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Alhamada H, Simon S, Gulyban A, Gastelblum P, Pauly N, VanGestel D, Reynaert N. Monte Carlo as quality control tool of stereotactic body radiation therapy treatment plans. Phys Med 2021; 84:205-213. [PMID: 33771442 DOI: 10.1016/j.ejmp.2021.02.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/20/2021] [Accepted: 02/24/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE/OBJECTIVE The objective of this study was to verify the accuracy of treatment plans of stereotactic body radiation therapy (SBRT) and to verify the feasibility of the use of Monte Carlo (MC) as quality control (QC) on a daily basis. MATERIAL/METHODS Using EGSnrc, a MC model of Agility™ linear accelerator was created. Various measurements (Percentage depth dose (PDD), Profiles and Output factors) were done for different fields sizes from 1x1 up to 40x40 (cm2). An iterative model optimization was performed to achieve adequate parameters of MC simulation. 40 SBRT patient's dosimetry plans were calculated by Monaco™ 3.1.1. CT images, RT-STRUCT and RT-PLAN files from Monaco™ being used as input for Moderato MC code. Finally, dose volume histogram (DVH) and paired t-tests for each contour were used for dosimetry comparison of the Monaco™ and MC. RESULTS Validation of MC model was successful, as <2% difference comparing to measurements for all field's sizes. The main energy of electron source incident on the target was 5.8 MeV, and the full width at half maximum (FWHM) of Gaussian electron source were 0.09 and 0.2 (cm) in X and Y directions, respectively. For 40 treatment plan comparisons, the minimum absolute difference of mean dose of planning treatment planning (PTV) was 0.1% while the maximum was 6.3%. The minimum absolute difference of Max dose of PTV was 0.2% while the maximum was 8.1%. CONCLUSION SBRT treatment plans of Monaco agreed with MC results. It possible to use MC for treatment plans verifications as independent QC tool.
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Affiliation(s)
- Husein Alhamada
- Nuclear Metrology Department, Ecole Polytechnique, ULB, Brussels, Belgium.
| | - Stephane Simon
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
| | - Akos Gulyban
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
| | | | - Nicolas Pauly
- Nuclear Metrology Department, Ecole Polytechnique, ULB, Brussels, Belgium.
| | - Dirk VanGestel
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
| | - Nick Reynaert
- Radiotherapy Department, Institute Jules Bordet, Brussels, Belgium.
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Ezzati AO, Studenski MT, Gohari M. Spatial Mesh-Based Surface Source Model for the Electron Contamination of an 18 MV Photon Beams. J Med Phys 2021; 45:221-225. [PMID: 33953497 PMCID: PMC8074718 DOI: 10.4103/jmp.jmp_29_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 10/14/2020] [Accepted: 11/02/2020] [Indexed: 11/04/2022] Open
Abstract
Background Source modeling is an approach to reduce computational burden in Monte Carlo simulations but at the cost of reduced accuracy. Although this method can be effective, one component of the source model that is exceptionally difficult to model is the electron contamination, a significant contributor to the skin and shallow dose. Aims and Objectives To improve the accuracy for the electron contamination component of the overall source model, we have generated a spatial mesh based surface source model. Methods and Materials The source model is located downstream from the flattening filter and mirror but upstream from the movable jaws. A typical phase space file uses around ten parameters per particle, but this method simplifies this number to five components. By using only the electron distance from the central axis, angles from the central axis and energy, the computational time and disk space required is greatly reduced. Results and Conclusion Despite the simplification in the source model, the electron contamination is still accurate to within 1.5%.
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Affiliation(s)
- Ahad Ollah Ezzati
- Department of Nuclear Physics, Faculty of Physics, University of Tabriz, Tabriz, Iran
| | | | - Masuomeh Gohari
- Department of Nuclear Physics, Faculty of Physics, University of Tabriz, Tabriz, Iran
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The comparison between 6 MV Primus LINAC simulation output using EGSnrc and commissioning data. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396917000747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractIntroductionMonte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The purpose of this research is comparison between 6 MV Primus LINAC simulation output with commissioning data using EGSnrc and build a Monte Carlo geometry of 6 MV Primus LINAC as realistically as possible. The BEAMnrc and DOSXYZnrc (EGSnrc package) Monte Carlo model of the LINAC head was used as a benchmark.MethodsIn the first part, the BEAMnrc was used for the designing of the LINAC treatment head. In the second part, dose calculation and for the design of 3D dose file were produced by DOSXYZnrc. The simulated PDD and beam profile obtained were compared with that calculated using commissioning data. Good agreement was found between calculated PDD (1·1%) and beam profile using Monte Carlo simulation and commissioning data. After validation, TPR20,10, TMR and Spvalues were calculated in five different field.ResultsGood agreement was found between calculated values by using Monte Carlo simulation and commissioning data. Average differences for five field sizes in this approach is about 0·83% for Sp. for TPR20,10differences for field sizes 10×10 cm2is 0·29% and for TMR in five field sizes, the average value is ~1·6%.ConclusionIn conclusion, the BEAMnrc and DOSXYZnrc codes package have very good accuracy in calculating dose distribution for 6 MV photon beam and it can be considered as a promising method for patient dose calculations and also the Monte Carlo model of primus linear accelerator built in this study can be used as method to calculate the dose distribution for cancer patients.
