Photostimulable Phosphor Research Articles

Assessment and quantification of photostimulable phosphor plate artifacts

<h3>Background</h3> Photostimulable phosphor (PSP) plate artifacts can result in radiopaque areas superimposed over radiologic images, which can affect interpretation. There is currently no objective metric for artifact severity, which could help determine the impact on diagnostic interpretation. <h3>Objectives</h3> To develop a method to objectively quantify artifact severity on PSP plates. <h3>Study Design</h3> Artifacts were identified on clinically used and damaged PSP plates, and assessed using three parameters: surface area, intensity, and location. A grid system was used to quantify the surface area. For intensity, histogram analyses resulted in the development of pixel value thresholds. Location was binarized as grids within and outside a "critical zone." The critical zone is operationalized as an area within which carious lesions are more frequently identified. To define this area, unrestored interproximal carious lesions identified on 190 complementary metal oxide semiconductor (CMOS) images, acting as the artifact-free gold standard, were traced to create a heatmap. Together, these three metrics allowed for the development of an artifact scoring system. <h3>Results</h3> The image critical zone occupied 32.3% of the total sensor area. Two different peaks were identified on the plate histograms, which visually correlated with two distinct types of artifacts. Bending and phosphor degradation resulted in increased numbers of grids that were within a lower pixel value range (40 to 100). In comparison, scratches and surface peeling resulted in increased numbers of grids within a higher pixel value range (above 100). <h3>Conclusion</h3> An image "critical zone" was defined where carious lesions are imaged more frequently. Intensity and surface area have been combined to quantify artifact severity. These metrics allowed for the development of an artifact scoring system, which can then be used to assess the impact on image interpretation. This research lays the groundwork for the future development of a quality control protocol for PSP plates. <b>Statement of Ethical Review</b> Human/Animal subjects were used and this study was approved by an institutional ethics panel.

Analysis of image defects in digital intraoral radiography based on photostimulable phosphor plates.

In digital intraoral radiography (DIR), images with defects caused by the digital process are sometimes produced. Hence, we analyzed DIR images with defects taken using the photostimulable phosphor (PSP) plate method and then classified these images based on the causes of the defect. The aim of this study was to classify defects in DIR using the PSP plate system, and to discuss the causes of each type of defect and the methods that can prevent their occurrence. Images with defects due to the two PSP plate systems (Arcana and Arcana Mira) were selected and classified according to the defect. Image defects caused by geometrical techniques that occur in both the film and PSP plate methods were excluded from this study. Moreover, changes in the rate of occurrence of images with defects over time were analyzed in this study. The defects in images obtained by the PSP plate system were classified into six types, which were further divided into those caused by machine error or human error. Both types of error could influence the diagnostic performance. Machine error accidentally and rarely occurred; thus, the prevention of such errors is difficult. However, human error, especially errors caused by photo-induced discharge, could be prevented using appropriate measures. In DIR systems using the PSP plate method, human error should be prevented by education and training to improve operation.

Evaluation of resolution characteristics of digital intraoral radiographic images using a task transfer function.

This study aimed to quantitatively examine the effect of digital image processing of digital intraoral radiographic images on the resolution characteristics of the output image using a task transfer function (TTF). A photostimulable phosphor system with three types of image processing filters, including periodontal, endodontic, and dentine-to-enamel junction filters, was used. Each filter can be used in conjunction with the sharpness filter (+ S). Images were obtained from the original phantom, which combined aluminum disk and plate. The TTF, which indicates the resolution characteristics, was calculated. A one-dimensional profile curve was also measured, and the fluctuation in the pixel value was evaluated in detail. The results were compared to investigate the effects of digital image processing on digital intraoral radiographic images. The TTF values were specific to each filter. The change in the TTF strongly reflected the characteristics of the one-dimensional profile curve. The TTF was compared with a one-dimensional profile curve and was able to quantitatively express the resolution characteristics of all directions in the image. We attempted to evaluate the resolution characteristics of digital intraoral radiographic images with image processing filters using the TTF. The effect of each image processing filter and the + S filter on the resolution can be simply expressed using the TTF. Our results show that the TTF is useful for characterizing the resolution characteristics of image processing filters for image quality.

