• Progress in Medical Physics
• /
• v.26 no.3
• /
• pp.119-126
• /
• 2015

The purpose of this study is to analyze motion-induced dose error generated by each tumor motion parameters of irregular tumor motion in helical tomotherapy. To understand the effect of the irregular tumor motion, a simple analytical model was simulated. Moving cases that has tumor motion were divided into a slightly irregular tumor motion case, a large irregular tumor motion case and a patient case. The slightly irregular tumor motion case was simulated with a variability of 10% in the tumor motion parameters of amplitude (amplitude case), period (period case), and baseline (baseline case), while the large irregular tumor motion case was simulated with a variability of 40%. In the phase case, the initial phase of the tumor motion was divided into end inhale, mid exhale, end exhale, and mid inhale; the simulated dose profiles for each case were compared. The patient case was also investigated to verify the motion-induced dose error in 'clinical-like' conditions. According to the simulation process, the dose profile was calculated. The moving case was compared with the static case that has no tumor motion. In the amplitude, period, baseline cases, the results show that the motion-induced dose error in the large irregular tumor motion case was larger than that in the slightly irregular tumor motion case or regular tumor motion case. Because the offset effect was inversely proportion to irregularity of tumor motion, offset effect was smaller in the large irregular tumor motion case than the slightly irregular tumor motion case or regular tumor motion case. In the phase case, the larger dose discrepancy was observed in the irregular tumor motion case than regular tumor motion case. A larger motion-induced dose error was also observed in the patient case than in the regular tumor motion case. This study analyzed motion-induced dose error as a function of each tumor motion parameters of irregular tumor motion during helical tomotherapy. The analysis showed that variability control of irregular tumor motion is important. We believe that the variability of irregular tumor motion can be reduced by using abdominal compression and respiratory training.

• Korean Journal of Acupuncture
• /
• v.30 no.4
• /
• pp.252-263
• /
• 2013

Objectives : Skin color deformation by cupping has been widely used as a diagnostic parameter in Traditional Korean Medicine(TKM). Skin color deformation such as ecchymoses and purpura is induced by local vacuum in a suction cup. Since existing studies have relied on a visual diagnostic method, there is a need to use the quantitative measurement method. Methods : We conducted an analysis of cross-polarization photographic images to assess the changes in skin color deformation. The skin color variation was analyzed using $L^*a^*b^*$ space and the skin erythema index(E.I.). The meridian theory in TKM indicates that the condition of primary internal organs is closely related to the skin color deformation at special acupoints. Before conducting these studies, it is necessary to evaluate whether or not skin color deformation is influenced by muscle condition. Hence, we applied cupping at BL13, BL15, BL18, BL20 and BL23 at Bladder Meridian(BL) and measured blood lactate at every acupoint. Results : We confirmed the high system measurement accuracy, and observed the diverse skin color deformations. Moreover, we confirmed that the $L^*$, $a^*$ and E.I. had not changed after 40 minutes(p>0.05). The distribution of blood lactate levels at each part was observed differently. Blood lactate level and skin color deformation at each part was independent of each other. Conclusions : The negative pressure produced by the suction cup induces a reduction in the volumetric fraction of melanosomes and subsequent reduction in epidermal thickness. The relationship between variations of tissue and skin properties and skin color deformation degree must be investigated prior to considering the relationship between internal organ dysfunction and skin color deformation.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.1
• /
• pp.13-17
• /
• 2010

Purpose: Partial volume effect (PVE) is the phenomenon to lower the accuracy of image due to low estimate, which is to occur from PET/CT 3D image acquisition. The more resolution is declined and the lesion is small, the more it causes a big error. So that it can influence the test result. Studied the optimum image reconstruction method by using variation of parameter, which can influence the PVE. Materials and Methods: It acquires the image in each size spheres which is injected $^{18}F$-FDG to hot site and background in the ratio 4:1 for 10 minutes by using NEMA 2001 IEC phantom in GE Discovey STE 16. The iterative reconstruction is used and gives variety to iteration 2-50 times, subset number 1-56. The analysis's fixed region of interest in detail part of image and compute % difference and signal to noise ratio (SNR) using $SUV_{max}$. Results: It's measured that $SUV_{max}$ of 10 mm spheres, which is changed subset number to 2, 5, 8, 20, 56 in fixed iteration to times, SNR is indicated 0.19, 0.30, 0.40, 0.48, 0.45. As well as each sphere's of total SNR is measured 2.73, 3.38, 3.64, 3.63, 3.38. Conclusion: In iteration 6th to 20th, it indicates similar value in % difference and SNR ($3.47{\pm}0.09$). Over 20th, it increases the phenomenon, which is placed low value on $SUV_{max}$ through the influence of noise. In addition, the identical iteration, it indicates that SNR is high value in 8th to 20th in variation of subset number. Therefore, to reduce partial volume effect of small lesion, it can be declined the partial volume effect in iteration 6 times, subset number 8~20 times, considering reconstruction time.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.16 no.3
• /
• pp.147-154
• /
• 2011

