• Radiation Oncology Journal
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• v.22 no.3
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• pp.165-176
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• 2004

Purpose: Firstly, to analyze facto in terms of radiation treatment that might potentially cause subfrontal relapse in two patients who had been treated by craniospinal irradiation (CSI) for medulloblastoma, Secondly, to explore an effective salvage treatment for these relapses. Materials and Methods: Two patients who had high-risk disease (T3bMl, T3bM3) were treated with combined chemoradiotherapy CT-simulation based radiation-treatment planning (RTP) was peformed. One patient who experienced relapse at 16 months after CSI was treated with salvage surgery followed by a 30.6 Gy IMRT (intensity modulated radiotherapy). The other patient whose tumor relapsed at 12 months after CSI was treated by surgery alone for the recurrence. To investigate factors that might potentially cause subfrontal relapse, we evaluated thoroughly the charts and treatment planning process including portal films, and tried to find out a method to give help for placing blocks appropriately between subfrotal-cribrifrom plate region and both eyes. To salvage subfrontal relapse in a patient, re-irradiation was planned after subtotal tumor removal. We have decided to treat this patient with IMRT because of the proximity of critical normal tissues and large burden of re-irradiation. With seven beam directions, the prescribed mean dose to PTV was 30.6 Gy (1.8 Gy fraction) and the doses to the optic nerves and eyes were limited to 25 Gy and 10 Gy, respectively. Results: Review of radiotherapy Portals clearly indicated that the subfrontal-cribriform plate region was excluded from the therapy beam by eye blocks in both cases, resulting in cold spot within the target volume, When the whole brain was rendered in 3-D after organ drawing in each slice, it was easier to judge appropriateness of the blocks in port film. IMRT planning showed excellent dose distributions (Mean doses to PTV, right and left optic nerves, right and left eyes: 31.1 Gy, 14.7 Gy, 13.9 Gy, 6.9 Gy, and 5.5 Gy, respectively. Maximum dose to PTV: 36 Gy). The patient who received IMRT is still alive with no evidence of recurrence and any neurologic complications for 1 year. Conclusion: To prevent recurrence of medulloblastoma in subfrontal-cribriform plate region, we need to pay close attention to the placement of eye blocks during the treatment. Once subfrontal recurrence has happened, IMRT may be a good choice for re-irradiation as a salvage treatment to maximize the differences of dose distributions between the normal tissues and target volume.

• Journal of Chest Surgery
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• v.29 no.5
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• pp.495-503
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• 1996

The bidirectional cavopulmonary shunt may be useful as an intermediate procedure before Fontal oper- ation in high-risk patients, because it provides adequate relief of cyanosis and relief of ventricular volume overload. But there are no established theory about the effects of bidirectional cavopulmonary shunt on pulmonary arterial development. The purpose of this article is a study of changes of pulmonary artery size after bidirectional cavopulmonary shunt. Ca diac catheterization and angiography procedures were done on 19 patients who underwent bidirectional cavopulmonary shunt from February 1992 to July 1994, their results were reviewed. Preoperative cardiac catheterization and angiography procedures were performed at a mean interval of ).8 $\pm$4.8($\pm$SEM) months before surgery and following catheterization at a mean postoperative interval of 19.6 $\pm$4.8 months. Pulmonary arterial sixte measurement were standardized for body surface area(Pulmon- arty artery index), and for diameter of descending thoracic aorta(McGoon ratio). Patient's age, body stir- face area, pulmonary angioplasty, preoperative McGoon ratio and follow-up intervals were considered as variables. Before bidirectional cavopulmonary shunt, patient's mean age, body surface area, arterial 02 saturation, diameter of right pulmonary artery, diameter of left pulmonary artery, pulmonary artery Index, McGoon ratio were 13.7$\pm$15.6 months, 0.40$\pm$0.12m2, 71.4$\pm$12.4m2, 7.1$\pm$1.7mm, 6.2$\pm$1 , 191.8$\pm$82.7mm21m2, 1.73 $\pm$0.49, respectively. After bidirectional cavopulmonary shunt, the values were changed to 39.9 $\pm$ 16.2 months, 0.58$\pm$0.07 m2, 83.0$\pm$3.8m2, 9.0$\pm$ 1.5 mm, 7.7$\pm$2.0, 197.3$\pm$57.1 mm2/m2, 1.76$\pm$0.32, respect- ively With patients'development (age, body surf'ace area), diameters of pulmonary arteries were increased, but pulmonary artery indices and McGoon ratios were not changed. And there were no effects of age, body surf'ace area, amount of increased 02 saturation, pulmonary angiography and follow-up duration on the increment of pulmonary ar- tery size. But when the McGoon ratio was as low as 1.2, there were significant increase in postoperative pulmonary artery sizes. There was a significant correlation between preoperative pulmonary artery index (PAI) and McGoon ratio (MGR) ; PAI : MGRxl18.0-12.4 In conclusion, bidirectional cavopulmonary shunt provides adequate increment of arterial 02 saturation and does not increase the pulmonary artery size. Further investi ation is mandatory to evaluate the effect of pulsatile bidirectional cavopulmonary shunt on pulmonary artery growth.

