampant. This makes chest radiography an important study for screening patient for possible diagnosis and classifying the need for further radiographic investigation of our patients.

  7. Nodule detection in digital chest radiography: Effect of anatomical noise

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Boerjesson, S.; Hoeschen, C.; Tischenko, O.; Kheddache, S.; Vikgren, J.; Maansson, L. G.

    2005-01-01

    The image background resulting from imaged anatomy can be divided into those components that are meaningful to the observers, in the sense that they are recognised as separate structures, and those that are not. These latter components (referred to as anatomical noise) can be removed using a method developed within the RADIUS group. The aim of the present study was to investigate whether the removal of the anatomical noise results in images where lung nodules with lower contrast can be detected. A receiver operating characteristic (ROC) study was therefore conducted using two types of images: clinical chest images and chest images in which the anatomical noise had been removed. Simulated designer nodules with a full-width-at-fifth-maximum of 10 mm but with varying contrast were added to the images. The contrast needed to obtain an area under the ROC curve of 0.80, C0.8, was used as a measure of detectability (a low value of C0.8 represents a high delectability). Five regions of the chest X ray were investigated and it was found that in all regions the removal of anatomical noise led to images with lower C0.8 than the original images. On average, C0.8 was 20% higher in the original images, ranging from 7% (the lateral pulmonary regions) to 41% (the upper mediastinal regions). (authors)

  8. SU-E-I-53: Comparison of Kerma-Area-Product Between the Micro-Angiographic Fluoroscope (MAF) and a Flat Panel Detector (FPD) as Used in Neuro-Endovascular Procedures

    International Nuclear Information System (INIS)

    Vijayan, S; Rana, V; Nagesh, S Setlur; Xiong, Z; Rudin, S; Bednarek, D

    2015-01-01

    Purpose: To determine the reduction of integral dose to the patient when using the micro-angiographic fluoroscope (MAF) compared to when using the standard flat-panel detector (FPD) for the techniques used during neurointerventional procedures. Methods: The MAF is a small field-of-view, high resolution x-ray detector which captures 1024 x 1024 pixels with an effective pixel size of 35μm and is capable of real-time imaging up to 30 frames per second. The MAF was used in neuro-interventions during those parts of the procedure when high resolution was needed and the FPD was used otherwise. The technique parameters were recorded when each detector was used and the kerma-area-product (KAP) per image frame was determined. KAP values were calculated for seven neuro interventions using premeasured calibration files of output as a function of kVp and beam filtration and included the attenuation of the patient table for the frontal projections to be more representative of integral patient dose. The air kerma at the patient entrance was multiplied by the beam area at that point to obtain the KAP values. The ranges of KAP values per frame were determined for the range of technique parameters used during the clinical procedures. To appreciate the benefit of the higher MAF resolution in the region of interventional activity, DA technique parameters were generally used with the MAF. Results: The lowest and highest values of KAP per frame for the MAF in DA mode were 4 and 50 times lower, respectively, compared to those of the FPD in pulsed fluoroscopy mode. Conclusion: The MAF was used in those parts of the clinical procedures when high resolution and image quality was essential. The integral patient dose as represented by the KAP value was substantially lower when using the MAF than when using the FPD due to the much smaller volume of tissue irradiated. This research was supported in part by Toshiba Medical Systems Corporation and NIH Grant R01EB002873

  9. SU-D-204-05: Quantitative Comparison of a High Resolution Micro-Angiographic Fluoroscopic (MAF) Detector with a Standard Flat Panel Detector (FPD) Using the New Metric of Generalized Measured Relative Object Detectability (GM-ROD)

    Energy Technology Data Exchange (ETDEWEB)

    Russ, M; Ionita, C; Bednarek, D; Rudin, S [Toshiba Stroke and Vascular Research Center, University at Buffalo (SUNY), Buffalo, NY (United States)

    2015-06-15

    Purpose: In endovascular image-guided neuro-interventions, visualization of fine detail is paramount. For example, the ability of the interventionist to visualize the stent struts depends heavily on the x-ray imaging detector performance. Methods: A study to examine the relative performance of the high resolution MAF-CMOS (pixel size 75µm, Nyquist frequency 6.6 cycles/mm) and a standard Flat Panel Detector (pixel size 194µm, Nyquist frequency 2.5 cycles/mm) detectors in imaging a neuro stent was done using the Generalized Measured Relative Object Detectability (GM-ROD) metric. Low quantum noise images of a deployed stent were obtained by averaging 95 frames obtained by both detectors without changing other exposure or geometric parameters. The square of the Fourier transform of each image is taken and divided by the generalized normalized noise power spectrum to give an effective measured task-specific signal-to-noise ratio. This expression is then integrated from 0 to each of the detector’s Nyquist frequencies, and the GM-ROD value is determined by taking a ratio of the integrals for the MAF-CMOS to that of the FPD. The lower bound of integration can be varied to emphasize high frequencies in the detector comparisons. Results: The MAF-CMOS detector exhibits vastly superior performance over the FPD when integrating over all frequencies, yielding a GM-ROD value of 63.1. The lower bound of integration was stepped up in increments of 0.5 cycles/mm for higher frequency comparisons. As the lower bound increased, the GM-ROD value was augmented, reflecting the superior performance of the MAF-CMOS in the high frequency regime. Conclusion: GM-ROD is a versatile metric that can provide quantitative detector and task dependent comparisons that can be used as a basis for detector selection. Supported by NIH Grant: 2R01EB002873 and an equipment grant from Toshiba Medical Systems Corporation.

  10. SU-E-I-53: Comparison of Kerma-Area-Product Between the Micro-Angiographic Fluoroscope (MAF) and a Flat Panel Detector (FPD) as Used in Neuro-Endovascular Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Vijayan, S; Rana, V; Nagesh, S Setlur; Xiong, Z; Rudin, S; Bednarek, D [Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY (United States)

    2015-06-15

    Purpose: To determine the reduction of integral dose to the patient when using the micro-angiographic fluoroscope (MAF) compared to when using the standard flat-panel detector (FPD) for the techniques used during neurointerventional procedures. Methods: The MAF is a small field-of-view, high resolution x-ray detector which captures 1024 x 1024 pixels with an effective pixel size of 35μm and is capable of real-time imaging up to 30 frames per second. The MAF was used in neuro-interventions during those parts of the procedure when high resolution was needed and the FPD was used otherwise. The technique parameters were recorded when each detector was used and the kerma-area-product (KAP) per image frame was determined. KAP values were calculated for seven neuro interventions using premeasured calibration files of output as a function of kVp and beam filtration and included the attenuation of the patient table for the frontal projections to be more representative of integral patient dose. The air kerma at the patient entrance was multiplied by the beam area at that point to obtain the KAP values. The ranges of KAP values per frame were determined for the range of technique parameters used during the clinical procedures. To appreciate the benefit of the higher MAF resolution in the region of interventional activity, DA technique parameters were generally used with the MAF. Results: The lowest and highest values of KAP per frame for the MAF in DA mode were 4 and 50 times lower, respectively, compared to those of the FPD in pulsed fluoroscopy mode. Conclusion: The MAF was used in those parts of the clinical procedures when high resolution and image quality was essential. The integral patient dose as represented by the KAP value was substantially lower when using the MAF than when using the FPD due to the much smaller volume of tissue irradiated. This research was supported in part by Toshiba Medical Systems Corporation and NIH Grant R01EB002873.

  11. Anatomic and energy variation of scatter compensation for digital chest radiography with Fourier deconvolution

    International Nuclear Information System (INIS)

    Floyd, C.E.; Beatty, P.T.; Ravin, C.E.

    1988-01-01

    The Fourier deconvolution algorithm for scatter compensation in digital chest radiography has been evaluated in four anatomically different regions at three energies. A shift invariant scatter distribution shape, optimized for the lung region at 140 kVp, was applied at 90 kVp and 120 kVp in the lung, retrocardiac, subdiaphragmatic, and thoracic spine regions. Scatter estimates from the deconvolution were compared with measured values. While some regional variation is apparent, the use of a shift invariant scatter distribution shape (optimized for a given energy) produces reasonable scatter compensation in the chest. A different set of deconvolution parameters were required at the different energies

  12. Limited value of interlaced ECG-gated radiography in the presence of a normal chest radiograph

    International Nuclear Information System (INIS)

    Chen, J.T.T.; Ravin, C.E.; Handel, D.

    1984-01-01

    Twenty-seven patients with normal posteroanterior and lateral chest radiographs, who were undergoing cardiac catheterization because of symptoms strongly suggesting coronary artery disease, also had posteroanterior and lateral interlaced electrocardiogram-gated radiographs made. In 14 patients, the interlaced radiography system underestimated (suggested hypokinesia) the wall motion, which was normal on cardiac catheterization. In two cases the system overestimated the wall motion, in two others it both under- and overestimated the motion, and in only nine cases was the correlation correct. These data suggest that the technique is of limited application, particularly in cases in which the routine chest radiographs are normal

  13. Optimization of chest radiography. Experimental and clinical studies using rare earths screen

    Energy Technology Data Exchange (ETDEWEB)

    Bergonzini, R; Robecchi, D; Amato, M; Gallini, R; Giugni, V

    1986-01-01

    The optimization of chest radiography is a still unresolved problem, as it must answer to various clinical requirements. Even if sometimes the choice is not difficult, it becomes hard when the best film-screen combination is needed. In order to assess the optimization image quality and exposition, different experimental and clinical conditions have been investigated referring to the various combination of screen, film and tension. The Trimax system has been chosen for our investigations, performed in two different phases: the former on an anthropomorphous chest phantom, the latter on 25 patients affected by lung interstitial diseases, mainly nodular. The results are discussed.

  14. Comparing deep learning models for population screening using chest radiography

    Science.gov (United States)

    Sivaramakrishnan, R.; Antani, Sameer; Candemir, Sema; Xue, Zhiyun; Abuya, Joseph; Kohli, Marc; Alderson, Philip; Thoma, George

    2018-02-01

    According to the World Health Organization (WHO), tuberculosis (TB) remains the most deadly infectious disease in the world. In a 2015 global annual TB report, 1.5 million TB related deaths were reported. The conditions worsened in 2016 with 1.7 million reported deaths and more than 10 million people infected with the disease. Analysis of frontal chest X-rays (CXR) is one of the most popular methods for initial TB screening, however, the method is impacted by the lack of experts for screening chest radiographs. Computer-aided diagnosis (CADx) tools have gained significance because they reduce the human burden in screening and diagnosis, particularly in countries that lack substantial radiology services. State-of-the-art CADx software typically is based on machine learning (ML) approaches that use hand-engineered features, demanding expertise in analyzing the input variances and accounting for the changes in size, background, angle, and position of the region of interest (ROI) on the underlying medical imagery. More automatic Deep Learning (DL) tools have demonstrated promising results in a wide range of ML applications. Convolutional Neural Networks (CNN), a class of DL models, have gained research prominence in image classification, detection, and localization tasks because they are highly scalable and deliver superior results with end-to-end feature extraction and classification. In this study, we evaluated the performance of CNN based DL models for population screening using frontal CXRs. The results demonstrate that pre-trained CNNs are a promising feature extracting tool for medical imagery including the automated diagnosis of TB from chest radiographs but emphasize the importance of large data sets for the most accurate classification.

  15. Pulmonary complications after bone marrow transplantation in chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, J.; Sailer, M.; Schmeiser, T.; Schumacher, K.A.; Heit, W.

    1988-01-01

    In a retrospective study chest radiographs of 87 bone marrow transplant recipients were analysed. 36 patients had pulmonary complications with lung opacifications. Interstitial changes were more frequent than air-space pneumonias. The latter were caused by bacteria and fungi only. The most common cause of pulmonary complications was cytomegalovirus pneumonia. It was characterised uniformly by a bilateral diffuse interstitial pattern. Idiopathic interstitial pneumonias were indistinguishable from CMV infection. Pneumonias caused by Epstein-Barr virus and protozoa, diffuse radiation pneumonitis and leukaemic infiltrates were rare and also associated with interstitial changes.

  16. Pulmonary complications after bone marrow transplantation in chest radiography

    International Nuclear Information System (INIS)

    Schuster, J.; Sailer, M.; Schmeiser, T.; Schumacher, K.A.; Heit, W.; Ulm Univ.

    1988-01-01

    In a retrospective study chest radiographs of 87 bone marrow transplant recipients were analysed. 36 patients had pulmonary complications with lung opacifications. Interstitial changes were more frequent than air-space pneumonias. The latter were caused by bacteria and fungi only. The most common cause of pulmonary complications was cytomegalovirus pneumonia. It was characterised uniformly by a bilateral diffuse interstitial pattern. Idiopathic interstitial pneumonias were indistinguishable from CMV infection. Pneumonias caused by Epstein-Barr virus and protozoa, diffuse radiation pneumonitis and leukaemic infiltrates were rare and also associated with interstitial changes. (orig.) [de

  17. Study of incidence and causes of repeated mass miniature radiography of chest

    Energy Technology Data Exchange (ETDEWEB)

    Tandan, S; Bhargava, S K; Sharma, H M; Ved, P K; Singh, Dhan [T.B. Demonstration and Training Centre, Agra (India)

    1976-01-01

    A study has been conducted to find out the retake rate of mass miniature radiography of chest and causes of retake. The rate has been found to be 1.96% and common causes of retake are too light or dark film and movement (motion) other than respiratory. Precautionary measures against these causes should prevent unnecessary exposure of patients to radiation and also ensure economy.

  18. Emphysema in heavy smokers with normal chest radiography

    International Nuclear Information System (INIS)

    Sashidhar, K.; Monga, S.; Suri, S.; Gulati, M.; Gupta, D.

    2002-01-01

    Purpose: To determine the severity and extent of emphysema in heavy smokers by high-resolution CT (HRCT) and to correlate the findings with spirometric tests (STs) and symptomatology. Material and Methods: Fifty adult smokers with a mean age of 53 years with a smoking history of more than 30 pack years and normal chest radiographs underwent HRCT of the chest and ST (FEV1, FEV1/FVC, PEFR). Among these, 22 had symptoms of pulmonary disease and 28 were asymptomatic. Quantification of emphysema was done using a density mask program and the visual scoring method. The results were correlated with ST and symptomatology. Results: 58% (29 out of 50) of the subjects had significant emphysema on HRCT. Eleven out of 15 with normal ST showed emphysema on HRCT while 2 with airflow obstruction on ST showed normal CT scores. 14% (4 out of 28) asymptomatic subjects had severe emphysema compared to 64% of symptomatic subjects. Emphysematous changes were predominantly seen in upper lung zones in 48% of the patients while in 52% it was distributed equally in both upper and lower zones. The number of pack years of smoking showed a positive correlation with CT scores. The correlation between HRCT scores and ST was statistically significant. Conclusion: A significant number of asymptomatic and clinically undiagnosed smokers tend to have significant emphysema. HRCT helps in early detection of disease and thus helps implementation of preventive measures

  19. An investigation of automatic exposure control calibration for chest imaging with a computed radiography system

    International Nuclear Information System (INIS)

    Moore, C S; Wood, T J; Beavis, A W; Saunderson, J R; Avery, G; Balcam, S; Needler, L

    2014-01-01

    The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQ m ), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQ m  and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma. (paper)

  20. An investigation of automatic exposure control calibration for chest imaging with a computed radiography system.

    Science.gov (United States)

    Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Beavis, A W; Saunderson, J R

    2014-05-07

    The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

  1. Validation od computational model ALDERSON/EGSnrc for chest radiography

    International Nuclear Information System (INIS)

    Muniz, Bianca C.; Santos, André L. dos; Menezes, Claudio J.M.

    2017-01-01

    To perform dose studies in situations of exposure to radiation, without exposing individuals, the numerical dosimetry uses Computational Exposure Models (ECM). Composed essentially by a radioactive source simulator algorithm, a voxel phantom representing the human anatomy and a Monte Carlo code, the ECMs must be validated to determine the reliability of the physical array representation. The objective of this work is to validate the ALDERSON / EGSnrc MCE by through comparisons between the experimental measurements obtained with the ionization chamber and virtual simulations using Monte Carlo Method to determine the ratio of the input and output radiation dose. Preliminary results of these comparisons showed that the ECM reproduced the results of the experimental measurements performed with the physical phantom with a relative error of less than 10%, validating the use of this model for simulations of chest radiographs and estimates of radiation doses in tissues in the irradiated structures

  2. Automatic anatomically selective image enhancement in digital chest radiography

    International Nuclear Information System (INIS)

    Sezan, M.I.; Minerbo, G.N.; Schaetzing, R.

    1989-01-01

    The authors develop a technique for automatic anatomically selective enhancement of digital chest radiographs. Anatomically selective enhancement is motivated by the desire to simultaneously meet the different enhancement requirements of the lung field and the mediastinum. A recent peak detection algorithm and a set of rules are applied to the image histogram to determine automatically a gray-level threshold between the lung field and mediastinum. The gray-level threshold facilitates anatomically selective gray-scale modification and/or unsharp masking. Further, in an attempt to suppress possible white-band or black-band artifacts due to unsharp masking at sharp edges, local-contrast adaptivity is incorporated into anatomically selective unsharp masking by designing an anatomy-sensitive emphasis parameter which varies asymmetrically with positive and negative values of the local image contrast

  3. Image quality in conventional chest radiography. Evaluation using the postprocessing tool Diamond View

    International Nuclear Information System (INIS)

    Niemann, Tilo; Reisinger, Clemens; Rau, Philipp; Schwarz, Jochen; Ruis-Lopez, Laura; Bongartz, Georg

    2010-01-01

    The objective of this work was to evaluate the influence of the postprocessing tool Diamond View (Siemens AG Medical Solutions, Germany) on image quality in conventional chest radiography. Evaluation of image quality remains a challenge in conventional radiography. Based on the European Commission quality criteria we evaluated the improvement of image quality when applying the new postprocessing tool Diamond View (Siemens AG Medical solutions, Germany) to conventional chest radiographs. Three different readers prospectively evaluated 102 digital image pairs of chest radiographs. Statistical analysis was performed with a p value <0.05 considered as significant. Images were evaluated on basis of the modified imaging Quality Criteria by the Commission of the European Communities. Each of the 11 image quality criteria was evaluated separately using a five point classification. Statistical analysis showed an overall tendency for improved image quality for Diamond View (DV) for all criteria. Significant differences could be found in most of the criteria. In conclusion DV improves image quality in conventional chest radiographs.

  4. Characterization and validation of the thorax phantom Lungman for dose assessment in chest radiography optimization studies.

    Science.gov (United States)

    Rodríguez Pérez, Sunay; Marshall, Nicholas William; Struelens, Lara; Bosmans, Hilde

    2018-01-01

    This work concerns the validation of the Kyoto-Kagaku thorax anthropomorphic phantom Lungman for use in chest radiography optimization. The equivalence in terms of polymethyl methacrylate (PMMA) was established for the lung and mediastinum regions of the phantom. Patient chest examination data acquired under automatic exposure control were collated over a 2-year period for a standard x-ray room. Parameters surveyed included exposure index, air kerma area product, and exposure time, which were compared with Lungman values. Finally, a voxel model was developed by segmenting computed tomography images of the phantom and implemented in PENELOPE/penEasy Monte Carlo code to compare phantom tissue-equivalent materials with materials from ICRP Publication 89 in terms of organ dose. PMMA equivalence varied depending on tube voltage, from 9.5 to 10.0 cm and from 13.5 to 13.7 cm, for the lungs and mediastinum regions, respectively. For the survey, close agreement was found between the phantom and the patients' median values (deviations lay between 8% and 14%). Differences in lung doses, an important organ for optimization in chest radiography, were below 13% when comparing the use of phantom tissue-equivalent materials versus ICRP materials. The study confirms the value of the Lungman for chest optimization studies.

  5. Diagnostic Accuracy of Ultrasonography and Radiography in Initial Evaluation of Chest Trauma Patients.

    Science.gov (United States)

    Vafaei, Ali; Hatamabadi, Hamid Reza; Heidary, Kamran; Alimohammadi, Hosein; Tarbiyat, Mohammad

    2016-01-01

    Application of chest radiography for all multiple trauma patients is associated with a significant increase in total costs, exposure to radiation, and overcrowding of the emergency department. Ultrasound has been introduced as an alternative diagnostic tool in this regard. The aim of the present study is to compare the diagnostic accuracy of chest ultrasonography and radiography in detection of traumatic intrathoracic injuries. In the present prospective cross-sectional study, patients with traumatic intrathoracic injuries, who were referred to the emergency department from December 2013 to December 2014, were assessed. The patients underwent bedside ultrasound, radiographic and computed tomography (CT) scan examinations based on ATLS recommendations. Screening performance characteristics of ultrasonography and radiography were compared using SPSS 21.0. Chest CT scan was considered as gold standard. 152 chest trauma patients with a mean age of 31.4 ± 13.8 years (range: 4 ‒ 67), were enrolled (77.6% male). Chest CT scan showed pulmonary contusion in 48 (31.6%) patients, hemothorax in 29 (19.1%), and pneumothorax in 55 (36.2%) cases. Area under the ROC curve of ultrasonography in detection of pneumothorax, hemothorax, and pulmonary contusion were 0.91 (95% CI: 0.86‒0.96), 0.86 (95% CI: 0.78‒0.94), and 0.80 (95% CI: 0.736‒0.88), respectively. Area under the ROC curve of radiography was 0.80 (95% CI: 0.736‒0.87) for detection of pneumothorax, 0.77 (95% CI: 0.68‒0.86) for hemothorax, and 0.58 (95% CI: 0.5‒0.67) for pulmonary contusion. Comparison of areas under the ROC curve declared the significant superiority of ultrasonography in detection of pneumothorax (p = 0.02) and pulmonary contusion (p < 0.001). However, the diagnostic value of the two tests was equal in detection of hemothorax (p = 0.08). The results of the present study showed that ultrasonography is preferable to radiography in the initial evaluation of patients with traumatic injuries to the

  6. Diagnostic Accuracy of Ultrasonography and Radiography in Initial Evaluation of Chest Trauma Patients

    Directory of Open Access Journals (Sweden)

    Ali Vafaei

    2016-01-01

    Full Text Available Introduction: Application of chest radiography for all multiple trauma patients is associated with a significant increase in total costs, exposure to radiation, and overcrowding of the emergency department. Ultrasound has been introduced as an alternative diagnostic tool in this regard. The aim of the present study is to compare the diagnostic accuracy of chest ultrasonography and radiography in detection of traumatic intrathoracic injuries. Methods: In the present prospective cross-sectional study, patients with traumatic intrathoracic injuries, who were referred to the emergency department from December 2013 to December 2014, were assessed. The patients underwent bedside ultrasound, radiographic and computed tomography (CT scan examinations based on ATLS recommendations. Screening performance characteristics of ultrasonography and radiography were compared using SPSS 21.0. Chest CT scan was considered as gold standard. Results: 152 chest trauma patients with a mean age of 31.4 ± 13.8 years (range: 4 ‒ 67, were enrolled (77.6% male. Chest CT scan showed pulmonary contusion in 48 (31.6% patients, hemothorax in 29 (19.1%, and pneumothorax in 55 (36.2% cases. Area under the ROC curve of ultrasonography in detection of pneumothorax, hemothorax, and pulmonary contusion were 0.91 (95% CI: 0.86‒0.96, 0.86 (95% CI: 0.78‒0.94, and 0.80 (95% CI: 0.736‒0.88, respectively. Area under the ROC curve of radiography was 0.80 (95% CI: 0.736‒0.87 for detection of pneumothorax, 0.77 (95% CI: 0.68‒0.86 for hemothorax, and 0.58 (95% CI: 0.5‒0.67 for pulmonary contusion. Comparison of areas under the ROC curve declared the significant superiority of ultrasonography in detection of pneumothorax (p = 0.02 and pulmonary contusion (p < 0.001. However, the diagnostic value of the two tests was equal in detection of hemothorax (p = 0.08. Conclusion: The results of the present study showed that ultrasonography is preferable to radiography in the initial

  7. Impact of matrix size on observer performance in digital chest radiography

    International Nuclear Information System (INIS)

    Koelblinger, C.

    2003-02-01

    This thesis compared the observer performance in the detection of abnormalities on 2k matrix(0,2 mm pixel size) and 4k matrix (0,1 mm pixel size) digital chest radiographs. Eighty five patients who underwent CT of the thorax were prospectively reccruited into the study. A chest x-ray of each patient was acquired in 2k and 4k format and four readers analyzed the images by different criterias. On the one hand a ROC analysis was performed with the CT data as goldstandard. On the other hand each reader had to rate different anatomical structures in a direct comparison of the pictures. The results of the ratings did not show any significant difference between the 2k and the 4k format. The conclusion or this study is that the use of a 4k instead of a 2k matrix in digital chest radiography does not yield to an improved observer performance. (author)

  8. Association of pneumonia and lung cancer: the value of convalescent chest radiography and follow-up

    International Nuclear Information System (INIS)

    Holmberg, H.; Kragsbjerg, P.

    1993-01-01

    A retrospective study of 1011 hospitalized patients with pneumonia was undertaken to assess the value of routine convalescent chest radiography for detection of underlying lung cancer. To investigate the mode of clinical onset of pulmonary carcinoma, 232 inpatients with this diagnosis were also studied. The findings may be summarized as follows: 1. 13/1011 pneumonia patients were found to have previously undiagnosed pulmonary carcinoma; 2. many of these carcinomas (8/13) were disclosed by an acute chest X-ray; 3. pulmonary carcinoma was found by convalescent chest X-ray in 2/88 patients not feeling well and in 2/524 patients feeling well at follow-up, and non of these 4 patients benefitted from the carcinoma diagnosis; 4. ESR was of no value in detecting underlying pulmonary carcinoma at follow-up in patients with pneumonia; 5. of the 232 patients with pulmonary carcinoma, 29 (12.5%) presented with an acute respiratory tract infection; 6. most of these latter patients did not recover as expected and their correct diagnosis was made based on a chest X-ray performed because of persistent symptoms. We suggest that patients with radiologically verified pneumonia undergo clinical examination or are interviewed 4-5 weeks after the onset. If signs or symptoms of respiratory disease persist, chest X-ray should be performed. We consider, however, that routine convalescent chest radiography with the aim of detecting any underlying pulmonary tumour could be omitted if the patient has completely recovered 1 month after the acute onset of illness. (9 refs.)

  9. Computed tomographic evaluation of pulmonary mass lesion in chest radiography

    International Nuclear Information System (INIS)

    Choe, Kyu Ok

    1984-01-01

    Until recently, solitary coin lesion of pulmonary disease has been a conspicuous problem in radiologic diagnosis. It is now well informed that CT has offered high resolution with its objective CT numbers to provide additional information in terms of anatomic and pathologic changes. Here by the aid of CT, the authors has retrospectively patients with various shape of round masses thus illustrating the advantage of it over conventional X-ray in diagnosis. 1. Total 53 patients, including 34 males and 19 females, aging between 19 to 76 years old with nodule or mass of any size ranging 1 to 13 cm in diameter were observed. 2. On plain chest X-ray they were identified where 50 patients has single round nodular or mass, only one had two masses which were ecchinococcal cysts, and the rest two had invisible lesions, only detected by CT. 3. With philips tomoscan 310, CT scan was taken 12 mm thicken slice during quiet respiration. Using the ROI cursor the average CT number of the central area was calculated 1.0 cm in side the outer border of the mass. 4. As a consequence of their pathologic features, they were itemized to 4 group as 36 solid, 9 cystic, 4 consolidative and 4 cavitary lesions. 5. Correct diagnosis of 3 cystic lesions, 4 diffuse calcification, 1 A-V malformation were available by CT densitometry. 6. By the aid of better resolution and additional cross-sectional orientation of CT, 3 extrapulmonary lesions, 3 segmental consolidations, 2 bronchocele, and 2 solitary metastasis, were helpful in diagnosis. 7. Also helpful in determining the extent of intrathoracic extent of bronchogenic carcinoma for the same reason but given clues were not more than the ordinary. 8. However, the limitation of the CT densitometry led to miss diagnosis of 3 examples of cystic vs.solid lesions, and CT density of noncalcified granuloma together with bronchogenic carcinoma, did not have a clear cut separation in between.

  10. Observer training for computer-aided detection of pulmonary nodules in chest radiography.

    Science.gov (United States)

    De Boo, Diederick W; van Hoorn, François; van Schuppen, Joost; Schijf, Laura; Scheerder, Maeke J; Freling, Nicole J; Mets, Onno; Weber, Michael; Schaefer-Prokop, Cornelia M

    2012-08-01

    To assess whether short-term feedback helps readers to increase their performance using computer-aided detection (CAD) for nodule detection in chest radiography. The 140 CXRs (56 with a solitary CT-proven nodules and 84 negative controls) were divided into four subsets of 35; each were read in a different order by six readers. Lesion presence, location and diagnostic confidence were scored without and with CAD (IQQA-Chest, EDDA Technology) as second reader. Readers received individual feedback after each subset. Sensitivity, specificity and area under the receiver-operating characteristics curve (AUC) were calculated for readings with and without CAD with respect to change over time and impact of CAD. CAD stand-alone sensitivity was 59 % with 1.9 false-positives per image. Mean AUC slightly increased over time with and without CAD (0.78 vs. 0.84 with and 0.76 vs. 0.82 without CAD) but differences did not reach significance. The sensitivity increased (65 % vs. 70 % and 66 % vs. 70 %) and specificity decreased over time (79 % vs. 74 % and 80 % vs. 77 %) but no significant impact of CAD was found. Short-term feedback does not increase the ability of readers to differentiate true- from false-positive candidate lesions and to use CAD more effectively. • Computer-aided detection (CAD) is increasingly used as an adjunct for many radiological techniques. • Short-term feedback does not improve reader performance with CAD in chest radiography. • Differentiation between true- and false-positive CAD for low conspicious possible lesions proves difficult. • CAD can potentially increase reader performance for nodule detection in chest radiography.

  11. Preliminary report from the World Health Organisation Chest Radiography in Epidemiological Studies project

    Energy Technology Data Exchange (ETDEWEB)

    Mahomed, Nasreen [University of the Witwatersrand, Department of Radiology, Johannesburg (South Africa); University of the Witwatersrand, Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Johannesburg (South Africa); Fancourt, Nicholas [Johns Hopkins Bloomberg School of Public Health, Baltimore (United States); Murdoch Children' s Research Institute, Melbourne (Australia); De Campo, John; De Campo, Margaret [Murdoch Children' s Research Institute, Melbourne (Australia); Melbourne University, Melbourne (Australia); Akano, Aliu [Department of Radiology National Hospital, Abuja (Nigeria); Medical Research Council, Gambia (South Africa); Cherian, Thomas [World Health Organization, Geneva (Switzerland); Cohen, Olivia G. [Johns Hopkins Bloomberg School of Public Health, Baltimore (United States); World Health Organization, Geneva (Switzerland); Greenberg, David [Soroka University Medical Center, Beer-Sheva (Israel); Lacey, Stephen [Murdoch Children' s Research Institute, Melbourne (Australia); Kohli, Neera [King George Medical University, Lucknow (India); Lederman, Henrique M. [Paulista School of Medicine, Hospital Sao Paulo, Sao Paulo (Brazil); Madhi, Shabir A. [University of the Witwatersrand, Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Johannesburg (South Africa); University of the Witwatersrand, Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Johannesburg (South Africa); Manduku, Veronica [Kenya Medical Research Institute (KEMRI), Nairobi (Kenya); McCollum, Eric D. [Johns Hopkins School of Medicine, Eudowood Division of Pediatric Respiratory Sciences, Baltimore (United States); Johns Hopkins Bloomberg School of Public Health, Baltimore (United States); Park, Kate [Oxford University Hospitals NHS Foundation Trust, Oxford (United Kingdom); Ribo-Aristizabal, Jose Luis [Hospital Sant Joan de Deu, Barcelona (Spain); Bar-Zeev, Naor [University of Malawi, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre (Malawi); University of Liverpool, Centre for Global Vaccine Research, Liverpool (United Kingdom); O' Brien, Katherine L. [Johns Hopkins Bloomberg School of Public Health, Baltimore (United States); Mulholland, Kim [Murdoch Children' s Research Institute, Melbourne (Australia); London School of Hygiene and Tropical Medicine, London (United Kingdom)

    2017-10-15

    Childhood pneumonia is among the leading infectious causes of mortality in children younger than 5 years of age globally. Streptococcus pneumoniae (pneumococcus) is the leading infectious cause of childhood bacterial pneumonia. The diagnosis of childhood pneumonia remains a critical epidemiological task for monitoring vaccine and treatment program effectiveness. The chest radiograph remains the most readily available and common imaging modality to assess childhood pneumonia. In 1997, the World Health Organization Radiology Working Group was established to provide a consensus method for the standardized definition for the interpretation of pediatric frontal chest radiographs, for use in bacterial vaccine efficacy trials in children. The definition was not designed for use in individual patient clinical management because of its emphasis on specificity at the expense of sensitivity. These definitions and endpoint conclusions were published in 2001 and an analysis of observer variation for these conclusions using a reference library of chest radiographs was published in 2005. In response to the technical needs identified through subsequent meetings, the World Health Organization Chest Radiography in Epidemiological Studies (CRES) project was initiated and is designed to be a continuation of the World Health Organization Radiology Working Group. The aims of the World Health Organization CRES project are to clarify the definitions used in the World Health Organization defined standardized interpretation of pediatric chest radiographs in bacterial vaccine impact and pneumonia epidemiological studies, reinforce the focus on reproducible chest radiograph readings, provide training and support with World Health Organization defined standardized interpretation of chest radiographs and develop guidelines and tools for investigators and site staff to assist in obtaining high-quality chest radiographs. (orig.)

  12. Preliminary report from the World Health Organisation Chest Radiography in Epidemiological Studies project.

    Science.gov (United States)

    Mahomed, Nasreen; Fancourt, Nicholas; de Campo, John; de Campo, Margaret; Akano, Aliu; Cherian, Thomas; Cohen, Olivia G; Greenberg, David; Lacey, Stephen; Kohli, Neera; Lederman, Henrique M; Madhi, Shabir A; Manduku, Veronica; McCollum, Eric D; Park, Kate; Ribo-Aristizabal, Jose Luis; Bar-Zeev, Naor; O'Brien, Katherine L; Mulholland, Kim

    2017-10-01

    Childhood pneumonia is among the leading infectious causes of mortality in children younger than 5 years of age globally. Streptococcus pneumoniae (pneumococcus) is the leading infectious cause of childhood bacterial pneumonia. The diagnosis of childhood pneumonia remains a critical epidemiological task for monitoring vaccine and treatment program effectiveness. The chest radiograph remains the most readily available and common imaging modality to assess childhood pneumonia. In 1997, the World Health Organization Radiology Working Group was established to provide a consensus method for the standardized definition for the interpretation of pediatric frontal chest radiographs, for use in bacterial vaccine efficacy trials in children. The definition was not designed for use in individual patient clinical management because of its emphasis on specificity at the expense of sensitivity. These definitions and endpoint conclusions were published in 2001 and an analysis of observer variation for these conclusions using a reference library of chest radiographs was published in 2005. In response to the technical needs identified through subsequent meetings, the World Health Organization Chest Radiography in Epidemiological Studies (CRES) project was initiated and is designed to be a continuation of the World Health Organization Radiology Working Group. The aims of the World Health Organization CRES project are to clarify the definitions used in the World Health Organization defined standardized interpretation of pediatric chest radiographs in bacterial vaccine impact and pneumonia epidemiological studies, reinforce the focus on reproducible chest radiograph readings, provide training and support with World Health Organization defined standardized interpretation of chest radiographs and develop guidelines and tools for investigators and site staff to assist in obtaining high-quality chest radiographs.

  13. Preliminary report from the World Health Organisation Chest Radiography in Epidemiological Studies project

    International Nuclear Information System (INIS)

    Mahomed, Nasreen; Fancourt, Nicholas; De Campo, John; De Campo, Margaret; Akano, Aliu; Cherian, Thomas; Cohen, Olivia G.; Greenberg, David; Lacey, Stephen; Kohli, Neera; Lederman, Henrique M.; Madhi, Shabir A.; Manduku, Veronica; McCollum, Eric D.; Park, Kate; Ribo-Aristizabal, Jose Luis; Bar-Zeev, Naor; O'Brien, Katherine L.; Mulholland, Kim

    2017-01-01

    Childhood pneumonia is among the leading infectious causes of mortality in children younger than 5 years of age globally. Streptococcus pneumoniae (pneumococcus) is the leading infectious cause of childhood bacterial pneumonia. The diagnosis of childhood pneumonia remains a critical epidemiological task for monitoring vaccine and treatment program effectiveness. The chest radiograph remains the most readily available and common imaging modality to assess childhood pneumonia. In 1997, the World Health Organization Radiology Working Group was established to provide a consensus method for the standardized definition for the interpretation of pediatric frontal chest radiographs, for use in bacterial vaccine efficacy trials in children. The definition was not designed for use in individual patient clinical management because of its emphasis on specificity at the expense of sensitivity. These definitions and endpoint conclusions were published in 2001 and an analysis of observer variation for these conclusions using a reference library of chest radiographs was published in 2005. In response to the technical needs identified through subsequent meetings, the World Health Organization Chest Radiography in Epidemiological Studies (CRES) project was initiated and is designed to be a continuation of the World Health Organization Radiology Working Group. The aims of the World Health Organization CRES project are to clarify the definitions used in the World Health Organization defined standardized interpretation of pediatric chest radiographs in bacterial vaccine impact and pneumonia epidemiological studies, reinforce the focus on reproducible chest radiograph readings, provide training and support with World Health Organization defined standardized interpretation of chest radiographs and develop guidelines and tools for investigators and site staff to assist in obtaining high-quality chest radiographs. (orig.)

  14. Comparison of chest radiography, chest digital tomosynthesis and low dose MDCT to detect small ground-glass opacity nodules: an anthropomorphic chest phantom study

    International Nuclear Information System (INIS)

    Doo, Kyung Won; Kang, Eun-Young; Yong, Hwan Seok; Ham, Soo-Youn; Lee, Ki Yeol; Choo, Ji Yung

    2014-01-01

    The purpose of this study was to evaluate the diagnostic performance of chest radiography (CXR), chest digital tomosynthesis (DT) and low dose multidetector computed tomography (LDCT) for the detection of small pulmonary ground-glass opacity (GGO) nodules, using an anthropomorphic chest phantom. Artificial pulmonary nodules were placed in a phantom and a total of 40 samples of different nodule settings underwent CXR, DT and LDCT. The images were randomly read by three experienced chest radiologists. Free-response receiver-operating characteristics (FROC) were used. The figures of merit for the FROC curves averaged for the three observers were 0.41, 0.37 and 0.76 for CXR, DT and LDCT, respectively. FROC analyses revealed significantly better performance of LDCT over CXR or DT for the detection of GGO nodules (P < 0.05). The difference in detectability between CXR and DT was not statistically significant (P = 0.73). The diagnostic performance of DT for the detection of pulmonary small GGO nodules was not significantly different from that of CXR, but LDCT performed significantly better than both CXR and DT. DT is not a suitable alternative to CT for small GGO nodule detection, and LDCT remains the method of choice for this purpose. (orig.)

  15. Comparison of chest radiography, chest digital tomosynthesis and low dose MDCT to detect small ground-glass opacity nodules: an anthropomorphic chest phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Doo, Kyung Won; Kang, Eun-Young; Yong, Hwan Seok [Korea University Guro Hospital, Korea University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Ham, Soo-Youn [Korea University Anam Hospital, Korea University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Lee, Ki Yeol; Choo, Ji Yung [Korea University Ansan Hospital, Korea University College of Medicine, Department of Radiology, Ansan (Korea, Republic of)

    2014-12-15

    The purpose of this study was to evaluate the diagnostic performance of chest radiography (CXR), chest digital tomosynthesis (DT) and low dose multidetector computed tomography (LDCT) for the detection of small pulmonary ground-glass opacity (GGO) nodules, using an anthropomorphic chest phantom. Artificial pulmonary nodules were placed in a phantom and a total of 40 samples of different nodule settings underwent CXR, DT and LDCT. The images were randomly read by three experienced chest radiologists. Free-response receiver-operating characteristics (FROC) were used. The figures of merit for the FROC curves averaged for the three observers were 0.41, 0.37 and 0.76 for CXR, DT and LDCT, respectively. FROC analyses revealed significantly better performance of LDCT over CXR or DT for the detection of GGO nodules (P < 0.05). The difference in detectability between CXR and DT was not statistically significant (P = 0.73). The diagnostic performance of DT for the detection of pulmonary small GGO nodules was not significantly different from that of CXR, but LDCT performed significantly better than both CXR and DT. DT is not a suitable alternative to CT for small GGO nodule detection, and LDCT remains the method of choice for this purpose. (orig.)

