• Journal of radiological science and technology
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• v.28 no.2
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• pp.105-110
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• 2005

Background/Aim : Common bile duct (CBD) stones may cause jaundice, cholangitis, or pancreatitis. Extracorporeal shock wave lithotripsy (ESWL) may be needed whenever endoscopic procedure are failed to extract common bile duct stones. The aim of this study is to provide the standard for patient's best choice on ESWL for treatment of CBD stones resistant to endoscopic extraction. Materials and Methods : Fourty-six patients failed in endoscopic stone extraction including mechanical lithotripsy were treated by ESWL. In all patients, endoscopic sphincterotomy and nasobiliary drainage tube was done before ESWL using the ultrasonography for stone localization with a spark-gap type lithotriptor. Patients were sedated with an intravenous injection of 50 mg of Demerol. None were treated under general anesthesia. Results : Overall complete clearance rate of CBD stone was 89.1% (41/46). In 82.6% of the patients, the stones were extracted endoscopically after ESWL, and spontaneous passage was observed in 6.5%. In the clearance rate after ESWL, there were no noticeable differences with regard to number (single: 82.8%, two or three: 100%, more than three: 100%) and size of the stone (less than 33mm: 92.9%, 33 mm or larger: 83.3%), whereas there were significant differences with regard to the ratio of sum of long-axis length of the all stones to sum of long-axis length of the CBD excluding stone (1:2.4, 1:2.1) and diameter of the largest stone to diameter of CBD excluding stone (1:0.9, 1:0.4) for patients with complete clearance compared with those without. Conclusion : We propose that stones without the fragments are travelable sufficient space in CBD or extractable sufficient diameter of CBD regardless of stone size and number should be treated by other technique to prevent time and cost consuming, such as percutaneous transhepatic cholangioscopylithotomy.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.157-164
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• 2012

The purpose of this study is to analyze the dose distribution when wedge filter is used in the various tissue electron density materials. The dose distribution was assessed that the enhanced dynamic wedge filter and physical wedge filter were used in the solid water phantom, cork phantom, and air cavity. The film dosimetry was suitable simple to measure 2D dose distribution. Therefore, the radiochromic films (Gafchromic EBT2, ISP, NJ, USA) were selected to measure and to analyze the dose distributions. A linear accelerator using 6 MV photon were irradiated to field size of $10{\times}10cm^2$ with 400 MUs. The dose distributions of EBT2 films were analyzed the in-field area and penumbra regions by using dose analysis program. In the dose distributions of wedge field, the dose from a physical wedge was higher than that from a dynamic wedge at the same electron density materials. A dose distributions of wedge type in the solid water phantom and the cork phantom were in agreements with 2%. However, the dose distribution in air cavity showed the large difference with those in the solid water phantom or cork phantom dose distributions. Dose distribution of wedge field in air cavity was not shown the wedge effect. The penumbra width, out of the field of thick and thin, was observed larger from 1 cm to 2 cm at the thick end. The penumbra of physical wedge filter was much larger average 6% than the dynamic wedge filter. If the physical wedge filter is used, the dose was increased to effect the scatter that interacted with photon and physical wedge. In the case of difference in electron like the soft tissue, lung, and air, the transmission, absorption, and scattering were changed in the medium at high energy photon. Therefore, the treatment at the difference electron density should be inhomogeneity correction in treatment planning system.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.1-8
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• 2008

