• Title, Summary, Keyword: 몬테칼로 전산모사

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Development of Reference Korean Organ and Effective Dose Calculation Online System (웹 기반 표준한국인 장기 흡수선량 및 유효선량 평가 시스템 개발)

  • Park, Sooyeun;Yeom, Yeon Soo;Kim, Jae Hyeon;Lee, Hyun Su;Han, Min Cheol;Jeong, Jong Hwi;Kim, Chan Hyeong
    • Journal of Radiation Protection and Research
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    • v.39 no.1
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    • pp.30-37
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    • 2014
  • Recently High-Definition Reference Korean-Man (HDRK-Man) and High-Definition Reference Korean-Woman (HDRK-Woman) were constructed in Korea. The HDRK phantoms were designed to represent respectively reference Korean male and female to calculate effective doses for Korean by performing Monte Carlo dose calculation. However, the Monte Carlo dose calculation requires detailed knowledge on computational human phantoms and Monte Carlo simulation technique which regular researchers in radiation protection dosimetry and practicing health physicists do not have. Recently the UFPE (Federal University of Pernambuco) research group has developed, and opened to public, an online Monte Carlo dose calculation system called CALDOSE_X(www.caldose.org). By using the CALDOSE_X, one can easily perform Monte Carlo dose calculations. However, the CALDOSE_X used caucasian phantoms to calculate organ doses or effective doses which are limited for Korean. The present study developed an online reference Korean dose calculation system which can be used to calculate effective doses for Korean.

즉발감마선을 이용한 70MeV 양성자선량 급락지점 위치 측정에 관한 연구

  • Seo, Gyu-Seok;Kim, Jong-Won;Kim, Ju-Yeong;Min, Cheol-Hui;Jo, Seong-Gu;Kim, Chan-Hyeong
    • Proceedings of the Korean Society of Medical Physics Conference
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    • pp.100-102
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    • 2005
  • 양성자 빔을 이용한 치료는 종양부위에 높은 선량을 균일하게 전달하고 정상세포에는 적은 선량을 전달할 수 있어 암치료 효과가 높으나 정확한 치료와 환자의 안전을 위해서는 양성자선량의 급락지점을 정확히 아는 것이 중요하다. 본 연구에서는 양성자와 물질과의 핵반응으로 직각방향으로 방출되는 즉발감마선을 측정하여 양성자선량 급락지점을 측정할 수 있는 검출시스템을 몬테칼로 전산코드로 전산모사하였으며, 70MeV 단일에너지 빔과 최대에너지가 70MeV인 SOBP 빔을 모의피폭체인 물팬텀에 조사하고 검출시스템을 통해 직각방향으로 방출되는 즉발감마선의 분포를 계산하였다. 모의피폭체 안에서의 양성자선량의 분포와 측정된 즉발감마선의 분포를 서로 비교하여 두 분포 사이의 상관관계를 찾고 이 상관관계를 이용하여 양성자선량 급락지점을 결정할 수 있음을 확인할 수 있었다.

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Development of a Proton Computed Tomography System with Monte Carlo Simulation (양성자 전산화 단층 촬영 장치 개발에 관한 전산모사 연구)

  • Seo, Jeong-Min;Kim, Chan-Hyeong
    • Journal of radiological science and technology
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    • v.34 no.3
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    • pp.215-219
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    • 2011
  • Monte Carlo simulation was performed to investigate optimal system of proton computed tomography and to avoid the errors by using data from X ray computed tomography in proton therapy. The informations from two DSSDs to measure position and LYSO scintillation detector to measure the residual energy of proton particle in GEANT4 were used for reconstruction computed tomography.

