• Imaging Science in Dentistry
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• 제51권2호
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• pp.137-148
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• 2021

Purpose: This study aimed to assess the computer monitors used for analysis and interpretation of digital radiographs within the clinics of the Oral Health Centre of Western Australia. Materials and Methods: In total, 135 computer monitors(3 brands, 6 models) were assessed by analysing the same radiographic image of a combined 13-step aluminium step wedge and the Artinis CDDent 1.0^® (Artinis Medical Systems B.V.^®, Elst, the Netherlands) test object. The number of steps and cylindrical objects observed on each monitor was recorded along with the monitor's make, model, position relative to the researcher's eye level, and proximity to the nearest window. The number of window panels blocked by blinds, the outside weather conditions, and the number of ceiling lights over the surgical suite/cubicle were also recorded. MedCalc^® version 19.2.1 (MedCalc Software Ltd^®, Ostend, Belgium, https://www.medcalc.org; 2020) was used for statistical analyses(Kruskal-Wallis test and stepwise regression analysis). The level of significance was set at P<0.05. Results: Stepwise regression analysis showed that only the monitor brand and proximity of the monitor to a window had a significant impact on the monitor's performance (P<0.05). The Kruskal-Wallis test showed significant differences (P<0.05) in monitor performance for all variables investigated, except for the weather and the clinic in which the monitors were placed. Conclusion: The vast performance variation present between computer monitors implies the need for a review of monitor selection, calibration, and viewing conditions.

• 한국방사선학회논문지
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• 제15권5호
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• pp.731-739
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• 2021

이 연구는 산업현장에서 구조물의 용접부 검사를 디지털 방사선을 이용한 비파괴검사를 효과적으로 수행할 수 있도록 디지털 방사선의 밝기 교정과 중첩 영상에 따른 신호 대 잡음 비와 기본 공간 분해능을 비교분석 하였다. 평판형 용접 시험편을 대상으로 ⁷⁵Se 방사선원을 사용하였고 촬영 전 밝기 교정과 영상 중첩을 세분화하여 총 130장의 영상을 획득하였다. 연구 결과, 밝기 교정의 수와 영상 중첩의 수가 증가할수록 신호 대 잡음 비가 향상됨을 확인하였다. 기본 공간 분해능은 촬영된 영상 모두 기준치를 만족하였다. 산란 방사선을 대비한 납 차폐를 설치 후 촬영한 영상을 비교하여 신호 대 잡음 비가 비슷함을 확인하였다. 영상 중첩이 증가할수록 신호 대 잡음 비가 증가하지만, 방사선의 노출시간이 증가하면서 작업자의 피폭 및 작업 효율에 영향을 미치기 때문에 적절한 촬영기법을 강구 한다면 좋은 상질의 디지털 방사선 영상을 획득 할 수 있을 것으로 사료된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.565-569
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• 2006

The purpose of this study was to assess the influence of the presence and impacted state of the mandibular third molars on the incidence of mandibular condyle fracture. A retrospective study was designed for patients presenting to the Department of Oral and Maxillofacial Surgery, Kyungpook National University Hospital and Tae-gu Fatima Hospital for treatment of mandibular fractures from January 2003 to January 2006. The independent variables in this study were the presence, degree of impaction of third molars, and the outcome variables were the incidence of mandibular condyle fractures. Hospital charts and panoramic radiographs were used to determine and classify these variables. The demographic data included age, sex, mechanisms of injuries and number of mandibular condyle fractures. The study sample comprised 136 mandibular condyle fractures in 105 patients. Result of this study demonstrated a statistically significant difference in ipsilateral condyle fractures and mandibular third molar absence(P=0.032) and bilateral condyle fractures without another fracture and mandibular third molar absence(P=0.028).

