1.Analysis of Low MU Characteristics of Siemens Primus Linear Accelerator using Diode Arrays for IMRT QA.
Juree KIM ; Rena LEE ; Kyung Ja LEE
Korean Journal of Medical Physics 2008;19(3):164-171
One of the most important task in commissioning intensity modulated radiotherapy (IMRT) into a clinic is the characterization of dosimetry performance under small monitor unit delivery conditions. In this study, method of evaluating dose monitor linearity, beam flatness and symmetry, and MLC positioning accuracy using a diode array is investigated. Siemens Primus linear accelerator (LA) with 6 and 10 MV x-rays was used to deliver radiation and the characteristics were measured using a multi array diodes. Monitor unit stabilities were measured for both x-ray energies. The dose linearity errors for the 6 MV x-ray were 2.1, 3.4, 6.9, 8.6, and 15.4 % when 20 MU, 10 MU, 5 MU, 4 MU, and 2 MU was delivered, respectively. Greater errors were observed for 10 MV x-rays with a maximum of 22% when 2 MU was delivered. These errors were corrected by adjusting D1_C0 values and reduced to less than 2% in all cases. The beam flatness and symmetry were appropriate without any correction. The picket fence test performed using diode array and film measurement showed similar results. The use of diode array is a convenient method in characterizing beam stability, symmetry and flatness, and positioning accuracy of MLC for IMRT commissioning. In addition, adjustment of D1-C0 value must be performed when a Siemens LA is used for IMRT because factory value usually gives unacceptable beam stability error when the MU/segment is smaller than 20.
Organothiophosphorus Compounds
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Particle Accelerators
2.The influence of acute intoxication of acephate on some antioxydant enzymes in rabbit’s blood red cells
Journal of Practical Medicine 2003;463(10):77-79
Acephate with dose of oral 100mg/kilo weigh for 1 time made acute intoxication in rabbits and changes in activity clearly with some parameters: plasma ChE enzyme activity reduce about 41% after 3 to 6 hours intoxication, ability recover after 24 hours but after 48hours still hasn’t get medium level. MetHb rate increase highest at 6 hours and after reduce gradually to nomal level at 48 hours. There have change in acid-base balance, rabbits on infect alkali breathing at 3 hours, transform acid poisoning at 6 hours and infect combine alkali at 24hours and 48hours. Erythrocyte SOD enzyme activity reduce. Urea, glucoza, uric acid level increase significant after 3-6hours intoxication and back to normal nearly after 48hours
Organothiophosphorus Compounds
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Poisoning
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Enzymes
3.Evaluation of Factors Used in AAPM TG-43 Formalism Using Segmented Sources Integration Method and Monte Carlo Simulation: Implementation of microSelectron HDR Ir-192 Source.
Woo Sang AHN ; Won Woo JANG ; Sung Ho PARK ; Sang Hoon JUNG ; Woon Kap CHO ; Young Seok KIM ; Seung Do AHN
Korean Journal of Medical Physics 2011;22(4):190-197
Currently, the dose distribution calculation used by commercial treatment planning systems (TPSs) for high-dose rate (HDR) brachytherapy is derived from point and line source approximation method recommended by AAPM Task Group 43 (TG-43). However, the study of Monte Carlo (MC) simulation is required in order to assess the accuracy of dose calculation around three-dimensional Ir-192 source. In this study, geometry factor was calculated using segmented sources integration method by dividing microSelectron HDR Ir-192 source into smaller parts. The Monte Carlo code (MCNPX 2.5.0) was used to calculate the dose rate D(r,theta) at a point (r,theta) away from a HDR Ir-192 source in spherical water phantom with 30 cm diameter. Finally, anisotropy function and radial dose function were calculated from obtained results. The obtained geometry factor was compared with that calculated from line source approximation. Similarly, obtained anisotropy function and radial dose function were compared with those derived from MCPT results by Williamson. The geometry factor calculated from segmented sources integration method and line source approximation was within 0.2% for r> or =0.5 cm and 1.33% for r=0.1 cm, respectively. The relative-root mean square error (R-RMSE) of anisotropy function obtained by this study and Williamson was 2.33% for r=0.25 cm and within 1% for r>0.5 cm, respectively. The R-RMSE of radial dose function was 0.46% at radial distance from 0.1 to 14.0 cm. The geometry factor acquired from segmented sources integration method and line source approximation was in good agreement for r> or =0.1 cm. However, application of segmented sources integration method seems to be valid, since this method using three-dimensional Ir-192 source provides more realistic geometry factor. The anisotropy function and radial dose function estimated from MCNPX in this study and MCPT by Williamson are in good agreement within uncertainty of Monte Carlo codes except at radial distance of r=0.25 cm. It is expected that Monte Carlo code used in this study could be applied to other sources utilized for brachytherapy.
