• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.369-372
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• 2006

Monolithic forging of cask is required continuously. Body-base monolithic forging of cask has advantage of an economical manufacturing process and better reliability for nuclear applications. Through the finite element analysis and parametric study of design variables, those are die angle, groove length and flange thickness, the optimal dimensions of preform and die sets are determined in order to develop a suitable forging process for body-base monolithic forging. To verify the result of finite element analysis, the physical model of 1/30 scale of actual product using plasticine was carried out. The result of this experiment, deformed shapes were very similar to the finite element analysis. As a result of this work, the special piercing method was developed using blank material consisting of a flange, groove and squared part.

• The Korean Journal of Nuclear Medicine
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• v.36 no.1
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• pp.39-45
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• 2002

Clinical application of positron emission tomography (PET) is rapidly increasing for the defection and staging of cancer at whole-body studios performed with the glucose analogue tracer 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG). Although FDG PET cannot match the anatomic resolution of conventional imaging techniques in the liver and the other abdominal organs, it is particularly useful for identification and characterization of the entire body simultaneously. FDG PET can show foci of metastatic disease that may not be apparent at conventional anatomic imaging and can aid in the characterizing of indeterminate soft-tissue masses. Most abdominal cancer requires surgical management. FDG PET can improve the selection of patients for surgical treatment and thereby reduce the morbidity and mortality associated with inappropriate surgery. FDG PET is also useful for the early detection of recurrence and the monitoring of therapeutic effect. The abdominal cancers, such as gastroesophageal cancer, colorectal cancer, liver cancer and pancreatic cancer, are common malignancies in Korea, and PET is one of the most promising and useful methodologies for the management of abdominal cancers.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.1
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• pp.69-73
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• 2015

The study investigated effects of residual stresses and Charpy impact energy on brittle fractures of the butt weld between the valve and the piping, and of the valve body in nuclear power plants via a linear elastic fracture mechanics approach in the ASME B&PV Code, Sec.XI and finite element analysis. Weld residual stress in a butt weld between close check valve and piping, and residual stress in the valve due to casting process were assumed to be proportional to yield strength of base metal. Operating stresses in the butt weld and the valve body were calculated using approximate engineering formulae and finite element analysis, respectively. Applied stress intensity factors were calculated by assuming postulated cracks with specific sizes and then by substituting the residual stresses and the operating stresses into engineering formulae presented in the ASME B&PV Code, Sec.III. Plane strain fracture toughness was derived by using a correlation between Charpy V-notch impact energy and fracture toughness. Structural integrity of the weld and the body against brittle fracture was assessed by using the applied stress intensity factors, plane strain fracture toughness and the linear elastic fracture mechanics approach. As a result, it was identified that the structural integrity was maintained with decreasing the residual stress levels and increasing the Charpy V-notch impact energy.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.49-56
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• 2008

Purpose: Whole body imaging with radioiodine can detect functioning metastases. Non-physiologic I-131 uptake detected on images usually is interpreted as suggesting functioning thyroid metastases. However, extra-thyroidal I-131 accumulation does not always imply thyroid cancer metastases and has been reported in many circumstances. In order to avoid unnecessary therapeutic interventions it is important to distinguish false-positive sites of I-131 localization. We study here to remove false-positive sites around esophagus region on I-131 whole body imaging in patients who were administrated thyroidectomy. Materials and Methods: From April to August in 2007, we had the patients who had visited our department after they received thyroidectomy due to thyroid cancer. They were given I-131, and performed radioiodine body scan after 41 to 50 hours. Patients were whole-body-scanned for the speed of 8 cm per minute. After that, we took anterior and posterior static images around the patients' neck measured by 300 thousand counts per image. We selected 44 patients who had hot spots around neck region, we divided the patients into two groups. One group was given 0.5 L of water and the other group was given 0.5 L of water with 1 g of Vitamin C dissolved. The patients were asked to drink the fluid for one minute in sitting position and after that, we measured 300 kilo counts per image again. We compared prior anterior, posterior static images with anterior, posterior images after the patients had water or water that Vitamin C resolved. Results: In using water, both observer 1 and 2 interpreted 6 patients were washed out. In the water with Vitamin C resolved, observer 1 and 2 interpreted 9 and 8 patients were washed out. Observer 1 and 2 interpreted 6 and 5 patients had 'indeterminate' when they used water. Both observer 1 and 2 interpreted 6 patients had 'indeterminate' when they used water with Vitamin C resolved. When they used water, observer 1 interpreted 10 patients had 'unchanged' and observer 2 interpreted 11 patients had 'unchanged'. Differently, when they used water with vitamin C resolved, observer1 had 8 patients having 'unchanged'and observer 2 had 9. Conclusion: As a result, by making patients drink 0.5 liter of water which has vitamin C resolved helped getting rid of false-positive sites in esophagus. Therefore, based on this study, we believe that drinking water with vitamin C dissolved is very in terms of reducing false-positive hot spot around the esophagus for the iodine-131 whole body scan.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.1
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• pp.30-36
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• 2015

