• Journal of The Korean Radiological Technologist Association
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• v.28 no.1
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• pp.112-119
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• 2002

Purpose : The purpose of this study is to evaluate the usefulness, after we compare and analyze the difference about the location of a lesion and the result of diagnosis on chest radiographs(CR) and low dose computed tomography(LDCT) in subjects for healt

• Journal of Veterinary Clinics
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• v.13 no.1
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• pp.87-92
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• 1996

A hemangiosarcoma in a 30 kg, 6-year-old German Shepherd dog showing signs of abdominal distension, anorexia and depression was diagnosed with clinicopathologic examination, abdominal radiographs and ultrasonographic assessmint. In abdominal radiographs, overall abdominal distension was seen. Stomach and some parts of small intestines were deviated caudo-ventrally by enlarged liver. The splenomegaly was also identified and descending colon was dislocated laterally by splenic mass. In ultrasonographic findings, abdominal fluid was identified. Hepatomegaly was seen and it was consisted of multiple, anechoic cysts. The spleen was enlarged and a large round mass with mixed echo pattern at the mid to tail portion of spleen was identified. Grossly, at necropsy, multi-sized cysts in which contained blood and fibrpus materials and some blood were seen in the cross section and it showed hard consistency. Also, lots of small red tumor nodules were dispersed on the serosal surface of the bladder, omentum, mesentery, diaphragm and peritoneum. In abdominal paracentesis, fluid having almost the same properties as circulating blood was identified. The hemoperitoneum was thought to be resulted from the bleeding into peritoneum owing to the rupture of cystic lesions located on the superficial liver area.

• Journal of Korean Dental Science
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• v.10 no.2
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• pp.53-59
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• 2017

Purpose: The objective of the present article is to determine whether there are differences in vertical enlargement ratio among various sites within both jaws in a panoramic radiograph. Materials and Methods: Two hundred and seventy-threeimplant sites in panoramic radiographs were evaluated by two observers. Magnification ratios at various sites in both jaws were calculated and compared with each other. Result: The average vertical enlargement ratio in the panoramic radiograph was 1.264 and this value was larger than original ratio 1.250. Although vertical magnification ratio of maxillary molar area was higher than that of mandibular molar area, every group showed similar magnification ratio in clinical respect. Conclusion: Vertical magnification ratio of the maxillary molar area is statistically higher than that of the mandibular molar area in the panoramic radiograph, but it is clinically negligible.

• Journal of information and communication convergence engineering
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• v.17 no.4
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• pp.274-278
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• 2019

It is important that students are provided opportunities to practice their skills in acquiring radiographic images. However, these opportunities are currently limited because of the risk of radiation exposure. To overcome this limitation, a new augmented reality-based radiography simulator was developed that enables students to practice radiographic techniques as part of self-directed learning without time and space constraints. Subsequently, cross-sectional images of a manikin phantom head obtained via computed tomography were reconstructed into a three-dimensional object. An image marker that could be recognized by a mobile device and could allow users to practice dental radiography techniques was devised. The three-dimensional object was augmented to the mobile device; consequently, among 106 stored dental radiographs on the device, a radiograph corresponding to specific imaging conditions was opened when users performed radiographic procedures. This technology could improve dental students' understanding of dental anatomy and contribute to improving their competency in acquiring dental radiographs.

• International Journal of Oral Biology
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• v.46 no.4
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• pp.208-213
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• 2021

Increasing the vertical dimesion affects not only functional problems but also the facial appearance. In particular, when restoring the reduced vertical dimension, it is important to evaluate facial appearance because the change affects the patient's aesthetics. Cephalometric radiographs can predict changes in the facial appearance through skeletal and vertical classifications using anatomical indicators, and the changes before and after treatment can be easily observed, which could serve as good data in evaluating treatment success. In this study, comparative evaluation was performed through cephalometric radiography, and the aesthetic and functional improvement was confirmed.

