• Journal of the Korean Arthroscopy Society
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• v.16 no.2
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• pp.160-166
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• 2012

Purpose: The aim of this study was to determine the patterns of the stress distribution within the reconstructed anterior cruciate ligament (ACL) double bundles in response to an anterior tibial load and rotatory load at $45^{\circ}$ flexed knee model by use of a 3-dimensional finite element analysis (FEM). Materials and Methods: The $0^{\circ}$ and $45^{\circ}$ flexed 3-D knee model were reconstructed based on the high resolution computed tomography (CT) images from the right knee of a healthy male subject. To simulate double bundle ACL reconstruction, in $0^{\circ}$ analytic model, four 7 mm diameter tunnels were created at the center of each anteromedial (AM) and posterolateral (PL) footprints on the femur and tibia. The grafts were inserted into the corresponding bone tunnels and then reconstructed knee model was flexed to $45^{\circ}$. As a next step, the 5 mm anterior tibial load and internal rotational load of $10^{\circ}$ were applied on the final Computer aided design (CAD) model. And then stress patterns of each bundle were assessed using a finite element analysis. Results: In response to the 5 mm of anterior tibial load, the AM bundle showed increased stresses around the tibial and femoral attachment sites; especially in the anterior aspect of the bundle. In the PL bundle, the highest stress concentration was also noticed on the anterior aspect of the bundle. Under $10^{\circ}$ internal rotational load, the stress concentration was predominant around the anterior aspect of the tibial attachment site within the AM bundle. The PL bundle also showed highest stress concentration on the anterior aspect of the bundle. Conclusion: Although the stress patterns were not identical among the AM and PL bundle, there were common trends in the stress distribution. The stress concentration was predominant on the anterior aspect of both bundles in response to the anterior tibial load and rotatory load.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.378-388
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• 2001

Purpose: In this study, we developed a new method for the determination of renal depth with anterior and posterior renal scintigrams in a dual-head gamma camera, considering the attenuation factor $e^{-{\mu}x}$ of the conjugate-view method. Material and Method: We developed abdomen and kidney phantoms to perform experiments using Technetium-99m dimercaptosuccinic acid ($^{99m}Tc$-DMSA). The phantom images were obtained by dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators (ICONf, Siemens). The equation was derived from the linear integration of omission ${\gamma}$-ray considering attenuation from the posterior abdomen to the anterior abdomen phantom surface. The program for measurement was developed by Microsoft Visual C++ 6.0. Results : Renal depths of the phantoms were derived from the derived equations and compared with the exact geometrical values. Differences between the measured and the calculated values were the range of 0.1 to 0.7 cm ($0.029{\pm}0.15cm,\;mean{\pm}S.D.$). Conclusion: The present study showed that the use of the derived equations for renal depth measurements, combined with quantitative planar imaging using dual-head gamma camera, could provide more accurate results for individual variation than the conventional method.

• Tuberculosis and Respiratory Diseases
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• v.46 no.1
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• pp.65-74
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• 1999

Background : Open lung biopsy(OLB) has conventionally been regarded as the gold standard for the diagnosis in interstitial lung disease. With recent advances in diagnostic technique such as high resolution computed tomography(HRCT), and transbronchial lung biopsy(TBLB) which provide relatively accurate diagnosis of ILD, it is necessary to reevaluate the role of these methods in the diagnosis of ILD. Methods: We carried out a retrospective analysis of nineteen patients who underwent OLB at Dankook University Hospital for the diagnosis of acute and chronic ILD, between May 1995 and June 1998. By reviewing the medical records, the demographic findings, underlying conditions, HRCT and TBLB findings, OLB diagnosis, therapy after OLB, and complication of OLB were evaluated. Results: Thirteen patients(68.4%) had chronic ILD(symptom duration over 2 weeks prior to OLB), and six patients(31.6%) had acute ILD(symptom duration less than 2 weeks). Specific diagnosis were reached in 92%(12/13) of chronic ILD(5 bronchiolitis obliterans organizing pneumonia(BOOP), 2 constrictive bronchiolitis, 3 usual interstitial pneumonia, 1 hypersensitivity pneumonitis, 1 eosinophilic pneumonia), and in all patients of acute ILD(5 acute interstitial pneumonia, 1 pneumocystis carinii pneumonia). HRCT were performed in all patients and a correct first choice diagnosis rate of HRCT was 42%(5/12) in chronic ILD. In chronic ILD patients, 62%(8/13) received specific therapy(steroid therapy in 7 patients and moving in one patient), after OLB, but in acute ILD, all patients received specific therapy(steroid therapy in 5 patients and steroid and antibiotic therapy in one patient) after OLB. The in-hospital mortality after OLB was 5.3%(1/19). Conclusion: OLB is an excellent diagnostic technique with relatively low complications in patients with ILD. Therefore OLB should be considered in patients with ILD when the specific diagnosis is important for the treatment, especially in patients with acute ILD.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.271-278
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• 2012

