• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.433-439
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• 2013

In this study, human head-mimicking phantom was developed for brain disease treatment study using focused ultrasound. Acoustic parameters of skin, skull and brain were investigated through literature investigation and adequate substitutes according to each tissue were suggested. In the case of skin phantom, construction ratio of glycerol-based TMM phantom was controlled to mimic real skin. The suitability of skull substitutes was evaluated through measurement of acoustic parameters. In the case of brain phantom, transparent egg white phantom was used to observe thermal properties of focused ultrasound. Combined human-head-mimicking phantom using each substitutes was fabricated for development of brain disease treatment protocol. Denaturation of brain phantom according to ultrasonic condition was observed for validation.

• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.895-900
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• 2019

Ultrasound is known to be harmless to the human body and is widely used in obstetrics and gynecology to confirm the diagnosis and development status of fetus. Diagnosis Although long - term use of ultrasound may cause changes in body temperature, studies on the uterine temperature changes due to ultrasound have been lacking. The purpose of this study was to investigate the change of temperature according to ultrasonic scanning time using a self - produced uterine model phantom. Ultrasound equipment and a 4MHz convex probe were used to construct the uterine model phantom similar to the human uterus using acrylic and pig uterus, which are tissue equivalents. Three probe type thermometers were installed to measure the inside of the acrylic water tank, the uterus, and the atmospheric temperature. The temperature of the uterine phantom was ascertained by measuring the temperature of the subject for 6 hours, 361 times. In this study, the possibility of human body temperature elevation due to ultrasound could be confirmed and this study will be used as the basic data of ultrasonic heat absorption study.

• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.199-206
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• 2003

Because the MIRD phantom, the representative mathematical phantom was developed for the calculation of internal radiation dose, and simulated by the simplified mathematical equations for rapid computation, the appropriateness of application to external dose calculation and the closeness to real human body should be justified. This study was intended to modify the MIRD phantom according to the comparison of the organ absorbed doses in the two phantoms exposed to monoenergetic broad parallel photon beams of the energy between 0.05 MeV and 10 MeV. The organ absorbed doses of the MIRD phantom and the Zubal yokel phantom were calculated for AP and PA geometries by MCNP4C, general-purpose Monte Carlo code. The MIRD phantom received higher doses than the Zubal phantom for both AP and PA geometries. Effective dose in PA geometry for 0.05 MeV photon beams showed the difference up to 50%. Anatomical axial views of the two phantoms revealed the thinner trunk thickness of the MIRD phantom than that of the Zubal phantom. To find out the optimal thickness of trunk, the difference of effective doses for 0.5 MeV photon beams for various trunk thickness of the MIRD phantom from 20 cm to 36 cm were compared. The optimal thunk thickness, 24 cm and 28 cm for AP and PA geometries, respectively, showed the minimum difference of effective doses between the two phantoms. The trunk model of the MIRD phantom was modified and the organ doses were recalculated using the modified MIRD phantom. The differences of effective dose for AP and PA geometries reduced to 7.3% and the overestimation of organ doses decreased, too. Because MIRD-type phantoms are easier to be adopted in Monte Carlo calculations and to standardize, the modifications of the MIRD phantom allow us to hold the advantage of MIRD-type phantoms over a voxel phantom and alleviate the anatomical difference and consequent disagreement in dose calculation.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.933-939
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• 2019

The purpose of this study is to provide basic clinical data by evaluating images, measuring absorbed dose and effective dose by using high resolution CT and low dose CT by using anthropomorphic chest phantom and glass dosimeter. Tissue dose was measured by inserting a glass dosimeter into the anthropomorphic chest phantom. A 64-slice CT system (SOMATOM Sensation 64, Siemens AG, Forchheim, Germany) and CARE Dose 4D were used, and the parameters of the high resolution CT were 120 kVp, Eff. Scan parameters of mAs 104, scan time 7.93 s, slice 1.0 mm (Acq. 64 × 0.6 mm), convolution kernel (B60f sharp) were used, and low dose CT was 120 kVp, Eff. mAs 15, scan time 7.41 s, slice 3.0 mm (Acq. 64 × 0.6 mm), scan of convolution kernel B50f medium sharp. CTDIvol was measured at 8.01 mGy for high resolution CT and 1.18 mGy for low dose CT. Low dose CT scans showed 85.49% less absorbed dose than high resolution CT scans.

