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At least 865 records · Page 48Linked to original sources
PubMed2001

Organ doses and subjective image quality of indirect digital panoramic radiography.

OBJECTIVES: To determine if slight variations in exposure will affect diagnostic image quality and absorbed radiation doses for digital and analogue panoramic radiography. METHODS: Thermoluminescent dosimeters were placed in the thyroid gland, eyes, submandibular glands, parotid glands and skin of two human cadaver heads. Three different exposure settings were used: 70 kV, 120 mAs; 77 kV, 75 mAs; and 81 kV, 60 mAs. Subjective image quality was assessed using a phantom head. Storage phosphor (SP) images were printed on film and both analogue and SP images were assessed for their subjective image quality on a five-point rating scale. The results were statistically analysed using logistic regression analysis and chi(2) tests. RESULTS: Highest organ doses were measured for the submandibular glands, followed by the parotid glands. Salivary gland doses tended to be higher at lower kV settings. Image quality was not statistically different for the different exposure settings. Imaging technique did not seem to influence diagnostic image quality, except for the periapical status of upper premolars where SP was better. The main reason for any differences appeared to be interobserver variation. CONCLUSIONS: Analogue and SP panoramic radiography performed equally well for subjective diagnostic image quality. No significant differences could be found at the exposure settings used in this study. Radiation doses were highest for the salivary glands, especially at lower kV settings.

Eye↗
PubMed2001

Dose reduction by direct-digital cephalometric radiography.

Patient radiation exposure was determined for conventional and direct-digital cephalometric radiography. An anthropomorphic phantom was positioned to expose lateral cephalographs from the patient's left side. The conventional radiographs were exposed with a Siemens Orthophos C unit (77 kV, 14 mA, 0.5 s) and a film-screen system of a relative speed of 400. The direct-digital radiographs were exposed with a Siemens Orthophos DS Ceph (73 kV, 15 mA, 15.8 s). A set of 108 thermoluminescence detectors (TLDs; Bicron STI/Harshaw, Solon, Ohio) was used for dose measurements. For each measurement, 84 TLDs were placed at the surface of the head and neck, as well as inside the phantom, at anatomically relevant positions. The remaining detectors were employed for calibration purposes and quality control. The highest absorbed doses were recorded for the conventional technique at the skin of the left parotid region (132 microGy), in the left parotid gland (103 microGy), and in the ocular lens of the left eye (81 microGy). Digital cephalometry resulted in an absorbed dose about 2 times lower than the dose received by the conventional technique. The effective doses had the same relation (conventional 2.3 microSv; digital 1.1 microSv). The results demonstrate that direct-digital cephalometric radiography cuts the patient's dose in half compared with the conventional screen-film technique. Direct-digital cephalometry is more advantageous than the conventional technique from the perspective of radiation protection.

Cephalometry↗
PubMed2003

Comparison of the diagnostic potential of direct digital and conventional intraoral radiography in the evaluation of peri-implant conditions.

The aims of this study were to examine whether viewers agreed on details seen in direct (real time) digital and conventional film radiographs of implants, and whether there were differences in agreement between the systems. Intra-oral radiographs of implants were exposed both as direct digital and conventional film radiographs. Fifty pairs of radiographs with similar projection and exposure were selected, showing 59 implants. Ten viewers assessed the radiographs separately and noted eight different details. The viewers showed very high agreement in their assessments of radiographs of each technique separately, and there were no statistically significant differences. However, there was a tendency to stronger agreement in the direct digital radiographs in four assessed points out of eight. The patients' experience of having radiographs exposed with the two methods was also studied by questionnaire. The patients' opinions on the two techniques did not differ statistically. This study shows that digital radiography has at least equal diagnostic yield compared to film radiography.

Adolescent↗
PubMed2002

Routine panoramic radiography of new adult patients in general dental practice: relevance of diagnostic yield to treatment and identification of radiographic selection criteria.