Purpose: Recently implant surgical guides were used for accurate and atraumatic operation. In this study, the accuracy of two different types of surgical guides, positioning device fabricated and stereolithography fabricated surgical guides, were evaluated in four different types of tooth loss models. Materials and methods: Surgical guides were fabricated with stereolithography and positioning device respectively. Implants were placed on 40 models using the two different types of surgical guides. The fitness of the surgical guides was evaluated by measuring the gap between the surgical guide and the model. The accuracy of surgical guide was evaluated on a pre- and post-surgical CT image fusion. Results: The gap between the surgical guide and the model was $1.4{\pm}0.3mm$ and $0.4{\pm}0.3mm$ for the stereolithography and positioning device surgical guide, respectively. The stereolithography showed mesiodistal angular deviation of $3.9{\pm}1.6^{\circ}$, buccolingual angular deviation of $2.7{\pm}1.5^{\circ}$ and vertical deviation of $1.9{\pm}0.9mm$, whereas the positioning device showed mesiodistal angular deviation of $0.7{\pm}0.3^{\circ}$, buccolingual angular deviation of $0.3{\pm}0.2^{\circ}$ and vertical deviation of $0.4{\pm}0.2mm$. The differences were statistically significant between the two groups (P<.05). Conclusion: The laboratory fabricated surgical guides using a positioning device allow implant placement more accurately than the stereolithography surgical guides in dental clinic.

• Tuberculosis and Respiratory Diseases
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• v.60 no.6
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• pp.625-630
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• 2006

Background: Pulmonary hypertension in COPD patients is the result of a direct effect of tobacco smoke on the intrapulmonary vessels with the abnormal production of the mediators that control vasoconstriction, vasodilatation, and vascular cell proliferation, which ultimately lead to aberrant vascular remodeling and physiology. COPD patients are prone to the developmint of an acute and chronic thromboembolism with an elevation of the plasma procoagulant and fibrinolytic markers However, the roles of the coagulation and fibrinolysis system on the right ventricular dysfunction in COPD patients are not well defined. We examined the alteration of the coagulation and fibrinolysis system in COPD patients according to the right ventricular function measured using cardiac multidetector computed tomography (MDCT). Methods: The right ventricular ejection fraction (RVEF) was measured using cardiac MDCT in 26 patients who were diagnosed with COPD according to the definition of the GOLD guideline. The plasma level of thrombin antithrombin (TAT) and plasminogen activator inhibitor (PAI)-1 were measured using an enzyme linked immunoassay. Results: The plasma TAT was markedly elevated in COPD patients ($10.5{\pm}19.8{\mu}g/L$) compared with those of the control ($3.4{\pm}2.5{\mu}g/L$) (p<0.01). However, the plasma PAI-1 in COPD patients ($29.6{\pm}20.7ng/mL$) was similar to that in the controls. The plasma TAT showed a significant inverse relationship with the RVEF measured by the cardiac MDCT in COPD patients (r=-0.645, p<0.01). However, the plasma PAI-1 did not show a relationship with the RVEF (r=0.022, p=0.92). Conclusion: These results suggest that the coagulation system in COPD patients is markedly activated, and that the plasma level of TAT might be a marker of a right ventricular dysfunction in COPD patients.

• Tuberculosis and Respiratory Diseases
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• v.58 no.6
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• pp.576-581
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• 2005

Background : Thoracic actinomycosis is a relatively uncommon anaerobic infection caused by Actinomyces israelii. There have been only a few case reports of endobronchial actinomycosis. The aim of this study was to evaluate the clinical manifestation and treatment of endobronchial actinomycosis. Material and Methods : Seven patients with endobronchial actinomycosis, who were diagnosed in the past 10 years, were retrospectively reviewed. Results : Cough and sputum were the most common symptoms. The chest radiograph and computed tomography showed necrotic consolidation (n=3), atelectasis (n=2), mass (n=1) and an endobronchial nodule (n=1). Proximal broncholithiasis was observed in five patients. All cases were initially suspected to have either lung cancer or tuberculosis. In these patients, the median duration of intravenous antibiotics was 3 days (range 0-12 days) and the median duration of oral antibiotics was 147 days (range 20-412 days). Two patients received oral antibiotic therapy only. There was no clinical evidence of a recurrence. Conclusion : Endobronchial actinomycosis frequently manifests as a proximal obstructive calcified endobronchial nodule that is associated with distal post-obstructive pneumonia. The possibility of endobronchial actinomycosis is suggested when findings of broncholithiasis are present at chest CT. The traditional recommendation of 2-6 weeks of intravenous antibiotics and 6-12 months of oral antibiotic therapy are not necessarily essential in all cases of endobronchial actinomycosis.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.65-71
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• 2018