• Journal of Chest Surgery
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• v.40 no.8
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• pp.536-545
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• 2007

Background: Compared to adult patients, mitral regurgitation in pediatric patients is uncommon and it shows a wide spectrum of morphologic abnormalities. We retrospectively evaluated the midterm results of mitral valve repair in pediatric patients. Material and Method: Between December 1993 and August 2006, mitral valve repair was performed in 35 patients who were aged less than 18 years, The mean age was $5.3{\pm}5.3$ years and the mean body weight was $20,0{\pm}16.3\;kg$. 18 patients had associated cardiac anomalies. The most common pathologic finding was leaflet prolapse (n=17). The most common method of repair was the double orifice technique (n=15). Result: There was no early mortality. Eight patients underwent reoperation (24.2%), and five of them required mitral valve replacement. Among the four ring annuloplasty cases, two have developed mitral stenosis. Four out of the 14 double orifice cases required reoperation. One case of early mortality and one case of late mortality occurred in the reoperation cases. The 5-year survival rate and the freedom from reoperation rate were $93.3{\pm}4.6%$ and $76.1{\pm}8.2%$, respectively. The 5-year freedom from mitral valve replacement rate was $83.6{\pm}6.7%$. There was no significant risk factor for reoperation. Conclusion: The midterm results of mitral valve repair are very acceptable in pediatric patients compared to the adult cases, although the reoperation rate is slightly higher.

• Journal of Oral Medicine and Pain
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• v.34 no.1
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• pp.91-102
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• 2009

Condylar resorption, or condylysis can be defined as progressive alteration of condylar shape and decrease in mass. Condylar resorption is a poorly understood progressive disease that affects the TMJ and that can result in malocclusion, facial disfigurement, TMJ dysfunction, and pain. The aim of this study was to investigate clinical assessment and cephalometric characteristics in 224 patients with condylar resorption, who visited in the Department of Oral Medicine Kyungpook National University Hospital at 2006, by use of panorama, transcranial view and lateral cephalometric radiograph. The results were as follows; 1. Clinical assessment 1) Total number of patients who visited with chief complaints of TMD were 2419 and 224 (9.3%) among them revealed the condylar resorption, Among patients group with condylar resorption, female was 183 and male was 41, females were predominant. 2) Patient's age ranged from 12 to 70 and mean age was 30.6 years old with a strong predominance for 10s and 20s. Distribution of a showed as follows; 10s was 26.3%, 20s was 34,8%, 30s was 13.8%, 40s was 11.2%, 50s was 7.1%, 60s was 6.3% and 70s was 0.4%. 3) Most of the patients had parafunctional habit. 4) The case of showing the pain in condylar resorption was 145, the case of not showing the pain was 79. 5) Treatment duration of the patients was relatively short. 2. Cephalometric Characteristics 1) ANB which means the retruding of the mandible increased significantly than normal group. The ANB of female was lager than male group as the means of ANB were 5.05 in female and 3.57 in male, 2) SN-GoMe and FMA increased in resorption patients, but FH-PP did not show any significant difference. The FMA of female was lager than male group as the means were 31.69 in female and 30.44 in male. 3) Total posterior facial height was significantly smaller and total anterior facial height showed no significant increase as compared with those of the normal group. Condylar resorption was predominant in young female which was caused by more vertical facial pattern in female than male and increase of parafunctional habit in young age. It was thought that the patients who have a risk factor increasing the compressive stress at condyle caused by obliquely inclined masseter and medial pterygoid show high prevalence of condylar resorption.

