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RISS 인기검색어
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- 저자 : 권성옥(Kwon, Sung Ok) (검색결과 45 건)
- 무료
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권성옥(Seong Ohk Kwon),하동윤(Dong Yoon Ha),이희정(Hee Jeong Lee),김선기(Seon Ki Kim),서동수(Dong Soo Suh),장동수(Dong Soo Chang) 대한CT영상기술학회 2005 대한CT영상기술학회지 Vol.7 No.1
Purpose In this study, In order to decrease of exposure rate and attain better image quality for protect pediatric patients. We investigated to find the optimal exposure factors for pediatric patients in computed tomography. Materials and methods : We performed this study to assesment exposure rates from using the pencil type Ionization chamber. We are using the 16 channel multi detector computed tomography(16-MDCT) on General Electric Lightspeed ultra 16. In this Experimental phantom made of each brain and abdomen types to 5kg, 5~10kg, 10~20kg, 20~40kg, 40~60kg, more 60kg etc(Standard of korea child growth 표). Results The results obtained were as followed : 1) Optimal Exposure factor of brain Phantom is : 100kVp~120kVp, 160mA~200mA(Weighting steps) 2) Optimal Exposure factor for Abdomen Phantom is : 80kVp~100kVp, 60mA~180mA(Weighting steps) 3) Measured Exposure rates : 10%~180%,(using the adult Exposure factor) 4) Measured Exposure rates : -30%~110%,(decease of one steps Exposure factor) 5) Abdomen Phantom Exposure rates is more than brain Phantom caused of beam hardening artifact in brain. Conclusion From the results of these studies, It is suggested that which are using the optimal exposure factor to decrease exposure rate and attain better image quality for protect pediatric patients. We are need to standard official certification in order to avoid of radiation hazard.
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Dual Source CT와 Multi Detector CT에서 Coronary 검사의 방사선량 분석
권성옥(Seong Ohk Kwon),하동윤(Dong Yoon Ha),최준호(Joon Ho Choi),이상우(Sang Woo Lee),서동수(Dong Soo Suh) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1
Purpose This study compared an exposure dose of DSCT with MDCT in cardiac CT and we analyzed how much the radiation dose increased or decreased. Materials and Methods For an experiment, CT device for the human body was used by 16 channel MDCT(Multi Detecter CT) manufactured by siemens and DSCT(Dual Source CT) called by SIEMENS Somatom Definition CT. It is available for supplying two source with each different kVp and mAs, processing and gathering the data at the same time. we used ECG Simulator(Marquette Electronics. USA) for examining a change of Heart Rate. An experiment method compares CTDIvol and CTDIDLP of DSCT with MDCT and is to measure. it was performed by using ECG Simulator in DSCT Coronary study, giving Heart Rate with a variety of numerical value, such as 50bpm, 55bpm, 60bpm, 65bpm, 70bpm, 75bpm, 80bpm, 85bpm, 90bpm, 95bpm, 100bpm, 105bpm, 110bpm, according to high or low of each heart rate, comparing and measuring CTDIvol and CTDIDLP, we can know whether there is some differences. Results 1. The Coronary study protocol of MDCT is 120kVp, 600mAs, Rotation time 0.37sec, Scan Time 18~20sec. CTDIvol and CTDIDLP measured each 46.80mGy, 936mGy. The Coronary study protocol of DSCT is 120kVp, 300mAs, Rotation time 0.33sec, Scan Time 8~10sec. CTDIvol and CTDIDLP measured each 47.45mGy, 427.05mGy. As a result, CTDIDLP was reduced about 55% in DSCT compared with Multi Detecter CT though CTDIvol is similar. 2. Heat rate of Coronary Study used ECG Simulator in DSCT is 50bpm, 55bpm, 60bpm, 65bpm, 70bpm, 75bpm, 80bpm, 85bpm, 90bpm, 95bpm, 100bpm, 105bpm, 110bpm. according to high or low of each heart rate, CTDIvol is measured to 60.81mGy in 50bpm and 29.llmGy in 110bpm. 3. CTDIvol and CTDIDLP of MDCT used Coronary study protocol is measured to 46.80mGy and 936mGy. measured CTDIvol of DSCT is 29.11~60.81mGy in 50bpm ~110bpm heart rate and CTDIDLP is measured to 261.99~547.29mGy. Conclusion The Dual Source CT is increased 29.9%~0.1% of CTDIvol in 50bpm ~ 110bpm compared with the Multi Detecter CT. And the CTDIvol in 70bpm ~ 110bpm was reduced by 9%~37.8. In the Single Source the Table speed came to be late as a heart rate increase. On the other hand, The Table speed of DSCT did fast according to the increase of the Heart Rate and The Scan time is reduced. When heart rate is slow, CTDIDLP of Dual Source CT is reduced by 41.6 % compared with Multi Detecter CT and When heart rate is fast, CTDim.P of Dual Source CT is reduced by 72.1% compared with Multi Detecter CT.
