scholarly journals Benchmarking of Siemens Linac in Electron Modes: 8-14 MeV Electron Beams

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
H Dowlatabadi ◽  
A A Mowlavi ◽  
M Ghorbani ◽  
S Mohammadi ◽  
F Akbari
Keyword(s):  
Monte Carlo ◽  
Radiation Treatment ◽  
Electron Beams ◽  
Dose Profile ◽  
Depth Dose ◽  
Mcnpx Code ◽  
Gamma Index ◽  
Simulation Results ◽  
Mc Simulation ◽  
Good Agreement

Introduction: Radiation therapy using electron beams is a promising method due to its physical dose distribution. Monte Carlo (MC) code is the best and most accurate technique for forespeaking the distribution of dose in radiation treatment of patients.Materials and Methods: We report an MC simulation of a linac head and depth dose on central axis, along with profile calculations. The purpose of the present research is to carefully analyze the application of MC methods for the calculation of dosimetric parameters for electron beams with energies of 8–14 MeV at a Siemens Primus linac. The principal components of the linac head were simulated using MCNPX code for different applicators. Results: The consequences of measurements and simulations revealed a good agreement. Gamma index values were below 1 for most points, for all energy values and all applicators in percent depth dose and dose profile computations. A number of states exhibited rather large gamma indices; these points were located at the tail of the percent depth dose graph; these points were less used in in radiotherapy. In the dose profile graph, gamma indices of most parts were below 1. The discrepancies between the simulation results and measurements in terms of Zmax, R90, R80 and R50 were insignificant. The results of Monte Carlo simulations showed a good agreement with the measurements. Conclusion: The software can be used for simulating electron modes of a Siemens Primus linac when direct experimental measurements are not feasible.

scholarly journals Grid Monte Carlo Simulation of a Medical Linear Accelerator

2018 ◽  
Vol 3 (12) ◽  
pp. 40-43 ◽  
Author(s):  
Didi Samir ◽  
Mustapha Zerfaoui ◽  
Abdelilah Moussa ◽  
Yassine Benkhouya ◽  
Mehdi El Ouartiti
Keyword(s):  
Monte Carlo ◽  
Linear Accelerator ◽  
Field Size ◽  
Dose Profile ◽  
Depth Dose ◽  
Grid Simulation ◽  
Medical Linear Accelerator ◽  
Measured Dose ◽  
Better Than ◽  
Good Agreement

A full grid simulation of the head of an Elekta Synergy Platform medical linear accelerator is performed using the Geant4 Monte Carlo platform. The simulation includes all components of the accelerator head and a homogeneous water phantom. Results in terms of depth doses and lateral dose profiles are presented for 6 MV photon beam with the 10x10 cm2 reference field size at 100 cm distance from the source. Overall, a good agreement with the measured dose data is achieved with a precision better than 0.93% and 2.63% for the depth dose profile and lateral dose profiles respectively.

Simulation of Microstructure and Grain Size in Welding Heat Affected Zone Using Monte Carlo Method

2011 ◽  
Vol 194-196 ◽  
pp. 121-126
Author(s):  
Shi Xing Zhang ◽  
Gang Yi Cai
Keyword(s):  
Grain Size ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Kinetic Model ◽  
Grain Growth ◽  
Growth Process ◽  
Great Influence ◽  
Simulation Results ◽  
Mc Simulation ◽  
Good Agreement

In this paper, modeling, procedure and algorithm using Monte Carlo (MC) technology were investigated respectively to simulate grain size and microstructure . First, two different kinetic model were defined by both experimental and statistics method. Then the procedure and algorithm were worked out based on MC technology. Thirdly, the grain growth process in HAZ was simulated, which has great influence on grain growth in HAZ. The result of the simulation demonstrates the grain growth process dynamically. Good agreement between MC simulation results and the experimental results was obtained which can provide a reliable evidence for evaluating the welding craft and the weldability.

scholarly journals Dosimetric Algorithm to Reproduce Isodose Curves Obtained from a LINAC

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Julio Cesar Estrada Espinosa ◽  
Segundo Agustín Martínez Ovalle ◽  
Cinthia Kotzian Pereira Benavides
Keyword(s):  
Monte Carlo ◽  
Absorbed Dose ◽  
Numerical Data ◽  
Radiation Beam ◽  
Calculation Time ◽  
Water Phantom ◽  
Percentage Depth Dose ◽  
Dose Profile ◽  
Depth Dose ◽  
Mcnpx Code

In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD) and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel’s size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel’s size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo.

