• Journal of radiological science and technology
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• v.38 no.3
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• pp.305-313
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• 2015

After Fukushima Daiichi nuclear disaster in 2011, study and maintenance of monitoring systems have been made at home and abroad. As concerns about radioactive contamination of water have increased in Korea, update of maintenance of managing radioactive materials in water is being made mainly by Ministry of Environment. In this study, we analysed current state of monitoring system modification in Japan, the country directly involved and neighboring country. According to the result, Japan modified the legislations first. Then Ministry of Education, Culture, Sports, Science and Technology (MEXT) provides theoretical background of radiological monitoring. And Ministry of the Environment actually watches state of water pollution in public waters and underground water. Finally related agencies like local government are monitoring current state of radioactive contamination in water environment. By region, local monitoring stations share the investigation of the whole country. Also, additional monitoring is running around nuclear facilities. After Fukushima disaster, monitoring for area near Fukushima is added. Among the reference levels, management target value of drinking water and tap water is 10 Bq/kg, and those of public water and underground water are 1 Bq/L. Measuring intervals varied from every hour to once a year, regularly or irregularly depending on the investigation. The main measuring items are air dose rate, gross ${\alpha}$, gross ${\beta}$, ${\gamma}$ radionuclide, Cs-134, Cs-137, Sr-89, Sr-90, I-131, and so on. In comparison, regulations about general public water in Korea need to be modified, while those about area near nuclear facility and drinking water are organized well. In future, therefore, domestic system would be expected to be modified with making reference to the guidelines like WHO's one. As good case of applying international guideline to domestic environment, Japanese system could be a reference when general standard of radioactivity in public water is made in Korea.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.129-135
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• 1999

Purpose : This study evaluated early bowel complications in cervix cancer patients, following external radiotherapy (ERT and high dose rate intracavitary radiation (HDR ICR). Factors affecting the risk of developing early bowel complications and its incidence are analyzed and discussed Materials and Methods : The study is the retrospective review of 66 patients who received radiotherapy at Chungbuk National University Hospital from April 1994 to December 1998. The patients underwent 41.4 or 50.4 Gy ERT according to FIGO stage and tumor size, then A point dose was boosted to 71.4 or 74.4 Gy using a remotely controlled afterloading Buchler HDR ICR. The EORTC/RTOG morbidity criteria were used to grade early bowel complications, which are valid from day 1, the commencement of therapy, through day 90. The actuarial incidence, severity of complications were investigated and clinical pretreatment factors relevant to complications were found through univariate (Wilcoxon) and multivariate (Cox proportional hazard model) analysis. Results : Of the 66 patients, 30 patients (46$\%$) developed early bowel complications; 25 patients (38$\%$) with grade 1 or 2, 4 patients (0$\%$) with grade 3 and 1 patient (2$\%$) with grade 4. The complications usually began to occur 3 weeks after the commencement of radiotherapy. The actuarial incidence of early bowel complications was 41$\%$ at 10 weeks. The early bowel complications were associated significantly with an old age and a history of previous abdomino-pelvic surgery. All three patients who had a protracted overall treatment time (about 2 weeks) due to severe bowel complication, suffered from pelvic recurrences. Conclusion : Forty six percent of patients experienced early bowel complications, most of which were grade 1 or 2 and relieved spontaneously or by medication. The patients with an old age or a previous surgery have a high probability of early complications and they may be less compliant with planned radiotherapy. So more careful precaution is necessary for these patients.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.277-286
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• 2015

