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동적신장검사에서 저선량을 사용한 신장검사의 재현성 평가
이재상,이규찬,이승환,배성복,박종엽,Lee, Jaesang,Lee, Kyuchan,Lee, Seunghwan,Bae, Seongbok,Park, Jongyeop 대한핵의학기술학회 2016 핵의학 기술 Vol.20 No.1
동적신장검사는 신장기능을 영상화하는 대표적인 방법이다. 동적신장검사에서 저선량 방사성의약품의 사용으로 기존 동적신장검사와 저선량을 사용한 신장검사의 비교를 통한 동적신장검사의 재현성을 평가해 보기로 했다. 본 비교실험을 통해 재현성이 우수할 경우 환자에 투여하는 방사선량을 줄인 동적신장검사법을 활용하고 환자의 피폭을 줄이고자 한다. 감마카메라 장비로는 Orbiter, SymbiaE (Siemens, Germany)를 사용하였고, 2013년 1월부터 2014년 2월까지 370 Mbq (10mCi)을 사용한 환자와 동일 환자 중 2014년 3월부터 2015년 7월까지 185 Mbq (5 mCi)을 사용한 환자를 대상으로 $^{99m}Tc-DTPA$사용 검사 21명과 $^{99m}Tc-MAG_3$사용 검사 20명 총 41명을 대상으로 데이터를 선별하였다. 결과 영상의 Renogram에서 Peak 지점의 프레임을 선택하여 신장의 관심영역과 배후방사능의 관심영역을 설정하고 K/B ratio를 구하여 비교하였다. $^{99m}Tc-DTPA$를 사용한 검사에서 370 Mbq을 사용하였을 때의 K/B ratio는 평균 $5.67{\pm}0.8$이었고, 185 Mbq을 사용하였을 때는 평균 $5.62{\pm}0.87$로 큰 차이를 보이지 않았다. $^{99m}Tc-MAG_3$를 사용한 검사에서도 신장/배후방사능 비는 370 Mbq을 사용 시 평균 $14.95{\pm}2.58$과 185 Mbq을 사용 시 평균 $14.56{\pm}2.02$로 큰 차이를 보이지 않았다. Paired sample t-test결과 p-value는 $^{99m}Tc-DTPA$ 0.566, $^{99m}Tc-MAG_3$ 0.363로 같은 비교집단 간 차이점이 없음을 확인하였다. 동일 환자를 대상으로 선량을 370 Mbq에서 185 Mbq로 줄였을 때의 동적신장검사의 재현성은 우수한 것으로 확인 되었다. 저선량 동적신장검사는 기존 감마카메라의 성능 개선 없이 재현성이 우수한 결과를 얻을 수 있고 환자의 피폭 또한 줄일 수 있을 것으로 사료된다. Purpose Dynamic kidney scan is a typical imaging technique that visualizes kidney function. Reproducibility of dynamic kidney scans has been evaluated by comparing low-dose kidney scans with low-dose radiopharmaceutical and standard dynamic kidney scan. With this comparative study, if reproducibility is superb, the dynamic kidney scan method with reduced radioactivity to patients is to be utilized and radiation exposure to patient is to be reduced. Materials and Methods For gamma camera, Orbiter, SymbiaE (Siemens, Germany) was used. Among patients who had used 370 Mbq (10 mCi) from January of 2013 to February 2014 and other patients who had used 185 Mbq (5 mCi) from March of 2014 to July of 2015 with identical condition, 21 subjects using DTPA and 20 subjects using $MAG_3$, 41 subjects in total, had been selected as subjects for data. From renogram of the result image, frame of the peak point was selected. Then, region of interest of kidney and background had been selected and Kidney to Background Ratio has been calculated for comparison. Results In tests using DTPA, kidney to background ratio when using 370 Mbq was $5.67{\pm}0.8$ at average while it was $5.62{\pm}0.87$ when using 185 Mbq, which didn't show much difference. Also in the tests using $MAG_3$, kidney to background ratio when using 370 Mbq was $14.95{\pm}2.58$ at average and $14.56{\pm}2.02$ in 185 Mbq, which neither showed much difference. In paired sample t-test, p-value was 0.566 in DTPA and 0.363 in $MAG_3$, which confirmed that there was no difference between the groups. Conclusion In identical patients, when dose was decreased from 370 Mbq to 185 Mbq, reproducibility of dynamic kidney scan was proven to be excellent. Low-dose Dynamic kidney scan can achieve results with fine reproducibility without improvement in performance of gamma camera and is expected to reduce radiation exposure to patient.