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Ezzati AO, Xiao Y, Sohrabpour M, Studenski MT. The effect of energy spectrum change on DNA damage in and out of field in 10-MV clinical photon beams. Med Biol Eng Comput 2014; 53:67-75. [DOI: 10.1007/s11517-014-1213-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 10/20/2014] [Indexed: 10/24/2022]
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Conneely E, Alexander A, Stroian G, Seuntjens J, Foley MJ. An investigation into the use of MMCTP to tune accelerator source parameters and testing its clinical application. J Appl Clin Med Phys 2013; 14:3692. [PMID: 23470925 PMCID: PMC5714361 DOI: 10.1120/jacmp.v14i2.3692] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/18/2012] [Accepted: 10/09/2012] [Indexed: 11/23/2022] Open
Abstract
This paper presents an alternative method to tune Monte Carlo electron beam parameters to match measured data using a minimal set of variables in order to reduce the model setup time prior to clinical implementation of the model. Monte Carlo calculations provide the possibility of a powerful treatment planning verification technique. The nonstandardized and nonautomated process of tuning the required accelerator model is one of the reasons for delays in the clinical implementation of Monte Carlo techniques. This work aims to establish and verify an alternative tuning method that can be carried out in a minimal amount of time, allowing it to be easily implemented in a clinical setting by personnel with minimal experience with Monte Carlo methods. This tuned model can then be incorporated into the MMCTP system to allow the system to be used as a second dose calculation check for IMRT plans. The technique proposed was used to establish the primary electron beam parameters for accelerator models for the Varian Clinac 2100 6 MV photon beam using the BEAMnrc Monte Carlo system. The method is intended to provide a clear, direct, and efficient process for tuning an accelerator model using readily available clinical quality assurance data. The tuning provides a refined model, which agrees with measured dose profile curves within 1.5% outside the penumbra or 3 mm in the penumbra, for square fields with sides of 3 cm up to 30 cm. These models can then be employed as the basis for Monte Carlo recalculations of dose distributions, using the MMCTP system, for clinical treatment plans, providing an invaluable assessment tool. This was tested on six IMRT plans and compared to the measurements performed for the pretreatment QA process. These Monte Carlo values for the average dose to the chamber volume agreed with measurements to within 0.6%. PACS number: 87.55.km
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Almberg SS, Frengen J, Kylling A, Lindmo T. Monte Carlo linear accelerator simulation of megavoltage photon beams: Independent determination of initial beam parameters. Med Phys 2011; 39:40-7. [DOI: 10.1118/1.3668315] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Constantin M, Perl J, LoSasso T, Salop A, Whittum D, Narula A, Svatos M, Keall PJ. Modeling the TrueBeam linac using a CAD to Geant4 geometry implementation: Dose and IAEA-compliant phase space calculations. Med Phys 2011; 38:4018-24. [DOI: 10.1118/1.3598439] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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St. Aubin J, Santos DM, Steciw S, Fallone BG. Effect of longitudinal magnetic fields on a simulated in-line 6 MV linac. Med Phys 2010; 37:4916-23. [DOI: 10.1118/1.3481513] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Ottosson RO, Karlsson A, Behrens CF. Pareto front analysis of 6 and 15 MV dynamic IMRT for lung cancer using pencil beam, AAA and Monte Carlo. Phys Med Biol 2010; 55:4521-33. [DOI: 10.1088/0031-9155/55/16/s07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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St. Aubin J, Steciw S, Kirkby C, Fallone BG. An integrated 6 MV linear accelerator model from electron gun to dose in a water tank. Med Phys 2010; 37:2279-88. [DOI: 10.1118/1.3397455] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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St. Aubin J, Steciw S, Fallone BG. The design of a simulated in-line side-coupled 6 MV linear accelerator waveguide. Med Phys 2010; 37:466-76. [DOI: 10.1118/1.3276778] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Howell RM, Kry SF, Burgett E, Hertel NE, Followill DS. Secondary neutron spectra from modern Varian, Siemens, and Elekta linacs with multileaf collimators. Med Phys 2009; 36:4027-38. [PMID: 19810475 PMCID: PMC2738742 DOI: 10.1118/1.3159300] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Revised: 04/19/2009] [Accepted: 05/31/2009] [Indexed: 11/07/2022] Open
Abstract
Neutrons are a by-product of high-energy x-ray radiation therapy (threshold for [gamma,n] reactions in high-Z material -7 MeV). Neutron production varies depending on photon beam energy as well as on the manufacturer of the accelerator. Neutron production from modern linear accelerators (linacs) has not been extensively compared, particularly in terms of the differences in the strategies that various manufacturers have used to implement multileaf collimators (MLCs) into their linac designs. However, such information is necessary to determine neutron dose equivalents for different linacs and to calculate vault shielding requirements. The purpose of the current study, therefore, was to measure the neutron spectra from the most up-to-date linacs from three manufacturers: Varian 21EX operating at 15, 18, and 20 MV, Siemens ONCOR operating at 15 and 18 MV, and Elekta Precise operating at 15 and 18 MV. Neutron production was measured by means of gold foil activation in Bonner spheres. Based on the measurements, the authors determined neutron spectra and calculated the average energy, total neutron fluence, ambient dose equivalent, and neutron source strength. The shapes of the neutron spectra did not change significantly between accelerators or even as a function of treatment energy. However, the neutron fluence, and therefore the ambient dose equivalent, did vary, increasing with increasing treatment energy. For a given nominal treatment energy, these values were always highest for the Varian linac. The current study thus offers medical physicists extensive information about the neutron production of MLC-equipped linacs currently in operation and provides them information vital for accurate comparison and prediction of neutron dose equivalents and calculation of vault shielding requirements.
