PET/CT 검사에서 주입선량의 변화에 따른 적정한 영상획득시간의 평가

김창현,이현국,송치옥,이기흔,Kim, Chang Hyeon,Lee, Hyun Kuk,Song, Chi Ok,Lee, Gi Heun 대한핵의학기술학회 2014 핵의학 기술 Vol.18 No.2

PET/CT검사는 장비의 발전과 더불어 환자의 피폭을 줄이기 위하여 저 선량을 사용하는 추세에 있다. 이에 PET/CT scanner의 영상의 질을 유지하기 위하여 주입선량의 변화에 따른 적정한 bed당 획득시간을 평가하고자 한다. 모형 실험은 NEMA NU2-1994 phantom으로 hot cylinder의 농도를 3, 4.3, 5.5, 6.7 MBq/kg 으로 증가시키고 bed당 획득시간을 30 sec, 1 min, 1 min 30 sec, 2 min, 2 min 30 sec, 3 min, 3 min 30 sec, 4 min, 4 min 30sec, 5 min, 5 min 30 sec 10 min, 20 min, 30 min로 늘려가며 영상을 획득 후 hot cylinder의 농도와 배후 방사능에 4개의 ROI (Region of Interest)을 설정하고 hot cylinder의 농도 와 bed당 획득시간에 따른 변화를 최대 표준섭취계수(Standard Uptake Value maximum, $SUV_{max}$)를 측정 후 신호 대 잡음비(Signal to Noise Ratio, SNR), BKG (Background)의 표준편차를 계산하여 비교해 보았다. 또한 4.3 MBq phantom을 이용하여 검사 대기시간의 변화(15분과 1시간)에 따른 각각의 $SUV_{max}$, SNR, BKG의 표준편차를 비교하였다. 단위 질량당 방사능의 농도가 3, 4.3, 5.5, 6.7 MBq으로 증가하고 또한 각 농도의 time/bed을 1분30초에서 30분까지 늘렸을 때 hot cylinder의 $SUV_{max}$ 값은 bed당 획득시간이 각 방사능의 농도에 따라 30초에서 2분까지는 최대 18.3에서 최소 7.3까지 변화가 심했고 2분 30초에서 30분까지는 최대 8에서 최소 5.6으로 일정한 $SUV_{max}$ 값을 나타내었다. 단위 질량당 방사능의 변화에 따른 SNR은 3 MBq에서는 최소 0.41에서 최대 0.49까지 일정하였고 4.3 MBq과 5.5 MBq에서는 각각 최소 0.23, 0.39에서 최대 0.59, 0.54로 bed당 획득시간이 늘수록 상승하였다. 방사능 농도 6.7 MBq에서는 30초에서 최대 0.59로 높았지만 이후 0.43에서 0.53으로 일정하게 유지하였다. BKG (Background)의 표준편차는 3 MBq에서 2분 30초 후부터 0.38에서 0.06으로 낮아졌고 4.3 MBq과 5.5 MBq에서는 1분 30초 후부터 0.38에서 0으로 낮아졌고 6.7 MBq에서는 30초에서 30분 전 구간에서 낮은 0.33에서 0.05이었다. 4.3 MBq 팬텀으로 검사대기시간을 15분과 1시간으로 변화시킨 결과에서는 bed당 획득시간이 2분 30초부터 $SUV_{max}$값이 서로 일정한 값을 보였고 SNR은 1분 30초부터 비슷한 값을 보였다. 위 결과와 같이 단위 질량당 주입된 방사능의 농도를 3, 4.3, 5.5, 6.7 MBq으로 증가시켰을 때 bed당 획득시간이 2분 30초 이상에서는 $SUV_{max}$와 SNR의 값이 서로 일정하게 유지되고 검사 대기시간의 변화(15분과 1시간)에서도 bed당 획득시간이 2분 30초 이상에서는 $SUV_{max}$와 SNR의 값이 일정하게 유지되는 것을 알 수 있었다. 이 NEMA NU2-1994 phantom 실험의 결과에서 주입되는 방사능의 농도의 변화에도 일정한 $SUV_{max}$와 SNR의 값을 구하기 위한 최소 bed당 획득시간은 2분 30초이라는 것을 알 수 있었다. 하지만 이 획득시간은 장비의 사양과 특성에 따라 차이가 있을 수 있다. Purpose There is the recent PET/CT scan in tendency that use low dose to reduce patient's exposure along with development of equipments. We diminished $^{18}F$-FDG dose of patient to reduce patient's exposure after setting up GE Discovery 690 PET/CT scanner (GE Healthcare, Milwaukee, USA) establishment at this hospital in 2011. Accordingly, We evaluate acquisition time per proper bed by change of infusion dose to maintain quality of image of PET/CT scanner. Materials and Methods We inserted Air, Teflon, hot cylinder in NEMA NU2-1994 phantom and maintained radioactivity concentration based on the ratio 4:1 of hot cylinder and back ground activity and increased hot cylinder's concentration to 3, 4.3, 5.5, 6.7 MBq/kg, after acquisition image as increase acquisition time per bed to 30 seconds, 1 minute, 1 minute 30 seconds, 2 minute, 2 minutes 