Conventional Film Images Research Articles

Assessment of linear measurements with intra oral grid on intra oral periapical image – A comparison of digital and conventional film images using bisecting angle and paralleling techniques

Background: The success of various treatments protocols depends on pre-operative diagnostic aids such as radiographic assessment with linear measurements, in such scenario radiographic grid with its unique design aids like a scale for image analysis on intraoral periapical radiograph. Hence, the intra oral grid is a simple and accurate way of measuring objects, and another advantage is to overcome various magnification errors associated with measurements. So, the present study was designed to know its accuracy in assessing the linear measurements. Materials and Method: The study sample comprised a total of 40 subjects, which were categorized into four groups. A total of 240 exposures were taken, where each patient was subjected to six radiographs, of which two are conventional intraoral periapical radiographs without grid, and two are conventional intraoral periapical radiographs with grid by bisecting and paralleling technique and another two radiographs are taken by digital CMOS sensor with intraoral periapical grid in all four groups. The measurements were performed on the radiographs using scale and divider and in case of radiograph with the grid by counting the grid lines from specific points. Results: The results of the study revealed on comparison of conventional and digital radiographs with and without a grid in both bisecting and paralleling technique in all the four groups, there was a statistically significant difference noticed with digital radiography compared to the conventional method in assessing the measurements with the grid with P value

Author's reply:In vitrocomparison of digital and conventional bitewing radiographs

We thank Drs Aps, Berkhout and Goren for their interest in our recently published paper.1 To briefly summarise our in vitro results, we found that the diagnostic quality of conventional film and digital images, which were exposed and viewed by a new wireless handheld unit, was comparable. This handheld unit has become especially advantageous in paediatric dentistry and has potential for use in nursing homes, humanitarian missions, forensic dentistry and with disabled patients. Firstly, we want to emphasise that no consultants were involved in this study, and none of the authors received any fee paid directly or from any other financial agreement. Secondly, there is no doubt that nothing is more important than the safety of the operators and patients when using these kinds of devices. Thirdly, this study was not a technical report! It is well known that the detection of approximal caries of primary teeth is difficult with the naked eye.2 The proximal surfaces of teeth which can not be visually inspected must be evaluated by radiography.3 Traditionally, bitewing radiographs have been employed in addition to clinical examination of approximal surfaces.4,5 On the other hand, using radiographs in paediatric patients should be considered carefully. In paediatric patients, X-ray exposure should be reduced.6 Nevertheless, it has been advocated that 5-year-old children should be exposed to bitewing radiography for examination of approximal surfaces.7,8 By using these portable digital X-ray machines, children can be diagnosed radiographically and clinically in their dental units. Also, these portable digital X-ray machines can be used while children are treated under general anaesthesia or sedation. The system that we used in our study combines an X-ray source, digital radiography sensor and computer processing in one completely portable and wireless hand-held unit. In the conclusions section of the study, the recommendation that “further investigations should be performed, in order to determine safety and backscatter radiation dose of the handheld unit” could be added, as the reviewers stated. But, we do not have the same opinion as the reviewer that holding the device can never assure a safe distance behind the X-ray machine. We believe that parallel to technological progression, the digital X-ray machines will become smaller, portable and provide a very low radiation exposure to patient and operator. Moreover, it has been shown in a technical report,9 that the handheld battery-operated portable X-ray system presented no risk to the patient or to the operator, and measured doses were well below recommended levels. In the Material and methods section of the study, reviewers affirmed that no soft tissue equivalent material was used in the setup of the study. We placed 14 mm dental wax in front of the teeth to simulate soft tissue, as Haak et al stated,10 and this was mentioned in the Materials and methods section of the study. We thank again Drs Aps, Berkhout and Goren for their comments and we respect their critisms, especially the recommendation that the safety of the handheld device is more important than image quality for operator and patient.

