• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.65-69
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• 2011

Purpose: Normal pancreas has low uptake rate in $^{18}F$-FDG PET scan. However, it is possible to diagnose malignancy of pancreatic cancer which has high uptake rate. Many studies approve a high prevalence of diabetes in pancreatic cancer and if the blood glucose level (BGL) is over the normal range, FDG uptake will be decreased and there will be inconvenience for patients from the delay time to reduce the high BGL or could cause difficulty to arrange the schedule. Therefore, we studied the relation of BGL and image quality in pancreatic cancer on PET. Materials and Methods: A hundred patients had PET scan. The prevalence of pancreatic cancer and diabetes were evaluated using SPSS ver. 17. The fasting BGL of patients were examined and sorted as diabetes mellitus (DM) group and Non-DM group. For the evaluation, patients were divided into 3 groups (Non-DM, DM; BGL${\geq}7.0mmol/L$, and DM; BGL<7.0 mmol/L). The ROI was drown on Liver and Lung for the PET imaging analysis. Results: Fifty three male and forty seven female were in the patients. The average age was $60.1{\pm}13.5$. There were 36 patients (male: 22, female: 14, 36%) who had pancreatic cancer with DM. There were 15 patients who showed over 7.0 mmol/L in their fasting BGL and 85 patients who showed under 7.0 mmol/L in their fasting BGL. Among the Non-DM, DM; BGL${\geq}7.0mmol/L$, and DM; BGL<7.0 mmol/L, there was not a statistical significance (p>0.05). Conclusion: The prevalence of pancreatic cancer was comparatively high in this study. If the fasting BGL was slightly over the normal BGL, we believe it will not give a severe disturbance when the patients have PET scan. Furthermore, the examination schedule doesn't need to change and the inconvenience from the delay of patients preparation will be reduced.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.317-322
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• 2009

Purpose: $^{18}$F-flurodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumor aggressiveness and prognosis in various types of cancer. However, pattern of FDG uptake in biliary malignancies and its clinical significance have not been studied well. The purpose of this study was to assess the additional value of $^{18}$F-FDG PET in differential diagnosis and prognosis of cholangiocarcinoma (CC) according to the tumor location and tumor morphology. Materials and Methods: From April 2005 to May 2008, eighty two patients (M:F = 55:27, age 66.2$\pm$9.6 yrs) with CC underwent $^{18}$F-FDG PET. For semiquantitative analysis, the maximum standardized uptake value (SUV$_{max}$) was obtained from the primary tumor. The difference of SUV$_{max}$ according to the tumor location and tumor growth pattern, such as scirrhous type, nodular type, polypoid type were compared. Results: Overall sensitivity of PET scan was 81.7% in CC. SUV$_{max}$ on PET scan in intrahepatic CC was significantly higher compared to extrahepatic CC. In extrahepatic CC, polypoid type showed significantly higher SUV$_{max}$ compared to scirrhous type. Conclusion: $^{18}$F-FDG PET may have a significant impact on clinical decision-making and on the management of intrahepatic cholangiocarcinoma. And it is related to the shape of the tumor and the sensitivity of detection is higher in the mass-forming type than in the scirrhous type.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.1
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• pp.17-29
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• 2015

Purpose For nuclear medicine technologists, it is difficult to stay away from or to separate from radiation sources comparing with workers who are using radiation generating devices. Nuclear medicine technologists work is recognized as an optimized way when they are familiar with work practices. The aims of this study are to measure radiation exposure of technologists working in PET and to evaluate the occupational radiation dose after implementation of strategies to lower exposure. Materials and Methods We divided into four working types by QC for PET, injection, scan and etc. in PET scan procedure. In QC of PET, we compared the radiation exposure controlling next to $^{68}Ge$ cylinder phantom directly to controlling the table in console room remotely. In injection, we compared the radiation exposure guiding patient in waiting room before injection to after injection. In scan procedure of PET, we compared the radiation exposure moving the table using the control button located next to the patient to moving the table using the control button located in the far distance. PERSONAL ELECTRONIC DOSEMETER (PED), Tracerco$^{TM}$ was used for measuring exposed radiation doses. Results The average doses of exposed radiation were $0.27{\pm}0.04{\mu}Sv$ when controlling the table directly and $0.13{\pm}0.14{\mu}Sv$ when controlling the table remotely while performing QC. The average doses of exposed radiation were $0.97{\pm}0.36{\mu}Sv$ when guiding patient after injection and $0.62{\pm}0.17{\mu}Sv$ when guiding patient before injection. The average doses of exposed radiation were $1.33{\pm}0.54{\mu}Sv$ when using the control button located next to the patient and $0.94{\pm}0.50{\mu}Sv$ when using the control button located in far distance while acquiring image. As a result, there were statistically significant differences(P<0.05). Conclusion: From this study, we found that how much radiation doses technologists are exposed on average at each step of PET procedure while working in PET center and how we can reduce the occupational radiation dose after implementation of strategies to lower exposure. And if we make effort to seek any other methods to reduce technologist occupational radiation, we can minimize and optimize exposed radiation doses in department of nuclear medicine. Conclusion From this study, we found that how much radiation doses technologists are exposed on average at each step of PET procedure while working in PET center and how we can reduce the occupational radiation dose after implementation of strategies to lower exposure. And if we make effort to seek any other methods to reduce technologist occupational radiation, we can minimize and optimize exposed radiation doses in department of nuclear medicine.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.53-59
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• 2011