Diagnostic radiation devices that is used in the country has reached to 78,000 units. When used for human subjects diagnostic purposes, it is subject to Medical Service Act, when used in diagnostic purposes in animal subjects, the subject to Veterinarians Act. When used for other purposes are subject to the Nuclear Safety Act. Even the same radiation devices varies the legislation that is applied depending on the intended use and object. Diversified been p rovisions a re necessary compared to t he analysis o f l egal content in o rder t o prevent confusion of the legislation is a matter to be applied. It is a qualitative study that Nuclear Safety Act, Medical Service Act and Veterinarians Act administrative procedures for the introduction of the applied diagnostic radiation devices, safety inspection, human resources management, area management and the content related to administrative punishment. The Nuclear Safety Act sub-provisions, the introduction of diagnostic radiation generating devices, there are many complex and complete requirements administrative procedures on the concept of a permit. Inspection of safety associated with the use, would be subject to periodic inspection auditing characteristics over the entire field of radiation safety management. It must receive court regular education for the safety administrator and workers. Unlike the reference of the radiation dose rate to specify the radiation controlled area there is a measurement obligation of radiation dose rate. Unlike the reference of the radiation dose rate to specify the radiation controlled area there is a measurement obligation of radiation dose rate. Quantitative difference of administrative punishment that is imposed when legislation violation has reached up to 10 times, over the entire field, the largest burden of radiation safety management at the time of application of the Nuclear Safety Act sub provisions. And it is applied differently depending on the purpose and the imaging target using the same diagnostic radiation devices. Depending on the use mainly under the current legal system, radiation can be lacking in fairness of the contents of the legislation for safety management, there is a risk of confusion. Alternatives such as centralized and standardization of legislation by diagnostic radiation devices use is expected to be necessary.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.139-144
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• 1969

1. In order to obtain useful mutants such as early maturity, resistance to lodging, high protein and oil content, and capability of high yield, dormant seeds of two soybean varieties, Jang Dan Baik Mok and Clark, were treated with ${\gamma}$-ray, Ethyl Methane Sulfonate(EMS), Ethylene Imine(EI)and combinations of ${\gamma}$-ray and EMS or EI. 2. The germination rate and survival rate in a variety Jang Dan Baik Mok were significantly decreased with ${\gamma}$-ray treatment while it was not the same in the Clark variety. A significant decrease for seedling height measured at 14 and 21 days after sowing was found with the increase of ${\gamma}$-ray dose in both varieties. 3. Germination rates in both varieties were significantly decreased as EI concentration increases, particularly severe damage in germination was observed at 0.008 Mo. concentration. Germination rate damages were found with EMS concentration increases in the variety Jang Dan Baik Mok while no regular responses in seedling height were observed in the variety Clark. 4. Germination rate was significantly lowered with the combined treatment of EMS and ${\gamma}$-ray 24KR than that of EMS alone. In the treatments of ${\gamma}$-ray with three levels of EI concentration, the combined treatments except 24KR+EI 0.002 Mol. resulted in better germination than of EI alone. In both varieties, significant reduction in seedling height was observed in the combined treatments of ${\gamma}$-ray with various concentrations of EMS, whereas stimulation effect on seedling height was found with treatment of ${\gamma}$-ray EI +0.08Mol. 5. Germination rate, survival rate, and plant height as criteria of radio sensitivity, variety Jang Dan Baik Mok is moze sensitive to ${\gamma}$-ray, EMS, and EI than the variety Clark, and the varietal difference in responsibility to mutagen may be due to the genetic-constitution of the varieties.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.17-21
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• 2014