  16. Improving Abnormality Detection on Chest Radiography Using Game-Like Reinforcement Mechanics.

    Science.gov (United States)

    Chen, Po-Hao; Roth, Howard; Galperin-Aizenberg, Maya; Ruutiainen, Alexander T; Gefter, Warren; Cook, Tessa S

    2017-11-01

    Despite their increasing prevalence, online textbooks, question banks, and digital references focus primarily on explicit knowledge. Implicit skills such as abnormality detection require repeated practice on clinical service and have few digital substitutes. Using mechanics traditionally deployed in video games such as clearly defined goals, rapid-fire levels, and narrow time constraints may be an effective way to teach implicit skills. We created a freely available, online module to evaluate the ability of individuals to differentiate between normal and abnormal chest radiographs by implementing mechanics, including instantaneous feedback, rapid-fire cases, and 15-second timers. Volunteer subjects completed the modules and were separated based on formal experience with chest radiography. Performance between training and testing sets were measured for each group, and a survey was administered after each session. The module contained 74 cases and took approximately 20 minutes to complete. Thirty-two cases were normal radiographs and 56 cases were abnormal. Of the 60 volunteers recruited, 25 were "never trained" and 35 were "previously trained." "Never trained" users scored 21.9 out of 37 during training and 24.0 out of 37 during testing (59.1% vs 64.9%, P value online module may improve the abnormality detection rates of novice interpreters of chest radiography, although experienced interpreters are less likely to derive similar benefits. Users reviewed the educational module favorably. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  17. Tropical pulmonary eosinophilia: a comparative evaluation of plain chest radiography and computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu Manavijit; Mukhopadhyay Sima; Sharma, S.K. [All India Inst. of Medical Sciences, New Delhi (India). Dept. of Nuclear Medicine

    1996-02-01

    Plain chest radiography and computed tomography (CT) of the chest were performed on 10 patients with tropical pulmonary eosinophilia (TPE). Chest radiographs revealed bilateral diffuse lesions in the lungs of all the patients with relative sparing of lower lobes in one patient. However, computed tomography revealed bilateral diffuse lung lesions in all of the patients with relative sparing of lower lobes in three patients. In seven (70%) of the 10 patients, CT provided additional information. Computed tomography was found to be superior for the detection of reticulonodular pattern, bronchiectasis, air trapping, calcification and mediastinal adenopathy. No correlation was found between pulmonary function and gas exchange data using CT densities. There was also no correlation between the absolute eosinophil count (AEC) and the radiological severity of lesions. In six patients, high-resolution CT (HRCT) was performed in addition to conventional CT (CCT), and nodularity of lesions was better appreciated in these patients. It is concluded from this study that CT is superior to plain radiography for the evaluation of patients with TPE. 17 refs., 2 tabs., 4 figs.

  18. Detection of rib fractures in minor chest injuries: a comparison between ultrasonography and radiography performed on the same day

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Soo; Back, Chang Hee; Lee, Kyung Rae; Shin, Yun Hack; Whang, Yeong Seop; Jeong, Ku Young [Yeosu Baek Hospital, Yeosu (Korea, Republic of); Chung, Soo Hyun [NamWon Medical Center, NamWon (Korea, Republic of); Whang, Cheol Mog [Konyang University Hospital, Daejeon (Korea, Republic of)

    2007-04-15

    We wished to compare the ability of ultrasonography and radiography performed on the same day to detect rib fractures in minor chest injuries. Two hundred and fifteen patients with minor chest injuries were selected. Radiography and ultrasonography were performed on the same day with these patients. Chest wall pain was the only presenting symptom. Two radiologists performed ultrasonography. Fractures were identified by a disruption of the anterior margin of the rib and costal cartilage. The incidence and location of fractures and complications revealed by radiography and ultrasonography were compared. Radiographs revealed the presence of 70 rib fractures in 50 (23%) of 215 patients and ultrasonography revealed the presence of 203 rib fractures in 133 (62%) of 215 patients. Ultrasonography uniquely identified 133 rib fractures in 83 patients. Ultrasonography identified a 2.9 fold increase in the number of fractures in a 2.6 fold number of subjects as compared to radiography. Of the 203 sonographically detected fractures, 201 were located in the rib, one was located at the costochondral junction, and one in the costal cartilage. There were no complications seen by either radiography or ultrasonography. Ultrasonography reveals more fractures than those that may be overlooked on radiography for minor chest injuries.

  19. Detection of rib fractures in minor chest injuries: a comparison between ultrasonography and radiography performed on the same day

    International Nuclear Information System (INIS)

    Cho, Yong Soo; Back, Chang Hee; Lee, Kyung Rae; Shin, Yun Hack; Whang, Yeong Seop; Jeong, Ku Young; Chung, Soo Hyun; Whang, Cheol Mog

    2007-01-01

    We wished to compare the ability of ultrasonography and radiography performed on the same day to detect rib fractures in minor chest injuries. Two hundred and fifteen patients with minor chest injuries were selected. Radiography and ultrasonography were performed on the same day with these patients. Chest wall pain was the only presenting symptom. Two radiologists performed ultrasonography. Fractures were identified by a disruption of the anterior margin of the rib and costal cartilage. The incidence and location of fractures and complications revealed by radiography and ultrasonography were compared. Radiographs revealed the presence of 70 rib fractures in 50 (23%) of 215 patients and ultrasonography revealed the presence of 203 rib fractures in 133 (62%) of 215 patients. Ultrasonography uniquely identified 133 rib fractures in 83 patients. Ultrasonography identified a 2.9 fold increase in the number of fractures in a 2.6 fold number of subjects as compared to radiography. Of the 203 sonographically detected fractures, 201 were located in the rib, one was located at the costochondral junction, and one in the costal cartilage. There were no complications seen by either radiography or ultrasonography. Ultrasonography reveals more fractures than those that may be overlooked on radiography for minor chest injuries

  20. Prevalence and Clinical Import of Thoracic Injury Identified by Chest Computed Tomography but Not Chest Radiography in Blunt Trauma: Multicenter Prospective Cohort Study.

    Science.gov (United States)

    Langdorf, Mark I; Medak, Anthony J; Hendey, Gregory W; Nishijima, Daniel K; Mower, William R; Raja, Ali S; Baumann, Brigitte M; Anglin, Deirdre R; Anderson, Craig L; Lotfipour, Shahram; Reed, Karin E; Zuabi, Nadia; Khan, Nooreen A; Bithell, Chelsey A; Rowther, Armaan A; Villar, Julian; Rodriguez, Robert M

    2015-12-01

    Chest computed tomography (CT) diagnoses more injuries than chest radiography, so-called occult injuries. Wide availability of chest CT has driven substantial increase in emergency department use, although the incidence and clinical significance of chest CT findings have not been fully described. We determine the frequency, severity, and clinical import of occult injury, as determined by changes in management. These data will better inform clinical decisions, need for chest CT, and odds of intervention. Our sample included prospective data (2009 to 2013) on 5,912 patients at 10 Level I trauma center EDs with both chest radiography and chest CT at physician discretion. These patients were 40.6% of 14,553 enrolled in the parent study who had either chest radiography or chest CT. Occult injuries were pneumothorax, hemothorax, sternal or greater than 2 rib fractures, pulmonary contusion, thoracic spine or scapula fracture, and diaphragm or great vessel injury found on chest CT but not on preceding chest radiography. A priori, we categorized thoracic injuries as major (having invasive procedures), minor (observation or inpatient pain control >24 hours), or of no clinical significance. Primary outcome was prevalence and proportion of occult injury with major interventions of chest tube, mechanical ventilation, or surgery. Secondary outcome was minor interventions of admission rate or observation hours because of occult injury. Two thousand forty-eight patients (34.6%) had chest injury on chest radiography or chest CT, whereas 1,454 of these patients (71.0%, 24.6% of all patients) had occult injury. Of these, in 954 patients (46.6% of injured, 16.1% of total), chest CT found injuries not observed on immediately preceding chest radiography. In 500 more patients (24.4% of injured patients, 8.5% of all patients), chest radiography found some injury, but chest CT found occult injury. Chest radiography found all injuries in only 29.0% of injured patients. Two hundred and two

  1. Comparison of digital tomosynthesis and chest radiography for the detection of pulmonary nodules: systematic review and meta-analysis.

    Science.gov (United States)

    Kim, Jun H; Lee, Kyung H; Kim, Kyoung-Tae; Kim, Hyun J; Ahn, Hyeong S; Kim, Yeo J; Lee, Ha Y; Jeon, Yong S

    2016-12-01

    To compare the diagnostic accuracy of digital tomosynthesis (DTS) with that of chest radiography for the detection of pulmonary nodules by meta-analysis. A systematic literature search was performed to identify relevant original studies from 1 January 1 1976 to 31 August 31 2016. The quality of included studies was assessed by quality assessment of diagnostic accuracy studies-2. Per-patient data were used to calculate the sensitivity and specificity and per-lesion data were used to calculate the detection rate. Summary receiver-operating characteristic curves were drawn for pulmonary nodule detection. 16 studies met the inclusion criteria. 1017 patients on a per-patient basis and 2159 lesions on a per-lesion basis from 16 eligible studies were evaluated. The pooled patient-based sensitivity of DTS was 0.85 [95% confidence interval (CI) 0.83-0.88] and the specificity was 0.95 (0.93-0.96). The pooled sensitivity and specificity of chest radiography were 0.47 (0.44-0.51) and 0.37 (0.34-0.40), respectively. The per-lesion detection rate was 2.90 (95% CI 2.63-3.19). DTS has higher diagnostic accuracy than chest radiography for detection of pulmonary nodules. Chest radiography has low sensitivity but similar specificity, comparable with that of DTS. Advances in knowledge: DTS has higher diagnostic accuracy than chest radiography for the detection of pulmonary nodules.

  2. A comparison of digital tomosynthesis and chest radiography in evaluating airway lesions using computed tomography as a reference

    International Nuclear Information System (INIS)

    Choo, Ji Yung; Lee, Ki Yeol; Choi, Jung Won; Yu, Ami; Kim, Je-Hyeong; Lee, Seung Heon; Kang, Eun-Young; Oh, Yu Whan

    2016-01-01

    To compare the diagnostic performance of digital tomosynthesis (DTS) and chest radiography for detecting airway abnormalities, using computed tomography (CT) as a reference. We evaluated 161 data sets from 149 patients (91 with and 70 without airway abnormalities) who had undergone radiography, DTS, and CT to detect airway problems. Radiographs and DTS were evaluated to localize and score the severity of the airway abnormalities, and to score the image quality using CT as a reference. Receiver operating characteristics (ROC), McNemar's test, weighted kappa, and the paired t-test were used for statistical analysis. The sensitivity of DTS was higher (reader 1, 93.51 %; reader 2, 94.29 %) than chest radiography (68.83 %; 71.43 %) in detecting airway lesions. The diagnostic accuracy of DTS (90.91 %; 94.70 %) was also significantly better than that of radiography (78.03 %; 82.58 %, all p < 0.05). DTS image quality was significantly better than chest radiography (1.83, 2.74; p < 0.05) in the results of both readers. The inter-observer agreement with respect to DTS findings was moderate and superior when compared to radiography findings. DTS is a more accurate and sensitive modality than radiography for detecting airway lesions that are easily obscured by soft tissue structures in the mediastinum. (orig.)

  3. A computerized scheme for lung nodule detection in multiprojection chest radiography

    International Nuclear Information System (INIS)

    Guo Wei; Li Qiang; Boyce, Sarah J.; McAdams, H. Page; Shiraishi, Junji; Doi, Kunio; Samei, Ehsan

    2012-01-01

    Purpose: Our previous study indicated that multiprojection chest radiography could significantly improve radiologists' performance for lung nodule detection in clinical practice. In this study, the authors further verify that multiprojection chest radiography can greatly improve the performance of a computer-aided diagnostic (CAD) scheme. Methods: Our database consisted of 59 subjects, including 43 subjects with 45 nodules and 16 subjects without nodules. The 45 nodules included 7 real and 38 simulated ones. The authors developed a conventional CAD scheme and a new fusion CAD scheme to detect lung nodules. The conventional CAD scheme consisted of four steps for (1) identification of initial nodule candidates inside lungs, (2) nodule candidate segmentation based on dynamic programming, (3) extraction of 33 features from nodule candidates, and (4) false positive reduction using a piecewise linear classifier. The conventional CAD scheme processed each of the three projection images of a subject independently and discarded the correlation information between the three images. The fusion CAD scheme included the four steps in the conventional CAD scheme and two additional steps for (5) registration of all candidates in the three images of a subject, and (6) integration of correlation information between the registered candidates in the three images. The integration step retained all candidates detected at least twice in the three images of a subject and removed those detected only once in the three images as false positives. A leave-one-subject-out testing method was used for evaluation of the performance levels of the two CAD schemes. Results: At the sensitivities of 70%, 65%, and 60%, our conventional CAD scheme reported 14.7, 11.3, and 8.6 false positives per image, respectively, whereas our fusion CAD scheme reported 3.9, 1.9, and 1.2 false positives per image, and 5.5, 2.8, and 1.7 false positives per patient, respectively. The low performance of the conventional

  4. Tomosynthesis for the early detection of pulmonary emphysema: diagnostic performance compared with chest radiography, using multidetector computed tomography as reference.

    Science.gov (United States)

    Yamada, Yoshitake; Jinzaki, Masahiro; Hashimoto, Masahiro; Shiomi, Eisuke; Abe, Takayuki; Kuribayashi, Sachio; Ogawa, Kenji

    2013-08-01

    To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA-950) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. ROC analysis revealed significantly better performance (P pulmonary emphysema. The average sensitivity, specificity, positive predictive value and negative predictive value of tomosynthesis were 0.875, 0.968, 0.955 and 0.910, respectively, whereas the values for radiography were 0.479, 0.913, 0.815 and 0.697, respectively. For both tomosynthesis and radiography, the sensitivity increased with increasing LAA-950. The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA-950. • Tomosynthesis showed significantly better diagnostic performance for pulmonary emphysema than radiography. • Interobserver agreement for tomosynthesis was significantly higher than that for radiography. • Sensitivity increased with increasing LAA -950 in both tomosynthesis and radiography. • Tomosynthesis imparts a similar radiation dose to two projection chest radiography. • Radiation dose and cost of tomosynthesis are lower than those of MDCT.

  5. Image quality of a Konica Regius 336 digital system in chest radiography

    International Nuclear Information System (INIS)

    Ostinelli, A.; Frigerio, M.; Monti, A.F.; Gelosa, S.; Tognoli, P.; Perniola, N.; Gozzi, G.

    2000-01-01

    Digital radiographic systems permit to optimize execution, depiction and storage of radiological images. Since a Regius 336 digital system (Konica Corp. Tokyo, Japan) devoted to chest radiography Department of S. Anna Hospital in Como, Italy, it was investigated its performance relative to image quality. Konica Regius 336 is a computed radiography system made of a phosphorescence detector plate which is scanned with an infrared semiconductor laser beam. The radiographic image obtained from the detector is subjected to image processing, which allows a stable output and the nonlinear curve typical of conventional radiographic systems. Image quality was assessed based on the following parameters: dose, contrast, noise and spatial resolution. As reference, it was assessed the same parameters on a Cronex 88 analogic chest-changer (DuPont Pharma, North Billerica, Mass, USA). The Regius 336 air kerma values were always higher than the analogic ones (about 10%), both with and without a chest phantom; noise was also greater than in analogic images, sometimes even doubled. The optical densities of a step wedge and the spatial resolution of the digital chest-changer are independent of the X-ray tube voltage consequent to broader optical latitude. Inversely, the analogic images of the wedges show great optical density variability as a function of the X-ray tube voltage (in a range of 2). The modulation transfer functions of the two systems have the same trend. The performance of the Konica Regius 336 is nearly equivalent to that of an analogic system. The main advantages of the digital system are a standard output, lower consumption of radiographic films, higher productiveness and better image quality standard level [it

  6. Tomosynthesis for the early detection of pulmonary emphysema: diagnostic performance compared with chest radiography, using multidetector computed tomography as reference

    International Nuclear Information System (INIS)

    Yamada, Yoshitake; Jinzaki, Masahiro; Hashimoto, Masahiro; Shiomi, Eisuke; Kuribayashi, Sachio; Abe, Takayuki; Ogawa, Kenji

    2013-01-01

    To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA -950 ) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. ROC analysis revealed significantly better performance (P -950 . The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA -950 . (orig.)

  7. Low Yield of Chest Radiography in a Large Tuberculosis Screening Program1

    Science.gov (United States)

    Pollock, Nira R.

    2010-01-01

    Purpose: To assess the frequency and spectrum of abnormalities on routine screening chest radiographs in the pre-employment evaluation of health care workers with positive tuberculin skin test (TST) results. Materials and Methods: The institutional review board approved this HIPAA-compliant retrospective study and waived the need for written informed patient consent. Chest radiographic reports of all 2586 asymptomatic individuals with positive TST results who underwent pre-employment evaluation between January 1, 2003, and December 31, 2007, were evaluated to determine the frequency of detection of evidence of active tuberculosis (TB) or latent TB infection (LTBI) and the spectrum of imaging findings. All chest radiographs interpreted as positive were reviewed by an experienced board-certified radiologist. If there was a discrepancy between the two readings, a second experienced radiologist served as an independent and final arbiter. Any follow-up chest radiographs or computed tomographic images that had been acquired by employee health services or by the employee’s private physician as a result of a suspected abnormality detected at initial screening were also evaluated. Results: Of the 159 (6.1%) chest radiographic examinations that yielded abnormal results, there were no findings that were consistent with active TB. There were 92 cases of calcified granulomas, calcified lymph nodes, or both; 25 cases of apical pleural thickening; 16 cases of fibrous scarring; and 31 cases of noncalcified nodules. All cases of fibrous scarring involved an area smaller than 2 cm2. All noncalcified nodules were 4 mm in diameter or smaller, with the exception of one primary lung malignancy and one necrotizing granuloma (negative for acid-fast bacilli) that grew Mycobacterium kansasii on culture. Conclusion: Universal chest radiography in a large pre-employment TB screening program was of low yield in the detection of active TB or increased LTBI reactivation risk, and it provided

  8. No Value for Routine Chest Radiography in the Work-Up of Early Stage Cervical Cancer Patients

    Science.gov (United States)

    Hoogendam, Jacob P.; Zweemer, Ronald P.; Verkooijen, Helena M.; de Jong, Pim A.; van den Bosch, Maurice A. A. J.; Verheijen, René H. M.; Veldhuis, Wouter B.

    2015-01-01

    Aim Evidence supporting the recommendation to include chest radiography in the work-up of all cervical cancer patients is limited. We investigated the diagnostic value of routine chest radiography in cervical cancer staging. Methods All consecutive cervical cancer patients who presented at our tertiary referral center in the Netherlands (January 2006 – September 2013), and for whom ≥6 months follow-up was available, were included. As part of the staging procedure, patients underwent a routine two-directional digital chest radiograph. Findings were compared to a composite reference standard consisting of all imaging studies and histology obtained during the 6 months following radiography. Results Of the 402 women who presented with cervical cancer, 288 (71.6%) underwent chest radiography and had ≥6 months follow-up. Early clinical stage (I/II) cervical cancer was present in 244/288 (84.7%) women, while 44 (15.3%) presented with advanced disease (stage III/IV). The chest radiograph of 1 woman – with advanced pre-radiograph stage (IVA) disease – showed findings consistent with pulmonary metastases. Radiographs of 7 other women – 4 early, 3 advanced stage disease – were suspicious for pulmonary metastases which was confirmed by additional imaging in only 1 woman (with pre-radiograph advanced stage (IIIB) disease) and excluded in 6 cases, including all women with early stage disease. In none of the 288 women were thoracic skeletal metastases identified on imaging or during 6 months follow up. Radiography was unremarkable in 76.4% of the study population, and showed findings unrelated to the cervical carcinoma in 21.2%. Conclusion Routine chest radiography was of no value for any of the early stage cervical cancer patients presenting at our tertiary center over a period of 7.7 years. PMID:26135733

  9. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures.

    Science.gov (United States)

    Szucs-Farkas, Zsolt; Lautenschlager, Katrin; Flach, Patricia M; Ott, Daniel; Strautz, Tamara; Vock, Peter; Ruder, Thomas D

    2011-08-01

    To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p=0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p=0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, prib fractures. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  10. Diagnostic impact of digital tomosynthesis in oncologic patients with suspected pulmonary lesions on chest radiography.

    Science.gov (United States)

    Quaia, Emilio; Baratella, Elisa; Poillucci, Gabriele; Gennari, Antonio Giulio; Cova, Maria Assunta

    2016-08-01

    To assess the actual diagnostic impact of digital tomosynthesis (DTS) in oncologic patients with suspected pulmonary lesions on chest radiography (CXR). A total of 237 patients (135 male, 102 female; age, 70.8 ± 10.4 years) with a known primary malignancy and suspected pulmonary lesion(s) on CXR and who underwent DTS were retrospectively identified. Two radiologists (experience, 10 and 15 years) analysed in consensus CXR and DTS images and proposed a diagnosis according to a confidence score: 1 or 2 = definitely or probably benign pulmonary or extrapulmonary lesion, or pseudolesion; 3 = indeterminate; 4 or 5 = probably or definitely pulmonary lesion. DTS findings were proven by CT (n = 114 patients), CXR during follow-up (n = 105) or histology (n = 18). Final diagnoses included 77 pulmonary opacities, 26 pulmonary scars, 12 pleural lesions and 122 pulmonary pseudolesions. DTS vs CXR presented a higher (P chest radiography (CXR) in oncologic patients. • DTS improves confidence of CXR in oncologic patients. • DTS allowed avoidance of CT in about 50 % of oncologic patients.

  11. Comparison of sputum acid-fast culture and chest radiography in pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Lim, G.M.

    1991-01-01

    While it is still a common practice of some clinicians to rely on chest radiography examination alone for the diagnosis of pulmonary tuberculosis, others still claim that absolute diagnosis of tuberculosis can firmly be established by bacteriological examination from secretions or tissues of the infected host. This study will evaluate the relationship between radiographic findings (CXR) and the likelihood of finding tubercle bacilli on sputum acid-fast bacilli (AFB) culture in pulmonary tuberculosis at Lung Center of the Philippines. Of 41 individuals who submitted their sputum for AFB culture, tubercle bacilli in the sputum was shown in 25 (60%) of cases and no growth of tubercle bacilli in 16 (40%) of cases. Chest radiography reading revealed tuberculosis in 100% of cases, of which when classified further, 22 (54%) has fibrohazed or hazy infiltrates on their CXR, 7 (17%) has cavitations or interpreted as moderate or far advanced TB, 12 (29%) has fibroid, nodular infiltrates or densities. In patients radiologically diagnosed as PTB minimal, sputum culture revealed tubercle bacilli in 15 (57%) among moderate, far advanced tuberculosis, and 6 (50%) among those with inactive or old tuberculosis. Therefore, the probability of detecting tubercle bacilli in pulmonary tuberculosis is not greatly influenced by radiographic findings. (auth.). 11 refs.; 2 figs.; 2 tabs

  12. Coronary calcium visualization using dual energy chest radiography with sliding organ registration

    Science.gov (United States)

    Wen, Di; Nye, Katelyn; Zhou, Bo; Gilkeson, Robert C.; Wilson, David L.

    2016-03-01

    Coronary artery calcification (CAC) is the lead biomarker for atherosclerotic heart disease. We are developing a new technique to image CAC using ubiquitously ordered, low cost, low radiation dual energy (DE) chest radiography (using the two-shot GE Revolution XRd system). In this paper, we proposed a novel image processing method (CorCalDx) based on sliding organ registration to create a bone-image-like, coronary calcium image (CCI) that significantly reduces motion artifacts and improves CAC conspicuity. Experiments on images of a physical dynamic cardiac phantom showed that CorCalDx reduced 73% of the motion artifact area as compared to standard DE over a range of heart rates up to 90 bpm and varying x-ray radiation exposures. Residual motion artifact in the phantom CCI is greatly suppressed in gray level and area (0.88% of the heart area). In a Functional Measurement Test (FMT) with 20 clinical exams, image quality improvement of CorCalDx against standard DE (measured from -10 to +10) was significantly suggested (panatomy visibility (6.1+/-3.5). CorCalDx was always chosen best in every image tested. In preliminary assessments of 12 patients with 18 calcifications, 90% of motion artifact regions in standard DE results were removed in CorCalDx results, with 100% sensitivity of calcification detection, showing great potential of CorCalDx to improve CAC detection and grading in DE chest radiography.

  13. A comparison of digital tomosynthesis and chest radiography in evaluating airway lesions using computed tomography as a reference.

    Science.gov (United States)

    Choo, Ji Yung; Lee, Ki Yeol; Yu, Ami; Kim, Je-Hyeong; Lee, Seung Heon; Choi, Jung Won; Kang, Eun-Young; Oh, Yu Whan

    2016-09-01

    To compare the diagnostic performance of digital tomosynthesis (DTS) and chest radiography for detecting airway abnormalities, using computed tomography (CT) as a reference. We evaluated 161 data sets from 149 patients (91 with and 70 without airway abnormalities) who had undergone radiography, DTS, and CT to detect airway problems. Radiographs and DTS were evaluated to localize and score the severity of the airway abnormalities, and to score the image quality using CT as a reference. Receiver operating characteristics (ROC), McNemar's test, weighted kappa, and the paired t-test were used for statistical analysis. The sensitivity of DTS was higher (reader 1, 93.51 %; reader 2, 94.29 %) than chest radiography (68.83 %; 71.43 %) in detecting airway lesions. The diagnostic accuracy of DTS (90.91 %; 94.70 %) was also significantly better than that of radiography (78.03 %; 82.58 %, all p chest radiography (1.83, 2.74; p < 0.05) in the results of both readers. The inter-observer agreement with respect to DTS findings was moderate and superior when compared to radiography findings. DTS is a more accurate and sensitive modality than radiography for detecting airway lesions that are easily obscured by soft tissue structures in the mediastinum. • Digital tomosynthesis offers new diagnostic options for airway lesions. • Digital tomosynthesis is more sensitive and accurate than radiography for airway lesions. • Digital tomosynthesis shows better image quality than radiography. • Assessment of lesion severity, via tomosynthesis is comparable to computed tomography.

  14. Investigation of physical imaging properties in various digital radiography systems

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hoi Woun [Dept. of Radiological Science, Baekseok Culture University, Cheonan (Korea, Republic of); Min, Jung Hwan [Dept. of Radiological technology, Shingu University, Seongnam (Korea, Republic of); Yoon, Yong Su [Dept. of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Kyushu (Japan); Kim, Jung Min [Dept. of Health and Environmental Science, College of Health Science, Korea University, Seoul (Korea, Republic of)

    2017-09-15

    We aimed to evaluate the physical imaging properties in various digital radiography systems with charged coupled device (CCD), computed radiography (CR), and indirect flat panel detector (FPD). The imaging properties measured in this study were modulation transfer function (MTF) wiener spectrum (WS), and detective quantum efficiency (DQE) to compare the performance of each digital radiography system. The system response of CCD were in a linear relationship with exposure and that of CR and FPD were proportional to the logarithm of exposure. The MTF of both CR and FPD indicated a similar tendency but in case of CCD, it showed lower MTF than that of CR and FPD. FPD showed the lowest WS and also indicated the highest DQE among three systems. According to the results, digital radiography system with different type of image receptor had its own image characteristics. Therefore, it is important to know the physical imaging characteristics of the digital radiography system accurately to obtain proper image quality.

  15. Tomosynthesis for the early detection of pulmonary emphysema: diagnostic performance compared with chest radiography, using multidetector computed tomography as reference

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yoshitake [Keio University School of Medicine, Department of Diagnostic Radiology, Tokyo (Japan); Nippon Koukan Hospital, Department of Radiology, Kawasaki-shi, Kanagawa (Japan); Jinzaki, Masahiro; Hashimoto, Masahiro; Shiomi, Eisuke; Kuribayashi, Sachio [Keio University School of Medicine, Department of Diagnostic Radiology, Tokyo (Japan); Abe, Takayuki [Keio University School of Medicine, Center for Clinical Research, Tokyo (Japan); Ogawa, Kenji [Nippon Koukan Hospital, Department of Radiology, Kawasaki-shi, Kanagawa (Japan)

    2013-08-15

    To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA{sub -950}) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. ROC analysis revealed significantly better performance (P < 0.0001) of tomosynthesis than radiography for the detection of pulmonary emphysema. The average sensitivity, specificity, positive predictive value and negative predictive value of tomosynthesis were 0.875, 0.968, 0.955 and 0.910, respectively, whereas the values for radiography were 0.479, 0.913, 0.815 and 0.697, respectively. For both tomosynthesis and radiography, the sensitivity increased with increasing LAA{sub -950}. The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA{sub -950}. (orig.)

  16. Improvement of the clinical use of computed radiography for mobile chest imaging: Image quality and patient dose

    Science.gov (United States)

    Rill, Lynn Neitzey

    Chest radiography is technically difficult because of the wide variation of tissue attenuations in the chest and limitations of screen-film systems. Mobile chest radiography, performed bedside on hospital inpatients, presents additional difficulties due to geometrical and equipment limitations inherent to mobile x-ray procedures and the severity of illness in patients. Computed radiography (CR) offers a new approach for mobile chest radiography by utilizing a photostimulable phosphor. Photostimulable phosphors are more efficient in absorbing lower-energy x-rays than standard intensifying screens and overcome some image quality limitations of mobile chest imaging, particularly because of the inherent latitude. This study evaluated changes in imaging parameters for CR to take advantage of differences between CR and screen-film radiography. Two chest phantoms, made of acrylic and aluminum, simulated x-ray attenuation for average-sized and large- sized adult chests. The phantoms contained regions representing the lungs, heart and subdiaphragm. Acrylic and aluminum disks (1.9 cm diameter) were positioned in the chest regions to make signal-to-noise ratio (SNR) measurements for different combinations of imaging parameters. Disk thicknesses (contrast) were determined from disk visibility. Effective dose to the phantom was also measured for technique combinations. The results indicated that using an anti-scatter grid and lowering x- ray tube potential improved the SNR significantly; however, the dose to the phantom also increased. An evaluation was performed to examine the clinical applicability of the observed improvements in SNR. Parameter adjustments that improved phantom SNRs by more than 50% resulted in perceived image quality improvements in the lung region of clinical mobile chest radiographs. Parameters that produced smaller improvements in SNR had no apparent effect on clinical image quality. Based on this study, it is recommended that a 3:1 grid be used for

  17. Chest radiography for predicting the cause of febrile illness among inpatients in Moshi, Tanzania

    International Nuclear Information System (INIS)

    Fiorillo, S.P.; Diefenthal, H.C.; Goodman, P.C.; Ramadhani, H.O.; Njau, B.N.; Morrissey, A.B.; Maro, V.P.; Saganda, W.; Kinabo, G.D.; Mwako, M.S.; Bartlett, J.A.

    2013-01-01

    Aim: To describe chest radiographic abnormalities and assess their usefulness for predicting causes of fever in a resource-limited setting. Materials and methods: Febrile patients were enrolled in Moshi, Tanzania, and chest radiographs were evaluated by radiologists in Tanzania and the United States. Radiologists were blinded to the results of extensive laboratory evaluations to determine the cause of fever. Results: Of 870 febrile patients, 515 (59.2%) had a chest radiograph available; including 268 (66.5%) of the adolescents and adults, the remainder were infants and children. One hundred and nineteen (44.4%) adults and 51 (20.6%) children were human immunodeficiency virus (HIV)-infected. Among adults, radiographic abnormalities were present in 139 (51.9%), including 77 (28.7%) with homogeneous and heterogeneous lung opacities, 26 (9.7%) with lung nodules, 25 (9.3%) with pleural effusion, 23 (8.6%) with cardiomegaly, and 13 (4.9%) with lymphadenopathy. Among children, radiographic abnormalities were present in 87 (35.2%), including 76 (30.8%) with homogeneous and heterogeneous lung opacities and six (2.4%) with lymphadenopathy. Among adolescents and adults, the presence of opacities was predictive of Streptococcus pneumoniae and Coxiella burnetii, whereas the presence of pulmonary nodules was predictive of Histoplasma capsulatum and Cryptococcus neoformans. Conclusions: Chest radiograph abnormalities among febrile inpatients are common in northern Tanzania. Chest radiography is a useful adjunct for establishing an aetiologic diagnosis of febrile illness and may provide useful information for patient management, in particular for pneumococcal disease, Q fever, and fungal infections

  18. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures

    Energy Technology Data Exchange (ETDEWEB)

    Szucs-Farkas, Zsolt, E-mail: zsolt.szuecs@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Lautenschlager, Katrin, E-mail: katrin@students.unibe.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Flach, Patricia M., E-mail: patricia.flach@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ott, Daniel, E-mail: daniel.ott@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Strautz, Tamara, E-mail: tamara.strautz@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Vock, Peter, E-mail: peter.vock@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ruder, Thomas D., E-mail: thomas.ruder@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland)

    2011-08-15

    Objective: To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. Materials and methods: In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. Results: The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p = 0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p = 0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, p < 0.001). Conclusions: Despite a better image quality, adding ES bone images to standard radiographs of the chest does not provide better sensitivity or improved diagnostic confidence in the detection of rib fractures.

  19. Protocols and guidelines for mobile chest radiography in Irish public hospitals

    International Nuclear Information System (INIS)

    Kelly, Amanda; Toomey, Rachel

    2015-01-01

    Background: The mobile chest radiograph is a highly variable examination, in both technique and setting. Protocols and guidelines are one method by which examinations can be standardised, and provide information when one is unsure how to proceed. This study was undertaken to investigate the existence of protocols and guidelines available for the mobile chest radiograph, to establish their nature and compare them under a variety of headings. Methodology: A postal survey was administered to the Radiography Service Managers in the public hospitals under the governance of the Health Service Executive (HSE) in Ireland. The survey contained questions regarding hospital demographics, contents of existing protocols or guidelines, and why a protocol or guideline was not in place, if this was the case. Results: The response rate to the survey was 62% (n = 24). Those that had a specific protocol in place amounted to 63% (n = 15), 71% (n = 17) had a specific guideline, and 63% (n = 15) had both. Twenty nine percent (n = 7) had no specific protocol/guideline in place. Scientific research (88%, n = 15) and radiographer experience (82%, n = 14) were the most common sources used to inform protocols and guidelines. Conclusions: There are protocols and guidelines available to radiographers for mobile chest radiography in the majority of public hospitals in Ireland. The nature of the protocols and guidelines generally coincides with the HSE guidance regarding what sources of information should be used and how often they should be updated

  20. Effects of tube potential and scatter rejection on image quality and effective dose in digital chest X-ray examination: An anthropomorphic phantom study

    International Nuclear Information System (INIS)

    Shaw, D.J.; Crawshaw, I.; Rimmer, S.D.

    2013-01-01

    Objectives: The purpose of this study was to investigate the effects of tube potential and scatter rejection techniques on image quality of digital posteroanterior (PA) chest radiographs. Methods: An anthropomorphic phantom was imaged using a range of tube potentials (81–125 kV p ) without scatter rejection, with an anti-scatter grid, and using a 10 cm air gap. Images were anonymised and randomised before being evaluated using a visual graded analysis (VGA) method. Results: The effects of tube potential on image quality were found to be negligible (p > 0.63) for the flat panel detector (FPD). Decreased image quality (p = 0.031) was noted for 125 kV p relative to 109 kV p , though no difference was noted for any of the other potentials (p > 0.398) for computed radiography (CR). Both scatter rejection techniques improved image quality (p p . Scatter rejection improved image quality, but with no difference found between techniques. The air-gap resulted in a smaller increase in effective dose than the anti-scatter grid and would be the preferred scatter rejection technique

  1. Sonography of the chest using linear-array versus sector transducers: Correlation with auscultation, chest radiography, and computed tomography.

    Science.gov (United States)

    Tasci, Ozlem; Hatipoglu, Osman Nuri; Cagli, Bekir; Ermis, Veli

    2016-07-08

    The primary purpose of our study was to compare the efficacies of two sonographic (US) probes, a high-frequency linear-array probe and a lower-frequency phased-array sector probe in the diagnosis of basic thoracic pathologies. The secondary purpose was to compare the diagnostic performance of thoracic US with auscultation and chest radiography (CXR) using thoracic CT as a gold standard. In total, 55 consecutive patients scheduled for thoracic CT were enrolled in this prospective study. Four pathologic entities were evaluated: pneumothorax, pleural effusion, consolidation, and interstitial syndrome. A portable US scanner was used with a 5-10-MHz linear-array probe and a 1-5-MHz phased-array sector probe. The first probe used was chosen randomly. US, CXR, and auscultation results were compared with the CT results. The linear-array probe had the highest performance in the identification of pneumothorax (83% sensitivity, 100% specificity, and 99% diagnostic accuracy) and pleural effusion (100% sensitivity, 97% specificity, and 98% diagnostic accuracy); the sector probe had the highest performance in the identification of consolidation (89% sensitivity, 100% specificity, and 95% diagnostic accuracy) and interstitial syndrome (94% sensitivity, 93% specificity, and 94% diagnostic accuracy). For all pathologies, the performance of US was superior to those of CXR and auscultation. The linear probe is superior to the sector probe for identifying pleural pathologies, whereas the sector probe is superior to the linear probe for identifying parenchymal pathologies. Thoracic US has better diagnostic performance than CXR and auscultation for the diagnosis of common pathologic conditions of the chest. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:383-389, 2016. © 2016 Wiley Periodicals, Inc.

  2. Pleural ultrasonography versus chest radiography for the diagnosis of pneumothorax: review of the literature and meta-analysis.

    Science.gov (United States)

    Alrajab, Saadah; Youssef, Asser M; Akkus, Nuri I; Caldito, Gloria

    2013-09-23

    Ultrasonography is being increasingly utilized in acute care settings with expanding applications. Pneumothorax evaluation by ultrasonography is a fast, safe, easy and inexpensive alternative to chest radiographs. In this review, we provide a comprehensive analysis of the current literature comparing ultrasonography and chest radiography for the diagnosis of pneumothorax. We searched English-language articles in MEDLINE, EMBASE and Cochrane Library dealing with both ultrasonography and chest radiography for diagnosis of pneumothorax. In eligible studies that met strict inclusion criteria, we conducted a meta-analysis to evaluate the diagnostic accuracy of pleural ultrasonography in comparison with chest radiography for the diagnosis of pneumothorax. We reviewed 601 articles and selected 25 original research articles for detailed review. Only 13 articles met all of our inclusion criteria and were included in the final analysis. One study used lung sliding sign alone, 12 studies used lung sliding and comet tail signs, and 6 studies searched for lung point in addition to the other two signs. Ultrasonography had a pooled sensitivity of 78.6% (95% CI, 68.1 to 98.1) and a specificity of 98.4% (95% CI, 97.3 to 99.5). Chest radiography had a pooled sensitivity of 39.8% (95% CI, 29.4 to 50.3) and a specificity of 99.3% (95% CI, 98.4 to 100). Our meta-regression and subgroup analyses indicate that consecutive sampling of patients compared to convenience sampling provided higher sensitivity results for both ultrasonography and chest radiography. Consecutive versus nonconsecutive sampling and trauma versus nontrauma settings were significant sources of heterogeneity. In addition, subgroup analysis showed significant variations related to operator and type of probe used. Our study indicates that ultrasonography is more accurate than chest radiography for detection of pneumothorax. The results support the previous investigations in this field, add new valuable information

  3. Deep Learning at Chest Radiography: Automated Classification of Pulmonary Tuberculosis by Using Convolutional Neural Networks.

    Science.gov (United States)

    Lakhani, Paras; Sundaram, Baskaran

    2017-08-01

    Purpose To evaluate the efficacy of deep convolutional neural networks (DCNNs) for detecting tuberculosis (TB) on chest radiographs. Materials and Methods Four deidentified HIPAA-compliant datasets were used in this study that were exempted from review by the institutional review board, which consisted of 1007 posteroanterior chest radiographs. The datasets were split into training (68.0%), validation (17.1%), and test (14.9%). Two different DCNNs, AlexNet and GoogLeNet, were used to classify the images as having manifestations of pulmonary TB or as healthy. Both untrained and pretrained networks on ImageNet were used, and augmentation with multiple preprocessing techniques. Ensembles were performed on the best-performing algorithms. For cases where the classifiers were in disagreement, an independent board-certified cardiothoracic radiologist blindly interpreted the images to evaluate a potential radiologist-augmented workflow. Receiver operating characteristic curves and areas under the curve (AUCs) were used to assess model performance by using the DeLong method for statistical comparison of receiver operating characteristic curves. Results The best-performing classifier had an AUC of 0.99, which was an ensemble of the AlexNet and GoogLeNet DCNNs. The AUCs of the pretrained models were greater than that of the untrained models (P chest radiography with an AUC of 0.99. A radiologist-augmented approach for cases where there was disagreement among the classifiers further improved accuracy. © RSNA, 2017.

