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At least 397 records · Page 22Linked to original sources
PubMed2006

[Image quality and detection performance of a direct digital radiography system].

The physical characteristics of a direct amorphous Selenium (a-Se) digital fluoroscopy and radiography system were investigated. Pre-sampled modulation transfer functions (MTF) were measured using a slit method. Noise power spectra were determined for different input exposures by fast Fourier transform of uniformly exposed samples. The MTFs of direct digital radiography systems showed significantly higher values than those of indirect digital radiography and screen-film systems. The direct digital radiography systems showed higher noise levels compared with those of indirect systems under roughly the same exposure conditions. Contrast-detail analysis was performed to compare detection by direct digital radiography systems with that of the screen-film (FUJI HG-M2/UR2) systems. The average contrast-detail curves of digital and film images were obtained from the results of observation. Image quality figures (IQF) were also calculated from the individual observer performance tests. The results indicated that digital contrast-detail curves and IQF are, on average, are equal those of the screen-film system.

Fourier Analysis↗
PubMed1992

[An economic comparison between digital luminescence radiography and conventional film processing in intensive care medicine].

The costs of a conventional film-screen radiography daylight-system and storage-phosphor computed radiography (Fuji AC-1) are compared. In 1990, 3841 radiologic procedures (mostly portable chest X-rays) were performed in 3474 patients of a surgical intensive care unit. With conventional film-screen radiography 6.8% retakes were necessary for diagnostic or technical reasons. Comparing the fixed and variable costs of both systems conventional film-screen radiography was more economic under the given conditions of the test. It is concluded that computed radiography in intensive care patients has definite advantages in terms of image quality and reproducibility, however, in order to compete successfully in the economic turf CR has to be implemented in a picture archiving and communication system (PACS).

Costs and Cost Analysis↗
PubMedDate not supplied

Admission requirements for radiography programs.

CONTEXT: Radiography program applicants far outnumber available class capacity in many programs. Educational accountability requires that programs justify their admission practices, work to retain all qualified students and evaluate their attrition rates. Thus, radiography programs are interested in identifying the best candidates for admission. PURPOSE: The purpose of this small survey study was to document admission requirements of entry-level programs in radiography accredited by the Joint Review Committee on Education in Radiologic Technology (JRCERT) in Oklahoma and Texas. METHODS: A 14-question survey was sent to 45 JRCERT-accredited entry-level radiography programs in Oklahoma and Texas. The survey included questions concerning program demographics, admission criteria and admission practices. RESULTS: Cumulative grade point average, interviews, successful completion of math and science courses, and performance on standardized tests were the most commonly used admission criteria, although no criteria were used by all of the programs surveyed. CONCLUSION: The current study is the first step toward identifying the most effective admission criteria for radiography programs. Future research should examine the correlation of specific admission criteria with program success (ie, program retention, program completion and professional certification).

Educational Measurement↗
PubMed1988

[Dual-energy subtraction radiography of the breast].

Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, benign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses.

Breast Neoplasms↗
PubMed1993

[Cephalometry and digital radiography. Technical note].

Conventional and digital lateral teleradiographs of the skull were performed on 6 consecutive patients (3 men and 3 women). The study was aimed at comparing the diagnostic capabilities of the two imaging techniques to measure points and angles, as derived from different cephalometric analyses (see text for details). These variables were analyzed by three different operators: for both techniques, 18 cephalometric tracings were made, including a total of 414 points and 36 angles. Correlation coefficients between the two types of measurements (points and angles) were calculated; Wilcoxon's non-parametric test was also used. This study demonstrates digital radiography to be superior to conventional radiography to detect cephalometric landmarks, which is especially evident in the evaluation of the so-called "questionable" landmarks: the latter were 15 of 23 with conventional radiography and 9 of 23 with digital radiography. On the other hand, correlation coefficients and significance of the values of the considered angles were in close agreement with the two techniques. Therefore, its simultaneous demonstration of anatomical structures of different thickness--i.e., bone and soft tissues--and its lower exposure dose make digital radiography the diagnostic procedure of choice in cephalometrics, especially in the pediatric age, as well as in monitoring the patients.