Relationship between radiation dose reduction and image quality change in photostimulable phosphor luminescence X-ray imaging systems

The aim of the study was to clarify the change in image quality upon X-ray dose reduction and to re-analyse the possibility of X-ray dose reduction in photostimulable phosphor luminescence (PSPL) X-ray imaging systems. In addition, the study attempted to verify the usefulness of multiobjective frequency processing (MFP) and flexible noise control (FNC) for X-ray dose reduction. Three PSPL X-ray imaging systems were used in this study. Modulation transfer function (MTF), noise equivalent number of quanta (NEQ) and detective quantum efficiency (DQE) were evaluated to compare the basic physical performance of each system. Subjective visual evaluation of diagnostic ability for normal anatomical structures was performed. The NEQ, DQE and diagnostic ability were evaluated at base X-ray dose, and 1/3, 1/10 and 1/20 of the base X-ray dose. The MTF of the systems did not differ significantly. The NEQ and DQE did not necessarily depend on the pixel size of the system. The images from all three systems had a higher diagnostic utility compared with conventional film images at the base and 1/3 X-ray doses. The subjective image quality was better at the base X-ray dose than at 1/3 of the base dose in all systems. The MFP and FNC-processed images had a higher diagnostic utility than the images without MFP and FNC. The use of PSPL imaging systems may allow a reduction in the X-ray dose to one-third of that required for conventional film. It is suggested that MFP and FNC are useful for radiation dose reduction.

In vitrocomparison of digital and conventional bitewing radiographs for the detection of approximal caries in primary teeth exposed and viewed by a new wireless handheld unit

The aim of this study was to compare the diagnostic quality of a new wireless handheld unit (ADX4000; Dexcowin Co. Ltd, Korea) on conventional bitewings and its LCD screen for the detection of approximal caries in primary teeth. In total, 108 approximal surfaces of primary teeth were examined in vitro by 3 observers. Conventional films were viewed under subdued lighting conditions on a conventional view box. Digital 3.5 inch images were displayed on the built-in monitor of the ADX4000 and digital 17 inch images were viewed on a 17 inch monitor. The true caries diagnosis was based on histological assessment of the approximal surfaces after sectioning the primary teeth. Receiver operating characteristic (ROC) curve (A(z)) analysis was used to assess the diagnostic quality of imaging modalities. The areas under the ROC curves ranged from 0.786 (digital 17 inch) to 0.813 (digital 3.5 inch). No statistically significant differences were found between the three modalities for detecting approximal caries. It was concluded that the diagnostic quality of conventional film and digital images, which were exposed and viewed by a new wireless handheld unit, was comparable.

Comparison of two imaging modalities: F-speed film and digital images for detection of osseous defects in patients with interdental vertical bone defects

The aim of the present study was to compare the diagnostic accuracy of F-speed conventional film, unenhanced digital images and inversion-enhanced digital images for the detection of osseous defects in patients with vertical bone defects. 23 vertical osseous defects in the mandible were evaluated. Intrasurgical measurements were made from the cementoenamel junction (CEJ) to the deepest extension of the osseous defects by one of the researchers. Radiographic measurements were obtained on conventional F-speed film, unenhanced digital images and inversion-enhanced digital images by six examiners. From each measure the corresponding probe measure was subtracted to form a difference score. Significant differences in means of difference scores were found among examiners within each imaging modality, and among the modalities within five of the six examiners. A significant (P<0.001) interaction term for the ANOVA indicated that differences among modality means were not the same across all examiners. The difference means were significantly different from zero for five of the six examiners with conventional F-speed film, four of six with inversion enhanced digital images, but for only one of six for unenhanced digital images. The reliability coefficient computed on a per examiner basis was 0.90 for conventional F-speed film, 0.94 for unenhanced digital image and 0.79 for inversion-enhanced digital image. In this study, unenhanced digital imaging was found to be superior to conventional F-speed film and inversion-enhanced digital images for accurately imaging periodontal osseous defects in patients.