이재상,구상모,이상렬,Lee, Jae-Sang,Koo, Sang-Mo,Lee, Sang-Yeol 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.9
The TFTs have been fabricated with 3 different geometry SID electrodes which have the same channel W/L ratio (W/L = 5) due to constant channel resistance, The 3 samples have different channel widths (350, 150, and 25 ${\mu}m$) and channel lengths (70, 30, and 5 ${\mu}m$) by fixed channel W/L ratio simultaneously on one chip for reliable comparisons. Resultant on-current and field effect mobility are proportional to the channel width, while the subthreshold swing is inversely proportional to the channel width mainly due to the change of contact resistance. These results show that the contact resistance strongly affects the device performances and should be considered in the applications.
한국의 신생아에서 선천성 대사이상 Screening에 관한 역학조사
이재상,최철석,최규순,이무주,두화선,강상훈,Lee, Jae-Sang,Choi, Cheol-Seok,Choi, Kyu-Soon,Lee, Mu-Ju,Doo, Hwa-Sun,Kang, Sang-Hoon 한국생명보험의학회 1999 保險醫學會誌 Vol.18 No.-
The disorders of congenital metabolic errors causing mental retardation can be prevented by early diagnosis and treatment. We analysed 144,000 neonatal blood samples for phenyketonuria(PKU), maple syrup urine disease(MSUD), homocystinuria(HCU) and histidinuria(HE) by bacterial inhibition method, and galactosemia(GAL) by Paigen method. In our survey, the positive were 4 samples in PKU(4mg/dl;2, 6mg/dl;1, 8mg/dl;1), 8 samples in MSUD(4mg/dl;2, 6mg/dl;2, 8mg/dl;3, 10mg/dl;1), 4 samples in HCU(4mg/dl;2, 6mg/dl;2), 4 samples in Galactosemia(4mg/dl;2, 6mg/dl;1, 8mg/dl;1), respectively. while, no one was positive in HE. The frequncy rate were 1/36,000 for PKU, HCU and GAL, 1/18,000 for MSUD, respectively. But those for HE couldn't be detected in our survey. In this study, the hightest frequency rate was 1/18,000 of MSUD, following were 1/36,000 for PKU, HCU and GAL, respectively. As results our data, it is our opinion that neonatal screening should be performed in terms of national policies for ealy diagnosis and theraphy.
이온주입 공정을 이용한 4H-SiC p-n Diode에 관한 시뮬레이션 연구
이재상,방욱,김상철,김남균,구상모,Lee, Jae-Sang,Bahng, Wook,Kim, Sang-Cheol,Kim, Nam-Kyun,Koo, Sang-Mo 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.2
Silicon carbide (SiC) has attracted significant attention for high frequency, high temperature and high power devices due to its superior properties such as the large band gap, high breakdown electric field, high saturation velocity and high thermal conductivity. We performed Al ion implantation processes on n-type 4H-SiC substrate using a SILVACO ATHENA numerical simulator. The ion implantation model used Monte-Carlo method. We simulated the effect of channeling by Al implantation in both 0 off-axis and 8 off-axis n-type 4H-SiC substrate. We have investigated the effect of varying the implantation energies and the corresponding doses on the distribution of Al in 4H-SiC. The controlled implantation energies were 40, 60, 80, 100 and 120 keV and the implantation doses varied from $2{\times}10^{14}$ to $1{\times}10^{15}\;cm^{-2}$. The Al ion distribution was deeper with increasing implantation energy, whereas the doping level increased with increasing dose. The effect of post-implantation annealing on the electrical properties of Al-implanted p-n junction diode were also investigated.
이온주입에 의한 고분자(Polyphenylene Sulfide)표면 특성 변화와 선에너지전달(Pineal Energy Transfer)과의 관계
이재상,김보영,이재형,Lee, Jae S.,Kim, Bo-Young,Lee, Jae-Hyung 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.5
Ion implantation provides a unique way to modify the mechanical, optical and electrical properties of polymer by depositing the energy of ions in the material on the atomic scale. Implantation of ions into the polymers generally leads to a radiation damage, which, in many cases, modifies the properties of the surface and bulk of the material. These modifications result from the changes of the chemical structure caused in their turn by changing the chemical bonding when the incident ions cut the polymer chains, breaks covalent bonds, promotes cross-linking, and liberates certain volatile species. We studied the relation among the linear energy transfer (LET) and changes of surface microstructure and surface resistivity on PPS material using the high current ion implantation technology The surface resistivity of nitrogen implanted PPS decreased to $10^{7}{\Omega}/cm^{2}$ due to the chain scission, cross linking, ${\pi}$ electron creation and mobility increase. In this case, the surface conductivity depend on the 1-dimensional hopping mechanism.