• Korean Journal of Digital Imaging in Medicine
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• v.9 no.2
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• pp.31-38
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• 2007

To evaluate the accuracy and extent in the localization of cerebral motor coutex activation using a gradient- echo echo planar imaging(GE-EPI) compared to spin-echo echo planar iimaging(SE-EPI) on 3T MR imaging. Functional MR imaging of cerebral motor cortex activation was examined in GE-EPI and SE-EPI in five healthy male volunteers. A right finger movement was accomplished with a paradigm of 6 task and rest, periods and the cross-correlation was used for a statistical mapping algorithm. We evaluated any sorts of differenced of the time seried and the signal intensity changes between the rest and task periods obtained with two technoques. The qualitative analysis was distributed with activation sites of large veins and small veins by using two techniques and was found that both the techniques were clinically uesful for delineating large veins and small veins in fMRL Signal intensity charge of the rest and activation periods provided simmilar activations in both methods(GE-EPI : 0.93$\pm$0.11, SE-EPI : 0.80$\pm$.015) but the signal intensity in GE-EPI(133.95$\pm$15.76) was larger than in SE-EPI(74.5$\pm$18.90). The average SNRs of EPI raw data were higher at SMA in SE-EPI(48.54$\pm$12.37) than GE-EPI(41.4$\pm$12.54) and at M1 in SE-EPI(43.24$\pm$11.77) than GE-EPI(38.27$\pm$6.53). The localization of activation voxels of the GE-EPI showed a larger vein but the SE-EPI generally showed small vein. Then the analysis results of the two techniques were used for a statistacal paired student t-test. SE-EPI was found clinically useful for localizing the cerebral moter cortex cativation on 3.0T, but showed a little different activation patterns comparad to GE-EPI. In conclusion, SE-EPI may be feasible and can detect true cortical activation from capillaries and GE-EPI can obtain the large veins in the motor cortex activation on 3T MR imaging.

• Journal of Chest Surgery
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• v.32 no.4
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• pp.353-357
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• 1999

Background: Mitral valve replacement(MVR) with chordal preservation in patients with mitral vlavular disease has been proven to be beneficial for left ventricular function and for reduction of postoperative complication. Material and Method: From January 1995 to July 1996, the early postoperative results of mitral valve replacement were compared between 20 patients who underwent chordae resection(classic MVR group) and 10 patients who underwent chordae preservation(preservation MVR group) in the Department of Thoracic and Cardiovascular Surgery, Chunbuk National University Hospital. Result: There was no significant difference between the two groups in age, sex, NYHA functional class, cardiothoracic ratio, echocardiographic finding, cardiopulmonary bypass time and aortic cross clamping time. The difference between preoperative and postoperative cardiothoracic ratio after 3 months was not statistically significant. At echocardiographic left ventricular evaluation, ejection fraction and fractional shortening decreased slightly in the preservation group then preoperative value (p=0.47, p=0.12), however, decreased significantly in the classic MVR group(p=0.03, p=0.04), and were statistically significant between the two groups(p=0.03, p=0.02). Conclusion: We conclude that MVR with chorda preservation seems to have a beneficial effect on postoperative left ventricular performance in mitral valve disease than the classic MVR.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.561-565
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• 2009

Background: There haven't been any papers that have analyzed the recent trends in the changing attitudes and results of Korean thoracic and cardiovascular surgeons who submit scientific papers to the major cardiothoracic journals. Material and Method: I analyzed the original articles that were published in the major cardiothoracic surgery journals from 1995 to 2008 by Korean thoracic and cardiovascular surgeons. The data was retrieved from the internet websites of Pubmed, three major international SCI (Science Citation Index) journals and the Korean Journal of Thoracic and Cardiovascular Surgery. I then analyzed the data according to the chronological year, the subjects and the subspecialties. Result: The total number of original articles in the three international journals was 14,629. Among them, the number of articles written by Korean scientists was 157 (1.07%). A sharp increase was identified from 28 articles out of 7,674 articles (0.36%) prior to 2002, to 129 articles out of 6,955 articles (1.83%) after 2003. On the other hand, the annual number of articles in the Korean Journal was markedly decreased from 126.8 articles by 1999 to 80.0 articles after 2000. The annual number of articles in the Korean Journal was also decreased from 58.8% by 1999 to 48.3% after 2000. Conclusion: There was an observed increase in submitting articles to the international SCI journals after 2000 rather than to the Korean journal. The proportion of original articles in the Korean journal is also decreasing. I think we need to pay special attention to improve the quality and quantity of articles published in the Korean journal.

