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Evaluation of Skin Dose and Image Quality on Cone Beam Computed Tomography (콘빔CT 촬영 시 mAs의 변화에 따른 피부선량과 영상 품질에 관한 평가)

  • Ahn, Jong-Ho;Hong, Chae-Seon;Kim, Jin-Man;Jang, Jun-Young
    • The Journal of Korean Society for Radiation Therapy
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    • v.20 no.1
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    • pp.17-23
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    • 2008
  • Purpose: Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. but imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Materials and Methods: Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in seperately H&N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. Results: The results of the measured skin dose are described in here. The skin dose of Head & Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Conclusion: Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low mAs technique.

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Study on characterization of hydrogenated carbon nitride thin films prebared by Plasma-Assisted Chemical Vapor Deposition (RF-PACVD를 이용한 Hydrogenated Carbon Nitride박막의 합성 및 특성에 관한 연구)

  • Lee, Chul-Hwa;Kim, Byoung-Soo;Park, Gu-Bum;Lee, Sang-Hee;Jin, Yoon-Young;Lee, Duck-Chool
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.856-857
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    • 1998
  • Hydrogenated amorphous carbon nitride [a-C:H(N)] films were deposited on pretreated silicon(100) substrate in activated gas phase using. RF plasma-assisted CVD. We measured the FT-IR spectrum to investigate $C{\equiv}N$ stretching mode(nitrile), C-H stretching mode, C-H bending mode, C=C stretching mode C=N(imino) mode, and the EDX to investigate the ratio of N to C(0.25). By the results of FT-IR and EDX spectrum, We confirmed that hydrogenated amorphous carbon nitride films successfully were synthesized by RF-PACVD

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A Study on carbon nitride thin films prepared by RF reactively sputtering (RF 반응성 스퍼터링에 의한 비정질 carbon nitride 박막의 제조에 관한 연구)

  • 이철화;김병수;이상희;진윤영;이덕출;박구범
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.406-408
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    • 1999
  • Amorphous carbon nitride thin films were prepared on pretreated silicon(100) substrate in sputtering graphite target by activated gas phase using RF reactively sputtering. We measured the FT-IR spectrum to identify C=N(nitrile)stretching mode(2200cm$\^$-1/), C-H stretching mode(2800cm$\^$-1/), C-H bending mode, C=C stretching mode C=N(imino) mode(1680cm$\^$-1/ ), and the XPS to investigate chemical structure of surface. By the results of FT-H and XPS spectrum, We confirmed that amorphous carbon nitride films with typel (C(1s): 285.9[eV], N(1s): 398.5[ev]) and type 2(C1s): 287.5[eV, N(1s): 400.2[eV]) successfully were synthesized by RF reactively sputtering

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A comparison study of measured values and subjective experience of mercury thermometer and tympanic thermometer (수은체온계와 고막체온계의 측정치와 측정시 경험에 관한 비교연구)

  • Min Soon
    • The Journal of Korean Academic Society of Nursing Education
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    • v.4 no.1
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    • pp.95-106
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    • 1998
  • This study aims to provide a better nursing service in the dimension of economizing time and human efforts. This is to present some basic knowledge necessary to improving a nursing quality in measuring body temperature by analyzing the contents that the objects experienced at the time of measure with tympanic thermometer and mercury thermometer Subjects of the survey consisted of 71 college students, 47 adult patients and 40 pediatric patients. The results were as follows : 1. The oral temperature by mercury thermometer and tympanic thermometer with oral mode was : $36.83^{\circ}C$ by mercury thermometer and $37.02^{\circ}C$ by tympanic thermometer in college students : it showed an significant difference statistically. 2. Comparsion between oral mode and rectal mode by tympanic thermometer in college students : $37.03^{\circ}C$ by oral mode and $37.55^{\circ}C$ by rectal mode and this defference was significant statistically 3. Comparision between rectal temperature by mercury thermometer and rectal mode of tympanic thermometer : $37.54^{\circ}C$ by mercury thermometer and $37.73^{\circ}C$ by tympanic thermometer, it showed a significant difference statistically. 4. Comparision between oral temperature by mercury thermometer and oral mode of tympanic thermometer of the pediatric patients : $36.51^{\circ}C$ by mercury temperature and $36.94^{\circ}C$ by tympanic thermometer, it showed a significant difference statistically. 5. Comparision between oral body temperature by mercury thermometer and oral mode of tympanic thermometer of the adult patients : $36.56^{\circ}C$ by mercury thermometer and $36.90^{\circ}C$ by tympanic thermometer, it did not show statistically any difference. 6. At the measure by mercury thermometer this data can classified In three main categorise : their feeling to a thermometer, thermometer itself and aspect physical of the clients. It is considered that an subjective experience to tympanic thermometer was more positive.

