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PubMed2004

[Dose exposure from analog and digital full mouth radiography and panoramic radiography].

The present study investigated the dose exposition in the head and neck region by use of analog and digital radiographic dental systems. Four radiographic devices were tested: panoramic radiography (analog and digital) and 14-image full-mouth-survey (FMS, analog and digital). Organ doses were measured on a Rando-phantom by use of CaF2-dosimeters according to the IRCP-guidelines and the effective doses calculated. The results were the following: the value of E was lowest in digital FMS (41 microSv) and highest in analog FMS (78 microSv), i.e. dose was reduced by 47% by using a digital device. In panoramic radiography, doses were 17% lower using digital technique (digital 45 microSv vs. analog 54 pSv). Thus, FMS is no longer associated with higher doses than orthopantomography when conventional films are replaced by digital techniques.

Humans↗

PubMed2006

Optimization of dose and image quality for computed radiography and digital radiography.

The surface doses to patients during chest, abdomen and pelvis radiography were measured over a period of 3 years, during which time computed radiography (CR) and digital radiography (DR) systems were introduced to replace film-screen systems. For film-screen and CR the surface doses were measured with thermoluminescent dosimeters. For DR the surface doses were calculated from the dose-area product (DAP) meter readings. Measurements were made for each type of examination and detector type on 10 average-size patients. Measurements were made immediately after the new systems were introduced, and subsequently as adjustments were made to optimize dose and image quality. Published diagnostic reference levels were used as target values in this optimization. Initially, CR doses were the same as or higher than for film-screen, and the doses were lower for DR compared to film-screen. Subsequent clinical experience with the systems led to changes in the technique used for chest examinations both for CR and for DR. For CR, it was possible to change the algorithm and decrease the dose to one quarter of the initial value with acceptable image quality. For DR, it was decided to reduce noise by increasing the dose by a factor of two. No changes were made to abdomen or pelvic imaging techniques for either CR or DR. The final patient surface doses using CR were similar to published diagnostic reference doses; for DR, all patient doses were less than published reference levels.

Algorithms↗

PubMed2000

Digital radiography of the skeleton using a large-area detector based on amorphous silicon technology: image quality and potential for dose reduction in comparison with screen-film radiography.

AIM: The purpose of this study was to evaluate a large-area, flat-panel X-ray detector (FD), based on caesium-iodide (CsI) and amorphous silicon (a-Si) with respect to skeletal radiography. Conventional images were compared with digital radiographs using identical and reduced radiation doses. MATERIALS AND METHODS: Thirty consecutive patients were studied prospectively using conventional screen-film radiography (SFR; detector dose 2.5 microGy). Digital images were taken from the same patients with detector doses of 2.5, 1.25 and 0.625 microGy, respectively. The active-matrix detector had a panel size of 43 x 43 cm, a matrix of 3 x 3K, and a pixel size of 143 microm. All hard copies were presented in a random order to eight independent observers, who rated image quality according to subjective quality criteria. Results were assessed for significance using the Student's t -test (confidence level 95%). RESULTS: A statistically significant preference for digital over conventional images was revealed for all quality criteria, except for over-exposure (detector dose 2.5 microGy). Digital images with a 50% dose showed a small, statistically not significant, inferiority compared with SFR. The FD-technique was significantly inferior to SFR at 75% dose reduction regarding bone cortex and trabecula, contrast and overall impression. No statistically significant differences were found with regard to over- and under-exposure and soft tissue presentation. CONCLUSION: Amorphous silicon-based digital radiography yields good image quality. The potential for dose reduction depends on the clinical query.

Aged↗

PubMed1993

Digital radiography versus conventional radiography for the detection of a skull fracture under varying exposure parameters.

