Application of variance reduction techniques in EGSnrc based Monte-Carlo method

Hoang, Tuan Duc; Tài, Dương Thanh; Luong, Oanh Thi; Truong, Loan Thi Hong

doi:10.32508/stdj.v22i2.1234

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…After the MC simulation, the realistic photon beams were stored in phase-space files which have been used as input to the DOSXYZnrc to simulate dose distributions in the geometry of patients built by the CT data. The process of the simulation of the accelerator detailed in our previous studies (9,18,20,21) .…”

Section: Simulating a Hpd Siemens Primusmentioning

confidence: 99%

“…MC simulation is a statistical method that uses random numbers to simulate and contain data of every particle in beam including the charge, total energy, position, spatial and angular distribution etc., and has the ability to accurately model the complex geometries to predict the dose distribution in patient's heterogeneous anatomy (6,7) . Many general-purpose MC codes are available for radiotherapy and its applications such as IMRT, VMAT, and so on (8)(9)(10) . Benhalouche et al (2013) have successfully used GATE/Geant4 MC code to evaluate dose distribution of patient IMRT treatment planning.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A comparison of the JO-IMRT dose distribution calculated by the SOURCE 8 and 20 in the DOSXYZnrc for head-and-neck cancer

Tài

Tuan²,

Oanh

et al. 2021

Int J Radiat Res

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Background:The purpose of this study is to compare SOURCE 8 and 20 in the EGSnrc-based DOSXYZnrc Monte Carlo code for Jaws-only intensitymodulated radiation therapy (JO-IMRT) dose distribution, and demonstrate the advantage of SOURCE 20 to SOURCE 8 to treat head-and-neck cancer. Materials and Methods:The clinical photon beams of the HPD Siemens Primus linear accelerator simulated using the BEAMnrc code and then verified by measurement. The phase-space files generated by the BEAMnrc code were used as an input for the DOSXYZnrc to calculate the JO-IMRT dose distributions of patients (in form of CT images) using the SOURCES 8 and 20. The isodose distribution on slices, DVH and gamma index (3%/3 mm, 2%/2 mm, and 1%/1 mm) were compared with Monte Carlo and treatment planning system (TPS) results. Furthermore, the efficient computation of dose distributions such as time running, working load and uncertainty error calculation also considered for evaluation. Results: JO

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Section: Simulating a Hpd Siemens Primusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A comparison of the JO-IMRT dose distribution calculated by the SOURCE 8 and 20 in the DOSXYZnrc for head-and-neck cancer

Tài

Tuan²,

Oanh

et al. 2021

Int J Radiat Res

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“…Mohammed et al (2016) studied the effect of reducing the time and the variance (statistical error) of simulation using different variance reduction techniques (VRTs) on simulation results obtained with EGSnrc (Mohammed et al, 2016). Another studies was compared the presence and effect of VRTs to the EGSnrc simulation (Shanmugasundaram & Chandrasekaran, 2018;Tuan et al, 2019). Other than that, optimal efficiency improving techniques (EITs) parameter selection depends on the simulation geometry and xray source in egs_cbct (Thing & Mainegra-Hing, 2014).…”

Section: Introductionmentioning

confidence: 99%

egs++: Optimization of Simulation Transport Parameters

Yani¹

2023

J. Ilmu Fis.

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MC transport parameters used are common to all egs++ applications. The eﬀect of each transport parameter need to understand to optimize the simulation process. Therefore, the purpose of this study was to investigate the efficiency of egs++ simulation for different transport parameters in water phantom. This water phantom has built using slab. Collimated source defined 100 cm above the phantom. The simulation parameters such as the efficiency, statistical uncertainty, and accuracy of selecting transport parameters such as electron and photon cut-oﬀ energies, spin eﬀects, atomic relaxations, and bound Compton scattering was investigated. The selection of ECUT and PCUT greatly affects the simulation time. The simulation time, efficiency and energy fractions have same value for varied ECUT except for 0.521 MeV. The energy fraction have been shifted but the simulation time and efficiency were same. Turning on spin effects in this simulation increases simulation time by 25%. The simulation time increases by about 15% when relaxations are turned on. The more accurate result of deposited energy using EGSnrc algorithm is about 30% slower than the less accurate PRESTA-I algorithm. Therefore, The optimization of transport parameters is needed in the simulation of egs++ to provide the best efficiency.

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“…Various variance reduction methods have been presented in the literature [3], out of which only a few discuss simulation geometry as the primary motivator behind variance reduction. The radiation source, such as a linear accelerator, provides an opportunity to utilize the geometry of its component assemblies in an attempt to make simulation more efficient.…”

Section: Introductionmentioning

confidence: 99%

Phase Plane Rotation as Variance Reduction Method in Monte Carlo Simulations of Axial-Symmetric Radiation Sources

Pecic,

Kurij,

Vićić

2023

Proceedings of 11th International Conference of the Balkan Physical Union — PoS(BPU11)

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algorithms often require large computing resources, primarily in the form of processing time. Knowledge of the underlying principles governing the simulated problem under specific circumstances allows the use of certain variance reduction methods. This work introduces a novel approach to variance reduction based on the partial axial symmetry of the clinical accelerator. The development of the title method was performed using an accelerator simulation that was divided into two phases: The first phase involves simulating the fluence through the symmetrical part of the accelerator, while the second phase involves fluence through the non-symmetrical part. Simulation outputs of the first phase in the form of phase space files were manipulated using in-house software for rotation of the intermediate phase plane. This way, multiple simulations of particle fluence from the source to the last rotationally symmetric component were effectively replaced by multiple random rotations of the phase plane. Analysis of phase plane rotation effects and usability of this approach as a variance reduction method is further investigated in the EGSnrc code. The usage of phase plane rotation increased the number of particles by the number of rotations factor, resulting in less variance of the estimated dose. However, rotation introduces artifacts that can be treated as a systematic error and these artifacts are discussed throughout this work. Qualitative analysis of the dose profiles undoubtedly shows the superiority of phase space rotations in comparison to particle recycling variance reduction. Also, notable improvement is achieved in terms of the efficiency of the simulation. The presented results demonstrate improvement in the overall accuracy of the simulation. Given the geometry-independent software solution, it is to be expected that the presented method can be applied with equal success to a variety of axial-symmetric radiation sources, and further extended to other packages for Monte Carlo simulations of radiation transport.

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Application of variance reduction techniques in EGSnrc based Monte-Carlo method

Cited by 6 publications

References 7 publications

A comparison of the JO-IMRT dose distribution calculated by the SOURCE 8 and 20 in the DOSXYZnrc for head-and-neck cancer

A comparison of the JO-IMRT dose distribution calculated by the SOURCE 8 and 20 in the DOSXYZnrc for head-and-neck cancer

egs++: Optimization of Simulation Transport Parameters

Phase Plane Rotation as Variance Reduction Method in Monte Carlo Simulations of Axial-Symmetric Radiation Sources

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