• Journal of IKEEE
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• v.12 no.4
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• pp.185-195
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• 2008

In this paper, PIFA(Planar Inverted F Antenna) which operates in PCS(Personal Communication System) band is designed and characteristics are investigated. Designed PIFA was installed in three types of handsets, folder, bar, slide, and the performance was evaluated. Head and hand phantom were added to make the most similar environment to real condition of mobile phone use, and influences on antenna performance were analyzed. The simulation results confirm radiation patterns are greatly changed and antenna efficiency is decreased by the effect of human body. Performance variation of the mobile handset antenna was observed as changing the angle between mobile handset and head phantom from $0^{\circ}$ to $2^{\circ},\;4^{\circ}$ to confirm the variation caused by the relative position of mobile handset and head phantom. Directivity was decreased gradually as the antenna goes away from head phantom, and showed the trend of increasing efficiency. But in the case of bar type, where the position of antenna is relatively close to head phantom, that trend didn't show. It was confirmed that the shape of handset has a great effect on the performance.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.78-78
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• 2003

목적： 이전에는 손쉽게 구할 수 있는 표준데이터를 가지고 visual human body model을 형성하였다. 주로 팬텀이나, 외국인의 데이터를 가지고 만든 것이기 때문에 우리가 실제 실험에 쓰려면 큰 차이가 있었다. 그래서 본 연구에서는 실제 우리나라 사람 중 동일 인물의 MR와 CT 이미지를 가지고 인체 모델을 만들고자 하였다. 그러기 위해서 먼저 인체의 MR, CT영상에 대한 특징을 분석해야 했고, 이것을 바탕으로 영상 분할(Image Segmentation)을 하였다. 인체 부위에 따라 영상 분할 방법도 그 차이가 있음을 알 수 있었다.

• Journal of Radiation Protection and Research
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• v.26 no.2
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• pp.93-99
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• 2001

Voxel head phantom for overcoming the limitation of mathematical phantom in depleting anatomical details was constructed and example dose calculation for BNCT was performed. The repeated structure algorithm of the general purpose Monte Carlo code, MCNP4B was applied for yokel Monte Carlo calculation. Simple binary yokel phantom and combinatorial geometry phantom composed of two materials were constructed for validating the voxel Monte Carlo calculation system. The tomographic images of VHP man provided by NLM(National Library of Medicine) were segmented and indexed to construct yokel head phantom. Comparison of doses for broad parallel gamma and neutron beams in AP and PA directions showed decrease of brain dose due to the attenuation of neutron in eye balls in case of yokel head phantom. The spherical tumor volume with diameter, 5cm was defined in the center of brain for BNCT dose calculation in which accurate 3 dimensional dose calculation is essential. As a result of BNCT dose calculation for downward neutron beam of 10keV and 40keV, the tumor dose is about doubled when boron concentration ratio between the tumor to the normal tissue is $30{\mu}g/g$ to $3{\mu}g/g$. This study established the voxel Monte Carlo calculation system and suggested the feasibility of precise dose calculation in therapeutic radiology.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.100-100
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• 2002

목적： 인체에 전류를 주입하면 체내 생체조직의 임피던스 분포에 따라서 전류밀도 분포가 결정된다. 이러한 전류밀도 분포를 MRI를 이용하여 고해상도로 얻어내면 인체 내부의 임피던스 영상을 구성할 수 있다. 이는 기존의 전기 임피던스 단층 촬영법이 갖는 여러 한계를 극복할 수 있으며 이로부터 생체의 기능에 대한 다양한 정보를 추출할 수 있게 된다. 본 논문은 3차원 팬텀 내부의 전류밀도 분포를 영상화하고 이것으로부터 인체내부의 임피던스 영상을 얻어내는 실험 결과를 기술한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.534-540
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• 2013

Interest of the hand effect on the electromagnetic wave are internationally increasing with the increase of the use of the mobile phone. IEC TC106(International Electrotechnical Commission, Technical Committee 106) promotes international research exchange program in order to reflect the effect of human hands in the standard assessment method of human exposure dosimetry by the electromagnetic wave of mobile phones. Since current commercialized hand phantom is manufactured by taking into account the average size of westerners and provides only one grip posture, it imposes many restrictions on the accurate SAR measurement. Therefore, the development of proper hand phantom accounting for domestic situation and various grip posture capability is essential in order to analyze the accurate effect of human hand on the exposure estimation. In this paper, a jelly hand phantom suitable for Korean was manufactured with various grip posture capability at 835 MHz and 1,800 MHz bands. Although the tolerances of permittivity and conductivity of the manufactured hand phantom are with ${\pm}10%$ each, it was much less than CTIA(Cellular Telecommunication Industry Association) tolerance of ${\pm}20%$ at both bands. Its 3D CAD(3 Dimensional Computer Aided Design) file which was developed can be utilized for the simulation of human hand effect on SAR measurement of mobile phones. The findings in this study can be utilized for the analysis of human hand effect on SAR measurement of a mobile phone.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.539-540
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• 2006