• Radiation Oncology Journal
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• v.10 no.1
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• pp.7-14
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• 1992

Between August 1988 and December 1991, 24 patients with intracranial tumors were treated with stereotactic radiosurgery(RS) using a 10 MV linear accelerator at Severance Hospital, Yonsei University College of Medicine. There were 5 meningiomas, 3 craniopharyngiomas, 9 glial tumors, 2 solitary metastases, 2 acoustic neurinomas, 2 pineal tumors, and 1 non-Hodgkin's lymphoma. Ten patients were treated as primary treatment after diagnosis with stereotactic biopsy or neuroimaging study. Nine patients underwent RS for post-op. residual tumors and three patients as a salvage treatment for recurrence after external irradiation. Two patients received RS as a boost followed by fractionated conventional radiotherapy. Among sixteen patients who were followed more than 6 months with neuroimage, seven patients (2 meningiomas, 4 benign glial tumors, one non-Hodgkin's lymphoma) showed complete response on neuroimage after RS and nine patients showed decreased tumor size. There was no acute treatment related side reaction. Late complications include three patients with symptomatic peritumoral brain edema and one craniopharyngioma with optic chiasmal injury. Through this early experience, we conclude that stereotactically directed single high doses of irradiation to the small intracranial tumors is effective for tumor control. However, in order to define the role of radiosurgery in the management of intracraniai tumors, we should get the long-term results available to demonstrate the benefits versus potential complications of this therapeutic modality.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.287-293
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• 2010

Purpose: This study evaluated the effect of polishing techniques on surface roughness of polymethyl methacrylate (PMMA), as well as the influence of light-cured surface glaze and subsequent brushing on surface roughness. Materials and methods: A total of 60 PMMA specimens ($10{\times}10{\times}5\;mm$) were made and then divided into 6 groups of 10 each according to the polymerization methods (under pressure or atmosphere) and the surface polishing methods (mechanical or chemical polishing) including 2 control groups. The mechanical polishing was performed with the carbide denture bur, rubber points and then pumice and lathe wheel. The chemical polishing was performed by applying a light-cured surface glaze ($Plaquit^{(R)}$; Dreve-Dentamid GmbH). Accura $2000^{(R)}$, a non-contact, non-destructive, optical 3-dimensional surface analysis system, was used to measure the surface roughness (Ra) and 3-dimensional images were acquired. The surface roughness was again measured after ultrasonic tooth brushing in order to evaluate the influence of brushing on the surface roughness. The statistical analysis was performed with Mann-Whitney test and t-test using a 95% level of confidence. Results: The chemically polished group showed a statistically lower mean surface roughness in comparison to the mechanically polished group (P = .0045) and the specimens polymerized under the atmospheric pressure presented a more significant difference (P = .0138). After brushing, all of the groups, except the mechanically polished group, presented rougher surfaces and showed no statistically significant differences between groups. Conclusion: Although the surface roughness increased after brushing, the chemical polishing technique presented an improved surface condition in comparison to the mechanical polishing technique.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.183-188
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• 2012

Purpose: The concern of improving the quality of life and reducing side effects related to cancer treatment has been a subject of interest in recent years with advances in cancer treatment techniques and increasing survival time. This study is an analysis of differing scattered dose to the contralateral breast using common different treatment techniques. Materials and Methods: Eclipse 10.0 (Varian, USA) based $30^{\circ}$ EDW (Enhanced dynamic wedge) plan, $15^{\circ}$ wedge plan, $30^{\circ}$ wedge plan, Open beam plan, FiF (field in field) plan were established using CT image of breast phantom which in our hospital. Each treatment plan were designed to exposure 400 cGy using CL-6EX (VARIAN, USA) and we measured scattered dose at 1 cm, 3 cm, 5 cm, 9 cm away from medial side of the phantom at 1 cm depth using ionization chamber (FC 65G, IBA). We carried out measurement by separating effect of medial tangential field and lateral tangential field and analyze. Results: The evaluation of scattered dose to contralateral breast, $30^{\circ}$ EDW plan, $15^{\circ}$ wedge plan, $30^{\circ}$ wedge plan, Open beam plan, FIF plan showed 6.55%, 4.72%, 2.79%, 2.33%, 1.87% about prescription dose of each treatment plan. The result of scattered dose measurement by separating effect of medial tangential field and lateral tangential field results were 4.94%, 3.33%, 1.55%, 1.17%, 0.77% about prescription dose at medial tangential field and 1.61%, 1.40%, 1.24%, 1.16%, 1.10% at lateral tangential field along with measured distance. Conclusion: In our experiment, FiF treatment technique generates minimum of scattered dose to contralateral breast which come from mainly phantom scatter factor. Whereas $30^{\circ}$ wedge plan generates maximum of scattered doses to contralateral breast and 3.3% of them was scattered from gantry head. The description of treatment planning system showed a loss of precision for a relatively low scatter dose region. Scattered dose out of Treatment radiation field is relatively lower than prescription dose but, in decision of radiation therapy, it cannot be ignored that doses to contralateral breast are related with probability of secondary cancer.

