• Journal of Gastric Cancer
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• v.18 no.3
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• pp.218-229
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• 2018

Purpose: This study investigated whether the metabolic avidity of primary tumors and/or metastatic lymph nodes (LNs) measured by $^{18}F$-fluorodeoxyglucose ($^{18}F-FDG$) positron emission tomography/computed tomography (PET/CT) was related to survival after surgery in patients with advanced gastric cancer (AGC). Materials and Methods: One hundred sixty-eight patients with AGC who underwent preoperative $^{18}F-FDG$ PET/CT and curative resection were included. The $^{18}F-FDG$ avidity of the primary gastric tumor and LNs was determined quantitatively and qualitatively. The diagnostic performance of $^{18}F-FDG$ PET/CT was calculated, and the prognostic significance of $^{18}F-FDG$ avidity for recurrence-free survival (RFS) and overall survival (OS) was assessed. Results: In all, 51 (30.4%) patients experienced recurrence, and 32 (19.0%) died during follow-up (median follow-up duration, 35 months; range, 3-81 months); 119 (70.8%) and 33 (19.6%) patients showed $^{18}F-FDG$-avid primary tumors and LNs, respectively. $^{18}F-FDG$ PET/CT showed high sensitivity (73.8%) for the detection of advanced pathologic T ($pT{\geq}3$) stage and high specificity (92.2%) for the detection of advanced pN (${\geq}2$) stage. $^{18}F-FDG$ avidity of LNs was significantly associated with RFS (P=0.012), whereas that of primary tumors did not show significance (P=0.532). Univariate and multivariate analyses revealed that $^{18}F-FDG$ avidity of LNs was an independent prognostic factor for RFS (hazard ratio=2.068; P=0.029). Conclusions: $^{18}F-FDG$ avidity of LNs is an independent prognostic factor for predicting RFS. Preoperative $^{18}F-FDG$ PET/CT can be used to determine the risk and prognosis of patients with AGC after curative resection.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.151-156
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• 2012

$^{18}F$-fluorodeoxyglucose ($^{18}F$-FDG) causes a significant amount of radioactivity retention in kidneys and urinary tract and degrades image quality and diagnostic performance. Diuretics are used to perform tests and prevent the urinary tract retention of $^{18}F$-FDG. The purpose of the study is to investigate how the diuretics affect images and excretion rates of $^{18}F$-FDG. The study consists of a group using diuretics for patients with no primary tumors or transfer lesions in kidneys according to PET/CT images, a group using physiological saline and the control group injecting only $^{18}F$-FDG and SUVs are measured by configuring interested areas for each group. Also, SUVs are compared and evaluated depending on the lasix injection after basic inspection and injecting $^{18}F$-FDG for quantitative analysis. The study shows that images with decreased background radioactivity and increased urine excretion due to using diuretics. However, an opposite result that there is no change in the amount of radioactivity in urine appears. The study concludes that the diuretics may decrease background radioactivity in the images but may not affect the $^{18}F$-FDG excretion.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.73-83
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• 2016

Imaging hypoxia using positron emission tomography (PET) is of great importance for cancer therapy. [$^{18}F$] Fluoromisonidazole (FMISO) was the first PET agent used for imaging tumor hypoxia. Various radiolabeled nitroimidazole derivatives such as [$^{18}F$]fluoroerythronitroimidazole (FETNIM), [$^{18}F$]1-${\alpha}$-D-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole(FAZA), 2-(2-nitroimidazol-1-yl)-N-(3,3,3-[18F]-trifluoropropyl)acetamide ([$^{18}F$]EF-3), [$^{18}F$]2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide (EF-5), 3-[$^{18}F$]fluoro-2-(4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3,-triazol-1-yl)-propan-1-ol ([$^{18}F$]HX-4), and [$^{18}F$]fluoroetanidazole (FETA) were developed successively. However, these imaging agents still produce PET images with limited resolution; the lower blood flow in hypoxic tumors compared to normoxic tumors results in low uptake of the agents in hypoxic tumors. Thus, the development of better imaging agents is necessary.

• Journal of Radiation Industry
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• v.11 no.1
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• pp.13-18
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• 2017

