• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.123-135
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• 2012

Purpose: It is essential to minimize the movement of tumor due to respiratory movement at the time of respiration controlled radiotherapy of non-small cell lung cancer patient. Accordingly, this Study aims to evaluate the usefulness of restricted respiratory period by comparing and analyzing the treatment plans that apply free and restricted respiration period respectively. Materials and Methods: After having conducted training on 9 non-small cell lung cancer patients (tumor n=10) from April to December 2011 by using 'signal monitored-breathing (guided- breathing)' method for the 'free respiratory period' measured on the basis of the regular respiratory period of the patents and 'restricted respiratory period' that was intentionally reduced, total of 10 CT images for each of the respiration phases were acquired by carrying out 4D CT for treatment planning purpose by using RPM and 4-dimensional computed tomography simulator. Visual gross tumor volume (GTV) and internal target volume (ITV) that each of the observer 1 and observer 2 has set were measured and compared on the CT image of each respiratory interval. Moreover, the amplitude of movement of tumor was measured by measuring the center of mass (COM) at the phase of 0% which is the end-inspiration (EI) and at the phase of 50% which is the end-exhalation (EE). In addition, both observers established treatment plan that applied the 2 respiratory periods, and mean dose to normal lung (MDTNL) was compared and analyzed through dose-volume histogram (DVH). Moreover, normal tissue complication probability (NTCP) of the normal lung volume was compared by using dose-volume histogram analysis program (DVH analyzer v.1) and statistical analysis was performed in order to carry out quantitative evaluation of the measured data. Results: As the result of the analysis of the treatment plan that applied the 'restricted respiratory period' of the observer 1 and observer 2, there was reduction rate of 38.75% in the 3-dimensional direction movement of the tumor in comparison to the 'free respiratory period' in the case of the observer 1, while there reduction rate was 41.10% in the case of the observer 2. The results of measurement and comparison of the volumes, GTV and ITV, there was reduction rate of $14.96{\pm}9.44%$ for observer 1 and $19.86{\pm}10.62%$ for observer 2 in the case of GTV, while there was reduction rate of $8.91{\pm}5.91%$ for observer 1 and $15.52{\pm}9.01%$ for observer 2 in the case of ITV. The results of analysis and comparison of MDTNL and NTCP illustrated the reduction rate of MDTNL $3.98{\pm}5.62%$ for observer 1 and $7.62{\pm}10.29%$ for observer 2 in the case of MDTNL, while there was reduction rate of $21.70{\pm}28.27%$ for observer 1 and $37.83{\pm}49.93%$ for observer 2 in the case of NTCP. In addition, the results of analysis of correlation between the resultant values of the 2 observers, while there was significant difference between the observers for the 'free respiratory period', there was no significantly different reduction rates between the observers for 'restricted respiratory period. Conclusion: It was possible to verify the usefulness and appropriateness of 'restricted respiratory period' at the time of respiration controlled radiotherapy on non-small cell lung cancer patient as the treatment plan that applied 'restricted respiratory period' illustrated relative reduction in the evaluation factors in comparison to the 'free respiratory period.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.67-72
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• 2010