• Journal of Oral Medicine and Pain
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• v.31 no.2
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• pp.185-197
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• 2006

The aim of this study was to investigate the beneficial effect of a daily dose of 300 mg of ASU taken for more than 3 months on the subjects diagnosed as osteoarthritis of temporomandibular joint by RDC/TMD. Total 68 outpatients(15-54y) of female except menopause in Orofacial Pain Clinics of the Pusan National University Hospital were randomly assigned to either an ASU group(n=36) or a placebo group(n=32). The pain, noise and limited mouth opening(LOM) were evaluated by numerical analogue scale(NAS, range 0-10) and maximum comfortable opening(MCO) were measured by milimeter scale. The difference of simple uptake rate(SUR) on bone scan, hot spot(HS) on coronal SPECT, condylar bony changes on CT between the ASU and placebo groups were compared to investigate the objective effect. The obtained results were as follows. 1. Comparison of the NAS of pain, noise, LOM and MCO before treatment and 3, 6 and 9 months after treatment showed no significant difference between the ASU and placebo groups. 2. Comparison of the NAS of pain, noise, LOM and MCO before treatment and 3, 6 and 9 months after treatment showed no significant difference between the ASU and placebo groups without splint treatment, but showed more increased MCO in the ASU group than the placebo group with splint treatment at 6, 9 months after treatment. 3. Comparison of the NAS of pain before treatment and 3, 6 and 9 months after treatment that the NAS of pain at first visit divided into two groups(above or below 6) showed more decreased the NAS of pain in the ASU group than the placebo group that the NAS of pain at first visit was above 6. 4. Comparison of the NAS of pain, noise, LOM and MCO during 6 months period showed improvement of clinical symptoms within group, but no significant difference between subjects. 5. The simple uptake ratio(SUR) on bone scan and hot spot(HS) on coronal SPECT showed more increased SUR and HS in affected side than non-affected side of the ASU and placebo groups. 6. Comparing of condylar bony changes, osseous remodeling were observed highest, osteophyte lowest in the affected and non-affected side of the two groups. After treatment, comparison of condylar bony changes were observed more decreased erosive features in the ASU group than the placebo group.

• Progress in Medical Physics
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• v.26 no.3
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• pp.143-152
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• 2015

In this study, we aim to design the architecture of the kV imaging system for tumor tracking in the dual-head gantry system and analyze its accuracy by simulations. We established mathematical formulas and algorithms to track the tumor position with the two-pair kV imaging systems when they are in the non-orthogonal positions. The algorithms have been designed in the homogeneous coordinate framework and the position of the source and the detector coordinates are used to estimate the tumor position. 4D XCAT (4D extended cardiac-torso) software was used in the simulation to identify the influence of the angle between the two-pair kV imaging systems and the resolution of the detectors to the accuracy in the position estimation. A metal marker fiducial has been inserted in a numerical human phantom of XCAT and the kV projections were acquired at various angles and resolutions using CT projection software of the XCAT. As a result, a positional accuracy of less than about 1mm was achieved when the resolution of the detector is higher than 1.5 mm/pixel and the angle between the kV imaging systems is approximately between $90^{\circ}$ and $50^{\circ}$. When the resolution is lower than 1.5 mm/pixel, the positional errors were higher than 1mm and the error fluctuation by the angles was greater. The resolution of the detector was critical in the positional accuracy for the tumor tracking and determines the range for the acceptable angle range between the kV imaging systems. Also, we found that the positional accuracy analysis method using XCAT developed in this study is highly useful and will be a invaluable tool for further refined design of the kV imaging systems for tumor tracking systems.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.53-61
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• 2005

