• Progress in Medical Physics
• /
• v.17 no.3
• /
• pp.136-143
• /
• 2006

The respiratory gating radiation therapy which Irradiates only in the stable respiratory period with analyzing the periodic motion of a reflective marker on the patient's abdomen has been applied to the precise radiation treatment in order to minimize the effect of organ motion induced by the respiration. This respiratory gating system establishes irradiation region using the amplitude-based or phase-based method. Although phase-based method Is preferred because of the stability in the real treatment conditions, it has some limits to explain the exact correlation between the marker motion and organ motion. Even when the variation of amplitude which can introduce target motion considered as an error is produced, the phase-based method has the possibility to irradiate including the error positions. In this study, the error analysis program was developed for the verification of the tumor position's variation correlated with the variation of marker's amplitude which can be occurred during a phase-based respiratory sating treatment. The analysis program was tested with a virtual treatment record file and with a record file using moving phantom which were modified considering the irregular amplitude's variation simulating the real clinical situations. In both cases, accurate discrimination of error points and error calculation were produced. When the treatment record files of a real patient were analyzed with the program, the accurate recognition and calculation of the error points were also verified. The analysis program developed in this study will be applied as a useful tool for the analysis of errors due to the irregular variation of patients' respiration during the phase-base respiratory gating radiation treatment.

• Progress in Medical Physics
• /
• v.17 no.3
• /
• pp.179-186
• /
• 2006

Purpose: Photon beam data of linear accelerators in Korea are collected, analyzed, and a simple method for checking and verifying the dose calculations in a TPS are suggested. Materials and Methods: Photon beam data such as output calibration condition, output factor, wedge factor, percent depth dose, beam profile, and beam quality were collected from 26 institutions in Korea. In order to verify the accuracy of dose calculation, ten sample planning tests were peformed. These Include square, elongated, and blocked fields, wedge fields, off-axis dose calculation, SSD variation. The planned data were compared to that of manual calculations. Results: The average and standard deviation of photon beam quality for 6, 10, and 15 MV were $0.576{\pm}0.005,\;0.632{\pm}0.004,\;and\;0.647{\pm}0.006$, respectively. The output factors of 6 MV photon beam measured at depth of dose maximum for $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm\;were\;0.944{\pm}0.006,\;1.031{\pm}0.006,\;and\;1.055{\pm}0.007$. For 10 MV photon beam, the values were $0.935{\pm}0.006,\;1.031{\pm}0.007,\;1.054{\pm}0.0005$. The collected data were not enough to calculate average, the output factors for 15MV photon beam with field size of $5{\times}5cm,\;15{\times}15cm,\;20{\times}20cm\;were\;0.941{\pm}0.008,\;1.032{\pm}0.004,\;1.049{\pm}0.014$. There was seven institutions $e{\times}ceeding$ tolerance when monitor unit values calculated from treatment planning system and manually were compared. The measured average MU values for the machines calibrated at SAD setup were 3 MU and 5 MU higher than the machines calibrated at SSD for 6 MV and 10 MV, respectively except the wedge case. When the wedges were inserted, the MU values to deliver 100 cGy to 5 cm depends on manufactures. When the same wedge angle was used, Siemens machine requires more MUs then Varian machine. Conclusion: In this study, photon beam data are collected and analyzed to provide a baseline value for chocking beam data and the accuracy of dose calculation for a treatment planning system.

• Analytical Science and Technology
• /
• v.27 no.3
• /
• pp.172-180
• /
• 2014

Fenpyrazamine which is a pyrazole fungicide class for controlling gray mold, sclerotinia rot, and Monilinia in grapevines, stone fruit trees, and vegetables has been registered in republic of Korea in 2013 and the maximum residue limits of fenpyrazamine is set to grape, peach, and mandarin as 5.0, 2.0, and 2.0 mg/kg, respectively. Very reliable and sensitive analytical method for determination of fenpyrazamine residues is required for ensuring the food safety in agricultural products. Fenpyrazamine residues in samples were extracted with acetonitrile, partitioned with dichloromethane, and then purified with silica-SPE cartridge and eluted with hexane and acetone mixture. The purified samples were determined by HPLC-UVD and confirmed with LC-MS and quantified using external standard method. Linear range of fenpyrazamine was between $0.1{\sim}5.0{\mu}g/mL$ with the correlation coefficient (r) 0.999. The average recovery ranged from 71.8 to 102.7% at the spiked level of 0.05, 0.5, and 5.0 mg/kg, while the relative standard deviation was between 0.1 and 7.3%. In addition, limit of detection and limit of quantitation were 0.01 and 0.05 mg/L, respectively. The results revealed that the developed and validated analytical method is possible for fenpyrazamine determination in agricultural product samples and will be used as an official analytical method.

