• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.54-69
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• 2022

Early detection of potential asymptomatic coronary artery disease is very important, as patients with sudden cardiac death often do not show symptoms such as chest pain or motor dyspnea. Coronary CT angiography (CCTA) has long been unjustified as a screening tool for asymptomatic patients because of the risks posed by radiation exposure. However, there are still various opinions regarding the usefulness of CCTA for screening for coronary artery disease (CAD) in asymptomatic healthy individuals or patients. This review investigated the usefulness of coronary artery calcium score and CCTA as screening tests for CAD in asymptomatic healthy individuals or patients through various literature reviews. With the development of CT technology, recent studies have been conducted in asymptomatic CAD patients with a reduced radiation dose of less than 1 mSv. A total of 2.6% of asymptomatic subjects on CCTA found significant CAD over 70%, and it was concluded that screening CCTA for CAD showed prognostic power in predicting the future occurrence of CAD in asymptomatic people. However, after the completion of the current NIH SCOT-HEART 2 study, it may be possible to determine whether CCTA is appropriate as a screening tool for CAD in asymptomatic healthy individuals.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.109-115
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• 2015

In case of a CT examinations, there is a difference in the distribution of radiation dose from that of general X-ray equipments, and it has been known to cause a great radiation exposure during the examinations. However, owing to its high reliability on the accuracy of a examinations result, its use has increased continuously. In consideration of such a circumstance, the CT equipment, radiation dose during CT examinations, diagnostic reference level, and solutions to reduce radiation dose were mentioned on the basis of previously reported data.

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.184-191
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• 2007

Our objective was to develop and evaluate a non-invasive device for rigid immobilization and surface disease non-contact of the table in the lower extremity during CT angiography. The immobilization device consists of two components. The patient's lower limb device stabilizing elements made of polyethylene resin soft materials, and pelvis parts foam pad is used for non-contact surface. In a Prospective study the lower extremity device was used in patients who underwent a CT angiography of the lower limb. Immobilization with our device was well tolerated by all patients. The quality of the resulting images in the popliteal and infrapopliteal region was rated by five-point scale. The rigid immobilization resulted in a complete absence of motion artifacts. The new device is an effective, well tolerated and easily used immobilization that is suitable of use in 3D lower extremity CT angiography.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.495-502
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• 2019

A typical cerebrovascular disease among cerebrovascular diseases is vascular diseases such as cerebral infarction, cerebral hemorrhage, cerebral aneurysm, cerebrovascular stenosis. If the disease occurs and causes cerebral damage, it may be difficult to recover completely. So that, Must continue to perform health care through examination early. In particular, Because most cerebrovascular disease examining use radiation equipment and Thus this study was to find out how to select about the optimal examining method and X-ray dose decrease method among different examining method though comparison and analysis for the entrance surface dose (ESD) on cerebrovascular examining with Trance Femoral Cerebral angiography (TFCA) and Cerebral Computed Tomographic Angiography (CCTA). Also, want to find out how to select about the optimal examining method for worried patient that contrast medium side effect though measuring and evaluating for contrast usage. Data were collected from 70 patients (43 males and 27 females) who underwent CCTA at Yeosoo region hospital from June 2018 to December 2018 and 61 patients (34 males and 27 females) who underwent TFCA at Pyeongtaek region hospital from June 2018 to November 2018. ESD analysis method collected retrospective data though M-view and PACS PLUS program, Used contrast usage measuring method did reality measuring method. In the analysis using SPSS, the ESD of TFCA was $245.74{\pm}71.91$, which was $32.05{\pm}7.74$ lower than the dose of $277.79{\pm}79.65$ of CCTA ESD, and statistically significant at t = 3.249, p = 0.017 (p<0.05). As a result of the comparison of the total amount of contrast agent, the mean contrast agent used in TFCA was $55.05{\pm}17.68ml$, which was about 14.95 smaller than the amount of contrast agent used in CCTA, and statistically significant t = -4.548, p<0.001. In conclusion, the ESD of TFCA was statistically significantly lower than that of CCTA, and also the used contrast usage was significantly tiny than that of CCTA. Therefore, Select the method to increase the utilization of TFCA for cerebral disease examining, we can consider X-ray dose decrease method at the same time as to decrease side effect of contrast medium.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.226-232
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• 2009

