• Radiation Oncology Journal
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• v.35 no.1
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• pp.78-89
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• 2017

Purpose: To determine the optimal radiotherapy technique for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), we compared the dosimetric parameters and the risk of solid secondary cancer from scattered doses among anterior-posterior/ posterior-anterior parallel-opposed fields (AP/PA), anterior, posterior, right, and left lateral fields (4_field), 3-dimensional conformal radiotherapy (3D-CRT) using noncoplanar beams, and intensity-modulated radiotherapy composed of 7 coplanar beams (IMRT_co) and 7 coplanar and noncoplanar beams (IMRT_non). Materials and Methods: We retrospectively generated 5 planning techniques for 5 patients with gastric MALToma. Homogeneity index (HI), conformity index (CI), and mean doses of the kidney and liver were calculated from the dose-volume histograms. Applied the Biological Effects of Ionizing Radiation VII report to scattered doses, the lifetime attributable risk (LAR) was calculated to estimate the risk of solid secondary cancer. Results: The best value of CI was obtained with IMRT, although the HI varied among patients. The mean kidney dose was the highest with AP/PA, followed by 4_field, 3D-CRT, IMRT_co, and IMRT_non. On the other hand, the mean liver dose was the highest with 4_field and the lowest with AP/PA. Compared with 4_field, the LAR for 3D-CRT decreased except the lungs, and the LAR for IMRT_co and IMRT_non increased except the lungs. However, the absolute differences were much lower than <1%. Conclusion: Tailored RT techniques seem to be beneficial because it could achieve adjacent organ sparing with very small and clinically irrelevant increase of secondary solid cancer risk compared to the conventional techniques.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.55-62
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• 2007

Purpose: Digital medical image commenced with an introduction of PACS has become more popular today in the radiation diagnosis and medical treatment and made great progress, in particular, for medical testing field, whereas it has made slow progress for radiation therapy area. In order to accommodate the current trend of digital from analog, a spherical type mechanical check device (SMCD) that is form of spherical differing from the existing form of flat or cube has been designed and tested its practicability to replace the part in mechanical check with digital image from QA operation. Materials and Methods: If the distance maintains constant between source(target) and image detector with constant distance to the center of spherical type mechanical check device(SMCD), the size will be shown as a constant image at all times regardless of its direction exposed. For the test, two accurate hemispheres are made and put together which results in a sphere of the equilateral circle. Results: It enables a variety of implementation of the existing mechanical check using digital image as follows: congruity level of radiation field and light field, size accuracy of radiation field and collimation field, gantry rotation isocenter check, collimation rotation isocenter check, room laser accuracy check, collimation rotation angle check, couch rotation angle check, and more. Conclusion: It has proved its practicability in checking isocenter congruity level as real time at the time of simultaneous rotation between gantry and couch that is applied to the non-coplanar field, which had been hard to apply as a device formed of existing flat or cube.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.9-16
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• 2018

Purpose : Brain Stereotactic Radiosurgery can treat non-invasive diseases with high rates of complications due to surgical operations. However, brain stereotactic radiosurgery may be accompanied by radiation induced side effects such as fractionation radiation therapy because it uses radiation. The effects of Coplanar Volumetric Modulated Arc Therapy(C-VMAT) and Non-Coplanar Volumetric Modulated Arc Therapy(NC-VMAT) on surrounding normal tissues were analyzed in order to reduce the side effects caused fractionation radiation therapy such as head and neck. But, brain stereotactic radiosurgery these contents were not analyzed. In this study, we evaluated the usefulness of NC-VMAT by comparing and analyzing C-VMAT and NC-VMAT in patients who underwent brain stereotactic radiosurgery. Methods and materials : With C-VMAT and NC-VMAT, 13 treatment plans for brain stereotactic radiosurgery were established. The Planning Target Volume ranged from a minimum of 0.78 cc to a maximum of 12.26 cc, Prescription doses were prescribed between 15 and 24 Gy. Treatment machine was TrueBeam STx (Varian Medical Systems, USA). The energy used in the treatment plan was 6 MV Flattening Filter Free (6FFF) X-ray. The C-VMAT treatment plan used a half 2 arc or full 2 arc treatment plan, and the NC-VMAT treatment plan used 3 to 7 Arc 40 to 190 degrees. The angle of the couch was planned to be 3-7 angles. Results : The mean value of the maximum dose was $105.1{\pm}1.37%$ in C-VMAT and $105.8{\pm}1.71%$ in NC-VMAT. Conformity index of C-VMAT was $1.08{\pm}0.08$ and homogeneity index was $1.03{\pm}0.01$. Conformity index of NC-VMAT was $1.17{\pm}0.1$ and homogeneity index was $1.04{\pm}0.01$. $V_2$, $V_8$, $V_{12}$, $V_{18}$, $V_{24}$ of the brain were $176{\pm}149.36cc$, $31.50{\pm}25.03cc$, $16.53{\pm}12.63cc$, $8.60{\pm}6.87cc$ and $4.03{\pm}3.43cc$ in the C-VMAT and $135.55{\pm}115.93cc$, $24.34{\pm}17.68cc$, $14.74{\pm}10.97cc$, $8.55{\pm}6.79cc$, $4.23{\pm}3.48cc$. Conclusions : The maximum dose, conformity index, and homogeneity index showed no significant difference between C-VMAT and NC-VMAT. $V_2$ to $V_{18}$ of the brain showed a difference of at least 0.5 % to 48 %. $V_{19}$ to $V_{24}$ of the brain showed a difference of at least 0.4 % to 4.8 %. When we compare the mean value of $V_{12}$ that Radione-crosis begins to generate, NC-VMAT has about 12.2 % less amount than C-VMAT. These results suggest that if NC-VMAT is used, the volume of $V_2$ to $V_{18}$ can be reduced, which can reduce Radionecrosis.