Purpose : Standardized pillow may not support patient's individual cervical spine thoroughly when head and neck radiation therapy with $Tomotherapy^{(R)}$. Therefore, the purpose of this study was to make a comparative analysis for the difference of using standardized pillow only and using customized cervical spine immobilizer with standardized pillow. Materials and Methos : The head and neck cancer patients who are treated image-guided radiation therapy(IGRT) with $Tomotherapy^{(R)}$ were divided into two groups, 20 patients using standardized pillow only, and 20 patients using customized cervical spine immobilizer with standardized pillow. We achieved 20 mega-voltage computed tomography(MVCT) image per patient, compared curvature of the cervical spine in MVCT with curvature of the cervical spine in CT-simulation. Results : Results of comparative analysis were curvature consistency 95.9 %, maximum error of distance 41.9 mm, average distance error per fractionation 19.4 mm, average standard deviation 1.34 mm in case of using standardized pillow only, curvature consistency 98.9 %, maximum error of distance 12.9 mm, average distance error per fractionation 5.8 mm, average standard deviation 0.59 mm in case of using customized cervical spine immobilizer with standardized pillow. Conclusion : Using customized cervical spine immobilizer shows higher reproducibility and low distance error, therefore customized cervical spine immobilizer could be useful for head and neck cancer patients who need radiation therapy.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.127-137
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• 2022

Purpose To assess the prevalence of incidentally detected lumbar spondylolysis in children. Materials and Methods We retrospectively reviewed the data of 809 patients under the age of 11 years (mean age, 7.0 ± 2.7 years; boys:girls = 479:330) who underwent abdominal and pelvic CT between March 2014 and December 2018. We recorded the presence, level, and laterality (unilateral or bilateral) of spondylolysis. Patients were divided into two groups based on the presence of spondylolysis: the spondylolysis (SP) and non-SP groups. Results In total, 21 cases of spondylolysis were detected in 20 patients (20/809, 2.5%). The mean age of the SP group was higher than that of the non-SP group (7.8 ± 1.8 vs. 6.9 ± 2.7 years, p > 0.05). The prevalence of spondylolysis in boys was higher than that in girls (15/479 [3.1%] vs. 5/330 [1.5%], p > 0.05). The prevalence of spondylolysis in school-age children (6-10 year olds) was higher than that in preschool-age children (0-5 year olds) (17/538 [3.2%] vs. 3/271 [1.1%], p > 0.05). L5 was the most common level of spondylolysis (76.2%); one 8-year-old boy had two-level spondylolysis. One case of isthmic spondylolisthesis was detected in a 10-year-old boy (1/809, 0.1%). There were 11 unilateral spondylolysis cases (11/21, 52.4%). Conclusion In our study, the prevalence of spondylolysis in children under the age of 11 was 2.5%. The prevalence was higher in boys than in girls and in school-age than in preschool-age children, despite the lack of any statistically significant differences.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.37-48
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• 2017

Purpose: The most basic conditions of radiation therapy is to prevent unnecessary exposure of normal tissue. The risk factors that are important o evaluate the dose emitted to the lung and heart from radiation therapy for breast cancer. Therefore, comparing the dose factors of a normal tissue according to the radion treatment position and Seeking an effective radiation treatment for breast cancer through the analysis of the correlation relationship. Materials and Methods: Computed tomography was conducted among 30 patients with left breast cancer in supine and prone position. Eclipse Treatment Planning System (Ver.11) was established by computerized treatment planning. Using the DVH compared the incident dose to normal tissue by position. Based on the result, Using the SPSS (ver.18) analyzed the dose in each normal tissue factors and Through the correlation analysis between variables, independent sample test examined the association. Finally The HI, CI value were compared Using the MIRADA RTx (ver. ad 1.6) in the supine, prone position Results: The results of computerized treatment planning of breast cancer in the supine position were V20, $16.5{\pm}2.6%$ and V30, $13.8{\pm}2.2%$ and Mean dose, $779.1{\pm}135.9cGy$ (absolute value). In the prone position it showed in the order $3.1{\pm}2.2%$, $1.8{\pm}1.7%$, $241.4{\pm}138.3cGy$. The prone position showed overall a lower dose. The average radiation dose 537.7 cGy less was exposured. In the case of heart, it showed that V30, $8.1{\pm}2.6%$ and $5.1{\pm}2.5%$, Mean dose, $594.9{\pm}225.3$ and $408{\pm}183.6cGy$ in the order supine, prone position. Results of statistical analysis, Cronbach's Alpha value of reliability analysis index is 0.563. The results of the correlation analysis between variables, position and dose factors of lung is about 0.89 or more, Which means a high correlation. For the heart, on the other hand it is less correlated to V30 (0.488), mean dose (0.418). Finally The results of independent samples t-test, position and dose factors of lung and heart were significantly higher in both the confidence level of 99 %. Conclusion: Radiation therapy is currently being developed state-of-the-art linear accelerator and a variety of treatment plan technology. The basic premise of the development think normal tissue protection around PTV. Of course, if you treat a breast cancer patient is in the prone position it take a lot of time and reproducibility of set-up problems. Nevertheless, As shown in the experiment results it is possible to reduce the dose to enter the lungs and the heart from the prone position. In conclusion, if a sufficient treatment time in the prone position and place correct confirmation will be more effective when the radiation treatment to patient.