In vitrocomparison of conventional film and direct digital imaging in the detection of approximal caries

To compare the diagnostic accuracy of conventional film, unenhanced direct digital and inversion grayscale direct digital imaging in the detection of approximal caries. 150 approximal surfaces of extracted permanent molars and premolars were selected for the study on the basis of varying lesion depth. The teeth were radiographed using Ektaspeed Plus film; digital images were made with a Schick CMOS-APS sensor. 7 examiners evaluated 58 randomized images of each modality. Histological sectioning of the teeth was used to verify the presence and extent of decay. No significant difference was found between the diagnostic accuracies of the three imaging modalities (P=0.226). Analysis of the diagnostic accuracy of the three modalities on lesion depth showed no statistically significant interaction; however, the main effect of the lesion depth was significant (P<0.001, eta(2)=0.936). The overall diagnostic accuracy of the three modalities in the detection of approximal carious lesions was comparable. All three modalities performed poorly in the detection of enamel lesions.

Imaging of root canal fillings: a comparison of subjective image quality between limited cone‐beam CT, storage phosphor and film radiography

To compare the subjective quality of limited cone-beam computed tomography (LCBCT), storage phosphor plate (SPP) and F-speed film images for the evaluation of length and homogeneity of root fillings. Root canals of 17 extracted permanent mandibular incisor teeth were filled. With the teeth placed in their jaws, images were obtained with Accu-I-Tomo LCBCT, Digora Optime image plate system and F-speed film using exposure parameters yielding 'clinically' acceptable density and contrast. Three radiologists and three endodontists independently rated the quality of all images in respect to homogeneity and the length of root fillings using a 3-graded scale. Evaluations were undertaken in two sessions. In the first, the coronal LCBCT images were not included. In the second, both coronal and sagittal LCBCT images were rated along with F-speed film and SPP images. were compared using the Friedman test (P < 0.05). Pair-wise comparisons of systems were completed using the Wilxocon signed-ranks test (P < 0.05). Kappa was used to measure interobserver agreement. Results Digora images were rated superior, consecutively followed by F-speed films and LCBCT images, for the evaluation of both homogeneity and length of root fillings in both the evaluation sessions (P < 0.05). Kappa ranged from slight to moderate for the length evaluation of root fillings and from poor to fair for the evaluation of homogeneity of root fillings. Image quality of storage phosphor images was subjectively as good as conventional film images and superior to LCBCT images for the evaluation of both homogeneity and length of root fillings in single-rooted teeth.

An ex vivo comparison of conventional and digital radiography for perceived image quality of root fillings

To compare the subjective image clarity of two different speed films and the Digora phosphor plate images with respect to the length and homogeneity of root canal fillings. Root canal treatment was performed on 20 extracted permanent mandibular first molar teeth. Standardized images of each tooth positioned in a dried mandible were obtained with E- and F-speed films and Digora storage phosphor plates (SPP) at 0 degrees and 30 degrees horizontal angulations using the optimal exposure time recommended for each system. Five endodontists and five radiologists rated the image clarity of E- and F-speed radiographs as well as the original and enhanced Digora images. The data were compared using the Wilcoxon signed rank test (P < 0.01). Inter-observer agreement was determined by Cohen's kappa. Enhanced digital images were rated as superior followed by E- and F-speed films and then the original digital images for the evaluation of both homogeneity and length (P < 0.01) of root canal fillings. Agreement among endodontists and radiologists measurements was high in all of the imaging methods (kappa = 0.87). Perceived image quality of the enhanced Digora images was superior to the original Digora and conventional film images for the evaluation of root fillings. However, E-speed film provided a significantly better image clarity in comparison with F-speed and original Digora images.

1140 poster The electronic portal imaging device (EPID) versus the conventional port film imaging system: the aspect of resorcues involved in the radiation technologist

1140 poster The electronic portal imaging device (EPID) versus the conventional port film imaging system: the aspect of resorcues involved in the radiation technologist

Digital photography: a primer for pathologists.