Purpose With the recent rise of social issue regarding radiation exposure, attention to medical radiation use has been placed under a great spotlight. During PET-CT examination, generally about 40% more of $^{18}F$-FDG is used than EANM recommendation. While maintaining the diagnostic test result, we hope to find optimal injection dose to minimize the $^{18}F$-FDG in patients by utilizing the latest PET-CT scanner which is equiped with the newest technology. Materials and Methods During this experiment, the Biograph Truepoint 40 (siemens, USA) installed in 2007 and mCT 64 (siemens, USA) installed in 2011 were used and evaluated NECR (noise-equivalent counting rate) by using a scatter phantom. For the image quality evaluation of each scanner, we injected 3.7, 4.44 and 5.18 MBq/kg of $^{18}F$-FDG in NEMA IEC Body Phantom and also evaluated SNR between two scanners by using the data acquired at 60, 70, 80, 90, 100, 110 and 120 sec per bed. For the clinical evaluation, actual data of patients who were injected $^{18}F$-FDG 3.7, 4.44, 5.18 MBq/kg were used to compare SNR and draw a final result. Results As a result, mCT 64 peak NECR value was 1.65e+005, which is 10% higher than Turepoint 40. SNR values using the IEC body phantom was 17.9%, 17.4% and 17.1% higher in $^{18}F$-FDG 3.7 MBq/kg, 4.44 MBq/kg and 5.18 MBq/kg. In clinical patients, SNR values of the image mCT 64 was 16.5, which is 25% higher than Turepoint 40 scanner. Conclusion To draw a conclusion from the test result of this experiment, the same quality of SNR could be attained even with 10% reduced injection dose, if when the duration is extended by 10 sec/bed. This optimal result was possible due to enhanced equipment. The NECR (one of the equipment's performance assessment criteria for the scanner) increased by 10% and the SNR (one of the image quality assessment criteria) also increased by 17.5%. Therefore, we can expect to reduce the injection dose without deterioration of image quality. In consequence, it will also help to decrease the patient's anxiety of the radiation exposure.

• The Journal of Engineering Geology
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• v.15 no.2 s.42
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• pp.213-227
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• 2005

This study aims to assess the problems with investigation method and to suggest the complementary solutions by comparing the predicted data from surface investigation with the outcome data from underground cavern. In the study area, one(NE-1) of 6 fracture zones predicted during the surface investigation was only confirmed in underground caverns. Therefore, it is necessary to improve the confidence level for prediction. In this study, the fracture classification criteria was quantitatively suggested on the basis of the BHTV images of NE-1 fracture zone. The major orientation of background fractures in rock mass was changed at the depth of the storage cavern, the length and intensity were decreased. These characteristics result in the deviation of predieted predicted fracture properties and generate the investigation bias depending on the bore hole directions and investigated scales. The evaluation of hydraulic connectivity in the surface investigation stage needs to be analyze by the groundwater pressures and hydrochemical properties from the monitoring bore hole(s) equipped with a double completion or multi-packer system during the test bore hole is pumping or injecting. The hydraulic conductivities in geometric mean measured in the underground caverns are 2-3 times lower than those from the surface and furthermore the horizontal hydraulic conductivity in geometric mean is six times lower than the vertical one. To improve confidence level of the hydraulic conductivity, the orientation of test hole should be considered during the analysis of the hydraulic conductivity and the methodology of hydro-testing and interpretation should be based on the characteristics of rock mass and investigation purposes.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.147-153
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• 2005

Purpose : We should use a computed tomography-simulator for the body measure and compensator manufacture process was practiced with TBI's positioning in process and to estimate the availability.,Materials and Methods : Patient took position that lied down. and got picture through computed tomography-simulator. This picture transmitted to Somavision and measured about body measure point on the picture. Measurement was done with skin, and used the image to use measure the image about lungs. We decided thickness of compensator through value that was measured by the image. Also, We decided and confirmed position of compensator through image. Finally, We measured dosage with TLD in the treatment department.,Results : About thickness at body measure point. we could find difference of $1{\sim}2$ cm relationship general measure and image measure. General measure and image measure of body length was seen difference of $3{\sim}4$ cm. Also, we could paint first drawing of compensator through the image. The value of dose measurement used TLD on head, neck, axilla, chest(lungs inclusion), knee region were measured by $92{\sim}98%$ and abdomen, pelvis, inquinal region, feet region were measured by $102{\sim}109%$.,Conclusion : It was useful for TBI's positioning to use an image of computed tomography-simulator in the process. There was not that is difference of body thickness measure point, but measure about length was achieved definitely. Like this, manufacture of various compensator that consider body density if use image is available. Positioning of compensator could be done exactly. and produce easily without shape of compensator is courted Positioning in the treatment department could shortened overall $15\{sim}20$ minute time. and reduce compensator manufacture time about 15 minutes.