Clinical extension of proximal carious lesions compared to bitewing radiographs using photostimulable phosphor plates (PSP)

ObjectivesThe aim of this study was to evaluate the use of digital bitewing radiographs using photostimulable phosphor (PSP) plates in the estimation of the true extension of proximal carious lesions. MethodsThe sample size was calculated to be 70 teeth. Adult patients with a minimum of one posterior tooth with primary proximal caries lesions were included. A preoperative bitewing radiograph was taken and the extension of the carious lesion was measured from the most prominent point on the adjacent sound tooth to the deepest axial point of the lesion. An experienced general dentist provided the restorative treatment and made a polyvinyl siloxane impression of the cavity preparation. Clinical caries extension was measured from the most prominent point of the adjacent tooth until the deepest boundary of the axial wall of the preparation on the impression. Postoperative radiographs were taken at the completion of restorative care. The bitewing radiographs were done using PSP plates and caries extension measurements were performed using measuring tools of the digital radiography software. Pairwise comparisons were made between preoperative and postoperative radiographs, and the true clinical depth measurements using paired t-tests. ResultsIn total, 73 teeth from 44 subjects were included. A significant difference of 0.82 mm was found between preoperative radiographs and clinical measurements (p<0.001). Similarly, comparisons between preoperative and postoperative radiographic measurements showed significant differences of 0.99 mm (p<0.001). ConclusionsThe study found that the true clinical extension of proximal caries after non-selective caries removal was significantly deeper than the preoperative radiographic extension assessment. This was not influenced by the tooth type, the location of the tooth, or the affected tooth surfaces. Clinical SignificanceWhen a non-selective caries removal strategy is adopted, clinicians should be aware that PSP bitewing radiographs underestimate the true clinical extension of proximal caries lesions. This will have an impact on clinicians’ practice and restorative treatment decisions.

Does enhancement filter application increase the diagnostic accuracy of misfit detection at the implant-prosthesis interface?

Statement of problemMisfits at the implant-prosthesis interface may increase complications in dental implants and affect peri-implant tissue health. Periapical radiographs are the most used imaging examinations for detecting misfits at the implant-prosthesis interface, although digital systems have largely replaced film-based radiographs. Whether postprocessing tools such as enhancement filters assist diagnosis by highlighting misfits is unclear. PurposeThe purpose of this in vitro study was to assess the influence of enhancement filter application in the diagnostic accuracy of misfit detection at the implant-prosthesis interface. Material and methodsA total of 32 dental implants were placed in dry human mandibles. A polyester strip was inserted at the implant-prosthesis interface to simulate a 50-μm misfit; prosthetic crowns installed directly on the implant platforms were used as controls. Standard paralleling periapical images were acquired by using a semidirect system (photostimulable phosphor plate) with the application of Highlight, Invert, and Colorization filters, as well as a direct system (metal oxide complementary semiconductor sensor) with filters Sharpness 3, Invert, and Pseudocolorization. Oral radiologists evaluated the images with and without the application of filters. The areas under the receiver operating characteristics curves (Az values), sensitivity, specificity, accuracy, positive predictive value, and negative predictive values were calculated. The Az values were compared with the receiver operating characteristic (ROC) curves comparison test of the Epidat 3.1 software (α=.05). ResultsAlthough images without filter application presented descriptively higher diagnostic values than those with filter application, the Az values for images with and without filter application in both semidirect and direct systems showed no significant differences (P>.05). ConclusionsEnhancement filter application did not significantly influence the diagnostic accuracy of misfit detection at the implant-prosthesis interface.

How is the Use of Digital Dental Radiology in a Developing Country? An Overview of Brazil

The aim of this study was to assess the use of digital dental radiology in Brazil, by focusing on the use of image receptors, imaging exams and digital image enhancement tools, also assessing the methods of professional image transfer. Questionnaires were distributed in person on dental meetings and digitally via messaging (WhatsApp®) and mailings list. The sample of this cross-sectional study consisted of 478 questionnaires. Most participants were woman (n=315, 65.9%), with average age of 33.8±9.2 years. Descriptive and frequency analysis was performed. Chi-square and Fisher’s exact tests were used (α=0.05). Most dentists worked at shared dental clinics (34.7%) and use digital image receptors (51.1%), but a representative percentage (48.9%) still exclusively use radiographic films. Photostimulable phosphor plate is the most used digital image receptor. Among extraoral exams, panoramic radiography (PAN) is the most used. Regarding dental specialties, oral radiologists and oral and maxillofacial surgeons mostly use cone-beam computed tomography (p&lt;0.001). Most dentists who use digital systems make use of digital image enhancement tools (87.8%), mainly contrast, zoom, brightness and measurements. The most common method of professional image transfer (professional-professional and professional-patiens) is by email, with few dentists using online app and social media (26%). Therefore, while most Brazilian dentists use digital imaging systems, a significant percentage still exclusively use radiographic films. The most extraoral imaging exams used is PAN. Regarding image enhancement tools, brightness and contrast adjustments, zoom and measurements are the most applied. Finally, dentists generally use email for professional image transfer.&#x0D;