The computer and the digital camera provide a unique means for improving hematology education, research, and patient service. High quality photographic images of gross specimens can be rapidly and conveniently acquired with a high-resolution digital camera, and specialized digital cameras have been developed for photomicroscopy. Digital cameras utilize charge-coupled devices (CCD) or Complementary Metal Oxide Semiconductor (CMOS) image sensors to measure light energy and additional circuitry to convert the measured information into a digital signal. Since digital cameras do not utilize photographic film, images are immediately available for incorporation into web sites or digital publications, printing, transfer to other individuals by email, or other applications. Several excellent digital still cameras are now available for less than 2,500 dollars that capture high quality images comprised of more than 6 megapixels. These images are essentially indistinguishable from conventional film images when viewed on a quality color monitor or printed on a quality color or black and white printer at sizes up to 11x14 inches. Several recent dedicated digital photomicroscopy cameras provide an ultrahigh quality image output of more than 12 megapixels and have low noise circuit designs permitting the direct capture of darkfield and fluorescence images. There are many applications of digital images of pathologic specimens. Since pathology is a visual science, the inclusion of quality digital images into lectures, teaching handouts, and electronic documents is essential. A few institutions have gone beyond the basic application of digital images to developing large electronic hematology atlases, animated, audio-enhanced learning experiences, multidisciplinary Internet conferences, and other innovative applications. Digital images of single microscopic fields (single frame images) are the most widely utilized in hematology education at this time, but single images of many adjacent microscopic fields can be stitched together to prepare "zoomable" panoramas that encompass a large part of a microscope slide and closely simulate observation through a real microscope. With further advances in computer speed and Internet streaming technology, the virtual microscope could easily replace the real microscope in pathology education. Later in this decade, interactive immersive computer experiences may completely revolutionize hematology education and make the conventional lecture and laboratory format obsolete. Patient care is enhanced by the transmission of digital images to other individuals for consultation and education, and by the inclusion of these images in patient care documents. In research laboratories, digital cameras are widely used to document experimental results and to obtain experimental data.

Conventional, Digital and Contrast–Enhanced Bitewing Radiographs in the Decision to Restore Approximal Carious Lesions

The purpose of the present investigation was to compare the accuracy of treatment decisions in proximal sites using three intra–oral radiographic systems. Additionally, the impact of an automated non–linear grey–level display was evaluated. Ten observers assessed 84 surfaces on bitewing radiographs for their requirement of restorative treatment using a 6–rank confidence scale. Radiographs were taken with conventional film images (Ultraspeed), a storage phosphor plate (Digora) and a CCD system (Dexis). Additionally, the Dexis software was expanded by a contrast enhancement routine (Dexis+). The restorative treatment threshold was defined as presence of macroscopic cavitation. Regarding the areas below mean ROC curves no significant differences were detected between the groups (p>0.05). Likelihood ratios for positive test results were: 5.29 (Ultraspeed), 8.14 (Digora), 9.67 (Dexis) and 11.37 (Dexis+). The accuracy of restorative treatment decisions based on digital and conventional radiographs is comparable. If a dichotomous treatment decision was requested, the digital systems demonstrated a notable tendency towards higher likelihood of true–positive decisions.

Impact of PACS on the Education of Radiology Residents: The Residents' Perspective

Rationale and Objectives Because digital imaging and the picture archiving and communication system (PACS) are replacing radiographic film, the effect of PACS on residents' perceptions and their educational experience was investigated. Materials and Methods Residents taking part in large diagnostic radiology training programs at two hospitals were surveyed. Approximately 75% of radiographic studies were reviewed with the use of PACS at both hospitals. Survey topics included technical and didactic issues based on direct and indirect comparison with analog (conventional film) images. Results Fifty residents were polled (20 respondents). The majority has been using PACS for more than 1 year (14 of 20, 70%) to interpret 75%–100% of cases (11 of 20, 55%). The majority believed that PACS improved patient care (15 of 20, 75%) and their educational experience (15 of 20, 75%). A minority believed that increased patient throughput was harmful to the educational experience (five of 20, 25%) because it permitted attending radiologists to review cases too quickly (four of 20, 20%). Residents favored PACS over hard-copy images for ease of manipulation, resolution, and ability to see pathologic conditions and normal anatomic characteristics. Conclusion Residents believe that PACS has positively affected their learning experience and does not negatively affect the quality of resident education.

