• Progress in Medical Physics
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• v.10 no.3
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• pp.151-157
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• 1999

The GafChromic film was used for the dosimetry of a balloon angio catheter filled with the radioisotope HO-166 for endovascular irradiation. The balloon angio catheter was 2 cm long and 3 mm in diameter when inflated. The isotope, Ho-166, was produced by the neutron bombardment using the research reactor in Korea Atomic Energy Research Insititute. Co-60 teletherapy beam was used for making H-D curve for the Gaf-Chromic film. The film dosimetry was measured with a videodensitometer. The radial dose distribution indicated that the absorbed dose dropped to about 20% of the surface dose at the 1 mm away from the balloon surface and at 5 mm position the dose decreased to below 1% of the surface dose. The result also shows that with the specific activity of Ho-l66, 250 mCi/ml it takes 230 seconds to deliver 1200 cGy to the region where is 1mm away from the balloon surface. The concentric isodose curves were also presented. The Ho-166 is an another alternative for endovascualr irradiation to prevent restenosis after PTCA (Percutaneous Trans Coronary Angioplasty)

• Journal of Chest Surgery
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• v.36 no.1
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• pp.55-58
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• 2003

Although postanastomosis of esophageal reconstruction is rare but it is a very unwelcome complication. Previously, the problem was solved by balloon dilatation, reoperation, and feeding jejunostomy. However, balloon dilatation is not effective because of high recurrence rate, reoperation is difficult due to its operative approachableness and also jejunostomy is inconvenient for patients. Therefore, we inserted esophageal stent as a method of relieving postanastomosis stenosis, From Jan, 2001 to Dec, 2001, there were three patients with postanastomosis stenosis, who received esophageal stent insertion, one had case is benign esophageal stenosis, two had esophageal carcinoma. We followed up them over 12 months after inserting the stent, Dysphagia was improved, so we report that the clinical performance was satisfactory

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.180-188
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• 2014

It is very important accurate diagnosis and quick treatment in cerebrovascular disease, i.e. stenosis or occlusion that could be caused by risk factors such as poor dietary habits, insufficient exercise, and obesity. Time-of-flight magnetic resonance angiography (TOF-MRA), it is well known as diagnostic method without using contrast agent for cerebrovascular disease, is the most representative and reliable technique. Nevertheless, it still has measurement errors (also known as overestimation) for length of stenosis and area of occlusion in celebral infarction that is built by accumulation and rupture of plaques generated by hemodynamic turbulence. The purpose of this study is to show clinical trial feasibility for 3D-SPACE T2, which is improved by using signal attenuation effects of fluid velocity, in diagnosis of cerebrovascular disease. To model angiostenosis, strictures of different proportions (40%, 50%, 60%, and 70%) and virtual blood stream (normal saline) of different velocities (0.19 ml/sec, 1.5 ml/sec, 2.1 ml/sec, and 2.6 ml/sec) by using dialysis were made. Cross-examinations were performed for 3D-SPACE T2 and TOF-MRA (16 times each). The accuracy of measurement for length of stenosis was compared in all experimental conditions. 3D-SPACE 2T has superiority in terms of accuracy for measurements of the length of stenosis, compared with TOF-MRA. Also, it is robust in fast blood stream and large stenosis than TOF-MRA. 3D-SPACE 2T will be promising technique to increase diagnosis accuracy in narrow complex lesions as like two cerebral small vessels with stenosis, created by hemodynamic turbulence.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.433-437
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• 1999