30 seconds, 3 minutes, 3 minutes 30 seconds, 4 minutes, 4 minutes 30 seconds, 5 minutes, 5 minutes 30 seconds, 10 minutes, 20 minutes, and 30 minutes, ROI was set up on hot cylinder and back radioactivity region. We computated standard deviation of Signal to Noise Ratio (SNR) and BKG (Background), compared with hot cylinder's concentration and change by acquisition time per bed, after measured Standard Uptake Value maximum ($SUV_{max}$). Also, we compared each standard deviation of $SUV_{max}$, SNR, BKG following in change of inspection waiting time (15minutes and 1 hour) by using 4.3 MBq phantom. Results The radioactive concentration per unit mass was increased to 3, 4.3, 5.5, 6.7 MBqs. And when we increased time/bed of each concentration from 1 minute 30 seconds to 30 minutes, we found that the $SUV_{max}$ of hot cylinder acquisition time per bed changed seriously according to each radioactive concentration in up to 18.3 to at least 7.3 from 30 seconds to 2 minutes. On the other side, that displayed changelessly at least 5.6 in up to 8 from 2 minutes 30 seconds to 30 minutes. SNR by radioactive change per unit mass was fixed to up to 0.49 in at least 0.41 in 3 MBqs and accroding as acquisition time per bed increased, rose to up to 0.59, 0.54 in each at least 0.23, 0.39 in 4.3 MBqs and in 5.5 MBqs. It was high to up to 0.59 from 30 seconds in radioactivity concentration 6.7 MBqs, but kept fixed from 0.43 to 0.53. Standard deviation of BKG (Background) was low from 0.38 to 0.06 in 3 MBqs and from 2 minutes 30 seconds after, low from 0.38 to 0 in 4.3 MBqs and 5.5 MBqs from 1 minute 30 seconds after, low from 0.33 to 0.05 in 6.7 MBqs at all section from 30 seconds to 30 minutes. In result that was changed the inspection waiting time to 15 minutes and 1 hour by 4.3 MBq phantoms, $SUV_{max}$ represented each other fixed values from 2 minutes 30 seconds of acquisition time per bed and SNR shown similar values from 1 minute 30 seconds. Conclusion As shown in the above, when we increased radioactive concentration per unit mass by 3, 4.3, 5.5, 6.7 MBqs, the values of $SUV_{max}$ and SNR was kept changelessly each other more than 2 minutes 30 seconds of acquisition time per bed. In the same way, in the change of inspection waiting time (15 minutes and 1 hour), we could find that the values of $SUV_{max}$ and SNR was kept changelessly each other more than 2 minutes 30 seconds of acquisition time per bed. In the result of this NEMA NU2-1994 phantom experiment, we found that the minimum acquisition time per bed was 2 minutes 30 seconds for evaluating values of fixed $SUV_{max}$ and SNR even in change of inserting radioactive concentration. However, this acquisition time can be different according to features and qualities of equipment.

