scholarly journals Reproducibility of pixel values for two photostimulable phosphor plates in consecutive standardized scannings

2006 ◽  
Vol 20 (3) ◽  
pp. 207-213 ◽  
Author(s):  
Patrícia Freitas ◽  
Renato Yassutaka Faria Yaedú ◽  
Izabel Regina Fischer Rubira-Bullen ◽  
Maurício Escarpinati ◽  
Marcelo Costa Vieira ◽  
...  
Keyword(s):  
Digital Image ◽  
X Rays ◽  
X Ray ◽  
Scanning Time ◽  
Quantitative Studies ◽  
Significant Difference ◽  
Photostimulable Phosphor ◽  
Phosphor Plates

The objective of the present study was to determine the reproducibility of the pixel values obtained with the Digora system (Soredex, Finland). Exposures were standardized, with variation in exposure and scanning time of two photostimulable phosphor plates containing a stepwedge image. The smallest variation in pixel values ranged from 50 to 75%, with the widest variations being observed in less dense steps. A significant difference in pixel values was observed in terms of X-ray exposure and scanning times and between the two plates themselves (ANOVA, p < 0.01). Using the present methodology, the reproducibility of pixel values was not satisfactory for the tested white photostimulable plates. This wide variation in digitalization might be influenced by the amount of X-rays that sensitized the plates. It may be important to establish the reproducibility of the pixel values in quantitative studies using digital image.

scholarly journals Analysis of the deterioration of photostimulable phosphor plates

2020 ◽  
Vol 49 (6) ◽  
pp. 20190500
Author(s):  
Gustavo Nascimento de Souza-Pinto ◽  
Gustavo Machado Santaella ◽  
Amanda Achkar Coli ◽  
Anne Caroline Oenning ◽  
Francisco Haiter-Neto
Keyword(s):  
Region Of Interest ◽  
Objective Analysis ◽  
X Rays ◽  
X Ray ◽  
Photostimulable Phosphor ◽  
The Mean ◽  
Phosphor Plates ◽  
Gray Values

Objectives: To assess, objectively to determine the deterioration of the photostimulable phosphor plates (PSPs) after several acquisitions. Methods: Two new PSPs without preliminary use were exposed with an intraoral X-ray unit, and the EXPRESS® (Instrumentarium Imaging, Tuusula, Finland) unit was used for scanning of the PSPs. A 12-stepwedge aluminum scale were used superimposed with the PSPs during the X-rays exposures to perform the objective analyses. Objective analysis was carried out by mean gray values using the Image J software through a region of interest (ROI) of 0.1 × 0.1 mm, and the data were analyzed statistically using ANOVA. Results: For each, the Express® PSP a total of 1800 images were acquired during 60 days. The objective analysis showed loss of the mean gray values between the initial and final images. Besides, the percentage of mean gray values’ loss was between 0.7%, for the thickest step, and 8.4%, for the lowest thickness step. Conclusion: After many X-ray exposures of the Express® PSP a singular deterioration in the mean gray values could be observed.

scholarly journals Integration of Dental Implants in Conjunction with EDTA-Conditioned Dentin Grafts: An Experimental Study

2021 ◽  
Vol 9 (6) ◽  
pp. 63
Author(s):  
Payam Farzad ◽  
Ted Lundgren ◽  
Adel Al-Asfour ◽  
Lars Andersson ◽  
Christer Dahlin
Keyword(s):  
Direct Contact ◽  
Mineral Content ◽  
X Rays ◽  
X Ray ◽  
Dentin Surface ◽  
Significant Difference ◽  
C And N ◽  
Micro Implants ◽  
Demineralized Dentin

This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis.

scholarly journals Digital Image Segmentation Resulting from X-Rays of Covid Patients using K-Means and Extraction Features Method

2021 ◽  
Vol 3 (1) ◽  
pp. 25-28
Author(s):  
Dhian Satria Yudha Kartika ◽  
Anita Wulansari ◽  
Hendra Maulana ◽  
Eristya Maya Safitri ◽  
Faisal Muttaqin
Keyword(s):  
Digital Image ◽  
Confusion Matrix ◽  
Health Sector ◽  
X Rays ◽  
Social Psychological ◽  
Uniform Size ◽  
X Ray ◽  
X Ray Imaging ◽  
Standard Quality ◽  
Chest X Ray

The COVID-19 pandemic has significant impact on people's lives such as economic, social, psychological and health conditions. The health sector, which is spearheading the handling of the outbreak, has conducted a lot of research and trials related to COVID-19. Coughing is a common symptoms among humans affected by COVID-19 in earlier stage. The first step when a patient shows symptoms of COVID-19 was to conduct a chest x-ray imaging. The chest x-rayss can be used as a digital image dataset for analysing  the spread of the virus that enters the lungs or respiratory tract. In this study, 864 x-rays  were used as datasets. The images were still raw, taken directly from Covid-19 patients, so there were still a lot of noise. The process to remove unnecessary images would be carried out in the pre-processing stage. The images used as datasets were not mixed with the background which can reduce the value at the next stage. All datasets were made to have a uniform size and pixels to obtain a standard quality and size in order to support the next stage, namely segmentation. The segmentation stage of the x-ray datasets of Covid-19 patients was carried out using the k-means method and feature extraction. The Confusion Matrix method used as testing process. The accuracy value was 78.5%. The results of this testing process were 78.5% of precision value, 78% of recall and  79% for f-measure