• Progress in Medical Physics
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• v.16 no.4
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• pp.176-182
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• 2005

Stereotactic radiosurgery (SRS) is a technique to deliver a high dose to a target region and a low dose to a critical organ through only one or a few irradiation. The SRS must be planned exactly. Currently the surgery plan is peformed by trial and error method. There are many questions about the reliability and reproducibility of the plan result. This study Improve each step of the Oh's method based on heuristic target shaping to obtain the better result. The target was reconstructed using cylinders with same height and the neighbored cylinders were combined according to the difference of each center and diameter. Then, spheres were packed within each cylinders by the packing rules. Two virtual targets were used to compare this method with Oh's method. As a result, the numbers of isocenter were successfully reduced - more than $35\%$ and $26\%$ - without serious differences of proscription isodose to tumour volume ratio (PITV) and maximum dose to proscription dose ratio (MDPD). This technique using cylinder piling and sphere packing will be a helpful tool to planner in stereotactic radiosurgery.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.591-599
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• 1996

This study was undertaken to investigate the cytotoxicity of orthodontic wires after doing various treatments to the wires. 018x025 inch Stainless steel(A) and Co-Cr(B) wires were used and each of them were divided into 4 groups. A-1 and B-1 groups were as received state, and A-2 and B-2 groups were heat treated. A-3 and B-3 groups were electropolished after heat treatment, and A-4 and B-4 groups were soldered with Ag-solder. Each group had 3 wires and these were sterilized with Ethylene Oxide gas. We used human gingival fibroblast cell culture and agar overlay technique to investigate the cytotoxicity of each group of wires. The cytotoxicity of wire was assessed using reaction index (zone index/lysis index). The findings of this study were as follows. 1. Both of the stainless steel wire and Co-Cr wire showed no cytotoxicity in as received state. 2. Heat treatment or electropolishing of the wires had no effect on the cytotoxicity of the wires 3. Soldered stainless steel wires showed a little wider zone of discoloration than soldered Co-Cr wires, but the zone index and cytotoxicity(reaction index) was not different. 4. Soldered wires showed moderate cytotoxicity in both of the wires.

• Progress in Medical Physics
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• v.18 no.2
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• pp.55-64
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• 2007

Our objective was to evaluate the clinical feasibility of spatial domain filtering as an alternative to additional image reconstruction using different kernels in CT. Kernels were grouped as H30 (head medium smooth), B30 (body medium smooth), S80 (special) and U95 (ultra sharp). Derived from thin coilimated source images, four sets of images were generated using phantom kernels. MTF (50%, 10%, 2%) measured with H30 (3.25, 5.68, 7.45 Ip/cm) B30 (3.84, 6.25, 7.72 Ip/cm), S80 (4.69, 9.49, 12.34 Ip/cm), and U95 (14.19, 20.31, 24.67 Ip/cm). Spatial resolution for the U95 kernel (0.6 mm) was 33.3% greater than that of the H30 and B30 (0.8 mm) kernels. Initially scanned kernels images were rated for subjective image qualify, using a five-point scale. Image scanned with a convolution kernel led to an increase in noise (U95), whereas the results for CT attenuation coefficient were comparable. CT images increase the diagnostic accuracy in head (H30), abdomen (B30), temporal bone and lung (U95) kernels may be controlled by adjusting CT various algorithms, which should be adjusted to take into account the kernels of the CT undergoing the examination.