OBJECTIVES: We sought to measure the diagnostic yield of relevance to treatment on routine panoramic radiographs taken of new adult (ie, 18 years and over) patients in general dental practice. STUDY DESIGN: Routine panoramic radiographs (n = 1817) obtained from general dental practice were assessed and radiologic yield recorded using consensus viewing by 2 dental radiologists. A modified diagnostic yield of relevance to treatment for each radiograph was calculated by omission of findings that would have been identified on bilateral posterior bitewing radiographs and of radiologic findings of no relevance to treatment. Stepwise logistic regression analysis was used in attempt to identify clinical indicators of a high diagnostic yield of relevance to treatment. RESULTS: The diagnostic yield of relevance to treatment was zero for the majority (56%) of patients. This figure rose to 71% when the symptom-free patients were considered. Five clinical indicators for panoramic radiography were identified, as follows: clinical suspicion of teeth with periapical pathologic conditions, presence of partially erupted teeth, clinically evident caries lesions, swelling, and clinically suspected unerupted teeth. CONCLUSION: Routine panoramic radiography of adult dental patients is not supported by the results of this study. The use of clinical indicators to select patients may help to improve diagnostic yield.

Adult↗
PubMed2005

Effect of dose on image quality in a detector-based dual-exposure, dual-energy system for chest radiography.

PURPOSE: To assess the image quality of subtracted soft tissue and bone images of a CsI-detector-based dual-energy system for chest radiography at varying dose levels. MATERIAL AND METHODS: We evaluated a CsI-detector-based, dual-exposure, dual-energy prototype system; 126 patients were categorized into groups of small, medium, and large. Fixed values were applied for mAs and mA. The patients were randomized into two groups with intended higher and lower speed pairs of approximately 400/1000 (high and low energy shot) and 200/500, respectively. True speed equivalents were calculated retrospectively using the detector dose. Image quality was evaluated by two highly experienced radiologists in consensus applying a rating scale of 1 to 5 for quality indicators such as image noise, residual bone structures, motion artifacts, and others. RESULTS: Significantly decreased noise and a significant improvement for display of bone details in the bone image were noted with the higher dose, whereas a significant increase in motion artifacts reduced image quality at the higher dose. CONCLUSION: Radiation dose did not significantly influence the perception of dual-energy image quality. Dual-energy subtraction, as described, has the potential to become a future routine application in chest radiography.

Aged↗
PubMed2005

Dose-image quality optimisation in digital chest radiography.

A range of techniques has been developed in conventional radiography for the chest, because of technical difficulties in imaging the wide variation of tissue densities. These techniques can differ significantly in tube potential selection, for scatter reduction and in application of manual or automatic exposure control. In this study a geometric chest phantom designed to simulate a chest image, has been used to study image quality on an indirect digital radiography (DR) system. Relative values for the signal-to-noise ratio (SNR), have been derived from analysis of contrast detail objects within the lung, heart and subdiaphragm regions of the phantom. Results showing the variation in SNR and detail perception with tube potential are presented for three radiographic techniques: using a grid, an air gap and no scatter reduction. SNR measurements provided a useful objective measure for assessment of image quality for optimising DR systems.

Artifacts↗
PubMed2006

Dose optimisation in computed radiography.

After the installation of computed radiography (CR) systems in three hospitals in Luxembourg a patient dose survey was carried out for three radiographic examinations, thorax, pelvis and lumbar spine. It was found that the patient doses had changed in comparison with the patient doses measured for conventional radiography in the same three hospitals. A close collaboration between the manufacturers of the X-ray installations, the CR imaging systems and the medical physicists led to the discovery that the speed class with which each radiographic examination was to be performed, had been ignored, during installation of the digital imaging systems. A number of procedures were carried out in order to calibrate and program the X-ray installations in conjunction with the CR systems. Following this optimisation procedure, a new patient dose survey was carried out for the three radiographic examinations. It was found that patient doses for the three hospitals were reduced.

Humans↗
PubMed1989

Comparison of dual-energy and conventional chest radiography for nodule detection.

This paper presents the results of a nodule detection study, using a Humanoid chest phantom, which was designed to evaluate the performance of two types of dual-energy and conventional (single-energy) chest radiography. The film-screen apparatis were used as image detectors for all imaging modalities. The area under the ROC curve and the cumulative true-positive fraction both were used as performance indexes in the evaluation. Because of the small number of false-positive responses in the observer studies, the cumulative true-positive fraction was eventually regarded as a more conclusive index of accuracy than the area under the ROC curve to make a reasonable conclusion. Both dual-energy techniques, dual- and single-exposure, were found to be superior to conventional chest radiography, P less than 0.0005 and P less than 0.006 for dual- and single-exposure techniques, respectively. The difference between the two dual-energy techniques was statistically insignificant, P less than 0.47. We concluded that the dual-energy, single-exposure technique is worthy of further clinical study based on these encouraging results and because of the ease with which the technique can be implemented.

