• Progress in Medical Physics
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• v.20 no.1
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• pp.43-50
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• 2009

The 4 bank mico-MLC (mMLC; Acculeaf, Direx, Isral) has been commissioned for clinical use of linac based stereotactic radiosurgery. The geometrical parameters to control the leaves were determined and comparisons between measured and calculated by the calculation model were performed in terms of absolute dose (cGy/100 MU). As a result of evaluating calculated dose for various field sizes and depths of 5 and 10 cm in water in the geometric condition of fixed SSD (source to surface distance) and fixed SCD (source to chamber distance), most of differences were within 1% for 6 MV and 15 MV x-rays. The penumbral widths at the isocenter were approximately evaluated to 0.29~0.43 cm depending on the field size for 6 MV and 0.36~0.51 cm for 15 MV x-rays. The average transmission and leakage for 6 MV and 15 MV x-rays were 6.6% and 7.4% respectively in single level of leaves fully closed. In case of dual level of leaves fully closed the measured transmission is approximately 0.5% for both 6 MV and 15 MV x-rays. Through the commissiong procedure we could verify the dose characteristics of mMLC and approximately evaluate the error ranges for treatment planning system.

• Tuberculosis and Respiratory Diseases
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• v.39 no.1
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• pp.55-61
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• 1992

Background: The lung is the most common site of metastasis and usually it manifests as a single or multiple nodules in chest X-ray. But less commonly the cancer spreads through the lymphatics and X-ray shows diffuse reticulonodular densities. Sometimes, patient is presented with respiratory symptoms only with interstitial lung infiltration before the signs of primary tumor and in that cases, the differential diagnosis with other interstitial lung disease is required. We have experienced 5 such cases, who were diagnosed as lymphangitic carcinomatosis by transbronchial lung biopsy. Methods: Clinical manifestation, pulmonary function test, modified thin section CT, bronchoalveolar lavage and transbronchial lung biopsy were done. Results: The primary tumor was gastric cancer in 3, lung cancer in 2. Pulmonary function test showed restrictive pattern with low DLco in 2 patients and obstructive pattern in one. Bronchoalveolar lavage showed lymphocytosis in 4 patients and malignant cells were found in one patient. Transbronchial lung biopsy revealed malignant cells localized to the lymphatics (peribronchial, perivascular and perialveolar). Cell type was adenocarcinoma in 4 and squamous cell carcinoma in one. Conclusion: Rarely lymphangitic carcinomatosis can be presented as diffuse interstitial lung disease and easily diagnosed by transbronchial lung biopsy.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.709-717
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• 1999

Background & Method : Bronchiolitis obliterans organizing pneumonia(BOOP) is a specific clinicopathologic condition characterized by chronic inflammatory interstitial infiltrates. Cryptogenic form of BOOP presents subacute clinical course of flu-like illness, such as cough, fever, dyspnea with exertion and other constitutional symptoms. Pathologically it shows the presence of granulation tissue filling the lumen of terminal and respiratory bronchioles, extending into distal airspaces. Recently, we reviewed 24 cases of idiopathic type of BOOP, 5 cases of our hospital and another 19 cases on Korean literatures, and compared with reviewed data from foreign literatures. Results : Mean age was 54 years old and there was female preponderance in domestic reports. Their common presenting symptoms were dyspnea and cough, and mean duration of illness was 41 days. On chest examination, inspiratory crackle was a common finding. The laboratory findings were nonspecific except hypoxemia. Lung function studies revealed restrictive defect or combined obstructive and restrictive pattern in most patients. Bilateral patchy and nonsegmental alveolar opacities constituted characterized radiographic finding, highlighted on high resolution computed tomogram. It showed a favorable prognosis with an excellent responsiveness to corticosteroid therapy. The clinical features and laboratory findings were similar between domestic and foreign cases except female preponderance in Korean cases. Conclusion : If the clinical course is atypical or pregressive under proper treatment, clinicians should reevaluate clinical features and radiographic findings under the consideration of BOOP. Tissue confirmation would be recommended for the definitive diagnosis of BOOP.

