PET검사 작업환경에 있어서 APRON의 방어에 대한 고찰

이성욱,김승현,지봉근,이동욱,김정수,김경목,장영도,방찬석,백종훈,이인수,Lee, Seong-wook,Kim, Seung-hyun,Ji, Bong-geun,Lee, Dong-wook,Kim, Jeong-soo,Kim, Gyeong-mok,Jang, Young-do,Bang, Chan-seok,Baek, Jong-hoon,Lee, In-soo 대한핵의학기술학회 2014 핵의학 기술 Vol.18 No.1

PET/CT기기의 발달로 인한 검사시간의 단축과 대중화로 인해 검사건수도 꾸준히 증가하고 있다. 이는 방사선 작업종사자의 피폭선량도 함께 증가시키는 결과를 초래한다. 본 연구는 PET/CT 검사에 있어서 에너지가 강한 $^{18}F-FDG$를 apron을 착용 시 방사선 차폐율을 측정하고 차폐효과를 알아보고자 하였다. 또한 $^{99m}TC$과의 차폐율을 비교하여 방사선 작업종사자의 피폭선량을 최소화하는 것에 목적을 두고 진행하였다. 실험방법은 2013년 5월 2일부터 5월 10일까지 8일간 PET/CT 검사를 위해 본원을 방문한 10명의 환자를 대상으로 하였고 PET/CT 주요 작업공간인 $^{18}F-FDG$ 분배실, 환자 안정실($^{18F}$주사 후 환자 대기장소), PET/CT 검사실 모두 3곳을 선정하여 Apron장착 전과 apron장착 후로 나누어 선량율 변화를 측정하였다. 정확한 측정을 위해서 환자 또는 Source부터의 거리는 1 m로 고정하였다. 또한 Apron의 선량감소율을 비교하고자 $^{99m}TC$의 source에도 같은 방법을 적용하여 측정하였다. 측정결과 $^{18F}FDG$ 분배실에서 L-BLOCK만 있는 경우 평균 $0.32{\mu}Sv$였고 L-block+apron의 경우 $0.23{\mu}Sv$이였으며 두 경우의 선량과 선량율의 차이는 각각 $0.09{\mu}Sv$, 26%로 나타났다. 안정실에서 apron이 없는 경우 평균 $33.1{\mu}Sv$였고 apron이 있는 경우 평균 $22.3{\mu}Sv$였다. 두 경우의 선량과 선량율의 차이는 각각 $10.8{\mu}Sv$, 33%로 나타났다. PET/CT실에서의 apron이 없는 경우 평균 $6.9{\mu}Sv$였고 apron이 있는 경우 평균 $5.5{\mu}Sv$였다. 두 경우의 선량과 선량율의 차이는 각각 $1.4{\mu}Sv$, 25%로 나타났다. $^{99m}TC$은 apron이 없는 경우 평균 $23.7{\mu}Sv$였고 apron이 있는 경우 평균 $5.5{\mu}Sv$였다. 두 경우의 선량과 선량율의 차이는 각각 $18.2{\mu}Sv$, 77%나타났다. 실험결과 환자에게 투여한 후의 $^{99m}TC$의 경우 평균 77%의 차폐율을 나타내었고 $^{18}F-FDG$의 경우 평균 27%의 비교적 낮은 차폐율을 보였다. source 자체만을 비교하였을 때에 $^{18}F-FDG$는 17%의 차폐율을 보였고 $^{99m}TC$은 77%의 차폐율을 보였다. $^{99m}TC$에 비해 낮은 차폐효과이지만 $^{18}F-FDG$ 역시 apron에 대한 차폐효과가 있음을 알 수 있었다. 그러므로 PET/CT 검사에 있어서 $^{18}F-FDG$과 같은 고에너지에 맞는 apron을 착용한다면 방사선 작업종사자의 피폭선량을 최소화 할 수 있을 것으로 사료된다. Purpose: The advancement in PET/CT test devices has decreased the test time and popularized the test, and PET/CT tests have continuously increased. However, this increases the exposure dose of radiation workers, too. This study aims to measure the radiation shielding rate of $^{18}F-FDG$ with a strong energy and the shielding effect when worker wore an apron during the PET/CT test. Also, this study compared the shielding rate with $^{99m}TC$ to minimize the exposure dose of radiation