Purpose: To evaluate the dosimetry and image of very low does CT attenuation correction for phantom using pediatric PET/CT. Materials and methods: three PET / CT scanners (Discovery STe, BiographTruepoint 40, Discovery 600) as a child-size acrylic phantom and ion chamber dosimeter (Unfous Xi CT, Sweden) using a CT image acquisition parameters (10, 20, 40, 80, 100, 160 mA; 80, 100, 120, 140 kVp) by varying the depth dose and evaluate $CTDI_{vol}$ value. And each attenuation corrected PET/CT images used NEMA PET Phantom$^{TM}$ (NU2-1994) was evaluated by SUV. Results: Abdominal diagnosis CT dose in general pediatric (about 10 ages) parameter (100 kVp, 100 mA) than very low dose CT parameter (80 kVp, 10 mA) at the depth dose was reduced approximately 92%, $CTDI_{vol}$ was reduced to about 88%. Each CT attenuation corrected parameters PET images showed no change in the value of SUV. Conclusion: for pediatric patients, PET/CT scan can be obtained with very low dose attenuation correction CT (80 kVp, 10 mA), and such attenuation correction CT dose was reduced 100 fold than diagnosis CT dose. PET / CT scan used very low dose CT attenuation correction in pediatric patients can be helpful in reducing radiation dose.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.567-575
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• 2017

In this study, when diagnosis pancreatic cancer by dual time point PET/CT, we propose SUVm 2.52 as the threshold value for performing the dual time point PET/CT exam. The hypothesis of normal distribution was adopted through data conversion of 60 pancreatic diseases. The proposed SUVm2.52 boundary value showed a significance level that could be applied to both 120 and 180 minutes of delay time scan for pancreatic cancer determination (p<0.05). C-value variation shows that delay time 2 hour test is more useful than delay time 3 hour test. When the SUVm 2.52 is set to the boundary value and the double-time point PET/CT exam is performed, the probability of distinguishing cancer from inflammation in the delayed image is 95%. When the delayed test is performed with the proposed boundary value SUVm 2.52, Compared with general PET / CT scans, it is thought that it may be helpful to distinguish pancreatic cancer.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.44-49
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• 2012

Purpose: In the whole body PET/CT scan, it is natural to lift the patient's arm for its quality improvement. However, when the lesion is located in head and neck, the arms should be located lower. This study was designed to compare the CT effective dose for each arm position applying Automatic Exposure Control (AEC). Materials and Methods: 45 patients who had $^{18}F$-FDG whole body PET/CT scan were studied with Biograph Truepoint 40 (SIEMENS, GERMANY), Biograph Sensation 16 (SIEMENS, GERMANY), Discovery STe 8 (GE healthcare, USA). The CT effective dose of 15 patients for each equipment was measured and comparatively analyzed in both arm-lifted position and lower-arm position. ImPACT v1.0 program was used as the method of measurement for CT effective dose. For the statistics analysis, Paired t-test which paired with SPSS 18.0 statistic program was applied. Results: In the case of arm-lifted, it was measured as $6.33{\pm}0.93mSv$ for Biograph Sensation 16, $8.01{\pm}1.34mSv$ for Biograph Truepoint 40, and $9.69{\pm}2.32mSv$ for Discovery STe 8. When arms are located lower position, it was measure as $6.97{\pm}0.76mSv$, $8.95{\pm}1.85mSv$, $13.07{\pm}2.87mSv$ for each. CT effective dose according to the arm position was 9.2% for Biograph Truepoint 40, 10.5% for Biograph Sensation 16, and 25.9% for Discovery Ste 8. The statistics analysis showed the meaningful difference ($p$<0.05). Conclusion: For the whole body PET/CT case, CT effective dose applying AEC was decreased the radiation exposure of the patients when the arm was lifted for 15.2% of average value. The patient who has no lesion in head and neck would decrease the artifact occurrence in objective part and lower the CT effective dose. Also, for the patient who had lesion in head and neck, the artifact in objective part can be lower by putting the arms down, the fact that CT effective dose increases should be concerned in its whole body PET/CT scan.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2051-2054
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• 2015

