• Journal of radiological science and technology
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• v.27 no.2
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• pp.29-33
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• 2004

Until early 1980s we have lived without thinking that radon ruins our health. But, scientists knew truth that radon radioactive danger is bedeviling on indoor that we live for a long time. Specially, interest about effect that get in danger and injury for Radon and human body is inactive in our country. Recently, with awareness for Radon contamination, We inform about importance and danger of Radon in some station of the Seoul subway, indoor air of school facilities and We had interest with measure and manages. Usually, Radon gas emitted in base of building enters into indoor through building floor split windage back among radon or indoor air of radon daughter nucleus contamination is increased. Therefore, indoor radon concentration rises as there are a lot of windages between number pipe of top and bottom and base that enter crack from estrangement of the done building floor, underground to indoor. Thus, Radon enters into indoor through architecture resources water as well as, kitchen natural gas for choice etc., but more than about 85% from earth's crust emit. Danger and injury of health by Radon and Radon daughter nucleus that is indicated for cause of lung cancer incerases content of uranium of soil rises specially from inside pit of High area and a mine, cave, hermetical space with house. Safe sub-officer of radon concentration can not know and danger always exists large or small during. So, Important thing reduces danger of lung cancer by lowering concentration of Radon within house and building. Therefore, is thought that need general house Radon concentration measurement, measured Radon concentration monthly using Sintillator radon monitor. Study finding appeared high all underground market 1 year than the ground, and the winter appeared high than the summer. Specially, month that pass over 4pCi in house that United States Environmental Protection Agency advises appeared in underground, and appeared and know Radon exposure gravity by 4 months during 12 months. Therefore, Thinking that establishment and regulation of norm and preparation of reduction countermeasure about Radon are pressing feels, and inform result that measure Radon concentration.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.353-361
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• 1998

Hypothermia is widely acknowledged as fundamental component of myocardial protection during cardiac operations. Although it prolongs the period of ischemic arrest by reducing oxygen demands, hypothermia is associated with a number of major disadvantages, including its detrimental effects on enzymatic function, energy generation, and cellular integrity. The ideal way to rotect the heart is to electromechanically arrest it and perfus it with blood that is aerobic arrest. However alternative technique has been developed, based on the principles of electromechanical arrest and normothermic aerobic perfusion using continuous warm blood cardioplegia. To determine if continuous warm blood cardioplegia was beneficial in clinical practice during valvular surgery, we studied two groups of patients matched by numbers and clinical characteristics. Group included is 31 patients undergoing valvular surgery who received intermittent cold crystalloid cardioplegia. Group II included 30 patients undergoing valvular surgery who received continuous warm blood cardioplegia. Our results suggest that the heartbeat in 100% of patients treated with continuous warm blood cardioplegia converted to normal sinus rhythm spontaneously after the removal of the aortic cross-clamp, compared to only 31% of the cold cardioplegia group. After operation, pericardial closure rate was 90% area in the warm group, compared to 35% area in the cold group. 12 hours after the operation, the total amount of urine output in the warm group was greater than that in the cold group(2863${\pm}$127 ml versus 2257${\pm}$127 ml; p<0.05). After the operation, left diaphragmatic elevation developed in 55% of the cold group but in 0% of the warm group. CK-MB level in the warm group was significantly lower than cold group(2.28${\pm}$0.62 versus 9.96${\pm}$2.12; p<0.01) 1 hour after operation and CK-MB level in the warm group was significantly lower than cold group(1.80${\pm}$1.01 versus 6.00${\pm}$1.74; p<0.05) 12hours after operation. Continuous warm blood cardioplegia is at least as safe and effective as hypothermic technique in patients undergoing cardiac valvular surgery. Conceptually, this represents a new approach to the problem of maintaining myocardial preservation during cardiac operations.