Monte Carlo simulation of electron modes of a Siemens Primus linac (8, 12 and 14 MeV)

2013 ◽  
Vol 12 (4) ◽  
pp. 352-359 ◽  
Author(s):  
Mohammad Taghi Bahreyni Toossi ◽  
Mahdi Ghorbani ◽  
Fateme Akbari ◽  
Leila Sobhkhiz Sabet ◽  
Mohammad Mehrpouyan
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Measured Data ◽  
Depth Dose ◽  
Gamma Index ◽  
Phantom Measurements ◽  
Electron Mode ◽  
Data Points ◽  
Comparison Of The Results ◽  
Good Agreement

AbstractBackgroundElectron mode is used for treatment of superficial tumours in linac-based radiotherapy.PurposeThe aim of present study is simulation of 8, 12 and 14 MeV electrons from a Siemens Primus linac using MCNPX Monte Carlo (MC) code and verification of the results based on comparison of the results with the measured data.Materials and methodsElectron mode for 8, 12 and 14 MeV electron energies of a Siemens Primus linac was simulated using MCNPX MC code. Percent depth dose (PDD) data for 10 × 10, 15 × 15 and 25 × 25 cm2 applicators obtained from MC simulations were compared with the corresponding measured data.ResultsGamma index values were less than unity in most of points for all the above-mentioned energies and applicators. However, for 25 × 25 cm2 applicator in 8 MeV energy, 10 × 10 cm2 applicator and 15 × 15 cm2 applicator in 14 MeV energy, there were four data points with gamma indices higher than unity. However among these data points, there are a number of cases with relatively large value of gamma index, these cases are positioned on the bremsstrahlung tail of the PDD curve which is not normally used in treatment planning.ConclusionThere was good agreement between the results of MC simulations developed in this study and the measured values. The obtained simulation programmes can be used in dosimetry of electron mode of Siemens Primus linac in the cases in which it is not easily feasible to perform experimental in-phantom measurements.

scholarly journals Validation of the Analytical Model of Oceanic Lidar Returns: Comparisons with Monte Carlo Simulations and Experimental Results

2019 ◽  
Vol 11 (16) ◽  
pp. 1870 ◽  
Author(s):  
Yudi Zhou ◽  
Weibiao Chen ◽  
Xiaoyu Cui ◽  
Aleksey Malinka ◽  
Qun Liu ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Analytical Model ◽  
Oblique Incidence ◽  
Relative Difference ◽  
Experimental Results ◽  
Coefficient Of Determination ◽  
Scattering Approximation ◽  
Angle Scattering ◽  
Mc Simulation ◽  
Good Agreement

The analytical model based on the quasi-single small-angle scattering approximation can efficiently simulate oceanic lidar signals with multiple scattering; thus, its accuracy is of particular interest to scientists. In this paper, the model is modified to include refraction at oblique incidence and is then compared with Monte Carlo (MC) simulations and experimental results. Under different conditions, the results calculated by the analytical model demonstrate good agreement with the MC simulation and experimental data. The coefficient of determination R2 considering the logarithm of signals and the root mean square of the relative difference δ are R2 = 0.998 and δ = 10% in comparison with the semi-analytic MC simulation and R2 = 0.952 and δ = 46% for the lidar experiment. Thus, the results demonstrate the validity of the analytical model in the simulation of oceanic lidar signals.