• Journal of the Optical Society of Korea
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• v.2 no.2
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• pp.58-63
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• 1998

Cross-talk effects in high-density volume holographic interconnections are investigated using perturbative iteration method of the integral form of Maxwell's wave equation. In this method, the paraxial approximation and negligence of backward scattering introduced in conventional coupled mode theory is not assumed. Interaction geometries consisting of non-coplanar light waves and multiple index gratings are studied. Arbitrary light polarization is considered. Systematic analysis of cross-talk effects due to multiple index gratings is performed in increasing level of diffraction orders corresponding to successive iterations. Some numerical examples are given for first and third order diffraction.

• Journal of the Optical Society of Korea
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• v.1 no.2
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• pp.67-73
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• 1997

Light wave diffraction from multiple superposed volume gratings is inestigated using a perturbative iteration method of the integral equation of Maxwell's wave equation. The host material and index gratings are anisotropic and non-coplanar multiple volume gratings are considered. In this method, the paraxial approximation and lack of backward scattering in conventional coupled mode theory are not assumed. Systematic analysis of anisotropic wave diffraction due to multiple noncoplanar volume index gratings is performed in increasing level of diffraction orders corresponding to successive iterations.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.42-50
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• 2006

Co-Fe-Al-O nano-granular thin films with high electrical resistivity, fabricated by radio frequency magnetron sputtering under an $Ar+O_2$ atmosphere, are found to show good soft magnetic properties in the GHz frequency range. The real part value of the relative permeability is 260 at low frequencies and this value is maintained up to the GHz frequency range. A non-integrated type noise filter on a coplanar waveguide transmission line is demonstrated by using the Co-Fe-Al-O nano-granular thin film with the dimensions of $4\;mm(l){\times}4\;mm(w){\times}0.1\;{\mu}m(t)$. The insertion loss is very low being less than 0.3 dB and this low value is maintained up to 2 GHz. At a ferromagnetic resonance frequency of 3.3 GHz, the degree of noise suppression is measured to be 3 dB. This level of noise attenuation is small for real applications, but there is much room for further improvement by increasing the magnetic volume and integrating the magnetic thin film into the CPW transmission line.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3727-3732
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• 2013

The interaction between metalloporphyrins and diazine tautomers was investigated using quantum chemistry method. The results showed that the metal atom in the metalloporphyrin was not coplanar with porphin ring, and zinc porphyrin has the most extent of its non-coplanar nature. The most stable complex in nine complexes was iron porphyrin. NBO analysis indicated that the interaction between the lone pair of electrons on the nitrogen atom and the unoccupied lone pair orbital of metal contributes significantly to the stability of the complexes. Through the conceptual DFT parameter and Fukui dual descriptor, the thermodynamic stability and reactivity of complexes were analyzed. The density difference function (DDF) analyzes were performed to explore the rearrangement of electronic density after the coordination interaction. NICS calculation indicated that metalloporphyrin aromaticity was reduced after the coordination interaction, and aromaticity of diazine tautomer was increased along direction vector of the coordination interaction force.

• Journal of Information Display
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• v.8 no.3
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• pp.29-33
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• 2007

The temporal dark image sticking phenomena are examined and compared for the two different electrode structures such as the face-to-face and coplanar sustain electrode structure. To compare the temporal dark image sticking phenomena for both structures, the differences in the infrared emission profile, luminance, and perceived luminance of the image sticking cells and the non image sticking cells were measured. It is observed that the temporal dark image sticking is mitigated for the face-to-face structure. The mitigation of the temporal dark image sticking for the face-to-face structure is due to the slight increase in the panel temperature induced by the ITO-less electrode structure.

• Structural Engineering and Mechanics
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• v.34 no.3
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• pp.377-390
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• 2010

This paper studies fracture initiation direction of two parallel non-coplanar cracks of equal length. Using the dislocation pile-up modelling, singular integral equations for two parallel cracks subjected to mixed-mode loading are derived and the crack-tip field including singular and non-singular terms is obtained. The kinking angle is determined by using the maximum hoop stress criterion, or the ${\sigma}_{\theta}$-criterion. Results are presented for simple uniaxial tension and biaxial loading. The biaxiality ratio has a noticeable influence on crack growth direction. For the case of biaxial tension, when neglecting the T-stress the crack branching angle is overestimated for small crack inclination angles relative to the largest applied principal stress direction, and underestimated for large crack inclination angles.

• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.214-223
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• 2013

This paper proposes a theoretical analysis of hidden device detection and a design of multiband circular polarization patch array antenna for non-linear junction detector system application. A good axial ratio of circular polarization patch antenna is realized by a new approach that employs inclined slots, two rectangular grooves and a truncated ground for the conventional antenna. A good axial ratio of the 1.5 dB lower is measured by having an asymmetric gap distance between the ground planes of the coplanar waveguide feeding structure. The common ground plane of the linear array has an optimum trapezoidal slot array to reduce the mutual coupling without increasing the distance between the radiators. The higher gain of about 1 dBi is realized by using the novel common ground structure. The measured return loss, gain, and axial ratio of the proposed single radiator, as well as the proposed array antennas, showed a good agreement with the simulated results.