보조호르몬요법을 받는 여성 유방암 환자의 모발 변화와 치료 실태에 대한 기초 연구

이재경 ( Jae Kyung Lee ),김창현 ( Chang-hyun Kim ),홍동균 ( Dongkyun Hong ),정경은 ( Kyung Eun Jung ),서영준 ( Young-joon Seo ),김창덕 ( Chang-deok Kim ),이진선 ( Jin Sun Lee ),권인선 ( In Sun Kwon ),박상현 ( Sanghyun Park ),이영 대한피부과학회 2021 대한피부과학회지 Vol.59 No.7

Background: Hormone therapy, which includes tamoxifen and aromatase inhibitors, is the most common adjuvant therapy used for breast cancer. However, only a few studies have reported endocrine therapy induced alopecia. Objective: We investigated the effects of long-term adjuvant hormone therapy on hair in patients with breast cancer, in addition to patients’ concerns and current treatment for hair loss. Methods: Patients completed a questionnaire that included information on self-perceived hair changes after each adjuvant therapy session, distress, and current treatment for hair loss. Using a folliscope, we measured hair density and thickness in each patient and in healthy controls. Results: The study included 93 patients with breast cancer (mean age 51.9±9.8 years). The density and hair thickness were 106.36±21.85 hairs/cm2 and 0.07±0.01 mm in the patient group and 147.86±30.67 hairs/cm2 and 0.07±0.01 mm in the control group (n=98, mean age 52.10±8.40 years), respectively. The mean hair density was significantly lower in the patient group than in the control group; however, no statistically significant intergroup difference was observed in hair thickness. Among 76 patients who perceived hair changes after adjuvant therapy, 71.1% (n=54) were distressed with regard to hair changes. However, only 7.8% of the patients, including two who were treated by dermatologists, currently received treatment for hair changes. Conclusion: Dermatologists should be familiar with hair changes in patients with breast cancer and provide appropriate education to encourage patients to consult dermatologists for hair loss and thinning after breast cancer treatment. (Korean J Dermatol 2021;59(7):521∼526)

후두하 신장운동이 두경부자세와 흉쇄유돌근 및 승모근 활성에 미치는 영향

김창현,한경수,현태연,Kim, Chang-Hyun,Han, Kyung-Soo,Hyun, Tae-Yeon 대한안면통증구강내과학회 2000 Journal of Oral Medicine and Pain Vol.25 No.1

This study was performed to investigate the effect of suboccipital stretch on the head and neck posture and the electromyographic(EMG) activity of some cervical muscles. For this study, 39 patients with temporomandibular disorders(TMD) and 34 dental students without any signs and symptoms in the masticatory system were selected as the patients group and as the normal group, respectively. Head position by goniometer CROM$^{(R)}$(Performance attainment, St. Paul, USA), EMG activity by BioEMG$^{(R)}$(Bioresearch Inc., Milwaukee, USA), and craniocervical posture by cephaloradiography were observed in both natural head posture(NHP) and head posture with suboccipital stretch(tuck posture) abtained from slight posteroinferior finger pressure on the chin. Variables measured on the cephaloradiograph were SN angle, atlas angle, CVT angle, occiput-atlas and atlas-axis distance, and pharyngeal width. The data obtained were analysed by SPSS windows program and the results of this study were as follows : 1. In the sagittal plane, degree of anterior rotation of the head by suboccipital stretch was 6.3 in the patients group, and 6.2 in the normal group, respectively. So there was no significant difference between the two groups for degree of anterior rotation, but the position of the head in the patients group were more posteriorly extended than in the normal group in both NHP and tuck posture. 2. EMG activity of the stemocleidomastoideus in the patients group, and that of the upper trapezius and the sternocleidomastoideus in the normal group were increased by suboccipital stretch. The range of EMG activity, however, in these cervical muscles were 1.6 -2.3)u.V. 3. Cephalometric variables such as SN angle, atlas angle, CVT angle, occiput-atlas and atlas-axis distance except pharyngeal width were generally increased by suboccipital stretch. There was some difference, however, in results between the two groups. Atlas angle was not changed in the patients group whereas CVT angle was not changed in the normal group. 4. The distance from subocciput to spinous process of axis was significantly increased as much as 3.0mm in the patients group, and 3.7mm in the normal group by suboccipital stretch.