Purpose Whole body bone scan, which makes up a largest percentage of nuclear medicine tests, has high sensitivity and resolution about bone lesion like osteomyelitis, fracture and the early detection of primary cancer. However, any standard for valuation has not yet been created except minimum factor. Therefore, in this study, we will analysis the method which show a quantitative evaluation index in whole body bone scan. Materials and Methods This study is conducted among 30 call patients, who visited the hospital from April to September 2014 with no special point of view about bone lesion, using GE INFINIA equipment. Enumerated data is measured mainly with patient's whole body count and lumbar vertabrae, and the things which include CNR (Contrast to Noise ratio), SNR (Signal to Noise ratio) are calculated according to the mean value signal and standard deviation of each lumbar vertabrae. In addition, the numerical value with the abdominal thickness is compared to each value by the change of scan speed and tissue equivalent material throughout the phantom examination, and compared with 1hours deleyed value. Completely, on the scale of ten, 2 reading doctors and 5 skilled radiologists with 5-years experience analysis the correlation between visual analysis with blind test and quantitative calculation. Results The whole body count and interest region count of patients have no significant correlation with visual analysis value throughout the blind test(P<0.05). There is definite correlation among CNR and SNR. In phantom examination, Value of the change was caused by the thickness of the abdomen and the scan speed. And The poor value of the image in the subject as a delay test patient could be confirmed that the increase tendency. Conclusion Now, a standard for valuation has not been created in whole body bone scan except minimum factor. In this study, we can verify the significant correlation with blind test using CNR and SNR and also assure that the scan speed is a important factor to influence the imagine quality from the value. It is possible to be some limit depending on the physiology function and fluid intake of patient even if we progress the evaluation in same condition include same injection amount, same scan speed and so on. However, that we prove the significant evaluation index by presenting quantitative calculation objectively could be considered academic value.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.4
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• pp.523-531
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• 2022

The International Atomic Energy Agency (IAEA) entails independent decision-making for the safety supervision of civil nuclear facilities. To evaluate and review the safety of nuclear facilities, the national regulatory body usually consults independent institutions or external committees. Technical Support Organizations (TSOs) include national laboratories, research institutions, and consulting organizations. Support from professional organizations in other countries may also be required occasionally. Most of the world's major nuclear power countries adopt an independent nuclear safety supervision model. Accordingly, China has continuously improved upon the construction of such a system by establishing the National Nuclear Safety Administration (NNSA) as the decision-making department for nuclear and radiation safety supervision, six regional safety supervision stations, the Nuclear and Radiation Safety Center (NSC), a nuclear safety expert committee, and the National Nuclear and Radiation Safety Supervision Technology R&D Base, which serves as the test, verification, and R&D platform for providing consultation and technical support. An R&D system, however, remains to be formed. Future endeavors must focus on improving the technical support capacity of these systems. As an enhancement from institutional independence to capability independence is necessary for ensuring the independence of China's nuclear safety regulatory institution, its regulatory capacity must be improved in the future.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.543-544
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1200-1201
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.369-369
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• 2002

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.72-77
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• 2013

Purpose: Whole-body PET using radiopharmaceutical is one of the imaging study methods for physiological changes of body. High specificity of the PET-CT examination is used to detect an early stages of cancer and metastatic cancer by imaging a physiological changes. During the imaging process, PET image has been characterized by a relatively low image quality due to its low sensitivity and the acquisition of random and scatter coincidences as well as patients figure. Therefore, the image quality as the changes of the acquisition times of patient weight was evaluated in this study. Materials and Methods: Thirty patients who presented to our hospital were enrolled. They were divided to normal, overweight, and obese group using BMI index, respectively. The patients with a liver disease and diabetes were excluded. $^{18}F-FDG$ was administered to the patients as 5.2 MBq per kg. After an hour from an injection, image acquisition was obtained as List mode in a part of liver in 1 bed. SNR (signal-to-noise ratio) of each groups acquisition times were confirmed from the calculated radiation counts and random fractions. The statistical significance of three groups was confirmed through one-way ANOVA test. On the basis of the counts of 2 minutes on normal group, the SNR of overweight group and obese group were compared. Results: The SNR were increased with loger aquisition time in 3 groups. In the condition of same acquisition time, the SNR had a statistical significance (P<0.05). The SNR were decreased to the normal, overweight, and obese, respectively. Liver activity had no significance difference on each group and RF had the significance differences (P<0.05). On the basis of the counts of 2 minutes on normal group, there were no statistical significance in a three minute acquisitions of overweight group and two minute acquisitions of obese group (P=0.150). Conclusion: In this study, the administrated amount of radiation dose did not adjust as the change of the patients weight. Increasing the acquisition time when the administration of the same amount of dose was able to get a good result of SNR. When the Based 2 minute on normal group, if overweight and obese case the increased acquisition time of 3 minute was able to obtain a similar SNR. On the basis of the normal group, the acquisition times of overweight and obese group were increased to 3 minutes per bed and the SNR were similar to the normal group.