Purpose: In Asan Medical Center we perform myocardial perfusion SPECT to evaluate cardiac event risk level for non-cardiac surgery patients. In case of patients with cancer, we check tumor metastasis using whole body bone scan and whole body PET scan and then perform myocardial perfusion SPECT to reduce unnecessary exam. In case of short term in patients, we perform $^{201}Tl$ myocardial perfusion SPECT after whole body bone scan a minimum 16 hours in order to reduce hospitalization period but it is still the actual condition in which the evaluation about the affect of the crosstalk contamination due to the each other dissimilar isotope administration doesn't properly realize. So in our experiments, we try to evaluate crosstalk contamination influence on $^{201}Tl$ myocardial perfusion SPECT using anthropomorphic torso phantom and patient's data. Materials and Methods: From 2009 August to September, we analyzed 87 patients with $^{201}Tl$ myocardial perfusion SPECT. According to $^{201}Tl$ myocardial perfusion SPECT yesterday whole body bone scan possibility of carrying out, a patient was classified. The image data are obtained by using the dual energy window in $^{201}Tl$ myocardial perfusion SPECT. We analyzed $^{201}Tl$ and $^{99m}Tc$ counts ratio in each patients groups obtained image data. We utilized anthropomorphic torso phantom in our experiment and administrated $^{201}Tl$ 14.8 MBq (0.4 mCi) at myocardium and $^{99m}Tc$ 44.4 MBq (1.2 mCi) at extracardiac region. We obtained image by $^{201}Tl$ myocardial perfusion SPECT without gate method application and analyzed spatial resolution using Xeleris ver 2.0551. Results: In case of $^{201}Tl$ window and the counts rate comparison result yesterday whole body bone scan of being counted in $^{99m}Tc$ window, the difference in which a rate to 24 hours exponential-functionally notes in 1:0.114 with Ventri (GE Healthcare, Wisconsin, USA), 1:0.249 after the bone tracer injection in 12 hours in 1:0.411 with 1:0.79 with Infinia (GE healthcare, Wisconsin, USA) according to a reduction a time-out was shown (Ventri p=0.001, Infinia p=0.001). Moreover, the rate of the case in which it doesn't perform the whole body bone scan showed up as the average 1:$0.067{\pm}0.6$ of Ventri, and 1:$0.063{\pm}0.7$ of Infinia. According to the phantom after experiment spatial resolution measurement result, and an addition or no and time-out of $^{99m}Tc$ administrated, it doesn't note any change of FWHM (p=0.134). Conclusion: Through the experiments using anthropomorphic torso phantom and patients data, we found that $^{201}Tl$ myocardium perfusion SPECT image later carried out after the bone tracer injection with 16 hours this confirmed that it doesn't receive notable influence in spatial resolution by $^{99m}Tc$. But this investigation is only aimed to image quality, so it needs more investigation in patient's radiation dose and exam accuracy and precision. The exact guideline presentation about the exam interval should be made of the validation test which is exact and in which it is standardized about the affect of the crosstalk contamination according to the isotope use in which it is different later on.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.624-629
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• 2009

Background: Making the histologic diagnosis of small pulmonary nodules and ground glass opacity (GGO) lesions is difficult. CT-guided percutaneous needle biopsies often fail to provide enough specimen for making the diagnosis. Video-assisted thoracoscopic surgery (VATS) can be inefficient for treating non-palpable lesions. Preoperative localization of small intrapulmonary lesions provides a more obvious target to facilitate performing intraoperative. resection. We evaluated the efficacy of CT-guided localization with using a hook wire and this was followed by VATS for making the histologic diagnosis of small intrapulmonary nodules and GGO lesions. Material and Method: Eighteen patients (13 males) were included in this study from August 2005 to March 2008. 18 intrapulmonary lesions underwent preoperative localization by using a CT-guided a hook wire system prior to performing VATS resection for intrapulmonary lesions and GGO lesions. The clinical data such as the accuracy of localization, the rate of conversion-to-thoracotomy, the operation time, the postoperative complications and the histology of the pulmonary lesion were retrospectively collected. Result: Eighteen VATS resections were performed in 18 patients. Preoperative CT-guided localization with a hook-wire was successful in all the patients. Dislodgement of a hook wire was observed in one case. There was no conversion to thoracotomy, The median diameter of lesions was 8 mm (range: $3{\sim}15\;mm$). The median depth of the lesions from the pleural surfaces was 5.5 mm (range: $1{\sim}30\;mm$). The median interval between preoperative CT-guided with a hook-wire and VATS was 34.5 min (range: ($10{\sim}226$ min). The median operative time was 43.5.min (range: $26{\sim}83$ min). In two patients, clinically insignificant pneumothorax developed after CT-guided localization with a hook-wire and there were no other complications. Histological examinations confirmed 8 primary lung cancers, 3 cases of metastases, 3 cases of inflammation, 2 intrapulmonary lymph nodes and 2 other benign lesions. Conclusion: CT-guided localization with a hook-wire followed by VATS for treating small intrapulmonary nodules and GGO lesions provided a low conversion thoracotomy rate, a short operation time and few localization-related or postoperative complications. This procedure was efficient to confirm intrapulmonary lesions and GGO lesions.

