• Title, Summary, Keyword: radiation pattern

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Analysis of changes in dose distribution due to respiration during IMRT

  • Shin, Jung-Suk;Shin, Eun-Hyuk;Han, Young-Yih;Ju, Sang-Gyu;Kim, Jin-Sung;Ahn, Sung-Hwan;Kim, Tae-Gyu;Jeong, Bae-Kwon;Park, Hee-Chul;Ahn, Young-Chan;Choi, Doo-Ho
    • Radiation Oncology Journal
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    • v.29 no.3
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    • pp.206-213
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    • 2011
  • Purpose: Intensity modulated radiation therapy (IMRT) is a high precision therapy technique that can achieve a conformal dose distribution on a given target. However, organ motion induced by respiration can result in significant dosimetric error. Therefore, this study explores the dosimetric error that result from various patterns of respiration. Materials and Methods: Experiments were designed to deliver a treatment plan made for a real patient to an in-house developed motion phantom. The motion pattern; the amplitude and period as well as inhale-exhale period, could be controlled by in-house developed software. Dose distribution was measured using EDR2 film and analysis was performed by RIT113 software. Three respiratory patterns were generated for the purpose of this study; first the 'even inhale-exhale pattern', second the slightly long exhale pattern (0.35 seconds longer than inhale period) named 'general signal pattern', and third a 'long exhale pattern' (0.7 seconds longer than inhale period). One dimensional dose profile comparisons and gamma index analysis on 2 dimensions were performed. Results: In one-dimensional dose profile comparisons, 5% in the target and 30% dose difference at the boundary were observed in the long exhale pattern. The center of high dose region in the profile was shifted 1 mm to inhale (caudal) direction for the 'even inhale-exhale pattern', 2 mm and 5 mm shifts to exhale (cranial) direction were observed for 'slightly long exhale pattern' and 'long exhale pattern', respectively. The areas of gamma index >1 were 11.88 %, 15.11%, and 24.33% for 'even inhale-exhale pattern', 'general pattern', and 'long exhale pattern', respectively. The long exhale pattern showed largest errors. Conclusion: To reduce the dosimetric error due to respiratory motions, controlling patient's breathing to be closer to even inhaleexhale period is helpful with minimizing the motion amplitude.

The effective of Radiation Pattern on Two Shape of Slot Antenna

  • Chanwattanapong, W.;Anantrasirichai, N.;Wakabayachi, T.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1660-1663
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    • 2003
  • This paper present the characteristics of radiation pattern of microstrip slot antenna on the ground plane fed by microstrip line. It is proposed for resonance frequency at 10 GHz. We will analysis two shape of slot antenna; double L-shape slot antenna and U-shape slot antenna. In this case, we will compare far-field radiation pattern of two shape slot antenna. Far-field radiation pattern of double L-shape slot antenna is bi-directional nevertheless U-shape slot antenna is uni-directional. The microstrip slot antenna is propose to analyze far-field radiation pattern for use in the wireless communication systems

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Radiation pattern optimization of the multi-band helical antenna used in the mobile phone. (휴대폰에 사용되는 다중대역 헬리컬 안테나의 방사패턴 최적화)

  • 김용석
    • Proceedings of the IEEK Conference
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    • pp.254-257
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    • 2003
  • 본 논문에서는 휴대폰에 사용되는 Multi-band 용 helical antenna 의 radiation pattern 을 체적화하기 위한 방법을 제안하고자 하였다. 일반적으로 GSM 휴대폰에 사용되는 안테나는 GSM, DCS 의 dual band 인 경우가 다수이며 추세에 따라 요즘은 PCS 등을 포함한 triple band 의 안테나가 많이 선호되고 있다. 이러한 multi band antenna 의 radiation pattern 에 영향을 미치는 변수로 본 논문에서는 ground 의 length 와 width 그리고 폴더쪽에 사용되는 LCD 의 ground 와 폴더쪽 기구물에 사용된 EMI spray 등의 변화를 통해 pattern 의 변화를 알아보고 이러한 변수를 조절하여 radiation pattern을 최적화하는 방법에 관하여 논하였다.

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Radiation Pattern of the Vibrox Transducer (자외성 페라이트 진동자의 지향특성에 대하여)

  • 신형일
    • Journal of the Korean Institute of Navigation
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    • v.4 no.2
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    • pp.1-6
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    • 1980
  • Computer simulation results on the radiation pattern of an ultrasonic beam by the plurall arrangement of the transducers were reported by Sin (1979). This paper describes on the measurement of radiation pattern in case of one vibrox transducer and two vibrox transducers by varying the interval between the transducers. The measured results obtained are as follows; 1. Radiation wave of ultrasonic transducer is propagated to diffuse with spherical wave from center of transducer. 2. In case of one vibrox transducer, the greater the length of transducer, the sharper becomes the radiation pattern. 3. In case of two vibrox transducers, the maine lobe is revealed at the center of two transducers, it is shown difficult to make control freely of radiation pattern by varying merely the interval of transducers.

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The Mirror Active Element Pattern Method for The Radiation Pattern Computation of Linear Array Antennas (선형 배열 안테나의 방사패턴 계산을 위한 Mirror Active Element Pattern 방법)

  • Kim, Jae-Hyun;Yoon, Young-Min;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.8
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    • pp.94-102
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    • 2013
  • We propose the mirror active element pattern (AEP) method for the radiation pattern computation of linear array antennas versus scan angles. The computation time for the radiation pattern of linear array antennas using the mirror AEP method is reduced by almost half compared to that using the AEP method because the number of AEPs of elements obtained by the full-wave simulation necessary for the radiation pattern computation of linear array antennas is reduced by almost half. The difference between the radiation patterns of linear array antennas obtained by the full-wave simulation and mirror AEP method is very small for wide scan angle range when the radiation pattern of an antenna element is symmetric.