• Progress in Medical Physics
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• v.15 no.1
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• pp.23-29
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• 2004

The relationship between the dose calculated with a radiotherapy treatment planning system (RTPS) and CT number verses the relative electron density curve was investigated for various CT voltages and beam qualifies. We obtained the relationship between the CT numbers and electron densities of the tissue equivalent materials for various CT voltages and beam qualifies. At lower CT voltages, the higher density materials, like cortical bone, showed larger CT numbers and the soft tissues showed no variations. We peformed a phantom study in a RTPS, where a phantom consisted of lung and bone legions in water. We calculated the dose received behind the lung and bone regions for 6 MV photon beams, in which the regions below the lung, water and bone received higher doses in this listed order. The result was the same for 10 MV photon beams. For the clinical application, the doses were calculated for the lung and pelvis. No difference was observed when using different electron density conversion tables with various CT voltages from a same CT. A relative dose difference of 1.5% was obtained when the CT machine for the density conversion table was different from that for the CT image for planning.

• The Korean Journal of Cytopathology
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• v.1 no.2
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• pp.152-157
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• 1990

A 70-year-old female who was diagnosed as myxoid chondrosarcoma by fine needle aspiration of a pleural mass is described. She presented with left chest discomfort of 4 months' duration and aggravating dyspnea and chest pain for 2 months. Chest X-ray and CT scan revealed a large lobulated low density mass invading chest wall at the left pleural cavity and massive pleural fluid. Fine needle aspiration was done under the impression of mesothelioma or metastatic cancer. The aspirates from the mass were very cellular and composed of isolated or clustered forms of large plump cells. Abundant cytoplasm was blulsh opaque and the margin was rounded in the isolated cells, whereas clustered cells show ill-defined ceil borders and aggregating tendency. The nuclei were eccentric, round to ovoid, and had fine chromatin pattern and multiple small nucleoli. Cellular pleomorphism or mitotic figure was not definite. These findings were consistent with cytologic features of chondrosarcoma. Final diagnosis was confirmed as myxoid chondrosarcoma by mediastinoscopic biopsy and the tumor showed strong positivity for S-100 protein.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.583-595
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• 2006

Quartz veins from the Hwawon area are an epithermal quartz vein that is filling the fault zone within Precambrian metasedimentary rocks and Jurassic granite. Mineralization can be divided into hypogene and supergene stages. Hypogene stage is associated with hydrothermal alteration minerals(propylitic and argillic zones) such as epidote, chlorite, illite, sericite and sulfides such as pyrite, sphalerite, chalcopyrite, galena, bornite, cubanite, argentian tetrahedrite, Pb-Ag-S system and Pb-Te-S system. Supergene stage is composed of Fe-Mn oxide, Zn-Fe oxide and Pb oxide. Fluid inclusion data indicate that homogenization temperatures and salinity of hypogene stage range from $291.2^{\circ}C$ to $397.3^{\circ}C$ and from 0.0 to 9.3 wt.% eq. NaCl, respectively. It suggests that ore forming fluids were cooled and diluted with the mixing of meteoric water. Oxygen($-0.7{\sim}3.5%_{\circ}$(white quartz: $-0.7{\sim}3.5%_{\circ}$, transparent quartz: $2.4%_{\circ}$)) and hydrogen($-70{\sim}55%_{\circ}$(white quartz: $-70{\sim}55%_{\circ}$, transparent quartz: $-62%_{\circ}$)) isotopic composition indicates that hydrothermal fluids were derived from magmatic and evolved by mixing with meteoric water during mineralization.