• The Korean Journal of Physiology
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• v.18 no.2
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• pp.151-162
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• 1984

The mechanism of the contractile response of longitudial muscle of rabbit ileum to substance P (SP) has been investigated. The contractions in rabbit ileum under various conditions were recorded isometrically The following results were obtained. 1) The contractions by SP increased according to concentrations. SP·induced contraction was not sustained but faded rapidly at $10^{-7}M$. The response to the commutative addition of SP was decreased in comparison to the response to separate administration of each concentration . 2) The response to $10^{-8}M$ SP after 5 min application cf $10^{-7}M$ SP was increased with increasing the time interval between the administration of $10^{-7}$ and $10^{-8}M$ SP. 3) The treatment of rabbit ileum by $10^{-7}M$ SP for 5 min didn't decrease the response to $10^{-6}M$ acetylcholine. 4) $10^{-6}M$ atropine had no effect of the contractile response to $10^{-7}M$ SP. The response to $10^{-7}M$ SP was normal or subnormal in the presence of 3 mM tetraethylammonium(TEA). 5) 100k solution, $10^{-4}M$ ouabain, and Na-free solution inhibited the response to $10^{-8}M$ SP and 3 mM TEA completely, and to $10^{-7}M$ SP incompletely. 3 mM TEA induced a considerable contraction in K-free solution, but $10^{-8}M$ SP didn't induce the contraction. $10^{-6}M$ norepinephrine decreased the contractile responses to SP and TEA. 6) The contractile response to $10^{-7}M$ SP was dependent on the extracellular $Ca^{2+}$ concentrations to 1.8 mM. 7) The contractile response to $10^{-7}M$ SP remained 15% of the maximal response after bathing the ileum in a Ca-free solution for 2.5 min. 8) The responsiveness to SP was completely lost within 10 min of bathing in Ca-free solution, but was restored by the exposure to $Ca^{2+}$. The restorative effect of $Ca^{2+}$ depended on the concentration of $Ca^{2+}$, and on time for which the tissue exposed to this $Ca^{2+}$ concentration. These results suggest that there are two mechanisms of the action by which the low concentrations of substance P causes the contraction of intestinal smooth muscle: the reduction of K conductance and a mechanism dependent on the extracellular $Ca^{2+}$, and that high concentration of SP may elicit a contraction by releasing $Ca^{2+}$ from an intracellular store, which is not as sensitive to removal of extracellular $Ca^{2+}$ or as easily accessible to EGTA as the extracellular space of the muscle. The location of this store is not known; it may be associated with the internal side of the cell membrane.

• The Korean Nurse
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• v.36 no.1
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• pp.77-96
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• 1997