The lateral strength test of bending type was done to investigate the lateral capacity of the double bolt connection of domestic larix glulam according to bolt spacing. In the shear specimen, which is bolted connection in the inserted plate type, the hole of bolt was made, changing the diameter of bolt (12 mm and 16 mm), the number of bolt (single bolt : control and double bolt), the direction of bolt row (in parallel to grain : Type-A and in perpendicular to grain : Type-B) and the bolt spacing (Type-A : 4 d and 7 d and Type-B : 3 d and 5 d). Lateral capacity and failure mode of bolt connection were compared according to conditions. In prototype design (KBCS, 2000), the reduction factor of the allowable shear resistance that the bolt spacing is reduced was calculated. The results were as follows. 1) Bearing stress per bolt in the single and double bolt connection of Type-A was directly proportional to bolt diameter and bolt spacing. Bearing stress of Type-B decreased as bolt diameter was increased, and decreased by 2~10% when bolt diameter was increased. 2) In the single bolt connection and the double bolt connection of Type-A, the splitted failure was formed in the edge direction. When the bolt spacing was 3 d in Type-B, bolt was yielded more in the part of tension than in the part of compression, and the splitted failure started at the bolt in the part of tension. In the 5 d spacing specimen, the bolt in the part of tension was yielded similarly to bolt in the part of compression, and the splitted failure started in the part of compression. 3) In the prototype design, the reduction factor was calculated by non-dimensionizing the yielding load in the standard of bolt spacing (Type A : 7 d and Type B : 5 d). In 12 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.87 and 0.55, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.55, respectively. In 16 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.96 and 0.76, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.77, respectively.

• Journal of Chest Surgery
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• v.29 no.11
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• pp.1218-1222
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• 1996

The reported incidence of postcardiotomy cardiogenic shock not responding to conventional therapy is still 0.1 to 0.8%. For this group of patients, more aggressive form of circulatory support must be employed. Centrifugal pumps are a ventricular assist device most commonly used on this purpose, due to low cost and easy availability. Currently, however, clinical experience of centrifugal pumps as a ventricular assist device is rarely reported in Korea. From January 1992 to January 1996, 2986 patients underwent cardiac operations on cardiopulmonary bypass at Seoul National University Hospital. Refractory postcardiotomy cardiac failure requring ventricular support with a Biomedicus centrifugal pump developed in ten of these patients. There were eight men and two women, ranged in age from nine years to 77 years with a mean of 50$\pm$20 years. The primary surgical procedures consisted of isolated coronary revascularization in four patients, combined coronary revascularization and aortic valve replacement in two, aortic dissection repair in two, pulmonary embolectomy in one, and heart transplantation in one. Of the ten patients, five had left ventricular assistance, one had right ventricular assistance, and four had biventricular assistance. Duration of ventricular assistance ranged from 24 to 175 hours, with a mean of 76$\pm$51 hours. Seven patients were weaned from ventricular assistance, and four of them discharged. The causes of death for nonsurvivors were progressive cardiac failure in two patients and multiorgan failure, intractable ventricular fibrillation, irreversible brain injury, and mechanical problem, respectively, in the other four. Survival was not predicted by time on cardiopulmonary bypass, aortic cross-clamp time, or duration of ventricular support. Major complications included bleeding(7), renal failure(6), infection(3) and neurologic complication(2). These results indicate that a centrifugal pump can provide reasonably satisfactory short-term circulatory support.

• Journal of Chest Surgery
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• v.39 no.4 s.261
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• pp.261-268
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• 2006

