Adaptive Statistical Iterative Reconstruction 기법을 이용한 Bone SPECT/CT 검사에서 피폭량 감소 방안

최진욱,최현준,박찬록,조성욱,김진의,이재성,이동수,Choi, Jin-Wook,Choi, Hyeon-Jun,Park, Chan-Rok,Cho, Sung-Wook,Kim, Jin-Eui,Lee, Jae-Sung,Lee, Dong-Soo 대한핵의학기술학회 2014 핵의학 기술 Vol.18 No.1

ASIR기법은 statistical noise modeling을 사용하여 CT image를 reconstruction하는 방법으로, mA를 낮춰도 이미지 질을 보전하며 noise reduction 효과가 있다고 알려져 왔다. 본 논문은 본원에서 주로 하는 bone SPECT/CT에 ASIR 기법을 적용하여 이미지를 평가하였다. GE의 Discorvery 670을 이용하여 120 kVp, 100 mA를 기준으로 mA를 변화시켜서 ASIR의 적용 전과 적용 후 영상을 비교하였다(ASIR level: 20-80%). Anthropomorphic phantom으로 ASIR (%)의 변화에 따른 SPECT image의 감쇠 보정 정도를 측정하였다. 두번째로 ACR phantom으로 CT image의 CNR, image noise, spatial resolution을 평가하였다. 세 번째로 lower torso phantom을 이용하여 spine에 최적화할 수 있는 ASIR level을 선택한 후 2명의 bone SPECT/CT follow up 환자에게 ASIR를 적용하여 영상을 획득한 후 5년 이상의 경험이 있는 10명의 방사선사에게 blind test를 시행하였다. SPECT의 영상의 감쇠 보정 정도는 ASIR의 변화와는 무관하게 모두 유의한 차이가 없었다(P>0.05). ASIR을 적용했을 때 CT image의 noise는 mA의 변화에 따라 최소 17%에서 최대 52%까지 감소하였다. ASIR를 적용하지 않았을 때 CNR은 40 mA에서 0.42를 보여준 반면 ASIR를 적용한 40 mA (ASIR 60%)에서도 0.8 이상을 유지하였다. High contrast 영역의 비교에서는 ASIR 적용과 상관없이 40 mA까지 12 lp/cm 영역을 구별할 수 있었다. Lower torso phantom의 spine image에서 100 mA image와 육안적으로 비슷한 ASIR level은 60% (40 mA) 정도였고, bone SPECT/CT에 적용한 후 blind test에서 육안적으로 ASIR를 적용하지 않았을 때와 차이를 구별하지 못하였다. 본 논문의 결과는 SPECT/CT에서 ASIR 기법을 사용했을 때 SPECT와 CT image의 특별한 영상의 질 저하 없이 radiation dose를 줄일 수 있다는 것을 보여준다. 또한 관심부위가 bone에 한정되어 있는 bone SPECT/CT 특성상 더 높은 ASIR level도 가능할 것으로 사료된다. Purpose: Adaptive statistical iterative reconstruction (ASIR) technique is a reconstruction method of CT image using statistical noise modeling which is known to reduce image noise and to preserve image quality despite reducing radiation dose. The aim of this study is to evaluate images using ASIR on bone SPECT/CT which is primarily performed in our hospital. Materials and Methods: We compared the images of applied ASIR (ASIR level: 20-80%) and none ASIR by changing the mA based on 120 kVp, 100 mA using Discovery NM/CT 670 (GE, U.S.A). First, we evaluated attenuation correction in SPECT image by changing the ASIR level using Anthropomorphic phantom. Second, we compared the contrast to noise ratio (CNR), image noise and spatial resolution in CT image using ACR phantom. Third, after selecting the ASIR level applicable patient using lower torso phantom, we examined 2 patients who followed up bone SPECT/CT and we performed blind test. Results: The degree of attenuation correction in SPECT image showed no significant difference between applied ASIR and none ASIR (P>0.05). When applied ASIR, the noise of CT image were reduced at least 17 up to 52% by changing the mA. The CNR of image with ASIR was maintained more than 0.8 at 40 mA (ASIR 60%) while those without ASIR showed 0.42 at standard 40 mA. In comparison of the high contrast object, we distinguished 12 line pairs/cm at 40 mA regardless of appling ASIR. Comparison of the patients image applied ASIR level 60% (40 mA) which found out by spine image of lower torso phantom showed no signigicant difference between applied ASIR and none ASIR in blind test. The CTDIvol and DLP for applied ASIR 60% showed decreased by 60%, 60% on average than using standard mA. Conclusion: The study show that the radiation dose in SPECT/CT using ASIR can be reduced despite degradation of SPECT and CT images. In addition, higher ASIR level could be possibly applied characteristics of SPECT/CT that region of interest is limited to bone.