Typical errors when performing intraoral periapical x-rays, and their effect on image quality

2020 ◽  
pp. 36-44
Author(s):  
A.P. Arzhantsev
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Digital Image ◽  
Cone Beam ◽  
X Rays ◽  
Post Processing ◽  
X Ray ◽  
Selection Of ◽  
Periapical Radiography

During the study, intraoral periapical images were analyzed in 300 patients. The possibilities of using the methods of radiography and their influence on the quality of the obtained x-ray images were studied. The intraoral periapical radiography was compared with the results of orthopantomography and cone beam computed tomography. To identify the features of the mapping of zones of periapical destruction, 47 experimental x-ray studies were performed on skeletonized jaws with artificial defects in cortical plates. Often encountered errors are: an arbitrary choice of angles of inclination and the centration of the x-ray tube, the wrong location of the x-ray receiver in the patient's mouth, inaccurate installation or poor fixation of the patient's head, inefficient selection of physical and technical conditions of shooting, non-compliance with the conditions of the photo process with analog radiography or post-processing and printing digital image. The characteristic projection distortions of images resulting from these errors are analyzed and illustrated.

Awareness Among Dental Practitioners Towards Radiation Hazards and Protection in Abha City, Saudi Arabia

2020 ◽  
Author(s):  
Hassan Assiri
Keyword(s):  
Saudi Arabia ◽  
Treatment Plan ◽  
X Rays ◽  
Protection Measures ◽  
X Ray ◽  
Sensitive Organ ◽  
Study Results ◽  
Dental Practitioners ◽  
Significant Difference ◽  
Government Hospitals

Background: Dental X-ray is a fundamental part of dentistry. It contributes to the establishment of a definitive diagnosis and the proposed treatment plan. Several modalities are used, ranging from conventional to cone-beam computed tomography with varieties of doses absorbed by the living tissue. Methods: Self-structured questionnaire was established and distributed among 119 dental practitioners working in private and government hospitals through Google® forms. Final-year graduate students of King Khalid University in Abha, Aseer region, Saudi Arabia, were involved as well. Results: A total of 119 participants were included in this prospective survey with a mean ±S.D.ageof 33.30 ± 3.6. There is a significant difference (P<0.05) among the participants in their responses to the most sensitive organ to X-ray, whether the handheld portable X-ray unit was safer than the traditional one, and their knowledge about handheld portable X-ray units. Additionally, there is a significant difference in the responses to whether they used a monitoring device, the distance kept while taking X-rays, and whether they have the patients wear a thyroid collar. Conclusions: The overall extent of awareness of the participants of the dental X-ray hazards, protection measures being followed, and the modes of updating knowledge were found to be satisfactory. The study results will help practitioners to improve their knowledge and to consider protective measures strictly.

Application of synchrotron radiation and Kawai-type apparatus to various studies in high-pressure mineral physics

2002 ◽  
Vol 66 (5) ◽  
pp. 769-790 ◽  
Author(s):  
T. Irifune
Keyword(s):  
High Pressure ◽  
Synchrotron Radiation ◽  
X Rays ◽  
X Ray ◽  
Quantitative Studies ◽  
Deep Interior ◽  
Diamond Anvils ◽  
Sintered Diamond ◽  
Near Future ◽  
Type Apparatus

AbstractA combination of Kawai-type multianvil apparatus and highly brilliant X-rays at the third generation synchrotron radiation facility (SPring-8) in Japan has been successfully applied to various studies in high-pressure mineral sciences such as determinations of phase transition boundaries, P–V–T relations of high-pressure phases, kinetics of phase transitions, structure and viscosity of melts. These studies are now comfortably made at pressures of ˜25 GPa and at temperatures to 2300°C, using the intense X-ray beam and the large capacity of the high-pressure apparatus at SPring-8. Moreover, efforts have been made to further extend the pressure limit using large sintered diamond anvils. Thus in situ X-ray observations are now possible at pressures to 50 GPa with the Kawai-type apparatus, which may be doubled in the near future when the potential of sintered diamond anvils is fully utilized. On the other hand, some problems, such as those related to pressure and temperature measurement, have been manifested in these studies. These should be overcome for further quantitative studies of the mineralogy of the Earth's deep interior based on these techniques.

scholarly journals Investigating the Effect of Different Metal Sheets on Reducing Radiation Behind Intraoral Digital Phosphor Plates During Intraoral Radiography using Gray Value

