• Title/Summary/Keyword: 직육면체형 분포

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A Study on the Rectangular Distribution of far Field Sources in Equivalent Source Method (등가음원법에서의 직육면체형 원거리음원 배치에 관한 연구)

  • 백광현
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.1
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    • pp.40-46
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    • 2004
  • The equivalent source method (ESM) uses two groups of equivalent source positions. One group includes the first order images of the sound source inside the enclosure. The positions of the other group are usually on a spherical surface some distance outside the enclosure. A proper selection of the positions for the far field sources could greatly improve the performance of the modeling accuracy and reduce the number of the sources to achieve the required accuracy. This study uses optimally distributed far field source positions on the surface of enlarged version of the rectangular enclosure instead of using typical spherical distribution. Simulations using various sizes of the box shaped distribution are executed and optimal positions are searched using an optimization technique from the larger number of candidate positions. The results of using these far field source positions are compared and analyzed.

Search of Characteristic for Dose Distribution Presented by Multi­isocentric Stereotactic Radiosurgical Plan Using Linear Accelerator (선형 가속기를 이용한 정위적 방사선 수술시 병소내 선량분포의 특성조사)

  • 최경식;오승종;이형구;최보영;전흥재;서태석
    • Progress in Medical Physics
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    • v.14 no.4
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    • pp.225-233
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    • 2003
  • The goal of a radiation treatment plan is to deliver a homogeneous dose to a target with minimal irradiation of the adjacent normal tissues. Dose uniformity is especially important for stereotactic radiosurgery using a linear accelerator. The dose uniformity and high dose delivery of a single spherical dose distribution exceed 70%. This also results with a similar stereotactic radiosurgical plan using a Gamma Knife. The dose distribution produced in a stereotactic radiosurgical plan using a Gamma Knife and Linear accelerator is spherical, and the application of the sphere packing arrangement in a real radiosurgical plan requires much time and skill. In this study, we found a characteristic of dose distribution with transformation of beam parameters that must be considered in a radiosurgical plan for effective radiosurgery. First, we assumed a cylinder type tumor model and a cube type tumor model. Secondly, the results of the tumor models were compared and analyzed with dose profiles and DVH_(Dose Volume Histogram) representative dose distribution. We found the optimal composition of beam parameters_(i.e. collimator size, number of isocenter, gap of isocenters etc.), which allowed the tumor models to be involved in the isodose curve at a high level. In conclusion, the characteristics found in this study are helpful for improving the effectiveness and speed of a radiosurgical plan for stereotactic radiosurgery.

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