Background: Left main coronary artery (LMCA) angioplasty is another option in the surgical treatment for LMCA disease because of its advantages over the conventional coronary artery bypass grafting (CABG). Material and Method: Between July 1994 and December 1997, 15 patients underwent left main coronary angioplasty for the stenoses of LMCA. There were 8 males and 7 females with the mean age of 53.3${\pm}$8.8 years. The locations of the LMCA stenoses were proximal one-third of the LMCA in 9, middle one-third in 1, distal one-third in 3, and the whole length of the LMCA in 2 cases. Nine patients had peripheral coronary lesions in addition to the LMCA stenosis. The LMCA was approached anteriorly with or without transsection of the main pulmonary artery. The angioplasty was performed with onlay patch widening using an autologous pericardium (14 cases) or saphenous vein (1 case). Additional graftings were required in 9 cases, and both LMCA angioplasty and right coronary ostial angioplasty were done in 1 case. Result: There was no operative mortality. One case needed redo CABG due to the stenosis of the angioplasty site which developed 4 months postoperatively. Coronary angiography was performed in 8 cases one year postoperatively, and revealed good patency of the angioplasty site except for one who showed 50% stenosis at the angioplasty site. No patient complained of angina with a mean follow up of 23${\pm}$11 months. Conclusion: Surgical angioplasty of the LMCA stenosis can be performed in selected cases with safety and good mid-term results.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.77-81
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• 2011

It is a well-known clinical fact that contrast-enhanced magnetic resonance angiography exaggerates vertebral arterial ostial stenosis and sometimes shows pseudostenosis. Considering the clinical significance of a lesion in the posterior circulation ischemia, the importance of an accurate imaging diagnosis of ostial stenosis should not be underestimated. We were able to differentiate pseudo stenosis of the ostium from true stenosis using thin-slab maximum-intensity-projection(MIP) images which are thought to be helpful for minimizing standard full thickness MIP images.

• Journal of Chest Surgery
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• v.40 no.8
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• pp.546-551
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• 2007

Background: The radial artery is gaining widespread acceptance as complementary arterial conduits for surgical myocardial revascularization, but there have been limited reports about its angiographic patency compared with that of internal thoracic artery or saphenous vein. We tried to evaluate angiographic patency of radial artery graft and to compare that of radial artery and other gratis with retrospective manner. Material and Method: From January 2001 to Jure 2006, totally 132 patients (male 92, female 40) who underwent coronary artery bypass graft using radial artery were re-admitted to our hospital for follow up angiographic examination. Mean age was 58.2+8.87 and mean follow up duration was 32 month ($2{\sim}110$ month). Off pump and on pump bypass surgery were performed 74 and 58 patients respectively. Along with radial artery, left internal thoracic arteries were used in 57 cases, concomitant left internal thoracic artery and saphenous veins were used in 47 cases and bilateral internal thoracic arteries were used in 20 cases. Result: Totally 412 distal anastomosis were performed and 376 anastomosis remained patent (91.2%). Left internal thoracic artery showed the most excellent patency in all of the conduits (98.5%). Radial artery graft patency was 90.8% (169/186). There was no statistical difference of the patency by conduit between on-pump and off-pump group. But radial artery showed more higher patency rate (98/110, 89%) in the severe stenotic lesion that preoperatively revealed more than 90% stenosis than in the lesser severe (<90%) stenotic lesion (60/76, 78%)(p < 0.005). Radial artery conduit represented the worst result when it was grafted in the right coronary system. But when it was positioned in the left heart especially diagonal or obtuse marginal area, patency was comparable with left internal thoracic artery. Conclusion: Radial artery graft showed good midterm patency when it was used in the severe stenotic lesion more than 90% and left coronary system. But great notice should be taken when it is grafted in the right coronary system or less severe stenotic lesion.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.839-841
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• 2002

Generally, patients who have airway compression with severe kyphoscoliosis can be improved through surgery for the thoracolumbar deformity. However, abnormal thoracic configuration due to severe kyphoscoliosis can cause respiratory distress secondary to severe compression of central airway in uncorrectable case. We tried to elevate the chest wall and obtained relatively good result in case of airway compression with abnormal thoracic configuration which was difficult to correct.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.631-634
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• 2017