고려중기 윤언이의 사상과 파주 金剛齊

김창현(Kim Chang hyun) 경인교육대학교 기전문화연구소 2004 기전문화연구 Vol.31 No.-

고려중기 예종과 인종 때는 문종 때 완성된 체제가 흔들려 변화를 모색하는 시기였는데, 이 시기에 관직활동을 한 윤언이는 정치가이자 문사로서 중요한 역할을 수행하였다. 북송은 선종과 도교가 유행하고, 유교ㆍ선종ㆍ도교의 교류가 활발해 신유학이 등장했는데 고려도 그 영향을 받아 비슷한 경향을 띠었다. 윤언이는 정지상과 함께 송의 신법을 받아들여 민생안정과 부국강병을 추진하였고 칭제건원을 통해 국가의 위신을 세우려 하였지만, 정지상과 묘청의 서경천도 운동에는 참여하지 않았다. 윤언이와 김부식은 정치적으로 사상적으로 대립하였다. 김부식은 사마광을 모범으로 삼아 옛 체제를 고수하려 한 반면 윤언이는 왕안석의 사상을 받아들여 새로운 체제를 만들려 하였는데, 이는 『주역』의 해석을 둘러싼 갈등으로 표출되었다. 조종의 舊制에 대해 김부식은 완전한 것으로 받아들인 반면 윤언이는 현실에 맞게 고쳐야 한다고 생각했던 것이다. 이러한 면은 둘의 불교관에 반영되어 의천의 사후 천태종이 약화되면서 김부식은 화엄종에 관심을 가진 반면 윤언이는 선종을 선호하였다. 윤언이는 북송 신유학을 받아들였을 뿐만 아니라 선종과 도가에도 심취하였는데, 그가 『주역』에 정통한 것이 도가와 신유학에 접근하는 촉매로 작용하였다. 그는 儒者로서 불ㆍ도에 심취해 유ㆍ불ㆍ도의 일치를 이루어냈던 것인데 그 중심에 파주 금강재가 있었다. 그는 선종과 도가를 좋아하면서도 현실을 도피하지 않고 변혁을 추구하다가 묘청의 섣부른 정변의 결과 안정을 중시하는 김부식 세력에 패배해 좌절하였다. 하지만 금강재에서 금강거사로서 선종의 부흥에 공헌하였으며, 의종초의 개혁을 주도해 어느 정도 성과를 거두고 原始反終 하였다. People in the period of King Yejong and King Injong in the middle of Koryeo pursued changing the system completed by King Munjong. At that time Yun Eonyi who worked for the government service after passing the state examination played a important role as a politician and literary man. In Northern Sung, Buddhism, Taoism and Confucianism were exchanged actively and as a result Neo-Confucianism appeared. This had influence on Koryeo to have such a tendency. Yun Eonyi and Jeong Jisang worked for the stabilization of the people s livelihood and wealth and military strength of the dynasty with receiving the new thought of Wang Anseok in Northern Sung and tried to enhance national prestige through assuming the title of emperor and using the name of an era. Jeong Jisang took the initiative in the movement of transferring the capital to Seogyeong with Myocheong, but Yun Eonyi seemed not to participate in that movement. Yun Eonyi well acquainted with the Book of Changes not only accepted Neo-Confucianism of Northern Sung, but also was infatuated with Zen Buddhism and Taoism. He approached Taoism through the Book of Changes. Yun Eonyi and Jeong Jisang as Confucian scholars were enthusiastic admirers of Buddhism and Taoism and harmonized Confucianism with Buddhism and Taoism. Though they admired Zen Buddhism and Taoism, they tried to make a reformation without escaping from reality. Their reformation failed because Myocheong who carried out a coup d etat was defeated by group of Kim Bushik taking a serious view of stability.

AS/RS 플랫폼 기반 컨테이너 장치장을 위한 리마샬링에 관한 연구

김창현,최상희,서정훈,배종욱,Kim, Chang-Hyun,Choi, Sang-Hei,Seo, Jeong-Hoon,Bae, Jong-Wook 한국시뮬레이션학회 2010 한국시뮬레이션학회 논문지 Vol.19 No.2

Due to the recent technological advance, new types of AS/RS which can handle containers are being developed, and it is expected that they will be applied to related industries before long. Some companies and institutes in our country have constructed pilot systems for high-density-high-stacking systems and tested them to develop AS/RS-typed warehouses for containers. Along with this kind of construction efforts, development of rules to operate such systems efficiently and safely is also important. When outward-bound shipment is scheduled in container port, re-marshalling which rearranges containers in the yard to make shipment easy is conducted. In this paper, operating rules for the re-marshalling as well as simulation experiments to evaluate the performance of the rules are presented. We suggested two kinds of alternative sets of operating rules for re-marshalling and described the relevant logics corresponding to all possible cases for each alternative of operating rules. Through various simulation experiments, we found that each alternative has the merits and demerits at the same time and we could not say the one is always superior to the other. As a useful strategy, changing the applying operating rule is recommended from moment to moment depending on the expected number of operations at the landside input/output position.