Background: Blunt chest trauma accounts for 90% of all chest traumas in Europe and the United States and this causes 20% of all trauma-related deaths. The major cause of morbidity and mortality after blunt chest trauma is undetected injuries. For this reason, chest computerized tomography has gained popularity for the evaluation of trauma, but it is expensive and it exposes patients to radiation. This study identified the clinical features associated with the diagnosic information obtained on a CT chest scan, as compared with a standard chest X-ray, for patients who sustained blunt trauma to the chest. This study also evaluated the role of a routine computed tomographic (CT) scan for these patients. The patients who had chest computed tomography done after the initial chest x-ray were analyzed separately for the presence of occult injuries. Material and Method: We studied 100 consecutive patients from November 2006 to July 2007: 74 patients after motor vehicle crashes and 26 patients after a fall from a height >2m. Simultaneous with the initial clinical evaluation, an anteroposterior chest radiograph and a helical chest CT scan were obtained for all the patients. The data extracted from the medical record included the vital signs, the interventions and the type and severity of injury (RTS). Result: Among the 100 cases, 79 patients showed at least more than one pathologic sign on their chest radiograph, and 21 patients had a normal chest radiograph. For 17 of the patients who had a normal chest X ray, the CT scan showed multiple injuries, which were pneumothorax, hemothorax, lung contusion, sternal fracture etc. This represents that a CT scan is statistically superior to a chest radiograph to diagnose the pathologic signs. But on the other hand, as for treatment, only 31 patients were diagnosed by CT scan and they were treated with chest tube insertion ect. 42 patients needed ony conservative management without invasive thoracosurgical treatment such as chest tube insertion or open thoracotomy. 27 patients were treated based on the diagnosis made by the chest radiograph and physical examination. Conclusion: Chest computerized tomography was significantly more effective than routine chest X-ray for detecting lung contusion, pneumothorax and mediastinal hematoma, as well as fractured ribs, scapula and, sternum. Although the occult findings increased, the number of patients who needed treatment was small. Therefore, we suggest making selective use of a CT scan to avoid its overuse in ERs.

• Journal of Veterinary Clinics
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• v.27 no.5
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• pp.579-583
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• 2010

An 18-month-old intact male Pomeranian dog was presented because of traumatic head injury from a fall. Based on physical and neurological examination, brain injury was suspected. On plain skull radiographs, bony fragment following fracture was identified in the region of the right occipital bone. On computed tomography (CT) images, there were specific findings associated with an intracranial hemorrhage. The patient expired few hours after diagnosis, and performed necropsy. On gross findings, intracerebral hemorrhage and edema was detected and those were consistent with CT images. This report describes the clinical findings, CT imaging characteristics, necropsy findings, and histopathologic features of severe traumatic brain injury in a dog.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.459-464
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• 2019

In order to minimize the radiation exposure dose of the thyroid site at dental cone-beam computer tomography, a protector using a Bolus was prepared, and the radiation shielding effect and the appropriateness of the image were evaluated. Using a dental cone-beam computed tomography (CBCT), a glass dosimeter was attached to the left and right sides of the thyroid for a dental radiation phantom, and the radiation dose was measured. The absorbed dose for each shield was measured by another method to 10 mm, 20 mm, and 30 mm-thickness, respectively. Eight evaluators evaluated whether or not the medical image is appropriate. When using a 30 mm Bolus shield at the left thyroid site, the resulting value is reduced by an average of $342.67{\mu}Gy$ by 20.7% from the average value of $431.22{\mu}Gy$ measured without using a Bolus shield, the right thyroid site In the case of using 30 mm Bolus shield, it showed a dose reduction effect of 21.9% with an average of $424.56{\mu}Gy$. The adequacy of the medical image was judged to be usable by both evaluators. In conclusion, the dental cone-beam computerized tomography can be used as a useful shielding material because it has a radiation shielding effect and it is possible to treat the diagnosis of the bolus protector in the thyroid without any obstruction shade in order to minimize the radiation dose.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.195-196
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• 2011