workers. Materials and Methods: This study targeted 10 patients who visited in this hospital for the PET/CT test for 8 days from May 2nd to 10th 2013, and the $^{18}F-FDG$ distribution room, patient relaxing room (stand by room after $^{18}F-FDG$ injection) and PET/CT test room were chosen as measuring spots. Then, the changes in the dose rate were measured before and after the application of the APRON. For an accurate measurement, the distance from patients or sources was fixed at 1M. Also, the same method applied to $^{99m}TC's$ Source in order to compare the reduction in the dose by the Apron. Results: 1) When there was only L-block in the $^{18}F-FDG$ distribution room, the average dose rate was $0.32{\mu}Sv$, and in the case of L-blockK+ apron, it was $0.23{\mu}Sv$. The differences in the dose and dose rate between the two cases were respectively, $0.09{\mu}Sv$ and 26%. 2) When there was no apron in the relaxing room, the average dose rate was $33.1{\mu}Sv$, and when there was an apron, it was $22.3{\mu}Sv$. The differences in the dose and dose rate between them were respectively, $10.8{\mu}Sv$ and 33%. 3) When there was no APRON in the PET/CT room, the average dose rate was $6.9{\mu}Sv$, and there was an APRON, it was $5.5{\mu}Sv$. The differences in the dose and dose rate between them were respectively, $1.4{\mu}Sv$ and 25%. 4) When there was no apron, the average dose rate of $^{99m}TC$ was $23.7{\mu}Sv$, and when there was an apron, it was $5.5{\mu}Sv$. The differences in the dose and dose rate between them were respectively, $18.2{\mu}Sv$ and 77%. Conclusion: According to the result of the experiment, $^{99m}TC$ injected into patients showed an average shielding rate of 77%, and $^{18F}FDG$ showed a relatively low shielding rate of 27%. When comparing the sources only, $^{18F}FDG$ showed a shielding rate of 17%, and $^{99m}TC$'s was 77%. Though it had a lower shielding effect than $^{99m}TC$, $^{18}F-FDG$ also had a shielding effect on the apron. Therefore, it is considered that wearing an apron appropriate for high energy like $^{18}F-FDG$ would minimize the exposure dose of radiation workers.

