• Progress in Medical Physics
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• v.17 no.2
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• pp.105-113
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• 2006

This study peformed to confirm the corrected dose In different electron density materials using the superposition/FFT convolution method in radiotherapy Planning system. The experiments of the $K_2HPO_4$ diluted solution for bone substitute, Cork for lung and n-Glucose for soft tissue are very close to effective atomic number of tissue materials. The image data acquisited from the 110 KVp and 130 KVp CT scanner (Siemes, Singo emotions). The electron density was derived from the CT number (H) and adapted to planning system (Xio, CMS) for heterogeneity correction. The heterogeneity tissue phantom used for measurement dose comparison to that of delivered computer planning system. In the results, this investigations showed the CT number is highly affected in photoelectric effect in high Z materials. The electron density in a given energy spectrum showed the relation of first order as a function of H in soft tissue and bone materials, respectively. In our experiments, the ratio of electron density as a function of H was obtained the 0.001026H+1.00 in soft tissue and 0.000304H+1.07 for bone at 130 KVp spectrum and showed 0.000274H+1.10 for bone tissue in low 110 KVp. This experiments of electron density calibrations from CT number used to decide depth and length of photon transportation. The Computed superposition and FFT convolution dose showed very close to measurements within 1.0% discrepancy in homogeneous phantom for 6 and 15 MV X rays, but it showed -5.0% large discrepancy in FFT convolution for bone tissue correction of 6 MV X rays. In this experiments, the evaluated doses showed acceptable discrepancy within -1.2% of average for lung and -2.9% for bone equivalent materials with superposition method in 6 MV X rays. However the FFT convolution method showed more a large discrepancy than superposition in the low electron density medium in 6 and 15 MV X rays. As the CT number depends on energy spectrum of X rays, it should be confirm gradient of function of CT number-electron density regularly.

• Radiation Oncology Journal
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• v.22 no.1
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• pp.64-68
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• 2004

Purpose : To study the feasibility of verifying real-time 2-D dose distribution measurement system with the scintillation screen for the quality assurance. Materials and Methods : The water phantom consisted of a scintillation screen (LANEX fast screen, Kodak, USA) that was axially located in the middle of an acrylic cylinder with a diameter of 25 cm. The charge-coupled device (CCD) camera was attached to the phantom In order to capture the visible light from the scintillation screen. To observe the dose distribution In real time, the intensity of the light from the scintillator was converted to a dosage. The isodose contours of the calculations from RTP and those of the measurements using the scintillation screen were compared for the arc therapy and the Intensity modulated radiation therapy (IMRT). Results : The kernel, expressed as a multiplication of two error functions, was obtained in order to correct the sensitivity of the CCD of the camera and the scintillation screen. When comparing the calculated isodose and measured isodose, a discrepancy of less than 8 mm in the high dose region was observed. Conclusion : Using the 2-D dosimetry system, the relationship between the light and the dosage could be found, and real-time verification of the dose distribution was feasible.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.588-598
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• 2020

Objectives: Human indices were developed to determine returning point of residents and damage restoration after the chemical accident Methods: To determine the returning point of residents after the chemical accident, a new concept, the standard man model was introduced as a human index, in which both H-code and its acute effects were main idea. To evaluate the applicability, a hydrogen fluoride leakage accident in Gumi was applied. The returning point were suggested as the conservative remission period of acute effects among relevant hazard effects and compared with actual returning point. The coverage of each age group were considered with reflecting average daily dose expected for actual residents. In addition, a relief-index as a social-scientific approach was reflected as well to apply the damage restoration Results: Actual returning point of residents in Gumi was 88 days; and that of standard man model suggested was 84 days. The expected amount of exposure at aged 12 or under was at least 2.35 times greater than that of this model, 40s, theoretically. However, their population ratio was less than 1%, so 99% of residents could be applied when the standard man model was applied. The relief-index was as an objective and quantitative methodology to apply the qualitative aspect. Conclusions: Although evaluated as a relatively positive result, there was a limitation such as the number of accident applied to the verification of standard man model. The relief index was also considered, but further research should be carried out to find threshold level for the relief.

