PET/CT 검사에 있어서 MR Torso Coil의 CT 감쇄보정에 대한 영향 평가

이승재,반영각,오신현,강천구,임한상,김재삼,이창호,서수현,박용성,Lee, Seung Jae,Bahn, Young Kag,Oh, Shin Hyun,Gang, Cheon-Gu,Lim, Han Sang,Kim, Jae Sam,Lee, Chang Ho,Seo, Soo-Hyun,Park, Yong Sung 대한핵의학기술학회 2012 핵의학 기술 Vol.16 No.2

Purpose : Combined MR/PET scanners that use the MRI for PET AC face the challenge of absent surface coils in MR images and thus cannot directly account for attenuation in the coils. To make up for the weak point of MR attenuation correction, Three Modality System (PET/CT +MR) were used in Severance hospital. The goal of this work was to investigate the effects of MR Torso Coil on CT attenuation correction for PET. Materials and Methods : PET artifacts were evaluated when the MR Torso Coil was present of CTAC data with changing various kV and mA in uniformity water phantom and 1994 NEMA cylinderical phantom. They evaluated and compared the following two scenarios: (1) The uniform cylinder phantom and the MR Torso Coil scanned and reconstructed using CT-AC; (2) 1994 NEMA cylinderical phantom and the MR Torso Coil scanned and reconstructed using CT-AC. Results : Streak artifacts were present in CT images containing the MR Torso Coil due to metal components. These artifacts persisted after the CT images were converted for PET-AC. CT scans tended to over-estimate the linear attenuation coefficient when the kV and mA is increasing of the metal components when using conventional methods for converting from CT number. Conclusion : The presence of MR coils during PET/CT scanning can cause subtle artifacts and potentially important quantification errors. Alternative CT techniques that mitigate artifacts should be used to improve AC accuracy. When possible, removing segments of an MR coil prior to the PET/CT exam is recommended. Further, MR coils could be redesigned to reduce artifacts by rearranging placement of the most attenuating materials.

PET/CT 영상에서 조영제를 사용하지 않은 CT와 조영제를 사용한 CT를 이용한 감쇠보정에 따른 표준화섭취계수의 비교

이승재,박훈희,안샤론,오신현,남궁혁,임한상,김재삼,이창호,Lee, Seung-Jae,Park, Hoon-Hee,Ahn, Sha-Ron,Oh, Shin-Hyun,NamKoong, Heuk,Lim, Han-Sang,Kim, Jae-Sam,Lee, Chang-Ho 대한핵의학기술학회 2008 핵의학 기술 Vol.12 No.2