  4. Experiences with a new film-screen system in pediatric chest radiography

    International Nuclear Information System (INIS)

    Leenen, A.; Brandt, G.A.; Riebel, T.; Marciniak, H.

    1996-01-01

    Purpose: To compare the X-ray images made by the Kodak InSight Pediatric Imaging System (InSight P) with conventional film-screen systems in pediatric chest radiography. Material and methods: The comparison involved chest radiographs made using Quanta-Fast-Detail/Cronex 4 (DuPont), Trimax 16/XDA (3 M) and DuPont UVR/UVL systems. The image quality of critical structures and the physical parameters of quantum interference, contrast and resolution were assessed. The energy path of the system was assessed by preparing density curves. Test conditions were in accordance with the latest guidelines of the Bundesaerztekammer (German Physicians' Association). Results: The mediastinal area, retrocardiac and paravertebral spaces and the peripheral vessels of the lung were all displayed more distinctly using InSight P. The reason for this seems to be a lower degree of quantum interference associated with this system. With tube voltages between 60 and 80 kV, InSight P displayed a relatively low degree of sensitivity. Conclusion: InSight P can be used to produce predominantly high quality chest radiographs on infants between one and five years of age. However, this system has limited sensitivity in the tube voltage range recommended by the German Physicians' Association. (orig.) [de

  5. The cost-effectiveness of carbon-fibre cassettes in mobile chest radiography

    International Nuclear Information System (INIS)

    Brennan, P.C.; Hourihan, S.P.

    1998-01-01

    Employment of carbon fibre materials is an effective method of reducing radiation dose, yet the increased associated costs have led to a reluctance in implementation. This study investigates the level of dose reduction achievable, while maintaining image quality, in mobile chest radiography using carbon-fibre cassettes, compared with plastic cassettes, and balances this against increased expense of the cassettes. Dose measurements using thermoluminescent dosimeters were carried out on intensive therapy unit (ITU) patients undergoing an anteroposterior chest X-ray examination. Resultant image quality was assessed using objective Commission of European Communities (CEC) criteria. A retrospective audit recorded number of ITU patients currently having chest X-rays to determine total dose savings over the life of the cassettes. The results show significant reductions (p < 0.0001) of 32 % for entrance surface and effective dose with carbon-fibre cassettes. No deterioration in total image quality was noted. The added expense of ≤ 2260 per personSievert (calculated from the effective dose reduction) for employing carbon-fibre cassettes is minimal compared with the estimated cost of manSievert exposures reported by other workers. (orig.)

  6. Screening for lung cancer with digital chest radiography: sensitivity and number of secondary work-up CT examinations

    NARCIS (Netherlands)

    de Hoop, Bartjan; Schaefer-Prokop, Cornelia; Gietema, Hester A.; de Jong, Pim A.; van Ginneken, Bram; van Klaveren, Rob J.; Prokop, Mathias

    2010-01-01

    To estimate the performance of digital chest radiography for detection of lung cancer. The study had ethics committee approval, and a nested case-control design was used and included 55 patients with lung cancer detected at computed tomography (CT) and confirmed with histologic examination and a

  7. Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

    International Nuclear Information System (INIS)

    Zhang, Yakun; Li, Xiang; Segars, W. Paul; Samei, Ehsan

    2014-01-01

    Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI vol and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose metrics

  8. Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yakun [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Li, Xiang [Medical Physics Graduate Program, Department of Physics, Cleveland State University, Cleveland, Ohio 44115 (United States); Segars, W. Paul [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Samei, Ehsan, E-mail: samei@duke.edu [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Departments of Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States)

    2014-02-15

    Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI{sub vol} and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose

  9. The clinical significance of Fuji computed radiography on lateral chest radiogram

    International Nuclear Information System (INIS)

    Kifune, Kouichi

    1995-01-01

    The purpose of this study was to clarify the benefits of digital lateral chest radiogram. In the basic study, the modulation transfer factor (MTF) and the wiener spectra (WS) of conventional screen film (CSF) and Fuji computed radiography (FCR) were measured. The visibility of the simulated nodules on FCR using 3 human bodies was subjectively compared with that on CSF by 13 observers. In the clinical study, the visibility of the normal structures on FCR was subjectively compared with that on CSF using 50 lateral chest radiograms by 10 observers. The diagnostic performance to detect pulmonary nodules on FCR was also compared with that on CSF using each 30 positive and negative cases by 8 observers. In the basic study, the MTF of FCR was superior to that of CSF, and the WS of FCR displayed in half size was superior to that of CSF. In all exposure conditions, the visibility of the nodules on FCR in the pulmonary apex was inferior to that on CSF, while FCR was superior to CSF in the other lung field. However, the visibility of the nodules on FCR in the pulmonary apex was improved when the exposure condition was increased. In the clinical study, the visibility of the normal structures on FCR was comparable or superior to that on CSF except for interlobar fissure due to resolution properties. The diagnostic performance of pulmonary nodules on FCR was comparable to that on CSF especially in classifying the marginal character and diameter of the nodules. According to the location of the nodules, the detectability of FCR was superior to that of CSF in the retrosternal space and tended to be inferior to that of CSF in the pulmonary apex. An adequate exposure condition should be considered before discussing the visibility and detectability of abnormal shadow in the lateral chest radiogram. In conclusion, the digital lateral chest radiogram is superior to the CSF images, mainly because of wide latitude in FCR. (author)

  10. TU-CD-BRA-11: Application of Bone Suppression Technique to Inspiratory/expiratory Chest Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, R; Sanada, S [Kanazawa University, Kanazawa, Ishikawa (Japan); Sakuta, K; Kawashima, H [Kanazawa University Hospital, Kanazawa, Ishikawa (Japan); Kishitani, Y [TOYO Corporation, Chuoh-ku, Tokyo (Japan)

    2015-06-15

    Purpose: The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images normally obtained by the dual-energy subtraction technique. This study was performed to investigate the usefulness of bone suppression technique in quantitative analysis of pulmonary function in inspiratory/expiratory chest radiography. Methods: Commercial bone suppression image processing software (ClearRead; Riverain Technologies) was applied to paired inspiratory/expiratory chest radiographs of 107 patients (normal, 33; abnormal, 74) to create corresponding bone suppression images. The abnormal subjects had been diagnosed with pulmonary diseases, such as pneumothorax, pneumonia, emphysema, asthma, and lung cancer. After recognition of the lung area, the vectors of respiratory displacement were measured in all local lung areas using a cross-correlation technique. The measured displacement in each area was visualized as displacement color maps. The distribution pattern of respiratory displacement was assessed by comparison with the findings of lung scintigraphy. Results: Respiratory displacement of pulmonary markings (soft tissues) was able to be quantified separately from the rib movements on bone suppression images. The resulting displacement map showed a left-right symmetric distribution increasing from the lung apex to the bottom region of the lung in many cases. However, patients with ventilatory impairments showed a nonuniform distribution caused by decreased displacement of pulmonary markings, which were confirmed to correspond to area with ventilatory impairments found on the lung scintigrams. Conclusion: The bone suppression technique was useful for quantitative analysis of respiratory displacement of pulmonary markings without any interruption of the rib shadows. Abnormal areas could be detected as decreased displacement of pulmonary markings. Inspiratory/expiratory chest radiography combined

  11. Compton radiography, 3. Compton scinti-tomography of the chest diseases

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, S; Sera, K; Shishido, F; Fukuda, H [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer; Mishina, H

    1977-10-01

    The compton radiography aims at collection of depth information by recording with a scinticamera those Compton rays that have resulted from scattering of a monoenergetic gamma beam by a volume of interest. Appreciably clear clinical scinti-tomograms were obtained of the chest wall, and intrathoracic structures such as the lungs, intrapulmonary pathologies, and mediastinum. This was achieved without any computer assistance for image reconstruction such as those in the case of XCT. Apparently, suitable corrections of the attenuations of the primary monoenergetic gamma rays and secondary Compton rays would greatly improve the image quality, and imaging time and radiation exposure as well. This technic is simple in principle, relatively cheap, and yet prospective of development of stereoptic fluoroscopy that would be extremely helpful in guiding such procedures as visceral biopsies.

  12. Optimization of digital chest radiography using computer modeling and voxels phantoms

    International Nuclear Information System (INIS)

    Correa, S.C.A.; Souza, E.M.; Silva, A.X.; Lopes, R.T.

    2009-01-01

    The purpose of this work is to use the Monte Carlo code MCNPX and the Female Adult voxel (FAX) and Male Adult voxel (MAX) phantoms to investigate how the dose and image quality in digital chest radiography vary with tube voltage (70-150 kV), anti-scatter methods (grid and air gap) and gender of the patient. The effective dose was calculated by ICRP60 and image quality was quantified by calculating the signal-difference-to-noise ratio for pathological details (calcifications) positioned at different locations in the anatomy. Calculated quantities were normalized to a fixed value of air kerma (5 μGy) at the automatic exposure control chambers. The results obtained in this work show that the air gap technique and lower tube voltages provide an increase in the digital image quality. Furthermore, this study has also shown that the detection of pathological details vary with the gender of the patient. (author)

  13. [Development of image quality assurance support system using image recognition technology in radiography in lacked images of chest and abdomen].

    Science.gov (United States)

    Shibuya, Toru; Kato, Kyouichi; Eshima, Hidekazu; Sumi, Shinichirou; Kubo, Tadashi; Ishida, Hideki; Nakazawa, Yasuo

    2012-01-01

    In order to provide a precise radiography for diagnosis, it is required that we avoid radiography with defects by having enough evaluation. Conventionally, evaluation was performed only by observation of a radiological technologist (RT). The evaluation support system was developed for providing a high quality assurance without depending on RT observation only. The evaluation support system, called as the Image Quality Assurance Support System (IQASS), is characterized in that "image recognition technology" for the purpose of diagnostic radiography of chest and abdomen areas. The technique of the system used in this study. Of the 259 samples of posterior-anterior (AP) chest, lateral chest, and upright abdominal x-rays, the sensitivity and specificity was 93.1% and 91.8% in the chest AP, 93.3% and 93.6% in the chest lateral, and 95.0% and 93.8% in the upright abdominal x-rays. In the light of these results, it is suggested that AIQAS could be applied to practical usage for the RT.

  14. Initial quality performance results using a phantom to simulate chest computed radiography

    Directory of Open Access Journals (Sweden)

    Muhogora Wilbroad

    2011-01-01

    Full Text Available The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR. The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm, 10 mm x 10 mm x 0.5 mm and 10 mm x 10 mm x 1 mm copper plates, respectively. A test object of 100 mm x 100 mm and 0.2 mm thick copper was positioned to each region for CNR measurements. The phantom was exposed to x-rays generated by different tube potentials that covered settings in clinical use: 110-120 kVp (HVL=4.26-4.66 mm Al at a source image distance (SID of 180 cm. An approach similar to the recommended method in digital mammography was applied to determine the CNR values of phantom images produced by a Kodak CR 850A system with post-processing turned off. Subjective contrast-detail studies were also carried out by using images of Leeds TOR CDR test object acquired under similar exposure conditions as during CNR measurements. For clinical kVp conditions relevant to chest radiography, the CNR was highest over 90-100 kVp range. The CNR data correlated with the results of contrast detail observations. The values of clinical tube potentials at which CNR is the highest are regarded to be optimal kVp settings. The simplicity in phantom construction can offer easy implementation of related quality control program.

  15. Localized Energy-Based Normalization of Medical Images: Application to Chest Radiography.

    Science.gov (United States)

    Philipsen, R H H M; Maduskar, P; Hogeweg, L; Melendez, J; Sánchez, C I; van Ginneken, B

    2015-09-01

    Automated quantitative analysis systems for medical images often lack the capability to successfully process images from multiple sources. Normalization of such images prior to further analysis is a possible solution to this limitation. This work presents a general method to normalize medical images and thoroughly investigates its effectiveness for chest radiography (CXR). The method starts with an energy decomposition of the image in different bands. Next, each band's localized energy is scaled to a reference value and the image is reconstructed. We investigate iterative and local application of this technique. The normalization is applied iteratively to the lung fields on six datasets from different sources, each comprising 50 normal CXRs and 50 abnormal CXRs. The method is evaluated in three supervised computer-aided detection tasks related to CXR analysis and compared to two reference normalization methods. In the first task, automatic lung segmentation, the average Jaccard overlap significantly increased from 0.72±0.30 and 0.87±0.11 for both reference methods to with normalization. The second experiment was aimed at segmentation of the clavicles. The reference methods had an average Jaccard index of 0.57±0.26 and 0.53±0.26; with normalization this significantly increased to . The third experiment was detection of tuberculosis related abnormalities in the lung fields. The average area under the Receiver Operating Curve increased significantly from 0.72±0.14 and 0.79±0.06 using the reference methods to with normalization. We conclude that the normalization can be successfully applied in chest radiography and makes supervised systems more generally applicable to data from different sources.

  16. A Clinical Study on a 5 Decades Tuberculosis Screening Program Based on Chest Radiography(CXR)

    International Nuclear Information System (INIS)

    Kim, Ham Gyun

    2009-01-01

    This study analyzed decade-based statistic data which had been collected from the reports of annual radiographic pulmonary tuberculosis screening program initiated by the Korean National Tuberculosis Association (KNTA) for last 5 decades (from 1956 to 2005). We analyzed only the content of annual statistic report to preserve the characteristic of statistic data and the contents of original copy by focusing on the analysis of tuberculosis cases where age and sex were excluded. The results of the disease-based analysis on the tuberculosis cases from cumulative subjects of chest radiography (CXR) from 1956 to 2005 are summarized as follows. 1. The cumulative number of subjects who were examined under annual chest radiography over last 5 decades totaled 54,938,875 persons. 2. The cumulative number of pulmonary tuberculosis cases during same period totaled 958,251 persons (1.74%). 3. The cumulative number of subjects treated during same period totaled 465,082 persons (0.85%). 4. The cumulative number of mild pulmonary tuberculosis cases during same period totaled 229,615 persons (0.42%). 5. The cumulative number of moderate pulmonary tuberculosis cases during same period totaled 144,247 persons (0.26%). 6. The cumulative number of severe pulmonary tuberculosis cases during same period totaled 74,066 persons (0.13%). 7. The cumulative number of exudative pleurisy cases during same period totaled 17,154 persons (0.03%). 8. The cumulative number of subjects under monitoring during same period totaled 493,169 persons (0.90%). 9. The cumulative number of uncertain activity cases during same period totaled 78,214 persons (0.14%). 10. The cumulative number of pseudo-pulmonary tuberculosis cases during same period totaled 272,349 persons (0.50%).

  17. Constancy tests radiography X-ray devices with CR system

    International Nuclear Information System (INIS)

    Durdikova, M.; Zakova, M.

    2005-01-01

    The paper presents the changes in QAP (Quality Assurance Program) as consequence of digitalisation of medical facilities. Digitalisation brings many advantages - more comfort for personal use, images are easy achievable and transferable to workstation, fine quality images by postprocessing are easily achievable. But it must be taken into account that due to simplicity of image make it is sometimes taken more images then necessary .There are two possible ways of digitalisation in radiography: to exchange conventional developer machine by Computer Radiography (CR), that means to use CR reader and cassette with phosphor plate - un-direct digitalisation or to use special radiography X-ray devices with flat-panel detector -direct radiography. (authors)

  18. Possibility of clinical usefulness of heavy metal filter combinations in digital chest radiography

    International Nuclear Information System (INIS)

    Kawaji, Yasuyuki; Ideguchi, Tadamitsu; Ikeda, Hirotaka; Sakamoto, Hiromi; Higashida, Yoshiharu; Toyofuku, Fukai

    2003-01-01

    We have investigated the potential usefulness of the heavy metal filters with higher atomic numbers by comparing their patient exposures, tube loadings, radiographic contrasts, and the visual detection of simulated nodules in computed radiography (CR) with those of a combination of copper and aluminum. Seven heavy metal filters were used for this study. As for a tungsten filter, two filters different in thickness were used. One is 0.05 mm thick, and the other 0.10 mm. The other metal filters were respectively combined with a tungsten filter with a thickness of 0.05 mm. Among the all filters, tungsten with 0.1 mm thick and tungsten with 0.05 mm+barium which showed larger advantages in patient exposure and tube loading than those of the other filters were used for detection task of simulated nodules in chest radiography. The results indicated that the use of heavy metal filters can improve detectability of simulated nodules over that obtainable with conventional copper and aluminum filter. (author)

  19. A study on the distribution of scatter ray in chest radiography of a health examination bus

    International Nuclear Information System (INIS)

    Cho, Ji Hwan; Jin, Seong Jin; Min, Byeong In

    2017-01-01

    The purpose of this study was to evaluate the distribution of spatial scatter ray on the chest radiographs of patients on health examination bus. In this paper, we propose a method for minimize unnecessary exposure by measuring the scattered dose after exposure the actual subject and comparing the body mass index (BMI) with the tube current amount mAs. The results of this study showed that the mean BMI of the subjects was 23.31±3.12. The mean mAs value was 2.92±1.19, which males was higher than females. The mean value of the scatter ray at position 1 in the radiography room was 771.81±151.15 μ/hr. The mean value of the scatter rays at the position 2 outside the entrance of the radiography room was measured as 53.86±25.66 μ/hr. As the BMI and mAs was increase the spatial scatter dose was increased at position 1 and position 2 in the photographing room. In order to minimize the exposure dose of scatter ray, radiation workers should shoot the radiation as low as possible within the range that does not impair the quality of the image. It will be necessary to make efforts to not wait for a waiting person near the entrance door of the photographing room

  20. Preliminary clinical evaluation of hard- and soft-copy digitized chest radiography

    Science.gov (United States)

    Rian, Roger L.; Smerud, Michael J.; Guinn, Todd

    1994-05-01

    The digital applications in radiology are a controversial advanced which potentially will influence all areas of patient imaging. It is utilized and accepted in angiography, computed tomography, magnetic resonance, nuclear imaging and sonography. More recently Computed Radiography has gained credibility in mobile scenarios as well as specific applications from cervical spine radiography to digital fluoroscopy. Usually this acceptance is related to benefits of lesser radiation exposure or an improved presentation with an incorrect radiographic technique. One advantage of interpreting from digital information is the potential manipulation of the image presentation to the observer through windowing, leveling and edge enhancement pre and/or during image review. Additionally this digital data can be transmitted over distance and represented as hard and/or soft copy for primary or consultative review. The number and quality of the images to be viewed, the environment of the review station as well as the observer experience with conventional radiographic as well as digital image evaluation are important aspects of delivering the radiologist's product i.e. the final interpretation. This paper assesses that product, specifically addressing the question `Is the radiologist's report the same whether derived from the original analog image or from its digitized image.' The object of this study is to determine whether a digital system (3M PACS) designed for consultative viewing in a satellite department can also be used directly for primary diagnosis of conventional chest exams.

  1. A study on the distribution of scatter ray in chest radiography of a health examination bus

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Ji Hwan [Dept. of Health Care Clinic, Inje University Busan Paik Hospital, Busan (Korea, Republic of); Jin, Seong Jin [Gammaknife center, Inje University Haeundae Paik Hospital, Busan (Korea, Republic of); Min, Byeong In [Dept. of of Nuclear Applied Engineering, Inje University, Incheon (Korea, Republic of)

    2017-09-15

    The purpose of this study was to evaluate the distribution of spatial scatter ray on the chest radiographs of patients on health examination bus. In this paper, we propose a method for minimize unnecessary exposure by measuring the scattered dose after exposure the actual subject and comparing the body mass index (BMI) with the tube current amount mAs. The results of this study showed that the mean BMI of the subjects was 23.31±3.12. The mean mAs value was 2.92±1.19, which males was higher than females. The mean value of the scatter ray at position 1 in the radiography room was 771.81±151.15 μ/hr. The mean value of the scatter rays at the position 2 outside the entrance of the radiography room was measured as 53.86±25.66 μ/hr. As the BMI and mAs was increase the spatial scatter dose was increased at position 1 and position 2 in the photographing room. In order to minimize the exposure dose of scatter ray, radiation workers should shoot the radiation as low as possible within the range that does not impair the quality of the image. It will be necessary to make efforts to not wait for a waiting person near the entrance door of the photographing room.

  2. The study on the image quality and patient exposure dose of chest radiography in Korea

    International Nuclear Information System (INIS)

    Lee, Sun Sook; Huh, Joon

    1995-01-01

    Recently, general radiography became to variety because of the continuous development of Inverter type generator and ortho chromatic system. Therefore, we must re-evaluate about patient exposure dose and image quality. I studied about chest radiography which has frequency among general radiography being used during FEB. to AUG., 1994 over 151 medical facilities from medical facilities that are located in Seoul area. The result obtained were as follows; 1) The rectification method of the generator were employing mainly single phase full wave in 82.8 %, three phase full wave in 11.26 % and Inverter type in 4.64 % and condenser type is 1.32 %. 2) Exposure kV was used below 80 kV in most medical facilities and 21.8 % of the medical facilities was using high tube voltage higher than 120 kV. 3) The exposure time was used below the 0.05 sec in 28.4 %, in 29.8 % of the medical facilities used above 0.1 sec. 4) The usage frequency of the added filter is 15.3 %, and among them compound filter was used only 4 %. 5) Rare earth screen was used in 37.7 %. 6) The average skin entrance dose was 0.25 mSv, the range of dose is 0.05∼0.79 mSv in each medical facilities. 7) The average density of the lung field is 1.76, 0.49 in lung side, 0.30 in mediastinum and 0.37 in heart shadow. Therefore it is required to improve all of these for increasing image quality and reducing patient exposure dose as soon as possible

  3. Large hiatal hernia at chest radiography in a woman with cardiorespiratory symptoms.

    Science.gov (United States)

    Torres, Daniele; Parrinello, Gaspare; Cardillo, Mauro; Pomilla, Marina; Trapanese, Caterina; Michele, Bellanca; Lupo, Umberto; Schimmenti, Caterina; Cuttitta, Francesco; Pietrantoni, Rossella; Vogiatzis, Danai; Licata, Giuseppe

    2012-11-01

    Hiatal hernia (HH) is a frequent entity. Rarely, it may exert a wide spectrum of clinical presentations mimicking acute cardiovascular events such as angina-like chest pain until manifestations of cardiac compression that can include postprandial syncope, exercise intolerance, respiratory function, recurrent acute heart failure, and hemodynamic collapse. A 69-year-old woman presented to the emergency department complaining of fatigue on exertion, cough, and episodes of restrosternal pain with less than 1 hour of duration. Her medical history only included some episodes of bronchitis and no history of hypertension. The 12-lead electrocardiogram demonstrated sinus rhythm with right bundle-branch block. Laboratory tests, including cardiac troponin I, were within normal reference values. Chest radiography showed no significant pulmonary alterations and revealed in mediastinum a huge abnormal shadow overlapping the right heart compatible with a gastric bubble.The gastroscopy confirmed a large HH. A 2-dimensional transthoracic echocardiogram, using all standard and modified apical and parasternal views, revealed an echolucent mass, compatible with HH, compressing the right atrium. Also, it showed an altered left ventricular relaxation and a mild increase of pulmonary artery pressure (35 mm Hg). Spirometry showed a mild obstruction of the small airways, whereas coronary angiography showed normal coronary arteries. We concluded that the patient's symptomatology was related to the compressive effects of the large hiatal ernia, a neglected cause of cardiorespiratory symptoms. The surgical repair of HH was indicated.

  4. Automatic method for selective enhancement of different tissue densities at digital chest radiography

    International Nuclear Information System (INIS)

    McNitt-Gray, M.F.; Taira, R.K.; Eldredge, S.L.; Razavi, M.

    1991-01-01

    This paper reports that digital chest radiographs often are too bright and/or lack contrast when viewed on a video display. The authors have developed a method that can automatically provide a series of look-up tables that selectively enhance the radiographically soft or dense tissues on a digital chest radiograph. This reduces viewer interaction and improves displayed image quality. On the basis of a histogram analysis, gray-level ranges are approximated for the patient background, radiographically soft tissues, and radiographically dense tissues. A series of look-up tables is automatically created by varying the contrast in each range to achieve a level of enhancement for a selected tissue range. This is repeated for differing amounts of enhancement and for each tissue range. This allows the viewer to interactively select a tissue density range and degree of enhancement at the time of display via precalculated look-up tables. Preclinical trials in pediatric radiology using computed radiography images show that this method reduces viewer interaction and improves or maintains the displayed image quality

  5. Pneumothorax and the Value of Chest Radiography after Ultrasound-Guided Thoracocentesis

    International Nuclear Information System (INIS)

    Pihlajamaa, K.; Bode, M.K.; Puumalainen, T.; Lehtimaeki, A.; Marjelund, S.; Tikkakoski, T.

    2004-01-01

    Purpose: To determine the incidence, the operator's experience, and other variables that may influence the development of pneumothorax or re-expansion edema after ultrasound (US)-guided thoracocentesis. Material and Methods: The medical records of 264 procedures in 212 patients who had undergone US-guided thoracocentesis in our radiology department or intensive care unit during the period 1996-2001 were retrospectively reviewed. Results: Post-thoracocentesis pneumothorax occurred in 11 cases, the incidence being 4.2% (11/264). None of the pneumothoraces occurred in the 10 mechanically ventilated patients. All but one patient with pneumothorax were asymptomatic or had only minor symptoms. Chest tube drainage was needed in one patient with a large pneumothorax. No re-expansion edema was recorded, although 1500 ml or more pleural fluid was aspirated in 29 patients. The operator's experience had no effect on the complication rate. Needle size was the only significant variable that contributed to the pneumothorax rate. Conclusion: US-guided thoracocentesis can be done equally as safely by residents as by senior radiologists. The safety and feasibility of the method are evident among mechanically ventilated intensive care patients. Our results do not support the routine use of post-thoracocentesis chest radiography

  6. High-resolution computed tomography versus chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis

    International Nuclear Information System (INIS)

    Azevedo, Ana Beatriz Cordeiro de; Calderaro, Debora; Moreira, Caio; Guimaraes, Silvana Mangeon Meirelles; Tavares Junior, Wilson Campos; Leao Filho, Hilton Muniz; Andrade, Diego Correa de; Ferreira, Cid Sergio; Vieira, Jose Nelson Mendes

    2005-01-01

    Objective: To compare the accuracy of high-resolution computed tomography (HRCT) with chest radiography in the diagnosis of interstitial lung disease in systemic sclerosis (SSc). Materials And Methods: HRCT scans and chest radiographs in postero-anterior and lateral views were performed in 34 patients with systemic sclerosis, according to the American College of Rheumatology preliminary criteria for the diagnosis of SSc. The prevalence of radiological findings suggestive of interstitial lung disease in SSc seen on both imaging methods was compared. Results: Interstitial disease was observed on HRCT images of 31 patients (91%) and in the chest radiographs of 16 patients (47%). The most frequent findings observed on HRCT were septal lines (74%), honeycombing (56%) and parenchymal bands (26%). Chest radiographs showed reticular areas of attenuation in 11 patients (32%) and parenchymal distortion in 12% of the patients. In 18 patients (53%) with normal chest radiographs HRCT showed septal lines in 55%, ground glass in 44%, honeycombing in 38.5% and cysts in 33%. Conclusion: HRCT is more sensitive than chest radiography in the evaluation of incipient interstitial lung involvement in patients with SSc and can provide a justification for immunosuppressive therapy in patients with early disease. (author)

  7. Effect of automatic exposure control marker with chest radiography in radiation reduction

    International Nuclear Information System (INIS)

    Jung, Ji Sang; Choi, Byoung Wook; Shim, Ji Na; Ahn, Ho Sik; Jin, Duk Eun; Liml, Jae Sik; Kang, Sung Ho; Kim, Sung Ho; Kim, Young Mo

    2014-01-01

    This study focused on effects of patient exposure dose reduction with AEC (Auto Exposure Control) marker that is designed for showing location of AEC in X-ray Chest radiography. It included 880 adults who have to use Chest X-ray Digital Radiography system (DRS, LISTEM, Korea). AEC (Ion chambers are posited in top of both sides) are used to every adult and set X-ray system as Field size 17 x 17 inch, 120 kVp, FFD 180 cm. 440 people of control group are posited on detector to include both sides of lung field and the other 440 people of experimental group are set to contact their lung directly to Ion chamber (making marker to shows location). Then, measured every DAP and, estimated patient effective dose by using PCXMC 2.0. The average age of control group (M:F=245:195) is 53.9 and the average BMI is 23.4. BMI ranges from under weight: 35, normal range: 279, over weight: 106 to obese: 20 and average DAP is 223.56 mGycm2, Mean effective dose is 0.045 mSv. The average age of experimental group (M:F=197:243) is 53.7 and the average BMI is 22.7. BMI ranges from under weight: 34, normal range: 315, over weight: 85 to obese: 6 and average DAP is 207.36 mGycm2, Mean effective dose is 0.041 mSv. Experimental group shows less Mean effective dose as 0.004mSv (9.7%) than control group. Also, patient numbers who got over exposure more than 0.056 mSv (limit point to know efficiency of AEC marker) is 65 in control group(14.7%), 19 in experimental group (4.3%) and take statistics with t-Test. The statistical difference between two groups is 0.006. In order to use proper amount of X-ray in auto exposure controlled chest X-ray system, matching location between ion chamber and body part is needed, and using AEC marker (designed for showing location of ion chamber) is a way to reduce unnecessary patient exposure dose

  8. Effect of automatic exposure control marker with chest radiography in radiation reduction

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ji Sang; Choi, Byoung Wook; Shim, Ji Na; Ahn, Ho Sik; Jin, Duk Eun; Liml, Jae Sik; Kang, Sung Ho [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Sung Ho [LISTEM, Woonju (Korea, Republic of); Kim, Young Mo [Dept. of Biomedical Engineering, Konyang University, Nonsan (Korea, Republic of)

    2014-09-15

    This study focused on effects of patient exposure dose reduction with AEC (Auto Exposure Control) marker that is designed for showing location of AEC in X-ray Chest radiography. It included 880 adults who have to use Chest X-ray Digital Radiography system (DRS, LISTEM, Korea). AEC (Ion chambers are posited in top of both sides) are used to every adult and set X-ray system as Field size 17 x 17 inch, 120 kVp, FFD 180 cm. 440 people of control group are posited on detector to include both sides of lung field and the other 440 people of experimental group are set to contact their lung directly to Ion chamber (making marker to shows location). Then, measured every DAP and, estimated patient effective dose by using PCXMC 2.0. The average age of control group (M:F=245:195) is 53.9 and the average BMI is 23.4. BMI ranges from under weight: 35, normal range: 279, over weight: 106 to obese: 20 and average DAP is 223.56 mGycm2, Mean effective dose is 0.045 mSv. The average age of experimental group (M:F=197:243) is 53.7 and the average BMI is 22.7. BMI ranges from under weight: 34, normal range: 315, over weight: 85 to obese: 6 and average DAP is 207.36 mGycm2, Mean effective dose is 0.041 mSv. Experimental group shows less Mean effective dose as 0.004mSv (9.7%) than control group. Also, patient numbers who got over exposure more than 0.056 mSv (limit point to know efficiency of AEC marker) is 65 in control group(14.7%), 19 in experimental group (4.3%) and take statistics with t-Test. The statistical difference between two groups is 0.006. In order to use proper amount of X-ray in auto exposure controlled chest X-ray system, matching location between ion chamber and body part is needed, and using AEC marker (designed for showing location of ion chamber) is a way to reduce unnecessary patient exposure dose.

  9. Effect of External Quality Assurance Evaluation for Chest Radiography: 3-Year Follow-Up in the Medical Institution for Pneumoconiosis

    International Nuclear Information System (INIS)

    Lee, Won Jeong; Choi, Soon Byung

    2012-01-01

    The aim of this study was to determine the effect of external quality assurance (QA) evaluation for chest radiography in the medical institution for pneumoconiosis (MIP). The chest radiography of the MIPs were evaluated for a radiological technique (RT), image quality (IQ), and reading environment (RE), during a 3-year follow up according to the Korean guidelines. Same methods were implemented each year to ensure that the results are reliable. RT, IQ, and RE were compared between examination and medical care (EMP), and only medical care (MCP) for pneumoconiosis, film-screen (FSR) and digital (DR) radiography. Uneducated and educated for QA during a 3-year follow up referencing with 2008 were realized. RT and IQ of the MIPs showed a significantly higher score in 2009 and 2010 compared with 2008 (p < 0.01). However, RE was not significantly improved. The score of RT, IQ, and RE of the EMPs were higher than those of MCPs every year, and FSR showed a lower score in all evaluations, although, more improvement was seen than the DR. The chest radiography of the MIPs showed a significant effect as a result of a repeated external QA evaluation. However, the MIPs need to transfer from FSR to DR, and maintain a continuous QA evaluation for the MCPs.

  10. Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages

    International Nuclear Information System (INIS)

    Sandborg, Michael; Tingberg, Anders; Ullman, Gustaf; Dance, David R.; Alm Carlsson, Gudrun

    2006-01-01

    The aim of this work was to study the dependence of image quality in digital chest and pelvis radiography on tube voltage, and to explore correlations between clinical and physical measures of image quality. The effect on image quality of tube voltage in these two examinations was assessed using two methods. The first method relies on radiologists' observations of images of an anthropomorphic phantom, and the second method was based on computer modeling of the imaging system using an anthropomorphic voxel phantom. The tube voltage was varied within a broad range (50-150 kV), including those values typically used with screen-film radiography. The tube charge was altered so that the same effective dose was achieved for each projection. Two x-ray units were employed using a computed radiography (CR) image detector with standard tube filtration and antiscatter device. Clinical image quality was assessed by a group of radiologists using a visual grading analysis (VGA) technique based on the revised CEC image criteria. Physical image quality was derived from a Monte Carlo computer model in terms of the signal-to-noise ratio, SNR, of anatomical structures corresponding to the image criteria. Both the VGAS (visual grading analysis score) and SNR decrease with increasing tube voltage in both chest PA and pelvis AP examinations, indicating superior performance if lower tube voltages are employed. Hence, a positive correlation between clinical and physical measures of image quality was found. The pros and cons of using lower tube voltages with CR digital radiography than typically used in analog screen-film radiography are discussed, as well as the relevance of using VGAS and quantum-noise SNR as measures of image quality in pelvis and chest radiography

  11. Interobserver agreement in the assessment of pulmonary infiltrates on chest radiography in community-acquired pneumonia

    International Nuclear Information System (INIS)

    Pauls, S.; Billich, C.; Boll, D.; Aschoff, A.J.; Krueger, S.; Richter, K.; Marre, R.; Gonschior, S.; Muche, R.; Welte, T.; Schumann, C.; Suttorp, N.

    2007-01-01

    Purpose: To assess interobserver agreement (IOA) in the diagnosis of pulmonary infiltrates on chest X-rays for patients with community-acquired pneumonia (CAP). Materials and methods: From 7/2002 to 12/2005, 806 adults with CAP were included in the multicenter study ''CAPNETZ'' (7 hospitals). Inclusion criteria were clinical signs of pneumonia and pulmonary opacification on chest X-rays. Each X-ray was reevaluated by two radiologists from the university hospital in consensus reading against the interpreter at the referring hospital in regard to: presence of infiltrate (yes/no/equivocal), transparency (≤/> 50%), localization, and pattern of infiltrates (alveolar/interstitial). The following parameters were documented: digital or film radiography, hospitalization, fever, findings of auscultation, microbiological findings. Results: The overall IOA concerning the detection of infiltrates was 77.7% (n 626; Cl 0.75 - 0.81), the infiltrates were not verified in 16.4% (n = 132) by the referring radiologist with equivocal findings in 5.9% (n = 48). The IOA of the different clinical centers varied between 63.2% (n = 38, Cl 0.48 - 0.78) and 92.3% (n = 65, Cl 0.86 - 0.99). The IOA for the diagnosis of infiltrates was significantly higher for inpatients with 82.6% (n = 546; Cl 0.80-0.85) than for outpatients with 55.2% (n = 80; Cl 0.47 - 0.63), p 50% was 95.1% (n = 215; Cl 0.92 - 0.98) versus 80.4% (n = 403; Cl 0.77 - 0.84) for infiltrates with a transparency > 50% (p < 0.0001). In patients with positive auscultation, the IOA was higher (p = 0,034). Chest X-rays of patients with antibiotic therapy or an alveolar infiltrate showed more equivocal findings compared to patients without these features. Conclusion: There is considerable interobserver variability in the diagnosis of pulmonary infiltrates on chest radiographs. The IOA is higher in more opaque infiltrates, positive auscultation and inpatients. (orig.)

  12. 'Soft Technique' still in use in chest radiography - Pros and Cons

    International Nuclear Information System (INIS)

    Slavchev, A.; Manolov, I.

    2004-01-01

    In recent years the number of the radiological equipment throughout the country grew immensely. It encounters old installations, new modern devices as well as and this in ever rising degree mainly imported second-hand machines or recycled ones. It is well known that the performance of a medical device and particularly of a X-ray one depends on many factors, some of them being of paramount importance for its life cycle: factory-side set characteristics, mode of operation, daily use (load), quality of service, etc. The 'soft' radiography technique (low radiation - 50 to 85 kV), due to certain conjuncture considerations used at large in this country, is totally contradicting the European criteria for image quality. Something more, it seems to be one of the most essential reasons for the higher radiation exposure of the patients and the staff. The often advocated argument to save the equipment by means of the 'soft technique' is not acceptable and taking into account the present nominal values of the basic radiological parameters/ components has categorically to be rejected. The cardinal task of the engaged service staff consists in installing/guaranteeing the technological conditions fully to meet the European norms whereas the inspector has to monitor, analyze, compare and if necessary to undertake measures to obtain this compliance. It is a matter not only of reliability and availability, the purpose consists rather in a consistent good image quality. The application of the 'hard technique' (high radiation) for chest radiography ensures not only a more complete and more precise diagnostic information but also helps in reducing the irradiation of the patient and the staff and in this manner contributes to lower the medical risk and to raise the medical diagnostic care on a higher level. (authors)

  13. Radiography

    Science.gov (United States)

    Gardner, C. G.

    1973-01-01

    Radiography is discussed as a method for nondestructive evaluation of internal flaws of solids. Gamma ray and X-ray equipment are described along with radiographic film, radiograph interpretation, and neutron radiography.

  14. Effects of tube potential and scatter rejection on image quality and effective dose in digital chest X-ray examination: An anthropomorphic phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, D.J., E-mail: daniel.shaw@christie.nhs.uk [Diagnostic Radiology, Department of Medical Physics and Engineering, Leeds Teaching Hospitals, Leeds General Infirmary, Great George Street, Leeds LS1 3EX (United Kingdom); Crawshaw, I. [Diagnostic X-ray Department, York Teaching Hospital NHS Foundation Trust, The York Hospital, Wigginton Road, York YO31 8HE (United Kingdom); Rimmer, S. D. [Diagnostic Radiology, Department of Medical Physics and Engineering, Leeds Teaching Hospitals, Leeds General Infirmary, Great George Street, Leeds LS1 3EX (United Kingdom)

    2013-11-15

    Objectives: The purpose of this study was to investigate the effects of tube potential and scatter rejection techniques on image quality of digital posteroanterior (PA) chest radiographs. Methods: An anthropomorphic phantom was imaged using a range of tube potentials (81–125 kV{sub p}) without scatter rejection, with an anti-scatter grid, and using a 10 cm air gap. Images were anonymised and randomised before being evaluated using a visual graded analysis (VGA) method. Results: The effects of tube potential on image quality were found to be negligible (p > 0.63) for the flat panel detector (FPD). Decreased image quality (p = 0.031) was noted for 125 kV{sub p} relative to 109 kV{sub p}, though no difference was noted for any of the other potentials (p > 0.398) for computed radiography (CR). Both scatter rejection techniques improved image quality (p < 0.01). For FPD imaging the anti-scatter grid offered slightly improved image quality relative to the air gap (p = 0.038) but this was not seen for CR (p = 0.404). Conclusions: For FPD chest imaging of the anthropomorphic phantom there was no dependence of image quality on tube potential. Scatter rejection improved image quality, with the anti-scatter grid giving greater improvements than an air-gap, but at the expense of increased effective dose. CR imaging of the chest phantom demonstrated negligible dependence on tube potential except at 125 kV{sub p}. Scatter rejection improved image quality, but with no difference found between techniques. The air-gap resulted in a smaller increase in effective dose than the anti-scatter grid and would be the preferred scatter rejection technique.