Decision making in Environmental Impact Assessment (EIA) and Consultation on the Coastal Area Utilization (CCAU) is footing on the survey reports, thus requires concrete and accurate information on the natural habitats. In spite of the importance of reporting the ecological quality and status of habitats, the accumulated knowledge and recent techniques in ecology such as the use of investigated cases and indicators/indices have not been utilized in evaluation processes. Even the EIA report does not contain sufficient information required in a decision making process for conservation and development. In addition, for CCAU, sampling efforts were so limited that only two or a few stations were set in most study cases. This hampers transferring key ecological information to both specialist review and decision making processes. Hence, setting the effective number of sampling stations can be said as a prior step for better assessment. We introduced a few statistical techniques to determine the number of sampling stations in macrobenthos surveys. However, the application of the techniques requires a preliminary study that cannot be performed under the current assessment frame. An analysis of the spatial configuration of sampling stations from 19 previous studies was carried out as an alternative approach, based on the assumption that those configurations reported in scientific journal contribute to successful understanding of the ecological phenomena. The distance between stations and number of sampling stations in a $4{\times}4$ km unit area were calculated, and the medians of each parameter were 2.3 km, and 3, respectively. For each study, approximated survey area (ASA, $km^2$) was obtained by using the number of sampling stations in a unit area (NSSU) and total number of sampling stations (TNSS). To predict either appropriate ASA or NSSU/TNSS, we found and suggested statistically significant functional relationship among ASA, survey purpose and NSSU. This empirical approach will contribute to increasing sampling effort in a field survey and communicating with reasonable data and information in EIA and CCAU.

• Journal of the Korean Society of Radiology
• /
• v.14 no.5
• /
• pp.603-612
• /
• 2020

This study has a purpose to look into the effect of the relationship between the Tube current (mA) and SOD(Source to Object Distance), which is a parameter of lower limb angiography examination, and the dilution rate of the contrast medium concentration (300, 320, 350) on the image. To that end, using 3 mm vessel model water phantom, a vessel model custom made in the size of peripheral vessel diameter, this study measured relationships between change of parameters, such as tube current (mA), SOD and varying concentrations (300, 320, 350) of contrast medium dilution into SNR and CNR values while analyzing the coefficients of variance(cv<10). The software used to measure SNR and CNR values was Image J 1.50i from NIH (National Institutes of Health, USA). MPV (mean pixel value) and SD (standard deviation) were used after verifying numerically the image signal for region of interest (ROI) and background on phantom from the DICOM (digital imaging and communications in medicine) 3.0 file transmitted to PACS. As to contrast medium dilution by the change of tube current, when 146 mA and 102 mA were compared, For both SNR and CNR, the coefficient of variation value was less than 10 until the section of CM: N/S dilution (100% ~ 30% : 70%) but CM: N/S dilution rate (20%: 80% ~ 10% : 90%) the coefficient of variation was 10 or more. As to contrast medium dilution by concentration for SOD change, when SOD's (32.5 cm and 22.5 cm) were compared,For both SNR and CNR, the coefficient of variation value was less than 10 until the section of CM: N/S dilution (100% ~ 30% : 70%) but CM: N/S dilution rate (20%: 80% ~ 10% : 90%) the coefficient of variation was 10 or more. As to contrast medium dilution by concentration for SOD change, when SOD's (32.5 cm and 12.5 cm) were compared,For both SNR and CNR, the coefficient of variation value was less than 10 until the section of CM: N/S dilution (100% ~ 30% : 70%) but CM: N/S dilution rate (20%: 80% ~ 10% : 90%) the coefficient of variation was 10 or more. As a result, set a low tube current value in other tests or procedures including peripheral angiography of the lower extremities in the intervention, and make the table as close as possible to the image receiver, and adjust the contrast agent concentration (300) to CM: N/S dilution (30%: 70%). ) Is suggested as the most efficient way to obtain images with an appropriate concentration while simultaneously reducing the burden on the kidney and the burden on exposure.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.5
• /
• pp.19-32
• /
• 2007

