• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.91-96
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• 2011

Purpose: The aim of study is to expose a more uniform dose depending on the relationship between a body mass index in patients who underwent radiation therapy and an acquired dosimetric information by using a thermoluminescent dosimeter. Materials and Methods: Since 2006 to August 2011 we investigated 28 people who underwent radiation therapy were enrolled in AMC. Each patient was measured on the head, neck, chest, abdomen, pelvis, thigh, knee joint, and ankle joint using the thermoluminescent dosimeter. The measurement value of each points compared with the prescribed center point, abdominal point, and dose measurements of points on which to base the abdomen and the patient's body mass index (BMI) were compared with reference point, abdomen dose. Results: 28 patients on prescribed dose in the abdomen by which the center point, an average dose was $100.6{\pm}5.5%$, and the other seven measuring points with the average maximum difference among the head, neck, chest, pelvic, thigh, knee, and ankle were $92.8{\pm}4.2%$, $97.6{\pm}6.2%$, $96.4{\pm}5.5%$, $102.6{\pm}5.3%$, $103.4{\pm}7.9%$, $95.8{\pm}5.9%$, $96.1{\pm}5.5%$. The relationship of abdominal point dose and the patient's body mass index (BMI) was analyzed a scatter plot, and the result of linear relationship analysis by regression method, the regression of the dose (y) was -1.009 BMI (x) plus 123.3 and coefficient of determination ($R^2$) was represented 0.697. Conclusion: The total body irradiation treatment process was evaluated the dose deviation and then the prescribed dose by which the average abdominal dose was satisfied with $100.6{\pm}5.5%$. Results of the relationship analysis between BMI and dose, if we apply the correction value for each patients, it can be achieved more uniform dose delivery.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.1
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• pp.51-58
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• 2011

Purpose: In this study, we tried to check the usefulness of two Linear Accelerators, Clinac IX and 21EX (Varian, Palo Alto, CA), which are equipped in Ajou Medical Center. From 2008 to 2010, we evaluated the error range of Absolute Dose based on the daily output, which was measured by CHECKMATE$^{TM}$ (Sun Nuclear, Melbourne, FL). Materials and Methods: For Daily Q.A, photon beams of two linear accelerators, 21EX and IX (6 MV and 10 MV, respectively) were measured daily by using CHECKMATE$^{TM}$ just before the treatment began, while the absolute dose was measured biweekly by using water phantom. We analyzed the data of measured values from the daily Q.A and the absolute dose from 2008 to 2010 for 21EX, and from 2009 to 2010 for IX. We utilized Excel 2007 (Microsoft, USA) to evaluate Average, Standard deviation and Confidence level of the data. Furthermore, in order to check the measured values of CHECKMATE$^{TM}$ and the significance of absolute dose, each error value was compared and analyzed. Results: During the observation period, the output of two equipment's absolute dose increased in process of time and in both 6 MV and 10 MV, there was a similar increasing trend. In addition, the error rate of the measured value of CHECKMATE$^{TM}$ and the value of absolute dose were under 0.34, which means that there is a similarity relationship between the two measured values. After checking that the measured value of CHECKMATE$^{TM}$ increased, We measured the absolute dose to adjust that. When the error range was close to 2~3%, the number of changing the output was four for 21EX and three for IX. Conclusion: As a result of measuring and analyzing the daily output changes for two years by using CHECKMATE$^{TM}$, we could find that there is a significance between the output which we should obey during Q.A, and the measured value of absolute dose within the error tolerance of 2~3%. Thus, the use of CHECKMATE$^{TM}$ can be positively considered for more efficient and reliable daily output verification of linear accelerator. It can also be a good standard for other medical centers to understand the trends of linear accelerator and to refer to for the correction of each output.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.359-371
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• 2010

Facial asymmetry has been found with a higher frequency (70~84%) in skeletal class III malocclusion patients. Anticipating the poor prognosis of prosthesis due to malocclusion, occlusal stability must be obtained by orthodontic treatment. Moreover, orthodontic surgery would be needed in some severe cases for better functional and esthetic results. The orthognathic surgery is performed on one jaw or two jaw depending on the results of facial diagnosis. Genioplasty may change the vertical, horizontal, sagittal position of chin by osteotomy or augmentation using implants, also. This case is about a 24 year-old male patient who visited our clinic to solve the facial asymmetry and mandibular prognathism. Skeletal class III malocclusion, maxillary canting and menton deviation to left by 13 mm were detected. Multiple ill-fitting prostheses, unesthetic maxillary anterior prostheses, and several dental caries were found. After pre-operative orthodontic treatment, Le-Fort I osteotomy, sagittal split ramus osteotomy, genioplasty, right mandibular angle augmentation were done for the correction of jaw relation and asymmetry. By diagnostic wax-up after post-operative orthodontic treatment, maxillary full mouth rehabilitation and mandibular posterior restorations were planned out. For better result, clinical crown lengthening procedure was done on #11, 12 and implant was placed on left mandibular first molar area. The patient was satisfied with the final prostheses. Because of his high caries risk, long-term prognosis will depend on the consistent maintenance of oral hygiene and periodic follow-up.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.537-544
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• 2017