  15. Comparison of Digital Tomosynthesis and Chest Radiography for the Detection of Noncalcified Pulmonary and Hilar Lesions.

    Science.gov (United States)

    Galea, Angela; Adlan, Tarig; Gay, David; Roobottom, Carl; Dubbins, Paul; Riordan, Richard

    2015-09-01

    The aim of this study was to compare the sensitivity and specificity of chest digital tomosynthesis (DTS) with chest radiography (CXR) for the detection of noncalcified pulmonary nodules and hilar lesions using computed tomography (CT) as the reference standard. A total of 78 patients with suspected noncalcified pulmonary lesions on CXR were included in the study. Two radiologists, blinded to the history and CT, analyzed the CXR and the DTS images (separately), whereas a third radiologist analyzed the CXR and DTS images together. Noncalcified intrapulmonary nodules and hilar lesions were recorded for analysis. The interobserver agreement for CXR and DTS was assessed, and the time taken to report the images was recorded. A total of 202 lesions were recorded in 78 patients. There were 111 true lesions confirmed on CT in 53 patients; in 25 patients subsequent CT excluded a lesion. The overall sensitivity was 32% for CXR and 49% for DTS. This improved to 54% when the posteroanterior CXR and DTS were reviewed together (CXR-DTS). The overall specificities for CXR, DTS, and CXR-DTS were 49%, 96%, and 98%, respectively. There were 56 suspected hilar lesions with subgroup sensitivities of 76% for CXR, 65% for DTS, and 76% for CXR-DTS. The specificity for hilar lesions was 59%, 92%, and 97% for CXR, DTS, and CXR-DTS, respectively. DTS significantly improves the detectability of noncalcified nodules when compared with and when used in combination with CXR. The specificity and interobserver agreement of DTS in the diagnosis of suspected noncalcified pulmonary nodules and hilar lesions are significantly better than those of CXR and approaches those of CT.

  16. Optimisation of radiation dose and image quality in mobile neonatal chest radiography.

    Science.gov (United States)

    Hinojos-Armendáriz, V I; Mejía-Rosales, S J; Franco-Cabrera, M C

    2018-05-01

    To optimise the radiation dose and image quality for chest radiography in the neonatal intensive care unit (NICU) by increasing the mean beam energy. Two techniques for the acquisition of NICU AP chest X-ray images were compared for image quality and radiation dose. 73 images were acquired using a standard technique (56 kV, 3.2 mAs and no additional filtration) and 90 images with a new technique (62 kV, 2 mAs and 2 mm Al filtration). The entrance surface air kerma (ESAK) was measured using a phantom and compared between the techniques and against established diagnostic reference levels (DRL). Images were evaluated using seven image quality criteria independently by three radiologists. Images quality and radiation dose were compared statistically between the standard and new techniques. The maximum ESAK for the new technique was 40.20 μGy, 43.7% of the ESAK of the standard technique. Statistical evaluation demonstrated no significant differences in image quality between the two acquisition techniques. Based on the techniques and acquisition factors investigated within this study, it is possible to lower the radiation dose without any significant effects on image quality by adding filtration (2 mm Al) and increasing the tube potential. Such steps are relatively simple to undertake and as such, other departments should consider testing and implementing this dose reduction strategy within clinical practice where appropriate. Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

  17. Simulation for Teaching and Assessment of Nodule Perception on Chest Radiography in Nonradiology Health Care Trainees.

    Science.gov (United States)

    Auffermann, William F; Henry, Travis S; Little, Brent P; Tigges, Stefan; Tridandapani, Srini

    2015-11-01

    Simulation has been used as an educational and assessment tool in several fields, generally involving training of physical skills. To date, simulation has found limited application in teaching and assessment of skills related to image perception and interpretation. The goal of this pilot study was to evaluate the feasibility of simulation as a tool for teaching and assessment of skills related to perception of nodules on chest radiography. This study received an exemption from the institutional review board. Subjects consisted of nonradiology health care trainees. Subjects underwent training and assessment of pulmonary nodule identification skills on chest radiographs at simulated radiology workstations. Subject performance was quantified by changes in area under the localization receiver operating characteristic curve. At the conclusion of the study, all subjects were given a questionnaire with five questions comparing learning at a simulated workstation with training using conventional materials. Statistical significance for questionnaire responses was tested using the Wilcoxon signed rank test. Subjects demonstrated statistically significant improvement in nodule identification after training at a simulated radiology workstation (change in area under the curve, 0.1079; P = .015). Subjects indicated that training on simulated radiology workstations was preferable to conventional training methods for all questions; P values for all questions were less than .01. Simulation may be a useful tool for teaching and assessment of skills related to medical image perception and interpretation. Further study is needed to determine which skills and trainee populations may be most amenable to training and assessment using simulation. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  18. Lung Ultrasonography: A Viable Alternative to Chest Radiography in Children with Suspected Pneumonia?

    Science.gov (United States)

    Ambroggio, Lilliam; Sucharew, Heidi; Rattan, Mantosh S; O'Hara, Sara M; Babcock, Diane S; Clohessy, Caitlin; Steinhoff, Mark C; Macaluso, Maurizio; Shah, Samir S; Coley, Brian D

    2016-09-01

    To determine the interrater reliability (IRR) of lung ultrasonography (LUS) and chest radiography (CXR) and evaluate the accuracy of LUS compared with CXR for detecting pediatric pneumonia compared with chest computed tomography (CT) scan. This was a prospective cohort study of children aged 3 months to 18 years with a CXR and LUS performed between May 1, 2012, and January 31, 2014 with or without a clinical diagnosis of pneumonia. Four pediatric radiologists blinded to clinical information reported findings for the CXR and LUS images. IRR was estimated for 50 LUS and CXR images. The main outcome was the finding from CT ordered clinically or the probability of the CT finding for patients clinically requiring CT. Two radiologists reviewed CT scans to determine an overall finding. Latent class analysis was used to evaluate the sensitivity and specificity for findings (eg, consolidation) for LUS and CXR compared with CT. Of the 132 patients in the cohort, 36 (27%) had CT performed for a clinical reason. Pneumonia was clinically documented in 47 patients (36%). The IRR for lung consolidation was 0.55 (95% CI, 0.40-0.70) for LUS and 0.36 (95% CI, 0.21-0.51) for CXR. The sensitivity for detecting consolidation, interstitial disease, and pleural effusion was statistically similar for LUS and CXR compared with CT; however, specificity was higher for CXR. The negative predictive value was similar for CXR and LUS. LUS has a sufficiently high IRR for detection of consolidation. Compared with CT, LUS and CXR have similar sensitivity, but CXR is more specific for findings indicating pneumonia. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Chest radiography and thoracic computed tomography findings in children who have family members with active pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Uzum, Kazim; Karahan, Okkes I.; Dogan, Sukru; Coskun, Abdulhakim; Topcu, Faik

    2003-01-01

    Objective: The chest radiography and TCT findings in children who had contacted with adult family members with active pulmonary tuberculosis were compared. The contributions of thoracic computed tomography to the diagnosis of tuberculosis were investigated. Methods and material: The children who were 0-16 years old (n=173) and children of families with an adult member which was diagnosed as pulmonary tuberculosis were evaluated. The children were considered in two groups based on the absence (n=125) or presence (n=48) of complaints and/or ambiguous symptoms such as lack of appetite, mild cough, sweating, history of lung infection, low body weight and those with suspicious chest radiography findings (12 cases) were included in this study. Asymptomatic patients (n=125) did not undergo TCT. Patients who had positive PPD skin tests only received isoniazid. If the TCT demonstrated enlarged lymph nodes or parenchymal lesions, minimally active pulmonary tuberculosis was diagnosed and antituberculous treatment was given. Results and discussions: TCT revealed lymph node enlargement or parenchymal lesions in 39 children (81.2%). Of the 12 children whose CXRs revealed suspicious lymph node enlargement and/or infiltration, five had normal findings in TCT whereas the initial findings were confirmed in the remaining seven. These data suggest that there is a correlation between the presence of ambiguous symptoms in exposed children and TCT findings; chest radiography and TCT findings do not yield parallel findings. All the patients who received anti-TB treatment were resolved in the control examinations. Conclusion: In this study there is a correlation between presence of ambiguous symptoms and TCT findings, but the chest radiography and TCT findings do not yield harmony in exposed children with ambiguous symptoms (suspicious tuberculosis cases). These observations should be considered in children with symptoms similar to those of exposed children, but with no definite history of

  20. An evaluation of automated chest radiography reading software for tuberculosis screening among public- and private-sector patients

    OpenAIRE

    Rahman, Md Toufiq; Codlin, Andrew J.; Rahman, Md Mahfuzur; Nahar, Ayenun; Reja, Mehdi; Islam, Tariqul; Qin, Zhi Zhen; Khan, Md Abdus Shakur; Banu, Sayera; Creswell, Jacob

    2017-01-01

    Computer-aided reading (CAR) of medical images is becoming increasingly common, but few studies exist for CAR in tuberculosis (TB). We designed a prospective study evaluating CAR for chest radiography (CXR) as a triage tool before Xpert MTB/RIF (Xpert). Consecutively enrolled adults in Dhaka, Bangladesh, with TB symptoms received CXR and Xpert. Each image was scored by CAR and graded by a radiologist. We compared CAR with the radiologist for sensitivity and specificity, area under the receive...

  1. Prospective evaluation of cinefluoroscopy and chest radiography for Riata lead defects: implications for future lead screening.

    Science.gov (United States)

    Lorvidhaya, Peem; Mendoza, Ivan; Sehli, Sharmila; Atalay, Michael K; Kim, Michael H

    2013-11-01

    Lead insulation defects with externalization of the conductors exist in Riata defibrillator leads. Cinefluoroscopy is currently the gold standard to detect such defects. Prospective evaluation of alternative screening options such as chest radiography (CXR), which has been recommended by the FDA, is not well described. Patients with Riata leads underwent cinefluoroscopy, CXR, and device interrogation. Leads were classified as abnormal (clear cable separation), borderline, or normal by independent evaluation of cinefluoroscopy and CXR. CXR evaluation was done in two ways as follows: (1) routine CXR read by daily staff radiologists for lead screening and (2) CXR evaluation by a radiologist educated about the lead defect. One hundred two patients were evaluated at our institution. Cinefluoroscopy showed externalized conductors in 33 patients (32 %). Twenty-five of 33 patients (76 %) who had abnormal cinefluoroscopic findings had abnormal CXR findings on blinded review by the educated radiologist. All 25 patients with abnormal CXR had abnormal findings on cinefluoroscopy. Daily staff radiologists without direct education other than prompts for lead screening detected CXR abnormalities in only 8 out of 102 (8 %) cases. Cinefluoroscopy appears to be more sensitive than CXR for the detection of Riata cable extrusion. Interpretation of CXR by a radiologist with education in lead defects correlates highly with cinefluoroscopy with very high specificity. Depending on available resources for screening, CXR may be a reasonable alternative to cinefluoroscopy. Multidisciplinary collaboration across specialties (radiology and electrophysiology) can lead to improved diagnostic capability and thus the potential for enhanced quality of care.

  2. Tracheobronchial foreign bodies in children: importance of accurate history and plain chest radiography in delayed presentation

    Energy Technology Data Exchange (ETDEWEB)

    Tokar, B. E-mail: btokar@ogu.edu.trbarantokar@hotmail.com; Ozkan, R.; Ilhan, H

    2004-07-01

    AIM: To evaluate the factors associated with delayed diagnosis of foreign body aspiration (FBA) in children and to compare clinical, radiological and bronchoscopic findings in the patients with suspected FBA. MATERIAL AND METHODS: The medical records of 214 children who underwent bronchoscopy for suspected FBA were reviewed. The data were analysed in three groups: the patients with negative bronchoscopy for FBA (group I), early (group II) and delayed diagnosis (group III). RESULTS: The majority of the patients with FBA were between 1 and 3 years of age. Choking episodes, coughing and decreased breath sounds were determined in a significantly higher number of the patients with FBA. The plain chest radiography revealed radio-opaque foreign bodies (FBs) in 19.7% of all patients with FBA. Emphysema was more common in children with FBA. Clinical and radiological findings of pneumonia and atelectasis were significantly more common in the groups with negative bronchoscopy and with delayed diagnosis (p<0.01). The FBs were most frequently of vegetable origin, such as seeds and peanuts. A significant tissue reaction with inflammation was more common in the delayed cases. CONCLUSION: To prevent delayed diagnosis, characteristic symptoms, signs and radiological findings of FBA should be checked in all suspected cases. As clinical and radiological findings of FBA in delayed cases may mimic other disorders, the clinician must be aware of the likelihood of FBA. Regardless of radiological findings, bronchoscopy should be considered in patients with an appropriate history.

  3. Evaluation of cancer detection efficiency by means of hybrid and inverse filter in chest radiography

    International Nuclear Information System (INIS)

    Kim, Youn Young; Kim, Tae Young; Kim, Hyun Ji; Kim, Jung Min; Park, Min Seock

    2013-01-01

    The purpose of this study is to evaluate usefulness of Hybrid image and Inverse image about detection of tumor shadow in chest radiography using ROC analysis. Original images of 60 cases are selected from Standards digital image date base issued by the Japanese Society of Radiological Technology. Through computer language of C, Inverse images of 60 cases and Hybrid image of 30 cases are made. The continues reading experiment was conducted. In the case of inverse image were observed by 5 radiographer and 2 radiologist. In the case of In case of Hybrid image were observed by 3 student radiographer and 2 experienced radiographer. ROC curve are constructed using ROCKIT Program made by Metz. In Inverse image, a Az of average ROC curve was increases from 0.742 of original image to 0.775 of inverse image. In normal cases, the effect of the detrimental is same to that of the beneficial, however In abnormal cases, the beneficial effect is greater than detrimental effect. However in Hybrid image, a Az of average ROC curve was decreases from 0.5253 of original image to 0.4868 of Hybrid image. In Normal cases, the effect of the detrimental is greater than that of the Beneficial, however In abnormal cases, the Beneficial effect is greater than detrimental effect. The inverse image can be more positively considered for the detecting of tumor than the hybrid image

  4. Variability and accuracy in interpretation of consolidation on chest radiography for diagnosing pneumonia in children under 5 years of age.

    Science.gov (United States)

    Williams, Gabrielle J; Macaskill, Petra; Kerr, Marianne; Fitzgerald, Dominic A; Isaacs, David; Codarini, Miriam; McCaskill, Mary; Prelog, Kristina; Craig, Jonathan C

    2013-12-01

    Consolidation on chest radiography is widely used as the reference standard for defining pneumonia and variability in interpretation is well known but not well explored or explained. Three pediatric sub-specialists (infectious diseases, radiology and respiratory medicine) viewed 3,033 chest radiographs in children aged under 5 years of age who presented to one Emergency Department (ED) with a febrile illness. Radiographs were viewed blind to clinical information about the child and blind to findings of other readers. Each chest radiograph was identified as positive or negative for consolidation. Percentage agreement and kappa scores were calculated for pairs of readers. Prevalence of consolidation and reader sensitivity/specificity was estimated using latent class analysis. Using the majority rule, 456 (15%) chest radiographs were positive for consolidation while the latent class estimate was 17%. The radiologist was most likely (21.3%) and respiratory physician least likely (13.7%) to diagnose consolidation. Overall percentage agreement for pairs of readers was 85-90%. However, chance corrected agreement between the readers was moderate, with kappa scores 0.4-0.6 and did not vary with patient characteristics (age, gender, and presence of chronic illness). Estimated sensitivity ranged from 0.71 to 0.81 across readers, and specificity 0.91 to 0.98. Overall agreement for identification of consolidation on chest radiographs was good, but agreement adjusted for chance was only moderate and did not vary with patient characteristics. Clinicians need to be aware that chest radiography is an imperfect test for diagnosing pneumonia and has considerable variability in its interpretation. © 2013 Wiley Periodicals, Inc.

  5. Digital radiography is promising in industrial testing

    International Nuclear Information System (INIS)

    Del Fabbro, F.

    2015-01-01

    Digital radiography has recently entered the industrial world as a tool for non-destructive testing. There are 3 types of digital radiography: computed radiography (CR), direct radiography (DR) and computed tomography (CT). In computed radiography, traditional silver-halide films are replaced by photostimulable phosphor imaging plates that are activated through laser scanning and digitized. Direct radiography uses a flat panel detector (FPD) composed of X-ray detectors that performs an immediate digital conversion of the image that can be read by a computer. DR is a perfect tool for industrial testing but the fragility of the FPD panels reduces its uses. Computed tomography is based on the principle of DR to get data corresponding to successive cross-section images of the object. These data are processed by a software to get a 3-dimensional image of the object. CT was first developed for medical use but requires some improvement to become more accurate, faster, particularly for big objects. In recent years DR has enjoyed the highest growth rate in digital radiography. (A.C.)

  6. Chest radiography patterns in 75 adolescents with vertically-acquired human immunodeficiency virus (HIV) infection

    International Nuclear Information System (INIS)

    Desai, S.R.; Copley, S.J.; Barker, R.D.; Elston, C.M.; Miller, R.F.; Wells, A.U.; Munyati, S.; Nathoo, K.; Corbett, E.L.; Ferrand, R.A.

    2011-01-01

    Aim: To evaluate lung disease on chest radiography (CR), the relative frequency of CR abnormalities, and their clinical correlates in adolescents with vertically-acquired human immunodeficiency virus (HIV) infection. Materials and methods: CRs of 75 patients [59 inpatients (33 males; mean age 13.7 ± 2.3 years) and 16 outpatients (eight males; mean age 14.1 ± 2.1 years)] were retrospectively reviewed by three independent observers. The overall extent of disease (to the nearest 5%), its distribution, and the proportional extents (totalling 100%) of different radiographic patterns (including ring/tramline opacities and consolidation) were quantified. CR features and clinical data were compared. Results: CRs were abnormal in 51/75 (68%) with 'extensive' disease in 38/51 (74%). Ring/tramline opacities and consolidation predominated (i.e., proportional extent >50%) in 26 and 21 patients, respectively. Consolidation was significantly more common in patients hospitalized primarily for a respiratory illness than patients hospitalized for a non-respiratory illness or in outpatients (p 2 for trend); by contrast, ring/tramline opacities did not differ in prevalence across the groups. On stepwise logistic regression, predominant consolidation was associated with progressive dyspnoea [odds ratio (OR) 5.60; 95% confidence intervals (CI): 1.60, 20.1; p < 0.01] and was associated with a primary respiratory cause for hospital admission (OR: 22.0; CI: 2.7, 181.1; p < 0.005). Ring/tramline opacities were equally prevalent in patients with and without chronic symptoms and in those admitted to hospital with respiratory and non-respiratory illness. Conclusion: In HIV-infected adolescents, evaluated in secondary practice, CR abnormalities are prevalent. The presence of ring/tramline opacities, believed to reflect chronic airway disease, is not linked chronic respiratory symptoms.

  7. Chest radiography patterns in 75 adolescents with vertically-acquired human immunodeficiency virus (HIV) infection

    Energy Technology Data Exchange (ETDEWEB)

    Desai, S.R., E-mail: sujal.desai@nhs.ne [King' s College London, King' s Health Partners, Department of Radiology, King' s College Hospital NHS Foundation Trust (United Kingdom); Copley, S.J. [Department of Radiology, Hammersmith Hospital (United Kingdom); Barker, R.D.; Elston, C.M. [King' s College London, King' s Health Partners, Department of Respiratory Medicine, King' s College Hospital NHS Foundation Trust (United Kingdom); Miller, R.F. [Research Department of Infection and Public Health, Division of Population Health, University College London (United Kingdom); Clinical Research Unit, London School of Hygiene and Tropical Medicine, London (United Kingdom); Wells, A.U. [The Interstitial Lung Disease Unit, Royal Brompton and Harefield NHS Trust, London (United Kingdom); Munyati, S. [Biomedical Research and Training Institute, Samora Machel Avenue (Zimbabwe); Nathoo, K. [Department of Paediatrics, University of Zimbabwe (Zimbabwe); Harare Central Hospital, Lobengula Road, Harare (Zimbabwe); Corbett, E.L.; Ferrand, R.A. [Clinical Research Unit, London School of Hygiene and Tropical Medicine, London (United Kingdom); Biomedical Research and Training Institute, Samora Machel Avenue (Zimbabwe)

    2011-03-15

    Aim: To evaluate lung disease on chest radiography (CR), the relative frequency of CR abnormalities, and their clinical correlates in adolescents with vertically-acquired human immunodeficiency virus (HIV) infection. Materials and methods: CRs of 75 patients [59 inpatients (33 males; mean age 13.7 {+-} 2.3 years) and 16 outpatients (eight males; mean age 14.1 {+-} 2.1 years)] were retrospectively reviewed by three independent observers. The overall extent of disease (to the nearest 5%), its distribution, and the proportional extents (totalling 100%) of different radiographic patterns (including ring/tramline opacities and consolidation) were quantified. CR features and clinical data were compared. Results: CRs were abnormal in 51/75 (68%) with 'extensive' disease in 38/51 (74%). Ring/tramline opacities and consolidation predominated (i.e., proportional extent >50%) in 26 and 21 patients, respectively. Consolidation was significantly more common in patients hospitalized primarily for a respiratory illness than patients hospitalized for a non-respiratory illness or in outpatients (p < 0.005, {chi}{sup 2} for trend); by contrast, ring/tramline opacities did not differ in prevalence across the groups. On stepwise logistic regression, predominant consolidation was associated with progressive dyspnoea [odds ratio (OR) 5.60; 95% confidence intervals (CI): 1.60, 20.1; p < 0.01] and was associated with a primary respiratory cause for hospital admission (OR: 22.0; CI: 2.7, 181.1; p < 0.005). Ring/tramline opacities were equally prevalent in patients with and without chronic symptoms and in those admitted to hospital with respiratory and non-respiratory illness. Conclusion: In HIV-infected adolescents, evaluated in secondary practice, CR abnormalities are prevalent. The presence of ring/tramline opacities, believed to reflect chronic airway disease, is not linked chronic respiratory symptoms.

  8. Screening strategies for tuberculosis prevalence surveys: the value of chest radiography and symptoms.

    Directory of Open Access Journals (Sweden)

    Anna H van't Hoog

    Full Text Available We conducted a tuberculosis (TB prevalence survey and evaluated the screening methods used in our survey, to assess if screening in TB prevalence surveys could be simplified, and to assess the accuracy of screening algorithms that may be applicable for active case finding.All participants with a positive screen on either a symptom questionnaire, chest radiography (CXR and/or sputum smear microscopy submitted sputum for culture. HIV status was obtained from prevalent cases. We estimated the accuracy of modified screening strategies with bacteriologically confirmed TB as the gold standard, and compared these with other survey reports. We also assessed whether sequential rather than parallel application of symptom, CXR and HIV screening would substantially reduce the number of participants requiring CXR and/or sputum culture.Presence of any abnormality on CXR had 94% (95%CI 88-98 sensitivity (92% in HIV-infected and 100% in HIV-uninfected and 73% (95%CI 68-77 specificity. Symptom screening combinations had significantly lower sensitivity than CXR except for 'any TB symptom' which had 90% (95%CI 84-95 sensitivity (96% in HIV-infected and 82% in HIV-uninfected and 32% (95%CI 30-34 specificity. Smear microscopy did not yield additional suspects, thus the combined symptom/CXR screen applied in the survey had 100% (95%CI 97-100 sensitivity. Specificity was 65% (95%CI 61-68. Sequential application of first a symptom screen for 'any symptom', followed by CXR-evaluation and different suspect criteria depending on HIV status would result in the largest reduction of the need for CXR and sputum culture, approximately 36%, but would underestimate prevalence by 11%.CXR screening alone had higher accuracy compared to symptom screening alone. Combined CXR and symptom screening had the highest sensitivity and remains important for suspect identification in TB prevalence surveys in settings where bacteriological sputum examination of all participants is not

  9. Multiple-energy tissue-cancellation applications of a digital beam attenuator to chest radiography

    International Nuclear Information System (INIS)

    Dobbins, J.T. III.

    1985-01-01

    The digitally-formed primary beam attenuator (DBA) spatially modulates the x-ray fluence incident upon the patient to selectively attenuate regions of interest. The DBA attenuating mask is constructed from CeO 2 powder by a modified printing technique and uses image information from an initial low-dose exposure. Two tissue-cancellation imaging techniques are investigated with the DBA: (1) energy-dependent information is used to form a beam attenuator that attenuates specific tissues in the primary x-ray beam for tissue-cancelled film radiography; (2) the beam attenuator is used to improve image signal-to-noise and scattered radiation properties in traditional energy-subtraction tissue-cancellation imaging with digital detectors. The tissue-cancellation techniques in the primary x-ray beam were capable of adequately removing either soft-tissue or bone from the final compensated film radiograph when using a phantom with well defined soft-tissue and bone sections. However, when tried on an anthropomorphic chest phantom the results were adequate for cancellation of large soft tissue structures, but unsatisfactory for cancellation of bony structures such as the ribs, because of the limited spatial frequency content of the attenuating mask. The second technique (with digital detectors) showed improved uniformity of image signal-to-noise and a two-fold increase in soft-tissue nodule contrast due to improved scattered radiation properties. The tissue-cancelled images contained residual image contributions from the presence of the attenuating mask, but this residual may be correctable by future algorithms

  10. What is the yield of routine chest radiography following tube thoracostomy for trauma?

    Science.gov (United States)

    Kong, Victor Y; Oosthuizen, George V; Clarke, Damian L

    2015-01-01

    Routine chest radiography (CXR) following tube thoracostomy (TT) is a standard practice in most trauma centres worldwide. Evidence supporting this routine practice is lacking and the actual yield is unknown. We performed a retrospective review of 1042 patients over a 4-year period who had a routine post-insertion CXR performed in accordance with current ATLS® recommendations. A total 1042 TTs were performed on 1004 patients. Ninety-one per cent of patients (913/1004) were males, and the median age for all patients was 24 years. Seventy-five per cent of all injuries (756/1004) were from penetrating trauma, and the remaining 25% (248/1004) were from blunt. The initial pathologies requiring TT were: haemopneumothorax: 34% (339/1042), haemothroax: 31% (314/1042), simple pneumothorax: 25% (256/1042), tension pneumothorax: 8% (77/1042) and open pneumothorax: 5% (54/1042). One hundred and three patients had TTs performed on clinical grounds alone without a pre-insertion CXR [Group A]. One hundred and ninety-one patients had a pre-insertion CXR but had persistent clinical concerns following insertion [Group B]. Seven hundred and ten patients had pre-insertion CXR but no clinical concerns following insertion [Group C]. Overall, 15% (152/1004) [9 from Group A, 111 from Group B and 32 from Group C] of all patients had their clinical management influenced as a direct result of the post-insertion CXR. Despite the widely accepted practice of routine CXR following tube thoracostomy, the yield is relatively low. In many cases, good clinical examination post tube insertion will provide warnings as to whether problems are likely to result. However, in the more rural setting, and in resource challenged environments, there is a relatively high yield from the CXR, which alters management. Further prospective studies are needed to establish or refute the role of the existing ATLS® guidelines in these specific environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Anthropomorphic chest phantom imaging – The potential for dose creep in computed radiography

    International Nuclear Information System (INIS)

    Ma, W.K.; Hogg, P.; Tootell, A.; Manning, D.; Thomas, N.; Kane, T.; Kelly, J.; McKenzie, M.; Kitching, J.

    2013-01-01

    For film-based radiography the operator had to be exact in the selection of acquisition parameters or the image could easily become under- or over-exposed. By contrast, digital technology allows for a much greater tolerance of acquisition factor selection which would still give an image of acceptable diagnostic quality. In turn this greater tolerance allows for the operator to increase effective dose for little or no penalty in image quality. The purpose of this article is to determine how image quality and lesion visibility vary with effective dose (E) in order to identify how much overexposure could be tolerated within the radiograph. Using an anthropomorphic chest phantom with ground glass lesions we determined how perceptual image quality and E varied over a wide range of acquisition conditions. Perceptual image quality comprised of image quality and lesion visibility. E was calculated using Monte Carlo method; image quality was determined using a two alternative forced choice (2AFC) method and the quality criteria were partly informed from European guidelines. Five clinicians with significant experience in image reading scored the images for quality (intraclass correlation coefficient 0.869). Image quality and lesion visibility had a close correlation (R 2 > 0.8). The tolerance for over-exposure, whilst still acquiring an image of acceptable quality, increases with decreasing kV and increasing source to image distance (SID). The maximum over-exposure factor (ratio of maximum E to minimum E that produce images of acceptable quality) possible was 139 (at 125 cm and 60 kV). Given the phantom had characteristics similar to the human thorax we propose that that potential for overexposure in a human whilst still obtaining an image of acceptable perceptual image quality is very high. Further research into overexposure tolerance and dose creep should be undertaken

  12. Small lung cancers: improved detection by use of bone suppression imaging--comparison with dual-energy subtraction chest radiography.

    Science.gov (United States)

    Li, Feng; Engelmann, Roger; Pesce, Lorenzo L; Doi, Kunio; Metz, Charles E; Macmahon, Heber

    2011-12-01

    To determine whether use of bone suppression (BS) imaging, used together with a standard radiograph, could improve radiologists' performance for detection of small lung cancers compared with use of standard chest radiographs alone and whether BS imaging would provide accuracy equivalent to that of dual-energy subtraction (DES) radiography. Institutional review board approval was obtained. The requirement for informed consent was waived. The study was HIPAA compliant. Standard and DES chest radiographs of 50 patients with 55 confirmed primary nodular cancers (mean diameter, 20 mm) as well as 30 patients without cancers were included in the observer study. A new BS imaging processing system that can suppress the conspicuity of bones was applied to the standard radiographs to create corresponding BS images. Ten observers, including six experienced radiologists and four radiology residents, indicated their confidence levels regarding the presence or absence of a lung cancer for each lung, first by using a standard image, then a BS image, and finally DES soft-tissue and bone images. Receiver operating characteristic (ROC) analysis was used to evaluate observer performance. The average area under the ROC curve (AUC) for all observers was significantly improved from 0.807 to 0.867 with BS imaging and to 0.916 with DES (both P chest radiographs. Further improvements can be achieved by use of DES radiography but with the requirement for special equipment and a potential small increase in radiation dose. © RSNA, 2011.

  13. Stationary chest tomosynthesis using a carbon nanotube x-ray source array: a feasibility study

    International Nuclear Information System (INIS)

    Shan, Jing; Lee, Yueh Z; Lu, Jianping; Zhou, Otto; Tucker, Andrew W; Heath, Michael D; Wang, Xiaohui; Foos, David H

    2015-01-01

    Chest tomosynthesis is a low-dose, quasi-3D imaging modality that has been demonstrated to improve the detection sensitivity for small lung nodules, compared to 2D chest radiography. The purpose of this study is to investigate the feasibility and system requirements of stationary chest tomosynthesis (s-DCT) using a spatially distributed carbon nanotube (CNT) x-ray source array, where the projection images are collected by electronically activating individual x-ray focal spots in the source array without mechanical motion of the x-ray source, detector, or the patient. A bench-top system was constructed using an existing CNT field emission source array and a flat panel detector. The tube output, beam quality, focal spot size, system in-plane and in-depth resolution were characterized. Tomosynthesis slices of an anthropomorphic chest phantom were reconstructed for image quality assessment. All 75 CNT sources in the source array were shown to operate reliably at 80 kVp and 5 mA tube current. Source-to-source consistency in the tube current and focal spot size was observed. The incident air kerma reading per mAs was measured as 74.47 uGy mAs −1 at 100 cm. The first half value layer of the beam was 3 mm aluminum. An average focal spot size of 2.5  ×  0.5 mm was measured. The system MTF was measured to be 1.7 cycles mm −1 along the scanning direction, and 3.4 cycles mm −1 perpendicular to the scanning direction. As the angular coverage of 11.6°–34°, the full width at half maximum of the artifact spread function improved greatly from 9.5 to 5.2 mm. The reconstructed tomosynthesis slices clearly show airways and pulmonary vascular structures in the anthropomorphic lung phantom. The results show the CNT source array is capable of generating sufficient dose for chest tomosynthesis imaging. The results obtained so far suggest an s-DCT using a distributed CNT x-ray source array is feasible. (paper)

  14. Dose reduction of radiographs of the pediatric pelvis for diagnosing hip dysplasia using a digital flat-panel detector system; Dosisreduktion bei Roentgenaufnahmen des kindlichen Beckenskelettes zur Diagnostik der Hueftgelenksdysplasie unter Verwendung eines digitalen Flachdetektorsystems

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, K.; Ahlers, K.; Kloska, S.; Vieth, V.; Meier, N.; Heindel, W. [Inst. fuer Klinische Radiologie, Westfaelische Wilhelms-Univ. Muenster (Germany); Sandmann, C.; Gosheger, G. [Orthopaedische Klinik, Westfaelische Wilhelms-Univ. Muenster (Germany)

    2003-01-01

    Purpose: To evaluate a possible dose reduction in pediatric pelvic radiographs in congenital hip dysplasia using a digital flat-panel system instead of a phosphor-storage system. Materials and Methods: During a six-month period, all pediatric patients referred for pelvic radiography for the evaluation of congenital hip dysplasia were randomely assigned to be examined by either a phosphor-storage system or a digital flat-panel system, whereby the latter system was operated with half the radiation dose. Thirty pairs of radiographs were assessed for the visibility of 16 anatomic details and for 5 orthopedic-radiographic measurements (5-point scale with 1 = excellent; three independent observers). The projection indices of Ball and Kommenda and of Toennis and Brunken were calculated for all radiographs. The Student's t-test was used to compare the flat-panel and the phosphor-storage radiographs for observers' assessments, patients' age and projection indices. Results: In a total of 7560 observations, the scores for the visibility of anatomic details and orthopedic-radiographic measurements were respectively 2.72 and 2.64 for the flat-panel system and 2.93 and 2.79 for the phosphor-storage system. No significant differences were found between both systems (p > 0.05) and between patient age and projection indices (p > 0.05). Conclusion: Pediatric pelvic radiographs can be obtained with a digital flat-panel system using half the radiation dose instead of a phosphor-storage system without sacrificing relevant information in the diagnosis of congenital hip dysplasia. (orig.) [German] Zielsetzung: Evaluation einer moeglichen Dosisreduktion bei kindlichen Beckenroentgenaufnahmen zur Diagnostik der Hueftgelenksdysplasie mit einem digitalen Flachdetektorsystem im Vergleich zu einem digitalen Speicherfoliensystem. Material und Methoden: Prospektiv wurden alle ueber einen Zeitraum von 6 Monaten zur Roentgenaufnahme des Beckenskelettes im Rahmen der Diagnostik der

  15. Estimation of exposed radiation dose in radiography of the chest. Mainly on the dose at health examination on automobiles

    International Nuclear Information System (INIS)

    Suzuki, Shoichi; Oda, Akiko; Ohkura, Masaki

    1998-01-01

    The exposure doses in radiography and photofluorography of the chest at health examination on automobiles were estimated and compared with those using other hospital equipments. The tube voltage, effective energy and half value layer under ordinary conditions for radiography and fluorography were measured by KYOKKO model 100 X-ray analyzer and output pulse shape was confirmed by the fluorometer (TOREKEY-1001 C). The dose at the body surface was measured by the ionization chambers (VICTOREEN RADCON 500 and 30-330) which had been equipped in the WAC chest phantom (JIS Z 4915, Kyoto Kagaku). Nine automobiles of 3 facilities were used, of which X-ray generating apparatuses of either condenser or inverter type were manufactured by Hitachi (5 machines), Toshiba (1) and Shimadzu (3). The examined apparatuses not for the automobile were Toshiba-20 and Hitachi SIRIUS-100 portable ones and Hitachi DH-1520 TM high-voltage one. The effective energy was found dependent on the tube voltage (100-130 kV) and X-ray generating system (35.1-54.37 keV in the condenser type and 41.1-43.9 keV in the inverter type). Pulse shape analysis revealed that the pulse height and area under the pulse height-time curve were larger in the inverter system. The mean doses in photofluorography and radiography on automobiles were 0.525 and 0.297 mGy, respectively. The mean dose of 0.61 mGy in radiography at home with the portable apparatus was the highest even when compared with that of 0.525 mGy for fluorography on the automobile. Thus, the inverter system on the car can guarantee the level of 0.4 mGy defined by IAEA guideline (Safety series No. 115, 1996). (K.H.)

  16. Chest and spine radiography abnormality in blunt chest trauma correlated with major vessel injury in an unselected patient population

    International Nuclear Information System (INIS)

    Fernandez, G.; Kadir, S.; Encarnacion, C.

    1989-01-01

    To assess the true incidence of major vessel injury, the authors retrospectively reviewed all arch aortograms obtained for blunt chest trauma (BCT) during a 24-month period beginning December 1986. Aortograms were correlated with preangiographic chest radiographic and operative findings. The goals of this review were to examine the usefulness of commonly employed screening criteria for aortography and determine whether thoracic spine fractures imply a decreased likelihood of aortic injury. One hundred twenty aortograms were obtained during this period. The incidence of aortic laceration was 6.7%, and 7.5% had brachiocerebral vascular injury. Only 51% of chest radiographs were suggestive of vascular injury. Two patients with subtle radiographic findings had aortic laceration. One patient with a burst fracture of T-4 had aortic laceration. The results of this review indicate the incidence of great vessel injury is as high as that of injury to the aorta itself and that the presence of spine fractures does not exclude vascular injury

  17. Accuracy of chest radiography for positioning of the umbilical venous catheter

    Directory of Open Access Journals (Sweden)

    Adriana F.M. Guimarães

    2017-03-01

    Full Text Available Objectives: To evaluate the accuracy of the simultaneous analysis of three radiographic anatomical landmarks – diaphragm, cardiac silhouette, and vertebral bodies – in determining the position of the umbilical venous catheter distal end using echocardiography as a reference standard. Methods: This was a cross-sectional, observational study, with the prospective inclusion of data from all neonates born in a public reference hospital, between April 2012 and September 2013, submitted to umbilical venous catheter insertion as part of their medical care. The position of the catheter distal end, determined by the simultaneous analysis of three radiographic anatomical landmarks, was compared with the anatomical position obtained by echocardiography; sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. Results: Of the 162 newborns assessed by echocardiography, only 44 (27.16% had the catheter in optimal position, in the thoracic portion of the inferior vena cava or at the junction of the inferior vena cava with the right atrium. The catheters were located in the left atrium and interatrial septum in 54 (33.33% newborns, in the right atrium in 26 (16.05%, intra-hepatic in 37 (22.84%, and intra-aortic in-one newborn (0.62%. The sensitivity, specificity and accuracy of the radiography to detect the catheter in the target area were 56%, 71%, and 67.28%, respectively. Conclusion: Anteroposterior radiography of the chest alone is not able to safely define the umbilical venous catheter position. Echocardiography allows direct visualization of the catheter tip in relation to vascular structures and, whenever possible, should be considered to identify the location of the umbilical venous catheter. Resumo: Objetivos: Avaliar a acurácia da análise simultânea dos três marcos anatômicos radiográficos – diafragma, silhueta cardíaca e corpos vertebrais, na determinação da posição da extremidade

  18. A novel radiation detector for removing scattered radiation in chest radiography: Monte Carlo simulation-based performance evaluation

    Science.gov (United States)

    Roh, Y. H.; Yoon, Y.; Kim, K.; Kim, J.; Kim, J.; Morishita, J.

    2016-10-01

    Scattered radiation is the main reason for the degradation of image quality and the increased patient exposure dose in diagnostic radiology. In an effort to reduce scattered radiation, a novel structure of an indirect flat panel detector has been proposed. In this study, a performance evaluation of the novel system in terms of image contrast as well as an estimation of the number of photons incident on the detector and the grid exposure factor were conducted using Monte Carlo simulations. The image contrast of the proposed system was superior to that of the no-grid system but slightly inferior to that of the parallel-grid system. The number of photons incident on the detector and the grid exposure factor of the novel system were higher than those of the parallel-grid system but lower than those of the no-grid system. The proposed system exhibited the potential for reduced exposure dose without image quality degradation; additionally, can be further improved by a structural optimization considering the manufacturer's specifications of its lead contents.