• Progress in Medical Physics
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• v.18 no.4
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• pp.194-201
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• 2007

Although Gamma Knife irradiates much more radiation in a single session than conventional radiotherapy, there were only a few studies to measure absolute dose of a Gamma Knife. Especially, there is no report of application of International Atomic Energy Agency (IAEA) TRS-398 which requires to use a water phantom in radiation measurement to Gamma Knife. In this article, the authors reported results of the experiments to measure the absorbed dose to water of a Gamma Knife Model C using the IAEA TRS-398 protocol. The absorbed dose to water of a Gamma Knife model C was measured using a water phantom under conditions as close as possible to the IAEA TRS-398 protocol. The obtained results were compared with values measured using the plastic phantom provided by the Gamma Knife manufacturer. Two Capintec PR-05P mini-chambers and a PTW UNIDOS electrometer were used in measurements. The absorbed dose to water of a Gamma Knife model C inside the water phantom was 1.38% larger than that of the plastic phantom. The current protocol provided by the manufacturer has an intrinsic error stems from the fact that a plastic phantom is used instead of a water phantom. In conclusion, it is not possible to fully apply IAEA TRS-398 to measurement of absorbed dose of a Gamma Knife. Instead, it can be a practical choice to build a new protocol for Gamma Knife or to provide a conversion factor from a water phantom to the plastic phantom. The conversion factor can be obtained in one or two standard laboratories.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.400-409
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• 2020

This descriptive research study investigated the mediating effect of positive psychological capital (PPC) on the relationship between emotional labor (EL) and job satisfaction (JS) of clinical nurses. The data was collected from 274 nurses working for two hospitals in the D city, Korea, from 7 Sep. 2016 through 23 Sep. 2016. General characteristics, EL, JS, and PPC were surveyed using structured questionnaires. Statistical analysis was performed using descriptive statistics, ANOVA, and stepwise multiple regression analysis with SPSS/WIN 21.0. The mediating effect of PPC on the relationship between EL and JS was tested using Baron & Kenny's 3-step hierarchical regression analysis. There were negative correlations between EL and JS (r=-.36, p<.001) and EL and PPC (r=-.25, p<.001) and a positive correlation between JS and PPC (r=.47, p<.001). In addition, the PPC, had a partial mediating effect (z=-3.44, p=.001) on the relationship between EL and JS. It is proposed, based on the results, to develop an organized intervention program that enhances job satisfaction by reducing emotional labor and strengthening positive psychological capital in clinical nurses.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.565-570
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• 2016

Radioactive iodine($^{131}I$) treatment reduces recurrence and increases survival in patients with differentiated thyroid cancer. However, it is important in terms of radiation safety management to measure the radiation dose rate generated from the patient because the radiation emitted from the patient may cause the exposure. Research methods, it measured radiation dose-rate according to the elapsed time from 1 m from the upper abdomen of the patient by intake of radioactive iodine. Directly comparing the changes over time, high dose rate sensitivity and efficiency is statistically significant, and higher chamber than GM counter(p<0.05). Low dose rate sensitivity and efficiency in the chamber had lower levels than gm counter, but not statistically significant(p>0.05). In this study confirmed the characteristics of calibrated ionization chamber and GM counter according to the radiation intensity during high-dose radioactive iodine therapy by measuring the accurate and rapid radiation dose rate to the patient explains, discharged patients will be reduced to worry about radiation hazard of family and others person.

• Pediatric Infection and Vaccine
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• v.27 no.1
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• pp.1-10
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• 2020

A cluster of severe pneumonia of unknown etiology in Wuhan City, Hubei province in China emerged in December 2019. A novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was isolated from lower respiratory tract sample as the causative agent. The current outbreak of infections with SARS-CoV-2 is termed coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO). COVID-19 rapidly spread into at least 114 countries and killed more than 4,000 people by March 11, 2020. WHO officially declared COVID-19 a pandemic on March 11, 2020. There have been 2 novel coronavirus outbreaks in the past 2 decades. The outbreak of severe acute respiratory syndrome (SARS) in 2002-2003 caused by SARS-CoV had a case fatality rate of around 10% (8,098 confirmed cases and 774 deaths), while Middle East respiratory syndrome (MERS) caused by MERS-CoV killed 858 people out of a total 2,499 confirmed cases between 2012 and 2019. The purpose of this review is to summarize known-to-date information about SARS-CoV-2, transmission of SARS-CoV-2, and clinical features of COVID-19.