• Progress in Medical Physics
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• v.28 no.3
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• pp.106-110
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• 2017

The variable density phantom fabricated with varying the infill values of 3D printer to provide more accurate dose verification of radiation treatments. A total of 20 samples of rectangular shape were fabricated by using the $Finebot^{TM}$ (AnyWorks; Korea) Z420 model ($width{\times}length{\times}height=50mm{\times}50mm{\times}10mm$) varying the infill value from 5% to 100%. The samples were scanned with 1-mm thickness using a Philips Big Bore Brilliance CT Scanner (Philips Medical, Eindhoven, Netherlands). The average Hounsfield Unit (HU) measured by the region of interest (ROI) on the transversal CT images. The average HU and the infill values of the 3D printer measured through the 2D area profile measurement method exhibited a strong linear relationship (adjusted R-square=0.99563) in which the average HU changed from -926.8 to 36.7, while the infill values varied from 5% to 100%. This study showed the feasibility fabricating variable density phantoms using the 3D printer with FDM (Fused Deposition Modeling)-type and PLA (Poly Lactic Acid) materials.

• Journal of Applied Biological Chemistry
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• v.58 no.2
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• pp.183-187
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• 2015

The electron donating ability, elastase inhibitory, procollagen synthesis and Matrix metalloprotease-1 (MMP-1) activities were measured in order to verify the anti-wrinkle properties of extracts from Buplerum falcatum as a functional ingredient for cosmetic products. Electron donating ability and elastase inhibition activities were 80 and 52% at a dose of $1,000{\mu}g/mL$ of B. falcatum 70% ethanol extract. Pro-collagen synthesis was increased with the increase concentration of B. falcatum extract on CCD-986sk in addition to decrease the amount of protein of MMP-1. The results suggested that B. falcatum extract can be used to reduced electron donating ability, elastase, pro-collagen synthesis and MMP-1 activity and is a potential candidate for cosmedical materials.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.107-115
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• 2017

Over the last decade, physiologically based pharmacokinetics (PBPK) application has been extended significantly not only to predicting preclinical/human PK but also to evaluating the drug-drug interaction (DDI) liability at the drug discovery or development stage. Herein, we describe a case study to illustrate the use of PBPK approach in predicting human PK as well as DDI using in silico, in vivo and in vitro derived parameters. This case was composed of five steps such as: simulation, verification, understanding of parameter sensitivity, optimization of the parameter and final evaluation. Caffeine and ciprofloxacin were used as tool compounds to demonstrate the "fit for purpose" application of PBPK modeling and simulation for this study. Compared to caffeine, the PBPK modeling for ciprofloxacin was challenging due to several factors including solubility, permeability, clearance and tissue distribution etc. Therefore, intensive parameter sensitivity analysis (PSA) was conducted to optimize the PBPK model for ciprofloxacin. Overall, the increase in $C_{max}$ of caffeine by ciprofloxacin was not significant. However, the increase in AUC was observed and was proportional to the administered dose of ciprofloxacin. The predicted DDI and PK results were comparable to observed clinical data published in the literatures. This approach would be helpful in identifying potential key factors that could lead to significant impact on PBPK modeling and simulation for challenging compounds.

• International Journal of Contents
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• v.14 no.3
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• pp.39-45
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• 2018

Purpose: Food Allergen Immunotherapy (Oral) is a form of immunotherapy administered to patients who are allergic to foods such as egg, milk, and peanut. The food allergen is orally administered to the patient in an escalating dose for desensitization or tolerance development. The safety and effectiveness of the therapy were assessed using a systematic literature review and meta-analysis. Methods: For a literature search, 8 national databases and a number of international databases including Ovid-MEDLINE, Ovid-EMBASE, and Cochrane Library were used; and 13 articles (all from international databases) were selected. The target of Food Allergen Immunotherapy (Oral) included patients with food allergy, and the intervention was food allergen immunotherapy without limiting the food type. The safety and effectiveness of Food Allergen Immunotherapy (Oral) were assessed by reviewing all the articles reporting on the therapy. The control group received standard therapies including aversion therapy, no treatment, anti-histamine treatment, and placebo. Safety was assessed through the incidence of complication and emergency medication. Effectiveness was assessed based on therapy success rate, symptomatic improvement, and quality of life. Results: Although Food Allergen Immunotherapy (Oral) was shown to have successful desensitization in patients with food allergy, the safety of the technique has not yet reached an acceptable level; the possible reason is due to the high rate of complication and frequency of emergency medication. Also, each study employed varying protocols while relying on a small number of participants and a short monitoring period. Conclusion: The results of assessment suggest that the level of evidence from current literature review is low and further research is necessitated for the verification of the safety and effectiveness of the therapy (Grade of Recommendation: A; Level of Technology: II-b).

