• Journal of Food Hygiene and Safety
• /
• v.11 no.1
• /
• pp.41-50
• /
• 1996

The yields of solvent fraction of irradiated red ginseng powder were increased in the order of petroleum ether(PE)

• Journal of Biomedical Engineering Research
• /
• v.29 no.3
• /
• pp.231-238
• /
• 2008

Nelder-Mead downhill simplex method (DSM), a kind of deterministic optimization algorithms, has been used extensively for magnetoencephalography(MEG) dipolar source localization problems because it dose not require any functional differentiation. Like many other deterministic algorithms, however, it is very sensitive to the choice of initial positions and it can be easily trapped in local optima when being applied to complex inverse problems with multiple simultaneous sources. In this paper, some modifications have been made to make up for DSM's limitations and improve the accuracy of DSM. First of all, initial point determination method for DSM using magnetic fields on the sensor surface was proposed. Secondly, Univariant-DSM combined DSM with univariant method was proposed. To verify the performance of the proposed method, it was applied to simulated MEG data and practical MEG measurements.

• Korean Journal of Veterinary Research
• /
• v.23 no.1
• /
• pp.9-16
• /
• 1983

The effects of ethanol on Na-K-ATPase activity were investigated with cat kidney homogenate. The results were summarized as follows: 1. Na-K-ATPase activity was inhibited with dose-dependent manner by ethanol of higher concentration than 1%, and showed an estimated $I_{50}$ (the inhibitor concentration to cause 50% inhibition) of 7.5%. 2. Hydrolysis of ATP was linear with the incubation time in the absence and presence of 8% ethanol, whereas it was different with preincubation time in the presence of 15% ethanol. 3. Inhibition of Na-K-ATPase activity by ethanol was not affected by increased enzyme concentration, and showed the reversibility of the inhibitory pattern. 4. Kinetic studies of cationic-substrate activation of Na-K-ATPase showed that ethanol had both properties of classical competitive inhibition for $Mg^{{+}{+}}$ or $K^+ and non-competitive inhibition for ATP or $Na^+$. 5. Arrhenius plot yield two break point at $21^{\circ}$ and $30^{\circ}C$ in the absence of ethanol, whereas showing only one break point at $18^{\circ}C$ in the presence of 8% ethanol. These results suggested that ethanol inhibited Na-K-ATPase activity reversible through a disturbance of microenvironment of lipids associated with the enzyme.

• Clinical and Experimental Pediatrics
• /
• v.45 no.10
• /
• pp.1219-1226
• /
• 2002

Purpose : To assess the clinical characteristics of the 2000-2001 measles outbreak in the Seoul metropolitan area, Korea, the clinical data of measles inpatients were analyzed. Methods : Three hundred and five children diagnosed with measles by clinical manifestation from July, 2000 to February, 2001, in Seoul, Ilsan and Ansan City were grouped according to their age and investigated for clinical manifestations, vaccination history and measles-specific IgM/IgG antibody positivity. Results : Thirty eight point seven percent of the subjects were less than 12 months of age, 27.5 % were 12-47 months of age and 33.8% were 48 months of age or older. There was no significant sexual difference(male : female=1.2 : 1). This epidemic started in June, 2000 and the number of patients increased abruptly in October, peaked in December and finally decreased after February, 2001. It started from the older age group and moved to the younger. Sixty five point two percent had a history of more than 1-dose vaccination and 13.6% of the patients equal or more than 48 months of age had a history of 2-dose vaccination. Primary vaccine failure rate was 59.4%(107/180) and secondary vaccine failure rate was 3.9%(7/180) in 1 dose vaccinees. Sixty one point six percent showed more than one complication and 38.4% had no complication. The most common complication was pneumonia(31.8 %), followed by bronchitis(11.5%) and acute otitis media(4.6%). Vaccination and dose were not related significantly with the occurrence of complications. Conclusion : Compared with previous outbreaks in Korea, clinical features showed no specific change in the 2000-2001 measles epidemic. However, primary vaccine failure rate was so high that the second vaccination at four to six years of age must be emphasized in Korea.