Comparison of Diagnostic Ability of Conventional Film and Storage Phosphor Plate in Detecting Proximal Caries with Direct Measurements by Stereomicroscope: A Diagnostic Test Evaluation.

Background:Radiography plays an important role in detection of interproximal caries. The aim of study is to compare diagnostic ability of conventional film and photostimulable phosphor (PSP) with direct measurement using stereomicroscope in detecting proximal caries.Methodology:In this descriptive study – diagnostic test evaluation, 200 proximal surfaces of 100 extracted human posterior teeth were radiographed with dental X-ray unit. Evaluation of conventional and digital radiographs was performed twice by three observers. Carious lesions were classified based on a four-point scale (R0–R3) suggested by Abesi et al. Weighted kappa coefficients were calculated to assess intra- and interobserver agreement for each image set. Indices of diagnostic ability calculation were based on the first readings of the three observers. The scores were compared with the histological gold standard using receiver operating characteristic (ROC) analysis to evaluate diagnostic ability.Results:Intraobserver kappa coefficients calculated for each observer for each method of detecting caries ranged from 0.914 to 0.956. Interobserver kappa coefficients for each image set ranged from 0.8788 to 0.9583. The sensitivity and specificity of film for the first observer were 77.5% and 78.3% and for PSP were 77.5% and 80%, respectively. ROC analysis revealed that there were no statistically significant results (P > 0.05) between Az values for the two detection methods.Conclusion:PSP plate should be preferred over conventional films in detecting cavitated proximal caries. Further studies with more noncavitated proximal surfaces are required to conclusively establish the diagnostic ability of PSP over conventional film.

Hypochlorous acid and white vinegar: Artifact-free COVID-19 disinfection options for photostimulable storage phosphor plates

To examine the artifacts on intraoral photostimulable storage phosphor (PSP) plate images caused by 3 different disinfectants that are effective against pathogens including SARS-CoV-2. Nine new PSP plates, to be wiped with hypochlorous acid (HOCl) in group A, alcohol in group B, and white vinegar in group C, were distributed in 3 groups. Twelve images of each PSP plate with increasing numbers of wipes were examined for artifacts. The comparisons were evaluated by Kruskal-Wallis and post hoc tests. The reliability of the measurements was evaluated using the intraclass correlation coefficient (ICC) and Cohen kappa statistic. Artifacts were observed only on group B images. In terms of artifact scores, the difference between group A and group C was not statistically significant (P > .05), whereas group B artifact scores were significantly higher than group A and group C (P < .05). Intraobserver reliability was perfect (ICC and kappa of 1.0) and interobserver reliability was considered excellent (ICC=0.985) or almost perfect (kappa=0.956). HOCl and white vinegar can be alternative disinfection options for PSP plates tested in this study. Unlike alcohol, they did not produce artifacts. Additional research evaluating their effects on image quality is needed to determine if they are appropriate for disinfection.

Automatic exposure compensation of digital radiographic technologies does not affect alveolar bone-level measurement.

To evaluate whether the automatic exposure compensation in the presence of high-density materials can affect the measurement of alveolar bone level. Thirty regions of seven dry skulls and six mandibles were radiographed with and without a high-density material, using two digital radiographic technologies: photostimulable phosphor plate (PSP, Digora Optime) and sensor (CMOS, Digora Toto), totaling 120 images. The distances from the cement-enamel junction to the alveolar bone crest were measured using cone-beam computed tomography (CBCT) images to represent the reference standard. The same measurements of alveolar bone level and the average of the pixel values of the image were evaluated on the radiographs. Paired t test compared the average pixel values and alveolar bone-level measurements between images with and without high-density material. One-way analysis of variance compared the difference between radiographic and CBCT measurements (α = 0.05). The high-density material reduced the pixel values in PSP (p = 0.002) and CMOS (p < 0.001) technologies, demonstrating the AEC functioning in both technologies. There was no difference in bone-level measurements between the images without and with the high-density material for both technologies (p ≥ 0.091), or between the tomographic and radiographic measurements (p ≥ 0.319). In the presence of high-density material, the automatic exposure compensation reduces the average pixel values of the images (i.e., images get darker), but does not influence the radiographic measurements of alveolar bone level.