Adolescent↗
PubMedDate not supplied

[Clinical use of magnification radiography in rheumatologic differential diagnosis].

Rheumatologic joint disorders were examined with high-definition microfocal magnification radiography. The magnification technique was compared to conventional radiographs (mammographic film-screen combinations). The microfocal x-ray unit had a spot size of 20-130 microns. Fourty patients with early arthritis (history of less than 18 months) were examined; x5 magnification was used. Digital luminescence radiography was employed to minimize radiation dose. Digital image processing included simulation of conventional technique and edge enhancement. Magnification radiographs and conventional technique were evaluated. In 20/40 patients articular lesions were detected. Magnification radiography gave additional information in 14/20 patients: in 5/14 patients lesions were seen only with magnification radiography (erosions n = 3, loss of the cortical white line n = 2), in 9/14 patients the extent of the lesions could be evaluated better. Hence, magnification radiography proved a valuable mean in early diagnosing and evaluating rheumatic disease.

Adolescent↗
PubMed2000

[Dose measurements comparing conventional and digital panoramic radiography].

OBJECTIVE: The purpose of our study was to measure and compare patient exposure by direct digital and conventional panoramic radiography. MATERIAL AND METHODS: Dose measurements were carried out on an anthropomorphic phantom, which was specially developed for dental radiography. Panoramic radiographs were taken with three different conventional devices (Orthopantomograph 10E, Orth Oralix FD, Siemens Orthophos) and two direct digital devices (Orthopantomograph 100 Digipan, Siemens Orthophos DS Ceph). The exposure conditions were according to clinical routine. The energy dose was measured at 28 places inside and on the surface of the phantom by using a set of 108 thermoluminescence detectors. Additionally, exposure time, tube voltage, central-beam dose, and dose-area products were measured. The effective doses were calculated on the basis of the absorbed doses. RESULTS: In each case, the highest energy doses were recorded at the parotid gland, the mandibular angle, the submandibular gland, and the skin in the neck. Panoramic radiographs taken with the conventional units yielded in effective doses in the range of 16-21 microSv, the digital units caused 5 or 14 microSv. CONCLUSION: In comparison with conventional techniques, patient exposure can be reduced by direct digital panoramic radiography. The extent of dose reduction depends on the device employed and is generally smaller than the dose reduction that can be achieved by digital imaging devices in intraoral radiography.

Humans↗
PubMed1998

Observer agreement in the detection of proximal caries with direct digital intraoral radiography.

OBJECTIVE: The aim of this study was to compare several values for consistency obtained by charged-coupled-device-based direct digital intraoral radiography with those obtained by conventional film-based radiography to evaluate observer agreement in determining the depth of proximal caries. STUDY DESIGN: A total of 93 proximal surfaces on radiologic images that were obtained by both the conventional film-based bite-wing technique and by direct digital intraoral radiography were evaluated by six observers. One of these observers also evaluated the same images six months after the initial evaluation. The kappa value, consistency ratio, agreement ratio, and Kendall's correlation coefficient were calculated for interobserver and intraobserver agreement. RESULTS: The overall kappa values for interobserver agreement were 0.439 and 0.424 in the direct digital system and the film-based radiography, respectively. The depth-related change of the values showed similar patterns in the two modalities for both interobserver and intraobserver agreement. CONCLUSION: The digital intraoral system resulted in no deterioration in observer agreement, and it presents no problems for clinical use with respect to the reliability of diagnosis.

Dental Caries↗
PubMed1999

Two- and three-dimensional imaging modalities for the detection of caries. A comparison between film, digital radiography and tuned aperture computed tomography (TACT).

