• 대한방사성의약품학회지
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• 제5권2호
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• pp.79-82
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• 2019

⁶¹Cu is a promising PET radiometal having favorable nuclear decay characteristics with appropriate half-life of 3.3 h. Owing its promising capabilities in radiopharmaceutical chemistry and its chemical similarities with its isotopes ⁶⁴Cu and ⁶⁷Cu, in this work we have tried to optimize the production and separation conditions of ⁶¹Cu. ⁶¹Cu was produced via (p, x) reaction with natural nickel which was electroplated on the high purity silver coated copper backing target holder. The optimization of target electrodeposition, beam energy and current modulation, target dissolution and separation were optimized in this study. Preliminary studies show that ⁶¹Cu was successfully produced and separated which can be further extended for the production of ⁶⁴Cu and ⁶⁷Cu.

• 한국재료학회지
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• 제14권3호
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• pp.203-210
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• 2004

Effects of various pretreatments on the adhesion of copper-coated polymer films were investigated. Copper-coated polymer films were prepared by an electron cyclotron resonance-metal organic chemical vapor deposition (ECR-MOCVD) coupled with a DC bias system at room temperature. PET(polyethylene terephthalate) film was employed as a substrate material and it was pretreated by industrially feasible methods such as chromic acid, sand-blasting, oxygen plasma and ion-implantation treatment. Surface characterization of the copper-coated polymer film was carried out by AFM(Atomic Force Microscopy) and FESEM(Field Emission Scanning Electron Microscopy). Surface energy was calculated by based on the value of the contact angle measured. The adhesion of copper/PET films was determined by a pull-off test according to ASTM D-5179. It was found that suitable pretreatment of the PET substrate was required for obtaining good adhesion property between copper films and the substrate. In this study the highest adhesion was observed in sand-blasting, and then followed by those of acid and oxygen plasma treatment. However, the effect of surface energy was insignificant in our experimental range. This is probably due to compensating the difference in surface energy from various pretreatments by exposing substrate to ECR plasma for 5 min or longer at the early stage of the copper deposition. Therefore, it can be concluded that surface roughness of the polymer substrate plays an important role to determine the adhesion of copper-coated polymer for the deposition of copper by ECR-MOCVD.

• 핵의학기술
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• 제12권3호
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• pp.176-180
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• 2008

Department of Nuclear Medicine in Seoul National University Hospital (SNUH) had developed $^{18}F$-Flumazenil as Benzodiazepine receptor imaging agent for PET diagnosis of Epilepsy. But production Activity of $^{18}F$-Flumazenil is decreased owing to this method has difficult synthesis procedures and pretty long synthesis time. In this study, we can modify synthesizing method to have more simple procedure and less spend time and help to increase production Activity. Old method: Radioactivity was produced by cyclotron was captured by QMA cartridge that was activated. Captured radioactivity was eluted into the reaction vial by using kryptofix solution and delivered. After evaporation of eluent, the azeotrophic drying step repeated two times. tosylflumazenil in anhydrous Acetonitrile was added to a reaction vial while bubbling. The reaction mixture was evaporated until the mixture volume was 0.5 mL. Reaction vial washed with 20 % Acetonitrile and that solution went into the reaction vial. The reaction mixture was loaded to the HPLC loop by hand and purified $^{18}F$-Flumazenil by HPLC column. New method: We used $TBAHCO_3$ solution as a eluent. After the eluent was evaporated, tosylflumazenil in anhydrous acetonitrile was added to a reaction vial and the reaction mixture was bubbled for 15 minutes. It was evaporated until the mixture volume became 0.5 mL. It was loaded to the HPLC loop. In old method, $^{18}F$-Flumazenil was synthesized via 6 steps synthesis procedures in 105 minutes with 30~35% synthesizing yield (non-decay correction) and specific activity was about $0.5{\sim}2{\times}10^5$ Ci/mole. In new method, It had 3 steps synthesis procedures in 53 minutes with 40~45% synthesizing yield and specific activity was about $3{\sim}8{\times}10^5$ Ci/mole. This method leads to improve of minimizing synthesis time, increasing synthesis yield and specific activity. While we can load reaction mixture to the HPLC loop, we can expose high radiation field thanks to used by hand.