1996년 이후부터 전산화단층촬영 검사가 건강보험급여대상이 되면서 이용률과 보급률이 더욱 증가되고 있으며 검사범위의 확대, 검사시간의 단축, 반복검사의 용이성, 이용의 편리성, 결과의 신뢰성, 장치의 구조적인 요소 및 검사 시행 횟수의 증가 등으로 검사량이 증가되고 있는 실정이다. CT 검사 건수의 증가요인으로 새로운 CT장비의 개발과 더불어 급격한 장비도입 증가 추세가 있으므로 이에 본 연구에서는 의료기관 종별 및 시기별 CT 장치 보유현황과 검사료간의 관계를 파악하였다. CT 장비는 병원급은 증가하고 있는 추세이나 의원급은 감소하고 있는 것으로 나타났다. CT진료비 청구는 80%이상이 종합전문요양기관과 종합병원에서 청구하는 것으로 나타났다. 이에 본 연구에서는 고가의료영상 진단 장비인 CT의 세대별 발달장비 도입 시기에 따른 우리나라 CT의 현황을 조사 분석하여 제시하여 고가의료장비 수급의 정책수립의 계기 및 기여하고자 한다.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.177-185
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• 2009

Purpose: Preoperative clinical staging of gastric cancer is very important for determining the treatment plans and predicting the prognosis. The previous reports regarding the accuracy of computed tomography or endoscopic ultrasound for the preoperative staging of gastric cancer have shown various outcomes. We analyzed the diagnostic performance of CT and EUS, which are important staging tools for the staging of TN gastric cancer. Materials and Methods: We retrospectively analyzed 1,174 patients who underwent gastrectomy for gastric cancer at Seoul National University Bundang Hostpital from May, 2003 to December, 2007. We derived the Kappa value to examine the agreement of the preoperative staging obtained from CT and EUS with the pathological staging. Results: The mean age of the 1,174 patients was $59.31{\pm}11.98$ years. Six hundred thirty seven patients had early gastric cancer and 536 had advanced gastric cancer. The diagnostic performance between CT and EUS for the T staging showed no significant difference between CT and EUS for the kappa values. The kappa values showed moderate agreement at 0.4039 (P=0.021) and 0.4201 (P=0.026), respectively. This suggests that there is no difference between the two examinations for the overall T staging. Analysis of the discrimination of mucosal and submucosal lesions with EUS showed an accuracy of 58.92% and a Kappa value of 0.206 (P<0.001), suggesting fair agreement and a lower diagnostic performance than expected. To differentiate lesions with stages higher than or equal to T2 or T3 from the lesion with stages lower than T2 or T3, respectively, adoption of the higher stage from the CT staging or the EUS staging showed a larger AUC of 0.84 than that from either stage alone. The CT-derived node stage had the higher diagnostic performance (68.55%) than that of the EUS-derived node stage (60.82%) for the node staging. Conclusion: The CT-derived stage and EUS-derived stage showed comparable results for determining the T stage of gastric cancer. Yet the higher stage of the two stages from CT and EUS most accurately discriminated between those lesions with stages higher than T2 and those lesions with stages lower than T2.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.1
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• pp.1-8
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• 2008

The object of this study is to develop the examination technique for measuring the O-ring deformation behavior under the pressure and the squeezed condition simultaneously. The O-ring deformation measuring device in which two grooves were dug to insert the two O-rings was manufactured to be not deformed under the high pressure and the 1 mm and 0.1 mm gap were designed to measure the extrusion lengths under the internal pressure. The beam hardening correction, the histogram analysis and the dead zone correction were executed to exactly measure the shape of O-ring deformation and the lengths of the O-ring deformation were measured by the LSF and the ERF. The computed tomography applied the pressure of 0, 1.378, 4.902, 9.804, 15.692 MPa at 22.3% squeezed condition and the expanded diameter, contact length and extrusion depth were measured in each pressure. The shape of O-ring deformation was evaluated by the FEM to verify the results of measuring by the computed tomography and the area of O-ring was mutually compared to the area measured by the computed tomography.