• Journal of radiological science and technology
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• v.37 no.3
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• pp.169-175
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• 2014

According to database of medical institutions of health insurance review & assessment service in 2013, 1118 hospitals and clinics have department of radiology in Korea. And there are CT, fluoroscopic and general radiographic equipment in those hospitals. Above all, general radiographic equipment is the most commonly used in the radiology department. And most of the general radiographic equipment are changing the digital radiography system from the film-screen types of the radiography system nowadays. However, most of the digital radiography department are used the film-screen types of the radiography system. Therefore, in this study, we confirmed present conditions of technical items for general radiography used in hospital and research on general radiographic techniques in domestic medical institutions. We analyzed 26 radiography projection method including chest, skull, spine and pelvis which are generally used in the radiography department.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.184-190
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• 2012

Purpose: The purpose of this study was to measure the absorbed dose and to calculate the effective dose for one periapical radiography using the portable and wall type dental X-ray machines. Materials and methods: Thermoluminescent chips were placed at 25 sites throughout the layers of the head and neck of a tissue-equivalent human skull phantom. The man phantom was exposed with the portable and wall type dental X-ray machines. For one periapical radiography taken by portable dental X-ray machine, the exposure setting was 60 kVp, 2 mA and 0.2 seconds, while for one periapical radiography taken by wall type dental X-ray machine, exposure setting was 70 kVp, 8 mA and 0.074 seconds. Absorbed dose measurements were performed and equivalent doses to individual organs were summed using ICRP 103 to calculate effective dose. Results: In the upper anterior periapical radiography using portable dental X-ray machine and in the lower posterior periapical radiography using both machines, the highest absorbed dose was recorded at the mandible body. The effective dose in upper anterior periapical radiography using portable and wall type dental X-ray machines was $4{\mu}Sv$, $2{\mu}Sv$, respectively. In the lower posterior periapical radiography, the effective dose for each portable and wall type dental X-ray machines was $6{\mu}Sv$, $2{\mu}Sv$. Conclusion: It was recommended that the operator use prudently potable dental X-ray machine because that the effective dose in the periapical radiography using wall type dental X-ray machine was lower than that in the periapical radiography using portable dental X-ray machine.

• 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.

• Tuberculosis and Respiratory Diseases
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• v.59 no.4
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• pp.356-360
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• 2005

Background : This study examined the clinical utility of using indirect chest radiography during a physical examination of new conscripts for determine the presence of pulmonary tuberculosis. Methods : Over an eight-month period, this study examined 25386 people who underwent a physical examination after conscription. The abnormal findings on mass miniature radiography were followed-up using direct chest radiography. The positive predictive value of mass miniature radiography and direct chest radiography was compared. The incidence, degree of infiltration and clinical outcome of active pulmonary tuberculosis were also evaluated during a follow-up examination. Results : The positive rate of mass miniature radiography was 1.19% (n=302). Various lesions were identified: Parenchymal lesions (n=109), mediastinal lesions (n=6), cardiovascular lesions (n=45), pleural lesions (n=49), bony lesions (n=90) and miscellaneous lesions (n=7). The incidence of active pulmonary tuberculosis by mass miniature radiography was 0.26% (n=67). The first diagnosis was made in 50 people; active pulmonary tuberculosis (n=42), pneumonia (n=1), a mediastinal mass (n=1), a rib fracture (n=2) and a pneumothorax (n=4). Most cases of active pulmonary tuberculosis were mildly infiltrated and either improved or were cured by the follow-up examination. Conclusion : Although mass miniature radiography in a physical examination after conscription has limitations, but it is a useful means for detecting the presence of early disease, particularly in active pulmonary tuberculosis.

• Journal of Power System Engineering
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• v.13 no.5
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• pp.95-102
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• 2009

A steam generator (boiler) in thermal power plants, consisting of more than 30,000 parts and components, can lead to the plant shutdown with damage to even the small part of the components; esp., like weld failures on boiler tubes. Consequently it is greatly demanded to improve the quality of the weld on the boiler tube for the stable operation of the power plants. Because of the feature of the welding, which is done past by melting the work pieces and adding a filler material that cools to become a strong coalescence, there is a great possibility that weld failures take place. As a result, it is regulated to make a non-destructive testing, like radiography test, to detect defects and flaws in the weld. The current film radiography test provides a lower image quality exceeding 2.0% of a basic quality level for a penetrameter, it is very likely to fail to detect micro defect. As a result, the prevention for the boiler tube failure has not been made effectively. In this study, computed radiography technology has been applied as a digital radiography test to the boiler tube weld, and Se-75 radiation source was used to improve the image quality, instead of Ir-192 source. As a result of this study, it is proven to save the time and cost for test and to enhance the quality level of penetrameter penetrating image, which enables to upgrade the quality of radiography test to the boiler tube weld.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.783-790
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• 2011