• Journal of Radiation Protection and Research
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• 제38권3호
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• pp.157-165
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• 2013

To determine the factors affecting the external radiation dose rates of patients undergoing PET-MRI examinations and to assess the trends of these differences, we measured the changes in the dose rates of $^{18}F$-FDG during a set period of time for each body region. Consistent with theoretical predictions, the dose rate decreased over time in patients undergoing PET-MRI examinations. Furthermore, immediately after the $^{18}F$-FDG injection, the dose rate in the chest region was the highest, followed by the abdominal region, the head region, and the foot region. The dose rate decreased drastically as time passed, by 2.47-fold, from $339.23{\pm}74.70mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection to $102.71{\pm}26.17mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. In the foot region, there were no significant changes over time, from $32.05{\pm}20.23mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection, to $23.89{\pm}9.14mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. The dose rate is dependent on the individual characteristics of the patient, and differed depending on the body region and time point. However, the dose rates were higher in patients who had a lower body weight, shorter stature, fewer urinations, lower fluid intake, and history of diabetes mellitus. To decrease radiation exposure, it is difficult or impossible to change factors inherent to the patient, such as sex, age, height, body weight, obesity, and history of diabetes mellitus. However, factors which can be changed, such as the $^{18}F$-FDG dose, fasting time, fluid intake, number of urinations, and contrast agent dose can be controlled to minimize the external radiation exposure of the patient.

• 대한핵의학회지
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• 제36권1호
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• pp.1-7
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• 2002

Positron Emission Tomography (PET) is a nuclear medicine imaging modality that consists of systemic administration to a subject of a radiopharmaceutical labeled with a positron-emitting radionuclide. Following administration, its distribution in the organ or structure under study can be assessed as a function of time and space by (1) defecting the annihilation radiation resulting from the interaction of the positrons with matter, and (2) reconstructing the distribution of the radioactivity from a series of that used in computed tomography (CT). The nuclides most generally exhibit chemical properties that render them particularly desirable in physiological studies. The radionuclides most widely used in PET are F-18, C-11, O-15 and N-13. Regarding to the number of the current PET Centers worldwide (based on ICP data), more than 300 PET Centers were in operation in 2000. The use of PET technology grew rapidly compared to that in 1992 and 1996, particularly in the USA, which demonstrates a three-fold rise in PET installations. In 2001, 194 PET Centers were operating in the USA. In 1994, two clinical and research-oriented PET Centers at Seoul National University Hospital and Samsung Medical Center, was established as the first dedicated PET and Cyclotron machines in Korea, followed by two more PET facilities at the Korea Cancer Center Hospital, Ajou Medical Center, Yonsei University Medical Center, National Cancer Center and established their PET Center. Catholic Medical School and Pusan National University Hospital have finalized a plan to install PET machine in 2002, which results in total of nine PET Centers in Korea. Considering annual trends of PET application in four major PET centers in Korea in Asan Medical Center recent six years (from 1995 to 2000), a total of 11,564 patients have been studied every year and the number of PET studies has shown steep growth year upon year. We had 1,020 PET patients in 1995. This number increased to 1,196, 1,756, 2,379, 3,015 and 4,414 in 1996,1997,1998,1999 and 2000, respectively. The application in cardiac disorders is minimal, and among various neuropsychiatric diseases, patients with epilepsy or dementia can benefit from PET studios. Recently, we investigated brain mapping and neuroreceptor works. PET is not a key application for evaluation of the cardiac patients in Korea because of the relatively low incidence of cardiac disease and less costly procedures such as SPECT can now be performed. The changes in the application of PET studios indicate that, initially, brain PET occupied almost 60% in 1995, followed by a gradual decrease in brain application. However, overall PET use in the diagnosis and management of patients with cancer was up to 63% in 2000. The current medicare coverage policy in the USA is very important because reimbursement policy is critical for the promotion of PET. In May 1995, the Health Care Financing Administration (HCFA) began covering the PET perfusion study using Rubidium-82, evaluation of a solitary pulmonary nodule and pathologically proven non-small cell lung cancer. As of July 1999, Medicare's coverage policy expanded to include additional indications: evaluation of recurrent colorectal cancer with a rising CEA level, staging of lymphoma and detection of recurrent or metastatic melanoma. In December of 2001, National Coverage decided to expand Medicare reimbursement for broad use in 6 cancers: lung, colorecctal, lymphoma, melanoma, head and neck, and esophageal cancers; for determining revascularization in heart diseases; and for identifying epilepsy patients. In addition, PET coverage is expected to further expand to diseases affecting women, such as breast, ovarian, uterine and vaginal cancers as well as diseases like prostate cancer and Alzheimer's disease.

