Optimization of exposure in panoramic radiography while maintaining image quality using adaptive filtering

EFFECTIVE DOSES AND RADIATION RISKS FROM COMMON DENTAL RADIOGRAPHIC, PANORAMIC AND CBCT EXAMINATIONS

This study was aimed at the estimation of the effective doses and radiation risks from dental X-ray examinations based on the data collection in St. Petersburg and the Leningrad Region. The range of mean values of effective doses for intraoral examinations on the X-ray units with film detectors was from 3.5 to 8.2 μSv and for the units with digital detectors-from 1.2 to 2.5 μSv. The mean effective doses for panoramic examinations were 22.9 μSv and for cone-beam computed tomography (CBCT)-530.6 μSv, respectively. The highest detriment-adjusted lifetime risk values were estimated for the 20-24-year-old age group: 40.8 × 10-6 in females and 32.7 × 10-6 in males for CBCT. Effective doses in St. Petersburg and Leningrad region were comparable or higher compared with the published data.

A comparison of perceived diagnostic image quality in direct digital panoramic images between standard and advanced external GOP image processing

Objective: The objective of the present study was to study the effect of adaptive image processing (GOP processing) on the visibility of anatomical structures in direct digital panoramic images. Material and methods: The study comprised panoramic images of 50 consecutive adult individuals aged 18-60 years. Nine dentists working with dental radiology compared the structural image quality of all standard-processed and GOP-processed panoramic images for six anatomical structures, using a six-point scale for visual grading characteristics analysis. Results: For all anatomic structures a statistically significant difference in favour of the GOP was found. Conclusions: The present study shows that it is possible to improve perceived diagnostic image quality of direct digital panoramic radiography using GOP technology compared to the manufacturers' standard processing. Manufacturers' image-processing programs can be further developed, as there is a possibility of improving the perceived diagnostic content of an image with external processing.

The missing link in image quality assessment in digital dental radiography

Digital radiography is gaining popularity among general dental practitioners. It includes digital intraoral radiography, digital panoramic radiography, digital cephalography, and cone-beam computed tomography. In this study, we focused on the methods to assess image quality of these techniques, except for digital cephalography, in the light of historical issues. We stressed on the importance of the development of a standardized phantom and quantitative analysis of diagnostic image quality using it, especially in the aspect of psychophysical properties of these digital systems. There is no missing link in the image quality assessment in digital intraoral radiography and cone-beam computed tomography in dental use. However, there are missing links between physical and diagnostic image qualities in panoramic radiography. The development of a semi-standardized phantom and the corresponding quantitative analysis method for image quality may be required in digital panoramic radiography. Quantitative image quality assessment using a standardized phantom will also be promising in the future artificial intelligence era.

Can adaptive post-processing of storage phosphor plate panoramic radiographs provide better image quality? A comparison of anatomical image quality of panoramic radiographs before and after adaptive processing

OBJECTIVE

The objective of the present study was to study the effect of adaptive image processing on the visibility of anatomical structures in storage phosphor plate (SPP) panoramic images.

MATERIALS AND METHODS

Three hundred SPP panoramic X-ray radiographs of children and adolescents were used. The radiographs were post-processed using general operator processor (GOP) technology, resulting in both a standard-processed and a GOP-processed radiograph. Four specialists in dental radiology compared the structural image quality of all standard-processed and GOP-processed panorama images for six anatomical structures, using a six-point scale for visual grading characteristics (VGC) analysis.

RESULTS

For three of the anatomic structures - the root canal space of the mandibular left first premolar, mandibular canal left side and periodontal ligament space of the mandibular right first molar - there was a statistically significant difference to the GOP's advantage. For the three remaining structures - dentino-enamel junction of the maxillary right first molar, crista alveolaris of the mandibular left molar area and floor of maxillary sinus right side - no significant difference between standard processing and GOP processing was obtained.

CONCLUSIONS

The study demonstrates that it is possible to improve the quality of SPP radiographs and the visibility of anatomical structures by using the GOP technique. Manufacturers' image-processing programs can be further developed, as there is a possibility of improving the diagnostic content of an image with external processing.

Image quality assessment of pre-processed and post-processed digital panoramic radiographs in paediatric patients with mixed dentition

Purpose

To determine the impact of an image processing technique on diagnostic accuracy of digital panoramic radiographs for the assessment of anatomical structures in paediatric patients with mixed dentition.

Materials and Methods

The study consisted of 50 digital panoramic radiographs of children aged from 6 to 12 years, which were later on processed using a dedicated image processing method. A modified clinical image quality evaluation chart was used to evaluate the diagnostic accuracy of anatomical structures in maxillary and mandibular anterior and maxillary premolar region of processed images.

Results

A statistically significant difference was observed between pre and post-processed evaluation of anatomical structures (P<0.05) in the maxillary and mandibular anterior region. The anterior region was found to be more accurate in post-processed images. No significant difference was observed in the maxillary premolar region (P>0.05). The Inter-observer and intra-observer reliability of both pre and post processed images were excellent (>0.82) for anterior region and good (>0.63) for premolar region.

Conclusion

The application of image processing technique in digital panoramic radiography can be considered a reliable method for improving the quality of anatomical structures in paediatric patients with mixed dentition.

VGC ANALYZER: A SOFTWARE FOR STATISTICAL ANALYSIS OF FULLY CROSSED MULTIPLE-READER MULTIPLE-CASE VISUAL GRADING CHARACTERISTICS STUDIES

Visual grading characteristics (VGC) analysis is a non-parametric rank-invariant method for analysis of visual grading data. In VGC analysis, image quality ratings for two different conditions are compared by producing a VGC curve, similar to how the ratings for normal and abnormal cases in receiver operating characteristic (ROC) analysis are used to create an ROC curve. The use of established ROC software for the analysis of VGC data has therefore previously been proposed. However, the ROC analysis is based on the assumption of independence between normal and abnormal cases. In VGC analysis, this independence cannot always be assumed, e.g. if the ratings are based on the same patients imaged under both conditions. A dedicated software intended for analysis of VGC studies, which takes possible dependencies between ratings into account in the statistical analysis of a VGC study, has therefore been developed. The software-VGC Analyzer-determines the area under the VGC curve and its uncertainty using non-parametric resampling techniques. This article gives an introduction to VGC Analyzer, describes the types of analyses that can be performed and instructs the user about the input and output data.