Document Type : Original Research
Authors
1 Physics Department, School of Sciences, Payame Noor University of Mashhad, Mashhad, Iran
2 Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran
3 ICTP, Associate Federation Scheme, Medical Physics Field, Trieste, Italy
4 Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Abstract
Objective: The aim of the present study is to simulate 6 MV and 18 MV photon beam energies of a Siemens Primus Plus medical linear accelerator (Linac) and to verify the simulation by comparing the results with the measured data.Methods: The main components of the head of Siemens Primus Plus linac were simulated using MCNPX Monte Carlo (MC) code. To verify the results, experimental data of percentage depth dose (PDD) and beam dose profile for 5 × 5 cm2, 10 × 10 cm2 and 20 × 20 cm2 field sizes were measured and compared with simulation results. Moreover, gamma function was used to compare the measurement and simulation data.Results: The results show a good agreement, within 1%, was observed between the data calculated by the simulations and those obtained by measurement for 6 MV photon beam, while it was within 2% for 18 MV photon beam, except in the build-up region for both beams. Gamma index values were less than unity in most data points for all the mentioned energies and fields. To calculate the dose in the phantom, cells were selected in different modes, one of the modes due to the lack of dose gradient and overlapping, produced better results than others produce.Conclusion: There was good settlement between measured and MC simulation values in this research. The simulation programs can be used for photon modes of Siemens Primus Plus linac in conditions in which it is not possible to perform experimental measurements.
Keywords
- Vega-Carrillo HR, Martinez-Ovalle SA, Lallena AM, Mercado GA, Benites-Rengifo JL. Neutron and photon spectra in LINACs. Appl Radiat Isot. 2012;71:75-80. doi.org/10.1016/j.apradiso.2012.03.034. PubMed PMID: 22494894.
- Becker J. Simulation of neutron production at a medical linear accelerator: Diploma thesis, Department of Physics, University of Hamburg performed at the University Medical Center Hamburg-Eppendorf, Department of Radiotherapy and Radio-Oncology, Medical Physics; 2007.
- Ma CM, Jiang SB. Monte Carlo modelling of electron beams from medical accelerators. Phys Med Biol. 1999;44:R157-89. doi.org/10.1088/0031-9155/44/12/201. PubMed PMID: 10616140.
- Bahreyni Toosi M, Momen Nezhad M, Saberi H, Bahreyni Toosi M, Hashemian A, Salek R, et al. A Monte Carlo simulation of photon beam generated by a linear accelerator. Iranian Journal of Medical Physics. 2005;2:3-12.
- Aljamal M, Zakaria A. Monte Carlo Modeling of a Siemens Primus 6 MV Photon Beam Linear Accelerator. Australian Journal of Basic and Applied Sciences. 2013;7:340-6.
- Grevillot L, Frisson T, Maneval D, Zahra N, Badel JN, Sarrut D. Simulation of a 6 MV Elekta Precise Linac photon beam using GATE/GEANT4. Phys Med Biol. 2011;56:903-18. doi.org/10.1088/0031-9155/56/4/002. PubMed PMID: 21248389.
- Sardari D, Maleki R, Samavat H, Esmaeeli A. Measurement of depth-dose of linear accelerator and simulation by use of Geant4 computer code. Rep Pract Oncol Radiother. 2010;15:64-8. doi.org/10.1016/j.rpor.2010.03.001. PubMed PMID: 24376926. PubMed PMCID: 3863189.
- 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.org/10.1088/0031-9155/52/21/002. PubMed PMID: 17951849.
- Mohammadi N, Miri Hakimabad SH, Rafat Motavali L, Akbari F, Abdollahi S. Neutron spectrometry and determination of neutron contamination around the 15 MV Siemens Primus LINAC. Journal of Radioanalytical and Nuclear Chemistry. 2015;304. doi.org/10.1007/s10967-015-3944-5.
- Chetty IJ, Curran B, Cygler JE, DeMarco JJ, Ezzell G, Faddegon BA, et al. Report of the AAPM Task Group No. 105: Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning. Med Phys. 2007;34:4818-53. doi.org/10.1118/1.2795842. PubMed PMID: 18196810.
- Mckinney G, Durkee J, Hendricks J, James M, Pelowitz D. MCNPX USERS MANUAL, Version 2.7. 0. LA-CP-11-00438,“LANL, Los Alamos, 2011.
- Allahverdi M, Zabihzadeh M, Ay M, Mahdavi S, Shahriari M, Mesbahi A, et al. Monte Carlo estimation of electron contamination in a 18 MV clinical photon beam. Iranian Journal of Radiation Research. 2011;9:15.
- Low DA, Harms WB, Mutic S, Purdy JA. A technique for the quantitative evaluation of dose distributions. Med Phys. 1998;25:656-61. doi.org/10.1118/1.598248. PubMed PMID: 9608475.
- Toossi MTB, Ghorbani M, Akbari F, Sabet LS, Mehrpouyan M. Monte Carlo simulation of electron modes of a Siemens Primus linac (8, 12 and 14 MeV). Journal of Radiotherapy in Practice. 2013;12:352-9. doi.org/10.1017/S1460396912000593.
- Depuydt T, Van Esch A, Huyskens DP. A quantitative evaluation of IMRT dose distributions: refinement and clinical assessment of the gamma evaluation. Radiother Oncol. 2002;62:309-19. doi.org/10.1016/S0167-8140(01)00497-2. PubMed PMID: 12175562.
- Tzedakis A, Damilakis JE, Mazonakis M, Stratakis J, Varveris H, Gourtsoyiannis N. Influence of initial electron beam parameters on Monte Carlo calculated absorbed dose distributions for radiotherapy photon beams. Med Phys. 2004;31:907-13. doi.org/10.1118/1.1668551. PubMed PMID: 15125009.
)