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CT검사로 인한 방사선 피폭이 혈액에 미치는 생물학적 변화에 관한 연구
권성옥(Seong Ohk Kwon),김선기(Seun Ki Kim),김강환(Kang Hwan Kim),하동윤(Dong Yoon Ha) 대한CT영상기술학회 2009 대한CT영상기술학회지 Vol.11 No.1
Purpose For this study we collected patients blood with performing CT exam before and after at our hospital and to research about radiation dose influence of blood cell count. Materials and methods The research object was implemented dynamic liver scan patient and blood analysis was performed with blood collected at CT exam before and after. In total 46 people(35 M, 11 Fe, mean age 57; range 30~77 years), weight ranged from 45kg to 112kg; mean 64kg, radiation dose ranged from 685mGy to 2,548mGy; mean 1,615mGy. The scan were performed with GE LightSpeed Ultra 16 Plus, Siemens Somatom Sensation 16, and blood analysis equipment using coulter counter theory, and sampling were used as EDTA tube. Blood examination value was compared with WBC, RBC, Hb, platelet, neutrophil, lymphocyte etc. Results WBC was decreased up to 46% compared to other cell. RBC cell was increased in 5 people and decreased in 41 people. Hb was increased up to 23% in 39 people and decreased in 7 people. Platelet was increased up to 13% in 35 people and decreased in 40 people. Neutrophil was increased up to 18.9% in 35 people and decreased in 40 people. Finally, lymphocyte was increased up to 6.6% but decreased 10.8% in 34 people. Conclusion Althougt we did not know the decrement or increase of the blood corpuscles whether radiation dose or not patient condition, but blood corpuscles count has varied in human body after CT examination. Further validation study is needed to know effect of radiation exposure to human body, because blood corpuscles is destroyed and newly born successively, and to understand about the precise process after radiation energy absorption.
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SPECT filter의 cut off level에 따른 반폭치(FWHM) 크기에 관한 연구
박성옥,권수일,Park, Soung-Ock,Kwon, Soo-Il 대한방사선기술학회 2003 방사선기술과학 Vol.26 No.2
Filtering is necessary to reduce statistical noise and to increase image quality in SPECT images. Noises controled by low-pass filter designed to suppress high spatial frequency in SPECT image. Most SPECT filter function control the degree of high frequency supression by chosing a cut of frequency. The location of cut off frequency determines the affect image noise and spatial resolution. If select the low cut off frequency, its provide good noise suppression but insufficient image quantity and high cut off frequencies increase the image resolution but insufficient noise suppression. The purpose of this study was to determines the optimam cut off level with comparison of FWHM according to cut off level in each kiters-Band-limited, Sheep-logan, Sheep-logan Hanning, Generalized Hamming, Low pass cosine, Parazen and Butterworth filter in SPECT camera. We recorded image along the X, Y, Z-axis with $^{99m}TcO_4$ point source and measured FWHM by use profile curve. We find averaged length is $9.16\;mm{\sim}18.14\;mm$ of FWHM in X, Y, and Z-axis, and Band-limited and Generalized Hamming filters measures 9.16 mm at 0.7 cycle/pixel cut off frequency. 영상재구성에 있어 잡음(noise)을 제거하고 공간 분해능과 대조도 분해능을 향상시킬 수 있는 filter에서 cut off 주파수 level에 따라 영상의 질에 영향을 미치는 경향을 반폭치(FWHM : full width at half maximum)측정방법을 이용하여 비교하였다. 선택한 filter의 종류는 Band-limited, Sheep-logan, Sheep-logan Hanning, Generalized Hamming, Low pass cosine, Parazen, 그리고 Butterworth filter이다. SPECT 영상을 기록하기 위한 점선원(point source)으로 방사성의약품 $^{99m}TcO_4$을 이용하였으며 점선원에 대하여 각각의 filter에서 cut off 주파수 준위별로 영상을 기록하고 axial transverse, coronal sagittal... fh의 section image의 profile 곡선에서 반폭치을 측정하여 비교하였다. 본 연구에서 사용한 filter들에 있어서는 cut off level에 따라 X, Y, 그리고 Z축 방향으로의 평균 FWHM의 길이가 $9.16\;mm{\sim}18.14\;mm$까지 측정되었는데 cut off level 0.7에서 Generalized Hamming filter와 Band limited filter의 경우 9.16 mm로 반폭치의 길이가 제일 짧은 것으로 나타났다.