OBJECTIVES: To compare the diagnostic performance provided by two- (film and digital radiography) and three-dimensional imaging modalities (TACT slices and TACT pseudoholograms) in the detection of primary caries. METHODS: Forty-two extracted human posterior teeth were mounted and imaged with conventional film and direct digital radiography. Free-hand positioning of a dental X-ray source was used for all exposures. From the digital images, iteratively restored TACT slices and TACT pseudoholograms were generated. Film images were viewed on a viewbox. Digital format images were viewed on a high-resolution monitor. Eight observers used a five-point scale to score the presence or absence of occlusal and proximal caries using the four image modalities. Observers' assessments were compared with the histological examination of tooth sections. Possible differences in ROC curve areas among image modalities, observers, and surfaces were assessed by ANOVA. Intra- and interobserver reliability as indicated by intraclass correlation was also calculated. RESULTS: There were no statistically significant differences between the diagnostic performances of film, digital radiography, TACT slices and TACT pseudoholograms in the detection of caries (P = 0.310). Intraclass correlation indicated the highest concordance both within and between observers when film was used for the evaluation. CONCLUSIONS: Under the experimental conditions of this study, three-dimensional TACT images did not improve caries detection over film or digital radiography. Further research should investigate the effects of imaging variables on TACT's diagnostic efficacy.

Analysis of Variance↗
PubMed1992

[Experiences with digital luminescence radiography (DLR) in pediatric radiology].

X-ray examinations represent a variety of indications with different demands on exposure latitude, spatial and contrast resolution of screen-film-system combinations in paediatric radiography. The value of digital luminescent radiography (DLR) was compared to conventional x-ray examinations carried out with screen-film-systems, speed class 200, by analysing matched digital and conventional exposures in 200 abdominal, 600 skeletal and 300 chest examinations. The exposure of DLR was reduced to 50% of conventional exposure. Analysing the results in abdominal and skeletal radiography, DLR proved to be diagnostically equivalent to conventional radiography despite the reduction in exposure dose. DLR of the newborn chest compared to conventional x-ray studies was not always sufficient due to lower digital spatial resolution.

Adolescent↗
PubMed1997

Direct digital radiography for the detection of periapical bone lesions: a clinical study.

The aim was to compare the observer performance of direct digital radiography, with and without image processing, with that of conventional radiography, for the detection of periapical bone lesions. For 50 patients, a conventional periapical radiograph using E-speed film was taken. Then, a direct digital image of the same area was made. The images presenting the periapical bone tissue of 59 roots were assessed by seven observers using a 5-point confidence scale. The digital images were first presented as original images, with default contrast and brightness set by the computer system. Following this, the observers were allowed to use the processing facilities for greyscale treatment. The results for original and processed direct digital images and for conventional radiographs were compared by Receiver Operating Characteristic (ROC) analysis. The area under the ROC curve, calculated as P(A) value, was 0.88 for conventional film, 0.82 for original digital images and 0.78 for processed images. Corresponding Az values were slightly higher, 0.89, 0.84 and 0.81. Statistically significant differences between ROC areas calculated as P(A) values for the methods were found. Comparison between Az values showed no significant differences between conventional radiographs and original digital images, whereas the difference between Az values for original and processed digital images was still significant. It was concluded that conventional film radiography performed slightly better for the detection of periapical bone lesions than direct digital radiography and that image processing did not improve the observer performance.

Alveolar Bone Loss↗
PubMed2003

Evaluating radiographic parameters for mobile chest computed radiography: phantoms, image quality and effective dose.

Conventional chest radiography is technically difficult because of wide variations in tissue attenuations in the chest and limitations of screen-film systems. Mobile chest radiography, performed bedside on hospital inpatients, presents additional difficulties due to geometric and equipment limitations inherent in mobile x-ray procedures and the severity of illness in the patients. Computed radiography (CR) offers a different approach for mobile chest radiography by utilizing a photostimulable phosphor. Photostimulable phosphors overcome some image quality limitations of mobile chest imaging, particularly because of the inherent latitude. Because they are more efficient in absorbing lower-energy x-rays than rare-earth intensifying screens, this study evaluated changes in kVp for improving mobile chest CR. Three commercially available systems were tested, with the goal of implementing the findings clinically. Exposure conditions (kVp and grid use) were assessed with two acrylic-and-aluminum chest phantoms which simulated x-ray attenuation for average-sized and large-sized adult chests. These phantoms contained regions representing the lungs, heart and subdiaphragm to allow proper CR processing. Signal-to-noise ratio (SNR) measurements using different techniques were obtained for acrylic and aluminum disks (1.9 cm diameter) superimposed in the lung and heart regions of the phantoms, where the disk thicknesses (contrast) were determined from disk visibility. Effective doses to the phantoms were also measured for these techniques. The results indicated that using an 8:1, 33 lines/cm antiscatter grid improved the SNR by 60-300 % compared with nongrid images, depending on phantom and region; however, the dose to the phantom also increased by 400-600%. Lowering x-ray tube potential from 80 to 60 kVp improved the SNR by 30-40%, with a corresponding increase in phantom dose of 40-50%. Increasing the potential from 80 to 100 kVp reduced both the SNR and the phantom dose by approximately 10%. The most promising changes in technique for trial in clinical implementation include using an antiscatter grid, especially for large patients, and potentially increasing kVp.