Diagnostic X-ray Spectra Detection by Monte Carlo Simulation (진단용 X-선 스펙트럼의 몬테칼로 전산모사 측정)

  • Baek, Cheol-Ha;Lee, Seung-Jae;Kim, Daehong
    • Journal of the Korean Society of Radiology
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    • v.12 no.3
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    • pp.289-295
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    • 2018
  • Most diagnostic devices in the medical field use X-ray sources, which emit energy spectra. In radiological diagnosis, the quantitative and qualitative analyses of X-rays are essential for maintaining the image quality and minimizing the radiation dose to patients. This work aims to obtain the X-ray energy spectra used in diagnostic imaging by Monte Carlo simulation. Various X-ray spectra are simulated using a Monte Carlo simulation tool. These spectra are then compared to the reference data obtained with a tungsten anode spectral model using the interpolating polynomial (TASMIP) code. The X-ray tube voltages used are 50, 60, 80, 100, and 110 kV, respectively. CdTe and a-Se detector are used as the detectors for obtaining the X-ray spectra. Simulation results demonstrate that the various X-ray spectra are well matched with the reference data. Based on the simulation results, an appropriate X-ray spectrum, in accordance with the tube voltage, can be selected when generating an image for diagnostic imaging. The dose to be delivered to the patient can be predicted prior to examination in the diagnostic field.

Monte Carlo Simulation of a Varian 21EX Clinac 6 MV Photon Beam Characteristics Using GATE6 (GATE6를 이용한 Varian 21EX Clinac 선형가속기의 6 MV X-선 특성모사)

  • An, Jung-Su;Lee, Chang-Lae;Baek, Cheol-Ha
    • Journal of radiological science and technology
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    • v.39 no.4
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    • pp.571-575
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    • 2016
  • Monte Carlo simulations are widely used as the most accurate technique for dose calculation in radiation therapy. In this paper, the GATE6(Geant4 Application for Tomographic Emission ver.6) code was employed to calculate the dosimetric performance of the photon beams from a linear accelerator(LINAC). The treatment head of a Varian 21EX Clinac was modeled including the major geometric structures within the beam path such as a target, a primary collimator, a flattening filter, a ion chamber, and jaws. The 6 MV photon spectra were characterized in a standard $10{\times}10cm^2$ field at 100 cm source-to-surface distance(SSD) and subsequent dose estimations were made in a water phantom. The measurements of percentage depth dose and dose profiles were performed with 3D water phantom and the simulated data was compared to measured reference data. The simulated results agreed very well with the measured data. It has been found that the GATE6 code is an effective tool for dose optimization in radiotherapy applications.

Development of an MCNP-Based Cone-Beam CT Simulator (MCNP 기반의 CBCT 전산모사 시스템 개발)

  • Lim, Chang-Hwy;Cho, Min-Kook;Han, Jong-Chul;Youn, Han-Bean;Yun, Seung-Man;Cheong, Min-Ho;Kim, Ho-Kyung
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.4
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    • pp.351-359
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    • 2009
  • We have developed a computer simulator fur cone-beam computed tomography (CBCT) based on the commercial Monte Carlo code, MCNP. All the functions to generate input files, run MCNP, convert output files to image data, reconstruct tomographs were realized in graphical user-interface form. The performance of the simulator was demonstrated by comparing with the experimental data. Although some discrepancies were observed due to the ignorance of the detailed physics in the simulation, such as scattered X-rays and noise in image sensors, the overall tendency was well agreed between the measured and simulated data. The developed simulator will be very useful for understanding the operation and the better design of CT systems.