Background: Radiation therapy is a key part of the combined modality treatment for Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), which can achieve locoregional control of disease. The 3D-conformal radiation oncology can be extended-field (EFRT), involved-field (IFRT) and involved node (INRT). New techniques have resulted in a smaller radiation field and lower dose for critical organs such as lung heart and breast. Materials and Methods: In our research, we made a virtual simulation for one patient who was treated in four different radiotherapeutic techniques: mantle field (MFRT), EFRT, IFRT and INRT. After delineatiion we compared dose-volume histograms for each technique. The fusion of CT for planning radiotherapy with the initial PET/CT was made using Softver Xio 4.6 in the Focal program. The dose for all four techniques was 36Gy. Results: Our results support the use of PET/CT in radiation therapy planning. With IFRT and INRT, the burden on the organs at risk is less than with MFRT and EFRT. On the other hand, the dose distribution in the target volume is much better with the latter. Conclusions: The aim of modern radiotherapy of HL and NHL is to reduce the intensity of treatment and therefore PET/CT should be used to reduce and not increase the amount of tissue receiving radiation.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.253-255
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• 2008

A 61-year-old man had a F-18 FDG PET/CT scan for evaluation of a common bile duct cancer identified on CT. The PET/CT image showed a hypermetabolic mass in the common bile duct, and a focal area of increased F-18 FDG uptake in segment IV of the liver, which corresponded to a hypoattenuated lesion on non-enhanced CT, and was consistent with hepatic metastasis. The patient underwent choledochojejunostomy with hepatic resection, and pathologic findings were compatible with an eosinophilic abscess in the liver. This case demonstrates that F-18 FDG uptake by an eosinophilic abscess can mimic hepatic metastasis in a patient with a malignancy.

• Fibers and Polymers
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• v.5 no.2
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• pp.122-127
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• 2004

In this study, we evaluated the effect of the molecular weight of the polymer on electrospun poly(ethylene terephthalate) (PET) nonwovens, and their mechanical properties as a function of the linear velocity of drum surface. Polymer solutions and electrospun PET nonwovens were characterized by means of viscometer, tensiometer, scanning electron microscope(SEM), wide angle X-ray diffraction measurement (WAXD) and universal testing machine (UTM). By keeping the uniform solution viscosity, regardless of molecular weight differences, electrospun PET nonwovens with similar average diameter could be obtained. In addition, the mechanical properties of the electrospun PET nonwovens were strongly dependent on the linear velocity of drum surface. From the results of the WAXD scan, it was found that the polymer took on a particular molecular orientation when the linear velocity of drum surface was increased. The peaks became more definite and apparent, evolving from an amorphous pattern at 0 m/min to peaks and signifying the presence of crystallinity at 45 m/min.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.46-51
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• 2008

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasm of the gastrointestinal tract, and can be distinguished from the smooth muscle or neural tumors in approximately 95% of patients by expression of the KIT receptor tyrosine kinase (CD117). GISTs are known to have high malignant potential and none can be labeled definitely as benign. However, GISTs are unresponsive to standard sarcoma chemotherapy, and only complete surgical resection provides chance for cure. Although the imaging modality of choice is enhanced CT scan in patients with GIST, FDG PET can reflect the malignant potential of GIST. Clinical management of patients with GISTs has dramatically changed with the introduction of novel therapeutics, such as imatinib mesylate (Glivec). This has created a need to re-evaluate the existing criteria used to assess treatment response. FDG PET as functional imaging modality proved to be significantly more accurate than CT alone when assessing GIST response to imatinib. And, FDG PET and PET ICT have been found to be highly sensitive in detecting early response, and to be useful in predicting long-term response to imatinib in patients with recurrent or metastatic GISTs.