뇌혈관은 평상시 뇌조직의 필요량보다 더 많은 혈류를 수송할 능력을 가지고 있는데 이를 뇌혈관 혈류예비력이라 한다. 뇌혈관이 특정한 요인에 의해 협착이 생기면 뇌관류압이 감소하는데 이를 보상하기 위해 뇌세동맥의 내경을 확장시켜 뇌혈류를 유지하도록 하는 것이다. 따라서 예비력이 낮은 사람일 경우 협착으로 인해 혈관 내경이 좁아져 있다면 운동이나 스트레스 상황에서 뇌졸증 내지 뇌허혈의 위험이 증가된다. 따라서 본 연구팀은 컴퓨터 시뮬레이션을 통해 뇌혈관 협착으로 인한 예비능 감소를 예측하였다. 이를 위해 환자의 MRA 영상 이미지를 영역화하여 3차원 격자를 생성하였으며 생성된 환자 맞춤 모델을 대상으로 전산유체해석을 진행하였다. 그리고 가상 협착을 모델에 적용하여 뇌혈관 협착률과 예비능의 관계를 분석했다.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1987.05a
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• pp.13.1-13
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• 1987

저자들은 1984년 12월 17일부터 1987년 2월 26일까지 경희대학교 의과대학 부속병원 이비인후과 및 흉부외과에서 경험한 9례의 기관협착증환자를 대상으로 임상적 고찰을 하여 다음과 같은 결과를 얻었다. 1) 연령 및 성별분포는 여자 3례, 남자 6례이었고, 10세이하 3례, 10대 2례, 20대 2례, 40대 이상이 2례 이었다. 2) 원인은 지속적 기관내삽입관에 의한 경우가 4례이었고 1례는 선천성 혈관기형인 double aortic arch에 의해 기관이 눌리어 기도협착증상이 있었던 경우이었다. 상기관절개술에 의한 경우가 2례, 경부외상 1례, 기관내 종양 2례이었다. 3) 협착부위의 길이는 1.5cm에서 2cm까지가 4례로 가장 많았고 3cm이내가 2례, 4cm이내 1례, 6cm이내 1례이었다. 4) 치료는 보존적인 방법으로 내시경하에서 육아조직 및 반흔조직을 laser를 이용하여 제거한 후 silastic stent 혹은 Montgomery T-tube 삽입후 4주에서 6주후 제거하여 치료한 경우가 2례이었고 협착부위절제 및 단단문합술을 시행한 경우가 6례이었다. 1례에서는 aortic arch division을 시행하였다. 5) 예후는 9례중 단단문합술을 시행한 6례 그리고 보존적 방법으로 laser를 이용한 육아조직의 제거 및 지지물삽입을 시행한 3례에서 모두 현재까지 재발은 보이지 않고 있다. 6) 기관협착의 길이가 1.5cm에서 4cm까지의 경우에는 supralaryngeal release procedure없이 단단문합술을 시행하였고 협착길이가 6cm인 1례에서는 supralaryngeal release를 하여 tension없이 문합술을 시행할 수 있었다.

• Tribology and Lubricants
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• v.14 no.1
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• pp.94-98
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• 1998

혈관내피세포는 혈관의 내벽에 단일 층을 구성하고 있는 상피세포로 동맥경화나 혈관협착의 원인에 매우 중요한 역할을 하는 것으로 알려져 있다. 그리고, 모든 혈관 질환의 발생장소가 혈관이 나뉘는 분지부에 집중되고 있어, 혈류역학과 혈관질환 간에 상호연관성이 있음을 짐작할 수 있다. 특히, 최근에 와서 혈관내피세포가 혈액유동에 의해 발생하는 전단응력을 인지하여 혈관의 제반 생리적 반응을 조절한다는 연구결과가 속속 발표되고 있어, 혈관질환의 극복을 위한 연구 개발에 혈관내피세포에 대한 이해의 중요성이 증대되고 있다. 이에 본 연구에서는 혈관내피세포에 혈류와 같은 크기의 전단응력을 부가하여 세포의 생리적 반응을 고찰할 수 있는 평판형 층류발생장치를 설계, 제작하였다. 설계된 평판형 층류발생장치는 유동환경 하에서의 혈관내피세포의 동적반응을 고찰 할 수 있도록 유동액의 온도, 산도, 전단응력의 크기를 조절할 수 있도록 설계하였으며, 제작된 실험장치를 이용하여 전단응력에 의한 혈관내피세포의 형태변화를 고찰하였다. 개발된 층류발생장치는 혈관내피세포의 연구 뿐 아니라, 백혈구의 점착, 암세포의 전이등에도 다양하게 활용이 가능하다.