Humans↗
PubMedDate not supplied

Dual-energy subtraction chest radiography: what to look for beyond calcified nodules.

Dual-energy subtraction chest radiography is a robust and powerful tool that improves the ability to detect and accurately diagnose a wide variety of thoracic abnormalities on posteroanterior-lateral chest images. Dual-energy subtraction chest radiography has many advantages over conventional chest radiography that facilitate image interpretation. The major advantage of this imaging technique is that it more clearly depicts calcification, which greatly aids in characterizing pulmonary nodules. Dual-energy subtraction images are also helpful in the recognition of hilar and mediastinal masses; the detection of tracheal narrowing and vascular disease; the identification of bone, pleural, and chest wall abnormalities; and the localization of indwelling devices such as stents and catheters. However, dual-energy subtraction imaging also has some limitations of which the radiologist should be aware and requires a somewhat higher radiation dose than does conventional radiography.

Adult↗
PubMed1995

A comparison of detailed zonography with periapical radiography for the detection of periapical lesions.

The diagnostic accuracy of detailed zonography using the Scanora multimodal X-ray system was compared with that of periapical radiography. The study was based on the detection of periapical bone lesions at 259 dental sites distributed evenly throughout the dentitions of 164 patients. Each site was examined by periapical radiography and zonography, in parallel. The zonograms consisted of four detailed images that could also be read as stereopairs, in either the horizontal or vertical direction. Five observers evaluated the sites for the presence or absence of periapical osteolysis or sclerosis and apical widening of the periodontal ligament space for the whole dentition, and for three dental regions. ROC analysis revealed no significant overall or regional differences between the diagnostic accuracies of the periapical and zonographic techniques, regardless of whether the zonograms were read as sets of four images (multiview) or stereoscopic images. The sensitivity of periapical radiography was 72%, that of multiview zonography 88%, and that of stereoscopic zonography 85%. Specificities were 93%, 84% and 89%, respectively. The energy imparted during detailed zonography was 0.98 mJ. It is concluded that zonography is as good as periapical radiography for the detection of periapical pathology.

Adult↗
PubMed1996

Detailed tomography of periapical and periodontal lesions. Diagnostic accuracy compared with periapical radiography.

OBJECTIVE: To compare the diagnostic accuracy of detailed tomography using the Scanora system with that of conventional periapical radiography for detecting periapical and periodontal lesions. METHODS: We selected for comparison 243 periapical and 322 periodontal sites in 177 patients. Five observers independently assessed radiographs for the presence or absence of the following lesions: periapical bone changes, widening of apical and marginal ligament space, crestal erosion, vertical bone loss, furcation involvement and calculus. RESULTS: ROC analysis demonstrated no significant differences in the overall interpretation of either disease. Periapical radiography was superior (p < 0.05) to tomography for the detection of calculus. The sensitivity of tomography for periapical pathology was 87%, and 70% for periapical radiography. Sensitivities for periodontal diseases were 84% and 77%. Specificities were 81%, 90%, 77% and 79%, respectively. Differences for sensitivity and specificity were significant (p < 0.05) in relation to periapical pathology. The energy imparted during tomography was 0.92 mJ. CONCLUSION: Detailed tomography and periapical radiography performed equally well for the overall diagnosis of periapical and periodontal lesions. Tomograms differed substantially from periapical radiographs in both sensitivity and specificity for detecting periapical lesions in posterior regions. The energy imparted during detailed tomography is similar to that from two D-speed films.