• The Journal of the Korean dental association
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• v.56 no.12
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• pp.707-713
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• 2018

Multiple myeloma is a lymphohematopoietic disorder leading to abnormal hemostasis and significant pathologic changes of skeletal system. It induces multiple circular or oval-shaped radiolucent lesions which are characterized by 'punched-out appearance'. The surrounding trabecular bone normally shows no significant sclerotic reaction. Multiple myeloma patients may visit dental clinics, without perception of the disease themselves, due to discomfort from edema of orofacial region, oral ulcers, tooth mobility, pain or gingival bleeding. Multiple myeloma is susceptible to various complications, including delayed hemostasis and infection, which could occur during routine dental treatment such as periodontal and surgical operation. For radiographic diagnosis of multiple myeloma, common radiologic features of this tumor could be visualized by panoramic radiographs in the dental clinics, and further medical examinations and treatment can be recommended as a result.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.169-174
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• 2023

Gardner syndrome has head and neck manifestations that may be recognized during dental visits. Features such as multiple gnathic osteomas, impacted supernumerary teeth, and multiple foci of idiopathic osteosclerosis can be easily identified on dental radiographs, prompting the clinician to refer the patient for further investigation. A dental examination and routine radiographs play a vital role in revealing the extracolonic presentation of Gardner syndrome, which facilitates timely screening and detection of colorectal cancer and other malignancies associated with this condition. This report discusses the case of a 50-year-old Caucasian man who presented with a hard swelling of the left angle of the mandible and was diagnosed with Gardner syndrome based on abnormal findings from an oral examination, dental imaging, and medical and family history.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.169-174
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• 2020

Purpose: Periodontal disease causes tooth loss and is associated with cardiovascular diseases, diabetes, and rheumatoid arthritis. The present study proposes using a deep learning-based object detection method to identify periodontally compromised teeth on digital panoramic radiographs. A faster regional convolutional neural network (faster R-CNN) which is a state-of-the-art deep detection network, was adapted from the natural image domain using a small annotated clinical data- set. Materials and Methods: In total, 100 digital panoramic radiographs of periodontally compromised patients were retrospectively collected from our hospital's information system and augmented. The periodontally compromised teeth found in each image were annotated by experts in periodontology to obtain the ground truth. The Keras library, which is written in Python, was used to train and test the model on a single NVidia 1080Ti GPU. The faster R-CNN model used a pretrained ResNet architecture. Results: The average precision rate of 0.81 demonstrated that there was a significant region of overlap between the predicted regions and the ground truth. The average recall rate of 0.80 showed that the periodontally compromised teeth regions generated by the detection method excluded healthiest teeth areas. In addition, the model achieved a sensitivity of 0.84, a specificity of 0.88 and an F-measure of 0.81. Conclusion: The faster R-CNN trained on a limited amount of labeled imaging data performed satisfactorily in detecting periodontally compromised teeth. The application of a faster R-CNN to assist in the detection of periodontally compromised teeth may reduce diagnostic effort by saving assessment time and allowing automated screening documentation.

• 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.

• Journal of Korean Foot and Ankle Society
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• v.19 no.4
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• pp.165-170
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• 2015

Purpose: The purpose of this study is to analyze the measurement differences of simple radiographs according to radiation projection angle using a phantom and to propose methods for objective analysis of simple radiographs. Materials and Methods: We took simple radiographs with different projection angles using a C-arm image intensifier and measured five parameters of the foot on the simple radiographic images. Five parameters include lateral tibiocalcaneal angle, lateral talocalcaneal angle, naviculocuboid overlap, lateral talo-first metatarsal angle, and lateral calcaneo-first metatarsal angle. Intraobserver and interobserver reliability were verified, and then intraclass correlations of parameters were analyzed. Results: Radiographic parameters of the foot showed high intraobserver and interobserver reliability. Lateral tibiocalcaneal angle has a strong negative linear relationship with rotation and a moderate negative linear relationship with tilt. Lateral talocalcaneal angle has a moderate positive linear relationship with rotation and a strong positive linear relationship with tilt. Naviculocuboid overlap has a strong positive linear relationship with rotation and a moderate positive linear relationship with tilt. Lateral talo-first metatarsal angle does not have a linear relationship with rotation and a moderate negative linear relationship with tilt. Lateral calcaneo-first metatarsal angle has a moderate positive linear relationship with rotation and tilt. Conclusion: More precise evaluation of the foot with a simple radiograph can be performed by understanding the changes of radiographic parameters according to radiation projection angle.