The duty shifts of hospital nurses not only affect nurses' physical and mental health but also present various personnel management problems which often result in high turnover rates. In this context a study was carried out from October to November 1995 for a period of two months to find out the status of hospital nurses' duty shift patterns, and preferred duty hours and fixed duty shifts. The study population was 867 RNs working in five general hospitals located in Seoul and its vicinity. The questionnaire developed by the writer was used for data collection. The response rate was 85.9 percent or 745 returns. The SAS program was used for data analysis with the computation of frequencies, percentages and Chi square test. The findings of the study are as follows: 1. General characteristics of the study population: 56 percent of respondents was (25 years group and 76.5 percent were "single": the predominant proportion of respondents was junior nursing college graduates(92.2%) and have less than 5 years nursing experience in hospitals(65.5%). For their future working plan in nursing profession, nearly 50% responded as uncertain The reasons given for their career plan was predominantly 'personal growth and development' rather than financial reasons. 2. The interval for rotations of duty stations was found to be mostly irregular(56.4%) while others reported as weekly(16.1%), monthly(12.9%), and fixed terms(4.6%). 3. The main problems related to duty shifts particularly the evening and night duty nurses reported were "not enough time for the family, " "afraid of security problems after the work when returning home late at night." and "lack of leisure time". "problems in physical and physiological adjustment." "problems in family life." "lack of time for interactions with fellow nurses" etc. 4. The forty percent of respondents reported to have '1-2 times' of duty shift rotations while all others reported that '0 time'. '2-3 times'. 'more than 3 times' etc. which suggest the irregularity in duty shift rotations. 5. The majority(62.8%) of study population found to favor the rotating system of duty stations. The reasons for favoring the rotation system were: the opportunity for "learning new things and personal development." "better human relations are possible. "better understanding in various duty stations." "changes in monotonous routine job" etc. The proportion of those disfavor the rotating 'system was 34.7 percent. giving the reasons of"it impedes development of specialization." "poor job performances." "stress factors" etc. Furthermore. respondents made the following comments in relation to the rotation of duty stations: the nurses should be given the opportunity to participate in the. decision making process: personal interest and aptitudes should be considered: regular intervals for the rotations or it should be planned in advance. etc. 6. For the future career plan. the older. married group with longer nursing experiences appeared to think the nursing as their lifetime career more likely than the younger. single group with shorter nursing experiences ($x^2=61.19.{\;}p=.000;{\;}x^2=41.55.{\;}p=.000$). The reason given for their future career plan regardless of length of future service, was predominantly "personal growth and development" rather than financial reasons. For further analysis, the group those with the shorter career plan appeared to claim "financial reasons" for their future career more readily than the group who consider the nursing job as their lifetime career$(x^2$= 11.73, p=.003) did. This finding suggests the need for careful .considerations in personnel management of nursing administration particularly when dealing with the nurses' career development. The majority of respondents preferred the fixed day shift. However, further analysis of those preferred evening shift by age and civil status, "< 25 years group"(15.1%) and "single group"(13.2) were more likely to favor the fixed evening shift than > 25 years(6.4%) and married(4.8%)groups. This differences were statistically significant ($x^2=14.54, {\;}p=.000;{\;}x^2=8.75, {\;}p=.003$). 7. A great majority of respondents(86.9% or n=647) found to prefer the day shifts. When the four different types of duty shifts(Types A. B. C, D) were presented, 55.0 percent of total respondents preferred the A type or the existing one followed by D type(22.7%). B type(12.4%) and C type(8.2%). 8. When the condition of monetary incentives for the evening(20% of salary) and night shifts(40% of. salary) of the existing duty type was presented. again the day shift appeared to be the most preferred one although the rate was slightly lower(66.4% against 86.9%). In the case of evening shift, with the same incentive, the preference rates for evening and night shifts increased from 11.0 to 22.4 percent and from 0.5 to 3.0 percent respectively. When the age variable was controlled. < 25 yrs group showed higher rates(31.6%. 4.8%) than those of > 25 yrs group(15.5%. 1.3%) respectively preferring the evening and night shifts(p=.000). The civil status also seemed to operate on the preferences of the duty shifts as the single group showed lower rate(69.0%) for day duty against 83. 6% of the married group. and higher rates for evening and night duties(27.2%. 15.1%) respectively against those of the married group(3.8%. 1.8%) while a higher proportion of the married group(83. 6%) preferred the day duties than the single group(69.0%). These differences were found to be statistically all significant(p=.001). 9. The findings on preferences of three different types of fixed duty hours namely, B, C. and D(with additional monetary incentives) are as follows in order of preference: B type(12hrs a day, 3days a wk): day shift(64.1%), evening shift(26.1%). night shift(6.5%) C type(12hrs a day. 4days a wk) : evening shift(49.2%). day shift(32.8%), night shift(11.5%) D type(10hrs a day. 4days a wk): showed the similar trend as B type. The findings of higher preferences on the evening and night duties when the incentives are given. as shown above, suggest the need for the introductions of different patterns of duty hours and incentive measures in order to overcome the difficulties in rostering the nursing duties. However, the interpretation of the above data, particularly the C type, needs cautions as the total number of respondents is very small(n=61). It requires further in-depth study. In conclusion. it seemed to suggest that the patterns of nurses duty hours and shifts in the most hospitals in the country have neither been tried for different duty types nor been flexible. The stereotype rostering system of three shifts and insensitiveness for personal life aspect of nurses seemed to be prevailing. This study seems to support that irregular and frequent rotations of duty shifts may be contributing factors for most nurses' maladjustment problems in physical and mental health. personal and family life which eventually may result in high turnover rates. In order to overcome the increasing problems in personnel management of hospital nurses particularly in rostering of evening and night duty shifts, which may related to eventual high turnover rates, the findings of this study strongly suggest the need for an introduction of new rostering systems including fixed duties and appropriate incentive measures for evenings and nights which the most nurses want to avoid, In considering the nursing care of inpatients is the round-the clock business. the practice of the nursing duty shift system is inevitable. In this context, based on the findings of this study. the following are recommended: 1. The further in-depth studies on duty shifts and hours need to be undertaken for the development of appropriate and effective rostering systems for hospital nurses. 2. An introduction of appropriate incentive measures for evening and night duty shifts along with organizational considerations such as the trials for preferred duty time bands, duty hours, and fixed duty shifts should be considered if good quality of care for the patients be maintained for the round the clock. This may require an initiation of systematic research and development activities in the field of hospital nursing administration as a part of permanent system in the hospital. 3. Planned and regular intervals, orientation and training, and professional and personal growth should be considered for the rotation of different duty stations or units. 4. In considering the higher degree of preferences in the duty type of "10hours a day, 4days a week" shown in this study, it would be worthwhile to undertake the R&D type studies in large hospital settings.