Effect of enveloping and disinfection methods on artefact formation on enveloped PSP plate images.

ObjectivesTo investigate the artefacts caused by different disinfection and protection methods that can be used for infection control of photostimulable phosphor (PSP) plates.MethodsThe plates that were enveloped with single or double envelopes were sprayed with an alcohol-containing solution or wiped with an alcohol-containing tissue. Four PSP groups with two plates in each group were formed (A = wiping single envelope, B = wiping double envelopes, C = spraying onto single envelope, and D = spraying onto double envelopes). Any artefacts (1 = no artefact, 2 = presence of artefact less than 0.5 cm wide, and 3 = presence of artefact larger than 0.5 cm wide) on the 12 acquired images were evaluated.ResultsArtefacts (score-3) occurred on the images of Group C-2 PSP plate after the 3rd exposure. According to the Kruskal–Wallis test the difference between the artefact score of the four methods was found significant. Post-hoc comparisons showed the Group C artefact scores were higher than the others and the difference was significant. The total time of enveloping and disinfection processes for groups was; A = 6.30 min, B = 7.58 min, C = 5.48 min, and D = 7.14 min.ConclusionsRegardless of the number of envelopes, wiping with a tissue was less likely to cause artefacts, while spraying was reliable only when double envelopes were used. However, using a tissue and double envelopes, which are less risky in terms of artefact, causes time loss, difficulty in manipulation, environmental pollution and high cost.

Analysis of photostimulable phosphor image plate artifacts and their prevalence.

BACKGROUND Digital radiography has recently been used in dentistry as a substitute for conventional film radiography worldwide. Digital imaging has many advantages and provides new possibilities for recording and interpreting radiographic data. This system uses different types of digital receptors.AIMTo detect the frequency, type, and reasons behind the appearance of intraoral image artifacts acquired by photostimulable phosphor plates (PSP).METHODSThis retrospective descriptive study was conducted in the oral and maxillofacial radiology unit of the dental clinics of the College of Dentistry, Princess Nourah University (PNU). All intraoral digital radiographs were acquired using (Gendex Expert DC., United States) an intraoral X-ray machine with 7 -mA, 65-kVP using a PSP system (Soredex DIGORA Optime imaging plate) and laser scanners (Soredex DIGORA Optime), which can house all sizes of reusable intraoral PSP sensor plates with image acquisition software (MIPACS Dental Enterprise viewer 3.2.2). A total of 50000 intraoral radiographs were retrieved from the clinical database from April 2018 to April 2020 to evaluate the reason, type, and solutions to these image artifacts.RESULTSOverall, 50000 intraoral digital radiographs were acquired in a two-year-period; that is, from April 2018 to April 2020. Of these, 3550 (7.1%) retakes were performed due to the presence of image artifacts. Periapical radiographs were the most common image type of intraoral retakes (80.8%). Imaging artifacts were divided into three categories: operator, plate and scanning errors. Out of 3550 retakes, 5%, 1.37%, and 0.73% were related to operator, plate, and scanning errors, respectively. The cone cut was the most common operator error (988 images), Bite marks were the most common plate error (276 images), and delayed scanning artifacts were the most common scanning errors (145 images). The calculated kappa value for interobserver reliability was 0.99, indicating almost perfect interobserver agreement. CONCLUSIONOur study discussed intraoral image artifacts that were characteristic of PSP, where the most common artifacts were bitemarks, image size reduction, scratches, and delayed scanning.

Clinical comparison of intraoral CMOS and PSP detectors in terms of time efficiency, patient comfort, and subjective image quality.