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인체 간암세포에서 β-lapachone 처리에 의한 Tight Junction 관련 유전자의 변화
김성옥,권재임,김기영,김남득,최영현,Kim, Sung-Ok,Kwon, Jae-Im,Kim, Gi-Young,Kim, Nam-Deuk,Choi, Yung-Hyun 한국생명과학회 2007 생명과학회지 Vol.17 No.9
${\beta}-lapachone$은 남미지역에서 자생하는 Tabebuia avellanedae라는 나무의 수피에서 동정된 quinone계 물질로서 다양한 인체암세포에서 항암효과가 있는 것으로 알려져있다. 본 연구에서는 ${\beta}-lapachone$의 암 전이 억제에 대한 연구의 일환으로 HepG2 및 Hep3B 인체 간암 세포의 전이관련 유전자의 발현에 미치는 ${\beta}-lapachone$의 영향을 조사하였다. MTT assay 및 세포형태변화 관찰 결과에서 ${\beta}-lapachone$ 처리에 따라 HepG2와 Hep3B 세포들은 ${\beta}-lapachone$ 농도 의존적으로 세포의 증식이 억제되었으며 그 형태적 변형도 동반하였다. ${\beta}-lapachone$처리에 의한 암 전이 지표가 되는 IGF-lR, Tjs (ZO-1, claudin-3,-4) 및 Tj 조절인자(${\beta}-catenin$)의 발현을 RT-PCR과 Western blot analysis를 통하여 확인한 결과 ${\beta}-lapachone$ 처리가 IGF-1R의 발현 억제와 Tj 유전자 발현의 증가를 유도함으로써 ${\beta}-lapachone$이 Tj를 강화하여 암세포의 전이 억제작용을 하는 것으로 관찰 되었다. 이상의 결과는 인체 간암세포에서 ${\beta}-lapachone$의 항전이 작용의 이해에 중요한 기초 자료가 될 것으로 생각한다. A hallmark of cancers is 'leaky' tight junctions (Tjs). TJs mediated paracellular permeability is elevated and TJs maintained cell polarity is frequently lost. Concomitantly, TJs-associated proteins including members of the claudin family of proteins are dysregulated. Recent findings indicate that these TJs changes can contribute to cancer progression. In this study, we examined the effects of ${\beta}-lapachone$, a quinone compound obtained from the bark of the lapacho tree (Tabebuia avellanedae), on the Tjs-associated regulators in human hepatocarcinoma cell lines, HepG2 and Hep3B. ${\beta}-lapachone$ treatment downregulated the levels of insulin-like growth factor 1 receptor (IGF-lR) proteins in both HepG2 and Hep3B cells. But the levels of claudin-3 and -4 proteins were increased in ${\beta}-lapachone$-treated HepG2 and Hep3B cells. And also the zonnula occludens-l (la-I) and p-catenin protein levels by ${\beta}-lapachone$ were increased in a time-dependent manner. However, claudin-3 and -4 mRNA levels were uninhibited by ${\beta}-lapachone$ in HepG2 and Hep3B. The present results suggest that the upregulation of claudin-3 and -4 protein levels by ${\beta}-lapachone$ occurs by a post-transcriptional mechanism and points to a novel mechanism by ${\beta}-lapachone$.
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플라즈마 표면처리에 의한 Silk/PLA 바이오복합재료의 계면접착
추보영,권미연,이승구,조동환,박원호,한성옥,Chu, Bo Young,Kwon, Mi Yeon,Lee, Seung Goo,Cho, Donghwan,Park, Won Ho,Han, Seong Ok 한국접착및계면학회 2004 접착 및 계면 Vol.5 No.4
견섬유와 폴리라틱산(PLA) 사이의 계면접착 특성을 향상시키기 위하여 천연섬유 표면을 아르곤과 에틸렌 플라즈마로 각각 처리하였다. 플라즈마 표면처리 후, 견섬유의 표면 모폴로지와 접착이 크게 변화하였다. 다음의 여러 플라즈마 처리조건이 본 연구에 사용되었다: 10, 25, 50 그리고 150 W의 전력, 1, 3, 5, 7 그리고 10분의 처리시간 및 10과 50 sccm의 가스흐름속도, 플라즈마 처리된 Silk/PLA 바이오복합재료의 계면전단강도는 단섬유 micro-droplet debonding 시험방법으로 측정하였다. 결과는 Silk/PLA 바이오복합재료의 계면접착을 향상시키기 위한 최적의 플라즈마 처리 조건을 제공하여 주었다. Silk fibers were subjected to argon and ethylene plasma treatments in order to improve the interfacial adhesion with polylactic acid (PLA). After the plasma surface treatment, the surface morphology and surface adhesion of silk fibers to the PLA resin were largely changed. Various plasma treatment conditions were used in this work: 10, 25, 50, 100 and 150 W of electric power, 1, 3, 5, 7 and 10 minutes of treatment time, and 10 and 50 sccm of a gas flow rate. The interfacial shear strength of plasma-treated Silk/PLA biocomposites was measured by a single fiber micro-droplet debonding test method. The result provided an optimal plasma treatment condition to obtain the improved interfacial adhesion in the Silk/PLA biocomposites.
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