• Journal of Chest Surgery
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• 제31권3호
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• pp.271-278
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• 1998

In order to access the value of computed tomography in mediastinal LN staging of NSCLCa, 581 LN stations of 77 patients were selected from 552 patients who were diagnosed as Lung Ca and operated in Seoul National University Hospital from 1992 to 1995. The selection criteria were as follows ; the patients 1) whose preoperative chest CTs were available; 2) underwent curative resection (lobectomy or more) with complete lymph node dissection; 3) whose final pathologic diagnosis were proven to be non-small cell lung cancer. We adopted Receiver Operating Characteristic curve method to determine a proper size criterion for diagnosing malignant mediastinal adenopathy. From curve analysis, we decided the size criterion of lymph node to 1 cm in their short axis. Using this size criterion, it's sensitivity was 43.9%, specificity was 87.4%, and accuracy was 83.1%. Eventhough we couldn't determine the precise size criterion for the adenoca, it seemed that shorter than 1 cm size criterion should be applied in that particular cell type. Lymph node stations associated with the tuberculosis or bronchiectasis tend to be overestimated in nodal staging and have relatively high false positive rate. The low sensitivity of CT scan suggest that radical and complete dissection or precise mediastinal lymph node evaluation through the surgical approach is mandatory.

• Proceedings of the Korean Society of Radiological Science
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• 대한방사선과학회 1994년도 추계학술대회
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• pp.111.2-112
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• 1994

• Journal of the Korean Magnetics Society
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• 제24권6호
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• pp.191-196
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• 2014

The purpose of this study is to evaluate the reproducibility and usefulness of an image through the fusion of the computed tomography image and the magnetic resonance image by using a self-produced phantom when planning the treatment, and also to compare and analyze the target dose on the acquired image. The size of small hole and the reproducibility of capacity existed in the phantom on the image of the phantom obtained by the computed tomography and the magnetic resonance image of the phantom scanning with different intensity of magnetic field are compared, and the change of dose in the random target is compared and analyzed.

• Korean Journal of Biological Psychiatry
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• 제2권2호
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• pp.169-176
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• 1995

두부 외상은 많은 발생율과 사망율을 차지하고 있으며, 건강한 생활을 위해 큰 관심을 갖게 되었다. 신경방사선영상은 외상성 뇌손상 환자들의 진단과 치료에 필수적인 방법이다. 뇌손상의 기본 기전, 병리, 그리고 영상 소견을 이해 하는 것은 매우 중요하다. 1970년대에 Glasgow coma scale의 형상과 전산화단층촬영(CT)의 발달은 임상의사들이 두부외상에 대한 평가와 환자들의 경과를 예상하는데 극적인 변화를 주었다. 최근 자기공명영상(MRI)의 발달로 외상성 뇌손상의 형태를 더욱 이해 하게 되었고, 두부 외상의 발견율이 높아지게 되었다.

• 전기의세계
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• 제48권8호
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• pp.33-39
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• 1999

• Journal of radiological science and technology
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• 제34권3호
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• pp.215-219
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• 2011

Monte Carlo simulation was performed to investigate optimal system of proton computed tomography and to avoid the errors by using data from X ray computed tomography in proton therapy. The informations from two DSSDs to measure position and LYSO scintillation detector to measure the residual energy of proton particle in GEANT4 were used for reconstruction computed tomography.

• Journal of Yeungnam Medical Science
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• 제13권1호
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• pp.134-140
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• 1996

Recently many studies have shown the usefulness of computed tomogram in diagnosing abdominal mass when clinical and conventional radiologic examinations fail to reveal the nature of abdominal mass or the cause of abdominal distension. To evaluate the usefulness of CT in diagnosing neuroblastoma, we retrospectively analyzed computed tomographic findings of 16 neuroblastoma patients, who pathologically proved in Yeungnam University Hospital from 1986 to 1995. The age range of the patients studied were from 8months to 18years. The most frequent sith of origin was adrenal gland and the next was retroperitioneum. The presenting symptoms were palpable mass, abdominal distension, and abdominal pain. The viewpoints of this analysis were turnoral calcifications, midline cross, shape, margin, internal structure, contrast enhancement patterns, major vessel involvement, and lymph node involvement. Characteristic CT findings were as follows: Fine dense curvillinear calcification within the tumor(56%), midline cross(50%), lobulation(75%), well-circumscribed margin(56%), cystic degeneration(56%), heterogeneous contrast enhancement(69%). encasement of major vessels such as aorta, IVC and celiac trunk(50%), and paraaortic lymphadenopathy(87%). We conclude that these CT findings were very common and could be helpful in diagnosting and differentiation neuroblastoma in infant and children.

• Journal of the Korean Society of Radiology
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• 제9권6호
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• pp.403-408
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• 2015

Hard X-ray has been widely used in medical and industrial fields because it can be applied to observe the inside of a sample. Computed tomography provides sectional images of the sample through the reconstruction of the projection images. The quality of sectional images strongly depends on that of projection images. Ring artifact appeared on the seconal image can be made by the abnormal pixels of the detector used. In this study, we examine the ring artifact ratio in the circle phantom as a function of detection error of the detector used in computed tomography. The ring artifact increased with the increment of detection error under parallel and fan beam geometries and strongly increased near the center of rotation. The corrections, dead pixel and flat field corrections, for the images taken with the detector are required before the image reconstruction process to reduce the ring artifact in the computed tomography.

• Journal of the Korean Society of Radiology
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• 제81권2호
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• pp.250-271
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• 2020

Assessment of myocardial ischemia in patients with stable angina is important in deciding whether to treat coronary artery disease and in predicting clinical outcome. The fractional flow reserve is a standard reference for the diagnosis of myocardial ischemia, but this procedure has limitations because of its invasiveness. Coronary computed tomography angiography (CCTA) is now an established tool in the anatomic diagnosis of coronary artery disease; however, there are limits to the diagnosis of hemodynamically important stenosis that causes myocardial ischemia. In order to address this problem, studies using quantification of coronary atherosclerotic plaques, myocardial perfusion, and noninvasive calculation of fractional flow reserve based on CCTA have been actively conducted and recognized for their diagnostic value. In this review, several imaging techniques of CCTA used to assess myocardial ischemia are described.

• Journal of Gastric Cancer
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• 제9권4호
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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.