RATIONALE AND OBJECTIVES: The effect of varying exposure parameters on the detectability of a fracture with digital and conventional radiography were examined. METHODS: A macerated fractured skull was imaged by film-screen radiography (FSR) and digital storage phosphor radiography (DR) with various exposure values. Five radiologists traced the course of a fracture line. The length of the fracture was reported and the results were analyzed by Student's t test for paired samples. RESULTS: At 35% of the conventional radiation dose, the standard DR screen displayed an average of 48% of the fracture length. The difference from the conventional image (45%) was not significant in this case. An increase of the dose to ten times the conventional dose (250 mAs) yielded no significant improvement in the detectability of the length of the fracture (51%). CONCLUSIONS: This experiment shows that with use of the DR with the standard screen, a dose reduction of approximately 35% appears to be possible without any resulting loss of image quality compared to FSR. Use of the high resolution screens should be avoided, since they require a higher incident image dose than standard screens without offering any diagnostic advantages. The image dose of digital radiographs can be roughly estimated based on the digital device sensitivity value. As a rule, the sensitivity value should range between 100 and 200.

In Vitro Techniques↗

PubMed2002

Flat panel digital radiography compared with storage phosphor computed radiography: assessment of dose versus image quality in phantom studies.

RATIONALE AND OBJECTIVE: To assess and quantify the dose reduction by use of a CsI-flat panel digital radiography (DR)-system compared with digital computed radiography (CR). MATERIALS AND METHODS: A TCDD-test using the CDRAD-phantom was performed at mAs-values of 5, 4, 2.5, 2, 1, and 0.5 mAs for both digital systems. Entrance surface doses were recorded for all images. Images were presented to four independent observers. For quantitative comparison the image quality figure (IQF) was calculated. Statistical analysis was performed using the Pearson correlation and the Wilcoxon test. A ROC analysis was performed using the TRG-phantom. Settings of 4, 2.5, 2 mAs for both systems were used. In addition, 1 and 0.5 mAs were used for the DR system only. Statistical significance was evaluated using Student test. RESULTS: The DR system provided equivalent results compared with CR with respect to high frequency information and superior results with respect to low contrast details. Compared with computed radiography, the flat panel detector demonstrated significantly lower IQFs, ensuring a better image quality with respect to contrast and detail detectability. IQFs for DR and CR were equal at a surface dose reduction of 87% for DR. ROC analysis revealed significantly higher values under the curve for DR up to a surface dose reduction of 70%. CONCLUSIONS: Image quality of DR proved to be far superior to CR in particular for low contrast details. The image quality of CR is similar to that of DR only at high dose levels.

Phantoms, Imaging↗

PubMedDate not supplied

Comparison of computed tomography, tangential view radiography, and conventional radiography in evaluation of canine pelvic trauma.

Thirteen dogs with fractures requiring surgical repair were evaluated by standard two-view (i.e., lateral and ventrodorsal) radiography, tangential view (ventro 20 degrees cranial-dorsocaudal [inlet] and ventro 20 degrees caudal-dorsocranial [outlet]) radiography, and computed tomography (CT). Radiographic and CT examinations were reviewed independently by the three authors, and specific anatomic sites were graded for the presence or possibility of lesions. The results of radiographic interpretations were compared to CT scan interpretations. Eighty-one percent of skeletal lesions detected by CT scans were diagnosed definitively radiographically. Differences between the interpretation of CT and radiographic examinations included abnormalities associated with soft-tissue structures (P < 0.0001), the sacroiliac joints (P = 0.02), and the acetabula (P = 0.04). Interpretation of the lateral/ventrodorsal and inlet/outlet radiographic series were not statistically different, although inlet views may be complimentary to the standard radiographic examination. Its use deserves further study. Reader variation was less on evaluation of CT examinations than radiographic examinations. CT multiplaner reformations and three-dimensional reconstructions were useful for surgical planning in seven dogs. CT scanning is superior to survey radiography in assessing skeletal and soft-tissue injuries in dogs with pelvic trauma, although all clinically significant surgical lesions were described accurately radiographically. Based on this small series, the routine CT examination of dogs with pelvic trauma may not be justifiable for diagnosis but may be advantageous for surgical planning, especially if acetabular fractures are suspected on radiographs.

Animals↗

PubMed1985

Emergency skull radiography: the effect of restrictive criteria on skull radiography and CT use.