Anisotropy
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Brachytherapy
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Organothiophosphorus Compounds
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Uncertainty
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Water
4.Factors Associated with Stages of Exercise Behavior Change of Residents in a Community.
Journal of Korean Academy of Community Health Nursing 2012;23(3):316-326
PURPOSE: This study was to identify the factors associated with stages of exercise behavior change of residents in a community on the basis of the Transtheoretical Model. METHODS: Data were collected from 520 residents of a community using a self-report questionnaire. The survey variables comprised the stages of exercise behavior change, the process of change, decisional balance and self efficacy. RESULTS: There were significant differences in the process of change, decisional balance and self efficacy by the stages of exercise behavior change. The factors associated with transition from pre-contemplation to contemplation were consciousness raising and self efficacy; regarding those from contemplation to preparation, cons of the decisional balance and social liberation; regarding those from preparation to action, dramatic relief and counter conditioning; regarding that from action to maintenance, cons of the decisional balance. CONCLUSION: TTM would be applicable to explain the exercise behavior of some residents in a community, which suggested that the programs for improving exercise behavior of residents in a community need to be developed.
Consciousness
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Organothiophosphorus Compounds
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Self Efficacy
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Surveys and Questionnaires
5.New Measurement Method of Wound Healing by Stereoimage Optical Topometer System.
Kyoung Hwan RHO ; Seung Kyu HAN ; Woo Kyung KIM
Journal of the Korean Society of Plastic and Reconstructive Surgeons 2008;35(6):755-758
PURPOSE: In order to determine the amount of wound healing, objective sequential assessments of changes in wound size and depth are essential. Although a variety of measurements for wound healing have been proposed, a gold standard for quantifying day-to-day changes in healing has not been established. We present here a simple and non-invasive wound measurement method that quantitatively and accurately documents changes of the size of a raw surface and the volume of a soft tissue defect using a stereoimage optical topometer(SOT) system. METHODS: Using a 5mm diameter biopsy punch, four circular wounds were created on abdominal area of a diabetic mouse. Photographs were taken using SOT system at baseline, 5th day and 10th postoperative day. The wound margin was traced on a digitalized photo and evaluated the area and the volume of the wound by SOT system. RESULTS: The SOT system calculated a mean wound surface of 15.93+/-0.29mm2 and volume of 827.50+/-88.86 intensity/pixel x area(I/PA) immediately after wounding. On the 5th day after the operation wound surface declined by 10.73mm2 and on the 10th day declined by 5.95mm2. The wound volume also declined from 827.50 I/PA to 161.75 I/PA and 30.50 I/PA on 0, 5th and 10th day, respectively. CONCLUSION: The SOT system described in this study represents a reliable, simple, practical, and non-invasive technique to accurately monitor and evaluate wound healing.
Animals
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Biopsy
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Mice
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Organothiophosphorus Compounds
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Wound Healing
6.A Comprehensive Computer Program for Monitor Unit Calculation and Beam Data Management: Independent Verification of Radiation Treatment Planning Systems.
Hee Jung KIM ; Yang Kyun PARK ; Jong Min PARK ; Chang Heon CHOI ; Jung In KIM ; Sang Won LEE ; Heon Jin OH ; Chunil LIM ; Il Han KIM ; Sung Joon YE
Korean Journal of Medical Physics 2008;19(4):231-240
We developed a user-friendly program to independently verify monitor units (MUs) calculated by radiation treatment planning systems (RTPS), as well as to manage beam database in clinic. The off-axis factor, beam hardening effect, inhomogeneity correction, and the different depth correction were incorporated into the program algorithm to improve the accuracy in calculated MUs. A beam database in the program was supposed to use measured data from routine quality assurance (QA) processes for timely update. To enhance user's convenience, a graphic user interface (GUI) was developed by using Visual Basic for Application. In order to evaluate the accuracy of the program for various treatment conditions, the MU comparisons were made for 213 cases of phantom and for 108 cases of 17 patients treated by 3D conformal radiation therapy. The MUs calculated by the program and calculated by the RTPS showed a fair agreement within +/-3% for the phantom and +/-5% for the patient, except for the cases of extreme inhomogeneity. By using Visual Basic for Application and Microsoft Excel worksheet interface, the program can automatically generate beam data book for clinical reference and the comparison template for the beam data management. The program developed in this study can be used to verify the accuracy of RTPS for various treatment conditions and thus can be used as a tool of routine RTPS QA, as well as independent MU checks. In addition, its beam database management interface can update beam data periodically and thus can be used to monitor multiple beam databases efficiently.