1-Day Protocol을 사용하는 Brain Perfusion SPECT에서 LEUR 콜리메이터의 유용성

최진욱,김수미,이형진,김진의,김현주,이재성,이동수,Choi, Jin-Wook,Kim, Soo-Mee,Lee, Hyung-Jin,Kim, Jin-Eui,Kim, Hyun-Joo,Lee, Jae-Sung,Lee, Dong-Soo 대한핵의학기술학회 2011 핵의학 기술 Vol.15 No.1

1-day protocol method는 DIAMOX 영상에서 basal 영상을 감산시키는 방법으로 혈관 예비능을 평가하는데 있어서 매우 유용한 검사지만, 검사시간이 길기 때문에 움직임에 의한 불가피한 재검사율이 높다. 기하학적으로 차이가 있는 fan-beam 콜리메이터와 parallel 콜리메이터 중 임상적으로 1-day protocol method에 가장 효율적인 콜리메이터가 무엇인지 알아보았다. 삼중 헤드 감마카메라인 triad XLT 9 (TRIONIX)와 세 가지 콜리메이터(low energy high resolution-parallel beam: LEHR-par, ultra resolution-fan beam: LEUR-fan, super fine-fan beam: LESR-fan)를 사용하였다. PET/SPECT performance phantom, Hoffman 3D phantom, volunteer 실험을 실시하여 세 가지 콜리메이터의 감도, 대조도, 해상력, 영상의 질을 비교 측정하였다. Pixel size를 fan-beam 콜리메이터와 동일하게 하기 위하여 parallel 콜리메이터 실험 시 zoom factor를 2.0으로 변경하였다. Scan time은 50 kcounts/frame을 만족하게 하였으며 filtered back projection (FBP)의 재구성 방법을 사용하였고 각 콜리메이터 별 최적의 영상을 위하여 cut off 값을 변화하면서 비교 측정하였다. 총 획득 계수가 동일한 조건에서 해상력과 percent background variability는 LESR과 LEUR이 LEHR보다 우수한 결과를 나타내었고, 영상의 육안평가에서 선호도는 LESR, LEUR, LEHR 순이었다. 영상 획득 시간은 LESR이 낮은 감도로 인하여 LEUR과 LEHR보다 약 2배 더 길게 소요됐다. Volunteer 실험의 결과 LESR을 사용할 때보다 LEUR 또는 LEHR을 사용 할 때 약 10-14분 정도 시간이 감소했다. 1-day protocol method는 단 한 번의 움직임에도 재검사가 불가피하기 때문에 적절한 분해능뿐만 아니라 높은 감도의 유지를 위해 적절한 검사 방법의 확립이 중요하다 할 수 있다. 본 연구에서 동일한 계수를 획득할 경우 LEUR은 LESR보다 2배의 시간을 감소시킬 수 있었고 영상의 육안평가나 해상력도 LESR과 임상적으로 큰 차이를 보이지 않았으므로 Brain SPECT의 1-day protocol method에 가장 적합할 것으로 사료된다. Purpose: Basal/Acetazolamide-challenged brain perfusion SPECT is very useful to assess cerebral perfusion and vascular reserve. However, as there is a trade off between sensitivity and spatial resolution in the selection of collimator, the selection of optimal collimator is crucial. In this study, we examined three collimators to select optimal one for 1-day brain perfusion SPECT. Materials and Methods: Three collimators, low energy high resolution-parallel beam (LEHR-par), ultra resolution-fan beam (LEUR-fan) and super fine-fan beam (LESFR-fan), were tested for 1-day imaging using Triad XLT 9 (TRIONIX). The SPECT images of Hoffman 3D brain phantom filled with 99mTc of 170 MBq and a normal volunteer were acquired with a protocol of 50 kcts/frame and detector rotation of 3 degree. Filterd backprojection (FBP) reconstruction with Butterworth filter (cut off frequencies, 0.3 to 0.5) was performed. The quantitative and qualitative assessments for three collimators were performed. Results: The blind tests showed that LESFR-fan provided the best image quality for Hoffman brain phantom and the volunteer. However, images for all the collimator were evaluated as 'acceptable'. On the other hand, in order to meet the equivalent signal-to-noise ratio (SNR), total acquisition time or radioactivity dose for LESFR-fan must have been increased up to almost twice of that for LEUR-fan and LEHR-par. The volunteer test indicated that total acquisition time could be reduced approximately by 10 to 14 min in clinical practice using LEUR-fan and LEHR-par without significant loss on image quality, in comparison with LESFR-fan. Conclusion: Although LESFR-fan provides the best image quality, it requires significantly more acquisition time than LEUR-fan and LEHR-par to provide reasonable SNR. Since there is no significant clinical difference between three collimators, LEUR-fan and LEHR-par can be recommended as optimal collimators for 1-day brain perfusion imaging with respect to image quality and SNR.