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An Enhancement of Channel Separability for Stereophonic Signals by Common Mode Rejection Method (동상분 제거에 의한 입체음향의 채널 분리도 개선)

  • Kwon, Ho-Yeol
    • Journal of Industrial Technology
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    • v.18
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    • pp.439-442
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    • 1998
  • In this paper, we firstly suggested C&D (Common mode and Differential mode) model for the representation of a stereophonic signal. Then a measure of stereophonic channel separability is defined as the ratio of differential mode energy to total energy in frequency domain. After that, a new channel separability enhancement scheme is proposed by the control of common mode rejection. Finally, some experimental results are presented in order to verify our scheme.

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Wide-Input Range Dual Mode PWM / Linear Buck Converter with High robustness ESD Protection Circuit

  • Song, Bo-Bae;Koo, Yong-Seo
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.292-300
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    • 2015
  • This paper proposes a high-efficiency, dual-mode PWM / linear buck converter with a wide-input range. The proposed converter was designed with a mode selector that can change the operation between PWM / linear mode by sensing a load current. The proposed converter operates in a linear mode during a light load and in PWM mode during a heavy load condition in order to ensure high efficiency. In addition, the mode selector uses a bit counter and a transmission gate designed to protect from a malfunction due to noise or a time-delay. Also, in conditions between $-40^{\circ}C$ and $140^{\circ}C$, the converter has variations in temperature of $0.5mV/^{\circ}C$ in the PWM mode and of $0.24mV/^{\circ}C$ in the linear mode. Also, to prevent malfunction and breakdown of the IC due to static electricity, the reliability of IC was improved by embedding a self-produced 8 kV-class(Chip level) ESD protection circuit of a P-substrate Triggered SCR type with high robustness characteristics.

Characteristics of Surface Micromachined Capacitive Pressure Sensors for High Temperature Applications (표면 MEMS 기술을 이용한 고온 용량형 압력센서의 특성)

  • Seo, Jeong-Hwan;Noh, Sang-Soo;Kim, Kwang-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.4
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    • pp.317-322
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    • 2010
  • This paper reports the fabrication and characterization of surface micromachined poly 3C-SiC capacitive pressure sensors on silicon wafer operable in touch mode and normal mode for high temperature applications. FEM(finite elements method) simulation has been performed to verify the analytical mode. The sensing capacitor of the capacitive pressure sensor is composed of the upper metal and the poly 3C-SiC layer. Measurements have been performed in a temperature range from $25^{\circ}C$ to $500^{\circ}C$. Fabrication process of designed poly 3C-SiC touch mode capacitive pressure sensor was optimized and would be applicable to capacitive pressure sensors that are required high precision and sensitivity at high pressure and temperature.