  19. Digital chest radiography: an update on modern technology, dose containment and control of image quality

    NARCIS (Netherlands)

    Schaefer-Prokop, Cornelia; Neitzel, Ulrich; Venema, Henk W.; Uffmann, Martin; Prokop, Mathias

    2008-01-01

    The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose

  20. Analysis of image quality according to BMI of digital chest radiography: Focusing on bureau of radiological health evaluation

    International Nuclear Information System (INIS)

    Jin, Seong Jin; Im, In Chul; Cho, Ji Hwan

    2017-01-01

    Visual evaluation of chest radiograph images is the most practical and effective method. This study compared the Body Mass Index, waist circumference, and mAs with chest radiographs of 351 women. The Bureau of Radiological Health method was used to evaluate the image quality of chest X-ray images by anatomical and physical methods. The average age of the subjects was 30.17±4.73 and the average waist circumference was 66.91±4.67 cm. The mean Body Mass Index value was 20.21±2.23, the mean value of mAs was 3.04±0.78, and the mean value of Bureau of Radiological Health was 79.83±8.45. When the Body Mass Index value increased, waist circumference and mAs mean value increased. The mean value of Body Mass Index was statistically significant(p<0.05) in Group 4 compared to Groups 1 and 2, with increasing Body Mass Index. Exposure control of the automatic exposure control system is considered to be well performed according to body thickness or Body Mass Index at the time of chest radiography. As the Body Mass Index increases, the thickness of the body increases and the breast thickness of the woman also increases. Therefore, it is considered that the exposure amount is changed by the automatic exposure control device to affect the image quality

  1. Analysis of image quality according to BMI of digital chest radiography: Focusing on bureau of radiological health evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Seong Jin [Gammaknife center, Inje University Haeundae Paik Hospital, Busan (Korea, Republic of); Im, In Chul [Dept. of Radiological Science, Dongeui University, Busan (Korea, Republic of); Cho, Ji Hwan [Dept. of Health Care Clinic, Inje University Busan Paik Hospital, Busan (Korea, Republic of)

    2017-03-15

    Visual evaluation of chest radiograph images is the most practical and effective method. This study compared the Body Mass Index, waist circumference, and mAs with chest radiographs of 351 women. The Bureau of Radiological Health method was used to evaluate the image quality of chest X-ray images by anatomical and physical methods. The average age of the subjects was 30.17±4.73 and the average waist circumference was 66.91±4.67 cm. The mean Body Mass Index value was 20.21±2.23, the mean value of mAs was 3.04±0.78, and the mean value of Bureau of Radiological Health was 79.83±8.45. When the Body Mass Index value increased, waist circumference and mAs mean value increased. The mean value of Body Mass Index was statistically significant(p<0.05) in Group 4 compared to Groups 1 and 2, with increasing Body Mass Index. Exposure control of the automatic exposure control system is considered to be well performed according to body thickness or Body Mass Index at the time of chest radiography. As the Body Mass Index increases, the thickness of the body increases and the breast thickness of the woman also increases. Therefore, it is considered that the exposure amount is changed by the automatic exposure control device to affect the image quality.

  2. Chest X-Ray

    Medline Plus

    Full Text Available ... talk with you about chest radiography also known as chest x-rays. Chest x-rays are the ... treatment for a variety of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray ...

  3. Comparison of the perceived image quality between two digital imaging systems for neonatal bedside radiography – A case study

    International Nuclear Information System (INIS)

    Zyl, S.A. van; Kekana, R.M.

    2015-01-01

    Background: Chest X-rays are performed daily in the neonatal intensive care and high care units. The skill of the radiographer is critical for obtaining the best image quality and limiting the patient's radiation exposure. The literature states that indirect flat panel detectors produce images of superior quality in comparison to computed radiography systems. At Steve Biko Academic Hospital a decision was made to revert from the direct digital radiography (DR) system to the computed radiography (CR) system, due to poor image quality experienced. Method: The case study objective was to conduct a comparative analysis describing key technical factors contributing to image quality. The analysis entailed retrospectively comparing the images obtained during 2010 and 2011. An image analysis form was utilised in evaluating the technical aspects of the image. A total of 160 images were viewed by 16 participants sampled from the radiography, radiology and paediatric departments. The participants were asked to re-evaluate two of their allotted images after five days to determine their reliability. Results: Findings were that the DR system provides significantly better image quality than the CR system (p < 0.05) for all the technical factors evaluated. However technical improvements are recommended. A wide variance in intra-observer reliability was also found. Conclusion: This case study demonstrated that DR images were considered to be superior to CR images. Recommendations include: a standardised technique for imaging the neonates; optimisation of the imaging software for the digital detectors, improved feedback systems in terms of exposure index values, and the training of radiographers and referring physicians in technical image analysis. - Highlights: • DR system provides better image quality than the CR system for all technical factors evaluated. • The average values obtained from the VAS showed that the DR system still needs to be optimised. • There is need

  4. Image quality and dose management in digital radiography: A new paradigm for optimisation

    International Nuclear Information System (INIS)

    Busch, H. P.; Faulkner, K.

    2005-01-01

    The advent of digital imaging in radiology, combined with the explosive growth of technology, has dramatically improved imaging techniques. This has led to the expansion of diagnostic capabilities, both in terms of the number of procedures and their scope. Throughout the world, film/ screen radiography systems are being rapidly replaced with digital systems. Many progressive medical institutions have acquired, or are considering the purchase of computed radiography systems with storage phosphor plates or direct digital radiography systems with flat panel detectors. However, unknown to some users, these devices offer a new paradigm of opportunity and challenges. Images can be obtained at a lower dose owing to the higher detective quantum efficiency (DQE). These fundamental differences in comparison to conventional film/screens necessitate the development of new strategies for dose and quality optimisations. A set of referral criteria based upon three dose levels is proposed. (authors)

  5. Computer-aided detection system for chest radiography: reducing report turnaround times of examinations with abnormalities.

    Science.gov (United States)

    Kao, E-Fong; Liu, Gin-Chung; Lee, Lo-Yeh; Tsai, Huei-Yi; Jaw, Twei-Shiun

    2015-06-01

    The ability to give high priority to examinations with pathological findings could be very useful to radiologists with large work lists who wish to first evaluate the most critical studies. A computer-aided detection (CAD) system for identifying chest examinations with abnormalities has therefore been developed. To evaluate the effectiveness of a CAD system on report turnaround times of chest examinations with abnormalities. The CAD system was designed to automatically mark chest examinations with possible abnormalities in the work list of radiologists interpreting chest examinations. The system evaluation was performed in two phases: two radiologists interpreted the chest examinations without CAD in phase 1 and with CAD in phase 2. The time information recorded by the radiology information system was then used to calculate the turnaround times. All chest examinations were reviewed by two other radiologists and were divided into normal and abnormal groups. The turnaround times for the examinations with pathological findings with and without the CAD system assistance were compared. The sensitivity and specificity of the CAD for chest abnormalities were 0.790 and 0.697, respectively, and use of the CAD system decreased the turnaround time for chest examinations with abnormalities by 44%. The turnaround times required for radiologists to identify chest examinations with abnormalities could be reduced by using the CAD system. This system could be useful for radiologists with large work lists who wish to first evaluate the most critical studies. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. [Imaging of pleural diseases: evaluation of imaging methods based on chest radiography].

    Science.gov (United States)

    Poyraz, Necdet; Kalkan, Havva; Ödev, Kemal; Ceran, Sami

    2017-03-01

    The most commonly employed radiologic method in diagnosis of pleural diseases is conventional chest radiograph. The commonest chest- X-Ray findings are the presence of pleural effusion and thickening. Small pleural effusions are not readily identified on posteroanterior chest radiograph. However, lateral decubitus chest radiograph and chest ultrasonography may show small pleural effusions. These are more efficient methods than posteroanterior chest radiograph in the erect position for demonstrating small amounts of free pleural effusions. Chest ultrasonograph may be able to help in distinguishing the pleural pathologies from parenchymal lesions. On chest radiograph pleural effusions or pleural thickening may obscure the visibility of the underlying disease or parenchymal abnormality. Thus, computed tomography (CT) may provide additional information of determining the extent and severity of pleural disease and may help to differentiate malign pleural lesions from the benign ones. Moreover, CT may provide the differentiation of parenchmal abnormalities from pleural pathologies. CT (coronal and sagittal reformatted images) that also show invasion of chest wall, mediastinum and diaphragm, as well as enlarged hilar or mediastinal lymph nodes. Standart non-invasive imaging techniques may be supplemented with magnetic resonans imaging (MRI).

  7. Flat-panel detectors: how much better are they?

    International Nuclear Information System (INIS)

    Seibert, J.A.

    2006-01-01

    Interventional and fluoroscopic imaging procedures for pediatric patients are becoming more prevalent because of the less-invasive nature of these procedures compared to alternatives such as surgery. Flat-panel X-ray detectors (FPD) for fluoroscopy are a new technology alternative to the image intensifier/TV (II/TV) digital system that has been in use for more than two decades. Two major FPD technologies have been implemented, based on indirect conversion of X-rays to light (using an X-ray scintillator) and then to proportional charge (using a photodiode), or direct conversion of X-rays into charge (using a semiconductor material) for signal acquisition and digitization. These detectors have proved very successful for high-exposure interventional procedures but lack the image quality of the II/TV system at the lowest exposure levels common in fluoroscopy. The benefits for FPD image quality include lack of geometric distortion, little or no veiling glare, a uniform response across the field-of-view, and improved ergonomics with better patient access. Better detective quantum efficiency indicates the possibility of reducing the patient dose in accordance with ALARA principles. However, first-generation FPD devices have been implemented with less than adequate acquisition flexibility (e.g., lack of tableside controls/information, inability to easily change protocols) and the presence of residual signals from previous exposures, and additional cost of equipment and long-term maintenance have been serious impediments to purchase and implementation. Technological advances of second generation and future hybrid FPD systems should solve many current issues. The answer to the question ''how much better are they?'' is ''significantly better'', and they are certainly worth consideration for replacement or new implementation of an imaging suite for pediatric fluoroscopy. (orig.)

  8. Application of a simple phantom in assessing the effects of dose reduction on image quality in chest radiography

    International Nuclear Information System (INIS)

    Egbe, N.O.; Heaton, B.; Sharp, P.F.

    2010-01-01

    Purpose: Firstly, to evaluate a commercial chest phantom incorporating a quasi anthropomorphic insert by comparing exposure measurements on the phantom with those of actual patients and, secondly, to assess the value of the phantom for image quality and dose optimisation. Methods: In the first part of the study entrance surface doses (ESD), Beam transmission (BT), and optical density (OD) were obtained for 77 chest radiography patients and compared with measurements made from exposures of the phantom using the respective patient exposure factors from chest examination. Differences were assessed with a student t-test, while the Pearson's linear correlation coefficient was used to test for any linear relationship. The second part assessed the applicability of the phantom to image quality studies by investigating the effect, on the clarity and detectability of lung lesions made from gelatine, of reducing patient dose below current dose levels. Clarity of linear objects of different dimensions was also studied. Lesion detectability and clarity was assessed by four observers. The possibility of extending dose reduction below current dose levels (D ref ) was assessed from comparison of doses that produced statistically significant differences in image quality from D ref . Results: Results show that, with the exception of entrance doses and beam transmission through the diaphragm (P > 0.05), differences in OD and beam transmission between patients and phantom were statistically significant (P ref produced significant changes in both clarity and detectability. Conclusion: Within limits posed by the observed differences, the phantom can be applied to image quality studies in diagnostic radiology.

  9. Conceptus radiation dose and risk from chest screen-film radiography

    International Nuclear Information System (INIS)

    Damilakis, John; Perisinakis, Kostas; Dimovasili, Evangelia; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Varveris, Haralambos

    2003-01-01

    The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d a ) was estimated for 51 women of childbearing age from chest CT examinations. The value of d a was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10 -3 mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d a estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is no need for

  10. Conceptus radiation dose and risk from chest screen-film radiography.

    Science.gov (United States)

    Damilakis, John; Perisinakis, Kostas; Prassopoulos, Panos; Dimovasili, Evangelia; Varveris, Haralambos; Gourtsoyiannis, Nicholas

    2003-02-01

    The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d(a)) was estimated for 51 women of childbearing age from chest CT examinations. The value of d(a) was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10(-3) mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d(a) estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is no need for

  11. Conceptus radiation dose and risk from chest screen-film radiography

    Energy Technology Data Exchange (ETDEWEB)

    Damilakis, John; Perisinakis, Kostas; Dimovasili, Evangelia [Department of Medical Physics, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece); Prassopoulos, Panos; Gourtsoyiannis, Nicholas [Department of Radiology, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece); Varveris, Haralambos [Department of Radiotherapy, University of Crete, Faculty of Medicine, P.O. Box 1393, 714 09 Iraklion, Crete (Greece)

    2003-02-01

    The objectives of the present study were to (a) estimate the conceptus radiation dose and risks for pregnant women undergoing posteroanterior and anteroposterior (AP) chest radiographs, (b) study the conceptus dose as a function of chest thickness of the patient undergoing chest radiograph, and (c) investigate the possibility of a conceptus to receive a dose of more than 10 mGy, the level above which specific measurements of conceptus doses may be necessary. Thermoluminescent dosimeters were used for dose measurements in anthropomorphic phantoms simulating pregnancy at the three trimesters of gestation. The effect of chest thickness on conceptus dose and risk was studied by adding slabs of lucite on the anterior and posterior surface of the phantom chest. The conceptus risk for radiation-induced childhood fatal cancer and hereditary effects was calculated based on appropriate risk factors. The average AP chest dimension (d{sub a}) was estimated for 51 women of childbearing age from chest CT examinations. The value of d{sub a} was estimated to be 22.3 cm (17.4-27.2 cm). The calculated maximum conceptus dose was 107 x 10{sup -3} mGy for AP chest radiographs performed during the third trimester of pregnancy with maternal chest thickness of 27.2 cm. This calculation was based on dose data obtained from measurements in the phantoms and d{sub a} estimated from the patient group. The corresponding average excess of childhood cancer was 10.7 per million patients. The risk for hereditary effects was 1.1 per million births. Radiation dose for a conceptus increases exponentially as chest thickness increases. The conceptus dose at the third trimester is higher than that of the second and first trimesters. The results of the current study suggest that chest radiographs carried out in women at any time during gestation will result in a negligible increase in risk of radiation-induced harmful effects to the unborn child. After a properly performed maternal chest X-ray, there is

  12. Radiology of pulmonary disease. Chest radiography, computed tomography, and gallium scanning

    International Nuclear Information System (INIS)

    Golden, J.A.; Sollitto, R.A.

    1988-01-01

    A review of the radiologic manifestations of AIDS pulmonary diseases, with an emphasis on the utility of gallium scanning in the context of the normal or equivocal chest x-ray, is presented.99 references

  13. How Often is Chest Radiography Ordered for Patients with Pediatric Asthma?

    Directory of Open Access Journals (Sweden)

    Serap Özmen

    2017-08-01

    Full Text Available Objective: Although many children with asthma can be diagnosed clinically, chest radiographs are routinely requested in asthma attacks. The aim of this study is to determine how often chest radiographs are requested and the factors affecting these requests in pediatric patients with asthma. Methods: This cross-sectional study was performed by studying the electronic radiographic records of pediatric patients with asthma who were referred to our Pediatric Allergy and Immunology Department over a six-month period. A questionnaire was designed to obtain further information from the parents of the patients. Results: The records of 100 children with bronchial asthma, aged 21 to 192 months, were evaluated. The average number of chest radiographs was 3.9±3.8 (between 1-30. Fifty-one percent of the children underwent three or more chest radiographs. There was a positive correlation between the number of chest X-rays before asthma diagnosis and the frequency of antibiotic usage (r=0.222, p=0.026. An inverse correlation was found between the number of chest radiographs and the patients’ ages and the age at which asthma was diagnosed (r=−0.335, p=0.001; r=−0.211, p=0.035, respectively. In contrast, there was a positive correlation between the number of chest X-rays and the number of hospital admissions (r=0.205, p=0.040. A positive correlation between the frequency of antibiotic usage and the annual number of hospital admissions was determined (r=0.428, p=0.000. Furthermore, a positive correlation between the frequency of antibiotic usage and the frequency of asthma attacks was observed (r=0.292, p=0.003. Conclusion: The results of our study show that the use of chest radiographs is high in cases of childhood asthma, especially in younger children.

  14. Does a quality assurance training course on chest radiography for radiological technologists improve their performance in Laos?

    Directory of Open Access Journals (Sweden)

    Akihiro Ohkado

    2017-01-01

    Full Text Available Background: It is of critical importance to improve and maintain the quality of chest radiography (CXR to avoid faulty diagnosis of respiratory diseases. The study aims to determine the effectiveness of a training program in improving the quality of CXR among radiological technologists (RTs in Laos. Design: This was a cross-sectional study, conducted through on-site investigation of X-ray facilities, assessment of CXR films in Laos, both before and after a training course in November 2013. Methods: Each RT prospectively selected 6 recent CXR films, taken both before and within approximately 6 months of attending the training course. Consequently, 12 CXR films per RT were supposed to be collected for assessment. The quality of the CXR films was assessed using the “Assessment Sheet for Imaging Quality of Chest Radiography.” Results: Nineteen RTs from 19 facilities at 16 provinces in Laos participated in the training course. Among them, 17 RTs submitted the required set of CXR films (total: 204 films. A wide range of X-ray machine settings had been used as tube voltage ranged from 40 to 130 kV. The assessment of the CXR films indicated that the training was effective in improving the CXR quality regarding contrast (P = 0.005, sharpness (P = 0.004, and the total score on the 6 assessment factors (P = 0.009. Conclusions: The significant improvement in the total score on the 6 assessment factors, in contrast, and in sharpness, strongly suggests that the training course had a positive impact on the quality of CXR among a sample trainees of RTs in Laos.

  15. Comparison of image quality among three x-ray systems for chest radiography: first step in optimisation

    International Nuclear Information System (INIS)

    Nocetti, D.; Ubeda, C.; Calcagno, S.; Acevedo, J.; Pardo, D.

    2015-01-01

    The aim of this study was to compare the performance of three digital X-ray systems [one flat-panel (DR) and two computed radiography (CR)] for chest radiography in terms of the entrance surface air kerma (ESAK) delivered to a polymethyl methacrylate phantom of 20 cm (equivalent to an adult patient) and image quality through of numerical evaluations using a test object (TO). The tube charge applied was ranged from 0.6 to 32 mAs, to a fixed tension of 125 kVp. The DR system presented the highest mean values of ESAK (615.9 μGy) along with the highest signal-to-noise ratio values, whereas CR systems showed a better high-contrast spatial resolution. Differences were statistically significant in both cases regarding the tube charge used. Thus, this parameter should be mainly considered to optimise the radiological protection through exposure settings selected. This survey represents the first effort to achieve optimisation in digital radiology for Chile. (authors)

  16. Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang Tianpeng [Department of Imaging Physics, Digital Imaging Research Laboratory, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009 (United States)

    2011-01-15

    Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full

  17. Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

    International Nuclear Information System (INIS)

    Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang Tianpeng

    2011-01-01

    Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full

  18. The relationship of over density to overexposure each film/screen systems in chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Min; Huo Joon [Korea University, Seoul (Korea, Republic of); Taro, Hayash; Yuji, Ishida; Tatsuya, Sakurai [The Chemotherapeutic Istitute Hospital, Tokyo (Japan)

    1999-06-01

    This study is to calculate the exposed radiation dose using Bit method, NDD calculation method and monogram method without dosimeter. In addition,we can calculate the radiation dose from x-ray film density as a film badge. The authors examined the entrance skin dose from 2 {approx} 3 intercostal chest x-ray film density. We also studied the relationship between film density and equivalent dose in the each screen film system under the different radiation quality and the poor geometry condition of grid ratio. As results, we established the deductive method to define the entrance skin dose from chest x-ray film density. The error range was found in the range -13 percent {approx} +17 percent for between deductive entrance skin dose and the 2 {approx} 3 inter coastal chest x-ray film density to actual detective radiation dose with dosimeter. (author)

  19. Chest radiography in supporting the diagnosis of asthma in children with persistent cough.

    Science.gov (United States)

    Halaby, Claudia; Feuerman, Martin; Barlev, Dan; Pirzada, Melodi

    2014-03-01

    To establish whether chest radiographic findings suggestive of lower airway obstruction (LAO) disease support the diagnosis of asthma in pediatric patients with persistent cough in an outpatient setting. 180 patient charts were reviewed. The patients were children aged 1 to 18 years referred over a 3-year period to a pediatric pulmonary subspecialty clinic for evaluation of cough lasting ≥ 4 weeks. Chest radiographic images obtained after the initial evaluation of 90 patients diagnosed with cough-variant asthma and 90 patients diagnosed with persistent cough from nonasthma origins were compared with radiologic findings of a control group consisting of patients with a positive tuberculin skin test and no respiratory symptoms. Increased peribronchial markings/peribronchial cuffing and hyperinflation were considered radiographically suggestive findings of LAO disease. Children diagnosed with cough-variant asthma at the initial evaluation had higher rates of chest radiographic findings suggestive of LAO disease (30.00%) than children with persistent cough from other causes (17.80%) or those with a positive tuberculin skin test and no respiratory symptoms (8.16%) (overall P value = 0.0063). They also had higher rates of spirometry abnormalities suggestive of an LAO defect. Children with chest radiographic findings suggestive of LAO disease were found to be younger than those with normal chest radiographic findings (5.0 ± 2.7 years vs 8.6 ± 4.7 years; P < 0.0001). This study suggests that chest radiographic findings indicative of an LAO in correlation with the clinical presentation can support the diagnostic suspicion of asthma, especially in younger children unable to perform spirometry.

  20. Large-field image intensifiers versus conventional chest radiography: ROC study with simulated interstitial disease

    International Nuclear Information System (INIS)

    Winter, L.H.L.; Chakraborty, D.P.; Waes, P.F.G.M.

    1988-01-01

    Two image intensifier tubes have recently been introduced whose large imaging area makes them suitable for chest imaging (Phillips Pulmodiagnost TLX slit II and Siemens TX 57 large entrance field II). Both modalities present a 10 x 10-cm hard copy image to the radiologist. A receiver operating characteristic (ROC) curve study with simulated interstitial disease was performed to compare the image quality of these image intensifiers with conventional chest images. The relative ranking in terms of decreasing ROC areas was Siemens, conventional, and Philips. Compared with conventional imaging, none of the differences in ROC curve area were statistically significant at the 5% level

  1. Advanced-stage Hodgkin lymphoma: US/chest radiography for detection of relapse in patients in first complete remission--a randomized trial of routine surveillance imaging procedures.

    Science.gov (United States)

    Picardi, Marco; Pugliese, Novella; Cirillo, Michele; Zeppa, Pio; Cozzolino, Imma; Ciancia, Giuseppe; Pettinato, Guido; Salvatore, Claudia; Quintarelli, Concetta; Pane, Fabrizio

    2014-07-01

    To compare the use of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) with the use of a combination of ultrasonography (US) and chest radiography for systematic follow-up of patients with high-risk Hodgkin lymphoma. Institutional review board approval and informed consent were obtained. In a single center between January 2001 and December 2009, patients with advanced-stage Hodgkin lymphoma who had responded completely to first-line treatment were randomly assigned (1:1) to follow-up with either PET/CT or US/chest radiography. Follow-up included clinical and imaging procedures at 4, 8, 12, 16, 20, 24, 30, 36, 48, 60, 84, and 108 months after treatment discontinuation. When clinical and/or imaging results were positive, recurrence was confirmed histologically. The primary endpoint was to compare the sensitivity of the two follow-up imaging approaches. Secondary endpoints were their specificity, positive and negative predictive values, time to recurrence detection, radiation risks, and costs. A total of 300 patients were randomized into the two arms. The study was closed after a median follow-up time of 60 months, with a relapse rate of 27%. Sensitivity for detection of Hodgkin lymphoma was similar for the two follow-up approaches. All of the relapses (40 of 40) were identified with FDG PET/CT (100%) and 39 of 40 relapses were identified with US/chest radiography (97.5%; P = .0001 for the equivalence test). US/chest radiography showed significantly higher specificity and positive predictive value than did PET/CT (96% [106 of 110] vs 86% [95 of 110], respectively; P = .02; and 91% [39 of 43] vs 73% [40 of 55], respectively; P = .01). Exposure to ionizing radiation was estimated to be 14.5 mSv for one PET/CT examination versus 0.1 mSv for one chest radiographic examination. Estimated cost per relapse diagnosed with routine PET/CT was 10-fold higher compared with that diagnosed with routine US/chest radiography. US and

  2. Survey of the Satisfaction and Dissatisfaction of Referring Physicians Concerning the Radiologic Report of Plain Radiography Except for Chest Plain Radiography

    International Nuclear Information System (INIS)

    Moon, Soon Young; Park, Noh Hyuck; Kim, Mi Sung; Park, Chan Sub; Park, Ji Yeon; Park, Hee Jin; Kim, Sam Soo; Jeon, Hyun Jun

    2011-01-01

    To assess the satisfaction, attitude, dissatisfaction and general opinion of radiologic reports on the plain radiography, except for chest plain radiographs. A questionnaire was distributed to the 63 physicians of our hospital. The questionnaire aimed to investigate physician's general attitude, dissatisfaction and opinions. The responses elicited, as well as discrepancies among residents, staff, medical clinicians and surgical clinicians were assessed. Chi-square and t-tests were used to determine the value of the data. The mean rate of satisfaction for the reading report by medical clinicians (64%) was higher than surgical clinicians (25%) (p < 0.001). The mean satisfaction score was 3.1 (2.8-3.61). The main cause for dissatisfaction was the absence of reports when they were needed, especially for residents. The medical clinician's dependence on radiologic reports was higher than that of the surgical clinicians. The satisfaction score was in the middle range and the main cause of dissatisfaction was absence of the reports when they were needed.

  3. Performance evaluation of image denoising developed using convolutional denoising autoencoders in chest radiography

    Science.gov (United States)

    Lee, Donghoon; Choi, Sunghoon; Kim, Hee-Joung

    2018-03-01

    When processing medical images, image denoising is an important pre-processing step. Various image denoising algorithms have been developed in the past few decades. Recently, image denoising using the deep learning method has shown excellent performance compared to conventional image denoising algorithms. In this study, we introduce an image denoising technique based on a convolutional denoising autoencoder (CDAE) and evaluate clinical applications by comparing existing image denoising algorithms. We train the proposed CDAE model using 3000 chest radiograms training data. To evaluate the performance of the developed CDAE model, we compare it with conventional denoising algorithms including median filter, total variation (TV) minimization, and non-local mean (NLM) algorithms. Furthermore, to verify the clinical effectiveness of the developed denoising model with CDAE, we investigate the performance of the developed denoising algorithm on chest radiograms acquired from real patients. The results demonstrate that the proposed denoising algorithm developed using CDAE achieves a superior noise-reduction effect in chest radiograms compared to TV minimization and NLM algorithms, which are state-of-the-art algorithms for image noise reduction. For example, the peak signal-to-noise ratio and structure similarity index measure of CDAE were at least 10% higher compared to conventional denoising algorithms. In conclusion, the image denoising algorithm developed using CDAE effectively eliminated noise without loss of information on anatomical structures in chest radiograms. It is expected that the proposed denoising algorithm developed using CDAE will be effective for medical images with microscopic anatomical structures, such as terminal bronchioles.

  4. Comparison of Computed Tomography and Chest Radiography in the Detection of Rib Fractures in Abused Infants

    Science.gov (United States)

    Wootton-Gorges, Sandra L.; Stein-Wexler, Rebecca; Walton, John W.; Rosas, Angela J.; Coulter, Kevin P.; Rogers, Kristen K.

    2008-01-01

    Purpose: Chest radiographs (CXR) are the standard method for evaluating rib fractures in abused infants. Computed tomography (CT) is a sensitive method to detect rib fractures. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants. Methods: This retrospective study included all 12 abused infants…

  5. Two K versus 4 K storage phosphor chest radiography: detection performance and image quality

    NARCIS (Netherlands)

    Koelblinger, Claus; Prokop, Mathias; Weber, Michael; Sailer, Johannes; Cartes-Zumelzu, Fabiola; Schaefer-Prokop, Cornelia

    2007-01-01

    The purpose of this study was to evaluate the effect of matrix size (4-K versus 2-K) in digital storage phosphor chest radiographs on image quality and on the detection of CT-proven thoracic abnormalities. In 85 patients who underwent a CT of the thorax, we obtained two additional posteroanterior

  6. Improved detection of focal pneumonia by chest radiography with bone suppression imaging

    International Nuclear Information System (INIS)

    Li, Feng; Engelmann, Roger; Pesce, Lorenzo; Armato, Samuel G.; MacMahon, Heber

    2012-01-01

    To evaluate radiologists' ability to detect focal pneumonia by use of standard chest radiographs alone compared with standard plus bone-suppressed chest radiographs. Standard chest radiographs in 36 patients with 46 focal airspace opacities due to pneumonia (10 patients had bilateral opacities) and 20 patients without focal opacities were included in an observer study. A bone suppression image processing system was applied to the 56 radiographs to create corresponding bone suppression images. In the observer study, eight observers, including six attending radiologists and two radiology residents, indicated their confidence level regarding the presence of a focal opacity compatible with pneumonia for each lung, first by use of standard images, then with the addition of bone suppression images. Receiver operating characteristic (ROC) analysis was used to evaluate the observers' performance. The mean value of the area under the ROC curve (AUC) for eight observers was significantly improved from 0.844 with use of standard images alone to 0.880 with standard plus bone suppression images (P < 0.001) based on 46 positive lungs and 66 negative lungs. Use of bone suppression images improved radiologists' performance for detection of focal pneumonia on chest radiographs. (orig.)

  7. Improved detection of focal pneumonia by chest radiography with bone suppression imaging

    Energy Technology Data Exchange (ETDEWEB)

    Li, Feng; Engelmann, Roger; Pesce, Lorenzo; Armato, Samuel G.; MacMahon, Heber [University of Chicago, Department of Radiology, MC-2026, Chicago, IL (United States)

    2012-12-15

    To evaluate radiologists' ability to detect focal pneumonia by use of standard chest radiographs alone compared with standard plus bone-suppressed chest radiographs. Standard chest radiographs in 36 patients with 46 focal airspace opacities due to pneumonia (10 patients had bilateral opacities) and 20 patients without focal opacities were included in an observer study. A bone suppression image processing system was applied to the 56 radiographs to create corresponding bone suppression images. In the observer study, eight observers, including six attending radiologists and two radiology residents, indicated their confidence level regarding the presence of a focal opacity compatible with pneumonia for each lung, first by use of standard images, then with the addition of bone suppression images. Receiver operating characteristic (ROC) analysis was used to evaluate the observers' performance. The mean value of the area under the ROC curve (AUC) for eight observers was significantly improved from 0.844 with use of standard images alone to 0.880 with standard plus bone suppression images (P < 0.001) based on 46 positive lungs and 66 negative lungs. Use of bone suppression images improved radiologists' performance for detection of focal pneumonia on chest radiographs. (orig.)

  8. The use of bedside chest radiography at a university hospital. Data on a two-week period

    International Nuclear Information System (INIS)

    Delnevo, Alessandra; Tritella, Stefania; Carbonaro, Luca Alessandro; Bobrechova, Oxana; Di Leo, Giovanni; Sardanelli, Francesco

    2012-01-01

    Objective: To evaluate the requests for bedside chest radiography (BCR) by clinicians. Materials and methods: After IRB approval, we retrieved the patients’ clinical records for demographics, unit, and duration for recovery in a two weeks period. For each BCR, exposure data and the reason for BCR were registered. The BCR results were categorized as one or more of the followings: negative, regular/irregular device position, known finding(s) unmodified/modified in respect with the previous BCR, new expected finding(s) (pleural effusion, low ventilation), or new unexpected findings (pulmonary edema, pneumothorax). As a utility indicator of BCR, we considered the rate of chest CT performed in these patients during the study period and the following week. We have estimated the effective radiation dose. Results: A total of 337 BCRs (126 patients) entered the analysis, 74% of them being performed in post-surgery intensive care unit. Seventy-3 patients (58%) performed 1 or 2 BCRs, 53 (42%) 3 or more BCRs with a maximum of 13 BCRs performed on a newborn. The mean total effective dose was 0.2 mSv/patient (maximum 1 mSv). In post-surgery intensive care unit the mean daily BCR rate was 0.8/day (maximum 2/day). On 337 BCR requests, 49% showed no motivations at all, 42% reported the word “check” and in 9% a well-defined clinical query was specified. The rate of incorrect catheter position and new unexpected findings was 4%. One chest CT have been requested. Conclusion: BCR is often requested as a routine examination with a little rate of unexpected findings.

  9. Application of off-line image processing for optimization in chest computed radiography using a low cost system.

    Science.gov (United States)

    Muhogora, Wilbroad E; Msaki, Peter; Padovani, Renato

    2015-03-08

     The objective of this study was to improve the visibility of anatomical details by applying off-line postimage processing in chest computed radiography (CR). Four spatial domain-based external image processing techniques were developed by using MATLAB software version 7.0.0.19920 (R14) and image processing tools. The developed techniques were implemented to sample images and their visual appearances confirmed by two consultant radiologists to be clinically adequate. The techniques were then applied to 200 chest clinical images and randomized with other 100 images previously processed online. These 300 images were presented to three experienced radiologists for image quality assessment using standard quality criteria. The mean and ranges of the average scores for three radiologists were characterized for each of the developed technique and imaging system. The Mann-Whitney U-test was used to test the difference of details visibility between the images processed using each of the developed techniques and the corresponding images processed using default algorithms. The results show that the visibility of anatomical features improved significantly (0.005 ≤ p ≤ 0.02) with combinations of intensity values adjustment and/or spatial linear filtering techniques for images acquired using 60 ≤ kVp ≤ 70. However, there was no improvement for images acquired using 102 ≤ kVp ≤ 107 (0.127 ≤ p ≤ 0.48). In conclusion, the use of external image processing for optimization can be effective in chest CR, but should be implemented in consultations with the radiologists.

  10. The impact of an early-morning radiologist work shift on the timeliness of communicating urgent imaging findings on portable chest radiography.

    Science.gov (United States)

    Kaewlai, Rathachai; Greene, Reginald E; Asrani, Ashwin V; Abujudeh, Hani H

    2010-09-01

    The aim of this study was to assess the potential impact of staggered radiologist work shifts on the timeliness of communicating urgent imaging findings that are detected on portable overnight chest radiography of hospitalized patients. The authors conducted a retrospective study that compared the interval between the acquisition and communication of urgent findings on portable overnight critical care chest radiography detected by an early-morning shift for radiologists (3 am to 11 am) with historical experience with a standard daytime shift (8 am to 5 pm) in the detection and communication of urgent findings in a similar patient population a year earlier. During a 4-month period, 6,448 portable chest radiographic studies were interpreted on the early-morning radiologist shift. Urgent findings requiring immediate communication were detected in 308 (4.8%) studies. The early-morning shift of radiologists, on average, communicated these findings 2 hours earlier compared with the historical control group (P chest radiography of hospitalized patients. Published by Elsevier Inc.

  11. Receiver operating characteristic analysis of chest radiographs with computed radiography and conventional analog films

    International Nuclear Information System (INIS)

    Morioka, C.; Brown, K.; Dalter, S.; Milos, M.J.; Huang, H.K.; Kangarloo, H.; Boechat, I.M.; Batra, P.

    1988-01-01

    Receiver operating characteristic is used to compare the image quality of films obtained digitally using computed radiography (CR) and conventionally using analog film following fluoroscopic examination. Twenty-four cases, some with a solitary noncalcified nodule and/or pneumothorax, were collected. Ten radiologists have been tested viewing analog and CR digital films separately. Preliminary results indicate that there is no significant difference in the ability to detect either a pneumothorax or a solitary noncalcified nodule when comparing CR digital film with conventional analog film. A comparison of the CR digital image displayed on a 2,048-line monitor against analog and CR digital film is in progress

  12. Pacemakers and implantable cardioverter defibrillators, unknown to chest radiography: Review, complications and systematic reading

    International Nuclear Information System (INIS)

    Alandete Germán, Salvador Pascual; Isarria Vidal, Santiago; Domingo Montañana, María Luisa; De la vía Oraá, Esperanza; Vilar Samper, José

    2015-01-01

    Highlights: •Radiologists have an important function in the evaluation of these devices. •We revise their radiological appearances and possible complications. •The knowledge in normal aspects and complications is important for radiologist. •To ensure an accurate reading of the chest x-ray, we present a systematic approach. -- Abstract: Chest X-ray is the imaging technique of choice for an initial study of pacemakers and implantable cardio-defibrillators (ICD). Radiologists have an important role in the evaluation of its initial placement and in the assessment during its follow-up. For this reason, it is necessary to know not only the different existing devices and its components but also the reasons of malfunction or possible complications. The purpose of this article is to do a systematic review of the different types of pacemakers and ICD. We review their usual radiological appearances, the possible complications which might take place and its causes of malfunctioning

  13. Effect of data compression on diagnostic accuracy in digital hand and chest radiography

    Science.gov (United States)

    Sayre, James W.; Aberle, Denise R.; Boechat, Maria I.; Hall, Theodore R.; Huang, H. K.; Ho, Bruce K. T.; Kashfian, Payam; Rahbar, Guita

    1992-05-01

    Image compression is essential to handle a large volume of digital images including CT, MR, CR, and digitized films in a digital radiology operation. The full-frame bit allocation using the cosine transform technique developed during the last few years has been proven to be an excellent irreversible image compression method. This paper describes the effect of using the hardware compression module on diagnostic accuracy in hand radiographs with subperiosteal resorption and chest radiographs with interstitial disease. Receiver operating characteristic analysis using 71 hand radiographs and 52 chest radiographs with five observers each demonstrates that there is no statistical significant difference in diagnostic accuracy between the original films and the compressed images with a compression ratio as high as 20:1.

  14. Computer-aided detection as a decision assistant in chest radiography

    Science.gov (United States)

    Samulski, Maurice R. M.; Snoeren, Peter R.; Platel, Bram; van Ginneken, Bram; Hogeweg, Laurens; Schaefer-Prokop, Cornelia; Karssemeijer, Nico

    2011-03-01

    Background. Contrary to what may be expected, finding abnormalities in complex images like pulmonary nodules in chest radiographs is not dominated by time-consuming search strategies but by an almost immediate global interpretation. This was already known in the nineteen-seventies from experiments with briefly flashed chest radiographs. Later on, experiments with eye-trackers showed that abnormalities attracted the attention quite fast but often without further reader actions. Prolonging one's search seldom leads to newly found abnormalities and may even increase the chance of errors. The problem of reading chest radiographs is therefore not dominated by finding the abnormalities, but by interpreting them. Hypothesis. This suggests that readers could benefit from computer-aided detection (CAD) systems not so much by their ability to prompt potential abnormalities, but more from their ability to 'interpret' the potential abnormalities. In this paper, this hypothesis was investigated by an observer experiment. Experiment. In one condition, the traditional CAD condition, the most suspicious CAD locations were shown to the subjects, without telling them the levels of suspiciousness according to CAD. In the other condition, interactive CAD condition, levels of suspiciousness were given, but only when readers requested them at specified locations. These two conditions focus on decreasing search errors and decision errors, respectively. Results of reading without CAD were also recorded. Six subjects, all non-radiologists, read 223 chest radiographs in both conditions. CAD results were obtained from the OnGuard 5.0 system developed by Riverain Medical (Miamisburg, Ohio). Results. The observer data were analyzed by Location Response Operating Characteristic analysis (LROC). It was found that: 1) With the aid of CAD, the performance is significantly better than without CAD; 2) The performance with interactive CAD is significantly better than with traditional CAD at low false

  15. Two K versus 4 K storage phosphor chest radiography: detection performance and image quality

    International Nuclear Information System (INIS)

    Koelblinger, Claus; Weber, Michael; Sailer, Johannes; Cartes-Zumelzu, Fabiola; Prokop, Mathias; Schaefer-Prokop, Cornelia

    2007-01-01

    The purpose of this study was to evaluate the effect of matrix size (4-K versus 2-K) in digital storage phosphor chest radiographs on image quality and on the detection of CT-proven thoracic abnormalities. In 85 patients who underwent a CT of the thorax, we obtained two additional posteroanterior storage phosphor chest radiographs, one with a matrix size of 3,520 x 4,280 (=4-K) and the other with a matrix size of 1,760 x 2,140 (=2-K). Acquisition, processing and presentation parameters were identical for all radiographs. Two radiologists evaluated the presence of mediastinal, pleural, and pulmonary abnormalities on hard copies of the radiographs, applying ROC analysis. In addition, four radiologists were asked to subjectively rank differences in image quality and to assess the demarcation of anatomic landmarks comparing the images in a blinded side-by-side manner. These data were analyzed using a two-sided binomial test with a significance level of P<0.05. Both tests, the ROC analysis of the detection performance and the binomial test of the subjective quality ratings, did not reveal significant differences between the two matrix sizes. Compared to 2-K radiographs, 4-K storage phosphor chest radiographs do not provide superior detection performance or image quality when evaluated in identical hard copy formats. (orig.)