• Radiation Oncology Journal
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• v.22 no.2
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• pp.115-123
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• 2004

Purpose : This retrospective study was conducted to compare early preliminary results of breast conservation therapy (BCT) with mastectomy In early breast cancer. Materials and Methods : We evaluated 171 women with AJCC stage I and II breast cancer who had been treated at Kangnam St. Mary's Hospital from March 1989 to August 1996. Eighty-eight patients underwent mastectomy and 85 patients did conservative surgery with breast irradiation. in the BCT group, all patients received whole breast irradiation to a total dose of 45$\~$50 Gy/5$\~$6 wks, followed by a boost to the original tumor site at least 60 Gy. Chemotherapy was administered to 29 (34.1$\%$) patients in BCT and 40 (45.5$\%$) in mastectomy, with various sequencing of surgery and/or radiation. We compared survival rate, patterns of failure in each treatment group and the prognostic factors that had a significant effect on treatment failure. The median follow-up time was 63 months (19$\~$111 months). Log rank test was used to estimate the prognostic factors for treatment failure. Results : Overall survival, disease free survival, locoregional recurrence and distant metastasis rates were not significantly different between the two treatment groups. During the follow-up period, 11 patients (12.5$\%$)in the mastectomy group and 10 patients (11.8%$\%$ in the BCT group were failed. Six local recurrences occurred after mastectomy and 5 after BCT Five patients fatted at distant site in mastectomy and 4 in BCT. Of the local recurrence cases, five of 6 mastectomy patients and 3 of S BCT patients were alive with no evidence of disease after salvage surgery and/or chemoirradiation. Our results indicated that the major influence on survival was distant metastasis. Unfortunately, control of distant metastasisis was not frequently achieved. Even with salvage systemic therapy or radiotherapy, most of distant metastasis patients died or had uncontrolled disease in both treatment groups: only one of 4 BCT patients and none of mastectomy patients were alive without disease. There was no apparent difference in the incidence rate of contralateral breast cancer and non-breast 2$^{nd}$ primary tumor between the two treatment groups. Univariate Log-rank test identified the N stage and the involved axillary LN number as distinct prognostic factors that were highly predictive of treatment failure in both treatment groups. Additionally, marginal status in BCT and histologic nuclear grade In the mastectomy group were risk factors for treatment fallure (p < 0.05). Concousion : Although further careful follow-up is necessary to confirm the trends evident In this serles, it would appear that patterns of failure and survival rate following conservative surgery and radiotherapy in early breast cancer are similar to those following mastectomy. The great majority of patients with local recurrence had an exellent salvage rate in both treatment groups. Therefore, these preliminary short term results support BCT as an equally effective management for early breast cancer as an alternative to mastectomy.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1252-1264
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• 1998