• Journal of Food Hygiene and Safety
• /
• v.29 no.3
• /
• pp.170-180
• /
• 2014

The aim of this study was to investigate pesticide residues in 2,877 market vegetables in the northern area of Seoul in 2013. Pesticide residues in the samples were analysed by multiresidue method for 285 pesticides using GC-ECD/NPD and HPLC-DAD/FLD. 385 samples(13.4%) were detected with pesticide residues at or below MRL, and 15 samples(0.5%) were found to detect pesticide residues exceeding MRL. The most frequently detected samples were sedum(63.6%), chamnamul(45.8%), leek(44.5%) and green&red pepper(30.8%). Among the 15 violated samples, leek(5 cases) and welsh onion(4 cases) showed the highest violation rate. A total of 74 samples(18.5%) contained multiple pesticide residues in one vegetable. Procymidone, chlorofenapyr and cypermethrin were the pesticide most frequently found. As a tool of risk assessment through the consumption of pesticide detectable agricultural products, the ratio of estimated daily intake (EDI) to acceptable daily intake (ADI) was calculated into the range of 1.05~28.61%. The results have meant that there was no health risk through dieting commercial agricultural products detected with pesticide residues.

• Journal of Food Hygiene and Safety
• /
• v.35 no.3
• /
• pp.243-251
• /
• 2020

In this study, we investigated pesticide residues in 207 agricultural products distributed by direct trade in the northern area of Gyeonggi Province. A total of 94 general agricultural products and 113 eco-friendly agricultural products collected from local grocers and cooperative stores were analyzed by multiresidue method for 263 pesticides using GC (gas chromatography)/ECD (electron capture detector), GC/NPD (nitrogen phosphorus detector), GC-MS/MS (tandem mass spectrometry), LC (liquid chromatography)/PDA (photodiode array detector), LC/FLD (fluorescence detector), LC-MS/MS. All samples showing pesticide residues were general agricultural products collected from local food stores. The pesticide residue levels of 14 samples (6.8%) were below the maximum residue limits (MRLs) and one of them (0.5%) exceeded the MRLs. Sixteen pesticides were detected from samples of the following produce items: spinach, young cabbage, perilla leaves, mallow, cucumber, chives and water dropwort. The safety of the detected pesticides was assessed by monitoring the daily intake estimate (EDI) and the daily intake allowance (ADI) based on the amount of pesticides detected. The ADI percentage range (the ratio of EDI to ADI) was 0.0134-61.6259% and there was no health risk connected with consuming agricultural products in which pesticide residues were detected.

• The Korean Journal of Air & Space Law and Policy
• /
• v.25 no.2
• /
• pp.163-199
• /
• 2010

A frequent flyer program is a loyalty program offered by many airlines. Typically, airline customers enrolled in the program accumulate frequent flyer miles corresponding to the distance flown on that airline or its partners. There are other ways to accumulate miles. In recent years, more miles were awarded for using co-branded credit and debit cards than for air travel. Acquired miles can be redeemed for free air travel; for other goods or services, such as travel class upgrades, airport lounge access or priority bookings. The first modern frequent flyer program was created Texas International Airlines in 1979. This program was also adopted in Korean Air in 1984. Since then, the mileage programs have grown enormously. As of June 2009, the total member of two national airlines in Korea had been over thirty million. However, accumulated miles could be burden of airlines, because the korean corporations should record the annual financial report the accumulate mileage on a liability account by 'the international financial report standards(IFRS)' next year. The korean airlines need to minimize the accumulated miles, so that for instance Korean Airlines SKYPASS-miles expire 5 years after being earned. It means that miles earned on or after July 2008 will expire after five years if unredeemed. Thus, this paper attempt to analyze the unfairness of the mileage rules of korean airlines by examining a specific portion of the conditions relating to consumer protection, because many mileage users has difficulties using mileage programs and complained the amendment of the mileage rules. In conclusion, the contemporary mileage rules in Korea are rather unsatisfactory, because airlines is not only recognizing a mileage into a kind of benefit but also denying inheritance of mileage and the legal nature of mileage as a property right. It is necessary to amend relevant mileage rules in view of consumer protection, because air mileage is not simple benefit but a right of mileage user.

