• Imaging Science in Dentistry
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• v.35 no.4
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• pp.203-205
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• 2005

Purpose: This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Materials and Methods: Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician (s) at each school to set the exposure parameters and aiming the x-ray tube for the periapical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter : Unfors instruments, Billdal, Sweden). Results: The median dose was $491.2{\mu}Gy$ for digital radiography and $1,205.0{\mu}Gy$ for film radiography. The skin entrance dose in digital radiography was significantly lower than that of film radiography (p<0.05). Conclusion: Fifty-nine percent skin entrance dose reduction with digital periapical radiography was achieved over the film radiography in Korean dental schools.

• Journal of Welding and Joining
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• v.27 no.2
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• pp.51-56
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• 2009

Film based radiography imaging technique has been applied to the non-destructive test in medical, aircraft, and power industries contributing to the development of the industries. However, the complex process for imaging and analysis has increasingly demanded the reformation of the radiography test. A digital radiography imaging technologies has been com out from the demand. This study was mainly focused on the assessment on the accuracy for the each image from digital radiography test and film radiography test was proven to crate a better image in sensitivity than film radiography test. In the IQI(Image quality indicator) transmission test, one or two more line can be seen in digital image than in film image. When applying to the boiler tube weld, film image is detectable to the 1.0mm depth flaw; and digital image to the 0.5mm depth flaw. As a result of this study, digital radiography technology is determined to enhance the image quality, compared to film radiography technologies

• Imaging Science in Dentistry
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• v.33 no.1
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• pp.27-33
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• 2003

Purpose : The purpose of this experiment was to evaluate the diagnostic ability of a CCD-based digital system (CDX-2000HQ) in the detection of incipient dental caries. Materials and Methods : 93 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were radiographed using 4 imaging methods. Automatically processed No.2 Insight film (Eastman Kodak Co., U.S.A.) was used for conventional radiography, scanned images of conventional radiograms for indirect digital radiography were used. For the direct digital radiography, the CDX-2000HQ CCD system (Biomedisys Co. Korea) was used. The subtraction images were made from two direct digital images by Sunny program in the CDX-2000HQ system. Two radiologists and three endodontists examined the presence of lesions using a five-point confidence scale and compared the diagnostic ability by ROC (Receiver Operating Characteristic) analysis and one way ANOV A test. Results: The mean ROC areas of conventional radiography, indirect digital radiography, direct digital radiography, and digital subtraction radiography were 0.9093, 0.9102, 0.9184, and 0.9056, respectively. The diagnostic ability of direct digital radiography was better than the other imaging modalities, but there were no statistical differences among these imaging modalities (p > 0.05). Coclusion : These results indicate that new CCD-based digital systems (CDX-2000HQ) have the potential to serve as an alternative to conventional radiography in the detection of incipient dental caries.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.25-30
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• 2011

This study is made to provide with a method for correcting the geometric distortion of the digital radiography image by analytical approach based upon the inverse square law and Beer's law. This study is aimed to find out and improve a mathematic model of nonlinear type. Variations in the alignment of the X-ray source, the object, and imaging plate affect digital radiography images. A model which is expressed in parameter values; e.g, angle, position, absorption coefficient, length, width and pixel account of radiography source, is developed so as to match the sample image. For the best correction of the digital image that is the most similar to the model image, a correction technique based upon tangent is developed; then applied to the digital radiography images of steel tubes. As a result, the image correction is confirmed to be made successfully.

• Imaging Science in Dentistry
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• v.41 no.1
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• pp.7-10
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• 2011

Purpose : The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Materials and Methods : Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-$15^{\circ}$, 15-$30^{\circ}$, > $30^{\circ}$). After the placement of a 15 K-file, radiographs were taken with a conventional film (Fspeed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. Results : There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. Conclusion : The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.113-121
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• 2002

Conventional intraoral radiography continues to be the most widely used image modality for the diagnosis of dental caries. But, conventional intraoral radiography has several shortcomings, including the difficulty of exposing and processing intraoral film of consistently acceptable quality. In addition, radiographic retaking that was the result of processing errors, may result in increased discomfort and radiation dose to the patient. Recently, various digital radiographies substitute for conventional intraoral radiography to overcome these disadvantages. The advantages of digital radiography are numerous. One of advantages Is the elimination of processing errors. In addition, the radiation dose for digital system is approximately 20% to 25% of that required for conventional intraoral radiography Another potential advantage of digital imaging is the ability to perform image quality enhancements such as contrast and density modulation, which may increase diagnostic accuracy. The purpose of this study was to compare the diagnostic ability of artificial proximal defects to conventional intraoral radiography, direct digital image(CDX2000HQ$^{\circledR}$) and indirect digital image(Digora$^{\circledR}$). Artificial defects were made in proximal surfaces of 60 extracted human molars using #1/2, #1, #2 round bur. Five dentists assessed proximal defects on conventional intraoral radiography, direct digital image(CDX2000HQ$^{\circledR}$) and indirect digital image(Digora$^{\circledR}$). ROC(Receiver Operating Characteristic) analysis and Two-way ANOVA test were used for the evaluation of detectability, and following results were acquired. 1. The mean ROC area of conventional intraoral radiography, direct digital image(CDX2000HQ$^{\circledR}$) and indirect digital Image(Digora$^{\circledR}$) were 0.6766, 0.7538, 0.6791(Grade I), 0.7176, 0.7594, 0.7361(Grade II), and 0.7449, 0.7608, 0.7414(Grade III), respectively. 2. Diagnostic ability of direct digital image was higher than other image modalities. But, there was no statistically significant difference among other imaging modalities for Grade I, II, III lesion(p>0.05). In conclusion, when direct and indirect digital system are comparable with conventional intraoral radiography. these systems may be considered an alternative of conventional intraoral radiography for the diagnosis of proximal surface caries.

• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.432-438
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• 2017

PURPOSE. The purpose of this study was to evaluate the in vitro validity of quantitative light-induced fluorescence-digital (QLF-D) and laser fluorescence (DIAGNOdent) for assessing proximal caries in extracted premolars, using digital radiography as reference method. MATERIALS AND METHODS. A total of 102 extracted premolars with similar lengths and shapes were used. A single operator conducted all the examinations using three different detection methods (bitewing radiography, QLF-D, and DIAGNOdent). The bitewing x-ray scale, QLF-D fluorescence loss (${\Delta}F$), and DIAGNOdent peak readings were compared and statistically analyzed. RESULTS. Each method showed an excellent reliability. The correlation coefficient between bitewing radiography and QLF-D, DIAGNOdent were -0.644 and 0.448, respectively, while the value between QLF-D and DIAGNOdent was -0.382. The kappa statistics for bitewing radiography and QLF-D had a higher diagnosis consensus than those for bitewing radiography and DIAGNOdent. The QLF-D was moderately to highly accurate (AUC = 0.753 - 0.908), while DIAGNOdent was moderately to less accurate (AUC = 0.622 - 0.784). All detection methods showed statistically significant correlation and high correlation between the bitewing radiography and QLF-D. CONCLUSION. QLF-D was found to be a valid and reliable alternative diagnostic method to digital bitewing radiography for in vitro detection of proximal caries.

• Journal of Power System Engineering
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• v.12 no.6
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• pp.70-77
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• 2008

The purpose of this study is to compare the quality of digital radiography image with that of classical film images for welded structure in power plants. The CMOS(Complementary Metal Oxide Semiconductor) flat panel detecter and Agfa D5 film are used to image flaw specimens respectively. In the test, CMOS flat panel detector has been determined to have a better image than that of film image. In the IQI(Image Quality Indicator) transmission test, one or two more line can be seen in digital image than in film image. Digital Radiography Test enabled to successfully detect all defects on the weld specimens fabricated with real reheat stem pipe and boiler tube as well. In the specific comparison test, Digital radiography test detected micro flaws in the size of 0.5 mm in length by 0.5 mm in depth. However, film test has limited it to 1.0 mm in length by 1.0 mm in depth. As a result of this study, digital radiography technology is estimated well enough to perform the inspection in the industry with far more cost effective way, compared to the classical film test.

• Imaging Science in Dentistry
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• v.40 no.1
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• pp.9-14
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• 2010

Purpose : We evaluated the absorbed doses to the organs and calculated the effective doses when using the digital panoramic radiography. Materials and Methods : The absorbed dose averages in major organs of oral and maxillofacial region were measured using the Dental head phantom (CIRS Co., USA), $^nLi_2B_4O_7$ TLD chip and UD-716AGL dosimeter (Matsushita Electric Industrial Co., JPN) when performing indirect and direct digital panoramic radiography. Effective doses were calculated from correspond to ICRP 2007 recommendations for two panoramic radiography. Results : The absorbed dose average on indirect and direct digital panoramic radiography was highest in parotid glands as measured 1259.6 mGy and 680.7 mGy respectively. Absorbed dose average in another organs were high in order of esophagus, submandibular gland, tongue and thyroid gland on both types of digital panoramic radiography. The absorbed dose average was higher on indirect type than direct one (p<0.05). The effective dose was higher on indirect type than direct one as measured 13.28 mSv and 8.70 mSv respectively. Conclusion : The absorbed doses in salivary gland and oral mucosa were high. However, thyroid gland also demands the attention on radiography due to high tissue weighting factor in spite of the low absorbed dose.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.67-75
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• 1995

The progress of periodontal disease and the wound healing process after treatment result in alveolar bone bone change. So, detection of it is very important in the diagnosis and the radiograph of periodontal disease. Various effects have been made to assess the subtle alveolar bone change and digital subtraction radiography (DSR) has been reported to be the best method in evaluating it qualitatively and quantitatively. The present study was performed to estimate the detectable alveolar bone change qualitatively with digital subtraction radiography. For the in vitro study, 10 intraoral standard radiographs were taken from porcine dry mandible which a rectangular cortical bone chip of 0.1mm to 1.0mm thickness with 0.1mm increment was attached on the buccal surface. The radiographs without and with bone plates were reviewed at the same time by 10 observers and requested to detect the presence of cortical bone plates. Digital Subtraction radiograph was reviewed subsequently by using the DSR system(digital converter-256 grey-levels,DT 2851,Data Translation Co., U.S.A;IBM 386 ; CCD camera, FOTOVIX, Tamrom Co., Japan). The detectable thickness of cortical bone plate was O.4mm on the intraoral radiograph and 0.2mm on the subtaction images. For the human study, radiographs were taken from patients by using intraoral film holding device and aluminum reference wedge before and 3 month after bone graft and 1 week after osteoplasty. The grey level change was estimated in the subtraction images and calculated to aluminum equivalent thickness. The grey level of the grafted site was higher that that of healthy controls. Average grey levels of change on healthy controls were O.48mm aluminum equivalent. However, the amount of changes in grafted sites were 1.87mm aluminum thickness equivalent and in the site of osteoplasty were -1.49mm aluminum thickness equivalent. In conclusion, digital subtraction radiography was more effective in detecting as subtle change of alveolar bone than intraoral standard radiography. With the aid of quantitative analysis of digital subtraction radiography, alveolar bone resorption of apposition can be estimated during diagnosis and treatment of periodontally diseased patients.