In Korea, there have been various methods of estimating groundwater recharge which generally can be subdivided into three types: baseflow separation method by means of groundwater recession curve, water budget analysis based on lumped conceptual model in watershed, and water table fluctuation method (WTF) by using the data from groundwater monitoring wells. However, groundwater recharge rate shows the spatial-temporal variability due to climatic condition, land use and hydrogeological heterogeneity, so these methods have various limits to deal with these characteristics. To overcome these limitations, we present a new method of estimating recharge based on water balance components from the SWAT-MODFLOW which is an integrated surface-ground water model. Groundwater levels in the interest area close to the stream have dynamics similar to stream flow, whereas levels further upslope respond to precipitation with a delay. As these behaviours are related to the physical process of recharge, it is needed to account for the time delay in aquifer recharge once the water exits the soil profile to represent these features. In SWAT, a single linear reservoir storage module with an exponential decay weighting function is used to compute the recharge from soil to aquifer on a given day. However, this module has some limitations expressing recharge variation when the delay time is too long and transient recharge trend does not match to the groundwater table time series, the multi-reservoir storage routing module which represents more realistic time delay through vadose zone is newly suggested in this study. In this module, the parameter related to the delay time should be optimized by checking the correlation between simulated recharge and observed groundwater levels. The final step of this procedure is to compare simulated groundwater table with observed one as well as to compare simulated watershed runoff with observed one. This method is applied to Mihocheon watershed in Korea for the purpose of testing the procedure of proper estimation of spatio-temporal groundwater recharge distribution. As the newly suggested method of estimating recharge has the advantages of effectiveness of watershed model as well as the accuracy of WTF method, the estimated daily recharge rate would be an advanced quantity reflecting the heterogeneity of hydrogeology, climatic condition, land use as well as physical behaviour of water in soil layers and aquifers.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.12
• /
• pp.897-905
• /
• 2013

In this study, sorption coefficients (${\log}K_{OC}$, n) for the binding of phenanthrene (PHE) to soil humins, insoluble fraction of soil humc substances (HS), were determined and relationship between the sorption coefficients and structural characteristics of the soil humins were investigated. The soil humins used in the present study were isolated from 7 different soils including 5 domestic soils, an IHSS standard and a peat soil, and characterized by elemental analysis and CPMAS $^{13}C$ NMR method. $^{13}C$ NMR spectral features indicate that the soil humins are mainly made up of aliphatic carbons (57.1~72.3% in total carbon) with high alkyl-C moiety, and the alkyl-C contents ($C_{Al-H,C}$, %) was in order of granite soil Hu (26~42%) > volcanic ash soil, HL Hu (23.9%) > Peat Hu (14.0%). The results of correlation study show that a positive relationship ($r^2$ = 0.77, p < 0.05) between organic carbon normalized-sorption coefficients ($K_{OC}$, mL/g) and alkyl-C contents($C_{Al-H,C}$, %), while negative relationship ($r^2$ = (-)0.74, p < 0.05) between Freundlich sorption parameter (n) and H,C-substituted aromatic carbon contents ($C_{Ar-H,C}$, %). The magnitude of $K_{OC}$ values are also negatively well correlated with polarity index (e.g., PI, N + O)/C) ($r^2$ = (-)0.74, p < 0.1). These results suggest that the binding capacity (e.g., $K_{OC}$) for PHE is increased in soil humin molecules having high contents of alkyl-C or lower polarity, and nonlinear sorption for PHE increased as the H,C-substituted aromatic carbon contents ($C_{Ar-H,C}$, %) in the soil humins increased. The PHE sorption characteristics on soil humins are discussed based on the dual reactive mode of sorption model.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.7 no.2
• /
• pp.78-86
• /
• 2002

Abundance, carbon biomass and chlorophyll a concentration of each size-fractionated plankton on the basis of trophical level were investigated in terms of spacial and temporal distribution, and interactions between each biological parameter and environmental factors in Jungmun coastal waters of Jeju Island from July 1999 to June 2000. Heterotrophic picoplankton (HPP) abundance averaged 1.4${\times}$$10^{6}$ cells ${\cdot}$ $ml^{-1}$ at of offshore and 8.3${\times}$$10^{5}$ cells ${\cdot}$ $ml^{-1}$ at inshore, while autotrophic picoplankton (APP) abundance 9.9${\times}$$10^{4}$ cells ${\cdot}$ $ml^{-1}$ at of offshore and 7.1${\times}$$10^{4}$ cells ${\cdot}$ $ml^{-1}$ at inshore. They were more abundant at of offshore than at inshore, and also more abundant than the other areas of Korean waters. On the other hand, heterotrophic and autotrophic nanoplankton (HNP, ANP) were more abundant at inshore than at of offshore. Microplankton (AMP) abundance was affected by diatom (r=0.962, P${\le}$0.001) at inshore and by dinoflagellate (r=0.868, P${\le}$0.001) at of offshore. However correlations between each plankton group in terms of size and trophic level were not significant. Carbon biomass showed as same as the distribution pattern of abundance, but composition percentage of each biomass of plankton group were quite different from that of abundance, representing the highest percentage in ANP. Seasonal fluctuation of chlorophyll a were different according to size class, showing the highest with 0.42 ${\mu}g$CHl-${\alpha}$${\cdot}$$1^{-1}$(57.9%) of APP in March 2000, 1.42 ${\mu}g$CHl-${\alpha}$${\cdot}$$1^{-1}$(74.7%) of ANP in May 2000, and 1.51 ${\mu}g$CHl-${\alpha}$${\cdot}$$1^{-1}$(81.8%) of AMP in July 1999. Correlation between biological parameters and environmental factors by principle component analysis revealed that the first factor as main explanation is the increasing of phosphorus and silica and the increasing of the at both of offshore and inshore. The N:P ratio were 36.4 at inshore and 32.6 at of offshore, showing the lack of phosphorus. Thus we suggest that phosphorus might be a main limiting factor to affect phytoplankton community in the study area.