• The Journal of Korean Society for Radiation Therapy
• /
• v.16 no.1
• /
• pp.57-65
• /
• 2004

Introduction : The phantom that includes high density materials such as steel was custom-made to fix lung and bone in order to evaluation inhomogeneity correction at the time of conducting radiation therapy to treat lung cancer. Using this, values resulting from the inhomogeneous correction algorithm are compared on the 2 and 3 dimensional radiation therapy planning systems. Moreover, change in dose calculation was evaluated according to inhomogeneous by comparing with the actual measurement. Materials and Methods : As for the image acquisition, inhomogeneous correction phantom(Pig's vertebra, steel(8.21g/cm3), cork(0.23 g/cm3)) that was custom-made and the CT(Volume zoom, Siemens, Germany) were used. As for the radiation therapy planning system, Marks Plan(2D) and XiO(CMS, USA, 3D) were used. To compare with the measurement value, linear accelerator(CL/1800, Varian, USA) and ion chamber were used. Image, obtained from the CT was used to obtain point dose and dose distribution from the region of interest (ROI) while on the radiation therapy planning device. After measurement was conducted under the same conditions, value on the treatment planning device and measured value were subjected to comparison and analysis. And difference between the resulting for the evaluation on the use (or non-use) of inhomogeneity correction algorithm, and diverse inhomogeneity correction algorithm that is included in the radiation therapy planning device was compared as well. Results : As result of comparing the results of measurement value on the region of interest within the inhomogeneity correction phantom and the value that resulted from the homogeneous and inhomogeneous correction, gained from the therapy planning device, margin of error of the measurement value and inhomogeneous correction value at the location 1 of the lung showed $0.8\%$ on 2D and $0.5\%$ on 3D. Margin of error of the measurement value and inhomogeneous correction value at the location 1 of the steel showed $12\%$ on 2D and $5\%$ on 3D, however, it is possible to see that the value that is not correction and the margin of error of the measurement value stand at $16\%$ and $14\%$, respectively. Moreover, values of the 3D showed lower margin of error compared to 2D. Conclusion : Revision according to the density of tissue must be executed during radiation therapy planning. To ensure a more accurate planning, use of 3D planning system is recommended more so than the 2D Planning system to ensure a more accurate revision on the therapy plan. Moreover, 3D Planning system needs to select and use the most accurate and appropriate inhomogeneous correction algorithm through actual measurement. In addition, comparison and analysis through TLD or film dosimetry are needed.

• Journal of radiological science and technology
• /
• v.30 no.4
• /
• pp.381-389
• /
• 2007

The purpose of this study is investigation of radiation dose in CT scan. Data were collected from various references and organizations. Doses measured by CT scanners of each medical organization were analyzed and they were calculated through the examination protocol. The results are as follows : 1. $CTDI_W$ value per 100mAs measured by Head Phantom was the highest in <4-slice MDCT scanner> of 24.20 mGy. $CTDI_W$ values were significantly different among scanner generations(p < 0.01). 2. $CTDI_W$ value per 100 mAs measured using body phantom was the highest in <4-slice MDCT scanner> of 13.58 mGy and the $CTDI_W$ values were significantly different among scanner generations(p < 0.01). 3. When contrast medium was not used, the highest scanner was <16 slice MDCT> of $818.83\;mGy{\codt}cm$ in exposure dose in brain scan(p < 0.05). When the contrast medium was used, the highest scanner was <4 slice MDCT> and its average was $1,460.77\;mGy{\cdot}cm$(p < 0.1). 4. When the contrast medium was not used, the highest scanner was <16-slice MDCT> of $521.63\;mGy{\cdot}cm$ on average in terms of the exposure dose in chest inspection(p<0.05). when the contrast medium was used, the highest scanner was found in 8 slice MDCT scanner and its average was $1,174.70\;mGy{\cdot}cm$. There was no statistically significant difference among scanners. 5. When the contrast medium was not used, the highest scanner was <16-slice MDCT> and its average was $856.27\;mGy{\cdot}cm$ in exposure dose on the abdomen-pelvis(p<0.05). when the contrast medium was used, the highest scanner was <16-slice MDCT> and its average was $1,720.64\;mGy{\cdot}cm$ on average (p < 0.05). 6. When the contrast medium was not used, the highest scanner was <8-slice MDCT> and its average was $612.07\;mGy{\cdot}cm$ in exposure dose in liver inspection(p < 0.05). when the contrast medium was used, the highest scanner was <8-slice MDCT scanner> and its average was $2,197.93\;mGy{\cdot}cm$ in exposure dose(p < 0.1). seventy six point two percent of medical facilities were in risk of radiation exposure while the number of phase was three to four times in their dose inspection of contrast medium.