154 kV급 HTS 케이블의 절연설계 및 굴곡시험

최진욱,최재형,임응춘,김해종,조전욱,김상현,Choi, Jin-Wook,Choi, Jae-Hyeong,Lim, Eung-Choon,Kim, Hae-Jong,Cho, Jeon-Wook,Kim, Sang-Hyun 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.11

It is important that study on cryogenic electrical insulation design to develop the cold dielectric(CD) type HTS cable because the cable is operated under the high voltage environment in cryogenic temperature. This paper proposes two types of insulation design to carry out the maximum insulation design for 154 kV-class HT cable. The proposed insulation design method takes into consideration AC and lightning impulse withstand voltage so as to prevent AC breakdown for power frequency operating voltage during operating the cable and breakdown for lightning impulse voltage. The final insulation thickness is determined by selecting high value out of two insulation thickness calculated through the two insulation design methods. And we researched electrical insulation characteristics of HTS cable according to bending ratio and the number of bending.

하악골의 불연속 결손부 재건 시 비혈행화 장골이식술의 골흡수율에 관한 연구

최진욱,이충오,황희돈,김진욱,권대근,김진수,이상한,Choi, Jin-Wook,Lee, Chung-O,Hwang, Hee-Don,Kim, Jin-Wook,Kwon, Tae-Geon,Kim, Chin-Soo,Lee, Sang-Han 대한악안면성형재건외과학회 2012 Maxillofacial Plastic Reconstructive Surgery Vol.34 No.6

Purpose: Mandible resection and discontinuity defect created lead to aesthetic and functional problems. The iliac crest bone graft exhibits relative ease for bone harvesting, possibility of two team approach, ability to close the wound primarily, large amount of corticocancellous bone and relatively few complications. Whereas the use of free vascularized flaps has donor site morbidity and worse-fitting bone contour, the use of nonvascularized iliac bone graft has advantages in the operation time and patients' recovery time. So, nonvascularized iliac bone graft could be an attractive option. Methods: Twenty-one patients (M:F=1:1.1) underwent iliac crest bone harvesting for reconstruction of mandibular discontinuity defect (mean length : $61.6{\pm}17.8$ mm), from May 2005 to October 2011 at the Department of Oral and Maxillofacial Surgery in Kyungpook National University. The average age was $44.1{\pm}16.4$ years and the mean follow up periods was $28.2{\pm}22.7$ months. Bone resorption rate, according to age, sex, primary lesion, location and distance of defect, type of fixation plate, time of graft and pre-operative radiation therapy, were measured in each patient. Results: The mean bone resorption rate was $16.1{\pm}9.0%$. Bone resorption rate was significantly increased in mandibular defect that is over 6 cm in size (P=0.015, P<0.05) and the cases treated pre-operative radiation therapy (P=0.017, P<0.05). All was successfully fixed and maintained for the long-term follow-up. There were a few donor site complications and almost all patients were shown favorable outcome without severe bone resorption in this study. Conclusion: The nonvascularized iliac bone graft seems to be a reasonably reliable treatment option for reconstruction of mandibular discontinuity defects.