PET/CT 검사의 사용 초기에 CT는 주로 감쇠보정(Attenuation Correction: AC)의 목적으로 사용되어졌지만, CT의 성능이 향상됨으로써 조영제를 이용한 CT검사를 진단에 반영하여 보다 진보된 진단적 가치를 가질 수 있게 되었다. 조영제의 사용이 없이도 CT를 판독할 수 있지만 병변의 정확한 범위를 확인하고 정상 구조물을 구별하는데 있어서 조영제의 사용은 판독자로 하여금 판독을 매우 용이하게 하는 도움을 줄 수 있다. 하지만, 그동안 PET/CT검사 시 조영제가 감쇠보정에 영향을 줄 수 있다는 논쟁으로 이견이 많았다. 40-140 keV 정도의 낮은 엑스선을 이용하는 CT영상에 비하여, 조영제를 사용한 CT영상에서는 조영제로 인해 감쇠가 많이 되지만 511 keV의 에너지를 가진 감마선은 조영제로 인해 거의 영향을 받지 않게 되고 이로 인해 감쇠보정 시 과보정을 하게 되어 PET영상에서 오류를 나타낼 수 있다는 의견이 보고되기도 하였다. 이와는 반대로 조영제가 감쇠보정에 과대평가를 가져올 수 있다는 의견과 과보정으로 인한 표준화섭취계수에 변화의 가능성은 있으나 결정적인 영향을 미치지 않는다는 의견도 제시되었다. 본 연구에서는 조영제의 영향이 SUV에 어떠한 영향을 미치는지에 대해서만 비교 평가하였다. 2007년 12월에서 2008년 6월 사이에 본원에서 PET/CT 검사를 시행한 환자 중 요오드 조영제에 대한 부작용이 없고 당뇨병이 없는 진행성 암 환자 30명을 대상으로 하였으며, DSTe (General Electric Healthcare, Milwaukee, MI, USA)를 사용하여, 각각의 환자는 조영제를 사용하지 않은 CT를 시행한 후 PET영상을 얻었고 그 후, 조영제를 사용한 CT검사를 하였다. 각각의 CT정보로 감쇠보정을 실시, 종류별로 PET영상을 획득하여, 각 영상에 동일한 관심영역(Region of Interests : ROIs)을 설정 후, SUV를 비교 하였다. 얻어진 두 가지 결과 값의 정량 분석의 비교를 위해서 대응표본 T-검정 (Paired t-test)을 사용하였다. 검사를 시행한 30명의 환자에게서 폐, 간, 심장의 $SUV_{max}$ 값과 $SUV_{mean}$값을 측정하여 총 180개 영역을 분석하였다. 조영제를 사용하기 전과 후를 비교하였을 때, 측정한 거의 모든 영역에서 조영 후의 $SUV_{max}$와 $SUV_{mean}$가 상승하였고 통계적으로도 유의한 것으로 나타났다(p value<0.05). 심장 영역에서 조영 전 보다 조영 후의 $SUV_{mean}$값이 증가된 것으로 나타났지만, 통계적으로 유의하게 나타나지는 않았다. 조영제를 사용한 CT영상의 SUV값이 과보정되어, 조영제를 사용하지 않은 CT의 SUV 보다 높게 나왔으나 기존의 보고된 논문에서는 이와 같은 결과는 실제 임상 판독에 있어서 큰 영향을 미치지 않는다고 보고되어 있다. 그러나 원발성병변의 진행을 알아보는 과정에서는 SUV의 작은 변동도 분명 영향을 줄 수 있으므로 간 영역과 같이 SUV의 변동이 다른 영역에 비해 상대적으로 큰 영역에서는 수치의 변화에 대한 주의가 요구 될 것으로 사료된다. Purpose: At the beginning of PET/CT, Computed Tomography was mainly used only for Attenuation Correction (AC), but as the performance of the CT have been increase, it could give improved diagnostic information with Contrast Media. But it was controversial that Contrast Media could affect AC on PET/CT scan. Some submitted thesis' show that Contrast Media could overestimate when it is for AC data processing. On the contrary, the opinion that Contrast Media could be possible to affect the alteration of SUV because of the overestimated AC. But it does not have a definite effect on the diagnosis. Thus, the affection of Contrast Media on AC was investigated in this study. Materials and Methods: Patient inclusion criteria required a history of a malignancy and performance of an integrated PET/CT scan and contrast- enhanced CT scan within a 1-day period. Thirty oncologic patients who had PET/CT scan from December 2007 to June 2008 underwent staging evaluation and met these criteria. All patients fasted for at least 6 hr before the IV injection of approximately 5.6 MBq/kg (0.15 mCi/kg) of $^{18}F$-FDG and were scanned about 60 min after injection. All patients had a whole body PET/CT performed without IV contrast media followed by a contrast-enhanced CT on the Discovery STe PET/CT scanner. CT data were used for AC and PET images came out after AC. The ROIs drew and measured SUV. A paired t-test of these results was performed to assess the significance of the difference between the SUV obtained from the two attenuation corrected PET images. Results: The mean and maximum Standardized Uptake Values (SUV) for different regions averaged over all Patients. Comparing before using Contrast Media and after using, Most of ROIs have the increased SUV when it did Contrast Enhanced CT compare to Non-Contrast enhanced CT. All regions have increased SUV and also their p value was under 0.05 except the mean SUV of the Heart region. Conclusion: In this regard, the effect on SUV measurements that occurs when a contrast-enhanced CT is used for attenuation correction could have significant clinical ramifications. But some submitted thesis insisted that the percentage change in SUV that can determine or modify clinical management of oncology patients is small. Because there was not much difference that could be discovered by interpreter. But obviously the numerical change was occurred and on the stage finding primary region, small change would be base line, such as the region of liver which has greater change than the other regions needs more attention.