2020 ◽  
Vol 14 (1) ◽  
pp. 704-710
Author(s):  
Mojdeh Mehdizadeh ◽  
Mohammad Bagher Tavakoli ◽  
Farida Ghazanfari Moghaddam
Keyword(s):  
Stainless Steel ◽  
Test Procedure ◽  
Significant Difference ◽  
Metal Sheets ◽  
Photostimulable Phosphor ◽  
Phosphor Plate ◽  
The Mean ◽  
Photostimulable Phosphor Plate ◽  
Phosphor Plates ◽  
Gray Values

Purpose: To assess the efficacy of metal sheets with different thicknesses on reducing the radiation behind the photostimulable phosphor plate (PSP) during intraoral periapical examinations. Materials and Methods: In this study, a phantom head was used to investigate the effect of using metal sheets of aluminum, stainless steel, and copper with three thicknesses of 0.5, 0.75 and 1mm on reducing the radiation behind PSP. Images were acquired at 66 kVp 8 mA, and 0.16 s using the long-cone paralleling technique. The images were saved and exported to DICOM format without any post-processing. Then, they were transferred to an image processing software (Mimics, Materialize, Leuven, Belgium), and their mean gray values (MGV) were determined. The acquired data were statically analyzed for accessing the significant difference in groups means using ANOVA, and the means of groups were compared using Tukey’s test procedure. Results: The MGV of the second PSP differed significantly from those PSPs slotted with various metals (p<0.001). The MGV for lead and stainless steel at 0.5 mm thickness was insignificant (p = 0.852), but differed significantly from other metals. The MGV for PSPs with 0.75 mm stainless steel and 1 mm copper slots were varied significantly from those of all other PSP and metals. The 1 mm copper group was significantly different from all other groups (p<0.001). Conclusion: Using the mean gray value of the PSP, the use of various metal sheets of different thicknesses could effectively reduce the radiation behind the PSPs during periapical radiographs.

scholarly journals Validity and Reproducibility of the Measurements Obtained Using the Flexicurve Instrument to Evaluate the Angles of Thoracic and Lumbar Curvatures of the Spine in the Sagittal Plane

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Tatiana Scheeren de Oliveira ◽  
Cláudia Tarragô Candotti ◽  
Marcelo La Torre ◽  
Patricia Paula Tonin Pelinson ◽  
Tássia Silveira Furlanetto ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Strong Correlation ◽  
Sagittal Plane ◽  
X Rays ◽  
X Ray ◽  
Graph Paper ◽  
Spinous Processes ◽  
Significant Difference ◽  
Order Polynomial

Objective. to verify the validity and reproducibility of using the flexicurve to measure the angles of the thoracic and lumbar curvatures.Method. 47 subjects were evaluated by: (1) palpation and marking of the spinous processes using lead markers, (2) using X-rays in the sagittal plane to measure the Cobb angles, (3) molding the flexicurve to the spine, and (4) drawing the contour of the flexicurve onto graph paper. The angle of curvature was determined with the flexicurve based on a 3rd order polynomial.Results. No differences were found between the Cobb angles and the angles obtained using the flexicurve in thoracic and lumbar curvatures (). Correlations were strong and significant for the thoracic (, ) and lumbar (, ) curvatures. Excellent and significant correlations were found for both the intraevaluator and interevaluator measurements.Conclusion. The results show that there is no significant difference between the values obtained using the flexicurve and those obtained using the X-ray procedure and that there is a strong correlation between the two methods. This, together with the excellent level of inter- and intraevaluator reproducibility justifies its recommendation for use in clinical practice.

scholarly journals Effect of alternative photostimulable phosphor plates erasing times on subjective digital image quality

2010 ◽  
Vol 39 (1) ◽  
pp. 23-27 ◽  
Author(s):  
DP Melo ◽  
A dos Anjos Pontual ◽  
SM de Almeida ◽  
P S F Campos ◽  
MC Alves ◽  
...  
Keyword(s):  
Image Quality ◽  
Digital Image ◽  
Photostimulable Phosphor ◽  
Phosphor Plates

Comparative Neutron and Synchrotron X-Ray Diffraction Studies to Determine Residual Stress on an As-Welded AA2024 Plate

2005 ◽  
Vol 490-491 ◽  
pp. 223-228 ◽  
Author(s):  
S. Ganguly ◽  
Michael E. Fitzpatrick ◽  
Lyndon Edwards
Keyword(s):  
Residual Stress ◽  
X Rays ◽  
X Ray Diffraction ◽  
Residual Stress Field ◽  
Good Correspondence ◽  
X Ray ◽  
Diffraction Geometry ◽  
Gauge Volume ◽  
Significant Difference ◽  
Similar Sample

The residual stress field in a VPPA welded AA2024 coupon sample was measured by neutron diffraction. A similar sample was measured using synchrotron X-rays to determine the inplane strain directions. The macrostrain obtained from both sources compares well in spite of the significant difference in gauge volume and diffraction geometry. The result confirms the repeatability of the weld process and also shows good correspondence between the two diffraction processes.

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