Objectives : The purpose of this study was to examine students' difficulties in the process of oral radiography practice, to raise awareness of the importance and necessity of oral radiography and decipher, and to provide some information on effective ways of oral radiography practice. Methods : The subjects in this study were 285 dental hygiene students at K college, who included 153 sophomores and 132 graduates-to-be from June to November, 2010. Results : 1. The parts of the anatomy structure that they found it most difficult to decipher were maxillary molar(25.3%) and lower molar(22.1%). 2. They made during oral radiography was an improper film positioning(35.1%). 3. The part of bisecting technique was adjusting vertical and horizontal angles(53.0%). 4. The part of paralleling technique was positioning XCP in the oral cavity(44.2%). 5. The part of bite-wing technique was adjusting vertical and horizontal angles(38.2%). 6. The part of occlusion technique was positioning film and tube head(36.5%). 7. The part of panorama technique was finding out program setting(42.5%). Conclusions : The findings of the study indicated that in terms of anatomy structure decipher, it's especially difficult to decipher maxillary molar and lower molar, and that film positioning was difficult to do in the process of oral radiography. What difficulties they faced in applying each kind of oral radiography techniques and which part of the oral cavity they found it hard to radiograph were analyzed as well in this study. Given the findings of the study, more intensive practice is required to help students to acquire accurate oral radiography techniques to ensure their successful job performance in the future.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.103-112
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• 1990

The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-2l0 Head & Neck Section/sup R/, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70Kvp and 15mA, 1/4 second (8 inch cone) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.261-269
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• 1998

With the CT findings as gold standard, the sensitivity, the specificity, and the diagnostic accuracy of Waters' radiography and Waters' radiography with panoramic radiography were compared in the diagnosis of antral mucosal thickening of 16 patients. Three oral radiologists and three non-oral radiologists interpreted the Waters' radiographs and after 4 weeks, interpreted the Waters' radiographs and panoramic radiographs simultaneously. The interpretation point was the existence or the non-existence of the mucosal thickening on the medial, the posterolateral, the floor, and the roof of maxillary sinus. The obtained results were as followed : 1. In oral radiologist group, the sensitivity, specificity and diagnostic accuracy of Waters' film were 0.7250, 0.8489 and 0.7578 respectively. 2. The sensitivity and the diagnostic accuracy in oral radiologist group were higher than those of non-oral radiologist group (P<0.05), but there was no significant difference between two groups in the specificity (P>0.05), 3. There was no significant difference of the diagnostic abilities except the specificity in oral radiologist group between Waters' radiography and Waters' radiography with panoramic radiography (P>0.05). 4. The sensitivity and the diagnostic accuracy were the highest in the case of medial wall interpretation, the specificity was the highest in the posterolateral wall. 5. In the posterolateral wall and the floor, the sensitivity and the diagnostic accuracy of oral radiologist group were higher than those of non-oral radiologist group (P<0.05).

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.269-275
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• 2018

Purpose: The aim of this study was to evaluate the correlations between measurements made using panoramic radiography and cone-beam computed tomography (CBCT) based on certain anatomical landmarks of the jaws, with the goal of preventing complications due to inaccurate measurements in the pre-surgical planning phase of dental implant placement. Materials and Methods: A total of 56 individuals who underwent panoramic radiography and a CBCT evaluation before dental implant surgery were enrolled in the study. Measurements were performed to identify the shortest vertical distance between the alveolar crest and neighboring anatomical structures, including the maxillary sinus, nasal floor, mandibular canal, and foramen mentale. The differences between the measurements on panoramic radiography and CBCT images were statistically analyzed. Results: Statistically significant differences were observed between the measurements on panoramic radiography and CBCT for all anatomical structures (P<.05). The correlation coefficients (r) between the paired samples obtained from panoramic radiography and CBCT were closely correlated (P<.05), with r values varying from 0.921 and 0.979 for different anatomical regions. Conclusion: The results of this study support the idea that panoramic radiography might provide sufficient information on bone height for preoperative implant planning in routine cases or when CBCT is unavailable. However, an additional CBCT evaluation might be helpful in cases where a safety margin cannot be respected due to insufficient bone height.

• Journal of Radiation Protection and Research
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• v.47 no.2
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• pp.93-98
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• 2022

Background: This study aims to derive the characteristics of each work type for industrial radiography based on empirical evidence through expert advice and a survey of radiation workers of various types of industrial radiography. Materials and Methods: According to a Korean report, work types of industrial radiography are classified into indoor tests, underground pipe tests, tests in a shielded room (radiographic testing [RT] room test), outdoor field tests, and outdoor large structure tests. For each work type, exposure geometry and radiation sources were mainly identified through the expert advice and workers' survey as reliable empirical evidence. Results and Discussion: The expert advice and survey results were consistent as the proportion of the work types were high in the order of RT room test, outdoor large structure test, underground pipe test, outdoor field test, and indoor test. The outdoor large structure test is the highest exposure risk work type in the industrial radiography. In most types of industrial radiography, radiation workers generally used ¹⁹²Ir as the main source. In the results of the survey, the portion of sources was high in the order of ¹⁹²Ir, X-ray generator, ⁶⁰Co, and ⁷⁵Se. As the exposure geometry, the antero-posterior geometry is dominant, and the rotational and isotropic geometry should be also considered with the work type. Conclusion: In this study, through expert advice and a survey, the external exposure characteristics for each work type of industrial radiography workers were derived. This information will be used in the reconstruction of organ dose for health effects assessment of Korean radiation workers.