Stable carbon isotope ratio of carbon dioxide (${\delta}^{13}C_{CO2}$) is used as an important indicator in the researches for global climate change and carbon capture and sequestration technology. The ${\delta}^{13}C$ value has been usually analyzed with Isotope Ratio Mass Spectrometer (IRMS). Recently, the use of Laser Absorption Spectrometry (LAS) is increasing because of the cost efficiency and field applicability. The purpose of this study was to suggest practical procedures to prepare laboratory reference gases for ${\delta}^{13}C_{CO2}$ analysis using LAS. $CO_2$ gas was adjusted to have the concentrations within the analytical range. Then, the concentration of $CO_2$ was assessed in a lab approved by the Korea Laboratory Accreditation Scheme and the ${\delta}^{13}C_{CO2}$ value was measured by IRMS. When the instrument ran over 12 hours, the ${\delta}^{13}C$ values were drifted up to ${\pm}10$‰ if the concentration of $CO_2$ was shifted up to 1.0% of relative standard deviation. Therefore, periodical investigation of analytical suitability and correction should be conducted. Because ${\delta}^{13}C_{CO2}$ showed the dependency on $CO_2$ concentration, we suggested the equation for calibrating the concentration effect. After calibration, ${\delta}^{13}C_{CO2}$ was well matched with the result of IRMS within ${\pm}0.52$‰.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.739-746
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• 2010

The purposes of this study are 1) to develop an advanced chamber system within ${\pm}10%$ of air velocity at the particulate matter (PM) collection area, 2) to research theoretical characteristics of PM10 and PM2.5 samplers, 3) to assess the performance characteristics of PM10 and PM2.5 samplers through chamber experiments. The total six one-hour experiments were conducted using the cornstarch with an mass median aerodynamic diameter (MMAD) of $20\;{\mu}m$ and an geometric standard deviation of 2.0 at the two different air velocity conditions of 0.67 m/s and 2.15 m/s in the chamber. The aerosol samplers used in the present study are one APM PM10 and one PM2.5 samplers accordance with the US federal reference methods and specially designed three mini-volume aerosol samplers (two for PM10 and one for PM2.5). The overall results indicate that PM10 and PM2.5 mini-volume samplers need correction factors of 0.25 and 0.39 respectively when APM PM samplers considered as reference samplers and there is significant difference between two mini-volume aerosol samplers when a two-way analysis of variance is tested using the measured PM10 mass concentrations. The PM10 and PM2.5 samplers with the cutpoints and slopes (PM10: $10{\pm}0.5\;{\mu}m$ and $1.5{\pm}0.1$, PM2.5: $2.5{\pm}0.2\;{\mu}m$ and $1.3{\pm}0.03$) theoretically collect the ranges of 86~114% and 64~152% considering the cornstarch characteristics used in this research. Furthermore, the calculated mass concentrations of PM samplers are higher than the ideal mass concentrations when the airborne MMADs for the cornstarch used are smaller than the cutpoints of PM samplers and the PM samplers collected less PM in another case. The chamber experiment also showed that PM10 and PM2.5 samplers had the bigger collection ranges of 37~158% and 55~149% than the theocratical calculated mass concentration ranges and the relatively similar mass concentration ranges were measured at the air velocity of 2.15 m/s comparing with the 0.67 m/s.

• The Korean Journal of Nuclear Medicine
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• v.36 no.4
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• pp.271-276
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• 2002

Purpose: To measure reliable glomerular filtration rate by using the representative values of transplanted renal depths, which are measured with ultrasonography. Materials and Methods: We included 54 patients (26 men, 28 women), with having both renal scintigraphy and ultrasonography after renal transplantation. We measured GFR with Gates' method using the renal depth measured by ultrasonography, and median and mean ones in each patient. We compared GFR derived from ultrasonography-measured renal depth with GFR derived from median and mean renal depths. The correlation coefficients were obtained among GFR derived from ultrasonography-measured renal depths, median and mean renal depths under linear regression analysis. We determined whether GFR derived from median or mean renal depth could substitute GFR derived from ultrasonography-measured renal depth with Bland-Altman method. We analyze the expected errors of the GFR using representative renal depth in terms of age, sex, weight, height, creatinine value, and body surface. Results: The transplanted renal depths range from 3.20 cm to 5.96 cm. The mean value and standard deviation of renal depths measured by ultrasonography are $4.09{\pm}0.65cm$ in men, and $4.24{\pm}0.78cm$ in women. The median value of renal depths measured by ultrasonography is 4.36 cm in men and 4.14 cm in women. The GFR derived from median renal depth is more consistent with GFR derived from ultrasonography-measured renal depth than GFR derived from mean renal depth. Differences of GFR derived from median and ultrasonography-measured renal depth are not significantly different in the groups classified with creatinine value, age, sex, height, weight and body surface. Conclusion: When median value is adapted as a representative renal depth, we could obtain reliable GFR in transplanted kidney simply.