Radiation Exposure of Hands and Feet from $^{18}F$-FDG in Radio-technologists

이승재,정석,서수현,박용성,박훈희,오신현,임한상,김재삼,이창호,Lee, Seung-Jae,Jeong, Seok,Seo, Soo-Hyun,Park, Yong-Sung,Park, Hoon-Hee,Oh, Shin-Hyun,Lim, Han-Sang,Kim, Jae-Sam,Lee, Chang-Ho The Korean Society of Nuclear Medicine Technology 2011 핵의학 기술 Vol.15 No.2

Purpose: The radiation exposure from radioisotope at the hands and foots of radiation workers who works in PET/CT part at the department of nuclear medicine was investigated in this study. Materials and Methods: From 4th August 2010 to 14th January 2011, 6 radio-technologists' radiation on hands and feet were measured. All radio-technologist have been examined around 8; morning, 12; afternoon, and 16 o'clock; evening, respectively. SPSS version 17 was used for statistical analysis. Results: The statistical significances were calculated in several ways. The radiation from both hands and feet in the Morning was lower than Afternoon and Evening. In some cases, the detected radiation showed extremely high values in data. In order to find the effect of the ${\gamma}$-ray on the hand, the estimated doses were presumably calculated, however, the exposure dose on feet were unmeasured. Conclusion: Even if the radiation exposure from the radioisotope at the hands and feet were under the limitations, it is definitely needs to prevent the radiation-contamination. Therefore, the radio-technologists need to have a proper radiation-dealing-procedure of their own, and must try to prevent a radiation exposure by themselves.

The Study on the Dilution Time of Radioactive Tracer in Estradiol Measurement

이승재,서수현,이성하,박용성,오기백,김재삼,Lee, Seung Jae,Seo, Soo Hyun,Lee, Sung Ha,Park, Yong Sung,Oh, Ki Baek,Kim, Jae Sam The Korean Society of Nuclear Medicine Technology 2017 핵의학 기술 Vol.21 No.2

Purpose The high-dose administration of I-131 has been standing for the basic therapy method of thyroid cancer. In korea, it is not necessary for patients to be hospitalized if the administration dose are under 1.2 GBq. However, if the dose are over 1.2 GBq, the patients should be stay in special ward with radiation shield. In such cases, the radioactivity level upon release should be under a dose of $70{\mu}Sv/hr$ at a distance of approx. 1m. This regulation bring the patients to stay for about 2 to 3 days in ward before the release. Materials and Methods Using the inpatients' release data of severance hospital, an inpatient-days were retrospectively calculated and compared with practical data and estimate the inpatient-days with the conditions of korea ($70{\mu}Sv/hr$), Japan ($30{\mu}Sv/hr$), germany ($3.5{\mu}Sv/hr$ at a distance of approx. 2 m), and other european countries. Results When a effective half-life of 15.4 was used, the expected inpatient-days were calculated as 2.15 days in the condition of Japanese regulation and 1.37 days in the condition of korean regulation. The practical inpatient-days of patients in Severance hospital were 1.32 days. Conclusion As ICRP 94 has been mentioned that the release of patients administrated with I-131 for the therapy should be carefully considered because each patients has different thyroid uptake rate and their conditions with family members after the release from the ward. Nonetheless, efforts to bring more aquate data which is for getting closer to the practical data should be continuously studied.

An Elimination of False-Positive I-131 Sites in Esophagus for Thyroid Carcinoma; Using Water with Vitamin C Dissolved

이승재,박훈희,안샤론,조석원,최영숙,조응혁,김재삼,이창호,Lee, Seung-Jae,Park, Hoon-Hee,Ahn, Sa-Ron,Cho, Seok-Won,Choi, Young-Sook,Cho, Arther,Kim, Jae-Sam,Lee, Chang-Ho The Korean Society of Nuclear Medicine Technology 2008 핵의학 기술 Vol.12 No.1

