• YAKHAK HOEJI
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• v.36 no.2
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• pp.129-136
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• 1992

The effects of ginseng saponins, gypsophila saponin, sodium dodecyl sulfate(SDS), and Triton X-100 on membrane $K^+-dependent$ phosphatase activity which is lipid dependent and represents dephosphorylation step of the complete Na+, $K^+-ATPase$ reaction were investigated in this study to elucidate whether the effects of ginseng saponins are due to the detergent action, using sarcolemma enriched preparation isolated from dog ventricle. $Na^+$, $K^+-ATPase$ and $K^+-dependent$ phosphatase activities of cardiac sarcolemma were about $143\;{\mu}mol$ Pi/mg protein/hr and $34\;{\mu}mol$ p-nitrophenol/mg protein/hr, respectively. While ginseng saponins (triol>total>diol) inhibited $K^+-dependent$ phosphatase activity, gypsophila saponin, and low dose of SDS($0.4\;{\mu}g/{\mu}g$ protein), and Triton X-100 ($0.6\;{\mu}g/{\mu}g$ protein) increased the enzyme activity, indicating disruptive effect of detergents on membrane barriers. The activating effect of low doses of Triton X-100 on membrane $K^+-dependent$ phosphatase appeared at concentration decreasing light scattering. However, the inhibitory effect of ginseng saponin appeared before a decrease in light scattering. These results suggest that low concentrations of ginseng saponins inhibit the membrane $K^+-dependent$ phosphatase by interacting directly with enzyme before membrane disruption.

• Journal of radiological science and technology
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• v.11 no.2
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• pp.3-15
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• 1988

When X-rays were projected into a patient, there occured the phenomena such as penetration, absorption and scattering etc. The penetrating rays were recorded on films as X-ray image used for diagnosis but scattered rays caused the radiation hazard both to the patient, specialist and technicians. The soft tissue includes many organs which are sensitive to the radiation and in may occupy $40{\sim}50%$ of body weight. Therefore X-rays should be carefully projected to the patient and it is strongly recommended to analyse the distribution of X-rays, when ever the patient is exposed to X-rays. In this study, the distribution of X-ray according to the thickness, the radiation field and the tube voltages (kVp) in soft tissue, the following results were obtained: 1. Total transmitted rays which kept the step with X-ray tube voltage (kVp) increased in proportion to the increasing of X-ray tube voltage. 2. The scattered ray rate in the total transmitted ray was not significantly found with X-ray tube voltage. 3. The affecting factors of the scattered ray rate in total transmitted ray were shown through the radiation field and the thickness. 4. The dose of scattered ray by the angle was observed more in direction of primary ray ($0^{\circ}$) and back scattering ($160^{\circ}$) than in direction of $90^{\circ}$. 5. The more the distance from phantom to the patient should be less distribution of scattered ray.

• YAKHAK HOEJI
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• v.29 no.2
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• pp.76-89
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• 1985

The effects of ginseng saponin on the activity, phosphorylation, [$^{3}$H] ouabain binding and light scattering (disruption) of purified $Na^{+}$ ,$K^{+}$ -ATPase isolated from the outer medulla of sheep kidney were compared to those of gypsophila saponin, sodium dodecylsulfate (SDS), and Triton X-100 on the same parameters. $Na^{+}$ , $K^{+}$ -ATPase activity, phosphorylation, and [$^{3}H$] ouabain binding were inhibited by ginseng saponin (triol>total>diol), SDS, or Triton X-100, but increased by gypsophila saponin. Low doses of ginseng saponin (3.mu.g saponin/.mu.g protein) decreased phosphorylation sites and ouabain binding site concentration (Bmax) without any change of turnover number and affinity for ouabain binding which were decreased by high dose of ginseng saponin (over 10.mu.g saponin/.mu.g protein), SDS or Triton X-100. On the other hand, gypsophila saponin increased the affinity without any change of Bmax for ouabain binding. Inhibition of $Na^{+}$ ,$K^{+}$ -ATPase activity by ginseng saponin and SDS or Triton X-100 appeared before and after decrease in light scattering, respectively. These data suggest that ginseng saponins (total, diol, triol saponin) inhibit $Na^{+}$ , $K^{+}$ -ATPase activity by specific direct and general detergent action at low and high concentrations, respectively, and this inhibitory action of ginseng sapornin to $Na^{+}$ , $K^{+}$ -ATPase is not general action of all saponins.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.493-499
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• 2016