PurposeThis study compared the effectiveness of complementary metal-oxide semiconductors (CMOS) and photostimulable phosphor (PSP) plates as intraoral imaging systems in terms of time efficacy, patient comfort, and subjective image quality assessment in real clinical settings.Materials and MethodsFifty-eight patients (25 women and 33 men) were included. Patients were referred for a full-mouth radiological examination including 1 bitewing radiograph (left and right) and 8 periapical radiographs for each side (left maxilla/mandible and right maxilla/mandible). For each patient, 1 side of the dental arch was radiographed using a CMOS detector, whereas the other side was radiographed using a PSP detector, ensuring an equal number of left and right arches imaged by each detector. Clinical application time, comfort/pain, and subjective image quality were assessed for each detector. Continuous variables were summarized as mean±standard deviation. Differences between detectors were evaluated using repeated-measures analysis of variance. P<0.05 was accepted as significant.ResultsThe mean total time required for all imaging procedures with the CMOS detector was significantly lower than the mean total time required for imaging procedures with PSP (P<0.05). The overall mean patient comfort scores for the CMOS and PSP detectors were 4.57 and 4.48, respectively, without a statistically significant difference (P>0.05). The performance of both observers in subjectively assessing structures was significantly higher when using CMOS images than when using PSP images for all regions (P<0.05).ConclusionThe CMOS detector was found to be superior to the PSP detector in terms of clinical time efficacy and subjective image quality.

Evaluation of the microstructure, chemical composition, and image quality of different PSP receptors.

This study aimed to assess the microstructure, chemical composition, and image quality of different photostimulable phosphor plates (PSP). Four PSP systems, Express®, Digora®, VistaScan®, and Apixia,® were assessed. Five radiographs of a homogeneous acrylic phantom were obtained with the PSP of each system, to acquire a total of 20 images. The images were objectively evaluated for uniformity using mean grey and standard deviation (SD) of their grey values. PSP receptors were analyzed using scanning electron microscopy (SEM) to determine the thickness of the granule layer and the size of the granules. The chemical composition of the PSP receptors was analyzed using total reflection X-ray fluorescence (TXRF). VistaScan showed more uniform and higher density images than the other tested systems (p < 0.05), as well as the lowest SD of grey values (p < 0.05). Regarding the microstructure of the receptors, Digora and VistaScan had thicker granule layers than Express and Apixia, and VistaScan had smaller granules than Digora and Express (p < 0.05). Fourteen chemical elements were detected in the receptors, with barium being the element with the highest concentration in all PSP systems. The microstructure, chemical composition, and image quality varied among all four PSP receptors studied. VistaScan receptors showed the smallest variation in granule size, one of the thickest granule layers, and the most uniform and least noisy images.

History and Prospects for the Application of X-Ray Diffraction Analysis in Seed Breeding and Seed Study

Introduction. X-ray analysis has been applied for visualizing the internal structure of various objects for over 100 years. However, this method began to be used for assessing the quality of plant seeds only in the early 1980s. The main impediment was a lack of specialized instruments, particularly X-ray sources, that could provide informative images. Advancements in the field of microfocus radiography allowed significant results to be achieved, including the preparation of the National Standard GOST R 596032021 "Agricultural Seeds. Methods of digital radiography".Aim. An analytical review of Russian research studies in the field of X-ray diffraction analysis of plant seeds.Materials and methods. Key stages in the development of microfocus X-ray diffraction analysis of seeds and individual parts of plants for agricultural and other purposes are considered. The design of instruments, including digital ones, created for the implementation of the method are described.Results. In order to obtain informative X-ray diffraction images of plant seeds, which objects are generally characterized by small sizes and small density, the focal spot of the X-ray tube should not exceed several tens of microns under the voltage of not higher than several tens of kilovolts. As a system for visualizing a latent X-ray image, it is preferable to use image receivers based on a screen with a photostimulated phosphor or flat-panel solid-state X-ray detectors. These instruments have been successfully used to identify and describe the radiographic signs of a normal seed and nine main types of defects for 600 plant species.Conclusion. In comparison with the conventional contact radiography, microfocus radiography produces X-ray images of seeds with a projection magnification of the image up to several tens of times. Such images permit highly detailed visualization of the structure of seeds that differ slightly in density.

Revisiting dynamic range and image enhancement ability of contemporary digital radiographic systems.