• 대한방사성의약품학회지
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• 제3권1호
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• pp.3-14
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• 2017

Nucleophilic aromatic fluorination has been one of the most explored methods in fluorin-18 based radiochemistry. Unlike electrophilic $[^{18}F]$fluorination methods, no-carrier-added nucleophilic radiofluorination with cyclotron-produced $[^{18}F]$fluoride ion offers better specific radioactivity which is essential aspect to obtain good quality images from positron emission tomography. Contrary to amenable aliphatic radiofluorination, the development of reliable aromatic $[^{18}F]$fluorination methods has been pursued by many research groups; however, no viable method has yet been established. Recently, hypervalent iodine compound draws increasing attention as versatile radiolabeling precursor for various $[^{18}F]$fluoroarenes, since it bears the capacity to introduce fluorine-18 either on electron-deficient or electron-rich aryl ring with enhanced regiospecificity. Other classes of hypervalent iodine congeners often utilized in radiochemistry are iodylarenes, iodonium ylides, and spirocyclic iodonium ylides. Recently developed spirocyclic iodonium ylides have already been avidly employed to provide various $[^{18}F]$aryl fluorides with high labeling efficiency. This metal-free protocol would afford efficient routes, replacing the traditional approaches to $[^{18}F]$fluoroarenes, from prosthetic labeling synthons to complex PET radiotracers.

• 대한방사성의약품학회지
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• 제7권1호
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• pp.22-32
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• 2021

Fluorine-18 is by far the most widely exploited radionuclide in PET (positron emission tomography) radiochemistry. The physical half-life of fluorine-18 allows for chemical manipulation within a restricted timeframe, and cyclotron-produced fluoride ion has been widely applied in aliphatic and aromatic nucleophilic radiofluorinations to produce a variety of established radiotracers. Radiotracers have become more structurally complicated to address diverse targets in physiobiological systems. There is therefore an unmet need to complement traditional C-¹⁸F bond-forming radiofluorination with new and efficient radiolabeling techniques to tackle the myriad of possible chemical environments. This review discusses recent advances in organometallic fluorine-18 bond creation in ¹⁸F-radiochemistry. Although not widely employed, new radiolabeling strategies for constructing boron-¹⁸F, silicon-¹⁸F, aluminum-¹⁸F, and other metal-¹⁸F bonds are described in view of their potential use in the development of novel radiopharmaceuticals.

• 핵의학기술
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• 제16권1호
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• pp.50-56
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• 2012