In this study, C-Arm equipment is being used as we intend to verify the exposure dose on the operator by the scattering rays during the operation of the C-Arm equipment and to provide an effective method of reducing the exposure dose. Exposure dose is less than the Over Tube method utilizes the C-arm equipment Under Tube the scheme, The result showed that the exposure dose on the operator decreased with a thicker shield, and as the operator moved away from the center line. Moreover, as the research time prolongated, the exposure dose increased, and among the three affixed location of the dosimeter, the most exposure dose was measured at gonadal, then followed by chest and thyroid. However, in consideration of the relationship between the operator and the patient, the distance cannot be increased infinitely and the research time cannot be decreased infinitely in order to reduce the exposure dose. Therefore, by changing the thickness of the radiation shield, the exposure dose on the operator was able to be reduced. If you are using a C-Arm equipment discomfort during surgery because the grounds that the procedure is neglected and close to the dose of radiation shielding made can only increase. Because a separate control room cannot be used for the C-Arm equipment due to its characteristic, the exposure dose on the operator needs to be reduced by reinforcing the shield through an appropriate thickness of radiation shield devices, such as apron, etc. during a treatment.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.168-173
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• 2011

This study investigated characteristics of dose distribution at junction field of X-ray and electron beams according to the method for fabricating the insert block on the electron cone. Insert block were fabricated to the divergency cutout block and the straight cutout block. For the 6 MV X-ray and 10 MeV nominal energy of electron beam, we was adjacent to the light field of X-ray and electron beam at a surface of matrix chamber and measured to beam profile of abutted field in the 0, 1, 2, 3 cm measurement depth. As a result, characteristics of dose distribution at junction field, straight block was existent that over dose area exceed the give dose more than 5% and under dose area with a rapid change in dose distribution. However, divergency block had remarkably decreased the over dose area caused by the lateral scattering effects of decrease, and being existed uniformity dose distribution in the junction field. Therefore, divergency block were the benefits of radiation dose delivery, in order to applied the clinical, measurement of electron beams according to the fabrication method of the block should be considered carefully.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.663-669
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• 2017

In diagnostic medical imaging, it is essential to reduce the scattered radiation for the high medical image quality and low patient dose. Therefore, in this study, the influence of the scattered radiation on medical images was analyzed as the tube voltage increases. For this purpose, ANSI chest phantom was used to measure the scattering ratio, and the scattering effect on the image quality was investigated by RMS evaluation, RSD and NPS analysis. It was found that the scattering ratio with increasing x-ray tube voltage gradually increased to 48.8% at 73 kV tube voltage and to 80.1% at 93 kV tube voltage. As a result of RMS analysis for evaluating the image quality, RMS value according to increase of tube voltage was increased, resulting in low image quality. Also, the NPS value at 2.5 lp/mm spatial frequency was increased by 20% when the tube voltage was increased by 93 kV compared to the tube voltage of 73 kV. From this study, it can be seen that the scattering radiation have a significant effect on the image quality according to the increase of x-ray tube voltage. The results of this study can be used as basic data for the improvement of medical imaging quality.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.597-602
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• 2016