Monte-Carlo Modeling of Grain Growth of Plain Carbon Strip Steel Q235 during Heating Process

2012 ◽  
Vol 538-541 ◽  
pp. 869-872 ◽  
Author(s):  
Hong Yan Ma ◽  
Chun Li Mo ◽  
Shou Peng Du
Keyword(s):  
Monte Carlo ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Heating Process ◽  
Kinetics Equation ◽  
Grain Distribution ◽  
Simulation Results ◽  
Mc Simulation ◽  
Grain Growth Kinetics ◽  
Reheating Process

The grain growth kinetics of Q235 during reheating process was studied with Monte Carlo (MC) simulation. Heating process was performed at 1223K, 1273K, 1323K, 1373K, 1473K and 1523K for 10s, 20s, 40s, 80s, 120s, respectively. Samples were tested on Gleeble 1500 thermal simulation tester. The experimental results were analyzed regressively to obtain grain growth kinetics equation. The kinetics equation of Q235 was introduced to MC simulation to simulate the microstructure evolution and compute the average grain size at different step during heating process. MC simulation results showed the grain distribution under different time and the grain growth is in consistent with physical simulation. The simulation results also can help to set processing parameters during reheating of ingot.

Modelling of Grain Boundary Stability of Materials under Severe Plastic Deformation and Experimental Verification

2010 ◽  
Vol 638-642 ◽  
pp. 2724-2729
Author(s):  
Yoshiyuki Saito ◽  
Chitoshi Masuda
Keyword(s):  
Monte Carlo ◽  
Grain Boundary ◽  
Computer Simulations ◽  
Phase Field ◽  
Field Methods ◽  
Simulation Results ◽  
Boundary Stability ◽  
Textured Materials ◽  
Phase Field Methods ◽  
Good Agreement

Thermodynamic stability of Grain boundary in materials under severe plastic deformation was simulated by the Monte Carlo and the phase field methods. Computer simulations were performed on 3-dimensional textured materials. The Monte Carlo simulation results were qualitatively in good agreement with those by the phase field model. The classification of the solution of differential equations based on the mean-field Hillert model describing temporal evolution of the scaled grain size distribution function was in good agreement with those given by the Computer simulations. The ARB experiments were performed for pure Al and Al alloys-sheets in order to validate the computer simulation results concerning the grain boundary stability of textured materials. With use of the Monte Carlo and the phase field methods. Effect of grain boundary mobilises and interface energy given by the computer simulations.

Comparison of MCNP4C and EGSnrc Monte Carlo codes in depth-dose calculation of low energy clinical electron beams

2007 ◽  
Vol 40 (15) ◽  
pp. 4519-4524 ◽  
Author(s):  
N Jabbari ◽  
B Hashemi-Malayeri ◽  
A R Farajollahi ◽  
A Kazemnejad ◽  
A Shafaei ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Electron Beams ◽  
Dose Calculation ◽  
Low Energy ◽  
Depth Dose

Drift velocity in GaN semiconductors: Monte Carlo simulation and comparison with experimental measurements

2020 ◽  
Vol 26 (4) ◽  
pp. 263-271
Author(s):  
Evgenia Kablukova ◽  
Karl Sabelfeld ◽  
Dmitrii Y. Protasov ◽  
Konstantin S. Zhuravlev
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Electron Transport ◽  
Drift Velocity ◽  
Experimental Studies ◽  
Experimental Measurements ◽  
Deformation Potential ◽  
Monte Carlo Algorithms ◽  
Simulation Results ◽  
Good Agreement

AbstractMonte Carlo algorithms are developed to simulate the electron transport in semiconductors. In particular, the drift velocity in GaN semiconductors is calculated, and a comparison with experimental measurements is discussed. Explicit expressions for the scattering probabilities and distributions of the scattering angle of electrons on polar optical and intervalley phonons, and acoustic deformation potential as well are given. A good agreement of the simulation results and the experimental measurements reveals that the M-L valley is located at 0.7 eV higher than the Γ-valley. This value agrees with other experimental studies, while it is lower compared to ab initio calculations.

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