Success Factor of m-commerce; A case of DoCoMo′s i-Mode Service (기술언어가 m-commerce의 성공에 미치는 영향에 관한 소고 - i-mode 서비스를 중심으로 -)

  • 김광희
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2001.06a
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    • pp.305-314
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    • 2001
  • 본 논문해서는 m-커머스의 대표적인 성공 사례로 꼽히고 있는 NTT DoCOMo의 i-mode 서비스에 초점을 맞추어 성공요인과 그러한 성공을 이끌어 내는데 결정적인 역할을 담당한 웹 페이지 기술언어에 대해 살펴보았다. 분석 결과에 근거하면, i-mode 서비스의 대대적인 성공은 끊임없이 Positive Feedback의 계기를 만들어 냄으로써 가능하게 되었는데, 그것은 다름 아닌 C-HTML이라는 웹페이지 기술언어의 채용이 많은 역할을 하고 있다.

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Study of Absorbed Dose and Effective Dose for Prostate Cancer Image Guided Radiation Therapy using kV Cone Beam Computed Tomography (kV Cone Beam Computed Tomography (CBCT)를 이용한 전립선암 영상유도방사선치료 시 흡수선량 및 유효선량에 관한 고찰)

  • Na, Jong-Eok;Lee, Do-Geun;Kim, Jin-Soo;Baek, Geum-Mun;Kwon, Kyung-Tae
    • The Journal of Korean Society for Radiation Therapy
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    • v.21 no.2
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    • pp.67-74
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    • 2009
  • Purpose: To evaluate the results of absorbed and effective doses using two different modes, standard mode (A-mode) and low-dose mode (B-mode) settings for prostate cancer IGRT from CBCT. Materials and Methods: This experimental study was obtained using Clinac iX integrated with On Board Imager (OBI) System and CBCT. CT images were obtained using a GE Light Speed scanner. Absorbed dose to organs from ICRP recommendations and effective doses to body was performed using A-mode and B-mode CBCT. Measurements were performed using a Anderson rando phantom with TLD-100 (Thermoluminescent dosimeters). TLD-100 were widely used to estimate absorbed dose and effective dose from CBCT with TLD System 4000 HAWSHAW. TLD-100 were calibrated to know sensitivity values using photon beam. The measurements were repeated three times for prostate center. Then, Evaluations of effective dose and absorbed dose were performed among the A-mode and B-mode CBCT. Results: The prostate absorbed dose from A-mode and B mode CBCT were 5.5 cGy 1.1 cGy per scan. Respectively Effective doses to body from A mode and B-mode CBCT were 19.1 mSv, 4.4 mSv per scan. Effective dose from A-mode CBCT were approximately 4 times lower than B-mode CBCT. Conclusion: We have shown that it is possible to reduce the effective dose considerably by low dose mode(B-mode) or lower mAs CBCT settings for prostate cancer IGRT. Therefore, we should try to select B-mode or low condition setting to decrease extra patient dose during the IGRT for prostate cancer as possible.

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A Study on Changes in Body Surface Temperature and Thermal Effect According to Ultrasound Mode (초음파 진단모드에 따른 체표면 온도변화와 열효과에 관한 고찰)

  • Yang, Sung-Hee;Lee, Jin-Soo
    • Journal of radiological science and technology
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    • v.40 no.2
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    • pp.213-218
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    • 2017
  • Recently, as the number of high-risk pregnancies increases, the use of new techniques such as Doppler, which have higher acoustic power than in the past, has been increasingly used in prenatal diagnosis and guidelines have been set up by various organizations to prevent excessive exposure. Therefore, in this study, we tried to investigate the temperature change of the body surface for each test mode according to the long time ultrasound examination and to examine the exposure time which is not influenced by the thermal effect. B mode, C mode, and PD mode according to time, and the temperature difference between exposed and unexposed sites were compared. As a result, the B mode showed a significant difference in the temperature change from 10 minutes, 50 minutes after exposed, 20 minutes from the C mode, and 30 minutes from the PD mode (p<0.01). In all three modes, the temperature difference was different (p<0.000), and PD mode was the most sensitive to temperature change. Also, it was found that the temperature rise time was shortened with the increase of the ultrasonic exposure time. Therefore, it is recommended that ultrasonography to observe the embryo or fetus should be used only for diagnostic purposes, avoiding excessive test time.