N-doped $TiO_2$/PAN 복합 나노섬유의 제조와 광촉매 특성

이성욱,이태상,리강,원방방,황택성,이승구,Lee, Sung-Wook,Lee, Tae-Sang,Li, Gang,Won, Bang-Bang,Hwang, Taek-Sung,Lee, Seung-Goo 한국섬유공학회 2009 한국섬유공학회지 Vol.46 No.6

The $TiO_2$/PAN based composite nanofibers having photocatalytic activity were prepared by sol-gel process, electrospinning and post-treatments. Electrospinning solution was prepared by mixture of $Ti(OBu)_4$, PAN, acetic acid and DMF with different ratio. As-spun nanofibers were treated with different way to prepare the anatase $TiO_2$/PAN nanofibers and the N-doped $TiO_2$/PAN nanofibers. In this study, the morphology and diameter of the electrospun and heat treated composite nanofiber were analyzed, and crystal structure of nanofiber after heat treatment and N-doping was analyzed. Furthermore, photocatalytic decomposition of the nanofiber, crystallized in various condition, against the malachite green aqueous solution, was evaluated.

선미형상을 고려한 천수역에서의 조종성능에 관한 연구

이성욱,Lee, Sungwook 해양환경안전학회 2015 해양환경안전학회지 Vol.21 No.5

A numerical simulation studies were performed to investigate a manoeuvring characteristics as function of stern hull form with the mathematical model. In order to consider the effect of the stern hull form and obtain the manoeuvring characteristics, a parameter($C_{wa}$) which is aft. water plane area coefficient is modified. Because modifying $C_{wa}$(${\pm}2%$) means that the stern hull form is modified to V-type or U-type, the numerical simulation was performed with this modified $C_{wa}$. A changing trend for the manoeuvring characteristics not only in deep water but also in shallow water such as directional stability, turning and zig-zag was investigated and presented as the results. Present study showed that the manoeuvrability in shallow water largely changed when the draught and water depth ratio(=d/H) become 0.5, and the stern hull form can affect to the manoeuvrability of a vessel navigating in restricted water depth. In addition, it showed that approaching the stern hull to U-type makes the advance and tactical diameter of turning motion large and the overshoot angle of zig-zag motions small. Otherwise, it showed approaching the stern hull form to V-type makes the advance and tactical diameter of turning motion small and the overshoot angle of zig-zag motions large in the present study. 본 연구에서는 선미형상을 고려한 조종성능을 심수역 뿐만 아니라 천수역에 대해서 수치 시뮬레이션을 통해 검토하였다. 선미형상을 나타내는 파라메터 중 $C_{wa}$를 미소(${\pm}2%$)하게 변화시킴으로써 각 수역에서의 침로안정성, 선회 및 지그재그 성능이 어떤 변화를 보이고 그 경향이 어떻게 변화하는 지를 검토하였다. 선박의 조종성능 관점에서 흘수 대 수심의 비(=d/H)가 0.5 부근에서의 조종성에 큰 변화를 가져오는 중요 지점임을 알 수 있었고, 비대선(VLCC, 탱커 등)과 세장선(컨테이너)의 경우 선미형상의 변화에 따라 조종성능의 변화 정도가 많은 차이를 가질 수 있음을 알 수 있었다. 또한, $C_{wa}$를 감소(U형에 근접)시키면 선회운동에 있어서 advance 및 tactical diameter가 증가하고, 지그재그 운동에서는 track reach는 증가하지만 각 overshoot angle들은 감소한다. 이와 반대로, $C_{wa}$를 증가(V형에 근접)시키면 선회운동에 있어서 advance 및 tactical diameter는 감소, 지그재그 운동에서는 track reach는 감소, 각 overshoot angle 들은 증가함을 알 수 있었다.

문법관계 정보를 이용한 단계적 한국어 구문 분석

이성욱,Lee, Song-Wook 한국정보처리학회 2008 정보처리학회논문지B Vol.15 No.1

본 연구는 한국어 의존 구조를 결정하는 단계적 의존 구조 분석기를 제안한다. 각 단계에서는 주어진 문법관계의 후보열에서 올바른 문법관계를 결정하는데, 대상문법관계의 종류에 따라 독립적으로 수행된다. 문법관계의 후보열은 미리 학습된 지지벡터기계를 이용하여 주어, 목적어, 보어, 부사어 등 7가지의 문법관계로 추정한다. 각 단계에서는 지지벡터기계 분류기와 어절 간의 거리, 교차 구조 금지, 격 제한의 원칙 등의 한국어 언어 특성을 이용하여 대상문법관계를 결정하며, 모든 단계를 거쳐 최종적으로 전체 의존 구조와 문법관계가 결정된다. 트리 및 문법관계 부착 말뭉치를 이용하여 제안된 시스템을 구현 및 실험하였으며 약 85.7%의 정확률을 얻었다. This study aims to identify dependency structures in Korean sentences with the cascaded chunking. In the first stage of the cascade, we find chunks of NP and guess grammatical relations (GRs) using Support Vector Machine (SVM) classifiers for all possible modifier-head pairs of chunks in terms of GR categories as subject, object, complement, adverbial, etc. In the next stages, we filter out incorrect modifier-head relations in each cascade for its corresponding GR using the SVM classifiers and the characteristics of the Korean language such as distance between relations, no-crossing and case property. Through an experiment with a parsed and GR tagged corpus for training the proposed parser, we achieved an overall accuracy of 85.7%.

