• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.6
• /
• pp.2958-2965
• /
• 2013

Purpose : To evaluate the degree of malignancy of incident thyroid lesion found in 18F-FDG PET/CT findings and the usefulness of the method suggested in this study, we applicate the Delay Scan Method that differentiate a false positive benign tumor, inflammation and malignancy, as well as make the criteria of SUV. Materials and Methods : A retrograde study was conducted of 25 patients(1 exception) who were admitted in E hospital to receive 18F-FDG PET/CT examination until Janaary and April of 2008. 18F-FDG PET/CT image photographing was taken in Biograph-Duo made by SIEMENS, after taking normal 18F-FDG PET/CT image(1hr) and then 1hr later we took the thyroid 1 bed-delayed image for the patients who showed abnormal thyroid 18F-FDG uptake and above 2.0 SUV for 2 minutes every 1 bed. For the patients who showed abnormal thyroid uptake and above 2.0 SUV, 1hr later, we took a 1 bed-delayed image and then made a comparative study between measured maxSUV of 1hr-abnormal uptake image and that of 2hr-delayed image. Results : In this 18F-FDG PET/CT study among the patients who showed incidental 18F-FDG thyroidal uptake the number of thyroid cancer was 5(20.8%), all of then showed benign findings. a comparison of results for 18F-FDG PET/CT. the benign patient measured maxSUV in the PET/CT. image(1hr) mean value 5.06maxSUV and delay image(2hr) mean value 5.23maxSUV differences of two value is 0.19maxSUV and the malignantIt patient measured maxSUV in the PET/CT. image(1hr) mean value 9.63maxSUV and delay image(2hr) mean value 10.65maxSUV differences of two value is 10.65maxSUV in Thyroid abnormal uptake patients. Conclusion : in the case of incidental 18F-FDG uptake in thyroid, max SUV of focal thyroid lesion is above 5.0 if 18F-FDG PET/CT examine the delayed images to add, You could see that reasonable diagnostic method useful. to differentiate whether lesions of malignant.

• The Korean Journal of Nuclear Medicine
• /
• v.36 no.4
• /
• pp.261-270
• /
• 2002

Purpose: Nicotinic acetylcholine receptors (nAChRs), which mediate excitatory neurotransmission, are known to participate in various neurophysiological functions. Severe losses of nAChRs have been noted in Alzheimer's and Parkinson's diseases. Therefore, noninvasive and quantitative imaging of nAChRs would offer a better understanding on the function of these receptors. In this study, $2-[^{18}F]fluoro-A85380\;([^{18}F]1)$, an ${\alpha}_4{\beta}_2$ nAChRs radioligand, was prepared using one HPLC purification and evaluated in mouse brain, and the results were compared with those in the literature. Materials and Methods: $[^{18}F]1$ was prepared by $[^{18}F]$fluorination of the iodo precursor followed by acidic deprotection and then purified by HPLC. Tissue distribution studies were performed in mouse brain at the indicated time points and the result was expressed as %ID/g. Inhibition studies were also carried out with pretreatment of various ligands. Results: One HPLC purification method gave the desired product in 15-20% radiochemical yield and with high specific activity ($38-55GBq/{\mu}mol$). Tissue distribution studies showed that $[^{18}F]1$ specifically labeled nAChRs in mouse brain with a high thalamus to cerebellum uptake ratio (13.8 at 90 min). Inhibition studios demonstrated selective binding of $[^{18}F]1$ to nAChRs, blocking the uptake of the $[^{18}F]1$ in nAChR-rich legions by selective ligands such as cytisine and nicotine which are well-known nAChRs agonists. Conclusion: This study demonstrated that the $[^{18}F]1$ produced by the method using one HPLC purification gave the results similar to those reported in the literature. Therefore, this synthetic method can be readily applied to the routine preparation of $[^{18}F]1$, a PET radioligand for ${\alpha}_4{\beta}_2$ nAChRs imaging.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.sup1
• /
• pp.140-148
• /
• 2008

$^{18}F-FDG$ PET showed a high sensitivity and specificity in the initial staging of malignant melanoma, and it also predicted the prognosis correctly. In addition, it had a higher sensitivity and specificity in the detection of recurrence and restaging than conventional imaging modalities. Meanwhile, there's less clinical evidence to support the use of $^{18}F-FDG$ PET in the response evaluation for chemotherapy and the diagnosis/differential diagnosis of malignant melanoma.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.sup1
• /
• pp.14-16
• /
• 2008

Salivary gland tumors are relatively rare, constituting 3% of all head and neck neoplasms. In patients with salivary gland malignancies, $^{18}F-FDG$ PET is clinically useful in initial staging, histologic grading, and monitoring after treatment. According to clinical research data hitherto, $^{18}F-FDG$ PET is expected to be an effective diagnostic tool in the management of salivary gland tumors.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.sup1
• /
• pp.149-152
• /
• 2008

Nonmelanomatous skin cancer includes basal cell carcinoma, squamous cell carcinoma, merkel cell carcinoma and dermatofibrosarcoma protuberance. So far, there have been a few reports that $^{18}F-FDG$ PET was useful in the evaluation of metastasis and therapeutic response in nonmelanomatous skin cancer, however, those are very weak evidences. Therefore, further studies on the usefulness of $^{18}F-FDG$ PET in nonmelanomatous skin cancer are required.