Data analysis for detection and localization of multiple abnormalities with application to mammography

In assessing diagnostic accuracy it is often essential to determine the reader's ability both to detect and to correctly locate multiple abnormalities per patient. The authors developed a new approach for the detection and localization of multiple abnormalities and compared it with other approaches. The new approach involves partitioning the image into multiple regions of interest (ROIs). The reader assigns a confidence score to each ROI. Statistical methods for clustered data are used to assess and compare reader accuracy. The authors applied this new method to a reader-performance study of conventional film images and digitized images used to detect and locate malignant breast cancer lesions. The ROI-based approach, the free-response receiver operating characteristic (FROC) curve, and the patient-based approach handle the estimation of the false-positive rate (FPR) quite differently. These differences affect the measures of the respective areas under the curves. In the ROI-based approach the denominator is the number of ROIs without a malignant lesion. In the FROC approach the average number of false-positive findings per patient is plotted on the x axis of the curve. In contrast, the patient-based approach mishandles the FPR by ignoring multiple detection and/or localization errors in the same patient. The FROC approach does not lend itself easily to statistical evaluations. The ROI-based approach appropriately captures both the detection and localization tasks. The interpretation of the ROI-based accuracy measures is simple and clinically relevant. There are statistical methods for estimating and comparing ROI-based estimates of accuracy.

High-Resolution Paleoclimatic Information from Chinese Eolian Sediments Based on Grayscale Intensity Profiles

Grayscale intensity profiles from photographic images offer a rapid means of obtaining paleoclimate proxy records from Chinese loess, dune sand, and paleosols. Although the data can be obtained using conventional 35-mm film images, a digital camera and laptop computer will produce a high-resolution grayscale profile at a field site within minutes. Comparison of grayscale profiles with profiles of magnetic susceptibility measured down loess and dune-sand sections at sites on the Loess Plateau and Tibetan Plateau in a range of altitudes and climatic regimes shows that the two parameters are highly correlated. Therefore, grayscale intensity is a convenient alternative to magnetic susceptibility for generating paleoclimatic data in the loess and desert-margin regions of China. The resolution of both grayscale and susceptibility profiles ultimately is limited by bioturbation, which is most pronounced in paleosols.

Economic expediency of digital photoroentgenography

In the absence of centralized supply and allocation of X-ray equipment and under conditions of funding cuts the problem of economic expediency of purchase of given X-ray diagnostic is of paramount importance [1]. The goal of this work was to discuss advantages of digital photoroentgenography over conventional X-ray film technology. The practical purpose of this work is to provide information required for adequate choice of a photoroentgenographic device. To determine the cost of a photoroentgenographic picture consider the structure of the photoroentgenographic room designed to obtain conventional X-ray film or digital images (Figs. 1-3). The elements of the diagrams are explained in Table 1.

A picture archiving and communications system featuring multiple monitors using Windows98.

We present an effective approach to manage, review, and distribute Digital Imaging and Communications in Medicine (DICOM) images with multiple monitors using Windows98 (Microsoft Corp, Redmond, WA) that can be implemented in an office-based setting. Computed tomography (CT), magnetic resonance imaging (MRI), and angiographic DICOM images were collected, compressed, and stored using Medweb (Medweb, Inc, San Francisco, CA) software. The Medweb server used the Linux/UNIX operating system on a Pentium 333-MHz processor with 128 MB of RAM. Short-term storage capacity was about 2 weeks with routine usage of an 11-GB hard drive. Images were presented for reading on a dual-monitor Windows98 Pentium display station with 160 MB of RAM using a Medweb/Netscape (Netscape Communications Corp, Mountain View, CA) viewer. There was no significant discrepancy in diagnosis between electronic and conventional film images. Mean reading time for 32 cases was 118 seconds. The Medweb JAVA plug-in viewer loaded the first image within 30 seconds of selecting the case for review. Full uncompressed 16-bit images allowed different window settings to better assess for pathology. Multiple monitors allowed viewing various hanging protocols. Cine viewing was also possible. Key diagnostic images were electronically transmitted to referring physicians. On-call radiologists were able to access images through the Internet. By combining Medweb, DICOM, and web-browser software using desktop personal computers (PCs), an easily accessible picture archiving and communications system (PACS) is available to radiologists and referring physicians. Multiple monitors are easily configured and managed using Windows98. This system can sustain changes and can be extended to provide variable functions using inexpensive PCs.