Adult↗
PubMed1998

Practice patterns of radiologists and nonradiologists: nationwide Medicare data on the performance of chest and skeletal radiography and abdominal and pelvic sonography.

OBJECTIVE: We assessed the relative roles of radiologists and nonradiologists in performing chest and skeletal radiography and nonobstetric abdominal and pelvic sonography. MATERIALS AND METHODS: Information was extracted from the 1993 Medicare file on procedure volume for 65 imaging procedures. Claims were categorized by the specialty of the physician and the location (office or hospital) where the service was performed. RESULTS: In hospitals, radiologists performed virtually all chest and skeletal radiography and nonobstetric abdominal and pelvic sonography. In nonhospital settings such as offices or imaging centers, nonradiologists performed approximately two thirds of the chest and spinal radiography and nonobstetric abdominal and pelvic sonography and larger percentages (78-86%) of the pelvic, hip, lower extremity, and upper extremity radiography. CONCLUSION: Although radiologists perform virtually all chest and skeletal radiographs and abdominal and pelvic sonograms obtained in hospitals, they perform a distinct minority of these procedures in nonhospital settings. The data we present have certain implications for the amount of training nonradiologists receive in diagnostic imaging.

Bone and Bones↗
PubMed2003

Dual-energy chest radiography with a flat-panel digital detector: revealing calcified chest abnormalities.

OBJECTIVE: The aim of this study was to assess the value of dual-energy chest radiography obtained using a cesium iodide flat-panel detector in addition to standard posteroanterior chest radiography for the detection of calcified chest abnormalities. MATERIALS AND METHODS: The study included 20 patients with a total of 37 calcified chest lesions (16 pulmonary nodules, 17 mediastinal calcifications, and four pleural calcifications) as confirmed on CT. Twenty-eight locations in the chests of the same patients who were free of lesions were used as negative controls. Four radiologists reviewed posteroanterior chest radiographs in a blinded manner alone and in conjunction with dual-energy soft-tissue and bone images. We calculated sensitivity, specificity, the negative predictive value (NPV), and the positive predictive value (PPV) for lesion prediction. The Wilcoxon's and the Brunner and Langer's tests were performed for statistical analysis. RESULTS: For posteroanterior chest radiography, sensitivity was 36%, the PPV was 64%, and the NPV was 47%. When dual-energy images were added, sensitivity increased significantly to 66% (p < 0.05), the PPV to 76%, and the NPV to 62%. The specificity remained constant at 73%. Brunner and Langer's test revealed a highly significant difference between posteroanterior chest radiography and dual-energy imaging in the detection of calcified chest abnormalities (p < 0.01). CONCLUSION: Dual-energy images added to standard posteroanterior chest radiographs significantly improve the detection of calcified chest lesions.

Aged↗
PubMed2000

Effective and quality-controlled use of digital radiography in dental practice.

During the last years, the number of commercially available digital radiographic systems has increased rapidly. Nevertheless, they are hardly used in practice because several drawbacks still hinder dental practitioners from using digital radiography effectively in their routine work. In order to allow effective use of such systems in the dental practice, they must be integrated into the daily routine in an ergonomically optimal way and be driven by software following the rules of cognitive ergonomy and perception. The most important prerequisite for meaningful use of digital radiography in the dental practice is that it supports instead of disturbs daily clinical work. The underlying software should be easily comprehensible and intuitively applicable. This paper discusses advantages and disadvantages of digital compared to conventional radiography and how the introduction of digital radiography in dental practice affects clinical work. A concept is introduced that enables effective and quality-controlled use of digital radiographic systems in the dental practice by taking cognitive ergonomic aspects of the clinical work situation into account. This concept comprises the design of image databases for efficient storage and retrieval, the quality-controlled use of image manipulation methods adapted to the clinical requirements during diagnostic interpretation, and the usage of decision support systems for diagnosis and therapy of radiographic lesions.

Databases as Topic↗