음향 임피던스를 해저면 입력인자로 이용하는 수중음장 계산

이성욱,오택환,나정열,이필호,윤종락,Lee Seongwook,Oh Taekhwan,Na Jungyul,Lee Phil-Ho,Yoon Jong Rak 한국음향학회 2006 韓國音響學會誌 Vol.25 No.1

천해에서의 수중음장 계산에서 음향 임피던스를 해저면 입력인자로서 도입하는 방안의 가능성을 고찰하였다. 먼저 탄성 해저면에서의 음파반사 특성을 고찰한 결과, 임계 접지각 이하에서 음향 임피던스는 접지각이 거의 $0^{\circ}$에 가까울 때의 임피던스 $Z_0$ 1개 값으로 근사가 가능함을 나타내었다. 이러한 특성과 'effective depth' 개념을 접목시켜 전달손실을 계산한 결과, 수중음장 계산에서 임피던스를 해저면 음향 특성을 나타내는 입력인자로 사용하는 것이 가능성이 있음을 확인하였다. The Possibility of using acoustic impedance as an input Parameter for computation of underwater acoustic field in shallow waters was investigated. Analysis of the acoustic reflection from the ocean bottom with shear wave effect showed that acoustic impedances below the critical grazing angle have nearly angle-independent property and could be approximated with a single value of near-grazing impedance $Z_0$. Computations of the Propagation loss based on the concept of 'effective depth' indicate that near-grazing bottom acoustic impedances could be used as an input parameter for simulation of the acoustic fields in shallow waters.

RF 마그네트론 스퍼터링 법에 의한 ATO 투명전도막의 특성

이성욱,박용섭,홍병유,Lee, Sung-Uk,Park, Yong-Seob,Hong, Byung-You 한국결정성장학회 2008 韓國結晶成長學會誌 Vol.18 No.2

본 연구에서는 ATO 박막의 전도 특성향상을 위하여 RF 마그네트론 스퍼터링을 이용하여, 6 wt%의 Sb가 첨가된 $SnO_2$ 박막을 합성을 진행하였으며, 박막합성시 스퍼터링 가스인 아르곤(Ar)과 반응가스인 산소($O_2$)의 분압 비율의 증가에 따른 ATO 박막의 구조적, 전기적, 광학적 특성들의 고찰하였다. 결과적으로 산소/아르곤의 비율이 0.11에서 $8{\times}10^{-3}[{\Omega}{\cdot}cm]$의 비저항과 85.17%, 그리고 retile 구조의 이상적인 전도특성과 투과특성, 그리고 결정화를 이룬 ATO 박막 얻었다. In this study, we synthesized ATO films using RF magnetron sputtering method consisted of $SnO_2$ target added Sb of 6 wt% and investigated the effect of $O_2$ on structural, electrical, and optical properties of ATO films. As a result, in case of $O_2$/Ar ratio of 0.11, we obtained ATO films exhibit the properties such as the resistivity about $8{\times}10^{-3}[{\Omega}-cm]$, the transmittance of 85.17%, and retile structure.

가오리형 수중글라이더의 형상설계 및 운동성능 해석

이성욱,정재훈,정상기,최형식,김준영,Lee, Sung-Wook,Jeong, Jae-Hun,Jeong, Sang-Ki,Choi, Hyeung-Sik,Kim, Joon-Young 대한임베디드공학회 2017 대한임베디드공학회논문지 Vol.12 No.5

Underwater glider with a single buoyancy engine could generally obtain propulsive forces by moving the center of buoyancy and gravity. Futhermore, The hull and internal structure of underwater glider are designed according to the purpose of long-time operation, high speed and a wide variety of payloads (sensors, communications and etc.). In this paper, Ray-type underwater glider featuring flatfish is considered in view of hydrodynamics. The hull design is especially performed by the analysis of fluid resistance and dynamic performance. The resistance performance is analyzed using the Computational Fluid Dynamics (CFD). In addition, a simulation program is implemented in order to verify the validity of dynamics modeling and dynamic performances.