Humans↗
PubMed2002

Spinal cord injury without radiographic abnormality: results of the National Emergency X-Radiography Utilization Study in blunt cervical trauma.

BACKGROUND: The purpose of this study was to better define the incidence and characteristics of patients with spinal cord injury without radiographic abnormality (SCIWORA), using the database of the National Emergency X-Radiography Utilization Study (NEXUS). METHODS: This was a prospective, observational study of blunt trauma patients in 21 U.S. medical centers undergoing plain cervical radiography. SCIWORA was defined as spinal cord injury demonstrated by magnetic resonance imaging, when a complete, technically adequate plain radiographic series revealed no injury. RESULTS: Of the 34,069 patients entered, there were 818 (2.4%) with cervical spine injury, including 27 (0.08%) patients with SCIWORA. Over 3,000 children were enrolled, including 30 with cervical spine injury, but none had SCIWORA. The most common magnetic resonance imaging findings among SCIWORA patients were central disc herniation, spinal stenosis, and cord edema or contusion. Central cord syndrome was described in 10 cases. CONCLUSION: In the large NEXUS cohort, SCIWORA was an uncommon disorder, and occurred only in adults.

Adult↗
PubMedDate not supplied

Light equalization radiography.

An electro-optical, photographic dodging technique, called light equalization radiography (LER), has been developed. The use of LER extends the dynamic range of radiographic film by enhancing the film contrast in the "toe" region of a radiographic film. Contrast recorded above some predetermined optical density is unaffected. The use of LER permits high-contrast films to be used in radiographic exams where low-contrast, "latitude" film types have been used traditionally, e.g., in chest radiography.

Humans↗
PubMed1979

Digital radiography using a computed tomographic instrument.

A prototype computed radiography (CR) system was evaluated for its efficacy as an independent diagnostic modality. Preliminary measurements of high contrast resolution, low contrast perceptibility, and dose were obtained. Clinical examinations including skull, abdomen, liver, gallbladder, biliary system, spine, and extremities were performed as an adjunct to either computed tomography or CR. The data suggest that CR can be an effective diagnostic imaging modality by itself. Advantages over conventional radiography include high scatter rejection, low patient dose, wide dynamic range, and good low contrast sensitivity for large objects; disadvantages, its long exposure time and relatively poor high contrast spatial resolution.

Biliary Tract↗
PubMed1987

Dental radiography: efficacy in the assessment of intraosseous lesions of the face and jaws in asymptomatic patients.

In this investigation the efficacy of dental radiography for the detection of occult intraosseous lesions of the face and jaws was evaluated. An analysis of 30 million health insurance records indicated that the period prevalence of malignant lesions was less than 5 cases/million/year, and for benign lesions approximately 100 cases/million/year. Data from a controlled observer-performance study showed that radiographic sensitivities ranged between 50% and 80%. The cost per true-positive finding was estimated to be +8.6 million per malignant case and +430,000 per benign case. An assessment of the dosimetric literature indicated that the benefits of radiographic screening as a means for early detection of a malignancy appear to be counterbalanced by the risk of causing a radiation-induced malignancy. Taken together, these data demonstrate that dental radiography is not efficacious for the purpose of detecting occult lesions.

Costs and Cost Analysis↗
PubMed1993

Radiovisiographic diagnosis of dental caries: initial comparison of basic mode videoprints with bitewing radiography.