• Progress in Medical Physics
• /
• v.21 no.1
• /
• pp.113-119
• /
• 2010

Software for GafChromic EBT2 film dosimetry was developed in this study. The software provides film calibration functions based on color channels, which are categorized depending on the colors red, green, blue, and gray. Evaluations of the correction effects for light scattering of a flat-bed scanner and thickness differences of the active layer are available. Dosimetric results from EBT2 films can be compared with those from the treatment planning system ECLIPSE or the two-dimensional ionization chamber array MatriXX. Dose verification using EBT2 films is implemented by carrying out the following procedures: file import, noise filtering, background correction and active layer correction, dose calculation, and evaluation. The relative and absolute background corrections are selectively applied. The calibration results and fitting equation for the sensitometric curve are exported to files. After two different types of dose matrixes are aligned through the interpolation of spatial pixel spacing, interactive translation, and rotation, profiles and isodose curves are compared. In addition, the gamma index and gamma histogram are analyzed according to the determined criteria of distance-to-agreement and dose difference. The performance evaluations were achieved by dose verification in the $60^{\circ}$-enhanced dynamic wedged field and intensity-modulated (IM) beams for prostate cancer. All pass ratios for the two types of tests showed more than 99% in the evaluation, and a gamma histogram with 3 mm and 3% criteria was used. The software was developed for use in routine periodic quality assurance and complex IM beam verification. It can also be used as a dedicated radiochromic film software tool for analyzing dose distribution.

• The Journal of Engineering Geology
• /
• v.15 no.2 s.42
• /
• pp.213-227
• /
• 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
• /
• v.21 no.2
• /
• pp.75-82
• /
• 2009

Purpose: Measure the ozone level in the treatment room while treating a patient so want to know the degree of contamination caused by ozone occurrence. Materials and Methods: Use the linear accelerator (Clinac 21EX, Varian, USA) with the ozone meter (series-200, aeroQual, New Zealand) and water phantom (Wellhofer, IBA, Germany) is irradiated the radiation so that measured the ozone generation level according to MU, dose-rate, SSD, field size, energy, delay time and put the ozone meter in the treatment room actually while treating a patient so measured the daily ozone level variation. Results: While irradiating the radiation, degree of ozone contamination wasn't affected by the energy but mostly in case of electron beam, ozone level was higher than photon beam. The higher dose-rate (0.016~0.025 ppm/hr), the farther SSD (0.018~0.030 ppm/hr), the wider field sizes (0.016~0.025 ppm/hr), the more MU (0.018~0.046 ppm/hr), it occurred high ozone level. Ozone decrement according to delay time changed the background level (0.016 ppm/hr) after elapsed time of 10 minutes from irradiating radiation. And daily ozone occurrence level in the treatment room was below ozone standard level 0.1 ppm/hr (average:0.06 ppm/8 hr) but it could confirm that ozone generation level was included the level (max:0.038 ppm/hr) above 0.02 ppm/hr which patient could perceive. Conclusion: Through ozone level according to variation of certain conditions, actually in the treatment room ozone generation level didn't damaged to patients or workers. Commonly peoples think that ozone was harmful gas but it thought that small amount of ozone generation level while treating a patient was beneficial in the treatment room through air purge action of pathogenic germ or virus sterilization.

• Korean Journal of Food Science and Technology
• /
• v.36 no.1
• /
• pp.14-18
• /
• 2004

Analysis methods of artificial sweeteners, aspartame, acesulfame potassium, sodium saccharin, and sucralose isolated from foods were developed using high performance liquid chromatography, HPLC conditions for aspartame, acesulfame potassium, and sodium saccharin were: column, Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$; mobile phase, 0.05M sodium phosphate monobasic : acetonitrile (9 : 1, pH 3.5, containing 0.01M tetrapropylammonium hydroxide); detector, UV detector at 210 nm. HPLC condition for sucralose were : column, Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$; mobile phase, water:methanol (7 : 3); detector, refractive index detection (sensitivity = 16). Recoveries of artificial sweeteners in foods including soft drinks, fruit and vegetable beverages, alcoholic beverages, fermented milk beverages, soybean milk, ice cream, snacks, chewing gums, jam, honey, kimchi salted food, special dietary products, processed fish products, candies, food additive mixtures, chocolate and cocoa were 76.1-101.3%, 82.3-103.2%, 83.1-103.7%, and 80,6-99.5% for aspartame, acesulfame potassium, sodium saccharin, and sucralose, respectively.