Purpose: Whole body imaging with radioiodine can detect functioning metastases. Non-physiologic I-131 uptake detected on images usually is interpreted as suggesting functioning thyroid metastases. However, extra-thyroidal I-131 accumulation does not always imply thyroid cancer metastases and has been reported in many circumstances. In order to avoid unnecessary therapeutic interventions it is important to distinguish false-positive sites of I-131 localization. We study here to remove false-positive sites around esophagus region on I-131 whole body imaging in patients who were administrated thyroidectomy. Materials and Methods: From April to August in 2007, we had the patients who had visited our department after they received thyroidectomy due to thyroid cancer. They were given I-131, and performed radioiodine body scan after 41 to 50 hours. Patients were whole-body-scanned for the speed of 8 cm per minute. After that, we took anterior and posterior static images around the patients' neck measured by 300 thousand counts per image. We selected 44 patients who had hot spots around neck region, we divided the patients into two groups. One group was given 0.5 L of water and the other group was given 0.5 L of water with 1 g of Vitamin C dissolved. The patients were asked to drink the fluid for one minute in sitting position and after that, we measured 300 kilo counts per image again. We compared prior anterior, posterior static images with anterior, posterior images after the patients had water or water that Vitamin C resolved. Results: In using water, both observer 1 and 2 interpreted 6 patients were washed out. In the water with Vitamin C resolved, observer 1 and 2 interpreted 9 and 8 patients were washed out. Observer 1 and 2 interpreted 6 and 5 patients had 'indeterminate' when they used water. Both observer 1 and 2 interpreted 6 patients had 'indeterminate' when they used water with Vitamin C resolved. When they used water, observer 1 interpreted 10 patients had 'unchanged' and observer 2 interpreted 11 patients had 'unchanged'. Differently, when they used water with vitamin C resolved, observer1 had 8 patients having 'unchanged'and observer 2 had 9. Conclusion: As a result, by making patients drink 0.5 liter of water which has vitamin C resolved helped getting rid of false-positive sites in esophagus. Therefore, based on this study, we believe that drinking water with vitamin C dissolved is very in terms of reducing false-positive hot spot around the esophagus for the iodine-131 whole body scan.

채제공 「정원록」 연구

이승재 ( Lee Seung-jae ) 근역한문학회 2018 한문학논집 Vol.50 No.-

In the 18th century Seoul was becoming a modern city and an unworldly and aesthetic Chinese culture was prevalent, so it was popular for the nobility to get together to write poems. Among each political assembly, one of the Southerners, Jae-Gong Chae led a group of poetry writers several times. Jungwonrok consists of poems written by Jong-Nam Assembly, which lasted from fall to winter in 1773. The gathering was special to Jae-Gong Chae, so he left a prologue later with details of the attendance of the members, and this was evidence showing the changes of the character of the assembly. Also, several poems focusing on learning were written by Jong-Nam Assembly which couldn't be found previously, and this showed that Jong-Nam Assembly was the gathering to write poems with a special purpose. Six of the members passed a state examination within a few years after joining Jong-Nam Assembly and this result was a significant achievement. Jong-Nam Assembly was a good example of Jae-Gong Chae using the gathering as a tool for Southerners' solidarity and entering politics.

중국의 도로건설 현황 및 계획

이승재,이상우,권영인,Lee, Seung-Jae,Lee, Sang-U,Gwon, Yeong-In 한국도로교통협회 2005 도로교통 Vol.102 No.-

A Study on Tourists Information and Language Transference

이승재,Lee, Seung Jae The Society of Digital Policy and Management 2014 디지털융복합연구 Vol.12 No.5