Background : Cardiac troponin I (cTnI) is a specific marker of myocardial injury. It is known that a higher level of cTnI is associated with a poor clinical outcome in patients with acute coronary syndrome. An elevation in cTnI is also observed in various noncardiac critical illnesses. This study evaluated whether cTnI is useful for predicting the prognosis in noncardiac critically ill patients. Methods : From June 2003 to July 2004 at Gyeongsang National University Hospital, we enrolled 215 patients (male:142, female:73, mean age:$63{\pm}15$ years ) who were admitted for critical illness other than acute coronary syndrome at the medical intensive care unit(ICU). The severity score of critical illness (SAPS II and SOFA) was determined and serum cTnI level was measured within 24 hours after admission to the ICU. The mortality rate was compared between the cTnI-positive (${\geq}0.1{\mu}g/L$) and cTnI-negative ($cTnI<0.1{\mu}g/L$) patients at the $10^{th}$ and $30^{th}$ day after admission to the ICU. The mean cTnI value was compared between the survivors and non-survivors at the $10^{th}$ and $30^{th}$ day after admission to the ICU in the cTnI-positive patients. The correlation between cTnI and the severity of the critical illness score (SAPS II and SOFA) was also analyzed in cTnI-positive patients. Results : 1) The number of cTnI-negative and positive patients were 95(44%) and 120(56%), respectively. 2) The mortality rate at the $10^{th}$ and $30^{th}$ day after admission to the ICU was significantly higher in the cTnI-positive patients (29%, 41%) than in the cTnI-negative patients (12%, 21%)(p<0.01). 3) In the cTnI-positive patients, the mean value of the cTnI at the $10^{th}$ and $30^{th}$ day after admission to the ICU was significantly higher in the non-survivors ($4.5{\pm}9.2{\mu}g/L$, $3.5{\pm}7.9{\mu}g/L$) than in the survivors($1.8{\pm}3.6{\mu}g/L$, $2.0{\pm}3.9{\mu}g/L$) (p < 0.05). 4) In the cTnI-positive patients, the cTnI level was significantly correlated with the SAPS II score (r=0.24, p<0.001) and SOFA score (r=0.30, p<0.001). Conclusion : The cTnI may be a useful prognostic marker in noncardiac critically ill patients.

• Tuberculosis and Respiratory Diseases
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• v.59 no.6
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• pp.656-663
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• 2005

Background : The B-type natriuretic peptide (BNP) is a cardiac neurohormone that is specifically secreted from the ventricles in response to volume expansion and a pressure overload. Differentiating congestive heart failure from the pulmonary causes of dyspnea is very important for patients presenting with acute dyspnea. Methods : A retrospective study was carried out on 261 patients who were admitted to the emergency department of Hanyang University Hospital due to acute dyspnea from March to July 2004. The serum BNP levels of the patients were measured using the ELISA method. Results : The BNP levels were 382, 111-1140 pg/ml (median, interquartile range) in the heart failure group (n=119) and 29, 7-81 pg/ml in the non-heart failure group (n=142). The BNP levels according to the subgroups of heart failure were 820, 354-1620 pg/ml, 1650, 239-1990 pg/ml, and 378, 106-1120 pg/ml for the chronic obstructive pulmonary disease (COPD) with combined left heart failure (n=5), cor pulmonale (n=3), and left heart failure groups (n=111), respectively. The BNP levels according to the subgroups of non-heart failure were 39, 21-101 pg/ml, 59, 10-129 pg/ml, and 15, 6-47 pg/ml for the COPD (n=20), other pulmonary diseases (n=56), and other causes groups (n=66), respectively. The BNP levels were significantly different according to the underlying etiology (p<0.001), and were significantly higher in the COPD patients with left heart failure than in those without (p=0.002). When the patients with no cardiovascular risk factor such as diabetes mellitus, hypertension, smoking or renal failure were analyzed, the BNP levels were also significantly higher in the patients with heart failure than in those without(p<0.001). When 133 pg/ml was designated as the BNP cut-off level the sensitivity for predicting heart failure was 73 percent and the specificity was 87 percent. Conclusion : BNP measurements are useful for determining the presence of heart failure in the patients presenting with acute dyspnea. The possibility of heart failure must be seriously considered in patients with high BNP levels even when they have a pre-existing pulmonary disease such as COPD or no risk factors for heart failure.