• Journal of Chest Surgery
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• v.41 no.3
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• pp.347-353
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• 2008

Background: Esophageal perforation is an emergency that. requires early diagnosis and effective treatment. A delay in diagnosis and treatment. significantly increases morbidity and mortality. Material and Method: Thirty-seven patients with esophageal perforation were surgically treated at our institutions between January 1990 and December 2006. We retrospectively reviewed the results of surgical treatment for esophageal perforation to understand the risk factors affecting survival inpatients. Result: Patients ranged in age from 21 to 87 years, with an average age of $52.7{\pm}16.98$ years. Thirty-one of the patients were men and six were women. There were 23 patients (62%) with spontaneous perforations, 10 patients (27%) with a traumatic perforation, and 4 patients (11%) with an iatrogenic perforation. The site of esophageal perforation was the cervical esophagus in 5 patients, the thoracic esophagus in 31 patients, and the abdominal esophagus in one patient. Twenty-nine patients underwent primary closure of the perforation and five patients had T-tube drainage. Exclusion-diversion procedures were performed in two patients and an esophagectomy was performed in one patient. There were six cases of mortality (16.22%) and 25 cases of postoperative complications in 15 patients (40.5%). Patients that were treated later than 24 hours after detection of the perforation showed a statistically significant high morbidity and mortality rate (p<0.05). Conclusion: The most important risk factor of esophageal perforation was the time interval between detection of the perforation and the initiation of treatment. A prompt diagnosis and effective treatment are necessary to decrease morbidity and mortality.

• Journal of Chest Surgery
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• v.41 no.3
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• pp.354-359
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• 2008

Background: Warfarin is used as an anticoagulant and it is mainly excreted by the liver metabolism (the R-form is mainly metabolized by cytochrome p450 3A4, and the S form by cytochrome p450 2C9). Rifampin is usually used for tuberculosis or endocarditis, and it is a representative drug that induces the CYP families, including 3A4 and 2C9. The anticoagulation effect of warfarin decreases through the increased metabolism that's due to the induction of enzymes, and this iscaused by rifampin when patients take these two medicines together. No one has suggested appropriate guidelines regarding this drug interaction even though an appropriate adjustment of warfarin's dosage is needed. We examined the drug interaction in patients who received warfarin-rifampin combination therapy according to the time interval, and the factors affecting drug interaction were analyzed. Based on the data, we tried to determine the clinically available warfarin dosage guidelines before and after taking this drug combination. Material and Method: We reviewed the OO University Hospital anticoagulation service team's follow up sheets that were filled out from Jan '1998 to Sep 2006 for the patient who took warfarin - rifampin combination therapy (n=15). Result: The average INR of all the patient before rifampin administration was $2.25{\pm}0.52$ $(mean{\pm}SD)$, and that value for the first 100 days after rifampin administration was $1.98{\pm}0.28$. The p value for these two sets of data showed no correlation (paired t-test, p>0.05). The average INR of all the patient before rifampin cessation was $2.19{\pm}0.34$, and the value after rifampin cessation was $2.49{\pm}0.43$. The p value of these two showed correlation (paired t-test, p<0.05) but the average INR falls between the therapeutic INR range. Conclusion: The warfarin dose adjustment equation of before and after warfarin-rifampin combination therapy was derived based on this study's results because the warfarin dosage adjustment of the anticoagulation service team was considered appropriate.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.6
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• pp.185-196
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• 2015