In vitro Selection of Specific RNA Aptamers for the NFAT DNA Binding Domain

이성욱,Jung-Sun Cho,Young Ju Lee,Kyung-Sook Shin,정수진,Jungchan Park 한국분자세포생물학회 2004 Molecules and cells Vol.18 No.1

Nuclear factor of activated T cells (NFAT) plays a central role in the immune response, and the immunosuppressive drugs, cyclosporin A and FK-506, have been developed to inhibit it. However, due to the toxic effects of these drugs, which derive from their ability to inhibit calcineurin in non-immune tissues, the identification of small compounds that target NFAT directly could be an approach to developing less toxic immunosuppressive therapy. Using an in vitro selection technology termed SELEX on a combinatorial RNA library with 40 nucleotide-long random sequences, we have isolated two RNA aptamers to the NFAT DNA binding domain (DBD). Gel retardation assays and surface plasmon resonance measurements showed that the aptamers have a specific and high affinity (apparent KD~10 to 100 nM) for the NFAT DBD. Enzymatic probing analysis showed that the two RNA aptamers have similar structures and share a sequence that forms an apical loop. Moreover, RNase footprinting analysis showed that the shared sequence (GATATGAAGGA/ TGTG/AGAGAG) is critical for binding to both NFATp DBD and NFATc DBD. These results suggest that short RNAs identified in this study is a specific aptamer to NFAT DBD, and hence could be applied not only for the delineation of NFAT functions but for the development of potent immune modulating lead compounds.

Combustion and emission characteristics of HCNG in a constant volume chamber

이성욱,Han-Seung Lee,박영준,조용석 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2

Finding an alternative fuel and reducing environmental pollution are the main goals for future internal combustion engines. Hydrogenmethane (HCNG) is now considered an alternative fuel due to its low emission and high burning rate. An experimental study was carried out to obtain fundamental data for the combustion and emission characteristics of pre-mixed hydrogen and methane in a constant volume chamber (CVC) with various fractions of hydrogen-methane blends. A pre-mixed chamber was used to obtain a good mixture of these gases. Exhaust emissions were measured using a Horiba exhaust gas analyzer for various fractions of hydrogen-methane blends. The results showed that the rapid combustion duration was shortened, and the rate of heat release elevated as the hydrogen fraction in the fuel blend was increased. Moreover, the maximum mean gas temperature and the maximum rate of pressure rise also increased. These phenomena were attributed to the burning velocity, which increased exponentially with the increased hydrogen fraction in the fuel blend. Exhaust HC and CO₂concentrations decreased, while NO_x emission increased with an increase in the hydrogen fraction in the fuel blend. Our results could facilitate the application of hydrogen and methane as a fuel in the current fossil hydrocarbon-based economy and the strict emission regulations in internal combustion engines.

강직을 동반한 전신 발작을 호소하는 심인성 비간질성 발작 환자에 대한 복합 한의치험 1례

이성욱,이현규,배인후,조기호,문상관,정우상,권승원,진철,Lee, Seong Wook,Lee, Hyun-Ku,Bae, In Hu,Cho, Ki-Ho,Moon, Sang-Kwan,Jung, Woo-Sang,Kwon, Seungwon,Jin, Chul 대한중풍순환신경학회 2021 대한중풍.순환신경학회지 Vol.22 No.1

Psychogenic Non Epileptic Seizure (PNES) refers to a case in which symptoms are similar to epileptic seizures (ES), but ES do not appear in EEG and temporary abnormalities caused by physical diseases are also excluded. Psychotherapy and pharmacotherapy are most commonly used, but standard treatment for PNES has not been established and there is no alternative treatment available in the case of patients those treatments are not applied. We herein report a case of 46 year old male diagnosed with PNES who suffered from generalized tonic-clonic seizures. The patient underwent korean medical treatment by acupuncture and herbal medicine. The clinical symptom was evaluated by assessing occurrence frequency, number of seizures per 28 days. Compared to the period without korean medical treatment, the number of seizures decreased during the treatment period. The present case report suggested that korean medical treatment could be an effective option for those PNES patients complaining generalized tonic-clonic seizures.