Animals
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Humans
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Mice
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Organothiophosphorus Compounds
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Software
7.effects of antioxidant belaf drug on the activities of rabbits poisoned by a single acute dose of methamidophos
Journal of Practical Medicine 2004;472(2):45-48
16 adult healthy rabbits aged 12 months were divided into 2 groups. All of them were intoxicated acutely by methamidophos and the one used BELAF sulution, the other group was intoxicated by NaCl 0.9% solution. Results showed that a simple dose of methamidophos could reduce the antioxidant capacity, especially with the activity of red blood cell superocid dismutase and the concentration of reducing total antioxidation of rabbit plasma. However, these changes were recovered after 48 hours of the experiments. The recovered effect of BELAF was not manifested fully.
Antioxidants
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Pharmaceutical Preparations
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Rabbits
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Organothiophosphorus Compounds
8.The effects of antioxidant belaf drug on the activities of rabbits poisoned by a single acute dose of methamidophos
Journal of Practical Medicine 2004;472(2):45-48
16 adult healthy rabbits aged 12 months were divided into 2 groups. All of them were intoxicated acutely by methamidophos and the one used BELAF sulution, the other group was intoxicated by NaCl 0.9% solution. Results showed that a simple dose of methamidophos could reduce the antioxidant capacity, especially with the activity of red blood cell superocid dismutase and the concentration of reducing total antioxidation of rabbit plasma. However, these changes were recovered after 48 hours of the experiments. The recovered effect of BELAF was not manifested fully.
Antioxidants
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Pharmaceutical Preparations
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Rabbits
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Organothiophosphorus Compounds
9.Activity of erythrocyte antioxidant enzymes of rabbits during chronic acephate treatment
Journal of Medical Research 2003;24(4):57-62
The influence of Acephate (an organophosphorous pesticide) on some red cell antioxydant enzymes was studied. Acephate of the doses of 20mg and 40mg/kg of body mass/day was administered on rabbit during 30 days continuously. The activity of superoxyde dismutase (SOD), glutathion peroxydase (GP2), glutathion reductase (TAS) in plasma was determined before and after the intoxication. Results showed a reduce of SOD, GR levels in the day 15 and 31 and a reverse to normal level in the day 45, SOD enzyme and GR enzyme levels reduced in day 15 and 31, while GPx activity increased. Total antioxydation was not varied.
Enzymology
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Antioxidants
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Erythrocytes
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Rabbits
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therapy
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Organothiophosphorus Compounds
10.A Case of Dedifferentiated LiposarcomaThat Developed in the Dermis.
Ji Yeon BYUN ; You Won CHOI ; Hae Young CHOI ; Ki Bum MYUNG
Annals of Dermatology 2008;20(4):204-208
Dedifferentiated liposarcoma is a variant of liposarcoma, and this is characterized by the coexistence of well-differentiated liposarcoma with areas of poorly differentiated, non-lipogenic tumor and this is also known to be associated with more aggressive behavior. Dedifferentiated liposarcoma occurs principally in the retroperitoneum or the deep soft tissue of limbs, but it can also occur in subcutaneous locations. We report here on a peculiar case of dedifferentiated liposarcoma that developed in the dermis, which is an exceedingly rare location for this type of tumor. The occurrence of this tumor in the dermis made it easy to surgically remove and monitor for recurrence, and we expect this patient to have a better prognosis than that of a patient with dedifferentiated liposarcoma located in the retroperitoneum or deep soft tissue.
Dermis
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Extremities
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Humans
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Liposarcoma
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Organothiophosphorus Compounds
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Prognosis
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Recurrence
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Skin