Background : Patients with established ARDS have a mortality rate that exceeds 50 percent despite of intensive care including artificial ventilation modality, Mortality has been associated with sepsis and organ failure preceding or following ARDS ; APACHE II score ; old age and predisposing factors. Revised ventilator strategy over last 10 years especially at ARDS appeared to improve the mortality of it. We retrospectively investigated 40 ARDS patients of respiratory-care unit to examine how these factors influence outcome. Methods : A retrospective investigation of 40 ARDS patients in respiratory-care unit with ventilator management over 46 months was performed. We investigated the clinical characteristics such as a risk factor, cause of death and mortality, and also parameters such as APACHE II score, number of organ dysfunction, and hypoxia score (HS, $PaO_2/FIO_2$) at day 1, 3, 7 of severe acute lung injury, and simultaneously the PEEP level and tidal volume. Results : Clinical conditions associated with ARDS were sepsis 50%, pneumonia 30%, aspiration pneumonia 20%, and mortality rate based on the etiology of ARDS was sepsis 50%, pneumonia 67%(p<0.01 vs sepsis), aspiration pneumonia 38%. Overall mortality rate was 60%. In 28 day-nonsurvivors, leading cause of death was severe sepsis(42.9%) followed by MOF(28.6%), respiratory failure(19.1 %), and others(9.5%). There were no differences in variables of age, sex, APACHE II score, HS, and numbers of organ dysfunction at day 1 of ARDS between 28-days survivor and nonsurvivors. In view of categorized variables of age(>70), APACHE II score(>26), HS(<150) at day 1 of ARDS, there were significant differences between 28-days survivor and nonsurvivors(p<0.05). After day 1 of ARDS, the survivors have improved their APACHE II score, HS, numbers of organ dysfunction over the first 3d to 7d, but nonsurvivors did not improve over a seven-day course. There were significant differences in APACHE II score and numbers of organ dysfunction of day 3, 7 of ARDS, and HS of day 7 of ARDS between survivors and nonsurvivors(p<0.05). Fatality rate of ARDS has been declined from 68% to less than 40% between 1995 and 1998. There were no differences in APACHE II score, HS, numbers of organ dysfunction, old age at presentation of ARDS. In last years, mean PEEP level was significantly higher and mean tidal volume was significantly lower than previous years during seven days of ARDS(p<0.01). Conclusions : Improvement of HS, APACHE II score, organ dysfunction over the first 3d to 7d is associated with increased survival Decline in ARDS fatality rates between 1995 and 1998 seems that this trend must be attributed to improved supportive therapy including at least high PEEP instead of conventional-least PEEP approach in ventilator management of acute respiratory distress syndrome.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.813-822
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• 1998

Background: Extubation is recommended to be performed at minimum pressure support (PSmin) during the pressure support ventilation (PSV). In field, physicians sometimes perform additional 1 hr T-piece trial to the patient at PSmin to reduce re-intubation risk. Although it provides confirmation of patient's breathing reserve, weaning could be delayed due to increased airway resistance by endotracheal tube. Methods: To investigate the effect of additional 1 hr T-piece trial on weaning outcome, a prospective study was done in consecutive 44 patients who had received mechanical ventilation more than 3 days. Respiratory mechanics, hemodymic, and gas exchange measurements were done and the level of PSmin was calculated using the equation (PSmin=peak inspiratory flow rate $\times$ total ventilatory system resistance) at the 15cm $H_2O$ of pressure support. At PSmin, the patients were randomized into intervention (additional 1 hr T-piece trial) and control (extubation at PSmin). The measurements were repeated at PSmm, during weaning process (in cases of intervention), and after extubation. The weaning success was defined as spontaneous breathing more than 48hr after extubation. In intervention group, failure to continue weaning process was also considered as weaning failure. Results: Thirty-six patients with 42 times weaning trial were satisfied to the protocol. Mean PSmin level was 7.6 (${\pm}1.9$)cm $H_2O$. There were no differences in total ventilation times (TVT), APACHE III score, nutritional indices, and respiratory mechanics at PSmin between 2 groups. The weaning success rate and re-intubation rate were not different between intervention group (55% and 18% in each) and control group (70% and 20% in each) at first weaning trial. Work of breathing, pressure time product, and tidal volume were aggravated during 1 hr T-piece trial compared to those of PSmin in intervention group ($10.4{\pm}1.25$ and $1.66{\pm}1.08$ J/L in work of breathing) ($191{\pm}232$ and $287{\pm}217$cm $H_2O$ s/m in pressure time product) ($0.33{\pm}0.09$ and $0.29{\pm}0.09$ L in tidal volume) (P<0.05 in each). As in whole, TVT, and tidal volume at PSmin were significantly different between the patients with weaning success ($246{\pm}195$ hr, $0.43{\pm}0.11$ L) and the those with weaning failure ($407{\pm}248$ hr, $0.35{\pm}0.10$L) (P<0.05 in each). Conclusion : There were no advantage to weaning outcome by addition of 1 hr T-piece trial compared to prompt extubation to the patient at PS min.