• Childhood Kidney Diseases
• /
• v.8 no.1
• /
• pp.33-42
• /
• 2004

Purpose : Children with nephrotic syndrome(NS) are under high risk for metabolic bone disease(MBD) as a complication of long-term glucocorticoid therapy. We prospectively evaluated the effect of oral bisphosphonate(alendronate) therapy in children with NS, which has proven efficacy in adult patients with glucocorticoid induced MBD. Methods : Among 58 children with NS, aged 5 to 8 years and haying a disease duration of more than 2 years, 30(51.7%) were enrolled to meet the selection criteria, less than -1.0 Z-scores of lumbar spine bone mineral density(BMD) by dual energy X-ray absorptiometry (DEXA). These 30 children were divided into three groups and each were assigned to receive alendronate, calcitriol, and no-medication, respectively for one year. Lumbar spine BMD was followed up every 6 months and the biochemical indexes were measured before and 1 year after the treatment. There were no significant difference among groups with respect to the average age, the initial BMD, and the cumulative steroid doses. Analysis of the treatment efficacy was done by the % change of BMD and by the changes in Z-scores of lumbar spine BMD. Results : Mean age and disease duration of patients at the initial lumbar spine BMD evaluation was $7.4{\pm}1.7$ years and $2.2{\pm}1.2$ years, respectively. Twenty-three of 30 children(76%) had osteopenia, and seven(23%) had osteoporosis. There was no difference in the biochemical values among the groups, before and 1 year after the treatment(P<0.05). Twenty two children(73.3%) with frequent relapsing or steroid dependant NS had more frequent MBD, compared to the 8 children(26.6%) with infrequent relapsing NS. The one year % changes of BMD were 8.56 in alendronate group, 5.79 in calcitriol group, and 1.9 in no-medication group. The changes in Z-score of lumbar spine BMD increased in the alendronate group and the calcitriol group, but not in the no-medication group. One year % changes of BMD were different among groups(P=0.0002). Significant differences were found between the alendronate and the no-medication group, and between the calcitriol and the no-medication group(P<0.05). There was no difference between the alendronate and the calcitriol group. No serious adverse effect was observed in the alendronate group. Conclusion : Children with NS receiving high dose steroids are under the high risk of BMD and should undergo regular BMD evaluation. Z-score of lumbar spine BMD was a useful parameter in diagnosing low bone mass in children. Alendronate weekly oral therapy was effective and relatively safe in increasing the lumbar spine BMD in children with NS having steroid induced MBD.

• Journal of radiological science and technology
• /
• v.33 no.2
• /
• pp.97-107
• /
• 2010

The objectives of this study is to figure out the unknown image processing methods of commercial CR system. We have implemented the processing curve of each Look up table(LUT) in REGIUS 150 CR system by using virtual digital test pattern method. The characteristic of Dry Imager was measured also. First of all, we have generated the virtual digital test pattern file with binary file editor. This file was used as an input data of CR system (REGIUS 150 CR system, KONICA MINOLTA). The DICOM files which were automatically generated output files by the CR system, were used to figure out the processing curves of each LUT modes (THX, ST, STM, LUM, BONE, LIN). The gradation curves of Dry Imager were also measured to figure out the characteristics of hard copy image. According to the results of each parameters, we identified the characteristics of image processing parameter in CR system. The processing curves which were measured by this proposed method showed the characteristics of CR system. And we found the linearity of Dry Imager in the middle area of processing curves. With these results, we found that the relationships between the curves and each parameters. The G value is related to the slope and the S value is related to the shift in x-axis of processing curves. In conclusion, the image processing method of the each commercial CR systems are different, and they are concealed. This proposed method which uses virtual digital test pattern can measure the characteristics of parameters for the image processing patterns in the CR system. We expect that the proposed method is useful to analogize the image processing means not only for this CR system, but also for the other commercial CR systems.