Energy aware server clusters aim to reduce power consumption at maximum while keeping QoS(Quality of Service) compared to energy non-aware server clusters. They adjust the power mode of each server in a fixed or variable time interval to let only the minimum number of servers needed to handle current user requests ON. Previous studies on energy aware server cluster put efforts to reduce power consumption further or to keep QoS, but they do not consider energy efficiency well. In this paper, we propose an energy efficient cluster management based on autonomous learning for energy aware server clusters. Using parameters optimized through autonomous learning, our method adjusts server power mode to achieve maximum performance with respect to power consumption. Our method repeats the following procedure for adjusting the power modes of servers. Firstly, according to the current load and traffic pattern, it classifies current workload pattern type in a predetermined way. Secondly, it searches learning table to check whether learning has been performed for the classified workload pattern type in the past. If yes, it uses the already-stored parameters. Otherwise, it performs learning for the classified workload pattern type to find the best parameters in terms of energy efficiency and stores the optimized parameters. Thirdly, it adjusts server power mode with the parameters. We implemented the proposed method and performed experiments with a cluster of 16 servers using three different kinds of load patterns. Experimental results show that the proposed method is better than the existing methods in terms of energy efficiency: the numbers of good response per unit power consumed in the proposed method are 99.8%, 107.5% and 141.8% of those in the existing static method, 102.0%, 107.0% and 106.8% of those in the existing prediction method for banking load pattern, real load pattern, and virtual load pattern, respectively.

• Korean Journal of Remote Sensing
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• v.28 no.4
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• pp.409-420
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• 2012

Since the Industrial Revolution, CO2 levels have been increasing with climate change. In this study, Analyze time-series changes in snow cover quantitatively and predict the vanishing point of snow cover statistically using remote sensing. The study area is Mt. Kilimanjaro, Tanzania. 23 image data of Landsat-5 TM and Landsat-7 ETM+, spanning the 27 years from June 1984 to July 2011, were acquired. For this study, first, atmospheric correction was performed on each image using the COST atmospheric correction model. Second, the snow cover area was extracted using the NDSI (Normalized Difference Snow Index) algorithm. Third, the minimum height of snow cover was determined using SRTM DEM. Finally, the vanishing point of snow cover was predicted using the trend line of a linear function. Analysis was divided using a total of 23 images and 17 images during the dry season. Results show that snow cover area decreased by approximately $6.47km^2$ from $9.01km^2$ to $2.54km^2$, equivalent to a 73% reduction. The minimum height of snow cover increased by approximately 290 m, from 4,603 m to 4,893 m. Using the trend line result shows that the snow cover area decreased by approximately $0.342km^2$ in the dry season and $0.421km^2$ overall each year. In contrast, the annual increase in the minimum height of snow cover was approximately 9.848 m in the dry season and 11.251 m overall. Based on this analysis of vanishing point, there will be no snow cover 2020 at 95% confidence interval. This study can be used to monitor global climate change by providing the change in snow cover area and reference data when studying this area or similar areas in future research.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.710-715
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• 2010

Background: Video-assisted thoracic surgery (VATS) became common in the treatment of spontaneous pneumothorax (SP). Therefor we've reviewed the recurrence rate after VATS and analysed the factors affecting recurrent pneumothorax after VATS on this study. Material and Method: This retrospective analysis was performed on 321 patients of SP who had undergone VATS from Jan. 2001 to Dec. 2008. The two groups were divided as follow: group A, non-recurrent group (298 patients: 93%); and group B, recurrent group (26 patients: 7%); the two groups were analysed retrospectively. Result: The average age of the study groups were $20.9{\pm}4.3$ years old in recurrent group vs. $25.9{\pm}11.7$ years old in non-recurrent group with statistical significance (p < 0.05). There were no statistical significance in male to female ratio, height/weight ratio, location of pneumothorax, smoking history, operative time, duration of drain, hospital stay, indication of opertion and incidence rate. Average length of duration in recurrence was 12.9 months. There was 22 (95.7%) recurrent patients after VATS within 4 year period among recurrent group. Treatment methods in 23 of recurrent patients were, 8 (VATS), 2 (Axillary thoracotomy) with 15% or more in amount of pneumothorax and 7 (7 Fr. chest tube), 6 (nasal 02) with 15% or less in amount of pneumothorax. Among 10 cases of reoperation, there were 3 cases of over looking type and 7 cases of new growing type. There was no additional recurrence after these procedures were given. Conclusion: There was higher recurrence rate in younger age after VATS thus for those under 20 yrs old, detailed and possible preoperative warning for recurrence is warranted. Most recurrence occured within 4 year period, thus for this reason, regular interval based follow up with chest x-ray study is suggested during this period.