• Journal of Korean Elementary Science Education
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• v.24 no.3
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• pp.259-267
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• 2005

This study was to investigate the elementary students' preconception on the brightness of electric bulb and degree of consistency on their preconceptions. Participants were 160 students of fifth graders in Seoul area. They had already teamed about the brightness of series circuit and parallel circuit of batteries. After they solved six problems in the same context, we provided them a pair of circuit which was an anomalous situation. And then they conducted CCLT (Cognitive Conflict Level Test). Elementary school students showed various preconceptions when they explained the light of bulb of two Simple electric Circuits. Many Students Consistently Showed the Scientific misconceptions like 'the light of bulb of two simple electric circuits was that the more batteries and the fewer bulbs were brighter.' The level of consistency that students presented scientific misconceptions was grouped all of four, such as 'high, middle, low, and nothing.' Therefore the higher scientific achievement they have, the higher consistency they have. As the students had high consistency level, they revealed high cognitive conflict level significantly. This high consistency will help them to change their preconception on the brightness of electric bulb and their cognitive conflict.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.671-677
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• 2017

In this study, scattering factors affecting the quality of medical images were quantitatively analyzed and investigated. MCNPX simulation was conducted by using ANSI phantom, made of tissue equivalent materials, to calculate the scattering ratio occurred by the increase of the object thickness. Then, the result of the simulation was compared with the result of actual radiation measurement. In addition, we evaluated the image quality by the RMS evaluation, RSD and NPS analysis using X-ray images acquired with increasing object thickness. Furthermore, the scattering ratio was analyzed by increasing the thickness of acrylic phantom on chest phantom. The result showed that the scattering ratio was increased to 57.2%, 62.4%, and 66.8% from 48.9%, respectively, when the acrylic phantom thickness was increased by 1 inch from 6.1 inches. The results of MCNPX simulation and the actual measured scattering dose showed similar results. Also, as a result of RMS measurement from acquired x-ray images, the standard deviation decreased as the object thickness increased. However, in the RSD analysis considering the average incident dose, the results were increased from 0.028 to 0.039, 0.051, 0.062 as the acrylic phantom thickness was increased from 6.1 inches to 7.1 inch, 8.1 inch, and 9.1 inch, respectively. It can be seen that the increase of the scattering effect due to the increase of the object thickness reduces the SNR. Also, the NPS results obtained by measuring scattered radiation incident on the detector resulted in the increase of the noise as the object thickness increased.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.201-205
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• 2007

Purpose: This retrospective study was conducted to assess outcome and to determine the prognostic factors in patients with a desmoid tumor treated with postoperative radiotherapy. Materials and Methods: Twenty-seven patients with a desmoid tumor who were treated with postoperative radiotherapy between June 1984 and October 2005 were analyzed. There were 13 male and 14 female patients. The age of the patients ranged from 3 to 79 years (median age, 28 years). Tumors were located in an extra-abdominal area (21 cases), and in the abdominal walls (6 cases). The tumor size ranged from 2.5 to 25 cm (median size, 7.5 cm) in the largest linear dimension. Thirteen cases received radiotherapy after initial surgery, and 14 recurrent cases received radiotherapy after additional surgery. The total radiation dose given was $45{\sim}66$ Gy (median dose, 59.4 Gy), and the fraction size was $1.8{\sim}2.0$ Gy. Results: The median follow-up period was 61 months (range, $12{\sim}203$ months). Two patients developed local progression and six patients experienced local recurrence. The 5-year disease-free survival rate and the 5-year progression-free survival rate were 61 % and 70%, respectively. Wide local excision was associated with better disease free survival with statistical significance (p=0.028). Radiotherapy after initial surgery (p=0.046) and a higher radiation dose of more than 60 Gy (p=0.049) were associated with better progression free survival with statistical significance. At the time of the last follow-up, the number of additional surgeries was higher in patients that received radiotherapy after reoperation (p<0.001). Conclusion: Radiotherapy after the initial operation improved local control and decreased the number of subsequent operations. Thus, postoperative radiotherapy after an initial operation is recommended in patients with a high risk of recurrence for a desmoid tumor.