  16. Digital chest radiography: an update on modern technology, dose containment and control of image quality

    International Nuclear Information System (INIS)

    Schaefer-Prokop, Cornelia; Venema, Henk W.; Neitzel, Ulrich; Uffmann, Martin; Prokop, Mathias

    2008-01-01

    The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions. This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing. It explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose. It also provides an overview over the multitude of studies conducted in recent years to evaluate the options of these new developments to realize the principle of ALARA. The focus of the review is hereby on adult applications, the relationship between dose and image quality and the differences between the various detector systems. (orig.)

  17. A comparative study of collimation in bedside chest radiography for preterm infants in two teaching hospitals

    International Nuclear Information System (INIS)

    Stollfuss, J.; Schneider, K.; Krüger-Stollfuss, I.

    2015-01-01

    •Potential factors influencing non-optimal image collimation in the setting of bedside chest X-ray in preterm infants were investigated.•A comparable rate of optimal images was observed in two hospitals.•Size, weight or disease severity had no influence on collimation quality.•Unrelated to the years of experience a large variation of the technician in correct collimation was noted (18–86%).•Individualized quality control and education is necessary. Potential factors influencing non-optimal image collimation in the setting of bedside chest X-ray in preterm infants were investigated. A comparable rate of optimal images was observed in two hospitals. Size, weight or disease severity had no influence on collimation quality. Unrelated to the years of experience a large variation of the technician in correct collimation was noted (18–86%). Individualized quality control and education is necessary. Unnecessary exposure of the abdomen, arms or head may lead to a substantial increase of the radiation dose in portable chest X-rays on the neonatal intensive care unit. The objective was to identify potential factors influencing inappropriate exposure of non-thoracic structures in two teaching hospitals. The study analysed 200 consecutive digital chest radiographs in 20 preterm neonates (mean gestation 25 ± 1 weeks). Demographical data, tube settings and exposure parameters were recorded. To grade the collimation, we used a scoring system with a maximum of 12 exposed non-thoracic structures. Length of gestation, age, the radiographer, years of experience in performing X-rays and the number of in situ catheters or lines, were correlated with collimation quality. There was no significant difference between the rates of optimal images obtained in the two hospitals (0.32 vs 0.39, n.s.). Scores showed that most suboptimal images had only mildly reduced image quality (1.40 ± 1.38 vs 1.20 ± 1.43, n.s.). Length of gestation or presence of surgical drains, catheters and

  18. Low Yield of Chest Radiography in General Inpatients and Outpatients with "Positive PPD" Results in a Country with Low Prevalence of TB.

    Science.gov (United States)

    Eisenberg, Ronald L; Heidinger, Benedikt H

    2017-07-01

    The purpose of this study was to assess the frequency and spectrum of abnormalities on routine screening chest radiographs among inpatients and outpatients with "positive purified protein derivative (PPD)" in a large tertiary care academic medical center in a country with low prevalence of tuberculosis (TB). The reports of all chest radiographs of general inpatients and outpatients referred for positive PPD (2010-2014) were evaluated for the frequency of evidence of active or latent TB and the spectrum of imaging findings. The results of additional chest radiographs and computed tomography scans were recorded, as were additional relevant clinical histories and symptoms. Of the 2518 patients who underwent chest radiography for positive PPD, the radiographs were normal in 91.3%. The vast majority of the abnormal radiographs demonstrated findings consistent with old tuberculous disease. There were three cases (0.1%) of active TB, all of which were either recent immigrants from an endemic area or had other relevant histories or clinical symptoms suggestive of the disease. Universal chest radiography in general inpatient and outpatient populations referred for positive PPD is of low yield for detecting active disease in a country with low prevalence of TB. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  19. Study of two novel large-field-of-view image intensifiers versus conventional chest radiography with use of FROC methods and simulated pulmonary nodules

    International Nuclear Information System (INIS)

    Winter, L.H.L.; Chakraborty, D.P.; Van Waes, P.F.G.M.; Puylaert, C.B.A.J.

    1989-01-01

    Two novel large-field-of-view image intensifier (LFOV 1.1) tubes have been introduced whose image area makes them suitable for chest imaging. Both modalities present a 100-mm hard-copy image to the radiologist. A pulmonary nodule performance experiment was done to compare the diagnostic accuracy of these tubes with conventional full-size chest images. The data were analyzed with the maximum-likelihood FROCFIT program. The relative ranking in terms of decreasing A1 values was TLX, Siemens 43-cm mode, conventional radiography, and Siemens 57-cm mode

  20. The value of digital tomosynthesis of the chest as a problem-solving tool for suspected pulmonary nodules and hilar lesions detected on chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Galea, Angela, E-mail: galeaangie@gmail.com [Peninsula Radiology Academy, William Prance Road, Plymouth PL65WR (United Kingdom); Dubbins, Paul, E-mail: Paul.dubbins@nhs.net [Plymouth Hospital NHS Trust, Plymouth PL68DH (United Kingdom); Riordan, Richard, E-mail: richardriordan@nhs.net [Plymouth Hospital NHS Trust, Plymouth PL68DH (United Kingdom); Adlan, Tarig, E-mail: tarig.adlan@nhs.net [Plymouth Hospital NHS Trust, Plymouth PL68DH (United Kingdom); Roobottom, Carl, E-mail: carl.roobotoom@nhs.net [Plymouth Hospital NHS Trust, Plymouth PL68DH (United Kingdom); Gay, David, E-mail: davegay@nhs.net [Plymouth Hospital NHS Trust, Plymouth PL68DH (United Kingdom)

    2015-05-15

    Graphical abstract: When compared to CXR, DTS has: • Superior resolution • Better assessment of location in the AP dimension (better at locating a pleural or intrapulmonary lesion) • Better characterisation (better at distinguishing between calcified plaque and soft tissue) • Removes composite artefact caused by overlying anatomical structures (such as the ribs or pulmonary vessels) DTS has improved sensitivity, specificity and accuracy when compared to CXR. - Highlights: • DTS is a type of limited angle tomography. Sixty coronal reconstructed images of the chest are produced that combine the superior resolution of radiography with the tomographic benefits of computed tomography. • The sensitivity for detecting a suspected lung lesions is 0.65 with CXR and 0.91 for DTS. • The high specificity of DTS (1) and the high negative predictive value (0.94) are similar to CT and suggest that if the DTS is normal patients do not need further assessment with CT with significant potential dose savings. • 50% of suspected lesions were resolved with CXR, this improved to 96% with DTS. - Abstract: Objectives: To assess the capability of digital tomosynthesis (DTS) of the chest compared to a postero-anterior (PA) and lateral chest radiograph (CXR) in the diagnosis of suspected but unconfirmed pulmonary nodules and hilar lesions detected on a CXR. Computed tomography (CT) was used as the reference standard. Materials and method: 78 patients with suspected non-calcified pulmonary nodules or hilar lesions on their CXR were included in the study. Two radiologists, blinded to the history and CT, prospectively analysed the CXR (PA and lateral) and the DTS images using a picture archiving and communication workstation and were asked to designate one of two outcomes: true intrapulmonary lesion or false intrapulmonary lesion. A CT of the chest performed within 4 weeks of the CXR was used as the reference standard. Inter-observer agreement and time to report the modalities

  1. The value of digital tomosynthesis of the chest as a problem-solving tool for suspected pulmonary nodules and hilar lesions detected on chest radiography

    International Nuclear Information System (INIS)

    Galea, Angela; Dubbins, Paul; Riordan, Richard; Adlan, Tarig; Roobottom, Carl; Gay, David

    2015-01-01

    Graphical abstract: When compared to CXR, DTS has: • Superior resolution • Better assessment of location in the AP dimension (better at locating a pleural or intrapulmonary lesion) • Better characterisation (better at distinguishing between calcified plaque and soft tissue) • Removes composite artefact caused by overlying anatomical structures (such as the ribs or pulmonary vessels) DTS has improved sensitivity, specificity and accuracy when compared to CXR. - Highlights: • DTS is a type of limited angle tomography. Sixty coronal reconstructed images of the chest are produced that combine the superior resolution of radiography with the tomographic benefits of computed tomography. • The sensitivity for detecting a suspected lung lesions is 0.65 with CXR and 0.91 for DTS. • The high specificity of DTS (1) and the high negative predictive value (0.94) are similar to CT and suggest that if the DTS is normal patients do not need further assessment with CT with significant potential dose savings. • 50% of suspected lesions were resolved with CXR, this improved to 96% with DTS. - Abstract: Objectives: To assess the capability of digital tomosynthesis (DTS) of the chest compared to a postero-anterior (PA) and lateral chest radiograph (CXR) in the diagnosis of suspected but unconfirmed pulmonary nodules and hilar lesions detected on a CXR. Computed tomography (CT) was used as the reference standard. Materials and method: 78 patients with suspected non-calcified pulmonary nodules or hilar lesions on their CXR were included in the study. Two radiologists, blinded to the history and CT, prospectively analysed the CXR (PA and lateral) and the DTS images using a picture archiving and communication workstation and were asked to designate one of two outcomes: true intrapulmonary lesion or false intrapulmonary lesion. A CT of the chest performed within 4 weeks of the CXR was used as the reference standard. Inter-observer agreement and time to report the modalities

  2. Computerized Classification of Pneumoconiosis on Digital Chest Radiography Artificial Neural Network with Three Stages.

    Science.gov (United States)

    Okumura, Eiichiro; Kawashita, Ikuo; Ishida, Takayuki

    2017-08-01

    It is difficult for radiologists to classify pneumoconiosis from category 0 to category 3 on chest radiographs. Therefore, we have developed a computer-aided diagnosis (CAD) system based on a three-stage artificial neural network (ANN) method for classification based on four texture features. The image database consists of 36 chest radiographs classified as category 0 to category 3. Regions of interest (ROIs) with a matrix size of 32 × 32 were selected from chest radiographs. We obtained a gray-level histogram, histogram of gray-level difference, gray-level run-length matrix (GLRLM) feature image, and gray-level co-occurrence matrix (GLCOM) feature image in each ROI. For ROI-based classification, the first ANN was trained with each texture feature. Next, the second ANN was trained with output patterns obtained from the first ANN. Finally, we obtained a case-based classification for distinguishing among four categories with the third ANN method. We determined the performance of the third ANN by receiver operating characteristic (ROC) analysis. The areas under the ROC curve (AUC) of the highest category (severe pneumoconiosis) case and the lowest category (early pneumoconiosis) case were 0.89 ± 0.09 and 0.84 ± 0.12, respectively. The three-stage ANN with four texture features showed the highest performance for classification among the four categories. Our CAD system would be useful for assisting radiologists in classification of pneumoconiosis from category 0 to category 3.

  3. Aspects of radiation protection during chest X-radiography; Strahlenhygienische Aspekte bei der Roentgenuntersuchung des Thorax

    Energy Technology Data Exchange (ETDEWEB)

    Seidenbusch, M.C.; Schneider, K. [Dr. von Haunersches Kinderspital, Klinikum der Universitaet Muenchen, Institut fuer Klinische Radiologie - Kinderradiologie, Muenchen (Germany)

    2015-07-15

    Radiation safety in conventional X-ray diagnostics is based on the concepts of justification, optimization of an X-ray examination and limitation of the radiation exposure achieved during the examination. Optimization of an X-ray examination has to be considered as a multimodal process in which all technical components of the X-ray equipment have to be adapted to each other and also have to be adapted to the anthropometric characteristics of patients and the clinical indications. In this article the technical components of a conventional pediatric chest X-radiograph are presented, and recommendations for optimizing chest X-rays in children are provided. The following measures are of prime importance: correct x-ray beam limitation, using the posteroanterior projection when possible and not using anti-scatter grids in children under approximately 8 years old. In pediatric radiology chest x-rays that are taken not at the peak of inspiration can also be of some diagnostic significance. Optimization of an X-ray examination inevitably results in the limitation of radiation exposure. (orig.) [German] Die Strahlenhygiene in der konventionellen radiologischen Diagnostik basiert auf der Trias Rechtfertigung, Optimierung bzw. Limitierung der Roentgenuntersuchung bzw. Strahlenexposition. Die Optimierung einer Roentgenuntersuchung ist als multimodaler Prozess aufzufassen, in welchem saemtliche technische Komponenten der Roentgeneinrichtung sowohl miteinander als auch mit den anthropometrischen Eigenschaften des Patienten und der klinischen Fragestellung abzustimmen sind. Im vorliegenden Beitrag werden die technischen Komponenten bei der konventionellen Roentgenuntersuchung des paediatrischen Thorax in ihrer Beziehung zueinander dargestellt und Empfehlungen fuer eine Optimierung der konventionellen Thoraxaufnahme bei Kindern ausgesprochen. Die wichtigsten Massnahmen bestehen in einer korrekten Einblendung, in der Anfertigung der Aufnahmen im posteroanterioren Strahlengang und im

  4. Comparative study of mesothelioma and asbestosis using computed tomography and conventional chest radiography

    International Nuclear Information System (INIS)

    Rabinowitz, T.G.; Efremidis, S.C.; Cohen, B.; Dan, S.; Efremidis, A.; Chahinian, A.P.; Teirstein, A.S.

    1982-01-01

    A comparative study using computed tomography and conventional posteroanterior radiography was performed on 27 patients with mesothelioma and 13 patients with advanced asbestosis. The major pathologic features of both asbestosis and mesothelioma were well demonstrated by both modalities; computed tomography demonstrated the findings more frequently and in greater detail. No distinguishing features could be established based on configuration and size of the lesion. Many pleural plaques associated with advanced asbestosis were large and irregular and resembled those associated with mesothelioma. However, nodular involvement of the pleural fissures, pleural effusion, and ipsilateral volume loss with a fixed mediastinum were features predominating in mesothelioma. Growth determination of the plaques associated with asbestosis may be of minimal value since such plaques also undergo growth due to active inflammatory changes

  5. Chest radiography with a shaped filter has no diagnostic advantage: Demonstration by observer performance tests

    International Nuclear Information System (INIS)

    Guilbeau, J.C.; Mazoyer, B.; Pruvost, P.; Verrey, B.; Grenier, P.

    1987-01-01

    The effectiveness of a shaped filter in improving the detection of mediastinal and retrocardiac abnormalities on 140-kV posteroanterior chest radiographs was measured by observer performance testing. The filtered and unfiltered radiographs of 50 patients were randomly selected from 1,000 radiographs obtained from 500 ambulatory or hospitalized patients and were independently read by five observers. Observer performance in detecting abnormalities in the central area was analyzed by receiver operating characteristic (ROC) techniques. The results indicate that the use of a filter has no significant diagnostic advantage, regardless of type or location of lesions over the mediastinum and the retrocardiac areas

  6. Clinical evaluation of wide-latitude HR-C film for chest radiography

    International Nuclear Information System (INIS)

    Kim, Young Sung; Hwang, Nam Sun; Yeo, Young Bok; Lee, In Ja; Huh, Joon

    1990-01-01

    In application of wide latitude HR-C film to chest x-ray examination, former x-ray diagnosis area is larger and diagnostic information has great deal of promotion. HR-C film is compare to former x-ray film is larger latitude and density level is small, reading is very easily. Especially, high estimate that is in characteristic curve linearity of toe part is good, contrast of low density made good shape and not good describe to overlap is diagnostic information increase mediastinum portion etc

  7. High-resolution computed tomography in silicosis: correlation with chest radiography and pulmonary function tests

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Agnaldo Jose [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Pedro Ernesto Univ. Hospital. Dept. of Respiratory Function]. E-mail: phel.lop@uol.com.br; Mogami, Roberto; Capone, Domenico; Jansen, Jose Manoel [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). School of Medical Sciences; Tessarollo, Bernardo [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Dept. of Radiology and Diagnostic Image; Melo, Pedro Lopes de [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. of Biology

    2008-05-15

    Objective: To correlate tomographic findings with pulmonary function findings, as well as to compare chest X-ray findings with high-resolution computed tomography (HRCT) findings, in patients with silicosis. Methods: A cross-sectional study was conducted in 44 non-smoking patients without a history of tuberculosis. Chest X-ray findings were classified according to the International Labour Organization recommendations. Using a semiquantitative system, the following HRCT findings were measured: the full extent of pulmonary involvement; parenchymal opacities; and emphysema. Spirometry and forced oscillation were performed. Pulmonary volumes were evaluated using the helium dilution method, and diffusing capacity of the lung for carbon monoxide was assessed. Results: Of the 44 patients studied, 41 were male. The mean age was 48.4 years. There were 4 patients who were classified as category 0 based on X-ray findings and as category 1 based on HRCT findings. Using HRCT scans, we identified progressive massive fibrosis in 33 patients, compared with only 23 patients when X-rays were used. Opacity score was found to correlate most closely with airflow, DLCO and compliance. Emphysema score correlated inversely with volume, DLCO and airflow. In this sample of patients presenting a predominance of large opacities (75% of the individuals), the deterioration of pulmonary function was associated with the extent of structural changes. Conclusions: In the early detection of silicosis and the identification of progressive massive fibrosis, HRCT scans are superior to X-rays. (author)

  8. High-resolution computed tomography in silicosis: correlation with chest radiography and pulmonary function tests

    International Nuclear Information System (INIS)

    Lopes, Agnaldo Jose; Mogami, Roberto; Capone, Domenico; Jansen, Jose Manoel; Tessarollo, Bernardo; Melo, Pedro Lopes de

    2008-01-01

    Objective: To correlate tomographic findings with pulmonary function findings, as well as to compare chest X-ray findings with high-resolution computed tomography (HRCT) findings, in patients with silicosis. Methods: A cross-sectional study was conducted in 44 non-smoking patients without a history of tuberculosis. Chest X-ray findings were classified according to the International Labour Organization recommendations. Using a semiquantitative system, the following HRCT findings were measured: the full extent of pulmonary involvement; parenchymal opacities; and emphysema. Spirometry and forced oscillation were performed. Pulmonary volumes were evaluated using the helium dilution method, and diffusing capacity of the lung for carbon monoxide was assessed. Results: Of the 44 patients studied, 41 were male. The mean age was 48.4 years. There were 4 patients who were classified as category 0 based on X-ray findings and as category 1 based on HRCT findings. Using HRCT scans, we identified progressive massive fibrosis in 33 patients, compared with only 23 patients when X-rays were used. Opacity score was found to correlate most closely with airflow, DLCO and compliance. Emphysema score correlated inversely with volume, DLCO and airflow. In this sample of patients presenting a predominance of large opacities (75% of the individuals), the deterioration of pulmonary function was associated with the extent of structural changes. Conclusions: In the early detection of silicosis and the identification of progressive massive fibrosis, HRCT scans are superior to X-rays. (author)

  9. Nodule detection in digital chest radiography: Part of image background acting as pure noise

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Bochud, F. O.; Verdun, F. R.; Maansson, L. G.

    2005-01-01

    There are several factors that influence the radiologist's ability to detect a specific structure/lesion in a radiograph. Three factors that are commonly known to be of major importance are the signal itself, the system noise and the projected anatomy. The aim of this study was to determine to what extent the image background acts as pure noise for the detection of subtle lung nodules in five different regions of the chest. A receiver operating characteristic (ROC) study with five observers was conducted on two different sets of images, clinical chest X-ray images and images with a similar power spectrum as the clinical images but with a random phase spectrum, resulting in an image background containing pure noise. Simulated designer nodules with a full-width-at-fifth-maximum of 10 mm but with varying contrasts were added to the images. As a measure of the part of the image background that acts as pure noise, the ratio between the contrast needed to obtain an area under the ROC curve of 0.80 in the clinical images to that in the random-phase images was used. The ratio ranged from 0.40 (in the lateral pulmonary regions) to 0.83 (in the hilar regions) indicating that there was a large difference between different regions regarding to what extent the image background acted as pure noise; and that in the hilar regions the image background almost completely acted as pure noise for the detection of 10 mm nodules. (authors)

  10. Determinants of early adult respiratory distress syndrome with special reference to chest radiography

    International Nuclear Information System (INIS)

    Wegenius, G.; Modig, J.; Akademiska Sjukhuset, Uppsala

    1985-01-01

    The medical records of 220 consecutive patients with traumatic injuries admitted to the intensive care unit in the years 1974-1982 were scrutinised in an attempt to find radiographic signs and clinical determinants of early adult respiratory distress syndrome (ARDS). All patients included in this study were considered to run a risk of developing ARDS and had 'pure' major fractures in the sense that there were no accompanying severe brain, chest or abdominal injuries. There were no deaths in this series of patients. ARDS developed in 27 patients (12.3%), on an average on the second day of trauma. Chest radiographs of 21 of these patients showed features indicative of ARDS, whereas those of the other 6 patients were normal despite hypoxaemia. In most of the 27 patients the only radiographic manifestation of ARDS was interstitial oedema; only a minority presented with alveolar oedema in addition. In 6 patients no radiographic changes ever occurred. Ventilator treatment with positive end expiratory pressure may have prevented the pulmonary insufficiency from becoming radiographically manifest. The clinical determinants of post-traumatic ARDS were a high fracture index, based on the number and severity of fractures, implying severe trauma, and shock on admission. Fluid overload was not found to be the cause of ARDS. (orig.)

  11. Dose distributions of patients from chest fluoroscopy, upper GI-tract radiography and cinematography in Japan

    International Nuclear Information System (INIS)

    Kusama, T.; Kai, M.; Ohta, K.

    1996-01-01

    The per caput dose from medical exposure in Japan is several times higher than in other developed countries. There are no dose limitations for medical exposure. Then, the appropriate applications of radiation diagnosis/treatments (justification of practices) and the quality control of diagnosis/treatments (optimization of protection) are needed to reduce the doses from medical exposure. It is well documented that patient doses from a X-ray diagnosis are distributed in the broad range. Recently, the IAEA introduced guidance levels for some typical X-ray diagnosis and in vivo nuclear medicines. We carried out the investigation of dose distribution of patients from the X-ray examinations of chest, cardiovascular cinematography and upper GI-tract X-ray examination in order to give the basic information on the quality control of each X-ray diagnosis. These X-ray diagnoses are performed frequently in Japan, and especially chest X-ray examinations are carried out periodically to all population more than 18 years old as legal health check and GI-tract X-ray examinations to the persons more than 35 years old. The cardiovascular cinematography and the upper GI-tract X-ray examination bring higher effective dose for patients. More information is therefore, needed for the reduction and quality control of medical exposure in Japan. (author)

  12. Analysis of the impact of digital tomosynthesis on the radiological investigation of patients with suspected pulmonary lesions on chest radiography

    Energy Technology Data Exchange (ETDEWEB)

    Quaia, Emilio; Baratella, Elisa; Cernic, Stefano; Lorusso, Arianna; Casagrande, Federica; Cioffi, Vincenzo; Cova, Maria Assunta [University of Trieste (Italy), Department of Radiology, Cattinara Hospital, Trieste (Italy)

    2012-09-15

    To assess the impact of digital tomosynthesis (DTS) on the radiological investigation of patients with suspected pulmonary lesions on chest radiography (CXR). Three hundred thirty-nine patients (200 male; age, 71.19 {+-} 11.9 years) with suspected pulmonary lesion(s) on CXR underwent DTS. Two readers prospectively analysed CXR and DTS images, and recorded their diagnostic confidence: 1 or 2 = definite or probable benign lesion or pseudolesion deserving no further diagnostic workup; 3 = indeterminate; 4 or 5 = probable or definite pulmonary lesion deserving further diagnostic workup by computed tomography (CT). Imaging follow-up by CT (n = 76 patients), CXR (n = 256) or histology (n = 7) was the reference standard. DTS resolved doubtful CXR findings in 256/339 (76 %) patients, while 83/339 (24 %) patients proceeded to CT. The mean interpretation time for DTS (mean {+-} SD, 220 {+-} 40 s) was higher (P < 0.05; Wilcoxon test) than for CXR (110 {+-} 30 s), but lower than CT (600 {+-} 150 s). Mean effective dose was 0.06 mSv (range 0.03-0.1 mSv) for CXR, 0.107 mSv (range 0.094-0.12 mSv) for DTS, and 3 mSv (range 2-4 mSv) for CT. DTS avoided the need for CT in about three-quarters of patients with a slight increase in the interpretation time and effective dose compared to CXR. (orig.)

  13. An evaluation of automated chest radiography reading software for tuberculosis screening among public- and private-sector patients.

    Science.gov (United States)

    Rahman, Md Toufiq; Codlin, Andrew J; Rahman, Md Mahfuzur; Nahar, Ayenun; Reja, Mehdi; Islam, Tariqul; Qin, Zhi Zhen; Khan, Md Abdus Shakur; Banu, Sayera; Creswell, Jacob

    2017-05-01

    Computer-aided reading (CAR) of medical images is becoming increasingly common, but few studies exist for CAR in tuberculosis (TB). We designed a prospective study evaluating CAR for chest radiography (CXR) as a triage tool before Xpert MTB/RIF (Xpert).Consecutively enrolled adults in Dhaka, Bangladesh, with TB symptoms received CXR and Xpert. Each image was scored by CAR and graded by a radiologist. We compared CAR with the radiologist for sensitivity and specificity, area under the receiver operating characteristic curve (AUC), and calculated the potential Xpert tests saved.A total of 18 036 individuals were enrolled. TB prevalence by Xpert was 15%. The radiologist graded 49% of CXRs as abnormal, resulting in 91% sensitivity and 58% specificity. At a similar sensitivity, CAR had a lower specificity (41%), saving fewer (36%) Xpert tests. The AUC for CAR was 0.74 (95% CI 0.73-0.75). CAR performance declined with increasing age. The radiologist grading was superior across all sub-analyses.Using CAR can save Xpert tests, but the radiologist's specificity was superior. Differentiated CAR thresholds may be required for different populations. Access to, and costs of, human readers must be considered when deciding to use CAR software. More studies are needed to evaluate CAR using different screening approaches. Copyright ©ERS 2017.

  14. A study on image quality and exposure dose of hard radiation radiography of the chest

    International Nuclear Information System (INIS)

    Hayashi, Taro; Ishida, Yuji; Maeda, Mika; Sakurai, Tatsuya; Kim, Chung Woon; Hwang, Jong Sun

    1991-01-01

    Experiment was conducted on the image quality and exposure dose following replacement of CaWO 4 system screen BH - III and BX - III which have so far been used for high - voltage hard - radiation quality radiography, with rare earth system screen KO750, combined with high contrast film SRH, while additional filter was altered, Cu 0.8 mm + Al 1.4 mm(HVL : AI 8.8 mm), Cu 1.3 mm + AI 1.0mm(HVL: AI 10.6mm) and Cu 1.8mm + AI 1.5mm(HVL: AI 11.4mm). AS a result, visual evaluation did not detect extreme changes in image quality under the respective condition (HVL : Al 8.8 mm ∼ AI 11.4 mm). It was noted, however, that surface exposure dose declined with an increase in the thickness of the additional filter, as it was 18.9 μGy at HVL Al 8.8 mm, 17.5 μGy at Al 10.6 mm and 15.7 μGy at Al 11.4 mm. Considering the limited rating of X-ray equipment and wear of machinery, however, the range of Cu 1.3 mm ∼ l.8 mm + AI 1.0 mm ∼ 1.5 mm(1/16 VL ∼ 1/32 VL) seemed to be a limit

  15. Chest X-Ray

    Medline Plus

    Full Text Available ... about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed x-ray exams and use a very small dose of ... of the inside of the chest. A chest x-ray is used to evaluate the lungs, heart and ...

  16. SARS: a comparative study on the chest radiography of the mortal cases and the cured cases

    International Nuclear Information System (INIS)

    Jiang Songfeng; Liu Jingxin; Chen Bihua; Zhang Lieguang; Yin Chibiao; Zhang Fuchun

    2003-01-01

    Objective: This study is mainly on the radiological findings of the mortal cases of SARS. Methods: The chest X-ray (CXR) findings of 11 mortal cases of SARS were retrospectively studied, and compared with those of the 249 cured cases. Results: The major CXR findings of the mortal cases were: patchy shadows in 10 cases out of 11 (90.90%), frosted glass like change of the lung fields in 9 (81.82%), diffuse lesions in 11 (100%), and involvement of the bilateral lung. There was a statistical difference between the mortal cases and the cured cases on the following 4 manifestations: large shadows, extensive consolidation, frosted glass like change of the lung fields, and diffuse lesions (P<0.01). Conclusion: Large shadows, extensive consolidation, frosted glass like change of the lung fields, diffuse lesions and the bilateral involvement of the lung are the main CXR findings of the mortal cases of SARS. And extensive consolidation and diffuse involvement are strongly indicative. In most of the mortal cases, the latest CXR demonstrated widespread frosted glass like appearance in the lung fields with air bronchogram

  17. Study of distribution dose for chest radiography using the computational model ALDERSON/EGSnrc

    International Nuclear Information System (INIS)

    Muniz, B.C.; Menezes, C.J.M.

    2017-01-01

    Numerical dosimetry uses Computational Exposure Models (MCE) to perform dose studies in situations of radiation exposure without the need for individuals to be exposed. MCEs are essentially composed of a simulator of the radioactive source, a Monte Carlo code, and a phantom of voxels representing the human anatomy. The objective of this work was to perform a study of the dose distribution in the thoracic region in radiographic exams using the MCE ALDERSON / EGSnrc. For that, virtual simulations were performed using Monte Carlo Method techniques to calculate the dose in the simulator of voxels representative of the thoracic region. The results show that most beam energy was deposited in the skeleton for all simulated radiological techniques, while smaller fractions were deposited in the lungs and soft tissue. For example, at 90 kV voltage, 14% of the energy was deposited in the bone medium, while lungs and soft tissue receive only 5 and 3%, respectively. It is concluded that the ALDERSON / EGSnrc MCE can be used for studies of the dose distribution on chest radiographs used in radiodiagnosis practice, thus optimizing dose absorbed in the patient in clinical exams

  18. Pulmonary infections in the late period after allogeneic bone marrow transplantation: chest radiography versus computed tomography

    International Nuclear Information System (INIS)

    Schueller, Gerd; Matzek, Wolfgang; Kalhs, Peter; Schaefer-Prokop, Cornelia

    2005-01-01

    Purpose: To analyze the capabilities of chest roentgenogram (CXR) and computed tomography (CT) in the evaluation of pulmonary infectious disease in the late period (>100 days) after allogeneic bone marrow transplantation (BMT). Methods: Ninety-four matched CXR and CT examinations were performed for clinical suspicion of infectious lung disease. The time gap between CXR and CT was 48 h at maximum. The image pairs were correlated with the patients' clinical course and with the results of diagnostic bronchoalveolar lavage (BAL). An unremarkable clinical course over the subsequent seven days after imaging and/or negative microbiological culture served as the basis for excluding infectious lung disease. Positive microbiological culture and/or improvement of symptoms after antibiotic therapy were considered as evidence of infectious disease. Results: The correlation with the clinical course and/or BAL revealed a significantly higher sensitivity, negative predictive value, and accuracy for CT than for CXR (89% versus 58%, P < 0.0001; 78% versus 47%, P < 0.0001; 90% versus 68%, P < 0.0001, respectively). CT was significantly more diagnostic in BAL verified fungal and bacterial infections (P < 0.05). Conclusion: CT is significantly superior to CXR in the evaluation of infectious pulmonary disease in the late phase after BMT. Therefore, an unremarkable CXR should be followed by a CT scan to reliably detect or to accurately exclude early pulmonary infection in these patients

  19. Practical evaluation of clinical image quality (4). Determination of image quality in digital radiography system

    International Nuclear Information System (INIS)

    Katayama, Reiji

    2016-01-01

    Recently, for medical imaging, digital radiography systems are widely used in clinical practices. However, a study in the past reported that a patient radiation exposure level by digital radiography is in fact not lower than that by analog radiography system. High level of attention needs to be paid for over-exposure when using the conventional analog radiography with a screen and a film, as it results in high density of the film. However, for digital radiography systems, since the automatic adjusting function of image density is equipped with them, no attention for radiation dose need to be paid. Thus technologists tend to be careless and results in higher chance for over-exposure. Current digital radiography systems are high-performance in the image properties and capable of patient dose reduction. Especially, the image quality of the flat panel detector system is recognized, higher than that of the computed radiography system by imaging plates, in both objective and subjective evaluations. Therefore, we technologists are responsible for optimizing the balance between the image quality of the digital radiogram and the radiation dose required for each case. Moreover, it is also required for us as medical technologists to make effective use of such evaluation result of medical images for patients. (author)

  20. The relationship between aortic calcification on chest radiography and ionizing radiation in RERF's Adult Health Study

    International Nuclear Information System (INIS)

    Yamada, M.; Suzuki, G.; Masunari, N.; Kasagi, F.

    2003-01-01

    Aortic calcification has been reported to be an indicator of atherosclerosis and a predictor of coronary heart disease. However, the relationship between aortic calcification and conventional coronary risk factors or recently reported coronary risk factors including ionizing radiation, which is one kind of oxidative stress, has not been established. Objective: To investigate the relationship between aortic calcification and ionizing radiation in a longitudinal study design. The study cohort comprises the Radiation Effects Research Foundation's Adult Health Study participants which include atomic-bomb survivors and sex- and age-matched controls. A total of 522 men and 938 women identified as not having aortic calcification based on plain chest X-ray examinations at baseline examination between 1991 and 1993 were assessed regarding the presence of aortic calcification (mild/ severe calcification) about 10 years later. The relationship between cumulative incidence of aortic calcification and atomic-bomb radiation was analyzed using logistic regression analysis after adjusting for sex, age, and other coronary risk factors such as blood pressure, total cholesterol, and inflammation markers. Age-adjusted cumulative incidence of aortic calcification showed a possible increase with atomic-bomb radiation dose for both total aortic calcification and severe aortic calcification. But after adjusting for other coronary risk factors such as smoking, SBP, total cholesterol, HDL-cholesterol, hemoglobin A1c, and leukocyte neutropils, radiation dose was not a significant predictor of cumulative incidence of severe aortic calcification. Age-adjusted increase of cumulative incidence of aortic calcification with atomic-bomb radiation dose suggests ionizing radiation is one predictor of atheroscelerosis. Nevertheless, its predictive impact may not be as significant as conventional coronary risk factors

  1. Evaluation of Image According to Exposure Conditions using Contrast-Detail Phantom for Chest Digital Radiography

    International Nuclear Information System (INIS)

    Lee, In Ja; Kim, You Hyun; Kim, Chang Nam; Kim, Chang Nam; Lee, Chang Yeob; Park, Kye Yeon

    2009-01-01

    To find out proper photographing conditions in the chest DR imaging, the evaluation of images using the C-D phantom was carried out on relationship of identification capability, graininess, and exposure ratio. The conclusions were obtained as follows. 1. The patient's entrance skin Exposure (ESE) was decreased as tube voltage was increased. 2. According to the tube voltage change, the C-D phantom's identification capability of the exposure conditions was most visible at 110 kVp. 3. The identification capability according to the exposure ratio (mAs) change was most visible at 90 kVp for 0.5 times of low exposure ratio and at 110 kVp for 1.5 times. Therefore, it is known that the images were able to be better identified at a high exposure than a low exposure. 4. The graininess according to the exposure ratio at tube voltage of 110 kVp resulted in the best thing at 1.5 times of ratio when the exposure ratio was 1.5 times increased and the tube voltage was changed, the graininess showed the best result at 110 kVp. Therefore, the patient's exposure dose was low when kVp was increased and the adequate kVp was found to be 110. The image was better identified when exposure ratio was 1.5 times compared to 1.0 times. The graininess was also good when the exposure ratio became 1.5 times. The tube voltage was good at 110 kVp. However, once the exposure ratio is increased, the amount of radiation dose that the patients received get increased, so that the exposure condition has to be thoroughly considered.

  2. Sex determination based on a thoracic vertebra and ribs evaluation using clinical chest radiography.

    Science.gov (United States)

    Tsubaki, Shun; Morishita, Junji; Usumoto, Yosuke; Sakaguchi, Kyoko; Matsunobu, Yusuke; Kawazoe, Yusuke; Okumura, Miki; Ikeda, Noriaki

    2017-07-01

    Our aim was to investigate whether sex can be determined from a combination of geometric features obtained from the 10th thoracic vertebra, 6th rib, and 7th rib. Six hundred chest radiographs (300 males and 300 females) were randomly selected to include patients of six age groups (20s, 30s, 40s, 50s, 60s, and 70s). Each group included 100 images (50 males and 50 females). A total of 14 features, including 7 lengths, 5 indices for the vertebra, and 2 types of widths for ribs, were utilized and analyzed for sex determination. Dominant features contributing to sex determination were selected by stepwise discriminant analysis after checking the variance inflation factors for multicollinearity. The accuracy of sex determination using a combination of the vertebra and ribs was evaluated from the selected features by the stepwise discriminant analysis. The accuracies in each age group were also evaluated in this study. The accuracy of sex determination based on a combination of features of the vertebra and ribs was 88.8% (533/600). This performance was superior to that of the vertebra or ribs only. Moreover, sex determination of subjects in their 20s demonstrated the highest accuracy (96.0%, 96/100). The features selected in the stepwise discriminant analysis included some features in both the vertebra and ribs. These results indicate the usefulness of combined information obtained from the vertebra and ribs for sex determination. We conclude that a combination of geometric characteristics obtained from the vertebra and ribs could be useful for determining sex. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Evaluation of Image According to Exposure Conditions using Contrast-Detail Phantom for Chest Digital Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Ja [Dept. of Radiologic Tecnology, Dongnam Health College, Suwon (Korea, Republic of); Kim, You Hyun; Kim, Chang Nam [Dept. of Radiological Science, College of Health Science, Korea University, Seoul (Korea, Republic of); Kim, Chang Nam; Lee, Chang Yeob; Park, Kye Yeon [Dept. of Diagnostic Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of)

    2009-03-15

    To find out proper photographing conditions in the chest DR imaging, the evaluation of images using the C-D phantom was carried out on relationship of identification capability, graininess, and exposure ratio. The conclusions were obtained as follows. 1. The patient's entrance skin Exposure (ESE) was decreased as tube voltage was increased. 2. According to the tube voltage change, the C-D phantom's identification capability of the exposure conditions was most visible at 110 kVp. 3. The identification capability according to the exposure ratio (mAs) change was most visible at 90 kVp for 0.5 times of low exposure ratio and at 110 kVp for 1.5 times. Therefore, it is known that the images were able to be better identified at a high exposure than a low exposure. 4. The graininess according to the exposure ratio at tube voltage of 110 kVp resulted in the best thing at 1.5 times of ratio when the exposure ratio was 1.5 times increased and the tube voltage was changed, the graininess showed the best result at 110 kVp. Therefore, the patient's exposure dose was low when kVp was increased and the adequate kVp was found to be 110. The image was better identified when exposure ratio was 1.5 times compared to 1.0 times. The graininess was also good when the exposure ratio became 1.5 times. The tube voltage was good at 110 kVp. However, once the exposure ratio is increased, the amount of radiation dose that the patients received get increased, so that the exposure condition has to be thoroughly considered.