• Journal of Chest Surgery
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• v.39 no.4 s.261
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• pp.281-288
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• 2006

Background: Extracardiac pericardial-flap lateral tunnel Fontan operation has theoretical advantage of growth potentiality of the extracardiac tunnels. The mid-term results of this technique and morphologic change of the lateral tunnel were studied. Material and Method: Clinical data was reviewed in 42 patients who underwent extracardiac pericardial-flap lateral tunnel Fontan operation between November 1993 and December 2004. The age was $2.8{\pm}1.5$ years and the body weight was $12.3{\pm}3.2$ kg. Extracardiac tunnel was constructed using the pedicled pericardium with the base undetached. By reviewing the follow-up cardiac angiograms, the diameter and the cross-sectional area of the lateral tunnel was compared to those of inferior vena cava. Result: There were four operative mortality cases (9.8%) and the causes of death were low cardiac output for all four cases. Postoperatively, five patients had prolonged pleural effusion longer than two weeks and one patient required a permanent pacemaker due to complete heart block. Follow-up was possible in 37 patients and the follow up duration was $3.8{\pm}2.2$ years. During that period, one patient died, of upper gastrointestional bleeding combined with heart failure and one patient died a sudden death of unknown cause. Two patients required reoperation due to subaortic stenosis and anastomosis site stenosis between inferior vena cava and lateral tunnel. In one patient, bradyarrhythmia was anew but there was no thromboembolic complication. The lateral tunnel showed growth in proportion to the size of the inferior vena cava. Conclusion: Extracardiac pericardial-flap lateral tunnel Fontan operation is relatively simple and safe. The mid-term result was favorable and the extracardiac tunnel showed potential for growth.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.17-24
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• 2007

Background: The aim of this study is to assess the clinical results of various procedures in congenital aortic stenosis. Material and Method: From August 1987 to June 2004, 53 patients of congenital aortic stenosis underwent procedures such as percutaneous balloon valvuloplasty, aortic valvuloplasty, Ross procedure, and aortic valve replacement. The mean age of initial procedures was $8.2{\pm}6.0$ years. Percutaneous balloon valvuloplasty was peformed in sixteen patients, aortic valvulopiasty in thirty two patients, Ross procedure in nineteen patients, and aortic valve replacement in fourteen patients. The mean follow duration was $80.6{\pm}60\;(0{\sim}207)$ months. Result: There was 15.1% (8/53) of early mortality and no late mortality. The six patients with critical aortic stenosis were died of left ventricular dysfunction in early series (before 1 year; 4 cases) and two patients died after the Ross procedure and aortic valve replacement respectively. After percutaneous balloon valvuloplasty, most patients needed reoperations (14/16). Thirteen patients needed reoperation, after aortic valvuloplasty. After Ross procedure, two patients needed reoperation due to aortic regurgitation caused by progressive aortic root dilatation. The actuarial survival rate after Ross procedure at 7 years was 90.5%. Conclusion: In young children before the age of one, percutaneous balloon valvuloplasty was considered as :he safe initial palliative procedure. But children over one year-old, aortic valvuloplasty were the effective procedure. Ross procedure can be preformed safely with good results.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.414-419
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• 2007

Background: Replacing the ascending aorta is a standard surgical option for treating acute type A aortic dissection. But replacing the aortic arch has recently been reported as an acceptable procedure for this disease. We compared the effects of aortic arch replacement for treating acute type A aortic dissection with the effects of ascending aortic replacement. Material and Method: From 2002 to 2006, 25 patients undewent surgical treatment for acute type A aortic dissection, 12 patients undewent ascending aortic replacement and 13 patients underwent aortic arch replacement. Among the aortic arch group, an additional distal stent-graft was inserted during the operation in 5 patients. 19 patients (11 arch replaced patients and 8 ascending aortic replaced patients) were followed up at the out patient clinic for an average of $756{\pm}373$ days. All the patients undewent CT scanning and we analyzed their distal aortic segments. Result: 4 patients who underwent ascending aortic replacement died, so the overall mortality rate was 16%. Among the 11 long term followed-up arch replacement patients, 2 patients (18.1 %) developed distal aortic dilatation and one of them underwent thoracoabdominal aortic replacement later on. However, among the 8 the ascending aortic replaced patients, 5 patients (62.5%) developed distal aortic dilatation. Conclusion: Aortic arch replacement is one of the safe options for treating acute type A aortic dissection. Aortic arch replacement for treating acute type A aortic dissection could contribute to a reduced distal aortic dilatation rate and fewer secondary aortic procedures.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.420-427
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• 2007