To assess the dynamic range and enhancement ability of radiographs acquired with contemporary digital systems. Five repeated periapical radiographs of human mandibles with an aluminium step-wedge were acquired using two sensor-based and three photostimulable phosphor plate-based systems and an X-ray unit at ten exposure times 0.020, 0.032, 0.063, 0.080, 0.100, 0.200, 0.320, 0.400, 0.500, and 0.630 s. All images had their brightness and contrast enhanced by two experienced oral and maxillofacial radiologists in consensus and were exported as both the original and enhanced file formats. Mean grey values were obtained from the aluminium steps and tabulated with their corresponding thicknesses for each exposure time, digital radiographic system, and file format. Images with saturated steps were excluded and the mean grey values from the remaining images were averaged to assess image brightness and the angular coefficient of the linear trendlines was generated from the relationship between mean grey values and their corresponding aluminium thicknesses to assess image contrast. Brightness and contrast values were compared using two-way ANOVA with post-hoc Tukey (α = 0.05). Photostimulable phosphor plate-based digital radiographic systems had a broader dynamic range. Longer exposure times produced original images with lower brightness and variable contrast (p < 0.05). Subjective enhancement significantly increased or reduced brightness and/or contrast in some systems (p < 0.05). Contemporary digital radiographic systems present different dynamic ranges and exposure-related brightness and contrast. Image enhancement may be a valuable tool at slightly suboptimal exposure times.

Exploring digital filters for internal root resorption: how can we improve the diagnosis of small lesions?

This study aimed to evaluate the impact of enhancement filters in detecting small simulated internal root resorptions (IRR). Forty-two extracted human teeth were sectioned, connected, and stored in a dry human jaw and X-rayed with photostimulable phosphor plates (PSPs), composing the control group (CG). In the middle-third of the root canals, IRR lesions were simulated using Da Silveira protocol. Later, the specimens were X-rayed to create the test group (TG). All images acquired were exported with seven enhancement filters plus the original image. Three examiners used a five-point Likert scale to evaluate the images regarding the presence/absence of IRR. Diagnostic efficacy was assessed from sensitivity and specificity results. Comparison among filters was performed by using receiver operating characteristic (ROC) curve analysis. Moderate values of Kappa interexaminer (0.403-0.620) and high values of Kappa intraexaminer (0.757-0.915) were observed. The best performance occurred in the CG (p < 0.05). Original images presented the greatest sensitivity and area under the ROC curve (0.595-0.750), while the Endo filter presented the greatest specificity (0.952). Inversion and Pseudo-3D images produced the greatest doubt in the diagnosis, significant for CG with the Pseudo-3D filter (p < 0.05). The Original and 'Endo' filters should be chosen as it offers greater diagnostic ability and allows more confidence during the evaluation.

A cross-sectional survey of dentists' use of digital radiographic techniques in Riyadh, Saudi Arabia

Introduction: Undergraduate oral and maxillofacial radiology curricula are currently undergoing a reform process that is moving toward digital-based radiology that requires dedicated resources to train dental students to the field experience. It is not known if the time is appropriate to totally shift from training students on conventional analog film-based radiology to training them on digital images and the choice of digital system in intraoral and extraoral radiography. Aim: The aim of this study is to assess availability and utilization of the digital radiographic techniques by dental clinics in Riyadh, Saudi Arabia, using a cross-sectional descriptive, epidemiological survey. Materials and Methods: The study included dental departments of nine main governmental hospitals, six dental schools in Riyadh and a representative selected sample of the private dental clinics in Riyadh that included 40 dental clinics. A self-administered e-survey regarding the use of analog or digital radiographic intraoral and extraoral techniques was made. Descriptive statistics are reported in forms of means and range. Results and Discussion: For intraoral radiographic examinations, most clinics (90.9%) used digital systems. Solid-state detectors such as charge-coupled device (CCD) and complementary metal oxide semiconductor sensors were the most popular type digital intraoral sensors (94%) and only 13 locations (26%) used digital photostimulable phosphors plates. For panoramic radiography, almost all (98.1%) used digital systems. Again, the solid-state detectors were the most common digital panoramic system (96.4%). Most respondents had a digital information system to store, retrieve, and display digital radiographs (92.7%), whereas only four locations (5.9%) used hard-copy films or paper prints. Conclusion: Digital imagining is more common than film-based imaging in intraoral radiography in and panoramic radiography in the different dental care delivery sites in Riyadh, Saudi Arabia.