• The Journal of Korean Society for Radiation Therapy
• /
• v.25 no.1
• /
• pp.77-85
• /
• 2013

Purpose: The accurate movement of gantry rotation, collimator and correct application of dose rate are very important to approach the successful performance of Volumetric Modulated Arc Therapy (VMAT), because it is tightly interlocked with a complex treatment plan. The interruption and restart of dose delivery, however, are able to occur on treatment by various factors of a treatment machine and treatment plan. If unexpected problems of a treat machine or a patient interrupt the VMAT, the movement of treatment machine for delivering the remaining dose will be restarted at the start point. In this investigation, We would like to know the effect of interruptions and restart regarding dose delivery at VMAT. Materials and Methods: Treatment plans of 10 patients who had been treated at our center were used to measure and compare the dose distribution of each VMAT after converting to a form of digital image and communications in Medicine (DICOM) with treatment planning system (Eclipse V 10.0, Varian, USA). We selected the 6 MV photon energy of Trilogy (Varian, USA) and used OmniPro I'mRT system (V 1.7b, IBA dosimetry, Germany) to analyze the data that were acquired through this measurement with two types of interruptions four times for each case. The door interlock and the beam-off were used to stop and then to restart the dose delivery of VMAT. The gamma index in OmniPro I'mRT system and T-test in Microsoft Excel 2007 were used to evaluate the result of this investigation. Results: The deviations of average gamma index in cases with door interlock, beam-off and without interruption on VMAT are 0.141, 0.128 and 0.1. The standard deviations of acquired gamma values are 0.099, 0.091, 0.071 and The maximum gamma value in each case is 0.413, 0.379, 0.286, respectively. This analysis has a 95-percent confidence level and the P-value of T-test is under 0.05. Gamma pass rate (3%, 3 mm) is acceptable in all of measurements. Conclusion: As a result, We could make sure that the interruption of this investgation are not enough to seriously affect dose delivery of VMAT by analyzing the measured data. But this investigation did not reflect all cases about interruptions and errors regarding the movement of a gantry rotation, collimator and patient So, We should continuously maintain a treatment machine and program to deliver the accurate dose when we perform the VMAT for the many kinds of cancer patients.