Background: Postpneumonectomy empyema (PPE) due to bronchopleural fistula (BPF) can be a surgical challenge for surgeons. We analyzed the follow-up outcomes after performing omentopexy and thoracoplasty for the treatment of PPE with BPF after pneumonectomy. Material and Mehod: Between December 1991 and January 2006, 9 patients underwent BPF closure using an omental pedicled flap for the treatment of PPE with BPF after pneumonectomy. There were 7 males and 2 females (mean age: $45.9{\pm}9$ years). The patients were followed up for a mean of 58 months (median: 28 months, range: $6{\sim}169$). When we performed omentopexy, the surgical procedures for empyema were thoracoplasy for 8 patients and the Clagett procedure for 1 patient. Thoracoplasty was performed for the latter patient due to recurrence of empyema, Result: For the 8 patients who were treated by omentopexy and thoracoplasty, there was 1 operation-related death due to sepsis. During follow up, 1 patient, who was treated by omentopexy and a Clagett procedure, died of acute hepatitis 40 months postoperatively. The early mortality was 11.1% (8/9). Of the 8 patients, including the 1 late death patient, successful closure of the BPF were achieved in all patients (8/9) and the empyema was cured in 7 patients (7/8). Conclusion: The BPF closure using an omental pedicled flap was an effective method for treating PPE with BPF due to 75-destroyed lung, and thoracoplasty with simultaneous omentopexy was effective and safe for removing dead space if the patient was young and in a good general condition.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.399-406
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• 2007

Background: Ischemia-reperfusion injury related to unsuccessful myocardial protection affects postoperative ventricular function and mortality during open-heart surgery. We prospectively compared the effects of administration of histidine-tryptophan-ketoglutarate (HTK) solution and cold blood cardioplegia (CBC) on myocardial protection and clinical outcome in patients undergoing mitral valve surgery. Material and Method: Seventy patients with mitral regurgitation (MR) undergoing mitral valve surgery were randomly divided into the HTK group (n=31) and the CBC group (n=31 ): eight patients were excluded. Perioperative hemodynamics, cardiac medications, pacing, postoperative outcomes and complications were recorded during the hospital stay. All patients received follow-up for at least 6 months postoperatively for morbidity and mortality. Resuか: There were no significant differences in the hemodynamics between the groups during the study period, except for the mean pulmonary artery pressure (MPAP), PCWP and CVP that were lower in the HTK group at 15 min after weaning of CBP. There were no differences for inotropic support and pacing during the 12 hrs postoperatively between the groups. CK-MB values on day 1 and day 2 were $77{\pm}54$ and $41{\pm}23$ for the HTK group and $70{\pm}69$ and $44{\pm}34$ for the CBC group, respectively (p=NS). Postoperative clinical outcomes were similar in both groups for at least 6 months during the follow-up period. Conclusion: These results suggest that the use of HTK solution is as safe as cold blood cardioplegia in terms of myocardial protection.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.133-144
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• 2004

A model and a measure which can evaluate the risk of rear end collision are developed. Most traffic accidents involve multiple causes such as the human factor, the vehicle factor, and the highway element at any given time. Thus, these factors should be considered in analyzing the risk of an accident and in developing safety models. Although most risky situations and accidents on the roads result from the poor response of a driver to various stimuli, many researchers have modeled the risk or accident by analyzing only the stimuli without considering the response of a driver. Hence, the reliabilities of those models turned out to be low. Thus in developing the model behaviors of a driver, such as reaction time and deceleration rate, are considered. In the past, most studies tried to analyze the relationships between a risk and an accident directly but they, due to the difficulty of finding out the directional relationships between these factors, developed a model by considering these factors, developed a model by considering indirect factors such as volume, speed, etc. However, if the relationships between risk and accidents are looked into in detail, it can be seen that they are linked by the behaviors of a driver, and depending on drivers the risk as it is on the road-vehicle system may be ignored or call drivers' attention. Therefore, an accident depends on how a driver handles risk, so that the more related risk to and accident occurrence is not the risk itself but the risk responded by a driver. Thus, in this study, the behaviors of a driver are considered in the model and to reflect these behaviors three concepts related to accidents are introduced. And safe stopping distance and accident occurrence probability were used for better understanding and for more reliable modeling of the risk. The index which can represent the risk is also developed based on measures used in evaluating noise level, and for the risk comparison between various situations, the equivalent risk level, considering the intensity and duration time, is developed by means of the weighted average. Validation is performed with field surveys on the expressway of Seoul, and the test vehicle was made to collect the traffic flow data, such as deceleration rate, speed and spacing. Based on this data, the risk by section, lane and traffic flow conditions are evaluated and compared with the accident data and traffic conditions. The evaluated risk level corresponds closely to the patterns of actual traffic conditions and counts of accident. The model and the method developed in this study can be applied to various fields, such as safety test of traffic flow, establishment of operation & management strategy for reliable traffic flow, and the safety test for the control algorithm in the advanced safety vehicles and many others.