• 치과방사선
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• 제27권1호
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• pp.263-271
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• 1997

The authors diagnosed a 54-year-old male as central mucoepidennoid carcinoma after undergoing clinical, radiological and histopathological examinations. The characteristics were as followed : 1. Clinically, the patient complained of the painless unilateral swelling of the left mandibular molar region and had a pus discharge through the fistula. Painful nodule was palpated on the scalp of the left frontal area and it was regarded as a metastatic lesion. 2. Plain radiographs showed the ill-defined permeative radiolucent lesion. The osteolytic lesions were also detected in the cranial bone, number 9 and 11 ribs, scapula, and vertebral bodies. 3. The mandibular CT and PNS MRI showed the swelling of the left mandible and the enlargement of the several lymph nodes of 1.5 cm in size. 4. Histopathologically, many solid epidermoid type cells were mixed with mucus-secreting cells and they were arranged in duct-like structure. Most of them were epidermoid type, which indicates a high grade tumor. Mucins could be found in mucicamrine staining.

• The Korean Journal of Medicine
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• 제93권6호
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• pp.509-517
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• 2018

A small number of viable tuberculosis bacilli can reside in an individual with latent tuberculosis infection (LTBI) without obvious clinical symptoms or abnormal chest radiographs. Diagnosis and treatment of LTBI are important for tuberculosis (TB) control in public and private healthcare facilities, particularly in high-risk populations. The updated 2017 Korean guidelines for TB recommend that tuberculin skin tests, interferon-gamma release assays, or a combination of them can be used for the diagnosis of LTBI, depending on the age and immune status of the patient as well as their TB contact history. For diagnosis of LTBI, exclusion of active TB is essential, and the possibility of healed TB in those without a history of treatment for TB but at risk of its development must be considered. The treatment options for LTBI include isoniazid, rifampicin, isoniazid/rifampicin, and isoniazid/rifapentine. The benefits and risks of these agents based on the age of the patient and their hepatotoxicity must be considered when selecting the appropriate drug. Standardized diagnosis and treatment of LTBI based on the updated 2017 guidelines will contribute to the control of TB in Korea as well as to further revisions of the guidelines.

• 치과방사선
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• 제15권1호
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• pp.41-49
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• 1985

The purpose of this study was to evaluate the initial and postoperative radiographic features of the endodontic treated teeth. The author examined the radiographs which comprise 114 teeth with 155 canals of 64 persons. The following factors were considered; Age, sex, tooth location, number of root canals, postoperative periods, initial diagnosis, and radiographic findings, postoperative radiographic findings. The apical levels of the root fillings were 76.8% to apex, 19.0% underfilling, 3.9% overfilling. The following results were obtained. 1. Of the 93 teeth which revealed initial periapical rarefaction, 66 teeth (71.0%) had showed complete bone healing, 19 teeth (20.4%) decreased rarefaction, 6 teeth (6.5%) no change, 2 teeth (2.2%) increased rarefaction after 20.0 months mean healing time. 2. 21 teeth which had no initial periapical rarefaction showed no occurrence of new periapical rarefaction. 3. Of the 66 teeth completely healed, 53 teeth (80.3%) had showed reappearance of lamina dura, 64 teeth (97.0%) reappearance of periodontal ligament space after 23.4 months mean healing time.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권1호
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• pp.81-85
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• 2010

Multiple jaw cysts are one of the most constant features of the basal cell nevus syndrome. Basal cell nevus syndrome is inherited as an autosomal dominant trait with variable expressiveness. This syndrome comprises a number of abnormalities such as multiple nevoid basal cell carcinomas of the skin, skeletal abnormalities as bifid rib and fusion of vertebrae, central nervous system abnormalities as mental retardation, eye abnormalities with multiple jaw cysts. The odontogenic keratocysts in patients with this syndrome are often associated with the crowns of unerupted teeth and huge size; on radiographs they may mimic dentigerous cysts. The most important feature of the cyst is its extraordinary recurrence rate. Since recurrence may be long delayed in this lesion, follow-up of any case of odontogenic keratocyst with roentgenograms and clinical examination of basal cell carcinoma are essential for at least five years after surgery. We report the result of 7-year follow up after cyst enucleation associated with basal cell nevus syndrome with the literature of review.