Background: Current vascular prostheses are still inadequate for reconstruction of small-diameter vessels. Autologous pericardium can be a good alternative for this purpose as it already possesses good blood compatibility and shows a mechanical behavior similar to that of natural arteries. However, the clinical use of autologous pericardial tissue as a small-diameter vascular graft has limitations due to mixed outcomes from uncertain biological behavior and difficulty to gain reliable patency results in animal experiments. To study this issue, we implanted fresh and glutaraldehyde-treated autologous pericardium as small-diameter arterial grafts in dogs, and compared their time-related changes histologically. Material and Method: As a form of 5mm-diameter arterial graft, one pair of autologous pericardial tissue was used for comparison between the glutaraldehyde-treated and the glutaraldehyde-untreated grafts in the bilateral carotid arteries in the same dog. The patency of the grafts were evaluated at regular intervals with Doppler ultrasonography. After the predetermined periods of 3 days, 2 weeks, 1 month, 3 months and 6 months, the grafts in each animal were explanted. The retrieved grafts were processed for light and electron microscopic analyses following gross observation. Result: Of 7 animals, 2 were excluded from the study because one died postoperatively due to bleeding and the other was documented as one side of the grafts being obstructed. All 10 grafts in the remaining 5 dogs were patent. Grossly, a variable degree of thromboses were observed in the luminal surfaces of the grafts at 3 days and 2 weeks, despite good patency. Pseudointimal smooth blood-contacting surfaces were developed in the grafts at f month and later. By light microscopy, mesothelial cell layers of the pericardial tissue were absent in all explanted grafts. Newly formed endothelial cell layers on the blood-contacting surface were observed in both the glutaraldehyde-treated and fresh grafts at 3 months and later. The collagen fibers became degraded by fragmentation in the fresh graft at 1 month and In the glutaraldehyde-treated graft at 3 months. At 6 months, the collagen layers were no longer visible in either the glutaraldehyde-treated or fresh grafts. By electron microscopy, a greater amount of coarse fibrin fibers were observed in the fresh grafts than in the glutaraldehyde-treated grafts and, more compact and well-arrayed layers were observed in the glutaraldehyde-treated grafts than in the fresh grafts. Conclusion: The glutaraldehyde-treated small-diameter pericardial arterial grafts showed a better endothelialization of the blood-contacting surface and a slower fragmentation of the collagen layers than the fresh grafts, although it has yet to be proven whether these differences are so significant as to affect the patency results between the groups.

• 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.

• Radiation Oncology Journal
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• v.23 no.2
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• pp.123-130
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• 2005

Purpose: We wanted to improve the setup reproducibility of breast cancer patients when utilizing a commercially available breast board for radiation therapy. The breast board was modified by using a new head rest and 2 types of board fixation devices. Materials and Methods: A conventional head/neck rest was modified to be positioned in various slots of the breast board, and it was fabricated 1 cm thinner to provide more comfort to a patient when the patient's neck was rotated. This rest improves the uncertainty of the daily setup. Also, the sagging problems at the left and right sides became negligible with the two types of board fixation devices: (1) the stair type, and (2) the arm type. The first device consists of an upper/lower holder with 4 stair-types of grooves and 4 rectangular Inserts. In order to cover the whole range of vertical setup of the breast board, 4 rectangular inserts were needed, and each covered 10 steps. The arm-type fixation device was also fabricated and attached to the breast board, It had two aluminum bars that were fixed by utilizing a lock-type of screw. These devises were evaluated with two volunteers in order to prove the effectiveness of the improved setup accuracy. Results; The developed cranio-caudal fixation device demonstrated that it could reduce the cranio-caudal error by nearly $55\%$ compared to the old device. As for left-and-right inclination, the stair-type and arm-type fixation devices can reduce the relative inclination by nearly $80\%$ and $90\%$, respectively, compared to the breast board without the fixation device. Conclusion: It was verified that the developed devices were effective for positioning the patients and for avoiding inclination of the breast board.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.486-496
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• 2011