A prospective study was performed to determine the effect of restrictive criteria on the use of emergency skull radiography and computed tomography (CT) of the head. Emergency skull radiography required the completion of a special requisition form. Emergency CT of the head was done at the request of senior consultants and was available on a full-time basis. Over 1 year, 2,758 skull studies were performed, a decrease of 39.1% when compared with the year before restrictive criteria were instituted, during which 4,587 skull examinations were done. In the same period, the number of emergency CT scans of the head increased by 45.7%, from 471 in the control year to 686 in the experimental year. With the use of restrictive criteria, a net savings of +164,000 was achieved. Our results suggest that the use of restrictive criteria is a cost-effective means of limiting skull radiography when CT of the head is readily available.

Adolescent↗

PubMed1989

[Pulmonary nodule detection of chest phantom with CRT images--comparison with conventional radiography (film-screen system) and FCR (Fuji Computed Radiography) hardcopy].

Conventional Radiography, Fuji Computed Radiography (FCR) hardcopy and CRT images were evaluated about the detectability of pulmonary nodule using the chest phantom. Conventional and digitized chest radiographs (FCR) were used, including 45 normal cases and 45 abnormal cases with a variety pulmonary nodule. Observer performance tests were conducted to compare the effects on diagnostic accuracy of Conventional Radiography, FCR hardcopy and CRT images, and diagnostic accuracy was determined with receiver operating characteristic (ROC) analysis. ROC study was performed in which six radiologists were asked to locate nodule on three modalities. Two CRT monitors were used to observed CRT images. The left side CRT monitor was divided into two parts and displayed two images which were done as same image processing as FCR hardcopy. The right side CRT monitor was divided into four parts and displayed four images as a subsidiary diagnosis. The upper two images were displayed to diagnose the nodule of cardiac and diaphragmatic area, and lower two images were displayed to diagnose the nodule of the lung field. The results were summarized as follows: 1) CRT images were superior in sensitivity (78.5%) to the others, and FCR hardcopys were superior in specificity (95.9%). 2) About the accuracy of 5 and 8 mm in diameter nodule detection, there was no significant difference among three modalities. 3) Diagnostic accuracy of 3 mm in diameter nodule detection was significantly greater with digitized radiographs (FCR 44.4%, CRT images 54.4%) than with conventional radiograph (17.7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

PubMed1994

Intraoral computed radiography using the Fuji computed radiography imaging plate. Correlation between image quality and reading condition.

The quality of images obtained by a new method of intraoral computed radiography using three types of imaging plates and a drum scanner designed exclusively for use with an imaging plate was investigated. The aperture size for reading of radiographic data from the imaging plate and for film recording was 50, 100, or 150 microns 2. The results indicated that high resolution type imaging plate for mammography produced the best image quality. For each imaging plate, it was also found that the image quality improved as the aperture size was decreased. However, the high resolution type IP even at the aperture size of 100 microns 2 showed diagnostic accuracy as high as the image processing of conventional periapical radiographs. This finding suggests that this new imaging system using an imaging plate at the reading and recording aperture size 100 microns 2 has promise for use in intraoral radiography.

Evaluation Studies as Topic↗

PubMed1994

Optimization of chest films of equalization radiography (advanced multiple beam equalization radiography). Comparison by means of a receiver operating characteristic study of simulated nodular interstitial disease.