• Progress in Medical Physics
• /
• v.23 no.4
• /
• pp.219-228
• /
• 2012

The tangential breast intensity modulated radiotherapy (T-B IMRT) technique, which uses the same tangential fields as conventional 3-dimensional conformal radiotherapy (3D-CRT) plans with physical wedges, was analyzed in terms of the calculated dose distribution feature and dosimetric accuracy of beam delivery during treatment. T-B IMRT plans were prepared for 15 patients with breast cancer who were already treated with conventional 3D-CRT. The homogeneity of the dose distribution to the target volume was improved, and the dose delivered to the normal tissues and critical organs was reduced compared with that in 3D-CRT plans. Quality assurance (QA) plans with the appropriate phantoms were used to analyze the dosimetric accuracy of T-B IMRT. An ionization chamber placed at the hole of an acrylic cylindrical phantom was used for the point dose measurement, and the mean error from the calculated dose was $0.7{\pm}1.4%$. The accuracy of the dose distribution was verified with a 2D diode detector array, and the mean pass rate calculated from the gamma evaluation was $97.3{\pm}2.9%$. We confirmed the advantages of a T-B IMRT in the dose distribution and verified the dosimetric accuracy from the QA performance which should still be regarded as an important process even in the simple technique as T-B IMRT in order to maintain a good quality.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.15 no.2
• /
• pp.83-87
• /
• 2011

Purpose: Recently in diagnostics area PET/CT is using a variety of areas including oncology, as well as in cardiology, neurology, etc. While increasing in the importance of PET/CT, there are various researches in the image quality related to reconstruction method. We compared and tested Iterative 2D Reconstruction Method with True X Reconstruction method by Siemens through phantom experiment, so we can see increasing of clinical usefulness of PET/CT. Materials and Methods: We measured contrast ratio and FWHM due to evaluating images on dose and experiment using Biograph 40 True Point PET/CT (Siemens, Germany). Getting a result of contrast ratio and FWHM, we used NEMA IEC PET body phantom (Data Spectrum Corp.) and capillary tube. We used the current TrueX and the previous Iterative 2D algorithm for all images which have 10 minutes long. Also, a clinical suitability of parameter for Iterative 2D and a recommended parameter by Siemens for True X are applied to the experiment. Results: We tested FWHM using capillary tube. As a result, TrueX was less than Iterative 2D. Also, the differences of FWHM get bigger in low dose. On the other hand, we tested contrasts ratio using NEMA IEC PET body phantom. As a result, TrueX was better aspect than Iterative 2D. However, there was no difference in dose. Conclusion: In this experiment, TrueX get higher results of contrast ratio and spatial resolution than Itertive 2D through experiment. Also, in the reconstruction result through TrueX, TrueX had better aspect of resolution than Iterative 2D in low dose. However, contrast ratio had no specific difference. In other words, TrueX reconstruction method in PET/CT had higher clinical value in use because TrueX can reduce exposure of patient and had a better quality of screen.

• Radiation Oncology Journal
• /
• v.7 no.1
• /
• pp.59-70
• /
• 1989

Cervix cancer is the most common female cancer in Korea. In spite of their relatively local invasive tendency, still $44\%$ of patient will develop recurrent cancer. This result suggests that more aggressive local treatment may increase the cure rate but increased complication risk also cannot be avoidable. Various institutions proposed different treatment regimen, but recommended dose were about 4500 cGy for whole pelvis and 8000 cGy at point A, even though they agreed that those doses may not be satisfactory for control of bulky disease. 96 cases of invasive cervical cancer, treated with postoperative or primary radiation therapy were analyzed to determine the complication rate and prognostic factor in our treatment regimen Which is $5500\~1000 CGy$ higher than Other institution. Mean follow up duration was 21 months. Symptomatic patients including mild but persistent abdominal discomfort was $46\%$, but only 1 patient $(1\%)$ had operative treatment because of incomplete obstruction of small bowel. Most symptoms appeared within 12 months and most common complaints were frequent bowel movement. Barium enema and sigmoidoscopy were performed for persistent symptomatic patients. Only one patient had abnormal finding in barium enema which showed inefficiency of this method for detecting bowel complication. Patient's age, total tumor dose, total TDF, rectal dose were not significant risk factors for complication, but boost dose, previous history of operation had some relationship with complication risk. Even though dose of point A and rectum is $500\~1,000cGy$ higher than other institution, such a low rate of severe complications may suggest that fear of complications should not be overestimated than cure rate and the possibility of more aggressive treatment for better local control should not be underestimated.