• Radiation Oncology Journal
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• v.23 no.2
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• pp.92-97
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• 2005

Purpose : Reports on the outcome of curative radiotherapy for the primary hepatocellular carcinoma (HCC) are rarely encountered in the literature. in this study, we report our experience of a clinical trial where fractionated stereotactic radiotherapy (SRT) was used in treating a primary HCC. Materials and Methods : A retrospective analysis was peformed on 20 patients who had been histologically diagnosed as HCC and treated by fractionated SRT. The long diameter of tumor measured by CT was $2\~6.5$ cm (average: 3.8 cm). A single dose of radiation used in fractionated SRT was S or 10 Gy: each dose was prescribed based on the planning target volume and normalized to $85\~99\%$ isocenter dose. Patients were treated $3\~5$ times per week for 2 weeks, with each receiving a total dose of 50 Gy (the median dose: 50 Gy). The follow up period was $\~55$ months (the median follow up period: 23 months). Results : The response rate was $50\%$ (12 patients), with 4 patients showing complete response ($20%$), 8 patients showing partial response ($40\%$), and 8 patients showing stable disease ($40\%$). The 1-year and 2-year survival rates were $70.0\%$ and $43.1\%$, respectively, and the median survival time was 20 months. The 1-year and 2-year disease free survival rates were $65\%$ and $32.5\%$, respectively, and the median disease-free survival rate was 19 months. Some acute complications of the treatment were noted as follows: dyspepsia in 12 patients ($60\%$), nausea/emesis in 8 patients ($40\%$), and transient liver function impairment in 6 patients ($30\%$). However, there was no treatment related death. Conclusion : The study indicates that fractionated SRT is a relatively safe and effective method for treating primary HCC. Thus, fractionated SRT may be suggested as a local treatment for HCC of small lesion and containing a single lesion, when the patients are inoperable or operation is refused by the patients. We thought that fractionated SRT is a challenging treatment modality for the HCC.

• Water for future
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• v.5 no.1
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• pp.27-36
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• 1972

This thesis is the study of the rainfall probability depth in the major areas of Korea, such as Seoul, Pusan and Taegu. The purpose of the paper is to analyze the rainfall in connection with the safe planning of the hydraulic structures and with the project life. The methodology used in this paper is the statistical treatment of the rainfall data in the above three areas. The scheme of the paper is the following. 1. The complementation of the rainfall data We tried to select the maximm values among the values gained by the three methods: Fourier Series Method, Trend Diagram Method and Mean Value Method. By the selection of the maximum values we tried to complement the rainfall data lacking in order to prevent calamities. 2. The statistical treatment of the data The data are ordered by the small numbers, transformed into log, $\sqrt{}, \sqrt[3]{}, \sqrt[4], and$\sqrt[5], and calculated their statistical values through the electronic computer. 3. The examination of the distribution types and the determination of the optimum distibution types By the $x^2-Test$ the distribution types of rainfall data are examined, and rejected some part of the data in order to seek the normal rainfall distribution types. In this way, the optimum distribution types are determined. 4. The computation of rainfall probability depth in the safety project life We tried to study the interrelation between the return period and the safety project life, and to present the rainfall probability depth of the safety project life. In conclusion we set up the optimum distribution types of the rainfall depths, formulated the optimum distributions, and presented the chart of the rainfall probability depth about the factor of safety and the project life.ct life.