• Journal of Intelligence and Information Systems
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• v.20 no.1
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• pp.177-193
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• 2014

Over the past decade, there has been a rapid diffusion of electronic commerce and a rising number of interconnected networks, resulting in an escalation of security threats and privacy concerns. Electronic commerce has a built-in trade-off between the necessity of providing at least some personal information to consummate an online transaction, and the risk of negative consequences from providing such information. More recently, the frequent disclosure of private information has raised concerns about privacy and its impacts. This has motivated researchers in various fields to explore information privacy issues to address these concerns. Accordingly, the necessity for information privacy policies and technologies for collecting and storing data, and information privacy research in various fields such as medicine, computer science, business, and statistics has increased. The occurrence of various information security accidents have made finding experts in the information security field an important issue. Objective measures for finding such experts are required, as it is currently rather subjective. Based on social network analysis, this paper focused on a framework to evaluate the process of finding experts in the information security field. We collected data from the National Discovery for Science Leaders (NDSL) database, initially collecting about 2000 papers covering the period between 2005 and 2013. Outliers and the data of irrelevant papers were dropped, leaving 784 papers to test the suggested hypotheses. The co-authorship network data for co-author relationship, publisher, affiliation, and so on were analyzed using social network measures including centrality and structural hole. The results of our model estimation are as follows. With the exception of Hypothesis 3, which deals with the relationship between eigenvector centrality and performance, all of our hypotheses were supported. In line with our hypothesis, degree centrality (H1) was supported with its positive influence on the researchers' publishing performance (p<0.001). This finding indicates that as the degree of cooperation increased, the more the publishing performance of researchers increased. In addition, closeness centrality (H2) was also positively associated with researchers' publishing performance (p<0.001), suggesting that, as the efficiency of information acquisition increased, the more the researchers' publishing performance increased. This paper identified the difference in publishing performance among researchers. The analysis can be used to identify core experts and evaluate their performance in the information privacy research field. The co-authorship network for information privacy can aid in understanding the deep relationships among researchers. In addition, extracting characteristics of publishers and affiliations, this paper suggested an understanding of the social network measures and their potential for finding experts in the information privacy field. Social concerns about securing the objectivity of experts have increased, because experts in the information privacy field frequently participate in political consultation, and business education support and evaluation. In terms of practical implications, this research suggests an objective framework for experts in the information privacy field, and is useful for people who are in charge of managing research human resources. This study has some limitations, providing opportunities and suggestions for future research. Presenting the difference in information diffusion according to media and proximity presents difficulties for the generalization of the theory due to the small sample size. Therefore, further studies could consider an increased sample size and media diversity, the difference in information diffusion according to the media type, and information proximity could be explored in more detail. Moreover, previous network research has commonly observed a causal relationship between the independent and dependent variable (Kadushin, 2012). In this study, degree centrality as an independent variable might have causal relationship with performance as a dependent variable. However, in the case of network analysis research, network indices could be computed after the network relationship is created. An annual analysis could help mitigate this limitation.

• Radiation Oncology Journal
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• v.16 no.1
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• pp.17-25
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• 1998