• Advances in pediatric surgery
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• 제8권1호
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• pp.54-61
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• 2002

Hirschsprung's disease (HD) is usually diagnosed in the newborn period and early infancy. The common presentation of HD in newborns consists of a history of delayed passage of meconium within the first 48 hours of life. The differential diagnosis in newborns is one of the clinical challenges of this disorder. A number of medical conditions which cause functional obstruction of the intestines are easily excluded. Neonates with meconium ileus, meconium plug syndrome, distal ileal atresia and low imperforate anus often present in a manner similar to those with HD in the first few days of life. Abdominal radiographs may help to diagnose complete obstruction such as intestinal atresia. Microcolon on contrast enema can be shown in cases with total colonic aganglionosis, ileal atresia or meconium ileus. Suction rectal biopsy or frozen section biopsy at operation is essential for differential diagnosis in such cases. HD is also considered in any child who has a history of constipation regardless of age. Older children with functional constipation may have symptoms that resemble those of HD and contrast enema is usually diagnostic. However, children with other motility disorders generally referred to as chronic idiopathic intestinal pseudoobstruction present with very similar symptoms and radiographic findings. These disorders are classified according to their histologic characteristics.; visceral myopathy, visceral neuropathy, intestinal neuronal dysplasia (IND), hypoganglionosis, immature ganglia, internal sphincter achalasia. Therefore, the workup for motility disorders should include rectal biopsy not only to confirm the presence of ganglion cells but also evaluate the other pathologic conditions.

• 한국멀티미디어학회논문지
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• 제21권2호
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• pp.98-107
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• 2018

In this paper, we propose a method to classify the skeletal maturity with a small amount of hand wrist X-ray image using deep learning-based meta-learning. General deep-learning techniques require large amounts of data, but in many cases, these data sets are not available for practical application. Lack of learning data is usually solved through transfer learning using pre-trained models with large data sets. However, transfer learning performance may be degraded due to over fitting for unknown new task with small data, which results in poor generalization capability. In addition, medical images require high cost resources such as a professional manpower and mcuh time to obtain labeled data. Therefore, in this paper, we use meta-learning that can classify using only a small amount of new data by pre-trained models trained with various learning tasks. First, we train the meta-model by using a separate data set composed of various learning tasks. The network learns to classify the bone maturity using the bone maturity data composed of the radiographs of the wrist. Then, we compare the results of the classification using the conventional learning algorithm with the results of the meta learning by the same number of learning data sets.

• Imaging Science in Dentistry
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• 제48권4호
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• pp.277-281
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• 2018

Purpose: This study was performed to investigate the relationship between sleep bruxism(SB) and pulpal calcifications in young women. Materials and Methods: A total of 100 female participants between 20 and 31 years of age who were referred to our radiology clinic for a dental check-up, including 59 SB and 41 non-SB patients, were sampled for the analysis. SB was diagnosed based on the American Academy of Sleep Medicine criteria. All teeth were evaluated on digital panoramic radiographs to detect pulpal calcifications, except third molars, teeth with root canal treatment, and teeth with root resorption. Binary logistic regression analysis was used to determine the risk factors for pulpal calcifications. The Spearman correlation coefficient was applied and the Pearson chi-square test was used for categorical variables. To test intra-examiner reproducibility, Cohen kappa analysis was applied. P values <.05 were considered to indicate statistical significance. Results: A total of 2800 teeth were evaluated (1652 teeth from SB patients and 1148 from non-SB patients), and 61% of patients had at least 1 dental pulpal calcification. No statistically significant relationship was found between SB and pulpal calcifications (P>0.05). In SB patients, the total number of pulpal calcifications was 129, while in non-SB patients, it was 84. Binary logistic analysis showed that SB was not a risk factor for the presence of pulpal calcifications(odds ratio, 1.19; 95% CI, 0.52-2.69, P>.05). Conclusion: No relationship was found between SB and pulpal calcifications.