Interpretation of periapical lesions comparing conventional, direct digital, and telephonically transmitted radiographic images

The purpose of this study was to evaluate direct digital radiography (DDR) and telephonically transmitted images versus conventional radiography in the interpretation of artificial periapical bone lesions. Five teeth were chosen from four cadaver jaw specimens. Three types of DDR images were evaluated: DDR stored images, DDR transmitted images, and DDR reversed images. A total of 150 DDR computer monitor images and 56 D-speed film images were evaluated by three endodontists and one endodontic graduate student. The Wilcoxon signed-ranks test was used for statistical analyses of the results. DDR reversed images were statistically inferior to DDR stored images, DDR transmitted images, and conventional radiography images (p < 0.0001). There were no statistically significant differences between DDR stored images, DDR transmitted images, and conventional film images in the ability of the evaluator to identify artificial periapical bone lesions (p > 0.05).

Computed dental radiography system versus conventional dental X-ray films for detection of simulated proximal caries

The diagnostic accuracy of intraoral images obtained with a first generation Computed Dental Radiography (CDR) digital dental imaging system is compared with the diagnostic accuracy of conventional dental x-ray film images using a receiver operating characteristics (ROC) analysis. Fifteen dentition phantoms were constructed. Each contained 4 teeth, consisting of premolar and molar teeth with 6 proximal surfaces. Mechanical defects were created randomly on the proximal surfaces and plugged with dentine powder to simulate caries. Fifteen images of each modality were rated by nine dentists in separate sessions according to their confidence in their ability to detect the simulated caries. The images examined were as follows: original CDR images, CDR images magnified 2×, CDR images magnified 4 ×, Ektaspeed Plus dental x-ray film images, and Ultraspeed dental x-ray film images, both unmagnified and magnified 2 ×. A series of ROC curves indicated the limited usefulness of magnification for the CDR system, and consistently similar success in detecting simulated proximal caries for original CDR images and original film images. The magnification of original film images did not always promote greater success than that obtained with the original film images.

Image quality of an intraoral storage phosphor imaging system for normal anatomical structures, proximal caries and decalcified bone changes

The delineation of normal anatomical structures and the detection of minute changes in proximal caries in extracted teeth and in bone treated with a chemical decalcification process were investigated using the intraoral digital imaging system, Digora. Cathode ray tube (CRT)-output images obtained with the Digora system, film-output images prepared through computed radiography, and conventional periapical film (conventional film) images of the various experimental materials were evaluated visually. The accuracy of detection of the enamel-dentin junction of normal teeth was greater with Digora CRT- and film-output images than with conventional film images. However, no marked differences were observed in the diagnostic power in the examination of other materials. The detection of proximal caries was similar for all three image types, regardless of the caries depth. In the decalcified bone specimens, the increases in the area under the receiver operating characteristic curve (Az value) corresponded to the degree of decalcification, and no differences were observed in the detection of bone changes among the CRT-output, film-output, and conventionals film images. These results suggest that the diagnostic value of Digora system, output primarily as CRT images, is comparable to that of film-output images and conventional film images, and that it is potentially applicable to clinical diagnosis.

ESTIMATING DISTANCES ON DIRECT DIGITAL IMAGES AND CONVENTIONAL RADIOGRAPHS

Digital images produced by direct sensor systems are much larger than conventional radiographic film images because of monitor resolution and digital image file sizes. This difference in size may introduce difficulties when estimating distances (for example, during endodontic treatment). The aim of this study was to compare observers' estimates of distances on digital images with those of conventional radiographs.