RATIONALE AND OBJECTIVE: To optimize screen-film combinations for equalization radiography (advanced multiple beam equalization radiography [AMBER]), five different film-screen-technique combinations were compared by receiver operating characteristics study of simulated interstitial disease. MATERIALS AND METHODS: The Ortho C-Lanex Regular and the Insight Thoracic Imaging HC system were compared in conventional nonequalized technique; T-Mat G-Lanex Regular and T-Max L-Lanex Regular were compared in conventional, nonequalized, and AMBER technique; and an experimental high-contrast, low-noise, near-zero crossover film-screen combination was compared in AMBER technique. Interstitial disease was simulated by superimposing birdseed on the back of a humanoid phantom. Twenty-five posterior-anterior radiographs were made with each technique. Seven observers scored the presence of interstitial disease in each of the quadrants on a 5-point scale following receiver operating characteristic methodology. RESULTS: The highest performance was found with the experimental film-screen-AMBER combination (Az = 0.92) and the lowest with the T-Mat L-Lanex Regular-AMBER combination (Az = 0.83) and the Insight Thoracic Imaging HC system-conventional combination (Az = 0.85). T-Mat L-Lanex Regular-conventional ranked second (Az = 0.90) while T-Mat G-Lanex Regular-conventional (Az = 0.89), T-Mat L-Lanex Regular-AMBER (Az = 0.88) and Ortho-C-Lanex Regular-conventional (Az = 0.87) scored lower. CONCLUSION: Higher contrast films in AMBER improve diagnostic performance, whereas a loss of information is found if the AMBER system is combined with lower contrast films.

Humans↗

PubMed1992

Personal computer equipment for dental digital subtraction radiography vs. industrial computer equipment and conventional radiography.

A "low-cost" personal computer (PC) system used to digitize dental radiographs was tested by assessing the accuracy of its subtraction images versus those of "high-cost" industrial equipment and conventional radiography. Subtraction images were made of artificial lesions in human femur bone and subsequently evaluated by students and teachers. The observations were analyzed in terms of true positive and false positive reports. "Low-cost" and "high-cost" subtraction images revealed only small differences in diagnostic accuracy. Compared to conventional radiography, the diagnostic accuracy of the subtraction images with the "low-cost" PC system was significantly higher for all observers. The interexaminer variance was similar for the subtraction and the conventional images for both students and teachers, except for a significantly reduced interexaminer variance for the teachers concerning the true positive reports with the "low-cost" PC subtraction technique.

Bone and Bones↗

PubMed2000

Digital selenium radiography: anti-scatter grid for chest radiography in a clinical study.

The purpose of this study was to evaluate the diagnostic performance of an additional stationary anti-scatter grid in digital selenium radiography (DSR) compared with images acquired with only an air gap. Chest radiographs were obtained with DSR in 100 patients with and without an anti-scatter grid. Four observers scored 12 anatomical landmarks, catheters and wire cerclages for their visualization in both subsets of images. Statistical analysis was performed using a paired t-test. Anatomical landmarks, catheters and wire cerclages were statistically better visualized in regions of high attenuation when the images were performed with an anti-scatter grid. No statistically significant difference was noted for peripheral regions, nor for sex and weight of the patient between the two modalities. Therefore, an anti-scatter grid is not recommended for chest radiography as it increases the radiation exposure of patients without having a significant impact on visualization for all regions of the chest.

Adult↗

PubMed1996

A cost-analysis of computed radiography and picture archiving and communication systems in portable radiography.

A total of 40,000 portable examinations are performed each year at Shands Hospital (Gainesville, FL), a 570-bed teaching hospital. Radiographs are obtained using a screen-film combination with the films digitized for transmission to displays in four intensive care units. A cost-analysis of replacing screen-film with computed radiography (CR) integrated into a filmless picture archiving and communication system (PACS) network was performed. Equipment requirements included two CR units, three high-resolution dual monitor displays, and an archive to store 3 months of image data. The capital costs were amortized over a 5-year period. Capital and operating costs of the proposed expansion to the existing PACS network, together with anticipated cost savings, were determined. The maximum data transfer rate for portable examinations was 150 MByte per hour and approximately 400 GByte of image data are generated each year. These figures were used to determine the hardware requirements for handling the acquisition, transfer, and display of the images. Annual costs of the proposed expansion were about $220,000. Cost savings were achieved by elimination of film, including its handling by technologists/library clerks, and amounted to about $200,000 per year.

Adult↗

PubMed2003

[New computed radiography technologies in digital radiography].