• Journal of the Korean Society of Systems Engineering
• /
• v.5 no.1
• /
• pp.7-20
• /
• 2009

This paper describes a case study on the R&D programs of fighter and attacker aircraft such as F-22A, F/A-18E/F, and T/A-50. F-22A and F/A-18E/F were developed in same age. The performance of each program was, however extremely different. F-22A program results in a lot of cost overrun and schedule delay. On the other hand F/A-18E/F program met the cost, schedule, and performance goals. In the T/A-50 program with a super-sonic advanced trainer, T-50 was also developed successfully on planned cost and time by Korea Air-force and KAI. This paper derives key elements for the success of the military aircraft R&D program through lessons learned from th e case study. Each program is analyzed in terms of its background, planning and management.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.3 no.1
• /
• pp.3-14
• /
• 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.

• The Korean Journal of Nuclear Medicine
• /
• v.35 no.3
• /
• pp.185-191
• /
• 2001

Objectives: Recently, $[methyl-^{11}C]-({\beta}$-Hydroxyethyl)trimethylammonium ($[^{11}C]$choline) Has been discovered to be a very effective tracer in imaging various human tumors using positron omission tomography. Because of the short half-life of C-11, it is very difficult to use in a routine imaging procedure and needs a frequent synthesis of $[^{11}C]$choline. This can be supplemented by the substitution of $[^{11}C]$choline with $[methyl-^{18}F]$fluorocholine. Here, we would like to report ceil uptake and biodistribution of $[^{11}C]$choline and $[^{18}F]$fluorocholine as a basic study. Methods: $[^{11}C]$Choline was prepared by the treatment of $[^{11}C]CH_3I$ with N,N-dimethylaminoethanol and $[^{18}F]$fluorocholine was synthesized from reaction of $CH_2Br[^{18}F]F$ with N,N-dimethylaminoethanol. The radiochemical purity was checked by high performance liquid chromatography (HPLC). The blodistribution of $[^{11}C]$choline and $[^{18}F]$fluorocholine was determined in balb/c mouse at 5 min, 20 min, 40 min and 80 min. The cell uptake was measured using glioma (9L) and colon adenocarcinoma (SW620). Results: The radiochemical purity was more than 98% after purification. In the liver, uptake did not change over time; the uptake was 20%ID/g for $[^{11}C]$choline and 13%ID/g for $[^{18}F]$fluorocholine. In the kidney, radioactivity decreased over time; the uptake was 15%ID/g for $[^{11}C]$choline and 20%ID/g for $[^{18}F]$fluorocholine, 80 min post-injection. The cell uptake of $[^{11}C]$choline was 4.93% for glioma (9L) and 18.69% for colon adenocarcinoma (SW620). For $[^{18}F]$fluorocholine, 1.77% for glioma (9L) and 2.77% for colon adenocarcinoma (SW620). Conclusion: $[^{11}C]$Choline and $[^{18}F]$fluorocholine showed a different cell uptake tendency, depending on cancer cell line.

• The Korean Journal of Nuclear Medicine
• /
• v.34 no.4
• /
• pp.294-302
• /
• 2000

Purpose: To investigate the mechanisms related to F-18-FDG uptake by tumors, F-18-FDG accumulation was compared with glucose transporter-1 (Glut-1) expression and hexokinase activity in various human cancer cell lines. Materials and Methods: Human colon cancer (SNU-C2A, SNU-C4, SNU-C5), hepatocellular carcinoma (SNU-387, SNU-423, SNU-449), lung cancer (NCI-H522, NCI-H358, NCI-H1299), uterine cervical cancer (HeLa, HeLa 229, HeLa S3) and brain tumor (A172, Hs 683) cell lines were used. After 24 hr incubation of $5{\times}10^5$ cells, 37 kBq F-18-FDG was added and the uptake by cells at 10 min was measured using a gamma counter. Hexokinase activity was measured by continuous spectrophotometric rate determination. To measure mitochondrial hexokinase activity, mitochondrial fraction was separated by a high speed centrifuge. Immunohistochemical staining of Glut-1 was performed, and graded as 0, 1, 2, or 3 according to expression. Results: There was difference among F-18-FDG uptake, total and mitochondrial hexokinase activity, and Glut-1 expression with different cancer cell lines. The correlations of F-18-FDG with total hexokinase and mitochondrial hexokinase activity were low (r=0.27 and 0.26, respectively). Glut-1 expression showed a good correlation with F-18-FDG uptake (p=0.81, p=0.0015). Previously, we reported no correlation of F-18-FDG uptake with hexokinase activity in colon cancer cell lines. Thus, when colon cancer cells were excluded, F-18-FDG uptake showed higher correlation with total hexokinase and mitochondrial hexokinase activity (r=0.81, p=0.0027 and r=0.81, p=0.0049, respectively). Conclusion: Both Glut-1 expression and hexokinase activity were contributing factors related to F-18-FDG accumulation in human cancer cell lines. The relative contribution of Glut-1 expression and hexokinase activity, however, was different among different cancer cell types.

• The Journal of the Korea Contents Association
• /
• v.9 no.11
• /
• pp.262-270
• /
• 2009

$^{18}F$-mefway has been developed as radioligand for serotonin receptor 5-$HT_{1A}$. The object of this study was to obtain the mefway precursor with the higher yield than previous method and to identify whether $^{18}F$-mefway can bind to 5-$HT_{1A}$ or not. from microPET imaging of small animal brain. Precursor was prepared by a modification of the reported procedure then [$^{18}F$] labeling was performed by adding $^{18}F$ ion at $130^{\circ}C$ in the hot cell for 30min. After purification of reaction mixture using alumina Sep-pak and HPLC, microPET images of small animal brain were determined. The chemical yield of precursor was increased from 9% to 34% using oxalyl chloride and LAH/diethylether. We synthesized a precursor which was successfully labeled with no-carrier-added $^{18}F$-by new synthetic route. This research suggest that $^{18}F$-mefway will be used a radiopharmaceutical for evaluation of central nerve system disorder as imaging a gent for 5-$HT_{1A}$ receptor.