• Radiation Oncology Journal
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• v.4 no.1
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• pp.55-62
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• 1986

From Nov. 1983 through Jan. 1986, 43 patients with nonsmall cell lung cancer were treated by radiation therapy at Inje Medical College Paik Hospital. 38 patients were available for the analysis of this study. 33 patients received definite irradiation with curative intent, while 5 patients received postoperative irradiation. Chemotherapy was added in 12 patients before, during and after radio-therapy. 28 patients were squamous cell carcinoma and 10 patients were adenocarcinoma. There were 29 men and 9 women (median age, 50 years; range 34 to 74 years). Stage 1 was 1 patient, Stage 11,7 patient, and Stage 111,30 patients. Among 33 patients who received radiotherapy with curative intent, follow up radiological study revealed complete response in 12 patients $(36\%)$, partial response, in 9 patients $(27\%)$, and minimal response, in 5 patients $(15\%)$, while 7 patients $(21\%)$ were nonresponders. Median survival for all patients was 6.9 months; squamous cell carcinoma, 7.3 months, adenocarcinoma, 5.9 months. Responders survived median 7 months, while nonresponders survived median 1.9 months. Improved complete response rate and survival were shown in high radiation dose group. As prognostic factors, age, initial performance status, sex, histology and tumor location were evaluated.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.506-512
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• 2010

Background: This study was designed to evaluate the FDG uptake ratio of mediastinal node and primary tumors using integrated PET/CT imaging combined with Glut-1 expression of the primary tumor in order to predict the N2 status more accurately in NSCLC patients. Material and Method: Patients who underwent integrated PET/CT scanning with a detectable mSUV for both primary tumors and mediastinal lymph nodes were eligible for this study. The FDG uptake ratio between the mediastinal node and the primary tumor was calculated. Result: The average mSUV of primary tumors and mediastinal nodes were, respectively, $7.4{\pm}2.2$ and $4.2{\pm}2.2$ in N2-positive patients and $7.6{\pm}3.7$ and $2.8{\pm}6.9$ in N2-negative patients. The mean FDG uptake ratio of mediastinal node to primary tumor were $0.58{\pm}0.23$ for malignant N2 lymph nodes and $0.45{\pm}0.20$ for benign lymph nodes (p<0.05). Models which combined Glut-1 expression with an FDG ratio have better diagnostic power than models that use the FDG uptake ratio alone. Conclusion: In some patients with a previous history of pulmonary tuberculosis or other inflammatory lung diseases, an FDG uptake ratio combined with Glut-1 expression may be useful in diagnosing mediastinal node metastasis more exactly.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.221-229
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• 2006

Mineralogical and chemical examinations were performed on interstratified illite-smectite (I-S) minerals that occur in the mudstones from a petroleum exploration well in the Tertiary marine basin, Japan. X-ray diffraction analysis shows that component layers of illite in the interstratified I-S increase with increasing burial depth while those of smectie decrease. In addition, the randomly (R=0) interstratified illite-smectite is changed into Rp1 ordered I-S at a depth of about 4,000 m, which corresponds to the result of organic analysis and indicates a burial temperature of about $100^{\circ}C$. However, the present geothermal gradient shows that the conversion of the random I-S to R=0 ordered I-S is likely to occur at 3,000 m. This discrepancy may be interpreted by the reverse fault at 2,500 m which resulted in a deeper burial of sediments up to 1,000 m. Chemical analysis also shows the compositional variation in I-S with increasing depth: a decrease in Si and an increases in Al and K, indicating that the substitution of Al for Si in tetrahedral sheets is compensated by the addition of K to interlayers. K may be derived from K-feldspar and micas, which is present in the mudstones.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.169-178
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• 2020

The number of CT scans is increasing every year due to the improvement of the medical standards of the public, and thus the annual dose of medical radiation is also increasing. In this study, we evaluated the effective dose of the human body exposed to CT scans and estimated LAR. First, five region were selected from the CT diagnostic reference level guideline, and the effective dose of human body exposed to each examination was evaluated by clinical CT device. Second, the human organs and effective dose were calculated using the ALARA-CT program under the same conditions. Third, lifetime attributable risk (LAR) estimated by the effective dose exposed through the previous CT scan was estimated. As a result, the most effective dose was 21.18 mSv during the abdomen 4 phase scan, and the dose level was below DRL for all other tests except for the abdominal examination. As a result of evaluating effective dose using a dose calculation program under the same conditions, the results showed about 1.1 to 1.9 times higher results for each examination. In the case of organ dose, the closer the organ to the scan site, the higher the scattering ray. The lifetime attributable risk to CT radiation dose in adults was gradually decreased with age, and the results were somewhat different according to gender.