Study on the 6 MV Photon Beam Characteristics and Analysis Method from Medical Linear Accelerators Using Geant4 Medical Linac2 Example (GEANT4 Medical Linac2 예제를 이용한 6 MV 선형가속기 광자선속의 기초특성과 연구방법)

  • Kim, Byung-Yong;Kim, Hyung-Dong;Kim, Sung-Jin;Oh, Se-An;Kang, Jung-Gu;Kim, Sung-Kyu
    • Progress in Medical Physics
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    • v.22 no.2
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    • pp.79-84
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    • 2011
  • In this study, Geant4 based Monte Carlo simulations were carried out for medical linear accelerator. Modified Medical Linac2 toolkit was used for calculation. The energy spectrum, most probable energy and the photon mean energy compared with the published results using the EGS4 code. The results well agreed with published results. The calculated results of photon fluence, energy fluence and mean energy according to the radius from the centre of the beam were analyzed. Monte Carlo simulation using Medical Linac2 code is considered to be useful for analysis of medical linear accelerator. Because the calculated results varies depending on Physics List model for same head structure. It it important to choose the right model for research purpose. Monte Carlo simulation using GEANT4 Medical Linac2 is a valuable for any novice to adopt this code to the study related to 6 MV photon fluence from medical linear accelerator.

A Monte Carlo Simulation for the Newly Developed Head-and-Neck IMRT Phantom: a Pilot Study (제작된 선량 검증용 IMRT 팬텀의 몬테칼로 시뮬레이션: 예비적 연구)

  • Kang, Sei-Kwon;Cheong, Kwang-Ho;Ju, Ra-Hyeong;Cho, Byung-Chul;Oh, Do-Hoon;Kim, Su-SSan;Kim, Kyoung-Ju;Bae, Hoon-Sik;Han, Young-Yih;Shin, Eun-Hyuk;Park, Sung-Ho;Lim, Chun-Il
    • Progress in Medical Physics
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    • v.18 no.3
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    • pp.126-133
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    • 2007
  • A head-and-neck phantom was designed in order to evaluate remotely the quality of the delivery dose of intensity modulated radiation therapy (IMRT) in each institution. The phantom is homogeneous or inhomogeneous by interchanging the phantom material with the substructure like an air or bone plug. Monte Carlo simulations were executed for one beam and three beams to the phantom and compared with ion chamber and thermoluminescent dosimeter (TLD) measurements of which readings were from two independent institutions. For single beam, the ion chamber results and the MC simulations agreed to within about 2% TLDs agreed with the MC results to within 2% or 7% according to which institution read the TLDs. For three beams, the ion chamber results showed -5% maximum discrepancy and those of TLDs were $+2{\sim}+3%$. The accuracy of the TLD leadings should be increased for the remote dose monitoring. MC simulations are a valuable tool to acquire the reliability of the measurements in developing a new phantom.

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Development of Unfolding Energy Spectrum with Clinical Linear Accelerator based on Transmission Data (물질투과율 측정정보 기반 의료용 선형가속기의 에너지스펙트럼 유도기술 개발)

  • Choi, Hyun Joon;Park, Hyo Jun;Yoo, Do Hyeon;Kim, Byoung-Chul;Yi, Chul-Young;Min, Chul Hee
    • Journal of Radiation Protection and Research
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    • v.41 no.1
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    • pp.41-47
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    • 2016
  • Background: For the accurate dose assessment in radiation therapy, energy spectrum of the photon beam generated from the linac head is essential. The aim of this study is to develop the technique to accurately unfolding the energy spectrum with the transmission analysis method. Materials and Methods: Clinical linear accelerator and Monet Carlo method was employed to evaluate the transmission signals according to the thickness of the observer material, and then the response function of the ion chamber response was determined with the mono energy beam. Finally the energy spectrum was unfolded with HEPROW program. Elekta Synergy Flatform and Geant4 tool kits was used in this study. Results and Discussion: In the comparison between calculated and measured transmission signals using aluminum alloy as an attenuator, root mean squared error was 0.43%. In the comparison between unfolded spectrum using HEPROW program and calculated spectrum using Geant4, the difference of peak and mean energy were 0.066 and 0.03 MeV, respectively. However, for the accurate prediction of the energy spectrum, additional experiment with various type of material and improvement of the unfolding program is required. Conclusion: In this research, it is demonstrated that unfolding spectra technique could be used in megavoltage photon beam with aluminum alloy and HEPROW program.