배합비의 탄생, 그리고 그 역사

김창현,Kim, Chang-Hyeon 한국단미사료협회 2006 피드저널 Vol.4 No.3

가축의 건강을 유지시키면서 고기, 젖, 알 등의 생산능력을 최대한으로 발휘시키려면 그들이 공급받는 사료 속에 가축이 필요로 하는 영양소가 부족하지 않아야 한다. 단미사료에는 완전한 영양균형이 되어 있는 것이 없기 때문에 이것만으로는 필요로 하는 모든 영양소를 공급시킬 수 없으므로 사양표준에 의하여 가축이 요구하는 영양소를 몇 종류의 사료로 배합하여 급여해야 한다. 그렇게 하기 위해서는 먼저, 여러 가지 원료사료의 영양소함량을 알아야하며, 각종 단미사료의 특징, 즉 기호성, 부피, 유독성 물질의 함유 여부, 배합공정상의 입자도 등을 고려하여 사료를 잘 배합하여야 한다. 이때 어떤 원료 사료를 얼마만큼씩 배합할 것인가를 결정하는 계산과정을 사료배합(feed formulation)이라하며 계산에 의하여 나온 결과를 사료배합비(feed formula)라고 한다. 최첨단의 사육 및 사료배합기술에 의해 현대의 축산업은 그 어느 때보다 완벽한 사료를 사용하며 생산량을 증대해 왔다. 그래서 본 글에서는 오늘날의 사료가 있도록 한 배합비의 탄생과정에 대해 간단히 설명하고자 한다.

유해인자별 노출실태 및 분석방법 19 - 시료 포집매체에 따른 일부사업장의 톨루엔 농도 비교

김창현,임성국,최호춘,Kim, Chang-Hyeon,Im, Seong-Guk,Choe, Ho-Chun 대한산업보건협회 2013 산업보건 Vol.299 No.-

Future Challenges and Opportunities of the Semiconductor Industry

김창현,Kim, Chang-Hyun The Institute of Electronics and Information Engin 2007 전자공학회지 Vol.34 No.7

아핀 집합의 특성을 이용한 변형된 PID 제어기의 최적 동조

김창현,임동균,서병설,Kim Chang-Hyun,Lim Dong-Kyun,Suh Byung-Sulh 대한전자공학회 2005 電子工學會論文誌-SC (System and control) Vol.42 No.6

In this paper, we propose a PID-PD controller and its tuning method to be modified form of PID controller that consist of the affine set of PID and PI-PD controller by analyzing relation between these controllers. The proposed tuning method controls the closed-loop system to locate between the step responses of system controlled by PID and PI-PD controller. The controller is designed by the optimum tuning method to minimize the proposed specific cost functions. Its effectiveness is examined by the case studies and their analysis. 본 논문에서는 PID 제어기와 PI-PD 제어기 사이의 관계를 분석하여 이 두 제어기의 affine 집합을 구성하는 PID 제어기의 변형된 형태인 PID-PD 제어기와 그 동조 방법을 새롭게 제안한다. 제안된 설계 방법은 PID와 PI-PD 제어기를 이용한 전체 폐루프 시스템인 시간 응답을 경계로 그 사이의 응답을 보이도록 설계할 수 있다. 그 동조 방법으로 특정한 가격함수를 선정하여 이를 최소화하는 최적 동조법을 적용하여 제어를 설계하였다. 제안된 제어기의 유용성을 사례 연구와 분석을 통해 검토했다.

원자로 비상노심냉각수 여과장치 개발 및 향후 전망

김창현,Kim, Chang-Hyeon 대한전기협회 2013 전기저널 Vol.- No.435