  4. Observer variation in chest radiography of acute lower respiratory infections in children: a systematic review

    International Nuclear Information System (INIS)

    Swingler, George H

    2001-01-01

    Knowledge of the accuracy of chest radiograph findings in acute lower respiratory infection in children is important when making clinical decisions. I conducted a systematic review of agreement between and within observers in the detection of radiographic features of acute lower respiratory infections in children, and described the quality of the design and reporting of studies, whether included or excluded from the review. Included studies were those of observer variation in the interpretation of radiographic features of lower respiratory infection in children (neonatal nurseries excluded) in which radiographs were read independently and a clinical population was studied. I searched MEDLINE, HealthSTAR and HSRPROJ databases (1966 to 1999), handsearched the reference lists of identified papers and contacted authors of identified studies. I performed the data extraction alone. Ten studies of observer interpretation of radiographic features of lower respiratory infection in children were identified. Seven of the studies satisfied four or more of the seven design and reporting criteria. Six studies met the inclusion criteria for the review. Inter-observer agreement varied with the radiographic feature examined. Kappa statistics ranged from around 0.80 for individual radiographic features to 0.27–0.38 for bacterial vs viral etiology. Little information was identified on observer agreement on radiographic features of lower respiratory tract infections in children. Agreement varied with the features assessed from 'fair' to 'very good'. Aspects of the quality of the methods and reporting need attention in future studies, particularly the description of criteria for radiographic features

  5. Feasibility study of flexible flat-panel X-ray detectors for digital radiography

    International Nuclear Information System (INIS)

    Joe, Ok La; Yun, Seung Man; Kim, Ho Kyung

    2010-01-01

    Flexible flat-panel detectors (FPDs), which utilize both organic photodiode (OPD) and organic thin-film transistor (OTFT) technologies, are recently concerned in digital radiography. The flexible FPD has several potential advantages, such as high accessibility to patient, avoidance of geometrical burr due to the oblique angle incidence of X-ray, great reduction in manufacturing cost due to jet-printing. At once, The OPD/OTFT arrays were fabricated by jet-printing techniques, mechanical robustness due to plastic substrates, and so on. In this study, we have investigated the feasibility of flexible FPD by comparing theoretical detective quantum efficiency (DQE) with that of the conventional amorphous silicon-based FPD. We chose copper phthalocyanine-fullerene (CuPc-C60) organic materials for the construction of the flexible FPD. DQE was calculated by the linear-systems transfer theory

  6. Quantitative assessment of the influence of anatomic noise on the detection of subtle lung nodule in digital chest radiography using fractal-feature distance

    International Nuclear Information System (INIS)

    Imai, Kuniharu; Ikeda, Mitsuru; Enchi, Yukihiro; Niimi, Takanaga

    2008-01-01

    Purpose: To confirm whether or not the influence of anatomic noise on the detection of nodules in digital chest radiography can be evaluated by the fractal-feature distance. Materials and methods: We used the square images with and without a simulated nodule which were generated in our previous observer performance study; the simulated nodule was located on the upper margin of a rib, the inside of a rib, the lower margin of a rib, or the central region between two adjoining ribs. For the square chest images, fractal analysis was conducted using the virtual volume method. The fractal-feature distances between the considered and the reference images were calculated using the pseudo-fractal dimension and complexity, and the square images without the simulated nodule were employed as the reference images. We compared the fractal-feature distances with the observer's confidence level regarding the presence of a nodule in plain chest radiograph. Results: For all square chest images, the relationships between the length of the square boxes and the mean of the virtual volumes were linear on a log-log scale. For all types of the simulated nodules, the fractal-feature distance was the highest for the simulated nodules located on the central region between two adjoining ribs and was the lowest for those located in the inside of a rib. The fractal-feature distance showed a linear relation to an observer's confidence level. Conclusion: The fractal-feature distance would be useful for evaluating the influence of anatomic noise on the detection of nodules in digital chest radiography

  7. In diagnosis of pleural effusion and pneumothorax in the intensive care unit patients: Can chest us replace bedside plain radiography?

    Directory of Open Access Journals (Sweden)

    ElShaimaa Mohamed Mohamed

    2018-06-01

    Conclusions: In evaluation of ICU patients with pleural effusion and pneumothorax, chest US is the first bedside tool with high diagnostic performance. These chest conditions are urgent especially in seriously ill patients, as both need US guided drainage. Chest US has many advantages, including non invasive examination in multiple planes, free of radiation hazard, less expensive, real-time, high sensitivity and diagnostic accuracy in chest lesions detection. Lung ultrasound is being exclusive than bedside chest X-ray and equal to chest CT in diagnosing pleural effusion and pneumothorax.

  8. TU-FG-209-11: Validation of a Channelized Hotelling Observer to Optimize Chest Radiography Image Processing for Nodule Detection: A Human Observer Study

    International Nuclear Information System (INIS)

    Sanchez, A; Little, K; Chung, J; Lu, ZF; MacMahon, H; Reiser, I

    2016-01-01

    Purpose: To validate the use of a Channelized Hotelling Observer (CHO) model for guiding image processing parameter selection and enable improved nodule detection in digital chest radiography. Methods: In a previous study, an anthropomorphic chest phantom was imaged with and without PMMA simulated nodules using a GE Discovery XR656 digital radiography system. The impact of image processing parameters was then explored using a CHO with 10 Laguerre-Gauss channels. In this work, we validate the CHO’s trend in nodule detectability as a function of two processing parameters by conducting a signal-known-exactly, multi-reader-multi-case (MRMC) ROC observer study. Five naive readers scored confidence of nodule visualization in 384 images with 50% nodule prevalence. The image backgrounds were regions-of-interest extracted from 6 normal patient scans, and the digitally inserted simulated nodules were obtained from phantom data in previous work. Each patient image was processed with both a near-optimal and a worst-case parameter combination, as determined by the CHO for nodule detection. The same 192 ROIs were used for each image processing method, with 32 randomly selected lung ROIs per patient image. Finally, the MRMC data was analyzed using the freely available iMRMC software of Gallas et al. Results: The image processing parameters which were optimized for the CHO led to a statistically significant improvement (p=0.049) in human observer AUC from 0.78 to 0.86, relative to the image processing implementation which produced the lowest CHO performance. Conclusion: Differences in user-selectable image processing methods on a commercially available digital radiography system were shown to have a marked impact on performance of human observers in the task of lung nodule detection. Further, the effect of processing on humans was similar to the effect on CHO performance. Future work will expand this study to include a wider range of detection/classification tasks and more

  9. Noninvasive diagnostic methods in primary lung cancer Part one: sputum cytology and chest radiography; Metodos diagnosticos no invasivos en cancer pulmonar primario

    Energy Technology Data Exchange (ETDEWEB)

    Bastidas, Alirio; Garcia Herreros, Plutarco; Saavedra, Alfredo; Sanchez, Edgar

    2008-07-01

    Primary lung cancer is a world wide public health problem which generates immense costs to the health system and where its cure is only achieve by an early diagnosis associated to an opportune surgical treatment. For this purpose several non invasive diagnostic methods are currently available, among them the sputum cytology, chest radiography, computed tomography scanner and the positron emission tomography. In the present article, constituted by two parts, the usefulness of these diagnostic methods as screening, diagnosis, staging and follow up tools will be discuss on the basis of the current available literature for this type of neoplasm.

  10. Use and imaging performance of CMOS flat panel imager with LiF/ZnS(Ag) and Gadox scintillation screens for neutron radiography

    Science.gov (United States)

    Cha, B. K.; kim, J. Y.; Kim, T. J.; Sim, C.; Cho, G.; Lee, D. H.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2011-01-01

    In digital neutron radiography system, a thermal neutron imaging detector based on neutron-sensitive scintillating screens with CMOS(complementary metal oxide semiconductor) flat panel imager is introduced for non-destructive testing (NDT) application. Recently, large area CMOS APS (active-pixel sensor) in conjunction with scintillation films has been widely used in many digital X-ray imaging applications. Instead of typical imaging detectors such as image plates, cooled-CCD cameras and amorphous silicon flat panel detectors in combination with scintillation screens, we tried to apply a scintillator-based CMOS APS to neutron imaging detection systems for high resolution neutron radiography. In this work, two major Gd2O2S:Tb and 6LiF/ZnS:Ag scintillation screens with various thickness were fabricated by a screen printing method. These neutron converter screens consist of a dispersion of Gd2O2S:Tb and 6LiF/ZnS:Ag scintillating particles in acrylic binder. These scintillating screens coupled-CMOS flat panel imager with 25x50mm2 active area and 48μm pixel pitch was used for neutron radiography. Thermal neutron flux with 6x106n/cm2/s was utilized at the NRF facility of HANARO in KAERI. The neutron imaging characterization of the used detector was investigated in terms of relative light output, linearity and spatial resolution in detail. The experimental results of scintillating screen-based CMOS flat panel detectors demonstrate possibility of high sensitive and high spatial resolution imaging in neutron radiography system.

  11. Chest X-Ray

    Medline Plus

    Full Text Available ... I’d like to talk with you about chest radiography also known as chest x-rays. Chest x-rays are the most ... far outweighs any risk. For more information about chest x-rays, visit Radiology Info dot org. Thank you for your time! ...

  12. Chest X-Ray

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... d like to talk with you about chest radiography also known as chest x-rays. Chest x- ...

  13. Chest X-Ray

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Chest X-ray Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  14. Comparative evaluation of chest radiography, low-field MRI, the Shwachman-Kulczycki score and pulmonary function tests in patients with cystic fibrosis

    International Nuclear Information System (INIS)

    Anjorin, Angela; Vogl, Thomas J.; Schmidt, Helga; Posselt, Hans-Georg; Smaczny, Christina; Ackermann, Hanns; Deimling, Michael; Abolmaali, Nasreddin

    2008-01-01

    The aim of this study was to investigate whether the parenchymal lung damage in patients suffering from cystic fibrosis (CF) can be equivalently quantified by the Chrispin-Norman (CN) scores determined with low-field magnetic resonance imaging (MRI) and conventional chest radiography (CXR). Both scores were correlated with pulmonary function tests (PFT) and the Shwachman-Kulczycki method (SKM). To evaluate the comparability of MRI and CXR for different states of the disease, all scores were applied to patients divided into three age groups. Seventy-three CF patients (mean SKM score: 62 ± 8) with a median age (range) of 14 years (7-32) were included. The mean CN scores determined with both imaging methods were comparable (CXR: 12.1 ± 4.7; MRI: 12.0 ± 4.5) and showed high correlation (P < 0.05, R = 0.97). Only weak correlations were found between imaging, PFT, and SKM. Both imaging modalities revealed significantly more severe disease expression with age, while PFT and SKM failed to detect early signs of disease. We conclude that imaging of the lung in CF patients is capable of detecting subtle and early parenchymal destruction before lung function or clinical scoring is affected. Furthermore, low-field MRI revealed high consistency with chest radiography and may be used for a thorough follow-up while avoiding radiation exposure. (orig.)

  15. Development of Portable Digital Radiography System with a Device for Monitoring X-ray Source-Detector Angle and Its Application in Chest Imaging

    Directory of Open Access Journals (Sweden)

    Tae-Hoon Kim

    2017-03-01

    Full Text Available This study developed a device measuring the X-ray source-detector angle (SDA and evaluated the imaging performance for diagnosing chest images. The SDA device consisted of Arduino, an accelerometer and gyro sensor, and a Bluetooth module. The SDA values were compared with the values of a digital angle meter. The performance of the portable digital radiography (PDR was evaluated using the signal-to-noise (SNR, contrast-to-noise ratio (CNR, spatial resolution, distortion and entrance surface dose (ESD. According to different angle degrees, five anatomical landmarks were assessed using a five-point scale. The mean SNR and CNR were 182.47 and 141.43. The spatial resolution and ESD were 3.17 lp/mm (157 μm and 0.266 mGy. The angle values of the SDA device were not significantly difference as compared to those of the digital angle meter. In chest imaging, the SNR and CNR values were not significantly different according to the different angle degrees. The visibility scores of the border of the heart, the fifth rib and the scapula showed significant differences according to different angles (p < 0.05, whereas the scores of the clavicle and first rib were not significant. It is noticeable that the increase in the SDA degree was consistent with the increases of the distortion and visibility score. The proposed PDR with a SDA device would be useful for application in the clinical radiography setting according to the standard radiography guidelines.

  16. Diagnostic imaging costs before and after digital tomosynthesis implementation in patient management after detection of suspected thoracic lesions on chest radiography.

    Science.gov (United States)

    Quaia, Emilio; Grisi, Guido; Baratella, Elisa; Cuttin, Roberto; Poillucci, Gabriele; Kus, Sara; Cova, Maria Assunta

    2014-02-01

    To evaluate diagnostic imaging costs before and after DTS implementation in patients with suspected thoracic lesions on CXR. Four hundred sixty-five patients (263 male, 202 female; age, 72.47 ± 11.33 years) with suspected thoracic lesion(s) after CXR underwent DTS. Each patient underwent CT when a pulmonary non-calcified lesion was identified by DTS while CT was not performed when a benign pulmonary or extrapulmonary lesion or pseudolesion was identified. The average per-patient imaging cost was calculated by normalising the costs before and after DTS implementation. In 229/465 patients who underwent DTS after suspicious CXR, DTS showed 193 pulmonary lesions and 36 pleural lesions, while in the remaining 236/465 patients, lesions were ruled out as pseudolesions of CXR. Chest CT examination was performed in 127/465 (27 %) patients while in the remaining 338/465 patients (73 %) CXR doubtful findings were resolved by DTS. The average per-patient costs of CXR, DTS and CT were 15.15, 41.55 and 113.66. DTS allowed an annual cost saving of 8,090.2 considering unenhanced CT and 19,298.12 considering contrast-enhanced CT. Considering a DTS reimbursement rate of 62.7 the break even point corresponds to 479 DTS examinations. Per-patient diagnostic imaging costs decreased after DTS implementation in patients with suspected thoracic lesions. • Digital tomosynthesis improves the diagnostic accuracy and confidence in chest radiography • Digital tomosynthesis reduces the need for CT for a suspected pulmonary lesion • Digital tomosynthesis requires a dose level equivalent to that of around two chest radiographies • Digital tomosynthesis produces a significant per-patient saving in diagnostic imaging costs.

  17. Correlation between the signal-to-noise ratio improvement factor (KSNR) and clinical image quality for chest imaging with a computed radiography system

    International Nuclear Information System (INIS)

    Moore, C S; Wood, T J; Saunderson, J R; Beavis, A W

    2015-01-01

    This work assessed the appropriateness of the signal-to-noise ratio improvement factor (K SNR ) as a metric for the optimisation of computed radiography (CR) of the chest. The results of a previous study in which four experienced image evaluators graded computer simulated chest images using a visual grading analysis scoring (VGAS) scheme to quantify the benefit of using an anti-scatter grid were used for the clinical image quality measurement (number of simulated patients  =  80). The K SNR was used to calculate the improvement in physical image quality measured in a physical chest phantom. K SNR correlation with VGAS was assessed as a function of chest region (lung, spine and diaphragm/retrodiaphragm), and as a function of x-ray tube voltage in a given chest region. The correlation of the latter was determined by the Pearson correlation coefficient. VGAS and K SNR image quality metrics demonstrated no correlation in the lung region but did show correlation in the spine and diaphragm/retrodiaphragmatic regions. However, there was no correlation as a function of tube voltage in any region; a Pearson correlation coefficient (R) of  −0.93 (p  =  0.015) was found for lung, a coefficient (R) of  −0.95 (p  =  0.46) was found for spine, and a coefficient (R) of  −0.85 (p  =  0.015) was found for diaphragm. All demonstrate strong negative correlations indicating conflicting results, i.e. K SNR increases with tube voltage but VGAS decreases. Medical physicists should use the K SNR metric with caution when assessing any potential improvement in clinical chest image quality when introducing an anti-scatter grid for CR imaging, especially in the lung region. This metric may also be a limited descriptor of clinical chest image quality as a function of tube voltage when a grid is used routinely. (paper)

  18. Detection of simulated pulmonary nodules by single-exposure dual-energy computed radiography of the chest: effect of a computer-aided diagnosis system (Part 2)

    International Nuclear Information System (INIS)

    Kido, Shoji; Kuriyama, Keiko; Kuroda, Chikazumi; Nakamura, Hironobu; Ito, Wataru; Shimura, Kazuo; Kato, Hisatoyo

    2002-01-01

    Objective: To evaluate the performance of the computer-aided diagnosis (CAD) scheme on the detection of pulmonary nodules (PNs) in single-exposure dual-energy subtraction computed radiography (CR) images of the chest, and to evaluate the effect of this CAD scheme on radiologists' detectabilities. Methods and material: We compared the detectability by the CAD scheme with the detectability by 12 observers by using conventional CR (C-CR) and bone-subtracted CR (BS-CR) images of 25 chest phantoms with a low-contrast nylon nodule. Results: Both in the CAD scheme and for the observers, the detectability of BS-CR images was superior to that of C-CR images (P<0.005). The detection performance of the CAD scheme was equal to that of the observers. The nodules detected by the CAD did not necessarily coincide with those by the observers. Thus, if observers can use the results of the CAD system as a 'second opinion', their detectabilities increase. Conclusion: The CAD system for detection of PNs in the single-exposure dual-energy subtraction method is promising for improving radiologists' detectabilities of PNs

  19. Accuracy of Lung Ultrasonography versus Chest Radiography for the Diagnosis of Adult Community-Acquired Pneumonia: Review of the Literature and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Xiong Ye

    Full Text Available Lung ultrasonography (LUS is being increasingly utilized in emergency and critical settings. We performed a systematic review of the current literature to compare the accuracy of LUS and chest radiography (CR for the diagnosis of adult community-acquired pneumonia (CAP. We searched in Pub Med, EMBASE dealing with both LUS and CR for diagnosis of adult CAP, and conducted a meta-analysis to evaluate the diagnostic accuracy of LUS in comparison with CR. The diagnostic standard that the index test compared was the hospital discharge diagnosis or the result of chest computed tomography scan as a "gold standard". We calculated pooled sensitivity and specificity using the Mantel-Haenszel method and pooled diagnostic odds ratio using the DerSimonian-Laird method. Five articles met our inclusion criteria and were included in the final analysis. Using hospital discharge diagnosis as reference, LUS had a pooled sensitivity of 0.95 (0.93-0.97 and a specificity of 0.90 (0.86 to 0.94, CR had a pooled sensitivity of 0.77 (0.73 to 0.80 and a specificity of 0.91 (0.87 to 0.94. LUS and CR compared with computed tomography scan in 138 patients in total, the Z statistic of the two summary receiver operating characteristic was 3.093 (P = 0.002, the areas under the curve for LUS and CR were 0.901 and 0.590, respectively. Our study indicates that LUS can help to diagnosis adult CAP by clinicians and the accuracy was better compared with CR using chest computed tomography scan as the gold standard.

  20. The value of digital tomosynthesis of the chest as a problem-solving tool for suspected pulmonary nodules and hilar lesions detected on chest radiography.

    Science.gov (United States)

    Galea, Angela; Dubbins, Paul; Riordan, Richard; Adlan, Tarig; Roobottom, Carl; Gay, David

    2015-05-01

    To assess the capability of digital tomosynthesis (DTS) of the chest compared to a postero-anterior (PA) and lateral chest radiograph (CXR) in the diagnosis of suspected but unconfirmed pulmonary nodules and hilar lesions detected on a CXR. Computed tomography (CT) was used as the reference standard. 78 patients with suspected non-calcified pulmonary nodules or hilar lesions on their CXR were included in the study. Two radiologists, blinded to the history and CT, prospectively analysed the CXR (PA and lateral) and the DTS images using a picture archiving and communication workstation and were asked to designate one of two outcomes: true intrapulmonary lesion or false intrapulmonary lesion. A CT of the chest performed within 4 weeks of the CXR was used as the reference standard. Inter-observer agreement and time to report the modalities were calculated for CXR and DTS. There were 34 true lesions confirmed on CT, 12 were hilar lesions and 22 were peripheral nodules. Of the 44 false lesions, 37 lesions were artefactual or due to composite shadow and 7 lesions were real but extrapulmonary simulating non-calcified intrapulmonary lesions. The PA and lateral CXR correctly classified 39/78 (50%) of the lesions, this improved to 75/78 (96%) with DTS. The sensitivity and specificity was 0.65 and 0.39 for CXR and 0.91 and 1 for DTS. Based on the DTS images, readers correctly classified all the false lesions but missed 3/34 true lesions. Two of the missed lesions were hilar in location and one was a peripheral nodule. All three missed lesions were incorrectly classified on DTS as composite shadow. DTS improves diagnostic confidence when compared to a repeat PA and lateral CXR in the diagnosis of both suspected hilar lesions and pulmonary nodules detected on CXR. DTS is able to exclude most peripheral pulmonary nodules but caution and further studies are needed to assess its ability to exclude hilar lesions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Reducing the absorbed dose in analogue radiography of infant chest images by improving the image quality, using image processing techniques

    International Nuclear Information System (INIS)

    Karimian, A.; Yazdani, S.; Askari, M. A.

    2011-01-01

    Radiographic inspection is one of the most widely employed techniques for medical testing methods. Because of poor contrast and high un-sharpness of radiographic image quality in films, converting radiographs to a digital format and using further digital image processing is the best method of enhancing the image quality and assisting the interpreter in their evaluation. In this research work, radiographic films of 70 infant chest images with different sizes of defects were selected. To digitise the chest images and employ image processing the two algorithms (i) spatial domain and (ii) frequency domain techniques were used. The MATLAB environment was selected for processing in the digital format. Our results showed that by using these two techniques, the defects with small dimensions are detectable. Therefore, these suggested techniques may help medical specialists to diagnose the defects in the primary stages and help to prevent more repeat X-ray examination of paediatric patients. (authors)

  2. Improvement in visibility of simulated lung nodules on computed radiography (CR) chest images by use of temporal subtraction technique

    International Nuclear Information System (INIS)

    Oda, Nobuhiro; Fujimoto, Keiji; Murakami, Seiichi; Katsuragawa, Shigehiko; Doi, Kunio; Nakata, Hajime

    1999-01-01

    A temporal subtraction image obtained by subtraction of a previous image from a current one can enhance interval change on chest images. In this study, we compared the visibility of simulated lung nodules on CR images with and without temporal subtraction. Chest phantom images without and with simulated nodules were obtained as previous and current images, respectively, by a CR system. Then, subtraction images were produced with an iterative image warping technique. Twelve simulated nodules were attached on various locations of the chest phantom. The diameter of nodules having a CT number of 47 ranged from 3 mm to 10 mm. Seven radiologists subjectively evaluated the visibility of simulated nodules on CR images with and without temporal subtraction using a three-point rating scale (0: invisible, +1: questionable, +2:visible). The minimum diameter of simulated nodules visible at a frequency greater than 50% was 4 mm on the CR images with temporal subtraction and 6 mm on those without. Our results indicated that the subtraction images clearly improved the visibility of simulated nodules. (author)

  3. Chest tube placement in thorax trauma - comparison chest X-ray and computed tomography (CT)

    International Nuclear Information System (INIS)

    Heim, P.; Maas, R.; Buecheler, E.; Tesch, C.

    1998-01-01

    Estimation of chest tube placement in patients with thoracic trauma with regard to chest tube malposition in chest radiography in the supine position compared to additional computed tomography of the thorax. Material and methods: Apart from compulsory chest radiography after one or multiple chest tube insertions, 31 severely injured patients with thoracic trauma underwent a CT scan of the thorax. These 31 patients with 40 chest tubes constituted the basis for the present analysis. Results: In chest radiography in the supine position there were no chest tube malpositions (n=40); In the CT scans 25 correct positions, 7 pseudo-malpositions, 6 intrafissural and 2 intrapulmonary malpositions were identified. Moreover 16 sufficient, 18 insufficient and 6 indifferent functions of the chest tubes were seen. Conclusion: In case of lasting clinical problems and questionable function of the chest tube, chest radiography should be supplemented by a CT scan of the thorax in order to estimate the position of the chest tube. (orig.) [de

  4. The Potential Role of Grid-Like Software in Bedside Chest Radiography in Improving Image Quality and Dose Reduction: An Observer Preference Study.

    Science.gov (United States)

    Ahn, Su Yeon; Chae, Kum Ju; Goo, Jin Mo

    2018-01-01

    To compare the observer preference of image quality and radiation dose between non-grid, grid-like, and grid images. Each of the 38 patients underwent bedside chest radiography with and without a grid. A grid-like image was generated from a non-grid image using SimGrid software (Samsung Electronics Co. Ltd.) employing deep-learning-based scatter correction technology. Two readers recorded the preference for 10 anatomic landmarks and the overall appearance on a five-point scale for a pair of non-grid and grid-like images, and a pair of grid-like and grid images, respectively, which were randomly presented. The dose area product (DAP) was also recorded. Wilcoxon's rank sum test was used to assess the significance of preference. Both readers preferred grid-like images to non-grid images significantly ( p software significantly improved the image quality of non-grid images to a level comparable to that of grid images with a relatively lower level of radiation exposure.

  5. Development of an imaging-planning program for screen/film and computed radiography mammography for breasts with short chest wall to nipple distance.

    Science.gov (United States)

    Dong, S L; Su, J L; Yeh, Y H; Chu, T C; Lin, Y C; Chuang, K S

    2011-04-01

    Imaging breasts with a short chest wall to nipple distance (CWND) using a traditional mammographic X-ray unit is a technical challenge for mammographers. The purpose of this study is the development of an imaging-planning program to assist in determination of imaging parameters of screen/film (SF) and computed radiography (CR) mammography for short CWND breasts. A traditional mammographic X-ray unit (Mammomat 3000, Siemens, Munich, Germany) was employed. The imaging-planning program was developed by combining the compressed breast thickness correction, the equivalent polymethylmethacrylate thickness assessment for breasts and the tube loading (mAs) measurement. Both phantom exposures and a total of 597 exposures were used for examining the imaging-planning program. Results of the phantom study show that the tube loading rapidly decreased with the CWND when the automatic exposure control (AEC) detector was not fully covered by the phantom. For patient exposures with the AEC fully covered by breast tissue, the average fractional tube loadings, defined as the ratio of the predicted mAs using the imaging-planning program and mAs of the mammogram, were 1.10 and 1.07 for SF and CR mammograms, respectively. The predicted mAs values were comparable to the mAs values, as determined by the AEC. By applying the imaging-planning program in clinical practice, the experiential dependence of the mammographer for determination of the imaging parameters for short CWND breasts is minimised.

  6. Compton radiography, 2

    International Nuclear Information System (INIS)

    Okuyama, Shinichi; Sera, Koichiro; Fukuda, Hiroshi; Shishido, Fumio; Mishina, Hitoshi.

    1977-01-01

    Compton radiography, a tomographic technic with Compton-scattered rays of a monochromatic gamma ray beam, was feasible of tomographing a chest phantom. The result suggested that the technic could be extended to imaging of the lung and the surrounding structures of the chest wall, mediastinum and liver in Compton tomographic mode. (auth.)

  7. A preliminary design of mechanical device on industrial digital radiography equipment design

    International Nuclear Information System (INIS)

    Nur Khasan; Samuel Praptoyo

    2015-01-01

    A preliminary design of mechanical device on industrial digital radiography equipment has been done. this design is intended as a basis for the manufacture of complete facilities for the realization a prototype on industrial digital radiography equipment. the design and construction were carried out by paying attention to the general configuration of the basic design in which its mechanical design has several components with specific dimensions and heavy mass. this design consist of a main frame holder, flat panel detector support and hydraulic hand stacker for mounting the x-ray machine. this mechanical device design will then be fabricated to facilitate and assist work of digital radiographic retrieval. computer application programs sketch-up is used to draw this design and the analysis stress of autodesk inventor to analysis the strength construction design. the results of this design are the configuration drawing, sketch drawings of construction and the safety factor of construction design with a minimum value of 2.39 as well as a maximum value of 15 when to be simulated by the load 500 Kg which is 4 times of total workload. (author)

  8. Structural analysis of jewelry from the Moche tomb of the `lady of Cao' by X-ray digital radiography

    Science.gov (United States)

    Azeredo, S. R.; Cesareo, R.; Franco, R.; Fernandez, A.; Bustamante, A.; Lopes, R. T.

    2018-04-01

    Nose ornaments from the tomb of the `Lady of Cao', a mummified woman representative of the Moche culture and dated to the third-or-fourth century AD, were analyzed by X-ray digital radiography. These spectacular gold and silver jewels are some of the most sophisticated metalworking ever produced in ancient America. The Mochecivilization flourished along the north coast of present-day Peru, between the Andes and the Pacific Ocean, approximately between 100 and 600 AD. The Moche were very sophisticated artisans and metal smiths, being considered the finest producers of jewels and artifacts of the region. A portable X-ray digital radiography (XDR) system consisting of a flat panel detector with high resolution image and a mini X-ray tube was used for the structural analysis of the Moche jewels aiming at inferring different joining methods of the silver-gold sheets. The radiographic analysis showed some differences in the joint of the silver-and-gold sheets. Presence of filler material and adhesive for joining the silver-and-gold sheets was visible as well as silver-gold junctions without filler material (or with a material invisible in radiography). Furthermore, the technique demonstrated the advantage of using a portable XDR micro system when the sample cannot be brought to the laboratory.

  9. Modified Chrispin-Norman chest radiography score for cystic fibrosis: observer agreement and correlation with lung function

    International Nuclear Information System (INIS)

    Jong, P.A. de; Achterberg, J.A.; Kessels, O.A.M.; Beek, F.J.; Ginneken, B. van; Hogeweg, L.; Terheggen-Lagro, S.W.J.

    2011-01-01

    To test observer agreement and two strategies for possible improvement (consensus meeting and reference images) for the modified Chrispin-Norman score for children with cystic fibrosis (CF). Before and after a consensus meeting and after developing reference images three observers scored sets of 25 chest radiographs from children with CF. Observer agreement was tested for line, ring, mottled and large soft shadows, for overinflation and for the composite modified Chrispin-Norman score. Correlation with lung function was assessed. Before the consensus meeting agreement between observers 1 and 2 was moderate-good, but with observer 3 agreement was poor-fair. Scores correlated significantly with spirometry for observers 1 and 2 (-0.72< R<-0.42, P < 0.05), but not for observer 3. Agreement with observer 3 improved after the consensus meeting. Reference images improved agreement for overinflation and mottled and large shadows and correlation with lung function, but agreement for the modified Chrispin-Norman score did not improve further. Consensus meetings and reference images improve among-observer agreement for the modified Chrispin-Norman score, but good agreement was not achieved among all observers for the modified Chrispin-Norman score and for bronchial line and ring shadows. (orig.)

  10. Modified Chrispin-Norman chest radiography score for cystic fibrosis: observer agreement and correlation with lung function

    Energy Technology Data Exchange (ETDEWEB)

    Jong, P.A. de; Achterberg, J.A.; Kessels, O.A.M.; Beek, F.J. [Department of Radiology, University Medical Center Utrecht, Wilhelmina Children' s Hospital, Utrecht (Netherlands); Ginneken, B. van; Hogeweg, L. [Radboud University Nijmegen Medical Centre, Department of Radiology, Nijmegen (Netherlands); Image Sciences Institute, University Medical Center Utrecht, Utrecht (Netherlands); Terheggen-Lagro, S.W.J. [University Medical Center Utrecht, Wilhelmina Children' s Hospital, Department of Pediatric Pulmonology, Utrecht (Netherlands)

    2011-04-15

    To test observer agreement and two strategies for possible improvement (consensus meeting and reference images) for the modified Chrispin-Norman score for children with cystic fibrosis (CF). Before and after a consensus meeting and after developing reference images three observers scored sets of 25 chest radiographs from children with CF. Observer agreement was tested for line, ring, mottled and large soft shadows, for overinflation and for the composite modified Chrispin-Norman score. Correlation with lung function was assessed. Before the consensus meeting agreement between observers 1 and 2 was moderate-good, but with observer 3 agreement was poor-fair. Scores correlated significantly with spirometry for observers 1 and 2 (-0.72

  11. Comparison of the image quality of digital radiography system and film screen system - Radiologist' rating of the visibility of normal anatomic - Structures in chest PA, Skull radiograph and K. U. B

    International Nuclear Information System (INIS)

    Song, Kounn Sik; Kim, Young Goo; Lee, Jong Beum; Kim, Kun Sang

    1987-01-01

    Digital image acquisition and display is widely used in computed tomography, ultrasonography, digital subtraction angiography, nuclear medicine and magnetic resonance image. But most of the radiological examinations performed in radiology department are made by using conventional system. The development of the digital radiography system is essential if totally digitized radiology department is desired. The advantages of digitizing the radiographic information are usually discussed in terms of PACS (picture archiving and communication system), furthermore there are many other advantages such as contrast modification, spatial filtering subtraction and superimposition of the images through the image processing by computer. Currently several approaches are under development or in clinical use, the most promising approach is the use of imaging plate composed of photostimulate phosphors such as barium fluorohalide crystal read with a He-Ne laser to produce digital radiographic images. Another promising approach is scan projection radiography. The authors performed the clinical study of comparing the image qualities of digital radiography system using scanning laser luminescence (FCR) and conventional film-screen system in chest PA, skull radiography and K. U. B. in terms of the visibility of the normal anatomic structure rating those (qualities) on a scale of 0 to 3 and obtained the following results. Normal contrast digital images are comparable to conventional film-screen images, but the images of high frequency enhancement is far superior to conventional film-screen especially in peripherally located structures such as skin, subcutaneous fat, musculoskeletal systems, nasal bone, inner and outer table of the skull including the diploic space, paranasal sinuses, nasopharynx and larynx, trachea and main bronchi, mediastinal structures, retrocardiac and subphrenic vascular markings. Another promising aspects of digital radiography system is its wide exposure latitude and

  12. A forward bias method for lag correction of an a-Si flat panel detector

    International Nuclear Information System (INIS)

    Starman, Jared; Tognina, Carlo; Partain, Larry; Fahrig, Rebecca

    2012-01-01

    Purpose: Digital a-Si flat panel (FP) x-ray detectors can exhibit detector lag, or residual signal, of several percent that can cause ghosting in projection images or severe shading artifacts, known as the radar artifact, in cone-beam computed tomography (CBCT) reconstructions. A major contributor to detector lag is believed to be defect states, or traps, in the a-Si layer of the FP. Software methods to characterize and correct for the detector lag exist, but they may make assumptions such as system linearity and time invariance, which may not be true. The purpose of this work is to investigate a new hardware based method to reduce lag in an a-Si FP and to evaluate its effectiveness at removing shading artifacts in CBCT reconstructions. The feasibility of a novel, partially hardware based solution is also examined. Methods: The proposed hardware solution for lag reduction requires only a minor change to the FP. For pulsed irradiation, the proposed method inserts a new operation step between the readout and data collection stages. During this new stage the photodiode is operated in a forward bias mode, which fills the defect states with charge. A Varian 4030CB panel was modified to allow for operation in the forward bias mode. The contrast of residual lag ghosts was measured for lag frames 2 and 100 after irradiation ceased for standard and forward bias modes. Detector step response, lag, SNR, modulation transfer function (MTF), and detective quantum efficiency (DQE) measurements were made with standard and forward bias firmware. CBCT data of pelvic and head phantoms were also collected. Results: Overall, the 2nd and 100th detector lag frame residual signals were reduced 70%-88% using the new method. SNR, MTF, and DQE measurements show a small decrease in collected signal and a small increase in noise. The forward bias hardware successfully reduced the radar artifact in the CBCT reconstruction of the pelvic and head phantoms by 48%-81%. Conclusions: Overall, the forward bias method has been found to greatly reduce detector lag ghosts in projection data and the radar artifact in CBCT reconstructions. The method is limited to improvements of the a-Si photodiode response only. A future hybrid mode may overcome any limitations of this method.

  13. Rate of transformation and normal range about cardiac size and cardiothoracic ratio according to patient position and age at chest radiography of Korean adult man

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Young Cheol [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Lim, Cheong Hwan; Jung, Hong Ryang [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of); Kim, Yun Min [Dept. of Radiotechnology, Wonkwang Health Science University, Iksan (Korea, Republic of); Hong, Dong Hee [Dept. of Radiological Science, Far East University, Eumseong (Korea, Republic of)

    2017-06-15

    Purpose of this study is present the normal range of cardiac size and cardiothoracic ratio according to patient position(chest PA and AP) and age of Korean adult male on digital chest X - ray, And to propose a mutually compatible conversion rate. 1,024 males were eligible for this study, among 1,300 normal chest patients who underwent chest PA and low-dose CT examinations on the same day at the 'S' Hospital Health Examination Center in Seoul From January to December 2014. CS and CTR were measured by Danzer (1919). The mean difference between CS and CTR was statistically significant (p<0.01) in Chest PA (CS 135.48 mm, CTR 43.99%) and Chest AP image (CS 155.96 mm, CTR 51.75%). There was no statistically significant difference between left and right heart in chest PA and AP images(p>0.05). CS showed statistically significant difference between Chest PA (p>0. 05) and Chest AP (p<0.05). The thorax size and CTR were statistically significant (p<0.01) in both age and chest PA and AP. Result of this study, On Chest AP image CS was magnified 15%, CTR was magnified 17% compare with Chest PA image. CS and CTR were about 10% difference by changing posture at all ages.

  14. On-demand rather than daily-routine chest radiography prescription may change neither the number nor the impact of chest computed tomography and ultrasound studies in a multidisciplinary intensive care unit.

    Science.gov (United States)

    Kröner, Anke; Binnekade, Jan M; Graat, Marleen E; Vroom, Margreeth B; Stoker, Jaap; Spronk, Peter E; Schultz, Marcus J

    2008-01-01

    Elimination of daily-routine chest radiographs (CXRs) may influence chest computed tomography (CT) and ultrasound practice in critically ill patients. This was a retrospective cohort study including all patients admitted to a university-affiliated intensive care unit during two consecutive periods of 5 months, one before and one after elimination of daily-routine CXR. Chest CT and ultrasound studies were identified retrospectively by using the radiology department information system. Indications for and the diagnostic/therapeutic yield of chest CT and ultrasound studies were collected. Elimination of daily-routine CXR resulted in a decrease of CXRs per patient day from 1.1 +/- 0.3 to 0.6 +/- 0.4 (P chest CT studies nor the ratio of chest CT studies per patient day changed with the intervention: Before elimination of daily-routine CXR, 52 chest CT studies were obtained from 747 patients; after elimination, 54 CT studies were obtained from 743 patients. Similarly, chest ultrasound practice was not affected by the change of CXR strategy: Before and after elimination, 21 and 27 chest ultrasound studies were performed, respectively. Also, timing of chest CT and ultrasound studies was not different between the two study periods. During the two periods, 40 of 106 chest CT studies (38%) and 18 of 48 chest ultrasound studies (38%) resulted in a change in therapy. The combined therapeutic yield of chest CT and ultrasound studies did not change with elimination of daily-routine CXR. Elimination of daily-routine CXRs may not affect chest CT and ultrasound practice in a multidisciplinary intensive care unit.

  15. Evaluation of digital detector arrays systems for industrial radiography

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aline S.S.; Oliveira, Davi F.; Gomes, Célio S.; Azeredo, Soraia R.; Lopes, Ricardo T., E-mail: aline@lin.ufrj.br, E-mail: davi@lin.ufrj.br.br, E-mail: celio@lin.ufrj.br, E-mail: soraia@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br, E-mail: davi.oliveira@uerj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear

    2017-07-01

    Digital Detector Arrays (DDA) or Flat Panel Detector (FPD) is a highly efficient technique that is used in nondestructive testing of internal features of an object. The evaluation of DDA systems for industrial radiography is important to ensure the image quality and to enables long-term stability of this system. This evaluation is specified by ASTM E2737 - 10, which describes the fundamental parameters of DDA systems to be measured. The tests require the usage of either the five-groove wedge or the duplex plate phantom with separate Image Quality Indicators (IQIs). The purpose of this work was evaluate the radiographic performance achieved using both techniques in two DDA systems manufactured by GEIT: DXR250P and DXR250V, which have thallium-doped cesium iodide (CsI:Tl) and terbium-doped gadolinium oxysulfide (Gd{sub 2}O{sub 2}S:Tb - GOS) scintillators, respectively. For this purpose, it was used an X-ray equipment as radiation source. The image quality parameters analyzed were Image Lag (IL), Offset Level (OL), Bad Pixel distribution, Burn In (BI), Spatial Resolution (SR), Material Thickness Range (MTR), Contrast Sensitivity (CS), Signal Level (SL) and Signal-to-Noise Ratio (SNR). As result of this study, has been observed that the use of the five-groove wedge phantom made the measurements to become easier to execute. Regarding the DDA system, the DXR250P presented more IL and BI, but produced images with better CS and SNR and needed a dose almost twice smaller than the DXR250V to achieve a similar SL. (author)

  16. Evaluation of digital detector arrays systems for industrial radiography

    International Nuclear Information System (INIS)

    Silva, Aline S.S.; Oliveira, Davi F.; Gomes, Célio S.; Azeredo, Soraia R.; Lopes, Ricardo T.