고분자 표면의 혈관내피세포 부착력에 관한 연구

최진욱,유규하,민병구,Choi, Jin-Wook,Ryu, Gyu-Ha,Min, Byoung-Goo 대한의용생체공학회 1990 의공학회지 Vol.11 No.1

To improve antithrombogenicity of polymer that used in vascular graft and artificial organs, seeding of human endothelial cells on the polyurethane was studied. Human endothelial cells were ismlated from human umbilical veins, using type I collagenase, and identified with goat anti vWF antibodies. Human endothilial cell seeding was tried upon the polyurethane which has good mechanical property and resists stresses. The hydrophobic polyurethane surface was changed hydrophilic by corona discharf:e treatment. Surface hydrophilicity was measured with Wilhemly plate method and the goniometer. To evaluate matrix protein adsorption, fibronectin adsorption test was done. To eveluate cell adhesion, human endothelial cell attachment forces were measured rising a perfusion chamber of , ism diamter. Less cells were detached from the hydrophilically treated polyurethane. This showed that corona discharge on the polyurethane could improve matrix adsorption and endothelial cell attachment.

해외건설 수주경쟁력 향상을 위한 ODA (Official Development Assistance) 활용방안

최진욱,김재준,이한승,전낙근,Choi, Jin-Wook,Kim, Jae-Jun,Lee, Han-Seung,Jeon, Rak-Keun 한국건설관리학회 2007 건설관리 : 한국건설관리학회 학회지 Vol.8 No.5

The domestic construction market is recently daunted because of the sustainable real estate regulation policy by the government. In other aspect, after the WTO(World Trade Organization)system opened overseas construction is growing continuously with grow of international economy and opening of market through world. Therefor needs to establish strategy on expansion or over seas construction competitive power. The purpose of this research is expansion on over seas construction competitive power by suggesting project cost guarantee methods to Owner and cost guarantee methods are Official Development Assistance(ODA). Accordingly, this research analyzed a developed $country^{\circ}{\phi}s$ ODA and domestic ODA. Moreover, survey to Expert of related field about over seas construction and ODA for identified problems. Especially, based on the results it intends to analyzed domestic ODA competitive power and improve strategy to competitive power of receive an order on over seas construction. 정부의 지속적인 규제 정책으로 인해 국내 건설시장은 위축되어 있는 반면 해외 건설시장은 꾸준한 성장세를 보이고 있고, WTO(World Trade Organization)체제 출범 이후 국제적인 개방화가 가속되고 있다. 따라서 우리나라의 해외건설도 과거의 단순 입찰방식을 지양하고 해외건설 수주경쟁력 확대를 위한 전략 수립이 필요한 실정이다. 본 연구는 해외건설 분야에서 사업초기에서부터 발주처에게 프로젝트의 재원확보 방안을 제시함으로써 수주경쟁력을 증대시키는 것을 연구의 주제로 삼았으며 재원확보 방안으로 양허성(원조성격)을 지닌 공적개발원조(ODA)를 대상으로 하였다. 본 연구에서는 선진국 및 우리나라의 공적개발원조를 분석하고, 관련 분야 전문가를 대상으로 해외건설 및 공적개발원조에 대한 설문조사를 실시하여 현황 및 문제점을 알아보았으며, 이를 바탕으로 우리나라 공적개발원조의 경쟁력을 분석하고 해외건설 수주경쟁력 확대를 위한 전략을 제안하였다.

갑상선 종양에서 Heat Shock Protein70과 Heat Shock Protein90의 발현 양상

최진욱,김진영,박철영<SUP>1<.SUP>,오기원<SUP>1<.SUP>,임성희<SUP>1<.SUP>,박성우<SUP>1<.SUP>,조현득<SUP>2<.SUP>,이명준<SUP>3<.SUP>,김이수,Jin Wook Choi,M.D.,Jin Yong Kim,Cheol Young Park,M.D.<SUP>1<.SUP>,Ki Won Oh,M.D.<SUP>1<.SUP> 대한갑상선-내분비외과학회 2004 The Koreran journal of Endocrine Surgery Vol.4 No.2