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.529-535
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• 2020

Geant4 is compatible with the Windows operating system in C++ language use, enabling interface functions that link DICOM or software. It was simulated to address the basic structure of the simulation using Geant4/Gate code and to specifically verify the density composition and lung cancer process in the human phantom. It was visualized using the Gate Graphic System, i.e. openGL, Ray Tracer: Ray Tracing by Geant4 Tracing, and using Geant4/Gate code, lung cancer is modeled in the human phantom area in 3D, 4D to verify the simulation progress. Therefore, as a large number of new functions are added to the Gate Code, it is easy to implement accurate human structure and moving organs.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.368-372
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• 2016

Background: Methodologies for a series of radiological consequence assessments show a distinctive difference according to the design principles of the original nuclear suppliers and their technical standards to be imposed. This is due to the uncertainties of the accidental source term, radionuclide behavior in the environment, and subsequent radiological dose. Both types of PWR and PHWR are operated in Korea. However, technical standards for evaluating atmospheric dispersion have been enacted based on the U.S. NRC's positions regardless of the reactor types. For this reason, it might cause a controversy between the licensor and licensee of a nuclear power plant. Materials and Methods: It was modelled under the framework of the NRC Regulatory Guide 1.145 for light-water reactors, reflecting the features of heavy-water reactors as specified in the Canadian National Standard and the modelling features in MACCS2, such as atmospheric diffusion coefficient, ground deposition, surface roughness, radioactive plume depletion, and exposure from ground deposition. Results and Discussion: An integrated accident consequence assessment code, ACCESS (Accident Consequence Assessment Code for Evaluating Site Suitability), was developed by taking into account the unique regulatory positions for reactor types under the framework of the current Korean technical standards. Field tracer experiments and hand calculations have been carried out for validation and verification of the models. Conclusion: The modelling approaches of ACCESS and its features are introduced, and its applicative results for a hypothetical accidental scenario are comprehensively discussed. In an applicative study, the predicted results by the light-water reactor assessment model were higher than those by other models in terms of total doses.

• The Korea Journal of Herbology
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• v.29 no.5
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• pp.55-63
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• 2014

Objectives : The purpose of this study was verification of the restoration ability effect of Danggwisusan extract(DG) in wound induced Rat. Methods : It needed to make a scar(around $2{\times}2cm^2$) on the top of the fascia in the back of the rats and then the rats were divided into 4groups(n=6). Control was not treated at all, where as DG was orally medicated DG, Terra was percutaneously applied Terramycin, and DG + Terra was both orally medicated DG and percutaneously applied Terramycin per day for three weeks. Results : 93% or higher cell viability was observed in all tested groups from 1, 10, $100{\mu}g/m{\ell}$ in RAW 264.7cells. The DG decreased NO and cytokine production activity dose dependently. The production of IL-$1{\beta}$, IL-6 and TNF-${\alpha}$ were decreased by 46%, 46% and 40% in DG treated $100{\mu}g/m{\ell}$. The size of wound was significantly decreasing in DG, Terra, DG + Terra. WBC was significantly reduced in DG and DG + Terra. Monocyte was significantly reduced in DG, Terra and DG + Terra. Neutrophil was also reduced in DG, DG + Terra but not meaningless. The mRNA expression of MMP-1 was significantly reduced in Terra, MMP-2 was significantly reduced in DG, Terra, DG + Terra, and MMP-9 was significantly reduced in DG + Terra. Conclusions : According to the results, we thought that DG showed anti-inflammatory activities on the RAW 264.7cells in mouse macrophage and in adult rat wound. Moreover, the progress of recovery was found visually, heamatologically, genetically and histopathologically. In conclusion, it could be thought that DG has effect on the treating of wound.