    2017-01-01

    Digital Detector Arrays (DDA) or Flat Panel Detector (FPD) is a highly efficient technique that is used in nondestructive testing of internal features of an object. The evaluation of DDA systems for industrial radiography is important to ensure the image quality and to enables long-term stability of this system. This evaluation is specified by ASTM E2737 - 10, which describes the fundamental parameters of DDA systems to be measured. The tests require the usage of either the five-groove wedge or the duplex plate phantom with separate Image Quality Indicators (IQIs). The purpose of this work was evaluate the radiographic performance achieved using both techniques in two DDA systems manufactured by GEIT: DXR250P and DXR250V, which have thallium-doped cesium iodide (CsI:Tl) and terbium-doped gadolinium oxysulfide (Gd 2 O 2 S:Tb - GOS) scintillators, respectively. For this purpose, it was used an X-ray equipment as radiation source. The image quality parameters analyzed were Image Lag (IL), Offset Level (OL), Bad Pixel distribution, Burn In (BI), Spatial Resolution (SR), Material Thickness Range (MTR), Contrast Sensitivity (CS), Signal Level (SL) and Signal-to-Noise Ratio (SNR). As result of this study, has been observed that the use of the five-groove wedge phantom made the measurements to become easier to execute. Regarding the DDA system, the DXR250P presented more IL and BI, but produced images with better CS and SNR and needed a dose almost twice smaller than the DXR250V to achieve a similar SL. (author)

  17. Dose in conventional radiography

    International Nuclear Information System (INIS)

    Acuna D, E.; Padilla R, Z. P.; Escareno J, E.; Vega C, H. R.

    2011-10-01

    It has been pointed out that medical exposures are the most significant sources of exposure to ionizing radiation for the general population. Inside the medical exposures the most important is the X-ray use for diagnosis, which is by far the largest contribution to the average dose received by the population. From all studies performed in radiology the chest radiography is the most abundant. In an X-ray machine, voltage and current are combined to obtain a good image and a reduce dose, however due to the workload in a radiology service individual dose is not monitored. In order to evaluate the dose due to chest radiography in this work a plate phantom was built according to the ISO recommendations using methylmethacrylate walls and water. The phantom was used in the Imaging department of the Zacatecas General Hospital as a radiology patient asking for a chest study; using thermoluminescent dosimeters, TLD 100 the kerma at the surface entrance was determined. (Author)

  18. The mass miniature chest radiography programme in Cape Town, South Africa, 1948-1994: The impact of active tuberculosis case finding

    NARCIS (Netherlands)

    Hermans, S. M.; Andrews, J. R.; Bekker, L.-G.; Wood, R.

    2016-01-01

    Tuberculosis (TB) control programmes rely mainly on passive detection of symptomatic individuals. The resurgence of TB has rekindled interest in active case finding. Cape Town (South Africa) had a mass miniature radiography (MMR) screening programme from 1948 to 1994. To evaluate screening coverage,

  19. Interobserver agreement in the assessment of pulmonary infiltrates on chest radiography in community-acquired pneumonia; Detektion pneumonischer Infiltrate bei ambulant erworbener Pneumonie: Uebereinstimmung in der Befundung der Roentgen-Thoraxaufnahme

    Energy Technology Data Exchange (ETDEWEB)

    Pauls, S.; Billich, C.; Boll, D.; Aschoff, A.J. [Diagnostische und Interventionelle Radiologie, Universitaetskliniken Ulm (Germany); Krueger, S. [Medizinische Klinik I, Universitaetskliniken RWTH Aachen (Germany); Richter, K.; Marre, R.; Gonschior, S. [Mikrobiologie und Hygiene, Universitaetskliniken Ulm (Germany); Muche, R. [Inst. fuer Biometrie, Univ. Ulm (Germany); Welte, T. [Abt. fuer Pneumologie, Medizinische Hochschule Hannover (Germany); Schumann, C. [Medizinische Klinik II, Universitaetskliniken Ulm (Germany); Suttorp, N. [Abt. Innere Medizin, Charite Universitaetsmedizin Berlin (Germany)

    2007-11-15

    Purpose: To assess interobserver agreement (IOA) in the diagnosis of pulmonary infiltrates on chest X-rays for patients with community-acquired pneumonia (CAP). Materials and methods: From 7/2002 to 12/2005, 806 adults with CAP were included in the multicenter study 'CAPNETZ' (7 hospitals). Inclusion criteria were clinical signs of pneumonia and pulmonary opacification on chest X-rays. Each X-ray was reevaluated by two radiologists from the university hospital in consensus reading against the interpreter at the referring hospital in regard to: presence of infiltrate (yes/no/equivocal), transparency ({<=}/> 50%), localization, and pattern of infiltrates (alveolar/interstitial). The following parameters were documented: digital or film radiography, hospitalization, fever, findings of auscultation, microbiological findings. Results: The overall IOA concerning the detection of infiltrates was 77.7% (n = 626; Cl 0.75 - 0.81), the infiltrates were not verified in 16.4% (n = 132) by the referring radiologist with equivocal findings in 5.9% (n = 48). The IOA of the different clinical centers varied between 63.2% (n = 38, Cl 0.48 - 0.78) and 92.3% (n = 65, Cl 0.86 - 0.99). The IOA for the diagnosis of infiltrates was significantly higher for inpatients with 82.6% (n = 546; Cl 0.80-0.85) than for outpatients with 55.2% (n = 80; Cl 0.47 - 0.63), p < 0.0001. The IOA of infiltrates with a transparency > 50% was 95.1% (n = 215; Cl 0.92 - 0.98) versus 80.4% (n = 403; Cl 0.77 - 0.84) for infiltrates with a transparency > 50% (p < 0.0001). In patients with positive auscultation, the IOA was higher (p = 0,034). Chest X-rays of patients with antibiotic therapy or an alveolar infiltrate showed more equivocal findings compared to patients without these features. Conclusion: There is considerable interobserver variability in the diagnosis of pulmonary infiltrates on chest radiographs. The IOA is higher in more opaque infiltrates, positive auscultation and inpatients. (orig.)

  20. Diagnosis of osteoporosis in rural Arctic Greenland: a clinical case using plain chest radiography for secondary prevention and consideration of tools for primary prevention in remote areas.

    Science.gov (United States)

    Fleischer, Inuuteq; Schæbel, Louise K; Albertsen, Nadja; Sørensen, Vibeke N; Andersen, Stig

    2017-01-01

    Osteoporosis is a frequent disease in many populations. The hallmark is fragility fractures, which are harbingers of future fractures, disability, mortality and cost on society. The occurrence increases with age, low vitamin D level and smoking. Smoking rates are high, vitamin D is low and life expectancy is rising steeply in Greenland, as is the need for focus on osteoporosis. We report a case that uses a simple and readily available tool to diagnose osteoporosis at the hospital in Sisimiut, a town of 5000 inhabitants on the west coast of Greenland. A 51-year-old Inuit woman was seen due to lower back pain. No trauma could be recalled. Laboratory results showed a low vitamin D level and normal S-calcium, S-phosphate, S-parathyroid hormone, S-thyrotropin, erythrocyte sedimentation rate, S-creatinine and hemoglobin. The lateral chest radiograph demonstrated a reduction of anterior height of the seventh and ninth thoracic vertebral bodies of 50% and 40% respectively. Chest radiographs are frequently done in the towns along the vast coastline of Greenland, the world's largest island. They are transferred to the hospital in the capital city Nuuk using existing tele-technology, and specialist evaluations are given in electronic records available at the coastal hospitals. Effective therapies for osteoporosis are available and the identification of vertebral fractures that merit treatment may prevent future fractures, morbidity and mortality. Fragility fractures are frequent in old age and the steep rise in life expectancy and in the number of old people in Greenland emphasize the need for a focus on management of osteoporosis. Geography provides a diagnostic challenge to rural and remote areas that can be overcome by the use of lateral chest radiographs as it relies on facilities readily available. Clinical risk assessment tools with high specificity may support further osteoporosis risk prediction in remote Arctic societies.

  1. Computer radiography - indirect digital radiography

    International Nuclear Information System (INIS)

    Jezierski, G.

    2008-01-01

    Implementation of the new European standards for industrial radiography with the use of storage phosphor imaging plates will result in the arousing of interest among numerous laboratories in non-destructive testing with application of the new method of testing to replace conventional radiography used so far, i.e. film radiography. Computer radiography is quite commonly used for medical radiography, where the fundamental problem consists in reduction of the radiation dose during the examination of a patient. However, it must be kept in mind that industrial applications have a little bit different requirements when compared with medical radiography. The article describes only new method for radiographic testing. (author)

  2. Trauma of the chest

    International Nuclear Information System (INIS)

    Reuter, M.

    1996-01-01

    This paper describes the typical radiologic findings in chest trauma, and the value of conventional radiography, CT, MRI, and aortography is discussed. Conventional radiography rather than cross-sectional imaging is the mainstay in diagnosing thoracic trauma. During the critical phase with often concomitant shock, pelvic and spinal injuries tailored raiographic views or even upright chest radiographs are impractical. The severely traumatized patient is usually radiographed in the supine position and suboptimal roentgenograms may have to be accepted for several reasons. It is well documented that many abnormalities detected on CT were not apparent on conventional radiographs, but CT is reserved for hemodynamical stable patients. Nevertheless certain situations like aortic rupture require further evaluation by CT and aortography. (orig./MG)

  3. Validation od computational model ALDERSON/EGSnrc for chest radiography; Validação do modelo computacional Alderson/EGSnrc para radiografias de tórax

    Energy Technology Data Exchange (ETDEWEB)

    Muniz, Bianca C. [Instituto Federal de Educação, Ciência e Tecnologia de Pernambuco - IFPE, Recife, PE (Brazil); Santos, André L. dos; Menezes, Claudio J.M., E-mail: andre.luiz_76@yahoo.com.br, E-mail: cjmm@cnen.gov.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2017-07-01

    To perform dose studies in situations of exposure to radiation, without exposing individuals, the numerical dosimetry uses Computational Exposure Models (ECM). Composed essentially by a radioactive source simulator algorithm, a voxel phantom representing the human anatomy and a Monte Carlo code, the ECMs must be validated to determine the reliability of the physical array representation. The objective of this work is to validate the ALDERSON / EGSnrc MCE by through comparisons between the experimental measurements obtained with the ionization chamber and virtual simulations using Monte Carlo Method to determine the ratio of the input and output radiation dose. Preliminary results of these comparisons showed that the ECM reproduced the results of the experimental measurements performed with the physical phantom with a relative error of less than 10%, validating the use of this model for simulations of chest radiographs and estimates of radiation doses in tissues in the irradiated structures.

  4. Comparison of chest radiography and static respiratory compliance in the assessment of the severity of pulmonary diseases in newborns with respiratory distress

    International Nuclear Information System (INIS)

    Lischka, A.; Coradello, H.; Simbruner, G.; Popow, C.

    1984-01-01

    In 55 newborn infants with respiratory distress syndrome (RDS) we compared chest radiographs and static respiratory compliance to see which of the two methods would best characterize the severity of pulmonary disease. There was a significant correlation between radiological score and compliance (rsub(s)=-0.5776, n=55, p=0.001). Healthy newborns, newborns with RDS who did not need artificial ventilation and those newborns who needed respirator treatment had significantly different values of radiological score and compliance. RDS may be differentiated into groups of diagnoses. New-borns with HMD could be separated from those with wet lung syndrome or aspiration pneumonia by analyzing the radiogram or measuring the compliance. When survivors are compared with those newborns who died, the static respiratory compliance alone could predict the final outcome. (orig.)

  5. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  6. Comparison of chest radiography and high-resolution computed tomography findings in early and low-grade coal worker's pneumoconiosis

    Energy Technology Data Exchange (ETDEWEB)

    Savranlar, A.; Altin, R.; Mahmutyazicioglu, K.; Ozdemir, H.; Kart, L.; Ozer, T.; Gundogdu, S. [Zonguldak Karaelmas University, Zonguldak (Turkey). Faculty of Medicine

    2004-08-01

    High-resolution computed tomography (HRCT) is more sensitive than chest X-ray (CXR) in the depiction of parenchymal abnormalities. The paper presents and compares CXR and HRCT findings in coal workers with and without early and low-grade coal worker's pneumoconiosis (CWP). 71 coal workers were enrolled in the study. HRCT's were graded according to Hosoda and Shida's Japanese classification. After grading, 67 workers with CXR profusion 0/0-2/2 were included in the study. Four patients with major opacity were excluded. Profusion 0/1 to 1/1 cases were accepted as early and profusion and 2/2 cases as low-grade pneumoconiosis. Discordance rate was found to be higher in the early pneumoconiosis cases with negative CXR than low-grade pneumoconiosis (60, 36 and 8%, respectively). When coal miners with normal CXR were evaluated by HRCT, six out of 10 cases were diagnosed as positive. In low-grade pneumoconiosis group, the number of patients with positive CXR but negative HRCT were low in comparison to patients with CXR negative and early pneumoconiosis findings. Most of the CXR category 0 patients (10/16) were diagnosed as category 1 by HRCT. Eleven cases diagnosed as CXR category 1 were diagnosed as category 0 (7/11) and category 2 (4/11) by HRCT. In CXR category 2 (eight cases), there were four cases diagnosed as category 1 by HRCT. Overall, discordance between CXR and HRCT was high, especially for CXR negative and early pneumoconiosis cases. The role of CXR in screening coal workers to detect early pneumoconiosis findings should be questioned. The authors suggest using HRCT as a standard screening method instead of CXR to distinguish between normal and early pneumoconiosis.

  7. Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

    International Nuclear Information System (INIS)

    Siewerdsen, Jeffrey H.

    2011-01-01

    The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions-for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical performance under CBCT guidance, and early clinical trials demonstrate feasibility, workflow, and image quality within the surgical theatre.

  8. Quantitative image quality evaluation of pixel-binning in a flat-panel detector for x-ray fluoroscopy

    International Nuclear Information System (INIS)

    Srinivas, Yogesh; Wilson, David L.

    2004-01-01

    X-ray fluoroscopy places stringent design requirements on new flat-panel (FP) detectors, requiring both low-noise electronics and high data transfer rates. Pixel-binning, wherein data from more that one detector pixel are collected simultaneously, not only lowers the data transfer rate but also increases x-ray counts and pixel signal-to-noise ratio (SNR). In this study, we quantitatively assessed image quality of image sequences from four acquisition methods; no-binning and three types of binning; in synthetic images using a clinically relevant task of detecting an extended guidewire in a four-alternative forced-choice paradigm. Binning methods were conventional data-line (D) and gate-line (G) binning, and a novel method in which alternate frames in an image sequence used D and G binning. Two detector orientations placed the data lines either parallel or perpendicular to the guide wire. At a low exposure of 0.6 μR (1.548x10 -10 C/kg) per frame, irrespective of detector orientation, D binning with its reduced electronic noise was significantly (p -10 C/kg) per frame, with data lines parallel to the guidewire, detection with D binning was significantly (p<0.1) better than G binning. However, with data lines perpendicular to the guidewire, G binning was significantly (p<0.1) better than D binning because the partial area effect was reduced. Alternate binning was the best binning method when results were averaged over both orientations, and it was as good as the best binning method at either orientation. In addition, at low and high exposures, alternate binning gave a temporally fused image with a smooth guidewire, an important image quality feature not assessed in a detection experiment. While at high exposure, detection with no binning was as good, or better, than the best binning method, it might be impractical at fluoroscopy imaging rates. A computational observer model based on signal detection theory successfully fit data and was used to predict effects of similar acquisition methods. Results from this study suggest the use of exposure-dependent detector binning in fluoroscopy that switches between D binning and alternate binning at low and high exposures, respectively

  9. Single-layer and dual-layer contrast-enhanced mammography using amorphous selenium flat panel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Allec, N; Abbaszadeh, S; Karim, K S, E-mail: nallec@uwaterloo.ca [Department of Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West, Waterloo N2L 3G1 (Canada)

    2011-09-21

    The accumulation of injected contrast agents allows the image enhancement of lesions through the use of contrast-enhanced mammography. In this technique, the combination of two acquired images is used to create an enhanced image. There exist several methods to acquire the images to be combined, which include dual energy subtraction using a single detection layer that suffers from motion artifacts due to patient motion between image acquisition. To mitigate motion artifacts, a detector composed of two layers may be used to simultaneously acquire the low and high energy images. In this work, we evaluate both of these methods using amorphous selenium as the detection material to find the system parameters (tube voltage, filtration, photoconductor thickness and relative intensity ratio) leading to the optimal performance. We then compare the performance of the two detectors under the variation of contrast agent concentration, tumor size and dose. The detectability was found to be most comparable at the lower end of the evaluated factors. The single-layer detector not only led to better contrast, due to its greater spectral separation capabilities, but also had lower quantum noise. The single-layer detector was found to have a greater detectability by a factor of 2.4 for a 2.5 mm radius tumor having a contrast agent concentration of 1.5 mg ml{sup -1} in a 4.5 cm thick 50% glandular breast. The inclusion of motion artifacts in the comparison is part of ongoing research efforts.

  10. Single-layer and dual-layer contrast-enhanced mammography using amorphous selenium flat panel detectors

    Science.gov (United States)

    Allec, N.; Abbaszadeh, S.; Karim, K. S.

    2011-09-01

    The accumulation of injected contrast agents allows the image enhancement of lesions through the use of contrast-enhanced mammography. In this technique, the combination of two acquired images is used to create an enhanced image. There exist several methods to acquire the images to be combined, which include dual energy subtraction using a single detection layer that suffers from motion artifacts due to patient motion between image acquisition. To mitigate motion artifacts, a detector composed of two layers may be used to simultaneously acquire the low and high energy images. In this work, we evaluate both of these methods using amorphous selenium as the detection material to find the system parameters (tube voltage, filtration, photoconductor thickness and relative intensity ratio) leading to the optimal performance. We then compare the performance of the two detectors under the variation of contrast agent concentration, tumor size and dose. The detectability was found to be most comparable at the lower end of the evaluated factors. The single-layer detector not only led to better contrast, due to its greater spectral separation capabilities, but also had lower quantum noise. The single-layer detector was found to have a greater detectability by a factor of 2.4 for a 2.5 mm radius tumor having a contrast agent concentration of 1.5 mg ml-1 in a 4.5 cm thick 50% glandular breast. The inclusion of motion artifacts in the comparison is part of ongoing research efforts.

  11. Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

    Energy Technology Data Exchange (ETDEWEB)

    Siewerdsen, Jeffrey H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Traylor Building, Room 718, 720 Rutland Avenue, Baltimore, MD 21205 (United States)

    2011-08-21

    The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions-for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in surgical performance under CBCT guidance, and early clinical trials demonstrate feasibility, workflow, and image quality within the surgical theatre.

  12. Flat-panel detector volumetric CT for visualization of subarachnoid hemorrhage and ventricles: preliminary results compared to conventional CT

    International Nuclear Information System (INIS)

    Doelken, M.; Struffert, T.; Richter, G.; Engelhorn, T.; Doerfler, A.; Nimsky, C.; Ganslandt, O.; Hammen, T.

    2008-01-01

    The aim of this study was to compare flat-panel volumetric CT (VCT) to conventional CT (cCT) in the visualization of the extent of subarachnoid hemorrhage (SAH) and the width of the ventricles in patients with acute SAH. Included in the study were 22 patients with an acutely ruptured cerebral aneurysm who received VCT during coil embolization. VCT image quality, the extent of SAH (using a modified Fisher score and total slice number with SAH visible) and the width of the ventricles (Evans index) were evaluated by two experienced neuroradiologists (RAD1 and RAD2) and compared to the findings on cCT. Ten patients undergoing VCT for reasons other than SAH served as negative controls. Interobserver agreement in rating image quality was excellent for cCT (Kendall W value 0.94) and good for VCT (0.74). SAH was identified by RAD1 and RAD2 on VCT images in all patients. The modified Fisher scores underestimated the extent of SAH on VCT images in comparison with cCT images. Pearson's correlation coefficient (r) regarding the number of image slices with SAH visible on cCT images compared with the number on VCT images was 0.85 for RAD1 and 0.84 for RAD2. The r value for the degree of interobserver agreement for the number of slices with SAH visible was 0.99 for cCT, and 0.95 for VCT images (n 19), respectively. The width of the ventricles measured in terms of the Evans Index showed excellent concordance between the modalities (r = 0.81 vs. 0.82). Our preliminary results indicate that VCT is helpful in evaluating SAH in the angiography suite. Additionally, reliable evaluation of ventricle width is feasible. However, there are limitations with regard to the visibility of SAH on VCT images in comparison to cCT images. (orig.)

  13. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    International Nuclear Information System (INIS)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi

    2003-01-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  14. Regionally adaptive histogram equalization of the chest

    International Nuclear Information System (INIS)

    Sherrier, R.H.; Johnson, G.A.

    1986-01-01

    Advances in digital chest radiography have resulted in the acquisition of high-quality digital images of the human chest. With these advances, there arises a genuine need for image processing algorithms, specific to chest images. The author has implemented the technique of histogram equalization, noting the problems encountered when it is adapted to chest images. These problems have been successfully solved with a regionally adaptive histogram equalization method. Histograms are calculated locally and then modified according to both the mean pixel value of a given region and certain characteristics of the cumulative distribution function. The method allows certain regions of the chest radiograph to be enhanced differentially

  15. Digital radiography

    International Nuclear Information System (INIS)

    Zani, M.L.

    2002-01-01

    X-ray radiography is a very common technique used to check the homogeneity of a material or the inside of a mechanical part. Generally the radiation that goes through the material to check, produced an image on a sensitized film. This method requires time because the film needs to be developed, digital radiography has no longer this inconvenient. In digital radiography the film is replaced by digital data and can be processed as any computer file. This new technique is promising but its main inconvenient is that today its resolution is not so good as that of film radiography. (A.C.)

  16. The advantages of digital radiography in department of radiology

    International Nuclear Information System (INIS)

    Mao Lijuan; Luo Xiaomei; Wu Tengfang

    2009-01-01

    Objective: To investigate the advantages of digital radiography in department of radiology by comparing digital radiography with common radiography. Methods: Test card was used for testing the spatial resolution of DR and common radiography. 1000 films of chest by DR and 1000 films of chest by common radiography were compared in image quality, dose of radiation, the rate of waste film, and the advantages of DR was analyzed. Results: Compared to common radiography, DR had a high sensitivity, high DQE (quantum detection efficiency), high spatial resolution and density resolution. The speed of acquisition and X-ray conversion efficiency were fast. The function of post-processing was strong and the rate of disease detection was high. Conclusion: DR is better than common radiography in all respects, it will be widely applied. (authors)

  17. Image quality of a Konica Regius 336 digital system in chest radiography; Qualita' dell'immagine di un sistema digitale Konica Regius 336 per radiologia toracica

    Energy Technology Data Exchange (ETDEWEB)

    Ostinelli, A.; Frigerio, M.; Monti, A.F.; Gelosa, S.; Tognoli, P.; Perniola, N. [Azienda Ospedaliera S. Anna, Como (Italy). Servizio di Fisica Sanitaria; Gozzi, G. [Azienda Ospedaliera S. Anna, Como (Italy). Servizio di Radiologia

    2000-06-01

    Digital radiographic systems permit to optimize execution, depiction and storage of radiological images. Since a Regius 336 digital system (Konica Corp. Tokyo, Japan) devoted to chest radiography Department of S. Anna Hospital in Como, Italy, it was investigated its performance relative to image quality. Konica Regius 336 is a computed radiography system made of a phosphorescence detector plate which is scanned with an infrared semiconductor laser beam. The radiographic image obtained from the detector is subjected to image processing, which allows a stable output and the nonlinear curve typical of conventional radiographic systems. Image quality was assessed based on the following parameters: dose, contrast, noise and spatial resolution. As reference, it was assessed the same parameters on a Cronex 88 analogic chest-changer (DuPont Pharma, North Billerica, Mass, USA). The Regius 336 air kerma values were always higher than the analogic ones (about 10%), both with and without a chest phantom; noise was also greater than in analogic images, sometimes even doubled. The optical densities of a step wedge and the spatial resolution of the digital chest-changer are independent of the X-ray tube voltage consequent to broader optical latitude. Inversely, the analogic images of the wedges show great optical density variability as a function of the X-ray tube voltage (in a range of 2). The modulation transfer functions of the two systems have the same trend. The performance of the Konica Regius 336 is nearly equivalent to that of an analogic system. The main advantages of the digital system are a standard output, lower consumption of radiographic films, higher productiveness and better image quality standard level. [Italian] I sistemi radiografici digitali offrono la possibilita' di ottimizzare l'esecuzione, la visualizzazione e l'archiviazione dell'immagine radiologica. Poiche' presso il Servizio di Radiologia dell'Azienda Ospedaliera S. Anna

  18. Military radiography

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Historic military uses of radiography are discussed in this chapter: Battle of Adowa in 1986 was the first. Besides describing the early campaigns in which radiography was used, the author discusses the problems faced: a reliable source of electricity; the problems of extreme heat; moving and breakage of equipment. Numerous historical photographs are included. 9 refs

  19. Development of a prototype chest digital tomosynthesis (CDT) R/F system with fast image reconstruction using graphics processing unit (GPU) programming

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunghoon, E-mail: choi.sh@yonsei.ac.kr [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Lee, Seungwan [Department of Radiological Science, College of Medical Science, Konyang University, 158 Gwanjeodong-ro, Daejeon, 308-812 (Korea, Republic of); Lee, Haenghwa [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Lee, Donghoon; Choi, Seungyeon [Department of Radiation Convergence Engineering, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Shin, Jungwook [LISTEM Corporation, 94 Donghwagongdan-ro, Munmak-eup, Wonju (Korea, Republic of); Seo, Chang-Woo [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Kim, Hee-Joung, E-mail: hjk1@yonsei.ac.kr [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Department of Radiation Convergence Engineering, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of)

    2017-03-11

    Digital tomosynthesis offers the advantage of low radiation doses compared to conventional computed tomography (CT) by utilizing small numbers of projections (~80) acquired over a limited angular range. It produces 3D volumetric data, although there are artifacts due to incomplete sampling. Based upon these characteristics, we developed a prototype digital tomosynthesis R/F system for applications in chest imaging. Our prototype chest digital tomosynthesis (CDT) R/F system contains an X-ray tube with high power R/F pulse generator, flat-panel detector, R/F table, electromechanical radiographic subsystems including a precise motor controller, and a reconstruction server. For image reconstruction, users select between analytic and iterative reconstruction methods. Our reconstructed images of Catphan700 and LUNGMAN phantoms clearly and rapidly described the internal structures of phantoms using graphics processing unit (GPU) programming. Contrast-to-noise ratio (CNR) values of the CTP682 module of Catphan700 were higher in images using a simultaneous algebraic reconstruction technique (SART) than in those using filtered back-projection (FBP) for all materials by factors of 2.60, 3.78, 5.50, 2.30, 3.70, and 2.52 for air, lung foam, low density polyethylene (LDPE), Delrin{sup ®} (acetal homopolymer resin), bone 50% (hydroxyapatite), and Teflon, respectively. Total elapsed times for producing 3D volume were 2.92 s and 86.29 s on average for FBP and SART (20 iterations), respectively. The times required for reconstruction were clinically feasible. Moreover, the total radiation dose from our system (5.68 mGy) was lower than that of conventional chest CT scan. Consequently, our prototype tomosynthesis R/F system represents an important advance in digital tomosynthesis applications.

  20. Digital radiography

    International Nuclear Information System (INIS)

    Kusano, Shoichi

    1993-01-01

    Firstly, from an historic point of view, fundamental concepts on digital imaging were reviewed to provide a foundation for discussion of digital radiography. Secondly, this review summarized the results of ongoing research in computed radiography that replaces the conventional film-screen system with a photo-stimulable phosphor plate; and thirdly, image quality, radiation protection, and image processing techniques were discussed with emphasis on picture archiving and communication system environment as our final goal. Finally, future expansion of digital radiography was described based on the present utilization of computed tomography at the National Defense Medical College Hospital. (author) 60 refs

  1. Chest MRI

    Science.gov (United States)

    ... resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI Patient Instructions ... Gotway MB, Panse PM, Gruden JF, Elicker BM. Thoracic radiology. In: Broaddus VC, Mason RJ, Ernst JD, et ...

  2. Neutron radiography

    International Nuclear Information System (INIS)

    Bayon, G.

    1989-01-01

    Neutronography or neutron radiography, a non-destructive test method which is similar in its principle to conventional X-ray photography, presently occupies a marginal position among non-destructive test methods (NDT) (no source of suitable performance or cost). Neutron radiography associated with the ORPHEE reactor permits industrial testing; it can very quickly meet a cost requirement comparable to that of conventional test methods. In 1988, 2500 parts were tested on this unit [fr

  3. Industrial radiography

    International Nuclear Information System (INIS)

    1994-01-01

    This Health and Safety Executive Information Sheet on industrial radiography aims to inform directors and managers of industrial radiography companies on the safety precautions necessary to ensure that their personnel do not exceed dose guidelines for exposure to ionizing radiation. The Ionising Radiations Regulations 1985 (IRR85) require that exposure doses for radiographers are kept as low reasonably practicable. Equipment maintenance, and the employment of proper emergency procedures will help to ensure personnel safety. (UK)

  4. Pediatric digital chest imaging.

    Science.gov (United States)

    Tarver, R D; Cohen, M; Broderick, N J; Conces, D J

    1990-01-01

    The Philips Computed Radiography system performs well with pediatric portable chest radiographs, handling the throughout of a busy intensive care service 24 hours a day. Images are excellent and routinely provide a conventional (unenhanced) image and an edge-enhanced image. Radiation dose is decreased by the lowered frequency of repeat examinations and the ability of the plates to respond to a much lower dose and still provide an adequate image. The high quality and uniform density of serial PCR portable radiographs greatly enhances diagnostic content of the films. Decreased resolution has not been a problem clinically. Image manipulation and electronic transfer to remote viewing stations appear to be helpful and are currently being evaluated further. The PCR system provides a marked improvement in pediatric portable chest radiology.

  5. Pediatric digital chest imaging

    International Nuclear Information System (INIS)

    Tarver, R.D.; Cohen, M.; Broderick, N.J.; Conces, D.J. Jr.

    1990-01-01

    The Philips Computed Radiography system performs well with pediatric portable chest radiographs, handling the throughout of a busy intensive care service 24 hours a day. Images are excellent and routinely provide a conventional (unenhanced) image and an edge-enhanced image. Radiation dose is decreased by the lowered frequency of repeat examinations and the ability of the plates to respond to a much lower dose and still provide an adequate image. The high quality and uniform density of serial PCR portable radiographs greatly enhances diagnostic content of the films. Decreased resolution has not been a problem clinically. Image manipulation and electronic transfer to remote viewing stations appear to be helpful and are currently being evaluated further. The PCR system provides a marked improvement in pediatric portable chest radiology

  6. Industrial radiography

    International Nuclear Information System (INIS)

    1992-01-01

    Industrial radiography is a non-destructive testing (NDT) method which allows components to be examined for flaws without interfering with their usefulness. It is one of a number of inspection methods which are commonly used in industry to control the quality of manufactured products and to monitor their performance in service. Because of its involvement in organizing training courses in all the common NDT methods in regional projects in Asia and the Pacific and Latin America and the Caribbean and in many country programmes, the Agency is aware of the importance of standardizing as far as possible the syllabi and training course notes used by the many experts who are involved in presenting the training courses. IAEA-TECDOC-628 ''Training Guidelines in Non-destructive Testing'' presents syllabi which were developed by an Agency executed UNDP project in Latin America and the Caribbean taking into account the developmental work done by the International Committee for Non-destructive Testing. Experience gained from using the radiography syllabi from TECDOC-628 at national and regional radiography training courses in the Agency executed UNDP project in Asia and the Pacific (RAS/86/073) showed that some guidance needed to be given to radiography experts engaged in teaching at these courses on the material which should be covered. The IAEA/UNDP Asia and Pacific Project National NDT Coordinators therefore undertook to prepare Radiography Training Course Notes which could be used by experts to prepare lectures for Level 1,2 and 3 radiography personnel. The notes have been expanded to cover most topics in a more complete manner than that possible at a Level 1, 2 or 3 training course and can now be used as source material for NDT personnel interested in expanding their knowledge of radiography. Refs, figs and tabs

  7. Dental radiography

    International Nuclear Information System (INIS)

    Shekhdar, J.

    1993-01-01

    Dental radiography must comply with the same regulations with which conventional radiography complies. Radiation doses to individual patients are low but, because of the large number of patients X-rayed, the collective dose to the population is not negligible. Care in siting and regular maintenance of the equipment will reduce doses to both staff and patients. To produce X-ray films with a good image quality using a low radiation dose requires attention to film processing; this is often a neglected area. (Author)

  8. Industrial radiography

    International Nuclear Information System (INIS)

    Aloni, A.; Magal, O.

    1992-02-01

    This publication is meant to be a manual for industrial radiography. As such the manual concentrates on the practical aspects, presenting existing radiographic system and techniques of operation to satisfy specified quality requirements. The manual also reviews the safety aspect of performing radiographic work. (author) systems

  9. Radiography technique

    Energy Technology Data Exchange (ETDEWEB)

    Panaiotov, L N

    1951-10-23

    A new method of hollow articles radiography is presented enabling to eliminate shortcomings coupled with medical personnel irradiation when the ampoule incorporating radioactive substance is removed from the protective container and adjusted in the article. The method presented permits to transport the ampoule from the protective container immediately into the inner cavity of the article.

  10. Skull Radiography

    Science.gov (United States)

    What you need to know about… Skull Radiography X-ray images of the skull are taken when it is necessary to see the cranium, facial bones or jaw bones. ... Among other things, x-ray exams of the skull can show fractures. Patient Preparation Before the examination, ...

  11. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  12. FLAIL CHEST

    Directory of Open Access Journals (Sweden)

    Anton Crnjac

    2003-12-01

    Full Text Available Background. Major thoracic trauma is consistent with high mortality rate because of associated injuries of vital thoracic organs and dangerous complications. The flail chest occurs after disruption of the skeletal continuity of chest wall and demands because of its pathophysiological complexity rapid and accurate diagnosis and treatment.Conclusions. Basic pathophysiological mechanism of the flail chest is respiratory distress, which is provoked by pulmonary contusions and paradoxical chest wall motion. The treatment should be pointed to improvement and support of respiratory functions and include aggressive pain control, pulmonary physiotherapy and selective mechanical ventilation. Views about operative fixation of the flail chest are still controversial. Neither mortality rate neither long-term disability are improved after operative fixation.

  13. An audit of 3859 preadmission chest radiographs of apparently ...

    African Journals Online (AJOL)

    Background: Chest radiographs are routinely requested as part of the medical screening process prior to admission to institutions. Literature on the yield of such an exercise is sparse especially in the Nigerian setting. This study was therefore carried out to assess the usefulness of routine chest radiography for students at ...

  14. Progress in digital radiography

    International Nuclear Information System (INIS)

    Cappelle, A.

    2016-01-01

    Because of its practical aspect digital radiography is more and more used in the industrial sector. There are 2 kinds of digital radiography. First, the 'computed radiography' that uses a photon-stimulated screen, and after radiation exposure this screen must be read by an analyser to get a digit image. The second type is the 'direct radiography' that allows one to get a digit radiograph of the object directly. Digital radiography uses the same radioactive nuclides as radiography with silver films: cobalt, iridium or selenium. The spatial resolution of digital radiography is less good than with classical silver film radiography but digital radiography offers a better visual contrast. (A.C.)

  15. Technical characterization of five x-ray detectors for paediatric radiography applications

    Science.gov (United States)

    Marshall, N. W.; Smet, M.; Hofmans, M.; Pauwels, H.; De Clercq, T.; Bosmans, H.

    2017-12-01

    Physical image quality of five x-ray detectors used in the paediatric imaging department is characterized with the aim of establishing the range/scope of imaging performance provided by these detectors for neonatal imaging. Two computed radiography (CR) detectors (MD4.0 powder imaging plate (PIP) and HD5.0 needle imaging plate (NIP), Agfa HealthCare NV, B-2640 Mortsel, Belgium) and three flat panel detectors (FPD) (the Agfa DX-D35C and DX-D45C and the DRX-2530C (Carestream Health Inc., Rochester, NY 14608, USA)) were assessed. Physical image quality was characterized using the detector metrics given by the International Electrotechnical Commission (IEC 62220-1) to measure modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) using the IEC-specified beam qualities of RQA3 and RQA5. The DQE was evaluated at the normal operating detector air kerma (DAK) level, defined at 2.5 µGy for all detectors, and at factors of 1/3.2 and 3.2 times the normal level. MTF curves for the different detectors were similar at both RQA3 and RQA5 energies; the average spatial frequency for the 50% point (MTF0.5) at RQA3 was 1.26 mm-1, with a range from 1.20 mm-1 to 1.37 mm-1. The DQE of the NIP CR compared to the PIP CR was notably greater and similar to that for the FPD devices. At RQA3, average DQE for the FPD and NIP (at 0.5 mm-1 2.5 µGy) was 0.57 compared to 0.26 for the PIP CR. At the RQA5 energy, the DRX-2530C and the DX-D45C had the highest DQE (~0.6 at 0.5 mm-1 2.5 µGy). Noise separation analysis using the polynomial model showed higher electronic noise for the DX-D35C and DRX-2530C detectors; this explains the reduced DQE seen at 0.7 µGy/image. The NIP CR detector offers notably improved DQE performance compared to the PIP CR system and a value similar to the DQE for FPD devices at the RQA3 energy.

  16. Digital radiography

    International Nuclear Information System (INIS)

    Brody, W.R.

    1984-01-01

    Digital Radiography begins with an orderly introduction to the fundamental concepts of digital imaging. The entire X-ray digital imagining system is described, from an overall characterization of image quality to specific components required for a digital radiographic system. Because subtraction is central to digital radiographic systems, the author details the use of various subtraction methods for image enhancement. Complex concepts are illustrated with numerous examples and presented in terms that can readily be understood by physicians without an advanced mathematics background. The second part of the book discusses implementations and applications of digital imagining systems based on area and scanned detector technologies. This section includes thorough coverage of digital fluoroscopy, scanned projection radiography, and film-based digital imaging systems, and features a state-of-the-art synopsis of the applications of digital subtraction angiography. The book concludes with a timely assessment of anticipated technological advances

  17. Ambulating radiography

    International Nuclear Information System (INIS)

    Magnusson, K.

    1989-01-01

    Strong gamme or X-ray sources are utilized for non-destructive testing of i.e. bridges. The activities involve certain risks of accident that might lead to serious injuries caused by radiation. The National Institute of Radiation Protection has during the laste decade greatly yhe inspection rate in this area. It has today made controls of most enterprieses running ambulating radiography. (O.S.)

  18. Computed radiography

    International Nuclear Information System (INIS)

    Pupchek, G.

    2004-01-01

    Computed radiography (CR) is an image acquisition process that is used to create digital, 2-dimensional radiographs. CR employs a photostimulable phosphor-based imaging plate, replacing the standard x-ray film and intensifying screen combination. Conventional radiographic exposure equipment is used with no modification required to the existing system. CR can transform an analog x-ray department into a digital one and eliminates the need for chemicals, water, darkrooms and film processor headaches. (author)

  19. Magnification radiography

    International Nuclear Information System (INIS)

    Genant, H.K.; Resnick, D.

    1988-01-01

    The relative clinical value of magnification compared with conventional radiography for skeletal applications is presented qualitatively. The presentation is based on the authors' experience with over 25,000 cases in which magnification has been used. For most areas in which magnification (optical or geometric) proves useful, subtle abnormalities of clinical importance are present at bone surfaces or at host-lesion interfaces. This is particularly true for arthritis and metabolic and infectious disorders of bone. In additional instances, serial assessment of the progression of disease or its response to therapy is enhanced by magnification. When gross abnormalities are present, as in most instances of trauma and bone dysplasia, the findings are obvious on conventional radiography, and magnification is not necessary. Thus, the magnification techniques appear to provide important diagnostic information, depending upon the anatomic part that is studied and the clinical question that is posed. It is also apparent that the demonstration of subtle skeletal abnormalities to clinical colleagues for educational purposes is greatly enhanced by magnification radiography

  20. Investigation of the dosimetry of chest tomosynthesis

    Science.gov (United States)

    Svalkvist, Angelica; Zachrisson, Sara; Månsson, Lars Gunnar; Båth, Magnus

    2009-02-01

    Chest tomosynthesis has recently been introduced to healthcare as a low-dose alternative to CT or as a tool for improved diagnostics in chest radiography with only a modest increase in radiation dose to the patient. However, no detailed description of the dosimetry for this type of examination has been presented. The aim of this work was therefore to investigate the dosimetry of chest tomosynthesis. The chest tomosynthesis examination was assumed to be performed using a stationary detector and a vertically moving x-ray tube, exposing the patient from different angles. The Monte Carlo based computer software PCXMC was used to determine the effective dose delivered to a standard-sized patient from various angles using different assumptions of the distribution of the effective dose over the different projections. The obtained conversion factors between input dose measures and effective dose for chest tomosynthesis for different angular intervals were then compared with the horizontal projection. The results indicate that the error introduced by using conversion factors for the PA projection in chest radiography for estimating the effective dose of chest tomosynthesis is small for normally sized patients, especially if a conversion factor between KAP and effective dose is used.