Purpose: Heat shock proteins (hsps) are synthesized by cells in response to various stress conditions, including carcinogenesis. The expression of hsps in neoplasia has been implicated in the regulation of cell signaling pathway such as cell survival and apoptosis. This study aimed to determine whether hsps expression in various thyroid neoplasia are significant and to identify the possibility as a therapeutic molecular target. Methods: We examined the expression of the hsp70 and hsp90 on tissue section from 53 thyroid tissues (16 normal tissues; 11 nodular hyperplasia; 12 follicular adenomas; 14 papillary carcinomas) using immunohistochemistry. Hsps expression was scored according to the percentage of positively stained cells (grade 0 to grade III). Results: For hsp70, all of the 53 tissues showed over- expression. 100% (16/16) of normal thyroid tissue and 87.0% (20/23) of benign tissue were categorized as grade I or II. In comparison, the carcinoma tissues showed expression in 64.3% with grade III. For hsp90, almost of normal thyroid tissue and benign tumors showed no expression (87.5% in normal tissues, 91.3% in benign tumors). However, all of carcinoma tissues showed expression and 78.6% (11/14) of carcinoma were in grade II or III. Conclusion: In current study, the pattern of expression for hsp70 and hsp90 in normal, benign, malignant thyroid tissues suggests that heat shock proteins might have some role in tumorigenesis in thyroid. Since there have been no reports on heat shock proteins and thyroid, further study is necessary and could give us clinically significant clue for diagnosis and treatment. (Korean J Endocrine Surg 2004; 4:79-84)

SESSION 11 . 컴퓨터 활용 : 무인 자동차 개발 연구

최진욱,한민홍 ( Jin Wook Choi,Min Hong Han ) 대한산업공학회 1993 대한산업공학회 추계학술대회논문집 Vol.1993 No.-

공장 및 회장의 원발성 종양

최진욱(Jin Wook Choi),정춘식(Choon Sik Jeong),김창남(Chang Nam Kim),이호정(Ho Jung Lee),유창식(Chang Sik Yu),김진천(Jin Cheon Kim) 대한외과학회 1999 Annals of Surgical Treatment and Research(ASRT) Vol.56 No.2

Multilayer 식용코팅의 레몬 저장성에 대한 효과

최진욱 ( Jin Wook Choi ),이승주 ( Seung Ju Lee ) 한국산업식품공학회 2010 산업 식품공학 Vol.14 No.1

Citrus계 식용 코팅제인 beeswax-hydroxypropyl methylcellulose(BW-HPMC), soybean oil-carboxymethyl cellulose(SBO-CMC), carnaubawax-shellac-locust bean gum (CW-SL-LBG)를 각각 사용하여 레몬에 먼저 1차 코팅하고 항산화제인 비타민 C와 E를 섞어 그 위에 제 2차 코팅하여 이중층의 multilayered 레몬을 제조하였다. 레몬 껍질 위에 형성된 막의 양은 CW-SL-LBG, BW-HPMC, SBO-CMC의 순으로 높게 나타났다. 가속 저장 실험 조건으로 30˚C의 항온기에 12일 동안 저장하면서 유자의 중량감소율, 부패율, 경도, pH, 가용성 고형분, 적정산도, 갈변도의 변화를 측정하고 관능검사를 실시하였다. 중량감소율, 부패율, 경도, 갈변도는 CW-SL-LBG가 가장 작은 변화를 보였고, pH, 가용성 고형분, 적정산도의 변화는 SBO-CMC가 가장 작게 나타났다. 저장성의 관능검사에서는 CW-SL-LBG가 가장 양호하게 나타났다. 결과적으로 CW-SL-LBG가 비타민 C와 E를 함유한 multilayer 코팅에 가장 적합한 물질로 평가되었다. Multilayer edible coatings was applied to lemon with beeswax-hydroxypropyl methylcellulose (BW-HPMC), soybean oil-carboxymethyl cellulose (SBO-CMC), and carnaubawax-shellac-locust bean gum (CW-SL-LBG), respectively. The multilayer was composed of two layers of the same material, but the outer layer only contained vitamins C and E as antioxidants. Coating amounts built on lemon peel were measured to be large in the order of CW-SL-LBG>BW-HPMC>SBO-CMC. The coated lemons were stored at 30˚C for 12 days. CW-SL-LBG showed the least change during the storage in weight loss, rotten rate, firmness, and browning. Whereas SBO-CMC had the least change in pH, soluble solid amount, and titratable acidity. In a sensory test, CW-SL-LBG was evaluated to be the best in the attributes such as spoilage, glossiness, color, firmness, and flavor. Overall CW-SL-LBG was judged to be the best for multilayerd coating with vitamin C and E on lemon.