DIAGNOSTIC ACCURACY OF INTRAORAL, EXTRAORAL, AND CBCT-GENERATED BITEWINGS FOR DETECTING APPROXIMAL CARIES AND PERIODONTAL BONE LOSS

<h3>BACKGROUND</h3> With the current coronavirus disease pandemic, dental offices are trying their best to limit intraoral imaging. One solution to overcome this problem is to use extraoral imaging techniques. <h3>OBJECTIVE(S)</h3> The objective of this study was to evaluate the diagnostic accuracy of intraoral bitewings, extraoral bitewings generated by a panoramic machine, and cone beam computed tomography (CBCT)–generated bitewings with 180° and 360° rotations in the detection of dental caries and bone loss. <h3>STUDY DESIGN</h3> The study examined carious defects, alveolar bone levels, and interdental vertical defects in the posterior mandible in 100 interproximal surfaces in a dry human skull. Simulated cavities were created at specific locations and interdental defects were created on both buccal and lingual surfaces where measured amounts of bone were removed to simulate bone loss. Physical measurements of bone removed served as the gold standard. Intraoral bitewings were acquired using photostimulable phosphor sensors with a Kavo LM/CM109 x-ray tube at 70 kVp,7mA and 0.125 seconds. Extraoral bitewings were acquired with a J. Morita panoramic unit at 90 kVp,7mA and 5.5 seconds. CBCT scans were acquired with the J. Morita 3D Accuitomo at 90 kVp and 7 mA setting with a 40 × 40 mm FOV in the Hi-Res-Mode. Four examiners scored the presence and extent of caries and performed alveolar bone measurements. <h3>RESULTS</h3> No statistically significant results were noted with all imaging modalities for the diagnostic efficacy and linear measurement of the defects. Kappa analysis for interoperator reliability was very high. <h3>DISCUSSION/CONCLUSIONS</h3> The diagnostic accuracy of extraoral bitewings generated from panoramic and CBCT machines for detecting dental caries and periodontal bone loss is comparable for all imaging modalities tested. <h3>FUTURE DIRECTIONS</h3> In this study there was no metallic scatter like in clinical situations, so future studies that will incorporate varying degrees of metallic scatter must be done to evaluate the diagnostic efficacy.

Effect of beam quality and readout direction in the edge profile on the modulation transfer function of photostimulable phosphor systems via the edge method.

Purpose: The objective of this study was to investigate the effects of (i) the difference in the beam qualities on the presampled modulation transfer function (MTF) using the edge method and (ii) the readout direction of the edge profile for the photostimulable phosphor (PSP) system. Approach: The International Electrotechnical Commission (IEC) defined a technique using the "radiation qualities based on a phantom made up of an aluminum added filter" (RQA). A general radiographic system with a tube voltage of 50kV and 9.7mm of additional aluminum filtration was used to conform the x-ray to the IEC-specified beam quality definition RQA3. Additionally, we employed two different beams with tube voltages of 60 and 70kV using a dental x-ray unit. The MTF was measured in the readout direction from low-to-high exposure regions and vice versa with respect to the scanning and subscanning directions of the PSP system. Results: The difference in the 50%MTF value for all directions between 60 and 70kV averaged less than . The 50%MTF of RQA3 was on average 0.2 lower than the value for 60kV for each direction. For all beam qualities, no difference was observed between the MTFs measured in the readout direction from the low-to-high exposure regions and vice versa. Conclusions: The MTFs, measured using the dental x-ray unit, were unaffected by the tube voltage, and they were slightly higher than those measured using the RQA3. Furthermore, the MTF was unaffected by the differences in the readout directions of the edge profile.

Proper Management of the Clinical Exposure Index Based on Body Thickness Using Dose Optimization Tools in Digital Chest Radiography: A Phantom Study.

In radiography, the exposure index (EI), as per the International Electrotechnical Commission standard, depends on the incident beam quality and exposure dose to the digital radiography system. Today automatic exposure control (AEC) systems are commonly employed to obtain the optimal image quality. An AEC system can maintain a constant incident exposure dose on the image receptor regardless of the patient thickness. In this study, we investigated the relationship between body thickness, entrance surface dose (ESD), EI, and the exposure indicator (S value) with the aim of using EI as the dose optimization tool in digital chest radiography (posterior–anterior and lateral projection). The exposure condition from the Korean national survey for determining diagnostic reference levels and two digital radiography systems (photostimulable phosphor plate and indirect flat panel detector) were used. As a result, ESD increased as the phantom became thicker with constant exposure indicator, which indicates similar settings to an AEC system, but the EI indicated comparatively constant values without following the tendency of ESD. Therefore, body thickness should be considered under the AEC system for introducing EI as the dose optimization tool in digital chest radiography.