Digital radiography (DR) has become integral to modern diagnostic radiology. One of the earliest forms of DR, computed radiography (CR) using storage phosphors, has established itself as the mainstay of DR-based diagnostic imaging over the past 20 years. More recently, flat-panel DR systems based on solid state X-ray detectors with integrated, large-area, active-matrix readout electronics are promising further improvements in clinical workflow and image quality. Despite CR's longevity, innovations continue to be made. New developments in CR screen technologies, like structured (needle) screens, and new scanner concepts based on line-at-a-time reading promise major improvements in image quality (comparable to that of flat-panel systems), system through-put and physical size, at a cost comparable to that of today's systems. Thus, despite the advent of flat-panel acquisition systems, there will still be an important role for CR in the foreseeable future. After a brief review of the current state of CR technology, this paper will explore several of these new CR developments and present some examples of their potential clinical impact.

Artifacts↗

PubMed1986

Dual-energy projection radiography using condenser x-ray generator and digital radiography apparatus.

The authors describe a system for dual-energy projection radiography using a modified condenser-type x-ray generator and a digital radiography unit. High- and low-energy images are obtained within a practical exposure interval. This method provides better visualization of soft tissues that are otherwise obscured by skeletal structures and also allows better visualization of bone and calcifications (e.g., calcified nodules in the lung) without interference by overlying soft tissue.

Humans↗

PubMed1989

Paraffin tissue block radiography: adjunct to breast specimen radiography.

Radiography of specimens is an essential step in confirming excision of nonpalpable breast lesions. On occasion, however, the pathologist may not identify the lesion histologically. The authors report five cases in which suspicious microcalcifications were included in the excised tissue but were not identified by the pathologist. In all five, paraffin tissue block radiography enabled identification of the specific blocks containing the microcalcifications. The correct tissue blocks were then sectioned again, and the microcalcifications were identified histopathologically. In one case, the initial diagnosis of intraductal hyperplasia was changed to intraductal carcinoma with focal invasion. When the pathologist cannot identify the calcifications on initial histopathologic sections, this technique may assist in identification of the mammographic abnormality.

Biopsy↗

PubMed1995

Volume detection threshold: quantitative comparison of computed radiography and screen-film radiography in detection of pneumothoraces in an animal model that simulates the neonate.

PURPOSE: To quantitatively compare computed radiography (CR) and screen-film radiography (SFR) in the detection of pneumothorax in an animal model that simulates the neonate. MATERIALS AND METHODS: Three rabbits underwent placement of 5-F catheters in the right pleural space. Eight CR and eight SFR images were obtained. Volume-controlled pneumothorax was induced by incrementally injecting 4 cm3 of air (24 cm3 total) and four CR and four SFR images were obtained after each injection. Four radiologists blindly viewed the images twice (eight readings per image, 1,600 total observations). A dichotomous yes-no score for the presence of pneumothorax was used to calculate the volume detection threshold (VDT), defined as the air volume at which 50% of the pneumothoraces can be detected. The authors plotted the likelihood of a pneumothorax against the air volume by using the confidence indicator. RESULTS: Intraobserver VDT values for CR and SFR were not significantly different. CONCLUSION: CR is as accurate as SFR in the detection of pneumothorax in this quantitative animal model.

Animals↗

PubMed1996

A study of dose reduction using digital luminescence radiography for lateral skull radiography.

For lateral skull radiography the minimum required radiation patient exposure to ensure adequate image quality was determined for digital luminescence radiography (DLR) in comparison with a screen-film system (speed class 200). Radiographs were produced with a grid technique on conventional X-ray equipment. A real prepared female head including a true fracture above the pars petrosa ossis temporalis was imaged. The tube current-time product (mAs), and thus the surface entrance dose, was varied systematically. Surface entrance dose was measured with TLD-100 rods. Image quality was judged by experienced radiologists according to the criteria: visual resolution, mean optical density, contrast and perceptibility of specific bone structures. Surface entrance dose was reduced from 0.46 to 0.20 mGy by application of DLR instead of speed class 200 screen-film system without loss of diagnostic information in clinical routine. This corresponds to a dose reduction potential of 57% showing a good agreement with the dose reduction potential of 52% obtained in a previous study using the Alderson head phantom.

Female↗