• Tuberculosis and Respiratory Diseases
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• v.67 no.1
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• pp.21-26
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• 2009

Background: Non-invasive positive pressure ventilation (NPPV) ensures adequate gas exchange during bronchoscopy in spontaneously breathing, hypoxemic patients, thus avoiding endotracheal intubation. However, in some patients, endotracheal intubation is eventually required after bronchoscopy. This study investigated the incidence of intubation and predictors of a need for emergency intubation prior to NPPV bronchoscopy initiation. Methods: On a retrospective basis, we reviewed the medical records of 36 patients (median age, 55 years; interquartile range [IQR], 43~65 years) with acute hypoxemic respiratory failure who required NPPV during bronchoscopy between January 2005 and October 2007. Results: All patients were hypoxemic (median $PaO_2/FiO_2$ ratio 155; IQR 90~190), but tolerated bronchoscopy with NPPV support. SOFA score and SAPS II score immediately before NPPV initiation were 4 (3~7) and 36 (30~42), respectively. Seventeen (47%) patients needed endotracheal intubation at a median time of 22 (2~50) hours after bronchoscopy. Patients who needed intubation after bronchoscopy had a higher in-hospital mortality (11 [65%] vs. 4 [21%], p=0.017). Upon multiple logistic regression analysis, the need for intubation after bronchoscopy was independently associated with a $P_aO_2/FiO_2$ ratio (OR, 0.961; 95% CI, 0.924~0.999; p=0.047) immediately before NPPV initiation for bronchoscopy. Conclusion: The severity of the hypoxemia immediately prior to NPPV initiation for bronchoscopy was associated with the need for intubation after bronchoscopy in patients with hypoxemic respiratory failure.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.65-72
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• 2008

Pulse oximeter to monitor oxygen saturation during pediatric dental sedations enables early detection of hypoxemia. The purpose of this study was to monitor the hemoglobin oxygen saturation level and pulse rate of nonmedicated pediatric patients during routine restorative procedures to study the effect of procedure and treated jaw. We obtained data from 53 children treated at the Department of Pediatric Dentistry, Chonbuk national university hospital. Pulse rate and oxygen saturation were measured and recorded using pulse oximetry at each step of treatment. The results are as follows: 1. In non-anesthesia group, steep increase of pulse rate was observed during rubber dam application in the maxilla and during cavity preparation in the mandible. 2. In anesthesia group, pulse rate started to decrease after the rubber dam application in the maxilla, while its decrease observed since cavity preparation step in the mandible. 3. In non-anesthesia group, oxygen saturation level was relatively constant during all steps in the maxilla, but in mandible, it was higher during operation compared to its pre and post operation baseline. 4. In anesthesia group, oxygen saturation level was observed at 99% level through all steps in both jaw groups, and there was no statistical significance between the maxilla and the mandible groups(p>0.05). The purpose of this study was to evaluate the effect of routine dental treatment on the pulse rate and oxygen saturation level in nonmedicated pediatric patients during routine restorative procedures in the maxilla and mandible.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.53-58
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• 2013

Purpose: To optimize correction method for SPECT/CT, image quality consisting of resolution and contrast was evaluated using three radioisotopes ($^{99m}Tc$, $^{201}Tl$ and $^{131}I$) and three different correction methods; attenuation correction (AC), scatter correction (SC) and both attenuation and scatter correction (ACSC). Materials and Methods: Images were acquired with a SPECT/CT scanner and a conventional CT protocol with an OESM reconstruction algorithm (2 iterations and 10 subsets). For resolution measurement, fixed radioactivity (2.22 kBq) was infused into a spatial resolution phantom and full width at half maximum (FWHM) was measured using a vendor-provided software. For contrast evaluation, radioactive source with a ratio of 1:8 to background was filled in a Flanged Jaszczak phantom and percent contrast (%) were calculated. All the parameters for image quality were compared with non-correction (NC) method. Results: As compared with NC, image resolution of all three isotopes were significantly improved by AC and ACSC, not by SC. In particular, ACSC showed better resolution than AC alone for $^{99m}Tc$ and $^{201}Tl$. Image contrast of all three radioisotopes in a sphere with the largest diameter were enhanced by all correction methods. ACSC showed the highest contrast in all three radioisotopes, which was the most accurate in $^{99m}Tc$ (85.9%). Conclusion: Image quality of SPECT/CT was improved in all the radioisotopes by CT-based attenuation correction methods, except SC alone. SC failed to improve resolution in any radioisotopes, but it was effective in contrast enhancement. ACSC would be the best correction method as it improved resolution in radioisotopes with low energy levels and contrast in radioisotope with low energy levels. However, in radioisotope with high energy level, AC would be better than ACSC for resolution improvement.