A special mesenchymal tissue layer called perichondrium has a chondrogenic capacity and is a candidate tissue for engineering of cartilage. To overcome limited potential for chondrocyte proliferation and re-absorption, we studied a method of cartilage tissue engineering comprising chondrocyte-hydrogel pluronic complex (CPC) and cultured perichondrial cell sheet (cPCs) which entirely cover CPC. For effective cartilage regeneration, cell-sheet engineering technique of high-density culture was used for fabrication of cPCs. Hydrogel pluronic as a biomimetic cell carrier used for stable and maintains the chondrocytes. The human cPCs was cultured as a single layer and entirely covered CPC. The tissue engineered constructs were implanted into the dorsal subcutaneous tissue pocket on nude mice (n = 6). CPC without cPCs were used as a controls (N = 6). Engineered cartilage specimens were harvested at 12 weeks after implantation and evaluated with gross morphology and histological examination. Biological analysis was also performed for glycosaminoglycan (GAG) and type II collagen. Indeed, we performed additional in vivo studies of cartilage regeneration using canine large fullthickness chondrial defect model. The dogs were allocated to the experimental groups as treated chondrocyte sheets with perichondrial cell sheet group (n = 4), and chondrocyte sheets only group (n = 4). The histological and biochemical studies performed 12 weeks later as same manners as nude mouse but additional immunofluorescence study. Grossly, the size of cartilage specimen of cPCs covered group was larger than that of the control. On histological examination, the specimen of cPCs covered group showed typical characteristics of cartilage tissue. The contents of GAG and type II collagen were higher in cPCs covered group than that of the control. These studies demonstrated the potential of such CPC/cPCs constructs to support chondrogenesis in vivo. In conclusion, the method of cartilage tissue engineering using cPCs supposed to be an effective method with higher cartilage tissue gain. We suggest a new method of cartilage tissue engineering using cultured perichondrial cell sheet as a promising strategy for cartilage tissue reconstruction.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.135-142
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• 2011

Purpose : Hospital associated infection (HAI) caused by multidrug-resistant (MDR) microorganisms has been recognized as an important issue in the world, especially in critically ill patients such as the patients admitted in the intensive care unit. There are fewer papers about MDR-HAI in pediatric patients compared to adult patients. In this study, we investigated the incidence and associated factors of MDR-HAI in children admitted to the intensive care unit (ICU) of a university hospital. Methods : We retrospectively evaluated 135 children who were admitted in ICU for at least 3 days between January 2009 and December 2010. HAI cases were divided into MDR-HAI group and non-MDR-HAI group. Clinical characteristics and various associated factors were compared between those groups. Results : In 39 patients, 45 cases of ICU-related HAI were developed. ICU-related HAI incidence was 47.7 per 1000 patientdays. Thirty-six cases (80.0%) were MDR-HAI. Acinetobacter baumannii was isolated more commonly in MDR-HAI group. And the followings were found more frequently in MDR-HAI group than non-MDR-HAI group: medical condition as an indication for ICU admission, mechanical ventilation, urinary catheterization and previous use of broad-spectrum antibiotics. Among the risk factors, previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. Conclusion : ICU-related HAI incidence was higher than previously reported. Previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. To investigate the characteristics of MDR-HAI in children admitted in ICU, further studies with a larger sample size over a longer period of time are warranted.

• Childhood Kidney Diseases
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• v.14 no.1
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• pp.62-70
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• 2010

Purpose : The voiding cystourethrogram (VCUG) is the investigation of choice in detecting the vesicoureteral reflux in urinary tract infections in children. As it is a potentially distressing and invasive test, most of the parents are so concerned about the child's stress. In this study, we compared the difference of the state of anxiety of parents before and after the VCUG. Methods : We divided 68 parents whose children underwent VCUG into 2 groups; who have given an explanation about VCUG in detail using pictures (group 1) Vs. who have given an oral explanation only (group 2). All the parents submitted the same questionnaire 2 times before and after the VCUG, which consisted of State-Trait-Anxiety-Inventory X-I (STAI-X-I) and visual analog scale (VAS) on the perception of worry, anxiety, confusion and pain. Results : Before VCUG, the perception of pain was higher in group 1 (P<0.05). After VCUG, the anxiety and confusion were significantly higher in group 2 than group 1 (P<0.05). In group 1, STAI-X-I scores, the perception of worry and anxiety were significantly decreased after the VCUG (P<0.05). In group 2, the confusion and pain were increased after VCUG (P<0.05). Conclusion : It showed that doctor's explanation on the procedure in advance may raise the perception of pain and the possibility of refusal by parents. But the STAI-X-I, worry, anxiety after VCUG were significantly decreased in group 1, while the confusion and pain were increased in group 2. Therefore we suggest that prior and sufficient explanation about invasive procedure like VCUG can be helpful in ameliorating the anxiety of the parents.