Recently, the number of PET cyclotrons has increased in Korea. A cyclotron mainly produces $^{18}F$, which is used for the production of [$^{18}F$]FDG, a cancer diagnostic radiopharmaceutical. For radiation protection, the discharge control standard under the Nuclear Safety Act limits the radioactive concentration of $^{18}F$ in the exhaust discharged from a nuclear power utilization facility to below $2,000Bq\;m^{-3}$. However, the radioactive concentration of $^{18}F$ discharged during [$^{18}F$]FDG production at the cyclotron facility at Chosun University is maintained at about $1,500Bq\;m^{-3}$ on average, which is 75% of the concentration limit of the discharge control standard, and temporarily exceeds the standard as per the real-time monitoring results. This study evaluated the performance of the exhaust filter unit of the cyclotron facility at Chosun University by assessing the concentration of $^{18}F$ in the exhaust, and an experiment was conducted on the discharge reduction, where $^{18}F$ is discharged without reacting with the FDG precursors during [$^{18}F$]FDG synthesis and is immediately captured by the [$^{18}F$]FDG automatic synthesis unit. Based on the performance evaluation results of the exhaust filter at the cyclotron facility of Chosun University, the measured capture efficiency before and after the filter was found to be 92%. Furthermore, the results of the discharge reduction experiment, where the exhaust $^{18}F$ was immediately captured by the [$^{18}F$]FDG synthesizer, showed a very satisfactory 94.3% reduction in the concentration of discharge compared to the existing discharge concentration.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.532-540
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• 1996

목적 : 종양세포의 증식을 평가하기 위해 radiofluorinated ethyluracil (FEU)과 deoxyadenosine analogue(FAD)를 합성하여 종양의 영상화를 시도하였다. 대상 및 방법 : 5-(2-Fluoroethyl)uracil ([$^{18}F$]FEU)은 2, 4-dimethoxy-5-(2-hydroxyethyl) pyrimidine을 $K^{18}F$와 처리한 후 HBr로 가수분해하여 얻었으며 Fluorodeoxyadenosine은 adenosine의 triacetylated analogue를 $K^{18}F$와 처리하여 얻었다. 생물학적 조직분포는 유방암 세포(13762 NF, 100,000 cells per rat, im)를 쥐에 접종한 후 0.5, 1, 2 및 4시간에 주요장기를 적출하여 %ID/g을 측정하고 자가방사영상은 방사성의약품 투여 45분 후에 얻었다. PET 영상은 VX-2 종양을 접종한 가토를 이용하여 얻었다. In vitro cell proliferation assay는 사람의 말초단핵구를 이용하였다. 결 과 : In vitro assay상 ([$^{18}F$]FEU는 세포증식시 DNA/RNA에 결합함을 시사하였다. ([$^{18}F$]FAD와 ([$^{18}F$]FEU의 종양/비종양 방사능 섭취비는 시간경과에 따라 증가하였으며 ([$^{18}F$]FAD와 ([$^{18}F$]FEU를 이용한 자가방사영상과 ([$^{18}F$]FEU를 이용한 PET 영상에서 종양을 잘 관찰할 수 있었다. 결 론 : ([$^{18}F$]FAD 및 ([$^{18}F$]FEU를 이용하여 종양세포의 증식을 PET 영상에서 평가할 수 있으리라 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1268-1275
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• 2010

Post-weaning diarrhoea (PWD) and oedema disease (ED) caused by E. coli F18 always result in economic losses to pig producers, and no effective methods of controlling PWD and ED are presently available. FUT1 has been identified as a candidate gene controlling the expression of E. coli F18 receptor. This study examined the correlation between F18ab and F18ac adhesion phenotypes and the polymorphism at position M307 of the FUT1 gene in three pig breeds (231 Large White, 107 Landrace and 109 Songliao Black). The results showed: i) Both the susceptible genotypes (GG and GA) and the adhesion phenotypes (adhesive or weekly adhesive) were dominant in all three breeds with frequencies over 95%. ii) Three adhesion patterns of the two F18 variants F18ab and F18ac, i.e., ($ab^+$, $ac^+$), ($ab^+$, $ac^-$) and ($ab^-$, $ac^-$), were found in all three breeds, and there was no significant difference in the distribution of adhesion phenotypes of the two variants (separately or jointly) among the three breeds (p>0.05). iii) The FUT1 M307 genotypes were completely associated with the F18ab adhesion phenotypes and very strongly associated with the F18ac adhesion phenotypes. All individuals of genotype AA were non-adhesive to both F18ab and F18ac. All individuals of genotype GG or GA were adhesive to F18ab, whereas 11% of them were non-adhesive to F18ac. These results suggest that the polymorphism at FUT1 M307 can be used for marker-assisted selection of PWD and ED resistant pigs.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3309-3312
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• 2010

D-[$^{18}F$]FMAU and L-[$^{18}F$]FMAU are F-18 labeled nucleoside analogue which have been efficiently synthesized in order to be a PET imaging probe. D-[$^{18}F$]FMAU and L-[$^{18}F$]FMAU were compared as PET imaging agents using HSV1-TK gene expressing tumor-bearing mice. Their cellular uptake profiles were also compared using MCA and MCA-TK cell lines. D-[$^{18}F$]FMAU demonstrated higher cellular uptake and higher accumulation in MCA-TK tumor regions than L-[$^{18}F$]FMAU. On the other hand, L-[$^{18}F$]FMAU showed higher MCA-TK/MCA ratio of %ID/g than that of D-[$^{18}F$]FMAU. L-[$^{18}F$]FMAU can be utilized as a good candidate for HSV1-TK PET imaging. It can be used for antiviral drug evaluation.