A Study on the method for the extraction of the radiation efficiency and radiation direction coefficient (방사효율과 방사방향 계수 산출기법 연구)

  • Jung, Woo-Jin;Kang, Myung-hwan;Lee, Jong-Ju;Jeon, Jae-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.738-743
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    • 2013
  • Underwater radiated noise is the key in acoustic stealth performance of modern naval ships. The underwater radiated noise predicted by the hull vibration with radiation efficiency cannot give the information of radiation pattern which is essential to the analysis of detection possibility by enemy and to improve the operational performance of the naval ship. The radiation pattern of underwater radiated noise is able to be obtained with radiation efficiency and radiation direction coefficient. In this paper, a new method to extraction the radiation efficiency and radiation direction coefficient is suggested and proved with the simulation and experiment by using cylindrical shell of 70cm diameter in air.

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A New Extraction Method for the Radiation Efficiency and Radiation Directional Coefficient (방사효율과 방사방향 계수에 대한 새로운 산출기법 연구)

  • Jung, Woo-Jin;Lee, Jong-Ju;Kang, Myung-Hwan;Jeon, Jae-Jin
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.2
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    • pp.93-101
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    • 2014
  • Underwater radiated noise is the key in acoustic stealth performance of modern naval ships. The underwater radiated noise predicted by the hull vibration with radiation efficiency cannot always give the information of radiation pattern which is essential to analyze of detection probability by enemy and to improve the operational performance of the naval ship. The radiation pattern of underwater radiated noise is able to be obtained with radiation efficiency and radiation directional coefficient. In this paper, a new method to extract the radiation efficiency and radiation directional coefficient is suggested and proved with the simulation and experiment by using cylindrical shell of 70 cm diameter in air.

Theoretical Calculation on Radiation Patterns of Epi-signal in CARS Microscopy (간섭성 반스톡스 라만 산란 현미경 후방 신호지 방사패턴에 관한 이론계산 연구)

  • Yoo, Yong-Shim;Cho, Hyuck
    • Korean Journal of Optics and Photonics
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    • v.18 no.4
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    • pp.286-291
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    • 2007
  • We theoretically investigated the far-field radiation pattern of epi-signal from a polystyrene sphere in coherent anti-Stokes Raman scattering (CARS) microscopy with an objective lens of high numerical aperture. We calculated the field distribution of the incident laser beams under the tight-focusing condition and the far-field radiation pattern through coherent addition of radiation from the nonlinear polarizations (Hertzian dipoles) as the origin of CARS signal generation. The epi-radiation patterns for polystyrene spheres of different diameters are calculated, and the pattern of a sphere is also compared with that of a shell fer a diameter of 1100 nm. We finally show how the radiation pattern of the polystyrene sphere changes as the center of the sphere shifts from the focus of the beam.

A study on the radiation pattern analysis of the monopole antenna mounted on a portable phone (휴대전화기에 장착된 모노폴안테나의 방사패턴 해석에 관한 연구)

  • 정옥현;문영찬;윤상원;장익수
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.12
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    • pp.16-24
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    • 1996
  • In this paper, the radiation pattern of the monopole antenna mounted on the portable phone is analyzed. The analyzed model consists of a rectangular conductor box and a monopole antenna. Even though the radiation pattern of the monopole has been well known, the monopole antenna mounted on the portable phone has not been fully studied. Because of the conductor box, portable phone acts as an unbalanced dipole antenna whoe radiation patterns deviate fro those of th econventional isolated monopole antenna. Therefore, the analysis of the radiation patterns of unbalanced dopole antenna is necessary. Using the moment method, its radiation patterns are analyzed and the numerical results are verified through the measurements. In addition, the radiation patterns depending on various length of the conductor box and the monopole antenna are also presented and the dimension of the portable phone which gives excellent radiation characteristics are derived from the analyzed results.

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Design of Radiation Pattern Reconfigurable Antenna for Vital Signal Sensing Device Attached on Wristband and SAR Analysis on Human body (팔목 부착형 생체신호 측정기기에 사용가능한 방사패턴 재구성 안테나 설계 및 인체 SAR 영향 분석)

  • Lee, Chang Min;Jung, Chang Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.666-670
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    • 2015
  • This paper presents radiation pattern reconfigurable antenna for Fitbit Flex wristband which detects vital signal. Also, the paper presents Specific Absorption Rate (SAR) from the loop-dipole radiation pattern reconfigurable antenna based on the position of human body. The proposed loop-dipole radiation pattern reconfigurable antenna produces two opposite side direction radiation pattern using two RF switches. The resonant frequency of the radiation pattern reconfigurable antenna is Bluetooth communication bandwidth (2.4 - 2.485 GHz) and the maximum gain of the proposed antenna is 1.96 dBi. The proposed antenna satisfied the standard SAR value of 1.6 W/kg in 1 g tissue of the human body when the Bluetooth communication input average power of 0.04 W is excited to five parts of human body (head, chest, stomach, back, wrist). The maximum SAR value of in this simulation is presented in the part of head.