일시 출입자로 분류된 핵의학과 출입 환경미화원은 주기적으로 타과와 업무순환을 하고, 또한 작업 시간과 환경 등의 변화가 많기 때문에 관리하기에 어려운 점이 있으며 따라서 이들의 분류를 명확히 할 필요가 있다. 이에 본 논문에서는 핵의학과에서 근무하는 환경미화원의 피폭 상황을 분석하여 일시 출입자로 분류된 조건의 타당성에 대하여 검토해 보고 작업 환경의 변화 및 근무 시간의 조절이 필요한가를 알아보았다. 우선 먼저 PET실과 혈액 검사실에서 근무하는 환경미화원과 감마 카메라실에서 근무하는 환경 미화원 2명을 대상으로 한 달간 근무 시간 중에 OSL을 각각 착용시켜 개인 피폭 선량을 측정하였다. 둘째로 survey meter를 이용하여 두 명의 환경미화원의 작업 환경, 근무 형태에 따라 시간대 별로 핵의학과 내 14개 구역을 선정, 총 10회 공간 선량률을 측정한 결과 이들의 피폭 선량은 연간 1mSv를 초과하지 않았으며, survey meter를 이용하여 조사한 결과 또한 연간 1 mSv를 초과하지 않을 것으로 추정되지만 그 수치가 1 mSv에 근접하였다. 따라서 일시 출입자로써의 분류를 좀 더 명확히 하기 위해서는 PET 안정실과 같은 피폭이 상대적으로 많은 구역에서의 노출 확률을 줄이기 위하여 이들에게 방사선 관리 구역내 교육을 실시하고, 또한 근무시간 및 근무 형태를 적절히 변경한다면 이들의 피폭 선량은 확연히 줄어들 것으로 사료된다.

• 전기화학회지
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• 제8권3호
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• pp.139-145
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• 2005

전자싸이크로트론공명(ECR: Electro Cyclotron Resonance)상온화학증착법에 의해 PET 폴리머기판위에 $SnO_x$ 박막을 제조하고, Sn의 전구체인 TMT(Tetra-methyl Tin)에 대한 산소와 수소의 몰 비 변화가 박막의 특성에 미치는 영향을 조사하였다 비화학양론적인 결합에 의해 성장된 투명 주석 산화막은 주입되는 산소/TMT, 수소/TMT몰 비에 의하여 조성비가 결정되고, 결정된 조성비에 의해 전기적 성질이 결정되는 것을 확인할 수 있었다. 산소/TMT의 몰 비 변화에 대하여 PET(polyethylene terephthalate)에 증착된 $SnO_x$ 박막의 최적 조성비는 1:2.4이다. 조성비는 반응에 참가하는 산소의 양이 증가할수록 점차적으로 증가하고, 과량의 몰 비로 산소가 주입될 경우 박막내의 Sn과 결합하지 않고 잉여 산소전하밀도를 증가시켜 bulk한 박막을 형성해 전기 비저항을 증가시키는 주요 원인이 된다. 수소/TMT의 몰 비는 산소 몰 비와 같이 증착되는 $SnO_x$의 몰 비에 영향을 주어 조성비를 변화시킴으로서 전기비저항을 결정하는데 크게 기여한다. 반응기내에 공급되는 수소량이 적으면 TMT의 불완전한 분해를 초래하여 반응에 필요한 $Sn^+$ 이온농도가 낮아지게 되고,상대적으로 잉여 산소함량이 증가하면서 높은 저항을 나타낸다. 임계값 이상으로 많은 양의 수소를 공급하면 플라즈마 내에 존재하는 $O^-$ 이온을 환원시켜 주석 산화막의 형성에 필요한 $O^-$ 이온의 감소로 전기저항이 오히려 증가하게 된다. 따라서 박막의 Sn:O의 조성비는 주입되는 산소량이 증가할수록 더욱 큰 값을 갖게 되고, 주입되는 수소량이 증가할수록 작은 값을 갖게 된다. 본 연구범위에서 TMP에 대한 산소의 몰 비는 80배, 수소의 몰 비는 40배일 때 가장 투명도와 전기전도도를 지니는 박막 특성을 나타내었다.

• 대한방사성의약품학회지
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• 제3권2호
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• pp.113-115
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• 2017

Since the nitrile group is commonly found in natural products and bioactive molecules, many scientists' interest has been focused on the usage of nitrile group. Novel reactions for $^{11}C-labelling$ using nitrile group have been developed, and novel preparation protocols of biomolecules labeled with $^{11}C$ have been studied. In this highlight review, recent researches for the novel labeling reactions using nitrile group are illustrated.