• The Korean Journal of Nuclear Medicine
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• v.33 no.6
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• pp.502-511
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• 1999

Purpose: F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been proven to be useful in the differential diagnosis of breast mass and staging of breast cancer. This study assessed the diagnostic accuracy of F-18-FDG PET in the differentiation of breast mass and staging of breast cancer. Materials and Methods: Total 42 patients who had breast mass underwent F-18-FDG PET (all female, 40: 10 year old). We compared F-18 FDG PET results with pathologic findings in 24 patients Results: In the differentiation of breast mass, sensitivity and specificity were 95% (19/20) and 77% (7/9) respectively. Three false positive cases were due to inflammation and one false negative patient had small tumor less than 1 cm. In the assessment of axillary lymph node status, sensitivity and specificity were 73% (8/11) and 100% (7/7) respectively. We found distant metastasis that were not suspected before F-18-FDG PET in 2 patients. Conclusion: F-18-FDG PET shows good diagnostic performance in differentiation of breast mass and staging of breast cancer.

• The Korean Journal of Nuclear Medicine Technology
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• v.28 no.1
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• pp.41-47
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• 2024

Purpose: ¹⁸F-FET, a radiopharmaceutical based on a Tyrosine amino acid derivative using the Sodium-Potassium Pump-independent Transporter (System L) for non-invasive evaluation of primary, recurrent, and metastatic brain tumors, exhibits distinct characteristics. Unlike the widely absorbed ¹⁸F-FDG in both tumor and normal brain tissues, ¹⁸F-FET demonstrates specific uptake only in tumor tissue while almost negligible uptake in normal brain tissue. This study aims to compare and evaluate the usefulness of ¹⁸F-FDG and ¹⁸F-FET Brain PET/CT quantitative analysis in brain tumor diagnosis. Materials and Methods: In 46 patients diagnosed with brain gliomas (High Grade: 34, Low Grade: 12), Brain PET/CT scans were performed at 40 minutes after ¹⁸F-FDG injection and at 20 minutes (early) and 80 minutes (delay) after ¹⁸F-FET injection. SUV_max and SUV_peak of tumor areas corresponding to MRI images were measured in each scan, and the SUV_max-to-SUV_peak ratio, an indicator of tumor prognosis, was calculated. Differences in SUV_max, SUV_peak, and SUV_max-to-SUV_peak ratio between ¹⁸F-FDG and ¹⁸F-FET early/delay scans were statistically verified using SPSS (ver.28) package program. Results: SUV_max values were 3.72±1.36 for ¹⁸F-FDG, 4.59±1.55 for ¹⁸F-FET early, and 4.12±1.36 for ¹⁸F-FET delay scans. The highest SUV_max was observed in ¹⁸F-FET early scans, particularly in HG tumors (4.85±1.44), showing a slightly more significant difference (P<0.0001). SUV_peak values were 3.33±1.13 for ¹⁸F-FDG, 3.04±1.11 for ¹⁸F-FET early, and 2.80±0.96 for ¹⁸F-FET delay scans. The highest SUV_peak was in ¹⁸F-FDG scans, while the lowest was in ¹⁸F-FET delay scans, with a more significant difference in HG tumors (P<0.001). SUV_max-to-SUV_peak ratio values were 1.11±0.09 for ¹⁸F-FDG, 1.54±0.22 for ¹⁸F-FET early, and 1.48±0.17 for ¹⁸F-FET delay scans. This ratio was higher in ¹⁸F-FET scans for both HG and LG tumors (P<0.0001), but there was no statistically significant difference between ¹⁸F-FET early and delay scans. Conclusion: This study confirms the usefulness of early and delay scans in ¹⁸F-FET Brain PET/CT examinations, particularly demonstrating the changes in objective quantitative metrics such as SUV_max, SUV_peak, and introducing the SUV_max-to-SUV_peak ratio as a new evaluation metric based on the degree of tumor malignancy. This is expected to further contributions to the quantitative analysis of Brain PET/CT images.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.233-236
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• 2006

A 67-year-old man with a history of chronic obstructive pulmonary disease (COPD) underwent F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for staging of gastric cancer. The projection images of F-18 FDG PET/CT showed intensely increased F-18 FDG uptake in the anterior neck, chest wall, and upper abdomen. We suspected distant metastases of cervical lymph nodes, ribs, and peritoneum in gastric canter. However, the transaxial images of F-18 FDG PET/CT showed abnormal F-18 FDG uptake in scalene muscles of anterior neck, intercostal muscles of chest wall, and diaphragm of upper abdomen. Patients with COPD use respiratory muscles extensively on the resting condition. These excessive physiologic use of respiratory muscles causes increased F-18 FDG uptake as a result of increased glucose metabolism. The F-18 FDG uptake in respiratory muscles of gastric cancer patient with COPD mimicked distant metastases in cervical lymph nodes, ribs, and peritoneum.