본 논문에서는 관광의 1차적인 정보원으로서의 홈페이지와 관광홍보물의 언어학적 전환의 특징을 살펴보고자 한다. 즉 관광관련 사이트의 한국어 원문과 영어 번역물을 비교하면서 관광정보 텍스트가 올바르게 언어전환 되었는지 점검하고 나아가 전환된 영어번역물과 한국어 원문을 대조하면서 번역물에서 발생하는 언어규약과 의사소통의 특징을 살펴본다. 특히 한국어와 영어는 언어유형에서 대조적인 언어로서 번역을 통해 전환되었을 때 특이한 담화의 양상을 보인다. 즉 한국어에 비해 영어표현은 직설적이고 우회적인 표현을 피하는 경향이 있다. 또한 영어번역본에서는 영어 화자위주로 언어가 변형되어 표현됨을 주시할 수 있다. 이것은 영어를 사용하는 언어군에서 흔히 발생하는 양상으로 광의의 문화간의 차이로 간주될 수 있다. 따라서 외국관광객의 1차적 정보원으로서의 관광웹사이트는 관광정보를 제공하는 동시에 목적지의 문화를 간접적인 형태로 표현함으로써 사회적 이미지 형성과 문화간 차이를 대변하며 커뮤니케이션의 일환으로서 공손의 원칙과 Grice의 원칙을 준수하고 있다. The purpose of this paper is to examine website information as well as promotional texts comparing source texts of Korean with translated versions of English, and drew characteristics of tourism texts from a discourse and communicative perspective. This study shows that the website or promotional texts is the first source of information in tourism, which is most referred to by the in-bound tourists, and the information given by the official homepage is most trustful content of Korean tourism. With comparison of source text of Korean with the translated English version, this paper shows that Korean source texts have a tendency to prefer the longer explication and more detailed information on the scenic spots and attractions than the English translations. When it is translated into English, the translated version does not follow the literal way of translation, and is segmented for reader's understanding and adapted following the target language's communicative conventions and the target culture. Consequently, this study supports the adaption in tourism promotional English translation, and ensures that the communicative constraints of tourism, that is, politeness and Grician maxims are preserved even in the written form of communication, translation.

사군자탕(四君子湯), 이진탕(二陳湯) 및 육군자탕(六君子湯)이 고지혈증(高脂血症)에 미치는 영향(影響)

이승재,문병순,김세길,Lee, Seung-Jae,Mun, Byeong-Sun,Kim, Sae-Gil 대한한방내과학회 1994 대한한방내과학회지 Vol.15 No.1

The present experiments were designed to investigate the effect of Ijntang, Sagoonjatang, and Yuggoonjatang on the hyperlipidemia induced rabbit. In order to control the precise chemical and physical condition, the experimental rabbits were supplied with calory limited food. The Hyperlipidemia rabbits were induced by oral administration of cholesterol (250mg/kg) for 4 weeks. The results were as followings : 1. The hyperlipidemia (control) group increased the concentration of serum glucose to $204.1{\pm}2.63\;mg/dl$ at the 4th. week, however, the other drug administrated groups such as Ijintang, Sagoonjatang, and Yuggoonjatang decreased significantly. 2. The control group increased the concentration of serum totalcholesterol to $299.0{\pm}4.18\;mg/dl$ at the 4th. week, however, the other drug administrated groups Ijintang, Sagoonjatang, and Yuggoonjatang decreased significantly. 3. The control group increased the concentration of serum total lipid to $429.1{\pm}1.72\;mg/dl$ at the 4th. week, however, the other drug administrated groups such as Ijintang, Sagoonjatang, and Yuggoonjatang decreased significantly. 4. The control group increased the concentration of serum triglyceride to $149.3{\pm}3.01\;g/dl$ at the 4th. week, however, the other drug administrated groups such as Ijintang, Sagoonjatang, and Yuggoonjatang decreased significantly. 5. The control group increased the concentration of serum HDL-cholesterol to $83.0{\pm}1.09$\;mg/dl$ at the 4th. week, and, the other drug administrated groups such as Ijintang, Sagoonjatang, and Yuggoonjatang increased significantly. 6. The lipid deposition to the aortic endothelium decreased more at the Yuggoonjatang group than the other groups. According to the above experimental results, Yuggoonjatang is assumed to have a more curative effect against hyperlipidemia than the other drug such as Ijintang and Sagoonjatang.

Estimation of Plastic Energy Dissipation Amount of Multi-bent Spatial structure by Equivalent Linear Analysis

이승재,Lee, Seung-Jae Korean Association for Spatial Structures 2006 한국공간구조논문집 Vol.6 No.2

It is important to evaluate energy absorption capacity of frames required during a design earthquake. An inelastic computer analysis based on mathematical modelling of energy absorbing frames and elements makes it possible to evaluate required energy absorption capacity. But such an analysis sometimes consumes much computation time particularly in case of complicated structural system. This paper presents a proposal to predict energy absorption of multi-bent steel frames by simple equivalent linear method.