Purpose : Although local recurrence rates of stomach cancer after radiocal surgery have been reported in the range of $30-70\%$, the role of postoperative adjuvant therapy has not been established. We report the result of radiotherapy in resected stomach cancer with positive surgical margin to elucidate the role of postoperative radiotherapy. Materials and Methods : From June 1991 to August 1996, twenty five patients with positive surgical margins after radical gastrectomy were treated with postoperative radiotherapy and chemotherapy. Median dose of radiation was 55.8Gy and the range was 44.6-59.4Gy. Second cycle of chemotherapy was delivered concurrently with radiation and total number of six cycles were delivered. Twenty three had adenocarcinoma and the other two had leiornyosarcoma. The numbers of patients with stage I B, II, III A, III B, and IV were 1, 2, 11, 10 and 1 respectively. Positive margins at distal end of the stomach were in 17 patients and proximal in 5. The other three patients had positive margin at the sites of adjacent organ invasion Minimum and median follow-up periods were 12 months and 18 months, respectively, Results : Twenty-four of 25 patients received prescribed radiation dose and RTOG grade 3 toxicity of UGI tract was observed in 3, all of which were weight loss more than $15\%$ of their pretreatment weight. But hematemesis. melena, intestinal obstruction or grade 4 toxicity were not found. Locoregional failure within the radiation field was observed in 7 patients, and distant metastasis in 10 patients. Sites of locoregional recurrences involve anastomosis/remnant stomach in 3, tumor bed/duodenal stump in 3, regional lymph node in 1 patient Peritoneal seeding occurred in 6, liver metastases months and median disease free survival time was 26 months. Stages andradiation dose were not significant prognostic factors for locoregional in 2, and distant nodes in 2 patients. Four year disease specificsurvival rate was $40\%$ and disease free survival was $48\%$. Median survival was 35 failures. Conculsion : Although all patients in this study had positive surgical margins, locoregional failure rate was $28\%$, and 4 year disease specific survival rate was $40\%$. Considering small number of patients and relatively short follow-up period, it is not certain that postoperative radiotherapy lowered locoregional recurrences. but we could find a Possibility of the role of postoperative radiotherapy in Patients with high risk factors.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.7-15
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• 2020

Purpose: In modern radiotherapy technology, several methods of image guided radiation therapy (IGRT) are used to deliver accurate doses to tumor target locations and normal organs, including CBCT (Cone Beam Computed Tomography) and other devices, ExacTrac System, other than CBCT equipped with linear accelerators. In previous studies comparing the two systems, positional errors were analysed rearwards using Offline-view or evaluated only with a Yaw rotation with the X, Y, and Z axes. In this study, when using CBCT and ExacTrac to perform 6 Degree of the Freedom(DoF) Online IGRT in a treatment center with two equipment, the difference between the set-up calibration values seen in each system, the time taken for patient set-up, and the radiation usefulness of the imaging device is evaluated. Materials and Methods: In order to evaluate the difference between mobile calibrations and exposure radiation dose, the glass dosimetry and Rando Phantom were used for 11 cancer patients with head circumference from March to October 2017 in order to assess the difference between mobile calibrations and the time taken from Set-up to shortly before IGRT. CBCT and ExacTrac System were used for IGRT of all patients. An average of 10 CBCT and ExacTrac images were obtained per patient during the total treatment period, and the difference in 6D Online Automation values between the two systems was calculated within the ROI setting. In this case, the area of interest designation in the image obtained from CBCT was fixed to the same anatomical structure as the image obtained through ExacTrac. The difference in positional values for the six axes (SI, AP, LR; Rotation group: Pitch, Roll, Rtn) between the two systems, the total time taken from patient set-up to just before IGRT, and exposure dose were measured and compared respectively with the RandoPhantom. Results: the set-up error in the phantom and patient was less than 1mm in the translation group and less than 1.5° in the rotation group, and the RMS values of all axes except the Rtn value were less than 1mm and 1°. The time taken to correct the set-up error in each system was an average of 256±47.6sec for IGRT using CBCT and 84±3.5sec for ExacTrac, respectively. Radiation exposure dose by IGRT per treatment was measured at 37 times higher than ExacTrac in CBCT and ExacTrac at 2.468mGy and 0.066mGy at Oral Mucosa among the 7 measurement locations in the head and neck area. Conclusion: Through 6D online automatic positioning between the CBCT and ExacTrac systems, the set-up error was found to be less than 1mm, 1.02°, including the patient's movement (random error), as well as the systematic error of the two systems. This error range is considered to be reasonable when considering that the PTV Margin is 3mm during the head and neck IMRT treatment in the present study. However, considering the changes in target and risk organs due to changes in patient weight during the treatment period, it is considered to be appropriately used in combination with CBCT.