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Affiliation(s)
- Rebecca M Howell
- Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
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Becker J, Brunckhorst E, Schmidt R. Photoneutron production of a Siemens Primus linear accelerator studied by Monte Carlo methods and a paired magnesium and boron coated magnesium ionization chamber system. Phys Med Biol 2007; 52:6375-87. [DOI: 10.1088/0031-9155/52/21/002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Pena J, González-Castaño DM, Gómez F, Sánchez-Doblado F, Hartmann GH. Automatic determination of primary electron beam parameters in Monte Carlo simulation. Med Phys 2007; 34:1076-84. [PMID: 17441253 DOI: 10.1118/1.2514155] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In order to obtain realistic and reliable Monte Carlo simulations of medical linac photon beams, an accurate determination of the parameters that define the primary electron beam that hits the target is a fundamental step. In this work we propose a new methodology to commission photon beams in Monte Carlo simulations that ensures the reproducibility of a wide range of clinically useful fields. For such purpose accelerated Monte Carlo simulations of 2 x 2, 10 x 10, and 20 x 20 cm2 fields at SSD = 100 cm are carried out for several combinations of the primary electron beam mean energy and radial FWHM. Then, by performing a simultaneous comparison with the correspondent measurements for these same fields, the best combination is selected. This methodology has been employed to determine the characteristics of the primary electron beams that best reproduce a Siemens PRIMUS and a Varian 2100 CD machine in the Monte Carlo simulations. Excellent agreements were obtained between simulations and measurements for a wide range of field sizes. Because precalculated profiles are stored in databases, the whole commissioning process can be fully automated, avoiding manual fine-tunings. These databases can also be used to characterize any accelerators of the same model from different sites.
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Affiliation(s)
- Javier Pena
- Departamento de Física de Partículas, Facultade de Física, Universidade de Santiago de Compostela, Spain.
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Wang LLW, Leszczynski K. Estimation of the focal spot size and shape for a medical linear accelerator by Monte Carlo simulation. Med Phys 2007; 34:485-8. [PMID: 17388165 DOI: 10.1118/1.2426407] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The focal spot size and shape of a medical linac are important parameters that determine the dose profiles, especially in the penumbral region. A relationship between the focal spot size and the dose profile penumbra has been studied and established from simulation results of the EGSnrc Monte Carlo code. A simple method is proposed to estimate the size and the shape of a linac's focal spot from the measured dose profile data.
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Affiliation(s)
- Lilie L W Wang
- Department of Physics, Laurentian University, Sudbury, Ontario, Canada P3E 2C5.
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Pena J, Franco L, Gómez F, Iglesias A, Pardo J, Pombar M. Monte Carlo study of Siemens PRIMUS photoneutron production. Phys Med Biol 2005; 50:5921-33. [PMID: 16333164 DOI: 10.1088/0031-9155/50/24/011] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neutron production in radiotherapy facilities has been studied from the early days of modern linacs. Detailed studies are now possible using photoneutron capabilities of general-purpose Monte Carlo codes at energies of interest in medical physics. The present work studies the effects of modelling different accelerator head and room geometries on the neutron fluence and spectra predicted via Monte Carlo. The results from the simulation of a 15 MV Siemens PRIMUS linac show an 80% increase in the fluence scored at the isocentre when, besides modelling the components necessary for electron/photon simulations, other massive accelerator head components are included. Neutron fluence dependence on inner treatment room volume is analysed showing that thermal neutrons have a 'gaseous' behaviour and then a 1/V dependence. Neutron fluence maps for three energy ranges, fast (E > 0.1 MeV), epithermal (1 eV < E < 0.1 MeV) and thermal (E < 1 eV), are also presented and the influence of the head components on them is discussed.
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Affiliation(s)
- J Pena
- Departamento de Física de Partículas, Facultade de Física, 15 782 Santiago de Compostela, Spain
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