Radiovisiography (RVG) is a commercially available, dental radiographic digital imaging system which is claimed to rival conventional techniques in terms of decreased radiation dose and the production of instantaneous images. The aim of this study was to compare in vitro the sensitivities and specificities derived from three examiners using conventional bitewing radiographic film (D and E speed) with those achieved by the same examiners using basic mode RVG bitewing videoprints of occlusal and approximal caries. Videoprints were used in this study, as they are the principal method of archiving radiovisiographic images, unless a separate compatible personal computer is used. The histological appearance of the subsequently sectioned teeth was used as the validating criterion. The in vitro results of basic mode RVG suggest that for occlusal caries, overall the sensitivity and specificity of RVG videoprints are similar to those of bitewing radiography. For approximal caries, the specificity of RVG videoprints was similar to that of bitewing radiography, but the sensitivity was slightly lower. Further work using the different modes available and electronically modified images is indicated.

Dental Caries↗
PubMed2004

Bitewing and digital bitewing radiography for detection of caries lesions.

When radiography is applied in the clinic for caries detection, the recommended technique is bitewing projection (Gröndahl, 1994). This technique was introduced by Raper (1925) and has continued with only minor alterations. The aims of this report are to provide evidence for (1) optimal bitewing recording for individual examinations and clinical trials, (2) advantages and disadvantages of digital receptors for bitewing examinations, (3) the diagnostic outcomes and limitations of bitewing radiography, and (4) computer-automated detection of caries.

Clinical Trials as Topic↗
PubMed1989

Marginal bone in periodontal disease: an evaluation of image quality in panoramic and intra-oral radiography.

Five observers assessed the panoramic and full-mouth (14 periapical and four posterior bitewing) radiographs of 20 patients each for the ability to interpret and measure the marginal bone level. The image quality of each site was classified as excellent, acceptable or unacceptable. Depiction errors affecting interpretability and measurability were also noted. In the upper arch, the frequency of uninterpretable and non-measurable sites was almost equal for panoramic and periapical radiography. Image quality was better with periapical radiography in the lower arch. In the posterior regions of both arches, more sites could not be measured from panoramic compared with bitewing radiographs. Due to overlapping the distal surface of the maxillary canine and the mesial surface of the first maxillary premolar could often not be interpreted in either panoramic or periapical radiographs, but infrequently in the bitewings. In the lower arch, the most frequent depiction error was inadequate density in the incisor region of panoramic radiographs. On the basis of these results, we proposed that in clinical practice the panoramic radiograph can be supplemented with individually selected periapicals. In epidemiological studies, the panoramic radiograph should be combined with a premolar bitewing radiograph.

Adult↗
PubMed2000

Evaluation of bone height and bone density by computed tomography and panoramic radiography for implant recipient sites.

The objective was to compare the bone height and bone density measurements of implant recipient sites by panoramic radiography and computed tomography. Thirty-seven sites of 21 patients were evaluated using both panoramic radiography and computed tomography. The bone height was measured as the vertical distance from the alveolar crest to the closest anatomical landmark. Density was compared by means of densitometric measurements. Data was evaluated using paired t-test and Pearson's correlation coefficient analysis. Although bone heights measured with the two imaging modalities differed significantly (p < 0.05), there was a significant correlation between bone density measurements (r = 0.93, p = 0.0). Measurements of bone height as well as bone density was found to be comparable using either radiographic method.

Alveolar Bone Loss↗
PubMed1977

Phantom measurements of absorbed doses in dental radiography.

Some phantom measurements of absorbed doses from Norwegian dental radiography are presented. The mean bone-marrow dose from a single molar bite-wing projection was assessed to 1 mrad, a conventional full mouth examination (10 exposures) 7 mrad and an orthopantomographic exposure 2 mrad. The population dose from Norwegian dental radiography was estimated to be: mean bone-marrow dose 1 mrad and genetically significant dose 0.012 mrad.

Bone Marrow↗
PubMed2004

Digital radiography: update for oral health care workers.

Digital Radiography is an imaging system that does away with the use of films. It constitutes an advance in computer technology and has made a significant impact on the field of Maxillofacial- and Dental Radiology. This paper presents an overview of the basic concepts and applications of dental digital radiography and compares it with conventional film-based imaging. In addition, it provides a thorough understanding of the direct, semi-direct and indirect dental digital imaging systems with their advantages and disadvantages. Universal acceptance of digital radiographic imaging as a diagnostic tool makes it important for oral health care workers to understand the principles thereof and to master the techniques involved in acquiring a diagnosable digital radiographic image.

Humans↗