Recent clinical field utilizes the aluminium filter in order to reduce the low-energy photons. However, the usage of the filter can cause adverse effect on the image quality because of the scattered dose that is generated by X-ray hardening phenomenon. Further, usage of filter with improper thickness can be a reason of dose creep phenomenon where unnecessary exposure is generated towards the patient. In this study, the author evaluated the RMS and the RSD analysis in order to have a quantitative evaluation for the effect of forward scattering dose by the filter on the image. as a result of the study, the FSR and the RSD was increased together with the increasing of thickness of the filter. In this study the RSD means the standard deviation of the mean value is relatively size. It can be understood that the signal-to-noise ratio decreases when the average value is taken as a signal and the standard deviation is judged as a noise. The signal-to-noise ratio can understanding as index of resolution at image. Based on these findings, it was quantitatively verified that there is a correlation of the image quality with the FSR by using an additional filter. The results, a 2.5 mmAl which is as recommended by NCRP in the tube voltage of 70 kVp or more showed the 14.6% on the RSD when the filter was not in used. these results are considered able to be utilized as basic data for the study about the filter to improve the quality of the image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1132-1137
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• 2020

In order to reduce unnecessary exposure doses generated when mammography is performed using a mammography device, a shielding ratio analysis was performed when a self-made shielding body made of bismuth was applied to the breast opposite to the imaging site. In order to determine the scattering dose of uncompressed breasts during CC and MLO tests when the right and left are compressed, the experiment is divided into when bismuth is not shielded (Not used: NU group) and when shielded (Used: U group). Proceeded. The average dose of the NU group was 9.568μSv, and the average dose of the U group was 1.038μSv. The average measured dose before and after the use of the bismuth shield was reduced by 89.15%. The use of a bismuth shield for mammography can shield scattered radiation and keep exposure to radiation to a minimum.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.283-293
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• 2002

Purpose : A PC based brachytherapy planning system was developed to display dose distributions on simulation images by 2D isodose curve including the dose profiles, dose-volume histogram and 30 dose distributions. Materials and Methods : Brachytherapy dose planning software was developed especially for the Ir-192 source, which had been developed by KAERI as a substitute for the Co-60 source. The dose computation was achieved by searching for a pre-computed dose matrix which was tabulated as a function of radial and axial distance from a source. In the computation process, the effects of the tissue scattering correction factor and anisotropic dose distributions were included. The computed dose distributions were displayed in 2D film image including the profile dose, 3D isodose curves with wire frame forms and dosevolume histogram. Results : The brachytherapy dose plan was initiated by obtaining source positions on the principal plane of the source axis. The dose distributions in tissue were computed on a $200\times200\;(mm^2)$ plane on which the source axis was located at the center of the plane. The point doses along the longitudinal axis of the source were $4.5\~9.0\%$ smaller than those on the radial axis of the plane, due to the anisotropy created by the cylindrical shape of the source. When compared to manual calculation, the point doses showed $1\~5\%$ discrepancies from the benchmarking plan. The 2D dose distributions of different planes were matched to the same administered isodose level in order to analyze the shape of the optimized dose level. The accumulated dose-volume histogram, displayed as a function of the percentage volume of administered minimum dose level, was used to guide the volume analysis. Conclusion : This study evaluated the developed computerized dose planning system of brachytherapy. The dose distribution was displayed on the coronal, sagittal and axial planes with the dose histogram. The accumulated DVH and 3D dose distributions provided by the developed system may be useful tools for dose analysis in comparison with orthogonal dose planning.

• The Journal of Korean Society for Radiation Therapy
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• v.12 no.1
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• pp.112-116
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• 2000

Purpose : The vertex scalp is always tangentially irradiated during total skin electron beam(TSEB) This study was discuss to the dose distribution at the vertex scalp and to evaluate the use of an electron reflector. positioned above the head as a means of improving the dose uniformity. Methods and Materials Vetex dosimetry was performed using ion-chamber and TLD. Measurements were 6 MeV electron beam obtained by placing an acrylic beam speller in the beam line. Studies were performed to investigate the effect of electron scattering on vertex dose when a lead reflector $40{\times}40cm$ in area, was positioned above the phantom. Results : The surface dose at the vertex, in the without of the reflector was found to be less than $37.8\%$ of the skin dose. Use of the lead reflector increased this value to $62.2\%$ for the 6 MeV beam. Conclusion : The vertex may be significantly under-dosed using standard techniques for total skin electron beam. Use of an electron reflector improves the dose uniformity at the vertex and may reduce or eliminate the need for supplemental irradiation.